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linux/arch/x86_64/kernel/apic.c

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/*
* 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/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>
#include <asm/nmi.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));
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(int virt_wire_setup)
{
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);
}
else {
/* Go back to Virtual Wire compatibility mode */
unsigned long value;
/* For the spurious interrupt use vector F, and enable it */
value = apic_read(APIC_SPIV);
value &= ~APIC_VECTOR_MASK;
value |= APIC_SPIV_APIC_ENABLED;
value |= 0xf;
apic_write_around(APIC_SPIV, value);
if (!virt_wire_setup) {
/* For LVT0 make it edge triggered, active high, external and enabled */
value = apic_read(APIC_LVT0);
value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT);
apic_write_around(APIC_LVT0, value);
}
else {
/* Disable LVT0 */
apic_write_around(APIC_LVT0, APIC_LVT_MASKED);
}
/* For LVT1 make it edge triggered, active high, nmi and enabled */
value = apic_read(APIC_LVT1);
value &= ~(
APIC_MODE_MASK | APIC_SEND_PENDING |
APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
apic_write_around(APIC_LVT1, value);
}
}
void disable_local_APIC(void)
{
unsigned int value;
clear_local_APIC();
/*
* Disable APIC (implies clearing of registers
* for 82489DX!).
*/
value = apic_read(APIC_SPIV);
value &= ~APIC_SPIV_APIC_ENABLED;
apic_write_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;
apic_write_around(APIC_LVT1, value);
}
void __cpuinit setup_local_APIC (void)
{
unsigned int value, ver, maxlvt;
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;
apic_write_around(APIC_LVT1, value);
{
unsigned oldvalue;
maxlvt = get_maxlvt();
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);
}
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, 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_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 __cpuinit apic_pm_activate(void)
{
apic_pm_state.active = 1;
}
static int __init init_lapic_sysfs(void)
{
int error;
if (!cpu_has_apic)
return 0;
/* XXX: remove suspend/resume procs if !apic_pm_state.active? */
error = sysdev_class_register(&lapic_sysclass);
if (!error)
error = sysdev_register(&device_lapic);
return error;
}
device_initcall(init_lapic_sysfs);
#else /* CONFIG_PM */
static void apic_pm_activate(void) { }
#endif /* CONFIG_PM */
static int __init apic_set_verbosity(char *str)
{
if (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).
*/
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;
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 __cpuinit setup_secondary_APIC_clock(void)
{
local_irq_disable(); /* FIXME: Do we need this? --RR */
setup_APIC_timer(calibration_result);
local_irq_enable();
}
void __cpuinit 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_zero(clustermap, NUM_APIC_CLUSTERS);
for (i = 0; i < NR_CPUS; i++) {
id = bios_cpu_apicid[i];
if (id != BAD_APICID)
__set_bit(APIC_CLUSTERID(id), clustermap);
}
/* Problem: Partially populated chassis may not have CPUs in some of
* the APIC clusters they have been allocated. Only present CPUs have
* bios_cpu_apicid entries, thus causing zeroes in the bitmap. Since
* clusters are allocated sequentially, count zeros only if they are
* bounded by ones.
*/
clusters = 0;
zeros = 0;
for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
if (test_bit(i, clustermap)) {
clusters += 1 + zeros;
zeros = 0;
} else
++zeros;
}
/*
* If clusters > 2, then should be multi-chassis. 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(boot_cpu_id);
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();
check_nmi_watchdog();
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. */
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