From: Jim Bos <jim876@xs4all.nl>
Date: Sat, 13 Nov 2010 11:13:53 +0000 (+0100)
Subject: i8k: Tell gcc that *regs gets clobbered
X-Git-Tag: v2.6.35.14~235
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e58c04b185972bebd832a9716a037aa1c5fab745;p=thirdparty%2Fkernel%2Fstable.git

i8k: Tell gcc that *regs gets clobbered

[ upstream commit 6b4e81db2552bad04100e7d5ddeed7e848f53b48 ]

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: Andi Kleen <ak@linux.intel.com>
---

diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
index 4cd8b227c11f3..0add4a667e933 100644
--- 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