1 /* MN10300 Process handling code
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/sched.h>
14 #include <linux/kernel.h>
16 #include <linux/smp.h>
17 #include <linux/stddef.h>
18 #include <linux/unistd.h>
19 #include <linux/ptrace.h>
20 #include <linux/user.h>
21 #include <linux/interrupt.h>
22 #include <linux/delay.h>
23 #include <linux/reboot.h>
24 #include <linux/percpu.h>
25 #include <linux/err.h>
27 #include <linux/slab.h>
28 #include <linux/rcupdate.h>
29 #include <asm/uaccess.h>
30 #include <asm/pgtable.h>
32 #include <asm/processor.h>
33 #include <asm/mmu_context.h>
35 #include <asm/reset-regs.h>
36 #include <asm/gdb-stub.h>
40 * power management idle function, if any..
42 void (*pm_idle)(void);
43 EXPORT_SYMBOL(pm_idle);
46 * return saved PC of a blocked thread.
48 unsigned long thread_saved_pc(struct task_struct *tsk)
50 return ((unsigned long *) tsk->thread.sp)[3];
54 * power off function, if any
56 void (*pm_power_off)(void);
57 EXPORT_SYMBOL(pm_power_off);
59 #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
61 * we use this if we don't have any better idle routine
63 static void default_idle(void)
72 #else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
74 * On SMP it's slightly faster (but much more power-consuming!)
75 * to poll the ->work.need_resched flag instead of waiting for the
76 * cross-CPU IPI to arrive. Use this option with caution.
78 static inline void poll_idle(void)
85 * Deal with another CPU just having chosen a thread to
88 oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
91 set_thread_flag(TIF_POLLING_NRFLAG);
92 while (!need_resched())
94 clear_thread_flag(TIF_POLLING_NRFLAG);
99 #endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
103 * - there's no useful work to be done, so just try to conserve power and have
104 * a low exit latency (ie sit in a loop waiting for somebody to say that
105 * they'd like to reschedule)
109 /* endless idle loop with no priority at all */
112 while (!need_resched()) {
118 #if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
120 #else /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
122 #endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
128 schedule_preempt_disabled();
132 void release_segments(struct mm_struct *mm)
136 void machine_restart(char *cmd)
138 #ifdef CONFIG_KERNEL_DEBUGGER
142 #ifdef mn10300_unit_hard_reset
143 mn10300_unit_hard_reset();
145 mn10300_proc_hard_reset();
149 void machine_halt(void)
151 #ifdef CONFIG_KERNEL_DEBUGGER
156 void machine_power_off(void)
158 #ifdef CONFIG_KERNEL_DEBUGGER
163 void show_regs(struct pt_regs *regs)
168 * free current thread data structures etc..
170 void exit_thread(void)
175 void flush_thread(void)
180 void release_thread(struct task_struct *dead_task)
185 * we do not have to muck with descriptors here, that is
186 * done in switch_mm() as needed.
188 void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
193 * this gets called so that we can store lazy state into memory and copy the
194 * current task into the new thread.
196 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
204 * set up the kernel stack for a new thread and copy arch-specific thread
205 * control information
207 int copy_thread(unsigned long clone_flags,
208 unsigned long c_usp, unsigned long ustk_size,
209 struct task_struct *p)
211 struct thread_info *ti = task_thread_info(p);
212 struct pt_regs *c_regs;
215 c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
217 /* allocate the userspace exception frame and set it up */
218 c_ksp -= sizeof(struct pt_regs);
219 c_regs = (struct pt_regs *) c_ksp;
220 c_ksp -= 12; /* allocate function call ABI slack */
222 /* set up things up so the scheduler can start the new task */
223 p->thread.uregs = c_regs;
225 p->thread.a3 = (unsigned long) c_regs;
226 p->thread.sp = c_ksp;
227 p->thread.wchan = p->thread.pc;
228 p->thread.usp = c_usp;
230 if (unlikely(p->flags & PF_KTHREAD)) {
231 memset(c_regs, 0, sizeof(struct pt_regs));
232 c_regs->a0 = c_usp; /* function */
233 c_regs->d0 = ustk_size; /* argument */
234 local_save_flags(c_regs->epsw);
235 c_regs->epsw |= EPSW_IE | EPSW_IM_7;
236 p->thread.pc = (unsigned long) ret_from_kernel_thread;
239 *c_regs = *current_pt_regs();
242 c_regs->epsw &= ~EPSW_FE; /* my FPU */
244 /* the new TLS pointer is passed in as arg #5 to sys_clone() */
245 if (clone_flags & CLONE_SETTLS)
246 c_regs->e2 = current_frame()->d3;
248 p->thread.pc = (unsigned long) ret_from_fork;
253 unsigned long get_wchan(struct task_struct *p)
255 return p->thread.wchan;