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Diffstat (limited to '')
| -rw-r--r-- | arch/ia64/kernel/crash_dump.c | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/arch/ia64/kernel/crash_dump.c b/arch/ia64/kernel/crash_dump.c new file mode 100644 index 000000000..0ed3c3dee --- /dev/null +++ b/arch/ia64/kernel/crash_dump.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * kernel/crash_dump.c - Memory preserving reboot related code. + * + * Created by: Simon Horman <horms@verge.net.au> + * Original code moved from kernel/crash.c + * Original code comment copied from the i386 version of this file + */ + +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/crash_dump.h> + +#include <asm/page.h> +#include <linux/uaccess.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. + * + * Calling copy_to_user() in atomic context is not desirable. Hence first + * copying the data to a pre-allocated kernel page and then copying to user + * space in non-atomic context. + */ +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 = __va(pfn<<PAGE_SHIFT); + if (userbuf) { + if (copy_to_user(buf, (vaddr + offset), csize)) { + return -EFAULT; + } + } else + memcpy(buf, (vaddr + offset), csize); + return csize; +} + |