1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Local APIC handling, local APIC timers 4 * 5 * (c) 1999, 2000, 2009 Ingo Molnar <mingo@redhat.com> 6 * 7 * Fixes 8 * Maciej W. Rozycki : Bits for genuine 82489DX APICs; 9 * thanks to Eric Gilmore 10 * and Rolf G. Tews 11 * for testing these extensively. 12 * Maciej W. Rozycki : Various updates and fixes. 13 * Mikael Pettersson : Power Management for UP-APIC. 14 * Pavel Machek and 15 * Mikael Pettersson : PM converted to driver model. 16 */ 17 18 #include <linux/perf_event.h> 19 #include <linux/kernel_stat.h> 20 #include <linux/mc146818rtc.h> 21 #include <linux/acpi_pmtmr.h> 22 #include <linux/bitmap.h> 23 #include <linux/clockchips.h> 24 #include <linux/interrupt.h> 25 #include <linux/memblock.h> 26 #include <linux/ftrace.h> 27 #include <linux/ioport.h> 28 #include <linux/export.h> 29 #include <linux/syscore_ops.h> 30 #include <linux/delay.h> 31 #include <linux/timex.h> 32 #include <linux/i8253.h> 33 #include <linux/dmar.h> 34 #include <linux/init.h> 35 #include <linux/cpu.h> 36 #include <linux/dmi.h> 37 #include <linux/smp.h> 38 #include <linux/mm.h> 39 40 #include <xen/xen.h> 41 42 #include <asm/trace/irq_vectors.h> 43 #include <asm/irq_remapping.h> 44 #include <asm/pc-conf-reg.h> 45 #include <asm/perf_event.h> 46 #include <asm/x86_init.h> 47 #include <linux/atomic.h> 48 #include <asm/barrier.h> 49 #include <asm/mpspec.h> 50 #include <asm/i8259.h> 51 #include <asm/proto.h> 52 #include <asm/traps.h> 53 #include <asm/apic.h> 54 #include <asm/acpi.h> 55 #include <asm/io_apic.h> 56 #include <asm/desc.h> 57 #include <asm/hpet.h> 58 #include <asm/mtrr.h> 59 #include <asm/time.h> 60 #include <asm/smp.h> 61 #include <asm/mce.h> 62 #include <asm/tsc.h> 63 #include <asm/hypervisor.h> 64 #include <asm/cpu_device_id.h> 65 #include <asm/intel-family.h> 66 #include <asm/irq_regs.h> 67 #include <asm/cpu.h> 68 69 #include "local.h" 70 71 /* Processor that is doing the boot up */ 72 u32 boot_cpu_physical_apicid __ro_after_init = BAD_APICID; 73 EXPORT_SYMBOL_GPL(boot_cpu_physical_apicid); 74 75 u8 boot_cpu_apic_version __ro_after_init; 76 77 /* 78 * This variable controls which CPUs receive external NMIs. By default, 79 * external NMIs are delivered only to the BSP. 80 */ 81 static int apic_extnmi __ro_after_init = APIC_EXTNMI_BSP; 82 83 /* 84 * Hypervisor supports 15 bits of APIC ID in MSI Extended Destination ID 85 */ 86 static bool virt_ext_dest_id __ro_after_init; 87 88 /* For parallel bootup. */ 89 unsigned long apic_mmio_base __ro_after_init; 90 91 static inline bool apic_accessible(void) 92 { 93 return x2apic_mode || apic_mmio_base; 94 } 95 96 #ifdef CONFIG_X86_32 97 /* Local APIC was disabled by the BIOS and enabled by the kernel */ 98 static int enabled_via_apicbase __ro_after_init; 99 100 /* 101 * Handle interrupt mode configuration register (IMCR). 102 * This register controls whether the interrupt signals 103 * that reach the BSP come from the master PIC or from the 104 * local APIC. Before entering Symmetric I/O Mode, either 105 * the BIOS or the operating system must switch out of 106 * PIC Mode by changing the IMCR. 107 */ 108 static inline void imcr_pic_to_apic(void) 109 { 110 /* NMI and 8259 INTR go through APIC */ 111 pc_conf_set(PC_CONF_MPS_IMCR, 0x01); 112 } 113 114 static inline void imcr_apic_to_pic(void) 115 { 116 /* NMI and 8259 INTR go directly to BSP */ 117 pc_conf_set(PC_CONF_MPS_IMCR, 0x00); 118 } 119 #endif 120 121 /* 122 * Knob to control our willingness to enable the local APIC. 123 * 124 * +1=force-enable 125 */ 126 static int force_enable_local_apic __initdata; 127 128 /* 129 * APIC command line parameters 130 */ 131 static int __init parse_lapic(char *arg) 132 { 133 if (IS_ENABLED(CONFIG_X86_32) && !arg) 134 force_enable_local_apic = 1; 135 else if (arg && !strncmp(arg, "notscdeadline", 13)) 136 setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); 137 return 0; 138 } 139 early_param("lapic", parse_lapic); 140 141 #ifdef CONFIG_X86_64 142 static int apic_calibrate_pmtmr __initdata; 143 static __init int setup_apicpmtimer(char *s) 144 { 145 apic_calibrate_pmtmr = 1; 146 notsc_setup(NULL); 147 return 1; 148 } 149 __setup("apicpmtimer", setup_apicpmtimer); 150 #endif 151 152 static unsigned long mp_lapic_addr __ro_after_init; 153 bool apic_is_disabled __ro_after_init; 154 /* Disable local APIC timer from the kernel commandline or via dmi quirk */ 155 static int disable_apic_timer __initdata; 156 /* Local APIC timer works in C2 */ 157 int local_apic_timer_c2_ok __ro_after_init; 158 EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok); 159 160 /* 161 * Debug level, exported for io_apic.c 162 */ 163 int apic_verbosity __ro_after_init; 164 165 int pic_mode __ro_after_init; 166 167 /* Have we found an MP table */ 168 int smp_found_config __ro_after_init; 169 170 static struct resource lapic_resource = { 171 .name = "Local APIC", 172 .flags = IORESOURCE_MEM | IORESOURCE_BUSY, 173 }; 174 175 unsigned int lapic_timer_period = 0; 176 177 static void apic_pm_activate(void); 178 179 /* 180 * Get the LAPIC version 181 */ 182 static inline int lapic_get_version(void) 183 { 184 return GET_APIC_VERSION(apic_read(APIC_LVR)); 185 } 186 187 /* 188 * Check, if the APIC is integrated or a separate chip 189 */ 190 static inline int lapic_is_integrated(void) 191 { 192 return APIC_INTEGRATED(lapic_get_version()); 193 } 194 195 /* 196 * Check, whether this is a modern or a first generation APIC 197 */ 198 static int modern_apic(void) 199 { 200 /* AMD systems use old APIC versions, so check the CPU */ 201 if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD && 202 boot_cpu_data.x86 >= 0xf) 203 return 1; 204 205 /* Hygon systems use modern APIC */ 206 if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) 207 return 1; 208 209 return lapic_get_version() >= 0x14; 210 } 211 212 /* 213 * right after this call apic become NOOP driven 214 * so apic->write/read doesn't do anything 215 */ 216 static void __init apic_disable(void) 217 { 218 apic_install_driver(&apic_noop); 219 } 220 221 void native_apic_icr_write(u32 low, u32 id) 222 { 223 unsigned long flags; 224 225 local_irq_save(flags); 226 apic_write(APIC_ICR2, SET_XAPIC_DEST_FIELD(id)); 227 apic_write(APIC_ICR, low); 228 local_irq_restore(flags); 229 } 230 231 u64 native_apic_icr_read(void) 232 { 233 u32 icr1, icr2; 234 235 icr2 = apic_read(APIC_ICR2); 236 icr1 = apic_read(APIC_ICR); 237 238 return icr1 | ((u64)icr2 << 32); 239 } 240 241 /** 242 * lapic_get_maxlvt - get the maximum number of local vector table entries 243 */ 244 int lapic_get_maxlvt(void) 245 { 246 /* 247 * - we always have APIC integrated on 64bit mode 248 * - 82489DXs do not report # of LVT entries 249 */ 250 return lapic_is_integrated() ? GET_APIC_MAXLVT(apic_read(APIC_LVR)) : 2; 251 } 252 253 /* 254 * Local APIC timer 255 */ 256 257 /* Clock divisor */ 258 #define APIC_DIVISOR 16 259 #define TSC_DIVISOR 8 260 261 /* i82489DX specific */ 262 #define I82489DX_BASE_DIVIDER (((0x2) << 18)) 263 264 /* 265 * This function sets up the local APIC timer, with a timeout of 266 * 'clocks' APIC bus clock. During calibration we actually call 267 * this function twice on the boot CPU, once with a bogus timeout 268 * value, second time for real. The other (noncalibrating) CPUs 269 * call this function only once, with the real, calibrated value. 270 * 271 * We do reads before writes even if unnecessary, to get around the 272 * P5 APIC double write bug. 273 */ 274 static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen) 275 { 276 unsigned int lvtt_value, tmp_value; 277 278 lvtt_value = LOCAL_TIMER_VECTOR; 279 if (!oneshot) 280 lvtt_value |= APIC_LVT_TIMER_PERIODIC; 281 else if (boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) 282 lvtt_value |= APIC_LVT_TIMER_TSCDEADLINE; 283 284 /* 285 * The i82489DX APIC uses bit 18 and 19 for the base divider. This 286 * overlaps with bit 18 on integrated APICs, but is not documented 287 * in the SDM. No problem though. i82489DX equipped systems do not 288 * have TSC deadline timer. 289 */ 290 if (!lapic_is_integrated()) 291 lvtt_value |= I82489DX_BASE_DIVIDER; 292 293 if (!irqen) 294 lvtt_value |= APIC_LVT_MASKED; 295 296 apic_write(APIC_LVTT, lvtt_value); 297 298 if (lvtt_value & APIC_LVT_TIMER_TSCDEADLINE) { 299 /* 300 * See Intel SDM: TSC-Deadline Mode chapter. In xAPIC mode, 301 * writing to the APIC LVTT and TSC_DEADLINE MSR isn't serialized. 302 * According to Intel, MFENCE can do the serialization here. 303 */ 304 asm volatile("mfence" : : : "memory"); 305 return; 306 } 307 308 /* 309 * Divide PICLK by 16 310 */ 311 tmp_value = apic_read(APIC_TDCR); 312 apic_write(APIC_TDCR, 313 (tmp_value & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE)) | 314 APIC_TDR_DIV_16); 315 316 if (!oneshot) 317 apic_write(APIC_TMICT, clocks / APIC_DIVISOR); 318 } 319 320 /* 321 * Setup extended LVT, AMD specific 322 * 323 * Software should use the LVT offsets the BIOS provides. The offsets 324 * are determined by the subsystems using it like those for MCE 325 * threshold or IBS. On K8 only offset 0 (APIC500) and MCE interrupts 326 * are supported. Beginning with family 10h at least 4 offsets are 327 * available. 328 * 329 * Since the offsets must be consistent for all cores, we keep track 330 * of the LVT offsets in software and reserve the offset for the same 331 * vector also to be used on other cores. An offset is freed by 332 * setting the entry to APIC_EILVT_MASKED. 333 * 334 * If the BIOS is right, there should be no conflicts. Otherwise a 335 * "[Firmware Bug]: ..." error message is generated. However, if 336 * software does not properly determines the offsets, it is not 337 * necessarily a BIOS bug. 338 */ 339 340 static atomic_t eilvt_offsets[APIC_EILVT_NR_MAX]; 341 342 static inline int eilvt_entry_is_changeable(unsigned int old, unsigned int new) 343 { 344 return (old & APIC_EILVT_MASKED) 345 || (new == APIC_EILVT_MASKED) 346 || ((new & ~APIC_EILVT_MASKED) == old); 347 } 348 349 static unsigned int reserve_eilvt_offset(int offset, unsigned int new) 350 { 351 unsigned int rsvd, vector; 352 353 if (offset >= APIC_EILVT_NR_MAX) 354 return ~0; 355 356 rsvd = atomic_read(&eilvt_offsets[offset]); 357 do { 358 vector = rsvd & ~APIC_EILVT_MASKED; /* 0: unassigned */ 359 if (vector && !eilvt_entry_is_changeable(vector, new)) 360 /* may not change if vectors are different */ 361 return rsvd; 362 } while (!atomic_try_cmpxchg(&eilvt_offsets[offset], &rsvd, new)); 363 364 rsvd = new & ~APIC_EILVT_MASKED; 365 if (rsvd && rsvd != vector) 366 pr_info("LVT offset %d assigned for vector 0x%02x\n", 367 offset, rsvd); 368 369 return new; 370 } 371 372 /* 373 * If mask=1, the LVT entry does not generate interrupts while mask=0 374 * enables the vector. See also the BKDGs. Must be called with 375 * preemption disabled. 376 */ 377 378 int setup_APIC_eilvt(u8 offset, u8 vector, u8 msg_type, u8 mask) 379 { 380 unsigned long reg = APIC_EILVTn(offset); 381 unsigned int new, old, reserved; 382 383 new = (mask << 16) | (msg_type << 8) | vector; 384 old = apic_read(reg); 385 reserved = reserve_eilvt_offset(offset, new); 386 387 if (reserved != new) { 388 pr_err(FW_BUG "cpu %d, try to use APIC%lX (LVT offset %d) for " 389 "vector 0x%x, but the register is already in use for " 390 "vector 0x%x on another cpu\n", 391 smp_processor_id(), reg, offset, new, reserved); 392 return -EINVAL; 393 } 394 395 if (!eilvt_entry_is_changeable(old, new)) { 396 pr_err(FW_BUG "cpu %d, try to use APIC%lX (LVT offset %d) for " 397 "vector 0x%x, but the register is already in use for " 398 "vector 0x%x on this cpu\n", 399 smp_processor_id(), reg, offset, new, old); 400 return -EBUSY; 401 } 402 403 apic_write(reg, new); 404 405 return 0; 406 } 407 EXPORT_SYMBOL_GPL(setup_APIC_eilvt); 408 409 /* 410 * Program the next event, relative to now 411 */ 412 static int lapic_next_event(unsigned long delta, 413 struct clock_event_device *evt) 414 { 415 apic_write(APIC_TMICT, delta); 416 return 0; 417 } 418 419 static int lapic_next_deadline(unsigned long delta, 420 struct clock_event_device *evt) 421 { 422 u64 tsc; 423 424 /* This MSR is special and need a special fence: */ 425 weak_wrmsr_fence(); 426 427 tsc = rdtsc(); 428 wrmsrl(MSR_IA32_TSC_DEADLINE, tsc + (((u64) delta) * TSC_DIVISOR)); 429 return 0; 430 } 431 432 static int lapic_timer_shutdown(struct clock_event_device *evt) 433 { 434 unsigned int v; 435 436 /* Lapic used as dummy for broadcast ? */ 437 if (evt->features & CLOCK_EVT_FEAT_DUMMY) 438 return 0; 439 440 v = apic_read(APIC_LVTT); 441 v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR); 442 apic_write(APIC_LVTT, v); 443 444 /* 445 * Setting APIC_LVT_MASKED (above) should be enough to tell 446 * the hardware that this timer will never fire. But AMD 447 * erratum 411 and some Intel CPU behavior circa 2024 say 448 * otherwise. Time for belt and suspenders programming: mask 449 * the timer _and_ zero the counter registers: 450 */ 451 if (v & APIC_LVT_TIMER_TSCDEADLINE) 452 wrmsrl(MSR_IA32_TSC_DEADLINE, 0); 453 else 454 apic_write(APIC_TMICT, 0); 455 456 return 0; 457 } 458 459 static inline int 460 lapic_timer_set_periodic_oneshot(struct clock_event_device *evt, bool oneshot) 461 { 462 /* Lapic used as dummy for broadcast ? */ 463 if (evt->features & CLOCK_EVT_FEAT_DUMMY) 464 return 0; 465 466 __setup_APIC_LVTT(lapic_timer_period, oneshot, 1); 467 return 0; 468 } 469 470 static int lapic_timer_set_periodic(struct clock_event_device *evt) 471 { 472 return lapic_timer_set_periodic_oneshot(evt, false); 473 } 474 475 static int lapic_timer_set_oneshot(struct clock_event_device *evt) 476 { 477 return lapic_timer_set_periodic_oneshot(evt, true); 478 } 479 480 /* 481 * Local APIC timer broadcast function 482 */ 483 static void lapic_timer_broadcast(const struct cpumask *mask) 484 { 485 #ifdef CONFIG_SMP 486 __apic_send_IPI_mask(mask, LOCAL_TIMER_VECTOR); 487 #endif 488 } 489 490 491 /* 492 * The local apic timer can be used for any function which is CPU local. 493 */ 494 static struct clock_event_device lapic_clockevent = { 495 .name = "lapic", 496 .features = CLOCK_EVT_FEAT_PERIODIC | 497 CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP 498 | CLOCK_EVT_FEAT_DUMMY, 499 .shift = 32, 500 .set_state_shutdown = lapic_timer_shutdown, 501 .set_state_periodic = lapic_timer_set_periodic, 502 .set_state_oneshot = lapic_timer_set_oneshot, 503 .set_state_oneshot_stopped = lapic_timer_shutdown, 504 .set_next_event = lapic_next_event, 505 .broadcast = lapic_timer_broadcast, 506 .rating = 100, 507 .irq = -1, 508 }; 509 static DEFINE_PER_CPU(struct clock_event_device, lapic_events); 510 511 static const struct x86_cpu_id deadline_match[] __initconst = { 512 X86_MATCH_VFM_STEPS(INTEL_HASWELL_X, 0x2, 0x2, 0x3a), /* EP */ 513 X86_MATCH_VFM_STEPS(INTEL_HASWELL_X, 0x4, 0x4, 0x0f), /* EX */ 514 515 X86_MATCH_VFM(INTEL_BROADWELL_X, 0x0b000020), 516 517 X86_MATCH_VFM_STEPS(INTEL_BROADWELL_D, 0x2, 0x2, 0x00000011), 518 X86_MATCH_VFM_STEPS(INTEL_BROADWELL_D, 0x3, 0x3, 0x0700000e), 519 X86_MATCH_VFM_STEPS(INTEL_BROADWELL_D, 0x4, 0x4, 0x0f00000c), 520 X86_MATCH_VFM_STEPS(INTEL_BROADWELL_D, 0x5, 0x5, 0x0e000003), 521 522 X86_MATCH_VFM_STEPS(INTEL_SKYLAKE_X, 0x3, 0x3, 0x01000136), 523 X86_MATCH_VFM_STEPS(INTEL_SKYLAKE_X, 0x4, 0x4, 0x02000014), 524 X86_MATCH_VFM_STEPS(INTEL_SKYLAKE_X, 0x5, 0xf, 0), 525 526 X86_MATCH_VFM(INTEL_HASWELL, 0x22), 527 X86_MATCH_VFM(INTEL_HASWELL_L, 0x20), 528 X86_MATCH_VFM(INTEL_HASWELL_G, 0x17), 529 530 X86_MATCH_VFM(INTEL_BROADWELL, 0x25), 531 X86_MATCH_VFM(INTEL_BROADWELL_G, 0x17), 532 533 X86_MATCH_VFM(INTEL_SKYLAKE_L, 0xb2), 534 X86_MATCH_VFM(INTEL_SKYLAKE, 0xb2), 535 536 X86_MATCH_VFM(INTEL_KABYLAKE_L, 0x52), 537 X86_MATCH_VFM(INTEL_KABYLAKE, 0x52), 538 539 {}, 540 }; 541 542 static __init bool apic_validate_deadline_timer(void) 543 { 544 const struct x86_cpu_id *m; 545 u32 rev; 546 547 if (!boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) 548 return false; 549 if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) 550 return true; 551 552 m = x86_match_cpu(deadline_match); 553 if (!m) 554 return true; 555 556 rev = (u32)m->driver_data; 557 558 if (boot_cpu_data.microcode >= rev) 559 return true; 560 561 setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); 562 pr_err(FW_BUG "TSC_DEADLINE disabled due to Errata; " 563 "please update microcode to version: 0x%x (or later)\n", rev); 564 return false; 565 } 566 567 /* 568 * Setup the local APIC timer for this CPU. Copy the initialized values 569 * of the boot CPU and register the clock event in the framework. 570 */ 571 static void setup_APIC_timer(void) 572 { 573 struct clock_event_device *levt = this_cpu_ptr(&lapic_events); 574 575 if (this_cpu_has(X86_FEATURE_ARAT)) { 576 lapic_clockevent.features &= ~CLOCK_EVT_FEAT_C3STOP; 577 /* Make LAPIC timer preferable over percpu HPET */ 578 lapic_clockevent.rating = 150; 579 } 580 581 memcpy(levt, &lapic_clockevent, sizeof(*levt)); 582 levt->cpumask = cpumask_of(smp_processor_id()); 583 584 if (this_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) { 585 levt->name = "lapic-deadline"; 586 levt->features &= ~(CLOCK_EVT_FEAT_PERIODIC | 587 CLOCK_EVT_FEAT_DUMMY); 588 levt->set_next_event = lapic_next_deadline; 589 clockevents_config_and_register(levt, 590 tsc_khz * (1000 / TSC_DIVISOR), 591 0xF, ~0UL); 592 } else 593 clockevents_register_device(levt); 594 } 595 596 /* 597 * Install the updated TSC frequency from recalibration at the TSC 598 * deadline clockevent devices. 599 */ 600 static void __lapic_update_tsc_freq(void *info) 601 { 602 struct clock_event_device *levt = this_cpu_ptr(&lapic_events); 603 604 if (!this_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) 605 return; 606 607 clockevents_update_freq(levt, tsc_khz * (1000 / TSC_DIVISOR)); 608 } 609 610 void lapic_update_tsc_freq(void) 611 { 612 /* 613 * The clockevent device's ->mult and ->shift can both be 614 * changed. In order to avoid races, schedule the frequency 615 * update code on each CPU. 616 */ 617 on_each_cpu(__lapic_update_tsc_freq, NULL, 0); 618 } 619 620 /* 621 * In this functions we calibrate APIC bus clocks to the external timer. 622 * 623 * We want to do the calibration only once since we want to have local timer 624 * irqs synchronous. CPUs connected by the same APIC bus have the very same bus 625 * frequency. 626 * 627 * This was previously done by reading the PIT/HPET and waiting for a wrap 628 * around to find out, that a tick has elapsed. I have a box, where the PIT 629 * readout is broken, so it never gets out of the wait loop again. This was 630 * also reported by others. 631 * 632 * Monitoring the jiffies value is inaccurate and the clockevents 633 * infrastructure allows us to do a simple substitution of the interrupt 634 * handler. 635 * 636 * The calibration routine also uses the pm_timer when possible, as the PIT 637 * happens to run way too slow (factor 2.3 on my VAIO CoreDuo, which goes 638 * back to normal later in the boot process). 639 */ 640 641 #define LAPIC_CAL_LOOPS (HZ/10) 642 643 static __initdata int lapic_cal_loops = -1; 644 static __initdata long lapic_cal_t1, lapic_cal_t2; 645 static __initdata unsigned long long lapic_cal_tsc1, lapic_cal_tsc2; 646 static __initdata u32 lapic_cal_pm1, lapic_cal_pm2; 647 static __initdata unsigned long lapic_cal_j1, lapic_cal_j2; 648 649 /* 650 * Temporary interrupt handler and polled calibration function. 651 */ 652 static void __init lapic_cal_handler(struct clock_event_device *dev) 653 { 654 unsigned long long tsc = 0; 655 long tapic = apic_read(APIC_TMCCT); 656 u32 pm = acpi_pm_read_early(); 657 658 if (boot_cpu_has(X86_FEATURE_TSC)) 659 tsc = rdtsc(); 660 661 switch (lapic_cal_loops++) { 662 case 0: 663 lapic_cal_t1 = tapic; 664 lapic_cal_tsc1 = tsc; 665 lapic_cal_pm1 = pm; 666 lapic_cal_j1 = jiffies; 667 break; 668 669 case LAPIC_CAL_LOOPS: 670 lapic_cal_t2 = tapic; 671 lapic_cal_tsc2 = tsc; 672 if (pm < lapic_cal_pm1) 673 pm += ACPI_PM_OVRRUN; 674 lapic_cal_pm2 = pm; 675 lapic_cal_j2 = jiffies; 676 break; 677 } 678 } 679 680 static int __init 681 calibrate_by_pmtimer(u32 deltapm, long *delta, long *deltatsc) 682 { 683 const long pm_100ms = PMTMR_TICKS_PER_SEC / 10; 684 const long pm_thresh = pm_100ms / 100; 685 unsigned long mult; 686 u64 res; 687 688 #ifndef CONFIG_X86_PM_TIMER 689 return -1; 690 #endif 691 692 apic_pr_verbose("... PM-Timer delta = %u\n", deltapm); 693 694 /* Check, if the PM timer is available */ 695 if (!deltapm) 696 return -1; 697 698 mult = clocksource_hz2mult(PMTMR_TICKS_PER_SEC, 22); 699 700 if (deltapm > (pm_100ms - pm_thresh) && 701 deltapm < (pm_100ms + pm_thresh)) { 702 apic_pr_verbose("... PM-Timer result ok\n"); 703 return 0; 704 } 705 706 res = (((u64)deltapm) * mult) >> 22; 707 do_div(res, 1000000); 708 pr_warn("APIC calibration not consistent with PM-Timer: %ldms instead of 100ms\n", 709 (long)res); 710 711 /* Correct the lapic counter value */ 712 res = (((u64)(*delta)) * pm_100ms); 713 do_div(res, deltapm); 714 pr_info("APIC delta adjusted to PM-Timer: " 715 "%lu (%ld)\n", (unsigned long)res, *delta); 716 *delta = (long)res; 717 718 /* Correct the tsc counter value */ 719 if (boot_cpu_has(X86_FEATURE_TSC)) { 720 res = (((u64)(*deltatsc)) * pm_100ms); 721 do_div(res, deltapm); 722 apic_pr_verbose("TSC delta adjusted to PM-Timer: %lu (%ld)\n", 723 (unsigned long)res, *deltatsc); 724 *deltatsc = (long)res; 725 } 726 727 return 0; 728 } 729 730 static int __init lapic_init_clockevent(void) 731 { 732 if (!lapic_timer_period) 733 return -1; 734 735 /* Calculate the scaled math multiplication factor */ 736 lapic_clockevent.mult = div_sc(lapic_timer_period/APIC_DIVISOR, 737 TICK_NSEC, lapic_clockevent.shift); 738 lapic_clockevent.max_delta_ns = 739 clockevent_delta2ns(0x7FFFFFFF, &lapic_clockevent); 740 lapic_clockevent.max_delta_ticks = 0x7FFFFFFF; 741 lapic_clockevent.min_delta_ns = 742 clockevent_delta2ns(0xF, &lapic_clockevent); 743 lapic_clockevent.min_delta_ticks = 0xF; 744 745 return 0; 746 } 747 748 bool __init apic_needs_pit(void) 749 { 750 /* 751 * If the frequencies are not known, PIT is required for both TSC 752 * and apic timer calibration. 753 */ 754 if (!tsc_khz || !cpu_khz) 755 return true; 756 757 /* Is there an APIC at all or is it disabled? */ 758 if (!boot_cpu_has(X86_FEATURE_APIC) || apic_is_disabled) 759 return true; 760 761 /* 762 * If interrupt delivery mode is legacy PIC or virtual wire without 763 * configuration, the local APIC timer won't be set up. Make sure 764 * that the PIT is initialized. 765 */ 766 if (apic_intr_mode == APIC_PIC || 767 apic_intr_mode == APIC_VIRTUAL_WIRE_NO_CONFIG) 768 return true; 769 770 /* Virt guests may lack ARAT, but still have DEADLINE */ 771 if (!boot_cpu_has(X86_FEATURE_ARAT)) 772 return true; 773 774 /* Deadline timer is based on TSC so no further PIT action required */ 775 if (boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) 776 return false; 777 778 /* APIC timer disabled? */ 779 if (disable_apic_timer) 780 return true; 781 /* 782 * The APIC timer frequency is known already, no PIT calibration 783 * required. If unknown, let the PIT be initialized. 784 */ 785 return lapic_timer_period == 0; 786 } 787 788 static int __init calibrate_APIC_clock(void) 789 { 790 struct clock_event_device *levt = this_cpu_ptr(&lapic_events); 791 u64 tsc_perj = 0, tsc_start = 0; 792 unsigned long jif_start; 793 unsigned long deltaj; 794 long delta, deltatsc; 795 int pm_referenced = 0; 796 797 if (boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) 798 return 0; 799 800 /* 801 * Check if lapic timer has already been calibrated by platform 802 * specific routine, such as tsc calibration code. If so just fill 803 * in the clockevent structure and return. 804 */ 805 if (!lapic_init_clockevent()) { 806 apic_pr_verbose("lapic timer already calibrated %d\n", lapic_timer_period); 807 /* 808 * Direct calibration methods must have an always running 809 * local APIC timer, no need for broadcast timer. 810 */ 811 lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY; 812 return 0; 813 } 814 815 apic_pr_verbose("Using local APIC timer interrupts. Calibrating APIC timer ...\n"); 816 817 /* 818 * There are platforms w/o global clockevent devices. Instead of 819 * making the calibration conditional on that, use a polling based 820 * approach everywhere. 821 */ 822 local_irq_disable(); 823 824 /* 825 * Setup the APIC counter to maximum. There is no way the lapic 826 * can underflow in the 100ms detection time frame 827 */ 828 __setup_APIC_LVTT(0xffffffff, 0, 0); 829 830 /* 831 * Methods to terminate the calibration loop: 832 * 1) Global clockevent if available (jiffies) 833 * 2) TSC if available and frequency is known 834 */ 835 jif_start = READ_ONCE(jiffies); 836 837 if (tsc_khz) { 838 tsc_start = rdtsc(); 839 tsc_perj = div_u64((u64)tsc_khz * 1000, HZ); 840 } 841 842 /* 843 * Enable interrupts so the tick can fire, if a global 844 * clockevent device is available 845 */ 846 local_irq_enable(); 847 848 while (lapic_cal_loops <= LAPIC_CAL_LOOPS) { 849 /* Wait for a tick to elapse */ 850 while (1) { 851 if (tsc_khz) { 852 u64 tsc_now = rdtsc(); 853 if ((tsc_now - tsc_start) >= tsc_perj) { 854 tsc_start += tsc_perj; 855 break; 856 } 857 } else { 858 unsigned long jif_now = READ_ONCE(jiffies); 859 860 if (time_after(jif_now, jif_start)) { 861 jif_start = jif_now; 862 break; 863 } 864 } 865 cpu_relax(); 866 } 867 868 /* Invoke the calibration routine */ 869 local_irq_disable(); 870 lapic_cal_handler(NULL); 871 local_irq_enable(); 872 } 873 874 local_irq_disable(); 875 876 /* Build delta t1-t2 as apic timer counts down */ 877 delta = lapic_cal_t1 - lapic_cal_t2; 878 apic_pr_verbose("... lapic delta = %ld\n", delta); 879 880 deltatsc = (long)(lapic_cal_tsc2 - lapic_cal_tsc1); 881 882 /* we trust the PM based calibration if possible */ 883 pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1, 884 &delta, &deltatsc); 885 886 lapic_timer_period = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS; 887 lapic_init_clockevent(); 888 889 apic_pr_verbose("..... delta %ld\n", delta); 890 apic_pr_verbose("..... mult: %u\n", lapic_clockevent.mult); 891 apic_pr_verbose("..... calibration result: %u\n", lapic_timer_period); 892 893 if (boot_cpu_has(X86_FEATURE_TSC)) { 894 apic_pr_verbose("..... CPU clock speed is %ld.%04ld MHz.\n", 895 (deltatsc / LAPIC_CAL_LOOPS) / (1000000 / HZ), 896 (deltatsc / LAPIC_CAL_LOOPS) % (1000000 / HZ)); 897 } 898 899 apic_pr_verbose("..... host bus clock speed is %u.%04u MHz.\n", 900 lapic_timer_period / (1000000 / HZ), 901 lapic_timer_period % (1000000 / HZ)); 902 903 /* 904 * Do a sanity check on the APIC calibration result 905 */ 906 if (lapic_timer_period < (1000000 / HZ)) { 907 local_irq_enable(); 908 pr_warn("APIC frequency too slow, disabling apic timer\n"); 909 return -1; 910 } 911 912 levt->features &= ~CLOCK_EVT_FEAT_DUMMY; 913 914 /* 915 * PM timer calibration failed or not turned on so lets try APIC 916 * timer based calibration, if a global clockevent device is 917 * available. 918 */ 919 if (!pm_referenced && global_clock_event) { 920 apic_pr_verbose("... verify APIC timer\n"); 921 922 /* 923 * Setup the apic timer manually 924 */ 925 levt->event_handler = lapic_cal_handler; 926 lapic_timer_set_periodic(levt); 927 lapic_cal_loops = -1; 928 929 /* Let the interrupts run */ 930 local_irq_enable(); 931 932 while (lapic_cal_loops <= LAPIC_CAL_LOOPS) 933 cpu_relax(); 934 935 /* Stop the lapic timer */ 936 local_irq_disable(); 937 lapic_timer_shutdown(levt); 938 939 /* Jiffies delta */ 940 deltaj = lapic_cal_j2 - lapic_cal_j1; 941 apic_pr_verbose("... jiffies delta = %lu\n", deltaj); 942 943 /* Check, if the jiffies result is consistent */ 944 if (deltaj >= LAPIC_CAL_LOOPS-2 && deltaj <= LAPIC_CAL_LOOPS+2) 945 apic_pr_verbose("... jiffies result ok\n"); 946 else 947 levt->features |= CLOCK_EVT_FEAT_DUMMY; 948 } 949 local_irq_enable(); 950 951 if (levt->features & CLOCK_EVT_FEAT_DUMMY) { 952 pr_warn("APIC timer disabled due to verification failure\n"); 953 return -1; 954 } 955 956 return 0; 957 } 958 959 /* 960 * Setup the boot APIC 961 * 962 * Calibrate and verify the result. 963 */ 964 void __init setup_boot_APIC_clock(void) 965 { 966 /* 967 * The local apic timer can be disabled via the kernel 968 * commandline or from the CPU detection code. Register the lapic 969 * timer as a dummy clock event source on SMP systems, so the 970 * broadcast mechanism is used. On UP systems simply ignore it. 971 */ 972 if (disable_apic_timer) { 973 pr_info("Disabling APIC timer\n"); 974 /* No broadcast on UP ! */ 975 if (num_possible_cpus() > 1) { 976 lapic_clockevent.mult = 1; 977 setup_APIC_timer(); 978 } 979 return; 980 } 981 982 if (calibrate_APIC_clock()) { 983 /* No broadcast on UP ! */ 984 if (num_possible_cpus() > 1) 985 setup_APIC_timer(); 986 return; 987 } 988 989 /* 990 * If nmi_watchdog is set to IO_APIC, we need the 991 * PIT/HPET going. Otherwise register lapic as a dummy 992 * device. 993 */ 994 lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY; 995 996 /* Setup the lapic or request the broadcast */ 997 setup_APIC_timer(); 998 amd_e400_c1e_apic_setup(); 999 } 1000 1001 void setup_secondary_APIC_clock(void) 1002 { 1003 setup_APIC_timer(); 1004 amd_e400_c1e_apic_setup(); 1005 } 1006 1007 /* 1008 * The guts of the apic timer interrupt 1009 */ 1010 static void local_apic_timer_interrupt(void) 1011 { 1012 struct clock_event_device *evt = this_cpu_ptr(&lapic_events); 1013 1014 /* 1015 * Normally we should not be here till LAPIC has been initialized but 1016 * in some cases like kdump, its possible that there is a pending LAPIC 1017 * timer interrupt from previous kernel's context and is delivered in 1018 * new kernel the moment interrupts are enabled. 1019 * 1020 * Interrupts are enabled early and LAPIC is setup much later, hence 1021 * its possible that when we get here evt->event_handler is NULL. 1022 * Check for event_handler being NULL and discard the interrupt as 1023 * spurious. 1024 */ 1025 if (!evt->event_handler) { 1026 pr_warn("Spurious LAPIC timer interrupt on cpu %d\n", 1027 smp_processor_id()); 1028 /* Switch it off */ 1029 lapic_timer_shutdown(evt); 1030 return; 1031 } 1032 1033 /* 1034 * the NMI deadlock-detector uses this. 1035 */ 1036 inc_irq_stat(apic_timer_irqs); 1037 1038 evt->event_handler(evt); 1039 } 1040 1041 /* 1042 * Local APIC timer interrupt. This is the most natural way for doing 1043 * local interrupts, but local timer interrupts can be emulated by 1044 * broadcast interrupts too. [in case the hw doesn't support APIC timers] 1045 * 1046 * [ if a single-CPU system runs an SMP kernel then we call the local 1047 * interrupt as well. Thus we cannot inline the local irq ... ] 1048 */ 1049 DEFINE_IDTENTRY_SYSVEC(sysvec_apic_timer_interrupt) 1050 { 1051 struct pt_regs *old_regs = set_irq_regs(regs); 1052 1053 apic_eoi(); 1054 trace_local_timer_entry(LOCAL_TIMER_VECTOR); 1055 local_apic_timer_interrupt(); 1056 trace_local_timer_exit(LOCAL_TIMER_VECTOR); 1057 1058 set_irq_regs(old_regs); 1059 } 1060 1061 /* 1062 * Local APIC start and shutdown 1063 */ 1064 1065 /** 1066 * clear_local_APIC - shutdown the local APIC 1067 * 1068 * This is called, when a CPU is disabled and before rebooting, so the state of 1069 * the local APIC has no dangling leftovers. Also used to cleanout any BIOS 1070 * leftovers during boot. 1071 */ 1072 void clear_local_APIC(void) 1073 { 1074 int maxlvt; 1075 u32 v; 1076 1077 if (!apic_accessible()) 1078 return; 1079 1080 maxlvt = lapic_get_maxlvt(); 1081 /* 1082 * Masking an LVT entry can trigger a local APIC error 1083 * if the vector is zero. Mask LVTERR first to prevent this. 1084 */ 1085 if (maxlvt >= 3) { 1086 v = ERROR_APIC_VECTOR; /* any non-zero vector will do */ 1087 apic_write(APIC_LVTERR, v | APIC_LVT_MASKED); 1088 } 1089 /* 1090 * Careful: we have to set masks only first to deassert 1091 * any level-triggered sources. 1092 */ 1093 v = apic_read(APIC_LVTT); 1094 apic_write(APIC_LVTT, v | APIC_LVT_MASKED); 1095 v = apic_read(APIC_LVT0); 1096 apic_write(APIC_LVT0, v | APIC_LVT_MASKED); 1097 v = apic_read(APIC_LVT1); 1098 apic_write(APIC_LVT1, v | APIC_LVT_MASKED); 1099 if (maxlvt >= 4) { 1100 v = apic_read(APIC_LVTPC); 1101 apic_write(APIC_LVTPC, v | APIC_LVT_MASKED); 1102 } 1103 1104 /* lets not touch this if we didn't frob it */ 1105 #ifdef CONFIG_X86_THERMAL_VECTOR 1106 if (maxlvt >= 5) { 1107 v = apic_read(APIC_LVTTHMR); 1108 apic_write(APIC_LVTTHMR, v | APIC_LVT_MASKED); 1109 } 1110 #endif 1111 #ifdef CONFIG_X86_MCE_INTEL 1112 if (maxlvt >= 6) { 1113 v = apic_read(APIC_LVTCMCI); 1114 if (!(v & APIC_LVT_MASKED)) 1115 apic_write(APIC_LVTCMCI, v | APIC_LVT_MASKED); 1116 } 1117 #endif 1118 1119 /* 1120 * Clean APIC state for other OSs: 1121 */ 1122 apic_write(APIC_LVTT, APIC_LVT_MASKED); 1123 apic_write(APIC_LVT0, APIC_LVT_MASKED); 1124 apic_write(APIC_LVT1, APIC_LVT_MASKED); 1125 if (maxlvt >= 3) 1126 apic_write(APIC_LVTERR, APIC_LVT_MASKED); 1127 if (maxlvt >= 4) 1128 apic_write(APIC_LVTPC, APIC_LVT_MASKED); 1129 1130 /* Integrated APIC (!82489DX) ? */ 1131 if (lapic_is_integrated()) { 1132 if (maxlvt > 3) 1133 /* Clear ESR due to Pentium errata 3AP and 11AP */ 1134 apic_write(APIC_ESR, 0); 1135 apic_read(APIC_ESR); 1136 } 1137 } 1138 1139 /** 1140 * apic_soft_disable - Clears and software disables the local APIC on hotplug 1141 * 1142 * Contrary to disable_local_APIC() this does not touch the enable bit in 1143 * MSR_IA32_APICBASE. Clearing that bit on systems based on the 3 wire APIC 1144 * bus would require a hardware reset as the APIC would lose track of bus 1145 * arbitration. On systems with FSB delivery APICBASE could be disabled, 1146 * but it has to be guaranteed that no interrupt is sent to the APIC while 1147 * in that state and it's not clear from the SDM whether it still responds 1148 * to INIT/SIPI messages. Stay on the safe side and use software disable. 1149 */ 1150 void apic_soft_disable(void) 1151 { 1152 u32 value; 1153 1154 clear_local_APIC(); 1155 1156 /* Soft disable APIC (implies clearing of registers for 82489DX!). */ 1157 value = apic_read(APIC_SPIV); 1158 value &= ~APIC_SPIV_APIC_ENABLED; 1159 apic_write(APIC_SPIV, value); 1160 } 1161 1162 /** 1163 * disable_local_APIC - clear and disable the local APIC 1164 */ 1165 void disable_local_APIC(void) 1166 { 1167 if (!apic_accessible()) 1168 return; 1169 1170 apic_soft_disable(); 1171 1172 #ifdef CONFIG_X86_32 1173 /* 1174 * When LAPIC was disabled by the BIOS and enabled by the kernel, 1175 * restore the disabled state. 1176 */ 1177 if (enabled_via_apicbase) { 1178 unsigned int l, h; 1179 1180 rdmsr(MSR_IA32_APICBASE, l, h); 1181 l &= ~MSR_IA32_APICBASE_ENABLE; 1182 wrmsr(MSR_IA32_APICBASE, l, h); 1183 } 1184 #endif 1185 } 1186 1187 /* 1188 * If Linux enabled the LAPIC against the BIOS default disable it down before 1189 * re-entering the BIOS on shutdown. Otherwise the BIOS may get confused and 1190 * not power-off. Additionally clear all LVT entries before disable_local_APIC 1191 * for the case where Linux didn't enable the LAPIC. 1192 */ 1193 void lapic_shutdown(void) 1194 { 1195 unsigned long flags; 1196 1197 if (!boot_cpu_has(X86_FEATURE_APIC) && !apic_from_smp_config()) 1198 return; 1199 1200 local_irq_save(flags); 1201 1202 #ifdef CONFIG_X86_32 1203 if (!enabled_via_apicbase) 1204 clear_local_APIC(); 1205 else 1206 #endif 1207 disable_local_APIC(); 1208 1209 1210 local_irq_restore(flags); 1211 } 1212 1213 /** 1214 * sync_Arb_IDs - synchronize APIC bus arbitration IDs 1215 */ 1216 void __init sync_Arb_IDs(void) 1217 { 1218 /* 1219 * Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 And not 1220 * needed on AMD. 1221 */ 1222 if (modern_apic() || boot_cpu_data.x86_vendor == X86_VENDOR_AMD) 1223 return; 1224 1225 /* 1226 * Wait for idle. 1227 */ 1228 apic_wait_icr_idle(); 1229 1230 apic_pr_debug("Synchronizing Arb IDs.\n"); 1231 apic_write(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG | APIC_DM_INIT); 1232 } 1233 1234 enum apic_intr_mode_id apic_intr_mode __ro_after_init; 1235 1236 static int __init __apic_intr_mode_select(void) 1237 { 1238 /* Check kernel option */ 1239 if (apic_is_disabled) { 1240 pr_info("APIC disabled via kernel command line\n"); 1241 return APIC_PIC; 1242 } 1243 1244 /* Check BIOS */ 1245 #ifdef CONFIG_X86_64 1246 /* On 64-bit, the APIC must be integrated, Check local APIC only */ 1247 if (!boot_cpu_has(X86_FEATURE_APIC)) { 1248 apic_is_disabled = true; 1249 pr_info("APIC disabled by BIOS\n"); 1250 return APIC_PIC; 1251 } 1252 #else 1253 /* On 32-bit, the APIC may be integrated APIC or 82489DX */ 1254 1255 /* Neither 82489DX nor integrated APIC ? */ 1256 if (!boot_cpu_has(X86_FEATURE_APIC) && !smp_found_config) { 1257 apic_is_disabled = true; 1258 return APIC_PIC; 1259 } 1260 1261 /* If the BIOS pretends there is an integrated APIC ? */ 1262 if (!boot_cpu_has(X86_FEATURE_APIC) && 1263 APIC_INTEGRATED(boot_cpu_apic_version)) { 1264 apic_is_disabled = true; 1265 pr_err(FW_BUG "Local APIC not detected, force emulation\n"); 1266 return APIC_PIC; 1267 } 1268 #endif 1269 1270 /* Check MP table or ACPI MADT configuration */ 1271 if (!smp_found_config) { 1272 disable_ioapic_support(); 1273 if (!acpi_lapic) { 1274 pr_info("APIC: ACPI MADT or MP tables are not detected\n"); 1275 return APIC_VIRTUAL_WIRE_NO_CONFIG; 1276 } 1277 return APIC_VIRTUAL_WIRE; 1278 } 1279 1280 #ifdef CONFIG_SMP 1281 /* If SMP should be disabled, then really disable it! */ 1282 if (!setup_max_cpus) { 1283 pr_info("APIC: SMP mode deactivated\n"); 1284 return APIC_SYMMETRIC_IO_NO_ROUTING; 1285 } 1286 #endif 1287 1288 return APIC_SYMMETRIC_IO; 1289 } 1290 1291 /* Select the interrupt delivery mode for the BSP */ 1292 void __init apic_intr_mode_select(void) 1293 { 1294 apic_intr_mode = __apic_intr_mode_select(); 1295 } 1296 1297 /* 1298 * An initial setup of the virtual wire mode. 1299 */ 1300 void __init init_bsp_APIC(void) 1301 { 1302 unsigned int value; 1303 1304 /* 1305 * Don't do the setup now if we have a SMP BIOS as the 1306 * through-I/O-APIC virtual wire mode might be active. 1307 */ 1308 if (smp_found_config || !boot_cpu_has(X86_FEATURE_APIC)) 1309 return; 1310 1311 /* 1312 * Do not trust the local APIC being empty at bootup. 1313 */ 1314 clear_local_APIC(); 1315 1316 /* 1317 * Enable APIC. 1318 */ 1319 value = apic_read(APIC_SPIV); 1320 value &= ~APIC_VECTOR_MASK; 1321 value |= APIC_SPIV_APIC_ENABLED; 1322 1323 #ifdef CONFIG_X86_32 1324 /* This bit is reserved on P4/Xeon and should be cleared */ 1325 if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && 1326 (boot_cpu_data.x86 == 15)) 1327 value &= ~APIC_SPIV_FOCUS_DISABLED; 1328 else 1329 #endif 1330 value |= APIC_SPIV_FOCUS_DISABLED; 1331 value |= SPURIOUS_APIC_VECTOR; 1332 apic_write(APIC_SPIV, value); 1333 1334 /* 1335 * Set up the virtual wire mode. 1336 */ 1337 apic_write(APIC_LVT0, APIC_DM_EXTINT); 1338 value = APIC_DM_NMI; 1339 if (!lapic_is_integrated()) /* 82489DX */ 1340 value |= APIC_LVT_LEVEL_TRIGGER; 1341 if (apic_extnmi == APIC_EXTNMI_NONE) 1342 value |= APIC_LVT_MASKED; 1343 apic_write(APIC_LVT1, value); 1344 } 1345 1346 static void __init apic_bsp_setup(bool upmode); 1347 1348 /* Init the interrupt delivery mode for the BSP */ 1349 void __init apic_intr_mode_init(void) 1350 { 1351 bool upmode = IS_ENABLED(CONFIG_UP_LATE_INIT); 1352 1353 switch (apic_intr_mode) { 1354 case APIC_PIC: 1355 pr_info("APIC: Keep in PIC mode(8259)\n"); 1356 return; 1357 case APIC_VIRTUAL_WIRE: 1358 pr_info("APIC: Switch to virtual wire mode setup\n"); 1359 break; 1360 case APIC_VIRTUAL_WIRE_NO_CONFIG: 1361 pr_info("APIC: Switch to virtual wire mode setup with no configuration\n"); 1362 upmode = true; 1363 break; 1364 case APIC_SYMMETRIC_IO: 1365 pr_info("APIC: Switch to symmetric I/O mode setup\n"); 1366 break; 1367 case APIC_SYMMETRIC_IO_NO_ROUTING: 1368 pr_info("APIC: Switch to symmetric I/O mode setup in no SMP routine\n"); 1369 break; 1370 } 1371 1372 x86_64_probe_apic(); 1373 1374 if (x86_platform.apic_post_init) 1375 x86_platform.apic_post_init(); 1376 1377 apic_bsp_setup(upmode); 1378 } 1379 1380 static void lapic_setup_esr(void) 1381 { 1382 unsigned int oldvalue, value, maxlvt; 1383 1384 if (!lapic_is_integrated()) { 1385 pr_info("No ESR for 82489DX.\n"); 1386 return; 1387 } 1388 1389 if (apic->disable_esr) { 1390 /* 1391 * Something untraceable is creating bad interrupts on 1392 * secondary quads ... for the moment, just leave the 1393 * ESR disabled - we can't do anything useful with the 1394 * errors anyway - mbligh 1395 */ 1396 pr_info("Leaving ESR disabled.\n"); 1397 return; 1398 } 1399 1400 maxlvt = lapic_get_maxlvt(); 1401 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ 1402 apic_write(APIC_ESR, 0); 1403 oldvalue = apic_read(APIC_ESR); 1404 1405 /* enables sending errors */ 1406 value = ERROR_APIC_VECTOR; 1407 apic_write(APIC_LVTERR, value); 1408 1409 /* 1410 * spec says clear errors after enabling vector. 1411 */ 1412 if (maxlvt > 3) 1413 apic_write(APIC_ESR, 0); 1414 value = apic_read(APIC_ESR); 1415 if (value != oldvalue) { 1416 apic_pr_verbose("ESR value before enabling vector: 0x%08x after: 0x%08x\n", 1417 oldvalue, value); 1418 } 1419 } 1420 1421 #define APIC_IR_REGS APIC_ISR_NR 1422 #define APIC_IR_BITS (APIC_IR_REGS * 32) 1423 #define APIC_IR_MAPSIZE (APIC_IR_BITS / BITS_PER_LONG) 1424 1425 union apic_ir { 1426 unsigned long map[APIC_IR_MAPSIZE]; 1427 u32 regs[APIC_IR_REGS]; 1428 }; 1429 1430 static bool apic_check_and_ack(union apic_ir *irr, union apic_ir *isr) 1431 { 1432 int i, bit; 1433 1434 /* Read the IRRs */ 1435 for (i = 0; i < APIC_IR_REGS; i++) 1436 irr->regs[i] = apic_read(APIC_IRR + i * 0x10); 1437 1438 /* Read the ISRs */ 1439 for (i = 0; i < APIC_IR_REGS; i++) 1440 isr->regs[i] = apic_read(APIC_ISR + i * 0x10); 1441 1442 /* 1443 * If the ISR map is not empty. ACK the APIC and run another round 1444 * to verify whether a pending IRR has been unblocked and turned 1445 * into a ISR. 1446 */ 1447 if (!bitmap_empty(isr->map, APIC_IR_BITS)) { 1448 /* 1449 * There can be multiple ISR bits set when a high priority 1450 * interrupt preempted a lower priority one. Issue an ACK 1451 * per set bit. 1452 */ 1453 for_each_set_bit(bit, isr->map, APIC_IR_BITS) 1454 apic_eoi(); 1455 return true; 1456 } 1457 1458 return !bitmap_empty(irr->map, APIC_IR_BITS); 1459 } 1460 1461 /* 1462 * After a crash, we no longer service the interrupts and a pending 1463 * interrupt from previous kernel might still have ISR bit set. 1464 * 1465 * Most probably by now the CPU has serviced that pending interrupt and it 1466 * might not have done the apic_eoi() because it thought, interrupt 1467 * came from i8259 as ExtInt. LAPIC did not get EOI so it does not clear 1468 * the ISR bit and cpu thinks it has already serviced the interrupt. Hence 1469 * a vector might get locked. It was noticed for timer irq (vector 1470 * 0x31). Issue an extra EOI to clear ISR. 1471 * 1472 * If there are pending IRR bits they turn into ISR bits after a higher 1473 * priority ISR bit has been acked. 1474 */ 1475 static void apic_pending_intr_clear(void) 1476 { 1477 union apic_ir irr, isr; 1478 unsigned int i; 1479 1480 /* 512 loops are way oversized and give the APIC a chance to obey. */ 1481 for (i = 0; i < 512; i++) { 1482 if (!apic_check_and_ack(&irr, &isr)) 1483 return; 1484 } 1485 /* Dump the IRR/ISR content if that failed */ 1486 pr_warn("APIC: Stale IRR: %256pb ISR: %256pb\n", irr.map, isr.map); 1487 } 1488 1489 /** 1490 * setup_local_APIC - setup the local APIC 1491 * 1492 * Used to setup local APIC while initializing BSP or bringing up APs. 1493 * Always called with preemption disabled. 1494 */ 1495 static void setup_local_APIC(void) 1496 { 1497 int cpu = smp_processor_id(); 1498 unsigned int value; 1499 1500 if (apic_is_disabled) { 1501 disable_ioapic_support(); 1502 return; 1503 } 1504 1505 /* 1506 * If this comes from kexec/kcrash the APIC might be enabled in 1507 * SPIV. Soft disable it before doing further initialization. 1508 */ 1509 value = apic_read(APIC_SPIV); 1510 value &= ~APIC_SPIV_APIC_ENABLED; 1511 apic_write(APIC_SPIV, value); 1512 1513 #ifdef CONFIG_X86_32 1514 /* Pound the ESR really hard over the head with a big hammer - mbligh */ 1515 if (lapic_is_integrated() && apic->disable_esr) { 1516 apic_write(APIC_ESR, 0); 1517 apic_write(APIC_ESR, 0); 1518 apic_write(APIC_ESR, 0); 1519 apic_write(APIC_ESR, 0); 1520 } 1521 #endif 1522 /* 1523 * Intel recommends to set DFR, LDR and TPR before enabling 1524 * an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel 1525 * document number 292116). 1526 * 1527 * Except for APICs which operate in physical destination mode. 1528 */ 1529 if (apic->init_apic_ldr) 1530 apic->init_apic_ldr(); 1531 1532 /* 1533 * Set Task Priority to 'accept all except vectors 0-31'. An APIC 1534 * vector in the 16-31 range could be delivered if TPR == 0, but we 1535 * would think it's an exception and terrible things will happen. We 1536 * never change this later on. 1537 */ 1538 value = apic_read(APIC_TASKPRI); 1539 value &= ~APIC_TPRI_MASK; 1540 value |= 0x10; 1541 apic_write(APIC_TASKPRI, value); 1542 1543 /* Clear eventually stale ISR/IRR bits */ 1544 apic_pending_intr_clear(); 1545 1546 /* 1547 * Now that we are all set up, enable the APIC 1548 */ 1549 value = apic_read(APIC_SPIV); 1550 value &= ~APIC_VECTOR_MASK; 1551 /* 1552 * Enable APIC 1553 */ 1554 value |= APIC_SPIV_APIC_ENABLED; 1555 1556 #ifdef CONFIG_X86_32 1557 /* 1558 * Some unknown Intel IO/APIC (or APIC) errata is biting us with 1559 * certain networking cards. If high frequency interrupts are 1560 * happening on a particular IOAPIC pin, plus the IOAPIC routing 1561 * entry is masked/unmasked at a high rate as well then sooner or 1562 * later IOAPIC line gets 'stuck', no more interrupts are received 1563 * from the device. If focus CPU is disabled then the hang goes 1564 * away, oh well :-( 1565 * 1566 * [ This bug can be reproduced easily with a level-triggered 1567 * PCI Ne2000 networking cards and PII/PIII processors, dual 1568 * BX chipset. ] 1569 */ 1570 /* 1571 * Actually disabling the focus CPU check just makes the hang less 1572 * frequent as it makes the interrupt distribution model be more 1573 * like LRU than MRU (the short-term load is more even across CPUs). 1574 */ 1575 1576 /* 1577 * - enable focus processor (bit==0) 1578 * - 64bit mode always use processor focus 1579 * so no need to set it 1580 */ 1581 value &= ~APIC_SPIV_FOCUS_DISABLED; 1582 #endif 1583 1584 /* 1585 * Set spurious IRQ vector 1586 */ 1587 value |= SPURIOUS_APIC_VECTOR; 1588 apic_write(APIC_SPIV, value); 1589 1590 perf_events_lapic_init(); 1591 1592 /* 1593 * Set up LVT0, LVT1: 1594 * 1595 * set up through-local-APIC on the boot CPU's LINT0. This is not 1596 * strictly necessary in pure symmetric-IO mode, but sometimes 1597 * we delegate interrupts to the 8259A. 1598 */ 1599 /* 1600 * TODO: set up through-local-APIC from through-I/O-APIC? --macro 1601 */ 1602 value = apic_read(APIC_LVT0) & APIC_LVT_MASKED; 1603 if (!cpu && (pic_mode || !value || ioapic_is_disabled)) { 1604 value = APIC_DM_EXTINT; 1605 apic_pr_verbose("Enabled ExtINT on CPU#%d\n", cpu); 1606 } else { 1607 value = APIC_DM_EXTINT | APIC_LVT_MASKED; 1608 apic_pr_verbose("Masked ExtINT on CPU#%d\n", cpu); 1609 } 1610 apic_write(APIC_LVT0, value); 1611 1612 /* 1613 * Only the BSP sees the LINT1 NMI signal by default. This can be 1614 * modified by apic_extnmi= boot option. 1615 */ 1616 if ((!cpu && apic_extnmi != APIC_EXTNMI_NONE) || 1617 apic_extnmi == APIC_EXTNMI_ALL) 1618 value = APIC_DM_NMI; 1619 else 1620 value = APIC_DM_NMI | APIC_LVT_MASKED; 1621 1622 /* Is 82489DX ? */ 1623 if (!lapic_is_integrated()) 1624 value |= APIC_LVT_LEVEL_TRIGGER; 1625 apic_write(APIC_LVT1, value); 1626 1627 #ifdef CONFIG_X86_MCE_INTEL 1628 /* Recheck CMCI information after local APIC is up on CPU #0 */ 1629 if (!cpu) 1630 cmci_recheck(); 1631 #endif 1632 } 1633 1634 static void end_local_APIC_setup(void) 1635 { 1636 lapic_setup_esr(); 1637 1638 #ifdef CONFIG_X86_32 1639 { 1640 unsigned int value; 1641 /* Disable the local apic timer */ 1642 value = apic_read(APIC_LVTT); 1643 value |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR); 1644 apic_write(APIC_LVTT, value); 1645 } 1646 #endif 1647 1648 apic_pm_activate(); 1649 } 1650 1651 /* 1652 * APIC setup function for application processors. Called from smpboot.c 1653 */ 1654 void apic_ap_setup(void) 1655 { 1656 setup_local_APIC(); 1657 end_local_APIC_setup(); 1658 } 1659 1660 static __init void apic_read_boot_cpu_id(bool x2apic) 1661 { 1662 /* 1663 * This can be invoked from check_x2apic() before the APIC has been 1664 * selected. But that code knows for sure that the BIOS enabled 1665 * X2APIC. 1666 */ 1667 if (x2apic) { 1668 boot_cpu_physical_apicid = native_apic_msr_read(APIC_ID); 1669 boot_cpu_apic_version = GET_APIC_VERSION(native_apic_msr_read(APIC_LVR)); 1670 } else { 1671 boot_cpu_physical_apicid = read_apic_id(); 1672 boot_cpu_apic_version = GET_APIC_VERSION(apic_read(APIC_LVR)); 1673 } 1674 topology_register_boot_apic(boot_cpu_physical_apicid); 1675 } 1676 1677 #ifdef CONFIG_X86_X2APIC 1678 int x2apic_mode; 1679 EXPORT_SYMBOL_GPL(x2apic_mode); 1680 1681 enum { 1682 X2APIC_OFF, 1683 X2APIC_DISABLED, 1684 /* All states below here have X2APIC enabled */ 1685 X2APIC_ON, 1686 X2APIC_ON_LOCKED 1687 }; 1688 static int x2apic_state; 1689 1690 static bool x2apic_hw_locked(void) 1691 { 1692 u64 x86_arch_cap_msr; 1693 u64 msr; 1694 1695 x86_arch_cap_msr = x86_read_arch_cap_msr(); 1696 if (x86_arch_cap_msr & ARCH_CAP_XAPIC_DISABLE) { 1697 rdmsrl(MSR_IA32_XAPIC_DISABLE_STATUS, msr); 1698 return (msr & LEGACY_XAPIC_DISABLED); 1699 } 1700 return false; 1701 } 1702 1703 static void __x2apic_disable(void) 1704 { 1705 u64 msr; 1706 1707 if (!boot_cpu_has(X86_FEATURE_APIC)) 1708 return; 1709 1710 rdmsrl(MSR_IA32_APICBASE, msr); 1711 if (!(msr & X2APIC_ENABLE)) 1712 return; 1713 /* Disable xapic and x2apic first and then reenable xapic mode */ 1714 wrmsrl(MSR_IA32_APICBASE, msr & ~(X2APIC_ENABLE | XAPIC_ENABLE)); 1715 wrmsrl(MSR_IA32_APICBASE, msr & ~X2APIC_ENABLE); 1716 printk_once(KERN_INFO "x2apic disabled\n"); 1717 } 1718 1719 static void __x2apic_enable(void) 1720 { 1721 u64 msr; 1722 1723 rdmsrl(MSR_IA32_APICBASE, msr); 1724 if (msr & X2APIC_ENABLE) 1725 return; 1726 wrmsrl(MSR_IA32_APICBASE, msr | X2APIC_ENABLE); 1727 printk_once(KERN_INFO "x2apic enabled\n"); 1728 } 1729 1730 static int __init setup_nox2apic(char *str) 1731 { 1732 if (x2apic_enabled()) { 1733 u32 apicid = native_apic_msr_read(APIC_ID); 1734 1735 if (apicid >= 255) { 1736 pr_warn("Apicid: %08x, cannot enforce nox2apic\n", 1737 apicid); 1738 return 0; 1739 } 1740 if (x2apic_hw_locked()) { 1741 pr_warn("APIC locked in x2apic mode, can't disable\n"); 1742 return 0; 1743 } 1744 pr_warn("x2apic already enabled.\n"); 1745 __x2apic_disable(); 1746 } 1747 setup_clear_cpu_cap(X86_FEATURE_X2APIC); 1748 x2apic_state = X2APIC_DISABLED; 1749 x2apic_mode = 0; 1750 return 0; 1751 } 1752 early_param("nox2apic", setup_nox2apic); 1753 1754 /* Called from cpu_init() to enable x2apic on (secondary) cpus */ 1755 void x2apic_setup(void) 1756 { 1757 /* 1758 * Try to make the AP's APIC state match that of the BSP, but if the 1759 * BSP is unlocked and the AP is locked then there is a state mismatch. 1760 * Warn about the mismatch in case a GP fault occurs due to a locked AP 1761 * trying to be turned off. 1762 */ 1763 if (x2apic_state != X2APIC_ON_LOCKED && x2apic_hw_locked()) 1764 pr_warn("x2apic lock mismatch between BSP and AP.\n"); 1765 /* 1766 * If x2apic is not in ON or LOCKED state, disable it if already enabled 1767 * from BIOS. 1768 */ 1769 if (x2apic_state < X2APIC_ON) { 1770 __x2apic_disable(); 1771 return; 1772 } 1773 __x2apic_enable(); 1774 } 1775 1776 static __init void apic_set_fixmap(bool read_apic); 1777 1778 static __init void x2apic_disable(void) 1779 { 1780 u32 x2apic_id; 1781 1782 if (x2apic_state < X2APIC_ON) 1783 return; 1784 1785 x2apic_id = read_apic_id(); 1786 if (x2apic_id >= 255) 1787 panic("Cannot disable x2apic, id: %08x\n", x2apic_id); 1788 1789 if (x2apic_hw_locked()) { 1790 pr_warn("Cannot disable locked x2apic, id: %08x\n", x2apic_id); 1791 return; 1792 } 1793 1794 __x2apic_disable(); 1795 1796 x2apic_mode = 0; 1797 x2apic_state = X2APIC_DISABLED; 1798 1799 /* 1800 * Don't reread the APIC ID as it was already done from 1801 * check_x2apic() and the APIC driver still is a x2APIC variant, 1802 * which fails to do the read after x2APIC was disabled. 1803 */ 1804 apic_set_fixmap(false); 1805 } 1806 1807 static __init void x2apic_enable(void) 1808 { 1809 if (x2apic_state != X2APIC_OFF) 1810 return; 1811 1812 x2apic_mode = 1; 1813 x2apic_state = X2APIC_ON; 1814 __x2apic_enable(); 1815 } 1816 1817 static __init void try_to_enable_x2apic(int remap_mode) 1818 { 1819 if (x2apic_state == X2APIC_DISABLED) 1820 return; 1821 1822 if (remap_mode != IRQ_REMAP_X2APIC_MODE) { 1823 u32 apic_limit = 255; 1824 1825 /* 1826 * Using X2APIC without IR is not architecturally supported 1827 * on bare metal but may be supported in guests. 1828 */ 1829 if (!x86_init.hyper.x2apic_available()) { 1830 pr_info("x2apic: IRQ remapping doesn't support X2APIC mode\n"); 1831 x2apic_disable(); 1832 return; 1833 } 1834 1835 /* 1836 * If the hypervisor supports extended destination ID in 1837 * MSI, that increases the maximum APIC ID that can be 1838 * used for non-remapped IRQ domains. 1839 */ 1840 if (x86_init.hyper.msi_ext_dest_id()) { 1841 virt_ext_dest_id = 1; 1842 apic_limit = 32767; 1843 } 1844 1845 /* 1846 * Without IR, all CPUs can be addressed by IOAPIC/MSI only 1847 * in physical mode, and CPUs with an APIC ID that cannot 1848 * be addressed must not be brought online. 1849 */ 1850 x2apic_set_max_apicid(apic_limit); 1851 x2apic_phys = 1; 1852 } 1853 x2apic_enable(); 1854 } 1855 1856 void __init check_x2apic(void) 1857 { 1858 if (x2apic_enabled()) { 1859 pr_info("x2apic: enabled by BIOS, switching to x2apic ops\n"); 1860 x2apic_mode = 1; 1861 if (x2apic_hw_locked()) 1862 x2apic_state = X2APIC_ON_LOCKED; 1863 else 1864 x2apic_state = X2APIC_ON; 1865 apic_read_boot_cpu_id(true); 1866 } else if (!boot_cpu_has(X86_FEATURE_X2APIC)) { 1867 x2apic_state = X2APIC_DISABLED; 1868 } 1869 } 1870 #else /* CONFIG_X86_X2APIC */ 1871 void __init check_x2apic(void) 1872 { 1873 if (!apic_is_x2apic_enabled()) 1874 return; 1875 /* 1876 * Checkme: Can we simply turn off x2APIC here instead of disabling the APIC? 1877 */ 1878 pr_err("Kernel does not support x2APIC, please recompile with CONFIG_X86_X2APIC.\n"); 1879 pr_err("Disabling APIC, expect reduced performance and functionality.\n"); 1880 1881 apic_is_disabled = true; 1882 setup_clear_cpu_cap(X86_FEATURE_APIC); 1883 } 1884 1885 static inline void try_to_enable_x2apic(int remap_mode) { } 1886 static inline void __x2apic_enable(void) { } 1887 #endif /* !CONFIG_X86_X2APIC */ 1888 1889 void __init enable_IR_x2apic(void) 1890 { 1891 unsigned long flags; 1892 int ret, ir_stat; 1893 1894 if (ioapic_is_disabled) { 1895 pr_info("Not enabling interrupt remapping due to skipped IO-APIC setup\n"); 1896 return; 1897 } 1898 1899 ir_stat = irq_remapping_prepare(); 1900 if (ir_stat < 0 && !x2apic_supported()) 1901 return; 1902 1903 ret = save_ioapic_entries(); 1904 if (ret) { 1905 pr_info("Saving IO-APIC state failed: %d\n", ret); 1906 return; 1907 } 1908 1909 local_irq_save(flags); 1910 legacy_pic->mask_all(); 1911 mask_ioapic_entries(); 1912 1913 /* If irq_remapping_prepare() succeeded, try to enable it */ 1914 if (ir_stat >= 0) 1915 ir_stat = irq_remapping_enable(); 1916 /* ir_stat contains the remap mode or an error code */ 1917 try_to_enable_x2apic(ir_stat); 1918 1919 if (ir_stat < 0) 1920 restore_ioapic_entries(); 1921 legacy_pic->restore_mask(); 1922 local_irq_restore(flags); 1923 } 1924 1925 #ifdef CONFIG_X86_64 1926 /* 1927 * Detect and enable local APICs on non-SMP boards. 1928 * Original code written by Keir Fraser. 1929 * On AMD64 we trust the BIOS - if it says no APIC it is likely 1930 * not correctly set up (usually the APIC timer won't work etc.) 1931 */ 1932 static bool __init detect_init_APIC(void) 1933 { 1934 if (!boot_cpu_has(X86_FEATURE_APIC)) { 1935 pr_info("No local APIC present\n"); 1936 return false; 1937 } 1938 1939 register_lapic_address(APIC_DEFAULT_PHYS_BASE); 1940 return true; 1941 } 1942 #else 1943 1944 static bool __init apic_verify(unsigned long addr) 1945 { 1946 u32 features, h, l; 1947 1948 /* 1949 * The APIC feature bit should now be enabled 1950 * in `cpuid' 1951 */ 1952 features = cpuid_edx(1); 1953 if (!(features & (1 << X86_FEATURE_APIC))) { 1954 pr_warn("Could not enable APIC!\n"); 1955 return false; 1956 } 1957 set_cpu_cap(&boot_cpu_data, X86_FEATURE_APIC); 1958 1959 /* The BIOS may have set up the APIC at some other address */ 1960 if (boot_cpu_data.x86 >= 6) { 1961 rdmsr(MSR_IA32_APICBASE, l, h); 1962 if (l & MSR_IA32_APICBASE_ENABLE) 1963 addr = l & MSR_IA32_APICBASE_BASE; 1964 } 1965 1966 register_lapic_address(addr); 1967 pr_info("Found and enabled local APIC!\n"); 1968 return true; 1969 } 1970 1971 bool __init apic_force_enable(unsigned long addr) 1972 { 1973 u32 h, l; 1974 1975 if (apic_is_disabled) 1976 return false; 1977 1978 /* 1979 * Some BIOSes disable the local APIC in the APIC_BASE 1980 * MSR. This can only be done in software for Intel P6 or later 1981 * and AMD K7 (Model > 1) or later. 1982 */ 1983 if (boot_cpu_data.x86 >= 6) { 1984 rdmsr(MSR_IA32_APICBASE, l, h); 1985 if (!(l & MSR_IA32_APICBASE_ENABLE)) { 1986 pr_info("Local APIC disabled by BIOS -- reenabling.\n"); 1987 l &= ~MSR_IA32_APICBASE_BASE; 1988 l |= MSR_IA32_APICBASE_ENABLE | addr; 1989 wrmsr(MSR_IA32_APICBASE, l, h); 1990 enabled_via_apicbase = 1; 1991 } 1992 } 1993 return apic_verify(addr); 1994 } 1995 1996 /* 1997 * Detect and initialize APIC 1998 */ 1999 static bool __init detect_init_APIC(void) 2000 { 2001 /* Disabled by kernel option? */ 2002 if (apic_is_disabled) 2003 return false; 2004 2005 switch (boot_cpu_data.x86_vendor) { 2006 case X86_VENDOR_AMD: 2007 if ((boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model > 1) || 2008 (boot_cpu_data.x86 >= 15)) 2009 break; 2010 goto no_apic; 2011 case X86_VENDOR_HYGON: 2012 break; 2013 case X86_VENDOR_INTEL: 2014 if ((boot_cpu_data.x86 == 5 && boot_cpu_has(X86_FEATURE_APIC)) || 2015 boot_cpu_data.x86_vfm >= INTEL_PENTIUM_PRO) 2016 break; 2017 goto no_apic; 2018 default: 2019 goto no_apic; 2020 } 2021 2022 if (!boot_cpu_has(X86_FEATURE_APIC)) { 2023 /* 2024 * Over-ride BIOS and try to enable the local APIC only if 2025 * "lapic" specified. 2026 */ 2027 if (!force_enable_local_apic) { 2028 pr_info("Local APIC disabled by BIOS -- " 2029 "you can enable it with \"lapic\"\n"); 2030 return false; 2031 } 2032 if (!apic_force_enable(APIC_DEFAULT_PHYS_BASE)) 2033 return false; 2034 } else { 2035 if (!apic_verify(APIC_DEFAULT_PHYS_BASE)) 2036 return false; 2037 } 2038 2039 apic_pm_activate(); 2040 2041 return true; 2042 2043 no_apic: 2044 pr_info("No local APIC present or hardware disabled\n"); 2045 return false; 2046 } 2047 #endif 2048 2049 /** 2050 * init_apic_mappings - initialize APIC mappings 2051 */ 2052 void __init init_apic_mappings(void) 2053 { 2054 if (apic_validate_deadline_timer()) 2055 pr_info("TSC deadline timer available\n"); 2056 2057 if (x2apic_mode) 2058 return; 2059 2060 if (!smp_found_config) { 2061 if (!detect_init_APIC()) { 2062 pr_info("APIC: disable apic facility\n"); 2063 apic_disable(); 2064 } 2065 } 2066 } 2067 2068 static __init void apic_set_fixmap(bool read_apic) 2069 { 2070 set_fixmap_nocache(FIX_APIC_BASE, mp_lapic_addr); 2071 apic_mmio_base = APIC_BASE; 2072 apic_pr_verbose("Mapped APIC to %16lx (%16lx)\n", apic_mmio_base, mp_lapic_addr); 2073 if (read_apic) 2074 apic_read_boot_cpu_id(false); 2075 } 2076 2077 void __init register_lapic_address(unsigned long address) 2078 { 2079 /* This should only happen once */ 2080 WARN_ON_ONCE(mp_lapic_addr); 2081 mp_lapic_addr = address; 2082 2083 if (!x2apic_mode) 2084 apic_set_fixmap(true); 2085 } 2086 2087 /* 2088 * Local APIC interrupts 2089 */ 2090 2091 /* 2092 * Common handling code for spurious_interrupt and spurious_vector entry 2093 * points below. No point in allowing the compiler to inline it twice. 2094 */ 2095 static noinline void handle_spurious_interrupt(u8 vector) 2096 { 2097 u32 v; 2098 2099 trace_spurious_apic_entry(vector); 2100 2101 inc_irq_stat(irq_spurious_count); 2102 2103 /* 2104 * If this is a spurious interrupt then do not acknowledge 2105 */ 2106 if (vector == SPURIOUS_APIC_VECTOR) { 2107 /* See SDM vol 3 */ 2108 pr_info("Spurious APIC interrupt (vector 0xFF) on CPU#%d, should never happen.\n", 2109 smp_processor_id()); 2110 goto out; 2111 } 2112 2113 /* 2114 * If it is a vectored one, verify it's set in the ISR. If set, 2115 * acknowledge it. 2116 */ 2117 v = apic_read(APIC_ISR + ((vector & ~0x1f) >> 1)); 2118 if (v & (1 << (vector & 0x1f))) { 2119 pr_info("Spurious interrupt (vector 0x%02x) on CPU#%d. Acked\n", 2120 vector, smp_processor_id()); 2121 apic_eoi(); 2122 } else { 2123 pr_info("Spurious interrupt (vector 0x%02x) on CPU#%d. Not pending!\n", 2124 vector, smp_processor_id()); 2125 } 2126 out: 2127 trace_spurious_apic_exit(vector); 2128 } 2129 2130 /** 2131 * spurious_interrupt - Catch all for interrupts raised on unused vectors 2132 * @regs: Pointer to pt_regs on stack 2133 * @vector: The vector number 2134 * 2135 * This is invoked from ASM entry code to catch all interrupts which 2136 * trigger on an entry which is routed to the common_spurious idtentry 2137 * point. 2138 */ 2139 DEFINE_IDTENTRY_IRQ(spurious_interrupt) 2140 { 2141 handle_spurious_interrupt(vector); 2142 } 2143 2144 DEFINE_IDTENTRY_SYSVEC(sysvec_spurious_apic_interrupt) 2145 { 2146 handle_spurious_interrupt(SPURIOUS_APIC_VECTOR); 2147 } 2148 2149 /* 2150 * This interrupt should never happen with our APIC/SMP architecture 2151 */ 2152 DEFINE_IDTENTRY_SYSVEC(sysvec_error_interrupt) 2153 { 2154 static const char * const error_interrupt_reason[] = { 2155 "Send CS error", /* APIC Error Bit 0 */ 2156 "Receive CS error", /* APIC Error Bit 1 */ 2157 "Send accept error", /* APIC Error Bit 2 */ 2158 "Receive accept error", /* APIC Error Bit 3 */ 2159 "Redirectable IPI", /* APIC Error Bit 4 */ 2160 "Send illegal vector", /* APIC Error Bit 5 */ 2161 "Received illegal vector", /* APIC Error Bit 6 */ 2162 "Illegal register address", /* APIC Error Bit 7 */ 2163 }; 2164 u32 v, i = 0; 2165 2166 trace_error_apic_entry(ERROR_APIC_VECTOR); 2167 2168 /* First tickle the hardware, only then report what went on. -- REW */ 2169 if (lapic_get_maxlvt() > 3) /* Due to the Pentium erratum 3AP. */ 2170 apic_write(APIC_ESR, 0); 2171 v = apic_read(APIC_ESR); 2172 apic_eoi(); 2173 atomic_inc(&irq_err_count); 2174 2175 apic_pr_debug("APIC error on CPU%d: %02x", smp_processor_id(), v); 2176 2177 v &= 0xff; 2178 while (v) { 2179 if (v & 0x1) 2180 apic_pr_debug_cont(" : %s", error_interrupt_reason[i]); 2181 i++; 2182 v >>= 1; 2183 } 2184 2185 apic_pr_debug_cont("\n"); 2186 2187 trace_error_apic_exit(ERROR_APIC_VECTOR); 2188 } 2189 2190 /** 2191 * connect_bsp_APIC - attach the APIC to the interrupt system 2192 */ 2193 static void __init connect_bsp_APIC(void) 2194 { 2195 #ifdef CONFIG_X86_32 2196 if (pic_mode) { 2197 /* 2198 * Do not trust the local APIC being empty at bootup. 2199 */ 2200 clear_local_APIC(); 2201 /* 2202 * PIC mode, enable APIC mode in the IMCR, i.e. connect BSP's 2203 * local APIC to INT and NMI lines. 2204 */ 2205 apic_pr_verbose("Leaving PIC mode, enabling APIC mode.\n"); 2206 imcr_pic_to_apic(); 2207 } 2208 #endif 2209 } 2210 2211 /** 2212 * disconnect_bsp_APIC - detach the APIC from the interrupt system 2213 * @virt_wire_setup: indicates, whether virtual wire mode is selected 2214 * 2215 * Virtual wire mode is necessary to deliver legacy interrupts even when the 2216 * APIC is disabled. 2217 */ 2218 void disconnect_bsp_APIC(int virt_wire_setup) 2219 { 2220 unsigned int value; 2221 2222 #ifdef CONFIG_X86_32 2223 if (pic_mode) { 2224 /* 2225 * Put the board back into PIC mode (has an effect only on 2226 * certain older boards). Note that APIC interrupts, including 2227 * IPIs, won't work beyond this point! The only exception are 2228 * INIT IPIs. 2229 */ 2230 apic_pr_verbose("Disabling APIC mode, entering PIC mode.\n"); 2231 imcr_apic_to_pic(); 2232 return; 2233 } 2234 #endif 2235 2236 /* Go back to Virtual Wire compatibility mode */ 2237 2238 /* For the spurious interrupt use vector F, and enable it */ 2239 value = apic_read(APIC_SPIV); 2240 value &= ~APIC_VECTOR_MASK; 2241 value |= APIC_SPIV_APIC_ENABLED; 2242 value |= 0xf; 2243 apic_write(APIC_SPIV, value); 2244 2245 if (!virt_wire_setup) { 2246 /* 2247 * For LVT0 make it edge triggered, active high, 2248 * external and enabled 2249 */ 2250 value = apic_read(APIC_LVT0); 2251 value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING | 2252 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR | 2253 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED); 2254 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING; 2255 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT); 2256 apic_write(APIC_LVT0, value); 2257 } else { 2258 /* Disable LVT0 */ 2259 apic_write(APIC_LVT0, APIC_LVT_MASKED); 2260 } 2261 2262 /* 2263 * For LVT1 make it edge triggered, active high, 2264 * nmi and enabled 2265 */ 2266 value = apic_read(APIC_LVT1); 2267 value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING | 2268 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR | 2269 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED); 2270 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING; 2271 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI); 2272 apic_write(APIC_LVT1, value); 2273 } 2274 2275 void __irq_msi_compose_msg(struct irq_cfg *cfg, struct msi_msg *msg, 2276 bool dmar) 2277 { 2278 memset(msg, 0, sizeof(*msg)); 2279 2280 msg->arch_addr_lo.base_address = X86_MSI_BASE_ADDRESS_LOW; 2281 msg->arch_addr_lo.dest_mode_logical = apic->dest_mode_logical; 2282 msg->arch_addr_lo.destid_0_7 = cfg->dest_apicid & 0xFF; 2283 2284 msg->arch_data.delivery_mode = APIC_DELIVERY_MODE_FIXED; 2285 msg->arch_data.vector = cfg->vector; 2286 2287 msg->address_hi = X86_MSI_BASE_ADDRESS_HIGH; 2288 /* 2289 * Only the IOMMU itself can use the trick of putting destination 2290 * APIC ID into the high bits of the address. Anything else would 2291 * just be writing to memory if it tried that, and needs IR to 2292 * address APICs which can't be addressed in the normal 32-bit 2293 * address range at 0xFFExxxxx. That is typically just 8 bits, but 2294 * some hypervisors allow the extended destination ID field in bits 2295 * 5-11 to be used, giving support for 15 bits of APIC IDs in total. 2296 */ 2297 if (dmar) 2298 msg->arch_addr_hi.destid_8_31 = cfg->dest_apicid >> 8; 2299 else if (virt_ext_dest_id && cfg->dest_apicid < 0x8000) 2300 msg->arch_addr_lo.virt_destid_8_14 = cfg->dest_apicid >> 8; 2301 else 2302 WARN_ON_ONCE(cfg->dest_apicid > 0xFF); 2303 } 2304 2305 u32 x86_msi_msg_get_destid(struct msi_msg *msg, bool extid) 2306 { 2307 u32 dest = msg->arch_addr_lo.destid_0_7; 2308 2309 if (extid) 2310 dest |= msg->arch_addr_hi.destid_8_31 << 8; 2311 return dest; 2312 } 2313 EXPORT_SYMBOL_GPL(x86_msi_msg_get_destid); 2314 2315 static void __init apic_bsp_up_setup(void) 2316 { 2317 reset_phys_cpu_present_map(boot_cpu_physical_apicid); 2318 } 2319 2320 /** 2321 * apic_bsp_setup - Setup function for local apic and io-apic 2322 * @upmode: Force UP mode (for APIC_init_uniprocessor) 2323 */ 2324 static void __init apic_bsp_setup(bool upmode) 2325 { 2326 connect_bsp_APIC(); 2327 if (upmode) 2328 apic_bsp_up_setup(); 2329 setup_local_APIC(); 2330 2331 enable_IO_APIC(); 2332 end_local_APIC_setup(); 2333 irq_remap_enable_fault_handling(); 2334 setup_IO_APIC(); 2335 lapic_update_legacy_vectors(); 2336 } 2337 2338 #ifdef CONFIG_UP_LATE_INIT 2339 void __init up_late_init(void) 2340 { 2341 if (apic_intr_mode == APIC_PIC) 2342 return; 2343 2344 /* Setup local timer */ 2345 x86_init.timers.setup_percpu_clockev(); 2346 } 2347 #endif 2348 2349 /* 2350 * Power management 2351 */ 2352 #ifdef CONFIG_PM 2353 2354 static struct { 2355 /* 2356 * 'active' is true if the local APIC was enabled by us and 2357 * not the BIOS; this signifies that we are also responsible 2358 * for disabling it before entering apm/acpi suspend 2359 */ 2360 int active; 2361 /* r/w apic fields */ 2362 u32 apic_id; 2363 unsigned int apic_taskpri; 2364 unsigned int apic_ldr; 2365 unsigned int apic_dfr; 2366 unsigned int apic_spiv; 2367 unsigned int apic_lvtt; 2368 unsigned int apic_lvtpc; 2369 unsigned int apic_lvt0; 2370 unsigned int apic_lvt1; 2371 unsigned int apic_lvterr; 2372 unsigned int apic_tmict; 2373 unsigned int apic_tdcr; 2374 unsigned int apic_thmr; 2375 unsigned int apic_cmci; 2376 } apic_pm_state; 2377 2378 static int lapic_suspend(void) 2379 { 2380 unsigned long flags; 2381 int maxlvt; 2382 2383 if (!apic_pm_state.active) 2384 return 0; 2385 2386 maxlvt = lapic_get_maxlvt(); 2387 2388 apic_pm_state.apic_id = apic_read(APIC_ID); 2389 apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI); 2390 apic_pm_state.apic_ldr = apic_read(APIC_LDR); 2391 apic_pm_state.apic_dfr = apic_read(APIC_DFR); 2392 apic_pm_state.apic_spiv = apic_read(APIC_SPIV); 2393 apic_pm_state.apic_lvtt = apic_read(APIC_LVTT); 2394 if (maxlvt >= 4) 2395 apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC); 2396 apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0); 2397 apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1); 2398 apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR); 2399 apic_pm_state.apic_tmict = apic_read(APIC_TMICT); 2400 apic_pm_state.apic_tdcr = apic_read(APIC_TDCR); 2401 #ifdef CONFIG_X86_THERMAL_VECTOR 2402 if (maxlvt >= 5) 2403 apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR); 2404 #endif 2405 #ifdef CONFIG_X86_MCE_INTEL 2406 if (maxlvt >= 6) 2407 apic_pm_state.apic_cmci = apic_read(APIC_LVTCMCI); 2408 #endif 2409 2410 local_irq_save(flags); 2411 2412 /* 2413 * Mask IOAPIC before disabling the local APIC to prevent stale IRR 2414 * entries on some implementations. 2415 */ 2416 mask_ioapic_entries(); 2417 2418 disable_local_APIC(); 2419 2420 irq_remapping_disable(); 2421 2422 local_irq_restore(flags); 2423 return 0; 2424 } 2425 2426 static void lapic_resume(void) 2427 { 2428 unsigned int l, h; 2429 unsigned long flags; 2430 int maxlvt; 2431 2432 if (!apic_pm_state.active) 2433 return; 2434 2435 local_irq_save(flags); 2436 2437 /* 2438 * IO-APIC and PIC have their own resume routines. 2439 * We just mask them here to make sure the interrupt 2440 * subsystem is completely quiet while we enable x2apic 2441 * and interrupt-remapping. 2442 */ 2443 mask_ioapic_entries(); 2444 legacy_pic->mask_all(); 2445 2446 if (x2apic_mode) { 2447 __x2apic_enable(); 2448 } else { 2449 /* 2450 * Make sure the APICBASE points to the right address 2451 * 2452 * FIXME! This will be wrong if we ever support suspend on 2453 * SMP! We'll need to do this as part of the CPU restore! 2454 */ 2455 if (boot_cpu_data.x86 >= 6) { 2456 rdmsr(MSR_IA32_APICBASE, l, h); 2457 l &= ~MSR_IA32_APICBASE_BASE; 2458 l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr; 2459 wrmsr(MSR_IA32_APICBASE, l, h); 2460 } 2461 } 2462 2463 maxlvt = lapic_get_maxlvt(); 2464 apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED); 2465 apic_write(APIC_ID, apic_pm_state.apic_id); 2466 apic_write(APIC_DFR, apic_pm_state.apic_dfr); 2467 apic_write(APIC_LDR, apic_pm_state.apic_ldr); 2468 apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri); 2469 apic_write(APIC_SPIV, apic_pm_state.apic_spiv); 2470 apic_write(APIC_LVT0, apic_pm_state.apic_lvt0); 2471 apic_write(APIC_LVT1, apic_pm_state.apic_lvt1); 2472 #ifdef CONFIG_X86_THERMAL_VECTOR 2473 if (maxlvt >= 5) 2474 apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr); 2475 #endif 2476 #ifdef CONFIG_X86_MCE_INTEL 2477 if (maxlvt >= 6) 2478 apic_write(APIC_LVTCMCI, apic_pm_state.apic_cmci); 2479 #endif 2480 if (maxlvt >= 4) 2481 apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc); 2482 apic_write(APIC_LVTT, apic_pm_state.apic_lvtt); 2483 apic_write(APIC_TDCR, apic_pm_state.apic_tdcr); 2484 apic_write(APIC_TMICT, apic_pm_state.apic_tmict); 2485 apic_write(APIC_ESR, 0); 2486 apic_read(APIC_ESR); 2487 apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr); 2488 apic_write(APIC_ESR, 0); 2489 apic_read(APIC_ESR); 2490 2491 irq_remapping_reenable(x2apic_mode); 2492 2493 local_irq_restore(flags); 2494 } 2495 2496 /* 2497 * This device has no shutdown method - fully functioning local APICs 2498 * are needed on every CPU up until machine_halt/restart/poweroff. 2499 */ 2500 2501 static struct syscore_ops lapic_syscore_ops = { 2502 .resume = lapic_resume, 2503 .suspend = lapic_suspend, 2504 }; 2505 2506 static void apic_pm_activate(void) 2507 { 2508 apic_pm_state.active = 1; 2509 } 2510 2511 static int __init init_lapic_sysfs(void) 2512 { 2513 /* XXX: remove suspend/resume procs if !apic_pm_state.active? */ 2514 if (boot_cpu_has(X86_FEATURE_APIC)) 2515 register_syscore_ops(&lapic_syscore_ops); 2516 2517 return 0; 2518 } 2519 2520 /* local apic needs to resume before other devices access its registers. */ 2521 core_initcall(init_lapic_sysfs); 2522 2523 #else /* CONFIG_PM */ 2524 2525 static void apic_pm_activate(void) { } 2526 2527 #endif /* CONFIG_PM */ 2528 2529 #ifdef CONFIG_X86_64 2530 2531 static int multi_checked; 2532 static int multi; 2533 2534 static int set_multi(const struct dmi_system_id *d) 2535 { 2536 if (multi) 2537 return 0; 2538 pr_info("APIC: %s detected, Multi Chassis\n", d->ident); 2539 multi = 1; 2540 return 0; 2541 } 2542 2543 static const struct dmi_system_id multi_dmi_table[] = { 2544 { 2545 .callback = set_multi, 2546 .ident = "IBM System Summit2", 2547 .matches = { 2548 DMI_MATCH(DMI_SYS_VENDOR, "IBM"), 2549 DMI_MATCH(DMI_PRODUCT_NAME, "Summit2"), 2550 }, 2551 }, 2552 {} 2553 }; 2554 2555 static void dmi_check_multi(void) 2556 { 2557 if (multi_checked) 2558 return; 2559 2560 dmi_check_system(multi_dmi_table); 2561 multi_checked = 1; 2562 } 2563 2564 /* 2565 * apic_is_clustered_box() -- Check if we can expect good TSC 2566 * 2567 * Thus far, the major user of this is IBM's Summit2 series: 2568 * Clustered boxes may have unsynced TSC problems if they are 2569 * multi-chassis. 2570 * Use DMI to check them 2571 */ 2572 int apic_is_clustered_box(void) 2573 { 2574 dmi_check_multi(); 2575 return multi; 2576 } 2577 #endif 2578 2579 /* 2580 * APIC command line parameters 2581 */ 2582 static int __init setup_nolapic(char *arg) 2583 { 2584 apic_is_disabled = true; 2585 setup_clear_cpu_cap(X86_FEATURE_APIC); 2586 return 0; 2587 } 2588 early_param("nolapic", setup_nolapic); 2589 2590 static int __init parse_lapic_timer_c2_ok(char *arg) 2591 { 2592 local_apic_timer_c2_ok = 1; 2593 return 0; 2594 } 2595 early_param("lapic_timer_c2_ok", parse_lapic_timer_c2_ok); 2596 2597 static int __init parse_disable_apic_timer(char *arg) 2598 { 2599 disable_apic_timer = 1; 2600 return 0; 2601 } 2602 early_param("noapictimer", parse_disable_apic_timer); 2603 2604 static int __init parse_nolapic_timer(char *arg) 2605 { 2606 disable_apic_timer = 1; 2607 return 0; 2608 } 2609 early_param("nolapic_timer", parse_nolapic_timer); 2610 2611 static int __init apic_set_verbosity(char *arg) 2612 { 2613 if (!arg) { 2614 if (IS_ENABLED(CONFIG_X86_32)) 2615 return -EINVAL; 2616 2617 ioapic_is_disabled = false; 2618 return 0; 2619 } 2620 2621 if (strcmp("debug", arg) == 0) 2622 apic_verbosity = APIC_DEBUG; 2623 else if (strcmp("verbose", arg) == 0) 2624 apic_verbosity = APIC_VERBOSE; 2625 #ifdef CONFIG_X86_64 2626 else { 2627 pr_warn("APIC Verbosity level %s not recognised" 2628 " use apic=verbose or apic=debug\n", arg); 2629 return -EINVAL; 2630 } 2631 #endif 2632 2633 return 0; 2634 } 2635 early_param("apic", apic_set_verbosity); 2636 2637 static int __init lapic_insert_resource(void) 2638 { 2639 if (!apic_mmio_base) 2640 return -1; 2641 2642 /* Put local APIC into the resource map. */ 2643 lapic_resource.start = apic_mmio_base; 2644 lapic_resource.end = lapic_resource.start + PAGE_SIZE - 1; 2645 insert_resource(&iomem_resource, &lapic_resource); 2646 2647 return 0; 2648 } 2649 2650 /* 2651 * need call insert after e820__reserve_resources() 2652 * that is using request_resource 2653 */ 2654 late_initcall(lapic_insert_resource); 2655 2656 static int __init apic_set_extnmi(char *arg) 2657 { 2658 if (!arg) 2659 return -EINVAL; 2660 2661 if (!strncmp("all", arg, 3)) 2662 apic_extnmi = APIC_EXTNMI_ALL; 2663 else if (!strncmp("none", arg, 4)) 2664 apic_extnmi = APIC_EXTNMI_NONE; 2665 else if (!strncmp("bsp", arg, 3)) 2666 apic_extnmi = APIC_EXTNMI_BSP; 2667 else { 2668 pr_warn("Unknown external NMI delivery mode `%s' ignored\n", arg); 2669 return -EINVAL; 2670 } 2671 2672 return 0; 2673 } 2674 early_param("apic_extnmi", apic_set_extnmi); 2675