1 /* 2 * Copyright (C) 2012 Regents of the University of California 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation, version 2. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 */ 13 14 #ifndef _ASM_RISCV_SWITCH_TO_H 15 #define _ASM_RISCV_SWITCH_TO_H 16 17 #include <asm/processor.h> 18 #include <asm/ptrace.h> 19 #include <asm/csr.h> 20 21 #ifdef CONFIG_FPU 22 extern void __fstate_save(struct task_struct *save_to); 23 extern void __fstate_restore(struct task_struct *restore_from); 24 25 static inline void __fstate_clean(struct pt_regs *regs) 26 { 27 regs->sstatus |= (regs->sstatus & ~(SR_FS)) | SR_FS_CLEAN; 28 } 29 30 static inline void fstate_save(struct task_struct *task, 31 struct pt_regs *regs) 32 { 33 if ((regs->sstatus & 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->sstatus & 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->sstatus & SR_SD)) 55 fstate_save(prev, regs); 56 fstate_restore(next, task_pt_regs(next)); 57 } 58 59 extern bool has_fpu; 60 #else 61 #define has_fpu false 62 #define fstate_save(task, regs) do { } while (0) 63 #define fstate_restore(task, regs) do { } while (0) 64 #define __switch_to_aux(__prev, __next) do { } while (0) 65 #endif 66 67 extern struct task_struct *__switch_to(struct task_struct *, 68 struct task_struct *); 69 70 #define switch_to(prev, next, last) \ 71 do { \ 72 struct task_struct *__prev = (prev); \ 73 struct task_struct *__next = (next); \ 74 if (has_fpu) \ 75 __switch_to_aux(__prev, __next); \ 76 ((last) = __switch_to(__prev, __next)); \ 77 } while (0) 78 79 #endif /* _ASM_RISCV_SWITCH_TO_H */ 80