@@ -114,6 +114,9 @@ enum xfeature {
 	XFEATURE_Hi16_ZMM,
 	XFEATURE_PT_UNIMPLEMENTED_SO_FAR,
 	XFEATURE_PKRU,
+	XFEATURE_RESERVED,
+	XFEATURE_SHSTK_USER,
+	XFEATURE_SHSTK_KERNEL,
 
 	XFEATURE_MAX,
 };

@@ -128,6 +131,8 @@ enum xfeature {
 #define XFEATURE_MASK_Hi16_ZMM		(1 << XFEATURE_Hi16_ZMM)
 #define XFEATURE_MASK_PT		(1 << XFEATURE_PT_UNIMPLEMENTED_SO_FAR)
 #define XFEATURE_MASK_PKRU		(1 << XFEATURE_PKRU)
+#define XFEATURE_MASK_SHSTK_USER	(1 << XFEATURE_SHSTK_USER)
+#define XFEATURE_MASK_SHSTK_KERNEL	(1 << XFEATURE_SHSTK_KERNEL)
 
 #define XFEATURE_MASK_FPSSE		(XFEATURE_MASK_FP | XFEATURE_MASK_SSE)
 #define XFEATURE_MASK_AVX512		(XFEATURE_MASK_OPMASK \

@@ -229,6 +234,23 @@ struct pkru_state {
 	u32				pad;
 } __packed;
 
+/*
+ * State component 11 is Control flow Enforcement user states
+ */
+struct cet_user_state {
+	u64 u_cet;	/* user control flow settings */
+	u64 user_ssp;	/* user shadow stack pointer */
+} __packed;
+
+/*
+ * State component 12 is Control flow Enforcement kernel states
+ */
+struct cet_kernel_state {
+	u64 kernel_ssp;	/* kernel shadow stack */
+	u64 pl1_ssp;	/* ring-1 shadow stack */
+	u64 pl2_ssp;	/* ring-2 shadow stack */
+} __packed;
+
 struct xstate_header {
 	u64				xfeatures;
 	u64				xcomp_bv;

@@ -28,7 +28,9 @@
 				  XFEATURE_MASK_Hi16_ZMM | \
 				  XFEATURE_MASK_PKRU | \
 				  XFEATURE_MASK_BNDREGS | \
-				  XFEATURE_MASK_BNDCSR)
+				  XFEATURE_MASK_BNDCSR | \
+				  XFEATURE_MASK_SHSTK_USER | \
+				  XFEATURE_MASK_SHSTK_KERNEL)
 
 #ifdef CONFIG_X86_64
 #define REX_PREFIX	"0x48, "

@@ -130,6 +130,8 @@
 #define X86_CR4_SMAP		_BITUL(X86_CR4_SMAP_BIT)
 #define X86_CR4_PKE_BIT		22 /* enable Protection Keys support */
 #define X86_CR4_PKE		_BITUL(X86_CR4_PKE_BIT)
+#define X86_CR4_CET_BIT		23 /* enable Control flow Enforcement */
+#define X86_CR4_CET		_BITUL(X86_CR4_CET_BIT)
 
 /*
  * x86-64 Task Priority Register, CR8

@@ -35,6 +35,9 @@ static const char *xfeature_names[] =
 	"Processor Trace (unused)"	,
 	"Protection Keys User registers",
 	"unknown xstate feature"	,
+	"Control flow User registers"	,
+	"Control flow Kernel registers"	,
+	"unknown xstate feature"	,
 };
 
 static short xsave_cpuid_features[] __initdata = {

@@ -48,6 +51,9 @@ static short xsave_cpuid_features[] __initdata = {
 	X86_FEATURE_AVX512F,
 	X86_FEATURE_INTEL_PT,
 	X86_FEATURE_PKU,
+	0,		   /* Unused */
+	X86_FEATURE_SHSTK, /* XFEATURE_SHSTK_USER */
+	X86_FEATURE_SHSTK, /* XFEATURE_SHSTK_KERNEL */
 };
 
 /*

@@ -312,6 +318,8 @@ static void __init print_xstate_features(void)
 	print_xstate_feature(XFEATURE_MASK_ZMM_Hi256);
 	print_xstate_feature(XFEATURE_MASK_Hi16_ZMM);
 	print_xstate_feature(XFEATURE_MASK_PKRU);
+	print_xstate_feature(XFEATURE_MASK_SHSTK_USER);
+	print_xstate_feature(XFEATURE_MASK_SHSTK_KERNEL);
 }
 
 /*

@@ -558,6 +566,8 @@ static void check_xstate_against_struct(int nr)
 	XCHECK_SZ(sz, nr, XFEATURE_ZMM_Hi256, struct avx_512_zmm_uppers_state);
 	XCHECK_SZ(sz, nr, XFEATURE_Hi16_ZMM,  struct avx_512_hi16_state);
 	XCHECK_SZ(sz, nr, XFEATURE_PKRU,      struct pkru_state);
+	XCHECK_SZ(sz, nr, XFEATURE_SHSTK_USER,   struct cet_user_state);
+	XCHECK_SZ(sz, nr, XFEATURE_SHSTK_KERNEL, struct cet_kernel_state);
 
 	/*
 	 * Make *SURE* to add any feature numbers in below if