xref: /linux/fs/proc/vmcore.c (revision a5766f11cfd3a0c03450d99c8fe548c2940be884)
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/highmem.h>
16 #include <linux/bootmem.h>
17 #include <linux/init.h>
18 #include <linux/crash_dump.h>
19 #include <linux/list.h>
20 #include <asm/uaccess.h>
21 #include <asm/io.h>
22 
23 /* List representing chunks of contiguous memory areas and their offsets in
24  * vmcore file.
25  */
26 static LIST_HEAD(vmcore_list);
27 
28 /* Stores the pointer to the buffer containing kernel elf core headers. */
29 static char *elfcorebuf;
30 static size_t elfcorebuf_sz;
31 
32 /* Total size of vmcore file. */
33 static u64 vmcore_size;
34 
35 /* Stores the physical address of elf header of crash image. */
36 unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
37 
38 struct proc_dir_entry *proc_vmcore = NULL;
39 
40 /* Reads a page from the oldmem device from given offset. */
41 static ssize_t read_from_oldmem(char *buf, size_t count,
42 				u64 *ppos, int userbuf)
43 {
44 	unsigned long pfn, offset;
45 	size_t nr_bytes;
46 	ssize_t read = 0, tmp;
47 
48 	if (!count)
49 		return 0;
50 
51 	offset = (unsigned long)(*ppos % PAGE_SIZE);
52 	pfn = (unsigned long)(*ppos / PAGE_SIZE);
53 	if (pfn > saved_max_pfn)
54 		return -EINVAL;
55 
56 	do {
57 		if (count > (PAGE_SIZE - offset))
58 			nr_bytes = PAGE_SIZE - offset;
59 		else
60 			nr_bytes = count;
61 
62 		tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf);
63 		if (tmp < 0)
64 			return tmp;
65 		*ppos += nr_bytes;
66 		count -= nr_bytes;
67 		buf += nr_bytes;
68 		read += nr_bytes;
69 		++pfn;
70 		offset = 0;
71 	} while (count);
72 
73 	return read;
74 }
75 
76 /* Maps vmcore file offset to respective physical address in memroy. */
77 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
78 					struct vmcore **m_ptr)
79 {
80 	struct vmcore *m;
81 	u64 paddr;
82 
83 	list_for_each_entry(m, vc_list, list) {
84 		u64 start, end;
85 		start = m->offset;
86 		end = m->offset + m->size - 1;
87 		if (offset >= start && offset <= end) {
88 			paddr = m->paddr + offset - start;
89 			*m_ptr = m;
90 			return paddr;
91 		}
92 	}
93 	*m_ptr = NULL;
94 	return 0;
95 }
96 
97 /* Read from the ELF header and then the crash dump. On error, negative value is
98  * returned otherwise number of bytes read are returned.
99  */
100 static ssize_t read_vmcore(struct file *file, char __user *buffer,
101 				size_t buflen, loff_t *fpos)
102 {
103 	ssize_t acc = 0, tmp;
104 	size_t tsz;
105 	u64 start, nr_bytes;
106 	struct vmcore *curr_m = NULL;
107 
108 	if (buflen == 0 || *fpos >= vmcore_size)
109 		return 0;
110 
111 	/* trim buflen to not go beyond EOF */
112 	if (buflen > vmcore_size - *fpos)
113 		buflen = vmcore_size - *fpos;
114 
115 	/* Read ELF core header */
116 	if (*fpos < elfcorebuf_sz) {
117 		tsz = elfcorebuf_sz - *fpos;
118 		if (buflen < tsz)
119 			tsz = buflen;
120 		if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
121 			return -EFAULT;
122 		buflen -= tsz;
123 		*fpos += tsz;
124 		buffer += tsz;
125 		acc += tsz;
126 
127 		/* leave now if filled buffer already */
128 		if (buflen == 0)
129 			return acc;
130 	}
131 
132 	start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
133 	if (!curr_m)
134         	return -EINVAL;
135 	if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
136 		tsz = buflen;
137 
138 	/* Calculate left bytes in current memory segment. */
139 	nr_bytes = (curr_m->size - (start - curr_m->paddr));
140 	if (tsz > nr_bytes)
141 		tsz = nr_bytes;
142 
143 	while (buflen) {
144 		tmp = read_from_oldmem(buffer, tsz, &start, 1);
145 		if (tmp < 0)
146 			return tmp;
147 		buflen -= tsz;
148 		*fpos += tsz;
149 		buffer += tsz;
150 		acc += tsz;
151 		if (start >= (curr_m->paddr + curr_m->size)) {
152 			if (curr_m->list.next == &vmcore_list)
153 				return acc;	/*EOF*/
154 			curr_m = list_entry(curr_m->list.next,
155 						struct vmcore, list);
156 			start = curr_m->paddr;
157 		}
158 		if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
159 			tsz = buflen;
160 		/* Calculate left bytes in current memory segment. */
161 		nr_bytes = (curr_m->size - (start - curr_m->paddr));
162 		if (tsz > nr_bytes)
163 			tsz = nr_bytes;
164 	}
165 	return acc;
166 }
167 
168 const struct file_operations proc_vmcore_operations = {
169 	.read		= read_vmcore,
170 };
171 
172 static struct vmcore* __init get_new_element(void)
173 {
174 	struct vmcore *p;
175 
176 	p = kmalloc(sizeof(*p), GFP_KERNEL);
177 	if (p)
178 		memset(p, 0, sizeof(*p));
179 	return p;
180 }
181 
182 static u64 __init get_vmcore_size_elf64(char *elfptr)
183 {
184 	int i;
185 	u64 size;
186 	Elf64_Ehdr *ehdr_ptr;
187 	Elf64_Phdr *phdr_ptr;
188 
189 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
190 	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
191 	size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
192 	for (i = 0; i < ehdr_ptr->e_phnum; i++) {
193 		size += phdr_ptr->p_memsz;
194 		phdr_ptr++;
195 	}
196 	return size;
197 }
198 
199 static u64 __init get_vmcore_size_elf32(char *elfptr)
200 {
201 	int i;
202 	u64 size;
203 	Elf32_Ehdr *ehdr_ptr;
204 	Elf32_Phdr *phdr_ptr;
205 
206 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
207 	phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
208 	size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
209 	for (i = 0; i < ehdr_ptr->e_phnum; i++) {
210 		size += phdr_ptr->p_memsz;
211 		phdr_ptr++;
212 	}
213 	return size;
214 }
215 
216 /* Merges all the PT_NOTE headers into one. */
217 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
218 						struct list_head *vc_list)
219 {
220 	int i, nr_ptnote=0, rc=0;
221 	char *tmp;
222 	Elf64_Ehdr *ehdr_ptr;
223 	Elf64_Phdr phdr, *phdr_ptr;
224 	Elf64_Nhdr *nhdr_ptr;
225 	u64 phdr_sz = 0, note_off;
226 
227 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
228 	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
229 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
230 		int j;
231 		void *notes_section;
232 		struct vmcore *new;
233 		u64 offset, max_sz, sz, real_sz = 0;
234 		if (phdr_ptr->p_type != PT_NOTE)
235 			continue;
236 		nr_ptnote++;
237 		max_sz = phdr_ptr->p_memsz;
238 		offset = phdr_ptr->p_offset;
239 		notes_section = kmalloc(max_sz, GFP_KERNEL);
240 		if (!notes_section)
241 			return -ENOMEM;
242 		rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
243 		if (rc < 0) {
244 			kfree(notes_section);
245 			return rc;
246 		}
247 		nhdr_ptr = notes_section;
248 		for (j = 0; j < max_sz; j += sz) {
249 			if (nhdr_ptr->n_namesz == 0)
250 				break;
251 			sz = sizeof(Elf64_Nhdr) +
252 				((nhdr_ptr->n_namesz + 3) & ~3) +
253 				((nhdr_ptr->n_descsz + 3) & ~3);
254 			real_sz += sz;
255 			nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
256 		}
257 
258 		/* Add this contiguous chunk of notes section to vmcore list.*/
259 		new = get_new_element();
260 		if (!new) {
261 			kfree(notes_section);
262 			return -ENOMEM;
263 		}
264 		new->paddr = phdr_ptr->p_offset;
265 		new->size = real_sz;
266 		list_add_tail(&new->list, vc_list);
267 		phdr_sz += real_sz;
268 		kfree(notes_section);
269 	}
270 
271 	/* Prepare merged PT_NOTE program header. */
272 	phdr.p_type    = PT_NOTE;
273 	phdr.p_flags   = 0;
274 	note_off = sizeof(Elf64_Ehdr) +
275 			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
276 	phdr.p_offset  = note_off;
277 	phdr.p_vaddr   = phdr.p_paddr = 0;
278 	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
279 	phdr.p_align   = 0;
280 
281 	/* Add merged PT_NOTE program header*/
282 	tmp = elfptr + sizeof(Elf64_Ehdr);
283 	memcpy(tmp, &phdr, sizeof(phdr));
284 	tmp += sizeof(phdr);
285 
286 	/* Remove unwanted PT_NOTE program headers. */
287 	i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
288 	*elfsz = *elfsz - i;
289 	memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
290 
291 	/* Modify e_phnum to reflect merged headers. */
292 	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
293 
294 	return 0;
295 }
296 
297 /* Merges all the PT_NOTE headers into one. */
298 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
299 						struct list_head *vc_list)
300 {
301 	int i, nr_ptnote=0, rc=0;
302 	char *tmp;
303 	Elf32_Ehdr *ehdr_ptr;
304 	Elf32_Phdr phdr, *phdr_ptr;
305 	Elf32_Nhdr *nhdr_ptr;
306 	u64 phdr_sz = 0, note_off;
307 
308 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
309 	phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
310 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
311 		int j;
312 		void *notes_section;
313 		struct vmcore *new;
314 		u64 offset, max_sz, sz, real_sz = 0;
315 		if (phdr_ptr->p_type != PT_NOTE)
316 			continue;
317 		nr_ptnote++;
318 		max_sz = phdr_ptr->p_memsz;
319 		offset = phdr_ptr->p_offset;
320 		notes_section = kmalloc(max_sz, GFP_KERNEL);
321 		if (!notes_section)
322 			return -ENOMEM;
323 		rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
324 		if (rc < 0) {
325 			kfree(notes_section);
326 			return rc;
327 		}
328 		nhdr_ptr = notes_section;
329 		for (j = 0; j < max_sz; j += sz) {
330 			if (nhdr_ptr->n_namesz == 0)
331 				break;
332 			sz = sizeof(Elf32_Nhdr) +
333 				((nhdr_ptr->n_namesz + 3) & ~3) +
334 				((nhdr_ptr->n_descsz + 3) & ~3);
335 			real_sz += sz;
336 			nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
337 		}
338 
339 		/* Add this contiguous chunk of notes section to vmcore list.*/
340 		new = get_new_element();
341 		if (!new) {
342 			kfree(notes_section);
343 			return -ENOMEM;
344 		}
345 		new->paddr = phdr_ptr->p_offset;
346 		new->size = real_sz;
347 		list_add_tail(&new->list, vc_list);
348 		phdr_sz += real_sz;
349 		kfree(notes_section);
350 	}
351 
352 	/* Prepare merged PT_NOTE program header. */
353 	phdr.p_type    = PT_NOTE;
354 	phdr.p_flags   = 0;
355 	note_off = sizeof(Elf32_Ehdr) +
356 			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
357 	phdr.p_offset  = note_off;
358 	phdr.p_vaddr   = phdr.p_paddr = 0;
359 	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
360 	phdr.p_align   = 0;
361 
362 	/* Add merged PT_NOTE program header*/
363 	tmp = elfptr + sizeof(Elf32_Ehdr);
364 	memcpy(tmp, &phdr, sizeof(phdr));
365 	tmp += sizeof(phdr);
366 
367 	/* Remove unwanted PT_NOTE program headers. */
368 	i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
369 	*elfsz = *elfsz - i;
370 	memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
371 
372 	/* Modify e_phnum to reflect merged headers. */
373 	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
374 
375 	return 0;
376 }
377 
378 /* Add memory chunks represented by program headers to vmcore list. Also update
379  * the new offset fields of exported program headers. */
380 static int __init process_ptload_program_headers_elf64(char *elfptr,
381 						size_t elfsz,
382 						struct list_head *vc_list)
383 {
384 	int i;
385 	Elf64_Ehdr *ehdr_ptr;
386 	Elf64_Phdr *phdr_ptr;
387 	loff_t vmcore_off;
388 	struct vmcore *new;
389 
390 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
391 	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
392 
393 	/* First program header is PT_NOTE header. */
394 	vmcore_off = sizeof(Elf64_Ehdr) +
395 			(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
396 			phdr_ptr->p_memsz; /* Note sections */
397 
398 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
399 		if (phdr_ptr->p_type != PT_LOAD)
400 			continue;
401 
402 		/* Add this contiguous chunk of memory to vmcore list.*/
403 		new = get_new_element();
404 		if (!new)
405 			return -ENOMEM;
406 		new->paddr = phdr_ptr->p_offset;
407 		new->size = phdr_ptr->p_memsz;
408 		list_add_tail(&new->list, vc_list);
409 
410 		/* Update the program header offset. */
411 		phdr_ptr->p_offset = vmcore_off;
412 		vmcore_off = vmcore_off + phdr_ptr->p_memsz;
413 	}
414 	return 0;
415 }
416 
417 static int __init process_ptload_program_headers_elf32(char *elfptr,
418 						size_t elfsz,
419 						struct list_head *vc_list)
420 {
421 	int i;
422 	Elf32_Ehdr *ehdr_ptr;
423 	Elf32_Phdr *phdr_ptr;
424 	loff_t vmcore_off;
425 	struct vmcore *new;
426 
427 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
428 	phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
429 
430 	/* First program header is PT_NOTE header. */
431 	vmcore_off = sizeof(Elf32_Ehdr) +
432 			(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
433 			phdr_ptr->p_memsz; /* Note sections */
434 
435 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
436 		if (phdr_ptr->p_type != PT_LOAD)
437 			continue;
438 
439 		/* Add this contiguous chunk of memory to vmcore list.*/
440 		new = get_new_element();
441 		if (!new)
442 			return -ENOMEM;
443 		new->paddr = phdr_ptr->p_offset;
444 		new->size = phdr_ptr->p_memsz;
445 		list_add_tail(&new->list, vc_list);
446 
447 		/* Update the program header offset */
448 		phdr_ptr->p_offset = vmcore_off;
449 		vmcore_off = vmcore_off + phdr_ptr->p_memsz;
450 	}
451 	return 0;
452 }
453 
454 /* Sets offset fields of vmcore elements. */
455 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
456 						struct list_head *vc_list)
457 {
458 	loff_t vmcore_off;
459 	Elf64_Ehdr *ehdr_ptr;
460 	struct vmcore *m;
461 
462 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
463 
464 	/* Skip Elf header and program headers. */
465 	vmcore_off = sizeof(Elf64_Ehdr) +
466 			(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
467 
468 	list_for_each_entry(m, vc_list, list) {
469 		m->offset = vmcore_off;
470 		vmcore_off += m->size;
471 	}
472 }
473 
474 /* Sets offset fields of vmcore elements. */
475 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
476 						struct list_head *vc_list)
477 {
478 	loff_t vmcore_off;
479 	Elf32_Ehdr *ehdr_ptr;
480 	struct vmcore *m;
481 
482 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
483 
484 	/* Skip Elf header and program headers. */
485 	vmcore_off = sizeof(Elf32_Ehdr) +
486 			(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
487 
488 	list_for_each_entry(m, vc_list, list) {
489 		m->offset = vmcore_off;
490 		vmcore_off += m->size;
491 	}
492 }
493 
494 static int __init parse_crash_elf64_headers(void)
495 {
496 	int rc=0;
497 	Elf64_Ehdr ehdr;
498 	u64 addr;
499 
500 	addr = elfcorehdr_addr;
501 
502 	/* Read Elf header */
503 	rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
504 	if (rc < 0)
505 		return rc;
506 
507 	/* Do some basic Verification. */
508 	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
509 		(ehdr.e_type != ET_CORE) ||
510 		!vmcore_elf_check_arch(&ehdr) ||
511 		ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
512 		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
513 		ehdr.e_version != EV_CURRENT ||
514 		ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
515 		ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
516 		ehdr.e_phnum == 0) {
517 		printk(KERN_WARNING "Warning: Core image elf header is not"
518 					"sane\n");
519 		return -EINVAL;
520 	}
521 
522 	/* Read in all elf headers. */
523 	elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
524 	elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
525 	if (!elfcorebuf)
526 		return -ENOMEM;
527 	addr = elfcorehdr_addr;
528 	rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
529 	if (rc < 0) {
530 		kfree(elfcorebuf);
531 		return rc;
532 	}
533 
534 	/* Merge all PT_NOTE headers into one. */
535 	rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
536 	if (rc) {
537 		kfree(elfcorebuf);
538 		return rc;
539 	}
540 	rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
541 							&vmcore_list);
542 	if (rc) {
543 		kfree(elfcorebuf);
544 		return rc;
545 	}
546 	set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
547 	return 0;
548 }
549 
550 static int __init parse_crash_elf32_headers(void)
551 {
552 	int rc=0;
553 	Elf32_Ehdr ehdr;
554 	u64 addr;
555 
556 	addr = elfcorehdr_addr;
557 
558 	/* Read Elf header */
559 	rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
560 	if (rc < 0)
561 		return rc;
562 
563 	/* Do some basic Verification. */
564 	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
565 		(ehdr.e_type != ET_CORE) ||
566 		!elf_check_arch(&ehdr) ||
567 		ehdr.e_ident[EI_CLASS] != ELFCLASS32||
568 		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
569 		ehdr.e_version != EV_CURRENT ||
570 		ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
571 		ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
572 		ehdr.e_phnum == 0) {
573 		printk(KERN_WARNING "Warning: Core image elf header is not"
574 					"sane\n");
575 		return -EINVAL;
576 	}
577 
578 	/* Read in all elf headers. */
579 	elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
580 	elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
581 	if (!elfcorebuf)
582 		return -ENOMEM;
583 	addr = elfcorehdr_addr;
584 	rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
585 	if (rc < 0) {
586 		kfree(elfcorebuf);
587 		return rc;
588 	}
589 
590 	/* Merge all PT_NOTE headers into one. */
591 	rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
592 	if (rc) {
593 		kfree(elfcorebuf);
594 		return rc;
595 	}
596 	rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
597 								&vmcore_list);
598 	if (rc) {
599 		kfree(elfcorebuf);
600 		return rc;
601 	}
602 	set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
603 	return 0;
604 }
605 
606 static int __init parse_crash_elf_headers(void)
607 {
608 	unsigned char e_ident[EI_NIDENT];
609 	u64 addr;
610 	int rc=0;
611 
612 	addr = elfcorehdr_addr;
613 	rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
614 	if (rc < 0)
615 		return rc;
616 	if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
617 		printk(KERN_WARNING "Warning: Core image elf header"
618 					" not found\n");
619 		return -EINVAL;
620 	}
621 
622 	if (e_ident[EI_CLASS] == ELFCLASS64) {
623 		rc = parse_crash_elf64_headers();
624 		if (rc)
625 			return rc;
626 
627 		/* Determine vmcore size. */
628 		vmcore_size = get_vmcore_size_elf64(elfcorebuf);
629 	} else if (e_ident[EI_CLASS] == ELFCLASS32) {
630 		rc = parse_crash_elf32_headers();
631 		if (rc)
632 			return rc;
633 
634 		/* Determine vmcore size. */
635 		vmcore_size = get_vmcore_size_elf32(elfcorebuf);
636 	} else {
637 		printk(KERN_WARNING "Warning: Core image elf header is not"
638 					" sane\n");
639 		return -EINVAL;
640 	}
641 	return 0;
642 }
643 
644 /* Init function for vmcore module. */
645 static int __init vmcore_init(void)
646 {
647 	int rc = 0;
648 
649 	/* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
650 	if (!(elfcorehdr_addr < ELFCORE_ADDR_MAX))
651 		return rc;
652 	rc = parse_crash_elf_headers();
653 	if (rc) {
654 		printk(KERN_WARNING "Kdump: vmcore not initialized\n");
655 		return rc;
656 	}
657 
658 	/* Initialize /proc/vmcore size if proc is already up. */
659 	if (proc_vmcore)
660 		proc_vmcore->size = vmcore_size;
661 	return 0;
662 }
663 module_init(vmcore_init)
664