diff --git a/fs/exec.c b/fs/exec.c
index 547a2390baf5..aee36e5733ce 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -64,6 +64,7 @@
 #include <linux/compat.h>
 #include <linux/vmalloc.h>
 #include <linux/io_uring.h>
+#include <linux/syscall_user_dispatch.h>
 
 #include <linux/uaccess.h>
 #include <asm/mmu_context.h>
@@ -1302,6 +1303,8 @@ int begin_new_exec(struct linux_binprm * bprm)
 	flush_thread();
 	me->personality &= ~bprm->per_clear;
 
+	clear_syscall_work_syscall_user_dispatch(me);
+
 	/*
 	 * We have to apply CLOEXEC before we change whether the process is
 	 * dumpable (in setup_new_exec) to avoid a race with a process in userspace
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ee2fdf34095b..4b719dc2eba2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -34,6 +34,7 @@
 #include <linux/rseq.h>
 #include <linux/seqlock.h>
 #include <linux/kcsan.h>
+#include <linux/syscall_user_dispatch.h>
 #include <asm/kmap_size.h>
 
 /* task_struct member predeclarations (sorted alphabetically): */
@@ -1000,6 +1001,7 @@ struct task_struct {
 	unsigned int			sessionid;
 #endif
 	struct seccomp			seccomp;
+	struct syscall_user_dispatch	syscall_dispatch;
 
 	/* Thread group tracking: */
 	u64				parent_exec_id;
diff --git a/include/linux/syscall_user_dispatch.h b/include/linux/syscall_user_dispatch.h
new file mode 100644
index 000000000000..9517ea16f090
--- /dev/null
+++ b/include/linux/syscall_user_dispatch.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020 Collabora Ltd.
+ */
+#ifndef _SYSCALL_USER_DISPATCH_H
+#define _SYSCALL_USER_DISPATCH_H
+
+#include <linux/thread_info.h>
+
+#ifdef CONFIG_GENERIC_ENTRY
+
+struct syscall_user_dispatch {
+	char __user *selector;
+	unsigned long offset;
+	unsigned long len;
+	bool on_dispatch;
+};
+
+int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,
+			      unsigned long len, char __user *selector);
+
+#define clear_syscall_work_syscall_user_dispatch(tsk) \
+	clear_task_syscall_work(tsk, SYSCALL_USER_DISPATCH)
+
+#else
+struct syscall_user_dispatch {};
+
+static inline int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,
+					    unsigned long len, char __user *selector)
+{
+	return -EINVAL;
+}
+
+static inline void clear_syscall_work_syscall_user_dispatch(struct task_struct *tsk)
+{
+}
+
+#endif /* CONFIG_GENERIC_ENTRY */
+
+#endif /* _SYSCALL_USER_DISPATCH_H */
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index ca80a214df09..c8a974cead73 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -42,6 +42,7 @@ enum syscall_work_bit {
 	SYSCALL_WORK_BIT_SYSCALL_TRACE,
 	SYSCALL_WORK_BIT_SYSCALL_EMU,
 	SYSCALL_WORK_BIT_SYSCALL_AUDIT,
+	SYSCALL_WORK_BIT_SYSCALL_USER_DISPATCH,
 };
 
 #define SYSCALL_WORK_SECCOMP		BIT(SYSCALL_WORK_BIT_SECCOMP)
@@ -49,6 +50,7 @@ enum syscall_work_bit {
 #define SYSCALL_WORK_SYSCALL_TRACE	BIT(SYSCALL_WORK_BIT_SYSCALL_TRACE)
 #define SYSCALL_WORK_SYSCALL_EMU	BIT(SYSCALL_WORK_BIT_SYSCALL_EMU)
 #define SYSCALL_WORK_SYSCALL_AUDIT	BIT(SYSCALL_WORK_BIT_SYSCALL_AUDIT)
+#define SYSCALL_WORK_SYSCALL_USER_DISPATCH BIT(SYSCALL_WORK_BIT_SYSCALL_USER_DISPATCH)
 #endif
 
 #include <asm/thread_info.h>
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 7f0827705c9a..90deb41c8a34 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -247,4 +247,9 @@ struct prctl_mm_map {
 #define PR_SET_IO_FLUSHER		57
 #define PR_GET_IO_FLUSHER		58
 
+/* Dispatch syscalls to a userspace handler */
+#define PR_SET_SYSCALL_USER_DISPATCH	59
+# define PR_SYS_DISPATCH_OFF		0
+# define PR_SYS_DISPATCH_ON		1
+
 #endif /* _LINUX_PRCTL_H */
diff --git a/kernel/entry/Makefile b/kernel/entry/Makefile
index 34c8a3f1c735..095c775e001e 100644
--- a/kernel/entry/Makefile
+++ b/kernel/entry/Makefile
@@ -9,5 +9,5 @@ KCOV_INSTRUMENT := n
 CFLAGS_REMOVE_common.o	 = -fstack-protector -fstack-protector-strong
 CFLAGS_common.o		+= -fno-stack-protector
 
-obj-$(CONFIG_GENERIC_ENTRY) 		+= common.o
+obj-$(CONFIG_GENERIC_ENTRY) 		+= common.o syscall_user_dispatch.o
 obj-$(CONFIG_KVM_XFER_TO_GUEST_WORK)	+= kvm.o
diff --git a/kernel/entry/common.h b/kernel/entry/common.h
new file mode 100644
index 000000000000..cd0c4e5f143e
--- /dev/null
+++ b/kernel/entry/common.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _COMMON_H
+#define _COMMON_H
+
+bool do_syscall_user_dispatch(struct pt_regs *regs);
+
+static inline bool on_syscall_dispatch(void)
+{
+	if (unlikely(current->syscall_dispatch.on_dispatch)) {
+		current->syscall_dispatch.on_dispatch = false;
+		return true;
+	}
+	return false;
+}
+
+#endif
diff --git a/kernel/entry/syscall_user_dispatch.c b/kernel/entry/syscall_user_dispatch.c
new file mode 100644
index 000000000000..131c38a0b628
--- /dev/null
+++ b/kernel/entry/syscall_user_dispatch.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Collabora Ltd.
+ */
+#include <linux/sched.h>
+#include <linux/prctl.h>
+#include <linux/syscall_user_dispatch.h>
+#include <linux/uaccess.h>
+#include <linux/signal.h>
+#include <linux/elf.h>
+
+#include <asm/syscall.h>
+
+#include <linux/sched/signal.h>
+#include <linux/sched/task_stack.h>
+
+static void trigger_sigsys(struct pt_regs *regs)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = SIGSYS;
+	info.si_code = SYS_USER_DISPATCH;
+	info.si_call_addr = (void __user *)KSTK_EIP(current);
+	info.si_errno = 0;
+	info.si_arch = syscall_get_arch(current);
+	info.si_syscall = syscall_get_nr(current, regs);
+
+	force_sig_info(&info);
+}
+
+bool do_syscall_user_dispatch(struct pt_regs *regs)
+{
+	struct syscall_user_dispatch *sd = &current->syscall_dispatch;
+	char state;
+
+	if (likely(instruction_pointer(regs) - sd->offset < sd->len))
+		return false;
+
+	if (unlikely(arch_syscall_is_vdso_sigreturn(regs)))
+		return false;
+
+	if (likely(sd->selector)) {
+		/*
+		 * access_ok() is performed once, at prctl time, when
+		 * the selector is loaded by userspace.
+		 */
+		if (unlikely(__get_user(state, sd->selector)))
+			do_exit(SIGSEGV);
+
+		if (likely(state == PR_SYS_DISPATCH_OFF))
+			return false;
+
+		if (state != PR_SYS_DISPATCH_ON)
+			do_exit(SIGSYS);
+	}
+
+	sd->on_dispatch = true;
+	syscall_rollback(current, regs);
+	trigger_sigsys(regs);
+
+	return true;
+}
+
+int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,
+			      unsigned long len, char __user *selector)
+{
+	switch (mode) {
+	case PR_SYS_DISPATCH_OFF:
+		if (offset || len || selector)
+			return -EINVAL;
+		break;
+	case PR_SYS_DISPATCH_ON:
+		/*
+		 * Validate the direct dispatcher region just for basic
+		 * sanity against overflow and a 0-sized dispatcher
+		 * region.  If the user is able to submit a syscall from
+		 * an address, that address is obviously valid.
+		 */
+		if (offset && offset + len <= offset)
+			return -EINVAL;
+
+		if (selector && !access_ok(selector, sizeof(*selector)))
+			return -EFAULT;
+
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	current->syscall_dispatch.selector = selector;
+	current->syscall_dispatch.offset = offset;
+	current->syscall_dispatch.len = len;
+	current->syscall_dispatch.on_dispatch = false;
+
+	if (mode == PR_SYS_DISPATCH_ON)
+		set_syscall_work(SYSCALL_USER_DISPATCH);
+	else
+		clear_syscall_work(SYSCALL_USER_DISPATCH);
+
+	return 0;
+}
diff --git a/kernel/fork.c b/kernel/fork.c
index 9a01b89ed05c..99c76dab31c1 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -906,6 +906,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 	clear_user_return_notifier(tsk);
 	clear_tsk_need_resched(tsk);
 	set_task_stack_end_magic(tsk);
+	clear_syscall_work_syscall_user_dispatch(tsk);
 
 #ifdef CONFIG_STACKPROTECTOR
 	tsk->stack_canary = get_random_canary();
diff --git a/kernel/sys.c b/kernel/sys.c
index a730c03ee607..51f00fe20e4d 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -42,6 +42,7 @@
 #include <linux/syscore_ops.h>
 #include <linux/version.h>
 #include <linux/ctype.h>
+#include <linux/syscall_user_dispatch.h>
 
 #include <linux/compat.h>
 #include <linux/syscalls.h>
@@ -2530,6 +2531,10 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 
 		error = (current->flags & PR_IO_FLUSHER) == PR_IO_FLUSHER;
 		break;
+	case PR_SET_SYSCALL_USER_DISPATCH:
+		error = set_syscall_user_dispatch(arg2, arg3, arg4,
+						  (char __user *) arg5);
+		break;
 	default:
 		error = -EINVAL;
 		break;
