arch/powerpc/mm/init_64.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  *
   9  *  Derived from "arch/i386/mm/init.c"
  10  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  11  *
  12  *  Dave Engebretsen <engebret@us.ibm.com>
  13  *      Rework for PPC64 port.
  14  *
  15  *  This program is free software; you can redistribute it and/or
  16  *  modify it under the terms of the GNU General Public License
  17  *  as published by the Free Software Foundation; either version
  18  *  2 of the License, or (at your option) any later version.
  19  *
  20  */
  21
  22 #undef DEBUG
  23
  24 #include <linux/signal.h>
  25 #include <linux/sched.h>
  26 #include <linux/kernel.h>
  27 #include <linux/errno.h>
  28 #include <linux/string.h>
  29 #include <linux/types.h>
  30 #include <linux/mman.h>
  31 #include <linux/mm.h>
  32 #include <linux/swap.h>
  33 #include <linux/stddef.h>
  34 #include <linux/vmalloc.h>
  35 #include <linux/init.h>
  36 #include <linux/delay.h>
  37 #include <linux/highmem.h>
  38 #include <linux/idr.h>
  39 #include <linux/nodemask.h>
  40 #include <linux/module.h>
  41 #include <linux/poison.h>
  42 #include <linux/memblock.h>
  43 #include <linux/hugetlb.h>
  44 #include <linux/slab.h>
  45
  46 #include <asm/pgalloc.h>
  47 #include <asm/page.h>
  48 #include <asm/prom.h>
  49 #include <asm/rtas.h>
  50 #include <asm/io.h>
  51 #include <asm/mmu_context.h>
  52 #include <asm/pgtable.h>
  53 #include <asm/mmu.h>
  54 #include <asm/uaccess.h>
  55 #include <asm/smp.h>
  56 #include <asm/machdep.h>
  57 #include <asm/tlb.h>
  58 #include <asm/eeh.h>
  59 #include <asm/processor.h>
  60 #include <asm/mmzone.h>
  61 #include <asm/cputable.h>
  62 #include <asm/sections.h>
  63 #include <asm/iommu.h>
  64 #include <asm/vdso.h>
  65
  66 #include "mmu_decl.h"
  67
  68 #ifdef CONFIG_PPC_STD_MMU_64
  69 #if PGTABLE_RANGE > USER_VSID_RANGE
  70 #warning Limited user VSID range means pagetable space is wasted
  71 #endif
  72
  73 #if (TASK_SIZE_USER64 < PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE)
  74 #warning TASK_SIZE is smaller than it needs to be.
  75 #endif
  76 #endif /* CONFIG_PPC_STD_MMU_64 */
  77
  78 phys_addr_t memstart_addr = ~0;
  79 EXPORT_SYMBOL_GPL(memstart_addr);
  80 phys_addr_t kernstart_addr;
  81 EXPORT_SYMBOL_GPL(kernstart_addr);
  82
  83 static void pgd_ctor(void *addr)
  84 {
  85         memset(addr, 0, PGD_TABLE_SIZE);
  86 }
  87
  88 static void pmd_ctor(void *addr)
  89 {
  90 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  91         memset(addr, 0, PMD_TABLE_SIZE * 2);
  92 #else
  93         memset(addr, 0, PMD_TABLE_SIZE);
  94 #endif
  95 }
  96
  97 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];
  98
  99 /*
 100  * Create a kmem_cache() for pagetables.  This is not used for PTE
 101  * pages - they're linked to struct page, come from the normal free
 102  * pages pool and have a different entry size (see real_pte_t) to
 103  * everything else.  Caches created by this function are used for all
 104  * the higher level pagetables, and for hugepage pagetables.
 105  */
 106 void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
 107 {
 108         char *name;
 109         unsigned long table_size = sizeof(void *) << shift;
 110         unsigned long align = table_size;
 111
 112         /* When batching pgtable pointers for RCU freeing, we store
 113          * the index size in the low bits.  Table alignment must be
 114          * big enough to fit it.
 115          *
 116          * Likewise, hugeapge pagetable pointers contain a (different)
 117          * shift value in the low bits.  All tables must be aligned so
 118          * as to leave enough 0 bits in the address to contain it. */
 119         unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
 120                                      HUGEPD_SHIFT_MASK + 1);
 121         struct kmem_cache *new;
 122
 123         /* It would be nice if this was a BUILD_BUG_ON(), but at the
 124          * moment, gcc doesn't seem to recognize is_power_of_2 as a
 125          * constant expression, so so much for that. */
 126         BUG_ON(!is_power_of_2(minalign));
 127         BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE));
 128
 129         if (PGT_CACHE(shift))
 130                 return; /* Already have a cache of this size */
 131
 132         align = max_t(unsigned long, align, minalign);
 133         name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
 134         new = kmem_cache_create(name, table_size, align, 0, ctor);
 135         kfree(name);
 136         pgtable_cache[shift - 1] = new;
 137         pr_debug("Allocated pgtable cache for order %d\n", shift);
 138 }
 139
 140
 141 void pgtable_cache_init(void)
 142 {
 143         pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
 144         pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor);
 145         if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_CACHE_INDEX))
 146                 panic("Couldn't allocate pgtable caches");
 147         /* In all current configs, when the PUD index exists it's the
 148          * same size as either the pgd or pmd index.  Verify that the
 149          * initialization above has also created a PUD cache.  This
 150          * will need re-examiniation if we add new possibilities for
 151          * the pagetable layout. */
 152         BUG_ON(PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE));
 153 }
 154
 155 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 156 /*
 157  * Given an address within the vmemmap, determine the pfn of the page that
 158  * represents the start of the section it is within.  Note that we have to
 159  * do this by hand as the proffered address may not be correctly aligned.
 160  * Subtraction of non-aligned pointers produces undefined results.
 161  */
 162 static unsigned long __meminit vmemmap_section_start(unsigned long page)
 163 {
 164         unsigned long offset = page - ((unsigned long)(vmemmap));
 165
 166         /* Return the pfn of the start of the section. */
 167         return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
 168 }
 169
 170 /*
 171  * Check if this vmemmap page is already initialised.  If any section
 172  * which overlaps this vmemmap page is initialised then this page is
 173  * initialised already.
 174  */
 175 static int __meminit vmemmap_populated(unsigned long start, int page_size)
 176 {
 177         unsigned long end = start + page_size;
 178         start = (unsigned long)(pfn_to_page(vmemmap_section_start(start)));
 179
 180         for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
 181                 if (pfn_valid(page_to_pfn((struct page *)start)))
 182                         return 1;
 183
 184         return 0;
 185 }
 186
 187 /* On hash-based CPUs, the vmemmap is bolted in the hash table.
 188  *
 189  * On Book3E CPUs, the vmemmap is currently mapped in the top half of
 190  * the vmalloc space using normal page tables, though the size of
 191  * pages encoded in the PTEs can be different
 192  */
 193
 194 #ifdef CONFIG_PPC_BOOK3E
 195 static void __meminit vmemmap_create_mapping(unsigned long start,
 196                                              unsigned long page_size,
 197                                              unsigned long phys)
 198 {
 199         /* Create a PTE encoding without page size */
 200         unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
 201                 _PAGE_KERNEL_RW;
 202
 203         /* PTEs only contain page size encodings up to 32M */
 204         BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
 205
 206         /* Encode the size in the PTE */
 207         flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
 208
 209         /* For each PTE for that area, map things. Note that we don't
 210          * increment phys because all PTEs are of the large size and
 211          * thus must have the low bits clear
 212          */
 213         for (i = 0; i < page_size; i += PAGE_SIZE)
 214                 BUG_ON(map_kernel_page(start + i, phys, flags));
 215 }
 216
 217 #ifdef CONFIG_MEMORY_HOTPLUG
 218 static void vmemmap_remove_mapping(unsigned long start,
 219                                    unsigned long page_size)
 220 {
 221 }
 222 #endif
 223 #else /* CONFIG_PPC_BOOK3E */
 224 static void __meminit vmemmap_create_mapping(unsigned long start,
 225                                              unsigned long page_size,
 226                                              unsigned long phys)
 227 {
 228         int  mapped = htab_bolt_mapping(start, start + page_size, phys,
 229                                         pgprot_val(PAGE_KERNEL),
 230                                         mmu_vmemmap_psize,
 231                                         mmu_kernel_ssize);
 232         BUG_ON(mapped < 0);
 233 }
 234
 235 #ifdef CONFIG_MEMORY_HOTPLUG
 236 static void vmemmap_remove_mapping(unsigned long start,
 237                                    unsigned long page_size)
 238 {
 239         int mapped = htab_remove_mapping(start, start + page_size,
 240                                          mmu_vmemmap_psize,
 241                                          mmu_kernel_ssize);
 242         BUG_ON(mapped < 0);
 243 }
 244 #endif
 245
 246 #endif /* CONFIG_PPC_BOOK3E */
 247
 248 struct vmemmap_backing *vmemmap_list;
 249 static struct vmemmap_backing *next;
 250 static int num_left;
 251 static int num_freed;
 252
 253 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node)
 254 {
 255         struct vmemmap_backing *vmem_back;
 256         /* get from freed entries first */
 257         if (num_freed) {
 258                 num_freed--;
 259                 vmem_back = next;
 260                 next = next->list;
 261
 262                 return vmem_back;
 263         }
 264
 265         /* allocate a page when required and hand out chunks */
 266         if (!num_left) {
 267                 next = vmemmap_alloc_block(PAGE_SIZE, node);
 268                 if (unlikely(!next)) {
 269                         WARN_ON(1);
 270                         return NULL;
 271                 }
 272                 num_left = PAGE_SIZE / sizeof(struct vmemmap_backing);
 273         }
 274
 275         num_left--;
 276
 277         return next++;
 278 }
 279
 280 static __meminit void vmemmap_list_populate(unsigned long phys,
 281                                             unsigned long start,
 282                                             int node)
 283 {
 284         struct vmemmap_backing *vmem_back;
 285
 286         vmem_back = vmemmap_list_alloc(node);
 287         if (unlikely(!vmem_back)) {
 288                 WARN_ON(1);
 289                 return;
 290         }
 291
 292         vmem_back->phys = phys;
 293         vmem_back->virt_addr = start;
 294         vmem_back->list = vmemmap_list;
 295
 296         vmemmap_list = vmem_back;
 297 }
 298
 299 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 300 {
 301         unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
 302
 303         /* Align to the page size of the linear mapping. */
 304         start = _ALIGN_DOWN(start, page_size);
 305
 306         pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
 307
 308         for (; start < end; start += page_size) {
 309                 void *p;
 310
 311                 if (vmemmap_populated(start, page_size))
 312                         continue;
 313
 314                 p = vmemmap_alloc_block(page_size, node);
 315                 if (!p)
 316                         return -ENOMEM;
 317
 318                 vmemmap_list_populate(__pa(p), start, node);
 319
 320                 pr_debug("      * %016lx..%016lx allocated at %p\n",
 321                          start, start + page_size, p);
 322
 323                 vmemmap_create_mapping(start, page_size, __pa(p));
 324         }
 325
 326         return 0;
 327 }
 328
 329 #ifdef CONFIG_MEMORY_HOTPLUG
 330 static unsigned long vmemmap_list_free(unsigned long start)
 331 {
 332         struct vmemmap_backing *vmem_back, *vmem_back_prev;
 333
 334         vmem_back_prev = vmem_back = vmemmap_list;
 335
 336         /* look for it with prev pointer recorded */
 337         for (; vmem_back; vmem_back = vmem_back->list) {
 338                 if (vmem_back->virt_addr == start)
 339                         break;
 340                 vmem_back_prev = vmem_back;
 341         }
 342
 343         if (unlikely(!vmem_back)) {
 344                 WARN_ON(1);
 345                 return 0;
 346         }
 347
 348         /* remove it from vmemmap_list */
 349         if (vmem_back == vmemmap_list) /* remove head */
 350                 vmemmap_list = vmem_back->list;
 351         else
 352                 vmem_back_prev->list = vmem_back->list;
 353
 354         /* next point to this freed entry */
 355         vmem_back->list = next;
 356         next = vmem_back;
 357         num_freed++;
 358
 359         return vmem_back->phys;
 360 }
 361
 362 void __ref vmemmap_free(unsigned long start, unsigned long end)
 363 {
 364         unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
 365
 366         start = _ALIGN_DOWN(start, page_size);
 367
 368         pr_debug("vmemmap_free %lx...%lx\n", start, end);
 369
 370         for (; start < end; start += page_size) {
 371                 unsigned long addr;
 372
 373                 /*
 374                  * the section has already be marked as invalid, so
 375                  * vmemmap_populated() true means some other sections still
 376                  * in this page, so skip it.
 377                  */
 378                 if (vmemmap_populated(start, page_size))
 379                         continue;
 380
 381                 addr = vmemmap_list_free(start);
 382                 if (addr) {
 383                         struct page *page = pfn_to_page(addr >> PAGE_SHIFT);
 384
 385                         if (PageReserved(page)) {
 386                                 /* allocated from bootmem */
 387                                 if (page_size < PAGE_SIZE) {
 388                                         /*
 389                                          * this shouldn't happen, but if it is
 390                                          * the case, leave the memory there
 391                                          */
 392                                         WARN_ON_ONCE(1);
 393                                 } else {
 394                                         unsigned int nr_pages =
 395                                                 1 << get_order(page_size);
 396                                         while (nr_pages--)
 397                                                 free_reserved_page(page++);
 398                                 }
 399                         } else
 400                                 free_pages((unsigned long)(__va(addr)),
 401                                                         get_order(page_size));
 402
 403                         vmemmap_remove_mapping(start, page_size);
 404                 }
 405         }
 406 }
 407 #endif
 408 void register_page_bootmem_memmap(unsigned long section_nr,
 409                                   struct page *start_page, unsigned long size)
 410 {
 411 }
 412
 413 /*
 414  * We do not have access to the sparsemem vmemmap, so we fallback to
 415  * walking the list of sparsemem blocks which we already maintain for
 416  * the sake of crashdump. In the long run, we might want to maintain
 417  * a tree if performance of that linear walk becomes a problem.
 418  *
 419  * realmode_pfn_to_page functions can fail due to:
 420  * 1) As real sparsemem blocks do not lay in RAM continously (they
 421  * are in virtual address space which is not available in the real mode),
 422  * the requested page struct can be split between blocks so get_page/put_page
 423  * may fail.
 424  * 2) When huge pages are used, the get_page/put_page API will fail
 425  * in real mode as the linked addresses in the page struct are virtual
 426  * too.
 427  */
 428 struct page *realmode_pfn_to_page(unsigned long pfn)
 429 {
 430         struct vmemmap_backing *vmem_back;
 431         struct page *page;
 432         unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
 433         unsigned long pg_va = (unsigned long) pfn_to_page(pfn);
 434
 435         for (vmem_back = vmemmap_list; vmem_back; vmem_back = vmem_back->list) {
 436                 if (pg_va < vmem_back->virt_addr)
 437                         continue;
 438
 439                 /* After vmemmap_list entry free is possible, need check all */
 440                 if ((pg_va + sizeof(struct page)) <=
 441                                 (vmem_back->virt_addr + page_size)) {
 442                         page = (struct page *) (vmem_back->phys + pg_va -
 443                                 vmem_back->virt_addr);
 444                         return page;
 445                 }
 446         }
 447
 448         /* Probably that page struct is split between real pages */
 449         return NULL;
 450 }
 451 EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
 452
 453 #elif defined(CONFIG_FLATMEM)
 454
 455 struct page *realmode_pfn_to_page(unsigned long pfn)
 456 {
 457         struct page *page = pfn_to_page(pfn);
 458         return page;
 459 }
 460 EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
 461
 462 #endif /* CONFIG_SPARSEMEM_VMEMMAP/CONFIG_FLATMEM */