diff --git a/src/Makefile.housekeeping b/src/Makefile.housekeeping
index d13cb36..5d9c039 100644
--- a/src/Makefile.housekeeping
+++ b/src/Makefile.housekeeping
@@ -366,11 +366,6 @@
 include arch/$(ARCH)/Makefile
 endif
 
-# Include architecture-specific include path
-ifdef ARCH
-INCDIRS		+= arch/$(ARCH)/include
-endif
-
 ###############################################################################
 #
 # Especially ugly workarounds
diff --git a/src/arch/arm/Makefile b/src/arch/arm/Makefile
index b6509dd..f827ed4 100644
--- a/src/arch/arm/Makefile
+++ b/src/arch/arm/Makefile
@@ -3,9 +3,9 @@
 ASM_TCHAR	:= %
 ASM_TCHAR_OPS	:= %%
 
-# Include common ARM headers
+# Include ARM-specific headers
 #
-INCDIRS		+= arch/arm/include
+INCDIRS		:= arch/$(ARCH)/include arch/arm/include $(INCDIRS)
 
 # ARM-specific directories containing source files
 #
diff --git a/src/arch/arm/include/bits/acpi.h b/src/arch/arm/include/bits/acpi.h
deleted file mode 100644
index f9f2f00..0000000
--- a/src/arch/arm/include/bits/acpi.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_ACPI_H
-#define _BITS_ACPI_H
-
-/** @file
- *
- * ARM-specific ACPI API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_ACPI_H */
diff --git a/src/arch/arm/include/bits/hyperv.h b/src/arch/arm/include/bits/hyperv.h
deleted file mode 100644
index f0e0c87..0000000
--- a/src/arch/arm/include/bits/hyperv.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_HYPERV_H
-#define _BITS_HYPERV_H
-
-/** @file
- *
- * Hyper-V interface
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_HYPERV_H */
diff --git a/src/arch/arm/include/bits/iomap.h b/src/arch/arm/include/bits/iomap.h
deleted file mode 100644
index ae953c4..0000000
--- a/src/arch/arm/include/bits/iomap.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_IOMAP_H
-#define _BITS_IOMAP_H
-
-/** @file
- *
- * ARM-specific I/O mapping API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_IOMAP_H */
diff --git a/src/arch/arm/include/bits/mp.h b/src/arch/arm/include/bits/mp.h
deleted file mode 100644
index e7d4c0c..0000000
--- a/src/arch/arm/include/bits/mp.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_MP_H
-#define _BITS_MP_H
-
-/** @file
- *
- * ARM-specific multiprocessor API implementation
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_MP_H */
diff --git a/src/arch/arm/include/bits/pci_io.h b/src/arch/arm/include/bits/pci_io.h
deleted file mode 100644
index 91f507a..0000000
--- a/src/arch/arm/include/bits/pci_io.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_PCI_IO_H
-#define _BITS_PCI_IO_H
-
-/** @file
- *
- * ARM PCI I/O API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_PCI_IO_H */
diff --git a/src/arch/arm/include/bits/reboot.h b/src/arch/arm/include/bits/reboot.h
deleted file mode 100644
index 88c5025..0000000
--- a/src/arch/arm/include/bits/reboot.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_REBOOT_H
-#define _BITS_REBOOT_H
-
-/** @file
- *
- * ARM-specific reboot API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_REBOOT_H */
diff --git a/src/arch/arm/include/bits/sanboot.h b/src/arch/arm/include/bits/sanboot.h
deleted file mode 100644
index abd4c79..0000000
--- a/src/arch/arm/include/bits/sanboot.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_SANBOOT_H
-#define _BITS_SANBOOT_H
-
-/** @file
- *
- * ARM-specific sanboot API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_SANBOOT_H */
diff --git a/src/arch/arm/include/bits/smbios.h b/src/arch/arm/include/bits/smbios.h
deleted file mode 100644
index d942181..0000000
--- a/src/arch/arm/include/bits/smbios.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_SMBIOS_H
-#define _BITS_SMBIOS_H
-
-/** @file
- *
- * ARM-specific SMBIOS API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_SMBIOS_H */
diff --git a/src/arch/arm/include/bits/time.h b/src/arch/arm/include/bits/time.h
deleted file mode 100644
index 724d8b9..0000000
--- a/src/arch/arm/include/bits/time.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_TIME_H
-#define _BITS_TIME_H
-
-/** @file
- *
- * ARM-specific time API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_TIME_H */
diff --git a/src/arch/arm/include/bits/uaccess.h b/src/arch/arm/include/bits/uaccess.h
deleted file mode 100644
index 87f1150..0000000
--- a/src/arch/arm/include/bits/uaccess.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_UACCESS_H
-#define _BITS_UACCESS_H
-
-/** @file
- *
- * ARM-specific user access API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_UACCESS_H */
diff --git a/src/arch/arm/include/bits/uart.h b/src/arch/arm/include/bits/uart.h
deleted file mode 100644
index 6f85975..0000000
--- a/src/arch/arm/include/bits/uart.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_UART_H
-#define _BITS_UART_H
-
-/** @file
- *
- * 16550-compatible UART
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_UART_H */
diff --git a/src/arch/arm/include/bits/umalloc.h b/src/arch/arm/include/bits/umalloc.h
deleted file mode 100644
index 27970d7..0000000
--- a/src/arch/arm/include/bits/umalloc.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_UMALLOC_H
-#define _BITS_UMALLOC_H
-
-/** @file
- *
- * ARM-specific user memory allocation API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_UMALLOC_H */
diff --git a/src/arch/arm32/include/bits/tcpip.h b/src/arch/arm32/include/bits/tcpip.h
deleted file mode 100644
index fc3c5b3..0000000
--- a/src/arch/arm32/include/bits/tcpip.h
+++ /dev/null
@@ -1,19 +0,0 @@
-#ifndef _BITS_TCPIP_H
-#define _BITS_TCPIP_H
-
-/** @file
- *
- * Transport-network layer interface
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-static inline __attribute__ (( always_inline )) uint16_t
-tcpip_continue_chksum ( uint16_t partial, const void *data, size_t len ) {
-
-	/* Not yet optimised */
-	return generic_tcpip_continue_chksum ( partial, data, len );
-}
-
-#endif /* _BITS_TCPIP_H */
diff --git a/src/arch/loong64/Makefile b/src/arch/loong64/Makefile
index fd0bf13..90d0ec8 100644
--- a/src/arch/loong64/Makefile
+++ b/src/arch/loong64/Makefile
@@ -18,6 +18,9 @@
 # EFI requires -fshort-wchar, and nothing else currently uses wchar_t
 CFLAGS		+= -fshort-wchar
 
+# Include LoongArch64-specific headers
+INCDIRS		:= arch/$(ARCH)/include $(INCDIRS)
+
 # LoongArch64-specific directories containing source files
 SRCDIRS		+= arch/loong64/core
 SRCDIRS		+= arch/loong64/interface/efi
diff --git a/src/arch/loong64/include/bits/acpi.h b/src/arch/loong64/include/bits/acpi.h
deleted file mode 100644
index 83dd1df..0000000
--- a/src/arch/loong64/include/bits/acpi.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_ACPI_H
-#define _BITS_ACPI_H
-
-/** @file
- *
- * LoongArch64-specific ACPI API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_ACPI_H */
diff --git a/src/arch/loong64/include/bits/hyperv.h b/src/arch/loong64/include/bits/hyperv.h
deleted file mode 100644
index f0e0c87..0000000
--- a/src/arch/loong64/include/bits/hyperv.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_HYPERV_H
-#define _BITS_HYPERV_H
-
-/** @file
- *
- * Hyper-V interface
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_HYPERV_H */
diff --git a/src/arch/loong64/include/bits/iomap.h b/src/arch/loong64/include/bits/iomap.h
deleted file mode 100644
index 041171d..0000000
--- a/src/arch/loong64/include/bits/iomap.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_IOMAP_H
-#define _BITS_IOMAP_H
-
-/** @file
- *
- * LoongArch64-specific I/O mapping API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_IOMAP_H */
diff --git a/src/arch/loong64/include/bits/mp.h b/src/arch/loong64/include/bits/mp.h
deleted file mode 100644
index fef2fd5..0000000
--- a/src/arch/loong64/include/bits/mp.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_MP_H
-#define _BITS_MP_H
-
-/** @file
- *
- * LoongArch64-specific multiprocessor API implementation
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_MP_H */
diff --git a/src/arch/loong64/include/bits/pci_io.h b/src/arch/loong64/include/bits/pci_io.h
deleted file mode 100644
index fdc5141..0000000
--- a/src/arch/loong64/include/bits/pci_io.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_PCI_IO_H
-#define _BITS_PCI_IO_H
-
-/** @file
- *
- * LoongArch64-specific PCI I/O API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_PCI_IO_H */
diff --git a/src/arch/loong64/include/bits/reboot.h b/src/arch/loong64/include/bits/reboot.h
deleted file mode 100644
index 96a1eb1..0000000
--- a/src/arch/loong64/include/bits/reboot.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_REBOOT_H
-#define _BITS_REBOOT_H
-
-/** @file
- *
- * LoongArch64-specific reboot API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_REBOOT_H */
diff --git a/src/arch/loong64/include/bits/sanboot.h b/src/arch/loong64/include/bits/sanboot.h
deleted file mode 100644
index f9205e2..0000000
--- a/src/arch/loong64/include/bits/sanboot.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_SANBOOT_H
-#define _BITS_SANBOOT_H
-
-/** @file
- *
- * LoongArch64-specific sanboot API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_SANBOOT_H */
diff --git a/src/arch/loong64/include/bits/smbios.h b/src/arch/loong64/include/bits/smbios.h
deleted file mode 100644
index 6c87db4..0000000
--- a/src/arch/loong64/include/bits/smbios.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_SMBIOS_H
-#define _BITS_SMBIOS_H
-
-/** @file
- *
- * LoongArch64-specific SMBIOS API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_SMBIOS_H */
diff --git a/src/arch/loong64/include/bits/tcpip.h b/src/arch/loong64/include/bits/tcpip.h
deleted file mode 100644
index fc3c5b3..0000000
--- a/src/arch/loong64/include/bits/tcpip.h
+++ /dev/null
@@ -1,19 +0,0 @@
-#ifndef _BITS_TCPIP_H
-#define _BITS_TCPIP_H
-
-/** @file
- *
- * Transport-network layer interface
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-static inline __attribute__ (( always_inline )) uint16_t
-tcpip_continue_chksum ( uint16_t partial, const void *data, size_t len ) {
-
-	/* Not yet optimised */
-	return generic_tcpip_continue_chksum ( partial, data, len );
-}
-
-#endif /* _BITS_TCPIP_H */
diff --git a/src/arch/loong64/include/bits/time.h b/src/arch/loong64/include/bits/time.h
deleted file mode 100644
index 4cd7485..0000000
--- a/src/arch/loong64/include/bits/time.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_TIME_H
-#define _BITS_TIME_H
-
-/** @file
- *
- * LoongArch64-specific time API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_TIME_H */
diff --git a/src/arch/loong64/include/bits/uaccess.h b/src/arch/loong64/include/bits/uaccess.h
deleted file mode 100644
index dddd9be..0000000
--- a/src/arch/loong64/include/bits/uaccess.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_UACCESS_H
-#define _BITS_UACCESS_H
-
-/** @file
- *
- * LoongArch64-specific user access API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_UACCESS_H */
diff --git a/src/arch/loong64/include/bits/uart.h b/src/arch/loong64/include/bits/uart.h
deleted file mode 100644
index 6f85975..0000000
--- a/src/arch/loong64/include/bits/uart.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_UART_H
-#define _BITS_UART_H
-
-/** @file
- *
- * 16550-compatible UART
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_UART_H */
diff --git a/src/arch/loong64/include/bits/umalloc.h b/src/arch/loong64/include/bits/umalloc.h
deleted file mode 100644
index f6978b8..0000000
--- a/src/arch/loong64/include/bits/umalloc.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _BITS_UMALLOC_H
-#define _BITS_UMALLOC_H
-
-/** @file
- *
- * LoongArch64-specific user memory allocation API implementations
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#endif /* _BITS_UMALLOC_H */
diff --git a/src/arch/loong64/include/bits/xen.h b/src/arch/loong64/include/bits/xen.h
deleted file mode 100644
index 2a3d774..0000000
--- a/src/arch/loong64/include/bits/xen.h
+++ /dev/null
@@ -1,13 +0,0 @@
-#ifndef _BITS_XEN_H
-#define _BITS_XEN_H
-
-/** @file
- *
- * Xen interface
- *
- */
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#include <ipxe/nonxen.h>
-
-#endif /* _BITS_XEN_H */
diff --git a/src/arch/x86/Makefile b/src/arch/x86/Makefile
index ef80136..4a4d8ee 100644
--- a/src/arch/x86/Makefile
+++ b/src/arch/x86/Makefile
@@ -3,9 +3,9 @@
 ASM_TCHAR	:= @
 ASM_TCHAR_OPS	:= @
 
-# Include common x86 headers
+# Include x86-specific headers
 #
-INCDIRS		+= arch/x86/include
+INCDIRS		:= arch/$(ARCH)/include arch/x86/include $(INCDIRS)
 
 # x86-specific directories containing source files
 #
diff --git a/src/include/bits/acpi.h b/src/include/bits/acpi.h
new file mode 100644
index 0000000..d984205
--- /dev/null
+++ b/src/include/bits/acpi.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_ACPI_H
+#define _BITS_ACPI_H
+
+/** @file
+ *
+ * Dummy architecture-specific ACPI API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_ACPI_H */
diff --git a/src/include/bits/hyperv.h b/src/include/bits/hyperv.h
new file mode 100644
index 0000000..fd7ceee
--- /dev/null
+++ b/src/include/bits/hyperv.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_HYPERV_H
+#define _BITS_HYPERV_H
+
+/** @file
+ *
+ * Dummy architecture-specific Hyper-V interface
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_HYPERV_H */
diff --git a/src/include/bits/iomap.h b/src/include/bits/iomap.h
new file mode 100644
index 0000000..b3d8d0c
--- /dev/null
+++ b/src/include/bits/iomap.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_IOMAP_H
+#define _BITS_IOMAP_H
+
+/** @file
+ *
+ * Dummy architecture-specific I/O mapping API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_IOMAP_H */
diff --git a/src/include/bits/mp.h b/src/include/bits/mp.h
new file mode 100644
index 0000000..d7d2cdc
--- /dev/null
+++ b/src/include/bits/mp.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_MP_H
+#define _BITS_MP_H
+
+/** @file
+ *
+ * Dummy architecture-specific multiprocessor API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_MP_H */
diff --git a/src/include/bits/nap.h b/src/include/bits/nap.h
new file mode 100644
index 0000000..7b01f94
--- /dev/null
+++ b/src/include/bits/nap.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_NAP_H
+#define _BITS_NAP_H
+
+/** @file
+ *
+ * Dummy architecture-specific CPU sleeping API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_NAP_H */
diff --git a/src/include/bits/pci_io.h b/src/include/bits/pci_io.h
new file mode 100644
index 0000000..711449f
--- /dev/null
+++ b/src/include/bits/pci_io.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_PCI_IO_H
+#define _BITS_PCI_IO_H
+
+/** @file
+ *
+ * Dummy architecture-specific PCI I/O API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_PCI_IO_H */
diff --git a/src/include/bits/reboot.h b/src/include/bits/reboot.h
new file mode 100644
index 0000000..023647f
--- /dev/null
+++ b/src/include/bits/reboot.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_REBOOT_H
+#define _BITS_REBOOT_H
+
+/** @file
+ *
+ * Dummy architecture-specific reboot API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_REBOOT_H */
diff --git a/src/include/bits/sanboot.h b/src/include/bits/sanboot.h
new file mode 100644
index 0000000..addbb5b
--- /dev/null
+++ b/src/include/bits/sanboot.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_SANBOOT_H
+#define _BITS_SANBOOT_H
+
+/** @file
+ *
+ * Dummy architecture-specific sanboot API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_SANBOOT_H */
diff --git a/src/include/bits/smbios.h b/src/include/bits/smbios.h
new file mode 100644
index 0000000..3e06aad
--- /dev/null
+++ b/src/include/bits/smbios.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_SMBIOS_H
+#define _BITS_SMBIOS_H
+
+/** @file
+ *
+ * Dummy architecture-specific SMBIOS API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_SMBIOS_H */
diff --git a/src/include/bits/tcpip.h b/src/include/bits/tcpip.h
new file mode 100644
index 0000000..9cb54d4
--- /dev/null
+++ b/src/include/bits/tcpip.h
@@ -0,0 +1,32 @@
+#ifndef _BITS_TCPIP_H
+#define _BITS_TCPIP_H
+
+/** @file
+ *
+ * Generic architecture-specific transport-network layer interface
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+
+/**
+ * Calculate continued TCP/IP checkum
+ *
+ * @v partial		Checksum of already-summed data, in network byte order
+ * @v data		Data buffer
+ * @v len		Length of data buffer
+ * @ret cksum		Updated checksum, in network byte order
+ */
+static inline __attribute__ (( always_inline )) uint16_t
+tcpip_continue_chksum ( uint16_t partial, const void *data, size_t len ) {
+
+	/* Not yet optimised */
+	return generic_tcpip_continue_chksum ( partial, data, len );
+}
+
+#endif /* _BITS_TCPIP_H */
diff --git a/src/include/bits/time.h b/src/include/bits/time.h
new file mode 100644
index 0000000..aec9c2f
--- /dev/null
+++ b/src/include/bits/time.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_TIME_H
+#define _BITS_TIME_H
+
+/** @file
+ *
+ * Dummy architecture-specific time API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_TIME_H */
diff --git a/src/include/bits/uaccess.h b/src/include/bits/uaccess.h
new file mode 100644
index 0000000..09f5f46
--- /dev/null
+++ b/src/include/bits/uaccess.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_UACCESS_H
+#define _BITS_UACCESS_H
+
+/** @file
+ *
+ * Dummy architecture-specific user access API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_UACCESS_H */
diff --git a/src/include/bits/uart.h b/src/include/bits/uart.h
new file mode 100644
index 0000000..e132d5c
--- /dev/null
+++ b/src/include/bits/uart.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_UART_H
+#define _BITS_UART_H
+
+/** @file
+ *
+ * Dummy architecture-specific UART
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_UART_H */
diff --git a/src/include/bits/umalloc.h b/src/include/bits/umalloc.h
new file mode 100644
index 0000000..4927f0d
--- /dev/null
+++ b/src/include/bits/umalloc.h
@@ -0,0 +1,15 @@
+#ifndef _BITS_UMALLOC_H
+#define _BITS_UMALLOC_H
+
+/** @file
+ *
+ * Dummy architecture-specific user memory allocation API implementations
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_UMALLOC_H */
diff --git a/src/include/bits/xen.h b/src/include/bits/xen.h
new file mode 100644
index 0000000..7d0036b
--- /dev/null
+++ b/src/include/bits/xen.h
@@ -0,0 +1,16 @@
+#ifndef _BITS_XEN_H
+#define _BITS_XEN_H
+
+/** @file
+ *
+ * Dummy architecture-specific Xen interface
+ *
+ * This file is included only if the architecture does not provide its
+ * own version of this file.
+ *
+ */
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/nonxen.h>
+
+#endif /* _BITS_XEN_H */