mirror of
https://github.com/torvalds/linux.git
synced 2026-07-31 19:47:08 +02:00
Linux kernel source tree
5d9fb42f05
Amery Hung says: ==================== Support associating BPF programs with struct_ops Hi, This patchset adds a new BPF command BPF_PROG_ASSOC_STRUCT_OPS to the bpf() syscall to allow associating a BPF program with a struct_ops. The command is introduced to address a emerging need from struct_ops users. As the number of subsystems adopting struct_ops grows, more users are building their struct_ops-based solution with some help from other BPF programs. For example, scx_layer uses a syscall program as a user space trigger to refresh layers [0]. It also uses tracing program to infer whether a task is using GPU and needs to be prioritized [1]. In these use cases, when there are multiple struct_ops instances, the struct_ops kfuncs called from different BPF programs, whether struct_ops or not needs to be able to refer to a specific one, which currently is not possible. The new BPF command will allow users to explicitly associate a BPF program with a struct_ops map. The libbpf wrapper can be called after loading programs and before attaching programs and struct_ops. Internally, it will set prog->aux->st_ops_assoc to the struct_ops map. struct_ops kfuncs can then get the associated struct_ops struct by calling bpf_prog_get_assoc_struct_ops() with prog->aux, which can be acquired from a "__prog" argument. The value of the special argument will be fixed up by the verifier during verification. The command conceptually associates the implementation of BPF programs with struct_ops map, not the attachment. A program associated with the map will take a refcount of it so that st_ops_assoc always points to a valid struct_ops struct. struct_ops implementers can use the helper, bpf_prog_get_assoc_struct_ops to get the pointer. The returned struct_ops if not NULL is guaranteed to be valid and initialized. However, it is not guaranteed that the struct_ops is attached. The struct_ops implementer still need to take steps to track and check the state of the struct_ops in kdata, if the use case demand the struct_ops to be attached. We can also consider support associating struct_ops link with BPF programs, which on one hand make struct_ops implementer's job easier, but might complicate libbpf workflow and does not apply to legacy struct_ops attachment. [0] https://github.com/sched-ext/scx/blob/main/scheds/rust/scx_layered/src/bpf/main.bpf.c#L557 [1] https://github.com/sched-ext/scx/blob/main/scheds/rust/scx_layered/src/bpf/main.bpf.c#L754 --- v7 -> v8 - Fix libbpf return (Andrii) - Follow kfunc _impl suffic naming convention in selftest (Alexei) Link: https://lore.kernel.org/bpf/20251121231352.4032020-1-ameryhung@gmail.com/ v6 -> v7 - Drop the guarantee that bpf_prog_get_assoc_struct_ops() will always return an initialized struct_ops (Martin) - Minor misc. changes in selftests Link: https://lore.kernel.org/bpf/20251114221741.317631-1-ameryhung@gmail.com/ v5 -> v6 - Drop refcnt bumping for async callbacks and add RCU annotation (Martin) - Fix libbpf bug and update comments (Andrii) - Fix refcount bug in bpf_prog_assoc_struct_ops() (AI) Link: https://lore.kernel.org/bpf/20251104172652.1746988-1-ameryhung@gmail.com/ v4 -> v5 - Simplify the API for getting associated struct_ops and dont't expose struct_ops map lifecycle management (Andrii, Alexei) Link: https://lore.kernel.org/bpf/20251024212914.1474337-1-ameryhung@gmail.com/ v3 -> v4 - Fix potential dangling pointer in timer callback. Protect st_ops_assoc with RCU. The get helper now needs to be paired with bpf_struct_ops_put() - The command should only increase refcount once for a program (Andrii) - Test a struct_ops program reused in two struct_ops maps - Test getting associated struct_ops in timer callback Link: https://lore.kernel.org/bpf/20251017215627.722338-1-ameryhung@gmail.com/ v2 -> v3 - Change the type of st_ops_assoc from void* (i.e., kdata) to bpf_map (Andrii) - Fix a bug that clears BPF_PTR_POISON when a struct_ops map is freed (Andrii) - Return NULL if the map is not fully initialized (Martin) - Move struct_ops map refcount inc/dec into internal helpers (Martin) - Add libbpf API, bpf_program__assoc_struct_ops (Andrii) Link: https://lore.kernel.org/bpf/20251016204503.3203690-1-ameryhung@gmail.com/ v1 -> v2 - Poison st_ops_assoc when reusing the program in more than one struct_ops maps and add a helper to access the pointer (Andrii) - Minor style and naming changes (Andrii) Link: https://lore.kernel.org/bpf/20251010174953.2884682-1-ameryhung@gmail.com/ --- ==================== Link: https://patch.msgid.link/20251203233748.668365-1-ameryhung@gmail.com Signed-off-by: Andrii Nakryiko <andrii@kernel.org> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst