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
36 #include <asm/traps.h>
37 #include <asm/machdep.h>
38 #include <asm/setup.h>
39
40
41 asmlinkage void ret_from_fork(void);
42 asmlinkage void ret_from_kernel_thread(void);
43
arch_cpu_idle(void)44 void arch_cpu_idle(void)
45 {
46 #if defined(MACH_ATARI_ONLY)
47 /* block out HSYNC on the atari (falcon) */
48 __asm__("stop #0x2200" : : : "cc");
49 #else
50 __asm__("stop #0x2000" : : : "cc");
51 #endif
52 }
53
machine_restart(char * __unused)54 void machine_restart(char * __unused)
55 {
56 if (mach_reset)
57 mach_reset();
58 for (;;);
59 }
60
machine_halt(void)61 void machine_halt(void)
62 {
63 if (mach_halt)
64 mach_halt();
65 for (;;);
66 }
67
machine_power_off(void)68 void machine_power_off(void)
69 {
70 do_kernel_power_off();
71 for (;;);
72 }
73
74 void (*pm_power_off)(void);
75 EXPORT_SYMBOL(pm_power_off);
76
show_regs(struct pt_regs * regs)77 void show_regs(struct pt_regs * regs)
78 {
79 pr_info("Format %02x Vector: %04x PC: %08lx Status: %04x %s\n",
80 regs->format, regs->vector, regs->pc, regs->sr,
81 print_tainted());
82 pr_info("ORIG_D0: %08lx D0: %08lx A2: %08lx A1: %08lx\n",
83 regs->orig_d0, regs->d0, regs->a2, regs->a1);
84 pr_info("A0: %08lx D5: %08lx D4: %08lx\n", regs->a0, regs->d5,
85 regs->d4);
86 pr_info("D3: %08lx D2: %08lx D1: %08lx\n", regs->d3, regs->d2,
87 regs->d1);
88 if (!(regs->sr & PS_S))
89 pr_info("USP: %08lx\n", rdusp());
90 }
91
flush_thread(void)92 void flush_thread(void)
93 {
94 current->thread.fc = USER_DATA;
95 #ifdef CONFIG_FPU
96 if (!FPU_IS_EMU) {
97 unsigned long zero = 0;
98 asm volatile("frestore %0": :"m" (zero));
99 }
100 #endif
101 }
102
103 /*
104 * Why not generic sys_clone, you ask? m68k passes all arguments on stack.
105 * And we need all registers saved, which means a bunch of stuff pushed
106 * on top of pt_regs, which means that sys_clone() arguments would be
107 * buried. We could, of course, copy them, but it's too costly for no
108 * good reason - generic clone() would have to copy them *again* for
109 * kernel_clone() anyway. So in this case it's actually better to pass pt_regs *
110 * and extract arguments for kernel_clone() from there. Eventually we might
111 * go for calling kernel_clone() directly from the wrapper, but only after we
112 * are finished with kernel_clone() prototype conversion.
113 */
m68k_clone(struct pt_regs * regs)114 asmlinkage int m68k_clone(struct pt_regs *regs)
115 {
116 /* regs will be equal to current_pt_regs() */
117 struct kernel_clone_args args = {
118 .flags = regs->d1 & ~CSIGNAL,
119 .pidfd = (int __user *)regs->d3,
120 .child_tid = (int __user *)regs->d4,
121 .parent_tid = (int __user *)regs->d3,
122 .exit_signal = regs->d1 & CSIGNAL,
123 .stack = regs->d2,
124 .tls = regs->d5,
125 };
126
127 return kernel_clone(&args);
128 }
129
130 /*
131 * Because extra registers are saved on the stack after the sys_clone3()
132 * arguments, this C wrapper extracts them from pt_regs * and then calls the
133 * generic sys_clone3() implementation.
134 */
m68k_clone3(struct pt_regs * regs)135 asmlinkage int m68k_clone3(struct pt_regs *regs)
136 {
137 return sys_clone3((struct clone_args __user *)regs->d1, regs->d2);
138 }
139
copy_thread(struct task_struct * p,const struct kernel_clone_args * args)140 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
141 {
142 unsigned long clone_flags = args->flags;
143 unsigned long usp = args->stack;
144 unsigned long tls = args->tls;
145 struct fork_frame {
146 struct switch_stack sw;
147 struct pt_regs regs;
148 } *frame;
149
150 frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
151
152 p->thread.ksp = (unsigned long)frame;
153 p->thread.esp0 = (unsigned long)&frame->regs;
154
155 /*
156 * Must save the current SFC/DFC value, NOT the value when
157 * the parent was last descheduled - RGH 10-08-96
158 */
159 p->thread.fc = USER_DATA;
160
161 if (unlikely(args->fn)) {
162 /* kernel thread */
163 memset(frame, 0, sizeof(struct fork_frame));
164 frame->regs.sr = PS_S;
165 frame->sw.a3 = (unsigned long)args->fn;
166 frame->sw.d7 = (unsigned long)args->fn_arg;
167 frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
168 p->thread.usp = 0;
169 return 0;
170 }
171 memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
172 sizeof(struct fork_frame));
173 frame->regs.d0 = 0;
174 frame->sw.retpc = (unsigned long)ret_from_fork;
175 p->thread.usp = usp ?: rdusp();
176
177 if (clone_flags & CLONE_SETTLS)
178 task_thread_info(p)->tp_value = tls;
179
180 #ifdef CONFIG_FPU
181 if (!FPU_IS_EMU) {
182 /* Copy the current fpu state */
183 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
184
185 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
186 if (CPU_IS_COLDFIRE) {
187 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
188 "fmovel %/fpiar,%1\n\t"
189 "fmovel %/fpcr,%2\n\t"
190 "fmovel %/fpsr,%3"
191 :
192 : "m" (p->thread.fp[0]),
193 "m" (p->thread.fpcntl[0]),
194 "m" (p->thread.fpcntl[1]),
195 "m" (p->thread.fpcntl[2])
196 : "memory");
197 } else {
198 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
199 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
200 :
201 : "m" (p->thread.fp[0]),
202 "m" (p->thread.fpcntl[0])
203 : "memory");
204 }
205 }
206
207 /* Restore the state in case the fpu was busy */
208 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
209 }
210 #endif /* CONFIG_FPU */
211
212 return 0;
213 }
214
215 /* Fill in the fpu structure for a core dump. */
dump_fpu(struct pt_regs * regs,struct user_m68kfp_struct * fpu)216 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
217 {
218 if (FPU_IS_EMU) {
219 int i;
220
221 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
222 memcpy(fpu->fpregs, current->thread.fp, 96);
223 /* Convert internal fpu reg representation
224 * into long double format
225 */
226 for (i = 0; i < 24; i += 3)
227 fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
228 ((fpu->fpregs[i] & 0x0000ffff) << 16);
229 return 1;
230 }
231
232 if (IS_ENABLED(CONFIG_FPU)) {
233 char fpustate[216];
234
235 /* First dump the fpu context to avoid protocol violation. */
236 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
237 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
238 return 0;
239
240 if (CPU_IS_COLDFIRE) {
241 asm volatile ("fmovel %/fpiar,%0\n\t"
242 "fmovel %/fpcr,%1\n\t"
243 "fmovel %/fpsr,%2\n\t"
244 "fmovemd %/fp0-%/fp7,%3"
245 :
246 : "m" (fpu->fpcntl[0]),
247 "m" (fpu->fpcntl[1]),
248 "m" (fpu->fpcntl[2]),
249 "m" (fpu->fpregs[0])
250 : "memory");
251 } else {
252 asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
253 :
254 : "m" (fpu->fpcntl[0])
255 : "memory");
256 asm volatile ("fmovemx %/fp0-%/fp7,%0"
257 :
258 : "m" (fpu->fpregs[0])
259 : "memory");
260 }
261 }
262
263 return 1;
264 }
265 EXPORT_SYMBOL(dump_fpu);
266
__get_wchan(struct task_struct * p)267 unsigned long __get_wchan(struct task_struct *p)
268 {
269 unsigned long fp, pc;
270 unsigned long stack_page;
271 int count = 0;
272
273 stack_page = (unsigned long)task_stack_page(p);
274 fp = ((struct switch_stack *)p->thread.ksp)->a6;
275 do {
276 if (fp < stack_page+sizeof(struct thread_info) ||
277 fp >= 8184+stack_page)
278 return 0;
279 pc = ((unsigned long *)fp)[1];
280 if (!in_sched_functions(pc))
281 return pc;
282 fp = *(unsigned long *) fp;
283 } while (count++ < 16);
284 return 0;
285 }
286