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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> | |
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 | ||
7c0f6ba6 | 39 | #include <linux/uaccess.h> |
88ef7f3f | 40 | #include <asm/pgtable.h> |
88ef7f3f JB |
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 | */ | |
52 | struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, }; | |
53 | ||
54 | void 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 | */ | |
65 | void 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. */ | |
72 | void machine_power_off(void) | |
73 | { | |
74 | printk(KERN_INFO "*** MACHINE POWER OFF ***\n"); | |
75 | __asm__("l.nop 1"); | |
76 | } | |
77 | ||
e29d11c6 SM |
78 | /* |
79 | * Send the doze signal to the cpu if available. | |
80 | * Make sure, that all interrupts are enabled | |
81 | */ | |
82 | void arch_cpu_idle(void) | |
83 | { | |
84 | local_irq_enable(); | |
85 | if (mfspr(SPR_UPR) & SPR_UPR_PMP) | |
86 | mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME); | |
87 | } | |
88 | ||
88ef7f3f JB |
89 | void (*pm_power_off) (void) = machine_power_off; |
90 | ||
91 | /* | |
92 | * When a process does an "exec", machine state like FPU and debug | |
93 | * registers need to be reset. This is a hook function for that. | |
94 | * Currently we don't have any such state to reset, so this is empty. | |
95 | */ | |
96 | void flush_thread(void) | |
97 | { | |
98 | } | |
99 | ||
100 | void show_regs(struct pt_regs *regs) | |
101 | { | |
102 | extern void show_registers(struct pt_regs *regs); | |
103 | ||
a43cb95d | 104 | show_regs_print_info(KERN_DEFAULT); |
88ef7f3f JB |
105 | /* __PHX__ cleanup this mess */ |
106 | show_registers(regs); | |
107 | } | |
108 | ||
109 | unsigned long thread_saved_pc(struct task_struct *t) | |
110 | { | |
111 | return (unsigned long)user_regs(t->stack)->pc; | |
112 | } | |
113 | ||
114 | void release_thread(struct task_struct *dead_task) | |
115 | { | |
116 | } | |
117 | ||
118 | /* | |
119 | * Copy the thread-specific (arch specific) info from the current | |
120 | * process to the new one p | |
121 | */ | |
122 | extern asmlinkage void ret_from_fork(void); | |
123 | ||
cbf23cf1 JB |
124 | /* |
125 | * copy_thread | |
126 | * @clone_flags: flags | |
127 | * @usp: user stack pointer or fn for kernel thread | |
128 | * @arg: arg to fn for kernel thread; always NULL for userspace thread | |
129 | * @p: the newly created task | |
130 | * @regs: CPU context to copy for userspace thread; always NULL for kthread | |
131 | * | |
132 | * At the top of a newly initialized kernel stack are two stacked pt_reg | |
133 | * structures. The first (topmost) is the userspace context of the thread. | |
134 | * The second is the kernelspace context of the thread. | |
135 | * | |
136 | * A kernel thread will not be returning to userspace, so the topmost pt_regs | |
137 | * struct can be uninitialized; it _does_ need to exist, though, because | |
138 | * a kernel thread can become a userspace thread by doing a kernel_execve, in | |
139 | * which case the topmost context will be initialized and used for 'returning' | |
140 | * to userspace. | |
141 | * | |
142 | * The second pt_reg struct needs to be initialized to 'return' to | |
143 | * ret_from_fork. A kernel thread will need to set r20 to the address of | |
144 | * a function to call into (with arg in r22); userspace threads need to set | |
145 | * r20 to NULL in which case ret_from_fork will just continue a return to | |
146 | * userspace. | |
147 | * | |
148 | * A kernel thread 'fn' may return; this is effectively what happens when | |
149 | * kernel_execve is called. In that case, the userspace pt_regs must have | |
150 | * been initialized (which kernel_execve takes care of, see start_thread | |
151 | * below); ret_from_fork will then continue its execution causing the | |
152 | * 'kernel thread' to return to userspace as a userspace thread. | |
153 | */ | |
154 | ||
88ef7f3f JB |
155 | int |
156 | copy_thread(unsigned long clone_flags, unsigned long usp, | |
afa86fc4 | 157 | unsigned long arg, struct task_struct *p) |
88ef7f3f | 158 | { |
cbf23cf1 | 159 | struct pt_regs *userregs; |
88ef7f3f JB |
160 | struct pt_regs *kregs; |
161 | unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; | |
88ef7f3f JB |
162 | unsigned long top_of_kernel_stack; |
163 | ||
164 | top_of_kernel_stack = sp; | |
165 | ||
166 | p->set_child_tid = p->clear_child_tid = NULL; | |
167 | ||
cbf23cf1 JB |
168 | /* Locate userspace context on stack... */ |
169 | sp -= STACK_FRAME_OVERHEAD; /* redzone */ | |
88ef7f3f | 170 | sp -= sizeof(struct pt_regs); |
cbf23cf1 | 171 | userregs = (struct pt_regs *) sp; |
88ef7f3f | 172 | |
cbf23cf1 JB |
173 | /* ...and kernel context */ |
174 | sp -= STACK_FRAME_OVERHEAD; /* redzone */ | |
175 | sp -= sizeof(struct pt_regs); | |
176 | kregs = (struct pt_regs *)sp; | |
88ef7f3f | 177 | |
cbf23cf1 JB |
178 | if (unlikely(p->flags & PF_KTHREAD)) { |
179 | memset(kregs, 0, sizeof(struct pt_regs)); | |
180 | kregs->gpr[20] = usp; /* fn, kernel thread */ | |
181 | kregs->gpr[22] = arg; | |
88ef7f3f | 182 | } else { |
39d91a9e | 183 | *userregs = *current_pt_regs(); |
88ef7f3f | 184 | |
39d91a9e AV |
185 | if (usp) |
186 | userregs->sp = usp; | |
e60aa2fb CS |
187 | |
188 | /* | |
189 | * For CLONE_SETTLS set "tp" (r10) to the TLS pointer passed to sys_clone. | |
190 | * | |
191 | * The kernel entry is: | |
192 | * int clone (long flags, void *child_stack, int *parent_tid, | |
193 | * int *child_tid, struct void *tls) | |
194 | * | |
195 | * This makes the source r7 in the kernel registers. | |
196 | */ | |
197 | if (clone_flags & CLONE_SETTLS) | |
198 | userregs->gpr[10] = userregs->gpr[7]; | |
199 | ||
cbf23cf1 | 200 | userregs->gpr[11] = 0; /* Result from fork() */ |
88ef7f3f | 201 | |
cbf23cf1 JB |
202 | kregs->gpr[20] = 0; /* Userspace thread */ |
203 | } | |
88ef7f3f | 204 | |
cbf23cf1 JB |
205 | /* |
206 | * _switch wants the kernel stack page in pt_regs->sp so that it | |
207 | * can restore it to thread_info->ksp... see _switch for details. | |
88ef7f3f JB |
208 | */ |
209 | kregs->sp = top_of_kernel_stack; | |
88ef7f3f JB |
210 | kregs->gpr[9] = (unsigned long)ret_from_fork; |
211 | ||
cbf23cf1 JB |
212 | task_thread_info(p)->ksp = (unsigned long)kregs; |
213 | ||
88ef7f3f JB |
214 | return 0; |
215 | } | |
216 | ||
217 | /* | |
218 | * Set up a thread for executing a new program | |
219 | */ | |
220 | void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) | |
221 | { | |
cbf23cf1 | 222 | unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM; |
88ef7f3f | 223 | |
cbf23cf1 | 224 | memset(regs, 0, sizeof(struct pt_regs)); |
88ef7f3f JB |
225 | |
226 | regs->pc = pc; | |
227 | regs->sr = sr; | |
228 | regs->sp = sp; | |
88ef7f3f JB |
229 | } |
230 | ||
231 | /* Fill in the fpu structure for a core dump. */ | |
232 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu) | |
233 | { | |
234 | /* TODO */ | |
235 | return 0; | |
236 | } | |
237 | ||
238 | extern struct thread_info *_switch(struct thread_info *old_ti, | |
239 | struct thread_info *new_ti); | |
63104c06 | 240 | extern int lwa_flag; |
88ef7f3f JB |
241 | |
242 | struct task_struct *__switch_to(struct task_struct *old, | |
243 | struct task_struct *new) | |
244 | { | |
245 | struct task_struct *last; | |
246 | struct thread_info *new_ti, *old_ti; | |
247 | unsigned long flags; | |
248 | ||
249 | local_irq_save(flags); | |
250 | ||
251 | /* current_set is an array of saved current pointers | |
252 | * (one for each cpu). we need them at user->kernel transition, | |
253 | * while we save them at kernel->user transition | |
254 | */ | |
255 | new_ti = new->stack; | |
256 | old_ti = old->stack; | |
257 | ||
63104c06 SK |
258 | lwa_flag = 0; |
259 | ||
88ef7f3f JB |
260 | current_thread_info_set[smp_processor_id()] = new_ti; |
261 | last = (_switch(old_ti, new_ti))->task; | |
262 | ||
263 | local_irq_restore(flags); | |
264 | ||
265 | return last; | |
266 | } | |
267 | ||
268 | /* | |
269 | * Write out registers in core dump format, as defined by the | |
270 | * struct user_regs_struct | |
271 | */ | |
272 | void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs) | |
273 | { | |
274 | dest[0] = 0; /* r0 */ | |
275 | memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long)); | |
276 | dest[32] = regs->pc; | |
277 | dest[33] = regs->sr; | |
278 | dest[34] = 0; | |
279 | dest[35] = 0; | |
280 | } | |
281 | ||
88ef7f3f JB |
282 | unsigned long get_wchan(struct task_struct *p) |
283 | { | |
284 | /* TODO */ | |
285 | ||
286 | return 0; | |
287 | } |