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/hwcap.h> 12 #include <asm/processor.h> 13 #include <asm/ptrace.h> 14 #include <asm/csr.h> 15 16 #ifdef CONFIG_FPU 17 extern void __fstate_save(struct task_struct *save_to); 18 extern void __fstate_restore(struct task_struct *restore_from); 19 20 static inline void __fstate_clean(struct pt_regs *regs) 21 { 22 regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN; 23 } 24 25 static inline void fstate_off(struct task_struct *task, 26 struct pt_regs *regs) 27 { 28 regs->status = (regs->status & ~SR_FS) | SR_FS_OFF; 29 } 30 31 static inline void fstate_save(struct task_struct *task, 32 struct pt_regs *regs) 33 { 34 if ((regs->status & SR_FS) == SR_FS_DIRTY) { 35 __fstate_save(task); 36 __fstate_clean(regs); 37 } 38 } 39 40 static inline void fstate_restore(struct task_struct *task, 41 struct pt_regs *regs) 42 { 43 if ((regs->status & SR_FS) != SR_FS_OFF) { 44 __fstate_restore(task); 45 __fstate_clean(regs); 46 } 47 } 48 49 static inline void __switch_to_aux(struct task_struct *prev, 50 struct task_struct *next) 51 { 52 struct pt_regs *regs; 53 54 regs = task_pt_regs(prev); 55 if (unlikely(regs->status & SR_SD)) 56 fstate_save(prev, regs); 57 fstate_restore(next, task_pt_regs(next)); 58 } 59 60 static __always_inline bool has_fpu(void) 61 { 62 return riscv_has_extension_likely(RISCV_ISA_EXT_f) || 63 riscv_has_extension_likely(RISCV_ISA_EXT_d); 64 } 65 #else 66 static __always_inline bool has_fpu(void) { return false; } 67 #define fstate_save(task, regs) do { } while (0) 68 #define fstate_restore(task, regs) do { } while (0) 69 #define __switch_to_aux(__prev, __next) do { } while (0) 70 #endif 71 72 extern struct task_struct *__switch_to(struct task_struct *, 73 struct task_struct *); 74 75 #define switch_to(prev, next, last) \ 76 do { \ 77 struct task_struct *__prev = (prev); \ 78 struct task_struct *__next = (next); \ 79 if (has_fpu()) \ 80 __switch_to_aux(__prev, __next); \ 81 ((last) = __switch_to(__prev, __next)); \ 82 } while (0) 83 84 #endif /* _ASM_RISCV_SWITCH_TO_H */ 85