2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2005 Brian Paul All Rights Reserved.
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23 * OTHER DEALINGS IN THE SOFTWARE.
28 * \file glapi_execmem.c
30 * Function for allocating executable memory for dispatch stubs.
32 * Copied from main/execmem.c and simplified for dispatch stubs.
36 #include "u_compiler.h"
38 #include "u_execmem.h"
41 #define EXEC_MAP_SIZE (4*1024)
43 u_mutex_declare_static(exec_mutex
);
45 static unsigned int head
= 0;
47 static unsigned char *exec_mem
= (unsigned char *)0;
50 #if defined(__linux__) || defined(__OpenBSD__) || defined(_NetBSD__) || defined(__sun) || defined(__HAIKU__)
56 #include <selinux/selinux.h>
61 #define MAP_ANONYMOUS MAP_ANON
66 * Dispatch stubs are of fixed size and never freed. Thus, we do not need to
67 * overlay a heap, we just mmap a page and manage through an index.
74 if (is_selinux_enabled()) {
75 if (!security_get_boolean_active("allow_execmem") ||
76 !security_get_boolean_pending("allow_execmem"))
82 exec_mem
= mmap(NULL
, EXEC_MAP_SIZE
, PROT_EXEC
| PROT_READ
| PROT_WRITE
,
83 MAP_PRIVATE
| MAP_ANONYMOUS
, -1, 0);
85 return (exec_mem
!= MAP_FAILED
);
95 * Avoid Data Execution Prevention.
101 exec_mem
= VirtualAlloc(NULL
, EXEC_MAP_SIZE
, MEM_COMMIT
, PAGE_EXECUTE_READWRITE
);
103 return (exec_mem
!= NULL
);
114 exec_mem
= malloc(EXEC_MAP_SIZE
);
116 return (exec_mem
!= NULL
);
123 u_execmem_alloc(unsigned int size
)
127 u_mutex_lock(exec_mutex
);
132 /* free space check, assumes no integer overflow */
133 if (head
+ size
> EXEC_MAP_SIZE
)
136 /* allocation, assumes proper addr and size alignement */
137 addr
= exec_mem
+ head
;
141 u_mutex_unlock(exec_mutex
);