kernel_optimize_test/arch/x86/kernel/irq.c
Liu, Chuansheng 99dd5497e5 x86: Preserve lazy irq disable semantics in fixup_irqs()
The default irq_disable() sematics are to mark the interrupt disabled,
but keep it unmasked. If the interrupt is delivered while marked
disabled, the low level interrupt handler masks it and marks it
pending. This is important for detecting wakeup interrupts during
suspend and for edge type interrupts to avoid losing interrupts.

fixup_irqs() moves the interrupts away from an offlined cpu. For
certain interrupt types it needs to mask the interrupt line before
changing the affinity. After affinity has changed the interrupt line
is unmasked again, but only if it is not marked disabled.

This breaks the lazy irq disable semantics and causes problems in
suspend as the interrupt can be lost or wakeup functionality is
broken.

Check irqd_irq_masked() instead of irqd_irq_disabled() because
irqd_irq_masked() is only set, when the core code actually masked the
interrupt line. If it's not set, we unmask the interrupt and let the
lazy irq disable logic deal with an eventually incoming interrupt.

[ tglx: Massaged changelog and added a comment ]

Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Link: http://lkml.kernel.org/r/27240C0AC20F114CBF8149A2696CBE4A05DFB3@SHSMSX101.ccr.corp.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-29 15:28:47 +02:00

334 lines
8.7 KiB
C

/*
* Common interrupt code for 32 and 64 bit
*/
#include <linux/cpu.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/of.h>
#include <linux/seq_file.h>
#include <linux/smp.h>
#include <linux/ftrace.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <asm/apic.h>
#include <asm/io_apic.h>
#include <asm/irq.h>
#include <asm/idle.h>
#include <asm/mce.h>
#include <asm/hw_irq.h>
atomic_t irq_err_count;
/* Function pointer for generic interrupt vector handling */
void (*x86_platform_ipi_callback)(void) = NULL;
/*
* '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)
{
if (printk_ratelimit())
pr_err("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.
* But only ack when the APIC is enabled -AK
*/
ack_APIC_irq();
}
#define irq_stats(x) (&per_cpu(irq_stat, x))
/*
* /proc/interrupts printing for arch specific interrupts
*/
int arch_show_interrupts(struct seq_file *p, int prec)
{
int j;
seq_printf(p, "%*s: ", prec, "NMI");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->__nmi_count);
seq_printf(p, " Non-maskable interrupts\n");
#ifdef CONFIG_X86_LOCAL_APIC
seq_printf(p, "%*s: ", prec, "LOC");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->apic_timer_irqs);
seq_printf(p, " Local timer interrupts\n");
seq_printf(p, "%*s: ", prec, "SPU");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_spurious_count);
seq_printf(p, " Spurious interrupts\n");
seq_printf(p, "%*s: ", prec, "PMI");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->apic_perf_irqs);
seq_printf(p, " Performance monitoring interrupts\n");
seq_printf(p, "%*s: ", prec, "IWI");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->apic_irq_work_irqs);
seq_printf(p, " IRQ work interrupts\n");
seq_printf(p, "%*s: ", prec, "RTR");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->icr_read_retry_count);
seq_printf(p, " APIC ICR read retries\n");
#endif
if (x86_platform_ipi_callback) {
seq_printf(p, "%*s: ", prec, "PLT");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->x86_platform_ipis);
seq_printf(p, " Platform interrupts\n");
}
#ifdef CONFIG_SMP
seq_printf(p, "%*s: ", prec, "RES");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
seq_printf(p, " Rescheduling interrupts\n");
seq_printf(p, "%*s: ", prec, "CAL");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_call_count);
seq_printf(p, " Function call interrupts\n");
seq_printf(p, "%*s: ", prec, "TLB");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
seq_printf(p, " TLB shootdowns\n");
#endif
#ifdef CONFIG_X86_THERMAL_VECTOR
seq_printf(p, "%*s: ", prec, "TRM");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
seq_printf(p, " Thermal event interrupts\n");
#endif
#ifdef CONFIG_X86_MCE_THRESHOLD
seq_printf(p, "%*s: ", prec, "THR");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
seq_printf(p, " Threshold APIC interrupts\n");
#endif
#ifdef CONFIG_X86_MCE
seq_printf(p, "%*s: ", prec, "MCE");
for_each_online_cpu(j)
seq_printf(p, "%10u ", per_cpu(mce_exception_count, j));
seq_printf(p, " Machine check exceptions\n");
seq_printf(p, "%*s: ", prec, "MCP");
for_each_online_cpu(j)
seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
seq_printf(p, " Machine check polls\n");
#endif
seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
#if defined(CONFIG_X86_IO_APIC)
seq_printf(p, "%*s: %10u\n", prec, "MIS", atomic_read(&irq_mis_count));
#endif
return 0;
}
/*
* /proc/stat helpers
*/
u64 arch_irq_stat_cpu(unsigned int cpu)
{
u64 sum = irq_stats(cpu)->__nmi_count;
#ifdef CONFIG_X86_LOCAL_APIC
sum += irq_stats(cpu)->apic_timer_irqs;
sum += irq_stats(cpu)->irq_spurious_count;
sum += irq_stats(cpu)->apic_perf_irqs;
sum += irq_stats(cpu)->apic_irq_work_irqs;
sum += irq_stats(cpu)->icr_read_retry_count;
#endif
if (x86_platform_ipi_callback)
sum += irq_stats(cpu)->x86_platform_ipis;
#ifdef CONFIG_SMP
sum += irq_stats(cpu)->irq_resched_count;
sum += irq_stats(cpu)->irq_call_count;
sum += irq_stats(cpu)->irq_tlb_count;
#endif
#ifdef CONFIG_X86_THERMAL_VECTOR
sum += irq_stats(cpu)->irq_thermal_count;
#endif
#ifdef CONFIG_X86_MCE_THRESHOLD
sum += irq_stats(cpu)->irq_threshold_count;
#endif
#ifdef CONFIG_X86_MCE
sum += per_cpu(mce_exception_count, cpu);
sum += per_cpu(mce_poll_count, cpu);
#endif
return sum;
}
u64 arch_irq_stat(void)
{
u64 sum = atomic_read(&irq_err_count);
#ifdef CONFIG_X86_IO_APIC
sum += atomic_read(&irq_mis_count);
#endif
return sum;
}
/*
* do_IRQ handles all normal device IRQ's (the special
* SMP cross-CPU interrupts have their own specific
* handlers).
*/
unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
/* high bit used in ret_from_ code */
unsigned vector = ~regs->orig_ax;
unsigned irq;
irq_enter();
exit_idle();
irq = __this_cpu_read(vector_irq[vector]);
if (!handle_irq(irq, regs)) {
ack_APIC_irq();
if (printk_ratelimit())
pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n",
__func__, smp_processor_id(), vector, irq);
}
irq_exit();
set_irq_regs(old_regs);
return 1;
}
/*
* Handler for X86_PLATFORM_IPI_VECTOR.
*/
void smp_x86_platform_ipi(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
ack_APIC_irq();
irq_enter();
exit_idle();
inc_irq_stat(x86_platform_ipis);
if (x86_platform_ipi_callback)
x86_platform_ipi_callback();
irq_exit();
set_irq_regs(old_regs);
}
EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
#ifdef CONFIG_HOTPLUG_CPU
/* A cpu has been removed from cpu_online_mask. Reset irq affinities. */
void fixup_irqs(void)
{
unsigned int irq, vector;
static int warned;
struct irq_desc *desc;
struct irq_data *data;
struct irq_chip *chip;
for_each_irq_desc(irq, desc) {
int break_affinity = 0;
int set_affinity = 1;
const struct cpumask *affinity;
if (!desc)
continue;
if (irq == 2)
continue;
/* interrupt's are disabled at this point */
raw_spin_lock(&desc->lock);
data = irq_desc_get_irq_data(desc);
affinity = data->affinity;
if (!irq_has_action(irq) || irqd_is_per_cpu(data) ||
cpumask_subset(affinity, cpu_online_mask)) {
raw_spin_unlock(&desc->lock);
continue;
}
/*
* Complete the irq move. This cpu is going down and for
* non intr-remapping case, we can't wait till this interrupt
* arrives at this cpu before completing the irq move.
*/
irq_force_complete_move(irq);
if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
break_affinity = 1;
affinity = cpu_all_mask;
}
chip = irq_data_get_irq_chip(data);
if (!irqd_can_move_in_process_context(data) && chip->irq_mask)
chip->irq_mask(data);
if (chip->irq_set_affinity)
chip->irq_set_affinity(data, affinity, true);
else if (!(warned++))
set_affinity = 0;
/*
* We unmask if the irq was not marked masked by the
* core code. That respects the lazy irq disable
* behaviour.
*/
if (!irqd_can_move_in_process_context(data) &&
!irqd_irq_masked(data) && chip->irq_unmask)
chip->irq_unmask(data);
raw_spin_unlock(&desc->lock);
if (break_affinity && set_affinity)
printk("Broke affinity for irq %i\n", irq);
else if (!set_affinity)
printk("Cannot set affinity for irq %i\n", irq);
}
/*
* We can remove mdelay() and then send spuriuous interrupts to
* new cpu targets for all the irqs that were handled previously by
* this cpu. While it works, I have seen spurious interrupt messages
* (nothing wrong but still...).
*
* So for now, retain mdelay(1) and check the IRR and then send those
* interrupts to new targets as this cpu is already offlined...
*/
mdelay(1);
for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
unsigned int irr;
if (__this_cpu_read(vector_irq[vector]) < 0)
continue;
irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
if (irr & (1 << (vector % 32))) {
irq = __this_cpu_read(vector_irq[vector]);
desc = irq_to_desc(irq);
data = irq_desc_get_irq_data(desc);
chip = irq_data_get_irq_chip(data);
raw_spin_lock(&desc->lock);
if (chip->irq_retrigger)
chip->irq_retrigger(data);
raw_spin_unlock(&desc->lock);
}
}
}
#endif