linux/arch/ia64/kernel/irq.c
Magnus Damm 29a002776b [PATCH] kexec: Avoid migration of already disabled irqs (ia64)
This patch fixes up ia64 kexec support for HP rx2620 hardware.  It does
this by skipping migration of already disabled irqs.  This is most likely a
problem on other ia64 platforms as well, but I've only been able to
reproduce it on one machine so far.

The full story is that handle_bad_irq() gets invoked before starting the
new kernel without this patch.  This seems to happen when fixup_irqs()
calls generic_handle_irq() on already migrated (and disabled) irqs.  So by
avoiding migration of disabled irqs we stay away of handle_bad_irq().

The code has been tested on three different ia64 machines, all with good
results.  It is possible to trigger the same bug by offlining a processor
using echo 0 > /sys/devices/system/cpu/cpuX/online.

More detailed information is available in the following mail thread:
http://lists.osdl.org/pipermail/fastboot/2007-January/thread.html#5774

Signed-off-by: Magnus Damm <magnus@valinux.co.jp>
Acked-by: Simon Horman <horms@verge.net.au>
Acked-by: Zou, Nanhai <nanhai.zou@intel.com>
Acked-by: Jay Lan <jlan@sgi.com>
Acked-by: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-03 11:26:06 -08:00

217 lines
5.1 KiB
C

/*
* linux/arch/ia64/kernel/irq.c
*
* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
*
* 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.
*
* Copyright (C) Ashok Raj<ashok.raj@intel.com>, Intel Corporation 2004
*
* 4/14/2004: Added code to handle cpu migration and do safe irq
* migration without lossing interrupts for iosapic
* architecture.
*/
#include <asm/delay.h>
#include <asm/uaccess.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
/*
* '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)
{
printk(KERN_ERR "Unexpected irq vector 0x%x on CPU %u!\n", irq, smp_processor_id());
}
#ifdef CONFIG_IA64_GENERIC
unsigned int __ia64_local_vector_to_irq (ia64_vector vec)
{
return (unsigned int) vec;
}
#endif
/*
* Interrupt statistics:
*/
atomic_t irq_err_count;
/*
* /proc/interrupts printing:
*/
int show_interrupts(struct seq_file *p, void *v)
{
int i = *(loff_t *) v, j;
struct irqaction * action;
unsigned long flags;
if (i == 0) {
seq_printf(p, " ");
for_each_online_cpu(j) {
seq_printf(p, "CPU%d ",j);
}
seq_putc(p, '\n');
}
if (i < NR_IRQS) {
spin_lock_irqsave(&irq_desc[i].lock, flags);
action = irq_desc[i].action;
if (!action)
goto skip;
seq_printf(p, "%3d: ",i);
#ifndef CONFIG_SMP
seq_printf(p, "%10u ", kstat_irqs(i));
#else
for_each_online_cpu(j) {
seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
}
#endif
seq_printf(p, " %14s", irq_desc[i].chip->name);
seq_printf(p, " %s", action->name);
for (action=action->next; action; action = action->next)
seq_printf(p, ", %s", action->name);
seq_putc(p, '\n');
skip:
spin_unlock_irqrestore(&irq_desc[i].lock, flags);
} else if (i == NR_IRQS)
seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
return 0;
}
#ifdef CONFIG_SMP
static char irq_redir [NR_IRQS]; // = { [0 ... NR_IRQS-1] = 1 };
void set_irq_affinity_info (unsigned int irq, int hwid, int redir)
{
cpumask_t mask = CPU_MASK_NONE;
cpu_set(cpu_logical_id(hwid), mask);
if (irq < NR_IRQS) {
irq_desc[irq].affinity = mask;
irq_redir[irq] = (char) (redir & 0xff);
}
}
#endif /* CONFIG_SMP */
#ifdef CONFIG_HOTPLUG_CPU
unsigned int vectors_in_migration[NR_IRQS];
/*
* Since cpu_online_map is already updated, we just need to check for
* affinity that has zeros
*/
static void migrate_irqs(void)
{
cpumask_t mask;
irq_desc_t *desc;
int irq, new_cpu;
for (irq=0; irq < NR_IRQS; irq++) {
desc = irq_desc + irq;
if (desc->status == IRQ_DISABLED)
continue;
/*
* No handling for now.
* TBD: Implement a disable function so we can now
* tell CPU not to respond to these local intr sources.
* such as ITV,CPEI,MCA etc.
*/
if (desc->status == IRQ_PER_CPU)
continue;
cpus_and(mask, irq_desc[irq].affinity, cpu_online_map);
if (any_online_cpu(mask) == NR_CPUS) {
/*
* Save it for phase 2 processing
*/
vectors_in_migration[irq] = irq;
new_cpu = any_online_cpu(cpu_online_map);
mask = cpumask_of_cpu(new_cpu);
/*
* Al three are essential, currently WARN_ON.. maybe panic?
*/
if (desc->chip && desc->chip->disable &&
desc->chip->enable && desc->chip->set_affinity) {
desc->chip->disable(irq);
desc->chip->set_affinity(irq, mask);
desc->chip->enable(irq);
} else {
WARN_ON((!(desc->chip) || !(desc->chip->disable) ||
!(desc->chip->enable) ||
!(desc->chip->set_affinity)));
}
}
}
}
void fixup_irqs(void)
{
unsigned int irq;
extern void ia64_process_pending_intr(void);
extern void ia64_disable_timer(void);
extern volatile int time_keeper_id;
ia64_disable_timer();
/*
* Find a new timesync master
*/
if (smp_processor_id() == time_keeper_id) {
time_keeper_id = first_cpu(cpu_online_map);
printk ("CPU %d is now promoted to time-keeper master\n", time_keeper_id);
}
/*
* Phase 1: Locate irq's bound to this cpu and
* relocate them for cpu removal.
*/
migrate_irqs();
/*
* Phase 2: Perform interrupt processing for all entries reported in
* local APIC.
*/
ia64_process_pending_intr();
/*
* Phase 3: Now handle any interrupts not captured in local APIC.
* This is to account for cases that device interrupted during the time the
* rte was being disabled and re-programmed.
*/
for (irq=0; irq < NR_IRQS; irq++) {
if (vectors_in_migration[irq]) {
struct pt_regs *old_regs = set_irq_regs(NULL);
vectors_in_migration[irq]=0;
generic_handle_irq(irq);
set_irq_regs(old_regs);
}
}
/*
* Now let processor die. We do irq disable and max_xtp() to
* ensure there is no more interrupts routed to this processor.
* But the local timer interrupt can have 1 pending which we
* take care in timer_interrupt().
*/
max_xtp();
local_irq_disable();
}
#endif