blob: f7cdb3b457aadc7f0f8951323dc507827211be75 [file] [log] [blame]
Vivek Goyal4ae362b2006-01-09 20:51:50 -08001/*
Dave Jones835c34a2007-10-12 21:10:53 -04002 * Memory preserving reboot related code.
Vivek Goyal4ae362b2006-01-09 20:51:50 -08003 *
4 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
5 * Copyright (C) IBM Corporation, 2004. All rights reserved
6 */
7
8#include <linux/errno.h>
9#include <linux/highmem.h>
10#include <linux/crash_dump.h>
11
12#include <asm/uaccess.h>
13
14static void *kdump_buf_page;
15
Vivek Goyal57cac4d2008-10-18 20:28:25 -070016/* Stores the physical address of elf header of crash image. */
17unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
18
Vivek Goyal4ae362b2006-01-09 20:51:50 -080019/**
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().
28 *
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.
31 *
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.
35 */
36ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
37 size_t csize, unsigned long offset, int userbuf)
38{
39 void *vaddr;
40
41 if (!csize)
42 return 0;
43
44 vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
45
46 if (!userbuf) {
47 memcpy(buf, (vaddr + offset), csize);
48 kunmap_atomic(vaddr, KM_PTE0);
49 } else {
50 if (!kdump_buf_page) {
51 printk(KERN_WARNING "Kdump: Kdump buffer page not"
52 " allocated\n");
Fernando Luis Vázquez Cao22124c92007-10-18 23:39:14 -070053 kunmap_atomic(vaddr, KM_PTE0);
Vivek Goyal4ae362b2006-01-09 20:51:50 -080054 return -EFAULT;
55 }
56 copy_page(kdump_buf_page, vaddr);
57 kunmap_atomic(vaddr, KM_PTE0);
58 if (copy_to_user(buf, (kdump_buf_page + offset), csize))
59 return -EFAULT;
60 }
61
62 return csize;
63}
64
65static int __init kdump_buf_page_init(void)
66{
67 int ret = 0;
68
69 kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
70 if (!kdump_buf_page) {
71 printk(KERN_WARNING "Kdump: Failed to allocate kdump buffer"
72 " page\n");
73 ret = -ENOMEM;
74 }
75
76 return ret;
77}
78arch_initcall(kdump_buf_page_init);