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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * OpenRISC process.c
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
12 *
13 * This file handles the architecture-dependent parts of process handling...
14 */
15
16#define __KERNEL_SYSCALLS__
17#include <linux/errno.h>
18#include <linux/sched.h>
19#include <linux/sched/debug.h>
20#include <linux/sched/task.h>
21#include <linux/sched/task_stack.h>
22#include <linux/kernel.h>
23#include <linux/export.h>
24#include <linux/mm.h>
25#include <linux/stddef.h>
26#include <linux/unistd.h>
27#include <linux/ptrace.h>
28#include <linux/slab.h>
29#include <linux/elfcore.h>
30#include <linux/interrupt.h>
31#include <linux/delay.h>
32#include <linux/init_task.h>
33#include <linux/mqueue.h>
34#include <linux/fs.h>
35#include <linux/reboot.h>
36
37#include <linux/uaccess.h>
38#include <asm/io.h>
39#include <asm/processor.h>
40#include <asm/spr_defs.h>
41
42#include <linux/smp.h>
43
44/*
45 * Pointer to Current thread info structure.
46 *
47 * Used at user space -> kernel transitions.
48 */
49struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
50
51void machine_restart(char *cmd)
52{
53 do_kernel_restart(cmd);
54
55 __asm__("l.nop 13");
56
57 /* Give a grace period for failure to restart of 1s */
58 mdelay(1000);
59
60 /* Whoops - the platform was unable to reboot. Tell the user! */
61 pr_emerg("Reboot failed -- System halted\n");
62 while (1);
63}
64
65/*
66 * This is used if pm_power_off has not been set by a power management
67 * driver, in this case we can assume we are on a simulator. On
68 * OpenRISC simulators l.nop 1 will trigger the simulator exit.
69 */
70static void default_power_off(void)
71{
72 __asm__("l.nop 1");
73}
74
75/*
76 * Similar to machine_power_off, but don't shut off power. Add code
77 * here to freeze the system for e.g. post-mortem debug purpose when
78 * possible. This halt has nothing to do with the idle halt.
79 */
80void machine_halt(void)
81{
82 printk(KERN_INFO "*** MACHINE HALT ***\n");
83 __asm__("l.nop 1");
84}
85
86/* If or when software power-off is implemented, add code here. */
87void machine_power_off(void)
88{
89 printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
90 if (pm_power_off != NULL)
91 pm_power_off();
92 else
93 default_power_off();
94}
95
96/*
97 * Send the doze signal to the cpu if available.
98 * Make sure, that all interrupts are enabled
99 */
100void arch_cpu_idle(void)
101{
102 raw_local_irq_enable();
103 if (mfspr(SPR_UPR) & SPR_UPR_PMP)
104 mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
105}
106
107void (*pm_power_off)(void) = NULL;
108EXPORT_SYMBOL(pm_power_off);
109
110/*
111 * When a process does an "exec", machine state like FPU and debug
112 * registers need to be reset. This is a hook function for that.
113 * Currently we don't have any such state to reset, so this is empty.
114 */
115void flush_thread(void)
116{
117}
118
119void show_regs(struct pt_regs *regs)
120{
121 extern void show_registers(struct pt_regs *regs);
122
123 show_regs_print_info(KERN_DEFAULT);
124 /* __PHX__ cleanup this mess */
125 show_registers(regs);
126}
127
128/*
129 * Copy the thread-specific (arch specific) info from the current
130 * process to the new one p
131 */
132extern asmlinkage void ret_from_fork(void);
133
134/*
135 * copy_thread
136 * @clone_flags: flags
137 * @usp: user stack pointer or fn for kernel thread
138 * @arg: arg to fn for kernel thread; always NULL for userspace thread
139 * @p: the newly created task
140 * @tls: the Thread Local Storage pointer for the new process
141 *
142 * At the top of a newly initialized kernel stack are two stacked pt_reg
143 * structures. The first (topmost) is the userspace context of the thread.
144 * The second is the kernelspace context of the thread.
145 *
146 * A kernel thread will not be returning to userspace, so the topmost pt_regs
147 * struct can be uninitialized; it _does_ need to exist, though, because
148 * a kernel thread can become a userspace thread by doing a kernel_execve, in
149 * which case the topmost context will be initialized and used for 'returning'
150 * to userspace.
151 *
152 * The second pt_reg struct needs to be initialized to 'return' to
153 * ret_from_fork. A kernel thread will need to set r20 to the address of
154 * a function to call into (with arg in r22); userspace threads need to set
155 * r20 to NULL in which case ret_from_fork will just continue a return to
156 * userspace.
157 *
158 * A kernel thread 'fn' may return; this is effectively what happens when
159 * kernel_execve is called. In that case, the userspace pt_regs must have
160 * been initialized (which kernel_execve takes care of, see start_thread
161 * below); ret_from_fork will then continue its execution causing the
162 * 'kernel thread' to return to userspace as a userspace thread.
163 */
164
165int
166copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
167{
168 unsigned long clone_flags = args->flags;
169 unsigned long usp = args->stack;
170 unsigned long tls = args->tls;
171 struct pt_regs *userregs;
172 struct pt_regs *kregs;
173 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
174 unsigned long top_of_kernel_stack;
175
176 top_of_kernel_stack = sp;
177
178 /* Locate userspace context on stack... */
179 sp -= STACK_FRAME_OVERHEAD; /* redzone */
180 sp -= sizeof(struct pt_regs);
181 userregs = (struct pt_regs *) sp;
182
183 /* ...and kernel context */
184 sp -= STACK_FRAME_OVERHEAD; /* redzone */
185 sp -= sizeof(struct pt_regs);
186 kregs = (struct pt_regs *)sp;
187
188 if (unlikely(args->fn)) {
189 memset(kregs, 0, sizeof(struct pt_regs));
190 kregs->gpr[20] = (unsigned long)args->fn;
191 kregs->gpr[22] = (unsigned long)args->fn_arg;
192 } else {
193 *userregs = *current_pt_regs();
194
195 if (usp)
196 userregs->sp = usp;
197
198 /*
199 * For CLONE_SETTLS set "tp" (r10) to the TLS pointer.
200 */
201 if (clone_flags & CLONE_SETTLS)
202 userregs->gpr[10] = tls;
203
204 userregs->gpr[11] = 0; /* Result from fork() */
205
206 kregs->gpr[20] = 0; /* Userspace thread */
207 }
208
209 /*
210 * _switch wants the kernel stack page in pt_regs->sp so that it
211 * can restore it to thread_info->ksp... see _switch for details.
212 */
213 kregs->sp = top_of_kernel_stack;
214 kregs->gpr[9] = (unsigned long)ret_from_fork;
215
216 task_thread_info(p)->ksp = (unsigned long)kregs;
217
218 return 0;
219}
220
221/*
222 * Set up a thread for executing a new program
223 */
224void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
225{
226 unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
227
228 memset(regs, 0, sizeof(struct pt_regs));
229
230 regs->pc = pc;
231 regs->sr = sr;
232 regs->sp = sp;
233}
234
235extern struct thread_info *_switch(struct thread_info *old_ti,
236 struct thread_info *new_ti);
237extern int lwa_flag;
238
239struct task_struct *__switch_to(struct task_struct *old,
240 struct task_struct *new)
241{
242 struct task_struct *last;
243 struct thread_info *new_ti, *old_ti;
244 unsigned long flags;
245
246 local_irq_save(flags);
247
248 /* current_set is an array of saved current pointers
249 * (one for each cpu). we need them at user->kernel transition,
250 * while we save them at kernel->user transition
251 */
252 new_ti = new->stack;
253 old_ti = old->stack;
254
255 lwa_flag = 0;
256
257 current_thread_info_set[smp_processor_id()] = new_ti;
258 last = (_switch(old_ti, new_ti))->task;
259
260 local_irq_restore(flags);
261
262 return last;
263}
264
265/*
266 * Write out registers in core dump format, as defined by the
267 * struct user_regs_struct
268 */
269void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
270{
271 dest[0] = 0; /* r0 */
272 memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
273 dest[32] = regs->pc;
274 dest[33] = regs->sr;
275 dest[34] = 0;
276 dest[35] = 0;
277}
278
279unsigned long __get_wchan(struct task_struct *p)
280{
281 /* TODO */
282
283 return 0;
284}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * OpenRISC process.c
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
12 *
13 * This file handles the architecture-dependent parts of process handling...
14 */
15
16#define __KERNEL_SYSCALLS__
17#include <linux/cpu.h>
18#include <linux/errno.h>
19#include <linux/sched.h>
20#include <linux/sched/debug.h>
21#include <linux/sched/task.h>
22#include <linux/sched/task_stack.h>
23#include <linux/kernel.h>
24#include <linux/export.h>
25#include <linux/mm.h>
26#include <linux/stddef.h>
27#include <linux/unistd.h>
28#include <linux/ptrace.h>
29#include <linux/slab.h>
30#include <linux/elfcore.h>
31#include <linux/interrupt.h>
32#include <linux/delay.h>
33#include <linux/init_task.h>
34#include <linux/mqueue.h>
35#include <linux/fs.h>
36#include <linux/reboot.h>
37
38#include <linux/uaccess.h>
39#include <asm/io.h>
40#include <asm/processor.h>
41#include <asm/spr_defs.h>
42#include <asm/switch_to.h>
43
44#include <linux/smp.h>
45
46/*
47 * Pointer to Current thread info structure.
48 *
49 * Used at user space -> kernel transitions.
50 */
51struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
52
53void machine_restart(char *cmd)
54{
55 do_kernel_restart(cmd);
56
57 __asm__("l.nop 13");
58
59 /* Give a grace period for failure to restart of 1s */
60 mdelay(1000);
61
62 /* Whoops - the platform was unable to reboot. Tell the user! */
63 pr_emerg("Reboot failed -- System halted\n");
64 while (1);
65}
66
67/*
68 * This is used if a sys-off handler was not set by a power management
69 * driver, in this case we can assume we are on a simulator. On
70 * OpenRISC simulators l.nop 1 will trigger the simulator exit.
71 */
72static void default_power_off(void)
73{
74 __asm__("l.nop 1");
75}
76
77/*
78 * Similar to machine_power_off, but don't shut off power. Add code
79 * here to freeze the system for e.g. post-mortem debug purpose when
80 * possible. This halt has nothing to do with the idle halt.
81 */
82void machine_halt(void)
83{
84 printk(KERN_INFO "*** MACHINE HALT ***\n");
85 __asm__("l.nop 1");
86}
87
88/* If or when software power-off is implemented, add code here. */
89void machine_power_off(void)
90{
91 printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
92 do_kernel_power_off();
93 default_power_off();
94}
95
96/*
97 * Send the doze signal to the cpu if available.
98 * Make sure, that all interrupts are enabled
99 */
100void arch_cpu_idle(void)
101{
102 raw_local_irq_enable();
103 if (mfspr(SPR_UPR) & SPR_UPR_PMP)
104 mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
105 raw_local_irq_disable();
106}
107
108void (*pm_power_off)(void) = NULL;
109EXPORT_SYMBOL(pm_power_off);
110
111/*
112 * When a process does an "exec", machine state like FPU and debug
113 * registers need to be reset. This is a hook function for that.
114 * Currently we don't have any such state to reset, so this is empty.
115 */
116void flush_thread(void)
117{
118}
119
120void show_regs(struct pt_regs *regs)
121{
122 show_regs_print_info(KERN_DEFAULT);
123 /* __PHX__ cleanup this mess */
124 show_registers(regs);
125}
126
127/*
128 * Copy the thread-specific (arch specific) info from the current
129 * process to the new one p
130 */
131extern asmlinkage void ret_from_fork(void);
132
133/*
134 * copy_thread
135 * @clone_flags: flags
136 * @usp: user stack pointer or fn for kernel thread
137 * @arg: arg to fn for kernel thread; always NULL for userspace thread
138 * @p: the newly created task
139 * @tls: the Thread Local Storage pointer for the new process
140 *
141 * At the top of a newly initialized kernel stack are two stacked pt_reg
142 * structures. The first (topmost) is the userspace context of the thread.
143 * The second is the kernelspace context of the thread.
144 *
145 * A kernel thread will not be returning to userspace, so the topmost pt_regs
146 * struct can be uninitialized; it _does_ need to exist, though, because
147 * a kernel thread can become a userspace thread by doing a kernel_execve, in
148 * which case the topmost context will be initialized and used for 'returning'
149 * to userspace.
150 *
151 * The second pt_reg struct needs to be initialized to 'return' to
152 * ret_from_fork. A kernel thread will need to set r20 to the address of
153 * a function to call into (with arg in r22); userspace threads need to set
154 * r20 to NULL in which case ret_from_fork will just continue a return to
155 * userspace.
156 *
157 * A kernel thread 'fn' may return; this is effectively what happens when
158 * kernel_execve is called. In that case, the userspace pt_regs must have
159 * been initialized (which kernel_execve takes care of, see start_thread
160 * below); ret_from_fork will then continue its execution causing the
161 * 'kernel thread' to return to userspace as a userspace thread.
162 */
163
164int
165copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
166{
167 unsigned long clone_flags = args->flags;
168 unsigned long usp = args->stack;
169 unsigned long tls = args->tls;
170 struct pt_regs *userregs;
171 struct pt_regs *kregs;
172 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
173 unsigned long top_of_kernel_stack;
174
175 top_of_kernel_stack = sp;
176
177 /* Locate userspace context on stack... */
178 sp -= STACK_FRAME_OVERHEAD; /* redzone */
179 sp -= sizeof(struct pt_regs);
180 userregs = (struct pt_regs *) sp;
181
182 /* ...and kernel context */
183 sp -= STACK_FRAME_OVERHEAD; /* redzone */
184 sp -= sizeof(struct pt_regs);
185 kregs = (struct pt_regs *)sp;
186
187 if (unlikely(args->fn)) {
188 memset(kregs, 0, sizeof(struct pt_regs));
189 kregs->gpr[20] = (unsigned long)args->fn;
190 kregs->gpr[22] = (unsigned long)args->fn_arg;
191 } else {
192 *userregs = *current_pt_regs();
193
194 if (usp)
195 userregs->sp = usp;
196
197 /*
198 * For CLONE_SETTLS set "tp" (r10) to the TLS pointer.
199 */
200 if (clone_flags & CLONE_SETTLS)
201 userregs->gpr[10] = tls;
202
203 userregs->gpr[11] = 0; /* Result from fork() */
204
205 kregs->gpr[20] = 0; /* Userspace thread */
206 }
207
208 /*
209 * _switch wants the kernel stack page in pt_regs->sp so that it
210 * can restore it to thread_info->ksp... see _switch for details.
211 */
212 kregs->sp = top_of_kernel_stack;
213 kregs->gpr[9] = (unsigned long)ret_from_fork;
214
215 task_thread_info(p)->ksp = (unsigned long)kregs;
216
217 return 0;
218}
219
220/*
221 * Set up a thread for executing a new program
222 */
223void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
224{
225 unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
226
227 memset(regs, 0, sizeof(struct pt_regs));
228
229 regs->pc = pc;
230 regs->sr = sr;
231 regs->sp = sp;
232}
233
234extern struct thread_info *_switch(struct thread_info *old_ti,
235 struct thread_info *new_ti);
236extern int lwa_flag;
237
238struct task_struct *__switch_to(struct task_struct *old,
239 struct task_struct *new)
240{
241 struct task_struct *last;
242 struct thread_info *new_ti, *old_ti;
243 unsigned long flags;
244
245 local_irq_save(flags);
246
247 /* current_set is an array of saved current pointers
248 * (one for each cpu). we need them at user->kernel transition,
249 * while we save them at kernel->user transition
250 */
251 new_ti = new->stack;
252 old_ti = old->stack;
253
254 lwa_flag = 0;
255
256 current_thread_info_set[smp_processor_id()] = new_ti;
257 last = (_switch(old_ti, new_ti))->task;
258
259 local_irq_restore(flags);
260
261 return last;
262}
263
264/*
265 * Write out registers in core dump format, as defined by the
266 * struct user_regs_struct
267 */
268void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
269{
270 dest[0] = 0; /* r0 */
271 memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
272 dest[32] = regs->pc;
273 dest[33] = regs->sr;
274 dest[34] = 0;
275 dest[35] = 0;
276}
277
278unsigned long __get_wchan(struct task_struct *p)
279{
280 /* TODO */
281
282 return 0;
283}