aboutsummaryrefslogtreecommitdiff
path: root/arch/mn10300/kernel/process.c
blob: 84f4e97e30745ad4d8e9b5d9e032dae5b775542b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
/* MN10300  Process handling code
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/percpu.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
#include <asm/fpu.h>
#include <asm/reset-regs.h>
#include <asm/gdb-stub.h>
#include "internal.h"

/*
 * return saved PC of a blocked thread.
 */
unsigned long thread_saved_pc(struct task_struct *tsk)
{
	return ((unsigned long *) tsk->thread.sp)[3];
}

/*
 * power off function, if any
 */
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);

#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
/*
 * we use this if we don't have any better idle routine
 */
static void default_idle(void)
{
	local_irq_disable();
	if (!need_resched())
		safe_halt();
	else
		local_irq_enable();
}

#else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU  */
/*
 * On SMP it's slightly faster (but much more power-consuming!)
 * to poll the ->work.need_resched flag instead of waiting for the
 * cross-CPU IPI to arrive. Use this option with caution.
 */
static inline void poll_idle(void)
{
	int oldval;

	local_irq_enable();

	/*
	 * Deal with another CPU just having chosen a thread to
	 * run here:
	 */
	oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);

	if (!oldval) {
		set_thread_flag(TIF_POLLING_NRFLAG);
		while (!need_resched())
			cpu_relax();
		clear_thread_flag(TIF_POLLING_NRFLAG);
	} else {
		set_need_resched();
	}
}
#endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */

/*
 * the idle thread
 * - there's no useful work to be done, so just try to conserve power and have
 *   a low exit latency (ie sit in a loop waiting for somebody to say that
 *   they'd like to reschedule)
 */
void cpu_idle(void)
{
	/* endless idle loop with no priority at all */
	for (;;) {
		rcu_idle_enter();
		while (!need_resched()) {
			void (*idle)(void);

			smp_rmb();
			if (!idle) {
#if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
				idle = poll_idle;
#else  /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
				idle = default_idle;
#endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
			}
			idle();
		}
		rcu_idle_exit();

		schedule_preempt_disabled();
	}
}

void release_segments(struct mm_struct *mm)
{
}

void machine_restart(char *cmd)
{
#ifdef CONFIG_KERNEL_DEBUGGER
	gdbstub_exit(0);
#endif

#ifdef mn10300_unit_hard_reset
	mn10300_unit_hard_reset();
#else
	mn10300_proc_hard_reset();
#endif
}

void machine_halt(void)
{
#ifdef CONFIG_KERNEL_DEBUGGER
	gdbstub_exit(0);
#endif
}

void machine_power_off(void)
{
#ifdef CONFIG_KERNEL_DEBUGGER
	gdbstub_exit(0);
#endif
}

void show_regs(struct pt_regs *regs)
{
}

/*
 * free current thread data structures etc..
 */
void exit_thread(void)
{
	exit_fpu();
}

void flush_thread(void)
{
	flush_fpu();
}

void release_thread(struct task_struct *dead_task)
{
}

/*
 * we do not have to muck with descriptors here, that is
 * done in switch_mm() as needed.
 */
void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
{
}

/*
 * this gets called so that we can store lazy state into memory and copy the
 * current task into the new thread.
 */
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
	unlazy_fpu(src);
	*dst = *src;
	return 0;
}

/*
 * set up the kernel stack for a new thread and copy arch-specific thread
 * control information
 */
int copy_thread(unsigned long clone_flags,
		unsigned long c_usp, unsigned long ustk_size,
		struct task_struct *p)
{
	struct thread_info *ti = task_thread_info(p);
	struct pt_regs *c_regs;
	unsigned long c_ksp;

	c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;

	/* allocate the userspace exception frame and set it up */
	c_ksp -= sizeof(struct pt_regs);
	c_regs = (struct pt_regs *) c_ksp;
	c_ksp -= 12; /* allocate function call ABI slack */

	/* set up things up so the scheduler can start the new task */
	p->thread.uregs = c_regs;
	ti->frame	= c_regs;
	p->thread.a3	= (unsigned long) c_regs;
	p->thread.sp	= c_ksp;
	p->thread.wchan	= p->thread.pc;
	p->thread.usp	= c_usp;

	if (unlikely(p->flags & PF_KTHREAD)) {
		memset(c_regs, 0, sizeof(struct pt_regs));
		c_regs->a0 = c_usp; /* function */
		c_regs->d0 = ustk_size; /* argument */
		local_save_flags(c_regs->epsw);
		c_regs->epsw |= EPSW_IE | EPSW_IM_7;
		p->thread.pc	= (unsigned long) ret_from_kernel_thread;
		return 0;
	}
	*c_regs = *current_pt_regs();
	if (c_usp)
		c_regs->sp = c_usp;
	c_regs->epsw &= ~EPSW_FE; /* my FPU */

	/* the new TLS pointer is passed in as arg #5 to sys_clone() */
	if (clone_flags & CLONE_SETTLS)
		c_regs->e2 = current_frame()->d3;

	p->thread.pc	= (unsigned long) ret_from_fork;

	return 0;
}

unsigned long get_wchan(struct task_struct *p)
{
	return p->thread.wchan;
}