On 12/02/2020 20:22, Rob Herring wrote:
> From: Tomeu Vizoso <tomeu.viz...@collabora.com>
> 
> If the exception type isn't a translation fault, don't try to map and
> instead go straight to a terminal fault.
> 
> Otherwise, we can get flooded by kernel warnings and further faults.
> 
> Signed-off-by: Tomeu Vizoso <tomeu.viz...@collabora.com>
> Signed-off-by: Rob Herring <r...@kernel.org>
> ---
> I rewrote this some simplifying the code and somewhat following Steven's 
> suggested. Still not using defines though. No defines here was good 
> enough before IMO.

Heresy! It's a good thing you're not writing kbase code - there you
(seemingly) need to pick a #define which is as long as possible, but
then still wrap the code to avoid the 80 character limit... For
example[1]. Although shifting the code right might get you extra bonus
points, deep nesting seems to be encouraged! ;)

[1]
https://gitlab.freedesktop.org/panfrost/mali_kbase/blob/master/driver/product/kernel/drivers/gpu/arm/midgard/backend/gpu/mali_kbase_js_backend.c#L156

> 
> Only compile tested.

I've done some quick testing on a Firefly RK3288. But I don't have any
(handy) tests to trigger non-TRANSLATION_FAULT MMU faults.

Reviewed-by: Steven Price <steven.pr...@arm.com>

Thanks,

Steve

> 
>  drivers/gpu/drm/panfrost/panfrost_mmu.c | 44 +++++++++++--------------
>  1 file changed, 19 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c 
> b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> index 763cfca886a7..4f2836bd9215 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> @@ -596,33 +596,27 @@ static irqreturn_t panfrost_mmu_irq_handler_thread(int 
> irq, void *data)
>               source_id = (fault_status >> 16);
>  
>               /* Page fault only */
> -             if ((status & mask) == BIT(i)) {
> -                     WARN_ON(exception_type < 0xC1 || exception_type > 0xC4);
> -
> +             ret = -1;
> +             if ((status & mask) == BIT(i) && (exception_type & 0xF8) == 
> 0xC0)
>                       ret = panfrost_mmu_map_fault_addr(pfdev, i, addr);
> -                     if (!ret) {
> -                             mmu_write(pfdev, MMU_INT_CLEAR, BIT(i));
> -                             status &= ~mask;
> -                             continue;
> -                     }
> -             }
>  
> -             /* terminal fault, print info about the fault */
> -             dev_err(pfdev->dev,
> -                     "Unhandled Page fault in AS%d at VA 0x%016llX\n"
> -                     "Reason: %s\n"
> -                     "raw fault status: 0x%X\n"
> -                     "decoded fault status: %s\n"
> -                     "exception type 0x%X: %s\n"
> -                     "access type 0x%X: %s\n"
> -                     "source id 0x%X\n",
> -                     i, addr,
> -                     "TODO",
> -                     fault_status,
> -                     (fault_status & (1 << 10) ? "DECODER FAULT" : "SLAVE 
> FAULT"),
> -                     exception_type, panfrost_exception_name(pfdev, 
> exception_type),
> -                     access_type, access_type_name(pfdev, fault_status),
> -                     source_id);
> +             if (ret)
> +                     /* terminal fault, print info about the fault */
> +                     dev_err(pfdev->dev,
> +                             "Unhandled Page fault in AS%d at VA 0x%016llX\n"
> +                             "Reason: %s\n"
> +                             "raw fault status: 0x%X\n"
> +                             "decoded fault status: %s\n"
> +                             "exception type 0x%X: %s\n"
> +                             "access type 0x%X: %s\n"
> +                             "source id 0x%X\n",
> +                             i, addr,
> +                             "TODO",
> +                             fault_status,
> +                             (fault_status & (1 << 10) ? "DECODER FAULT" : 
> "SLAVE FAULT"),
> +                             exception_type, panfrost_exception_name(pfdev, 
> exception_type),
> +                             access_type, access_type_name(pfdev, 
> fault_status),
> +                             source_id);
>  
>               mmu_write(pfdev, MMU_INT_CLEAR, mask);
>  
> 

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