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, 1088 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
new file mode 100644
index 000000000000..9826f03dc9a3
--- /dev/null
+++ b/arch/x86_64/kernel/apic.c
@@ -0,0 +1,1088 @@
+/*
+ *	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/pgalloc.h>
+#include <asm/mach_apic.h>
+
+int apic_verbosity;
+
+int disable_apic_timer __initdata;
+
+/* 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 void apic_pm_activate(void);
+
+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 */
+	apic_write_around(APIC_LVT0, v);
+}
+
+int get_maxlvt(void)
+{
+	unsigned int v, ver, maxlvt;
+
+	v = apic_read(APIC_LVR);
+	ver = GET_APIC_VERSION(v);
+	maxlvt = GET_APIC_MAXLVT(v);
+	return maxlvt;
+}
+
+void clear_local_APIC(void)
+{
+	int maxlvt;
+	unsigned int 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);
+	}
+
+	/*
+	 * 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);
+	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);
+	}
+}
+
+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_QUIET, "disabling APIC mode, entering PIC mode.\n");
+		outb(0x70, 0x22);
+		outb(0x00, 0x23);
+	}
+}
+
+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_around(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_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 int 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;
+	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 int 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.
+	 * 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_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 necessary 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 */
+		unsigned oldvalue;
+		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 after enabling vector: %08x, after %08x\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
+			 */
+			apic_printk(APIC_DEBUG, "Leaving ESR disabled.\n");
+		else 
+			apic_printk(APIC_DEBUG, "No ESR for 82489DX.\n");
+	}
+
+	nmi_watchdog_default();
+	if (nmi_watchdog == NMI_LOCAL_APIC)
+		setup_apic_nmi_watchdog();
+	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, 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_save_flags(flags);
+	local_irq_disable();
+	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;
+
+	/* XXX: Pavel needs this for S3 resume, but can't explain why */
+	set_fixmap_nocache(FIX_APIC_BASE, APIC_DEFAULT_PHYS_BASE);
+
+	local_irq_save(flags);
+	rdmsr(MSR_IA32_APICBASE, l, h);
+	l &= ~MSR_IA32_APICBASE_BASE;
+	l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
+	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 __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 */
+
+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);
+
+/*
+ * 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_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).
+	 */
+	if (boot_cpu_id == -1U)
+		boot_cpu_id = 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;
+			} 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++;
+		}
+	}
+#endif
+}
+
+/*
+ * 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 setup_APIC_timer(unsigned int clocks)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	/* For some reasons this doesn't work on Simics, so fake it for now */ 
+	if (!strstr(boot_cpu_data.x86_model_id, "Screwdriver")) { 
+	__setup_APIC_LVTT(clocks);
+		return;
+	} 
+
+	/* wait for irq slice */
+ 	if (vxtime.hpet_address) {
+ 		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);
+
+	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);
+	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(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 __init setup_secondary_APIC_clock(void)
+{
+	local_irq_disable(); /* FIXME: Do we need this? --RR */
+	setup_APIC_timer(calibration_result);
+	local_irq_enable();
+}
+
+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.
+ */
+
+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 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(struct pt_regs *regs)
+{
+	/*
+	 * 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.
+	 */
+	irq_enter();
+	smp_local_timer_interrupt(regs);
+	irq_exit();
+}
+
+/*
+ * oem_force_hpet_timer -- force HPET mode for some boxes.
+ *
+ * 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.
+ */
+__init int oem_force_hpet_timer(void)
+{
+	int i, clusters, zeros;
+	unsigned id;
+	DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);
+
+	bitmap_empty(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.  Return 1 for HPET.
+	 * Else return 0 to use TSC.
+	 * 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;
+	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;
+
+	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();
+
+	connect_bsp_APIC();
+
+	phys_cpu_present_map = physid_mask_of_physid(0);
+	apic_write_around(APIC_ID, boot_cpu_id);
+
+	setup_local_APIC();
+
+#ifdef CONFIG_X86_IO_APIC
+	if (smp_found_config && !skip_ioapic_setup && nr_ioapics)
+			setup_IO_APIC();
+	else
+		nr_ioapics = 0;
+#endif
+	setup_boot_APIC_clock();
+
+	return 0;
+}
+
+static __init int setup_disableapic(char *str) 
+{ 
+	disable_apic = 1;
+	return 0;
+} 
+
+static __init int setup_nolapic(char *str) 
+{ 
+	disable_apic = 1;
+	return 0;
+} 
+
+static __init int setup_noapictimer(char *str) 
+{ 
+	disable_apic_timer = 1;
+	return 0;
+} 
+
+/* dummy parsing: see setup.c */
+
+__setup("disableapic", setup_disableapic); 
+__setup("nolapic", setup_nolapic);  /* same as disableapic, for compatibility */
+
+__setup("noapictimer", setup_noapictimer); 
+
+/* no "lapic" flag - we only use the lapic when the BIOS tells us so. */