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88ef7f3f JB |
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> | |
b17b0153 | 25 | #include <linux/sched/debug.h> |
29930025 | 26 | #include <linux/sched/task.h> |
68db0cf1 | 27 | #include <linux/sched/task_stack.h> |
88ef7f3f JB |
28 | #include <linux/kernel.h> |
29 | #include <linux/module.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 | ||
7c0f6ba6 | 42 | #include <linux/uaccess.h> |
88ef7f3f | 43 | #include <asm/pgtable.h> |
88ef7f3f JB |
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 | */ | |
55 | struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, }; | |
56 | ||
57 | void 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 | */ | |
68 | void 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. */ | |
75 | void machine_power_off(void) | |
76 | { | |
77 | printk(KERN_INFO "*** MACHINE POWER OFF ***\n"); | |
78 | __asm__("l.nop 1"); | |
79 | } | |
80 | ||
e29d11c6 SM |
81 | /* |
82 | * Send the doze signal to the cpu if available. | |
83 | * Make sure, that all interrupts are enabled | |
84 | */ | |
85 | void 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 | ||
88ef7f3f JB |
92 | void (*pm_power_off) (void) = machine_power_off; |
93 | ||
94 | /* | |
95 | * When a process does an "exec", machine state like FPU and debug | |
96 | * registers need to be reset. This is a hook function for that. | |
97 | * Currently we don't have any such state to reset, so this is empty. | |
98 | */ | |
99 | void flush_thread(void) | |
100 | { | |
101 | } | |
102 | ||
103 | void show_regs(struct pt_regs *regs) | |
104 | { | |
105 | extern void show_registers(struct pt_regs *regs); | |
106 | ||
a43cb95d | 107 | show_regs_print_info(KERN_DEFAULT); |
88ef7f3f JB |
108 | /* __PHX__ cleanup this mess */ |
109 | show_registers(regs); | |
110 | } | |
111 | ||
112 | unsigned long thread_saved_pc(struct task_struct *t) | |
113 | { | |
114 | return (unsigned long)user_regs(t->stack)->pc; | |
115 | } | |
116 | ||
117 | void release_thread(struct task_struct *dead_task) | |
118 | { | |
119 | } | |
120 | ||
121 | /* | |
122 | * Copy the thread-specific (arch specific) info from the current | |
123 | * process to the new one p | |
124 | */ | |
125 | extern asmlinkage void ret_from_fork(void); | |
126 | ||
cbf23cf1 JB |
127 | /* |
128 | * copy_thread | |
129 | * @clone_flags: flags | |
130 | * @usp: user stack pointer or fn for kernel thread | |
131 | * @arg: arg to fn for kernel thread; always NULL for userspace thread | |
132 | * @p: the newly created task | |
133 | * @regs: CPU context to copy for userspace thread; always NULL for kthread | |
134 | * | |
135 | * At the top of a newly initialized kernel stack are two stacked pt_reg | |
136 | * structures. The first (topmost) is the userspace context of the thread. | |
137 | * The second is the kernelspace context of the thread. | |
138 | * | |
139 | * A kernel thread will not be returning to userspace, so the topmost pt_regs | |
140 | * struct can be uninitialized; it _does_ need to exist, though, because | |
141 | * a kernel thread can become a userspace thread by doing a kernel_execve, in | |
142 | * which case the topmost context will be initialized and used for 'returning' | |
143 | * to userspace. | |
144 | * | |
145 | * The second pt_reg struct needs to be initialized to 'return' to | |
146 | * ret_from_fork. A kernel thread will need to set r20 to the address of | |
147 | * a function to call into (with arg in r22); userspace threads need to set | |
148 | * r20 to NULL in which case ret_from_fork will just continue a return to | |
149 | * userspace. | |
150 | * | |
151 | * A kernel thread 'fn' may return; this is effectively what happens when | |
152 | * kernel_execve is called. In that case, the userspace pt_regs must have | |
153 | * been initialized (which kernel_execve takes care of, see start_thread | |
154 | * below); ret_from_fork will then continue its execution causing the | |
155 | * 'kernel thread' to return to userspace as a userspace thread. | |
156 | */ | |
157 | ||
88ef7f3f JB |
158 | int |
159 | copy_thread(unsigned long clone_flags, unsigned long usp, | |
afa86fc4 | 160 | unsigned long arg, struct task_struct *p) |
88ef7f3f | 161 | { |
cbf23cf1 | 162 | struct pt_regs *userregs; |
88ef7f3f JB |
163 | struct pt_regs *kregs; |
164 | unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; | |
88ef7f3f JB |
165 | unsigned long top_of_kernel_stack; |
166 | ||
167 | top_of_kernel_stack = sp; | |
168 | ||
169 | p->set_child_tid = p->clear_child_tid = NULL; | |
170 | ||
cbf23cf1 JB |
171 | /* Locate userspace context on stack... */ |
172 | sp -= STACK_FRAME_OVERHEAD; /* redzone */ | |
88ef7f3f | 173 | sp -= sizeof(struct pt_regs); |
cbf23cf1 | 174 | userregs = (struct pt_regs *) sp; |
88ef7f3f | 175 | |
cbf23cf1 JB |
176 | /* ...and kernel context */ |
177 | sp -= STACK_FRAME_OVERHEAD; /* redzone */ | |
178 | sp -= sizeof(struct pt_regs); | |
179 | kregs = (struct pt_regs *)sp; | |
88ef7f3f | 180 | |
cbf23cf1 JB |
181 | if (unlikely(p->flags & PF_KTHREAD)) { |
182 | memset(kregs, 0, sizeof(struct pt_regs)); | |
183 | kregs->gpr[20] = usp; /* fn, kernel thread */ | |
184 | kregs->gpr[22] = arg; | |
88ef7f3f | 185 | } else { |
39d91a9e | 186 | *userregs = *current_pt_regs(); |
88ef7f3f | 187 | |
39d91a9e AV |
188 | if (usp) |
189 | userregs->sp = usp; | |
e60aa2fb CS |
190 | |
191 | /* | |
192 | * For CLONE_SETTLS set "tp" (r10) to the TLS pointer passed to sys_clone. | |
193 | * | |
194 | * The kernel entry is: | |
195 | * int clone (long flags, void *child_stack, int *parent_tid, | |
196 | * int *child_tid, struct void *tls) | |
197 | * | |
198 | * This makes the source r7 in the kernel registers. | |
199 | */ | |
200 | if (clone_flags & CLONE_SETTLS) | |
201 | userregs->gpr[10] = userregs->gpr[7]; | |
202 | ||
cbf23cf1 | 203 | userregs->gpr[11] = 0; /* Result from fork() */ |
88ef7f3f | 204 | |
cbf23cf1 JB |
205 | kregs->gpr[20] = 0; /* Userspace thread */ |
206 | } | |
88ef7f3f | 207 | |
cbf23cf1 JB |
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. | |
88ef7f3f JB |
211 | */ |
212 | kregs->sp = top_of_kernel_stack; | |
88ef7f3f JB |
213 | kregs->gpr[9] = (unsigned long)ret_from_fork; |
214 | ||
cbf23cf1 JB |
215 | task_thread_info(p)->ksp = (unsigned long)kregs; |
216 | ||
88ef7f3f JB |
217 | return 0; |
218 | } | |
219 | ||
220 | /* | |
221 | * Set up a thread for executing a new program | |
222 | */ | |
223 | void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) | |
224 | { | |
cbf23cf1 | 225 | unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM; |
88ef7f3f | 226 | |
cbf23cf1 | 227 | memset(regs, 0, sizeof(struct pt_regs)); |
88ef7f3f JB |
228 | |
229 | regs->pc = pc; | |
230 | regs->sr = sr; | |
231 | regs->sp = sp; | |
88ef7f3f JB |
232 | } |
233 | ||
234 | /* Fill in the fpu structure for a core dump. */ | |
235 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu) | |
236 | { | |
237 | /* TODO */ | |
238 | return 0; | |
239 | } | |
240 | ||
241 | extern struct thread_info *_switch(struct thread_info *old_ti, | |
242 | struct thread_info *new_ti); | |
63104c06 | 243 | extern int lwa_flag; |
88ef7f3f JB |
244 | |
245 | struct task_struct *__switch_to(struct task_struct *old, | |
246 | struct task_struct *new) | |
247 | { | |
248 | struct task_struct *last; | |
249 | struct thread_info *new_ti, *old_ti; | |
250 | unsigned long flags; | |
251 | ||
252 | local_irq_save(flags); | |
253 | ||
254 | /* current_set is an array of saved current pointers | |
255 | * (one for each cpu). we need them at user->kernel transition, | |
256 | * while we save them at kernel->user transition | |
257 | */ | |
258 | new_ti = new->stack; | |
259 | old_ti = old->stack; | |
260 | ||
63104c06 SK |
261 | lwa_flag = 0; |
262 | ||
88ef7f3f JB |
263 | current_thread_info_set[smp_processor_id()] = new_ti; |
264 | last = (_switch(old_ti, new_ti))->task; | |
265 | ||
266 | local_irq_restore(flags); | |
267 | ||
268 | return last; | |
269 | } | |
270 | ||
271 | /* | |
272 | * Write out registers in core dump format, as defined by the | |
273 | * struct user_regs_struct | |
274 | */ | |
275 | void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs) | |
276 | { | |
277 | dest[0] = 0; /* r0 */ | |
278 | memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long)); | |
279 | dest[32] = regs->pc; | |
280 | dest[33] = regs->sr; | |
281 | dest[34] = 0; | |
282 | dest[35] = 0; | |
283 | } | |
284 | ||
88ef7f3f JB |
285 | unsigned long get_wchan(struct task_struct *p) |
286 | { | |
287 | /* TODO */ | |
288 | ||
289 | return 0; | |
290 | } |