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/uaccess.h>
12#include <linux/io.h>
 
13
14static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
15				  unsigned long offset, int userbuf,
16				  bool encrypted)
17{
18	void  *vaddr;
19
20	if (!csize)
21		return 0;
22
23	if (encrypted)
24		vaddr = (__force void *)ioremap_encrypted(pfn << PAGE_SHIFT, PAGE_SIZE);
25	else
26		vaddr = (__force void *)ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
27
28	if (!vaddr)
29		return -ENOMEM;
30
31	if (userbuf) {
32		if (copy_to_user((void __user *)buf, vaddr + offset, csize)) {
33			iounmap((void __iomem *)vaddr);
34			return -EFAULT;
35		}
36	} else
37		memcpy(buf, vaddr + offset, csize);
38
39	set_iounmap_nonlazy();
40	iounmap((void __iomem *)vaddr);
41	return csize;
42}
43
44/**
45 * copy_oldmem_page - copy one page of memory
46 * @pfn: page frame number to be copied
47 * @buf: target memory address for the copy; this can be in kernel address
48 *	space or user address space (see @userbuf)
49 * @csize: number of bytes to copy
50 * @offset: offset in bytes into the page (based on pfn) to begin the copy
51 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
52 *	otherwise @buf is in kernel address space, use memcpy().
53 *
54 * Copy a page from the old kernel's memory. For this page, there is no pte
55 * mapped in the current kernel. We stitch up a pte, similar to kmap_atomic.
56 */
57ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
58			 unsigned long offset, int userbuf)
59{
60	return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, false);
61}
62
63/**
64 * copy_oldmem_page_encrypted - same as copy_oldmem_page() above but ioremap the
65 * memory with the encryption mask set to accommodate kdump on SME-enabled
66 * machines.
67 */
68ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
69				   unsigned long offset, int userbuf)
70{
71	return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true);
72}
73
74ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
75{
76	return read_from_oldmem(buf, count, ppos, 0, sev_active());
 
 
 
 
 
 
77}

 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}