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 54 phys_addr_t total_memory; 55 phys_addr_t total_lowmem; 56 57 #ifdef CONFIG_RELOCATABLE 58 /* Used in __va()/__pa() */ 59 long long virt_phys_offset; 60 EXPORT_SYMBOL(virt_phys_offset); 61 #endif 62 63 phys_addr_t lowmem_end_addr; 64 65 int boot_mapsize; 66 #ifdef CONFIG_PPC_PMAC 67 unsigned long agp_special_page; 68 EXPORT_SYMBOL(agp_special_page); 69 #endif 70 71 void 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 */ 78 int __map_without_bats; 79 int __map_without_ltlbs; 80 81 /* max amount of low RAM to map in */ 82 unsigned long __max_low_memory = MAX_LOW_MEM; 83 84 /* 85 * Check for command-line options that affect what MMU_init will do. 86 */ 87 static 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 */ 115 void __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