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 11 struct task_struct; 12 13 /** 14 * __switch_to - switch execution of a task 15 * @prev: The task previously executed. 16 * @next: The task to begin executing. 17 * @next_ti: task_thread_info(next). 18 * @sched_ra: __schedule return address. 19 * @sched_cfa: __schedule call frame address. 20 * 21 * This function is used whilst scheduling to save the context of prev & load 22 * the context of next. Returns prev. 23 */ 24 extern asmlinkage struct task_struct *__switch_to(struct task_struct *prev, 25 struct task_struct *next, struct thread_info *next_ti, 26 void *sched_ra, void *sched_cfa); 27 28 /* 29 * For newly created kernel threads switch_to() will return to 30 * ret_from_kernel_thread, newly created user threads to ret_from_fork. 31 * That is, everything following __switch_to() will be skipped for new threads. 32 * So everything that matters to new threads should be placed before __switch_to(). 33 */ 34 #define switch_to(prev, next, last) \ 35 do { \ 36 lose_fpu_inatomic(1, prev); \ 37 hw_breakpoint_thread_switch(next); \ 38 (last) = __switch_to(prev, next, task_thread_info(next), \ 39 __builtin_return_address(0), __builtin_frame_address(0)); \ 40 } while (0) 41 42 #endif /* _ASM_SWITCH_TO_H */ 43