Messages in this thread Patch in this message | | | From | Rick Edgecombe <> | Subject | [PATCH v2 02/39] x86/cet/shstk: Add Kconfig option for Shadow Stack | Date | Thu, 29 Sep 2022 15:28:59 -0700 |
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From: Yu-cheng Yu <yu-cheng.yu@intel.com>
Shadow Stack provides protection against function return address corruption. It is active when the processor supports it, the kernel has CONFIG_X86_SHADOW_STACK enabled, and the application is built for the feature. This is only implemented for the 64-bit kernel. When it is enabled, legacy non-Shadow Stack applications continue to work, but without protection.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: Kees Cook <keescook@chromium.org>
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v2: - Remove already wrong kernel size increase info (tlgx) - Change prompt to remove "Intel" (tglx) - Update line about what CPUs are supported (Dave)
Yu-cheng v25: - Remove X86_CET and use X86_SHADOW_STACK directly.
Yu-cheng v24: - Update for the splitting X86_CET to X86_SHADOW_STACK and X86_IBT.
arch/x86/Kconfig | 18 ++++++++++++++++++ arch/x86/Kconfig.assembler | 5 +++++ 2 files changed, 23 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f9920f1341c8..b68eb75887b8 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -26,6 +26,7 @@ config X86_64 depends on 64BIT # Options that are inherently 64-bit kernel only: select ARCH_HAS_GIGANTIC_PAGE + select ARCH_HAS_SHADOW_STACK select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 select ARCH_USE_CMPXCHG_LOCKREF select HAVE_ARCH_SOFT_DIRTY @@ -1936,6 +1937,23 @@ config X86_SGX If unsure, say N. +config ARCH_HAS_SHADOW_STACK + def_bool n + +config X86_SHADOW_STACK + prompt "X86 Shadow Stack" + def_bool n + depends on ARCH_HAS_SHADOW_STACK + select ARCH_USES_HIGH_VMA_FLAGS + help + Shadow Stack protection is a hardware feature that detects function + return address corruption. Today the kernel's support is limited to + virtualizing it in KVM guests. + + CPUs supporting shadow stacks were first released in 2020. + + If unsure, say N. + config EFI bool "EFI runtime service support" depends on ACPI diff --git a/arch/x86/Kconfig.assembler b/arch/x86/Kconfig.assembler index 26b8c08e2fc4..00c79dd93651 100644 --- a/arch/x86/Kconfig.assembler +++ b/arch/x86/Kconfig.assembler @@ -19,3 +19,8 @@ config AS_TPAUSE def_bool $(as-instr,tpause %ecx) help Supported by binutils >= 2.31.1 and LLVM integrated assembler >= V7 + +config AS_WRUSS + def_bool $(as-instr,wrussq %rax$(comma)(%rbx)) + help + Supported by binutils >= 2.31 and LLVM integrated assembler -- 2.17.1
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