Re: [announce] [patch] NX (No eXecute) support for x86, 2.6.7-rc2-bk2

[Ulrich Drepper]

Ingo Molnar wrote:
> gcc's
> PT_GNU_STACK mechanism is very conservative - e.g. if an application
> does an asm() then gcc assumes that it might rely on stack executability
> and emits the X flag. 

Actually, this isn't the case.  asm() alone don't trigger this.  There
are far too many of them in use.  And there never has been a reported
problem.  Only trampolines etc cause gcc to automatically request the X
flag to be set.  In case an asm() indeed causes problems the user can
pass the --execstack option to the linker.

It's all explained in

  http://people.redhat.com/drepper/nonselsec.pdf

-- 
â Ulrich Drepper â Red Hat, Inc. â 444 Castro St â Mountain View, CA â
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