From patchwork Mon Nov 29 11:53:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1561131 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: 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=) 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 RSA-PSS (4096 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4J2kKN1Dtlz9s3q for ; Mon, 29 Nov 2021 22:54:15 +1100 (AEDT) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4J2kKM5lr6z3cnX for ; Mon, 29 Nov 2021 22:54:15 +1100 (AEDT) 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=csgroup.eu (client-ip=93.17.235.10; helo=pegase2.c-s.fr; envelope-from=christophe.leroy@csgroup.eu; receiver=) Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4J2kJS4f8hz3cCG for ; Mon, 29 Nov 2021 22:53:28 +1100 (AEDT) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4J2kJF6QMGz9sSc; Mon, 29 Nov 2021 12:53:17 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id gF7Ll6T2J5Dd; Mon, 29 Nov 2021 12:53:17 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4J2kJC420zz9sSg; Mon, 29 Nov 2021 12:53:15 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 71D778B781; Mon, 29 Nov 2021 12:53:15 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id X8K55WBD11JD; Mon, 29 Nov 2021 12:53:15 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (unknown [172.25.230.108]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 412F78B770; Mon, 29 Nov 2021 12:53:15 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 1ATBr7t2895129 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Mon, 29 Nov 2021 12:53:07 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 1ATBr7Tp895128; Mon, 29 Nov 2021 12:53:07 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Subject: [PATCH v4 5/5] powerpc/inst: Optimise copy_inst_from_kernel_nofault() Date: Mon, 29 Nov 2021 12:53:05 +0100 Message-Id: <27cccfa77f3ff91a26dc9d298698588cf35d9815.1638186774.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.33.1 In-Reply-To: <97a171efd8c582e2bae82c31f2a9519823a20d3f.1638186773.git.christophe.leroy@csgroup.eu> References: <97a171efd8c582e2bae82c31f2a9519823a20d3f.1638186773.git.christophe.leroy@csgroup.eu> MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1638186784; l=4590; s=20211009; h=from:subject:message-id; bh=5cncWdyLGDXpNOjK0yNkxRyTVcdpacNyA/eJmA5PCx4=; b=0DS32NkYCEPDjkbt9gm25XJmUlEclINcaMFp5MinTw52rkp9OOdy/F+tdRKGG6KIeNKsRsS7qzuq HLzmo5xTDj4omTzIsWHePmLk1ZRXakRsPSvPfF3Jbq0LE/yolkmx X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= 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: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" copy_inst_from_kernel_nofault() uses copy_from_kernel_nofault() to copy one or two 32bits words. This means calling an out-of-line function which itself calls back copy_from_kernel_nofault_allowed() then performs a generic copy with loops. Rewrite copy_inst_from_kernel_nofault() to do everything at a single place and use __get_kernel_nofault() directly to perform single accesses without loops. Allthough the generic function uses pagefault_disable(), it is not required on powerpc because do_page_fault() bails earlier when a kernel mode fault happens on a kernel address. As the function has now become very small, inline it. With this change, on an 8xx the time spent in the loop in ftrace_replace_code() is reduced by 23% at function tracer activation and 27% at nop tracer activation. The overall time to activate function tracer (measured with shell command 'time') is 570ms before the patch and 470ms after the patch. Even vmlinux size is reduced (by 152 instruction). Before the patch: 00000018 : 18: 94 21 ff e0 stwu r1,-32(r1) 1c: 7c 08 02 a6 mflr r0 20: 38 a0 00 04 li r5,4 24: 93 e1 00 1c stw r31,28(r1) 28: 7c 7f 1b 78 mr r31,r3 2c: 38 61 00 08 addi r3,r1,8 30: 90 01 00 24 stw r0,36(r1) 34: 48 00 00 01 bl 34 34: R_PPC_REL24 copy_from_kernel_nofault 38: 2c 03 00 00 cmpwi r3,0 3c: 40 82 00 0c bne 48 40: 81 21 00 08 lwz r9,8(r1) 44: 91 3f 00 00 stw r9,0(r31) 48: 80 01 00 24 lwz r0,36(r1) 4c: 83 e1 00 1c lwz r31,28(r1) 50: 38 21 00 20 addi r1,r1,32 54: 7c 08 03 a6 mtlr r0 58: 4e 80 00 20 blr After the patch (before inlining): 00000018 : 18: 3d 20 b0 00 lis r9,-20480 1c: 7c 04 48 40 cmplw r4,r9 20: 7c 69 1b 78 mr r9,r3 24: 41 80 00 14 blt 38 28: 81 44 00 00 lwz r10,0(r4) 2c: 38 60 00 00 li r3,0 30: 91 49 00 00 stw r10,0(r9) 34: 4e 80 00 20 blr 38: 38 60 ff de li r3,-34 3c: 4e 80 00 20 blr 40: 38 60 ff f2 li r3,-14 44: 4e 80 00 20 blr Signed-off-by: Christophe Leroy --- v4: Inline and remove pagefault_disable() v3: New Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/inst.h | 21 ++++++++++++++++++++- arch/powerpc/mm/maccess.c | 17 ----------------- 2 files changed, 20 insertions(+), 18 deletions(-) diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h index 86074e83d2a5..0aa811ff44d5 100644 --- a/arch/powerpc/include/asm/inst.h +++ b/arch/powerpc/include/asm/inst.h @@ -4,6 +4,8 @@ #include #include +#include +#include #define ___get_user_instr(gu_op, dest, ptr) \ ({ \ @@ -148,6 +150,23 @@ static inline char *__ppc_inst_as_str(char str[PPC_INST_STR_LEN], ppc_inst_t x) __str; \ }) -int copy_inst_from_kernel_nofault(ppc_inst_t *inst, u32 *src); +static inline int copy_inst_from_kernel_nofault(ppc_inst_t *inst, u32 *src) +{ + unsigned int val, suffix; + + if (unlikely(!is_kernel_addr((unsigned long)src))) + return -ERANGE; + + __get_kernel_nofault(&val, src, u32, Efault); + if (IS_ENABLED(CONFIG_PPC64) && get_op(val) == OP_PREFIX) { + __get_kernel_nofault(&suffix, src + 1, u32, Efault); + *inst = ppc_inst_prefix(val, suffix); + } else { + *inst = ppc_inst(val); + } + return 0; +Efault: + return -EFAULT; +} #endif /* _ASM_POWERPC_INST_H */ diff --git a/arch/powerpc/mm/maccess.c b/arch/powerpc/mm/maccess.c index 5abae96b2b46..ea821d0ffe16 100644 --- a/arch/powerpc/mm/maccess.c +++ b/arch/powerpc/mm/maccess.c @@ -11,20 +11,3 @@ bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size) { return is_kernel_addr((unsigned long)unsafe_src); } - -int copy_inst_from_kernel_nofault(ppc_inst_t *inst, u32 *src) -{ - unsigned int val, suffix; - int err; - - err = copy_from_kernel_nofault(&val, src, sizeof(val)); - if (err) - return err; - if (IS_ENABLED(CONFIG_PPC64) && get_op(val) == OP_PREFIX) { - err = copy_from_kernel_nofault(&suffix, src + 1, sizeof(suffix)); - *inst = ppc_inst_prefix(val, suffix); - } else { - *inst = ppc_inst(val); - } - return err; -}