From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E1F5DC3DA4A for ; Thu, 1 Aug 2024 11:02:22 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4WZQz14Z7Bz3fVq for ; Thu, 1 Aug 2024 21:02:21 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=dave.martin@arm.com; receiver=lists.ozlabs.org) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 4WZQyb1gRwz30YZ for ; Thu, 1 Aug 2024 21:01:57 +1000 (AEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 570E215A1; Thu, 1 Aug 2024 04:01:52 -0700 (PDT) Received: from e133380.arm.com (e133380.arm.com [10.1.197.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BCA383F5A1; Thu, 1 Aug 2024 04:01:23 -0700 (PDT) Date: Thu, 1 Aug 2024 12:01:18 +0100 From: Dave Martin To: Joey Gouly Subject: Re: [PATCH v4 13/29] arm64: convert protection key into vm_flags and pgprot values Message-ID: References: <20240503130147.1154804-1-joey.gouly@arm.com> <20240503130147.1154804-14-joey.gouly@arm.com> <20240801105502.GA841837@e124191.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240801105502.GA841837@e124191.cambridge.arm.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: szabolcs.nagy@arm.com, catalin.marinas@arm.com, dave.hansen@linux.intel.com, linux-mm@kvack.org, hpa@zytor.com, shuah@kernel.org, maz@kernel.org, x86@kernel.org, christophe.leroy@csgroup.eu, aneesh.kumar@kernel.org, mingo@redhat.com, naveen.n.rao@linux.ibm.com, will@kernel.org, npiggin@gmail.com, broonie@kernel.org, bp@alien8.de, kvmarm@lists.linux.dev, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, oliver.upton@linux.dev, aneesh.kumar@linux.ibm.com, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Aug 01, 2024 at 11:55:02AM +0100, Joey Gouly wrote: > On Thu, Jul 25, 2024 at 04:49:50PM +0100, Dave Martin wrote: > > On Fri, May 03, 2024 at 02:01:31PM +0100, Joey Gouly wrote: > > > Modify arch_calc_vm_prot_bits() and vm_get_page_prot() such that the pkey > > > value is set in the vm_flags and then into the pgprot value. > > > > > > Signed-off-by: Joey Gouly > > > Cc: Catalin Marinas > > > Cc: Will Deacon > > > --- > > > arch/arm64/include/asm/mman.h | 8 +++++++- > > > arch/arm64/mm/mmap.c | 9 +++++++++ > > > 2 files changed, 16 insertions(+), 1 deletion(-) > > > > > > diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h > > > index 5966ee4a6154..ecb2d18dc4d7 100644 > > > --- a/arch/arm64/include/asm/mman.h > > > +++ b/arch/arm64/include/asm/mman.h > > > @@ -7,7 +7,7 @@ > > > #include > > > > > > static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, > > > - unsigned long pkey __always_unused) > > > + unsigned long pkey) > > > { > > > unsigned long ret = 0; > > > > > > @@ -17,6 +17,12 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, > > > if (system_supports_mte() && (prot & PROT_MTE)) > > > ret |= VM_MTE; > > > > > > +#if defined(CONFIG_ARCH_HAS_PKEYS) > > > + ret |= pkey & 0x1 ? VM_PKEY_BIT0 : 0; > > > + ret |= pkey & 0x2 ? VM_PKEY_BIT1 : 0; > > > + ret |= pkey & 0x4 ? VM_PKEY_BIT2 : 0; > > > > Out of interest, is this as bad as it looks or does the compiler turn > > it into a shift and mask? > > Yeah, (gcc 13.2) produces good code here (this is do_mprotect_pkey after removing a lot of branching): > > and w0, w0, #0x7 > orr x1, x1, x0, lsl #32 Neat, good ol' gcc! Cheers ---Dave