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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 | 11 | #include <linux/errno.h> |
1da177e4 | 12 | #include <linux/sched.h> |
7bcf7717 | 13 | #include <linux/tick.h> |
1da177e4 LT |
14 | #include <linux/kernel.h> |
15 | #include <linux/mm.h> | |
16 | #include <linux/stddef.h> | |
17 | #include <linux/unistd.h> | |
cae39d13 | 18 | #include <linux/export.h> |
1da177e4 | 19 | #include <linux/ptrace.h> |
1da177e4 LT |
20 | #include <linux/mman.h> |
21 | #include <linux/personality.h> | |
22 | #include <linux/sys.h> | |
23 | #include <linux/user.h> | |
1da177e4 LT |
24 | #include <linux/init.h> |
25 | #include <linux/completion.h> | |
63077519 | 26 | #include <linux/kallsyms.h> |
94109102 | 27 | #include <linux/random.h> |
1da177e4 | 28 | |
94109102 | 29 | #include <asm/asm.h> |
1da177e4 LT |
30 | #include <asm/bootinfo.h> |
31 | #include <asm/cpu.h> | |
e50c0a8f | 32 | #include <asm/dsp.h> |
1da177e4 LT |
33 | #include <asm/fpu.h> |
34 | #include <asm/pgtable.h> | |
1da177e4 LT |
35 | #include <asm/mipsregs.h> |
36 | #include <asm/processor.h> | |
37 | #include <asm/uaccess.h> | |
38 | #include <asm/io.h> | |
39 | #include <asm/elf.h> | |
40 | #include <asm/isadep.h> | |
41 | #include <asm/inst.h> | |
1df0f0ff | 42 | #include <asm/stacktrace.h> |
1da177e4 | 43 | |
1da177e4 LT |
44 | /* |
45 | * The idle thread. There's no useful work to be done, so just try to conserve | |
46 | * power and have a low exit latency (ie sit in a loop waiting for somebody to | |
47 | * say that they'd like to reschedule) | |
48 | */ | |
b3f6df9f | 49 | void __noreturn cpu_idle(void) |
1da177e4 | 50 | { |
1b2bc75c RB |
51 | int cpu; |
52 | ||
53 | /* CPU is going idle. */ | |
54 | cpu = smp_processor_id(); | |
55 | ||
1da177e4 LT |
56 | /* endless idle loop with no priority at all */ |
57 | while (1) { | |
1268fbc7 FW |
58 | tick_nohz_idle_enter(); |
59 | rcu_idle_enter(); | |
1b2bc75c | 60 | while (!need_resched() && cpu_online(cpu)) { |
9cc12363 | 61 | #ifdef CONFIG_MIPS_MT_SMTC |
447deafb RB |
62 | extern void smtc_idle_loop_hook(void); |
63 | ||
41c594ab | 64 | smtc_idle_loop_hook(); |
c68644d3 | 65 | #endif |
7a7ac952 WZ |
66 | |
67 | if (cpu_wait) { | |
68 | /* Don't trace irqs off for idle */ | |
69 | stop_critical_timings(); | |
1da177e4 | 70 | (*cpu_wait)(); |
7a7ac952 WZ |
71 | start_critical_timings(); |
72 | } | |
41c594ab | 73 | } |
1b2bc75c RB |
74 | #ifdef CONFIG_HOTPLUG_CPU |
75 | if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map) && | |
76 | (system_state == SYSTEM_RUNNING || | |
77 | system_state == SYSTEM_BOOTING)) | |
78 | play_dead(); | |
79 | #endif | |
1268fbc7 FW |
80 | rcu_idle_exit(); |
81 | tick_nohz_idle_exit(); | |
bd2f5536 | 82 | schedule_preempt_disabled(); |
1da177e4 LT |
83 | } |
84 | } | |
85 | ||
86 | asmlinkage void ret_from_fork(void); | |
8f54bcac | 87 | asmlinkage void ret_from_kernel_thread(void); |
1da177e4 LT |
88 | |
89 | void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) | |
90 | { | |
91 | unsigned long status; | |
92 | ||
93 | /* New thread loses kernel privileges. */ | |
bbaf238b | 94 | status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK); |
875d43e7 | 95 | #ifdef CONFIG_64BIT |
293c5bd1 | 96 | status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR; |
1da177e4 LT |
97 | #endif |
98 | status |= KU_USER; | |
99 | regs->cp0_status = status; | |
100 | clear_used_math(); | |
e04582b7 | 101 | clear_fpu_owner(); |
e50c0a8f RB |
102 | if (cpu_has_dsp) |
103 | __init_dsp(); | |
1da177e4 LT |
104 | regs->cp0_epc = pc; |
105 | regs->regs[29] = sp; | |
1da177e4 LT |
106 | } |
107 | ||
108 | void exit_thread(void) | |
109 | { | |
110 | } | |
111 | ||
112 | void flush_thread(void) | |
113 | { | |
114 | } | |
115 | ||
6f2c55b8 | 116 | int copy_thread(unsigned long clone_flags, unsigned long usp, |
8f54bcac | 117 | unsigned long arg, struct task_struct *p, struct pt_regs *regs) |
1da177e4 | 118 | { |
75bb07e7 | 119 | struct thread_info *ti = task_thread_info(p); |
1da177e4 | 120 | struct pt_regs *childregs; |
484889fc | 121 | unsigned long childksp; |
3c37026d | 122 | p->set_child_tid = p->clear_child_tid = NULL; |
1da177e4 | 123 | |
75bb07e7 | 124 | childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; |
1da177e4 LT |
125 | |
126 | preempt_disable(); | |
127 | ||
e50c0a8f | 128 | if (is_fpu_owner()) |
1da177e4 | 129 | save_fp(p); |
e50c0a8f RB |
130 | |
131 | if (cpu_has_dsp) | |
132 | save_dsp(p); | |
1da177e4 LT |
133 | |
134 | preempt_enable(); | |
135 | ||
136 | /* set up new TSS. */ | |
137 | childregs = (struct pt_regs *) childksp - 1; | |
484889fc DD |
138 | /* Put the stack after the struct pt_regs. */ |
139 | childksp = (unsigned long) childregs; | |
8f54bcac AV |
140 | p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); |
141 | if (unlikely(p->flags & PF_KTHREAD)) { | |
142 | unsigned long status = p->thread.cp0_status; | |
143 | memset(childregs, 0, sizeof(struct pt_regs)); | |
144 | ti->addr_limit = KERNEL_DS; | |
145 | p->thread.reg16 = usp; /* fn */ | |
146 | p->thread.reg17 = arg; | |
147 | p->thread.reg29 = childksp; | |
148 | p->thread.reg31 = (unsigned long) ret_from_kernel_thread; | |
149 | #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) | |
150 | status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | | |
151 | ((status & (ST0_KUC | ST0_IEC)) << 2); | |
152 | #else | |
153 | status |= ST0_EXL; | |
154 | #endif | |
155 | childregs->cp0_status = status; | |
156 | return 0; | |
157 | } | |
1da177e4 LT |
158 | *childregs = *regs; |
159 | childregs->regs[7] = 0; /* Clear error flag */ | |
1da177e4 | 160 | childregs->regs[2] = 0; /* Child gets zero as return value */ |
8f54bcac AV |
161 | childregs->regs[29] = usp; |
162 | ti->addr_limit = USER_DS; | |
1da177e4 | 163 | |
1da177e4 LT |
164 | p->thread.reg29 = (unsigned long) childregs; |
165 | p->thread.reg31 = (unsigned long) ret_from_fork; | |
166 | ||
167 | /* | |
168 | * New tasks lose permission to use the fpu. This accelerates context | |
169 | * switching for most programs since they don't use the fpu. | |
170 | */ | |
1da177e4 | 171 | childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); |
1da177e4 | 172 | |
9cc12363 | 173 | #ifdef CONFIG_MIPS_MT_SMTC |
f088fc84 | 174 | /* |
9cc12363 KK |
175 | * SMTC restores TCStatus after Status, and the CU bits |
176 | * are aliased there. | |
f088fc84 | 177 | */ |
9cc12363 KK |
178 | childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1); |
179 | #endif | |
1da177e4 LT |
180 | clear_tsk_thread_flag(p, TIF_USEDFPU); |
181 | ||
f088fc84 | 182 | #ifdef CONFIG_MIPS_MT_FPAFF |
6657fe0a | 183 | clear_tsk_thread_flag(p, TIF_FPUBOUND); |
f088fc84 RB |
184 | #endif /* CONFIG_MIPS_MT_FPAFF */ |
185 | ||
3c37026d RB |
186 | if (clone_flags & CLONE_SETTLS) |
187 | ti->tp_value = regs->regs[7]; | |
188 | ||
1da177e4 LT |
189 | return 0; |
190 | } | |
191 | ||
192 | /* Fill in the fpu structure for a core dump.. */ | |
193 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) | |
194 | { | |
195 | memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu)); | |
196 | ||
197 | return 1; | |
198 | } | |
199 | ||
d56efda4 | 200 | void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs) |
1da177e4 LT |
201 | { |
202 | int i; | |
203 | ||
204 | for (i = 0; i < EF_R0; i++) | |
205 | gp[i] = 0; | |
206 | gp[EF_R0] = 0; | |
207 | for (i = 1; i <= 31; i++) | |
208 | gp[EF_R0 + i] = regs->regs[i]; | |
209 | gp[EF_R26] = 0; | |
210 | gp[EF_R27] = 0; | |
211 | gp[EF_LO] = regs->lo; | |
212 | gp[EF_HI] = regs->hi; | |
213 | gp[EF_CP0_EPC] = regs->cp0_epc; | |
214 | gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; | |
215 | gp[EF_CP0_STATUS] = regs->cp0_status; | |
216 | gp[EF_CP0_CAUSE] = regs->cp0_cause; | |
217 | #ifdef EF_UNUSED0 | |
218 | gp[EF_UNUSED0] = 0; | |
219 | #endif | |
220 | } | |
221 | ||
49a89efb | 222 | int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) |
71e0e556 | 223 | { |
40bc9c67 | 224 | elf_dump_regs(*regs, task_pt_regs(tsk)); |
71e0e556 RB |
225 | return 1; |
226 | } | |
227 | ||
49a89efb | 228 | int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) |
1da177e4 LT |
229 | { |
230 | memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu)); | |
231 | ||
232 | return 1; | |
233 | } | |
234 | ||
b5943182 FBH |
235 | /* |
236 | * | |
237 | */ | |
238 | struct mips_frame_info { | |
239 | void *func; | |
240 | unsigned long func_size; | |
241 | int frame_size; | |
242 | int pc_offset; | |
243 | }; | |
dc953df1 | 244 | |
c0efbb6d FBH |
245 | static inline int is_ra_save_ins(union mips_instruction *ip) |
246 | { | |
247 | /* sw / sd $ra, offset($sp) */ | |
248 | return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && | |
249 | ip->i_format.rs == 29 && | |
250 | ip->i_format.rt == 31; | |
251 | } | |
252 | ||
253 | static inline int is_jal_jalr_jr_ins(union mips_instruction *ip) | |
254 | { | |
255 | if (ip->j_format.opcode == jal_op) | |
256 | return 1; | |
257 | if (ip->r_format.opcode != spec_op) | |
258 | return 0; | |
259 | return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; | |
260 | } | |
261 | ||
262 | static inline int is_sp_move_ins(union mips_instruction *ip) | |
263 | { | |
264 | /* addiu/daddiu sp,sp,-imm */ | |
265 | if (ip->i_format.rs != 29 || ip->i_format.rt != 29) | |
266 | return 0; | |
267 | if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) | |
268 | return 1; | |
269 | return 0; | |
270 | } | |
271 | ||
f66686f7 | 272 | static int get_frame_info(struct mips_frame_info *info) |
1da177e4 | 273 | { |
c0efbb6d | 274 | union mips_instruction *ip = info->func; |
29b376ff FBH |
275 | unsigned max_insns = info->func_size / sizeof(union mips_instruction); |
276 | unsigned i; | |
c0efbb6d | 277 | |
1da177e4 | 278 | info->pc_offset = -1; |
63077519 | 279 | info->frame_size = 0; |
1da177e4 | 280 | |
29b376ff FBH |
281 | if (!ip) |
282 | goto err; | |
283 | ||
284 | if (max_insns == 0) | |
285 | max_insns = 128U; /* unknown function size */ | |
286 | max_insns = min(128U, max_insns); | |
287 | ||
c0efbb6d FBH |
288 | for (i = 0; i < max_insns; i++, ip++) { |
289 | ||
290 | if (is_jal_jalr_jr_ins(ip)) | |
63077519 | 291 | break; |
0cceb4aa FBH |
292 | if (!info->frame_size) { |
293 | if (is_sp_move_ins(ip)) | |
294 | info->frame_size = - ip->i_format.simmediate; | |
295 | continue; | |
63077519 | 296 | } |
0cceb4aa | 297 | if (info->pc_offset == -1 && is_ra_save_ins(ip)) { |
63077519 AN |
298 | info->pc_offset = |
299 | ip->i_format.simmediate / sizeof(long); | |
0cceb4aa | 300 | break; |
1da177e4 LT |
301 | } |
302 | } | |
f66686f7 AN |
303 | if (info->frame_size && info->pc_offset >= 0) /* nested */ |
304 | return 0; | |
305 | if (info->pc_offset < 0) /* leaf */ | |
306 | return 1; | |
307 | /* prologue seems boggus... */ | |
29b376ff | 308 | err: |
f66686f7 | 309 | return -1; |
1da177e4 LT |
310 | } |
311 | ||
b5943182 FBH |
312 | static struct mips_frame_info schedule_mfi __read_mostly; |
313 | ||
1da177e4 LT |
314 | static int __init frame_info_init(void) |
315 | { | |
b5943182 | 316 | unsigned long size = 0; |
63077519 | 317 | #ifdef CONFIG_KALLSYMS |
b5943182 | 318 | unsigned long ofs; |
b5943182 | 319 | |
55b74283 | 320 | kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs); |
63077519 | 321 | #endif |
b5943182 FBH |
322 | schedule_mfi.func = schedule; |
323 | schedule_mfi.func_size = size; | |
324 | ||
325 | get_frame_info(&schedule_mfi); | |
6057a798 FBH |
326 | |
327 | /* | |
328 | * Without schedule() frame info, result given by | |
329 | * thread_saved_pc() and get_wchan() are not reliable. | |
330 | */ | |
b5943182 | 331 | if (schedule_mfi.pc_offset < 0) |
6057a798 | 332 | printk("Can't analyze schedule() prologue at %p\n", schedule); |
63077519 | 333 | |
1da177e4 LT |
334 | return 0; |
335 | } | |
336 | ||
337 | arch_initcall(frame_info_init); | |
338 | ||
339 | /* | |
340 | * Return saved PC of a blocked thread. | |
341 | */ | |
342 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
343 | { | |
344 | struct thread_struct *t = &tsk->thread; | |
345 | ||
346 | /* New born processes are a special case */ | |
347 | if (t->reg31 == (unsigned long) ret_from_fork) | |
348 | return t->reg31; | |
b5943182 | 349 | if (schedule_mfi.pc_offset < 0) |
1da177e4 | 350 | return 0; |
b5943182 | 351 | return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; |
1da177e4 LT |
352 | } |
353 | ||
1da177e4 | 354 | |
f66686f7 | 355 | #ifdef CONFIG_KALLSYMS |
94ea09c6 DK |
356 | /* generic stack unwinding function */ |
357 | unsigned long notrace unwind_stack_by_address(unsigned long stack_page, | |
358 | unsigned long *sp, | |
359 | unsigned long pc, | |
360 | unsigned long *ra) | |
f66686f7 | 361 | { |
f66686f7 | 362 | struct mips_frame_info info; |
f66686f7 | 363 | unsigned long size, ofs; |
4d157d5e | 364 | int leaf; |
1924600c AN |
365 | extern void ret_from_irq(void); |
366 | extern void ret_from_exception(void); | |
f66686f7 | 367 | |
f66686f7 AN |
368 | if (!stack_page) |
369 | return 0; | |
370 | ||
1924600c AN |
371 | /* |
372 | * If we reached the bottom of interrupt context, | |
373 | * return saved pc in pt_regs. | |
374 | */ | |
375 | if (pc == (unsigned long)ret_from_irq || | |
376 | pc == (unsigned long)ret_from_exception) { | |
377 | struct pt_regs *regs; | |
378 | if (*sp >= stack_page && | |
379 | *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) { | |
380 | regs = (struct pt_regs *)*sp; | |
381 | pc = regs->cp0_epc; | |
382 | if (__kernel_text_address(pc)) { | |
383 | *sp = regs->regs[29]; | |
384 | *ra = regs->regs[31]; | |
385 | return pc; | |
386 | } | |
387 | } | |
388 | return 0; | |
389 | } | |
55b74283 | 390 | if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) |
f66686f7 | 391 | return 0; |
1fd69098 | 392 | /* |
25985edc | 393 | * Return ra if an exception occurred at the first instruction |
1fd69098 | 394 | */ |
1924600c AN |
395 | if (unlikely(ofs == 0)) { |
396 | pc = *ra; | |
397 | *ra = 0; | |
398 | return pc; | |
399 | } | |
f66686f7 AN |
400 | |
401 | info.func = (void *)(pc - ofs); | |
402 | info.func_size = ofs; /* analyze from start to ofs */ | |
4d157d5e FBH |
403 | leaf = get_frame_info(&info); |
404 | if (leaf < 0) | |
f66686f7 | 405 | return 0; |
4d157d5e FBH |
406 | |
407 | if (*sp < stack_page || | |
408 | *sp + info.frame_size > stack_page + THREAD_SIZE - 32) | |
f66686f7 AN |
409 | return 0; |
410 | ||
4d157d5e FBH |
411 | if (leaf) |
412 | /* | |
413 | * For some extreme cases, get_frame_info() can | |
414 | * consider wrongly a nested function as a leaf | |
415 | * one. In that cases avoid to return always the | |
416 | * same value. | |
417 | */ | |
1924600c | 418 | pc = pc != *ra ? *ra : 0; |
4d157d5e FBH |
419 | else |
420 | pc = ((unsigned long *)(*sp))[info.pc_offset]; | |
421 | ||
422 | *sp += info.frame_size; | |
1924600c | 423 | *ra = 0; |
4d157d5e | 424 | return __kernel_text_address(pc) ? pc : 0; |
f66686f7 | 425 | } |
94ea09c6 DK |
426 | EXPORT_SYMBOL(unwind_stack_by_address); |
427 | ||
428 | /* used by show_backtrace() */ | |
429 | unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, | |
430 | unsigned long pc, unsigned long *ra) | |
431 | { | |
432 | unsigned long stack_page = (unsigned long)task_stack_page(task); | |
433 | return unwind_stack_by_address(stack_page, sp, pc, ra); | |
434 | } | |
f66686f7 | 435 | #endif |
b5943182 FBH |
436 | |
437 | /* | |
438 | * get_wchan - a maintenance nightmare^W^Wpain in the ass ... | |
439 | */ | |
440 | unsigned long get_wchan(struct task_struct *task) | |
441 | { | |
442 | unsigned long pc = 0; | |
443 | #ifdef CONFIG_KALLSYMS | |
444 | unsigned long sp; | |
1924600c | 445 | unsigned long ra = 0; |
b5943182 FBH |
446 | #endif |
447 | ||
448 | if (!task || task == current || task->state == TASK_RUNNING) | |
449 | goto out; | |
450 | if (!task_stack_page(task)) | |
451 | goto out; | |
452 | ||
453 | pc = thread_saved_pc(task); | |
454 | ||
455 | #ifdef CONFIG_KALLSYMS | |
456 | sp = task->thread.reg29 + schedule_mfi.frame_size; | |
457 | ||
458 | while (in_sched_functions(pc)) | |
1924600c | 459 | pc = unwind_stack(task, &sp, pc, &ra); |
b5943182 FBH |
460 | #endif |
461 | ||
462 | out: | |
463 | return pc; | |
464 | } | |
94109102 FBH |
465 | |
466 | /* | |
467 | * Don't forget that the stack pointer must be aligned on a 8 bytes | |
468 | * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. | |
469 | */ | |
470 | unsigned long arch_align_stack(unsigned long sp) | |
471 | { | |
472 | if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) | |
473 | sp -= get_random_int() & ~PAGE_MASK; | |
474 | ||
475 | return sp & ALMASK; | |
476 | } |