[RFC PATCH v4 5/9] x86/cet/ibt: ELF header parsing for IBT
From: Yu-cheng Yu
Date: Fri Sep 21 2018 - 11:10:56 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 | 8 +++++++-
2 files changed, 8 insertions(+), 1 deletion(-)
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 2fddd0bc545b..13358026cd64 100644
--- a/arch/x86/kernel/elf.c
+++ b/arch/x86/kernel/elf.c
@@ -300,7 +300,8 @@ int arch_setup_features(void *ehdr_p, void *phdr_p,
struct elf64_hdr *ehdr64 = ehdr_p;
- if (!cpu_feature_enabled(X86_FEATURE_SHSTK))
+ if (!cpu_feature_enabled(X86_FEATURE_SHSTK) &&
+ !cpu_feature_enabled(X86_FEATURE_IBT))
return 0;
if (ehdr64->e_ident[EI_CLASS] == ELFCLASS64) {
@@ -335,6 +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