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
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>
29 /* List representing chunks of contiguous memory areas and their offsets in
32 static LIST_HEAD(vmcore_list);
34 /* Stores the pointer to the buffer containing kernel elf core headers. */
35 static char *elfcorebuf;
36 static size_t elfcorebuf_sz;
37 static size_t elfcorebuf_sz_orig;
39 static char *elfnotes_buf;
40 static size_t elfnotes_sz;
42 /* Total size of vmcore file. */
43 static u64 vmcore_size;
45 static struct proc_dir_entry *proc_vmcore = NULL;
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.
51 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
53 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
55 if (oldmem_pfn_is_ram)
57 oldmem_pfn_is_ram = fn;
60 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
62 void unregister_oldmem_pfn_is_ram(void)
64 oldmem_pfn_is_ram = NULL;
67 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
69 static int pfn_is_ram(unsigned long pfn)
71 int (*fn)(unsigned long pfn);
72 /* pfn is ram unless fn() checks pagetype */
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.
80 fn = oldmem_pfn_is_ram;
87 /* Reads a page from the oldmem device from given offset. */
88 static ssize_t read_from_oldmem(char *buf, size_t count,
89 u64 *ppos, int userbuf)
91 unsigned long pfn, offset;
93 ssize_t read = 0, tmp;
98 offset = (unsigned long)(*ppos % PAGE_SIZE);
99 pfn = (unsigned long)(*ppos / PAGE_SIZE);
102 if (count > (PAGE_SIZE - offset))
103 nr_bytes = PAGE_SIZE - offset;
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);
111 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
128 * Architectures may override this function to allocate ELF header in 2nd kernel
130 int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
136 * Architectures may override this function to free header
138 void __weak elfcorehdr_free(unsigned long long addr)
142 * Architectures may override this function to read from ELF header
144 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
146 return read_from_oldmem(buf, count, ppos, 0);
150 * Architectures may override this function to read from notes sections
152 ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
154 return read_from_oldmem(buf, count, ppos, 0);
158 * Architectures may override this function to map oldmem
160 int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
161 unsigned long from, unsigned long pfn,
162 unsigned long size, pgprot_t prot)
164 return remap_pfn_range(vma, from, pfn, size, prot);
168 * Copy to either kernel or user space
170 static int copy_to(void *target, void *src, size_t size, int userbuf)
173 if (copy_to_user((char __user *) target, src, size))
176 memcpy(target, src, size);
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.
184 static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
187 ssize_t acc = 0, tmp;
190 struct vmcore *m = NULL;
192 if (buflen == 0 || *fpos >= vmcore_size)
195 /* trim buflen to not go beyond EOF */
196 if (buflen > vmcore_size - *fpos)
197 buflen = vmcore_size - *fpos;
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))
209 /* leave now if filled buffer already */
214 /* Read Elf note segment */
215 if (*fpos < elfcorebuf_sz + elfnotes_sz) {
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))
227 /* leave now if filled buffer already */
232 list_for_each_entry(m, &vmcore_list, list) {
233 if (*fpos < m->offset + m->size) {
234 tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
235 start = m->paddr + *fpos - m->offset;
236 tmp = read_from_oldmem(buffer, tsz, &start, userbuf);
244 /* leave now if filled buffer already */
253 static ssize_t read_vmcore(struct file *file, char __user *buffer,
254 size_t buflen, loff_t *fpos)
256 return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
260 * The vmcore fault handler uses the page cache and fills data using the
261 * standard __vmcore_read() function.
263 * On s390 the fault handler is used for memory regions that can't be mapped
264 * directly with remap_pfn_range().
266 static int mmap_vmcore_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
269 struct address_space *mapping = vma->vm_file->f_mapping;
270 pgoff_t index = vmf->pgoff;
276 page = find_or_create_page(mapping, index, GFP_KERNEL);
279 if (!PageUptodate(page)) {
280 offset = (loff_t) index << PAGE_CACHE_SHIFT;
281 buf = __va((page_to_pfn(page) << PAGE_SHIFT));
282 rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
285 page_cache_release(page);
286 return (rc == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
288 SetPageUptodate(page);
294 return VM_FAULT_SIGBUS;
298 static const struct vm_operations_struct vmcore_mmap_ops = {
299 .fault = mmap_vmcore_fault,
303 * alloc_elfnotes_buf - allocate buffer for ELF note segment in
306 * @notes_sz: size of buffer
308 * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
309 * the buffer to user-space by means of remap_vmalloc_range().
311 * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
312 * disabled and there's no need to allow users to mmap the buffer.
314 static inline char *alloc_elfnotes_buf(size_t notes_sz)
317 return vmalloc_user(notes_sz);
319 return vzalloc(notes_sz);
324 * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
325 * essential for mmap_vmcore() in order to map physically
326 * non-contiguous objects (ELF header, ELF note segment and memory
327 * regions in the 1st kernel pointed to by PT_LOAD entries) into
328 * virtually contiguous user-space in ELF layout.
331 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
333 size_t size = vma->vm_end - vma->vm_start;
334 u64 start, end, len, tsz;
337 start = (u64)vma->vm_pgoff << PAGE_SHIFT;
340 if (size > vmcore_size || end > vmcore_size)
343 if (vma->vm_flags & (VM_WRITE | VM_EXEC))
346 vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
347 vma->vm_flags |= VM_MIXEDMAP;
348 vma->vm_ops = &vmcore_mmap_ops;
352 if (start < elfcorebuf_sz) {
355 tsz = min(elfcorebuf_sz - (size_t)start, size);
356 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
357 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
368 if (start < elfcorebuf_sz + elfnotes_sz) {
371 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
372 kaddr = elfnotes_buf + start - elfcorebuf_sz;
373 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
384 list_for_each_entry(m, &vmcore_list, list) {
385 if (start < m->offset + m->size) {
388 tsz = min_t(size_t, m->offset + m->size - start, size);
389 paddr = m->paddr + start - m->offset;
390 if (remap_oldmem_pfn_range(vma, vma->vm_start + len,
391 paddr >> PAGE_SHIFT, tsz,
405 do_munmap(vma->vm_mm, vma->vm_start, len);
409 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
415 static const struct file_operations proc_vmcore_operations = {
417 .llseek = default_llseek,
421 static struct vmcore* __init get_new_element(void)
423 return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
426 static u64 __init get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
427 struct list_head *vc_list)
432 size = elfsz + elfnotesegsz;
433 list_for_each_entry(m, vc_list, list) {
440 * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
442 * @ehdr_ptr: ELF header
444 * This function updates p_memsz member of each PT_NOTE entry in the
445 * program header table pointed to by @ehdr_ptr to real size of ELF
448 static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
451 Elf64_Phdr *phdr_ptr;
452 Elf64_Nhdr *nhdr_ptr;
454 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
455 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
457 u64 offset, max_sz, sz, real_sz = 0;
458 if (phdr_ptr->p_type != PT_NOTE)
460 max_sz = phdr_ptr->p_memsz;
461 offset = phdr_ptr->p_offset;
462 notes_section = kmalloc(max_sz, GFP_KERNEL);
465 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
467 kfree(notes_section);
470 nhdr_ptr = notes_section;
471 while (nhdr_ptr->n_namesz != 0) {
472 sz = sizeof(Elf64_Nhdr) +
473 ((nhdr_ptr->n_namesz + 3) & ~3) +
474 ((nhdr_ptr->n_descsz + 3) & ~3);
475 if ((real_sz + sz) > max_sz) {
476 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
477 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
481 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
483 kfree(notes_section);
484 phdr_ptr->p_memsz = real_sz;
486 pr_warn("Warning: Zero PT_NOTE entries found\n");
495 * get_note_number_and_size_elf64 - get the number of PT_NOTE program
496 * headers and sum of real size of their ELF note segment headers and
499 * @ehdr_ptr: ELF header
500 * @nr_ptnote: buffer for the number of PT_NOTE program headers
501 * @sz_ptnote: buffer for size of unique PT_NOTE program header
503 * This function is used to merge multiple PT_NOTE program headers
504 * into a unique single one. The resulting unique entry will have
505 * @sz_ptnote in its phdr->p_mem.
507 * It is assumed that program headers with PT_NOTE type pointed to by
508 * @ehdr_ptr has already been updated by update_note_header_size_elf64
509 * and each of PT_NOTE program headers has actual ELF note segment
510 * size in its p_memsz member.
512 static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
513 int *nr_ptnote, u64 *sz_ptnote)
516 Elf64_Phdr *phdr_ptr;
518 *nr_ptnote = *sz_ptnote = 0;
520 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
521 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
522 if (phdr_ptr->p_type != PT_NOTE)
525 *sz_ptnote += phdr_ptr->p_memsz;
532 * copy_notes_elf64 - copy ELF note segments in a given buffer
534 * @ehdr_ptr: ELF header
535 * @notes_buf: buffer into which ELF note segments are copied
537 * This function is used to copy ELF note segment in the 1st kernel
538 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
539 * size of the buffer @notes_buf is equal to or larger than sum of the
540 * real ELF note segment headers and data.
542 * It is assumed that program headers with PT_NOTE type pointed to by
543 * @ehdr_ptr has already been updated by update_note_header_size_elf64
544 * and each of PT_NOTE program headers has actual ELF note segment
545 * size in its p_memsz member.
547 static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
550 Elf64_Phdr *phdr_ptr;
552 phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
554 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
556 if (phdr_ptr->p_type != PT_NOTE)
558 offset = phdr_ptr->p_offset;
559 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
563 notes_buf += phdr_ptr->p_memsz;
569 /* Merges all the PT_NOTE headers into one. */
570 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
571 char **notes_buf, size_t *notes_sz)
573 int i, nr_ptnote=0, rc=0;
575 Elf64_Ehdr *ehdr_ptr;
577 u64 phdr_sz = 0, note_off;
579 ehdr_ptr = (Elf64_Ehdr *)elfptr;
581 rc = update_note_header_size_elf64(ehdr_ptr);
585 rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
589 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
590 *notes_buf = alloc_elfnotes_buf(*notes_sz);
594 rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
598 /* Prepare merged PT_NOTE program header. */
599 phdr.p_type = PT_NOTE;
601 note_off = sizeof(Elf64_Ehdr) +
602 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
603 phdr.p_offset = roundup(note_off, PAGE_SIZE);
604 phdr.p_vaddr = phdr.p_paddr = 0;
605 phdr.p_filesz = phdr.p_memsz = phdr_sz;
608 /* Add merged PT_NOTE program header*/
609 tmp = elfptr + sizeof(Elf64_Ehdr);
610 memcpy(tmp, &phdr, sizeof(phdr));
613 /* Remove unwanted PT_NOTE program headers. */
614 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
616 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
617 memset(elfptr + *elfsz, 0, i);
618 *elfsz = roundup(*elfsz, PAGE_SIZE);
620 /* Modify e_phnum to reflect merged headers. */
621 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
627 * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
629 * @ehdr_ptr: ELF header
631 * This function updates p_memsz member of each PT_NOTE entry in the
632 * program header table pointed to by @ehdr_ptr to real size of ELF
635 static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
638 Elf32_Phdr *phdr_ptr;
639 Elf32_Nhdr *nhdr_ptr;
641 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
642 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
644 u64 offset, max_sz, sz, real_sz = 0;
645 if (phdr_ptr->p_type != PT_NOTE)
647 max_sz = phdr_ptr->p_memsz;
648 offset = phdr_ptr->p_offset;
649 notes_section = kmalloc(max_sz, GFP_KERNEL);
652 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
654 kfree(notes_section);
657 nhdr_ptr = notes_section;
658 while (nhdr_ptr->n_namesz != 0) {
659 sz = sizeof(Elf32_Nhdr) +
660 ((nhdr_ptr->n_namesz + 3) & ~3) +
661 ((nhdr_ptr->n_descsz + 3) & ~3);
662 if ((real_sz + sz) > max_sz) {
663 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
664 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
668 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
670 kfree(notes_section);
671 phdr_ptr->p_memsz = real_sz;
673 pr_warn("Warning: Zero PT_NOTE entries found\n");
682 * get_note_number_and_size_elf32 - get the number of PT_NOTE program
683 * headers and sum of real size of their ELF note segment headers and
686 * @ehdr_ptr: ELF header
687 * @nr_ptnote: buffer for the number of PT_NOTE program headers
688 * @sz_ptnote: buffer for size of unique PT_NOTE program header
690 * This function is used to merge multiple PT_NOTE program headers
691 * into a unique single one. The resulting unique entry will have
692 * @sz_ptnote in its phdr->p_mem.
694 * It is assumed that program headers with PT_NOTE type pointed to by
695 * @ehdr_ptr has already been updated by update_note_header_size_elf32
696 * and each of PT_NOTE program headers has actual ELF note segment
697 * size in its p_memsz member.
699 static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
700 int *nr_ptnote, u64 *sz_ptnote)
703 Elf32_Phdr *phdr_ptr;
705 *nr_ptnote = *sz_ptnote = 0;
707 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
708 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
709 if (phdr_ptr->p_type != PT_NOTE)
712 *sz_ptnote += phdr_ptr->p_memsz;
719 * copy_notes_elf32 - copy ELF note segments in a given buffer
721 * @ehdr_ptr: ELF header
722 * @notes_buf: buffer into which ELF note segments are copied
724 * This function is used to copy ELF note segment in the 1st kernel
725 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
726 * size of the buffer @notes_buf is equal to or larger than sum of the
727 * real ELF note segment headers and data.
729 * It is assumed that program headers with PT_NOTE type pointed to by
730 * @ehdr_ptr has already been updated by update_note_header_size_elf32
731 * and each of PT_NOTE program headers has actual ELF note segment
732 * size in its p_memsz member.
734 static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
737 Elf32_Phdr *phdr_ptr;
739 phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
741 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
743 if (phdr_ptr->p_type != PT_NOTE)
745 offset = phdr_ptr->p_offset;
746 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
750 notes_buf += phdr_ptr->p_memsz;
756 /* Merges all the PT_NOTE headers into one. */
757 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
758 char **notes_buf, size_t *notes_sz)
760 int i, nr_ptnote=0, rc=0;
762 Elf32_Ehdr *ehdr_ptr;
764 u64 phdr_sz = 0, note_off;
766 ehdr_ptr = (Elf32_Ehdr *)elfptr;
768 rc = update_note_header_size_elf32(ehdr_ptr);
772 rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
776 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
777 *notes_buf = alloc_elfnotes_buf(*notes_sz);
781 rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
785 /* Prepare merged PT_NOTE program header. */
786 phdr.p_type = PT_NOTE;
788 note_off = sizeof(Elf32_Ehdr) +
789 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
790 phdr.p_offset = roundup(note_off, PAGE_SIZE);
791 phdr.p_vaddr = phdr.p_paddr = 0;
792 phdr.p_filesz = phdr.p_memsz = phdr_sz;
795 /* Add merged PT_NOTE program header*/
796 tmp = elfptr + sizeof(Elf32_Ehdr);
797 memcpy(tmp, &phdr, sizeof(phdr));
800 /* Remove unwanted PT_NOTE program headers. */
801 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
803 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
804 memset(elfptr + *elfsz, 0, i);
805 *elfsz = roundup(*elfsz, PAGE_SIZE);
807 /* Modify e_phnum to reflect merged headers. */
808 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
813 /* Add memory chunks represented by program headers to vmcore list. Also update
814 * the new offset fields of exported program headers. */
815 static int __init process_ptload_program_headers_elf64(char *elfptr,
818 struct list_head *vc_list)
821 Elf64_Ehdr *ehdr_ptr;
822 Elf64_Phdr *phdr_ptr;
826 ehdr_ptr = (Elf64_Ehdr *)elfptr;
827 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
829 /* Skip Elf header, program headers and Elf note segment. */
830 vmcore_off = elfsz + elfnotes_sz;
832 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
833 u64 paddr, start, end, size;
835 if (phdr_ptr->p_type != PT_LOAD)
838 paddr = phdr_ptr->p_offset;
839 start = rounddown(paddr, PAGE_SIZE);
840 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
843 /* Add this contiguous chunk of memory to vmcore list.*/
844 new = get_new_element();
849 list_add_tail(&new->list, vc_list);
851 /* Update the program header offset. */
852 phdr_ptr->p_offset = vmcore_off + (paddr - start);
853 vmcore_off = vmcore_off + size;
858 static int __init process_ptload_program_headers_elf32(char *elfptr,
861 struct list_head *vc_list)
864 Elf32_Ehdr *ehdr_ptr;
865 Elf32_Phdr *phdr_ptr;
869 ehdr_ptr = (Elf32_Ehdr *)elfptr;
870 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
872 /* Skip Elf header, program headers and Elf note segment. */
873 vmcore_off = elfsz + elfnotes_sz;
875 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
876 u64 paddr, start, end, size;
878 if (phdr_ptr->p_type != PT_LOAD)
881 paddr = phdr_ptr->p_offset;
882 start = rounddown(paddr, PAGE_SIZE);
883 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
886 /* Add this contiguous chunk of memory to vmcore list.*/
887 new = get_new_element();
892 list_add_tail(&new->list, vc_list);
894 /* Update the program header offset */
895 phdr_ptr->p_offset = vmcore_off + (paddr - start);
896 vmcore_off = vmcore_off + size;
901 /* Sets offset fields of vmcore elements. */
902 static void __init set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
903 struct list_head *vc_list)
908 /* Skip Elf header, program headers and Elf note segment. */
909 vmcore_off = elfsz + elfnotes_sz;
911 list_for_each_entry(m, vc_list, list) {
912 m->offset = vmcore_off;
913 vmcore_off += m->size;
917 static void free_elfcorebuf(void)
919 free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
925 static int __init parse_crash_elf64_headers(void)
931 addr = elfcorehdr_addr;
933 /* Read Elf header */
934 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
938 /* Do some basic Verification. */
939 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
940 (ehdr.e_type != ET_CORE) ||
941 !vmcore_elf64_check_arch(&ehdr) ||
942 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
943 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
944 ehdr.e_version != EV_CURRENT ||
945 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
946 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
948 pr_warn("Warning: Core image elf header is not sane\n");
952 /* Read in all elf headers. */
953 elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
954 ehdr.e_phnum * sizeof(Elf64_Phdr);
955 elfcorebuf_sz = elfcorebuf_sz_orig;
956 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
957 get_order(elfcorebuf_sz_orig));
960 addr = elfcorehdr_addr;
961 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
965 /* Merge all PT_NOTE headers into one. */
966 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
967 &elfnotes_buf, &elfnotes_sz);
970 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
971 elfnotes_sz, &vmcore_list);
974 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
981 static int __init parse_crash_elf32_headers(void)
987 addr = elfcorehdr_addr;
989 /* Read Elf header */
990 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
994 /* Do some basic Verification. */
995 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
996 (ehdr.e_type != ET_CORE) ||
997 !elf_check_arch(&ehdr) ||
998 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
999 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1000 ehdr.e_version != EV_CURRENT ||
1001 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1002 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1003 ehdr.e_phnum == 0) {
1004 pr_warn("Warning: Core image elf header is not sane\n");
1008 /* Read in all elf headers. */
1009 elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1010 elfcorebuf_sz = elfcorebuf_sz_orig;
1011 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1012 get_order(elfcorebuf_sz_orig));
1015 addr = elfcorehdr_addr;
1016 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1020 /* Merge all PT_NOTE headers into one. */
1021 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1022 &elfnotes_buf, &elfnotes_sz);
1025 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1026 elfnotes_sz, &vmcore_list);
1029 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1036 static int __init parse_crash_elf_headers(void)
1038 unsigned char e_ident[EI_NIDENT];
1042 addr = elfcorehdr_addr;
1043 rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1046 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1047 pr_warn("Warning: Core image elf header not found\n");
1051 if (e_ident[EI_CLASS] == ELFCLASS64) {
1052 rc = parse_crash_elf64_headers();
1055 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
1056 rc = parse_crash_elf32_headers();
1060 pr_warn("Warning: Core image elf header is not sane\n");
1064 /* Determine vmcore size. */
1065 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1071 /* Init function for vmcore module. */
1072 static int __init vmcore_init(void)
1076 /* Allow architectures to allocate ELF header in 2nd kernel */
1077 rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1081 * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1082 * then capture the dump.
1084 if (!(is_vmcore_usable()))
1086 rc = parse_crash_elf_headers();
1088 pr_warn("Kdump: vmcore not initialized\n");
1091 elfcorehdr_free(elfcorehdr_addr);
1092 elfcorehdr_addr = ELFCORE_ADDR_ERR;
1094 proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &proc_vmcore_operations);
1096 proc_vmcore->size = vmcore_size;
1099 fs_initcall(vmcore_init);
1101 /* Cleanup function for vmcore module. */
1102 void vmcore_cleanup(void)
1104 struct list_head *pos, *next;
1107 proc_remove(proc_vmcore);
1111 /* clear the vmcore list. */
1112 list_for_each_safe(pos, next, &vmcore_list) {
1115 m = list_entry(pos, struct vmcore, list);
1121 EXPORT_SYMBOL_GPL(vmcore_cleanup);