kernel/scftorture.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // Torture test for smp_call_function() and friends.
   4 //
   5 // Copyright (C) Facebook, 2020.
   6 //
   7 // Author: Paul E. McKenney <paulmck@kernel.org>
   8
   9 #define pr_fmt(fmt) fmt
  10
  11 #include <linux/atomic.h>
  12 #include <linux/bitops.h>
  13 #include <linux/completion.h>
  14 #include <linux/cpu.h>
  15 #include <linux/delay.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/kthread.h>
  20 #include <linux/kernel.h>
  21 #include <linux/mm.h>
  22 #include <linux/module.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/notifier.h>
  25 #include <linux/percpu.h>
  26 #include <linux/rcupdate.h>
  27 #include <linux/rcupdate_trace.h>
  28 #include <linux/reboot.h>
  29 #include <linux/sched.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/smp.h>
  32 #include <linux/stat.h>
  33 #include <linux/srcu.h>
  34 #include <linux/slab.h>
  35 #include <linux/torture.h>
  36 #include <linux/types.h>
  37
  38 #define SCFTORT_STRING "scftorture"
  39 #define SCFTORT_FLAG SCFTORT_STRING ": "
  40
  41 #define VERBOSE_SCFTORTOUT(s, x...) \
  42         do { if (verbose) pr_alert(SCFTORT_FLAG s "\n", ## x); } while (0)
  43
  44 #define SCFTORTOUT_ERRSTRING(s, x...) pr_alert(SCFTORT_FLAG "!!! " s "\n", ## x)
  45
  46 MODULE_DESCRIPTION("Torture tests on the smp_call_function() family of primitives");
  47 MODULE_LICENSE("GPL");
  48 MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>");
  49
  50 // Wait until there are multiple CPUs before starting test.
  51 torture_param(int, holdoff, IS_BUILTIN(CONFIG_SCF_TORTURE_TEST) ? 10 : 0,
  52               "Holdoff time before test start (s)");
  53 torture_param(int, longwait, 0, "Include ridiculously long waits? (seconds)");
  54 torture_param(int, nthreads, -1, "# threads, defaults to -1 for all CPUs.");
  55 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  56 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable");
  57 torture_param(int, shutdown_secs, 0, "Shutdown time (ms), <= zero to disable.");
  58 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s.");
  59 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
  60 torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU hotplug.");
  61 torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
  62 torture_param(int, weight_resched, -1, "Testing weight for resched_cpu() operations.");
  63 torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations.");
  64 torture_param(int, weight_single_rpc, -1, "Testing weight for single-CPU RPC operations.");
  65 torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations.");
  66 torture_param(int, weight_many, -1, "Testing weight for multi-CPU no-wait operations.");
  67 torture_param(int, weight_many_wait, -1, "Testing weight for multi-CPU operations.");
  68 torture_param(int, weight_all, -1, "Testing weight for all-CPU no-wait operations.");
  69 torture_param(int, weight_all_wait, -1, "Testing weight for all-CPU operations.");
  70
  71 static char *torture_type = "";
  72
  73 #ifdef MODULE
  74 # define SCFTORT_SHUTDOWN 0
  75 #else
  76 # define SCFTORT_SHUTDOWN 1
  77 #endif
  78
  79 torture_param(bool, shutdown, SCFTORT_SHUTDOWN, "Shutdown at end of torture test.");
  80
  81 struct scf_statistics {
  82         struct task_struct *task;
  83         int cpu;
  84         long long n_resched;
  85         long long n_single;
  86         long long n_single_ofl;
  87         long long n_single_rpc;
  88         long long n_single_rpc_ofl;
  89         long long n_single_wait;
  90         long long n_single_wait_ofl;
  91         long long n_many;
  92         long long n_many_wait;
  93         long long n_all;
  94         long long n_all_wait;
  95 };
  96
  97 static struct scf_statistics *scf_stats_p;
  98 static struct task_struct *scf_torture_stats_task;
  99 static DEFINE_PER_CPU(long long, scf_invoked_count);
 100
 101 // Data for random primitive selection
 102 #define SCF_PRIM_RESCHED        0
 103 #define SCF_PRIM_SINGLE         1
 104 #define SCF_PRIM_SINGLE_RPC     2
 105 #define SCF_PRIM_MANY           3
 106 #define SCF_PRIM_ALL            4
 107 #define SCF_NPRIMS              8 // Need wait and no-wait versions of each,
 108                                   //  except for SCF_PRIM_RESCHED and
 109                                   //  SCF_PRIM_SINGLE_RPC.
 110
 111 static char *scf_prim_name[] = {
 112         "resched_cpu",
 113         "smp_call_function_single",
 114         "smp_call_function_single_rpc",
 115         "smp_call_function_many",
 116         "smp_call_function",
 117 };
 118
 119 struct scf_selector {
 120         unsigned long scfs_weight;
 121         int scfs_prim;
 122         bool scfs_wait;
 123 };
 124 static struct scf_selector scf_sel_array[SCF_NPRIMS];
 125 static int scf_sel_array_len;
 126 static unsigned long scf_sel_totweight;
 127
 128 // Communicate between caller and handler.
 129 struct scf_check {
 130         bool scfc_in;
 131         bool scfc_out;
 132         int scfc_cpu; // -1 for not _single().
 133         bool scfc_wait;
 134         bool scfc_rpc;
 135         struct completion scfc_completion;
 136 };
 137
 138 // Use to wait for all threads to start.
 139 static atomic_t n_started;
 140 static atomic_t n_errs;
 141 static atomic_t n_mb_in_errs;
 142 static atomic_t n_mb_out_errs;
 143 static atomic_t n_alloc_errs;
 144 static bool scfdone;
 145 static char *bangstr = "";
 146
 147 static DEFINE_TORTURE_RANDOM_PERCPU(scf_torture_rand);
 148
 149 extern void resched_cpu(int cpu); // An alternative IPI vector.
 150
 151 // Print torture statistics.  Caller must ensure serialization.
 152 static void scf_torture_stats_print(void)
 153 {
 154         int cpu;
 155         int i;
 156         long long invoked_count = 0;
 157         bool isdone = READ_ONCE(scfdone);
 158         struct scf_statistics scfs = {};
 159
 160         for_each_possible_cpu(cpu)
 161                 invoked_count += data_race(per_cpu(scf_invoked_count, cpu));
 162         for (i = 0; i < nthreads; i++) {
 163                 scfs.n_resched += scf_stats_p[i].n_resched;
 164                 scfs.n_single += scf_stats_p[i].n_single;
 165                 scfs.n_single_ofl += scf_stats_p[i].n_single_ofl;
 166                 scfs.n_single_rpc += scf_stats_p[i].n_single_rpc;
 167                 scfs.n_single_wait += scf_stats_p[i].n_single_wait;
 168                 scfs.n_single_wait_ofl += scf_stats_p[i].n_single_wait_ofl;
 169                 scfs.n_many += scf_stats_p[i].n_many;
 170                 scfs.n_many_wait += scf_stats_p[i].n_many_wait;
 171                 scfs.n_all += scf_stats_p[i].n_all;
 172                 scfs.n_all_wait += scf_stats_p[i].n_all_wait;
 173         }
 174         if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) ||
 175             atomic_read(&n_mb_out_errs) ||
 176             (!IS_ENABLED(CONFIG_KASAN) && atomic_read(&n_alloc_errs)))
 177                 bangstr = "!!! ";
 178         pr_alert("%s %sscf_invoked_count %s: %lld resched: %lld single: %lld/%lld single_ofl: %lld/%lld single_rpc: %lld single_rpc_ofl: %lld many: %lld/%lld all: %lld/%lld ",
 179                  SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count, scfs.n_resched,
 180                  scfs.n_single, scfs.n_single_wait, scfs.n_single_ofl, scfs.n_single_wait_ofl,
 181                  scfs.n_single_rpc, scfs.n_single_rpc_ofl,
 182                  scfs.n_many, scfs.n_many_wait, scfs.n_all, scfs.n_all_wait);
 183         torture_onoff_stats();
 184         pr_cont("ste: %d stnmie: %d stnmoe: %d staf: %d\n", atomic_read(&n_errs),
 185                 atomic_read(&n_mb_in_errs), atomic_read(&n_mb_out_errs),
 186                 atomic_read(&n_alloc_errs));
 187 }
 188
 189 // Periodically prints torture statistics, if periodic statistics printing
 190 // was specified via the stat_interval module parameter.
 191 static int
 192 scf_torture_stats(void *arg)
 193 {
 194         VERBOSE_TOROUT_STRING("scf_torture_stats task started");
 195         do {
 196                 schedule_timeout_interruptible(stat_interval * HZ);
 197                 scf_torture_stats_print();
 198                 torture_shutdown_absorb("scf_torture_stats");
 199         } while (!torture_must_stop());
 200         torture_kthread_stopping("scf_torture_stats");
 201         return 0;
 202 }
 203
 204 // Add a primitive to the scf_sel_array[].
 205 static void scf_sel_add(unsigned long weight, int prim, bool wait)
 206 {
 207         struct scf_selector *scfsp = &scf_sel_array[scf_sel_array_len];
 208
 209         // If no weight, if array would overflow, if computing three-place
 210         // percentages would overflow, or if the scf_prim_name[] array would
 211         // overflow, don't bother.  In the last three two cases, complain.
 212         if (!weight ||
 213             WARN_ON_ONCE(scf_sel_array_len >= ARRAY_SIZE(scf_sel_array)) ||
 214             WARN_ON_ONCE(0 - 100000 * weight <= 100000 * scf_sel_totweight) ||
 215             WARN_ON_ONCE(prim >= ARRAY_SIZE(scf_prim_name)))
 216                 return;
 217         scf_sel_totweight += weight;
 218         scfsp->scfs_weight = scf_sel_totweight;
 219         scfsp->scfs_prim = prim;
 220         scfsp->scfs_wait = wait;
 221         scf_sel_array_len++;
 222 }
 223
 224 // Dump out weighting percentages for scf_prim_name[] array.
 225 static void scf_sel_dump(void)
 226 {
 227         int i;
 228         unsigned long oldw = 0;
 229         struct scf_selector *scfsp;
 230         unsigned long w;
 231
 232         for (i = 0; i < scf_sel_array_len; i++) {
 233                 scfsp = &scf_sel_array[i];
 234                 w = (scfsp->scfs_weight - oldw) * 100000 / scf_sel_totweight;
 235                 pr_info("%s: %3lu.%03lu %s(%s)\n", __func__, w / 1000, w % 1000,
 236                         scf_prim_name[scfsp->scfs_prim],
 237                         scfsp->scfs_wait ? "wait" : "nowait");
 238                 oldw = scfsp->scfs_weight;
 239         }
 240 }
 241
 242 // Randomly pick a primitive and wait/nowait, based on weightings.
 243 static struct scf_selector *scf_sel_rand(struct torture_random_state *trsp)
 244 {
 245         int i;
 246         unsigned long w = torture_random(trsp) % (scf_sel_totweight + 1);
 247
 248         for (i = 0; i < scf_sel_array_len; i++)
 249                 if (scf_sel_array[i].scfs_weight >= w)
 250                         return &scf_sel_array[i];
 251         WARN_ON_ONCE(1);
 252         return &scf_sel_array[0];
 253 }
 254
 255 // Update statistics and occasionally burn up mass quantities of CPU time,
 256 // if told to do so via scftorture.longwait.  Otherwise, occasionally burn
 257 // a little bit.
 258 static void scf_handler(void *scfc_in)
 259 {
 260         int i;
 261         int j;
 262         unsigned long r = torture_random(this_cpu_ptr(&scf_torture_rand));
 263         struct scf_check *scfcp = scfc_in;
 264
 265         if (likely(scfcp)) {
 266                 WRITE_ONCE(scfcp->scfc_out, false); // For multiple receivers.
 267                 if (WARN_ON_ONCE(unlikely(!READ_ONCE(scfcp->scfc_in))))
 268                         atomic_inc(&n_mb_in_errs);
 269         }
 270         this_cpu_inc(scf_invoked_count);
 271         if (longwait <= 0) {
 272                 if (!(r & 0xffc0)) {
 273                         udelay(r & 0x3f);
 274                         goto out;
 275                 }
 276         }
 277         if (r & 0xfff)
 278                 goto out;
 279         r = (r >> 12);
 280         if (longwait <= 0) {
 281                 udelay((r & 0xff) + 1);
 282                 goto out;
 283         }
 284         r = r % longwait + 1;
 285         for (i = 0; i < r; i++) {
 286                 for (j = 0; j < 1000; j++) {
 287                         udelay(1000);
 288                         cpu_relax();
 289                 }
 290         }
 291 out:
 292         if (unlikely(!scfcp))
 293                 return;
 294         if (scfcp->scfc_wait) {
 295                 WRITE_ONCE(scfcp->scfc_out, true);
 296                 if (scfcp->scfc_rpc)
 297                         complete(&scfcp->scfc_completion);
 298         } else {
 299                 kfree(scfcp);
 300         }
 301 }
 302
 303 // As above, but check for correct CPU.
 304 static void scf_handler_1(void *scfc_in)
 305 {
 306         struct scf_check *scfcp = scfc_in;
 307
 308         if (likely(scfcp) && WARN_ONCE(smp_processor_id() != scfcp->scfc_cpu, "%s: Wanted CPU %d got CPU %d\n", __func__, scfcp->scfc_cpu, smp_processor_id())) {
 309                 atomic_inc(&n_errs);
 310         }
 311         scf_handler(scfcp);
 312 }
 313
 314 // Randomly do an smp_call_function*() invocation.
 315 static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_random_state *trsp)
 316 {
 317         bool allocfail = false;
 318         uintptr_t cpu;
 319         int ret = 0;
 320         struct scf_check *scfcp = NULL;
 321         struct scf_selector *scfsp = scf_sel_rand(trsp);
 322
 323         if (use_cpus_read_lock)
 324                 cpus_read_lock();
 325         else
 326                 preempt_disable();
 327         if (scfsp->scfs_prim == SCF_PRIM_SINGLE || scfsp->scfs_wait) {
 328                 scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC);
 329                 if (!scfcp) {
 330                         WARN_ON_ONCE(!IS_ENABLED(CONFIG_KASAN));
 331                         atomic_inc(&n_alloc_errs);
 332                         allocfail = true;
 333                 } else {
 334                         scfcp->scfc_cpu = -1;
 335                         scfcp->scfc_wait = scfsp->scfs_wait;
 336                         scfcp->scfc_out = false;
 337                         scfcp->scfc_rpc = false;
 338                 }
 339         }
 340         switch (scfsp->scfs_prim) {
 341         case SCF_PRIM_RESCHED:
 342                 if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST)) {
 343                         cpu = torture_random(trsp) % nr_cpu_ids;
 344                         scfp->n_resched++;
 345                         resched_cpu(cpu);
 346                         this_cpu_inc(scf_invoked_count);
 347                 }
 348                 break;
 349         case SCF_PRIM_SINGLE:
 350                 cpu = torture_random(trsp) % nr_cpu_ids;
 351                 if (scfsp->scfs_wait)
 352                         scfp->n_single_wait++;
 353                 else
 354                         scfp->n_single++;
 355                 if (scfcp) {
 356                         scfcp->scfc_cpu = cpu;
 357                         barrier(); // Prevent race-reduction compiler optimizations.
 358                         scfcp->scfc_in = true;
 359                 }
 360                 ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, scfsp->scfs_wait);
 361                 if (ret) {
 362                         if (scfsp->scfs_wait)
 363                                 scfp->n_single_wait_ofl++;
 364                         else
 365                                 scfp->n_single_ofl++;
 366                         kfree(scfcp);
 367                         scfcp = NULL;
 368                 }
 369                 break;
 370         case SCF_PRIM_SINGLE_RPC:
 371                 if (!scfcp)
 372                         break;
 373                 cpu = torture_random(trsp) % nr_cpu_ids;
 374                 scfp->n_single_rpc++;
 375                 scfcp->scfc_cpu = cpu;
 376                 scfcp->scfc_wait = true;
 377                 init_completion(&scfcp->scfc_completion);
 378                 scfcp->scfc_rpc = true;
 379                 barrier(); // Prevent race-reduction compiler optimizations.
 380                 scfcp->scfc_in = true;
 381                 ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, 0);
 382                 if (!ret) {
 383                         if (use_cpus_read_lock)
 384                                 cpus_read_unlock();
 385                         else
 386                                 preempt_enable();
 387                         wait_for_completion(&scfcp->scfc_completion);
 388                         if (use_cpus_read_lock)
 389                                 cpus_read_lock();
 390                         else
 391                                 preempt_disable();
 392                 } else {
 393                         scfp->n_single_rpc_ofl++;
 394                         kfree(scfcp);
 395                         scfcp = NULL;
 396                 }
 397                 break;
 398         case SCF_PRIM_MANY:
 399                 if (scfsp->scfs_wait)
 400                         scfp->n_many_wait++;
 401                 else
 402                         scfp->n_many++;
 403                 if (scfcp) {
 404                         barrier(); // Prevent race-reduction compiler optimizations.
 405                         scfcp->scfc_in = true;
 406                 }
 407                 smp_call_function_many(cpu_online_mask, scf_handler, scfcp, scfsp->scfs_wait);
 408                 break;
 409         case SCF_PRIM_ALL:
 410                 if (scfsp->scfs_wait)
 411                         scfp->n_all_wait++;
 412                 else
 413                         scfp->n_all++;
 414                 if (scfcp) {
 415                         barrier(); // Prevent race-reduction compiler optimizations.
 416                         scfcp->scfc_in = true;
 417                 }
 418                 smp_call_function(scf_handler, scfcp, scfsp->scfs_wait);
 419                 break;
 420         default:
 421                 WARN_ON_ONCE(1);
 422                 if (scfcp)
 423                         scfcp->scfc_out = true;
 424         }
 425         if (scfcp && scfsp->scfs_wait) {
 426                 if (WARN_ON_ONCE((num_online_cpus() > 1 || scfsp->scfs_prim == SCF_PRIM_SINGLE) &&
 427                                  !scfcp->scfc_out)) {
 428                         pr_warn("%s: Memory-ordering failure, scfs_prim: %d.\n", __func__, scfsp->scfs_prim);
 429                         atomic_inc(&n_mb_out_errs); // Leak rather than trash!
 430                 } else {
 431                         kfree(scfcp);
 432                 }
 433                 barrier(); // Prevent race-reduction compiler optimizations.
 434         }
 435         if (use_cpus_read_lock)
 436                 cpus_read_unlock();
 437         else
 438                 preempt_enable();
 439         if (allocfail)
 440                 schedule_timeout_idle((1 + longwait) * HZ);  // Let no-wait handlers complete.
 441         else if (!(torture_random(trsp) & 0xfff))
 442                 schedule_timeout_uninterruptible(1);
 443 }
 444
 445 // SCF test kthread.  Repeatedly does calls to members of the
 446 // smp_call_function() family of functions.
 447 static int scftorture_invoker(void *arg)
 448 {
 449         int cpu;
 450         int curcpu;
 451         DEFINE_TORTURE_RANDOM(rand);
 452         struct scf_statistics *scfp = (struct scf_statistics *)arg;
 453         bool was_offline = false;
 454
 455         VERBOSE_SCFTORTOUT("scftorture_invoker %d: task started", scfp->cpu);
 456         cpu = scfp->cpu % nr_cpu_ids;
 457         WARN_ON_ONCE(set_cpus_allowed_ptr(current, cpumask_of(cpu)));
 458         set_user_nice(current, MAX_NICE);
 459         if (holdoff)
 460                 schedule_timeout_interruptible(holdoff * HZ);
 461
 462         VERBOSE_SCFTORTOUT("scftorture_invoker %d: Waiting for all SCF torturers from cpu %d", scfp->cpu, raw_smp_processor_id());
 463
 464         // Make sure that the CPU is affinitized appropriately during testing.
 465         curcpu = raw_smp_processor_id();
 466         WARN_ONCE(curcpu != scfp->cpu % nr_cpu_ids,
 467                   "%s: Wanted CPU %d, running on %d, nr_cpu_ids = %d\n",
 468                   __func__, scfp->cpu, curcpu, nr_cpu_ids);
 469
 470         if (!atomic_dec_return(&n_started))
 471                 while (atomic_read_acquire(&n_started)) {
 472                         if (torture_must_stop()) {
 473                                 VERBOSE_SCFTORTOUT("scftorture_invoker %d ended before starting", scfp->cpu);
 474                                 goto end;
 475                         }
 476                         schedule_timeout_uninterruptible(1);
 477                 }
 478
 479         VERBOSE_SCFTORTOUT("scftorture_invoker %d started", scfp->cpu);
 480
 481         do {
 482                 scftorture_invoke_one(scfp, &rand);
 483                 while (cpu_is_offline(cpu) && !torture_must_stop()) {
 484                         schedule_timeout_interruptible(HZ / 5);
 485                         was_offline = true;
 486                 }
 487                 if (was_offline) {
 488                         set_cpus_allowed_ptr(current, cpumask_of(cpu));
 489                         was_offline = false;
 490                 }
 491                 cond_resched();
 492                 stutter_wait("scftorture_invoker");
 493         } while (!torture_must_stop());
 494
 495         VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu);
 496 end:
 497         torture_kthread_stopping("scftorture_invoker");
 498         return 0;
 499 }
 500
 501 static void
 502 scftorture_print_module_parms(const char *tag)
 503 {
 504         pr_alert(SCFTORT_FLAG
 505                  "--- %s:  verbose=%d holdoff=%d longwait=%d nthreads=%d onoff_holdoff=%d onoff_interval=%d shutdown_secs=%d stat_interval=%d stutter=%d use_cpus_read_lock=%d, weight_resched=%d, weight_single=%d, weight_single_rpc=%d, weight_single_wait=%d, weight_many=%d, weight_many_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag,
 506                  verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter, use_cpus_read_lock, weight_resched, weight_single, weight_single_rpc, weight_single_wait, weight_many, weight_many_wait, weight_all, weight_all_wait);
 507 }
 508
 509 static void scf_cleanup_handler(void *unused)
 510 {
 511 }
 512
 513 static void scf_torture_cleanup(void)
 514 {
 515         int i;
 516
 517         if (torture_cleanup_begin())
 518                 return;
 519
 520         WRITE_ONCE(scfdone, true);
 521         if (nthreads && scf_stats_p)
 522                 for (i = 0; i < nthreads; i++)
 523                         torture_stop_kthread("scftorture_invoker", scf_stats_p[i].task);
 524         else
 525                 goto end;
 526         smp_call_function(scf_cleanup_handler, NULL, 0);
 527         torture_stop_kthread(scf_torture_stats, scf_torture_stats_task);
 528         scf_torture_stats_print();  // -After- the stats thread is stopped!
 529         kfree(scf_stats_p);  // -After- the last stats print has completed!
 530         scf_stats_p = NULL;
 531
 532         if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) || atomic_read(&n_mb_out_errs))
 533                 scftorture_print_module_parms("End of test: FAILURE");
 534         else if (torture_onoff_failures())
 535                 scftorture_print_module_parms("End of test: LOCK_HOTPLUG");
 536         else
 537                 scftorture_print_module_parms("End of test: SUCCESS");
 538
 539 end:
 540         torture_cleanup_end();
 541 }
 542
 543 static int __init scf_torture_init(void)
 544 {
 545         long i;
 546         int firsterr = 0;
 547         unsigned long weight_resched1 = weight_resched;
 548         unsigned long weight_single1 = weight_single;
 549         unsigned long weight_single_rpc1 = weight_single_rpc;
 550         unsigned long weight_single_wait1 = weight_single_wait;
 551         unsigned long weight_many1 = weight_many;
 552         unsigned long weight_many_wait1 = weight_many_wait;
 553         unsigned long weight_all1 = weight_all;
 554         unsigned long weight_all_wait1 = weight_all_wait;
 555
 556         if (!torture_init_begin(SCFTORT_STRING, verbose))
 557                 return -EBUSY;
 558
 559         scftorture_print_module_parms("Start of test");
 560
 561         if (weight_resched <= 0 &&
 562             weight_single <= 0 && weight_single_rpc <= 0 && weight_single_wait <= 0 &&
 563             weight_many <= 0 && weight_many_wait <= 0 &&
 564             weight_all <= 0 && weight_all_wait <= 0) {
 565                 weight_resched1 = weight_resched == 0 ? 0 : 2 * nr_cpu_ids;
 566                 weight_single1 = weight_single == 0 ? 0 : 2 * nr_cpu_ids;
 567                 weight_single_rpc1 = weight_single_rpc == 0 ? 0 : 2 * nr_cpu_ids;
 568                 weight_single_wait1 = weight_single_wait == 0 ? 0 : 2 * nr_cpu_ids;
 569                 weight_many1 = weight_many == 0 ? 0 : 2;
 570                 weight_many_wait1 = weight_many_wait == 0 ? 0 : 2;
 571                 weight_all1 = weight_all == 0 ? 0 : 1;
 572                 weight_all_wait1 = weight_all_wait == 0 ? 0 : 1;
 573         } else {
 574                 if (weight_resched == -1)
 575                         weight_resched1 = 0;
 576                 if (weight_single == -1)
 577                         weight_single1 = 0;
 578                 if (weight_single_rpc == -1)
 579                         weight_single_rpc1 = 0;
 580                 if (weight_single_wait == -1)
 581                         weight_single_wait1 = 0;
 582                 if (weight_many == -1)
 583                         weight_many1 = 0;
 584                 if (weight_many_wait == -1)
 585                         weight_many_wait1 = 0;
 586                 if (weight_all == -1)
 587                         weight_all1 = 0;
 588                 if (weight_all_wait == -1)
 589                         weight_all_wait1 = 0;
 590         }
 591         if (weight_resched1 == 0 && weight_single1 == 0 && weight_single_rpc1 == 0 &&
 592             weight_single_wait1 == 0 && weight_many1 == 0 && weight_many_wait1 == 0 &&
 593             weight_all1 == 0 && weight_all_wait1 == 0) {
 594                 SCFTORTOUT_ERRSTRING("all zero weights makes no sense");
 595                 firsterr = -EINVAL;
 596                 goto unwind;
 597         }
 598         if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST))
 599                 scf_sel_add(weight_resched1, SCF_PRIM_RESCHED, false);
 600         else if (weight_resched1)
 601                 SCFTORTOUT_ERRSTRING("built as module, weight_resched ignored");
 602         scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false);
 603         scf_sel_add(weight_single_rpc1, SCF_PRIM_SINGLE_RPC, true);
 604         scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true);
 605         scf_sel_add(weight_many1, SCF_PRIM_MANY, false);
 606         scf_sel_add(weight_many_wait1, SCF_PRIM_MANY, true);
 607         scf_sel_add(weight_all1, SCF_PRIM_ALL, false);
 608         scf_sel_add(weight_all_wait1, SCF_PRIM_ALL, true);
 609         scf_sel_dump();
 610
 611         if (onoff_interval > 0) {
 612                 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, NULL);
 613                 if (torture_init_error(firsterr))
 614                         goto unwind;
 615         }
 616         if (shutdown_secs > 0) {
 617                 firsterr = torture_shutdown_init(shutdown_secs, scf_torture_cleanup);
 618                 if (torture_init_error(firsterr))
 619                         goto unwind;
 620         }
 621         if (stutter > 0) {
 622                 firsterr = torture_stutter_init(stutter, stutter);
 623                 if (torture_init_error(firsterr))
 624                         goto unwind;
 625         }
 626
 627         // Worker tasks invoking smp_call_function().
 628         if (nthreads < 0)
 629                 nthreads = num_online_cpus();
 630         scf_stats_p = kcalloc(nthreads, sizeof(scf_stats_p[0]), GFP_KERNEL);
 631         if (!scf_stats_p) {
 632                 SCFTORTOUT_ERRSTRING("out of memory");
 633                 firsterr = -ENOMEM;
 634                 goto unwind;
 635         }
 636
 637         VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads", nthreads);
 638
 639         atomic_set(&n_started, nthreads);
 640         for (i = 0; i < nthreads; i++) {
 641                 scf_stats_p[i].cpu = i;
 642                 firsterr = torture_create_kthread(scftorture_invoker, (void *)&scf_stats_p[i],
 643                                                   scf_stats_p[i].task);
 644                 if (torture_init_error(firsterr))
 645                         goto unwind;
 646         }
 647         if (stat_interval > 0) {
 648                 firsterr = torture_create_kthread(scf_torture_stats, NULL, scf_torture_stats_task);
 649                 if (torture_init_error(firsterr))
 650                         goto unwind;
 651         }
 652
 653         torture_init_end();
 654         return 0;
 655
 656 unwind:
 657         torture_init_end();
 658         scf_torture_cleanup();
 659         if (shutdown_secs) {
 660                 WARN_ON(!IS_MODULE(CONFIG_SCF_TORTURE_TEST));
 661                 kernel_power_off();
 662         }
 663         return firsterr;
 664 }
 665
 666 module_init(scf_torture_init);
 667 module_exit(scf_torture_cleanup);