diff options
Diffstat (limited to 'arch/x86/include/asm/fpu/api.h')
| -rw-r--r-- | arch/x86/include/asm/fpu/api.h | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index a5aba4ab0224..ed33a14188f6 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -16,14 +16,37 @@ * 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. * A context switch will (and softirq might) save CPU's FPU registers to |