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 * address of the limit of what is accessible with initial MMU setup - 96 * 256MB usually, but only 16MB on 601. 97 */ 98 phys_addr_t __initial_memory_limit_addr = (phys_addr_t)0x10000000; 99 100 /* 101 * Check for command-line options that affect what MMU_init will do. 102 */ 103 void MMU_setup(void) 104 { 105 /* Check for nobats option (used in mapin_ram). */ 106 if (strstr(cmd_line, "nobats")) { 107 __map_without_bats = 1; 108 } 109 110 if (strstr(cmd_line, "noltlbs")) { 111 __map_without_ltlbs = 1; 112 } 113 #ifdef CONFIG_DEBUG_PAGEALLOC 114 __map_without_bats = 1; 115 __map_without_ltlbs = 1; 116 #endif 117 } 118 119 /* 120 * MMU_init sets up the basic memory mappings for the kernel, 121 * including both RAM and possibly some I/O regions, 122 * and sets up the page tables and the MMU hardware ready to go. 123 */ 124 void __init MMU_init(void) 125 { 126 if (ppc_md.progress) 127 ppc_md.progress("MMU:enter", 0x111); 128 129 /* 601 can only access 16MB at the moment */ 130 if (PVR_VER(mfspr(SPRN_PVR)) == 1) 131 __initial_memory_limit_addr = 0x01000000; 132 /* 8xx can only access 8MB at the moment */ 133 if (PVR_VER(mfspr(SPRN_PVR)) == 0x50) 134 __initial_memory_limit_addr = 0x00800000; 135 136 /* parse args from command line */ 137 MMU_setup(); 138 139 if (memblock.memory.cnt > 1) { 140 #ifndef CONFIG_WII 141 memblock.memory.cnt = 1; 142 memblock_analyze(); 143 printk(KERN_WARNING "Only using first contiguous memory region"); 144 #else 145 wii_memory_fixups(); 146 #endif 147 } 148 149 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr; 150 lowmem_end_addr = memstart_addr + total_lowmem; 151 152 #ifdef CONFIG_FSL_BOOKE 153 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 154 * entries, so we need to adjust lowmem to match the amount we can map 155 * in the fixed entries */ 156 adjust_total_lowmem(); 157 #endif /* CONFIG_FSL_BOOKE */ 158 159 if (total_lowmem > __max_low_memory) { 160 total_lowmem = __max_low_memory; 161 lowmem_end_addr = memstart_addr + total_lowmem; 162 #ifndef CONFIG_HIGHMEM 163 total_memory = total_lowmem; 164 memblock_enforce_memory_limit(lowmem_end_addr); 165 memblock_analyze(); 166 #endif /* CONFIG_HIGHMEM */ 167 } 168 169 /* Initialize the MMU hardware */ 170 if (ppc_md.progress) 171 ppc_md.progress("MMU:hw init", 0x300); 172 MMU_init_hw(); 173 174 /* Map in all of RAM starting at KERNELBASE */ 175 if (ppc_md.progress) 176 ppc_md.progress("MMU:mapin", 0x301); 177 mapin_ram(); 178 179 /* Initialize early top-down ioremap allocator */ 180 ioremap_bot = IOREMAP_TOP; 181 182 /* Map in I/O resources */ 183 if (ppc_md.progress) 184 ppc_md.progress("MMU:setio", 0x302); 185 186 if (ppc_md.progress) 187 ppc_md.progress("MMU:exit", 0x211); 188 189 /* From now on, btext is no longer BAT mapped if it was at all */ 190 #ifdef CONFIG_BOOTX_TEXT 191 btext_unmap(); 192 #endif 193 } 194 195 /* This is only called until mem_init is done. */ 196 void __init *early_get_page(void) 197 { 198 void *p; 199 200 if (init_bootmem_done) { 201 p = alloc_bootmem_pages(PAGE_SIZE); 202 } else { 203 p = __va(memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 204 __initial_memory_limit_addr)); 205 } 206 return p; 207 } 208 209 /* Free up now-unused memory */ 210 static void free_sec(unsigned long start, unsigned long end, const char *name) 211 { 212 unsigned long cnt = 0; 213 214 while (start < end) { 215 ClearPageReserved(virt_to_page(start)); 216 init_page_count(virt_to_page(start)); 217 free_page(start); 218 cnt++; 219 start += PAGE_SIZE; 220 } 221 if (cnt) { 222 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name); 223 totalram_pages += cnt; 224 } 225 } 226 227 void free_initmem(void) 228 { 229 #define FREESEC(TYPE) \ 230 free_sec((unsigned long)(&__ ## TYPE ## _begin), \ 231 (unsigned long)(&__ ## TYPE ## _end), \ 232 #TYPE); 233 234 printk ("Freeing unused kernel memory:"); 235 FREESEC(init); 236 printk("\n"); 237 ppc_md.progress = NULL; 238 #undef FREESEC 239 } 240 241 #ifdef CONFIG_BLK_DEV_INITRD 242 void free_initrd_mem(unsigned long start, unsigned long end) 243 { 244 if (start < end) 245 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10); 246 for (; start < end; start += PAGE_SIZE) { 247 ClearPageReserved(virt_to_page(start)); 248 init_page_count(virt_to_page(start)); 249 free_page(start); 250 totalram_pages++; 251 } 252 } 253 #endif 254 255