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#include <linux/rcupdate.h>
29
30#include <asm/uaccess.h>
31#include <asm/traps.h>
32#include <asm/machdep.h>
33#include <asm/setup.h>
34#include <asm/pgtable.h>
35
36
37asmlinkage void ret_from_fork(void);
38asmlinkage void ret_from_kernel_thread(void);
39
40
41/*
42 * Return saved PC from a blocked thread
43 */
44unsigned long thread_saved_pc(struct task_struct *tsk)
45{
46	struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
47	/* Check whether the thread is blocked in resume() */
48	if (in_sched_functions(sw->retpc))
49		return ((unsigned long *)sw->a6)[1];
50	else
51		return sw->retpc;
52}
53
54void arch_cpu_idle(void)
55{
56#if defined(MACH_ATARI_ONLY)
57	/* block out HSYNC on the atari (falcon) */
58	__asm__("stop #0x2200" : : : "cc");
59#else
60	__asm__("stop #0x2000" : : : "cc");
61#endif
62}
63
64void machine_restart(char * __unused)
65{
66	if (mach_reset)
67		mach_reset();
68	for (;;);
69}
70
71void machine_halt(void)
72{
73	if (mach_halt)
74		mach_halt();
75	for (;;);
76}
77
78void machine_power_off(void)
79{
80	if (mach_power_off)
81		mach_power_off();
82	for (;;);
83}
84
85void (*pm_power_off)(void) = machine_power_off;
86EXPORT_SYMBOL(pm_power_off);
87
88void show_regs(struct pt_regs * regs)
89{
90	printk("\n");
91	printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
92	       regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
93	printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
94	       regs->orig_d0, regs->d0, regs->a2, regs->a1);
95	printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
96	       regs->a0, regs->d5, regs->d4);
97	printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
98	       regs->d3, regs->d2, regs->d1);
99	if (!(regs->sr & PS_S))
100		printk("USP: %08lx\n", rdusp());
101}
102
103void flush_thread(void)
104{
105	current->thread.fs = __USER_DS;
106#ifdef CONFIG_FPU
107	if (!FPU_IS_EMU) {
108		unsigned long zero = 0;
109		asm volatile("frestore %0": :"m" (zero));
110	}
111#endif
112}
113
114/*
115 * Why not generic sys_clone, you ask?  m68k passes all arguments on stack.
116 * And we need all registers saved, which means a bunch of stuff pushed
117 * on top of pt_regs, which means that sys_clone() arguments would be
118 * buried.  We could, of course, copy them, but it's too costly for no
119 * good reason - generic clone() would have to copy them *again* for
120 * do_fork() anyway.  So in this case it's actually better to pass pt_regs *
121 * and extract arguments for do_fork() from there.  Eventually we might
122 * go for calling do_fork() directly from the wrapper, but only after we
123 * are finished with do_fork() prototype conversion.
124 */
125asmlinkage int m68k_clone(struct pt_regs *regs)
126{
127	/* regs will be equal to current_pt_regs() */
128	return do_fork(regs->d1, regs->d2, 0,
129		       (int __user *)regs->d3, (int __user *)regs->d4);
130}
131
132int copy_thread(unsigned long clone_flags, unsigned long usp,
133		 unsigned long arg, struct task_struct *p)
134{
135	struct fork_frame {
136		struct switch_stack sw;
137		struct pt_regs regs;
138	} *frame;
139
140	frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
141
142	p->thread.ksp = (unsigned long)frame;
143	p->thread.esp0 = (unsigned long)&frame->regs;
144
145	/*
146	 * Must save the current SFC/DFC value, NOT the value when
147	 * the parent was last descheduled - RGH  10-08-96
148	 */
149	p->thread.fs = get_fs().seg;
150
151	if (unlikely(p->flags & PF_KTHREAD)) {
152		/* kernel thread */
153		memset(frame, 0, sizeof(struct fork_frame));
154		frame->regs.sr = PS_S;
155		frame->sw.a3 = usp; /* function */
156		frame->sw.d7 = arg;
157		frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
158		p->thread.usp = 0;
159		return 0;
160	}
161	memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
162		sizeof(struct fork_frame));
163	frame->regs.d0 = 0;
164	frame->sw.retpc = (unsigned long)ret_from_fork;
165	p->thread.usp = usp ?: rdusp();
166
167	if (clone_flags & CLONE_SETTLS)
168		task_thread_info(p)->tp_value = frame->regs.d5;
169
170#ifdef CONFIG_FPU
171	if (!FPU_IS_EMU) {
172		/* Copy the current fpu state */
173		asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
174
175		if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
176			if (CPU_IS_COLDFIRE) {
177				asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
178					      "fmovel %/fpiar,%1\n\t"
179					      "fmovel %/fpcr,%2\n\t"
180					      "fmovel %/fpsr,%3"
181					      :
182					      : "m" (p->thread.fp[0]),
183						"m" (p->thread.fpcntl[0]),
184						"m" (p->thread.fpcntl[1]),
185						"m" (p->thread.fpcntl[2])
186					      : "memory");
187			} else {
188				asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
189					      "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
190					      :
191					      : "m" (p->thread.fp[0]),
192						"m" (p->thread.fpcntl[0])
193					      : "memory");
194			}
195		}
196
197		/* Restore the state in case the fpu was busy */
198		asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
199	}
200#endif /* CONFIG_FPU */
201
202	return 0;
203}
204
205/* Fill in the fpu structure for a core dump.  */
206#ifdef CONFIG_FPU
207int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
208{
209	char fpustate[216];
210
211	if (FPU_IS_EMU) {
212		int i;
213
214		memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
215		memcpy(fpu->fpregs, current->thread.fp, 96);
216		/* Convert internal fpu reg representation
217		 * into long double format
218		 */
219		for (i = 0; i < 24; i += 3)
220			fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
221			                 ((fpu->fpregs[i] & 0x0000ffff) << 16);
222		return 1;
223	}
224
225	/* First dump the fpu context to avoid protocol violation.  */
226	asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
227	if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
228		return 0;
229
230	if (CPU_IS_COLDFIRE) {
231		asm volatile ("fmovel %/fpiar,%0\n\t"
232			      "fmovel %/fpcr,%1\n\t"
233			      "fmovel %/fpsr,%2\n\t"
234			      "fmovemd %/fp0-%/fp7,%3"
235			      :
236			      : "m" (fpu->fpcntl[0]),
237				"m" (fpu->fpcntl[1]),
238				"m" (fpu->fpcntl[2]),
239				"m" (fpu->fpregs[0])
240			      : "memory");
241	} else {
242		asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
243			      :
244			      : "m" (fpu->fpcntl[0])
245			      : "memory");
246		asm volatile ("fmovemx %/fp0-%/fp7,%0"
247			      :
248			      : "m" (fpu->fpregs[0])
249			      : "memory");
250	}
251
252	return 1;
253}
254EXPORT_SYMBOL(dump_fpu);
255#endif /* CONFIG_FPU */
256
257unsigned long get_wchan(struct task_struct *p)
258{
259	unsigned long fp, pc;
260	unsigned long stack_page;
261	int count = 0;
262	if (!p || p == current || p->state == TASK_RUNNING)
263		return 0;
264
265	stack_page = (unsigned long)task_stack_page(p);
266	fp = ((struct switch_stack *)p->thread.ksp)->a6;
267	do {
268		if (fp < stack_page+sizeof(struct thread_info) ||
269		    fp >= 8184+stack_page)
270			return 0;
271		pc = ((unsigned long *)fp)[1];
272		if (!in_sched_functions(pc))
273			return pc;
274		fp = *(unsigned long *) fp;
275	} while (count++ < 16);
276	return 0;
277}
278