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1/*
2 * OpenRISC process.c
3 *
4 * Linux architectural port borrowing liberally from similar works of
5 * others. All original copyrights apply as per the original source
6 * declaration.
7 *
8 * Modifications for the OpenRISC architecture:
9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 *
17 * This file handles the architecture-dependent parts of process handling...
18 */
19
20#define __KERNEL_SYSCALLS__
21#include <stdarg.h>
22
23#include <linux/errno.h>
24#include <linux/sched.h>
25#include <linux/sched/debug.h>
26#include <linux/sched/task.h>
27#include <linux/sched/task_stack.h>
28#include <linux/kernel.h>
29#include <linux/export.h>
30#include <linux/mm.h>
31#include <linux/stddef.h>
32#include <linux/unistd.h>
33#include <linux/ptrace.h>
34#include <linux/slab.h>
35#include <linux/elfcore.h>
36#include <linux/interrupt.h>
37#include <linux/delay.h>
38#include <linux/init_task.h>
39#include <linux/mqueue.h>
40#include <linux/fs.h>
41
42#include <linux/uaccess.h>
43#include <asm/pgtable.h>
44#include <asm/io.h>
45#include <asm/processor.h>
46#include <asm/spr_defs.h>
47
48#include <linux/smp.h>
49
50/*
51 * Pointer to Current thread info structure.
52 *
53 * Used at user space -> kernel transitions.
54 */
55struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
56
57void machine_restart(void)
58{
59 printk(KERN_INFO "*** MACHINE RESTART ***\n");
60 __asm__("l.nop 1");
61}
62
63/*
64 * Similar to machine_power_off, but don't shut off power. Add code
65 * here to freeze the system for e.g. post-mortem debug purpose when
66 * possible. This halt has nothing to do with the idle halt.
67 */
68void machine_halt(void)
69{
70 printk(KERN_INFO "*** MACHINE HALT ***\n");
71 __asm__("l.nop 1");
72}
73
74/* If or when software power-off is implemented, add code here. */
75void machine_power_off(void)
76{
77 printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
78 __asm__("l.nop 1");
79}
80
81/*
82 * Send the doze signal to the cpu if available.
83 * Make sure, that all interrupts are enabled
84 */
85void arch_cpu_idle(void)
86{
87 local_irq_enable();
88 if (mfspr(SPR_UPR) & SPR_UPR_PMP)
89 mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
90}
91
92void (*pm_power_off) (void) = machine_power_off;
93EXPORT_SYMBOL(pm_power_off);
94
95/*
96 * When a process does an "exec", machine state like FPU and debug
97 * registers need to be reset. This is a hook function for that.
98 * Currently we don't have any such state to reset, so this is empty.
99 */
100void flush_thread(void)
101{
102}
103
104void show_regs(struct pt_regs *regs)
105{
106 extern void show_registers(struct pt_regs *regs);
107
108 show_regs_print_info(KERN_DEFAULT);
109 /* __PHX__ cleanup this mess */
110 show_registers(regs);
111}
112
113void release_thread(struct task_struct *dead_task)
114{
115}
116
117/*
118 * Copy the thread-specific (arch specific) info from the current
119 * process to the new one p
120 */
121extern asmlinkage void ret_from_fork(void);
122
123/*
124 * copy_thread
125 * @clone_flags: flags
126 * @usp: user stack pointer or fn for kernel thread
127 * @arg: arg to fn for kernel thread; always NULL for userspace thread
128 * @p: the newly created task
129 * @regs: CPU context to copy for userspace thread; always NULL for kthread
130 *
131 * At the top of a newly initialized kernel stack are two stacked pt_reg
132 * structures. The first (topmost) is the userspace context of the thread.
133 * The second is the kernelspace context of the thread.
134 *
135 * A kernel thread will not be returning to userspace, so the topmost pt_regs
136 * struct can be uninitialized; it _does_ need to exist, though, because
137 * a kernel thread can become a userspace thread by doing a kernel_execve, in
138 * which case the topmost context will be initialized and used for 'returning'
139 * to userspace.
140 *
141 * The second pt_reg struct needs to be initialized to 'return' to
142 * ret_from_fork. A kernel thread will need to set r20 to the address of
143 * a function to call into (with arg in r22); userspace threads need to set
144 * r20 to NULL in which case ret_from_fork will just continue a return to
145 * userspace.
146 *
147 * A kernel thread 'fn' may return; this is effectively what happens when
148 * kernel_execve is called. In that case, the userspace pt_regs must have
149 * been initialized (which kernel_execve takes care of, see start_thread
150 * below); ret_from_fork will then continue its execution causing the
151 * 'kernel thread' to return to userspace as a userspace thread.
152 */
153
154int
155copy_thread(unsigned long clone_flags, unsigned long usp,
156 unsigned long arg, struct task_struct *p)
157{
158 struct pt_regs *userregs;
159 struct pt_regs *kregs;
160 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
161 unsigned long top_of_kernel_stack;
162
163 top_of_kernel_stack = sp;
164
165 /* Locate userspace context on stack... */
166 sp -= STACK_FRAME_OVERHEAD; /* redzone */
167 sp -= sizeof(struct pt_regs);
168 userregs = (struct pt_regs *) sp;
169
170 /* ...and kernel context */
171 sp -= STACK_FRAME_OVERHEAD; /* redzone */
172 sp -= sizeof(struct pt_regs);
173 kregs = (struct pt_regs *)sp;
174
175 if (unlikely(p->flags & PF_KTHREAD)) {
176 memset(kregs, 0, sizeof(struct pt_regs));
177 kregs->gpr[20] = usp; /* fn, kernel thread */
178 kregs->gpr[22] = arg;
179 } else {
180 *userregs = *current_pt_regs();
181
182 if (usp)
183 userregs->sp = usp;
184
185 /*
186 * For CLONE_SETTLS set "tp" (r10) to the TLS pointer passed to sys_clone.
187 *
188 * The kernel entry is:
189 * int clone (long flags, void *child_stack, int *parent_tid,
190 * int *child_tid, struct void *tls)
191 *
192 * This makes the source r7 in the kernel registers.
193 */
194 if (clone_flags & CLONE_SETTLS)
195 userregs->gpr[10] = userregs->gpr[7];
196
197 userregs->gpr[11] = 0; /* Result from fork() */
198
199 kregs->gpr[20] = 0; /* Userspace thread */
200 }
201
202 /*
203 * _switch wants the kernel stack page in pt_regs->sp so that it
204 * can restore it to thread_info->ksp... see _switch for details.
205 */
206 kregs->sp = top_of_kernel_stack;
207 kregs->gpr[9] = (unsigned long)ret_from_fork;
208
209 task_thread_info(p)->ksp = (unsigned long)kregs;
210
211 return 0;
212}
213
214/*
215 * Set up a thread for executing a new program
216 */
217void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
218{
219 unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
220
221 memset(regs, 0, sizeof(struct pt_regs));
222
223 regs->pc = pc;
224 regs->sr = sr;
225 regs->sp = sp;
226}
227
228/* Fill in the fpu structure for a core dump. */
229int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu)
230{
231 /* TODO */
232 return 0;
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 pm_power_off has not been 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 if (pm_power_off != NULL)
93 pm_power_off();
94 else
95 default_power_off();
96}
97
98/*
99 * Send the doze signal to the cpu if available.
100 * Make sure, that all interrupts are enabled
101 */
102void arch_cpu_idle(void)
103{
104 raw_local_irq_enable();
105 if (mfspr(SPR_UPR) & SPR_UPR_PMP)
106 mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
107 raw_local_irq_disable();
108}
109
110void (*pm_power_off)(void) = NULL;
111EXPORT_SYMBOL(pm_power_off);
112
113/*
114 * When a process does an "exec", machine state like FPU and debug
115 * registers need to be reset. This is a hook function for that.
116 * Currently we don't have any such state to reset, so this is empty.
117 */
118void flush_thread(void)
119{
120}
121
122void show_regs(struct pt_regs *regs)
123{
124 show_regs_print_info(KERN_DEFAULT);
125 /* __PHX__ cleanup this mess */
126 show_registers(regs);
127}
128
129/*
130 * Copy the thread-specific (arch specific) info from the current
131 * process to the new one p
132 */
133extern asmlinkage void ret_from_fork(void);
134
135/*
136 * copy_thread
137 * @clone_flags: flags
138 * @usp: user stack pointer or fn for kernel thread
139 * @arg: arg to fn for kernel thread; always NULL for userspace thread
140 * @p: the newly created task
141 * @tls: the Thread Local Storage pointer for the new process
142 *
143 * At the top of a newly initialized kernel stack are two stacked pt_reg
144 * structures. The first (topmost) is the userspace context of the thread.
145 * The second is the kernelspace context of the thread.
146 *
147 * A kernel thread will not be returning to userspace, so the topmost pt_regs
148 * struct can be uninitialized; it _does_ need to exist, though, because
149 * a kernel thread can become a userspace thread by doing a kernel_execve, in
150 * which case the topmost context will be initialized and used for 'returning'
151 * to userspace.
152 *
153 * The second pt_reg struct needs to be initialized to 'return' to
154 * ret_from_fork. A kernel thread will need to set r20 to the address of
155 * a function to call into (with arg in r22); userspace threads need to set
156 * r20 to NULL in which case ret_from_fork will just continue a return to
157 * userspace.
158 *
159 * A kernel thread 'fn' may return; this is effectively what happens when
160 * kernel_execve is called. In that case, the userspace pt_regs must have
161 * been initialized (which kernel_execve takes care of, see start_thread
162 * below); ret_from_fork will then continue its execution causing the
163 * 'kernel thread' to return to userspace as a userspace thread.
164 */
165
166int
167copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
168{
169 unsigned long clone_flags = args->flags;
170 unsigned long usp = args->stack;
171 unsigned long tls = args->tls;
172 struct pt_regs *userregs;
173 struct pt_regs *kregs;
174 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
175 unsigned long top_of_kernel_stack;
176
177 top_of_kernel_stack = sp;
178
179 /* Locate userspace context on stack... */
180 sp -= STACK_FRAME_OVERHEAD; /* redzone */
181 sp -= sizeof(struct pt_regs);
182 userregs = (struct pt_regs *) sp;
183
184 /* ...and kernel context */
185 sp -= STACK_FRAME_OVERHEAD; /* redzone */
186 sp -= sizeof(struct pt_regs);
187 kregs = (struct pt_regs *)sp;
188
189 if (unlikely(args->fn)) {
190 memset(kregs, 0, sizeof(struct pt_regs));
191 kregs->gpr[20] = (unsigned long)args->fn;
192 kregs->gpr[22] = (unsigned long)args->fn_arg;
193 } else {
194 *userregs = *current_pt_regs();
195
196 if (usp)
197 userregs->sp = usp;
198
199 /*
200 * For CLONE_SETTLS set "tp" (r10) to the TLS pointer.
201 */
202 if (clone_flags & CLONE_SETTLS)
203 userregs->gpr[10] = tls;
204
205 userregs->gpr[11] = 0; /* Result from fork() */
206
207 kregs->gpr[20] = 0; /* Userspace thread */
208 }
209
210 /*
211 * _switch wants the kernel stack page in pt_regs->sp so that it
212 * can restore it to thread_info->ksp... see _switch for details.
213 */
214 kregs->sp = top_of_kernel_stack;
215 kregs->gpr[9] = (unsigned long)ret_from_fork;
216
217 task_thread_info(p)->ksp = (unsigned long)kregs;
218
219 return 0;
220}
221
222/*
223 * Set up a thread for executing a new program
224 */
225void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
226{
227 unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
228
229 memset(regs, 0, sizeof(struct pt_regs));
230
231 regs->pc = pc;
232 regs->sr = sr;
233 regs->sp = sp;
234}
235
236extern struct thread_info *_switch(struct thread_info *old_ti,
237 struct thread_info *new_ti);
238extern int lwa_flag;
239
240struct task_struct *__switch_to(struct task_struct *old,
241 struct task_struct *new)
242{
243 struct task_struct *last;
244 struct thread_info *new_ti, *old_ti;
245 unsigned long flags;
246
247 local_irq_save(flags);
248
249 /* current_set is an array of saved current pointers
250 * (one for each cpu). we need them at user->kernel transition,
251 * while we save them at kernel->user transition
252 */
253 new_ti = new->stack;
254 old_ti = old->stack;
255
256 lwa_flag = 0;
257
258 current_thread_info_set[smp_processor_id()] = new_ti;
259 last = (_switch(old_ti, new_ti))->task;
260
261 local_irq_restore(flags);
262
263 return last;
264}
265
266/*
267 * Write out registers in core dump format, as defined by the
268 * struct user_regs_struct
269 */
270void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
271{
272 dest[0] = 0; /* r0 */
273 memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
274 dest[32] = regs->pc;
275 dest[33] = regs->sr;
276 dest[34] = 0;
277 dest[35] = 0;
278}
279
280unsigned long __get_wchan(struct task_struct *p)
281{
282 /* TODO */
283
284 return 0;
285}