2 * Mesa 3-D graphics library
4 * Copyright (C) 1999-2005 Brian Paul All Rights Reserved.
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 * OTHER DEALINGS IN THE SOFTWARE.
27 * \file glapi_execmem.c
29 * Function for allocating executable memory for dispatch stubs.
31 * Copied from main/execmem.c and simplified for dispatch stubs.
35 #include "c99_compat.h"
36 #include "c11/threads.h"
37 #include "u_execmem.h"
40 #define EXEC_MAP_SIZE (4*1024)
42 static mtx_t exec_mutex
= _MTX_INITIALIZER_NP
;
44 static unsigned int head
= 0;
46 static unsigned char *exec_mem
= (unsigned char *)0;
49 #if defined(__linux__) || defined(__OpenBSD__) || defined(_NetBSD__) || defined(__sun) || defined(__HAIKU__)
55 #include <selinux/selinux.h>
60 #define MAP_ANONYMOUS MAP_ANON
65 * Dispatch stubs are of fixed size and never freed. Thus, we do not need to
66 * overlay a heap, we just mmap a page and manage through an index.
73 if (is_selinux_enabled()) {
74 if (!security_get_boolean_active("allow_execmem") ||
75 !security_get_boolean_pending("allow_execmem"))
81 exec_mem
= mmap(NULL
, EXEC_MAP_SIZE
, PROT_EXEC
| PROT_READ
| PROT_WRITE
,
82 MAP_PRIVATE
| MAP_ANONYMOUS
, -1, 0);
84 return (exec_mem
!= MAP_FAILED
);
94 * Avoid Data Execution Prevention.
100 exec_mem
= VirtualAlloc(NULL
, EXEC_MAP_SIZE
, MEM_COMMIT
, PAGE_EXECUTE_READWRITE
);
102 return (exec_mem
!= NULL
);
113 exec_mem
= malloc(EXEC_MAP_SIZE
);
115 return (exec_mem
!= NULL
);
122 u_execmem_alloc(unsigned int size
)
126 mtx_lock(&exec_mutex
);
131 /* free space check, assumes no integer overflow */
132 if (head
+ size
> EXEC_MAP_SIZE
)
135 /* allocation, assumes proper addr and size alignement */
136 addr
= exec_mem
+ head
;
140 mtx_unlock(&exec_mutex
);