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 21extern "C" void __clear_cache(void *start, void *end); 22 23namespace __xray { 24 25// The machine codes for some instructions used in runtime patching. 26enum 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 35inline 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 93bool 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 99bool 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 104bool 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 109bool 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 115bool 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? 122bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; } 123 124} // namespace __xray 125 126extern "C" void __xray_ArgLoggerEntry() XRAY_NEVER_INSTRUMENT { 127 // FIXME: this will have to be implemented in the trampoline assembly file 128} 129