68 строки
1.9 KiB
C
68 строки
1.9 KiB
C
/*
|
|
* crash_dump.c - Memory preserving reboot related code.
|
|
*
|
|
* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
|
|
* Copyright (C) IBM Corporation, 2004. All rights reserved
|
|
*/
|
|
#include <linux/errno.h>
|
|
#include <linux/crash_dump.h>
|
|
#include <linux/io.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
/* Stores the physical address of elf header of crash image. */
|
|
unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
|
|
|
|
/*
|
|
* Note: elfcorehdr_addr is not just limited to vmcore. It is also used by
|
|
* is_kdump_kernel() to determine if we are booting after a panic. Hence
|
|
* ifdef it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE.
|
|
*
|
|
* elfcorehdr= specifies the location of elf core header
|
|
* stored by the crashed kernel.
|
|
*/
|
|
static int __init parse_elfcorehdr(char *arg)
|
|
{
|
|
if (!arg)
|
|
return -EINVAL;
|
|
|
|
elfcorehdr_addr = memparse(arg, &arg);
|
|
|
|
return 0;
|
|
}
|
|
early_param("elfcorehdr", parse_elfcorehdr);
|
|
|
|
/**
|
|
* copy_oldmem_page - copy one page from "oldmem"
|
|
* @pfn: page frame number to be copied
|
|
* @buf: target memory address for the copy; this can be in kernel address
|
|
* space or user address space (see @userbuf)
|
|
* @csize: number of bytes to copy
|
|
* @offset: offset in bytes into the page (based on pfn) to begin the copy
|
|
* @userbuf: if set, @buf is in user address space, use copy_to_user(),
|
|
* otherwise @buf is in kernel address space, use memcpy().
|
|
*
|
|
* Copy a page from "oldmem". For this page, there is no pte mapped
|
|
* in the current kernel. We stitch up a pte, similar to kmap_atomic.
|
|
*/
|
|
ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
|
|
size_t csize, unsigned long offset, int userbuf)
|
|
{
|
|
void *vaddr;
|
|
|
|
if (!csize)
|
|
return 0;
|
|
|
|
vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
|
|
|
|
if (userbuf) {
|
|
if (copy_to_user(buf, (vaddr + offset), csize)) {
|
|
iounmap(vaddr);
|
|
return -EFAULT;
|
|
}
|
|
} else
|
|
memcpy(buf, (vaddr + offset), csize);
|
|
|
|
iounmap(vaddr);
|
|
return csize;
|
|
}
|