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| author | Avi Kivity <avi@redhat.com> | 2010-05-06 11:45:45 +0300 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2010-05-10 10:39:33 -0700 |
| commit | c9ad488289144ae5ef53b012e15895ef1f5e4bb6 (patch) | |
| tree | 06c29cda09e204d3b0b5b3d9a2a97bda0b4e340d /arch/x86/kernel/xsave.c | |
| parent | 250825008f1f94887bc039e9227a8adfb5ba366e (diff) | |
| download | linux-c9ad488289144ae5ef53b012e15895ef1f5e4bb6.tar.gz linux-c9ad488289144ae5ef53b012e15895ef1f5e4bb6.tar.bz2 linux-c9ad488289144ae5ef53b012e15895ef1f5e4bb6.zip | |
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>
Diffstat (limited to 'arch/x86/kernel/xsave.c')
| -rw-r--r-- | arch/x86/kernel/xsave.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 782c3a362ec6..c1b0a11033a2 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -99,7 +99,7 @@ int save_i387_xstate(void __user *buf) if (err) return err; - if (task_thread_info(tsk)->status & TS_XSAVE) + if (use_xsave()) err = xsave_user(buf); else err = fxsave_user(buf); @@ -116,7 +116,7 @@ int save_i387_xstate(void __user *buf) clear_used_math(); /* trigger finit */ - if (task_thread_info(tsk)->status & TS_XSAVE) { + if (use_xsave()) { struct _fpstate __user *fx = buf; struct _xstate __user *x = buf; u64 xstate_bv; @@ -225,7 +225,7 @@ int restore_i387_xstate(void __user *buf) clts(); task_thread_info(current)->status |= TS_USEDFPU; } - if (task_thread_info(tsk)->status & TS_XSAVE) + if (use_xsave()) err = restore_user_xstate(buf); else err = fxrstor_checking((__force struct i387_fxsave_struct *) |