Re: [PATCH] kprobes for s390 architecture

[Mike Grundy <grundym@us.ibm.com>]

On Wed, Jun 21, 2006 at 06:38:40PM +0200, Martin Schwidefsky wrote:
> You misunderstood me here. I'm not talking about storing the same piece
> of data to memory on each processor. I'm talking about isolating all
> other cpus so that the initiating cpu can store the breakpoint to memory
> without running into the danger that another cpu is trying to execute it
> at the same time. But probably the store should be atomic in regard to
> instruction fetching on the other cpus. It is only two bytes and it
> should be aligned.

So maybe something like this:

void smp_replace_instruction(void *info) {
        struct ins_replace_args *parms;
        parms = (struct ins_replace_args *) info;
        *parms->addr = *parms->insn
}

void __kprobes arch_arm_kprobe(struct kprobe *p)
{
        struct ins_replace_args parms;
        parms.addr = p->addr;
        parms.insn = BREAKPOINT_INSTRUCTION

        preempt_disable();
        smp_call_function(smp_replace_instruction, &parms, 0, 1);
        preempt_enable();
}

Thanks
Mike