summaryrefslogtreecommitdiff
path: root/arch/unicore32/kernel/hibernate.c
blob: 3a216fd14b99fa02c62c56ae04dfdee94bf934e8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/arch/unicore32/kernel/hibernate.c
 *
 * Code specific to PKUnity SoC and UniCore ISA
 *
 *	Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
 *	Copyright (C) 2001-2010 Guan Xuetao
 */

#include <linux/gfp.h>
#include <linux/suspend.h>
#include <linux/memblock.h>

#include <asm/page.h>
#include <linux/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/suspend.h>

#include "mach/pm.h"

/* Pointer to the temporary resume page tables */
pgd_t *resume_pg_dir;

struct swsusp_arch_regs swsusp_arch_regs_cpu0;

/*
 * Create a middle page table on a resume-safe page and put a pointer to it in
 * the given global directory entry.  This only returns the gd entry
 * in non-PAE compilation mode, since the middle layer is folded.
 */
static pmd_t *resume_one_md_table_init(pgd_t *pgd)
{
	pud_t *pud;
	p4d_t *p4d;
	pmd_t *pmd_table;

	p4d = p4d_offset(pgd, 0);
	pud = pud_offset(p4d, 0);
	pmd_table = pmd_offset(pud, 0);

	return pmd_table;
}

/*
 * Create a page table on a resume-safe page and place a pointer to it in
 * a middle page directory entry.
 */
static pte_t *resume_one_page_table_init(pmd_t *pmd)
{
	if (pmd_none(*pmd)) {
		pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
		if (!page_table)
			return NULL;

		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_KERNEL_TABLE));

		BUG_ON(page_table != pte_offset_kernel(pmd, 0));

		return page_table;
	}

	return pte_offset_kernel(pmd, 0);
}

/*
 * This maps the physical memory to kernel virtual address space, a total
 * of max_low_pfn pages, by creating page tables starting from address
 * PAGE_OFFSET.  The page tables are allocated out of resume-safe pages.
 */
static int resume_physical_mapping_init(pgd_t *pgd_base)
{
	unsigned long pfn;
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte;
	int pgd_idx, pmd_idx;

	pgd_idx = pgd_index(PAGE_OFFSET);
	pgd = pgd_base + pgd_idx;
	pfn = 0;

	for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
		pmd = resume_one_md_table_init(pgd);
		if (!pmd)
			return -ENOMEM;

		if (pfn >= max_low_pfn)
			continue;

		for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
			pte_t *max_pte;

			if (pfn >= max_low_pfn)
				break;

			/* Map with normal page tables.
			 * NOTE: We can mark everything as executable here
			 */
			pte = resume_one_page_table_init(pmd);
			if (!pte)
				return -ENOMEM;

			max_pte = pte + PTRS_PER_PTE;
			for (; pte < max_pte; pte++, pfn++) {
				if (pfn >= max_low_pfn)
					break;

				set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
			}
		}
	}

	return 0;
}

static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
{
}

int swsusp_arch_resume(void)
{
	int error;

	resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
	if (!resume_pg_dir)
		return -ENOMEM;

	resume_init_first_level_page_table(resume_pg_dir);
	error = resume_physical_mapping_init(resume_pg_dir);
	if (error)
		return error;

	/* We have got enough memory and from now on we cannot recover */
	restore_image(resume_pg_dir, restore_pblist);
	return 0;
}

/*
 *	pfn_is_nosave - check if given pfn is in the 'nosave' section
 */

int pfn_is_nosave(unsigned long pfn)
{
	unsigned long begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
	unsigned long end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;

	return (pfn >= begin_pfn) && (pfn < end_pfn);
}

void save_processor_state(void)
{
}

void restore_processor_state(void)
{
	local_flush_tlb_all();
}