From 55cc4678b7ee2edd3e6a9411250530eb871bc61d Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 25 Apr 2015 06:26:36 +0200 Subject: [PATCH] x86/fpu: Make the system/cpu init distinction clear in the xstate code as well Rename existing xstate init functions along the system/cpu init principles: fpu__init_system_xstate(): called once per system bootup fpu__init_cpu_xstate(): called per CPU onlining Also make the fpu__init_cpu_xstate() early code invariant: if xfeatures_mask is not set yet then don't crash but return. Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- arch/x86/include/asm/fpu/internal.h | 3 +++ arch/x86/kernel/fpu/xsave.c | 22 ++++++++++++++-------- 2 files changed, 17 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 19b7cdf73efd..71d44be5acb1 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -39,6 +39,9 @@ extern unsigned int mxcsr_feature_mask; extern void fpu__cpu_init(void); extern void eager_fpu_init(void); +extern void fpu__init_system_xstate(void); +extern void fpu__init_cpu_xstate(void); + DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx); extern void convert_from_fxsr(struct user_i387_ia32_struct *env, diff --git a/arch/x86/kernel/fpu/xsave.c b/arch/x86/kernel/fpu/xsave.c index 45130ba6f328..961c25850c7f 100644 --- a/arch/x86/kernel/fpu/xsave.c +++ b/arch/x86/kernel/fpu/xsave.c @@ -460,10 +460,14 @@ static void prepare_fx_sw_frame(void) } /* - * Enable the extended processor state save/restore feature + * Enable the extended processor state save/restore feature. + * Called once per CPU onlining. */ -static inline void xstate_enable(void) +void fpu__init_cpu_xstate(void) { + if (!xfeatures_mask) + return; + cr4_set_bits(X86_CR4_OSXSAVE); xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask); } @@ -640,11 +644,12 @@ static void __init init_xstate_size(void) /* * Enable and initialize the xsave feature. + * Called once per system bootup. * * ( Not marked __init because of false positive section warnings * generated by xsave_init(). ) */ -static void /* __init */ xstate_enable_boot_cpu(void) +void fpu__init_system_xstate(void) { unsigned int eax, ebx, ecx, edx; @@ -666,7 +671,8 @@ static void /* __init */ xstate_enable_boot_cpu(void) */ xfeatures_mask = xfeatures_mask & XCNTXT_MASK; - xstate_enable(); + /* Enable xstate instructions to be able to continue with initialization: */ + fpu__init_cpu_xstate(); /* * Recompute the context size for enabled features @@ -698,8 +704,8 @@ static void /* __init */ xstate_enable_boot_cpu(void) } /* - * For the very first instance, this calls xstate_enable_boot_cpu(); - * for all subsequent instances, this calls xstate_enable(). + * For the very first instance, this calls fpu__init_system_xstate(); + * for all subsequent instances, this calls fpu__init_cpu_xstate(). */ void xsave_init(void) { @@ -715,9 +721,9 @@ void xsave_init(void) if (on_boot_cpu) { on_boot_cpu = 0; - xstate_enable_boot_cpu(); + fpu__init_system_xstate(); } else { - xstate_enable(); + fpu__init_cpu_xstate(); } } -- 2.20.1