From patchwork Mon Dec 9 09:47:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yury Khrustalev X-Patchwork-Id: 13899208 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 2A1F5E7717D for ; Mon, 9 Dec 2024 09:49:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ni769i74TSTMc2HCIR8rv+ryIDdcPChPeu1Bt8O/pdw=; b=c8NPCzJ1rj7y4u5Sg3fHmQPnXp jTpwDzbR+Fq2+kXtdKIvD/fTaJ/azzuVweU5dHWiyuOZQZAnQ92sqvEnqzk1d9vEOpbMf5oPEvXr6 ++7J+rMr8lCLfnRbll0jpbBBljjCiOPnAGmroMSrbVq8bauHRbyK/N3RQ2XIia57Fophz7crn5z5Y wRkkKvmvOz3rZA2WvzTH/nuLhUVVJWBDTqkgmC2XH0VcGHxloInFmHl5/C1Dk1e9zbDUGPKCWBju5 ikXE9+TS7mFUj2+W/bRCQDbovJrumyCFkBiEHOCpGlK1nieCOJ44GQ5RexXp11kbX6+Gr0PGTVvlR PsaOEZWQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tKaOc-000000078vS-0iBK; Mon, 09 Dec 2024 09:49:42 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tKaMf-000000078Qx-314z for linux-arm-kernel@lists.infradead.org; Mon, 09 Dec 2024 09:47:42 +0000 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 25E9A143D; Mon, 9 Dec 2024 01:48:09 -0800 (PST) Received: from udebian.localdomain (unknown [10.1.35.36]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A5B7D3F720; Mon, 9 Dec 2024 01:47:38 -0800 (PST) From: Yury Khrustalev To: linux-arch@vger.kernel.org Cc: Arnd Bergmann , Kevin Brodsky , Joey Gouly , Dave Hansen , Sandipan Das , Michael Ellerman , Catalin Marinas , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, nd@arm.com, Yury Khrustalev Subject: [RESEND v4 1/3] mm/pkey: Add PKEY_UNRESTRICTED macro Date: Mon, 9 Dec 2024 09:47:17 +0000 Message-Id: <20241209094719.2431126-2-yury.khrustalev@arm.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241209094719.2431126-1-yury.khrustalev@arm.com> References: <20241209094719.2431126-1-yury.khrustalev@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241209_014741_796186_1690E261 X-CRM114-Status: UNSURE ( 7.64 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Memory protection keys (pkeys) uapi has two macros for pkeys restrictions: - PKEY_DISABLE_ACCESS 0x1 - PKEY_DISABLE_WRITE 0x2 with implicit literal value of 0x0 that means "unrestricted". Code that works with pkeys has to use this literal value when implying that a pkey imposes no restrictions. This may reduce readability because 0 can be written in various ways (e.g. 0x0 or 0) and also because 0 in the context of pkeys can be mistaken for "no permissions" (akin PROT_NONE) while it actually means "no restrictions". This is important because pkeys are oftentimes used near mprotect() that uses PROT_ macros. This patch adds PKEY_UNRESTRICTED macro defined as 0x0. Signed-off-by: Yury Khrustalev Acked-by: Dave Hansen --- include/uapi/asm-generic/mman-common.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h index 1ea2c4c33b86..ef1c27fa3c57 100644 --- a/include/uapi/asm-generic/mman-common.h +++ b/include/uapi/asm-generic/mman-common.h @@ -85,6 +85,7 @@ /* compatibility flags */ #define MAP_FILE 0 +#define PKEY_UNRESTRICTED 0x0 #define PKEY_DISABLE_ACCESS 0x1 #define PKEY_DISABLE_WRITE 0x2 #define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\