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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 E9977C04EB8 for ; Mon, 10 Dec 2018 21:31:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B493A2084E for ; Mon, 10 Dec 2018 21:31:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B493A2084E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=altlinux.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729929AbeLJVbw (ORCPT ); Mon, 10 Dec 2018 16:31:52 -0500 Received: from vmicros1.altlinux.org ([194.107.17.57]:42628 "EHLO vmicros1.altlinux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728088AbeLJVbw (ORCPT ); Mon, 10 Dec 2018 16:31:52 -0500 Received: from mua.local.altlinux.org (mua.local.altlinux.org [192.168.1.14]) by vmicros1.altlinux.org (Postfix) with ESMTP id 4040D72CC66; Tue, 11 Dec 2018 00:31:50 +0300 (MSK) Received: by mua.local.altlinux.org (Postfix, from userid 508) id 32FF37CF48F; Tue, 11 Dec 2018 00:31:50 +0300 (MSK) Date: Tue, 11 Dec 2018 00:31:50 +0300 From: "Dmitry V. Levin" To: Oleg Nesterov , Arnd Bergmann Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] asm-generic/ptrace.h: add a comment about frame_pointer Message-ID: <20181210213150.GA18226@altlinux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I have been misled by comments in asm-generic/ptrace.h into thinking that frame_pointer() is universally available across architectures, which resulted in a wrong design decision. Add a comment about frame_pointer in a hope that it will help others to avoid this mistake in the future. Cc: Oleg Nesterov Cc: Arnd Bergmann Cc: linux-arch@vger.kernel.org Signed-off-by: Dmitry V. Levin --- include/asm-generic/ptrace.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/asm-generic/ptrace.h b/include/asm-generic/ptrace.h index 82e674f6b337..3186c30bd50d 100644 --- a/include/asm-generic/ptrace.h +++ b/include/asm-generic/ptrace.h @@ -59,6 +59,10 @@ static inline void user_stack_pointer_set(struct pt_regs *regs, #define SET_FP(regs, val) (GET_FP(regs) = (val)) #endif +/* + * Unlike instruction_pointer and user_stack_pointer, + * frame_pointer is not universally available across architectures. + */ static inline unsigned long frame_pointer(struct pt_regs *regs) { return GET_FP(regs); -- ldv