aboutsummaryrefslogtreecommitdiff
path: root/arch/m68k/kernel/process.c
blob: 1a6be27cf165a0cd60c210e72abcf727c981c462 (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
/*
 *  linux/arch/m68k/kernel/process.c
 *
 *  Copyright (C) 1995  Hamish Macdonald
 *
 *  68060 fixes by Jesper Skov
 */

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

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/reboot.h>
#include <linux/init_task.h>
#include <linux/mqueue.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/traps.h>
#include <asm/machdep.h>
#include <asm/setup.h>
#include <asm/pgtable.h>

/*
 * Initial task/thread structure. Make this a per-architecture thing,
 * because different architectures tend to have different
 * alignment requirements and potentially different initial
 * setup.
 */
static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
union thread_union init_thread_union __init_task_data
	__attribute__((aligned(THREAD_SIZE))) =
		{ INIT_THREAD_INFO(init_task) };

/* initial task structure */
struct task_struct init_task = INIT_TASK(init_task);

EXPORT_SYMBOL(init_task);

asmlinkage void ret_from_fork(void);


/*
 * Return saved PC from a blocked thread
 */
unsigned long thread_saved_pc(struct task_struct *tsk)
{
	struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
	/* Check whether the thread is blocked in resume() */
	if (in_sched_functions(sw->retpc))
		return ((unsigned long *)sw->a6)[1];
	else
		return sw->retpc;
}

/*
 * The idle loop on an m68k..
 */
static void default_idle(void)
{
	if (!need_resched())
#if defined(MACH_ATARI_ONLY)
		/* block out HSYNC on the atari (falcon) */
		__asm__("stop #0x2200" : : : "cc");
#else
		__asm__("stop #0x2000" : : : "cc");
#endif
}

void (*idle)(void) = default_idle;

/*
 * The idle thread. There's no useful work to be
 * done, so just try to conserve power and have a
 * low exit latency (ie sit in a loop waiting for
 * somebody to say that they'd like to reschedule)
 */
void cpu_idle(void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		while (!need_resched())
			idle();
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}

void machine_restart(char * __unused)
{
	if (mach_reset)
		mach_reset();
	for (;;);
}

void machine_halt(void)
{
	if (mach_halt)
		mach_halt();
	for (;;);
}

void machine_power_off(void)
{
	if (mach_power_off)
		mach_power_off();
	for (;;);
}

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

void show_regs(struct pt_regs * regs)
{
	printk("\n");
	printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
	       regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
	printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
	       regs->orig_d0, regs->d0, regs->a2, regs->a1);
	printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
	       regs->a0, regs->d5, regs->d4);
	printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
	       regs->d3, regs->d2, regs->d1);
	if (!(regs->sr & PS_S))
		printk("USP: %08lx\n", rdusp());
}

/*
 * Create a kernel thread
 */
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
	int pid;
	mm_segment_t fs;

	fs = get_fs();
	set_fs (KERNEL_DS);

	{
	register long retval __asm__ ("d0");
	register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;

	retval = __NR_clone;
	__asm__ __volatile__
	  ("clrl %%d2\n\t"
	   "trap #0\n\t"		/* Linux/m68k system call */
	   "tstl %0\n\t"		/* child or parent */
	   "jne 1f\n\t"			/* parent - jump */
	   "lea %%sp@(%c7),%6\n\t"	/* reload current */
	   "movel %6@,%6\n\t"
	   "movel %3,%%sp@-\n\t"	/* push argument */
	   "jsr %4@\n\t"		/* call fn */
	   "movel %0,%%d1\n\t"		/* pass exit value */
	   "movel %2,%%d0\n\t"		/* exit */
	   "trap #0\n"
	   "1:"
	   : "+d" (retval)
	   : "i" (__NR_clone), "i" (__NR_exit),
	     "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
	     "i" (-THREAD_SIZE)
	   : "d2");

	pid = retval;
	}

	set_fs (fs);
	return pid;
}
EXPORT_SYMBOL(kernel_thread);

void flush_thread(void)
{
	unsigned long zero = 0;
	set_fs(USER_DS);
	current->thread.fs = __USER_DS;
	if (!FPU_IS_EMU)
		asm volatile (".chip 68k/68881\n\t"
			      "frestore %0@\n\t"
			      ".chip 68k" : : "a" (&zero));
}

/*
 * "m68k_fork()".. By the time we get here, the
 * non-volatile registers have also been saved on the
 * stack. We do some ugly pointer stuff here.. (see
 * also copy_thread)
 */

asmlinkage int m68k_fork(struct pt_regs *regs)
{
	return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
}

asmlinkage int m68k_vfork(struct pt_regs *regs)
{
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
		       NULL, NULL);
}

asmlinkage int m68k_clone(struct pt_regs *regs)
{
	unsigned long clone_flags;
	unsigned long newsp;
	int __user *parent_tidptr, *child_tidptr;

	/* syscall2 puts clone_flags in d1 and usp in d2 */
	clone_flags = regs->d1;
	newsp = regs->d2;
	parent_tidptr = (int __user *)regs->d3;
	child_tidptr = (int __user *)regs->d4;
	if (!newsp)
		newsp = rdusp();
	return do_fork(clone_flags, newsp, regs, 0,
		       parent_tidptr, child_tidptr);
}

int copy_thread(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 * childstack, *stack;
	unsigned long *retp;

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

	*childregs = *regs;
	childregs->d0 = 0;

	retp = ((unsigned long *) regs);
	stack = ((struct switch_stack *) retp) - 1;

	childstack = ((struct switch_stack *) childregs) - 1;
	*childstack = *stack;
	childstack->retpc = (unsigned long)ret_from_fork;

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

	if (clone_flags & CLONE_SETTLS)
		task_thread_info(p)->tp_value = regs->d5;

	/*
	 * Must save the current SFC/DFC value, NOT the value when
	 * the parent was last descheduled - RGH  10-08-96
	 */
	p->thread.fs = get_fs().seg;

	if (!FPU_IS_EMU) {
		/* Copy the current fpu state */
		asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");

		if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2])
		  asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
				"fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
				: : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
				: "memory");
		/* Restore the state in case the fpu was busy */
		asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
	}

	return 0;
}

/* Fill in the fpu structure for a core dump.  */

int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
{
	char fpustate[216];

	if (FPU_IS_EMU) {
		int i;

		memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
		memcpy(fpu->fpregs, current->thread.fp, 96);
		/* Convert internal fpu reg representation
		 * into long double format
		 */
		for (i = 0; i < 24; i += 3)
			fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
			                 ((fpu->fpregs[i] & 0x0000ffff) << 16);
		return 1;
	}

	/* First dump the fpu context to avoid protocol violation.  */
	asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
	if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
		return 0;

	asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
		:: "m" (fpu->fpcntl[0])
		: "memory");
	asm volatile ("fmovemx %/fp0-%/fp7,%0"
		:: "m" (fpu->fpregs[0])
		: "memory");
	return 1;
}
EXPORT_SYMBOL(dump_fpu);

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
{
	int error;
	char * filename;
	struct pt_regs *regs = (struct pt_regs *) &name;

	filename = getname(name);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		return error;
	error = do_execve(filename, argv, envp, regs);
	putname(filename);
	return error;
}

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

	stack_page = (unsigned long)task_stack_page(p);
	fp = ((struct switch_stack *)p->thread.ksp)->a6;
	do {
		if (fp < stack_page+sizeof(struct thread_info) ||
		    fp >= 8184+stack_page)
			return 0;
		pc = ((unsigned long *)fp)[1];
		if (!in_sched_functions(pc))
			return pc;
		fp = *(unsigned long *) fp;
	} while (count++ < 16);
	return 0;
}