src/cpu/x86/pae/pgtbl.c

   1 #include <console/console.h>
   2 #include <cpu/cpu.h>
   3 #include <cpu/x86/pae.h>
   4 #include <string.h>
   5
   6 static void paging_off(void)
   7 {
   8         __asm__ __volatile__ (
   9                 /* Disable paging */
  10                 "movl   %%cr0, %%eax\n\t"
  11                 "andl   $0x7FFFFFFF, %%eax\n\t"
  12                 "movl   %%eax, %%cr0\n\t"
  13                 /* Disable pae */
  14                 "movl   %%cr4, %%eax\n\t"
  15                 "andl   $0xFFFFFFDF, %%eax\n\t"
  16                 "movl   %%eax, %%cr4\n\t"
  17                 :
  18                 :
  19                 : "eax"
  20                 );
  21 }
  22
  23 static void paging_on(void *pdp)
  24 {
  25         __asm__ __volatile__(
  26                 /* Load the page table address */
  27                 "movl   %0, %%cr3\n\t"
  28                 /* Enable pae */
  29                 "movl   %%cr4, %%eax\n\t"
  30                 "orl    $0x00000020, %%eax\n\t"
  31                 "movl   %%eax, %%cr4\n\t"
  32                 /* Enable paging */
  33                 "movl   %%cr0, %%eax\n\t"
  34                 "orl    $0x80000000, %%eax\n\t"
  35                 "movl   %%eax, %%cr0\n\t"
  36                 :
  37                 : "r" (pdp)
  38                 : "eax"
  39                 );
  40 }
  41
  42 void *map_2M_page(unsigned long page)
  43 {
  44         struct pde {
  45                 uint32_t addr_lo;
  46                 uint32_t addr_hi;
  47         } __attribute__ ((packed));
  48         struct pg_table {
  49                 struct pde pd[2048];
  50                 struct pde pdp[512];
  51         } __attribute__ ((packed));
  52         static struct pg_table pgtbl[CONFIG_MAX_CPUS] __attribute__ ((aligned(4096)));
  53         static unsigned long mapped_window[CONFIG_MAX_CPUS];
  54         unsigned long index;
  55         unsigned long window;
  56         void *result;
  57         int i;
  58         index = cpu_index();
  59         if ((index < 0) || (index >= CONFIG_MAX_CPUS)) {
  60                 return MAPPING_ERROR;
  61         }
  62         window = page >> 10;
  63         if (window != mapped_window[index]) {
  64                 paging_off();
  65                 if (window > 1) {
  66                         struct pde *pd, *pdp;
  67                         /* Point the page directory pointers at the page directories */
  68                         memset(&pgtbl[index].pdp, 0, sizeof(pgtbl[index].pdp));
  69                         pd = pgtbl[index].pd;
  70                         pdp = pgtbl[index].pdp;
  71                         pdp[0].addr_lo = ((uint32_t)&pd[512*0])|1;
  72                         pdp[1].addr_lo = ((uint32_t)&pd[512*1])|1;
  73                         pdp[2].addr_lo = ((uint32_t)&pd[512*2])|1;
  74                         pdp[3].addr_lo = ((uint32_t)&pd[512*3])|1;
  75                         /* The first half of the page table is identity mapped */
  76                         for(i = 0; i < 1024; i++) {
  77                                 pd[i].addr_lo = ((i & 0x3ff) << 21)| 0xE3;
  78                                 pd[i].addr_hi = 0;
  79                         }
  80                         /* The second half of the page table holds the mapped page */
  81                         for(i = 1024; i < 2048; i++) {
  82                                 pd[i].addr_lo = ((window & 1) << 31) | ((i & 0x3ff) << 21) | 0xE3;
  83                                 pd[i].addr_hi = (window >> 1);
  84                         }
  85                         paging_on(pdp);
  86                 }
  87                 mapped_window[index] = window;
  88         }
  89         if (window == 0) {
  90                 result = (void *)(page << 21);
  91         } else {
  92                 result = (void *)(0x80000000 | ((page & 0x3ff) << 21));
  93         }
  94         return result;
  95 }