1/* MN10300  Process handling code
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
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.
10 */
11#include <linux/module.h>
12#include <linux/errno.h>
13#include <linux/sched.h>
14#include <linux/kernel.h>
15#include <linux/mm.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>
26#include <linux/fs.h>
27#include <linux/slab.h>
28#include <linux/rcupdate.h>
29#include <asm/uaccess.h>
30#include <asm/pgtable.h>
31#include <asm/io.h>
32#include <asm/processor.h>
33#include <asm/mmu_context.h>
34#include <asm/fpu.h>
35#include <asm/reset-regs.h>
36#include <asm/gdb-stub.h>
37#include "internal.h"
38
39/*
40 * return saved PC of a blocked thread.
41 */
42unsigned long thread_saved_pc(struct task_struct *tsk)
43{
44	return ((unsigned long *) tsk->thread.sp)[3];
45}
46
47/*
48 * power off function, if any
49 */
50void (*pm_power_off)(void);
51EXPORT_SYMBOL(pm_power_off);
52
53/*
54 * On SMP it's slightly faster (but much more power-consuming!)
55 * to poll the ->work.need_resched flag instead of waiting for the
56 * cross-CPU IPI to arrive. Use this option with caution.
57 *
58 * tglx: No idea why this depends on HOTPLUG_CPU !?!
59 */
60#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
61void arch_cpu_idle(void)
62{
63	safe_halt();
64}
65#endif
66
67void release_segments(struct mm_struct *mm)
68{
69}
70
71void machine_restart(char *cmd)
72{
73#ifdef CONFIG_KERNEL_DEBUGGER
74	gdbstub_exit(0);
75#endif
76
77#ifdef mn10300_unit_hard_reset
78	mn10300_unit_hard_reset();
79#else
80	mn10300_proc_hard_reset();
81#endif
82}
83
84void machine_halt(void)
85{
86#ifdef CONFIG_KERNEL_DEBUGGER
87	gdbstub_exit(0);
88#endif
89}
90
91void machine_power_off(void)
92{
93#ifdef CONFIG_KERNEL_DEBUGGER
94	gdbstub_exit(0);
95#endif
96}
97
98void show_regs(struct pt_regs *regs)
99{
100	show_regs_print_info(KERN_DEFAULT);
101}
102
103/*
104 * free current thread data structures etc..
105 */
106void exit_thread(void)
107{
108	exit_fpu();
109}
110
111void flush_thread(void)
112{
113	flush_fpu();
114}
115
116void release_thread(struct task_struct *dead_task)
117{
118}
119
120/*
121 * we do not have to muck with descriptors here, that is
122 * done in switch_mm() as needed.
123 */
124void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
125{
126}
127
128/*
129 * this gets called so that we can store lazy state into memory and copy the
130 * current task into the new thread.
131 */
132int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
133{
134	unlazy_fpu(src);
135	*dst = *src;
136	return 0;
137}
138
139/*
140 * set up the kernel stack for a new thread and copy arch-specific thread
141 * control information
142 */
143int copy_thread(unsigned long clone_flags,
144		unsigned long c_usp, unsigned long ustk_size,
145		struct task_struct *p)
146{
147	struct thread_info *ti = task_thread_info(p);
148	struct pt_regs *c_regs;
149	unsigned long c_ksp;
150
151	c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
152
153	/* allocate the userspace exception frame and set it up */
154	c_ksp -= sizeof(struct pt_regs);
155	c_regs = (struct pt_regs *) c_ksp;
156	c_ksp -= 12; /* allocate function call ABI slack */
157
158	/* set up things up so the scheduler can start the new task */
159	p->thread.uregs = c_regs;
160	ti->frame	= c_regs;
161	p->thread.a3	= (unsigned long) c_regs;
162	p->thread.sp	= c_ksp;
163	p->thread.wchan	= p->thread.pc;
164	p->thread.usp	= c_usp;
165
166	if (unlikely(p->flags & PF_KTHREAD)) {
167		memset(c_regs, 0, sizeof(struct pt_regs));
168		c_regs->a0 = c_usp; /* function */
169		c_regs->d0 = ustk_size; /* argument */
170		local_save_flags(c_regs->epsw);
171		c_regs->epsw |= EPSW_IE | EPSW_IM_7;
172		p->thread.pc	= (unsigned long) ret_from_kernel_thread;
173		return 0;
174	}
175	*c_regs = *current_pt_regs();
176	if (c_usp)
177		c_regs->sp = c_usp;
178	c_regs->epsw &= ~EPSW_FE; /* my FPU */
179
180	/* the new TLS pointer is passed in as arg #5 to sys_clone() */
181	if (clone_flags & CLONE_SETTLS)
182		c_regs->e2 = current_frame()->d3;
183
184	p->thread.pc	= (unsigned long) ret_from_fork;
185
186	return 0;
187}
188
189unsigned long get_wchan(struct task_struct *p)
190{
191	return p->thread.wchan;
192}
193