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 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 /* 84 * this tells the system to map all of ram with the segregs 85 * (i.e. page tables) instead of the bats. 86 * -- Cort 87 */ 88 int __map_without_bats; 89 int __map_without_ltlbs; 90 91 /* 92 * This tells the system to allow ioremapping memory marked as reserved. 93 */ 94 int __allow_ioremap_reserved; 95 96 /* max amount of low RAM to map in */ 97 unsigned long __max_low_memory = MAX_LOW_MEM; 98 99 /* 100 * Check for command-line options that affect what MMU_init will do. 101 */ 102 void __init MMU_setup(void) 103 { 104 /* Check for nobats option (used in mapin_ram). */ 105 if (strstr(boot_command_line, "nobats")) { 106 __map_without_bats = 1; 107 } 108 109 if (strstr(boot_command_line, "noltlbs")) { 110 __map_without_ltlbs = 1; 111 } 112 if (debug_pagealloc_enabled()) { 113 __map_without_bats = 1; 114 __map_without_ltlbs = 1; 115 } 116 } 117 118 /* 119 * MMU_init sets up the basic memory mappings for the kernel, 120 * including both RAM and possibly some I/O regions, 121 * and sets up the page tables and the MMU hardware ready to go. 122 */ 123 void __init MMU_init(void) 124 { 125 if (ppc_md.progress) 126 ppc_md.progress("MMU:enter", 0x111); 127 128 /* parse args from command line */ 129 MMU_setup(); 130 131 /* 132 * Reserve gigantic pages for hugetlb. This MUST occur before 133 * lowmem_end_addr is initialized below. 134 */ 135 reserve_hugetlb_gpages(); 136 137 if (memblock.memory.cnt > 1) { 138 #ifndef CONFIG_WII 139 memblock_enforce_memory_limit(memblock.memory.regions[0].size); 140 pr_warn("Only using first contiguous memory region\n"); 141 #else 142 wii_memory_fixups(); 143 #endif 144 } 145 146 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr; 147 lowmem_end_addr = memstart_addr + total_lowmem; 148 149 #ifdef CONFIG_FSL_BOOKE 150 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 151 * entries, so we need to adjust lowmem to match the amount we can map 152 * in the fixed entries */ 153 adjust_total_lowmem(); 154 #endif /* CONFIG_FSL_BOOKE */ 155 156 if (total_lowmem > __max_low_memory) { 157 total_lowmem = __max_low_memory; 158 lowmem_end_addr = memstart_addr + total_lowmem; 159 #ifndef CONFIG_HIGHMEM 160 total_memory = total_lowmem; 161 memblock_enforce_memory_limit(total_lowmem); 162 #endif /* CONFIG_HIGHMEM */ 163 } 164 165 /* Initialize the MMU hardware */ 166 if (ppc_md.progress) 167 ppc_md.progress("MMU:hw init", 0x300); 168 MMU_init_hw(); 169 170 /* Map in all of RAM starting at KERNELBASE */ 171 if (ppc_md.progress) 172 ppc_md.progress("MMU:mapin", 0x301); 173 mapin_ram(); 174 175 /* Initialize early top-down ioremap allocator */ 176 ioremap_bot = IOREMAP_TOP; 177 178 if (ppc_md.progress) 179 ppc_md.progress("MMU:exit", 0x211); 180 181 /* From now on, btext is no longer BAT mapped if it was at all */ 182 #ifdef CONFIG_BOOTX_TEXT 183 btext_unmap(); 184 #endif 185 186 /* Shortly after that, the entire linear mapping will be available */ 187 memblock_set_current_limit(lowmem_end_addr); 188 } 189