diff options
Diffstat (limited to 'arch/x86/include/asm/fpu/api.h')
| -rw-r--r-- | arch/x86/include/asm/fpu/api.h | 120 |
1 files changed, 112 insertions, 8 deletions
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index b774c52e5411..503a577814b2 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -12,34 +12,74 @@ #define _ASM_X86_FPU_API_H #include <linux/bottom_half.h> +#include <asm/fpu/types.h> + /* * Use kernel_fpu_begin/end() if you intend to use FPU in kernel context. It * disables preemption so be careful if you intend to use it for long periods * of time. - * If you intend to use the FPU in softirq you need to check first with + * If you intend to use the FPU in irq/softirq you need to check first with * irq_fpu_usable() if it is possible. */ -extern void kernel_fpu_begin(void); + +/* Kernel FPU states to initialize in kernel_fpu_begin_mask() */ +#define KFPU_387 _BITUL(0) /* 387 state will be initialized */ +#define KFPU_MXCSR _BITUL(1) /* MXCSR will be initialized */ + +extern void kernel_fpu_begin_mask(unsigned int kfpu_mask); extern void kernel_fpu_end(void); extern bool irq_fpu_usable(void); extern void fpregs_mark_activate(void); +/* Code that is unaware of kernel_fpu_begin_mask() can use this */ +static inline void kernel_fpu_begin(void) +{ +#ifdef CONFIG_X86_64 + /* + * Any 64-bit code that uses 387 instructions must explicitly request + * KFPU_387. + */ + kernel_fpu_begin_mask(KFPU_MXCSR); +#else + /* + * 32-bit kernel code may use 387 operations as well as SSE2, etc, + * as long as it checks that the CPU has the required capability. + */ + kernel_fpu_begin_mask(KFPU_387 | KFPU_MXCSR); +#endif +} + /* - * Use fpregs_lock() while editing CPU's FPU registers or fpu->state. + * Use fpregs_lock() while editing CPU's FPU registers or fpu->fpstate. * A context switch will (and softirq might) save CPU's FPU registers to - * fpu->state and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in + * fpu->fpstate.regs and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in * a random state. + * + * local_bh_disable() protects against both preemption and soft interrupts + * on !RT kernels. + * + * On RT kernels local_bh_disable() is not sufficient because it only + * serializes soft interrupt related sections via a local lock, but stays + * preemptible. Disabling preemption is the right choice here as bottom + * half processing is always in thread context on RT kernels so it + * implicitly prevents bottom half processing as well. + * + * Disabling preemption also serializes against kernel_fpu_begin(). */ static inline void fpregs_lock(void) { - preempt_disable(); - local_bh_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_disable(); + else + preempt_disable(); } static inline void fpregs_unlock(void) { - local_bh_enable(); - preempt_enable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_enable(); + else + preempt_enable(); } #ifdef CONFIG_X86_DEBUG_FPU @@ -62,4 +102,68 @@ extern void switch_fpu_return(void); */ extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name); +/* Trap handling */ +extern int fpu__exception_code(struct fpu *fpu, int trap_nr); +extern void fpu_sync_fpstate(struct fpu *fpu); +extern void fpu_reset_from_exception_fixup(void); + +/* Boot, hotplug and resume */ +extern void fpu__init_cpu(void); +extern void fpu__init_system(struct cpuinfo_x86 *c); +extern void fpu__init_check_bugs(void); +extern void fpu__resume_cpu(void); + +#ifdef CONFIG_MATH_EMULATION +extern void fpstate_init_soft(struct swregs_state *soft); +#else +static inline void fpstate_init_soft(struct swregs_state *soft) {} +#endif + +/* State tracking */ +DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx); + +/* Process cleanup */ +#ifdef CONFIG_X86_64 +extern void fpstate_free(struct fpu *fpu); +#else +static inline void fpstate_free(struct fpu *fpu) { } +#endif + +/* fpstate-related functions which are exported to KVM */ +extern void fpstate_clear_xstate_component(struct fpstate *fps, unsigned int xfeature); + +extern u64 xstate_get_guest_group_perm(void); + +/* KVM specific functions */ +extern bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu); +extern void fpu_free_guest_fpstate(struct fpu_guest *gfpu); +extern int fpu_swap_kvm_fpstate(struct fpu_guest *gfpu, bool enter_guest); +extern int fpu_enable_guest_xfd_features(struct fpu_guest *guest_fpu, u64 xfeatures); + +#ifdef CONFIG_X86_64 +extern void fpu_update_guest_xfd(struct fpu_guest *guest_fpu, u64 xfd); +extern void fpu_sync_guest_vmexit_xfd_state(void); +#else +static inline void fpu_update_guest_xfd(struct fpu_guest *guest_fpu, u64 xfd) { } +static inline void fpu_sync_guest_vmexit_xfd_state(void) { } +#endif + +extern void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf, unsigned int size, u32 pkru); +extern int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, u64 xcr0, u32 *vpkru); + +static inline void fpstate_set_confidential(struct fpu_guest *gfpu) +{ + gfpu->fpstate->is_confidential = true; +} + +static inline bool fpstate_is_confidential(struct fpu_guest *gfpu) +{ + return gfpu->fpstate->is_confidential; +} + +/* prctl */ +extern long fpu_xstate_prctl(int option, unsigned long arg2); + +extern void fpu_idle_fpregs(void); + #endif /* _ASM_X86_FPU_API_H */ |