Index: src/OFInvocation.h
==================================================================
--- src/OFInvocation.h
+++ src/OFInvocation.h
@@ -20,10 +20,16 @@
 
 #ifdef OF_APPLE_RUNTIME
 # ifdef OF_X86_64
 #  define OF_INVOCATION_CAN_INVOKE
 # endif
+#else
+# ifdef OF_ELF
+#  ifdef OF_X86_64
+#   define OF_INVOCATION_CAN_INVOKE
+#  endif
+# endif
 #endif
 
 @class OFMethodSignature;
 @class OFMutableArray OF_GENERIC(ObjectType);
 @class OFMutableData;

Index: src/invocation/Makefile
==================================================================
--- src/invocation/Makefile
+++ src/invocation/Makefile
@@ -7,6 +7,6 @@
        invoke.m
 
 include ../../buildsys.mk
 
 ASFLAGS += -I../.. -I..
-OBJCFLAGS += -I../.. -I.. -I../exceptions
+OBJCFLAGS += -I../.. -I.. -I../exceptions -I../runtime

ADDED   src/invocation/call-x86_64-elf.S
Index: src/invocation/call-x86_64-elf.S
==================================================================
--- src/invocation/call-x86_64-elf.S
+++ src/invocation/call-x86_64-elf.S
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017
+ *   Jonathan Schleifer <js@heap.zone>
+ *
+ * All rights reserved.
+ *
+ * This file is part of ObjFW. It may be distributed under the terms of the
+ * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
+ * the packaging of this file.
+ *
+ * Alternatively, it may be distributed under the terms of the GNU General
+ * Public License, either version 2 or 3, which can be found in the file
+ * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
+ * file.
+ */
+
+#include "config.h"
+
+.globl of_invocation_call
+
+.section .text
+of_invocation_call:
+	pushq	%rbp
+	movq	%rsp, %rbp
+
+	subq	$16, %rsp
+	andq	$-16, %rsp
+	movq	%rdi, -8(%rbp)
+
+	movb	225(%rdi), %r11b
+	cmpb	$1, %r11b
+	je	.lookup_stret
+	cmpb	$4, %r11b
+	je	.lookup_stret
+
+	movq	8(%rdi), %rsi
+	movq	0(%rdi), %rdi
+	call	objc_msg_lookup@PLT
+
+.after_lookup:
+	movq	%rax, -16(%rbp)
+	movq	-8(%rbp), %rdi
+
+	leaq	240(%rdi), %rdx
+	movq	232(%rdi), %rcx
+
+	testq	$1, %rcx
+	jnz	.fix_align
+
+.fill_stack:
+	testq	%rcx, %rcx
+	jz	.stack_filled
+
+	decq	%rcx
+	movq	(%rdx,%rcx,8), %r11
+	pushq	%r11
+
+	jmp	.fill_stack
+
+.stack_filled:
+	movb	224(%rdi), %al
+
+	movdqa	176(%rdi), %xmm7
+	movdqa	160(%rdi), %xmm6
+	movdqa	144(%rdi), %xmm5
+	movdqa	128(%rdi), %xmm4
+	movdqa	112(%rdi), %xmm3
+	movdqa	96(%rdi), %xmm2
+	movdqa	80(%rdi), %xmm1
+	movdqa	64(%rdi), %xmm0
+
+	movq	40(%rdi), %r9
+	movq	32(%rdi), %r8
+	movq	24(%rdi), %rcx
+	movq	16(%rdi), %rdx
+	movq	8(%rdi), %rsi
+	movq	0(%rdi), %rdi
+
+	movq	-16(%rbp), %r11
+
+	cmpb	$3, 225(%rdi)
+	je	.jmp_r11
+	cmpb	$4, 225(%rdi)
+	je	.jmp_r11
+
+	call	*%r11
+
+.after_send:
+	movq	-8(%rbp), %rdi
+	movq	%rax, 48(%rdi)
+	movq	%rdx, 56(%rdi)
+	movdqa	%xmm0, 64(%rdi)
+	movdqa	%xmm1, 80(%rdi)
+
+	cmpb	$2, 225(%rdi)
+	je	.pop_long_double
+
+.return:
+	movq	%rbp, %rsp
+	popq	%rbp
+
+	ret
+
+.fix_align:
+	xorq	%r11, %r11
+	pushq	%r11
+	jmp	.fill_stack
+
+.lookup_stret:
+	movq	16(%rdi), %rsi
+	movq	8(%rdi), %rdi
+	call	objc_msg_lookup_stret@PLT
+
+	jmp	.after_lookup
+
+.jmp_r11:
+	jmp	*%r11
+
+.pop_long_double:
+	fstpt	192(%rdi)
+	jmp	.return
+
+#ifdef OF_LINUX
+.section .note.GNU-stack, "", %progbits
+#endif

Index: src/invocation/call.S
==================================================================
--- src/invocation/call.S
+++ src/invocation/call.S
@@ -17,9 +17,15 @@
 #include "config.h"
 
 #include "platform.h"
 
 #ifdef OF_APPLE_RUNTIME
-# if defined(OF_X86_64)
+# ifdef OF_X86_64
 #  include "apple-call-x86_64.S"
 # endif
+#else
+# ifdef OF_ELF
+#  ifdef OF_X86_64
+#   include "call-x86_64-elf.S"
+#  endif
+# endif
 #endif

Index: src/invocation/invoke.m
==================================================================
--- src/invocation/invoke.m
+++ src/invocation/invoke.m
@@ -16,13 +16,11 @@
 
 #include "config.h"
 
 #include "platform.h"
 
-#ifdef OF_X86_64
-# ifdef OF_APPLE_RUNTIME
-#  include "invoke-x86_64.m"
-# endif
+#if defined(OF_X86_64) && (defined(OF_APPLE_RUNTIME) || defined(OF_ELF))
+# include "invoke-x86_64.m"
 #else
 /* To not have an empty translation unit otherwise */
 int of_invocation_cannot_invoke;
 #endif