From 4ae362be509306eafa6441603686d33fefe321c1 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Mon, 9 Jan 2006 20:51:50 -0800 Subject: [PATCH] kdump: read previous kernel's memory - Moving the crash_dump.c file to arch dependent part as kmap_atomic_pfn is specific to i386 and highmem may not exist in other archs. - Use ioremap for x86_64 to map the previous kernel memory. - In copy_oldmem_page(), we now directly copy to the user/kernel buffer and avoid the unneccesary copy to a kmalloc'd page. Signed-off-by: Rachita Kothiyal Signed-off-by: Vivek Goyal Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/crash_dump.c | 47 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 arch/x86_64/kernel/crash_dump.c (limited to 'arch/x86_64/kernel/crash_dump.c') diff --git a/arch/x86_64/kernel/crash_dump.c b/arch/x86_64/kernel/crash_dump.c new file mode 100644 index 00000000000..942deac4d43 --- /dev/null +++ b/arch/x86_64/kernel/crash_dump.c @@ -0,0 +1,47 @@ +/* + * 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 +#include + +#include +#include + +/** + * 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 (userbuf) { + if (copy_to_user(buf, (vaddr + offset), csize)) { + iounmap(vaddr); + return -EFAULT; + } + } else + memcpy(buf, (vaddr + offset), csize); + + iounmap(vaddr); + return csize; +} -- cgit v1.2.3