Shellcode testbed. Works on Debian 7

makefile

test: test.c test.h
	gcc -o test test.c

test.h: test.bin
	xxd -i test.bin > test.h

test.bin: test.s
	nasm -f bin -o test.bin test.s

clean:
	rm test.bin test.h test

.PHONY: clean

test.c

#include <sys/mman.h>
#include <unistd.h>

#include "test.h"

int main(void) {
    int (*func)();
    int *pageptr;
    int pagesize;

    pagesize = getpagesize();
    pageptr = test_bin - ((int)test_bin % pagesize);
    mprotect(pageptr, (test_bin_len/pagesize + 1)*pagesize, PROT_READ|PROT_EXEC);

    func = (int (*)())test_bin;
    (*func)();

    return 0;
}

test.s

SECTION .text

BITS 64

mov rax, 1
mov rbx, 1
int 0x80