summaryrefslogtreecommitdiffstats
path: root/arch/sh/kernel/process.c
blob: a7810c9144dc4191b8a8bf95d6467859f37aea4c (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
/* $Id: process.c,v 1.33 2000/03/25 00:06:15 gniibe Exp $
 *
 *  linux/arch/sh/kernel/process.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
 */

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

#define __KERNEL_SYSCALLS__
#include <stdarg.h>

#include <linux/config.h>

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/interrupt.h>
#include <linux/unistd.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/irq.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
#include <asm/elf.h>
#ifdef CONFIG_SH_STANDARD_BIOS
#include <asm/sh_bios.h>
#endif

static int hlt_counter=0;

#define HARD_IDLE_TIMEOUT (HZ / 3)

void disable_hlt(void)
{
	hlt_counter++;
}

void enable_hlt(void)
{
	hlt_counter--;
}

/*
 * The idle loop on a uniprocessor i386..
 */ 
void cpu_idle(void *unused)
{
	/* endless idle loop with no priority at all */
	init_idle();
	current->nice = 20;
	current->counter = -100;

	while (1) {
		while (!current->need_resched) {
			if (hlt_counter)
				continue;
			__sti();
			asm volatile("sleep" : : : "memory");
		}
		schedule();
		check_pgt_cache();
	}
}

void machine_restart(char * __unused)
{
#ifdef CONFIG_SH_STANDARD_BIOS
	sh_bios_shutdown(1);
#endif
}

void machine_halt(void)
{
#ifdef CONFIG_SH_STANDARD_BIOS
	sh_bios_shutdown(0);
#endif
}

void machine_power_off(void)
{
}

void show_regs(struct pt_regs * regs)
{
	printk("\n");
	printk("PC  : %08lx SP  : %08lx SR  : %08lx TEA : %08x\n",
	       regs->pc, regs->regs[15], regs->sr, ctrl_inl(MMU_TEA));
	printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
	       regs->regs[0],regs->regs[1],
	       regs->regs[2],regs->regs[3]);
	printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
	       regs->regs[4],regs->regs[5],
	       regs->regs[6],regs->regs[7]);
	printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
	       regs->regs[8],regs->regs[9],
	       regs->regs[10],regs->regs[11]);
	printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
	       regs->regs[12],regs->regs[13],
	       regs->regs[14]);
	printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
	       regs->mach, regs->macl, regs->gbr, regs->pr);
}

struct task_struct * alloc_task_struct(void)
{
	/* Get two pages */
	return (struct task_struct *) __get_free_pages(GFP_KERNEL,1);
}

void free_task_struct(struct task_struct *p)
{
	free_pages((unsigned long) p, 1);
}

/*
 * Create a kernel thread
 */

/*
 * This is the mechanism for creating a new kernel thread.
 *
 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 * who haven't done an "execve()") should use this: it will work within
 * a system call from a "real" process, but the process memory space will
 * not be free'd until both the parent and the child have exited.
 */
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{	/* Don't use this in BL=1(cli).  Or else, CPU resets! */
	register unsigned long __sc0 __asm__ ("r0");
	register unsigned long __sc3 __asm__ ("r3") = __NR_clone;
	register unsigned long __sc4 __asm__ ("r4") = (long) flags | CLONE_VM;
	register unsigned long __sc5 __asm__ ("r5") = 0;
	register unsigned long __sc8 __asm__ ("r8") = (long) arg;
	register unsigned long __sc9 __asm__ ("r9") = (long) fn;

	__asm__("trapa	#0x12\n\t" 	/* Linux/SH system call */
		"tst	#0xff, r0\n\t"	/* child or parent? */
		"bf	1f\n\t"		/* parent - jump */
		"jsr	@r9\n\t"	/* call fn */
		" mov	r8, r4\n\t"	/* push argument */
		"mov	r0, r4\n\t"	/* return value to arg of exit */
		"mov	%1, r3\n\t"	/* exit */
		"trapa	#0x11\n"
		"1:"
		: "=z" (__sc0)
		: "i" (__NR_exit), "r" (__sc3), "r" (__sc4), "r" (__sc5), 
		  "r" (__sc8), "r" (__sc9)
		: "memory", "t");
	return __sc0;
}

/*
 * Free current thread data structures etc..
 */
void exit_thread(void)
{
	/* Nothing to do. */
}

void flush_thread(void)
{
#if defined(__sh3__)
	/* do nothing */
	/* Possibly, set clear debug registers */
#elif defined(__SH4__)
	struct task_struct *tsk = current;

	/* Forget lazy FPU state */
	clear_fpu(tsk);
	tsk->used_math = 0;
#endif
}

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

/* Fill in the fpu structure for a core dump.. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
#if defined(__SH4__)
	int fpvalid;
	struct task_struct *tsk = current;

	fpvalid = tsk->used_math;
	if (fpvalid) {
		unsigned long flags;

		save_and_cli(flags);
		unlazy_fpu(tsk);
		restore_flags(flags);
		memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
	}

	return fpvalid;
#else
	return 0; /* Task didn't use the fpu at all. */
#endif
}

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;
#if defined(__SH4__)
	struct task_struct *tsk = current;

	if (tsk != &init_task) {
		unsigned long flags;

		save_and_cli(flags);
		unlazy_fpu(tsk);
		restore_flags(flags);
		p->thread.fpu = current->thread.fpu;
		p->used_math = tsk->used_math;
	}
#endif
	childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long) p)) - 1;
	*childregs = *regs;

	if (user_mode(regs)) {
		childregs->regs[15] = usp;
	} else {
		childregs->regs[15] = (unsigned long)p+2*PAGE_SIZE;
	}
	childregs->regs[0] = 0; /* Set return value for child */
	childregs->sr |= SR_FD; /* Invalidate FPU flag */

	p->thread.sp = (unsigned long) childregs;
	p->thread.pc = (unsigned long) ret_from_fork;

	return 0;
}

/*
 * fill in the user structure for a core dump..
 */
void dump_thread(struct pt_regs * regs, struct user * dump)
{
	dump->magic = CMAGIC;
	dump->start_code = current->mm->start_code;
	dump->start_data  = current->mm->start_data;
	dump->start_stack = regs->regs[15] & ~(PAGE_SIZE - 1);
	dump->u_tsize = (current->mm->end_code - dump->start_code) >> PAGE_SHIFT;
	dump->u_dsize = (current->mm->brk + (PAGE_SIZE-1) - dump->start_data) >> PAGE_SHIFT;
	dump->u_ssize = (current->mm->start_stack - dump->start_stack +
			 PAGE_SIZE - 1) >> PAGE_SHIFT;
	/* Debug registers will come here. */

	dump->regs = *regs;

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

/*
 *	switch_to(x,y) should switch tasks from x to y.
 *
 */
void __switch_to(struct task_struct *prev, struct task_struct *next)
{
#if defined(__SH4__)
	if (prev != &init_task) {
		unsigned long flags;

		save_and_cli(flags);
		unlazy_fpu(prev);
		restore_flags(flags);
	}
#endif
	/*
	 * Restore the kernel mode register
	 *   	k7 (r7_bank1)
	 */
	asm volatile("ldc	%0, r7_bank"
		     : /* no output */
		     :"r" (next));
}

asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
			unsigned long r6, unsigned long r7,
			struct pt_regs regs)
{
	return do_fork(SIGCHLD, regs.regs[15], &regs, 0);
}

asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
			 unsigned long r6, unsigned long r7,
			 struct pt_regs regs)
{
	if (!newsp)
		newsp = regs.regs[15];
	return do_fork(clone_flags, newsp, &regs, 0);
}

/*
 * This is trivial, and on the face of it looks like it
 * could equally well be done in user mode.
 *
 * Not so, for quite unobvious reasons - register pressure.
 * In user mode vfork() cannot have a stack frame, and if
 * done by calling the "clone()" system call directly, you
 * do not have enough call-clobbered registers to hold all
 * the information you need.
 */
asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
			 unsigned long r6, unsigned long r7,
			 struct pt_regs regs)
{
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.regs[15], &regs, 0);
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(char *ufilename, char **uargv,
			  char **uenvp, unsigned long r7,
			  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;
}

/*
 * These bracket the sleeping functions..
 */
extern void scheduling_functions_start_here(void);
extern void scheduling_functions_end_here(void);
#define first_sched	((unsigned long) scheduling_functions_start_here)
#define last_sched	((unsigned long) scheduling_functions_end_here)

unsigned long get_wchan(struct task_struct *p)
{
	unsigned long schedule_frame;
	unsigned long pc;

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

	/*
	 * The same comment as on the Alpha applies here, too ...
	 */
	pc = thread_saved_pc(&p->thread);
	if (pc >= (unsigned long) interruptible_sleep_on && pc < (unsigned long) add_timer) {
		schedule_frame = ((unsigned long *)(long)p->thread.sp)[1];
		return (unsigned long)((unsigned long *)schedule_frame)[1];
	}
	return pc;
}

asmlinkage void print_syscall(int x)
{
	unsigned long flags, sr;
	asm("stc	sr, %0": "=r" (sr));
	save_and_cli(flags);
	printk("%c: %c %c, %c: SYSCALL\n", (x&63)+32,
	       (current->flags&PF_USEDFPU)?'C':' ',
	       (init_task.flags&PF_USEDFPU)?'K':' ', (sr&SR_FD)?' ':'F');
	restore_flags(flags);
}

asmlinkage void break_point_trap(unsigned long r4, unsigned long r5,
				 unsigned long r6, unsigned long r7,
				 struct pt_regs regs)
{
	/* Clear tracing.  */
	ctrl_outw(0, UBC_BBRA);
	ctrl_outw(0, UBC_BBRB);

	force_sig(SIGTRAP, current);
}

asmlinkage void break_point_trap_software(unsigned long r4, unsigned long r5,
					  unsigned long r6, unsigned long r7,
					  struct pt_regs regs)
{
	regs.pc -= 2;
	force_sig(SIGTRAP, current);
}