1 //===-- hwasan_globals.h ----------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file is a part of HWAddressSanitizer.
10 //
11 // Private Hwasan header.
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef HWASAN_GLOBALS_H
15 #define HWASAN_GLOBALS_H
16 
17 #include <link.h>
18 
19 #include "sanitizer_common/sanitizer_common.h"
20 #include "sanitizer_common/sanitizer_internal_defs.h"
21 
22 namespace __hwasan {
23 // This object should only ever be casted over the global (i.e. not constructed)
24 // in the ELF PT_NOTE in order for `addr()` to work correctly.
25 struct hwasan_global {
26   // The size of this global variable. Note that the size in the descriptor is
27   // max 1 << 24. Larger globals have multiple descriptors.
sizehwasan_global28   uptr size() const { return info & 0xffffff; }
29   // The fully-relocated address of this global.
addrhwasan_global30   uptr addr() const { return reinterpret_cast<uintptr_t>(this) + gv_relptr; }
31   // The static tag of this global.
taghwasan_global32   u8 tag() const { return info >> 24; };
33 
34   // The relative address between the start of the descriptor for the HWASan
35   // global (in the PT_NOTE), and the fully relocated address of the global.
36   s32 gv_relptr;
37   u32 info;
38 };
39 
40 // Walk through the specific DSO (as specified by the base, phdr, and phnum),
41 // and return the range of the [beginning, end) of the HWASan globals descriptor
42 // array.
43 ArrayRef<const hwasan_global> HwasanGlobalsFor(ElfW(Addr) base,
44                                                const ElfW(Phdr) * phdr,
45                                                ElfW(Half) phnum);
46 
47 }  // namespace __hwasan
48 
49 #endif  // HWASAN_GLOBALS_H
50