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 */ 40