From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7E6B6481FC8 for ; Tue, 5 May 2026 16:07:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777997266; cv=none; b=dSNbN9YE/8yIPtmbE//ni6Yoc5JKp0GHr/a2O0H0HYuNjT1Au1UdGxXjhn2JIbg55OdXVntiM9XBv8YXhAFyKSH81CKJfksIsrfdlRQmkyAcJeNQUKNbRbs15xgp2CsAllkvBKUFbVwnOeaNdJRkV7EDoptedrmfqRyxRwQcGe4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777997266; c=relaxed/simple; bh=RQ1NlL4ErKEM1olJpMC90dO11W+OKbU2xg5T/p3fkts=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Ey62q8Ttu0JNPIY0ZQ287fjY2LnlCONCrSCCZneAeivcpZCvfD/7+6WPVYq9TzTf6nb1vN8c4l8QYy7jOlHsBX1C524VI6Jb6bRZCIUiT3MGdcqUQGOWe1rCAyKIHPK3WCfYBz1JHJoTnahrjlHzTCr4gJDzE/fhv/vSDTxvtSY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=vnMHG6Py; arc=none smtp.client-ip=217.140.110.172 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.b="vnMHG6Py" 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 A95A414BF; Tue, 5 May 2026 09:07:39 -0700 (PDT) Received: from localhost.localdomain (e123572-lin.cambridge.arm.com [10.1.194.54]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E30D33F763; Tue, 5 May 2026 09:07:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777997265; bh=RQ1NlL4ErKEM1olJpMC90dO11W+OKbU2xg5T/p3fkts=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=vnMHG6Py7xB+Ho6tj/NB58Zs9avDU9tYneIab9lbKcKBp/P1mjXr1SVjLaGu8qITZ 12D2wQpl3NUvFUzsoSDXEeZu9yKFbpwWdD0E7oUZMoFFwLF4S5FKmhwR/X4wVbIzOq Mu7+tLThErKBv9YsXkGX/OvIlHizLDXi+zBv5C+o= From: Kevin Brodsky Date: Tue, 05 May 2026 17:05:58 +0100 Subject: [PATCH RFC v7 09/24] arm64: Enable kpkeys Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260505-kpkeys-v7-9-20c0bdd97197@arm.com> References: <20260505-kpkeys-v7-0-20c0bdd97197@arm.com> In-Reply-To: <20260505-kpkeys-v7-0-20c0bdd97197@arm.com> To: linux-hardening@vger.kernel.org Cc: Kevin Brodsky , Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Ira Weiny , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , Quentin Perret , Rick Edgecombe , Ryan Roberts , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Lorenzo Stoakes , Thomas Gleixner , Vlastimil Babka X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1777997220; l=1824; i=kevin.brodsky@arm.com; s=20260427; h=from:subject:message-id; bh=RQ1NlL4ErKEM1olJpMC90dO11W+OKbU2xg5T/p3fkts=; b=mANpr2rJlPgxrxGIv4yorvnjURFLTrqouoIxd1Ns63x3UVDAdyZB7Y/1S+4mCFbwHUB6EIf4C WJWbIne57rADDQcp504w7pPD89wjw+pANi4MUSWw5sMIByR+bFjqQ6s X-Developer-Key: i=kevin.brodsky@arm.com; a=ed25519; pk=N2QG+eJKrvkNovwhhwJhnJ4+ScVfsGCHldmqLfcMTFs= This is the final step to enable kpkeys on arm64. We enable POE at EL1 by setting TCR2_EL1.POE, and initialise POR_EL1 to the default value, enabling access to the default pkey/POIndex (0). An ISB is added so that POE restrictions are enforced immediately. Having done this, we can now select ARCH_HAS_KPKEYS if ARM64_POE is enabled. Signed-off-by: Kevin Brodsky --- arch/arm64/Kconfig | 1 + arch/arm64/kernel/cpufeature.c | 5 ++++- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index fe60738e5943..ab06324a50ae 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2145,6 +2145,7 @@ config ARM64_POE def_bool y select ARCH_USES_HIGH_VMA_FLAGS select ARCH_HAS_PKEYS + select ARCH_HAS_KPKEYS help The Permission Overlay Extension is used to implement Memory Protection Keys. Memory Protection Keys provides a mechanism for diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 6d53bb15cf7b..e032322c0c36 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -76,6 +76,7 @@ #include #include #include +#include #include #include @@ -2451,8 +2452,10 @@ static void cpu_enable_mops(const struct arm64_cpu_capabilities *__unused) #ifdef CONFIG_ARM64_POE static void cpu_enable_poe(const struct arm64_cpu_capabilities *__unused) { - sysreg_clear_set(REG_TCR2_EL1, 0, TCR2_EL1_E0POE); + write_sysreg_s(POR_EL1_INIT, SYS_POR_EL1); + sysreg_clear_set(REG_TCR2_EL1, 0, TCR2_EL1_E0POE | TCR2_EL1_POE); sysreg_clear_set(CPACR_EL1, 0, CPACR_EL1_E0POE); + isb(); } #endif -- 2.51.2