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