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  *  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