1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Hibernation support for x86-64
4 *
5 * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
6 * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
7 * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
8 */
9
10#include <linux/gfp.h>
11#include <linux/smp.h>
12#include <linux/suspend.h>
13#include <linux/scatterlist.h>
14#include <linux/kdebug.h>
15#include <linux/pgtable.h>
16
17#include <crypto/hash.h>
18
19#include <asm/e820/api.h>
20#include <asm/init.h>
21#include <asm/proto.h>
22#include <asm/page.h>
23#include <asm/mtrr.h>
24#include <asm/sections.h>
25#include <asm/suspend.h>
26#include <asm/tlbflush.h>
27
28static int set_up_temporary_text_mapping(pgd_t *pgd)
29{
30	pmd_t *pmd;
31	pud_t *pud;
32	p4d_t *p4d = NULL;
33	pgprot_t pgtable_prot = __pgprot(_KERNPG_TABLE);
34	pgprot_t pmd_text_prot = __pgprot(__PAGE_KERNEL_LARGE_EXEC);
35
36	/* Filter out unsupported __PAGE_KERNEL* bits: */
37	pgprot_val(pmd_text_prot) &= __default_kernel_pte_mask;
38	pgprot_val(pgtable_prot)  &= __default_kernel_pte_mask;
39
40	/*
41	 * The new mapping only has to cover the page containing the image
42	 * kernel's entry point (jump_address_phys), because the switch over to
43	 * it is carried out by relocated code running from a page allocated
44	 * specifically for this purpose and covered by the identity mapping, so
45	 * the temporary kernel text mapping is only needed for the final jump.
46	 * Moreover, in that mapping the virtual address of the image kernel's
47	 * entry point must be the same as its virtual address in the image
48	 * kernel (restore_jump_address), so the image kernel's
49	 * restore_registers() code doesn't find itself in a different area of
50	 * the virtual address space after switching over to the original page
51	 * tables used by the image kernel.
52	 */
53
54	if (pgtable_l5_enabled()) {
55		p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
56		if (!p4d)
57			return -ENOMEM;
58	}
59
60	pud = (pud_t *)get_safe_page(GFP_ATOMIC);
61	if (!pud)
62		return -ENOMEM;
63
64	pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
65	if (!pmd)
66		return -ENOMEM;
67
68	set_pmd(pmd + pmd_index(restore_jump_address),
69		__pmd((jump_address_phys & PMD_MASK) | pgprot_val(pmd_text_prot)));
70	set_pud(pud + pud_index(restore_jump_address),
71		__pud(__pa(pmd) | pgprot_val(pgtable_prot)));
72	if (p4d) {
73		p4d_t new_p4d = __p4d(__pa(pud) | pgprot_val(pgtable_prot));
74		pgd_t new_pgd = __pgd(__pa(p4d) | pgprot_val(pgtable_prot));
75
76		set_p4d(p4d + p4d_index(restore_jump_address), new_p4d);
77		set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
78	} else {
79		/* No p4d for 4-level paging: point the pgd to the pud page table */
80		pgd_t new_pgd = __pgd(__pa(pud) | pgprot_val(pgtable_prot));
81		set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
82	}
83
84	return 0;
85}
86
87static void *alloc_pgt_page(void *context)
88{
89	return (void *)get_safe_page(GFP_ATOMIC);
90}
91
92static int set_up_temporary_mappings(void)
93{
94	struct x86_mapping_info info = {
95		.alloc_pgt_page	= alloc_pgt_page,
96		.page_flag	= __PAGE_KERNEL_LARGE_EXEC,
97		.offset		= __PAGE_OFFSET,
98	};
99	unsigned long mstart, mend;
100	pgd_t *pgd;
101	int result;
102	int i;
103
104	pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
105	if (!pgd)
106		return -ENOMEM;
107
108	/* Prepare a temporary mapping for the kernel text */
109	result = set_up_temporary_text_mapping(pgd);
110	if (result)
111		return result;
112
113	/* Set up the direct mapping from scratch */
114	for (i = 0; i < nr_pfn_mapped; i++) {
115		mstart = pfn_mapped[i].start << PAGE_SHIFT;
116		mend   = pfn_mapped[i].end << PAGE_SHIFT;
117
118		result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
119		if (result)
120			return result;
121	}
122
123	temp_pgt = __pa(pgd);
124	return 0;
125}
126
127asmlinkage int swsusp_arch_resume(void)
128{
129	int error;
130
131	/* We have got enough memory and from now on we cannot recover */
132	error = set_up_temporary_mappings();
133	if (error)
134		return error;
135
136	error = relocate_restore_code();
137	if (error)
138		return error;
139
140	restore_image();
141	return 0;
142}
143