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/sched/debug.h>
15 #include <linux/sched/task.h>
16 #include <linux/sched/task_stack.h>
17 #include <linux/kernel.h>
18 #include <linux/mm.h>
19 #include <linux/smp.h>
20 #include <linux/stddef.h>
21 #include <linux/unistd.h>
22 #include <linux/ptrace.h>
23 #include <linux/user.h>
24 #include <linux/interrupt.h>
25 #include <linux/delay.h>
26 #include <linux/reboot.h>
27 #include <linux/percpu.h>
28 #include <linux/err.h>
29 #include <linux/fs.h>
30 #include <linux/slab.h>
31 #include <linux/rcupdate.h>
32 #include <linux/uaccess.h>
33 #include <asm/pgtable.h>
34 #include <asm/io.h>
35 #include <asm/processor.h>
36 #include <asm/mmu_context.h>
37 #include <asm/fpu.h>
38 #include <asm/reset-regs.h>
39 #include <asm/gdb-stub.h>
40 #include "internal.h"
41
42 /*
43 * power off function, if any
44 */
45 void (*pm_power_off)(void);
46 EXPORT_SYMBOL(pm_power_off);
47
48 /*
49 * On SMP it's slightly faster (but much more power-consuming!)
50 * to poll the ->work.need_resched flag instead of waiting for the
51 * cross-CPU IPI to arrive. Use this option with caution.
52 *
53 * tglx: No idea why this depends on HOTPLUG_CPU !?!
54 */
55 #if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
arch_cpu_idle(void)56 void arch_cpu_idle(void)
57 {
58 safe_halt();
59 }
60 #endif
61
machine_restart(char * cmd)62 void machine_restart(char *cmd)
63 {
64 #ifdef CONFIG_KERNEL_DEBUGGER
65 gdbstub_exit(0);
66 #endif
67
68 #ifdef mn10300_unit_hard_reset
69 mn10300_unit_hard_reset();
70 #else
71 mn10300_proc_hard_reset();
72 #endif
73 }
74
machine_halt(void)75 void machine_halt(void)
76 {
77 #ifdef CONFIG_KERNEL_DEBUGGER
78 gdbstub_exit(0);
79 #endif
80 }
81
machine_power_off(void)82 void machine_power_off(void)
83 {
84 #ifdef CONFIG_KERNEL_DEBUGGER
85 gdbstub_exit(0);
86 #endif
87 }
88
show_regs(struct pt_regs * regs)89 void show_regs(struct pt_regs *regs)
90 {
91 show_regs_print_info(KERN_DEFAULT);
92 }
93
94 /*
95 * free current thread data structures etc..
96 */
exit_thread(struct task_struct * tsk)97 void exit_thread(struct task_struct *tsk)
98 {
99 exit_fpu(tsk);
100 }
101
flush_thread(void)102 void flush_thread(void)
103 {
104 flush_fpu();
105 }
106
release_thread(struct task_struct * dead_task)107 void release_thread(struct task_struct *dead_task)
108 {
109 }
110
111 /*
112 * this gets called so that we can store lazy state into memory and copy the
113 * current task into the new thread.
114 */
arch_dup_task_struct(struct task_struct * dst,struct task_struct * src)115 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
116 {
117 unlazy_fpu(src);
118 *dst = *src;
119 return 0;
120 }
121
122 /*
123 * set up the kernel stack for a new thread and copy arch-specific thread
124 * control information
125 */
copy_thread(unsigned long clone_flags,unsigned long c_usp,unsigned long ustk_size,struct task_struct * p)126 int copy_thread(unsigned long clone_flags,
127 unsigned long c_usp, unsigned long ustk_size,
128 struct task_struct *p)
129 {
130 struct thread_info *ti = task_thread_info(p);
131 struct pt_regs *c_regs;
132 unsigned long c_ksp;
133
134 c_ksp = (unsigned long) task_stack_page(p) + THREAD_SIZE;
135
136 /* allocate the userspace exception frame and set it up */
137 c_ksp -= sizeof(struct pt_regs);
138 c_regs = (struct pt_regs *) c_ksp;
139 c_ksp -= 12; /* allocate function call ABI slack */
140
141 /* set up things up so the scheduler can start the new task */
142 p->thread.uregs = c_regs;
143 ti->frame = c_regs;
144 p->thread.a3 = (unsigned long) c_regs;
145 p->thread.sp = c_ksp;
146 p->thread.wchan = p->thread.pc;
147 p->thread.usp = c_usp;
148
149 if (unlikely(p->flags & PF_KTHREAD)) {
150 memset(c_regs, 0, sizeof(struct pt_regs));
151 c_regs->a0 = c_usp; /* function */
152 c_regs->d0 = ustk_size; /* argument */
153 local_save_flags(c_regs->epsw);
154 c_regs->epsw |= EPSW_IE | EPSW_IM_7;
155 p->thread.pc = (unsigned long) ret_from_kernel_thread;
156 return 0;
157 }
158 *c_regs = *current_pt_regs();
159 if (c_usp)
160 c_regs->sp = c_usp;
161 c_regs->epsw &= ~EPSW_FE; /* my FPU */
162
163 /* the new TLS pointer is passed in as arg #5 to sys_clone() */
164 if (clone_flags & CLONE_SETTLS)
165 c_regs->e2 = current_frame()->d3;
166
167 p->thread.pc = (unsigned long) ret_from_fork;
168
169 return 0;
170 }
171
get_wchan(struct task_struct * p)172 unsigned long get_wchan(struct task_struct *p)
173 {
174 return p->thread.wchan;
175 }
176