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imf26.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf26.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772214963; a=rsa-sha256; cv=none; b=OcPJOOwT+6y73+Tu+SCZsYasMV7dU0EHpk6RBLCKq/asWA6jDA8xZg5rXxDDvKkdRO6rod zJh8joZD2NuMjRyJEYQd/jWGZaSnLNNvr4JOfSnLB8IXZULKxHimlkIsh/CCVLw0IA5+dC 8QwpqEuNBBj5WMcBEkoXDHzauz6d968= 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 017AB1516; Fri, 27 Feb 2026 09:55:56 -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 DEC843F73B; Fri, 27 Feb 2026 09:55:57 -0800 (PST) From: Kevin Brodsky To: linux-hardening@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Kevin Brodsky , Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , David Hildenbrand , Ira Weiny , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Lorenzo Stoakes , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , Quentin Perret , Rick Edgecombe , Ryan Roberts , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org Subject: [PATCH v6 04/30] arm64: Introduce por_elx_set_pkey_perms() helper Date: Fri, 27 Feb 2026 17:54:52 +0000 Message-ID: <20260227175518.3728055-5-kevin.brodsky@arm.com> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20260227175518.3728055-1-kevin.brodsky@arm.com> References: <20260227175518.3728055-1-kevin.brodsky@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 23CE0140013 X-Stat-Signature: uwmksx9g6fyjjhb1h8r8emdbn13an4zo X-Rspam-User: X-HE-Tag: 1772214962-571959 X-HE-Meta: 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 T5YKyL4R YJpFw3HxgyyRP/Vi9oA5RqCeIbwNQ4qg46DxyIYd78FbQD3di7O95Cc2hplLZhcqkm+GR0Ke8ENV2SK+ycu4MeJRnz+JY0tY3lcNjMlqCzO1tY3XC7aDPZuevnzTgA0QPA5LtUx+3xL4uO+FxzRu1yltKeVNYDGNgpoVVQY7aVm8tBEAtbvs5Lk6vbirtVFvflO+/aJCkzLFYkcE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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(). 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..bffb4d2b1246 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, u64 perms) +{ + u64 shift = POR_ELx_PERM_SHIFT(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 a6a00accf4f9..09ca62f77a84 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -2208,8 +2208,8 @@ 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; - u64 old_por; + u64 new_perms; + u64 por; if (!system_supports_poe()) return -ENOSPC; @@ -2223,25 +2223,19 @@ 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_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