[PATCH 2/2] powernv/npu: Prevent overwriting of pnv_npu2_init_contex() callback parameters

[Balbir Singh]

On Fri, Apr 13, 2018 at 12:02 PM, Mark Hairgrove <mhairgrove at nvidia.com> wrote:
>
>
> On Wed, 11 Apr 2018, Alistair Popple wrote:
>
>> There is a single npu context per set of callback parameters. Callers
>> should be prevented from overwriting existing callback values so instead
>> return an error if different parameters are passed.
>>
>> Signed-off-by: Alistair Popple <alistair at popple.id.au>
>> ---
>>  arch/powerpc/include/asm/powernv.h       |  2 +-
>>  arch/powerpc/platforms/powernv/npu-dma.c | 16 +++++++++++++---
>>  2 files changed, 14 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/powernv.h b/arch/powerpc/include/asm/powernv.h
>> index dc5f6a5d4575..362ea12a4501 100644
>> --- a/arch/powerpc/include/asm/powernv.h
>> +++ b/arch/powerpc/include/asm/powernv.h
>> @@ -15,7 +15,7 @@
>>  extern void powernv_set_nmmu_ptcr(unsigned long ptcr);
>>  extern struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
>>                       unsigned long flags,
>> -                     struct npu_context *(*cb)(struct npu_context *, void *),
>> +                     void (*cb)(struct npu_context *, void *),
>>                       void *priv);
>>  extern void pnv_npu2_destroy_context(struct npu_context *context,
>>                               struct pci_dev *gpdev);
>> diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
>> index cb77162f4e7a..193f43ea3fbc 100644
>> --- a/arch/powerpc/platforms/powernv/npu-dma.c
>> +++ b/arch/powerpc/platforms/powernv/npu-dma.c
>> @@ -407,7 +407,7 @@ struct npu_context {
>>       bool nmmu_flush;
>>
>>       /* Callback to stop translation requests on a given GPU */
>> -     struct npu_context *(*release_cb)(struct npu_context *, void *);
>> +     void (*release_cb)(struct npu_context *context, void *priv);
>>
>>       /*
>>        * Private pointer passed to the above callback for usage by
>> @@ -705,7 +705,7 @@ static const struct mmu_notifier_ops nv_nmmu_notifier_ops = {
>>   */
>>  struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
>>                       unsigned long flags,
>> -                     struct npu_context *(*cb)(struct npu_context *, void *),
>> +                     void (*cb)(struct npu_context *, void *),
>>                       void *priv)
>>  {
>>       int rc;
>> @@ -763,8 +763,18 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
>>        */
>>       spin_lock(&npu_context_lock);
>>       npu_context = mm->context.npu_context;
>> -     if (npu_context)
>> +     if (npu_context) {
>> +             if (npu_context->release_cb != cb ||
>> +                     npu_context->priv != priv) {
>> +                     spin_unlock(&npu_context_lock);
>> +                     opal_npu_destroy_context(nphb->opal_id, mm->context.id,
>> +                                             PCI_DEVID(gpdev->bus->number,
>> +                                                     gpdev->devfn));
>> +                     return ERR_PTR(-EINVAL);
>> +             }
>> +
>>               WARN_ON(!kref_get_unless_zero(&npu_context->kref));
>> +     }
>>       spin_unlock(&npu_context_lock);
>>
>>       if (!npu_context) {
>> --
>> 2.11.0
>>
>>
>
> Reviewed-by: Mark Hairgrove <mhairgrove at nvidia.com>
> Tested-by: Mark Hairgrove <mhairgrove at nvidia.com>
>

Reviewed-by: Balbir Singh <bsingharora at gmail.com>