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