FEX-Emu--FEX/Source/Tools/LinuxEmulation/LinuxSyscalls/Syscalls/Thread.cpp

// SPDX-License-Identifier: MIT
/*
$info$
tags: LinuxSyscalls|syscalls-shared
$end_info$
*/

#include "CodeLoader.h"

#include "LinuxSyscalls/SignalDelegator.h"
#include "LinuxSyscalls/Syscalls.h"
#include "LinuxSyscalls/Syscalls/Thread.h"
#include "LinuxSyscalls/x64/Syscalls.h"
#include "LinuxSyscalls/x64/Thread.h"
#include "LinuxSyscalls/x32/Syscalls.h"
#include "LinuxSyscalls/x32/Thread.h"
#include "LinuxSyscalls/Utils/Threads.h"

#include <FEXCore/Core/Context.h>
#include <FEXCore/Core/X86Enums.h>
#include <FEXCore/Debug/InternalThreadState.h>
#include <FEXCore/IR/IR.h>
#include <FEXCore/Utils/Allocator.h>
#include <FEXCore/Utils/Event.h>

#include <FEXHeaderUtils/Syscalls.h>

#include <grp.h>
#include <limits.h>
#include <linux/futex.h>
#include <linux/seccomp.h>
#include <linux/sched.h>
#include <stdint.h>
#include <sched.h>
#include <sys/personality.h>
#include <sys/poll.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <unistd.h>
#include <sys/fsuid.h>

ARG_TO_STR(idtype_t, "%u")

namespace FEX::HLE {

struct ExecutionThreadHandler {
  FEXCore::Context::Context* CTX;
  FEX::HLE::ThreadStateObject* Thread;
  Event ThreadWaiting {};

  // Pause on thread start handling.
  FEXCore::InterruptableConditionVariable StartRunningCV {};
  FEXCore::InterruptableConditionVariable StartRunningResponse {};
};

static void* ThreadHandler(void* Data) {
  ExecutionThreadHandler* Handler = reinterpret_cast<ExecutionThreadHandler*>(Data);
  auto CTX = Handler->CTX;
  auto Thread = Handler->Thread;

  Thread->ThreadInfo.PID = ::getpid();
  Thread->ThreadInfo.TID = FHU::Syscalls::gettid();
  if (Thread->Thread->ThreadStats) {
    Thread->Thread->ThreadStats->TID.store(Thread->ThreadInfo.TID, std::memory_order_relaxed);
  }

  FEXCore::Allocator::InitializeThread();

  FEX::HLE::_SyscallHandler->RegisterTLSState(Thread);

  // Now notify the thread that we are initialized
  Handler->ThreadWaiting.NotifyOne();

  Handler->StartRunningCV.Wait();

  // Notify the parent thread that it can continue.
  // Handler is a stack object on the parent thread, and will be invalid after notification.
  Handler->StartRunningResponse.NotifyOne();

  CTX->ExecuteThread(Thread->Thread);
  FEX::HLE::_SyscallHandler->UninstallTLSState(Thread);
  FEX::HLE::_SyscallHandler->TM.DestroyThread(Thread);
  return nullptr;
}

FEX::HLE::ThreadStateObject* CreateNewThread(FEXCore::Context::Context* CTX, FEXCore::Core::CpuStateFrame* Frame, FEX::HLE::clone3_args* args) {
  uint64_t flags = args->args.flags;
  auto NewThread = FEX::HLE::_SyscallHandler->TM.CreateThread(0, 0, &Frame->State, args->args.parent_tid,
                                                              FEX::HLE::ThreadManager::GetStateObjectFromCPUState(Frame));

  NewThread->Thread->CurrentFrame->State.gregs[FEXCore::X86State::REG_RAX] = 0;
  if (args->Type == TYPE_CLONE3) {
    // stack pointer points to the lowest address to the stack
    // set RSP to stack + size
    NewThread->Thread->CurrentFrame->State.gregs[FEXCore::X86State::REG_RSP] = args->args.stack + args->args.stack_size;
  } else {
    NewThread->Thread->CurrentFrame->State.gregs[FEXCore::X86State::REG_RSP] = args->args.stack;
  }

  if (FEX::HLE::_SyscallHandler->Is64BitMode()) {
    if (flags & CLONE_SETTLS) {
      x64::SetThreadArea(NewThread->Thread->CurrentFrame, reinterpret_cast<void*>(args->args.tls));
    }
    // Set us to start just after the syscall instruction
    x64::AdjustRipForNewThread(NewThread->Thread->CurrentFrame);
  } else {
    if (flags & CLONE_SETTLS) {
      x32::SetThreadArea(NewThread->Thread->CurrentFrame, reinterpret_cast<void*>(args->args.tls));
    }
    x32::AdjustRipForNewThread(NewThread->Thread->CurrentFrame);
  }

  // Initialize a new thread for execution.
  ExecutionThreadHandler Arg {
    .CTX = CTX,
    .Thread = NewThread,
  };
  NewThread->ExecutionThread = FEXCore::Threads::Thread::Create(ThreadHandler, &Arg);

  // Wait for the thread to have started.
  Arg.ThreadWaiting.Wait();

  if (FEX::HLE::_SyscallHandler->NeedXIDCheck()) {
    // The first time an application creates a thread, GLIBC installs their SETXID signal handler.
    // FEX needs to capture all signals and defer them to the guest.
    // Once FEX creates its first guest thread, overwrite the GLIBC SETXID handler *again* to ensure
    // FEX maintains control of the signal handler on this signal.
    FEX::HLE::_SyscallHandler->GetSignalDelegator()->CheckXIDHandler();
    FEX::HLE::_SyscallHandler->DisableXIDCheck();
  }

  // Return the new threads TID
  uint64_t Result = NewThread->ThreadInfo.TID;

  // Sets the child TID to pointer in ParentTID
  if (flags & CLONE_PARENT_SETTID) {
    *reinterpret_cast<pid_t*>(args->args.parent_tid) = Result;
  }

  // Sets the child TID to the pointer in ChildTID
  if (flags & CLONE_CHILD_SETTID) {
    NewThread->ThreadInfo.set_child_tid = reinterpret_cast<int32_t*>(args->args.child_tid);
    *reinterpret_cast<pid_t*>(args->args.child_tid) = Result;
  }

  // When the thread exits, clear the child thread ID at ChildTID
  // Additionally wakeup a futex at that address
  // Address /may/ be changed with SET_TID_ADDRESS syscall
  if (flags & CLONE_CHILD_CLEARTID) {
    NewThread->ThreadInfo.clear_child_tid = reinterpret_cast<int32_t*>(args->args.child_tid);
  }

  // clone3 flag
  if (flags & CLONE_PIDFD) {
    // Use pidfd_open to emulate this flag
    const int pidfd = ::syscall(SYSCALL_DEF(pidfd_open), Result, 0);
    if (Result == ~0ULL) {
      LogMan::Msg::EFmt("Couldn't get pidfd of TID {}\n", Result);
    } else {
      *reinterpret_cast<int*>(args->args.pidfd) = pidfd;
    }
  }

  FEX::HLE::_SyscallHandler->TM.TrackThread(NewThread);

  // Start running the thread
  Arg.StartRunningCV.NotifyOne();

  // Wait for the thread to start running.
  Arg.StartRunningResponse.Wait();

  return NewThread;
}

uint64_t HandleNewClone(FEX::HLE::ThreadStateObject* Thread, FEXCore::Context::Context* CTX, FEXCore::Core::CpuStateFrame* Frame,
                        FEX::HLE::clone3_args* CloneArgs) {
  FEXCore::Allocator::InitializeThread();
  auto GuestArgs = &CloneArgs->args;
  uint64_t flags = GuestArgs->flags;
  auto NewThread = Thread;
  bool CreatedNewThreadObject {};

  if (flags & CLONE_THREAD) {
    // Overwrite thread
    NewThread = FEX::HLE::_SyscallHandler->TM.CreateThread(0, 0, &Frame->State, GuestArgs->parent_tid,
                                                           FEX::HLE::ThreadManager::GetStateObjectFromCPUState(Frame));

    NewThread->Thread->CurrentFrame->State.gregs[FEXCore::X86State::REG_RAX] = 0;
    if (GuestArgs->stack == 0) {
      // Copies in the original thread's stack
    } else {
      NewThread->Thread->CurrentFrame->State.gregs[FEXCore::X86State::REG_RSP] = GuestArgs->stack;
    }

    // CLONE_PARENT_SETTID, CLONE_CHILD_SETTID, CLONE_CHILD_CLEARTID, CLONE_PIDFD will be handled by kernel
    // Call execution thread directly since we already are on the new thread
    CreatedNewThreadObject = true;
  } else {
    // If we don't have CLONE_THREAD then we are effectively a fork
    // Clear all the other threads that are being tracked
    // Frame->Thread is /ONLY/ safe to access when CLONE_THREAD flag is not set
    // Unlock the mutexes on both sides of the fork
    FEX::HLE::_SyscallHandler->UnlockAfterFork(Frame->Thread, true);

    ::syscall(SYS_rt_sigprocmask, SIG_SETMASK, &CloneArgs->SignalMask, nullptr, sizeof(CloneArgs->SignalMask));

    Thread->Thread->CurrentFrame->State.gregs[FEXCore::X86State::REG_RAX] = 0;
    if (GuestArgs->stack == 0) {
      // Copies in the original thread's stack
    } else {
      Thread->Thread->CurrentFrame->State.gregs[FEXCore::X86State::REG_RSP] = GuestArgs->stack;
    }
  }

  if (CloneArgs->Type == TYPE_CLONE3) {
    // If we are coming from a clone3 handler then we need to adjust RSP.
    Thread->Thread->CurrentFrame->State.gregs[FEXCore::X86State::REG_RSP] += CloneArgs->args.stack_size;
  }

  if (FEX::HLE::_SyscallHandler->Is64BitMode()) {
    if (flags & CLONE_SETTLS) {
      x64::SetThreadArea(NewThread->Thread->CurrentFrame, reinterpret_cast<void*>(GuestArgs->tls));
    }
    // Set us to start just after the syscall instruction
    x64::AdjustRipForNewThread(NewThread->Thread->CurrentFrame);
  } else {
    if (flags & CLONE_SETTLS) {
      x32::SetThreadArea(NewThread->Thread->CurrentFrame, reinterpret_cast<void*>(GuestArgs->tls));
    }
    x32::AdjustRipForNewThread(NewThread->Thread->CurrentFrame);
  }

  // Depending on clone settings, our TID and PID could have changed
  Thread->ThreadInfo.TID = FHU::Syscalls::gettid();
  Thread->ThreadInfo.PID = ::getpid();
  FEX::HLE::_SyscallHandler->FM.UpdatePID(Thread->ThreadInfo.PID);

  if (CreatedNewThreadObject) {
    FEX::HLE::_SyscallHandler->TM.TrackThread(Thread);
  }

  FEX::HLE::_SyscallHandler->RegisterTLSState(Thread);

  // Start exuting the thread directly
  // Our host clone starts in a new stack space, so it can't return back to the JIT space
  CTX->ExecuteThread(Thread->Thread);

  FEX::HLE::_SyscallHandler->UninstallTLSState(Thread);

  // The rest of the context remains as is and the thread will continue executing
  return Thread->StatusCode;
}

static int CloneFork(uint32_t flags, uint64_t exit_signal) {
  return ::syscall(SYSCALL_DEF(clone), (flags & (CLONE_FS | CLONE_FILES)) | exit_signal, nullptr, nullptr, nullptr, nullptr);
}

uint64_t ForkGuest(FEXCore::Core::InternalThreadState* Thread, FEXCore::Core::CpuStateFrame* Frame, FEX::HLE::clone3_args* args) {
  const uint64_t flags = args->args.flags;
  auto stack = reinterpret_cast<const void*>(args->args.stack);
  const uint64_t stack_size = args->args.stack_size;
  auto parent_tid = reinterpret_cast<pid_t*>(args->args.parent_tid);
  auto child_tid = reinterpret_cast<pid_t*>(args->args.child_tid);
  auto tls = reinterpret_cast<void*>(args->args.tls);
  const uint64_t exit_signal = args->args.exit_signal;

  // Sanity check flags here.
  if (args->Type == TypeOfClone::TYPE_CLONE3) {
    constexpr uint64_t UnsupportedFlags = CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP | CLONE_NEWTIME;
    if (args->args.flags & UnsupportedFlags) {
      LogMan::Msg::EFmt("fork: Unsupported flags passed. {:#x}", args->args.flags & UnsupportedFlags);
    }
  }

  // Just before we fork, we lock all syscall mutexes so that both processes will end up with a locked mutex
  uint64_t Mask {~0ULL};
  ::syscall(SYS_rt_sigprocmask, SIG_SETMASK, &Mask, &Mask, sizeof(Mask));

  FEX::HLE::_SyscallHandler->LockBeforeFork(Frame->Thread);

  const bool IsVFork = flags & CLONE_VFORK;
  pid_t Result {};
  int VForkFDs[2];
  if (IsVFork) {
    // Use pipes as a mechanism for knowing when the child process is exiting.
    // FEX can't use `waitpid` for this since the child process may want to use it.
    // If we use `waitpid` then the kernel won't return the same data if asked again.
    pipe2(VForkFDs, O_CLOEXEC);

    // XXX: We don't currently support a real `vfork` as it causes problems.
    // Currently behaves like a fork (with wait after the fact), which isn't correct. Need to find where the problem is
    Result = CloneFork(flags, exit_signal);

    if (Result == 0) {
      // Close the read end of the pipe.
      // Keep the write end open so the parent can poll it.
      close(VForkFDs[0]);
    } else {
      // Close the write end of the pipe.
      close(VForkFDs[1]);
    }
  } else {
    Result = CloneFork(flags, exit_signal);
  }
  const bool IsChild = Result == 0;

  if (IsChild) {
    auto ThreadObject = static_cast<FEX::HLE::ThreadStateObject*>(Thread->FrontendPtr);
    // Unlock the mutexes on both sides of the fork
    FEX::HLE::_SyscallHandler->UnlockAfterFork(Frame->Thread, IsChild);

    ::syscall(SYS_rt_sigprocmask, SIG_SETMASK, &Mask, nullptr, sizeof(Mask));

    // Child
    // update the internal TID
    ThreadObject->ThreadInfo.TID = FHU::Syscalls::gettid();
    ThreadObject->ThreadInfo.PID = ::getpid();
    FEX::HLE::_SyscallHandler->FM.UpdatePID(ThreadObject->ThreadInfo.PID);
    ThreadObject->ThreadInfo.clear_child_tid = nullptr;

    // only a  single thread running so no need to remove anything from the thread array

    // Handle child setup now
    if (stack != nullptr) {
      // use specified stack
      Frame->State.gregs[FEXCore::X86State::REG_RSP] = reinterpret_cast<uint64_t>(stack) + stack_size;
    } else {
      // In the case of fork and nullptr stack then the child uses the same stack space as the parent
      // Same virtual address, different addressspace
    }

    if (FEX::HLE::_SyscallHandler->Is64BitMode()) {
      if (flags & CLONE_SETTLS) {
        x64::SetThreadArea(Frame, tls);
      }
    } else {
      // 32bit TLS doesn't just set the fs register
      if (flags & CLONE_SETTLS) {
        x32::SetThreadArea(Frame, tls);
      }
    }

    // Sets the child TID to the pointer in ChildTID
    if (flags & CLONE_CHILD_SETTID) {
      ThreadObject->ThreadInfo.set_child_tid = child_tid;
      *child_tid = ThreadObject->ThreadInfo.TID;
    }

    // When the thread exits, clear the child thread ID at ChildTID
    // Additionally wakeup a futex at that address
    // Address /may/ be changed with SET_TID_ADDRESS syscall
    if (flags & CLONE_CHILD_CLEARTID) {
      ThreadObject->ThreadInfo.clear_child_tid = child_tid;
    }

    // the rest of the context remains as is, this thread will keep executing
    return 0;
  } else {
    if (Result != -1) {
      if (flags & CLONE_PARENT_SETTID) {
        *parent_tid = Result;
      }
    }

    // Unlock the mutexes on both sides of the fork
    FEX::HLE::_SyscallHandler->UnlockAfterFork(Frame->Thread, IsChild);

    ::syscall(SYS_rt_sigprocmask, SIG_SETMASK, &Mask, nullptr, sizeof(Mask));

    // VFork needs the parent to wait for the child to exit.
    if (IsVFork) {
      // Wait for the read end of the pipe to close.
      pollfd PollFD {};
      PollFD.fd = VForkFDs[0];
      PollFD.events = POLLIN | POLLOUT | POLLRDHUP | POLLERR | POLLHUP | POLLNVAL;

      // Mask all signals until the child process returns.
      sigset_t SignalMask {};
      sigfillset(&SignalMask);
      while (ppoll(&PollFD, 1, nullptr, &SignalMask) == -1 && errno == EINTR)
        ;

      // Close the read end now.
      close(VForkFDs[0]);
    }

    // Parent
    SYSCALL_ERRNO();
  }
}

void RegisterThread(FEX::HLE::SyscallHandler* Handler) {
  using namespace FEXCore::IR;

  REGISTER_SYSCALL_IMPL(rt_sigreturn, [](FEXCore::Core::CpuStateFrame* Frame) -> uint64_t {
    FEX::HLE::_SyscallHandler->GetSignalDelegator()->HandleSignalHandlerReturn(true);
    FEX_UNREACHABLE;
  });

  REGISTER_SYSCALL_IMPL(fork, ([](FEXCore::Core::CpuStateFrame* Frame) -> uint64_t {
                          FEX::HLE::clone3_args args {.Type = TypeOfClone::TYPE_CLONE2,
                                                      .args = {
                                                        .flags = 0,
                                                        .pidfd = 0,
                                                        .child_tid = 0,
                                                        .parent_tid = 0,
                                                        .exit_signal = SIGCHLD,
                                                        .stack = 0,
                                                        .stack_size = 0,
                                                        .tls = 0,
                                                        .set_tid = 0,
                                                        .set_tid_size = 0,
                                                        .cgroup = 0,
                                                      }};

                          return ForkGuest(Frame->Thread, Frame, &args);
                        }));

  REGISTER_SYSCALL_IMPL(vfork, ([](FEXCore::Core::CpuStateFrame* Frame) -> uint64_t {
                          FEX::HLE::clone3_args args {.Type = TypeOfClone::TYPE_CLONE2,
                                                      .args = {
                                                        .flags = CLONE_VFORK,
                                                        .pidfd = 0,
                                                        .child_tid = 0,
                                                        .parent_tid = 0,
                                                        .exit_signal = SIGCHLD,
                                                        .stack = 0,
                                                        .stack_size = 0,
                                                        .tls = 0,
                                                        .set_tid = 0,
                                                        .set_tid_size = 0,
                                                        .cgroup = 0,
                                                      }};

                          return ForkGuest(Frame->Thread, Frame, &args);
                        }));

  REGISTER_SYSCALL_IMPL(getpgrp, [](FEXCore::Core::CpuStateFrame* Frame) -> uint64_t {
    uint64_t Result = ::getpgrp();
    SYSCALL_ERRNO();
  });

  REGISTER_SYSCALL_IMPL(clone3, ([](FEXCore::Core::CpuStateFrame* Frame, FEX::HLE::kernel_clone3_args* cl_args, size_t size) -> uint64_t {
                          FEX::HLE::clone3_args args {};
                          args.Type = TypeOfClone::TYPE_CLONE3;
                          memcpy(&args.args, cl_args, std::min(sizeof(FEX::HLE::kernel_clone3_args), size));
                          return CloneHandler(Frame, &args);
                        }));

  REGISTER_SYSCALL_IMPL(exit, [](FEXCore::Core::CpuStateFrame* Frame, int status) -> uint64_t {
    // TLS/DTV teardown is something FEX can't control. Disable glibc checking when we leave a pthread.
    // Since this thread is hard stopping, we can't track the TLS/DTV teardown in FEX's thread handling.
    FEXCore::Allocator::YesIKnowImNotSupposedToUseTheGlibcAllocator::HardDisable();
    auto ThreadObject = FEX::HLE::ThreadManager::GetStateObjectFromCPUState(Frame);

    if (ThreadObject->ThreadInfo.clear_child_tid) {
      auto Addr = std::atomic_ref<int32_t>(*ThreadObject->ThreadInfo.clear_child_tid);
      Addr.store(0);
      syscall(SYSCALL_DEF(futex), ThreadObject->ThreadInfo.clear_child_tid, FUTEX_WAKE, ~0ULL, 0, 0, 0);
    }

    ThreadObject->StatusCode = status;

    FEX::HLE::_SyscallHandler->UninstallTLSState(ThreadObject);

    if (ThreadObject->ExecutionThread) {
      // If this is a pthread based execution thread, then there is more work to be done.
      // Delegate final deletion and cleanup to the pthreads Thread management.
      FEX::LinuxEmulation::Threads::LongjumpDeallocateAndExit(ThreadObject, status);
    } else {
      FEX::HLE::_SyscallHandler->TM.DestroyThread(ThreadObject, true);
      FEX::LinuxEmulation::Threads::DeallocateStackObjectAndExit(nullptr, status);
    }
    // This will never be reached
    std::terminate();
  });

  REGISTER_SYSCALL_IMPL(prctl,
                        [](FEXCore::Core::CpuStateFrame* Frame, int option, unsigned long arg2, unsigned long arg3, unsigned long arg4,
                           unsigned long arg5) -> uint64_t {
                          uint64_t Result {};
#ifndef PR_GET_AUXV
#define PR_GET_AUXV 0x41555856
#endif
                          switch (option) {
                          case PR_SET_SECCOMP: {
                            uint32_t Operation {};
                            if (arg2 == SECCOMP_MODE_STRICT) Operation = SECCOMP_SET_MODE_STRICT;
                            if (arg2 == SECCOMP_MODE_FILTER) Operation = SECCOMP_SET_MODE_FILTER;

                            return FEX::HLE::_SyscallHandler->SeccompEmulator.Handle(Frame, Operation, 0, reinterpret_cast<void*>(arg3));
                          }
                          case PR_GET_SECCOMP: return FEX::HLE::_SyscallHandler->SeccompEmulator.GetSeccomp(Frame);
                          case PR_GET_AUXV: {
                            if (arg4 || arg5) {
                              return -EINVAL;
                            }

                            void* addr = reinterpret_cast<void*>(arg2);
                            size_t UserSize = reinterpret_cast<size_t>(arg3);

                            const auto auxv = FEX::HLE::_SyscallHandler->GetCodeLoader()->GetAuxv();
                            const auto auxvBase = auxv.address;
                            const auto auxvSize = auxv.size;
                            size_t MinSize = std::min(auxvSize, UserSize);

                            memcpy(addr, reinterpret_cast<void*>(auxvBase), MinSize);

                            // Returns the size of auxv without truncation.
                            return auxvSize;
                          }
                          default: Result = ::prctl(option, arg2, arg3, arg4, arg5); break;
                          }
                          SYSCALL_ERRNO();
                        });

  REGISTER_SYSCALL_IMPL(arch_prctl, [](FEXCore::Core::CpuStateFrame* Frame, int code, unsigned long addr) -> uint64_t {
    uint64_t Result {};
    switch (code) {
    case 0x1001: // ARCH_SET_GS
      if (addr >= SyscallHandler::TASK_MAX_64BIT) {
        // Ignore a non-canonical address
        return -EPERM;
      }
      Frame->State.gs_cached = addr;
      Result = 0;
      break;
    case 0x1002: // ARCH_SET_FS
      if (addr >= SyscallHandler::TASK_MAX_64BIT) {
        // Ignore a non-canonical address
        return -EPERM;
      }
      Frame->State.fs_cached = addr;
      Result = 0;
      break;
    case 0x1003: // ARCH_GET_FS
      *reinterpret_cast<uint64_t*>(addr) = Frame->State.fs_cached;
      Result = 0;
      break;
    case 0x1004: // ARCH_GET_GS
      *reinterpret_cast<uint64_t*>(addr) = Frame->State.gs_cached;
      Result = 0;
      break;
    case 0x3001:        // ARCH_CET_STATUS
      Result = -EINVAL; // We don't support CET, return EINVAL
      break;
    case 0x1011: // ARCH_GET_CPUID
      return 1;
      break;
    case 0x1012:      // ARCH_SET_CPUID
      return -ENODEV; // Claim we don't support faulting on CPUID
      break;
    default:
      LogMan::Msg::EFmt("Unknown prctl: 0x{:x}", code);
      Result = -EINVAL;
      break;
    }
    SYSCALL_ERRNO();
  });

  REGISTER_SYSCALL_IMPL(set_tid_address, [](FEXCore::Core::CpuStateFrame* Frame, int* tidptr) -> uint64_t {
    auto ThreadObject = FEX::HLE::ThreadManager::GetStateObjectFromCPUState(Frame);
    ThreadObject->ThreadInfo.clear_child_tid = tidptr;
    return ThreadObject->ThreadInfo.TID;
  });

  REGISTER_SYSCALL_IMPL(exit_group, [](FEXCore::Core::CpuStateFrame* Frame, int status) -> uint64_t {
    // Save telemetry if we're exiting.
    FEX::HLE::_SyscallHandler->GetSignalDelegator()->SaveTelemetry();
    FEX::HLE::_SyscallHandler->TM.CleanupForExit();

    syscall(SYSCALL_DEF(exit_group), status);
    // This will never be reached
    std::terminate();
  });
}
} // namespace FEX::HLE