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 | |
34c2f668 | 10 | * Copyright (C) 2013 Imagination Technologies Ltd. |
1da177e4 | 11 | */ |
1da177e4 | 12 | #include <linux/errno.h> |
1da177e4 | 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> | |
cae39d13 | 19 | #include <linux/export.h> |
1da177e4 | 20 | #include <linux/ptrace.h> |
1da177e4 LT |
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> | |
1da177e4 LT |
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 | |
cdbedc61 TG |
45 | #ifdef CONFIG_HOTPLUG_CPU |
46 | void arch_cpu_idle_dead(void) | |
1da177e4 | 47 | { |
cdbedc61 TG |
48 | /* What the heck is this check doing ? */ |
49 | if (!cpu_isset(smp_processor_id(), cpu_callin_map)) | |
50 | play_dead(); | |
51 | } | |
52 | #endif | |
1b2bc75c | 53 | |
1da177e4 | 54 | asmlinkage void ret_from_fork(void); |
8f54bcac | 55 | asmlinkage void ret_from_kernel_thread(void); |
1da177e4 LT |
56 | |
57 | void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) | |
58 | { | |
59 | unsigned long status; | |
60 | ||
61 | /* New thread loses kernel privileges. */ | |
bbaf238b | 62 | status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK); |
1da177e4 LT |
63 | status |= KU_USER; |
64 | regs->cp0_status = status; | |
65 | clear_used_math(); | |
e04582b7 | 66 | clear_fpu_owner(); |
a3056b1c | 67 | init_dsp(); |
1da177e4 LT |
68 | regs->cp0_epc = pc; |
69 | regs->regs[29] = sp; | |
1da177e4 LT |
70 | } |
71 | ||
72 | void exit_thread(void) | |
73 | { | |
74 | } | |
75 | ||
76 | void flush_thread(void) | |
77 | { | |
78 | } | |
79 | ||
6f2c55b8 | 80 | int copy_thread(unsigned long clone_flags, unsigned long usp, |
afa86fc4 | 81 | unsigned long arg, struct task_struct *p) |
1da177e4 | 82 | { |
75bb07e7 | 83 | struct thread_info *ti = task_thread_info(p); |
afa86fc4 | 84 | struct pt_regs *childregs, *regs = current_pt_regs(); |
484889fc | 85 | unsigned long childksp; |
3c37026d | 86 | p->set_child_tid = p->clear_child_tid = NULL; |
1da177e4 | 87 | |
75bb07e7 | 88 | childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; |
1da177e4 LT |
89 | |
90 | preempt_disable(); | |
91 | ||
e50c0a8f | 92 | if (is_fpu_owner()) |
1da177e4 | 93 | save_fp(p); |
e50c0a8f RB |
94 | |
95 | if (cpu_has_dsp) | |
96 | save_dsp(p); | |
1da177e4 LT |
97 | |
98 | preempt_enable(); | |
99 | ||
100 | /* set up new TSS. */ | |
101 | childregs = (struct pt_regs *) childksp - 1; | |
484889fc DD |
102 | /* Put the stack after the struct pt_regs. */ |
103 | childksp = (unsigned long) childregs; | |
8f54bcac AV |
104 | p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); |
105 | if (unlikely(p->flags & PF_KTHREAD)) { | |
106 | unsigned long status = p->thread.cp0_status; | |
107 | memset(childregs, 0, sizeof(struct pt_regs)); | |
108 | ti->addr_limit = KERNEL_DS; | |
109 | p->thread.reg16 = usp; /* fn */ | |
110 | p->thread.reg17 = arg; | |
111 | p->thread.reg29 = childksp; | |
112 | p->thread.reg31 = (unsigned long) ret_from_kernel_thread; | |
113 | #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) | |
114 | status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | | |
115 | ((status & (ST0_KUC | ST0_IEC)) << 2); | |
116 | #else | |
117 | status |= ST0_EXL; | |
118 | #endif | |
119 | childregs->cp0_status = status; | |
120 | return 0; | |
121 | } | |
1da177e4 | 122 | *childregs = *regs; |
70342287 RB |
123 | childregs->regs[7] = 0; /* Clear error flag */ |
124 | childregs->regs[2] = 0; /* Child gets zero as return value */ | |
64b3122d AV |
125 | if (usp) |
126 | childregs->regs[29] = usp; | |
8f54bcac | 127 | ti->addr_limit = USER_DS; |
1da177e4 | 128 | |
1da177e4 LT |
129 | p->thread.reg29 = (unsigned long) childregs; |
130 | p->thread.reg31 = (unsigned long) ret_from_fork; | |
131 | ||
132 | /* | |
133 | * New tasks lose permission to use the fpu. This accelerates context | |
134 | * switching for most programs since they don't use the fpu. | |
135 | */ | |
1da177e4 | 136 | childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); |
1da177e4 | 137 | |
9cc12363 | 138 | #ifdef CONFIG_MIPS_MT_SMTC |
f088fc84 | 139 | /* |
9cc12363 KK |
140 | * SMTC restores TCStatus after Status, and the CU bits |
141 | * are aliased there. | |
f088fc84 | 142 | */ |
9cc12363 KK |
143 | childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1); |
144 | #endif | |
1da177e4 LT |
145 | clear_tsk_thread_flag(p, TIF_USEDFPU); |
146 | ||
f088fc84 | 147 | #ifdef CONFIG_MIPS_MT_FPAFF |
6657fe0a | 148 | clear_tsk_thread_flag(p, TIF_FPUBOUND); |
f088fc84 RB |
149 | #endif /* CONFIG_MIPS_MT_FPAFF */ |
150 | ||
3c37026d RB |
151 | if (clone_flags & CLONE_SETTLS) |
152 | ti->tp_value = regs->regs[7]; | |
153 | ||
1da177e4 LT |
154 | return 0; |
155 | } | |
156 | ||
157 | /* Fill in the fpu structure for a core dump.. */ | |
158 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) | |
159 | { | |
6cec7c4a PB |
160 | int i; |
161 | ||
162 | for (i = 0; i < NUM_FPU_REGS; i++) | |
163 | memcpy(&r[i], ¤t->thread.fpu.fpr[i], sizeof(*r)); | |
164 | ||
165 | memcpy(&r[NUM_FPU_REGS], ¤t->thread.fpu.fcr31, | |
166 | sizeof(current->thread.fpu.fcr31)); | |
1da177e4 LT |
167 | |
168 | return 1; | |
169 | } | |
170 | ||
d56efda4 | 171 | void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs) |
1da177e4 LT |
172 | { |
173 | int i; | |
174 | ||
175 | for (i = 0; i < EF_R0; i++) | |
176 | gp[i] = 0; | |
177 | gp[EF_R0] = 0; | |
178 | for (i = 1; i <= 31; i++) | |
179 | gp[EF_R0 + i] = regs->regs[i]; | |
180 | gp[EF_R26] = 0; | |
181 | gp[EF_R27] = 0; | |
182 | gp[EF_LO] = regs->lo; | |
183 | gp[EF_HI] = regs->hi; | |
184 | gp[EF_CP0_EPC] = regs->cp0_epc; | |
185 | gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr; | |
186 | gp[EF_CP0_STATUS] = regs->cp0_status; | |
187 | gp[EF_CP0_CAUSE] = regs->cp0_cause; | |
188 | #ifdef EF_UNUSED0 | |
189 | gp[EF_UNUSED0] = 0; | |
190 | #endif | |
191 | } | |
192 | ||
49a89efb | 193 | int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) |
71e0e556 | 194 | { |
40bc9c67 | 195 | elf_dump_regs(*regs, task_pt_regs(tsk)); |
71e0e556 RB |
196 | return 1; |
197 | } | |
198 | ||
49a89efb | 199 | int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) |
1da177e4 | 200 | { |
6cec7c4a PB |
201 | int i; |
202 | ||
203 | for (i = 0; i < NUM_FPU_REGS; i++) | |
204 | memcpy(&fpr[i], &t->thread.fpu.fpr[i], sizeof(*fpr)); | |
205 | ||
206 | memcpy(&fpr[NUM_FPU_REGS], &t->thread.fpu.fcr31, | |
207 | sizeof(t->thread.fpu.fcr31)); | |
1da177e4 LT |
208 | |
209 | return 1; | |
210 | } | |
211 | ||
36ecafc5 GF |
212 | #ifdef CONFIG_CC_STACKPROTECTOR |
213 | #include <linux/stackprotector.h> | |
214 | unsigned long __stack_chk_guard __read_mostly; | |
215 | EXPORT_SYMBOL(__stack_chk_guard); | |
216 | #endif | |
217 | ||
b5943182 FBH |
218 | struct mips_frame_info { |
219 | void *func; | |
220 | unsigned long func_size; | |
221 | int frame_size; | |
222 | int pc_offset; | |
223 | }; | |
dc953df1 | 224 | |
5000653e TW |
225 | #define J_TARGET(pc,target) \ |
226 | (((unsigned long)(pc) & 0xf0000000) | ((target) << 2)) | |
227 | ||
c0efbb6d FBH |
228 | static inline int is_ra_save_ins(union mips_instruction *ip) |
229 | { | |
34c2f668 LY |
230 | #ifdef CONFIG_CPU_MICROMIPS |
231 | union mips_instruction mmi; | |
232 | ||
233 | /* | |
234 | * swsp ra,offset | |
235 | * swm16 reglist,offset(sp) | |
236 | * swm32 reglist,offset(sp) | |
237 | * sw32 ra,offset(sp) | |
238 | * jradiussp - NOT SUPPORTED | |
239 | * | |
240 | * microMIPS is way more fun... | |
241 | */ | |
242 | if (mm_insn_16bit(ip->halfword[0])) { | |
243 | mmi.word = (ip->halfword[0] << 16); | |
244 | return ((mmi.mm16_r5_format.opcode == mm_swsp16_op && | |
245 | mmi.mm16_r5_format.rt == 31) || | |
246 | (mmi.mm16_m_format.opcode == mm_pool16c_op && | |
247 | mmi.mm16_m_format.func == mm_swm16_op)); | |
248 | } | |
249 | else { | |
250 | mmi.halfword[0] = ip->halfword[1]; | |
251 | mmi.halfword[1] = ip->halfword[0]; | |
252 | return ((mmi.mm_m_format.opcode == mm_pool32b_op && | |
253 | mmi.mm_m_format.rd > 9 && | |
254 | mmi.mm_m_format.base == 29 && | |
255 | mmi.mm_m_format.func == mm_swm32_func) || | |
256 | (mmi.i_format.opcode == mm_sw32_op && | |
257 | mmi.i_format.rs == 29 && | |
258 | mmi.i_format.rt == 31)); | |
259 | } | |
260 | #else | |
c0efbb6d FBH |
261 | /* sw / sd $ra, offset($sp) */ |
262 | return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && | |
263 | ip->i_format.rs == 29 && | |
264 | ip->i_format.rt == 31; | |
34c2f668 | 265 | #endif |
c0efbb6d FBH |
266 | } |
267 | ||
e7438c4b | 268 | static inline int is_jump_ins(union mips_instruction *ip) |
c0efbb6d | 269 | { |
34c2f668 LY |
270 | #ifdef CONFIG_CPU_MICROMIPS |
271 | /* | |
272 | * jr16,jrc,jalr16,jalr16 | |
273 | * jal | |
274 | * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb | |
275 | * jraddiusp - NOT SUPPORTED | |
276 | * | |
277 | * microMIPS is kind of more fun... | |
278 | */ | |
279 | union mips_instruction mmi; | |
280 | ||
281 | mmi.word = (ip->halfword[0] << 16); | |
282 | ||
283 | if ((mmi.mm16_r5_format.opcode == mm_pool16c_op && | |
284 | (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) || | |
285 | ip->j_format.opcode == mm_jal32_op) | |
286 | return 1; | |
287 | if (ip->r_format.opcode != mm_pool32a_op || | |
288 | ip->r_format.func != mm_pool32axf_op) | |
289 | return 0; | |
290 | return (((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op); | |
291 | #else | |
e7438c4b TW |
292 | if (ip->j_format.opcode == j_op) |
293 | return 1; | |
c0efbb6d FBH |
294 | if (ip->j_format.opcode == jal_op) |
295 | return 1; | |
296 | if (ip->r_format.opcode != spec_op) | |
297 | return 0; | |
298 | return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; | |
34c2f668 | 299 | #endif |
c0efbb6d FBH |
300 | } |
301 | ||
302 | static inline int is_sp_move_ins(union mips_instruction *ip) | |
303 | { | |
34c2f668 LY |
304 | #ifdef CONFIG_CPU_MICROMIPS |
305 | /* | |
306 | * addiusp -imm | |
307 | * addius5 sp,-imm | |
308 | * addiu32 sp,sp,-imm | |
309 | * jradiussp - NOT SUPPORTED | |
310 | * | |
311 | * microMIPS is not more fun... | |
312 | */ | |
313 | if (mm_insn_16bit(ip->halfword[0])) { | |
314 | union mips_instruction mmi; | |
315 | ||
316 | mmi.word = (ip->halfword[0] << 16); | |
317 | return ((mmi.mm16_r3_format.opcode == mm_pool16d_op && | |
318 | mmi.mm16_r3_format.simmediate && mm_addiusp_func) || | |
319 | (mmi.mm16_r5_format.opcode == mm_pool16d_op && | |
320 | mmi.mm16_r5_format.rt == 29)); | |
321 | } | |
322 | return (ip->mm_i_format.opcode == mm_addiu32_op && | |
323 | ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29); | |
324 | #else | |
c0efbb6d FBH |
325 | /* addiu/daddiu sp,sp,-imm */ |
326 | if (ip->i_format.rs != 29 || ip->i_format.rt != 29) | |
327 | return 0; | |
328 | if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) | |
329 | return 1; | |
34c2f668 | 330 | #endif |
c0efbb6d FBH |
331 | return 0; |
332 | } | |
333 | ||
f66686f7 | 334 | static int get_frame_info(struct mips_frame_info *info) |
1da177e4 | 335 | { |
34c2f668 LY |
336 | #ifdef CONFIG_CPU_MICROMIPS |
337 | union mips_instruction *ip = (void *) (((char *) info->func) - 1); | |
338 | #else | |
c0efbb6d | 339 | union mips_instruction *ip = info->func; |
34c2f668 | 340 | #endif |
29b376ff FBH |
341 | unsigned max_insns = info->func_size / sizeof(union mips_instruction); |
342 | unsigned i; | |
c0efbb6d | 343 | |
1da177e4 | 344 | info->pc_offset = -1; |
63077519 | 345 | info->frame_size = 0; |
1da177e4 | 346 | |
29b376ff FBH |
347 | if (!ip) |
348 | goto err; | |
349 | ||
350 | if (max_insns == 0) | |
351 | max_insns = 128U; /* unknown function size */ | |
352 | max_insns = min(128U, max_insns); | |
353 | ||
c0efbb6d FBH |
354 | for (i = 0; i < max_insns; i++, ip++) { |
355 | ||
e7438c4b | 356 | if (is_jump_ins(ip)) |
63077519 | 357 | break; |
0cceb4aa FBH |
358 | if (!info->frame_size) { |
359 | if (is_sp_move_ins(ip)) | |
34c2f668 LY |
360 | { |
361 | #ifdef CONFIG_CPU_MICROMIPS | |
362 | if (mm_insn_16bit(ip->halfword[0])) | |
363 | { | |
364 | unsigned short tmp; | |
365 | ||
366 | if (ip->halfword[0] & mm_addiusp_func) | |
367 | { | |
368 | tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2); | |
369 | info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0)); | |
370 | } else { | |
371 | tmp = (ip->halfword[0] >> 1); | |
372 | info->frame_size = -(signed short)(tmp & 0xf); | |
373 | } | |
374 | ip = (void *) &ip->halfword[1]; | |
375 | ip--; | |
376 | } else | |
377 | #endif | |
0cceb4aa | 378 | info->frame_size = - ip->i_format.simmediate; |
34c2f668 | 379 | } |
0cceb4aa | 380 | continue; |
63077519 | 381 | } |
0cceb4aa | 382 | if (info->pc_offset == -1 && is_ra_save_ins(ip)) { |
63077519 AN |
383 | info->pc_offset = |
384 | ip->i_format.simmediate / sizeof(long); | |
0cceb4aa | 385 | break; |
1da177e4 LT |
386 | } |
387 | } | |
f66686f7 AN |
388 | if (info->frame_size && info->pc_offset >= 0) /* nested */ |
389 | return 0; | |
390 | if (info->pc_offset < 0) /* leaf */ | |
391 | return 1; | |
392 | /* prologue seems boggus... */ | |
29b376ff | 393 | err: |
f66686f7 | 394 | return -1; |
1da177e4 LT |
395 | } |
396 | ||
b5943182 FBH |
397 | static struct mips_frame_info schedule_mfi __read_mostly; |
398 | ||
5000653e TW |
399 | #ifdef CONFIG_KALLSYMS |
400 | static unsigned long get___schedule_addr(void) | |
401 | { | |
402 | return kallsyms_lookup_name("__schedule"); | |
403 | } | |
404 | #else | |
405 | static unsigned long get___schedule_addr(void) | |
406 | { | |
407 | union mips_instruction *ip = (void *)schedule; | |
408 | int max_insns = 8; | |
409 | int i; | |
410 | ||
411 | for (i = 0; i < max_insns; i++, ip++) { | |
412 | if (ip->j_format.opcode == j_op) | |
413 | return J_TARGET(ip, ip->j_format.target); | |
414 | } | |
415 | return 0; | |
416 | } | |
417 | #endif | |
418 | ||
1da177e4 LT |
419 | static int __init frame_info_init(void) |
420 | { | |
b5943182 | 421 | unsigned long size = 0; |
63077519 | 422 | #ifdef CONFIG_KALLSYMS |
b5943182 | 423 | unsigned long ofs; |
5000653e TW |
424 | #endif |
425 | unsigned long addr; | |
b5943182 | 426 | |
5000653e TW |
427 | addr = get___schedule_addr(); |
428 | if (!addr) | |
429 | addr = (unsigned long)schedule; | |
430 | ||
431 | #ifdef CONFIG_KALLSYMS | |
432 | kallsyms_lookup_size_offset(addr, &size, &ofs); | |
63077519 | 433 | #endif |
5000653e | 434 | schedule_mfi.func = (void *)addr; |
b5943182 FBH |
435 | schedule_mfi.func_size = size; |
436 | ||
437 | get_frame_info(&schedule_mfi); | |
6057a798 FBH |
438 | |
439 | /* | |
440 | * Without schedule() frame info, result given by | |
441 | * thread_saved_pc() and get_wchan() are not reliable. | |
442 | */ | |
b5943182 | 443 | if (schedule_mfi.pc_offset < 0) |
6057a798 | 444 | printk("Can't analyze schedule() prologue at %p\n", schedule); |
63077519 | 445 | |
1da177e4 LT |
446 | return 0; |
447 | } | |
448 | ||
449 | arch_initcall(frame_info_init); | |
450 | ||
451 | /* | |
452 | * Return saved PC of a blocked thread. | |
453 | */ | |
454 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
455 | { | |
456 | struct thread_struct *t = &tsk->thread; | |
457 | ||
458 | /* New born processes are a special case */ | |
459 | if (t->reg31 == (unsigned long) ret_from_fork) | |
460 | return t->reg31; | |
b5943182 | 461 | if (schedule_mfi.pc_offset < 0) |
1da177e4 | 462 | return 0; |
b5943182 | 463 | return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; |
1da177e4 LT |
464 | } |
465 | ||
1da177e4 | 466 | |
f66686f7 | 467 | #ifdef CONFIG_KALLSYMS |
94ea09c6 DK |
468 | /* generic stack unwinding function */ |
469 | unsigned long notrace unwind_stack_by_address(unsigned long stack_page, | |
470 | unsigned long *sp, | |
471 | unsigned long pc, | |
472 | unsigned long *ra) | |
f66686f7 | 473 | { |
f66686f7 | 474 | struct mips_frame_info info; |
f66686f7 | 475 | unsigned long size, ofs; |
4d157d5e | 476 | int leaf; |
1924600c AN |
477 | extern void ret_from_irq(void); |
478 | extern void ret_from_exception(void); | |
f66686f7 | 479 | |
f66686f7 AN |
480 | if (!stack_page) |
481 | return 0; | |
482 | ||
1924600c AN |
483 | /* |
484 | * If we reached the bottom of interrupt context, | |
485 | * return saved pc in pt_regs. | |
486 | */ | |
487 | if (pc == (unsigned long)ret_from_irq || | |
488 | pc == (unsigned long)ret_from_exception) { | |
489 | struct pt_regs *regs; | |
490 | if (*sp >= stack_page && | |
491 | *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) { | |
492 | regs = (struct pt_regs *)*sp; | |
493 | pc = regs->cp0_epc; | |
494 | if (__kernel_text_address(pc)) { | |
495 | *sp = regs->regs[29]; | |
496 | *ra = regs->regs[31]; | |
497 | return pc; | |
498 | } | |
499 | } | |
500 | return 0; | |
501 | } | |
55b74283 | 502 | if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) |
f66686f7 | 503 | return 0; |
1fd69098 | 504 | /* |
25985edc | 505 | * Return ra if an exception occurred at the first instruction |
1fd69098 | 506 | */ |
1924600c AN |
507 | if (unlikely(ofs == 0)) { |
508 | pc = *ra; | |
509 | *ra = 0; | |
510 | return pc; | |
511 | } | |
f66686f7 AN |
512 | |
513 | info.func = (void *)(pc - ofs); | |
514 | info.func_size = ofs; /* analyze from start to ofs */ | |
4d157d5e FBH |
515 | leaf = get_frame_info(&info); |
516 | if (leaf < 0) | |
f66686f7 | 517 | return 0; |
4d157d5e FBH |
518 | |
519 | if (*sp < stack_page || | |
520 | *sp + info.frame_size > stack_page + THREAD_SIZE - 32) | |
f66686f7 AN |
521 | return 0; |
522 | ||
4d157d5e FBH |
523 | if (leaf) |
524 | /* | |
525 | * For some extreme cases, get_frame_info() can | |
526 | * consider wrongly a nested function as a leaf | |
527 | * one. In that cases avoid to return always the | |
528 | * same value. | |
529 | */ | |
1924600c | 530 | pc = pc != *ra ? *ra : 0; |
4d157d5e FBH |
531 | else |
532 | pc = ((unsigned long *)(*sp))[info.pc_offset]; | |
533 | ||
534 | *sp += info.frame_size; | |
1924600c | 535 | *ra = 0; |
4d157d5e | 536 | return __kernel_text_address(pc) ? pc : 0; |
f66686f7 | 537 | } |
94ea09c6 DK |
538 | EXPORT_SYMBOL(unwind_stack_by_address); |
539 | ||
540 | /* used by show_backtrace() */ | |
541 | unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, | |
542 | unsigned long pc, unsigned long *ra) | |
543 | { | |
544 | unsigned long stack_page = (unsigned long)task_stack_page(task); | |
545 | return unwind_stack_by_address(stack_page, sp, pc, ra); | |
546 | } | |
f66686f7 | 547 | #endif |
b5943182 FBH |
548 | |
549 | /* | |
550 | * get_wchan - a maintenance nightmare^W^Wpain in the ass ... | |
551 | */ | |
552 | unsigned long get_wchan(struct task_struct *task) | |
553 | { | |
554 | unsigned long pc = 0; | |
555 | #ifdef CONFIG_KALLSYMS | |
556 | unsigned long sp; | |
1924600c | 557 | unsigned long ra = 0; |
b5943182 FBH |
558 | #endif |
559 | ||
560 | if (!task || task == current || task->state == TASK_RUNNING) | |
561 | goto out; | |
562 | if (!task_stack_page(task)) | |
563 | goto out; | |
564 | ||
565 | pc = thread_saved_pc(task); | |
566 | ||
567 | #ifdef CONFIG_KALLSYMS | |
568 | sp = task->thread.reg29 + schedule_mfi.frame_size; | |
569 | ||
570 | while (in_sched_functions(pc)) | |
1924600c | 571 | pc = unwind_stack(task, &sp, pc, &ra); |
b5943182 FBH |
572 | #endif |
573 | ||
574 | out: | |
575 | return pc; | |
576 | } | |
94109102 FBH |
577 | |
578 | /* | |
579 | * Don't forget that the stack pointer must be aligned on a 8 bytes | |
580 | * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. | |
581 | */ | |
582 | unsigned long arch_align_stack(unsigned long sp) | |
583 | { | |
584 | if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) | |
585 | sp -= get_random_int() & ~PAGE_MASK; | |
586 | ||
587 | return sp & ALMASK; | |
588 | } |