arch/riscv/include/asm/switch_to.h

   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 extern void __fstate_save(struct task_struct *save_to);
  22 extern void __fstate_restore(struct task_struct *restore_from);
  23
  24 static inline void __fstate_clean(struct pt_regs *regs)
  25 {
  26         regs->sstatus |= (regs->sstatus & ~(SR_FS)) | SR_FS_CLEAN;
  27 }
  28
  29 static inline void fstate_save(struct task_struct *task,
  30                                struct pt_regs *regs)
  31 {
  32         if ((regs->sstatus & 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->sstatus & 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->sstatus & SR_SD))
  54                 fstate_save(prev, regs);
  55         fstate_restore(next, task_pt_regs(next));
  56 }
  57
  58 extern struct task_struct *__switch_to(struct task_struct *,
  59                                        struct task_struct *);
  60
  61 #define switch_to(prev, next, last)                     \
  62 do {                                                    \
  63         struct task_struct *__prev = (prev);            \
  64         struct task_struct *__next = (next);            \
  65         __switch_to_aux(__prev, __next);                \
  66         ((last) = __switch_to(__prev, __next));         \
  67 } while (0)
  68
  69 #endif /* _ASM_RISCV_SWITCH_TO_H */