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/*
* 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 */
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