LXR linux/arch/powerpc/mm/init

   1/*
   2 *  PowerPC version
   3 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   4 *
   5 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
   6 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
   7 *    Copyright (C) 1996 Paul Mackerras
   8 *  PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
   9 *
  10 *  Derived from "arch/i386/mm/init.c"
  11 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  12 *
  13 *  This program is free software; you can redistribute it and/or
  14 *  modify it under the terms of the GNU General Public License
  15 *  as published by the Free Software Foundation; either version
  16 *  2 of the License, or (at your option) any later version.
  17 *
  18 */
  19
  20#include <linux/module.h>
  21#include <linux/sched.h>
  22#include <linux/kernel.h>
  23#include <linux/errno.h>
  24#include <linux/string.h>
  25#include <linux/types.h>
  26#include <linux/mm.h>
  27#include <linux/stddef.h>
  28#include <linux/init.h>
  29#include <linux/bootmem.h>
  30#include <linux/highmem.h>
  31#include <linux/initrd.h>
  32#include <linux/pagemap.h>
  33#include <linux/memblock.h>
  34#include <linux/gfp.h>
  35#include <linux/slab.h>
  36#include <linux/hugetlb.h>
  37
  38#include <asm/pgalloc.h>
  39#include <asm/prom.h>
  40#include <asm/io.h>
  41#include <asm/pgtable.h>
  42#include <asm/mmu.h>
  43#include <asm/smp.h>
  44#include <asm/machdep.h>
  45#include <asm/btext.h>
  46#include <asm/tlb.h>
  47#include <asm/sections.h>
  48#include <asm/hugetlb.h>
  49
  50#include "mmu_decl.h"
  51
  52#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
  53/* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
  54#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
  55#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
  56#endif
  57#endif
  58#define MAX_LOW_MEM     CONFIG_LOWMEM_SIZE
  59
  60phys_addr_t total_memory;
  61phys_addr_t total_lowmem;
  62
  63phys_addr_t memstart_addr = (phys_addr_t)~0ull;
  64EXPORT_SYMBOL(memstart_addr);
  65phys_addr_t kernstart_addr;
  66EXPORT_SYMBOL(kernstart_addr);
  67
  68#ifdef CONFIG_RELOCATABLE_PPC32
  69/* Used in __va()/__pa() */
  70long long virt_phys_offset;
  71EXPORT_SYMBOL(virt_phys_offset);
  72#endif
  73
  74phys_addr_t lowmem_end_addr;
  75
  76int boot_mapsize;
  77#ifdef CONFIG_PPC_PMAC
  78unsigned long agp_special_page;
  79EXPORT_SYMBOL(agp_special_page);
  80#endif
  81
  82void MMU_init(void);
  83
  84/* XXX should be in current.h  -- paulus */
  85extern struct task_struct *current_set[NR_CPUS];
  86
  87/*
  88 * this tells the system to map all of ram with the segregs
  89 * (i.e. page tables) instead of the bats.
  90 * -- Cort
  91 */
  92int __map_without_bats;
  93int __map_without_ltlbs;
  94
  95/*
  96 * This tells the system to allow ioremapping memory marked as reserved.
  97 */
  98int __allow_ioremap_reserved;
  99
 100/* max amount of low RAM to map in */
 101unsigned long __max_low_memory = MAX_LOW_MEM;
 102
 103/*
 104 * Check for command-line options that affect what MMU_init will do.
 105 */
 106void MMU_setup(void)
 107{
 108        /* Check for nobats option (used in mapin_ram). */
 109        if (strstr(cmd_line, "nobats")) {
 110                __map_without_bats = 1;
 111        }
 112
 113        if (strstr(cmd_line, "noltlbs")) {
 114                __map_without_ltlbs = 1;
 115        }
 116#ifdef CONFIG_DEBUG_PAGEALLOC
 117        __map_without_bats = 1;
 118        __map_without_ltlbs = 1;
 119#endif
 120}
 121
 122/*
 123 * MMU_init sets up the basic memory mappings for the kernel,
 124 * including both RAM and possibly some I/O regions,
 125 * and sets up the page tables and the MMU hardware ready to go.
 126 */
 127void __init MMU_init(void)
 128{
 129        if (ppc_md.progress)
 130                ppc_md.progress("MMU:enter", 0x111);
 131
 132        /* parse args from command line */
 133        MMU_setup();
 134
 135        /*
 136         * Reserve gigantic pages for hugetlb.  This MUST occur before
 137         * lowmem_end_addr is initialized below.
 138         */
 139        reserve_hugetlb_gpages();
 140
 141        if (memblock.memory.cnt > 1) {
 142#ifndef CONFIG_WII
 143                memblock_enforce_memory_limit(memblock.memory.regions[0].size);
 144                printk(KERN_WARNING "Only using first contiguous memory region");
 145#else
 146                wii_memory_fixups();
 147#endif
 148        }
 149
 150        total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
 151        lowmem_end_addr = memstart_addr + total_lowmem;
 152
 153#ifdef CONFIG_FSL_BOOKE
 154        /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
 155         * entries, so we need to adjust lowmem to match the amount we can map
 156         * in the fixed entries */
 157        adjust_total_lowmem();
 158#endif /* CONFIG_FSL_BOOKE */
 159
 160        if (total_lowmem > __max_low_memory) {
 161                total_lowmem = __max_low_memory;
 162                lowmem_end_addr = memstart_addr + total_lowmem;
 163#ifndef CONFIG_HIGHMEM
 164                total_memory = total_lowmem;
 165                memblock_enforce_memory_limit(total_lowmem);
 166#endif /* CONFIG_HIGHMEM */
 167        }
 168
 169        /* Initialize the MMU hardware */
 170        if (ppc_md.progress)
 171                ppc_md.progress("MMU:hw init", 0x300);
 172        MMU_init_hw();
 173
 174        /* Map in all of RAM starting at KERNELBASE */
 175        if (ppc_md.progress)
 176                ppc_md.progress("MMU:mapin", 0x301);
 177        mapin_ram();
 178
 179        /* Initialize early top-down ioremap allocator */
 180        ioremap_bot = IOREMAP_TOP;
 181
 182        /* Map in I/O resources */
 183        if (ppc_md.progress)
 184                ppc_md.progress("MMU:setio", 0x302);
 185
 186        if (ppc_md.progress)
 187                ppc_md.progress("MMU:exit", 0x211);
 188
 189        /* From now on, btext is no longer BAT mapped if it was at all */
 190#ifdef CONFIG_BOOTX_TEXT
 191        btext_unmap();
 192#endif
 193
 194        /* Shortly after that, the entire linear mapping will be available */
 195        memblock_set_current_limit(lowmem_end_addr);
 196}
 197
 198/* This is only called until mem_init is done. */
 199void __init *early_get_page(void)
 200{
 201        if (init_bootmem_done)
 202                return alloc_bootmem_pages(PAGE_SIZE);
 203        else
 204                return __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
 205}
 206
 207#ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
 208void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 209                                phys_addr_t first_memblock_size)
 210{
 211        /* We don't currently support the first MEMBLOCK not mapping 0
 212         * physical on those processors
 213         */
 214        BUG_ON(first_memblock_base != 0);
 215
 216        /* 8xx can only access 8MB at the moment */
 217        memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000));
 218}
 219#endif /* CONFIG_8xx */
 220