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