From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794240088; b=vifBJ51Llrb4rDZUrbpH3166cdgunaFsPHr1RsjsAPacYlFKOirPZQPQKwENbYL9u3RX 7Yy/Hia8FSk/ztep7Xjt+7i1WSPprWsyeuVfjJ4hjaqDhK/M5u97a1Q2zvk1j//aPsJKT nTr65OjQNRrsR7thnEDp0j+L+TBGhZhbc0XvpHvh1MWL4KhPCqY4p2sYt1+8/1y4O75C1 V+ShZITZp41qki+CCQf59eiGwKpQwoaoi/Ss343UZOMYYnEcInXTsFknrcWuFLjaTAayG RW4U8qlBSEjWBYM1spvlpI5IBYze02ngZoIQYSKJWsrmaEkRylLQYy/+Uxd4blvxXhA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794240088; h=DMARC-Filter:Received:Received:DKIM-Signature:From:Date:Subject: MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id: References:In-Reply-To:To:Cc:X-Mailer:X-Developer-Signature: X-Developer-Key; bh=WkMFXub7Ch7CVzwVKxTvrbKX6YcHkbq74bbCbuB4s+0=; b=aqBI16THxhXtE9ESBrEDiSviZ4tHGKmi76GF3pxcbzSB07maXxbKmbKmsEtRWD6Uv1+/ N0wPZp6FUJOAJjFAvDnBvQN2Xio/4VsC+krkIjbu1ZRNHP79YdDetuTOzFjBlPwm7hiQC E9HAPOaV431zI0Q9e4YUxBdexaXPmOkll38n4g7anVr2eN6pbXqi/Isc42LyzOi25tUl1 RRUTLt1qVeuaLz4TNGZyh1U773ZlM5tgchZUA4CJATOfXkzvWCxssFmP3sc6/BbM/dKZu RRSlykd36KVVVskCBzhvkmbgVYahE2+k+b+qKb0AEbEWYpn2sIACwzwP/Rmvzwdgn6A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=RjYaPgri; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 804476083610; Mon, 9 Nov 2026 16:01:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 804476083610 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.a=rsa-sha256 header.s=foss header.b=RjYaPgri 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 0539114BF; Mon, 9 Nov 2026 08:01:24 -0800 (PST) Received: from localhost.localdomain (e123572-lin.cambridge.arm.com [10.2.208.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2A81F3F632; Mon, 9 Nov 2026 08:01:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1794240087; bh=NbWjAbD2XELTG7nVxGNaaZOvGvRplduuBCsN/xKix6E=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=RjYaPgriXPka1kF/SrM93Il1dQjB895z2FYsGkCoMKyXHkliA2wiRqFdBo8+fqGy4 LwptKc1VrggLad0y21pR8zc4Gm6gAlGB7neghthhkDwNCds04HOGdikwc73BbmvHUc 0qPdpnZSIKGj0jJLJjANsNqxfGKqHm/qOEpomxE4= From: Kevin Brodsky Date: Mon, 09 Nov 2026 15:58:35 +0000 Subject: [PATCH RFC v10 10/22] arm64: Enable kpkeys X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261109-kpkeys-v10-10-aa6c4d9603bc@arm.com> References: <20261109-kpkeys-v10-0-aa6c4d9603bc@arm.com> In-Reply-To: <20261109-kpkeys-v10-0-aa6c4d9603bc@arm.com> To: linux-hardening@vger.kernel.org Cc: Kevin Brodsky , Andrew Morton , Ard Biesheuvel , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linu Cherian , Linus Walleij , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , =?utf-8?q?Pierre-Cl=C3=A9ment_Tosi?= , Quentin Perret , Rick Edgecombe , Ryan Roberts , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Ira Weiny , Lorenzo Stoakes , Thomas Gleixner X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1794240029; l=1872; i=kevin.brodsky@arm.com; s=20260427; h=from:subject:message-id; bh=NbWjAbD2XELTG7nVxGNaaZOvGvRplduuBCsN/xKix6E=; b=NKrgEp0VnQpNTn77iTeA0WwI1hEE5wq9WLRIXUoViJ1WrbgIMt4MAliOZ/y9PNzGt/lHPyE3c 05Bq84q7cBVCs1qpbZsAecehL/hibYoaB/dVSgxiZbbmOB/mUzCgyIJ 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. Reviewed-by: Yeoreum Yun 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 1075bc661833..f7e4ffbc07ac 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2300,6 +2300,7 @@ 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 34c5c03c0c9b..42d693197739 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -76,6 +76,7 @@ #include #include #include +#include #include #include @@ -2334,8 +2335,10 @@ 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 -- 2.56.0