[PATCH v27 05/10] 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>
Cc: Kees Cook <keescook@chromium.org>
---
v27:
- Remove selecting of ARCH_USE_GNU_PROPERTY and ARCH_BINFMT_ELF_STATE,
  since they are already selected by X86_64.

 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 1742c16945ef..607b782afe2c 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -860,6 +860,14 @@ int arch_setup_elf_property(struct arch_elf_state *state)
 		if (state->gnu_property & GNU_PROPERTY_X86_FEATURE_1_SHSTK)
 			r = shstk_setup();
 	}
+
+	if (r < 0)
+		return r;
+
+	if (cpu_feature_enabled(X86_FEATURE_IBT)) {
+		if (state->gnu_property & GNU_PROPERTY_X86_FEATURE_1_IBT)
+			r = ibt_setup();
+	}
 #endif
 
 	return r;
-- 
2.21.0