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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/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/system.h>
42#include <asm/io.h>
43#include <asm/processor.h>
44#include <asm/spr_defs.h>
45
46#include <linux/smp.h>
47
48/*
49 * Pointer to Current thread info structure.
50 *
51 * Used at user space -> kernel transitions.
52 */
53struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
54
55void machine_restart(void)
56{
57 printk(KERN_INFO "*** MACHINE RESTART ***\n");
58 __asm__("l.nop 1");
59}
60
61/*
62 * Similar to machine_power_off, but don't shut off power. Add code
63 * here to freeze the system for e.g. post-mortem debug purpose when
64 * possible. This halt has nothing to do with the idle halt.
65 */
66void machine_halt(void)
67{
68 printk(KERN_INFO "*** MACHINE HALT ***\n");
69 __asm__("l.nop 1");
70}
71
72/* If or when software power-off is implemented, add code here. */
73void machine_power_off(void)
74{
75 printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
76 __asm__("l.nop 1");
77}
78
79void (*pm_power_off) (void) = machine_power_off;
80
81/*
82 * When a process does an "exec", machine state like FPU and debug
83 * registers need to be reset. This is a hook function for that.
84 * Currently we don't have any such state to reset, so this is empty.
85 */
86void flush_thread(void)
87{
88}
89
90void show_regs(struct pt_regs *regs)
91{
92 extern void show_registers(struct pt_regs *regs);
93
94 /* __PHX__ cleanup this mess */
95 show_registers(regs);
96}
97
98unsigned long thread_saved_pc(struct task_struct *t)
99{
100 return (unsigned long)user_regs(t->stack)->pc;
101}
102
103void release_thread(struct task_struct *dead_task)
104{
105}
106
107/*
108 * Copy the thread-specific (arch specific) info from the current
109 * process to the new one p
110 */
111extern asmlinkage void ret_from_fork(void);
112
113int
114copy_thread(unsigned long clone_flags, unsigned long usp,
115 unsigned long unused, struct task_struct *p, struct pt_regs *regs)
116{
117 struct pt_regs *childregs;
118 struct pt_regs *kregs;
119 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
120 struct thread_info *ti;
121 unsigned long top_of_kernel_stack;
122
123 top_of_kernel_stack = sp;
124
125 p->set_child_tid = p->clear_child_tid = NULL;
126
127 /* Copy registers */
128 /* redzone */
129 sp -= STACK_FRAME_OVERHEAD;
130 sp -= sizeof(struct pt_regs);
131 childregs = (struct pt_regs *)sp;
132
133 /* Copy parent registers */
134 *childregs = *regs;
135
136 if ((childregs->sr & SPR_SR_SM) == 1) {
137 /* for kernel thread, set `current_thread_info'
138 * and stackptr in new task
139 */
140 childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
141 childregs->gpr[10] = (unsigned long)task_thread_info(p);
142 } else {
143 childregs->sp = usp;
144 }
145
146 childregs->gpr[11] = 0; /* Result from fork() */
147
148 /*
149 * The way this works is that at some point in the future
150 * some task will call _switch to switch to the new task.
151 * That will pop off the stack frame created below and start
152 * the new task running at ret_from_fork. The new task will
153 * do some house keeping and then return from the fork or clone
154 * system call, using the stack frame created above.
155 */
156 /* redzone */
157 sp -= STACK_FRAME_OVERHEAD;
158 sp -= sizeof(struct pt_regs);
159 kregs = (struct pt_regs *)sp;
160
161 ti = task_thread_info(p);
162 ti->ksp = sp;
163
164 /* kregs->sp must store the location of the 'pre-switch' kernel stack
165 * pointer... for a newly forked process, this is simply the top of
166 * the kernel stack.
167 */
168 kregs->sp = top_of_kernel_stack;
169 kregs->gpr[3] = (unsigned long)current; /* arg to schedule_tail */
170 kregs->gpr[10] = (unsigned long)task_thread_info(p);
171 kregs->gpr[9] = (unsigned long)ret_from_fork;
172
173 return 0;
174}
175
176/*
177 * Set up a thread for executing a new program
178 */
179void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
180{
181 unsigned long sr = regs->sr & ~SPR_SR_SM;
182
183 set_fs(USER_DS);
184 memset(regs->gpr, 0, sizeof(regs->gpr));
185
186 regs->pc = pc;
187 regs->sr = sr;
188 regs->sp = sp;
189
190/* printk("start thread, ksp = %lx\n", current_thread_info()->ksp);*/
191}
192
193/* Fill in the fpu structure for a core dump. */
194int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu)
195{
196 /* TODO */
197 return 0;
198}
199
200extern struct thread_info *_switch(struct thread_info *old_ti,
201 struct thread_info *new_ti);
202
203struct task_struct *__switch_to(struct task_struct *old,
204 struct task_struct *new)
205{
206 struct task_struct *last;
207 struct thread_info *new_ti, *old_ti;
208 unsigned long flags;
209
210 local_irq_save(flags);
211
212 /* current_set is an array of saved current pointers
213 * (one for each cpu). we need them at user->kernel transition,
214 * while we save them at kernel->user transition
215 */
216 new_ti = new->stack;
217 old_ti = old->stack;
218
219 current_thread_info_set[smp_processor_id()] = new_ti;
220 last = (_switch(old_ti, new_ti))->task;
221
222 local_irq_restore(flags);
223
224 return last;
225}
226
227/*
228 * Write out registers in core dump format, as defined by the
229 * struct user_regs_struct
230 */
231void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
232{
233 dest[0] = 0; /* r0 */
234 memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
235 dest[32] = regs->pc;
236 dest[33] = regs->sr;
237 dest[34] = 0;
238 dest[35] = 0;
239}
240
241extern void _kernel_thread_helper(void);
242
243void __noreturn kernel_thread_helper(int (*fn) (void *), void *arg)
244{
245 do_exit(fn(arg));
246}
247
248/*
249 * Create a kernel thread.
250 */
251int kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
252{
253 struct pt_regs regs;
254
255 memset(®s, 0, sizeof(regs));
256
257 regs.gpr[20] = (unsigned long)fn;
258 regs.gpr[22] = (unsigned long)arg;
259 regs.sr = mfspr(SPR_SR);
260 regs.pc = (unsigned long)_kernel_thread_helper;
261
262 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
263 0, ®s, 0, NULL, NULL);
264}
265
266/*
267 * sys_execve() executes a new program.
268 */
269asmlinkage long _sys_execve(const char __user *name,
270 const char __user * const __user *argv,
271 const char __user * const __user *envp,
272 struct pt_regs *regs)
273{
274 int error;
275 char *filename;
276
277 filename = getname(name);
278 error = PTR_ERR(filename);
279
280 if (IS_ERR(filename))
281 goto out;
282
283 error = do_execve(filename, argv, envp, regs);
284 putname(filename);
285
286out:
287 return error;
288}
289
290unsigned long get_wchan(struct task_struct *p)
291{
292 /* TODO */
293
294 return 0;
295}
296
297int kernel_execve(const char *filename, char *const argv[], char *const envp[])
298{
299 register long __res asm("r11") = __NR_execve;
300 register long __a asm("r3") = (long)(filename);
301 register long __b asm("r4") = (long)(argv);
302 register long __c asm("r5") = (long)(envp);
303 __asm__ volatile ("l.sys 1"
304 : "=r" (__res), "=r"(__a), "=r"(__b), "=r"(__c)
305 : "0"(__res), "1"(__a), "2"(__b), "3"(__c)
306 : "r6", "r7", "r8", "r12", "r13", "r15",
307 "r17", "r19", "r21", "r23", "r25", "r27",
308 "r29", "r31");
309 __asm__ volatile ("l.nop");
310 return __res;
311}
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/fpu.h>
40#include <asm/io.h>
41#include <asm/processor.h>
42#include <asm/spr_defs.h>
43#include <asm/switch_to.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(char *cmd)
55{
56 do_kernel_restart(cmd);
57
58 __asm__("l.nop 13");
59
60 /* Give a grace period for failure to restart of 1s */
61 mdelay(1000);
62
63 /* Whoops - the platform was unable to reboot. Tell the user! */
64 pr_emerg("Reboot failed -- System halted\n");
65 while (1);
66}
67
68/*
69 * This is used if a sys-off handler was not set by a power management
70 * driver, in this case we can assume we are on a simulator. On
71 * OpenRISC simulators l.nop 1 will trigger the simulator exit.
72 */
73static void default_power_off(void)
74{
75 __asm__("l.nop 1");
76}
77
78/*
79 * Similar to machine_power_off, but don't shut off power. Add code
80 * here to freeze the system for e.g. post-mortem debug purpose when
81 * possible. This halt has nothing to do with the idle halt.
82 */
83void machine_halt(void)
84{
85 printk(KERN_INFO "*** MACHINE HALT ***\n");
86 __asm__("l.nop 1");
87}
88
89/* If or when software power-off is implemented, add code here. */
90void machine_power_off(void)
91{
92 printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
93 do_kernel_power_off();
94 default_power_off();
95}
96
97/*
98 * Send the doze signal to the cpu if available.
99 * Make sure, that all interrupts are enabled
100 */
101void arch_cpu_idle(void)
102{
103 raw_local_irq_enable();
104 if (mfspr(SPR_UPR) & SPR_UPR_PMP)
105 mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
106 raw_local_irq_disable();
107}
108
109void (*pm_power_off)(void) = NULL;
110EXPORT_SYMBOL(pm_power_off);
111
112/*
113 * When a process does an "exec", machine state like FPU and debug
114 * registers need to be reset. This is a hook function for that.
115 * Currently we don't have any such state to reset, so this is empty.
116 */
117void flush_thread(void)
118{
119}
120
121void show_regs(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 save_fpu(current);
249
250 /* current_set is an array of saved current pointers
251 * (one for each cpu). we need them at user->kernel transition,
252 * while we save them at kernel->user transition
253 */
254 new_ti = new->stack;
255 old_ti = old->stack;
256
257 lwa_flag = 0;
258
259 current_thread_info_set[smp_processor_id()] = new_ti;
260 last = (_switch(old_ti, new_ti))->task;
261
262 restore_fpu(current);
263
264 local_irq_restore(flags);
265
266 return last;
267}
268
269/*
270 * Write out registers in core dump format, as defined by the
271 * struct user_regs_struct
272 */
273void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
274{
275 dest[0] = 0; /* r0 */
276 memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
277 dest[32] = regs->pc;
278 dest[33] = regs->sr;
279 dest[34] = 0;
280 dest[35] = 0;
281}
282
283unsigned long __get_wchan(struct task_struct *p)
284{
285 /* TODO */
286
287 return 0;
288}