1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Memory preserving reboot related code.
4 *
5 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
6 * Copyright (C) IBM Corporation, 2004. All rights reserved
7 */
8
9 #include <linux/errno.h>
10 #include <linux/crash_dump.h>
11 #include <linux/uio.h>
12 #include <linux/io.h>
13 #include <linux/cc_platform.h>
14
15 static ssize_t __copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
16 size_t csize, unsigned long offset,
17 bool encrypted)
18 {
19 void *vaddr;
20
21 if (!csize)
22 return 0;
23
24 if (encrypted)
25 vaddr = (__force void *)ioremap_encrypted(pfn << PAGE_SHIFT, PAGE_SIZE);
26 else
27 vaddr = (__force void *)ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
28
29 if (!vaddr)
30 return -ENOMEM;
31
32 csize = copy_to_iter(vaddr + offset, csize, iter);
33
34 iounmap((void __iomem *)vaddr);
35 return csize;
36 }
37
38 ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize,
39 unsigned long offset)
40 {
41 return __copy_oldmem_page(iter, pfn, csize, offset, false);
42 }
43
44 /*
45 * copy_oldmem_page_encrypted - same as copy_oldmem_page() above but ioremap the
46 * memory with the encryption mask set to accommodate kdump on SME-enabled
47 * machines.
48 */
49 ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
50 size_t csize, unsigned long offset)
51 {
52 return __copy_oldmem_page(iter, pfn, csize, offset, true);
53 }
54
55 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
56 {
57 struct kvec kvec = { .iov_base = buf, .iov_len = count };
58 struct iov_iter iter;
59
60 iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
61
62 return read_from_oldmem(&iter, count, ppos,
63 cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT));
64 }
65
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