[PATCH v3 2/2] OMAP: IOMMU: add support to callback during fault handling

[Ramirez Luna, Omar]

Hi,

On Mon, Feb 21, 2011 at 3:12 PM, David Cohen <dacohen at gmail.com> wrote:
> Generic errors codes make easier to threat possible IOMMU users which
> have (partially or totally) common drivers for different OMAP
> versions.

Agree then.

>>> +       /* Fault callback or TLB/PTE Dynamic loading */
>>> +       if (obj->isr && !obj->isr(obj, da, errs, obj->isr_priv))
>>>                return IRQ_HANDLED;
>>
>> BTW, why not changing the name isr for cb, it is confusing since there
>> is another fault_isr called by mmu, AFAIK nobody uses obj->isr
>
> The main purpose of this function is to be an ISR, not only callback.

Yep, I just thought it was a bit too much of:
(1) The real isr: iommu_fault_handler, set on request_irq
(2) A plugged fault_isr for mach specific code: omap2_iommu_fault_isr,
for error reporting.
(3) And then a plugged custom isr, to be set by the user.

Feel free to ignore.

>> So I think the following will be bad practice:
>>
>>        mmu = iommu_get("iva2");
>>        if (!IS_ERR(mmu))
>>                mmu->isr = mmu_fault_callback;
>>
>> Shall we think anything to prevent such mis-usage?
>
> Well, the IOMMU user has access to IOMMU obj, so it can not only
> change the (*isr)() but to mess with a lot of other stuff. The only
> way to prevent it is to avoid user to have obj. But then, this fix (or
> issue) does not belong to this patch.

Agree, just pointing out.

Regards,

Omar