Hi Steve, Here I share my testing patch of the BTF for kprobe events. Currently this only allow user to specify '$$args' for tracing all arguments of the function. This is only avaialbe if - the probe point is on the function entry - the kernel is compiled with BTF (CONFIG_DEBUG_INFO_BTF) - the kernel is enables BPF (CONFIG_BPF_SYSCALL) And Special thanks to Sven! Most of BTF handling part of this patch comes from his patch [1] [1] https://stackframe.org/0001-ftrace-arg-hack.patch What I thought while coding this were; - kernel/bpf/btf.c can be moved under lib/ so that the other subsystems can reuse it, independent from BPF. (Also, this should depends on CONFIG_DEBUG_INFO_BTF) - some more utility functions can be exposed. e.g. I copied btf_type_int() from btf.c - If there are more comments for the BTF APIs, it will be more useful... - Overall, the BTF is easy to understand for who already understand DWARF. Great work! - I think I need 'ptr' and 'bool' types for fetcharg types. Anyway, this is just for testing. I have to add some more cleanup, features and documentations, etc. Thank you, --- Masami Hiramatsu (1): tracing/kprobe: Support $$args for function entry kernel/trace/trace_kprobe.c | 60 ++++++++++++++++++++++++- kernel/trace/trace_probe.c | 105 +++++++++++++++++++++++++++++++++++++++++++ kernel/trace/trace_probe.h | 5 ++ 3 files changed, 168 insertions(+), 2 deletions(-) -- Masami Hiramatsu (Linaro) <mhiramat@xxxxxxxxxx>
