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* [RFC PATCH] Series short description
@ 2021-09-23 12:38 Masami Hiramatsu
  2021-09-23 12:40 ` Masami Hiramatsu
  0 siblings, 1 reply; 2+ messages in thread
From: Masami Hiramatsu @ 2021-09-23 12:38 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: Jiri Olsa, Alan Maguire, Masami Hiramatsu, Sven Schnelle, bpf,
	linux-kernel

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@kernel.org>

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [RFC PATCH] Series short description
  2021-09-23 12:38 [RFC PATCH] Series short description Masami Hiramatsu
@ 2021-09-23 12:40 ` Masami Hiramatsu
  0 siblings, 0 replies; 2+ messages in thread
From: Masami Hiramatsu @ 2021-09-23 12:40 UTC (permalink / raw)
  To: Masami Hiramatsu
  Cc: Steven Rostedt, Jiri Olsa, Alan Maguire, Sven Schnelle, bpf,
	linux-kernel

Oops, ignore this. I forgot to update subjects.

On Thu, 23 Sep 2021 21:38:55 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> 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@kernel.org>


-- 
Masami Hiramatsu <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 2+ messages in thread

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