arch/x86/include/asm/fpu/api.h

   1 /*
   2  * Copyright (C) 1994 Linus Torvalds
   3  *
   4  * Pentium III FXSR, SSE support
   5  * General FPU state handling cleanups
   6  *      Gareth Hughes <gareth@valinux.com>, May 2000
   7  * x86-64 work by Andi Kleen 2002
   8  */
   9
  10 #ifndef _ASM_X86_FPU_API_H
  11 #define _ASM_X86_FPU_API_H
  12
  13 /*
  14  * Careful: __kernel_fpu_begin/end() must be called with preempt disabled
  15  * and they don't touch the preempt state on their own.
  16  * If you enable preemption after __kernel_fpu_begin(), preempt notifier
  17  * should call the __kernel_fpu_end() to prevent the kernel/user FPU
  18  * state from getting corrupted. KVM for example uses this model.
  19  *
  20  * All other cases use kernel_fpu_begin/end() which disable preemption
  21  * during kernel FPU usage.
  22  */
  23 extern void __kernel_fpu_begin(void);
  24 extern void __kernel_fpu_end(void);
  25 extern void kernel_fpu_begin(void);
  26 extern void kernel_fpu_end(void);
  27 extern bool irq_fpu_usable(void);
  28
  29 /*
  30  * Query the presence of one or more xfeatures. Works on any legacy CPU as well.
  31  *
  32  * If 'feature_name' is set then put a human-readable description of
  33  * the feature there as well - this can be used to print error (or success)
  34  * messages.
  35  */
  36 extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name);
  37
  38 #endif /* _ASM_X86_FPU_API_H */