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Date:   Tue, 2 Mar 2021 09:38:37 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Masami Hiramatsu <mhiramat@kernel.org>
Cc:     Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Oleg Nesterov <oleg@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
        "David S . Miller" <davem@davemloft.net>, X86 ML <x86@kernel.org>,
        Andrew Cooper <andrew.cooper3@citrix.com>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [RFC PATCH 1/1] x86/kprobes: Use int3 instead of debug trap for
 single-step
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References: <161460768474.430263.18425867006584111900.stgit@devnote2>
 <161460769556.430263.12936080446789384938.stgit@devnote2>
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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 :-)