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