| /* |
| * Copyright (C) 1994 Linus Torvalds |
| * |
| * Pentium III FXSR, SSE support |
| * General FPU state handling cleanups |
| * Gareth Hughes <gareth@valinux.com>, May 2000 |
| * x86-64 work by Andi Kleen 2002 |
| */ |
| |
| #ifndef _ASM_X86_FPU_API_H |
| #define _ASM_X86_FPU_API_H |
| |
| /* |
| * Careful: __kernel_fpu_begin/end() must be called with preempt disabled |
| * and they don't touch the preempt state on their own. |
| * If you enable preemption after __kernel_fpu_begin(), preempt notifier |
| * should call the __kernel_fpu_end() to prevent the kernel/user FPU |
| * state from getting corrupted. KVM for example uses this model. |
| * |
| * All other cases use kernel_fpu_begin/end() which disable preemption |
| * during kernel FPU usage. |
| */ |
| extern void __kernel_fpu_begin(void); |
| extern void __kernel_fpu_end(void); |
| extern void kernel_fpu_begin(void); |
| extern void kernel_fpu_end(void); |
| extern bool irq_fpu_usable(void); |
| |
| /* |
| * Some instructions like VIA's padlock instructions generate a spurious |
| * DNA fault but don't modify SSE registers. And these instructions |
| * get used from interrupt context as well. To prevent these kernel instructions |
| * in interrupt context interacting wrongly with other user/kernel fpu usage, we |
| * should use them only in the context of irq_ts_save/restore() |
| */ |
| extern int irq_ts_save(void); |
| extern void irq_ts_restore(int TS_state); |
| |
| /* |
| * Query the presence of one or more xfeatures. Works on any legacy CPU as well. |
| * |
| * If 'feature_name' is set then put a human-readable description of |
| * the feature there as well - this can be used to print error (or success) |
| * messages. |
| */ |
| extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name); |
| |
| #endif /* _ASM_X86_FPU_API_H */ |
