LXR linux/arch/riscv/include/asm/switch

   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
  15extern void __fstate_save(struct task_struct *save_to);
  16extern void __fstate_restore(struct task_struct *restore_from);
  17
  18static inline void __fstate_clean(struct pt_regs *regs)
  19{
  20        regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN;
  21}
  22
  23static 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
  29static 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
  38static 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
  47static 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
  58extern 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
  66extern struct task_struct *__switch_to(struct task_struct *,
  67                                       struct task_struct *);
  68
  69#define switch_to(prev, next, last)                     \
  70do {                                                    \
  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