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/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/system.h>
  49 #include <asm/hugetlb.h>
  50
  51 #include "mmu_decl.h"
  52
  53 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
  54 /* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
  55 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
  56 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
  57 #endif
  58 #endif
  59 #define MAX_LOW_MEM     CONFIG_LOWMEM_SIZE
  60
  61 phys_addr_t total_memory;
  62 phys_addr_t total_lowmem;
  63
  64 phys_addr_t memstart_addr = (phys_addr_t)~0ull;
  65 EXPORT_SYMBOL(memstart_addr);
  66 phys_addr_t kernstart_addr;
  67 EXPORT_SYMBOL(kernstart_addr);
  68
  69 #ifdef CONFIG_RELOCATABLE_PPC32
  70 /* Used in __va()/__pa() */
  71 long long virt_phys_offset;
  72 EXPORT_SYMBOL(virt_phys_offset);
  73 #endif
  74
  75 phys_addr_t lowmem_end_addr;
  76
  77 int boot_mapsize;
  78 #ifdef CONFIG_PPC_PMAC
  79 unsigned long agp_special_page;
  80 EXPORT_SYMBOL(agp_special_page);
  81 #endif
  82
  83 void MMU_init(void);
  84
  85 /* XXX should be in current.h  -- paulus */
  86 extern struct task_struct *current_set[NR_CPUS];
  87
  88 /*
  89  * this tells the system to map all of ram with the segregs
  90  * (i.e. page tables) instead of the bats.
  91  * -- Cort
  92  */
  93 int __map_without_bats;
  94 int __map_without_ltlbs;
  95
  96 /*
  97  * This tells the system to allow ioremapping memory marked as reserved.
  98  */
  99 int __allow_ioremap_reserved;
 100
 101 /* max amount of low RAM to map in */
 102 unsigned long __max_low_memory = MAX_LOW_MEM;
 103
 104 /*
 105  * Check for command-line options that affect what MMU_init will do.
 106  */
 107 void MMU_setup(void)
 108 {
 109         /* Check for nobats option (used in mapin_ram). */
 110         if (strstr(cmd_line, "nobats")) {
 111                 __map_without_bats = 1;
 112         }
 113
 114         if (strstr(cmd_line, "noltlbs")) {
 115                 __map_without_ltlbs = 1;
 116         }
 117 #ifdef CONFIG_DEBUG_PAGEALLOC
 118         __map_without_bats = 1;
 119         __map_without_ltlbs = 1;
 120 #endif
 121 }
 122
 123 /*
 124  * MMU_init sets up the basic memory mappings for the kernel,
 125  * including both RAM and possibly some I/O regions,
 126  * and sets up the page tables and the MMU hardware ready to go.
 127  */
 128 void __init MMU_init(void)
 129 {
 130         if (ppc_md.progress)
 131                 ppc_md.progress("MMU:enter", 0x111);
 132
 133         /* parse args from command line */
 134         MMU_setup();
 135
 136         /*
 137          * Reserve gigantic pages for hugetlb.  This MUST occur before
 138          * lowmem_end_addr is initialized below.
 139          */
 140         reserve_hugetlb_gpages();
 141
 142         if (memblock.memory.cnt > 1) {
 143 #ifndef CONFIG_WII
 144                 memblock_enforce_memory_limit(memblock.memory.regions[0].size);
 145                 printk(KERN_WARNING "Only using first contiguous memory region");
 146 #else
 147                 wii_memory_fixups();
 148 #endif
 149         }
 150
 151         total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
 152         lowmem_end_addr = memstart_addr + total_lowmem;
 153
 154 #ifdef CONFIG_FSL_BOOKE
 155         /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
 156          * entries, so we need to adjust lowmem to match the amount we can map
 157          * in the fixed entries */
 158         adjust_total_lowmem();
 159 #endif /* CONFIG_FSL_BOOKE */
 160
 161         if (total_lowmem > __max_low_memory) {
 162                 total_lowmem = __max_low_memory;
 163                 lowmem_end_addr = memstart_addr + total_lowmem;
 164 #ifndef CONFIG_HIGHMEM
 165                 total_memory = total_lowmem;
 166                 memblock_enforce_memory_limit(total_lowmem);
 167 #endif /* CONFIG_HIGHMEM */
 168         }
 169
 170         /* Initialize the MMU hardware */
 171         if (ppc_md.progress)
 172                 ppc_md.progress("MMU:hw init", 0x300);
 173         MMU_init_hw();
 174
 175         /* Map in all of RAM starting at KERNELBASE */
 176         if (ppc_md.progress)
 177                 ppc_md.progress("MMU:mapin", 0x301);
 178         mapin_ram();
 179
 180         /* Initialize early top-down ioremap allocator */
 181         ioremap_bot = IOREMAP_TOP;
 182
 183         /* Map in I/O resources */
 184         if (ppc_md.progress)
 185                 ppc_md.progress("MMU:setio", 0x302);
 186
 187         if (ppc_md.progress)
 188                 ppc_md.progress("MMU:exit", 0x211);
 189
 190         /* From now on, btext is no longer BAT mapped if it was at all */
 191 #ifdef CONFIG_BOOTX_TEXT
 192         btext_unmap();
 193 #endif
 194
 195         /* Shortly after that, the entire linear mapping will be available */
 196         memblock_set_current_limit(lowmem_end_addr);
 197 }
 198
 199 /* This is only called until mem_init is done. */
 200 void __init *early_get_page(void)
 201 {
 202         if (init_bootmem_done)
 203                 return alloc_bootmem_pages(PAGE_SIZE);
 204         else
 205                 return __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
 206 }
 207
 208 #ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
 209 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 210                                 phys_addr_t first_memblock_size)
 211 {
 212         /* We don't currently support the first MEMBLOCK not mapping 0
 213          * physical on those processors
 214          */
 215         BUG_ON(first_memblock_base != 0);
 216
 217         /* 8xx can only access 8MB at the moment */
 218         memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000));
 219 }
 220 #endif /* CONFIG_8xx */