aboutsummaryrefslogtreecommitdiff
path: root/arch/avr32/kernel/process.c
blob: ff820a9e743a01c3d5fdd7bd61649fec474bdad3 (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
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/fs.h>
#include <linux/ptrace.h>
#include <linux/reboot.h>
#include <linux/tick.h>
#include <linux/uaccess.h>
#include <linux/unistd.h>

#include <asm/sysreg.h>
#include <asm/ocd.h>

#include <asm/arch/pm.h>

void (*pm_power_off)(void) = NULL;
EXPORT_SYMBOL(pm_power_off);

/*
 * This file handles the architecture-dependent parts of process handling..
 */

void cpu_idle(void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		tick_nohz_stop_sched_tick(1);
		while (!need_resched())
			cpu_idle_sleep();
		tick_nohz_restart_sched_tick();
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}

void machine_halt(void)
{
	/*
	 * Enter Stop mode. The 32 kHz oscillator will keep running so
	 * the RTC will keep the time properly and the system will
	 * boot quickly.
	 */
	asm volatile("sleep 3\n\t"
		     "sub pc, -2");
}

void machine_power_off(void)
{
	if (pm_power_off)
		pm_power_off();
}

void machine_restart(char *cmd)
{
	ocd_write(DC, (1 << OCD_DC_DBE_BIT));
	ocd_write(DC, (1 << OCD_DC_RES_BIT));
	while (1) ;
}

/*
 * PC is actually discarded when returning from a system call -- the
 * return address must be stored in LR. This function will make sure
 * LR points to do_exit before starting the thread.
 *
 * Also, when returning from fork(), r12 is 0, so we must copy the
 * argument as well.
 *
 *  r0 : The argument to the main thread function
 *  r1 : The address of do_exit
 *  r2 : The address of the main thread function
 */
asmlinkage extern void kernel_thread_helper(void);
__asm__("	.type	kernel_thread_helper, @function\n"
	"kernel_thread_helper:\n"
	"	mov	r12, r0\n"
	"	mov	lr, r2\n"
	"	mov	pc, r1\n"
	"	.size	kernel_thread_helper, . - kernel_thread_helper");

int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
	struct pt_regs regs;

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

	regs.r0 = (unsigned long)arg;
	regs.r1 = (unsigned long)fn;
	regs.r2 = (unsigned long)do_exit;
	regs.lr = (unsigned long)kernel_thread_helper;
	regs.pc = (unsigned long)kernel_thread_helper;
	regs.sr = MODE_SUPERVISOR;

	return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
		       0, &regs, 0, NULL, NULL);
}
EXPORT_SYMBOL(kernel_thread);

/*
 * Free current thread data structures etc
 */
void exit_thread(void)
{
	ocd_disable(current);
}

void flush_thread(void)
{
	/* nothing to do */
}

void release_thread(struct task_struct *dead_task)
{
	/* do nothing */
}

static void dump_mem(const char *str, const char *log_lvl,
		     unsigned long bottom, unsigned long top)
{
	unsigned long p;
	int i;

	printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);

	for (p = bottom & ~31; p < top; ) {
		printk("%s%04lx: ", log_lvl, p & 0xffff);

		for (i = 0; i < 8; i++, p += 4) {
			unsigned int val;

			if (p < bottom || p >= top)
				printk("         ");
			else {
				if (__get_user(val, (unsigned int __user *)p)) {
					printk("\n");
					goto out;
				}
				printk("%08x ", val);
			}
		}
		printk("\n");
	}

out:
	return;
}

static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
{
	return (p > (unsigned long)tinfo)
		&& (p < (unsigned long)tinfo + THREAD_SIZE - 3);
}

#ifdef CONFIG_FRAME_POINTER
static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
			       struct pt_regs *regs, const char *log_lvl)
{
	unsigned long lr, fp;
	struct thread_info *tinfo;

	if (regs)
		fp = regs->r7;
	else if (tsk == current)
		asm("mov %0, r7" : "=r"(fp));
	else
		fp = tsk->thread.cpu_context.r7;

	/*
	 * Walk the stack as long as the frame pointer (a) is within
	 * the kernel stack of the task, and (b) it doesn't move
	 * downwards.
	 */
	tinfo = task_thread_info(tsk);
	printk("%sCall trace:\n", log_lvl);
	while (valid_stack_ptr(tinfo, fp)) {
		unsigned long new_fp;

		lr = *(unsigned long *)fp;
#ifdef CONFIG_KALLSYMS
		printk("%s [<%08lx>] ", log_lvl, lr);
#else
		printk(" [<%08lx>] ", lr);
#endif
		print_symbol("%s\n", lr);

		new_fp = *(unsigned long *)(fp + 4);
		if (new_fp <= fp)
			break;
		fp = new_fp;
	}
	printk("\n");
}
#else
static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
			       struct pt_regs *regs, const char *log_lvl)
{
	unsigned long addr;

	printk("%sCall trace:\n", log_lvl);

	while (!kstack_end(sp)) {
		addr = *sp++;
		if (kernel_text_address(addr)) {
#ifdef CONFIG_KALLSYMS
			printk("%s [<%08lx>] ", log_lvl, addr);
#else
			printk(" [<%08lx>] ", addr);
#endif
			print_symbol("%s\n", addr);
		}
	}
	printk("\n");
}
#endif

void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
			struct pt_regs *regs, const char *log_lvl)
{
	struct thread_info *tinfo;

	if (sp == 0) {
		if (tsk)
			sp = tsk->thread.cpu_context.ksp;
		else
			sp = (unsigned long)&tinfo;
	}
	if (!tsk)
		tsk = current;

	tinfo = task_thread_info(tsk);

	if (valid_stack_ptr(tinfo, sp)) {
		dump_mem("Stack: ", log_lvl, sp,
			 THREAD_SIZE + (unsigned long)tinfo);
		show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
	}
}

void show_stack(struct task_struct *tsk, unsigned long *stack)
{
	show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
}

void dump_stack(void)
{
	unsigned long stack;

	show_trace_log_lvl(current, &stack, NULL, "");
}
EXPORT_SYMBOL(dump_stack);

static const char *cpu_modes[] = {
	"Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
	"Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
};

void show_regs_log_lvl(struct pt_regs *regs, const char *log_lvl)
{
	unsigned long sp = regs->sp;
	unsigned long lr = regs->lr;
	unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;

	if (!user_mode(regs)) {
		sp = (unsigned long)regs + FRAME_SIZE_FULL;

		printk("%s", log_lvl);
		print_symbol("PC is at %s\n", instruction_pointer(regs));
		printk("%s", log_lvl);
		print_symbol("LR is at %s\n", lr);
	}

	printk("%spc : [<%08lx>]    lr : [<%08lx>]    %s\n"
	       "%ssp : %08lx  r12: %08lx  r11: %08lx\n",
	       log_lvl, instruction_pointer(regs), lr, print_tainted(),
	       log_lvl, sp, regs->r12, regs->r11);
	printk("%sr10: %08lx  r9 : %08lx  r8 : %08lx\n",
	       log_lvl, regs->r10, regs->r9, regs->r8);
	printk("%sr7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
	       log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
	printk("%sr3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
	       log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
	printk("%sFlags: %c%c%c%c%c\n", log_lvl,
	       regs->sr & SR_Q ? 'Q' : 'q',
	       regs->sr & SR_V ? 'V' : 'v',
	       regs->sr & SR_N ? 'N' : 'n',
	       regs->sr & SR_Z ? 'Z' : 'z',
	       regs->sr & SR_C ? 'C' : 'c');
	printk("%sMode bits: %c%c%c%c%c%c%c%c%c%c\n", log_lvl,
	       regs->sr & SR_H ? 'H' : 'h',
	       regs->sr & SR_J ? 'J' : 'j',
	       regs->sr & SR_DM ? 'M' : 'm',
	       regs->sr & SR_D ? 'D' : 'd',
	       regs->sr & SR_EM ? 'E' : 'e',
	       regs->sr & SR_I3M ? '3' : '.',
	       regs->sr & SR_I2M ? '2' : '.',
	       regs->sr & SR_I1M ? '1' : '.',
	       regs->sr & SR_I0M ? '0' : '.',
	       regs->sr & SR_GM ? 'G' : 'g');
	printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
	printk("%sProcess: %s [%d] (task: %p thread: %p)\n",
	       log_lvl, current->comm, current->pid, current,
	       task_thread_info(current));
}

void show_regs(struct pt_regs *regs)
{
	unsigned long sp = regs->sp;

	if (!user_mode(regs))
		sp = (unsigned long)regs + FRAME_SIZE_FULL;

	show_regs_log_lvl(regs, "");
	show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
}
EXPORT_SYMBOL(show_regs);

/* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
	/* Not valid */
	return 0;
}

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;

	childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
	*childregs = *regs;

	if (user_mode(regs))
		childregs->sp = usp;
	else
		childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;

	childregs->r12 = 0; /* Set return value for child */

	p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
	p->thread.cpu_context.ksp = (unsigned long)childregs;
	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;

	clear_tsk_thread_flag(p, TIF_DEBUG);
	if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
		ocd_enable(p);

	return 0;
}

/* r12-r8 are dummy parameters to force the compiler to use the stack */
asmlinkage int sys_fork(struct pt_regs *regs)
{
	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
}

asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
			 unsigned long parent_tidptr,
			 unsigned long child_tidptr, struct pt_regs *regs)
{
	if (!newsp)
		newsp = regs->sp;
	return do_fork(clone_flags, newsp, regs, 0,
		       (int __user *)parent_tidptr,
		       (int __user *)child_tidptr);
}

asmlinkage int sys_vfork(struct pt_regs *regs)
{
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
		       0, NULL, NULL);
}

asmlinkage int sys_execve(char __user *ufilename, char __user *__user *uargv,
			  char __user *__user *uenvp, struct pt_regs *regs)
{
	int error;
	char *filename;

	filename = getname(ufilename);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		goto out;

	error = do_execve(filename, uargv, uenvp, regs);
	if (error == 0)
		current->ptrace &= ~PT_DTRACE;
	putname(filename);

out:
	return error;
}


/*
 * This function is supposed to answer the question "who called
 * schedule()?"
 */
unsigned long get_wchan(struct task_struct *p)
{
	unsigned long pc;
	unsigned long stack_page;

	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;

	stack_page = (unsigned long)task_stack_page(p);
	BUG_ON(!stack_page);

	/*
	 * The stored value of PC is either the address right after
	 * the call to __switch_to() or ret_from_fork.
	 */
	pc = thread_saved_pc(p);
	if (in_sched_functions(pc)) {
#ifdef CONFIG_FRAME_POINTER
		unsigned long fp = p->thread.cpu_context.r7;
		BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
		pc = *(unsigned long *)fp;
#else
		/*
		 * We depend on the frame size of schedule here, which
		 * is actually quite ugly. It might be possible to
		 * determine the frame size automatically at build
		 * time by doing this:
		 *   - compile sched.c
		 *   - disassemble the resulting sched.o
		 *   - look for 'sub sp,??' shortly after '<schedule>:'
		 */
		unsigned long sp = p->thread.cpu_context.ksp + 16;
		BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
		pc = *(unsigned long *)sp;
#endif
	}

	return pc;
}