From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754635AbcJZKnm (ORCPT ); Wed, 26 Oct 2016 06:43:42 -0400 Received: from terminus.zytor.com ([198.137.202.10]:58826 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752609AbcJZKnk (ORCPT ); Wed, 26 Oct 2016 06:43:40 -0400 Date: Wed, 26 Oct 2016 03:43:06 -0700 From: tip-bot for Steven Rostedt Message-ID: Cc: hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@kernel.org, viro@ZenIV.linux.org.uk, npiggin@gmail.com, tglx@linutronix.de, rostedt@goodmis.org, bp@alien8.de, nix.or.die@gmail.com Reply-To: bp@alien8.de, rostedt@goodmis.org, npiggin@gmail.com, tglx@linutronix.de, nix.or.die@gmail.com, hpa@zytor.com, viro@ZenIV.linux.org.uk, mingo@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20161024150148.4f9d90e4@gandalf.local.home> References: <20161024150148.4f9d90e4@gandalf.local.home> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86: Fix export for mcount and __fentry__ Git-Commit-ID: 5de0a8c0c240338cb5b73363b0673c6aa804bb1c X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 5de0a8c0c240338cb5b73363b0673c6aa804bb1c Gitweb: http://git.kernel.org/tip/5de0a8c0c240338cb5b73363b0673c6aa804bb1c Author: Steven Rostedt AuthorDate: Mon, 24 Oct 2016 15:01:48 -0400 Committer: Thomas Gleixner CommitDate: Wed, 26 Oct 2016 12:38:17 +0200 x86: Fix export for mcount and __fentry__ Commit 784d5699eddc5 ("x86: move exports to actual definitions") removed the EXPORT_SYMBOL(__fentry__) and EXPORT_SYMBOL(mcount) from x8664_ksyms_64.c, and added EXPORT_SYMBOL(function_hook) in mcount_64.S instead. The problem is that function_hook isn't a function at all, but a macro that is defined as either mcount or __fentry__ depending on the support from gcc. Originally, I thought this was a macro issue, like what __stringify() is used for. But the problem is a bit deeper. The Makefile.build has some magic that does post processing of files to create the CRC bindings. It does some searches for EXPORT_SYMBOL() and because it finds a macro name and not the actual functions, this causes function_hook not to be converted into mcount or __fentry__ and they are missed. Instead of adding more magic to Makefile.build, just add EXPORT_SYMBOL() for mcount and __fentry__ where the ifdef is used. Since this is assembly and not C, it doesn't require being set after the function is defined. Signed-off-by: Steven Rostedt Tested-by: Borislav Petkov Cc: Gabriel C Cc: Nicholas Piggin Cc: Al Viro Link: http://lkml.kernel.org/r/20161024150148.4f9d90e4@gandalf.local.home Signed-off-by: Thomas Gleixner --- arch/x86/kernel/mcount_64.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S index efe73aa..7b0d3da 100644 --- a/arch/x86/kernel/mcount_64.S +++ b/arch/x86/kernel/mcount_64.S @@ -18,8 +18,10 @@ #ifdef CC_USING_FENTRY # define function_hook __fentry__ +EXPORT_SYMBOL(__fentry__) #else # define function_hook mcount +EXPORT_SYMBOL(mcount) #endif /* All cases save the original rbp (8 bytes) */ @@ -295,7 +297,6 @@ trace: jmp fgraph_trace END(function_hook) #endif /* CONFIG_DYNAMIC_FTRACE */ -EXPORT_SYMBOL(function_hook) #endif /* CONFIG_FUNCTION_TRACER */ #ifdef CONFIG_FUNCTION_GRAPH_TRACER