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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
| commit | cf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch) | |
| tree | 757a3d280760c654767631cab5ad8af2d86d1848 /Documentation/bpf/maps.rst | |
| download | linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip | |
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij:
"Core changes:
- Use the non-blocking mux_state_try_select() in the generic MUX pin
control back-end
- Free pin maps on pinctrl_generic_to_map() failure in the core
helpers
New hardware pin control:
- Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC
(this is for the low power audio, LPASS = Low Power Audio SubSystem
portions)
- Upboard support on top of the Intel pin controller
- Apple T6030 and T6031 support (just compatible strings)
- Samsung Exynos 8855 SoC
- Mediatek MT6858 SoC
- Rockchip RK3308B and RV1106 SoCs
- Airoha EN7523 and AN7563 SoCs
Improvements:
- Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable
- Qualcomm improvements on top of the Qualcomm PDC (power domain
controller) irqchip improvements from tglx:s tree
- Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups
- The NPCM8xx driver has been put into shape fixing many pin and
group definitions
- Some non-urgent Tegra 264 pin assignments are fixed up
- Some non-urgent fixups to Airoha AN7581 and AN7583 registers and
pin assignments, missing features etc"
* tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits)
dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema
pinctrl: meson: sync some modify from A4
pinctrl: meson: a4: Add input enable pin configuration
pinctrl: realtek: rtd1625: remove unused group name spdif_sel
pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13
dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema
Revert "Merge branch 'ib-rsk7204' into devel"
pinctrl: rockchip: Add RV1106 pinctrl support
dt-bindings: pinctrl: rockchip: Add RV1106 compatible
pinctrl: rockchip: Decode drive strength in the get function
pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable
pinctrl: airoha: add support of an7563 SoC
dt-bindings: pinctrl: airoha: add support of an7563 pin controller
pinctrl: airoha: try to find chip scu node by phandle first
pinctrl: airoha: add support of en7523 SoC
dt-bindings: pinctrl: airoha: add support of en7523 pin controller
pinctrl: airoha: an7583: add support for olt pinmux
pinctrl: airoha: an7583: add support for pon_alt pinmux
pinctrl: airoha: an7583: add support for npu_uart pinmux
dt-bindings: pinctrl: airoha: an7583: add missed features
...
Diffstat (limited to 'Documentation/bpf/maps.rst')
| -rw-r--r-- | Documentation/bpf/maps.rst | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/Documentation/bpf/maps.rst b/Documentation/bpf/maps.rst new file mode 100644 index 000000000..6f069f3d6 --- /dev/null +++ b/Documentation/bpf/maps.rst @@ -0,0 +1,82 @@ + +======== +BPF maps +======== + +BPF 'maps' provide generic storage of different types for sharing data between +kernel and user space. There are several storage types available, including +hash, array, bloom filter and radix-tree. Several of the map types exist to +support specific BPF helpers that perform actions based on the map contents. The +maps are accessed from BPF programs via BPF helpers which are documented in the +`man-pages`_ for `bpf-helpers(7)`_. + +BPF maps are accessed from user space via the ``bpf`` syscall, which provides +commands to create maps, lookup elements, update elements and delete elements. +More details of the BPF syscall are available in `ebpf-syscall`_ and in the +`man-pages`_ for `bpf(2)`_. + +Map Types +========= + +.. toctree:: + :maxdepth: 1 + :glob: + + map_* + +Usage Notes +=========== + +.. c:function:: + int bpf(int command, union bpf_attr *attr, u32 size) + +Use the ``bpf()`` system call to perform the operation specified by +``command``. The operation takes parameters provided in ``attr``. The ``size`` +argument is the size of the ``union bpf_attr`` in ``attr``. + +**BPF_MAP_CREATE** + +Create a map with the desired type and attributes in ``attr``: + +.. code-block:: c + + int fd; + union bpf_attr attr = { + .map_type = BPF_MAP_TYPE_ARRAY; /* mandatory */ + .key_size = sizeof(__u32); /* mandatory */ + .value_size = sizeof(__u32); /* mandatory */ + .max_entries = 256; /* mandatory */ + .map_flags = BPF_F_MMAPABLE; + .map_name = "example_array"; + }; + + fd = bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); + +Returns a process-local file descriptor on success, or negative error in case of +failure. The map can be deleted by calling ``close(fd)``. Maps held by open +file descriptors will be deleted automatically when a process exits. + +.. note:: Valid characters for ``map_name`` are ``A-Z``, ``a-z``, ``0-9``, + ``'_'`` and ``'.'``. + +**BPF_MAP_LOOKUP_ELEM** + +Lookup key in a given map using ``attr->map_fd``, ``attr->key``, +``attr->value``. Returns zero and stores found elem into ``attr->value`` on +success, or negative error on failure. + +**BPF_MAP_UPDATE_ELEM** + +Create or update key/value pair in a given map using ``attr->map_fd``, ``attr->key``, +``attr->value``. Returns zero on success or negative error on failure. + +**BPF_MAP_DELETE_ELEM** + +Find and delete element by key in a given map using ``attr->map_fd``, +``attr->key``. Returns zero on success or negative error on failure. + +.. Links: +.. _man-pages: https://www.kernel.org/doc/man-pages/ +.. _bpf(2): https://man7.org/linux/man-pages/man2/bpf.2.html +.. _bpf-helpers(7): https://man7.org/linux/man-pages/man7/bpf-helpers.7.html +.. _ebpf-syscall: https://docs.kernel.org/userspace-api/ebpf/syscall.html |
