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    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@redhat.com>
    AuthorDate: Sun, 28 Feb 2016 22:22:36 -0600
    Committer: Ingo Molnar <mingo@kernel.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@redhat.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
    Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
    Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Chris J Arges <chris.j.arges@canonical.com>
    Cc: David Vrabel <david.vrabel@citrix.com>
    Cc: Jiri Slaby <jslaby@suse.cz>
    Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Michal Marek <mmarek@suse.cz>
    Cc: Namhyung Kim <namhyung@gmail.com>
    Cc: Pedro Alves <palves@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: live-patching@vger.kernel.org
    Link: http://lkml.kernel.org/r/bb88399840406629e3417831dc371ecd2842e2a6.1456719558.git.jpoimboe@redhat.com
    Signed-off-by: Ingo Molnar <mingo@kernel.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)
    {
    \
     
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