1 /* 2 * Copyright 2010 Tilera Corporation. All Rights Reserved. 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, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 11 * NON INFRINGEMENT. See the GNU General Public License for 12 * more details. 13 */ 14 15 #ifndef _ASM_TILE_SWITCH_TO_H 16 #define _ASM_TILE_SWITCH_TO_H 17 18 #include <arch/sim_def.h> 19 20 /* 21 * switch_to(n) should switch tasks to task nr n, first 22 * checking that n isn't the current task, in which case it does nothing. 23 * The number of callee-saved registers saved on the kernel stack 24 * is defined here for use in copy_thread() and must agree with __switch_to(). 25 */ 26 #define CALLEE_SAVED_FIRST_REG 30 27 #define CALLEE_SAVED_REGS_COUNT 24 /* r30 to r52, plus an empty to align */ 28 29 #ifndef __ASSEMBLY__ 30 31 struct task_struct; 32 33 /* 34 * Pause the DMA engine and static network before task switching. 35 */ 36 #define prepare_arch_switch(next) _prepare_arch_switch(next) 37 void _prepare_arch_switch(struct task_struct *next); 38 39 struct task_struct; 40 #define switch_to(prev, next, last) ((last) = _switch_to((prev), (next))) 41 extern struct task_struct *_switch_to(struct task_struct *prev, 42 struct task_struct *next); 43 44 /* Helper function for _switch_to(). */ 45 extern struct task_struct *__switch_to(struct task_struct *prev, 46 struct task_struct *next, 47 unsigned long new_system_save_k_0); 48 49 /* Address that switched-away from tasks are at. */ 50 extern unsigned long get_switch_to_pc(void); 51 52 /* 53 * Kernel threads can check to see if they need to migrate their 54 * stack whenever they return from a context switch; for user 55 * threads, we defer until they are returning to user-space. 56 * We defer homecache migration until the runqueue lock is released. 57 */ 58 #define finish_arch_post_lock_switch() do { \ 59 __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_SWITCH | \ 60 (current->pid << _SIM_CONTROL_OPERATOR_BITS)); \ 61 if (current->mm == NULL && !kstack_hash && \ 62 current_thread_info()->homecache_cpu != raw_smp_processor_id()) \ 63 homecache_migrate_kthread(); \ 64 } while (0) 65 66 /* Support function for forking a new task. */ 67 void ret_from_fork(void); 68 69 /* Support function for forking a new kernel thread. */ 70 void ret_from_kernel_thread(void *fn, void *arg); 71 72 /* Called from ret_from_xxx() when a new process starts up. */ 73 struct task_struct *sim_notify_fork(struct task_struct *prev); 74 75 #endif /* !__ASSEMBLY__ */ 76 77 #endif /* _ASM_TILE_SWITCH_TO_H */ 78