From patchwork Sun Mar 11 12:38:15 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 131346 Delivered-To: patch@linaro.org Received: by 10.46.66.2 with SMTP id p2csp3055680lja; Sun, 11 Mar 2018 05:39:28 -0700 (PDT) X-Google-Smtp-Source: AG47ELsEnX/aFEuynwtY/mKTYx/jaRDpGiirqPqz/OeQd8GgoWAVjFujQoAlRgx7vxbg29rsIvI0 X-Received: by 2002:a17:902:6b04:: with SMTP id o4-v6mr4821367plk.201.1520771968332; Sun, 11 Mar 2018 05:39:28 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1520771968; cv=none; d=google.com; s=arc-20160816; b=Liyc63FIbGiX/h2r0BBfIkKfRgtVL7ki673VMLCxzADZNiGwXb52PTzR9BA9mAi3L7 Kee4b4xaMg+hk2hghIcFjzzRaQS9ouh0/BUPTDeh3jTxlPZNnok3eAgI34iPwwGKQTrS T3ARu+CCoT0f2dJjs/qkqupMGd8+LD5qVZGSRO66Du34VO9nEWiL2tMmsSZW/6hNhybm wIotjQdtkH23r9o/yfay1pD99EbkvffhAZRuAzL6ZaYIsry2Mq++MCG7FB4mx8aXuqFt Bm84e6RUNBTcdUZHx9DDfKuikJ08x25O0CbYb7L/2c9lT7uITK5AoYO5QOZpY/J7YT91 Kw8Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:dkim-signature:arc-authentication-results; bh=bbTSC6rTARnom9ckByI6VfHxqghKSu+vbbJy6E3JvOU=; b=glyoxQgi9IKFMXJXbD0ii/Od4My4zBoI3y2/LXTOroLrDWVm77d2v+YL8iiSVlNhb+ MHP0q8Ac05YGwTb9fIcX1jaDxdxFNkpd1EZf/yI6i8Ik1+PzvGkhM2r1f/R1pGcUoyDw 9V01FoVw3dJdwoH9ePBBxSMKKRDws1SwhB7FlL7USmAcqJBWt4+J0UK78+P+N6QqZxd+ fjv28/nh38j7IVQM5hZax8DsWUcJCzxQlPsZ5Qkndd4b2TxaCC52J1ZRtps58we1GfnZ AaUkjoTDDVHvylECg/Bl92GYhFt7lAPh4U6AOpZgQjBi4tIPajzoiYFeq5JjynGgL1CT pivA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=P/fjsi0+; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id q10si4171017pfc.183.2018.03.11.05.39.28; Sun, 11 Mar 2018 05:39:28 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=P/fjsi0+; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932331AbeCKMjZ (ORCPT + 28 others); Sun, 11 Mar 2018 08:39:25 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:36161 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932126AbeCKMjV (ORCPT ); Sun, 11 Mar 2018 08:39:21 -0400 Received: by mail-wm0-f68.google.com with SMTP id 188so11242812wme.1 for ; Sun, 11 Mar 2018 05:39:20 -0700 (PDT) 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=bbTSC6rTARnom9ckByI6VfHxqghKSu+vbbJy6E3JvOU=; b=P/fjsi0+pbLreU2S7U7w9l6MFak2naltGvAx9BZhwUVRh4mWBVqbAzyBYFDXd+b7nz E0QmVuMdTLMYDRG9M7X4+VCW0dm+dRx+fT+epfX+dc+kjyNqp3Ch3JXjkRCR/RgkHllU Ue20Y2byk0fEaT5T96/bqVq1344i14dMZo+wA= 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=bbTSC6rTARnom9ckByI6VfHxqghKSu+vbbJy6E3JvOU=; b=dJCM84oy3Twfz0DAsR1qmnrhFuqzZh565NcXdgoPSRLe+E3uX6Y/FiLkmLXE0bK12W c4OgTDbJwNppEdRlwPFNyJaChWP9nbg9X6Zh1vTvVH4sWyJ4VbGy5yiZRZHQnEnomNh3 502dzlcxmFSnI54Paqln6gBJaB8IKBZmoMMrtUy3n0YG730fL898qnOx4cy2Ltl+4cLh min6m7RxTd9J+HCSangK0BFAOmPCuK1dYtdg04u8y1JjJwsk3CrIpOQH7fMsHKbJP+bk 9yYR+xuRDTZ1heqoexCbokijm6PwkBZWZjbWSqHpTR4sGJPzux2rEv4yn0ZJHEjprVga We+A== X-Gm-Message-State: AElRT7EV5aCFHFJN5c+3WJg/JksZJrEoL2LKtd0tWlrQcvzmEZHUMHt0 ICZD1WNfbIh43gmcxw7HSKfwiQ== X-Received: by 10.28.158.205 with SMTP id h196mr2838678wme.25.1520771959268; Sun, 11 Mar 2018 05:39:19 -0700 (PDT) Received: from localhost.localdomain ([105.148.128.186]) by smtp.gmail.com with ESMTPSA id h188sm2569103wmf.37.2018.03.11.05.39.14 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 11 Mar 2018 05:39:18 -0700 (PDT) From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: Ard Biesheuvel , Arnd Bergmann , Kees Cook , Will Deacon , Michael Ellerman , Thomas Garnier , Thomas Gleixner , "Serge E. Hallyn" , Bjorn Helgaas , Benjamin Herrenschmidt , Russell King , Paul Mackerras , Catalin Marinas , Petr Mladek , Ingo Molnar , James Morris , Andrew Morton , Nicolas Pitre , Josh Poimboeuf , Steven Rostedt , Sergey Senozhatsky , Linus Torvalds , Jessica Yu , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org Subject: [PATCH v8 6/6] kernel: tracepoints: add support for relative references Date: Sun, 11 Mar 2018 12:38:15 +0000 Message-Id: <20180311123815.17916-7-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180311123815.17916-1-ard.biesheuvel@linaro.org> References: <20180311123815.17916-1-ard.biesheuvel@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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: Ingo Molnar Acked-by: Steven Rostedt (VMware) Signed-off-by: Ard Biesheuvel --- include/linux/tracepoint.h | 19 ++++++-- kernel/tracepoint.c | 49 +++++++++++--------- 2 files changed, 41 insertions(+), 27 deletions(-) -- 2.15.1 diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index c94f466d57ef..cdb0a9461d71 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -225,6 +225,19 @@ 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 @@ -234,11 +247,9 @@ 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 671b13457387..4ce8cc4bf2c3 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -326,6 +326,27 @@ 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(offset_to_ptr(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) { @@ -390,15 +411,9 @@ 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) @@ -449,8 +464,9 @@ 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; } } @@ -502,19 +518,6 @@ 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