Messages in this thread | | | Date | Sat, 23 Jun 2012 09:49:22 -0700 | Subject | Re: PATCH] Use -mpreferred-stack-boundary=3 on x86-64 if supported | From | "H.J. Lu" <> |
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On Sat, Jun 23, 2012 at 9:17 AM, H. Peter Anvin <hpa@zytor.com> wrote: > To keep gcc from paddong the stack to maintain a nonexistent alignment. > > Andi Kleen <andi@firstfloor.org> wrote: > >>> This patch uses -mpreferred-stack-boundary=3 on x86-64 if it is >>supported. >>> I have been running 3.4 kernel compiled with this option for weeks. >> >>But why? >> >>All the SSE code in the kernel should adjust manually. And the other >>code doesn't need it. >> >>Besides the entry points do not guarantee alignment. >> >>For the kernel it would be probably more useful to have a attribute >>per function that forces alignment.
There was an attempt from you to do it in 2007:
http://lkml.indiana.edu/hypermail/linux/kernel/0708.2/2604.html http://gcc.gnu.org/ml/gcc-patches/2007-07/msg01697.html
But the gcc patch was never checked in.
-- H.J.
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