[PATCH v8 05/14] x86/cet/ibt: ELF header parsing for IBT

[Yu-cheng Yu]

Look in .note.gnu.property of an ELF file and check if Indirect
Branch Tracking needs to be enabled for the task.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
---
 arch/x86/Kconfig             | 1 +
 arch/x86/kernel/process_64.c | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 666dc66a382e..7edb544cef00 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1971,6 +1971,7 @@ config X86_INTEL_BRANCH_TRACKING_USER
 	select X86_INTEL_CET
 	select ARCH_HAS_AS_LIMIT
 	select ARCH_USE_GNU_PROPERTY
+	select ARCH_BINFMT_ELF_STATE
 	---help---
 	  Indirect Branch Tracking provides hardware protection against return-/jmp-
 	  oriented programming attacks.
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 7ec60b14e96d..a051cfc5242f 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -856,6 +856,11 @@ int arch_setup_property(struct arch_elf_state *state)
 			return r;
 	}
 
+	if (cpu_feature_enabled(X86_FEATURE_IBT)) {
+		if (state->gnu_property & GNU_PROPERTY_X86_FEATURE_1_IBT)
+			r = cet_setup_ibt();
+	}
+
 	return r;
 }
 #endif
-- 
2.17.1