linux-stable/arch/alpha/kernel/irq.c
Will Deacon e20800fd5c alpha: irq: run all handlers with interrupts disabled
Linux has expected that interrupt handlers are executed with local
interrupts disabled for a while now, so ensure that this is the case on
Alpha even for non-device interrupts such as IPIs.

Without this patch, secondary boot results in the following backtrace:

  warning: at kernel/softirq.c:139 __local_bh_enable+0xb8/0xd0()
  trace:
    __local_bh_enable+0xb8/0xd0
    irq_enter+0x74/0xa0
    scheduler_ipi+0x50/0x100
    handle_ipi+0x84/0x260
    do_entint+0x1ac/0x2e0
    irq_exit+0x60/0xa0
    handle_irq+0x98/0x100
    do_entint+0x2c8/0x2e0
    ret_from_sys_call+0x0/0x10
    load_balance+0x3e4/0x870
    cpu_idle+0x24/0x80
    rcu_eqs_enter_common.isra.38+0x0/0x120
    cpu_idle+0x40/0x80
    rest_init+0xc0/0xe0
    _stext+0x1c/0x20

A similar dump occurs if you try to reboot using magic-sysrq.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-07 12:59:30 -07:00

123 lines
3 KiB
C

/*
* linux/arch/alpha/kernel/irq.c
*
* Copyright (C) 1995 Linus Torvalds
*
* This file contains the code used by various IRQ handling routines:
* asking for different IRQ's should be done through these routines
* instead of just grabbing them. Thus setups with different IRQ numbers
* shouldn't result in any weird surprises, and installing new handlers
* should be easier.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/interrupt.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/profile.h>
#include <linux/bitops.h>
#include <asm/io.h>
#include <asm/uaccess.h>
volatile unsigned long irq_err_count;
DEFINE_PER_CPU(unsigned long, irq_pmi_count);
void ack_bad_irq(unsigned int irq)
{
irq_err_count++;
printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
}
#ifdef CONFIG_SMP
static char irq_user_affinity[NR_IRQS];
int irq_select_affinity(unsigned int irq)
{
struct irq_data *data = irq_get_irq_data(irq);
struct irq_chip *chip;
static int last_cpu;
int cpu = last_cpu + 1;
if (!data)
return 1;
chip = irq_data_get_irq_chip(data);
if (!chip->irq_set_affinity || irq_user_affinity[irq])
return 1;
while (!cpu_possible(cpu) ||
!cpumask_test_cpu(cpu, irq_default_affinity))
cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
last_cpu = cpu;
cpumask_copy(data->affinity, cpumask_of(cpu));
chip->irq_set_affinity(data, cpumask_of(cpu), false);
return 0;
}
#endif /* CONFIG_SMP */
int arch_show_interrupts(struct seq_file *p, int prec)
{
int j;
#ifdef CONFIG_SMP
seq_puts(p, "IPI: ");
for_each_online_cpu(j)
seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
seq_putc(p, '\n');
#endif
seq_puts(p, "PMI: ");
for_each_online_cpu(j)
seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
seq_puts(p, " Performance Monitoring\n");
seq_printf(p, "ERR: %10lu\n", irq_err_count);
return 0;
}
/*
* handle_irq handles all normal device IRQ's (the special
* SMP cross-CPU interrupts have their own specific
* handlers).
*/
#define MAX_ILLEGAL_IRQS 16
void
handle_irq(int irq)
{
/*
* We ack quickly, we don't want the irq controller
* thinking we're snobs just because some other CPU has
* disabled global interrupts (we have already done the
* INT_ACK cycles, it's too late to try to pretend to the
* controller that we aren't taking the interrupt).
*
* 0 return value means that this irq is already being
* handled by some other CPU. (or is disabled)
*/
static unsigned int illegal_count=0;
struct irq_desc *desc = irq_to_desc(irq);
if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
illegal_count < MAX_ILLEGAL_IRQS)) {
irq_err_count++;
illegal_count++;
printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
irq);
return;
}
irq_enter();
generic_handle_irq_desc(irq, desc);
irq_exit();
}