[PATCH 4.14 055/159] x86/entry/64: Shorten TEST instructions

Greg Kroah-Hartman
2017-12-22T09:37:11Z

From: Borislav Petkov <bp@suse.de>

commit 1e4c4f610f774df6088d7c065b2dd4d22adba698 upstream.

Convert TESTL to TESTB and save 3 bytes per callsite.

No functionality change.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
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/20171102120926.4srwerqrr7g72e2k@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/entry/entry_64.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -621,7 +621,7 @@ GLOBAL(retint_user)
GLOBAL(swapgs_restore_regs_and_return_to_usermode)
#ifdef CONFIG_DEBUG_ENTRY
/* Assert that pt_regs indicates user mode. */
- testl $3, CS(%rsp)
+ testb $3, CS(%rsp)
jnz 1f
ud2
1:
@@ -654,7 +654,7 @@ retint_kernel:
GLOBAL(restore_regs_and_return_to_kernel)
#ifdef CONFIG_DEBUG_ENTRY
/* Assert that pt_regs indicates kernel mode. */
- testl $3, CS(%rsp)
+ testb $3, CS(%rsp)
jz 1f
ud2
1: