[PATCH -tip 3/4] x86/process/32: Use correct type for 'gs' variable in __show_regs() to avoid zero-extension

[Uros Bizjak]

Change the type of 'gs' variable in __show_regs() from
'unsigned short' to 'unsigned int'. This prevents unwanted
zero-extension when storing the 16-bit segment register
into a wider general purpose register.

The code improves from:

  50:	8c ee                	mov    %gs,%esi
  52:	0f b7 f6             	movzwl %si,%esi
  ...
  be:	89 74 24 14          	mov    %esi,0x14(%esp)

to:

  50:	8c ef                	mov    %gs,%edi
  ...
  bb:	89 7c 24 14          	mov    %edi,0x14(%esp)

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
---
 arch/x86/kernel/process_32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 3ef15c2f152f..168dabf9853f 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -61,7 +61,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
 	unsigned long d0, d1, d2, d3, d6, d7;
-	unsigned short gs;
+	unsigned int gs;
 
 	savesegment(gs, gs);
 
-- 
2.53.0