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=unavailable 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 4F11CC282C8 for ; Mon, 28 Jan 2019 16:24:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 15A3E2084A for ; Mon, 28 Jan 2019 16:24:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548692689; bh=kaVyc7Qcmbnp+b5HeNTRWZk6dumTsdFyQ355WS8qJFg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UqY4QwWksoRP+BxFWoZc5mjWvrE/GdpxJuO1ipAfxz9tFWYe/7HEoPJoIxDVBDWlv ZgrBdRiLmogRQJUIpw9TRwLMnAHcjR0sqYuJid6D4G0UTz/UiWWB1Fxd+ZyDiSkwIJ utGzed3V/+MDvfzw+dIZaVLa6T2XCGd1/YL41Rc8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389778AbfA1QYm (ORCPT ); Mon, 28 Jan 2019 11:24:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:33238 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389734AbfA1QYi (ORCPT ); Mon, 28 Jan 2019 11:24:38 -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 3CA0B2177E; Mon, 28 Jan 2019 16:24:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548692678; bh=kaVyc7Qcmbnp+b5HeNTRWZk6dumTsdFyQ355WS8qJFg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K9eWjmLqFs4crFSc+sp2ETv9GksOrsExs0PVh2JazNlLq4buV+n5bDya8WhCx9j/O M/JdaTe5ajKMtJDsFzYSWSoq76OSKWSupYBGh66hTPRbkNK6g+xhT9LCuGzt5+U/Up K0DB8h9Zojfr9Z9JOm6kVsIkUwTSqs2gVF20fMCo= 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 4.4 24/80] arm64: ftrace: don't adjust the LR value Date: Mon, 28 Jan 2019 11:23:05 -0500 Message-Id: <20190128162401.58841-24-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190128162401.58841-1-sashal@kernel.org> References: <20190128162401.58841-1-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 0f03a8fe2314..d18d15810d19 100644 --- a/arch/arm64/kernel/entry-ftrace.S +++ b/arch/arm64/kernel/entry-ftrace.S @@ -78,7 +78,6 @@ .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