arch/powerpc/mm/hash_utils_64.c

   1 /*
   2  * PowerPC64 port by Mike Corrigan and Dave Engebretsen
   3  *   {mikejc|engebret}@us.ibm.com
   4  *
   5  *    Copyright (c) 2000 Mike Corrigan <mikejc@us.ibm.com>
   6  *
   7  * SMP scalability work:
   8  *    Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
   9  *
  10  *    Module name: htab.c
  11  *
  12  *    Description:
  13  *      PowerPC Hashed Page Table functions
  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 #undef DEBUG
  22 #undef DEBUG_LOW
  23
  24 #include <linux/spinlock.h>
  25 #include <linux/errno.h>
  26 #include <linux/sched.h>
  27 #include <linux/proc_fs.h>
  28 #include <linux/stat.h>
  29 #include <linux/sysctl.h>
  30 #include <linux/export.h>
  31 #include <linux/ctype.h>
  32 #include <linux/cache.h>
  33 #include <linux/init.h>
  34 #include <linux/signal.h>
  35 #include <linux/memblock.h>
  36
  37 #include <asm/processor.h>
  38 #include <asm/pgtable.h>
  39 #include <asm/mmu.h>
  40 #include <asm/mmu_context.h>
  41 #include <asm/page.h>
  42 #include <asm/types.h>
  43 #include <asm/uaccess.h>
  44 #include <asm/machdep.h>
  45 #include <asm/prom.h>
  46 #include <asm/abs_addr.h>
  47 #include <asm/tlbflush.h>
  48 #include <asm/io.h>
  49 #include <asm/eeh.h>
  50 #include <asm/tlb.h>
  51 #include <asm/cacheflush.h>
  52 #include <asm/cputable.h>
  53 #include <asm/sections.h>
  54 #include <asm/spu.h>
  55 #include <asm/udbg.h>
  56 #include <asm/code-patching.h>
  57 #include <asm/fadump.h>
  58 #include <asm/firmware.h>
  59
  60 #ifdef DEBUG
  61 #define DBG(fmt...) udbg_printf(fmt)
  62 #else
  63 #define DBG(fmt...)
  64 #endif
  65
  66 #ifdef DEBUG_LOW
  67 #define DBG_LOW(fmt...) udbg_printf(fmt)
  68 #else
  69 #define DBG_LOW(fmt...)
  70 #endif
  71
  72 #define KB (1024)
  73 #define MB (1024*KB)
  74 #define GB (1024L*MB)
  75
  76 /*
  77  * Note:  pte   --> Linux PTE
  78  *        HPTE  --> PowerPC Hashed Page Table Entry
  79  *
  80  * Execution context:
  81  *   htab_initialize is called with the MMU off (of course), but
  82  *   the kernel has been copied down to zero so it can directly
  83  *   reference global data.  At this point it is very difficult
  84  *   to print debug info.
  85  *
  86  */
  87
  88 #ifdef CONFIG_U3_DART
  89 extern unsigned long dart_tablebase;
  90 #endif /* CONFIG_U3_DART */
  91
  92 static unsigned long _SDR1;
  93 struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
  94
  95 struct hash_pte *htab_address;
  96 unsigned long htab_size_bytes;
  97 unsigned long htab_hash_mask;
  98 EXPORT_SYMBOL_GPL(htab_hash_mask);
  99 int mmu_linear_psize = MMU_PAGE_4K;
 100 int mmu_virtual_psize = MMU_PAGE_4K;
 101 int mmu_vmalloc_psize = MMU_PAGE_4K;
 102 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 103 int mmu_vmemmap_psize = MMU_PAGE_4K;
 104 #endif
 105 int mmu_io_psize = MMU_PAGE_4K;
 106 int mmu_kernel_ssize = MMU_SEGSIZE_256M;
 107 int mmu_highuser_ssize = MMU_SEGSIZE_256M;
 108 u16 mmu_slb_size = 64;
 109 EXPORT_SYMBOL_GPL(mmu_slb_size);
 110 #ifdef CONFIG_PPC_64K_PAGES
 111 int mmu_ci_restrictions;
 112 #endif
 113 #ifdef CONFIG_DEBUG_PAGEALLOC
 114 static u8 *linear_map_hash_slots;
 115 static unsigned long linear_map_hash_count;
 116 static DEFINE_SPINLOCK(linear_map_hash_lock);
 117 #endif /* CONFIG_DEBUG_PAGEALLOC */
 118
 119 /* There are definitions of page sizes arrays to be used when none
 120  * is provided by the firmware.
 121  */
 122
 123 /* Pre-POWER4 CPUs (4k pages only)
 124  */
 125 static struct mmu_psize_def mmu_psize_defaults_old[] = {
 126         [MMU_PAGE_4K] = {
 127                 .shift  = 12,
 128                 .sllp   = 0,
 129                 .penc   = 0,
 130                 .avpnm  = 0,
 131                 .tlbiel = 0,
 132         },
 133 };
 134
 135 /* POWER4, GPUL, POWER5
 136  *
 137  * Support for 16Mb large pages
 138  */
 139 static struct mmu_psize_def mmu_psize_defaults_gp[] = {
 140         [MMU_PAGE_4K] = {
 141                 .shift  = 12,
 142                 .sllp   = 0,
 143                 .penc   = 0,
 144                 .avpnm  = 0,
 145                 .tlbiel = 1,
 146         },
 147         [MMU_PAGE_16M] = {
 148                 .shift  = 24,
 149                 .sllp   = SLB_VSID_L,
 150                 .penc   = 0,
 151                 .avpnm  = 0x1UL,
 152                 .tlbiel = 0,
 153         },
 154 };
 155
 156 static unsigned long htab_convert_pte_flags(unsigned long pteflags)
 157 {
 158         unsigned long rflags = pteflags & 0x1fa;
 159
 160         /* _PAGE_EXEC -> NOEXEC */
 161         if ((pteflags & _PAGE_EXEC) == 0)
 162                 rflags |= HPTE_R_N;
 163
 164         /* PP bits. PAGE_USER is already PP bit 0x2, so we only
 165          * need to add in 0x1 if it's a read-only user page
 166          */
 167         if ((pteflags & _PAGE_USER) && !((pteflags & _PAGE_RW) &&
 168                                          (pteflags & _PAGE_DIRTY)))
 169                 rflags |= 1;
 170
 171         /* Always add C */
 172         return rflags | HPTE_R_C;
 173 }
 174
 175 int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 176                       unsigned long pstart, unsigned long prot,
 177                       int psize, int ssize)
 178 {
 179         unsigned long vaddr, paddr;
 180         unsigned int step, shift;
 181         int ret = 0;
 182
 183         shift = mmu_psize_defs[psize].shift;
 184         step = 1 << shift;
 185
 186         prot = htab_convert_pte_flags(prot);
 187
 188         DBG("htab_bolt_mapping(%lx..%lx -> %lx (%lx,%d,%d)\n",
 189             vstart, vend, pstart, prot, psize, ssize);
 190
 191         for (vaddr = vstart, paddr = pstart; vaddr < vend;
 192              vaddr += step, paddr += step) {
 193                 unsigned long hash, hpteg;
 194                 unsigned long vsid = get_kernel_vsid(vaddr, ssize);
 195                 unsigned long va = hpt_va(vaddr, vsid, ssize);
 196                 unsigned long tprot = prot;
 197
 198                 /* Make kernel text executable */
 199                 if (overlaps_kernel_text(vaddr, vaddr + step))
 200                         tprot &= ~HPTE_R_N;
 201
 202                 hash = hpt_hash(va, shift, ssize);
 203                 hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
 204
 205                 BUG_ON(!ppc_md.hpte_insert);
 206                 ret = ppc_md.hpte_insert(hpteg, va, paddr, tprot,
 207                                          HPTE_V_BOLTED, psize, ssize);
 208
 209                 if (ret < 0)
 210                         break;
 211 #ifdef CONFIG_DEBUG_PAGEALLOC
 212                 if ((paddr >> PAGE_SHIFT) < linear_map_hash_count)
 213                         linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80;
 214 #endif /* CONFIG_DEBUG_PAGEALLOC */
 215         }
 216         return ret < 0 ? ret : 0;
 217 }
 218
 219 #ifdef CONFIG_MEMORY_HOTPLUG
 220 static int htab_remove_mapping(unsigned long vstart, unsigned long vend,
 221                       int psize, int ssize)
 222 {
 223         unsigned long vaddr;
 224         unsigned int step, shift;
 225
 226         shift = mmu_psize_defs[psize].shift;
 227         step = 1 << shift;
 228
 229         if (!ppc_md.hpte_removebolted) {
 230                 printk(KERN_WARNING "Platform doesn't implement "
 231                                 "hpte_removebolted\n");
 232                 return -EINVAL;
 233         }
 234
 235         for (vaddr = vstart; vaddr < vend; vaddr += step)
 236                 ppc_md.hpte_removebolted(vaddr, psize, ssize);
 237
 238         return 0;
 239 }
 240 #endif /* CONFIG_MEMORY_HOTPLUG */
 241
 242 static int __init htab_dt_scan_seg_sizes(unsigned long node,
 243                                          const char *uname, int depth,
 244                                          void *data)
 245 {
 246         char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 247         u32 *prop;
 248         unsigned long size = 0;
 249
 250         /* We are scanning "cpu" nodes only */
 251         if (type == NULL || strcmp(type, "cpu") != 0)
 252                 return 0;
 253
 254         prop = (u32 *)of_get_flat_dt_prop(node, "ibm,processor-segment-sizes",
 255                                           &size);
 256         if (prop == NULL)
 257                 return 0;
 258         for (; size >= 4; size -= 4, ++prop) {
 259                 if (prop[0] == 40) {
 260                         DBG("1T segment support detected\n");
 261                         cur_cpu_spec->mmu_features |= MMU_FTR_1T_SEGMENT;
 262                         return 1;
 263                 }
 264         }
 265         cur_cpu_spec->mmu_features &= ~MMU_FTR_NO_SLBIE_B;
 266         return 0;
 267 }
 268
 269 static void __init htab_init_seg_sizes(void)
 270 {
 271         of_scan_flat_dt(htab_dt_scan_seg_sizes, NULL);
 272 }
 273
 274 static int __init htab_dt_scan_page_sizes(unsigned long node,
 275                                           const char *uname, int depth,
 276                                           void *data)
 277 {
 278         char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 279         u32 *prop;
 280         unsigned long size = 0;
 281
 282         /* We are scanning "cpu" nodes only */
 283         if (type == NULL || strcmp(type, "cpu") != 0)
 284                 return 0;
 285
 286         prop = (u32 *)of_get_flat_dt_prop(node,
 287                                           "ibm,segment-page-sizes", &size);
 288         if (prop != NULL) {
 289                 DBG("Page sizes from device-tree:\n");
 290                 size /= 4;
 291                 cur_cpu_spec->mmu_features &= ~(MMU_FTR_16M_PAGE);
 292                 while(size > 0) {
 293                         unsigned int shift = prop[0];
 294                         unsigned int slbenc = prop[1];
 295                         unsigned int lpnum = prop[2];
 296                         unsigned int lpenc = 0;
 297                         struct mmu_psize_def *def;
 298                         int idx = -1;
 299
 300                         size -= 3; prop += 3;
 301                         while(size > 0 && lpnum) {
 302                                 if (prop[0] == shift)
 303                                         lpenc = prop[1];
 304                                 prop += 2; size -= 2;
 305                                 lpnum--;
 306                         }
 307                         switch(shift) {
 308                         case 0xc:
 309                                 idx = MMU_PAGE_4K;
 310                                 break;
 311                         case 0x10:
 312                                 idx = MMU_PAGE_64K;
 313                                 break;
 314                         case 0x14:
 315                                 idx = MMU_PAGE_1M;
 316                                 break;
 317                         case 0x18:
 318                                 idx = MMU_PAGE_16M;
 319                                 cur_cpu_spec->mmu_features |= MMU_FTR_16M_PAGE;
 320                                 break;
 321                         case 0x22:
 322                                 idx = MMU_PAGE_16G;
 323                                 break;
 324                         }
 325                         if (idx < 0)
 326                                 continue;
 327                         def = &mmu_psize_defs[idx];
 328                         def->shift = shift;
 329                         if (shift <= 23)
 330                                 def->avpnm = 0;
 331                         else
 332                                 def->avpnm = (1 << (shift - 23)) - 1;
 333                         def->sllp = slbenc;
 334                         def->penc = lpenc;
 335                         /* We don't know for sure what's up with tlbiel, so
 336                          * for now we only set it for 4K and 64K pages
 337                          */
 338                         if (idx == MMU_PAGE_4K || idx == MMU_PAGE_64K)
 339                                 def->tlbiel = 1;
 340                         else
 341                                 def->tlbiel = 0;
 342
 343                         DBG(" %d: shift=%02x, sllp=%04lx, avpnm=%08lx, "
 344                             "tlbiel=%d, penc=%d\n",
 345                             idx, shift, def->sllp, def->avpnm, def->tlbiel,
 346                             def->penc);
 347                 }
 348                 return 1;
 349         }
 350         return 0;
 351 }
 352
 353 #ifdef CONFIG_HUGETLB_PAGE
 354 /* Scan for 16G memory blocks that have been set aside for huge pages
 355  * and reserve those blocks for 16G huge pages.
 356  */
 357 static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
 358                                         const char *uname, int depth,
 359                                         void *data) {
 360         char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 361         unsigned long *addr_prop;
 362         u32 *page_count_prop;
 363         unsigned int expected_pages;
 364         long unsigned int phys_addr;
 365         long unsigned int block_size;
 366
 367         /* We are scanning "memory" nodes only */
 368         if (type == NULL || strcmp(type, "memory") != 0)
 369                 return 0;
 370
 371         /* This property is the log base 2 of the number of virtual pages that
 372          * will represent this memory block. */
 373         page_count_prop = of_get_flat_dt_prop(node, "ibm,expected#pages", NULL);
 374         if (page_count_prop == NULL)
 375                 return 0;
 376         expected_pages = (1 << page_count_prop[0]);
 377         addr_prop = of_get_flat_dt_prop(node, "reg", NULL);
 378         if (addr_prop == NULL)
 379                 return 0;
 380         phys_addr = addr_prop[0];
 381         block_size = addr_prop[1];
 382         if (block_size != (16 * GB))
 383                 return 0;
 384         printk(KERN_INFO "Huge page(16GB) memory: "
 385                         "addr = 0x%lX size = 0x%lX pages = %d\n",
 386                         phys_addr, block_size, expected_pages);
 387         if (phys_addr + (16 * GB) <= memblock_end_of_DRAM()) {
 388                 memblock_reserve(phys_addr, block_size * expected_pages);
 389                 add_gpage(phys_addr, block_size, expected_pages);
 390         }
 391         return 0;
 392 }
 393 #endif /* CONFIG_HUGETLB_PAGE */
 394
 395 static void __init htab_init_page_sizes(void)
 396 {
 397         int rc;
 398
 399         /* Default to 4K pages only */
 400         memcpy(mmu_psize_defs, mmu_psize_defaults_old,
 401                sizeof(mmu_psize_defaults_old));
 402
 403         /*
 404          * Try to find the available page sizes in the device-tree
 405          */
 406         rc = of_scan_flat_dt(htab_dt_scan_page_sizes, NULL);
 407         if (rc != 0)  /* Found */
 408                 goto found;
 409
 410         /*
 411          * Not in the device-tree, let's fallback on known size
 412          * list for 16M capable GP & GR
 413          */
 414         if (mmu_has_feature(MMU_FTR_16M_PAGE))
 415                 memcpy(mmu_psize_defs, mmu_psize_defaults_gp,
 416                        sizeof(mmu_psize_defaults_gp));
 417  found:
 418 #ifndef CONFIG_DEBUG_PAGEALLOC
 419         /*
 420          * Pick a size for the linear mapping. Currently, we only support
 421          * 16M, 1M and 4K which is the default
 422          */
 423         if (mmu_psize_defs[MMU_PAGE_16M].shift)
 424                 mmu_linear_psize = MMU_PAGE_16M;
 425         else if (mmu_psize_defs[MMU_PAGE_1M].shift)
 426                 mmu_linear_psize = MMU_PAGE_1M;
 427 #endif /* CONFIG_DEBUG_PAGEALLOC */
 428
 429 #ifdef CONFIG_PPC_64K_PAGES
 430         /*
 431          * Pick a size for the ordinary pages. Default is 4K, we support
 432          * 64K for user mappings and vmalloc if supported by the processor.
 433          * We only use 64k for ioremap if the processor
 434          * (and firmware) support cache-inhibited large pages.
 435          * If not, we use 4k and set mmu_ci_restrictions so that
 436          * hash_page knows to switch processes that use cache-inhibited
 437          * mappings to 4k pages.
 438          */
 439         if (mmu_psize_defs[MMU_PAGE_64K].shift) {
 440                 mmu_virtual_psize = MMU_PAGE_64K;
 441                 mmu_vmalloc_psize = MMU_PAGE_64K;
 442                 if (mmu_linear_psize == MMU_PAGE_4K)
 443                         mmu_linear_psize = MMU_PAGE_64K;
 444                 if (mmu_has_feature(MMU_FTR_CI_LARGE_PAGE)) {
 445                         /*
 446                          * Don't use 64k pages for ioremap on pSeries, since
 447                          * that would stop us accessing the HEA ethernet.
 448                          */
 449                         if (!machine_is(pseries))
 450                                 mmu_io_psize = MMU_PAGE_64K;
 451                 } else
 452                         mmu_ci_restrictions = 1;
 453         }
 454 #endif /* CONFIG_PPC_64K_PAGES */
 455
 456 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 457         /* We try to use 16M pages for vmemmap if that is supported
 458          * and we have at least 1G of RAM at boot
 459          */
 460         if (mmu_psize_defs[MMU_PAGE_16M].shift &&
 461             memblock_phys_mem_size() >= 0x40000000)
 462                 mmu_vmemmap_psize = MMU_PAGE_16M;
 463         else if (mmu_psize_defs[MMU_PAGE_64K].shift)
 464                 mmu_vmemmap_psize = MMU_PAGE_64K;
 465         else
 466                 mmu_vmemmap_psize = MMU_PAGE_4K;
 467 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 468
 469         printk(KERN_DEBUG "Page orders: linear mapping = %d, "
 470                "virtual = %d, io = %d"
 471 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 472                ", vmemmap = %d"
 473 #endif
 474                "\n",
 475                mmu_psize_defs[mmu_linear_psize].shift,
 476                mmu_psize_defs[mmu_virtual_psize].shift,
 477                mmu_psize_defs[mmu_io_psize].shift
 478 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 479                ,mmu_psize_defs[mmu_vmemmap_psize].shift
 480 #endif
 481                );
 482
 483 #ifdef CONFIG_HUGETLB_PAGE
 484         /* Reserve 16G huge page memory sections for huge pages */
 485         of_scan_flat_dt(htab_dt_scan_hugepage_blocks, NULL);
 486 #endif /* CONFIG_HUGETLB_PAGE */
 487 }
 488
 489 static int __init htab_dt_scan_pftsize(unsigned long node,
 490                                        const char *uname, int depth,
 491                                        void *data)
 492 {
 493         char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 494         u32 *prop;
 495
 496         /* We are scanning "cpu" nodes only */
 497         if (type == NULL || strcmp(type, "cpu") != 0)
 498                 return 0;
 499
 500         prop = (u32 *)of_get_flat_dt_prop(node, "ibm,pft-size", NULL);
 501         if (prop != NULL) {
 502                 /* pft_size[0] is the NUMA CEC cookie */
 503                 ppc64_pft_size = prop[1];
 504                 return 1;
 505         }
 506         return 0;
 507 }
 508
 509 static unsigned long __init htab_get_table_size(void)
 510 {
 511         unsigned long mem_size, rnd_mem_size, pteg_count, psize;
 512
 513         /* If hash size isn't already provided by the platform, we try to
 514          * retrieve it from the device-tree. If it's not there neither, we
 515          * calculate it now based on the total RAM size
 516          */
 517         if (ppc64_pft_size == 0)
 518                 of_scan_flat_dt(htab_dt_scan_pftsize, NULL);
 519         if (ppc64_pft_size)
 520                 return 1UL << ppc64_pft_size;
 521
 522         /* round mem_size up to next power of 2 */
 523         mem_size = memblock_phys_mem_size();
 524         rnd_mem_size = 1UL << __ilog2(mem_size);
 525         if (rnd_mem_size < mem_size)
 526                 rnd_mem_size <<= 1;
 527
 528         /* # pages / 2 */
 529         psize = mmu_psize_defs[mmu_virtual_psize].shift;
 530         pteg_count = max(rnd_mem_size >> (psize + 1), 1UL << 11);
 531
 532         return pteg_count << 7;
 533 }
 534
 535 #ifdef CONFIG_MEMORY_HOTPLUG
 536 int create_section_mapping(unsigned long start, unsigned long end)
 537 {
 538         return htab_bolt_mapping(start, end, __pa(start),
 539                                  pgprot_val(PAGE_KERNEL), mmu_linear_psize,
 540                                  mmu_kernel_ssize);
 541 }
 542
 543 int remove_section_mapping(unsigned long start, unsigned long end)
 544 {
 545         return htab_remove_mapping(start, end, mmu_linear_psize,
 546                         mmu_kernel_ssize);
 547 }
 548 #endif /* CONFIG_MEMORY_HOTPLUG */
 549
 550 #define FUNCTION_TEXT(A)        ((*(unsigned long *)(A)))
 551
 552 static void __init htab_finish_init(void)
 553 {
 554         extern unsigned int *htab_call_hpte_insert1;
 555         extern unsigned int *htab_call_hpte_insert2;
 556         extern unsigned int *htab_call_hpte_remove;
 557         extern unsigned int *htab_call_hpte_updatepp;
 558
 559 #ifdef CONFIG_PPC_HAS_HASH_64K
 560         extern unsigned int *ht64_call_hpte_insert1;
 561         extern unsigned int *ht64_call_hpte_insert2;
 562         extern unsigned int *ht64_call_hpte_remove;
 563         extern unsigned int *ht64_call_hpte_updatepp;
 564
 565         patch_branch(ht64_call_hpte_insert1,
 566                 FUNCTION_TEXT(ppc_md.hpte_insert),
 567                 BRANCH_SET_LINK);
 568         patch_branch(ht64_call_hpte_insert2,
 569                 FUNCTION_TEXT(ppc_md.hpte_insert),
 570                 BRANCH_SET_LINK);
 571         patch_branch(ht64_call_hpte_remove,
 572                 FUNCTION_TEXT(ppc_md.hpte_remove),
 573                 BRANCH_SET_LINK);
 574         patch_branch(ht64_call_hpte_updatepp,
 575                 FUNCTION_TEXT(ppc_md.hpte_updatepp),
 576                 BRANCH_SET_LINK);
 577
 578 #endif /* CONFIG_PPC_HAS_HASH_64K */
 579
 580         patch_branch(htab_call_hpte_insert1,
 581                 FUNCTION_TEXT(ppc_md.hpte_insert),
 582                 BRANCH_SET_LINK);
 583         patch_branch(htab_call_hpte_insert2,
 584                 FUNCTION_TEXT(ppc_md.hpte_insert),
 585                 BRANCH_SET_LINK);
 586         patch_branch(htab_call_hpte_remove,
 587                 FUNCTION_TEXT(ppc_md.hpte_remove),
 588                 BRANCH_SET_LINK);
 589         patch_branch(htab_call_hpte_updatepp,
 590                 FUNCTION_TEXT(ppc_md.hpte_updatepp),
 591                 BRANCH_SET_LINK);
 592 }
 593
 594 static void __init htab_initialize(void)
 595 {
 596         unsigned long table;
 597         unsigned long pteg_count;
 598         unsigned long prot;
 599         unsigned long base = 0, size = 0, limit;
 600         struct memblock_region *reg;
 601
 602         DBG(" -> htab_initialize()\n");
 603
 604         /* Initialize segment sizes */
 605         htab_init_seg_sizes();
 606
 607         /* Initialize page sizes */
 608         htab_init_page_sizes();
 609
 610         if (mmu_has_feature(MMU_FTR_1T_SEGMENT)) {
 611                 mmu_kernel_ssize = MMU_SEGSIZE_1T;
 612                 mmu_highuser_ssize = MMU_SEGSIZE_1T;
 613                 printk(KERN_INFO "Using 1TB segments\n");
 614         }
 615
 616         /*
 617          * Calculate the required size of the htab.  We want the number of
 618          * PTEGs to equal one half the number of real pages.
 619          */
 620         htab_size_bytes = htab_get_table_size();
 621         pteg_count = htab_size_bytes >> 7;
 622
 623         htab_hash_mask = pteg_count - 1;
 624
 625         if (firmware_has_feature(FW_FEATURE_LPAR)) {
 626                 /* Using a hypervisor which owns the htab */
 627                 htab_address = NULL;
 628                 _SDR1 = 0;
 629 #ifdef CONFIG_FA_DUMP
 630                 /*
 631                  * If firmware assisted dump is active firmware preserves
 632                  * the contents of htab along with entire partition memory.
 633                  * Clear the htab if firmware assisted dump is active so
 634                  * that we dont end up using old mappings.
 635                  */
 636                 if (is_fadump_active() && ppc_md.hpte_clear_all)
 637                         ppc_md.hpte_clear_all();
 638 #endif
 639         } else {
 640                 /* Find storage for the HPT.  Must be contiguous in
 641                  * the absolute address space. On cell we want it to be
 642                  * in the first 2 Gig so we can use it for IOMMU hacks.
 643                  */
 644                 if (machine_is(cell))
 645                         limit = 0x80000000;
 646                 else
 647                         limit = MEMBLOCK_ALLOC_ANYWHERE;
 648
 649                 table = memblock_alloc_base(htab_size_bytes, htab_size_bytes, limit);
 650
 651                 DBG("Hash table allocated at %lx, size: %lx\n", table,
 652                     htab_size_bytes);
 653
 654                 htab_address = abs_to_virt(table);
 655
 656                 /* htab absolute addr + encoded htabsize */
 657                 _SDR1 = table + __ilog2(pteg_count) - 11;
 658
 659                 /* Initialize the HPT with no entries */
 660                 memset((void *)table, 0, htab_size_bytes);
 661
 662                 /* Set SDR1 */
 663                 mtspr(SPRN_SDR1, _SDR1);
 664         }
 665
 666         prot = pgprot_val(PAGE_KERNEL);
 667
 668 #ifdef CONFIG_DEBUG_PAGEALLOC
 669         linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
 670         linear_map_hash_slots = __va(memblock_alloc_base(linear_map_hash_count,
 671                                                     1, ppc64_rma_size));
 672         memset(linear_map_hash_slots, 0, linear_map_hash_count);
 673 #endif /* CONFIG_DEBUG_PAGEALLOC */
 674
 675         /* On U3 based machines, we need to reserve the DART area and
 676          * _NOT_ map it to avoid cache paradoxes as it's remapped non
 677          * cacheable later on
 678          */
 679
 680         /* create bolted the linear mapping in the hash table */
 681         for_each_memblock(memory, reg) {
 682                 base = (unsigned long)__va(reg->base);
 683                 size = reg->size;
 684
 685                 DBG("creating mapping for region: %lx..%lx (prot: %lx)\n",
 686                     base, size, prot);
 687
 688 #ifdef CONFIG_U3_DART
 689                 /* Do not map the DART space. Fortunately, it will be aligned
 690                  * in such a way that it will not cross two memblock regions and
 691                  * will fit within a single 16Mb page.
 692                  * The DART space is assumed to be a full 16Mb region even if
 693                  * we only use 2Mb of that space. We will use more of it later
 694                  * for AGP GART. We have to use a full 16Mb large page.
 695                  */
 696                 DBG("DART base: %lx\n", dart_tablebase);
 697
 698                 if (dart_tablebase != 0 && dart_tablebase >= base
 699                     && dart_tablebase < (base + size)) {
 700                         unsigned long dart_table_end = dart_tablebase + 16 * MB;
 701                         if (base != dart_tablebase)
 702                                 BUG_ON(htab_bolt_mapping(base, dart_tablebase,
 703                                                         __pa(base), prot,
 704                                                         mmu_linear_psize,
 705                                                         mmu_kernel_ssize));
 706                         if ((base + size) > dart_table_end)
 707                                 BUG_ON(htab_bolt_mapping(dart_tablebase+16*MB,
 708                                                         base + size,
 709                                                         __pa(dart_table_end),
 710                                                          prot,
 711                                                          mmu_linear_psize,
 712                                                          mmu_kernel_ssize));
 713                         continue;
 714                 }
 715 #endif /* CONFIG_U3_DART */
 716                 BUG_ON(htab_bolt_mapping(base, base + size, __pa(base),
 717                                 prot, mmu_linear_psize, mmu_kernel_ssize));
 718         }
 719         memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
 720
 721         /*
 722          * If we have a memory_limit and we've allocated TCEs then we need to
 723          * explicitly map the TCE area at the top of RAM. We also cope with the
 724          * case that the TCEs start below memory_limit.
 725          * tce_alloc_start/end are 16MB aligned so the mapping should work
 726          * for either 4K or 16MB pages.
 727          */
 728         if (tce_alloc_start) {
 729                 tce_alloc_start = (unsigned long)__va(tce_alloc_start);
 730                 tce_alloc_end = (unsigned long)__va(tce_alloc_end);
 731
 732                 if (base + size >= tce_alloc_start)
 733                         tce_alloc_start = base + size + 1;
 734
 735                 BUG_ON(htab_bolt_mapping(tce_alloc_start, tce_alloc_end,
 736                                          __pa(tce_alloc_start), prot,
 737                                          mmu_linear_psize, mmu_kernel_ssize));
 738         }
 739
 740         htab_finish_init();
 741
 742         DBG(" <- htab_initialize()\n");
 743 }
 744 #undef KB
 745 #undef MB
 746
 747 void __init early_init_mmu(void)
 748 {
 749         /* Setup initial STAB address in the PACA */
 750         get_paca()->stab_real = __pa((u64)&initial_stab);
 751         get_paca()->stab_addr = (u64)&initial_stab;
 752
 753         /* Initialize the MMU Hash table and create the linear mapping
 754          * of memory. Has to be done before stab/slb initialization as
 755          * this is currently where the page size encoding is obtained
 756          */
 757         htab_initialize();
 758
 759         /* Initialize stab / SLB management */
 760         if (mmu_has_feature(MMU_FTR_SLB))
 761                 slb_initialize();
 762 }
 763
 764 #ifdef CONFIG_SMP
 765 void __cpuinit early_init_mmu_secondary(void)
 766 {
 767         /* Initialize hash table for that CPU */
 768         if (!firmware_has_feature(FW_FEATURE_LPAR))
 769                 mtspr(SPRN_SDR1, _SDR1);
 770
 771         /* Initialize STAB/SLB. We use a virtual address as it works
 772          * in real mode on pSeries.
 773          */
 774         if (mmu_has_feature(MMU_FTR_SLB))
 775                 slb_initialize();
 776         else
 777                 stab_initialize(get_paca()->stab_addr);
 778 }
 779 #endif /* CONFIG_SMP */
 780
 781 /*
 782  * Called by asm hashtable.S for doing lazy icache flush
 783  */
 784 unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
 785 {
 786         struct page *page;
 787
 788         if (!pfn_valid(pte_pfn(pte)))
 789                 return pp;
 790
 791         page = pte_page(pte);
 792
 793         /* page is dirty */
 794         if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
 795                 if (trap == 0x400) {
 796                         flush_dcache_icache_page(page);
 797                         set_bit(PG_arch_1, &page->flags);
 798                 } else
 799                         pp |= HPTE_R_N;
 800         }
 801         return pp;
 802 }
 803
 804 #ifdef CONFIG_PPC_MM_SLICES
 805 unsigned int get_paca_psize(unsigned long addr)
 806 {
 807         unsigned long index, slices;
 808
 809         if (addr < SLICE_LOW_TOP) {
 810                 slices = get_paca()->context.low_slices_psize;
 811                 index = GET_LOW_SLICE_INDEX(addr);
 812         } else {
 813                 slices = get_paca()->context.high_slices_psize;
 814                 index = GET_HIGH_SLICE_INDEX(addr);
 815         }
 816         return (slices >> (index * 4)) & 0xF;
 817 }
 818
 819 #else
 820 unsigned int get_paca_psize(unsigned long addr)
 821 {
 822         return get_paca()->context.user_psize;
 823 }
 824 #endif
 825
 826 /*
 827  * Demote a segment to using 4k pages.
 828  * For now this makes the whole process use 4k pages.
 829  */
 830 #ifdef CONFIG_PPC_64K_PAGES
 831 void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
 832 {
 833         if (get_slice_psize(mm, addr) == MMU_PAGE_4K)
 834                 return;
 835         slice_set_range_psize(mm, addr, 1, MMU_PAGE_4K);
 836 #ifdef CONFIG_SPU_BASE
 837         spu_flush_all_slbs(mm);
 838 #endif
 839         if (get_paca_psize(addr) != MMU_PAGE_4K) {
 840                 get_paca()->context = mm->context;
 841                 slb_flush_and_rebolt();
 842         }
 843 }
 844 #endif /* CONFIG_PPC_64K_PAGES */
 845
 846 #ifdef CONFIG_PPC_SUBPAGE_PROT
 847 /*
 848  * This looks up a 2-bit protection code for a 4k subpage of a 64k page.
 849  * Userspace sets the subpage permissions using the subpage_prot system call.
 850  *
 851  * Result is 0: full permissions, _PAGE_RW: read-only,
 852  * _PAGE_USER or _PAGE_USER|_PAGE_RW: no access.
 853  */
 854 static int subpage_protection(struct mm_struct *mm, unsigned long ea)
 855 {
 856         struct subpage_prot_table *spt = &mm->context.spt;
 857         u32 spp = 0;
 858         u32 **sbpm, *sbpp;
 859
 860         if (ea >= spt->maxaddr)
 861                 return 0;
 862         if (ea < 0x100000000) {
 863                 /* addresses below 4GB use spt->low_prot */
 864                 sbpm = spt->low_prot;
 865         } else {
 866                 sbpm = spt->protptrs[ea >> SBP_L3_SHIFT];
 867                 if (!sbpm)
 868                         return 0;
 869         }
 870         sbpp = sbpm[(ea >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1)];
 871         if (!sbpp)
 872                 return 0;
 873         spp = sbpp[(ea >> PAGE_SHIFT) & (SBP_L1_COUNT - 1)];
 874
 875         /* extract 2-bit bitfield for this 4k subpage */
 876         spp >>= 30 - 2 * ((ea >> 12) & 0xf);
 877
 878         /* turn 0,1,2,3 into combination of _PAGE_USER and _PAGE_RW */
 879         spp = ((spp & 2) ? _PAGE_USER : 0) | ((spp & 1) ? _PAGE_RW : 0);
 880         return spp;
 881 }
 882
 883 #else /* CONFIG_PPC_SUBPAGE_PROT */
 884 static inline int subpage_protection(struct mm_struct *mm, unsigned long ea)
 885 {
 886         return 0;
 887 }
 888 #endif
 889
 890 void hash_failure_debug(unsigned long ea, unsigned long access,
 891                         unsigned long vsid, unsigned long trap,
 892                         int ssize, int psize, unsigned long pte)
 893 {
 894         if (!printk_ratelimit())
 895                 return;
 896         pr_info("mm: Hashing failure ! EA=0x%lx access=0x%lx current=%s\n",
 897                 ea, access, current->comm);
 898         pr_info("    trap=0x%lx vsid=0x%lx ssize=%d psize=%d pte=0x%lx\n",
 899                 trap, vsid, ssize, psize, pte);
 900 }
 901
 902 /* Result code is:
 903  *  0 - handled
 904  *  1 - normal page fault
 905  * -1 - critical hash insertion error
 906  * -2 - access not permitted by subpage protection mechanism
 907  */
 908 int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
 909 {
 910         pgd_t *pgdir;
 911         unsigned long vsid;
 912         struct mm_struct *mm;
 913         pte_t *ptep;
 914         unsigned hugeshift;
 915         const struct cpumask *tmp;
 916         int rc, user_region = 0, local = 0;
 917         int psize, ssize;
 918
 919         DBG_LOW("hash_page(ea=%016lx, access=%lx, trap=%lx\n",
 920                 ea, access, trap);
 921
 922         if ((ea & ~REGION_MASK) >= PGTABLE_RANGE) {
 923                 DBG_LOW(" out of pgtable range !\n");
 924                 return 1;
 925         }
 926
 927         /* Get region & vsid */
 928         switch (REGION_ID(ea)) {
 929         case USER_REGION_ID:
 930                 user_region = 1;
 931                 mm = current->mm;
 932                 if (! mm) {
 933                         DBG_LOW(" user region with no mm !\n");
 934                         return 1;
 935                 }
 936                 psize = get_slice_psize(mm, ea);
 937                 ssize = user_segment_size(ea);
 938                 vsid = get_vsid(mm->context.id, ea, ssize);
 939                 break;
 940         case VMALLOC_REGION_ID:
 941                 mm = &init_mm;
 942                 vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
 943                 if (ea < VMALLOC_END)
 944                         psize = mmu_vmalloc_psize;
 945                 else
 946                         psize = mmu_io_psize;
 947                 ssize = mmu_kernel_ssize;
 948                 break;
 949         default:
 950                 /* Not a valid range
 951                  * Send the problem up to do_page_fault
 952                  */
 953                 return 1;
 954         }
 955         DBG_LOW(" mm=%p, mm->pgdir=%p, vsid=%016lx\n", mm, mm->pgd, vsid);
 956
 957         /* Get pgdir */
 958         pgdir = mm->pgd;
 959         if (pgdir == NULL)
 960                 return 1;
 961
 962         /* Check CPU locality */
 963         tmp = cpumask_of(smp_processor_id());
 964         if (user_region && cpumask_equal(mm_cpumask(mm), tmp))
 965                 local = 1;
 966
 967 #ifndef CONFIG_PPC_64K_PAGES
 968         /* If we use 4K pages and our psize is not 4K, then we might
 969          * be hitting a special driver mapping, and need to align the
 970          * address before we fetch the PTE.
 971          *
 972          * It could also be a hugepage mapping, in which case this is
 973          * not necessary, but it's not harmful, either.
 974          */
 975         if (psize != MMU_PAGE_4K)
 976                 ea &= ~((1ul << mmu_psize_defs[psize].shift) - 1);
 977 #endif /* CONFIG_PPC_64K_PAGES */
 978
 979         /* Get PTE and page size from page tables */
 980         ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
 981         if (ptep == NULL || !pte_present(*ptep)) {
 982                 DBG_LOW(" no PTE !\n");
 983                 return 1;
 984         }
 985
 986         /* Add _PAGE_PRESENT to the required access perm */
 987         access |= _PAGE_PRESENT;
 988
 989         /* Pre-check access permissions (will be re-checked atomically
 990          * in __hash_page_XX but this pre-check is a fast path
 991          */
 992         if (access & ~pte_val(*ptep)) {
 993                 DBG_LOW(" no access !\n");
 994                 return 1;
 995         }
 996
 997 #ifdef CONFIG_HUGETLB_PAGE
 998         if (hugeshift)
 999                 return __hash_page_huge(ea, access, vsid, ptep, trap, local,
1000                                         ssize, hugeshift, psize);
1001 #endif /* CONFIG_HUGETLB_PAGE */
1002
1003 #ifndef CONFIG_PPC_64K_PAGES
1004         DBG_LOW(" i-pte: %016lx\n", pte_val(*ptep));
1005 #else
1006         DBG_LOW(" i-pte: %016lx %016lx\n", pte_val(*ptep),
1007                 pte_val(*(ptep + PTRS_PER_PTE)));
1008 #endif
1009         /* Do actual hashing */
1010 #ifdef CONFIG_PPC_64K_PAGES
1011         /* If _PAGE_4K_PFN is set, make sure this is a 4k segment */
1012         if ((pte_val(*ptep) & _PAGE_4K_PFN) && psize == MMU_PAGE_64K) {
1013                 demote_segment_4k(mm, ea);
1014                 psize = MMU_PAGE_4K;
1015         }
1016
1017         /* If this PTE is non-cacheable and we have restrictions on
1018          * using non cacheable large pages, then we switch to 4k
1019          */
1020         if (mmu_ci_restrictions && psize == MMU_PAGE_64K &&
1021             (pte_val(*ptep) & _PAGE_NO_CACHE)) {
1022                 if (user_region) {
1023                         demote_segment_4k(mm, ea);
1024                         psize = MMU_PAGE_4K;
1025                 } else if (ea < VMALLOC_END) {
1026                         /*
1027                          * some driver did a non-cacheable mapping
1028                          * in vmalloc space, so switch vmalloc
1029                          * to 4k pages
1030                          */
1031                         printk(KERN_ALERT "Reducing vmalloc segment "
1032                                "to 4kB pages because of "
1033                                "non-cacheable mapping\n");
1034                         psize = mmu_vmalloc_psize = MMU_PAGE_4K;
1035 #ifdef CONFIG_SPU_BASE
1036                         spu_flush_all_slbs(mm);
1037 #endif
1038                 }
1039         }
1040         if (user_region) {
1041                 if (psize != get_paca_psize(ea)) {
1042                         get_paca()->context = mm->context;
1043                         slb_flush_and_rebolt();
1044                 }
1045         } else if (get_paca()->vmalloc_sllp !=
1046                    mmu_psize_defs[mmu_vmalloc_psize].sllp) {
1047                 get_paca()->vmalloc_sllp =
1048                         mmu_psize_defs[mmu_vmalloc_psize].sllp;
1049                 slb_vmalloc_update();
1050         }
1051 #endif /* CONFIG_PPC_64K_PAGES */
1052
1053 #ifdef CONFIG_PPC_HAS_HASH_64K
1054         if (psize == MMU_PAGE_64K)
1055                 rc = __hash_page_64K(ea, access, vsid, ptep, trap, local, ssize);
1056         else
1057 #endif /* CONFIG_PPC_HAS_HASH_64K */
1058         {
1059                 int spp = subpage_protection(mm, ea);
1060                 if (access & spp)
1061                         rc = -2;
1062                 else
1063                         rc = __hash_page_4K(ea, access, vsid, ptep, trap,
1064                                             local, ssize, spp);
1065         }
1066
1067         /* Dump some info in case of hash insertion failure, they should
1068          * never happen so it is really useful to know if/when they do
1069          */
1070         if (rc == -1)
1071                 hash_failure_debug(ea, access, vsid, trap, ssize, psize,
1072                                    pte_val(*ptep));
1073 #ifndef CONFIG_PPC_64K_PAGES
1074         DBG_LOW(" o-pte: %016lx\n", pte_val(*ptep));
1075 #else
1076         DBG_LOW(" o-pte: %016lx %016lx\n", pte_val(*ptep),
1077                 pte_val(*(ptep + PTRS_PER_PTE)));
1078 #endif
1079         DBG_LOW(" -> rc=%d\n", rc);
1080         return rc;
1081 }
1082 EXPORT_SYMBOL_GPL(hash_page);
1083
1084 void hash_preload(struct mm_struct *mm, unsigned long ea,
1085                   unsigned long access, unsigned long trap)
1086 {
1087         unsigned long vsid;
1088         pgd_t *pgdir;
1089         pte_t *ptep;
1090         unsigned long flags;
1091         int rc, ssize, local = 0;
1092
1093         BUG_ON(REGION_ID(ea) != USER_REGION_ID);
1094
1095 #ifdef CONFIG_PPC_MM_SLICES
1096         /* We only prefault standard pages for now */
1097         if (unlikely(get_slice_psize(mm, ea) != mm->context.user_psize))
1098                 return;
1099 #endif
1100
1101         DBG_LOW("hash_preload(mm=%p, mm->pgdir=%p, ea=%016lx, access=%lx,"
1102                 " trap=%lx\n", mm, mm->pgd, ea, access, trap);
1103
1104         /* Get Linux PTE if available */
1105         pgdir = mm->pgd;
1106         if (pgdir == NULL)
1107                 return;
1108         ptep = find_linux_pte(pgdir, ea);
1109         if (!ptep)
1110                 return;
1111
1112 #ifdef CONFIG_PPC_64K_PAGES
1113         /* If either _PAGE_4K_PFN or _PAGE_NO_CACHE is set (and we are on
1114          * a 64K kernel), then we don't preload, hash_page() will take
1115          * care of it once we actually try to access the page.
1116          * That way we don't have to duplicate all of the logic for segment
1117          * page size demotion here
1118          */
1119         if (pte_val(*ptep) & (_PAGE_4K_PFN | _PAGE_NO_CACHE))
1120                 return;
1121 #endif /* CONFIG_PPC_64K_PAGES */
1122
1123         /* Get VSID */
1124         ssize = user_segment_size(ea);
1125         vsid = get_vsid(mm->context.id, ea, ssize);
1126
1127         /* Hash doesn't like irqs */
1128         local_irq_save(flags);
1129
1130         /* Is that local to this CPU ? */
1131         if (cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
1132                 local = 1;
1133
1134         /* Hash it in */
1135 #ifdef CONFIG_PPC_HAS_HASH_64K
1136         if (mm->context.user_psize == MMU_PAGE_64K)
1137                 rc = __hash_page_64K(ea, access, vsid, ptep, trap, local, ssize);
1138         else
1139 #endif /* CONFIG_PPC_HAS_HASH_64K */
1140                 rc = __hash_page_4K(ea, access, vsid, ptep, trap, local, ssize,
1141                                     subpage_protection(mm, ea));
1142
1143         /* Dump some info in case of hash insertion failure, they should
1144          * never happen so it is really useful to know if/when they do
1145          */
1146         if (rc == -1)
1147                 hash_failure_debug(ea, access, vsid, trap, ssize,
1148                                    mm->context.user_psize, pte_val(*ptep));
1149
1150         local_irq_restore(flags);
1151 }
1152
1153 /* WARNING: This is called from hash_low_64.S, if you change this prototype,
1154  *          do not forget to update the assembly call site !
1155  */
1156 void flush_hash_page(unsigned long va, real_pte_t pte, int psize, int ssize,
1157                      int local)
1158 {
1159         unsigned long hash, index, shift, hidx, slot;
1160
1161         DBG_LOW("flush_hash_page(va=%016lx)\n", va);
1162         pte_iterate_hashed_subpages(pte, psize, va, index, shift) {
1163                 hash = hpt_hash(va, shift, ssize);
1164                 hidx = __rpte_to_hidx(pte, index);
1165                 if (hidx & _PTEIDX_SECONDARY)
1166                         hash = ~hash;
1167                 slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
1168                 slot += hidx & _PTEIDX_GROUP_IX;
1169                 DBG_LOW(" sub %ld: hash=%lx, hidx=%lx\n", index, slot, hidx);
1170                 ppc_md.hpte_invalidate(slot, va, psize, ssize, local);
1171         } pte_iterate_hashed_end();
1172 }
1173
1174 void flush_hash_range(unsigned long number, int local)
1175 {
1176         if (ppc_md.flush_hash_range)
1177                 ppc_md.flush_hash_range(number, local);
1178         else {
1179                 int i;
1180                 struct ppc64_tlb_batch *batch =
1181                         &__get_cpu_var(ppc64_tlb_batch);
1182
1183                 for (i = 0; i < number; i++)
1184                         flush_hash_page(batch->vaddr[i], batch->pte[i],
1185                                         batch->psize, batch->ssize, local);
1186         }
1187 }
1188
1189 /*
1190  * low_hash_fault is called when we the low level hash code failed
1191  * to instert a PTE due to an hypervisor error
1192  */
1193 void low_hash_fault(struct pt_regs *regs, unsigned long address, int rc)
1194 {
1195         if (user_mode(regs)) {
1196 #ifdef CONFIG_PPC_SUBPAGE_PROT
1197                 if (rc == -2)
1198                         _exception(SIGSEGV, regs, SEGV_ACCERR, address);
1199                 else
1200 #endif
1201                         _exception(SIGBUS, regs, BUS_ADRERR, address);
1202         } else
1203                 bad_page_fault(regs, address, SIGBUS);
1204 }
1205
1206 #ifdef CONFIG_DEBUG_PAGEALLOC
1207 static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
1208 {
1209         unsigned long hash, hpteg;
1210         unsigned long vsid = get_kernel_vsid(vaddr, mmu_kernel_ssize);
1211         unsigned long va = hpt_va(vaddr, vsid, mmu_kernel_ssize);
1212         unsigned long mode = htab_convert_pte_flags(PAGE_KERNEL);
1213         int ret;
1214
1215         hash = hpt_hash(va, PAGE_SHIFT, mmu_kernel_ssize);
1216         hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
1217
1218         ret = ppc_md.hpte_insert(hpteg, va, __pa(vaddr),
1219                                  mode, HPTE_V_BOLTED,
1220                                  mmu_linear_psize, mmu_kernel_ssize);
1221         BUG_ON (ret < 0);
1222         spin_lock(&linear_map_hash_lock);
1223         BUG_ON(linear_map_hash_slots[lmi] & 0x80);
1224         linear_map_hash_slots[lmi] = ret | 0x80;
1225         spin_unlock(&linear_map_hash_lock);
1226 }
1227
1228 static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long lmi)
1229 {
1230         unsigned long hash, hidx, slot;
1231         unsigned long vsid = get_kernel_vsid(vaddr, mmu_kernel_ssize);
1232         unsigned long va = hpt_va(vaddr, vsid, mmu_kernel_ssize);
1233
1234         hash = hpt_hash(va, PAGE_SHIFT, mmu_kernel_ssize);
1235         spin_lock(&linear_map_hash_lock);
1236         BUG_ON(!(linear_map_hash_slots[lmi] & 0x80));
1237         hidx = linear_map_hash_slots[lmi] & 0x7f;
1238         linear_map_hash_slots[lmi] = 0;
1239         spin_unlock(&linear_map_hash_lock);
1240         if (hidx & _PTEIDX_SECONDARY)
1241                 hash = ~hash;
1242         slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
1243         slot += hidx & _PTEIDX_GROUP_IX;
1244         ppc_md.hpte_invalidate(slot, va, mmu_linear_psize, mmu_kernel_ssize, 0);
1245 }
1246
1247 void kernel_map_pages(struct page *page, int numpages, int enable)
1248 {
1249         unsigned long flags, vaddr, lmi;
1250         int i;
1251
1252         local_irq_save(flags);
1253         for (i = 0; i < numpages; i++, page++) {
1254                 vaddr = (unsigned long)page_address(page);
1255                 lmi = __pa(vaddr) >> PAGE_SHIFT;
1256                 if (lmi >= linear_map_hash_count)
1257                         continue;
1258                 if (enable)
1259                         kernel_map_linear_page(vaddr, lmi);
1260                 else
1261                         kernel_unmap_linear_page(vaddr, lmi);
1262         }
1263         local_irq_restore(flags);
1264 }
1265 #endif /* CONFIG_DEBUG_PAGEALLOC */
1266
1267 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
1268                                 phys_addr_t first_memblock_size)
1269 {
1270         /* We don't currently support the first MEMBLOCK not mapping 0
1271          * physical on those processors
1272          */
1273         BUG_ON(first_memblock_base != 0);
1274
1275         /* On LPAR systems, the first entry is our RMA region,
1276          * non-LPAR 64-bit hash MMU systems don't have a limitation
1277          * on real mode access, but using the first entry works well
1278          * enough. We also clamp it to 1G to avoid some funky things
1279          * such as RTAS bugs etc...
1280          */
1281         ppc64_rma_size = min_t(u64, first_memblock_size, 0x40000000);
1282
1283         /* Finally limit subsequent allocations */
1284         memblock_set_current_limit(ppc64_rma_size);
1285 }