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