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 X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79AD3C282C8 for ; Mon, 28 Jan 2019 15:48:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38E9220880 for ; Mon, 28 Jan 2019 15:48:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548690508; bh=IyuBYT+o5n1tQPKvkmp596grXsQxcG0h3diz7rENV9M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dgrqB/vhRXu+scLkE0f8uigtJ+D/25d7uk+26dgOM1Tf9QIgCh3LX4fb9BAflon2P KEPyqDwSDLiPr2WSQpoQgIkYsEuLGOD3dSKqlChCqaTJeNgPExx/VzDcglVnftXIko JLNqAkJkdvebeU9F5DvI87ag8ZeZa9mZm4p4qwNI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728511AbfA1Ps1 (ORCPT ); Mon, 28 Jan 2019 10:48:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:33716 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727951AbfA1PsU (ORCPT ); Mon, 28 Jan 2019 10:48:20 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 074CE20880; Mon, 28 Jan 2019 15:48:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548690499; bh=IyuBYT+o5n1tQPKvkmp596grXsQxcG0h3diz7rENV9M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e1nmfrL/rcYuGSa66hlyb3rAN3kxYJpBE06cQtC/h0SeecmkdcguvqG9qbDUd8sL0 P5CQAkTVDOcBk+pkqFDZXtdZ452DvDZ12cOO93DrOfo9HeMDhkHVENuxxBxplWJvTJ F+qyEzj1FARvu73JnL8u0RLtH/Os4htOfIa6bIls= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Mark Rutland , AKASHI Takahiro , Ard Biesheuvel , Catalin Marinas , Torsten Duwe , Will Deacon , Sasha Levin Subject: [PATCH AUTOSEL 4.20 106/304] arm64: ftrace: don't adjust the LR value Date: Mon, 28 Jan 2019 10:40:23 -0500 Message-Id: <20190128154341.47195-106-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190128154341.47195-1-sashal@kernel.org> References: <20190128154341.47195-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mark Rutland [ Upstream commit 6e803e2e6e367db9a0d6ecae1bd24bb5752011bd ] The core ftrace code requires that when it is handed the PC of an instrumented function, this PC is the address of the instrumented instruction. This is necessary so that the core ftrace code can identify the specific instrumentation site. Since the instrumented function will be a BL, the address of the instrumented function is LR - 4 at entry to the ftrace code. This fixup is applied in the mcount_get_pc and mcount_get_pc0 helpers, which acquire the PC of the instrumented function. The mcount_get_lr helper is used to acquire the LR of the instrumented function, whose value does not require this adjustment, and cannot be adjusted to anything meaningful. No adjustment of this value is made on other architectures, including arm. However, arm64 adjusts this value by 4. This patch brings arm64 in line with other architectures and removes the adjustment of the LR value. Signed-off-by: Mark Rutland Cc: AKASHI Takahiro Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: Torsten Duwe Cc: Will Deacon Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/entry-ftrace.S | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S index 1175f5827ae1..295951f3172e 100644 --- a/arch/arm64/kernel/entry-ftrace.S +++ b/arch/arm64/kernel/entry-ftrace.S @@ -79,7 +79,6 @@ .macro mcount_get_lr reg ldr \reg, [x29] ldr \reg, [\reg, #8] - mcount_adjust_addr \reg, \reg .endm .macro mcount_get_lr_addr reg -- 2.19.1