diff options
Diffstat (limited to 'kernel/crash_dump.c')
-rw-r--r-- | kernel/crash_dump.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/kernel/crash_dump.c b/kernel/crash_dump.c new file mode 100644 index 00000000000..5a1e6d5d203 --- /dev/null +++ b/kernel/crash_dump.c @@ -0,0 +1,49 @@ +/* + * 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> + +/* + * 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; +} |