1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Author: Huacai Chen <chenhuacai@loongson.cn> 4 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited 5 */ 6 #ifndef _ASM_FPU_H 7 #define _ASM_FPU_H 8 9 #include <linux/sched.h> 10 #include <linux/sched/task_stack.h> 11 #include <linux/ptrace.h> 12 #include <linux/thread_info.h> 13 #include <linux/bitops.h> 14 15 #include <asm/cpu.h> 16 #include <asm/cpu-features.h> 17 #include <asm/current.h> 18 #include <asm/loongarch.h> 19 #include <asm/processor.h> 20 #include <asm/ptrace.h> 21 22 struct sigcontext; 23 24 extern void kernel_fpu_begin(void); 25 extern void kernel_fpu_end(void); 26 27 extern void _init_fpu(unsigned int); 28 extern void _save_fp(struct loongarch_fpu *); 29 extern void _restore_fp(struct loongarch_fpu *); 30 31 /* 32 * Mask the FCSR Cause bits according to the Enable bits, observing 33 * that Unimplemented is always enabled. 34 */ 35 static inline unsigned long mask_fcsr_x(unsigned long fcsr) 36 { 37 return fcsr & ((fcsr & FPU_CSR_ALL_E) << 38 (ffs(FPU_CSR_ALL_X) - ffs(FPU_CSR_ALL_E))); 39 } 40 41 static inline int is_fp_enabled(void) 42 { 43 return (csr_read32(LOONGARCH_CSR_EUEN) & CSR_EUEN_FPEN) ? 44 1 : 0; 45 } 46 47 #define enable_fpu() set_csr_euen(CSR_EUEN_FPEN) 48 49 #define disable_fpu() clear_csr_euen(CSR_EUEN_FPEN) 50 51 #define clear_fpu_owner() clear_thread_flag(TIF_USEDFPU) 52 53 static inline int is_fpu_owner(void) 54 { 55 return test_thread_flag(TIF_USEDFPU); 56 } 57 58 static inline void __own_fpu(void) 59 { 60 enable_fpu(); 61 set_thread_flag(TIF_USEDFPU); 62 KSTK_EUEN(current) |= CSR_EUEN_FPEN; 63 } 64 65 static inline void own_fpu_inatomic(int restore) 66 { 67 if (cpu_has_fpu && !is_fpu_owner()) { 68 __own_fpu(); 69 if (restore) 70 _restore_fp(¤t->thread.fpu); 71 } 72 } 73 74 static inline void own_fpu(int restore) 75 { 76 preempt_disable(); 77 own_fpu_inatomic(restore); 78 preempt_enable(); 79 } 80 81 static inline void lose_fpu_inatomic(int save, struct task_struct *tsk) 82 { 83 if (is_fpu_owner()) { 84 if (save) 85 _save_fp(&tsk->thread.fpu); 86 disable_fpu(); 87 clear_tsk_thread_flag(tsk, TIF_USEDFPU); 88 } 89 KSTK_EUEN(tsk) &= ~(CSR_EUEN_FPEN | CSR_EUEN_LSXEN | CSR_EUEN_LASXEN); 90 } 91 92 static inline void lose_fpu(int save) 93 { 94 preempt_disable(); 95 lose_fpu_inatomic(save, current); 96 preempt_enable(); 97 } 98 99 static inline void init_fpu(void) 100 { 101 unsigned int fcsr = current->thread.fpu.fcsr; 102 103 __own_fpu(); 104 _init_fpu(fcsr); 105 set_used_math(); 106 } 107 108 static inline void save_fp(struct task_struct *tsk) 109 { 110 if (cpu_has_fpu) 111 _save_fp(&tsk->thread.fpu); 112 } 113 114 static inline void restore_fp(struct task_struct *tsk) 115 { 116 if (cpu_has_fpu) 117 _restore_fp(&tsk->thread.fpu); 118 } 119 120 static inline union fpureg *get_fpu_regs(struct task_struct *tsk) 121 { 122 if (tsk == current) { 123 preempt_disable(); 124 if (is_fpu_owner()) 125 _save_fp(¤t->thread.fpu); 126 preempt_enable(); 127 } 128 129 return tsk->thread.fpu.fpr; 130 } 131 132 #endif /* _ASM_FPU_H */ 133