Re: [RFC PATCH 1/1] x86/kprobes: Use int3 instead of debug trap for single-step

[Peter Zijlstra]

On Mon, Mar 01, 2021 at 11:08:15PM +0900, Masami Hiramatsu wrote:

> +	default:
> +		if ((opcode & 0xf0) == 0x70) {
> +			/* 1 byte conditional jump */
> +			p->ainsn.emulate_op = kprobe_emulate_jcc;
> +			p->ainsn.jcc.type = opcode & 0xf;
> +			p->ainsn.rel32 = *(char *)insn->immediate.bytes;
> +		}
>  	}

Would it make sense to write that as:

	case 0x70 ... 0x7f:
		/* 1 byte conditional jump */
		p->ainsn.emulate_op = kprobe_emulate_jcc;
		p->ainsn.jcc.type = opcode & 0xf;
		p->ainsn.rel32 = *(char *)insn->immediate.bytes;
		break;

instead? Preferably right before the 0x0f case :-)