linux-kernel - [tip:core/objtool] x86/xen: Mark xen_cpuid() stack frame as non-standard

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Message-ID: <tip-983bb6d254c77aaec581473e11c2eb859294f1f2@git.kernel.org>
Date:	Mon, 29 Feb 2016 02:59:06 -0800
From:	tip-bot for Josh Poimboeuf <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	luto@...nel.org, hpa@...or.com, bernd@...rovitsch.priv.at,
	david.vrabel@...rix.com, chris.j.arges@...onical.com,
	boris.ostrovsky@...cle.com, torvalds@...ux-foundation.org,
	tglx@...utronix.de, linux-kernel@...r.kernel.org, acme@...nel.org,
	mmarek@...e.cz, akpm@...ux-foundation.org, palves@...hat.com,
	jpoimboe@...hat.com, mingo@...nel.org, peterz@...radead.org,
	namhyung@...il.com, konrad.wilk@...cle.com, bp@...en8.de,
	jslaby@...e.cz
Subject: [tip:core/objtool] x86/xen: Mark xen_cpuid() stack frame as
 non-standard

Commit-ID:  983bb6d254c77aaec581473e11c2eb859294f1f2
Gitweb:     http://git.kernel.org/tip/983bb6d254c77aaec581473e11c2eb859294f1f2
Author:     Josh Poimboeuf <jpoimboe@...hat.com>
AuthorDate: Sun, 28 Feb 2016 22:22:36 -0600
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Mon, 29 Feb 2016 08:35:10 +0100

x86/xen: Mark xen_cpuid() stack frame as non-standard

objtool reports the following false positive warning:

  arch/x86/xen/enlighten.o: warning: objtool: xen_cpuid()+0x41: can't find jump dest instruction at .text+0x108

The warning is due to xen_cpuid()'s use of XEN_EMULATE_PREFIX to insert
some fake instructions which objtool doesn't know how to decode.

Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Bernd Petrovitsch <bernd@...rovitsch.priv.at>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Chris J Arges <chris.j.arges@...onical.com>
Cc: David Vrabel <david.vrabel@...rix.com>
Cc: Jiri Slaby <jslaby@...e.cz>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Michal Marek <mmarek@...e.cz>
Cc: Namhyung Kim <namhyung@...il.com>
Cc: Pedro Alves <palves@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: live-patching@...r.kernel.org
Link: http://lkml.kernel.org/r/bb88399840406629e3417831dc371ecd2842e2a6.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/xen/enlighten.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index d09e4c9..5c45a69 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -32,6 +32,7 @@
 #include <linux/gfp.h>
 #include <linux/memblock.h>
 #include <linux/edd.h>
+#include <linux/frame.h>
 
 #ifdef CONFIG_KEXEC_CORE
 #include <linux/kexec.h>
@@ -351,8 +352,8 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
 	*cx &= maskecx;
 	*cx |= setecx;
 	*dx &= maskedx;
-
 }
+STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */
 
 static bool __init xen_check_mwait(void)
 {