diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index 2c4a300..d5d87b4 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -21,6 +21,7 @@
 #include <string>
 #include <unordered_map>
 
+#include <android-base/thread_annotations.h>
 #include <android/native_window.h>
 #include <binder/IBinder.h>
 #include <gui/LayerState.h>
@@ -28,6 +29,7 @@
 #include <renderengine/RenderEngine.h>
 #include <system/window.h>
 #include <ui/DisplayId.h>
+#include <ui/DisplayIdentification.h>
 #include <ui/DisplayState.h>
 #include <ui/GraphicTypes.h>
 #include <ui/HdrCapabilities.h>
@@ -39,15 +41,11 @@
 #include <utils/RefBase.h>
 #include <utils/Timers.h>
 
-#include "MainThreadGuard.h"
-
-#include <ui/DisplayIdentification.h>
 #include "DisplayHardware/DisplayMode.h"
 #include "DisplayHardware/Hal.h"
 #include "DisplayHardware/PowerAdvisor.h"
-
 #include "Scheduler/RefreshRateConfigs.h"
-
+#include "ThreadContext.h"
 #include "TracedOrdinal.h"
 
 namespace android {
@@ -99,9 +97,9 @@
     void setLayerStack(ui::LayerStack);
     void setDisplaySize(int width, int height);
     void setProjection(ui::Rotation orientation, Rect viewport, Rect frame);
-    void stageBrightness(float brightness) REQUIRES(SF_MAIN_THREAD);
-    void persistBrightness(bool needsComposite) REQUIRES(SF_MAIN_THREAD);
-    bool isBrightnessStale() const REQUIRES(SF_MAIN_THREAD);
+    void stageBrightness(float brightness) REQUIRES(kMainThreadContext);
+    void persistBrightness(bool needsComposite) REQUIRES(kMainThreadContext);
+    bool isBrightnessStale() const REQUIRES(kMainThreadContext);
     void setFlags(uint32_t flags);
 
     ui::Rotation getPhysicalOrientation() const { return mPhysicalOrientation; }
@@ -109,7 +107,7 @@
 
     static ui::Transform::RotationFlags getPrimaryDisplayRotationFlags();
 
-    std::optional<float> getStagedBrightness() const REQUIRES(SF_MAIN_THREAD);
+    std::optional<float> getStagedBrightness() const REQUIRES(kMainThreadContext);
     ui::Transform::RotationFlags getTransformHint() const;
     const ui::Transform& getTransform() const;
     const Rect& getLayerStackSpaceRect() const;
@@ -209,15 +207,15 @@
     bool setDesiredActiveMode(const ActiveModeInfo&) EXCLUDES(mActiveModeLock);
     std::optional<ActiveModeInfo> getDesiredActiveMode() const EXCLUDES(mActiveModeLock);
     void clearDesiredActiveModeState() EXCLUDES(mActiveModeLock);
-    ActiveModeInfo getUpcomingActiveMode() const REQUIRES(SF_MAIN_THREAD) {
+    ActiveModeInfo getUpcomingActiveMode() const REQUIRES(kMainThreadContext) {
         return mUpcomingActiveMode;
     }
 
-    void setActiveMode(DisplayModeId) REQUIRES(SF_MAIN_THREAD);
+    void setActiveMode(DisplayModeId) REQUIRES(kMainThreadContext);
     status_t initiateModeChange(const ActiveModeInfo&,
                                 const hal::VsyncPeriodChangeConstraints& constraints,
                                 hal::VsyncPeriodChangeTimeline* outTimeline)
-            REQUIRES(SF_MAIN_THREAD);
+            REQUIRES(kMainThreadContext);
 
     // Return the immutable list of supported display modes. The HWC may report different modes
     // after a hotplug reconnect event, in which case the DisplayDevice object will be recreated.
@@ -304,7 +302,7 @@
     ActiveModeInfo mDesiredActiveMode GUARDED_BY(mActiveModeLock);
     TracedOrdinal<bool> mDesiredActiveModeChanged
             GUARDED_BY(mActiveModeLock) = {"DesiredActiveModeChanged", false};
-    ActiveModeInfo mUpcomingActiveMode GUARDED_BY(SF_MAIN_THREAD);
+    ActiveModeInfo mUpcomingActiveMode GUARDED_BY(kMainThreadContext);
 };
 
 struct DisplayDeviceState {
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index fa5a1c8..894fb8d 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -37,6 +37,7 @@
 #include <cutils/native_handle.h>
 #include <cutils/properties.h>
 #include <ftl/enum.h>
+#include <ftl/fake_guard.h>
 #include <gui/BufferItem.h>
 #include <gui/LayerDebugInfo.h>
 #include <gui/Surface.h>
@@ -2045,10 +2046,10 @@
     writeToProtoCommonState(layerProto, LayerVector::StateSet::Drawing, traceFlags);
 
     if (traceFlags & LayerTracing::TRACE_COMPOSITION) {
+        ftl::FakeGuard guard(mFlinger->mStateLock); // Called from the main thread.
+
         // Only populate for the primary display.
-        UnnecessaryLock assumeLocked(mFlinger->mStateLock); // called from the main thread.
-        const auto display = mFlinger->getDefaultDisplayDeviceLocked();
-        if (display) {
+        if (const auto display = mFlinger->getDefaultDisplayDeviceLocked()) {
             const auto compositionType = getCompositionType(*display);
             layerProto->set_hwc_composition_type(static_cast<HwcCompositionType>(compositionType));
             LayerProtoHelper::writeToProto(getVisibleRegion(display.get()),
diff --git a/services/surfaceflinger/MainThreadGuard.h b/services/surfaceflinger/MainThreadGuard.h
deleted file mode 100644
index c1aa118..0000000
--- a/services/surfaceflinger/MainThreadGuard.h
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * Copyright 2021 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-
-#include <utils/Mutex.h>
-
-namespace android {
-namespace {
-
-// Helps to ensure that some functions runs on SF's main thread by using the
-// clang thread safety annotations.
-class CAPABILITY("mutex") MainThreadGuard {
-} SF_MAIN_THREAD;
-
-struct SCOPED_CAPABILITY MainThreadScopedGuard {
-public:
-    explicit MainThreadScopedGuard(MainThreadGuard& mutex) ACQUIRE(mutex) {}
-    ~MainThreadScopedGuard() RELEASE() {}
-};
-} // namespace
-} // namespace android
diff --git a/services/surfaceflinger/MutexUtils.h b/services/surfaceflinger/MutexUtils.h
new file mode 100644
index 0000000..f8be6f3
--- /dev/null
+++ b/services/surfaceflinger/MutexUtils.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <log/log.h>
+#include <utils/Mutex.h>
+
+namespace android {
+
+struct SCOPED_CAPABILITY ConditionalLock {
+    ConditionalLock(Mutex& mutex, bool lock) ACQUIRE(mutex) : mutex(mutex), lock(lock) {
+        if (lock) mutex.lock();
+    }
+
+    ~ConditionalLock() RELEASE() {
+        if (lock) mutex.unlock();
+    }
+
+    Mutex& mutex;
+    const bool lock;
+};
+
+struct SCOPED_CAPABILITY TimedLock {
+    TimedLock(Mutex& mutex, nsecs_t timeout, const char* whence) ACQUIRE(mutex)
+          : mutex(mutex), status(mutex.timedLock(timeout)) {
+        ALOGE_IF(!locked(), "%s timed out locking: %s (%d)", whence, strerror(-status), status);
+    }
+
+    ~TimedLock() RELEASE() {
+        if (locked()) mutex.unlock();
+    }
+
+    bool locked() const { return status == NO_ERROR; }
+
+    Mutex& mutex;
+    const status_t status;
+};
+
+} // namespace android
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 9f5a7df..4fc9d27 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -24,7 +24,10 @@
 
 #include "SurfaceFlinger.h"
 
+#include <android-base/parseint.h>
 #include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
 #include <android/configuration.h>
 #include <android/gui/IDisplayEventConnection.h>
 #include <android/hardware/configstore/1.0/ISurfaceFlingerConfigs.h>
@@ -49,6 +52,7 @@
 #include <configstore/Utils.h>
 #include <cutils/compiler.h>
 #include <cutils/properties.h>
+#include <ftl/fake_guard.h>
 #include <ftl/future.h>
 #include <ftl/small_map.h>
 #include <gui/BufferQueue.h>
@@ -123,6 +127,7 @@
 #include "LayerRenderArea.h"
 #include "LayerVector.h"
 #include "MonitoredProducer.h"
+#include "MutexUtils.h"
 #include "NativeWindowSurface.h"
 #include "RefreshRateOverlay.h"
 #include "RegionSamplingThread.h"
@@ -138,49 +143,26 @@
 #include "TimeStats/TimeStats.h"
 #include "TunnelModeEnabledReporter.h"
 #include "WindowInfosListenerInvoker.h"
-#include "android-base/parseint.h"
-#include "android-base/stringprintf.h"
-#include "android-base/strings.h"
 
 #include <aidl/android/hardware/graphics/common/DisplayDecorationSupport.h>
 #include <aidl/android/hardware/graphics/composer3/DisplayCapability.h>
 
-#define MAIN_THREAD ACQUIRE(mStateLock) RELEASE(mStateLock)
-
-// Note: The parentheses around `expr` are needed to deduce an lvalue or rvalue reference.
-#define ON_MAIN_THREAD(expr)                                       \
-    [&]() -> decltype(auto) {                                      \
-        LOG_FATAL_IF(std::this_thread::get_id() != mMainThreadId); \
-        UnnecessaryLock lock(mStateLock);                          \
-        return (expr);                                             \
-    }()
-
-#define MAIN_THREAD_GUARD(expr)                                    \
-    [&]() -> decltype(auto) {                                      \
-        LOG_FATAL_IF(std::this_thread::get_id() != mMainThreadId); \
-        MainThreadScopedGuard lock(SF_MAIN_THREAD);                \
-        return (expr);                                             \
-    }()
-
 #undef NO_THREAD_SAFETY_ANALYSIS
 #define NO_THREAD_SAFETY_ANALYSIS \
-    _Pragma("GCC error \"Prefer MAIN_THREAD macros or {Conditional,Timed,Unnecessary}Lock.\"")
-
-using aidl::android::hardware::graphics::common::DisplayDecorationSupport;
-using aidl::android::hardware::graphics::composer3::Capability;
-using aidl::android::hardware::graphics::composer3::DisplayCapability;
-using KernelIdleTimerController =
-        ::android::scheduler::RefreshRateConfigs::KernelIdleTimerController;
+    _Pragma("GCC error \"Prefer <ftl/fake_guard.h> or MutexUtils.h helpers.\"")
 
 namespace android {
 
 using namespace std::string_literals;
 
-using namespace android::hardware::configstore;
-using namespace android::hardware::configstore::V1_0;
-using namespace android::sysprop;
+using namespace hardware::configstore;
+using namespace hardware::configstore::V1_0;
+using namespace sysprop;
 
-using android::hardware::power::Boost;
+using aidl::android::hardware::graphics::common::DisplayDecorationSupport;
+using aidl::android::hardware::graphics::composer3::Capability;
+using aidl::android::hardware::graphics::composer3::DisplayCapability;
+
 using base::StringAppendF;
 using gui::DisplayInfo;
 using gui::IDisplayEventConnection;
@@ -191,6 +173,8 @@
 using ui::DisplayPrimaries;
 using ui::RenderIntent;
 
+using KernelIdleTimerController = scheduler::RefreshRateConfigs::KernelIdleTimerController;
+
 namespace hal = android::hardware::graphics::composer::hal;
 
 namespace {
@@ -222,38 +206,6 @@
 
 #pragma clang diagnostic pop
 
-template <typename Mutex>
-struct SCOPED_CAPABILITY ConditionalLockGuard {
-    ConditionalLockGuard(Mutex& mutex, bool lock) ACQUIRE(mutex) : mutex(mutex), lock(lock) {
-        if (lock) mutex.lock();
-    }
-
-    ~ConditionalLockGuard() RELEASE() {
-        if (lock) mutex.unlock();
-    }
-
-    Mutex& mutex;
-    const bool lock;
-};
-
-using ConditionalLock = ConditionalLockGuard<Mutex>;
-
-struct SCOPED_CAPABILITY TimedLock {
-    TimedLock(Mutex& mutex, nsecs_t timeout, const char* whence) ACQUIRE(mutex)
-          : mutex(mutex), status(mutex.timedLock(timeout)) {
-        ALOGE_IF(!locked(), "%s timed out locking: %s (%d)", whence, strerror(-status), status);
-    }
-
-    ~TimedLock() RELEASE() {
-        if (locked()) mutex.unlock();
-    }
-
-    bool locked() const { return status == NO_ERROR; }
-
-    Mutex& mutex;
-    const status_t status;
-};
-
 // TODO(b/141333600): Consolidate with DisplayMode::Builder::getDefaultDensity.
 constexpr float FALLBACK_DENSITY = ACONFIGURATION_DENSITY_TV;
 
@@ -735,7 +687,7 @@
         mBootStage = BootStage::FINISHED;
 
         if (property_get_bool("sf.debug.show_refresh_rate_overlay", false)) {
-            ON_MAIN_THREAD(enableRefreshRateOverlay(true));
+            FTL_FAKE_GUARD(mStateLock, enableRefreshRateOverlay(true));
         }
     }));
 }
@@ -936,8 +888,9 @@
         FrameEvent::DEQUEUE_READY,
         FrameEvent::RELEASE,
     };
-    ConditionalLock _l(mStateLock,
-            std::this_thread::get_id() != mMainThreadId);
+
+    ConditionalLock lock(mStateLock, std::this_thread::get_id() != mMainThreadId);
+
     if (!getHwComposer().hasCapability(Capability::PRESENT_FENCE_IS_NOT_RELIABLE)) {
         outSupported->push_back(FrameEvent::DISPLAY_PRESENT);
     }
@@ -1142,7 +1095,7 @@
     }
 
     auto future = mScheduler->schedule([=]() -> status_t {
-        const auto display = ON_MAIN_THREAD(getDisplayDeviceLocked(displayToken));
+        const auto display = FTL_FAKE_GUARD(mStateLock, getDisplayDeviceLocked(displayToken));
         if (!display) {
             ALOGE("Attempt to set allowed display modes for invalid display token %p",
                   displayToken.get());
@@ -1183,7 +1136,9 @@
         return;
     }
 
-    const auto upcomingModeInfo = MAIN_THREAD_GUARD(display->getUpcomingActiveMode());
+    const auto upcomingModeInfo =
+            FTL_FAKE_GUARD(kMainThreadContext, display->getUpcomingActiveMode());
+
     if (!upcomingModeInfo.mode) {
         // There is no pending mode change. This can happen if the active
         // display changed and the mode change happened on a different display.
@@ -1202,9 +1157,8 @@
         return;
     }
 
-    // We just created this display so we can call even if we are not on
-    // the main thread
-    MainThreadScopedGuard fakeMainThreadGuard(SF_MAIN_THREAD);
+    // We just created this display so we can call even if we are not on the main thread.
+    ftl::FakeGuard guard(kMainThreadContext);
     display->setActiveMode(upcomingModeInfo.mode->getId());
 
     const Fps refreshRate = upcomingModeInfo.mode->getFps();
@@ -1289,8 +1243,10 @@
         constraints.seamlessRequired = false;
         hal::VsyncPeriodChangeTimeline outTimeline;
 
-        const auto status = MAIN_THREAD_GUARD(
-                display->initiateModeChange(*desiredActiveMode, constraints, &outTimeline));
+        const auto status = FTL_FAKE_GUARD(kMainThreadContext,
+                                           display->initiateModeChange(*desiredActiveMode,
+                                                                       constraints, &outTimeline));
+
         if (status != NO_ERROR) {
             // initiateModeChange may fail if a hotplug event is just about
             // to be sent. We just log the error in this case.
@@ -1323,7 +1279,7 @@
 }
 
 void SurfaceFlinger::disableExpensiveRendering() {
-    auto future = mScheduler->schedule([=]() MAIN_THREAD {
+    auto future = mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) {
         ATRACE_CALL();
         if (mPowerAdvisor.isUsingExpensiveRendering()) {
             for (const auto& [_, display] : mDisplays) {
@@ -1372,7 +1328,7 @@
         return BAD_VALUE;
     }
 
-    auto future = mScheduler->schedule([=]() MAIN_THREAD -> status_t {
+    auto future = mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) -> status_t {
         const auto display = getDisplayDeviceLocked(displayToken);
         if (!display) {
             ALOGE("Attempt to set active color mode %s (%d) for invalid display token %p",
@@ -1407,17 +1363,17 @@
 }
 
 status_t SurfaceFlinger::getBootDisplayModeSupport(bool* outSupport) const {
-    auto future = mScheduler->schedule([=]() MAIN_THREAD mutable -> status_t {
-        *outSupport = getHwComposer().hasCapability(Capability::BOOT_DISPLAY_CONFIG);
-        return NO_ERROR;
-    });
-    return future.get();
+    auto future = mScheduler->schedule(
+            [this] { return getHwComposer().hasCapability(Capability::BOOT_DISPLAY_CONFIG); });
+
+    *outSupport = future.get();
+    return NO_ERROR;
 }
 
 status_t SurfaceFlinger::setBootDisplayMode(const sp<IBinder>& displayToken,
                                             ui::DisplayModeId modeId) {
     const char* const whence = __func__;
-    auto future = mScheduler->schedule([=]() MAIN_THREAD -> status_t {
+    auto future = mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) -> status_t {
         const auto display = getDisplayDeviceLocked(displayToken);
         if (!display) {
             ALOGE("%s: Invalid display token %p", whence, displayToken.get());
@@ -1444,7 +1400,7 @@
 
 status_t SurfaceFlinger::clearBootDisplayMode(const sp<IBinder>& displayToken) {
     const char* const whence = __func__;
-    auto future = mScheduler->schedule([=]() MAIN_THREAD -> status_t {
+    auto future = mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) -> status_t {
         if (const auto displayId = getPhysicalDisplayIdLocked(displayToken)) {
             return getHwComposer().clearBootDisplayMode(*displayId);
         } else {
@@ -1457,7 +1413,7 @@
 
 void SurfaceFlinger::setAutoLowLatencyMode(const sp<IBinder>& displayToken, bool on) {
     const char* const whence = __func__;
-    static_cast<void>(mScheduler->schedule([=]() MAIN_THREAD {
+    static_cast<void>(mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) {
         if (const auto displayId = getPhysicalDisplayIdLocked(displayToken)) {
             getHwComposer().setAutoLowLatencyMode(*displayId, on);
         } else {
@@ -1468,7 +1424,7 @@
 
 void SurfaceFlinger::setGameContentType(const sp<IBinder>& displayToken, bool on) {
     const char* const whence = __func__;
-    static_cast<void>(mScheduler->schedule([=]() MAIN_THREAD {
+    static_cast<void>(mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) {
         if (const auto displayId = getPhysicalDisplayIdLocked(displayToken)) {
             const auto type = on ? hal::ContentType::GAME : hal::ContentType::NONE;
             getHwComposer().setContentType(*displayId, type);
@@ -1533,7 +1489,7 @@
                                                           bool enable, uint8_t componentMask,
                                                           uint64_t maxFrames) {
     const char* const whence = __func__;
-    auto future = mScheduler->schedule([=]() MAIN_THREAD -> status_t {
+    auto future = mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) -> status_t {
         if (const auto displayId = getPhysicalDisplayIdLocked(displayToken)) {
             return getHwComposer().setDisplayContentSamplingEnabled(*displayId, enable,
                                                                     componentMask, maxFrames);
@@ -1610,7 +1566,7 @@
 status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) {
     outLayers->clear();
     auto future = mScheduler->schedule([=] {
-        const auto display = ON_MAIN_THREAD(getDefaultDisplayDeviceLocked());
+        const auto display = FTL_FAKE_GUARD(mStateLock, getDefaultDisplayDeviceLocked());
         mDrawingState.traverseInZOrder([&](Layer* layer) {
             outLayers->push_back(layer->getLayerDebugInfo(display.get()));
         });
@@ -1722,7 +1678,7 @@
     }
 
     const char* const whence = __func__;
-    return ftl::chain(mScheduler->schedule([=]() MAIN_THREAD {
+    return ftl::chain(mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) {
                if (const auto display = getDisplayDeviceLocked(displayToken)) {
                    const bool supportsDisplayBrightnessCommand =
                            getHwComposer().getComposer()->isSupported(
@@ -1736,7 +1692,9 @@
                                compositionDisplay->editState().displayBrightnessNits;
                        compositionDisplay->setDisplayBrightness(brightness.sdrWhitePointNits,
                                                                 brightness.displayBrightnessNits);
-                       MAIN_THREAD_GUARD(display->stageBrightness(brightness.displayBrightness));
+                       FTL_FAKE_GUARD(kMainThreadContext,
+                                      display->stageBrightness(brightness.displayBrightness));
+
                        if (brightness.sdrWhitePointNits / brightness.displayBrightnessNits !=
                            currentDimmingRatio) {
                            scheduleComposite(FrameHint::kNone);
@@ -1806,6 +1764,7 @@
 }
 
 status_t SurfaceFlinger::notifyPowerBoost(int32_t boostId) {
+    using hardware::power::Boost;
     Boost powerBoost = static_cast<Boost>(boostId);
 
     if (powerBoost == Boost::INTERACTION) {
@@ -1966,7 +1925,7 @@
     ATRACE_CALL();
 
     // On main thread to avoid race conditions with display power state.
-    static_cast<void>(mScheduler->schedule([=]() MAIN_THREAD {
+    static_cast<void>(mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) {
         mHWCVsyncPendingState = enabled ? hal::Vsync::ENABLE : hal::Vsync::DISABLE;
 
         if (const auto display = getDefaultDisplayDeviceLocked();
@@ -2014,8 +1973,8 @@
                                                           : stats.vsyncTime + stats.vsyncPeriod;
 }
 
-bool SurfaceFlinger::commit(nsecs_t frameTime, int64_t vsyncId, nsecs_t expectedVsyncTime) {
-    MainThreadScopedGuard mainThreadGuard(SF_MAIN_THREAD);
+bool SurfaceFlinger::commit(nsecs_t frameTime, int64_t vsyncId, nsecs_t expectedVsyncTime)
+        FTL_FAKE_GUARD(kMainThreadContext) {
     // we set this once at the beginning of commit to ensure consistency throughout the whole frame
     mPowerHintSessionData.sessionEnabled = mPowerAdvisor.usePowerHintSession();
     if (mPowerHintSessionData.sessionEnabled) {
@@ -2181,20 +2140,21 @@
         mLayerTracing.notify(mVisibleRegionsDirty, frameTime);
     }
 
-    MAIN_THREAD_GUARD(persistDisplayBrightness(mustComposite));
+    persistDisplayBrightness(mustComposite);
 
     return mustComposite && CC_LIKELY(mBootStage != BootStage::BOOTLOADER);
 }
 
-void SurfaceFlinger::composite(nsecs_t frameTime, int64_t vsyncId) {
+void SurfaceFlinger::composite(nsecs_t frameTime, int64_t vsyncId)
+        FTL_FAKE_GUARD(kMainThreadContext) {
     ATRACE_FORMAT("%s %" PRId64, __func__, vsyncId);
-    MainThreadScopedGuard mainThreadGuard(SF_MAIN_THREAD);
+
     if (mPowerHintSessionData.sessionEnabled) {
         mPowerHintSessionData.compositeStart = systemTime();
     }
 
     compositionengine::CompositionRefreshArgs refreshArgs;
-    const auto& displays = ON_MAIN_THREAD(mDisplays);
+    const auto& displays = FTL_FAKE_GUARD(mStateLock, mDisplays);
     refreshArgs.outputs.reserve(displays.size());
     for (const auto& [_, display] : displays) {
         refreshArgs.outputs.push_back(display->getCompositionDisplay());
@@ -2432,7 +2392,7 @@
     ATRACE_CALL();
     ALOGV("postComposition");
 
-    const auto* display = ON_MAIN_THREAD(getDefaultDisplayDeviceLocked()).get();
+    const auto* display = FTL_FAKE_GUARD(mStateLock, getDefaultDisplayDeviceLocked()).get();
 
     getBE().mGlCompositionDoneTimeline.updateSignalTimes();
     std::shared_ptr<FenceTime> glCompositionDoneFenceTime;
@@ -2632,44 +2592,37 @@
 }
 
 FloatRect SurfaceFlinger::getMaxDisplayBounds() {
-    // Find the largest width and height among all the displays.
-    int32_t maxDisplayWidth = 0;
-    int32_t maxDisplayHeight = 0;
+    const ui::Size maxSize = [this] {
+        ftl::FakeGuard guard(mStateLock);
 
-    // If there are no displays, set a valid display bounds so we can still compute a valid layer
-    // bounds.
-    if (ON_MAIN_THREAD(mDisplays.size()) == 0) {
-        maxDisplayWidth = maxDisplayHeight = 5000;
-    }
+        // The LayerTraceGenerator tool runs without displays.
+        if (mDisplays.empty()) return ui::Size{5000, 5000};
 
-    for (const auto& pair : ON_MAIN_THREAD(mDisplays)) {
-        const auto& displayDevice = pair.second;
-        int32_t width = displayDevice->getWidth();
-        int32_t height = displayDevice->getHeight();
-        if (width > maxDisplayWidth) {
-            maxDisplayWidth = width;
-        }
-        if (height > maxDisplayHeight) {
-            maxDisplayHeight = height;
-        }
-    }
+        return std::accumulate(mDisplays.begin(), mDisplays.end(), ui::kEmptySize,
+                               [](ui::Size size, const auto& pair) -> ui::Size {
+                                   const auto& display = pair.second;
+                                   return {std::max(size.getWidth(), display->getWidth()),
+                                           std::max(size.getHeight(), display->getHeight())};
+                               });
+    }();
 
     // Ignore display bounds for now since they will be computed later. Use a large Rect bound
     // to ensure it's bigger than an actual display will be.
-    FloatRect maxBounds = FloatRect(-maxDisplayWidth * 10, -maxDisplayHeight * 10,
-                                    maxDisplayWidth * 10, maxDisplayHeight * 10);
-    return maxBounds;
+    const float xMax = maxSize.getWidth() * 10.f;
+    const float yMax = maxSize.getHeight() * 10.f;
+
+    return {-xMax, -yMax, xMax, yMax};
 }
 
 void SurfaceFlinger::computeLayerBounds() {
-    FloatRect maxBounds = getMaxDisplayBounds();
+    const FloatRect maxBounds = getMaxDisplayBounds();
     for (const auto& layer : mDrawingState.layersSortedByZ) {
         layer->computeBounds(maxBounds, ui::Transform(), 0.f /* shadowRadius */);
     }
 }
 
 void SurfaceFlinger::postFrame() {
-    const auto display = ON_MAIN_THREAD(getDefaultDisplayDeviceLocked());
+    const auto display = FTL_FAKE_GUARD(mStateLock, getDefaultDisplayDeviceLocked());
     if (display && getHwComposer().isConnected(display->getPhysicalId())) {
         uint32_t flipCount = display->getPageFlipCount();
         if (flipCount % LOG_FRAME_STATS_PERIOD == 0) {
@@ -2923,7 +2876,8 @@
                                                     RenderIntent::COLORIMETRIC,
                                                     Dataspace::UNKNOWN});
     if (!state.isVirtual()) {
-        MAIN_THREAD_GUARD(display->setActiveMode(state.physical->activeMode->getId()));
+        FTL_FAKE_GUARD(kMainThreadContext,
+                       display->setActiveMode(state.physical->activeMode->getId()));
         display->setDeviceProductInfo(state.physical->deviceProductInfo);
     }
 
@@ -3293,7 +3247,7 @@
         return;
     }
 
-    for (const auto& [_, display] : ON_MAIN_THREAD(mDisplays)) {
+    for (const auto& [_, display] : FTL_FAKE_GUARD(mStateLock, mDisplays)) {
         if (const auto brightness = display->getStagedBrightness(); brightness) {
             if (!needsComposite) {
                 const status_t error =
@@ -3316,7 +3270,7 @@
                                       std::vector<DisplayInfo>& outDisplayInfos) {
     ftl::SmallMap<ui::LayerStack, DisplayDevice::InputInfo, 4> displayInputInfos;
 
-    for (const auto& [_, display] : ON_MAIN_THREAD(mDisplays)) {
+    for (const auto& [_, display] : FTL_FAKE_GUARD(mStateLock, mDisplays)) {
         const auto layerStack = display->getLayerStack();
         const auto info = display->getInputInfo();
 
@@ -3361,7 +3315,7 @@
 
 void SurfaceFlinger::updateCursorAsync() {
     compositionengine::CompositionRefreshArgs refreshArgs;
-    for (const auto& [_, display] : ON_MAIN_THREAD(mDisplays)) {
+    for (const auto& [_, display] : FTL_FAKE_GUARD(mStateLock, mDisplays)) {
         if (HalDisplayId::tryCast(display->getId())) {
             refreshArgs.outputs.push_back(display->getCompositionDisplay());
         }
@@ -3546,7 +3500,7 @@
 }
 
 void SurfaceFlinger::invalidateLayerStack(const sp<const Layer>& layer, const Region& dirty) {
-    for (const auto& [token, displayDevice] : ON_MAIN_THREAD(mDisplays)) {
+    for (const auto& [token, displayDevice] : FTL_FAKE_GUARD(mStateLock, mDisplays)) {
         auto display = displayDevice->getCompositionDisplay();
         if (display->includesLayer(layer->getOutputFilter())) {
             display->editState().dirtyRegion.orSelf(dirty);
@@ -4832,7 +4786,8 @@
 
 void SurfaceFlinger::initializeDisplays() {
     // Async since we may be called from the main thread.
-    static_cast<void>(mScheduler->schedule([this]() MAIN_THREAD { onInitializeDisplays(); }));
+    static_cast<void>(
+            mScheduler->schedule([this]() FTL_FAKE_GUARD(mStateLock) { onInitializeDisplays(); }));
 }
 
 void SurfaceFlinger::setPowerModeInternal(const sp<DisplayDevice>& display, hal::PowerMode mode) {
@@ -4932,7 +4887,7 @@
 }
 
 void SurfaceFlinger::setPowerMode(const sp<IBinder>& displayToken, int mode) {
-    auto future = mScheduler->schedule([=]() MAIN_THREAD {
+    auto future = mScheduler->schedule([=]() FTL_FAKE_GUARD(mStateLock) {
         const auto display = getDisplayDeviceLocked(displayToken);
         if (!display) {
             ALOGE("Attempt to set power mode %d for invalid display token %p", mode,
@@ -4979,7 +4934,7 @@
 
         bool dumpLayers = true;
         {
-            TimedLock lock(mStateLock, s2ns(1), __FUNCTION__);
+            TimedLock lock(mStateLock, s2ns(1), __func__);
             if (!lock.locked()) {
                 StringAppendF(&result, "Dumping without lock after timeout: %s (%d)\n",
                               strerror(-lock.status), lock.status);
@@ -5067,8 +5022,6 @@
     mFrameTimeline->parseArgs(args, result);
 }
 
-// This should only be called from the main thread.  Otherwise it would need
-// the lock and should use mCurrentState rather than mDrawingState.
 void SurfaceFlinger::logFrameStats() {
     mDrawingState.traverse([&](Layer* layer) {
         layer->logFrameStats();
@@ -5226,7 +5179,7 @@
 }
 
 void SurfaceFlinger::dumpDisplayProto(LayersTraceProto& layersTraceProto) const {
-    for (const auto& [_, display] : ON_MAIN_THREAD(mDisplays)) {
+    for (const auto& [_, display] : FTL_FAKE_GUARD(mStateLock, mDisplays)) {
         DisplayProto* displayProto = layersTraceProto.add_displays();
         displayProto->set_id(display->getId().value);
         displayProto->set_name(display->getDisplayName());
@@ -5867,7 +5820,7 @@
                         int64_t startingTime =
                                 (fixedStartingTime) ? fixedStartingTime : systemTime();
                         mScheduler
-                                ->schedule([&]() MAIN_THREAD {
+                                ->schedule([&]() FTL_FAKE_GUARD(mStateLock) {
                                     mLayerTracing.notify("start", startingTime);
                                 })
                                 .wait();
@@ -5980,10 +5933,12 @@
                     switch (n = data.readInt32()) {
                         case 0:
                         case 1:
-                            ON_MAIN_THREAD(enableRefreshRateOverlay(static_cast<bool>(n)));
+                            FTL_FAKE_GUARD(mStateLock,
+                                           enableRefreshRateOverlay(static_cast<bool>(n)));
                             break;
                         default: {
-                            reply->writeBool(ON_MAIN_THREAD(isRefreshRateOverlayEnabled()));
+                            reply->writeBool(
+                                    FTL_FAKE_GUARD(mStateLock, isRefreshRateOverlayEnabled()));
                         }
                     }
                 });
@@ -6021,7 +5976,7 @@
                     return mScheduler
                             ->schedule([this] {
                                 const auto display =
-                                        ON_MAIN_THREAD(getDefaultDisplayDeviceLocked());
+                                        FTL_FAKE_GUARD(mStateLock, getDefaultDisplayDeviceLocked());
 
                                 // This is a little racy, but not in a way that hurts anything. As
                                 // we grab the defaultMode from the display manager policy, we could
@@ -6043,7 +5998,7 @@
                     return mScheduler
                             ->schedule([this] {
                                 const auto display =
-                                        ON_MAIN_THREAD(getDefaultDisplayDeviceLocked());
+                                        FTL_FAKE_GUARD(mStateLock, getDefaultDisplayDeviceLocked());
                                 constexpr bool kOverridePolicy = true;
                                 return setDesiredDisplayModeSpecsInternal(display, {},
                                                                           kOverridePolicy);
@@ -6159,7 +6114,7 @@
     // Update the overlay on the main thread to avoid race conditions with
     // mRefreshRateConfigs->getActiveMode()
     static_cast<void>(mScheduler->schedule([=] {
-        const auto display = ON_MAIN_THREAD(getDefaultDisplayDeviceLocked());
+        const auto display = FTL_FAKE_GUARD(mStateLock, getDefaultDisplayDeviceLocked());
         if (!display) {
             ALOGW("%s: default display is null", __func__);
             return;
@@ -6957,7 +6912,7 @@
     }
 
     auto future = mScheduler->schedule([=]() -> status_t {
-        const auto display = ON_MAIN_THREAD(getDisplayDeviceLocked(displayToken));
+        const auto display = FTL_FAKE_GUARD(mStateLock, getDisplayDeviceLocked(displayToken));
         if (!display) {
             ALOGE("Attempt to set desired display modes for invalid display token %p",
                   displayToken.get());
@@ -7202,7 +7157,7 @@
     if (const auto frameRateOverride = mScheduler->getFrameRateOverride(uid)) {
         refreshRate = *frameRateOverride;
     } else if (!getHwComposer().isHeadless()) {
-        if (const auto display = ON_MAIN_THREAD(getDefaultDisplayDeviceLocked())) {
+        if (const auto display = FTL_FAKE_GUARD(mStateLock, getDefaultDisplayDeviceLocked())) {
             refreshRate = display->refreshRateConfigs().getActiveMode()->getFps();
         }
     }
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index f2636b4..97b0e8d 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -64,6 +64,7 @@
 #include "Scheduler/Scheduler.h"
 #include "Scheduler/VsyncModulator.h"
 #include "SurfaceFlingerFactory.h"
+#include "ThreadContext.h"
 #include "TracedOrdinal.h"
 #include "Tracing/LayerTracing.h"
 #include "Tracing/TransactionTracing.h"
@@ -183,11 +184,6 @@
     std::atomic<nsecs_t> mLastSwapTime = 0;
 };
 
-struct SCOPED_CAPABILITY UnnecessaryLock {
-    explicit UnnecessaryLock(Mutex& mutex) ACQUIRE(mutex) {}
-    ~UnnecessaryLock() RELEASE() {}
-};
-
 class SurfaceFlinger : public BnSurfaceComposer,
                        public PriorityDumper,
                        private IBinder::DeathRecipient,
@@ -740,7 +736,7 @@
     void updateLayerGeometry();
 
     void updateInputFlinger();
-    void persistDisplayBrightness(bool needsComposite) REQUIRES(SF_MAIN_THREAD);
+    void persistDisplayBrightness(bool needsComposite) REQUIRES(kMainThreadContext);
     void buildWindowInfos(std::vector<gui::WindowInfo>& outWindowInfos,
                           std::vector<gui::DisplayInfo>& outDisplayInfos);
     void commitInputWindowCommands() REQUIRES(mStateLock);
@@ -973,7 +969,7 @@
     void setCompositorTimingSnapped(const DisplayStatInfo& stats,
                                     nsecs_t compositeToPresentLatency);
 
-    void postFrame();
+    void postFrame() REQUIRES(kMainThreadContext);
 
     /*
      * Display management
@@ -1088,7 +1084,7 @@
     void clearStatsLocked(const DumpArgs& args, std::string& result);
     void dumpTimeStats(const DumpArgs& args, bool asProto, std::string& result) const;
     void dumpFrameTimeline(const DumpArgs& args, std::string& result) const;
-    void logFrameStats();
+    void logFrameStats() REQUIRES(kMainThreadContext);
 
     void dumpVSync(std::string& result) const REQUIRES(mStateLock);
     void dumpStaticScreenStats(std::string& result) const;
@@ -1431,7 +1427,7 @@
         nsecs_t commitStart;
         nsecs_t compositeStart;
         nsecs_t presentEnd;
-    } mPowerHintSessionData GUARDED_BY(SF_MAIN_THREAD);
+    } mPowerHintSessionData GUARDED_BY(kMainThreadContext);
 
     nsecs_t mAnimationTransactionTimeout = s2ns(5);
 
diff --git a/services/surfaceflinger/ThreadContext.h b/services/surfaceflinger/ThreadContext.h
new file mode 100644
index 0000000..85c379d
--- /dev/null
+++ b/services/surfaceflinger/ThreadContext.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+namespace android {
+
+// Enforces exclusive access by the main thread.
+constexpr class [[clang::capability("mutex")]] {
+} kMainThreadContext;
+
+} // namespace android
diff --git a/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h b/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h
index 1d0f62b..a80aca2 100644
--- a/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h
+++ b/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h
@@ -22,6 +22,7 @@
 #include <compositionengine/impl/CompositionEngine.h>
 #include <compositionengine/impl/Display.h>
 #include <compositionengine/impl/OutputLayerCompositionState.h>
+#include <ftl/fake_guard.h>
 #include <gui/LayerDebugInfo.h>
 #include <gui/ScreenCaptureResults.h>
 #include <gui/SurfaceComposerClient.h>
@@ -50,6 +51,7 @@
 #include "SurfaceFlinger.h"
 #include "SurfaceFlingerDefaultFactory.h"
 #include "SurfaceInterceptor.h"
+#include "ThreadContext.h"
 #include "TimeStats/TimeStats.h"
 
 #include "renderengine/mock/RenderEngine.h"
@@ -445,7 +447,7 @@
         mFlinger->clearStatsLocked(dumpArgs, result);
 
         mFlinger->dumpTimeStats(dumpArgs, fdp->ConsumeBool(), result);
-        mFlinger->logFrameStats();
+        FTL_FAKE_GUARD(kMainThreadContext, mFlinger->logFrameStats());
 
         result = fdp->ConsumeRandomLengthString().c_str();
         mFlinger->dumpFrameTimeline(dumpArgs, result);
@@ -651,7 +653,7 @@
         updateCompositorTiming(&mFdp);
 
         mFlinger->setCompositorTimingSnapped({}, mFdp.ConsumeIntegral<nsecs_t>());
-        mFlinger->postFrame();
+        FTL_FAKE_GUARD(kMainThreadContext, mFlinger->postFrame());
         mFlinger->calculateExpectedPresentTime({});
 
         mFlinger->enableHalVirtualDisplays(mFdp.ConsumeBool());
diff --git a/services/surfaceflinger/tests/unittests/DisplayDevice_SetDisplayBrightnessTest.cpp b/services/surfaceflinger/tests/unittests/DisplayDevice_SetDisplayBrightnessTest.cpp
index 73c60e1..225ad16 100644
--- a/services/surfaceflinger/tests/unittests/DisplayDevice_SetDisplayBrightnessTest.cpp
+++ b/services/surfaceflinger/tests/unittests/DisplayDevice_SetDisplayBrightnessTest.cpp
@@ -19,6 +19,7 @@
 
 #include "DisplayTransactionTestHelpers.h"
 
+#include <ftl/fake_guard.h>
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
@@ -35,7 +36,7 @@
 };
 
 TEST_F(SetDisplayBrightnessTest, persistDisplayBrightnessNoComposite) {
-    MainThreadScopedGuard fakeMainThreadGuard(SF_MAIN_THREAD);
+    ftl::FakeGuard guard(kMainThreadContext);
     sp<DisplayDevice> displayDevice = getDisplayDevice();
 
     EXPECT_EQ(std::nullopt, displayDevice->getStagedBrightness());
@@ -52,7 +53,7 @@
 }
 
 TEST_F(SetDisplayBrightnessTest, persistDisplayBrightnessWithComposite) {
-    MainThreadScopedGuard fakeMainThreadGuard(SF_MAIN_THREAD);
+    ftl::FakeGuard guard(kMainThreadContext);
     sp<DisplayDevice> displayDevice = getDisplayDevice();
 
     EXPECT_EQ(std::nullopt, displayDevice->getStagedBrightness());
@@ -70,7 +71,7 @@
 }
 
 TEST_F(SetDisplayBrightnessTest, persistDisplayBrightnessWithCompositeShortCircuitsOnNoOp) {
-    MainThreadScopedGuard fakeMainThreadGuard(SF_MAIN_THREAD);
+    ftl::FakeGuard guard(kMainThreadContext);
     sp<DisplayDevice> displayDevice = getDisplayDevice();
 
     EXPECT_EQ(std::nullopt, displayDevice->getStagedBrightness());