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Message-ID: <494985E1.90304@goop.org>
Date: Wed, 17 Dec 2008 15:06:09 -0800
From: Jeremy Fitzhardinge <jeremy@...p.org>
To: Ingo Molnar <mingo@...e.hu>
CC: the arch/x86 maintainers <x86@...nel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: add handle_irq() to allow interrupt injection
Ingo Molnar wrote:
> * Jeremy Fitzhardinge <jeremy@...p.org> wrote:
>
>
>> Xen uses a different interrupt path, so introduce handle_irq() to
>> allow interrupts to be inserted into the normal interrupt path. This
>> is handled slightly differently on 32 and 64-bit.
>>
>> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
>> ---
>> arch/x86/include/asm/irq.h | 1 +
>> arch/x86/kernel/irq_32.c | 34 +++++++++++++++++++++-------------
>> arch/x86/kernel/irq_64.c | 23 ++++++++++++++++-------
>> 3 files changed, 38 insertions(+), 20 deletions(-)
>>
>> ===================================================================
>> --- a/arch/x86/include/asm/irq.h
>> +++ b/arch/x86/include/asm/irq.h
>> @@ -39,6 +39,7 @@
>> extern unsigned int do_IRQ(struct pt_regs *regs);
>> extern void init_IRQ(void);
>> extern void native_init_IRQ(void);
>> +extern bool handle_irq(unsigned irq, struct pt_regs *regs);
>>
>> /* Interrupt vector management */
>> extern DECLARE_BITMAP(used_vectors, NR_VECTORS);
>> ===================================================================
>> --- a/arch/x86/kernel/irq_32.c
>> +++ b/arch/x86/kernel/irq_32.c
>> @@ -191,6 +191,26 @@
>> execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) { return 0; }
>> #endif
>>
>> +bool handle_irq(unsigned irq, struct pt_regs *regs)
>> +{
>> + struct irq_desc *desc;
>> + int overflow;
>> +
>> + overflow = check_stack_overflow();
>> +
>> + desc = irq_to_desc(irq);
>> + if (unlikely(!desc))
>> + return false;
>> +
>> + if (!execute_on_irq_stack(overflow, desc, irq)) {
>> + if (unlikely(overflow))
>> + print_stack_overflow();
>> + desc->handle_irq(irq, desc);
>> + }
>> +
>> + return true;
>> +}
>> +
>> /*
>> * do_IRQ handles all normal device IRQ's (the special
>> * SMP cross-CPU interrupts have their own specific
>> @@ -200,31 +220,19 @@
>> {
>> struct pt_regs *old_regs;
>> /* high bit used in ret_from_ code */
>> - int overflow;
>> unsigned vector = ~regs->orig_ax;
>> - struct irq_desc *desc;
>> unsigned irq;
>>
>> -
>> old_regs = set_irq_regs(regs);
>> irq_enter();
>> irq = __get_cpu_var(vector_irq)[vector];
>>
>> - overflow = check_stack_overflow();
>> -
>> - desc = irq_to_desc(irq);
>> - if (unlikely(!desc)) {
>> + if (!handle_irq(irq, regs)) {
>> printk(KERN_EMERG "%s: cannot handle IRQ %d vector %#x cpu %d\n",
>> __func__, irq, vector, smp_processor_id());
>> BUG();
>> }
>>
>> - if (!execute_on_irq_stack(overflow, desc, irq)) {
>> - if (unlikely(overflow))
>> - print_stack_overflow();
>> - desc->handle_irq(irq, desc);
>> - }
>> -
>> irq_exit();
>> set_irq_regs(old_regs);
>> return 1;
>> ===================================================================
>> --- a/arch/x86/kernel/irq_64.c
>> +++ b/arch/x86/kernel/irq_64.c
>> @@ -40,6 +40,20 @@
>> #endif
>> }
>>
>> +bool handle_irq(unsigned irq, struct pt_regs *regs)
>> +{
>> + struct irq_desc *desc;
>> +
>> + stack_overflow_check(regs);
>> +
>> + desc = irq_to_desc(irq);
>> + if (unlikely(!desc))
>> + return false;
>> +
>> + generic_handle_irq_desc(irq, desc);
>> + return true;
>> +}
>> +
>> /*
>> * do_IRQ handles all normal device IRQ's (the special
>> * SMP cross-CPU interrupts have their own specific
>> @@ -48,7 +62,6 @@
>> asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
>> {
>> struct pt_regs *old_regs = set_irq_regs(regs);
>> - struct irq_desc *desc;
>>
>> /* high bit used in ret_from_ code */
>> unsigned vector = ~regs->orig_ax;
>> @@ -56,14 +69,10 @@
>>
>> exit_idle();
>> irq_enter();
>> +
>> irq = __get_cpu_var(vector_irq)[vector];
>>
>> - stack_overflow_check(regs);
>> -
>> - desc = irq_to_desc(irq);
>> - if (likely(desc))
>> - generic_handle_irq_desc(irq, desc);
>> - else {
>> + if (!handle_irq(irq, regs)) {
>> if (!disable_apic)
>> ack_APIC_irq();
>>
>>
>
> the changes look rather similar. Could you please look into unifying
> irq_*.c before adding more logic to it?
>
I didn't really add more logic - I just hoisted some existing code into
a new function.
It does make do_IRQ() itself trivial to unify now. But the rest looks
non-trivial: fixup_irqs() is quite different, as is the interrupt stack
stuff.
Hm, what does asmlinkage do on x86-64?
J
Subject: x86: unify do_IRQ()
With the differences in interrupt handling hoisted into handle_irq(),
do_IRQ is more or less identical between 32 and 64 bit, so unify it.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
---
arch/x86/include/asm/irq.h | 1 -
arch/x86/kernel/irq.c | 41 +++++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/irq_32.c | 27 ---------------------------
arch/x86/kernel/irq_64.c | 33 ---------------------------------
4 files changed, 41 insertions(+), 61 deletions(-)
===================================================================
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -36,7 +36,6 @@
extern void fixup_irqs(cpumask_t map);
#endif
-extern unsigned int do_IRQ(struct pt_regs *regs);
extern void init_IRQ(void);
extern void native_init_IRQ(void);
extern bool handle_irq(unsigned irq, struct pt_regs *regs);
===================================================================
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -5,10 +5,12 @@
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/seq_file.h>
+#include <linux/ftrace.h>
#include <asm/apic.h>
#include <asm/io_apic.h>
#include <asm/smp.h>
+#include <asm/idle.h>
atomic_t irq_err_count;
@@ -195,3 +197,42 @@
#endif
return sum;
}
+
+
+/*
+ * do_IRQ handles all normal device IRQ's (the special
+ * SMP cross-CPU interrupts have their own specific
+ * handlers).
+ */
+#ifdef CONFIG_X86_64
+asmlinkage
+#endif
+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;
+
+ exit_idle();
+ irq_enter();
+
+ irq = __get_cpu_var(vector_irq)[vector];
+
+ if (!handle_irq(irq, regs)) {
+#ifdef CONFIG_X86_64
+ if (!disable_apic)
+ ack_APIC_irq();
+#endif
+
+ if (printk_ratelimit())
+ printk(KERN_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;
+}
===================================================================
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -211,33 +211,6 @@
return true;
}
-/*
- * do_IRQ handles all normal device IRQ's (the special
- * SMP cross-CPU interrupts have their own specific
- * handlers).
- */
-unsigned int do_IRQ(struct pt_regs *regs)
-{
- struct pt_regs *old_regs;
- /* high bit used in ret_from_ code */
- unsigned vector = ~regs->orig_ax;
- unsigned irq;
-
- old_regs = set_irq_regs(regs);
- irq_enter();
- irq = __get_cpu_var(vector_irq)[vector];
-
- if (!handle_irq(irq, regs)) {
- printk(KERN_EMERG "%s: cannot handle IRQ %d vector %#x cpu %d\n",
- __func__, irq, vector, smp_processor_id());
- BUG();
- }
-
- irq_exit();
- set_irq_regs(old_regs);
- return 1;
-}
-
#ifdef CONFIG_HOTPLUG_CPU
#include <mach_apic.h>
===================================================================
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -55,39 +55,6 @@
return true;
}
-/*
- * do_IRQ handles all normal device IRQ's (the special
- * SMP cross-CPU interrupts have their own specific
- * handlers).
- */
-asmlinkage 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;
-
- exit_idle();
- irq_enter();
-
- irq = __get_cpu_var(vector_irq)[vector];
-
- if (!handle_irq(irq, regs)) {
- if (!disable_apic)
- ack_APIC_irq();
-
- if (printk_ratelimit())
- printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n",
- __func__, smp_processor_id(), vector);
- }
-
- irq_exit();
-
- set_irq_regs(old_regs);
- return 1;
-}
-
#ifdef CONFIG_HOTPLUG_CPU
void fixup_irqs(cpumask_t map)
{
--
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