From: Alexandre Chartre <alexandre.chartre@oracle.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: alexandre.chartre@oracle.com, linux-kernel@vger.kernel.org,
mingo@kernel.org, jpoimboe@kernel.org
Subject: Re: [RFC PATCH v2 00/17] objtool: Function validation tracing
Date: Wed, 24 Sep 2025 12:52:35 +0200 [thread overview]
Message-ID: <90abf24a-326a-4215-8e13-2e1a2e3194ea@oracle.com> (raw)
In-Reply-To: <20250924101038.GZ4068168@noisy.programming.kicks-ass.net>
On 9/24/25 12:10, Peter Zijlstra wrote:
> On Wed, Sep 24, 2025 at 12:08:47PM +0200, Peter Zijlstra wrote:
>> On Wed, Sep 24, 2025 at 09:42:06AM +0200, Peter Zijlstra wrote:
>>
>>>>> d051: perf_get_x86_pmu_capability+0x51 | xchg %ax,%ax
>>
>> That libopcode is 'funny', isn't that typically spelled "nop" ?
>
> Ooh, I see, it is "osp nop" and yeah binutils also seems to do that as
> "xchg %ax,%ax".
Yes, "xchg %ax,%ax" is NOP2 (opcodes: 0x66 0x90), "nop" is NOP1 (0x90).
That's one more improvement we can do: identify NOP instructions and
display them as NOP<n>
alex.
next prev parent reply other threads:[~2025-09-24 10:52 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-19 14:56 Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 01/17] objtool: Move disassembly functions to a separated file Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 02/17] objtool: Create disassembly context Alexandre Chartre
2025-09-23 22:23 ` Josh Poimboeuf
2025-06-19 14:56 ` [RFC PATCH v2 03/17] objtool: Disassemble code with libopcodes instead of running objdump Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 04/17] tool build: Remove annoying newline in build output Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 05/17] objtool: Print symbol during disassembly Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 06/17] objtool: Improve offstr() output Alexandre Chartre
2025-09-23 22:23 ` Josh Poimboeuf
2025-06-19 14:56 ` [RFC PATCH v2 07/17] objtool: Store instruction disassembly result Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 08/17] objtool: Disassemble instruction on warning or backtrace Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 09/17] objtool: Extract code to validate instruction from the validate branch loop Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 10/17] objtool: Record symbol name max length Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 11/17] objtool: Add option to trace function validation Alexandre Chartre
2025-09-23 22:25 ` Josh Poimboeuf
2025-06-19 14:56 ` [RFC PATCH v2 12/17] objtool: Trace instruction state changes during " Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 13/17] objtool: Improve register reporting " Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 14/17] objtool: Improve tracing of alternative instructions Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 15/17] objtool: Do not validate IBT for .return_sites and .call_sites Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 16/17] objtool: Add the --disas=<function-pattern> action Alexandre Chartre
2025-06-19 14:56 ` [RFC PATCH v2 17/17] objtool: Disassemble all alternatives when using --disas Alexandre Chartre
2025-09-23 22:33 ` [RFC PATCH v2 00/17] objtool: Function validation tracing Josh Poimboeuf
2025-09-24 9:25 ` Alexandre Chartre
2025-09-24 7:36 ` Peter Zijlstra
2025-09-24 7:42 ` Peter Zijlstra
2025-09-24 10:08 ` Peter Zijlstra
2025-09-24 10:10 ` Peter Zijlstra
2025-09-24 10:52 ` Alexandre Chartre [this message]
2025-09-24 10:58 ` Peter Zijlstra
2025-09-24 11:45 ` Peter Zijlstra
2025-09-24 11:57 ` Alexandre Chartre
2025-09-24 9:17 ` Peter Zijlstra
2025-09-24 9:50 ` Alexandre Chartre
2025-09-24 9:57 ` Peter Zijlstra
2025-09-24 9:37 ` Alexandre Chartre
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