x86/entry/64: Shorten TEST instructions

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>

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index a9c248b..5063ed1 100644 (file)
--- 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: