1 //===-- xray_AArch64.cc -----------------------------------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is a part of XRay, a dynamic runtime instrumentation system.
11 //
12 // Implementation of AArch64-specific routines (64-bit).
13 //
14 //===----------------------------------------------------------------------===//
15 #include "sanitizer_common/sanitizer_common.h"
16 #include "xray_defs.h"
17 #include "xray_interface_internal.h"
18 #include <atomic>
19 #include <cassert>
20
21 extern "C" void __clear_cache(void *start, void *end);
22
23 namespace __xray {
24
25 // The machine codes for some instructions used in runtime patching.
26 enum class PatchOpcodes : uint32_t {
27 PO_StpX0X30SP_m16e = 0xA9BF7BE0, // STP X0, X30, [SP, #-16]!
28 PO_LdrW0_12 = 0x18000060, // LDR W0, #12
29 PO_LdrX16_12 = 0x58000070, // LDR X16, #12
30 PO_BlrX16 = 0xD63F0200, // BLR X16
31 PO_LdpX0X30SP_16 = 0xA8C17BE0, // LDP X0, X30, [SP], #16
32 PO_B32 = 0x14000008 // B #32
33 };
34
patchSled(const bool Enable,const uint32_t FuncId,const XRaySledEntry & Sled,void (* TracingHook)())35 inline static bool patchSled(const bool Enable, const uint32_t FuncId,
36 const XRaySledEntry &Sled,
37 void (*TracingHook)()) XRAY_NEVER_INSTRUMENT {
38 // When |Enable| == true,
39 // We replace the following compile-time stub (sled):
40 //
41 // xray_sled_n:
42 // B #32
43 // 7 NOPs (24 bytes)
44 //
45 // With the following runtime patch:
46 //
47 // xray_sled_n:
48 // STP X0, X30, [SP, #-16]! ; PUSH {r0, lr}
49 // LDR W0, #12 ; W0 := function ID
50 // LDR X16,#12 ; X16 := address of the trampoline
51 // BLR X16
52 // ;DATA: 32 bits of function ID
53 // ;DATA: lower 32 bits of the address of the trampoline
54 // ;DATA: higher 32 bits of the address of the trampoline
55 // LDP X0, X30, [SP], #16 ; POP {r0, lr}
56 //
57 // Replacement of the first 4-byte instruction should be the last and atomic
58 // operation, so that the user code which reaches the sled concurrently
59 // either jumps over the whole sled, or executes the whole sled when the
60 // latter is ready.
61 //
62 // When |Enable|==false, we set back the first instruction in the sled to be
63 // B #32
64
65 uint32_t *FirstAddress = reinterpret_cast<uint32_t *>(Sled.Address);
66 uint32_t *CurAddress = FirstAddress + 1;
67 if (Enable) {
68 *CurAddress = uint32_t(PatchOpcodes::PO_LdrW0_12);
69 CurAddress++;
70 *CurAddress = uint32_t(PatchOpcodes::PO_LdrX16_12);
71 CurAddress++;
72 *CurAddress = uint32_t(PatchOpcodes::PO_BlrX16);
73 CurAddress++;
74 *CurAddress = FuncId;
75 CurAddress++;
76 *reinterpret_cast<void (**)()>(CurAddress) = TracingHook;
77 CurAddress += 2;
78 *CurAddress = uint32_t(PatchOpcodes::PO_LdpX0X30SP_16);
79 CurAddress++;
80 std::atomic_store_explicit(
81 reinterpret_cast<std::atomic<uint32_t> *>(FirstAddress),
82 uint32_t(PatchOpcodes::PO_StpX0X30SP_m16e), std::memory_order_release);
83 } else {
84 std::atomic_store_explicit(
85 reinterpret_cast<std::atomic<uint32_t> *>(FirstAddress),
86 uint32_t(PatchOpcodes::PO_B32), std::memory_order_release);
87 }
88 __clear_cache(reinterpret_cast<char *>(FirstAddress),
89 reinterpret_cast<char *>(CurAddress));
90 return true;
91 }
92
patchFunctionEntry(const bool Enable,const uint32_t FuncId,const XRaySledEntry & Sled,void (* Trampoline)())93 bool patchFunctionEntry(const bool Enable, const uint32_t FuncId,
94 const XRaySledEntry &Sled,
95 void (*Trampoline)()) XRAY_NEVER_INSTRUMENT {
96 return patchSled(Enable, FuncId, Sled, Trampoline);
97 }
98
patchFunctionExit(const bool Enable,const uint32_t FuncId,const XRaySledEntry & Sled)99 bool patchFunctionExit(const bool Enable, const uint32_t FuncId,
100 const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
101 return patchSled(Enable, FuncId, Sled, __xray_FunctionExit);
102 }
103
patchFunctionTailExit(const bool Enable,const uint32_t FuncId,const XRaySledEntry & Sled)104 bool patchFunctionTailExit(const bool Enable, const uint32_t FuncId,
105 const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
106 return patchSled(Enable, FuncId, Sled, __xray_FunctionTailExit);
107 }
108
patchCustomEvent(const bool Enable,const uint32_t FuncId,const XRaySledEntry & Sled)109 bool patchCustomEvent(const bool Enable, const uint32_t FuncId,
110 const XRaySledEntry &Sled)
111 XRAY_NEVER_INSTRUMENT { // FIXME: Implement in aarch64?
112 return false;
113 }
114
patchTypedEvent(const bool Enable,const uint32_t FuncId,const XRaySledEntry & Sled)115 bool patchTypedEvent(const bool Enable, const uint32_t FuncId,
116 const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
117 // FIXME: Implement in aarch64?
118 return false;
119 }
120
121 // FIXME: Maybe implement this better?
probeRequiredCPUFeatures()122 bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; }
123
124 } // namespace __xray
125
__xray_ArgLoggerEntry()126 extern "C" void __xray_ArgLoggerEntry() XRAY_NEVER_INSTRUMENT {
127 // FIXME: this will have to be implemented in the trampoline assembly file
128 }
129