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SubjectRe: [PATCH RFC v2 0/6] ARM64: Add kernel probes(Kprobes) support
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On 18 October 2013 14:02, Masami Hiramatsu
<masami.hiramatsu.pt@hitachi.com> wrote:
> (2013/10/17 20:17), Sandeepa Prabhu wrote:
>> This patchset adds support for kernel probes(kprobes), jump probes(jprobes)
>> and return probes(kretprobes) support for ARM64.
>>
>> Kprobes mechanism make use of software breakpoint and single stepping
>> support available in ARM v8 kernel.
>>
>
> Thank you! This looks much better for me now. ;)
>
>> This patchset make use of (and dependant upon) dynamic kernel patching
>> feature published in patch series: https://lkml.org/lkml/2013/10/15/891
>>
>> changes: v1 -> v2
>> 1. Implemented review comments on v1
>> 2. Debug montior hooks implementation is changed to use rwlocks
>> instead of rcu and spinlock.
>
> Eventually, we'd better reconsider using rcu there, or prohibit probing
> readlock related functions. For the first step, this will be good.
Okay, can be done while optimizing kprobes right, since systemtap/ktap
is yet to be verified on this patchset,
so can expect more scope for optimizing the paths for performance.
>
>> 3. Enabled recursing in kprobes handler for kprobes re-enter support.
>> 4. Re-split the patchset to seperate single-stepping, simulation and
>> kretprobes features.
>> 5. instruction simulation is made independent of 'struct kprobes'
>> 6. Added 'Linaro Copyright' statements in new added files.
>> 7. Used arm64 instead of aarch64 in file names and comments.
>>
>> Tested on ARM v8 fast model with sample modules from: samples/kprobes/
>>
>> Sandeepa Prabhu (6):
>> arm64: support single-step and breakpoint handler hooks
>> arm64: Kprobes with single stepping support
>> arm64: Kprobes instruction simulation support
>> arm64: Add kernel return probes support(kretprobes)
>> arm64: Enable kprobes support for arm64 platform
>> kprobes: Add cases for arm and arm64 in sample module
>>
>> arch/arm64/Kconfig | 2 +
>> arch/arm64/configs/defconfig | 20 +-
>> arch/arm64/include/asm/debug-monitors.h | 21 +
>> arch/arm64/include/asm/kprobes.h | 60 +++
>> arch/arm64/include/asm/probes.h | 50 +++
>> arch/arm64/include/asm/ptrace.h | 6 +
>> arch/arm64/kernel/Makefile | 2 +
>> arch/arm64/kernel/condn-helpers.c | 120 ++++++
>> arch/arm64/kernel/debug-monitors.c | 86 +++-
>> arch/arm64/kernel/entry.S | 2 +
>
>
>> arch/arm64/kernel/kprobes-arm64.c | 313 +++++++++++++++
>> arch/arm64/kernel/kprobes-arm64.h | 30 ++
>
> One comment, this name looks a bit wired. Since it seems that these are
> for instruction decoding, can we merge it with probe-decode.h and
> rename it as probe-decode.{h,c}? When we implement uprobes, we still
> can expand it (add the decoding table for uprobes in the probe-decode.c).
probe-decode.c looks fine, as uprobes decode table can be added in
same place. -TODO for the next version.

>
>> arch/arm64/kernel/kprobes.c | 682 ++++++++++++++++++++++++++++++++
>> arch/arm64/kernel/kprobes.h | 30 ++
>> arch/arm64/kernel/probes-decode.h | 110 ++++++
>> arch/arm64/kernel/simulate-insn.c | 184 +++++++++
>> arch/arm64/kernel/simulate-insn.h | 33 ++
>> arch/arm64/kernel/vmlinux.lds.S | 1 +
>> samples/kprobes/kprobe_example.c | 16 +
>> 19 files changed, 1756 insertions(+), 12 deletions(-)
>
> BTW, is there any public git repository which has this series?
Yes, uploaded on linaro git:
https://git.linaro.org/gitweb?p=people/sandeepa.prabhu/linux-aarch64.git;a=shortlog;h=refs/heads/arm64-kprobes-v2

>
> Thank you again!
>
> --
> Masami HIRAMATSU
> IT Management Research Dept. Linux Technology Center
> Hitachi, Ltd., Yokohama Research Laboratory
> E-mail: masami.hiramatsu.pt@hitachi.com
>
>


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