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authorAvi Kivity <avi@redhat.com>2010-05-06 11:45:45 +0300
committerH. Peter Anvin <hpa@zytor.com>2010-05-10 10:39:33 -0700
commitc9ad488289144ae5ef53b012e15895ef1f5e4bb6 (patch)
tree06c29cda09e204d3b0b5b3d9a2a97bda0b4e340d /arch/x86/kernel/i387.c
parent250825008f1f94887bc039e9227a8adfb5ba366e (diff)
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/i387.c')
-rw-r--r--arch/x86/kernel/i387.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 54c31c285488..14ca1dc7a703 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -102,10 +102,7 @@ void __cpuinit fpu_init(void)
mxcsr_feature_mask_init();
/* clean state in init */
- if (cpu_has_xsave)
- current_thread_info()->status = TS_XSAVE;
- else
- current_thread_info()->status = 0;
+ current_thread_info()->status = 0;
clear_used_math();
}
#endif /* CONFIG_X86_64 */