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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) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org) | |
8 | * Copyright (C) 1999, 2000 Silicon Graphics, Inc. | |
9 | * Copyright (C) 2004 Thiemo Seufer | |
10 | */ | |
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 | #include <linux/kallsyms.h> | |
28 | ||
29 | #include <asm/abi.h> | |
30 | #include <asm/bootinfo.h> | |
31 | #include <asm/cpu.h> | |
32 | #include <asm/dsp.h> | |
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> | |
43 | #include <asm/stacktrace.h> | |
44 | #ifdef CONFIG_MIPS_MT_SMTC | |
45 | #include <asm/mipsmtregs.h> | |
46 | extern void smtc_idle_loop_hook(void); | |
47 | #endif /* CONFIG_MIPS_MT_SMTC */ | |
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 | #ifdef CONFIG_MIPS_MT_SMTC | |
60 | smtc_idle_loop_hook(); | |
61 | #endif /* CONFIG_MIPS_MT_SMTC */ | |
62 | if (cpu_wait) | |
63 | (*cpu_wait)(); | |
64 | } | |
65 | preempt_enable_no_resched(); | |
66 | schedule(); | |
67 | preempt_disable(); | |
68 | } | |
69 | } | |
70 | ||
71 | /* | |
72 | * Native o32 and N64 ABI without DSP ASE | |
73 | */ | |
74 | struct mips_abi mips_abi = { | |
75 | .do_signal = do_signal, | |
76 | #ifdef CONFIG_TRAD_SIGNALS | |
77 | .setup_frame = setup_frame, | |
78 | #endif | |
79 | .setup_rt_frame = setup_rt_frame | |
80 | }; | |
81 | ||
82 | #ifdef CONFIG_MIPS32_O32 | |
83 | /* | |
84 | * o32 compatibility on 64-bit kernels, without DSP ASE | |
85 | */ | |
86 | struct mips_abi mips_abi_32 = { | |
87 | .do_signal = do_signal32, | |
88 | .setup_frame = setup_frame_32, | |
89 | .setup_rt_frame = setup_rt_frame_32 | |
90 | }; | |
91 | #endif /* CONFIG_MIPS32_O32 */ | |
92 | ||
93 | #ifdef CONFIG_MIPS32_N32 | |
94 | /* | |
95 | * N32 on 64-bit kernels, without DSP ASE | |
96 | */ | |
97 | struct mips_abi mips_abi_n32 = { | |
98 | .do_signal = do_signal, | |
99 | .setup_rt_frame = setup_rt_frame_n32 | |
100 | }; | |
101 | #endif /* CONFIG_MIPS32_N32 */ | |
102 | ||
103 | asmlinkage void ret_from_fork(void); | |
104 | ||
105 | void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) | |
106 | { | |
107 | unsigned long status; | |
108 | ||
109 | /* New thread loses kernel privileges. */ | |
110 | status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|KU_MASK); | |
111 | #ifdef CONFIG_64BIT | |
112 | status &= ~ST0_FR; | |
113 | status |= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR; | |
114 | #endif | |
115 | status |= KU_USER; | |
116 | regs->cp0_status = status; | |
117 | clear_used_math(); | |
118 | lose_fpu(); | |
119 | if (cpu_has_dsp) | |
120 | __init_dsp(); | |
121 | regs->cp0_epc = pc; | |
122 | regs->regs[29] = sp; | |
123 | current_thread_info()->addr_limit = USER_DS; | |
124 | } | |
125 | ||
126 | void exit_thread(void) | |
127 | { | |
128 | } | |
129 | ||
130 | void flush_thread(void) | |
131 | { | |
132 | } | |
133 | ||
134 | int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, | |
135 | unsigned long unused, struct task_struct *p, struct pt_regs *regs) | |
136 | { | |
137 | struct thread_info *ti = task_thread_info(p); | |
138 | struct pt_regs *childregs; | |
139 | long childksp; | |
140 | p->set_child_tid = p->clear_child_tid = NULL; | |
141 | ||
142 | childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; | |
143 | ||
144 | preempt_disable(); | |
145 | ||
146 | if (is_fpu_owner()) | |
147 | save_fp(p); | |
148 | ||
149 | if (cpu_has_dsp) | |
150 | save_dsp(p); | |
151 | ||
152 | preempt_enable(); | |
153 | ||
154 | /* set up new TSS. */ | |
155 | childregs = (struct pt_regs *) childksp - 1; | |
156 | *childregs = *regs; | |
157 | childregs->regs[7] = 0; /* Clear error flag */ | |
158 | ||
159 | #if defined(CONFIG_BINFMT_IRIX) | |
160 | if (current->personality != PER_LINUX) { | |
161 | /* Under IRIX things are a little different. */ | |
162 | childregs->regs[3] = 1; | |
163 | regs->regs[3] = 0; | |
164 | } | |
165 | #endif | |
166 | childregs->regs[2] = 0; /* Child gets zero as return value */ | |
167 | regs->regs[2] = p->pid; | |
168 | ||
169 | if (childregs->cp0_status & ST0_CU0) { | |
170 | childregs->regs[28] = (unsigned long) ti; | |
171 | childregs->regs[29] = childksp; | |
172 | ti->addr_limit = KERNEL_DS; | |
173 | } else { | |
174 | childregs->regs[29] = usp; | |
175 | ti->addr_limit = USER_DS; | |
176 | } | |
177 | p->thread.reg29 = (unsigned long) childregs; | |
178 | p->thread.reg31 = (unsigned long) ret_from_fork; | |
179 | ||
180 | /* | |
181 | * New tasks lose permission to use the fpu. This accelerates context | |
182 | * switching for most programs since they don't use the fpu. | |
183 | */ | |
184 | p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); | |
185 | childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); | |
186 | clear_tsk_thread_flag(p, TIF_USEDFPU); | |
187 | ||
188 | #ifdef CONFIG_MIPS_MT_FPAFF | |
189 | /* | |
190 | * FPU affinity support is cleaner if we track the | |
191 | * user-visible CPU affinity from the very beginning. | |
192 | * The generic cpus_allowed mask will already have | |
193 | * been copied from the parent before copy_thread | |
194 | * is invoked. | |
195 | */ | |
196 | p->thread.user_cpus_allowed = p->cpus_allowed; | |
197 | #endif /* CONFIG_MIPS_MT_FPAFF */ | |
198 | ||
199 | if (clone_flags & CLONE_SETTLS) | |
200 | ti->tp_value = regs->regs[7]; | |
201 | ||
202 | return 0; | |
203 | } | |
204 | ||
205 | /* Fill in the fpu structure for a core dump.. */ | |
206 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) | |
207 | { | |
208 | memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu)); | |
209 | ||
210 | return 1; | |
211 | } | |
212 | ||
213 | void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs) | |
214 | { | |
215 | int i; | |
216 | ||
217 | for (i = 0; i < EF_R0; i++) | |
218 | gp[i] = 0; | |
219 | gp[EF_R0] = 0; | |
220 | for (i = 1; i <= 31; i++) | |
221 | gp[EF_R0 + i] = regs->regs[i]; | |
222 | gp[EF_R26] = 0; | |
223 | gp[EF_R27] = 0; | |
224 | gp[EF_LO] = regs->lo; | |
225 | gp[EF_HI] = regs->hi; | |
226 | gp[EF_CP0_EPC] = regs->cp0_epc; | |
227 | gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; | |
228 | gp[EF_CP0_STATUS] = regs->cp0_status; | |
229 | gp[EF_CP0_CAUSE] = regs->cp0_cause; | |
230 | #ifdef EF_UNUSED0 | |
231 | gp[EF_UNUSED0] = 0; | |
232 | #endif | |
233 | } | |
234 | ||
235 | int dump_task_regs (struct task_struct *tsk, elf_gregset_t *regs) | |
236 | { | |
237 | elf_dump_regs(*regs, task_pt_regs(tsk)); | |
238 | return 1; | |
239 | } | |
240 | ||
241 | int dump_task_fpu (struct task_struct *t, elf_fpregset_t *fpr) | |
242 | { | |
243 | memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu)); | |
244 | ||
245 | return 1; | |
246 | } | |
247 | ||
248 | /* | |
249 | * Create a kernel thread | |
250 | */ | |
251 | ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *)) | |
252 | { | |
253 | do_exit(fn(arg)); | |
254 | } | |
255 | ||
256 | long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) | |
257 | { | |
258 | struct pt_regs regs; | |
259 | ||
260 | memset(®s, 0, sizeof(regs)); | |
261 | ||
262 | regs.regs[4] = (unsigned long) arg; | |
263 | regs.regs[5] = (unsigned long) fn; | |
264 | regs.cp0_epc = (unsigned long) kernel_thread_helper; | |
265 | regs.cp0_status = read_c0_status(); | |
266 | #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) | |
267 | regs.cp0_status &= ~(ST0_KUP | ST0_IEC); | |
268 | regs.cp0_status |= ST0_IEP; | |
269 | #else | |
270 | regs.cp0_status |= ST0_EXL; | |
271 | #endif | |
272 | ||
273 | /* Ok, create the new process.. */ | |
274 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); | |
275 | } | |
276 | ||
277 | /* | |
278 | * | |
279 | */ | |
280 | struct mips_frame_info { | |
281 | void *func; | |
282 | unsigned long func_size; | |
283 | int frame_size; | |
284 | int pc_offset; | |
285 | }; | |
286 | ||
287 | static inline int is_ra_save_ins(union mips_instruction *ip) | |
288 | { | |
289 | /* sw / sd $ra, offset($sp) */ | |
290 | return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && | |
291 | ip->i_format.rs == 29 && | |
292 | ip->i_format.rt == 31; | |
293 | } | |
294 | ||
295 | static inline int is_jal_jalr_jr_ins(union mips_instruction *ip) | |
296 | { | |
297 | if (ip->j_format.opcode == jal_op) | |
298 | return 1; | |
299 | if (ip->r_format.opcode != spec_op) | |
300 | return 0; | |
301 | return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; | |
302 | } | |
303 | ||
304 | static inline int is_sp_move_ins(union mips_instruction *ip) | |
305 | { | |
306 | /* addiu/daddiu sp,sp,-imm */ | |
307 | if (ip->i_format.rs != 29 || ip->i_format.rt != 29) | |
308 | return 0; | |
309 | if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) | |
310 | return 1; | |
311 | return 0; | |
312 | } | |
313 | ||
314 | static int get_frame_info(struct mips_frame_info *info) | |
315 | { | |
316 | union mips_instruction *ip = info->func; | |
317 | unsigned max_insns = info->func_size / sizeof(union mips_instruction); | |
318 | unsigned i; | |
319 | ||
320 | info->pc_offset = -1; | |
321 | info->frame_size = 0; | |
322 | ||
323 | if (!ip) | |
324 | goto err; | |
325 | ||
326 | if (max_insns == 0) | |
327 | max_insns = 128U; /* unknown function size */ | |
328 | max_insns = min(128U, max_insns); | |
329 | ||
330 | for (i = 0; i < max_insns; i++, ip++) { | |
331 | ||
332 | if (is_jal_jalr_jr_ins(ip)) | |
333 | break; | |
334 | if (!info->frame_size) { | |
335 | if (is_sp_move_ins(ip)) | |
336 | info->frame_size = - ip->i_format.simmediate; | |
337 | continue; | |
338 | } | |
339 | if (info->pc_offset == -1 && is_ra_save_ins(ip)) { | |
340 | info->pc_offset = | |
341 | ip->i_format.simmediate / sizeof(long); | |
342 | break; | |
343 | } | |
344 | } | |
345 | if (info->frame_size && info->pc_offset >= 0) /* nested */ | |
346 | return 0; | |
347 | if (info->pc_offset < 0) /* leaf */ | |
348 | return 1; | |
349 | /* prologue seems boggus... */ | |
350 | err: | |
351 | return -1; | |
352 | } | |
353 | ||
354 | static struct mips_frame_info schedule_mfi __read_mostly; | |
355 | ||
356 | static int __init frame_info_init(void) | |
357 | { | |
358 | unsigned long size = 0; | |
359 | #ifdef CONFIG_KALLSYMS | |
360 | unsigned long ofs; | |
361 | char *modname; | |
362 | char namebuf[KSYM_NAME_LEN + 1]; | |
363 | ||
364 | kallsyms_lookup((unsigned long)schedule, &size, &ofs, &modname, namebuf); | |
365 | #endif | |
366 | schedule_mfi.func = schedule; | |
367 | schedule_mfi.func_size = size; | |
368 | ||
369 | get_frame_info(&schedule_mfi); | |
370 | ||
371 | /* | |
372 | * Without schedule() frame info, result given by | |
373 | * thread_saved_pc() and get_wchan() are not reliable. | |
374 | */ | |
375 | if (schedule_mfi.pc_offset < 0) | |
376 | printk("Can't analyze schedule() prologue at %p\n", schedule); | |
377 | ||
378 | return 0; | |
379 | } | |
380 | ||
381 | arch_initcall(frame_info_init); | |
382 | ||
383 | /* | |
384 | * Return saved PC of a blocked thread. | |
385 | */ | |
386 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
387 | { | |
388 | struct thread_struct *t = &tsk->thread; | |
389 | ||
390 | /* New born processes are a special case */ | |
391 | if (t->reg31 == (unsigned long) ret_from_fork) | |
392 | return t->reg31; | |
393 | if (schedule_mfi.pc_offset < 0) | |
394 | return 0; | |
395 | return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; | |
396 | } | |
397 | ||
398 | ||
399 | #ifdef CONFIG_KALLSYMS | |
400 | /* used by show_backtrace() */ | |
401 | unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, | |
402 | unsigned long pc, unsigned long ra) | |
403 | { | |
404 | unsigned long stack_page; | |
405 | struct mips_frame_info info; | |
406 | char *modname; | |
407 | char namebuf[KSYM_NAME_LEN + 1]; | |
408 | unsigned long size, ofs; | |
409 | int leaf; | |
410 | ||
411 | stack_page = (unsigned long)task_stack_page(task); | |
412 | if (!stack_page) | |
413 | return 0; | |
414 | ||
415 | if (!kallsyms_lookup(pc, &size, &ofs, &modname, namebuf)) | |
416 | return 0; | |
417 | /* | |
418 | * Return ra if an exception occured at the first instruction | |
419 | */ | |
420 | if (unlikely(ofs == 0)) | |
421 | return ra; | |
422 | ||
423 | info.func = (void *)(pc - ofs); | |
424 | info.func_size = ofs; /* analyze from start to ofs */ | |
425 | leaf = get_frame_info(&info); | |
426 | if (leaf < 0) | |
427 | return 0; | |
428 | ||
429 | if (*sp < stack_page || | |
430 | *sp + info.frame_size > stack_page + THREAD_SIZE - 32) | |
431 | return 0; | |
432 | ||
433 | if (leaf) | |
434 | /* | |
435 | * For some extreme cases, get_frame_info() can | |
436 | * consider wrongly a nested function as a leaf | |
437 | * one. In that cases avoid to return always the | |
438 | * same value. | |
439 | */ | |
440 | pc = pc != ra ? ra : 0; | |
441 | else | |
442 | pc = ((unsigned long *)(*sp))[info.pc_offset]; | |
443 | ||
444 | *sp += info.frame_size; | |
445 | return __kernel_text_address(pc) ? pc : 0; | |
446 | } | |
447 | #endif | |
448 | ||
449 | /* | |
450 | * get_wchan - a maintenance nightmare^W^Wpain in the ass ... | |
451 | */ | |
452 | unsigned long get_wchan(struct task_struct *task) | |
453 | { | |
454 | unsigned long pc = 0; | |
455 | #ifdef CONFIG_KALLSYMS | |
456 | unsigned long sp; | |
457 | #endif | |
458 | ||
459 | if (!task || task == current || task->state == TASK_RUNNING) | |
460 | goto out; | |
461 | if (!task_stack_page(task)) | |
462 | goto out; | |
463 | ||
464 | pc = thread_saved_pc(task); | |
465 | ||
466 | #ifdef CONFIG_KALLSYMS | |
467 | sp = task->thread.reg29 + schedule_mfi.frame_size; | |
468 | ||
469 | while (in_sched_functions(pc)) | |
470 | pc = unwind_stack(task, &sp, pc, 0); | |
471 | #endif | |
472 | ||
473 | out: | |
474 | return pc; | |
475 | } |