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| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2012-09-06 22:05:18 (GMT) |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2012-09-18 22:52:23 (GMT) |
| commit | 212b02125f3725127148475059a70031bd031bdb (patch) | |
| tree | 9505ae1f2d35ee9c803c0d3e64451b41db9ccb8b | |
| parent | 5d2bd7009f306c82afddd1ca4d9763ad8473c216 (diff) | |
| download | linux-212b02125f3725127148475059a70031bd031bdb.tar.xz | |
x86, fpu: enable eagerfpu by default for xsaveopt
xsaveopt/xrstor support optimized state save/restore by tracking the
INIT state and MODIFIED state during context-switch.
Enable eagerfpu by default for processors supporting xsaveopt.
Can be disabled by passing "eagerfpu=off" boot parameter.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1347300665-6209-3-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| -rw-r--r-- | Documentation/kernel-parameters.txt | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/cpufeature.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/xsave.c | 3 |
3 files changed, 5 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 741d064..e8f7faa 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1834,7 +1834,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. enabling legacy floating-point and sse state. eagerfpu= [X86] - on enable eager fpu restore + on enable eager fpu restore (default for xsaveopt) off disable eager fpu restore nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 5dd2b47..0debdb5 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -300,6 +300,7 @@ extern const char * const x86_power_flags[32]; #define cpu_has_xmm4_2 boot_cpu_has(X86_FEATURE_XMM4_2) #define cpu_has_x2apic boot_cpu_has(X86_FEATURE_X2APIC) #define cpu_has_xsave boot_cpu_has(X86_FEATURE_XSAVE) +#define cpu_has_xsaveopt boot_cpu_has(X86_FEATURE_XSAVEOPT) #define cpu_has_osxsave boot_cpu_has(X86_FEATURE_OSXSAVE) #define cpu_has_hypervisor boot_cpu_has(X86_FEATURE_HYPERVISOR) #define cpu_has_pclmulqdq boot_cpu_has(X86_FEATURE_PCLMULQDQ) diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index c0afd2c..e99f754 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -557,6 +557,9 @@ static void __init xstate_enable_boot_cpu(void) prepare_fx_sw_frame(); setup_init_fpu_buf(); + if (cpu_has_xsaveopt && !disable_eagerfpu) + setup_force_cpu_cap(X86_FEATURE_EAGER_FPU); + pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x\n", pcntxt_mask, xstate_size); } |