1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * PowerPC version 4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 5 * 6 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 7 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 8 * Copyright (C) 1996 Paul Mackerras 9 * PPC44x/36-bit changes by Matt Porter (mporter@mvista.com) 10 * 11 * Derived from "arch/i386/mm/init.c" 12 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 13 */ 14 15#include <linux/module.h> 16#include <linux/sched.h> 17#include <linux/kernel.h> 18#include <linux/errno.h> 19#include <linux/string.h> 20#include <linux/types.h> 21#include <linux/mm.h> 22#include <linux/stddef.h> 23#include <linux/init.h> 24#include <linux/highmem.h> 25#include <linux/initrd.h> 26#include <linux/pagemap.h> 27#include <linux/memblock.h> 28#include <linux/gfp.h> 29#include <linux/slab.h> 30#include <linux/hugetlb.h> 31 32#include <asm/prom.h> 33#include <asm/io.h> 34#include <asm/mmu.h> 35#include <asm/smp.h> 36#include <asm/machdep.h> 37#include <asm/btext.h> 38#include <asm/tlb.h> 39#include <asm/sections.h> 40#include <asm/hugetlb.h> 41#include <asm/kup.h> 42#include <asm/kasan.h> 43 44#include <mm/mmu_decl.h> 45 46#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL) 47/* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */ 48#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET)) 49#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START" 50#endif 51#endif 52#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE 53 54phys_addr_t total_memory; 55phys_addr_t total_lowmem; 56 57#ifdef CONFIG_RELOCATABLE 58/* Used in __va()/__pa() */ 59long long virt_phys_offset; 60EXPORT_SYMBOL(virt_phys_offset); 61#endif 62 63phys_addr_t lowmem_end_addr; 64 65int boot_mapsize; 66#ifdef CONFIG_PPC_PMAC 67unsigned long agp_special_page; 68EXPORT_SYMBOL(agp_special_page); 69#endif 70 71void MMU_init(void); 72 73/* 74 * this tells the system to map all of ram with the segregs 75 * (i.e. page tables) instead of the bats. 76 * -- Cort 77 */ 78int __map_without_bats; 79int __map_without_ltlbs; 80 81/* max amount of low RAM to map in */ 82unsigned long __max_low_memory = MAX_LOW_MEM; 83 84/* 85 * Check for command-line options that affect what MMU_init will do. 86 */ 87static void __init MMU_setup(void) 88{ 89 /* Check for nobats option (used in mapin_ram). */ 90 if (strstr(boot_command_line, "nobats")) { 91 __map_without_bats = 1; 92 } 93 94 if (strstr(boot_command_line, "noltlbs")) { 95 __map_without_ltlbs = 1; 96 } 97 if (IS_ENABLED(CONFIG_PPC_8xx)) 98 return; 99 100 if (IS_ENABLED(CONFIG_KFENCE)) 101 __map_without_ltlbs = 1; 102 103 if (debug_pagealloc_enabled()) 104 __map_without_ltlbs = 1; 105 106 if (strict_kernel_rwx_enabled()) 107 __map_without_ltlbs = 1; 108} 109 110/* 111 * MMU_init sets up the basic memory mappings for the kernel, 112 * including both RAM and possibly some I/O regions, 113 * and sets up the page tables and the MMU hardware ready to go. 114 */ 115void __init MMU_init(void) 116{ 117 if (ppc_md.progress) 118 ppc_md.progress("MMU:enter", 0x111); 119 120 /* parse args from command line */ 121 MMU_setup(); 122 123 /* 124 * Reserve gigantic pages for hugetlb. This MUST occur before 125 * lowmem_end_addr is initialized below. 126 */ 127 if (memblock.memory.cnt > 1) { 128#ifndef CONFIG_WII 129 memblock_enforce_memory_limit(memblock.memory.regions[0].size); 130 pr_warn("Only using first contiguous memory region\n"); 131#else 132 wii_memory_fixups(); 133#endif 134 } 135 136 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr; 137 lowmem_end_addr = memstart_addr + total_lowmem; 138 139#ifdef CONFIG_FSL_BOOKE 140 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 141 * entries, so we need to adjust lowmem to match the amount we can map 142 * in the fixed entries */ 143 adjust_total_lowmem(); 144#endif /* CONFIG_FSL_BOOKE */ 145 146 if (total_lowmem > __max_low_memory) { 147 total_lowmem = __max_low_memory; 148 lowmem_end_addr = memstart_addr + total_lowmem; 149#ifndef CONFIG_HIGHMEM 150 total_memory = total_lowmem; 151 memblock_enforce_memory_limit(total_lowmem); 152#endif /* CONFIG_HIGHMEM */ 153 } 154 155 /* Initialize the MMU hardware */ 156 if (ppc_md.progress) 157 ppc_md.progress("MMU:hw init", 0x300); 158 MMU_init_hw(); 159 160 /* Map in all of RAM starting at KERNELBASE */ 161 if (ppc_md.progress) 162 ppc_md.progress("MMU:mapin", 0x301); 163 mapin_ram(); 164 165 /* Initialize early top-down ioremap allocator */ 166 ioremap_bot = IOREMAP_TOP; 167 168 if (ppc_md.progress) 169 ppc_md.progress("MMU:exit", 0x211); 170 171 /* From now on, btext is no longer BAT mapped if it was at all */ 172#ifdef CONFIG_BOOTX_TEXT 173 btext_unmap(); 174#endif 175 176 kasan_mmu_init(); 177 178 setup_kup(); 179 180 /* Shortly after that, the entire linear mapping will be available */ 181 memblock_set_current_limit(lowmem_end_addr); 182} 183