xref: /openbmc/linux/fs/proc/vmcore.c (revision 367b8112)
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 static struct proc_dir_entry *proc_vmcore = NULL;
36 
37 /* Reads a page from the oldmem device from given offset. */
38 static ssize_t read_from_oldmem(char *buf, size_t count,
39 				u64 *ppos, int userbuf)
40 {
41 	unsigned long pfn, offset;
42 	size_t nr_bytes;
43 	ssize_t read = 0, tmp;
44 
45 	if (!count)
46 		return 0;
47 
48 	offset = (unsigned long)(*ppos % PAGE_SIZE);
49 	pfn = (unsigned long)(*ppos / PAGE_SIZE);
50 	if (pfn > saved_max_pfn)
51 		return -EINVAL;
52 
53 	do {
54 		if (count > (PAGE_SIZE - offset))
55 			nr_bytes = PAGE_SIZE - offset;
56 		else
57 			nr_bytes = count;
58 
59 		tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf);
60 		if (tmp < 0)
61 			return tmp;
62 		*ppos += nr_bytes;
63 		count -= nr_bytes;
64 		buf += nr_bytes;
65 		read += nr_bytes;
66 		++pfn;
67 		offset = 0;
68 	} while (count);
69 
70 	return read;
71 }
72 
73 /* Maps vmcore file offset to respective physical address in memroy. */
74 static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
75 					struct vmcore **m_ptr)
76 {
77 	struct vmcore *m;
78 	u64 paddr;
79 
80 	list_for_each_entry(m, vc_list, list) {
81 		u64 start, end;
82 		start = m->offset;
83 		end = m->offset + m->size - 1;
84 		if (offset >= start && offset <= end) {
85 			paddr = m->paddr + offset - start;
86 			*m_ptr = m;
87 			return paddr;
88 		}
89 	}
90 	*m_ptr = NULL;
91 	return 0;
92 }
93 
94 /* Read from the ELF header and then the crash dump. On error, negative value is
95  * returned otherwise number of bytes read are returned.
96  */
97 static ssize_t read_vmcore(struct file *file, char __user *buffer,
98 				size_t buflen, loff_t *fpos)
99 {
100 	ssize_t acc = 0, tmp;
101 	size_t tsz;
102 	u64 start, nr_bytes;
103 	struct vmcore *curr_m = NULL;
104 
105 	if (buflen == 0 || *fpos >= vmcore_size)
106 		return 0;
107 
108 	/* trim buflen to not go beyond EOF */
109 	if (buflen > vmcore_size - *fpos)
110 		buflen = vmcore_size - *fpos;
111 
112 	/* Read ELF core header */
113 	if (*fpos < elfcorebuf_sz) {
114 		tsz = elfcorebuf_sz - *fpos;
115 		if (buflen < tsz)
116 			tsz = buflen;
117 		if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
118 			return -EFAULT;
119 		buflen -= tsz;
120 		*fpos += tsz;
121 		buffer += tsz;
122 		acc += tsz;
123 
124 		/* leave now if filled buffer already */
125 		if (buflen == 0)
126 			return acc;
127 	}
128 
129 	start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
130 	if (!curr_m)
131         	return -EINVAL;
132 	if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
133 		tsz = buflen;
134 
135 	/* Calculate left bytes in current memory segment. */
136 	nr_bytes = (curr_m->size - (start - curr_m->paddr));
137 	if (tsz > nr_bytes)
138 		tsz = nr_bytes;
139 
140 	while (buflen) {
141 		tmp = read_from_oldmem(buffer, tsz, &start, 1);
142 		if (tmp < 0)
143 			return tmp;
144 		buflen -= tsz;
145 		*fpos += tsz;
146 		buffer += tsz;
147 		acc += tsz;
148 		if (start >= (curr_m->paddr + curr_m->size)) {
149 			if (curr_m->list.next == &vmcore_list)
150 				return acc;	/*EOF*/
151 			curr_m = list_entry(curr_m->list.next,
152 						struct vmcore, list);
153 			start = curr_m->paddr;
154 		}
155 		if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
156 			tsz = buflen;
157 		/* Calculate left bytes in current memory segment. */
158 		nr_bytes = (curr_m->size - (start - curr_m->paddr));
159 		if (tsz > nr_bytes)
160 			tsz = nr_bytes;
161 	}
162 	return acc;
163 }
164 
165 static const struct file_operations proc_vmcore_operations = {
166 	.read		= read_vmcore,
167 };
168 
169 static struct vmcore* __init get_new_element(void)
170 {
171 	struct vmcore *p;
172 
173 	p = kmalloc(sizeof(*p), GFP_KERNEL);
174 	if (p)
175 		memset(p, 0, sizeof(*p));
176 	return p;
177 }
178 
179 static u64 __init get_vmcore_size_elf64(char *elfptr)
180 {
181 	int i;
182 	u64 size;
183 	Elf64_Ehdr *ehdr_ptr;
184 	Elf64_Phdr *phdr_ptr;
185 
186 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
187 	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
188 	size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
189 	for (i = 0; i < ehdr_ptr->e_phnum; i++) {
190 		size += phdr_ptr->p_memsz;
191 		phdr_ptr++;
192 	}
193 	return size;
194 }
195 
196 static u64 __init get_vmcore_size_elf32(char *elfptr)
197 {
198 	int i;
199 	u64 size;
200 	Elf32_Ehdr *ehdr_ptr;
201 	Elf32_Phdr *phdr_ptr;
202 
203 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
204 	phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
205 	size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
206 	for (i = 0; i < ehdr_ptr->e_phnum; i++) {
207 		size += phdr_ptr->p_memsz;
208 		phdr_ptr++;
209 	}
210 	return size;
211 }
212 
213 /* Merges all the PT_NOTE headers into one. */
214 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
215 						struct list_head *vc_list)
216 {
217 	int i, nr_ptnote=0, rc=0;
218 	char *tmp;
219 	Elf64_Ehdr *ehdr_ptr;
220 	Elf64_Phdr phdr, *phdr_ptr;
221 	Elf64_Nhdr *nhdr_ptr;
222 	u64 phdr_sz = 0, note_off;
223 
224 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
225 	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
226 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
227 		int j;
228 		void *notes_section;
229 		struct vmcore *new;
230 		u64 offset, max_sz, sz, real_sz = 0;
231 		if (phdr_ptr->p_type != PT_NOTE)
232 			continue;
233 		nr_ptnote++;
234 		max_sz = phdr_ptr->p_memsz;
235 		offset = phdr_ptr->p_offset;
236 		notes_section = kmalloc(max_sz, GFP_KERNEL);
237 		if (!notes_section)
238 			return -ENOMEM;
239 		rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
240 		if (rc < 0) {
241 			kfree(notes_section);
242 			return rc;
243 		}
244 		nhdr_ptr = notes_section;
245 		for (j = 0; j < max_sz; j += sz) {
246 			if (nhdr_ptr->n_namesz == 0)
247 				break;
248 			sz = sizeof(Elf64_Nhdr) +
249 				((nhdr_ptr->n_namesz + 3) & ~3) +
250 				((nhdr_ptr->n_descsz + 3) & ~3);
251 			real_sz += sz;
252 			nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
253 		}
254 
255 		/* Add this contiguous chunk of notes section to vmcore list.*/
256 		new = get_new_element();
257 		if (!new) {
258 			kfree(notes_section);
259 			return -ENOMEM;
260 		}
261 		new->paddr = phdr_ptr->p_offset;
262 		new->size = real_sz;
263 		list_add_tail(&new->list, vc_list);
264 		phdr_sz += real_sz;
265 		kfree(notes_section);
266 	}
267 
268 	/* Prepare merged PT_NOTE program header. */
269 	phdr.p_type    = PT_NOTE;
270 	phdr.p_flags   = 0;
271 	note_off = sizeof(Elf64_Ehdr) +
272 			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
273 	phdr.p_offset  = note_off;
274 	phdr.p_vaddr   = phdr.p_paddr = 0;
275 	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
276 	phdr.p_align   = 0;
277 
278 	/* Add merged PT_NOTE program header*/
279 	tmp = elfptr + sizeof(Elf64_Ehdr);
280 	memcpy(tmp, &phdr, sizeof(phdr));
281 	tmp += sizeof(phdr);
282 
283 	/* Remove unwanted PT_NOTE program headers. */
284 	i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
285 	*elfsz = *elfsz - i;
286 	memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
287 
288 	/* Modify e_phnum to reflect merged headers. */
289 	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
290 
291 	return 0;
292 }
293 
294 /* Merges all the PT_NOTE headers into one. */
295 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
296 						struct list_head *vc_list)
297 {
298 	int i, nr_ptnote=0, rc=0;
299 	char *tmp;
300 	Elf32_Ehdr *ehdr_ptr;
301 	Elf32_Phdr phdr, *phdr_ptr;
302 	Elf32_Nhdr *nhdr_ptr;
303 	u64 phdr_sz = 0, note_off;
304 
305 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
306 	phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
307 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
308 		int j;
309 		void *notes_section;
310 		struct vmcore *new;
311 		u64 offset, max_sz, sz, real_sz = 0;
312 		if (phdr_ptr->p_type != PT_NOTE)
313 			continue;
314 		nr_ptnote++;
315 		max_sz = phdr_ptr->p_memsz;
316 		offset = phdr_ptr->p_offset;
317 		notes_section = kmalloc(max_sz, GFP_KERNEL);
318 		if (!notes_section)
319 			return -ENOMEM;
320 		rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
321 		if (rc < 0) {
322 			kfree(notes_section);
323 			return rc;
324 		}
325 		nhdr_ptr = notes_section;
326 		for (j = 0; j < max_sz; j += sz) {
327 			if (nhdr_ptr->n_namesz == 0)
328 				break;
329 			sz = sizeof(Elf32_Nhdr) +
330 				((nhdr_ptr->n_namesz + 3) & ~3) +
331 				((nhdr_ptr->n_descsz + 3) & ~3);
332 			real_sz += sz;
333 			nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
334 		}
335 
336 		/* Add this contiguous chunk of notes section to vmcore list.*/
337 		new = get_new_element();
338 		if (!new) {
339 			kfree(notes_section);
340 			return -ENOMEM;
341 		}
342 		new->paddr = phdr_ptr->p_offset;
343 		new->size = real_sz;
344 		list_add_tail(&new->list, vc_list);
345 		phdr_sz += real_sz;
346 		kfree(notes_section);
347 	}
348 
349 	/* Prepare merged PT_NOTE program header. */
350 	phdr.p_type    = PT_NOTE;
351 	phdr.p_flags   = 0;
352 	note_off = sizeof(Elf32_Ehdr) +
353 			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
354 	phdr.p_offset  = note_off;
355 	phdr.p_vaddr   = phdr.p_paddr = 0;
356 	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
357 	phdr.p_align   = 0;
358 
359 	/* Add merged PT_NOTE program header*/
360 	tmp = elfptr + sizeof(Elf32_Ehdr);
361 	memcpy(tmp, &phdr, sizeof(phdr));
362 	tmp += sizeof(phdr);
363 
364 	/* Remove unwanted PT_NOTE program headers. */
365 	i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
366 	*elfsz = *elfsz - i;
367 	memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
368 
369 	/* Modify e_phnum to reflect merged headers. */
370 	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
371 
372 	return 0;
373 }
374 
375 /* Add memory chunks represented by program headers to vmcore list. Also update
376  * the new offset fields of exported program headers. */
377 static int __init process_ptload_program_headers_elf64(char *elfptr,
378 						size_t elfsz,
379 						struct list_head *vc_list)
380 {
381 	int i;
382 	Elf64_Ehdr *ehdr_ptr;
383 	Elf64_Phdr *phdr_ptr;
384 	loff_t vmcore_off;
385 	struct vmcore *new;
386 
387 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
388 	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
389 
390 	/* First program header is PT_NOTE header. */
391 	vmcore_off = sizeof(Elf64_Ehdr) +
392 			(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
393 			phdr_ptr->p_memsz; /* Note sections */
394 
395 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
396 		if (phdr_ptr->p_type != PT_LOAD)
397 			continue;
398 
399 		/* Add this contiguous chunk of memory to vmcore list.*/
400 		new = get_new_element();
401 		if (!new)
402 			return -ENOMEM;
403 		new->paddr = phdr_ptr->p_offset;
404 		new->size = phdr_ptr->p_memsz;
405 		list_add_tail(&new->list, vc_list);
406 
407 		/* Update the program header offset. */
408 		phdr_ptr->p_offset = vmcore_off;
409 		vmcore_off = vmcore_off + phdr_ptr->p_memsz;
410 	}
411 	return 0;
412 }
413 
414 static int __init process_ptload_program_headers_elf32(char *elfptr,
415 						size_t elfsz,
416 						struct list_head *vc_list)
417 {
418 	int i;
419 	Elf32_Ehdr *ehdr_ptr;
420 	Elf32_Phdr *phdr_ptr;
421 	loff_t vmcore_off;
422 	struct vmcore *new;
423 
424 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
425 	phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
426 
427 	/* First program header is PT_NOTE header. */
428 	vmcore_off = sizeof(Elf32_Ehdr) +
429 			(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
430 			phdr_ptr->p_memsz; /* Note sections */
431 
432 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
433 		if (phdr_ptr->p_type != PT_LOAD)
434 			continue;
435 
436 		/* Add this contiguous chunk of memory to vmcore list.*/
437 		new = get_new_element();
438 		if (!new)
439 			return -ENOMEM;
440 		new->paddr = phdr_ptr->p_offset;
441 		new->size = phdr_ptr->p_memsz;
442 		list_add_tail(&new->list, vc_list);
443 
444 		/* Update the program header offset */
445 		phdr_ptr->p_offset = vmcore_off;
446 		vmcore_off = vmcore_off + phdr_ptr->p_memsz;
447 	}
448 	return 0;
449 }
450 
451 /* Sets offset fields of vmcore elements. */
452 static void __init set_vmcore_list_offsets_elf64(char *elfptr,
453 						struct list_head *vc_list)
454 {
455 	loff_t vmcore_off;
456 	Elf64_Ehdr *ehdr_ptr;
457 	struct vmcore *m;
458 
459 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
460 
461 	/* Skip Elf header and program headers. */
462 	vmcore_off = sizeof(Elf64_Ehdr) +
463 			(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
464 
465 	list_for_each_entry(m, vc_list, list) {
466 		m->offset = vmcore_off;
467 		vmcore_off += m->size;
468 	}
469 }
470 
471 /* Sets offset fields of vmcore elements. */
472 static void __init set_vmcore_list_offsets_elf32(char *elfptr,
473 						struct list_head *vc_list)
474 {
475 	loff_t vmcore_off;
476 	Elf32_Ehdr *ehdr_ptr;
477 	struct vmcore *m;
478 
479 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
480 
481 	/* Skip Elf header and program headers. */
482 	vmcore_off = sizeof(Elf32_Ehdr) +
483 			(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
484 
485 	list_for_each_entry(m, vc_list, list) {
486 		m->offset = vmcore_off;
487 		vmcore_off += m->size;
488 	}
489 }
490 
491 static int __init parse_crash_elf64_headers(void)
492 {
493 	int rc=0;
494 	Elf64_Ehdr ehdr;
495 	u64 addr;
496 
497 	addr = elfcorehdr_addr;
498 
499 	/* Read Elf header */
500 	rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
501 	if (rc < 0)
502 		return rc;
503 
504 	/* Do some basic Verification. */
505 	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
506 		(ehdr.e_type != ET_CORE) ||
507 		!vmcore_elf_check_arch(&ehdr) ||
508 		ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
509 		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
510 		ehdr.e_version != EV_CURRENT ||
511 		ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
512 		ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
513 		ehdr.e_phnum == 0) {
514 		printk(KERN_WARNING "Warning: Core image elf header is not"
515 					"sane\n");
516 		return -EINVAL;
517 	}
518 
519 	/* Read in all elf headers. */
520 	elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
521 	elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
522 	if (!elfcorebuf)
523 		return -ENOMEM;
524 	addr = elfcorehdr_addr;
525 	rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
526 	if (rc < 0) {
527 		kfree(elfcorebuf);
528 		return rc;
529 	}
530 
531 	/* Merge all PT_NOTE headers into one. */
532 	rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
533 	if (rc) {
534 		kfree(elfcorebuf);
535 		return rc;
536 	}
537 	rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
538 							&vmcore_list);
539 	if (rc) {
540 		kfree(elfcorebuf);
541 		return rc;
542 	}
543 	set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
544 	return 0;
545 }
546 
547 static int __init parse_crash_elf32_headers(void)
548 {
549 	int rc=0;
550 	Elf32_Ehdr ehdr;
551 	u64 addr;
552 
553 	addr = elfcorehdr_addr;
554 
555 	/* Read Elf header */
556 	rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
557 	if (rc < 0)
558 		return rc;
559 
560 	/* Do some basic Verification. */
561 	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
562 		(ehdr.e_type != ET_CORE) ||
563 		!elf_check_arch(&ehdr) ||
564 		ehdr.e_ident[EI_CLASS] != ELFCLASS32||
565 		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
566 		ehdr.e_version != EV_CURRENT ||
567 		ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
568 		ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
569 		ehdr.e_phnum == 0) {
570 		printk(KERN_WARNING "Warning: Core image elf header is not"
571 					"sane\n");
572 		return -EINVAL;
573 	}
574 
575 	/* Read in all elf headers. */
576 	elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
577 	elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
578 	if (!elfcorebuf)
579 		return -ENOMEM;
580 	addr = elfcorehdr_addr;
581 	rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
582 	if (rc < 0) {
583 		kfree(elfcorebuf);
584 		return rc;
585 	}
586 
587 	/* Merge all PT_NOTE headers into one. */
588 	rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
589 	if (rc) {
590 		kfree(elfcorebuf);
591 		return rc;
592 	}
593 	rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
594 								&vmcore_list);
595 	if (rc) {
596 		kfree(elfcorebuf);
597 		return rc;
598 	}
599 	set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
600 	return 0;
601 }
602 
603 static int __init parse_crash_elf_headers(void)
604 {
605 	unsigned char e_ident[EI_NIDENT];
606 	u64 addr;
607 	int rc=0;
608 
609 	addr = elfcorehdr_addr;
610 	rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
611 	if (rc < 0)
612 		return rc;
613 	if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
614 		printk(KERN_WARNING "Warning: Core image elf header"
615 					" not found\n");
616 		return -EINVAL;
617 	}
618 
619 	if (e_ident[EI_CLASS] == ELFCLASS64) {
620 		rc = parse_crash_elf64_headers();
621 		if (rc)
622 			return rc;
623 
624 		/* Determine vmcore size. */
625 		vmcore_size = get_vmcore_size_elf64(elfcorebuf);
626 	} else if (e_ident[EI_CLASS] == ELFCLASS32) {
627 		rc = parse_crash_elf32_headers();
628 		if (rc)
629 			return rc;
630 
631 		/* Determine vmcore size. */
632 		vmcore_size = get_vmcore_size_elf32(elfcorebuf);
633 	} else {
634 		printk(KERN_WARNING "Warning: Core image elf header is not"
635 					" sane\n");
636 		return -EINVAL;
637 	}
638 	return 0;
639 }
640 
641 /* Init function for vmcore module. */
642 static int __init vmcore_init(void)
643 {
644 	int rc = 0;
645 
646 	/* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
647 	if (!(is_vmcore_usable()))
648 		return rc;
649 	rc = parse_crash_elf_headers();
650 	if (rc) {
651 		printk(KERN_WARNING "Kdump: vmcore not initialized\n");
652 		return rc;
653 	}
654 
655 	proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
656 	if (proc_vmcore)
657 		proc_vmcore->size = vmcore_size;
658 	return 0;
659 }
660 module_init(vmcore_init)
661