[PATCH v21 4/7] x86/cet/ibt: Update ELF header parsing for Indirect Branch Tracking

[Yu-cheng Yu <yu-cheng.yu@intel.com>]

An ELF file's .note.gnu.property indicates features the file supports.
The property is parsed at loading time and passed to arch_setup_elf_
property().  Update it for Indirect Branch Tracking.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/kernel/process_64.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 19f138f7a209..ccf3f66f4d2c 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -864,6 +864,14 @@ int arch_setup_elf_property(struct arch_elf_state *state)
 			r = cet_setup_shstk();
 	}
 
+	if (r < 0)
+		return r;
+
+	if (static_cpu_has(X86_FEATURE_IBT)) {
+		if (state->gnu_property & GNU_PROPERTY_X86_FEATURE_1_IBT)
+			r = cet_setup_ibt();
+	}
+
 	return r;
 }
 #endif
-- 
2.21.0