Comparing a GCD attribute field directly against EFI_MEMORY_UC and EFI_MEMORY_WT is incorrect, since it may have other bits set as well which are not related to the cacheability of the region. So instead, test explicitly against the flags EFI_MEMORY_WB and EFI_MEMORY_WT, which must be set if the region may be mapped with cacheable attributes.
Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel <[email protected]> --- ArmPkg/Library/ArmDmaLib/ArmDmaLib.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c b/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c index 834afdba10ef..7f6598318a91 100644 --- a/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c +++ b/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c @@ -101,9 +101,7 @@ DmaMap ( } // If the mapped buffer is not an uncached buffer - if ( (GcdDescriptor.Attributes != EFI_MEMORY_WC) && - (GcdDescriptor.Attributes != EFI_MEMORY_UC) ) - { + if ((GcdDescriptor.Attributes & (EFI_MEMORY_WB | EFI_MEMORY_WT)) != 0) { // // If the buffer does not fill entire cache lines we must double buffer into // uncached memory. Device (PCI) address becomes uncached page. -- 2.5.0 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
