Thread (17 messages) 17 messages, 2 authors, 2018-11-19

[RFC PATCH v6 05/11] x86/cet/ibt: ELF header parsing for IBT

From: Yu-cheng Yu <hidden>
Date: 2018-11-19 21:55:48
Also in: linux-arch, linux-doc, linux-mm, lkml
Subsystem: the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

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 <redacted>
Signed-off-by: Yu-cheng Yu <redacted>
---
 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 60e396e2abe9..7727b9332097 100644
--- a/arch/x86/kernel/elf.c
+++ b/arch/x86/kernel/elf.c
@@ -353,6 +353,11 @@ 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
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