Messages in this thread | | | From | Alan Maguire <> | Subject | [PATCH v6 bpf-next 0/2] bpf: add a ksym BPF iterator | Date | Tue, 12 Jul 2022 13:31:43 +0100 |
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a ksym BPF iterator would be useful as it would allow more flexible interactions with kernel symbols than are currently supported; it could for example create more efficient map representations for lookup, speed up symbol resolution etc.
The idea was initially discussed here [1].
Changes since v5 [2]: - no need to add kallsym_iter to bpf_iter.h as it has existed in kernels for a long time so will by in vmlinux.h for older kernels too, unlike struct bpf_iter__ksym (Yonghong, patch 2)
Changes since v4 [3]:
- add BPF_ITER_RESCHED to improve responsiveness (Hao, patch 1) - remove pr_warn to be consistent with other iterators (Andrii, patch 1) - add definitions to bpf_iter.h to ensure iter tests build on older kernels (Andrii, patch 2)
Changes since v3 [4]:
- use late_initcall() to register iter; means we are both consistent with other iters and can encapsulate all iter-specific code in kallsyms.c in CONFIG_BPF_SYSCALL (Alexei, Yonghong, patch 1).
Changes since v2 [5]:
- set iter->show_value on initialization based on current creds and use it in selftest to determine if we show values (Yonghong, patches 1/2) - inline iter registration into kallsyms_init (Yonghong, patch 1)
Changes since RFC [6]:
- change name of iterator (and associated structures/fields) to "ksym" (Andrii, patches 1, 2) - remove dependency on CONFIG_PROC_FS; it was used for other BPF iterators, and I assumed it was needed because of seq ops but I don't think it is required on digging futher (Andrii, patch 1)
[1] https://lore.kernel.org/all/YjRPZj6Z8vuLeEZo@krava/ [2] https://lore.kernel.org/bpf/1657490998-31468-1-git-send-email-alan.maguire@oracle.com/ [3] https://lore.kernel.org/bpf/1657113391-5624-1-git-send-email-alan.maguire@oracle.com/ [4] https://lore.kernel.org/bpf/1656942916-13491-1-git-send-email-alan.maguire@oracle.com [5] https://lore.kernel.org/bpf/1656667620-18718-1-git-send-email-alan.maguire@oracle.com/ [6] https://lore.kernel.org/all/1656089118-577-1-git-send-email-alan.maguire@oracle.com/
Alan Maguire (2): bpf: add a ksym BPF iterator selftests/bpf: add a ksym iter subtest
kernel/kallsyms.c | 91 +++++++++++++++++++++++ tools/testing/selftests/bpf/prog_tests/bpf_iter.c | 16 ++++ tools/testing/selftests/bpf/progs/bpf_iter.h | 7 ++ tools/testing/selftests/bpf/progs/bpf_iter_ksym.c | 74 ++++++++++++++++++ 4 files changed, 188 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_ksym.c
-- 1.8.3.1
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