[38/85] i8k: Avoid lahf in 64-bit code

From: Greg KH
Date: Thu Jun 16 2011 - 03:18:43 EST

2.6.33-longterm review patch. If anyone has any objections, please let us know.


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
@@ -138,8 +138,8 @@ 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"(regs)

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