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 /* max amount of low RAM to map in */ 92 unsigned long __max_low_memory = MAX_LOW_MEM; 93 94 /* 95 * Check for command-line options that affect what MMU_init will do. 96 */ 97 static void __init MMU_setup(void) 98 { 99 /* Check for nobats option (used in mapin_ram). */ 100 if (strstr(boot_command_line, "nobats")) { 101 __map_without_bats = 1; 102 } 103 104 if (strstr(boot_command_line, "noltlbs")) { 105 __map_without_ltlbs = 1; 106 } 107 if (debug_pagealloc_enabled()) { 108 __map_without_bats = 1; 109 __map_without_ltlbs = 1; 110 } 111 if (strict_kernel_rwx_enabled() && !IS_ENABLED(CONFIG_PPC_8xx)) 112 __map_without_ltlbs = 1; 113 } 114 115 /* 116 * MMU_init sets up the basic memory mappings for the kernel, 117 * including both RAM and possibly some I/O regions, 118 * and sets up the page tables and the MMU hardware ready to go. 119 */ 120 void __init MMU_init(void) 121 { 122 if (ppc_md.progress) 123 ppc_md.progress("MMU:enter", 0x111); 124 125 /* parse args from command line */ 126 MMU_setup(); 127 128 /* 129 * Reserve gigantic pages for hugetlb. This MUST occur before 130 * lowmem_end_addr is initialized below. 131 */ 132 if (memblock.memory.cnt > 1) { 133 #ifndef CONFIG_WII 134 memblock_enforce_memory_limit(memblock.memory.regions[0].size); 135 pr_warn("Only using first contiguous memory region\n"); 136 #else 137 wii_memory_fixups(); 138 #endif 139 } 140 141 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr; 142 lowmem_end_addr = memstart_addr + total_lowmem; 143 144 #ifdef CONFIG_FSL_BOOKE 145 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 146 * entries, so we need to adjust lowmem to match the amount we can map 147 * in the fixed entries */ 148 adjust_total_lowmem(); 149 #endif /* CONFIG_FSL_BOOKE */ 150 151 if (total_lowmem > __max_low_memory) { 152 total_lowmem = __max_low_memory; 153 lowmem_end_addr = memstart_addr + total_lowmem; 154 #ifndef CONFIG_HIGHMEM 155 total_memory = total_lowmem; 156 memblock_enforce_memory_limit(total_lowmem); 157 #endif /* CONFIG_HIGHMEM */ 158 } 159 160 /* Initialize the MMU hardware */ 161 if (ppc_md.progress) 162 ppc_md.progress("MMU:hw init", 0x300); 163 MMU_init_hw(); 164 165 /* Map in all of RAM starting at KERNELBASE */ 166 if (ppc_md.progress) 167 ppc_md.progress("MMU:mapin", 0x301); 168 mapin_ram(); 169 170 /* Initialize early top-down ioremap allocator */ 171 ioremap_bot = IOREMAP_TOP; 172 173 if (ppc_md.progress) 174 ppc_md.progress("MMU:exit", 0x211); 175 176 /* From now on, btext is no longer BAT mapped if it was at all */ 177 #ifdef CONFIG_BOOTX_TEXT 178 btext_unmap(); 179 #endif 180 181 /* Shortly after that, the entire linear mapping will be available */ 182 memblock_set_current_limit(lowmem_end_addr); 183 } 184