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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/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}
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/kernel.h>
26#include <linux/module.h>
27#include <linux/mm.h>
28#include <linux/stddef.h>
29#include <linux/unistd.h>
30#include <linux/ptrace.h>
31#include <linux/slab.h>
32#include <linux/elfcore.h>
33#include <linux/interrupt.h>
34#include <linux/delay.h>
35#include <linux/init_task.h>
36#include <linux/mqueue.h>
37#include <linux/fs.h>
38
39#include <asm/uaccess.h>
40#include <asm/pgtable.h>
41#include <asm/io.h>
42#include <asm/processor.h>
43#include <asm/spr_defs.h>
44
45#include <linux/smp.h>
46
47/*
48 * Pointer to Current thread info structure.
49 *
50 * Used at user space -> kernel transitions.
51 */
52struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
53
54void machine_restart(void)
55{
56 printk(KERN_INFO "*** MACHINE RESTART ***\n");
57 __asm__("l.nop 1");
58}
59
60/*
61 * Similar to machine_power_off, but don't shut off power. Add code
62 * here to freeze the system for e.g. post-mortem debug purpose when
63 * possible. This halt has nothing to do with the idle halt.
64 */
65void machine_halt(void)
66{
67 printk(KERN_INFO "*** MACHINE HALT ***\n");
68 __asm__("l.nop 1");
69}
70
71/* If or when software power-off is implemented, add code here. */
72void machine_power_off(void)
73{
74 printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
75 __asm__("l.nop 1");
76}
77
78void (*pm_power_off) (void) = machine_power_off;
79
80/*
81 * When a process does an "exec", machine state like FPU and debug
82 * registers need to be reset. This is a hook function for that.
83 * Currently we don't have any such state to reset, so this is empty.
84 */
85void flush_thread(void)
86{
87}
88
89void show_regs(struct pt_regs *regs)
90{
91 extern void show_registers(struct pt_regs *regs);
92
93 /* __PHX__ cleanup this mess */
94 show_registers(regs);
95}
96
97unsigned long thread_saved_pc(struct task_struct *t)
98{
99 return (unsigned long)user_regs(t->stack)->pc;
100}
101
102void release_thread(struct task_struct *dead_task)
103{
104}
105
106/*
107 * Copy the thread-specific (arch specific) info from the current
108 * process to the new one p
109 */
110extern asmlinkage void ret_from_fork(void);
111
112int
113copy_thread(unsigned long clone_flags, unsigned long usp,
114 unsigned long unused, struct task_struct *p, struct pt_regs *regs)
115{
116 struct pt_regs *childregs;
117 struct pt_regs *kregs;
118 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
119 struct thread_info *ti;
120 unsigned long top_of_kernel_stack;
121
122 top_of_kernel_stack = sp;
123
124 p->set_child_tid = p->clear_child_tid = NULL;
125
126 /* Copy registers */
127 /* redzone */
128 sp -= STACK_FRAME_OVERHEAD;
129 sp -= sizeof(struct pt_regs);
130 childregs = (struct pt_regs *)sp;
131
132 /* Copy parent registers */
133 *childregs = *regs;
134
135 if ((childregs->sr & SPR_SR_SM) == 1) {
136 /* for kernel thread, set `current_thread_info'
137 * and stackptr in new task
138 */
139 childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
140 childregs->gpr[10] = (unsigned long)task_thread_info(p);
141 } else {
142 childregs->sp = usp;
143 }
144
145 childregs->gpr[11] = 0; /* Result from fork() */
146
147 /*
148 * The way this works is that at some point in the future
149 * some task will call _switch to switch to the new task.
150 * That will pop off the stack frame created below and start
151 * the new task running at ret_from_fork. The new task will
152 * do some house keeping and then return from the fork or clone
153 * system call, using the stack frame created above.
154 */
155 /* redzone */
156 sp -= STACK_FRAME_OVERHEAD;
157 sp -= sizeof(struct pt_regs);
158 kregs = (struct pt_regs *)sp;
159
160 ti = task_thread_info(p);
161 ti->ksp = sp;
162
163 /* kregs->sp must store the location of the 'pre-switch' kernel stack
164 * pointer... for a newly forked process, this is simply the top of
165 * the kernel stack.
166 */
167 kregs->sp = top_of_kernel_stack;
168 kregs->gpr[3] = (unsigned long)current; /* arg to schedule_tail */
169 kregs->gpr[10] = (unsigned long)task_thread_info(p);
170 kregs->gpr[9] = (unsigned long)ret_from_fork;
171
172 return 0;
173}
174
175/*
176 * Set up a thread for executing a new program
177 */
178void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
179{
180 unsigned long sr = regs->sr & ~SPR_SR_SM;
181
182 set_fs(USER_DS);
183 memset(regs->gpr, 0, sizeof(regs->gpr));
184
185 regs->pc = pc;
186 regs->sr = sr;
187 regs->sp = sp;
188
189/* printk("start thread, ksp = %lx\n", current_thread_info()->ksp);*/
190}
191
192/* Fill in the fpu structure for a core dump. */
193int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu)
194{
195 /* TODO */
196 return 0;
197}
198
199extern struct thread_info *_switch(struct thread_info *old_ti,
200 struct thread_info *new_ti);
201
202struct task_struct *__switch_to(struct task_struct *old,
203 struct task_struct *new)
204{
205 struct task_struct *last;
206 struct thread_info *new_ti, *old_ti;
207 unsigned long flags;
208
209 local_irq_save(flags);
210
211 /* current_set is an array of saved current pointers
212 * (one for each cpu). we need them at user->kernel transition,
213 * while we save them at kernel->user transition
214 */
215 new_ti = new->stack;
216 old_ti = old->stack;
217
218 current_thread_info_set[smp_processor_id()] = new_ti;
219 last = (_switch(old_ti, new_ti))->task;
220
221 local_irq_restore(flags);
222
223 return last;
224}
225
226/*
227 * Write out registers in core dump format, as defined by the
228 * struct user_regs_struct
229 */
230void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
231{
232 dest[0] = 0; /* r0 */
233 memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
234 dest[32] = regs->pc;
235 dest[33] = regs->sr;
236 dest[34] = 0;
237 dest[35] = 0;
238}
239
240extern void _kernel_thread_helper(void);
241
242void __noreturn kernel_thread_helper(int (*fn) (void *), void *arg)
243{
244 do_exit(fn(arg));
245}
246
247/*
248 * Create a kernel thread.
249 */
250int kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
251{
252 struct pt_regs regs;
253
254 memset(®s, 0, sizeof(regs));
255
256 regs.gpr[20] = (unsigned long)fn;
257 regs.gpr[22] = (unsigned long)arg;
258 regs.sr = mfspr(SPR_SR);
259 regs.pc = (unsigned long)_kernel_thread_helper;
260
261 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
262 0, ®s, 0, NULL, NULL);
263}
264
265/*
266 * sys_execve() executes a new program.
267 */
268asmlinkage long _sys_execve(const char __user *name,
269 const char __user * const __user *argv,
270 const char __user * const __user *envp,
271 struct pt_regs *regs)
272{
273 int error;
274 char *filename;
275
276 filename = getname(name);
277 error = PTR_ERR(filename);
278
279 if (IS_ERR(filename))
280 goto out;
281
282 error = do_execve(filename, argv, envp, regs);
283 putname(filename);
284
285out:
286 return error;
287}
288
289unsigned long get_wchan(struct task_struct *p)
290{
291 /* TODO */
292
293 return 0;
294}
295
296int kernel_execve(const char *filename, char *const argv[], char *const envp[])
297{
298 register long __res asm("r11") = __NR_execve;
299 register long __a asm("r3") = (long)(filename);
300 register long __b asm("r4") = (long)(argv);
301 register long __c asm("r5") = (long)(envp);
302 __asm__ volatile ("l.sys 1"
303 : "=r" (__res), "=r"(__a), "=r"(__b), "=r"(__c)
304 : "0"(__res), "1"(__a), "2"(__b), "3"(__c)
305 : "r6", "r7", "r8", "r12", "r13", "r15",
306 "r17", "r19", "r21", "r23", "r25", "r27",
307 "r29", "r31");
308 __asm__ volatile ("l.nop");
309 return __res;
310}