Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [7/98] i8k: Tell gcc that *regs gets clobbered | Date | Tue, 26 Jul 2011 17:34:59 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Jim Bos <jim876@xs4all.nl>
[ 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>
Index: linux-2.6.35.y/drivers/char/i8k.c =================================================================== --- linux-2.6.35.y.orig/drivers/char/i8k.c +++ linux-2.6.35.y/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
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