arch/powerpc/mm/init_32.c

   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/lmb.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 (lmb.memory.cnt > 1) {
 140 #ifndef CONFIG_WII
 141                 lmb.memory.cnt = 1;
 142                 lmb_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 = lmb_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                 lmb_enforce_memory_limit(lowmem_end_addr);
 165                 lmb_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(lmb_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