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 (i = 0; i < max_cpus; ++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         for (i = 0; i < ncpus; ++i)
  97                 set_cpu_possible(i, true);
  98 }
  99
 100 void __init smp_prepare_boot_cpu(void)
 101 {
 102         unsigned int cpu = smp_processor_id();
 103         BUG_ON(cpu != 0);
 104         cpu_asid_cache(cpu) = ASID_USER_FIRST;
 105 }
 106
 107 void __init smp_cpus_done(unsigned int max_cpus)
 108 {
 109 }
 110
 111 static int boot_secondary_processors = 1; /* Set with xt-gdb via .xt-gdb */
 112 static DECLARE_COMPLETION(cpu_running);
 113
 114 void secondary_start_kernel(void)
 115 {
 116         struct mm_struct *mm = &init_mm;
 117         unsigned int cpu = smp_processor_id();
 118
 119         init_mmu();
 120
 121 #ifdef CONFIG_DEBUG_KERNEL
 122         if (boot_secondary_processors == 0) {
 123                 pr_debug("%s: boot_secondary_processors:%d; Hanging cpu:%d\n",
 124                         __func__, boot_secondary_processors, cpu);
 125                 for (;;)
 126                         __asm__ __volatile__ ("waiti " __stringify(LOCKLEVEL));
 127         }
 128
 129         pr_debug("%s: boot_secondary_processors:%d; Booting cpu:%d\n",
 130                 __func__, boot_secondary_processors, cpu);
 131 #endif
 132         /* Init EXCSAVE1 */
 133
 134         secondary_trap_init();
 135
 136         /* All kernel threads share the same mm context. */
 137
 138         atomic_inc(&mm->mm_users);
 139         atomic_inc(&mm->mm_count);
 140         current->active_mm = mm;
 141         cpumask_set_cpu(cpu, mm_cpumask(mm));
 142         enter_lazy_tlb(mm, current);
 143
 144         preempt_disable();
 145         trace_hardirqs_off();
 146
 147         calibrate_delay();
 148
 149         notify_cpu_starting(cpu);
 150
 151         secondary_init_irq();
 152         local_timer_setup(cpu);
 153
 154         local_irq_enable();
 155
 156         set_cpu_online(cpu, true);
 157         complete(&cpu_running);
 158
 159         cpu_startup_entry(CPUHP_ONLINE);
 160 }
 161
 162 static void mx_cpu_start(void *p)
 163 {
 164         unsigned cpu = (unsigned)p;
 165         unsigned long run_stall_mask = get_er(MPSCORE);
 166
 167         set_er(run_stall_mask & ~(1u << cpu), MPSCORE);
 168         pr_debug("%s: cpu: %d, run_stall_mask: %lx ---> %lx\n",
 169                         __func__, cpu, run_stall_mask, get_er(MPSCORE));
 170 }
 171
 172 static void mx_cpu_stop(void *p)
 173 {
 174         unsigned cpu = (unsigned)p;
 175         unsigned long run_stall_mask = get_er(MPSCORE);
 176
 177         set_er(run_stall_mask | (1u << cpu), MPSCORE);
 178         pr_debug("%s: cpu: %d, run_stall_mask: %lx ---> %lx\n",
 179                         __func__, cpu, run_stall_mask, get_er(MPSCORE));
 180 }
 181
 182 #ifdef CONFIG_HOTPLUG_CPU
 183 unsigned long cpu_start_id __cacheline_aligned;
 184 #endif
 185 unsigned long cpu_start_ccount;
 186
 187 static int boot_secondary(unsigned int cpu, struct task_struct *ts)
 188 {
 189         unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 190         unsigned long ccount;
 191         int i;
 192
 193 #ifdef CONFIG_HOTPLUG_CPU
 194         cpu_start_id = cpu;
 195         system_flush_invalidate_dcache_range(
 196                         (unsigned long)&cpu_start_id, sizeof(cpu_start_id));
 197 #endif
 198         smp_call_function_single(0, mx_cpu_start, (void *)cpu, 1);
 199
 200         for (i = 0; i < 2; ++i) {
 201                 do
 202                         ccount = get_ccount();
 203                 while (!ccount);
 204
 205                 cpu_start_ccount = ccount;
 206
 207                 while (time_before(jiffies, timeout)) {
 208                         mb();
 209                         if (!cpu_start_ccount)
 210                                 break;
 211                 }
 212
 213                 if (cpu_start_ccount) {
 214                         smp_call_function_single(0, mx_cpu_stop,
 215                                         (void *)cpu, 1);
 216                         cpu_start_ccount = 0;
 217                         return -EIO;
 218                 }
 219         }
 220         return 0;
 221 }
 222
 223 int __cpu_up(unsigned int cpu, struct task_struct *idle)
 224 {
 225         int ret = 0;
 226
 227         if (cpu_asid_cache(cpu) == 0)
 228                 cpu_asid_cache(cpu) = ASID_USER_FIRST;
 229
 230         start_info.stack = (unsigned long)task_pt_regs(idle);
 231         wmb();
 232
 233         pr_debug("%s: Calling wakeup_secondary(cpu:%d, idle:%p, sp: %08lx)\n",
 234                         __func__, cpu, idle, start_info.stack);
 235
 236         ret = boot_secondary(cpu, idle);
 237         if (ret == 0) {
 238                 wait_for_completion_timeout(&cpu_running,
 239                                 msecs_to_jiffies(1000));
 240                 if (!cpu_online(cpu))
 241                         ret = -EIO;
 242         }
 243
 244         if (ret)
 245                 pr_err("CPU %u failed to boot\n", cpu);
 246
 247         return ret;
 248 }
 249
 250 #ifdef CONFIG_HOTPLUG_CPU
 251
 252 /*
 253  * __cpu_disable runs on the processor to be shutdown.
 254  */
 255 int __cpu_disable(void)
 256 {
 257         unsigned int cpu = smp_processor_id();
 258
 259         /*
 260          * Take this CPU offline.  Once we clear this, we can't return,
 261          * and we must not schedule until we're ready to give up the cpu.
 262          */
 263         set_cpu_online(cpu, false);
 264
 265         /*
 266          * OK - migrate IRQs away from this CPU
 267          */
 268         migrate_irqs();
 269
 270         /*
 271          * Flush user cache and TLB mappings, and then remove this CPU
 272          * from the vm mask set of all processes.
 273          */
 274         local_flush_cache_all();
 275         local_flush_tlb_all();
 276         invalidate_page_directory();
 277
 278         clear_tasks_mm_cpumask(cpu);
 279
 280         return 0;
 281 }
 282
 283 static void platform_cpu_kill(unsigned int cpu)
 284 {
 285         smp_call_function_single(0, mx_cpu_stop, (void *)cpu, true);
 286 }
 287
 288 /*
 289  * called on the thread which is asking for a CPU to be shutdown -
 290  * waits until shutdown has completed, or it is timed out.
 291  */
 292 void __cpu_die(unsigned int cpu)
 293 {
 294         unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 295         while (time_before(jiffies, timeout)) {
 296                 system_invalidate_dcache_range((unsigned long)&cpu_start_id,
 297                                 sizeof(cpu_start_id));
 298                 if (cpu_start_id == -cpu) {
 299                         platform_cpu_kill(cpu);
 300                         return;
 301                 }
 302         }
 303         pr_err("CPU%u: unable to kill\n", cpu);
 304 }
 305
 306 void arch_cpu_idle_dead(void)
 307 {
 308         cpu_die();
 309 }
 310 /*
 311  * Called from the idle thread for the CPU which has been shutdown.
 312  *
 313  * Note that we disable IRQs here, but do not re-enable them
 314  * before returning to the caller. This is also the behaviour
 315  * of the other hotplug-cpu capable cores, so presumably coming
 316  * out of idle fixes this.
 317  */
 318 void __ref cpu_die(void)
 319 {
 320         idle_task_exit();
 321         local_irq_disable();
 322         __asm__ __volatile__(
 323                         "       movi    a2, cpu_restart\n"
 324                         "       jx      a2\n");
 325 }
 326
 327 #endif /* CONFIG_HOTPLUG_CPU */
 328
 329 enum ipi_msg_type {
 330         IPI_RESCHEDULE = 0,
 331         IPI_CALL_FUNC,
 332         IPI_CPU_STOP,
 333         IPI_MAX
 334 };
 335
 336 static const struct {
 337         const char *short_text;
 338         const char *long_text;
 339 } ipi_text[] = {
 340         { .short_text = "RES", .long_text = "Rescheduling interrupts" },
 341         { .short_text = "CAL", .long_text = "Function call interrupts" },
 342         { .short_text = "DIE", .long_text = "CPU shutdown interrupts" },
 343 };
 344
 345 struct ipi_data {
 346         unsigned long ipi_count[IPI_MAX];
 347 };
 348
 349 static DEFINE_PER_CPU(struct ipi_data, ipi_data);
 350
 351 static void send_ipi_message(const struct cpumask *callmask,
 352                 enum ipi_msg_type msg_id)
 353 {
 354         int index;
 355         unsigned long mask = 0;
 356
 357         for_each_cpu(index, callmask)
 358                 if (index != smp_processor_id())
 359                         mask |= 1 << index;
 360
 361         set_er(mask, MIPISET(msg_id));
 362 }
 363
 364 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 365 {
 366         send_ipi_message(mask, IPI_CALL_FUNC);
 367 }
 368
 369 void arch_send_call_function_single_ipi(int cpu)
 370 {
 371         send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
 372 }
 373
 374 void smp_send_reschedule(int cpu)
 375 {
 376         send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 377 }
 378
 379 void smp_send_stop(void)
 380 {
 381         struct cpumask targets;
 382
 383         cpumask_copy(&targets, cpu_online_mask);
 384         cpumask_clear_cpu(smp_processor_id(), &targets);
 385         send_ipi_message(&targets, IPI_CPU_STOP);
 386 }
 387
 388 static void ipi_cpu_stop(unsigned int cpu)
 389 {
 390         set_cpu_online(cpu, false);
 391         machine_halt();
 392 }
 393
 394 irqreturn_t ipi_interrupt(int irq, void *dev_id)
 395 {
 396         unsigned int cpu = smp_processor_id();
 397         struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
 398         unsigned int msg;
 399         unsigned i;
 400
 401         msg = get_er(MIPICAUSE(cpu));
 402         for (i = 0; i < IPI_MAX; i++)
 403                 if (msg & (1 << i)) {
 404                         set_er(1 << i, MIPICAUSE(cpu));
 405                         ++ipi->ipi_count[i];
 406                 }
 407
 408         if (msg & (1 << IPI_RESCHEDULE))
 409                 scheduler_ipi();
 410         if (msg & (1 << IPI_CALL_FUNC))
 411                 generic_smp_call_function_interrupt();
 412         if (msg & (1 << IPI_CPU_STOP))
 413                 ipi_cpu_stop(cpu);
 414
 415         return IRQ_HANDLED;
 416 }
 417
 418 void show_ipi_list(struct seq_file *p, int prec)
 419 {
 420         unsigned int cpu;
 421         unsigned i;
 422
 423         for (i = 0; i < IPI_MAX; ++i) {
 424                 seq_printf(p, "%*s:", prec, ipi_text[i].short_text);
 425                 for_each_online_cpu(cpu)
 426                         seq_printf(p, " %10lu",
 427                                         per_cpu(ipi_data, cpu).ipi_count[i]);
 428                 seq_printf(p, "   %s\n", ipi_text[i].long_text);
 429         }
 430 }
 431
 432 int setup_profiling_timer(unsigned int multiplier)
 433 {
 434         pr_debug("setup_profiling_timer %d\n", multiplier);
 435         return 0;
 436 }
 437
 438 /* TLB flush functions */
 439
 440 struct flush_data {
 441         struct vm_area_struct *vma;
 442         unsigned long addr1;
 443         unsigned long addr2;
 444 };
 445
 446 static void ipi_flush_tlb_all(void *arg)
 447 {
 448         local_flush_tlb_all();
 449 }
 450
 451 void flush_tlb_all(void)
 452 {
 453         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 454 }
 455
 456 static void ipi_flush_tlb_mm(void *arg)
 457 {
 458         local_flush_tlb_mm(arg);
 459 }
 460
 461 void flush_tlb_mm(struct mm_struct *mm)
 462 {
 463         on_each_cpu(ipi_flush_tlb_mm, mm, 1);
 464 }
 465
 466 static void ipi_flush_tlb_page(void *arg)
 467 {
 468         struct flush_data *fd = arg;
 469         local_flush_tlb_page(fd->vma, fd->addr1);
 470 }
 471
 472 void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
 473 {
 474         struct flush_data fd = {
 475                 .vma = vma,
 476                 .addr1 = addr,
 477         };
 478         on_each_cpu(ipi_flush_tlb_page, &fd, 1);
 479 }
 480
 481 static void ipi_flush_tlb_range(void *arg)
 482 {
 483         struct flush_data *fd = arg;
 484         local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
 485 }
 486
 487 void flush_tlb_range(struct vm_area_struct *vma,
 488                      unsigned long start, unsigned long end)
 489 {
 490         struct flush_data fd = {
 491                 .vma = vma,
 492                 .addr1 = start,
 493                 .addr2 = end,
 494         };
 495         on_each_cpu(ipi_flush_tlb_range, &fd, 1);
 496 }
 497
 498 /* Cache flush functions */
 499
 500 static void ipi_flush_cache_all(void *arg)
 501 {
 502         local_flush_cache_all();
 503 }
 504
 505 void flush_cache_all(void)
 506 {
 507         on_each_cpu(ipi_flush_cache_all, NULL, 1);
 508 }
 509
 510 static void ipi_flush_cache_page(void *arg)
 511 {
 512         struct flush_data *fd = arg;
 513         local_flush_cache_page(fd->vma, fd->addr1, fd->addr2);
 514 }
 515
 516 void flush_cache_page(struct vm_area_struct *vma,
 517                      unsigned long address, unsigned long pfn)
 518 {
 519         struct flush_data fd = {
 520                 .vma = vma,
 521                 .addr1 = address,
 522                 .addr2 = pfn,
 523         };
 524         on_each_cpu(ipi_flush_cache_page, &fd, 1);
 525 }
 526
 527 static void ipi_flush_cache_range(void *arg)
 528 {
 529         struct flush_data *fd = arg;
 530         local_flush_cache_range(fd->vma, fd->addr1, fd->addr2);
 531 }
 532
 533 void flush_cache_range(struct vm_area_struct *vma,
 534                      unsigned long start, unsigned long end)
 535 {
 536         struct flush_data fd = {
 537                 .vma = vma,
 538                 .addr1 = start,
 539                 .addr2 = end,
 540         };
 541         on_each_cpu(ipi_flush_cache_range, &fd, 1);
 542 }
 543
 544 static void ipi_flush_icache_range(void *arg)
 545 {
 546         struct flush_data *fd = arg;
 547         local_flush_icache_range(fd->addr1, fd->addr2);
 548 }
 549
 550 void flush_icache_range(unsigned long start, unsigned long end)
 551 {
 552         struct flush_data fd = {
 553                 .addr1 = start,
 554                 .addr2 = end,
 555         };
 556         on_each_cpu(ipi_flush_icache_range, &fd, 1);
 557 }
 558
 559 /* ------------------------------------------------------------------------- */
 560
 561 static void ipi_invalidate_dcache_range(void *arg)
 562 {
 563         struct flush_data *fd = arg;
 564         __invalidate_dcache_range(fd->addr1, fd->addr2);
 565 }
 566
 567 static void system_invalidate_dcache_range(unsigned long start,
 568                 unsigned long size)
 569 {
 570         struct flush_data fd = {
 571                 .addr1 = start,
 572                 .addr2 = size,
 573         };
 574         on_each_cpu(ipi_invalidate_dcache_range, &fd, 1);
 575 }
 576
 577 static void ipi_flush_invalidate_dcache_range(void *arg)
 578 {
 579         struct flush_data *fd = arg;
 580         __flush_invalidate_dcache_range(fd->addr1, fd->addr2);
 581 }
 582
 583 static void system_flush_invalidate_dcache_range(unsigned long start,
 584                 unsigned long size)
 585 {
 586         struct flush_data fd = {
 587                 .addr1 = start,
 588                 .addr2 = size,
 589         };
 590         on_each_cpu(ipi_flush_invalidate_dcache_range, &fd, 1);
 591 }