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