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 08D98C433EF for ; Wed, 17 Nov 2021 14:08:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD49F61B71 for ; Wed, 17 Nov 2021 14:08:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238226AbhKQOLM (ORCPT ); Wed, 17 Nov 2021 09:11:12 -0500 Received: from foss.arm.com ([217.140.110.172]:57322 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238240AbhKQOLI (ORCPT ); Wed, 17 Nov 2021 09:11:08 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ECBD3142F; Wed, 17 Nov 2021 06:08:09 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 675B53F70D; Wed, 17 Nov 2021 06:08:07 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: aou@eecs.berkeley.edu, borntraeger@de.ibm.com, bp@alien8.de, broonie@kernel.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, gor@linux.ibm.com, hca@linux.ibm.com, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com, mark.rutland@arm.com, mhiramat@kernel.org, mingo@redhat.com, mpe@ellerman.id.au, palmer@dabbelt.com, paul.walmsley@sifive.com, peterz@infradead.org, rostedt@goodmis.org, tglx@linutronix.de, will@kernel.org Subject: [PATCH 6/9] arm64: Make return_address() use arch_stack_walk() Date: Wed, 17 Nov 2021 14:07:34 +0000 Message-Id: <20211117140737.44420-7-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20211117140737.44420-1-mark.rutland@arm.com> References: <20211117140737.44420-1-mark.rutland@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Madhavan T. Venkataraman" To enable RELIABLE_STACKTRACE and LIVEPATCH on arm64, we need to substantially rework arm64's unwinding code. As part of this, we want to minimize the set of unwind interfaces we expose, and avoid open-coding of unwind logic outside of stacktrace.c. Currently return_address() walks the stack of the current task by calling start_backtrace() with return_address as the PC and the frame pointer of return_address() as the next frame, iterating unwind steps using walk_stackframe(). This is functionally equivalent to calling arch_stack_walk() for the current stack, which will start from its caller (i.e. return_address()) as the PC and it's caller's frame record as the next frame. Make return_address() use arch_stackwalk(). This simplifies return_address(), and in future will alow us to make walk_stackframe() private to stacktrace.c. There should be no functional change as a result of this patch. Signed-off-by: Madhavan T. Venkataraman Tested-by: Mark Rutland Reviewed-by: Mark Brown Reviewed-by: Mark Rutland [Mark: elaborate commit message] Signed-off-by: Mark Rutland --- arch/arm64/kernel/return_address.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) 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; -- 2.11.0