summaryrefslogtreecommitdiffstats
path: root/arch/arm26/kernel/process.c
blob: 38630565917142c4b4bb2c5017141e71ecfb06cc (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
/*
 *  linux/arch/arm26/kernel/process.c
 *
 *  Copyright (C) 2003 Ian Molton - adapted for ARM26
 *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
 *  Origional Copyright (C) 1995  Linus Torvalds
 *
 * 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 <stdarg.h>

#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/interrupt.h>
#include <linux/init.h>

#include <asm/system.h>
#include <asm/io.h>
#include <asm/leds.h>
#include <asm/processor.h>
#include <asm/uaccess.h>

extern const char *processor_modes[];
extern void setup_mm_for_reboot(char mode);

static volatile int hlt_counter;

void disable_hlt(void)
{
	hlt_counter++;
}

EXPORT_SYMBOL(disable_hlt);

void enable_hlt(void)
{
	hlt_counter--;
}

EXPORT_SYMBOL(enable_hlt);

static int __init nohlt_setup(char *__unused)
{
	hlt_counter = 1;
	return 1;
}

static int __init hlt_setup(char *__unused)
{
	hlt_counter = 0;
	return 1;
}

__setup("nohlt", nohlt_setup);
__setup("hlt", hlt_setup);

/*
 * This is our default idle handler.  We need to disable
 * interrupts here to ensure we don't miss a wakeup call.
 */
void cpu_idle(void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		while (!need_resched())
			cpu_relax();
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}

static char reboot_mode = 'h';

int __init reboot_setup(char *str)
{
	reboot_mode = str[0];
	return 1;
}

__setup("reboot=", reboot_setup);

/* ARM26 cant do these but we still need to define them. */
void machine_halt(void)
{
}
void machine_power_off(void)
{
}

void machine_restart(char * __unused)
{
	/*
	 * Clean and disable cache, and turn off interrupts
	 */
	cpu_proc_fin();

	/*
	 * Tell the mm system that we are going to reboot -
	 * we may need it to insert some 1:1 mappings so that
	 * soft boot works.
	 */
	setup_mm_for_reboot(reboot_mode);

	/*
         * copy branch instruction to reset location and call it
         */

        *(unsigned long *)0 = *(unsigned long *)0x03800000;
        ((void(*)(void))0)();

	/*
	 * Whoops - the architecture was unable to reboot.
	 * Tell the user! Should never happen...
	 */
	mdelay(1000);
	printk("Reboot failed -- System halted\n");
	while (1);
}

void show_regs(struct pt_regs * regs)
{
	unsigned long flags;

	flags = condition_codes(regs);

	printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
	       "sp : %08lx  ip : %08lx  fp : %08lx\n",
		instruction_pointer(regs),
		regs->ARM_lr, print_tainted(), regs->ARM_sp,
		regs->ARM_ip, regs->ARM_fp);
	printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
		regs->ARM_r10, regs->ARM_r9,
		regs->ARM_r8);
	printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
		regs->ARM_r7, regs->ARM_r6,
		regs->ARM_r5, regs->ARM_r4);
	printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
		regs->ARM_r3, regs->ARM_r2,
		regs->ARM_r1, regs->ARM_r0);
	printk("Flags: %c%c%c%c",
		flags & PSR_N_BIT ? 'N' : 'n',
		flags & PSR_Z_BIT ? 'Z' : 'z',
		flags & PSR_C_BIT ? 'C' : 'c',
		flags & PSR_V_BIT ? 'V' : 'v');
	printk("  IRQs o%s  FIQs o%s  Mode %s  Segment %s\n",
		interrupts_enabled(regs) ? "n" : "ff",
		fast_interrupts_enabled(regs) ? "n" : "ff",
		processor_modes[processor_mode(regs)],
		get_fs() == get_ds() ? "kernel" : "user");
}

void show_fpregs(struct user_fp *regs)
{
	int i;

	for (i = 0; i < 8; i++) {
		unsigned long *p;
		char type;

		p = (unsigned long *)(regs->fpregs + i);

		switch (regs->ftype[i]) {
			case 1: type = 'f'; break;
			case 2: type = 'd'; break;
			case 3: type = 'e'; break;
			default: type = '?'; break;
		}
		if (regs->init_flag)
			type = '?';

		printk("  f%d(%c): %08lx %08lx %08lx%c",
			i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
	}
			

	printk("FPSR: %08lx FPCR: %08lx\n",
		(unsigned long)regs->fpsr,
		(unsigned long)regs->fpcr);
}

/*
 * Task structure and kernel stack allocation.
 */
static unsigned long *thread_info_head;
static unsigned int nr_thread_info;

extern unsigned long get_page_8k(int priority);
extern void free_page_8k(unsigned long page);

// FIXME - is this valid?
#define EXTRA_TASK_STRUCT	0
#define ll_alloc_task_struct()	((struct thread_info *)get_page_8k(GFP_KERNEL))
#define ll_free_task_struct(p)  free_page_8k((unsigned long)(p))

//FIXME - do we use *task param below looks like we dont, which is ok?
//FIXME - if EXTRA_TASK_STRUCT is zero we can optimise the below away permanently. *IF* its supposed to be zero.
struct thread_info *alloc_thread_info(struct task_struct *task)
{
	struct thread_info *thread = NULL;

	if (EXTRA_TASK_STRUCT) {
		unsigned long *p = thread_info_head;

		if (p) {
			thread_info_head = (unsigned long *)p[0];
			nr_thread_info -= 1;
		}
		thread = (struct thread_info *)p;
	}

	if (!thread)
		thread = ll_alloc_task_struct();

#ifdef CONFIG_MAGIC_SYSRQ
	/*
	 * The stack must be cleared if you want SYSRQ-T to
	 * give sensible stack usage information
	 */
	if (thread) {
		char *p = (char *)thread;
		memzero(p+KERNEL_STACK_SIZE, KERNEL_STACK_SIZE);
	}
#endif
	return thread;
}

void free_thread_info(struct thread_info *thread)
{
	if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
		unsigned long *p = (unsigned long *)thread;
		p[0] = (unsigned long)thread_info_head;
		thread_info_head = p;
		nr_thread_info += 1;
	} else
		ll_free_task_struct(thread);
}

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

void flush_thread(void)
{
	struct thread_info *thread = current_thread_info();
	struct task_struct *tsk = current;

	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
	memset(&thread->fpstate, 0, sizeof(union fp_state));

	clear_used_math();
}

void release_thread(struct task_struct *dead_task)
{
}

asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");

int
copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
	    unsigned long unused, struct task_struct *p, struct pt_regs *regs)
{
	struct thread_info *thread = task_thread_info(p);
	struct pt_regs *childregs = task_pt_regs(p);

	*childregs = *regs;
	childregs->ARM_r0 = 0;
	childregs->ARM_sp = stack_start;

	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
	thread->cpu_context.sp = (unsigned long)childregs;
	thread->cpu_context.pc = (unsigned long)ret_from_fork | MODE_SVC26 | PSR_I_BIT;

	return 0;
}

/*
 * fill in the fpe structure for a core dump...
 */
int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
{
	struct thread_info *thread = current_thread_info();
	int used_math = !!used_math();

	if (used_math)
		memcpy(fp, &thread->fpstate.soft, sizeof (*fp));

	return used_math;
}

/*
 * fill in the user structure for a core dump..
 */
void dump_thread(struct pt_regs * regs, struct user * dump)
{
	struct task_struct *tsk = current;

	dump->magic = CMAGIC;
	dump->start_code = tsk->mm->start_code;
	dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);

	dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
	dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
	dump->u_ssize = 0;

	dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
	dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
	dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn;
	dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn;
	dump->u_debugreg[4] = tsk->thread.debug.nsaved;

	if (dump->start_stack < 0x04000000)
		dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;

	dump->regs = *regs;
	dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
}

/*
 * Shuffle the argument into the correct register before calling the
 * thread function.  r1 is the thread argument, r2 is the pointer to
 * the thread function, and r3 points to the exit function.
 * FIXME - make sure this is right - the older code used to zero fp
 * and cause the parent to call sys_exit (do_exit in this version)
 */
extern void kernel_thread_helper(void);

asm(    ".section .text\n"
"       .align\n"
"       .type   kernel_thread_helper, #function\n"
"kernel_thread_helper:\n"
"       mov     r0, r1\n"
"       mov     lr, r3\n"
"       mov     pc, r2\n"
"       .size   kernel_thread_helper, . - kernel_thread_helper\n"
"       .previous");

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

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

        regs.ARM_r1 = (unsigned long)arg;
        regs.ARM_r2 = (unsigned long)fn;
        regs.ARM_r3 = (unsigned long)do_exit;
        regs.ARM_pc = (unsigned long)kernel_thread_helper | MODE_SVC26;

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


unsigned long get_wchan(struct task_struct *p)
{
	unsigned long fp, lr;
	unsigned long stack_page;
	int count = 0;
	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;

	stack_page = 4096 + (unsigned long)p;
	fp = thread_saved_fp(p);
	do {
		if (fp < stack_page || fp > 4092+stack_page)
			return 0;
		lr = pc_pointer (((unsigned long *)fp)[-1]);
		if (!in_sched_functions(lr))
			return lr;
		fp = *(unsigned long *) (fp - 12);
	} while (count ++ < 16);
	return 0;
}
OpenPOWER on IntegriCloud