From nobody Tue Apr 7 19:54:18 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 64ACD3624D1; Fri, 27 Feb 2026 17:56:07 +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=1772214968; cv=none; b=JU+f5NIJYvzQ3HQupPBUsdAS0uFHXa60pcOIHXX0X9pzjGeOFt/uym/DKfPwumCwIg4IikDVr32NoMW+j340GBc0XGMt9MRv6aO6UXALZtTeiSCM8676w+g67jPCYiksiw+SSY74FWyCOYuUxTXDX3LHz/MReoQ2gXOVkCB+tVg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772214968; c=relaxed/simple; bh=EvFUJeSR9svJsMZsCfng7S0HacfWceQByYcu35yJ9gg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rs40P3N19mgGlRF3bJp5CBuEhCtHydaHc8pn5LBTGHrS5MrSlck+VKuhKs7IZqcY+gApXz8pGyjPyd3zOSeJ2ToIy1cc37DSzwxROW++vEHmKZj1rM43PDhQfoH/nRJqu8SZIVN2aEu8M0n1wKJYo0FtW/9AhTefyXM4+LaL70s= 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; 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 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 AE2D614BF; Fri, 27 Feb 2026 09:56:00 -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 936263F73B; Fri, 27 Feb 2026 09:56:02 -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 05/30] arm64: Implement asm/kpkeys.h using POE Date: Fri, 27 Feb 2026 17:54:53 +0000 Message-ID: <20260227175518.3728055-6-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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Implement the kpkeys interface if CONFIG_ARM64_POE is enabled. The permissions for KPKEYS_PKEY_DEFAULT (pkey 0) are set to RWX as this pkey is also used for code mappings. Signed-off-by: Kevin Brodsky --- arch/arm64/include/asm/kpkeys.h | 49 +++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 arch/arm64/include/asm/kpkeys.h diff --git a/arch/arm64/include/asm/kpkeys.h b/arch/arm64/include/asm/kpkey= s.h new file mode 100644 index 000000000000..3b0ab5e7dd22 --- /dev/null +++ b/arch/arm64/include/asm/kpkeys.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __ASM_KPKEYS_H +#define __ASM_KPKEYS_H + +#include +#include +#include + +#include + +static inline bool arch_kpkeys_enabled(void) +{ + return system_supports_poe(); +} + +#ifdef CONFIG_ARM64_POE + +static inline u64 por_set_kpkeys_level(u64 por, int level) +{ + por =3D por_elx_set_pkey_perms(por, KPKEYS_PKEY_DEFAULT, POE_RWX); + + return por; +} + +static __always_inline void __kpkeys_set_pkey_reg_nosync(u64 pkey_reg) +{ + write_sysreg_s(pkey_reg, SYS_POR_EL1); +} + +static __always_inline int arch_kpkeys_set_level(int level) +{ + u64 prev_por =3D read_sysreg_s(SYS_POR_EL1); + u64 new_por =3D por_set_kpkeys_level(prev_por, level); + + __kpkeys_set_pkey_reg_nosync(new_por); + isb(); + + return prev_por; +} + +static __always_inline void arch_kpkeys_restore_pkey_reg(u64 pkey_reg) +{ + __kpkeys_set_pkey_reg_nosync(pkey_reg); + isb(); +} + +#endif /* CONFIG_ARM64_POE */ + +#endif /* __ASM_KPKEYS_H */ --=20 2.51.2