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    Subject[PATCH 4/8] x86/asm/entry/64: optimize [v]fork/clone stubs
    Date
    Replace "call func; ret" with "jmp func".

    Run-tested.

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

    diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
    index 8e3ba38..6ad30a7 100644
    --- a/arch/x86/kernel/entry_64.S
    +++ b/arch/x86/kernel/entry_64.S
    @@ -407,8 +407,7 @@ ENTRY(stub_\func)
    CFI_STARTPROC
    DEFAULT_FRAME 0, 8 /* offset 8: return address */
    SAVE_EXTRA_REGS 8
    - call sys_\func
    - ret
    + jmp sys_\func
    CFI_ENDPROC
    END(stub_\func)
    .endm
    --
    1.8.1.4


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