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Commit | Line | Data |
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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. | |
40ac5d47 | 7 | * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org) |
1da177e4 LT |
8 | * Copyright (C) 1999, 2000 Silicon Graphics, Inc. |
9 | * Copyright (C) 2004 Thiemo Seufer | |
10 | */ | |
1da177e4 LT |
11 | #include <linux/errno.h> |
12 | #include <linux/module.h> | |
13 | #include <linux/sched.h> | |
7bcf7717 | 14 | #include <linux/tick.h> |
1da177e4 LT |
15 | #include <linux/kernel.h> |
16 | #include <linux/mm.h> | |
17 | #include <linux/stddef.h> | |
18 | #include <linux/unistd.h> | |
19 | #include <linux/ptrace.h> | |
20 | #include <linux/slab.h> | |
21 | #include <linux/mman.h> | |
22 | #include <linux/personality.h> | |
23 | #include <linux/sys.h> | |
24 | #include <linux/user.h> | |
1da177e4 LT |
25 | #include <linux/init.h> |
26 | #include <linux/completion.h> | |
63077519 | 27 | #include <linux/kallsyms.h> |
94109102 | 28 | #include <linux/random.h> |
1da177e4 | 29 | |
94109102 | 30 | #include <asm/asm.h> |
1da177e4 LT |
31 | #include <asm/bootinfo.h> |
32 | #include <asm/cpu.h> | |
e50c0a8f | 33 | #include <asm/dsp.h> |
1da177e4 LT |
34 | #include <asm/fpu.h> |
35 | #include <asm/pgtable.h> | |
36 | #include <asm/system.h> | |
37 | #include <asm/mipsregs.h> | |
38 | #include <asm/processor.h> | |
39 | #include <asm/uaccess.h> | |
40 | #include <asm/io.h> | |
41 | #include <asm/elf.h> | |
42 | #include <asm/isadep.h> | |
43 | #include <asm/inst.h> | |
1df0f0ff | 44 | #include <asm/stacktrace.h> |
1da177e4 | 45 | |
1da177e4 LT |
46 | /* |
47 | * The idle thread. There's no useful work to be done, so just try to conserve | |
48 | * power and have a low exit latency (ie sit in a loop waiting for somebody to | |
49 | * say that they'd like to reschedule) | |
50 | */ | |
b3f6df9f | 51 | void __noreturn cpu_idle(void) |
1da177e4 LT |
52 | { |
53 | /* endless idle loop with no priority at all */ | |
54 | while (1) { | |
b8f8c3cf | 55 | tick_nohz_stop_sched_tick(1); |
41c594ab | 56 | while (!need_resched()) { |
9cc12363 | 57 | #ifdef CONFIG_MIPS_MT_SMTC |
447deafb RB |
58 | extern void smtc_idle_loop_hook(void); |
59 | ||
41c594ab | 60 | smtc_idle_loop_hook(); |
c68644d3 | 61 | #endif |
1da177e4 LT |
62 | if (cpu_wait) |
63 | (*cpu_wait)(); | |
41c594ab | 64 | } |
7bcf7717 | 65 | tick_nohz_restart_sched_tick(); |
5bfb5d69 | 66 | preempt_enable_no_resched(); |
1da177e4 | 67 | schedule(); |
5bfb5d69 | 68 | preempt_disable(); |
1da177e4 LT |
69 | } |
70 | } | |
71 | ||
72 | asmlinkage void ret_from_fork(void); | |
73 | ||
74 | void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) | |
75 | { | |
76 | unsigned long status; | |
77 | ||
78 | /* New thread loses kernel privileges. */ | |
bbaf238b | 79 | status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK); |
875d43e7 | 80 | #ifdef CONFIG_64BIT |
293c5bd1 | 81 | status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR; |
1da177e4 LT |
82 | #endif |
83 | status |= KU_USER; | |
84 | regs->cp0_status = status; | |
85 | clear_used_math(); | |
e04582b7 | 86 | clear_fpu_owner(); |
e50c0a8f RB |
87 | if (cpu_has_dsp) |
88 | __init_dsp(); | |
1da177e4 LT |
89 | regs->cp0_epc = pc; |
90 | regs->regs[29] = sp; | |
91 | current_thread_info()->addr_limit = USER_DS; | |
92 | } | |
93 | ||
94 | void exit_thread(void) | |
95 | { | |
96 | } | |
97 | ||
98 | void flush_thread(void) | |
99 | { | |
100 | } | |
101 | ||
102 | int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, | |
103 | unsigned long unused, struct task_struct *p, struct pt_regs *regs) | |
104 | { | |
75bb07e7 | 105 | struct thread_info *ti = task_thread_info(p); |
1da177e4 LT |
106 | struct pt_regs *childregs; |
107 | long childksp; | |
3c37026d | 108 | p->set_child_tid = p->clear_child_tid = NULL; |
1da177e4 | 109 | |
75bb07e7 | 110 | childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; |
1da177e4 LT |
111 | |
112 | preempt_disable(); | |
113 | ||
e50c0a8f | 114 | if (is_fpu_owner()) |
1da177e4 | 115 | save_fp(p); |
e50c0a8f RB |
116 | |
117 | if (cpu_has_dsp) | |
118 | save_dsp(p); | |
1da177e4 LT |
119 | |
120 | preempt_enable(); | |
121 | ||
122 | /* set up new TSS. */ | |
123 | childregs = (struct pt_regs *) childksp - 1; | |
124 | *childregs = *regs; | |
125 | childregs->regs[7] = 0; /* Clear error flag */ | |
126 | ||
1da177e4 LT |
127 | childregs->regs[2] = 0; /* Child gets zero as return value */ |
128 | regs->regs[2] = p->pid; | |
129 | ||
130 | if (childregs->cp0_status & ST0_CU0) { | |
131 | childregs->regs[28] = (unsigned long) ti; | |
132 | childregs->regs[29] = childksp; | |
133 | ti->addr_limit = KERNEL_DS; | |
134 | } else { | |
135 | childregs->regs[29] = usp; | |
136 | ti->addr_limit = USER_DS; | |
137 | } | |
138 | p->thread.reg29 = (unsigned long) childregs; | |
139 | p->thread.reg31 = (unsigned long) ret_from_fork; | |
140 | ||
141 | /* | |
142 | * New tasks lose permission to use the fpu. This accelerates context | |
143 | * switching for most programs since they don't use the fpu. | |
144 | */ | |
145 | p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); | |
146 | childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); | |
1da177e4 | 147 | |
9cc12363 | 148 | #ifdef CONFIG_MIPS_MT_SMTC |
f088fc84 | 149 | /* |
9cc12363 KK |
150 | * SMTC restores TCStatus after Status, and the CU bits |
151 | * are aliased there. | |
f088fc84 | 152 | */ |
9cc12363 KK |
153 | childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1); |
154 | #endif | |
1da177e4 LT |
155 | clear_tsk_thread_flag(p, TIF_USEDFPU); |
156 | ||
f088fc84 | 157 | #ifdef CONFIG_MIPS_MT_FPAFF |
6657fe0a | 158 | clear_tsk_thread_flag(p, TIF_FPUBOUND); |
f088fc84 RB |
159 | #endif /* CONFIG_MIPS_MT_FPAFF */ |
160 | ||
3c37026d RB |
161 | if (clone_flags & CLONE_SETTLS) |
162 | ti->tp_value = regs->regs[7]; | |
163 | ||
1da177e4 LT |
164 | return 0; |
165 | } | |
166 | ||
167 | /* Fill in the fpu structure for a core dump.. */ | |
168 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) | |
169 | { | |
170 | memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu)); | |
171 | ||
172 | return 1; | |
173 | } | |
174 | ||
d56efda4 | 175 | void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs) |
1da177e4 LT |
176 | { |
177 | int i; | |
178 | ||
179 | for (i = 0; i < EF_R0; i++) | |
180 | gp[i] = 0; | |
181 | gp[EF_R0] = 0; | |
182 | for (i = 1; i <= 31; i++) | |
183 | gp[EF_R0 + i] = regs->regs[i]; | |
184 | gp[EF_R26] = 0; | |
185 | gp[EF_R27] = 0; | |
186 | gp[EF_LO] = regs->lo; | |
187 | gp[EF_HI] = regs->hi; | |
188 | gp[EF_CP0_EPC] = regs->cp0_epc; | |
189 | gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; | |
190 | gp[EF_CP0_STATUS] = regs->cp0_status; | |
191 | gp[EF_CP0_CAUSE] = regs->cp0_cause; | |
192 | #ifdef EF_UNUSED0 | |
193 | gp[EF_UNUSED0] = 0; | |
194 | #endif | |
195 | } | |
196 | ||
49a89efb | 197 | int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) |
71e0e556 | 198 | { |
40bc9c67 | 199 | elf_dump_regs(*regs, task_pt_regs(tsk)); |
71e0e556 RB |
200 | return 1; |
201 | } | |
202 | ||
49a89efb | 203 | int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) |
1da177e4 LT |
204 | { |
205 | memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu)); | |
206 | ||
207 | return 1; | |
208 | } | |
209 | ||
210 | /* | |
211 | * Create a kernel thread | |
212 | */ | |
b3f6df9f | 213 | static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *)) |
1da177e4 LT |
214 | { |
215 | do_exit(fn(arg)); | |
216 | } | |
217 | ||
218 | long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
219 | { | |
220 | struct pt_regs regs; | |
221 | ||
222 | memset(®s, 0, sizeof(regs)); | |
223 | ||
224 | regs.regs[4] = (unsigned long) arg; | |
225 | regs.regs[5] = (unsigned long) fn; | |
226 | regs.cp0_epc = (unsigned long) kernel_thread_helper; | |
227 | regs.cp0_status = read_c0_status(); | |
228 | #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) | |
e5d77754 MR |
229 | regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | |
230 | ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2); | |
1da177e4 LT |
231 | #else |
232 | regs.cp0_status |= ST0_EXL; | |
233 | #endif | |
234 | ||
235 | /* Ok, create the new process.. */ | |
236 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); | |
237 | } | |
238 | ||
b5943182 FBH |
239 | /* |
240 | * | |
241 | */ | |
242 | struct mips_frame_info { | |
243 | void *func; | |
244 | unsigned long func_size; | |
245 | int frame_size; | |
246 | int pc_offset; | |
247 | }; | |
dc953df1 | 248 | |
c0efbb6d FBH |
249 | static inline int is_ra_save_ins(union mips_instruction *ip) |
250 | { | |
251 | /* sw / sd $ra, offset($sp) */ | |
252 | return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && | |
253 | ip->i_format.rs == 29 && | |
254 | ip->i_format.rt == 31; | |
255 | } | |
256 | ||
257 | static inline int is_jal_jalr_jr_ins(union mips_instruction *ip) | |
258 | { | |
259 | if (ip->j_format.opcode == jal_op) | |
260 | return 1; | |
261 | if (ip->r_format.opcode != spec_op) | |
262 | return 0; | |
263 | return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; | |
264 | } | |
265 | ||
266 | static inline int is_sp_move_ins(union mips_instruction *ip) | |
267 | { | |
268 | /* addiu/daddiu sp,sp,-imm */ | |
269 | if (ip->i_format.rs != 29 || ip->i_format.rt != 29) | |
270 | return 0; | |
271 | if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) | |
272 | return 1; | |
273 | return 0; | |
274 | } | |
275 | ||
f66686f7 | 276 | static int get_frame_info(struct mips_frame_info *info) |
1da177e4 | 277 | { |
c0efbb6d | 278 | union mips_instruction *ip = info->func; |
29b376ff FBH |
279 | unsigned max_insns = info->func_size / sizeof(union mips_instruction); |
280 | unsigned i; | |
c0efbb6d | 281 | |
1da177e4 | 282 | info->pc_offset = -1; |
63077519 | 283 | info->frame_size = 0; |
1da177e4 | 284 | |
29b376ff FBH |
285 | if (!ip) |
286 | goto err; | |
287 | ||
288 | if (max_insns == 0) | |
289 | max_insns = 128U; /* unknown function size */ | |
290 | max_insns = min(128U, max_insns); | |
291 | ||
c0efbb6d FBH |
292 | for (i = 0; i < max_insns; i++, ip++) { |
293 | ||
294 | if (is_jal_jalr_jr_ins(ip)) | |
63077519 | 295 | break; |
0cceb4aa FBH |
296 | if (!info->frame_size) { |
297 | if (is_sp_move_ins(ip)) | |
298 | info->frame_size = - ip->i_format.simmediate; | |
299 | continue; | |
63077519 | 300 | } |
0cceb4aa | 301 | if (info->pc_offset == -1 && is_ra_save_ins(ip)) { |
63077519 AN |
302 | info->pc_offset = |
303 | ip->i_format.simmediate / sizeof(long); | |
0cceb4aa | 304 | break; |
1da177e4 LT |
305 | } |
306 | } | |
f66686f7 AN |
307 | if (info->frame_size && info->pc_offset >= 0) /* nested */ |
308 | return 0; | |
309 | if (info->pc_offset < 0) /* leaf */ | |
310 | return 1; | |
311 | /* prologue seems boggus... */ | |
29b376ff | 312 | err: |
f66686f7 | 313 | return -1; |
1da177e4 LT |
314 | } |
315 | ||
b5943182 FBH |
316 | static struct mips_frame_info schedule_mfi __read_mostly; |
317 | ||
1da177e4 LT |
318 | static int __init frame_info_init(void) |
319 | { | |
b5943182 | 320 | unsigned long size = 0; |
63077519 | 321 | #ifdef CONFIG_KALLSYMS |
b5943182 | 322 | unsigned long ofs; |
b5943182 | 323 | |
55b74283 | 324 | kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs); |
63077519 | 325 | #endif |
b5943182 FBH |
326 | schedule_mfi.func = schedule; |
327 | schedule_mfi.func_size = size; | |
328 | ||
329 | get_frame_info(&schedule_mfi); | |
6057a798 FBH |
330 | |
331 | /* | |
332 | * Without schedule() frame info, result given by | |
333 | * thread_saved_pc() and get_wchan() are not reliable. | |
334 | */ | |
b5943182 | 335 | if (schedule_mfi.pc_offset < 0) |
6057a798 | 336 | printk("Can't analyze schedule() prologue at %p\n", schedule); |
63077519 | 337 | |
1da177e4 LT |
338 | return 0; |
339 | } | |
340 | ||
341 | arch_initcall(frame_info_init); | |
342 | ||
343 | /* | |
344 | * Return saved PC of a blocked thread. | |
345 | */ | |
346 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
347 | { | |
348 | struct thread_struct *t = &tsk->thread; | |
349 | ||
350 | /* New born processes are a special case */ | |
351 | if (t->reg31 == (unsigned long) ret_from_fork) | |
352 | return t->reg31; | |
b5943182 | 353 | if (schedule_mfi.pc_offset < 0) |
1da177e4 | 354 | return 0; |
b5943182 | 355 | return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; |
1da177e4 LT |
356 | } |
357 | ||
1da177e4 | 358 | |
f66686f7 | 359 | #ifdef CONFIG_KALLSYMS |
4d157d5e FBH |
360 | /* used by show_backtrace() */ |
361 | unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, | |
1924600c | 362 | unsigned long pc, unsigned long *ra) |
f66686f7 AN |
363 | { |
364 | unsigned long stack_page; | |
365 | struct mips_frame_info info; | |
f66686f7 | 366 | unsigned long size, ofs; |
4d157d5e | 367 | int leaf; |
1924600c AN |
368 | extern void ret_from_irq(void); |
369 | extern void ret_from_exception(void); | |
f66686f7 AN |
370 | |
371 | stack_page = (unsigned long)task_stack_page(task); | |
372 | if (!stack_page) | |
373 | return 0; | |
374 | ||
1924600c AN |
375 | /* |
376 | * If we reached the bottom of interrupt context, | |
377 | * return saved pc in pt_regs. | |
378 | */ | |
379 | if (pc == (unsigned long)ret_from_irq || | |
380 | pc == (unsigned long)ret_from_exception) { | |
381 | struct pt_regs *regs; | |
382 | if (*sp >= stack_page && | |
383 | *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) { | |
384 | regs = (struct pt_regs *)*sp; | |
385 | pc = regs->cp0_epc; | |
386 | if (__kernel_text_address(pc)) { | |
387 | *sp = regs->regs[29]; | |
388 | *ra = regs->regs[31]; | |
389 | return pc; | |
390 | } | |
391 | } | |
392 | return 0; | |
393 | } | |
55b74283 | 394 | if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) |
f66686f7 | 395 | return 0; |
1fd69098 FBH |
396 | /* |
397 | * Return ra if an exception occured at the first instruction | |
398 | */ | |
1924600c AN |
399 | if (unlikely(ofs == 0)) { |
400 | pc = *ra; | |
401 | *ra = 0; | |
402 | return pc; | |
403 | } | |
f66686f7 AN |
404 | |
405 | info.func = (void *)(pc - ofs); | |
406 | info.func_size = ofs; /* analyze from start to ofs */ | |
4d157d5e FBH |
407 | leaf = get_frame_info(&info); |
408 | if (leaf < 0) | |
f66686f7 | 409 | return 0; |
4d157d5e FBH |
410 | |
411 | if (*sp < stack_page || | |
412 | *sp + info.frame_size > stack_page + THREAD_SIZE - 32) | |
f66686f7 AN |
413 | return 0; |
414 | ||
4d157d5e FBH |
415 | if (leaf) |
416 | /* | |
417 | * For some extreme cases, get_frame_info() can | |
418 | * consider wrongly a nested function as a leaf | |
419 | * one. In that cases avoid to return always the | |
420 | * same value. | |
421 | */ | |
1924600c | 422 | pc = pc != *ra ? *ra : 0; |
4d157d5e FBH |
423 | else |
424 | pc = ((unsigned long *)(*sp))[info.pc_offset]; | |
425 | ||
426 | *sp += info.frame_size; | |
1924600c | 427 | *ra = 0; |
4d157d5e | 428 | return __kernel_text_address(pc) ? pc : 0; |
f66686f7 AN |
429 | } |
430 | #endif | |
b5943182 FBH |
431 | |
432 | /* | |
433 | * get_wchan - a maintenance nightmare^W^Wpain in the ass ... | |
434 | */ | |
435 | unsigned long get_wchan(struct task_struct *task) | |
436 | { | |
437 | unsigned long pc = 0; | |
438 | #ifdef CONFIG_KALLSYMS | |
439 | unsigned long sp; | |
1924600c | 440 | unsigned long ra = 0; |
b5943182 FBH |
441 | #endif |
442 | ||
443 | if (!task || task == current || task->state == TASK_RUNNING) | |
444 | goto out; | |
445 | if (!task_stack_page(task)) | |
446 | goto out; | |
447 | ||
448 | pc = thread_saved_pc(task); | |
449 | ||
450 | #ifdef CONFIG_KALLSYMS | |
451 | sp = task->thread.reg29 + schedule_mfi.frame_size; | |
452 | ||
453 | while (in_sched_functions(pc)) | |
1924600c | 454 | pc = unwind_stack(task, &sp, pc, &ra); |
b5943182 FBH |
455 | #endif |
456 | ||
457 | out: | |
458 | return pc; | |
459 | } | |
94109102 FBH |
460 | |
461 | /* | |
462 | * Don't forget that the stack pointer must be aligned on a 8 bytes | |
463 | * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. | |
464 | */ | |
465 | unsigned long arch_align_stack(unsigned long sp) | |
466 | { | |
467 | if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) | |
468 | sp -= get_random_int() & ~PAGE_MASK; | |
469 | ||
470 | return sp & ALMASK; | |
471 | } |