xref: /linux/fs/proc/vmcore.c (revision 87a132e73910e8689902aed7f2fc229d6908383b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *	fs/proc/vmcore.c Interface for accessing the crash
4  * 				 dump from the system's previous life.
5  * 	Heavily borrowed from fs/proc/kcore.c
6  *	Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
7  *	Copyright (C) IBM Corporation, 2004. All rights reserved
8  *
9  */
10 
11 #define pr_fmt(fmt) "vmcore: " fmt
12 
13 #include <linux/mm.h>
14 #include <linux/kcore.h>
15 #include <linux/user.h>
16 #include <linux/elf.h>
17 #include <linux/elfcore.h>
18 #include <linux/export.h>
19 #include <linux/slab.h>
20 #include <linux/highmem.h>
21 #include <linux/printk.h>
22 #include <linux/memblock.h>
23 #include <linux/init.h>
24 #include <linux/crash_dump.h>
25 #include <linux/list.h>
26 #include <linux/moduleparam.h>
27 #include <linux/mutex.h>
28 #include <linux/vmalloc.h>
29 #include <linux/pagemap.h>
30 #include <linux/uio.h>
31 #include <linux/cc_platform.h>
32 #include <asm/io.h>
33 #include "internal.h"
34 
35 /* List representing chunks of contiguous memory areas and their offsets in
36  * vmcore file.
37  */
38 static LIST_HEAD(vmcore_list);
39 
40 /* Stores the pointer to the buffer containing kernel elf core headers. */
41 static char *elfcorebuf;
42 static size_t elfcorebuf_sz;
43 static size_t elfcorebuf_sz_orig;
44 
45 static char *elfnotes_buf;
46 static size_t elfnotes_sz;
47 /* Size of all notes minus the device dump notes */
48 static size_t elfnotes_orig_sz;
49 
50 /* Total size of vmcore file. */
51 static u64 vmcore_size;
52 
53 static struct proc_dir_entry *proc_vmcore;
54 
55 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
56 struct vmcoredd_node {
57 	struct list_head list;	/* List of dumps */
58 	void *buf;		/* Buffer containing device's dump */
59 	unsigned int size;	/* Size of the buffer */
60 };
61 
62 /* Device Dump list and mutex to synchronize access to list */
63 static LIST_HEAD(vmcoredd_list);
64 
65 static bool vmcoredd_disabled;
66 core_param(novmcoredd, vmcoredd_disabled, bool, 0);
67 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
68 
69 /* Device Dump Size */
70 static size_t vmcoredd_orig_sz;
71 
72 static DEFINE_MUTEX(vmcore_mutex);
73 
74 DEFINE_STATIC_SRCU(vmcore_cb_srcu);
75 /* List of registered vmcore callbacks. */
76 static LIST_HEAD(vmcore_cb_list);
77 /* Whether the vmcore has been opened once. */
78 static bool vmcore_opened;
79 /* Whether the vmcore is currently open. */
80 static unsigned int vmcore_open;
81 
82 static void vmcore_process_device_ram(struct vmcore_cb *cb);
83 
register_vmcore_cb(struct vmcore_cb * cb)84 void register_vmcore_cb(struct vmcore_cb *cb)
85 {
86 	INIT_LIST_HEAD(&cb->next);
87 	mutex_lock(&vmcore_mutex);
88 	list_add_tail(&cb->next, &vmcore_cb_list);
89 	/*
90 	 * Registering a vmcore callback after the vmcore was opened is
91 	 * very unusual (e.g., manual driver loading).
92 	 */
93 	if (vmcore_opened)
94 		pr_warn_once("Unexpected vmcore callback registration\n");
95 	if (!vmcore_open && cb->get_device_ram)
96 		vmcore_process_device_ram(cb);
97 	mutex_unlock(&vmcore_mutex);
98 }
99 EXPORT_SYMBOL_GPL(register_vmcore_cb);
100 
unregister_vmcore_cb(struct vmcore_cb * cb)101 void unregister_vmcore_cb(struct vmcore_cb *cb)
102 {
103 	mutex_lock(&vmcore_mutex);
104 	list_del_rcu(&cb->next);
105 	/*
106 	 * Unregistering a vmcore callback after the vmcore was opened is
107 	 * very unusual (e.g., forced driver removal), but we cannot stop
108 	 * unregistering.
109 	 */
110 	if (vmcore_opened)
111 		pr_warn_once("Unexpected vmcore callback unregistration\n");
112 	mutex_unlock(&vmcore_mutex);
113 
114 	synchronize_srcu(&vmcore_cb_srcu);
115 }
116 EXPORT_SYMBOL_GPL(unregister_vmcore_cb);
117 
pfn_is_ram(unsigned long pfn)118 static bool pfn_is_ram(unsigned long pfn)
119 {
120 	struct vmcore_cb *cb;
121 	bool ret = true;
122 
123 	list_for_each_entry_srcu(cb, &vmcore_cb_list, next,
124 				 srcu_read_lock_held(&vmcore_cb_srcu)) {
125 		if (unlikely(!cb->pfn_is_ram))
126 			continue;
127 		ret = cb->pfn_is_ram(cb, pfn);
128 		if (!ret)
129 			break;
130 	}
131 
132 	return ret;
133 }
134 
open_vmcore(struct inode * inode,struct file * file)135 static int open_vmcore(struct inode *inode, struct file *file)
136 {
137 	mutex_lock(&vmcore_mutex);
138 	vmcore_opened = true;
139 	if (vmcore_open + 1 == 0) {
140 		mutex_unlock(&vmcore_mutex);
141 		return -EBUSY;
142 	}
143 	vmcore_open++;
144 	mutex_unlock(&vmcore_mutex);
145 
146 	return 0;
147 }
148 
release_vmcore(struct inode * inode,struct file * file)149 static int release_vmcore(struct inode *inode, struct file *file)
150 {
151 	mutex_lock(&vmcore_mutex);
152 	vmcore_open--;
153 	mutex_unlock(&vmcore_mutex);
154 
155 	return 0;
156 }
157 
158 /* Reads a page from the oldmem device from given offset. */
read_from_oldmem(struct iov_iter * iter,size_t count,u64 * ppos,bool encrypted)159 ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
160 			 u64 *ppos, bool encrypted)
161 {
162 	unsigned long pfn, offset;
163 	ssize_t nr_bytes;
164 	ssize_t read = 0, tmp;
165 	int idx;
166 
167 	if (!count)
168 		return 0;
169 
170 	offset = (unsigned long)(*ppos % PAGE_SIZE);
171 	pfn = (unsigned long)(*ppos / PAGE_SIZE);
172 
173 	idx = srcu_read_lock(&vmcore_cb_srcu);
174 	do {
175 		if (count > (PAGE_SIZE - offset))
176 			nr_bytes = PAGE_SIZE - offset;
177 		else
178 			nr_bytes = count;
179 
180 		/* If pfn is not ram, return zeros for sparse dump files */
181 		if (!pfn_is_ram(pfn)) {
182 			tmp = iov_iter_zero(nr_bytes, iter);
183 		} else {
184 			if (encrypted)
185 				tmp = copy_oldmem_page_encrypted(iter, pfn,
186 								 nr_bytes,
187 								 offset);
188 			else
189 				tmp = copy_oldmem_page(iter, pfn, nr_bytes,
190 						       offset);
191 		}
192 		if (tmp < nr_bytes) {
193 			srcu_read_unlock(&vmcore_cb_srcu, idx);
194 			return -EFAULT;
195 		}
196 
197 		*ppos += nr_bytes;
198 		count -= nr_bytes;
199 		read += nr_bytes;
200 		++pfn;
201 		offset = 0;
202 	} while (count);
203 	srcu_read_unlock(&vmcore_cb_srcu, idx);
204 
205 	return read;
206 }
207 
208 /*
209  * Architectures may override this function to allocate ELF header in 2nd kernel
210  */
elfcorehdr_alloc(unsigned long long * addr,unsigned long long * size)211 int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
212 {
213 	return 0;
214 }
215 
216 /*
217  * Architectures may override this function to free header
218  */
elfcorehdr_free(unsigned long long addr)219 void __weak elfcorehdr_free(unsigned long long addr)
220 {}
221 
222 /*
223  * Architectures may override this function to read from ELF header
224  */
elfcorehdr_read(char * buf,size_t count,u64 * ppos)225 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
226 {
227 	struct kvec kvec = { .iov_base = buf, .iov_len = count };
228 	struct iov_iter iter;
229 
230 	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
231 
232 	return read_from_oldmem(&iter, count, ppos, false);
233 }
234 
235 /*
236  * Architectures may override this function to read from notes sections
237  */
elfcorehdr_read_notes(char * buf,size_t count,u64 * ppos)238 ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
239 {
240 	struct kvec kvec = { .iov_base = buf, .iov_len = count };
241 	struct iov_iter iter;
242 
243 	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
244 
245 	return read_from_oldmem(&iter, count, ppos,
246 			cc_platform_has(CC_ATTR_MEM_ENCRYPT));
247 }
248 
249 /*
250  * Architectures may override this function to map oldmem
251  */
remap_oldmem_pfn_range(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)252 int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
253 				  unsigned long from, unsigned long pfn,
254 				  unsigned long size, pgprot_t prot)
255 {
256 	prot = pgprot_encrypted(prot);
257 	return remap_pfn_range(vma, from, pfn, size, prot);
258 }
259 
260 /*
261  * Architectures which support memory encryption override this.
262  */
copy_oldmem_page_encrypted(struct iov_iter * iter,unsigned long pfn,size_t csize,unsigned long offset)263 ssize_t __weak copy_oldmem_page_encrypted(struct iov_iter *iter,
264 		unsigned long pfn, size_t csize, unsigned long offset)
265 {
266 	return copy_oldmem_page(iter, pfn, csize, offset);
267 }
268 
269 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
vmcoredd_copy_dumps(struct iov_iter * iter,u64 start,size_t size)270 static int vmcoredd_copy_dumps(struct iov_iter *iter, u64 start, size_t size)
271 {
272 	struct vmcoredd_node *dump;
273 	u64 offset = 0;
274 	size_t tsz;
275 	char *buf;
276 
277 	list_for_each_entry(dump, &vmcoredd_list, list) {
278 		if (start < offset + dump->size) {
279 			tsz = min(offset + (u64)dump->size - start, (u64)size);
280 			buf = dump->buf + start - offset;
281 			if (copy_to_iter(buf, tsz, iter) < tsz)
282 				return -EFAULT;
283 
284 			size -= tsz;
285 			start += tsz;
286 
287 			/* Leave now if buffer filled already */
288 			if (!size)
289 				return 0;
290 		}
291 		offset += dump->size;
292 	}
293 
294 	return 0;
295 }
296 
297 #ifdef CONFIG_MMU
vmcoredd_mmap_dumps(struct vm_area_struct * vma,unsigned long dst,u64 start,size_t size)298 static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst,
299 			       u64 start, size_t size)
300 {
301 	struct vmcoredd_node *dump;
302 	u64 offset = 0;
303 	size_t tsz;
304 	char *buf;
305 
306 	list_for_each_entry(dump, &vmcoredd_list, list) {
307 		if (start < offset + dump->size) {
308 			tsz = min(offset + (u64)dump->size - start, (u64)size);
309 			buf = dump->buf + start - offset;
310 			if (remap_vmalloc_range_partial(vma, dst, buf, 0,
311 							tsz))
312 				return -EFAULT;
313 
314 			size -= tsz;
315 			start += tsz;
316 			dst += tsz;
317 
318 			/* Leave now if buffer filled already */
319 			if (!size)
320 				return 0;
321 		}
322 		offset += dump->size;
323 	}
324 
325 	return 0;
326 }
327 #endif /* CONFIG_MMU */
328 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
329 
330 /* Read from the ELF header and then the crash dump. On error, negative value is
331  * returned otherwise number of bytes read are returned.
332  */
__read_vmcore(struct iov_iter * iter,loff_t * fpos)333 static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos)
334 {
335 	struct vmcore_range *m = NULL;
336 	ssize_t acc = 0, tmp;
337 	size_t tsz;
338 	u64 start;
339 
340 	if (!iov_iter_count(iter) || *fpos >= vmcore_size)
341 		return 0;
342 
343 	iov_iter_truncate(iter, vmcore_size - *fpos);
344 
345 	/* Read ELF core header */
346 	if (*fpos < elfcorebuf_sz) {
347 		tsz = min(elfcorebuf_sz - (size_t)*fpos, iov_iter_count(iter));
348 		if (copy_to_iter(elfcorebuf + *fpos, tsz, iter) < tsz)
349 			return -EFAULT;
350 		*fpos += tsz;
351 		acc += tsz;
352 
353 		/* leave now if filled buffer already */
354 		if (!iov_iter_count(iter))
355 			return acc;
356 	}
357 
358 	/* Read ELF note segment */
359 	if (*fpos < elfcorebuf_sz + elfnotes_sz) {
360 		void *kaddr;
361 
362 		/* We add device dumps before other elf notes because the
363 		 * other elf notes may not fill the elf notes buffer
364 		 * completely and we will end up with zero-filled data
365 		 * between the elf notes and the device dumps. Tools will
366 		 * then try to decode this zero-filled data as valid notes
367 		 * and we don't want that. Hence, adding device dumps before
368 		 * the other elf notes ensure that zero-filled data can be
369 		 * avoided.
370 		 */
371 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
372 		/* Read device dumps */
373 		if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
374 			tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
375 				  (size_t)*fpos, iov_iter_count(iter));
376 			start = *fpos - elfcorebuf_sz;
377 			if (vmcoredd_copy_dumps(iter, start, tsz))
378 				return -EFAULT;
379 
380 			*fpos += tsz;
381 			acc += tsz;
382 
383 			/* leave now if filled buffer already */
384 			if (!iov_iter_count(iter))
385 				return acc;
386 		}
387 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
388 
389 		/* Read remaining elf notes */
390 		tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos,
391 			  iov_iter_count(iter));
392 		kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
393 		if (copy_to_iter(kaddr, tsz, iter) < tsz)
394 			return -EFAULT;
395 
396 		*fpos += tsz;
397 		acc += tsz;
398 
399 		/* leave now if filled buffer already */
400 		if (!iov_iter_count(iter))
401 			return acc;
402 
403 		cond_resched();
404 	}
405 
406 	list_for_each_entry(m, &vmcore_list, list) {
407 		if (*fpos < m->offset + m->size) {
408 			tsz = (size_t)min_t(unsigned long long,
409 					    m->offset + m->size - *fpos,
410 					    iov_iter_count(iter));
411 			start = m->paddr + *fpos - m->offset;
412 			tmp = read_from_oldmem(iter, tsz, &start,
413 					cc_platform_has(CC_ATTR_MEM_ENCRYPT));
414 			if (tmp < 0)
415 				return tmp;
416 			*fpos += tsz;
417 			acc += tsz;
418 
419 			/* leave now if filled buffer already */
420 			if (!iov_iter_count(iter))
421 				return acc;
422 		}
423 
424 		cond_resched();
425 	}
426 
427 	return acc;
428 }
429 
read_vmcore(struct kiocb * iocb,struct iov_iter * iter)430 static ssize_t read_vmcore(struct kiocb *iocb, struct iov_iter *iter)
431 {
432 	return __read_vmcore(iter, &iocb->ki_pos);
433 }
434 
435 /**
436  * vmcore_alloc_buf - allocate buffer in vmalloc memory
437  * @size: size of buffer
438  *
439  * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
440  * the buffer to user-space by means of remap_vmalloc_range().
441  *
442  * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
443  * disabled and there's no need to allow users to mmap the buffer.
444  */
vmcore_alloc_buf(size_t size)445 static inline char *vmcore_alloc_buf(size_t size)
446 {
447 #ifdef CONFIG_MMU
448 	return vmalloc_user(size);
449 #else
450 	return vzalloc(size);
451 #endif
452 }
453 
454 /*
455  * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
456  * essential for mmap_vmcore() in order to map physically
457  * non-contiguous objects (ELF header, ELF note segment and memory
458  * regions in the 1st kernel pointed to by PT_LOAD entries) into
459  * virtually contiguous user-space in ELF layout.
460  */
461 #ifdef CONFIG_MMU
462 
463 /*
464  * The vmcore fault handler uses the page cache and fills data using the
465  * standard __read_vmcore() function.
466  *
467  * On s390 the fault handler is used for memory regions that can't be mapped
468  * directly with remap_pfn_range().
469  */
mmap_vmcore_fault(struct vm_fault * vmf)470 static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
471 {
472 #ifdef CONFIG_S390
473 	struct address_space *mapping = vmf->vma->vm_file->f_mapping;
474 	pgoff_t index = vmf->pgoff;
475 	struct iov_iter iter;
476 	struct kvec kvec;
477 	struct page *page;
478 	loff_t offset;
479 	int rc;
480 
481 	page = find_or_create_page(mapping, index, GFP_KERNEL);
482 	if (!page)
483 		return VM_FAULT_OOM;
484 	if (!PageUptodate(page)) {
485 		offset = (loff_t) index << PAGE_SHIFT;
486 		kvec.iov_base = page_address(page);
487 		kvec.iov_len = PAGE_SIZE;
488 		iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, PAGE_SIZE);
489 
490 		rc = __read_vmcore(&iter, &offset);
491 		if (rc < 0) {
492 			unlock_page(page);
493 			put_page(page);
494 			return vmf_error(rc);
495 		}
496 		SetPageUptodate(page);
497 	}
498 	unlock_page(page);
499 	vmf->page = page;
500 	return 0;
501 #else
502 	return VM_FAULT_SIGBUS;
503 #endif
504 }
505 
506 static const struct vm_operations_struct vmcore_mmap_ops = {
507 	.fault = mmap_vmcore_fault,
508 };
509 
510 /*
511  * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
512  * reported as not being ram with the zero page.
513  *
514  * @vma: vm_area_struct describing requested mapping
515  * @from: start remapping from
516  * @pfn: page frame number to start remapping to
517  * @size: remapping size
518  * @prot: protection bits
519  *
520  * Returns zero on success, -EAGAIN on failure.
521  */
remap_oldmem_pfn_checked(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)522 static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
523 				    unsigned long from, unsigned long pfn,
524 				    unsigned long size, pgprot_t prot)
525 {
526 	unsigned long map_size;
527 	unsigned long pos_start, pos_end, pos;
528 	unsigned long zeropage_pfn = my_zero_pfn(0);
529 	size_t len = 0;
530 
531 	pos_start = pfn;
532 	pos_end = pfn + (size >> PAGE_SHIFT);
533 
534 	for (pos = pos_start; pos < pos_end; ++pos) {
535 		if (!pfn_is_ram(pos)) {
536 			/*
537 			 * We hit a page which is not ram. Remap the continuous
538 			 * region between pos_start and pos-1 and replace
539 			 * the non-ram page at pos with the zero page.
540 			 */
541 			if (pos > pos_start) {
542 				/* Remap continuous region */
543 				map_size = (pos - pos_start) << PAGE_SHIFT;
544 				if (remap_oldmem_pfn_range(vma, from + len,
545 							   pos_start, map_size,
546 							   prot))
547 					goto fail;
548 				len += map_size;
549 			}
550 			/* Remap the zero page */
551 			if (remap_oldmem_pfn_range(vma, from + len,
552 						   zeropage_pfn,
553 						   PAGE_SIZE, prot))
554 				goto fail;
555 			len += PAGE_SIZE;
556 			pos_start = pos + 1;
557 		}
558 	}
559 	if (pos > pos_start) {
560 		/* Remap the rest */
561 		map_size = (pos - pos_start) << PAGE_SHIFT;
562 		if (remap_oldmem_pfn_range(vma, from + len, pos_start,
563 					   map_size, prot))
564 			goto fail;
565 	}
566 	return 0;
567 fail:
568 	do_munmap(vma->vm_mm, from, len, NULL);
569 	return -EAGAIN;
570 }
571 
vmcore_remap_oldmem_pfn(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)572 static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
573 			    unsigned long from, unsigned long pfn,
574 			    unsigned long size, pgprot_t prot)
575 {
576 	int ret, idx;
577 
578 	/*
579 	 * Check if a callback was registered to avoid looping over all
580 	 * pages without a reason.
581 	 */
582 	idx = srcu_read_lock(&vmcore_cb_srcu);
583 	if (!list_empty(&vmcore_cb_list))
584 		ret = remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
585 	else
586 		ret = remap_oldmem_pfn_range(vma, from, pfn, size, prot);
587 	srcu_read_unlock(&vmcore_cb_srcu, idx);
588 	return ret;
589 }
590 
mmap_vmcore(struct file * file,struct vm_area_struct * vma)591 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
592 {
593 	size_t size = vma->vm_end - vma->vm_start;
594 	u64 start, end, len, tsz;
595 	struct vmcore_range *m;
596 
597 	start = (u64)vma->vm_pgoff << PAGE_SHIFT;
598 	end = start + size;
599 
600 	if (size > vmcore_size || end > vmcore_size)
601 		return -EINVAL;
602 
603 	if (vma->vm_flags & (VM_WRITE | VM_EXEC))
604 		return -EPERM;
605 
606 	vm_flags_mod(vma, VM_MIXEDMAP, VM_MAYWRITE | VM_MAYEXEC);
607 	vma->vm_ops = &vmcore_mmap_ops;
608 
609 	len = 0;
610 
611 	if (start < elfcorebuf_sz) {
612 		u64 pfn;
613 
614 		tsz = min(elfcorebuf_sz - (size_t)start, size);
615 		pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
616 		if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
617 				    vma->vm_page_prot))
618 			return -EAGAIN;
619 		size -= tsz;
620 		start += tsz;
621 		len += tsz;
622 
623 		if (size == 0)
624 			return 0;
625 	}
626 
627 	if (start < elfcorebuf_sz + elfnotes_sz) {
628 		void *kaddr;
629 
630 		/* We add device dumps before other elf notes because the
631 		 * other elf notes may not fill the elf notes buffer
632 		 * completely and we will end up with zero-filled data
633 		 * between the elf notes and the device dumps. Tools will
634 		 * then try to decode this zero-filled data as valid notes
635 		 * and we don't want that. Hence, adding device dumps before
636 		 * the other elf notes ensure that zero-filled data can be
637 		 * avoided. This also ensures that the device dumps and
638 		 * other elf notes can be properly mmaped at page aligned
639 		 * address.
640 		 */
641 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
642 		/* Read device dumps */
643 		if (start < elfcorebuf_sz + vmcoredd_orig_sz) {
644 			u64 start_off;
645 
646 			tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
647 				  (size_t)start, size);
648 			start_off = start - elfcorebuf_sz;
649 			if (vmcoredd_mmap_dumps(vma, vma->vm_start + len,
650 						start_off, tsz))
651 				goto fail;
652 
653 			size -= tsz;
654 			start += tsz;
655 			len += tsz;
656 
657 			/* leave now if filled buffer already */
658 			if (!size)
659 				return 0;
660 		}
661 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
662 
663 		/* Read remaining elf notes */
664 		tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
665 		kaddr = elfnotes_buf + start - elfcorebuf_sz - vmcoredd_orig_sz;
666 		if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
667 						kaddr, 0, tsz))
668 			goto fail;
669 
670 		size -= tsz;
671 		start += tsz;
672 		len += tsz;
673 
674 		if (size == 0)
675 			return 0;
676 	}
677 
678 	list_for_each_entry(m, &vmcore_list, list) {
679 		if (start < m->offset + m->size) {
680 			u64 paddr = 0;
681 
682 			tsz = (size_t)min_t(unsigned long long,
683 					    m->offset + m->size - start, size);
684 			paddr = m->paddr + start - m->offset;
685 			if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
686 						    paddr >> PAGE_SHIFT, tsz,
687 						    vma->vm_page_prot))
688 				goto fail;
689 			size -= tsz;
690 			start += tsz;
691 			len += tsz;
692 
693 			if (size == 0)
694 				return 0;
695 		}
696 	}
697 
698 	return 0;
699 fail:
700 	do_munmap(vma->vm_mm, vma->vm_start, len, NULL);
701 	return -EAGAIN;
702 }
703 #else
mmap_vmcore(struct file * file,struct vm_area_struct * vma)704 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
705 {
706 	return -ENOSYS;
707 }
708 #endif
709 
710 static const struct proc_ops vmcore_proc_ops = {
711 	.proc_open	= open_vmcore,
712 	.proc_release	= release_vmcore,
713 	.proc_read_iter	= read_vmcore,
714 	.proc_lseek	= default_llseek,
715 	.proc_mmap	= mmap_vmcore,
716 };
717 
get_vmcore_size(size_t elfsz,size_t elfnotesegsz,struct list_head * vc_list)718 static u64 get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
719 			   struct list_head *vc_list)
720 {
721 	struct vmcore_range *m;
722 	u64 size;
723 
724 	size = elfsz + elfnotesegsz;
725 	list_for_each_entry(m, vc_list, list) {
726 		size += m->size;
727 	}
728 	return size;
729 }
730 
731 /**
732  * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
733  *
734  * @ehdr_ptr: ELF header
735  *
736  * This function updates p_memsz member of each PT_NOTE entry in the
737  * program header table pointed to by @ehdr_ptr to real size of ELF
738  * note segment.
739  */
update_note_header_size_elf64(const Elf64_Ehdr * ehdr_ptr)740 static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
741 {
742 	int i, rc=0;
743 	Elf64_Phdr *phdr_ptr;
744 	Elf64_Nhdr *nhdr_ptr;
745 
746 	phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
747 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
748 		void *notes_section;
749 		u64 offset, max_sz, sz, real_sz = 0;
750 		if (phdr_ptr->p_type != PT_NOTE)
751 			continue;
752 		max_sz = phdr_ptr->p_memsz;
753 		offset = phdr_ptr->p_offset;
754 		notes_section = kmalloc(max_sz, GFP_KERNEL);
755 		if (!notes_section)
756 			return -ENOMEM;
757 		rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
758 		if (rc < 0) {
759 			kfree(notes_section);
760 			return rc;
761 		}
762 		nhdr_ptr = notes_section;
763 		while (nhdr_ptr->n_namesz != 0) {
764 			sz = sizeof(Elf64_Nhdr) +
765 				(((u64)nhdr_ptr->n_namesz + 3) & ~3) +
766 				(((u64)nhdr_ptr->n_descsz + 3) & ~3);
767 			if ((real_sz + sz) > max_sz) {
768 				pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
769 					nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
770 				break;
771 			}
772 			real_sz += sz;
773 			nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
774 		}
775 		kfree(notes_section);
776 		phdr_ptr->p_memsz = real_sz;
777 		if (real_sz == 0) {
778 			pr_warn("Warning: Zero PT_NOTE entries found\n");
779 		}
780 	}
781 
782 	return 0;
783 }
784 
785 /**
786  * get_note_number_and_size_elf64 - get the number of PT_NOTE program
787  * headers and sum of real size of their ELF note segment headers and
788  * data.
789  *
790  * @ehdr_ptr: ELF header
791  * @nr_ptnote: buffer for the number of PT_NOTE program headers
792  * @sz_ptnote: buffer for size of unique PT_NOTE program header
793  *
794  * This function is used to merge multiple PT_NOTE program headers
795  * into a unique single one. The resulting unique entry will have
796  * @sz_ptnote in its phdr->p_mem.
797  *
798  * It is assumed that program headers with PT_NOTE type pointed to by
799  * @ehdr_ptr has already been updated by update_note_header_size_elf64
800  * and each of PT_NOTE program headers has actual ELF note segment
801  * size in its p_memsz member.
802  */
get_note_number_and_size_elf64(const Elf64_Ehdr * ehdr_ptr,int * nr_ptnote,u64 * sz_ptnote)803 static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
804 						 int *nr_ptnote, u64 *sz_ptnote)
805 {
806 	int i;
807 	Elf64_Phdr *phdr_ptr;
808 
809 	*nr_ptnote = *sz_ptnote = 0;
810 
811 	phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
812 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
813 		if (phdr_ptr->p_type != PT_NOTE)
814 			continue;
815 		*nr_ptnote += 1;
816 		*sz_ptnote += phdr_ptr->p_memsz;
817 	}
818 
819 	return 0;
820 }
821 
822 /**
823  * copy_notes_elf64 - copy ELF note segments in a given buffer
824  *
825  * @ehdr_ptr: ELF header
826  * @notes_buf: buffer into which ELF note segments are copied
827  *
828  * This function is used to copy ELF note segment in the 1st kernel
829  * into the buffer @notes_buf in the 2nd kernel. It is assumed that
830  * size of the buffer @notes_buf is equal to or larger than sum of the
831  * real ELF note segment headers and data.
832  *
833  * It is assumed that program headers with PT_NOTE type pointed to by
834  * @ehdr_ptr has already been updated by update_note_header_size_elf64
835  * and each of PT_NOTE program headers has actual ELF note segment
836  * size in its p_memsz member.
837  */
copy_notes_elf64(const Elf64_Ehdr * ehdr_ptr,char * notes_buf)838 static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
839 {
840 	int i, rc=0;
841 	Elf64_Phdr *phdr_ptr;
842 
843 	phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
844 
845 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
846 		u64 offset;
847 		if (phdr_ptr->p_type != PT_NOTE)
848 			continue;
849 		offset = phdr_ptr->p_offset;
850 		rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
851 					   &offset);
852 		if (rc < 0)
853 			return rc;
854 		notes_buf += phdr_ptr->p_memsz;
855 	}
856 
857 	return 0;
858 }
859 
860 /* Merges all the PT_NOTE headers into one. */
merge_note_headers_elf64(char * elfptr,size_t * elfsz,char ** notes_buf,size_t * notes_sz)861 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
862 					   char **notes_buf, size_t *notes_sz)
863 {
864 	int i, nr_ptnote=0, rc=0;
865 	char *tmp;
866 	Elf64_Ehdr *ehdr_ptr;
867 	Elf64_Phdr phdr;
868 	u64 phdr_sz = 0, note_off;
869 
870 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
871 
872 	rc = update_note_header_size_elf64(ehdr_ptr);
873 	if (rc < 0)
874 		return rc;
875 
876 	rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
877 	if (rc < 0)
878 		return rc;
879 
880 	*notes_sz = roundup(phdr_sz, PAGE_SIZE);
881 	*notes_buf = vmcore_alloc_buf(*notes_sz);
882 	if (!*notes_buf)
883 		return -ENOMEM;
884 
885 	rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
886 	if (rc < 0)
887 		return rc;
888 
889 	/* Prepare merged PT_NOTE program header. */
890 	phdr.p_type    = PT_NOTE;
891 	phdr.p_flags   = 0;
892 	note_off = sizeof(Elf64_Ehdr) +
893 			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
894 	phdr.p_offset  = roundup(note_off, PAGE_SIZE);
895 	phdr.p_vaddr   = phdr.p_paddr = 0;
896 	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
897 	phdr.p_align   = 4;
898 
899 	/* Add merged PT_NOTE program header*/
900 	tmp = elfptr + sizeof(Elf64_Ehdr);
901 	memcpy(tmp, &phdr, sizeof(phdr));
902 	tmp += sizeof(phdr);
903 
904 	/* Remove unwanted PT_NOTE program headers. */
905 	i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
906 	*elfsz = *elfsz - i;
907 	memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
908 	memset(elfptr + *elfsz, 0, i);
909 	*elfsz = roundup(*elfsz, PAGE_SIZE);
910 
911 	/* Modify e_phnum to reflect merged headers. */
912 	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
913 
914 	/* Store the size of all notes.  We need this to update the note
915 	 * header when the device dumps will be added.
916 	 */
917 	elfnotes_orig_sz = phdr.p_memsz;
918 
919 	return 0;
920 }
921 
922 /**
923  * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
924  *
925  * @ehdr_ptr: ELF header
926  *
927  * This function updates p_memsz member of each PT_NOTE entry in the
928  * program header table pointed to by @ehdr_ptr to real size of ELF
929  * note segment.
930  */
update_note_header_size_elf32(const Elf32_Ehdr * ehdr_ptr)931 static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
932 {
933 	int i, rc=0;
934 	Elf32_Phdr *phdr_ptr;
935 	Elf32_Nhdr *nhdr_ptr;
936 
937 	phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
938 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
939 		void *notes_section;
940 		u64 offset, max_sz, sz, real_sz = 0;
941 		if (phdr_ptr->p_type != PT_NOTE)
942 			continue;
943 		max_sz = phdr_ptr->p_memsz;
944 		offset = phdr_ptr->p_offset;
945 		notes_section = kmalloc(max_sz, GFP_KERNEL);
946 		if (!notes_section)
947 			return -ENOMEM;
948 		rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
949 		if (rc < 0) {
950 			kfree(notes_section);
951 			return rc;
952 		}
953 		nhdr_ptr = notes_section;
954 		while (nhdr_ptr->n_namesz != 0) {
955 			sz = sizeof(Elf32_Nhdr) +
956 				(((u64)nhdr_ptr->n_namesz + 3) & ~3) +
957 				(((u64)nhdr_ptr->n_descsz + 3) & ~3);
958 			if ((real_sz + sz) > max_sz) {
959 				pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
960 					nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
961 				break;
962 			}
963 			real_sz += sz;
964 			nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
965 		}
966 		kfree(notes_section);
967 		phdr_ptr->p_memsz = real_sz;
968 		if (real_sz == 0) {
969 			pr_warn("Warning: Zero PT_NOTE entries found\n");
970 		}
971 	}
972 
973 	return 0;
974 }
975 
976 /**
977  * get_note_number_and_size_elf32 - get the number of PT_NOTE program
978  * headers and sum of real size of their ELF note segment headers and
979  * data.
980  *
981  * @ehdr_ptr: ELF header
982  * @nr_ptnote: buffer for the number of PT_NOTE program headers
983  * @sz_ptnote: buffer for size of unique PT_NOTE program header
984  *
985  * This function is used to merge multiple PT_NOTE program headers
986  * into a unique single one. The resulting unique entry will have
987  * @sz_ptnote in its phdr->p_mem.
988  *
989  * It is assumed that program headers with PT_NOTE type pointed to by
990  * @ehdr_ptr has already been updated by update_note_header_size_elf32
991  * and each of PT_NOTE program headers has actual ELF note segment
992  * size in its p_memsz member.
993  */
get_note_number_and_size_elf32(const Elf32_Ehdr * ehdr_ptr,int * nr_ptnote,u64 * sz_ptnote)994 static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
995 						 int *nr_ptnote, u64 *sz_ptnote)
996 {
997 	int i;
998 	Elf32_Phdr *phdr_ptr;
999 
1000 	*nr_ptnote = *sz_ptnote = 0;
1001 
1002 	phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
1003 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1004 		if (phdr_ptr->p_type != PT_NOTE)
1005 			continue;
1006 		*nr_ptnote += 1;
1007 		*sz_ptnote += phdr_ptr->p_memsz;
1008 	}
1009 
1010 	return 0;
1011 }
1012 
1013 /**
1014  * copy_notes_elf32 - copy ELF note segments in a given buffer
1015  *
1016  * @ehdr_ptr: ELF header
1017  * @notes_buf: buffer into which ELF note segments are copied
1018  *
1019  * This function is used to copy ELF note segment in the 1st kernel
1020  * into the buffer @notes_buf in the 2nd kernel. It is assumed that
1021  * size of the buffer @notes_buf is equal to or larger than sum of the
1022  * real ELF note segment headers and data.
1023  *
1024  * It is assumed that program headers with PT_NOTE type pointed to by
1025  * @ehdr_ptr has already been updated by update_note_header_size_elf32
1026  * and each of PT_NOTE program headers has actual ELF note segment
1027  * size in its p_memsz member.
1028  */
copy_notes_elf32(const Elf32_Ehdr * ehdr_ptr,char * notes_buf)1029 static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
1030 {
1031 	int i, rc=0;
1032 	Elf32_Phdr *phdr_ptr;
1033 
1034 	phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
1035 
1036 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1037 		u64 offset;
1038 		if (phdr_ptr->p_type != PT_NOTE)
1039 			continue;
1040 		offset = phdr_ptr->p_offset;
1041 		rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
1042 					   &offset);
1043 		if (rc < 0)
1044 			return rc;
1045 		notes_buf += phdr_ptr->p_memsz;
1046 	}
1047 
1048 	return 0;
1049 }
1050 
1051 /* Merges all the PT_NOTE headers into one. */
merge_note_headers_elf32(char * elfptr,size_t * elfsz,char ** notes_buf,size_t * notes_sz)1052 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
1053 					   char **notes_buf, size_t *notes_sz)
1054 {
1055 	int i, nr_ptnote=0, rc=0;
1056 	char *tmp;
1057 	Elf32_Ehdr *ehdr_ptr;
1058 	Elf32_Phdr phdr;
1059 	u64 phdr_sz = 0, note_off;
1060 
1061 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
1062 
1063 	rc = update_note_header_size_elf32(ehdr_ptr);
1064 	if (rc < 0)
1065 		return rc;
1066 
1067 	rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
1068 	if (rc < 0)
1069 		return rc;
1070 
1071 	*notes_sz = roundup(phdr_sz, PAGE_SIZE);
1072 	*notes_buf = vmcore_alloc_buf(*notes_sz);
1073 	if (!*notes_buf)
1074 		return -ENOMEM;
1075 
1076 	rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
1077 	if (rc < 0)
1078 		return rc;
1079 
1080 	/* Prepare merged PT_NOTE program header. */
1081 	phdr.p_type    = PT_NOTE;
1082 	phdr.p_flags   = 0;
1083 	note_off = sizeof(Elf32_Ehdr) +
1084 			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
1085 	phdr.p_offset  = roundup(note_off, PAGE_SIZE);
1086 	phdr.p_vaddr   = phdr.p_paddr = 0;
1087 	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
1088 	phdr.p_align   = 4;
1089 
1090 	/* Add merged PT_NOTE program header*/
1091 	tmp = elfptr + sizeof(Elf32_Ehdr);
1092 	memcpy(tmp, &phdr, sizeof(phdr));
1093 	tmp += sizeof(phdr);
1094 
1095 	/* Remove unwanted PT_NOTE program headers. */
1096 	i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
1097 	*elfsz = *elfsz - i;
1098 	memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
1099 	memset(elfptr + *elfsz, 0, i);
1100 	*elfsz = roundup(*elfsz, PAGE_SIZE);
1101 
1102 	/* Modify e_phnum to reflect merged headers. */
1103 	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
1104 
1105 	/* Store the size of all notes.  We need this to update the note
1106 	 * header when the device dumps will be added.
1107 	 */
1108 	elfnotes_orig_sz = phdr.p_memsz;
1109 
1110 	return 0;
1111 }
1112 
1113 /* Add memory chunks represented by program headers to vmcore list. Also update
1114  * the new offset fields of exported program headers. */
process_ptload_program_headers_elf64(char * elfptr,size_t elfsz,size_t elfnotes_sz,struct list_head * vc_list)1115 static int __init process_ptload_program_headers_elf64(char *elfptr,
1116 						size_t elfsz,
1117 						size_t elfnotes_sz,
1118 						struct list_head *vc_list)
1119 {
1120 	int i;
1121 	Elf64_Ehdr *ehdr_ptr;
1122 	Elf64_Phdr *phdr_ptr;
1123 	loff_t vmcore_off;
1124 
1125 	ehdr_ptr = (Elf64_Ehdr *)elfptr;
1126 	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
1127 
1128 	/* Skip ELF header, program headers and ELF note segment. */
1129 	vmcore_off = elfsz + elfnotes_sz;
1130 
1131 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1132 		u64 paddr, start, end, size;
1133 
1134 		if (phdr_ptr->p_type != PT_LOAD)
1135 			continue;
1136 
1137 		paddr = phdr_ptr->p_offset;
1138 		start = rounddown(paddr, PAGE_SIZE);
1139 		end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1140 		size = end - start;
1141 
1142 		if (vmcore_alloc_add_range(vc_list, start, size))
1143 			return -ENOMEM;
1144 
1145 		/* Update the program header offset. */
1146 		phdr_ptr->p_offset = vmcore_off + (paddr - start);
1147 		vmcore_off = vmcore_off + size;
1148 	}
1149 	return 0;
1150 }
1151 
process_ptload_program_headers_elf32(char * elfptr,size_t elfsz,size_t elfnotes_sz,struct list_head * vc_list)1152 static int __init process_ptload_program_headers_elf32(char *elfptr,
1153 						size_t elfsz,
1154 						size_t elfnotes_sz,
1155 						struct list_head *vc_list)
1156 {
1157 	int i;
1158 	Elf32_Ehdr *ehdr_ptr;
1159 	Elf32_Phdr *phdr_ptr;
1160 	loff_t vmcore_off;
1161 
1162 	ehdr_ptr = (Elf32_Ehdr *)elfptr;
1163 	phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
1164 
1165 	/* Skip ELF header, program headers and ELF note segment. */
1166 	vmcore_off = elfsz + elfnotes_sz;
1167 
1168 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1169 		u64 paddr, start, end, size;
1170 
1171 		if (phdr_ptr->p_type != PT_LOAD)
1172 			continue;
1173 
1174 		paddr = phdr_ptr->p_offset;
1175 		start = rounddown(paddr, PAGE_SIZE);
1176 		end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1177 		size = end - start;
1178 
1179 		if (vmcore_alloc_add_range(vc_list, start, size))
1180 			return -ENOMEM;
1181 
1182 		/* Update the program header offset */
1183 		phdr_ptr->p_offset = vmcore_off + (paddr - start);
1184 		vmcore_off = vmcore_off + size;
1185 	}
1186 	return 0;
1187 }
1188 
1189 /* Sets offset fields of vmcore elements. */
set_vmcore_list_offsets(size_t elfsz,size_t elfnotes_sz,struct list_head * vc_list)1190 static void set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
1191 				    struct list_head *vc_list)
1192 {
1193 	struct vmcore_range *m;
1194 	loff_t vmcore_off;
1195 
1196 	/* Skip ELF header, program headers and ELF note segment. */
1197 	vmcore_off = elfsz + elfnotes_sz;
1198 
1199 	list_for_each_entry(m, vc_list, list) {
1200 		m->offset = vmcore_off;
1201 		vmcore_off += m->size;
1202 	}
1203 }
1204 
free_elfcorebuf(void)1205 static void free_elfcorebuf(void)
1206 {
1207 	free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
1208 	elfcorebuf = NULL;
1209 	vfree(elfnotes_buf);
1210 	elfnotes_buf = NULL;
1211 }
1212 
parse_crash_elf64_headers(void)1213 static int __init parse_crash_elf64_headers(void)
1214 {
1215 	int rc=0;
1216 	Elf64_Ehdr ehdr;
1217 	u64 addr;
1218 
1219 	addr = elfcorehdr_addr;
1220 
1221 	/* Read ELF header */
1222 	rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
1223 	if (rc < 0)
1224 		return rc;
1225 
1226 	/* Do some basic Verification. */
1227 	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1228 		(ehdr.e_type != ET_CORE) ||
1229 		!vmcore_elf64_check_arch(&ehdr) ||
1230 		ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
1231 		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1232 		ehdr.e_version != EV_CURRENT ||
1233 		ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
1234 		ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
1235 		ehdr.e_phnum == 0) {
1236 		pr_warn("Warning: Core image elf header is not sane\n");
1237 		return -EINVAL;
1238 	}
1239 
1240 	/* Read in all elf headers. */
1241 	elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
1242 				ehdr.e_phnum * sizeof(Elf64_Phdr);
1243 	elfcorebuf_sz = elfcorebuf_sz_orig;
1244 	elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1245 					      get_order(elfcorebuf_sz_orig));
1246 	if (!elfcorebuf)
1247 		return -ENOMEM;
1248 	addr = elfcorehdr_addr;
1249 	rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1250 	if (rc < 0)
1251 		goto fail;
1252 
1253 	/* Merge all PT_NOTE headers into one. */
1254 	rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
1255 				      &elfnotes_buf, &elfnotes_sz);
1256 	if (rc)
1257 		goto fail;
1258 	rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
1259 						  elfnotes_sz, &vmcore_list);
1260 	if (rc)
1261 		goto fail;
1262 	set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1263 	return 0;
1264 fail:
1265 	free_elfcorebuf();
1266 	return rc;
1267 }
1268 
parse_crash_elf32_headers(void)1269 static int __init parse_crash_elf32_headers(void)
1270 {
1271 	int rc=0;
1272 	Elf32_Ehdr ehdr;
1273 	u64 addr;
1274 
1275 	addr = elfcorehdr_addr;
1276 
1277 	/* Read ELF header */
1278 	rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
1279 	if (rc < 0)
1280 		return rc;
1281 
1282 	/* Do some basic Verification. */
1283 	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1284 		(ehdr.e_type != ET_CORE) ||
1285 		!vmcore_elf32_check_arch(&ehdr) ||
1286 		ehdr.e_ident[EI_CLASS] != ELFCLASS32||
1287 		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1288 		ehdr.e_version != EV_CURRENT ||
1289 		ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1290 		ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1291 		ehdr.e_phnum == 0) {
1292 		pr_warn("Warning: Core image elf header is not sane\n");
1293 		return -EINVAL;
1294 	}
1295 
1296 	/* Read in all elf headers. */
1297 	elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1298 	elfcorebuf_sz = elfcorebuf_sz_orig;
1299 	elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1300 					      get_order(elfcorebuf_sz_orig));
1301 	if (!elfcorebuf)
1302 		return -ENOMEM;
1303 	addr = elfcorehdr_addr;
1304 	rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1305 	if (rc < 0)
1306 		goto fail;
1307 
1308 	/* Merge all PT_NOTE headers into one. */
1309 	rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1310 				      &elfnotes_buf, &elfnotes_sz);
1311 	if (rc)
1312 		goto fail;
1313 	rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1314 						  elfnotes_sz, &vmcore_list);
1315 	if (rc)
1316 		goto fail;
1317 	set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1318 	return 0;
1319 fail:
1320 	free_elfcorebuf();
1321 	return rc;
1322 }
1323 
parse_crash_elf_headers(void)1324 static int __init parse_crash_elf_headers(void)
1325 {
1326 	unsigned char e_ident[EI_NIDENT];
1327 	u64 addr;
1328 	int rc=0;
1329 
1330 	addr = elfcorehdr_addr;
1331 	rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1332 	if (rc < 0)
1333 		return rc;
1334 	if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1335 		pr_warn("Warning: Core image elf header not found\n");
1336 		return -EINVAL;
1337 	}
1338 
1339 	if (e_ident[EI_CLASS] == ELFCLASS64) {
1340 		rc = parse_crash_elf64_headers();
1341 		if (rc)
1342 			return rc;
1343 	} else if (e_ident[EI_CLASS] == ELFCLASS32) {
1344 		rc = parse_crash_elf32_headers();
1345 		if (rc)
1346 			return rc;
1347 	} else {
1348 		pr_warn("Warning: Core image elf header is not sane\n");
1349 		return -EINVAL;
1350 	}
1351 
1352 	/* Determine vmcore size. */
1353 	vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1354 				      &vmcore_list);
1355 
1356 	return 0;
1357 }
1358 
1359 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1360 /**
1361  * vmcoredd_write_header - Write vmcore device dump header at the
1362  * beginning of the dump's buffer.
1363  * @buf: Output buffer where the note is written
1364  * @data: Dump info
1365  * @size: Size of the dump
1366  *
1367  * Fills beginning of the dump's buffer with vmcore device dump header.
1368  */
vmcoredd_write_header(void * buf,struct vmcoredd_data * data,u32 size)1369 static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data,
1370 				  u32 size)
1371 {
1372 	struct vmcoredd_header *vdd_hdr = (struct vmcoredd_header *)buf;
1373 
1374 	vdd_hdr->n_namesz = sizeof(vdd_hdr->name);
1375 	vdd_hdr->n_descsz = size + sizeof(vdd_hdr->dump_name);
1376 	vdd_hdr->n_type = NT_VMCOREDD;
1377 
1378 	strscpy_pad(vdd_hdr->name, VMCOREDD_NOTE_NAME);
1379 	strscpy_pad(vdd_hdr->dump_name, data->dump_name);
1380 }
1381 
1382 /**
1383  * vmcoredd_update_program_headers - Update all ELF program headers
1384  * @elfptr: Pointer to elf header
1385  * @elfnotesz: Size of elf notes aligned to page size
1386  * @vmcoreddsz: Size of device dumps to be added to elf note header
1387  *
1388  * Determine type of ELF header (Elf64 or Elf32) and update the elf note size.
1389  * Also update the offsets of all the program headers after the elf note header.
1390  */
vmcoredd_update_program_headers(char * elfptr,size_t elfnotesz,size_t vmcoreddsz)1391 static void vmcoredd_update_program_headers(char *elfptr, size_t elfnotesz,
1392 					    size_t vmcoreddsz)
1393 {
1394 	unsigned char *e_ident = (unsigned char *)elfptr;
1395 	u64 start, end, size;
1396 	loff_t vmcore_off;
1397 	u32 i;
1398 
1399 	vmcore_off = elfcorebuf_sz + elfnotesz;
1400 
1401 	if (e_ident[EI_CLASS] == ELFCLASS64) {
1402 		Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfptr;
1403 		Elf64_Phdr *phdr = (Elf64_Phdr *)(elfptr + sizeof(Elf64_Ehdr));
1404 
1405 		/* Update all program headers */
1406 		for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1407 			if (phdr->p_type == PT_NOTE) {
1408 				/* Update note size */
1409 				phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1410 				phdr->p_filesz = phdr->p_memsz;
1411 				continue;
1412 			}
1413 
1414 			start = rounddown(phdr->p_offset, PAGE_SIZE);
1415 			end = roundup(phdr->p_offset + phdr->p_memsz,
1416 				      PAGE_SIZE);
1417 			size = end - start;
1418 			phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1419 			vmcore_off += size;
1420 		}
1421 	} else {
1422 		Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfptr;
1423 		Elf32_Phdr *phdr = (Elf32_Phdr *)(elfptr + sizeof(Elf32_Ehdr));
1424 
1425 		/* Update all program headers */
1426 		for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1427 			if (phdr->p_type == PT_NOTE) {
1428 				/* Update note size */
1429 				phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1430 				phdr->p_filesz = phdr->p_memsz;
1431 				continue;
1432 			}
1433 
1434 			start = rounddown(phdr->p_offset, PAGE_SIZE);
1435 			end = roundup(phdr->p_offset + phdr->p_memsz,
1436 				      PAGE_SIZE);
1437 			size = end - start;
1438 			phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1439 			vmcore_off += size;
1440 		}
1441 	}
1442 }
1443 
1444 /**
1445  * vmcoredd_update_size - Update the total size of the device dumps and update
1446  * ELF header
1447  * @dump_size: Size of the current device dump to be added to total size
1448  *
1449  * Update the total size of all the device dumps and update the ELF program
1450  * headers. Calculate the new offsets for the vmcore list and update the
1451  * total vmcore size.
1452  */
vmcoredd_update_size(size_t dump_size)1453 static void vmcoredd_update_size(size_t dump_size)
1454 {
1455 	vmcoredd_orig_sz += dump_size;
1456 	elfnotes_sz = roundup(elfnotes_orig_sz, PAGE_SIZE) + vmcoredd_orig_sz;
1457 	vmcoredd_update_program_headers(elfcorebuf, elfnotes_sz,
1458 					vmcoredd_orig_sz);
1459 
1460 	/* Update vmcore list offsets */
1461 	set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1462 
1463 	vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1464 				      &vmcore_list);
1465 	proc_vmcore->size = vmcore_size;
1466 }
1467 
1468 /**
1469  * vmcore_add_device_dump - Add a buffer containing device dump to vmcore
1470  * @data: dump info.
1471  *
1472  * Allocate a buffer and invoke the calling driver's dump collect routine.
1473  * Write ELF note at the beginning of the buffer to indicate vmcore device
1474  * dump and add the dump to global list.
1475  */
vmcore_add_device_dump(struct vmcoredd_data * data)1476 int vmcore_add_device_dump(struct vmcoredd_data *data)
1477 {
1478 	struct vmcoredd_node *dump;
1479 	void *buf = NULL;
1480 	size_t data_size;
1481 	int ret;
1482 
1483 	if (vmcoredd_disabled) {
1484 		pr_err_once("Device dump is disabled\n");
1485 		return -EINVAL;
1486 	}
1487 
1488 	if (!data || !strlen(data->dump_name) ||
1489 	    !data->vmcoredd_callback || !data->size)
1490 		return -EINVAL;
1491 
1492 	dump = vzalloc(sizeof(*dump));
1493 	if (!dump) {
1494 		ret = -ENOMEM;
1495 		goto out_err;
1496 	}
1497 
1498 	/* Keep size of the buffer page aligned so that it can be mmaped */
1499 	data_size = roundup(sizeof(struct vmcoredd_header) + data->size,
1500 			    PAGE_SIZE);
1501 
1502 	/* Allocate buffer for driver's to write their dumps */
1503 	buf = vmcore_alloc_buf(data_size);
1504 	if (!buf) {
1505 		ret = -ENOMEM;
1506 		goto out_err;
1507 	}
1508 
1509 	vmcoredd_write_header(buf, data, data_size -
1510 			      sizeof(struct vmcoredd_header));
1511 
1512 	/* Invoke the driver's dump collection routing */
1513 	ret = data->vmcoredd_callback(data, buf +
1514 				      sizeof(struct vmcoredd_header));
1515 	if (ret)
1516 		goto out_err;
1517 
1518 	dump->buf = buf;
1519 	dump->size = data_size;
1520 
1521 	/* Add the dump to driver sysfs list and update the elfcore hdr */
1522 	mutex_lock(&vmcore_mutex);
1523 	if (vmcore_opened)
1524 		pr_warn_once("Unexpected adding of device dump\n");
1525 	if (vmcore_open) {
1526 		ret = -EBUSY;
1527 		goto unlock;
1528 	}
1529 
1530 	list_add_tail(&dump->list, &vmcoredd_list);
1531 	vmcoredd_update_size(data_size);
1532 	mutex_unlock(&vmcore_mutex);
1533 	return 0;
1534 
1535 unlock:
1536 	mutex_unlock(&vmcore_mutex);
1537 
1538 out_err:
1539 	vfree(buf);
1540 	vfree(dump);
1541 
1542 	return ret;
1543 }
1544 EXPORT_SYMBOL(vmcore_add_device_dump);
1545 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1546 
1547 #ifdef CONFIG_PROC_VMCORE_DEVICE_RAM
vmcore_realloc_elfcore_buffer_elf64(size_t new_size)1548 static int vmcore_realloc_elfcore_buffer_elf64(size_t new_size)
1549 {
1550 	char *elfcorebuf_new;
1551 
1552 	if (WARN_ON_ONCE(new_size < elfcorebuf_sz))
1553 		return -EINVAL;
1554 	if (get_order(elfcorebuf_sz_orig) == get_order(new_size)) {
1555 		elfcorebuf_sz_orig = new_size;
1556 		return 0;
1557 	}
1558 
1559 	elfcorebuf_new = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1560 						  get_order(new_size));
1561 	if (!elfcorebuf_new)
1562 		return -ENOMEM;
1563 	memcpy(elfcorebuf_new, elfcorebuf, elfcorebuf_sz);
1564 	free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
1565 	elfcorebuf = elfcorebuf_new;
1566 	elfcorebuf_sz_orig = new_size;
1567 	return 0;
1568 }
1569 
vmcore_reset_offsets_elf64(void)1570 static void vmcore_reset_offsets_elf64(void)
1571 {
1572 	Elf64_Phdr *phdr_start = (Elf64_Phdr *)(elfcorebuf + sizeof(Elf64_Ehdr));
1573 	loff_t vmcore_off = elfcorebuf_sz + elfnotes_sz;
1574 	Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfcorebuf;
1575 	Elf64_Phdr *phdr;
1576 	int i;
1577 
1578 	for (i = 0, phdr = phdr_start; i < ehdr->e_phnum; i++, phdr++) {
1579 		u64 start, end;
1580 
1581 		/*
1582 		 * After merge_note_headers_elf64() we should only have a single
1583 		 * PT_NOTE entry that starts immediately after elfcorebuf_sz.
1584 		 */
1585 		if (phdr->p_type == PT_NOTE) {
1586 			phdr->p_offset = elfcorebuf_sz;
1587 			continue;
1588 		}
1589 
1590 		start = rounddown(phdr->p_offset, PAGE_SIZE);
1591 		end = roundup(phdr->p_offset + phdr->p_memsz, PAGE_SIZE);
1592 		phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1593 		vmcore_off = vmcore_off + end - start;
1594 	}
1595 	set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1596 }
1597 
vmcore_add_device_ram_elf64(struct list_head * list,size_t count)1598 static int vmcore_add_device_ram_elf64(struct list_head *list, size_t count)
1599 {
1600 	Elf64_Phdr *phdr_start = (Elf64_Phdr *)(elfcorebuf + sizeof(Elf64_Ehdr));
1601 	Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfcorebuf;
1602 	struct vmcore_range *cur;
1603 	Elf64_Phdr *phdr;
1604 	size_t new_size;
1605 	int rc;
1606 
1607 	if ((Elf32_Half)(ehdr->e_phnum + count) != ehdr->e_phnum + count) {
1608 		pr_err("too many device ram ranges\n");
1609 		return -ENOSPC;
1610 	}
1611 
1612 	/* elfcorebuf_sz must always cover full pages. */
1613 	new_size = sizeof(Elf64_Ehdr) +
1614 		   (ehdr->e_phnum + count) * sizeof(Elf64_Phdr);
1615 	new_size = roundup(new_size, PAGE_SIZE);
1616 
1617 	/*
1618 	 * Make sure we have sufficient space to include the new PT_LOAD
1619 	 * entries.
1620 	 */
1621 	rc = vmcore_realloc_elfcore_buffer_elf64(new_size);
1622 	if (rc) {
1623 		pr_err("resizing elfcore failed\n");
1624 		return rc;
1625 	}
1626 
1627 	/* Modify our used elfcore buffer size to cover the new entries. */
1628 	elfcorebuf_sz = new_size;
1629 
1630 	/* Fill the added PT_LOAD entries. */
1631 	phdr = phdr_start + ehdr->e_phnum;
1632 	list_for_each_entry(cur, list, list) {
1633 		WARN_ON_ONCE(!IS_ALIGNED(cur->paddr | cur->size, PAGE_SIZE));
1634 		elfcorehdr_fill_device_ram_ptload_elf64(phdr, cur->paddr, cur->size);
1635 
1636 		/* p_offset will be adjusted later. */
1637 		phdr++;
1638 		ehdr->e_phnum++;
1639 	}
1640 	list_splice_tail(list, &vmcore_list);
1641 
1642 	/* We changed elfcorebuf_sz and added new entries; reset all offsets. */
1643 	vmcore_reset_offsets_elf64();
1644 
1645 	/* Finally, recalculate the total vmcore size. */
1646 	vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1647 				      &vmcore_list);
1648 	proc_vmcore->size = vmcore_size;
1649 	return 0;
1650 }
1651 
vmcore_process_device_ram(struct vmcore_cb * cb)1652 static void vmcore_process_device_ram(struct vmcore_cb *cb)
1653 {
1654 	unsigned char *e_ident = (unsigned char *)elfcorebuf;
1655 	struct vmcore_range *first, *m;
1656 	LIST_HEAD(list);
1657 	int count;
1658 
1659 	/* We only support Elf64 dumps for now. */
1660 	if (WARN_ON_ONCE(e_ident[EI_CLASS] != ELFCLASS64)) {
1661 		pr_err("device ram ranges only support Elf64\n");
1662 		return;
1663 	}
1664 
1665 	if (cb->get_device_ram(cb, &list)) {
1666 		pr_err("obtaining device ram ranges failed\n");
1667 		return;
1668 	}
1669 	count = list_count_nodes(&list);
1670 	if (!count)
1671 		return;
1672 
1673 	/*
1674 	 * For some reason these ranges are already know? Might happen
1675 	 * with unusual register->unregister->register sequences; we'll simply
1676 	 * sanity check using the first range.
1677 	 */
1678 	first = list_first_entry(&list, struct vmcore_range, list);
1679 	list_for_each_entry(m, &vmcore_list, list) {
1680 		unsigned long long m_end = m->paddr + m->size;
1681 		unsigned long long first_end = first->paddr + first->size;
1682 
1683 		if (first->paddr < m_end && m->paddr < first_end)
1684 			goto out_free;
1685 	}
1686 
1687 	/* If adding the mem nodes succeeds, they must not be freed. */
1688 	if (!vmcore_add_device_ram_elf64(&list, count))
1689 		return;
1690 out_free:
1691 	vmcore_free_ranges(&list);
1692 }
1693 #else /* !CONFIG_PROC_VMCORE_DEVICE_RAM */
vmcore_process_device_ram(struct vmcore_cb * cb)1694 static void vmcore_process_device_ram(struct vmcore_cb *cb)
1695 {
1696 }
1697 #endif /* CONFIG_PROC_VMCORE_DEVICE_RAM */
1698 
1699 /* Free all dumps in vmcore device dump list */
vmcore_free_device_dumps(void)1700 static void vmcore_free_device_dumps(void)
1701 {
1702 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1703 	mutex_lock(&vmcore_mutex);
1704 	while (!list_empty(&vmcoredd_list)) {
1705 		struct vmcoredd_node *dump;
1706 
1707 		dump = list_first_entry(&vmcoredd_list, struct vmcoredd_node,
1708 					list);
1709 		list_del(&dump->list);
1710 		vfree(dump->buf);
1711 		vfree(dump);
1712 	}
1713 	mutex_unlock(&vmcore_mutex);
1714 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1715 }
1716 
1717 /* Init function for vmcore module. */
vmcore_init(void)1718 static int __init vmcore_init(void)
1719 {
1720 	int rc = 0;
1721 
1722 	/* Allow architectures to allocate ELF header in 2nd kernel */
1723 	rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1724 	if (rc)
1725 		return rc;
1726 	/*
1727 	 * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1728 	 * then capture the dump.
1729 	 */
1730 	if (!(is_vmcore_usable()))
1731 		return rc;
1732 	rc = parse_crash_elf_headers();
1733 	if (rc) {
1734 		elfcorehdr_free(elfcorehdr_addr);
1735 		pr_warn("not initialized\n");
1736 		return rc;
1737 	}
1738 	elfcorehdr_free(elfcorehdr_addr);
1739 	elfcorehdr_addr = ELFCORE_ADDR_ERR;
1740 
1741 	proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &vmcore_proc_ops);
1742 	if (proc_vmcore)
1743 		proc_vmcore->size = vmcore_size;
1744 	return 0;
1745 }
1746 fs_initcall(vmcore_init);
1747 
1748 /* Cleanup function for vmcore module. */
vmcore_cleanup(void)1749 void vmcore_cleanup(void)
1750 {
1751 	if (proc_vmcore) {
1752 		proc_remove(proc_vmcore);
1753 		proc_vmcore = NULL;
1754 	}
1755 
1756 	vmcore_free_ranges(&vmcore_list);
1757 	free_elfcorebuf();
1758 
1759 	/* clear vmcore device dump list */
1760 	vmcore_free_device_dumps();
1761 }
1762