From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2ABF4C4320A for ; Thu, 12 Aug 2021 19:06:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 060C560EB2 for ; Thu, 12 Aug 2021 19:06:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235669AbhHLTGl (ORCPT ); Thu, 12 Aug 2021 15:06:41 -0400 Received: from linux.microsoft.com ([13.77.154.182]:60534 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235640AbhHLTGk (ORCPT ); Thu, 12 Aug 2021 15:06:40 -0400 Received: from x64host.home (unknown [47.187.212.181]) by linux.microsoft.com (Postfix) with ESMTPSA id B9255209C3B8; Thu, 12 Aug 2021 12:06:13 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com B9255209C3B8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1628795174; bh=a8u879OZglm+Zxz5cwOfWelTPIwh5C5mhpNdFIotC2A=; h=From:To:Subject:Date:In-Reply-To:References:From; b=JjbHatampnC1XUN3QAhxCD48SDdfu3ZW7t1AcCO2P+8LLJ1ejEWxS+E3vGfjiVjg4 50PKyFmijjbEA5jRBv1Dj12QVof7bgAjPp1FFX5Ly/ihg8NuTV5Ero9G1Djd4hur/Q l3xMTTBZoRQXJm8tnVKCHsfD3n7c8AiKfqgFWJBQ= From: madvenka@linux.microsoft.com To: mark.rutland@arm.com, broonie@kernel.org, jpoimboe@redhat.com, ardb@kernel.org, nobuta.keiya@fujitsu.com, sjitindarsingh@gmail.com, catalin.marinas@arm.com, will@kernel.org, jmorris@namei.org, pasha.tatashin@soleen.com, jthierry@redhat.com, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com Subject: [RFC PATCH v8 1/4] arm64: Make all stack walking functions use arch_stack_walk() Date: Thu, 12 Aug 2021 14:06:00 -0500 Message-Id: <20210812190603.25326-2-madvenka@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210812190603.25326-1-madvenka@linux.microsoft.com> References: <20210812190603.25326-1-madvenka@linux.microsoft.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org From: "Madhavan T. Venkataraman" Currently, there are multiple functions in ARM64 code that walk the stack using start_backtrace() and unwind_frame(). Convert all of them to use arch_stack_walk(). This makes maintenance easier. Here is the list of functions: perf_callchain_kernel() get_wchan() return_address() dump_backtrace() profile_pc() Signed-off-by: Madhavan T. Venkataraman --- arch/arm64/include/asm/stacktrace.h | 3 --- arch/arm64/kernel/perf_callchain.c | 5 +--- arch/arm64/kernel/process.c | 39 ++++++++++++++++++----------- arch/arm64/kernel/return_address.c | 6 +---- arch/arm64/kernel/stacktrace.c | 38 +++------------------------- arch/arm64/kernel/time.c | 22 +++++++++------- 6 files changed, 43 insertions(+), 70 deletions(-) diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h index 8aebc00c1718..e43dea1c6b41 100644 --- a/arch/arm64/include/asm/stacktrace.h +++ b/arch/arm64/include/asm/stacktrace.h @@ -61,9 +61,6 @@ struct stackframe { #endif }; -extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame); -extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame, - bool (*fn)(void *, unsigned long), void *data); extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk, const char *loglvl); diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c index 4a72c2727309..2f289013c9c9 100644 --- a/arch/arm64/kernel/perf_callchain.c +++ b/arch/arm64/kernel/perf_callchain.c @@ -147,15 +147,12 @@ static bool callchain_trace(void *data, unsigned long pc) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - struct stackframe frame; - if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) { /* We don't support guest os callchain now */ return; } - start_backtrace(&frame, regs->regs[29], regs->pc); - walk_stackframe(current, &frame, callchain_trace, entry); + arch_stack_walk(callchain_trace, entry, current, regs); } unsigned long perf_instruction_pointer(struct pt_regs *regs) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index c8989b999250..52c12fd26407 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -544,11 +544,28 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, return last; } +struct wchan_info { + unsigned long pc; + int count; +}; + +static bool get_wchan_cb(void *arg, unsigned long pc) +{ + struct wchan_info *wchan_info = arg; + + if (!in_sched_functions(pc)) { + wchan_info->pc = pc; + return false; + } + wchan_info->count--; + return !!wchan_info->count; +} + unsigned long get_wchan(struct task_struct *p) { - struct stackframe frame; - unsigned long stack_page, ret = 0; - int count = 0; + unsigned long stack_page; + struct wchan_info wchan_info; + if (!p || p == current || task_is_running(p)) return 0; @@ -556,20 +573,12 @@ unsigned long get_wchan(struct task_struct *p) if (!stack_page) return 0; - start_backtrace(&frame, thread_saved_fp(p), thread_saved_pc(p)); + wchan_info.pc = 0; + wchan_info.count = 16; + arch_stack_walk(get_wchan_cb, &wchan_info, p, NULL); - do { - if (unwind_frame(p, &frame)) - goto out; - if (!in_sched_functions(frame.pc)) { - ret = frame.pc; - goto out; - } - } while (count++ < 16); - -out: put_task_stack(p); - return ret; + return wchan_info.pc; } unsigned long arch_align_stack(unsigned long sp) diff --git a/arch/arm64/kernel/return_address.c b/arch/arm64/kernel/return_address.c index a6d18755652f..92a0f4d434e4 100644 --- a/arch/arm64/kernel/return_address.c +++ b/arch/arm64/kernel/return_address.c @@ -35,15 +35,11 @@ NOKPROBE_SYMBOL(save_return_addr); void *return_address(unsigned int level) { struct return_address_data data; - struct stackframe frame; data.level = level + 2; data.addr = NULL; - start_backtrace(&frame, - (unsigned long)__builtin_frame_address(0), - (unsigned long)return_address); - walk_stackframe(current, &frame, save_return_addr, &data); + arch_stack_walk(save_return_addr, &data, current, NULL); if (!data.level) return data.addr; diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 8982a2b78acf..1800310f92be 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -151,23 +151,21 @@ void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame, } NOKPROBE_SYMBOL(walk_stackframe); -static void dump_backtrace_entry(unsigned long where, const char *loglvl) +static bool dump_backtrace_entry(void *arg, unsigned long where) { + char *loglvl = arg; printk("%s %pSb\n", loglvl, (void *)where); + return true; } void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk, const char *loglvl) { - struct stackframe frame; - int skip = 0; - pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); if (regs) { if (user_mode(regs)) return; - skip = 1; } if (!tsk) @@ -176,36 +174,8 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk, if (!try_get_task_stack(tsk)) return; - if (tsk == current) { - start_backtrace(&frame, - (unsigned long)__builtin_frame_address(0), - (unsigned long)dump_backtrace); - } else { - /* - * task blocked in __switch_to - */ - start_backtrace(&frame, - thread_saved_fp(tsk), - thread_saved_pc(tsk)); - } - printk("%sCall trace:\n", loglvl); - do { - /* skip until specified stack frame */ - if (!skip) { - dump_backtrace_entry(frame.pc, loglvl); - } else if (frame.fp == regs->regs[29]) { - skip = 0; - /* - * Mostly, this is the case where this function is - * called in panic/abort. As exception handler's - * stack frame does not contain the corresponding pc - * at which an exception has taken place, use regs->pc - * instead. - */ - dump_backtrace_entry(regs->pc, loglvl); - } - } while (!unwind_frame(tsk, &frame)); + arch_stack_walk(dump_backtrace_entry, (void *)loglvl, tsk, regs); put_task_stack(tsk); } diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c index eebbc8d7123e..671b3038a772 100644 --- a/arch/arm64/kernel/time.c +++ b/arch/arm64/kernel/time.c @@ -32,22 +32,26 @@ #include #include +static bool profile_pc_cb(void *arg, unsigned long pc) +{ + unsigned long *prof_pc = arg; + + if (in_lock_functions(pc)) + return true; + *prof_pc = pc; + return false; +} + unsigned long profile_pc(struct pt_regs *regs) { - struct stackframe frame; + unsigned long prof_pc = 0; if (!in_lock_functions(regs->pc)) return regs->pc; - start_backtrace(&frame, regs->regs[29], regs->pc); - - do { - int ret = unwind_frame(NULL, &frame); - if (ret < 0) - return 0; - } while (in_lock_functions(frame.pc)); + arch_stack_walk(profile_pc_cb, &prof_pc, current, regs); - return frame.pc; + return prof_pc; } EXPORT_SYMBOL(profile_pc); -- 2.25.1