[PATCH 1/7] x86/cet: Add Kconfig option for user-mode Indirect Branch Tracking

[Yu-cheng Yu]

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 <yu-cheng.yu@xxxxxxxxx>
---
 arch/x86/Kconfig | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 24339a5299da..27bfbd137fbe 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1953,6 +1953,18 @@ 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 programing attacks.
+
+	  If unsure, say y
+
 config EFI
 	bool "EFI runtime service support"
 	depends on ACPI
-- 
2.15.1