# SPDX-License-Identifier: GPL-2.0-only
menu "DMABUF options"
config SYNC_FILE
bool "Explicit Synchronization Framework"
default n
select DMA_SHARED_BUFFER
help
The Sync File Framework adds explicit synchronization via
userspace. It enables send/receive 'struct dma_fence' objects to/from
userspace via Sync File fds for synchronization between drivers via
userspace components. It has been ported from Android.
The first and main user for this is graphics in which a fence is
associated with a buffer. When a job is submitted to the GPU a fence
is attached to the buffer and is transferred via userspace, using Sync
Files fds, to the DRM driver for example. More details at
Documentation/driver-api/sync_file.rst.
config SW_SYNC
bool "Sync File Validation Framework"
default n
depends on SYNC_FILE
depends on DEBUG_FS
help
A sync object driver that uses a 32bit counter to coordinate
synchronization. Useful when there is no hardware primitive backing
the synchronization.
WARNING: improper use of this can result in deadlocking kernel
drivers from userspace. Intended for test and debug only.
config UDMABUF
bool "userspace dmabuf misc driver"
default n
depends on DMA_SHARED_BUFFER
depends on MEMFD_CREATE || COMPILE_TEST
depends on MMU
help
A driver to let userspace turn memfd regions into dma-bufs.
Qemu can use this to create host dmabufs for guest framebuffers.
config DMABUF_MOVE_NOTIFY
bool "Move notify between drivers (EXPERIMENTAL)"
default n
depends on DMA_SHARED_BUFFER
help
Don't pin buffers if the dynamic DMA-buf interface is available on
both the exporter as well as the importer. This fixes a security
problem where userspace is able to pin unrestricted amounts of memory
through DMA-buf.
This is marked experimental because we don't yet have a consistent
execution context and memory management between drivers.
config DMABUF_DEBUG
bool "DMA-BUF debug checks"
depends on DMA_SHARED_BUFFER
default y if DMA_API_DEBUG
help
This option enables additional checks for DMA-BUF importers and
exporters. Specifically it validates that importers do not peek at the
underlying struct page when they import a buffer.
config DMABUF_SELFTESTS
tristate "Selftests for the dma-buf interfaces"
default n
depends on DMA_SHARED_BUFFER
menuconfig DMABUF_HEAPS
bool "DMA-BUF Userland Memory Heaps"
select DMA_SHARED_BUFFER
help
Choose this option to enable the DMA-BUF userland memory heaps.
This options creates per heap chardevs in /dev/dma_heap/ which
allows userspace to allocate dma-bufs that can be shared
between drivers.
menuconfig DMABUF_SYSFS_STATS
bool "DMA-BUF sysfs statistics (DEPRECATED)"
depends on DMA_SHARED_BUFFER
help
Choose this option to enable DMA-BUF sysfs statistics
in location /sys/kernel/dmabuf/buffers.
/sys/kernel/dmabuf/buffers/<inode_number> will contain
statistics for the DMA-BUF with the unique inode number
<inode_number>.
This option is deprecated and should sooner or later be removed.
Android is the only user of this and it turned out that this resulted
in quite some performance problems.
source "drivers/dma-buf/heaps/Kconfig"
endmenu
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