diff --git a/ArmVirtPkg/CloudHvAcpiPlatformDxe/CloudHvAcpi.c b/ArmVirtPkg/CloudHvAcpiPlatformDxe/CloudHvAcpi.c
index 0595b0e1d3..254aa978c6 100644
--- a/ArmVirtPkg/CloudHvAcpiPlatformDxe/CloudHvAcpi.c
+++ b/ArmVirtPkg/CloudHvAcpiPlatformDxe/CloudHvAcpi.c
@@ -106,7 +106,7 @@ InstallCloudHvAcpiTables (
   } // while
 
   if (DsdtPtr == NULL) {
-    DEBUG ((DEBUG_ERROR, "%a: no DSDT found\n", __FUNCTION__));
+    DEBUG ((DEBUG_ERROR, "%a: no DSDT found\n", __func__));
     return EFI_NOT_FOUND;
   }
 
@@ -151,7 +151,7 @@ CloudHvAcpiPlatformEntryPoint (
     DEBUG ((
       DEBUG_ERROR,
       "%a: Fail to install Acpi table: %r\n",
-      __FUNCTION__,
+      __func__,
       Status
       ));
     CpuDeadLoop ();
diff --git a/ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.c b/ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.c
index 57bbfd20d0..cf9434e534 100644
--- a/ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.c
+++ b/ArmVirtPkg/Library/ArmVirtGicArchLib/ArmVirtGicArchLib.c
@@ -150,7 +150,7 @@ ArmVirtGicArchLibConstructor (
       break;
 
     default:
-      DEBUG ((DEBUG_ERROR, "%a: No GIC revision specified!\n", __FUNCTION__));
+      DEBUG ((DEBUG_ERROR, "%a: No GIC revision specified!\n", __func__));
       return RETURN_NOT_FOUND;
   }
 
diff --git a/ArmVirtPkg/Library/ArmVirtPL031FdtClientLib/ArmVirtPL031FdtClientLib.c b/ArmVirtPkg/Library/ArmVirtPL031FdtClientLib/ArmVirtPL031FdtClientLib.c
index 45dd9f179c..01bcd58d30 100644
--- a/ArmVirtPkg/Library/ArmVirtPL031FdtClientLib/ArmVirtPL031FdtClientLib.c
+++ b/ArmVirtPkg/Library/ArmVirtPL031FdtClientLib/ArmVirtPL031FdtClientLib.c
@@ -42,7 +42,7 @@ ArmVirtPL031FdtClientLibConstructor (
     DEBUG ((
       DEBUG_WARN,
       "%a: No 'arm,pl031' compatible DT node found\n",
-      __FUNCTION__
+      __func__
       ));
     return EFI_SUCCESS;
   }
@@ -58,7 +58,7 @@ ArmVirtPL031FdtClientLibConstructor (
     DEBUG ((
       DEBUG_WARN,
       "%a: No 'reg' property found in 'arm,pl031' compatible DT node\n",
-      __FUNCTION__
+      __func__
       ));
     return EFI_SUCCESS;
   }
diff --git a/ArmVirtPkg/Library/ArmVirtPsciResetSystemLib/ArmVirtPsciResetSystemLib.c b/ArmVirtPkg/Library/ArmVirtPsciResetSystemLib/ArmVirtPsciResetSystemLib.c
index c7065b7ec5..1f27b7648d 100644
--- a/ArmVirtPkg/Library/ArmVirtPsciResetSystemLib/ArmVirtPsciResetSystemLib.c
+++ b/ArmVirtPkg/Library/ArmVirtPsciResetSystemLib/ArmVirtPsciResetSystemLib.c
@@ -65,7 +65,7 @@ ArmPsciResetSystemLibConstructor (
     DEBUG ((
       DEBUG_ERROR,
       "%a: Unknown PSCI method \"%a\"\n",
-      __FUNCTION__,
+      __func__,
       Prop
       ));
     return EFI_NOT_FOUND;
@@ -105,7 +105,7 @@ ResetCold (
       break;
 
     default:
-      DEBUG ((DEBUG_ERROR, "%a: no PSCI method defined\n", __FUNCTION__));
+      DEBUG ((DEBUG_ERROR, "%a: no PSCI method defined\n", __func__));
   }
 }
 
@@ -154,7 +154,7 @@ ResetShutdown (
       break;
 
     default:
-      DEBUG ((DEBUG_ERROR, "%a: no PSCI method defined\n", __FUNCTION__));
+      DEBUG ((DEBUG_ERROR, "%a: no PSCI method defined\n", __func__));
   }
 }
 
diff --git a/ArmVirtPkg/Library/ArmVirtPsciResetSystemPeiLib/ArmVirtPsciResetSystemPeiLib.c b/ArmVirtPkg/Library/ArmVirtPsciResetSystemPeiLib/ArmVirtPsciResetSystemPeiLib.c
index 03d14fe432..dffc1fb979 100644
--- a/ArmVirtPkg/Library/ArmVirtPsciResetSystemPeiLib/ArmVirtPsciResetSystemPeiLib.c
+++ b/ArmVirtPkg/Library/ArmVirtPsciResetSystemPeiLib/ArmVirtPsciResetSystemPeiLib.c
@@ -73,7 +73,7 @@ DiscoverPsciMethod (
         DEBUG ((
           DEBUG_ERROR,
           "%a: Missing PSCI method property\n",
-          __FUNCTION__
+          __func__
           ));
         return PsciMethodUnknown;
       }
@@ -86,7 +86,7 @@ DiscoverPsciMethod (
         DEBUG ((
           DEBUG_ERROR,
           "%a: Unknown PSCI method \"%a\"\n",
-          __FUNCTION__,
+          __func__,
           Prop
           ));
         return PsciMethodUnknown;
@@ -119,7 +119,7 @@ PerformPsciAction (
       break;
 
     default:
-      DEBUG ((DEBUG_ERROR, "%a: no PSCI method defined\n", __FUNCTION__));
+      DEBUG ((DEBUG_ERROR, "%a: no PSCI method defined\n", __func__));
       ASSERT (FALSE);
   }
 }
diff --git a/ArmVirtPkg/Library/CloudHvVirtMemInfoLib/CloudHvVirtMemInfoLib.c b/ArmVirtPkg/Library/CloudHvVirtMemInfoLib/CloudHvVirtMemInfoLib.c
index 28a0c0b078..98cc138705 100644
--- a/ArmVirtPkg/Library/CloudHvVirtMemInfoLib/CloudHvVirtMemInfoLib.c
+++ b/ArmVirtPkg/Library/CloudHvVirtMemInfoLib/CloudHvVirtMemInfoLib.c
@@ -98,7 +98,7 @@ CloudHvVirtMemInfoPeiLibConstructor (
         DEBUG ((
           DEBUG_INFO,
           "%a: System RAM @ 0x%lx - 0x%lx\n",
-          __FUNCTION__,
+          __func__,
           CurBase,
           CurBase + CurSize - 1
           ));
@@ -124,7 +124,7 @@ CloudHvVirtMemInfoPeiLibConstructor (
           DEBUG ((
             DEBUG_WARN,
             "%a: memory node larger than %d will not be included into Memory System\n",
-            __FUNCTION__,
+            __func__,
             CLOUDHV_MAX_MEM_NODE_NUM
             ));
           break;
@@ -133,7 +133,7 @@ CloudHvVirtMemInfoPeiLibConstructor (
         DEBUG ((
           DEBUG_ERROR,
           "%a: Failed to parse FDT memory node\n",
-          __FUNCTION__
+          __func__
           ));
       }
     }
@@ -186,7 +186,7 @@ ArmVirtGetMemoryMap (
                          );
 
   if (VirtualMemoryTable == NULL) {
-    DEBUG ((DEBUG_ERROR, "%a: Error: Failed AllocatePool()\n", __FUNCTION__));
+    DEBUG ((DEBUG_ERROR, "%a: Error: Failed AllocatePool()\n", __func__));
     return;
   }
 
@@ -205,7 +205,7 @@ ArmVirtGetMemoryMap (
       "\tPhysicalBase: 0x%lX\n"
       "\tVirtualBase: 0x%lX\n"
       "\tLength: 0x%lX\n",
-      __FUNCTION__,
+      __func__,
       MemNodeIndex,
       VirtualMemoryTable[Index].PhysicalBase,
       VirtualMemoryTable[Index].VirtualBase,
diff --git a/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.c b/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.c
index 89eee757d1..e8d3576a71 100644
--- a/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.c
+++ b/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.c
@@ -147,7 +147,7 @@ KvmtoolRtcFdtClientLibConstructor (
     DEBUG ((
       DEBUG_ERROR,
       "%a: No 'motorola,mc146818' compatible DT node found\n",
-      __FUNCTION__
+      __func__
       ));
     return Status;
   }
@@ -163,7 +163,7 @@ KvmtoolRtcFdtClientLibConstructor (
     DEBUG ((
       DEBUG_ERROR,
       "%a: No 'reg' property found in 'motorola,mc146818' compatible DT node\n",
-      __FUNCTION__
+      __func__
       ));
     return Status;
   }
diff --git a/ArmVirtPkg/Library/KvmtoolVirtMemInfoLib/KvmtoolVirtMemInfoLib.c b/ArmVirtPkg/Library/KvmtoolVirtMemInfoLib/KvmtoolVirtMemInfoLib.c
index 29122856b6..79412897f2 100644
--- a/ArmVirtPkg/Library/KvmtoolVirtMemInfoLib/KvmtoolVirtMemInfoLib.c
+++ b/ArmVirtPkg/Library/KvmtoolVirtMemInfoLib/KvmtoolVirtMemInfoLib.c
@@ -54,7 +54,7 @@ ArmVirtGetMemoryMap (
     DEBUG ((
       DEBUG_ERROR,
       "%a: Error: Failed to Allocate Pages\n",
-      __FUNCTION__
+      __func__
       ));
     return;
   }
diff --git a/ArmVirtPkg/Library/NorFlashKvmtoolLib/NorFlashKvmtool.c b/ArmVirtPkg/Library/NorFlashKvmtoolLib/NorFlashKvmtool.c
index 129c16b711..43f5858644 100644
--- a/ArmVirtPkg/Library/NorFlashKvmtoolLib/NorFlashKvmtool.c
+++ b/ArmVirtPkg/Library/NorFlashKvmtoolLib/NorFlashKvmtool.c
@@ -265,7 +265,7 @@ NorFlashPlatformLibConstructor (
       DEBUG ((
         DEBUG_ERROR,
         "%a: GetNodeProperty ('label') failed (Status == %r)\n",
-        __FUNCTION__,
+        __func__,
         Status
         ));
     } else if (AsciiStrCmp (Label, LABEL_UEFI_VAR_STORE) == 0) {
@@ -284,7 +284,7 @@ NorFlashPlatformLibConstructor (
       DEBUG ((
         DEBUG_ERROR,
         "%a: GetNodeProperty () failed (Status == %r)\n",
-        __FUNCTION__,
+        __func__,
         Status
         ));
       continue;
diff --git a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c
index 55bce88bc8..d0fa7e5046 100644
--- a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c
+++ b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c
@@ -75,7 +75,7 @@ VirtNorFlashPlatformGetDevices (
       DEBUG ((
         DEBUG_ERROR,
         "%a: GetNodeProperty () failed (Status == %r)\n",
-        __FUNCTION__,
+        __func__,
         Status
         ));
       continue;
diff --git a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c
index 3ad1ecd9d2..10c815378c 100644
--- a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c
+++ b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c
@@ -190,7 +190,7 @@ FilterAndProcess (
     DEBUG ((
       DEBUG_VERBOSE,
       "%a: %g: %r\n",
-      __FUNCTION__,
+      __func__,
       ProtocolGuid,
       Status
       ));
@@ -261,7 +261,7 @@ IsPciDisplay (
                         &Pci
                         );
   if (EFI_ERROR (Status)) {
-    DEBUG ((DEBUG_ERROR, "%a: %s: %r\n", __FUNCTION__, ReportText, Status));
+    DEBUG ((DEBUG_ERROR, "%a: %s: %r\n", __func__, ReportText, Status));
     return FALSE;
   }
 
@@ -410,7 +410,7 @@ IsVirtioPciRng (
   return FALSE;
 
 PciError:
-  DEBUG ((DEBUG_ERROR, "%a: %s: %r\n", __FUNCTION__, ReportText, Status));
+  DEBUG ((DEBUG_ERROR, "%a: %s: %r\n", __func__, ReportText, Status));
   return FALSE;
 }
 
@@ -437,7 +437,7 @@ Connect (
   DEBUG ((
     EFI_ERROR (Status) ? DEBUG_ERROR : DEBUG_VERBOSE,
     "%a: %s: %r\n",
-    __FUNCTION__,
+    __func__,
     ReportText,
     Status
     ));
@@ -463,7 +463,7 @@ AddOutput (
     DEBUG ((
       DEBUG_ERROR,
       "%a: %s: handle %p: device path not found\n",
-      __FUNCTION__,
+      __func__,
       ReportText,
       Handle
       ));
@@ -475,7 +475,7 @@ AddOutput (
     DEBUG ((
       DEBUG_ERROR,
       "%a: %s: adding to ConOut: %r\n",
-      __FUNCTION__,
+      __func__,
       ReportText,
       Status
       ));
@@ -487,7 +487,7 @@ AddOutput (
     DEBUG ((
       DEBUG_ERROR,
       "%a: %s: adding to ErrOut: %r\n",
-      __FUNCTION__,
+      __func__,
       ReportText,
       Status
       ));
@@ -497,7 +497,7 @@ AddOutput (
   DEBUG ((
     DEBUG_VERBOSE,
     "%a: %s: added to ConOut and ErrOut\n",
-    __FUNCTION__,
+    __func__,
     ReportText
     ));
 }
@@ -698,7 +698,7 @@ RemoveStaleFvFileOptions (
     DEBUG ((
       EFI_ERROR (Status) ? DEBUG_WARN : DEBUG_VERBOSE,
       "%a: removing stale Boot#%04x %s: %r\n",
-      __FUNCTION__,
+      __func__,
       (UINT32)BootOptions[Index].OptionNumber,
       DevicePathString == NULL ? L"<unavailable>" : DevicePathString,
       Status
@@ -878,7 +878,7 @@ PlatformBootManagerBeforeConsole (
   DEBUG ((
     EFI_ERROR (Status) ? DEBUG_ERROR : DEBUG_VERBOSE,
     "%a: SetVariable(%s, %u): %r\n",
-    __FUNCTION__,
+    __func__,
     EFI_TIME_OUT_VARIABLE_NAME,
     FrontPageTimeout,
     Status
diff --git a/ArmVirtPkg/Library/PlatformBootManagerLib/QemuKernel.c b/ArmVirtPkg/Library/PlatformBootManagerLib/QemuKernel.c
index c66b7c7b21..7dc59ae14d 100644
--- a/ArmVirtPkg/Library/PlatformBootManagerLib/QemuKernel.c
+++ b/ArmVirtPkg/Library/PlatformBootManagerLib/QemuKernel.c
@@ -66,7 +66,7 @@ TryRunningQemuKernel (
     DEBUG ((
       DEBUG_ERROR,
       "%a: QemuStartKernelImage(): %r\n",
-      __FUNCTION__,
+      __func__,
       Status
       ));
   }
diff --git a/ArmVirtPkg/Library/PlatformPeiLib/PlatformPeiLib.c b/ArmVirtPkg/Library/PlatformPeiLib/PlatformPeiLib.c
index bb71fee649..8d9dcf504d 100644
--- a/ArmVirtPkg/Library/PlatformPeiLib/PlatformPeiLib.c
+++ b/ArmVirtPkg/Library/PlatformPeiLib/PlatformPeiLib.c
@@ -111,7 +111,7 @@ PlatformPeim (
 
         UartBase = fdt64_to_cpu (ReadUnaligned64 (RegProp));
 
-        DEBUG ((DEBUG_INFO, "%a: PL011 UART @ 0x%lx\n", __FUNCTION__, UartBase));
+        DEBUG ((DEBUG_INFO, "%a: PL011 UART @ 0x%lx\n", __func__, UartBase));
 
         *UartHobData = UartBase;
         break;
@@ -148,7 +148,7 @@ PlatformPeim (
               DEBUG ((
                 DEBUG_WARN,
                 "%a: 'ranges' property has unexpected size %d\n",
-                __FUNCTION__,
+                __func__,
                 RangesLen
                 ));
               break;
@@ -175,7 +175,7 @@ PlatformPeim (
 
   if (FeaturePcdGet (PcdTpm2SupportEnabled)) {
     if (TpmBase != 0) {
-      DEBUG ((DEBUG_INFO, "%a: TPM @ 0x%lx\n", __FUNCTION__, TpmBase));
+      DEBUG ((DEBUG_INFO, "%a: TPM @ 0x%lx\n", __func__, TpmBase));
 
       Status = (EFI_STATUS)PcdSet64S (PcdTpmBaseAddress, TpmBase);
       ASSERT_EFI_ERROR (Status);
diff --git a/ArmVirtPkg/Library/QemuVirtMemInfoLib/QemuVirtMemInfoLib.c b/ArmVirtPkg/Library/QemuVirtMemInfoLib/QemuVirtMemInfoLib.c
index 9cf43f06c0..23bd0fe68e 100644
--- a/ArmVirtPkg/Library/QemuVirtMemInfoLib/QemuVirtMemInfoLib.c
+++ b/ArmVirtPkg/Library/QemuVirtMemInfoLib/QemuVirtMemInfoLib.c
@@ -83,7 +83,7 @@ ArmVirtGetMemoryMap (
                          );
 
   if (VirtualMemoryTable == NULL) {
-    DEBUG ((DEBUG_ERROR, "%a: Error: Failed AllocatePool()\n", __FUNCTION__));
+    DEBUG ((DEBUG_ERROR, "%a: Error: Failed AllocatePool()\n", __func__));
     return;
   }
 
@@ -99,7 +99,7 @@ ArmVirtGetMemoryMap (
     "\tPhysicalBase: 0x%lX\n"
     "\tVirtualBase: 0x%lX\n"
     "\tLength: 0x%lX\n",
-    __FUNCTION__,
+    __func__,
     VirtualMemoryTable[0].PhysicalBase,
     VirtualMemoryTable[0].VirtualBase,
     VirtualMemoryTable[0].Length
diff --git a/ArmVirtPkg/Library/QemuVirtMemInfoLib/QemuVirtMemInfoPeiLibConstructor.c b/ArmVirtPkg/Library/QemuVirtMemInfoLib/QemuVirtMemInfoPeiLibConstructor.c
index c47ab82966..1bcc2e26aa 100644
--- a/ArmVirtPkg/Library/QemuVirtMemInfoLib/QemuVirtMemInfoPeiLibConstructor.c
+++ b/ArmVirtPkg/Library/QemuVirtMemInfoLib/QemuVirtMemInfoPeiLibConstructor.c
@@ -64,7 +64,7 @@ QemuVirtMemInfoPeiLibConstructor (
         DEBUG ((
           DEBUG_INFO,
           "%a: System RAM @ 0x%lx - 0x%lx\n",
-          __FUNCTION__,
+          __func__,
           CurBase,
           CurBase + CurSize - 1
           ));
@@ -77,7 +77,7 @@ QemuVirtMemInfoPeiLibConstructor (
         DEBUG ((
           DEBUG_ERROR,
           "%a: Failed to parse FDT memory node\n",
-          __FUNCTION__
+          __func__
           ));
       }
     }
diff --git a/ArmVirtPkg/XenAcpiPlatformDxe/XenAcpiPlatformDxe.c b/ArmVirtPkg/XenAcpiPlatformDxe/XenAcpiPlatformDxe.c
index 96bc442f69..32c8b1e94e 100644
--- a/ArmVirtPkg/XenAcpiPlatformDxe/XenAcpiPlatformDxe.c
+++ b/ArmVirtPkg/XenAcpiPlatformDxe/XenAcpiPlatformDxe.c
@@ -68,7 +68,7 @@ GetXenArmAcpiRsdp (
     DEBUG ((
       DEBUG_WARN,
       "%a: No 'xen,guest-acpi' compatible DT node found\n",
-      __FUNCTION__
+      __func__
       ));
     return EFI_NOT_FOUND;
   }
@@ -140,7 +140,7 @@ InstallXenArmTables (
   //
   Status = GetXenArmAcpiRsdp (&XenAcpiRsdpStructurePtr);
   if (EFI_ERROR (Status)) {
-    DEBUG ((DEBUG_INFO, "%a: No RSDP table found\n", __FUNCTION__));
+    DEBUG ((DEBUG_INFO, "%a: No RSDP table found\n", __func__));
     return Status;
   }
 
diff --git a/ArmVirtPkg/XenioFdtDxe/XenioFdtDxe.c b/ArmVirtPkg/XenioFdtDxe/XenioFdtDxe.c
index 23d504cc64..f626c455c4 100644
--- a/ArmVirtPkg/XenioFdtDxe/XenioFdtDxe.c
+++ b/ArmVirtPkg/XenioFdtDxe/XenioFdtDxe.c
@@ -49,7 +49,7 @@ InitializeXenioFdtDxe (
     DEBUG ((
       DEBUG_WARN,
       "%a: No 'xen,xen' compatible DT node found\n",
-      __FUNCTION__
+      __func__
       ));
     return EFI_UNSUPPORTED;
   }
@@ -70,7 +70,7 @@ InitializeXenioFdtDxe (
       DEBUG_ERROR,
       "%a: XenIoMmioInstall () failed on a new handle "
       "(Status == %r)\n",
-      __FUNCTION__,
+      __func__,
       Status
       ));
     return Status;