1/*
  2 *  linux/arch/h8300/kernel/process.c
  3 *
  4 * Yoshinori Sato <ysato@users.sourceforge.jp>
  5 *
  6 *  Based on:
  7 *
  8 *  linux/arch/m68knommu/kernel/process.c
  9 *
 10 *  Copyright (C) 1998  D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>,
 11 *                      Kenneth Albanowski <kjahds@kjahds.com>,
 12 *                      The Silver Hammer Group, Ltd.
 13 *
 14 *  linux/arch/m68k/kernel/process.c
 15 *
 16 *  Copyright (C) 1995  Hamish Macdonald
 17 *
 18 *  68060 fixes by Jesper Skov
 19 */
 20
 21/*
 22 * This file handles the architecture-dependent parts of process handling..
 23 */
 24
 25#include <linux/errno.h>
 26#include <linux/module.h>
 27#include <linux/sched.h>
 28#include <linux/kernel.h>
 29#include <linux/mm.h>
 30#include <linux/smp.h>
 31#include <linux/stddef.h>
 32#include <linux/unistd.h>
 33#include <linux/ptrace.h>
 34#include <linux/user.h>
 35#include <linux/interrupt.h>
 36#include <linux/reboot.h>
 37#include <linux/fs.h>
 38#include <linux/slab.h>
 39
 40#include <asm/uaccess.h>
 41#include <asm/traps.h>
 42#include <asm/setup.h>
 43#include <asm/pgtable.h>
 44
 45void (*pm_power_off)(void) = NULL;
 46EXPORT_SYMBOL(pm_power_off);
 47
 48asmlinkage void ret_from_fork(void);
 49
 50/*
 51 * The idle loop on an H8/300..
 52 */
 53#if !defined(CONFIG_H8300H_SIM) && !defined(CONFIG_H8S_SIM)
 54static void default_idle(void)
 55{
 56	local_irq_disable();
 57	if (!need_resched()) {
 58		local_irq_enable();
 59		/* XXX: race here! What if need_resched() gets set now? */
 60		__asm__("sleep");
 61	} else
 62		local_irq_enable();
 63}
 64#else
 65static void default_idle(void)
 66{
 67	cpu_relax();
 68}
 69#endif
 70void (*idle)(void) = default_idle;
 71
 72/*
 73 * The idle thread. There's no useful work to be
 74 * done, so just try to conserve power and have a
 75 * low exit latency (ie sit in a loop waiting for
 76 * somebody to say that they'd like to reschedule)
 77 */
 78void cpu_idle(void)
 79{
 80	while (1) {
 81		while (!need_resched())
 82			idle();
 83		schedule_preempt_disabled();
 84	}
 85}
 86
 87void machine_restart(char * __unused)
 88{
 89	local_irq_disable();
 90	__asm__("jmp @@0"); 
 91}
 92
 93void machine_halt(void)
 94{
 95	local_irq_disable();
 96	__asm__("sleep");
 97	for (;;);
 98}
 99
100void machine_power_off(void)
101{
102	local_irq_disable();
103	__asm__("sleep");
104	for (;;);
105}
106
107void show_regs(struct pt_regs * regs)
108{
109	printk("\nPC: %08lx  Status: %02x",
110	       regs->pc, regs->ccr);
111	printk("\nORIG_ER0: %08lx ER0: %08lx ER1: %08lx",
112	       regs->orig_er0, regs->er0, regs->er1);
113	printk("\nER2: %08lx ER3: %08lx ER4: %08lx ER5: %08lx",
114	       regs->er2, regs->er3, regs->er4, regs->er5);
115	printk("\nER6' %08lx ",regs->er6);
116	if (user_mode(regs))
117		printk("USP: %08lx\n", rdusp());
118	else
119		printk("\n");
120}
121
122/*
123 * Create a kernel thread
124 */
125int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
126{
127	long retval;
128	long clone_arg;
129	mm_segment_t fs;
130
131	fs = get_fs();
132	set_fs (KERNEL_DS);
133	clone_arg = flags | CLONE_VM;
134	__asm__("mov.l sp,er3\n\t"
135		"sub.l er2,er2\n\t"
136		"mov.l %2,er1\n\t"
137		"mov.l %1,er0\n\t"
138		"trapa #0\n\t"
139		"cmp.l sp,er3\n\t"
140		"beq 1f\n\t"
141		"mov.l %4,er0\n\t"
142		"mov.l %3,er1\n\t"
143		"jsr @er1\n\t"
144		"mov.l %5,er0\n\t"
145		"trapa #0\n"
146		"1:\n\t"
147		"mov.l er0,%0"
148		:"=r"(retval)
149		:"i"(__NR_clone),"g"(clone_arg),"g"(fn),"g"(arg),"i"(__NR_exit)
150		:"er0","er1","er2","er3");
151	set_fs (fs);
152	return retval;
153}
154
155void flush_thread(void)
156{
157}
158
159/*
160 * "h8300_fork()".. By the time we get here, the
161 * non-volatile registers have also been saved on the
162 * stack. We do some ugly pointer stuff here.. (see
163 * also copy_thread)
164 */
165
166asmlinkage int h8300_fork(struct pt_regs *regs)
167{
168	return -EINVAL;
169}
170
171asmlinkage int h8300_vfork(struct pt_regs *regs)
172{
173	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
174}
175
176asmlinkage int h8300_clone(struct pt_regs *regs)
177{
178	unsigned long clone_flags;
179	unsigned long newsp;
180
181	/* syscall2 puts clone_flags in er1 and usp in er2 */
182	clone_flags = regs->er1;
183	newsp = regs->er2;
184	if (!newsp)
185		newsp  = rdusp();
186	return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
187
188}
189
190int copy_thread(unsigned long clone_flags,
191                unsigned long usp, unsigned long topstk,
192		 struct task_struct * p, struct pt_regs * regs)
193{
194	struct pt_regs * childregs;
195
196	childregs = (struct pt_regs *) (THREAD_SIZE + task_stack_page(p)) - 1;
197
198	*childregs = *regs;
199	childregs->retpc = (unsigned long) ret_from_fork;
200	childregs->er0 = 0;
201
202	p->thread.usp = usp;
203	p->thread.ksp = (unsigned long)childregs;
204
205	return 0;
206}
207
208/*
209 * sys_execve() executes a new program.
210 */
211asmlinkage int sys_execve(const char *name,
212			  const char *const *argv,
213			  const char *const *envp,
214			  int dummy, ...)
215{
216	int error;
217	char * filename;
218	struct pt_regs *regs = (struct pt_regs *) ((unsigned char *)&dummy-4);
219
220	filename = getname(name);
221	error = PTR_ERR(filename);
222	if (IS_ERR(filename))
223		return error;
224	error = do_execve(filename, argv, envp, regs);
225	putname(filename);
226	return error;
227}
228
229unsigned long thread_saved_pc(struct task_struct *tsk)
230{
231	return ((struct pt_regs *)tsk->thread.esp0)->pc;
232}
233
234unsigned long get_wchan(struct task_struct *p)
235{
236	unsigned long fp, pc;
237	unsigned long stack_page;
238	int count = 0;
239	if (!p || p == current || p->state == TASK_RUNNING)
240		return 0;
241
242	stack_page = (unsigned long)p;
243	fp = ((struct pt_regs *)p->thread.ksp)->er6;
244	do {
245		if (fp < stack_page+sizeof(struct thread_info) ||
246		    fp >= 8184+stack_page)
247			return 0;
248		pc = ((unsigned long *)fp)[1];
249		if (!in_sched_functions(pc))
250			return pc;
251		fp = *(unsigned long *) fp;
252	} while (count++ < 16);
253	return 0;
254}