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 8A52F6F061 for ; Mon, 29 Apr 2024 13:18:42 +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=1714396724; cv=none; b=jO00DXBw1ubGaY1NtCczXq9XsVBZ3JKfIfPydDXPxsVETarkTX0GTBd6bhP3+0Z8wAYHxk4rCEHr9BmNAEFRicxFozCLGtNYgL3xL1dpkgSCdcK5TQrVrwnbJK9tIlrwUDxXnHhitM8Cw9SorWZEiB5NH3Epc9xbs+CggbkJuLs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714396724; c=relaxed/simple; bh=IRWWy2IlvuwaKbyTPLqQo5C301oLUpf7IlQGHaPwJ9k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ew/ljzvIxGN8HSqEq5xcEmQYiDb8tznGDj0XMPyoQde1hzB+fc5GeUaJDADF/Otp9ArS0+AzDYrSbkbssr5QIA/vdQwGOrYY/QsOBXsiHtezJQjyepl9BGCXHTdOv3R2LVnAEwu56H24EuFTJBbe2ViKg4ruNgXDwu8hOoXojvs= 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=S8PNixbP; 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="S8PNixbP" 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=ukVgE4qDqlBDH2cqXY2lOwS2mKM9ytx95cPwf5PU+G8=; b=S8PNixbPxQeQKPGe0J0f5+P+68 Zsu5gpzvVxXg0r9x9Zf+DgStHc1+Hd8T9+khCI/LMaLF/8Yyp4fggUmjhx2ZDiQOvGLjpWVnHi6+Q DUOYLTYQ+ixmoLiP5livYM8AOL5tHJBC6ViWzU/GlSaMFndcBcB/8dnvFASoan5QI/G65GHsnfvau KfGwX4PrsgcwKH2PB+CNpElOzjVKX3sZahzu4xzh4ZaGilatFTPjROvPMaVdupzHMC8TxiJwBgr5a YkoBCBg+/W583xm52lGiaeaIaOmQDNgXn1rNi8YVOUPm1GS8ZoeYwA9P7k0emi0dp5DOKyEvZX6g9 VB7GpWhg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:56856) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1s1Qtp-0003E1-1Z; Mon, 29 Apr 2024 14:18:29 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1s1Qtp-0000sO-2Z; Mon, 29 Apr 2024 14:18:29 +0100 Date: Mon, 29 Apr 2024 14:18:28 +0100 From: "Russell King (Oracle)" To: Linus Walleij Cc: Sami Tolvanen , Kees Cook , Nathan Chancellor , Nick Desaulniers , Ard Biesheuvel , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev Subject: Re: [PATCH v5 04/10] ARM: mm: Type-annotate all cache assembly routines Message-ID: References: <20240415-arm32-cfi-v5-0-ff11093eeccc@linaro.org> <20240415-arm32-cfi-v5-4-ff11093eeccc@linaro.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240415-arm32-cfi-v5-4-ff11093eeccc@linaro.org> Sender: Russell King (Oracle) On Mon, Apr 15, 2024 at 03:43:23PM +0200, Linus Walleij wrote: > -ENTRY(fa_flush_user_cache_all) > - /* FALLTHROUGH */ > +SYM_TYPED_FUNC_START(fa_flush_user_cache_all) > + b fa_flush_kern_cache_all > +SYM_FUNC_END(fa_flush_user_cache_all) The thing I don't like about this is that it makes these functions less efficient - the early CPUs do _not_ have branch predictors, and they flush the pipeline on branches, so rather than just dropping rough, this kind of thing introduces pointless multi-cycle delays for functionality just to keep CFI happy. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!