linux/drivers/dma-buf/Kconfig
Christian König bb42df4662 dma-buf: add dynamic DMA-buf handling v15
On the exporter side we add optional explicit pinning callbacks. Which are
called when the importer doesn't implement dynamic handling, move notification
or need the DMA-buf locked in place for its use case.

On the importer side we add an optional move_notify callback. This callback is
used by the exporter to inform the importers that their mappings should be
destroyed as soon as possible.

This allows the exporter to provide the mappings without the need to pin
the backing store.

v2: don't try to invalidate mappings when the callback is NULL,
    lock the reservation obj while using the attachments,
    add helper to set the callback
v3: move flag for invalidation support into the DMA-buf,
    use new attach_info structure to set the callback
v4: use importer_priv field instead of mangling exporter priv.
v5: drop invalidation_supported flag
v6: squash together with pin/unpin changes
v7: pin/unpin takes an attachment now
v8: nuke dma_buf_attachment_(map|unmap)_locked,
    everything is now handled backward compatible
v9: always cache when export/importer don't agree on dynamic handling
v10: minimal style cleanup
v11: drop automatically re-entry avoidance
v12: rename callback to move_notify
v13: add might_lock in appropriate places
v14: rebase on separated locking change
v15: add EXPERIMENTAL flag, some more code comments

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/353993/?series=73646&rev=1
2020-02-27 14:58:00 +01:00

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# 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
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
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.
But marked experimental because we don''t jet have a consistent execution
context and memory management between drivers.
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.
source "drivers/dma-buf/heaps/Kconfig"
endmenu