Re: [PATCH v2 0/4] openrisc: Add support for KProbes

[Sahil <sahilcdq0@gmail.com>]

On 10/1/26 2:01 AM, Sahil Siddiq wrote:
> Hi,
> 
> Apologies for the delay. This is v2 of the patch series to add KProbe
> support for OpenRISC.
> 
> The series also adds support for Kretprobes (which depends on the rethook
> framework [1]). Kretprobes are fired on function return.
> 
> [...]
> 
> I have also made changes based on the review comments I received for
> v1 [5] including several of Sachiko's comments [6]. I chose not to make
> changes in a few places. I'll send emails as a reply to this thread
> explaining my reasoning inline.
>
> [...]
> 
> Sahil Siddiq (4):
>    openrisc: Add utilities and clean up simulation of instructions
>    openrisc: Add KProbes
>    openrisc: Add unit tests for KProbes on branch instructions
>    openrisc: Add Kretprobes
> 
> [...]> 


Sorry, I forgot to post a summary of the differences between v2 and v1:

Commit #1:
- arch/openrisc/include/asm/cpuinfo.h: Introduce "delay_slot" static key
- arch/openrisc/include/asm/insn-def.h:
   - Use macros instead of union
   - Use better names for macros
   - Use genmask() for masks
- arch/openrisc/kernel/insn.c:
   - Use macros instead of magic values
   - (simulate_pc): Update PC
   - (simulate_branch): Handle rb=r9 in l.jalr simulation
- arch/openrisc/kernel/setup.c: Use "delay slot" static key
- arch/openrisc/kernel/traps.c: Use macros instead of magic values

Commit #2:
- arch/openrisc/include/asm/kprobes.h:
   - (struct prev_kprobe): Add restore_pc
   - (struct kprobe_ctlblk): Move restore_pc from global "struct arch_specific_insn"
- arch/openrisc/kernel/kprobes.c:
   - Use macros instead of magic values
   - Use "get_kernel_nofault" instead of directly dereferencing address
   - (insns_need_simulation): Use "daley slot" static key
   - (arch_prepare_kprobe): Prevent KProbe insertion if instruction in delay slot also requires simulation
   - (save_previous_kprobe): Use "restore_pc"
   - (restore_previous_kprobe): Likewise
   - (post_kprobe_handler): Don't re-enable preemption if KProbe is nested
   - (setup_singlestep): Use "restore_pc"
   - (reenter_kprobe): Return false in case of unrecoverable KProbe
   - (kprobe_singlestep_handler): Enable interrupt in pt_regs->sr
   - (kprobe_fault_handler): Likewise

Commit #3/#4: Introduced in v2 of the series

Thanks,
Sahil