arch/x86/kernel/head64.c

   1 /*
   2  *  prepare to run common code
   3  *
   4  *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
   5  */
   6
   7 #include <linux/init.h>
   8 #include <linux/linkage.h>
   9 #include <linux/types.h>
  10 #include <linux/kernel.h>
  11 #include <linux/string.h>
  12 #include <linux/percpu.h>
  13 #include <linux/start_kernel.h>
  14 #include <linux/io.h>
  15 #include <linux/memblock.h>
  16
  17 #include <asm/processor.h>
  18 #include <asm/proto.h>
  19 #include <asm/smp.h>
  20 #include <asm/setup.h>
  21 #include <asm/desc.h>
  22 #include <asm/pgtable.h>
  23 #include <asm/tlbflush.h>
  24 #include <asm/sections.h>
  25 #include <asm/kdebug.h>
  26 #include <asm/e820.h>
  27 #include <asm/bios_ebda.h>
  28 #include <asm/bootparam_utils.h>
  29 #include <asm/microcode.h>
  30 #include <asm/kasan.h>
  31
  32 /*
  33  * Manage page tables very early on.
  34  */
  35 extern pgd_t early_level4_pgt[PTRS_PER_PGD];
  36 extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
  37 static unsigned int __initdata next_early_pgt = 2;
  38 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
  39
  40 /* Wipe all early page tables except for the kernel symbol map */
  41 static void __init reset_early_page_tables(void)
  42 {
  43         memset(early_level4_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1));
  44         next_early_pgt = 0;
  45         write_cr3(__pa_nodebug(early_level4_pgt));
  46 }
  47
  48 /* Create a new PMD entry */
  49 int __init early_make_pgtable(unsigned long address)
  50 {
  51         unsigned long physaddr = address - __PAGE_OFFSET;
  52         pgdval_t pgd, *pgd_p;
  53         pudval_t pud, *pud_p;
  54         pmdval_t pmd, *pmd_p;
  55
  56         /* Invalid address or early pgt is done ?  */
  57         if (physaddr >= MAXMEM || read_cr3() != __pa_nodebug(early_level4_pgt))
  58                 return -1;
  59
  60 again:
  61         pgd_p = &early_level4_pgt[pgd_index(address)].pgd;
  62         pgd = *pgd_p;
  63
  64         /*
  65          * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
  66          * critical -- __PAGE_OFFSET would point us back into the dynamic
  67          * range and we might end up looping forever...
  68          */
  69         if (pgd)
  70                 pud_p = (pudval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
  71         else {
  72                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
  73                         reset_early_page_tables();
  74                         goto again;
  75                 }
  76
  77                 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
  78                 memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
  79                 *pgd_p = (pgdval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
  80         }
  81         pud_p += pud_index(address);
  82         pud = *pud_p;
  83
  84         if (pud)
  85                 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
  86         else {
  87                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
  88                         reset_early_page_tables();
  89                         goto again;
  90                 }
  91
  92                 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
  93                 memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
  94                 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
  95         }
  96         pmd = (physaddr & PMD_MASK) + early_pmd_flags;
  97         pmd_p[pmd_index(address)] = pmd;
  98
  99         return 0;
 100 }
 101
 102 /* Don't add a printk in there. printk relies on the PDA which is not initialized
 103    yet. */
 104 static void __init clear_bss(void)
 105 {
 106         memset(__bss_start, 0,
 107                (unsigned long) __bss_stop - (unsigned long) __bss_start);
 108 }
 109
 110 static unsigned long get_cmd_line_ptr(void)
 111 {
 112         unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
 113
 114         cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
 115
 116         return cmd_line_ptr;
 117 }
 118
 119 static void __init copy_bootdata(char *real_mode_data)
 120 {
 121         char * command_line;
 122         unsigned long cmd_line_ptr;
 123
 124         memcpy(&boot_params, real_mode_data, sizeof boot_params);
 125         sanitize_boot_params(&boot_params);
 126         cmd_line_ptr = get_cmd_line_ptr();
 127         if (cmd_line_ptr) {
 128                 command_line = __va(cmd_line_ptr);
 129                 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 130         }
 131 }
 132
 133 asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
 134 {
 135         int i;
 136
 137         /*
 138          * Build-time sanity checks on the kernel image and module
 139          * area mappings. (these are purely build-time and produce no code)
 140          */
 141         BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
 142         BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
 143         BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
 144         BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
 145         BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
 146         BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
 147         BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
 148                                 (__START_KERNEL & PGDIR_MASK)));
 149         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
 150
 151         cr4_init_shadow();
 152
 153         /* Kill off the identity-map trampoline */
 154         reset_early_page_tables();
 155
 156         clear_bss();
 157
 158         clear_page(init_level4_pgt);
 159
 160         kasan_early_init();
 161
 162         for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
 163                 set_intr_gate(i, early_idt_handler_array[i]);
 164         load_idt((const struct desc_ptr *)&idt_descr);
 165
 166         copy_bootdata(__va(real_mode_data));
 167
 168         /*
 169          * Load microcode early on BSP.
 170          */
 171         load_ucode_bsp();
 172
 173         /* set init_level4_pgt kernel high mapping*/
 174         init_level4_pgt[511] = early_level4_pgt[511];
 175
 176         x86_64_start_reservations(real_mode_data);
 177 }
 178
 179 void __init x86_64_start_reservations(char *real_mode_data)
 180 {
 181         /* version is always not zero if it is copied */
 182         if (!boot_params.hdr.version)
 183                 copy_bootdata(__va(real_mode_data));
 184
 185         reserve_ebda_region();
 186
 187         switch (boot_params.hdr.hardware_subarch) {
 188         case X86_SUBARCH_INTEL_MID:
 189                 x86_intel_mid_early_setup();
 190                 break;
 191         default:
 192                 break;
 193         }
 194
 195         start_kernel();
 196 }