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 #ifdef CONFIG_STRICT_KERNEL_RWX 117 if (rodata_enabled) { 118 __map_without_bats = 1; 119 __map_without_ltlbs = 1; 120 } 121 #endif 122 } 123 124 /* 125 * MMU_init sets up the basic memory mappings for the kernel, 126 * including both RAM and possibly some I/O regions, 127 * and sets up the page tables and the MMU hardware ready to go. 128 */ 129 void __init MMU_init(void) 130 { 131 if (ppc_md.progress) 132 ppc_md.progress("MMU:enter", 0x111); 133 134 /* parse args from command line */ 135 MMU_setup(); 136 137 /* 138 * Reserve gigantic pages for hugetlb. This MUST occur before 139 * lowmem_end_addr is initialized below. 140 */ 141 if (memblock.memory.cnt > 1) { 142 #ifndef CONFIG_WII 143 memblock_enforce_memory_limit(memblock.memory.regions[0].size); 144 pr_warn("Only using first contiguous memory region\n"); 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 if (ppc_md.progress) 183 ppc_md.progress("MMU:exit", 0x211); 184 185 /* From now on, btext is no longer BAT mapped if it was at all */ 186 #ifdef CONFIG_BOOTX_TEXT 187 btext_unmap(); 188 #endif 189 190 /* Shortly after that, the entire linear mapping will be available */ 191 memblock_set_current_limit(lowmem_end_addr); 192 } 193