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linux-next/arch/x86/kernel/cpu/scattered.c
Fenghua Yu 6229ad278c x86/xsaves: Detect xsaves/xrstors feature
Detect the xsaveopt, xsavec, xgetbv, and xsaves features in processor extended
state enumberation sub-leaf (eax=0x0d, ecx=1):
Bit 00: XSAVEOPT is available
Bit 01: Supports XSAVEC and the compacted form of XRSTOR if set
Bit 02: Supports XGETBV with ECX = 1 if set
Bit 03: Supports XSAVES/XRSTORS and IA32_XSS if set

The above features are defined in the new word 10 in cpu features.

The IA32_XSS MSR (index DA0H) contains a state-component bitmap that specifies
the state components that software has enabled xsaves and xrstors to manage.
If the bit corresponding to a state component is clear in XCR0 | IA32_XSS,
xsaves and xrstors will not operate on that state component, regardless of
the value of the instruction mask.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1401387164-43416-3-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-29 14:24:28 -07:00

72 lines
1.9 KiB
C

/*
* Routines to identify additional cpu features that are scattered in
* cpuid space.
*/
#include <linux/cpu.h>
#include <asm/pat.h>
#include <asm/processor.h>
#include <asm/apic.h>
struct cpuid_bit {
u16 feature;
u8 reg;
u8 bit;
u32 level;
u32 sub_leaf;
};
enum cpuid_regs {
CR_EAX = 0,
CR_ECX,
CR_EDX,
CR_EBX
};
void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
{
u32 max_level;
u32 regs[4];
const struct cpuid_bit *cb;
static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_DTHERM, CR_EAX, 0, 0x00000006, 0 },
{ X86_FEATURE_IDA, CR_EAX, 1, 0x00000006, 0 },
{ X86_FEATURE_ARAT, CR_EAX, 2, 0x00000006, 0 },
{ X86_FEATURE_PLN, CR_EAX, 4, 0x00000006, 0 },
{ X86_FEATURE_PTS, CR_EAX, 6, 0x00000006, 0 },
{ X86_FEATURE_APERFMPERF, CR_ECX, 0, 0x00000006, 0 },
{ X86_FEATURE_EPB, CR_ECX, 3, 0x00000006, 0 },
{ X86_FEATURE_HW_PSTATE, CR_EDX, 7, 0x80000007, 0 },
{ X86_FEATURE_CPB, CR_EDX, 9, 0x80000007, 0 },
{ X86_FEATURE_PROC_FEEDBACK, CR_EDX,11, 0x80000007, 0 },
{ X86_FEATURE_NPT, CR_EDX, 0, 0x8000000a, 0 },
{ X86_FEATURE_LBRV, CR_EDX, 1, 0x8000000a, 0 },
{ X86_FEATURE_SVML, CR_EDX, 2, 0x8000000a, 0 },
{ X86_FEATURE_NRIPS, CR_EDX, 3, 0x8000000a, 0 },
{ X86_FEATURE_TSCRATEMSR, CR_EDX, 4, 0x8000000a, 0 },
{ X86_FEATURE_VMCBCLEAN, CR_EDX, 5, 0x8000000a, 0 },
{ X86_FEATURE_FLUSHBYASID, CR_EDX, 6, 0x8000000a, 0 },
{ X86_FEATURE_DECODEASSISTS, CR_EDX, 7, 0x8000000a, 0 },
{ X86_FEATURE_PAUSEFILTER, CR_EDX,10, 0x8000000a, 0 },
{ X86_FEATURE_PFTHRESHOLD, CR_EDX,12, 0x8000000a, 0 },
{ 0, 0, 0, 0, 0 }
};
for (cb = cpuid_bits; cb->feature; cb++) {
/* Verify that the level is valid */
max_level = cpuid_eax(cb->level & 0xffff0000);
if (max_level < cb->level ||
max_level > (cb->level | 0xffff))
continue;
cpuid_count(cb->level, cb->sub_leaf, &regs[CR_EAX],
&regs[CR_EBX], &regs[CR_ECX], &regs[CR_EDX]);
if (regs[cb->reg] & (1 << cb->bit))
set_cpu_cap(c, cb->feature);
}
}