From 9a8b4584065dd241d6c2bf818e349986bd900b8e Mon Sep 17 00:00:00 2001
From: James Bottomley <jejb@parisc-linux.org>
Date: Thu, 17 Nov 2005 16:24:52 -0500
Subject: [PATCH] [PARISC] Make sure timer and IPI execute with interrupts
disabled
Fix a longstanding smp bug
The problem is that both the timer and ipi interrupts are being called
with interrupts enabled, which isn't what anyone is expecting.
The IPI issue has just started to show up by causing a BUG_ON in the
slab debugging code. The timer issue never shows up because there's an
eiem work around in our irq.c
The fix is to label both these as SA_INTERRUPT which causes the generic
irq code not to enable interrupts.
I also suspect the smp_call_function timeouts we're seeing might be
connected with the fact that we disable IPIs when handling any other
type of interrupt. I've put a WARN_ON in the code for executing
smp_call_function() with IPIs disabled.
Signed-off-by: James Bottomley <jejb@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
---
arch/parisc/kernel/irq.c | 2 ++
arch/parisc/kernel/smp.c | 4 ++++
2 files changed, 6 insertions(+)
diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index 006385dbee660..f7ae2bcd49a57 100644
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c
@@ -291,12 +291,14 @@ void do_cpu_irq_mask(struct pt_regs *regs)
static struct irqaction timer_action = {
.handler = timer_interrupt,
.name = "timer",
+ .flags = SA_INTERRUPT,
};
#ifdef CONFIG_SMP
static struct irqaction ipi_action = {
.handler = ipi_interrupt,
.name = "IPI",
+ .flags = SA_INTERRUPT,
};
#endif
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index a9ecf6465784e..268b0f2a328eb 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -338,6 +338,10 @@ smp_call_function (void (*func) (void *info), void *info, int retry, int wait)
/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
+
+ /* can also deadlock if IPIs are disabled */
+ WARN_ON((get_eiem() & (1UL<<(CPU_IRQ_MAX - IPI_IRQ))) == 0);
+
data.func = func;
data.info = info;
--
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