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x86/xsaves: Change compacted format xsave area header

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The XSAVE area header is changed to support both compacted format and
standard format of xsave area.

The XSAVE header of an xsave area comprises the 64 bytes starting at offset
512 from the area base address:

- Bytes 7:0 of the xsave header is a state-component bitmap called
  xstate_bv. It identifies the state components in the xsave area.

- Bytes 15:8 of the xsave header is a state-component bitmap called
  xcomp_bv. It is used as follows:
  - xcomp_bv[63] indicates the format of the extended region of
    the xsave area. If it is clear, the standard format is used.
    If it is set, the compacted format is used.
  - xcomp_bv[62:0] indicate which features (starting at feature 2)
    have space allocated for them in the compacted format.

- Bytes 63:16 of the xsave header are reserved.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1401387164-43416-6-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Fenghua Yu 2014-05-29 11:12:33 -07:00 committed by H. Peter Anvin
parent 5b3e83f46a
commit 0b29643a58
1 changed files with 2 additions and 2 deletions
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4
arch/x86/include/asm/processor.h
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@ -386,8 +386,8 @@ struct bndcsr_struct {
struct xsave_hdr_struct {
u64 xstate_bv;
u64 reserved1[2];
u64 reserved2[5];
u64 xcomp_bv;
u64 reserved[6];
} __attribute__((packed));
struct xsave_struct {