diff options
Diffstat (limited to 'arch/x86/kernel/crash_dump_32.c')
-rw-r--r-- | arch/x86/kernel/crash_dump_32.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_32.c new file mode 100644 index 0000000000..5f4ae5476e --- /dev/null +++ b/arch/x86/kernel/crash_dump_32.c @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Memory preserving reboot related code. + * + * Created by: Hariprasad Nellitheertha (hari@in.ibm.com) + * Copyright (C) IBM Corporation, 2004. All rights reserved + */ + +#include <linux/slab.h> +#include <linux/errno.h> +#include <linux/highmem.h> +#include <linux/crash_dump.h> +#include <linux/uio.h> + +static inline bool is_crashed_pfn_valid(unsigned long pfn) +{ +#ifndef CONFIG_X86_PAE + /* + * non-PAE kdump kernel executed from a PAE one will crop high pte + * bits and poke unwanted space counting again from address 0, we + * don't want that. pte must fit into unsigned long. In fact the + * test checks high 12 bits for being zero (pfn will be shifted left + * by PAGE_SHIFT). + */ + return pte_pfn(pfn_pte(pfn, __pgprot(0))) == pfn; +#else + return true; +#endif +} + +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize, + unsigned long offset) +{ + void *vaddr; + + if (!csize) + return 0; + + if (!is_crashed_pfn_valid(pfn)) + return -EFAULT; + + vaddr = kmap_local_pfn(pfn); + csize = copy_to_iter(vaddr + offset, csize, iter); + kunmap_local(vaddr); + + return csize; +} |