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Diffstat (limited to 'kernel/dma/Kconfig')
| -rw-r--r-- | kernel/dma/Kconfig | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig index ca88b867e7fe..61cebea36d89 100644 --- a/kernel/dma/Kconfig +++ b/kernel/dma/Kconfig @@ -53,3 +53,39 @@ config DMA_REMAP config DMA_DIRECT_REMAP bool select DMA_REMAP + +config DMA_API_DEBUG + bool "Enable debugging of DMA-API usage" + select NEED_DMA_MAP_STATE + help + Enable this option to debug the use of the DMA API by device drivers. + With this option you will be able to detect common bugs in device + drivers like double-freeing of DMA mappings or freeing mappings that + were never allocated. + + This also attempts to catch cases where a page owned by DMA is + accessed by the cpu in a way that could cause data corruption. For + example, this enables cow_user_page() to check that the source page is + not undergoing DMA. + + This option causes a performance degradation. Use only if you want to + debug device drivers and dma interactions. + + If unsure, say N. + +config DMA_API_DEBUG_SG + bool "Debug DMA scatter-gather usage" + default y + depends on DMA_API_DEBUG + help + Perform extra checking that callers of dma_map_sg() have respected the + appropriate segment length/boundary limits for the given device when + preparing DMA scatterlists. + + This is particularly likely to have been overlooked in cases where the + dma_map_sg() API is used for general bulk mapping of pages rather than + preparing literal scatter-gather descriptors, where there is a risk of + unexpected behaviour from DMA API implementations if the scatterlist + is technically out-of-spec. + + If unsure, say N. |