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 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 | 52 | { |
1b2bc75c RB |
53 | int cpu; |
54 | ||
55 | /* CPU is going idle. */ | |
56 | cpu = smp_processor_id(); | |
57 | ||
1da177e4 LT |
58 | /* endless idle loop with no priority at all */ |
59 | while (1) { | |
b8f8c3cf | 60 | tick_nohz_stop_sched_tick(1); |
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 |
1da177e4 LT |
67 | if (cpu_wait) |
68 | (*cpu_wait)(); | |
41c594ab | 69 | } |
1b2bc75c RB |
70 | #ifdef CONFIG_HOTPLUG_CPU |
71 | if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map) && | |
72 | (system_state == SYSTEM_RUNNING || | |
73 | system_state == SYSTEM_BOOTING)) | |
74 | play_dead(); | |
75 | #endif | |
7bcf7717 | 76 | tick_nohz_restart_sched_tick(); |
5bfb5d69 | 77 | preempt_enable_no_resched(); |
1da177e4 | 78 | schedule(); |
5bfb5d69 | 79 | preempt_disable(); |
1da177e4 LT |
80 | } |
81 | } | |
82 | ||
83 | asmlinkage void ret_from_fork(void); | |
84 | ||
85 | void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) | |
86 | { | |
87 | unsigned long status; | |
88 | ||
89 | /* New thread loses kernel privileges. */ | |
bbaf238b | 90 | status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK); |
875d43e7 | 91 | #ifdef CONFIG_64BIT |
293c5bd1 | 92 | status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR; |
1da177e4 LT |
93 | #endif |
94 | status |= KU_USER; | |
95 | regs->cp0_status = status; | |
96 | clear_used_math(); | |
e04582b7 | 97 | clear_fpu_owner(); |
e50c0a8f RB |
98 | if (cpu_has_dsp) |
99 | __init_dsp(); | |
1da177e4 LT |
100 | regs->cp0_epc = pc; |
101 | regs->regs[29] = sp; | |
102 | current_thread_info()->addr_limit = USER_DS; | |
103 | } | |
104 | ||
105 | void exit_thread(void) | |
106 | { | |
107 | } | |
108 | ||
109 | void flush_thread(void) | |
110 | { | |
111 | } | |
112 | ||
6f2c55b8 | 113 | int copy_thread(unsigned long clone_flags, unsigned long usp, |
1da177e4 LT |
114 | unsigned long unused, struct task_struct *p, struct pt_regs *regs) |
115 | { | |
75bb07e7 | 116 | struct thread_info *ti = task_thread_info(p); |
1da177e4 | 117 | struct pt_regs *childregs; |
484889fc | 118 | unsigned long childksp; |
3c37026d | 119 | p->set_child_tid = p->clear_child_tid = NULL; |
1da177e4 | 120 | |
75bb07e7 | 121 | childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; |
1da177e4 LT |
122 | |
123 | preempt_disable(); | |
124 | ||
e50c0a8f | 125 | if (is_fpu_owner()) |
1da177e4 | 126 | save_fp(p); |
e50c0a8f RB |
127 | |
128 | if (cpu_has_dsp) | |
129 | save_dsp(p); | |
1da177e4 LT |
130 | |
131 | preempt_enable(); | |
132 | ||
133 | /* set up new TSS. */ | |
134 | childregs = (struct pt_regs *) childksp - 1; | |
484889fc DD |
135 | /* Put the stack after the struct pt_regs. */ |
136 | childksp = (unsigned long) childregs; | |
1da177e4 LT |
137 | *childregs = *regs; |
138 | childregs->regs[7] = 0; /* Clear error flag */ | |
139 | ||
1da177e4 LT |
140 | childregs->regs[2] = 0; /* Child gets zero as return value */ |
141 | regs->regs[2] = p->pid; | |
142 | ||
143 | if (childregs->cp0_status & ST0_CU0) { | |
144 | childregs->regs[28] = (unsigned long) ti; | |
145 | childregs->regs[29] = childksp; | |
146 | ti->addr_limit = KERNEL_DS; | |
147 | } else { | |
148 | childregs->regs[29] = usp; | |
149 | ti->addr_limit = USER_DS; | |
150 | } | |
151 | p->thread.reg29 = (unsigned long) childregs; | |
152 | p->thread.reg31 = (unsigned long) ret_from_fork; | |
153 | ||
154 | /* | |
155 | * New tasks lose permission to use the fpu. This accelerates context | |
156 | * switching for most programs since they don't use the fpu. | |
157 | */ | |
158 | p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); | |
159 | childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); | |
1da177e4 | 160 | |
9cc12363 | 161 | #ifdef CONFIG_MIPS_MT_SMTC |
f088fc84 | 162 | /* |
9cc12363 KK |
163 | * SMTC restores TCStatus after Status, and the CU bits |
164 | * are aliased there. | |
f088fc84 | 165 | */ |
9cc12363 KK |
166 | childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1); |
167 | #endif | |
1da177e4 LT |
168 | clear_tsk_thread_flag(p, TIF_USEDFPU); |
169 | ||
f088fc84 | 170 | #ifdef CONFIG_MIPS_MT_FPAFF |
6657fe0a | 171 | clear_tsk_thread_flag(p, TIF_FPUBOUND); |
f088fc84 RB |
172 | #endif /* CONFIG_MIPS_MT_FPAFF */ |
173 | ||
3c37026d RB |
174 | if (clone_flags & CLONE_SETTLS) |
175 | ti->tp_value = regs->regs[7]; | |
176 | ||
1da177e4 LT |
177 | return 0; |
178 | } | |
179 | ||
180 | /* Fill in the fpu structure for a core dump.. */ | |
181 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) | |
182 | { | |
183 | memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu)); | |
184 | ||
185 | return 1; | |
186 | } | |
187 | ||
d56efda4 | 188 | void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs) |
1da177e4 LT |
189 | { |
190 | int i; | |
191 | ||
192 | for (i = 0; i < EF_R0; i++) | |
193 | gp[i] = 0; | |
194 | gp[EF_R0] = 0; | |
195 | for (i = 1; i <= 31; i++) | |
196 | gp[EF_R0 + i] = regs->regs[i]; | |
197 | gp[EF_R26] = 0; | |
198 | gp[EF_R27] = 0; | |
199 | gp[EF_LO] = regs->lo; | |
200 | gp[EF_HI] = regs->hi; | |
201 | gp[EF_CP0_EPC] = regs->cp0_epc; | |
202 | gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; | |
203 | gp[EF_CP0_STATUS] = regs->cp0_status; | |
204 | gp[EF_CP0_CAUSE] = regs->cp0_cause; | |
205 | #ifdef EF_UNUSED0 | |
206 | gp[EF_UNUSED0] = 0; | |
207 | #endif | |
208 | } | |
209 | ||
49a89efb | 210 | int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) |
71e0e556 | 211 | { |
40bc9c67 | 212 | elf_dump_regs(*regs, task_pt_regs(tsk)); |
71e0e556 RB |
213 | return 1; |
214 | } | |
215 | ||
49a89efb | 216 | int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) |
1da177e4 LT |
217 | { |
218 | memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu)); | |
219 | ||
220 | return 1; | |
221 | } | |
222 | ||
223 | /* | |
224 | * Create a kernel thread | |
225 | */ | |
b3f6df9f | 226 | static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *)) |
1da177e4 LT |
227 | { |
228 | do_exit(fn(arg)); | |
229 | } | |
230 | ||
231 | long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
232 | { | |
233 | struct pt_regs regs; | |
234 | ||
235 | memset(®s, 0, sizeof(regs)); | |
236 | ||
237 | regs.regs[4] = (unsigned long) arg; | |
238 | regs.regs[5] = (unsigned long) fn; | |
239 | regs.cp0_epc = (unsigned long) kernel_thread_helper; | |
240 | regs.cp0_status = read_c0_status(); | |
241 | #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) | |
e5d77754 MR |
242 | regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | |
243 | ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2); | |
1da177e4 LT |
244 | #else |
245 | regs.cp0_status |= ST0_EXL; | |
246 | #endif | |
247 | ||
248 | /* Ok, create the new process.. */ | |
249 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); | |
250 | } | |
251 | ||
b5943182 FBH |
252 | /* |
253 | * | |
254 | */ | |
255 | struct mips_frame_info { | |
256 | void *func; | |
257 | unsigned long func_size; | |
258 | int frame_size; | |
259 | int pc_offset; | |
260 | }; | |
dc953df1 | 261 | |
c0efbb6d FBH |
262 | static inline int is_ra_save_ins(union mips_instruction *ip) |
263 | { | |
264 | /* sw / sd $ra, offset($sp) */ | |
265 | return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && | |
266 | ip->i_format.rs == 29 && | |
267 | ip->i_format.rt == 31; | |
268 | } | |
269 | ||
270 | static inline int is_jal_jalr_jr_ins(union mips_instruction *ip) | |
271 | { | |
272 | if (ip->j_format.opcode == jal_op) | |
273 | return 1; | |
274 | if (ip->r_format.opcode != spec_op) | |
275 | return 0; | |
276 | return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; | |
277 | } | |
278 | ||
279 | static inline int is_sp_move_ins(union mips_instruction *ip) | |
280 | { | |
281 | /* addiu/daddiu sp,sp,-imm */ | |
282 | if (ip->i_format.rs != 29 || ip->i_format.rt != 29) | |
283 | return 0; | |
284 | if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) | |
285 | return 1; | |
286 | return 0; | |
287 | } | |
288 | ||
f66686f7 | 289 | static int get_frame_info(struct mips_frame_info *info) |
1da177e4 | 290 | { |
c0efbb6d | 291 | union mips_instruction *ip = info->func; |
29b376ff FBH |
292 | unsigned max_insns = info->func_size / sizeof(union mips_instruction); |
293 | unsigned i; | |
c0efbb6d | 294 | |
1da177e4 | 295 | info->pc_offset = -1; |
63077519 | 296 | info->frame_size = 0; |
1da177e4 | 297 | |
29b376ff FBH |
298 | if (!ip) |
299 | goto err; | |
300 | ||
301 | if (max_insns == 0) | |
302 | max_insns = 128U; /* unknown function size */ | |
303 | max_insns = min(128U, max_insns); | |
304 | ||
c0efbb6d FBH |
305 | for (i = 0; i < max_insns; i++, ip++) { |
306 | ||
307 | if (is_jal_jalr_jr_ins(ip)) | |
63077519 | 308 | break; |
0cceb4aa FBH |
309 | if (!info->frame_size) { |
310 | if (is_sp_move_ins(ip)) | |
311 | info->frame_size = - ip->i_format.simmediate; | |
312 | continue; | |
63077519 | 313 | } |
0cceb4aa | 314 | if (info->pc_offset == -1 && is_ra_save_ins(ip)) { |
63077519 AN |
315 | info->pc_offset = |
316 | ip->i_format.simmediate / sizeof(long); | |
0cceb4aa | 317 | break; |
1da177e4 LT |
318 | } |
319 | } | |
f66686f7 AN |
320 | if (info->frame_size && info->pc_offset >= 0) /* nested */ |
321 | return 0; | |
322 | if (info->pc_offset < 0) /* leaf */ | |
323 | return 1; | |
324 | /* prologue seems boggus... */ | |
29b376ff | 325 | err: |
f66686f7 | 326 | return -1; |
1da177e4 LT |
327 | } |
328 | ||
b5943182 FBH |
329 | static struct mips_frame_info schedule_mfi __read_mostly; |
330 | ||
1da177e4 LT |
331 | static int __init frame_info_init(void) |
332 | { | |
b5943182 | 333 | unsigned long size = 0; |
63077519 | 334 | #ifdef CONFIG_KALLSYMS |
b5943182 | 335 | unsigned long ofs; |
b5943182 | 336 | |
55b74283 | 337 | kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs); |
63077519 | 338 | #endif |
b5943182 FBH |
339 | schedule_mfi.func = schedule; |
340 | schedule_mfi.func_size = size; | |
341 | ||
342 | get_frame_info(&schedule_mfi); | |
6057a798 FBH |
343 | |
344 | /* | |
345 | * Without schedule() frame info, result given by | |
346 | * thread_saved_pc() and get_wchan() are not reliable. | |
347 | */ | |
b5943182 | 348 | if (schedule_mfi.pc_offset < 0) |
6057a798 | 349 | printk("Can't analyze schedule() prologue at %p\n", schedule); |
63077519 | 350 | |
1da177e4 LT |
351 | return 0; |
352 | } | |
353 | ||
354 | arch_initcall(frame_info_init); | |
355 | ||
356 | /* | |
357 | * Return saved PC of a blocked thread. | |
358 | */ | |
359 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
360 | { | |
361 | struct thread_struct *t = &tsk->thread; | |
362 | ||
363 | /* New born processes are a special case */ | |
364 | if (t->reg31 == (unsigned long) ret_from_fork) | |
365 | return t->reg31; | |
b5943182 | 366 | if (schedule_mfi.pc_offset < 0) |
1da177e4 | 367 | return 0; |
b5943182 | 368 | return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; |
1da177e4 LT |
369 | } |
370 | ||
1da177e4 | 371 | |
f66686f7 | 372 | #ifdef CONFIG_KALLSYMS |
4d157d5e FBH |
373 | /* used by show_backtrace() */ |
374 | unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, | |
1924600c | 375 | unsigned long pc, unsigned long *ra) |
f66686f7 AN |
376 | { |
377 | unsigned long stack_page; | |
378 | struct mips_frame_info info; | |
f66686f7 | 379 | unsigned long size, ofs; |
4d157d5e | 380 | int leaf; |
1924600c AN |
381 | extern void ret_from_irq(void); |
382 | extern void ret_from_exception(void); | |
f66686f7 AN |
383 | |
384 | stack_page = (unsigned long)task_stack_page(task); | |
385 | if (!stack_page) | |
386 | return 0; | |
387 | ||
1924600c AN |
388 | /* |
389 | * If we reached the bottom of interrupt context, | |
390 | * return saved pc in pt_regs. | |
391 | */ | |
392 | if (pc == (unsigned long)ret_from_irq || | |
393 | pc == (unsigned long)ret_from_exception) { | |
394 | struct pt_regs *regs; | |
395 | if (*sp >= stack_page && | |
396 | *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) { | |
397 | regs = (struct pt_regs *)*sp; | |
398 | pc = regs->cp0_epc; | |
399 | if (__kernel_text_address(pc)) { | |
400 | *sp = regs->regs[29]; | |
401 | *ra = regs->regs[31]; | |
402 | return pc; | |
403 | } | |
404 | } | |
405 | return 0; | |
406 | } | |
55b74283 | 407 | if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) |
f66686f7 | 408 | return 0; |
1fd69098 FBH |
409 | /* |
410 | * Return ra if an exception occured at the first instruction | |
411 | */ | |
1924600c AN |
412 | if (unlikely(ofs == 0)) { |
413 | pc = *ra; | |
414 | *ra = 0; | |
415 | return pc; | |
416 | } | |
f66686f7 AN |
417 | |
418 | info.func = (void *)(pc - ofs); | |
419 | info.func_size = ofs; /* analyze from start to ofs */ | |
4d157d5e FBH |
420 | leaf = get_frame_info(&info); |
421 | if (leaf < 0) | |
f66686f7 | 422 | return 0; |
4d157d5e FBH |
423 | |
424 | if (*sp < stack_page || | |
425 | *sp + info.frame_size > stack_page + THREAD_SIZE - 32) | |
f66686f7 AN |
426 | return 0; |
427 | ||
4d157d5e FBH |
428 | if (leaf) |
429 | /* | |
430 | * For some extreme cases, get_frame_info() can | |
431 | * consider wrongly a nested function as a leaf | |
432 | * one. In that cases avoid to return always the | |
433 | * same value. | |
434 | */ | |
1924600c | 435 | pc = pc != *ra ? *ra : 0; |
4d157d5e FBH |
436 | else |
437 | pc = ((unsigned long *)(*sp))[info.pc_offset]; | |
438 | ||
439 | *sp += info.frame_size; | |
1924600c | 440 | *ra = 0; |
4d157d5e | 441 | return __kernel_text_address(pc) ? pc : 0; |
f66686f7 AN |
442 | } |
443 | #endif | |
b5943182 FBH |
444 | |
445 | /* | |
446 | * get_wchan - a maintenance nightmare^W^Wpain in the ass ... | |
447 | */ | |
448 | unsigned long get_wchan(struct task_struct *task) | |
449 | { | |
450 | unsigned long pc = 0; | |
451 | #ifdef CONFIG_KALLSYMS | |
452 | unsigned long sp; | |
1924600c | 453 | unsigned long ra = 0; |
b5943182 FBH |
454 | #endif |
455 | ||
456 | if (!task || task == current || task->state == TASK_RUNNING) | |
457 | goto out; | |
458 | if (!task_stack_page(task)) | |
459 | goto out; | |
460 | ||
461 | pc = thread_saved_pc(task); | |
462 | ||
463 | #ifdef CONFIG_KALLSYMS | |
464 | sp = task->thread.reg29 + schedule_mfi.frame_size; | |
465 | ||
466 | while (in_sched_functions(pc)) | |
1924600c | 467 | pc = unwind_stack(task, &sp, pc, &ra); |
b5943182 FBH |
468 | #endif |
469 | ||
470 | out: | |
471 | return pc; | |
472 | } | |
94109102 FBH |
473 | |
474 | /* | |
475 | * Don't forget that the stack pointer must be aligned on a 8 bytes | |
476 | * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. | |
477 | */ | |
478 | unsigned long arch_align_stack(unsigned long sp) | |
479 | { | |
480 | if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) | |
481 | sp -= get_random_int() & ~PAGE_MASK; | |
482 | ||
483 | return sp & ALMASK; | |
484 | } |