[arm] Add support for 32-bit ARM

Signed-off-by: Michael Brown <mcb30@ipxe.org>

43 files changed, 1879 insertions, 49 deletions

diff --git a/src/arch/arm/Makefile b/src/arch/arm/Makefile
new file mode 100644
index 00000000..f883a64d
--- /dev/null
+++ b/src/arch/arm/Makefile
@@ -0,0 +1,25 @@
+# Assembler section type character
+#
+ASM_TCHAR	:= %
+ASM_TCHAR_OPS	:= %%
+
+# ARM-specific directories containing source files
+#
+SRCDIRS		+= arch/arm/core
+SRCDIRS		+= arch/arm/libgcc
+SRCDIRS		+= arch/arm/interface/efi
+
+# ARM-specific flags
+#
+CFLAGS		+= -mthumb -mcpu=cortex-a15 -mabi=aapcs -mfloat-abi=soft
+CFLAGS		+= -mword-relocations
+ASFLAGS		+= -mthumb -mcpu=cortex-a15
+
+# EFI requires -fshort-wchar, and nothing else currently uses wchar_t
+#
+CFLAGS		+= -fshort-wchar
+
+# Include platform-specific Makefile
+#
+MAKEDEPS	+= arch/arm/Makefile.$(PLATFORM)
+include arch/arm/Makefile.$(PLATFORM)
diff --git a/src/arch/arm/Makefile.efi b/src/arch/arm/Makefile.efi
new file mode 100644
index 00000000..909c8d21
--- /dev/null
+++ b/src/arch/arm/Makefile.efi
@@ -0,0 +1,14 @@
+# -*- makefile -*- : Force emacs to use Makefile mode
+
+# Specify EFI image builder
+#
+ELF2EFI		= $(ELF2EFI32)
+
+# Specify EFI boot file
+#
+EFI_BOOT_FILE	= bootarm.efi
+
+# Include generic EFI Makefile
+#
+MAKEDEPS	+= Makefile.efi
+include Makefile.efi
diff --git a/src/arch/arm/core/arm_bigint.c b/src/arch/arm/core/arm_bigint.c
new file mode 100644
index 00000000..839bead1
--- /dev/null
+++ b/src/arch/arm/core/arm_bigint.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+#include <string.h>
+#include <ipxe/bigint.h>
+
+/** @file
+ *
+ * Big integer support
+ */
+
+/**
+ * Multiply big integers
+ *
+ * @v multiplicand0	Element 0 of big integer to be multiplied
+ * @v multiplier0	Element 0 of big integer to be multiplied
+ * @v result0		Element 0 of big integer to hold result
+ * @v size		Number of elements
+ */
+void bigint_multiply_raw ( const uint32_t *multiplicand0,
+			   const uint32_t *multiplier0,
+			   uint32_t *result0, unsigned int size ) {
+	const bigint_t ( size ) __attribute__ (( may_alias )) *multiplicand =
+		( ( const void * ) multiplicand0 );
+	const bigint_t ( size ) __attribute__ (( may_alias )) *multiplier =
+		( ( const void * ) multiplier0 );
+	bigint_t ( size * 2 ) __attribute__ (( may_alias )) *result =
+		( ( void * ) result0 );
+	unsigned int i;
+	unsigned int j;
+	uint32_t multiplicand_element;
+	uint32_t multiplier_element;
+	uint32_t *result_elements;
+	uint32_t discard_low;
+	uint32_t discard_high;
+	uint32_t discard_temp;
+
+	/* Zero result */
+	memset ( result, 0, sizeof ( *result ) );
+
+	/* Multiply integers one element at a time */
+	for ( i = 0 ; i < size ; i++ ) {
+		multiplicand_element = multiplicand->element[i];
+		for ( j = 0 ; j < size ; j++ ) {
+			multiplier_element = multiplier->element[j];
+			result_elements = &result->element[ i + j ];
+			/* Perform a single multiply, and add the
+			 * resulting double-element into the result,
+			 * carrying as necessary.  The carry can
+			 * never overflow beyond the end of the
+			 * result, since:
+			 *
+			 *     a < 2^{n}, b < 2^{n} => ab < 2^{2n}
+			 */
+			__asm__ __volatile__ ( "umull %1, %2, %5, %6\n\t"
+					       "ldr %3, [%0]\n\t"
+					       "adds %3, %1\n\t"
+					       "stmia %0!, {%3}\n\t"
+					       "ldr %3, [%0]\n\t"
+					       "adcs %3, %2\n\t"
+					       "stmia %0!, {%3}\n\t"
+					       "bcc 2f\n\t"
+					       "\n1:\n\t"
+					       "ldr %3, [%0]\n\t"
+					       "adcs %3, #0\n\t"
+					       "stmia %0!, {%3}\n\t"
+					       "bcs 1b\n\t"
+					       "\n2:\n\t"
+					       : "+l" ( result_elements ),
+						 "=l" ( discard_low ),
+						 "=l" ( discard_high ),
+						 "=l" ( discard_temp ),
+						 "+m" ( *result )
+					       : "l" ( multiplicand_element ),
+						 "l" ( multiplier_element )
+					       : "cc" );
+		}
+	}
+}
diff --git a/src/arch/arm/core/arm_io.c b/src/arch/arm/core/arm_io.c
new file mode 100644
index 00000000..804014c9
--- /dev/null
+++ b/src/arch/arm/core/arm_io.c
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/io.h>
+#include <ipxe/arm_io.h>
+
+/** @file
+ *
+ * iPXE I/O API for ARM
+ *
+ */
+
+/** An ARM I/O qword */
+union arm_io_qword {
+	uint64_t qword;
+	uint32_t dword[2];
+};
+
+/**
+ * Read 64-bit qword from memory-mapped device
+ *
+ * @v io_addr		I/O address
+ * @ret data		Value read
+ *
+ * This is not atomic for ARM.
+ */
+static uint64_t arm_readq ( volatile uint64_t *io_addr ) {
+	volatile union arm_io_qword *ptr =
+		container_of ( io_addr, union arm_io_qword, qword );
+	union arm_io_qword tmp;
+
+	tmp.dword[0] = readl ( &ptr->dword[0] );
+	tmp.dword[1] = readl ( &ptr->dword[1] );
+	return tmp.qword;
+}
+
+/**
+ * Write 64-bit qword to memory-mapped device
+ *
+ * @v data		Value to write
+ * @v io_addr		I/O address
+ *
+ * This is not atomic for ARM.
+ */
+static void arm_writeq ( uint64_t data, volatile uint64_t *io_addr ) {
+	volatile union arm_io_qword *ptr =
+		container_of ( io_addr, union arm_io_qword, qword );
+	union arm_io_qword tmp;
+
+	tmp.qword = data;
+	writel ( tmp.dword[0], &ptr->dword[0] );
+	writel ( tmp.dword[1], &ptr->dword[1] );
+}
+
+PROVIDE_IOAPI_INLINE ( arm, phys_to_bus );
+PROVIDE_IOAPI_INLINE ( arm, bus_to_phys );
+PROVIDE_IOAPI_INLINE ( arm, readb );
+PROVIDE_IOAPI_INLINE ( arm, readw );
+PROVIDE_IOAPI_INLINE ( arm, readl );
+PROVIDE_IOAPI_INLINE ( arm, writeb );
+PROVIDE_IOAPI_INLINE ( arm, writew );
+PROVIDE_IOAPI_INLINE ( arm, writel );
+PROVIDE_IOAPI_INLINE ( arm, iodelay );
+PROVIDE_IOAPI_INLINE ( arm, mb );
+PROVIDE_IOAPI ( arm, readq, arm_readq );
+PROVIDE_IOAPI ( arm, writeq, arm_writeq );
diff --git a/src/arch/arm/core/setjmp.S b/src/arch/arm/core/setjmp.S
new file mode 100644
index 00000000..7e7b0fe5
--- /dev/null
+++ b/src/arch/arm/core/setjmp.S
@@ -0,0 +1,32 @@
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
+
+	.text
+	.arm
+
+/*
+ * Save stack context for non-local goto
+ */
+	.globl	setjmp
+	.type	setjmp, %function
+setjmp:
+	/* Store registers */
+	stmia	r0, { r4, r5, r6, r7, r8, r9, r10, fp, sp, lr }
+	/* Return 0 when returning as setjmp() */
+	mov	r0, #0
+	bx	lr
+	.size	setjmp, . - setjmp
+
+/*
+ * Non-local jump to a saved stack context
+ */
+	.globl	longjmp
+	.type	longjmp, %function
+longjmp:
+	/* Restore registers */
+	ldmia	r0, { r4, r5, r6, r7, r8, r9, r10, fp, sp, lr }
+	/* Force result to non-zero */
+	movs	r0, r1
+	moveq	r0, #1
+	/* Return to setjmp() caller */
+	bx	lr
+	.size	longjmp, . - longjmp
diff --git a/src/arch/arm/include/bits/bigint.h b/src/arch/arm/include/bits/bigint.h
new file mode 100644
index 00000000..103c6c48
--- /dev/null
+++ b/src/arch/arm/include/bits/bigint.h
@@ -0,0 +1,316 @@
+#ifndef _BITS_BIGINT_H
+#define _BITS_BIGINT_H
+
+/** @file
+ *
+ * Big integer support
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+#include <string.h>
+#include <strings.h>
+
+/** Element of a big integer */
+typedef uint32_t bigint_element_t;
+
+/**
+ * Initialise big integer
+ *
+ * @v value0		Element 0 of big integer to initialise
+ * @v size		Number of elements
+ * @v data		Raw data
+ * @v len		Length of raw data
+ */
+static inline __attribute__ (( always_inline )) void
+bigint_init_raw ( uint32_t *value0, unsigned int size,
+		  const void *data, size_t len ) {
+	size_t pad_len = ( sizeof ( bigint_t ( size ) ) - len );
+	uint8_t *value_byte = ( ( void * ) value0 );
+	const uint8_t *data_byte = ( data + len );
+
+	/* Copy raw data in reverse order, padding with zeros */
+	while ( len-- )
+		*(value_byte++) = *(--data_byte);
+	while ( pad_len-- )
+		*(value_byte++) = 0;
+}
+
+/**
+ * Add big integers
+ *
+ * @v addend0		Element 0 of big integer to add
+ * @v value0		Element 0 of big integer to be added to
+ * @v size		Number of elements
+ */
+static inline __attribute__ (( always_inline )) void
+bigint_add_raw ( const uint32_t *addend0, uint32_t *value0,
+		 unsigned int size ) {
+	bigint_t ( size ) __attribute__ (( may_alias )) *value =
+		( ( void * ) value0 );
+	uint32_t *discard_addend;
+	uint32_t *discard_value;
+	uint32_t *discard_end;
+	uint32_t discard_addend_i;
+	uint32_t discard_value_i;
+
+	__asm__ __volatile__ ( "adds %2, %0, %8, lsl #2\n\t" /* clear CF */
+			       "\n1:\n\t"
+			       "ldmia %0!, {%3}\n\t"
+			       "ldr %4, [%1]\n\t"
+			       "adcs %4, %3\n\t"
+			       "stmia %1!, {%4}\n\t"
+			       "teq %0, %2\n\t"
+			       "bne 1b\n\t"
+			       : "=l" ( discard_addend ),
+				 "=l" ( discard_value ),
+				 "=l" ( discard_end ),
+				 "=l" ( discard_addend_i ),
+				 "=l" ( discard_value_i ),
+				 "+m" ( *value )
+			       : "0" ( addend0 ), "1" ( value0 ), "l" ( size )
+			       : "cc" );
+}
+
+/**
+ * Subtract big integers
+ *
+ * @v subtrahend0	Element 0 of big integer to subtract
+ * @v value0		Element 0 of big integer to be subtracted from
+ * @v size		Number of elements
+ */
+static inline __attribute__ (( always_inline )) void
+bigint_subtract_raw ( const uint32_t *subtrahend0, uint32_t *value0,
+		      unsigned int size ) {
+	bigint_t ( size ) __attribute__ (( may_alias )) *value =
+		( ( void * ) value0 );
+	uint32_t *discard_subtrahend;
+	uint32_t *discard_value;
+	uint32_t *discard_end;
+	uint32_t discard_subtrahend_i;
+	uint32_t discard_value_i;
+
+	__asm__ __volatile__ ( "add %2, %0, %8, lsl #2\n\t"
+			       "cmp %2, %0\n\t" /* set CF */
+			       "\n1:\n\t"
+			       "ldmia %0!, {%3}\n\t"
+			       "ldr %4, [%1]\n\t"
+			       "sbcs %4, %3\n\t"
+			       "stmia %1!, {%4}\n\t"
+			       "teq %0, %2\n\t"
+			       "bne 1b\n\t"
+			       : "=l" ( discard_subtrahend ),
+				 "=l" ( discard_value ),
+				 "=l" ( discard_end ),
+				 "=l" ( discard_subtrahend_i ),
+				 "=l" ( discard_value_i ),
+				 "+m" ( *value )
+			       : "0" ( subtrahend0 ), "1" ( value0 ),
+				 "l" ( size )
+			       : "cc" );
+}
+
+/**
+ * Rotate big integer left
+ *
+ * @v value0		Element 0 of big integer
+ * @v size		Number of elements
+ */
+static inline __attribute__ (( always_inline )) void
+bigint_rol_raw ( uint32_t *value0, unsigned int size ) {
+	bigint_t ( size ) __attribute__ (( may_alias )) *value =
+		( ( void * ) value0 );
+	uint32_t *discard_value;
+	uint32_t *discard_end;
+	uint32_t discard_value_i;
+
+	__asm__ __volatile__ ( "adds %1, %0, %5, lsl #2\n\t" /* clear CF */
+			       "\n1:\n\t"
+			       "ldr %2, [%0]\n\t"
+			       "adcs %2, %2\n\t"
+			       "stmia %0!, {%2}\n\t"
+			       "teq %0, %1\n\t"
+			       "bne 1b\n\t"
+			       : "=l" ( discard_value ),
+				 "=l" ( discard_end ),
+				 "=l" ( discard_value_i ),
+				 "+m" ( *value )
+			       : "0" ( value0 ), "1" ( size )
+			       : "cc" );
+}
+
+/**
+ * Rotate big integer right
+ *
+ * @v value0		Element 0 of big integer
+ * @v size		Number of elements
+ */
+static inline __attribute__ (( always_inline )) void
+bigint_ror_raw ( uint32_t *value0, unsigned int size ) {
+	bigint_t ( size ) __attribute__ (( may_alias )) *value =
+		( ( void * ) value0 );
+	uint32_t *discard_value;
+	uint32_t *discard_end;
+	uint32_t discard_value_i;
+
+	__asm__ __volatile__ ( "adds %1, %0, %5, lsl #2\n\t" /* clear CF */
+			       "\n1:\n\t"
+			       "ldmdb %1!, {%2}\n\t"
+			       "rrxs %2, %2\n\t"
+			       "str %2, [%1]\n\t"
+			       "teq %0, %1\n\t"
+			       "bne 1b\n\t"
+			       : "=l" ( discard_value ),
+				 "=l" ( discard_end ),
+				 "=l" ( discard_value_i ),
+				 "+m" ( *value )
+			       : "0" ( value0 ), "1" ( size )
+			       : "cc" );
+}
+
+/**
+ * Test if big integer is equal to zero
+ *
+ * @v value0		Element 0 of big integer
+ * @v size		Number of elements
+ * @ret is_zero		Big integer is equal to zero
+ */
+static inline __attribute__ (( always_inline, pure )) int
+bigint_is_zero_raw ( const uint32_t *value0, unsigned int size ) {
+	const uint32_t *value = value0;
+	uint32_t value_i;
+
+	do {
+		value_i = *(value++);
+		if ( value_i )
+			break;
+	} while ( --size );
+
+	return ( value_i == 0 );
+}
+
+/**
+ * Compare big integers
+ *
+ * @v value0		Element 0 of big integer
+ * @v reference0	Element 0 of reference big integer
+ * @v size		Number of elements
+ * @ret geq		Big integer is greater than or equal to the reference
+ */
+static inline __attribute__ (( always_inline, pure )) int
+bigint_is_geq_raw ( const uint32_t *value0, const uint32_t *reference0,
+		    unsigned int size ) {
+	const uint32_t *value = ( value0 + size );
+	const uint32_t *reference = ( reference0 + size );
+	uint32_t value_i;
+	uint32_t reference_i;
+
+	do {
+		value_i = *(--value);
+		reference_i = *(--reference);
+		if ( value_i != reference_i )
+			break;
+	} while ( --size );
+
+	return ( value_i >= reference_i );
+}
+
+/**
+ * Test if bit is set in big integer
+ *
+ * @v value0		Element 0 of big integer
+ * @v size		Number of elements
+ * @v bit		Bit to test
+ * @ret is_set		Bit is set
+ */
+static inline __attribute__ (( always_inline )) int
+bigint_bit_is_set_raw ( const uint32_t *value0, unsigned int size,
+			unsigned int bit ) {
+	const bigint_t ( size ) __attribute__ (( may_alias )) *value =
+		( ( const void * ) value0 );
+	unsigned int index = ( bit / ( 8 * sizeof ( value->element[0] ) ) );
+	unsigned int subindex = ( bit % ( 8 * sizeof ( value->element[0] ) ) );
+
+	return ( value->element[index] & ( 1 << subindex ) );
+}
+
+/**
+ * Find highest bit set in big integer
+ *
+ * @v value0		Element 0 of big integer
+ * @v size		Number of elements
+ * @ret max_bit		Highest bit set + 1 (or 0 if no bits set)
+ */
+static inline __attribute__ (( always_inline )) int
+bigint_max_set_bit_raw ( const uint32_t *value0, unsigned int size ) {
+	const uint32_t *value = ( value0 + size );
+	int max_bit = ( 8 * sizeof ( bigint_t ( size ) ) );
+	uint32_t value_i;
+
+	do {
+		value_i = *(--value);
+		max_bit -= ( 32 - fls ( value_i ) );
+		if ( value_i )
+			break;
+	} while ( --size );
+
+	return max_bit;
+}
+
+/**
+ * Grow big integer
+ *
+ * @v source0		Element 0 of source big integer
+ * @v source_size	Number of elements in source big integer
+ * @v dest0		Element 0 of destination big integer
+ * @v dest_size		Number of elements in destination big integer
+ */
+static inline __attribute__ (( always_inline )) void
+bigint_grow_raw ( const uint32_t *source0, unsigned int source_size,
+		  uint32_t *dest0, unsigned int dest_size ) {
+	unsigned int pad_size = ( dest_size - source_size );
+
+	memcpy ( dest0, source0, sizeof ( bigint_t ( source_size ) ) );
+	memset ( ( dest0 + source_size ), 0, sizeof ( bigint_t ( pad_size ) ) );
+}
+
+/**
+ * Shrink big integer
+ *
+ * @v source0		Element 0 of source big integer
+ * @v source_size	Number of elements in source big integer
+ * @v dest0		Element 0 of destination big integer
+ * @v dest_size		Number of elements in destination big integer
+ */
+static inline __attribute__ (( always_inline )) void
+bigint_shrink_raw ( const uint32_t *source0, unsigned int source_size __unused,
+		    uint32_t *dest0, unsigned int dest_size ) {
+
+	memcpy ( dest0, source0, sizeof ( bigint_t ( dest_size ) ) );
+}
+
+/**
+ * Finalise big integer
+ *
+ * @v value0		Element 0 of big integer to finalise
+ * @v size		Number of elements
+ * @v out		Output buffer
+ * @v len		Length of output buffer
+ */
+static inline __attribute__ (( always_inline )) void
+bigint_done_raw ( const uint32_t *value0, unsigned int size __unused,
+		  void *out, size_t len ) {
+	const uint8_t *value_byte = ( ( const void * ) value0 );
+	uint8_t *out_byte = ( out + len );
+
+	/* Copy raw data in reverse order */
+	while ( len-- )
+		*(--out_byte) = *(value_byte++);
+}
+
+extern void bigint_multiply_raw ( const uint32_t *multiplicand0,
+				  const uint32_t *multiplier0,
+				  uint32_t *value0, unsigned int size );
+
+#endif /* _BITS_BIGINT_H */
diff --git a/src/arch/arm/include/bits/bitops.h b/src/arch/arm/include/bits/bitops.h
new file mode 100644
index 00000000..9a5fe14c
--- /dev/null
+++ b/src/arch/arm/include/bits/bitops.h
@@ -0,0 +1,100 @@
+#ifndef _BITS_BITOPS_H
+#define _BITS_BITOPS_H
+
+/** @file
+ *
+ * ARM bit operations
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+
+/**
+ * Test and set bit atomically
+ *
+ * @v bit		Bit to set
+ * @v bits		Bit field
+ * @ret old		Old value of bit (zero or non-zero)
+ */
+static inline __attribute__ (( always_inline )) int
+test_and_set_bit ( unsigned int bit, volatile void *bits ) {
+	unsigned int index = ( bit / 32 );
+	unsigned int offset = ( bit % 32 );
+	volatile uint32_t *dword = ( ( ( volatile uint32_t * ) bits ) + index );
+	uint32_t mask = ( 1UL << offset );
+	uint32_t old;
+	uint32_t new;
+	uint32_t flag;
+
+	__asm__ __volatile__ ( "\n1:\n\t"
+			       "ldrex %0, %3\n\t"
+			       "orr %1, %0, %4\n\t"
+			       "strex %2, %1, %3\n\t"
+			       "tst %2, %2\n\t"
+			       "bne 1b\n\t"
+			       : "=&r" ( old ), "=&r" ( new ), "=&l" ( flag ),
+				 "+Q" ( *dword )
+			       : "r" ( mask )
+			       : "cc" );
+
+	return ( old & mask );
+}
+
+/**
+ * Test and clear bit atomically
+ *
+ * @v bit		Bit to set
+ * @v bits		Bit field
+ * @ret old		Old value of bit (zero or non-zero)
+ */
+static inline __attribute__ (( always_inline )) int
+test_and_clear_bit ( unsigned int bit, volatile void *bits ) {
+	unsigned int index = ( bit / 32 );
+	unsigned int offset = ( bit % 32 );
+	volatile uint32_t *dword = ( ( ( volatile uint32_t * ) bits ) + index );
+	uint32_t mask = ( 1UL << offset );
+	uint32_t old;
+	uint32_t new;
+	uint32_t flag;
+
+	__asm__ __volatile__ ( "\n1:\n\t"
+			       "ldrex %0, %3\n\t"
+			       "bic %1, %0, %4\n\t"
+			       "strex %2, %1, %3\n\t"
+			       "tst %2, %2\n\t"
+			       "bne 1b\n\t"
+			       : "=&r" ( old ), "=&r" ( new ), "=&l" ( flag ),
+				 "+Q" ( *dword )
+			       : "r" ( mask )
+			       : "cc" );
+
+	return ( old & mask );
+}
+
+/**
+ * Set bit atomically
+ *
+ * @v bit		Bit to set
+ * @v bits		Bit field
+ */
+static inline __attribute__ (( always_inline )) void
+set_bit ( unsigned int bit, volatile void *bits ) {
+
+	test_and_set_bit ( bit, bits );
+}
+
+/**
+ * Clear bit atomically
+ *
+ * @v bit		Bit to set
+ * @v bits		Bit field
+ */
+static inline __attribute__ (( always_inline )) void
+clear_bit ( unsigned int bit, volatile void *bits ) {
+
+	test_and_clear_bit ( bit, bits );
+}
+
+#endif /* _BITS_BITOPS_H */
diff --git a/src/arch/arm/include/bits/byteswap.h b/src/arch/arm/include/bits/byteswap.h
new file mode 100644
index 00000000..1fc884bd
--- /dev/null
+++ b/src/arch/arm/include/bits/byteswap.h
@@ -0,0 +1,52 @@
+#ifndef _BITS_BYTESWAP_H
+#define _BITS_BYTESWAP_H
+
+/** @file
+ *
+ * Byte-order swapping functions
+ *
+ */
+
+#include <stdint.h>
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+static inline __attribute__ (( always_inline, const )) uint16_t
+__bswap_variable_16 ( uint16_t x ) {
+	__asm__ ( "rev16 %0, %1" : "=l" ( x ) : "l" ( x ) );
+	return x;
+}
+
+static inline __attribute__ (( always_inline )) void
+__bswap_16s ( uint16_t *x ) {
+	*x = __bswap_variable_16 ( *x );
+}
+
+static inline __attribute__ (( always_inline, const )) uint32_t
+__bswap_variable_32 ( uint32_t x ) {
+	__asm__ ( "rev %0, %1" : "=l" ( x ) : "l" ( x ) );
+	return x;
+}
+
+static inline __attribute__ (( always_inline )) void
+__bswap_32s ( uint32_t *x ) {
+	*x = __bswap_variable_32 ( *x );
+}
+
+static inline __attribute__ (( always_inline, const )) uint64_t
+__bswap_variable_64 ( uint64_t x ) {
+	uint32_t in_high = ( x >> 32 );
+	uint32_t in_low = ( x & 0xffffffffUL );
+	uint32_t out_high = __bswap_variable_32 ( in_low );
+	uint32_t out_low = __bswap_variable_32 ( in_high );
+
+	return ( ( ( ( uint64_t ) out_high ) << 32 ) |
+		 ( ( uint64_t ) out_low ) );
+}
+
+static inline __attribute__ (( always_inline )) void
+__bswap_64s ( uint64_t *x ) {
+	*x = __bswap_variable_64 ( *x );
+}
+
+#endif
diff --git a/src/arch/arm/include/bits/compiler.h b/src/arch/arm/include/bits/compiler.h
new file mode 100644
index 00000000..e420cf92
--- /dev/null
+++ b/src/arch/arm/include/bits/compiler.h
@@ -0,0 +1,16 @@
+#ifndef _BITS_COMPILER_H
+#define _BITS_COMPILER_H
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** Dummy relocation type */
+#define RELOC_TYPE_NONE R_ARM_NONE
+
+#ifndef ASSEMBLY
+
+#define __asmcall
+#define __libgcc
+
+#endif /* ASSEMBLY */
+
+#endif /*_BITS_COMPILER_H */
diff --git a/src/arch/arm/include/bits/endian.h b/src/arch/arm/include/bits/endian.h
new file mode 100644
index 00000000..4506711a
--- /dev/null
+++ b/src/arch/arm/include/bits/endian.h
@@ -0,0 +1,13 @@
+#ifndef _BITS_ENDIAN_H
+#define _BITS_ENDIAN_H
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/* ARM may be either little-endian or big-endian */
+#ifdef __ARM_BIG_ENDIAN
+#define __BYTE_ORDER __BIG_ENDIAN
+#else
+#define __BYTE_ORDER __LITTLE_ENDIAN
+#endif
+
+#endif /* _BITS_ENDIAN_H */
diff --git a/src/arch/arm/include/bits/entropy.h b/src/arch/arm/include/bits/entropy.h
new file mode 100644
index 00000000..75fdc90e
--- /dev/null
+++ b/src/arch/arm/include/bits/entropy.h
@@ -0,0 +1,12 @@
+#ifndef _BITS_ENTROPY_H
+#define _BITS_ENTROPY_H
+
+/** @file
+ *
+ * ARM-specific entropy API implementations
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_ENTROPY_H */
diff --git a/src/arch/arm/include/bits/errfile.h b/src/arch/arm/include/bits/errfile.h
new file mode 100644
index 00000000..65f7f719
--- /dev/null
+++ b/src/arch/arm/include/bits/errfile.h
@@ -0,0 +1,19 @@
+#ifndef _BITS_ERRFILE_H
+#define _BITS_ERRFILE_H
+
+/** @file
+ *
+ * ARM-specific error file identifiers
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/**
+ * @addtogroup errfile Error file identifiers
+ * @{
+ */
+
+/** @} */
+
+#endif /* _BITS_ERRFILE_H */
diff --git a/src/arch/arm/include/bits/hyperv.h b/src/arch/arm/include/bits/hyperv.h
new file mode 100644
index 00000000..f0e0c879
--- /dev/null
+++ b/src/arch/arm/include/bits/hyperv.h
@@ -0,0 +1,12 @@
+#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/io.h b/src/arch/arm/include/bits/io.h
new file mode 100644
index 00000000..90f6455e
--- /dev/null
+++ b/src/arch/arm/include/bits/io.h
@@ -0,0 +1,14 @@
+#ifndef _BITS_IO_H
+#define _BITS_IO_H
+
+/** @file
+ *
+ * ARM-specific I/O API implementations
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/arm_io.h>
+
+#endif /* _BITS_IO_H */
diff --git a/src/arch/arm/include/bits/iomap.h b/src/arch/arm/include/bits/iomap.h
new file mode 100644
index 00000000..ae953c45
--- /dev/null
+++ b/src/arch/arm/include/bits/iomap.h
@@ -0,0 +1,12 @@
+#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/nap.h b/src/arch/arm/include/bits/nap.h
new file mode 100644
index 00000000..e30a7146
--- /dev/null
+++ b/src/arch/arm/include/bits/nap.h
@@ -0,0 +1,14 @@
+#ifndef _BITS_NAP_H
+#define _BITS_NAP_H
+
+/** @file
+ *
+ * ARM-specific CPU sleeping API implementations
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/efi/efiarm_nap.h>
+
+#endif /* _BITS_MAP_H */
diff --git a/src/arch/arm/include/bits/pci_io.h b/src/arch/arm/include/bits/pci_io.h
new file mode 100644
index 00000000..fba0eb97
--- /dev/null
+++ b/src/arch/arm/include/bits/pci_io.h
@@ -0,0 +1,14 @@
+#ifndef _BITS_PCI_IO_H
+#define _BITS_PCI_IO_H
+
+/** @file
+ *
+ * ARM PCI I/O API implementations
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/io.h>
+
+#endif /* _BITS_PCI_IO_H */
diff --git a/src/arch/arm/include/bits/profile.h b/src/arch/arm/include/bits/profile.h
new file mode 100644
index 00000000..2b15d160
--- /dev/null
+++ b/src/arch/arm/include/bits/profile.h
@@ -0,0 +1,30 @@
+#ifndef _BITS_PROFILE_H
+#define _BITS_PROFILE_H
+
+/** @file
+ *
+ * Profiling
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+
+/**
+ * Get profiling timestamp
+ *
+ * @ret timestamp	Timestamp
+ */
+static inline __attribute__ (( always_inline )) uint64_t
+profile_timestamp ( void ) {
+	uint32_t cycles;
+
+	/* Read cycle counter */
+	__asm__ __volatile__ ( "mcr p15, 0, %1, c9, c12, 0\n\t"
+			       "mrc p15, 0, %0, c9, c13, 0\n\t"
+			       : "=r" ( cycles ) : "r" ( 1 ) );
+	return cycles;
+}
+
+#endif /* _BITS_PROFILE_H */
diff --git a/src/arch/arm/include/bits/reboot.h b/src/arch/arm/include/bits/reboot.h
new file mode 100644
index 00000000..88c50250
--- /dev/null
+++ b/src/arch/arm/include/bits/reboot.h
@@ -0,0 +1,12 @@
+#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
new file mode 100644
index 00000000..abd4c79a
--- /dev/null
+++ b/src/arch/arm/include/bits/sanboot.h
@@ -0,0 +1,12 @@
+#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
new file mode 100644
index 00000000..d9421811
--- /dev/null
+++ b/src/arch/arm/include/bits/smbios.h
@@ -0,0 +1,12 @@
+#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/stdint.h b/src/arch/arm/include/bits/stdint.h
new file mode 100644
index 00000000..fe1f9946
--- /dev/null
+++ b/src/arch/arm/include/bits/stdint.h
@@ -0,0 +1,23 @@
+#ifndef _BITS_STDINT_H
+#define _BITS_STDINT_H
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+typedef __SIZE_TYPE__		size_t;
+typedef signed long		ssize_t;
+typedef signed long		off_t;
+
+typedef unsigned char		uint8_t;
+typedef unsigned short		uint16_t;
+typedef unsigned int		uint32_t;
+typedef unsigned long long	uint64_t;
+
+typedef signed char		int8_t;
+typedef signed short		int16_t;
+typedef signed int		int32_t;
+typedef signed long long	int64_t;
+
+typedef unsigned long		physaddr_t;
+typedef unsigned long		intptr_t;
+
+#endif /* _BITS_STDINT_H */
diff --git a/src/arch/arm/include/bits/string.h b/src/arch/arm/include/bits/string.h
new file mode 100644
index 00000000..5b1c1505
--- /dev/null
+++ b/src/arch/arm/include/bits/string.h
@@ -0,0 +1,60 @@
+#ifndef BITS_STRING_H
+#define BITS_STRING_H
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * String functions
+ *
+ */
+
+/**
+ * Fill memory region
+ *
+ * @v dest		Destination region
+ * @v character		Fill character
+ * @v len		Length
+ * @ret dest		Destination region
+ */
+static inline __attribute__ (( always_inline )) void *
+memset ( void *dest, int character, size_t len ) {
+
+	/* Not yet optimised */
+	generic_memset ( dest, character, len );
+	return dest;
+}
+
+/**
+ * Copy memory region
+ *
+ * @v dest		Destination region
+ * @v src		Source region
+ * @v len		Length
+ * @ret dest		Destination region
+ */
+static inline __attribute__ (( always_inline )) void *
+memcpy ( void *dest, const void *src, size_t len ) {
+
+	/* Not yet optimised */
+	generic_memcpy ( dest, src, len );
+	return dest;
+}
+
+/**
+ * Copy (possibly overlapping) memory region
+ *
+ * @v dest		Destination region
+ * @v src		Source region
+ * @v len		Length
+ * @ret dest		Destination region
+ */
+static inline __attribute__ (( always_inline )) void *
+memmove ( void *dest, const void *src, size_t len ) {
+
+	/* Not yet optimised */
+	generic_memmove ( dest, src, len );
+	return dest;
+}
+
+#endif /* BITS_STRING_H */
diff --git a/src/arch/arm/include/bits/strings.h b/src/arch/arm/include/bits/strings.h
new file mode 100644
index 00000000..adbd5f4b
--- /dev/null
+++ b/src/arch/arm/include/bits/strings.h
@@ -0,0 +1,85 @@
+#ifndef _BITS_STRINGS_H
+#define _BITS_STRINGS_H
+
+/** @file
+ *
+ * String functions
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/**
+ * Find first (i.e. least significant) set bit
+ *
+ * @v value		Value
+ * @ret lsb		Least significant bit set in value (LSB=1), or zero
+ */
+static inline __attribute__ (( always_inline )) int __ffsl ( long value ) {
+	unsigned long bits = value;
+	unsigned long lsb;
+	unsigned int lz;
+
+	/* Extract least significant set bit */
+	lsb = ( bits & -bits );
+
+	/* Count number of leading zeroes before LSB */
+	__asm__ ( "clz %0, %1" : "=r" ( lz ) : "r" ( lsb ) );
+
+	return ( 32 - lz );
+}
+
+/**
+ * Find first (i.e. least significant) set bit
+ *
+ * @v value		Value
+ * @ret lsb		Least significant bit set in value (LSB=1), or zero
+ */
+static inline __attribute__ (( always_inline )) int __ffsll ( long long value ){
+	unsigned long high = ( value >> 32 );
+	unsigned long low = ( value >> 0 );
+
+	if ( low ) {
+		return ( __ffsl ( low ) );
+	} else if ( high ) {
+		return ( 32 + __ffsl ( high ) );
+	} else {
+		return 0;
+	}
+}
+
+/**
+ * Find last (i.e. most significant) set bit
+ *
+ * @v value		Value
+ * @ret msb		Most significant bit set in value (LSB=1), or zero
+ */
+static inline __attribute__ (( always_inline )) int __flsl ( long value ) {
+	unsigned int lz;
+
+	/* Count number of leading zeroes */
+	__asm__ ( "clz %0, %1" : "=r" ( lz ) : "r" ( value ) );
+
+	return ( 32 - lz );
+}
+
+/**
+ * Find last (i.e. most significant) set bit
+ *
+ * @v value		Value
+ * @ret msb		Most significant bit set in value (LSB=1), or zero
+ */
+static inline __attribute__ (( always_inline )) int __flsll ( long long value ){
+	unsigned long high = ( value >> 32 );
+	unsigned long low = ( value >> 0 );
+
+	if ( high ) {
+		return ( 32 + __flsl ( high ) );
+	} else if ( low ) {
+		return ( __flsl ( low ) );
+	} else {
+		return 0;
+	}
+}
+
+#endif /* _BITS_STRINGS_H */
diff --git a/src/arch/arm/include/bits/tcpip.h b/src/arch/arm/include/bits/tcpip.h
new file mode 100644
index 00000000..fc3c5b3f
--- /dev/null
+++ b/src/arch/arm/include/bits/tcpip.h
@@ -0,0 +1,19 @@
+#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/arm/include/bits/time.h b/src/arch/arm/include/bits/time.h
new file mode 100644
index 00000000..724d8b93
--- /dev/null
+++ b/src/arch/arm/include/bits/time.h
@@ -0,0 +1,12 @@
+#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/timer.h b/src/arch/arm/include/bits/timer.h
new file mode 100644
index 00000000..64e7d31d
--- /dev/null
+++ b/src/arch/arm/include/bits/timer.h
@@ -0,0 +1,12 @@
+#ifndef _BITS_TIMER_H
+#define _BITS_TIMER_H
+
+/** @file
+ *
+ * ARM-specific timer API implementations
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#endif /* _BITS_TIMER_H */
diff --git a/src/arch/arm/include/bits/uaccess.h b/src/arch/arm/include/bits/uaccess.h
new file mode 100644
index 00000000..87f11509
--- /dev/null
+++ b/src/arch/arm/include/bits/uaccess.h
@@ -0,0 +1,12 @@
+#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
new file mode 100644
index 00000000..6f85975f
--- /dev/null
+++ b/src/arch/arm/include/bits/uart.h
@@ -0,0 +1,12 @@
+#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
new file mode 100644
index 00000000..27970d7b
--- /dev/null
+++ b/src/arch/arm/include/bits/umalloc.h
@@ -0,0 +1,12 @@
+#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/arm/include/bits/xen.h b/src/arch/arm/include/bits/xen.h
new file mode 100644
index 00000000..c3808a73
--- /dev/null
+++ b/src/arch/arm/include/bits/xen.h
@@ -0,0 +1,149 @@
+#ifndef _BITS_XEN_H
+#define _BITS_XEN_H
+
+/** @file
+ *
+ * Xen interface
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/* Hypercall registers */
+#define XEN_HC "r12"
+#define XEN_REG1 "r0"
+#define XEN_REG2 "r1"
+#define XEN_REG3 "r2"
+#define XEN_REG4 "r3"
+#define XEN_REG5 "r4"
+
+/**
+ * Issue hypercall with one argument
+ *
+ * @v xen		Xen hypervisor
+ * @v hypercall		Hypercall number
+ * @v arg1		First argument
+ * @ret retval		Return value
+ */
+static inline __attribute__ (( always_inline )) unsigned long
+xen_hypercall_1 ( struct xen_hypervisor *xen __unused, unsigned int hypercall,
+		  unsigned long arg1 ) {
+	register unsigned long hc asm ( XEN_HC ) = hypercall;
+	register unsigned long reg1 asm ( XEN_REG1 ) = arg1;
+
+	__asm__ __volatile__ ( "hvc %1"
+			       : "+r" ( reg1 )
+			       : "i" ( XEN_HYPERCALL_TAG ), "r" ( hc )
+			       : "memory", "cc" );
+	return reg1;
+}
+
+/**
+ * Issue hypercall with two arguments
+ *
+ * @v xen		Xen hypervisor
+ * @v hypercall		Hypercall number
+ * @v arg1		First argument
+ * @v arg2		Second argument
+ * @ret retval		Return value
+ */
+static inline __attribute__ (( always_inline )) unsigned long
+xen_hypercall_2 ( struct xen_hypervisor *xen __unused, unsigned int hypercall,
+		  unsigned long arg1, unsigned long arg2 ) {
+	register unsigned long hc asm ( XEN_HC ) = hypercall;
+	register unsigned long reg1 asm ( XEN_REG1 ) = arg1;
+	register unsigned long reg2 asm ( XEN_REG2 ) = arg2;
+
+	__asm__ __volatile__ ( "hvc %2"
+			       : "+r" ( reg1 ), "+r" ( reg2 )
+			       : "i" ( XEN_HYPERCALL_TAG ), "r" ( hc )
+			       : "memory", "cc" );
+	return reg1;
+}
+
+/**
+ * Issue hypercall with three arguments
+ *
+ * @v xen		Xen hypervisor
+ * @v hypercall		Hypercall number
+ * @v arg1		First argument
+ * @v arg2		Second argument
+ * @v arg3		Third argument
+ * @ret retval		Return value
+ */
+static inline __attribute__ (( always_inline )) unsigned long
+xen_hypercall_3 ( struct xen_hypervisor *xen __unused, unsigned int hypercall,
+		  unsigned long arg1, unsigned long arg2, unsigned long arg3 ) {
+	register unsigned long hc asm ( XEN_HC ) = hypercall;
+	register unsigned long reg1 asm ( XEN_REG1 ) = arg1;
+	register unsigned long reg2 asm ( XEN_REG2 ) = arg2;
+	register unsigned long reg3 asm ( XEN_REG3 ) = arg3;
+
+	__asm__ __volatile__ ( "hvc %3"
+			       : "+r" ( reg1 ), "+r" ( reg2 ), "+r" ( reg3 )
+			       : "i" ( XEN_HYPERCALL_TAG ), "r" ( hc )
+			       : "memory", "cc" );
+	return reg1;
+}
+
+/**
+ * Issue hypercall with four arguments
+ *
+ * @v xen		Xen hypervisor
+ * @v hypercall		Hypercall number
+ * @v arg1		First argument
+ * @v arg2		Second argument
+ * @v arg3		Third argument
+ * @v arg4		Fourth argument
+ * @ret retval		Return value
+ */
+static inline __attribute__ (( always_inline )) unsigned long
+xen_hypercall_4 ( struct xen_hypervisor *xen __unused, unsigned int hypercall,
+		  unsigned long arg1, unsigned long arg2, unsigned long arg3,
+		  unsigned long arg4 ) {
+	register unsigned long hc asm ( XEN_HC ) = hypercall;
+	register unsigned long reg1 asm ( XEN_REG1 ) = arg1;
+	register unsigned long reg2 asm ( XEN_REG2 ) = arg2;
+	register unsigned long reg3 asm ( XEN_REG3 ) = arg3;
+	register unsigned long reg4 asm ( XEN_REG4 ) = arg4;
+
+	__asm__ __volatile__ ( "hvc %4"
+			       : "+r" ( reg1 ), "+r" ( reg2 ), "+r" ( reg3 ),
+				 "+r" ( reg4 )
+			       : "i" ( XEN_HYPERCALL_TAG ), "r" ( hc )
+			       : "memory", "cc" );
+	return reg1;
+}
+
+/**
+ * Issue hypercall with five arguments
+ *
+ * @v xen		Xen hypervisor
+ * @v hypercall		Hypercall number
+ * @v arg1		First argument
+ * @v arg2		Second argument
+ * @v arg3		Third argument
+ * @v arg4		Fourth argument
+ * @v arg5		Fifth argument
+ * @ret retval		Return value
+ */
+static inline __attribute__ (( always_inline )) unsigned long
+xen_hypercall_5 ( struct xen_hypervisor *xen __unused, unsigned int hypercall,
+		  unsigned long arg1, unsigned long arg2, unsigned long arg3,
+		  unsigned long arg4, unsigned long arg5 ) {
+	register unsigned long hc asm ( XEN_HC ) = hypercall;
+	register unsigned long reg1 asm ( XEN_REG1 ) = arg1;
+	register unsigned long reg2 asm ( XEN_REG2 ) = arg2;
+	register unsigned long reg3 asm ( XEN_REG3 ) = arg3;
+	register unsigned long reg4 asm ( XEN_REG4 ) = arg4;
+	register unsigned long reg5 asm ( XEN_REG5 ) = arg5;
+
+	__asm__ __volatile__ ( "hvc %5"
+			       : "+r" ( reg1 ), "+r" ( reg2 ), "+r" ( reg3 ),
+				 "+r" ( reg4 ), "+r" ( reg5 )
+			       : "i" ( XEN_HYPERCALL_TAG ), "r" ( hc )
+			       : "memory", "cc" );
+	return reg1;
+}
+
+#endif /* _BITS_XEN_H */
diff --git a/src/arch/arm/include/efi/ipxe/dhcp_arch.h b/src/arch/arm/include/efi/ipxe/dhcp_arch.h
new file mode 100644
index 00000000..f403d4ce
--- /dev/null
+++ b/src/arch/arm/include/efi/ipxe/dhcp_arch.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+#ifndef _DHCP_ARCH_H
+#define _DHCP_ARCH_H
+
+/** @file
+ *
+ * Architecture-specific DHCP options
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/dhcp.h>
+
+#define DHCP_ARCH_VENDOR_CLASS_ID \
+	DHCP_STRING ( 'P', 'X', 'E', 'C', 'l', 'i', 'e', 'n', 't', ':',      \
+		      'A', 'r', 'c', 'h', ':', '0', '0', '0', '0', '7', ':', \
+		      'U', 'N', 'D', 'I', ':', '0', '0', '3', '0', '1', '0' )
+
+#define DHCP_ARCH_CLIENT_ARCHITECTURE \
+	DHCP_WORD ( DHCP_CLIENT_ARCHITECTURE_EFI )
+
+#define DHCP_ARCH_CLIENT_NDI DHCP_OPTION ( 1 /* UNDI */ , 3, 10 /* v3.10 */ )
+
+#endif
diff --git a/src/arch/arm/include/gdbmach.h b/src/arch/arm/include/gdbmach.h
new file mode 100644
index 00000000..cd152eed
--- /dev/null
+++ b/src/arch/arm/include/gdbmach.h
@@ -0,0 +1,45 @@
+#ifndef GDBMACH_H
+#define GDBMACH_H
+
+/** @file
+ *
+ * GDB architecture specifics
+ *
+ * This file declares functions for manipulating the machine state and
+ * debugging context.
+ *
+ */
+
+#include <stdint.h>
+
+typedef unsigned long gdbreg_t;
+
+/* Register snapshot */
+enum {
+	/* Not yet implemented */
+	GDBMACH_NREGS,
+};
+
+#define GDBMACH_SIZEOF_REGS ( GDBMACH_NREGS * sizeof ( gdbreg_t ) )
+
+static inline void gdbmach_set_pc ( gdbreg_t *regs, gdbreg_t pc ) {
+	/* Not yet implemented */
+	( void ) regs;
+	( void ) pc;
+}
+
+static inline void gdbmach_set_single_step ( gdbreg_t *regs, int step ) {
+	/* Not yet implemented */
+	( void ) regs;
+	( void ) step;
+}
+
+static inline void gdbmach_breakpoint ( void ) {
+	/* Not yet implemented */
+}
+
+extern int gdbmach_set_breakpoint ( int type, unsigned long addr, size_t len,
+				    int enable );
+extern void gdbmach_init ( void );
+
+#endif /* GDBMACH_H */
diff --git a/src/arch/arm/include/ipxe/arm_io.h b/src/arch/arm/include/ipxe/arm_io.h
new file mode 100644
index 00000000..e13de15f
--- /dev/null
+++ b/src/arch/arm/include/ipxe/arm_io.h
@@ -0,0 +1,89 @@
+#ifndef _IPXE_ARM_IO_H
+#define _IPXE_ARM_IO_H
+
+/** @file
+ *
+ * iPXE I/O API for ARM
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#ifdef IOAPI_ARM
+#define IOAPI_PREFIX_arm
+#else
+#define IOAPI_PREFIX_arm __arm_
+#endif
+
+/*
+ * Memory space mappings
+ *
+ */
+
+/** Page shift */
+#define PAGE_SHIFT 12
+
+/*
+ * Physical<->Bus address mappings
+ *
+ */
+
+static inline __always_inline unsigned long
+IOAPI_INLINE ( arm, phys_to_bus ) ( unsigned long phys_addr ) {
+	return phys_addr;
+}
+
+static inline __always_inline unsigned long
+IOAPI_INLINE ( arm, bus_to_phys ) ( unsigned long bus_addr ) {
+	return bus_addr;
+}
+
+/*
+ * MMIO reads and writes up to native word size
+ *
+ */
+
+#define ARM_READX( _api_func, _type, _insn_suffix )			      \
+static inline __always_inline _type					      \
+IOAPI_INLINE ( arm, _api_func ) ( volatile _type *io_addr ) {		      \
+	_type data;							      \
+	__asm__ __volatile__ ( "ldr" _insn_suffix " %0, %1"		      \
+			       : "=r" ( data ) : "Qo" ( *io_addr ) );	      \
+	return data;							      \
+}
+ARM_READX ( readb, uint8_t, "b" );
+ARM_READX ( readw, uint16_t, "h" );
+ARM_READX ( readl, uint32_t, "" );
+
+#define ARM_WRITEX( _api_func, _type, _insn_suffix )			      \
+static inline __always_inline void					      \
+IOAPI_INLINE ( arm, _api_func ) ( _type data,				      \
+				  volatile _type *io_addr ) {		      \
+	__asm__ __volatile__ ( "str" _insn_suffix " %0, %1"		      \
+			       : : "r" ( data ), "Qo" ( *io_addr ) );	      \
+}
+ARM_WRITEX ( writeb, uint8_t, "b" );
+ARM_WRITEX ( writew, uint16_t, "h" );
+ARM_WRITEX ( writel, uint32_t, "" );
+
+/*
+ * Slow down I/O
+ *
+ */
+
+static inline __always_inline void
+IOAPI_INLINE ( arm, iodelay ) ( void ) {
+	/* Nothing to do */
+}
+
+/*
+ * Memory barrier
+ *
+ */
+
+static inline __always_inline void
+IOAPI_INLINE ( arm, mb ) ( void ) {
+	__asm__ __volatile__ ( "dmb" );
+}
+
+#endif /* _IPXE_ARM_IO_H */
diff --git a/src/arch/arm/include/ipxe/efi/efiarm_nap.h b/src/arch/arm/include/ipxe/efi/efiarm_nap.h
new file mode 100644
index 00000000..dcbdd3e2
--- /dev/null
+++ b/src/arch/arm/include/ipxe/efi/efiarm_nap.h
@@ -0,0 +1,18 @@
+#ifndef _IPXE_EFIARM_NAP_H
+#define _IPXE_EFIARM_NAP_H
+
+/** @file
+ *
+ * EFI CPU sleeping
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#ifdef NAP_EFIARM
+#define NAP_PREFIX_efiarm
+#else
+#define NAP_PREFIX_efiarm __efiarm_
+#endif
+
+#endif /* _IPXE_EFIARM_NAP_H */
diff --git a/src/arch/arm/include/limits.h b/src/arch/arm/include/limits.h
new file mode 100644
index 00000000..bb48b75a
--- /dev/null
+++ b/src/arch/arm/include/limits.h
@@ -0,0 +1,61 @@
+#ifndef LIMITS_H
+#define LIMITS_H	1
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/* Number of bits in a `char' */
+#define CHAR_BIT	8
+
+/* Minimum and maximum values a `signed char' can hold */
+#define SCHAR_MIN	(-128)
+#define SCHAR_MAX	127
+
+/* Maximum value an `unsigned char' can hold. (Minimum is 0.) */
+#define UCHAR_MAX	255
+
+/* Minimum and maximum values a `char' can hold */
+#define CHAR_MIN	SCHAR_MIN
+#define CHAR_MAX	SCHAR_MAX
+
+/* Minimum and maximum values a `signed short int' can hold */
+#define SHRT_MIN	(-32768)
+#define SHRT_MAX	32767
+
+/* Maximum value an `unsigned short' can hold. (Minimum is 0.) */
+#define USHRT_MAX	65535
+
+
+/* Minimum and maximum values a `signed int' can hold */
+#define INT_MIN		(-INT_MAX - 1)
+#define INT_MAX		2147483647
+
+/* Maximum value an `unsigned int' can hold. (Minimum is 0.) */
+#define UINT_MAX	4294967295U
+
+
+/* Minimum and maximum values a `signed int' can hold */
+#define INT_MAX		2147483647
+#define INT_MIN		(-INT_MAX - 1)
+
+
+/* Maximum value an `unsigned int' can hold. (Minimum is 0.) */
+#define UINT_MAX	4294967295U
+
+
+/* Minimum and maximum values a `signed long' can hold */
+#define LONG_MAX	2147483647
+#define LONG_MIN	(-LONG_MAX - 1L)
+
+/* Maximum value an `unsigned long' can hold. (Minimum is 0.) */
+#define ULONG_MAX	4294967295UL
+
+/* Minimum and maximum values a `signed long long' can hold */
+#define LLONG_MAX	9223372036854775807LL
+#define LLONG_MIN	(-LONG_MAX - 1LL)
+
+
+/* Maximum value an `unsigned long long' can hold. (Minimum is 0.) */
+#define ULLONG_MAX	18446744073709551615ULL
+
+
+#endif /* LIMITS_H */
diff --git a/src/arch/arm/include/setjmp.h b/src/arch/arm/include/setjmp.h
new file mode 100644
index 00000000..4828b47a
--- /dev/null
+++ b/src/arch/arm/include/setjmp.h
@@ -0,0 +1,38 @@
+#ifndef _SETJMP_H
+#define _SETJMP_H
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+
+/** A jump buffer */
+typedef struct {
+	/** Saved r4 */
+	uint32_t r4;
+	/** Saved r5 */
+	uint32_t r5;
+	/** Saved r6 */
+	uint32_t r6;
+	/** Saved r7 */
+	uint32_t r7;
+	/** Saved r8 */
+	uint32_t r8;
+	/** Saved r9 */
+	uint32_t r9;
+	/** Saved r10 */
+	uint32_t r10;
+	/** Saved frame pointer (r11) */
+	uint32_t fp;
+	/** Saved stack pointer (r13) */
+	uint32_t sp;
+	/** Saved link register (r14) */
+	uint32_t lr;
+} jmp_buf[1];
+
+extern int __asmcall __attribute__ (( returns_twice ))
+setjmp ( jmp_buf env );
+
+extern void __asmcall __attribute__ (( noreturn ))
+longjmp ( jmp_buf env, int val );
+
+#endif /* _SETJMP_H */
diff --git a/src/arch/arm/interface/efi/efiarm_nap.c b/src/arch/arm/interface/efi/efiarm_nap.c
new file mode 100644
index 00000000..9ed638e9
--- /dev/null
+++ b/src/arch/arm/interface/efi/efiarm_nap.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/nap.h>
+#include <ipxe/efi/efi.h>
+
+/** @file
+ *
+ * iPXE CPU sleeping API for EFI
+ *
+ */
+
+/**
+ * Sleep until next interrupt
+ *
+ */
+static void efiarm_cpu_nap ( void ) {
+	/*
+	 * I can't find any EFI API that allows us to put the CPU to
+	 * sleep.  The CpuSleep() function is defined in CpuLib.h, but
+	 * isn't part of any exposed protocol so we have no way to
+	 * call it.
+	 *
+	 * The EFI shell doesn't seem to bother sleeping the CPU; it
+	 * just sits there idly burning power.
+	 *
+	 */
+	__asm__ __volatile__ ( "wfi" );
+}
+
+PROVIDE_NAP ( efiarm, cpu_nap, efiarm_cpu_nap );
diff --git a/src/arch/arm/libgcc/lldivmod.S b/src/arch/arm/libgcc/lldivmod.S
new file mode 100644
index 00000000..910be4b7
--- /dev/null
+++ b/src/arch/arm/libgcc/lldivmod.S
@@ -0,0 +1,50 @@
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
+
+	.text
+	.thumb
+
+/**
+ * Unsigned long long division
+ *
+ * @v r1:r0		Dividend
+ * @v r3:r2		Divisor
+ * @ret r1:r0		Quotient
+ * @ret r3:r2		Remainder
+ */
+	.section ".text.__aeabi_uldivmod", "ax", %progbits
+	.globl	__aeabi_uldivmod
+	.type	__aeabi_uldivmod, %function
+__aeabi_uldivmod:
+	/* Allocate stack space for remainder and pointer to remainder */
+	push	{r0, r1, r2, r3, r4, lr}
+	/* Call __udivmoddi4() */
+	add	r4, sp, #8
+	str	r4, [sp]
+	bl	__udivmoddi4
+	/* Retrieve remainder and return */
+	add	sp, sp, #8
+	pop	{r2, r3, r4, pc}
+	.size	__aeabi_uldivmod, . - __aeabi_uldivmod
+
+/**
+ * Signed long long division
+ *
+ * @v r1:r0		Dividend
+ * @v r3:r2		Divisor
+ * @ret r1:r0		Quotient
+ * @ret r3:r2		Remainder
+ */
+	.section ".text.__aeabi_ldivmod", "ax", %progbits
+	.globl	__aeabi_ldivmod
+	.type	__aeabi_ldivmod, %function
+__aeabi_ldivmod:
+	/* Allocate stack space for remainder and pointer to remainder */
+	push	{r0, r1, r2, r3, r4, lr}
+	/* Call __divmoddi4() */
+	add	r4, sp, #8
+	str	r4, [sp]
+	bl	__divmoddi4
+	/* Retrieve remainder and return */
+	add	sp, sp, #8
+	pop	{r2, r3, r4, pc}
+	.size	__aeabi_ldivmod, . - __aeabi_ldivmod
diff --git a/src/arch/arm/libgcc/llshift.S b/src/arch/arm/libgcc/llshift.S
new file mode 100644
index 00000000..cc16e261
--- /dev/null
+++ b/src/arch/arm/libgcc/llshift.S
@@ -0,0 +1,88 @@
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
+
+	.text
+	.arm
+
+/**
+ * Logical shift left
+ *
+ * @v r1:r0		Value to shift
+ * @v r2		Shift amount
+ * @ret r1:r0		Shifted value
+ */
+	.section ".text.__aeabi_llsl", "ax", %progbits
+	.globl	__aeabi_llsl
+	.type	__aeabi_llsl, %function
+__aeabi_llsl:
+	/* r3 = ( shift - 32 ) */
+	subs	r3, r2, #32
+	/* If shift >= 32, then
+	 *   high = ( low << ( shift - 32 ) )
+	 */
+	movpl	r1, r0, lsl r3
+	/* If shift < 32, then
+	 *   high = ( ( high << shift ) | ( low >> ( 32 - shift ) ) )
+	 */
+	movmi	r1, r1, lsl r2
+	rsbmi	r3, r2, #32
+	orrmi	r1, r1, r0, lsr r3
+	/* low = ( low << shift ) */
+	mov	r0, r0, lsl r2
+	bx	lr
+	.size	__aeabi_llsl, . - __aeabi_llsl
+
+/**
+ * Logical shift right
+ *
+ * @v r1:r0		Value to shift
+ * @v r2		Shift amount
+ * @ret r1:r0		Shifted value
+ */
+	.section ".text.__aeabi_llsr", "ax", %progbits
+	.globl	__aeabi_llsr
+	.type	__aeabi_llsr, %function
+__aeabi_llsr:
+	/* r3 = ( shift - 32 ) */
+	subs	r3, r2, #32
+	/* If shift >= 32, then
+	 *   low = ( high >> ( shift - 32 ) )
+	 */
+	movpl	r0, r1, lsr r3
+	/* If shift < 32, then
+	 *   low = ( ( low >> shift ) | ( high << ( 32 - shift ) ) )
+	 */
+	movmi	r0, r0, lsr r2
+	rsbmi	r3, r2, #32
+	orrmi	r0, r0, r1, lsl r3
+	/* high = ( high >> shift ) */
+	mov	r1, r1, lsr r2
+	bx	lr
+	.size	__aeabi_llsr, . - __aeabi_llsr
+
+/**
+ * Arithmetic shift right
+ *
+ * @v r1:r0		Value to shift
+ * @v r2		Shift amount
+ * @ret r1:r0		Shifted value
+ */
+	.section ".text.__aeabi_lasr", "ax", %progbits
+	.globl	__aeabi_lasr
+	.type	__aeabi_lasr, %function
+__aeabi_lasr:
+	/* r3 = ( shift - 32 ) */
+	subs	r3, r2, #32
+	/* If shift >= 32, then
+	 *   low = ( high >> ( shift - 32 ) )
+	 */
+	movpl	r0, r1, asr r3
+	/* If shift < 32, then
+	 *   low = ( ( low >> shift ) | ( high << ( 32 - shift ) ) )
+	 */
+	movmi	r0, r0, lsr r2
+	rsbmi	r3, r2, #32
+	orrmi	r0, r0, r1, lsl r3
+	/* high = ( high >> shift ) */
+	mov	r1, r1, asr r2
+	bx	lr
+	.size	__aeabi_lasr, . - __aeabi_lasr
diff --git a/src/config/defaults/efi.h b/src/config/defaults/efi.h
index ea9c31e2..8d3a8bf2 100644
--- a/src/config/defaults/efi.h
+++ b/src/config/defaults/efi.h
@@ -10,12 +10,10 @@
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 #define UACCESS_EFI
-#define IOAPI_X86
 #define IOMAP_VIRT
 #define PCIAPI_EFI
 #define CONSOLE_EFI
 #define TIMER_EFI
-#define NAP_EFIX86
 #define UMALLOC_EFI
 #define SMBIOS_EFI
 #define SANBOOT_NULL
@@ -35,6 +33,16 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define	USB_EFI			/* Provide EFI_USB_IO_PROTOCOL interface */
 
 #define	REBOOT_CMD		/* Reboot command */
+
+#if defined ( __i386__ ) || defined ( __x86_64__ )
+#define IOAPI_X86
+#define NAP_EFIX86
 #define	CPUID_CMD		/* x86 CPU feature detection command */
+#endif
+
+#if defined ( __arm__ )
+#define IOAPI_ARM
+#define NAP_EFIARM
+#endif
 
 #endif /* CONFIG_DEFAULTS_EFI_H */
diff --git a/src/util/efirom.c b/src/util/efirom.c
index a982c19a..72829cbd 100644
--- a/src/util/efirom.c
+++ b/src/util/efirom.c
@@ -81,6 +81,7 @@ static void read_pe_info ( void *pe, uint16_t *machine,
 	*machine = nt->nt32.FileHeader.Machine;
 	switch ( *machine ) {
 	case EFI_IMAGE_MACHINE_IA32:
+	case EFI_IMAGE_MACHINE_ARMTHUMB_MIXED:
 		*subsystem = nt->nt32.OptionalHeader.Subsystem;
 		break;
 	case EFI_IMAGE_MACHINE_X64:
diff --git a/src/util/elf2efi.c b/src/util/elf2efi.c
index 5e1050e3..01ddfd68 100644
--- a/src/util/elf2efi.c
+++ b/src/util/elf2efi.c
@@ -70,20 +70,14 @@
 
 #endif
 
-#define EFI_FILE_ALIGN 0x20
+#define ELF_MREL( mach, type ) ( (mach) | ( (type) << 16 ) )
 
-struct elf_machine {
-	unsigned int pe_machine;
-	unsigned int r_none;
-	unsigned int r_abs;
-	unsigned int r_pcrel;
-};
+#define EFI_FILE_ALIGN 0x20
 
 struct elf_file {
 	void *data;
 	size_t len;
 	const Elf_Ehdr *ehdr;
-	struct elf_machine *machine;
 };
 
 struct pe_section {
@@ -136,20 +130,6 @@ static struct pe_header efi_pe_header = {
 	},
 };
 
-static struct elf_machine machine_i386 = {
-	.pe_machine = EFI_IMAGE_MACHINE_IA32,
-	.r_none = R_386_NONE,
-	.r_abs = R_386_32,
-	.r_pcrel = R_386_PC32,
-};
-
-static struct elf_machine machine_x86_64 = {
-	.pe_machine = EFI_IMAGE_MACHINE_X64,
-	.r_none = R_X86_64_NONE,
-	.r_abs = R_X86_64_64,
-	.r_pcrel = R_X86_64_PC32,
-};
-
 /** Command-line options */
 struct options {
 	unsigned int subsystem;
@@ -355,19 +335,6 @@ static void read_elf_file ( const char *name, struct elf_file *elf ) {
 			exit ( 1 );
 		}
 	}
-
-	/* Identify architecture */
-	switch ( ehdr->e_machine ) {
-	case EM_386:
-		elf->machine = &machine_i386;
-		break;
-	case EM_X86_64:
-		elf->machine = &machine_x86_64;
-		break;
-	default:
-		eprintf ( "Unknown ELF architecture %d\n", ehdr->e_machine );
-		exit ( 1 );
-	}
 }
 
 /**
@@ -416,6 +383,36 @@ static const char * elf_string ( struct elf_file *elf, unsigned int section,
 }
 
 /**
+ * Set machine architecture
+ *
+ * @v elf		ELF file
+ * @v pe_header		PE file header
+ */
+static void set_machine ( struct elf_file *elf, struct pe_header *pe_header ) {
+	const Elf_Ehdr *ehdr = elf->ehdr;
+	uint16_t machine;
+
+	/* Identify machine architecture */
+	switch ( ehdr->e_machine ) {
+	case EM_386:
+		machine = EFI_IMAGE_MACHINE_IA32;
+		break;
+	case EM_X86_64:
+		machine = EFI_IMAGE_MACHINE_X64;
+		break;
+	case EM_ARM:
+		machine = EFI_IMAGE_MACHINE_ARMTHUMB_MIXED;
+		break;
+	default:
+		eprintf ( "Unknown ELF architecture %d\n", ehdr->e_machine );
+		exit ( 1 );
+	}
+
+	/* Set machine architecture */
+	pe_header->nt.FileHeader.Machine = machine;
+}
+
+/**
  * Process section
  *
  * @v elf		ELF file
@@ -568,6 +565,7 @@ static void process_reloc ( struct elf_file *elf, const Elf_Shdr *shdr,
 			    const Elf_Rel *rel, struct pe_relocs **pe_reltab ) {
 	unsigned int type = ELF_R_TYPE ( rel->r_info );
 	unsigned int sym = ELF_R_SYM ( rel->r_info );
+	unsigned int mrel = ELF_MREL ( elf->ehdr->e_machine, type );
 	size_t offset = ( shdr->sh_addr + rel->r_offset );
 
 	/* Look up symbol and process relocation */
@@ -579,18 +577,36 @@ static void process_reloc ( struct elf_file *elf, const Elf_Shdr *shdr,
 		/* Skip absolute symbols; the symbol value won't
 		 * change when the object is loaded.
 		 */
-	} else if ( type == elf->machine->r_none ) {
-		/* Ignore dummy relocations used by REQUIRE_SYMBOL() */
-	} else if ( type == elf->machine->r_abs ) {
-		/* Generate an 8-byte or 4-byte PE relocation */
-		generate_pe_reloc ( pe_reltab, offset, sizeof ( Elf_Addr ) );
-	} else if ( type == elf->machine->r_pcrel ) {
-		/* Skip PC-relative relocations; all relative offsets
-		 * remain unaltered when the object is loaded.
-		 */
 	} else {
-		eprintf ( "Unrecognised relocation type %d\n", type );
-		exit ( 1 );
+		switch ( mrel ) {
+		case ELF_MREL ( EM_386, R_386_NONE ) :
+		case ELF_MREL ( EM_ARM, R_ARM_NONE ) :
+		case ELF_MREL ( EM_X86_64, R_X86_64_NONE ) :
+			/* Ignore dummy relocations used by REQUIRE_SYMBOL() */
+			break;
+		case ELF_MREL ( EM_386, R_386_32 ) :
+		case ELF_MREL ( EM_ARM, R_ARM_ABS32 ) :
+			/* Generate a 4-byte PE relocation */
+			generate_pe_reloc ( pe_reltab, offset, 4 );
+			break;
+		case ELF_MREL ( EM_X86_64, R_X86_64_64 ) :
+			/* Generate an 8-byte PE relocation */
+			generate_pe_reloc ( pe_reltab, offset, 8 );
+			break;
+		case ELF_MREL ( EM_386, R_386_PC32 ) :
+		case ELF_MREL ( EM_ARM, R_ARM_CALL ) :
+		case ELF_MREL ( EM_ARM, R_ARM_THM_PC22 ) :
+		case ELF_MREL ( EM_ARM, R_ARM_THM_JUMP24 ) :
+		case ELF_MREL ( EM_X86_64, R_X86_64_PC32 ) :
+			/* Skip PC-relative relocations; all relative
+			 * offsets remain unaltered when the object is
+			 * loaded.
+			 */
+			break;
+		default:
+			eprintf ( "Unrecognised relocation type %d\n", type );
+			exit ( 1 );
+		}
 	}
 }
 
@@ -835,7 +851,7 @@ static void elf2pe ( const char *elf_name, const char *pe_name,
 
 	/* Initialise the PE header */
 	memcpy ( &pe_header, &efi_pe_header, sizeof ( pe_header ) );
-	pe_header.nt.FileHeader.Machine = elf.machine->pe_machine;
+	set_machine ( &elf, &pe_header );
 	pe_header.nt.OptionalHeader.AddressOfEntryPoint = elf.ehdr->e_entry;
 	pe_header.nt.OptionalHeader.Subsystem = opts->subsystem;