1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */ 2*4882a593Smuzhiyun /* 3*4882a593Smuzhiyun * Copyright (C) 1994 Linus Torvalds 4*4882a593Smuzhiyun * 5*4882a593Smuzhiyun * Pentium III FXSR, SSE support 6*4882a593Smuzhiyun * General FPU state handling cleanups 7*4882a593Smuzhiyun * Gareth Hughes <gareth@valinux.com>, May 2000 8*4882a593Smuzhiyun * x86-64 work by Andi Kleen 2002 9*4882a593Smuzhiyun */ 10*4882a593Smuzhiyun 11*4882a593Smuzhiyun #ifndef _ASM_X86_FPU_API_H 12*4882a593Smuzhiyun #define _ASM_X86_FPU_API_H 13*4882a593Smuzhiyun #include <linux/bottom_half.h> 14*4882a593Smuzhiyun 15*4882a593Smuzhiyun /* 16*4882a593Smuzhiyun * Use kernel_fpu_begin/end() if you intend to use FPU in kernel context. It 17*4882a593Smuzhiyun * disables preemption so be careful if you intend to use it for long periods 18*4882a593Smuzhiyun * of time. 19*4882a593Smuzhiyun * If you intend to use the FPU in irq/softirq you need to check first with 20*4882a593Smuzhiyun * irq_fpu_usable() if it is possible. 21*4882a593Smuzhiyun */ 22*4882a593Smuzhiyun 23*4882a593Smuzhiyun /* Kernel FPU states to initialize in kernel_fpu_begin_mask() */ 24*4882a593Smuzhiyun #define KFPU_387 _BITUL(0) /* 387 state will be initialized */ 25*4882a593Smuzhiyun #define KFPU_MXCSR _BITUL(1) /* MXCSR will be initialized */ 26*4882a593Smuzhiyun 27*4882a593Smuzhiyun extern void kernel_fpu_begin_mask(unsigned int kfpu_mask); 28*4882a593Smuzhiyun extern void kernel_fpu_end(void); 29*4882a593Smuzhiyun extern bool irq_fpu_usable(void); 30*4882a593Smuzhiyun extern void fpregs_mark_activate(void); 31*4882a593Smuzhiyun 32*4882a593Smuzhiyun /* Code that is unaware of kernel_fpu_begin_mask() can use this */ kernel_fpu_begin(void)33*4882a593Smuzhiyunstatic inline void kernel_fpu_begin(void) 34*4882a593Smuzhiyun { 35*4882a593Smuzhiyun kernel_fpu_begin_mask(KFPU_387 | KFPU_MXCSR); 36*4882a593Smuzhiyun } 37*4882a593Smuzhiyun 38*4882a593Smuzhiyun /* 39*4882a593Smuzhiyun * Use fpregs_lock() while editing CPU's FPU registers or fpu->state. 40*4882a593Smuzhiyun * A context switch will (and softirq might) save CPU's FPU registers to 41*4882a593Smuzhiyun * fpu->state and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in 42*4882a593Smuzhiyun * a random state. 43*4882a593Smuzhiyun */ fpregs_lock(void)44*4882a593Smuzhiyunstatic inline void fpregs_lock(void) 45*4882a593Smuzhiyun { 46*4882a593Smuzhiyun preempt_disable(); 47*4882a593Smuzhiyun local_bh_disable(); 48*4882a593Smuzhiyun } 49*4882a593Smuzhiyun fpregs_unlock(void)50*4882a593Smuzhiyunstatic inline void fpregs_unlock(void) 51*4882a593Smuzhiyun { 52*4882a593Smuzhiyun local_bh_enable(); 53*4882a593Smuzhiyun preempt_enable(); 54*4882a593Smuzhiyun } 55*4882a593Smuzhiyun 56*4882a593Smuzhiyun #ifdef CONFIG_X86_DEBUG_FPU 57*4882a593Smuzhiyun extern void fpregs_assert_state_consistent(void); 58*4882a593Smuzhiyun #else fpregs_assert_state_consistent(void)59*4882a593Smuzhiyunstatic inline void fpregs_assert_state_consistent(void) { } 60*4882a593Smuzhiyun #endif 61*4882a593Smuzhiyun 62*4882a593Smuzhiyun /* 63*4882a593Smuzhiyun * Load the task FPU state before returning to userspace. 64*4882a593Smuzhiyun */ 65*4882a593Smuzhiyun extern void switch_fpu_return(void); 66*4882a593Smuzhiyun 67*4882a593Smuzhiyun /* 68*4882a593Smuzhiyun * Query the presence of one or more xfeatures. Works on any legacy CPU as well. 69*4882a593Smuzhiyun * 70*4882a593Smuzhiyun * If 'feature_name' is set then put a human-readable description of 71*4882a593Smuzhiyun * the feature there as well - this can be used to print error (or success) 72*4882a593Smuzhiyun * messages. 73*4882a593Smuzhiyun */ 74*4882a593Smuzhiyun extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name); 75*4882a593Smuzhiyun 76*4882a593Smuzhiyun /* 77*4882a593Smuzhiyun * Tasks that are not using SVA have mm->pasid set to zero to note that they 78*4882a593Smuzhiyun * will not have the valid bit set in MSR_IA32_PASID while they are running. 79*4882a593Smuzhiyun */ 80*4882a593Smuzhiyun #define PASID_DISABLED 0 81*4882a593Smuzhiyun update_pasid(void)82*4882a593Smuzhiyunstatic inline void update_pasid(void) { } 83*4882a593Smuzhiyun 84*4882a593Smuzhiyun #endif /* _ASM_X86_FPU_API_H */ 85