From: Alexandre Chartre <alexandre.chartre@oracle.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: alexandre.chartre@oracle.com, jpoimboe@kernel.org,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] objtool/x86: Fix NOP decode
Date: Thu, 25 Sep 2025 15:05:29 +0200 [thread overview]
Message-ID: <a04049a0-d626-4f42-92ca-0e6d3b847d6a@oracle.com> (raw)
In-Reply-To: <20250925104251.GZ4067720@noisy.programming.kicks-ass.net>
On 9/25/25 12:42, Peter Zijlstra wrote:
> On Thu, Sep 25, 2025 at 12:03:23PM +0200, Peter Zijlstra wrote:
>
>>>>>> case 0x90:
>>>>>> + if (prefix != 0xf3) /* REP NOP := PAUSE */
>>>>>> + insn->type = INSN_NOP;
>>>>>> break;
>
>>> What about 0x49 0x90, which is xchg (XCHG r8,rAX) ?
>
> I've made that:
>
> case 0x90:
> if (rex_b) /* XCHG %r8, %rax */
> break;
>
> if (prefix == 0xf3) /* REP NOP := PAUSE */
> break;
>
> insn->type = INSN_NOP;
> break;
>
>
Sounds good.
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
alex.
next prev parent reply other threads:[~2025-09-25 13:05 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-24 13:45 [PATCH 0/3] objtool: Few x86 decoder updates Peter Zijlstra
2025-09-24 13:45 ` [PATCH 1/3] objtool/x86: Remove 0xea hack Peter Zijlstra
2025-09-25 9:55 ` Alexandre Chartre
2025-10-14 11:47 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2025-09-24 13:45 ` [PATCH 2/3] objtool/x86: Add UDB support Peter Zijlstra
2025-09-25 9:56 ` Alexandre Chartre
2025-10-14 11:47 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2025-09-24 13:45 ` [PATCH 3/3] objtool/x86: Fix NOP decode Peter Zijlstra
2025-09-24 17:34 ` Alexandre Chartre
2025-09-24 18:41 ` Peter Zijlstra
2025-09-25 9:55 ` Alexandre Chartre
2025-09-25 10:03 ` Peter Zijlstra
2025-09-25 10:42 ` Peter Zijlstra
2025-09-25 11:29 ` Andrew Cooper
2025-09-25 12:43 ` Peter Zijlstra
2025-09-25 13:04 ` Alexandre Chartre
2025-09-25 14:11 ` Peter Zijlstra
2025-09-25 13:05 ` Alexandre Chartre [this message]
2025-10-14 11:47 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
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