Commit | Line | Data |
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bd353861 MF |
1 | /* |
2 | * Copyright (C) 2009 Matt Fleming <matt@console-pimps.org> | |
3 | * | |
4 | * This file is subject to the terms and conditions of the GNU General Public | |
5 | * License. See the file "COPYING" in the main directory of this archive | |
6 | * for more details. | |
7 | * | |
8 | * This is an implementation of a DWARF unwinder. Its main purpose is | |
9 | * for generating stacktrace information. Based on the DWARF 3 | |
10 | * specification from http://www.dwarfstd.org. | |
11 | * | |
12 | * TODO: | |
13 | * - DWARF64 doesn't work. | |
97efbbd5 | 14 | * - Registers with DWARF_VAL_OFFSET rules aren't handled properly. |
bd353861 MF |
15 | */ |
16 | ||
17 | /* #define DEBUG */ | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/io.h> | |
20 | #include <linux/list.h> | |
fb3f3e7f | 21 | #include <linux/mempool.h> |
bd353861 | 22 | #include <linux/mm.h> |
5a3abba7 | 23 | #include <linux/elf.h> |
60339fad | 24 | #include <linux/ftrace.h> |
1d5cc550 | 25 | #include <linux/module.h> |
5a0e3ad6 | 26 | #include <linux/slab.h> |
bd353861 MF |
27 | #include <asm/dwarf.h> |
28 | #include <asm/unwinder.h> | |
29 | #include <asm/sections.h> | |
3497447f | 30 | #include <asm/unaligned.h> |
bd353861 MF |
31 | #include <asm/stacktrace.h> |
32 | ||
fb3f3e7f MF |
33 | /* Reserve enough memory for two stack frames */ |
34 | #define DWARF_FRAME_MIN_REQ 2 | |
35 | /* ... with 4 registers per frame. */ | |
36 | #define DWARF_REG_MIN_REQ (DWARF_FRAME_MIN_REQ * 4) | |
37 | ||
38 | static struct kmem_cache *dwarf_frame_cachep; | |
39 | static mempool_t *dwarf_frame_pool; | |
40 | ||
41 | static struct kmem_cache *dwarf_reg_cachep; | |
42 | static mempool_t *dwarf_reg_pool; | |
43 | ||
858918b7 | 44 | static struct rb_root cie_root; |
97f361e2 | 45 | static DEFINE_SPINLOCK(dwarf_cie_lock); |
bd353861 | 46 | |
858918b7 | 47 | static struct rb_root fde_root; |
97f361e2 | 48 | static DEFINE_SPINLOCK(dwarf_fde_lock); |
bd353861 MF |
49 | |
50 | static struct dwarf_cie *cached_cie; | |
51 | ||
8a37f520 PM |
52 | static unsigned int dwarf_unwinder_ready; |
53 | ||
fb3f3e7f MF |
54 | /** |
55 | * dwarf_frame_alloc_reg - allocate memory for a DWARF register | |
56 | * @frame: the DWARF frame whose list of registers we insert on | |
57 | * @reg_num: the register number | |
58 | * | |
59 | * Allocate space for, and initialise, a dwarf reg from | |
60 | * dwarf_reg_pool and insert it onto the (unsorted) linked-list of | |
61 | * dwarf registers for @frame. | |
bd353861 | 62 | * |
fb3f3e7f | 63 | * Return the initialised DWARF reg. |
bd353861 | 64 | */ |
fb3f3e7f MF |
65 | static struct dwarf_reg *dwarf_frame_alloc_reg(struct dwarf_frame *frame, |
66 | unsigned int reg_num) | |
bd353861 | 67 | { |
fb3f3e7f | 68 | struct dwarf_reg *reg; |
bd353861 | 69 | |
fb3f3e7f MF |
70 | reg = mempool_alloc(dwarf_reg_pool, GFP_ATOMIC); |
71 | if (!reg) { | |
72 | printk(KERN_WARNING "Unable to allocate a DWARF register\n"); | |
bd353861 MF |
73 | /* |
74 | * Let's just bomb hard here, we have no way to | |
75 | * gracefully recover. | |
76 | */ | |
b344e24a | 77 | UNWINDER_BUG(); |
bd353861 MF |
78 | } |
79 | ||
fb3f3e7f MF |
80 | reg->number = reg_num; |
81 | reg->addr = 0; | |
82 | reg->flags = 0; | |
83 | ||
84 | list_add(®->link, &frame->reg_list); | |
85 | ||
86 | return reg; | |
87 | } | |
88 | ||
89 | static void dwarf_frame_free_regs(struct dwarf_frame *frame) | |
90 | { | |
91 | struct dwarf_reg *reg, *n; | |
92 | ||
93 | list_for_each_entry_safe(reg, n, &frame->reg_list, link) { | |
94 | list_del(®->link); | |
95 | mempool_free(reg, dwarf_reg_pool); | |
96 | } | |
97 | } | |
98 | ||
99 | /** | |
100 | * dwarf_frame_reg - return a DWARF register | |
101 | * @frame: the DWARF frame to search in for @reg_num | |
102 | * @reg_num: the register number to search for | |
103 | * | |
104 | * Lookup and return the dwarf reg @reg_num for this frame. Return | |
105 | * NULL if @reg_num is an register invalid number. | |
106 | */ | |
107 | static struct dwarf_reg *dwarf_frame_reg(struct dwarf_frame *frame, | |
108 | unsigned int reg_num) | |
109 | { | |
110 | struct dwarf_reg *reg; | |
111 | ||
112 | list_for_each_entry(reg, &frame->reg_list, link) { | |
113 | if (reg->number == reg_num) | |
114 | return reg; | |
bd353861 MF |
115 | } |
116 | ||
fb3f3e7f | 117 | return NULL; |
bd353861 MF |
118 | } |
119 | ||
120 | /** | |
121 | * dwarf_read_addr - read dwarf data | |
122 | * @src: source address of data | |
123 | * @dst: destination address to store the data to | |
124 | * | |
125 | * Read 'n' bytes from @src, where 'n' is the size of an address on | |
126 | * the native machine. We return the number of bytes read, which | |
127 | * should always be 'n'. We also have to be careful when reading | |
128 | * from @src and writing to @dst, because they can be arbitrarily | |
129 | * aligned. Return 'n' - the number of bytes read. | |
130 | */ | |
3497447f | 131 | static inline int dwarf_read_addr(unsigned long *src, unsigned long *dst) |
bd353861 | 132 | { |
bf43a160 PM |
133 | u32 val = get_unaligned(src); |
134 | put_unaligned(val, dst); | |
bd353861 MF |
135 | return sizeof(unsigned long *); |
136 | } | |
137 | ||
138 | /** | |
139 | * dwarf_read_uleb128 - read unsigned LEB128 data | |
140 | * @addr: the address where the ULEB128 data is stored | |
141 | * @ret: address to store the result | |
142 | * | |
143 | * Decode an unsigned LEB128 encoded datum. The algorithm is taken | |
144 | * from Appendix C of the DWARF 3 spec. For information on the | |
145 | * encodings refer to section "7.6 - Variable Length Data". Return | |
146 | * the number of bytes read. | |
147 | */ | |
148 | static inline unsigned long dwarf_read_uleb128(char *addr, unsigned int *ret) | |
149 | { | |
150 | unsigned int result; | |
151 | unsigned char byte; | |
152 | int shift, count; | |
153 | ||
154 | result = 0; | |
155 | shift = 0; | |
156 | count = 0; | |
157 | ||
158 | while (1) { | |
159 | byte = __raw_readb(addr); | |
160 | addr++; | |
161 | count++; | |
162 | ||
163 | result |= (byte & 0x7f) << shift; | |
164 | shift += 7; | |
165 | ||
166 | if (!(byte & 0x80)) | |
167 | break; | |
168 | } | |
169 | ||
170 | *ret = result; | |
171 | ||
172 | return count; | |
173 | } | |
174 | ||
175 | /** | |
176 | * dwarf_read_leb128 - read signed LEB128 data | |
177 | * @addr: the address of the LEB128 encoded data | |
178 | * @ret: address to store the result | |
179 | * | |
180 | * Decode signed LEB128 data. The algorithm is taken from Appendix | |
181 | * C of the DWARF 3 spec. Return the number of bytes read. | |
182 | */ | |
183 | static inline unsigned long dwarf_read_leb128(char *addr, int *ret) | |
184 | { | |
185 | unsigned char byte; | |
186 | int result, shift; | |
187 | int num_bits; | |
188 | int count; | |
189 | ||
190 | result = 0; | |
191 | shift = 0; | |
192 | count = 0; | |
193 | ||
194 | while (1) { | |
195 | byte = __raw_readb(addr); | |
196 | addr++; | |
197 | result |= (byte & 0x7f) << shift; | |
198 | shift += 7; | |
199 | count++; | |
200 | ||
201 | if (!(byte & 0x80)) | |
202 | break; | |
203 | } | |
204 | ||
205 | /* The number of bits in a signed integer. */ | |
206 | num_bits = 8 * sizeof(result); | |
207 | ||
208 | if ((shift < num_bits) && (byte & 0x40)) | |
209 | result |= (-1 << shift); | |
210 | ||
211 | *ret = result; | |
212 | ||
213 | return count; | |
214 | } | |
215 | ||
216 | /** | |
217 | * dwarf_read_encoded_value - return the decoded value at @addr | |
218 | * @addr: the address of the encoded value | |
219 | * @val: where to write the decoded value | |
220 | * @encoding: the encoding with which we can decode @addr | |
221 | * | |
222 | * GCC emits encoded address in the .eh_frame FDE entries. Decode | |
223 | * the value at @addr using @encoding. The decoded value is written | |
224 | * to @val and the number of bytes read is returned. | |
225 | */ | |
226 | static int dwarf_read_encoded_value(char *addr, unsigned long *val, | |
227 | char encoding) | |
228 | { | |
229 | unsigned long decoded_addr = 0; | |
230 | int count = 0; | |
231 | ||
232 | switch (encoding & 0x70) { | |
233 | case DW_EH_PE_absptr: | |
234 | break; | |
235 | case DW_EH_PE_pcrel: | |
236 | decoded_addr = (unsigned long)addr; | |
237 | break; | |
238 | default: | |
239 | pr_debug("encoding=0x%x\n", (encoding & 0x70)); | |
b344e24a | 240 | UNWINDER_BUG(); |
bd353861 MF |
241 | } |
242 | ||
243 | if ((encoding & 0x07) == 0x00) | |
244 | encoding |= DW_EH_PE_udata4; | |
245 | ||
246 | switch (encoding & 0x0f) { | |
247 | case DW_EH_PE_sdata4: | |
248 | case DW_EH_PE_udata4: | |
249 | count += 4; | |
3497447f | 250 | decoded_addr += get_unaligned((u32 *)addr); |
bd353861 MF |
251 | __raw_writel(decoded_addr, val); |
252 | break; | |
253 | default: | |
254 | pr_debug("encoding=0x%x\n", encoding); | |
b344e24a | 255 | UNWINDER_BUG(); |
bd353861 MF |
256 | } |
257 | ||
258 | return count; | |
259 | } | |
260 | ||
261 | /** | |
262 | * dwarf_entry_len - return the length of an FDE or CIE | |
263 | * @addr: the address of the entry | |
264 | * @len: the length of the entry | |
265 | * | |
266 | * Read the initial_length field of the entry and store the size of | |
267 | * the entry in @len. We return the number of bytes read. Return a | |
268 | * count of 0 on error. | |
269 | */ | |
270 | static inline int dwarf_entry_len(char *addr, unsigned long *len) | |
271 | { | |
272 | u32 initial_len; | |
273 | int count; | |
274 | ||
3497447f | 275 | initial_len = get_unaligned((u32 *)addr); |
bd353861 MF |
276 | count = 4; |
277 | ||
278 | /* | |
279 | * An initial length field value in the range DW_LEN_EXT_LO - | |
280 | * DW_LEN_EXT_HI indicates an extension, and should not be | |
281 | * interpreted as a length. The only extension that we currently | |
282 | * understand is the use of DWARF64 addresses. | |
283 | */ | |
284 | if (initial_len >= DW_EXT_LO && initial_len <= DW_EXT_HI) { | |
285 | /* | |
286 | * The 64-bit length field immediately follows the | |
287 | * compulsory 32-bit length field. | |
288 | */ | |
289 | if (initial_len == DW_EXT_DWARF64) { | |
3497447f | 290 | *len = get_unaligned((u64 *)addr + 4); |
bd353861 MF |
291 | count = 12; |
292 | } else { | |
293 | printk(KERN_WARNING "Unknown DWARF extension\n"); | |
294 | count = 0; | |
295 | } | |
296 | } else | |
297 | *len = initial_len; | |
298 | ||
299 | return count; | |
300 | } | |
301 | ||
302 | /** | |
303 | * dwarf_lookup_cie - locate the cie | |
304 | * @cie_ptr: pointer to help with lookup | |
305 | */ | |
306 | static struct dwarf_cie *dwarf_lookup_cie(unsigned long cie_ptr) | |
307 | { | |
858918b7 MF |
308 | struct rb_node **rb_node = &cie_root.rb_node; |
309 | struct dwarf_cie *cie = NULL; | |
bd353861 MF |
310 | unsigned long flags; |
311 | ||
312 | spin_lock_irqsave(&dwarf_cie_lock, flags); | |
313 | ||
314 | /* | |
315 | * We've cached the last CIE we looked up because chances are | |
316 | * that the FDE wants this CIE. | |
317 | */ | |
318 | if (cached_cie && cached_cie->cie_pointer == cie_ptr) { | |
319 | cie = cached_cie; | |
320 | goto out; | |
321 | } | |
322 | ||
858918b7 MF |
323 | while (*rb_node) { |
324 | struct dwarf_cie *cie_tmp; | |
325 | ||
326 | cie_tmp = rb_entry(*rb_node, struct dwarf_cie, node); | |
327 | BUG_ON(!cie_tmp); | |
328 | ||
329 | if (cie_ptr == cie_tmp->cie_pointer) { | |
330 | cie = cie_tmp; | |
331 | cached_cie = cie_tmp; | |
332 | goto out; | |
333 | } else { | |
334 | if (cie_ptr < cie_tmp->cie_pointer) | |
335 | rb_node = &(*rb_node)->rb_left; | |
336 | else | |
337 | rb_node = &(*rb_node)->rb_right; | |
bd353861 MF |
338 | } |
339 | } | |
340 | ||
bd353861 MF |
341 | out: |
342 | spin_unlock_irqrestore(&dwarf_cie_lock, flags); | |
343 | return cie; | |
344 | } | |
345 | ||
346 | /** | |
347 | * dwarf_lookup_fde - locate the FDE that covers pc | |
348 | * @pc: the program counter | |
349 | */ | |
350 | struct dwarf_fde *dwarf_lookup_fde(unsigned long pc) | |
351 | { | |
858918b7 MF |
352 | struct rb_node **rb_node = &fde_root.rb_node; |
353 | struct dwarf_fde *fde = NULL; | |
bd353861 | 354 | unsigned long flags; |
bd353861 MF |
355 | |
356 | spin_lock_irqsave(&dwarf_fde_lock, flags); | |
97f361e2 | 357 | |
858918b7 MF |
358 | while (*rb_node) { |
359 | struct dwarf_fde *fde_tmp; | |
360 | unsigned long tmp_start, tmp_end; | |
bd353861 | 361 | |
858918b7 MF |
362 | fde_tmp = rb_entry(*rb_node, struct dwarf_fde, node); |
363 | BUG_ON(!fde_tmp); | |
bd353861 | 364 | |
858918b7 MF |
365 | tmp_start = fde_tmp->initial_location; |
366 | tmp_end = fde_tmp->initial_location + fde_tmp->address_range; | |
bd353861 | 367 | |
858918b7 MF |
368 | if (pc < tmp_start) { |
369 | rb_node = &(*rb_node)->rb_left; | |
370 | } else { | |
371 | if (pc < tmp_end) { | |
372 | fde = fde_tmp; | |
373 | goto out; | |
374 | } else | |
375 | rb_node = &(*rb_node)->rb_right; | |
376 | } | |
377 | } | |
bd353861 | 378 | |
858918b7 | 379 | out: |
bd353861 MF |
380 | spin_unlock_irqrestore(&dwarf_fde_lock, flags); |
381 | ||
382 | return fde; | |
383 | } | |
384 | ||
385 | /** | |
386 | * dwarf_cfa_execute_insns - execute instructions to calculate a CFA | |
387 | * @insn_start: address of the first instruction | |
388 | * @insn_end: address of the last instruction | |
389 | * @cie: the CIE for this function | |
390 | * @fde: the FDE for this function | |
391 | * @frame: the instructions calculate the CFA for this frame | |
392 | * @pc: the program counter of the address we're interested in | |
393 | * | |
394 | * Execute the Call Frame instruction sequence starting at | |
395 | * @insn_start and ending at @insn_end. The instructions describe | |
396 | * how to calculate the Canonical Frame Address of a stackframe. | |
397 | * Store the results in @frame. | |
398 | */ | |
399 | static int dwarf_cfa_execute_insns(unsigned char *insn_start, | |
400 | unsigned char *insn_end, | |
401 | struct dwarf_cie *cie, | |
402 | struct dwarf_fde *fde, | |
403 | struct dwarf_frame *frame, | |
b955873b | 404 | unsigned long pc) |
bd353861 MF |
405 | { |
406 | unsigned char insn; | |
407 | unsigned char *current_insn; | |
408 | unsigned int count, delta, reg, expr_len, offset; | |
fb3f3e7f | 409 | struct dwarf_reg *regp; |
bd353861 MF |
410 | |
411 | current_insn = insn_start; | |
412 | ||
b955873b | 413 | while (current_insn < insn_end && frame->pc <= pc) { |
bd353861 MF |
414 | insn = __raw_readb(current_insn++); |
415 | ||
416 | /* | |
417 | * Firstly, handle the opcodes that embed their operands | |
418 | * in the instructions. | |
419 | */ | |
420 | switch (DW_CFA_opcode(insn)) { | |
421 | case DW_CFA_advance_loc: | |
422 | delta = DW_CFA_operand(insn); | |
423 | delta *= cie->code_alignment_factor; | |
424 | frame->pc += delta; | |
425 | continue; | |
426 | /* NOTREACHED */ | |
427 | case DW_CFA_offset: | |
428 | reg = DW_CFA_operand(insn); | |
429 | count = dwarf_read_uleb128(current_insn, &offset); | |
430 | current_insn += count; | |
431 | offset *= cie->data_alignment_factor; | |
fb3f3e7f MF |
432 | regp = dwarf_frame_alloc_reg(frame, reg); |
433 | regp->addr = offset; | |
434 | regp->flags |= DWARF_REG_OFFSET; | |
bd353861 MF |
435 | continue; |
436 | /* NOTREACHED */ | |
437 | case DW_CFA_restore: | |
438 | reg = DW_CFA_operand(insn); | |
439 | continue; | |
440 | /* NOTREACHED */ | |
441 | } | |
442 | ||
443 | /* | |
444 | * Secondly, handle the opcodes that don't embed their | |
445 | * operands in the instruction. | |
446 | */ | |
447 | switch (insn) { | |
448 | case DW_CFA_nop: | |
449 | continue; | |
450 | case DW_CFA_advance_loc1: | |
451 | delta = *current_insn++; | |
452 | frame->pc += delta * cie->code_alignment_factor; | |
453 | break; | |
454 | case DW_CFA_advance_loc2: | |
3497447f | 455 | delta = get_unaligned((u16 *)current_insn); |
bd353861 MF |
456 | current_insn += 2; |
457 | frame->pc += delta * cie->code_alignment_factor; | |
458 | break; | |
459 | case DW_CFA_advance_loc4: | |
3497447f | 460 | delta = get_unaligned((u32 *)current_insn); |
bd353861 MF |
461 | current_insn += 4; |
462 | frame->pc += delta * cie->code_alignment_factor; | |
463 | break; | |
464 | case DW_CFA_offset_extended: | |
465 | count = dwarf_read_uleb128(current_insn, ®); | |
466 | current_insn += count; | |
467 | count = dwarf_read_uleb128(current_insn, &offset); | |
468 | current_insn += count; | |
469 | offset *= cie->data_alignment_factor; | |
470 | break; | |
471 | case DW_CFA_restore_extended: | |
472 | count = dwarf_read_uleb128(current_insn, ®); | |
473 | current_insn += count; | |
474 | break; | |
475 | case DW_CFA_undefined: | |
476 | count = dwarf_read_uleb128(current_insn, ®); | |
477 | current_insn += count; | |
5580e904 MF |
478 | regp = dwarf_frame_alloc_reg(frame, reg); |
479 | regp->flags |= DWARF_UNDEFINED; | |
bd353861 MF |
480 | break; |
481 | case DW_CFA_def_cfa: | |
482 | count = dwarf_read_uleb128(current_insn, | |
483 | &frame->cfa_register); | |
484 | current_insn += count; | |
485 | count = dwarf_read_uleb128(current_insn, | |
486 | &frame->cfa_offset); | |
487 | current_insn += count; | |
488 | ||
489 | frame->flags |= DWARF_FRAME_CFA_REG_OFFSET; | |
490 | break; | |
491 | case DW_CFA_def_cfa_register: | |
492 | count = dwarf_read_uleb128(current_insn, | |
493 | &frame->cfa_register); | |
494 | current_insn += count; | |
495 | frame->flags |= DWARF_FRAME_CFA_REG_OFFSET; | |
496 | break; | |
497 | case DW_CFA_def_cfa_offset: | |
498 | count = dwarf_read_uleb128(current_insn, &offset); | |
499 | current_insn += count; | |
500 | frame->cfa_offset = offset; | |
501 | break; | |
502 | case DW_CFA_def_cfa_expression: | |
503 | count = dwarf_read_uleb128(current_insn, &expr_len); | |
504 | current_insn += count; | |
505 | ||
506 | frame->cfa_expr = current_insn; | |
507 | frame->cfa_expr_len = expr_len; | |
508 | current_insn += expr_len; | |
509 | ||
510 | frame->flags |= DWARF_FRAME_CFA_REG_EXP; | |
511 | break; | |
512 | case DW_CFA_offset_extended_sf: | |
513 | count = dwarf_read_uleb128(current_insn, ®); | |
514 | current_insn += count; | |
515 | count = dwarf_read_leb128(current_insn, &offset); | |
516 | current_insn += count; | |
517 | offset *= cie->data_alignment_factor; | |
fb3f3e7f MF |
518 | regp = dwarf_frame_alloc_reg(frame, reg); |
519 | regp->flags |= DWARF_REG_OFFSET; | |
520 | regp->addr = offset; | |
bd353861 MF |
521 | break; |
522 | case DW_CFA_val_offset: | |
523 | count = dwarf_read_uleb128(current_insn, ®); | |
524 | current_insn += count; | |
525 | count = dwarf_read_leb128(current_insn, &offset); | |
526 | offset *= cie->data_alignment_factor; | |
fb3f3e7f | 527 | regp = dwarf_frame_alloc_reg(frame, reg); |
97efbbd5 | 528 | regp->flags |= DWARF_VAL_OFFSET; |
fb3f3e7f | 529 | regp->addr = offset; |
bd353861 | 530 | break; |
cd7246f0 MF |
531 | case DW_CFA_GNU_args_size: |
532 | count = dwarf_read_uleb128(current_insn, &offset); | |
533 | current_insn += count; | |
534 | break; | |
535 | case DW_CFA_GNU_negative_offset_extended: | |
536 | count = dwarf_read_uleb128(current_insn, ®); | |
537 | current_insn += count; | |
538 | count = dwarf_read_uleb128(current_insn, &offset); | |
539 | offset *= cie->data_alignment_factor; | |
fb3f3e7f MF |
540 | |
541 | regp = dwarf_frame_alloc_reg(frame, reg); | |
542 | regp->flags |= DWARF_REG_OFFSET; | |
543 | regp->addr = -offset; | |
cd7246f0 | 544 | break; |
bd353861 MF |
545 | default: |
546 | pr_debug("unhandled DWARF instruction 0x%x\n", insn); | |
b344e24a | 547 | UNWINDER_BUG(); |
bd353861 MF |
548 | break; |
549 | } | |
550 | } | |
551 | ||
552 | return 0; | |
553 | } | |
554 | ||
555 | /** | |
ed4fe7f4 MF |
556 | * dwarf_free_frame - free the memory allocated for @frame |
557 | * @frame: the frame to free | |
558 | */ | |
559 | void dwarf_free_frame(struct dwarf_frame *frame) | |
560 | { | |
561 | dwarf_frame_free_regs(frame); | |
562 | mempool_free(frame, dwarf_frame_pool); | |
563 | } | |
564 | ||
944a3438 MF |
565 | extern void ret_from_irq(void); |
566 | ||
bd353861 | 567 | /** |
c2d474d6 MF |
568 | * dwarf_unwind_stack - unwind the stack |
569 | * | |
bd353861 MF |
570 | * @pc: address of the function to unwind |
571 | * @prev: struct dwarf_frame of the previous stackframe on the callstack | |
572 | * | |
573 | * Return a struct dwarf_frame representing the most recent frame | |
574 | * on the callstack. Each of the lower (older) stack frames are | |
575 | * linked via the "prev" member. | |
576 | */ | |
858918b7 MF |
577 | struct dwarf_frame *dwarf_unwind_stack(unsigned long pc, |
578 | struct dwarf_frame *prev) | |
bd353861 MF |
579 | { |
580 | struct dwarf_frame *frame; | |
581 | struct dwarf_cie *cie; | |
582 | struct dwarf_fde *fde; | |
fb3f3e7f | 583 | struct dwarf_reg *reg; |
bd353861 | 584 | unsigned long addr; |
bd353861 | 585 | |
8a37f520 PM |
586 | /* |
587 | * If we've been called in to before initialization has | |
588 | * completed, bail out immediately. | |
589 | */ | |
590 | if (!dwarf_unwinder_ready) | |
591 | return NULL; | |
592 | ||
bd353861 | 593 | /* |
c2d474d6 MF |
594 | * If we're starting at the top of the stack we need get the |
595 | * contents of a physical register to get the CFA in order to | |
596 | * begin the virtual unwinding of the stack. | |
bd353861 | 597 | * |
f8264667 MF |
598 | * NOTE: the return address is guaranteed to be setup by the |
599 | * time this function makes its first function call. | |
bd353861 | 600 | */ |
421b5411 | 601 | if (!pc || !prev) |
b955873b | 602 | pc = (unsigned long)current_text_addr(); |
bd353861 | 603 | |
60339fad MF |
604 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
605 | /* | |
606 | * If our stack has been patched by the function graph tracer | |
607 | * then we might see the address of return_to_handler() where we | |
608 | * expected to find the real return address. | |
609 | */ | |
610 | if (pc == (unsigned long)&return_to_handler) { | |
611 | int index = current->curr_ret_stack; | |
612 | ||
613 | /* | |
614 | * We currently have no way of tracking how many | |
615 | * return_to_handler()'s we've seen. If there is more | |
616 | * than one patched return address on our stack, | |
617 | * complain loudly. | |
618 | */ | |
619 | WARN_ON(index > 0); | |
620 | ||
621 | pc = current->ret_stack[index].ret; | |
622 | } | |
623 | #endif | |
624 | ||
fb3f3e7f MF |
625 | frame = mempool_alloc(dwarf_frame_pool, GFP_ATOMIC); |
626 | if (!frame) { | |
627 | printk(KERN_ERR "Unable to allocate a dwarf frame\n"); | |
b344e24a | 628 | UNWINDER_BUG(); |
fb3f3e7f | 629 | } |
bd353861 | 630 | |
fb3f3e7f MF |
631 | INIT_LIST_HEAD(&frame->reg_list); |
632 | frame->flags = 0; | |
bd353861 | 633 | frame->prev = prev; |
fb3f3e7f | 634 | frame->return_addr = 0; |
bd353861 MF |
635 | |
636 | fde = dwarf_lookup_fde(pc); | |
637 | if (!fde) { | |
638 | /* | |
c2d474d6 MF |
639 | * This is our normal exit path. There are two reasons |
640 | * why we might exit here, | |
bd353861 MF |
641 | * |
642 | * a) pc has no asscociated DWARF frame info and so | |
643 | * we don't know how to unwind this frame. This is | |
644 | * usually the case when we're trying to unwind a | |
645 | * frame that was called from some assembly code | |
646 | * that has no DWARF info, e.g. syscalls. | |
647 | * | |
648 | * b) the DEBUG info for pc is bogus. There's | |
649 | * really no way to distinguish this case from the | |
650 | * case above, which sucks because we could print a | |
651 | * warning here. | |
652 | */ | |
fb3f3e7f | 653 | goto bail; |
bd353861 MF |
654 | } |
655 | ||
656 | cie = dwarf_lookup_cie(fde->cie_pointer); | |
657 | ||
658 | frame->pc = fde->initial_location; | |
659 | ||
660 | /* CIE initial instructions */ | |
661 | dwarf_cfa_execute_insns(cie->initial_instructions, | |
f8264667 | 662 | cie->instructions_end, cie, fde, |
b955873b | 663 | frame, pc); |
bd353861 MF |
664 | |
665 | /* FDE instructions */ | |
666 | dwarf_cfa_execute_insns(fde->instructions, fde->end, cie, | |
b955873b | 667 | fde, frame, pc); |
bd353861 MF |
668 | |
669 | /* Calculate the CFA */ | |
670 | switch (frame->flags) { | |
671 | case DWARF_FRAME_CFA_REG_OFFSET: | |
672 | if (prev) { | |
fb3f3e7f | 673 | reg = dwarf_frame_reg(prev, frame->cfa_register); |
b344e24a MF |
674 | UNWINDER_BUG_ON(!reg); |
675 | UNWINDER_BUG_ON(reg->flags != DWARF_REG_OFFSET); | |
bd353861 | 676 | |
fb3f3e7f | 677 | addr = prev->cfa + reg->addr; |
bd353861 MF |
678 | frame->cfa = __raw_readl(addr); |
679 | ||
680 | } else { | |
681 | /* | |
c2d474d6 MF |
682 | * Again, we're starting from the top of the |
683 | * stack. We need to physically read | |
684 | * the contents of a register in order to get | |
685 | * the Canonical Frame Address for this | |
bd353861 MF |
686 | * function. |
687 | */ | |
688 | frame->cfa = dwarf_read_arch_reg(frame->cfa_register); | |
689 | } | |
690 | ||
691 | frame->cfa += frame->cfa_offset; | |
692 | break; | |
693 | default: | |
b344e24a | 694 | UNWINDER_BUG(); |
bd353861 MF |
695 | } |
696 | ||
fb3f3e7f | 697 | reg = dwarf_frame_reg(frame, DWARF_ARCH_RA_REG); |
5580e904 MF |
698 | |
699 | /* | |
700 | * If we haven't seen the return address register or the return | |
701 | * address column is undefined then we must assume that this is | |
702 | * the end of the callstack. | |
703 | */ | |
704 | if (!reg || reg->flags == DWARF_UNDEFINED) | |
705 | goto bail; | |
706 | ||
b344e24a | 707 | UNWINDER_BUG_ON(reg->flags != DWARF_REG_OFFSET); |
bd353861 | 708 | |
fb3f3e7f | 709 | addr = frame->cfa + reg->addr; |
bd353861 MF |
710 | frame->return_addr = __raw_readl(addr); |
711 | ||
944a3438 MF |
712 | /* |
713 | * Ah, the joys of unwinding through interrupts. | |
714 | * | |
715 | * Interrupts are tricky - the DWARF info needs to be _really_ | |
716 | * accurate and unfortunately I'm seeing a lot of bogus DWARF | |
717 | * info. For example, I've seen interrupts occur in epilogues | |
718 | * just after the frame pointer (r14) had been restored. The | |
719 | * problem was that the DWARF info claimed that the CFA could be | |
720 | * reached by using the value of the frame pointer before it was | |
721 | * restored. | |
722 | * | |
723 | * So until the compiler can be trusted to produce reliable | |
724 | * DWARF info when it really matters, let's stop unwinding once | |
725 | * we've calculated the function that was interrupted. | |
726 | */ | |
727 | if (prev && prev->pc == (unsigned long)ret_from_irq) | |
728 | frame->return_addr = 0; | |
729 | ||
bd353861 | 730 | return frame; |
fb3f3e7f MF |
731 | |
732 | bail: | |
ed4fe7f4 | 733 | dwarf_free_frame(frame); |
fb3f3e7f | 734 | return NULL; |
bd353861 MF |
735 | } |
736 | ||
737 | static int dwarf_parse_cie(void *entry, void *p, unsigned long len, | |
a6a2f2ad | 738 | unsigned char *end, struct module *mod) |
bd353861 | 739 | { |
858918b7 | 740 | struct rb_node **rb_node = &cie_root.rb_node; |
4e1a2594 | 741 | struct rb_node *parent = *rb_node; |
bd353861 MF |
742 | struct dwarf_cie *cie; |
743 | unsigned long flags; | |
744 | int count; | |
745 | ||
746 | cie = kzalloc(sizeof(*cie), GFP_KERNEL); | |
747 | if (!cie) | |
748 | return -ENOMEM; | |
749 | ||
750 | cie->length = len; | |
751 | ||
752 | /* | |
753 | * Record the offset into the .eh_frame section | |
754 | * for this CIE. It allows this CIE to be | |
755 | * quickly and easily looked up from the | |
756 | * corresponding FDE. | |
757 | */ | |
758 | cie->cie_pointer = (unsigned long)entry; | |
759 | ||
760 | cie->version = *(char *)p++; | |
b344e24a | 761 | UNWINDER_BUG_ON(cie->version != 1); |
bd353861 MF |
762 | |
763 | cie->augmentation = p; | |
764 | p += strlen(cie->augmentation) + 1; | |
765 | ||
766 | count = dwarf_read_uleb128(p, &cie->code_alignment_factor); | |
767 | p += count; | |
768 | ||
769 | count = dwarf_read_leb128(p, &cie->data_alignment_factor); | |
770 | p += count; | |
771 | ||
772 | /* | |
773 | * Which column in the rule table contains the | |
774 | * return address? | |
775 | */ | |
776 | if (cie->version == 1) { | |
777 | cie->return_address_reg = __raw_readb(p); | |
778 | p++; | |
779 | } else { | |
780 | count = dwarf_read_uleb128(p, &cie->return_address_reg); | |
781 | p += count; | |
782 | } | |
783 | ||
784 | if (cie->augmentation[0] == 'z') { | |
785 | unsigned int length, count; | |
786 | cie->flags |= DWARF_CIE_Z_AUGMENTATION; | |
787 | ||
788 | count = dwarf_read_uleb128(p, &length); | |
789 | p += count; | |
790 | ||
b344e24a | 791 | UNWINDER_BUG_ON((unsigned char *)p > end); |
bd353861 MF |
792 | |
793 | cie->initial_instructions = p + length; | |
794 | cie->augmentation++; | |
795 | } | |
796 | ||
797 | while (*cie->augmentation) { | |
798 | /* | |
799 | * "L" indicates a byte showing how the | |
800 | * LSDA pointer is encoded. Skip it. | |
801 | */ | |
802 | if (*cie->augmentation == 'L') { | |
803 | p++; | |
804 | cie->augmentation++; | |
805 | } else if (*cie->augmentation == 'R') { | |
806 | /* | |
807 | * "R" indicates a byte showing | |
808 | * how FDE addresses are | |
809 | * encoded. | |
810 | */ | |
811 | cie->encoding = *(char *)p++; | |
812 | cie->augmentation++; | |
813 | } else if (*cie->augmentation == 'P') { | |
814 | /* | |
815 | * "R" indicates a personality | |
816 | * routine in the CIE | |
817 | * augmentation. | |
818 | */ | |
b344e24a | 819 | UNWINDER_BUG(); |
bd353861 | 820 | } else if (*cie->augmentation == 'S') { |
b344e24a | 821 | UNWINDER_BUG(); |
bd353861 MF |
822 | } else { |
823 | /* | |
824 | * Unknown augmentation. Assume | |
825 | * 'z' augmentation. | |
826 | */ | |
827 | p = cie->initial_instructions; | |
b344e24a | 828 | UNWINDER_BUG_ON(!p); |
bd353861 MF |
829 | break; |
830 | } | |
831 | } | |
832 | ||
833 | cie->initial_instructions = p; | |
834 | cie->instructions_end = end; | |
835 | ||
836 | /* Add to list */ | |
837 | spin_lock_irqsave(&dwarf_cie_lock, flags); | |
858918b7 MF |
838 | |
839 | while (*rb_node) { | |
840 | struct dwarf_cie *cie_tmp; | |
841 | ||
842 | cie_tmp = rb_entry(*rb_node, struct dwarf_cie, node); | |
843 | ||
844 | parent = *rb_node; | |
845 | ||
846 | if (cie->cie_pointer < cie_tmp->cie_pointer) | |
847 | rb_node = &parent->rb_left; | |
848 | else if (cie->cie_pointer >= cie_tmp->cie_pointer) | |
849 | rb_node = &parent->rb_right; | |
850 | else | |
851 | WARN_ON(1); | |
852 | } | |
853 | ||
854 | rb_link_node(&cie->node, parent, rb_node); | |
855 | rb_insert_color(&cie->node, &cie_root); | |
856 | ||
d8252d62 | 857 | #ifdef CONFIG_MODULES |
858918b7 MF |
858 | if (mod != NULL) |
859 | list_add_tail(&cie->link, &mod->arch.cie_list); | |
d8252d62 | 860 | #endif |
858918b7 | 861 | |
bd353861 MF |
862 | spin_unlock_irqrestore(&dwarf_cie_lock, flags); |
863 | ||
864 | return 0; | |
865 | } | |
866 | ||
867 | static int dwarf_parse_fde(void *entry, u32 entry_type, | |
5480675d | 868 | void *start, unsigned long len, |
a6a2f2ad | 869 | unsigned char *end, struct module *mod) |
bd353861 | 870 | { |
858918b7 | 871 | struct rb_node **rb_node = &fde_root.rb_node; |
4e1a2594 | 872 | struct rb_node *parent = *rb_node; |
bd353861 MF |
873 | struct dwarf_fde *fde; |
874 | struct dwarf_cie *cie; | |
875 | unsigned long flags; | |
876 | int count; | |
877 | void *p = start; | |
878 | ||
879 | fde = kzalloc(sizeof(*fde), GFP_KERNEL); | |
880 | if (!fde) | |
881 | return -ENOMEM; | |
882 | ||
883 | fde->length = len; | |
884 | ||
885 | /* | |
886 | * In a .eh_frame section the CIE pointer is the | |
887 | * delta between the address within the FDE | |
888 | */ | |
889 | fde->cie_pointer = (unsigned long)(p - entry_type - 4); | |
890 | ||
891 | cie = dwarf_lookup_cie(fde->cie_pointer); | |
892 | fde->cie = cie; | |
893 | ||
894 | if (cie->encoding) | |
895 | count = dwarf_read_encoded_value(p, &fde->initial_location, | |
896 | cie->encoding); | |
897 | else | |
898 | count = dwarf_read_addr(p, &fde->initial_location); | |
899 | ||
900 | p += count; | |
901 | ||
902 | if (cie->encoding) | |
903 | count = dwarf_read_encoded_value(p, &fde->address_range, | |
904 | cie->encoding & 0x0f); | |
905 | else | |
906 | count = dwarf_read_addr(p, &fde->address_range); | |
907 | ||
908 | p += count; | |
909 | ||
910 | if (fde->cie->flags & DWARF_CIE_Z_AUGMENTATION) { | |
911 | unsigned int length; | |
912 | count = dwarf_read_uleb128(p, &length); | |
913 | p += count + length; | |
914 | } | |
915 | ||
916 | /* Call frame instructions. */ | |
917 | fde->instructions = p; | |
5480675d | 918 | fde->end = end; |
bd353861 MF |
919 | |
920 | /* Add to list. */ | |
921 | spin_lock_irqsave(&dwarf_fde_lock, flags); | |
858918b7 MF |
922 | |
923 | while (*rb_node) { | |
924 | struct dwarf_fde *fde_tmp; | |
925 | unsigned long tmp_start, tmp_end; | |
926 | unsigned long start, end; | |
927 | ||
928 | fde_tmp = rb_entry(*rb_node, struct dwarf_fde, node); | |
929 | ||
930 | start = fde->initial_location; | |
931 | end = fde->initial_location + fde->address_range; | |
932 | ||
933 | tmp_start = fde_tmp->initial_location; | |
934 | tmp_end = fde_tmp->initial_location + fde_tmp->address_range; | |
935 | ||
936 | parent = *rb_node; | |
937 | ||
938 | if (start < tmp_start) | |
939 | rb_node = &parent->rb_left; | |
940 | else if (start >= tmp_end) | |
941 | rb_node = &parent->rb_right; | |
942 | else | |
943 | WARN_ON(1); | |
944 | } | |
945 | ||
946 | rb_link_node(&fde->node, parent, rb_node); | |
947 | rb_insert_color(&fde->node, &fde_root); | |
948 | ||
d8252d62 | 949 | #ifdef CONFIG_MODULES |
858918b7 MF |
950 | if (mod != NULL) |
951 | list_add_tail(&fde->link, &mod->arch.fde_list); | |
d8252d62 | 952 | #endif |
858918b7 | 953 | |
bd353861 MF |
954 | spin_unlock_irqrestore(&dwarf_fde_lock, flags); |
955 | ||
956 | return 0; | |
957 | } | |
958 | ||
b344e24a MF |
959 | static void dwarf_unwinder_dump(struct task_struct *task, |
960 | struct pt_regs *regs, | |
bd353861 | 961 | unsigned long *sp, |
b344e24a MF |
962 | const struct stacktrace_ops *ops, |
963 | void *data) | |
bd353861 | 964 | { |
fb3f3e7f MF |
965 | struct dwarf_frame *frame, *_frame; |
966 | unsigned long return_addr; | |
967 | ||
968 | _frame = NULL; | |
969 | return_addr = 0; | |
bd353861 | 970 | |
fb3f3e7f MF |
971 | while (1) { |
972 | frame = dwarf_unwind_stack(return_addr, _frame); | |
973 | ||
ed4fe7f4 MF |
974 | if (_frame) |
975 | dwarf_free_frame(_frame); | |
fb3f3e7f MF |
976 | |
977 | _frame = frame; | |
978 | ||
979 | if (!frame || !frame->return_addr) | |
980 | break; | |
bd353861 | 981 | |
fb3f3e7f MF |
982 | return_addr = frame->return_addr; |
983 | ops->address(data, return_addr, 1); | |
bd353861 | 984 | } |
ed4fe7f4 MF |
985 | |
986 | if (frame) | |
987 | dwarf_free_frame(frame); | |
bd353861 MF |
988 | } |
989 | ||
990 | static struct unwinder dwarf_unwinder = { | |
991 | .name = "dwarf-unwinder", | |
992 | .dump = dwarf_unwinder_dump, | |
993 | .rating = 150, | |
994 | }; | |
995 | ||
996 | static void dwarf_unwinder_cleanup(void) | |
997 | { | |
e376ed7c CS |
998 | struct dwarf_fde *fde, *next_fde; |
999 | struct dwarf_cie *cie, *next_cie; | |
bd353861 MF |
1000 | |
1001 | /* | |
1002 | * Deallocate all the memory allocated for the DWARF unwinder. | |
1003 | * Traverse all the FDE/CIE lists and remove and free all the | |
1004 | * memory associated with those data structures. | |
1005 | */ | |
e376ed7c | 1006 | rbtree_postorder_for_each_entry_safe(fde, next_fde, &fde_root, node) |
bd353861 | 1007 | kfree(fde); |
858918b7 | 1008 | |
e376ed7c | 1009 | rbtree_postorder_for_each_entry_safe(cie, next_cie, &cie_root, node) |
858918b7 | 1010 | kfree(cie); |
fb3f3e7f MF |
1011 | |
1012 | kmem_cache_destroy(dwarf_reg_cachep); | |
1013 | kmem_cache_destroy(dwarf_frame_cachep); | |
bd353861 MF |
1014 | } |
1015 | ||
1016 | /** | |
a6a2f2ad MF |
1017 | * dwarf_parse_section - parse DWARF section |
1018 | * @eh_frame_start: start address of the .eh_frame section | |
1019 | * @eh_frame_end: end address of the .eh_frame section | |
1020 | * @mod: the kernel module containing the .eh_frame section | |
bd353861 | 1021 | * |
a6a2f2ad | 1022 | * Parse the information in a .eh_frame section. |
bd353861 | 1023 | */ |
5a3abba7 PM |
1024 | static int dwarf_parse_section(char *eh_frame_start, char *eh_frame_end, |
1025 | struct module *mod) | |
bd353861 MF |
1026 | { |
1027 | u32 entry_type; | |
1028 | void *p, *entry; | |
2f6dafc5 | 1029 | int count, err = 0; |
eca28e37 | 1030 | unsigned long len = 0; |
bd353861 MF |
1031 | unsigned int c_entries, f_entries; |
1032 | unsigned char *end; | |
bd353861 MF |
1033 | |
1034 | c_entries = 0; | |
1035 | f_entries = 0; | |
a6a2f2ad | 1036 | entry = eh_frame_start; |
fb3f3e7f | 1037 | |
a6a2f2ad | 1038 | while ((char *)entry < eh_frame_end) { |
bd353861 MF |
1039 | p = entry; |
1040 | ||
1041 | count = dwarf_entry_len(p, &len); | |
1042 | if (count == 0) { | |
1043 | /* | |
1044 | * We read a bogus length field value. There is | |
1045 | * nothing we can do here apart from disabling | |
1046 | * the DWARF unwinder. We can't even skip this | |
1047 | * entry and move to the next one because 'len' | |
1048 | * tells us where our next entry is. | |
1049 | */ | |
a6a2f2ad | 1050 | err = -EINVAL; |
bd353861 MF |
1051 | goto out; |
1052 | } else | |
1053 | p += count; | |
1054 | ||
1055 | /* initial length does not include itself */ | |
1056 | end = p + len; | |
1057 | ||
3497447f | 1058 | entry_type = get_unaligned((u32 *)p); |
bd353861 MF |
1059 | p += 4; |
1060 | ||
1061 | if (entry_type == DW_EH_FRAME_CIE) { | |
a6a2f2ad | 1062 | err = dwarf_parse_cie(entry, p, len, end, mod); |
bd353861 MF |
1063 | if (err < 0) |
1064 | goto out; | |
1065 | else | |
1066 | c_entries++; | |
1067 | } else { | |
a6a2f2ad MF |
1068 | err = dwarf_parse_fde(entry, entry_type, p, len, |
1069 | end, mod); | |
bd353861 MF |
1070 | if (err < 0) |
1071 | goto out; | |
1072 | else | |
1073 | f_entries++; | |
1074 | } | |
1075 | ||
1076 | entry = (char *)entry + len + 4; | |
1077 | } | |
1078 | ||
1079 | printk(KERN_INFO "DWARF unwinder initialised: read %u CIEs, %u FDEs\n", | |
1080 | c_entries, f_entries); | |
1081 | ||
a6a2f2ad MF |
1082 | return 0; |
1083 | ||
1084 | out: | |
1085 | return err; | |
1086 | } | |
1087 | ||
5a3abba7 PM |
1088 | #ifdef CONFIG_MODULES |
1089 | int module_dwarf_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, | |
1090 | struct module *me) | |
1091 | { | |
1092 | unsigned int i, err; | |
1093 | unsigned long start, end; | |
1094 | char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; | |
1095 | ||
1096 | start = end = 0; | |
1097 | ||
1098 | for (i = 1; i < hdr->e_shnum; i++) { | |
1099 | /* Alloc bit cleared means "ignore it." */ | |
1100 | if ((sechdrs[i].sh_flags & SHF_ALLOC) | |
1101 | && !strcmp(secstrings+sechdrs[i].sh_name, ".eh_frame")) { | |
1102 | start = sechdrs[i].sh_addr; | |
1103 | end = start + sechdrs[i].sh_size; | |
1104 | break; | |
1105 | } | |
1106 | } | |
1107 | ||
1108 | /* Did we find the .eh_frame section? */ | |
1109 | if (i != hdr->e_shnum) { | |
858918b7 MF |
1110 | INIT_LIST_HEAD(&me->arch.cie_list); |
1111 | INIT_LIST_HEAD(&me->arch.fde_list); | |
5a3abba7 PM |
1112 | err = dwarf_parse_section((char *)start, (char *)end, me); |
1113 | if (err) { | |
1114 | printk(KERN_WARNING "%s: failed to parse DWARF info\n", | |
1115 | me->name); | |
1116 | return err; | |
1117 | } | |
1118 | } | |
1119 | ||
1120 | return 0; | |
1121 | } | |
1122 | ||
a6a2f2ad | 1123 | /** |
5a3abba7 | 1124 | * module_dwarf_cleanup - remove FDE/CIEs associated with @mod |
a6a2f2ad MF |
1125 | * @mod: the module that is being unloaded |
1126 | * | |
1127 | * Remove any FDEs and CIEs from the global lists that came from | |
1128 | * @mod's .eh_frame section because @mod is being unloaded. | |
1129 | */ | |
5a3abba7 | 1130 | void module_dwarf_cleanup(struct module *mod) |
a6a2f2ad | 1131 | { |
858918b7 MF |
1132 | struct dwarf_fde *fde, *ftmp; |
1133 | struct dwarf_cie *cie, *ctmp; | |
a6a2f2ad MF |
1134 | unsigned long flags; |
1135 | ||
1136 | spin_lock_irqsave(&dwarf_cie_lock, flags); | |
1137 | ||
858918b7 | 1138 | list_for_each_entry_safe(cie, ctmp, &mod->arch.cie_list, link) { |
a6a2f2ad | 1139 | list_del(&cie->link); |
858918b7 | 1140 | rb_erase(&cie->node, &cie_root); |
a6a2f2ad | 1141 | kfree(cie); |
a6a2f2ad MF |
1142 | } |
1143 | ||
1144 | spin_unlock_irqrestore(&dwarf_cie_lock, flags); | |
1145 | ||
1146 | spin_lock_irqsave(&dwarf_fde_lock, flags); | |
1147 | ||
858918b7 | 1148 | list_for_each_entry_safe(fde, ftmp, &mod->arch.fde_list, link) { |
a6a2f2ad | 1149 | list_del(&fde->link); |
858918b7 | 1150 | rb_erase(&fde->node, &fde_root); |
a6a2f2ad | 1151 | kfree(fde); |
a6a2f2ad MF |
1152 | } |
1153 | ||
1154 | spin_unlock_irqrestore(&dwarf_fde_lock, flags); | |
1155 | } | |
5a3abba7 | 1156 | #endif /* CONFIG_MODULES */ |
a6a2f2ad MF |
1157 | |
1158 | /** | |
1159 | * dwarf_unwinder_init - initialise the dwarf unwinder | |
1160 | * | |
1161 | * Build the data structures describing the .dwarf_frame section to | |
1162 | * make it easier to lookup CIE and FDE entries. Because the | |
1163 | * .eh_frame section is packed as tightly as possible it is not | |
1164 | * easy to lookup the FDE for a given PC, so we build a list of FDE | |
1165 | * and CIE entries that make it easier. | |
1166 | */ | |
1167 | static int __init dwarf_unwinder_init(void) | |
1168 | { | |
8a37f520 | 1169 | int err = -ENOMEM; |
a6a2f2ad MF |
1170 | |
1171 | dwarf_frame_cachep = kmem_cache_create("dwarf_frames", | |
8ec006c5 PM |
1172 | sizeof(struct dwarf_frame), 0, |
1173 | SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL); | |
1174 | ||
a6a2f2ad | 1175 | dwarf_reg_cachep = kmem_cache_create("dwarf_regs", |
8ec006c5 PM |
1176 | sizeof(struct dwarf_reg), 0, |
1177 | SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL); | |
a6a2f2ad MF |
1178 | |
1179 | dwarf_frame_pool = mempool_create(DWARF_FRAME_MIN_REQ, | |
1180 | mempool_alloc_slab, | |
1181 | mempool_free_slab, | |
1182 | dwarf_frame_cachep); | |
8a37f520 PM |
1183 | if (!dwarf_frame_pool) |
1184 | goto out; | |
a6a2f2ad MF |
1185 | |
1186 | dwarf_reg_pool = mempool_create(DWARF_REG_MIN_REQ, | |
1187 | mempool_alloc_slab, | |
1188 | mempool_free_slab, | |
1189 | dwarf_reg_cachep); | |
8a37f520 PM |
1190 | if (!dwarf_reg_pool) |
1191 | goto out; | |
a6a2f2ad MF |
1192 | |
1193 | err = dwarf_parse_section(__start_eh_frame, __stop_eh_frame, NULL); | |
1194 | if (err) | |
1195 | goto out; | |
1196 | ||
bd353861 MF |
1197 | err = unwinder_register(&dwarf_unwinder); |
1198 | if (err) | |
1199 | goto out; | |
1200 | ||
8a37f520 PM |
1201 | dwarf_unwinder_ready = 1; |
1202 | ||
97f361e2 | 1203 | return 0; |
bd353861 MF |
1204 | |
1205 | out: | |
1206 | printk(KERN_ERR "Failed to initialise DWARF unwinder: %d\n", err); | |
1207 | dwarf_unwinder_cleanup(); | |
8a37f520 | 1208 | return err; |
bd353861 | 1209 | } |
97f361e2 | 1210 | early_initcall(dwarf_unwinder_init); |