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/pgalloc.h> 33 #include <asm/prom.h> 34 #include <asm/io.h> 35 #include <asm/pgtable.h> 36 #include <asm/mmu.h> 37 #include <asm/smp.h> 38 #include <asm/machdep.h> 39 #include <asm/btext.h> 40 #include <asm/tlb.h> 41 #include <asm/sections.h> 42 #include <asm/hugetlb.h> 43 #include <asm/kup.h> 44 #include <asm/kasan.h> 45 46 #include <mm/mmu_decl.h> 47 48 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL) 49 /* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */ 50 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET)) 51 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START" 52 #endif 53 #endif 54 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE 55 56 phys_addr_t total_memory; 57 phys_addr_t total_lowmem; 58 59 #ifdef CONFIG_RELOCATABLE 60 /* Used in __va()/__pa() */ 61 long long virt_phys_offset; 62 EXPORT_SYMBOL(virt_phys_offset); 63 #endif 64 65 phys_addr_t lowmem_end_addr; 66 67 int boot_mapsize; 68 #ifdef CONFIG_PPC_PMAC 69 unsigned long agp_special_page; 70 EXPORT_SYMBOL(agp_special_page); 71 #endif 72 73 void MMU_init(void); 74 75 /* 76 * this tells the system to map all of ram with the segregs 77 * (i.e. page tables) instead of the bats. 78 * -- Cort 79 */ 80 int __map_without_bats; 81 int __map_without_ltlbs; 82 83 /* max amount of low RAM to map in */ 84 unsigned long __max_low_memory = MAX_LOW_MEM; 85 86 /* 87 * Check for command-line options that affect what MMU_init will do. 88 */ 89 static void __init MMU_setup(void) 90 { 91 /* Check for nobats option (used in mapin_ram). */ 92 if (strstr(boot_command_line, "nobats")) { 93 __map_without_bats = 1; 94 } 95 96 if (strstr(boot_command_line, "noltlbs")) { 97 __map_without_ltlbs = 1; 98 } 99 if (debug_pagealloc_enabled()) { 100 __map_without_bats = 1; 101 __map_without_ltlbs = 1; 102 } 103 if (strict_kernel_rwx_enabled() && !IS_ENABLED(CONFIG_PPC_8xx)) 104 __map_without_ltlbs = 1; 105 } 106 107 /* 108 * MMU_init sets up the basic memory mappings for the kernel, 109 * including both RAM and possibly some I/O regions, 110 * and sets up the page tables and the MMU hardware ready to go. 111 */ 112 void __init MMU_init(void) 113 { 114 if (ppc_md.progress) 115 ppc_md.progress("MMU:enter", 0x111); 116 117 /* parse args from command line */ 118 MMU_setup(); 119 120 /* 121 * Reserve gigantic pages for hugetlb. This MUST occur before 122 * lowmem_end_addr is initialized below. 123 */ 124 if (memblock.memory.cnt > 1) { 125 #ifndef CONFIG_WII 126 memblock_enforce_memory_limit(memblock.memory.regions[0].size); 127 pr_warn("Only using first contiguous memory region\n"); 128 #else 129 wii_memory_fixups(); 130 #endif 131 } 132 133 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr; 134 lowmem_end_addr = memstart_addr + total_lowmem; 135 136 #ifdef CONFIG_FSL_BOOKE 137 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 138 * entries, so we need to adjust lowmem to match the amount we can map 139 * in the fixed entries */ 140 adjust_total_lowmem(); 141 #endif /* CONFIG_FSL_BOOKE */ 142 143 if (total_lowmem > __max_low_memory) { 144 total_lowmem = __max_low_memory; 145 lowmem_end_addr = memstart_addr + total_lowmem; 146 #ifndef CONFIG_HIGHMEM 147 total_memory = total_lowmem; 148 memblock_enforce_memory_limit(total_lowmem); 149 #endif /* CONFIG_HIGHMEM */ 150 } 151 152 /* Initialize the MMU hardware */ 153 if (ppc_md.progress) 154 ppc_md.progress("MMU:hw init", 0x300); 155 MMU_init_hw(); 156 157 /* Map in all of RAM starting at KERNELBASE */ 158 if (ppc_md.progress) 159 ppc_md.progress("MMU:mapin", 0x301); 160 mapin_ram(); 161 162 /* Initialize early top-down ioremap allocator */ 163 ioremap_bot = IOREMAP_TOP; 164 165 if (ppc_md.progress) 166 ppc_md.progress("MMU:exit", 0x211); 167 168 /* From now on, btext is no longer BAT mapped if it was at all */ 169 #ifdef CONFIG_BOOTX_TEXT 170 btext_unmap(); 171 #endif 172 173 kasan_mmu_init(); 174 175 setup_kup(); 176 177 /* Shortly after that, the entire linear mapping will be available */ 178 memblock_set_current_limit(lowmem_end_addr); 179 } 180