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/sched/task_stack.h> 10 #include <asm/processor.h> 11 #include <asm/ptrace.h> 12 #include <asm/csr.h> 13 14 #ifdef CONFIG_FPU 15 extern void __fstate_save(struct task_struct *save_to); 16 extern void __fstate_restore(struct task_struct *restore_from); 17 18 static inline void __fstate_clean(struct pt_regs *regs) 19 { 20 regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN; 21 } 22 23 static inline void fstate_off(struct task_struct *task, 24 struct pt_regs *regs) 25 { 26 regs->status = (regs->status & ~SR_FS) | SR_FS_OFF; 27 } 28 29 static inline void fstate_save(struct task_struct *task, 30 struct pt_regs *regs) 31 { 32 if ((regs->status & SR_FS) == SR_FS_DIRTY) { 33 __fstate_save(task); 34 __fstate_clean(regs); 35 } 36 } 37 38 static inline void fstate_restore(struct task_struct *task, 39 struct pt_regs *regs) 40 { 41 if ((regs->status & SR_FS) != SR_FS_OFF) { 42 __fstate_restore(task); 43 __fstate_clean(regs); 44 } 45 } 46 47 static inline void __switch_to_aux(struct task_struct *prev, 48 struct task_struct *next) 49 { 50 struct pt_regs *regs; 51 52 regs = task_pt_regs(prev); 53 if (unlikely(regs->status & SR_SD)) 54 fstate_save(prev, regs); 55 fstate_restore(next, task_pt_regs(next)); 56 } 57 58 extern bool has_fpu; 59 #else 60 #define has_fpu false 61 #define fstate_save(task, regs) do { } while (0) 62 #define fstate_restore(task, regs) do { } while (0) 63 #define __switch_to_aux(__prev, __next) do { } while (0) 64 #endif 65 66 extern struct task_struct *__switch_to(struct task_struct *, 67 struct task_struct *); 68 69 #define switch_to(prev, next, last) \ 70 do { \ 71 struct task_struct *__prev = (prev); \ 72 struct task_struct *__next = (next); \ 73 if (has_fpu) \ 74 __switch_to_aux(__prev, __next); \ 75 ((last) = __switch_to(__prev, __next)); \ 76 } while (0) 77 78 #endif /* _ASM_RISCV_SWITCH_TO_H */ 79