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x86/entry/64: Use pop instead of movq in syscall_return_via_sysret 

Saves 64 bytes.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/6609b7f74ab31c36604ad746e019ea8495aec76c.1509609304.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2017-11-02 00:59:03 -07:00 committed by Ingo Molnar
parent e53178328c
commit 4fbb39108f
1 changed files with 11 additions and 3 deletions
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14
arch/x86/entry/entry_64.S
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@ -315,10 +315,18 @@ return_from_SYSCALL_64:
*/
syscall_return_via_sysret:
/* rcx and r11 are already restored (see code above) */
RESTORE_EXTRA_REGS
RESTORE_C_REGS_EXCEPT_RCX_R11
movq RSP(%rsp), %rsp
UNWIND_HINT_EMPTY
POP_EXTRA_REGS
popq %rsi /* skip r11 */
popq %r10
popq %r9
popq %r8
popq %rax
popq %rsi /* skip rcx */
popq %rdx
popq %rsi
popq %rdi
movq RSP-ORIG_RAX(%rsp), %rsp
USERGS_SYSRET64
END(entry_SYSCALL_64)