arch/xtensa/mm/init.c

   1 /*
   2  * arch/xtensa/mm/init.c
   3  *
   4  * Derived from MIPS, PPC.
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  *
  10  * Copyright (C) 2001 - 2005 Tensilica Inc.
  11  *
  12  * Chris Zankel <chris@zankel.net>
  13  * Joe Taylor   <joe@tensilica.com, joetylr@yahoo.com>
  14  * Marc Gauthier
  15  * Kevin Chea
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/errno.h>
  20 #include <linux/bootmem.h>
  21 #include <linux/swap.h>
  22 #include <linux/mman.h>
  23 #include <linux/nodemask.h>
  24 #include <linux/mm.h>
  25 #include <linux/slab.h>
  26
  27 #include <asm/pgtable.h>
  28 #include <asm/bootparam.h>
  29 #include <asm/mmu_context.h>
  30 #include <asm/tlb.h>
  31 #include <asm/page.h>
  32 #include <asm/pgalloc.h>
  33
  34
  35 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  36
  37 /* References to section boundaries */
  38
  39 extern char _ftext, _etext, _fdata, _edata, _rodata_end;
  40 extern char __init_begin, __init_end;
  41
  42 /*
  43  * mem_reserve(start, end, must_exist)
  44  *
  45  * Reserve some memory from the memory pool.
  46  *
  47  * Parameters:
  48  *  start       Start of region,
  49  *  end         End of region,
  50  *  must_exist  Must exist in memory pool.
  51  *
  52  * Returns:
  53  *  0 (memory area couldn't be mapped)
  54  * -1 (success)
  55  */
  56
  57 int __init mem_reserve(unsigned long start, unsigned long end, int must_exist)
  58 {
  59         int i;
  60
  61         if (start == end)
  62                 return 0;
  63
  64         start = start & PAGE_MASK;
  65         end = PAGE_ALIGN(end);
  66
  67         for (i = 0; i < sysmem.nr_banks; i++)
  68                 if (start < sysmem.bank[i].end
  69                     && end >= sysmem.bank[i].start)
  70                         break;
  71
  72         if (i == sysmem.nr_banks) {
  73                 if (must_exist)
  74                         printk (KERN_WARNING "mem_reserve: [0x%0lx, 0x%0lx) "
  75                                 "not in any region!\n", start, end);
  76                 return 0;
  77         }
  78
  79         if (start > sysmem.bank[i].start) {
  80                 if (end < sysmem.bank[i].end) {
  81                         /* split entry */
  82                         if (sysmem.nr_banks >= SYSMEM_BANKS_MAX)
  83                                 panic("meminfo overflow\n");
  84                         sysmem.bank[sysmem.nr_banks].start = end;
  85                         sysmem.bank[sysmem.nr_banks].end = sysmem.bank[i].end;
  86                         sysmem.nr_banks++;
  87                 }
  88                 sysmem.bank[i].end = start;
  89         } else {
  90                 if (end < sysmem.bank[i].end)
  91                         sysmem.bank[i].start = end;
  92                 else {
  93                         /* remove entry */
  94                         sysmem.nr_banks--;
  95                         sysmem.bank[i].start = sysmem.bank[sysmem.nr_banks].start;
  96                         sysmem.bank[i].end   = sysmem.bank[sysmem.nr_banks].end;
  97                 }
  98         }
  99         return -1;
 100 }
 101
 102
 103 /*
 104  * Initialize the bootmem system and give it all the memory we have available.
 105  */
 106
 107 void __init bootmem_init(void)
 108 {
 109         unsigned long pfn;
 110         unsigned long bootmap_start, bootmap_size;
 111         int i;
 112
 113         max_low_pfn = max_pfn = 0;
 114         min_low_pfn = ~0;
 115
 116         for (i=0; i < sysmem.nr_banks; i++) {
 117                 pfn = PAGE_ALIGN(sysmem.bank[i].start) >> PAGE_SHIFT;
 118                 if (pfn < min_low_pfn)
 119                         min_low_pfn = pfn;
 120                 pfn = PAGE_ALIGN(sysmem.bank[i].end - 1) >> PAGE_SHIFT;
 121                 if (pfn > max_pfn)
 122                         max_pfn = pfn;
 123         }
 124
 125         if (min_low_pfn > max_pfn)
 126                 panic("No memory found!\n");
 127
 128         max_low_pfn = max_pfn < MAX_MEM_PFN >> PAGE_SHIFT ?
 129                 max_pfn : MAX_MEM_PFN >> PAGE_SHIFT;
 130
 131         /* Find an area to use for the bootmem bitmap. */
 132
 133         bootmap_size = bootmem_bootmap_pages(max_low_pfn - min_low_pfn);
 134         bootmap_size <<= PAGE_SHIFT;
 135         bootmap_start = ~0;
 136
 137         for (i=0; i<sysmem.nr_banks; i++)
 138                 if (sysmem.bank[i].end - sysmem.bank[i].start >= bootmap_size) {
 139                         bootmap_start = sysmem.bank[i].start;
 140                         break;
 141                 }
 142
 143         if (bootmap_start == ~0UL)
 144                 panic("Cannot find %ld bytes for bootmap\n", bootmap_size);
 145
 146         /* Reserve the bootmem bitmap area */
 147
 148         mem_reserve(bootmap_start, bootmap_start + bootmap_size, 1);
 149         bootmap_size = init_bootmem_node(NODE_DATA(0),
 150                                          bootmap_start >> PAGE_SHIFT,
 151                                          min_low_pfn,
 152                                          max_low_pfn);
 153
 154         /* Add all remaining memory pieces into the bootmem map */
 155
 156         for (i=0; i<sysmem.nr_banks; i++)
 157                 free_bootmem(sysmem.bank[i].start,
 158                              sysmem.bank[i].end - sysmem.bank[i].start);
 159
 160 }
 161
 162
 163 void __init paging_init(void)
 164 {
 165         unsigned long zones_size[MAX_NR_ZONES];
 166         int i;
 167
 168         /* All pages are DMA-able, so we put them all in the DMA zone. */
 169
 170         zones_size[ZONE_DMA] = max_low_pfn;
 171         for (i = 1; i < MAX_NR_ZONES; i++)
 172                 zones_size[i] = 0;
 173
 174 #ifdef CONFIG_HIGHMEM
 175         zones_size[ZONE_HIGHMEM] = max_pfn - max_low_pfn;
 176 #endif
 177
 178         /* Initialize the kernel's page tables. */
 179
 180         memset(swapper_pg_dir, 0, PAGE_SIZE);
 181
 182         free_area_init(zones_size);
 183 }
 184
 185 /*
 186  * Flush the mmu and reset associated register to default values.
 187  */
 188
 189 void __init init_mmu (void)
 190 {
 191         /* Writing zeros to the <t>TLBCFG special registers ensure
 192          * that valid values exist in the register.  For existing
 193          * PGSZID<w> fields, zero selects the first element of the
 194          * page-size array.  For nonexistent PGSZID<w> fields, zero is
 195          * the best value to write.  Also, when changing PGSZID<w>
 196          * fields, the corresponding TLB must be flushed.
 197          */
 198         set_itlbcfg_register (0);
 199         set_dtlbcfg_register (0);
 200         flush_tlb_all ();
 201
 202         /* Set rasid register to a known value. */
 203
 204         set_rasid_register (ASID_USER_FIRST);
 205
 206         /* Set PTEVADDR special register to the start of the page
 207          * table, which is in kernel mappable space (ie. not
 208          * statically mapped).  This register's value is undefined on
 209          * reset.
 210          */
 211         set_ptevaddr_register (PGTABLE_START);
 212 }
 213
 214 /*
 215  * Initialize memory pages.
 216  */
 217
 218 void __init mem_init(void)
 219 {
 220         unsigned long codesize, reservedpages, datasize, initsize;
 221         unsigned long highmemsize, tmp, ram;
 222
 223         max_mapnr = num_physpages = max_low_pfn;
 224         high_memory = (void *) __va(max_mapnr << PAGE_SHIFT);
 225         highmemsize = 0;
 226
 227 #ifdef CONFIG_HIGHMEM
 228 #error HIGHGMEM not implemented in init.c
 229 #endif
 230
 231         totalram_pages += free_all_bootmem();
 232
 233         reservedpages = ram = 0;
 234         for (tmp = 0; tmp < max_low_pfn; tmp++) {
 235                 ram++;
 236                 if (PageReserved(mem_map+tmp))
 237                         reservedpages++;
 238         }
 239
 240         codesize =  (unsigned long) &_etext - (unsigned long) &_ftext;
 241         datasize =  (unsigned long) &_edata - (unsigned long) &_fdata;
 242         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 243
 244         printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, "
 245                "%ldk data, %ldk init %ldk highmem)\n",
 246                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 247                ram << (PAGE_SHIFT-10),
 248                codesize >> 10,
 249                reservedpages << (PAGE_SHIFT-10),
 250                datasize >> 10,
 251                initsize >> 10,
 252                highmemsize >> 10);
 253 }
 254
 255 void
 256 free_reserved_mem(void *start, void *end)
 257 {
 258         for (; start < end; start += PAGE_SIZE) {
 259                 ClearPageReserved(virt_to_page(start));
 260                 init_page_count(virt_to_page(start));
 261                 free_page((unsigned long)start);
 262                 totalram_pages++;
 263         }
 264 }
 265
 266 #ifdef CONFIG_BLK_DEV_INITRD
 267 extern int initrd_is_mapped;
 268
 269 void free_initrd_mem(unsigned long start, unsigned long end)
 270 {
 271         if (initrd_is_mapped) {
 272                 free_reserved_mem((void*)start, (void*)end);
 273                 printk ("Freeing initrd memory: %ldk freed\n",(end-start)>>10);
 274         }
 275 }
 276 #endif
 277
 278 void free_initmem(void)
 279 {
 280         free_reserved_mem(&__init_begin, &__init_end);
 281         printk("Freeing unused kernel memory: %dk freed\n",
 282                (&__init_end - &__init_begin) >> 10);
 283 }
 284
 285 struct kmem_cache *pgtable_cache __read_mostly;
 286
 287 static void pgd_ctor(void* addr)
 288 {
 289         pte_t* ptep = (pte_t*)addr;
 290         int i;
 291
 292         for (i = 0; i < 1024; i++, ptep++)
 293                 pte_clear(NULL, 0, ptep);
 294
 295 }
 296
 297 void __init pgtable_cache_init(void)
 298 {
 299         pgtable_cache = kmem_cache_create("pgd",
 300                         PAGE_SIZE, PAGE_SIZE,
 301                         SLAB_HWCACHE_ALIGN,
 302                         pgd_ctor);
 303 }