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 34 #include <asm/pgalloc.h> 35 #include <asm/prom.h> 36 #include <asm/io.h> 37 #include <asm/mmu_context.h> 38 #include <asm/pgtable.h> 39 #include <asm/mmu.h> 40 #include <asm/smp.h> 41 #include <asm/machdep.h> 42 #include <asm/btext.h> 43 #include <asm/tlb.h> 44 #include <asm/prom.h> 45 #include <asm/lmb.h> 46 #include <asm/sections.h> 47 48 #include "mmu_decl.h" 49 50 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL) 51 /* The ammount of lowmem must be within 0xF0000000 - KERNELBASE. */ 52 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - KERNELBASE)) 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 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); 59 60 unsigned long total_memory; 61 unsigned long total_lowmem; 62 63 unsigned long ppc_memstart; 64 unsigned long ppc_memoffset = PAGE_OFFSET; 65 66 int boot_mapsize; 67 #ifdef CONFIG_PPC_PMAC 68 unsigned long agp_special_page; 69 EXPORT_SYMBOL(agp_special_page); 70 #endif 71 72 #ifdef CONFIG_HIGHMEM 73 pte_t *kmap_pte; 74 pgprot_t kmap_prot; 75 76 EXPORT_SYMBOL(kmap_prot); 77 EXPORT_SYMBOL(kmap_pte); 78 #endif 79 80 void MMU_init(void); 81 82 /* XXX should be in current.h -- paulus */ 83 extern struct task_struct *current_set[NR_CPUS]; 84 85 extern int init_bootmem_done; 86 87 /* 88 * this tells the system to map all of ram with the segregs 89 * (i.e. page tables) instead of the bats. 90 * -- Cort 91 */ 92 int __map_without_bats; 93 int __map_without_ltlbs; 94 95 /* max amount of low RAM to map in */ 96 unsigned long __max_low_memory = MAX_LOW_MEM; 97 98 /* 99 * limit of what is accessible with initial MMU setup - 100 * 256MB usually, but only 16MB on 601. 101 */ 102 unsigned long __initial_memory_limit = 0x10000000; 103 104 /* 105 * Check for command-line options that affect what MMU_init will do. 106 */ 107 void MMU_setup(void) 108 { 109 /* Check for nobats option (used in mapin_ram). */ 110 if (strstr(cmd_line, "nobats")) { 111 __map_without_bats = 1; 112 } 113 114 if (strstr(cmd_line, "noltlbs")) { 115 __map_without_ltlbs = 1; 116 } 117 #ifdef CONFIG_DEBUG_PAGEALLOC 118 __map_without_bats = 1; 119 __map_without_ltlbs = 1; 120 #endif 121 } 122 123 /* 124 * MMU_init sets up the basic memory mappings for the kernel, 125 * including both RAM and possibly some I/O regions, 126 * and sets up the page tables and the MMU hardware ready to go. 127 */ 128 void __init MMU_init(void) 129 { 130 if (ppc_md.progress) 131 ppc_md.progress("MMU:enter", 0x111); 132 133 /* 601 can only access 16MB at the moment */ 134 if (PVR_VER(mfspr(SPRN_PVR)) == 1) 135 __initial_memory_limit = 0x01000000; 136 137 /* parse args from command line */ 138 MMU_setup(); 139 140 if (lmb.memory.cnt > 1) { 141 lmb.memory.cnt = 1; 142 lmb_analyze(); 143 printk(KERN_WARNING "Only using first contiguous memory region"); 144 } 145 146 total_memory = lmb_end_of_DRAM(); 147 total_lowmem = total_memory; 148 149 #ifdef CONFIG_FSL_BOOKE 150 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 151 * entries, so we need to adjust lowmem to match the amount we can map 152 * in the fixed entries */ 153 adjust_total_lowmem(); 154 #endif /* CONFIG_FSL_BOOKE */ 155 156 if (total_lowmem > __max_low_memory) { 157 total_lowmem = __max_low_memory; 158 #ifndef CONFIG_HIGHMEM 159 total_memory = total_lowmem; 160 lmb_enforce_memory_limit(total_lowmem); 161 lmb_analyze(); 162 #endif /* CONFIG_HIGHMEM */ 163 } 164 165 /* Initialize the MMU hardware */ 166 if (ppc_md.progress) 167 ppc_md.progress("MMU:hw init", 0x300); 168 MMU_init_hw(); 169 170 /* Map in all of RAM starting at KERNELBASE */ 171 if (ppc_md.progress) 172 ppc_md.progress("MMU:mapin", 0x301); 173 mapin_ram(); 174 175 #ifdef CONFIG_HIGHMEM 176 ioremap_base = PKMAP_BASE; 177 #else 178 ioremap_base = 0xfe000000UL; /* for now, could be 0xfffff000 */ 179 #endif /* CONFIG_HIGHMEM */ 180 ioremap_bot = ioremap_base; 181 182 /* Map in I/O resources */ 183 if (ppc_md.progress) 184 ppc_md.progress("MMU:setio", 0x302); 185 if (ppc_md.setup_io_mappings) 186 ppc_md.setup_io_mappings(); 187 188 /* Initialize the context management stuff */ 189 mmu_context_init(); 190 191 if (ppc_md.progress) 192 ppc_md.progress("MMU:exit", 0x211); 193 194 /* From now on, btext is no longer BAT mapped if it was at all */ 195 #ifdef CONFIG_BOOTX_TEXT 196 btext_unmap(); 197 #endif 198 } 199 200 /* This is only called until mem_init is done. */ 201 void __init *early_get_page(void) 202 { 203 void *p; 204 205 if (init_bootmem_done) { 206 p = alloc_bootmem_pages(PAGE_SIZE); 207 } else { 208 p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE, 209 __initial_memory_limit)); 210 } 211 return p; 212 } 213 214 /* Free up now-unused memory */ 215 static void free_sec(unsigned long start, unsigned long end, const char *name) 216 { 217 unsigned long cnt = 0; 218 219 while (start < end) { 220 ClearPageReserved(virt_to_page(start)); 221 init_page_count(virt_to_page(start)); 222 free_page(start); 223 cnt++; 224 start += PAGE_SIZE; 225 } 226 if (cnt) { 227 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name); 228 totalram_pages += cnt; 229 } 230 } 231 232 void free_initmem(void) 233 { 234 #define FREESEC(TYPE) \ 235 free_sec((unsigned long)(&__ ## TYPE ## _begin), \ 236 (unsigned long)(&__ ## TYPE ## _end), \ 237 #TYPE); 238 239 printk ("Freeing unused kernel memory:"); 240 FREESEC(init); 241 printk("\n"); 242 ppc_md.progress = NULL; 243 #undef FREESEC 244 } 245 246 #ifdef CONFIG_BLK_DEV_INITRD 247 void free_initrd_mem(unsigned long start, unsigned long end) 248 { 249 if (start < end) 250 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10); 251 for (; start < end; start += PAGE_SIZE) { 252 ClearPageReserved(virt_to_page(start)); 253 init_page_count(virt_to_page(start)); 254 free_page(start); 255 totalram_pages++; 256 } 257 } 258 #endif 259