Re: [edk2-devel] [edk2-platforms][PATCH V1] Silicon/Synopsys/DesignWare: DwEmacSnpDxe: Fix bug in EmacGetDmaStatus

["Pedro Falcato" <pedro.falcato@gmail.com>]

On Fri, Jul 28, 2023 at 5:00 AM wangy <wangyzhaoz@163.com> wrote:
>
> From: Yang Wang <wangyzhaoz@163.com>
>
> If IrqStat is NULL, the interrupt status will not be
> read from the device.When the interrupt status is read,
> it will also be cleared.

Let's improve the commit message a bit, something like:

The EFI spec (see UEFI 2.10, 24.1.12) requires
EFI_SIMPLE_NETWORK.GetStatus() to handle NULL InterruptStatus pointers
by not reading nor clearing the interrupt status from the device.

However, EmacGetDmaStatus (part of the DwEmacSnpDxe GetStatus()
implementation) did not correctly handle NULL IrqStat, despite already
being tagged as an OPTIONAL argument. This made calling GetStatus()
with a NULL pointer (for example, the call in MnpRecycleTxBuf) either
corrupt memory or straight-up crash.

Make it EFI spec compliant, by adding proper NULL pointer checks
around RI_SET_MSK and TI_SET_MSK retrieval/clearing.

--

In any case, take my:

Acked-by: Pedro Falcato <pedro.falcato@gmail.com>

> Cc: Leif Lindholm <quic_llindhol@quicinc.com>
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: Ran Wang <wangran@bosc.ac.cn>
>
> Signed-off-by: Yang Wang <wangyzhaoz@163.com>
> ---
>  .../Drivers/DwEmacSnpDxe/EmacDxeUtil.c        | 22 ++++++++++++-------
>  1 file changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/Silicon/Synopsys/DesignWare/Drivers/DwEmacSnpDxe/EmacDxeUtil.c b/Silicon/Synopsys/DesignWare/Drivers/DwEmacSnpDxe/EmacDxeUtil.c
> index 3b982ce984..26d3ff6138 100755
> --- a/Silicon/Synopsys/DesignWare/Drivers/DwEmacSnpDxe/EmacDxeUtil.c
> +++ b/Silicon/Synopsys/DesignWare/Drivers/DwEmacSnpDxe/EmacDxeUtil.c
> @@ -500,24 +500,30 @@ EmacGetDmaStatus (
>    UINT32  ErrorBit;
>    UINT32  Mask = 0;
>
> +  if (IrqStat != NULL) {
> +    *IrqStat = 0;
> +  }
> +
>    DmaStatus = MmioRead32 (MacBaseAddress +
>                             DW_EMAC_DMAGRP_STATUS_OFST);
>    if (DmaStatus & DW_EMAC_DMAGRP_STATUS_NIS_SET_MSK) {
>      Mask |= DW_EMAC_DMAGRP_STATUS_NIS_SET_MSK;
>      // Rx interrupt
>      if (DmaStatus & DW_EMAC_DMAGRP_STATUS_RI_SET_MSK) {
> -      *IrqStat |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
> -      Mask |= DW_EMAC_DMAGRP_STATUS_RI_SET_MSK;
> -    } else {
> -      *IrqStat &= ~EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
> +      if (IrqStat != NULL) {
> +        *IrqStat |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
> +        Mask |= DW_EMAC_DMAGRP_STATUS_RI_SET_MSK;
> +      }
>      }
> +
>      // Tx interrupt
>      if (DmaStatus & DW_EMAC_DMAGRP_STATUS_TI_SET_MSK) {
> -      *IrqStat |= EFI_SIMPLE_NETWORK_TRANSMIT_INTERRUPT;
> -      Mask |= DW_EMAC_DMAGRP_STATUS_TI_SET_MSK;
> -    } else {
> -      *IrqStat &= ~EFI_SIMPLE_NETWORK_TRANSMIT_INTERRUPT;
> +      if (IrqStat != NULL) {
> +        *IrqStat |= EFI_SIMPLE_NETWORK_TRANSMIT_INTERRUPT;
> +        Mask |= DW_EMAC_DMAGRP_STATUS_TI_SET_MSK;
> +      }
>      }
> +
>      // Tx Buffer
>      if (DmaStatus & DW_EMAC_DMAGRP_STATUS_TU_SET_MSK){
>        Mask |= DW_EMAC_DMAGRP_STATUS_TU_SET_MSK;
> --
> 2.25.1
>
>
>
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>


-- 
Pedro


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