From 212b02125f3725127148475059a70031bd031bdb Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Thu, 6 Sep 2012 15:05:18 -0700 Subject: [PATCH] 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 Link: http://lkml.kernel.org/r/1347300665-6209-3-git-send-email-suresh.b.siddha@intel.com Signed-off-by: H. Peter Anvin --- Documentation/kernel-parameters.txt | 2 +- arch/x86/include/asm/cpufeature.h | 1 + arch/x86/kernel/xsave.c | 3 +++ 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 741d064fdc6a..e8f7faaa4571 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 5dd2b473ccff..0debdb518440 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 c0afd2c43761..e99f75439f6d 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); } -- 2.39.2