kernel/linux.git/rust/helpers, branch v6.19.11

rust: bitops: fix missing _find_* functions on 32-bit ARM

2026-01-14T03:16:39+00:00

On 32-bit ARM, you may encounter linker errors such as this one: ld.lld: error: undefined symbol: _find_next_zero_bit >>> referenced by rust_binder_main.43196037ba7bcee1-cgu.0 >>> drivers/android/binder/rust_binder_main.o:(::insert_or_update_handle) in archive vmlinux.a >>> referenced by rust_binder_main.43196037ba7bcee1-cgu.0 >>> drivers/android/binder/rust_binder_main.o:(::insert_or_update_handle) in archive vmlinux.a This error occurs because even though the functions are declared by include/linux/find.h, the definition is #ifdef'd out on 32-bit ARM. This is because arch/arm/include/asm/bitops.h contains: #define find_first_zero_bit(p,sz) _find_first_zero_bit_le(p,sz) #define find_next_zero_bit(p,sz,off) _find_next_zero_bit_le(p,sz,off) #define find_first_bit(p,sz) _find_first_bit_le(p,sz) #define find_next_bit(p,sz,off) _find_next_bit_le(p,sz,off) And the underscore-prefixed function is conditional on #ifndef of the non-underscore-prefixed name, but the declaration in find.h is *not* conditional on that #ifndef. To fix the linker error, we ensure that the symbols in question exist when compiling Rust code. We do this by defining them in rust/helpers/ whenever the normal definition is #ifndef'd out. Note that these helpers are somewhat unusual in that they do not have the rust_helper_ prefix that most helpers have. Adding the rust_helper_ prefix does not compile, as 'bindings::_find_next_zero_bit()' will result in a call to a symbol called _find_next_zero_bit as defined by include/linux/find.h rather than a symbol with the rust_helper_ prefix. This is because when a symbol is present in both include/ and rust/helpers/, the one from include/ wins under the assumption that the current configuration is one where that helper is unnecessary. This heuristic fails for _find_next_zero_bit() because the header file always declares it even if the symbol does not exist. The functions still use the __rust_helper annotation. This lets the wrapper function be inlined into Rust code even if full kernel LTO is not used once the patch series for that feature lands. Yury: arches are free to implement they own find_bit() functions. Most rely on generic implementation, but arm32 and m86k - not; so they require custom handling. Alice confirmed it fixes the build for both. Cc: stable@vger.kernel.org Fixes: 6cf93a9ed39e ("rust: add bindings for bitops.h") Reported-by: Andreas Hindborg Closes: https://rust-for-linux.zulipchat.com/#narrow/channel/x/topic/x/near/561677301 Tested-by: Andreas Hindborg Reviewed-by: Dirk Behme Signed-off-by: Alice Ryhl Signed-off-by: Yury Norov (NVIDIA)

rust: dma: add helpers for architectures without CONFIG_HAS_DMA

2025-12-16T12:20:14+00:00

Add dma_set_mask(), dma_set_coherent_mask(), dma_map_sgtable(), and dma_max_mapping_size() helpers to fix a build error when CONFIG_HAS_DMA is not enabled. Note that when CONFIG_HAS_DMA is enabled, they are included in both bindings_generated.rs and bindings_helpers_generated.rs. The former takes precedence so behavior remains unchanged in that case. This fixes the following build error on UML: error[E0425]: cannot find function `dma_set_mask` in crate `bindings` --> rust/kernel/dma.rs:46:38 | 46 | to_result(unsafe { bindings::dma_set_mask(self.as_ref().as_raw(), mask.value()) }) | ^^^^^^^^^^^^ help: a function with a similar name exists: `xa_set_mark` | ::: rust/bindings/bindings_generated.rs:24690:5 | 24690 | pub fn xa_set_mark(arg1: *mut xarray, index: ffi::c_ulong, arg2: xa_mark_t); | ---------------------------------------------------------------------------- similarly named function `xa_set_mark` defined here error[E0425]: cannot find function `dma_set_coherent_mask` in crate `bindings` --> rust/kernel/dma.rs:63:38 | 63 | to_result(unsafe { bindings::dma_set_coherent_mask(self.as_ref().as_raw(), mask.value()) }) | ^^^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: `dma_coherent_ok` | ::: rust/bindings/bindings_generated.rs:52745:5 | 52745 | pub fn dma_coherent_ok(dev: *mut device, phys: phys_addr_t, size: usize) -> bool_; | ---------------------------------------------------------------------------------- similarly named function `dma_coherent_ok` defined here error[E0425]: cannot find function `dma_map_sgtable` in crate `bindings` --> rust/kernel/scatterlist.rs:212:23 | 212 | bindings::dma_map_sgtable(dev.as_raw(), sgt.as_ptr(), dir.into(), 0) | ^^^^^^^^^^^^^^^ help: a function with a similar name exists: `dma_unmap_sgtable` | ::: rust/bindings/bindings_helpers_generated.rs:1351:5 | 1351 | / pub fn dma_unmap_sgtable( 1352 | | dev: *mut device, 1353 | | sgt: *mut sg_table, 1354 | | dir: dma_data_direction, 1355 | | attrs: ffi::c_ulong, 1356 | | ); | |______- similarly named function `dma_unmap_sgtable` defined here error[E0425]: cannot find function `dma_max_mapping_size` in crate `bindings` --> rust/kernel/scatterlist.rs:356:52 | 356 | let max_segment = match unsafe { bindings::dma_max_mapping_size(dev.as_raw()) } { | ^^^^^^^^^^^^^^^^^^^^ not found in `bindings` error: aborting due to 4 previous errors Cc: stable@vger.kernel.org # v6.17+ Fixes: 101d66828a4ee ("rust: dma: add DMA addressing capabilities") Signed-off-by: FUJITA Tomonori Reviewed-by: David Gow Reviewed-by: Alice Ryhl Link: https://patch.msgid.link/20251204160639.364936-1-fujita.tomonori@gmail.com [ Use relative paths in the error splat; add 'dma' prefix. - Danilo ] Signed-off-by: Danilo Krummrich

Merge tag 'usb-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

2025-12-07T02:42:12+00:00

Pull USB/Thunderbolt updates from Greg KH: "Here is the big set of USB and Thunderbolt driver updates for 6.19-rc1. Nothing major here, just lots of tiny updates for most of the common USB drivers. Included in here are: - more xhci driver updates and fixes - Thunderbolt driver cleanups - usb serial driver updates - typec driver updates - USB tracepoint additions - dwc3 driver updates, including support for Apple hardware - lots of other smaller driver updates and cleanups All of these have been in linux-next for a while with no reported issues" * tag 'usb-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (161 commits) usb: gadget: tegra-xudc: Always reinitialize data toggle when clear halt USB: serial: option: move Telit 0x10c7 composition in the right place USB: serial: option: add Telit Cinterion FE910C04 new compositions usb: typec: ucsi: fix use-after-free caused by uec->work usb: typec: ucsi: fix probe failure in gaokun_ucsi_probe() usb: dwc3: core: Remove redundant comment in core init usb: phy: Initialize struct usb_phy list_head USB: serial: option: add Foxconn T99W760 usb: usb-storage: No additional quirks need to be added to the EL-R12 optical drive. usb: typec: hd3ss3220: Enable VBUS based on ID pin state dt-bindings: usb: ti,hd3ss3220: Add support for VBUS based on ID state usb: typec: anx7411: add WQ_PERCPU to alloc_workqueue users USB: add WQ_PERCPU to alloc_workqueue users dt-bindings: usb: dwc3-xilinx: Describe the reset constraint for the versal platform drivers/usb/storage: use min() instead of min_t() usb: raw-gadget: cap raw_io transfer length to KMALLOC_MAX_SIZE usb: ohci-da8xx: remove unused platform data usb: gadget: functionfs: use dma_buf_unmap_attachment_unlocked() helper usb: uas: reduce time under spinlock usb: dwc3: eic7700: Add EIC7700 USB driver ...

Merge tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-12-06T22:01:20+00:00

Pull non-MM updates from Andrew Morton: - "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko) fixes a build issue and does some cleanup in ib/sys_info.c - "Implement mul_u64_u64_div_u64_roundup()" (David Laight) enhances the 64-bit math code on behalf of a PWM driver and beefs up the test module for these library functions - "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich) makes BPF symbol names, sizes, and line numbers available to the GDB debugger - "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang) adds a sysctl which can be used to cause additional info dumping when the hung-task and lockup detectors fire - "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu) adds a general base64 encoder/decoder to lib/ and migrates several users away from their private implementations - "rbree: inline rb_first() and rb_last()" (Eric Dumazet) makes TCP a little faster - "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin) reworks the KEXEC Handover interfaces in preparation for Live Update Orchestrator (LUO), and possibly for other future clients - "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin) increases the flexibility of KEXEC Handover. Also preparation for LUO - "Live Update Orchestrator" (Pasha Tatashin) is a major new feature targeted at cloud environments. Quoting the cover letter: This series introduces the Live Update Orchestrator, a kernel subsystem designed to facilitate live kernel updates using a kexec-based reboot. This capability is critical for cloud environments, allowing hypervisors to be updated with minimal downtime for running virtual machines. LUO achieves this by preserving the state of selected resources, such as memory, devices and their dependencies, across the kernel transition. As a key feature, this series includes support for preserving memfd file descriptors, which allows critical in-memory data, such as guest RAM or any other large memory region, to be maintained in RAM across the kexec reboot. Mike Rappaport merits a mention here, for his extensive review and testing work. - "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain) moves the kexec and kdump sysfs entries from /sys/kernel/ to /sys/kernel/kexec/ and adds back-compatibility symlinks which can hopefully be removed one day - "kho: fixes for vmalloc restoration" (Mike Rapoport) fixes a BUG which was being hit during KHO restoration of vmalloc() regions * tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits) calibrate: update header inclusion Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()" vmcoreinfo: track and log recoverable hardware errors kho: fix restoring of contiguous ranges of order-0 pages kho: kho_restore_vmalloc: fix initialization of pages array MAINTAINERS: TPM DEVICE DRIVER: update the W-tag init: replace simple_strtoul with kstrtoul to improve lpj_setup KHO: fix boot failure due to kmemleak access to non-PRESENT pages Documentation/ABI: new kexec and kdump sysfs interface Documentation/ABI: mark old kexec sysfs deprecated kexec: move sysfs entries to /sys/kernel/kexec test_kho: always print restore status kho: free chunks using free_page() instead of kfree() selftests/liveupdate: add kexec test for multiple and empty sessions selftests/liveupdate: add simple kexec-based selftest for LUO selftests/liveupdate: add userspace API selftests docs: add documentation for memfd preservation via LUO mm: memfd_luo: allow preserving memfd liveupdate: luo_file: add private argument to store runtime state mm: shmem: export some functions to internal.h ...

Merge tag 'driver-core-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core

2025-12-06T05:29:02+00:00

Pull driver core updates from Danilo Krummrich: "Arch Topology: - Move parse_acpi_topology() from arm64 to common code for reuse in RISC-V CPU: - Expose housekeeping CPUs through /sys/devices/system/cpu/housekeeping - Print a newline (or 0x0A) instead of '(null)' reading /sys/devices/system/cpu/nohz_full when nohz_full= is not set debugfs - Remove (broken) 'no-mount' mode - Remove redundant access mode checks in debugfs_get_tree() and debugfs_create_*() functions Devres: - Remove unused devm_free_percpu() helper - Move devm_alloc_percpu() from device.h to devres.h Firmware Loader: - Replace simple_strtol() with kstrtoint() - Do not call cancel_store() when no upload is in progress kernfs: - Increase struct super_block::maxbytes to MAX_LFS_FILESIZE - Fix a missing unwind path in __kernfs_new_node() Misc: - Increase the name size in struct auxiliary_device_id to 40 characters - Replace system_unbound_wq with system_dfl_wq and add WQ_PERCPU to alloc_workqueue() Platform: - Replace ERR_PTR() with IOMEM_ERR_PTR() in platform ioremap functions Rust: - Auxiliary: - Unregister auxiliary device on parent device unbind - Move parent() to impl Device; implement device context aware parent() for Device - Illustrate how to safely obtain a driver's device private data when calling from an auxiliary driver into the parant device driver - DebugFs: - Implement support for binary large objects - Device: - Let probe() return the driver's device private data as pinned initializer, i.e. impl PinInit - Implement safe accessor for a driver's device private data for Device (returned reference can't out-live driver binding and guarantees the correct private data type) - Implement AsBusDevice trait, to be used by class device abstractions to derive the bus device type of the parent device - DMA: - Store raw pointer of allocation as NonNull - Use start_ptr() and start_ptr_mut() to inherit correct mutability of self - FS: - Add file::Offset type alias - I2C: - Add abstractions for I2C device / driver infrastructure - Implement abstractions for manual I2C device registrations - I/O: - Use "kernel vertical" style for imports - Define ResourceSize as resource_size_t - Move ResourceSize to top-level I/O module - Add type alias for phys_addr_t - Implement Rust version of read_poll_timeout_atomic() - PCI: - Use "kernel vertical" style for imports - Move I/O and IRQ infrastructure to separate files - Add support for PCI interrupt vectors - Implement TryInto> for IrqVector<'a> to convert an IrqVector bound to specific pci::Device into an IrqRequest bound to the same pci::Device's parent Device - Leverage pin_init_scope() to get rid of redundant Result in IRQ methods - PinInit: - Add {pin_}init_scope() to execute code before creating an initializer - Platform: - Leverage pin_init_scope() to get rid of redundant Result in IRQ methods - Timekeeping: - Implement abstraction of udelay() - Uaccess: - Implement read_slice_partial() and read_slice_file() for UserSliceReader - Implement write_slice_partial() and write_slice_file() for UserSliceWriter sysfs: - Prepare the constification of struct attribute" * tag 'driver-core-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core: (75 commits) rust: pci: fix build failure when CONFIG_PCI_MSI is disabled debugfs: Fix default access mode config check debugfs: Remove broken no-mount mode debugfs: Remove redundant access mode checks driver core: Check drivers_autoprobe for all added devices driver core: WQ_PERCPU added to alloc_workqueue users driver core: replace use of system_unbound_wq with system_dfl_wq tick/nohz: Expose housekeeping CPUs in sysfs tick/nohz: avoid showing '(null)' if nohz_full= not set sysfs/cpu: Use DEVICE_ATTR_RO for nohz_full attribute kernfs: fix memory leak of kernfs_iattrs in __kernfs_new_node fs/kernfs: raise sb->maxbytes to MAX_LFS_FILESIZE mod_devicetable: Bump auxiliary_device_id name size sysfs: simplify attribute definition macros samples/kobject: constify 'struct foo_attribute' samples/kobject: add is_visible() callback to attribute group sysfs: attribute_group: enable const variants of is_visible() sysfs: introduce __SYSFS_FUNCTION_ALTERNATIVE() sysfs: transparently handle const pointers in ATTRIBUTE_GROUPS() sysfs: attribute_group: allow registration of const attribute ...

rust: pci: fix build failure when CONFIG_PCI_MSI is disabled

2025-12-03T11:24:47+00:00

When CONFIG_PCI_MSI is disabled pci_alloc_irq_vectors() and pci_free_irq_vectors() are defined as inline functions and hence require a Rust helper. error[E0425]: cannot find function `pci_alloc_irq_vectors` in crate `bindings` --> rust/kernel/pci/irq.rs:144:23 | 144 | ...s::pci_alloc_irq_vectors(dev.as_raw(), min_vecs, max_vecs, irq_types.as_raw()) | ^^^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: `pci_irq_vector` | ::: .../rust/bindings/bindings_helpers_generated.rs:1197:5 | 1197 | pub fn pci_irq_vector(pdev: *mut pci_dev, nvec: ffi::c_uint) -> ffi::c_int; | --------------------------------------------------------------------------- similarly named function `pci_irq_vector` defined here error[E0425]: cannot find function `pci_free_irq_vectors` in crate `bindings` --> rust/kernel/pci/irq.rs:170:28 | 170 | unsafe { bindings::pci_free_irq_vectors(self.dev.as_raw()) }; | ^^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: `pci_irq_vector` | ::: .../rust/bindings/bindings_helpers_generated.rs:1197:5 | 1197 | pub fn pci_irq_vector(pdev: *mut pci_dev, nvec: ffi::c_uint) -> ffi::c_int; | --------------------------------------------------------------------------- similarly named function `pci_irq_vector` defined here error: aborting due to 2 previous errors Fix this by adding the corresponding helpers. Fixes: 340ccc973544 ("rust: pci: Allocate and manage PCI interrupt vectors") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202512012238.YgVvRRUx-lkp@intel.com/ Reviewed-by: Alice Ryhl Reviewed-by: Joel Fernandes Link: https://patch.msgid.link/20251202210501.40998-1-dakr@kernel.org Signed-off-by: Danilo Krummrich

rbtree: inline rb_last()

2025-11-27T22:24:30+00:00

This is a very small function, inlining it saves cpu cycles in TCP by reducing register pressure and removing call/ret overhead. It also reduces vmlinux text size by 122 bytes on a typical x86_64 build. Before: size vmlinux text data bss dec hex filename 34811781 22177365 5685248 62674394 3bc55da vmlinux After: size vmlinux text data bss dec hex filename 34811659 22177365 5685248 62674272 3bc5560 vmlinux [ojeda@kernel.org: fix rust build] Link: https://lkml.kernel.org/r/20251120085518.1463498-1-ojeda@kernel.org Link: https://lkml.kernel.org/r/20251114140646.3817319-3-edumazet@google.com Signed-off-by: Eric Dumazet Signed-off-by: Miguel Ojeda Reviewed-by: Kuan-Wei Chiu Cc: Jakub Kacinski Cc: Neal Cardwell Cc: Paolo Abeni Cc: Alice Ryhl Cc: Stehen Rothwell Signed-off-by: Andrew Morton

rbtree: inline rb_first()

2025-11-27T22:24:30+00:00

Patch series "rbree: inline rb_first() and rb_last()". Inline these two small helpers, heavily used in TCP and FQ packet scheduler, and in many other places. This reduces kernel text size, and brings an 1.5 % improvement on network TCP stress test. This patch (of 2): This is a very small function, inlining it saves cpu cycles by reducing register pressure and removing call/ret overhead. It also reduces vmlinux text size by 744 bytes on a typical x86_64 build. Before: size vmlinux text data bss dec hex filename 34812525 22177365 5685248 62675138 3bc58c2 vmlinux After: size vmlinux text data bss dec hex filename 34811781 22177365 5685248 62674394 3bc55da vmlinux [ojeda@kernel.org: fix rust build] Link: https://lkml.kernel.org/r/20251120085518.1463498-1-ojeda@kernel.org Link: https://lkml.kernel.org/r/20251114140646.3817319-1-edumazet@google.com Link: https://lkml.kernel.org/r/20251114140646.3817319-2-edumazet@google.com Signed-off-by: Eric Dumazet Signed-off-by: Miguel Ojeda Reviewed-by: Kuan-Wei Chiu Cc: Jakub Kacinski Cc: Neal Cardwell Cc: Paolo Abeni Cc: Alice Ryhl Cc: Stehen Rothwell Signed-off-by: Andrew Morton

uaccess: decouple INLINE_COPY_FROM_USER and CONFIG_RUST

2025-11-12T18:00:16+00:00

Commit 1f9a8286bc0c ("uaccess: always export _copy_[from|to]_user with CONFIG_RUST") exports _copy_{from,to}_user() unconditionally, if RUST is enabled. This pollutes exported symbols namespace, and spreads RUST ifdefery in core files. It's better to declare a corresponding helper under the rust/helpers, similarly to how non-underscored copy_{from,to}_user() is handled. [yury.norov@gmail.com: drop rust part of comment for _copy_from_user(), per Alice] Link: https://lkml.kernel.org/r/20251024154754.99768-1-yury.norov@gmail.com Link: https://lkml.kernel.org/r/20251023171607.1171534-1-yury.norov@gmail.com Signed-off-by: Yury Norov (NVIDIA) Acked-by: Arnd Bergmann Acked-by: Miguel Ojeda Reviewed-by: Alice Ryhl Tested-by: Alice Ryhl Cc: Alex Gaynor Cc: Andreas Hindborg Cc: Björn Roy Baron Cc: Boqun Feng Cc: Danilo Krummrich Cc: Gary Guo Cc: John Hubbard Cc: Trevor Gross Signed-off-by: Andrew Morton

rust: pwm: Add Kconfig and basic data structures

2025-11-07T09:03:54+00:00

Introduce the foundational support for PWM abstractions in Rust. This commit adds the `RUST_PWM_ABSTRACTIONS` Kconfig option to enable the feature, along with the necessary build-system support and C helpers. It also introduces the first set of safe wrappers for the PWM subsystem, covering the basic data carrying C structs and enums: - `Polarity`: A safe wrapper for `enum pwm_polarity`. - `Waveform`: A wrapper for `struct pwm_waveform`. - `State`: A wrapper for `struct pwm_state`. These types provide memory safe, idiomatic Rust representations of the core PWM data structures and form the building blocks for the abstractions that will follow. Tested-by: Drew Fustini Reviewed-by: Daniel Almeida Reviewed-by: Elle Rhumsaa Signed-off-by: Michal Wilczynski Link: https://patch.msgid.link/20251016-rust-next-pwm-working-fan-for-sending-v16-2-a5df2405d2bd@samsung.com Signed-off-by: Uwe Kleine-König