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

[tip-bot for Josh Poimboeuf]

Commit-ID:  983bb6d254c77aaec581473e11c2eb859294f1f2
Gitweb:     http://git.kernel.org/tip/983bb6d254c77aaec581473e11c2eb859294f1f2
Author:     Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Sun, 28 Feb 2016 22:22:36 -0600
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Bernd Petrovitsch <bernd@xxxxxxxxxxxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Chris J Arges <chris.j.arges@xxxxxxxxxxxxx>
Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Michal Marek <mmarek@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Pedro Alves <palves@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: live-patching@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/bb88399840406629e3417831dc371ecd2842e2a6.1456719558.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 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)
 {