arch/loongarch/include/asm/switch_to.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
   4  */
   5 #ifndef _ASM_SWITCH_TO_H
   6 #define _ASM_SWITCH_TO_H
   7
   8 #include <asm/cpu-features.h>
   9 #include <asm/fpu.h>
  10 #include <asm/lbt.h>
  11
  12 struct task_struct;
  13
  14 /**
  15  * __switch_to - switch execution of a task
  16  * @prev:       The task previously executed.
  17  * @next:       The task to begin executing.
  18  * @next_ti:    task_thread_info(next).
  19  * @sched_ra:   __schedule return address.
  20  * @sched_cfa:  __schedule call frame address.
  21  *
  22  * This function is used whilst scheduling to save the context of prev & load
  23  * the context of next. Returns prev.
  24  */
  25 extern asmlinkage struct task_struct *__switch_to(struct task_struct *prev,
  26                         struct task_struct *next, struct thread_info *next_ti,
  27                         void *sched_ra, void *sched_cfa);
  28
  29 /*
  30  * For newly created kernel threads switch_to() will return to
  31  * ret_from_kernel_thread, newly created user threads to ret_from_fork.
  32  * That is, everything following __switch_to() will be skipped for new threads.
  33  * So everything that matters to new threads should be placed before __switch_to().
  34  */
  35 #define switch_to(prev, next, last)                                             \
  36 do {                                                                            \
  37         lose_fpu_inatomic(1, prev);                                             \
  38         lose_lbt_inatomic(1, prev);                                             \
  39         hw_breakpoint_thread_switch(next);                                      \
  40         (last) = __switch_to(prev, next, task_thread_info(next),                \
  41                  __builtin_return_address(0), __builtin_frame_address(0));      \
  42 } while (0)
  43
  44 #endif /* _ASM_SWITCH_TO_H */