i8k: Tell gcc that *regs gets clobbered

commit 6b4e81db2552bad04100e7d5ddeed7e848f53b48 upstream.

More recent GCC caused the i8k driver to stop working, on Slackware
compiler was upgraded from gcc-4.4.4 to gcc-4.5.1 after which it didn't
work anymore, meaning the driver didn't load or gave total nonsensical
output.

As it turned out the asm(..) statement forgot to mention it modifies the
*regs variable.

Credits to Andi Kleen and Andreas Schwab for providing the fix.

Signed-off-by: Jim Bos <jim876@xs4all.nl>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
index fc8cf7ac7f2bd5a09a176755dbe90f33deca744d..828fd24cdbf576cecf55a12dc19019cc96580b1a 100644 (file)
--- a/drivers/char/i8k.c
+++ b/drivers/char/i8k.c
@@ -141,7 +141,7 @@ static int i8k_smm(struct smm_regs *regs)
                "lahf\n\t"
                "shrl $8,%%eax\n\t"
                "andl $1,%%eax\n"
-               :"=a"(rc)
+               :"=a"(rc), "+m" (*regs)
                :    "a"(regs)
                :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 #else
@@ -166,7 +166,8 @@ static int i8k_smm(struct smm_regs *regs)
            "movl %%edx,0(%%eax)\n\t"
            "lahf\n\t"
            "shrl $8,%%eax\n\t"
-           "andl $1,%%eax\n":"=a"(rc)
+           "andl $1,%%eax\n"
+           :"=a"(rc), "+m" (*regs)
            :    "a"(regs)
            :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 #endif