/* * 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 "io_ports.h" /* * Debug level */ int apic_verbosity; static void apic_pm_activate(void); /* * '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. */ ack_APIC_irq(); } void __init apic_intr_init(void) { #ifdef CONFIG_SMP smp_intr_init(); #endif /* self generated IPI for local APIC timer */ set_intr_gate(LOCAL_TIMER_VECTOR, apic_timer_interrupt); /* IPI vectors for APIC spurious and error interrupts */ set_intr_gate(SPURIOUS_APIC_VECTOR, spurious_interrupt); set_intr_gate(ERROR_APIC_VECTOR, error_interrupt); /* thermal monitor LVT interrupt */ #ifdef CONFIG_X86_MCE_P4THERMAL set_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt); #endif } /* Using APIC to generate smp_local_timer_interrupt? */ int using_apic_timer = 0; static DEFINE_PER_CPU(int, prof_multiplier) = 1; static DEFINE_PER_CPU(int, prof_old_multiplier) = 1; static DEFINE_PER_CPU(int, prof_counter) = 1; static int enabled_via_apicbase; void enable_NMI_through_LVT0 (void * dummy) { unsigned int v, ver; ver = apic_read(APIC_LVR); ver = GET_APIC_VERSION(ver); v = APIC_DM_NMI; /* unmask and set to NMI */ if (!APIC_INTEGRATED(ver)) /* 82489DX */ v |= APIC_LVT_LEVEL_TRIGGER; apic_write_around(APIC_LVT0, v); } int get_physical_broadcast(void) { unsigned int lvr, version; lvr = apic_read(APIC_LVR); version = GET_APIC_VERSION(lvr); if (!APIC_INTEGRATED(version) || version >= 0x14) return 0xff; else return 0xf; } int get_maxlvt(void) { unsigned int v, ver, maxlvt; v = apic_read(APIC_LVR); ver = GET_APIC_VERSION(v); /* 82489DXs do not report # of LVT entries. */ maxlvt = APIC_INTEGRATED(ver) ? GET_APIC_MAXLVT(v) : 2; return maxlvt; } void clear_local_APIC(void) { int maxlvt; unsigned long v; maxlvt = get_maxlvt(); /* * Masking an LVT entry on a P6 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_around(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_around(APIC_LVTT, v | APIC_LVT_MASKED); v = apic_read(APIC_LVT0); apic_write_around(APIC_LVT0, v | APIC_LVT_MASKED); v = apic_read(APIC_LVT1); apic_write_around(APIC_LVT1, v | APIC_LVT_MASKED); if (maxlvt >= 4) { v = apic_read(APIC_LVTPC); apic_write_around(APIC_LVTPC, v | APIC_LVT_MASKED); } /* lets not touch this if we didn't frob it */ #ifdef CONFIG_X86_MCE_P4THERMAL if (maxlvt >= 5) { v = apic_read(APIC_LVTTHMR); apic_write_around(APIC_LVTTHMR, v | APIC_LVT_MASKED); } #endif /* * Clean APIC state for other OSs: */ apic_write_around(APIC_LVTT, APIC_LVT_MASKED); apic_write_around(APIC_LVT0, APIC_LVT_MASKED); apic_write_around(APIC_LVT1, APIC_LVT_MASKED); if (maxlvt >= 3) apic_write_around(APIC_LVTERR, APIC_LVT_MASKED); if (maxlvt >= 4) apic_write_around(APIC_LVTPC, APIC_LVT_MASKED); #ifdef CONFIG_X86_MCE_P4THERMAL if (maxlvt >= 5) apic_write_around(APIC_LVTTHMR, APIC_LVT_MASKED); #endif v = GET_APIC_VERSION(apic_read(APIC_LVR)); if (APIC_INTEGRATED(v)) { /* !82489DX */ if (maxlvt > 3) /* Due to Pentium errata 3AP and 11AP. */ apic_write(APIC_ESR, 0); apic_read(APIC_ESR); } } void __init connect_bsp_APIC(void) { if (pic_mode) { /* * Do not trust the local APIC being empty at bootup. */ clear_local_APIC(); /* * PIC mode, enable APIC mode in the IMCR, i.e. * connect BSP's local APIC to INT and NMI lines. */ apic_printk(APIC_VERBOSE, "leaving PIC mode, " "enabling APIC mode.\n"); outb(0x70, 0x22); outb(0x01, 0x23); } enable_apic_mode(); } void disconnect_bsp_APIC(void) { if (pic_mode) { /* * Put the board back into PIC mode (has an effect * only on certain older boards). Note that APIC * interrupts, including IPIs, won't work beyond * this point! The only exception are INIT IPIs. */ apic_printk(APIC_VERBOSE, "disabling APIC mode, " "entering PIC mode.\n"); outb(0x70, 0x22); outb(0x00, 0x23); } } void disable_local_APIC(void) { unsigned long value; clear_local_APIC(); /* * Disable APIC (implies clearing of registers * for 82489DX!). */ value = apic_read(APIC_SPIV); value &= ~APIC_SPIV_APIC_ENABLED; apic_write_around(APIC_SPIV, value); if (enabled_via_apicbase) { unsigned int l, h; rdmsr(MSR_IA32_APICBASE, l, h); l &= ~MSR_IA32_APICBASE_ENABLE; wrmsr(MSR_IA32_APICBASE, l, h); } } /* * 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); /* * 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_around(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG | APIC_DM_INIT); } extern void __error_in_apic_c (void); /* * An initial setup of the virtual wire mode. */ void __init init_bsp_APIC(void) { unsigned long value, ver; /* * 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); ver = GET_APIC_VERSION(value); /* * 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; /* This bit is reserved on P4/Xeon and should be cleared */ if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 15)) value &= ~APIC_SPIV_FOCUS_DISABLED; else value |= APIC_SPIV_FOCUS_DISABLED; value |= SPURIOUS_APIC_VECTOR; apic_write_around(APIC_SPIV, value); /* * Set up the virtual wire mode. */ apic_write_around(APIC_LVT0, APIC_DM_EXTINT); value = APIC_DM_NMI; if (!APIC_INTEGRATED(ver)) /* 82489DX */ value |= APIC_LVT_LEVEL_TRIGGER; apic_write_around(APIC_LVT1, value); } void __init setup_local_APIC (void) { unsigned long oldvalue, value, ver, maxlvt; /* Pound the ESR really hard over the head with a big hammer - mbligh */ if (esr_disable) { apic_write(APIC_ESR, 0); apic_write(APIC_ESR, 0); apic_write(APIC_ESR, 0); apic_write(APIC_ESR, 0); } value = apic_read(APIC_LVR); ver = GET_APIC_VERSION(value); if ((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f) __error_in_apic_c(); /* * Double-check whether this APIC is really registered. */ 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_around(APIC_TASKPRI, value); /* * Now that we are all set up, enable the APIC */ value = apic_read(APIC_SPIV); value &= ~APIC_VECTOR_MASK; /* * Enable APIC */ value |= APIC_SPIV_APIC_ENABLED; /* * Some unknown Intel IO/APIC (or APIC) errata is biting us with * certain networking cards. If high frequency interrupts are * happening on a particular IOAPIC pin, plus the IOAPIC routing * entry is masked/unmasked at a high rate as well then sooner or * later IOAPIC line gets 'stuck', no more interrupts are received * from the device. If focus CPU is disabled then the hang goes * away, oh well :-( * * [ This bug can be reproduced easily with a level-triggered * PCI Ne2000 networking cards and PII/PIII processors, dual * BX chipset. ] */ /* * Actually disabling the focus CPU check just makes the hang less * frequent as it makes the interrupt distributon model be more * like LRU than MRU (the short-term load is more even across CPUs). * See also the comment in end_level_ioapic_irq(). --macro */ #if 1 /* Enable focus processor (bit==0) */ value &= ~APIC_SPIV_FOCUS_DISABLED; #else /* Disable focus processor (bit==1) */ value |= APIC_SPIV_FOCUS_DISABLED; #endif /* * Set spurious IRQ vector */ value |= SPURIOUS_APIC_VECTOR; apic_write_around(APIC_SPIV, value); /* * Set up LVT0, LVT1: * * set up through-local-APIC on the BP's LINT0. This is not * strictly necessery in pure symmetric-IO mode, but sometimes * we delegate interrupts to the 8259A. */ /* * TODO: set up through-local-APIC from through-I/O-APIC? --macro */ value = apic_read(APIC_LVT0) & APIC_LVT_MASKED; if (!smp_processor_id() && (pic_mode || !value)) { value = APIC_DM_EXTINT; apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n", smp_processor_id()); } else { value = APIC_DM_EXTINT | APIC_LVT_MASKED; apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n", smp_processor_id()); } apic_write_around(APIC_LVT0, value); /* * only the BP should see the LINT1 NMI signal, obviously. */ if (!smp_processor_id()) value = APIC_DM_NMI; else value = APIC_DM_NMI | APIC_LVT_MASKED; if (!APIC_INTEGRATED(ver)) /* 82489DX */ value |= APIC_LVT_LEVEL_TRIGGER; apic_write_around(APIC_LVT1, value); if (APIC_INTEGRATED(ver) && !esr_disable) { /* !82489DX */ maxlvt = get_maxlvt(); if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ apic_write(APIC_ESR, 0); oldvalue = apic_read(APIC_ESR); value = ERROR_APIC_VECTOR; // enables sending errors apic_write_around(APIC_LVTERR, value); /* * spec says clear errors after enabling vector. */ if (maxlvt > 3) apic_write(APIC_ESR, 0); value = apic_read(APIC_ESR); if (value != oldvalue) apic_printk(APIC_VERBOSE, "ESR value before enabling " "vector: 0x%08lx after: 0x%08lx\n", oldvalue, value); } else { if (esr_disable) /* * Something untraceble is creating bad interrupts on * secondary quads ... for the moment, just leave the * ESR disabled - we can't do anything useful with the * errors anyway - mbligh */ printk("Leaving ESR disabled.\n"); else printk("No ESR for 82489DX.\n"); } if (nmi_watchdog == NMI_LOCAL_APIC) setup_apic_nmi_watchdog(); apic_pm_activate(); } /* * If Linux enabled the LAPIC against the BIOS default * disable it down before re-entering the BIOS on shutdown. * Otherwise the BIOS may get confused and not power-off. */ void lapic_shutdown(void) { if (!cpu_has_apic || !enabled_via_apicbase) return; local_irq_disable(); disable_local_APIC(); local_irq_enable(); } #ifdef CONFIG_PM static struct { 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); /* * Make sure the APICBASE points to the right address * * FIXME! This will be wrong if we ever support suspend on * SMP! We'll need to do this as part of the CPU restore! */ 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; } /* * This device has no shutdown method - fully functioning local APICs * are needed on every CPU up until machine_halt/restart/poweroff. */ 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 __init 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 */ /* * Detect and enable local APICs on non-SMP boards. * Original code written by Keir Fraser. */ /* * Knob to control our willingness to enable the local APIC. */ int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */ static int __init lapic_disable(char *str) { enable_local_apic = -1; clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability); return 0; } __setup("nolapic", lapic_disable); static int __init lapic_enable(char *str) { enable_local_apic = 1; return 0; } __setup("lapic", lapic_enable); static int __init apic_set_verbosity(char *str) { 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", str); return 0; } __setup("apic=", apic_set_verbosity); static int __init detect_init_APIC (void) { u32 h, l, features; extern void get_cpu_vendor(struct cpuinfo_x86*); /* Disabled by kernel option? */ if (enable_local_apic < 0) return -1; /* Workaround for us being called before identify_cpu(). */ get_cpu_vendor(&boot_cpu_data); switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: if ((boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model > 1) || (boot_cpu_data.x86 == 15)) break; goto no_apic; case X86_VENDOR_INTEL: if (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15 || (boot_cpu_data.x86 == 5 && cpu_has_apic)) break; goto no_apic; default: goto no_apic; } if (!cpu_has_apic) { /* * Over-ride BIOS and try to enable the local * APIC only if "lapic" specified. */ if (enable_local_apic <= 0) { printk("Local APIC disabled by BIOS -- " "you can enable it with \"lapic\"\n"); return -1; } /* * Some BIOSes disable the local APIC in the * APIC_BASE MSR. This can only be done in * software for Intel P6 or later and AMD K7 * (Model > 1) or later. */ rdmsr(MSR_IA32_APICBASE, l, h); if (!(l & MSR_IA32_APICBASE_ENABLE)) { printk("Local APIC disabled by BIOS -- reenabling.\n"); l &= ~MSR_IA32_APICBASE_BASE; l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE; wrmsr(MSR_IA32_APICBASE, l, h); enabled_via_apicbase = 1; } } /* * The APIC feature bit should now be enabled * in `cpuid' */ features = cpuid_edx(1); if (!(features & (1 << X86_FEATURE_APIC))) { printk("Could not enable APIC!\n"); return -1; } set_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability); mp_lapic_addr = APIC_DEFAULT_PHYS_BASE; /* The BIOS may have set up the APIC at some other address */ rdmsr(MSR_IA32_APICBASE, l, h); if (l & MSR_IA32_APICBASE_ENABLE) mp_lapic_addr = l & MSR_IA32_APICBASE_BASE; if (nmi_watchdog != NMI_NONE) nmi_watchdog = NMI_LOCAL_APIC; printk("Found and enabled local APIC!\n"); apic_pm_activate(); return 0; no_apic: printk("No local APIC present or hardware disabled\n"); return -1; } 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); printk(KERN_DEBUG "mapped APIC to %08lx (%08lx)\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). */ if (boot_cpu_physical_apicid == -1U) boot_cpu_physical_apicid = GET_APIC_ID(apic_read(APIC_ID)); #ifdef CONFIG_X86_IO_APIC { 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; if (!ioapic_phys) { printk(KERN_ERR "WARNING: bogus zero IO-APIC " "address found in MPTABLE, " "disabling IO/APIC support!\n"); smp_found_config = 0; skip_ioapic_setup = 1; goto fake_ioapic_page; } } else { fake_ioapic_page: ioapic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE); ioapic_phys = __pa(ioapic_phys); } set_fixmap_nocache(idx, ioapic_phys); printk(KERN_DEBUG "mapped IOAPIC to %08lx (%08lx)\n", __fix_to_virt(idx), ioapic_phys); idx++; } } #endif } /* * This part sets up the APIC 32 bit clock in LVTT1, with HZ interrupts * per second. We assume that the caller has already set up the local * APIC. * * The APIC timer is not exactly sync with the external timer chip, it * closely follows bus clocks. */ /* * The timer chip is already set up at HZ interrupts per second here, * but we do not accept timer interrupts yet. We only allow the BP * to calibrate. */ static unsigned int __init get_8254_timer_count(void) { extern spinlock_t i8253_lock; unsigned long flags; unsigned int count; spin_lock_irqsave(&i8253_lock, flags); outb_p(0x00, PIT_MODE); count = inb_p(PIT_CH0); count |= inb_p(PIT_CH0) << 8; spin_unlock_irqrestore(&i8253_lock, flags); return count; } /* next tick in 8254 can be caught by catching timer wraparound */ static void __init wait_8254_wraparound(void) { unsigned int curr_count, prev_count; curr_count = get_8254_timer_count(); do { prev_count = curr_count; curr_count = get_8254_timer_count(); /* workaround for broken Mercury/Neptune */ if (prev_count >= curr_count + 0x100) curr_count = get_8254_timer_count(); } while (prev_count >= curr_count); } /* * Default initialization for 8254 timers. If we use other timers like HPET, * we override this later */ void (*wait_timer_tick)(void) __initdata = wait_8254_wraparound; /* * 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; ver = GET_APIC_VERSION(apic_read(APIC_LVR)); lvtt_value = APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR; if (!APIC_INTEGRATED(ver)) lvtt_value |= SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV); apic_write_around(APIC_LVTT, lvtt_value); /* * Divide PICLK by 16 */ tmp_value = apic_read(APIC_TDCR); apic_write_around(APIC_TDCR, (tmp_value & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE)) | APIC_TDR_DIV_16); apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR); } static void __init setup_APIC_timer(unsigned int clocks) { unsigned long flags; local_irq_save(flags); /* * Wait for IRQ0's slice: */ wait_timer_tick(); __setup_APIC_LVTT(clocks); 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. */ static int __init calibrate_APIC_clock(void) { unsigned long long t1 = 0, t2 = 0; long tt1, tt2; long result; int i; const int LOOPS = HZ/10; apic_printk(APIC_VERBOSE, "calibrating APIC timer ...\n"); /* * 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); /* * The timer chip counts down to zero. Let's wait * for a wraparound to start exact measurement: * (the current tick might have been already half done) */ wait_timer_tick(); /* * We wrapped around just now. Let's start: */ if (cpu_has_tsc) rdtscll(t1); tt1 = apic_read(APIC_TMCCT); /* * Let's wait LOOPS wraprounds: */ for (i = 0; i < LOOPS; i++) wait_timer_tick(); tt2 = apic_read(APIC_TMCCT); if (cpu_has_tsc) rdtscll(t2); /* * The APIC bus clock counter is 32 bits only, it * might have overflown, but note that we use signed * longs, thus no extra care needed. * * underflown to be exact, as the timer counts down ;) */ result = (tt1-tt2)*APIC_DIVISOR/LOOPS; if (cpu_has_tsc) apic_printk(APIC_VERBOSE, "..... CPU clock speed is " "%ld.%04ld MHz.\n", ((long)(t2-t1)/LOOPS)/(1000000/HZ), ((long)(t2-t1)/LOOPS)%(1000000/HZ)); apic_printk(APIC_VERBOSE, "..... host bus clock speed is " "%ld.%04ld MHz.\n", result/(1000000/HZ), result%(1000000/HZ)); return result; } static unsigned int calibration_result; void __init setup_boot_APIC_clock(void) { apic_printk(APIC_VERBOSE, "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 __init setup_secondary_APIC_clock(void) { setup_APIC_timer(calibration_result); } void __init disable_APIC_timer(void) { if (using_apic_timer) { unsigned long v; v = apic_read(APIC_LVTT); apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED); } } void enable_APIC_timer(void) { if (using_apic_timer) { unsigned long v; v = apic_read(APIC_LVTT); apic_write_around(APIC_LVTT, v & ~APIC_LVT_MASKED); } } /* * the frequency of the profiling timer can be changed * by writing a multiplier value into /proc/profile. */ int setup_profiling_timer(unsigned int multiplier) { int i; /* * Sanity check. [at least 500 APIC cycles should be * between APIC interrupts as a rule of thumb, to avoid * irqs flooding us] */ if ( (!multiplier) || (calibration_result/multiplier < 500)) return -EINVAL; /* * Set the new multiplier for each CPU. CPUs don't start using the * new values until the next timer interrupt in which they do process * accounting. At that time they also adjust their APIC timers * accordingly. */ for (i = 0; i < NR_CPUS; ++i) per_cpu(prof_multiplier, i) = multiplier; return 0; } #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. */ inline void smp_local_timer_interrupt(struct pt_regs * regs) { int cpu = smp_processor_id(); profile_tick(CPU_PROFILING, regs); if (--per_cpu(prof_counter, cpu) <= 0) { /* * The multiplier may have changed since the last time we got * to this point as a result of the user writing to * /proc/profile. In this case we need to adjust the APIC * timer accordingly. * * Interrupts are already masked off at this point. */ per_cpu(prof_counter, cpu) = per_cpu(prof_multiplier, cpu); if (per_cpu(prof_counter, cpu) != per_cpu(prof_old_multiplier, cpu)) { __setup_APIC_LVTT( calibration_result/ per_cpu(prof_counter, cpu)); per_cpu(prof_old_multiplier, cpu) = per_cpu(prof_counter, cpu); } #ifdef CONFIG_SMP update_process_times(user_mode(regs)); #endif } /* * We take the 'long' return path, and there every subsystem * grabs the apropriate 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 ... ] */ fastcall void smp_apic_timer_interrupt(struct pt_regs *regs) { int cpu = smp_processor_id(); /* * the NMI deadlock-detector uses this. */ per_cpu(irq_stat, cpu).apic_timer_irqs++; /* * 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. */ irq_enter(); smp_local_timer_interrupt(regs); irq_exit(); } /* * This interrupt should _never_ happen with our APIC/SMP architecture */ fastcall void smp_spurious_interrupt(struct pt_regs *regs) { unsigned long v; 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(); /* see sw-dev-man vol 3, chapter 7.4.13.5 */ printk(KERN_INFO "spurious APIC interrupt on CPU#%d, should never happen.\n", smp_processor_id()); irq_exit(); } /* * This interrupt should never happen with our APIC/SMP architecture */ fastcall void smp_error_interrupt(struct pt_regs *regs) { unsigned long v, v1; 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: %02lx(%02lx)\n", smp_processor_id(), v , v1); irq_exit(); } /* * This initializes the IO-APIC and APIC hardware if this is * a UP kernel. */ int __init APIC_init_uniprocessor (void) { if (enable_local_apic < 0) clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability); if (!smp_found_config && !cpu_has_apic) return -1; /* * Complain if the BIOS pretends there is one. */ if (!cpu_has_apic && APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) { printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n", boot_cpu_physical_apicid); return -1; } verify_local_APIC(); connect_bsp_APIC(); phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid); setup_local_APIC(); if (nmi_watchdog == NMI_LOCAL_APIC) check_nmi_watchdog(); #ifdef CONFIG_X86_IO_APIC if (smp_found_config) if (!skip_ioapic_setup && nr_ioapics) setup_IO_APIC(); #endif setup_boot_APIC_clock(); return 0; }