57b08b0944
to reflect the new license. These used slightly different spellings that defeated my regular expressions. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351648
72 lines
2.1 KiB
C
72 lines
2.1 KiB
C
/* ===-- enable_execute_stack.c - Implement __enable_execute_stack ---------===
|
|
*
|
|
* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
* See https://llvm.org/LICENSE.txt for license information.
|
|
* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
*
|
|
* ===----------------------------------------------------------------------===
|
|
*/
|
|
|
|
#include "int_lib.h"
|
|
|
|
#ifndef _WIN32
|
|
#include <sys/mman.h>
|
|
#endif
|
|
|
|
/* #include "config.h"
|
|
* FIXME: CMake - include when cmake system is ready.
|
|
* Remove #define HAVE_SYSCONF 1 line.
|
|
*/
|
|
#define HAVE_SYSCONF 1
|
|
|
|
#ifdef _WIN32
|
|
#define WIN32_LEAN_AND_MEAN
|
|
#include <windows.h>
|
|
#else
|
|
#ifndef __APPLE__
|
|
#include <unistd.h>
|
|
#endif /* __APPLE__ */
|
|
#endif /* _WIN32 */
|
|
|
|
#if __LP64__
|
|
#define TRAMPOLINE_SIZE 48
|
|
#else
|
|
#define TRAMPOLINE_SIZE 40
|
|
#endif
|
|
|
|
/*
|
|
* The compiler generates calls to __enable_execute_stack() when creating
|
|
* trampoline functions on the stack for use with nested functions.
|
|
* It is expected to mark the page(s) containing the address
|
|
* and the next 48 bytes as executable. Since the stack is normally rw-
|
|
* that means changing the protection on those page(s) to rwx.
|
|
*/
|
|
|
|
COMPILER_RT_ABI void
|
|
__enable_execute_stack(void* addr)
|
|
{
|
|
|
|
#if _WIN32
|
|
MEMORY_BASIC_INFORMATION mbi;
|
|
if (!VirtualQuery (addr, &mbi, sizeof(mbi)))
|
|
return; /* We should probably assert here because there is no return value */
|
|
VirtualProtect (mbi.BaseAddress, mbi.RegionSize, PAGE_EXECUTE_READWRITE, &mbi.Protect);
|
|
#else
|
|
#if __APPLE__
|
|
/* On Darwin, pagesize is always 4096 bytes */
|
|
const uintptr_t pageSize = 4096;
|
|
#elif !defined(HAVE_SYSCONF)
|
|
#error "HAVE_SYSCONF not defined! See enable_execute_stack.c"
|
|
#else
|
|
const uintptr_t pageSize = sysconf(_SC_PAGESIZE);
|
|
#endif /* __APPLE__ */
|
|
|
|
const uintptr_t pageAlignMask = ~(pageSize-1);
|
|
uintptr_t p = (uintptr_t)addr;
|
|
unsigned char* startPage = (unsigned char*)(p & pageAlignMask);
|
|
unsigned char* endPage = (unsigned char*)((p+TRAMPOLINE_SIZE+pageSize) & pageAlignMask);
|
|
size_t length = endPage - startPage;
|
|
(void) mprotect((void *)startPage, length, PROT_READ | PROT_WRITE | PROT_EXEC);
|
|
#endif
|
|
}
|