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/config.h> 22 #include <linux/module.h> 23 #include <linux/sched.h> 24 #include <linux/kernel.h> 25 #include <linux/errno.h> 26 #include <linux/string.h> 27 #include <linux/types.h> 28 #include <linux/mm.h> 29 #include <linux/stddef.h> 30 #include <linux/init.h> 31 #include <linux/bootmem.h> 32 #include <linux/highmem.h> 33 #include <linux/initrd.h> 34 #include <linux/pagemap.h> 35 36 #include <asm/pgalloc.h> 37 #include <asm/prom.h> 38 #include <asm/io.h> 39 #include <asm/mmu_context.h> 40 #include <asm/pgtable.h> 41 #include <asm/mmu.h> 42 #include <asm/smp.h> 43 #include <asm/machdep.h> 44 #include <asm/btext.h> 45 #include <asm/tlb.h> 46 #include <asm/prom.h> 47 #include <asm/lmb.h> 48 #include <asm/sections.h> 49 50 #include "mmu_decl.h" 51 52 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL) 53 /* The ammount of lowmem must be within 0xF0000000 - KERNELBASE. */ 54 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - KERNELBASE)) 55 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL" 56 #endif 57 #endif 58 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE 59 60 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); 61 62 unsigned long total_memory; 63 unsigned long total_lowmem; 64 65 unsigned long ppc_memstart; 66 unsigned long ppc_memoffset = PAGE_OFFSET; 67 68 int boot_mapsize; 69 #ifdef CONFIG_PPC_PMAC 70 unsigned long agp_special_page; 71 EXPORT_SYMBOL(agp_special_page); 72 #endif 73 74 #ifdef CONFIG_HIGHMEM 75 pte_t *kmap_pte; 76 pgprot_t kmap_prot; 77 78 EXPORT_SYMBOL(kmap_prot); 79 EXPORT_SYMBOL(kmap_pte); 80 #endif 81 82 void MMU_init(void); 83 84 /* XXX should be in current.h -- paulus */ 85 extern struct task_struct *current_set[NR_CPUS]; 86 87 extern int init_bootmem_done; 88 89 /* 90 * this tells the system to map all of ram with the segregs 91 * (i.e. page tables) instead of the bats. 92 * -- Cort 93 */ 94 int __map_without_bats; 95 int __map_without_ltlbs; 96 97 /* max amount of low RAM to map in */ 98 unsigned long __max_low_memory = MAX_LOW_MEM; 99 100 /* 101 * limit of what is accessible with initial MMU setup - 102 * 256MB usually, but only 16MB on 601. 103 */ 104 unsigned long __initial_memory_limit = 0x10000000; 105 106 /* 107 * Check for command-line options that affect what MMU_init will do. 108 */ 109 void MMU_setup(void) 110 { 111 /* Check for nobats option (used in mapin_ram). */ 112 if (strstr(cmd_line, "nobats")) { 113 __map_without_bats = 1; 114 } 115 116 if (strstr(cmd_line, "noltlbs")) { 117 __map_without_ltlbs = 1; 118 } 119 } 120 121 /* 122 * MMU_init sets up the basic memory mappings for the kernel, 123 * including both RAM and possibly some I/O regions, 124 * and sets up the page tables and the MMU hardware ready to go. 125 */ 126 void __init MMU_init(void) 127 { 128 if (ppc_md.progress) 129 ppc_md.progress("MMU:enter", 0x111); 130 131 /* 601 can only access 16MB at the moment */ 132 if (PVR_VER(mfspr(SPRN_PVR)) == 1) 133 __initial_memory_limit = 0x01000000; 134 135 /* parse args from command line */ 136 MMU_setup(); 137 138 if (lmb.memory.cnt > 1) { 139 lmb.memory.cnt = 1; 140 lmb_analyze(); 141 printk(KERN_WARNING "Only using first contiguous memory region"); 142 } 143 144 total_memory = lmb_end_of_DRAM(); 145 total_lowmem = total_memory; 146 147 #ifdef CONFIG_FSL_BOOKE 148 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB 149 * entries, so we need to adjust lowmem to match the amount we can map 150 * in the fixed entries */ 151 adjust_total_lowmem(); 152 #endif /* CONFIG_FSL_BOOKE */ 153 154 if (total_lowmem > __max_low_memory) { 155 total_lowmem = __max_low_memory; 156 #ifndef CONFIG_HIGHMEM 157 total_memory = total_lowmem; 158 lmb_enforce_memory_limit(total_lowmem); 159 lmb_analyze(); 160 #endif /* CONFIG_HIGHMEM */ 161 } 162 163 /* Initialize the MMU hardware */ 164 if (ppc_md.progress) 165 ppc_md.progress("MMU:hw init", 0x300); 166 MMU_init_hw(); 167 168 /* Map in all of RAM starting at KERNELBASE */ 169 if (ppc_md.progress) 170 ppc_md.progress("MMU:mapin", 0x301); 171 mapin_ram(); 172 173 #ifdef CONFIG_HIGHMEM 174 ioremap_base = PKMAP_BASE; 175 #else 176 ioremap_base = 0xfe000000UL; /* for now, could be 0xfffff000 */ 177 #endif /* CONFIG_HIGHMEM */ 178 ioremap_bot = ioremap_base; 179 180 /* Map in I/O resources */ 181 if (ppc_md.progress) 182 ppc_md.progress("MMU:setio", 0x302); 183 if (ppc_md.setup_io_mappings) 184 ppc_md.setup_io_mappings(); 185 186 /* Initialize the context management stuff */ 187 mmu_context_init(); 188 189 if (ppc_md.progress) 190 ppc_md.progress("MMU:exit", 0x211); 191 192 /* From now on, btext is no longer BAT mapped if it was at all */ 193 #ifdef CONFIG_BOOTX_TEXT 194 btext_unmap(); 195 #endif 196 } 197 198 /* This is only called until mem_init is done. */ 199 void __init *early_get_page(void) 200 { 201 void *p; 202 203 if (init_bootmem_done) { 204 p = alloc_bootmem_pages(PAGE_SIZE); 205 } else { 206 p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE, 207 __initial_memory_limit)); 208 } 209 return p; 210 } 211 212 /* Free up now-unused memory */ 213 static void free_sec(unsigned long start, unsigned long end, const char *name) 214 { 215 unsigned long cnt = 0; 216 217 while (start < end) { 218 ClearPageReserved(virt_to_page(start)); 219 set_page_count(virt_to_page(start), 1); 220 free_page(start); 221 cnt++; 222 start += PAGE_SIZE; 223 } 224 if (cnt) { 225 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name); 226 totalram_pages += cnt; 227 } 228 } 229 230 void free_initmem(void) 231 { 232 #define FREESEC(TYPE) \ 233 free_sec((unsigned long)(&__ ## TYPE ## _begin), \ 234 (unsigned long)(&__ ## TYPE ## _end), \ 235 #TYPE); 236 237 printk ("Freeing unused kernel memory:"); 238 FREESEC(init); 239 printk("\n"); 240 ppc_md.progress = NULL; 241 #undef FREESEC 242 } 243 244 #ifdef CONFIG_BLK_DEV_INITRD 245 void free_initrd_mem(unsigned long start, unsigned long end) 246 { 247 if (start < end) 248 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10); 249 for (; start < end; start += PAGE_SIZE) { 250 ClearPageReserved(virt_to_page(start)); 251 set_page_count(virt_to_page(start), 1); 252 free_page(start); 253 totalram_pages++; 254 } 255 } 256 #endif 257