From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F32E5285C82 for ; Tue, 2 Sep 2025 18:36:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756838220; cv=none; b=obZxCQGnzqRaTMP8zuzBq9idojwM1Zkh4hcYLNn4vszsCHSZHBnuzWuUb8yP6Q2vzhmWJG9a7MCLAJUMCMr2+sj+hwguzGK6O1L8sJAtJ4/wSJz4xyyhRPsxr4+xuhM3hS5yn0Tynu/XPFS/EHhY+ZEtEnwJqnLXxI8K0ktmjPI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756838220; c=relaxed/simple; bh=rCK0XmdfirdTjBzYP6rjoHXY9+FRkmLuEnUZBr+vqXk=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=BbKgv1c5nlHa/hzpRdj2XI7qgIVEosKH0mOHd3iwgew3is7zvIY3OJrCBm9qLFORu0Gb7TrO7ttN2+B3Tt4eQ8Lc0TxtxPK0MK53RQ01scVdIzTxf9KEylhQSwa4qkSDzQ6GRBLQmUNm08Wo7w4AD8J/7whSvNvOYSl7JxI2/LY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=iqmchAm8; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=PRT4StSM; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="iqmchAm8"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="PRT4StSM" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1756838216; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rCK0XmdfirdTjBzYP6rjoHXY9+FRkmLuEnUZBr+vqXk=; b=iqmchAm8KnDwQOOjAfyHMSNgR2/bqyjy9UVQaKrwBHG81Wz8Fmf9y3xDsJvAPExOtZ96Pr +leETdBLFiRhoc8uKOHJqFfwODJ9mc9i62FtiwJnuo2cxOrpNi1XO8QBJ8fRiI2FalXyCT sxLWWnzSxMW2nuL3OgP/6tqa/okk53SM3bN9rJx0XPPq1mYkgVar9itt1x1dub+MNhI9cW 6cWowCzXktnYuy93yJh1vQYXuCalNGyjZoFhoC7QvlaTJTZ05zRX9e4IAyhr5ZlZHoUzYA oV2uZbGnvZnd+7xzGrTHCsKPVoA4wpVPy1yZXx6WnUSitHPXjb8+fxiX31V6Xw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1756838216; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rCK0XmdfirdTjBzYP6rjoHXY9+FRkmLuEnUZBr+vqXk=; b=PRT4StSMELZKwpYRKmGWd12NxutTM7OL4rcGtSEJMUZYUAdmbLwZDRiJ5t5xATKPP5NKD3 OO0jzBFuv9Dlq3Ag== To: Mathieu Desnoyers , LKML Cc: Jens Axboe , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Paolo Bonzini , Sean Christopherson , Wei Liu , Dexuan Cui , x86@kernel.org, Arnd Bergmann , Heiko Carstens , Christian Borntraeger , Sven Schnelle , Huacai Chen , Paul Walmsley , Palmer Dabbelt Subject: Re: [patch V2 28/37] rseq: Switch to fast path processing on exit to user In-Reply-To: <02e74cef-f2fe-4590-8921-ef4df2b24786@efficios.com> References: <20250823161326.635281786@linutronix.de> <20250823161655.063205235@linutronix.de> <02e74cef-f2fe-4590-8921-ef4df2b24786@efficios.com> Date: Tue, 02 Sep 2025 20:36:55 +0200 Message-ID: <87iki0zooo.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: base64 T24gV2VkLCBBdWcgMjcgMjAyNSBhdCAwOTo0NSwgTWF0aGlldSBEZXNub3llcnMgd3JvdGU6DQo+ IE9uIDIwMjUtMDgtMjYgMTE6NDAsIE1hdGhpZXUgRGVzbm95ZXJzIHdyb3RlOg0KPj4+IMKgwqAg UlNFUSBzZWxmdGVzdHPCoMKgwqDCoMKgIEJlZm9yZcKgwqDCoMKgwqDCoMKgwqDCoCBBZnRlcsKg wqDCoMKgwqDCoMKgwqDCoMKgwqDCoMKgIFJlZHVjdGlvbg0KPj4+DQo+Pj4gwqDCoCBleGl0IHRv IHVzZXI6wqDCoMKgwqDCoMKgIDM4NjI4MTc3OMKgwqDCoMKgwqDCoMKgwqDCoCAzODczNzM3NTAN Cj4+PiDCoMKgIHNpZ25hbCBjaGVja3M6wqDCoMKgwqDCoMKgIDM1NjYxMjAzwqDCoMKgwqDCoMKg wqDCoMKgwqDCoMKgwqDCoMKgwqDCoCAwwqDCoMKgwqDCoMKgwqDCoMKgwqAgMTAwJQ0KPj4+IMKg wqAgc2xvd3BhdGggcnVuczrCoMKgwqDCoMKgIDE0MDU0MjM5NiAzNi4zOCXCoMKgwqDCoMKgwqDC oMKgwqDCoMKgIDEwMMKgIDAuMDAlwqDCoMKgIDEwMCUNCj4+PiDCoMKgIGZhc3RwYXRoIHJ1bnM6 wqDCoMKgwqDCoMKgwqDCoMKgwqDCoMKgwqDCoMKgwqDCoMKgwqDCoMKgwqDCoMKgIDk1MDk3ODnC oCAyLjUxJcKgwqDCoMKgIE4vQQ0KPj4+IMKgwqAgaWQgdXBkYXRlczrCoMKgwqDCoMKgwqDCoMKg IDE3NjIwMzU5OSA0NS42MiXCoMKgwqDCoMKgwqDCoCA5MDg3OTk0wqAgMi4zNSXCoMKgwqDCoCA5 NSUNCj4+PiDCoMKgIGNzIGNoZWNrczrCoMKgwqDCoMKgwqDCoMKgwqAgMTc1NTg3ODU2IDQ1LjQ2 JcKgwqDCoMKgwqDCoMKgIDQ3MjgzOTTCoCAxLjIyJcKgwqDCoMKgIDk4JQ0KPj4+IMKgwqDCoMKg IGNzIGNsZWFyZWQ6wqDCoMKgwqDCoMKgIDE3MjM1OTU0NMKgwqAgOTguMTYlwqDCoMKgIDEzMTkz MDfCoMKgIDI3LjkwJcKgwqAgOTklDQo+Pj4gwqDCoMKgwqAgY3MgZml4dXA6wqDCoMKgwqDCoMKg wqDCoMKgwqAgMzIyODMxMsKgwqDCoCAxLjg0JcKgwqDCoCAzNDA5MDg3wqDCoCA3Mi4xMCUNCj4N Cj4gQnkgdGhlIHdheSwgeW91IHNob3VsZCByZWFsbHkgbm90IGJlIHVzaW5nIHRoZSBlbnRpcmUg cnNlcSBzZWxmdGVzdHMNCj4gYXMgYSByZXByZXNlbnRhdGl2ZSB3b3JrbG9hZCBmb3IgcHJvZmls aW5nIHRoZSBrZXJuZWwgcnNlcSBpbXBsZW1lbnRhdGlvbi4NCj4NCj4gVGhvc2Ugc2VsZnRlc3Rz IGluY2x1ZGUgImxvb3AgaW5qZWN0aW9uIiwgInlpZWxkIGluamVjdGlvbiIsICJraWxsDQo+IGlu amVjdGlvbiIgYW5kICJzbGVlcCBpbmplY3Rpb24iIHdpdGhpbiB0aGUgcmVsZXZhbnQgdXNlcnNw YWNlIGNvZGUNCj4gcGF0aHMsIHdoaWNoIHJlYWxseSBpbmNyZWFzZSB0aGUgbGlrZWxpaG9vZCBv ZiBoaXR0aW5nIHN0dWZmIGxpa2UNCj4gImNzIGZpeHVwIiBjb21wYXJlZCB0byBhbnl0aGluZyB0 aGF0IGNvbWVzIGNsb3NlIHRvIGEgcmVhbGlzdGljDQo+IHVzZS1jYXNlLiBUaGlzIGlzIHJlYWxs eSB1c2VmdWwgZm9yIHRlc3RpbmcgY29ycmVjdG5lc3MsIGJ1dCBub3QNCj4gZm9yIHByb2ZpbGlu Zy4gRm9yIGluc3RhbmNlLCB0aGUgImxvb3AgaW5qZWN0aW9uIiBpbnRyb2R1Y2VzIGJ1c3kNCj4g bG9vcHMgd2l0aGluIHJzZXEgY3JpdGljYWwgc2VjdGlvbnMgdG8gc2lnbmlmaWNhbnRseSBpbmNy ZWFzZSB0aGUNCj4gbGlrZWxpaG9vZCBvZiBoaXR0aW5nIGEgY3MgZml4dXAuDQo+DQo+IFRob3Nl IHNwZWNpZmljIHNlbGZ0ZXN0cyBhcmUgcmVhbGx5IGp1c3QgInN0cmVzcy10ZXN0cyIgdGhhdCBk b24ndA0KPiByZXByZXNlbnQgYW55IHJlbGV2YW50IHdvcmtsb2FkLg0KDQpUcnVlLCB0aGV5IHN0 aWxsIHRlbGwgaG93IG11Y2ggdXNlbGVzcyB3b3JrIHRoZSBrZXJuZWwgd2FzIGRvaW5nLCBubz8N Cg0K