Commit | Line | Data |
---|---|---|
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> | |
35 | #include <asm/system.h> | |
36 | #include <asm/mipsregs.h> | |
37 | #include <asm/processor.h> | |
38 | #include <asm/uaccess.h> | |
39 | #include <asm/io.h> | |
40 | #include <asm/elf.h> | |
41 | #include <asm/isadep.h> | |
42 | #include <asm/inst.h> | |
1df0f0ff | 43 | #include <asm/stacktrace.h> |
1da177e4 | 44 | |
1da177e4 LT |
45 | /* |
46 | * The idle thread. There's no useful work to be done, so just try to conserve | |
47 | * power and have a low exit latency (ie sit in a loop waiting for somebody to | |
48 | * say that they'd like to reschedule) | |
49 | */ | |
b3f6df9f | 50 | void __noreturn cpu_idle(void) |
1da177e4 | 51 | { |
1b2bc75c RB |
52 | int cpu; |
53 | ||
54 | /* CPU is going idle. */ | |
55 | cpu = smp_processor_id(); | |
56 | ||
1da177e4 LT |
57 | /* endless idle loop with no priority at all */ |
58 | while (1) { | |
1268fbc7 FW |
59 | tick_nohz_idle_enter(); |
60 | rcu_idle_enter(); | |
1b2bc75c | 61 | while (!need_resched() && cpu_online(cpu)) { |
9cc12363 | 62 | #ifdef CONFIG_MIPS_MT_SMTC |
447deafb RB |
63 | extern void smtc_idle_loop_hook(void); |
64 | ||
41c594ab | 65 | smtc_idle_loop_hook(); |
c68644d3 | 66 | #endif |
7a7ac952 WZ |
67 | |
68 | if (cpu_wait) { | |
69 | /* Don't trace irqs off for idle */ | |
70 | stop_critical_timings(); | |
1da177e4 | 71 | (*cpu_wait)(); |
7a7ac952 WZ |
72 | start_critical_timings(); |
73 | } | |
41c594ab | 74 | } |
1b2bc75c RB |
75 | #ifdef CONFIG_HOTPLUG_CPU |
76 | if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map) && | |
77 | (system_state == SYSTEM_RUNNING || | |
78 | system_state == SYSTEM_BOOTING)) | |
79 | play_dead(); | |
80 | #endif | |
1268fbc7 FW |
81 | rcu_idle_exit(); |
82 | tick_nohz_idle_exit(); | |
bd2f5536 | 83 | schedule_preempt_disabled(); |
1da177e4 LT |
84 | } |
85 | } | |
86 | ||
87 | asmlinkage void ret_from_fork(void); | |
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, |
1da177e4 LT |
117 | unsigned long unused, struct task_struct *p, struct pt_regs *regs) |
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; | |
1da177e4 LT |
140 | *childregs = *regs; |
141 | childregs->regs[7] = 0; /* Clear error flag */ | |
142 | ||
1da177e4 | 143 | childregs->regs[2] = 0; /* Child gets zero as return value */ |
1da177e4 LT |
144 | |
145 | if (childregs->cp0_status & ST0_CU0) { | |
146 | childregs->regs[28] = (unsigned long) ti; | |
147 | childregs->regs[29] = childksp; | |
148 | ti->addr_limit = KERNEL_DS; | |
149 | } else { | |
150 | childregs->regs[29] = usp; | |
151 | ti->addr_limit = USER_DS; | |
152 | } | |
153 | p->thread.reg29 = (unsigned long) childregs; | |
154 | p->thread.reg31 = (unsigned long) ret_from_fork; | |
155 | ||
156 | /* | |
157 | * New tasks lose permission to use the fpu. This accelerates context | |
158 | * switching for most programs since they don't use the fpu. | |
159 | */ | |
160 | p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); | |
161 | childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); | |
1da177e4 | 162 | |
9cc12363 | 163 | #ifdef CONFIG_MIPS_MT_SMTC |
f088fc84 | 164 | /* |
9cc12363 KK |
165 | * SMTC restores TCStatus after Status, and the CU bits |
166 | * are aliased there. | |
f088fc84 | 167 | */ |
9cc12363 KK |
168 | childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1); |
169 | #endif | |
1da177e4 LT |
170 | clear_tsk_thread_flag(p, TIF_USEDFPU); |
171 | ||
f088fc84 | 172 | #ifdef CONFIG_MIPS_MT_FPAFF |
6657fe0a | 173 | clear_tsk_thread_flag(p, TIF_FPUBOUND); |
f088fc84 RB |
174 | #endif /* CONFIG_MIPS_MT_FPAFF */ |
175 | ||
3c37026d RB |
176 | if (clone_flags & CLONE_SETTLS) |
177 | ti->tp_value = regs->regs[7]; | |
178 | ||
1da177e4 LT |
179 | return 0; |
180 | } | |
181 | ||
182 | /* Fill in the fpu structure for a core dump.. */ | |
183 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) | |
184 | { | |
185 | memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu)); | |
186 | ||
187 | return 1; | |
188 | } | |
189 | ||
d56efda4 | 190 | void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs) |
1da177e4 LT |
191 | { |
192 | int i; | |
193 | ||
194 | for (i = 0; i < EF_R0; i++) | |
195 | gp[i] = 0; | |
196 | gp[EF_R0] = 0; | |
197 | for (i = 1; i <= 31; i++) | |
198 | gp[EF_R0 + i] = regs->regs[i]; | |
199 | gp[EF_R26] = 0; | |
200 | gp[EF_R27] = 0; | |
201 | gp[EF_LO] = regs->lo; | |
202 | gp[EF_HI] = regs->hi; | |
203 | gp[EF_CP0_EPC] = regs->cp0_epc; | |
204 | gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; | |
205 | gp[EF_CP0_STATUS] = regs->cp0_status; | |
206 | gp[EF_CP0_CAUSE] = regs->cp0_cause; | |
207 | #ifdef EF_UNUSED0 | |
208 | gp[EF_UNUSED0] = 0; | |
209 | #endif | |
210 | } | |
211 | ||
49a89efb | 212 | int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) |
71e0e556 | 213 | { |
40bc9c67 | 214 | elf_dump_regs(*regs, task_pt_regs(tsk)); |
71e0e556 RB |
215 | return 1; |
216 | } | |
217 | ||
49a89efb | 218 | int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) |
1da177e4 LT |
219 | { |
220 | memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu)); | |
221 | ||
222 | return 1; | |
223 | } | |
224 | ||
225 | /* | |
226 | * Create a kernel thread | |
227 | */ | |
b3f6df9f | 228 | static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *)) |
1da177e4 LT |
229 | { |
230 | do_exit(fn(arg)); | |
231 | } | |
232 | ||
233 | long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
234 | { | |
235 | struct pt_regs regs; | |
236 | ||
237 | memset(®s, 0, sizeof(regs)); | |
238 | ||
239 | regs.regs[4] = (unsigned long) arg; | |
240 | regs.regs[5] = (unsigned long) fn; | |
241 | regs.cp0_epc = (unsigned long) kernel_thread_helper; | |
242 | regs.cp0_status = read_c0_status(); | |
243 | #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) | |
e5d77754 MR |
244 | regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | |
245 | ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2); | |
1da177e4 LT |
246 | #else |
247 | regs.cp0_status |= ST0_EXL; | |
248 | #endif | |
249 | ||
250 | /* Ok, create the new process.. */ | |
251 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); | |
252 | } | |
253 | ||
b5943182 FBH |
254 | /* |
255 | * | |
256 | */ | |
257 | struct mips_frame_info { | |
258 | void *func; | |
259 | unsigned long func_size; | |
260 | int frame_size; | |
261 | int pc_offset; | |
262 | }; | |
dc953df1 | 263 | |
c0efbb6d FBH |
264 | static inline int is_ra_save_ins(union mips_instruction *ip) |
265 | { | |
266 | /* sw / sd $ra, offset($sp) */ | |
267 | return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && | |
268 | ip->i_format.rs == 29 && | |
269 | ip->i_format.rt == 31; | |
270 | } | |
271 | ||
272 | static inline int is_jal_jalr_jr_ins(union mips_instruction *ip) | |
273 | { | |
274 | if (ip->j_format.opcode == jal_op) | |
275 | return 1; | |
276 | if (ip->r_format.opcode != spec_op) | |
277 | return 0; | |
278 | return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; | |
279 | } | |
280 | ||
281 | static inline int is_sp_move_ins(union mips_instruction *ip) | |
282 | { | |
283 | /* addiu/daddiu sp,sp,-imm */ | |
284 | if (ip->i_format.rs != 29 || ip->i_format.rt != 29) | |
285 | return 0; | |
286 | if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) | |
287 | return 1; | |
288 | return 0; | |
289 | } | |
290 | ||
f66686f7 | 291 | static int get_frame_info(struct mips_frame_info *info) |
1da177e4 | 292 | { |
c0efbb6d | 293 | union mips_instruction *ip = info->func; |
29b376ff FBH |
294 | unsigned max_insns = info->func_size / sizeof(union mips_instruction); |
295 | unsigned i; | |
c0efbb6d | 296 | |
1da177e4 | 297 | info->pc_offset = -1; |
63077519 | 298 | info->frame_size = 0; |
1da177e4 | 299 | |
29b376ff FBH |
300 | if (!ip) |
301 | goto err; | |
302 | ||
303 | if (max_insns == 0) | |
304 | max_insns = 128U; /* unknown function size */ | |
305 | max_insns = min(128U, max_insns); | |
306 | ||
c0efbb6d FBH |
307 | for (i = 0; i < max_insns; i++, ip++) { |
308 | ||
309 | if (is_jal_jalr_jr_ins(ip)) | |
63077519 | 310 | break; |
0cceb4aa FBH |
311 | if (!info->frame_size) { |
312 | if (is_sp_move_ins(ip)) | |
313 | info->frame_size = - ip->i_format.simmediate; | |
314 | continue; | |
63077519 | 315 | } |
0cceb4aa | 316 | if (info->pc_offset == -1 && is_ra_save_ins(ip)) { |
63077519 AN |
317 | info->pc_offset = |
318 | ip->i_format.simmediate / sizeof(long); | |
0cceb4aa | 319 | break; |
1da177e4 LT |
320 | } |
321 | } | |
f66686f7 AN |
322 | if (info->frame_size && info->pc_offset >= 0) /* nested */ |
323 | return 0; | |
324 | if (info->pc_offset < 0) /* leaf */ | |
325 | return 1; | |
326 | /* prologue seems boggus... */ | |
29b376ff | 327 | err: |
f66686f7 | 328 | return -1; |
1da177e4 LT |
329 | } |
330 | ||
b5943182 FBH |
331 | static struct mips_frame_info schedule_mfi __read_mostly; |
332 | ||
1da177e4 LT |
333 | static int __init frame_info_init(void) |
334 | { | |
b5943182 | 335 | unsigned long size = 0; |
63077519 | 336 | #ifdef CONFIG_KALLSYMS |
b5943182 | 337 | unsigned long ofs; |
b5943182 | 338 | |
55b74283 | 339 | kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs); |
63077519 | 340 | #endif |
b5943182 FBH |
341 | schedule_mfi.func = schedule; |
342 | schedule_mfi.func_size = size; | |
343 | ||
344 | get_frame_info(&schedule_mfi); | |
6057a798 FBH |
345 | |
346 | /* | |
347 | * Without schedule() frame info, result given by | |
348 | * thread_saved_pc() and get_wchan() are not reliable. | |
349 | */ | |
b5943182 | 350 | if (schedule_mfi.pc_offset < 0) |
6057a798 | 351 | printk("Can't analyze schedule() prologue at %p\n", schedule); |
63077519 | 352 | |
1da177e4 LT |
353 | return 0; |
354 | } | |
355 | ||
356 | arch_initcall(frame_info_init); | |
357 | ||
358 | /* | |
359 | * Return saved PC of a blocked thread. | |
360 | */ | |
361 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
362 | { | |
363 | struct thread_struct *t = &tsk->thread; | |
364 | ||
365 | /* New born processes are a special case */ | |
366 | if (t->reg31 == (unsigned long) ret_from_fork) | |
367 | return t->reg31; | |
b5943182 | 368 | if (schedule_mfi.pc_offset < 0) |
1da177e4 | 369 | return 0; |
b5943182 | 370 | return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; |
1da177e4 LT |
371 | } |
372 | ||
1da177e4 | 373 | |
f66686f7 | 374 | #ifdef CONFIG_KALLSYMS |
94ea09c6 DK |
375 | /* generic stack unwinding function */ |
376 | unsigned long notrace unwind_stack_by_address(unsigned long stack_page, | |
377 | unsigned long *sp, | |
378 | unsigned long pc, | |
379 | unsigned long *ra) | |
f66686f7 | 380 | { |
f66686f7 | 381 | struct mips_frame_info info; |
f66686f7 | 382 | unsigned long size, ofs; |
4d157d5e | 383 | int leaf; |
1924600c AN |
384 | extern void ret_from_irq(void); |
385 | extern void ret_from_exception(void); | |
f66686f7 | 386 | |
f66686f7 AN |
387 | if (!stack_page) |
388 | return 0; | |
389 | ||
1924600c AN |
390 | /* |
391 | * If we reached the bottom of interrupt context, | |
392 | * return saved pc in pt_regs. | |
393 | */ | |
394 | if (pc == (unsigned long)ret_from_irq || | |
395 | pc == (unsigned long)ret_from_exception) { | |
396 | struct pt_regs *regs; | |
397 | if (*sp >= stack_page && | |
398 | *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) { | |
399 | regs = (struct pt_regs *)*sp; | |
400 | pc = regs->cp0_epc; | |
401 | if (__kernel_text_address(pc)) { | |
402 | *sp = regs->regs[29]; | |
403 | *ra = regs->regs[31]; | |
404 | return pc; | |
405 | } | |
406 | } | |
407 | return 0; | |
408 | } | |
55b74283 | 409 | if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) |
f66686f7 | 410 | return 0; |
1fd69098 | 411 | /* |
25985edc | 412 | * Return ra if an exception occurred at the first instruction |
1fd69098 | 413 | */ |
1924600c AN |
414 | if (unlikely(ofs == 0)) { |
415 | pc = *ra; | |
416 | *ra = 0; | |
417 | return pc; | |
418 | } | |
f66686f7 AN |
419 | |
420 | info.func = (void *)(pc - ofs); | |
421 | info.func_size = ofs; /* analyze from start to ofs */ | |
4d157d5e FBH |
422 | leaf = get_frame_info(&info); |
423 | if (leaf < 0) | |
f66686f7 | 424 | return 0; |
4d157d5e FBH |
425 | |
426 | if (*sp < stack_page || | |
427 | *sp + info.frame_size > stack_page + THREAD_SIZE - 32) | |
f66686f7 AN |
428 | return 0; |
429 | ||
4d157d5e FBH |
430 | if (leaf) |
431 | /* | |
432 | * For some extreme cases, get_frame_info() can | |
433 | * consider wrongly a nested function as a leaf | |
434 | * one. In that cases avoid to return always the | |
435 | * same value. | |
436 | */ | |
1924600c | 437 | pc = pc != *ra ? *ra : 0; |
4d157d5e FBH |
438 | else |
439 | pc = ((unsigned long *)(*sp))[info.pc_offset]; | |
440 | ||
441 | *sp += info.frame_size; | |
1924600c | 442 | *ra = 0; |
4d157d5e | 443 | return __kernel_text_address(pc) ? pc : 0; |
f66686f7 | 444 | } |
94ea09c6 DK |
445 | EXPORT_SYMBOL(unwind_stack_by_address); |
446 | ||
447 | /* used by show_backtrace() */ | |
448 | unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, | |
449 | unsigned long pc, unsigned long *ra) | |
450 | { | |
451 | unsigned long stack_page = (unsigned long)task_stack_page(task); | |
452 | return unwind_stack_by_address(stack_page, sp, pc, ra); | |
453 | } | |
f66686f7 | 454 | #endif |
b5943182 FBH |
455 | |
456 | /* | |
457 | * get_wchan - a maintenance nightmare^W^Wpain in the ass ... | |
458 | */ | |
459 | unsigned long get_wchan(struct task_struct *task) | |
460 | { | |
461 | unsigned long pc = 0; | |
462 | #ifdef CONFIG_KALLSYMS | |
463 | unsigned long sp; | |
1924600c | 464 | unsigned long ra = 0; |
b5943182 FBH |
465 | #endif |
466 | ||
467 | if (!task || task == current || task->state == TASK_RUNNING) | |
468 | goto out; | |
469 | if (!task_stack_page(task)) | |
470 | goto out; | |
471 | ||
472 | pc = thread_saved_pc(task); | |
473 | ||
474 | #ifdef CONFIG_KALLSYMS | |
475 | sp = task->thread.reg29 + schedule_mfi.frame_size; | |
476 | ||
477 | while (in_sched_functions(pc)) | |
1924600c | 478 | pc = unwind_stack(task, &sp, pc, &ra); |
b5943182 FBH |
479 | #endif |
480 | ||
481 | out: | |
482 | return pc; | |
483 | } | |
94109102 FBH |
484 | |
485 | /* | |
486 | * Don't forget that the stack pointer must be aligned on a 8 bytes | |
487 | * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. | |
488 | */ | |
489 | unsigned long arch_align_stack(unsigned long sp) | |
490 | { | |
491 | if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) | |
492 | sp -= get_random_int() & ~PAGE_MASK; | |
493 | ||
494 | return sp & ALMASK; | |
495 | } |