LXR linux/arch/tile/include/asm/switch

   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
  31struct 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)
  37void _prepare_arch_switch(struct task_struct *next);
  38
  39struct task_struct;
  40#define switch_to(prev, next, last) ((last) = _switch_to((prev), (next)))
  41extern struct task_struct *_switch_to(struct task_struct *prev,
  42                                      struct task_struct *next);
  43
  44/* Helper function for _switch_to(). */
  45extern 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. */
  50extern 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. */
  67void ret_from_fork(void);
  68
  69/* Support function for forking a new kernel thread. */
  70void ret_from_kernel_thread(void *fn, void *arg);
  71
  72/* Called from ret_from_xxx() when a new process starts up. */
  73struct task_struct *sim_notify_fork(struct task_struct *prev);
  74
  75#endif /* !__ASSEMBLY__ */
  76
  77#endif /* _ASM_TILE_SWITCH_TO_H */
  78