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/sections.h>
  22 #include <asm/suspend.h>
  23
  24 #include "mach/pm.h"
  25
  26 /* Pointer to the temporary resume page tables */
  27 pgd_t *resume_pg_dir;
  28
  29 struct swsusp_arch_regs swsusp_arch_regs_cpu0;
  30
  31 /*
  32  * Create a middle page table on a resume-safe page and put a pointer to it in
  33  * the given global directory entry.  This only returns the gd entry
  34  * in non-PAE compilation mode, since the middle layer is folded.
  35  */
  36 static pmd_t *resume_one_md_table_init(pgd_t *pgd)
  37 {
  38         pud_t *pud;
  39         pmd_t *pmd_table;
  40
  41         pud = pud_offset(pgd, 0);
  42         pmd_table = pmd_offset(pud, 0);
  43
  44         return pmd_table;
  45 }
  46
  47 /*
  48  * Create a page table on a resume-safe page and place a pointer to it in
  49  * a middle page directory entry.
  50  */
  51 static pte_t *resume_one_page_table_init(pmd_t *pmd)
  52 {
  53         if (pmd_none(*pmd)) {
  54                 pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
  55                 if (!page_table)
  56                         return NULL;
  57
  58                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_KERNEL_TABLE));
  59
  60                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
  61
  62                 return page_table;
  63         }
  64
  65         return pte_offset_kernel(pmd, 0);
  66 }
  67
  68 /*
  69  * This maps the physical memory to kernel virtual address space, a total
  70  * of max_low_pfn pages, by creating page tables starting from address
  71  * PAGE_OFFSET.  The page tables are allocated out of resume-safe pages.
  72  */
  73 static int resume_physical_mapping_init(pgd_t *pgd_base)
  74 {
  75         unsigned long pfn;
  76         pgd_t *pgd;
  77         pmd_t *pmd;
  78         pte_t *pte;
  79         int pgd_idx, pmd_idx;
  80
  81         pgd_idx = pgd_index(PAGE_OFFSET);
  82         pgd = pgd_base + pgd_idx;
  83         pfn = 0;
  84
  85         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
  86                 pmd = resume_one_md_table_init(pgd);
  87                 if (!pmd)
  88                         return -ENOMEM;
  89
  90                 if (pfn >= max_low_pfn)
  91                         continue;
  92
  93                 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
  94                         pte_t *max_pte;
  95
  96                         if (pfn >= max_low_pfn)
  97                                 break;
  98
  99                         /* Map with normal page tables.
 100                          * NOTE: We can mark everything as executable here
 101                          */
 102                         pte = resume_one_page_table_init(pmd);
 103                         if (!pte)
 104                                 return -ENOMEM;
 105
 106                         max_pte = pte + PTRS_PER_PTE;
 107                         for (; pte < max_pte; pte++, pfn++) {
 108                                 if (pfn >= max_low_pfn)
 109                                         break;
 110
 111                                 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
 112                         }
 113                 }
 114         }
 115
 116         return 0;
 117 }
 118
 119 static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
 120 {
 121 }
 122
 123 int swsusp_arch_resume(void)
 124 {
 125         int error;
 126
 127         resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
 128         if (!resume_pg_dir)
 129                 return -ENOMEM;
 130
 131         resume_init_first_level_page_table(resume_pg_dir);
 132         error = resume_physical_mapping_init(resume_pg_dir);
 133         if (error)
 134                 return error;
 135
 136         /* We have got enough memory and from now on we cannot recover */
 137         restore_image(resume_pg_dir, restore_pblist);
 138         return 0;
 139 }
 140
 141 /*
 142  *      pfn_is_nosave - check if given pfn is in the 'nosave' section
 143  */
 144
 145 int pfn_is_nosave(unsigned long pfn)
 146 {
 147         unsigned long begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
 148         unsigned long end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
 149
 150         return (pfn >= begin_pfn) && (pfn < end_pfn);
 151 }
 152
 153 void save_processor_state(void)
 154 {
 155 }
 156
 157 void restore_processor_state(void)
 158 {
 159         local_flush_tlb_all();
 160 }