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

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 1994 Linus Torvalds
   4  *
   5  * Pentium III FXSR, SSE support
   6  * General FPU state handling cleanups
   7  *      Gareth Hughes <gareth@valinux.com>, May 2000
   8  * x86-64 work by Andi Kleen 2002
   9  */
  10
  11 #ifndef _ASM_X86_FPU_API_H
  12 #define _ASM_X86_FPU_API_H
  13
  14 /*
  15  * Careful: __kernel_fpu_begin/end() must be called with preempt disabled
  16  * and they don't touch the preempt state on their own.
  17  * If you enable preemption after __kernel_fpu_begin(), preempt notifier
  18  * should call the __kernel_fpu_end() to prevent the kernel/user FPU
  19  * state from getting corrupted. KVM for example uses this model.
  20  *
  21  * All other cases use kernel_fpu_begin/end() which disable preemption
  22  * during kernel FPU usage.
  23  */
  24 extern void __kernel_fpu_begin(void);
  25 extern void __kernel_fpu_end(void);
  26 extern void kernel_fpu_begin(void);
  27 extern void kernel_fpu_end(void);
  28 extern bool irq_fpu_usable(void);
  29
  30 /*
  31  * Query the presence of one or more xfeatures. Works on any legacy CPU as well.
  32  *
  33  * If 'feature_name' is set then put a human-readable description of
  34  * the feature there as well - this can be used to print error (or success)
  35  * messages.
  36  */
  37 extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name);
  38
  39 #endif /* _ASM_X86_FPU_API_H */