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