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/*
* Intel specific MCE features.
* Copyright 2004 Zwane Mwaikambo <zwane@linuxpower.ca>
* Copyright (C) 2008, 2009 Intel Corporation
* Author: Andi Kleen
*/
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/percpu.h>
#include <asm/apic.h>
#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/mce.h>
/*
* Support for Intel Correct Machine Check Interrupts. This allows
* the CPU to raise an interrupt when a corrected machine check happened.
* Normally we pick those up using a regular polling timer.
* Also supports reliable discovery of shared banks.
*/
static DEFINE_PER_CPU(mce_banks_t, mce_banks_owned);
/*
* cmci_discover_lock protects against parallel discovery attempts
* which could race against each other.
*/
static DEFINE_SPINLOCK(cmci_discover_lock);
#define CMCI_THRESHOLD 1
static int cmci_supported(int *banks)
{
u64 cap;
if (mce_cmci_disabled || mce_ignore_ce)
return 0;
/*
* Vendor check is not strictly needed, but the initial
* initialization is vendor keyed and this
* makes sure none of the backdoors are entered otherwise.
*/
if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
return 0;
if (!cpu_has_apic || lapic_get_maxlvt() < 6)
return 0;
rdmsrl(MSR_IA32_MCG_CAP, cap);
*banks = min_t(unsigned, MAX_NR_BANKS, cap & 0xff);
return !!(cap & MCG_CMCI_P);
}
/*
* The interrupt handler. This is called on every event.
* Just call the poller directly to log any events.
* This could in theory increase the threshold under high load,
* but doesn't for now.
*/
static void intel_threshold_interrupt(void)
{
machine_check_poll(MCP_TIMESTAMP, &__get_cpu_var(mce_banks_owned));
mce_notify_irq();
}
static void print_update(char *type, int *hdr, int num)
{
if (*hdr == 0)
printk(KERN_INFO "CPU %d MCA banks", smp_processor_id());
*hdr = 1;
printk(KERN_CONT " %s:%d", type, num);
}
/*
* Enable CMCI (Corrected Machine Check Interrupt) for available MCE banks
* on this CPU. Use the algorithm recommended in the SDM to discover shared
* banks.
*/
static void cmci_discover(int banks, int boot)
{
unsigned long *owned = (void *)&__get_cpu_var(mce_banks_owned);
unsigned long flags;
int hdr = 0;
int i;
spin_lock_irqsave(&cmci_discover_lock, flags);
for (i = 0; i < banks; i++) {
u64 val;
if (test_bit(i, owned))
continue;
rdmsrl(MSR_IA32_MCx_CTL2(i), val);
/* Already owned by someone else? */
if (val & CMCI_EN) {
if (test_and_clear_bit(i, owned) || boot)
print_update("SHD", &hdr, i);
__clear_bit(i, __get_cpu_var(mce_poll_banks));
continue;
}
val |= CMCI_EN | CMCI_THRESHOLD;
wrmsrl(MSR_IA32_MCx_CTL2(i), val);
rdmsrl(MSR_IA32_MCx_CTL2(i), val);
/* Did the enable bit stick? -- the bank supports CMCI */
if (val & CMCI_EN) {
if (!test_and_set_bit(i, owned) || boot)
print_update("CMCI", &hdr, i);
__clear_bit(i, __get_cpu_var(mce_poll_banks));
} else {
WARN_ON(!test_bit(i, __get_cpu_var(mce_poll_banks)));
}
}
spin_unlock_irqrestore(&cmci_discover_lock, flags);
if (hdr)
printk(KERN_CONT "\n");
}
/*
* Just in case we missed an event during initialization check
* all the CMCI owned banks.
*/
void cmci_recheck(void)
{
unsigned long flags;
int banks;
if (!mce_available(¤t_cpu_data) || !cmci_supported(&banks))
return;
local_irq_save(flags);
machine_check_poll(MCP_TIMESTAMP, &__get_cpu_var(mce_banks_owned));
local_irq_restore(flags);
}
/*
* Disable CMCI on this CPU for all banks it owns when it goes down.
* This allows other CPUs to claim the banks on rediscovery.
*/
void cmci_clear(void)
{
unsigned long flags;
int i;
int banks;
u64 val;
if (!cmci_supported(&banks))
return;
spin_lock_irqsave(&cmci_discover_lock, flags);
for (i = 0; i < banks; i++) {
if (!test_bit(i, __get_cpu_var(mce_banks_owned)))
continue;
/* Disable CMCI */
rdmsrl(MSR_IA32_MCx_CTL2(i), val);
val &= ~(CMCI_EN|CMCI_THRESHOLD_MASK);
wrmsrl(MSR_IA32_MCx_CTL2(i), val);
__clear_bit(i, __get_cpu_var(mce_banks_owned));
}
spin_unlock_irqrestore(&cmci_discover_lock, flags);
}
/*
* After a CPU went down cycle through all the others and rediscover
* Must run in process context.
*/
void cmci_rediscover(int dying)
{
int banks;
int cpu;
cpumask_var_t old;
if (!cmci_supported(&banks))
return;
if (!alloc_cpumask_var(&old, GFP_KERNEL))
return;
cpumask_copy(old, ¤t->cpus_allowed);
for_each_online_cpu(cpu) {
if (cpu == dying)
continue;
if (set_cpus_allowed_ptr(current, cpumask_of(cpu)))
continue;
/* Recheck banks in case CPUs don't all have the same */
if (cmci_supported(&banks))
cmci_discover(banks, 0);
}
set_cpus_allowed_ptr(current, old);
free_cpumask_var(old);
}
/*
* Reenable CMCI on this CPU in case a CPU down failed.
*/
void cmci_reenable(void)
{
int banks;
if (cmci_supported(&banks))
cmci_discover(banks, 0);
}
static void intel_init_cmci(void)
{
int banks;
if (!cmci_supported(&banks))
return;
mce_threshold_vector = intel_threshold_interrupt;
cmci_discover(banks, 1);
/*
* For CPU #0 this runs with still disabled APIC, but that's
* ok because only the vector is set up. We still do another
* check for the banks later for CPU #0 just to make sure
* to not miss any events.
*/
apic_write(APIC_LVTCMCI, THRESHOLD_APIC_VECTOR|APIC_DM_FIXED);
cmci_recheck();
}
void mce_intel_feature_init(struct cpuinfo_x86 *c)
{
intel_init_thermal(c);
intel_init_cmci();
}
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