arch/ia64/mm/tlb.c

   1 /*
   2  * TLB support routines.
   3  *
   4  * Copyright (C) 1998-2001, 2003 Hewlett-Packard Co
   5  *      David Mosberger-Tang <davidm@hpl.hp.com>
   6  *
   7  * 08/02/00 A. Mallick <asit.k.mallick@intel.com>
   8  *              Modified RID allocation for SMP
   9  *          Goutham Rao <goutham.rao@intel.com>
  10  *              IPI based ptc implementation and A-step IPI implementation.
  11  * Rohit Seth <rohit.seth@intel.com>
  12  * Ken Chen <kenneth.w.chen@intel.com>
  13  * Christophe de Dinechin <ddd@hp.com>: Avoid ptc.e on memory allocation
  14  * Copyright (C) 2007 Intel Corp
  15  *      Fenghua Yu <fenghua.yu@intel.com>
  16  *      Add multiple ptc.g/ptc.ga instruction support in global tlb purge.
  17  */
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/smp.h>
  23 #include <linux/mm.h>
  24 #include <linux/memblock.h>
  25 #include <linux/slab.h>
  26
  27 #include <asm/delay.h>
  28 #include <asm/mmu_context.h>
  29 #include <asm/pgalloc.h>
  30 #include <asm/pal.h>
  31 #include <asm/tlbflush.h>
  32 #include <asm/dma.h>
  33 #include <asm/processor.h>
  34 #include <asm/sal.h>
  35 #include <asm/tlb.h>
  36
  37 static struct {
  38         u64 mask;               /* mask of supported purge page-sizes */
  39         unsigned long max_bits; /* log2 of largest supported purge page-size */
  40 } purge;
  41
  42 struct ia64_ctx ia64_ctx = {
  43         .lock = __SPIN_LOCK_UNLOCKED(ia64_ctx.lock),
  44         .next = 1,
  45         .max_ctx = ~0U
  46 };
  47
  48 DEFINE_PER_CPU(u8, ia64_need_tlb_flush);
  49 DEFINE_PER_CPU(u8, ia64_tr_num);  /*Number of TR slots in current processor*/
  50 DEFINE_PER_CPU(u8, ia64_tr_used); /*Max Slot number used by kernel*/
  51
  52 struct ia64_tr_entry *ia64_idtrs[NR_CPUS];
  53
  54 /*
  55  * Initializes the ia64_ctx.bitmap array based on max_ctx+1.
  56  * Called after cpu_init() has setup ia64_ctx.max_ctx based on
  57  * maximum RID that is supported by boot CPU.
  58  */
  59 void __init
  60 mmu_context_init (void)
  61 {
  62         ia64_ctx.bitmap = memblock_alloc((ia64_ctx.max_ctx + 1) >> 3,
  63                                          SMP_CACHE_BYTES);
  64         if (!ia64_ctx.bitmap)
  65                 panic("%s: Failed to allocate %u bytes\n", __func__,
  66                       (ia64_ctx.max_ctx + 1) >> 3);
  67         ia64_ctx.flushmap = memblock_alloc((ia64_ctx.max_ctx + 1) >> 3,
  68                                            SMP_CACHE_BYTES);
  69         if (!ia64_ctx.flushmap)
  70                 panic("%s: Failed to allocate %u bytes\n", __func__,
  71                       (ia64_ctx.max_ctx + 1) >> 3);
  72 }
  73
  74 /*
  75  * Acquire the ia64_ctx.lock before calling this function!
  76  */
  77 void
  78 wrap_mmu_context (struct mm_struct *mm)
  79 {
  80         int i, cpu;
  81         unsigned long flush_bit;
  82
  83         for (i=0; i <= ia64_ctx.max_ctx / BITS_PER_LONG; i++) {
  84                 flush_bit = xchg(&ia64_ctx.flushmap[i], 0);
  85                 ia64_ctx.bitmap[i] ^= flush_bit;
  86         }
  87
  88         /* use offset at 300 to skip daemons */
  89         ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
  90                                 ia64_ctx.max_ctx, 300);
  91         ia64_ctx.limit = find_next_bit(ia64_ctx.bitmap,
  92                                 ia64_ctx.max_ctx, ia64_ctx.next);
  93
  94         /*
  95          * can't call flush_tlb_all() here because of race condition
  96          * with O(1) scheduler [EF]
  97          */
  98         cpu = get_cpu(); /* prevent preemption/migration */
  99         for_each_online_cpu(i)
 100                 if (i != cpu)
 101                         per_cpu(ia64_need_tlb_flush, i) = 1;
 102         put_cpu();
 103         local_flush_tlb_all();
 104 }
 105
 106 /*
 107  * Implement "spinaphores" ... like counting semaphores, but they
 108  * spin instead of sleeping.  If there are ever any other users for
 109  * this primitive it can be moved up to a spinaphore.h header.
 110  */
 111 struct spinaphore {
 112         unsigned long   ticket;
 113         unsigned long   serve;
 114 };
 115
 116 static inline void spinaphore_init(struct spinaphore *ss, int val)
 117 {
 118         ss->ticket = 0;
 119         ss->serve = val;
 120 }
 121
 122 static inline void down_spin(struct spinaphore *ss)
 123 {
 124         unsigned long t = ia64_fetchadd(1, &ss->ticket, acq), serve;
 125
 126         if (time_before(t, ss->serve))
 127                 return;
 128
 129         ia64_invala();
 130
 131         for (;;) {
 132                 asm volatile ("ld8.c.nc %0=[%1]" : "=r"(serve) : "r"(&ss->serve) : "memory");
 133                 if (time_before(t, serve))
 134                         return;
 135                 cpu_relax();
 136         }
 137 }
 138
 139 static inline void up_spin(struct spinaphore *ss)
 140 {
 141         ia64_fetchadd(1, &ss->serve, rel);
 142 }
 143
 144 static struct spinaphore ptcg_sem;
 145 static u16 nptcg = 1;
 146 static int need_ptcg_sem = 1;
 147 static int toolatetochangeptcgsem = 0;
 148
 149 /*
 150  * Kernel parameter "nptcg=" overrides max number of concurrent global TLB
 151  * purges which is reported from either PAL or SAL PALO.
 152  *
 153  * We don't have sanity checking for nptcg value. It's the user's responsibility
 154  * for valid nptcg value on the platform. Otherwise, kernel may hang in some
 155  * cases.
 156  */
 157 static int __init
 158 set_nptcg(char *str)
 159 {
 160         int value = 0;
 161
 162         get_option(&str, &value);
 163         setup_ptcg_sem(value, NPTCG_FROM_KERNEL_PARAMETER);
 164
 165         return 1;
 166 }
 167
 168 __setup("nptcg=", set_nptcg);
 169
 170 /*
 171  * Maximum number of simultaneous ptc.g purges in the system can
 172  * be defined by PAL_VM_SUMMARY (in which case we should take
 173  * the smallest value for any cpu in the system) or by the PAL
 174  * override table (in which case we should ignore the value from
 175  * PAL_VM_SUMMARY).
 176  *
 177  * Kernel parameter "nptcg=" overrides maximum number of simultanesous ptc.g
 178  * purges defined in either PAL_VM_SUMMARY or PAL override table. In this case,
 179  * we should ignore the value from either PAL_VM_SUMMARY or PAL override table.
 180  *
 181  * Complicating the logic here is the fact that num_possible_cpus()
 182  * isn't fully setup until we start bringing cpus online.
 183  */
 184 void
 185 setup_ptcg_sem(int max_purges, int nptcg_from)
 186 {
 187         static int kp_override;
 188         static int palo_override;
 189         static int firstcpu = 1;
 190
 191         if (toolatetochangeptcgsem) {
 192                 if (nptcg_from == NPTCG_FROM_PAL && max_purges == 0)
 193                         BUG_ON(1 < nptcg);
 194                 else
 195                         BUG_ON(max_purges < nptcg);
 196                 return;
 197         }
 198
 199         if (nptcg_from == NPTCG_FROM_KERNEL_PARAMETER) {
 200                 kp_override = 1;
 201                 nptcg = max_purges;
 202                 goto resetsema;
 203         }
 204         if (kp_override) {
 205                 need_ptcg_sem = num_possible_cpus() > nptcg;
 206                 return;
 207         }
 208
 209         if (nptcg_from == NPTCG_FROM_PALO) {
 210                 palo_override = 1;
 211
 212                 /* In PALO max_purges == 0 really means it! */
 213                 if (max_purges == 0)
 214                         panic("Whoa! Platform does not support global TLB purges.\n");
 215                 nptcg = max_purges;
 216                 if (nptcg == PALO_MAX_TLB_PURGES) {
 217                         need_ptcg_sem = 0;
 218                         return;
 219                 }
 220                 goto resetsema;
 221         }
 222         if (palo_override) {
 223                 if (nptcg != PALO_MAX_TLB_PURGES)
 224                         need_ptcg_sem = (num_possible_cpus() > nptcg);
 225                 return;
 226         }
 227
 228         /* In PAL_VM_SUMMARY max_purges == 0 actually means 1 */
 229         if (max_purges == 0) max_purges = 1;
 230
 231         if (firstcpu) {
 232                 nptcg = max_purges;
 233                 firstcpu = 0;
 234         }
 235         if (max_purges < nptcg)
 236                 nptcg = max_purges;
 237         if (nptcg == PAL_MAX_PURGES) {
 238                 need_ptcg_sem = 0;
 239                 return;
 240         } else
 241                 need_ptcg_sem = (num_possible_cpus() > nptcg);
 242
 243 resetsema:
 244         spinaphore_init(&ptcg_sem, max_purges);
 245 }
 246
 247 void
 248 ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
 249                        unsigned long end, unsigned long nbits)
 250 {
 251         struct mm_struct *active_mm = current->active_mm;
 252
 253         toolatetochangeptcgsem = 1;
 254
 255         if (mm != active_mm) {
 256                 /* Restore region IDs for mm */
 257                 if (mm && active_mm) {
 258                         activate_context(mm);
 259                 } else {
 260                         flush_tlb_all();
 261                         return;
 262                 }
 263         }
 264
 265         if (need_ptcg_sem)
 266                 down_spin(&ptcg_sem);
 267
 268         do {
 269                 /*
 270                  * Flush ALAT entries also.
 271                  */
 272                 ia64_ptcga(start, (nbits << 2));
 273                 ia64_srlz_i();
 274                 start += (1UL << nbits);
 275         } while (start < end);
 276
 277         if (need_ptcg_sem)
 278                 up_spin(&ptcg_sem);
 279
 280         if (mm != active_mm) {
 281                 activate_context(active_mm);
 282         }
 283 }
 284
 285 void
 286 local_flush_tlb_all (void)
 287 {
 288         unsigned long i, j, flags, count0, count1, stride0, stride1, addr;
 289
 290         addr    = local_cpu_data->ptce_base;
 291         count0  = local_cpu_data->ptce_count[0];
 292         count1  = local_cpu_data->ptce_count[1];
 293         stride0 = local_cpu_data->ptce_stride[0];
 294         stride1 = local_cpu_data->ptce_stride[1];
 295
 296         local_irq_save(flags);
 297         for (i = 0; i < count0; ++i) {
 298                 for (j = 0; j < count1; ++j) {
 299                         ia64_ptce(addr);
 300                         addr += stride1;
 301                 }
 302                 addr += stride0;
 303         }
 304         local_irq_restore(flags);
 305         ia64_srlz_i();                  /* srlz.i implies srlz.d */
 306 }
 307
 308 static void
 309 __flush_tlb_range (struct vm_area_struct *vma, unsigned long start,
 310                  unsigned long end)
 311 {
 312         struct mm_struct *mm = vma->vm_mm;
 313         unsigned long size = end - start;
 314         unsigned long nbits;
 315
 316 #ifndef CONFIG_SMP
 317         if (mm != current->active_mm) {
 318                 mm->context = 0;
 319                 return;
 320         }
 321 #endif
 322
 323         nbits = ia64_fls(size + 0xfff);
 324         while (unlikely (((1UL << nbits) & purge.mask) == 0) &&
 325                         (nbits < purge.max_bits))
 326                 ++nbits;
 327         if (nbits > purge.max_bits)
 328                 nbits = purge.max_bits;
 329         start &= ~((1UL << nbits) - 1);
 330
 331         preempt_disable();
 332 #ifdef CONFIG_SMP
 333         if (mm != current->active_mm || cpumask_weight(mm_cpumask(mm)) != 1) {
 334                 platform_global_tlb_purge(mm, start, end, nbits);
 335                 preempt_enable();
 336                 return;
 337         }
 338 #endif
 339         do {
 340                 ia64_ptcl(start, (nbits<<2));
 341                 start += (1UL << nbits);
 342         } while (start < end);
 343         preempt_enable();
 344         ia64_srlz_i();                  /* srlz.i implies srlz.d */
 345 }
 346
 347 void flush_tlb_range(struct vm_area_struct *vma,
 348                 unsigned long start, unsigned long end)
 349 {
 350         if (unlikely(end - start >= 1024*1024*1024*1024UL
 351                         || REGION_NUMBER(start) != REGION_NUMBER(end - 1))) {
 352                 /*
 353                  * If we flush more than a tera-byte or across regions, we're
 354                  * probably better off just flushing the entire TLB(s).  This
 355                  * should be very rare and is not worth optimizing for.
 356                  */
 357                 flush_tlb_all();
 358         } else {
 359                 /* flush the address range from the tlb */
 360                 __flush_tlb_range(vma, start, end);
 361                 /* flush the virt. page-table area mapping the addr range */
 362                 __flush_tlb_range(vma, ia64_thash(start), ia64_thash(end));
 363         }
 364 }
 365 EXPORT_SYMBOL(flush_tlb_range);
 366
 367 void ia64_tlb_init(void)
 368 {
 369         ia64_ptce_info_t uninitialized_var(ptce_info); /* GCC be quiet */
 370         u64 tr_pgbits;
 371         long status;
 372         pal_vm_info_1_u_t vm_info_1;
 373         pal_vm_info_2_u_t vm_info_2;
 374         int cpu = smp_processor_id();
 375
 376         if ((status = ia64_pal_vm_page_size(&tr_pgbits, &purge.mask)) != 0) {
 377                 printk(KERN_ERR "PAL_VM_PAGE_SIZE failed with status=%ld; "
 378                        "defaulting to architected purge page-sizes.\n", status);
 379                 purge.mask = 0x115557000UL;
 380         }
 381         purge.max_bits = ia64_fls(purge.mask);
 382
 383         ia64_get_ptce(&ptce_info);
 384         local_cpu_data->ptce_base = ptce_info.base;
 385         local_cpu_data->ptce_count[0] = ptce_info.count[0];
 386         local_cpu_data->ptce_count[1] = ptce_info.count[1];
 387         local_cpu_data->ptce_stride[0] = ptce_info.stride[0];
 388         local_cpu_data->ptce_stride[1] = ptce_info.stride[1];
 389
 390         local_flush_tlb_all();  /* nuke left overs from bootstrapping... */
 391         status = ia64_pal_vm_summary(&vm_info_1, &vm_info_2);
 392
 393         if (status) {
 394                 printk(KERN_ERR "ia64_pal_vm_summary=%ld\n", status);
 395                 per_cpu(ia64_tr_num, cpu) = 8;
 396                 return;
 397         }
 398         per_cpu(ia64_tr_num, cpu) = vm_info_1.pal_vm_info_1_s.max_itr_entry+1;
 399         if (per_cpu(ia64_tr_num, cpu) >
 400                                 (vm_info_1.pal_vm_info_1_s.max_dtr_entry+1))
 401                 per_cpu(ia64_tr_num, cpu) =
 402                                 vm_info_1.pal_vm_info_1_s.max_dtr_entry+1;
 403         if (per_cpu(ia64_tr_num, cpu) > IA64_TR_ALLOC_MAX) {
 404                 static int justonce = 1;
 405                 per_cpu(ia64_tr_num, cpu) = IA64_TR_ALLOC_MAX;
 406                 if (justonce) {
 407                         justonce = 0;
 408                         printk(KERN_DEBUG "TR register number exceeds "
 409                                "IA64_TR_ALLOC_MAX!\n");
 410                 }
 411         }
 412 }
 413
 414 /*
 415  * is_tr_overlap
 416  *
 417  * Check overlap with inserted TRs.
 418  */
 419 static int is_tr_overlap(struct ia64_tr_entry *p, u64 va, u64 log_size)
 420 {
 421         u64 tr_log_size;
 422         u64 tr_end;
 423         u64 va_rr = ia64_get_rr(va);
 424         u64 va_rid = RR_TO_RID(va_rr);
 425         u64 va_end = va + (1<<log_size) - 1;
 426
 427         if (va_rid != RR_TO_RID(p->rr))
 428                 return 0;
 429         tr_log_size = (p->itir & 0xff) >> 2;
 430         tr_end = p->ifa + (1<<tr_log_size) - 1;
 431
 432         if (va > tr_end || p->ifa > va_end)
 433                 return 0;
 434         return 1;
 435
 436 }
 437
 438 /*
 439  * ia64_insert_tr in virtual mode. Allocate a TR slot
 440  *
 441  * target_mask : 0x1 : itr, 0x2 : dtr, 0x3 : idtr
 442  *
 443  * va   : virtual address.
 444  * pte  : pte entries inserted.
 445  * log_size: range to be covered.
 446  *
 447  * Return value:  <0 :  error No.
 448  *
 449  *                >=0 : slot number allocated for TR.
 450  * Must be called with preemption disabled.
 451  */
 452 int ia64_itr_entry(u64 target_mask, u64 va, u64 pte, u64 log_size)
 453 {
 454         int i, r;
 455         unsigned long psr;
 456         struct ia64_tr_entry *p;
 457         int cpu = smp_processor_id();
 458
 459         if (!ia64_idtrs[cpu]) {
 460                 ia64_idtrs[cpu] = kmalloc_array(2 * IA64_TR_ALLOC_MAX,
 461                                                 sizeof(struct ia64_tr_entry),
 462                                                 GFP_KERNEL);
 463                 if (!ia64_idtrs[cpu])
 464                         return -ENOMEM;
 465         }
 466         r = -EINVAL;
 467         /*Check overlap with existing TR entries*/
 468         if (target_mask & 0x1) {
 469                 p = ia64_idtrs[cpu];
 470                 for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
 471                                                                 i++, p++) {
 472                         if (p->pte & 0x1)
 473                                 if (is_tr_overlap(p, va, log_size)) {
 474                                         printk(KERN_DEBUG "Overlapped Entry"
 475                                                 "Inserted for TR Register!!\n");
 476                                         goto out;
 477                         }
 478                 }
 479         }
 480         if (target_mask & 0x2) {
 481                 p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX;
 482                 for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
 483                                                                 i++, p++) {
 484                         if (p->pte & 0x1)
 485                                 if (is_tr_overlap(p, va, log_size)) {
 486                                         printk(KERN_DEBUG "Overlapped Entry"
 487                                                 "Inserted for TR Register!!\n");
 488                                         goto out;
 489                                 }
 490                 }
 491         }
 492
 493         for (i = IA64_TR_ALLOC_BASE; i < per_cpu(ia64_tr_num, cpu); i++) {
 494                 switch (target_mask & 0x3) {
 495                 case 1:
 496                         if (!((ia64_idtrs[cpu] + i)->pte & 0x1))
 497                                 goto found;
 498                         continue;
 499                 case 2:
 500                         if (!((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
 501                                 goto found;
 502                         continue;
 503                 case 3:
 504                         if (!((ia64_idtrs[cpu] + i)->pte & 0x1) &&
 505                             !((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
 506                                 goto found;
 507                         continue;
 508                 default:
 509                         r = -EINVAL;
 510                         goto out;
 511                 }
 512         }
 513 found:
 514         if (i >= per_cpu(ia64_tr_num, cpu))
 515                 return -EBUSY;
 516
 517         /*Record tr info for mca hander use!*/
 518         if (i > per_cpu(ia64_tr_used, cpu))
 519                 per_cpu(ia64_tr_used, cpu) = i;
 520
 521         psr = ia64_clear_ic();
 522         if (target_mask & 0x1) {
 523                 ia64_itr(0x1, i, va, pte, log_size);
 524                 ia64_srlz_i();
 525                 p = ia64_idtrs[cpu] + i;
 526                 p->ifa = va;
 527                 p->pte = pte;
 528                 p->itir = log_size << 2;
 529                 p->rr = ia64_get_rr(va);
 530         }
 531         if (target_mask & 0x2) {
 532                 ia64_itr(0x2, i, va, pte, log_size);
 533                 ia64_srlz_i();
 534                 p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i;
 535                 p->ifa = va;
 536                 p->pte = pte;
 537                 p->itir = log_size << 2;
 538                 p->rr = ia64_get_rr(va);
 539         }
 540         ia64_set_psr(psr);
 541         r = i;
 542 out:
 543         return r;
 544 }
 545 EXPORT_SYMBOL_GPL(ia64_itr_entry);
 546
 547 /*
 548  * ia64_purge_tr
 549  *
 550  * target_mask: 0x1: purge itr, 0x2 : purge dtr, 0x3 purge idtr.
 551  * slot: slot number to be freed.
 552  *
 553  * Must be called with preemption disabled.
 554  */
 555 void ia64_ptr_entry(u64 target_mask, int slot)
 556 {
 557         int cpu = smp_processor_id();
 558         int i;
 559         struct ia64_tr_entry *p;
 560
 561         if (slot < IA64_TR_ALLOC_BASE || slot >= per_cpu(ia64_tr_num, cpu))
 562                 return;
 563
 564         if (target_mask & 0x1) {
 565                 p = ia64_idtrs[cpu] + slot;
 566                 if ((p->pte&0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
 567                         p->pte = 0;
 568                         ia64_ptr(0x1, p->ifa, p->itir>>2);
 569                         ia64_srlz_i();
 570                 }
 571         }
 572
 573         if (target_mask & 0x2) {
 574                 p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + slot;
 575                 if ((p->pte & 0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
 576                         p->pte = 0;
 577                         ia64_ptr(0x2, p->ifa, p->itir>>2);
 578                         ia64_srlz_i();
 579                 }
 580         }
 581
 582         for (i = per_cpu(ia64_tr_used, cpu); i >= IA64_TR_ALLOC_BASE; i--) {
 583                 if (((ia64_idtrs[cpu] + i)->pte & 0x1) ||
 584                     ((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
 585                         break;
 586         }
 587         per_cpu(ia64_tr_used, cpu) = i;
 588 }
 589 EXPORT_SYMBOL_GPL(ia64_ptr_entry);