tree 06c29cda09e204d3b0b5b3d9a2a97bda0b4e340d
parent 250825008f1f94887bc039e9227a8adfb5ba366e
author Avi Kivity <avi@redhat.com> 1273135545 +0300
committer H. Peter Anvin <hpa@zytor.com> 1273513173 -0700

x86: Eliminate TS_XSAVE

The fpu code currently uses current->thread_info->status & TS_XSAVE as
a way to distinguish between XSAVE capable processors and older processors.
The decision is not really task specific; instead we use the task status to
avoid a global memory reference - the value should be the same across all
threads.

Eliminate this tie-in into the task structure by using an alternative
instruction keyed off the XSAVE cpu feature; this results in shorter and
faster code, without introducing a global memory reference.

[ hpa: in the future, this probably should use an asm jmp ]

Signed-off-by: Avi Kivity <avi@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1273135546-29690-2-git-send-email-avi@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>