Linux Kernel  3.7.1
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process.c
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1 /*
2  * linux/arch/h8300/kernel/process.c
3  *
4  * Yoshinori Sato <[email protected]>
5  *
6  * Based on:
7  *
8  * linux/arch/m68knommu/kernel/process.c
9  *
10  * Copyright (C) 1998 D. Jeff Dionne <[email protected]>,
11  * Kenneth Albanowski <[email protected]>,
12  * The Silver Hammer Group, Ltd.
13  *
14  * linux/arch/m68k/kernel/process.c
15  *
16  * Copyright (C) 1995 Hamish Macdonald
17  *
18  * 68060 fixes by Jesper Skov
19  */
20 
21 /*
22  * This file handles the architecture-dependent parts of process handling..
23  */
24 
25 #include <linux/errno.h>
26 #include <linux/module.h>
27 #include <linux/sched.h>
28 #include <linux/kernel.h>
29 #include <linux/mm.h>
30 #include <linux/smp.h>
31 #include <linux/stddef.h>
32 #include <linux/unistd.h>
33 #include <linux/ptrace.h>
34 #include <linux/user.h>
35 #include <linux/interrupt.h>
36 #include <linux/reboot.h>
37 #include <linux/fs.h>
38 #include <linux/slab.h>
39 #include <linux/rcupdate.h>
40 
41 #include <asm/uaccess.h>
42 #include <asm/traps.h>
43 #include <asm/setup.h>
44 #include <asm/pgtable.h>
45 
48 
49 asmlinkage void ret_from_fork(void);
50 
51 /*
52  * The idle loop on an H8/300..
53  */
54 #if !defined(CONFIG_H8300H_SIM) && !defined(CONFIG_H8S_SIM)
55 static void default_idle(void)
56 {
58  if (!need_resched()) {
60  /* XXX: race here! What if need_resched() gets set now? */
61  __asm__("sleep");
62  } else
64 }
65 #else
66 static void default_idle(void)
67 {
68  cpu_relax();
69 }
70 #endif
71 void (*idle)(void) = default_idle;
72 
73 /*
74  * The idle thread. There's no useful work to be
75  * done, so just try to conserve power and have a
76  * low exit latency (ie sit in a loop waiting for
77  * somebody to say that they'd like to reschedule)
78  */
79 void cpu_idle(void)
80 {
81  while (1) {
83  while (!need_resched())
84  idle();
85  rcu_idle_exit();
87  }
88 }
89 
91 {
93  __asm__("jmp @@0");
94 }
95 
96 void machine_halt(void)
97 {
99  __asm__("sleep");
100  for (;;);
101 }
102 
104 {
106  __asm__("sleep");
107  for (;;);
108 }
109 
110 void show_regs(struct pt_regs * regs)
111 {
112  printk("\nPC: %08lx Status: %02x",
113  regs->pc, regs->ccr);
114  printk("\nORIG_ER0: %08lx ER0: %08lx ER1: %08lx",
115  regs->orig_er0, regs->er0, regs->er1);
116  printk("\nER2: %08lx ER3: %08lx ER4: %08lx ER5: %08lx",
117  regs->er2, regs->er3, regs->er4, regs->er5);
118  printk("\nER6' %08lx ",regs->er6);
119  if (user_mode(regs))
120  printk("USP: %08lx\n", rdusp());
121  else
122  printk("\n");
123 }
124 
125 /*
126  * Create a kernel thread
127  */
128 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
129 {
130  long retval;
131  long clone_arg;
133 
134  fs = get_fs();
135  set_fs (KERNEL_DS);
136  clone_arg = flags | CLONE_VM;
137  __asm__("mov.l sp,er3\n\t"
138  "sub.l er2,er2\n\t"
139  "mov.l %2,er1\n\t"
140  "mov.l %1,er0\n\t"
141  "trapa #0\n\t"
142  "cmp.l sp,er3\n\t"
143  "beq 1f\n\t"
144  "mov.l %4,er0\n\t"
145  "mov.l %3,er1\n\t"
146  "jsr @er1\n\t"
147  "mov.l %5,er0\n\t"
148  "trapa #0\n"
149  "1:\n\t"
150  "mov.l er0,%0"
151  :"=r"(retval)
152  :"i"(__NR_clone),"g"(clone_arg),"g"(fn),"g"(arg),"i"(__NR_exit)
153  :"er0","er1","er2","er3");
154  set_fs (fs);
155  return retval;
156 }
157 
158 void flush_thread(void)
159 {
160 }
161 
162 /*
163  * "h8300_fork()".. By the time we get here, the
164  * non-volatile registers have also been saved on the
165  * stack. We do some ugly pointer stuff here.. (see
166  * also copy_thread)
167  */
168 
170 {
171  return -EINVAL;
172 }
173 
175 {
176  return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
177 }
178 
180 {
181  unsigned long clone_flags;
182  unsigned long newsp;
183 
184  /* syscall2 puts clone_flags in er1 and usp in er2 */
185  clone_flags = regs->er1;
186  newsp = regs->er2;
187  if (!newsp)
188  newsp = rdusp();
189  return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
190 
191 }
192 
193 int copy_thread(unsigned long clone_flags,
194  unsigned long usp, unsigned long topstk,
195  struct task_struct * p, struct pt_regs * regs)
196 {
197  struct pt_regs * childregs;
198 
199  childregs = (struct pt_regs *) (THREAD_SIZE + task_stack_page(p)) - 1;
200 
201  *childregs = *regs;
202  childregs->retpc = (unsigned long) ret_from_fork;
203  childregs->er0 = 0;
204 
205  p->thread.usp = usp;
206  p->thread.ksp = (unsigned long)childregs;
207 
208  return 0;
209 }
210 
211 /*
212  * sys_execve() executes a new program.
213  */
214 asmlinkage int sys_execve(const char *name,
215  const char *const *argv,
216  const char *const *envp,
217  int dummy, ...)
218 {
219  int error;
220  struct filename *filename;
221  struct pt_regs *regs = (struct pt_regs *) ((unsigned char *)&dummy-4);
222 
223  filename = getname(name);
224  error = PTR_ERR(filename);
225  if (IS_ERR(filename))
226  return error;
227  error = do_execve(filename->name, argv, envp, regs);
228  putname(filename);
229  return error;
230 }
231 
232 unsigned long thread_saved_pc(struct task_struct *tsk)
233 {
234  return ((struct pt_regs *)tsk->thread.esp0)->pc;
235 }
236 
237 unsigned long get_wchan(struct task_struct *p)
238 {
239  unsigned long fp, pc;
240  unsigned long stack_page;
241  int count = 0;
242  if (!p || p == current || p->state == TASK_RUNNING)
243  return 0;
244 
245  stack_page = (unsigned long)p;
246  fp = ((struct pt_regs *)p->thread.ksp)->er6;
247  do {
248  if (fp < stack_page+sizeof(struct thread_info) ||
249  fp >= 8184+stack_page)
250  return 0;
251  pc = ((unsigned long *)fp)[1];
252  if (!in_sched_functions(pc))
253  return pc;
254  fp = *(unsigned long *) fp;
255  } while (count++ < 16);
256  return 0;
257 }