[PATCH v5 05/11] x86/cet/ibt: ELF header parsing for IBT

From: Yu-cheng Yu
Date: Thu Oct 11 2018 - 11:22:42 EST


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: H.J. Lu <hjl.tools@xxxxxxxxx>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
---
arch/x86/include/uapi/asm/elf_property.h | 1 +
arch/x86/kernel/elf.c | 5 +++++
2 files changed, 6 insertions(+)

diff --git a/arch/x86/include/uapi/asm/elf_property.h b/arch/x86/include/uapi/asm/elf_property.h
index af361207718c..343a871b8fc1 100644
--- a/arch/x86/include/uapi/asm/elf_property.h
+++ b/arch/x86/include/uapi/asm/elf_property.h
@@ -11,5 +11,6 @@
* Bits for GNU_PROPERTY_X86_FEATURE_1_AND
*/
#define GNU_PROPERTY_X86_FEATURE_1_SHSTK (0x00000002)
+#define GNU_PROPERTY_X86_FEATURE_1_IBT (0x00000001)

#endif /* _UAPI_ASM_X86_ELF_PROPERTY_H */
diff --git a/arch/x86/kernel/elf.c b/arch/x86/kernel/elf.c
index 2e2030a0462b..177b5144fdf4 100644
--- a/arch/x86/kernel/elf.c
+++ b/arch/x86/kernel/elf.c
@@ -336,6 +336,11 @@ int arch_setup_features(void *ehdr_p, void *phdr_p,
}
}

+ if (cpu_feature_enabled(X86_FEATURE_IBT)) {
+ if (feature & GNU_PROPERTY_X86_FEATURE_1_IBT)
+ err = cet_setup_ibt();
+ }
+
out:
return err;
}
--
2.17.1