[PATCH v2] Fix atomic_full_barrier on x86 and x86_64.

[Torvald Riegel]

This is a revision of
https://sourceware.org/ml/libc-alpha/2014-10/msg00702.

This fixes BZ #17403 by defining atomic_full_barrier,
atomic_read_barrier, and atomic_write_barrier on x86 and x86_64.  A full
barrier is implemented through an atomic idempotent modification to the
stack and not through using mfence because the latter can supposedly be
somewhat slower due to having to provide stronger guarantees wrt
self-modifying code, for example.

Tested on x86_64-linux.

H.J., is this OK for x86 and x32?


2015-06-23  Torvald Riegel  <triegel@redhat.com>

	[BZ #17403]
	* sysdeps/x86_64/bits/atomic.h: (atomic_full_barrier,
	atomic_read_barrier, atomic_write_barrier): Define.
	* sysdeps/i386/i486/bits/atomic.h (atomic_full_barrier,
	atomic_read_barrier, atomic_write_barrier): Define.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: atomic-fullbarrier.patch
Type: text/x-patch
Size: 4227 bytes
Desc: not available
URL: <http://sourceware.org/pipermail/libc-alpha/attachments/20150623/33aa0d60/attachment.bin>