Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1278 insertions, 0 deletions

diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
new file mode 100644
index 000000000000..35c1751ea0b0
--- /dev/null
+++ b/arch/i386/kernel/apic.c
@@ -0,0 +1,1278 @@
+/*
+ *      Local APIC handling, local APIC timers
+ *
+ *      (c) 1999, 2000 Ingo Molnar <mingo@redhat.com>
+ *
+ *      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 <linux/config.h>
+#include <linux/init.h>
+
+#include <linux/mm.h>
+#include <linux/irq.h>
+#include <linux/delay.h>
+#include <linux/bootmem.h>
+#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+#include <linux/mc146818rtc.h>
+#include <linux/kernel_stat.h>
+#include <linux/sysdev.h>
+
+#include <asm/atomic.h>
+#include <asm/smp.h>
+#include <asm/mtrr.h>
+#include <asm/mpspec.h>
+#include <asm/desc.h>
+#include <asm/arch_hooks.h>
+#include <asm/hpet.h>
+
+#include <mach_apic.h>
+
+#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, u32 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;
+}