1/*
 2 Copyright 2013 Michael Pavone
 3 This file is part of BlastEm.
 4 BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
 5*/
 6#include <sys/mman.h>
 7#include <stddef.h>
 8#include <stdint.h>
 9#include <stdlib.h>
10#include <unistd.h>
11#include <errno.h>
12#include <stdio.h>
13
14#include "mem.h"
15#include "arena.h"
16#ifndef MAP_ANONYMOUS
17#define MAP_ANONYMOUS MAP_ANON
18#endif
19
20#ifndef MAP_32BIT
21#define MAP_32BIT 0
22#endif
23
24void * alloc_code(size_t *size)
25{
26	//start at the 1GB mark to allow plenty of room for sbrk based malloc implementations
27	//while still keeping well within 32-bit displacement range for calling code compiled into the executable
28	static uint8_t *next = (uint8_t *)0x40000000;
29	uint8_t *ret = try_alloc_arena();
30	if (ret) {
31		return ret;
32	}
33	if (*size & (PAGE_SIZE -1)) {
34		*size += PAGE_SIZE - (*size & (PAGE_SIZE - 1));
35	}
36	ret = mmap(next, *size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
37	if (ret == MAP_FAILED) {
38		perror("alloc_code");
39		return NULL;
40	}
41	track_block(ret);
42	next = ret + *size;
43	return ret;
44}
45