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| author |   H.J. Lu <hjl.tools@gmail.com> | 2013-07-26 09:11:56 -0700 |
|---|---|---|
| committer |   H. Peter Anvin <hpa@linux.intel.com> | 2013-07-26 09:11:56 -0700 |
| commit | eaa5a990191d204ba0f9d35dbe5505ec2cdd1460 (patch) | |
| tree | c6ccf3fffc6f575e322ba84ed1de80cda14f49a3 /tools/perf/scripts/python/export-to-postgresql.py | |
| parent | x86/iommu/vt-d: Expand interrupt remapping quirk to cover x58 chipset (diff) | |
| download | linux-dev-eaa5a990191d204ba0f9d35dbe5505ec2cdd1460.tar.xz linux-dev-eaa5a990191d204ba0f9d35dbe5505ec2cdd1460.zip | |
x86, fpu: correct the asm constraints for fxsave, unbreak mxcsr.daz
GCC will optimize mxcsr_feature_mask_init in arch/x86/kernel/i387.c:
memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));
asm volatile("fxsave %0" : : "m" (fx_scratch));
mask = fx_scratch.mxcsr_mask;
if (mask == 0)
mask = 0x0000ffbf;
to
memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));
asm volatile("fxsave %0" : : "m" (fx_scratch));
mask = 0x0000ffbf;
since asm statement doesn’t say it will update fx_scratch. As the
result, the DAZ bit will be cleared. This patch fixes it. This bug
dates back to at least kernel 2.6.12.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>
Diffstat (limited to 'tools/perf/scripts/python/export-to-postgresql.py')
0 files changed, 0 insertions, 0 deletions