1 //===-- xray_AArch64.cc -----------------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file is a part of XRay, a dynamic runtime instrumentation system.
12 // Implementation of AArch64-specific routines (64-bit).
14 //===----------------------------------------------------------------------===//
15 #include "sanitizer_common/sanitizer_common.h"
16 #include "xray_defs.h"
17 #include "xray_interface_internal.h"
22 extern "C" void __clear_cache(void* start, void* end);
26 // The machine codes for some instructions used in runtime patching.
27 enum class PatchOpcodes : uint32_t {
28 PO_StpX0X30SP_m16e = 0xA9BF7BE0, // STP X0, X30, [SP, #-16]!
29 PO_LdrW0_12 = 0x18000060, // LDR W0, #12
30 PO_LdrX16_12 = 0x58000070, // LDR X16, #12
31 PO_BlrX16 = 0xD63F0200, // BLR X16
32 PO_LdpX0X30SP_16 = 0xA8C17BE0, // LDP X0, X30, [SP], #16
33 PO_B32 = 0x14000008 // B #32
36 inline static bool patchSled(const bool Enable, const uint32_t FuncId,
37 const XRaySledEntry &Sled,
38 void (*TracingHook)()) XRAY_NEVER_INSTRUMENT {
39 // When |Enable| == true,
40 // We replace the following compile-time stub (sled):
46 // With the following runtime patch:
49 // STP X0, X30, [SP, #-16]! ; PUSH {r0, lr}
50 // LDR W0, #12 ; W0 := function ID
51 // LDR X16,#12 ; X16 := address of the trampoline
53 // ;DATA: 32 bits of function ID
54 // ;DATA: lower 32 bits of the address of the trampoline
55 // ;DATA: higher 32 bits of the address of the trampoline
56 // LDP X0, X30, [SP], #16 ; POP {r0, lr}
58 // Replacement of the first 4-byte instruction should be the last and atomic
59 // operation, so that the user code which reaches the sled concurrently
60 // either jumps over the whole sled, or executes the whole sled when the
63 // When |Enable|==false, we set back the first instruction in the sled to be
66 uint32_t *FirstAddress = reinterpret_cast<uint32_t *>(Sled.Address);
67 uint32_t *CurAddress = FirstAddress + 1;
69 *CurAddress = uint32_t(PatchOpcodes::PO_LdrW0_12);
71 *CurAddress = uint32_t(PatchOpcodes::PO_LdrX16_12);
73 *CurAddress = uint32_t(PatchOpcodes::PO_BlrX16);
77 *reinterpret_cast<void (**)()>(CurAddress) = TracingHook;
79 *CurAddress = uint32_t(PatchOpcodes::PO_LdpX0X30SP_16);
81 std::atomic_store_explicit(
82 reinterpret_cast<std::atomic<uint32_t> *>(FirstAddress),
83 uint32_t(PatchOpcodes::PO_StpX0X30SP_m16e), std::memory_order_release);
85 std::atomic_store_explicit(
86 reinterpret_cast<std::atomic<uint32_t> *>(FirstAddress),
87 uint32_t(PatchOpcodes::PO_B32), std::memory_order_release);
89 __clear_cache(reinterpret_cast<char*>(FirstAddress),
90 reinterpret_cast<char*>(CurAddress));
94 bool patchFunctionEntry(const bool Enable, const uint32_t FuncId,
95 const XRaySledEntry &Sled,
96 void (*Trampoline)()) XRAY_NEVER_INSTRUMENT {
97 return patchSled(Enable, FuncId, Sled, Trampoline);
100 bool patchFunctionExit(const bool Enable, const uint32_t FuncId,
101 const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
102 return patchSled(Enable, FuncId, Sled, __xray_FunctionExit);
105 bool patchFunctionTailExit(const bool Enable, const uint32_t FuncId,
106 const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
107 return patchSled(Enable, FuncId, Sled, __xray_FunctionTailExit);
110 // FIXME: Maybe implement this better?
111 bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; }
113 } // namespace __xray
115 extern "C" void __xray_ArgLoggerEntry() XRAY_NEVER_INSTRUMENT {
116 // FIXME: this will have to be implemented in the trampoline assembly file