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/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