arch/unicore32/kernel/hibernate.c

   1 /*
   2  *  linux/arch/unicore32/kernel/hibernate.c
   3  *
   4  * Code specific to PKUnity SoC and UniCore ISA
   5  *
   6  *      Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
   7  *      Copyright (C) 2001-2010 Guan Xuetao
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/gfp.h>
  15 #include <linux/suspend.h>
  16 #include <linux/bootmem.h>
  17
  18 #include <asm/page.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/pgalloc.h>
  21 #include <asm/suspend.h>
  22
  23 #include "mach/pm.h"
  24
  25 /* Pointer to the temporary resume page tables */
  26 pgd_t *resume_pg_dir;
  27
  28 struct swsusp_arch_regs swsusp_arch_regs_cpu0;
  29
  30 /*
  31  * Create a middle page table on a resume-safe page and put a pointer to it in
  32  * the given global directory entry.  This only returns the gd entry
  33  * in non-PAE compilation mode, since the middle layer is folded.
  34  */
  35 static pmd_t *resume_one_md_table_init(pgd_t *pgd)
  36 {
  37         pud_t *pud;
  38         pmd_t *pmd_table;
  39
  40         pud = pud_offset(pgd, 0);
  41         pmd_table = pmd_offset(pud, 0);
  42
  43         return pmd_table;
  44 }
  45
  46 /*
  47  * Create a page table on a resume-safe page and place a pointer to it in
  48  * a middle page directory entry.
  49  */
  50 static pte_t *resume_one_page_table_init(pmd_t *pmd)
  51 {
  52         if (pmd_none(*pmd)) {
  53                 pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
  54                 if (!page_table)
  55                         return NULL;
  56
  57                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_KERNEL_TABLE));
  58
  59                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
  60
  61                 return page_table;
  62         }
  63
  64         return pte_offset_kernel(pmd, 0);
  65 }
  66
  67 /*
  68  * This maps the physical memory to kernel virtual address space, a total
  69  * of max_low_pfn pages, by creating page tables starting from address
  70  * PAGE_OFFSET.  The page tables are allocated out of resume-safe pages.
  71  */
  72 static int resume_physical_mapping_init(pgd_t *pgd_base)
  73 {
  74         unsigned long pfn;
  75         pgd_t *pgd;
  76         pmd_t *pmd;
  77         pte_t *pte;
  78         int pgd_idx, pmd_idx;
  79
  80         pgd_idx = pgd_index(PAGE_OFFSET);
  81         pgd = pgd_base + pgd_idx;
  82         pfn = 0;
  83
  84         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
  85                 pmd = resume_one_md_table_init(pgd);
  86                 if (!pmd)
  87                         return -ENOMEM;
  88
  89                 if (pfn >= max_low_pfn)
  90                         continue;
  91
  92                 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
  93                         pte_t *max_pte;
  94
  95                         if (pfn >= max_low_pfn)
  96                                 break;
  97
  98                         /* Map with normal page tables.
  99                          * NOTE: We can mark everything as executable here
 100                          */
 101                         pte = resume_one_page_table_init(pmd);
 102                         if (!pte)
 103                                 return -ENOMEM;
 104
 105                         max_pte = pte + PTRS_PER_PTE;
 106                         for (; pte < max_pte; pte++, pfn++) {
 107                                 if (pfn >= max_low_pfn)
 108                                         break;
 109
 110                                 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
 111                         }
 112                 }
 113         }
 114
 115         return 0;
 116 }
 117
 118 static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
 119 {
 120 }
 121
 122 int swsusp_arch_resume(void)
 123 {
 124         int error;
 125
 126         resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
 127         if (!resume_pg_dir)
 128                 return -ENOMEM;
 129
 130         resume_init_first_level_page_table(resume_pg_dir);
 131         error = resume_physical_mapping_init(resume_pg_dir);
 132         if (error)
 133                 return error;
 134
 135         /* We have got enough memory and from now on we cannot recover */
 136         restore_image(resume_pg_dir, restore_pblist);
 137         return 0;
 138 }
 139
 140 /*
 141  *      pfn_is_nosave - check if given pfn is in the 'nosave' section
 142  */
 143
 144 int pfn_is_nosave(unsigned long pfn)
 145 {
 146         unsigned long begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
 147         unsigned long end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
 148
 149         return (pfn >= begin_pfn) && (pfn < end_pfn);
 150 }
 151
 152 void save_processor_state(void)
 153 {
 154 }
 155
 156 void restore_processor_state(void)
 157 {
 158         local_flush_tlb_all();
 159 }