diff options
| -rw-r--r-- | Documentation/DMA-attributes.txt | 10 | ||||
| -rw-r--r-- | include/linux/dma-mapping.h | 7 |
2 files changed, 17 insertions, 0 deletions
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). diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 10c5a17b1f51..c24721a33b4c 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -63,6 +63,13 @@ #define DMA_ATTR_NO_WARN (1UL << 8) /* + * DMA_ATTR_PRIVILEGED: used to indicate that the buffer is fully + * accessible at an elevated privilege level (and ideally inaccessible or + * at least read-only at lesser-privileged levels). + */ +#define DMA_ATTR_PRIVILEGED (1UL << 9) + +/* * A dma_addr_t can hold any valid DMA or bus address for the platform. * It can be given to a device to use as a DMA source or target. A CPU cannot * reference a dma_addr_t directly because there may be translation between |