linux/drivers/misc/sgi-gru/grukservices.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * SN Platform GRU Driver
   4 *
   5 *              KERNEL SERVICES THAT USE THE GRU
   6 *
   7 *  Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/errno.h>
  12#include <linux/slab.h>
  13#include <linux/mm.h>
  14#include <linux/spinlock.h>
  15#include <linux/device.h>
  16#include <linux/miscdevice.h>
  17#include <linux/proc_fs.h>
  18#include <linux/interrupt.h>
  19#include <linux/sync_core.h>
  20#include <linux/uaccess.h>
  21#include <linux/delay.h>
  22#include <linux/export.h>
  23#include <asm/io_apic.h>
  24#include "gru.h"
  25#include "grulib.h"
  26#include "grutables.h"
  27#include "grukservices.h"
  28#include "gru_instructions.h"
  29#include <asm/uv/uv_hub.h>
  30
  31/*
  32 * Kernel GRU Usage
  33 *
  34 * The following is an interim algorithm for management of kernel GRU
  35 * resources. This will likely be replaced when we better understand the
  36 * kernel/user requirements.
  37 *
  38 * Blade percpu resources reserved for kernel use. These resources are
  39 * reserved whenever the the kernel context for the blade is loaded. Note
  40 * that the kernel context is not guaranteed to be always available. It is
  41 * loaded on demand & can be stolen by a user if the user demand exceeds the
  42 * kernel demand. The kernel can always reload the kernel context but
  43 * a SLEEP may be required!!!.
  44 *
  45 * Async Overview:
  46 *
  47 *      Each blade has one "kernel context" that owns GRU kernel resources
  48 *      located on the blade. Kernel drivers use GRU resources in this context
  49 *      for sending messages, zeroing memory, etc.
  50 *
  51 *      The kernel context is dynamically loaded on demand. If it is not in
  52 *      use by the kernel, the kernel context can be unloaded & given to a user.
  53 *      The kernel context will be reloaded when needed. This may require that
  54 *      a context be stolen from a user.
  55 *              NOTE: frequent unloading/reloading of the kernel context is
  56 *              expensive. We are depending on batch schedulers, cpusets, sane
  57 *              drivers or some other mechanism to prevent the need for frequent
  58 *              stealing/reloading.
  59 *
  60 *      The kernel context consists of two parts:
  61 *              - 1 CB & a few DSRs that are reserved for each cpu on the blade.
  62 *                Each cpu has it's own private resources & does not share them
  63 *                with other cpus. These resources are used serially, ie,
  64 *                locked, used & unlocked  on each call to a function in
  65 *                grukservices.
  66 *                      (Now that we have dynamic loading of kernel contexts, I
  67 *                       may rethink this & allow sharing between cpus....)
  68 *
  69 *              - Additional resources can be reserved long term & used directly
  70 *                by UV drivers located in the kernel. Drivers using these GRU
  71 *                resources can use asynchronous GRU instructions that send
  72 *                interrupts on completion.
  73 *                      - these resources must be explicitly locked/unlocked
  74 *                      - locked resources prevent (obviously) the kernel
  75 *                        context from being unloaded.
  76 *                      - drivers using these resource directly issue their own
  77 *                        GRU instruction and must wait/check completion.
  78 *
  79 *                When these resources are reserved, the caller can optionally
  80 *                associate a wait_queue with the resources and use asynchronous
  81 *                GRU instructions. When an async GRU instruction completes, the
  82 *                driver will do a wakeup on the event.
  83 *
  84 */
  85
  86
  87#define ASYNC_HAN_TO_BID(h)     ((h) - 1)
  88#define ASYNC_BID_TO_HAN(b)     ((b) + 1)
  89#define ASYNC_HAN_TO_BS(h)      gru_base[ASYNC_HAN_TO_BID(h)]
  90
  91#define GRU_NUM_KERNEL_CBR      1
  92#define GRU_NUM_KERNEL_DSR_BYTES 256
  93#define GRU_NUM_KERNEL_DSR_CL   (GRU_NUM_KERNEL_DSR_BYTES /             \
  94                                        GRU_CACHE_LINE_BYTES)
  95
  96/* GRU instruction attributes for all instructions */
  97#define IMA                     IMA_CB_DELAY
  98
  99/* GRU cacheline size is always 64 bytes - even on arches with 128 byte lines */
 100#define __gru_cacheline_aligned__                               \
 101        __attribute__((__aligned__(GRU_CACHE_LINE_BYTES)))
 102
 103#define MAGIC   0x1234567887654321UL
 104
 105/* Default retry count for GRU errors on kernel instructions */
 106#define EXCEPTION_RETRY_LIMIT   3
 107
 108/* Status of message queue sections */
 109#define MQS_EMPTY               0
 110#define MQS_FULL                1
 111#define MQS_NOOP                2
 112
 113/*----------------- RESOURCE MANAGEMENT -------------------------------------*/
 114/* optimized for x86_64 */
 115struct message_queue {
 116        union gru_mesqhead      head __gru_cacheline_aligned__; /* CL 0 */
 117        int                     qlines;                         /* DW 1 */
 118        long                    hstatus[2];
 119        void                    *next __gru_cacheline_aligned__;/* CL 1 */
 120        void                    *limit;
 121        void                    *start;
 122        void                    *start2;
 123        char                    data ____cacheline_aligned;     /* CL 2 */
 124};
 125
 126/* First word in every message - used by mesq interface */
 127struct message_header {
 128        char    present;
 129        char    present2;
 130        char    lines;
 131        char    fill;
 132};
 133
 134#define HSTATUS(mq, h)  ((mq) + offsetof(struct message_queue, hstatus[h]))
 135
 136/*
 137 * Reload the blade's kernel context into a GRU chiplet. Called holding
 138 * the bs_kgts_sema for READ. Will steal user contexts if necessary.
 139 */
 140static void gru_load_kernel_context(struct gru_blade_state *bs, int blade_id)
 141{
 142        struct gru_state *gru;
 143        struct gru_thread_state *kgts;
 144        void *vaddr;
 145        int ctxnum, ncpus;
 146
 147        up_read(&bs->bs_kgts_sema);
 148        down_write(&bs->bs_kgts_sema);
 149
 150        if (!bs->bs_kgts) {
 151                do {
 152                        bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0, 0);
 153                        if (!IS_ERR(bs->bs_kgts))
 154                                break;
 155                        msleep(1);
 156                } while (true);
 157                bs->bs_kgts->ts_user_blade_id = blade_id;
 158        }
 159        kgts = bs->bs_kgts;
 160
 161        if (!kgts->ts_gru) {
 162                STAT(load_kernel_context);
 163                ncpus = uv_blade_nr_possible_cpus(blade_id);
 164                kgts->ts_cbr_au_count = GRU_CB_COUNT_TO_AU(
 165                        GRU_NUM_KERNEL_CBR * ncpus + bs->bs_async_cbrs);
 166                kgts->ts_dsr_au_count = GRU_DS_BYTES_TO_AU(
 167                        GRU_NUM_KERNEL_DSR_BYTES * ncpus +
 168                                bs->bs_async_dsr_bytes);
 169                while (!gru_assign_gru_context(kgts)) {
 170                        msleep(1);
 171                        gru_steal_context(kgts);
 172                }
 173                gru_load_context(kgts);
 174                gru = bs->bs_kgts->ts_gru;
 175                vaddr = gru->gs_gru_base_vaddr;
 176                ctxnum = kgts->ts_ctxnum;
 177                bs->kernel_cb = get_gseg_base_address_cb(vaddr, ctxnum, 0);
 178                bs->kernel_dsr = get_gseg_base_address_ds(vaddr, ctxnum, 0);
 179        }
 180        downgrade_write(&bs->bs_kgts_sema);
 181}
 182
 183/*
 184 * Free all kernel contexts that are not currently in use.
 185 *   Returns 0 if all freed, else number of inuse context.
 186 */
 187static int gru_free_kernel_contexts(void)
 188{
 189        struct gru_blade_state *bs;
 190        struct gru_thread_state *kgts;
 191        int bid, ret = 0;
 192
 193        for (bid = 0; bid < GRU_MAX_BLADES; bid++) {
 194                bs = gru_base[bid];
 195                if (!bs)
 196                        continue;
 197
 198                /* Ignore busy contexts. Don't want to block here.  */
 199                if (down_write_trylock(&bs->bs_kgts_sema)) {
 200                        kgts = bs->bs_kgts;
 201                        if (kgts && kgts->ts_gru)
 202                                gru_unload_context(kgts, 0);
 203                        bs->bs_kgts = NULL;
 204                        up_write(&bs->bs_kgts_sema);
 205                        kfree(kgts);
 206                } else {
 207                        ret++;
 208                }
 209        }
 210        return ret;
 211}
 212
 213/*
 214 * Lock & load the kernel context for the specified blade.
 215 */
 216static struct gru_blade_state *gru_lock_kernel_context(int blade_id)
 217{
 218        struct gru_blade_state *bs;
 219        int bid;
 220
 221        STAT(lock_kernel_context);
 222again:
 223        bid = blade_id < 0 ? uv_numa_blade_id() : blade_id;
 224        bs = gru_base[bid];
 225
 226        /* Handle the case where migration occurred while waiting for the sema */
 227        down_read(&bs->bs_kgts_sema);
 228        if (blade_id < 0 && bid != uv_numa_blade_id()) {
 229                up_read(&bs->bs_kgts_sema);
 230                goto again;
 231        }
 232        if (!bs->bs_kgts || !bs->bs_kgts->ts_gru)
 233                gru_load_kernel_context(bs, bid);
 234        return bs;
 235
 236}
 237
 238/*
 239 * Unlock the kernel context for the specified blade. Context is not
 240 * unloaded but may be stolen before next use.
 241 */
 242static void gru_unlock_kernel_context(int blade_id)
 243{
 244        struct gru_blade_state *bs;
 245
 246        bs = gru_base[blade_id];
 247        up_read(&bs->bs_kgts_sema);
 248        STAT(unlock_kernel_context);
 249}
 250
 251/*
 252 * Reserve & get pointers to the DSR/CBRs reserved for the current cpu.
 253 *      - returns with preemption disabled
 254 */
 255static int gru_get_cpu_resources(int dsr_bytes, void **cb, void **dsr)
 256{
 257        struct gru_blade_state *bs;
 258        int lcpu;
 259
 260        BUG_ON(dsr_bytes > GRU_NUM_KERNEL_DSR_BYTES);
 261        preempt_disable();
 262        bs = gru_lock_kernel_context(-1);
 263        lcpu = uv_blade_processor_id();
 264        *cb = bs->kernel_cb + lcpu * GRU_HANDLE_STRIDE;
 265        *dsr = bs->kernel_dsr + lcpu * GRU_NUM_KERNEL_DSR_BYTES;
 266        return 0;
 267}
 268
 269/*
 270 * Free the current cpus reserved DSR/CBR resources.
 271 */
 272static void gru_free_cpu_resources(void *cb, void *dsr)
 273{
 274        gru_unlock_kernel_context(uv_numa_blade_id());
 275        preempt_enable();
 276}
 277
 278/*
 279 * Reserve GRU resources to be used asynchronously.
 280 *   Note: currently supports only 1 reservation per blade.
 281 *
 282 *      input:
 283 *              blade_id  - blade on which resources should be reserved
 284 *              cbrs      - number of CBRs
 285 *              dsr_bytes - number of DSR bytes needed
 286 *      output:
 287 *              handle to identify resource
 288 *              (0 = async resources already reserved)
 289 */
 290unsigned long gru_reserve_async_resources(int blade_id, int cbrs, int dsr_bytes,
 291                        struct completion *cmp)
 292{
 293        struct gru_blade_state *bs;
 294        struct gru_thread_state *kgts;
 295        int ret = 0;
 296
 297        bs = gru_base[blade_id];
 298
 299        down_write(&bs->bs_kgts_sema);
 300
 301        /* Verify no resources already reserved */
 302        if (bs->bs_async_dsr_bytes + bs->bs_async_cbrs)
 303                goto done;
 304        bs->bs_async_dsr_bytes = dsr_bytes;
 305        bs->bs_async_cbrs = cbrs;
 306        bs->bs_async_wq = cmp;
 307        kgts = bs->bs_kgts;
 308
 309        /* Resources changed. Unload context if already loaded */
 310        if (kgts && kgts->ts_gru)
 311                gru_unload_context(kgts, 0);
 312        ret = ASYNC_BID_TO_HAN(blade_id);
 313
 314done:
 315        up_write(&bs->bs_kgts_sema);
 316        return ret;
 317}
 318
 319/*
 320 * Release async resources previously reserved.
 321 *
 322 *      input:
 323 *              han - handle to identify resources
 324 */
 325void gru_release_async_resources(unsigned long han)
 326{
 327        struct gru_blade_state *bs = ASYNC_HAN_TO_BS(han);
 328
 329        down_write(&bs->bs_kgts_sema);
 330        bs->bs_async_dsr_bytes = 0;
 331        bs->bs_async_cbrs = 0;
 332        bs->bs_async_wq = NULL;
 333        up_write(&bs->bs_kgts_sema);
 334}
 335
 336/*
 337 * Wait for async GRU instructions to complete.
 338 *
 339 *      input:
 340 *              han - handle to identify resources
 341 */
 342void gru_wait_async_cbr(unsigned long han)
 343{
 344        struct gru_blade_state *bs = ASYNC_HAN_TO_BS(han);
 345
 346        wait_for_completion(bs->bs_async_wq);
 347        mb();
 348}
 349
 350/*
 351 * Lock previous reserved async GRU resources
 352 *
 353 *      input:
 354 *              han - handle to identify resources
 355 *      output:
 356 *              cb  - pointer to first CBR
 357 *              dsr - pointer to first DSR
 358 */
 359void gru_lock_async_resource(unsigned long han,  void **cb, void **dsr)
 360{
 361        struct gru_blade_state *bs = ASYNC_HAN_TO_BS(han);
 362        int blade_id = ASYNC_HAN_TO_BID(han);
 363        int ncpus;
 364
 365        gru_lock_kernel_context(blade_id);
 366        ncpus = uv_blade_nr_possible_cpus(blade_id);
 367        if (cb)
 368                *cb = bs->kernel_cb + ncpus * GRU_HANDLE_STRIDE;
 369        if (dsr)
 370                *dsr = bs->kernel_dsr + ncpus * GRU_NUM_KERNEL_DSR_BYTES;
 371}
 372
 373/*
 374 * Unlock previous reserved async GRU resources
 375 *
 376 *      input:
 377 *              han - handle to identify resources
 378 */
 379void gru_unlock_async_resource(unsigned long han)
 380{
 381        int blade_id = ASYNC_HAN_TO_BID(han);
 382
 383        gru_unlock_kernel_context(blade_id);
 384}
 385
 386/*----------------------------------------------------------------------*/
 387int gru_get_cb_exception_detail(void *cb,
 388                struct control_block_extended_exc_detail *excdet)
 389{
 390        struct gru_control_block_extended *cbe;
 391        struct gru_thread_state *kgts = NULL;
 392        unsigned long off;
 393        int cbrnum, bid;
 394
 395        /*
 396         * Locate kgts for cb. This algorithm is SLOW but
 397         * this function is rarely called (ie., almost never).
 398         * Performance does not matter.
 399         */
 400        for_each_possible_blade(bid) {
 401                if (!gru_base[bid])
 402                        break;
 403                kgts = gru_base[bid]->bs_kgts;
 404                if (!kgts || !kgts->ts_gru)
 405                        continue;
 406                off = cb - kgts->ts_gru->gs_gru_base_vaddr;
 407                if (off < GRU_SIZE)
 408                        break;
 409                kgts = NULL;
 410        }
 411        BUG_ON(!kgts);
 412        cbrnum = thread_cbr_number(kgts, get_cb_number(cb));
 413        cbe = get_cbe(GRUBASE(cb), cbrnum);
 414        gru_flush_cache(cbe);   /* CBE not coherent */
 415        sync_core();
 416        excdet->opc = cbe->opccpy;
 417        excdet->exopc = cbe->exopccpy;
 418        excdet->ecause = cbe->ecause;
 419        excdet->exceptdet0 = cbe->idef1upd;
 420        excdet->exceptdet1 = cbe->idef3upd;
 421        gru_flush_cache(cbe);
 422        return 0;
 423}
 424
 425static char *gru_get_cb_exception_detail_str(int ret, void *cb,
 426                                             char *buf, int size)
 427{
 428        struct gru_control_block_status *gen = (void *)cb;
 429        struct control_block_extended_exc_detail excdet;
 430
 431        if (ret > 0 && gen->istatus == CBS_EXCEPTION) {
 432                gru_get_cb_exception_detail(cb, &excdet);
 433                snprintf(buf, size,
 434                        "GRU:%d exception: cb %p, opc %d, exopc %d, ecause 0x%x,"
 435                        "excdet0 0x%lx, excdet1 0x%x", smp_processor_id(),
 436                        gen, excdet.opc, excdet.exopc, excdet.ecause,
 437                        excdet.exceptdet0, excdet.exceptdet1);
 438        } else {
 439                snprintf(buf, size, "No exception");
 440        }
 441        return buf;
 442}
 443
 444static int gru_wait_idle_or_exception(struct gru_control_block_status *gen)
 445{
 446        while (gen->istatus >= CBS_ACTIVE) {
 447                cpu_relax();
 448                barrier();
 449        }
 450        return gen->istatus;
 451}
 452
 453static int gru_retry_exception(void *cb)
 454{
 455        struct gru_control_block_status *gen = (void *)cb;
 456        struct control_block_extended_exc_detail excdet;
 457        int retry = EXCEPTION_RETRY_LIMIT;
 458
 459        while (1)  {
 460                if (gru_wait_idle_or_exception(gen) == CBS_IDLE)
 461                        return CBS_IDLE;
 462                if (gru_get_cb_message_queue_substatus(cb))
 463                        return CBS_EXCEPTION;
 464                gru_get_cb_exception_detail(cb, &excdet);
 465                if ((excdet.ecause & ~EXCEPTION_RETRY_BITS) ||
 466                                (excdet.cbrexecstatus & CBR_EXS_ABORT_OCC))
 467                        break;
 468                if (retry-- == 0)
 469                        break;
 470                gen->icmd = 1;
 471                gru_flush_cache(gen);
 472        }
 473        return CBS_EXCEPTION;
 474}
 475
 476int gru_check_status_proc(void *cb)
 477{
 478        struct gru_control_block_status *gen = (void *)cb;
 479        int ret;
 480
 481        ret = gen->istatus;
 482        if (ret == CBS_EXCEPTION)
 483                ret = gru_retry_exception(cb);
 484        rmb();
 485        return ret;
 486
 487}
 488
 489int gru_wait_proc(void *cb)
 490{
 491        struct gru_control_block_status *gen = (void *)cb;
 492        int ret;
 493
 494        ret = gru_wait_idle_or_exception(gen);
 495        if (ret == CBS_EXCEPTION)
 496                ret = gru_retry_exception(cb);
 497        rmb();
 498        return ret;
 499}
 500
 501static void gru_abort(int ret, void *cb, char *str)
 502{
 503        char buf[GRU_EXC_STR_SIZE];
 504
 505        panic("GRU FATAL ERROR: %s - %s\n", str,
 506              gru_get_cb_exception_detail_str(ret, cb, buf, sizeof(buf)));
 507}
 508
 509void gru_wait_abort_proc(void *cb)
 510{
 511        int ret;
 512
 513        ret = gru_wait_proc(cb);
 514        if (ret)
 515                gru_abort(ret, cb, "gru_wait_abort");
 516}
 517
 518
 519/*------------------------------ MESSAGE QUEUES -----------------------------*/
 520
 521/* Internal status . These are NOT returned to the user. */
 522#define MQIE_AGAIN              -1      /* try again */
 523
 524
 525/*
 526 * Save/restore the "present" flag that is in the second line of 2-line
 527 * messages
 528 */
 529static inline int get_present2(void *p)
 530{
 531        struct message_header *mhdr = p + GRU_CACHE_LINE_BYTES;
 532        return mhdr->present;
 533}
 534
 535static inline void restore_present2(void *p, int val)
 536{
 537        struct message_header *mhdr = p + GRU_CACHE_LINE_BYTES;
 538        mhdr->present = val;
 539}
 540
 541/*
 542 * Create a message queue.
 543 *      qlines - message queue size in cache lines. Includes 2-line header.
 544 */
 545int gru_create_message_queue(struct gru_message_queue_desc *mqd,
 546                void *p, unsigned int bytes, int nasid, int vector, int apicid)
 547{
 548        struct message_queue *mq = p;
 549        unsigned int qlines;
 550
 551        qlines = bytes / GRU_CACHE_LINE_BYTES - 2;
 552        memset(mq, 0, bytes);
 553        mq->start = &mq->data;
 554        mq->start2 = &mq->data + (qlines / 2 - 1) * GRU_CACHE_LINE_BYTES;
 555        mq->next = &mq->data;
 556        mq->limit = &mq->data + (qlines - 2) * GRU_CACHE_LINE_BYTES;
 557        mq->qlines = qlines;
 558        mq->hstatus[0] = 0;
 559        mq->hstatus[1] = 1;
 560        mq->head = gru_mesq_head(2, qlines / 2 + 1);
 561        mqd->mq = mq;
 562        mqd->mq_gpa = uv_gpa(mq);
 563        mqd->qlines = qlines;
 564        mqd->interrupt_pnode = nasid >> 1;
 565        mqd->interrupt_vector = vector;
 566        mqd->interrupt_apicid = apicid;
 567        return 0;
 568}
 569EXPORT_SYMBOL_GPL(gru_create_message_queue);
 570
 571/*
 572 * Send a NOOP message to a message queue
 573 *      Returns:
 574 *               0 - if queue is full after the send. This is the normal case
 575 *                   but various races can change this.
 576 *              -1 - if mesq sent successfully but queue not full
 577 *              >0 - unexpected error. MQE_xxx returned
 578 */
 579static int send_noop_message(void *cb, struct gru_message_queue_desc *mqd,
 580                                void *mesg)
 581{
 582        const struct message_header noop_header = {
 583                                        .present = MQS_NOOP, .lines = 1};
 584        unsigned long m;
 585        int substatus, ret;
 586        struct message_header save_mhdr, *mhdr = mesg;
 587
 588        STAT(mesq_noop);
 589        save_mhdr = *mhdr;
 590        *mhdr = noop_header;
 591        gru_mesq(cb, mqd->mq_gpa, gru_get_tri(mhdr), 1, IMA);
 592        ret = gru_wait(cb);
 593
 594        if (ret) {
 595                substatus = gru_get_cb_message_queue_substatus(cb);
 596                switch (substatus) {
 597                case CBSS_NO_ERROR:
 598                        STAT(mesq_noop_unexpected_error);
 599                        ret = MQE_UNEXPECTED_CB_ERR;
 600                        break;
 601                case CBSS_LB_OVERFLOWED:
 602                        STAT(mesq_noop_lb_overflow);
 603                        ret = MQE_CONGESTION;
 604                        break;
 605                case CBSS_QLIMIT_REACHED:
 606                        STAT(mesq_noop_qlimit_reached);
 607                        ret = 0;
 608                        break;
 609                case CBSS_AMO_NACKED:
 610                        STAT(mesq_noop_amo_nacked);
 611                        ret = MQE_CONGESTION;
 612                        break;
 613                case CBSS_PUT_NACKED:
 614                        STAT(mesq_noop_put_nacked);
 615                        m = mqd->mq_gpa + (gru_get_amo_value_head(cb) << 6);
 616                        gru_vstore(cb, m, gru_get_tri(mesg), XTYPE_CL, 1, 1,
 617                                                IMA);
 618                        if (gru_wait(cb) == CBS_IDLE)
 619                                ret = MQIE_AGAIN;
 620                        else
 621                                ret = MQE_UNEXPECTED_CB_ERR;
 622                        break;
 623                case CBSS_PAGE_OVERFLOW:
 624                        STAT(mesq_noop_page_overflow);
 625                        fallthrough;
 626                default:
 627                        BUG();
 628                }
 629        }
 630        *mhdr = save_mhdr;
 631        return ret;
 632}
 633
 634/*
 635 * Handle a gru_mesq full.
 636 */
 637static int send_message_queue_full(void *cb, struct gru_message_queue_desc *mqd,
 638                                void *mesg, int lines)
 639{
 640        union gru_mesqhead mqh;
 641        unsigned int limit, head;
 642        unsigned long avalue;
 643        int half, qlines;
 644
 645        /* Determine if switching to first/second half of q */
 646        avalue = gru_get_amo_value(cb);
 647        head = gru_get_amo_value_head(cb);
 648        limit = gru_get_amo_value_limit(cb);
 649
 650        qlines = mqd->qlines;
 651        half = (limit != qlines);
 652
 653        if (half)
 654                mqh = gru_mesq_head(qlines / 2 + 1, qlines);
 655        else
 656                mqh = gru_mesq_head(2, qlines / 2 + 1);
 657
 658        /* Try to get lock for switching head pointer */
 659        gru_gamir(cb, EOP_IR_CLR, HSTATUS(mqd->mq_gpa, half), XTYPE_DW, IMA);
 660        if (gru_wait(cb) != CBS_IDLE)
 661                goto cberr;
 662        if (!gru_get_amo_value(cb)) {
 663                STAT(mesq_qf_locked);
 664                return MQE_QUEUE_FULL;
 665        }
 666
 667        /* Got the lock. Send optional NOP if queue not full, */
 668        if (head != limit) {
 669                if (send_noop_message(cb, mqd, mesg)) {
 670                        gru_gamir(cb, EOP_IR_INC, HSTATUS(mqd->mq_gpa, half),
 671                                        XTYPE_DW, IMA);
 672                        if (gru_wait(cb) != CBS_IDLE)
 673                                goto cberr;
 674                        STAT(mesq_qf_noop_not_full);
 675                        return MQIE_AGAIN;
 676                }
 677                avalue++;
 678        }
 679
 680        /* Then flip queuehead to other half of queue. */
 681        gru_gamer(cb, EOP_ERR_CSWAP, mqd->mq_gpa, XTYPE_DW, mqh.val, avalue,
 682                                                        IMA);
 683        if (gru_wait(cb) != CBS_IDLE)
 684                goto cberr;
 685
 686        /* If not successfully in swapping queue head, clear the hstatus lock */
 687        if (gru_get_amo_value(cb) != avalue) {
 688                STAT(mesq_qf_switch_head_failed);
 689                gru_gamir(cb, EOP_IR_INC, HSTATUS(mqd->mq_gpa, half), XTYPE_DW,
 690                                                        IMA);
 691                if (gru_wait(cb) != CBS_IDLE)
 692                        goto cberr;
 693        }
 694        return MQIE_AGAIN;
 695cberr:
 696        STAT(mesq_qf_unexpected_error);
 697        return MQE_UNEXPECTED_CB_ERR;
 698}
 699
 700/*
 701 * Handle a PUT failure. Note: if message was a 2-line message, one of the
 702 * lines might have successfully have been written. Before sending the
 703 * message, "present" must be cleared in BOTH lines to prevent the receiver
 704 * from prematurely seeing the full message.
 705 */
 706static int send_message_put_nacked(void *cb, struct gru_message_queue_desc *mqd,
 707                        void *mesg, int lines)
 708{
 709        unsigned long m;
 710        int ret, loops = 200;   /* experimentally determined */
 711
 712        m = mqd->mq_gpa + (gru_get_amo_value_head(cb) << 6);
 713        if (lines == 2) {
 714                gru_vset(cb, m, 0, XTYPE_CL, lines, 1, IMA);
 715                if (gru_wait(cb) != CBS_IDLE)
 716                        return MQE_UNEXPECTED_CB_ERR;
 717        }
 718        gru_vstore(cb, m, gru_get_tri(mesg), XTYPE_CL, lines, 1, IMA);
 719        if (gru_wait(cb) != CBS_IDLE)
 720                return MQE_UNEXPECTED_CB_ERR;
 721
 722        if (!mqd->interrupt_vector)
 723                return MQE_OK;
 724
 725        /*
 726         * Send a noop message in order to deliver a cross-partition interrupt
 727         * to the SSI that contains the target message queue. Normally, the
 728         * interrupt is automatically delivered by hardware following mesq
 729         * operations, but some error conditions require explicit delivery.
 730         * The noop message will trigger delivery. Otherwise partition failures
 731         * could cause unrecovered errors.
 732         */
 733        do {
 734                ret = send_noop_message(cb, mqd, mesg);
 735        } while ((ret == MQIE_AGAIN || ret == MQE_CONGESTION) && (loops-- > 0));
 736
 737        if (ret == MQIE_AGAIN || ret == MQE_CONGESTION) {
 738                /*
 739                 * Don't indicate to the app to resend the message, as it's
 740                 * already been successfully sent.  We simply send an OK
 741                 * (rather than fail the send with MQE_UNEXPECTED_CB_ERR),
 742                 * assuming that the other side is receiving enough
 743                 * interrupts to get this message processed anyway.
 744                 */
 745                ret = MQE_OK;
 746        }
 747        return ret;
 748}
 749
 750/*
 751 * Handle a gru_mesq failure. Some of these failures are software recoverable
 752 * or retryable.
 753 */
 754static int send_message_failure(void *cb, struct gru_message_queue_desc *mqd,
 755                                void *mesg, int lines)
 756{
 757        int substatus, ret = 0;
 758
 759        substatus = gru_get_cb_message_queue_substatus(cb);
 760        switch (substatus) {
 761        case CBSS_NO_ERROR:
 762                STAT(mesq_send_unexpected_error);
 763                ret = MQE_UNEXPECTED_CB_ERR;
 764                break;
 765        case CBSS_LB_OVERFLOWED:
 766                STAT(mesq_send_lb_overflow);
 767                ret = MQE_CONGESTION;
 768                break;
 769        case CBSS_QLIMIT_REACHED:
 770                STAT(mesq_send_qlimit_reached);
 771                ret = send_message_queue_full(cb, mqd, mesg, lines);
 772                break;
 773        case CBSS_AMO_NACKED:
 774                STAT(mesq_send_amo_nacked);
 775                ret = MQE_CONGESTION;
 776                break;
 777        case CBSS_PUT_NACKED:
 778                STAT(mesq_send_put_nacked);
 779                ret = send_message_put_nacked(cb, mqd, mesg, lines);
 780                break;
 781        case CBSS_PAGE_OVERFLOW:
 782                STAT(mesq_page_overflow);
 783                fallthrough;
 784        default:
 785                BUG();
 786        }
 787        return ret;
 788}
 789
 790/*
 791 * Send a message to a message queue
 792 *      mqd     message queue descriptor
 793 *      mesg    message. ust be vaddr within a GSEG
 794 *      bytes   message size (<= 2 CL)
 795 */
 796int gru_send_message_gpa(struct gru_message_queue_desc *mqd, void *mesg,
 797                                unsigned int bytes)
 798{
 799        struct message_header *mhdr;
 800        void *cb;
 801        void *dsr;
 802        int istatus, clines, ret;
 803
 804        STAT(mesq_send);
 805        BUG_ON(bytes < sizeof(int) || bytes > 2 * GRU_CACHE_LINE_BYTES);
 806
 807        clines = DIV_ROUND_UP(bytes, GRU_CACHE_LINE_BYTES);
 808        if (gru_get_cpu_resources(bytes, &cb, &dsr))
 809                return MQE_BUG_NO_RESOURCES;
 810        memcpy(dsr, mesg, bytes);
 811        mhdr = dsr;
 812        mhdr->present = MQS_FULL;
 813        mhdr->lines = clines;
 814        if (clines == 2) {
 815                mhdr->present2 = get_present2(mhdr);
 816                restore_present2(mhdr, MQS_FULL);
 817        }
 818
 819        do {
 820                ret = MQE_OK;
 821                gru_mesq(cb, mqd->mq_gpa, gru_get_tri(mhdr), clines, IMA);
 822                istatus = gru_wait(cb);
 823                if (istatus != CBS_IDLE)
 824                        ret = send_message_failure(cb, mqd, dsr, clines);
 825        } while (ret == MQIE_AGAIN);
 826        gru_free_cpu_resources(cb, dsr);
 827
 828        if (ret)
 829                STAT(mesq_send_failed);
 830        return ret;
 831}
 832EXPORT_SYMBOL_GPL(gru_send_message_gpa);
 833
 834/*
 835 * Advance the receive pointer for the queue to the next message.
 836 */
 837void gru_free_message(struct gru_message_queue_desc *mqd, void *mesg)
 838{
 839        struct message_queue *mq = mqd->mq;
 840        struct message_header *mhdr = mq->next;
 841        void *next, *pnext;
 842        int half = -1;
 843        int lines = mhdr->lines;
 844
 845        if (lines == 2)
 846                restore_present2(mhdr, MQS_EMPTY);
 847        mhdr->present = MQS_EMPTY;
 848
 849        pnext = mq->next;
 850        next = pnext + GRU_CACHE_LINE_BYTES * lines;
 851        if (next == mq->limit) {
 852                next = mq->start;
 853                half = 1;
 854        } else if (pnext < mq->start2 && next >= mq->start2) {
 855                half = 0;
 856        }
 857
 858        if (half >= 0)
 859                mq->hstatus[half] = 1;
 860        mq->next = next;
 861}
 862EXPORT_SYMBOL_GPL(gru_free_message);
 863
 864/*
 865 * Get next message from message queue. Return NULL if no message
 866 * present. User must call next_message() to move to next message.
 867 *      rmq     message queue
 868 */
 869void *gru_get_next_message(struct gru_message_queue_desc *mqd)
 870{
 871        struct message_queue *mq = mqd->mq;
 872        struct message_header *mhdr = mq->next;
 873        int present = mhdr->present;
 874
 875        /* skip NOOP messages */
 876        while (present == MQS_NOOP) {
 877                gru_free_message(mqd, mhdr);
 878                mhdr = mq->next;
 879                present = mhdr->present;
 880        }
 881
 882        /* Wait for both halves of 2 line messages */
 883        if (present == MQS_FULL && mhdr->lines == 2 &&
 884                                get_present2(mhdr) == MQS_EMPTY)
 885                present = MQS_EMPTY;
 886
 887        if (!present) {
 888                STAT(mesq_receive_none);
 889                return NULL;
 890        }
 891
 892        if (mhdr->lines == 2)
 893                restore_present2(mhdr, mhdr->present2);
 894
 895        STAT(mesq_receive);
 896        return mhdr;
 897}
 898EXPORT_SYMBOL_GPL(gru_get_next_message);
 899
 900/* ---------------------- GRU DATA COPY FUNCTIONS ---------------------------*/
 901
 902/*
 903 * Load a DW from a global GPA. The GPA can be a memory or MMR address.
 904 */
 905int gru_read_gpa(unsigned long *value, unsigned long gpa)
 906{
 907        void *cb;
 908        void *dsr;
 909        int ret, iaa;
 910
 911        STAT(read_gpa);
 912        if (gru_get_cpu_resources(GRU_NUM_KERNEL_DSR_BYTES, &cb, &dsr))
 913                return MQE_BUG_NO_RESOURCES;
 914        iaa = gpa >> 62;
 915        gru_vload_phys(cb, gpa, gru_get_tri(dsr), iaa, IMA);
 916        ret = gru_wait(cb);
 917        if (ret == CBS_IDLE)
 918                *value = *(unsigned long *)dsr;
 919        gru_free_cpu_resources(cb, dsr);
 920        return ret;
 921}
 922EXPORT_SYMBOL_GPL(gru_read_gpa);
 923
 924
 925/*
 926 * Copy a block of data using the GRU resources
 927 */
 928int gru_copy_gpa(unsigned long dest_gpa, unsigned long src_gpa,
 929                                unsigned int bytes)
 930{
 931        void *cb;
 932        void *dsr;
 933        int ret;
 934
 935        STAT(copy_gpa);
 936        if (gru_get_cpu_resources(GRU_NUM_KERNEL_DSR_BYTES, &cb, &dsr))
 937                return MQE_BUG_NO_RESOURCES;
 938        gru_bcopy(cb, src_gpa, dest_gpa, gru_get_tri(dsr),
 939                  XTYPE_B, bytes, GRU_NUM_KERNEL_DSR_CL, IMA);
 940        ret = gru_wait(cb);
 941        gru_free_cpu_resources(cb, dsr);
 942        return ret;
 943}
 944EXPORT_SYMBOL_GPL(gru_copy_gpa);
 945
 946/* ------------------- KERNEL QUICKTESTS RUN AT STARTUP ----------------*/
 947/*      Temp - will delete after we gain confidence in the GRU          */
 948
 949static int quicktest0(unsigned long arg)
 950{
 951        unsigned long word0;
 952        unsigned long word1;
 953        void *cb;
 954        void *dsr;
 955        unsigned long *p;
 956        int ret = -EIO;
 957
 958        if (gru_get_cpu_resources(GRU_CACHE_LINE_BYTES, &cb, &dsr))
 959                return MQE_BUG_NO_RESOURCES;
 960        p = dsr;
 961        word0 = MAGIC;
 962        word1 = 0;
 963
 964        gru_vload(cb, uv_gpa(&word0), gru_get_tri(dsr), XTYPE_DW, 1, 1, IMA);
 965        if (gru_wait(cb) != CBS_IDLE) {
 966                printk(KERN_DEBUG "GRU:%d quicktest0: CBR failure 1\n", smp_processor_id());
 967                goto done;
 968        }
 969
 970        if (*p != MAGIC) {
 971                printk(KERN_DEBUG "GRU:%d quicktest0 bad magic 0x%lx\n", smp_processor_id(), *p);
 972                goto done;
 973        }
 974        gru_vstore(cb, uv_gpa(&word1), gru_get_tri(dsr), XTYPE_DW, 1, 1, IMA);
 975        if (gru_wait(cb) != CBS_IDLE) {
 976                printk(KERN_DEBUG "GRU:%d quicktest0: CBR failure 2\n", smp_processor_id());
 977                goto done;
 978        }
 979
 980        if (word0 != word1 || word1 != MAGIC) {
 981                printk(KERN_DEBUG
 982                       "GRU:%d quicktest0 err: found 0x%lx, expected 0x%lx\n",
 983                     smp_processor_id(), word1, MAGIC);
 984                goto done;
 985        }
 986        ret = 0;
 987
 988done:
 989        gru_free_cpu_resources(cb, dsr);
 990        return ret;
 991}
 992
 993#define ALIGNUP(p, q)   ((void *)(((unsigned long)(p) + (q) - 1) & ~(q - 1)))
 994
 995static int quicktest1(unsigned long arg)
 996{
 997        struct gru_message_queue_desc mqd;
 998        void *p, *mq;
 999        int i, ret = -EIO;
1000        char mes[GRU_CACHE_LINE_BYTES], *m;
1001
1002        /* Need  1K cacheline aligned that does not cross page boundary */
1003        p = kmalloc(4096, 0);
1004        if (p == NULL)
1005                return -ENOMEM;
1006        mq = ALIGNUP(p, 1024);
1007        memset(mes, 0xee, sizeof(mes));
1008
1009        gru_create_message_queue(&mqd, mq, 8 * GRU_CACHE_LINE_BYTES, 0, 0, 0);
1010        for (i = 0; i < 6; i++) {
1011                mes[8] = i;
1012                do {
1013                        ret = gru_send_message_gpa(&mqd, mes, sizeof(mes));
1014                } while (ret == MQE_CONGESTION);
1015                if (ret)
1016                        break;
1017        }
1018        if (ret != MQE_QUEUE_FULL || i != 4) {
1019                printk(KERN_DEBUG "GRU:%d quicktest1: unexpected status %d, i %d\n",
1020                       smp_processor_id(), ret, i);
1021                goto done;
1022        }
1023
1024        for (i = 0; i < 6; i++) {
1025                m = gru_get_next_message(&mqd);
1026                if (!m || m[8] != i)
1027                        break;
1028                gru_free_message(&mqd, m);
1029        }
1030        if (i != 4) {
1031                printk(KERN_DEBUG "GRU:%d quicktest2: bad message, i %d, m %p, m8 %d\n",
1032                        smp_processor_id(), i, m, m ? m[8] : -1);
1033                goto done;
1034        }
1035        ret = 0;
1036
1037done:
1038        kfree(p);
1039        return ret;
1040}
1041
1042static int quicktest2(unsigned long arg)
1043{
1044        static DECLARE_COMPLETION(cmp);
1045        unsigned long han;
1046        int blade_id = 0;
1047        int numcb = 4;
1048        int ret = 0;
1049        unsigned long *buf;
1050        void *cb0, *cb;
1051        struct gru_control_block_status *gen;
1052        int i, k, istatus, bytes;
1053
1054        bytes = numcb * 4 * 8;
1055        buf = kmalloc(bytes, GFP_KERNEL);
1056        if (!buf)
1057                return -ENOMEM;
1058
1059        ret = -EBUSY;
1060        han = gru_reserve_async_resources(blade_id, numcb, 0, &cmp);
1061        if (!han)
1062                goto done;
1063
1064        gru_lock_async_resource(han, &cb0, NULL);
1065        memset(buf, 0xee, bytes);
1066        for (i = 0; i < numcb; i++)
1067                gru_vset(cb0 + i * GRU_HANDLE_STRIDE, uv_gpa(&buf[i * 4]), 0,
1068                                XTYPE_DW, 4, 1, IMA_INTERRUPT);
1069
1070        ret = 0;
1071        k = numcb;
1072        do {
1073                gru_wait_async_cbr(han);
1074                for (i = 0; i < numcb; i++) {
1075                        cb = cb0 + i * GRU_HANDLE_STRIDE;
1076                        istatus = gru_check_status(cb);
1077                        if (istatus != CBS_ACTIVE && istatus != CBS_CALL_OS)
1078                                break;
1079                }
1080                if (i == numcb)
1081                        continue;
1082                if (istatus != CBS_IDLE) {
1083                        printk(KERN_DEBUG "GRU:%d quicktest2: cb %d, exception\n", smp_processor_id(), i);
1084                        ret = -EFAULT;
1085                } else if (buf[4 * i] || buf[4 * i + 1] || buf[4 * i + 2] ||
1086                                buf[4 * i + 3]) {
1087                        printk(KERN_DEBUG "GRU:%d quicktest2:cb %d,  buf 0x%lx, 0x%lx, 0x%lx, 0x%lx\n",
1088                               smp_processor_id(), i, buf[4 * i], buf[4 * i + 1], buf[4 * i + 2], buf[4 * i + 3]);
1089                        ret = -EIO;
1090                }
1091                k--;
1092                gen = cb;
1093                gen->istatus = CBS_CALL_OS; /* don't handle this CBR again */
1094        } while (k);
1095        BUG_ON(cmp.done);
1096
1097        gru_unlock_async_resource(han);
1098        gru_release_async_resources(han);
1099done:
1100        kfree(buf);
1101        return ret;
1102}
1103
1104#define BUFSIZE 200
1105static int quicktest3(unsigned long arg)
1106{
1107        char buf1[BUFSIZE], buf2[BUFSIZE];
1108        int ret = 0;
1109
1110        memset(buf2, 0, sizeof(buf2));
1111        memset(buf1, get_cycles() & 255, sizeof(buf1));
1112        gru_copy_gpa(uv_gpa(buf2), uv_gpa(buf1), BUFSIZE);
1113        if (memcmp(buf1, buf2, BUFSIZE)) {
1114                printk(KERN_DEBUG "GRU:%d quicktest3 error\n", smp_processor_id());
1115                ret = -EIO;
1116        }
1117        return ret;
1118}
1119
1120/*
1121 * Debugging only. User hook for various kernel tests
1122 * of driver & gru.
1123 */
1124int gru_ktest(unsigned long arg)
1125{
1126        int ret = -EINVAL;
1127
1128        switch (arg & 0xff) {
1129        case 0:
1130                ret = quicktest0(arg);
1131                break;
1132        case 1:
1133                ret = quicktest1(arg);
1134                break;
1135        case 2:
1136                ret = quicktest2(arg);
1137                break;
1138        case 3:
1139                ret = quicktest3(arg);
1140                break;
1141        case 99:
1142                ret = gru_free_kernel_contexts();
1143                break;
1144        }
1145        return ret;
1146
1147}
1148
1149int gru_kservices_init(void)
1150{
1151        return 0;
1152}
1153
1154void gru_kservices_exit(void)
1155{
1156        if (gru_free_kernel_contexts())
1157                BUG();
1158}
1159
1160