LXR linux/arch/x86/kernel/head32.c

   1/*
   2 *  linux/arch/i386/kernel/head32.c -- prepare to run common code
   3 *
   4 *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
   5 *  Copyright (C) 2007 Eric Biederman <ebiederm@xmission.com>
   6 */
   7
   8#include <linux/init.h>
   9#include <linux/start_kernel.h>
  10#include <linux/mm.h>
  11#include <linux/memblock.h>
  12
  13#include <asm/setup.h>
  14#include <asm/sections.h>
  15#include <asm/e820/api.h>
  16#include <asm/page.h>
  17#include <asm/apic.h>
  18#include <asm/io_apic.h>
  19#include <asm/bios_ebda.h>
  20#include <asm/tlbflush.h>
  21#include <asm/bootparam_utils.h>
  22
  23static void __init i386_default_early_setup(void)
  24{
  25        /* Initialize 32bit specific setup functions */
  26        x86_init.resources.reserve_resources = i386_reserve_resources;
  27        x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc;
  28}
  29
  30asmlinkage __visible void __init i386_start_kernel(void)
  31{
  32        cr4_init_shadow();
  33        sanitize_boot_params(&boot_params);
  34
  35        x86_early_init_platform_quirks();
  36
  37        /* Call the subarch specific early setup function */
  38        switch (boot_params.hdr.hardware_subarch) {
  39        case X86_SUBARCH_INTEL_MID:
  40                x86_intel_mid_early_setup();
  41                break;
  42        case X86_SUBARCH_CE4100:
  43                x86_ce4100_early_setup();
  44                break;
  45        default:
  46                i386_default_early_setup();
  47                break;
  48        }
  49
  50        start_kernel();
  51}
  52
  53/*
  54 * Initialize page tables.  This creates a PDE and a set of page
  55 * tables, which are located immediately beyond __brk_base.  The variable
  56 * _brk_end is set up to point to the first "safe" location.
  57 * Mappings are created both at virtual address 0 (identity mapping)
  58 * and PAGE_OFFSET for up to _end.
  59 *
  60 * In PAE mode initial_page_table is statically defined to contain
  61 * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
  62 * entries). The identity mapping is handled by pointing two PGD entries
  63 * to the first kernel PMD. Note the upper half of each PMD or PTE are
  64 * always zero at this stage.
  65 */
  66void __init mk_early_pgtbl_32(void)
  67{
  68#ifdef __pa
  69#undef __pa
  70#endif
  71#define __pa(x)  ((unsigned long)(x) - PAGE_OFFSET)
  72        pte_t pte, *ptep;
  73        int i;
  74        unsigned long *ptr;
  75        /* Enough space to fit pagetables for the low memory linear map */
  76        const unsigned long limit = __pa(_end) +
  77                (PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT);
  78#ifdef CONFIG_X86_PAE
  79        pmd_t pl2, *pl2p = (pmd_t *)__pa(initial_pg_pmd);
  80#define SET_PL2(pl2, val)    { (pl2).pmd = (val); }
  81#else
  82        pgd_t pl2, *pl2p = (pgd_t *)__pa(initial_page_table);
  83#define SET_PL2(pl2, val)   { (pl2).pgd = (val); }
  84#endif
  85
  86        ptep = (pte_t *)__pa(__brk_base);
  87        pte.pte = PTE_IDENT_ATTR;
  88
  89        while ((pte.pte & PTE_PFN_MASK) < limit) {
  90
  91                SET_PL2(pl2, (unsigned long)ptep | PDE_IDENT_ATTR);
  92                *pl2p = pl2;
  93#ifndef CONFIG_X86_PAE
  94                /* Kernel PDE entry */
  95                *(pl2p +  ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
  96#endif
  97                for (i = 0; i < PTRS_PER_PTE; i++) {
  98                        *ptep = pte;
  99                        pte.pte += PAGE_SIZE;
 100                        ptep++;
 101                }
 102
 103                pl2p++;
 104        }
 105
 106        ptr = (unsigned long *)__pa(&max_pfn_mapped);
 107        /* Can't use pte_pfn() since it's a call with CONFIG_PARAVIRT */
 108        *ptr = (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
 109
 110        ptr = (unsigned long *)__pa(&_brk_end);
 111        *ptr = (unsigned long)ptep + PAGE_OFFSET;
 112}
 113
 114