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[PATCH] kdump: read previous kernel's memory

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- Moving the crash_dump.c file to arch dependent part as kmap_atomic_pfn is
  specific to i386 and highmem may not exist in other archs.

- Use ioremap for x86_64 to map the previous kernel memory.

- In copy_oldmem_page(), we now directly copy to the user/kernel buffer and
  avoid the unneccesary copy to a kmalloc'd page.

Signed-off-by: Rachita Kothiyal <rachita@in.ibm.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Vivek Goyal 2006-01-09 20:51:50 -08:00 • committed by Linus Torvalds
parent ec9ce0dbaa
commit 4ae362be50
6 changed files with 88 additions and 27 deletions
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64
kernel/crash_dump.c
View file

@ -1,64 +0,0 @@
/*
* kernel/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/smp_lock.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/crash_dump.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/kexec.h>
/* Stores the physical address of elf header of crash image. */
unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
#ifndef HAVE_ARCH_COPY_OLDMEM_PAGE
/**
* 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 *page, *vaddr;
if (!csize)
return 0;
page = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!page)
return -ENOMEM;
vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
copy_page(page, vaddr);
kunmap_atomic(vaddr, KM_PTE0);
if (userbuf) {
if (copy_to_user(buf, (page + offset), csize)) {
kfree(page);
return -EFAULT;
}
} else {
memcpy(buf, (page + offset), csize);
}
kfree(page);
return csize;
}
#endif