git.zerfleddert.de Git - ms2-kexec/blob - idmap.c

   1 #include <linux/kernel.h>
   2
   3 #include "tlbflush.h"
   4 #include <asm/cputype.h>
   5 #include <asm/pgalloc.h>
   6 #include <asm/pgtable.h>
   7
   8 static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
   9         unsigned long prot)
  10 {
  11         pmd_t *pmd = pmd_offset(pud, addr);
  12
  13         addr = (addr & PMD_MASK) | prot;
  14         pmd[0] = __pmd(addr);
  15         addr += SECTION_SIZE;
  16         pmd[1] = __pmd(addr);
  17         flush_pmd_entry(pmd);
  18 }
  19
  20 static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
  21         unsigned long prot)
  22 {
  23         pud_t *pud = pud_offset(pgd, addr);
  24         unsigned long next;
  25
  26         do {
  27                 next = pud_addr_end(addr, end);
  28                 idmap_add_pmd(pud, addr, next, prot);
  29         } while (pud++, addr = next, addr != end);
  30 }
  31
  32 void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
  33 {
  34         unsigned long prot, next;
  35
  36         prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE;
  37 #if 0
  38         if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
  39                 prot |= PMD_BIT4;
  40 #endif
  41
  42         pgd += pgd_index(addr);
  43         do {
  44                 next = pgd_addr_end(addr, end);
  45                 idmap_add_pud(pgd, addr, next, prot);
  46         } while (pgd++, addr = next, addr != end);
  47 }
  48
  49 #ifdef CONFIG_SMP
  50 static void idmap_del_pmd(pud_t *pud, unsigned long addr, unsigned long end)
  51 {
  52         pmd_t *pmd = pmd_offset(pud, addr);
  53         pmd_clear(pmd);
  54 }
  55
  56 static void idmap_del_pud(pgd_t *pgd, unsigned long addr, unsigned long end)
  57 {
  58         pud_t *pud = pud_offset(pgd, addr);
  59         unsigned long next;
  60
  61         do {
  62                 next = pud_addr_end(addr, end);
  63                 idmap_del_pmd(pud, addr, next);
  64         } while (pud++, addr = next, addr != end);
  65 }
  66
  67 void identity_mapping_del(pgd_t *pgd, unsigned long addr, unsigned long end)
  68 {
  69         unsigned long next;
  70
  71         pgd += pgd_index(addr);
  72         do {
  73                 next = pgd_addr_end(addr, end);
  74                 idmap_del_pud(pgd, addr, next);
  75         } while (pgd++, addr = next, addr != end);
  76 }
  77 #endif
  78
  79 /*
  80  * In order to soft-boot, we need to insert a 1:1 mapping in place of
  81  * the user-mode pages.  This will then ensure that we have predictable
  82  * results when turning the mmu off
  83  */
  84 void setup_mm_for_reboot(char mode)
  85 {
  86         /*
  87          * We need to access to user-mode page tables here. For kernel threads
  88          * we don't have any user-mode mappings so we use the context that we
  89          * "borrowed".
  90          */
  91         identity_mapping_add(current->active_mm->pgd, 0, TASK_SIZE);
  92         my_local_flush_tlb_all();
  93 }