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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 = (u32)(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(kargs: &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 u64 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(task: 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(task: 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(addr: pc))
282 return pc;
283 fp = *(unsigned long *) fp;
284 } while (count++ < 16);
285 return 0;
286}
287

source code of linux/arch/m68k/kernel/process.c