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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