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1 /**************************************************************************
2  *
3  * Copyright (C) 1999-2005  Brian Paul   All Rights Reserved.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9  * and/or sell copies of the Software, and to permit persons to whom the
10  * Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice shall be included
13  * in all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
16  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
19  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21  * OTHER DEALINGS IN THE SOFTWARE.
22  *
23  **************************************************************************/
24 
25 
26 /**
27  * \file exemem.c
28  * Functions for allocating executable memory.
29  *
30  * \author Keith Whitwell
31  */
32 
33 
34 #include "pipe/p_compiler.h"
35 #include "util/u_debug.h"
36 #include "os/os_thread.h"
37 #include "util/u_memory.h"
38 
39 #include "rtasm_execmem.h"
40 
41 #ifndef MAP_ANONYMOUS
42 #define MAP_ANONYMOUS MAP_ANON
43 #endif
44 
45 #if defined(PIPE_OS_WINDOWS)
46 #ifndef WIN32_LEAN_AND_MEAN
47 #define WIN32_LEAN_AND_MEAN 1
48 #endif
49 #include <windows.h>
50 #endif
51 
52 #if defined(PIPE_OS_UNIX)
53 
54 
55 /*
56  * Allocate a large block of memory which can hold code then dole it out
57  * in pieces by means of the generic memory manager code.
58  */
59 
60 #include <unistd.h>
61 #include <sys/mman.h>
62 #include "util/u_mm.h"
63 
64 #define EXEC_HEAP_SIZE (10*1024*1024)
65 
66 pipe_static_mutex(exec_mutex);
67 
68 static struct mem_block *exec_heap = NULL;
69 static unsigned char *exec_mem = NULL;
70 
71 
72 static int
init_heap(void)73 init_heap(void)
74 {
75    if (!exec_heap)
76       exec_heap = u_mmInit( 0, EXEC_HEAP_SIZE );
77 
78    if (!exec_mem)
79       exec_mem = (unsigned char *) mmap(0, EXEC_HEAP_SIZE,
80 					PROT_EXEC | PROT_READ | PROT_WRITE,
81 					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
82 
83    return (exec_mem != MAP_FAILED);
84 }
85 
86 
87 void *
rtasm_exec_malloc(size_t size)88 rtasm_exec_malloc(size_t size)
89 {
90    struct mem_block *block = NULL;
91    void *addr = NULL;
92 
93    pipe_mutex_lock(exec_mutex);
94 
95    if (!init_heap())
96       goto bail;
97 
98    if (exec_heap) {
99       size = (size + 31) & ~31;  /* next multiple of 32 bytes */
100       block = u_mmAllocMem( exec_heap, size, 5, 0 ); /* 5 -> 32-byte alignment */
101    }
102 
103    if (block)
104       addr = exec_mem + block->ofs;
105    else
106       debug_printf("rtasm_exec_malloc failed\n");
107 
108 bail:
109    pipe_mutex_unlock(exec_mutex);
110 
111    return addr;
112 }
113 
114 
115 void
rtasm_exec_free(void * addr)116 rtasm_exec_free(void *addr)
117 {
118    pipe_mutex_lock(exec_mutex);
119 
120    if (exec_heap) {
121       struct mem_block *block = u_mmFindBlock(exec_heap, (unsigned char *)addr - exec_mem);
122 
123       if (block)
124 	 u_mmFreeMem(block);
125    }
126 
127    pipe_mutex_unlock(exec_mutex);
128 }
129 
130 
131 #elif defined(PIPE_OS_WINDOWS)
132 
133 
134 /*
135  * Avoid Data Execution Prevention.
136  */
137 
138 void *
rtasm_exec_malloc(size_t size)139 rtasm_exec_malloc(size_t size)
140 {
141    return VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
142 }
143 
144 
145 void
rtasm_exec_free(void * addr)146 rtasm_exec_free(void *addr)
147 {
148    VirtualFree(addr, 0, MEM_RELEASE);
149 }
150 
151 
152 #else
153 
154 
155 /*
156  * Just use regular memory.
157  */
158 
159 void *
rtasm_exec_malloc(size_t size)160 rtasm_exec_malloc(size_t size)
161 {
162    return MALLOC( size );
163 }
164 
165 
166 void
rtasm_exec_free(void * addr)167 rtasm_exec_free(void *addr)
168 {
169    FREE(addr);
170 }
171 
172 
173 #endif
174