From 4fbb39108f972437c44e5ffa781b56635d496826 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 2 Nov 2017 00:59:03 -0700 Subject: [PATCH] x86/entry/64: Use pop instead of movq in syscall_return_via_sysret Saves 64 bytes. Signed-off-by: Andy Lutomirski Reviewed-by: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/6609b7f74ab31c36604ad746e019ea8495aec76c.1509609304.git.luto@kernel.org Signed-off-by: Ingo Molnar --- 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 15539644..4f9b446 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -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) -- 2.7.4