arch/xtensa/kernel/smp.c

   1 /*
   2  * Xtensa SMP support functions.
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 2008 - 2013 Tensilica Inc.
   9  *
  10  * Chris Zankel <chris@zankel.net>
  11  * Joe Taylor <joe@tensilica.com>
  12  * Pete Delaney <piet@tensilica.com
  13  */
  14
  15 #include <linux/cpu.h>
  16 #include <linux/cpumask.h>
  17 #include <linux/delay.h>
  18 #include <linux/init.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/irqdomain.h>
  21 #include <linux/irq.h>
  22 #include <linux/kdebug.h>
  23 #include <linux/module.h>
  24 #include <linux/reboot.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/smp.h>
  27 #include <linux/thread_info.h>
  28
  29 #include <asm/cacheflush.h>
  30 #include <asm/kdebug.h>
  31 #include <asm/mmu_context.h>
  32 #include <asm/mxregs.h>
  33 #include <asm/platform.h>
  34 #include <asm/tlbflush.h>
  35 #include <asm/traps.h>
  36
  37 #ifdef CONFIG_SMP
  38 # if XCHAL_HAVE_S32C1I == 0
  39 #  error "The S32C1I option is required for SMP."
  40 # endif
  41 #endif
  42
  43 static void system_invalidate_dcache_range(unsigned long start,
  44                 unsigned long size);
  45 static void system_flush_invalidate_dcache_range(unsigned long start,
  46                 unsigned long size);
  47
  48 /* IPI (Inter Process Interrupt) */
  49
  50 #define IPI_IRQ 0
  51
  52 static irqreturn_t ipi_interrupt(int irq, void *dev_id);
  53 static struct irqaction ipi_irqaction = {
  54         .handler =      ipi_interrupt,
  55         .flags =        IRQF_PERCPU,
  56         .name =         "ipi",
  57 };
  58
  59 void ipi_init(void)
  60 {
  61         unsigned irq = irq_create_mapping(NULL, IPI_IRQ);
  62         setup_irq(irq, &ipi_irqaction);
  63 }
  64
  65 static inline unsigned int get_core_count(void)
  66 {
  67         /* Bits 18..21 of SYSCFGID contain the core count minus 1. */
  68         unsigned int syscfgid = get_er(SYSCFGID);
  69         return ((syscfgid >> 18) & 0xf) + 1;
  70 }
  71
  72 static inline int get_core_id(void)
  73 {
  74         /* Bits 0...18 of SYSCFGID contain the core id  */
  75         unsigned int core_id = get_er(SYSCFGID);
  76         return core_id & 0x3fff;
  77 }
  78
  79 void __init smp_prepare_cpus(unsigned int max_cpus)
  80 {
  81         unsigned i;
  82
  83         for_each_possible_cpu(i)
  84                 set_cpu_present(i, true);
  85 }
  86
  87 void __init smp_init_cpus(void)
  88 {
  89         unsigned i;
  90         unsigned int ncpus = get_core_count();
  91         unsigned int core_id = get_core_id();
  92
  93         pr_info("%s: Core Count = %d\n", __func__, ncpus);
  94         pr_info("%s: Core Id = %d\n", __func__, core_id);
  95
  96         if (ncpus > NR_CPUS) {
  97                 ncpus = NR_CPUS;
  98                 pr_info("%s: limiting core count by %d\n", __func__, ncpus);
  99         }
 100
 101         for (i = 0; i < ncpus; ++i)
 102                 set_cpu_possible(i, true);
 103 }
 104
 105 void __init smp_prepare_boot_cpu(void)
 106 {
 107         unsigned int cpu = smp_processor_id();
 108         BUG_ON(cpu != 0);
 109         cpu_asid_cache(cpu) = ASID_USER_FIRST;
 110 }
 111
 112 void __init smp_cpus_done(unsigned int max_cpus)
 113 {
 114 }
 115
 116 static int boot_secondary_processors = 1; /* Set with xt-gdb via .xt-gdb */
 117 static DECLARE_COMPLETION(cpu_running);
 118
 119 void secondary_start_kernel(void)
 120 {
 121         struct mm_struct *mm = &init_mm;
 122         unsigned int cpu = smp_processor_id();
 123
 124         init_mmu();
 125
 126 #ifdef CONFIG_DEBUG_KERNEL
 127         if (boot_secondary_processors == 0) {
 128                 pr_debug("%s: boot_secondary_processors:%d; Hanging cpu:%d\n",
 129                         __func__, boot_secondary_processors, cpu);
 130                 for (;;)
 131                         __asm__ __volatile__ ("waiti " __stringify(LOCKLEVEL));
 132         }
 133
 134         pr_debug("%s: boot_secondary_processors:%d; Booting cpu:%d\n",
 135                 __func__, boot_secondary_processors, cpu);
 136 #endif
 137         /* Init EXCSAVE1 */
 138
 139         secondary_trap_init();
 140
 141         /* All kernel threads share the same mm context. */
 142
 143         atomic_inc(&mm->mm_users);
 144         atomic_inc(&mm->mm_count);
 145         current->active_mm = mm;
 146         cpumask_set_cpu(cpu, mm_cpumask(mm));
 147         enter_lazy_tlb(mm, current);
 148
 149         preempt_disable();
 150         trace_hardirqs_off();
 151
 152         calibrate_delay();
 153
 154         notify_cpu_starting(cpu);
 155
 156         secondary_init_irq();
 157         local_timer_setup(cpu);
 158
 159         set_cpu_online(cpu, true);
 160
 161         local_irq_enable();
 162
 163         complete(&cpu_running);
 164
 165         cpu_startup_entry(CPUHP_ONLINE);
 166 }
 167
 168 static void mx_cpu_start(void *p)
 169 {
 170         unsigned cpu = (unsigned)p;
 171         unsigned long run_stall_mask = get_er(MPSCORE);
 172
 173         set_er(run_stall_mask & ~(1u << cpu), MPSCORE);
 174         pr_debug("%s: cpu: %d, run_stall_mask: %lx ---> %lx\n",
 175                         __func__, cpu, run_stall_mask, get_er(MPSCORE));
 176 }
 177
 178 static void mx_cpu_stop(void *p)
 179 {
 180         unsigned cpu = (unsigned)p;
 181         unsigned long run_stall_mask = get_er(MPSCORE);
 182
 183         set_er(run_stall_mask | (1u << cpu), MPSCORE);
 184         pr_debug("%s: cpu: %d, run_stall_mask: %lx ---> %lx\n",
 185                         __func__, cpu, run_stall_mask, get_er(MPSCORE));
 186 }
 187
 188 #ifdef CONFIG_HOTPLUG_CPU
 189 unsigned long cpu_start_id __cacheline_aligned;
 190 #endif
 191 unsigned long cpu_start_ccount;
 192
 193 static int boot_secondary(unsigned int cpu, struct task_struct *ts)
 194 {
 195         unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 196         unsigned long ccount;
 197         int i;
 198
 199 #ifdef CONFIG_HOTPLUG_CPU
 200         WRITE_ONCE(cpu_start_id, cpu);
 201         /* Pairs with the third memw in the cpu_restart */
 202         mb();
 203         system_flush_invalidate_dcache_range((unsigned long)&cpu_start_id,
 204                                              sizeof(cpu_start_id));
 205 #endif
 206         smp_call_function_single(0, mx_cpu_start, (void *)cpu, 1);
 207
 208         for (i = 0; i < 2; ++i) {
 209                 do
 210                         ccount = get_ccount();
 211                 while (!ccount);
 212
 213                 WRITE_ONCE(cpu_start_ccount, ccount);
 214
 215                 do {
 216                         /*
 217                          * Pairs with the first two memws in the
 218                          * .Lboot_secondary.
 219                          */
 220                         mb();
 221                         ccount = READ_ONCE(cpu_start_ccount);
 222                 } while (ccount && time_before(jiffies, timeout));
 223
 224                 if (ccount) {
 225                         smp_call_function_single(0, mx_cpu_stop,
 226                                                  (void *)cpu, 1);
 227                         WRITE_ONCE(cpu_start_ccount, 0);
 228                         return -EIO;
 229                 }
 230         }
 231         return 0;
 232 }
 233
 234 int __cpu_up(unsigned int cpu, struct task_struct *idle)
 235 {
 236         int ret = 0;
 237
 238         if (cpu_asid_cache(cpu) == 0)
 239                 cpu_asid_cache(cpu) = ASID_USER_FIRST;
 240
 241         start_info.stack = (unsigned long)task_pt_regs(idle);
 242         wmb();
 243
 244         pr_debug("%s: Calling wakeup_secondary(cpu:%d, idle:%p, sp: %08lx)\n",
 245                         __func__, cpu, idle, start_info.stack);
 246
 247         init_completion(&cpu_running);
 248         ret = boot_secondary(cpu, idle);
 249         if (ret == 0) {
 250                 wait_for_completion_timeout(&cpu_running,
 251                                 msecs_to_jiffies(1000));
 252                 if (!cpu_online(cpu))
 253                         ret = -EIO;
 254         }
 255
 256         if (ret)
 257                 pr_err("CPU %u failed to boot\n", cpu);
 258
 259         return ret;
 260 }
 261
 262 #ifdef CONFIG_HOTPLUG_CPU
 263
 264 /*
 265  * __cpu_disable runs on the processor to be shutdown.
 266  */
 267 int __cpu_disable(void)
 268 {
 269         unsigned int cpu = smp_processor_id();
 270
 271         /*
 272          * Take this CPU offline.  Once we clear this, we can't return,
 273          * and we must not schedule until we're ready to give up the cpu.
 274          */
 275         set_cpu_online(cpu, false);
 276
 277         /*
 278          * OK - migrate IRQs away from this CPU
 279          */
 280         migrate_irqs();
 281
 282         /*
 283          * Flush user cache and TLB mappings, and then remove this CPU
 284          * from the vm mask set of all processes.
 285          */
 286         local_flush_cache_all();
 287         local_flush_tlb_all();
 288         invalidate_page_directory();
 289
 290         clear_tasks_mm_cpumask(cpu);
 291
 292         return 0;
 293 }
 294
 295 static void platform_cpu_kill(unsigned int cpu)
 296 {
 297         smp_call_function_single(0, mx_cpu_stop, (void *)cpu, true);
 298 }
 299
 300 /*
 301  * called on the thread which is asking for a CPU to be shutdown -
 302  * waits until shutdown has completed, or it is timed out.
 303  */
 304 void __cpu_die(unsigned int cpu)
 305 {
 306         unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 307         while (time_before(jiffies, timeout)) {
 308                 system_invalidate_dcache_range((unsigned long)&cpu_start_id,
 309                                                sizeof(cpu_start_id));
 310                 /* Pairs with the second memw in the cpu_restart */
 311                 mb();
 312                 if (READ_ONCE(cpu_start_id) == -cpu) {
 313                         platform_cpu_kill(cpu);
 314                         return;
 315                 }
 316         }
 317         pr_err("CPU%u: unable to kill\n", cpu);
 318 }
 319
 320 void arch_cpu_idle_dead(void)
 321 {
 322         cpu_die();
 323 }
 324 /*
 325  * Called from the idle thread for the CPU which has been shutdown.
 326  *
 327  * Note that we disable IRQs here, but do not re-enable them
 328  * before returning to the caller. This is also the behaviour
 329  * of the other hotplug-cpu capable cores, so presumably coming
 330  * out of idle fixes this.
 331  */
 332 void __ref cpu_die(void)
 333 {
 334         idle_task_exit();
 335         local_irq_disable();
 336         __asm__ __volatile__(
 337                         "       movi    a2, cpu_restart\n"
 338                         "       jx      a2\n");
 339 }
 340
 341 #endif /* CONFIG_HOTPLUG_CPU */
 342
 343 enum ipi_msg_type {
 344         IPI_RESCHEDULE = 0,
 345         IPI_CALL_FUNC,
 346         IPI_CPU_STOP,
 347         IPI_MAX
 348 };
 349
 350 static const struct {
 351         const char *short_text;
 352         const char *long_text;
 353 } ipi_text[] = {
 354         { .short_text = "RES", .long_text = "Rescheduling interrupts" },
 355         { .short_text = "CAL", .long_text = "Function call interrupts" },
 356         { .short_text = "DIE", .long_text = "CPU shutdown interrupts" },
 357 };
 358
 359 struct ipi_data {
 360         unsigned long ipi_count[IPI_MAX];
 361 };
 362
 363 static DEFINE_PER_CPU(struct ipi_data, ipi_data);
 364
 365 static void send_ipi_message(const struct cpumask *callmask,
 366                 enum ipi_msg_type msg_id)
 367 {
 368         int index;
 369         unsigned long mask = 0;
 370
 371         for_each_cpu(index, callmask)
 372                 if (index != smp_processor_id())
 373                         mask |= 1 << index;
 374
 375         set_er(mask, MIPISET(msg_id));
 376 }
 377
 378 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 379 {
 380         send_ipi_message(mask, IPI_CALL_FUNC);
 381 }
 382
 383 void arch_send_call_function_single_ipi(int cpu)
 384 {
 385         send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
 386 }
 387
 388 void smp_send_reschedule(int cpu)
 389 {
 390         send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 391 }
 392
 393 void smp_send_stop(void)
 394 {
 395         struct cpumask targets;
 396
 397         cpumask_copy(&targets, cpu_online_mask);
 398         cpumask_clear_cpu(smp_processor_id(), &targets);
 399         send_ipi_message(&targets, IPI_CPU_STOP);
 400 }
 401
 402 static void ipi_cpu_stop(unsigned int cpu)
 403 {
 404         set_cpu_online(cpu, false);
 405         machine_halt();
 406 }
 407
 408 irqreturn_t ipi_interrupt(int irq, void *dev_id)
 409 {
 410         unsigned int cpu = smp_processor_id();
 411         struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
 412         unsigned int msg;
 413         unsigned i;
 414
 415         msg = get_er(MIPICAUSE(cpu));
 416         for (i = 0; i < IPI_MAX; i++)
 417                 if (msg & (1 << i)) {
 418                         set_er(1 << i, MIPICAUSE(cpu));
 419                         ++ipi->ipi_count[i];
 420                 }
 421
 422         if (msg & (1 << IPI_RESCHEDULE))
 423                 scheduler_ipi();
 424         if (msg & (1 << IPI_CALL_FUNC))
 425                 generic_smp_call_function_interrupt();
 426         if (msg & (1 << IPI_CPU_STOP))
 427                 ipi_cpu_stop(cpu);
 428
 429         return IRQ_HANDLED;
 430 }
 431
 432 void show_ipi_list(struct seq_file *p, int prec)
 433 {
 434         unsigned int cpu;
 435         unsigned i;
 436
 437         for (i = 0; i < IPI_MAX; ++i) {
 438                 seq_printf(p, "%*s:", prec, ipi_text[i].short_text);
 439                 for_each_online_cpu(cpu)
 440                         seq_printf(p, " %10lu",
 441                                         per_cpu(ipi_data, cpu).ipi_count[i]);
 442                 seq_printf(p, "   %s\n", ipi_text[i].long_text);
 443         }
 444 }
 445
 446 int setup_profiling_timer(unsigned int multiplier)
 447 {
 448         pr_debug("setup_profiling_timer %d\n", multiplier);
 449         return 0;
 450 }
 451
 452 /* TLB flush functions */
 453
 454 struct flush_data {
 455         struct vm_area_struct *vma;
 456         unsigned long addr1;
 457         unsigned long addr2;
 458 };
 459
 460 static void ipi_flush_tlb_all(void *arg)
 461 {
 462         local_flush_tlb_all();
 463 }
 464
 465 void flush_tlb_all(void)
 466 {
 467         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 468 }
 469
 470 static void ipi_flush_tlb_mm(void *arg)
 471 {
 472         local_flush_tlb_mm(arg);
 473 }
 474
 475 void flush_tlb_mm(struct mm_struct *mm)
 476 {
 477         on_each_cpu(ipi_flush_tlb_mm, mm, 1);
 478 }
 479
 480 static void ipi_flush_tlb_page(void *arg)
 481 {
 482         struct flush_data *fd = arg;
 483         local_flush_tlb_page(fd->vma, fd->addr1);
 484 }
 485
 486 void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
 487 {
 488         struct flush_data fd = {
 489                 .vma = vma,
 490                 .addr1 = addr,
 491         };
 492         on_each_cpu(ipi_flush_tlb_page, &fd, 1);
 493 }
 494
 495 static void ipi_flush_tlb_range(void *arg)
 496 {
 497         struct flush_data *fd = arg;
 498         local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
 499 }
 500
 501 void flush_tlb_range(struct vm_area_struct *vma,
 502                      unsigned long start, unsigned long end)
 503 {
 504         struct flush_data fd = {
 505                 .vma = vma,
 506                 .addr1 = start,
 507                 .addr2 = end,
 508         };
 509         on_each_cpu(ipi_flush_tlb_range, &fd, 1);
 510 }
 511
 512 static void ipi_flush_tlb_kernel_range(void *arg)
 513 {
 514         struct flush_data *fd = arg;
 515         local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
 516 }
 517
 518 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 519 {
 520         struct flush_data fd = {
 521                 .addr1 = start,
 522                 .addr2 = end,
 523         };
 524         on_each_cpu(ipi_flush_tlb_kernel_range, &fd, 1);
 525 }
 526
 527 /* Cache flush functions */
 528
 529 static void ipi_flush_cache_all(void *arg)
 530 {
 531         local_flush_cache_all();
 532 }
 533
 534 void flush_cache_all(void)
 535 {
 536         on_each_cpu(ipi_flush_cache_all, NULL, 1);
 537 }
 538
 539 static void ipi_flush_cache_page(void *arg)
 540 {
 541         struct flush_data *fd = arg;
 542         local_flush_cache_page(fd->vma, fd->addr1, fd->addr2);
 543 }
 544
 545 void flush_cache_page(struct vm_area_struct *vma,
 546                      unsigned long address, unsigned long pfn)
 547 {
 548         struct flush_data fd = {
 549                 .vma = vma,
 550                 .addr1 = address,
 551                 .addr2 = pfn,
 552         };
 553         on_each_cpu(ipi_flush_cache_page, &fd, 1);
 554 }
 555
 556 static void ipi_flush_cache_range(void *arg)
 557 {
 558         struct flush_data *fd = arg;
 559         local_flush_cache_range(fd->vma, fd->addr1, fd->addr2);
 560 }
 561
 562 void flush_cache_range(struct vm_area_struct *vma,
 563                      unsigned long start, unsigned long end)
 564 {
 565         struct flush_data fd = {
 566                 .vma = vma,
 567                 .addr1 = start,
 568                 .addr2 = end,
 569         };
 570         on_each_cpu(ipi_flush_cache_range, &fd, 1);
 571 }
 572
 573 static void ipi_flush_icache_range(void *arg)
 574 {
 575         struct flush_data *fd = arg;
 576         local_flush_icache_range(fd->addr1, fd->addr2);
 577 }
 578
 579 void flush_icache_range(unsigned long start, unsigned long end)
 580 {
 581         struct flush_data fd = {
 582                 .addr1 = start,
 583                 .addr2 = end,
 584         };
 585         on_each_cpu(ipi_flush_icache_range, &fd, 1);
 586 }
 587 EXPORT_SYMBOL(flush_icache_range);
 588
 589 /* ------------------------------------------------------------------------- */
 590
 591 static void ipi_invalidate_dcache_range(void *arg)
 592 {
 593         struct flush_data *fd = arg;
 594         __invalidate_dcache_range(fd->addr1, fd->addr2);
 595 }
 596
 597 static void system_invalidate_dcache_range(unsigned long start,
 598                 unsigned long size)
 599 {
 600         struct flush_data fd = {
 601                 .addr1 = start,
 602                 .addr2 = size,
 603         };
 604         on_each_cpu(ipi_invalidate_dcache_range, &fd, 1);
 605 }
 606
 607 static void ipi_flush_invalidate_dcache_range(void *arg)
 608 {
 609         struct flush_data *fd = arg;
 610         __flush_invalidate_dcache_range(fd->addr1, fd->addr2);
 611 }
 612
 613 static void system_flush_invalidate_dcache_range(unsigned long start,
 614                 unsigned long size)
 615 {
 616         struct flush_data fd = {
 617                 .addr1 = start,
 618                 .addr2 = size,
 619         };
 620         on_each_cpu(ipi_flush_invalidate_dcache_range, &fd, 1);
 621 }