tree ada2b711139dfec0ba6bd820e7840138af4d5bfa
parent d3608b5681d238605b7da6be62244e803e24c649
author H. Peter Anvin <hpa@zytor.com> 1280298592 -0700
committer H. Peter Anvin <hpa@zytor.com> 1280298592 -0700

x86, asm: Clean up and simplify set_64bit()

Clean up and simplify set_64bit().  This code is quite old (1.3.11)
and contains a fair bit of auxilliary machinery that current versions
of gcc handle just fine automatically.  Worse, the auxilliary
machinery can actually cause an unnecessary spill to memory.

Furthermore, the loading of the old value inside the loop in the
32-bit case is unnecessary: if the value doesn't match, the CMPXCHG8B
instruction will already have loaded the "new previous" value for us.

Clean up the comment, too, and remove page references to obsolete
versions of the Intel SDM.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <tip-*@vger.kernel.org>