linux-kernel - Re: [patch] x86: handle legacy PIC interrupts on all the cpu's

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Date:	Mon, 15 Mar 2010 23:35:49 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Suresh Siddha <suresh.b.siddha@...el.com>
CC:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [patch] x86: handle legacy PIC interrupts on all the cpu's

On 03/15/2010 11:54 PM, Suresh Siddha wrote:
> On Mon, 2010-03-15 at 22:37 -0700, Ingo Molnar wrote:
>> * Yinghai Lu <yinghai@...nel.org> wrote:
>>
>>> On 03/15/2010 03:56 PM, Suresh Siddha wrote:
>>>> On Mon, 2010-03-15 at 14:51 -0700, Yinghai Lu wrote:
>>>>>> +	for (irq = 0; irq < legacy_pic->nr_legacy_irqs; irq++)
>>>>>> +		if (!IO_APIC_IRQ(irq))
>>>>>> +			per_cpu(vector_irq, cpu)[IRQ0_VECTOR + irq] = irq;
>>>>>
>>>>> seems those three lines are not needed...
>>>>
>>>> Those are needed for !CONFIG_X86_IO_APIC case.
>>>>
>>> then we can have
>>>
>>> +#ifndef CONFIG_X86_IO_APIC
>>> +	for (irq = 0; irq < legacy_pic->nr_legacy_irqs; irq++)
>>> +		per_cpu(vector_irq, cpu)[IRQ0_VECTOR + irq] = irq;
>>> +#endif
>>>
>>> then we don't punish most setup with ioapic controller.
>>
>> Ok - i've simplified the code with the above and have added your Acked-by - is 
>> that is fine by you?
> 
> Ingo, Probably appended one is a better version. Yinghai can you please
> Ack if it is ok. Thanks.
> 
> ---
> From: Suresh Siddha <suresh.b.siddha@...el.com>
> Subject: x86: handle legacy PIC interrupts on all the cpu's
> 
> Ingo Molnar reported that with the recent changes of not statically blocking
> IRQ0_VECTOR..IRQ15_VECTOR's on all the cpu's, broke an AMD platform
> (with Nvidia chipset) boot when "noapic" boot option is used.
> 
> On this platform, legacy PIC interrupts are getting delivered to all the
> cpu's instead of just the boot cpu. Thus not initializing the vector to irq
> mapping for the legacy irq's resulted in not handling certain interrupts
> causing boot hang.
> 
> Fix this by initializing the vector to irq mapping on all the logical cpu's,
> if the legacy IRQ is handled by the legacy PIC.
> 
> Reported-by: Ingo Molnar <mingo@...e.hu>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com>
> ---
> 
>  arch/x86/include/asm/hw_irq.h  |    3 +--
>  arch/x86/kernel/apic/io_apic.c |    9 +++++++++
>  arch/x86/kernel/irqinit.c      |   20 ++++++++++++++++++++
>  3 files changed, 30 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
> index a929c9e..564a7a1 100644
> --- a/arch/x86/include/asm/hw_irq.h
> +++ b/arch/x86/include/asm/hw_irq.h
> @@ -133,15 +133,14 @@ extern void (*__initconst interrupt[NR_VECTORS-FIRST_EXTERNAL_VECTOR])(void);
>  
>  typedef int vector_irq_t[NR_VECTORS];
>  DECLARE_PER_CPU(vector_irq_t, vector_irq);
> +extern void __setup_vector_irq(int cpu);
>  
>  #ifdef CONFIG_X86_IO_APIC
>  extern void lock_vector_lock(void);
>  extern void unlock_vector_lock(void);
> -extern void __setup_vector_irq(int cpu);
>  #else
>  static inline void lock_vector_lock(void) {}
>  static inline void unlock_vector_lock(void) {}
> -static inline void __setup_vector_irq(int cpu) {}
>  #endif
>  
>  #endif /* !ASSEMBLY_ */
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index e4e0ddc..fd3cecd 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -1268,6 +1268,15 @@ void __setup_vector_irq(int cpu)
>  	/* Mark the inuse vectors */
>  	for_each_irq_desc(irq, desc) {
>  		cfg = desc->chip_data;
> +
> +		/*
> +		 * If it is a legacy IRQ handled by the legacy PIC, be ready
> +		 * to handle it on any CPU, as the PIC interrupts are delivered
> +		 * to multiple cpu's on some platforms.
> +		 */
> +		if (irq < legacy_pic->nr_legacy_irqs && !IO_APIC_IRQ(irq))
> +			cpumask_set_cpu(cpu, cfg->domain);
> +
>  		if (!cpumask_test_cpu(cpu, cfg->domain))
>  			continue;
>  		vector = cfg->vector;
> diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
> index ef257fc..afc3b31 100644
> --- a/arch/x86/kernel/irqinit.c
> +++ b/arch/x86/kernel/irqinit.c
> @@ -141,6 +141,26 @@ void __init init_IRQ(void)
>  	x86_init.irqs.intr_init();
>  }
>  
> +#ifndef CONFIG_X86_IO_APIC
> +/*
> + * Setup the vector to irq mappings.
> + */
> +void __setup_vector_irq(int cpu)
> +{
> +	int irq;
> +
> +	/*
> +	 * On most of the platforms, legacy PIC delivers the interrupts on the
> +	 * boot cpu. But there are certain platforms where PIC interrupts are
> +	 * delivered to multiple cpu's. For the new cpu that is coming online,
> +	 * setup the static legacy vector to irq mapping.
> +	 */
> +	for (irq = 0; irq < legacy_pic->nr_legacy_irqs; irq++)
> +		per_cpu(vector_irq, cpu)[IRQ0_VECTOR + irq] = irq;
> +
> +}
> +#endif
> +
>  static void __init smp_intr_init(void)
>  {
>  #ifdef CONFIG_SMP
> 

yes, less one one function prototype.

Acked-by: Yinghai Lu <yinghai@...nel.org>

Yinghai

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