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s=arc-20220608; d=hostedemail.com; t=1755248146; a=rsa-sha256; cv=none; b=NeApiY9Ygl6ZDHnz/E9w3SPVuGk5dc2oteM9v+1znNbaNvP8UN6FeqZaOmHp3iZi/z42tO CCnj0IDth2G9d3jpDvtkTD3ScCmgyo2kRl1yvVs7e680AEkiEW4kWyglr/FCVhRMSBTJek CwE8Jfr/CERQTKB6Q9Ko+0n8q982Tk8= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf28.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com 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 A4FEC1E32; Fri, 15 Aug 2025 01:55:37 -0700 (PDT) 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 4DA8C3F63F; Fri, 15 Aug 2025 01:55:41 -0700 (PDT) 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 , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org Subject: [RFC PATCH v5 04/18] arm64: Introduce por_elx_set_pkey_perms() helper Date: Fri, 15 Aug 2025 09:54:58 +0100 Message-ID: <20250815085512.2182322-5-kevin.brodsky@arm.com> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20250815085512.2182322-1-kevin.brodsky@arm.com> References: <20250815085512.2182322-1-kevin.brodsky@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: A5424C0008 X-Stat-Signature: a53zgdnreoaw6j7rhjnwf6qa4oniey1t X-Rspam-User: X-HE-Tag: 1755248146-580964 X-HE-Meta: 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 5wsqlN6I pNgl0OSKRgaHgDAO7Fi3NORc7yfrXshGyZeQzUHK6UTUxTG1cn/DMSb3rooHBFDemMbFT+qo3OPAvIIUYOZdvXl6d+5rJChvKgVKe2e+mnOkvkAskfz7FlU1IrQzvnrHRcobwO6MsXp8k59/uyNGpHswP5BJNvVJIYbyZyWc/bNifGETrPM00DuT2LGzQOdcjOuTBZCq+fIh+GIM= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 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 34e5d78af076..e41ed9e0d799 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1597,8 +1597,8 @@ 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; @@ -1612,25 +1612,19 @@ 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; } -- 2.47.0