1/* 2 * Mesa 3-D graphics library 3 * Version: 6.5 4 * 5 * Copyright (C) 1999-2005 Brian Paul All Rights Reserved. 6 * 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: 13 * 14 * The above copyright notice and this permission notice shall be included 15 * in all copies or substantial portions of the Software. 16 * 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 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN 21 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 */ 24 25 26/** 27 * \file glapi_execmem.c 28 * 29 * Function for allocating executable memory for dispatch stubs. 30 * 31 * Copied from main/execmem.c and simplified for dispatch stubs. 32 */ 33 34 35#include "u_compiler.h" 36#include "u_thread.h" 37#include "u_execmem.h" 38 39 40#define EXEC_MAP_SIZE (4*1024) 41 42u_mutex_declare_static(exec_mutex); 43 44static unsigned int head = 0; 45 46static unsigned char *exec_mem = (unsigned char *)0; 47 48 49#if defined(__linux__) || defined(__OpenBSD__) || defined(_NetBSD__) || defined(__sun) 50 51#include <unistd.h> 52#include <sys/mman.h> 53 54#ifdef MESA_SELINUX 55#include <selinux/selinux.h> 56#endif 57 58 59#ifndef MAP_ANONYMOUS 60#define MAP_ANONYMOUS MAP_ANON 61#endif 62 63 64/* 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. 67 */ 68 69static int 70init_map(void) 71{ 72#ifdef MESA_SELINUX 73 if (is_selinux_enabled()) { 74 if (!security_get_boolean_active("allow_execmem") || 75 !security_get_boolean_pending("allow_execmem")) 76 return 0; 77 } 78#endif 79 80 if (!exec_mem) 81 exec_mem = mmap(NULL, EXEC_MAP_SIZE, PROT_EXEC | PROT_READ | PROT_WRITE, 82 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 83 84 return (exec_mem != MAP_FAILED); 85} 86 87 88#elif defined(_WIN32) 89 90#include <windows.h> 91 92 93/* 94 * Avoid Data Execution Prevention. 95 */ 96 97static int 98init_map(void) 99{ 100 exec_mem = VirtualAlloc(NULL, EXEC_MAP_SIZE, MEM_COMMIT, PAGE_EXECUTE_READWRITE); 101 102 return (exec_mem != NULL); 103} 104 105 106#else 107 108#include <stdlib.h> 109 110static int 111init_map(void) 112{ 113 exec_mem = malloc(EXEC_MAP_SIZE); 114 115 return (exec_mem != NULL); 116} 117 118 119#endif 120 121void * 122u_execmem_alloc(unsigned int size) 123{ 124 void *addr = NULL; 125 126 u_mutex_lock(exec_mutex); 127 128 if (!init_map()) 129 goto bail; 130 131 /* free space check, assumes no integer overflow */ 132 if (head + size > EXEC_MAP_SIZE) 133 goto bail; 134 135 /* allocation, assumes proper addr and size alignement */ 136 addr = exec_mem + head; 137 head += size; 138 139bail: 140 u_mutex_unlock(exec_mutex); 141 142 return addr; 143} 144 145 146