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    Subject[tip:x86/asm] x86/asm/entry/64: Use smaller instructions
    Commit-ID:  47eb582e702880c302036d17341c7ea1a7dc2a53
    Gitweb: http://git.kernel.org/tip/47eb582e702880c302036d17341c7ea1a7dc2a53
    Author: Denys Vlasenko <dvlasenk@redhat.com>
    AuthorDate: Wed, 25 Mar 2015 18:18:15 +0100
    Committer: Ingo Molnar <mingo@kernel.org>
    CommitDate: Fri, 27 Mar 2015 09:57:06 +0100

    x86/asm/entry/64: Use smaller instructions

    The $AUDIT_ARCH_X86_64 parameter to syscall_trace_enter_phase1/2
    is a 32-bit constant, loading it with 32-bit MOV produces 5-byte
    insn instead of 10-byte MOVABS one.

    Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: Alexei Starovoitov <ast@plumgrid.com>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Kees Cook <keescook@chromium.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Oleg Nesterov <oleg@redhat.com>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Will Drewry <wad@chromium.org>
    Link: http://lkml.kernel.org/r/1427303896-24023-3-git-send-email-dvlasenk@redhat.com
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    ---
    arch/x86/kernel/entry_64.S | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
    index 9988c4b..f85d2cc 100644
    --- a/arch/x86/kernel/entry_64.S
    +++ b/arch/x86/kernel/entry_64.S
    @@ -305,7 +305,7 @@ system_call_fastpath:
    /* Do syscall entry tracing */
    tracesys:
    movq %rsp, %rdi
    - movq $AUDIT_ARCH_X86_64, %rsi
    + movl $AUDIT_ARCH_X86_64, %esi
    call syscall_trace_enter_phase1
    test %rax, %rax
    jnz tracesys_phase2 /* if needed, run the slow path */
    @@ -316,7 +316,7 @@ tracesys:
    tracesys_phase2:
    SAVE_EXTRA_REGS
    movq %rsp, %rdi
    - movq $AUDIT_ARCH_X86_64, %rsi
    + movl $AUDIT_ARCH_X86_64, %esi
    movq %rax,%rdx
    call syscall_trace_enter_phase2


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