summaryrefslogtreecommitdiff
path: root/arch/m68k/kernel/process.c
blob: aa9b11000273f8735c489dd4cf69b89227265dc0 (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
/*
 *  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/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 <linux/rcupdate.h>

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


asmlinkage void ret_from_fork(void);
asmlinkage void ret_from_kernel_thread(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) {
		rcu_idle_enter();
		while (!need_resched())
			idle();
		rcu_idle_exit();
		schedule_preempt_disabled();
	}
}

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());
}

void flush_thread(void)
{
	current->thread.fs = __USER_DS;
#ifdef CONFIG_FPU
	if (!FPU_IS_EMU) {
		unsigned long zero = 0;
		asm volatile("frestore %0": :"m" (zero));
	}
#endif
}

/*
 * Why not generic sys_clone, you ask?  m68k passes all arguments on stack.
 * And we need all registers saved, which means a bunch of stuff pushed
 * on top of pt_regs, which means that sys_clone() arguments would be
 * buried.  We could, of course, copy them, but it's too costly for no
 * good reason - generic clone() would have to copy them *again* for
 * do_fork() anyway.  So in this case it's actually better to pass pt_regs *
 * and extract arguments for do_fork() from there.  Eventually we might
 * go for calling do_fork() directly from the wrapper, but only after we
 * are finished with do_fork() prototype conversion.
 */
asmlinkage int m68k_clone(struct pt_regs *regs)
{
	/* regs will be equal to current_pt_regs() */
	return do_fork(regs->d1, regs->d2, regs, 0,
		       (int __user *)regs->d3, (int __user *)regs->d4);
}

int copy_thread(unsigned long clone_flags, unsigned long usp,
		 unsigned long arg,
		 struct task_struct * p, struct pt_regs * unused)
{
	struct fork_frame {
		struct switch_stack sw;
		struct pt_regs regs;
	} *frame;

	frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;

	p->thread.ksp = (unsigned long)frame;
	p->thread.esp0 = (unsigned long)&frame->regs;

	/*
	 * 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 (unlikely(p->flags & PF_KTHREAD)) {
		/* kernel thread */
		memset(frame, 0, sizeof(struct fork_frame));
		frame->regs.sr = PS_S;
		frame->sw.a3 = usp; /* function */
		frame->sw.d7 = arg;
		frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
		p->thread.usp = 0;
		return 0;
	}
	memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
		sizeof(struct fork_frame));
	frame->regs.d0 = 0;
	frame->sw.retpc = (unsigned long)ret_from_fork;
	p->thread.usp = usp ?: rdusp();

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

#ifdef CONFIG_FPU
	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]) {
			if (CPU_IS_COLDFIRE) {
				asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
					      "fmovel %/fpiar,%1\n\t"
					      "fmovel %/fpcr,%2\n\t"
					      "fmovel %/fpsr,%3"
					      :
					      : "m" (p->thread.fp[0]),
						"m" (p->thread.fpcntl[0]),
						"m" (p->thread.fpcntl[1]),
						"m" (p->thread.fpcntl[2])
					      : "memory");
			} else {
				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]));
	}
#endif /* CONFIG_FPU */

	return 0;
}

/* Fill in the fpu structure for a core dump.  */
#ifdef CONFIG_FPU
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;

	if (CPU_IS_COLDFIRE) {
		asm volatile ("fmovel %/fpiar,%0\n\t"
			      "fmovel %/fpcr,%1\n\t"
			      "fmovel %/fpsr,%2\n\t"
			      "fmovemd %/fp0-%/fp7,%3"
			      :
			      : "m" (fpu->fpcntl[0]),
				"m" (fpu->fpcntl[1]),
				"m" (fpu->fpcntl[2]),
				"m" (fpu->fpregs[0])
			      : "memory");
	} else {
		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);
#endif /* CONFIG_FPU */

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;
}