1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0
29a163ed8SThomas Gleixner /*
3835c34a1SDave Jones * Memory preserving reboot related code.
49a163ed8SThomas Gleixner *
59a163ed8SThomas Gleixner * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
69a163ed8SThomas Gleixner * Copyright (C) IBM Corporation, 2004. All rights reserved
79a163ed8SThomas Gleixner */
89a163ed8SThomas Gleixner
95a0e3ad6STejun Heo #include <linux/slab.h>
109a163ed8SThomas Gleixner #include <linux/errno.h>
119a163ed8SThomas Gleixner #include <linux/highmem.h>
129a163ed8SThomas Gleixner #include <linux/crash_dump.h>
13*5d8de293SMatthew Wilcox (Oracle) #include <linux/uio.h>
149a163ed8SThomas Gleixner
is_crashed_pfn_valid(unsigned long pfn)1572ed7de7SJiri Slaby static inline bool is_crashed_pfn_valid(unsigned long pfn)
1672ed7de7SJiri Slaby {
1772ed7de7SJiri Slaby #ifndef CONFIG_X86_PAE
1872ed7de7SJiri Slaby /*
1972ed7de7SJiri Slaby * non-PAE kdump kernel executed from a PAE one will crop high pte
2072ed7de7SJiri Slaby * bits and poke unwanted space counting again from address 0, we
2172ed7de7SJiri Slaby * don't want that. pte must fit into unsigned long. In fact the
2272ed7de7SJiri Slaby * test checks high 12 bits for being zero (pfn will be shifted left
2372ed7de7SJiri Slaby * by PAGE_SHIFT).
2472ed7de7SJiri Slaby */
2572ed7de7SJiri Slaby return pte_pfn(pfn_pte(pfn, __pgprot(0))) == pfn;
2672ed7de7SJiri Slaby #else
2772ed7de7SJiri Slaby return true;
2872ed7de7SJiri Slaby #endif
2972ed7de7SJiri Slaby }
3072ed7de7SJiri Slaby
copy_oldmem_page(struct iov_iter * iter,unsigned long pfn,size_t csize,unsigned long offset)31*5d8de293SMatthew Wilcox (Oracle) ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize,
32*5d8de293SMatthew Wilcox (Oracle) unsigned long offset)
339a163ed8SThomas Gleixner {
349a163ed8SThomas Gleixner void *vaddr;
359a163ed8SThomas Gleixner
369a163ed8SThomas Gleixner if (!csize)
379a163ed8SThomas Gleixner return 0;
389a163ed8SThomas Gleixner
3972ed7de7SJiri Slaby if (!is_crashed_pfn_valid(pfn))
4072ed7de7SJiri Slaby return -EFAULT;
4172ed7de7SJiri Slaby
427e015a27SThomas Gleixner vaddr = kmap_local_pfn(pfn);
43*5d8de293SMatthew Wilcox (Oracle) csize = copy_to_iter(vaddr + offset, csize, iter);
447e015a27SThomas Gleixner kunmap_local(vaddr);
459a163ed8SThomas Gleixner
469a163ed8SThomas Gleixner return csize;
479a163ed8SThomas Gleixner }
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