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
15static 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
38ssize_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 */
49ssize_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
55ssize_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