1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/arch/alpha/kernel/smp.c 4 * 5 * 2001-07-09 Phil Ezolt (Phillip.Ezolt@compaq.com) 6 * Renamed modified smp_call_function to smp_call_function_on_cpu() 7 * Created an function that conforms to the old calling convention 8 * of smp_call_function(). 9 * 10 * This is helpful for DCPI. 11 * 12 */ 13 14 #include <linux/errno.h> 15 #include <linux/kernel.h> 16 #include <linux/kernel_stat.h> 17 #include <linux/module.h> 18 #include <linux/sched/mm.h> 19 #include <linux/mm.h> 20 #include <linux/err.h> 21 #include <linux/threads.h> 22 #include <linux/smp.h> 23 #include <linux/interrupt.h> 24 #include <linux/init.h> 25 #include <linux/delay.h> 26 #include <linux/spinlock.h> 27 #include <linux/irq.h> 28 #include <linux/cache.h> 29 #include <linux/profile.h> 30 #include <linux/bitops.h> 31 #include <linux/cpu.h> 32 33 #include <asm/hwrpb.h> 34 #include <asm/ptrace.h> 35 #include <linux/atomic.h> 36 37 #include <asm/io.h> 38 #include <asm/irq.h> 39 #include <asm/mmu_context.h> 40 #include <asm/tlbflush.h> 41 42 #include "proto.h" 43 #include "irq_impl.h" 44 45 46 #define DEBUG_SMP 0 47 #if DEBUG_SMP 48 #define DBGS(args) printk args 49 #else 50 #define DBGS(args) 51 #endif 52 53 /* A collection of per-processor data. */ 54 struct cpuinfo_alpha cpu_data[NR_CPUS]; 55 EXPORT_SYMBOL(cpu_data); 56 57 /* A collection of single bit ipi messages. */ 58 static struct { 59 unsigned long bits ____cacheline_aligned; 60 } ipi_data[NR_CPUS] __cacheline_aligned; 61 62 enum ipi_message_type { 63 IPI_RESCHEDULE, 64 IPI_CALL_FUNC, 65 IPI_CPU_STOP, 66 }; 67 68 /* Set to a secondary's cpuid when it comes online. */ 69 static int smp_secondary_alive = 0; 70 71 int smp_num_probed; /* Internal processor count */ 72 int smp_num_cpus = 1; /* Number that came online. */ 73 EXPORT_SYMBOL(smp_num_cpus); 74 75 /* 76 * Called by both boot and secondaries to move global data into 77 * per-processor storage. 78 */ 79 static inline void __init 80 smp_store_cpu_info(int cpuid) 81 { 82 cpu_data[cpuid].loops_per_jiffy = loops_per_jiffy; 83 cpu_data[cpuid].last_asn = ASN_FIRST_VERSION; 84 cpu_data[cpuid].need_new_asn = 0; 85 cpu_data[cpuid].asn_lock = 0; 86 } 87 88 /* 89 * Ideally sets up per-cpu profiling hooks. Doesn't do much now... 90 */ 91 static inline void __init 92 smp_setup_percpu_timer(int cpuid) 93 { 94 cpu_data[cpuid].prof_counter = 1; 95 cpu_data[cpuid].prof_multiplier = 1; 96 } 97 98 static void __init 99 wait_boot_cpu_to_stop(int cpuid) 100 { 101 unsigned long stop = jiffies + 10*HZ; 102 103 while (time_before(jiffies, stop)) { 104 if (!smp_secondary_alive) 105 return; 106 barrier(); 107 } 108 109 printk("wait_boot_cpu_to_stop: FAILED on CPU %d, hanging now\n", cpuid); 110 for (;;) 111 barrier(); 112 } 113 114 /* 115 * Where secondaries begin a life of C. 116 */ 117 void __init 118 smp_callin(void) 119 { 120 int cpuid = hard_smp_processor_id(); 121 122 if (cpu_online(cpuid)) { 123 printk("??, cpu 0x%x already present??\n", cpuid); 124 BUG(); 125 } 126 set_cpu_online(cpuid, true); 127 128 /* Turn on machine checks. */ 129 wrmces(7); 130 131 /* Set trap vectors. */ 132 trap_init(); 133 134 /* Set interrupt vector. */ 135 wrent(entInt, 0); 136 137 /* Get our local ticker going. */ 138 smp_setup_percpu_timer(cpuid); 139 init_clockevent(); 140 141 /* Call platform-specific callin, if specified */ 142 if (alpha_mv.smp_callin) 143 alpha_mv.smp_callin(); 144 145 /* All kernel threads share the same mm context. */ 146 mmgrab(&init_mm); 147 current->active_mm = &init_mm; 148 149 /* inform the notifiers about the new cpu */ 150 notify_cpu_starting(cpuid); 151 152 /* Must have completely accurate bogos. */ 153 local_irq_enable(); 154 155 /* Wait boot CPU to stop with irq enabled before running 156 calibrate_delay. */ 157 wait_boot_cpu_to_stop(cpuid); 158 mb(); 159 calibrate_delay(); 160 161 smp_store_cpu_info(cpuid); 162 /* Allow master to continue only after we written loops_per_jiffy. */ 163 wmb(); 164 smp_secondary_alive = 1; 165 166 DBGS(("smp_callin: commencing CPU %d current %p active_mm %p\n", 167 cpuid, current, current->active_mm)); 168 169 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 170 } 171 172 /* Wait until hwrpb->txrdy is clear for cpu. Return -1 on timeout. */ 173 static int 174 wait_for_txrdy (unsigned long cpumask) 175 { 176 unsigned long timeout; 177 178 if (!(hwrpb->txrdy & cpumask)) 179 return 0; 180 181 timeout = jiffies + 10*HZ; 182 while (time_before(jiffies, timeout)) { 183 if (!(hwrpb->txrdy & cpumask)) 184 return 0; 185 udelay(10); 186 barrier(); 187 } 188 189 return -1; 190 } 191 192 /* 193 * Send a message to a secondary's console. "START" is one such 194 * interesting message. ;-) 195 */ 196 static void 197 send_secondary_console_msg(char *str, int cpuid) 198 { 199 struct percpu_struct *cpu; 200 register char *cp1, *cp2; 201 unsigned long cpumask; 202 size_t len; 203 204 cpu = (struct percpu_struct *) 205 ((char*)hwrpb 206 + hwrpb->processor_offset 207 + cpuid * hwrpb->processor_size); 208 209 cpumask = (1UL << cpuid); 210 if (wait_for_txrdy(cpumask)) 211 goto timeout; 212 213 cp2 = str; 214 len = strlen(cp2); 215 *(unsigned int *)&cpu->ipc_buffer[0] = len; 216 cp1 = (char *) &cpu->ipc_buffer[1]; 217 memcpy(cp1, cp2, len); 218 219 /* atomic test and set */ 220 wmb(); 221 set_bit(cpuid, &hwrpb->rxrdy); 222 223 if (wait_for_txrdy(cpumask)) 224 goto timeout; 225 return; 226 227 timeout: 228 printk("Processor %x not ready\n", cpuid); 229 } 230 231 /* 232 * A secondary console wants to send a message. Receive it. 233 */ 234 static void 235 recv_secondary_console_msg(void) 236 { 237 int mycpu, i, cnt; 238 unsigned long txrdy = hwrpb->txrdy; 239 char *cp1, *cp2, buf[80]; 240 struct percpu_struct *cpu; 241 242 DBGS(("recv_secondary_console_msg: TXRDY 0x%lx.\n", txrdy)); 243 244 mycpu = hard_smp_processor_id(); 245 246 for (i = 0; i < NR_CPUS; i++) { 247 if (!(txrdy & (1UL << i))) 248 continue; 249 250 DBGS(("recv_secondary_console_msg: " 251 "TXRDY contains CPU %d.\n", i)); 252 253 cpu = (struct percpu_struct *) 254 ((char*)hwrpb 255 + hwrpb->processor_offset 256 + i * hwrpb->processor_size); 257 258 DBGS(("recv_secondary_console_msg: on %d from %d" 259 " HALT_REASON 0x%lx FLAGS 0x%lx\n", 260 mycpu, i, cpu->halt_reason, cpu->flags)); 261 262 cnt = cpu->ipc_buffer[0] >> 32; 263 if (cnt <= 0 || cnt >= 80) 264 strcpy(buf, "<<< BOGUS MSG >>>"); 265 else { 266 cp1 = (char *) &cpu->ipc_buffer[1]; 267 cp2 = buf; 268 memcpy(cp2, cp1, cnt); 269 cp2[cnt] = '\0'; 270 271 while ((cp2 = strchr(cp2, '\r')) != 0) { 272 *cp2 = ' '; 273 if (cp2[1] == '\n') 274 cp2[1] = ' '; 275 } 276 } 277 278 DBGS((KERN_INFO "recv_secondary_console_msg: on %d " 279 "message is '%s'\n", mycpu, buf)); 280 } 281 282 hwrpb->txrdy = 0; 283 } 284 285 /* 286 * Convince the console to have a secondary cpu begin execution. 287 */ 288 static int 289 secondary_cpu_start(int cpuid, struct task_struct *idle) 290 { 291 struct percpu_struct *cpu; 292 struct pcb_struct *hwpcb, *ipcb; 293 unsigned long timeout; 294 295 cpu = (struct percpu_struct *) 296 ((char*)hwrpb 297 + hwrpb->processor_offset 298 + cpuid * hwrpb->processor_size); 299 hwpcb = (struct pcb_struct *) cpu->hwpcb; 300 ipcb = &task_thread_info(idle)->pcb; 301 302 /* Initialize the CPU's HWPCB to something just good enough for 303 us to get started. Immediately after starting, we'll swpctx 304 to the target idle task's pcb. Reuse the stack in the mean 305 time. Precalculate the target PCBB. */ 306 hwpcb->ksp = (unsigned long)ipcb + sizeof(union thread_union) - 16; 307 hwpcb->usp = 0; 308 hwpcb->ptbr = ipcb->ptbr; 309 hwpcb->pcc = 0; 310 hwpcb->asn = 0; 311 hwpcb->unique = virt_to_phys(ipcb); 312 hwpcb->flags = ipcb->flags; 313 hwpcb->res1 = hwpcb->res2 = 0; 314 315 #if 0 316 DBGS(("KSP 0x%lx PTBR 0x%lx VPTBR 0x%lx UNIQUE 0x%lx\n", 317 hwpcb->ksp, hwpcb->ptbr, hwrpb->vptb, hwpcb->unique)); 318 #endif 319 DBGS(("Starting secondary cpu %d: state 0x%lx pal_flags 0x%lx\n", 320 cpuid, idle->state, ipcb->flags)); 321 322 /* Setup HWRPB fields that SRM uses to activate secondary CPU */ 323 hwrpb->CPU_restart = __smp_callin; 324 hwrpb->CPU_restart_data = (unsigned long) __smp_callin; 325 326 /* Recalculate and update the HWRPB checksum */ 327 hwrpb_update_checksum(hwrpb); 328 329 /* 330 * Send a "start" command to the specified processor. 331 */ 332 333 /* SRM III 3.4.1.3 */ 334 cpu->flags |= 0x22; /* turn on Context Valid and Restart Capable */ 335 cpu->flags &= ~1; /* turn off Bootstrap In Progress */ 336 wmb(); 337 338 send_secondary_console_msg("START\r\n", cpuid); 339 340 /* Wait 10 seconds for an ACK from the console. */ 341 timeout = jiffies + 10*HZ; 342 while (time_before(jiffies, timeout)) { 343 if (cpu->flags & 1) 344 goto started; 345 udelay(10); 346 barrier(); 347 } 348 printk(KERN_ERR "SMP: Processor %d failed to start.\n", cpuid); 349 return -1; 350 351 started: 352 DBGS(("secondary_cpu_start: SUCCESS for CPU %d!!!\n", cpuid)); 353 return 0; 354 } 355 356 /* 357 * Bring one cpu online. 358 */ 359 static int 360 smp_boot_one_cpu(int cpuid, struct task_struct *idle) 361 { 362 unsigned long timeout; 363 364 /* Signal the secondary to wait a moment. */ 365 smp_secondary_alive = -1; 366 367 /* Whirrr, whirrr, whirrrrrrrrr... */ 368 if (secondary_cpu_start(cpuid, idle)) 369 return -1; 370 371 /* Notify the secondary CPU it can run calibrate_delay. */ 372 mb(); 373 smp_secondary_alive = 0; 374 375 /* We've been acked by the console; wait one second for 376 the task to start up for real. */ 377 timeout = jiffies + 1*HZ; 378 while (time_before(jiffies, timeout)) { 379 if (smp_secondary_alive == 1) 380 goto alive; 381 udelay(10); 382 barrier(); 383 } 384 385 /* We failed to boot the CPU. */ 386 387 printk(KERN_ERR "SMP: Processor %d is stuck.\n", cpuid); 388 return -1; 389 390 alive: 391 /* Another "Red Snapper". */ 392 return 0; 393 } 394 395 /* 396 * Called from setup_arch. Detect an SMP system and which processors 397 * are present. 398 */ 399 void __init 400 setup_smp(void) 401 { 402 struct percpu_struct *cpubase, *cpu; 403 unsigned long i; 404 405 if (boot_cpuid != 0) { 406 printk(KERN_WARNING "SMP: Booting off cpu %d instead of 0?\n", 407 boot_cpuid); 408 } 409 410 if (hwrpb->nr_processors > 1) { 411 int boot_cpu_palrev; 412 413 DBGS(("setup_smp: nr_processors %ld\n", 414 hwrpb->nr_processors)); 415 416 cpubase = (struct percpu_struct *) 417 ((char*)hwrpb + hwrpb->processor_offset); 418 boot_cpu_palrev = cpubase->pal_revision; 419 420 for (i = 0; i < hwrpb->nr_processors; i++) { 421 cpu = (struct percpu_struct *) 422 ((char *)cpubase + i*hwrpb->processor_size); 423 if ((cpu->flags & 0x1cc) == 0x1cc) { 424 smp_num_probed++; 425 set_cpu_possible(i, true); 426 set_cpu_present(i, true); 427 cpu->pal_revision = boot_cpu_palrev; 428 } 429 430 DBGS(("setup_smp: CPU %d: flags 0x%lx type 0x%lx\n", 431 i, cpu->flags, cpu->type)); 432 DBGS(("setup_smp: CPU %d: PAL rev 0x%lx\n", 433 i, cpu->pal_revision)); 434 } 435 } else { 436 smp_num_probed = 1; 437 } 438 439 printk(KERN_INFO "SMP: %d CPUs probed -- cpu_present_mask = %lx\n", 440 smp_num_probed, cpumask_bits(cpu_present_mask)[0]); 441 } 442 443 /* 444 * Called by smp_init prepare the secondaries 445 */ 446 void __init 447 smp_prepare_cpus(unsigned int max_cpus) 448 { 449 /* Take care of some initial bookkeeping. */ 450 memset(ipi_data, 0, sizeof(ipi_data)); 451 452 current_thread_info()->cpu = boot_cpuid; 453 454 smp_store_cpu_info(boot_cpuid); 455 smp_setup_percpu_timer(boot_cpuid); 456 457 /* Nothing to do on a UP box, or when told not to. */ 458 if (smp_num_probed == 1 || max_cpus == 0) { 459 init_cpu_possible(cpumask_of(boot_cpuid)); 460 init_cpu_present(cpumask_of(boot_cpuid)); 461 printk(KERN_INFO "SMP mode deactivated.\n"); 462 return; 463 } 464 465 printk(KERN_INFO "SMP starting up secondaries.\n"); 466 467 smp_num_cpus = smp_num_probed; 468 } 469 470 void 471 smp_prepare_boot_cpu(void) 472 { 473 } 474 475 int 476 __cpu_up(unsigned int cpu, struct task_struct *tidle) 477 { 478 smp_boot_one_cpu(cpu, tidle); 479 480 return cpu_online(cpu) ? 0 : -ENOSYS; 481 } 482 483 void __init 484 smp_cpus_done(unsigned int max_cpus) 485 { 486 int cpu; 487 unsigned long bogosum = 0; 488 489 for(cpu = 0; cpu < NR_CPUS; cpu++) 490 if (cpu_online(cpu)) 491 bogosum += cpu_data[cpu].loops_per_jiffy; 492 493 printk(KERN_INFO "SMP: Total of %d processors activated " 494 "(%lu.%02lu BogoMIPS).\n", 495 num_online_cpus(), 496 (bogosum + 2500) / (500000/HZ), 497 ((bogosum + 2500) / (5000/HZ)) % 100); 498 } 499 500 static void 501 send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation) 502 { 503 int i; 504 505 mb(); 506 for_each_cpu(i, to_whom) 507 set_bit(operation, &ipi_data[i].bits); 508 509 mb(); 510 for_each_cpu(i, to_whom) 511 wripir(i); 512 } 513 514 void 515 handle_ipi(struct pt_regs *regs) 516 { 517 int this_cpu = smp_processor_id(); 518 unsigned long *pending_ipis = &ipi_data[this_cpu].bits; 519 unsigned long ops; 520 521 #if 0 522 DBGS(("handle_ipi: on CPU %d ops 0x%lx PC 0x%lx\n", 523 this_cpu, *pending_ipis, regs->pc)); 524 #endif 525 526 mb(); /* Order interrupt and bit testing. */ 527 while ((ops = xchg(pending_ipis, 0)) != 0) { 528 mb(); /* Order bit clearing and data access. */ 529 do { 530 unsigned long which; 531 532 which = ops & -ops; 533 ops &= ~which; 534 which = __ffs(which); 535 536 switch (which) { 537 case IPI_RESCHEDULE: 538 scheduler_ipi(); 539 break; 540 541 case IPI_CALL_FUNC: 542 generic_smp_call_function_interrupt(); 543 break; 544 545 case IPI_CPU_STOP: 546 halt(); 547 548 default: 549 printk(KERN_CRIT "Unknown IPI on CPU %d: %lu\n", 550 this_cpu, which); 551 break; 552 } 553 } while (ops); 554 555 mb(); /* Order data access and bit testing. */ 556 } 557 558 cpu_data[this_cpu].ipi_count++; 559 560 if (hwrpb->txrdy) 561 recv_secondary_console_msg(); 562 } 563 564 void 565 smp_send_reschedule(int cpu) 566 { 567 #ifdef DEBUG_IPI_MSG 568 if (cpu == hard_smp_processor_id()) 569 printk(KERN_WARNING 570 "smp_send_reschedule: Sending IPI to self.\n"); 571 #endif 572 send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE); 573 } 574 575 void 576 smp_send_stop(void) 577 { 578 cpumask_t to_whom; 579 cpumask_copy(&to_whom, cpu_online_mask); 580 cpumask_clear_cpu(smp_processor_id(), &to_whom); 581 #ifdef DEBUG_IPI_MSG 582 if (hard_smp_processor_id() != boot_cpu_id) 583 printk(KERN_WARNING "smp_send_stop: Not on boot cpu.\n"); 584 #endif 585 send_ipi_message(&to_whom, IPI_CPU_STOP); 586 } 587 588 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 589 { 590 send_ipi_message(mask, IPI_CALL_FUNC); 591 } 592 593 void arch_send_call_function_single_ipi(int cpu) 594 { 595 send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC); 596 } 597 598 static void 599 ipi_imb(void *ignored) 600 { 601 imb(); 602 } 603 604 void 605 smp_imb(void) 606 { 607 /* Must wait other processors to flush their icache before continue. */ 608 on_each_cpu(ipi_imb, NULL, 1); 609 } 610 EXPORT_SYMBOL(smp_imb); 611 612 static void 613 ipi_flush_tlb_all(void *ignored) 614 { 615 tbia(); 616 } 617 618 void 619 flush_tlb_all(void) 620 { 621 /* Although we don't have any data to pass, we do want to 622 synchronize with the other processors. */ 623 on_each_cpu(ipi_flush_tlb_all, NULL, 1); 624 } 625 626 #define asn_locked() (cpu_data[smp_processor_id()].asn_lock) 627 628 static void 629 ipi_flush_tlb_mm(void *x) 630 { 631 struct mm_struct *mm = x; 632 if (mm == current->active_mm && !asn_locked()) 633 flush_tlb_current(mm); 634 else 635 flush_tlb_other(mm); 636 } 637 638 void 639 flush_tlb_mm(struct mm_struct *mm) 640 { 641 preempt_disable(); 642 643 if (mm == current->active_mm) { 644 flush_tlb_current(mm); 645 if (atomic_read(&mm->mm_users) <= 1) { 646 int cpu, this_cpu = smp_processor_id(); 647 for (cpu = 0; cpu < NR_CPUS; cpu++) { 648 if (!cpu_online(cpu) || cpu == this_cpu) 649 continue; 650 if (mm->context[cpu]) 651 mm->context[cpu] = 0; 652 } 653 preempt_enable(); 654 return; 655 } 656 } 657 658 smp_call_function(ipi_flush_tlb_mm, mm, 1); 659 660 preempt_enable(); 661 } 662 EXPORT_SYMBOL(flush_tlb_mm); 663 664 struct flush_tlb_page_struct { 665 struct vm_area_struct *vma; 666 struct mm_struct *mm; 667 unsigned long addr; 668 }; 669 670 static void 671 ipi_flush_tlb_page(void *x) 672 { 673 struct flush_tlb_page_struct *data = x; 674 struct mm_struct * mm = data->mm; 675 676 if (mm == current->active_mm && !asn_locked()) 677 flush_tlb_current_page(mm, data->vma, data->addr); 678 else 679 flush_tlb_other(mm); 680 } 681 682 void 683 flush_tlb_page(struct vm_area_struct *vma, unsigned long addr) 684 { 685 struct flush_tlb_page_struct data; 686 struct mm_struct *mm = vma->vm_mm; 687 688 preempt_disable(); 689 690 if (mm == current->active_mm) { 691 flush_tlb_current_page(mm, vma, addr); 692 if (atomic_read(&mm->mm_users) <= 1) { 693 int cpu, this_cpu = smp_processor_id(); 694 for (cpu = 0; cpu < NR_CPUS; cpu++) { 695 if (!cpu_online(cpu) || cpu == this_cpu) 696 continue; 697 if (mm->context[cpu]) 698 mm->context[cpu] = 0; 699 } 700 preempt_enable(); 701 return; 702 } 703 } 704 705 data.vma = vma; 706 data.mm = mm; 707 data.addr = addr; 708 709 smp_call_function(ipi_flush_tlb_page, &data, 1); 710 711 preempt_enable(); 712 } 713 EXPORT_SYMBOL(flush_tlb_page); 714 715 void 716 flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) 717 { 718 /* On the Alpha we always flush the whole user tlb. */ 719 flush_tlb_mm(vma->vm_mm); 720 } 721 EXPORT_SYMBOL(flush_tlb_range); 722 723 static void 724 ipi_flush_icache_page(void *x) 725 { 726 struct mm_struct *mm = (struct mm_struct *) x; 727 if (mm == current->active_mm && !asn_locked()) 728 __load_new_mm_context(mm); 729 else 730 flush_tlb_other(mm); 731 } 732 733 void 734 flush_icache_user_page(struct vm_area_struct *vma, struct page *page, 735 unsigned long addr, int len) 736 { 737 struct mm_struct *mm = vma->vm_mm; 738 739 if ((vma->vm_flags & VM_EXEC) == 0) 740 return; 741 742 preempt_disable(); 743 744 if (mm == current->active_mm) { 745 __load_new_mm_context(mm); 746 if (atomic_read(&mm->mm_users) <= 1) { 747 int cpu, this_cpu = smp_processor_id(); 748 for (cpu = 0; cpu < NR_CPUS; cpu++) { 749 if (!cpu_online(cpu) || cpu == this_cpu) 750 continue; 751 if (mm->context[cpu]) 752 mm->context[cpu] = 0; 753 } 754 preempt_enable(); 755 return; 756 } 757 } 758 759 smp_call_function(ipi_flush_icache_page, mm, 1); 760 761 preempt_enable(); 762 } 763