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1/*
2 * fs/proc/vmcore.c Interface for accessing the crash
3 * dump from the system's previous life.
4 * Heavily borrowed from fs/proc/kcore.c
5 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
6 * Copyright (C) IBM Corporation, 2004. All rights reserved
7 *
8 */
9
10#include <linux/mm.h>
11#include <linux/kcore.h>
12#include <linux/user.h>
13#include <linux/elf.h>
14#include <linux/elfcore.h>
15#include <linux/export.h>
16#include <linux/slab.h>
17#include <linux/highmem.h>
18#include <linux/printk.h>
19#include <linux/bootmem.h>
20#include <linux/init.h>
21#include <linux/crash_dump.h>
22#include <linux/list.h>
23#include <linux/vmalloc.h>
24#include <linux/pagemap.h>
25#include <asm/uaccess.h>
26#include <asm/io.h>
27#include "internal.h"
28
29/* List representing chunks of contiguous memory areas and their offsets in
30 * vmcore file.
31 */
32static LIST_HEAD(vmcore_list);
33
34/* Stores the pointer to the buffer containing kernel elf core headers. */
35static char *elfcorebuf;
36static size_t elfcorebuf_sz;
37static size_t elfcorebuf_sz_orig;
38
39static char *elfnotes_buf;
40static size_t elfnotes_sz;
41
42/* Total size of vmcore file. */
43static u64 vmcore_size;
44
45static struct proc_dir_entry *proc_vmcore;
46
47/*
48 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
49 * The called function has to take care of module refcounting.
50 */
51static int (*oldmem_pfn_is_ram)(unsigned long pfn);
52
53int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
54{
55 if (oldmem_pfn_is_ram)
56 return -EBUSY;
57 oldmem_pfn_is_ram = fn;
58 return 0;
59}
60EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
61
62void unregister_oldmem_pfn_is_ram(void)
63{
64 oldmem_pfn_is_ram = NULL;
65 wmb();
66}
67EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
68
69static int pfn_is_ram(unsigned long pfn)
70{
71 int (*fn)(unsigned long pfn);
72 /* pfn is ram unless fn() checks pagetype */
73 int ret = 1;
74
75 /*
76 * Ask hypervisor if the pfn is really ram.
77 * A ballooned page contains no data and reading from such a page
78 * will cause high load in the hypervisor.
79 */
80 fn = oldmem_pfn_is_ram;
81 if (fn)
82 ret = fn(pfn);
83
84 return ret;
85}
86
87/* Reads a page from the oldmem device from given offset. */
88static ssize_t read_from_oldmem(char *buf, size_t count,
89 u64 *ppos, int userbuf)
90{
91 unsigned long pfn, offset;
92 size_t nr_bytes;
93 ssize_t read = 0, tmp;
94
95 if (!count)
96 return 0;
97
98 offset = (unsigned long)(*ppos % PAGE_SIZE);
99 pfn = (unsigned long)(*ppos / PAGE_SIZE);
100
101 do {
102 if (count > (PAGE_SIZE - offset))
103 nr_bytes = PAGE_SIZE - offset;
104 else
105 nr_bytes = count;
106
107 /* If pfn is not ram, return zeros for sparse dump files */
108 if (pfn_is_ram(pfn) == 0)
109 memset(buf, 0, nr_bytes);
110 else {
111 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
112 offset, userbuf);
113 if (tmp < 0)
114 return tmp;
115 }
116 *ppos += nr_bytes;
117 count -= nr_bytes;
118 buf += nr_bytes;
119 read += nr_bytes;
120 ++pfn;
121 offset = 0;
122 } while (count);
123
124 return read;
125}
126
127/*
128 * Architectures may override this function to allocate ELF header in 2nd kernel
129 */
130int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
131{
132 return 0;
133}
134
135/*
136 * Architectures may override this function to free header
137 */
138void __weak elfcorehdr_free(unsigned long long addr)
139{}
140
141/*
142 * Architectures may override this function to read from ELF header
143 */
144ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
145{
146 return read_from_oldmem(buf, count, ppos, 0);
147}
148
149/*
150 * Architectures may override this function to read from notes sections
151 */
152ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
153{
154 return read_from_oldmem(buf, count, ppos, 0);
155}
156
157/*
158 * Architectures may override this function to map oldmem
159 */
160int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
161 unsigned long from, unsigned long pfn,
162 unsigned long size, pgprot_t prot)
163{
164 return remap_pfn_range(vma, from, pfn, size, prot);
165}
166
167/*
168 * Copy to either kernel or user space
169 */
170static int copy_to(void *target, void *src, size_t size, int userbuf)
171{
172 if (userbuf) {
173 if (copy_to_user((char __user *) target, src, size))
174 return -EFAULT;
175 } else {
176 memcpy(target, src, size);
177 }
178 return 0;
179}
180
181/* Read from the ELF header and then the crash dump. On error, negative value is
182 * returned otherwise number of bytes read are returned.
183 */
184static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
185 int userbuf)
186{
187 ssize_t acc = 0, tmp;
188 size_t tsz;
189 u64 start;
190 struct vmcore *m = NULL;
191
192 if (buflen == 0 || *fpos >= vmcore_size)
193 return 0;
194
195 /* trim buflen to not go beyond EOF */
196 if (buflen > vmcore_size - *fpos)
197 buflen = vmcore_size - *fpos;
198
199 /* Read ELF core header */
200 if (*fpos < elfcorebuf_sz) {
201 tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
202 if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
203 return -EFAULT;
204 buflen -= tsz;
205 *fpos += tsz;
206 buffer += tsz;
207 acc += tsz;
208
209 /* leave now if filled buffer already */
210 if (buflen == 0)
211 return acc;
212 }
213
214 /* Read Elf note segment */
215 if (*fpos < elfcorebuf_sz + elfnotes_sz) {
216 void *kaddr;
217
218 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
219 kaddr = elfnotes_buf + *fpos - elfcorebuf_sz;
220 if (copy_to(buffer, kaddr, tsz, userbuf))
221 return -EFAULT;
222 buflen -= tsz;
223 *fpos += tsz;
224 buffer += tsz;
225 acc += tsz;
226
227 /* leave now if filled buffer already */
228 if (buflen == 0)
229 return acc;
230 }
231
232 list_for_each_entry(m, &vmcore_list, list) {
233 if (*fpos < m->offset + m->size) {
234 tsz = (size_t)min_t(unsigned long long,
235 m->offset + m->size - *fpos,
236 buflen);
237 start = m->paddr + *fpos - m->offset;
238 tmp = read_from_oldmem(buffer, tsz, &start, userbuf);
239 if (tmp < 0)
240 return tmp;
241 buflen -= tsz;
242 *fpos += tsz;
243 buffer += tsz;
244 acc += tsz;
245
246 /* leave now if filled buffer already */
247 if (buflen == 0)
248 return acc;
249 }
250 }
251
252 return acc;
253}
254
255static ssize_t read_vmcore(struct file *file, char __user *buffer,
256 size_t buflen, loff_t *fpos)
257{
258 return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
259}
260
261/*
262 * The vmcore fault handler uses the page cache and fills data using the
263 * standard __vmcore_read() function.
264 *
265 * On s390 the fault handler is used for memory regions that can't be mapped
266 * directly with remap_pfn_range().
267 */
268static int mmap_vmcore_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
269{
270#ifdef CONFIG_S390
271 struct address_space *mapping = vma->vm_file->f_mapping;
272 pgoff_t index = vmf->pgoff;
273 struct page *page;
274 loff_t offset;
275 char *buf;
276 int rc;
277
278 page = find_or_create_page(mapping, index, GFP_KERNEL);
279 if (!page)
280 return VM_FAULT_OOM;
281 if (!PageUptodate(page)) {
282 offset = (loff_t) index << PAGE_SHIFT;
283 buf = __va((page_to_pfn(page) << PAGE_SHIFT));
284 rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
285 if (rc < 0) {
286 unlock_page(page);
287 put_page(page);
288 return (rc == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
289 }
290 SetPageUptodate(page);
291 }
292 unlock_page(page);
293 vmf->page = page;
294 return 0;
295#else
296 return VM_FAULT_SIGBUS;
297#endif
298}
299
300static const struct vm_operations_struct vmcore_mmap_ops = {
301 .fault = mmap_vmcore_fault,
302};
303
304/**
305 * alloc_elfnotes_buf - allocate buffer for ELF note segment in
306 * vmalloc memory
307 *
308 * @notes_sz: size of buffer
309 *
310 * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
311 * the buffer to user-space by means of remap_vmalloc_range().
312 *
313 * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
314 * disabled and there's no need to allow users to mmap the buffer.
315 */
316static inline char *alloc_elfnotes_buf(size_t notes_sz)
317{
318#ifdef CONFIG_MMU
319 return vmalloc_user(notes_sz);
320#else
321 return vzalloc(notes_sz);
322#endif
323}
324
325/*
326 * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
327 * essential for mmap_vmcore() in order to map physically
328 * non-contiguous objects (ELF header, ELF note segment and memory
329 * regions in the 1st kernel pointed to by PT_LOAD entries) into
330 * virtually contiguous user-space in ELF layout.
331 */
332#ifdef CONFIG_MMU
333/*
334 * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
335 * reported as not being ram with the zero page.
336 *
337 * @vma: vm_area_struct describing requested mapping
338 * @from: start remapping from
339 * @pfn: page frame number to start remapping to
340 * @size: remapping size
341 * @prot: protection bits
342 *
343 * Returns zero on success, -EAGAIN on failure.
344 */
345static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
346 unsigned long from, unsigned long pfn,
347 unsigned long size, pgprot_t prot)
348{
349 unsigned long map_size;
350 unsigned long pos_start, pos_end, pos;
351 unsigned long zeropage_pfn = my_zero_pfn(0);
352 size_t len = 0;
353
354 pos_start = pfn;
355 pos_end = pfn + (size >> PAGE_SHIFT);
356
357 for (pos = pos_start; pos < pos_end; ++pos) {
358 if (!pfn_is_ram(pos)) {
359 /*
360 * We hit a page which is not ram. Remap the continuous
361 * region between pos_start and pos-1 and replace
362 * the non-ram page at pos with the zero page.
363 */
364 if (pos > pos_start) {
365 /* Remap continuous region */
366 map_size = (pos - pos_start) << PAGE_SHIFT;
367 if (remap_oldmem_pfn_range(vma, from + len,
368 pos_start, map_size,
369 prot))
370 goto fail;
371 len += map_size;
372 }
373 /* Remap the zero page */
374 if (remap_oldmem_pfn_range(vma, from + len,
375 zeropage_pfn,
376 PAGE_SIZE, prot))
377 goto fail;
378 len += PAGE_SIZE;
379 pos_start = pos + 1;
380 }
381 }
382 if (pos > pos_start) {
383 /* Remap the rest */
384 map_size = (pos - pos_start) << PAGE_SHIFT;
385 if (remap_oldmem_pfn_range(vma, from + len, pos_start,
386 map_size, prot))
387 goto fail;
388 }
389 return 0;
390fail:
391 do_munmap(vma->vm_mm, from, len);
392 return -EAGAIN;
393}
394
395static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
396 unsigned long from, unsigned long pfn,
397 unsigned long size, pgprot_t prot)
398{
399 /*
400 * Check if oldmem_pfn_is_ram was registered to avoid
401 * looping over all pages without a reason.
402 */
403 if (oldmem_pfn_is_ram)
404 return remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
405 else
406 return remap_oldmem_pfn_range(vma, from, pfn, size, prot);
407}
408
409static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
410{
411 size_t size = vma->vm_end - vma->vm_start;
412 u64 start, end, len, tsz;
413 struct vmcore *m;
414
415 start = (u64)vma->vm_pgoff << PAGE_SHIFT;
416 end = start + size;
417
418 if (size > vmcore_size || end > vmcore_size)
419 return -EINVAL;
420
421 if (vma->vm_flags & (VM_WRITE | VM_EXEC))
422 return -EPERM;
423
424 vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
425 vma->vm_flags |= VM_MIXEDMAP;
426 vma->vm_ops = &vmcore_mmap_ops;
427
428 len = 0;
429
430 if (start < elfcorebuf_sz) {
431 u64 pfn;
432
433 tsz = min(elfcorebuf_sz - (size_t)start, size);
434 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
435 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
436 vma->vm_page_prot))
437 return -EAGAIN;
438 size -= tsz;
439 start += tsz;
440 len += tsz;
441
442 if (size == 0)
443 return 0;
444 }
445
446 if (start < elfcorebuf_sz + elfnotes_sz) {
447 void *kaddr;
448
449 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
450 kaddr = elfnotes_buf + start - elfcorebuf_sz;
451 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
452 kaddr, tsz))
453 goto fail;
454 size -= tsz;
455 start += tsz;
456 len += tsz;
457
458 if (size == 0)
459 return 0;
460 }
461
462 list_for_each_entry(m, &vmcore_list, list) {
463 if (start < m->offset + m->size) {
464 u64 paddr = 0;
465
466 tsz = (size_t)min_t(unsigned long long,
467 m->offset + m->size - start, size);
468 paddr = m->paddr + start - m->offset;
469 if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
470 paddr >> PAGE_SHIFT, tsz,
471 vma->vm_page_prot))
472 goto fail;
473 size -= tsz;
474 start += tsz;
475 len += tsz;
476
477 if (size == 0)
478 return 0;
479 }
480 }
481
482 return 0;
483fail:
484 do_munmap(vma->vm_mm, vma->vm_start, len);
485 return -EAGAIN;
486}
487#else
488static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
489{
490 return -ENOSYS;
491}
492#endif
493
494static const struct file_operations proc_vmcore_operations = {
495 .read = read_vmcore,
496 .llseek = default_llseek,
497 .mmap = mmap_vmcore,
498};
499
500static struct vmcore* __init get_new_element(void)
501{
502 return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
503}
504
505static u64 __init get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
506 struct list_head *vc_list)
507{
508 u64 size;
509 struct vmcore *m;
510
511 size = elfsz + elfnotesegsz;
512 list_for_each_entry(m, vc_list, list) {
513 size += m->size;
514 }
515 return size;
516}
517
518/**
519 * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
520 *
521 * @ehdr_ptr: ELF header
522 *
523 * This function updates p_memsz member of each PT_NOTE entry in the
524 * program header table pointed to by @ehdr_ptr to real size of ELF
525 * note segment.
526 */
527static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
528{
529 int i, rc=0;
530 Elf64_Phdr *phdr_ptr;
531 Elf64_Nhdr *nhdr_ptr;
532
533 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
534 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
535 void *notes_section;
536 u64 offset, max_sz, sz, real_sz = 0;
537 if (phdr_ptr->p_type != PT_NOTE)
538 continue;
539 max_sz = phdr_ptr->p_memsz;
540 offset = phdr_ptr->p_offset;
541 notes_section = kmalloc(max_sz, GFP_KERNEL);
542 if (!notes_section)
543 return -ENOMEM;
544 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
545 if (rc < 0) {
546 kfree(notes_section);
547 return rc;
548 }
549 nhdr_ptr = notes_section;
550 while (nhdr_ptr->n_namesz != 0) {
551 sz = sizeof(Elf64_Nhdr) +
552 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
553 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
554 if ((real_sz + sz) > max_sz) {
555 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
556 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
557 break;
558 }
559 real_sz += sz;
560 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
561 }
562 kfree(notes_section);
563 phdr_ptr->p_memsz = real_sz;
564 if (real_sz == 0) {
565 pr_warn("Warning: Zero PT_NOTE entries found\n");
566 }
567 }
568
569 return 0;
570}
571
572/**
573 * get_note_number_and_size_elf64 - get the number of PT_NOTE program
574 * headers and sum of real size of their ELF note segment headers and
575 * data.
576 *
577 * @ehdr_ptr: ELF header
578 * @nr_ptnote: buffer for the number of PT_NOTE program headers
579 * @sz_ptnote: buffer for size of unique PT_NOTE program header
580 *
581 * This function is used to merge multiple PT_NOTE program headers
582 * into a unique single one. The resulting unique entry will have
583 * @sz_ptnote in its phdr->p_mem.
584 *
585 * It is assumed that program headers with PT_NOTE type pointed to by
586 * @ehdr_ptr has already been updated by update_note_header_size_elf64
587 * and each of PT_NOTE program headers has actual ELF note segment
588 * size in its p_memsz member.
589 */
590static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
591 int *nr_ptnote, u64 *sz_ptnote)
592{
593 int i;
594 Elf64_Phdr *phdr_ptr;
595
596 *nr_ptnote = *sz_ptnote = 0;
597
598 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
599 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
600 if (phdr_ptr->p_type != PT_NOTE)
601 continue;
602 *nr_ptnote += 1;
603 *sz_ptnote += phdr_ptr->p_memsz;
604 }
605
606 return 0;
607}
608
609/**
610 * copy_notes_elf64 - copy ELF note segments in a given buffer
611 *
612 * @ehdr_ptr: ELF header
613 * @notes_buf: buffer into which ELF note segments are copied
614 *
615 * This function is used to copy ELF note segment in the 1st kernel
616 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
617 * size of the buffer @notes_buf is equal to or larger than sum of the
618 * real ELF note segment headers and data.
619 *
620 * It is assumed that program headers with PT_NOTE type pointed to by
621 * @ehdr_ptr has already been updated by update_note_header_size_elf64
622 * and each of PT_NOTE program headers has actual ELF note segment
623 * size in its p_memsz member.
624 */
625static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
626{
627 int i, rc=0;
628 Elf64_Phdr *phdr_ptr;
629
630 phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
631
632 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
633 u64 offset;
634 if (phdr_ptr->p_type != PT_NOTE)
635 continue;
636 offset = phdr_ptr->p_offset;
637 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
638 &offset);
639 if (rc < 0)
640 return rc;
641 notes_buf += phdr_ptr->p_memsz;
642 }
643
644 return 0;
645}
646
647/* Merges all the PT_NOTE headers into one. */
648static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
649 char **notes_buf, size_t *notes_sz)
650{
651 int i, nr_ptnote=0, rc=0;
652 char *tmp;
653 Elf64_Ehdr *ehdr_ptr;
654 Elf64_Phdr phdr;
655 u64 phdr_sz = 0, note_off;
656
657 ehdr_ptr = (Elf64_Ehdr *)elfptr;
658
659 rc = update_note_header_size_elf64(ehdr_ptr);
660 if (rc < 0)
661 return rc;
662
663 rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
664 if (rc < 0)
665 return rc;
666
667 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
668 *notes_buf = alloc_elfnotes_buf(*notes_sz);
669 if (!*notes_buf)
670 return -ENOMEM;
671
672 rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
673 if (rc < 0)
674 return rc;
675
676 /* Prepare merged PT_NOTE program header. */
677 phdr.p_type = PT_NOTE;
678 phdr.p_flags = 0;
679 note_off = sizeof(Elf64_Ehdr) +
680 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
681 phdr.p_offset = roundup(note_off, PAGE_SIZE);
682 phdr.p_vaddr = phdr.p_paddr = 0;
683 phdr.p_filesz = phdr.p_memsz = phdr_sz;
684 phdr.p_align = 0;
685
686 /* Add merged PT_NOTE program header*/
687 tmp = elfptr + sizeof(Elf64_Ehdr);
688 memcpy(tmp, &phdr, sizeof(phdr));
689 tmp += sizeof(phdr);
690
691 /* Remove unwanted PT_NOTE program headers. */
692 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
693 *elfsz = *elfsz - i;
694 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
695 memset(elfptr + *elfsz, 0, i);
696 *elfsz = roundup(*elfsz, PAGE_SIZE);
697
698 /* Modify e_phnum to reflect merged headers. */
699 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
700
701 return 0;
702}
703
704/**
705 * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
706 *
707 * @ehdr_ptr: ELF header
708 *
709 * This function updates p_memsz member of each PT_NOTE entry in the
710 * program header table pointed to by @ehdr_ptr to real size of ELF
711 * note segment.
712 */
713static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
714{
715 int i, rc=0;
716 Elf32_Phdr *phdr_ptr;
717 Elf32_Nhdr *nhdr_ptr;
718
719 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
720 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
721 void *notes_section;
722 u64 offset, max_sz, sz, real_sz = 0;
723 if (phdr_ptr->p_type != PT_NOTE)
724 continue;
725 max_sz = phdr_ptr->p_memsz;
726 offset = phdr_ptr->p_offset;
727 notes_section = kmalloc(max_sz, GFP_KERNEL);
728 if (!notes_section)
729 return -ENOMEM;
730 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
731 if (rc < 0) {
732 kfree(notes_section);
733 return rc;
734 }
735 nhdr_ptr = notes_section;
736 while (nhdr_ptr->n_namesz != 0) {
737 sz = sizeof(Elf32_Nhdr) +
738 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
739 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
740 if ((real_sz + sz) > max_sz) {
741 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
742 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
743 break;
744 }
745 real_sz += sz;
746 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
747 }
748 kfree(notes_section);
749 phdr_ptr->p_memsz = real_sz;
750 if (real_sz == 0) {
751 pr_warn("Warning: Zero PT_NOTE entries found\n");
752 }
753 }
754
755 return 0;
756}
757
758/**
759 * get_note_number_and_size_elf32 - get the number of PT_NOTE program
760 * headers and sum of real size of their ELF note segment headers and
761 * data.
762 *
763 * @ehdr_ptr: ELF header
764 * @nr_ptnote: buffer for the number of PT_NOTE program headers
765 * @sz_ptnote: buffer for size of unique PT_NOTE program header
766 *
767 * This function is used to merge multiple PT_NOTE program headers
768 * into a unique single one. The resulting unique entry will have
769 * @sz_ptnote in its phdr->p_mem.
770 *
771 * It is assumed that program headers with PT_NOTE type pointed to by
772 * @ehdr_ptr has already been updated by update_note_header_size_elf32
773 * and each of PT_NOTE program headers has actual ELF note segment
774 * size in its p_memsz member.
775 */
776static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
777 int *nr_ptnote, u64 *sz_ptnote)
778{
779 int i;
780 Elf32_Phdr *phdr_ptr;
781
782 *nr_ptnote = *sz_ptnote = 0;
783
784 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
785 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
786 if (phdr_ptr->p_type != PT_NOTE)
787 continue;
788 *nr_ptnote += 1;
789 *sz_ptnote += phdr_ptr->p_memsz;
790 }
791
792 return 0;
793}
794
795/**
796 * copy_notes_elf32 - copy ELF note segments in a given buffer
797 *
798 * @ehdr_ptr: ELF header
799 * @notes_buf: buffer into which ELF note segments are copied
800 *
801 * This function is used to copy ELF note segment in the 1st kernel
802 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
803 * size of the buffer @notes_buf is equal to or larger than sum of the
804 * real ELF note segment headers and data.
805 *
806 * It is assumed that program headers with PT_NOTE type pointed to by
807 * @ehdr_ptr has already been updated by update_note_header_size_elf32
808 * and each of PT_NOTE program headers has actual ELF note segment
809 * size in its p_memsz member.
810 */
811static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
812{
813 int i, rc=0;
814 Elf32_Phdr *phdr_ptr;
815
816 phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
817
818 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
819 u64 offset;
820 if (phdr_ptr->p_type != PT_NOTE)
821 continue;
822 offset = phdr_ptr->p_offset;
823 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
824 &offset);
825 if (rc < 0)
826 return rc;
827 notes_buf += phdr_ptr->p_memsz;
828 }
829
830 return 0;
831}
832
833/* Merges all the PT_NOTE headers into one. */
834static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
835 char **notes_buf, size_t *notes_sz)
836{
837 int i, nr_ptnote=0, rc=0;
838 char *tmp;
839 Elf32_Ehdr *ehdr_ptr;
840 Elf32_Phdr phdr;
841 u64 phdr_sz = 0, note_off;
842
843 ehdr_ptr = (Elf32_Ehdr *)elfptr;
844
845 rc = update_note_header_size_elf32(ehdr_ptr);
846 if (rc < 0)
847 return rc;
848
849 rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
850 if (rc < 0)
851 return rc;
852
853 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
854 *notes_buf = alloc_elfnotes_buf(*notes_sz);
855 if (!*notes_buf)
856 return -ENOMEM;
857
858 rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
859 if (rc < 0)
860 return rc;
861
862 /* Prepare merged PT_NOTE program header. */
863 phdr.p_type = PT_NOTE;
864 phdr.p_flags = 0;
865 note_off = sizeof(Elf32_Ehdr) +
866 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
867 phdr.p_offset = roundup(note_off, PAGE_SIZE);
868 phdr.p_vaddr = phdr.p_paddr = 0;
869 phdr.p_filesz = phdr.p_memsz = phdr_sz;
870 phdr.p_align = 0;
871
872 /* Add merged PT_NOTE program header*/
873 tmp = elfptr + sizeof(Elf32_Ehdr);
874 memcpy(tmp, &phdr, sizeof(phdr));
875 tmp += sizeof(phdr);
876
877 /* Remove unwanted PT_NOTE program headers. */
878 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
879 *elfsz = *elfsz - i;
880 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
881 memset(elfptr + *elfsz, 0, i);
882 *elfsz = roundup(*elfsz, PAGE_SIZE);
883
884 /* Modify e_phnum to reflect merged headers. */
885 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
886
887 return 0;
888}
889
890/* Add memory chunks represented by program headers to vmcore list. Also update
891 * the new offset fields of exported program headers. */
892static int __init process_ptload_program_headers_elf64(char *elfptr,
893 size_t elfsz,
894 size_t elfnotes_sz,
895 struct list_head *vc_list)
896{
897 int i;
898 Elf64_Ehdr *ehdr_ptr;
899 Elf64_Phdr *phdr_ptr;
900 loff_t vmcore_off;
901 struct vmcore *new;
902
903 ehdr_ptr = (Elf64_Ehdr *)elfptr;
904 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
905
906 /* Skip Elf header, program headers and Elf note segment. */
907 vmcore_off = elfsz + elfnotes_sz;
908
909 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
910 u64 paddr, start, end, size;
911
912 if (phdr_ptr->p_type != PT_LOAD)
913 continue;
914
915 paddr = phdr_ptr->p_offset;
916 start = rounddown(paddr, PAGE_SIZE);
917 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
918 size = end - start;
919
920 /* Add this contiguous chunk of memory to vmcore list.*/
921 new = get_new_element();
922 if (!new)
923 return -ENOMEM;
924 new->paddr = start;
925 new->size = size;
926 list_add_tail(&new->list, vc_list);
927
928 /* Update the program header offset. */
929 phdr_ptr->p_offset = vmcore_off + (paddr - start);
930 vmcore_off = vmcore_off + size;
931 }
932 return 0;
933}
934
935static int __init process_ptload_program_headers_elf32(char *elfptr,
936 size_t elfsz,
937 size_t elfnotes_sz,
938 struct list_head *vc_list)
939{
940 int i;
941 Elf32_Ehdr *ehdr_ptr;
942 Elf32_Phdr *phdr_ptr;
943 loff_t vmcore_off;
944 struct vmcore *new;
945
946 ehdr_ptr = (Elf32_Ehdr *)elfptr;
947 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
948
949 /* Skip Elf header, program headers and Elf note segment. */
950 vmcore_off = elfsz + elfnotes_sz;
951
952 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
953 u64 paddr, start, end, size;
954
955 if (phdr_ptr->p_type != PT_LOAD)
956 continue;
957
958 paddr = phdr_ptr->p_offset;
959 start = rounddown(paddr, PAGE_SIZE);
960 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
961 size = end - start;
962
963 /* Add this contiguous chunk of memory to vmcore list.*/
964 new = get_new_element();
965 if (!new)
966 return -ENOMEM;
967 new->paddr = start;
968 new->size = size;
969 list_add_tail(&new->list, vc_list);
970
971 /* Update the program header offset */
972 phdr_ptr->p_offset = vmcore_off + (paddr - start);
973 vmcore_off = vmcore_off + size;
974 }
975 return 0;
976}
977
978/* Sets offset fields of vmcore elements. */
979static void __init set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
980 struct list_head *vc_list)
981{
982 loff_t vmcore_off;
983 struct vmcore *m;
984
985 /* Skip Elf header, program headers and Elf note segment. */
986 vmcore_off = elfsz + elfnotes_sz;
987
988 list_for_each_entry(m, vc_list, list) {
989 m->offset = vmcore_off;
990 vmcore_off += m->size;
991 }
992}
993
994static void free_elfcorebuf(void)
995{
996 free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
997 elfcorebuf = NULL;
998 vfree(elfnotes_buf);
999 elfnotes_buf = NULL;
1000}
1001
1002static int __init parse_crash_elf64_headers(void)
1003{
1004 int rc=0;
1005 Elf64_Ehdr ehdr;
1006 u64 addr;
1007
1008 addr = elfcorehdr_addr;
1009
1010 /* Read Elf header */
1011 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
1012 if (rc < 0)
1013 return rc;
1014
1015 /* Do some basic Verification. */
1016 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1017 (ehdr.e_type != ET_CORE) ||
1018 !vmcore_elf64_check_arch(&ehdr) ||
1019 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
1020 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1021 ehdr.e_version != EV_CURRENT ||
1022 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
1023 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
1024 ehdr.e_phnum == 0) {
1025 pr_warn("Warning: Core image elf header is not sane\n");
1026 return -EINVAL;
1027 }
1028
1029 /* Read in all elf headers. */
1030 elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
1031 ehdr.e_phnum * sizeof(Elf64_Phdr);
1032 elfcorebuf_sz = elfcorebuf_sz_orig;
1033 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1034 get_order(elfcorebuf_sz_orig));
1035 if (!elfcorebuf)
1036 return -ENOMEM;
1037 addr = elfcorehdr_addr;
1038 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1039 if (rc < 0)
1040 goto fail;
1041
1042 /* Merge all PT_NOTE headers into one. */
1043 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
1044 &elfnotes_buf, &elfnotes_sz);
1045 if (rc)
1046 goto fail;
1047 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
1048 elfnotes_sz, &vmcore_list);
1049 if (rc)
1050 goto fail;
1051 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1052 return 0;
1053fail:
1054 free_elfcorebuf();
1055 return rc;
1056}
1057
1058static int __init parse_crash_elf32_headers(void)
1059{
1060 int rc=0;
1061 Elf32_Ehdr ehdr;
1062 u64 addr;
1063
1064 addr = elfcorehdr_addr;
1065
1066 /* Read Elf header */
1067 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
1068 if (rc < 0)
1069 return rc;
1070
1071 /* Do some basic Verification. */
1072 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1073 (ehdr.e_type != ET_CORE) ||
1074 !elf_check_arch(&ehdr) ||
1075 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
1076 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1077 ehdr.e_version != EV_CURRENT ||
1078 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1079 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1080 ehdr.e_phnum == 0) {
1081 pr_warn("Warning: Core image elf header is not sane\n");
1082 return -EINVAL;
1083 }
1084
1085 /* Read in all elf headers. */
1086 elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1087 elfcorebuf_sz = elfcorebuf_sz_orig;
1088 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1089 get_order(elfcorebuf_sz_orig));
1090 if (!elfcorebuf)
1091 return -ENOMEM;
1092 addr = elfcorehdr_addr;
1093 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1094 if (rc < 0)
1095 goto fail;
1096
1097 /* Merge all PT_NOTE headers into one. */
1098 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1099 &elfnotes_buf, &elfnotes_sz);
1100 if (rc)
1101 goto fail;
1102 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1103 elfnotes_sz, &vmcore_list);
1104 if (rc)
1105 goto fail;
1106 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1107 return 0;
1108fail:
1109 free_elfcorebuf();
1110 return rc;
1111}
1112
1113static int __init parse_crash_elf_headers(void)
1114{
1115 unsigned char e_ident[EI_NIDENT];
1116 u64 addr;
1117 int rc=0;
1118
1119 addr = elfcorehdr_addr;
1120 rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1121 if (rc < 0)
1122 return rc;
1123 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1124 pr_warn("Warning: Core image elf header not found\n");
1125 return -EINVAL;
1126 }
1127
1128 if (e_ident[EI_CLASS] == ELFCLASS64) {
1129 rc = parse_crash_elf64_headers();
1130 if (rc)
1131 return rc;
1132 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
1133 rc = parse_crash_elf32_headers();
1134 if (rc)
1135 return rc;
1136 } else {
1137 pr_warn("Warning: Core image elf header is not sane\n");
1138 return -EINVAL;
1139 }
1140
1141 /* Determine vmcore size. */
1142 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1143 &vmcore_list);
1144
1145 return 0;
1146}
1147
1148/* Init function for vmcore module. */
1149static int __init vmcore_init(void)
1150{
1151 int rc = 0;
1152
1153 /* Allow architectures to allocate ELF header in 2nd kernel */
1154 rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1155 if (rc)
1156 return rc;
1157 /*
1158 * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1159 * then capture the dump.
1160 */
1161 if (!(is_vmcore_usable()))
1162 return rc;
1163 rc = parse_crash_elf_headers();
1164 if (rc) {
1165 pr_warn("Kdump: vmcore not initialized\n");
1166 return rc;
1167 }
1168 elfcorehdr_free(elfcorehdr_addr);
1169 elfcorehdr_addr = ELFCORE_ADDR_ERR;
1170
1171 proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
1172 if (proc_vmcore)
1173 proc_vmcore->size = vmcore_size;
1174 return 0;
1175}
1176fs_initcall(vmcore_init);
1177
1178/* Cleanup function for vmcore module. */
1179void vmcore_cleanup(void)
1180{
1181 struct list_head *pos, *next;
1182
1183 if (proc_vmcore) {
1184 proc_remove(proc_vmcore);
1185 proc_vmcore = NULL;
1186 }
1187
1188 /* clear the vmcore list. */
1189 list_for_each_safe(pos, next, &vmcore_list) {
1190 struct vmcore *m;
1191
1192 m = list_entry(pos, struct vmcore, list);
1193 list_del(&m->list);
1194 kfree(m);
1195 }
1196 free_elfcorebuf();
1197}
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/io.h>
31#include "internal.h"
32
33/* List representing chunks of contiguous memory areas and their offsets in
34 * vmcore file.
35 */
36static LIST_HEAD(vmcore_list);
37
38/* Stores the pointer to the buffer containing kernel elf core headers. */
39static char *elfcorebuf;
40static size_t elfcorebuf_sz;
41static size_t elfcorebuf_sz_orig;
42
43static char *elfnotes_buf;
44static size_t elfnotes_sz;
45/* Size of all notes minus the device dump notes */
46static size_t elfnotes_orig_sz;
47
48/* Total size of vmcore file. */
49static u64 vmcore_size;
50
51static 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 */
55static LIST_HEAD(vmcoredd_list);
56static DEFINE_MUTEX(vmcoredd_mutex);
57
58static bool vmcoredd_disabled;
59core_param(novmcoredd, vmcoredd_disabled, bool, 0);
60#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
61
62/* Device Dump Size */
63static size_t vmcoredd_orig_sz;
64
65/*
66 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
67 * The called function has to take care of module refcounting.
68 */
69static int (*oldmem_pfn_is_ram)(unsigned long pfn);
70
71int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
72{
73 if (oldmem_pfn_is_ram)
74 return -EBUSY;
75 oldmem_pfn_is_ram = fn;
76 return 0;
77}
78EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
79
80void unregister_oldmem_pfn_is_ram(void)
81{
82 oldmem_pfn_is_ram = NULL;
83 wmb();
84}
85EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
86
87static int pfn_is_ram(unsigned long pfn)
88{
89 int (*fn)(unsigned long pfn);
90 /* pfn is ram unless fn() checks pagetype */
91 int ret = 1;
92
93 /*
94 * Ask hypervisor if the pfn is really ram.
95 * A ballooned page contains no data and reading from such a page
96 * will cause high load in the hypervisor.
97 */
98 fn = oldmem_pfn_is_ram;
99 if (fn)
100 ret = fn(pfn);
101
102 return ret;
103}
104
105/* Reads a page from the oldmem device from given offset. */
106ssize_t read_from_oldmem(char *buf, size_t count,
107 u64 *ppos, int userbuf,
108 bool encrypted)
109{
110 unsigned long pfn, offset;
111 size_t nr_bytes;
112 ssize_t read = 0, tmp;
113
114 if (!count)
115 return 0;
116
117 offset = (unsigned long)(*ppos % PAGE_SIZE);
118 pfn = (unsigned long)(*ppos / PAGE_SIZE);
119
120 do {
121 if (count > (PAGE_SIZE - offset))
122 nr_bytes = PAGE_SIZE - offset;
123 else
124 nr_bytes = count;
125
126 /* If pfn is not ram, return zeros for sparse dump files */
127 if (pfn_is_ram(pfn) == 0)
128 memset(buf, 0, nr_bytes);
129 else {
130 if (encrypted)
131 tmp = copy_oldmem_page_encrypted(pfn, buf,
132 nr_bytes,
133 offset,
134 userbuf);
135 else
136 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
137 offset, userbuf);
138
139 if (tmp < 0)
140 return tmp;
141 }
142 *ppos += nr_bytes;
143 count -= nr_bytes;
144 buf += nr_bytes;
145 read += nr_bytes;
146 ++pfn;
147 offset = 0;
148 } while (count);
149
150 return read;
151}
152
153/*
154 * Architectures may override this function to allocate ELF header in 2nd kernel
155 */
156int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
157{
158 return 0;
159}
160
161/*
162 * Architectures may override this function to free header
163 */
164void __weak elfcorehdr_free(unsigned long long addr)
165{}
166
167/*
168 * Architectures may override this function to read from ELF header
169 */
170ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
171{
172 return read_from_oldmem(buf, count, ppos, 0, false);
173}
174
175/*
176 * Architectures may override this function to read from notes sections
177 */
178ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
179{
180 return read_from_oldmem(buf, count, ppos, 0, mem_encrypt_active());
181}
182
183/*
184 * Architectures may override this function to map oldmem
185 */
186int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
187 unsigned long from, unsigned long pfn,
188 unsigned long size, pgprot_t prot)
189{
190 prot = pgprot_encrypted(prot);
191 return remap_pfn_range(vma, from, pfn, size, prot);
192}
193
194/*
195 * Architectures which support memory encryption override this.
196 */
197ssize_t __weak
198copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
199 unsigned long offset, int userbuf)
200{
201 return copy_oldmem_page(pfn, buf, csize, offset, userbuf);
202}
203
204/*
205 * Copy to either kernel or user space
206 */
207static int copy_to(void *target, void *src, size_t size, int userbuf)
208{
209 if (userbuf) {
210 if (copy_to_user((char __user *) target, src, size))
211 return -EFAULT;
212 } else {
213 memcpy(target, src, size);
214 }
215 return 0;
216}
217
218#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
219static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
220{
221 struct vmcoredd_node *dump;
222 u64 offset = 0;
223 int ret = 0;
224 size_t tsz;
225 char *buf;
226
227 mutex_lock(&vmcoredd_mutex);
228 list_for_each_entry(dump, &vmcoredd_list, list) {
229 if (start < offset + dump->size) {
230 tsz = min(offset + (u64)dump->size - start, (u64)size);
231 buf = dump->buf + start - offset;
232 if (copy_to(dst, buf, tsz, userbuf)) {
233 ret = -EFAULT;
234 goto out_unlock;
235 }
236
237 size -= tsz;
238 start += tsz;
239 dst += tsz;
240
241 /* Leave now if buffer filled already */
242 if (!size)
243 goto out_unlock;
244 }
245 offset += dump->size;
246 }
247
248out_unlock:
249 mutex_unlock(&vmcoredd_mutex);
250 return ret;
251}
252
253#ifdef CONFIG_MMU
254static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst,
255 u64 start, size_t size)
256{
257 struct vmcoredd_node *dump;
258 u64 offset = 0;
259 int ret = 0;
260 size_t tsz;
261 char *buf;
262
263 mutex_lock(&vmcoredd_mutex);
264 list_for_each_entry(dump, &vmcoredd_list, list) {
265 if (start < offset + dump->size) {
266 tsz = min(offset + (u64)dump->size - start, (u64)size);
267 buf = dump->buf + start - offset;
268 if (remap_vmalloc_range_partial(vma, dst, buf, 0,
269 tsz)) {
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
285out_unlock:
286 mutex_unlock(&vmcoredd_mutex);
287 return ret;
288}
289#endif /* CONFIG_MMU */
290#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
291
292/* Read from the ELF header and then the crash dump. On error, negative value is
293 * returned otherwise number of bytes read are returned.
294 */
295static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
296 int userbuf)
297{
298 ssize_t acc = 0, tmp;
299 size_t tsz;
300 u64 start;
301 struct vmcore *m = NULL;
302
303 if (buflen == 0 || *fpos >= vmcore_size)
304 return 0;
305
306 /* trim buflen to not go beyond EOF */
307 if (buflen > vmcore_size - *fpos)
308 buflen = vmcore_size - *fpos;
309
310 /* Read ELF core header */
311 if (*fpos < elfcorebuf_sz) {
312 tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
313 if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
314 return -EFAULT;
315 buflen -= tsz;
316 *fpos += tsz;
317 buffer += tsz;
318 acc += tsz;
319
320 /* leave now if filled buffer already */
321 if (buflen == 0)
322 return acc;
323 }
324
325 /* Read Elf note segment */
326 if (*fpos < elfcorebuf_sz + elfnotes_sz) {
327 void *kaddr;
328
329 /* We add device dumps before other elf notes because the
330 * other elf notes may not fill the elf notes buffer
331 * completely and we will end up with zero-filled data
332 * between the elf notes and the device dumps. Tools will
333 * then try to decode this zero-filled data as valid notes
334 * and we don't want that. Hence, adding device dumps before
335 * the other elf notes ensure that zero-filled data can be
336 * avoided.
337 */
338#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
339 /* Read device dumps */
340 if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
341 tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
342 (size_t)*fpos, buflen);
343 start = *fpos - elfcorebuf_sz;
344 if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf))
345 return -EFAULT;
346
347 buflen -= tsz;
348 *fpos += tsz;
349 buffer += tsz;
350 acc += tsz;
351
352 /* leave now if filled buffer already */
353 if (!buflen)
354 return acc;
355 }
356#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
357
358 /* Read remaining elf notes */
359 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
360 kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
361 if (copy_to(buffer, kaddr, tsz, userbuf))
362 return -EFAULT;
363
364 buflen -= tsz;
365 *fpos += tsz;
366 buffer += tsz;
367 acc += tsz;
368
369 /* leave now if filled buffer already */
370 if (buflen == 0)
371 return acc;
372 }
373
374 list_for_each_entry(m, &vmcore_list, list) {
375 if (*fpos < m->offset + m->size) {
376 tsz = (size_t)min_t(unsigned long long,
377 m->offset + m->size - *fpos,
378 buflen);
379 start = m->paddr + *fpos - m->offset;
380 tmp = read_from_oldmem(buffer, tsz, &start,
381 userbuf, mem_encrypt_active());
382 if (tmp < 0)
383 return tmp;
384 buflen -= tsz;
385 *fpos += tsz;
386 buffer += tsz;
387 acc += tsz;
388
389 /* leave now if filled buffer already */
390 if (buflen == 0)
391 return acc;
392 }
393 }
394
395 return acc;
396}
397
398static ssize_t read_vmcore(struct file *file, char __user *buffer,
399 size_t buflen, loff_t *fpos)
400{
401 return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
402}
403
404/*
405 * The vmcore fault handler uses the page cache and fills data using the
406 * standard __vmcore_read() function.
407 *
408 * On s390 the fault handler is used for memory regions that can't be mapped
409 * directly with remap_pfn_range().
410 */
411static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
412{
413#ifdef CONFIG_S390
414 struct address_space *mapping = vmf->vma->vm_file->f_mapping;
415 pgoff_t index = vmf->pgoff;
416 struct page *page;
417 loff_t offset;
418 char *buf;
419 int rc;
420
421 page = find_or_create_page(mapping, index, GFP_KERNEL);
422 if (!page)
423 return VM_FAULT_OOM;
424 if (!PageUptodate(page)) {
425 offset = (loff_t) index << PAGE_SHIFT;
426 buf = __va((page_to_pfn(page) << PAGE_SHIFT));
427 rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
428 if (rc < 0) {
429 unlock_page(page);
430 put_page(page);
431 return vmf_error(rc);
432 }
433 SetPageUptodate(page);
434 }
435 unlock_page(page);
436 vmf->page = page;
437 return 0;
438#else
439 return VM_FAULT_SIGBUS;
440#endif
441}
442
443static const struct vm_operations_struct vmcore_mmap_ops = {
444 .fault = mmap_vmcore_fault,
445};
446
447/**
448 * vmcore_alloc_buf - allocate buffer in vmalloc memory
449 * @sizez: size of buffer
450 *
451 * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
452 * the buffer to user-space by means of remap_vmalloc_range().
453 *
454 * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
455 * disabled and there's no need to allow users to mmap the buffer.
456 */
457static inline char *vmcore_alloc_buf(size_t size)
458{
459#ifdef CONFIG_MMU
460 return vmalloc_user(size);
461#else
462 return vzalloc(size);
463#endif
464}
465
466/*
467 * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
468 * essential for mmap_vmcore() in order to map physically
469 * non-contiguous objects (ELF header, ELF note segment and memory
470 * regions in the 1st kernel pointed to by PT_LOAD entries) into
471 * virtually contiguous user-space in ELF layout.
472 */
473#ifdef CONFIG_MMU
474/*
475 * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
476 * reported as not being ram with the zero page.
477 *
478 * @vma: vm_area_struct describing requested mapping
479 * @from: start remapping from
480 * @pfn: page frame number to start remapping to
481 * @size: remapping size
482 * @prot: protection bits
483 *
484 * Returns zero on success, -EAGAIN on failure.
485 */
486static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
487 unsigned long from, unsigned long pfn,
488 unsigned long size, pgprot_t prot)
489{
490 unsigned long map_size;
491 unsigned long pos_start, pos_end, pos;
492 unsigned long zeropage_pfn = my_zero_pfn(0);
493 size_t len = 0;
494
495 pos_start = pfn;
496 pos_end = pfn + (size >> PAGE_SHIFT);
497
498 for (pos = pos_start; pos < pos_end; ++pos) {
499 if (!pfn_is_ram(pos)) {
500 /*
501 * We hit a page which is not ram. Remap the continuous
502 * region between pos_start and pos-1 and replace
503 * the non-ram page at pos with the zero page.
504 */
505 if (pos > pos_start) {
506 /* Remap continuous region */
507 map_size = (pos - pos_start) << PAGE_SHIFT;
508 if (remap_oldmem_pfn_range(vma, from + len,
509 pos_start, map_size,
510 prot))
511 goto fail;
512 len += map_size;
513 }
514 /* Remap the zero page */
515 if (remap_oldmem_pfn_range(vma, from + len,
516 zeropage_pfn,
517 PAGE_SIZE, prot))
518 goto fail;
519 len += PAGE_SIZE;
520 pos_start = pos + 1;
521 }
522 }
523 if (pos > pos_start) {
524 /* Remap the rest */
525 map_size = (pos - pos_start) << PAGE_SHIFT;
526 if (remap_oldmem_pfn_range(vma, from + len, pos_start,
527 map_size, prot))
528 goto fail;
529 }
530 return 0;
531fail:
532 do_munmap(vma->vm_mm, from, len, NULL);
533 return -EAGAIN;
534}
535
536static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
537 unsigned long from, unsigned long pfn,
538 unsigned long size, pgprot_t prot)
539{
540 /*
541 * Check if oldmem_pfn_is_ram was registered to avoid
542 * looping over all pages without a reason.
543 */
544 if (oldmem_pfn_is_ram)
545 return remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
546 else
547 return remap_oldmem_pfn_range(vma, from, pfn, size, prot);
548}
549
550static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
551{
552 size_t size = vma->vm_end - vma->vm_start;
553 u64 start, end, len, tsz;
554 struct vmcore *m;
555
556 start = (u64)vma->vm_pgoff << PAGE_SHIFT;
557 end = start + size;
558
559 if (size > vmcore_size || end > vmcore_size)
560 return -EINVAL;
561
562 if (vma->vm_flags & (VM_WRITE | VM_EXEC))
563 return -EPERM;
564
565 vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
566 vma->vm_flags |= VM_MIXEDMAP;
567 vma->vm_ops = &vmcore_mmap_ops;
568
569 len = 0;
570
571 if (start < elfcorebuf_sz) {
572 u64 pfn;
573
574 tsz = min(elfcorebuf_sz - (size_t)start, size);
575 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
576 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
577 vma->vm_page_prot))
578 return -EAGAIN;
579 size -= tsz;
580 start += tsz;
581 len += tsz;
582
583 if (size == 0)
584 return 0;
585 }
586
587 if (start < elfcorebuf_sz + elfnotes_sz) {
588 void *kaddr;
589
590 /* We add device dumps before other elf notes because the
591 * other elf notes may not fill the elf notes buffer
592 * completely and we will end up with zero-filled data
593 * between the elf notes and the device dumps. Tools will
594 * then try to decode this zero-filled data as valid notes
595 * and we don't want that. Hence, adding device dumps before
596 * the other elf notes ensure that zero-filled data can be
597 * avoided. This also ensures that the device dumps and
598 * other elf notes can be properly mmaped at page aligned
599 * address.
600 */
601#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
602 /* Read device dumps */
603 if (start < elfcorebuf_sz + vmcoredd_orig_sz) {
604 u64 start_off;
605
606 tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
607 (size_t)start, size);
608 start_off = start - elfcorebuf_sz;
609 if (vmcoredd_mmap_dumps(vma, vma->vm_start + len,
610 start_off, tsz))
611 goto fail;
612
613 size -= tsz;
614 start += tsz;
615 len += tsz;
616
617 /* leave now if filled buffer already */
618 if (!size)
619 return 0;
620 }
621#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
622
623 /* Read remaining elf notes */
624 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
625 kaddr = elfnotes_buf + start - elfcorebuf_sz - vmcoredd_orig_sz;
626 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
627 kaddr, 0, tsz))
628 goto fail;
629
630 size -= tsz;
631 start += tsz;
632 len += tsz;
633
634 if (size == 0)
635 return 0;
636 }
637
638 list_for_each_entry(m, &vmcore_list, list) {
639 if (start < m->offset + m->size) {
640 u64 paddr = 0;
641
642 tsz = (size_t)min_t(unsigned long long,
643 m->offset + m->size - start, size);
644 paddr = m->paddr + start - m->offset;
645 if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
646 paddr >> PAGE_SHIFT, tsz,
647 vma->vm_page_prot))
648 goto fail;
649 size -= tsz;
650 start += tsz;
651 len += tsz;
652
653 if (size == 0)
654 return 0;
655 }
656 }
657
658 return 0;
659fail:
660 do_munmap(vma->vm_mm, vma->vm_start, len, NULL);
661 return -EAGAIN;
662}
663#else
664static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
665{
666 return -ENOSYS;
667}
668#endif
669
670static const struct proc_ops vmcore_proc_ops = {
671 .proc_read = read_vmcore,
672 .proc_lseek = default_llseek,
673 .proc_mmap = mmap_vmcore,
674};
675
676static struct vmcore* __init get_new_element(void)
677{
678 return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
679}
680
681static u64 get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
682 struct list_head *vc_list)
683{
684 u64 size;
685 struct vmcore *m;
686
687 size = elfsz + elfnotesegsz;
688 list_for_each_entry(m, vc_list, list) {
689 size += m->size;
690 }
691 return size;
692}
693
694/**
695 * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
696 *
697 * @ehdr_ptr: ELF header
698 *
699 * This function updates p_memsz member of each PT_NOTE entry in the
700 * program header table pointed to by @ehdr_ptr to real size of ELF
701 * note segment.
702 */
703static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
704{
705 int i, rc=0;
706 Elf64_Phdr *phdr_ptr;
707 Elf64_Nhdr *nhdr_ptr;
708
709 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
710 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
711 void *notes_section;
712 u64 offset, max_sz, sz, real_sz = 0;
713 if (phdr_ptr->p_type != PT_NOTE)
714 continue;
715 max_sz = phdr_ptr->p_memsz;
716 offset = phdr_ptr->p_offset;
717 notes_section = kmalloc(max_sz, GFP_KERNEL);
718 if (!notes_section)
719 return -ENOMEM;
720 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
721 if (rc < 0) {
722 kfree(notes_section);
723 return rc;
724 }
725 nhdr_ptr = notes_section;
726 while (nhdr_ptr->n_namesz != 0) {
727 sz = sizeof(Elf64_Nhdr) +
728 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
729 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
730 if ((real_sz + sz) > max_sz) {
731 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
732 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
733 break;
734 }
735 real_sz += sz;
736 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
737 }
738 kfree(notes_section);
739 phdr_ptr->p_memsz = real_sz;
740 if (real_sz == 0) {
741 pr_warn("Warning: Zero PT_NOTE entries found\n");
742 }
743 }
744
745 return 0;
746}
747
748/**
749 * get_note_number_and_size_elf64 - get the number of PT_NOTE program
750 * headers and sum of real size of their ELF note segment headers and
751 * data.
752 *
753 * @ehdr_ptr: ELF header
754 * @nr_ptnote: buffer for the number of PT_NOTE program headers
755 * @sz_ptnote: buffer for size of unique PT_NOTE program header
756 *
757 * This function is used to merge multiple PT_NOTE program headers
758 * into a unique single one. The resulting unique entry will have
759 * @sz_ptnote in its phdr->p_mem.
760 *
761 * It is assumed that program headers with PT_NOTE type pointed to by
762 * @ehdr_ptr has already been updated by update_note_header_size_elf64
763 * and each of PT_NOTE program headers has actual ELF note segment
764 * size in its p_memsz member.
765 */
766static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
767 int *nr_ptnote, u64 *sz_ptnote)
768{
769 int i;
770 Elf64_Phdr *phdr_ptr;
771
772 *nr_ptnote = *sz_ptnote = 0;
773
774 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
775 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
776 if (phdr_ptr->p_type != PT_NOTE)
777 continue;
778 *nr_ptnote += 1;
779 *sz_ptnote += phdr_ptr->p_memsz;
780 }
781
782 return 0;
783}
784
785/**
786 * copy_notes_elf64 - copy ELF note segments in a given buffer
787 *
788 * @ehdr_ptr: ELF header
789 * @notes_buf: buffer into which ELF note segments are copied
790 *
791 * This function is used to copy ELF note segment in the 1st kernel
792 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
793 * size of the buffer @notes_buf is equal to or larger than sum of the
794 * real ELF note segment headers and data.
795 *
796 * It is assumed that program headers with PT_NOTE type pointed to by
797 * @ehdr_ptr has already been updated by update_note_header_size_elf64
798 * and each of PT_NOTE program headers has actual ELF note segment
799 * size in its p_memsz member.
800 */
801static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
802{
803 int i, rc=0;
804 Elf64_Phdr *phdr_ptr;
805
806 phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
807
808 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
809 u64 offset;
810 if (phdr_ptr->p_type != PT_NOTE)
811 continue;
812 offset = phdr_ptr->p_offset;
813 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
814 &offset);
815 if (rc < 0)
816 return rc;
817 notes_buf += phdr_ptr->p_memsz;
818 }
819
820 return 0;
821}
822
823/* Merges all the PT_NOTE headers into one. */
824static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
825 char **notes_buf, size_t *notes_sz)
826{
827 int i, nr_ptnote=0, rc=0;
828 char *tmp;
829 Elf64_Ehdr *ehdr_ptr;
830 Elf64_Phdr phdr;
831 u64 phdr_sz = 0, note_off;
832
833 ehdr_ptr = (Elf64_Ehdr *)elfptr;
834
835 rc = update_note_header_size_elf64(ehdr_ptr);
836 if (rc < 0)
837 return rc;
838
839 rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
840 if (rc < 0)
841 return rc;
842
843 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
844 *notes_buf = vmcore_alloc_buf(*notes_sz);
845 if (!*notes_buf)
846 return -ENOMEM;
847
848 rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
849 if (rc < 0)
850 return rc;
851
852 /* Prepare merged PT_NOTE program header. */
853 phdr.p_type = PT_NOTE;
854 phdr.p_flags = 0;
855 note_off = sizeof(Elf64_Ehdr) +
856 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
857 phdr.p_offset = roundup(note_off, PAGE_SIZE);
858 phdr.p_vaddr = phdr.p_paddr = 0;
859 phdr.p_filesz = phdr.p_memsz = phdr_sz;
860 phdr.p_align = 0;
861
862 /* Add merged PT_NOTE program header*/
863 tmp = elfptr + sizeof(Elf64_Ehdr);
864 memcpy(tmp, &phdr, sizeof(phdr));
865 tmp += sizeof(phdr);
866
867 /* Remove unwanted PT_NOTE program headers. */
868 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
869 *elfsz = *elfsz - i;
870 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
871 memset(elfptr + *elfsz, 0, i);
872 *elfsz = roundup(*elfsz, PAGE_SIZE);
873
874 /* Modify e_phnum to reflect merged headers. */
875 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
876
877 /* Store the size of all notes. We need this to update the note
878 * header when the device dumps will be added.
879 */
880 elfnotes_orig_sz = phdr.p_memsz;
881
882 return 0;
883}
884
885/**
886 * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
887 *
888 * @ehdr_ptr: ELF header
889 *
890 * This function updates p_memsz member of each PT_NOTE entry in the
891 * program header table pointed to by @ehdr_ptr to real size of ELF
892 * note segment.
893 */
894static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
895{
896 int i, rc=0;
897 Elf32_Phdr *phdr_ptr;
898 Elf32_Nhdr *nhdr_ptr;
899
900 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
901 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
902 void *notes_section;
903 u64 offset, max_sz, sz, real_sz = 0;
904 if (phdr_ptr->p_type != PT_NOTE)
905 continue;
906 max_sz = phdr_ptr->p_memsz;
907 offset = phdr_ptr->p_offset;
908 notes_section = kmalloc(max_sz, GFP_KERNEL);
909 if (!notes_section)
910 return -ENOMEM;
911 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
912 if (rc < 0) {
913 kfree(notes_section);
914 return rc;
915 }
916 nhdr_ptr = notes_section;
917 while (nhdr_ptr->n_namesz != 0) {
918 sz = sizeof(Elf32_Nhdr) +
919 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
920 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
921 if ((real_sz + sz) > max_sz) {
922 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
923 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
924 break;
925 }
926 real_sz += sz;
927 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
928 }
929 kfree(notes_section);
930 phdr_ptr->p_memsz = real_sz;
931 if (real_sz == 0) {
932 pr_warn("Warning: Zero PT_NOTE entries found\n");
933 }
934 }
935
936 return 0;
937}
938
939/**
940 * get_note_number_and_size_elf32 - get the number of PT_NOTE program
941 * headers and sum of real size of their ELF note segment headers and
942 * data.
943 *
944 * @ehdr_ptr: ELF header
945 * @nr_ptnote: buffer for the number of PT_NOTE program headers
946 * @sz_ptnote: buffer for size of unique PT_NOTE program header
947 *
948 * This function is used to merge multiple PT_NOTE program headers
949 * into a unique single one. The resulting unique entry will have
950 * @sz_ptnote in its phdr->p_mem.
951 *
952 * It is assumed that program headers with PT_NOTE type pointed to by
953 * @ehdr_ptr has already been updated by update_note_header_size_elf32
954 * and each of PT_NOTE program headers has actual ELF note segment
955 * size in its p_memsz member.
956 */
957static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
958 int *nr_ptnote, u64 *sz_ptnote)
959{
960 int i;
961 Elf32_Phdr *phdr_ptr;
962
963 *nr_ptnote = *sz_ptnote = 0;
964
965 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
966 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
967 if (phdr_ptr->p_type != PT_NOTE)
968 continue;
969 *nr_ptnote += 1;
970 *sz_ptnote += phdr_ptr->p_memsz;
971 }
972
973 return 0;
974}
975
976/**
977 * copy_notes_elf32 - copy ELF note segments in a given buffer
978 *
979 * @ehdr_ptr: ELF header
980 * @notes_buf: buffer into which ELF note segments are copied
981 *
982 * This function is used to copy ELF note segment in the 1st kernel
983 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
984 * size of the buffer @notes_buf is equal to or larger than sum of the
985 * real ELF note segment headers and data.
986 *
987 * It is assumed that program headers with PT_NOTE type pointed to by
988 * @ehdr_ptr has already been updated by update_note_header_size_elf32
989 * and each of PT_NOTE program headers has actual ELF note segment
990 * size in its p_memsz member.
991 */
992static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
993{
994 int i, rc=0;
995 Elf32_Phdr *phdr_ptr;
996
997 phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
998
999 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1000 u64 offset;
1001 if (phdr_ptr->p_type != PT_NOTE)
1002 continue;
1003 offset = phdr_ptr->p_offset;
1004 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
1005 &offset);
1006 if (rc < 0)
1007 return rc;
1008 notes_buf += phdr_ptr->p_memsz;
1009 }
1010
1011 return 0;
1012}
1013
1014/* Merges all the PT_NOTE headers into one. */
1015static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
1016 char **notes_buf, size_t *notes_sz)
1017{
1018 int i, nr_ptnote=0, rc=0;
1019 char *tmp;
1020 Elf32_Ehdr *ehdr_ptr;
1021 Elf32_Phdr phdr;
1022 u64 phdr_sz = 0, note_off;
1023
1024 ehdr_ptr = (Elf32_Ehdr *)elfptr;
1025
1026 rc = update_note_header_size_elf32(ehdr_ptr);
1027 if (rc < 0)
1028 return rc;
1029
1030 rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
1031 if (rc < 0)
1032 return rc;
1033
1034 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
1035 *notes_buf = vmcore_alloc_buf(*notes_sz);
1036 if (!*notes_buf)
1037 return -ENOMEM;
1038
1039 rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
1040 if (rc < 0)
1041 return rc;
1042
1043 /* Prepare merged PT_NOTE program header. */
1044 phdr.p_type = PT_NOTE;
1045 phdr.p_flags = 0;
1046 note_off = sizeof(Elf32_Ehdr) +
1047 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
1048 phdr.p_offset = roundup(note_off, PAGE_SIZE);
1049 phdr.p_vaddr = phdr.p_paddr = 0;
1050 phdr.p_filesz = phdr.p_memsz = phdr_sz;
1051 phdr.p_align = 0;
1052
1053 /* Add merged PT_NOTE program header*/
1054 tmp = elfptr + sizeof(Elf32_Ehdr);
1055 memcpy(tmp, &phdr, sizeof(phdr));
1056 tmp += sizeof(phdr);
1057
1058 /* Remove unwanted PT_NOTE program headers. */
1059 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
1060 *elfsz = *elfsz - i;
1061 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
1062 memset(elfptr + *elfsz, 0, i);
1063 *elfsz = roundup(*elfsz, PAGE_SIZE);
1064
1065 /* Modify e_phnum to reflect merged headers. */
1066 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
1067
1068 /* Store the size of all notes. We need this to update the note
1069 * header when the device dumps will be added.
1070 */
1071 elfnotes_orig_sz = phdr.p_memsz;
1072
1073 return 0;
1074}
1075
1076/* Add memory chunks represented by program headers to vmcore list. Also update
1077 * the new offset fields of exported program headers. */
1078static int __init process_ptload_program_headers_elf64(char *elfptr,
1079 size_t elfsz,
1080 size_t elfnotes_sz,
1081 struct list_head *vc_list)
1082{
1083 int i;
1084 Elf64_Ehdr *ehdr_ptr;
1085 Elf64_Phdr *phdr_ptr;
1086 loff_t vmcore_off;
1087 struct vmcore *new;
1088
1089 ehdr_ptr = (Elf64_Ehdr *)elfptr;
1090 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
1091
1092 /* Skip Elf header, program headers and Elf note segment. */
1093 vmcore_off = elfsz + elfnotes_sz;
1094
1095 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1096 u64 paddr, start, end, size;
1097
1098 if (phdr_ptr->p_type != PT_LOAD)
1099 continue;
1100
1101 paddr = phdr_ptr->p_offset;
1102 start = rounddown(paddr, PAGE_SIZE);
1103 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1104 size = end - start;
1105
1106 /* Add this contiguous chunk of memory to vmcore list.*/
1107 new = get_new_element();
1108 if (!new)
1109 return -ENOMEM;
1110 new->paddr = start;
1111 new->size = size;
1112 list_add_tail(&new->list, vc_list);
1113
1114 /* Update the program header offset. */
1115 phdr_ptr->p_offset = vmcore_off + (paddr - start);
1116 vmcore_off = vmcore_off + size;
1117 }
1118 return 0;
1119}
1120
1121static int __init process_ptload_program_headers_elf32(char *elfptr,
1122 size_t elfsz,
1123 size_t elfnotes_sz,
1124 struct list_head *vc_list)
1125{
1126 int i;
1127 Elf32_Ehdr *ehdr_ptr;
1128 Elf32_Phdr *phdr_ptr;
1129 loff_t vmcore_off;
1130 struct vmcore *new;
1131
1132 ehdr_ptr = (Elf32_Ehdr *)elfptr;
1133 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_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
1164/* Sets offset fields of vmcore elements. */
1165static void set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
1166 struct list_head *vc_list)
1167{
1168 loff_t vmcore_off;
1169 struct vmcore *m;
1170
1171 /* Skip Elf header, program headers and Elf note segment. */
1172 vmcore_off = elfsz + elfnotes_sz;
1173
1174 list_for_each_entry(m, vc_list, list) {
1175 m->offset = vmcore_off;
1176 vmcore_off += m->size;
1177 }
1178}
1179
1180static void free_elfcorebuf(void)
1181{
1182 free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
1183 elfcorebuf = NULL;
1184 vfree(elfnotes_buf);
1185 elfnotes_buf = NULL;
1186}
1187
1188static int __init parse_crash_elf64_headers(void)
1189{
1190 int rc=0;
1191 Elf64_Ehdr ehdr;
1192 u64 addr;
1193
1194 addr = elfcorehdr_addr;
1195
1196 /* Read Elf header */
1197 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
1198 if (rc < 0)
1199 return rc;
1200
1201 /* Do some basic Verification. */
1202 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1203 (ehdr.e_type != ET_CORE) ||
1204 !vmcore_elf64_check_arch(&ehdr) ||
1205 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
1206 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1207 ehdr.e_version != EV_CURRENT ||
1208 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
1209 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
1210 ehdr.e_phnum == 0) {
1211 pr_warn("Warning: Core image elf header is not sane\n");
1212 return -EINVAL;
1213 }
1214
1215 /* Read in all elf headers. */
1216 elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
1217 ehdr.e_phnum * sizeof(Elf64_Phdr);
1218 elfcorebuf_sz = elfcorebuf_sz_orig;
1219 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1220 get_order(elfcorebuf_sz_orig));
1221 if (!elfcorebuf)
1222 return -ENOMEM;
1223 addr = elfcorehdr_addr;
1224 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1225 if (rc < 0)
1226 goto fail;
1227
1228 /* Merge all PT_NOTE headers into one. */
1229 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
1230 &elfnotes_buf, &elfnotes_sz);
1231 if (rc)
1232 goto fail;
1233 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
1234 elfnotes_sz, &vmcore_list);
1235 if (rc)
1236 goto fail;
1237 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1238 return 0;
1239fail:
1240 free_elfcorebuf();
1241 return rc;
1242}
1243
1244static int __init parse_crash_elf32_headers(void)
1245{
1246 int rc=0;
1247 Elf32_Ehdr ehdr;
1248 u64 addr;
1249
1250 addr = elfcorehdr_addr;
1251
1252 /* Read Elf header */
1253 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
1254 if (rc < 0)
1255 return rc;
1256
1257 /* Do some basic Verification. */
1258 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1259 (ehdr.e_type != ET_CORE) ||
1260 !vmcore_elf32_check_arch(&ehdr) ||
1261 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
1262 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1263 ehdr.e_version != EV_CURRENT ||
1264 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1265 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1266 ehdr.e_phnum == 0) {
1267 pr_warn("Warning: Core image elf header is not sane\n");
1268 return -EINVAL;
1269 }
1270
1271 /* Read in all elf headers. */
1272 elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1273 elfcorebuf_sz = elfcorebuf_sz_orig;
1274 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1275 get_order(elfcorebuf_sz_orig));
1276 if (!elfcorebuf)
1277 return -ENOMEM;
1278 addr = elfcorehdr_addr;
1279 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1280 if (rc < 0)
1281 goto fail;
1282
1283 /* Merge all PT_NOTE headers into one. */
1284 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1285 &elfnotes_buf, &elfnotes_sz);
1286 if (rc)
1287 goto fail;
1288 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1289 elfnotes_sz, &vmcore_list);
1290 if (rc)
1291 goto fail;
1292 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1293 return 0;
1294fail:
1295 free_elfcorebuf();
1296 return rc;
1297}
1298
1299static int __init parse_crash_elf_headers(void)
1300{
1301 unsigned char e_ident[EI_NIDENT];
1302 u64 addr;
1303 int rc=0;
1304
1305 addr = elfcorehdr_addr;
1306 rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1307 if (rc < 0)
1308 return rc;
1309 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1310 pr_warn("Warning: Core image elf header not found\n");
1311 return -EINVAL;
1312 }
1313
1314 if (e_ident[EI_CLASS] == ELFCLASS64) {
1315 rc = parse_crash_elf64_headers();
1316 if (rc)
1317 return rc;
1318 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
1319 rc = parse_crash_elf32_headers();
1320 if (rc)
1321 return rc;
1322 } else {
1323 pr_warn("Warning: Core image elf header is not sane\n");
1324 return -EINVAL;
1325 }
1326
1327 /* Determine vmcore size. */
1328 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1329 &vmcore_list);
1330
1331 return 0;
1332}
1333
1334#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1335/**
1336 * vmcoredd_write_header - Write vmcore device dump header at the
1337 * beginning of the dump's buffer.
1338 * @buf: Output buffer where the note is written
1339 * @data: Dump info
1340 * @size: Size of the dump
1341 *
1342 * Fills beginning of the dump's buffer with vmcore device dump header.
1343 */
1344static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data,
1345 u32 size)
1346{
1347 struct vmcoredd_header *vdd_hdr = (struct vmcoredd_header *)buf;
1348
1349 vdd_hdr->n_namesz = sizeof(vdd_hdr->name);
1350 vdd_hdr->n_descsz = size + sizeof(vdd_hdr->dump_name);
1351 vdd_hdr->n_type = NT_VMCOREDD;
1352
1353 strncpy((char *)vdd_hdr->name, VMCOREDD_NOTE_NAME,
1354 sizeof(vdd_hdr->name));
1355 memcpy(vdd_hdr->dump_name, data->dump_name, sizeof(vdd_hdr->dump_name));
1356}
1357
1358/**
1359 * vmcoredd_update_program_headers - Update all Elf program headers
1360 * @elfptr: Pointer to elf header
1361 * @elfnotesz: Size of elf notes aligned to page size
1362 * @vmcoreddsz: Size of device dumps to be added to elf note header
1363 *
1364 * Determine type of Elf header (Elf64 or Elf32) and update the elf note size.
1365 * Also update the offsets of all the program headers after the elf note header.
1366 */
1367static void vmcoredd_update_program_headers(char *elfptr, size_t elfnotesz,
1368 size_t vmcoreddsz)
1369{
1370 unsigned char *e_ident = (unsigned char *)elfptr;
1371 u64 start, end, size;
1372 loff_t vmcore_off;
1373 u32 i;
1374
1375 vmcore_off = elfcorebuf_sz + elfnotesz;
1376
1377 if (e_ident[EI_CLASS] == ELFCLASS64) {
1378 Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfptr;
1379 Elf64_Phdr *phdr = (Elf64_Phdr *)(elfptr + sizeof(Elf64_Ehdr));
1380
1381 /* Update all program headers */
1382 for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1383 if (phdr->p_type == PT_NOTE) {
1384 /* Update note size */
1385 phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1386 phdr->p_filesz = phdr->p_memsz;
1387 continue;
1388 }
1389
1390 start = rounddown(phdr->p_offset, PAGE_SIZE);
1391 end = roundup(phdr->p_offset + phdr->p_memsz,
1392 PAGE_SIZE);
1393 size = end - start;
1394 phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1395 vmcore_off += size;
1396 }
1397 } else {
1398 Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfptr;
1399 Elf32_Phdr *phdr = (Elf32_Phdr *)(elfptr + sizeof(Elf32_Ehdr));
1400
1401 /* Update all program headers */
1402 for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1403 if (phdr->p_type == PT_NOTE) {
1404 /* Update note size */
1405 phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1406 phdr->p_filesz = phdr->p_memsz;
1407 continue;
1408 }
1409
1410 start = rounddown(phdr->p_offset, PAGE_SIZE);
1411 end = roundup(phdr->p_offset + phdr->p_memsz,
1412 PAGE_SIZE);
1413 size = end - start;
1414 phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1415 vmcore_off += size;
1416 }
1417 }
1418}
1419
1420/**
1421 * vmcoredd_update_size - Update the total size of the device dumps and update
1422 * Elf header
1423 * @dump_size: Size of the current device dump to be added to total size
1424 *
1425 * Update the total size of all the device dumps and update the Elf program
1426 * headers. Calculate the new offsets for the vmcore list and update the
1427 * total vmcore size.
1428 */
1429static void vmcoredd_update_size(size_t dump_size)
1430{
1431 vmcoredd_orig_sz += dump_size;
1432 elfnotes_sz = roundup(elfnotes_orig_sz, PAGE_SIZE) + vmcoredd_orig_sz;
1433 vmcoredd_update_program_headers(elfcorebuf, elfnotes_sz,
1434 vmcoredd_orig_sz);
1435
1436 /* Update vmcore list offsets */
1437 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1438
1439 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1440 &vmcore_list);
1441 proc_vmcore->size = vmcore_size;
1442}
1443
1444/**
1445 * vmcore_add_device_dump - Add a buffer containing device dump to vmcore
1446 * @data: dump info.
1447 *
1448 * Allocate a buffer and invoke the calling driver's dump collect routine.
1449 * Write Elf note at the beginning of the buffer to indicate vmcore device
1450 * dump and add the dump to global list.
1451 */
1452int vmcore_add_device_dump(struct vmcoredd_data *data)
1453{
1454 struct vmcoredd_node *dump;
1455 void *buf = NULL;
1456 size_t data_size;
1457 int ret;
1458
1459 if (vmcoredd_disabled) {
1460 pr_err_once("Device dump is disabled\n");
1461 return -EINVAL;
1462 }
1463
1464 if (!data || !strlen(data->dump_name) ||
1465 !data->vmcoredd_callback || !data->size)
1466 return -EINVAL;
1467
1468 dump = vzalloc(sizeof(*dump));
1469 if (!dump) {
1470 ret = -ENOMEM;
1471 goto out_err;
1472 }
1473
1474 /* Keep size of the buffer page aligned so that it can be mmaped */
1475 data_size = roundup(sizeof(struct vmcoredd_header) + data->size,
1476 PAGE_SIZE);
1477
1478 /* Allocate buffer for driver's to write their dumps */
1479 buf = vmcore_alloc_buf(data_size);
1480 if (!buf) {
1481 ret = -ENOMEM;
1482 goto out_err;
1483 }
1484
1485 vmcoredd_write_header(buf, data, data_size -
1486 sizeof(struct vmcoredd_header));
1487
1488 /* Invoke the driver's dump collection routing */
1489 ret = data->vmcoredd_callback(data, buf +
1490 sizeof(struct vmcoredd_header));
1491 if (ret)
1492 goto out_err;
1493
1494 dump->buf = buf;
1495 dump->size = data_size;
1496
1497 /* Add the dump to driver sysfs list */
1498 mutex_lock(&vmcoredd_mutex);
1499 list_add_tail(&dump->list, &vmcoredd_list);
1500 mutex_unlock(&vmcoredd_mutex);
1501
1502 vmcoredd_update_size(data_size);
1503 return 0;
1504
1505out_err:
1506 vfree(buf);
1507 vfree(dump);
1508
1509 return ret;
1510}
1511EXPORT_SYMBOL(vmcore_add_device_dump);
1512#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1513
1514/* Free all dumps in vmcore device dump list */
1515static void vmcore_free_device_dumps(void)
1516{
1517#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1518 mutex_lock(&vmcoredd_mutex);
1519 while (!list_empty(&vmcoredd_list)) {
1520 struct vmcoredd_node *dump;
1521
1522 dump = list_first_entry(&vmcoredd_list, struct vmcoredd_node,
1523 list);
1524 list_del(&dump->list);
1525 vfree(dump->buf);
1526 vfree(dump);
1527 }
1528 mutex_unlock(&vmcoredd_mutex);
1529#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1530}
1531
1532/* Init function for vmcore module. */
1533static int __init vmcore_init(void)
1534{
1535 int rc = 0;
1536
1537 /* Allow architectures to allocate ELF header in 2nd kernel */
1538 rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1539 if (rc)
1540 return rc;
1541 /*
1542 * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1543 * then capture the dump.
1544 */
1545 if (!(is_vmcore_usable()))
1546 return rc;
1547 rc = parse_crash_elf_headers();
1548 if (rc) {
1549 pr_warn("Kdump: vmcore not initialized\n");
1550 return rc;
1551 }
1552 elfcorehdr_free(elfcorehdr_addr);
1553 elfcorehdr_addr = ELFCORE_ADDR_ERR;
1554
1555 proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &vmcore_proc_ops);
1556 if (proc_vmcore)
1557 proc_vmcore->size = vmcore_size;
1558 return 0;
1559}
1560fs_initcall(vmcore_init);
1561
1562/* Cleanup function for vmcore module. */
1563void vmcore_cleanup(void)
1564{
1565 if (proc_vmcore) {
1566 proc_remove(proc_vmcore);
1567 proc_vmcore = NULL;
1568 }
1569
1570 /* clear the vmcore list. */
1571 while (!list_empty(&vmcore_list)) {
1572 struct vmcore *m;
1573
1574 m = list_first_entry(&vmcore_list, struct vmcore, list);
1575 list_del(&m->list);
1576 kfree(m);
1577 }
1578 free_elfcorebuf();
1579
1580 /* clear vmcore device dump list */
1581 vmcore_free_device_dumps();
1582}