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 /* max amount of low RAM to map in */ 73 unsigned long __max_low_memory = MAX_LOW_MEM; 74 75 /* 76 * MMU_init sets up the basic memory mappings for the kernel, 77 * including both RAM and possibly some I/O regions, 78 * and sets up the page tables and the MMU hardware ready to go. 79 */ 80 void __init MMU_init(void) 81 { 82 if (ppc_md.progress) 83 ppc_md.progress("MMU:enter", 0x111); 84 85 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr; 86 lowmem_end_addr = memstart_addr + total_lowmem; 87 88 #ifdef CONFIG_PPC_85xx 89 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 90 * entries, so we need to adjust lowmem to match the amount we can map 91 * in the fixed entries */ 92 adjust_total_lowmem(); 93 #endif /* CONFIG_PPC_85xx */ 94 95 if (total_lowmem > __max_low_memory) { 96 total_lowmem = __max_low_memory; 97 lowmem_end_addr = memstart_addr + total_lowmem; 98 #ifndef CONFIG_HIGHMEM 99 total_memory = total_lowmem; 100 memblock_enforce_memory_limit(total_lowmem); 101 #endif /* CONFIG_HIGHMEM */ 102 } 103 104 /* Initialize the MMU hardware */ 105 if (ppc_md.progress) 106 ppc_md.progress("MMU:hw init", 0x300); 107 MMU_init_hw(); 108 109 /* Map in all of RAM starting at KERNELBASE */ 110 if (ppc_md.progress) 111 ppc_md.progress("MMU:mapin", 0x301); 112 mapin_ram(); 113 114 /* Initialize early top-down ioremap allocator */ 115 ioremap_bot = IOREMAP_TOP; 116 117 if (ppc_md.progress) 118 ppc_md.progress("MMU:exit", 0x211); 119 120 /* From now on, btext is no longer BAT mapped if it was at all */ 121 #ifdef CONFIG_BOOTX_TEXT 122 btext_unmap(); 123 #endif 124 125 kasan_mmu_init(); 126 127 setup_kup(); 128 129 update_mmu_feature_fixups(MMU_FTR_KUAP); 130 131 /* Shortly after that, the entire linear mapping will be available */ 132 memblock_set_current_limit(lowmem_end_addr); 133 } 134