1/*
  2 *  linux/arch/m68k/kernel/process.c
  3 *
  4 *  Copyright (C) 1995  Hamish Macdonald
  5 *
  6 *  68060 fixes by Jesper Skov
  7 */
  8
  9/*
 10 * This file handles the architecture-dependent parts of process handling..
 11 */
 12
 13#include <linux/errno.h>
 14#include <linux/module.h>
 15#include <linux/sched.h>
 16#include <linux/kernel.h>
 17#include <linux/mm.h>
 18#include <linux/slab.h>
 19#include <linux/fs.h>
 20#include <linux/smp.h>
 21#include <linux/stddef.h>
 22#include <linux/unistd.h>
 23#include <linux/ptrace.h>
 24#include <linux/user.h>
 25#include <linux/reboot.h>
 26#include <linux/init_task.h>
 27#include <linux/mqueue.h>
 28
 29#include <asm/uaccess.h>
 30#include <asm/system.h>
 31#include <asm/traps.h>
 32#include <asm/machdep.h>
 33#include <asm/setup.h>
 34#include <asm/pgtable.h>
 35
 36/*
 37 * Initial task/thread structure. Make this a per-architecture thing,
 38 * because different architectures tend to have different
 39 * alignment requirements and potentially different initial
 40 * setup.
 41 */
 42static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
 43static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
 44union thread_union init_thread_union __init_task_data
 45	__attribute__((aligned(THREAD_SIZE))) =
 46		{ INIT_THREAD_INFO(init_task) };
 47
 48/* initial task structure */
 49struct task_struct init_task = INIT_TASK(init_task);
 50
 51EXPORT_SYMBOL(init_task);
 52
 53asmlinkage void ret_from_fork(void);
 54
 55
 56/*
 57 * Return saved PC from a blocked thread
 58 */
 59unsigned long thread_saved_pc(struct task_struct *tsk)
 60{
 61	struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
 62	/* Check whether the thread is blocked in resume() */
 63	if (in_sched_functions(sw->retpc))
 64		return ((unsigned long *)sw->a6)[1];
 65	else
 66		return sw->retpc;
 67}
 68
 69/*
 70 * The idle loop on an m68k..
 71 */
 72static void default_idle(void)
 73{
 74	if (!need_resched())
 75#if defined(MACH_ATARI_ONLY)
 76		/* block out HSYNC on the atari (falcon) */
 77		__asm__("stop #0x2200" : : : "cc");
 78#else
 79		__asm__("stop #0x2000" : : : "cc");
 80#endif
 81}
 82
 83void (*idle)(void) = default_idle;
 84
 85/*
 86 * The idle thread. There's no useful work to be
 87 * done, so just try to conserve power and have a
 88 * low exit latency (ie sit in a loop waiting for
 89 * somebody to say that they'd like to reschedule)
 90 */
 91void cpu_idle(void)
 92{
 93	/* endless idle loop with no priority at all */
 94	while (1) {
 95		while (!need_resched())
 96			idle();
 97		preempt_enable_no_resched();
 98		schedule();
 99		preempt_disable();
100	}
101}
102
103void machine_restart(char * __unused)
104{
105	if (mach_reset)
106		mach_reset();
107	for (;;);
108}
109
110void machine_halt(void)
111{
112	if (mach_halt)
113		mach_halt();
114	for (;;);
115}
116
117void machine_power_off(void)
118{
119	if (mach_power_off)
120		mach_power_off();
121	for (;;);
122}
123
124void (*pm_power_off)(void) = machine_power_off;
125EXPORT_SYMBOL(pm_power_off);
126
127void show_regs(struct pt_regs * regs)
128{
129	printk("\n");
130	printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
131	       regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
132	printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
133	       regs->orig_d0, regs->d0, regs->a2, regs->a1);
134	printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
135	       regs->a0, regs->d5, regs->d4);
136	printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
137	       regs->d3, regs->d2, regs->d1);
138	if (!(regs->sr & PS_S))
139		printk("USP: %08lx\n", rdusp());
140}
141
142/*
143 * Create a kernel thread
144 */
145int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
146{
147	int pid;
148	mm_segment_t fs;
149
150	fs = get_fs();
151	set_fs (KERNEL_DS);
152
153	{
154	register long retval __asm__ ("d0");
155	register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
156
157	retval = __NR_clone;
158	__asm__ __volatile__
159	  ("clrl %%d2\n\t"
160	   "trap #0\n\t"		/* Linux/m68k system call */
161	   "tstl %0\n\t"		/* child or parent */
162	   "jne 1f\n\t"			/* parent - jump */
163	   "lea %%sp@(%c7),%6\n\t"	/* reload current */
164	   "movel %6@,%6\n\t"
165	   "movel %3,%%sp@-\n\t"	/* push argument */
166	   "jsr %4@\n\t"		/* call fn */
167	   "movel %0,%%d1\n\t"		/* pass exit value */
168	   "movel %2,%%d0\n\t"		/* exit */
169	   "trap #0\n"
170	   "1:"
171	   : "+d" (retval)
172	   : "i" (__NR_clone), "i" (__NR_exit),
173	     "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
174	     "i" (-THREAD_SIZE)
175	   : "d2");
176
177	pid = retval;
178	}
179
180	set_fs (fs);
181	return pid;
182}
183EXPORT_SYMBOL(kernel_thread);
184
185void flush_thread(void)
186{
187	unsigned long zero = 0;
188
189	current->thread.fs = __USER_DS;
190	if (!FPU_IS_EMU)
191		asm volatile (".chip 68k/68881\n\t"
192			      "frestore %0@\n\t"
193			      ".chip 68k" : : "a" (&zero));
194}
195
196/*
197 * "m68k_fork()".. By the time we get here, the
198 * non-volatile registers have also been saved on the
199 * stack. We do some ugly pointer stuff here.. (see
200 * also copy_thread)
201 */
202
203asmlinkage int m68k_fork(struct pt_regs *regs)
204{
205	return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
206}
207
208asmlinkage int m68k_vfork(struct pt_regs *regs)
209{
210	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
211		       NULL, NULL);
212}
213
214asmlinkage int m68k_clone(struct pt_regs *regs)
215{
216	unsigned long clone_flags;
217	unsigned long newsp;
218	int __user *parent_tidptr, *child_tidptr;
219
220	/* syscall2 puts clone_flags in d1 and usp in d2 */
221	clone_flags = regs->d1;
222	newsp = regs->d2;
223	parent_tidptr = (int __user *)regs->d3;
224	child_tidptr = (int __user *)regs->d4;
225	if (!newsp)
226		newsp = rdusp();
227	return do_fork(clone_flags, newsp, regs, 0,
228		       parent_tidptr, child_tidptr);
229}
230
231int copy_thread(unsigned long clone_flags, unsigned long usp,
232		 unsigned long unused,
233		 struct task_struct * p, struct pt_regs * regs)
234{
235	struct pt_regs * childregs;
236	struct switch_stack * childstack, *stack;
237	unsigned long *retp;
238
239	childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
240
241	*childregs = *regs;
242	childregs->d0 = 0;
243
244	retp = ((unsigned long *) regs);
245	stack = ((struct switch_stack *) retp) - 1;
246
247	childstack = ((struct switch_stack *) childregs) - 1;
248	*childstack = *stack;
249	childstack->retpc = (unsigned long)ret_from_fork;
250
251	p->thread.usp = usp;
252	p->thread.ksp = (unsigned long)childstack;
253
254	if (clone_flags & CLONE_SETTLS)
255		task_thread_info(p)->tp_value = regs->d5;
256
257	/*
258	 * Must save the current SFC/DFC value, NOT the value when
259	 * the parent was last descheduled - RGH  10-08-96
260	 */
261	p->thread.fs = get_fs().seg;
262
263	if (!FPU_IS_EMU) {
264		/* Copy the current fpu state */
265		asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
266
267		if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2])
268		  asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
269				"fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
270				: : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
271				: "memory");
272		/* Restore the state in case the fpu was busy */
273		asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
274	}
275
276	return 0;
277}
278
279/* Fill in the fpu structure for a core dump.  */
280
281int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
282{
283	char fpustate[216];
284
285	if (FPU_IS_EMU) {
286		int i;
287
288		memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
289		memcpy(fpu->fpregs, current->thread.fp, 96);
290		/* Convert internal fpu reg representation
291		 * into long double format
292		 */
293		for (i = 0; i < 24; i += 3)
294			fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
295			                 ((fpu->fpregs[i] & 0x0000ffff) << 16);
296		return 1;
297	}
298
299	/* First dump the fpu context to avoid protocol violation.  */
300	asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
301	if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
302		return 0;
303
304	asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
305		:: "m" (fpu->fpcntl[0])
306		: "memory");
307	asm volatile ("fmovemx %/fp0-%/fp7,%0"
308		:: "m" (fpu->fpregs[0])
309		: "memory");
310	return 1;
311}
312EXPORT_SYMBOL(dump_fpu);
313
314/*
315 * sys_execve() executes a new program.
316 */
317asmlinkage int sys_execve(const char __user *name,
318			  const char __user *const __user *argv,
319			  const char __user *const __user *envp)
320{
321	int error;
322	char * filename;
323	struct pt_regs *regs = (struct pt_regs *) &name;
324
325	filename = getname(name);
326	error = PTR_ERR(filename);
327	if (IS_ERR(filename))
328		return error;
329	error = do_execve(filename, argv, envp, regs);
330	putname(filename);
331	return error;
332}
333
334unsigned long get_wchan(struct task_struct *p)
335{
336	unsigned long fp, pc;
337	unsigned long stack_page;
338	int count = 0;
339	if (!p || p == current || p->state == TASK_RUNNING)
340		return 0;
341
342	stack_page = (unsigned long)task_stack_page(p);
343	fp = ((struct switch_stack *)p->thread.ksp)->a6;
344	do {
345		if (fp < stack_page+sizeof(struct thread_info) ||
346		    fp >= 8184+stack_page)
347			return 0;
348		pc = ((unsigned long *)fp)[1];
349		if (!in_sched_functions(pc))
350			return pc;
351		fp = *(unsigned long *) fp;
352	} while (count++ < 16);
353	return 0;
354}