1 /* 2 * PowerPC version 3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 4 * 5 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 6 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 7 * Copyright (C) 1996 Paul Mackerras 8 * PPC44x/36-bit changes by Matt Porter (mporter@mvista.com) 9 * 10 * Derived from "arch/i386/mm/init.c" 11 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License 15 * as published by the Free Software Foundation; either version 16 * 2 of the License, or (at your option) any later version. 17 * 18 */ 19 20 #include <linux/module.h> 21 #include <linux/sched.h> 22 #include <linux/kernel.h> 23 #include <linux/errno.h> 24 #include <linux/string.h> 25 #include <linux/types.h> 26 #include <linux/mm.h> 27 #include <linux/stddef.h> 28 #include <linux/init.h> 29 #include <linux/bootmem.h> 30 #include <linux/highmem.h> 31 #include <linux/initrd.h> 32 #include <linux/pagemap.h> 33 #include <linux/memblock.h> 34 #include <linux/gfp.h> 35 36 #include <asm/pgalloc.h> 37 #include <asm/prom.h> 38 #include <asm/io.h> 39 #include <asm/pgtable.h> 40 #include <asm/mmu.h> 41 #include <asm/smp.h> 42 #include <asm/machdep.h> 43 #include <asm/btext.h> 44 #include <asm/tlb.h> 45 #include <asm/sections.h> 46 #include <asm/system.h> 47 48 #include "mmu_decl.h" 49 50 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL) 51 /* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */ 52 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET)) 53 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL" 54 #endif 55 #endif 56 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE 57 58 phys_addr_t total_memory; 59 phys_addr_t total_lowmem; 60 61 phys_addr_t memstart_addr = (phys_addr_t)~0ull; 62 EXPORT_SYMBOL(memstart_addr); 63 phys_addr_t kernstart_addr; 64 EXPORT_SYMBOL(kernstart_addr); 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 /* XXX should be in current.h -- paulus */ 76 extern struct task_struct *current_set[NR_CPUS]; 77 78 /* 79 * this tells the system to map all of ram with the segregs 80 * (i.e. page tables) instead of the bats. 81 * -- Cort 82 */ 83 int __map_without_bats; 84 int __map_without_ltlbs; 85 86 /* 87 * This tells the system to allow ioremapping memory marked as reserved. 88 */ 89 int __allow_ioremap_reserved; 90 91 /* max amount of low RAM to map in */ 92 unsigned long __max_low_memory = MAX_LOW_MEM; 93 94 /* 95 * Check for command-line options that affect what MMU_init will do. 96 */ 97 void MMU_setup(void) 98 { 99 /* Check for nobats option (used in mapin_ram). */ 100 if (strstr(cmd_line, "nobats")) { 101 __map_without_bats = 1; 102 } 103 104 if (strstr(cmd_line, "noltlbs")) { 105 __map_without_ltlbs = 1; 106 } 107 #ifdef CONFIG_DEBUG_PAGEALLOC 108 __map_without_bats = 1; 109 __map_without_ltlbs = 1; 110 #endif 111 } 112 113 /* 114 * MMU_init sets up the basic memory mappings for the kernel, 115 * including both RAM and possibly some I/O regions, 116 * and sets up the page tables and the MMU hardware ready to go. 117 */ 118 void __init MMU_init(void) 119 { 120 if (ppc_md.progress) 121 ppc_md.progress("MMU:enter", 0x111); 122 123 /* parse args from command line */ 124 MMU_setup(); 125 126 if (memblock.memory.cnt > 1) { 127 #ifndef CONFIG_WII 128 memblock.memory.cnt = 1; 129 memblock_analyze(); 130 printk(KERN_WARNING "Only using first contiguous memory region"); 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 memblock_analyze(); 153 #endif /* CONFIG_HIGHMEM */ 154 } 155 156 /* Initialize the MMU hardware */ 157 if (ppc_md.progress) 158 ppc_md.progress("MMU:hw init", 0x300); 159 MMU_init_hw(); 160 161 /* Map in all of RAM starting at KERNELBASE */ 162 if (ppc_md.progress) 163 ppc_md.progress("MMU:mapin", 0x301); 164 mapin_ram(); 165 166 /* Initialize early top-down ioremap allocator */ 167 ioremap_bot = IOREMAP_TOP; 168 169 /* Map in I/O resources */ 170 if (ppc_md.progress) 171 ppc_md.progress("MMU:setio", 0x302); 172 173 if (ppc_md.progress) 174 ppc_md.progress("MMU:exit", 0x211); 175 176 /* From now on, btext is no longer BAT mapped if it was at all */ 177 #ifdef CONFIG_BOOTX_TEXT 178 btext_unmap(); 179 #endif 180 181 /* Shortly after that, the entire linear mapping will be available */ 182 memblock_set_current_limit(lowmem_end_addr); 183 } 184 185 /* This is only called until mem_init is done. */ 186 void __init *early_get_page(void) 187 { 188 if (init_bootmem_done) 189 return alloc_bootmem_pages(PAGE_SIZE); 190 else 191 return __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE)); 192 } 193 194 /* Free up now-unused memory */ 195 static void free_sec(unsigned long start, unsigned long end, const char *name) 196 { 197 unsigned long cnt = 0; 198 199 while (start < end) { 200 ClearPageReserved(virt_to_page(start)); 201 init_page_count(virt_to_page(start)); 202 free_page(start); 203 cnt++; 204 start += PAGE_SIZE; 205 } 206 if (cnt) { 207 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name); 208 totalram_pages += cnt; 209 } 210 } 211 212 void free_initmem(void) 213 { 214 #define FREESEC(TYPE) \ 215 free_sec((unsigned long)(&__ ## TYPE ## _begin), \ 216 (unsigned long)(&__ ## TYPE ## _end), \ 217 #TYPE); 218 219 printk ("Freeing unused kernel memory:"); 220 FREESEC(init); 221 printk("\n"); 222 ppc_md.progress = NULL; 223 #undef FREESEC 224 } 225 226 #ifdef CONFIG_BLK_DEV_INITRD 227 void free_initrd_mem(unsigned long start, unsigned long end) 228 { 229 if (start < end) 230 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10); 231 for (; start < end; start += PAGE_SIZE) { 232 ClearPageReserved(virt_to_page(start)); 233 init_page_count(virt_to_page(start)); 234 free_page(start); 235 totalram_pages++; 236 } 237 } 238 #endif 239 240 241 #ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */ 242 void setup_initial_memory_limit(phys_addr_t first_memblock_base, 243 phys_addr_t first_memblock_size) 244 { 245 /* We don't currently support the first MEMBLOCK not mapping 0 246 * physical on those processors 247 */ 248 BUG_ON(first_memblock_base != 0); 249 250 /* 8xx can only access 8MB at the moment */ 251 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000)); 252 } 253 #endif /* CONFIG_8xx */ 254