1// SPDX-License-Identifier: GPL-2.0
2/*
3 *  linux/arch/m68k/kernel/process.c
4 *
5 *  Copyright (C) 1995  Hamish Macdonald
6 *
7 *  68060 fixes by Jesper Skov
8 */
9
10/*
11 * This file handles the architecture-dependent parts of process handling..
12 */
13
14#include <linux/errno.h>
15#include <linux/module.h>
16#include <linux/sched.h>
17#include <linux/sched/debug.h>
18#include <linux/sched/task.h>
19#include <linux/sched/task_stack.h>
20#include <linux/kernel.h>
21#include <linux/mm.h>
22#include <linux/slab.h>
23#include <linux/fs.h>
24#include <linux/smp.h>
25#include <linux/stddef.h>
26#include <linux/unistd.h>
27#include <linux/ptrace.h>
28#include <linux/user.h>
29#include <linux/reboot.h>
30#include <linux/init_task.h>
31#include <linux/mqueue.h>
32#include <linux/rcupdate.h>
33#include <linux/syscalls.h>
34#include <linux/uaccess.h>
35#include <linux/elfcore.h>
36
37#include <asm/traps.h>
38#include <asm/machdep.h>
39#include <asm/setup.h>
40
41#include "process.h"
42
43asmlinkage void ret_from_fork(void);
44asmlinkage void ret_from_kernel_thread(void);
45
46void arch_cpu_idle(void)
47{
48#if defined(MACH_ATARI_ONLY)
49	/* block out HSYNC on the atari (falcon) */
50	__asm__("stop #0x2200" : : : "cc");
51#else
52	__asm__("stop #0x2000" : : : "cc");
53#endif
54}
55
56void machine_restart(char * __unused)
57{
58	if (mach_reset)
59		mach_reset();
60	for (;;);
61}
62
63void machine_halt(void)
64{
65	if (mach_halt)
66		mach_halt();
67	for (;;);
68}
69
70void machine_power_off(void)
71{
72	do_kernel_power_off();
73	for (;;);
74}
75
76void (*pm_power_off)(void);
77EXPORT_SYMBOL(pm_power_off);
78
79void show_regs(struct pt_regs * regs)
80{
81	pr_info("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
82		regs->format, regs->vector, regs->pc, regs->sr,
83		print_tainted());
84	pr_info("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
85		regs->orig_d0, regs->d0, regs->a2, regs->a1);
86	pr_info("A0: %08lx  D5: %08lx  D4: %08lx\n", regs->a0, regs->d5,
87		regs->d4);
88	pr_info("D3: %08lx  D2: %08lx  D1: %08lx\n", regs->d3, regs->d2,
89		regs->d1);
90	if (!(regs->sr & PS_S))
91		pr_info("USP: %08lx\n", rdusp());
92}
93
94void flush_thread(void)
95{
96	current->thread.fc = USER_DATA;
97#ifdef CONFIG_FPU
98	if (!FPU_IS_EMU) {
99		unsigned long zero = 0;
100		asm volatile("frestore %0": :"m" (zero));
101	}
102#endif
103}
104
105/*
106 * Why not generic sys_clone, you ask?  m68k passes all arguments on stack.
107 * And we need all registers saved, which means a bunch of stuff pushed
108 * on top of pt_regs, which means that sys_clone() arguments would be
109 * buried.  We could, of course, copy them, but it's too costly for no
110 * good reason - generic clone() would have to copy them *again* for
111 * kernel_clone() anyway.  So in this case it's actually better to pass pt_regs *
112 * and extract arguments for kernel_clone() from there.  Eventually we might
113 * go for calling kernel_clone() directly from the wrapper, but only after we
114 * are finished with kernel_clone() prototype conversion.
115 */
116asmlinkage int m68k_clone(struct pt_regs *regs)
117{
118	/* regs will be equal to current_pt_regs() */
119	struct kernel_clone_args args = {
120		.flags		= regs->d1 & ~CSIGNAL,
121		.pidfd		= (int __user *)regs->d3,
122		.child_tid	= (int __user *)regs->d4,
123		.parent_tid	= (int __user *)regs->d3,
124		.exit_signal	= regs->d1 & CSIGNAL,
125		.stack		= regs->d2,
126		.tls		= regs->d5,
127	};
128
129	return kernel_clone(&args);
130}
131
132/*
133 * Because extra registers are saved on the stack after the sys_clone3()
134 * arguments, this C wrapper extracts them from pt_regs * and then calls the
135 * generic sys_clone3() implementation.
136 */
137asmlinkage int m68k_clone3(struct pt_regs *regs)
138{
139	return sys_clone3((struct clone_args __user *)regs->d1, regs->d2);
140}
141
142int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
143{
144	unsigned long clone_flags = args->flags;
145	unsigned long usp = args->stack;
146	unsigned long tls = args->tls;
147	struct fork_frame {
148		struct switch_stack sw;
149		struct pt_regs regs;
150	} *frame;
151
152	frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
153
154	p->thread.ksp = (unsigned long)frame;
155	p->thread.esp0 = (unsigned long)&frame->regs;
156
157	/*
158	 * Must save the current SFC/DFC value, NOT the value when
159	 * the parent was last descheduled - RGH  10-08-96
160	 */
161	p->thread.fc = USER_DATA;
162
163	if (unlikely(args->fn)) {
164		/* kernel thread */
165		memset(frame, 0, sizeof(struct fork_frame));
166		frame->regs.sr = PS_S;
167		frame->sw.a3 = (unsigned long)args->fn;
168		frame->sw.d7 = (unsigned long)args->fn_arg;
169		frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
170		p->thread.usp = 0;
171		return 0;
172	}
173	memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
174		sizeof(struct fork_frame));
175	frame->regs.d0 = 0;
176	frame->sw.retpc = (unsigned long)ret_from_fork;
177	p->thread.usp = usp ?: rdusp();
178
179	if (clone_flags & CLONE_SETTLS)
180		task_thread_info(p)->tp_value = tls;
181
182#ifdef CONFIG_FPU
183	if (!FPU_IS_EMU) {
184		/* Copy the current fpu state */
185		asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
186
187		if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
188			if (CPU_IS_COLDFIRE) {
189				asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
190					      "fmovel %/fpiar,%1\n\t"
191					      "fmovel %/fpcr,%2\n\t"
192					      "fmovel %/fpsr,%3"
193					      :
194					      : "m" (p->thread.fp[0]),
195						"m" (p->thread.fpcntl[0]),
196						"m" (p->thread.fpcntl[1]),
197						"m" (p->thread.fpcntl[2])
198					      : "memory");
199			} else {
200				asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
201					      "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
202					      :
203					      : "m" (p->thread.fp[0]),
204						"m" (p->thread.fpcntl[0])
205					      : "memory");
206			}
207		}
208
209		/* Restore the state in case the fpu was busy */
210		asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
211	}
212#endif /* CONFIG_FPU */
213
214	return 0;
215}
216
217/* Fill in the fpu structure for a core dump.  */
218int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
219{
220	if (FPU_IS_EMU) {
221		int i;
222
223		memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
224		memcpy(fpu->fpregs, current->thread.fp, 96);
225		/* Convert internal fpu reg representation
226		 * into long double format
227		 */
228		for (i = 0; i < 24; i += 3)
229			fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
230			                 ((fpu->fpregs[i] & 0x0000ffff) << 16);
231		return 1;
232	}
233
234	if (IS_ENABLED(CONFIG_FPU)) {
235		char fpustate[216];
236
237		/* First dump the fpu context to avoid protocol violation.  */
238		asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
239		if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
240			return 0;
241
242		if (CPU_IS_COLDFIRE) {
243			asm volatile ("fmovel %/fpiar,%0\n\t"
244				      "fmovel %/fpcr,%1\n\t"
245				      "fmovel %/fpsr,%2\n\t"
246				      "fmovemd %/fp0-%/fp7,%3"
247				      :
248				      : "m" (fpu->fpcntl[0]),
249					"m" (fpu->fpcntl[1]),
250					"m" (fpu->fpcntl[2]),
251					"m" (fpu->fpregs[0])
252				      : "memory");
253		} else {
254			asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
255				      :
256				      : "m" (fpu->fpcntl[0])
257				      : "memory");
258			asm volatile ("fmovemx %/fp0-%/fp7,%0"
259				      :
260				      : "m" (fpu->fpregs[0])
261				      : "memory");
262		}
263	}
264
265	return 1;
266}
267
268unsigned long __get_wchan(struct task_struct *p)
269{
270	unsigned long fp, pc;
271	unsigned long stack_page;
272	int count = 0;
273
274	stack_page = (unsigned long)task_stack_page(p);
275	fp = ((struct switch_stack *)p->thread.ksp)->a6;
276	do {
277		if (fp < stack_page+sizeof(struct thread_info) ||
278		    fp >= 8184+stack_page)
279			return 0;
280		pc = ((unsigned long *)fp)[1];
281		if (!in_sched_functions(pc))
282			return pc;
283		fp = *(unsigned long *) fp;
284	} while (count++ < 16);
285	return 0;
286}
287