lkml.org 
[lkml]   [2019]   [Mar]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] mbigen: don't clear eventid when free_irq
From
Date

Hi Marc
On 2019/3/21 17:11, Marc Zyngier wrote:
> On Sat, 16 Mar 2019 11:15:03 +0000
> chenjianguo <chenjianguo3@huawei.com> wrote:
>
>> From: Jianguo Chen <chenjianguo3@huawei.com>
>>
>> mbigen_write_msg clears eventid bits of a mbigen register
>> when free a interrupt, because msi_domain_deactivate memset
>> struct msg to zero. Then multiple mbigen pins with zero eventid
>> will report the same interrupt number.
>>
>> The eventid clear call trace:
>> free_irq
>> __free_irq
>> irq_shutdown
>> irq_domain_deactivate_irq
>> __irq_domain_deactivate_irq
>> __irq_domain_deactivate_irq
>> msi_domain_deactivate
>> platform_msi_write_msg
>> mbigen_write_msg
>>
>> Signed-off-by: Jianguo Chen <chenjianguo3@huawei.com>
>> ---
>> drivers/irqchip/irq-mbigen.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/irqchip/irq-mbigen.c b/drivers/irqchip/irq-mbigen.c
>> index 567b29c..fad7291 100644
>> --- a/drivers/irqchip/irq-mbigen.c
>> +++ b/drivers/irqchip/irq-mbigen.c
>> @@ -161,6 +161,9 @@ static void mbigen_write_msg(struct msi_desc *desc,
>> struct msi_msg *msg)
>> void __iomem *base = d->chip_data;
>> u32 val;
>>
>> + if (!msg->address_lo && !msg->address_hi)
>> + return;
>> +
>> base += get_mbigen_vec_reg(d->hwirq);
>> val = readl_relaxed(base);
>>
>
> For whatever reason, I couldn't apply this patch (even when fishing a
> copy of this email from the archives). It seems to be corrupted is
> various ways, so I had to write the patch from scratch, which is not the
> most reliable way to work. Good thing this was something trivial, I
> wouldn't do it for something more complicated.
>
> In the future, please make sure to use 'git send-email' to send your
> patches, as it is known to work correctly.
>
> Thanks,
>
> M.
>

Mbigen vector register and pin structure shows as below:

event id 0 1 2 127
vector register reg0 reg1 reg2 reg127
| | | |
MBIGEN pin0 pin1 pin2 ... pin127
|-----|-----|-----|-----|
| | | | |
device interrupt num0 num1 num2 num127

Suppose a device driver requested irq num0 and num1 at the beginning,
and for some reason it freed irq num1, mbigen_write_msg will write reg1
with event id 0. Then the pin1 probably mistakenly report interrupt num0
to device driver if there is a signal on the pin.


event id 0 0 2 127
vector register reg0 reg1 reg2 reg127
| | | |
MBIGEN pin0 pin1 pin2 ... pin127
|-----|-----|-----|-----|
| | | | |
device interrup num0 num1 num2 num127

Thanks,
Jianguo Chen

\
 
 \ /
  Last update: 2019-03-21 14:22    [W:0.061 / U:8.544 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site