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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71B8DC4332F for ; Fri, 15 Oct 2021 02:59:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A76161212 for ; Fri, 15 Oct 2021 02:59:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235164AbhJODBR (ORCPT ); Thu, 14 Oct 2021 23:01:17 -0400 Received: from linux.microsoft.com ([13.77.154.182]:58238 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235174AbhJODBQ (ORCPT ); Thu, 14 Oct 2021 23:01:16 -0400 Received: from x64host.home (unknown [47.187.212.181]) by linux.microsoft.com (Postfix) with ESMTPSA id D64C920B9D20; Thu, 14 Oct 2021 19:59:09 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com D64C920B9D20 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1634266750; bh=Sre2VpLzl4RVm2McLfD5iL1Uc+pnLRObb9ujvhfag6U=; h=From:To:Subject:Date:In-Reply-To:References:From; b=Z+AxsZl6I0JgvMqLrKwgz+4rtObTdr9Dqfbk3LTAN9EL8/wdtbKyhPq6PRQE2MpvM eDS6EScXgN15chPkStv/j0mhp+d/X8lli59q8ZMUiWRA8+WiuWtbCEQjr6xTi8PxJR RuAyETDy9v7OeSr+NxBm6nwbv+I/LMbM43zwWvw8= 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, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com Subject: [PATCH v10 07/11] arm64: Call stack_backtrace() only from within walk_stackframe() Date: Thu, 14 Oct 2021 21:58:43 -0500 Message-Id: <20211015025847.17694-8-madvenka@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211015025847.17694-1-madvenka@linux.microsoft.com> References: <20211015025847.17694-1-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, arch_stack_walk() calls start_backtrace() and walk_stackframe() separately. There is no need to do that. Instead, call start_backtrace() from within walk_stackframe(). In other words, walk_stackframe() is the only unwind function a consumer needs to call. Currently, the only consumer is arch_stack_walk(). In the future, arch_stack_walk_reliable() will be another consumer. start_backtrace(), unwind_frame() and walk_stackframe() are only used within arm64/kernel/stacktrace.c. Make them static and remove them from arch/arm64/include/asm/stacktrace.h. Currently, there is a check for a NULL task in unwind_frame(). It is not needed since all current consumers pass a non-NULL task. Use struct stackframe only within the unwind functions. Signed-off-by: Madhavan T. Venkataraman --- arch/arm64/include/asm/stacktrace.h | 6 ---- arch/arm64/kernel/stacktrace.c | 51 ++++++++++++++++------------- 2 files changed, 29 insertions(+), 28 deletions(-) diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h index 8aebc00c1718..c239f357d779 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); @@ -148,7 +145,4 @@ static inline bool on_accessible_stack(const struct task_struct *tsk, return false; } -void start_backtrace(struct stackframe *frame, unsigned long fp, - unsigned long pc); - #endif /* __ASM_STACKTRACE_H */ diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 776c4debb5a7..7d32cee9ef4b 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -33,8 +33,8 @@ */ -void start_backtrace(struct stackframe *frame, unsigned long fp, - unsigned long pc) +static void start_backtrace(struct stackframe *frame, unsigned long fp, + unsigned long pc) { frame->fp = fp; frame->pc = pc; @@ -63,14 +63,12 @@ void start_backtrace(struct stackframe *frame, unsigned long fp, * records (e.g. a cycle), determined based on the location and fp value of A * and the location (but not the fp value) of B. */ -int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) +static int notrace unwind_frame(struct task_struct *tsk, + struct stackframe *frame) { unsigned long fp = frame->fp; struct stack_info info; - if (!tsk) - tsk = current; - /* Final frame; nothing to unwind */ if (fp == (unsigned long)task_pt_regs(tsk)->stackframe) return -ENOENT; @@ -136,15 +134,21 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) } NOKPROBE_SYMBOL(unwind_frame); -void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame, - bool (*fn)(void *, unsigned long), void *data) +static void notrace walk_stackframe(struct task_struct *tsk, + unsigned long fp, unsigned long pc, + bool (*fn)(void *, unsigned long), + void *data) { + struct stackframe frame; + + start_backtrace(&frame, fp, pc); + while (1) { int ret; - if (!fn(data, frame->pc)) + if (!fn(data, frame.pc)) break; - ret = unwind_frame(tsk, frame); + ret = unwind_frame(tsk, &frame); if (ret < 0) break; } @@ -190,19 +194,22 @@ noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, struct task_struct *task, struct pt_regs *regs) { - struct stackframe frame; + unsigned long fp, pc; + + if (regs) { + fp = regs->regs[29]; + pc = regs->pc; + } else if (task == current) { + /* Skip arch_stack_walk() in the stack trace. */ + fp = (unsigned long)__builtin_frame_address(1); + pc = (unsigned long)__builtin_return_address(0); + } else { + /* Caller guarantees that the task is not running. */ + fp = thread_saved_fp(task); + pc = thread_saved_pc(task); + } + walk_stackframe(task, fp, pc, consume_entry, cookie); - if (regs) - start_backtrace(&frame, regs->regs[29], regs->pc); - else if (task == current) - start_backtrace(&frame, - (unsigned long)__builtin_frame_address(1), - (unsigned long)__builtin_return_address(0)); - else - start_backtrace(&frame, thread_saved_fp(task), - thread_saved_pc(task)); - - walk_stackframe(task, &frame, consume_entry, cookie); } #endif -- 2.25.1