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    SubjectRe: [PATCH 07/18] x86/asm/64: Merge the fast and slow SYSRET paths
    On Thu, Oct 26, 2017 at 01:26:39AM -0700, Andy Lutomirski wrote:
    > They did almost the same thing. Remove a bunch of pointless
    > instructions (mostly hidden in macros) and reduce cognitive load by
    > merging them.
    >
    > Signed-off-by: Andy Lutomirski <luto@kernel.org>
    > ---
    > arch/x86/entry/entry_64.S | 6 +++---
    > 1 file changed, 3 insertions(+), 3 deletions(-)
    >
    > diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
    > index 9dafafa3e0ec..c855ee91a3a5 100644
    > --- a/arch/x86/entry/entry_64.S
    > +++ b/arch/x86/entry/entry_64.S
    > @@ -220,10 +220,9 @@ entry_SYSCALL_64_fastpath:
    > TRACE_IRQS_ON /* user mode is traced as IRQs on */
    > movq RIP(%rsp), %rcx
    > movq EFLAGS(%rsp), %r11
    > - RESTORE_C_REGS_EXCEPT_RCX_R11
    > - movq RSP(%rsp), %rsp
    > + addq $6*8, %rsp /* skip extra regs -- they were preserved */
    > UNWIND_HINT_EMPTY
    > - USERGS_SYSRET64
    > + jmp .Lpop_c_regs_except_rcx_r11_and_sysret
    >
    > 1:
    > /*
    > @@ -315,6 +314,7 @@ syscall_return_via_sysret:
    > /* rcx and r11 are already restored (see code above) */
    > UNWIND_HINT_EMPTY
    > POP_EXTRA_REGS
    > +.Lpop_c_regs_except_rcx_r11_and_sysret:

    .Lpop_regs_sysret I guess.

    --
    Regards/Gruss,
    Boris.

    SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
    --

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