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From: "Ahmed S. Darwish" <darwi@linutronix.de>
To: Marcos Del Sol Vives <marcos@orca.pet>
Cc: linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Brian Gerst <brgerst@gmail.com>, Uros Bizjak <ubizjak@gmail.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	David Kaplan <david.kaplan@amd.com>, Kees Cook <kees@kernel.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Oleg Nesterov <oleg@redhat.com>, "Xin Li (Intel)" <xin@zytor.com>,
	Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Subject: Re: [PATCH] x86: add hintable NOPs emulation
Date: Wed, 20 Aug 2025 12:30:41 +0200	[thread overview]
Message-ID: <aKWj0SI1_qmT6dW2@lx-t490> (raw)
In-Reply-To: <aKWfYo8lKmcHE14a@lx-t490>

On Wed, 20 Aug 2025, Ahmed S. Darwish wrote:
>
> Please do:
>
>     #ifdef CONFIG_X86_HNOP_EMU
>     static bool handle_hnop(struct pt_regs *regs)
>     {
> 	// Reference 'hnop_warn' as much as you like
>     }
>     #else
>     static bool handle_hnop(struct pt_regs *regs)
>     {
> 	return false;
>     }
>     # endif
>

And as previously suggested: remove the ugly hnop_warn stuff from
'thread_struct', then you can even just do:

    static bool handle_hnop(struct pt_regs *regs)
    {
	if (!IS_ENABLED(CONFIG_X86_HNOP_EMU))
		return false;

	pr_warn_once("%s[%d] Emulating hintable NOP\n"
		     "This warning will not be repeated; even for other binaries\n"
		     current->comm, task_pid_nr(current));

	...
    }

And everything else will fit quietly in place.

--
Ahmed S. Darwish
Linutronix GmbH

  reply	other threads:[~2025-08-20 10:30 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-20  1:34 [PATCH] x86: add hintable NOPs emulation Marcos Del Sol Vives
2025-08-20  9:07 ` Peter Zijlstra
2025-08-21 12:28   ` David Laight
2025-08-21 12:46     ` Peter Zijlstra
2025-08-21 18:40       ` David Laight
2025-08-21 19:46         ` Marcos Del Sol Vives
2025-08-21 15:11     ` Marcos Del Sol Vives
2025-08-20  9:14 ` Ahmed S. Darwish
2025-08-20  9:33   ` Marcos Del Sol Vives
2025-08-20  9:43     ` Borislav Petkov
2025-08-20  9:51       ` Marcos Del Sol Vives
2025-08-20  9:55         ` Borislav Petkov
2025-08-20 10:01           ` Marcos Del Sol Vives
2025-08-20 10:08             ` Borislav Petkov
2025-08-20 10:21               ` Marcos Del Sol Vives
2025-08-20 10:30                 ` Borislav Petkov
2025-08-21  2:00             ` Kees Cook
2025-08-20 10:11     ` Ahmed S. Darwish
2025-08-20 10:30       ` Ahmed S. Darwish [this message]
2025-08-21  1:43 ` H. Peter Anvin
2025-08-21  9:35   ` Marcos Del Sol Vives
2025-08-21  5:02 ` H. Peter Anvin
2025-08-21 12:26 ` David Laight
2025-08-21 12:48   ` Marcos Del Sol Vives
2025-08-21 12:48 ` Peter Zijlstra
2025-08-21 13:45   ` Marcos Del Sol Vives
2025-08-21 13:59     ` Peter Zijlstra
2025-08-22 22:12   ` H. Peter Anvin

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