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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-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 4C3D640009 X-Stat-Signature: npje75fumbd7qejz31czz7g6hzsykoyt X-HE-Tag: 1738577998-353607 X-HE-Meta: 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 olBH+UPT CQ4pcco/q3TqXNoJFiDuACVcplX0/fnbfYcYHjB7Va0374uapIVrx6oXC3cJNxNg1q4EEIcmOdv35PS32fG+H6tAGrzq8e/Ear7VLVBMCt/FfW3/EyKeol+ZfDMEXfXYoJRYbrJT1b46xC7aNogwWN2tyVwH/dvq6i1aeFroOv95WtIAh1PugFN4XzlTQQXWd9B88+gNBywKJKIQ= 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(). 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; }