drivers/misc/cxl/irq.c

   1 /*
   2  * Copyright 2014 IBM Corp.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/interrupt.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/sched.h>
  13 #include <linux/wait.h>
  14 #include <linux/slab.h>
  15 #include <linux/pid.h>
  16 #include <asm/cputable.h>
  17 #include <misc/cxl-base.h>
  18
  19 #include "cxl.h"
  20 #include "trace.h"
  21
  22 /* XXX: This is implementation specific */
  23 static irqreturn_t handle_psl_slice_error(struct cxl_context *ctx, u64 dsisr, u64 errstat)
  24 {
  25         u64 fir1, fir2, fir_slice, serr, afu_debug;
  26
  27         fir1 = cxl_p1_read(ctx->afu->adapter, CXL_PSL_FIR1);
  28         fir2 = cxl_p1_read(ctx->afu->adapter, CXL_PSL_FIR2);
  29         fir_slice = cxl_p1n_read(ctx->afu, CXL_PSL_FIR_SLICE_An);
  30         serr = cxl_p1n_read(ctx->afu, CXL_PSL_SERR_An);
  31         afu_debug = cxl_p1n_read(ctx->afu, CXL_AFU_DEBUG_An);
  32
  33         dev_crit(&ctx->afu->dev, "PSL ERROR STATUS: 0x%016llx\n", errstat);
  34         dev_crit(&ctx->afu->dev, "PSL_FIR1: 0x%016llx\n", fir1);
  35         dev_crit(&ctx->afu->dev, "PSL_FIR2: 0x%016llx\n", fir2);
  36         dev_crit(&ctx->afu->dev, "PSL_SERR_An: 0x%016llx\n", serr);
  37         dev_crit(&ctx->afu->dev, "PSL_FIR_SLICE_An: 0x%016llx\n", fir_slice);
  38         dev_crit(&ctx->afu->dev, "CXL_PSL_AFU_DEBUG_An: 0x%016llx\n", afu_debug);
  39
  40         dev_crit(&ctx->afu->dev, "STOPPING CXL TRACE\n");
  41         cxl_stop_trace(ctx->afu->adapter);
  42
  43         return cxl_ack_irq(ctx, 0, errstat);
  44 }
  45
  46 irqreturn_t cxl_slice_irq_err(int irq, void *data)
  47 {
  48         struct cxl_afu *afu = data;
  49         u64 fir_slice, errstat, serr, afu_debug;
  50
  51         WARN(irq, "CXL SLICE ERROR interrupt %i\n", irq);
  52
  53         serr = cxl_p1n_read(afu, CXL_PSL_SERR_An);
  54         fir_slice = cxl_p1n_read(afu, CXL_PSL_FIR_SLICE_An);
  55         errstat = cxl_p2n_read(afu, CXL_PSL_ErrStat_An);
  56         afu_debug = cxl_p1n_read(afu, CXL_AFU_DEBUG_An);
  57         dev_crit(&afu->dev, "PSL_SERR_An: 0x%016llx\n", serr);
  58         dev_crit(&afu->dev, "PSL_FIR_SLICE_An: 0x%016llx\n", fir_slice);
  59         dev_crit(&afu->dev, "CXL_PSL_ErrStat_An: 0x%016llx\n", errstat);
  60         dev_crit(&afu->dev, "CXL_PSL_AFU_DEBUG_An: 0x%016llx\n", afu_debug);
  61
  62         cxl_p1n_write(afu, CXL_PSL_SERR_An, serr);
  63
  64         return IRQ_HANDLED;
  65 }
  66
  67 static irqreturn_t cxl_irq_err(int irq, void *data)
  68 {
  69         struct cxl *adapter = data;
  70         u64 fir1, fir2, err_ivte;
  71
  72         WARN(1, "CXL ERROR interrupt %i\n", irq);
  73
  74         err_ivte = cxl_p1_read(adapter, CXL_PSL_ErrIVTE);
  75         dev_crit(&adapter->dev, "PSL_ErrIVTE: 0x%016llx\n", err_ivte);
  76
  77         dev_crit(&adapter->dev, "STOPPING CXL TRACE\n");
  78         cxl_stop_trace(adapter);
  79
  80         fir1 = cxl_p1_read(adapter, CXL_PSL_FIR1);
  81         fir2 = cxl_p1_read(adapter, CXL_PSL_FIR2);
  82
  83         dev_crit(&adapter->dev, "PSL_FIR1: 0x%016llx\nPSL_FIR2: 0x%016llx\n", fir1, fir2);
  84
  85         return IRQ_HANDLED;
  86 }
  87
  88 static irqreturn_t schedule_cxl_fault(struct cxl_context *ctx, u64 dsisr, u64 dar)
  89 {
  90         ctx->dsisr = dsisr;
  91         ctx->dar = dar;
  92         schedule_work(&ctx->fault_work);
  93         return IRQ_HANDLED;
  94 }
  95
  96 static irqreturn_t cxl_irq(int irq, void *data, struct cxl_irq_info *irq_info)
  97 {
  98         struct cxl_context *ctx = data;
  99         u64 dsisr, dar;
 100
 101         dsisr = irq_info->dsisr;
 102         dar = irq_info->dar;
 103
 104         trace_cxl_psl_irq(ctx, irq, dsisr, dar);
 105
 106         pr_devel("CXL interrupt %i for afu pe: %i DSISR: %#llx DAR: %#llx\n", irq, ctx->pe, dsisr, dar);
 107
 108         if (dsisr & CXL_PSL_DSISR_An_DS) {
 109                 /*
 110                  * We don't inherently need to sleep to handle this, but we do
 111                  * need to get a ref to the task's mm, which we can't do from
 112                  * irq context without the potential for a deadlock since it
 113                  * takes the task_lock. An alternate option would be to keep a
 114                  * reference to the task's mm the entire time it has cxl open,
 115                  * but to do that we need to solve the issue where we hold a
 116                  * ref to the mm, but the mm can hold a ref to the fd after an
 117                  * mmap preventing anything from being cleaned up.
 118                  */
 119                 pr_devel("Scheduling segment miss handling for later pe: %i\n", ctx->pe);
 120                 return schedule_cxl_fault(ctx, dsisr, dar);
 121         }
 122
 123         if (dsisr & CXL_PSL_DSISR_An_M)
 124                 pr_devel("CXL interrupt: PTE not found\n");
 125         if (dsisr & CXL_PSL_DSISR_An_P)
 126                 pr_devel("CXL interrupt: Storage protection violation\n");
 127         if (dsisr & CXL_PSL_DSISR_An_A)
 128                 pr_devel("CXL interrupt: AFU lock access to write through or cache inhibited storage\n");
 129         if (dsisr & CXL_PSL_DSISR_An_S)
 130                 pr_devel("CXL interrupt: Access was afu_wr or afu_zero\n");
 131         if (dsisr & CXL_PSL_DSISR_An_K)
 132                 pr_devel("CXL interrupt: Access not permitted by virtual page class key protection\n");
 133
 134         if (dsisr & CXL_PSL_DSISR_An_DM) {
 135                 /*
 136                  * In some cases we might be able to handle the fault
 137                  * immediately if hash_page would succeed, but we still need
 138                  * the task's mm, which as above we can't get without a lock
 139                  */
 140                 pr_devel("Scheduling page fault handling for later pe: %i\n", ctx->pe);
 141                 return schedule_cxl_fault(ctx, dsisr, dar);
 142         }
 143         if (dsisr & CXL_PSL_DSISR_An_ST)
 144                 WARN(1, "CXL interrupt: Segment Table PTE not found\n");
 145         if (dsisr & CXL_PSL_DSISR_An_UR)
 146                 pr_devel("CXL interrupt: AURP PTE not found\n");
 147         if (dsisr & CXL_PSL_DSISR_An_PE)
 148                 return handle_psl_slice_error(ctx, dsisr, irq_info->errstat);
 149         if (dsisr & CXL_PSL_DSISR_An_AE) {
 150                 pr_devel("CXL interrupt: AFU Error 0x%016llx\n", irq_info->afu_err);
 151
 152                 if (ctx->pending_afu_err) {
 153                         /*
 154                          * This shouldn't happen - the PSL treats these errors
 155                          * as fatal and will have reset the AFU, so there's not
 156                          * much point buffering multiple AFU errors.
 157                          * OTOH if we DO ever see a storm of these come in it's
 158                          * probably best that we log them somewhere:
 159                          */
 160                         dev_err_ratelimited(&ctx->afu->dev, "CXL AFU Error "
 161                                             "undelivered to pe %i: 0x%016llx\n",
 162                                             ctx->pe, irq_info->afu_err);
 163                 } else {
 164                         spin_lock(&ctx->lock);
 165                         ctx->afu_err = irq_info->afu_err;
 166                         ctx->pending_afu_err = 1;
 167                         spin_unlock(&ctx->lock);
 168
 169                         wake_up_all(&ctx->wq);
 170                 }
 171
 172                 cxl_ack_irq(ctx, CXL_PSL_TFC_An_A, 0);
 173                 return IRQ_HANDLED;
 174         }
 175         if (dsisr & CXL_PSL_DSISR_An_OC)
 176                 pr_devel("CXL interrupt: OS Context Warning\n");
 177
 178         WARN(1, "Unhandled CXL PSL IRQ\n");
 179         return IRQ_HANDLED;
 180 }
 181
 182 static irqreturn_t fail_psl_irq(struct cxl_afu *afu, struct cxl_irq_info *irq_info)
 183 {
 184         if (irq_info->dsisr & CXL_PSL_DSISR_TRANS)
 185                 cxl_p2n_write(afu, CXL_PSL_TFC_An, CXL_PSL_TFC_An_AE);
 186         else
 187                 cxl_p2n_write(afu, CXL_PSL_TFC_An, CXL_PSL_TFC_An_A);
 188
 189         return IRQ_HANDLED;
 190 }
 191
 192 static irqreturn_t cxl_irq_multiplexed(int irq, void *data)
 193 {
 194         struct cxl_afu *afu = data;
 195         struct cxl_context *ctx;
 196         struct cxl_irq_info irq_info;
 197         int ph = cxl_p2n_read(afu, CXL_PSL_PEHandle_An) & 0xffff;
 198         int ret;
 199
 200         if ((ret = cxl_get_irq(afu, &irq_info))) {
 201                 WARN(1, "Unable to get CXL IRQ Info: %i\n", ret);
 202                 return fail_psl_irq(afu, &irq_info);
 203         }
 204
 205         rcu_read_lock();
 206         ctx = idr_find(&afu->contexts_idr, ph);
 207         if (ctx) {
 208                 ret = cxl_irq(irq, ctx, &irq_info);
 209                 rcu_read_unlock();
 210                 return ret;
 211         }
 212         rcu_read_unlock();
 213
 214         WARN(1, "Unable to demultiplex CXL PSL IRQ for PE %i DSISR %016llx DAR"
 215                 " %016llx\n(Possible AFU HW issue - was a term/remove acked"
 216                 " with outstanding transactions?)\n", ph, irq_info.dsisr,
 217                 irq_info.dar);
 218         return fail_psl_irq(afu, &irq_info);
 219 }
 220
 221 static irqreturn_t cxl_irq_afu(int irq, void *data)
 222 {
 223         struct cxl_context *ctx = data;
 224         irq_hw_number_t hwirq = irqd_to_hwirq(irq_get_irq_data(irq));
 225         int irq_off, afu_irq = 1;
 226         __u16 range;
 227         int r;
 228
 229         for (r = 1; r < CXL_IRQ_RANGES; r++) {
 230                 irq_off = hwirq - ctx->irqs.offset[r];
 231                 range = ctx->irqs.range[r];
 232                 if (irq_off >= 0 && irq_off < range) {
 233                         afu_irq += irq_off;
 234                         break;
 235                 }
 236                 afu_irq += range;
 237         }
 238         if (unlikely(r >= CXL_IRQ_RANGES)) {
 239                 WARN(1, "Recieved AFU IRQ out of range for pe %i (virq %i hwirq %lx)\n",
 240                      ctx->pe, irq, hwirq);
 241                 return IRQ_HANDLED;
 242         }
 243
 244         trace_cxl_afu_irq(ctx, afu_irq, irq, hwirq);
 245         pr_devel("Received AFU interrupt %i for pe: %i (virq %i hwirq %lx)\n",
 246                afu_irq, ctx->pe, irq, hwirq);
 247
 248         if (unlikely(!ctx->irq_bitmap)) {
 249                 WARN(1, "Recieved AFU IRQ for context with no IRQ bitmap\n");
 250                 return IRQ_HANDLED;
 251         }
 252         spin_lock(&ctx->lock);
 253         set_bit(afu_irq - 1, ctx->irq_bitmap);
 254         ctx->pending_irq = true;
 255         spin_unlock(&ctx->lock);
 256
 257         wake_up_all(&ctx->wq);
 258
 259         return IRQ_HANDLED;
 260 }
 261
 262 unsigned int cxl_map_irq(struct cxl *adapter, irq_hw_number_t hwirq,
 263                          irq_handler_t handler, void *cookie, const char *name)
 264 {
 265         unsigned int virq;
 266         int result;
 267
 268         /* IRQ Domain? */
 269         virq = irq_create_mapping(NULL, hwirq);
 270         if (!virq) {
 271                 dev_warn(&adapter->dev, "cxl_map_irq: irq_create_mapping failed\n");
 272                 return 0;
 273         }
 274
 275         cxl_setup_irq(adapter, hwirq, virq);
 276
 277         pr_devel("hwirq %#lx mapped to virq %u\n", hwirq, virq);
 278
 279         result = request_irq(virq, handler, 0, name, cookie);
 280         if (result) {
 281                 dev_warn(&adapter->dev, "cxl_map_irq: request_irq failed: %i\n", result);
 282                 return 0;
 283         }
 284
 285         return virq;
 286 }
 287
 288 void cxl_unmap_irq(unsigned int virq, void *cookie)
 289 {
 290         free_irq(virq, cookie);
 291         irq_dispose_mapping(virq);
 292 }
 293
 294 static int cxl_register_one_irq(struct cxl *adapter,
 295                                 irq_handler_t handler,
 296                                 void *cookie,
 297                                 irq_hw_number_t *dest_hwirq,
 298                                 unsigned int *dest_virq,
 299                                 const char *name)
 300 {
 301         int hwirq, virq;
 302
 303         if ((hwirq = cxl_alloc_one_irq(adapter)) < 0)
 304                 return hwirq;
 305
 306         if (!(virq = cxl_map_irq(adapter, hwirq, handler, cookie, name)))
 307                 goto err;
 308
 309         *dest_hwirq = hwirq;
 310         *dest_virq = virq;
 311
 312         return 0;
 313
 314 err:
 315         cxl_release_one_irq(adapter, hwirq);
 316         return -ENOMEM;
 317 }
 318
 319 int cxl_register_psl_err_irq(struct cxl *adapter)
 320 {
 321         int rc;
 322
 323         adapter->irq_name = kasprintf(GFP_KERNEL, "cxl-%s-err",
 324                                       dev_name(&adapter->dev));
 325         if (!adapter->irq_name)
 326                 return -ENOMEM;
 327
 328         if ((rc = cxl_register_one_irq(adapter, cxl_irq_err, adapter,
 329                                        &adapter->err_hwirq,
 330                                        &adapter->err_virq,
 331                                        adapter->irq_name))) {
 332                 kfree(adapter->irq_name);
 333                 adapter->irq_name = NULL;
 334                 return rc;
 335         }
 336
 337         cxl_p1_write(adapter, CXL_PSL_ErrIVTE, adapter->err_hwirq & 0xffff);
 338
 339         return 0;
 340 }
 341
 342 void cxl_release_psl_err_irq(struct cxl *adapter)
 343 {
 344         if (adapter->err_virq != irq_find_mapping(NULL, adapter->err_hwirq))
 345                 return;
 346
 347         cxl_p1_write(adapter, CXL_PSL_ErrIVTE, 0x0000000000000000);
 348         cxl_unmap_irq(adapter->err_virq, adapter);
 349         cxl_release_one_irq(adapter, adapter->err_hwirq);
 350         kfree(adapter->irq_name);
 351 }
 352
 353 int cxl_register_serr_irq(struct cxl_afu *afu)
 354 {
 355         u64 serr;
 356         int rc;
 357
 358         afu->err_irq_name = kasprintf(GFP_KERNEL, "cxl-%s-err",
 359                                       dev_name(&afu->dev));
 360         if (!afu->err_irq_name)
 361                 return -ENOMEM;
 362
 363         if ((rc = cxl_register_one_irq(afu->adapter, cxl_slice_irq_err, afu,
 364                                        &afu->serr_hwirq,
 365                                        &afu->serr_virq, afu->err_irq_name))) {
 366                 kfree(afu->err_irq_name);
 367                 afu->err_irq_name = NULL;
 368                 return rc;
 369         }
 370
 371         serr = cxl_p1n_read(afu, CXL_PSL_SERR_An);
 372         serr = (serr & 0x00ffffffffff0000ULL) | (afu->serr_hwirq & 0xffff);
 373         cxl_p1n_write(afu, CXL_PSL_SERR_An, serr);
 374
 375         return 0;
 376 }
 377
 378 void cxl_release_serr_irq(struct cxl_afu *afu)
 379 {
 380         if (afu->serr_virq != irq_find_mapping(NULL, afu->serr_hwirq))
 381                 return;
 382
 383         cxl_p1n_write(afu, CXL_PSL_SERR_An, 0x0000000000000000);
 384         cxl_unmap_irq(afu->serr_virq, afu);
 385         cxl_release_one_irq(afu->adapter, afu->serr_hwirq);
 386         kfree(afu->err_irq_name);
 387 }
 388
 389 int cxl_register_psl_irq(struct cxl_afu *afu)
 390 {
 391         int rc;
 392
 393         afu->psl_irq_name = kasprintf(GFP_KERNEL, "cxl-%s",
 394                                       dev_name(&afu->dev));
 395         if (!afu->psl_irq_name)
 396                 return -ENOMEM;
 397
 398         if ((rc = cxl_register_one_irq(afu->adapter, cxl_irq_multiplexed, afu,
 399                                     &afu->psl_hwirq, &afu->psl_virq,
 400                                     afu->psl_irq_name))) {
 401                 kfree(afu->psl_irq_name);
 402                 afu->psl_irq_name = NULL;
 403         }
 404         return rc;
 405 }
 406
 407 void cxl_release_psl_irq(struct cxl_afu *afu)
 408 {
 409         if (afu->psl_virq != irq_find_mapping(NULL, afu->psl_hwirq))
 410                 return;
 411
 412         cxl_unmap_irq(afu->psl_virq, afu);
 413         cxl_release_one_irq(afu->adapter, afu->psl_hwirq);
 414         kfree(afu->psl_irq_name);
 415 }
 416
 417 void afu_irq_name_free(struct cxl_context *ctx)
 418 {
 419         struct cxl_irq_name *irq_name, *tmp;
 420
 421         list_for_each_entry_safe(irq_name, tmp, &ctx->irq_names, list) {
 422                 kfree(irq_name->name);
 423                 list_del(&irq_name->list);
 424                 kfree(irq_name);
 425         }
 426 }
 427
 428 int afu_allocate_irqs(struct cxl_context *ctx, u32 count)
 429 {
 430         int rc, r, i, j = 1;
 431         struct cxl_irq_name *irq_name;
 432
 433         /* Initialize the list head to hold irq names */
 434         INIT_LIST_HEAD(&ctx->irq_names);
 435
 436         if ((rc = cxl_alloc_irq_ranges(&ctx->irqs, ctx->afu->adapter, count)))
 437                 return rc;
 438
 439         /* Multiplexed PSL Interrupt */
 440         ctx->irqs.offset[0] = ctx->afu->psl_hwirq;
 441         ctx->irqs.range[0] = 1;
 442
 443         ctx->irq_count = count;
 444         ctx->irq_bitmap = kcalloc(BITS_TO_LONGS(count),
 445                                   sizeof(*ctx->irq_bitmap), GFP_KERNEL);
 446         if (!ctx->irq_bitmap)
 447                 goto out;
 448
 449         /*
 450          * Allocate names first.  If any fail, bail out before allocating
 451          * actual hardware IRQs.
 452          */
 453         for (r = 1; r < CXL_IRQ_RANGES; r++) {
 454                 for (i = 0; i < ctx->irqs.range[r]; i++) {
 455                         irq_name = kmalloc(sizeof(struct cxl_irq_name),
 456                                            GFP_KERNEL);
 457                         if (!irq_name)
 458                                 goto out;
 459                         irq_name->name = kasprintf(GFP_KERNEL, "cxl-%s-pe%i-%i",
 460                                                    dev_name(&ctx->afu->dev),
 461                                                    ctx->pe, j);
 462                         if (!irq_name->name) {
 463                                 kfree(irq_name);
 464                                 goto out;
 465                         }
 466                         /* Add to tail so next look get the correct order */
 467                         list_add_tail(&irq_name->list, &ctx->irq_names);
 468                         j++;
 469                 }
 470         }
 471         return 0;
 472
 473 out:
 474         cxl_release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
 475         afu_irq_name_free(ctx);
 476         return -ENOMEM;
 477 }
 478
 479 static void afu_register_hwirqs(struct cxl_context *ctx)
 480 {
 481         irq_hw_number_t hwirq;
 482         struct cxl_irq_name *irq_name;
 483         int r,i;
 484
 485         /* We've allocated all memory now, so let's do the irq allocations */
 486         irq_name = list_first_entry(&ctx->irq_names, struct cxl_irq_name, list);
 487         for (r = 1; r < CXL_IRQ_RANGES; r++) {
 488                 hwirq = ctx->irqs.offset[r];
 489                 for (i = 0; i < ctx->irqs.range[r]; hwirq++, i++) {
 490                         cxl_map_irq(ctx->afu->adapter, hwirq,
 491                                     cxl_irq_afu, ctx, irq_name->name);
 492                         irq_name = list_next_entry(irq_name, list);
 493                 }
 494         }
 495 }
 496
 497 int afu_register_irqs(struct cxl_context *ctx, u32 count)
 498 {
 499         int rc;
 500
 501         rc = afu_allocate_irqs(ctx, count);
 502         if (rc)
 503                 return rc;
 504
 505         afu_register_hwirqs(ctx);
 506         return 0;
 507  }
 508
 509 void afu_release_irqs(struct cxl_context *ctx, void *cookie)
 510 {
 511         irq_hw_number_t hwirq;
 512         unsigned int virq;
 513         int r, i;
 514
 515         for (r = 1; r < CXL_IRQ_RANGES; r++) {
 516                 hwirq = ctx->irqs.offset[r];
 517                 for (i = 0; i < ctx->irqs.range[r]; hwirq++, i++) {
 518                         virq = irq_find_mapping(NULL, hwirq);
 519                         if (virq)
 520                                 cxl_unmap_irq(virq, cookie);
 521                 }
 522         }
 523
 524         afu_irq_name_free(ctx);
 525         cxl_release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
 526
 527         ctx->irq_count = 0;
 528 }