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x86, xsave: Track the offset, size of state in the xsave layout 

Subleaves of the cpuid vector 0xd provides the offset and size of different
feature state that are managed by the xsave/xrstor. Track this for the upcoming
usage during signal handling.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100719230205.262987929@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Suresh Siddha 2010-07-19 16:05:48 -07:00 committed by H. Peter Anvin
parent 5734f62b66
commit a1488f8bf4
1 changed files with 29 additions and 0 deletions
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29
arch/x86/kernel/xsave.c
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@ -21,6 +21,8 @@ struct _fpx_sw_bytes fx_sw_reserved;
struct _fpx_sw_bytes fx_sw_reserved_ia32;
#endif
static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
/*
* Check for the presence of extended state information in the
* user fpstate pointer in the sigcontext.
@ -301,6 +303,31 @@ void __cpuinit xsave_init(void)
xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
}
/*
* Record the offsets and sizes of different state managed by the xsave
* memory layout.
*/
static void setup_xstate_features(void)
{
int eax, ebx, ecx, edx, leaf = 0x2;
xstate_features = fls64(pcntxt_mask);
xstate_offsets = alloc_bootmem(xstate_features * sizeof(int));
xstate_sizes = alloc_bootmem(xstate_features * sizeof(int));
do {
cpuid_count(0xd, leaf, &eax, &ebx, &ecx, &edx);
if (eax == 0)
break;
xstate_offsets[leaf] = ebx;
xstate_sizes[leaf] = eax;
leaf++;
} while (1);
}
/*
* setup the xstate image representing the init state
*/
@ -308,6 +335,8 @@ static void __init setup_xstate_init(void)
{
init_xstate_buf = alloc_bootmem(xstate_size);
init_xstate_buf->i387.mxcsr = MXCSR_DEFAULT;
setup_xstate_features();
}
/*