| /* |
| * 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 <asm/uaccess.h> |
| #include <asm/io.h> |
| |
| /** |
| * 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 (!vaddr) |
| return -ENOMEM; |
| |
| if (userbuf) { |
| if (copy_to_user(buf, vaddr + offset, csize)) { |
| iounmap(vaddr); |
| return -EFAULT; |
| } |
| } else |
| memcpy(buf, vaddr + offset, csize); |
| |
| iounmap(vaddr); |
| return csize; |
| } |