From patchwork Mon Nov 23 13:08:36 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Slaby X-Patchwork-Id: 57149 Delivered-To: patch@linaro.org Received: by 10.112.155.196 with SMTP id vy4csp1423617lbb; Mon, 23 Nov 2015 05:09:46 -0800 (PST) X-Received: by 10.66.153.139 with SMTP id vg11mr35895288pab.118.1448284186750; Mon, 23 Nov 2015 05:09:46 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id ll4si19253717pab.39.2015.11.23.05.09.46; Mon, 23 Nov 2015 05:09:46 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754245AbbKWNJo (ORCPT + 28 others); Mon, 23 Nov 2015 08:09:44 -0500 Received: from mx2.suse.de ([195.135.220.15]:59299 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753838AbbKWNJi (ORCPT ); Mon, 23 Nov 2015 08:09:38 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E6EDCAD17; Mon, 23 Nov 2015 13:08:30 +0000 (UTC) From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Will Deacon , Jiri Slaby Subject: [PATCH 3.12 14/72] Revert "ARM64: unwind: Fix PC calculation" Date: Mon, 23 Nov 2015 14:08:36 +0100 Message-Id: X-Mailer: git-send-email 2.6.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Will Deacon 3.12-stable review patch. If anyone has any objections, please let me know. -- 2.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ =============== commit 9702970c7bd3e2d6fecb642a190269131d4ac16c upstream. This reverts commit e306dfd06fcb44d21c80acb8e5a88d55f3d1cf63. With this patch applied, we were the only architecture making this sort of adjustment to the PC calculation in the unwinder. This causes problems for ftrace, where the PC values are matched against the contents of the stack frames in the callchain and fail to match any records after the address adjustment. Whilst there has been some effort to change ftrace to workaround this, those patches are not yet ready for mainline and, since we're the odd architecture in this regard, let's just step in line with other architectures (like arch/arm/) for now. Signed-off-by: Will Deacon Signed-off-by: Jiri Slaby --- arch/arm64/kernel/stacktrace.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 048334bb2651..d25459ff57fc 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -48,11 +48,7 @@ int unwind_frame(struct stackframe *frame) frame->sp = fp + 0x10; frame->fp = *(unsigned long *)(fp); - /* - * -4 here because we care about the PC at time of bl, - * not where the return will go. - */ - frame->pc = *(unsigned long *)(fp + 8) - 4; + frame->pc = *(unsigned long *)(fp + 8); return 0; }