Re: [PATCH v10 0/4] Add kprobe and kretprobe support for LoongArch

[Huacai Chen]

Hi, Masami,

This series looks good to me now, but I'm not familiar with kprobes.
So, if you have any comments, please let me know.

And Jeff,

As we all know, you are an expert in this domain, so could you please
help me to test this series?

If there are no objections, I plan to merge this series in a few days.
But since the next merge window will be open soon, if there are any
problems, I will revert the patches to wait for the next cycle.

Thanks,
Huacai

On Fri, Dec 9, 2022 at 4:53 PM Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> wrote:
>
> v10:
>   -- Remove sign_extend() based on the latest code
>   -- Rename insns_are_not_supported() to insns_not_supported()
>   -- Rename insns_are_not_simulated() to insns_not_simulated()
>   -- Set KPROBE_HIT_SSDONE if cur->post_handler is not NULL
>   -- Enable preemption for KPROBE_REENTER in kprobe_fault_handler()
>
> v9:
>   -- Rename sign_extended() to sign_extend()
>   -- Modify kprobe_fault_handler() to handle all of kprobe_status
>
> v8:
>   -- Put "regs->csr_prmd &= ~CSR_PRMD_PIE;" ahead to save one line
>   -- Add code comment of preempt_disable()
>   -- Put kprobe_page_fault() in __do_page_fault()
>   -- Modify the check condition of break insn in kprobe_breakpoint_handler()
>
> v7:
>   -- Remove stop_machine_cpuslocked() related code
>
> v6:
>   -- Add a new patch to redefine larch_insn_patch_text() with
>      stop_machine_cpuslocked()
>   -- Modify kprobe_breakpoint_handler() to consider the original
>      insn is break and return the correct value
>   -- Modify do_bp() to refresh bcode when original insn is break
>
> v5:
>   -- Rebase on the latest code
>   -- Use stop_machine_cpuslocked() to modify insn to avoid CPU race
>
> v4:
>   -- Remove kprobe_exceptions_notify() in kprobes.c
>   -- Call kprobe_breakpoint_handler() and kprobe_singlestep_handler()
>      in do_bp()
>
> v3:
>   -- Rebase on the latest code
>   -- Check the alignment of PC in simu_branch() and simu_pc()
>   -- Add ibar in flush_insn_slot()
>   -- Rename kprobe_{pre,post}_handler() to {post_}kprobe_handler
>   -- Add preempt_disable() and preempt_enable_no_resched()
>   -- Remove r0 save/restore and do some minor changes
>      in kprobes_trampoline.S
>   -- Do not enable CONFIG_KPROBES by default
>
> v2:
>   -- Split simu_branch() and simu_pc() into a single patch
>   -- Call kprobe_page_fault() in do_page_fault()
>   -- Add kprobes_trampoline.S for kretprobe
>
> Tiezhu Yang (4):
>   LoongArch: Simulate branch and PC instructions
>   LoongArch: Add kprobe support
>   LoongArch: Add kretprobe support
>   samples/kprobes: Add LoongArch support
>
>  arch/loongarch/Kconfig                     |   2 +
>  arch/loongarch/include/asm/inst.h          |  20 ++
>  arch/loongarch/include/asm/kprobes.h       |  59 +++++
>  arch/loongarch/include/asm/ptrace.h        |   1 +
>  arch/loongarch/kernel/Makefile             |   2 +
>  arch/loongarch/kernel/inst.c               | 123 ++++++++++
>  arch/loongarch/kernel/kprobes.c            | 364 +++++++++++++++++++++++++++++
>  arch/loongarch/kernel/kprobes_trampoline.S |  96 ++++++++
>  arch/loongarch/kernel/traps.c              |  13 +-
>  arch/loongarch/mm/fault.c                  |   3 +
>  samples/kprobes/kprobe_example.c           |   8 +
>  11 files changed, 687 insertions(+), 4 deletions(-)
>  create mode 100644 arch/loongarch/include/asm/kprobes.h
>  create mode 100644 arch/loongarch/kernel/kprobes.c
>  create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S
>
> --
> 2.1.0
>