[136/165] i8k: Avoid lahf in 64-bit code

From: Greg KH
Date: Wed Jun 01 2011 - 04:27:24 EST


2.6.39-stable review patch. If anyone has any objections, please let us know.

------------------
Content-Length: 1060
Lines: 35

From: Luca Tettamanti <kronos.it@xxxxxxxxx>

commit bc1f419c76a2d6450413ce4349f4e4a07be011d5 upstream.

i8k uses lahf to read the flag register in 64-bit code; early x86-64
CPUs, however, lack this instruction and we get an invalid opcode
exception at runtime.
Use pushf to load the flag register into the stack instead.

Signed-off-by: Luca Tettamanti <kronos.it@xxxxxxxxx>
Reported-by: Jeff Rickman <jrickman@xxxxxxxxxxx>
Tested-by: Jeff Rickman <jrickman@xxxxxxxxxxx>
Tested-by: Harry G McGavran Jr <w5pny@xxxxxxxx>
Cc: Massimo Dal Zotto <dz@xxxxxxxxxx>
Signed-off-by: Jean Delvare <khali@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
drivers/char/i8k.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/char/i8k.c
+++ b/drivers/char/i8k.c
@@ -139,8 +139,8 @@ static int i8k_smm(struct smm_regs *regs
"movl %%edi,20(%%rax)\n\t"
"popq %%rdx\n\t"
"movl %%edx,0(%%rax)\n\t"
- "lahf\n\t"
- "shrl $8,%%eax\n\t"
+ "pushfq\n\t"
+ "popq %%rax\n\t"
"andl $1,%%eax\n"
:"=a"(rc)
: "a"(regs)


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/