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@xxxxxxxxxx/ [3] https://lore.kernel.org/bpf/1657113391-5624-1-git-send-email-alan.maguire@xxxxxxxxxx/ [4] https://lore.kernel.org/bpf/1656942916-13491-1-git-send-email-alan.maguire@xxxxxxxxxx [5] https://lore.kernel.org/bpf/1656667620-18718-1-git-send-email-alan.maguire@xxxxxxxxxx/ [6] https://lore.kernel.org/all/1656089118-577-1-git-send-email-alan.maguire@xxxxxxxxxx/ 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
