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 #include <asm/kup.h> 49 #include <asm/kasan.h> 50 51 #include <mm/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_KERNEL_START" 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 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 /* 86 * this tells the system to map all of ram with the segregs 87 * (i.e. page tables) instead of the bats. 88 * -- Cort 89 */ 90 int __map_without_bats; 91 int __map_without_ltlbs; 92 93 /* max amount of low RAM to map in */ 94 unsigned long __max_low_memory = MAX_LOW_MEM; 95 96 /* 97 * Check for command-line options that affect what MMU_init will do. 98 */ 99 static void __init MMU_setup(void) 100 { 101 /* Check for nobats option (used in mapin_ram). */ 102 if (strstr(boot_command_line, "nobats")) { 103 __map_without_bats = 1; 104 } 105 106 if (strstr(boot_command_line, "noltlbs")) { 107 __map_without_ltlbs = 1; 108 } 109 if (debug_pagealloc_enabled()) { 110 __map_without_bats = 1; 111 __map_without_ltlbs = 1; 112 } 113 if (strict_kernel_rwx_enabled() && !IS_ENABLED(CONFIG_PPC_8xx)) 114 __map_without_ltlbs = 1; 115 } 116 117 /* 118 * MMU_init sets up the basic memory mappings for the kernel, 119 * including both RAM and possibly some I/O regions, 120 * and sets up the page tables and the MMU hardware ready to go. 121 */ 122 void __init MMU_init(void) 123 { 124 if (ppc_md.progress) 125 ppc_md.progress("MMU:enter", 0x111); 126 127 /* parse args from command line */ 128 MMU_setup(); 129 130 /* 131 * Reserve gigantic pages for hugetlb. This MUST occur before 132 * lowmem_end_addr is initialized below. 133 */ 134 if (memblock.memory.cnt > 1) { 135 #ifndef CONFIG_WII 136 memblock_enforce_memory_limit(memblock.memory.regions[0].size); 137 pr_warn("Only using first contiguous memory region\n"); 138 #else 139 wii_memory_fixups(); 140 #endif 141 } 142 143 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr; 144 lowmem_end_addr = memstart_addr + total_lowmem; 145 146 #ifdef CONFIG_FSL_BOOKE 147 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 148 * entries, so we need to adjust lowmem to match the amount we can map 149 * in the fixed entries */ 150 adjust_total_lowmem(); 151 #endif /* CONFIG_FSL_BOOKE */ 152 153 if (total_lowmem > __max_low_memory) { 154 total_lowmem = __max_low_memory; 155 lowmem_end_addr = memstart_addr + total_lowmem; 156 #ifndef CONFIG_HIGHMEM 157 total_memory = total_lowmem; 158 memblock_enforce_memory_limit(total_lowmem); 159 #endif /* CONFIG_HIGHMEM */ 160 } 161 162 /* Initialize the MMU hardware */ 163 if (ppc_md.progress) 164 ppc_md.progress("MMU:hw init", 0x300); 165 MMU_init_hw(); 166 167 /* Map in all of RAM starting at KERNELBASE */ 168 if (ppc_md.progress) 169 ppc_md.progress("MMU:mapin", 0x301); 170 mapin_ram(); 171 172 /* Initialize early top-down ioremap allocator */ 173 ioremap_bot = IOREMAP_TOP; 174 175 if (ppc_md.progress) 176 ppc_md.progress("MMU:exit", 0x211); 177 178 /* From now on, btext is no longer BAT mapped if it was at all */ 179 #ifdef CONFIG_BOOTX_TEXT 180 btext_unmap(); 181 #endif 182 183 kasan_mmu_init(); 184 185 setup_kup(); 186 187 /* Shortly after that, the entire linear mapping will be available */ 188 memblock_set_current_limit(lowmem_end_addr); 189 } 190