compiler-rt/lib/xray/xray_loongarch64.cpp

   1 //===-------- xray_loongarch64.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 loongarch-specific routines.
  12 //
  13 //===----------------------------------------------------------------------===//
  14 #include "sanitizer_common/sanitizer_common.h"
  15 #include "xray_defs.h"
  16 #include "xray_interface_internal.h"
  17 #include <atomic>
  18
  19 namespace __xray {
  20
  21 enum RegNum : uint32_t {
  22   RN_RA = 1,
  23   RN_SP = 3,
  24   RN_T0 = 12,
  25   RN_T1 = 13,
  26 };
  27
  28 // Encode instructions in the 2RIx format, where the primary formats here
  29 // are 2RI12-type and 2RI16-type.
  30 static inline uint32_t
  31 encodeInstruction2RIx(uint32_t Opcode, uint32_t Rd, uint32_t Rj,
  32                       uint32_t Imm) XRAY_NEVER_INSTRUMENT {
  33   return Opcode | (Imm << 10) | (Rj << 5) | Rd;
  34 }
  35
  36 // Encode instructions in 1RI20 format, e.g. lu12i.w/lu32i.d.
  37 static inline uint32_t
  38 encodeInstruction1RI20(uint32_t Opcode, uint32_t Rd,
  39                        uint32_t Imm) XRAY_NEVER_INSTRUMENT {
  40   return Opcode | (Imm << 5) | Rd;
  41 }
  42
  43 static inline bool patchSled(const bool Enable, const uint32_t FuncId,
  44                              const XRaySledEntry &Sled,
  45                              void (*TracingHook)()) XRAY_NEVER_INSTRUMENT {
  46   // When |Enable| == true,
  47   // We replace the following compile-time stub (sled):
  48   //
  49   // .Lxray_sled_beginN:
  50   //    B .Lxray_sled_endN
  51   //    11 NOPs (44 bytes)
  52   // .Lxray_sled_endN:
  53   //
  54   // With the following runtime patch:
  55   //
  56   // xray_sled_n:
  57   //   addi.d  sp, sp, -16                       ; create the stack frame
  58   //   st.d    ra, sp, 8                         ; save the return address
  59   //   lu12i.w t0, %abs_hi20(__xray_FunctionEntry/Exit)
  60   //   ori     t0, t0, %abs_lo12(__xray_FunctionEntry/Exit)
  61   //   lu32i.d t0, %abs64_lo20(__xray_FunctionEntry/Exit)
  62   //   lu52i.d t0, t0, %abs64_hi12(__xray_FunctionEntry/Exit)
  63   //   lu12i.w t1, %abs_hi20(function_id)
  64   //   ori     t1, t1, %abs_lo12(function_id)    ; pass the function id
  65   //   jirl    ra, t0, 0                         ; call the tracing hook
  66   //   ld.d    ra, sp, 8                         ; restore the return address
  67   //   addi.d  sp, sp, 16                        ; de-allocate the stack frame
  68   //
  69   // Replacement of the first 4-byte instruction should be the last and atomic
  70   // operation, so that the user code which reaches the sled concurrently
  71   // either jumps over the whole sled, or executes the whole sled when the
  72   // latter is ready.
  73   //
  74   // When |Enable|==false, we set the first instruction in the sled back to
  75   //   B #48
  76
  77   uint32_t *Address = reinterpret_cast<uint32_t *>(Sled.address());
  78   if (Enable) {
  79     uint32_t LoTracingHookAddr = reinterpret_cast<int64_t>(TracingHook) & 0xfff;
  80     uint32_t HiTracingHookAddr =
  81         (reinterpret_cast<int64_t>(TracingHook) >> 12) & 0xfffff;
  82     uint32_t HigherTracingHookAddr =
  83         (reinterpret_cast<int64_t>(TracingHook) >> 32) & 0xfffff;
  84     uint32_t HighestTracingHookAddr =
  85         (reinterpret_cast<int64_t>(TracingHook) >> 52) & 0xfff;
  86     uint32_t LoFunctionID = FuncId & 0xfff;
  87     uint32_t HiFunctionID = (FuncId >> 12) & 0xfffff;
  88     Address[1] = encodeInstruction2RIx(0x29c00000, RegNum::RN_RA, RegNum::RN_SP,
  89                                        0x8); // st.d ra, sp, 8
  90     Address[2] = encodeInstruction1RI20(
  91         0x14000000, RegNum::RN_T0,
  92         HiTracingHookAddr); // lu12i.w t0, HiTracingHookAddr
  93     Address[3] = encodeInstruction2RIx(
  94         0x03800000, RegNum::RN_T0, RegNum::RN_T0,
  95         LoTracingHookAddr); // ori t0, t0, LoTracingHookAddr
  96     Address[4] = encodeInstruction1RI20(
  97         0x16000000, RegNum::RN_T0,
  98         HigherTracingHookAddr); // lu32i.d t0, HigherTracingHookAddr
  99     Address[5] = encodeInstruction2RIx(
 100         0x03000000, RegNum::RN_T0, RegNum::RN_T0,
 101         HighestTracingHookAddr); // lu52i.d t0, t0, HighestTracingHookAddr
 102     Address[6] =
 103         encodeInstruction1RI20(0x14000000, RegNum::RN_T1,
 104                                HiFunctionID); // lu12i.w t1, HiFunctionID
 105     Address[7] =
 106         encodeInstruction2RIx(0x03800000, RegNum::RN_T1, RegNum::RN_T1,
 107                               LoFunctionID); // ori t1, t1, LoFunctionID
 108     Address[8] = encodeInstruction2RIx(0x4c000000, RegNum::RN_RA, RegNum::RN_T0,
 109                                        0); // jirl ra, t0, 0
 110     Address[9] = encodeInstruction2RIx(0x28c00000, RegNum::RN_RA, RegNum::RN_SP,
 111                                        0x8); // ld.d ra, sp, 8
 112     Address[10] = encodeInstruction2RIx(
 113         0x02c00000, RegNum::RN_SP, RegNum::RN_SP, 0x10); // addi.d sp, sp, 16
 114     uint32_t CreateStackSpace = encodeInstruction2RIx(
 115         0x02c00000, RegNum::RN_SP, RegNum::RN_SP, 0xff0); // addi.d sp, sp, -16
 116     std::atomic_store_explicit(
 117         reinterpret_cast<std::atomic<uint32_t> *>(Address), CreateStackSpace,
 118         std::memory_order_release);
 119   } else {
 120     std::atomic_store_explicit(
 121         reinterpret_cast<std::atomic<uint32_t> *>(Address),
 122         uint32_t(0x50003000), std::memory_order_release); // b #48
 123   }
 124   return true;
 125 }
 126
 127 bool patchFunctionEntry(const bool Enable, const uint32_t FuncId,
 128                         const XRaySledEntry &Sled,
 129                         void (*Trampoline)()) XRAY_NEVER_INSTRUMENT {
 130   return patchSled(Enable, FuncId, Sled, Trampoline);
 131 }
 132
 133 bool patchFunctionExit(const bool Enable, const uint32_t FuncId,
 134                        const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
 135   return patchSled(Enable, FuncId, Sled, __xray_FunctionExit);
 136 }
 137
 138 bool patchFunctionTailExit(const bool Enable, const uint32_t FuncId,
 139                            const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
 140   // TODO: In the future we'd need to distinguish between non-tail exits and
 141   // tail exits for better information preservation.
 142   return patchSled(Enable, FuncId, Sled, __xray_FunctionExit);
 143 }
 144
 145 bool patchCustomEvent(const bool Enable, const uint32_t FuncId,
 146                       const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
 147   // FIXME: Implement in loongarch?
 148   return false;
 149 }
 150
 151 bool patchTypedEvent(const bool Enable, const uint32_t FuncId,
 152                      const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
 153   // FIXME: Implement in loongarch?
 154   return false;
 155 }
 156 } // namespace __xray
 157
 158 extern "C" void __xray_ArgLoggerEntry() XRAY_NEVER_INSTRUMENT {
 159   // TODO: This will have to be implemented in the trampoline assembly file.
 160 }