Loading...
1/*
2 * fs/proc/vmcore.c Interface for accessing the crash
3 * dump from the system's previous life.
4 * Heavily borrowed from fs/proc/kcore.c
5 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
6 * Copyright (C) IBM Corporation, 2004. All rights reserved
7 *
8 */
9
10#include <linux/mm.h>
11#include <linux/proc_fs.h>
12#include <linux/user.h>
13#include <linux/elf.h>
14#include <linux/elfcore.h>
15#include <linux/slab.h>
16#include <linux/highmem.h>
17#include <linux/bootmem.h>
18#include <linux/init.h>
19#include <linux/crash_dump.h>
20#include <linux/list.h>
21#include <asm/uaccess.h>
22#include <asm/io.h>
23
24/* List representing chunks of contiguous memory areas and their offsets in
25 * vmcore file.
26 */
27static LIST_HEAD(vmcore_list);
28
29/* Stores the pointer to the buffer containing kernel elf core headers. */
30static char *elfcorebuf;
31static size_t elfcorebuf_sz;
32
33/* Total size of vmcore file. */
34static u64 vmcore_size;
35
36static struct proc_dir_entry *proc_vmcore = NULL;
37
38/*
39 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
40 * The called function has to take care of module refcounting.
41 */
42static int (*oldmem_pfn_is_ram)(unsigned long pfn);
43
44int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
45{
46 if (oldmem_pfn_is_ram)
47 return -EBUSY;
48 oldmem_pfn_is_ram = fn;
49 return 0;
50}
51EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
52
53void unregister_oldmem_pfn_is_ram(void)
54{
55 oldmem_pfn_is_ram = NULL;
56 wmb();
57}
58EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
59
60static int pfn_is_ram(unsigned long pfn)
61{
62 int (*fn)(unsigned long pfn);
63 /* pfn is ram unless fn() checks pagetype */
64 int ret = 1;
65
66 /*
67 * Ask hypervisor if the pfn is really ram.
68 * A ballooned page contains no data and reading from such a page
69 * will cause high load in the hypervisor.
70 */
71 fn = oldmem_pfn_is_ram;
72 if (fn)
73 ret = fn(pfn);
74
75 return ret;
76}
77
78/* Reads a page from the oldmem device from given offset. */
79static ssize_t read_from_oldmem(char *buf, size_t count,
80 u64 *ppos, int userbuf)
81{
82 unsigned long pfn, offset;
83 size_t nr_bytes;
84 ssize_t read = 0, tmp;
85
86 if (!count)
87 return 0;
88
89 offset = (unsigned long)(*ppos % PAGE_SIZE);
90 pfn = (unsigned long)(*ppos / PAGE_SIZE);
91
92 do {
93 if (count > (PAGE_SIZE - offset))
94 nr_bytes = PAGE_SIZE - offset;
95 else
96 nr_bytes = count;
97
98 /* If pfn is not ram, return zeros for sparse dump files */
99 if (pfn_is_ram(pfn) == 0)
100 memset(buf, 0, nr_bytes);
101 else {
102 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
103 offset, userbuf);
104 if (tmp < 0)
105 return tmp;
106 }
107 *ppos += nr_bytes;
108 count -= nr_bytes;
109 buf += nr_bytes;
110 read += nr_bytes;
111 ++pfn;
112 offset = 0;
113 } while (count);
114
115 return read;
116}
117
118/* Maps vmcore file offset to respective physical address in memroy. */
119static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
120 struct vmcore **m_ptr)
121{
122 struct vmcore *m;
123 u64 paddr;
124
125 list_for_each_entry(m, vc_list, list) {
126 u64 start, end;
127 start = m->offset;
128 end = m->offset + m->size - 1;
129 if (offset >= start && offset <= end) {
130 paddr = m->paddr + offset - start;
131 *m_ptr = m;
132 return paddr;
133 }
134 }
135 *m_ptr = NULL;
136 return 0;
137}
138
139/* Read from the ELF header and then the crash dump. On error, negative value is
140 * returned otherwise number of bytes read are returned.
141 */
142static ssize_t read_vmcore(struct file *file, char __user *buffer,
143 size_t buflen, loff_t *fpos)
144{
145 ssize_t acc = 0, tmp;
146 size_t tsz;
147 u64 start, nr_bytes;
148 struct vmcore *curr_m = NULL;
149
150 if (buflen == 0 || *fpos >= vmcore_size)
151 return 0;
152
153 /* trim buflen to not go beyond EOF */
154 if (buflen > vmcore_size - *fpos)
155 buflen = vmcore_size - *fpos;
156
157 /* Read ELF core header */
158 if (*fpos < elfcorebuf_sz) {
159 tsz = elfcorebuf_sz - *fpos;
160 if (buflen < tsz)
161 tsz = buflen;
162 if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
163 return -EFAULT;
164 buflen -= tsz;
165 *fpos += tsz;
166 buffer += tsz;
167 acc += tsz;
168
169 /* leave now if filled buffer already */
170 if (buflen == 0)
171 return acc;
172 }
173
174 start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
175 if (!curr_m)
176 return -EINVAL;
177 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
178 tsz = buflen;
179
180 /* Calculate left bytes in current memory segment. */
181 nr_bytes = (curr_m->size - (start - curr_m->paddr));
182 if (tsz > nr_bytes)
183 tsz = nr_bytes;
184
185 while (buflen) {
186 tmp = read_from_oldmem(buffer, tsz, &start, 1);
187 if (tmp < 0)
188 return tmp;
189 buflen -= tsz;
190 *fpos += tsz;
191 buffer += tsz;
192 acc += tsz;
193 if (start >= (curr_m->paddr + curr_m->size)) {
194 if (curr_m->list.next == &vmcore_list)
195 return acc; /*EOF*/
196 curr_m = list_entry(curr_m->list.next,
197 struct vmcore, list);
198 start = curr_m->paddr;
199 }
200 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
201 tsz = buflen;
202 /* Calculate left bytes in current memory segment. */
203 nr_bytes = (curr_m->size - (start - curr_m->paddr));
204 if (tsz > nr_bytes)
205 tsz = nr_bytes;
206 }
207 return acc;
208}
209
210static const struct file_operations proc_vmcore_operations = {
211 .read = read_vmcore,
212 .llseek = default_llseek,
213};
214
215static struct vmcore* __init get_new_element(void)
216{
217 return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
218}
219
220static u64 __init get_vmcore_size_elf64(char *elfptr)
221{
222 int i;
223 u64 size;
224 Elf64_Ehdr *ehdr_ptr;
225 Elf64_Phdr *phdr_ptr;
226
227 ehdr_ptr = (Elf64_Ehdr *)elfptr;
228 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
229 size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
230 for (i = 0; i < ehdr_ptr->e_phnum; i++) {
231 size += phdr_ptr->p_memsz;
232 phdr_ptr++;
233 }
234 return size;
235}
236
237static u64 __init get_vmcore_size_elf32(char *elfptr)
238{
239 int i;
240 u64 size;
241 Elf32_Ehdr *ehdr_ptr;
242 Elf32_Phdr *phdr_ptr;
243
244 ehdr_ptr = (Elf32_Ehdr *)elfptr;
245 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
246 size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
247 for (i = 0; i < ehdr_ptr->e_phnum; i++) {
248 size += phdr_ptr->p_memsz;
249 phdr_ptr++;
250 }
251 return size;
252}
253
254/* Merges all the PT_NOTE headers into one. */
255static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
256 struct list_head *vc_list)
257{
258 int i, nr_ptnote=0, rc=0;
259 char *tmp;
260 Elf64_Ehdr *ehdr_ptr;
261 Elf64_Phdr phdr, *phdr_ptr;
262 Elf64_Nhdr *nhdr_ptr;
263 u64 phdr_sz = 0, note_off;
264
265 ehdr_ptr = (Elf64_Ehdr *)elfptr;
266 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
267 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
268 int j;
269 void *notes_section;
270 struct vmcore *new;
271 u64 offset, max_sz, sz, real_sz = 0;
272 if (phdr_ptr->p_type != PT_NOTE)
273 continue;
274 nr_ptnote++;
275 max_sz = phdr_ptr->p_memsz;
276 offset = phdr_ptr->p_offset;
277 notes_section = kmalloc(max_sz, GFP_KERNEL);
278 if (!notes_section)
279 return -ENOMEM;
280 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
281 if (rc < 0) {
282 kfree(notes_section);
283 return rc;
284 }
285 nhdr_ptr = notes_section;
286 for (j = 0; j < max_sz; j += sz) {
287 if (nhdr_ptr->n_namesz == 0)
288 break;
289 sz = sizeof(Elf64_Nhdr) +
290 ((nhdr_ptr->n_namesz + 3) & ~3) +
291 ((nhdr_ptr->n_descsz + 3) & ~3);
292 real_sz += sz;
293 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
294 }
295
296 /* Add this contiguous chunk of notes section to vmcore list.*/
297 new = get_new_element();
298 if (!new) {
299 kfree(notes_section);
300 return -ENOMEM;
301 }
302 new->paddr = phdr_ptr->p_offset;
303 new->size = real_sz;
304 list_add_tail(&new->list, vc_list);
305 phdr_sz += real_sz;
306 kfree(notes_section);
307 }
308
309 /* Prepare merged PT_NOTE program header. */
310 phdr.p_type = PT_NOTE;
311 phdr.p_flags = 0;
312 note_off = sizeof(Elf64_Ehdr) +
313 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
314 phdr.p_offset = note_off;
315 phdr.p_vaddr = phdr.p_paddr = 0;
316 phdr.p_filesz = phdr.p_memsz = phdr_sz;
317 phdr.p_align = 0;
318
319 /* Add merged PT_NOTE program header*/
320 tmp = elfptr + sizeof(Elf64_Ehdr);
321 memcpy(tmp, &phdr, sizeof(phdr));
322 tmp += sizeof(phdr);
323
324 /* Remove unwanted PT_NOTE program headers. */
325 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
326 *elfsz = *elfsz - i;
327 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
328
329 /* Modify e_phnum to reflect merged headers. */
330 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
331
332 return 0;
333}
334
335/* Merges all the PT_NOTE headers into one. */
336static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
337 struct list_head *vc_list)
338{
339 int i, nr_ptnote=0, rc=0;
340 char *tmp;
341 Elf32_Ehdr *ehdr_ptr;
342 Elf32_Phdr phdr, *phdr_ptr;
343 Elf32_Nhdr *nhdr_ptr;
344 u64 phdr_sz = 0, note_off;
345
346 ehdr_ptr = (Elf32_Ehdr *)elfptr;
347 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
348 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
349 int j;
350 void *notes_section;
351 struct vmcore *new;
352 u64 offset, max_sz, sz, real_sz = 0;
353 if (phdr_ptr->p_type != PT_NOTE)
354 continue;
355 nr_ptnote++;
356 max_sz = phdr_ptr->p_memsz;
357 offset = phdr_ptr->p_offset;
358 notes_section = kmalloc(max_sz, GFP_KERNEL);
359 if (!notes_section)
360 return -ENOMEM;
361 rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
362 if (rc < 0) {
363 kfree(notes_section);
364 return rc;
365 }
366 nhdr_ptr = notes_section;
367 for (j = 0; j < max_sz; j += sz) {
368 if (nhdr_ptr->n_namesz == 0)
369 break;
370 sz = sizeof(Elf32_Nhdr) +
371 ((nhdr_ptr->n_namesz + 3) & ~3) +
372 ((nhdr_ptr->n_descsz + 3) & ~3);
373 real_sz += sz;
374 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
375 }
376
377 /* Add this contiguous chunk of notes section to vmcore list.*/
378 new = get_new_element();
379 if (!new) {
380 kfree(notes_section);
381 return -ENOMEM;
382 }
383 new->paddr = phdr_ptr->p_offset;
384 new->size = real_sz;
385 list_add_tail(&new->list, vc_list);
386 phdr_sz += real_sz;
387 kfree(notes_section);
388 }
389
390 /* Prepare merged PT_NOTE program header. */
391 phdr.p_type = PT_NOTE;
392 phdr.p_flags = 0;
393 note_off = sizeof(Elf32_Ehdr) +
394 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
395 phdr.p_offset = note_off;
396 phdr.p_vaddr = phdr.p_paddr = 0;
397 phdr.p_filesz = phdr.p_memsz = phdr_sz;
398 phdr.p_align = 0;
399
400 /* Add merged PT_NOTE program header*/
401 tmp = elfptr + sizeof(Elf32_Ehdr);
402 memcpy(tmp, &phdr, sizeof(phdr));
403 tmp += sizeof(phdr);
404
405 /* Remove unwanted PT_NOTE program headers. */
406 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
407 *elfsz = *elfsz - i;
408 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
409
410 /* Modify e_phnum to reflect merged headers. */
411 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
412
413 return 0;
414}
415
416/* Add memory chunks represented by program headers to vmcore list. Also update
417 * the new offset fields of exported program headers. */
418static int __init process_ptload_program_headers_elf64(char *elfptr,
419 size_t elfsz,
420 struct list_head *vc_list)
421{
422 int i;
423 Elf64_Ehdr *ehdr_ptr;
424 Elf64_Phdr *phdr_ptr;
425 loff_t vmcore_off;
426 struct vmcore *new;
427
428 ehdr_ptr = (Elf64_Ehdr *)elfptr;
429 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
430
431 /* First program header is PT_NOTE header. */
432 vmcore_off = sizeof(Elf64_Ehdr) +
433 (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
434 phdr_ptr->p_memsz; /* Note sections */
435
436 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
437 if (phdr_ptr->p_type != PT_LOAD)
438 continue;
439
440 /* Add this contiguous chunk of memory to vmcore list.*/
441 new = get_new_element();
442 if (!new)
443 return -ENOMEM;
444 new->paddr = phdr_ptr->p_offset;
445 new->size = phdr_ptr->p_memsz;
446 list_add_tail(&new->list, vc_list);
447
448 /* Update the program header offset. */
449 phdr_ptr->p_offset = vmcore_off;
450 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
451 }
452 return 0;
453}
454
455static int __init process_ptload_program_headers_elf32(char *elfptr,
456 size_t elfsz,
457 struct list_head *vc_list)
458{
459 int i;
460 Elf32_Ehdr *ehdr_ptr;
461 Elf32_Phdr *phdr_ptr;
462 loff_t vmcore_off;
463 struct vmcore *new;
464
465 ehdr_ptr = (Elf32_Ehdr *)elfptr;
466 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
467
468 /* First program header is PT_NOTE header. */
469 vmcore_off = sizeof(Elf32_Ehdr) +
470 (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
471 phdr_ptr->p_memsz; /* Note sections */
472
473 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
474 if (phdr_ptr->p_type != PT_LOAD)
475 continue;
476
477 /* Add this contiguous chunk of memory to vmcore list.*/
478 new = get_new_element();
479 if (!new)
480 return -ENOMEM;
481 new->paddr = phdr_ptr->p_offset;
482 new->size = phdr_ptr->p_memsz;
483 list_add_tail(&new->list, vc_list);
484
485 /* Update the program header offset */
486 phdr_ptr->p_offset = vmcore_off;
487 vmcore_off = vmcore_off + phdr_ptr->p_memsz;
488 }
489 return 0;
490}
491
492/* Sets offset fields of vmcore elements. */
493static void __init set_vmcore_list_offsets_elf64(char *elfptr,
494 struct list_head *vc_list)
495{
496 loff_t vmcore_off;
497 Elf64_Ehdr *ehdr_ptr;
498 struct vmcore *m;
499
500 ehdr_ptr = (Elf64_Ehdr *)elfptr;
501
502 /* Skip Elf header and program headers. */
503 vmcore_off = sizeof(Elf64_Ehdr) +
504 (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
505
506 list_for_each_entry(m, vc_list, list) {
507 m->offset = vmcore_off;
508 vmcore_off += m->size;
509 }
510}
511
512/* Sets offset fields of vmcore elements. */
513static void __init set_vmcore_list_offsets_elf32(char *elfptr,
514 struct list_head *vc_list)
515{
516 loff_t vmcore_off;
517 Elf32_Ehdr *ehdr_ptr;
518 struct vmcore *m;
519
520 ehdr_ptr = (Elf32_Ehdr *)elfptr;
521
522 /* Skip Elf header and program headers. */
523 vmcore_off = sizeof(Elf32_Ehdr) +
524 (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
525
526 list_for_each_entry(m, vc_list, list) {
527 m->offset = vmcore_off;
528 vmcore_off += m->size;
529 }
530}
531
532static int __init parse_crash_elf64_headers(void)
533{
534 int rc=0;
535 Elf64_Ehdr ehdr;
536 u64 addr;
537
538 addr = elfcorehdr_addr;
539
540 /* Read Elf header */
541 rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
542 if (rc < 0)
543 return rc;
544
545 /* Do some basic Verification. */
546 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
547 (ehdr.e_type != ET_CORE) ||
548 !vmcore_elf64_check_arch(&ehdr) ||
549 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
550 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
551 ehdr.e_version != EV_CURRENT ||
552 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
553 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
554 ehdr.e_phnum == 0) {
555 printk(KERN_WARNING "Warning: Core image elf header is not"
556 "sane\n");
557 return -EINVAL;
558 }
559
560 /* Read in all elf headers. */
561 elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
562 elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
563 if (!elfcorebuf)
564 return -ENOMEM;
565 addr = elfcorehdr_addr;
566 rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
567 if (rc < 0) {
568 kfree(elfcorebuf);
569 return rc;
570 }
571
572 /* Merge all PT_NOTE headers into one. */
573 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
574 if (rc) {
575 kfree(elfcorebuf);
576 return rc;
577 }
578 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
579 &vmcore_list);
580 if (rc) {
581 kfree(elfcorebuf);
582 return rc;
583 }
584 set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
585 return 0;
586}
587
588static int __init parse_crash_elf32_headers(void)
589{
590 int rc=0;
591 Elf32_Ehdr ehdr;
592 u64 addr;
593
594 addr = elfcorehdr_addr;
595
596 /* Read Elf header */
597 rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
598 if (rc < 0)
599 return rc;
600
601 /* Do some basic Verification. */
602 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
603 (ehdr.e_type != ET_CORE) ||
604 !elf_check_arch(&ehdr) ||
605 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
606 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
607 ehdr.e_version != EV_CURRENT ||
608 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
609 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
610 ehdr.e_phnum == 0) {
611 printk(KERN_WARNING "Warning: Core image elf header is not"
612 "sane\n");
613 return -EINVAL;
614 }
615
616 /* Read in all elf headers. */
617 elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
618 elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
619 if (!elfcorebuf)
620 return -ENOMEM;
621 addr = elfcorehdr_addr;
622 rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
623 if (rc < 0) {
624 kfree(elfcorebuf);
625 return rc;
626 }
627
628 /* Merge all PT_NOTE headers into one. */
629 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
630 if (rc) {
631 kfree(elfcorebuf);
632 return rc;
633 }
634 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
635 &vmcore_list);
636 if (rc) {
637 kfree(elfcorebuf);
638 return rc;
639 }
640 set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
641 return 0;
642}
643
644static int __init parse_crash_elf_headers(void)
645{
646 unsigned char e_ident[EI_NIDENT];
647 u64 addr;
648 int rc=0;
649
650 addr = elfcorehdr_addr;
651 rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
652 if (rc < 0)
653 return rc;
654 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
655 printk(KERN_WARNING "Warning: Core image elf header"
656 " not found\n");
657 return -EINVAL;
658 }
659
660 if (e_ident[EI_CLASS] == ELFCLASS64) {
661 rc = parse_crash_elf64_headers();
662 if (rc)
663 return rc;
664
665 /* Determine vmcore size. */
666 vmcore_size = get_vmcore_size_elf64(elfcorebuf);
667 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
668 rc = parse_crash_elf32_headers();
669 if (rc)
670 return rc;
671
672 /* Determine vmcore size. */
673 vmcore_size = get_vmcore_size_elf32(elfcorebuf);
674 } else {
675 printk(KERN_WARNING "Warning: Core image elf header is not"
676 " sane\n");
677 return -EINVAL;
678 }
679 return 0;
680}
681
682/* Init function for vmcore module. */
683static int __init vmcore_init(void)
684{
685 int rc = 0;
686
687 /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
688 if (!(is_vmcore_usable()))
689 return rc;
690 rc = parse_crash_elf_headers();
691 if (rc) {
692 printk(KERN_WARNING "Kdump: vmcore not initialized\n");
693 return rc;
694 }
695
696 proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
697 if (proc_vmcore)
698 proc_vmcore->size = vmcore_size;
699 return 0;
700}
701module_init(vmcore_init)
1/*
2 * fs/proc/vmcore.c Interface for accessing the crash
3 * dump from the system's previous life.
4 * Heavily borrowed from fs/proc/kcore.c
5 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
6 * Copyright (C) IBM Corporation, 2004. All rights reserved
7 *
8 */
9
10#include <linux/mm.h>
11#include <linux/kcore.h>
12#include <linux/user.h>
13#include <linux/elf.h>
14#include <linux/elfcore.h>
15#include <linux/export.h>
16#include <linux/slab.h>
17#include <linux/highmem.h>
18#include <linux/printk.h>
19#include <linux/bootmem.h>
20#include <linux/init.h>
21#include <linux/crash_dump.h>
22#include <linux/list.h>
23#include <linux/vmalloc.h>
24#include <linux/pagemap.h>
25#include <asm/uaccess.h>
26#include <asm/io.h>
27#include "internal.h"
28
29/* List representing chunks of contiguous memory areas and their offsets in
30 * vmcore file.
31 */
32static LIST_HEAD(vmcore_list);
33
34/* Stores the pointer to the buffer containing kernel elf core headers. */
35static char *elfcorebuf;
36static size_t elfcorebuf_sz;
37static size_t elfcorebuf_sz_orig;
38
39static char *elfnotes_buf;
40static size_t elfnotes_sz;
41
42/* Total size of vmcore file. */
43static u64 vmcore_size;
44
45static struct proc_dir_entry *proc_vmcore = NULL;
46
47/*
48 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
49 * The called function has to take care of module refcounting.
50 */
51static int (*oldmem_pfn_is_ram)(unsigned long pfn);
52
53int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
54{
55 if (oldmem_pfn_is_ram)
56 return -EBUSY;
57 oldmem_pfn_is_ram = fn;
58 return 0;
59}
60EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
61
62void unregister_oldmem_pfn_is_ram(void)
63{
64 oldmem_pfn_is_ram = NULL;
65 wmb();
66}
67EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
68
69static int pfn_is_ram(unsigned long pfn)
70{
71 int (*fn)(unsigned long pfn);
72 /* pfn is ram unless fn() checks pagetype */
73 int ret = 1;
74
75 /*
76 * Ask hypervisor if the pfn is really ram.
77 * A ballooned page contains no data and reading from such a page
78 * will cause high load in the hypervisor.
79 */
80 fn = oldmem_pfn_is_ram;
81 if (fn)
82 ret = fn(pfn);
83
84 return ret;
85}
86
87/* Reads a page from the oldmem device from given offset. */
88static ssize_t read_from_oldmem(char *buf, size_t count,
89 u64 *ppos, int userbuf)
90{
91 unsigned long pfn, offset;
92 size_t nr_bytes;
93 ssize_t read = 0, tmp;
94
95 if (!count)
96 return 0;
97
98 offset = (unsigned long)(*ppos % PAGE_SIZE);
99 pfn = (unsigned long)(*ppos / PAGE_SIZE);
100
101 do {
102 if (count > (PAGE_SIZE - offset))
103 nr_bytes = PAGE_SIZE - offset;
104 else
105 nr_bytes = count;
106
107 /* If pfn is not ram, return zeros for sparse dump files */
108 if (pfn_is_ram(pfn) == 0)
109 memset(buf, 0, nr_bytes);
110 else {
111 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
112 offset, userbuf);
113 if (tmp < 0)
114 return tmp;
115 }
116 *ppos += nr_bytes;
117 count -= nr_bytes;
118 buf += nr_bytes;
119 read += nr_bytes;
120 ++pfn;
121 offset = 0;
122 } while (count);
123
124 return read;
125}
126
127/*
128 * Architectures may override this function to allocate ELF header in 2nd kernel
129 */
130int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
131{
132 return 0;
133}
134
135/*
136 * Architectures may override this function to free header
137 */
138void __weak elfcorehdr_free(unsigned long long addr)
139{}
140
141/*
142 * Architectures may override this function to read from ELF header
143 */
144ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
145{
146 return read_from_oldmem(buf, count, ppos, 0);
147}
148
149/*
150 * Architectures may override this function to read from notes sections
151 */
152ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
153{
154 return read_from_oldmem(buf, count, ppos, 0);
155}
156
157/*
158 * Architectures may override this function to map oldmem
159 */
160int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
161 unsigned long from, unsigned long pfn,
162 unsigned long size, pgprot_t prot)
163{
164 return remap_pfn_range(vma, from, pfn, size, prot);
165}
166
167/*
168 * Copy to either kernel or user space
169 */
170static int copy_to(void *target, void *src, size_t size, int userbuf)
171{
172 if (userbuf) {
173 if (copy_to_user((char __user *) target, src, size))
174 return -EFAULT;
175 } else {
176 memcpy(target, src, size);
177 }
178 return 0;
179}
180
181/* Read from the ELF header and then the crash dump. On error, negative value is
182 * returned otherwise number of bytes read are returned.
183 */
184static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
185 int userbuf)
186{
187 ssize_t acc = 0, tmp;
188 size_t tsz;
189 u64 start;
190 struct vmcore *m = NULL;
191
192 if (buflen == 0 || *fpos >= vmcore_size)
193 return 0;
194
195 /* trim buflen to not go beyond EOF */
196 if (buflen > vmcore_size - *fpos)
197 buflen = vmcore_size - *fpos;
198
199 /* Read ELF core header */
200 if (*fpos < elfcorebuf_sz) {
201 tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
202 if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
203 return -EFAULT;
204 buflen -= tsz;
205 *fpos += tsz;
206 buffer += tsz;
207 acc += tsz;
208
209 /* leave now if filled buffer already */
210 if (buflen == 0)
211 return acc;
212 }
213
214 /* Read Elf note segment */
215 if (*fpos < elfcorebuf_sz + elfnotes_sz) {
216 void *kaddr;
217
218 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
219 kaddr = elfnotes_buf + *fpos - elfcorebuf_sz;
220 if (copy_to(buffer, kaddr, tsz, userbuf))
221 return -EFAULT;
222 buflen -= tsz;
223 *fpos += tsz;
224 buffer += tsz;
225 acc += tsz;
226
227 /* leave now if filled buffer already */
228 if (buflen == 0)
229 return acc;
230 }
231
232 list_for_each_entry(m, &vmcore_list, list) {
233 if (*fpos < m->offset + m->size) {
234 tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
235 start = m->paddr + *fpos - m->offset;
236 tmp = read_from_oldmem(buffer, tsz, &start, userbuf);
237 if (tmp < 0)
238 return tmp;
239 buflen -= tsz;
240 *fpos += tsz;
241 buffer += tsz;
242 acc += tsz;
243
244 /* leave now if filled buffer already */
245 if (buflen == 0)
246 return acc;
247 }
248 }
249
250 return acc;
251}
252
253static ssize_t read_vmcore(struct file *file, char __user *buffer,
254 size_t buflen, loff_t *fpos)
255{
256 return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
257}
258
259/*
260 * The vmcore fault handler uses the page cache and fills data using the
261 * standard __vmcore_read() function.
262 *
263 * On s390 the fault handler is used for memory regions that can't be mapped
264 * directly with remap_pfn_range().
265 */
266static int mmap_vmcore_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
267{
268#ifdef CONFIG_S390
269 struct address_space *mapping = vma->vm_file->f_mapping;
270 pgoff_t index = vmf->pgoff;
271 struct page *page;
272 loff_t offset;
273 char *buf;
274 int rc;
275
276 page = find_or_create_page(mapping, index, GFP_KERNEL);
277 if (!page)
278 return VM_FAULT_OOM;
279 if (!PageUptodate(page)) {
280 offset = (loff_t) index << PAGE_CACHE_SHIFT;
281 buf = __va((page_to_pfn(page) << PAGE_SHIFT));
282 rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
283 if (rc < 0) {
284 unlock_page(page);
285 page_cache_release(page);
286 return (rc == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
287 }
288 SetPageUptodate(page);
289 }
290 unlock_page(page);
291 vmf->page = page;
292 return 0;
293#else
294 return VM_FAULT_SIGBUS;
295#endif
296}
297
298static const struct vm_operations_struct vmcore_mmap_ops = {
299 .fault = mmap_vmcore_fault,
300};
301
302/**
303 * alloc_elfnotes_buf - allocate buffer for ELF note segment in
304 * vmalloc memory
305 *
306 * @notes_sz: size of buffer
307 *
308 * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
309 * the buffer to user-space by means of remap_vmalloc_range().
310 *
311 * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
312 * disabled and there's no need to allow users to mmap the buffer.
313 */
314static inline char *alloc_elfnotes_buf(size_t notes_sz)
315{
316#ifdef CONFIG_MMU
317 return vmalloc_user(notes_sz);
318#else
319 return vzalloc(notes_sz);
320#endif
321}
322
323/*
324 * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
325 * essential for mmap_vmcore() in order to map physically
326 * non-contiguous objects (ELF header, ELF note segment and memory
327 * regions in the 1st kernel pointed to by PT_LOAD entries) into
328 * virtually contiguous user-space in ELF layout.
329 */
330#ifdef CONFIG_MMU
331static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
332{
333 size_t size = vma->vm_end - vma->vm_start;
334 u64 start, end, len, tsz;
335 struct vmcore *m;
336
337 start = (u64)vma->vm_pgoff << PAGE_SHIFT;
338 end = start + size;
339
340 if (size > vmcore_size || end > vmcore_size)
341 return -EINVAL;
342
343 if (vma->vm_flags & (VM_WRITE | VM_EXEC))
344 return -EPERM;
345
346 vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
347 vma->vm_flags |= VM_MIXEDMAP;
348 vma->vm_ops = &vmcore_mmap_ops;
349
350 len = 0;
351
352 if (start < elfcorebuf_sz) {
353 u64 pfn;
354
355 tsz = min(elfcorebuf_sz - (size_t)start, size);
356 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
357 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
358 vma->vm_page_prot))
359 return -EAGAIN;
360 size -= tsz;
361 start += tsz;
362 len += tsz;
363
364 if (size == 0)
365 return 0;
366 }
367
368 if (start < elfcorebuf_sz + elfnotes_sz) {
369 void *kaddr;
370
371 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
372 kaddr = elfnotes_buf + start - elfcorebuf_sz;
373 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
374 kaddr, tsz))
375 goto fail;
376 size -= tsz;
377 start += tsz;
378 len += tsz;
379
380 if (size == 0)
381 return 0;
382 }
383
384 list_for_each_entry(m, &vmcore_list, list) {
385 if (start < m->offset + m->size) {
386 u64 paddr = 0;
387
388 tsz = min_t(size_t, m->offset + m->size - start, size);
389 paddr = m->paddr + start - m->offset;
390 if (remap_oldmem_pfn_range(vma, vma->vm_start + len,
391 paddr >> PAGE_SHIFT, tsz,
392 vma->vm_page_prot))
393 goto fail;
394 size -= tsz;
395 start += tsz;
396 len += tsz;
397
398 if (size == 0)
399 return 0;
400 }
401 }
402
403 return 0;
404fail:
405 do_munmap(vma->vm_mm, vma->vm_start, len);
406 return -EAGAIN;
407}
408#else
409static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
410{
411 return -ENOSYS;
412}
413#endif
414
415static const struct file_operations proc_vmcore_operations = {
416 .read = read_vmcore,
417 .llseek = default_llseek,
418 .mmap = mmap_vmcore,
419};
420
421static struct vmcore* __init get_new_element(void)
422{
423 return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
424}
425
426static u64 __init get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
427 struct list_head *vc_list)
428{
429 u64 size;
430 struct vmcore *m;
431
432 size = elfsz + elfnotesegsz;
433 list_for_each_entry(m, vc_list, list) {
434 size += m->size;
435 }
436 return size;
437}
438
439/**
440 * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
441 *
442 * @ehdr_ptr: ELF header
443 *
444 * This function updates p_memsz member of each PT_NOTE entry in the
445 * program header table pointed to by @ehdr_ptr to real size of ELF
446 * note segment.
447 */
448static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
449{
450 int i, rc=0;
451 Elf64_Phdr *phdr_ptr;
452 Elf64_Nhdr *nhdr_ptr;
453
454 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
455 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
456 void *notes_section;
457 u64 offset, max_sz, sz, real_sz = 0;
458 if (phdr_ptr->p_type != PT_NOTE)
459 continue;
460 max_sz = phdr_ptr->p_memsz;
461 offset = phdr_ptr->p_offset;
462 notes_section = kmalloc(max_sz, GFP_KERNEL);
463 if (!notes_section)
464 return -ENOMEM;
465 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
466 if (rc < 0) {
467 kfree(notes_section);
468 return rc;
469 }
470 nhdr_ptr = notes_section;
471 while (nhdr_ptr->n_namesz != 0) {
472 sz = sizeof(Elf64_Nhdr) +
473 ((nhdr_ptr->n_namesz + 3) & ~3) +
474 ((nhdr_ptr->n_descsz + 3) & ~3);
475 if ((real_sz + sz) > max_sz) {
476 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
477 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
478 break;
479 }
480 real_sz += sz;
481 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
482 }
483 kfree(notes_section);
484 phdr_ptr->p_memsz = real_sz;
485 if (real_sz == 0) {
486 pr_warn("Warning: Zero PT_NOTE entries found\n");
487 }
488 }
489
490 return 0;
491}
492
493/**
494 * get_note_number_and_size_elf64 - get the number of PT_NOTE program
495 * headers and sum of real size of their ELF note segment headers and
496 * data.
497 *
498 * @ehdr_ptr: ELF header
499 * @nr_ptnote: buffer for the number of PT_NOTE program headers
500 * @sz_ptnote: buffer for size of unique PT_NOTE program header
501 *
502 * This function is used to merge multiple PT_NOTE program headers
503 * into a unique single one. The resulting unique entry will have
504 * @sz_ptnote in its phdr->p_mem.
505 *
506 * It is assumed that program headers with PT_NOTE type pointed to by
507 * @ehdr_ptr has already been updated by update_note_header_size_elf64
508 * and each of PT_NOTE program headers has actual ELF note segment
509 * size in its p_memsz member.
510 */
511static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
512 int *nr_ptnote, u64 *sz_ptnote)
513{
514 int i;
515 Elf64_Phdr *phdr_ptr;
516
517 *nr_ptnote = *sz_ptnote = 0;
518
519 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
520 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
521 if (phdr_ptr->p_type != PT_NOTE)
522 continue;
523 *nr_ptnote += 1;
524 *sz_ptnote += phdr_ptr->p_memsz;
525 }
526
527 return 0;
528}
529
530/**
531 * copy_notes_elf64 - copy ELF note segments in a given buffer
532 *
533 * @ehdr_ptr: ELF header
534 * @notes_buf: buffer into which ELF note segments are copied
535 *
536 * This function is used to copy ELF note segment in the 1st kernel
537 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
538 * size of the buffer @notes_buf is equal to or larger than sum of the
539 * real ELF note segment headers and data.
540 *
541 * It is assumed that program headers with PT_NOTE type pointed to by
542 * @ehdr_ptr has already been updated by update_note_header_size_elf64
543 * and each of PT_NOTE program headers has actual ELF note segment
544 * size in its p_memsz member.
545 */
546static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
547{
548 int i, rc=0;
549 Elf64_Phdr *phdr_ptr;
550
551 phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
552
553 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
554 u64 offset;
555 if (phdr_ptr->p_type != PT_NOTE)
556 continue;
557 offset = phdr_ptr->p_offset;
558 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
559 &offset);
560 if (rc < 0)
561 return rc;
562 notes_buf += phdr_ptr->p_memsz;
563 }
564
565 return 0;
566}
567
568/* Merges all the PT_NOTE headers into one. */
569static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
570 char **notes_buf, size_t *notes_sz)
571{
572 int i, nr_ptnote=0, rc=0;
573 char *tmp;
574 Elf64_Ehdr *ehdr_ptr;
575 Elf64_Phdr phdr;
576 u64 phdr_sz = 0, note_off;
577
578 ehdr_ptr = (Elf64_Ehdr *)elfptr;
579
580 rc = update_note_header_size_elf64(ehdr_ptr);
581 if (rc < 0)
582 return rc;
583
584 rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
585 if (rc < 0)
586 return rc;
587
588 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
589 *notes_buf = alloc_elfnotes_buf(*notes_sz);
590 if (!*notes_buf)
591 return -ENOMEM;
592
593 rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
594 if (rc < 0)
595 return rc;
596
597 /* Prepare merged PT_NOTE program header. */
598 phdr.p_type = PT_NOTE;
599 phdr.p_flags = 0;
600 note_off = sizeof(Elf64_Ehdr) +
601 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
602 phdr.p_offset = roundup(note_off, PAGE_SIZE);
603 phdr.p_vaddr = phdr.p_paddr = 0;
604 phdr.p_filesz = phdr.p_memsz = phdr_sz;
605 phdr.p_align = 0;
606
607 /* Add merged PT_NOTE program header*/
608 tmp = elfptr + sizeof(Elf64_Ehdr);
609 memcpy(tmp, &phdr, sizeof(phdr));
610 tmp += sizeof(phdr);
611
612 /* Remove unwanted PT_NOTE program headers. */
613 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
614 *elfsz = *elfsz - i;
615 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
616 memset(elfptr + *elfsz, 0, i);
617 *elfsz = roundup(*elfsz, PAGE_SIZE);
618
619 /* Modify e_phnum to reflect merged headers. */
620 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
621
622 return 0;
623}
624
625/**
626 * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
627 *
628 * @ehdr_ptr: ELF header
629 *
630 * This function updates p_memsz member of each PT_NOTE entry in the
631 * program header table pointed to by @ehdr_ptr to real size of ELF
632 * note segment.
633 */
634static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
635{
636 int i, rc=0;
637 Elf32_Phdr *phdr_ptr;
638 Elf32_Nhdr *nhdr_ptr;
639
640 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
641 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
642 void *notes_section;
643 u64 offset, max_sz, sz, real_sz = 0;
644 if (phdr_ptr->p_type != PT_NOTE)
645 continue;
646 max_sz = phdr_ptr->p_memsz;
647 offset = phdr_ptr->p_offset;
648 notes_section = kmalloc(max_sz, GFP_KERNEL);
649 if (!notes_section)
650 return -ENOMEM;
651 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
652 if (rc < 0) {
653 kfree(notes_section);
654 return rc;
655 }
656 nhdr_ptr = notes_section;
657 while (nhdr_ptr->n_namesz != 0) {
658 sz = sizeof(Elf32_Nhdr) +
659 ((nhdr_ptr->n_namesz + 3) & ~3) +
660 ((nhdr_ptr->n_descsz + 3) & ~3);
661 if ((real_sz + sz) > max_sz) {
662 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
663 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
664 break;
665 }
666 real_sz += sz;
667 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
668 }
669 kfree(notes_section);
670 phdr_ptr->p_memsz = real_sz;
671 if (real_sz == 0) {
672 pr_warn("Warning: Zero PT_NOTE entries found\n");
673 }
674 }
675
676 return 0;
677}
678
679/**
680 * get_note_number_and_size_elf32 - get the number of PT_NOTE program
681 * headers and sum of real size of their ELF note segment headers and
682 * data.
683 *
684 * @ehdr_ptr: ELF header
685 * @nr_ptnote: buffer for the number of PT_NOTE program headers
686 * @sz_ptnote: buffer for size of unique PT_NOTE program header
687 *
688 * This function is used to merge multiple PT_NOTE program headers
689 * into a unique single one. The resulting unique entry will have
690 * @sz_ptnote in its phdr->p_mem.
691 *
692 * It is assumed that program headers with PT_NOTE type pointed to by
693 * @ehdr_ptr has already been updated by update_note_header_size_elf32
694 * and each of PT_NOTE program headers has actual ELF note segment
695 * size in its p_memsz member.
696 */
697static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
698 int *nr_ptnote, u64 *sz_ptnote)
699{
700 int i;
701 Elf32_Phdr *phdr_ptr;
702
703 *nr_ptnote = *sz_ptnote = 0;
704
705 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
706 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
707 if (phdr_ptr->p_type != PT_NOTE)
708 continue;
709 *nr_ptnote += 1;
710 *sz_ptnote += phdr_ptr->p_memsz;
711 }
712
713 return 0;
714}
715
716/**
717 * copy_notes_elf32 - copy ELF note segments in a given buffer
718 *
719 * @ehdr_ptr: ELF header
720 * @notes_buf: buffer into which ELF note segments are copied
721 *
722 * This function is used to copy ELF note segment in the 1st kernel
723 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
724 * size of the buffer @notes_buf is equal to or larger than sum of the
725 * real ELF note segment headers and data.
726 *
727 * It is assumed that program headers with PT_NOTE type pointed to by
728 * @ehdr_ptr has already been updated by update_note_header_size_elf32
729 * and each of PT_NOTE program headers has actual ELF note segment
730 * size in its p_memsz member.
731 */
732static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
733{
734 int i, rc=0;
735 Elf32_Phdr *phdr_ptr;
736
737 phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
738
739 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
740 u64 offset;
741 if (phdr_ptr->p_type != PT_NOTE)
742 continue;
743 offset = phdr_ptr->p_offset;
744 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
745 &offset);
746 if (rc < 0)
747 return rc;
748 notes_buf += phdr_ptr->p_memsz;
749 }
750
751 return 0;
752}
753
754/* Merges all the PT_NOTE headers into one. */
755static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
756 char **notes_buf, size_t *notes_sz)
757{
758 int i, nr_ptnote=0, rc=0;
759 char *tmp;
760 Elf32_Ehdr *ehdr_ptr;
761 Elf32_Phdr phdr;
762 u64 phdr_sz = 0, note_off;
763
764 ehdr_ptr = (Elf32_Ehdr *)elfptr;
765
766 rc = update_note_header_size_elf32(ehdr_ptr);
767 if (rc < 0)
768 return rc;
769
770 rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
771 if (rc < 0)
772 return rc;
773
774 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
775 *notes_buf = alloc_elfnotes_buf(*notes_sz);
776 if (!*notes_buf)
777 return -ENOMEM;
778
779 rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
780 if (rc < 0)
781 return rc;
782
783 /* Prepare merged PT_NOTE program header. */
784 phdr.p_type = PT_NOTE;
785 phdr.p_flags = 0;
786 note_off = sizeof(Elf32_Ehdr) +
787 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
788 phdr.p_offset = roundup(note_off, PAGE_SIZE);
789 phdr.p_vaddr = phdr.p_paddr = 0;
790 phdr.p_filesz = phdr.p_memsz = phdr_sz;
791 phdr.p_align = 0;
792
793 /* Add merged PT_NOTE program header*/
794 tmp = elfptr + sizeof(Elf32_Ehdr);
795 memcpy(tmp, &phdr, sizeof(phdr));
796 tmp += sizeof(phdr);
797
798 /* Remove unwanted PT_NOTE program headers. */
799 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
800 *elfsz = *elfsz - i;
801 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
802 memset(elfptr + *elfsz, 0, i);
803 *elfsz = roundup(*elfsz, PAGE_SIZE);
804
805 /* Modify e_phnum to reflect merged headers. */
806 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
807
808 return 0;
809}
810
811/* Add memory chunks represented by program headers to vmcore list. Also update
812 * the new offset fields of exported program headers. */
813static int __init process_ptload_program_headers_elf64(char *elfptr,
814 size_t elfsz,
815 size_t elfnotes_sz,
816 struct list_head *vc_list)
817{
818 int i;
819 Elf64_Ehdr *ehdr_ptr;
820 Elf64_Phdr *phdr_ptr;
821 loff_t vmcore_off;
822 struct vmcore *new;
823
824 ehdr_ptr = (Elf64_Ehdr *)elfptr;
825 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
826
827 /* Skip Elf header, program headers and Elf note segment. */
828 vmcore_off = elfsz + elfnotes_sz;
829
830 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
831 u64 paddr, start, end, size;
832
833 if (phdr_ptr->p_type != PT_LOAD)
834 continue;
835
836 paddr = phdr_ptr->p_offset;
837 start = rounddown(paddr, PAGE_SIZE);
838 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
839 size = end - start;
840
841 /* Add this contiguous chunk of memory to vmcore list.*/
842 new = get_new_element();
843 if (!new)
844 return -ENOMEM;
845 new->paddr = start;
846 new->size = size;
847 list_add_tail(&new->list, vc_list);
848
849 /* Update the program header offset. */
850 phdr_ptr->p_offset = vmcore_off + (paddr - start);
851 vmcore_off = vmcore_off + size;
852 }
853 return 0;
854}
855
856static int __init process_ptload_program_headers_elf32(char *elfptr,
857 size_t elfsz,
858 size_t elfnotes_sz,
859 struct list_head *vc_list)
860{
861 int i;
862 Elf32_Ehdr *ehdr_ptr;
863 Elf32_Phdr *phdr_ptr;
864 loff_t vmcore_off;
865 struct vmcore *new;
866
867 ehdr_ptr = (Elf32_Ehdr *)elfptr;
868 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
869
870 /* Skip Elf header, program headers and Elf note segment. */
871 vmcore_off = elfsz + elfnotes_sz;
872
873 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
874 u64 paddr, start, end, size;
875
876 if (phdr_ptr->p_type != PT_LOAD)
877 continue;
878
879 paddr = phdr_ptr->p_offset;
880 start = rounddown(paddr, PAGE_SIZE);
881 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
882 size = end - start;
883
884 /* Add this contiguous chunk of memory to vmcore list.*/
885 new = get_new_element();
886 if (!new)
887 return -ENOMEM;
888 new->paddr = start;
889 new->size = size;
890 list_add_tail(&new->list, vc_list);
891
892 /* Update the program header offset */
893 phdr_ptr->p_offset = vmcore_off + (paddr - start);
894 vmcore_off = vmcore_off + size;
895 }
896 return 0;
897}
898
899/* Sets offset fields of vmcore elements. */
900static void __init set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
901 struct list_head *vc_list)
902{
903 loff_t vmcore_off;
904 struct vmcore *m;
905
906 /* Skip Elf header, program headers and Elf note segment. */
907 vmcore_off = elfsz + elfnotes_sz;
908
909 list_for_each_entry(m, vc_list, list) {
910 m->offset = vmcore_off;
911 vmcore_off += m->size;
912 }
913}
914
915static void free_elfcorebuf(void)
916{
917 free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
918 elfcorebuf = NULL;
919 vfree(elfnotes_buf);
920 elfnotes_buf = NULL;
921}
922
923static int __init parse_crash_elf64_headers(void)
924{
925 int rc=0;
926 Elf64_Ehdr ehdr;
927 u64 addr;
928
929 addr = elfcorehdr_addr;
930
931 /* Read Elf header */
932 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
933 if (rc < 0)
934 return rc;
935
936 /* Do some basic Verification. */
937 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
938 (ehdr.e_type != ET_CORE) ||
939 !vmcore_elf64_check_arch(&ehdr) ||
940 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
941 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
942 ehdr.e_version != EV_CURRENT ||
943 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
944 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
945 ehdr.e_phnum == 0) {
946 pr_warn("Warning: Core image elf header is not sane\n");
947 return -EINVAL;
948 }
949
950 /* Read in all elf headers. */
951 elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
952 ehdr.e_phnum * sizeof(Elf64_Phdr);
953 elfcorebuf_sz = elfcorebuf_sz_orig;
954 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
955 get_order(elfcorebuf_sz_orig));
956 if (!elfcorebuf)
957 return -ENOMEM;
958 addr = elfcorehdr_addr;
959 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
960 if (rc < 0)
961 goto fail;
962
963 /* Merge all PT_NOTE headers into one. */
964 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
965 &elfnotes_buf, &elfnotes_sz);
966 if (rc)
967 goto fail;
968 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
969 elfnotes_sz, &vmcore_list);
970 if (rc)
971 goto fail;
972 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
973 return 0;
974fail:
975 free_elfcorebuf();
976 return rc;
977}
978
979static int __init parse_crash_elf32_headers(void)
980{
981 int rc=0;
982 Elf32_Ehdr ehdr;
983 u64 addr;
984
985 addr = elfcorehdr_addr;
986
987 /* Read Elf header */
988 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
989 if (rc < 0)
990 return rc;
991
992 /* Do some basic Verification. */
993 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
994 (ehdr.e_type != ET_CORE) ||
995 !elf_check_arch(&ehdr) ||
996 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
997 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
998 ehdr.e_version != EV_CURRENT ||
999 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1000 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1001 ehdr.e_phnum == 0) {
1002 pr_warn("Warning: Core image elf header is not sane\n");
1003 return -EINVAL;
1004 }
1005
1006 /* Read in all elf headers. */
1007 elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1008 elfcorebuf_sz = elfcorebuf_sz_orig;
1009 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1010 get_order(elfcorebuf_sz_orig));
1011 if (!elfcorebuf)
1012 return -ENOMEM;
1013 addr = elfcorehdr_addr;
1014 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1015 if (rc < 0)
1016 goto fail;
1017
1018 /* Merge all PT_NOTE headers into one. */
1019 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1020 &elfnotes_buf, &elfnotes_sz);
1021 if (rc)
1022 goto fail;
1023 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1024 elfnotes_sz, &vmcore_list);
1025 if (rc)
1026 goto fail;
1027 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1028 return 0;
1029fail:
1030 free_elfcorebuf();
1031 return rc;
1032}
1033
1034static int __init parse_crash_elf_headers(void)
1035{
1036 unsigned char e_ident[EI_NIDENT];
1037 u64 addr;
1038 int rc=0;
1039
1040 addr = elfcorehdr_addr;
1041 rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1042 if (rc < 0)
1043 return rc;
1044 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1045 pr_warn("Warning: Core image elf header not found\n");
1046 return -EINVAL;
1047 }
1048
1049 if (e_ident[EI_CLASS] == ELFCLASS64) {
1050 rc = parse_crash_elf64_headers();
1051 if (rc)
1052 return rc;
1053 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
1054 rc = parse_crash_elf32_headers();
1055 if (rc)
1056 return rc;
1057 } else {
1058 pr_warn("Warning: Core image elf header is not sane\n");
1059 return -EINVAL;
1060 }
1061
1062 /* Determine vmcore size. */
1063 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1064 &vmcore_list);
1065
1066 return 0;
1067}
1068
1069/* Init function for vmcore module. */
1070static int __init vmcore_init(void)
1071{
1072 int rc = 0;
1073
1074 /* Allow architectures to allocate ELF header in 2nd kernel */
1075 rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1076 if (rc)
1077 return rc;
1078 /*
1079 * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1080 * then capture the dump.
1081 */
1082 if (!(is_vmcore_usable()))
1083 return rc;
1084 rc = parse_crash_elf_headers();
1085 if (rc) {
1086 pr_warn("Kdump: vmcore not initialized\n");
1087 return rc;
1088 }
1089 elfcorehdr_free(elfcorehdr_addr);
1090 elfcorehdr_addr = ELFCORE_ADDR_ERR;
1091
1092 proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
1093 if (proc_vmcore)
1094 proc_vmcore->size = vmcore_size;
1095 return 0;
1096}
1097fs_initcall(vmcore_init);
1098
1099/* Cleanup function for vmcore module. */
1100void vmcore_cleanup(void)
1101{
1102 struct list_head *pos, *next;
1103
1104 if (proc_vmcore) {
1105 proc_remove(proc_vmcore);
1106 proc_vmcore = NULL;
1107 }
1108
1109 /* clear the vmcore list. */
1110 list_for_each_safe(pos, next, &vmcore_list) {
1111 struct vmcore *m;
1112
1113 m = list_entry(pos, struct vmcore, list);
1114 list_del(&m->list);
1115 kfree(m);
1116 }
1117 free_elfcorebuf();
1118}