[PATCH 06/18] x86/asm/64: Use pop instead of movq in syscall_return_via_sysret

Andy Lutomirski
2017-10-26T08:30:56Z

Saves 64 bytes.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/entry/entry_64.S | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index d6404a613df4..9dafafa3e0ec 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -313,10 +313,18 @@ 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)

--
2.13.6