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b920de1b DH |
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> | |
b920de1b DH |
17 | #include <linux/stddef.h> |
18 | #include <linux/unistd.h> | |
19 | #include <linux/ptrace.h> | |
b920de1b | 20 | #include <linux/user.h> |
b920de1b DH |
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> | |
5a0e3ad6 | 27 | #include <linux/slab.h> |
5b0753a9 | 28 | #include <linux/rcupdate.h> |
b920de1b DH |
29 | #include <asm/uaccess.h> |
30 | #include <asm/pgtable.h> | |
b920de1b DH |
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 | * power management idle function, if any.. | |
41 | */ | |
42 | void (*pm_idle)(void); | |
43 | EXPORT_SYMBOL(pm_idle); | |
44 | ||
45 | /* | |
46 | * return saved PC of a blocked thread. | |
47 | */ | |
48 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
49 | { | |
50 | return ((unsigned long *) tsk->thread.sp)[3]; | |
51 | } | |
52 | ||
53 | /* | |
54 | * power off function, if any | |
55 | */ | |
56 | void (*pm_power_off)(void); | |
57 | EXPORT_SYMBOL(pm_power_off); | |
58 | ||
368dd5ac | 59 | #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU) |
b920de1b DH |
60 | /* |
61 | * we use this if we don't have any better idle routine | |
62 | */ | |
63 | static void default_idle(void) | |
64 | { | |
65 | local_irq_disable(); | |
66 | if (!need_resched()) | |
67 | safe_halt(); | |
68 | else | |
69 | local_irq_enable(); | |
70 | } | |
71 | ||
368dd5ac AT |
72 | #else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */ |
73 | /* | |
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. | |
77 | */ | |
78 | static inline void poll_idle(void) | |
79 | { | |
80 | int oldval; | |
81 | ||
82 | local_irq_enable(); | |
83 | ||
84 | /* | |
85 | * Deal with another CPU just having chosen a thread to | |
86 | * run here: | |
87 | */ | |
88 | oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED); | |
89 | ||
90 | if (!oldval) { | |
91 | set_thread_flag(TIF_POLLING_NRFLAG); | |
92 | while (!need_resched()) | |
93 | cpu_relax(); | |
94 | clear_thread_flag(TIF_POLLING_NRFLAG); | |
95 | } else { | |
96 | set_need_resched(); | |
97 | } | |
98 | } | |
99 | #endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */ | |
100 | ||
b920de1b DH |
101 | /* |
102 | * the idle thread | |
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) | |
106 | */ | |
107 | void cpu_idle(void) | |
108 | { | |
b920de1b DH |
109 | /* endless idle loop with no priority at all */ |
110 | for (;;) { | |
5b0753a9 | 111 | rcu_idle_enter(); |
b920de1b DH |
112 | while (!need_resched()) { |
113 | void (*idle)(void); | |
114 | ||
115 | smp_rmb(); | |
116 | idle = pm_idle; | |
368dd5ac AT |
117 | if (!idle) { |
118 | #if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU) | |
119 | idle = poll_idle; | |
120 | #else /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */ | |
b920de1b | 121 | idle = default_idle; |
368dd5ac AT |
122 | #endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */ |
123 | } | |
b920de1b DH |
124 | idle(); |
125 | } | |
5b0753a9 | 126 | rcu_idle_exit(); |
b920de1b | 127 | |
bd2f5536 | 128 | schedule_preempt_disabled(); |
b920de1b DH |
129 | } |
130 | } | |
131 | ||
132 | void release_segments(struct mm_struct *mm) | |
133 | { | |
134 | } | |
135 | ||
136 | void machine_restart(char *cmd) | |
137 | { | |
044264bb | 138 | #ifdef CONFIG_KERNEL_DEBUGGER |
b920de1b DH |
139 | gdbstub_exit(0); |
140 | #endif | |
141 | ||
142 | #ifdef mn10300_unit_hard_reset | |
143 | mn10300_unit_hard_reset(); | |
144 | #else | |
145 | mn10300_proc_hard_reset(); | |
146 | #endif | |
147 | } | |
148 | ||
149 | void machine_halt(void) | |
150 | { | |
044264bb | 151 | #ifdef CONFIG_KERNEL_DEBUGGER |
b920de1b DH |
152 | gdbstub_exit(0); |
153 | #endif | |
154 | } | |
155 | ||
156 | void machine_power_off(void) | |
157 | { | |
044264bb | 158 | #ifdef CONFIG_KERNEL_DEBUGGER |
b920de1b DH |
159 | gdbstub_exit(0); |
160 | #endif | |
161 | } | |
162 | ||
163 | void show_regs(struct pt_regs *regs) | |
164 | { | |
165 | } | |
166 | ||
b920de1b DH |
167 | /* |
168 | * free current thread data structures etc.. | |
169 | */ | |
170 | void exit_thread(void) | |
171 | { | |
172 | exit_fpu(); | |
173 | } | |
174 | ||
175 | void flush_thread(void) | |
176 | { | |
177 | flush_fpu(); | |
178 | } | |
179 | ||
180 | void release_thread(struct task_struct *dead_task) | |
181 | { | |
182 | } | |
183 | ||
184 | /* | |
185 | * we do not have to muck with descriptors here, that is | |
186 | * done in switch_mm() as needed. | |
187 | */ | |
188 | void copy_segments(struct task_struct *p, struct mm_struct *new_mm) | |
189 | { | |
190 | } | |
191 | ||
192 | /* | |
55ccf3fe SS |
193 | * this gets called so that we can store lazy state into memory and copy the |
194 | * current task into the new thread. | |
b920de1b | 195 | */ |
55ccf3fe | 196 | int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) |
b920de1b | 197 | { |
55ccf3fe SS |
198 | unlazy_fpu(src); |
199 | *dst = *src; | |
200 | return 0; | |
b920de1b DH |
201 | } |
202 | ||
203 | /* | |
204 | * set up the kernel stack for a new thread and copy arch-specific thread | |
205 | * control information | |
206 | */ | |
6f2c55b8 | 207 | int copy_thread(unsigned long clone_flags, |
b920de1b | 208 | unsigned long c_usp, unsigned long ustk_size, |
afa86fc4 | 209 | struct task_struct *p) |
b920de1b | 210 | { |
7c7fcf76 | 211 | struct thread_info *ti = task_thread_info(p); |
255461c5 | 212 | struct pt_regs *c_regs; |
b920de1b DH |
213 | unsigned long c_ksp; |
214 | ||
b920de1b DH |
215 | c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE; |
216 | ||
217 | /* allocate the userspace exception frame and set it up */ | |
218 | c_ksp -= sizeof(struct pt_regs); | |
255461c5 | 219 | c_regs = (struct pt_regs *) c_ksp; |
61b7fbc3 | 220 | c_ksp -= 12; /* allocate function call ABI slack */ |
b920de1b | 221 | |
61b7fbc3 | 222 | /* set up things up so the scheduler can start the new task */ |
255461c5 | 223 | p->thread.uregs = c_regs; |
61b7fbc3 AV |
224 | ti->frame = 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; | |
b920de1b | 229 | |
1ea2a016 | 230 | if (unlikely(p->flags & PF_KTHREAD)) { |
61b7fbc3 AV |
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; | |
237 | return 0; | |
238 | } | |
1ea2a016 AV |
239 | *c_regs = *current_pt_regs(); |
240 | if (c_usp) | |
241 | c_regs->sp = c_usp; | |
255461c5 | 242 | c_regs->epsw &= ~EPSW_FE; /* my FPU */ |
b920de1b DH |
243 | |
244 | /* the new TLS pointer is passed in as arg #5 to sys_clone() */ | |
245 | if (clone_flags & CLONE_SETTLS) | |
255461c5 | 246 | c_regs->e2 = current_frame()->d3; |
b920de1b | 247 | |
b920de1b | 248 | p->thread.pc = (unsigned long) ret_from_fork; |
b920de1b DH |
249 | |
250 | return 0; | |
251 | } | |
252 | ||
b920de1b DH |
253 | unsigned long get_wchan(struct task_struct *p) |
254 | { | |
255 | return p->thread.wchan; | |
256 | } |