150 lines
3.2 KiB
C
150 lines
3.2 KiB
C
/*
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* Mesa 3-D graphics library
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*
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* Copyright (C) 1999-2005 Brian Paul All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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/**
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* \file glapi_execmem.c
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*
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* Function for allocating executable memory for dispatch stubs.
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*
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* Copied from main/execmem.c and simplified for dispatch stubs.
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*/
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#include "c11/threads.h"
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#include "u_execmem.h"
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#define EXEC_MAP_SIZE (4*1024)
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static mtx_t exec_mutex = _MTX_INITIALIZER_NP;
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static unsigned int head = 0;
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static unsigned char *exec_mem = (unsigned char *)0;
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#if defined(__linux__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__sun) || defined(__HAIKU__)
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#include <unistd.h>
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#include <sys/mman.h>
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#ifdef MESA_SELINUX
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#include <selinux/selinux.h>
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#endif
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#ifndef MAP_ANONYMOUS
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#define MAP_ANONYMOUS MAP_ANON
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#endif
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/*
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* Dispatch stubs are of fixed size and never freed. Thus, we do not need to
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* overlay a heap, we just mmap a page and manage through an index.
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*/
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static int
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init_map(void)
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{
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#ifdef MESA_SELINUX
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if (is_selinux_enabled()) {
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if (!security_get_boolean_active("allow_execmem") ||
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!security_get_boolean_pending("allow_execmem"))
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return 0;
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}
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#endif
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if (!exec_mem)
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exec_mem = mmap(NULL, EXEC_MAP_SIZE, PROT_EXEC | PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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return (exec_mem != MAP_FAILED);
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}
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#elif defined(_WIN32)
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#include <windows.h>
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/*
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* Avoid Data Execution Prevention.
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*/
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static int
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init_map(void)
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{
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exec_mem = VirtualAlloc(NULL, EXEC_MAP_SIZE, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
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return (exec_mem != NULL);
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}
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#else
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#include <stdlib.h>
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static int
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init_map(void)
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{
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exec_mem = malloc(EXEC_MAP_SIZE);
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return (exec_mem != NULL);
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}
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#endif
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void *
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u_execmem_alloc(unsigned int size)
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{
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#ifndef MESA_EXECMEM
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(void)size;
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return NULL;
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#else
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void *addr = NULL;
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mtx_lock(&exec_mutex);
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if (!init_map())
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goto bail;
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/* free space check, assumes no integer overflow */
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if (head + size > EXEC_MAP_SIZE)
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goto bail;
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/* allocation, assumes proper addr and size alignement */
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addr = exec_mem + head;
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head += size;
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bail:
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mtx_unlock(&exec_mutex);
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return addr;
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#endif /* MESA_EXECMEM */
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}
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