diff --git a/Makefile b/Makefile
index 679f302a8b8b..33dc0d0cdd08 100644
--- a/Makefile
+++ b/Makefile
@@ -866,6 +866,12 @@ ifdef CONFIG_LIVEPATCH
 KBUILD_CFLAGS += $(call cc-option, -flive-patching=inline-clone)
 endif
 
+ifdef CONFIG_SHADOW_CALL_STACK
+CC_FLAGS_SCS	:= -fsanitize=shadow-call-stack
+KBUILD_CFLAGS	+= $(CC_FLAGS_SCS)
+export CC_FLAGS_SCS
+endif
+
 # arch Makefile may override CC so keep this after arch Makefile is included
 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 
diff --git a/arch/Kconfig b/arch/Kconfig
index 786a85d4ad40..334a3d9b19df 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -533,6 +533,30 @@ config STACKPROTECTOR_STRONG
 	  about 20% of all kernel functions, which increases the kernel code
 	  size by about 2%.
 
+config ARCH_SUPPORTS_SHADOW_CALL_STACK
+	bool
+	help
+	  An architecture should select this if it supports Clang's Shadow
+	  Call Stack, has asm/scs.h, and implements runtime support for shadow
+	  stack switching.
+
+config SHADOW_CALL_STACK
+	bool "Clang Shadow Call Stack"
+	depends on CC_IS_CLANG && ARCH_SUPPORTS_SHADOW_CALL_STACK
+	help
+	  This option enables Clang's Shadow Call Stack, which uses a
+	  shadow stack to protect function return addresses from being
+	  overwritten by an attacker. More information can be found in
+	  Clang's documentation:
+
+	    https://clang.llvm.org/docs/ShadowCallStack.html
+
+	  Note that security guarantees in the kernel differ from the
+	  ones documented for user space. The kernel must store addresses
+	  of shadow stacks in memory, which means an attacker capable of
+	  reading and writing arbitrary memory may be able to locate them
+	  and hijack control flow by modifying the stacks.
+
 config HAVE_ARCH_WITHIN_STACK_FRAMES
 	bool
 	help
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index 333a6695a918..18fc4d29ef27 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -42,3 +42,9 @@
  * compilers, like ICC.
  */
 #define barrier() __asm__ __volatile__("" : : : "memory")
+
+#if __has_feature(shadow_call_stack)
+# define __noscs	__attribute__((__no_sanitize__("shadow-call-stack")))
+#else
+# define __noscs
+#endif
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index e970f97a7fcb..97b62f47a80d 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -193,6 +193,10 @@ struct ftrace_likely_data {
 # define randomized_struct_fields_end
 #endif
 
+#ifndef __noscs
+# define __noscs
+#endif
+
 #ifndef asm_volatile_goto
 #define asm_volatile_goto(x...) asm goto(x)
 #endif
diff --git a/include/linux/scs.h b/include/linux/scs.h
new file mode 100644
index 000000000000..060eeb3d1390
--- /dev/null
+++ b/include/linux/scs.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Shadow Call Stack support.
+ *
+ * Copyright (C) 2019 Google LLC
+ */
+
+#ifndef _LINUX_SCS_H
+#define _LINUX_SCS_H
+
+#include <linux/gfp.h>
+#include <linux/poison.h>
+#include <linux/sched.h>
+#include <asm/page.h>
+
+#ifdef CONFIG_SHADOW_CALL_STACK
+
+/*
+ * In testing, 1 KiB shadow stack size (i.e. 128 stack frames on a 64-bit
+ * architecture) provided ~40% safety margin on stack usage while keeping
+ * memory allocation overhead reasonable.
+ */
+#define SCS_SIZE		1024UL
+#define GFP_SCS			(GFP_KERNEL | __GFP_ZERO)
+
+/* An illegal pointer value to mark the end of the shadow stack. */
+#define SCS_END_MAGIC		(0x5f6UL + POISON_POINTER_DELTA)
+
+#define task_scs(tsk)		(task_thread_info(tsk)->scs_base)
+#define task_scs_offset(tsk)	(task_thread_info(tsk)->scs_offset)
+
+extern void scs_init(void);
+
+static inline void scs_task_reset(struct task_struct *tsk)
+{
+	/*
+	 * Reset the shadow stack to the base address in case the task
+	 * is reused.
+	 */
+	task_scs_offset(tsk) = 0;
+}
+
+extern int scs_prepare(struct task_struct *tsk, int node);
+
+static inline unsigned long *__scs_magic(void *s)
+{
+	return (unsigned long *)(s + SCS_SIZE) - 1;
+}
+
+static inline bool scs_corrupted(struct task_struct *tsk)
+{
+	unsigned long *magic = __scs_magic(task_scs(tsk));
+
+	return (task_scs_offset(tsk) >= SCS_SIZE - 1 ||
+		READ_ONCE_NOCHECK(*magic) != SCS_END_MAGIC);
+}
+
+extern void scs_release(struct task_struct *tsk);
+
+#else /* CONFIG_SHADOW_CALL_STACK */
+
+#define task_scs(tsk)	NULL
+
+static inline void scs_init(void) {}
+static inline void scs_task_reset(struct task_struct *tsk) {}
+static inline int scs_prepare(struct task_struct *tsk, int node) { return 0; }
+static inline bool scs_corrupted(struct task_struct *tsk) { return false; }
+static inline void scs_release(struct task_struct *tsk) {}
+
+#endif /* CONFIG_SHADOW_CALL_STACK */
+
+#endif /* _LINUX_SCS_H */
diff --git a/init/init_task.c b/init/init_task.c
index bd403ed3e418..169e34066d35 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -11,6 +11,7 @@
 #include <linux/mm.h>
 #include <linux/audit.h>
 #include <linux/numa.h>
+#include <linux/scs.h>
 
 #include <asm/pgtable.h>
 #include <linux/uaccess.h>
@@ -50,6 +51,13 @@ static struct sighand_struct init_sighand = {
 	.signalfd_wqh	= __WAIT_QUEUE_HEAD_INITIALIZER(init_sighand.signalfd_wqh),
 };
 
+#ifdef CONFIG_SHADOW_CALL_STACK
+unsigned long init_shadow_call_stack[SCS_SIZE / sizeof(long)]
+		__init_task_data = {
+	[(SCS_SIZE / sizeof(long)) - 1] = SCS_END_MAGIC
+};
+#endif
+
 /*
  * Set up the first task table, touch at your own risk!. Base=0,
  * limit=0x1fffff (=2MB)
diff --git a/kernel/Makefile b/kernel/Makefile
index 4cb4130ced32..c332eb9d4841 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -103,6 +103,7 @@ obj-$(CONFIG_TRACEPOINTS) += trace/
 obj-$(CONFIG_IRQ_WORK) += irq_work.o
 obj-$(CONFIG_CPU_PM) += cpu_pm.o
 obj-$(CONFIG_BPF) += bpf/
+obj-$(CONFIG_SHADOW_CALL_STACK) += scs.o
 
 obj-$(CONFIG_PERF_EVENTS) += events/
 
diff --git a/kernel/fork.c b/kernel/fork.c
index 8c700f881d92..f6339f9d232d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -94,6 +94,7 @@
 #include <linux/thread_info.h>
 #include <linux/stackleak.h>
 #include <linux/kasan.h>
+#include <linux/scs.h>
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -456,6 +457,8 @@ void put_task_stack(struct task_struct *tsk)
 
 void free_task(struct task_struct *tsk)
 {
+	scs_release(tsk);
+
 #ifndef CONFIG_THREAD_INFO_IN_TASK
 	/*
 	 * The task is finally done with both the stack and thread_info,
@@ -840,6 +843,8 @@ void __init fork_init(void)
 			  NULL, free_vm_stack_cache);
 #endif
 
+	scs_init();
+
 	lockdep_init_task(&init_task);
 	uprobes_init();
 }
@@ -899,6 +904,10 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 	if (err)
 		goto free_stack;
 
+	err = scs_prepare(tsk, node);
+	if (err)
+		goto free_stack;
+
 #ifdef CONFIG_SECCOMP
 	/*
 	 * We must handle setting up seccomp filters once we're under
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9a2fbf98fd6f..934e03cfaec7 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -11,6 +11,7 @@
 #include <linux/nospec.h>
 
 #include <linux/kcov.h>
+#include <linux/scs.h>
 
 #include <asm/switch_to.h>
 #include <asm/tlb.h>
@@ -6040,6 +6041,7 @@ void init_idle(struct task_struct *idle, int cpu)
 	idle->se.exec_start = sched_clock();
 	idle->flags |= PF_IDLE;
 
+	scs_task_reset(idle);
 	kasan_unpoison_task_stack(idle);
 
 #ifdef CONFIG_SMP
diff --git a/kernel/scs.c b/kernel/scs.c
new file mode 100644
index 000000000000..43624be9ad90
--- /dev/null
+++ b/kernel/scs.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Shadow Call Stack support.
+ *
+ * Copyright (C) 2019 Google LLC
+ */
+
+#include <linux/kasan.h>
+#include <linux/scs.h>
+#include <linux/slab.h>
+#include <asm/scs.h>
+
+static struct kmem_cache *scs_cache;
+
+static void *scs_alloc(int node)
+{
+	void *s;
+
+	s = kmem_cache_alloc_node(scs_cache, GFP_SCS, node);
+	if (s) {
+		*__scs_magic(s) = SCS_END_MAGIC;
+		/*
+		 * Poison the allocation to catch unintentional accesses to
+		 * the shadow stack when KASAN is enabled.
+		 */
+		kasan_poison_object_data(scs_cache, s);
+	}
+
+	return s;
+}
+
+static void scs_free(void *s)
+{
+	kasan_unpoison_object_data(scs_cache, s);
+	kmem_cache_free(scs_cache, s);
+}
+
+void __init scs_init(void)
+{
+	scs_cache = kmem_cache_create("scs_cache", SCS_SIZE, 0, 0, NULL);
+}
+
+int scs_prepare(struct task_struct *tsk, int node)
+{
+	void *s;
+
+	s = scs_alloc(node);
+	if (!s)
+		return -ENOMEM;
+
+	task_scs(tsk) = s;
+	task_scs_offset(tsk) = 0;
+
+	return 0;
+}
+
+void scs_release(struct task_struct *tsk)
+{
+	void *s;
+
+	s = task_scs(tsk);
+	if (!s)
+		return;
+
+	WARN_ON(scs_corrupted(tsk));
+
+	scs_free(s);
+}
