Re: [PATCH v2 1/3] kprobes/x86: use instruction_pointer and instruction_pointer_set

[Masami Hiramatsu]

Hi Jisheng,

On Wed, 21 Aug 2019 02:09:10 +0000
Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx> wrote:

> > > In v2, actually, the arm64 version's kprobe_ftrace_handler() is the same
> > > as x86's, the only difference is comment, e.g
> > >
> > > /* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
> > >
> > > while in arm64
> > >
> > > /* Kprobe handler expects regs->pc = ip + 1 as breakpoint hit */  
> > 
> > As Peter pointed, on arm64, is that really 1 or 4 bytes?
> > This part is heavily depends on the processor software-breakpoint
> > implementation.
> 
> Per my understanding, the "+1" here means "+ one kprobe_opcode_t".

No, that is the size of INT3. It just emulates the software trap on x86.

Thank you,
-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>