From 0a265375028b241a9173b7c569dd2368ba97fcd4 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Wed, 2 Sep 2015 16:31:24 -0700 Subject: [PATCH] x86/fpu: Move XSAVE-disabling code to a helper When we want to _completely_ disable XSAVE support as far as the kernel is concerned, we have a big set of feature flags to clear. We currently only do this in cases where the user asks for it to be disabled, but we are about to expand the places where we do it to handle errors too. Move the code in to xstate.c, and put it in the xstate.h header. We will use it in the next patch too. Signed-off-by: Dave Hansen Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tim Chen Cc: dave@sr71.net Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20150902233124.EA9A70E5@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/fpu/xstate.h | 1 + arch/x86/kernel/fpu/init.c | 12 +----------- arch/x86/kernel/fpu/xstate.c | 19 +++++++++++++++++++ 3 files changed, 21 insertions(+), 11 deletions(-) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 4656b25bb9a7..d5a9b736553c 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -40,6 +40,7 @@ extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS]; extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask); +void fpu__xstate_clear_all_cpu_caps(void); void *get_xsave_addr(struct xregs_state *xsave, int xstate); const void *get_xsave_field_ptr(int xstate_field); diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index d14e9ac3235a..0a250afc6cdf 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -354,17 +354,7 @@ static int __init x86_noxsave_setup(char *s) if (strlen(s)) return 0; - setup_clear_cpu_cap(X86_FEATURE_XSAVE); - setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT); - setup_clear_cpu_cap(X86_FEATURE_XSAVEC); - setup_clear_cpu_cap(X86_FEATURE_XSAVES); - setup_clear_cpu_cap(X86_FEATURE_AVX); - setup_clear_cpu_cap(X86_FEATURE_AVX2); - setup_clear_cpu_cap(X86_FEATURE_AVX512F); - setup_clear_cpu_cap(X86_FEATURE_AVX512PF); - setup_clear_cpu_cap(X86_FEATURE_AVX512ER); - setup_clear_cpu_cap(X86_FEATURE_AVX512CD); - setup_clear_cpu_cap(X86_FEATURE_MPX); + fpu__xstate_clear_all_cpu_caps(); return 1; } diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index b790dcbd3d2a..2ada11c0f8d7 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -38,6 +38,25 @@ static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8]; /* The number of supported xfeatures in xfeatures_mask: */ static unsigned int xfeatures_nr; +/* + * Clear all of the X86_FEATURE_* bits that are unavailable + * when the CPU has no XSAVE support. + */ +void fpu__xstate_clear_all_cpu_caps(void) +{ + setup_clear_cpu_cap(X86_FEATURE_XSAVE); + setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT); + setup_clear_cpu_cap(X86_FEATURE_XSAVEC); + setup_clear_cpu_cap(X86_FEATURE_XSAVES); + setup_clear_cpu_cap(X86_FEATURE_AVX); + setup_clear_cpu_cap(X86_FEATURE_AVX2); + setup_clear_cpu_cap(X86_FEATURE_AVX512F); + setup_clear_cpu_cap(X86_FEATURE_AVX512PF); + setup_clear_cpu_cap(X86_FEATURE_AVX512ER); + setup_clear_cpu_cap(X86_FEATURE_AVX512CD); + setup_clear_cpu_cap(X86_FEATURE_MPX); +} + /* * Return whether the system supports a given xfeature. *