From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794240052; b=Zb5ctSdeJVIJXBlCvcsL13uT2VN5Stw+7w6UNh0KG/mdRjQ3hx1qWxBEIHYl1CbJMX9v 0kvwQBlfIGWqhaWqY8pnq409qLduIJZrvMgDqa4GUtvReznc9fyM3mfBiAU78vdPg+5Eh d8VZzKQ0vbUI9lcJOZDWkoPkJwFseLhTKkqTRNQcW4C3+M4KsBJKFA/KPVAvfsXUGswQY EdO5IH3qyOznshILmPkirKO2Cti/qF8AMSYC5WGZP+qs7XXsrzBSi/WkI4HOaIB4cfBkN VmRZdrJxCkV6sbBMjgHop+CUWlMsBIN12dKSmcfidM3MeOToZlT06nvi0qaQ8zsZ4Fg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794240052; h=DMARC-Filter:Received:Received:DKIM-Signature:From:Date:Subject: MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id: References:In-Reply-To:To:Cc:X-Mailer:X-Developer-Signature: X-Developer-Key; bh=pnRsN3UInd8vk5PQMkeB0kwLm5CfKQbQi8xN3upHdxI=; b=W+w0d+8URKb0FVMxTq08EdwPihVg4Ko4afi9fNLh5L9+rYDSLfivtTES/cLl6KbaKymf IlxuaAYY6lIIX25bHzRXbyAAIUvrtG0F12SGusnvhv/lM0nmZL0x1mhQCRfth1klSgC16 7icsa+Vi7jJz0Ed2OAf3b3En4lCqv4l+Ru6A+eEIg9vP+jEYZQynzX2cdyT07y1txQVRY +M+8it7nqP6J6KIhiYnCspXFtikGTgpVJ2cCFVrhagVBLA6m22bGRsBzij8GqXi4GbDQd YokyZpAjrha+ah/W/8Typf1wjrE2rWN1K3+EaFTemZO0/mwtJ7AnzaKVU9pRvEWVPsQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=QMPDGWx1; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 3161B60A2614; Mon, 9 Nov 2026 16:00:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 3161B60A2614 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=QMPDGWx1 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 848A91516; Mon, 9 Nov 2026 08:00:47 -0800 (PST) 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 A74473F632; Mon, 9 Nov 2026 08:00:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1794240050; bh=yu0QibpeGnCkZqJmw/urIy0ljAA1TeHqyJFGcmLJNXM=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=QMPDGWx1tZHs3n/XgKWaaBFrrMKY/A63uGRHamj8PoWWPP+KJ0EThMIXjNQCaYx84 2Iwh9VkjamsvtEIYpenncdUwbaUqE1VgIROx/qAtqOaIci/I2xN2tx3zwa2VjNzQTR jVZtia/5iorciBFQMOvItpdqalF6h9JQ4H2/fwmU= From: Kevin Brodsky Date: Mon, 09 Nov 2026 15:58:28 +0000 Subject: [PATCH RFC v10 03/22] arm64: Introduce por_elx_set_pkey_perms() helper X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261109-kpkeys-v10-3-aa6c4d9603bc@arm.com> References: <20261109-kpkeys-v10-0-aa6c4d9603bc@arm.com> In-Reply-To: <20261109-kpkeys-v10-0-aa6c4d9603bc@arm.com> To: linux-hardening@vger.kernel.org Cc: Kevin Brodsky , Andrew Morton , Ard Biesheuvel , 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-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Ira Weiny , Lorenzo Stoakes , Thomas Gleixner X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1794240029; l=2726; i=kevin.brodsky@arm.com; s=20260427; h=from:subject:message-id; bh=yu0QibpeGnCkZqJmw/urIy0ljAA1TeHqyJFGcmLJNXM=; b=aKAWRrAYSHwHgbIVvJMgI7Rd+w4FuN/S6jHgMLHn8JPU2JUOellnb/4EKTjnO9xnQBIXtnWa/ 53OE2mItuJMDGFHWn7ehHKcQwtnlSNhWdwJzXSbq3HUq9MmYLuEbxGi X-Developer-Key: i=kevin.brodsky@arm.com; a=ed25519; pk=N2QG+eJKrvkNovwhhwJhnJ4+ScVfsGCHldmqLfcMTFs= 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(). Use field_prep() to encode the new permissions because the field mask depends on the pkey index. 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) Reviewed-by: Yeoreum Yun 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..66d8c9a73224 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 mask = POE_MASK << POR_ELx_PERM_SHIFT(pkey); + + return (por & ~mask) | field_prep(mask, perms); +} + #endif /* _ASM_ARM64_POR_H */ diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 140520b351e2..6a2155db3d05 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -2355,8 +2355,8 @@ 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; @@ -2370,25 +2370,19 @@ 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; } -- 2.56.0