/* * 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> /* 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. */ 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; }