diff --git a/kernel/drivers/opensbi/extensions/legacy.cpp b/kernel/drivers/opensbi/extensions/legacy.cpp
index 728418a..c77c82b 100644
--- a/kernel/drivers/opensbi/extensions/legacy.cpp
+++ b/kernel/drivers/opensbi/extensions/legacy.cpp
@@ -15,18 +15,22 @@ namespace opensbi::legacy {
             REMOTE_SFENCE_VMA_ASID,
             SHUTDOWN
         };
+
+        enum class Functionid {
+            UNUSED
+        };
     }
 
     SbiRet set_timer(std::uint64_t stime_value) {
 #if __riscv_xlen == 64
         return ecall(
             static_cast<sbiword_t>(ExtensionId::SET_TIMER),
-            0,
+            static_cast<sbiword_t>(Functionid::UNUSED),
             stime_value);
 #else
         return ecall(
             static_cast<sbiword_t>(ExtensionId::SET_TIMER),
-            0,
+            static_cast<sbiword_t>(Functionid::UNUSED),
             static_cast<uint32_t>(stime_value),
             static_cast<uint32_t>(stime_value >> 32));
 #endif
@@ -35,33 +39,33 @@ namespace opensbi::legacy {
     SbiRet console_putchar(int ch) {
         return ecall(
             static_cast<sbiword_t>(ExtensionId::CONSOLE_PUTCHAR),
-            0,
+            static_cast<sbiword_t>(Functionid::UNUSED),
             ch);
     }
 
     SbiRet console_getchar() {
         return ecall(
             static_cast<sbiword_t>(ExtensionId::CONSOLE_GETCHAR),
-            0);
+            static_cast<sbiword_t>(Functionid::UNUSED));
     }
 
     SbiRet clear_ipmi() {
         return ecall(
             static_cast<sbiword_t>(ExtensionId::CLEAR_IPI),
-            0);
+            static_cast<sbiword_t>(Functionid::UNUSED));
     }
 
     SbiRet send_ipmi(hart_mask_t hart_mask) {
         return ecall(
             static_cast<sbiword_t>(ExtensionId::SEND_IPI),
-            0,
+            static_cast<sbiword_t>(Functionid::UNUSED),
             reinterpret_cast<sbiword_t>(hart_mask));
     }
 
     SbiRet remote_fence_i(hart_mask_t hart_mask) {
         return ecall(
             static_cast<sbiword_t>(ExtensionId::REMOTE_FENCE_I),
-            0,
+            static_cast<sbiword_t>(Functionid::UNUSED),
             reinterpret_cast<sbiword_t>(hart_mask));
     }
 
@@ -71,7 +75,7 @@ namespace opensbi::legacy {
             sbiword_t size) {
         return ecall(
             static_cast<sbiword_t>(ExtensionId::REMOTE_SFENCE_VMA),
-            0,
+            static_cast<sbiword_t>(Functionid::UNUSED),
             reinterpret_cast<sbiword_t>(hart_mask),
             start,
             size);
@@ -84,7 +88,7 @@ namespace opensbi::legacy {
             sbiword_t asid) {
         return ecall(
             static_cast<sbiword_t>(ExtensionId::REMOTE_SFENCE_VMA_ASID),
-            0,
+            static_cast<sbiword_t>(Functionid::UNUSED),
             reinterpret_cast<sbiword_t>(hart_mask),
             start,
             size,
@@ -94,7 +98,7 @@ namespace opensbi::legacy {
     void shutdown() {
         ecall(
             static_cast<sbiword_t>(ExtensionId::SHUTDOWN),
-            0);
+            static_cast<sbiword_t>(Functionid::UNUSED));
 
         // This should never be reached, explode if it is
         __builtin_trap();