diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
index ec256ae27a31..5cc4be6e0982 100644
--- a/arch/x86/kernel/cet.c
+++ b/arch/x86/kernel/cet.c

@@ -46,6 +47,69 @@ static unsigned long get_shstk_addr(void)
 	return ptr;
 }
 
+/*
+ * Verify the restore token at the address of 'ssp' is
+ * valid and then set shadow stack pointer according to the
+ * token.
+ */
+static int verify_rstor_token(bool ia32, unsigned long ssp,
+			      unsigned long *new_ssp)
+{
+	unsigned long token;
+
+	*new_ssp = 0;
+
+	if (!IS_ALIGNED(ssp, 8))
+		return -EINVAL;
+
+	if (get_user(token, (unsigned long __user *)ssp))
+		return -EFAULT;
+

+		return -EFAULT;
+
+	*new_ssp = addr;
+	return 0;
+}
+
 int cet_setup_shstk(void)
 {
 	unsigned long addr, size;

@@ -107,3 +171,54 @@ void cet_disable_free_shstk(struct task_struct *tsk)
 
 	tsk->thread.cet.shstk_enabled = 0;
 }
+
+int cet_restore_signal(unsigned long ssp)
+{
+	unsigned long new_ssp;
+	int err;
+
+	if (!current->thread.cet.shstk_enabled)
+		return 0;
+
+	err = verify_rstor_token(in_ia32_syscall(), ssp, &new_ssp);
+
+	if (err)
+		return err;
+
+	return set_shstk_ptr(new_ssp);
+}
+
+/*
+ * Setup the shadow stack for the signal handler: first,
+ * create a restore token to keep track of the current ssp,
+ * and then the return address of the signal handler.
+ */
+int cet_setup_signal(bool ia32, unsigned long rstor_addr,
+		     unsigned long *new_ssp)
+{
+	unsigned long ssp;
+	int err;
+
+	if (!current->thread.cet.shstk_enabled)
+		return 0;
+
+	ssp = get_shstk_addr();
+	err = create_rstor_token(ia32, ssp, new_ssp);
+
+	if (err)
+		return err;
+
+	if (ia32) {
+		ssp = *new_ssp - sizeof(u32);
+		err = write_user_shstk_32(ssp, (unsigned int)rstor_addr);
+	} else {
+		ssp = *new_ssp - sizeof(u64);
+		err = write_user_shstk_64(ssp, rstor_addr);
+	}
+
+	if (err)
+		return err;
+
+	set_shstk_ptr(ssp);
+	return 0;
+}

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 92a3b312a53c..e9a85689143f 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c

@@ -46,6 +46,7 @@
 
 #include <asm/sigframe.h>
 #include <asm/signal.h>
+#include <asm/cet.h>
 
 #define COPY(x)			do {			\
 	get_user_ex(regs->x, &sc->x);			\

@@ -152,6 +153,10 @@ static int restore_sigcontext(struct pt_regs *regs,
 
 	err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32));
 
+#ifdef CONFIG_X86_64
+	err |= restore_sigcontext_ext(buf);
+#endif
+
 	force_iret();
 
 	return err;

@@ -266,6 +271,11 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 	}
 

 		*fpstate = (void __user *)sp;

@@ -493,6 +503,9 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
 	err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 
+	if (!err)
+		err = setup_sigcontext_ext(ksig, fp);
+

 	if (err)
 		return -EFAULT;
 

@@ -576,6 +589,9 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
 				regs, set->sig[0]);
 	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 
+	if (!err)
+		err = setup_sigcontext_ext(ksig, fpstate);
+
 	if (err)
 		return -EFAULT;
 

@@ -707,6 +723,86 @@ setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
 	}
 }
 
+#ifdef CONFIG_X86_64
+static int copy_ext_from_user(struct sc_ext *ext, void __user *fpu)
+{
+	void __user *p;
+
+	if (!fpu)
+		return -EINVAL;
+
+	p = fpu + fpu_user_xstate_size + FP_XSTATE_MAGIC2_SIZE;
+	p = (void __user *)ALIGN((unsigned long)p, 8);
+
+	if (!access_ok(VERIFY_READ, p, sizeof(*ext)))
+		return -EFAULT;
+
+	if (__copy_from_user(ext, p, sizeof(*ext)))
+		return -EFAULT;
+
+	if (ext->total_size != sizeof(*ext))
+		return -EINVAL;
+	return 0;
+}
+
+static int copy_ext_to_user(void __user *fpu, struct sc_ext *ext)
+{
+	void __user *p;
+
+	if (!fpu)
+		return -EINVAL;
+
+	if (ext->total_size != sizeof(*ext))
+		return -EINVAL;
+
+	p = fpu + fpu_user_xstate_size + FP_XSTATE_MAGIC2_SIZE;
+	p = (void __user *)ALIGN((unsigned long)p, 8);
+
+	if (!access_ok(VERIFY_WRITE, p, sizeof(*ext)))
+		return -EFAULT;
+
+	if (__copy_to_user(p, ext, sizeof(*ext)))
+		return -EFAULT;
+
+	return 0;
+}
+
+int restore_sigcontext_ext(void __user *fp)
+{
+	int err = 0;
+
+	if (boot_cpu_has(X86_FEATURE_SHSTK) && fp) {
+		struct sc_ext ext = {0, 0};
+
+		err = copy_ext_from_user(&ext, fp);
+
+		if (!err)
+			err = cet_restore_signal(ext.ssp);
+	}
+
+	return err;
+}
+
+int setup_sigcontext_ext(struct ksignal *ksig, void __user *fp)
+{
+	int err = 0;
+
+	if (boot_cpu_has(X86_FEATURE_SHSTK) && fp) {
+		struct sc_ext ext = {0, 0};
+		unsigned long rstor;
+
+		rstor = (unsigned long)ksig->ka.sa.sa_restorer;
+		err = cet_setup_signal(is_ia32_frame(ksig), rstor, &ext.ssp);
+		if (!err) {
+			ext.total_size = sizeof(ext);
+			err = copy_ext_to_user(fp, &ext);
+		}
+	}
+
+	return err;
+}
+#endif
+
 static void
 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 {

-- 
2.17.1