x86: Eliminate TS_XSAVE

Browse source

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>

...

This commit is contained in:

Avi Kivity 2010-05-06 11:45:45 +03:00 • committed by H. Peter Anvin

parent 250825008f

commit c9ad488289

5 changed files with 21 additions and 16 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

20

arch/x86/include/asm/i387.h

View file

1

arch/x86/include/asm/thread_info.h

View file

5

arch/x86/kernel/cpu/common.c

View file

5

arch/x86/kernel/i387.c

View file

6

arch/x86/kernel/xsave.c

View file