[RFC PATCH v4 1/9] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking
From: Yu-cheng Yu <hidden>
Date: 2018-09-21 15:11:26
Also in:
linux-api, linux-arch, linux-mm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
The user-mode indirect branch tracking support is done mostly by GCC to insert ENDBR64/ENDBR32 instructions at branch targets. The kernel provides CPUID enumeration, feature MSR setup and the allocation of legacy bitmap. Signed-off-by: Yu-cheng Yu <redacted> --- arch/x86/Kconfig | 12 ++++++++++++ arch/x86/Makefile | 7 +++++++ 2 files changed, 19 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6377125543cc..2a0ff538a229 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig@@ -1941,6 +1941,18 @@ config X86_INTEL_SHADOW_STACK_USER If unsure, say y. +config X86_INTEL_BRANCH_TRACKING_USER + prompt "Intel Indirect Branch Tracking for user-mode" + def_bool n + depends on CPU_SUP_INTEL && X86_64 + select X86_INTEL_CET + select ARCH_HAS_PROGRAM_PROPERTIES + ---help--- + Indirect Branch Tracking provides hardware protection against return-/jmp- + oriented programming attacks. + + If unsure, say y + config EFI bool "EFI runtime service support" depends on ACPI
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index b28842b80295..ff652bba849f 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile@@ -159,6 +159,13 @@ ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER endif endif +# Check compiler ibt support +ifdef CONFIG_X86_INTEL_BRANCH_TRACKING_USER + ifeq ($(call cc-option-yn, -fcf-protection=branch), n) + $(error CONFIG_X86_INTEL_BRANCH_TRACKING_USER not supported by compiler) + endif +endif + # # If the function graph tracer is used with mcount instead of fentry, # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
--
2.17.1