diff --git a/arch/arm64/include/asm/rsi.h b/arch/arm64/include/asm/rsi.h
new file mode 100644
index 000000000000..3b56aac5dc43
--- /dev/null
+++ b/arch/arm64/include/asm/rsi.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#ifndef __ASM_RSI_H_
+#define __ASM_RSI_H_
+
+#include <linux/jump_label.h>
+#include <asm/rsi_cmds.h>
+
+extern struct static_key_false rsi_present;
+
+void arm64_setup_memory(void);
+
+void __init arm64_rsi_init(void);
+static inline bool is_realm_world(void)
+{
+	return static_branch_unlikely(&rsi_present);
+}
+
+static inline void set_memory_range(phys_addr_t start, phys_addr_t end,
+				    enum ripas state)
+{
+	unsigned long ret;
+	phys_addr_t top;
+
+	while (start != end) {
+		ret = rsi_set_addr_range_state(start, end, state, &top);
+		BUG_ON(ret);
+		BUG_ON(top < start);
+		BUG_ON(top > end);
+		start = top;
+	}
+}
+
+static inline void set_memory_range_protected(phys_addr_t start, phys_addr_t end)
+{
+	set_memory_range(start, end, RSI_RIPAS_RAM);
+}
+
+static inline void set_memory_range_shared(phys_addr_t start, phys_addr_t end)
+{
+	set_memory_range(start, end, RSI_RIPAS_EMPTY);
+}
+#endif
diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h
index a0b3c1bd786a..ee0df00efd87 100644
--- a/arch/arm64/include/asm/rsi_cmds.h
+++ b/arch/arm64/include/asm/rsi_cmds.h
@@ -48,10 +48,16 @@ static inline void invoke_rsi_fn_smc_with_res(unsigned long function_id,
 
 static inline unsigned long rsi_set_addr_range_state(phys_addr_t start,
 						     phys_addr_t end,
-						     enum ripas state)
+						     enum ripas state,
+						     phys_addr_t *top)
 {
-	return invoke_rsi_fn_smc(SMC_RSI_IPA_STATE_SET,
-				 start, (end - start), state, 0);
+	struct arm_smccc_res res;
+
+	invoke_rsi_fn_smc_with_res(SMC_RSI_IPA_STATE_SET,
+				   start, (end - start), state, 0, &res);
+
+	*top = res.a1;
+	return res.a0;
 }
 
 #endif
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index ceba6792f5b3..f301c2ad2fa7 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -34,7 +34,7 @@ obj-y			:= debug-monitors.o entry.o irq.o fpsimd.o		\
 			   cpufeature.o alternative.o cacheinfo.o		\
 			   smp.o smp_spin_table.o topology.o smccc-call.o	\
 			   syscall.o proton-pack.o idreg-override.o idle.o	\
-			   patching.o
+			   patching.o rsi.o
 
 obj-$(CONFIG_COMPAT)			+= sys32.o signal32.o			\
 					   sys_compat.o
diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
new file mode 100644
index 000000000000..b354ac661c9d
--- /dev/null
+++ b/arch/arm64/kernel/rsi.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#include <linux/jump_label.h>
+#include <linux/memblock.h>
+#include <asm/rsi.h>
+
+DEFINE_STATIC_KEY_FALSE_RO(rsi_present);
+
+static bool rsi_version_matches(void)
+{
+	unsigned long ver = rsi_get_version();
+
+	if (ver == SMCCC_RET_NOT_SUPPORTED)
+		return false;
+
+	pr_info("RME: RSI version %lu.%lu advertised\n",
+		RSI_ABI_VERSION_GET_MAJOR(ver),
+		RSI_ABI_VERSION_GET_MINOR(ver));
+
+	return (ver >= RSI_ABI_VERSION &&
+		RSI_ABI_VERSION_GET_MAJOR(ver) == RSI_ABI_VERSION_MAJOR);
+}
+
+void arm64_setup_memory(void)
+{
+	u64 i;
+	phys_addr_t start, end;
+
+	if (!static_branch_unlikely(&rsi_present))
+		return;
+
+	/*
+	 * Iterate over the available memory ranges
+	 * and convert the state to protected memory.
+	 */
+	for_each_mem_range(i, &start, &end) {
+		set_memory_range_protected(start, end);
+	}
+}
+
+void __init arm64_rsi_init(void)
+{
+	if (!rsi_version_matches())
+		return;
+
+	static_branch_enable(&rsi_present);
+}
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 12cfe9d0d3fa..ea89ee563135 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -43,6 +43,7 @@
 #include <asm/cpu_ops.h>
 #include <asm/kasan.h>
 #include <asm/numa.h>
+#include <asm/rsi.h>
 #include <asm/scs.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
@@ -312,6 +313,8 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
 	 * cpufeature code and early parameters.
 	 */
 	jump_label_init();
+	/* Init RSI after jump_labels are active */
+	arm64_rsi_init();
 	parse_early_param();
 
 	dynamic_scs_init();
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 58a0bb2c17f1..fa9088add624 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -39,6 +39,7 @@
 #include <asm/kvm_host.h>
 #include <asm/memory.h>
 #include <asm/numa.h>
+#include <asm/rsi.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <linux/sizes.h>
@@ -412,6 +413,7 @@ void __init arm64_memblock_init(void)
 		reserve_crashkernel();
 
 	high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
+	arm64_setup_memory();
 }
 
 void __init bootmem_init(void)
