[PATCH 16/17] x86: entry_64.S: trivial optimization for ENOSYS

[Denys Vlasenko <dvlasenk@redhat.com>]

This code uses a slightly shorter insn.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Oleg Nesterov <oleg@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: X86 ML <x86@kernel.org>
CC: Alexei Starovoitov <ast@plumgrid.com>
CC: Will Drewry <wad@chromium.org>
CC: Kees Cook <keescook@chromium.org>
CC: linux-kernel@vger.kernel.org
---
 arch/x86/kernel/entry_64.S | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 7bc8c24..5d639a6 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -272,6 +272,7 @@ system_call_fastpath:
 	ja badsys
 	movq %r10,%rcx
 	call *sys_call_table(,%rax,8)  # XXX:	 rip relative
+from_badsys:
 	movq %rax,RAX(%rsp)
 /*
  * Syscall return path ending with SYSRET (fast path)
@@ -334,8 +335,8 @@ sysret_signal:
 	jmp int_check_syscall_exit_work
 
 badsys:
-	movq $-ENOSYS,RAX(%rsp)
-	jmp ret_from_sys_call
+	movq	$-ENOSYS,%rax
+	jmp	from_badsys
 
 #ifdef CONFIG_AUDITSYSCALL
 	/*
-- 
1.8.1.4