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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/sched.h>
13#include <linux/tick.h>
14#include <linux/kernel.h>
15#include <linux/mm.h>
16#include <linux/stddef.h>
17#include <linux/unistd.h>
18#include <linux/export.h>
19#include <linux/ptrace.h>
20#include <linux/mman.h>
21#include <linux/personality.h>
22#include <linux/sys.h>
23#include <linux/user.h>
24#include <linux/init.h>
25#include <linux/completion.h>
26#include <linux/kallsyms.h>
27#include <linux/random.h>
28
29#include <asm/asm.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/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>
42#include <asm/stacktrace.h>
43
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 */
49void __noreturn cpu_idle(void)
50{
51 int cpu;
52
53 /* CPU is going idle. */
54 cpu = smp_processor_id();
55
56 /* endless idle loop with no priority at all */
57 while (1) {
58 tick_nohz_idle_enter();
59 rcu_idle_enter();
60 while (!need_resched() && cpu_online(cpu)) {
61#ifdef CONFIG_MIPS_MT_SMTC
62 extern void smtc_idle_loop_hook(void);
63
64 smtc_idle_loop_hook();
65#endif
66
67 if (cpu_wait) {
68 /* Don't trace irqs off for idle */
69 stop_critical_timings();
70 (*cpu_wait)();
71 start_critical_timings();
72 }
73 }
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
80 rcu_idle_exit();
81 tick_nohz_idle_exit();
82 schedule_preempt_disabled();
83 }
84}
85
86asmlinkage void ret_from_fork(void);
87
88void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
89{
90 unsigned long status;
91
92 /* New thread loses kernel privileges. */
93 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
94#ifdef CONFIG_64BIT
95 status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
96#endif
97 status |= KU_USER;
98 regs->cp0_status = status;
99 clear_used_math();
100 clear_fpu_owner();
101 if (cpu_has_dsp)
102 __init_dsp();
103 regs->cp0_epc = pc;
104 regs->regs[29] = sp;
105}
106
107void exit_thread(void)
108{
109}
110
111void flush_thread(void)
112{
113}
114
115int copy_thread(unsigned long clone_flags, unsigned long usp,
116 unsigned long unused, struct task_struct *p, struct pt_regs *regs)
117{
118 struct thread_info *ti = task_thread_info(p);
119 struct pt_regs *childregs;
120 unsigned long childksp;
121 p->set_child_tid = p->clear_child_tid = NULL;
122
123 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
124
125 preempt_disable();
126
127 if (is_fpu_owner())
128 save_fp(p);
129
130 if (cpu_has_dsp)
131 save_dsp(p);
132
133 preempt_enable();
134
135 /* set up new TSS. */
136 childregs = (struct pt_regs *) childksp - 1;
137 /* Put the stack after the struct pt_regs. */
138 childksp = (unsigned long) childregs;
139 *childregs = *regs;
140 childregs->regs[7] = 0; /* Clear error flag */
141
142 childregs->regs[2] = 0; /* Child gets zero as return value */
143
144 if (childregs->cp0_status & ST0_CU0) {
145 childregs->regs[28] = (unsigned long) ti;
146 childregs->regs[29] = childksp;
147 ti->addr_limit = KERNEL_DS;
148 } else {
149 childregs->regs[29] = usp;
150 ti->addr_limit = USER_DS;
151 }
152 p->thread.reg29 = (unsigned long) childregs;
153 p->thread.reg31 = (unsigned long) ret_from_fork;
154
155 /*
156 * New tasks lose permission to use the fpu. This accelerates context
157 * switching for most programs since they don't use the fpu.
158 */
159 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
160 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
161
162#ifdef CONFIG_MIPS_MT_SMTC
163 /*
164 * SMTC restores TCStatus after Status, and the CU bits
165 * are aliased there.
166 */
167 childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1);
168#endif
169 clear_tsk_thread_flag(p, TIF_USEDFPU);
170
171#ifdef CONFIG_MIPS_MT_FPAFF
172 clear_tsk_thread_flag(p, TIF_FPUBOUND);
173#endif /* CONFIG_MIPS_MT_FPAFF */
174
175 if (clone_flags & CLONE_SETTLS)
176 ti->tp_value = regs->regs[7];
177
178 return 0;
179}
180
181/* Fill in the fpu structure for a core dump.. */
182int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
183{
184 memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu));
185
186 return 1;
187}
188
189void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)
190{
191 int i;
192
193 for (i = 0; i < EF_R0; i++)
194 gp[i] = 0;
195 gp[EF_R0] = 0;
196 for (i = 1; i <= 31; i++)
197 gp[EF_R0 + i] = regs->regs[i];
198 gp[EF_R26] = 0;
199 gp[EF_R27] = 0;
200 gp[EF_LO] = regs->lo;
201 gp[EF_HI] = regs->hi;
202 gp[EF_CP0_EPC] = regs->cp0_epc;
203 gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
204 gp[EF_CP0_STATUS] = regs->cp0_status;
205 gp[EF_CP0_CAUSE] = regs->cp0_cause;
206#ifdef EF_UNUSED0
207 gp[EF_UNUSED0] = 0;
208#endif
209}
210
211int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
212{
213 elf_dump_regs(*regs, task_pt_regs(tsk));
214 return 1;
215}
216
217int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr)
218{
219 memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
220
221 return 1;
222}
223
224/*
225 * Create a kernel thread
226 */
227static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))
228{
229 do_exit(fn(arg));
230}
231
232long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
233{
234 struct pt_regs regs;
235
236 memset(®s, 0, sizeof(regs));
237
238 regs.regs[4] = (unsigned long) arg;
239 regs.regs[5] = (unsigned long) fn;
240 regs.cp0_epc = (unsigned long) kernel_thread_helper;
241 regs.cp0_status = read_c0_status();
242#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
243 regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
244 ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2);
245#else
246 regs.cp0_status |= ST0_EXL;
247#endif
248
249 /* Ok, create the new process.. */
250 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
251}
252
253/*
254 *
255 */
256struct mips_frame_info {
257 void *func;
258 unsigned long func_size;
259 int frame_size;
260 int pc_offset;
261};
262
263static inline int is_ra_save_ins(union mips_instruction *ip)
264{
265 /* sw / sd $ra, offset($sp) */
266 return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
267 ip->i_format.rs == 29 &&
268 ip->i_format.rt == 31;
269}
270
271static inline int is_jal_jalr_jr_ins(union mips_instruction *ip)
272{
273 if (ip->j_format.opcode == jal_op)
274 return 1;
275 if (ip->r_format.opcode != spec_op)
276 return 0;
277 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
278}
279
280static inline int is_sp_move_ins(union mips_instruction *ip)
281{
282 /* addiu/daddiu sp,sp,-imm */
283 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
284 return 0;
285 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
286 return 1;
287 return 0;
288}
289
290static int get_frame_info(struct mips_frame_info *info)
291{
292 union mips_instruction *ip = info->func;
293 unsigned max_insns = info->func_size / sizeof(union mips_instruction);
294 unsigned i;
295
296 info->pc_offset = -1;
297 info->frame_size = 0;
298
299 if (!ip)
300 goto err;
301
302 if (max_insns == 0)
303 max_insns = 128U; /* unknown function size */
304 max_insns = min(128U, max_insns);
305
306 for (i = 0; i < max_insns; i++, ip++) {
307
308 if (is_jal_jalr_jr_ins(ip))
309 break;
310 if (!info->frame_size) {
311 if (is_sp_move_ins(ip))
312 info->frame_size = - ip->i_format.simmediate;
313 continue;
314 }
315 if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
316 info->pc_offset =
317 ip->i_format.simmediate / sizeof(long);
318 break;
319 }
320 }
321 if (info->frame_size && info->pc_offset >= 0) /* nested */
322 return 0;
323 if (info->pc_offset < 0) /* leaf */
324 return 1;
325 /* prologue seems boggus... */
326err:
327 return -1;
328}
329
330static struct mips_frame_info schedule_mfi __read_mostly;
331
332static int __init frame_info_init(void)
333{
334 unsigned long size = 0;
335#ifdef CONFIG_KALLSYMS
336 unsigned long ofs;
337
338 kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);
339#endif
340 schedule_mfi.func = schedule;
341 schedule_mfi.func_size = size;
342
343 get_frame_info(&schedule_mfi);
344
345 /*
346 * Without schedule() frame info, result given by
347 * thread_saved_pc() and get_wchan() are not reliable.
348 */
349 if (schedule_mfi.pc_offset < 0)
350 printk("Can't analyze schedule() prologue at %p\n", schedule);
351
352 return 0;
353}
354
355arch_initcall(frame_info_init);
356
357/*
358 * Return saved PC of a blocked thread.
359 */
360unsigned long thread_saved_pc(struct task_struct *tsk)
361{
362 struct thread_struct *t = &tsk->thread;
363
364 /* New born processes are a special case */
365 if (t->reg31 == (unsigned long) ret_from_fork)
366 return t->reg31;
367 if (schedule_mfi.pc_offset < 0)
368 return 0;
369 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
370}
371
372
373#ifdef CONFIG_KALLSYMS
374/* generic stack unwinding function */
375unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
376 unsigned long *sp,
377 unsigned long pc,
378 unsigned long *ra)
379{
380 struct mips_frame_info info;
381 unsigned long size, ofs;
382 int leaf;
383 extern void ret_from_irq(void);
384 extern void ret_from_exception(void);
385
386 if (!stack_page)
387 return 0;
388
389 /*
390 * If we reached the bottom of interrupt context,
391 * return saved pc in pt_regs.
392 */
393 if (pc == (unsigned long)ret_from_irq ||
394 pc == (unsigned long)ret_from_exception) {
395 struct pt_regs *regs;
396 if (*sp >= stack_page &&
397 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
398 regs = (struct pt_regs *)*sp;
399 pc = regs->cp0_epc;
400 if (__kernel_text_address(pc)) {
401 *sp = regs->regs[29];
402 *ra = regs->regs[31];
403 return pc;
404 }
405 }
406 return 0;
407 }
408 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
409 return 0;
410 /*
411 * Return ra if an exception occurred at the first instruction
412 */
413 if (unlikely(ofs == 0)) {
414 pc = *ra;
415 *ra = 0;
416 return pc;
417 }
418
419 info.func = (void *)(pc - ofs);
420 info.func_size = ofs; /* analyze from start to ofs */
421 leaf = get_frame_info(&info);
422 if (leaf < 0)
423 return 0;
424
425 if (*sp < stack_page ||
426 *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
427 return 0;
428
429 if (leaf)
430 /*
431 * For some extreme cases, get_frame_info() can
432 * consider wrongly a nested function as a leaf
433 * one. In that cases avoid to return always the
434 * same value.
435 */
436 pc = pc != *ra ? *ra : 0;
437 else
438 pc = ((unsigned long *)(*sp))[info.pc_offset];
439
440 *sp += info.frame_size;
441 *ra = 0;
442 return __kernel_text_address(pc) ? pc : 0;
443}
444EXPORT_SYMBOL(unwind_stack_by_address);
445
446/* used by show_backtrace() */
447unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
448 unsigned long pc, unsigned long *ra)
449{
450 unsigned long stack_page = (unsigned long)task_stack_page(task);
451 return unwind_stack_by_address(stack_page, sp, pc, ra);
452}
453#endif
454
455/*
456 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
457 */
458unsigned long get_wchan(struct task_struct *task)
459{
460 unsigned long pc = 0;
461#ifdef CONFIG_KALLSYMS
462 unsigned long sp;
463 unsigned long ra = 0;
464#endif
465
466 if (!task || task == current || task->state == TASK_RUNNING)
467 goto out;
468 if (!task_stack_page(task))
469 goto out;
470
471 pc = thread_saved_pc(task);
472
473#ifdef CONFIG_KALLSYMS
474 sp = task->thread.reg29 + schedule_mfi.frame_size;
475
476 while (in_sched_functions(pc))
477 pc = unwind_stack(task, &sp, pc, &ra);
478#endif
479
480out:
481 return pc;
482}
483
484/*
485 * Don't forget that the stack pointer must be aligned on a 8 bytes
486 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
487 */
488unsigned long arch_align_stack(unsigned long sp)
489{
490 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
491 sp -= get_random_int() & ~PAGE_MASK;
492
493 return sp & ALMASK;
494}
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 * Copyright (C) 2013 Imagination Technologies Ltd.
11 */
12#include <linux/errno.h>
13#include <linux/sched.h>
14#include <linux/tick.h>
15#include <linux/kernel.h>
16#include <linux/mm.h>
17#include <linux/stddef.h>
18#include <linux/unistd.h>
19#include <linux/export.h>
20#include <linux/ptrace.h>
21#include <linux/mman.h>
22#include <linux/personality.h>
23#include <linux/sys.h>
24#include <linux/user.h>
25#include <linux/init.h>
26#include <linux/completion.h>
27#include <linux/kallsyms.h>
28#include <linux/random.h>
29
30#include <asm/asm.h>
31#include <asm/bootinfo.h>
32#include <asm/cpu.h>
33#include <asm/dsp.h>
34#include <asm/fpu.h>
35#include <asm/msa.h>
36#include <asm/pgtable.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>
44#include <asm/stacktrace.h>
45
46#ifdef CONFIG_HOTPLUG_CPU
47void arch_cpu_idle_dead(void)
48{
49 /* What the heck is this check doing ? */
50 if (!cpu_isset(smp_processor_id(), cpu_callin_map))
51 play_dead();
52}
53#endif
54
55asmlinkage void ret_from_fork(void);
56asmlinkage void ret_from_kernel_thread(void);
57
58void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
59{
60 unsigned long status;
61
62 /* New thread loses kernel privileges. */
63 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
64 status |= KU_USER;
65 regs->cp0_status = status;
66 clear_used_math();
67 clear_fpu_owner();
68 init_dsp();
69 clear_thread_flag(TIF_MSA_CTX_LIVE);
70 disable_msa();
71 regs->cp0_epc = pc;
72 regs->regs[29] = sp;
73}
74
75void exit_thread(void)
76{
77}
78
79void flush_thread(void)
80{
81}
82
83int copy_thread(unsigned long clone_flags, unsigned long usp,
84 unsigned long arg, struct task_struct *p)
85{
86 struct thread_info *ti = task_thread_info(p);
87 struct pt_regs *childregs, *regs = current_pt_regs();
88 unsigned long childksp;
89 p->set_child_tid = p->clear_child_tid = NULL;
90
91 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
92
93 preempt_disable();
94
95 if (is_msa_enabled())
96 save_msa(p);
97 else if (is_fpu_owner())
98 save_fp(p);
99
100 if (cpu_has_dsp)
101 save_dsp(p);
102
103 preempt_enable();
104
105 /* set up new TSS. */
106 childregs = (struct pt_regs *) childksp - 1;
107 /* Put the stack after the struct pt_regs. */
108 childksp = (unsigned long) childregs;
109 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
110 if (unlikely(p->flags & PF_KTHREAD)) {
111 unsigned long status = p->thread.cp0_status;
112 memset(childregs, 0, sizeof(struct pt_regs));
113 ti->addr_limit = KERNEL_DS;
114 p->thread.reg16 = usp; /* fn */
115 p->thread.reg17 = arg;
116 p->thread.reg29 = childksp;
117 p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
118#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
119 status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
120 ((status & (ST0_KUC | ST0_IEC)) << 2);
121#else
122 status |= ST0_EXL;
123#endif
124 childregs->cp0_status = status;
125 return 0;
126 }
127 *childregs = *regs;
128 childregs->regs[7] = 0; /* Clear error flag */
129 childregs->regs[2] = 0; /* Child gets zero as return value */
130 if (usp)
131 childregs->regs[29] = usp;
132 ti->addr_limit = USER_DS;
133
134 p->thread.reg29 = (unsigned long) childregs;
135 p->thread.reg31 = (unsigned long) ret_from_fork;
136
137 /*
138 * New tasks lose permission to use the fpu. This accelerates context
139 * switching for most programs since they don't use the fpu.
140 */
141 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
142
143#ifdef CONFIG_MIPS_MT_SMTC
144 /*
145 * SMTC restores TCStatus after Status, and the CU bits
146 * are aliased there.
147 */
148 childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1);
149#endif
150 clear_tsk_thread_flag(p, TIF_USEDFPU);
151
152#ifdef CONFIG_MIPS_MT_FPAFF
153 clear_tsk_thread_flag(p, TIF_FPUBOUND);
154#endif /* CONFIG_MIPS_MT_FPAFF */
155
156 if (clone_flags & CLONE_SETTLS)
157 ti->tp_value = regs->regs[7];
158
159 return 0;
160}
161
162/* Fill in the fpu structure for a core dump.. */
163int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
164{
165 int i;
166
167 for (i = 0; i < NUM_FPU_REGS; i++)
168 memcpy(&r[i], ¤t->thread.fpu.fpr[i], sizeof(*r));
169
170 memcpy(&r[NUM_FPU_REGS], ¤t->thread.fpu.fcr31,
171 sizeof(current->thread.fpu.fcr31));
172
173 return 1;
174}
175
176void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)
177{
178 int i;
179
180 for (i = 0; i < EF_R0; i++)
181 gp[i] = 0;
182 gp[EF_R0] = 0;
183 for (i = 1; i <= 31; i++)
184 gp[EF_R0 + i] = regs->regs[i];
185 gp[EF_R26] = 0;
186 gp[EF_R27] = 0;
187 gp[EF_LO] = regs->lo;
188 gp[EF_HI] = regs->hi;
189 gp[EF_CP0_EPC] = regs->cp0_epc;
190 gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
191 gp[EF_CP0_STATUS] = regs->cp0_status;
192 gp[EF_CP0_CAUSE] = regs->cp0_cause;
193#ifdef EF_UNUSED0
194 gp[EF_UNUSED0] = 0;
195#endif
196}
197
198int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
199{
200 elf_dump_regs(*regs, task_pt_regs(tsk));
201 return 1;
202}
203
204int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr)
205{
206 int i;
207
208 for (i = 0; i < NUM_FPU_REGS; i++)
209 memcpy(&fpr[i], &t->thread.fpu.fpr[i], sizeof(*fpr));
210
211 memcpy(&fpr[NUM_FPU_REGS], &t->thread.fpu.fcr31,
212 sizeof(t->thread.fpu.fcr31));
213
214 return 1;
215}
216
217#ifdef CONFIG_CC_STACKPROTECTOR
218#include <linux/stackprotector.h>
219unsigned long __stack_chk_guard __read_mostly;
220EXPORT_SYMBOL(__stack_chk_guard);
221#endif
222
223struct mips_frame_info {
224 void *func;
225 unsigned long func_size;
226 int frame_size;
227 int pc_offset;
228};
229
230#define J_TARGET(pc,target) \
231 (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
232
233static inline int is_ra_save_ins(union mips_instruction *ip)
234{
235#ifdef CONFIG_CPU_MICROMIPS
236 union mips_instruction mmi;
237
238 /*
239 * swsp ra,offset
240 * swm16 reglist,offset(sp)
241 * swm32 reglist,offset(sp)
242 * sw32 ra,offset(sp)
243 * jradiussp - NOT SUPPORTED
244 *
245 * microMIPS is way more fun...
246 */
247 if (mm_insn_16bit(ip->halfword[0])) {
248 mmi.word = (ip->halfword[0] << 16);
249 return ((mmi.mm16_r5_format.opcode == mm_swsp16_op &&
250 mmi.mm16_r5_format.rt == 31) ||
251 (mmi.mm16_m_format.opcode == mm_pool16c_op &&
252 mmi.mm16_m_format.func == mm_swm16_op));
253 }
254 else {
255 mmi.halfword[0] = ip->halfword[1];
256 mmi.halfword[1] = ip->halfword[0];
257 return ((mmi.mm_m_format.opcode == mm_pool32b_op &&
258 mmi.mm_m_format.rd > 9 &&
259 mmi.mm_m_format.base == 29 &&
260 mmi.mm_m_format.func == mm_swm32_func) ||
261 (mmi.i_format.opcode == mm_sw32_op &&
262 mmi.i_format.rs == 29 &&
263 mmi.i_format.rt == 31));
264 }
265#else
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#endif
271}
272
273static inline int is_jump_ins(union mips_instruction *ip)
274{
275#ifdef CONFIG_CPU_MICROMIPS
276 /*
277 * jr16,jrc,jalr16,jalr16
278 * jal
279 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
280 * jraddiusp - NOT SUPPORTED
281 *
282 * microMIPS is kind of more fun...
283 */
284 union mips_instruction mmi;
285
286 mmi.word = (ip->halfword[0] << 16);
287
288 if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
289 (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
290 ip->j_format.opcode == mm_jal32_op)
291 return 1;
292 if (ip->r_format.opcode != mm_pool32a_op ||
293 ip->r_format.func != mm_pool32axf_op)
294 return 0;
295 return (((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op);
296#else
297 if (ip->j_format.opcode == j_op)
298 return 1;
299 if (ip->j_format.opcode == jal_op)
300 return 1;
301 if (ip->r_format.opcode != spec_op)
302 return 0;
303 return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
304#endif
305}
306
307static inline int is_sp_move_ins(union mips_instruction *ip)
308{
309#ifdef CONFIG_CPU_MICROMIPS
310 /*
311 * addiusp -imm
312 * addius5 sp,-imm
313 * addiu32 sp,sp,-imm
314 * jradiussp - NOT SUPPORTED
315 *
316 * microMIPS is not more fun...
317 */
318 if (mm_insn_16bit(ip->halfword[0])) {
319 union mips_instruction mmi;
320
321 mmi.word = (ip->halfword[0] << 16);
322 return ((mmi.mm16_r3_format.opcode == mm_pool16d_op &&
323 mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
324 (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
325 mmi.mm16_r5_format.rt == 29));
326 }
327 return (ip->mm_i_format.opcode == mm_addiu32_op &&
328 ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29);
329#else
330 /* addiu/daddiu sp,sp,-imm */
331 if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
332 return 0;
333 if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
334 return 1;
335#endif
336 return 0;
337}
338
339static int get_frame_info(struct mips_frame_info *info)
340{
341#ifdef CONFIG_CPU_MICROMIPS
342 union mips_instruction *ip = (void *) (((char *) info->func) - 1);
343#else
344 union mips_instruction *ip = info->func;
345#endif
346 unsigned max_insns = info->func_size / sizeof(union mips_instruction);
347 unsigned i;
348
349 info->pc_offset = -1;
350 info->frame_size = 0;
351
352 if (!ip)
353 goto err;
354
355 if (max_insns == 0)
356 max_insns = 128U; /* unknown function size */
357 max_insns = min(128U, max_insns);
358
359 for (i = 0; i < max_insns; i++, ip++) {
360
361 if (is_jump_ins(ip))
362 break;
363 if (!info->frame_size) {
364 if (is_sp_move_ins(ip))
365 {
366#ifdef CONFIG_CPU_MICROMIPS
367 if (mm_insn_16bit(ip->halfword[0]))
368 {
369 unsigned short tmp;
370
371 if (ip->halfword[0] & mm_addiusp_func)
372 {
373 tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
374 info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
375 } else {
376 tmp = (ip->halfword[0] >> 1);
377 info->frame_size = -(signed short)(tmp & 0xf);
378 }
379 ip = (void *) &ip->halfword[1];
380 ip--;
381 } else
382#endif
383 info->frame_size = - ip->i_format.simmediate;
384 }
385 continue;
386 }
387 if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
388 info->pc_offset =
389 ip->i_format.simmediate / sizeof(long);
390 break;
391 }
392 }
393 if (info->frame_size && info->pc_offset >= 0) /* nested */
394 return 0;
395 if (info->pc_offset < 0) /* leaf */
396 return 1;
397 /* prologue seems boggus... */
398err:
399 return -1;
400}
401
402static struct mips_frame_info schedule_mfi __read_mostly;
403
404#ifdef CONFIG_KALLSYMS
405static unsigned long get___schedule_addr(void)
406{
407 return kallsyms_lookup_name("__schedule");
408}
409#else
410static unsigned long get___schedule_addr(void)
411{
412 union mips_instruction *ip = (void *)schedule;
413 int max_insns = 8;
414 int i;
415
416 for (i = 0; i < max_insns; i++, ip++) {
417 if (ip->j_format.opcode == j_op)
418 return J_TARGET(ip, ip->j_format.target);
419 }
420 return 0;
421}
422#endif
423
424static int __init frame_info_init(void)
425{
426 unsigned long size = 0;
427#ifdef CONFIG_KALLSYMS
428 unsigned long ofs;
429#endif
430 unsigned long addr;
431
432 addr = get___schedule_addr();
433 if (!addr)
434 addr = (unsigned long)schedule;
435
436#ifdef CONFIG_KALLSYMS
437 kallsyms_lookup_size_offset(addr, &size, &ofs);
438#endif
439 schedule_mfi.func = (void *)addr;
440 schedule_mfi.func_size = size;
441
442 get_frame_info(&schedule_mfi);
443
444 /*
445 * Without schedule() frame info, result given by
446 * thread_saved_pc() and get_wchan() are not reliable.
447 */
448 if (schedule_mfi.pc_offset < 0)
449 printk("Can't analyze schedule() prologue at %p\n", schedule);
450
451 return 0;
452}
453
454arch_initcall(frame_info_init);
455
456/*
457 * Return saved PC of a blocked thread.
458 */
459unsigned long thread_saved_pc(struct task_struct *tsk)
460{
461 struct thread_struct *t = &tsk->thread;
462
463 /* New born processes are a special case */
464 if (t->reg31 == (unsigned long) ret_from_fork)
465 return t->reg31;
466 if (schedule_mfi.pc_offset < 0)
467 return 0;
468 return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
469}
470
471
472#ifdef CONFIG_KALLSYMS
473/* generic stack unwinding function */
474unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
475 unsigned long *sp,
476 unsigned long pc,
477 unsigned long *ra)
478{
479 struct mips_frame_info info;
480 unsigned long size, ofs;
481 int leaf;
482 extern void ret_from_irq(void);
483 extern void ret_from_exception(void);
484
485 if (!stack_page)
486 return 0;
487
488 /*
489 * If we reached the bottom of interrupt context,
490 * return saved pc in pt_regs.
491 */
492 if (pc == (unsigned long)ret_from_irq ||
493 pc == (unsigned long)ret_from_exception) {
494 struct pt_regs *regs;
495 if (*sp >= stack_page &&
496 *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
497 regs = (struct pt_regs *)*sp;
498 pc = regs->cp0_epc;
499 if (__kernel_text_address(pc)) {
500 *sp = regs->regs[29];
501 *ra = regs->regs[31];
502 return pc;
503 }
504 }
505 return 0;
506 }
507 if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
508 return 0;
509 /*
510 * Return ra if an exception occurred at the first instruction
511 */
512 if (unlikely(ofs == 0)) {
513 pc = *ra;
514 *ra = 0;
515 return pc;
516 }
517
518 info.func = (void *)(pc - ofs);
519 info.func_size = ofs; /* analyze from start to ofs */
520 leaf = get_frame_info(&info);
521 if (leaf < 0)
522 return 0;
523
524 if (*sp < stack_page ||
525 *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
526 return 0;
527
528 if (leaf)
529 /*
530 * For some extreme cases, get_frame_info() can
531 * consider wrongly a nested function as a leaf
532 * one. In that cases avoid to return always the
533 * same value.
534 */
535 pc = pc != *ra ? *ra : 0;
536 else
537 pc = ((unsigned long *)(*sp))[info.pc_offset];
538
539 *sp += info.frame_size;
540 *ra = 0;
541 return __kernel_text_address(pc) ? pc : 0;
542}
543EXPORT_SYMBOL(unwind_stack_by_address);
544
545/* used by show_backtrace() */
546unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
547 unsigned long pc, unsigned long *ra)
548{
549 unsigned long stack_page = (unsigned long)task_stack_page(task);
550 return unwind_stack_by_address(stack_page, sp, pc, ra);
551}
552#endif
553
554/*
555 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
556 */
557unsigned long get_wchan(struct task_struct *task)
558{
559 unsigned long pc = 0;
560#ifdef CONFIG_KALLSYMS
561 unsigned long sp;
562 unsigned long ra = 0;
563#endif
564
565 if (!task || task == current || task->state == TASK_RUNNING)
566 goto out;
567 if (!task_stack_page(task))
568 goto out;
569
570 pc = thread_saved_pc(task);
571
572#ifdef CONFIG_KALLSYMS
573 sp = task->thread.reg29 + schedule_mfi.frame_size;
574
575 while (in_sched_functions(pc))
576 pc = unwind_stack(task, &sp, pc, &ra);
577#endif
578
579out:
580 return pc;
581}
582
583/*
584 * Don't forget that the stack pointer must be aligned on a 8 bytes
585 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
586 */
587unsigned long arch_align_stack(unsigned long sp)
588{
589 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
590 sp -= get_random_int() & ~PAGE_MASK;
591
592 return sp & ALMASK;
593}