1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2012 Regents of the University of California 4 */ 5 6 #ifndef _ASM_RISCV_SWITCH_TO_H 7 #define _ASM_RISCV_SWITCH_TO_H 8 9 #include <linux/jump_label.h> 10 #include <linux/sched/task_stack.h> 11 #include <asm/vector.h> 12 #include <asm/cpufeature.h> 13 #include <asm/processor.h> 14 #include <asm/ptrace.h> 15 #include <asm/csr.h> 16 17 #ifdef CONFIG_FPU 18 extern void __fstate_save(struct task_struct *save_to); 19 extern void __fstate_restore(struct task_struct *restore_from); 20 21 static inline void __fstate_clean(struct pt_regs *regs) 22 { 23 regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN; 24 } 25 26 static inline void fstate_off(struct task_struct *task, 27 struct pt_regs *regs) 28 { 29 regs->status = (regs->status & ~SR_FS) | SR_FS_OFF; 30 } 31 32 static inline void fstate_save(struct task_struct *task, 33 struct pt_regs *regs) 34 { 35 if ((regs->status & SR_FS) == SR_FS_DIRTY) { 36 __fstate_save(task); 37 __fstate_clean(regs); 38 } 39 } 40 41 static inline void fstate_restore(struct task_struct *task, 42 struct pt_regs *regs) 43 { 44 if ((regs->status & SR_FS) != SR_FS_OFF) { 45 __fstate_restore(task); 46 __fstate_clean(regs); 47 } 48 } 49 50 static inline void __switch_to_fpu(struct task_struct *prev, 51 struct task_struct *next) 52 { 53 struct pt_regs *regs; 54 55 regs = task_pt_regs(prev); 56 if (unlikely(regs->status & SR_SD)) 57 fstate_save(prev, regs); 58 fstate_restore(next, task_pt_regs(next)); 59 } 60 61 static __always_inline bool has_fpu(void) 62 { 63 return riscv_has_extension_likely(RISCV_ISA_EXT_f) || 64 riscv_has_extension_likely(RISCV_ISA_EXT_d); 65 } 66 #else 67 static __always_inline bool has_fpu(void) { return false; } 68 #define fstate_save(task, regs) do { } while (0) 69 #define fstate_restore(task, regs) do { } while (0) 70 #define __switch_to_fpu(__prev, __next) do { } while (0) 71 #endif 72 73 extern struct task_struct *__switch_to(struct task_struct *, 74 struct task_struct *); 75 76 #define switch_to(prev, next, last) \ 77 do { \ 78 struct task_struct *__prev = (prev); \ 79 struct task_struct *__next = (next); \ 80 if (has_fpu()) \ 81 __switch_to_fpu(__prev, __next); \ 82 if (has_vector()) \ 83 __switch_to_vector(__prev, __next); \ 84 ((last) = __switch_to(__prev, __next)); \ 85 } while (0) 86 87 #endif /* _ASM_RISCV_SWITCH_TO_H */ 88