From: catalin.marinas@arm.com (Catalin Marinas) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 8/8] arm64: Enable CONFIG_ARM64_SW_TTBR0_PAN Date: Fri, 28 Oct 2016 18:27:16 +0100 [thread overview] Message-ID: <1477675636-3957-9-git-send-email-catalin.marinas@arm.com> (raw) In-Reply-To: <1477675636-3957-1-git-send-email-catalin.marinas@arm.com> This patch adds the Kconfig option to enable support for TTBR0 PAN emulation. The option is default off because of a slight performance hit when enabled, caused by the additional TTBR0_EL1 switching during user access operations or exception entry/exit code. Cc: Will Deacon <will.deacon@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> --- arch/arm64/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 969ef880d234..6b9a8446fc43 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -790,6 +790,14 @@ config SETEND_EMULATION If unsure, say Y endif +config ARM64_SW_TTBR0_PAN + bool "Emulate Privileged Access Never using TTBR0_EL1 switching" + help + Enabling this option prevents the kernel from accessing + user-space memory directly by pointing TTBR0_EL1 to a reserved + zeroed area and reserved ASID. The user access routines + restore the valid TTBR0_EL1 temporarily. + menu "ARMv8.1 architectural features" config ARM64_HW_AFDBM
WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com> To: linux-arm-kernel@lists.infradead.org Cc: Will Deacon <will.deacon@arm.com>, James Morse <james.morse@arm.com>, Kees Cook <keescook@chromium.org>, Mark Rutland <mark.rutland@arm.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, AKASHI Takahiro <takahiro.akashi@linaro.org>, Sami Tolvanen <samitolvanen@google.com>, kernel-hardening@lists.openwall.com Subject: [kernel-hardening] [PATCH v4 8/8] arm64: Enable CONFIG_ARM64_SW_TTBR0_PAN Date: Fri, 28 Oct 2016 18:27:16 +0100 [thread overview] Message-ID: <1477675636-3957-9-git-send-email-catalin.marinas@arm.com> (raw) In-Reply-To: <1477675636-3957-1-git-send-email-catalin.marinas@arm.com> This patch adds the Kconfig option to enable support for TTBR0 PAN emulation. The option is default off because of a slight performance hit when enabled, caused by the additional TTBR0_EL1 switching during user access operations or exception entry/exit code. Cc: Will Deacon <will.deacon@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> --- arch/arm64/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 969ef880d234..6b9a8446fc43 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -790,6 +790,14 @@ config SETEND_EMULATION If unsure, say Y endif +config ARM64_SW_TTBR0_PAN + bool "Emulate Privileged Access Never using TTBR0_EL1 switching" + help + Enabling this option prevents the kernel from accessing + user-space memory directly by pointing TTBR0_EL1 to a reserved + zeroed area and reserved ASID. The user access routines + restore the valid TTBR0_EL1 temporarily. + menu "ARMv8.1 architectural features" config ARM64_HW_AFDBM
next prev parent reply other threads:[~2016-10-28 17:27 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-10-28 17:27 [PATCH v4 0/8] arm64: Privileged Access Never using TTBR0_EL1 switching Catalin Marinas 2016-10-28 17:27 ` [kernel-hardening] " Catalin Marinas 2016-10-28 17:27 ` [PATCH v4 1/8] arm64: Update the synchronous external abort fault description Catalin Marinas 2016-10-28 17:27 ` [kernel-hardening] " Catalin Marinas 2016-10-28 17:27 ` [PATCH v4 2/8] arm64: Factor out PAN enabling/disabling into separate uaccess_* macros Catalin Marinas 2016-10-28 17:27 ` [kernel-hardening] " Catalin Marinas 2016-10-28 17:27 ` [PATCH v4 3/8] arm64: Factor out TTBR0_EL1 post-update workaround into a specific asm macro Catalin Marinas 2016-10-28 17:27 ` [kernel-hardening] " Catalin Marinas 2016-10-28 17:27 ` [PATCH v4 4/8] arm64: Introduce uaccess_{disable, enable} functionality based on TTBR0_EL1 Catalin Marinas 2016-10-28 17:27 ` [kernel-hardening] [PATCH v4 4/8] arm64: Introduce uaccess_{disable,enable} " Catalin Marinas 2016-10-28 17:27 ` [PATCH v4 5/8] arm64: Disable TTBR0_EL1 during normal kernel execution Catalin Marinas 2016-10-28 17:27 ` [kernel-hardening] " Catalin Marinas 2016-10-28 17:27 ` [PATCH v4 6/8] arm64: Handle faults caused by inadvertent user access with PAN enabled Catalin Marinas 2016-10-28 17:27 ` [kernel-hardening] " Catalin Marinas 2016-10-28 17:27 ` [PATCH v4 7/8] arm64: xen: Enable user access before a privcmd hvc call Catalin Marinas 2016-10-28 17:27 ` [kernel-hardening] " Catalin Marinas 2016-10-28 17:27 ` Catalin Marinas [this message] 2016-10-28 17:27 ` [kernel-hardening] [PATCH v4 8/8] arm64: Enable CONFIG_ARM64_SW_TTBR0_PAN Catalin Marinas
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