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
  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