[tip:x86/asm] x86/entry/64: Shorten TEST instructions

[tip-bot for Borislav Petkov]

Commit-ID:  1e4c4f610f774df6088d7c065b2dd4d22adba698
Gitweb:     https://git.kernel.org/tip/1e4c4f610f774df6088d7c065b2dd4d22adba698
Author:     Borislav Petkov <bp@xxxxxxx>
AuthorDate: Thu, 2 Nov 2017 13:09:26 +0100
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 2 Nov 2017 13:45:37 +0100

x86/entry/64: Shorten TEST instructions

Convert TESTL to TESTB and save 3 bytes per callsite.

No functionality change.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20171102120926.4srwerqrr7g72e2k@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/entry/entry_64.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 40e9933..84263c7 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -620,7 +620,7 @@ 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:
@@ -653,7 +653,7 @@ 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: