* PATCH: prototype "handle broken IRQ routing" patch
@ 2004-09-02 20:16 Alan Cox
2004-09-02 20:38 ` Nathan Bryant
0 siblings, 1 reply; 2+ messages in thread
From: Alan Cox @ 2004-09-02 20:16 UTC (permalink / raw)
To: linux-kernel
This works a treat on several boxes that otherwise simply won't run Linux
in any useful form. The theory is simple - if an IRQ is delivered to the wrong
place then someone somewhere in our IRQ handler lists knows what to do with it.
Its if(1) for now, obviously its a boot option and if(my_computer_sucks) in
a final version.
diff -u --new-file --recursive --exclude-from /usr/src/exclude linux-2.6.8.1/arch/i386/kernel/irq.c linux-2.6.8.1.ac/arch/i386/kernel/irq.c
--- linux-2.6.8.1/arch/i386/kernel/irq.c 2004-08-14 11:54:48.000000000 +0100
+++ linux-2.6.8.1.ac/arch/i386/kernel/irq.c 2004-09-03 09:15:17.000000000 +0100
@@ -280,6 +280,38 @@
__setup("noirqdebug", noirqdebug_setup);
/*
+ * Recovery handler for misrouted interrupts
+ */
+
+static int misrouted_irq(int irq, irq_desc_t *desc, struct pt_regs *regs)
+{
+ int i;
+ for(i = 1; i < NR_IRQS; i++)
+ {
+ struct irqaction *action;
+ if(i == irq) /* Already tried */
+ continue;
+ spin_lock(&irq_desc[i].lock);
+ if(irq_desc[i].status & IRQ_INPROGRESS)
+ {
+ spin_unlock(&irq_desc[i].lock);
+ continue;
+ }
+ action = irq_desc[i].action;
+ while(action)
+ {
+ if(action->flags & SA_SHIRQ)
+ {
+ if(action->handler(irq, action->dev_id, regs) == IRQ_HANDLED)
+ desc->irqs_unhandled = 0;
+ }
+ action = action->next;
+ }
+ spin_unlock(&irq_desc[i].lock);
+ }
+}
+
+/*
* If 99,900 of the previous 100,000 interrupts have not been handled then
* assume that the IRQ is stuck in some manner. Drop a diagnostic and try to
* turn the IRQ off.
@@ -289,13 +321,68 @@
*
* Called under desc->lock
*/
-static void note_interrupt(int irq, irq_desc_t *desc, irqreturn_t action_ret)
+static void note_interrupt(int irq, irq_desc_t *desc, irqreturn_t action_ret, struct pt_regs *regs)
{
if (action_ret != IRQ_HANDLED) {
desc->irqs_unhandled++;
if (action_ret != IRQ_NONE)
report_bad_irq(irq, desc, action_ret);
}
+ if(1)
+ {
+#ifdef CONFIG_4KSTACKS
+ irqreturn_t action_ret;
+ u32 *isp;
+ union irq_ctx * curctx;
+ union irq_ctx * irqctx;
+
+ curctx = (union irq_ctx *) current_thread_info();
+ irqctx = hardirq_ctx[smp_processor_id()];
+
+ spin_unlock(&desc->lock);
+
+ /*
+ * this is where we switch to the IRQ stack. However, if we are already using
+ * the IRQ stack (because we interrupted a hardirq handler) we can't do that
+ * and just have to keep using the current stack (which is the irq stack already
+ * after all)
+ */
+
+ if (curctx == irqctx)
+ misrouted_irq(irq, desc, regs);
+ else {
+ /* build the stack frame on the IRQ stack */
+ isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
+ irqctx->tinfo.task = curctx->tinfo.task;
+ irqctx->tinfo.previous_esp = current_stack_pointer();
+
+ *--isp = (u32) regs;
+ *--isp = (u32) desc;
+ *--isp = (u32) irq;
+
+ asm volatile(
+ " xchgl %%ebx,%%esp \n"
+ " call misrouted_irq \n"
+ " xchgl %%ebx,%%esp \n"
+ : "=a"(action_ret)
+ : "b"(isp)
+ : "memory", "cc", "edx", "ecx"
+ );
+
+
+ }
+ spin_lock(&desc->lock);
+ if (curctx != irqctx)
+ irqctx->tinfo.task = NULL;
+#else
+ irqreturn_t action_ret;
+ spin_unlock(&desc->lock);
+
+ misrouted_irq(irq, desc, regs);
+
+ spin_lock(&desc->lock);
+#endif
+ }
desc->irq_count++;
if (desc->irq_count < 100000)
@@ -487,7 +574,7 @@
* useful for irq hardware that does not mask cleanly in an
* SMP environment.
*/
-#ifdef CONFIG_4KSTACKS
+ #ifdef CONFIG_4KSTACKS
for (;;) {
irqreturn_t action_ret;
@@ -532,7 +619,7 @@
}
spin_lock(&desc->lock);
if (!noirqdebug)
- note_interrupt(irq, desc, action_ret);
+ note_interrupt(irq, desc, action_ret, ®s);
if (curctx != irqctx)
irqctx->tinfo.task = NULL;
if (likely(!(desc->status & IRQ_PENDING)))
@@ -551,7 +638,7 @@
spin_lock(&desc->lock);
if (!noirqdebug)
- note_interrupt(irq, desc, action_ret);
+ note_interrupt(irq, desc, action_ret, ®s);
if (likely(!(desc->status & IRQ_PENDING)))
break;
desc->status &= ~IRQ_PENDING;
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: PATCH: prototype "handle broken IRQ routing" patch
2004-09-02 20:16 PATCH: prototype "handle broken IRQ routing" patch Alan Cox
@ 2004-09-02 20:38 ` Nathan Bryant
0 siblings, 0 replies; 2+ messages in thread
From: Nathan Bryant @ 2004-09-02 20:38 UTC (permalink / raw)
To: Alan Cox; +Cc: kernel list
Alan Cox wrote:
> This works a treat on several boxes that otherwise simply won't run Linux
> in any useful form. The theory is simple - if an IRQ is delivered to the wrong
> place then someone somewhere in our IRQ handler lists knows what to do with it.
Wow, this is a crime against humanity! Good job.
There is one problem, it doesn't increment irqs_unhandled when nobody
handled anything. I'm sure these broken boxes are still capable of
having screaming interrupts too ;)
>
> Its if(1) for now, obviously its a boot option and if(my_computer_sucks) in
> a final version.
>
>
> diff -u --new-file --recursive --exclude-from /usr/src/exclude linux-2.6.8.1/arch/i386/kernel/irq.c linux-2.6.8.1.ac/arch/i386/kernel/irq.c
> --- linux-2.6.8.1/arch/i386/kernel/irq.c 2004-08-14 11:54:48.000000000 +0100
> +++ linux-2.6.8.1.ac/arch/i386/kernel/irq.c 2004-09-03 09:15:17.000000000 +0100
> @@ -280,6 +280,38 @@
> __setup("noirqdebug", noirqdebug_setup);
>
> /*
> + * Recovery handler for misrouted interrupts
> + */
> +
> +static int misrouted_irq(int irq, irq_desc_t *desc, struct pt_regs *regs)
> +{
> + int i;
> + for(i = 1; i < NR_IRQS; i++)
> + {
> + struct irqaction *action;
> + if(i == irq) /* Already tried */
> + continue;
> + spin_lock(&irq_desc[i].lock);
> + if(irq_desc[i].status & IRQ_INPROGRESS)
> + {
> + spin_unlock(&irq_desc[i].lock);
> + continue;
> + }
> + action = irq_desc[i].action;
> + while(action)
> + {
> + if(action->flags & SA_SHIRQ)
> + {
> + if(action->handler(irq, action->dev_id, regs) == IRQ_HANDLED)
> + desc->irqs_unhandled = 0;
> + }
> + action = action->next;
> + }
> + spin_unlock(&irq_desc[i].lock);
> + }
> +}
> +
> +/*
> * If 99,900 of the previous 100,000 interrupts have not been handled then
> * assume that the IRQ is stuck in some manner. Drop a diagnostic and try to
> * turn the IRQ off.
> @@ -289,13 +321,68 @@
> *
> * Called under desc->lock
> */
> -static void note_interrupt(int irq, irq_desc_t *desc, irqreturn_t action_ret)
> +static void note_interrupt(int irq, irq_desc_t *desc, irqreturn_t action_ret, struct pt_regs *regs)
> {
> if (action_ret != IRQ_HANDLED) {
> desc->irqs_unhandled++;
> if (action_ret != IRQ_NONE)
> report_bad_irq(irq, desc, action_ret);
> }
> + if(1)
> + {
> +#ifdef CONFIG_4KSTACKS
> + irqreturn_t action_ret;
> + u32 *isp;
> + union irq_ctx * curctx;
> + union irq_ctx * irqctx;
> +
> + curctx = (union irq_ctx *) current_thread_info();
> + irqctx = hardirq_ctx[smp_processor_id()];
> +
> + spin_unlock(&desc->lock);
> +
> + /*
> + * this is where we switch to the IRQ stack. However, if we are already using
> + * the IRQ stack (because we interrupted a hardirq handler) we can't do that
> + * and just have to keep using the current stack (which is the irq stack already
> + * after all)
> + */
> +
> + if (curctx == irqctx)
> + misrouted_irq(irq, desc, regs);
> + else {
> + /* build the stack frame on the IRQ stack */
> + isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
> + irqctx->tinfo.task = curctx->tinfo.task;
> + irqctx->tinfo.previous_esp = current_stack_pointer();
> +
> + *--isp = (u32) regs;
> + *--isp = (u32) desc;
> + *--isp = (u32) irq;
> +
> + asm volatile(
> + " xchgl %%ebx,%%esp \n"
> + " call misrouted_irq \n"
> + " xchgl %%ebx,%%esp \n"
> + : "=a"(action_ret)
> + : "b"(isp)
> + : "memory", "cc", "edx", "ecx"
> + );
> +
> +
> + }
> + spin_lock(&desc->lock);
> + if (curctx != irqctx)
> + irqctx->tinfo.task = NULL;
> +#else
> + irqreturn_t action_ret;
> + spin_unlock(&desc->lock);
> +
> + misrouted_irq(irq, desc, regs);
> +
> + spin_lock(&desc->lock);
> +#endif
> + }
>
> desc->irq_count++;
> if (desc->irq_count < 100000)
> @@ -487,7 +574,7 @@
> * useful for irq hardware that does not mask cleanly in an
> * SMP environment.
> */
> -#ifdef CONFIG_4KSTACKS
> + #ifdef CONFIG_4KSTACKS
>
> for (;;) {
> irqreturn_t action_ret;
> @@ -532,7 +619,7 @@
> }
> spin_lock(&desc->lock);
> if (!noirqdebug)
> - note_interrupt(irq, desc, action_ret);
> + note_interrupt(irq, desc, action_ret, ®s);
> if (curctx != irqctx)
> irqctx->tinfo.task = NULL;
> if (likely(!(desc->status & IRQ_PENDING)))
> @@ -551,7 +638,7 @@
>
> spin_lock(&desc->lock);
> if (!noirqdebug)
> - note_interrupt(irq, desc, action_ret);
> + note_interrupt(irq, desc, action_ret, ®s);
> if (likely(!(desc->status & IRQ_PENDING)))
> break;
> desc->status &= ~IRQ_PENDING;
> -
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^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2004-09-02 20:43 UTC | newest]
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2004-09-02 20:16 PATCH: prototype "handle broken IRQ routing" patch Alan Cox
2004-09-02 20:38 ` Nathan Bryant
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