lkml.org 
[lkml]   [2011]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] x86-64: Prevent gcc from optimizing away venosys_1()
On Fri, Jun 03, 2011 at 05:32:06PM -0400, Dave Anderson wrote:
>
>
> ----- Original Message -----
> > > return 0;
> > > }
> > >
> > > -static long __vsyscall(3) venosys_1(void)
> > > +long __vsyscall(3) venosys_1(void)
> >
> > Better add a __used too. Otherwise it can be optimized out again
> > in some builds e.g. when someone enables gc-sections for the linker.
>
> Considering that all of the vsyscall prototypes have this attribute:
>
> #define __vsyscall(nr) \
> __attribute__ ((unused, __section__(".vsyscall_" #nr))) notrace
>
> How would any of them work?

unused is just to prevent warnings I think. used stops the optimizer
from throwing it away.

It would make more sense to drop the unused and add an used. I think
used prevents the warnings too.

-Andi

--
ak@linux.intel.com -- Speaking for myself only.


\
 
 \ /
  Last update: 2011-06-03 23:39    [W:0.088 / U:0.500 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site