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

[Peter Zijlstra]

On Tue, Aug 20, 2019 at 09:02:59AM +0000, Jisheng Zhang 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 */

What's weird; I thought ARM has fixed sized instructions and they are
all 4 bytes? So how does a single byte offset make sense for ARM?