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1da177e4 LT |
1 | /* |
2 | * This file is subject to the terms and conditions of the GNU General Public | |
3 | * License. See the file "COPYING" in the main directory of this archive | |
4 | * for more details. | |
5 | * | |
6 | * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others. | |
7 | * Copyright (C) 1999, 2000 Silicon Graphics, Inc. | |
8 | * Copyright (C) 2004 Thiemo Seufer | |
9 | */ | |
10 | #include <linux/config.h> | |
11 | #include <linux/errno.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/stddef.h> | |
17 | #include <linux/unistd.h> | |
18 | #include <linux/ptrace.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/mman.h> | |
21 | #include <linux/personality.h> | |
22 | #include <linux/sys.h> | |
23 | #include <linux/user.h> | |
24 | #include <linux/a.out.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/completion.h> | |
27 | ||
28 | #include <asm/bootinfo.h> | |
29 | #include <asm/cpu.h> | |
30 | #include <asm/fpu.h> | |
31 | #include <asm/pgtable.h> | |
32 | #include <asm/system.h> | |
33 | #include <asm/mipsregs.h> | |
34 | #include <asm/processor.h> | |
35 | #include <asm/uaccess.h> | |
36 | #include <asm/io.h> | |
37 | #include <asm/elf.h> | |
38 | #include <asm/isadep.h> | |
39 | #include <asm/inst.h> | |
40 | ||
41 | /* | |
42 | * We use this if we don't have any better idle routine.. | |
43 | * (This to kill: kernel/platform.c. | |
44 | */ | |
45 | void default_idle (void) | |
46 | { | |
47 | } | |
48 | ||
49 | /* | |
50 | * The idle thread. There's no useful work to be done, so just try to conserve | |
51 | * power and have a low exit latency (ie sit in a loop waiting for somebody to | |
52 | * say that they'd like to reschedule) | |
53 | */ | |
54 | ATTRIB_NORET void cpu_idle(void) | |
55 | { | |
56 | /* endless idle loop with no priority at all */ | |
57 | while (1) { | |
58 | while (!need_resched()) | |
59 | if (cpu_wait) | |
60 | (*cpu_wait)(); | |
61 | schedule(); | |
62 | } | |
63 | } | |
64 | ||
65 | asmlinkage void ret_from_fork(void); | |
66 | ||
67 | void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) | |
68 | { | |
69 | unsigned long status; | |
70 | ||
71 | /* New thread loses kernel privileges. */ | |
72 | status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|KU_MASK); | |
875d43e7 | 73 | #ifdef CONFIG_64BIT |
1da177e4 LT |
74 | status &= ~ST0_FR; |
75 | status |= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR; | |
76 | #endif | |
77 | status |= KU_USER; | |
78 | regs->cp0_status = status; | |
79 | clear_used_math(); | |
80 | lose_fpu(); | |
81 | regs->cp0_epc = pc; | |
82 | regs->regs[29] = sp; | |
83 | current_thread_info()->addr_limit = USER_DS; | |
84 | } | |
85 | ||
86 | void exit_thread(void) | |
87 | { | |
88 | } | |
89 | ||
90 | void flush_thread(void) | |
91 | { | |
92 | } | |
93 | ||
94 | int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, | |
95 | unsigned long unused, struct task_struct *p, struct pt_regs *regs) | |
96 | { | |
97 | struct thread_info *ti = p->thread_info; | |
98 | struct pt_regs *childregs; | |
99 | long childksp; | |
100 | ||
101 | childksp = (unsigned long)ti + THREAD_SIZE - 32; | |
102 | ||
103 | preempt_disable(); | |
104 | ||
105 | if (is_fpu_owner()) { | |
106 | save_fp(p); | |
107 | } | |
108 | ||
109 | preempt_enable(); | |
110 | ||
111 | /* set up new TSS. */ | |
112 | childregs = (struct pt_regs *) childksp - 1; | |
113 | *childregs = *regs; | |
114 | childregs->regs[7] = 0; /* Clear error flag */ | |
115 | ||
116 | #if defined(CONFIG_BINFMT_IRIX) | |
117 | if (current->personality != PER_LINUX) { | |
118 | /* Under IRIX things are a little different. */ | |
119 | childregs->regs[3] = 1; | |
120 | regs->regs[3] = 0; | |
121 | } | |
122 | #endif | |
123 | childregs->regs[2] = 0; /* Child gets zero as return value */ | |
124 | regs->regs[2] = p->pid; | |
125 | ||
126 | if (childregs->cp0_status & ST0_CU0) { | |
127 | childregs->regs[28] = (unsigned long) ti; | |
128 | childregs->regs[29] = childksp; | |
129 | ti->addr_limit = KERNEL_DS; | |
130 | } else { | |
131 | childregs->regs[29] = usp; | |
132 | ti->addr_limit = USER_DS; | |
133 | } | |
134 | p->thread.reg29 = (unsigned long) childregs; | |
135 | p->thread.reg31 = (unsigned long) ret_from_fork; | |
136 | ||
137 | /* | |
138 | * New tasks lose permission to use the fpu. This accelerates context | |
139 | * switching for most programs since they don't use the fpu. | |
140 | */ | |
141 | p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); | |
142 | childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); | |
143 | clear_tsk_thread_flag(p, TIF_USEDFPU); | |
144 | ||
145 | return 0; | |
146 | } | |
147 | ||
148 | /* Fill in the fpu structure for a core dump.. */ | |
149 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) | |
150 | { | |
151 | memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu)); | |
152 | ||
153 | return 1; | |
154 | } | |
155 | ||
156 | void dump_regs(elf_greg_t *gp, struct pt_regs *regs) | |
157 | { | |
158 | int i; | |
159 | ||
160 | for (i = 0; i < EF_R0; i++) | |
161 | gp[i] = 0; | |
162 | gp[EF_R0] = 0; | |
163 | for (i = 1; i <= 31; i++) | |
164 | gp[EF_R0 + i] = regs->regs[i]; | |
165 | gp[EF_R26] = 0; | |
166 | gp[EF_R27] = 0; | |
167 | gp[EF_LO] = regs->lo; | |
168 | gp[EF_HI] = regs->hi; | |
169 | gp[EF_CP0_EPC] = regs->cp0_epc; | |
170 | gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; | |
171 | gp[EF_CP0_STATUS] = regs->cp0_status; | |
172 | gp[EF_CP0_CAUSE] = regs->cp0_cause; | |
173 | #ifdef EF_UNUSED0 | |
174 | gp[EF_UNUSED0] = 0; | |
175 | #endif | |
176 | } | |
177 | ||
178 | int dump_task_fpu (struct task_struct *t, elf_fpregset_t *fpr) | |
179 | { | |
180 | memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu)); | |
181 | ||
182 | return 1; | |
183 | } | |
184 | ||
185 | /* | |
186 | * Create a kernel thread | |
187 | */ | |
188 | ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *)) | |
189 | { | |
190 | do_exit(fn(arg)); | |
191 | } | |
192 | ||
193 | long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
194 | { | |
195 | struct pt_regs regs; | |
196 | ||
197 | memset(®s, 0, sizeof(regs)); | |
198 | ||
199 | regs.regs[4] = (unsigned long) arg; | |
200 | regs.regs[5] = (unsigned long) fn; | |
201 | regs.cp0_epc = (unsigned long) kernel_thread_helper; | |
202 | regs.cp0_status = read_c0_status(); | |
203 | #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) | |
204 | regs.cp0_status &= ~(ST0_KUP | ST0_IEC); | |
205 | regs.cp0_status |= ST0_IEP; | |
206 | #else | |
207 | regs.cp0_status |= ST0_EXL; | |
208 | #endif | |
209 | ||
210 | /* Ok, create the new process.. */ | |
211 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); | |
212 | } | |
213 | ||
214 | struct mips_frame_info { | |
215 | int frame_offset; | |
216 | int pc_offset; | |
217 | }; | |
218 | static struct mips_frame_info schedule_frame; | |
219 | static struct mips_frame_info schedule_timeout_frame; | |
220 | static struct mips_frame_info sleep_on_frame; | |
221 | static struct mips_frame_info sleep_on_timeout_frame; | |
222 | static struct mips_frame_info wait_for_completion_frame; | |
223 | static int mips_frame_info_initialized; | |
224 | static int __init get_frame_info(struct mips_frame_info *info, void *func) | |
225 | { | |
226 | int i; | |
227 | union mips_instruction *ip = (union mips_instruction *)func; | |
228 | info->pc_offset = -1; | |
229 | info->frame_offset = -1; | |
230 | for (i = 0; i < 128; i++, ip++) { | |
231 | /* if jal, jalr, jr, stop. */ | |
232 | if (ip->j_format.opcode == jal_op || | |
233 | (ip->r_format.opcode == spec_op && | |
234 | (ip->r_format.func == jalr_op || | |
235 | ip->r_format.func == jr_op))) | |
236 | break; | |
237 | ||
238 | if ( | |
875d43e7 | 239 | #ifdef CONFIG_32BIT |
1da177e4 LT |
240 | ip->i_format.opcode == sw_op && |
241 | #endif | |
875d43e7 | 242 | #ifdef CONFIG_64BIT |
1da177e4 LT |
243 | ip->i_format.opcode == sd_op && |
244 | #endif | |
245 | ip->i_format.rs == 29) | |
246 | { | |
247 | /* sw / sd $ra, offset($sp) */ | |
248 | if (ip->i_format.rt == 31) { | |
249 | if (info->pc_offset != -1) | |
250 | break; | |
251 | info->pc_offset = | |
252 | ip->i_format.simmediate / sizeof(long); | |
253 | } | |
254 | /* sw / sd $s8, offset($sp) */ | |
255 | if (ip->i_format.rt == 30) { | |
256 | if (info->frame_offset != -1) | |
257 | break; | |
258 | info->frame_offset = | |
259 | ip->i_format.simmediate / sizeof(long); | |
260 | } | |
261 | } | |
262 | } | |
263 | if (info->pc_offset == -1 || info->frame_offset == -1) { | |
264 | printk("Can't analyze prologue code at %p\n", func); | |
265 | info->pc_offset = -1; | |
266 | info->frame_offset = -1; | |
267 | return -1; | |
268 | } | |
269 | ||
270 | return 0; | |
271 | } | |
272 | ||
273 | static int __init frame_info_init(void) | |
274 | { | |
275 | mips_frame_info_initialized = | |
276 | !get_frame_info(&schedule_frame, schedule) && | |
277 | !get_frame_info(&schedule_timeout_frame, schedule_timeout) && | |
278 | !get_frame_info(&sleep_on_frame, sleep_on) && | |
279 | !get_frame_info(&sleep_on_timeout_frame, sleep_on_timeout) && | |
280 | !get_frame_info(&wait_for_completion_frame, wait_for_completion); | |
281 | ||
282 | return 0; | |
283 | } | |
284 | ||
285 | arch_initcall(frame_info_init); | |
286 | ||
287 | /* | |
288 | * Return saved PC of a blocked thread. | |
289 | */ | |
290 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
291 | { | |
292 | struct thread_struct *t = &tsk->thread; | |
293 | ||
294 | /* New born processes are a special case */ | |
295 | if (t->reg31 == (unsigned long) ret_from_fork) | |
296 | return t->reg31; | |
297 | ||
298 | if (schedule_frame.pc_offset < 0) | |
299 | return 0; | |
300 | return ((unsigned long *)t->reg29)[schedule_frame.pc_offset]; | |
301 | } | |
302 | ||
303 | /* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */ | |
304 | unsigned long get_wchan(struct task_struct *p) | |
305 | { | |
306 | unsigned long frame, pc; | |
307 | ||
308 | if (!p || p == current || p->state == TASK_RUNNING) | |
309 | return 0; | |
310 | ||
311 | if (!mips_frame_info_initialized) | |
312 | return 0; | |
313 | pc = thread_saved_pc(p); | |
314 | if (!in_sched_functions(pc)) | |
315 | goto out; | |
316 | ||
317 | if (pc >= (unsigned long) sleep_on_timeout) | |
318 | goto schedule_timeout_caller; | |
319 | if (pc >= (unsigned long) sleep_on) | |
320 | goto schedule_caller; | |
321 | if (pc >= (unsigned long) interruptible_sleep_on_timeout) | |
322 | goto schedule_timeout_caller; | |
323 | if (pc >= (unsigned long)interruptible_sleep_on) | |
324 | goto schedule_caller; | |
325 | if (pc >= (unsigned long)wait_for_completion) | |
326 | goto schedule_caller; | |
327 | goto schedule_timeout_caller; | |
328 | ||
329 | schedule_caller: | |
330 | frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset]; | |
331 | if (pc >= (unsigned long) sleep_on) | |
332 | pc = ((unsigned long *)frame)[sleep_on_frame.pc_offset]; | |
333 | else | |
334 | pc = ((unsigned long *)frame)[wait_for_completion_frame.pc_offset]; | |
335 | goto out; | |
336 | ||
337 | schedule_timeout_caller: | |
338 | /* | |
339 | * The schedule_timeout frame | |
340 | */ | |
341 | frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset]; | |
342 | ||
343 | /* | |
344 | * frame now points to sleep_on_timeout's frame | |
345 | */ | |
346 | pc = ((unsigned long *)frame)[schedule_timeout_frame.pc_offset]; | |
347 | ||
348 | if (in_sched_functions(pc)) { | |
349 | /* schedule_timeout called by [interruptible_]sleep_on_timeout */ | |
350 | frame = ((unsigned long *)frame)[schedule_timeout_frame.frame_offset]; | |
351 | pc = ((unsigned long *)frame)[sleep_on_timeout_frame.pc_offset]; | |
352 | } | |
353 | ||
354 | out: | |
355 | ||
875d43e7 | 356 | #ifdef CONFIG_64BIT |
1da177e4 LT |
357 | if (current->thread.mflags & MF_32BIT_REGS) /* Kludge for 32-bit ps */ |
358 | pc &= 0xffffffffUL; | |
359 | #endif | |
360 | ||
361 | return pc; | |
362 | } | |
363 | ||
364 | EXPORT_SYMBOL(get_wchan); |