diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 21c8072dce17..19eedd4af4cd 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -79,8 +79,8 @@ static inline void wait_for_interrupt(void)
 }
 
 struct device_node;
-int riscv_of_processor_hartid(struct device_node *node);
-int riscv_of_parent_hartid(struct device_node *node);
+int riscv_of_processor_hartid(struct device_node *node, unsigned long *hartid);
+int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid);
 
 extern void riscv_fill_hwcap(void);
 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 23170c933d73..d3443be7eedc 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -42,7 +42,7 @@ void arch_send_call_function_ipi_mask(struct cpumask *mask);
 /* Hook for the generic smp_call_function_single() routine. */
 void arch_send_call_function_single_ipi(int cpu);
 
-int riscv_hartid_to_cpuid(int hartid);
+int riscv_hartid_to_cpuid(unsigned long hartid);
 
 /* Set custom IPI operations */
 void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops);
@@ -70,7 +70,7 @@ static inline void show_ipi_stats(struct seq_file *p, int prec)
 {
 }
 
-static inline int riscv_hartid_to_cpuid(int hartid)
+static inline int riscv_hartid_to_cpuid(unsigned long hartid)
 {
 	if (hartid == boot_cpu_hartid)
 		return 0;
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index fba9e9f46a8c..022fd1861992 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -14,37 +14,36 @@
  * Returns the hart ID of the given device tree node, or -ENODEV if the node
  * isn't an enabled and valid RISC-V hart node.
  */
-int riscv_of_processor_hartid(struct device_node *node)
+int riscv_of_processor_hartid(struct device_node *node, unsigned long *hart)
 {
 	const char *isa;
-	u32 hart;
 
 	if (!of_device_is_compatible(node, "riscv")) {
 		pr_warn("Found incompatible CPU\n");
 		return -ENODEV;
 	}
 
-	hart = of_get_cpu_hwid(node, 0);
-	if (hart == ~0U) {
+	*hart = (unsigned long) of_get_cpu_hwid(node, 0);
+	if (*hart == ~0UL) {
 		pr_warn("Found CPU without hart ID\n");
 		return -ENODEV;
 	}
 
 	if (!of_device_is_available(node)) {
-		pr_info("CPU with hartid=%d is not available\n", hart);
+		pr_info("CPU with hartid=%lu is not available\n", *hart);
 		return -ENODEV;
 	}
 
 	if (of_property_read_string(node, "riscv,isa", &isa)) {
-		pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n", hart);
+		pr_warn("CPU with hartid=%lu has no \"riscv,isa\" property\n", *hart);
 		return -ENODEV;
 	}
 	if (isa[0] != 'r' || isa[1] != 'v') {
-		pr_warn("CPU with hartid=%d has an invalid ISA of \"%s\"\n", hart, isa);
+		pr_warn("CPU with hartid=%lu has an invalid ISA of \"%s\"\n", *hart, isa);
 		return -ENODEV;
 	}
 
-	return hart;
+	return 0;
 }
 
 /*
@@ -53,11 +52,16 @@ int riscv_of_processor_hartid(struct device_node *node)
  * To achieve this, we walk up the DT tree until we find an active
  * RISC-V core (HART) node and extract the cpuid from it.
  */
-int riscv_of_parent_hartid(struct device_node *node)
+int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid)
 {
+	int rc;
+
 	for (; node; node = node->parent) {
-		if (of_device_is_compatible(node, "riscv"))
-			return riscv_of_processor_hartid(node);
+		if (of_device_is_compatible(node, "riscv")) {
+			rc = riscv_of_processor_hartid(node, hartid);
+			if (!rc)
+				return 0;
+		}
 	}
 
 	return -1;
diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c
index 4f5a6f84e2a4..efa0f0816634 100644
--- a/arch/riscv/kernel/cpu_ops_sbi.c
+++ b/arch/riscv/kernel/cpu_ops_sbi.c
@@ -65,7 +65,7 @@ static int sbi_hsm_hart_get_status(unsigned long hartid)
 static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle)
 {
 	unsigned long boot_addr = __pa_symbol(secondary_start_sbi);
-	int hartid = cpuid_to_hartid_map(cpuid);
+	unsigned long hartid = cpuid_to_hartid_map(cpuid);
 	unsigned long hsm_data;
 	struct sbi_hart_boot_data *bdata = &per_cpu(boot_data, cpuid);
 
@@ -107,7 +107,7 @@ static void sbi_cpu_stop(void)
 static int sbi_cpu_is_stopped(unsigned int cpuid)
 {
 	int rc;
-	int hartid = cpuid_to_hartid_map(cpuid);
+	unsigned long hartid = cpuid_to_hartid_map(cpuid);
 
 	rc = sbi_hsm_hart_get_status(hartid);
 
diff --git a/arch/riscv/kernel/cpu_ops_spinwait.c b/arch/riscv/kernel/cpu_ops_spinwait.c
index 346847f6c41c..3ade9152a3c7 100644
--- a/arch/riscv/kernel/cpu_ops_spinwait.c
+++ b/arch/riscv/kernel/cpu_ops_spinwait.c
@@ -18,7 +18,7 @@ void *__cpu_spinwait_task_pointer[NR_CPUS] __section(".data");
 static void cpu_update_secondary_bootdata(unsigned int cpuid,
 				   struct task_struct *tidle)
 {
-	int hartid = cpuid_to_hartid_map(cpuid);
+	unsigned long hartid = cpuid_to_hartid_map(cpuid);
 
 	/*
 	 * The hartid must be less than NR_CPUS to avoid out-of-bound access
@@ -27,7 +27,7 @@ static void cpu_update_secondary_bootdata(unsigned int cpuid,
 	 * spinwait booting is not the recommended approach for any platforms
 	 * booting Linux in S-mode and can be disabled in the future.
 	 */
-	if (hartid == INVALID_HARTID || hartid >= NR_CPUS)
+	if (hartid == INVALID_HARTID || hartid >= (unsigned long) NR_CPUS)
 		return;
 
 	/* Make sure tidle is updated */
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 1b3ec44e25f5..e233fe154c96 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -72,8 +72,9 @@ void __init riscv_fill_hwcap(void)
 	struct device_node *node;
 	const char *isa;
 	char print_str[NUM_ALPHA_EXTS + 1];
-	int i, j;
+	int i, j, rc;
 	static unsigned long isa2hwcap[256] = {0};
+	unsigned long hartid;
 
 	isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
 	isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M;
@@ -91,7 +92,8 @@ void __init riscv_fill_hwcap(void)
 		DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX);
 		const char *temp;
 
-		if (riscv_of_processor_hartid(node) < 0)
+		rc = riscv_of_processor_hartid(node, &hartid);
+		if (rc < 0)
 			continue;
 
 		if (of_property_read_string(node, "riscv,isa", &isa)) {
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index b5d30ea92292..018e7dc45df6 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -47,7 +47,7 @@ static struct {
 	unsigned long bits ____cacheline_aligned;
 } ipi_data[NR_CPUS] __cacheline_aligned;
 
-int riscv_hartid_to_cpuid(int hartid)
+int riscv_hartid_to_cpuid(unsigned long hartid)
 {
 	int i;
 
@@ -55,7 +55,7 @@ int riscv_hartid_to_cpuid(int hartid)
 		if (cpuid_to_hartid_map(i) == hartid)
 			return i;
 
-	pr_err("Couldn't find cpu id for hartid [%d]\n", hartid);
+	pr_err("Couldn't find cpu id for hartid [%lu]\n", hartid);
 	return -ENOENT;
 }
 
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index f1e4948a4b52..a752c7b41683 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -72,15 +72,16 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 void __init setup_smp(void)
 {
 	struct device_node *dn;
-	int hart;
+	unsigned long hart;
 	bool found_boot_cpu = false;
 	int cpuid = 1;
+	int rc;
 
 	cpu_set_ops(0);
 
 	for_each_of_cpu_node(dn) {
-		hart = riscv_of_processor_hartid(dn);
-		if (hart < 0)
+		rc = riscv_of_processor_hartid(dn, &hart);
+		if (rc < 0)
 			continue;
 
 		if (hart == cpuid_to_hartid_map(0)) {
@@ -90,7 +91,7 @@ void __init setup_smp(void)
 			continue;
 		}
 		if (cpuid >= NR_CPUS) {
-			pr_warn("Invalid cpuid [%d] for hartid [%d]\n",
+			pr_warn("Invalid cpuid [%d] for hartid [%lu]\n",
 				cpuid, hart);
 			continue;
 		}
diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 593d5a957b69..e460df7ed799 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -101,20 +101,21 @@ static irqreturn_t riscv_timer_interrupt(int irq, void *dev_id)
 
 static int __init riscv_timer_init_dt(struct device_node *n)
 {
-	int cpuid, hartid, error;
+	int cpuid, error;
+	unsigned long hartid;
 	struct device_node *child;
 	struct irq_domain *domain;
 
-	hartid = riscv_of_processor_hartid(n);
-	if (hartid < 0) {
-		pr_warn("Not valid hartid for node [%pOF] error = [%d]\n",
+	error = riscv_of_processor_hartid(n, &hartid);
+	if (error < 0) {
+		pr_warn("Not valid hartid for node [%pOF] error = [%lu]\n",
 			n, hartid);
-		return hartid;
+		return error;
 	}
 
 	cpuid = riscv_hartid_to_cpuid(hartid);
 	if (cpuid < 0) {
-		pr_warn("Invalid cpuid for hartid [%d]\n", hartid);
+		pr_warn("Invalid cpuid for hartid [%lu]\n", hartid);
 		return cpuid;
 	}
 
@@ -140,7 +141,7 @@ static int __init riscv_timer_init_dt(struct device_node *n)
 		return -ENODEV;
 	}
 
-	pr_info("%s: Registering clocksource cpuid [%d] hartid [%d]\n",
+	pr_info("%s: Registering clocksource cpuid [%d] hartid [%lu]\n",
 	       __func__, cpuid, hartid);
 	error = clocksource_register_hz(&riscv_clocksource, riscv_timebase);
 	if (error) {
diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c
index 9e85e58d1f27..b450ebf95977 100644
--- a/drivers/firmware/efi/libstub/riscv-stub.c
+++ b/drivers/firmware/efi/libstub/riscv-stub.c
@@ -8,6 +8,7 @@
 
 #include <asm/efi.h>
 #include <asm/sections.h>
+#include <asm/unaligned.h>
 
 #include "efistub.h"
 
@@ -29,7 +30,7 @@ static int get_boot_hartid_from_fdt(void)
 {
 	const void *fdt;
 	int chosen_node, len;
-	const fdt32_t *prop;
+	const void *prop;
 
 	fdt = get_efi_config_table(DEVICE_TREE_GUID);
 	if (!fdt)
@@ -40,10 +41,16 @@ static int get_boot_hartid_from_fdt(void)
 		return -EINVAL;
 
 	prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len);
-	if (!prop || len != sizeof(u32))
+	if (!prop)
+		return -EINVAL;
+
+	if (len == sizeof(u32))
+		hartid = (unsigned long) fdt32_to_cpu(*(fdt32_t *)prop);
+	else if (len == sizeof(u64))
+		hartid = (unsigned long) fdt64_to_cpu(__get_unaligned_t(fdt64_t, prop));
+	else
 		return -EINVAL;
 
-	hartid = fdt32_to_cpu(*prop);
 	return 0;
 }
 
diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
index b65bd8878d4f..499e5f81b3fe 100644
--- a/drivers/irqchip/irq-riscv-intc.c
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -95,10 +95,11 @@ static const struct irq_domain_ops riscv_intc_domain_ops = {
 static int __init riscv_intc_init(struct device_node *node,
 				  struct device_node *parent)
 {
-	int rc, hartid;
+	int rc;
+	unsigned long hartid;
 
-	hartid = riscv_of_parent_hartid(node);
-	if (hartid < 0) {
+	rc = riscv_of_parent_hartid(node, &hartid);
+	if (rc < 0) {
 		pr_warn("unable to find hart id for %pOF\n", node);
 		return 0;
 	}
diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index bb87e4c3b88e..4710d9741f36 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -317,7 +317,8 @@ static int __init plic_init(struct device_node *node,
 	for (i = 0; i < nr_contexts; i++) {
 		struct of_phandle_args parent;
 		irq_hw_number_t hwirq;
-		int cpu, hartid;
+		int cpu;
+		unsigned long hartid;
 
 		if (of_irq_parse_one(node, i, &parent)) {
 			pr_err("failed to parse parent for context %d.\n", i);
@@ -341,8 +342,8 @@ static int __init plic_init(struct device_node *node,
 			continue;
 		}
 
-		hartid = riscv_of_parent_hartid(parent.np);
-		if (hartid < 0) {
+		error = riscv_of_parent_hartid(parent.np, &hartid);
+		if (error < 0) {
 			pr_warn("failed to parse hart ID for context %d.\n", i);
 			continue;
 		}