Re: arm64 kprobes patches

[Sandeepa Prabhu <sandeepa.prabhu@linaro.org>]

On 27 February 2014 07:44, Masami Hiramatsu
<masami.hiramatsu.pt@hitachi.com> wrote:
> (2014/02/27 0:02), Sandeepa Prabhu wrote:
>> Hi all,
>>
>> We have uploaded arm64 kprobes latest changes on linaro git which
>> include some fixes for recursive kprobes. These are rebased on top of
>> 3.14-rc3.  Kprobes support can be enabled by enabling
>> "General setup  --->  [*] Kprobes" config option.
>>
>> Git location:  git://git.linaro.org/people/sandeepa.prabhu/linux-aarch64.git
>>  Branch: arm64_kprobes_3.14-rc3
>
> Great! Thank you for working on that!
>
>>
>> Please let us know if you are interested in pulling this branch for
>> systemtap test-suite verification, while we are trying to include
>> systemtap test-suite on our linaro open-embedded platforms.
>>
>> Also, please let us know if there are documentation on howto run full
>> test-suite for systemtap and various criteria  kprobes should meet?
>
> One possible testing is putting kprobes on all functions in the
> kernel by using ftrace interface. (On x86, current kprobes still has
> some problems, and I solved, will send the series later)
OK we will try to verify this with arm64 ftrace patches (from linaro)
which are close to get accepted upstream.
Has your earlier patches (kprobes blacklist related) been queued-up
for upstream? Are you planning generic kprobes API changes ?

>
> You can put kprobes on all kernel functions
>   ----
> #!/bin/sh
> TRACE_DIR=/sys/kernel/debug/tracing/
> grep -iw t /proc/kallsyms | tr -d . | awk 'BEGIN{i=0};{print("p:"$3"_"i, "0x"$1); i++}' | \
> while read l; do echo $l >> $TRACE_DIR/kprobe_events || echo "Failed($?): $l" ; done
>   ----
> Note that this just register *disabled* kprobes on each function.
> To enable each one, you need to write "1" to $TRACE_DIR/events/kprobes/<EVENT>/enable.
> # I recommend you to enable one by one, there still be a performance problem.
>
> Thank you,
> --
> Masami HIRAMATSU
> IT Management Research Dept. Linux Technology Center
> Hitachi, Ltd., Yokohama Research Laboratory
> E-mail: masami.hiramatsu.pt@hitachi.com
>
>