arch/powerpc/mm/hash_native_64.c

   1 /*
   2  * native hashtable management.
   3  *
   4  * SMP scalability work:
   5  *    Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 #undef DEBUG_LOW
  14
  15 #include <linux/spinlock.h>
  16 #include <linux/bitops.h>
  17 #include <linux/threads.h>
  18 #include <linux/smp.h>
  19
  20 #include <asm/abs_addr.h>
  21 #include <asm/machdep.h>
  22 #include <asm/mmu.h>
  23 #include <asm/mmu_context.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/tlbflush.h>
  26 #include <asm/tlb.h>
  27 #include <asm/cputable.h>
  28 #include <asm/udbg.h>
  29 #include <asm/kexec.h>
  30 #include <asm/ppc-opcode.h>
  31
  32 #ifdef DEBUG_LOW
  33 #define DBG_LOW(fmt...) udbg_printf(fmt)
  34 #else
  35 #define DBG_LOW(fmt...)
  36 #endif
  37
  38 #define HPTE_LOCK_BIT 3
  39
  40 DEFINE_RAW_SPINLOCK(native_tlbie_lock);
  41
  42 static inline void __tlbie(unsigned long va, int psize, int ssize)
  43 {
  44         unsigned int penc;
  45
  46         /* clear top 16 bits, non SLS segment */
  47         va &= ~(0xffffULL << 48);
  48
  49         switch (psize) {
  50         case MMU_PAGE_4K:
  51                 va &= ~0xffful;
  52                 va |= ssize << 8;
  53                 asm volatile(ASM_FTR_IFCLR("tlbie %0,0", PPC_TLBIE(%1,%0), %2)
  54                              : : "r" (va), "r"(0), "i" (CPU_FTR_ARCH_206)
  55                              : "memory");
  56                 break;
  57         default:
  58                 penc = mmu_psize_defs[psize].penc;
  59                 va &= ~((1ul << mmu_psize_defs[psize].shift) - 1);
  60                 va |= penc << 12;
  61                 va |= ssize << 8;
  62                 va |= 1; /* L */
  63                 asm volatile(ASM_FTR_IFCLR("tlbie %0,1", PPC_TLBIE(%1,%0), %2)
  64                              : : "r" (va), "r"(0), "i" (CPU_FTR_ARCH_206)
  65                              : "memory");
  66                 break;
  67         }
  68 }
  69
  70 static inline void __tlbiel(unsigned long va, int psize, int ssize)
  71 {
  72         unsigned int penc;
  73
  74         /* clear top 16 bits, non SLS segment */
  75         va &= ~(0xffffULL << 48);
  76
  77         switch (psize) {
  78         case MMU_PAGE_4K:
  79                 va &= ~0xffful;
  80                 va |= ssize << 8;
  81                 asm volatile(".long 0x7c000224 | (%0 << 11) | (0 << 21)"
  82                              : : "r"(va) : "memory");
  83                 break;
  84         default:
  85                 penc = mmu_psize_defs[psize].penc;
  86                 va &= ~((1ul << mmu_psize_defs[psize].shift) - 1);
  87                 va |= penc << 12;
  88                 va |= ssize << 8;
  89                 va |= 1; /* L */
  90                 asm volatile(".long 0x7c000224 | (%0 << 11) | (1 << 21)"
  91                              : : "r"(va) : "memory");
  92                 break;
  93         }
  94
  95 }
  96
  97 static inline void tlbie(unsigned long va, int psize, int ssize, int local)
  98 {
  99         unsigned int use_local = local && mmu_has_feature(MMU_FTR_TLBIEL);
 100         int lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
 101
 102         if (use_local)
 103                 use_local = mmu_psize_defs[psize].tlbiel;
 104         if (lock_tlbie && !use_local)
 105                 raw_spin_lock(&native_tlbie_lock);
 106         asm volatile("ptesync": : :"memory");
 107         if (use_local) {
 108                 __tlbiel(va, psize, ssize);
 109                 asm volatile("ptesync": : :"memory");
 110         } else {
 111                 __tlbie(va, psize, ssize);
 112                 asm volatile("eieio; tlbsync; ptesync": : :"memory");
 113         }
 114         if (lock_tlbie && !use_local)
 115                 raw_spin_unlock(&native_tlbie_lock);
 116 }
 117
 118 static inline void native_lock_hpte(struct hash_pte *hptep)
 119 {
 120         unsigned long *word = &hptep->v;
 121
 122         while (1) {
 123                 if (!test_and_set_bit_lock(HPTE_LOCK_BIT, word))
 124                         break;
 125                 while(test_bit(HPTE_LOCK_BIT, word))
 126                         cpu_relax();
 127         }
 128 }
 129
 130 static inline void native_unlock_hpte(struct hash_pte *hptep)
 131 {
 132         unsigned long *word = &hptep->v;
 133
 134         clear_bit_unlock(HPTE_LOCK_BIT, word);
 135 }
 136
 137 static long native_hpte_insert(unsigned long hpte_group, unsigned long va,
 138                         unsigned long pa, unsigned long rflags,
 139                         unsigned long vflags, int psize, int ssize)
 140 {
 141         struct hash_pte *hptep = htab_address + hpte_group;
 142         unsigned long hpte_v, hpte_r;
 143         int i;
 144
 145         if (!(vflags & HPTE_V_BOLTED)) {
 146                 DBG_LOW("    insert(group=%lx, va=%016lx, pa=%016lx,"
 147                         " rflags=%lx, vflags=%lx, psize=%d)\n",
 148                         hpte_group, va, pa, rflags, vflags, psize);
 149         }
 150
 151         for (i = 0; i < HPTES_PER_GROUP; i++) {
 152                 if (! (hptep->v & HPTE_V_VALID)) {
 153                         /* retry with lock held */
 154                         native_lock_hpte(hptep);
 155                         if (! (hptep->v & HPTE_V_VALID))
 156                                 break;
 157                         native_unlock_hpte(hptep);
 158                 }
 159
 160                 hptep++;
 161         }
 162
 163         if (i == HPTES_PER_GROUP)
 164                 return -1;
 165
 166         hpte_v = hpte_encode_v(va, psize, ssize) | vflags | HPTE_V_VALID;
 167         hpte_r = hpte_encode_r(pa, psize) | rflags;
 168
 169         if (!(vflags & HPTE_V_BOLTED)) {
 170                 DBG_LOW(" i=%x hpte_v=%016lx, hpte_r=%016lx\n",
 171                         i, hpte_v, hpte_r);
 172         }
 173
 174         hptep->r = hpte_r;
 175         /* Guarantee the second dword is visible before the valid bit */
 176         eieio();
 177         /*
 178          * Now set the first dword including the valid bit
 179          * NOTE: this also unlocks the hpte
 180          */
 181         hptep->v = hpte_v;
 182
 183         __asm__ __volatile__ ("ptesync" : : : "memory");
 184
 185         return i | (!!(vflags & HPTE_V_SECONDARY) << 3);
 186 }
 187
 188 static long native_hpte_remove(unsigned long hpte_group)
 189 {
 190         struct hash_pte *hptep;
 191         int i;
 192         int slot_offset;
 193         unsigned long hpte_v;
 194
 195         DBG_LOW("    remove(group=%lx)\n", hpte_group);
 196
 197         /* pick a random entry to start at */
 198         slot_offset = mftb() & 0x7;
 199
 200         for (i = 0; i < HPTES_PER_GROUP; i++) {
 201                 hptep = htab_address + hpte_group + slot_offset;
 202                 hpte_v = hptep->v;
 203
 204                 if ((hpte_v & HPTE_V_VALID) && !(hpte_v & HPTE_V_BOLTED)) {
 205                         /* retry with lock held */
 206                         native_lock_hpte(hptep);
 207                         hpte_v = hptep->v;
 208                         if ((hpte_v & HPTE_V_VALID)
 209                             && !(hpte_v & HPTE_V_BOLTED))
 210                                 break;
 211                         native_unlock_hpte(hptep);
 212                 }
 213
 214                 slot_offset++;
 215                 slot_offset &= 0x7;
 216         }
 217
 218         if (i == HPTES_PER_GROUP)
 219                 return -1;
 220
 221         /* Invalidate the hpte. NOTE: this also unlocks it */
 222         hptep->v = 0;
 223
 224         return i;
 225 }
 226
 227 static long native_hpte_updatepp(unsigned long slot, unsigned long newpp,
 228                                  unsigned long va, int psize, int ssize,
 229                                  int local)
 230 {
 231         struct hash_pte *hptep = htab_address + slot;
 232         unsigned long hpte_v, want_v;
 233         int ret = 0;
 234
 235         want_v = hpte_encode_v(va, psize, ssize);
 236
 237         DBG_LOW("    update(va=%016lx, avpnv=%016lx, hash=%016lx, newpp=%x)",
 238                 va, want_v & HPTE_V_AVPN, slot, newpp);
 239
 240         native_lock_hpte(hptep);
 241
 242         hpte_v = hptep->v;
 243
 244         /* Even if we miss, we need to invalidate the TLB */
 245         if (!HPTE_V_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID)) {
 246                 DBG_LOW(" -> miss\n");
 247                 ret = -1;
 248         } else {
 249                 DBG_LOW(" -> hit\n");
 250                 /* Update the HPTE */
 251                 hptep->r = (hptep->r & ~(HPTE_R_PP | HPTE_R_N)) |
 252                         (newpp & (HPTE_R_PP | HPTE_R_N | HPTE_R_C));
 253         }
 254         native_unlock_hpte(hptep);
 255
 256         /* Ensure it is out of the tlb too. */
 257         tlbie(va, psize, ssize, local);
 258
 259         return ret;
 260 }
 261
 262 static long native_hpte_find(unsigned long va, int psize, int ssize)
 263 {
 264         struct hash_pte *hptep;
 265         unsigned long hash;
 266         unsigned long i;
 267         long slot;
 268         unsigned long want_v, hpte_v;
 269
 270         hash = hpt_hash(va, mmu_psize_defs[psize].shift, ssize);
 271         want_v = hpte_encode_v(va, psize, ssize);
 272
 273         /* Bolted mappings are only ever in the primary group */
 274         slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
 275         for (i = 0; i < HPTES_PER_GROUP; i++) {
 276                 hptep = htab_address + slot;
 277                 hpte_v = hptep->v;
 278
 279                 if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID))
 280                         /* HPTE matches */
 281                         return slot;
 282                 ++slot;
 283         }
 284
 285         return -1;
 286 }
 287
 288 /*
 289  * Update the page protection bits. Intended to be used to create
 290  * guard pages for kernel data structures on pages which are bolted
 291  * in the HPT. Assumes pages being operated on will not be stolen.
 292  *
 293  * No need to lock here because we should be the only user.
 294  */
 295 static void native_hpte_updateboltedpp(unsigned long newpp, unsigned long ea,
 296                                        int psize, int ssize)
 297 {
 298         unsigned long vsid, va;
 299         long slot;
 300         struct hash_pte *hptep;
 301
 302         vsid = get_kernel_vsid(ea, ssize);
 303         va = hpt_va(ea, vsid, ssize);
 304
 305         slot = native_hpte_find(va, psize, ssize);
 306         if (slot == -1)
 307                 panic("could not find page to bolt\n");
 308         hptep = htab_address + slot;
 309
 310         /* Update the HPTE */
 311         hptep->r = (hptep->r & ~(HPTE_R_PP | HPTE_R_N)) |
 312                 (newpp & (HPTE_R_PP | HPTE_R_N));
 313
 314         /* Ensure it is out of the tlb too. */
 315         tlbie(va, psize, ssize, 0);
 316 }
 317
 318 static void native_hpte_invalidate(unsigned long slot, unsigned long va,
 319                                    int psize, int ssize, int local)
 320 {
 321         struct hash_pte *hptep = htab_address + slot;
 322         unsigned long hpte_v;
 323         unsigned long want_v;
 324         unsigned long flags;
 325
 326         local_irq_save(flags);
 327
 328         DBG_LOW("    invalidate(va=%016lx, hash: %x)\n", va, slot);
 329
 330         want_v = hpte_encode_v(va, psize, ssize);
 331         native_lock_hpte(hptep);
 332         hpte_v = hptep->v;
 333
 334         /* Even if we miss, we need to invalidate the TLB */
 335         if (!HPTE_V_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID))
 336                 native_unlock_hpte(hptep);
 337         else
 338                 /* Invalidate the hpte. NOTE: this also unlocks it */
 339                 hptep->v = 0;
 340
 341         /* Invalidate the TLB */
 342         tlbie(va, psize, ssize, local);
 343
 344         local_irq_restore(flags);
 345 }
 346
 347 #define LP_SHIFT        12
 348 #define LP_BITS         8
 349 #define LP_MASK(i)      ((0xFF >> (i)) << LP_SHIFT)
 350
 351 static void hpte_decode(struct hash_pte *hpte, unsigned long slot,
 352                         int *psize, int *ssize, unsigned long *va)
 353 {
 354         unsigned long hpte_r = hpte->r;
 355         unsigned long hpte_v = hpte->v;
 356         unsigned long avpn;
 357         int i, size, shift, penc;
 358
 359         if (!(hpte_v & HPTE_V_LARGE))
 360                 size = MMU_PAGE_4K;
 361         else {
 362                 for (i = 0; i < LP_BITS; i++) {
 363                         if ((hpte_r & LP_MASK(i+1)) == LP_MASK(i+1))
 364                                 break;
 365                 }
 366                 penc = LP_MASK(i+1) >> LP_SHIFT;
 367                 for (size = 0; size < MMU_PAGE_COUNT; size++) {
 368
 369                         /* 4K pages are not represented by LP */
 370                         if (size == MMU_PAGE_4K)
 371                                 continue;
 372
 373                         /* valid entries have a shift value */
 374                         if (!mmu_psize_defs[size].shift)
 375                                 continue;
 376
 377                         if (penc == mmu_psize_defs[size].penc)
 378                                 break;
 379                 }
 380         }
 381
 382         /* This works for all page sizes, and for 256M and 1T segments */
 383         shift = mmu_psize_defs[size].shift;
 384         avpn = (HPTE_V_AVPN_VAL(hpte_v) & ~mmu_psize_defs[size].avpnm) << 23;
 385
 386         if (shift < 23) {
 387                 unsigned long vpi, vsid, pteg;
 388
 389                 pteg = slot / HPTES_PER_GROUP;
 390                 if (hpte_v & HPTE_V_SECONDARY)
 391                         pteg = ~pteg;
 392                 switch (hpte_v >> HPTE_V_SSIZE_SHIFT) {
 393                 case MMU_SEGSIZE_256M:
 394                         vpi = ((avpn >> 28) ^ pteg) & htab_hash_mask;
 395                         break;
 396                 case MMU_SEGSIZE_1T:
 397                         vsid = avpn >> 40;
 398                         vpi = (vsid ^ (vsid << 25) ^ pteg) & htab_hash_mask;
 399                         break;
 400                 default:
 401                         avpn = vpi = size = 0;
 402                 }
 403                 avpn |= (vpi << mmu_psize_defs[size].shift);
 404         }
 405
 406         *va = avpn;
 407         *psize = size;
 408         *ssize = hpte_v >> HPTE_V_SSIZE_SHIFT;
 409 }
 410
 411 /*
 412  * clear all mappings on kexec.  All cpus are in real mode (or they will
 413  * be when they isi), and we are the only one left.  We rely on our kernel
 414  * mapping being 0xC0's and the hardware ignoring those two real bits.
 415  *
 416  * TODO: add batching support when enabled.  remember, no dynamic memory here,
 417  * athough there is the control page available...
 418  */
 419 static void native_hpte_clear(void)
 420 {
 421         unsigned long slot, slots, flags;
 422         struct hash_pte *hptep = htab_address;
 423         unsigned long hpte_v, va;
 424         unsigned long pteg_count;
 425         int psize, ssize;
 426
 427         pteg_count = htab_hash_mask + 1;
 428
 429         local_irq_save(flags);
 430
 431         /* we take the tlbie lock and hold it.  Some hardware will
 432          * deadlock if we try to tlbie from two processors at once.
 433          */
 434         raw_spin_lock(&native_tlbie_lock);
 435
 436         slots = pteg_count * HPTES_PER_GROUP;
 437
 438         for (slot = 0; slot < slots; slot++, hptep++) {
 439                 /*
 440                  * we could lock the pte here, but we are the only cpu
 441                  * running,  right?  and for crash dump, we probably
 442                  * don't want to wait for a maybe bad cpu.
 443                  */
 444                 hpte_v = hptep->v;
 445
 446                 /*
 447                  * Call __tlbie() here rather than tlbie() since we
 448                  * already hold the native_tlbie_lock.
 449                  */
 450                 if (hpte_v & HPTE_V_VALID) {
 451                         hpte_decode(hptep, slot, &psize, &ssize, &va);
 452                         hptep->v = 0;
 453                         __tlbie(va, psize, ssize);
 454                 }
 455         }
 456
 457         asm volatile("eieio; tlbsync; ptesync":::"memory");
 458         raw_spin_unlock(&native_tlbie_lock);
 459         local_irq_restore(flags);
 460 }
 461
 462 /*
 463  * Batched hash table flush, we batch the tlbie's to avoid taking/releasing
 464  * the lock all the time
 465  */
 466 static void native_flush_hash_range(unsigned long number, int local)
 467 {
 468         unsigned long va, hash, index, hidx, shift, slot;
 469         struct hash_pte *hptep;
 470         unsigned long hpte_v;
 471         unsigned long want_v;
 472         unsigned long flags;
 473         real_pte_t pte;
 474         struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
 475         unsigned long psize = batch->psize;
 476         int ssize = batch->ssize;
 477         int i;
 478
 479         local_irq_save(flags);
 480
 481         for (i = 0; i < number; i++) {
 482                 va = batch->vaddr[i];
 483                 pte = batch->pte[i];
 484
 485                 pte_iterate_hashed_subpages(pte, psize, va, index, shift) {
 486                         hash = hpt_hash(va, shift, ssize);
 487                         hidx = __rpte_to_hidx(pte, index);
 488                         if (hidx & _PTEIDX_SECONDARY)
 489                                 hash = ~hash;
 490                         slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
 491                         slot += hidx & _PTEIDX_GROUP_IX;
 492                         hptep = htab_address + slot;
 493                         want_v = hpte_encode_v(va, psize, ssize);
 494                         native_lock_hpte(hptep);
 495                         hpte_v = hptep->v;
 496                         if (!HPTE_V_COMPARE(hpte_v, want_v) ||
 497                             !(hpte_v & HPTE_V_VALID))
 498                                 native_unlock_hpte(hptep);
 499                         else
 500                                 hptep->v = 0;
 501                 } pte_iterate_hashed_end();
 502         }
 503
 504         if (mmu_has_feature(MMU_FTR_TLBIEL) &&
 505             mmu_psize_defs[psize].tlbiel && local) {
 506                 asm volatile("ptesync":::"memory");
 507                 for (i = 0; i < number; i++) {
 508                         va = batch->vaddr[i];
 509                         pte = batch->pte[i];
 510
 511                         pte_iterate_hashed_subpages(pte, psize, va, index,
 512                                                     shift) {
 513                                 __tlbiel(va, psize, ssize);
 514                         } pte_iterate_hashed_end();
 515                 }
 516                 asm volatile("ptesync":::"memory");
 517         } else {
 518                 int lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
 519
 520                 if (lock_tlbie)
 521                         raw_spin_lock(&native_tlbie_lock);
 522
 523                 asm volatile("ptesync":::"memory");
 524                 for (i = 0; i < number; i++) {
 525                         va = batch->vaddr[i];
 526                         pte = batch->pte[i];
 527
 528                         pte_iterate_hashed_subpages(pte, psize, va, index,
 529                                                     shift) {
 530                                 __tlbie(va, psize, ssize);
 531                         } pte_iterate_hashed_end();
 532                 }
 533                 asm volatile("eieio; tlbsync; ptesync":::"memory");
 534
 535                 if (lock_tlbie)
 536                         raw_spin_unlock(&native_tlbie_lock);
 537         }
 538
 539         local_irq_restore(flags);
 540 }
 541
 542 #ifdef CONFIG_PPC_PSERIES
 543 /* Disable TLB batching on nighthawk */
 544 static inline int tlb_batching_enabled(void)
 545 {
 546         struct device_node *root = of_find_node_by_path("/");
 547         int enabled = 1;
 548
 549         if (root) {
 550                 const char *model = of_get_property(root, "model", NULL);
 551                 if (model && !strcmp(model, "IBM,9076-N81"))
 552                         enabled = 0;
 553                 of_node_put(root);
 554         }
 555
 556         return enabled;
 557 }
 558 #else
 559 static inline int tlb_batching_enabled(void)
 560 {
 561         return 1;
 562 }
 563 #endif
 564
 565 void __init hpte_init_native(void)
 566 {
 567         ppc_md.hpte_invalidate  = native_hpte_invalidate;
 568         ppc_md.hpte_updatepp    = native_hpte_updatepp;
 569         ppc_md.hpte_updateboltedpp = native_hpte_updateboltedpp;
 570         ppc_md.hpte_insert      = native_hpte_insert;
 571         ppc_md.hpte_remove      = native_hpte_remove;
 572         ppc_md.hpte_clear_all   = native_hpte_clear;
 573         if (tlb_batching_enabled())
 574                 ppc_md.flush_hash_range = native_flush_hash_range;
 575 }