arch/ppc64/mm/hash_native.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 #include <linux/spinlock.h>
  13 #include <linux/bitops.h>
  14 #include <linux/threads.h>
  15 #include <linux/smp.h>
  16
  17 #include <asm/abs_addr.h>
  18 #include <asm/machdep.h>
  19 #include <asm/mmu.h>
  20 #include <asm/mmu_context.h>
  21 #include <asm/pgtable.h>
  22 #include <asm/tlbflush.h>
  23 #include <asm/tlb.h>
  24 #include <asm/cputable.h>
  25
  26 #define HPTE_LOCK_BIT 3
  27
  28 static DEFINE_SPINLOCK(native_tlbie_lock);
  29
  30 static inline void native_lock_hpte(HPTE *hptep)
  31 {
  32         unsigned long *word = &hptep->dw0.dword0;
  33
  34         while (1) {
  35                 if (!test_and_set_bit(HPTE_LOCK_BIT, word))
  36                         break;
  37                 while(test_bit(HPTE_LOCK_BIT, word))
  38                         cpu_relax();
  39         }
  40 }
  41
  42 static inline void native_unlock_hpte(HPTE *hptep)
  43 {
  44         unsigned long *word = &hptep->dw0.dword0;
  45
  46         asm volatile("lwsync":::"memory");
  47         clear_bit(HPTE_LOCK_BIT, word);
  48 }
  49
  50 long native_hpte_insert(unsigned long hpte_group, unsigned long va,
  51                         unsigned long prpn, int secondary,
  52                         unsigned long hpteflags, int bolted, int large)
  53 {
  54         unsigned long arpn = physRpn_to_absRpn(prpn);
  55         HPTE *hptep = htab_address + hpte_group;
  56         Hpte_dword0 dw0;
  57         HPTE lhpte;
  58         int i;
  59
  60         for (i = 0; i < HPTES_PER_GROUP; i++) {
  61                 dw0 = hptep->dw0.dw0;
  62
  63                 if (!dw0.v) {
  64                         /* retry with lock held */
  65                         native_lock_hpte(hptep);
  66                         dw0 = hptep->dw0.dw0;
  67                         if (!dw0.v)
  68                                 break;
  69                         native_unlock_hpte(hptep);
  70                 }
  71
  72                 hptep++;
  73         }
  74
  75         if (i == HPTES_PER_GROUP)
  76                 return -1;
  77
  78         lhpte.dw1.dword1      = 0;
  79         lhpte.dw1.dw1.rpn     = arpn;
  80         lhpte.dw1.flags.flags = hpteflags;
  81
  82         lhpte.dw0.dword0      = 0;
  83         lhpte.dw0.dw0.avpn    = va >> 23;
  84         lhpte.dw0.dw0.h       = secondary;
  85         lhpte.dw0.dw0.bolted  = bolted;
  86         lhpte.dw0.dw0.v       = 1;
  87
  88         if (large) {
  89                 lhpte.dw0.dw0.l = 1;
  90                 lhpte.dw0.dw0.avpn &= ~0x1UL;
  91         }
  92
  93         hptep->dw1.dword1 = lhpte.dw1.dword1;
  94
  95         /* Guarantee the second dword is visible before the valid bit */
  96         __asm__ __volatile__ ("eieio" : : : "memory");
  97
  98         /*
  99          * Now set the first dword including the valid bit
 100          * NOTE: this also unlocks the hpte
 101          */
 102         hptep->dw0.dword0 = lhpte.dw0.dword0;
 103
 104         __asm__ __volatile__ ("ptesync" : : : "memory");
 105
 106         return i | (secondary << 3);
 107 }
 108
 109 static long native_hpte_remove(unsigned long hpte_group)
 110 {
 111         HPTE *hptep;
 112         Hpte_dword0 dw0;
 113         int i;
 114         int slot_offset;
 115
 116         /* pick a random entry to start at */
 117         slot_offset = mftb() & 0x7;
 118
 119         for (i = 0; i < HPTES_PER_GROUP; i++) {
 120                 hptep = htab_address + hpte_group + slot_offset;
 121                 dw0 = hptep->dw0.dw0;
 122
 123                 if (dw0.v && !dw0.bolted) {
 124                         /* retry with lock held */
 125                         native_lock_hpte(hptep);
 126                         dw0 = hptep->dw0.dw0;
 127                         if (dw0.v && !dw0.bolted)
 128                                 break;
 129                         native_unlock_hpte(hptep);
 130                 }
 131
 132                 slot_offset++;
 133                 slot_offset &= 0x7;
 134         }
 135
 136         if (i == HPTES_PER_GROUP)
 137                 return -1;
 138
 139         /* Invalidate the hpte. NOTE: this also unlocks it */
 140         hptep->dw0.dword0 = 0;
 141
 142         return i;
 143 }
 144
 145 static inline void set_pp_bit(unsigned long pp, HPTE *addr)
 146 {
 147         unsigned long old;
 148         unsigned long *p = &addr->dw1.dword1;
 149
 150         __asm__ __volatile__(
 151         "1:     ldarx   %0,0,%3\n\
 152                 rldimi  %0,%2,0,61\n\
 153                 stdcx.  %0,0,%3\n\
 154                 bne     1b"
 155         : "=&r" (old), "=m" (*p)
 156         : "r" (pp), "r" (p), "m" (*p)
 157         : "cc");
 158 }
 159
 160 /*
 161  * Only works on small pages. Yes its ugly to have to check each slot in
 162  * the group but we only use this during bootup.
 163  */
 164 static long native_hpte_find(unsigned long vpn)
 165 {
 166         HPTE *hptep;
 167         unsigned long hash;
 168         unsigned long i, j;
 169         long slot;
 170         Hpte_dword0 dw0;
 171
 172         hash = hpt_hash(vpn, 0);
 173
 174         for (j = 0; j < 2; j++) {
 175                 slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
 176                 for (i = 0; i < HPTES_PER_GROUP; i++) {
 177                         hptep = htab_address + slot;
 178                         dw0 = hptep->dw0.dw0;
 179
 180                         if ((dw0.avpn == (vpn >> 11)) && dw0.v &&
 181                             (dw0.h == j)) {
 182                                 /* HPTE matches */
 183                                 if (j)
 184                                         slot = -slot;
 185                                 return slot;
 186                         }
 187                         ++slot;
 188                 }
 189                 hash = ~hash;
 190         }
 191
 192         return -1;
 193 }
 194
 195 static long native_hpte_updatepp(unsigned long slot, unsigned long newpp,
 196                                  unsigned long va, int large, int local)
 197 {
 198         HPTE *hptep = htab_address + slot;
 199         Hpte_dword0 dw0;
 200         unsigned long avpn = va >> 23;
 201         int ret = 0;
 202
 203         if (large)
 204                 avpn &= ~0x1UL;
 205
 206         native_lock_hpte(hptep);
 207
 208         dw0 = hptep->dw0.dw0;
 209
 210         /* Even if we miss, we need to invalidate the TLB */
 211         if ((dw0.avpn != avpn) || !dw0.v) {
 212                 native_unlock_hpte(hptep);
 213                 ret = -1;
 214         } else {
 215                 set_pp_bit(newpp, hptep);
 216                 native_unlock_hpte(hptep);
 217         }
 218
 219         /* Ensure it is out of the tlb too */
 220         if (cpu_has_feature(CPU_FTR_TLBIEL) && !large && local) {
 221                 tlbiel(va);
 222         } else {
 223                 int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
 224
 225                 if (lock_tlbie)
 226                         spin_lock(&native_tlbie_lock);
 227                 tlbie(va, large);
 228                 if (lock_tlbie)
 229                         spin_unlock(&native_tlbie_lock);
 230         }
 231
 232         return ret;
 233 }
 234
 235 /*
 236  * Update the page protection bits. Intended to be used to create
 237  * guard pages for kernel data structures on pages which are bolted
 238  * in the HPT. Assumes pages being operated on will not be stolen.
 239  * Does not work on large pages.
 240  *
 241  * No need to lock here because we should be the only user.
 242  */
 243 static void native_hpte_updateboltedpp(unsigned long newpp, unsigned long ea)
 244 {
 245         unsigned long vsid, va, vpn, flags = 0;
 246         long slot;
 247         HPTE *hptep;
 248         int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
 249
 250         vsid = get_kernel_vsid(ea);
 251         va = (vsid << 28) | (ea & 0x0fffffff);
 252         vpn = va >> PAGE_SHIFT;
 253
 254         slot = native_hpte_find(vpn);
 255         if (slot == -1)
 256                 panic("could not find page to bolt\n");
 257         hptep = htab_address + slot;
 258
 259         set_pp_bit(newpp, hptep);
 260
 261         /* Ensure it is out of the tlb too */
 262         if (lock_tlbie)
 263                 spin_lock_irqsave(&native_tlbie_lock, flags);
 264         tlbie(va, 0);
 265         if (lock_tlbie)
 266                 spin_unlock_irqrestore(&native_tlbie_lock, flags);
 267 }
 268
 269 static void native_hpte_invalidate(unsigned long slot, unsigned long va,
 270                                     int large, int local)
 271 {
 272         HPTE *hptep = htab_address + slot;
 273         Hpte_dword0 dw0;
 274         unsigned long avpn = va >> 23;
 275         unsigned long flags;
 276         int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
 277
 278         if (large)
 279                 avpn &= ~0x1UL;
 280
 281         local_irq_save(flags);
 282         native_lock_hpte(hptep);
 283
 284         dw0 = hptep->dw0.dw0;
 285
 286         /* Even if we miss, we need to invalidate the TLB */
 287         if ((dw0.avpn != avpn) || !dw0.v) {
 288                 native_unlock_hpte(hptep);
 289         } else {
 290                 /* Invalidate the hpte. NOTE: this also unlocks it */
 291                 hptep->dw0.dword0 = 0;
 292         }
 293
 294         /* Invalidate the tlb */
 295         if (cpu_has_feature(CPU_FTR_TLBIEL) && !large && local) {
 296                 tlbiel(va);
 297         } else {
 298                 if (lock_tlbie)
 299                         spin_lock(&native_tlbie_lock);
 300                 tlbie(va, large);
 301                 if (lock_tlbie)
 302                         spin_unlock(&native_tlbie_lock);
 303         }
 304         local_irq_restore(flags);
 305 }
 306
 307 static void native_flush_hash_range(unsigned long context,
 308                                     unsigned long number, int local)
 309 {
 310         unsigned long vsid, vpn, va, hash, secondary, slot, flags, avpn;
 311         int i, j;
 312         HPTE *hptep;
 313         Hpte_dword0 dw0;
 314         struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
 315
 316         /* XXX fix for large ptes */
 317         unsigned long large = 0;
 318
 319         local_irq_save(flags);
 320
 321         j = 0;
 322         for (i = 0; i < number; i++) {
 323                 if (batch->addr[i] < KERNELBASE)
 324                         vsid = get_vsid(context, batch->addr[i]);
 325                 else
 326                         vsid = get_kernel_vsid(batch->addr[i]);
 327
 328                 va = (vsid << 28) | (batch->addr[i] & 0x0fffffff);
 329                 batch->vaddr[j] = va;
 330                 if (large)
 331                         vpn = va >> HPAGE_SHIFT;
 332                 else
 333                         vpn = va >> PAGE_SHIFT;
 334                 hash = hpt_hash(vpn, large);
 335                 secondary = (pte_val(batch->pte[i]) & _PAGE_SECONDARY) >> 15;
 336                 if (secondary)
 337                         hash = ~hash;
 338                 slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
 339                 slot += (pte_val(batch->pte[i]) & _PAGE_GROUP_IX) >> 12;
 340
 341                 hptep = htab_address + slot;
 342
 343                 avpn = va >> 23;
 344                 if (large)
 345                         avpn &= ~0x1UL;
 346
 347                 native_lock_hpte(hptep);
 348
 349                 dw0 = hptep->dw0.dw0;
 350
 351                 /* Even if we miss, we need to invalidate the TLB */
 352                 if ((dw0.avpn != avpn) || !dw0.v) {
 353                         native_unlock_hpte(hptep);
 354                 } else {
 355                         /* Invalidate the hpte. NOTE: this also unlocks it */
 356                         hptep->dw0.dword0 = 0;
 357                 }
 358
 359                 j++;
 360         }
 361
 362         if (cpu_has_feature(CPU_FTR_TLBIEL) && !large && local) {
 363                 asm volatile("ptesync":::"memory");
 364
 365                 for (i = 0; i < j; i++)
 366                         __tlbiel(batch->vaddr[i]);
 367
 368                 asm volatile("ptesync":::"memory");
 369         } else {
 370                 int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
 371
 372                 if (lock_tlbie)
 373                         spin_lock(&native_tlbie_lock);
 374
 375                 asm volatile("ptesync":::"memory");
 376
 377                 for (i = 0; i < j; i++)
 378                         __tlbie(batch->vaddr[i], 0);
 379
 380                 asm volatile("eieio; tlbsync; ptesync":::"memory");
 381
 382                 if (lock_tlbie)
 383                         spin_unlock(&native_tlbie_lock);
 384         }
 385
 386         local_irq_restore(flags);
 387 }
 388
 389 #ifdef CONFIG_PPC_PSERIES
 390 /* Disable TLB batching on nighthawk */
 391 static inline int tlb_batching_enabled(void)
 392 {
 393         struct device_node *root = of_find_node_by_path("/");
 394         int enabled = 1;
 395
 396         if (root) {
 397                 const char *model = get_property(root, "model", NULL);
 398                 if (model && !strcmp(model, "IBM,9076-N81"))
 399                         enabled = 0;
 400                 of_node_put(root);
 401         }
 402
 403         return enabled;
 404 }
 405 #else
 406 static inline int tlb_batching_enabled(void)
 407 {
 408         return 1;
 409 }
 410 #endif
 411
 412 void hpte_init_native(void)
 413 {
 414         ppc_md.hpte_invalidate  = native_hpte_invalidate;
 415         ppc_md.hpte_updatepp    = native_hpte_updatepp;
 416         ppc_md.hpte_updateboltedpp = native_hpte_updateboltedpp;
 417         ppc_md.hpte_insert      = native_hpte_insert;
 418         ppc_md.hpte_remove      = native_hpte_remove;
 419         if (tlb_batching_enabled())
 420                 ppc_md.flush_hash_range = native_flush_hash_range;
 421         htab_finish_init();
 422 }