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