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/arch/cris/arch-v10/kernel/process.c

https://bitbucket.org/evzijst/gittest
C | 270 lines | 147 code | 46 blank | 77 comment | 16 complexity | bac57efcf542ea693d03624d562d96cf MD5 | raw file
  1/* $Id: process.c,v 1.9 2004/10/19 13:07:37 starvik Exp $
  2 * 
  3 *  linux/arch/cris/kernel/process.c
  4 *
  5 *  Copyright (C) 1995  Linus Torvalds
  6 *  Copyright (C) 2000-2002  Axis Communications AB
  7 *
  8 *  Authors:   Bjorn Wesen (bjornw@axis.com)
  9 *             Mikael Starvik (starvik@axis.com)
 10 *
 11 * This file handles the architecture-dependent parts of process handling..
 12 */
 13
 14#include <linux/config.h>
 15#include <linux/sched.h>
 16#include <linux/err.h>
 17#include <linux/fs.h>
 18#include <linux/slab.h>
 19#include <asm/arch/svinto.h>
 20#include <linux/init.h>
 21
 22#ifdef CONFIG_ETRAX_GPIO
 23void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
 24#endif
 25
 26/*
 27 * We use this if we don't have any better
 28 * idle routine..
 29 */
 30void default_idle(void)
 31{
 32#ifdef CONFIG_ETRAX_GPIO
 33  etrax_gpio_wake_up_check();
 34#endif
 35}
 36
 37/*
 38 * Free current thread data structures etc..
 39 */
 40
 41void exit_thread(void)
 42{
 43	/* Nothing needs to be done.  */
 44}
 45
 46/* if the watchdog is enabled, we can simply disable interrupts and go
 47 * into an eternal loop, and the watchdog will reset the CPU after 0.1s
 48 * if on the other hand the watchdog wasn't enabled, we just enable it and wait
 49 */
 50
 51void hard_reset_now (void)
 52{
 53	/*
 54	 * Don't declare this variable elsewhere.  We don't want any other
 55	 * code to know about it than the watchdog handler in entry.S and
 56	 * this code, implementing hard reset through the watchdog.
 57	 */
 58#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
 59	extern int cause_of_death;
 60#endif
 61
 62	printk("*** HARD RESET ***\n");
 63	local_irq_disable();
 64
 65#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
 66	cause_of_death = 0xbedead;
 67#else
 68	/* Since we dont plan to keep on reseting the watchdog,
 69	   the key can be arbitrary hence three */
 70	*R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
 71		IO_STATE(R_WATCHDOG, enable, start);
 72#endif
 73
 74	while(1) /* waiting for RETRIBUTION! */ ;
 75}
 76
 77/*
 78 * Return saved PC of a blocked thread.
 79 */
 80unsigned long thread_saved_pc(struct task_struct *t)
 81{
 82	return (unsigned long)user_regs(t->thread_info)->irp;
 83}
 84
 85static void kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
 86{
 87  fn(arg);
 88  do_exit(-1); /* Should never be called, return bad exit value */
 89}
 90
 91/*
 92 * Create a kernel thread
 93 */
 94int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 95{
 96	struct pt_regs regs;
 97
 98	memset(&regs, 0, sizeof(regs));
 99
100        /* Don't use r10 since that is set to 0 in copy_thread */
101	regs.r11 = (unsigned long)fn;
102	regs.r12 = (unsigned long)arg;
103	regs.irp = (unsigned long)kernel_thread_helper;
104
105	/* Ok, create the new process.. */
106        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
107}
108
109/* setup the child's kernel stack with a pt_regs and switch_stack on it.
110 * it will be un-nested during _resume and _ret_from_sys_call when the
111 * new thread is scheduled.
112 *
113 * also setup the thread switching structure which is used to keep
114 * thread-specific data during _resumes.
115 *
116 */
117asmlinkage void ret_from_fork(void);
118
119int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
120		unsigned long unused,
121		struct task_struct *p, struct pt_regs *regs)
122{
123	struct pt_regs * childregs;
124	struct switch_stack *swstack;
125	
126	/* put the pt_regs structure at the end of the new kernel stack page and fix it up
127	 * remember that the task_struct doubles as the kernel stack for the task
128	 */
129
130	childregs = user_regs(p->thread_info);        
131        
132	*childregs = *regs;  /* struct copy of pt_regs */
133        
134        p->set_child_tid = p->clear_child_tid = NULL;
135
136        childregs->r10 = 0;  /* child returns 0 after a fork/clone */
137	
138	/* put the switch stack right below the pt_regs */
139
140	swstack = ((struct switch_stack *)childregs) - 1;
141
142	swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
143
144	/* we want to return into ret_from_sys_call after the _resume */
145
146	swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
147	
148	/* fix the user-mode stackpointer */
149
150	p->thread.usp = usp;	
151
152	/* and the kernel-mode one */
153
154	p->thread.ksp = (unsigned long) swstack;
155
156#ifdef DEBUG
157	printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
158	show_registers(childregs);
159#endif
160
161	return 0;
162}
163
164/* 
165 * Be aware of the "magic" 7th argument in the four system-calls below.
166 * They need the latest stackframe, which is put as the 7th argument by
167 * entry.S. The previous arguments are dummies or actually used, but need
168 * to be defined to reach the 7th argument.
169 *
170 * N.B.: Another method to get the stackframe is to use current_regs(). But
171 * it returns the latest stack-frame stacked when going from _user mode_ and
172 * some of these (at least sys_clone) are called from kernel-mode sometimes
173 * (for example during kernel_thread, above) and thus cannot use it. Thus,
174 * to be sure not to get any surprises, we use the method for the other calls
175 * as well.
176 */
177
178asmlinkage int sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
179			struct pt_regs *regs)
180{
181	return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
182}
183
184/* if newusp is 0, we just grab the old usp */
185/* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
186asmlinkage int sys_clone(unsigned long newusp, unsigned long flags,
187			 int* parent_tid, int* child_tid, long mof, long srp,
188			 struct pt_regs *regs)
189{
190	if (!newusp)
191		newusp = rdusp();
192	return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
193}
194
195/* vfork is a system call in i386 because of register-pressure - maybe
196 * we can remove it and handle it in libc but we put it here until then.
197 */
198
199asmlinkage int sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
200			 struct pt_regs *regs)
201{
202        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
203}
204
205/*
206 * sys_execve() executes a new program.
207 */
208asmlinkage int sys_execve(const char *fname, char **argv, char **envp,
209			  long r13, long mof, long srp, 
210			  struct pt_regs *regs)
211{
212	int error;
213	char *filename;
214
215	filename = getname(fname);
216	error = PTR_ERR(filename);
217
218	if (IS_ERR(filename))
219	        goto out;
220	error = do_execve(filename, argv, envp, regs);
221	putname(filename);
222 out:
223	return error;
224}
225
226unsigned long get_wchan(struct task_struct *p)
227{
228#if 0
229	/* YURGH. TODO. */
230
231        unsigned long ebp, esp, eip;
232        unsigned long stack_page;
233        int count = 0;
234        if (!p || p == current || p->state == TASK_RUNNING)
235                return 0;
236        stack_page = (unsigned long)p;
237        esp = p->thread.esp;
238        if (!stack_page || esp < stack_page || esp > 8188+stack_page)
239                return 0;
240        /* include/asm-i386/system.h:switch_to() pushes ebp last. */
241        ebp = *(unsigned long *) esp;
242        do {
243                if (ebp < stack_page || ebp > 8184+stack_page)
244                        return 0;
245                eip = *(unsigned long *) (ebp+4);
246		if (!in_sched_functions(eip))
247			return eip;
248                ebp = *(unsigned long *) ebp;
249        } while (count++ < 16);
250#endif
251        return 0;
252}
253#undef last_sched
254#undef first_sched
255
256void show_regs(struct pt_regs * regs)
257{
258	unsigned long usp = rdusp();
259	printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
260	       regs->irp, regs->srp, regs->dccr, usp, regs->mof );
261	printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
262	       regs->r0, regs->r1, regs->r2, regs->r3);
263	printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
264	       regs->r4, regs->r5, regs->r6, regs->r7);
265	printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
266	       regs->r8, regs->r9, regs->r10, regs->r11);
267	printk("r12: %08lx r13: %08lx oR10: %08lx\n",
268	       regs->r12, regs->r13, regs->orig_r10);
269}
270