]>
git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - arch/x86/kernel/crash_dump_32.c
2 * Memory preserving reboot related code.
4 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
5 * Copyright (C) IBM Corporation, 2004. All rights reserved
8 #include <linux/errno.h>
9 #include <linux/highmem.h>
10 #include <linux/crash_dump.h>
12 #include <asm/uaccess.h>
14 static void *kdump_buf_page
;
16 /* Stores the physical address of elf header of crash image. */
17 unsigned long long elfcorehdr_addr
= ELFCORE_ADDR_MAX
;
20 * copy_oldmem_page - copy one page from "oldmem"
21 * @pfn: page frame number to be copied
22 * @buf: target memory address for the copy; this can be in kernel address
23 * space or user address space (see @userbuf)
24 * @csize: number of bytes to copy
25 * @offset: offset in bytes into the page (based on pfn) to begin the copy
26 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
27 * otherwise @buf is in kernel address space, use memcpy().
29 * Copy a page from "oldmem". For this page, there is no pte mapped
30 * in the current kernel. We stitch up a pte, similar to kmap_atomic.
32 * Calling copy_to_user() in atomic context is not desirable. Hence first
33 * copying the data to a pre-allocated kernel page and then copying to user
34 * space in non-atomic context.
36 ssize_t
copy_oldmem_page(unsigned long pfn
, char *buf
,
37 size_t csize
, unsigned long offset
, int userbuf
)
44 vaddr
= kmap_atomic_pfn(pfn
, KM_PTE0
);
47 memcpy(buf
, (vaddr
+ offset
), csize
);
48 kunmap_atomic(vaddr
, KM_PTE0
);
50 if (!kdump_buf_page
) {
51 printk(KERN_WARNING
"Kdump: Kdump buffer page not"
53 kunmap_atomic(vaddr
, KM_PTE0
);
56 copy_page(kdump_buf_page
, vaddr
);
57 kunmap_atomic(vaddr
, KM_PTE0
);
58 if (copy_to_user(buf
, (kdump_buf_page
+ offset
), csize
))
65 static int __init
kdump_buf_page_init(void)
69 kdump_buf_page
= kmalloc(PAGE_SIZE
, GFP_KERNEL
);
70 if (!kdump_buf_page
) {
71 printk(KERN_WARNING
"Kdump: Failed to allocate kdump buffer"
78 arch_initcall(kdump_buf_page_init
);