From patchwork Mon Feb 3 10:18:28 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Brodsky X-Patchwork-Id: 13957226 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 4C217C02192 for ; Mon, 3 Feb 2025 10:26:40 +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=95g1WdvJ15ICDChHvnYK8BK/i5y+G7j4b0SSgWLyqq8=; b=1NDYCHdcthloy0kek9qEdeFj1n 0llMDF78z3Svwu6HmnRZTXHYg/D2l8P4emG9H5GGzfSUKMI7rt1OyE714vFCVvv55vyGJBUL8DbwW Au+FGY/2FXIaW8b2ULSxQ5h6l6mwudcb4qD3fOhsws6G6Vg5UN0Rmh/5wWjnero8Ow7YtPiGZoH7p /o9mV0c2FvPw6KRVKkzLbuNeC6++kOx0wz2eZFQKDR6iLAuM98TlZyAHbcmETssXlBfsUG/DCHJHs zh0WbcB3RnAgvRQqf5bKFgk8WFm84lS8MngFpsHgcHkUw0sUEC36XiWG1p4/FxWe9MbMMGnnL9sgT OBTFaJ9A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tetev-0000000F7DE-1uah; Mon, 03 Feb 2025 10:26:29 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tetYf-0000000F60L-1BnC for linux-arm-kernel@bombadil.infradead.org; Mon, 03 Feb 2025 10:20:01 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=95g1WdvJ15ICDChHvnYK8BK/i5y+G7j4b0SSgWLyqq8=; b=beDtAxB67b1im2iDRBmwu/m1zc W8ULehtbee00RIRSOP8nsYRkPxylyZSLX6tK4nsxUSF1DrAmqHtCZKE4ntPMW4QEGemkBoP6HMxGa vQUMWi2os8URnPJ66MF9sBWBm3Ys3q4/BT/q5RmvZEU8qcKetW/Zol6qp17ZghngFk7Q3O0UGXOMz zB/Tq+X0SY8J7Afo6SP4zX+sHMPp9j8HV9XWIQ3oZ1+6NOsRRCWzSL+yRHSJRwId2vJgN1omzQn01 /wwta+8FS2vkTfEhNwIBtdIFV9YUoClwKcW4SE29NQK45fGeolN7NIDTjYBLOxlPQvRz2bJw+RtWv Iact7tQg==; Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tetYc-0000000G3RO-0MtD for linux-arm-kernel@lists.infradead.org; Mon, 03 Feb 2025 10:20:00 +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 BF4FA11FB; Mon, 3 Feb 2025 02:20:21 -0800 (PST) Received: from e123572-lin.arm.com (e123572-lin.cambridge.arm.com [10.1.194.54]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CD9ED3F63F; Mon, 3 Feb 2025 02:19:53 -0800 (PST) From: Kevin Brodsky To: linux-hardening@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Kevin Brodsky , Andrew Morton , Mark Brown , Catalin Marinas , Dave Hansen , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Andy Lutomirski , Marc Zyngier , Peter Zijlstra , Pierre Langlois , Quentin Perret , "Mike Rapoport (IBM)" , Ryan Roberts , Thomas Gleixner , Will Deacon , Matthew Wilcox , Qi Zheng , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org Subject: [RFC PATCH v3 04/15] arm64: Introduce por_set_pkey_perms() helper Date: Mon, 3 Feb 2025 10:18:28 +0000 Message-ID: <20250203101839.1223008-5-kevin.brodsky@arm.com> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20250203101839.1223008-1-kevin.brodsky@arm.com> References: <20250203101839.1223008-1-kevin.brodsky@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250203_101958_554310_0AAB6763 X-CRM114-Status: GOOD ( 13.80 ) 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 Introduce a helper that sets the permissions of a given pkey (POIndex) in the POR_ELx format, and make use of it in arch_set_user_pkey_access(). Also ensure that is included in asm/por.h to provide the POE_* definitions. Signed-off-by: Kevin Brodsky --- arch/arm64/include/asm/por.h | 9 +++++++++ arch/arm64/mm/mmu.c | 28 ++++++++++------------------ 2 files changed, 19 insertions(+), 18 deletions(-) diff --git a/arch/arm64/include/asm/por.h b/arch/arm64/include/asm/por.h index e06e9f473675..7f0d73980cce 100644 --- a/arch/arm64/include/asm/por.h +++ b/arch/arm64/include/asm/por.h @@ -6,6 +6,8 @@ #ifndef _ASM_ARM64_POR_H #define _ASM_ARM64_POR_H +#include + #define POR_BITS_PER_PKEY 4 #define POR_ELx_IDX(por_elx, idx) (((por_elx) >> ((idx) * POR_BITS_PER_PKEY)) & 0xf) @@ -30,4 +32,11 @@ static inline bool por_elx_allows_exec(u64 por, u8 pkey) return perm & POE_X; } +static inline u64 por_set_pkey_perms(u64 por, u8 pkey, u64 perms) +{ + u64 shift = pkey * POR_BITS_PER_PKEY; + + return (por & ~(POE_MASK << shift)) | (perms << shift); +} + #endif /* _ASM_ARM64_POR_H */ diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index b4df5bc5b1b8..9547183d86cf 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1555,9 +1555,8 @@ void __cpu_replace_ttbr1(pgd_t *pgdp, bool cnp) #ifdef CONFIG_ARCH_HAS_PKEYS int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) { - u64 new_por = POE_RXW; - u64 old_por; - u64 pkey_shift; + u64 new_perms; + u64 por; if (!system_supports_poe()) return -ENOSPC; @@ -1571,26 +1570,19 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long i return -EINVAL; /* Set the bits we need in POR: */ - new_por = POE_RXW; + new_perms = POE_RXW; if (init_val & PKEY_DISABLE_WRITE) - new_por &= ~POE_W; + new_perms &= ~POE_W; if (init_val & PKEY_DISABLE_ACCESS) - new_por &= ~POE_RW; + new_perms &= ~POE_RW; if (init_val & PKEY_DISABLE_READ) - new_por &= ~POE_R; + new_perms &= ~POE_R; if (init_val & PKEY_DISABLE_EXECUTE) - new_por &= ~POE_X; + new_perms &= ~POE_X; - /* Shift the bits in to the correct place in POR for pkey: */ - pkey_shift = pkey * POR_BITS_PER_PKEY; - new_por <<= pkey_shift; - - /* Get old POR and mask off any old bits in place: */ - old_por = read_sysreg_s(SYS_POR_EL0); - old_por &= ~(POE_MASK << pkey_shift); - - /* Write old part along with new part: */ - write_sysreg_s(old_por | new_por, SYS_POR_EL0); + por = read_sysreg_s(SYS_POR_EL0); + por = por_set_pkey_perms(por, pkey, new_perms); + write_sysreg_s(por, SYS_POR_EL0); return 0; }