Hi, all

I`m yangcheng, and I found this bug when using the edk2-platforms/Silicon/Synopsys/DesignWare/Drivers/DwEmmcDxe driver on my VisionFive2 development board, which does not support the CMO instruction set.  There are many functions in DwEmmcDxe.c that call Cache operations. For example, the DwEmmcReadBlockData function below calls WriteBackDataCacheRange().

 

EFI_STATUS

DwEmmcReadBlockData (

  IN EFI_MMC_HOST_PROTOCOL     *This,

  IN EFI_LBA                    Lba,

  IN UINTN                      Length,

  IN UINT32*                   Buffer

  )

{

 

  .......

 

  WriteBackDataCacheRange (gpIdmacDesc, DescPages * EFI_PAGE_SIZE);

  StartDma (Length);

 

  Status = SendCommand (mDwEmmcCommand, mDwEmmcArgument);

  if (EFI_ERROR (Status)) {

    DEBUG ((DEBUG_ERROR, "Failed to read data, mDwEmmcCommand:%x, mDwEmmcArgument:%x, Status:%r\n", mDwEmmcCommand, mDwEmmcArgument, Status));

    goto out;

  }

out:

  // Restore Tpl

  gBS->RestoreTPL (Tpl);

  return Status;

}

 

Initially, I didn't set PcdRiscVFeatureOverride, so I got an illegal instruction exception. Then I set my PcdRiscVFeatureOverride to 0xFFFFFFFFFFFFFFFE to avoid using the CMO instruction set, and I got an ASSERT. 

Most cross-platform driver codes may call Cache management operations. Modifying these driver codes may cost a lot, and I think we may need some better way than ASSERT.

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