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/lmb.h>
  45 #include <asm/sections.h>
  46
  47 #include "mmu_decl.h"
  48
  49 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
  50 /* The ammount of lowmem must be within 0xF0000000 - KERNELBASE. */
  51 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - KERNELBASE))
  52 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
  53 #endif
  54 #endif
  55 #define MAX_LOW_MEM     CONFIG_LOWMEM_SIZE
  56
  57 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  58
  59 unsigned long total_memory;
  60 unsigned long total_lowmem;
  61
  62 unsigned long ppc_memstart;
  63 unsigned long ppc_memoffset = PAGE_OFFSET;
  64
  65 int boot_mapsize;
  66 #ifdef CONFIG_PPC_PMAC
  67 unsigned long agp_special_page;
  68 EXPORT_SYMBOL(agp_special_page);
  69 #endif
  70
  71 #ifdef CONFIG_HIGHMEM
  72 pte_t *kmap_pte;
  73 pgprot_t kmap_prot;
  74
  75 EXPORT_SYMBOL(kmap_prot);
  76 EXPORT_SYMBOL(kmap_pte);
  77 #endif
  78
  79 void MMU_init(void);
  80
  81 /* XXX should be in current.h  -- paulus */
  82 extern struct task_struct *current_set[NR_CPUS];
  83
  84 extern int init_bootmem_done;
  85
  86 /*
  87  * this tells the system to map all of ram with the segregs
  88  * (i.e. page tables) instead of the bats.
  89  * -- Cort
  90  */
  91 int __map_without_bats;
  92 int __map_without_ltlbs;
  93
  94 /* max amount of low RAM to map in */
  95 unsigned long __max_low_memory = MAX_LOW_MEM;
  96
  97 /*
  98  * limit of what is accessible with initial MMU setup -
  99  * 256MB usually, but only 16MB on 601.
 100  */
 101 unsigned long __initial_memory_limit = 0x10000000;
 102
 103 /*
 104  * Check for command-line options that affect what MMU_init will do.
 105  */
 106 void MMU_setup(void)
 107 {
 108         /* Check for nobats option (used in mapin_ram). */
 109         if (strstr(cmd_line, "nobats")) {
 110                 __map_without_bats = 1;
 111         }
 112
 113         if (strstr(cmd_line, "noltlbs")) {
 114                 __map_without_ltlbs = 1;
 115         }
 116 #ifdef CONFIG_DEBUG_PAGEALLOC
 117         __map_without_bats = 1;
 118         __map_without_ltlbs = 1;
 119 #endif
 120 }
 121
 122 /*
 123  * MMU_init sets up the basic memory mappings for the kernel,
 124  * including both RAM and possibly some I/O regions,
 125  * and sets up the page tables and the MMU hardware ready to go.
 126  */
 127 void __init MMU_init(void)
 128 {
 129         if (ppc_md.progress)
 130                 ppc_md.progress("MMU:enter", 0x111);
 131
 132         /* 601 can only access 16MB at the moment */
 133         if (PVR_VER(mfspr(SPRN_PVR)) == 1)
 134                 __initial_memory_limit = 0x01000000;
 135         /* 8xx can only access 8MB at the moment */
 136         if (PVR_VER(mfspr(SPRN_PVR)) == 0x50)
 137                 __initial_memory_limit = 0x00800000;
 138
 139         /* parse args from command line */
 140         MMU_setup();
 141
 142         if (lmb.memory.cnt > 1) {
 143                 lmb.memory.cnt = 1;
 144                 lmb_analyze();
 145                 printk(KERN_WARNING "Only using first contiguous memory region");
 146         }
 147
 148         total_memory = lmb_end_of_DRAM();
 149         total_lowmem = total_memory;
 150
 151 #ifdef CONFIG_FSL_BOOKE
 152         /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
 153          * entries, so we need to adjust lowmem to match the amount we can map
 154          * in the fixed entries */
 155         adjust_total_lowmem();
 156 #endif /* CONFIG_FSL_BOOKE */
 157
 158         if (total_lowmem > __max_low_memory) {
 159                 total_lowmem = __max_low_memory;
 160 #ifndef CONFIG_HIGHMEM
 161                 total_memory = total_lowmem;
 162                 lmb_enforce_memory_limit(total_lowmem);
 163                 lmb_analyze();
 164 #endif /* CONFIG_HIGHMEM */
 165         }
 166
 167         /* Initialize the MMU hardware */
 168         if (ppc_md.progress)
 169                 ppc_md.progress("MMU:hw init", 0x300);
 170         MMU_init_hw();
 171
 172         /* Map in all of RAM starting at KERNELBASE */
 173         if (ppc_md.progress)
 174                 ppc_md.progress("MMU:mapin", 0x301);
 175         mapin_ram();
 176
 177 #ifdef CONFIG_HIGHMEM
 178         ioremap_base = PKMAP_BASE;
 179 #else
 180         ioremap_base = 0xfe000000UL;    /* for now, could be 0xfffff000 */
 181 #endif /* CONFIG_HIGHMEM */
 182         ioremap_bot = ioremap_base;
 183
 184         /* Map in I/O resources */
 185         if (ppc_md.progress)
 186                 ppc_md.progress("MMU:setio", 0x302);
 187         if (ppc_md.setup_io_mappings)
 188                 ppc_md.setup_io_mappings();
 189
 190         /* Initialize the context management stuff */
 191         mmu_context_init();
 192
 193         if (ppc_md.progress)
 194                 ppc_md.progress("MMU:exit", 0x211);
 195
 196         /* From now on, btext is no longer BAT mapped if it was at all */
 197 #ifdef CONFIG_BOOTX_TEXT
 198         btext_unmap();
 199 #endif
 200 }
 201
 202 /* This is only called until mem_init is done. */
 203 void __init *early_get_page(void)
 204 {
 205         void *p;
 206
 207         if (init_bootmem_done) {
 208                 p = alloc_bootmem_pages(PAGE_SIZE);
 209         } else {
 210                 p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
 211                                         __initial_memory_limit));
 212         }
 213         return p;
 214 }
 215
 216 /* Free up now-unused memory */
 217 static void free_sec(unsigned long start, unsigned long end, const char *name)
 218 {
 219         unsigned long cnt = 0;
 220
 221         while (start < end) {
 222                 ClearPageReserved(virt_to_page(start));
 223                 init_page_count(virt_to_page(start));
 224                 free_page(start);
 225                 cnt++;
 226                 start += PAGE_SIZE;
 227         }
 228         if (cnt) {
 229                 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
 230                 totalram_pages += cnt;
 231         }
 232 }
 233
 234 void free_initmem(void)
 235 {
 236 #define FREESEC(TYPE) \
 237         free_sec((unsigned long)(&__ ## TYPE ## _begin), \
 238                  (unsigned long)(&__ ## TYPE ## _end), \
 239                  #TYPE);
 240
 241         printk ("Freeing unused kernel memory:");
 242         FREESEC(init);
 243         printk("\n");
 244         ppc_md.progress = NULL;
 245 #undef FREESEC
 246 }
 247
 248 #ifdef CONFIG_BLK_DEV_INITRD
 249 void free_initrd_mem(unsigned long start, unsigned long end)
 250 {
 251         if (start < end)
 252                 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 253         for (; start < end; start += PAGE_SIZE) {
 254                 ClearPageReserved(virt_to_page(start));
 255                 init_page_count(virt_to_page(start));
 256                 free_page(start);
 257                 totalram_pages++;
 258         }
 259 }
 260 #endif
 261
 262 #ifdef CONFIG_PROC_KCORE
 263 static struct kcore_list kcore_vmem;
 264
 265 static int __init setup_kcore(void)
 266 {
 267         int i;
 268
 269         for (i = 0; i < lmb.memory.cnt; i++) {
 270                 unsigned long base;
 271                 unsigned long size;
 272                 struct kcore_list *kcore_mem;
 273
 274                 base = lmb.memory.region[i].base;
 275                 size = lmb.memory.region[i].size;
 276
 277                 kcore_mem = kmalloc(sizeof(struct kcore_list), GFP_ATOMIC);
 278                 if (!kcore_mem)
 279                         panic("%s: kmalloc failed\n", __FUNCTION__);
 280
 281                 /* must stay under 32 bits */
 282                 if ( 0xfffffffful - (unsigned long)__va(base) < size) {
 283                         size = 0xfffffffful - (unsigned long)(__va(base));
 284                         printk(KERN_DEBUG "setup_kcore: restrict size=%lx\n",
 285                                                 size);
 286                 }
 287
 288                 kclist_add(kcore_mem, __va(base), size);
 289         }
 290
 291         kclist_add(&kcore_vmem, (void *)VMALLOC_START,
 292                 VMALLOC_END-VMALLOC_START);
 293
 294         return 0;
 295 }
 296 module_init(setup_kcore);
 297 #endif