From patchwork Wed Jun 7 16:55:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791856 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=YM/mBSnv; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4Qbv703srGz20WP for ; Thu, 8 Jun 2023 03:13:00 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Qbv702GRWz3f5F for ; Thu, 8 Jun 2023 03:13:00 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=YM/mBSnv; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4641:c500::1; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=YM/mBSnv; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4QbtsF1Q44z3dyf for ; Thu, 8 Jun 2023 03:01:05 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 70FBD60B60; Wed, 7 Jun 2023 17:01:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D98CC433EF; Wed, 7 Jun 2023 17:01:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157262; bh=Iw1Dv20up6Z064YBBB74k6x5kv8HOFxX1mSlj8e9zYU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YM/mBSnvpLpf/0/46bGpbt0duq2gHpJXKWNZwXwPvNflxLgFY5JNQpIqnqamXZZ9h ZAa+Etk2IagOstLe33UXqryYx7OzBORe6eZvSKVYk1Nrkpib4GcdakTEr9QwgkUYb7 NbnCMPZw2Sv5Q3oTaa3D+JGKAaAKVmVDHCev65jP00no4MlVg1U6iDb1DXzErK9HD/ BsBh9AVbfz7FNg2FlncSqVm4yF4xvgpGpzeuj4bQgZb97AlJSmtQATNutHCNXOkiDQ oV0eJjVcDdtUCTUoOFntDtOwIUsANovg0JoMSCu47ys+I6l6TfLBAYmu/fG1K2L770 kpe0/yhXhbqaA== From: Naveen N Rao To: Subject: [RFC PATCH 01/15] powerpc/module: Remove unused .ftrace.tramp section Date: Wed, 7 Jun 2023 22:25:16 +0530 Message-Id: <8b73187ee4236162cfb6a3165a9f4c38876cef64.1686151854.git.naveen@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" .ftrace.tramp section is not used for any purpose. This code was added all the way back in the original commit introducing support for dynamic ftrace on ppc64 modules. Remove it. Signed-off-by: Naveen N Rao --- arch/powerpc/include/asm/module.h | 4 ---- 1 file changed, 4 deletions(-) diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h index ac53606c259430..a8e2e8339fb7f4 100644 --- a/arch/powerpc/include/asm/module.h +++ b/arch/powerpc/include/asm/module.h @@ -75,10 +75,6 @@ struct mod_arch_specific { #endif #ifdef CONFIG_DYNAMIC_FTRACE -# ifdef MODULE - asm(".section .ftrace.tramp,\"ax\",@nobits; .align 3; .previous"); -# endif /* MODULE */ - int module_trampoline_target(struct module *mod, unsigned long trampoline, unsigned long *target); int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs); From patchwork Wed Jun 7 16:55:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791843 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=unxpSo/n; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4QbtyH3f7Dz20Ty for ; Thu, 8 Jun 2023 03:05:27 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4QbtyH19DQz3dwL for ; Thu, 8 Jun 2023 03:05:27 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=unxpSo/n; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4641:c500::1; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=unxpSo/n; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4QbtrS2mP3z3dwF for ; Thu, 8 Jun 2023 03:00:24 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A220560A49; Wed, 7 Jun 2023 17:00:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55541C4339B; Wed, 7 Jun 2023 17:00:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157222; bh=PSfFBoSGu4k/xQfpRcfxKY0ifx/FH6efZ67001q3tqg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=unxpSo/nc6nqJ2kubaUl4eES9ONbKW/D+iYztQym5nK0kXFGA209RQiWdQcvHuQCl HqBLesSvTiLBA0c32/dWfkuIr+R6PM/InbLSZFNJsIgzXpCDuYtkYUZOqHn0S2FbM6 AkUqVoptflTF1RJUtoEzgvN8Yuf/eHTqfvxw2381suQIopAIMKg0qMirxx5Wz2ahT6 M1RCVVYY9IfbLGZ1mWHPWiDI1d4NW179+h8/2AtQ9eOuCn9rmlame9M+qQ8L/hL3Rp hm4JOTJ3SJqOnYqP8c8uMK1U5D5wNLVW1Yecnynzp++lwosNNh51ITJ/jVG0dNdmjC WXSTUYkY7mNoQ== From: Naveen N Rao To: Subject: [RFC PATCH 02/15] powerpc64/ftrace: Move ELFv1 and -pg support code into a separate file Date: Wed, 7 Jun 2023 22:25:17 +0530 Message-Id: <08e9e5983eeb04e77a11206151b96011fb04fb55.1686151854.git.naveen@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" ELFv1 support is deprecated and on the way out. Pre -mprofile-kernel ftrace support (-pg only) is very limited and is retained primarily for clang builds. It won't be necessary once clang lands support for -fpatchable-function-entry. Copy the existing ftrace code supporting these into ftrace_pg.c. ftrace.c can then be refactored and enhanced with a focus on ppc32 and ppc64 ELFv2. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/Makefile | 13 +- arch/powerpc/kernel/trace/ftrace.c | 10 - arch/powerpc/kernel/trace/ftrace_pg.c | 846 ++++++++++++++++++++++++++ 3 files changed, 855 insertions(+), 14 deletions(-) create mode 100644 arch/powerpc/kernel/trace/ftrace_pg.c diff --git a/arch/powerpc/kernel/trace/Makefile b/arch/powerpc/kernel/trace/Makefile index b16a9f9c0b35f2..342a2d1ae86cd0 100644 --- a/arch/powerpc/kernel/trace/Makefile +++ b/arch/powerpc/kernel/trace/Makefile @@ -6,15 +6,16 @@ ifdef CONFIG_FUNCTION_TRACER # do not trace tracer code CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_ftrace_pg.o = $(CC_FLAGS_FTRACE) endif -obj32-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o +obj32-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o ftrace.o ifdef CONFIG_MPROFILE_KERNEL -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o ftrace.o else -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o ftrace_pg.o endif -obj-$(CONFIG_FUNCTION_TRACER) += ftrace_low.o ftrace.o +obj-$(CONFIG_FUNCTION_TRACER) += ftrace_low.o obj-$(CONFIG_TRACING) += trace_clock.o obj-$(CONFIG_PPC64) += $(obj64-y) @@ -25,3 +26,7 @@ GCOV_PROFILE_ftrace.o := n KCOV_INSTRUMENT_ftrace.o := n KCSAN_SANITIZE_ftrace.o := n UBSAN_SANITIZE_ftrace.o := n +GCOV_PROFILE_ftrace_pg.o := n +KCOV_INSTRUMENT_ftrace_pg.o := n +KCSAN_SANITIZE_ftrace_pg.o := n +UBSAN_SANITIZE_ftrace_pg.o := n diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index a47f303734233b..81a121b56c4d7f 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -864,13 +864,3 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, } #endif #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ - -#ifdef CONFIG_PPC64_ELF_ABI_V1 -char *arch_ftrace_match_adjust(char *str, const char *search) -{ - if (str[0] == '.' && search[0] != '.') - return str + 1; - else - return str; -} -#endif /* CONFIG_PPC64_ELF_ABI_V1 */ diff --git a/arch/powerpc/kernel/trace/ftrace_pg.c b/arch/powerpc/kernel/trace/ftrace_pg.c new file mode 100644 index 00000000000000..7b85c3b460a3c0 --- /dev/null +++ b/arch/powerpc/kernel/trace/ftrace_pg.c @@ -0,0 +1,846 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Code for replacing ftrace calls with jumps. + * + * Copyright (C) 2007-2008 Steven Rostedt + * + * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box. + * + * Added function graph tracer code, taken from x86 that was written + * by Frederic Weisbecker, and ported to PPC by Steven Rostedt. + * + */ + +#define pr_fmt(fmt) "ftrace-powerpc: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +/* + * We generally only have a single long_branch tramp and at most 2 or 3 plt + * tramps generated. But, we don't use the plt tramps currently. We also allot + * 2 tramps after .text and .init.text. So, we only end up with around 3 usable + * tramps in total. Set aside 8 just to be sure. + */ +#define NUM_FTRACE_TRAMPS 8 +static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; + +static ppc_inst_t +ftrace_call_replace(unsigned long ip, unsigned long addr, int link) +{ + ppc_inst_t op; + + addr = ppc_function_entry((void *)addr); + + /* if (link) set op to 'bl' else 'b' */ + create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0); + + return op; +} + +static inline int +ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) +{ + ppc_inst_t replaced; + + /* + * Note: + * We are paranoid about modifying text, as if a bug was to happen, it + * could cause us to read or write to someplace that could cause harm. + * Carefully read and modify the code with probe_kernel_*(), and make + * sure what we read is what we expected it to be before modifying it. + */ + + /* read the text we want to modify */ + if (copy_inst_from_kernel_nofault(&replaced, (void *)ip)) + return -EFAULT; + + /* Make sure it is what we expect it to be */ + if (!ppc_inst_equal(replaced, old)) { + pr_err("%p: replaced (%08lx) != old (%08lx)", (void *)ip, + ppc_inst_as_ulong(replaced), ppc_inst_as_ulong(old)); + return -EINVAL; + } + + /* replace the text with the new text */ + return patch_instruction((u32 *)ip, new); +} + +/* + * Helper functions that are the same for both PPC64 and PPC32. + */ +static int test_24bit_addr(unsigned long ip, unsigned long addr) +{ + addr = ppc_function_entry((void *)addr); + + return is_offset_in_branch_range(addr - ip); +} + +static int is_bl_op(ppc_inst_t op) +{ + return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0); +} + +static int is_b_op(ppc_inst_t op) +{ + return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BRANCH(0); +} + +static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) +{ + int offset; + + offset = PPC_LI(ppc_inst_val(op)); + /* make it signed */ + if (offset & 0x02000000) + offset |= 0xfe000000; + + return ip + (long)offset; +} + +#ifdef CONFIG_MODULES +static int +__ftrace_make_nop(struct module *mod, + struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned long entry, ptr, tramp; + unsigned long ip = rec->ip; + ppc_inst_t op, pop; + + /* read where this goes */ + if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { + pr_err("Fetching opcode failed.\n"); + return -EFAULT; + } + + /* Make sure that this is still a 24bit jump */ + if (!is_bl_op(op)) { + pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); + return -EINVAL; + } + + /* lets find where the pointer goes */ + tramp = find_bl_target(ip, op); + + pr_devel("ip:%lx jumps to %lx", ip, tramp); + + if (module_trampoline_target(mod, tramp, &ptr)) { + pr_err("Failed to get trampoline target\n"); + return -EFAULT; + } + + pr_devel("trampoline target %lx", ptr); + + entry = ppc_global_function_entry((void *)addr); + /* This should match what was called */ + if (ptr != entry) { + pr_err("addr %lx does not match expected %lx\n", ptr, entry); + return -EINVAL; + } + + if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) { + if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 4))) { + pr_err("Fetching instruction at %lx failed.\n", ip - 4); + return -EFAULT; + } + + /* We expect either a mflr r0, or a std r0, LRSAVE(r1) */ + if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_MFLR(_R0))) && + !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) { + pr_err("Unexpected instruction %08lx around bl _mcount\n", + ppc_inst_as_ulong(op)); + return -EINVAL; + } + } else if (IS_ENABLED(CONFIG_PPC64)) { + /* + * Check what is in the next instruction. We can see ld r2,40(r1), but + * on first pass after boot we will see mflr r0. + */ + if (copy_inst_from_kernel_nofault(&op, (void *)(ip + 4))) { + pr_err("Fetching op failed.\n"); + return -EFAULT; + } + + if (!ppc_inst_equal(op, ppc_inst(PPC_INST_LD_TOC))) { + pr_err("Expected %08lx found %08lx\n", PPC_INST_LD_TOC, + ppc_inst_as_ulong(op)); + return -EINVAL; + } + } + + /* + * When using -mprofile-kernel or PPC32 there is no load to jump over. + * + * Otherwise our original call site looks like: + * + * bl + * ld r2,XX(r1) + * + * Milton Miller pointed out that we can not simply nop the branch. + * If a task was preempted when calling a trace function, the nops + * will remove the way to restore the TOC in r2 and the r2 TOC will + * get corrupted. + * + * Use a b +8 to jump over the load. + */ + if (IS_ENABLED(CONFIG_MPROFILE_KERNEL) || IS_ENABLED(CONFIG_PPC32)) + pop = ppc_inst(PPC_RAW_NOP()); + else + pop = ppc_inst(PPC_RAW_BRANCH(8)); /* b +8 */ + + if (patch_instruction((u32 *)ip, pop)) { + pr_err("Patching NOP failed.\n"); + return -EPERM; + } + + return 0; +} +#else +static int __ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) +{ + return 0; +} +#endif /* CONFIG_MODULES */ + +static unsigned long find_ftrace_tramp(unsigned long ip) +{ + int i; + + /* + * We have the compiler generated long_branch tramps at the end + * and we prefer those + */ + for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--) + if (!ftrace_tramps[i]) + continue; + else if (is_offset_in_branch_range(ftrace_tramps[i] - ip)) + return ftrace_tramps[i]; + + return 0; +} + +static int add_ftrace_tramp(unsigned long tramp) +{ + int i; + + for (i = 0; i < NUM_FTRACE_TRAMPS; i++) + if (!ftrace_tramps[i]) { + ftrace_tramps[i] = tramp; + return 0; + } + + return -1; +} + +/* + * If this is a compiler generated long_branch trampoline (essentially, a + * trampoline that has a branch to _mcount()), we re-write the branch to + * instead go to ftrace_[regs_]caller() and note down the location of this + * trampoline. + */ +static int setup_mcount_compiler_tramp(unsigned long tramp) +{ + int i; + ppc_inst_t op; + unsigned long ptr; + + /* Is this a known long jump tramp? */ + for (i = 0; i < NUM_FTRACE_TRAMPS; i++) + if (ftrace_tramps[i] == tramp) + return 0; + + /* New trampoline -- read where this goes */ + if (copy_inst_from_kernel_nofault(&op, (void *)tramp)) { + pr_debug("Fetching opcode failed.\n"); + return -1; + } + + /* Is this a 24 bit branch? */ + if (!is_b_op(op)) { + pr_debug("Trampoline is not a long branch tramp.\n"); + return -1; + } + + /* lets find where the pointer goes */ + ptr = find_bl_target(tramp, op); + + if (ptr != ppc_global_function_entry((void *)_mcount)) { + pr_debug("Trampoline target %p is not _mcount\n", (void *)ptr); + return -1; + } + + /* Let's re-write the tramp to go to ftrace_[regs_]caller */ + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + ptr = ppc_global_function_entry((void *)ftrace_regs_caller); + else + ptr = ppc_global_function_entry((void *)ftrace_caller); + + if (patch_branch((u32 *)tramp, ptr, 0)) { + pr_debug("REL24 out of range!\n"); + return -1; + } + + if (add_ftrace_tramp(tramp)) { + pr_debug("No tramp locations left\n"); + return -1; + } + + return 0; +} + +static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned long tramp, ip = rec->ip; + ppc_inst_t op; + + /* Read where this goes */ + if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { + pr_err("Fetching opcode failed.\n"); + return -EFAULT; + } + + /* Make sure that this is still a 24bit jump */ + if (!is_bl_op(op)) { + pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); + return -EINVAL; + } + + /* Let's find where the pointer goes */ + tramp = find_bl_target(ip, op); + + pr_devel("ip:%lx jumps to %lx", ip, tramp); + + if (setup_mcount_compiler_tramp(tramp)) { + /* Are other trampolines reachable? */ + if (!find_ftrace_tramp(ip)) { + pr_err("No ftrace trampolines reachable from %ps\n", + (void *)ip); + return -EINVAL; + } + } + + if (patch_instruction((u32 *)ip, ppc_inst(PPC_RAW_NOP()))) { + pr_err("Patching NOP failed.\n"); + return -EPERM; + } + + return 0; +} + +int ftrace_make_nop(struct module *mod, + struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned long ip = rec->ip; + ppc_inst_t old, new; + + /* + * If the calling address is more that 24 bits away, + * then we had to use a trampoline to make the call. + * Otherwise just update the call site. + */ + if (test_24bit_addr(ip, addr)) { + /* within range */ + old = ftrace_call_replace(ip, addr, 1); + new = ppc_inst(PPC_RAW_NOP()); + return ftrace_modify_code(ip, old, new); + } else if (core_kernel_text(ip)) { + return __ftrace_make_nop_kernel(rec, addr); + } else if (!IS_ENABLED(CONFIG_MODULES)) { + return -EINVAL; + } + + /* + * Out of range jumps are called from modules. + * We should either already have a pointer to the module + * or it has been passed in. + */ + if (!rec->arch.mod) { + if (!mod) { + pr_err("No module loaded addr=%lx\n", addr); + return -EFAULT; + } + rec->arch.mod = mod; + } else if (mod) { + if (mod != rec->arch.mod) { + pr_err("Record mod %p not equal to passed in mod %p\n", + rec->arch.mod, mod); + return -EINVAL; + } + /* nothing to do if mod == rec->arch.mod */ + } else + mod = rec->arch.mod; + + return __ftrace_make_nop(mod, rec, addr); +} + +#ifdef CONFIG_MODULES +/* + * Examine the existing instructions for __ftrace_make_call. + * They should effectively be a NOP, and follow formal constraints, + * depending on the ABI. Return false if they don't. + */ +static bool expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1) +{ + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())); + else + return ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) && + ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC)); +} + +static int +__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + ppc_inst_t op[2]; + void *ip = (void *)rec->ip; + unsigned long entry, ptr, tramp; + struct module *mod = rec->arch.mod; + + /* read where this goes */ + if (copy_inst_from_kernel_nofault(op, ip)) + return -EFAULT; + + if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && + copy_inst_from_kernel_nofault(op + 1, ip + 4)) + return -EFAULT; + + if (!expected_nop_sequence(ip, op[0], op[1])) { + pr_err("Unexpected call sequence at %p: %08lx %08lx\n", ip, + ppc_inst_as_ulong(op[0]), ppc_inst_as_ulong(op[1])); + return -EINVAL; + } + + /* If we never set up ftrace trampoline(s), then bail */ + if (!mod->arch.tramp || + (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !mod->arch.tramp_regs)) { + pr_err("No ftrace trampoline\n"); + return -EINVAL; + } + + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && rec->flags & FTRACE_FL_REGS) + tramp = mod->arch.tramp_regs; + else + tramp = mod->arch.tramp; + + if (module_trampoline_target(mod, tramp, &ptr)) { + pr_err("Failed to get trampoline target\n"); + return -EFAULT; + } + + pr_devel("trampoline target %lx", ptr); + + entry = ppc_global_function_entry((void *)addr); + /* This should match what was called */ + if (ptr != entry) { + pr_err("addr %lx does not match expected %lx\n", ptr, entry); + return -EINVAL; + } + + if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { + pr_err("REL24 out of range!\n"); + return -EINVAL; + } + + return 0; +} +#else +static int __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + return 0; +} +#endif /* CONFIG_MODULES */ + +static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr) +{ + ppc_inst_t op; + void *ip = (void *)rec->ip; + unsigned long tramp, entry, ptr; + + /* Make sure we're being asked to patch branch to a known ftrace addr */ + entry = ppc_global_function_entry((void *)ftrace_caller); + ptr = ppc_global_function_entry((void *)addr); + + if (ptr != entry && IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + entry = ppc_global_function_entry((void *)ftrace_regs_caller); + + if (ptr != entry) { + pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr); + return -EINVAL; + } + + /* Make sure we have a nop */ + if (copy_inst_from_kernel_nofault(&op, ip)) { + pr_err("Unable to read ftrace location %p\n", ip); + return -EFAULT; + } + + if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) { + pr_err("Unexpected call sequence at %p: %08lx\n", + ip, ppc_inst_as_ulong(op)); + return -EINVAL; + } + + tramp = find_ftrace_tramp((unsigned long)ip); + if (!tramp) { + pr_err("No ftrace trampolines reachable from %ps\n", ip); + return -EINVAL; + } + + if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { + pr_err("Error patching branch to ftrace tramp!\n"); + return -EINVAL; + } + + return 0; +} + +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned long ip = rec->ip; + ppc_inst_t old, new; + + /* + * If the calling address is more that 24 bits away, + * then we had to use a trampoline to make the call. + * Otherwise just update the call site. + */ + if (test_24bit_addr(ip, addr)) { + /* within range */ + old = ppc_inst(PPC_RAW_NOP()); + new = ftrace_call_replace(ip, addr, 1); + return ftrace_modify_code(ip, old, new); + } else if (core_kernel_text(ip)) { + return __ftrace_make_call_kernel(rec, addr); + } else if (!IS_ENABLED(CONFIG_MODULES)) { + /* We should not get here without modules */ + return -EINVAL; + } + + /* + * Out of range jumps are called from modules. + * Being that we are converting from nop, it had better + * already have a module defined. + */ + if (!rec->arch.mod) { + pr_err("No module loaded\n"); + return -EINVAL; + } + + return __ftrace_make_call(rec, addr); +} + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +#ifdef CONFIG_MODULES +static int +__ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr) +{ + ppc_inst_t op; + unsigned long ip = rec->ip; + unsigned long entry, ptr, tramp; + struct module *mod = rec->arch.mod; + + /* If we never set up ftrace trampolines, then bail */ + if (!mod->arch.tramp || !mod->arch.tramp_regs) { + pr_err("No ftrace trampoline\n"); + return -EINVAL; + } + + /* read where this goes */ + if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { + pr_err("Fetching opcode failed.\n"); + return -EFAULT; + } + + /* Make sure that this is still a 24bit jump */ + if (!is_bl_op(op)) { + pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); + return -EINVAL; + } + + /* lets find where the pointer goes */ + tramp = find_bl_target(ip, op); + entry = ppc_global_function_entry((void *)old_addr); + + pr_devel("ip:%lx jumps to %lx", ip, tramp); + + if (tramp != entry) { + /* old_addr is not within range, so we must have used a trampoline */ + if (module_trampoline_target(mod, tramp, &ptr)) { + pr_err("Failed to get trampoline target\n"); + return -EFAULT; + } + + pr_devel("trampoline target %lx", ptr); + + /* This should match what was called */ + if (ptr != entry) { + pr_err("addr %lx does not match expected %lx\n", ptr, entry); + return -EINVAL; + } + } + + /* The new target may be within range */ + if (test_24bit_addr(ip, addr)) { + /* within range */ + if (patch_branch((u32 *)ip, addr, BRANCH_SET_LINK)) { + pr_err("REL24 out of range!\n"); + return -EINVAL; + } + + return 0; + } + + if (rec->flags & FTRACE_FL_REGS) + tramp = mod->arch.tramp_regs; + else + tramp = mod->arch.tramp; + + if (module_trampoline_target(mod, tramp, &ptr)) { + pr_err("Failed to get trampoline target\n"); + return -EFAULT; + } + + pr_devel("trampoline target %lx", ptr); + + entry = ppc_global_function_entry((void *)addr); + /* This should match what was called */ + if (ptr != entry) { + pr_err("addr %lx does not match expected %lx\n", ptr, entry); + return -EINVAL; + } + + if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) { + pr_err("REL24 out of range!\n"); + return -EINVAL; + } + + return 0; +} +#else +static int __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) +{ + return 0; +} +#endif + +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr) +{ + unsigned long ip = rec->ip; + ppc_inst_t old, new; + + /* + * If the calling address is more that 24 bits away, + * then we had to use a trampoline to make the call. + * Otherwise just update the call site. + */ + if (test_24bit_addr(ip, addr) && test_24bit_addr(ip, old_addr)) { + /* within range */ + old = ftrace_call_replace(ip, old_addr, 1); + new = ftrace_call_replace(ip, addr, 1); + return ftrace_modify_code(ip, old, new); + } else if (core_kernel_text(ip)) { + /* + * We always patch out of range locations to go to the regs + * variant, so there is nothing to do here + */ + return 0; + } else if (!IS_ENABLED(CONFIG_MODULES)) { + /* We should not get here without modules */ + return -EINVAL; + } + + /* + * Out of range jumps are called from modules. + */ + if (!rec->arch.mod) { + pr_err("No module loaded\n"); + return -EINVAL; + } + + return __ftrace_modify_call(rec, old_addr, addr); +} +#endif + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + unsigned long ip = (unsigned long)(&ftrace_call); + ppc_inst_t old, new; + int ret; + + old = ppc_inst_read((u32 *)&ftrace_call); + new = ftrace_call_replace(ip, (unsigned long)func, 1); + ret = ftrace_modify_code(ip, old, new); + + /* Also update the regs callback function */ + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) { + ip = (unsigned long)(&ftrace_regs_call); + old = ppc_inst_read((u32 *)&ftrace_regs_call); + new = ftrace_call_replace(ip, (unsigned long)func, 1); + ret = ftrace_modify_code(ip, old, new); + } + + return ret; +} + +/* + * Use the default ftrace_modify_all_code, but without + * stop_machine(). + */ +void arch_ftrace_update_code(int command) +{ + ftrace_modify_all_code(command); +} + +#ifdef CONFIG_PPC64 +#define PACATOC offsetof(struct paca_struct, kernel_toc) + +extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; + +void ftrace_free_init_tramp(void) +{ + int i; + + for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++) + if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) { + ftrace_tramps[i] = 0; + return; + } +} + +int __init ftrace_dyn_arch_init(void) +{ + int i; + unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init }; + u32 stub_insns[] = { + PPC_RAW_LD(_R12, _R13, PACATOC), + PPC_RAW_ADDIS(_R12, _R12, 0), + PPC_RAW_ADDI(_R12, _R12, 0), + PPC_RAW_MTCTR(_R12), + PPC_RAW_BCTR() + }; + unsigned long addr; + long reladdr; + + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + addr = ppc_global_function_entry((void *)ftrace_regs_caller); + else + addr = ppc_global_function_entry((void *)ftrace_caller); + + reladdr = addr - kernel_toc_addr(); + + if (reladdr >= SZ_2G || reladdr < -(long)SZ_2G) { + pr_err("Address of %ps out of range of kernel_toc.\n", + (void *)addr); + return -1; + } + + for (i = 0; i < 2; i++) { + memcpy(tramp[i], stub_insns, sizeof(stub_insns)); + tramp[i][1] |= PPC_HA(reladdr); + tramp[i][2] |= PPC_LO(reladdr); + add_ftrace_tramp((unsigned long)tramp[i]); + } + + return 0; +} +#endif + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + +extern void ftrace_graph_call(void); +extern void ftrace_graph_stub(void); + +static int ftrace_modify_ftrace_graph_caller(bool enable) +{ + unsigned long ip = (unsigned long)(&ftrace_graph_call); + unsigned long addr = (unsigned long)(&ftrace_graph_caller); + unsigned long stub = (unsigned long)(&ftrace_graph_stub); + ppc_inst_t old, new; + + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS)) + return 0; + + old = ftrace_call_replace(ip, enable ? stub : addr, 0); + new = ftrace_call_replace(ip, enable ? addr : stub, 0); + + return ftrace_modify_code(ip, old, new); +} + +int ftrace_enable_ftrace_graph_caller(void) +{ + return ftrace_modify_ftrace_graph_caller(true); +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + return ftrace_modify_ftrace_graph_caller(false); +} + +/* + * Hook the return address and push it in the stack of return addrs + * in current thread info. Return the address we want to divert to. + */ +static unsigned long +__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp) +{ + unsigned long return_hooker; + int bit; + + if (unlikely(ftrace_graph_is_dead())) + goto out; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + goto out; + + bit = ftrace_test_recursion_trylock(ip, parent); + if (bit < 0) + goto out; + + return_hooker = ppc_function_entry(return_to_handler); + + if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp)) + parent = return_hooker; + + ftrace_test_recursion_unlock(bit); +out: + return parent; +} + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs) +{ + fregs->regs.link = __prepare_ftrace_return(parent_ip, ip, fregs->regs.gpr[1]); +} +#else +unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, + unsigned long sp) +{ + return __prepare_ftrace_return(parent, ip, sp); +} +#endif +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_PPC64_ELF_ABI_V1 +char *arch_ftrace_match_adjust(char *str, const char *search) +{ + if (str[0] == '.' && search[0] != '.') + return str + 1; + else + return str; +} +#endif /* CONFIG_PPC64_ELF_ABI_V1 */ From patchwork Wed Jun 7 16:55:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791844 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=eV0rC/Lt; 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receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=eV0rC/Lt; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4QbtrX6BTdz3dtF for ; Thu, 8 Jun 2023 03:00:28 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3BC6660A49; Wed, 7 Jun 2023 17:00:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 26687C433EF; Wed, 7 Jun 2023 17:00:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157226; bh=fiYOSGx/yX+rBoVWfDjzvuQpt+N/h7M6dfetR+JOhWA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eV0rC/LtetQix5E41W2bB4ApGRWYeHzTUGdmxJZQyb5+zfpp+mfv6wdWbRqzGWtYb r2nIEXuUioRwQ52+3AcFYsm8+zBw4hYBcrJkaO3RsOYdyPmzjtpKqexC7yQ0gv74VN RBPTXbvvh0/AQfq2uCK8C8GLtPhspW8PZOJZiZksxnVMsOIEeloHjoVDD6qVj8+aD2 gfLOFG9bZnFfhhU9QKcN85NMtC7lZXTu3coXDQDRGCd5VkIoTzqeunzPeFbxTEKo6J Ewta4dtZOI0UmVGUqUW5YvvDbbP75usi/sUS2vhhB8vBbB2JI2Ol6OjVu93NNlvmfg 5qmTf4wF6um3A== From: Naveen N Rao To: Subject: [RFC PATCH 03/15] powerpc/ftrace: Simplify function_graph support in ftrace.c Date: Wed, 7 Jun 2023 22:25:18 +0530 Message-Id: <27c83dad7d0f83f6b309602da45b30cf2e8db2ce.1686151854.git.naveen@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Since we now support DYNAMIC_FTRACE_WITH_ARGS across ppc32 and ppc64 ELFv2, we can simplify function_graph tracer support code in ftrace.c Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 64 ++++-------------------------- 1 file changed, 7 insertions(+), 57 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 81a121b56c4d7f..f117124c30325f 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -790,44 +790,10 @@ int __init ftrace_dyn_arch_init(void) #endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER - -extern void ftrace_graph_call(void); -extern void ftrace_graph_stub(void); - -static int ftrace_modify_ftrace_graph_caller(bool enable) +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs) { - unsigned long ip = (unsigned long)(&ftrace_graph_call); - unsigned long addr = (unsigned long)(&ftrace_graph_caller); - unsigned long stub = (unsigned long)(&ftrace_graph_stub); - ppc_inst_t old, new; - - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS)) - return 0; - - old = ftrace_call_replace(ip, enable ? stub : addr, 0); - new = ftrace_call_replace(ip, enable ? addr : stub, 0); - - return ftrace_modify_code(ip, old, new); -} - -int ftrace_enable_ftrace_graph_caller(void) -{ - return ftrace_modify_ftrace_graph_caller(true); -} - -int ftrace_disable_ftrace_graph_caller(void) -{ - return ftrace_modify_ftrace_graph_caller(false); -} - -/* - * Hook the return address and push it in the stack of return addrs - * in current thread info. Return the address we want to divert to. - */ -static unsigned long -__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp) -{ - unsigned long return_hooker; + unsigned long sp = fregs->regs.gpr[1]; int bit; if (unlikely(ftrace_graph_is_dead())) @@ -836,31 +802,15 @@ __prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp if (unlikely(atomic_read(¤t->tracing_graph_pause))) goto out; - bit = ftrace_test_recursion_trylock(ip, parent); + bit = ftrace_test_recursion_trylock(ip, parent_ip); if (bit < 0) goto out; - return_hooker = ppc_function_entry(return_to_handler); - - if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp)) - parent = return_hooker; + if (!function_graph_enter(parent_ip, ip, 0, (unsigned long *)sp)) + parent_ip = ppc_function_entry(return_to_handler); ftrace_test_recursion_unlock(bit); out: - return parent; + fregs->regs.link = parent_ip; } - -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS -void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct ftrace_regs *fregs) -{ - fregs->regs.link = __prepare_ftrace_return(parent_ip, ip, fregs->regs.gpr[1]); -} -#else -unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, - unsigned long sp) -{ - return __prepare_ftrace_return(parent, ip, sp); -} -#endif #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ From patchwork Wed Jun 7 16:55:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791845 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=Fwxl0tVK; 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bh=ogEUXT2uop1wwWimAziuOSqdGoByA/s+m4cCyc0kb0o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fwxl0tVKIXFPIvVpl5XOfAF8o/h69/nw/TgjKMgcACbUoyIMhxZHsYKcSgwK09vyr TO9ZF1NuDCnvg4/3eYfP5SPx8qjo+eyoboLap/UQH8wc2I51CM485Tb+NHU7pGYb23 omoVidWCvrAu5G4TwjbH0cm7rnAtj9itbTdtumUPTdMNL02y2eirdllv8Oy2rpxWG3 fAxNdELlXWKJ9cdLd2dRj7809hiTp0540095f2T4rcndenSNGFeAHO/cOu0SXA6Jou sa4IJzlQvvDsPBeXJV0RMOP+B6G+9azigrMw5VxEiBRMgBIoPkRpNZitEdsqvHRajH dQHrjig2iDGyg== From: Naveen N Rao To: Subject: [RFC PATCH 04/15] powerpc/ftrace: Use FTRACE_REGS_ADDR to identify the correct ftrace trampoline Date: Wed, 7 Jun 2023 22:25:19 +0530 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Instead of keying off DYNAMIC_FTRACE_WITH_REGS, use FTRACE_REGS_ADDR to identify the proper ftrace trampoline address to use. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index f117124c30325f..5aa36272617a03 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -745,14 +745,9 @@ int __init ftrace_dyn_arch_init(void) }; #endif - unsigned long addr; + unsigned long addr = FTRACE_REGS_ADDR; long reladdr; - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) - addr = ppc_global_function_entry((void *)ftrace_regs_caller); - else - addr = ppc_global_function_entry((void *)ftrace_caller); - if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { for (i = 0; i < 2; i++) { reladdr = addr - (unsigned long)tramp[i]; From patchwork Wed Jun 7 16:55:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791848 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=eDLhnbMx; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4Qbv1C34Mlz20Ty for ; Thu, 8 Jun 2023 03:07:59 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Qbv1C0kqDz3ffC for ; Thu, 8 Jun 2023 03:07:59 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=eDLhnbMx; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=eDLhnbMx; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Qbtrm0Svjz3dvv for ; Thu, 8 Jun 2023 03:00:40 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6938A60A49; Wed, 7 Jun 2023 17:00:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56552C433EF; Wed, 7 Jun 2023 17:00:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157235; bh=xbpmDG8w15nChKJFePzV+Lv8kheEm0YYcR+3RFIe2tk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eDLhnbMxJPhoweA97bFtniP8YMQOj2XDrSh0X+gY8RO0TK7VUM50/ai2Sbvxd5iWs erYlWsSHJDDc79qeRig6HrxkWguwd100bm4GAZaVbUDqD4XpNf0tIn5IKhXP3cCFIh jacAtEe440I7p0v+gbvu6jhekDjllkn1iIo1oKzwsnxK3DV/Bco7ST5MpNcxXuUAsx rBALjhsvnrkyoSzSst6YOa4plLNByT8ddunNWsOk+WJo8PPM2Q0Hm62JaA+g6ScKNM N8mGTDrLYaoYMBpMpiDVIlnCOBzSEwVwtGWRWZjyPYB9kTM3WhoINEaFtdxRrdj0jt zJ/0mAbnARHmA== From: Naveen N Rao To: Subject: [RFC PATCH 05/15] powerpc/ftrace: Extend ftrace support for large kernels to ppc32 Date: Wed, 7 Jun 2023 22:25:20 +0530 Message-Id: <4d64abc6b9237e2ea0425f86b4c44cf78ededdc3.1686151854.git.naveen@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Commit 67361cf8071286 ("powerpc/ftrace: Handle large kernel configs") added ftrace support for ppc64 kernel images with a text section larger than 32MB. The approach itself isn't specific to ppc64, so extend the same to also work on ppc32. While at it, reduce the space reserved for the stub from 64 bytes to 32 bytes since the different stub variants are all less than 8 instructions. To reduce use of #ifdef, a stub implementation is provided for kernel_toc_address() and -SZ_2G is cast to 'long long' to prevent errors on ppc32. Signed-off-by: Naveen N Rao --- arch/powerpc/include/asm/ftrace.h | 10 +++++-- arch/powerpc/include/asm/sections.h | 2 ++ arch/powerpc/kernel/trace/ftrace.c | 39 ++++++++++++++------------ arch/powerpc/kernel/trace/ftrace_low.S | 6 ++-- arch/powerpc/kernel/vmlinux.lds.S | 4 --- 5 files changed, 32 insertions(+), 29 deletions(-) diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 91c049d51d0e10..1a5d365523e160 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -124,15 +124,19 @@ static inline u8 this_cpu_get_ftrace_enabled(void) { return get_paca()->ftrace_enabled; } - -void ftrace_free_init_tramp(void); #else /* CONFIG_PPC64 */ static inline void this_cpu_disable_ftrace(void) { } static inline void this_cpu_enable_ftrace(void) { } static inline void this_cpu_set_ftrace_enabled(u8 ftrace_enabled) { } static inline u8 this_cpu_get_ftrace_enabled(void) { return 1; } -static inline void ftrace_free_init_tramp(void) { } #endif /* CONFIG_PPC64 */ + +#ifdef CONFIG_FUNCTION_TRACER +extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; +void ftrace_free_init_tramp(void); +#else +static inline void ftrace_free_init_tramp(void) { } +#endif #endif /* !__ASSEMBLY__ */ #endif /* _ASM_POWERPC_FTRACE */ diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h index 4e1f548c8d373d..ea26665f82cfc8 100644 --- a/arch/powerpc/include/asm/sections.h +++ b/arch/powerpc/include/asm/sections.h @@ -74,6 +74,8 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end) (unsigned long)_stext < end; } +#else +static inline unsigned long kernel_toc_addr(void) { BUILD_BUG(); return -1UL; } #endif #endif /* __KERNEL__ */ diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 5aa36272617a03..913c7aa63d3fa3 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -707,11 +707,6 @@ void arch_ftrace_update_code(int command) ftrace_modify_all_code(command); } -#ifdef CONFIG_PPC64 -#define PACATOC offsetof(struct paca_struct, kernel_toc) - -extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; - void ftrace_free_init_tramp(void) { int i; @@ -725,28 +720,30 @@ void ftrace_free_init_tramp(void) int __init ftrace_dyn_arch_init(void) { - int i; unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init }; -#ifdef CONFIG_PPC_KERNEL_PCREL + unsigned long addr = FTRACE_REGS_ADDR; + long reladdr; + int i; u32 stub_insns[] = { +#ifdef CONFIG_PPC_KERNEL_PCREL /* pla r12,addr */ PPC_PREFIX_MLS | __PPC_PRFX_R(1), PPC_INST_PADDI | ___PPC_RT(_R12), PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR() - }; -#else - u32 stub_insns[] = { - PPC_RAW_LD(_R12, _R13, PACATOC), +#elif defined(CONFIG_PPC64) + PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)), PPC_RAW_ADDIS(_R12, _R12, 0), PPC_RAW_ADDI(_R12, _R12, 0), PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR() - }; +#else + PPC_RAW_LIS(_R12, 0), + PPC_RAW_ADDI(_R12, _R12, 0), + PPC_RAW_MTCTR(_R12), + PPC_RAW_BCTR() #endif - - unsigned long addr = FTRACE_REGS_ADDR; - long reladdr; + }; if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { for (i = 0; i < 2; i++) { @@ -763,10 +760,10 @@ int __init ftrace_dyn_arch_init(void) tramp[i][1] |= IMM_L(reladdr); add_ftrace_tramp((unsigned long)tramp[i]); } - } else { + } else if (IS_ENABLED(CONFIG_PPC64)) { reladdr = addr - kernel_toc_addr(); - if (reladdr >= (long)SZ_2G || reladdr < -(long)SZ_2G) { + if (reladdr >= (long)SZ_2G || reladdr < -(long long)SZ_2G) { pr_err("Address of %ps out of range of kernel_toc.\n", (void *)addr); return -1; @@ -778,11 +775,17 @@ int __init ftrace_dyn_arch_init(void) tramp[i][2] |= PPC_LO(reladdr); add_ftrace_tramp((unsigned long)tramp[i]); } + } else { + for (i = 0; i < 2; i++) { + memcpy(tramp[i], stub_insns, sizeof(stub_insns)); + tramp[i][0] |= PPC_HA(addr); + tramp[i][1] |= PPC_LO(addr); + add_ftrace_tramp((unsigned long)tramp[i]); + } } return 0; } -#endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, diff --git a/arch/powerpc/kernel/trace/ftrace_low.S b/arch/powerpc/kernel/trace/ftrace_low.S index 294d1e05958aae..2fc7dd0a5ae968 100644 --- a/arch/powerpc/kernel/trace/ftrace_low.S +++ b/arch/powerpc/kernel/trace/ftrace_low.S @@ -10,19 +10,17 @@ #include #include -#ifdef CONFIG_PPC64 .pushsection ".tramp.ftrace.text","aw",@progbits; .globl ftrace_tramp_text ftrace_tramp_text: - .space 64 + .space 32 .popsection .pushsection ".tramp.ftrace.init","aw",@progbits; .globl ftrace_tramp_init ftrace_tramp_init: - .space 64 + .space 32 .popsection -#endif _GLOBAL(mcount) _GLOBAL(_mcount) diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 13614f0b269cf4..1c5970df323366 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -107,9 +107,7 @@ SECTIONS #endif /* careful! __ftr_alt_* sections need to be close to .text */ *(.text.hot .text.hot.* TEXT_MAIN .text.fixup .text.unlikely .text.unlikely.* .fixup __ftr_alt_* .ref.text); -#ifdef CONFIG_PPC64 *(.tramp.ftrace.text); -#endif NOINSTR_TEXT SCHED_TEXT LOCK_TEXT @@ -276,9 +274,7 @@ SECTIONS */ . = ALIGN(PAGE_SIZE); _einittext = .; -#ifdef CONFIG_PPC64 *(.tramp.ftrace.init); -#endif } :text /* .exit.text is discarded at runtime, not link time, From patchwork Wed Jun 7 16:55:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791849 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=BhisoVWh; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4Qbv2849xGz20Ty for ; Thu, 8 Jun 2023 03:08:48 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Qbv2759JMz3fvb for ; Thu, 8 Jun 2023 03:08:47 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=BhisoVWh; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=BhisoVWh; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Qbtrq0FvQz3dy8 for ; Thu, 8 Jun 2023 03:00:43 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 627FD60B34; Wed, 7 Jun 2023 17:00:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51021C433D2; Wed, 7 Jun 2023 17:00:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157240; bh=+h+3LyPm6CZYkFnOmOUKuPI8mQbyKGMHvHU2h6EHRe4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BhisoVWhHXhGg59cm/rJ6XZDFngs1MTgL9d8AkLQXXTyQedLqb8q32mvTEKpFzzvd Y3RaSoAP14oqHyTFToB95vT2Hq9RqHRArb5r8wny6s7RMmvR/N+peVsMvRGfBTgWrf 5WMj/d1n+X7qVQLz8qX+dRjswM2ZkR7aAeFCp5w92w4M2sa/mSuBT+VBx4gREFOLa0 tWrYhsSVDVRnPLxkjEb1pZxd3TdMtT1Zq7Y6b9D507NVT2n4A3Yyl2rI57zsn8VutH EX8nnp49GKhP0myXIwuW8yyPSpCUUYpQ89Dnq8ExL4DkQuLwylv7+rZp8BVggCMj1l lgTJZTFfEGT4A== From: Naveen N Rao To: Subject: [RFC PATCH 06/15] powerpc/ftrace: Consolidate ftrace support into fewer files Date: Wed, 7 Jun 2023 22:25:21 +0530 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" ftrace_low.S has just the _mcount stub and return_to_handler(). Merge this back into ftrace_mprofile.S and ftrace_64_pg.S to keep all ftrace code together, and to allow those to evolve independently. ftrace_mprofile.S is also not an entirely accurate name since this also holds ppc32 code. This will be all the more incorrect once support for -fpatchable-function-entry is added. Rename files here to more accurately describe the code: - ftrace_mprofile.S is renamed to ftrace_entry.S - ftrace_pg.c is renamed to ftrace_64_pg.c - ftrace_64_pg.S is rename to ftrace_64_pg_entry.S Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/Makefile | 17 +++-- arch/powerpc/kernel/trace/ftrace_64_pg.S | 67 ------------------- .../trace/{ftrace_pg.c => ftrace_64_pg.c} | 0 .../{ftrace_low.S => ftrace_64_pg_entry.S} | 58 +++++++++++++++- .../{ftrace_mprofile.S => ftrace_entry.S} | 65 ++++++++++++++++++ 5 files changed, 130 insertions(+), 77 deletions(-) delete mode 100644 arch/powerpc/kernel/trace/ftrace_64_pg.S rename arch/powerpc/kernel/trace/{ftrace_pg.c => ftrace_64_pg.c} (100%) rename arch/powerpc/kernel/trace/{ftrace_low.S => ftrace_64_pg_entry.S} (55%) rename arch/powerpc/kernel/trace/{ftrace_mprofile.S => ftrace_entry.S} (83%) diff --git a/arch/powerpc/kernel/trace/Makefile b/arch/powerpc/kernel/trace/Makefile index 342a2d1ae86cd0..125f4ca588b98a 100644 --- a/arch/powerpc/kernel/trace/Makefile +++ b/arch/powerpc/kernel/trace/Makefile @@ -6,16 +6,15 @@ ifdef CONFIG_FUNCTION_TRACER # do not trace tracer code CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) -CFLAGS_REMOVE_ftrace_pg.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_ftrace_64_pg.o = $(CC_FLAGS_FTRACE) endif -obj32-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o ftrace.o +obj32-$(CONFIG_FUNCTION_TRACER) += ftrace.o ftrace_entry.o ifdef CONFIG_MPROFILE_KERNEL -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o ftrace.o +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace.o ftrace_entry.o else -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o ftrace_pg.o +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o ftrace_64_pg_entry.o endif -obj-$(CONFIG_FUNCTION_TRACER) += ftrace_low.o obj-$(CONFIG_TRACING) += trace_clock.o obj-$(CONFIG_PPC64) += $(obj64-y) @@ -26,7 +25,7 @@ GCOV_PROFILE_ftrace.o := n KCOV_INSTRUMENT_ftrace.o := n KCSAN_SANITIZE_ftrace.o := n UBSAN_SANITIZE_ftrace.o := n -GCOV_PROFILE_ftrace_pg.o := n -KCOV_INSTRUMENT_ftrace_pg.o := n -KCSAN_SANITIZE_ftrace_pg.o := n -UBSAN_SANITIZE_ftrace_pg.o := n +GCOV_PROFILE_ftrace_64_pg.o := n +KCOV_INSTRUMENT_ftrace_64_pg.o := n +KCSAN_SANITIZE_ftrace_64_pg.o := n +UBSAN_SANITIZE_ftrace_64_pg.o := n diff --git a/arch/powerpc/kernel/trace/ftrace_64_pg.S b/arch/powerpc/kernel/trace/ftrace_64_pg.S deleted file mode 100644 index 6708e24db0aba8..00000000000000 --- a/arch/powerpc/kernel/trace/ftrace_64_pg.S +++ /dev/null @@ -1,67 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-or-later */ -/* - * Split from ftrace_64.S - */ - -#include -#include -#include -#include -#include -#include - -_GLOBAL_TOC(ftrace_caller) - lbz r3, PACA_FTRACE_ENABLED(r13) - cmpdi r3, 0 - beqlr - - /* Taken from output of objdump from lib64/glibc */ - mflr r3 - ld r11, 0(r1) - stdu r1, -112(r1) - std r3, 128(r1) - ld r4, 16(r11) - subi r3, r3, MCOUNT_INSN_SIZE -.globl ftrace_call -ftrace_call: - bl ftrace_stub - nop -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -.globl ftrace_graph_call -ftrace_graph_call: - b ftrace_graph_stub -_GLOBAL(ftrace_graph_stub) -#endif - ld r0, 128(r1) - mtlr r0 - addi r1, r1, 112 - -_GLOBAL(ftrace_stub) - blr - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -_GLOBAL(ftrace_graph_caller) - addi r5, r1, 112 - /* load r4 with local address */ - ld r4, 128(r1) - subi r4, r4, MCOUNT_INSN_SIZE - - /* Grab the LR out of the caller stack frame */ - ld r11, 112(r1) - ld r3, 16(r11) - - bl prepare_ftrace_return - nop - - /* - * prepare_ftrace_return gives us the address we divert to. - * Change the LR in the callers stack frame to this. - */ - ld r11, 112(r1) - std r3, 16(r11) - - ld r0, 128(r1) - mtlr r0 - addi r1, r1, 112 - blr -#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/arch/powerpc/kernel/trace/ftrace_pg.c b/arch/powerpc/kernel/trace/ftrace_64_pg.c similarity index 100% rename from arch/powerpc/kernel/trace/ftrace_pg.c rename to arch/powerpc/kernel/trace/ftrace_64_pg.c diff --git a/arch/powerpc/kernel/trace/ftrace_low.S b/arch/powerpc/kernel/trace/ftrace_64_pg_entry.S similarity index 55% rename from arch/powerpc/kernel/trace/ftrace_low.S rename to arch/powerpc/kernel/trace/ftrace_64_pg_entry.S index 2fc7dd0a5ae968..81dbaf70b1513a 100644 --- a/arch/powerpc/kernel/trace/ftrace_low.S +++ b/arch/powerpc/kernel/trace/ftrace_64_pg_entry.S @@ -1,6 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0-or-later */ /* - * Split from entry_64.S + * Split from ftrace_64.S */ #include @@ -10,6 +10,62 @@ #include #include +_GLOBAL_TOC(ftrace_caller) + lbz r3, PACA_FTRACE_ENABLED(r13) + cmpdi r3, 0 + beqlr + + /* Taken from output of objdump from lib64/glibc */ + mflr r3 + ld r11, 0(r1) + stdu r1, -112(r1) + std r3, 128(r1) + ld r4, 16(r11) + subi r3, r3, MCOUNT_INSN_SIZE +.globl ftrace_call +ftrace_call: + bl ftrace_stub + nop +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +.globl ftrace_graph_call +ftrace_graph_call: + b ftrace_graph_stub +_GLOBAL(ftrace_graph_stub) +#endif + ld r0, 128(r1) + mtlr r0 + addi r1, r1, 112 + +_GLOBAL(ftrace_stub) + blr + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +_GLOBAL(ftrace_graph_caller) + addi r5, r1, 112 + /* load r4 with local address */ + ld r4, 128(r1) + subi r4, r4, MCOUNT_INSN_SIZE + + /* Grab the LR out of the caller stack frame */ + ld r11, 112(r1) + ld r3, 16(r11) + + bl prepare_ftrace_return + nop + + /* + * prepare_ftrace_return gives us the address we divert to. + * Change the LR in the callers stack frame to this. + */ + ld r11, 112(r1) + std r3, 16(r11) + + ld r0, 128(r1) + mtlr r0 + addi r1, r1, 112 + blr +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + .pushsection ".tramp.ftrace.text","aw",@progbits; .globl ftrace_tramp_text ftrace_tramp_text: diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_entry.S similarity index 83% rename from arch/powerpc/kernel/trace/ftrace_mprofile.S rename to arch/powerpc/kernel/trace/ftrace_entry.S index ffb1db38684998..e8339706e735b1 100644 --- a/arch/powerpc/kernel/trace/ftrace_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_entry.S @@ -249,3 +249,68 @@ livepatch_handler: /* Return to original caller of live patched function */ blr #endif /* CONFIG_LIVEPATCH */ + +_GLOBAL(mcount) +_GLOBAL(_mcount) +EXPORT_SYMBOL(_mcount) + mflr r12 + mtctr r12 + mtlr r0 + bctr + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +_GLOBAL(return_to_handler) + /* need to save return values */ +#ifdef CONFIG_PPC64 + std r4, -32(r1) + std r3, -24(r1) + /* save TOC */ + std r2, -16(r1) + std r31, -8(r1) + mr r31, r1 + stdu r1, -112(r1) + + /* + * We might be called from a module. + * Switch to our TOC to run inside the core kernel. + */ + LOAD_PACA_TOC() +#else + stwu r1, -16(r1) + stw r3, 8(r1) + stw r4, 12(r1) +#endif + + bl ftrace_return_to_handler + nop + + /* return value has real return address */ + mtlr r3 + +#ifdef CONFIG_PPC64 + ld r1, 0(r1) + ld r4, -32(r1) + ld r3, -24(r1) + ld r2, -16(r1) + ld r31, -8(r1) +#else + lwz r3, 8(r1) + lwz r4, 12(r1) + addi r1, r1, 16 +#endif + + /* Jump back to real return address */ + blr +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +.pushsection ".tramp.ftrace.text","aw",@progbits; +.globl ftrace_tramp_text +ftrace_tramp_text: + .space 32 +.popsection + +.pushsection ".tramp.ftrace.init","aw",@progbits; +.globl ftrace_tramp_init +ftrace_tramp_init: + .space 32 +.popsection From patchwork Wed Jun 7 16:55:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791850 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; 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ESMTPSA id 97E43C433EF; Wed, 7 Jun 2023 17:00:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157245; bh=8JeQh63fPatsalzj0Vl6bvA1m4bFoaGQC3L7k3yskE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pv+UP5EKII20qR7tpGpXG2N8tDCpVnw/YmhKF8rtvNhq3Lbg/A2r2Lr4wfHs4pW12 7WVCCi3woau2AzQnmBTDa5JUkn5g0JEckVpPtxdZloc5B/DjjBzSd7mpsUf48NBfOi mDqoyHXyjNmCxdMsg1lAP+VOQga9bmd+KH/57YsRgjmaBLcmh8IOWzUxXnNILNW9Yu +ZOdAP0ES2t8zbvDhgXSMrfGCe/sgSDTDkYHzdW6MSX8nwtRImEjR6fe8BJ8eG4aZx CXo7bU5uRLcjuUVQPElE66rhB83keGmb/kcurLVx7b1TFleNsAAOgW3y4MCk2xkOLl UkldivOepDv6Q== From: Naveen N Rao To: Subject: [RFC PATCH 07/15] powerpc/ftrace: Refactor ftrace_modify_code() Date: Wed, 7 Jun 2023 22:25:22 +0530 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Split up ftrace_modify_code() into a few helpers for future use. Also update error messages accordingly. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 51 +++++++++++++++++------------- 1 file changed, 29 insertions(+), 22 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 913c7aa63d3fa3..ef4e49c2c37781 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -50,32 +50,39 @@ ftrace_call_replace(unsigned long ip, unsigned long addr, int link) return op; } -static inline int -ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) +static inline int ftrace_read_inst(unsigned long ip, ppc_inst_t *op) { - ppc_inst_t replaced; - - /* - * Note: - * We are paranoid about modifying text, as if a bug was to happen, it - * could cause us to read or write to someplace that could cause harm. - * Carefully read and modify the code with probe_kernel_*(), and make - * sure what we read is what we expected it to be before modifying it. - */ - - /* read the text we want to modify */ - if (copy_inst_from_kernel_nofault(&replaced, (void *)ip)) + if (copy_inst_from_kernel_nofault(op, (void *)ip)) { + pr_err("0x%lx: fetching instruction failed\n", ip); return -EFAULT; - - /* Make sure it is what we expect it to be */ - if (!ppc_inst_equal(replaced, old)) { - pr_err("%p: replaced (%08lx) != old (%08lx)", (void *)ip, - ppc_inst_as_ulong(replaced), ppc_inst_as_ulong(old)); - return -EINVAL; } - /* replace the text with the new text */ - return patch_instruction((u32 *)ip, new); + return 0; +} + +static inline int ftrace_validate_inst(unsigned long ip, ppc_inst_t inst) +{ + ppc_inst_t op; + int ret; + + ret = ftrace_read_inst(ip, &op); + if (!ret && !ppc_inst_equal(op, inst)) { + pr_err("0x%lx: expected (%08lx) != found (%08lx)\n", + ip, ppc_inst_as_ulong(inst), ppc_inst_as_ulong(op)); + ret = -EINVAL; + } + + return ret; +} + +static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) +{ + int ret = ftrace_validate_inst(ip, old); + + if (!ret) + ret = patch_instruction((u32 *)ip, new); + + return ret; } /* From patchwork Wed Jun 7 16:55:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791852 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; 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dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=Ot2ME/2A; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4641:c500::1; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=Ot2ME/2A; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Qbts01l0Gz3f60 for ; Thu, 8 Jun 2023 03:00:51 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 23EFF60B60; Wed, 7 Jun 2023 17:00:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1342EC433D2; Wed, 7 Jun 2023 17:00:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157249; bh=jk9z1qfTbnJ4M50k9sUONn0cX2iepmGzBY8gg5oa7Ew=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ot2ME/2AMYWLrdy9cJM4a76yEX5gC4d8TN7jo5VxfG7mEeWsMhb3BwyGJFlryg4dP PvyFk9rfAuT86H4zNPvJMNlO6K6TUi51VK2Glul8dmGzOZubQEXtYUmLBNC3IxSwcm vsHYewFrchMP0eUn/ekR3ZAyJJkCS6agXogJNuOa1ujxfGDEJ8T4T+NpwH30dOXVOT Tj1lUmdkPiIdTjXuisDm3gXXF94XSoVyWYpv/okLtdwLBwUhh0K0w2OiCwO58eZBlY VXfNwsuD9Qfp05PiklmCKrSuySYjtAuX4FbpVfCxyYCmWLPHkr3BA/zFKx5NGiYZz0 FGJgeG68nNh9g== From: Naveen N Rao To: Subject: [RFC PATCH 08/15] powerpc/ftrace: Stop re-purposing linker generated long branches for ftrace Date: Wed, 7 Jun 2023 22:25:23 +0530 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Commit 67361cf8071286 ("powerpc/ftrace: Handle large kernel configs") added ftrace support for ppc64 kernel images with a text section larger than 32MB. The patch did two things: 1. Add stubs at the end of .text to branch into ftrace_[regs_]caller for functions that were out of branch range. 2. Re-purpose linker-generated long branches to _mcount to instead branch to ftrace_[regs_]caller. Before that, we only supported kernel .text up to ~32MB. With the above, we now support up to ~96MB: - The first 32MB of kernel text can branch directly into ftrace_[regs_]caller since that symbol is usually at the beginning. - The modified long_branch from (2) above is used by the next 32MB of kernel text. - The next 32MB of kernel text can use the stub at the end of text to branch back to ftrace_[regs_]caller. While re-purposing the long branch works in practice, it still restricts ftrace to kernel text up to ~96MB. The stub at the end of kernel text from (1) already enables us to extend ftrace support for kernel text up to 64MB, which fulfils the original requirement. Further, once we switch to -fpatchable-function-entry, there will not be a long branch that we can use. Stop re-purposing the linker-generated long branches for ftrace to simplify the code. If there are good reasons to support ftrace on kernels beyond 64MB, we can consider adding support by using -fpatchable-function-entry. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 110 +++++------------------------ 1 file changed, 17 insertions(+), 93 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index ef4e49c2c37781..278bf8e52b6e89 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -28,13 +28,7 @@ #include #include -/* - * We generally only have a single long_branch tramp and at most 2 or 3 plt - * tramps generated. But, we don't use the plt tramps currently. We also allot - * 2 tramps after .text and .init.text. So, we only end up with around 3 usable - * tramps in total. Set aside 8 just to be sure. - */ -#define NUM_FTRACE_TRAMPS 8 +#define NUM_FTRACE_TRAMPS 2 static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; static ppc_inst_t @@ -100,11 +94,6 @@ static int is_bl_op(ppc_inst_t op) return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0); } -static int is_b_op(ppc_inst_t op) -{ - return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BRANCH(0); -} - static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) { int offset; @@ -227,11 +216,7 @@ static unsigned long find_ftrace_tramp(unsigned long ip) { int i; - /* - * We have the compiler generated long_branch tramps at the end - * and we prefer those - */ - for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--) + for (i = 0; i < NUM_FTRACE_TRAMPS; i++) if (!ftrace_tramps[i]) continue; else if (is_offset_in_branch_range(ftrace_tramps[i] - ip)) @@ -240,75 +225,6 @@ static unsigned long find_ftrace_tramp(unsigned long ip) return 0; } -static int add_ftrace_tramp(unsigned long tramp) -{ - int i; - - for (i = 0; i < NUM_FTRACE_TRAMPS; i++) - if (!ftrace_tramps[i]) { - ftrace_tramps[i] = tramp; - return 0; - } - - return -1; -} - -/* - * If this is a compiler generated long_branch trampoline (essentially, a - * trampoline that has a branch to _mcount()), we re-write the branch to - * instead go to ftrace_[regs_]caller() and note down the location of this - * trampoline. - */ -static int setup_mcount_compiler_tramp(unsigned long tramp) -{ - int i; - ppc_inst_t op; - unsigned long ptr; - - /* Is this a known long jump tramp? */ - for (i = 0; i < NUM_FTRACE_TRAMPS; i++) - if (ftrace_tramps[i] == tramp) - return 0; - - /* New trampoline -- read where this goes */ - if (copy_inst_from_kernel_nofault(&op, (void *)tramp)) { - pr_debug("Fetching opcode failed.\n"); - return -1; - } - - /* Is this a 24 bit branch? */ - if (!is_b_op(op)) { - pr_debug("Trampoline is not a long branch tramp.\n"); - return -1; - } - - /* lets find where the pointer goes */ - ptr = find_bl_target(tramp, op); - - if (ptr != ppc_global_function_entry((void *)_mcount)) { - pr_debug("Trampoline target %p is not _mcount\n", (void *)ptr); - return -1; - } - - /* Let's re-write the tramp to go to ftrace_[regs_]caller */ - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) - ptr = ppc_global_function_entry((void *)ftrace_regs_caller); - else - ptr = ppc_global_function_entry((void *)ftrace_caller); - - if (patch_branch((u32 *)tramp, ptr, 0)) { - pr_debug("REL24 out of range!\n"); - return -1; - } - - if (add_ftrace_tramp(tramp)) { - pr_debug("No tramp locations left\n"); - return -1; - } - - return 0; -} - static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) { unsigned long tramp, ip = rec->ip; @@ -331,13 +247,10 @@ static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) pr_devel("ip:%lx jumps to %lx", ip, tramp); - if (setup_mcount_compiler_tramp(tramp)) { - /* Are other trampolines reachable? */ - if (!find_ftrace_tramp(ip)) { - pr_err("No ftrace trampolines reachable from %ps\n", - (void *)ip); - return -EINVAL; - } + /* Are ftrace trampolines reachable? */ + if (!find_ftrace_tramp(ip)) { + pr_err("No ftrace trampolines reachable from %ps\n", (void *)ip); + return -EINVAL; } if (patch_instruction((u32 *)ip, ppc_inst(PPC_RAW_NOP()))) { @@ -725,6 +638,17 @@ void ftrace_free_init_tramp(void) } } +static void __init add_ftrace_tramp(unsigned long tramp) +{ + int i; + + for (i = 0; i < NUM_FTRACE_TRAMPS; i++) + if (!ftrace_tramps[i]) { + ftrace_tramps[i] = tramp; + return; + } +} + int __init ftrace_dyn_arch_init(void) { unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init }; From patchwork Wed Jun 7 16:55:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791853 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=tHobEMxg; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4Qbv5673h6z20WP for ; Thu, 8 Jun 2023 03:11:22 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Qbv5661Qlz3gNS for ; Thu, 8 Jun 2023 03:11:22 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=tHobEMxg; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4641:c500::1; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=tHobEMxg; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Qbts42sSLz3f7F for ; Thu, 8 Jun 2023 03:00:56 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B60CB60B34; Wed, 7 Jun 2023 17:00:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A00E6C433EF; Wed, 7 Jun 2023 17:00:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157254; bh=ENTL9jz4xseQBAYNa1hOUdTwA84v+/79JmfAzV56XLE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tHobEMxg5qYowCY+M6cFBe36fnLNywgmzb/mqbAQgj/Bok366t8bmC/mqJ+OYA1pb aTg1QQVGfRpEXslWK1+Pf/bFZ1zvdG5GOZ71YQClzW1vWIl8M+zZ4e/YFO4nhsEOef xlEt40BLxDWXaThpdcFrfGozr28MdfQsIvP7p9wi/WZK6tUXR5pV8XioyjFQ21VAMq 214JoFekM0O0jZMKx+izsQMcp1270qikxLBjhQYoACEmpiIxOfCFZOQcMrxJ5+cxVp XnUs0ZFivV/+DOOtlo17d6mJFeXEoW1SS0FE9EjcE6BGBlHACPnenyvfYM7KYMv2ze IqytCpvPjhC6w== From: Naveen N Rao To: Subject: [RFC PATCH 09/15] powerpc/ftrace: Add separate ftrace_init_nop() with additional validation Date: Wed, 7 Jun 2023 22:25:24 +0530 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Currently, we validate instructions around the ftrace location every time we have to enable/disable ftrace. Introduce ftrace_init_nop() to instead perform all the validation during ftrace initialization. This allows us to simply patch the necessary instructions during enabling/disabling ftrace. Signed-off-by: Naveen N Rao --- arch/powerpc/include/asm/ftrace.h | 6 +++ arch/powerpc/kernel/trace/ftrace.c | 71 ++++++++++++++++++++++++++++++ 2 files changed, 77 insertions(+) diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 1a5d365523e160..89fbae3caa1fc2 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -29,11 +29,17 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp); +struct module; +struct dyn_ftrace; struct dyn_arch_ftrace { struct module *mod; }; #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS +#define ftrace_need_init_nop() (true) +int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); +#define ftrace_init_nop ftrace_init_nop + struct ftrace_regs { struct pt_regs regs; }; diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 278bf8e52b6e89..c0d185742c23ca 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -31,6 +31,16 @@ #define NUM_FTRACE_TRAMPS 2 static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; +static ppc_inst_t ftrace_create_branch_inst(unsigned long ip, unsigned long addr, int link) +{ + ppc_inst_t op; + + WARN_ON(!is_offset_in_branch_range(addr - ip)); + create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0); + + return op; +} + static ppc_inst_t ftrace_call_replace(unsigned long ip, unsigned long addr, int link) { @@ -597,6 +607,67 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, } #endif +int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) +{ + unsigned long addr, ip = rec->ip; + ppc_inst_t old, new; + int ret = 0; + + /* Verify instructions surrounding the ftrace location */ + if (IS_ENABLED(CONFIG_PPC32)) { + /* Expected sequence: 'mflr r0', 'stw r0,4(r1)', 'bl _mcount' */ + ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0))); + if (!ret) + ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_STW(_R0, _R1, 4))); + } else if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) { + /* Expected sequence: 'mflr r0', ['std r0,16(r1)'], 'bl _mcount' */ + ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_MFLR(_R0))); + if (ret) { + ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_STD(_R0, _R1, 16))); + ret |= ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0))); + } + } else { + return -EINVAL; + } + + if (ret) + return ret; + + if (!core_kernel_text(ip)) { + if (!mod) { + pr_err("0x%lx: No module provided for non-kernel address\n", ip); + return -EFAULT; + } + rec->arch.mod = mod; + } + + /* Nop-out the ftrace location */ + new = ppc_inst(PPC_RAW_NOP()); + addr = MCOUNT_ADDR; + if (is_offset_in_branch_range(addr - ip)) { + /* Within range */ + old = ftrace_create_branch_inst(ip, addr, 1); + ret = ftrace_modify_code(ip, old, new); + } else if (core_kernel_text(ip) || (IS_ENABLED(CONFIG_MODULES) && mod)) { + /* + * We would be branching to a linker-generated stub, or to the module _mcount + * stub. Let's just confirm we have a 'bl' here. + */ + ret = ftrace_read_inst(ip, &old); + if (ret) + return ret; + if (!is_bl_op(old)) { + pr_err("0x%lx: expected (bl) != found (%08lx)\n", ip, ppc_inst_as_ulong(old)); + return -EINVAL; + } + ret = patch_instruction((u32 *)ip, new); + } else { + return -EINVAL; + } + + return ret; +} + int ftrace_update_ftrace_func(ftrace_func_t func) { unsigned long ip = (unsigned long)(&ftrace_call); From patchwork Wed Jun 7 16:55:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791854 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=IgsX+PBD; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4Qbv634x7tz20WP for ; Thu, 8 Jun 2023 03:12:11 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Qbv6337Wlz3g6V for ; Thu, 8 Jun 2023 03:12:11 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=IgsX+PBD; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4641:c500::1; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=IgsX+PBD; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Qbts90Mrhz3f83 for ; Thu, 8 Jun 2023 03:01:01 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0AE1360B60; Wed, 7 Jun 2023 17:00:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F02F3C433EF; Wed, 7 Jun 2023 17:00:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157258; bh=EFfqTnW40MKpWvvmP3J2uKvqmwkIHgzpxavKLWbX+44=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IgsX+PBDGt1W/M5NjhBliCD6TogcAQZdbkaHwVbXbvvJMefWIrpxOs0bsZMhJ68LO JqbMhA8ir4IXCqbkB2M3EA8sJZOSX0ukiRjUSnwQ46Cqt2nl8/SWv07TJliH3DpKTD S1BdgwtSr0/0CTzQsda5Lj59cA6PGsb8yi3fzHakKzVcA6vllR22NY0ISLELQphSx6 1iK2XudvQf7JFUkKjUotExKMeBJdwtDkHrCbBa7tZe48aXpsQjg1FHkx/Et1mNo77q nbsogPqvmyBfhOH44mm1ljY/UrNXPeaQjtPw37KBd9EgUsuYJ1roS0zK2o1RDilnz6 nCgtXEBeG/nUg== From: Naveen N Rao To: Subject: [RFC PATCH 10/15] powerpc/ftrace: Simplify ftrace_make_nop() Date: Wed, 7 Jun 2023 22:25:25 +0530 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Now that we validate the ftrace location during initialization in ftrace_init_nop(), we can simplify ftrace_make_nop() to patch-in the nop without worrying about the instructions surrounding the ftrace location. Note that we continue to ensure that we have a bl to ftrace_[regs_]caller at the ftrace location before nop-ing it out. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 220 +++++------------------------ 1 file changed, 32 insertions(+), 188 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index c0d185742c23ca..67773cd14da71a 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -116,112 +116,6 @@ static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) return ip + (long)offset; } -#ifdef CONFIG_MODULES -static int -__ftrace_make_nop(struct module *mod, - struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned long entry, ptr, tramp; - unsigned long ip = rec->ip; - ppc_inst_t op, pop; - - /* read where this goes */ - if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { - pr_err("Fetching opcode failed.\n"); - return -EFAULT; - } - - /* Make sure that this is still a 24bit jump */ - if (!is_bl_op(op)) { - pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); - return -EINVAL; - } - - /* lets find where the pointer goes */ - tramp = find_bl_target(ip, op); - - pr_devel("ip:%lx jumps to %lx", ip, tramp); - - if (module_trampoline_target(mod, tramp, &ptr)) { - pr_err("Failed to get trampoline target\n"); - return -EFAULT; - } - - pr_devel("trampoline target %lx", ptr); - - entry = ppc_global_function_entry((void *)addr); - /* This should match what was called */ - if (ptr != entry) { - pr_err("addr %lx does not match expected %lx\n", ptr, entry); - return -EINVAL; - } - - if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) { - if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 4))) { - pr_err("Fetching instruction at %lx failed.\n", ip - 4); - return -EFAULT; - } - - /* We expect either a mflr r0, or a std r0, LRSAVE(r1) */ - if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_MFLR(_R0))) && - !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) { - pr_err("Unexpected instruction %08lx around bl _mcount\n", - ppc_inst_as_ulong(op)); - return -EINVAL; - } - } else if (IS_ENABLED(CONFIG_PPC64)) { - /* - * Check what is in the next instruction. We can see ld r2,40(r1), but - * on first pass after boot we will see mflr r0. - */ - if (copy_inst_from_kernel_nofault(&op, (void *)(ip + 4))) { - pr_err("Fetching op failed.\n"); - return -EFAULT; - } - - if (!ppc_inst_equal(op, ppc_inst(PPC_INST_LD_TOC))) { - pr_err("Expected %08lx found %08lx\n", PPC_INST_LD_TOC, - ppc_inst_as_ulong(op)); - return -EINVAL; - } - } - - /* - * When using -mprofile-kernel or PPC32 there is no load to jump over. - * - * Otherwise our original call site looks like: - * - * bl - * ld r2,XX(r1) - * - * Milton Miller pointed out that we can not simply nop the branch. - * If a task was preempted when calling a trace function, the nops - * will remove the way to restore the TOC in r2 and the r2 TOC will - * get corrupted. - * - * Use a b +8 to jump over the load. - * XXX: could make PCREL depend on MPROFILE_KERNEL - * XXX: check PCREL && MPROFILE_KERNEL calling sequence - */ - if (IS_ENABLED(CONFIG_MPROFILE_KERNEL) || IS_ENABLED(CONFIG_PPC32)) - pop = ppc_inst(PPC_RAW_NOP()); - else - pop = ppc_inst(PPC_RAW_BRANCH(8)); /* b +8 */ - - if (patch_instruction((u32 *)ip, pop)) { - pr_err("Patching NOP failed.\n"); - return -EPERM; - } - - return 0; -} -#else -static int __ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) -{ - return 0; -} -#endif /* CONFIG_MODULES */ - static unsigned long find_ftrace_tramp(unsigned long ip) { int i; @@ -235,88 +129,6 @@ static unsigned long find_ftrace_tramp(unsigned long ip) return 0; } -static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned long tramp, ip = rec->ip; - ppc_inst_t op; - - /* Read where this goes */ - if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { - pr_err("Fetching opcode failed.\n"); - return -EFAULT; - } - - /* Make sure that this is still a 24bit jump */ - if (!is_bl_op(op)) { - pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); - return -EINVAL; - } - - /* Let's find where the pointer goes */ - tramp = find_bl_target(ip, op); - - pr_devel("ip:%lx jumps to %lx", ip, tramp); - - /* Are ftrace trampolines reachable? */ - if (!find_ftrace_tramp(ip)) { - pr_err("No ftrace trampolines reachable from %ps\n", (void *)ip); - return -EINVAL; - } - - if (patch_instruction((u32 *)ip, ppc_inst(PPC_RAW_NOP()))) { - pr_err("Patching NOP failed.\n"); - return -EPERM; - } - - return 0; -} - -int ftrace_make_nop(struct module *mod, - struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned long ip = rec->ip; - ppc_inst_t old, new; - - /* - * If the calling address is more that 24 bits away, - * then we had to use a trampoline to make the call. - * Otherwise just update the call site. - */ - if (test_24bit_addr(ip, addr)) { - /* within range */ - old = ftrace_call_replace(ip, addr, 1); - new = ppc_inst(PPC_RAW_NOP()); - return ftrace_modify_code(ip, old, new); - } else if (core_kernel_text(ip)) { - return __ftrace_make_nop_kernel(rec, addr); - } else if (!IS_ENABLED(CONFIG_MODULES)) { - return -EINVAL; - } - - /* - * Out of range jumps are called from modules. - * We should either already have a pointer to the module - * or it has been passed in. - */ - if (!rec->arch.mod) { - if (!mod) { - pr_err("No module loaded addr=%lx\n", addr); - return -EFAULT; - } - rec->arch.mod = mod; - } else if (mod) { - if (mod != rec->arch.mod) { - pr_err("Record mod %p not equal to passed in mod %p\n", - rec->arch.mod, mod); - return -EINVAL; - } - /* nothing to do if mod == rec->arch.mod */ - } else - mod = rec->arch.mod; - - return __ftrace_make_nop(mod, rec, addr); -} - #ifdef CONFIG_MODULES /* * Examine the existing instructions for __ftrace_make_call. @@ -607,6 +419,38 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, } #endif +int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned long tramp, ip = rec->ip; + ppc_inst_t old, new; + + /* Nop-out the ftrace location */ + new = ppc_inst(PPC_RAW_NOP()); + if (is_offset_in_branch_range(addr - ip)) { + /* Within range */ + old = ftrace_create_branch_inst(ip, addr, 1); + return ftrace_modify_code(ip, old, new); + } else if (core_kernel_text(ip)) { + /* We would be branching to one of our ftrace tramps */ + tramp = find_ftrace_tramp(ip); + if (!tramp) { + pr_err("0x%lx: No ftrace trampolines reachable\n", ip); + return -EINVAL; + } + old = ftrace_create_branch_inst(ip, tramp, 1); + return ftrace_modify_code(ip, old, new); + } else if (IS_ENABLED(CONFIG_MODULES)) { + /* Module code would be going to one of the module stubs */ + if (!mod) + mod = rec->arch.mod; + tramp = (addr == (unsigned long)ftrace_caller ? mod->arch.tramp : mod->arch.tramp_regs); + old = ftrace_create_branch_inst(ip, tramp, 1); + return ftrace_modify_code(ip, old, new); + } + + return -EINVAL; +} + int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { unsigned long addr, ip = rec->ip; From patchwork Wed Jun 7 16:55:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791838 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=nQgX/P16; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4QbtsP115xz20Q8 for ; Thu, 8 Jun 2023 03:01:13 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4QbtsP07Tjz3dtF for ; Thu, 8 Jun 2023 03:01:13 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=nQgX/P16; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4641:c500::1; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=nQgX/P16; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Qbtr44Wg0z3dtM for ; Thu, 8 Jun 2023 03:00:04 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A8CE964017; Wed, 7 Jun 2023 17:00:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 975ECC433D2; Wed, 7 Jun 2023 16:59:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157199; bh=elimukr1tAjj5cZi3vE0CMCZ4dYVSpWrsdSSpurSXXw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nQgX/P16vhzJFYo4YXrCOCGM81YTv9FbQzUZpR8ie/NIYqMhIENWLeRyhnSwey9+O sdoiJq7dGcN6JheDcav+eAbx9qq+pAdMUML6v64jmLhtJsBhC+U/9GnyjMbLMG1kfU jegZGvam8F7jCa5U4H82KmjQ5BdsANd2zRLqLUtArapjP/ziWKf6Hk8UqFtQQDq3UI a7DsLaJEEZDnKnwi9XslZaIVPiTNveFVx28hUpoDNlnI8FVQiJ246QSg1IF035iQ2U /K7uZb5a7xn1ZGFe899pa0eCFVJIaHq6uUoDKXzM/VqDkU6zO/Ak+9qsKVA+WGr2np ZWH8+jMPuGsFw== From: Naveen N Rao To: Subject: [RFC PATCH 11/15] powerpc/ftrace: Simplify ftrace_make_call() Date: Wed, 7 Jun 2023 22:25:26 +0530 Message-Id: <401740584309ef3498a166e01dd928546df2133f.1686151854.git.naveen@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Now that we validate the ftrace location during initialization in ftrace_init_nop(), we can simplify ftrace_make_call() to replace the nop without worrying about the instructions surrounding the ftrace location. Note that we continue to ensure that we have a nop at the ftrace location before patching it. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 187 +++++------------------------ 1 file changed, 31 insertions(+), 156 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 67773cd14da71a..8d5d91b8ae85a0 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -129,162 +129,6 @@ static unsigned long find_ftrace_tramp(unsigned long ip) return 0; } -#ifdef CONFIG_MODULES -/* - * Examine the existing instructions for __ftrace_make_call. - * They should effectively be a NOP, and follow formal constraints, - * depending on the ABI. Return false if they don't. - */ -static bool expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1) -{ - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) - return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())); - else - return ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) && - ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC)); -} - -static int -__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) -{ - ppc_inst_t op[2]; - void *ip = (void *)rec->ip; - unsigned long entry, ptr, tramp; - struct module *mod = rec->arch.mod; - - /* read where this goes */ - if (copy_inst_from_kernel_nofault(op, ip)) - return -EFAULT; - - if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && - copy_inst_from_kernel_nofault(op + 1, ip + 4)) - return -EFAULT; - - if (!expected_nop_sequence(ip, op[0], op[1])) { - pr_err("Unexpected call sequence at %p: %08lx %08lx\n", ip, - ppc_inst_as_ulong(op[0]), ppc_inst_as_ulong(op[1])); - return -EINVAL; - } - - /* If we never set up ftrace trampoline(s), then bail */ - if (!mod->arch.tramp || - (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !mod->arch.tramp_regs)) { - pr_err("No ftrace trampoline\n"); - return -EINVAL; - } - - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && rec->flags & FTRACE_FL_REGS) - tramp = mod->arch.tramp_regs; - else - tramp = mod->arch.tramp; - - if (module_trampoline_target(mod, tramp, &ptr)) { - pr_err("Failed to get trampoline target\n"); - return -EFAULT; - } - - pr_devel("trampoline target %lx", ptr); - - entry = ppc_global_function_entry((void *)addr); - /* This should match what was called */ - if (ptr != entry) { - pr_err("addr %lx does not match expected %lx\n", ptr, entry); - return -EINVAL; - } - - if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } - - return 0; -} -#else -static int __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) -{ - return 0; -} -#endif /* CONFIG_MODULES */ - -static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr) -{ - ppc_inst_t op; - void *ip = (void *)rec->ip; - unsigned long tramp, entry, ptr; - - /* Make sure we're being asked to patch branch to a known ftrace addr */ - entry = ppc_global_function_entry((void *)ftrace_caller); - ptr = ppc_global_function_entry((void *)addr); - - if (ptr != entry && IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) - entry = ppc_global_function_entry((void *)ftrace_regs_caller); - - if (ptr != entry) { - pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr); - return -EINVAL; - } - - /* Make sure we have a nop */ - if (copy_inst_from_kernel_nofault(&op, ip)) { - pr_err("Unable to read ftrace location %p\n", ip); - return -EFAULT; - } - - if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) { - pr_err("Unexpected call sequence at %p: %08lx\n", - ip, ppc_inst_as_ulong(op)); - return -EINVAL; - } - - tramp = find_ftrace_tramp((unsigned long)ip); - if (!tramp) { - pr_err("No ftrace trampolines reachable from %ps\n", ip); - return -EINVAL; - } - - if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { - pr_err("Error patching branch to ftrace tramp!\n"); - return -EINVAL; - } - - return 0; -} - -int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned long ip = rec->ip; - ppc_inst_t old, new; - - /* - * If the calling address is more that 24 bits away, - * then we had to use a trampoline to make the call. - * Otherwise just update the call site. - */ - if (test_24bit_addr(ip, addr)) { - /* within range */ - old = ppc_inst(PPC_RAW_NOP()); - new = ftrace_call_replace(ip, addr, 1); - return ftrace_modify_code(ip, old, new); - } else if (core_kernel_text(ip)) { - return __ftrace_make_call_kernel(rec, addr); - } else if (!IS_ENABLED(CONFIG_MODULES)) { - /* We should not get here without modules */ - return -EINVAL; - } - - /* - * Out of range jumps are called from modules. - * Being that we are converting from nop, it had better - * already have a module defined. - */ - if (!rec->arch.mod) { - pr_err("No module loaded\n"); - return -EINVAL; - } - - return __ftrace_make_call(rec, addr); -} - #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS #ifdef CONFIG_MODULES static int @@ -419,6 +263,37 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, } #endif +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned long tramp, ip = rec->ip; + ppc_inst_t old, new; + struct module *mod; + + old = ppc_inst(PPC_RAW_NOP()); + if (is_offset_in_branch_range(addr - ip)) { + /* Within range */ + new = ftrace_create_branch_inst(ip, addr, 1); + return ftrace_modify_code(ip, old, new); + } else if (core_kernel_text(ip)) { + /* We would be branching to one of our ftrace tramps */ + tramp = find_ftrace_tramp(ip); + if (!tramp) { + pr_err("0x%lx: No ftrace trampolines reachable\n", ip); + return -EINVAL; + } + new = ftrace_create_branch_inst(ip, tramp, 1); + return ftrace_modify_code(ip, old, new); + } else if (IS_ENABLED(CONFIG_MODULES)) { + /* Module code would be going to one of the module stubs */ + mod = rec->arch.mod; + tramp = (addr == (unsigned long)ftrace_caller ? mod->arch.tramp : mod->arch.tramp_regs); + new = ftrace_create_branch_inst(ip, tramp, 1); + return ftrace_modify_code(ip, old, new); + } + + return -EINVAL; +} + int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { unsigned long tramp, ip = rec->ip; From patchwork Wed Jun 7 16:55:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791839 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=DizYrUWe; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4QbttL1D9qz20Q8 for ; 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Thu, 8 Jun 2023 03:00:06 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 67DC060A49; Wed, 7 Jun 2023 17:00:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52A95C433EF; Wed, 7 Jun 2023 17:00:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157203; bh=YYUmVT6X8MT+8GtFX36c9ZC7SWw4gDef52giezsI0YE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DizYrUWe256dLTK1zBtQM2O6KUyS60ulg9aKRQqrzEbArD1Kc9+8P6UrolFH2mO6X HJEfXVcfbxYxSaZJx04mqxFSJHxUbqlJGiue9fWEiNohzEJAKvOZrRjHWFPTVVYvZ6 hxd9Om5QUmtFVHUU7eSIxpWXCYWxSP045tcV5q1GsLZiEQSMH9eps0XHgnj+7x4zqR ZOAb0G/u1fqO2+4oZuzifyzcqUgAWIY9heRXzaOAtuDnhGf4iNTxyNKwNwuX//xKQ+ Ixe2HybEyRKOzazYwPJWIY1vCxZLN/eqHfo0YpFLXw8fP0WIq+ZbP9aQRtsUj+uc+p uJfonoeTgbhRg== From: Naveen N Rao To: Subject: [RFC PATCH 12/15] powerpc/ftrace: Simplify ftrace_modify_call() Date: Wed, 7 Jun 2023 22:25:27 +0530 Message-Id: <606d6bac9179b35629a5eaecdd15a368f0100c10.1686151854.git.naveen@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Now that we validate the ftrace location during initialization in ftrace_init_nop(), we can simplify ftrace_modify_call() to patch-in the updated branch instruction without worrying about the instructions surrounding the ftrace location. Note that we continue to ensure we have the expected branch instruction at the ftrace location before patching it with the updated branch destination. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 161 ++++------------------------- 1 file changed, 21 insertions(+), 140 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 8d5d91b8ae85a0..c810343d1a6cd6 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -89,33 +89,11 @@ static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_ return ret; } -/* - * Helper functions that are the same for both PPC64 and PPC32. - */ -static int test_24bit_addr(unsigned long ip, unsigned long addr) -{ - addr = ppc_function_entry((void *)addr); - - return is_offset_in_branch_range(addr - ip); -} - static int is_bl_op(ppc_inst_t op) { return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0); } -static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) -{ - int offset; - - offset = PPC_LI(ppc_inst_val(op)); - /* make it signed */ - if (offset & 0x02000000) - offset |= 0xfe000000; - - return ip + (long)offset; -} - static unsigned long find_ftrace_tramp(unsigned long ip) { int i; @@ -130,115 +108,16 @@ static unsigned long find_ftrace_tramp(unsigned long ip) } #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS -#ifdef CONFIG_MODULES -static int -__ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, - unsigned long addr) +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) { - ppc_inst_t op; - unsigned long ip = rec->ip; - unsigned long entry, ptr, tramp; - struct module *mod = rec->arch.mod; - - /* If we never set up ftrace trampolines, then bail */ - if (!mod->arch.tramp || !mod->arch.tramp_regs) { - pr_err("No ftrace trampoline\n"); - return -EINVAL; - } - - /* read where this goes */ - if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { - pr_err("Fetching opcode failed.\n"); - return -EFAULT; - } - - /* Make sure that this is still a 24bit jump */ - if (!is_bl_op(op)) { - pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); - return -EINVAL; - } - - /* lets find where the pointer goes */ - tramp = find_bl_target(ip, op); - entry = ppc_global_function_entry((void *)old_addr); - - pr_devel("ip:%lx jumps to %lx", ip, tramp); - - if (tramp != entry) { - /* old_addr is not within range, so we must have used a trampoline */ - if (module_trampoline_target(mod, tramp, &ptr)) { - pr_err("Failed to get trampoline target\n"); - return -EFAULT; - } - - pr_devel("trampoline target %lx", ptr); - - /* This should match what was called */ - if (ptr != entry) { - pr_err("addr %lx does not match expected %lx\n", ptr, entry); - return -EINVAL; - } - } - - /* The new target may be within range */ - if (test_24bit_addr(ip, addr)) { - /* within range */ - if (patch_branch((u32 *)ip, addr, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } - - return 0; - } - - if (rec->flags & FTRACE_FL_REGS) - tramp = mod->arch.tramp_regs; - else - tramp = mod->arch.tramp; - - if (module_trampoline_target(mod, tramp, &ptr)) { - pr_err("Failed to get trampoline target\n"); - return -EFAULT; - } - - pr_devel("trampoline target %lx", ptr); - - entry = ppc_global_function_entry((void *)addr); - /* This should match what was called */ - if (ptr != entry) { - pr_err("addr %lx does not match expected %lx\n", ptr, entry); - return -EINVAL; - } - - if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } - - return 0; -} -#else -static int __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) -{ - return 0; -} -#endif - -int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, - unsigned long addr) -{ - unsigned long ip = rec->ip; + unsigned long tramp, tramp_old, ip = rec->ip; ppc_inst_t old, new; + struct module *mod; - /* - * If the calling address is more that 24 bits away, - * then we had to use a trampoline to make the call. - * Otherwise just update the call site. - */ - if (test_24bit_addr(ip, addr) && test_24bit_addr(ip, old_addr)) { - /* within range */ - old = ftrace_call_replace(ip, old_addr, 1); - new = ftrace_call_replace(ip, addr, 1); + if (is_offset_in_branch_range(old_addr - ip) && is_offset_in_branch_range(addr - ip)) { + /* Within range */ + old = ftrace_create_branch_inst(ip, old_addr, 1); + new = ftrace_create_branch_inst(ip, addr, 1); return ftrace_modify_code(ip, old, new); } else if (core_kernel_text(ip)) { /* @@ -246,20 +125,22 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, * variant, so there is nothing to do here */ return 0; - } else if (!IS_ENABLED(CONFIG_MODULES)) { - /* We should not get here without modules */ - return -EINVAL; + } else if (IS_ENABLED(CONFIG_MODULES)) { + /* Module code would be going to one of the module stubs */ + mod = rec->arch.mod; + if (addr == (unsigned long)ftrace_caller) { + tramp_old = mod->arch.tramp_regs; + tramp = mod->arch.tramp; + } else { + tramp_old = mod->arch.tramp; + tramp = mod->arch.tramp_regs; + } + old = ftrace_create_branch_inst(ip, tramp_old, 1); + new = ftrace_create_branch_inst(ip, tramp, 1); + return ftrace_modify_code(ip, old, new); } - /* - * Out of range jumps are called from modules. - */ - if (!rec->arch.mod) { - pr_err("No module loaded\n"); - return -EINVAL; - } - - return __ftrace_modify_call(rec, old_addr, addr); + return -EINVAL; } #endif From patchwork Wed Jun 7 16:55:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791840 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=JVZ8W6/p; 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envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=JVZ8W6/p; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4QbtrB5HPlz3dwh for ; Thu, 8 Jun 2023 03:00:10 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E79036176E; Wed, 7 Jun 2023 17:00:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6D6BC433D2; Wed, 7 Jun 2023 17:00:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157208; bh=OAmvO1ppsDvhykqzcuIKnvU8LaSIgpQXeRRc2imFhdo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JVZ8W6/pnAR5UPGnnFpePnu8VB0h2NR60Q3cyZxMs00A1zn7r7iDHQZUM2k2MfPqz c+jY+1ADK1+PBAUu7TURhUZA80ye3ZgTGb+qC1GgStfkTwv4Z3GTTuIRwgNmDFPc7z zZj3oyMpXdWd48euV1Lc0eKSG9ZfRnAr4nPV0kk8RZYetIyRLb6NM+JQfJjiu5LTsz 7uP5Gq4x4gEok9Owjq6ErzgUOW3219BXd0UHWjVEu9De6aNpqia2s1iC8cwLo6uil3 dCUCyKoTwbP3GBR6/8IbGuvK0PD+hQOwTNecbS1BV/8nThjzjWZ6dti4xH7M2+g6BO O1i7ua5vmMvrA== From: Naveen N Rao To: Subject: [RFC PATCH 13/15] powerpc/ftrace: Replace use of ftrace_call_replace() with ftrace_create_branch_inst() Date: Wed, 7 Jun 2023 22:25:28 +0530 Message-Id: <8ac06ab617ef7ddfff0b2425e8c670a73b6cb49e.1686151854.git.naveen@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" ftrace_create_branch_inst() is clearer about its intent than ftrace_call_replace(). Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index c810343d1a6cd6..4375ef71609c0a 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -41,19 +41,6 @@ static ppc_inst_t ftrace_create_branch_inst(unsigned long ip, unsigned long addr return op; } -static ppc_inst_t -ftrace_call_replace(unsigned long ip, unsigned long addr, int link) -{ - ppc_inst_t op; - - addr = ppc_function_entry((void *)addr); - - /* if (link) set op to 'bl' else 'b' */ - create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0); - - return op; -} - static inline int ftrace_read_inst(unsigned long ip, ppc_inst_t *op) { if (copy_inst_from_kernel_nofault(op, (void *)ip)) { @@ -275,14 +262,14 @@ int ftrace_update_ftrace_func(ftrace_func_t func) int ret; old = ppc_inst_read((u32 *)&ftrace_call); - new = ftrace_call_replace(ip, (unsigned long)func, 1); + new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1); ret = ftrace_modify_code(ip, old, new); /* Also update the regs callback function */ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) { ip = (unsigned long)(&ftrace_regs_call); old = ppc_inst_read((u32 *)&ftrace_regs_call); - new = ftrace_call_replace(ip, (unsigned long)func, 1); + new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1); ret = ftrace_modify_code(ip, old, new); } From patchwork Wed Jun 7 16:55:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791841 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=FZt4FBYp; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4QbtwC6S0Mz20Q8 for ; Thu, 8 Jun 2023 03:03:39 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4QbtwC3RQ8z3fFZ for ; Thu, 8 Jun 2023 03:03:39 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=FZt4FBYp; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=FZt4FBYp; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4QbtrH1J4wz3dxy for ; Thu, 8 Jun 2023 03:00:15 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 82D1060A49; Wed, 7 Jun 2023 17:00:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6654DC433D2; Wed, 7 Jun 2023 17:00:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157212; bh=L9WHXW4SqmcULA6WGvGWD1XJMxey5TSZDATAV2sm0jA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FZt4FBYpa31fMuYFyRhdKvymwY6BIq2tdK/S7aC6SxDxc9mGxeo34o01GTaFUxdE7 IV39TxBk0MmJq7xVNN17I9d39G9swVXnbX+BShUb7mvfh4pakX/CMzliAoVeR3wQ3G d/hfiz//FSW3CpE31kgXTmd9jvaF0SWTX844LTBOtmAA9AmrRPzpYQccaLuT9aiSeT jJkipF9Wx133CgKidOU7DJdLfhY6zVbUffoZK37by4Z1Bw1QZcps2XJgt5nziDl9Yw 4QT3/OxjlrbTQWKxBLny/ejSarCMN2J9rKLSK4+BmavSwstQM1V/z4wXIw6CROuC+z BaWawJUHGYAUg== From: Naveen N Rao To: Subject: [RFC PATCH 14/15] powerpc/ftrace: Implement ftrace_replace_code() Date: Wed, 7 Jun 2023 22:25:29 +0530 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Implement ftrace_replace_code() to consolidate logic from the different ftrace patching routines: ftrace_make_nop(), ftrace_make_call() and ftrace_modify_call(). Note that ftrace_make_call() is still required primarily to handle patching modules during their load time. The other two routines should no longer be called. This lays the groundwork to enable better control in patching ftrace locations, including the ability to nop-out preceding profiling instructions when ftrace is disabled. Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/trace/ftrace.c | 173 ++++++++++++++++------------- 1 file changed, 96 insertions(+), 77 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 4375ef71609c0a..fd1ef350c62c42 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -94,104 +94,123 @@ static unsigned long find_ftrace_tramp(unsigned long ip) return 0; } +static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_inst_t *call_inst) +{ + unsigned long ip = rec->ip; + unsigned long stub; + + if (is_offset_in_branch_range(addr - ip)) { + /* Within range */ + stub = addr; +#ifdef CONFIG_MODULES + } else if (rec->arch.mod) { + /* Module code would be going to one of the module stubs */ + stub = (addr == (unsigned long)ftrace_caller ? rec->arch.mod->arch.tramp : + rec->arch.mod->arch.tramp_regs); +#endif + } else if (core_kernel_text(ip)) { + /* We would be branching to one of our ftrace stubs */ + stub = find_ftrace_tramp(ip); + if (!stub) { + pr_err("0x%lx: No ftrace stubs reachable\n", ip); + return -EINVAL; + } + } else { + return -EINVAL; + } + + *call_inst = ftrace_create_branch_inst(ip, stub, 1); + return 0; +} + #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) { - unsigned long tramp, tramp_old, ip = rec->ip; - ppc_inst_t old, new; - struct module *mod; - - if (is_offset_in_branch_range(old_addr - ip) && is_offset_in_branch_range(addr - ip)) { - /* Within range */ - old = ftrace_create_branch_inst(ip, old_addr, 1); - new = ftrace_create_branch_inst(ip, addr, 1); - return ftrace_modify_code(ip, old, new); - } else if (core_kernel_text(ip)) { - /* - * We always patch out of range locations to go to the regs - * variant, so there is nothing to do here - */ - return 0; - } else if (IS_ENABLED(CONFIG_MODULES)) { - /* Module code would be going to one of the module stubs */ - mod = rec->arch.mod; - if (addr == (unsigned long)ftrace_caller) { - tramp_old = mod->arch.tramp_regs; - tramp = mod->arch.tramp; - } else { - tramp_old = mod->arch.tramp; - tramp = mod->arch.tramp_regs; - } - old = ftrace_create_branch_inst(ip, tramp_old, 1); - new = ftrace_create_branch_inst(ip, tramp, 1); - return ftrace_modify_code(ip, old, new); - } - + /* This should never be called since we override ftrace_replace_code() */ + WARN_ON(1); return -EINVAL; } #endif int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { - unsigned long tramp, ip = rec->ip; ppc_inst_t old, new; - struct module *mod; + int ret; + + /* This can only ever be called during module load */ + if (WARN_ON(!IS_ENABLED(CONFIG_MODULES) || core_kernel_text(rec->ip))) + return -EINVAL; old = ppc_inst(PPC_RAW_NOP()); - if (is_offset_in_branch_range(addr - ip)) { - /* Within range */ - new = ftrace_create_branch_inst(ip, addr, 1); - return ftrace_modify_code(ip, old, new); - } else if (core_kernel_text(ip)) { - /* We would be branching to one of our ftrace tramps */ - tramp = find_ftrace_tramp(ip); - if (!tramp) { - pr_err("0x%lx: No ftrace trampolines reachable\n", ip); - return -EINVAL; - } - new = ftrace_create_branch_inst(ip, tramp, 1); - return ftrace_modify_code(ip, old, new); - } else if (IS_ENABLED(CONFIG_MODULES)) { - /* Module code would be going to one of the module stubs */ - mod = rec->arch.mod; - tramp = (addr == (unsigned long)ftrace_caller ? mod->arch.tramp : mod->arch.tramp_regs); - new = ftrace_create_branch_inst(ip, tramp, 1); - return ftrace_modify_code(ip, old, new); - } + ret = ftrace_get_call_inst(rec, addr, &new); + if (ret) + return ret; - return -EINVAL; + return ftrace_modify_code(rec->ip, old, new); } int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { - unsigned long tramp, ip = rec->ip; - ppc_inst_t old, new; + /* + * This should never be called since we override ftrace_replace_code(), + * as well as ftrace_init_nop() + */ + WARN_ON(1); + return -EINVAL; +} - /* Nop-out the ftrace location */ - new = ppc_inst(PPC_RAW_NOP()); - if (is_offset_in_branch_range(addr - ip)) { - /* Within range */ - old = ftrace_create_branch_inst(ip, addr, 1); - return ftrace_modify_code(ip, old, new); - } else if (core_kernel_text(ip)) { - /* We would be branching to one of our ftrace tramps */ - tramp = find_ftrace_tramp(ip); - if (!tramp) { - pr_err("0x%lx: No ftrace trampolines reachable\n", ip); - return -EINVAL; +void ftrace_replace_code(int enable) +{ + ppc_inst_t old, new, call_inst, new_call_inst; + ppc_inst_t nop_inst = ppc_inst(PPC_RAW_NOP()); + unsigned long ip, new_addr, addr; + struct ftrace_rec_iter *iter; + struct dyn_ftrace *rec; + int ret = 0, update; + + for_ftrace_rec_iter(iter) { + rec = ftrace_rec_iter_record(iter); + ip = rec->ip; + + if (rec->flags & FTRACE_FL_DISABLED && !(rec->flags & FTRACE_FL_ENABLED)) + continue; + + addr = ftrace_get_addr_curr(rec); + new_addr = ftrace_get_addr_new(rec); + update = ftrace_update_record(rec, enable); + + switch (update) { + case FTRACE_UPDATE_IGNORE: + default: + continue; + case FTRACE_UPDATE_MODIFY_CALL: + ret = ftrace_get_call_inst(rec, new_addr, &new_call_inst); + ret |= ftrace_get_call_inst(rec, addr, &call_inst); + old = call_inst; + new = new_call_inst; + break; + case FTRACE_UPDATE_MAKE_NOP: + ret = ftrace_get_call_inst(rec, addr, &call_inst); + old = call_inst; + new = nop_inst; + break; + case FTRACE_UPDATE_MAKE_CALL: + ret = ftrace_get_call_inst(rec, new_addr, &call_inst); + old = nop_inst; + new = call_inst; + break; } - old = ftrace_create_branch_inst(ip, tramp, 1); - return ftrace_modify_code(ip, old, new); - } else if (IS_ENABLED(CONFIG_MODULES)) { - /* Module code would be going to one of the module stubs */ - if (!mod) - mod = rec->arch.mod; - tramp = (addr == (unsigned long)ftrace_caller ? mod->arch.tramp : mod->arch.tramp_regs); - old = ftrace_create_branch_inst(ip, tramp, 1); - return ftrace_modify_code(ip, old, new); + + if (!ret) + ret = ftrace_modify_code(ip, old, new); + if (ret) + goto out; } - return -EINVAL; +out: + if (ret) + ftrace_bug(ret, rec); + return; } int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) From patchwork Wed Jun 7 16:55:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 1791842 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=fo+lWdgx; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4QbtxK0kSPz20Q8 for ; Thu, 8 Jun 2023 03:04:36 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4QbtxH4yK5z3f83 for ; Thu, 8 Jun 2023 03:04:35 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=fo+lWdgx; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=naveen@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=fo+lWdgx; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4QbtrM4fnKz3dxc for ; Thu, 8 Jun 2023 03:00:19 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E8C9B64017; Wed, 7 Jun 2023 17:00:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8D96C4339B; Wed, 7 Jun 2023 17:00:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686157217; bh=YwdyMOFiMM4b+Oq4263LspVmP2AelPho5rnnpwWdmh4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fo+lWdgxhxlSD3N1QkTZwi89/m6iR4G6k8jatenF6dlOxeuh1kqa1UZvRG/NdbVwM P1NyU+o4sf77fnuS9Dliz4FcXct12JObIk0TYt4onBqF5SGWnz8OccbWfZ9JxOY2bK bX+cEqqCj3Zmu9v7irEbKh/P9lFKJMK4wRsNRlN7L8/UcFuEltOIrNTVL7SY+4gged pDXOcCchM17ApEsc6N1XvIdVj/nRmUEC9Wo5CqICdwfVHOsP/tzyUSfnGF2TrfqBdY 5PR1VgcYZ3RndtEdWGt/uZcL3iecTgtZmQpSbJlTr6512RrDzH5fGhJCHU20N8VOcm tsRNOKu5AftkA== From: Naveen N Rao To: Subject: [RFC PATCH 15/15] powerpc/ftrace: Add support for -fpatchable-function-entry Date: Wed, 7 Jun 2023 22:25:30 +0530 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt , Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" GCC v13.1 updated support for -fpatchable-function-entry on ppc64le to emit nops after the local entry point, rather than before it. This allows us to use this in the kernel for ftrace purposes. A new script is added under arch/powerpc/tools/ to help detect if nops are emitted after the function local entry point, or before the global entry point. With -fpatchable-function-entry, we no longer have the profiling instructions generated at function entry, so we only need to validate the presence of two nops at the ftrace location in ftrace_init_nop(). We patch the preceding instruction with 'mflr r0' to match the -mprofile-kernel ABI for subsequent ftrace use. This changes the profiling instructions used on ppc32. The default -pg option emits an additional 'stw' instruction after 'mflr r0' and before the branch to _mcount 'bl _mcount'. This is very similar to the original -mprofile-kernel implementation on ppc64le, where an additional 'std' instruction was used to save LR to its save location in the caller's stackframe. Subsequently, this additional store was removed in later compiler versions for performance reasons. The same reasons apply for ppc32 so we only patch in a 'mflr r0'. Signed-off-by: Naveen N Rao --- arch/powerpc/Kconfig | 14 +++++++--- arch/powerpc/Makefile | 5 ++++ arch/powerpc/include/asm/ftrace.h | 6 +++-- arch/powerpc/include/asm/vermagic.h | 4 ++- arch/powerpc/kernel/module_64.c | 2 +- arch/powerpc/kernel/trace/ftrace.c | 14 ++++++++-- arch/powerpc/kernel/trace/ftrace_entry.S | 2 ++ .../gcc-check-fpatchable-function-entry.sh | 26 +++++++++++++++++++ 8 files changed, 64 insertions(+), 9 deletions(-) create mode 100755 arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index bff5820b7cda14..9352d8e68152e1 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -187,6 +187,7 @@ config PPC select DYNAMIC_FTRACE if FUNCTION_TRACER select EDAC_ATOMIC_SCRUB select EDAC_SUPPORT + select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if ARCH_USING_PATCHABLE_FUNCTION_ENTRY select GENERIC_ATOMIC64 if PPC32 select GENERIC_CLOCKEVENTS_BROADCAST if SMP select GENERIC_CMOS_UPDATE @@ -227,8 +228,8 @@ config PPC select HAVE_DEBUG_KMEMLEAK select HAVE_DEBUG_STACKOVERFLOW select HAVE_DYNAMIC_FTRACE - select HAVE_DYNAMIC_FTRACE_WITH_ARGS if MPROFILE_KERNEL || PPC32 - select HAVE_DYNAMIC_FTRACE_WITH_REGS if MPROFILE_KERNEL || PPC32 + select HAVE_DYNAMIC_FTRACE_WITH_ARGS if ARCH_USING_PATCHABLE_FUNCTION_ENTRY || MPROFILE_KERNEL || PPC32 + select HAVE_DYNAMIC_FTRACE_WITH_REGS if ARCH_USING_PATCHABLE_FUNCTION_ENTRY || MPROFILE_KERNEL || PPC32 select HAVE_EBPF_JIT select HAVE_EFFICIENT_UNALIGNED_ACCESS select HAVE_FAST_GUP @@ -256,7 +257,7 @@ config PPC select HAVE_MOD_ARCH_SPECIFIC select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S) select HAVE_OPTPROBES - select HAVE_OBJTOOL if PPC32 || MPROFILE_KERNEL + select HAVE_OBJTOOL if ARCH_USING_PATCHABLE_FUNCTION_ENTRY || MPROFILE_KERNEL || PPC32 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL select HAVE_PERF_EVENTS select HAVE_PERF_EVENTS_NMI if PPC64 @@ -550,6 +551,13 @@ config MPROFILE_KERNEL depends on PPC64 && CPU_LITTLE_ENDIAN && FUNCTION_TRACER def_bool $(success,$(srctree)/arch/powerpc/tools/gcc-check-mprofile-kernel.sh $(CC) -I$(srctree)/include -D__KERNEL__) +config ARCH_USING_PATCHABLE_FUNCTION_ENTRY + depends on FUNCTION_TRACER && (PPC32 || PPC64_ELF_ABI_V2) + depends on $(cc-option,-fpatchable-function-entry=2) + def_bool y if PPC32 + def_bool $(success,$(srctree)/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh $(CC) -mlittle-endian) if PPC64 && CPU_LITTLE_ENDIAN + def_bool $(success,$(srctree)/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh $(CC) -mbig-endian) if PPC64 && CPU_BIG_ENDIAN + config HOTPLUG_CPU bool "Support for enabling/disabling CPUs" depends on SMP && (PPC_PSERIES || \ diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index dca73f673d7046..de39478b1c9e9f 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -148,11 +148,16 @@ CFLAGS-$(CONFIG_PPC32) += $(call cc-option, $(MULTIPLEWORD)) CFLAGS-$(CONFIG_PPC32) += $(call cc-option,-mno-readonly-in-sdata) ifdef CONFIG_FUNCTION_TRACER +ifdef CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY +KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY +CC_FLAGS_FTRACE := -fpatchable-function-entry=2 +else CC_FLAGS_FTRACE := -pg ifdef CONFIG_MPROFILE_KERNEL CC_FLAGS_FTRACE += -mprofile-kernel endif endif +endif CFLAGS-$(CONFIG_TARGET_CPU_BOOL) += -mcpu=$(CONFIG_TARGET_CPU) AFLAGS-$(CONFIG_TARGET_CPU_BOOL) += -mcpu=$(CONFIG_TARGET_CPU) diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 89fbae3caa1fc2..0d61e8080cece5 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -11,7 +11,7 @@ #define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR /* Ignore unused weak functions which will have larger offsets */ -#ifdef CONFIG_MPROFILE_KERNEL +#if defined(CONFIG_MPROFILE_KERNEL) || defined(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY) #define FTRACE_MCOUNT_MAX_OFFSET 12 #elif defined(CONFIG_PPC32) #define FTRACE_MCOUNT_MAX_OFFSET 8 @@ -22,7 +22,9 @@ extern void _mcount(void); static inline unsigned long ftrace_call_adjust(unsigned long addr) { - /* relocation of mcount call site is the same as the address */ + if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) + addr += MCOUNT_INSN_SIZE; + return addr; } diff --git a/arch/powerpc/include/asm/vermagic.h b/arch/powerpc/include/asm/vermagic.h index b054a8576e5deb..6f250fe506bd1c 100644 --- a/arch/powerpc/include/asm/vermagic.h +++ b/arch/powerpc/include/asm/vermagic.h @@ -2,7 +2,9 @@ #ifndef _ASM_VERMAGIC_H #define _ASM_VERMAGIC_H -#ifdef CONFIG_MPROFILE_KERNEL +#ifdef CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY +#define MODULE_ARCH_VERMAGIC_FTRACE "patchable-function-entry " +#elif defined(CONFIG_MPROFILE_KERNEL) #define MODULE_ARCH_VERMAGIC_FTRACE "mprofile-kernel " #else #define MODULE_ARCH_VERMAGIC_FTRACE "" diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c index 92570289ce08f5..7112adc597a80b 100644 --- a/arch/powerpc/kernel/module_64.c +++ b/arch/powerpc/kernel/module_64.c @@ -465,7 +465,7 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr, return 0; } -#ifdef CONFIG_MPROFILE_KERNEL +#if defined(CONFIG_MPROFILE_KERNEL) || defined(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY) static u32 stub_insns[] = { #ifdef CONFIG_PPC_KERNEL_PCREL diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index fd1ef350c62c42..a03aa4fd7a08ba 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -220,7 +220,12 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) int ret = 0; /* Verify instructions surrounding the ftrace location */ - if (IS_ENABLED(CONFIG_PPC32)) { + if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) { + /* Expect nops */ + ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_NOP())); + if (!ret) + ret = ftrace_validate_inst(ip, ppc_inst(PPC_RAW_NOP())); + } else if (IS_ENABLED(CONFIG_PPC32)) { /* Expected sequence: 'mflr r0', 'stw r0,4(r1)', 'bl _mcount' */ ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0))); if (!ret) @@ -250,7 +255,12 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) /* Nop-out the ftrace location */ new = ppc_inst(PPC_RAW_NOP()); addr = MCOUNT_ADDR; - if (is_offset_in_branch_range(addr - ip)) { + if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) { + /* we instead patch-in the 'mflr r0' */ + old = ppc_inst(PPC_RAW_NOP()); + new = ppc_inst(PPC_RAW_MFLR(_R0)); + ret = ftrace_modify_code(ip - 4, old, new); + } else if (is_offset_in_branch_range(addr - ip)) { /* Within range */ old = ftrace_create_branch_inst(ip, addr, 1); ret = ftrace_modify_code(ip, old, new); diff --git a/arch/powerpc/kernel/trace/ftrace_entry.S b/arch/powerpc/kernel/trace/ftrace_entry.S index e8339706e735b1..bab3ab1368a33f 100644 --- a/arch/powerpc/kernel/trace/ftrace_entry.S +++ b/arch/powerpc/kernel/trace/ftrace_entry.S @@ -250,6 +250,7 @@ livepatch_handler: blr #endif /* CONFIG_LIVEPATCH */ +#ifndef CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY _GLOBAL(mcount) _GLOBAL(_mcount) EXPORT_SYMBOL(_mcount) @@ -257,6 +258,7 @@ EXPORT_SYMBOL(_mcount) mtctr r12 mtlr r0 bctr +#endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER _GLOBAL(return_to_handler) diff --git a/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh b/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh new file mode 100755 index 00000000000000..06706903503b6c --- /dev/null +++ b/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh @@ -0,0 +1,26 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +set -e +set -o pipefail + +# To debug, uncomment the following line +# set -x + +# Output from -fpatchable-function-entry can only vary on ppc64 elfv2, so this +# should not be invoked for other targets. Therefore we can pass in -m64 and +# -mabi explicitly, to take care of toolchains defaulting to other targets. + +# Test whether the compile option -fpatchable-function-entry exists and +# generates appropriate code +echo "int func() { return 0; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -fpatchable-function-entry=2 - -o - 2> /dev/null | \ + grep -q "__patchable_function_entries" + +# Test whether nops are generated after the local entry point +echo "int x; int func() { return x; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -fpatchable-function-entry=2 - -o - 2> /dev/null | \ + awk 'BEGIN { RS = ";" } /\.localentry.*nop.*\n[[:space:]]*nop/ { print $0 }' | \ + grep -q "func:" + +exit 0