From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Rutland Subject: [PATCHv3 04/11] arm64: Don't trap host pointer auth use to EL2 Date: Tue, 17 Apr 2018 19:37:28 +0100 Message-ID: <20180417183735.56985-5-mark.rutland@arm.com> References: <20180417183735.56985-1-mark.rutland@arm.com> Return-path: In-Reply-To: <20180417183735.56985-1-mark.rutland@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-arm-kernel@lists.infradead.org Cc: arnd@arndb.de, catalin.marinas@arm.com, cdall@kernel.org, drjones@redhat.com, kvmarm@lists.cs.columbia.edu, linux-arch@vger.kernel.org, marc.zyngier@arm.com, mark.rutland@arm.com, ramana.radhakrishnan@arm.com, suzuki.poulose@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, awallis@codeaurora.org, kernel-hardening@lists.openwall.com List-Id: linux-arch.vger.kernel.org To allow EL0 (and/or EL1) to use pointer authentication functionality, we must ensure that pointer authentication instructions and accesses to pointer authentication keys are not trapped to EL2. This patch ensures that HCR_EL2 is configured appropriately when the kernel is booted at EL2. For non-VHE kernels we set HCR_EL2.{API,APK}, ensuring that EL1 can access keys and permit EL0 use of instructions. For VHE kernels host EL0 (TGE && E2H) is unaffected by these settings, and it doesn't matter how we configure HCR_EL2.{API,APK}, so we don't bother setting them. This does not enable support for KVM guests, since KVM manages HCR_EL2 itself when running VMs. Signed-off-by: Mark Rutland Cc: Christoffer Dall Cc: Catalin Marinas Cc: Marc Zyngier Cc: Will Deacon Cc: kvmarm@lists.cs.columbia.edu --- arch/arm64/include/asm/kvm_arm.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 89b3dda7e3cb..4d57e1e58323 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -23,6 +23,8 @@ #include /* Hyp Configuration Register (HCR) bits */ +#define HCR_API (UL(1) << 41) +#define HCR_APK (UL(1) << 40) #define HCR_TEA (UL(1) << 37) #define HCR_TERR (UL(1) << 36) #define HCR_TLOR (UL(1) << 35) @@ -86,7 +88,7 @@ HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \ HCR_FMO | HCR_IMO) #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF) -#define HCR_HOST_NVHE_FLAGS (HCR_RW) +#define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK) #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H) /* TCR_EL2 Registers bits */ -- 2.11.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com ([217.140.101.70]:46984 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752604AbeDQSh6 (ORCPT ); Tue, 17 Apr 2018 14:37:58 -0400 From: Mark Rutland Subject: [PATCHv3 04/11] arm64: Don't trap host pointer auth use to EL2 Date: Tue, 17 Apr 2018 19:37:28 +0100 Message-ID: <20180417183735.56985-5-mark.rutland@arm.com> In-Reply-To: <20180417183735.56985-1-mark.rutland@arm.com> References: <20180417183735.56985-1-mark.rutland@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-arm-kernel@lists.infradead.org Cc: arnd@arndb.de, catalin.marinas@arm.com, cdall@kernel.org, drjones@redhat.com, kvmarm@lists.cs.columbia.edu, linux-arch@vger.kernel.org, marc.zyngier@arm.com, mark.rutland@arm.com, ramana.radhakrishnan@arm.com, suzuki.poulose@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, awallis@codeaurora.org, kernel-hardening@lists.openwall.com Message-ID: <20180417183728.nMqUJt0Fx2kPHA7GXIFjVGIi8JLGK_-asjVJlB-LMPc@z> To allow EL0 (and/or EL1) to use pointer authentication functionality, we must ensure that pointer authentication instructions and accesses to pointer authentication keys are not trapped to EL2. This patch ensures that HCR_EL2 is configured appropriately when the kernel is booted at EL2. For non-VHE kernels we set HCR_EL2.{API,APK}, ensuring that EL1 can access keys and permit EL0 use of instructions. For VHE kernels host EL0 (TGE && E2H) is unaffected by these settings, and it doesn't matter how we configure HCR_EL2.{API,APK}, so we don't bother setting them. This does not enable support for KVM guests, since KVM manages HCR_EL2 itself when running VMs. Signed-off-by: Mark Rutland Cc: Christoffer Dall Cc: Catalin Marinas Cc: Marc Zyngier Cc: Will Deacon Cc: kvmarm@lists.cs.columbia.edu --- arch/arm64/include/asm/kvm_arm.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 89b3dda7e3cb..4d57e1e58323 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -23,6 +23,8 @@ #include /* Hyp Configuration Register (HCR) bits */ +#define HCR_API (UL(1) << 41) +#define HCR_APK (UL(1) << 40) #define HCR_TEA (UL(1) << 37) #define HCR_TERR (UL(1) << 36) #define HCR_TLOR (UL(1) << 35) @@ -86,7 +88,7 @@ HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \ HCR_FMO | HCR_IMO) #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF) -#define HCR_HOST_NVHE_FLAGS (HCR_RW) +#define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK) #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H) /* TCR_EL2 Registers bits */ -- 2.11.0