Pull drm updates from Dave Airlie:
"Highlights:
- core: a lot of atomic refactoring in progress, panic got split into
a core/helpers model
- amdgpu: enables HDMI 2.1 FRL and other good things finally, UAlink
over Ethernet support
- xe: has a bunch of CRI support, ras error for bad vram, memory
offlining support.
- msm: enables a bunch more GPUs.
Otherwise it's a the usual mountain of stuff all over the place.
Details:
rust:
- I/O tree shared with driver-core
- DMA tree shared with driver-core
- allow aux registration data closures to return covariant sub-fields
- Implement Send and Sync for MapleTree
- add pci resource flags and IORESOURCE_MEM_64
drm/rust:
- add dma_fence abstraction
- init DRM registrations and their data in place
- drop unused flags argument to registration
vgaarb:
- rework API to pass a private ptr instead of pci device
sound:
- adapt to omapdrm changes
gem:
- add callback for handle count going to 0
gpusvm:
- share one HMM fault and keep single mappings inline
pagemap:
- Prevent CPU stalls during unbounded pagemap teardown
dma-fence:
- fix docs
vga_switcheroo:
- disconnect from fbcon
- update fbcon from within fbdev emulation
atomic:
- move DRM from state reset callbacks to atomic_create_state
- remove drm_simple_encoder_init
panic:
- split into core and helpers
buddy:
- improve dirty tracking
clients:
- improve vmap handling
- fbdev: Move helpers from drm_kms_helper.ko to drm_client_lib.ko
display:
- export HDMI SCDC status data via debugfs
- rework SCDC for better HDMI 2.0 support
- dp/mst: improve DPCD compliance
edid:
- parse AMD VSDB
- parse ALLM/VRR capabilities
- support detecting panel size
log:
- add drm_warn_ratelimited
sched:
- cleanup interface
- add missing locking
- fix run-queue cleanup
- fix locking
sysfb:
- remove obsolete quirk for Lenovo D330
- fix panel orientation for non-native display modes
- drop drm_class_device_register
colorop:
- provide DRM_COLOR_OP_FIXED_MATRIX
bridge:
- analogix: Support eDP lane mapping
- ti-sn65dsi83: Support LVDS Channel B on SN65DSI84
- Select DRM_PANEL_BRIDGE for various drivers that require it
- add chrontel ch7218a support
panel:
- panel-edp: Support MNE007QS3-F, TM140VDXP15, and KD116N36-30NB-A001
- samsung-s6d16d0: Use mipi_dsi_*_multi() functions
- support Ilitek ILI7836A OLED plus DT bindings
- support Novatek NT36532 plus DT bindings
- convert several drivers to managed cleanup
- fix Kconfig selections
- edp:
- Add support for BOE NV140FHM-T0A
- Support CSOT MNE007QB1-1
- NV140WU2-M70
- ebbg-ft8719: Fix MODULE_LICENSE() string; Improve initialization
- samsung: Share test-key helpers
- ilitek-ili9882t: Support Ilitek IL79600A plus DT bindings
- simple: Support Truly TFT320240-229-E plus DT bindings; Support BOE
DV215FHM-R01 plus DT bindings
- Refactor struct drm_panel to contain struct drm_bridge plus fallout
in various panel drivers
- Add support for BOE Novatek NT51021, Retroid Pocket 6, Raydium
RM69220 DDIC panels, Sharp LQ138P1JX61 eDP, BOE NV140FHD-N43, AUO
B140HAN04.0, AUO 0x0db3, panels.
amdgpu:
- use AMD VSDB for freesync
- implement YUV-to-RGB with fixed-matrix colorop
- enable FRL for HDMI
- HDMI 2.1 freesync support
- HDMI 2.1 ALLM support
- HDMI 2.1 VRR support
- UALoE (UALink over Ethernet) support
- add syncobj_points to userq signal ioctl
- drop unused kunit tests
- NBIO/GC/MMHUB/SMU updates/fixes
- GPU spatial partitioning updates
- display kunit fixes
- userq fixes
- RGB quantization fixes
- DC RMCM refactor
- DP MST fixes
- USB4 fixes
- add new trace events
- Rework display instance handling
- stack frame size fixes for various compilers/configs
- VCN 4/5 reset fixes
- freesync updates
- cursor refactor
- Fix direct scanout alpha on some DRM_FORMATs
- Expand Mac reserved memory workaround
- Make runtime pm more fine grained
amdkfd:
- updates and fixes
- GC 10 CU occupancy support
radeon:
- eDP fix for DCE3.2 iMacs
xe:
- add drm_ras netlink error event support
- add memory page offlining support
- introduce error threshold to drm_ras
- fix stale GTT mappings on unmap
- reject page faults for non-page fault mode scratch VM
- enable CRI package and VRAM temperatures
- introduce cold reset recovery
- handle CRI+ power interval encoding
- VF migration for multi-queue
- handle exec queue teardown after hot unplug
- alerts and controller enabling modifications
- use IBCv3 on PTL
- VRAM health check
- report GT TDR and VM rebind faults using SIGID
- add multi_queue_active_lrca debugfs
- shrinker: Runtime PM reference for non-system memory
- guc: Add simple KLV decoder helpers
- debugfs: Expose per-engine idle status
- Keep walking on SVM eviction failure
- Nuke PTs only after unlinking contested VMAs
- limit sg segment size to PAGE_SIZE on Xen PV
- keep VF LMEM bar size low if no VFs
- CPU binds and ULLS on migration queue
- New PTL PCI ID
- Enable PXP for NVL-S
- Do not dma_fence_put zero fences in err_out path
- Refresh TTM LRU on SVM prefetch
- export device UID in sysfs
i915:
- rename GEN6_PCODE_DATA to match spec
- fix incorrect RCU teardown order
- fix potential UAF in command parsing
- avoid WARN splat during RPS boosting race
- use simpler min functions
- Fixes to make i915 work well with PREEMPT_RT
i915/display:
- Enable CMRR (Content Match Refresh Rate) in fixed-RR VRR path
- Switch DG2 MPLL to DPLL framework
- DP-HDMI PCON DSC fixes
- limit invalid joiner combinations
- CDCLK related fixes and refactor around PCODE integration
- Gate UHBR SST SDP splitting on sink caps
- add HDMI TMDS audio bandwidth check
- vswing/preemph override
- enable AS SDP Skip frames
- Handle negative configuration index on DP link caps for robustness
- Preparation for enabling SDR plane color pipeline
- An eDP quirk for HP Pavilion Plus
- Introduce PME (Power Management Event) support on display hotplug
- Handle VSC SDP revision 7 in unpack
msm:
- CI:
- Dropped sc7180 trogdor lazor from the CI
- Core:
- Fixed msm_ioremap for resources without a name
- Changed msm.separate_gpu_kms to default to auto selection
- GPU:
- Enable CLX (Current Limit eXtension) for gen8 to avoid exceeding
limits on CX/GX rails
- New GPUs: a830 (Pakala), a845 (Maili), a850 (Hawi), x2-85
(Mahua)
- Fix VBIF halt mask on a306, which was preventing runpm suspend
- Enable THP support for GEM buffers
- Add modparam to disable waiting on fences in shrinker
- Drop use of drm_prime_sg_to_page_array()
- a5xx: don't read the GPMU registers on GPUs without a GPMU
- a2xx/a3xx/a5xx: hangcheck progress detection
- a6xx: gmuwrapper runpm fix
- Calculate reported GMEM size based on active slices
- Split a6xx/a7xx/a8xx catalog
- DP:
- Picked up some preparation patches for the MST support
- Fixed reported status of the link training
- DPU:
- Fixed CRTC bandwidth computation
- Fixed DSC programming
- Fixed encoder disablement path
- DSI:
- Fixed VM leak in error path
- Indention fix
- MDP5:
- Added MSM8952 configuration
- Dropped incorrect cursor pipe on MSM8976/56
- HDMI:
- Small fixes
nouveau:
- improve runtime PM on R570 GSP firmware
- various fixes throughout the driver
- dispnv50: support 2.147 GHz pixel clock in GB20x
nova:
- add initial uapi concept
- add initial PRAMIN access support
- add GpuMm centralized memory manager
- add GPU VM and BAR1 support
- add GPU interrupts and GSP events support
- GSP messaging fixes
tyr:
- use bitfield!
- zero unsupported and newly added GPU info fields
- limit doorbell array to 17 entries
exynos:
- FIMD fixes
- Fix clock leak on resume error path
- Fix Sparse warnings by adding missing __iomem annotation
- VIDI cleanup
- Replace kmalloc() and copy_from_user() with memdup_user()
amdxdna:
- fix BO handling
- Support AIE2 rev 9
- Fix UAF access in scheduler fences
- Update workqueue interface
- expose busy time via fdinfo
ast:
- support 256-byte EDID
hyperv_drm:
- remove support for pre win10 hosts
komeda:
- fix GLB_CORE_ID usage
omap:
- report HDMI hotplug events to ASoC HDMI codec
panthor:
- provide gpu_cache_flush tracepoint
- improve dma_fence signalling latency
- improve locking
- export scheduling information via debugfs
- Validate user-space input against firmware limits
qaic:
- reject BOs that exceed maximum page count
- add missing include statements
verisilicon:
- fix hardware cursor offsets
vkms:
- implement YUV-to-RGB with fixed-matrix colorop
gma500:
- avoid unsupported ARGB formats in primary plane
hibmc:
- handle vblank interrupts correctly
ivpu:
- add DRM_IVPU_CAP_CMDQ_SET_PRIORITY
- support command-queue priority ioctl
- Simplify NULL-pointer handling in cleanup code
arcpgu:
- replace simple-display pipeline with regular atomic helpers
aspeed:
- replace simple-display pipeline with regular atomic helpers
gm12u320:
- replace simple-display pipeline with regular atomic helpers
imagination:
- various improvement to firmware interaction
- add job to pvr_job_submit_fw trace event
mali-dp:
- fix runtime PM leak
mcde:
- replace simple-display pipeline with regular atomic helpers
p111:
- replace simple-display pipeline with regular atomic helpers
- drop unsupported alpha formats from primary plane
rcar-du:
- support Renesas R-Car V4H DSC
- dsi: Support larger transfers with AXI memory
- Support RZ/G3L SoC
repaper:
- replace simple-display pipeline with regular atomic helpers
rockchip:
- dsi: improve PHY timings
ssd130x:
- support Solomon SSD1351 OLED plus DT bindings
- ssd133x: upgrade color format to RGB565
- ssd132x: Set correct hardware window when clearing screen
tve200:
- replace simple-display pipeline with regular atomic helpers
xen:
- replace simple-display pipeline with regular atomic helpers
v3d:
- improve job handling under perfmon
vc4:
- reliably reset V3D
- drop brcm,vc4-v3d compatible
virtio:
- fix damage handling
- Support ARGB8888 for virtio primary planes.
host1x:
- Support partitioning
imx:
- Replace simple-display with regular atomic helpers
mxsfb:
- Support bus formats plus DT bindings
tegra:
- improve syncobj handling on submit
panfrost:
- add Mali-G68 support
- improve GPU reset handling
rockchip:
- add HDMI 2.0 support to dw-hdmi-qp
- improve HPD handling"
* tag 'drm-next-2026-10-21' of https://gitlab.freedesktop.org/drm/kernel: (2324 commits)
drm/adp: Switch to drm_atomic_helper_connector_create_state
drm/malidp: Convert to atomic_create_state
drm/vc4: Switch to drm_atomic_helper_connector_create_state
drm/sysfb: Switch to drm_atomic_helper_connector_create_state
drm/solomon: ssd130x: Switch to drm_atomic_helper_connector_create_state
drm/imx: ipuv3: Switch to drm_atomic_helper_connector_create_state
drm/hyperv: Switch to drm_atomic_helper_connector_create_state
drm/bridge: megachips: Switch to drm_atomic_helper_connector_create_state
drm/bridge: lontium-lt8912b: Switch to drm_atomic_helper_connector_create_state
drm/arm: komeda: Switch to drm_atomic_helper_connector_create_state
drm/appletbdrm: Fix incorrect error message on encoder attach failure
drm/sun4i: hdmi: Convert to drmm_connector_hdmi_init()
drm/rockchip: rk3066_hdmi: Advertise HDMI 1.4 capabilities
drm/bridge: lontium-lt9611: Advertise HDMI 1.4 capabilities
drm/bridge: ite-it66121: Advertise HDMI 1.2 capabilities
drm/bridge: ite-it6263: Advertise HDMI 1.3 capabilities
drm/bridge: ite-it6263: Drop redundant .mode_valid hook
drm/bridge: inno-hdmi: Advertise HDMI 1.2 capabilities
drm/bridge: adv7511: Advertise HDMI 1.2 capabilities
drm/sched: Document entity->stopped is protected by entity->lock
...
DRM Rust changes for v7.4-rc1
- Cross-subsystem:
- I/O (shared from driver-core tree via signed tag rust-io-7.4-rc1):
- Reimplement register!() as a procedural macro, require matching
base types for register access, and replace relative registers
with typed I/O projections. Convert Nova, Tyr and the PCI sample
- Add AsRepr/AsReprMut conversions for I/O on compatible wrapper
types and transmute helpers with deferred size checks
- DMA (shared from driver-core tree via signed tag rust-dma-7.4-rc1):
- Tie Coherent, CoherentBox and CoherentHandle to the device's bound
lifetime, and allow scoped debugfs files backed by non-'static
data
- Allow auxiliary registration-data closures to return covariant
sub-fields and add UserSliceWriter::write_truncated()
- Implement Send and Sync for MapleTree
- Add PCI resource_flags() and IORESOURCE_MEM_64, and convert PCI IRQ
flags to impl_flags!()
- Add I/O view cast() with compile-time size and alignment checks
- DRM:
- Add Rust dma_fence abstractions with separate producer (DriverFence)
and consumer (Fence) types, per-context sequencing, signal callbacks
and preallocation. Additional backend operations remain follow-up
work.
- Initialize DRM registrations and their data in place, removing a
separate allocation
- Drop the unused flags argument from drm::Registration::new()
- Nova:
- UAPI and Cross Module API:
- Add NovaCoreApi and a lifetime-bound handle for auxiliary child
drivers, carried in nova-drm registration data
- Expose a render node and extensible INFO ioctl reporting GPU
architecture, opaque chip ID, usable VRAM and VRAM BAR sizes,
full and short GPU names, and GID, with size discovery and
truncation to the userspace buffer size
- Move BAR-size queries into GPU info, removing GETPARAM and
changing the UAPI
- PRAMIN access:
- Add typed CPU access to VRAM through the movable 1 MiB BAR0
PRAMIN window, with per-architecture support from Turing through
Blackwell
- Add GpuMm centralized memory manager, VramAddress type, aperture
documentation and optional probe-time self-tests under
CONFIG_NOVA_CORE_SELFTESTS
- GPU virtual memory and BAR1:
- Add VRAM buddy allocation, TLB flushing, MMU v2/v3 page-table
types with trait-based generics (PteOps, PdeOps, DualPdeOps,
MmuConfig) and a generic walker
- Add maple-tree virtual address tracking and multi-page mapping,
separating allocation from mapping execution
- Add CPU access to mapped VRAM through BAR1 and memory-management
self-tests; handle 64-bit BAR0 when locating BAR1
- GPU interrupts and GSP events:
- Add GIN (GPU Interrupt and Notification) interrupt-tree support
with MSI-X, MSI fallback and per-architecture rearming
- Drain GSP events between commands via a threaded SWGEN0 handler
- Report OS errors, robust-channel notifications and unknown
messages without aborting command waits; hold the queue lock and
use one deadline per wait
- Disable GSP event interrupts on persistent falcon faults or
drain errors
- Add a delivery/rearm self-test, interrupt-tree KUnit coverage
and interrupt-controller documentation
- GSP messaging fixes:
- Queue setup RPCs before GSP-RM boot
- Correct DMA barriers in both queue directions
- Firmware and transport:
- Extract a reusable radix3 buffer mapper; zero-pad page-table
levels to whole pages to prevent booter reads of stale padding
- Correct GSP-FMC naming and boot-flow documentation
- Set MCTP header version 1 for FSP messages and retain the
command queue's BAR0 reference
- Resource handling:
- Replace unnecessary BarUser reference counting with in-place
ownership and borrowed access; consolidate probe initialization
- Declare an unlimited DMA maximum segment size
- Tyr:
- Use bitfield!() for firmware section flags and memory attributes
that do not describe registers
- Zero unsupported and newly added GPU-info fields, and limit the
doorbell array to 17 entries to fit the mapped register region
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: "Danilo Krummrich" <dakr@kernel.org>
Link: https://patch.msgid.link/DM371PN4TBJT.3LY1B0EYWSI4@kernel.org
The abstractions for pr_*_ratelimited! need to construct a global `struct ratelimit_state`, which contains a `raw_spinlock_t` field. Thus, add a const constructor for the `raw_spinlock_t` type. The SPINLOCK_OWNER_INIT constant isn't mirrored via a const helper because bindgen generates a 'static mut' instead of a constant from the pointer constant., The __ARCH_SPIN_LOCK_UNLOCKED constant cannot be translated by bindgen because it's a define for a struct without type annotations, so it's explicitly declared in Rust. Reviewed-by: Boqun Feng <boqun@kernel.org> Reviewed-by: Carlos Llamas <cmllamas@google.com> Acked-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20261007-pr-ratelimited-v6-2-f14accd4ea3b@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Pull timekeeping updates from Andreas Hindborg: - Warn and assert when passing out-of-range inputs to 'fsleep' and 'udelay'. - Rename 'ClockSource' to 'ClockId' to better align with naming conventions in C kernel. - Make 'CONFIG_HZ' value available as 'bindings::HZ'. - Add a conversion method to convert 'Delta' to 'jiffies' for use in timeout arguments. - Add implementation detail documentation for 'HrTimer'. * tag 'rust-timekeeping-for-v7.4-rc1' of https://github.com/Rust-for-Linux/linux: rust: hrtimer: document handle based design rationale rust: time: add Delta::to_jiffies_timeout() for timeout conversion rust: bindings: set HZ to CONFIG_HZ rust: time: rename ClockSource trait to ClockId rust: time: warn and assert out-of-range input in fsleep() and udelay()
Commit 2b6a3f061f11 ("mm: declare VMA flags by bit") added a number of
overrides to the rust bindings helper as the change performed in the commit
caused rust bindgen to not be able to automatically determine values of
VMA flags.
However a typo was introduced leaving VM_MAYSHARE to be incorrectly
interpreted as VM_MAYEXEC in rust code. This patch fixes the typo.
Fixes: 2b6a3f061f11 ("mm: declare VMA flags by bit")
Reported-by: Chris Mason <clm@meta.com>
Closes: https://lore.kernel.org/all/20260113185142.254821-1-clm@meta.com/
Cc: stable@vger.kernel.org
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: wang lian <lianux.mm@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260113192949.689834-1-lorenzo.stoakes@oracle.com
[ Reworded to improve title and to fix typo. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
include/uapi/asm-generic/param.h defines HZ as __USER_HZ and include/asm-generic/param.h then sets it to CONFIG_HZ. bindgen keeps the first definition of a macro and ignores a later #undef, so the generated binding is __USER_HZ. Redefine HZ in rust/bindings/lib.rs, the same way compat_ptr_ioctl is redefined there. Nothing in the tree reads bindings::HZ today, so this prevents accidental misuse rather than fixing a bug. Suggested-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Link: https://msgid.link/20260924232530.446588-2-tomo@flapping.org Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Linux 7.3-rc4 Requested by Philipp Stanner for 2ab510e63197360945f915dd5631a77c63ac6b27 would be needed as a groundlayer for further patches that extend the locking in drm_sched Signed-off-by: Dave Airlie <airlied@redhat.com>
Move drm_plane_helper_display_panic_screen() and the existing panic-
display code into drm_panic_helper.c. Rename symbols accordingly.
Also update the QR-related code and the bindings accordingly.
Link the rsp. object file into drm_kms_helper.ko. Eventually the code
will become a DRM drawing library, together with DRM's format and draw
helpers. This requires more preparation. until then, KMS helpers serve
as a module. All DRM drivers link it anyway.
Add a new section about drawing helpers to the documentation of the KMS
helpers. List format and panic helpers there.
v2:
- fix dependencies on other DRM modules (Randy, Sashiko)
- provide placeholders for drm_panic_helper_{init,exit}() (Sashiko)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patch.msgid.link/20260911124540.279841-14-tzimmermann@suse.de
Starting with bindgen 0.73.2 [1], `#[allow(unnecessary_transmutes)]`
are used, even when `--rust-target 1.85` is passed.
However, the lint was introduced in Rust 1.88.0. Thus building with
older Rust versions warns like:
error: unknown lint: `unnecessary_transmutes`
--> rust/uapi/uapi_generated.rs:26294:13
|
26294 | #[allow(unnecessary_transmutes)]
| ^^^^^^^^^^^^^^^^^^^^^^
|
= note: `-D unknown-lints` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(unknown_lints)]`
Thus allow `unknown_lints` in the generated bindings -- only when building
with older Rust versions.
I have asked upstream if this is intentional [1], i.e. if we are supposed
to always allow unknown lints in case `bindgen` uses such attributes,
or whether it is an oversight.
[ Emilio said it wasn't intentional -- we will work around it for now
on the kernel side. - Miguel ]
Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Cc: Emilio Cobos Álvarez <emilio@crisal.io>
Link: https://github.com/rust-lang/rust-bindgen/pull/3455#issuecomment-5588526559 [1]
Assisted-by: LLM
Link: https://patch.msgid.link/20260908170539.345207-1-ojeda@kernel.org
[ Removed the `cfg` for `allow(unnecessary_transmutes)` as suggested by
Gary. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
DMA fences are synchronisation primitives that will be needed by all
Rust GPU drivers.
The dma_fence framework sets a number of rules, notably:
- fences must only be signaled once
- all fences must be signaled at some point
- fence error codes must only be set before signaling
- every pointer to a fence must be backed by a reference
All those rules are being addressed by these abstractions.
To cleanly decouple fence issuers and consumers, two types are provided:
- DriverFence: the only fence type that can be signaled and that
carries driver-specific data.
- Fence: the fence type to be shared with other drivers and / or
userspace. The only type callbacks can be registered on.
Cannot be signaled.
Hereby, a Fence lives in the same chunk of memory as a DriverFence. Both
share the refcount of the underlying C dma_fence. Since this
implementation does not provide a custom dma_fence_backend_ops.release()
function, the memory is freed by the dma_fence backend once the refcount
drops to 0.
To create a DriverFence, the user must first allocate a
DriverFenceAllocation, so that the creation of the DriverFence later on
can always succeed. Otherwise, deadlocks could occur if fences need to
be created in a GPU job submission path.
Synchronization is ensured by the dma_fence backend.
All DriverFence's created through this abstraction must be signaled by
the creator with an error code. In case a DriverFence drops without
being signaled beforehand, it is signaled with -ECANCELLED as its
error and a warning is printed. This allows the Rust abstraction to very
cleanly decouple fence issuer and consumer by relying on the decoupling
mechanisms in the C backend, which ensures through RCU and the
'signaled' fence-flag that dma_fence_backend_ops functions cannot
access the potentially unloaded driver code anymore.
Signalling fences on drop thus grants many advantages. Not signaling
fences on drop would risk deadlock and does not grant real advantages:
By definition only the drivers can ensure that a fence always represents
the hardware's state correctly.
This implementation models a DmaFenceContext object on which fences are
to be created, thereby ensuring correct sequence numbering according to
the timeline.
dma_fence supports a variety of callbacks. The mandatory callbacks
(get_timeline_name() and get_driver_name()) are implemented in this
patch. For convenience, they store those name parameters in the fence
context, saving the driver from implementing these two callbacks.
Support for other callbacks (like for hardware signaling) is prepared
for through the fact that both DriverFence and Fence live in the same
allocation, allowing for usage of container_of from the callback to
access the driver-specific data.
It is expected that other callbacks, added in the future, also mostly
operate on the generic data in the FenceContext. To make this safe, the
implementation ensures through a lifetime that a DriverFence cannot
outlive its FenceContext.
Synchronization for dma_fence_ops callbacks is ensured by only running the
Rust deconstructor delayed with call_rcu(), which prevents UAF-bugs
should a DriverFence drop while a Fence callback is currently operating
on the associated driver data. Since they can also operate on the
FenceContext's data, its drop implementation also performs the necessary
delay with rcu_barrier().
An additional issue discovered during the review process of this code is
that there is (currently) no mechanism in Rust to prevent someone from
circumventing the DriverFence's FenceContext-reference's lifetime by
"forgetting" the fence, e.g. with core::mem::forget(). This would enable
UAF bugs on the FenceContext. Throw a panic if this happens and document
a path towards a more robust solution.
Add abstractions for dma_fence in Rust.
Signed-off-by: Philipp Stanner <phasta@kernel.org>
Tested-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Link: https://patch.msgid.link/20260905085343.1827305-3-phasta@kernel.org
[ In dma_fence_callback(), split combined unsafe block into separate
blocks for container_of!() and pointer dereference. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>