arch/powerpc/mm/init_32.c

   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/highmem.h>
  30 #include <linux/initrd.h>
  31 #include <linux/pagemap.h>
  32 #include <linux/memblock.h>
  33 #include <linux/gfp.h>
  34 #include <linux/slab.h>
  35 #include <linux/hugetlb.h>
  36
  37 #include <asm/pgalloc.h>
  38 #include <asm/prom.h>
  39 #include <asm/io.h>
  40 #include <asm/pgtable.h>
  41 #include <asm/mmu.h>
  42 #include <asm/smp.h>
  43 #include <asm/machdep.h>
  44 #include <asm/btext.h>
  45 #include <asm/tlb.h>
  46 #include <asm/sections.h>
  47 #include <asm/hugetlb.h>
  48
  49 #include "mmu_decl.h"
  50
  51 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
  52 /* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
  53 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
  54 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START"
  55 #endif
  56 #endif
  57 #define MAX_LOW_MEM     CONFIG_LOWMEM_SIZE
  58
  59 phys_addr_t total_memory;
  60 phys_addr_t total_lowmem;
  61
  62 phys_addr_t memstart_addr = (phys_addr_t)~0ull;
  63 EXPORT_SYMBOL(memstart_addr);
  64 phys_addr_t kernstart_addr;
  65 EXPORT_SYMBOL(kernstart_addr);
  66
  67 #ifdef CONFIG_RELOCATABLE_PPC32
  68 /* Used in __va()/__pa() */
  69 long long virt_phys_offset;
  70 EXPORT_SYMBOL(virt_phys_offset);
  71 #endif
  72
  73 phys_addr_t lowmem_end_addr;
  74
  75 int boot_mapsize;
  76 #ifdef CONFIG_PPC_PMAC
  77 unsigned long agp_special_page;
  78 EXPORT_SYMBOL(agp_special_page);
  79 #endif
  80
  81 void MMU_init(void);
  82
  83 /* XXX should be in current.h  -- paulus */
  84 extern struct task_struct *current_set[NR_CPUS];
  85
  86 /*
  87  * this tells the system to map all of ram with the segregs
  88  * (i.e. page tables) instead of the bats.
  89  * -- Cort
  90  */
  91 int __map_without_bats;
  92 int __map_without_ltlbs;
  93
  94 /*
  95  * This tells the system to allow ioremapping memory marked as reserved.
  96  */
  97 int __allow_ioremap_reserved;
  98
  99 /* max amount of low RAM to map in */
 100 unsigned long __max_low_memory = MAX_LOW_MEM;
 101
 102 /*
 103  * Check for command-line options that affect what MMU_init will do.
 104  */
 105 void __init MMU_setup(void)
 106 {
 107         /* Check for nobats option (used in mapin_ram). */
 108         if (strstr(boot_command_line, "nobats")) {
 109                 __map_without_bats = 1;
 110         }
 111
 112         if (strstr(boot_command_line, "noltlbs")) {
 113                 __map_without_ltlbs = 1;
 114         }
 115         if (debug_pagealloc_enabled()) {
 116                 __map_without_bats = 1;
 117                 __map_without_ltlbs = 1;
 118         }
 119 }
 120
 121 /*
 122  * MMU_init sets up the basic memory mappings for the kernel,
 123  * including both RAM and possibly some I/O regions,
 124  * and sets up the page tables and the MMU hardware ready to go.
 125  */
 126 void __init MMU_init(void)
 127 {
 128         if (ppc_md.progress)
 129                 ppc_md.progress("MMU:enter", 0x111);
 130
 131         /* parse args from command line */
 132         MMU_setup();
 133
 134         /*
 135          * Reserve gigantic pages for hugetlb.  This MUST occur before
 136          * lowmem_end_addr is initialized below.
 137          */
 138         reserve_hugetlb_gpages();
 139
 140         if (memblock.memory.cnt > 1) {
 141 #ifndef CONFIG_WII
 142                 memblock_enforce_memory_limit(memblock.memory.regions[0].size);
 143                 printk(KERN_WARNING "Only using first contiguous memory region");
 144 #else
 145                 wii_memory_fixups();
 146 #endif
 147         }
 148
 149         total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
 150         lowmem_end_addr = memstart_addr + total_lowmem;
 151
 152 #ifdef CONFIG_FSL_BOOKE
 153         /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
 154          * entries, so we need to adjust lowmem to match the amount we can map
 155          * in the fixed entries */
 156         adjust_total_lowmem();
 157 #endif /* CONFIG_FSL_BOOKE */
 158
 159         if (total_lowmem > __max_low_memory) {
 160                 total_lowmem = __max_low_memory;
 161                 lowmem_end_addr = memstart_addr + total_lowmem;
 162 #ifndef CONFIG_HIGHMEM
 163                 total_memory = total_lowmem;
 164                 memblock_enforce_memory_limit(total_lowmem);
 165 #endif /* CONFIG_HIGHMEM */
 166         }
 167
 168         /* Initialize the MMU hardware */
 169         if (ppc_md.progress)
 170                 ppc_md.progress("MMU:hw init", 0x300);
 171         MMU_init_hw();
 172
 173         /* Map in all of RAM starting at KERNELBASE */
 174         if (ppc_md.progress)
 175                 ppc_md.progress("MMU:mapin", 0x301);
 176         mapin_ram();
 177
 178         /* Initialize early top-down ioremap allocator */
 179         ioremap_bot = IOREMAP_TOP;
 180
 181         if (ppc_md.progress)
 182                 ppc_md.progress("MMU:exit", 0x211);
 183
 184         /* From now on, btext is no longer BAT mapped if it was at all */
 185 #ifdef CONFIG_BOOTX_TEXT
 186         btext_unmap();
 187 #endif
 188
 189         /* Shortly after that, the entire linear mapping will be available */
 190         memblock_set_current_limit(lowmem_end_addr);
 191 }