/* * Local APIC handling, local APIC timers * * (c) 1999, 2000 Ingo Molnar * * Fixes * Maciej W. Rozycki : Bits for genuine 82489DX APICs; * thanks to Eric Gilmore * and Rolf G. Tews * for testing these extensively. * Maciej W. Rozycki : Various updates and fixes. * Mikael Pettersson : Power Management for UP-APIC. * Pavel Machek and * Mikael Pettersson : PM converted to driver model. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include int apic_mapped; int apic_verbosity; int apic_runs_main_timer; int apic_calibrate_pmtmr __initdata; int disable_apic_timer __initdata; /* * cpu_mask that denotes the CPUs that needs timer interrupt coming in as * IPIs in place of local APIC timers */ static cpumask_t timer_interrupt_broadcast_ipi_mask; /* Using APIC to generate smp_local_timer_interrupt? */ int using_apic_timer __read_mostly = 0; static void apic_pm_activate(void); void enable_NMI_through_LVT0 (void * dummy) { unsigned int v; v = APIC_DM_NMI; /* unmask and set to NMI */ apic_write(APIC_LVT0, v); } int get_maxlvt(void) { unsigned int v, maxlvt; v = apic_read(APIC_LVR); maxlvt = GET_APIC_MAXLVT(v); return maxlvt; } /* * 'what should we do if we get a hw irq event on an illegal vector'. * each architecture has to answer this themselves. */ void ack_bad_irq(unsigned int irq) { printk("unexpected IRQ trap at vector %02x\n", irq); /* * Currently unexpected vectors happen only on SMP and APIC. * We _must_ ack these because every local APIC has only N * irq slots per priority level, and a 'hanging, unacked' IRQ * holds up an irq slot - in excessive cases (when multiple * unexpected vectors occur) that might lock up the APIC * completely. * But don't ack when the APIC is disabled. -AK */ if (!disable_apic) ack_APIC_irq(); } void clear_local_APIC(void) { int maxlvt; unsigned int v; maxlvt = get_maxlvt(); /* * Masking an LVT entry can trigger a local APIC error * if the vector is zero. Mask LVTERR first to prevent this. */ if (maxlvt >= 3) { v = ERROR_APIC_VECTOR; /* any non-zero vector will do */ apic_write(APIC_LVTERR, v | APIC_LVT_MASKED); } /* * Careful: we have to set masks only first to deassert * any level-triggered sources. */ v = apic_read(APIC_LVTT); apic_write(APIC_LVTT, v | APIC_LVT_MASKED); v = apic_read(APIC_LVT0); apic_write(APIC_LVT0, v | APIC_LVT_MASKED); v = apic_read(APIC_LVT1); apic_write(APIC_LVT1, v | APIC_LVT_MASKED); if (maxlvt >= 4) { v = apic_read(APIC_LVTPC); apic_write(APIC_LVTPC, v | APIC_LVT_MASKED); } /* * Clean APIC state for other OSs: */ apic_write(APIC_LVTT, APIC_LVT_MASKED); apic_write(APIC_LVT0, APIC_LVT_MASKED); apic_write(APIC_LVT1, APIC_LVT_MASKED); if (maxlvt >= 3) apic_write(APIC_LVTERR, APIC_LVT_MASKED); if (maxlvt >= 4) apic_write(APIC_LVTPC, APIC_LVT_MASKED); v = GET_APIC_VERSION(apic_read(APIC_LVR)); apic_write(APIC_ESR, 0); apic_read(APIC_ESR); } void disconnect_bsp_APIC(int virt_wire_setup) { /* Go back to Virtual Wire compatibility mode */ unsigned long value; /* For the spurious interrupt use vector F, and enable it */ value = apic_read(APIC_SPIV); value &= ~APIC_VECTOR_MASK; value |= APIC_SPIV_APIC_ENABLED; value |= 0xf; apic_write(APIC_SPIV, value); if (!virt_wire_setup) { /* For LVT0 make it edge triggered, active high, external and enabled */ value = apic_read(APIC_LVT0); value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING | APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR | APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED ); value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING; value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT); apic_write(APIC_LVT0, value); } else { /* Disable LVT0 */ apic_write(APIC_LVT0, APIC_LVT_MASKED); } /* For LVT1 make it edge triggered, active high, nmi and enabled */ value = apic_read(APIC_LVT1); value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING | APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR | APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED); value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING; value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI); apic_write(APIC_LVT1, value); } void disable_local_APIC(void) { unsigned int value; clear_local_APIC(); /* * Disable APIC (implies clearing of registers * for 82489DX!). */ value = apic_read(APIC_SPIV); value &= ~APIC_SPIV_APIC_ENABLED; apic_write(APIC_SPIV, value); } /* * This is to verify that we're looking at a real local APIC. * Check these against your board if the CPUs aren't getting * started for no apparent reason. */ int __init verify_local_APIC(void) { unsigned int reg0, reg1; /* * The version register is read-only in a real APIC. */ reg0 = apic_read(APIC_LVR); apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg0); apic_write(APIC_LVR, reg0 ^ APIC_LVR_MASK); reg1 = apic_read(APIC_LVR); apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg1); /* * The two version reads above should print the same * numbers. If the second one is different, then we * poke at a non-APIC. */ if (reg1 != reg0) return 0; /* * Check if the version looks reasonably. */ reg1 = GET_APIC_VERSION(reg0); if (reg1 == 0x00 || reg1 == 0xff) return 0; reg1 = get_maxlvt(); if (reg1 < 0x02 || reg1 == 0xff) return 0; /* * The ID register is read/write in a real APIC. */ reg0 = apic_read(APIC_ID); apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg0); apic_write(APIC_ID, reg0 ^ APIC_ID_MASK); reg1 = apic_read(APIC_ID); apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg1); apic_write(APIC_ID, reg0); if (reg1 != (reg0 ^ APIC_ID_MASK)) return 0; /* * The next two are just to see if we have sane values. * They're only really relevant if we're in Virtual Wire * compatibility mode, but most boxes are anymore. */ reg0 = apic_read(APIC_LVT0); apic_printk(APIC_DEBUG,"Getting LVT0: %x\n", reg0); reg1 = apic_read(APIC_LVT1); apic_printk(APIC_DEBUG, "Getting LVT1: %x\n", reg1); return 1; } void __init sync_Arb_IDs(void) { /* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 */ unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR)); if (ver >= 0x14) /* P4 or higher */ return; /* * Wait for idle. */ apic_wait_icr_idle(); apic_printk(APIC_DEBUG, "Synchronizing Arb IDs.\n"); apic_write(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG | APIC_DM_INIT); } /* * An initial setup of the virtual wire mode. */ void __init init_bsp_APIC(void) { unsigned int value; /* * Don't do the setup now if we have a SMP BIOS as the * through-I/O-APIC virtual wire mode might be active. */ if (smp_found_config || !cpu_has_apic) return; value = apic_read(APIC_LVR); /* * Do not trust the local APIC being empty at bootup. */ clear_local_APIC(); /* * Enable APIC. */ value = apic_read(APIC_SPIV); value &= ~APIC_VECTOR_MASK; value |= APIC_SPIV_APIC_ENABLED; value |= APIC_SPIV_FOCUS_DISABLED; value |= SPURIOUS_APIC_VECTOR; apic_write(APIC_SPIV, value); /* * Set up the virtual wire mode. */ apic_write(APIC_LVT0, APIC_DM_EXTINT); value = APIC_DM_NMI; apic_write(APIC_LVT1, value); } void __cpuinit setup_local_APIC (void) { unsigned int value, maxlvt; int i, j; value = apic_read(APIC_LVR); BUILD_BUG_ON((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f); /* * Double-check whether this APIC is really registered. * This is meaningless in clustered apic mode, so we skip it. */ if (!apic_id_registered()) BUG(); /* * Intel recommends to set DFR, LDR and TPR before enabling * an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel * document number 292116). So here it goes... */ init_apic_ldr(); /* * Set Task Priority to 'accept all'. We never change this * later on. */ value = apic_read(APIC_TASKPRI); value &= ~APIC_TPRI_MASK; apic_write(APIC_TASKPRI, value); /* * After a crash, we no longer service the interrupts and a pending * interrupt from previous kernel might still have ISR bit set. * * Most probably by now CPU has serviced that pending interrupt and * it might not have done the ack_APIC_irq() because it thought, * interrupt came from i8259 as ExtInt. LAPIC did not get EOI so it * does not clear the ISR bit and cpu thinks it has already serivced * the interrupt. Hence a vector might get locked. It was noticed * for timer irq (vector 0x31). Issue an extra EOI to clear ISR. */ for (i = APIC_ISR_NR - 1; i >= 0; i--) { value = apic_read(APIC_ISR + i*0x10); for (j = 31; j >= 0; j--) { if (value & (1< 3) apic_write(APIC_ESR, 0); value = apic_read(APIC_ESR); if (value != oldvalue) apic_printk(APIC_VERBOSE, "ESR value after enabling vector: %08x, after %08x\n", oldvalue, value); } nmi_watchdog_default(); setup_apic_nmi_watchdog(NULL); apic_pm_activate(); } #ifdef CONFIG_PM static struct { /* 'active' is true if the local APIC was enabled by us and not the BIOS; this signifies that we are also responsible for disabling it before entering apm/acpi suspend */ int active; /* r/w apic fields */ unsigned int apic_id; unsigned int apic_taskpri; unsigned int apic_ldr; unsigned int apic_dfr; unsigned int apic_spiv; unsigned int apic_lvtt; unsigned int apic_lvtpc; unsigned int apic_lvt0; unsigned int apic_lvt1; unsigned int apic_lvterr; unsigned int apic_tmict; unsigned int apic_tdcr; unsigned int apic_thmr; } apic_pm_state; static int lapic_suspend(struct sys_device *dev, pm_message_t state) { unsigned long flags; if (!apic_pm_state.active) return 0; apic_pm_state.apic_id = apic_read(APIC_ID); apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI); apic_pm_state.apic_ldr = apic_read(APIC_LDR); apic_pm_state.apic_dfr = apic_read(APIC_DFR); apic_pm_state.apic_spiv = apic_read(APIC_SPIV); apic_pm_state.apic_lvtt = apic_read(APIC_LVTT); apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC); apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0); apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1); apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR); apic_pm_state.apic_tmict = apic_read(APIC_TMICT); apic_pm_state.apic_tdcr = apic_read(APIC_TDCR); apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR); local_irq_save(flags); disable_local_APIC(); local_irq_restore(flags); return 0; } static int lapic_resume(struct sys_device *dev) { unsigned int l, h; unsigned long flags; if (!apic_pm_state.active) return 0; local_irq_save(flags); rdmsr(MSR_IA32_APICBASE, l, h); l &= ~MSR_IA32_APICBASE_BASE; l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr; wrmsr(MSR_IA32_APICBASE, l, h); apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED); apic_write(APIC_ID, apic_pm_state.apic_id); apic_write(APIC_DFR, apic_pm_state.apic_dfr); apic_write(APIC_LDR, apic_pm_state.apic_ldr); apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri); apic_write(APIC_SPIV, apic_pm_state.apic_spiv); apic_write(APIC_LVT0, apic_pm_state.apic_lvt0); apic_write(APIC_LVT1, apic_pm_state.apic_lvt1); apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr); apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc); apic_write(APIC_LVTT, apic_pm_state.apic_lvtt); apic_write(APIC_TDCR, apic_pm_state.apic_tdcr); apic_write(APIC_TMICT, apic_pm_state.apic_tmict); apic_write(APIC_ESR, 0); apic_read(APIC_ESR); apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr); apic_write(APIC_ESR, 0); apic_read(APIC_ESR); local_irq_restore(flags); return 0; } static struct sysdev_class lapic_sysclass = { set_kset_name("lapic"), .resume = lapic_resume, .suspend = lapic_suspend, }; static struct sys_device device_lapic = { .id = 0, .cls = &lapic_sysclass, }; static void __cpuinit apic_pm_activate(void) { apic_pm_state.active = 1; } static int __init init_lapic_sysfs(void) { int error; if (!cpu_has_apic) return 0; /* XXX: remove suspend/resume procs if !apic_pm_state.active? */ error = sysdev_class_register(&lapic_sysclass); if (!error) error = sysdev_register(&device_lapic); return error; } device_initcall(init_lapic_sysfs); #else /* CONFIG_PM */ static void apic_pm_activate(void) { } #endif /* CONFIG_PM */ static int __init apic_set_verbosity(char *str) { if (str == NULL) { skip_ioapic_setup = 0; ioapic_force = 1; return 0; } if (strcmp("debug", str) == 0) apic_verbosity = APIC_DEBUG; else if (strcmp("verbose", str) == 0) apic_verbosity = APIC_VERBOSE; else { printk(KERN_WARNING "APIC Verbosity level %s not recognised" " use apic=verbose or apic=debug\n", str); return -EINVAL; } return 0; } early_param("apic", apic_set_verbosity); /* * Detect and enable local APICs on non-SMP boards. * Original code written by Keir Fraser. * On AMD64 we trust the BIOS - if it says no APIC it is likely * not correctly set up (usually the APIC timer won't work etc.) */ static int __init detect_init_APIC (void) { if (!cpu_has_apic) { printk(KERN_INFO "No local APIC present\n"); return -1; } mp_lapic_addr = APIC_DEFAULT_PHYS_BASE; boot_cpu_id = 0; return 0; } void __init init_apic_mappings(void) { unsigned long apic_phys; /* * If no local APIC can be found then set up a fake all * zeroes page to simulate the local APIC and another * one for the IO-APIC. */ if (!smp_found_config && detect_init_APIC()) { apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE); apic_phys = __pa(apic_phys); } else apic_phys = mp_lapic_addr; set_fixmap_nocache(FIX_APIC_BASE, apic_phys); apic_mapped = 1; apic_printk(APIC_VERBOSE,"mapped APIC to %16lx (%16lx)\n", APIC_BASE, apic_phys); /* * Fetch the APIC ID of the BSP in case we have a * default configuration (or the MP table is broken). */ boot_cpu_id = GET_APIC_ID(apic_read(APIC_ID)); { unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0; int i; for (i = 0; i < nr_ioapics; i++) { if (smp_found_config) { ioapic_phys = mp_ioapics[i].mpc_apicaddr; } else { ioapic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE); ioapic_phys = __pa(ioapic_phys); } set_fixmap_nocache(idx, ioapic_phys); apic_printk(APIC_VERBOSE,"mapped IOAPIC to %016lx (%016lx)\n", __fix_to_virt(idx), ioapic_phys); idx++; } } } /* * This function sets up the local APIC timer, with a timeout of * 'clocks' APIC bus clock. During calibration we actually call * this function twice on the boot CPU, once with a bogus timeout * value, second time for real. The other (noncalibrating) CPUs * call this function only once, with the real, calibrated value. * * We do reads before writes even if unnecessary, to get around the * P5 APIC double write bug. */ #define APIC_DIVISOR 16 static void __setup_APIC_LVTT(unsigned int clocks) { unsigned int lvtt_value, tmp_value, ver; int cpu = smp_processor_id(); ver = GET_APIC_VERSION(apic_read(APIC_LVR)); lvtt_value = APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR; if (cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) lvtt_value |= APIC_LVT_MASKED; apic_write(APIC_LVTT, lvtt_value); /* * Divide PICLK by 16 */ tmp_value = apic_read(APIC_TDCR); apic_write(APIC_TDCR, (tmp_value & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE)) | APIC_TDR_DIV_16); apic_write(APIC_TMICT, clocks/APIC_DIVISOR); } static void setup_APIC_timer(unsigned int clocks) { unsigned long flags; local_irq_save(flags); /* wait for irq slice */ if (vxtime.hpet_address && hpet_use_timer) { int trigger = hpet_readl(HPET_T0_CMP); while (hpet_readl(HPET_COUNTER) >= trigger) /* do nothing */ ; while (hpet_readl(HPET_COUNTER) < trigger) /* do nothing */ ; } else { int c1, c2; outb_p(0x00, 0x43); c2 = inb_p(0x40); c2 |= inb_p(0x40) << 8; do { c1 = c2; outb_p(0x00, 0x43); c2 = inb_p(0x40); c2 |= inb_p(0x40) << 8; } while (c2 - c1 < 300); } __setup_APIC_LVTT(clocks); /* Turn off PIT interrupt if we use APIC timer as main timer. Only works with the PM timer right now TBD fix it for HPET too. */ if (vxtime.mode == VXTIME_PMTMR && smp_processor_id() == boot_cpu_id && apic_runs_main_timer == 1 && !cpu_isset(boot_cpu_id, timer_interrupt_broadcast_ipi_mask)) { stop_timer_interrupt(); apic_runs_main_timer++; } local_irq_restore(flags); } /* * In this function we calibrate APIC bus clocks to the external * timer. Unfortunately we cannot use jiffies and the timer irq * to calibrate, since some later bootup code depends on getting * the first irq? Ugh. * * We want to do the calibration only once since we * want to have local timer irqs syncron. CPUs connected * by the same APIC bus have the very same bus frequency. * And we want to have irqs off anyways, no accidental * APIC irq that way. */ #define TICK_COUNT 100000000 static int __init calibrate_APIC_clock(void) { int apic, apic_start, tsc, tsc_start; int result; /* * Put whatever arbitrary (but long enough) timeout * value into the APIC clock, we just want to get the * counter running for calibration. */ __setup_APIC_LVTT(1000000000); apic_start = apic_read(APIC_TMCCT); #ifdef CONFIG_X86_PM_TIMER if (apic_calibrate_pmtmr && pmtmr_ioport) { pmtimer_wait(5000); /* 5ms wait */ apic = apic_read(APIC_TMCCT); result = (apic_start - apic) * 1000L / 5; } else #endif { rdtscl(tsc_start); do { apic = apic_read(APIC_TMCCT); rdtscl(tsc); } while ((tsc - tsc_start) < TICK_COUNT && (apic - apic_start) < TICK_COUNT); result = (apic_start - apic) * 1000L * cpu_khz / (tsc - tsc_start); } printk("result %d\n", result); printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n", result / 1000 / 1000, result / 1000 % 1000); return result * APIC_DIVISOR / HZ; } static unsigned int calibration_result; void __init setup_boot_APIC_clock (void) { if (disable_apic_timer) { printk(KERN_INFO "Disabling APIC timer\n"); return; } printk(KERN_INFO "Using local APIC timer interrupts.\n"); using_apic_timer = 1; local_irq_disable(); calibration_result = calibrate_APIC_clock(); /* * Now set up the timer for real. */ setup_APIC_timer(calibration_result); local_irq_enable(); } void __cpuinit setup_secondary_APIC_clock(void) { local_irq_disable(); /* FIXME: Do we need this? --RR */ setup_APIC_timer(calibration_result); local_irq_enable(); } void disable_APIC_timer(void) { if (using_apic_timer) { unsigned long v; v = apic_read(APIC_LVTT); /* * When an illegal vector value (0-15) is written to an LVT * entry and delivery mode is Fixed, the APIC may signal an * illegal vector error, with out regard to whether the mask * bit is set or whether an interrupt is actually seen on input. * * Boot sequence might call this function when the LVTT has * '0' vector value. So make sure vector field is set to * valid value. */ v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR); apic_write(APIC_LVTT, v); } } void enable_APIC_timer(void) { int cpu = smp_processor_id(); if (using_apic_timer && !cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) { unsigned long v; v = apic_read(APIC_LVTT); apic_write(APIC_LVTT, v & ~APIC_LVT_MASKED); } } void switch_APIC_timer_to_ipi(void *cpumask) { cpumask_t mask = *(cpumask_t *)cpumask; int cpu = smp_processor_id(); if (cpu_isset(cpu, mask) && !cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) { disable_APIC_timer(); cpu_set(cpu, timer_interrupt_broadcast_ipi_mask); } } EXPORT_SYMBOL(switch_APIC_timer_to_ipi); void smp_send_timer_broadcast_ipi(void) { cpumask_t mask; cpus_and(mask, cpu_online_map, timer_interrupt_broadcast_ipi_mask); if (!cpus_empty(mask)) { send_IPI_mask(mask, LOCAL_TIMER_VECTOR); } } void switch_ipi_to_APIC_timer(void *cpumask) { cpumask_t mask = *(cpumask_t *)cpumask; int cpu = smp_processor_id(); if (cpu_isset(cpu, mask) && cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) { cpu_clear(cpu, timer_interrupt_broadcast_ipi_mask); enable_APIC_timer(); } } EXPORT_SYMBOL(switch_ipi_to_APIC_timer); int setup_profiling_timer(unsigned int multiplier) { return -EINVAL; } void setup_APIC_extened_lvt(unsigned char lvt_off, unsigned char vector, unsigned char msg_type, unsigned char mask) { unsigned long reg = (lvt_off << 4) + K8_APIC_EXT_LVT_BASE; unsigned int v = (mask << 16) | (msg_type << 8) | vector; apic_write(reg, v); } #undef APIC_DIVISOR /* * Local timer interrupt handler. It does both profiling and * process statistics/rescheduling. * * We do profiling in every local tick, statistics/rescheduling * happen only every 'profiling multiplier' ticks. The default * multiplier is 1 and it can be changed by writing the new multiplier * value into /proc/profile. */ void smp_local_timer_interrupt(void) { profile_tick(CPU_PROFILING); #ifdef CONFIG_SMP update_process_times(user_mode(get_irq_regs())); #endif if (apic_runs_main_timer > 1 && smp_processor_id() == boot_cpu_id) main_timer_handler(); /* * We take the 'long' return path, and there every subsystem * grabs the appropriate locks (kernel lock/ irq lock). * * We might want to decouple profiling from the 'long path', * and do the profiling totally in assembly. * * Currently this isn't too much of an issue (performance wise), * we can take more than 100K local irqs per second on a 100 MHz P5. */ } /* * Local APIC timer interrupt. This is the most natural way for doing * local interrupts, but local timer interrupts can be emulated by * broadcast interrupts too. [in case the hw doesn't support APIC timers] * * [ if a single-CPU system runs an SMP kernel then we call the local * interrupt as well. Thus we cannot inline the local irq ... ] */ void smp_apic_timer_interrupt(void) { /* * the NMI deadlock-detector uses this. */ add_pda(apic_timer_irqs, 1); /* * NOTE! We'd better ACK the irq immediately, * because timer handling can be slow. */ ack_APIC_irq(); /* * update_process_times() expects us to have done irq_enter(). * Besides, if we don't timer interrupts ignore the global * interrupt lock, which is the WrongThing (tm) to do. */ exit_idle(); irq_enter(); smp_local_timer_interrupt(); irq_exit(); } /* * apic_is_clustered_box() -- Check if we can expect good TSC * * Thus far, the major user of this is IBM's Summit2 series: * * Clustered boxes may have unsynced TSC problems if they are * multi-chassis. Use available data to take a good guess. * If in doubt, go HPET. */ __cpuinit int apic_is_clustered_box(void) { int i, clusters, zeros; unsigned id; DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS); bitmap_zero(clustermap, NUM_APIC_CLUSTERS); for (i = 0; i < NR_CPUS; i++) { id = bios_cpu_apicid[i]; if (id != BAD_APICID) __set_bit(APIC_CLUSTERID(id), clustermap); } /* Problem: Partially populated chassis may not have CPUs in some of * the APIC clusters they have been allocated. Only present CPUs have * bios_cpu_apicid entries, thus causing zeroes in the bitmap. Since * clusters are allocated sequentially, count zeros only if they are * bounded by ones. */ clusters = 0; zeros = 0; for (i = 0; i < NUM_APIC_CLUSTERS; i++) { if (test_bit(i, clustermap)) { clusters += 1 + zeros; zeros = 0; } else ++zeros; } /* * If clusters > 2, then should be multi-chassis. * May have to revisit this when multi-core + hyperthreaded CPUs come * out, but AFAIK this will work even for them. */ return (clusters > 2); } /* * This interrupt should _never_ happen with our APIC/SMP architecture */ asmlinkage void smp_spurious_interrupt(void) { unsigned int v; exit_idle(); irq_enter(); /* * Check if this really is a spurious interrupt and ACK it * if it is a vectored one. Just in case... * Spurious interrupts should not be ACKed. */ v = apic_read(APIC_ISR + ((SPURIOUS_APIC_VECTOR & ~0x1f) >> 1)); if (v & (1 << (SPURIOUS_APIC_VECTOR & 0x1f))) ack_APIC_irq(); #if 0 static unsigned long last_warning; static unsigned long skipped; /* see sw-dev-man vol 3, chapter 7.4.13.5 */ if (time_before(last_warning+30*HZ,jiffies)) { printk(KERN_INFO "spurious APIC interrupt on CPU#%d, %ld skipped.\n", smp_processor_id(), skipped); last_warning = jiffies; skipped = 0; } else { skipped++; } #endif irq_exit(); } /* * This interrupt should never happen with our APIC/SMP architecture */ asmlinkage void smp_error_interrupt(void) { unsigned int v, v1; exit_idle(); irq_enter(); /* First tickle the hardware, only then report what went on. -- REW */ v = apic_read(APIC_ESR); apic_write(APIC_ESR, 0); v1 = apic_read(APIC_ESR); ack_APIC_irq(); atomic_inc(&irq_err_count); /* Here is what the APIC error bits mean: 0: Send CS error 1: Receive CS error 2: Send accept error 3: Receive accept error 4: Reserved 5: Send illegal vector 6: Received illegal vector 7: Illegal register address */ printk (KERN_DEBUG "APIC error on CPU%d: %02x(%02x)\n", smp_processor_id(), v , v1); irq_exit(); } int disable_apic; /* * This initializes the IO-APIC and APIC hardware if this is * a UP kernel. */ int __init APIC_init_uniprocessor (void) { if (disable_apic) { printk(KERN_INFO "Apic disabled\n"); return -1; } if (!cpu_has_apic) { disable_apic = 1; printk(KERN_INFO "Apic disabled by BIOS\n"); return -1; } verify_local_APIC(); phys_cpu_present_map = physid_mask_of_physid(boot_cpu_id); apic_write(APIC_ID, SET_APIC_ID(boot_cpu_id)); setup_local_APIC(); if (smp_found_config && !skip_ioapic_setup && nr_ioapics) setup_IO_APIC(); else nr_ioapics = 0; setup_boot_APIC_clock(); check_nmi_watchdog(); return 0; } static __init int setup_disableapic(char *str) { disable_apic = 1; clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability); return 0; } early_param("disableapic", setup_disableapic); /* same as disableapic, for compatibility */ static __init int setup_nolapic(char *str) { return setup_disableapic(str); } early_param("nolapic", setup_nolapic); static __init int setup_noapictimer(char *str) { if (str[0] != ' ' && str[0] != 0) return 0; disable_apic_timer = 1; return 1; } static __init int setup_apicmaintimer(char *str) { apic_runs_main_timer = 1; nohpet = 1; return 1; } __setup("apicmaintimer", setup_apicmaintimer); static __init int setup_noapicmaintimer(char *str) { apic_runs_main_timer = -1; return 1; } __setup("noapicmaintimer", setup_noapicmaintimer); static __init int setup_apicpmtimer(char *s) { apic_calibrate_pmtmr = 1; notsc_setup(NULL); return setup_apicmaintimer(NULL); } __setup("apicpmtimer", setup_apicpmtimer); __setup("noapictimer", setup_noapictimer);