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DEFINITIONS
This source file includes following definitions.
- read_from_oldmem
- map_offset_to_paddr
- read_vmcore
- get_new_element
- get_vmcore_size_elf64
- get_vmcore_size_elf32
- merge_note_headers_elf64
- merge_note_headers_elf32
- process_ptload_program_headers_elf64
- process_ptload_program_headers_elf32
- set_vmcore_list_offsets_elf64
- set_vmcore_list_offsets_elf32
- parse_crash_elf64_headers
- parse_crash_elf32_headers
- parse_crash_elf_headers
- vmcore_init
/*
* fs/proc/vmcore.c Interface for accessing the crash
* dump from the system's previous life.
* Heavily borrowed from fs/proc/kcore.c
* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
* Copyright (C) IBM Corporation, 2004. All rights reserved
*
*/
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/user.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/highmem.h>
#include <linux/bootmem.h>
#include <linux/init.h>
#include <linux/crash_dump.h>
#include <linux/list.h>
#include <asm/uaccess.h>
#include <asm/io.h>
/* List representing chunks of contiguous memory areas and their offsets in
* vmcore file.
*/
static LIST_HEAD(vmcore_list);
/* Stores the pointer to the buffer containing kernel elf core headers. */
static char *elfcorebuf;
static size_t elfcorebuf_sz;
/* Total size of vmcore file. */
static u64 vmcore_size;
/* Stores the physical address of elf header of crash image. */
unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
struct proc_dir_entry *proc_vmcore = NULL;
/* Reads a page from the oldmem device from given offset. */
static ssize_t read_from_oldmem(char *buf, size_t count,
u64 *ppos, int userbuf)
{
unsigned long pfn, offset;
size_t nr_bytes;
ssize_t read = 0, tmp;
if (!count)
return 0;
offset = (unsigned long)(*ppos % PAGE_SIZE);
pfn = (unsigned long)(*ppos / PAGE_SIZE);
if (pfn > saved_max_pfn)
return -EINVAL;
do {
if (count > (PAGE_SIZE - offset))
nr_bytes = PAGE_SIZE - offset;
else
nr_bytes = count;
tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf);
if (tmp < 0)
return tmp;
*ppos += nr_bytes;
count -= nr_bytes;
buf += nr_bytes;
read += nr_bytes;
++pfn;
offset = 0;
} while (count);
return read;
}
/* Maps vmcore file offset to respective physical address in memroy. */
static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,
struct vmcore **m_ptr)
{
struct vmcore *m;
u64 paddr;
list_for_each_entry(m, vc_list, list) {
u64 start, end;
start = m->offset;
end = m->offset + m->size - 1;
if (offset >= start && offset <= end) {
paddr = m->paddr + offset - start;
*m_ptr = m;
return paddr;
}
}
*m_ptr = NULL;
return 0;
}
/* Read from the ELF header and then the crash dump. On error, negative value is
* returned otherwise number of bytes read are returned.
*/
static ssize_t read_vmcore(struct file *file, char __user *buffer,
size_t buflen, loff_t *fpos)
{
ssize_t acc = 0, tmp;
size_t tsz;
u64 start, nr_bytes;
struct vmcore *curr_m = NULL;
if (buflen == 0 || *fpos >= vmcore_size)
return 0;
/* trim buflen to not go beyond EOF */
if (buflen > vmcore_size - *fpos)
buflen = vmcore_size - *fpos;
/* Read ELF core header */
if (*fpos < elfcorebuf_sz) {
tsz = elfcorebuf_sz - *fpos;
if (buflen < tsz)
tsz = buflen;
if (copy_to_user(buffer, elfcorebuf + *fpos, tsz))
return -EFAULT;
buflen -= tsz;
*fpos += tsz;
buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
if (buflen == 0)
return acc;
}
start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
if (!curr_m)
return -EINVAL;
if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
tsz = buflen;
/* Calculate left bytes in current memory segment. */
nr_bytes = (curr_m->size - (start - curr_m->paddr));
if (tsz > nr_bytes)
tsz = nr_bytes;
while (buflen) {
tmp = read_from_oldmem(buffer, tsz, &start, 1);
if (tmp < 0)
return tmp;
buflen -= tsz;
*fpos += tsz;
buffer += tsz;
acc += tsz;
if (start >= (curr_m->paddr + curr_m->size)) {
if (curr_m->list.next == &vmcore_list)
return acc; /*EOF*/
curr_m = list_entry(curr_m->list.next,
struct vmcore, list);
start = curr_m->paddr;
}
if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
tsz = buflen;
/* Calculate left bytes in current memory segment. */
nr_bytes = (curr_m->size - (start - curr_m->paddr));
if (tsz > nr_bytes)
tsz = nr_bytes;
}
return acc;
}
const struct file_operations proc_vmcore_operations = {
.read = read_vmcore,
};
static struct vmcore* __init get_new_element(void)
{
struct vmcore *p;
p = kmalloc(sizeof(*p), GFP_KERNEL);
if (p)
memset(p, 0, sizeof(*p));
return p;
}
static u64 __init get_vmcore_size_elf64(char *elfptr)
{
int i;
u64 size;
Elf64_Ehdr *ehdr_ptr;
Elf64_Phdr *phdr_ptr;
ehdr_ptr = (Elf64_Ehdr *)elfptr;
phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
for (i = 0; i < ehdr_ptr->e_phnum; i++) {
size += phdr_ptr->p_memsz;
phdr_ptr++;
}
return size;
}
static u64 __init get_vmcore_size_elf32(char *elfptr)
{
int i;
u64 size;
Elf32_Ehdr *ehdr_ptr;
Elf32_Phdr *phdr_ptr;
ehdr_ptr = (Elf32_Ehdr *)elfptr;
phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
for (i = 0; i < ehdr_ptr->e_phnum; i++) {
size += phdr_ptr->p_memsz;
phdr_ptr++;
}
return size;
}
/* Merges all the PT_NOTE headers into one. */
static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
struct list_head *vc_list)
{
int i, nr_ptnote=0, rc=0;
char *tmp;
Elf64_Ehdr *ehdr_ptr;
Elf64_Phdr phdr, *phdr_ptr;
Elf64_Nhdr *nhdr_ptr;
u64 phdr_sz = 0, note_off;
ehdr_ptr = (Elf64_Ehdr *)elfptr;
phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
int j;
void *notes_section;
struct vmcore *new;
u64 offset, max_sz, sz, real_sz = 0;
if (phdr_ptr->p_type != PT_NOTE)
continue;
nr_ptnote++;
max_sz = phdr_ptr->p_memsz;
offset = phdr_ptr->p_offset;
notes_section = kmalloc(max_sz, GFP_KERNEL);
if (!notes_section)
return -ENOMEM;
rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
if (rc < 0) {
kfree(notes_section);
return rc;
}
nhdr_ptr = notes_section;
for (j = 0; j < max_sz; j += sz) {
if (nhdr_ptr->n_namesz == 0)
break;
sz = sizeof(Elf64_Nhdr) +
((nhdr_ptr->n_namesz + 3) & ~3) +
((nhdr_ptr->n_descsz + 3) & ~3);
real_sz += sz;
nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
}
/* Add this contiguous chunk of notes section to vmcore list.*/
new = get_new_element();
if (!new) {
kfree(notes_section);
return -ENOMEM;
}
new->paddr = phdr_ptr->p_offset;
new->size = real_sz;
list_add_tail(&new->list, vc_list);
phdr_sz += real_sz;
kfree(notes_section);
}
/* Prepare merged PT_NOTE program header. */
phdr.p_type = PT_NOTE;
phdr.p_flags = 0;
note_off = sizeof(Elf64_Ehdr) +
(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
phdr.p_offset = note_off;
phdr.p_vaddr = phdr.p_paddr = 0;
phdr.p_filesz = phdr.p_memsz = phdr_sz;
phdr.p_align = 0;
/* Add merged PT_NOTE program header*/
tmp = elfptr + sizeof(Elf64_Ehdr);
memcpy(tmp, &phdr, sizeof(phdr));
tmp += sizeof(phdr);
/* Remove unwanted PT_NOTE program headers. */
i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
*elfsz = *elfsz - i;
memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
/* Modify e_phnum to reflect merged headers. */
ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
return 0;
}
/* Merges all the PT_NOTE headers into one. */
static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
struct list_head *vc_list)
{
int i, nr_ptnote=0, rc=0;
char *tmp;
Elf32_Ehdr *ehdr_ptr;
Elf32_Phdr phdr, *phdr_ptr;
Elf32_Nhdr *nhdr_ptr;
u64 phdr_sz = 0, note_off;
ehdr_ptr = (Elf32_Ehdr *)elfptr;
phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
int j;
void *notes_section;
struct vmcore *new;
u64 offset, max_sz, sz, real_sz = 0;
if (phdr_ptr->p_type != PT_NOTE)
continue;
nr_ptnote++;
max_sz = phdr_ptr->p_memsz;
offset = phdr_ptr->p_offset;
notes_section = kmalloc(max_sz, GFP_KERNEL);
if (!notes_section)
return -ENOMEM;
rc = read_from_oldmem(notes_section, max_sz, &offset, 0);
if (rc < 0) {
kfree(notes_section);
return rc;
}
nhdr_ptr = notes_section;
for (j = 0; j < max_sz; j += sz) {
if (nhdr_ptr->n_namesz == 0)
break;
sz = sizeof(Elf32_Nhdr) +
((nhdr_ptr->n_namesz + 3) & ~3) +
((nhdr_ptr->n_descsz + 3) & ~3);
real_sz += sz;
nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
}
/* Add this contiguous chunk of notes section to vmcore list.*/
new = get_new_element();
if (!new) {
kfree(notes_section);
return -ENOMEM;
}
new->paddr = phdr_ptr->p_offset;
new->size = real_sz;
list_add_tail(&new->list, vc_list);
phdr_sz += real_sz;
kfree(notes_section);
}
/* Prepare merged PT_NOTE program header. */
phdr.p_type = PT_NOTE;
phdr.p_flags = 0;
note_off = sizeof(Elf32_Ehdr) +
(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
phdr.p_offset = note_off;
phdr.p_vaddr = phdr.p_paddr = 0;
phdr.p_filesz = phdr.p_memsz = phdr_sz;
phdr.p_align = 0;
/* Add merged PT_NOTE program header*/
tmp = elfptr + sizeof(Elf32_Ehdr);
memcpy(tmp, &phdr, sizeof(phdr));
tmp += sizeof(phdr);
/* Remove unwanted PT_NOTE program headers. */
i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
*elfsz = *elfsz - i;
memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
/* Modify e_phnum to reflect merged headers. */
ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
return 0;
}
/* Add memory chunks represented by program headers to vmcore list. Also update
* the new offset fields of exported program headers. */
static int __init process_ptload_program_headers_elf64(char *elfptr,
size_t elfsz,
struct list_head *vc_list)
{
int i;
Elf64_Ehdr *ehdr_ptr;
Elf64_Phdr *phdr_ptr;
loff_t vmcore_off;
struct vmcore *new;
ehdr_ptr = (Elf64_Ehdr *)elfptr;
phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
/* First program header is PT_NOTE header. */
vmcore_off = sizeof(Elf64_Ehdr) +
(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
phdr_ptr->p_memsz; /* Note sections */
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
if (phdr_ptr->p_type != PT_LOAD)
continue;
/* Add this contiguous chunk of memory to vmcore list.*/
new = get_new_element();
if (!new)
return -ENOMEM;
new->paddr = phdr_ptr->p_offset;
new->size = phdr_ptr->p_memsz;
list_add_tail(&new->list, vc_list);
/* Update the program header offset. */
phdr_ptr->p_offset = vmcore_off;
vmcore_off = vmcore_off + phdr_ptr->p_memsz;
}
return 0;
}
static int __init process_ptload_program_headers_elf32(char *elfptr,
size_t elfsz,
struct list_head *vc_list)
{
int i;
Elf32_Ehdr *ehdr_ptr;
Elf32_Phdr *phdr_ptr;
loff_t vmcore_off;
struct vmcore *new;
ehdr_ptr = (Elf32_Ehdr *)elfptr;
phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
/* First program header is PT_NOTE header. */
vmcore_off = sizeof(Elf32_Ehdr) +
(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
phdr_ptr->p_memsz; /* Note sections */
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
if (phdr_ptr->p_type != PT_LOAD)
continue;
/* Add this contiguous chunk of memory to vmcore list.*/
new = get_new_element();
if (!new)
return -ENOMEM;
new->paddr = phdr_ptr->p_offset;
new->size = phdr_ptr->p_memsz;
list_add_tail(&new->list, vc_list);
/* Update the program header offset */
phdr_ptr->p_offset = vmcore_off;
vmcore_off = vmcore_off + phdr_ptr->p_memsz;
}
return 0;
}
/* Sets offset fields of vmcore elements. */
static void __init set_vmcore_list_offsets_elf64(char *elfptr,
struct list_head *vc_list)
{
loff_t vmcore_off;
Elf64_Ehdr *ehdr_ptr;
struct vmcore *m;
ehdr_ptr = (Elf64_Ehdr *)elfptr;
/* Skip Elf header and program headers. */
vmcore_off = sizeof(Elf64_Ehdr) +
(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
list_for_each_entry(m, vc_list, list) {
m->offset = vmcore_off;
vmcore_off += m->size;
}
}
/* Sets offset fields of vmcore elements. */
static void __init set_vmcore_list_offsets_elf32(char *elfptr,
struct list_head *vc_list)
{
loff_t vmcore_off;
Elf32_Ehdr *ehdr_ptr;
struct vmcore *m;
ehdr_ptr = (Elf32_Ehdr *)elfptr;
/* Skip Elf header and program headers. */
vmcore_off = sizeof(Elf32_Ehdr) +
(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
list_for_each_entry(m, vc_list, list) {
m->offset = vmcore_off;
vmcore_off += m->size;
}
}
static int __init parse_crash_elf64_headers(void)
{
int rc=0;
Elf64_Ehdr ehdr;
u64 addr;
addr = elfcorehdr_addr;
/* Read Elf header */
rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
if (rc < 0)
return rc;
/* Do some basic Verification. */
if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
(ehdr.e_type != ET_CORE) ||
!vmcore_elf_check_arch(&ehdr) ||
ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
ehdr.e_version != EV_CURRENT ||
ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
ehdr.e_phnum == 0) {
printk(KERN_WARNING "Warning: Core image elf header is not"
"sane\n");
return -EINVAL;
}
/* Read in all elf headers. */
elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
if (!elfcorebuf)
return -ENOMEM;
addr = elfcorehdr_addr;
rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
if (rc < 0) {
kfree(elfcorebuf);
return rc;
}
/* Merge all PT_NOTE headers into one. */
rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
if (rc) {
kfree(elfcorebuf);
return rc;
}
rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
&vmcore_list);
if (rc) {
kfree(elfcorebuf);
return rc;
}
set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
return 0;
}
static int __init parse_crash_elf32_headers(void)
{
int rc=0;
Elf32_Ehdr ehdr;
u64 addr;
addr = elfcorehdr_addr;
/* Read Elf header */
rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
if (rc < 0)
return rc;
/* Do some basic Verification. */
if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
(ehdr.e_type != ET_CORE) ||
!elf_check_arch(&ehdr) ||
ehdr.e_ident[EI_CLASS] != ELFCLASS32||
ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
ehdr.e_version != EV_CURRENT ||
ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
ehdr.e_phnum == 0) {
printk(KERN_WARNING "Warning: Core image elf header is not"
"sane\n");
return -EINVAL;
}
/* Read in all elf headers. */
elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
if (!elfcorebuf)
return -ENOMEM;
addr = elfcorehdr_addr;
rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
if (rc < 0) {
kfree(elfcorebuf);
return rc;
}
/* Merge all PT_NOTE headers into one. */
rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
if (rc) {
kfree(elfcorebuf);
return rc;
}
rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
&vmcore_list);
if (rc) {
kfree(elfcorebuf);
return rc;
}
set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
return 0;
}
static int __init parse_crash_elf_headers(void)
{
unsigned char e_ident[EI_NIDENT];
u64 addr;
int rc=0;
addr = elfcorehdr_addr;
rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
if (rc < 0)
return rc;
if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
printk(KERN_WARNING "Warning: Core image elf header"
" not found\n");
return -EINVAL;
}
if (e_ident[EI_CLASS] == ELFCLASS64) {
rc = parse_crash_elf64_headers();
if (rc)
return rc;
/* Determine vmcore size. */
vmcore_size = get_vmcore_size_elf64(elfcorebuf);
} else if (e_ident[EI_CLASS] == ELFCLASS32) {
rc = parse_crash_elf32_headers();
if (rc)
return rc;
/* Determine vmcore size. */
vmcore_size = get_vmcore_size_elf32(elfcorebuf);
} else {
printk(KERN_WARNING "Warning: Core image elf header is not"
" sane\n");
return -EINVAL;
}
return 0;
}
/* Init function for vmcore module. */
static int __init vmcore_init(void)
{
int rc = 0;
/* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
if (!(elfcorehdr_addr < ELFCORE_ADDR_MAX))
return rc;
rc = parse_crash_elf_headers();
if (rc) {
printk(KERN_WARNING "Kdump: vmcore not initialized\n");
return rc;
}
/* Initialize /proc/vmcore size if proc is already up. */
if (proc_vmcore)
proc_vmcore->size = vmcore_size;
return 0;
}
module_init(vmcore_init)