summaryrefslogtreecommitdiff
path: root/arch/cris/arch-v10/kernel/process.c
blob: bd9b3ff63f6c7b772ce89b8bd1df0e9934b75d06 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
/*
 *  linux/arch/cris/kernel/process.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *  Copyright (C) 2000-2002  Axis Communications AB
 *
 *  Authors:   Bjorn Wesen (bjornw@axis.com)
 *             Mikael Starvik (starvik@axis.com)
 *
 * This file handles the architecture-dependent parts of process handling..
 */

#include <linux/sched.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <arch/svinto.h>
#include <linux/init.h>

#ifdef CONFIG_ETRAX_GPIO
void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
#endif

/*
 * We use this if we don't have any better
 * idle routine..
 */
void default_idle(void)
{
#ifdef CONFIG_ETRAX_GPIO
  etrax_gpio_wake_up_check();
#endif
}

/*
 * Free current thread data structures etc..
 */

void exit_thread(void)
{
	/* Nothing needs to be done.  */
}

/* if the watchdog is enabled, we can simply disable interrupts and go
 * into an eternal loop, and the watchdog will reset the CPU after 0.1s
 * if on the other hand the watchdog wasn't enabled, we just enable it and wait
 */

void hard_reset_now (void)
{
	/*
	 * Don't declare this variable elsewhere.  We don't want any other
	 * code to know about it than the watchdog handler in entry.S and
	 * this code, implementing hard reset through the watchdog.
	 */
#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
	extern int cause_of_death;
#endif

	printk("*** HARD RESET ***\n");
	local_irq_disable();

#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
	cause_of_death = 0xbedead;
#else
	/* Since we dont plan to keep on resetting the watchdog,
	   the key can be arbitrary hence three */
	*R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) |
		IO_STATE(R_WATCHDOG, enable, start);
#endif

	while(1) /* waiting for RETRIBUTION! */ ;
}

/*
 * Return saved PC of a blocked thread.
 */
unsigned long thread_saved_pc(struct task_struct *t)
{
	return task_pt_regs(t)->irp;
}

static void kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
{
  fn(arg);
  do_exit(-1); /* Should never be called, return bad exit value */
}

/*
 * Create a kernel thread
 */
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
	struct pt_regs regs;

	memset(&regs, 0, sizeof(regs));

        /* Don't use r10 since that is set to 0 in copy_thread */
	regs.r11 = (unsigned long)fn;
	regs.r12 = (unsigned long)arg;
	regs.irp = (unsigned long)kernel_thread_helper;
	regs.dccr = 1 << I_DCCR_BITNR;

	/* Ok, create the new process.. */
        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
}

/* setup the child's kernel stack with a pt_regs and switch_stack on it.
 * it will be un-nested during _resume and _ret_from_sys_call when the
 * new thread is scheduled.
 *
 * also setup the thread switching structure which is used to keep
 * thread-specific data during _resumes.
 *
 */
asmlinkage void ret_from_fork(void);

int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
		unsigned long unused,
		struct task_struct *p, struct pt_regs *regs)
{
	struct pt_regs * childregs;
	struct switch_stack *swstack;
	
	/* put the pt_regs structure at the end of the new kernel stack page and fix it up
	 * remember that the task_struct doubles as the kernel stack for the task
	 */

	childregs = task_pt_regs(p);
        
	*childregs = *regs;  /* struct copy of pt_regs */
        
        p->set_child_tid = p->clear_child_tid = NULL;

        childregs->r10 = 0;  /* child returns 0 after a fork/clone */
	
	/* put the switch stack right below the pt_regs */

	swstack = ((struct switch_stack *)childregs) - 1;

	swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */

	/* we want to return into ret_from_sys_call after the _resume */

	swstack->return_ip = (unsigned long) ret_from_fork; /* Will call ret_from_sys_call */
	
	/* fix the user-mode stackpointer */

	p->thread.usp = usp;	

	/* and the kernel-mode one */

	p->thread.ksp = (unsigned long) swstack;

#ifdef DEBUG
	printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs);
	show_registers(childregs);
#endif

	return 0;
}

/* 
 * Be aware of the "magic" 7th argument in the four system-calls below.
 * They need the latest stackframe, which is put as the 7th argument by
 * entry.S. The previous arguments are dummies or actually used, but need
 * to be defined to reach the 7th argument.
 *
 * N.B.: Another method to get the stackframe is to use current_regs(). But
 * it returns the latest stack-frame stacked when going from _user mode_ and
 * some of these (at least sys_clone) are called from kernel-mode sometimes
 * (for example during kernel_thread, above) and thus cannot use it. Thus,
 * to be sure not to get any surprises, we use the method for the other calls
 * as well.
 */

asmlinkage int sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
			struct pt_regs *regs)
{
	return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
}

/* if newusp is 0, we just grab the old usp */
/* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
asmlinkage int sys_clone(unsigned long newusp, unsigned long flags,
			 int* parent_tid, int* child_tid, long mof, long srp,
			 struct pt_regs *regs)
{
	if (!newusp)
		newusp = rdusp();
	return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
}

/* vfork is a system call in i386 because of register-pressure - maybe
 * we can remove it and handle it in libc but we put it here until then.
 */

asmlinkage int sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
			 struct pt_regs *regs)
{
        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(const char *fname, char **argv, char **envp,
			  long r13, long mof, long srp, 
			  struct pt_regs *regs)
{
	int error;
	char *filename;

	filename = getname(fname);
	error = PTR_ERR(filename);

	if (IS_ERR(filename))
	        goto out;
	error = do_execve(filename, argv, envp, regs);
	putname(filename);
 out:
	return error;
}

unsigned long get_wchan(struct task_struct *p)
{
#if 0
	/* YURGH. TODO. */

        unsigned long ebp, esp, eip;
        unsigned long stack_page;
        int count = 0;
        if (!p || p == current || p->state == TASK_RUNNING)
                return 0;
        stack_page = (unsigned long)p;
        esp = p->thread.esp;
        if (!stack_page || esp < stack_page || esp > 8188+stack_page)
                return 0;
        /* include/asm-i386/system.h:switch_to() pushes ebp last. */
        ebp = *(unsigned long *) esp;
        do {
                if (ebp < stack_page || ebp > 8184+stack_page)
                        return 0;
                eip = *(unsigned long *) (ebp+4);
		if (!in_sched_functions(eip))
			return eip;
                ebp = *(unsigned long *) ebp;
        } while (count++ < 16);
#endif
        return 0;
}
#undef last_sched
#undef first_sched

void show_regs(struct pt_regs * regs)
{
	unsigned long usp = rdusp();
	printk("IRP: %08lx SRP: %08lx DCCR: %08lx USP: %08lx MOF: %08lx\n",
	       regs->irp, regs->srp, regs->dccr, usp, regs->mof );
	printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
	       regs->r0, regs->r1, regs->r2, regs->r3);
	printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
	       regs->r4, regs->r5, regs->r6, regs->r7);
	printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
	       regs->r8, regs->r9, regs->r10, regs->r11);
	printk("r12: %08lx r13: %08lx oR10: %08lx\n",
	       regs->r12, regs->r13, regs->orig_r10);
}