diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index ecba671..da8f74a 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -51,11 +51,13 @@ static inline bool acpi_has_cpu_in_madt(void)
 }
 
 static inline void arch_fix_phys_package_id(int num, u32 slot) { }
+void __init acpi_smp_init_cpus(void);
 
 #else
 
 static inline bool acpi_psci_present(void) { return false; }
 static inline bool acpi_psci_use_hvc(void) { return false; }
+static inline void acpi_smp_init_cpus(void) { }
 
 #endif /* CONFIG_ACPI */
 
diff --git a/arch/arm64/include/asm/cpu_ops.h b/arch/arm64/include/asm/cpu_ops.h
index d7b4b38..d149580 100644
--- a/arch/arm64/include/asm/cpu_ops.h
+++ b/arch/arm64/include/asm/cpu_ops.h
@@ -61,6 +61,7 @@ struct cpu_operations {
 };
 
 extern const struct cpu_operations *cpu_ops[NR_CPUS];
+const struct cpu_operations *cpu_get_ops(const char *name);
 extern int __init cpu_read_ops(struct device_node *dn, int cpu);
 extern void __init cpu_read_bootcpu_ops(void);
 
diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h
index a498f2c..c877adc 100644
--- a/arch/arm64/include/asm/smp.h
+++ b/arch/arm64/include/asm/smp.h
@@ -39,9 +39,10 @@ extern void show_ipi_list(struct seq_file *p, int prec);
 extern void handle_IPI(int ipinr, struct pt_regs *regs);
 
 /*
- * Setup the set of possible CPUs (via set_cpu_possible)
+ * Discover the set of possible CPUs and determine their
+ * SMP operations.
  */
-extern void smp_init_cpus(void);
+extern void of_smp_init_cpus(void);
 
 /*
  * Provide a function to raise an IPI cross call on CPUs in callmap.
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 9e1ae37..644b8b8 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -24,6 +24,10 @@
 #include <linux/bootmem.h>
 #include <linux/smp.h>
 
+#include <asm/smp_plat.h>
+#include <asm/cputype.h>
+#include <asm/cpu_ops.h>
+
 int acpi_noirq;			/* skip ACPI IRQ initialization */
 int acpi_disabled;
 EXPORT_SYMBOL(acpi_disabled);
@@ -31,6 +35,8 @@ EXPORT_SYMBOL(acpi_disabled);
 int acpi_pci_disabled;		/* skip ACPI PCI scan and IRQ initialization */
 EXPORT_SYMBOL(acpi_pci_disabled);
 
+static int enabled_cpus;	/* Processors (GICC) with enabled flag in MADT */
+
 /*
  * __acpi_map_table() will be called before page_init(), so early_ioremap()
  * or early_memremap() should be called here to for ACPI table mapping.
@@ -51,6 +57,131 @@ void __init __acpi_unmap_table(char *map, unsigned long size)
 	early_memunmap(map, size);
 }
 
+/**
+ * acpi_map_gic_cpu_interface - generates a logical cpu number
+ * and map to MPIDR represented by GICC structure
+ * @mpidr: CPU's hardware id to register, MPIDR represented in MADT
+ * @enabled: this cpu is enabled or not
+ *
+ * Returns the logical cpu number which maps to MPIDR
+ */
+static int acpi_map_gic_cpu_interface(u64 mpidr, u8 enabled)
+{
+	int cpu;
+
+	if (mpidr == INVALID_HWID) {
+		pr_info("Skip invalid cpu hardware ID\n");
+		return -EINVAL;
+	}
+
+	total_cpus++;
+	if (!enabled)
+		return -EINVAL;
+
+	if (enabled_cpus >=  NR_CPUS) {
+		pr_warn("NR_CPUS limit of %d reached, Processor %d/0x%llx ignored.\n",
+			NR_CPUS, total_cpus, mpidr);
+		return -EINVAL;
+	}
+
+	/* No need to check duplicate MPIDRs for the first CPU */
+	if (enabled_cpus) {
+		/*
+		 * Duplicate MPIDRs are a recipe for disaster. Scan
+		 * all initialized entries and check for
+		 * duplicates. If any is found just ignore the CPU.
+		 */
+		for_each_possible_cpu(cpu) {
+			if (cpu_logical_map(cpu) == mpidr) {
+				pr_err("Firmware bug, duplicate CPU MPIDR: 0x%llx in MADT\n",
+				mpidr);
+				return -EINVAL;
+			}
+		}
+		
+		/* allocate a logical cpu id for the new comer */
+		cpu = cpumask_next_zero(-1, cpu_possible_mask);
+	} else {
+		/* First GICC entry must be BSP as ACPI spec said */
+		if  (cpu_logical_map(0) != mpidr) {
+			pr_err("First GICC entry with MPIDR 0x%llx is not BSP\n",
+			       mpidr);
+			return -EINVAL;
+		}
+
+		/*
+		 * boot_cpu_init() already hold bit 0 in cpu_present_mask
+		 * for BSP, no need to allocate again.
+		 */
+		cpu = 0;
+	}
+
+	/* CPU 0 was already initialized */
+	if (cpu) {
+		cpu_ops[cpu] = cpu_get_ops(acpi_psci_present() ? "psci" : NULL);
+		if (!cpu_ops[cpu])
+			return -EINVAL;
+
+		if (cpu_ops[cpu]->cpu_init(NULL, cpu))
+			return -EOPNOTSUPP;
+
+		/* map the logical cpu id to cpu MPIDR */
+		cpu_logical_map(cpu) = mpidr;
+
+		set_cpu_possible(cpu, true);
+	} else {
+		/* get cpu0's ops, no need to return if ops is null */
+		cpu_ops[0] = cpu_get_ops(acpi_psci_present() ? "psci" : NULL);
+	}
+
+	enabled_cpus++;
+	return cpu;
+}
+
+static int __init
+acpi_parse_gic_cpu_interface(struct acpi_subtable_header *header,
+				const unsigned long end)
+{
+	struct acpi_madt_generic_interrupt *processor;
+
+	processor = (struct acpi_madt_generic_interrupt *)header;
+
+	if (BAD_MADT_ENTRY(processor, end))
+		return -EINVAL;
+
+	acpi_table_print_madt_entry(header);
+
+	acpi_map_gic_cpu_interface(processor->arm_mpidr & MPIDR_HWID_BITMASK,
+		processor->flags & ACPI_MADT_ENABLED);
+
+	return 0;
+}
+
+/* Parse GIC cpu interface entries in MADT for SMP init */
+void __init acpi_smp_init_cpus(void)
+{
+	int count;
+
+	/*
+	 * do a partial walk of MADT to determine how many CPUs
+	 * we have including disabled CPUs, and get information
+	 * we need for SMP init
+	 */
+	count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
+			acpi_parse_gic_cpu_interface, 0);
+
+	if (!count) {
+		pr_err("No GIC CPU interface entries present\n");
+		return;
+	} else if (count < 0) {
+		pr_err("Error parsing GIC CPU interface entry\n");
+		return;
+	}
+
+	/* Make boot-up look pretty */
+	pr_info("%d CPUs enabled, %d CPUs total\n", enabled_cpus, total_cpus);
+}
+
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
 	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
@@ -62,8 +193,20 @@ static int __init acpi_parse_fadt(struct acpi_table_header *table)
 	 * to get arm boot flags, or we will disable ACPI.
 	 */
 	if (table->revision > 5 ||
-	    (table->revision == 5 && fadt->minor_revision >= 1))
-		return 0;
+	    (table->revision == 5 && fadt->minor_revision >= 1)) {
+		/*
+		 * ACPI 5.1 only has two explicit methods to boot up SMP,
+		 * PSCI and Parking protocol, but the Parking protocol is
+		 * only specified for ARMv7 now, so make PSCI as the only
+		 * way for the SMP boot protocol before some updates for
+		 * the ACPI spec or the Parking protocol spec.
+		 */
+		if (acpi_psci_present())
+			return 0;
+
+		pr_warn("has no PSCI support, will not bring up secondary CPUs\n");
+		return -EOPNOTSUPP;
+	}
 
 	pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n",
 		table->revision, fadt->minor_revision);
diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
index cce9524..1a04deb 100644
--- a/arch/arm64/kernel/cpu_ops.c
+++ b/arch/arm64/kernel/cpu_ops.c
@@ -27,7 +27,7 @@ extern const struct cpu_operations cpu_psci_ops;
 
 const struct cpu_operations *cpu_ops[NR_CPUS];
 
-static const struct cpu_operations *supported_cpu_ops[] __initconst = {
+static const struct cpu_operations *supported_cpu_ops[] = {
 #ifdef CONFIG_SMP
 	&smp_spin_table_ops,
 #endif
@@ -35,7 +35,7 @@ static const struct cpu_operations *supported_cpu_ops[] __initconst = {
 	NULL,
 };
 
-static const struct cpu_operations * __init cpu_get_ops(const char *name)
+const struct cpu_operations *cpu_get_ops(const char *name)
 {
 	const struct cpu_operations **ops = supported_cpu_ops;
 
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 7ba20d4..281fa34 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -60,6 +60,7 @@
 #include <asm/memblock.h>
 #include <asm/psci.h>
 #include <asm/efi.h>
+#include <asm/acpi.h>
 
 unsigned int processor_id;
 EXPORT_SYMBOL(processor_id);
@@ -401,13 +402,16 @@ void __init setup_arch(char **cmdline_p)
 	if (acpi_disabled) {
 		unflatten_device_tree();
 		psci_dt_init();
+		cpu_read_bootcpu_ops();
+#ifdef CONFIG_SMP
+		of_smp_init_cpus();
+#endif
 	} else {
 		psci_acpi_init();
+		acpi_smp_init_cpus();
 	}
 
-	cpu_read_bootcpu_ops();
 #ifdef CONFIG_SMP
-	smp_init_cpus();
 	smp_build_mpidr_hash();
 #endif
 
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 4743397..4e390ac 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -321,7 +321,7 @@ void __init smp_prepare_boot_cpu(void)
  * cpu logical map array containing MPIDR values related to logical
  * cpus. Assumes that cpu_logical_map(0) has already been initialized.
  */
-void __init smp_init_cpus(void)
+void __init of_smp_init_cpus(void)
 {
 	struct device_node *dn = NULL;
 	unsigned int i, cpu = 1;
