//===-------- xray_loongarch64.cpp ------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of XRay, a dynamic runtime instrumentation system.
//
// Implementation of loongarch-specific routines.
//
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_common.h"
#include "xray_defs.h"
#include "xray_interface_internal.h"
#include <atomic>
namespace __xray {
enum RegNum : uint32_t {
RN_RA = 1,
RN_SP = 3,
RN_T0 = 12,
RN_T1 = 13,
};
// Encode instructions in the 2RIx format, where the primary formats here
// are 2RI12-type and 2RI16-type.
static inline uint32_t
encodeInstruction2RIx(uint32_t Opcode, uint32_t Rd, uint32_t Rj,
uint32_t Imm) XRAY_NEVER_INSTRUMENT {
return Opcode | (Imm << 10) | (Rj << 5) | Rd;
}
// Encode instructions in 1RI20 format, e.g. lu12i.w/lu32i.d.
static inline uint32_t
encodeInstruction1RI20(uint32_t Opcode, uint32_t Rd,
uint32_t Imm) XRAY_NEVER_INSTRUMENT {
return Opcode | (Imm << 5) | Rd;
}
static inline bool patchSled(const bool Enable, const uint32_t FuncId,
const XRaySledEntry &Sled,
void (*TracingHook)()) XRAY_NEVER_INSTRUMENT {
// When |Enable| == true,
// We replace the following compile-time stub (sled):
//
// .Lxray_sled_beginN:
// B .Lxray_sled_endN
// 11 NOPs (44 bytes)
// .Lxray_sled_endN:
//
// With the following runtime patch:
//
// xray_sled_n:
// addi.d sp, sp, -16 ; create the stack frame
// st.d ra, sp, 8 ; save the return address
// lu12i.w t0, %abs_hi20(__xray_FunctionEntry/Exit)
// ori t0, t0, %abs_lo12(__xray_FunctionEntry/Exit)
// lu32i.d t0, %abs64_lo20(__xray_FunctionEntry/Exit)
// lu52i.d t0, t0, %abs64_hi12(__xray_FunctionEntry/Exit)
// lu12i.w t1, %abs_hi20(function_id)
// ori t1, t1, %abs_lo12(function_id) ; pass the function id
// jirl ra, t0, 0 ; call the tracing hook
// ld.d ra, sp, 8 ; restore the return address
// addi.d sp, sp, 16 ; de-allocate the stack frame
//
// Replacement of the first 4-byte instruction should be the last and atomic
// operation, so that the user code which reaches the sled concurrently
// either jumps over the whole sled, or executes the whole sled when the
// latter is ready.
//
// When |Enable|==false, we set the first instruction in the sled back to
// B #48
uint32_t *Address = reinterpret_cast<uint32_t *>(Sled.address());
if (Enable) {
uint32_t LoTracingHookAddr = reinterpret_cast<int64_t>(TracingHook) & 0xfff;
uint32_t HiTracingHookAddr =
(reinterpret_cast<int64_t>(TracingHook) >> 12) & 0xfffff;
uint32_t HigherTracingHookAddr =
(reinterpret_cast<int64_t>(TracingHook) >> 32) & 0xfffff;
uint32_t HighestTracingHookAddr =
(reinterpret_cast<int64_t>(TracingHook) >> 52) & 0xfff;
uint32_t LoFunctionID = FuncId & 0xfff;
uint32_t HiFunctionID = (FuncId >> 12) & 0xfffff;
Address[1] = encodeInstruction2RIx(0x29c00000, RegNum::RN_RA, RegNum::RN_SP,
0x8); // st.d ra, sp, 8
Address[2] = encodeInstruction1RI20(
0x14000000, RegNum::RN_T0,
HiTracingHookAddr); // lu12i.w t0, HiTracingHookAddr
Address[3] = encodeInstruction2RIx(
0x03800000, RegNum::RN_T0, RegNum::RN_T0,
LoTracingHookAddr); // ori t0, t0, LoTracingHookAddr
Address[4] = encodeInstruction1RI20(
0x16000000, RegNum::RN_T0,
HigherTracingHookAddr); // lu32i.d t0, HigherTracingHookAddr
Address[5] = encodeInstruction2RIx(
0x03000000, RegNum::RN_T0, RegNum::RN_T0,
HighestTracingHookAddr); // lu52i.d t0, t0, HighestTracingHookAddr
Address[6] =
encodeInstruction1RI20(0x14000000, RegNum::RN_T1,
HiFunctionID); // lu12i.w t1, HiFunctionID
Address[7] =
encodeInstruction2RIx(0x03800000, RegNum::RN_T1, RegNum::RN_T1,
LoFunctionID); // ori t1, t1, LoFunctionID
Address[8] = encodeInstruction2RIx(0x4c000000, RegNum::RN_RA, RegNum::RN_T0,
0); // jirl ra, t0, 0
Address[9] = encodeInstruction2RIx(0x28c00000, RegNum::RN_RA, RegNum::RN_SP,
0x8); // ld.d ra, sp, 8
Address[10] = encodeInstruction2RIx(
0x02c00000, RegNum::RN_SP, RegNum::RN_SP, 0x10); // addi.d sp, sp, 16
uint32_t CreateStackSpace = encodeInstruction2RIx(
0x02c00000, RegNum::RN_SP, RegNum::RN_SP, 0xff0); // addi.d sp, sp, -16
std::atomic_store_explicit(
reinterpret_cast<std::atomic<uint32_t> *>(Address), CreateStackSpace,
std::memory_order_release);
} else {
std::atomic_store_explicit(
reinterpret_cast<std::atomic<uint32_t> *>(Address),
uint32_t(0x50003000), std::memory_order_release); // b #48
}
return true;
}
bool patchFunctionEntry(const bool Enable, const uint32_t FuncId,
const XRaySledEntry &Sled,
void (*Trampoline)()) XRAY_NEVER_INSTRUMENT {
return patchSled(Enable, FuncId, Sled, Trampoline);
}
bool patchFunctionExit(const bool Enable, const uint32_t FuncId,
const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
return patchSled(Enable, FuncId, Sled, __xray_FunctionExit);
}
bool patchFunctionTailExit(const bool Enable, const uint32_t FuncId,
const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
// TODO: In the future we'd need to distinguish between non-tail exits and
// tail exits for better information preservation.
return patchSled(Enable, FuncId, Sled, __xray_FunctionExit);
}
bool patchCustomEvent(const bool Enable, const uint32_t FuncId,
const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
// FIXME: Implement in loongarch?
return false;
}
bool patchTypedEvent(const bool Enable, const uint32_t FuncId,
const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
// FIXME: Implement in loongarch?
return false;
}
} // namespace __xray
extern "C" void __xray_ArgLoggerEntry() XRAY_NEVER_INSTRUMENT {
// TODO: This will have to be implemented in the trampoline assembly file.
}
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