[PATCH] ARM64: gic: Do not allow bypass FIQ signals to reach to processor

[panand@redhat.com (Pratyush Anand)]

On Friday 13 February 2015 01:43 PM, Pratyush Anand wrote:
> Hi Jason,
>
> On Monday 09 February 2015 11:48 AM, Pratyush Anand wrote:
>> In some case few signals of an IP(like PMU Overflow in APM88xx0x) can be
>> mapped to nLEGACYFIQ, ie nFIQ of CPU. Until ARM64 supports FIQ handling,
>> we will get nice "Bad mode in FIQ handler detected"
>>
>> Therefore force FIQBypDisGrp1 to '1', so that bypass FIQ signal is not
>> signaled to the processor.
>>
>
> Please review this patch.

ping

>
> ~Pratyush
>
>> Signed-off-by: Pratyush Anand <panand@redhat.com>
>> ---
>>   drivers/irqchip/irq-gic.c       | 9 ++++++++-
>>   include/linux/irqchip/arm-gic.h | 1 +
>>   2 files changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
>> index d617ee5a3d8a..525dfc966e60 100644
>> --- a/drivers/irqchip/irq-gic.c
>> +++ b/drivers/irqchip/irq-gic.c
>> @@ -362,7 +362,14 @@ static void gic_cpu_if_up(void)
>>       */
>>       bypass = readl(cpu_base + GIC_CPU_CTRL);
>>       bypass &= GICC_DIS_BYPASS_MASK;
>> -
>> +#ifdef CONFIG_ARM64
>> +    /* FIXME: when ARM64 starts supporting FIQ mode.
>> +     *
>> +     * Until ARM64 supports FIQ handling, force FIQBypDisGrp1 to
>> +     * '1', so that bypass FIQ signal is not signaled to the processor.
>> +     */
>> +    bypass |= GICC_DIS_BYPASS_FIQ_TO_CPU;
>> +#endif
>>       writel_relaxed(bypass | GICC_ENABLE, cpu_base + GIC_CPU_CTRL);
>>   }
>>
>> diff --git a/include/linux/irqchip/arm-gic.h
>> b/include/linux/irqchip/arm-gic.h
>> index 71d706d5f169..c9fdd1972625 100644
>> --- a/include/linux/irqchip/arm-gic.h
>> +++ b/include/linux/irqchip/arm-gic.h
>> @@ -25,6 +25,7 @@
>>   #define GICC_INT_PRI_THRESHOLD        0xf0
>>   #define GICC_IAR_INT_ID_MASK        0x3ff
>>   #define GICC_INT_SPURIOUS        1023
>> +#define GICC_DIS_BYPASS_FIQ_TO_CPU    (1 << 5)
>>   #define GICC_DIS_BYPASS_MASK        0x1e0
>>
>>   #define GIC_DIST_CTRL            0x000
>>