From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (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 461681BE23D for ; Thu, 10 Oct 2024 11:55:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728561344; cv=none; b=AKf4CG9foMZj50HvyiXJ9/XqHFRMhpCHgf6p4PZm8wch8ddKaiq00NoJ/t7Br2egjsWPTa3rxfEMLm/z60mELIFwxcOm9/ehtjdr2RPIO9bj/0DG4jED6BjPHhEz3WfCmFCoJZw8CXT++LXM016MbY0C1tdk/1DZ++aza/6u90M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728561344; c=relaxed/simple; bh=9ypUntO+knrZwXW14pBBJWuCGp9e8ARsbAZz6ZyvuJA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VPd96FPP78hv3K+RX8SqhYfSu/KA/Cns4Px30VvsvplnhTLIgFTZmZBgkx6Ac6aAiKhQH7BBKX1Q+SmWbvkSTC+c23mqX05rDHb9JYyEkCxySIARHgQ6yR3rUE3dPfUnOxwUaELRTpd5eAa+CrdEydeXCeNmXzB8kEPxZbdJd+8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=IIe+J1UD; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="IIe+J1UD" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Jgzc/uLviO7J54OVqHpsyMnCk4VTRuOJ3qugkDERST8=; b=IIe+J1UD8SkmQSXtqZvX4LjYxM /0Qpcshk2xUqgwE/jU5u5u9nB6ve8edCv9dFAsxYsM3S+wjJZD+ytsnuWIIx0lbtBnTmW70PGy/Yg dhq8BZm077nnWVQf3Ucm0qP01tA13M774TFjnv4b2zZekyAYVM0HKzbPVdH8lElXZSh8hnskU40yw 9uQ3M1J73m7NhJRRDeKEZf514jrZ1G4Gdmzvj/8Vl9ladGZy6kRKzrMjnP+BJC0ha7VTjxjMn40Sg heqvJhzhOJfoe353S5xm8RhxMf8zN8UUHuNKHPTZDrBkvkarvSNRmIc3ZCCpFgA/4jVj0MqTUgQtZ LqmG04VA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:53502) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1syrlZ-0002IO-0l; Thu, 10 Oct 2024 12:55:36 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.96) (envelope-from ) id 1syrlU-0007HP-2r; Thu, 10 Oct 2024 12:55:32 +0100 Date: Thu, 10 Oct 2024 12:55:32 +0100 From: "Russell King (Oracle)" To: Linus Walleij Cc: Oleg Nesterov , Kees Cook , Andy Lutomirski , Will Drewry , Frederic Weisbecker , "Paul E. McKenney" , Jinjie Ruan , Arnd Bergmann , Ard Biesheuvel , Al Viro , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 00/28] ARM: Switch to generic entry Message-ID: References: <20241010-arm-generic-entry-v1-0-b94f451d087b@linaro.org> 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=us-ascii Content-Disposition: inline In-Reply-To: <20241010-arm-generic-entry-v1-0-b94f451d087b@linaro.org> Sender: Russell King (Oracle) On Thu, Oct 10, 2024 at 01:33:38PM +0200, Linus Walleij wrote: > This patch series converts a slew of ARM assembly into the > corresponding C code, step by step moving the codebase > closer to the expectations of the generic entry code, > and as a last step switches ARM over to the generic > entry code. I haven't looked at the series yet, but I guess we're throwing away all the effort I put in to make stuff like syscalls as fast as possible. So the question is... do we want performance, or do we want generic (and slower) code? It seems insane to me that we spend time micro-optimising things like memcpy, memset, divide routines, but then go and throw away performance that applications actually rely upon, such as syscall performance. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!