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 * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk). 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 * This program is free software; you can redistribute it and/or 15 * modify it under the terms of the GNU General Public License 16 * as published by the Free Software Foundation; either version 17 * 2 of the License, or (at your option) any later version. 18 * 19 */ 20 21 #include <linux/module.h> 22 #include <linux/sched.h> 23 #include <linux/kernel.h> 24 #include <linux/errno.h> 25 #include <linux/string.h> 26 #include <linux/types.h> 27 #include <linux/mm.h> 28 #include <linux/stddef.h> 29 #include <linux/init.h> 30 #include <linux/bootmem.h> 31 #include <linux/highmem.h> 32 #include <linux/initrd.h> 33 #include <linux/pagemap.h> 34 35 #include <asm/pgalloc.h> 36 #include <asm/prom.h> 37 #include <asm/io.h> 38 #include <asm/mmu_context.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/prom.h> 46 #include <asm/lmb.h> 47 #include <asm/sections.h> 48 49 #include "mmu_decl.h" 50 51 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL) 52 /* The ammount of lowmem must be within 0xF0000000 - KERNELBASE. */ 53 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - KERNELBASE)) 54 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL" 55 #endif 56 #endif 57 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE 58 59 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); 60 61 unsigned long total_memory; 62 unsigned long total_lowmem; 63 64 unsigned long ppc_memstart; 65 unsigned long ppc_memoffset = PAGE_OFFSET; 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 #ifdef CONFIG_HIGHMEM 74 pte_t *kmap_pte; 75 pgprot_t kmap_prot; 76 77 EXPORT_SYMBOL(kmap_prot); 78 EXPORT_SYMBOL(kmap_pte); 79 #endif 80 81 void MMU_init(void); 82 83 /* XXX should be in current.h -- paulus */ 84 extern struct task_struct *current_set[NR_CPUS]; 85 86 extern int init_bootmem_done; 87 88 /* 89 * this tells the system to map all of ram with the segregs 90 * (i.e. page tables) instead of the bats. 91 * -- Cort 92 */ 93 int __map_without_bats; 94 int __map_without_ltlbs; 95 96 /* max amount of low RAM to map in */ 97 unsigned long __max_low_memory = MAX_LOW_MEM; 98 99 /* 100 * limit of what is accessible with initial MMU setup - 101 * 256MB usually, but only 16MB on 601. 102 */ 103 unsigned long __initial_memory_limit = 0x10000000; 104 105 /* 106 * Check for command-line options that affect what MMU_init will do. 107 */ 108 void MMU_setup(void) 109 { 110 /* Check for nobats option (used in mapin_ram). */ 111 if (strstr(cmd_line, "nobats")) { 112 __map_without_bats = 1; 113 } 114 115 if (strstr(cmd_line, "noltlbs")) { 116 __map_without_ltlbs = 1; 117 } 118 } 119 120 /* 121 * MMU_init sets up the basic memory mappings for the kernel, 122 * including both RAM and possibly some I/O regions, 123 * and sets up the page tables and the MMU hardware ready to go. 124 */ 125 void __init MMU_init(void) 126 { 127 if (ppc_md.progress) 128 ppc_md.progress("MMU:enter", 0x111); 129 130 /* 601 can only access 16MB at the moment */ 131 if (PVR_VER(mfspr(SPRN_PVR)) == 1) 132 __initial_memory_limit = 0x01000000; 133 134 /* parse args from command line */ 135 MMU_setup(); 136 137 if (lmb.memory.cnt > 1) { 138 lmb.memory.cnt = 1; 139 lmb_analyze(); 140 printk(KERN_WARNING "Only using first contiguous memory region"); 141 } 142 143 total_memory = lmb_end_of_DRAM(); 144 total_lowmem = total_memory; 145 146 #ifdef CONFIG_FSL_BOOKE 147 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 148 * entries, so we need to adjust lowmem to match the amount we can map 149 * in the fixed entries */ 150 adjust_total_lowmem(); 151 #endif /* CONFIG_FSL_BOOKE */ 152 153 if (total_lowmem > __max_low_memory) { 154 total_lowmem = __max_low_memory; 155 #ifndef CONFIG_HIGHMEM 156 total_memory = total_lowmem; 157 lmb_enforce_memory_limit(total_lowmem); 158 lmb_analyze(); 159 #endif /* CONFIG_HIGHMEM */ 160 } 161 162 /* Initialize the MMU hardware */ 163 if (ppc_md.progress) 164 ppc_md.progress("MMU:hw init", 0x300); 165 MMU_init_hw(); 166 167 /* Map in all of RAM starting at KERNELBASE */ 168 if (ppc_md.progress) 169 ppc_md.progress("MMU:mapin", 0x301); 170 mapin_ram(); 171 172 #ifdef CONFIG_HIGHMEM 173 ioremap_base = PKMAP_BASE; 174 #else 175 ioremap_base = 0xfe000000UL; /* for now, could be 0xfffff000 */ 176 #endif /* CONFIG_HIGHMEM */ 177 ioremap_bot = ioremap_base; 178 179 /* Map in I/O resources */ 180 if (ppc_md.progress) 181 ppc_md.progress("MMU:setio", 0x302); 182 if (ppc_md.setup_io_mappings) 183 ppc_md.setup_io_mappings(); 184 185 /* Initialize the context management stuff */ 186 mmu_context_init(); 187 188 if (ppc_md.progress) 189 ppc_md.progress("MMU:exit", 0x211); 190 191 /* From now on, btext is no longer BAT mapped if it was at all */ 192 #ifdef CONFIG_BOOTX_TEXT 193 btext_unmap(); 194 #endif 195 } 196 197 /* This is only called until mem_init is done. */ 198 void __init *early_get_page(void) 199 { 200 void *p; 201 202 if (init_bootmem_done) { 203 p = alloc_bootmem_pages(PAGE_SIZE); 204 } else { 205 p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE, 206 __initial_memory_limit)); 207 } 208 return p; 209 } 210 211 /* Free up now-unused memory */ 212 static void free_sec(unsigned long start, unsigned long end, const char *name) 213 { 214 unsigned long cnt = 0; 215 216 while (start < end) { 217 ClearPageReserved(virt_to_page(start)); 218 init_page_count(virt_to_page(start)); 219 free_page(start); 220 cnt++; 221 start += PAGE_SIZE; 222 } 223 if (cnt) { 224 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name); 225 totalram_pages += cnt; 226 } 227 } 228 229 void free_initmem(void) 230 { 231 #define FREESEC(TYPE) \ 232 free_sec((unsigned long)(&__ ## TYPE ## _begin), \ 233 (unsigned long)(&__ ## TYPE ## _end), \ 234 #TYPE); 235 236 printk ("Freeing unused kernel memory:"); 237 FREESEC(init); 238 printk("\n"); 239 ppc_md.progress = NULL; 240 #undef FREESEC 241 } 242 243 #ifdef CONFIG_BLK_DEV_INITRD 244 void free_initrd_mem(unsigned long start, unsigned long end) 245 { 246 if (start < end) 247 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10); 248 for (; start < end; start += PAGE_SIZE) { 249 ClearPageReserved(virt_to_page(start)); 250 init_page_count(virt_to_page(start)); 251 free_page(start); 252 totalram_pages++; 253 } 254 } 255 #endif 256