From patchwork Wed Nov 17 14:07:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 12692903 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 68742C433EF for ; Wed, 17 Nov 2021 14:10:57 +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 337B660FF2 for ; Wed, 17 Nov 2021 14:10:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 337B660FF2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.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:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ijB7FmbA08NifPCopjnLiPH5zgAELE4lvwABSaS5zLI=; b=LHJNNYAwZNcFxI as9J076B5dBIEAuE1EYgSVFzVDx+vItoQ9DviGx4KGxPTbC+01VLj5R31aezyI3HGOYXUmJDlPwZc B575IfBiG8mgn4xcfUUt9WswIc39HqepxkjuzlVPeJ/HCEfW4TtqflNJqiuwjqpRwdqwNfHsbnc7N RpqVRpIlXN1OOJsqISCPrQEBPQrlWtuZ4ZK0kMx9Cic7CuNcUWr6ilz5eCdI5m7piZWDO1LuVWt1y I7j4zIYHo6/Btxu3VQH1YodcT62YonH5yulIJu0bmd405U/cm+UpeKwbXvTvcxRxQL5u5utkmhFm5 L6JG6rPMVcU7/Y6YTvvg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mnLcy-00521H-Vu; Wed, 17 Nov 2021 14:09:33 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mnLbf-0051R2-0c for linux-arm-kernel@lists.infradead.org; Wed, 17 Nov 2021 14:08:12 +0000 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> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211117_060811_171612_C574CF86 X-CRM114-Status: UNSURE ( 9.77 ) X-CRM114-Notice: Please train this message. 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: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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;