1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/unicore32/kernel/hibernate.c
4 *
5 * Code specific to PKUnity SoC and UniCore ISA
6 *
7 * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
8 * Copyright (C) 2001-2010 Guan Xuetao
9 */
10
11 #include <linux/gfp.h>
12 #include <linux/suspend.h>
13 #include <linux/memblock.h>
14
15 #include <asm/page.h>
16 #include <asm/pgtable.h>
17 #include <asm/pgalloc.h>
18 #include <asm/sections.h>
19 #include <asm/suspend.h>
20
21 #include "mach/pm.h"
22
23 /* Pointer to the temporary resume page tables */
24 pgd_t *resume_pg_dir;
25
26 struct swsusp_arch_regs swsusp_arch_regs_cpu0;
27
28 /*
29 * Create a middle page table on a resume-safe page and put a pointer to it in
30 * the given global directory entry. This only returns the gd entry
31 * in non-PAE compilation mode, since the middle layer is folded.
32 */
resume_one_md_table_init(pgd_t * pgd)33 static pmd_t *resume_one_md_table_init(pgd_t *pgd)
34 {
35 pud_t *pud;
36 pmd_t *pmd_table;
37
38 pud = pud_offset(pgd, 0);
39 pmd_table = pmd_offset(pud, 0);
40
41 return pmd_table;
42 }
43
44 /*
45 * Create a page table on a resume-safe page and place a pointer to it in
46 * a middle page directory entry.
47 */
resume_one_page_table_init(pmd_t * pmd)48 static pte_t *resume_one_page_table_init(pmd_t *pmd)
49 {
50 if (pmd_none(*pmd)) {
51 pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
52 if (!page_table)
53 return NULL;
54
55 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_KERNEL_TABLE));
56
57 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
58
59 return page_table;
60 }
61
62 return pte_offset_kernel(pmd, 0);
63 }
64
65 /*
66 * This maps the physical memory to kernel virtual address space, a total
67 * of max_low_pfn pages, by creating page tables starting from address
68 * PAGE_OFFSET. The page tables are allocated out of resume-safe pages.
69 */
resume_physical_mapping_init(pgd_t * pgd_base)70 static int resume_physical_mapping_init(pgd_t *pgd_base)
71 {
72 unsigned long pfn;
73 pgd_t *pgd;
74 pmd_t *pmd;
75 pte_t *pte;
76 int pgd_idx, pmd_idx;
77
78 pgd_idx = pgd_index(PAGE_OFFSET);
79 pgd = pgd_base + pgd_idx;
80 pfn = 0;
81
82 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
83 pmd = resume_one_md_table_init(pgd);
84 if (!pmd)
85 return -ENOMEM;
86
87 if (pfn >= max_low_pfn)
88 continue;
89
90 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
91 pte_t *max_pte;
92
93 if (pfn >= max_low_pfn)
94 break;
95
96 /* Map with normal page tables.
97 * NOTE: We can mark everything as executable here
98 */
99 pte = resume_one_page_table_init(pmd);
100 if (!pte)
101 return -ENOMEM;
102
103 max_pte = pte + PTRS_PER_PTE;
104 for (; pte < max_pte; pte++, pfn++) {
105 if (pfn >= max_low_pfn)
106 break;
107
108 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
109 }
110 }
111 }
112
113 return 0;
114 }
115
resume_init_first_level_page_table(pgd_t * pg_dir)116 static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
117 {
118 }
119
swsusp_arch_resume(void)120 int swsusp_arch_resume(void)
121 {
122 int error;
123
124 resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
125 if (!resume_pg_dir)
126 return -ENOMEM;
127
128 resume_init_first_level_page_table(resume_pg_dir);
129 error = resume_physical_mapping_init(resume_pg_dir);
130 if (error)
131 return error;
132
133 /* We have got enough memory and from now on we cannot recover */
134 restore_image(resume_pg_dir, restore_pblist);
135 return 0;
136 }
137
138 /*
139 * pfn_is_nosave - check if given pfn is in the 'nosave' section
140 */
141
pfn_is_nosave(unsigned long pfn)142 int pfn_is_nosave(unsigned long pfn)
143 {
144 unsigned long begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
145 unsigned long end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
146
147 return (pfn >= begin_pfn) && (pfn < end_pfn);
148 }
149
save_processor_state(void)150 void save_processor_state(void)
151 {
152 }
153
restore_processor_state(void)154 void restore_processor_state(void)
155 {
156 local_flush_tlb_all();
157 }
158