From b2fb366425ceb85dca56afa538257ec5a2c4f6d1 Mon Sep 17 00:00:00 2001 From: Mitchel Humpherys Date: Fri, 6 Jan 2017 18:58:11 +0530 Subject: common: DMA-mapping: add DMA_ATTR_PRIVILEGED attribute This patch adds the DMA_ATTR_PRIVILEGED attribute to the DMA-mapping subsystem. Some advanced peripherals such as remote processors and GPUs perform accesses to DMA buffers in both privileged "supervisor" and unprivileged "user" modes. This attribute is used to indicate to the DMA-mapping subsystem that the buffer is fully accessible at the elevated privilege level (and ideally inaccessible or at least read-only at the lesser-privileged levels). Cc: linux-doc@vger.kernel.org Reviewed-by: Robin Murphy Tested-by: Robin Murphy Acked-by: Will Deacon Signed-off-by: Mitchel Humpherys Signed-off-by: Will Deacon --- Documentation/DMA-attributes.txt | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'Documentation/DMA-attributes.txt') diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index 98bf7ac29aad..44c6bc496eee 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -143,3 +143,13 @@ So, this provides a way for drivers to avoid those error messages on calls where allocation failures are not a problem, and shouldn't bother the logs. NOTE: At the moment DMA_ATTR_NO_WARN is only implemented on PowerPC. + +DMA_ATTR_PRIVILEGED +------------------------------ + +Some advanced peripherals such as remote processors and GPUs perform +accesses to DMA buffers in both privileged "supervisor" and unprivileged +"user" modes. This attribute is used to indicate to the DMA-mapping +subsystem that the buffer is fully accessible at the elevated privilege +level (and ideally inaccessible or at least read-only at the +lesser-privileged levels). -- cgit v1.2.3