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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                 BUG_ON(max_purges < nptcg);
 172                 return;
 173         }
 174
 175         if (nptcg_from == NPTCG_FROM_KERNEL_PARAMETER) {
 176                 kp_override = 1;
 177                 nptcg = max_purges;
 178                 goto resetsema;
 179         }
 180         if (kp_override) {
 181                 need_ptcg_sem = num_possible_cpus() > nptcg;
 182                 return;
 183         }
 184
 185         if (nptcg_from == NPTCG_FROM_PALO) {
 186                 palo_override = 1;
 187
 188                 /* In PALO max_purges == 0 really means it! */
 189                 if (max_purges == 0)
 190                         panic("Whoa! Platform does not support global TLB purges.\n");
 191                 nptcg = max_purges;
 192                 if (nptcg == PALO_MAX_TLB_PURGES) {
 193                         need_ptcg_sem = 0;
 194                         return;
 195                 }
 196                 goto resetsema;
 197         }
 198         if (palo_override) {
 199                 if (nptcg != PALO_MAX_TLB_PURGES)
 200                         need_ptcg_sem = (num_possible_cpus() > nptcg);
 201                 return;
 202         }
 203
 204         /* In PAL_VM_SUMMARY max_purges == 0 actually means 1 */
 205         if (max_purges == 0) max_purges = 1;
 206
 207         if (firstcpu) {
 208                 nptcg = max_purges;
 209                 firstcpu = 0;
 210         }
 211         if (max_purges < nptcg)
 212                 nptcg = max_purges;
 213         if (nptcg == PAL_MAX_PURGES) {
 214                 need_ptcg_sem = 0;
 215                 return;
 216         } else
 217                 need_ptcg_sem = (num_possible_cpus() > nptcg);
 218
 219 resetsema:
 220         spinaphore_init(&ptcg_sem, max_purges);
 221 }
 222
 223 void
 224 ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
 225                        unsigned long end, unsigned long nbits)
 226 {
 227         struct mm_struct *active_mm = current->active_mm;
 228
 229         toolatetochangeptcgsem = 1;
 230
 231         if (mm != active_mm) {
 232                 /* Restore region IDs for mm */
 233                 if (mm && active_mm) {
 234                         activate_context(mm);
 235                 } else {
 236                         flush_tlb_all();
 237                         return;
 238                 }
 239         }
 240
 241         if (need_ptcg_sem)
 242                 down_spin(&ptcg_sem);
 243
 244         do {
 245                 /*
 246                  * Flush ALAT entries also.
 247                  */
 248                 ia64_ptcga(start, (nbits << 2));
 249                 ia64_srlz_i();
 250                 start += (1UL << nbits);
 251         } while (start < end);
 252
 253         if (need_ptcg_sem)
 254                 up_spin(&ptcg_sem);
 255
 256         if (mm != active_mm) {
 257                 activate_context(active_mm);
 258         }
 259 }
 260
 261 void
 262 local_flush_tlb_all (void)
 263 {
 264         unsigned long i, j, flags, count0, count1, stride0, stride1, addr;
 265
 266         addr    = local_cpu_data->ptce_base;
 267         count0  = local_cpu_data->ptce_count[0];
 268         count1  = local_cpu_data->ptce_count[1];
 269         stride0 = local_cpu_data->ptce_stride[0];
 270         stride1 = local_cpu_data->ptce_stride[1];
 271
 272         local_irq_save(flags);
 273         for (i = 0; i < count0; ++i) {
 274                 for (j = 0; j < count1; ++j) {
 275                         ia64_ptce(addr);
 276                         addr += stride1;
 277                 }
 278                 addr += stride0;
 279         }
 280         local_irq_restore(flags);
 281         ia64_srlz_i();                  /* srlz.i implies srlz.d */
 282 }
 283
 284 void
 285 flush_tlb_range (struct vm_area_struct *vma, unsigned long start,
 286                  unsigned long end)
 287 {
 288         struct mm_struct *mm = vma->vm_mm;
 289         unsigned long size = end - start;
 290         unsigned long nbits;
 291
 292 #ifndef CONFIG_SMP
 293         if (mm != current->active_mm) {
 294                 mm->context = 0;
 295                 return;
 296         }
 297 #endif
 298
 299         nbits = ia64_fls(size + 0xfff);
 300         while (unlikely (((1UL << nbits) & purge.mask) == 0) &&
 301                         (nbits < purge.max_bits))
 302                 ++nbits;
 303         if (nbits > purge.max_bits)
 304                 nbits = purge.max_bits;
 305         start &= ~((1UL << nbits) - 1);
 306
 307         preempt_disable();
 308 #ifdef CONFIG_SMP
 309         if (mm != current->active_mm || cpus_weight(mm->cpu_vm_mask) != 1) {
 310                 platform_global_tlb_purge(mm, start, end, nbits);
 311                 preempt_enable();
 312                 return;
 313         }
 314 #endif
 315         do {
 316                 ia64_ptcl(start, (nbits<<2));
 317                 start += (1UL << nbits);
 318         } while (start < end);
 319         preempt_enable();
 320         ia64_srlz_i();                  /* srlz.i implies srlz.d */
 321 }
 322 EXPORT_SYMBOL(flush_tlb_range);
 323
 324 void __devinit
 325 ia64_tlb_init (void)
 326 {
 327         ia64_ptce_info_t uninitialized_var(ptce_info); /* GCC be quiet */
 328         unsigned long tr_pgbits;
 329         long status;
 330         pal_vm_info_1_u_t vm_info_1;
 331         pal_vm_info_2_u_t vm_info_2;
 332         int cpu = smp_processor_id();
 333
 334         if ((status = ia64_pal_vm_page_size(&tr_pgbits, &purge.mask)) != 0) {
 335                 printk(KERN_ERR "PAL_VM_PAGE_SIZE failed with status=%ld; "
 336                        "defaulting to architected purge page-sizes.\n", status);
 337                 purge.mask = 0x115557000UL;
 338         }
 339         purge.max_bits = ia64_fls(purge.mask);
 340
 341         ia64_get_ptce(&ptce_info);
 342         local_cpu_data->ptce_base = ptce_info.base;
 343         local_cpu_data->ptce_count[0] = ptce_info.count[0];
 344         local_cpu_data->ptce_count[1] = ptce_info.count[1];
 345         local_cpu_data->ptce_stride[0] = ptce_info.stride[0];
 346         local_cpu_data->ptce_stride[1] = ptce_info.stride[1];
 347
 348         local_flush_tlb_all();  /* nuke left overs from bootstrapping... */
 349         status = ia64_pal_vm_summary(&vm_info_1, &vm_info_2);
 350
 351         if (status) {
 352                 printk(KERN_ERR "ia64_pal_vm_summary=%ld\n", status);
 353                 per_cpu(ia64_tr_num, cpu) = 8;
 354                 return;
 355         }
 356         per_cpu(ia64_tr_num, cpu) = vm_info_1.pal_vm_info_1_s.max_itr_entry+1;
 357         if (per_cpu(ia64_tr_num, cpu) >
 358                                 (vm_info_1.pal_vm_info_1_s.max_dtr_entry+1))
 359                 per_cpu(ia64_tr_num, cpu) =
 360                                 vm_info_1.pal_vm_info_1_s.max_dtr_entry+1;
 361         if (per_cpu(ia64_tr_num, cpu) > IA64_TR_ALLOC_MAX) {
 362                 per_cpu(ia64_tr_num, cpu) = IA64_TR_ALLOC_MAX;
 363                 printk(KERN_DEBUG "TR register number exceeds IA64_TR_ALLOC_MAX!"
 364                         "IA64_TR_ALLOC_MAX should be extended\n");
 365         }
 366 }
 367
 368 /*
 369  * is_tr_overlap
 370  *
 371  * Check overlap with inserted TRs.
 372  */
 373 static int is_tr_overlap(struct ia64_tr_entry *p, u64 va, u64 log_size)
 374 {
 375         u64 tr_log_size;
 376         u64 tr_end;
 377         u64 va_rr = ia64_get_rr(va);
 378         u64 va_rid = RR_TO_RID(va_rr);
 379         u64 va_end = va + (1<<log_size) - 1;
 380
 381         if (va_rid != RR_TO_RID(p->rr))
 382                 return 0;
 383         tr_log_size = (p->itir & 0xff) >> 2;
 384         tr_end = p->ifa + (1<<tr_log_size) - 1;
 385
 386         if (va > tr_end || p->ifa > va_end)
 387                 return 0;
 388         return 1;
 389
 390 }
 391
 392 /*
 393  * ia64_insert_tr in virtual mode. Allocate a TR slot
 394  *
 395  * target_mask : 0x1 : itr, 0x2 : dtr, 0x3 : idtr
 396  *
 397  * va   : virtual address.
 398  * pte  : pte entries inserted.
 399  * log_size: range to be covered.
 400  *
 401  * Return value:  <0 :  error No.
 402  *
 403  *                >=0 : slot number allocated for TR.
 404  * Must be called with preemption disabled.
 405  */
 406 int ia64_itr_entry(u64 target_mask, u64 va, u64 pte, u64 log_size)
 407 {
 408         int i, r;
 409         unsigned long psr;
 410         struct ia64_tr_entry *p;
 411         int cpu = smp_processor_id();
 412
 413         r = -EINVAL;
 414         /*Check overlap with existing TR entries*/
 415         if (target_mask & 0x1) {
 416                 p = &__per_cpu_idtrs[cpu][0][0];
 417                 for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
 418                                                                 i++, p++) {
 419                         if (p->pte & 0x1)
 420                                 if (is_tr_overlap(p, va, log_size)) {
 421                                         printk(KERN_DEBUG "Overlapped Entry"
 422                                                 "Inserted for TR Reigster!!\n");
 423                                         goto out;
 424                         }
 425                 }
 426         }
 427         if (target_mask & 0x2) {
 428                 p = &__per_cpu_idtrs[cpu][1][0];
 429                 for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
 430                                                                 i++, p++) {
 431                         if (p->pte & 0x1)
 432                                 if (is_tr_overlap(p, va, log_size)) {
 433                                         printk(KERN_DEBUG "Overlapped Entry"
 434                                                 "Inserted for TR Reigster!!\n");
 435                                         goto out;
 436                                 }
 437                 }
 438         }
 439
 440         for (i = IA64_TR_ALLOC_BASE; i < per_cpu(ia64_tr_num, cpu); i++) {
 441                 switch (target_mask & 0x3) {
 442                 case 1:
 443                         if (!(__per_cpu_idtrs[cpu][0][i].pte & 0x1))
 444                                 goto found;
 445                         continue;
 446                 case 2:
 447                         if (!(__per_cpu_idtrs[cpu][1][i].pte & 0x1))
 448                                 goto found;
 449                         continue;
 450                 case 3:
 451                         if (!(__per_cpu_idtrs[cpu][0][i].pte & 0x1) &&
 452                                 !(__per_cpu_idtrs[cpu][1][i].pte & 0x1))
 453                                 goto found;
 454                         continue;
 455                 default:
 456                         r = -EINVAL;
 457                         goto out;
 458                 }
 459         }
 460 found:
 461         if (i >= per_cpu(ia64_tr_num, cpu))
 462                 return -EBUSY;
 463
 464         /*Record tr info for mca hander use!*/
 465         if (i > per_cpu(ia64_tr_used, cpu))
 466                 per_cpu(ia64_tr_used, cpu) = i;
 467
 468         psr = ia64_clear_ic();
 469         if (target_mask & 0x1) {
 470                 ia64_itr(0x1, i, va, pte, log_size);
 471                 ia64_srlz_i();
 472                 p = &__per_cpu_idtrs[cpu][0][i];
 473                 p->ifa = va;
 474                 p->pte = pte;
 475                 p->itir = log_size << 2;
 476                 p->rr = ia64_get_rr(va);
 477         }
 478         if (target_mask & 0x2) {
 479                 ia64_itr(0x2, i, va, pte, log_size);
 480                 ia64_srlz_i();
 481                 p = &__per_cpu_idtrs[cpu][1][i];
 482                 p->ifa = va;
 483                 p->pte = pte;
 484                 p->itir = log_size << 2;
 485                 p->rr = ia64_get_rr(va);
 486         }
 487         ia64_set_psr(psr);
 488         r = i;
 489 out:
 490         return r;
 491 }
 492 EXPORT_SYMBOL_GPL(ia64_itr_entry);
 493
 494 /*
 495  * ia64_purge_tr
 496  *
 497  * target_mask: 0x1: purge itr, 0x2 : purge dtr, 0x3 purge idtr.
 498  * slot: slot number to be freed.
 499  *
 500  * Must be called with preemption disabled.
 501  */
 502 void ia64_ptr_entry(u64 target_mask, int slot)
 503 {
 504         int cpu = smp_processor_id();
 505         int i;
 506         struct ia64_tr_entry *p;
 507
 508         if (slot < IA64_TR_ALLOC_BASE || slot >= per_cpu(ia64_tr_num, cpu))
 509                 return;
 510
 511         if (target_mask & 0x1) {
 512                 p = &__per_cpu_idtrs[cpu][0][slot];
 513                 if ((p->pte&0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
 514                         p->pte = 0;
 515                         ia64_ptr(0x1, p->ifa, p->itir>>2);
 516                         ia64_srlz_i();
 517                 }
 518         }
 519
 520         if (target_mask & 0x2) {
 521                 p = &__per_cpu_idtrs[cpu][1][slot];
 522                 if ((p->pte & 0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
 523                         p->pte = 0;
 524                         ia64_ptr(0x2, p->ifa, p->itir>>2);
 525                         ia64_srlz_i();
 526                 }
 527         }
 528
 529         for (i = per_cpu(ia64_tr_used, cpu); i >= IA64_TR_ALLOC_BASE; i--) {
 530                 if ((__per_cpu_idtrs[cpu][0][i].pte & 0x1) ||
 531                                 (__per_cpu_idtrs[cpu][1][i].pte & 0x1))
 532                         break;
 533         }
 534         per_cpu(ia64_tr_used, cpu) = i;
 535 }
 536 EXPORT_SYMBOL_GPL(ia64_ptr_entry);