From patchwork Fri Oct 15 02:34:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Madhavan T. Venkataraman" X-Patchwork-Id: 12559759 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 6419FC433F5 for ; Fri, 15 Oct 2021 02:39:13 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2F926610D1 for ; Fri, 15 Oct 2021 02:39:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2F926610D1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Cc:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=SR8otQcmol0Z+vRuUxFfq/5QRcVLph5I2TY6vFNc6+M=; b=KsKLurmeW9O6u5 GkI7UGPqO6TzrD//kZ/gJydxX4UFPLDnE7yKrvJukLHvj+3XYgDnN7vtnXCU8CZrYxRZHy3rnaCUT SiVr+0AAa6r0PyFYU9SP2cPKAg+gh+f+VRjXFOF9p0iUTp1U0q2lYZuWSsjieDDbQSCqeSemDFoX+ g0vZ1ca9DtiDbSblLOb7I7oyCx0wii5aY3GuQCzma2fbGrSvkoZEd+e4X7T7rRgGypDJcq7uGKze8 6LrGwT5eTrdRKzmpflGxVWJg4jzuOOflgg6/POEFlR5OPM3CAY3k3kJiuDBorxobXdI3n5V29BwzE R1CLCQIp9MG1lECIeiww==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mbD6Y-0055lU-23; Fri, 15 Oct 2021 02:37:54 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mbD3l-0054Mz-M2 for linux-arm-kernel@lists.infradead.org; Fri, 15 Oct 2021 02:35:03 +0000 Received: from x64host.home (unknown [47.187.212.181]) by linux.microsoft.com (Postfix) with ESMTPSA id A775820B9D22; Thu, 14 Oct 2021 19:35:00 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com A775820B9D22 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1634265301; bh=Sre2VpLzl4RVm2McLfD5iL1Uc+pnLRObb9ujvhfag6U=; h=From:To:Subject:Date:In-Reply-To:References:From; b=b2wt6Eo4tXd7REs0soSvOigcsjVBosSp8D6g2YrtOUCyaz3NHtLoY2jW4vBkSMQFI NSDiqRd72Njsrzac2c3TyfX+OXGOIE8gYOatvph5/eddnpzNvLFmno6gFNB9YPUu9E hSNuDY/7iEOUOmnj+ngsHAalvweFody3YkGoN7OE= 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 v9 07/11] arm64: Call stack_backtrace() only from within walk_stackframe() Date: Thu, 14 Oct 2021 21:34:11 -0500 Message-Id: <20211015023413.16614-10-madvenka@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211015023413.16614-1-madvenka@linux.microsoft.com> References: <20211015023413.16614-1-madvenka@linux.microsoft.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211014_193501_826504_67D3318E X-CRM114-Status: GOOD ( 14.70 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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