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/processor.h> 12 #include <asm/ptrace.h> 13 #include <asm/csr.h> 14 15 #ifdef CONFIG_FPU 16 extern void __fstate_save(struct task_struct *save_to); 17 extern void __fstate_restore(struct task_struct *restore_from); 18 19 static inline void __fstate_clean(struct pt_regs *regs) 20 { 21 regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN; 22 } 23 24 static inline void fstate_off(struct task_struct *task, 25 struct pt_regs *regs) 26 { 27 regs->status = (regs->status & ~SR_FS) | SR_FS_OFF; 28 } 29 30 static inline void fstate_save(struct task_struct *task, 31 struct pt_regs *regs) 32 { 33 if ((regs->status & SR_FS) == SR_FS_DIRTY) { 34 __fstate_save(task); 35 __fstate_clean(regs); 36 } 37 } 38 39 static inline void fstate_restore(struct task_struct *task, 40 struct pt_regs *regs) 41 { 42 if ((regs->status & SR_FS) != SR_FS_OFF) { 43 __fstate_restore(task); 44 __fstate_clean(regs); 45 } 46 } 47 48 static inline void __switch_to_aux(struct task_struct *prev, 49 struct task_struct *next) 50 { 51 struct pt_regs *regs; 52 53 regs = task_pt_regs(prev); 54 if (unlikely(regs->status & SR_SD)) 55 fstate_save(prev, regs); 56 fstate_restore(next, task_pt_regs(next)); 57 } 58 59 extern struct static_key_false cpu_hwcap_fpu; 60 static __always_inline bool has_fpu(void) 61 { 62 return static_branch_likely(&cpu_hwcap_fpu); 63 } 64 #else 65 static __always_inline bool has_fpu(void) { return false; } 66 #define fstate_save(task, regs) do { } while (0) 67 #define fstate_restore(task, regs) do { } while (0) 68 #define __switch_to_aux(__prev, __next) do { } while (0) 69 #endif 70 71 extern struct task_struct *__switch_to(struct task_struct *, 72 struct task_struct *); 73 74 #define switch_to(prev, next, last) \ 75 do { \ 76 struct task_struct *__prev = (prev); \ 77 struct task_struct *__next = (next); \ 78 if (has_fpu()) \ 79 __switch_to_aux(__prev, __next); \ 80 ((last) = __switch_to(__prev, __next)); \ 81 } while (0) 82 83 #endif /* _ASM_RISCV_SWITCH_TO_H */ 84