i8k: Avoid lahf in 64-bit code
Luca Tettamanti [Wed, 25 May 2011 18:43:31 +0000 (20:43 +0200)]
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@gmail.com>
Reported-by: Jeff Rickman <jrickman@myamigos.us>
Tested-by: Jeff Rickman <jrickman@myamigos.us>
Tested-by: Harry G McGavran Jr <w5pny@arrl.net>
Cc: stable@kernel.org
Cc: Massimo Dal Zotto <dz@debian.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/char/i8k.c

index d72433f..ee01716 100644 (file)
@@ -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)