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