linux/arch/x86/kernel/crash_dump_32.c
Vivek Goyal 57cac4d188 kdump: make elfcorehdr_addr independent of CONFIG_PROC_VMCORE
o elfcorehdr_addr is used by not only the code under CONFIG_PROC_VMCORE
  but also by the code which is not inside CONFIG_PROC_VMCORE.  For
  example, is_kdump_kernel() is used by powerpc code to determine if
  kernel is booting after a panic then use previous kernel's TCE table.
  So even if CONFIG_PROC_VMCORE is not set in second kernel, one should be
  able to correctly determine that we are booting after a panic and setup
  calgary iommu accordingly.

o So remove the assumption that elfcorehdr_addr is under
  CONFIG_PROC_VMCORE.

o Move definition of elfcorehdr_addr to arch dependent crash files.
  (Unfortunately crash dump does not have an arch independent file
  otherwise that would have been the best place).

o kexec.c is not the right place as one can Have CRASH_DUMP enabled in
  second kernel without KEXEC being enabled.

o I don't see sh setup code parsing the command line for
  elfcorehdr_addr.  I am wondering how does vmcore interface work on sh.
  Anyway, I am atleast defining elfcoredhr_addr so that compilation is not
  broken on sh.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Simon Horman <horms@verge.net.au>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:39 -07:00

78 lines
2.1 KiB
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/highmem.h>
#include <linux/crash_dump.h>
#include <asm/uaccess.h>
static void *kdump_buf_page;
/* Stores the physical address of elf header of crash image. */
unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
/**
* 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.
*
* Calling copy_to_user() in atomic context is not desirable. Hence first
* copying the data to a pre-allocated kernel page and then copying to user
* space in non-atomic context.
*/
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 = kmap_atomic_pfn(pfn, KM_PTE0);
if (!userbuf) {
memcpy(buf, (vaddr + offset), csize);
kunmap_atomic(vaddr, KM_PTE0);
} else {
if (!kdump_buf_page) {
printk(KERN_WARNING "Kdump: Kdump buffer page not"
" allocated\n");
kunmap_atomic(vaddr, KM_PTE0);
return -EFAULT;
}
copy_page(kdump_buf_page, vaddr);
kunmap_atomic(vaddr, KM_PTE0);
if (copy_to_user(buf, (kdump_buf_page + offset), csize))
return -EFAULT;
}
return csize;
}
static int __init kdump_buf_page_init(void)
{
int ret = 0;
kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!kdump_buf_page) {
printk(KERN_WARNING "Kdump: Failed to allocate kdump buffer"
" page\n");
ret = -ENOMEM;
}
return ret;
}
arch_initcall(kdump_buf_page_init);