[PATCH for review] [58/145] x86_64: AUX_DEVICE_INFO is one byte long, use 'movb'

Andi Kleen
2006-08-10T20:24:19Z

r

From: Diego Calleja <diegocg@gmail.com>
Bugzilla #6552 says:

"In arch/i386/boot/setup.S, movw is used instead of movb for PS/2 mouse
information, although it is unsigned char. This does not harm, because
the jmp instruction overwritten by movw is used before executing movw,
and never be used again"

I've no idea if this is a real bug or how it gets fixed, so I'm submitting
it for review instead of letting it die of boredom in bugzilla. Aditionally
to i386, I've changed x86-64, which mirrors the same code.

Credits to Yoshinori K. Okuji, who found the problem and suggested a fix.

Signed-off-by: Diego Calleja <diegocg@gmail.com>
Signed-off-by: Andi Kleen <ak@suse.de>

---
arch/i386/boot/setup.S | 4 ++--
arch/x86_64/boot/setup.S | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

Index: linux/arch/i386/boot/setup.S
===================================================================
--- linux.orig/arch/i386/boot/setup.S
+++ linux/arch/i386/boot/setup.S
@@ -494,12 +494,12 @@ no_voyager:
movw %cs, %ax # aka SETUPSEG
subw $DELTA_INITSEG, %ax # aka INITSEG
movw %ax, %ds
- movw $0, (0x1ff) # default is no pointing device
+ movb $0, (0x1ff) # default is no pointing device
int $0x11 # int 0x11: equipment list
testb $0x04, %al # check if mouse installed
jz no_psmouse

- movw $0xAA, (0x1ff) # device present
+ movb $0xAA, (0x1ff) # device present
no_psmouse:

#if defined(CONFIG_X86_SPEEDSTEP_SMI) || defined(CONFIG_X86_SPEEDSTEP_SMI_MODULE)
Index: linux/arch/x86_64/boot/setup.S
===================================================================
--- linux.orig/arch/x86_64/boot/setup.S
+++ linux/arch/x86_64/boot/setup.S
@@ -526,12 +526,12 @@ is_disk1:
movw %cs, %ax # aka SETUPSEG
subw $DELTA_INITSEG, %ax # aka INITSEG
movw %ax, %ds
- movw $0, (0x1ff) # default is no pointing device
+ movb $0, (0x1ff) # default is no pointing device
int $0x11 # int 0x11: equipment list
testb $0x04, %al # check if mouse installed
jz no_psmouse

- movw $0xAA, (0x1ff) # device present
+ movb $0xAA, (0x1ff) # device present
no_psmouse:

#include "../../i386/boot/edd.S"