From patchwork Mon Dec 25 20:54:37 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 852853 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=sparclinux-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.b="Q1HREJft"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3z5BHc0WXBz9ryr for ; Tue, 26 Dec 2017 07:56:44 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753286AbdLYUzs (ORCPT ); Mon, 25 Dec 2017 15:55:48 -0500 Received: from mail-wr0-f194.google.com ([209.85.128.194]:35006 "EHLO mail-wr0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753273AbdLYUzl (ORCPT ); Mon, 25 Dec 2017 15:55:41 -0500 Received: by mail-wr0-f194.google.com with SMTP id l19so21047457wrc.2 for ; Mon, 25 Dec 2017 12:55:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=FeRUkMrB+h9OzAG6tsXZHgHhFJKOYm9CVFNsKuS7D+M=; b=Q1HREJftT2aZs/JqWZHOsaU2Z+TagXl6eJx5d8qWSHZLETi/xqSxljw9g7z/0zATGE duUGBNR37ud1cZgQ+9l7EbvqnYeqHzsK4SsA2kf1hhrWK+rl77iGjFYfxJozrsjDhnwN bXow+s9jmxFGkTsydCr38z9kopa8/WalpD6Z0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=FeRUkMrB+h9OzAG6tsXZHgHhFJKOYm9CVFNsKuS7D+M=; b=li6/V09WmG3bXQo02m64xHHj4LjaSDiQjzId3IY7kQX6+1e6fcYjKeoT91Ia6K6NeB gfBaK396Zh0hoh/mf4u/zyPFxGEQ2CQ+4arBNaOr+UATkGJA2V+MttR/9jqAvq1ErV6y xL6xna2VQJT7xlHTgM/JFVLeMLZtxtM7yX2W/VTLfId21yZGOuGSf7TFQIxrk178fxPg M7792y26t1XSGD2/r//O/12V+eJzcizSkit5GoMaZRBxIvrE79RiPO/xd+pSSD2VlAiT mZXi/NUV/kyW8wsLEI0dg4h837RlL53SWW5Zyruz+fWuokmaNO9MD6BIRyIoFf5R3Glm lEkQ== X-Gm-Message-State: AKGB3mLjz8Jv9hcyqGGiN6KxzG4qIAaAFUJIhSav2tf50FqLiLfCt0op ZiS1inl9CBHIeWIiPvRrrtoGJg== X-Google-Smtp-Source: ACJfBoteICRvaVw9H9mJJrSL01+aQZvdzUzxu8wJD6cpdtXwoYC93Xxnvuqng/n5TPl+pbzXvxrMJg== X-Received: by 10.223.145.230 with SMTP id 93mr21913104wri.190.1514235340172; Mon, 25 Dec 2017 12:55:40 -0800 (PST) Received: from localhost.localdomain ([160.171.216.245]) by smtp.gmail.com with ESMTPSA id y42sm39552441wrc.96.2017.12.25.12.55.34 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Dec 2017 12:55:39 -0800 (PST) From: Ard Biesheuvel To: linux-kernel@vger.kernel.org Cc: Ard Biesheuvel , "H. Peter Anvin" , Ralf Baechle , Arnd Bergmann , Heiko Carstens , Kees Cook , Will Deacon , Michael Ellerman , Thomas Garnier , Thomas Gleixner , "Serge E. Hallyn" , Bjorn Helgaas , Benjamin Herrenschmidt , Russell King , Paul Mackerras , Catalin Marinas , "David S. Miller" , Petr Mladek , Ingo Molnar , James Morris , Andrew Morton , Nicolas Pitre , Josh Poimboeuf , Steven Rostedt , Martin Schwidefsky , Sergey Senozhatsky , Linus Torvalds , Jessica Yu , linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org Subject: [PATCH v5 5/8] kernel: tracepoints: add support for relative references Date: Mon, 25 Dec 2017 20:54:37 +0000 Message-Id: <20171225205440.14575-6-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171225205440.14575-1-ard.biesheuvel@linaro.org> References: <20171225205440.14575-1-ard.biesheuvel@linaro.org> Sender: sparclinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: sparclinux@vger.kernel.org To avoid the need for relocating absolute references to tracepoint structures at boot time when running relocatable kernels (which may take a disproportionate amount of space), add the option to emit these tables as relative references instead. Cc: Steven Rostedt Cc: Ingo Molnar Signed-off-by: Ard Biesheuvel --- include/linux/tracepoint.h | 19 ++++++-- kernel/tracepoint.c | 50 +++++++++++--------- 2 files changed, 42 insertions(+), 27 deletions(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index a26ffbe09e71..d02bf1a695e8 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -228,6 +228,19 @@ extern void syscall_unregfunc(void); return static_key_false(&__tracepoint_##name.key); \ } +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS +#define __TRACEPOINT_ENTRY(name) \ + asm(" .section \"__tracepoints_ptrs\", \"a\" \n" \ + " .balign 4 \n" \ + " .long " VMLINUX_SYMBOL_STR(__tracepoint_##name) " - .\n" \ + " .previous \n") +#else +#define __TRACEPOINT_ENTRY(name) \ + static struct tracepoint * const __tracepoint_ptr_##name __used \ + __attribute__((section("__tracepoints_ptrs"))) = \ + &__tracepoint_##name +#endif + /* * We have no guarantee that gcc and the linker won't up-align the tracepoint * structures, so we create an array of pointers that will be used for iteration @@ -237,11 +250,9 @@ extern void syscall_unregfunc(void); static const char __tpstrtab_##name[] \ __attribute__((section("__tracepoints_strings"))) = #name; \ struct tracepoint __tracepoint_##name \ - __attribute__((section("__tracepoints"))) = \ + __attribute__((section("__tracepoints"), used)) = \ { __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\ - static struct tracepoint * const __tracepoint_ptr_##name __used \ - __attribute__((section("__tracepoints_ptrs"))) = \ - &__tracepoint_##name; + __TRACEPOINT_ENTRY(name); #define DEFINE_TRACE(name) \ DEFINE_TRACE_FN(name, NULL, NULL); diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 685c50ae6300..05649fef106c 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -327,6 +327,28 @@ int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data) } EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); +static void for_each_tracepoint_range(struct tracepoint * const *begin, + struct tracepoint * const *end, + void (*fct)(struct tracepoint *tp, void *priv), + void *priv) +{ + if (!begin) + return; + + if (IS_ENABLED(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)) { + const int *iter; + + for (iter = (const int *)begin; iter < (const int *)end; iter++) + fct((struct tracepoint *)((unsigned long)iter + *iter), + priv); + } else { + struct tracepoint * const *iter; + + for (iter = begin; iter < end; iter++) + fct(*iter, priv); + } +} + #ifdef CONFIG_MODULES bool trace_module_has_bad_taint(struct module *mod) { @@ -391,15 +413,9 @@ EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier); * Ensure the tracer unregistered the module's probes before the module * teardown is performed. Prevents leaks of probe and data pointers. */ -static void tp_module_going_check_quiescent(struct tracepoint * const *begin, - struct tracepoint * const *end) +static void tp_module_going_check_quiescent(struct tracepoint *tp, void *priv) { - struct tracepoint * const *iter; - - if (!begin) - return; - for (iter = begin; iter < end; iter++) - WARN_ON_ONCE((*iter)->funcs); + WARN_ON_ONCE(tp->funcs); } static int tracepoint_module_coming(struct module *mod) @@ -450,8 +466,9 @@ static void tracepoint_module_going(struct module *mod) * Called the going notifier before checking for * quiescence. */ - tp_module_going_check_quiescent(mod->tracepoints_ptrs, - mod->tracepoints_ptrs + mod->num_tracepoints); + for_each_tracepoint_range(mod->tracepoints_ptrs, + mod->tracepoints_ptrs + mod->num_tracepoints, + tp_module_going_check_quiescent, NULL); break; } } @@ -503,19 +520,6 @@ static __init int init_tracepoints(void) __initcall(init_tracepoints); #endif /* CONFIG_MODULES */ -static void for_each_tracepoint_range(struct tracepoint * const *begin, - struct tracepoint * const *end, - void (*fct)(struct tracepoint *tp, void *priv), - void *priv) -{ - struct tracepoint * const *iter; - - if (!begin) - return; - for (iter = begin; iter < end; iter++) - fct(*iter, priv); -} - /** * for_each_kernel_tracepoint - iteration on all kernel tracepoints * @fct: callback