diff --git a/hypervisor/arch/x86/cpu.c b/hypervisor/arch/x86/cpu.c
index 30a96e198..b0e4049f8 100644
--- a/hypervisor/arch/x86/cpu.c
+++ b/hypervisor/arch/x86/cpu.c
@@ -84,7 +84,7 @@ static void cpu_set_logical_id(uint32_t logical_id);
 static void print_hv_banner(void);
 int cpu_find_logical_id(uint32_t lapic_id);
 #ifndef CONFIG_EFI_STUB
-static void start_cpus();
+static void start_cpus(void);
 #endif
 static void pcpu_sync_sleep(unsigned long *sync, int mask_bit);
 int ibrs_type;
@@ -206,7 +206,7 @@ static int init_phy_cpu_storage(void)
 	 * allocate memory to save all lapic_id detected in parse_mdt.
 	 * We allocate 4K size which could save 4K CPUs lapic_id info.
 	 */
-	lapic_id_base = alloc_page(CPU_PAGE_SIZE);
+	lapic_id_base = alloc_page();
 	ASSERT(lapic_id_base != NULL, "fail to alloc page");
 
 	pcpu_num = parse_madt(lapic_id_base);
diff --git a/hypervisor/include/arch/x86/mmu.h b/hypervisor/include/arch/x86/mmu.h
index 1d9b3ac6c..08fbb6410 100644
--- a/hypervisor/include/arch/x86/mmu.h
+++ b/hypervisor/include/arch/x86/mmu.h
@@ -311,7 +311,7 @@ struct mem_io_node {
 };
 
 void *get_paging_pml4(void);
-void *alloc_paging_struct();
+void *alloc_paging_struct(void);
 void enable_paging(void *pml4_base_addr);
 void init_paging(void);
 void map_mem(struct map_params *map_params, void *paddr, void *vaddr,
diff --git a/hypervisor/include/lib/mem_mgt.h b/hypervisor/include/lib/mem_mgt.h
index 6c9807942..db20985da 100644
--- a/hypervisor/include/lib/mem_mgt.h
+++ b/hypervisor/include/lib/mem_mgt.h
@@ -48,7 +48,7 @@ struct mem_pool {
 /* APIs exposing memory allocation/deallocation abstractions */
 void *malloc(unsigned int num_bytes);
 void *calloc(unsigned int num_elements, unsigned int element_size);
-void *alloc_page();
+void *alloc_page(void);
 void *alloc_pages(unsigned int page_num);
 void free(void *ptr);