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 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 3FFF5C5DF84 for ; Tue, 18 Aug 2026 14:11:53 +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:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ooj4RdTct5lgHaX1GvqaQ3GTFEQHRRvtsBE0okBw5Bs=; b=r5eBwRqH+LkWVdQXahFyzv+sIX /X6euZhPtJjk6eT28cxMFDRjEm5cX5qoKk3ar1P1wWUr5yBx+90TxgluHb1lG356wQwIL6zgnqitO C19k38/URiKj/XL1/ImxIdiw1hkgZe1NiJelXu4jgHykXbqaPCLPpfFEld94uWH35wFsityeIjvb3 +rzmuGgNWTs4N6KxijAfWOICkJ8cjjHUMTUrxFgWcVomGyBXKkyp9NsEkU3f/gty2RWKOLNmu/AJk 5VMK3b94GARdRc9P+FLYClyfaIKyn0rQ1uG7CLpDu7qgwwJoZbKTN77lL6ZeFa5X2TSnfrpGz5EuQ /o7VYAwg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wwKXa-000000086eZ-1jVK; Tue, 18 Aug 2026 14:11:46 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wwKXX-000000086dI-3Ur7 for linux-arm-kernel@lists.infradead.org; Tue, 18 Aug 2026 14:11:45 +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 1D35219F6; Tue, 18 Aug 2026 07:11:38 -0700 (PDT) Received: from localhost.localdomain (e123572-lin.cambridge.arm.com [10.2.208.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5D6083F85F; Tue, 18 Aug 2026 07:11:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1787062302; bh=BkjNRdlehpq/qqZwQhBLzY19lD555G+nB+rRbzspEEE=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=WXekD//Fmvb8C1WyhB1190zPRpkkuswNYtmwwoMeNS+olFxji+e80KDeIztBkSSqE 1N8MXkQ+SkSeSh4MWEyuEkArYRfTujxs6s7NTROKtDpdvnWDviu8lnOK7SFAEZjvZa +iqm+CakJdybHTz5fi65HVUhf1uIj56pfWjDYRoA= From: Kevin Brodsky Date: Tue, 18 Aug 2026 15:08:46 +0100 Subject: [PATCH RFC v9 04/25] arm64: Introduce por_elx_set_pkey_perms() helper MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260818-kpkeys-v9-4-743ad31b2c8f@arm.com> References: <20260818-kpkeys-v9-0-743ad31b2c8f@arm.com> In-Reply-To: <20260818-kpkeys-v9-0-743ad31b2c8f@arm.com> To: linux-hardening@vger.kernel.org Cc: Kevin Brodsky , Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linu Cherian , Linus Walleij , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , =?utf-8?q?Pierre-Cl=C3=A9ment_Tosi?= , Quentin Perret , Rick Edgecombe , Ryan Roberts , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Ira Weiny , Lorenzo Stoakes , Thomas Gleixner X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1787062276; l=2582; i=kevin.brodsky@arm.com; s=20260427; h=from:subject:message-id; bh=BkjNRdlehpq/qqZwQhBLzY19lD555G+nB+rRbzspEEE=; b=4ZTyW5TcfHxhyckVVjluqnadzTDAbx78zgNQa3gNuWY+CA+irOo4uc0URWKL6zTzAj8ERPxz5 gARLFho9C3ZB33hSphiUVjYeAThs20KMb6VCEKJUc25+Dwhztu0cOIg X-Developer-Key: i=kevin.brodsky@arm.com; a=ed25519; pk=N2QG+eJKrvkNovwhhwJhnJ4+ScVfsGCHldmqLfcMTFs= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260818_071143_953521_F873C62A X-CRM114-Status: GOOD ( 14.05 ) 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(). new_por now represents the permissions of a single pkey, so rename it to new_perms and change its type accordingly. Reviewed-by: David Hildenbrand (Arm) Signed-off-by: Kevin Brodsky --- arch/arm64/include/asm/por.h | 7 +++++++ arch/arm64/mm/mmu.c | 26 ++++++++++---------------- 2 files changed, 17 insertions(+), 16 deletions(-) diff --git a/arch/arm64/include/asm/por.h b/arch/arm64/include/asm/por.h index d913d5b529e4..19b3dd1d43a0 100644 --- a/arch/arm64/include/asm/por.h +++ b/arch/arm64/include/asm/por.h @@ -31,4 +31,11 @@ static inline bool por_elx_allows_exec(u64 por, u8 pkey) return perm & POE_X; } +static inline u64 por_elx_set_pkey_perms(u64 por, u8 pkey, u8 perms) +{ + u64 shift = POR_ELx_PERM_SHIFT(pkey); + + return (por & ~(POE_MASK << shift)) | ((u64)perms << shift); +} + #endif /* _ASM_ARM64_POR_H */ diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index d4de88770ecf..767478d9e84b 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -2305,8 +2305,8 @@ void __cpu_replace_ttbr1(pgd_t *pgdp, bool cnp) #ifdef CONFIG_ARCH_HAS_PKEYS int arch_set_user_pkey_access(int pkey, unsigned long init_val) { - u64 new_por; - u64 old_por; + u8 new_perms; + u64 por; if (!system_supports_poe()) return -ENOSPC; @@ -2320,25 +2320,19 @@ int arch_set_user_pkey_access(int pkey, unsigned long init_val) return -EINVAL; /* Set the bits we need in POR: */ - new_por = POE_RWX; + new_perms = POE_RWX; 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: */ - new_por = POR_ELx_PERM_PREP(pkey, new_por); - - /* Get old POR and mask off any old bits in place: */ - old_por = read_sysreg_s(SYS_POR_EL0); - old_por &= ~(POE_MASK << POR_ELx_PERM_SHIFT(pkey)); - - /* 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_elx_set_pkey_perms(por, pkey, new_perms); + write_sysreg_s(por, SYS_POR_EL0); return 0; } -- 2.51.2