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 * @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, void *sched_ra, void *sched_cfa); 26 27 /* 28 * For newly created kernel threads switch_to() will return to 29 * ret_from_kernel_thread, newly created user threads to ret_from_fork. 30 * That is, everything following __switch_to() will be skipped for new threads. 31 * So everything that matters to new threads should be placed before __switch_to(). 32 */ 33 #define switch_to(prev, next, last) \ 34 do { \ 35 lose_fpu_inatomic(1, prev); \ 36 lose_lbt_inatomic(1, prev); \ 37 hw_breakpoint_thread_switch(next); \ 38 set_current(next); \ 39 (last) = __switch_to(prev, next, \ 40 __builtin_return_address(0), __builtin_frame_address(0)); \ 41 } while (0) 42 43 #endif /* _ASM_SWITCH_TO_H */ 44