Linux Kernel  3.7.1
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process.c
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1 /*
2  * linux/arch/m32r/kernel/process.c
3  *
4  * Copyright (c) 2001, 2002 Hiroyuki Kondo, Hirokazu Takata,
5  * Hitoshi Yamamoto
6  * Taken from sh version.
7  * Copyright (C) 1995 Linus Torvalds
8  * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
9  */
10 
11 #undef DEBUG_PROCESS
12 #ifdef DEBUG_PROCESS
13 #define DPRINTK(fmt, args...) printk("%s:%d:%s: " fmt, __FILE__, __LINE__, \
14  __func__, ##args)
15 #else
16 #define DPRINTK(fmt, args...)
17 #endif
18 
19 /*
20  * This file handles the architecture-dependent parts of process handling..
21  */
22 
23 #include <linux/fs.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/ptrace.h>
27 #include <linux/unistd.h>
28 #include <linux/hardirq.h>
29 #include <linux/rcupdate.h>
30 
31 #include <asm/io.h>
32 #include <asm/uaccess.h>
33 #include <asm/mmu_context.h>
34 #include <asm/elf.h>
35 #include <asm/m32r.h>
36 
37 #include <linux/err.h>
38 
39 /*
40  * Return saved PC of a blocked thread.
41  */
42 unsigned long thread_saved_pc(struct task_struct *tsk)
43 {
44  return tsk->thread.lr;
45 }
46 
47 /*
48  * Powermanagement idle function, if any..
49  */
50 static void (*pm_idle)(void) = NULL;
51 
54 
55 /*
56  * We use this is we don't have any better
57  * idle routine..
58  */
59 static void default_idle(void)
60 {
61  /* M32R_FIXME: Please use "cpu_sleep" mode. */
62  cpu_relax();
63 }
64 
65 /*
66  * On SMP it's slightly faster (but much more power-consuming!)
67  * to poll the ->work.need_resched flag instead of waiting for the
68  * cross-CPU IPI to arrive. Use this option with caution.
69  */
70 static void poll_idle (void)
71 {
72  /* M32R_FIXME */
73  cpu_relax();
74 }
75 
76 /*
77  * The idle thread. There's no useful work to be
78  * done, so just try to conserve power and have a
79  * low exit latency (ie sit in a loop waiting for
80  * somebody to say that they'd like to reschedule)
81  */
82 void cpu_idle (void)
83 {
84  /* endless idle loop with no priority at all */
85  while (1) {
87  while (!need_resched()) {
88  void (*idle)(void) = pm_idle;
89 
90  if (!idle)
92 
93  idle();
94  }
95  rcu_idle_exit();
97  }
98 }
99 
101 {
102 #if defined(CONFIG_PLAT_MAPPI3)
103  outw(1, (unsigned long)PLD_REBOOT);
104 #endif
105 
106  printk("Please push reset button!\n");
107  while (1)
108  cpu_relax();
109 }
110 
111 void machine_halt(void)
112 {
113  printk("Please push reset button!\n");
114  while (1)
115  cpu_relax();
116 }
117 
119 {
120  /* M32R_FIXME */
121 }
122 
123 static int __init idle_setup (char *str)
124 {
125  if (!strncmp(str, "poll", 4)) {
126  printk("using poll in idle threads.\n");
127  pm_idle = poll_idle;
128  } else if (!strncmp(str, "sleep", 4)) {
129  printk("using sleep in idle threads.\n");
131  }
132 
133  return 1;
134 }
135 
136 __setup("idle=", idle_setup);
137 
138 void show_regs(struct pt_regs * regs)
139 {
140  printk("\n");
141  printk("BPC[%08lx]:PSW[%08lx]:LR [%08lx]:FP [%08lx]\n", \
142  regs->bpc, regs->psw, regs->lr, regs->fp);
143  printk("BBPC[%08lx]:BBPSW[%08lx]:SPU[%08lx]:SPI[%08lx]\n", \
144  regs->bbpc, regs->bbpsw, regs->spu, regs->spi);
145  printk("R0 [%08lx]:R1 [%08lx]:R2 [%08lx]:R3 [%08lx]\n", \
146  regs->r0, regs->r1, regs->r2, regs->r3);
147  printk("R4 [%08lx]:R5 [%08lx]:R6 [%08lx]:R7 [%08lx]\n", \
148  regs->r4, regs->r5, regs->r6, regs->r7);
149  printk("R8 [%08lx]:R9 [%08lx]:R10[%08lx]:R11[%08lx]\n", \
150  regs->r8, regs->r9, regs->r10, regs->r11);
151  printk("R12[%08lx]\n", \
152  regs->r12);
153 
154 #if defined(CONFIG_ISA_M32R2) && defined(CONFIG_ISA_DSP_LEVEL2)
155  printk("ACC0H[%08lx]:ACC0L[%08lx]\n", \
156  regs->acc0h, regs->acc0l);
157  printk("ACC1H[%08lx]:ACC1L[%08lx]\n", \
158  regs->acc1h, regs->acc1l);
159 #elif defined(CONFIG_ISA_M32R2) || defined(CONFIG_ISA_M32R)
160  printk("ACCH[%08lx]:ACCL[%08lx]\n", \
161  regs->acc0h, regs->acc0l);
162 #else
163 #error unknown isa configuration
164 #endif
165 }
166 
167 /*
168  * Create a kernel thread
169  */
170 
171 /*
172  * This is the mechanism for creating a new kernel thread.
173  *
174  * NOTE! Only a kernel-only process(ie the swapper or direct descendants
175  * who haven't done an "execve()") should use this: it will work within
176  * a system call from a "real" process, but the process memory space will
177  * not be free'd until both the parent and the child have exited.
178  */
179 static void kernel_thread_helper(void *nouse, int (*fn)(void *), void *arg)
180 {
181  fn(arg);
182  do_exit(-1);
183 }
184 
185 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
186 {
187  struct pt_regs regs;
188 
189  memset(&regs, 0, sizeof (regs));
190  regs.r1 = (unsigned long)fn;
191  regs.r2 = (unsigned long)arg;
192 
193  regs.bpc = (unsigned long)kernel_thread_helper;
194 
195  regs.psw = M32R_PSW_BIE;
196 
197  /* Ok, create the new process. */
198  return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
199  NULL);
200 }
201 
202 /*
203  * Free current thread data structures etc..
204  */
205 void exit_thread(void)
206 {
207  /* Nothing to do. */
208  DPRINTK("pid = %d\n", current->pid);
209 }
210 
211 void flush_thread(void)
212 {
213  DPRINTK("pid = %d\n", current->pid);
214  memset(&current->thread.debug_trap, 0, sizeof(struct debug_trap));
215 }
216 
217 void release_thread(struct task_struct *dead_task)
218 {
219  /* do nothing */
220  DPRINTK("pid = %d\n", dead_task->pid);
221 }
222 
223 /* Fill in the fpu structure for a core dump.. */
225 {
226  return 0; /* Task didn't use the fpu at all. */
227 }
228 
229 int copy_thread(unsigned long clone_flags, unsigned long spu,
230  unsigned long unused, struct task_struct *tsk, struct pt_regs *regs)
231 {
232  struct pt_regs *childregs = task_pt_regs(tsk);
233  extern void ret_from_fork(void);
234 
235  /* Copy registers */
236  *childregs = *regs;
237 
238  childregs->spu = spu;
239  childregs->r0 = 0; /* Child gets zero as return value */
240  regs->r0 = tsk->pid;
241  tsk->thread.sp = (unsigned long)childregs;
242  tsk->thread.lr = (unsigned long)ret_from_fork;
243 
244  return 0;
245 }
246 
247 asmlinkage int sys_fork(unsigned long r0, unsigned long r1, unsigned long r2,
248  unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6,
249  struct pt_regs regs)
250 {
251 #ifdef CONFIG_MMU
252  return do_fork(SIGCHLD, regs.spu, &regs, 0, NULL, NULL);
253 #else
254  return -EINVAL;
255 #endif /* CONFIG_MMU */
256 }
257 
258 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
259  unsigned long parent_tidptr,
260  unsigned long child_tidptr,
261  unsigned long r4, unsigned long r5, unsigned long r6,
262  struct pt_regs regs)
263 {
264  if (!newsp)
265  newsp = regs.spu;
266 
267  return do_fork(clone_flags, newsp, &regs, 0,
268  (int __user *)parent_tidptr, (int __user *)child_tidptr);
269 }
270 
271 /*
272  * This is trivial, and on the face of it looks like it
273  * could equally well be done in user mode.
274  *
275  * Not so, for quite unobvious reasons - register pressure.
276  * In user mode vfork() cannot have a stack frame, and if
277  * done by calling the "clone()" system call directly, you
278  * do not have enough call-clobbered registers to hold all
279  * the information you need.
280  */
281 asmlinkage int sys_vfork(unsigned long r0, unsigned long r1, unsigned long r2,
282  unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6,
283  struct pt_regs regs)
284 {
285  return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.spu, &regs, 0,
286  NULL, NULL);
287 }
288 
289 /*
290  * sys_execve() executes a new program.
291  */
292 asmlinkage int sys_execve(const char __user *ufilename,
293  const char __user *const __user *uargv,
294  const char __user *const __user *uenvp,
295  unsigned long r3, unsigned long r4, unsigned long r5,
296  unsigned long r6, struct pt_regs regs)
297 {
298  int error;
299  struct filename *filename;
300 
301  filename = getname(ufilename);
302  error = PTR_ERR(filename);
303  if (IS_ERR(filename))
304  goto out;
305 
306  error = do_execve(filename->name, uargv, uenvp, &regs);
307  putname(filename);
308 out:
309  return error;
310 }
311 
312 /*
313  * These bracket the sleeping functions..
314  */
315 #define first_sched ((unsigned long) scheduling_functions_start_here)
316 #define last_sched ((unsigned long) scheduling_functions_end_here)
317 
318 unsigned long get_wchan(struct task_struct *p)
319 {
320  /* M32R_FIXME */
321  return (0);
322 }