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 59phys_addr_t total_memory; 60phys_addr_t total_lowmem; 61 62phys_addr_t memstart_addr = (phys_addr_t)~0ull; 63EXPORT_SYMBOL(memstart_addr); 64phys_addr_t kernstart_addr; 65EXPORT_SYMBOL(kernstart_addr); 66 67#ifdef CONFIG_RELOCATABLE_PPC32 68/* Used in __va()/__pa() */ 69long long virt_phys_offset; 70EXPORT_SYMBOL(virt_phys_offset); 71#endif 72 73phys_addr_t lowmem_end_addr; 74 75int boot_mapsize; 76#ifdef CONFIG_PPC_PMAC 77unsigned long agp_special_page; 78EXPORT_SYMBOL(agp_special_page); 79#endif 80 81void MMU_init(void); 82 83/* XXX should be in current.h -- paulus */ 84extern 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 */ 91int __map_without_bats; 92int __map_without_ltlbs; 93 94/* 95 * This tells the system to allow ioremapping memory marked as reserved. 96 */ 97int __allow_ioremap_reserved; 98 99/* max amount of low RAM to map in */ 100unsigned long __max_low_memory = MAX_LOW_MEM; 101 102/* 103 * Check for command-line options that affect what MMU_init will do. 104 */ 105void __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#ifdef CONFIG_DEBUG_PAGEALLOC 116 __map_without_bats = 1; 117 __map_without_ltlbs = 1; 118#endif 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 */ 126void __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 /* Map in I/O resources */ 182 if (ppc_md.progress) 183 ppc_md.progress("MMU:setio", 0x302); 184 185 if (ppc_md.progress) 186 ppc_md.progress("MMU:exit", 0x211); 187 188 /* From now on, btext is no longer BAT mapped if it was at all */ 189#ifdef CONFIG_BOOTX_TEXT 190 btext_unmap(); 191#endif 192 193 /* Shortly after that, the entire linear mapping will be available */ 194 memblock_set_current_limit(lowmem_end_addr); 195} 196 197#ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */ 198void setup_initial_memory_limit(phys_addr_t first_memblock_base, 199 phys_addr_t first_memblock_size) 200{ 201 /* We don't currently support the first MEMBLOCK not mapping 0 202 * physical on those processors 203 */ 204 BUG_ON(first_memblock_base != 0); 205 206#ifdef CONFIG_PIN_TLB 207 /* 8xx can only access 24MB at the moment */ 208 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x01800000)); 209#else 210 /* 8xx can only access 8MB at the moment */ 211 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000)); 212#endif 213} 214#endif /* CONFIG_8xx */ 215