1 files changed, 241 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/hwasan/hwasan_fuchsia.cpp b/contrib/llvm-project/compiler-rt/lib/hwasan/hwasan_fuchsia.cpp
new file mode 100644
index 000000000000..d1696f8aa796
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/hwasan/hwasan_fuchsia.cpp
@@ -0,0 +1,241 @@
+//===-- hwasan_fuchsia.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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file is a part of HWAddressSanitizer and contains Fuchsia-specific
+/// code.
+///
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_fuchsia.h"
+#if SANITIZER_FUCHSIA
+
+#include <zircon/features.h>
+#include <zircon/syscalls.h>
+
+#include "hwasan.h"
+#include "hwasan_interface_internal.h"
+#include "hwasan_report.h"
+#include "hwasan_thread.h"
+#include "hwasan_thread_list.h"
+
+// This TLS variable contains the location of the stack ring buffer and can be
+// used to always find the hwasan thread object associated with the current
+// running thread.
+[[gnu::tls_model("initial-exec")]]
+SANITIZER_INTERFACE_ATTRIBUTE
+THREADLOCAL uptr __hwasan_tls;
+
+namespace __hwasan {
+
+bool InitShadow() {
+  __sanitizer::InitShadowBounds();
+  CHECK_NE(__sanitizer::ShadowBounds.shadow_limit, 0);
+
+  // These variables are used by MemIsShadow for asserting we have a correct
+  // shadow address. On Fuchsia, we only have one region of shadow, so the
+  // bounds of Low shadow can be zero while High shadow represents the true
+  // bounds. Note that these are inclusive ranges.
+  kLowShadowStart = 0;
+  kLowShadowEnd = 0;
+  kHighShadowStart = __sanitizer::ShadowBounds.shadow_base;
+  kHighShadowEnd = __sanitizer::ShadowBounds.shadow_limit - 1;
+
+  return true;
+}
+
+bool MemIsApp(uptr p) {
+  CHECK(GetTagFromPointer(p) == 0);
+  return __sanitizer::ShadowBounds.shadow_limit <= p &&
+         p <= (__sanitizer::ShadowBounds.memory_limit - 1);
+}
+
+// These are known parameters passed to the hwasan runtime on thread creation.
+struct Thread::InitState {
+  uptr stack_bottom, stack_top;
+};
+
+static void FinishThreadInitialization(Thread *thread);
+
+void InitThreads() {
+  // This is the minimal alignment needed for the storage where hwasan threads
+  // and their stack ring buffers are placed. This alignment is necessary so the
+  // stack ring buffer can perform a simple calculation to get the next element
+  // in the RB. The instructions for this calculation are emitted by the
+  // compiler. (Full explanation in hwasan_thread_list.h.)
+  uptr alloc_size = UINT64_C(1) << kShadowBaseAlignment;
+  uptr thread_start = reinterpret_cast<uptr>(
+      MmapAlignedOrDieOnFatalError(alloc_size, alloc_size, __func__));
+
+  InitThreadList(thread_start, alloc_size);
+
+  // Create the hwasan thread object for the current (main) thread. Stack info
+  // for this thread is known from information passed via
+  // __sanitizer_startup_hook.
+  const Thread::InitState state = {
+      .stack_bottom = __sanitizer::MainThreadStackBase,
+      .stack_top =
+          __sanitizer::MainThreadStackBase + __sanitizer::MainThreadStackSize,
+  };
+  FinishThreadInitialization(hwasanThreadList().CreateCurrentThread(&state));
+}
+
+uptr *GetCurrentThreadLongPtr() { return &__hwasan_tls; }
+
+// This is called from the parent thread before the new thread is created. Here
+// we can propagate known info like the stack bounds to Thread::Init before
+// jumping into the thread. We cannot initialize the stack ring buffer yet since
+// we have not entered the new thread.
+static void *BeforeThreadCreateHook(uptr user_id, bool detached,
+                                    const char *name, uptr stack_bottom,
+                                    uptr stack_size) {
+  const Thread::InitState state = {
+      .stack_bottom = stack_bottom,
+      .stack_top = stack_bottom + stack_size,
+  };
+  return hwasanThreadList().CreateCurrentThread(&state);
+}
+
+// This sets the stack top and bottom according to the InitState passed to
+// CreateCurrentThread above.
+void Thread::InitStackAndTls(const InitState *state) {
+  CHECK_NE(state->stack_bottom, 0);
+  CHECK_NE(state->stack_top, 0);
+  stack_bottom_ = state->stack_bottom;
+  stack_top_ = state->stack_top;
+  tls_end_ = tls_begin_ = 0;
+}
+
+// This is called after creating a new thread with the pointer returned by
+// BeforeThreadCreateHook. We are still in the creating thread and should check
+// if it was actually created correctly.
+static void ThreadCreateHook(void *hook, bool aborted) {
+  Thread *thread = static_cast<Thread *>(hook);
+  if (!aborted) {
+    // The thread was created successfully.
+    // ThreadStartHook can already be running in the new thread.
+  } else {
+    // The thread wasn't created after all.
+    // Clean up everything we set up in BeforeThreadCreateHook.
+    atomic_signal_fence(memory_order_seq_cst);
+    hwasanThreadList().ReleaseThread(thread);
+  }
+}
+
+// This is called in the newly-created thread before it runs anything else,
+// with the pointer returned by BeforeThreadCreateHook (above). Here we can
+// setup the stack ring buffer.
+static void ThreadStartHook(void *hook, thrd_t self) {
+  Thread *thread = static_cast<Thread *>(hook);
+  FinishThreadInitialization(thread);
+  thread->EnsureRandomStateInited();
+}
+
+// This is the function that sets up the stack ring buffer and enables us to use
+// GetCurrentThread. This function should only be called while IN the thread
+// that we want to create the hwasan thread object for so __hwasan_tls can be
+// properly referenced.
+static void FinishThreadInitialization(Thread *thread) {
+  CHECK_NE(thread, nullptr);
+
+  // The ring buffer is located immediately before the thread object.
+  uptr stack_buffer_size = hwasanThreadList().GetRingBufferSize();
+  uptr stack_buffer_start = reinterpret_cast<uptr>(thread) - stack_buffer_size;
+  thread->InitStackRingBuffer(stack_buffer_start, stack_buffer_size);
+}
+
+static void ThreadExitHook(void *hook, thrd_t self) {
+  Thread *thread = static_cast<Thread *>(hook);
+  atomic_signal_fence(memory_order_seq_cst);
+  hwasanThreadList().ReleaseThread(thread);
+}
+
+uptr TagMemoryAligned(uptr p, uptr size, tag_t tag) {
+  CHECK(IsAligned(p, kShadowAlignment));
+  CHECK(IsAligned(size, kShadowAlignment));
+  __sanitizer_fill_shadow(p, size, tag,
+                          common_flags()->clear_shadow_mmap_threshold);
+  return AddTagToPointer(p, tag);
+}
+
+// Not implemented because Fuchsia does not use signal handlers.
+void HwasanOnDeadlySignal(int signo, void *info, void *context) {}
+
+// Not implemented because Fuchsia does not use interceptors.
+void InitializeInterceptors() {}
+
+// Not implemented because this is only relevant for Android.
+void AndroidTestTlsSlot() {}
+
+// TSD was normally used on linux as a means of calling the hwasan thread exit
+// handler passed to pthread_key_create. This is not needed on Fuchsia because
+// we will be using __sanitizer_thread_exit_hook.
+void HwasanTSDInit() {}
+void HwasanTSDThreadInit() {}
+
+// On linux, this just would call `atexit(HwasanAtExit)`. The functions in
+// HwasanAtExit are unimplemented for Fuchsia and effectively no-ops, so this
+// function is unneeded.
+void InstallAtExitHandler() {}
+
+void HwasanInstallAtForkHandler() {}
+
+void InstallAtExitCheckLeaks() {}
+
+void InitializeOsSupport() {
+#ifdef __aarch64__
+  uint32_t features = 0;
+  CHECK_EQ(zx_system_get_features(ZX_FEATURE_KIND_ADDRESS_TAGGING, &features),
+           ZX_OK);
+  if (!(features & ZX_ARM64_FEATURE_ADDRESS_TAGGING_TBI) &&
+      flags()->fail_without_syscall_abi) {
+    Printf(
+        "FATAL: HWAddressSanitizer requires "
+        "ZX_ARM64_FEATURE_ADDRESS_TAGGING_TBI.\n");
+    Die();
+  }
+#endif
+}
+
+}  // namespace __hwasan
+
+namespace __lsan {
+
+bool UseExitcodeOnLeak() { return __hwasan::flags()->halt_on_error; }
+
+}  // namespace __lsan
+
+extern "C" {
+
+void *__sanitizer_before_thread_create_hook(thrd_t thread, bool detached,
+                                            const char *name, void *stack_base,
+                                            size_t stack_size) {
+  return __hwasan::BeforeThreadCreateHook(
+      reinterpret_cast<uptr>(thread), detached, name,
+      reinterpret_cast<uptr>(stack_base), stack_size);
+}
+
+void __sanitizer_thread_create_hook(void *hook, thrd_t thread, int error) {
+  __hwasan::ThreadCreateHook(hook, error != thrd_success);
+}
+
+void __sanitizer_thread_start_hook(void *hook, thrd_t self) {
+  __hwasan::ThreadStartHook(hook, reinterpret_cast<uptr>(self));
+}
+
+void __sanitizer_thread_exit_hook(void *hook, thrd_t self) {
+  __hwasan::ThreadExitHook(hook, self);
+}
+
+void __sanitizer_module_loaded(const struct dl_phdr_info *info, size_t) {
+  __hwasan_library_loaded(info->dlpi_addr, info->dlpi_phdr, info->dlpi_phnum);
+}
+
+}  // extern "C"
+
+#endif  // SANITIZER_FUCHSIA