1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/include/asm/ibt.h b/arch/x86/include/asm/ibt.h
index 52fb05d66489..689880eca9ba 100644
--- a/arch/x86/include/asm/ibt.h
+++ b/arch/x86/include/asm/ibt.h
@@ -46,8 +46,20 @@ static inline __attribute_const__ u32 gen_endbr(void)
 	return endbr;
 }
 
+static inline __attribute_const__ u32 gen_endbr_poison(void)
+{
+	/*
+	 * 4 byte NOP that isn't NOP4 (in fact it is OSP NOP3), such that it
+	 * will be unique to (former) ENDBR sites.
+	 */
+	return 0x001f0f66; /* osp nopl (%rax) */
+}
+
 static inline bool is_endbr(u32 val)
 {
+	if (val == gen_endbr_poison())
+		return true;
+
 	val &= ~0x01000000U; /* ENDBR32 -> ENDBR64 */
 	return val == gen_endbr();
 }