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    Subject[34-longterm 112/196] i8k: Tell gcc that *regs gets clobbered
    Date
    From: Jim Bos <jim876@xs4all.nl>

    -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    If you see a problem with using this for longterm, please comment.
    -------------------

    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>
    ---
    drivers/char/i8k.c | 5 +++--
    1 file changed, 3 insertions(+), 2 deletions(-)

    diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
    index fc8cf7a..828fd24 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
    --
    1.7.9.3


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