[lkml]   [2009]   [Nov]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: BUG: GCC-4.4.x changes the function frame on some functions
    On Thu, Nov 19, 2009 at 4:45 PM, H. Peter Anvin <> wrote:
    > On 11/19/2009 07:37 AM, Thomas Gleixner wrote:
    >> modified function start on a handful of functions only seen with gcc
    >> 4.4.x on x86 32 bit:
    >>       push   %edi
    >>       lea    0x8(%esp),%edi
    >>       and    $0xfffffff0,%esp
    >>       pushl  -0x4(%edi)
    >>       push   %ebp
    >>       mov    %esp,%ebp
    >>       ...
    >>       call   mcount
    > The real questions is why we're aligning the stack in the kernel.  It is
    > probably not what we want -- we don't use SSE for anything but a handful
    > of special cases in the kernel, and we don't want the overhead.

    It's likely because you have long long vars on the stack which is
    faster when they are aligned. -mno-stackrealign may do what you
    want (or may not, I have not checked). I assume you already
    use -mpreferred-stack-boundary=2.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2009-11-19 16:53    [W:0.020 / U:0.708 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site