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From: Thomas Gleixner <tglx@linutronix.de>
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To: Randy Dunlap <rdunlap@infradead.org>, K Prateek Nayak
 <kprateek.nayak@amd.com>, LKML <linux-kernel@vger.kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, Peter Zijlstra
 <peterz@infradead.org>, "Paul E. McKenney" <paulmck@kernel.org>, Boqun
 Feng <boqun.feng@gmail.com>, Jonathan Corbet <corbet@lwn.net>, Prakash
 Sangappa <prakash.sangappa@oracle.com>, Madadi Vineeth Reddy
 <vineethr@linux.ibm.com>, Steven Rostedt <rostedt@goodmis.org>, Sebastian
 Andrzej Siewior <bigeasy@linutronix.de>, Arnd Bergmann <arnd@arndb.de>,
 linux-arch@vger.kernel.org
Subject: Re: [patch 03/12] rseq: Provide static branch for time slice
 extensions
In-Reply-To: <94f08403-31f5-43ee-871d-5e0ebcfd3b6c@infradead.org>
References: <20250908225709.144709889@linutronix.de>
 <20250908225752.744169647@linutronix.de>
 <0f28cc54-1f84-4f28-bd61-ee9e0b9d0d0c@amd.com>
 <94f08403-31f5-43ee-871d-5e0ebcfd3b6c@infradead.org>
Date: Tue, 09 Sep 2025 14:12:29 +0200
Message-ID: <87v7lrvn82.ffs@tglx>
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On Mon, Sep 08 2025 at 21:11, Randy Dunlap wrote:
> On 9/8/25 8:10 PM, K Prateek Nayak wrote:
>> Hello Thomas,
>> 
>> On 9/9/2025 4:29 AM, Thomas Gleixner wrote:
>>> +#ifdef CONFIG_RSEQ_SLICE_EXTENSION
>>> +DEFINE_STATIC_KEY_TRUE(rseq_slice_extension_key);
>>> +
>>> +static int __init rseq_slice_cmdline(char *str)
>>> +{
>>> +	bool on;
>>> +
>>> +	if (kstrtobool(str, &on))
>>> +		return -EINVAL;
>>> +
>>> +	if (!on)
>>> +		static_branch_disable(&rseq_slice_extension_key);
>>> +	return 0;
>> 
>> I believe this should return "1" signalling that the cmdline was handled
>> correctly to avoid an "Unknown kernel command line parameters" message.
>
> Good catch. I agree.
> Thanks.

It seems I can't get that right ever ....