JVM Auto-Attach + Fix Thread Exiting + Fix Thread Signal Handler

app/src/main/cpp/skyline/jvm.cpp

@@ -3,30 +3,53 @@
 
 #include "jvm.h"
 
-thread_local JNIEnv *env;
-
 namespace skyline {
-    JvmManager::JvmManager(JNIEnv *environ, jobject instance) : instance(environ->NewGlobalRef(instance)), instanceClass(reinterpret_cast<jclass>(environ->NewGlobalRef(environ->GetObjectClass(instance)))), initializeControllersId(environ->GetMethodID(instanceClass, "initializeControllers", "()V")), vibrateDeviceId(environ->GetMethodID(instanceClass, "vibrateDevice", "(I[J[I)V")), clearVibrationDeviceId(environ->GetMethodID(instanceClass, "clearVibrationDevice", "(I)V")) {
+    /*
-        env = environ;
+     * @brief A thread-local wrapper over JNIEnv and JavaVM which automatically handles attaching and detaching threads
+     */
+    struct JniEnvironment {
+        static inline JNIEnv *env{};
+        static inline JavaVM *vm{};
+        bool attached{};
+
+        JniEnvironment(JNIEnv *environment) {
+            env = environment;
             if (env->GetJavaVM(&vm) < 0)
                 throw exception("Cannot get JavaVM from environment");
         }
 
+        JniEnvironment() {
+            if (vm) {
+                vm->AttachCurrentThread(&env, nullptr);
+                attached = true;
+            }
+        }
+
+        ~JniEnvironment() {
+            if (vm && attached)
+                vm->DetachCurrentThread();
+        }
+
+        operator JNIEnv *() {
+            return env;
+        }
+
+        JNIEnv* operator->() {
+            return env;
+        }
+    };
+
+    thread_local inline JniEnvironment env;
+
+    JvmManager::JvmManager(JNIEnv *environ, jobject instance) : instance(environ->NewGlobalRef(instance)), instanceClass(reinterpret_cast<jclass>(environ->NewGlobalRef(environ->GetObjectClass(instance)))), initializeControllersId(environ->GetMethodID(instanceClass, "initializeControllers", "()V")), vibrateDeviceId(environ->GetMethodID(instanceClass, "vibrateDevice", "(I[J[I)V")), clearVibrationDeviceId(environ->GetMethodID(instanceClass, "clearVibrationDevice", "(I)V")) {
+        env = JniEnvironment(environ);
+    }
+
     JvmManager::~JvmManager() {
         env->DeleteGlobalRef(instanceClass);
         env->DeleteGlobalRef(instance);
     }
 
-    void JvmManager::AttachThread() {
-        if (!env)
-            vm->AttachCurrentThread(&env, nullptr);
-    }
-
-    void JvmManager::DetachThread() {
-        if (env)
-            vm->DetachCurrentThread();
-    }
-
     JNIEnv *JvmManager::GetEnv() {
         return env;
     }

app/src/main/cpp/skyline/jvm.h

@@ -12,7 +12,6 @@ namespace skyline {
      */
     class JvmManager {
       public:
-        JavaVM *vm{}; //!< A pointer to the Java VM
         jobject instance; //!< A reference to the activity
         jclass instanceClass; //!< The class of the activity
 
@@ -24,16 +23,6 @@ namespace skyline {
 
         ~JvmManager();
 
-        /**
-         * @brief Attach the current thread to the Java VM
-         */
-        void AttachThread();
-
-        /**
-         * @brief Detach the current thread to the Java VM
-         */
-        void DetachThread();
-
         /**
          * @brief Returns a pointer to the JNI environment for the current thread
          */

app/src/main/cpp/skyline/kernel/memory.cpp

@@ -141,16 +141,22 @@ namespace skyline::kernel {
             if (lower->size) {
                 upper = chunks.insert(upper, lowerExtension);
                 chunks.insert(upper, chunk);
+            } else {
+                auto lower2{std::prev(lower)};
+                if (chunk.IsCompatible(*lower2) && lower2->ptr + lower2->size >= chunk.ptr) {
+                    lower2->size = chunk.ptr + chunk.size - lower2->ptr;
+                    upper = chunks.erase(lower);
                 } else {
                     *lower = chunk;
-                chunks.insert(upper, lowerExtension);
                 }
-        } else if (chunk.IsCompatible(*lower)) {
+                upper = chunks.insert(upper, lowerExtension);
-            lower->size = std::max(lower->ptr + lower->size, chunk.ptr + chunk.size) - lower->ptr;
+            }
+        } else if (chunk.IsCompatible(*lower) && lower->ptr + lower->size >= chunk.ptr) {
+            lower->size = chunk.ptr + chunk.size - lower->ptr;
         } else {
             if (lower->ptr + lower->size > chunk.ptr)
                 lower->size = chunk.ptr - lower->ptr;
-            if (upper != chunks.end() && chunk.IsCompatible(*upper)) {
+            if (upper != chunks.end() && chunk.IsCompatible(*upper) && chunk.ptr + chunk.size >= upper->ptr) {
                 upper->ptr = chunk.ptr;
                 upper->size = chunk.size + upper->size;
             } else {
@@ -170,7 +176,7 @@ namespace skyline::kernel {
         return std::nullopt;
     }
 
-    size_t MemoryManager::GetProgramSize() {
+    size_t MemoryManager::GetMemoryUsage() {
         size_t size{};
         for (const auto &chunk : chunks)
             if (chunk.state != memory::states::Unmapped)

app/src/main/cpp/skyline/kernel/memory.h

@@ -53,7 +53,7 @@ namespace skyline {
                 bool isDeviceShared : 1; //!< True when DeviceRefCount > 0
                 bool isUncached     : 1; //!< This is used to disable memory caching to share memory with the GPU
             };
-            u32 value;
+            u32 value{};
         };
 
         /**
@@ -137,7 +137,7 @@ namespace skyline {
                 bool attributeChangeAllowed : 1; //!< If the application can use svcSetMemoryAttribute on this block
                 bool codeMemoryAllowed : 1; //!< If the application can use svcCreateCodeMemory on this block
             };
-            u32 value;
+            u32 value{};
         };
         static_assert(sizeof(MemoryState) == sizeof(u32));
 
@@ -239,7 +239,7 @@ namespace skyline {
             /**
              * @return The cumulative size of all memory mappings in bytes
              */
-            size_t GetProgramSize();
+            size_t GetMemoryUsage();
         };
     }
 }

app/src/main/cpp/skyline/kernel/svc.cpp

@@ -24,7 +24,7 @@ namespace skyline::kernel::svc {
         state.ctx->gpr.w0 = Result{};
         state.ctx->gpr.x1 = reinterpret_cast<u64>(heap->ptr);
 
-        state.logger->Debug("svcSetHeapSize: Allocated at {} for 0x{:X} bytes", heap->ptr, heap->size);
+        state.logger->Debug("svcSetHeapSize: Allocated at 0x{:X} - 0x{:X} (0x{:X} bytes)", heap->ptr, heap->ptr + heap->size, heap->size);
     }
 
     void SetMemoryAttribute(const DeviceState &state) {
@@ -71,7 +71,7 @@ namespace skyline::kernel::svc {
         newChunk.attributes.isUncached = value.isUncached;
         state.process->memory.InsertChunk(newChunk);
 
-        state.logger->Debug("svcSetMemoryAttribute: Set caching to {} at 0x{:X} for 0x{:X} bytes", static_cast<bool>(value.isUncached), pointer, size);
+        state.logger->Debug("svcSetMemoryAttribute: Set caching to {} at 0x{:X} - 0x{:X} (0x{:X} bytes)", static_cast<bool>(value.isUncached), pointer, pointer + size, size);
         state.ctx->gpr.w0 = Result{};
     }
 
@@ -216,7 +216,7 @@ namespace skyline::kernel::svc {
 
     void ExitProcess(const DeviceState &state) {
         state.logger->Debug("svcExitProcess: Exiting process");
-        //state.os->KillThread(state.process->pid);
+        exit(0);
     }
 
     void CreateThread(const DeviceState &state) {
@@ -235,7 +235,7 @@ namespace skyline::kernel::svc {
         if (!stack)
             throw exception("svcCreateThread: Cannot find memory object in handle table for thread stack: 0x{:X}", stackTop);
 
-        auto thread{state.process->CreateThread(entry, entryArgument, priority, static_pointer_cast<type::KPrivateMemory>(stack->item))};
+        auto thread{state.process->CreateThread(entry, entryArgument, stackTop, priority)};
         state.logger->Debug("svcCreateThread: Created thread with handle 0x{:X} (Entry Point: 0x{:X}, Argument: 0x{:X}, Stack Pointer: 0x{:X}, Priority: {}, ID: {})", thread->handle, entry, entryArgument, stackTop, priority, thread->id);
 
         state.ctx->gpr.w1 = thread->handle;
@@ -257,7 +257,8 @@ namespace skyline::kernel::svc {
 
     void ExitThread(const DeviceState &state) {
         state.logger->Debug("svcExitThread: Exiting current thread: {}", state.thread->id);
-        state.os->KillThread(state.thread->id);
+        state.thread->Kill();
+        pthread_exit(nullptr);
     }
 
     void SleepThread(const DeviceState &state) {
@@ -338,7 +339,7 @@ namespace skyline::kernel::svc {
                 return;
             }
 
-            state.logger->Debug("svcMapSharedMemory: Mapping shared memory at 0x{:X} for {} bytes ({}{}{})", pointer, size, permission.r ? 'R' : '-', permission.w ? 'W' : '-', permission.x ? 'X' : '-');
+            state.logger->Debug("svcMapSharedMemory: Mapping shared memory at 0x{:X} - 0x{:X} (0x{:X} bytes) ({}{}{})", pointer, pointer + size, size, permission.r ? 'R' : '-', permission.w ? 'W' : '-', permission.x ? 'X' : '-');
 
             object->Map(pointer, size, permission);
 
@@ -372,7 +373,7 @@ namespace skyline::kernel::svc {
         }
 
         auto tmem{state.process->NewHandle<type::KTransferMemory>(pointer, size, permission)};
-        state.logger->Debug("svcCreateTransferMemory: Creating transfer memory at 0x{:X} for {} bytes ({}{}{})", pointer, size, permission.r ? 'R' : '-', permission.w ? 'W' : '-', permission.x ? 'X' : '-');
+        state.logger->Debug("svcCreateTransferMemory: Creating transfer memory at 0x{:X} - 0x{:X} (0x{:X} bytes) ({}{}{})", pointer, pointer + size, size, permission.r ? 'R' : '-', permission.w ? 'W' : '-', permission.x ? 'X' : '-');
 
         state.ctx->gpr.w0 = Result{};
         state.ctx->gpr.w1 = tmem.handle;
@@ -674,7 +675,7 @@ namespace skyline::kernel::svc {
                 break;
 
             case constant::infoState::TotalMemoryUsage:
-                out = state.process->heap->size + state.thread->stack->size + state.process->memory.GetProgramSize();
+                out = state.process->memory.GetMemoryUsage();
                 break;
 
             case constant::infoState::AddressSpaceBaseAddr:
@@ -698,7 +699,7 @@ namespace skyline::kernel::svc {
                 break;
 
             case constant::infoState::PersonalMmHeapUsage:
-                out = state.process->heap->size + state.thread->stack->size;
+                out = state.process->heap->size + state.process->mainThreadStack->size;
                 break;
 
             case constant::infoState::TotalMemoryAvailableWithoutMmHeap:
@@ -706,7 +707,7 @@ namespace skyline::kernel::svc {
                 break;
 
             case constant::infoState::TotalMemoryUsedWithoutMmHeap:
-                out = state.process->heap->size + state.thread->stack->size; // TODO: Same as above
+                out = state.process->heap->size + state.process->mainThreadStack->size; // TODO: Same as above
                 break;
 
             case constant::infoState::UserExceptionContextAddr:

app/src/main/cpp/skyline/kernel/types/KPrivateMemory.cpp

@@ -11,8 +11,8 @@ namespace skyline::kernel::type {
     KPrivateMemory::KPrivateMemory(const DeviceState &state, u8* ptr, size_t size, memory::Permission permission, memory::MemoryState memState) : ptr(ptr), size(size), permission(permission), memState(memState), KMemory(state, KType::KPrivateMemory) {
         if (!state.process->memory.base.IsInside(ptr) || !state.process->memory.base.IsInside(ptr + size))
             throw exception("KPrivateMemory allocation isn't inside guest address space: 0x{:X} - 0x{:X}", ptr, ptr + size);
-        if (!util::PageAligned(ptr))
+        if (!util::PageAligned(ptr) || !util::PageAligned(size))
-            throw exception("KPrivateMemory was created with non-page-aligned address: 0x{:X}", ptr);
+            throw exception("KPrivateMemory mapping isn't page-aligned: 0x{:X} - 0x{:X} (0x{:X})", ptr, ptr + size, size);
 
         if (mprotect(ptr, size, PROT_READ | PROT_WRITE | PROT_EXEC) < 0) // We only need to reprotect as the allocation has already been reserved by the MemoryManager
             throw exception("An occurred while mapping private memory: {} with 0x{:X} @ 0x{:X}", strerror(errno), ptr, size);

app/src/main/cpp/skyline/kernel/types/KProcess.cpp

@@ -49,8 +49,15 @@ namespace skyline::kernel::type {
         return tlsPage->ReserveSlot();
     }
 
-    std::shared_ptr<KThread> KProcess::CreateThread(void *entry, u64 argument, i8 priority, const std::shared_ptr<KPrivateMemory> &stack) {
+    std::shared_ptr<KThread> KProcess::CreateThread(void *entry, u64 argument, void *stackTop, i8 priority) {
-        auto thread{NewHandle<KThread>(this, threads.size(), entry, argument, priority, stack).item};
+        if (!stackTop && threads.empty()) { //!< Main thread stack is created by the kernel and owned by the process
+            constexpr u64 DefaultStackSize{0x200000}; //!< The default amount of stack: 2 MB
+            mainThreadStack = mainThreadStack.make_shared(state, reinterpret_cast<u8 *>(state.process->memory.stack.address), DefaultStackSize, memory::Permission{true, true, false}, memory::states::Stack);
+            if (mprotect(mainThreadStack->ptr, PAGE_SIZE, PROT_NONE))
+                throw exception("Failed to create guard page for thread stack at 0x{:X}", mainThreadStack->ptr);
+            stackTop = mainThreadStack->ptr + mainThreadStack->size;
+        }
+        auto thread{NewHandle<KThread>(this, threads.size(), entry, argument, stackTop, priority).item};
         threads.push_back(thread);
         return thread;
     }

app/src/main/cpp/skyline/kernel/types/KProcess.h

@@ -64,6 +64,7 @@ namespace skyline {
 
           public:
             MemoryManager memory;
+            std::shared_ptr<KPrivateMemory> mainThreadStack;
             std::shared_ptr<KPrivateMemory> heap;
             std::vector<std::shared_ptr<KThread>> threads;
             std::vector<std::shared_ptr<TlsPage>> tlsPages;
@@ -80,7 +81,7 @@ namespace skyline {
              */
             u8* AllocateTlsSlot();
 
-            std::shared_ptr<KThread> CreateThread(void *entry, u64 argument = 0, i8 priority = 44, const std::shared_ptr<KPrivateMemory> &stack = nullptr);
+            std::shared_ptr<KThread> CreateThread(void *entry, u64 argument = 0, void *stackTop = nullptr, i8 priority = constant::DefaultPriority);
 
             /**
             * @brief The output for functions that return created kernel objects

app/src/main/cpp/skyline/kernel/types/KSharedMemory.cpp

@@ -23,8 +23,8 @@ namespace skyline::kernel::type {
     u8 *KSharedMemory::Map(u8 *ptr, u64 size, memory::Permission permission) {
         if (!state.process->memory.base.IsInside(ptr) || !state.process->memory.base.IsInside(ptr + size))
             throw exception("KPrivateMemory allocation isn't inside guest address space: 0x{:X} - 0x{:X}", ptr, ptr + size);
-        if (ptr && !util::PageAligned(ptr))
+        if (!util::PageAligned(ptr) || !util::PageAligned(size))
-            throw exception("KSharedMemory was mapped to a non-page-aligned address: 0x{:X}", ptr);
+            throw exception("KSharedMemory mapping isn't page-aligned: 0x{:X} - 0x{:X} (0x{:X})", ptr, ptr + size, size);
 
         guest.ptr = reinterpret_cast<u8 *>(mmap(ptr, size, permission.Get(), MAP_SHARED | (ptr ? MAP_FIXED : 0), fd, 0));
         if (guest.ptr == MAP_FAILED)

app/src/main/cpp/skyline/kernel/types/KThread.cpp

@@ -4,12 +4,15 @@
 #include <sys/types.h>
 #include <sys/resource.h>
 #include <unistd.h>
+#include <asm/unistd.h>
 #include <nce.h>
 #include <os.h>
+#include <android/log.h>
+#include <dlfcn.h>
 #include "KProcess.h"
 
 namespace skyline::kernel::type {
-    KThread::KThread(const DeviceState &state, KHandle handle, KProcess *parent, size_t id, void *entry, u64 argument, i8 priority, const std::shared_ptr<KPrivateMemory> &stack) : handle(handle), parent(parent), id(id), entry(entry), entryArgument(argument), stack(stack), KSyncObject(state, KType::KThread) {
+    KThread::KThread(const DeviceState &state, KHandle handle, KProcess *parent, size_t id, void *entry, u64 argument, void *stackTop, i8 priority) : handle(handle), parent(parent), id(id), entry(entry), entryArgument(argument), stackTop(stackTop), KSyncObject(state, KType::KThread) {
         UpdatePriority(priority);
     }
 
@@ -17,6 +20,24 @@ namespace skyline::kernel::type {
         Kill();
     }
 
+    /**
+     * @brief Our delegator for sigaction, we need to do this due to sigchain hooking bionic's sigaction and it intercepting signals before they're passed onto userspace
+     * This not only leads to performance degradation but also requires host TLS to be in the TLS register which we cannot ensure for in-guest signals
+     */
+    inline void Sigaction(int signal, const struct sigaction &action, struct sigaction *oldAction = nullptr) {
+        static decltype(&sigaction) realSigaction{};
+        if (!realSigaction) {
+            void *libc{dlopen("libc.so", RTLD_LOCAL | RTLD_LAZY)};
+            if (!libc)
+                throw exception("dlopen-ing libc has failed with: {}", dlerror());
+            realSigaction = reinterpret_cast<decltype(&sigaction)>(dlsym(libc, "sigaction"));
+            if (!realSigaction)
+                throw exception("Cannot find 'sigaction' in libc: {}", dlerror());
+        }
+        if (realSigaction(signal, &action, oldAction) < 0)
+            throw exception("sigaction has failed with {}", strerror(errno));
+    }
+
     void KThread::StartThread() {
         pthread_setname_np(pthread_self(), fmt::format("HOS-{}", id).c_str());
 
@@ -31,9 +52,8 @@ namespace skyline::kernel::type {
             .sa_sigaction = &nce::NCE::SignalHandler,
             .sa_flags = SA_SIGINFO,
         };
-
+        for (int signal : {SIGILL, SIGTRAP, SIGBUS, SIGFPE, SIGSEGV})
-        //for (int signal : {SIGILL, SIGTRAP, SIGBUS, SIGFPE, SIGSEGV})
+            Sigaction(signal, sigact);
-         //   sigaction(signal, &sigact, nullptr);
 
         asm volatile(
         "MRS X0, TPIDR_EL0\n\t"
@@ -109,7 +129,7 @@ namespace skyline::kernel::type {
         "DUP V31.16B, WZR\n\t"
         "RET"
         :
-        : "r"(&ctx), "r"(stack->ptr + stack->size), "r"(entry), "r"(entryArgument), "r"(handle)
+        : "r"(&ctx), "r"(stackTop), "r"(entry), "r"(entryArgument), "r"(handle)
         : "x0", "x1", "lr"
         );
 
@@ -119,16 +139,7 @@ namespace skyline::kernel::type {
     void KThread::Start(bool self) {
         if (!running) {
             running = true;
-
             state.logger->Debug("Starting thread #{}", id);
-
-            if (!stack) {
-                constexpr u64 DefaultStackSize{0x1E8480}; //!< The default amount of stack: 2 MB
-                stack = stack.make_shared(state, reinterpret_cast<u8 *>(state.process->memory.stack.address), DefaultStackSize, memory::Permission{true, true, false}, memory::states::Stack);
-                if (mprotect(stack->ptr, PAGE_SIZE, PROT_NONE))
-                    throw exception("Failed to create guard page for thread stack at 0x{:X}", stack->ptr);
-            }
-
             if (self)
                 StartThread();
             else
@@ -139,10 +150,7 @@ namespace skyline::kernel::type {
     void KThread::Kill() {
         if (running) {
             running = false;
-
             Signal();
-            exit(0);
-            //tgkill(gettgid(), tid, SIGTERM);
         }
     }
 

app/src/main/cpp/skyline/kernel/types/KThread.h

@@ -51,20 +51,20 @@ namespace skyline {
             void StartThread();
 
           public:
-            std::atomic<bool> running{false};
+            bool running{false};
             std::atomic<bool> cancelSync{false}; //!< This is to flag to a thread to cancel a synchronization call it currently is in
 
             KHandle handle;
             size_t id; //!< Index of thread in parent process's KThread vector
 
-            std::shared_ptr<KPrivateMemory> stack;
             nce::ThreadContext ctx{};
 
             void* entry;
             u64 entryArgument;
+            void* stackTop;
             i8 priority;
 
-            KThread(const DeviceState &state, KHandle handle, KProcess *parent, size_t id, void *entry, u64 argument = 0, i8 priority = constant::DefaultPriority, const std::shared_ptr<KPrivateMemory>& stack = nullptr);
+            KThread(const DeviceState &state, KHandle handle, KProcess *parent, size_t id, void *entry, u64 argument, void *stackTop, i8 priority = constant::DefaultPriority);
 
             ~KThread();
 
@@ -75,6 +75,10 @@ namespace skyline {
              */
             void Start(bool self = false);
 
+            /**
+             * @brief Updates the internal state of the thread to signal it being dead
+             * @note This should only be called by the host thread running this guest thread
+             */
             void Kill();
 
             /**

app/src/main/cpp/skyline/os.cpp

@@ -36,17 +36,4 @@ namespace skyline::kernel {
 
         state.nce->Execute();
     }
-
-    void OS::KillThread(pid_t pid) {
-        /*
-        if (process->pid == pid) {
-            state.logger->Debug("Killing process with PID: {}", pid);
-            for (auto &thread: process->threads)
-                thread.second->Kill();
-        } else {
-            state.logger->Debug("Killing thread with TID: {}", pid);
-            process->threads.at(pid)->Kill();
-        }
-         */
-    }
 }

app/src/main/cpp/skyline/os.h

@@ -39,11 +39,5 @@ namespace skyline::kernel {
          * @return An instance of the KProcess of the created process
          */
         std::shared_ptr<type::KProcess> CreateProcess(u64 entry, u64 argument, size_t stackSize);
-
-        /**
-         * @brief Kill a particular thread
-         * @param pid The PID of the thread
-         */
-        void KillThread(pid_t pid);
     };
 }

app/src/main/cpp/skyline/services/am/storage/IStorageAccessor.cpp

@@ -20,7 +20,7 @@ namespace skyline::service::am {
             return result::OutOfBounds;
 
         if (size)
-            request.outputBuf.at(0).copy_from(span(parent->content.data() + offset, size));
+            span(parent->content).copy_from(request.outputBuf.at(0), size);
 
         return {};
     }

app/src/main/cpp/skyline/services/hosbinder/GraphicBufferProducer.cpp

@@ -124,16 +124,18 @@ namespace skyline::service::hosbinder {
         auto nvmap{driver->nvMap.lock()};
 
         if (gbpBuffer.nvmapHandle) {
-            nvBuffer = nvmap->handleTable.at(gbpBuffer.nvmapHandle);
+            nvBuffer = nvmap->GetObject(gbpBuffer.nvmapHandle);
         } else {
-            for (const auto &object : nvmap->handleTable) {
+            std::shared_lock nvmapLock(nvmap->mapMutex);
-                if (object.second->id == gbpBuffer.nvmapId) {
+            for (const auto &object : nvmap->maps) {
-                    nvBuffer = object.second;
+                if (object->id == gbpBuffer.nvmapId) {
+                    nvBuffer = object;
                     break;
                 }
             }
             if (!nvBuffer)
                 throw exception("A QueueBuffer request has an invalid NVMap Handle ({}) and ID ({})", gbpBuffer.nvmapHandle, gbpBuffer.nvmapId);
+            nvmapLock.unlock();
         }
 
         gpu::texture::Format format;
@@ -187,9 +189,6 @@ namespace skyline::service::hosbinder {
         }
     }
 
-    /**
-     * @brief A mapping from a display's name to it's displayType entry
-     */
     static frz::unordered_map<frz::string, DisplayId, 5> DisplayTypeMap{
         {"Default", DisplayId::Default},
         {"External", DisplayId::External},

app/src/main/cpp/skyline/services/nvdrv/devices/nvhost_as_gpu.cpp

@@ -81,7 +81,7 @@ namespace skyline::service::nvdrv::device {
         try {
             auto driver{nvdrv::driver.lock()};
             auto nvmap{driver->nvMap.lock()};
-            auto mapping{nvmap->handleTable.at(data.nvmapHandle)};
+            auto mapping{nvmap->GetObject(data.nvmapHandle)};
 
             if (data.flags.remap) {
                 auto region{regionMap.upper_bound(data.offset)};
@@ -180,7 +180,7 @@ namespace skyline::service::nvdrv::device {
             try {
                 auto driver{nvdrv::driver.lock()};
                 auto nvmap{driver->nvMap.lock()};
-                auto mapping{nvmap->handleTable.at(entry.nvmapHandle)};
+                auto mapping{nvmap->GetObject(entry.nvmapHandle)};
 
                 u64 mapAddress{static_cast<u64>(entry.gpuOffset) << MinAlignmentShift};
                 u8* mapPointer{mapping->pointer + (static_cast<u64>(entry.mapOffset) << MinAlignmentShift)};

app/src/main/cpp/skyline/services/nvdrv/devices/nvmap.cpp

@@ -14,8 +14,9 @@ namespace skyline::service::nvdrv::device {
             u32 handle; // Out
         } &data = buffer.as<Data>();
 
-        handleTable[handleIndex] = std::make_shared<NvMapObject>(idIndex++, data.size);
+        std::unique_lock lock(mapMutex);
-        data.handle = handleIndex++;
+        maps.push_back(std::make_shared<NvMapObject>(idIndex++, data.size));
+        data.handle = maps.size();
 
         state.logger->Debug("Size: 0x{:X} -> Handle: 0x{:X}", data.size, data.handle);
         return NvStatus::Success;
@@ -27,9 +28,10 @@ namespace skyline::service::nvdrv::device {
             u32 handle; // Out
         } &data = buffer.as<Data>();
 
-        for (const auto &object : handleTable) {
+        std::shared_lock lock(mapMutex);
-            if (object.second->id == data.id) {
+        for (auto it{maps.begin()}; it < maps.end(); it++) {
-                data.handle = object.first;
+            if ((*it)->id == data.id) {
+                data.handle = (it - maps.begin()) + 1;
                 state.logger->Debug("ID: 0x{:X} -> Handle: 0x{:X}", data.id, data.handle);
                 return NvStatus::Success;
             }
@@ -51,7 +53,7 @@ namespace skyline::service::nvdrv::device {
         } &data = buffer.as<Data>();
 
         try {
-            auto &object{handleTable.at(data.handle)};
+            auto object{GetObject(data.handle)};
             object->heapMask = data.heapMask;
             object->flags = data.flags;
             object->align = data.align;
@@ -76,8 +78,9 @@ namespace skyline::service::nvdrv::device {
             u32 flags;    // Out
         } &data = buffer.as<Data>();
 
+        std::unique_lock lock(mapMutex);
         try {
-            const auto &object{handleTable.at(data.handle)};
+            auto &object{maps.at(data.handle)};
             if (object.use_count() > 1) {
                 data.pointer = object->pointer;
                 data.flags = 0x0;
@@ -87,7 +90,7 @@ namespace skyline::service::nvdrv::device {
             }
 
             data.size = object->size;
-            handleTable.erase(data.handle);
+            object = nullptr;
 
             state.logger->Debug("Handle: 0x{:X} -> Pointer: 0x{:X}, Size: 0x{:X}, Flags: 0x{:X}", data.handle, data.pointer, data.size, data.flags);
             return NvStatus::Success;
@@ -115,7 +118,7 @@ namespace skyline::service::nvdrv::device {
         } &data = buffer.as<Data>();
 
         try {
-            auto &object{handleTable.at(data.handle)};
+            auto object{GetObject(data.handle)};
 
             switch (data.parameter) {
                 case Parameter::Size:
@@ -158,7 +161,7 @@ namespace skyline::service::nvdrv::device {
         } &data = buffer.as<Data>();
 
         try {
-            data.id = handleTable.at(data.handle)->id;
+            data.id = GetObject(data.handle)->id;
             state.logger->Debug("Handle: 0x{:X} -> ID: 0x{:X}", data.handle, data.id);
             return NvStatus::Success;
         } catch (const std::out_of_range &) {

app/src/main/cpp/skyline/services/nvdrv/devices/nvmap.h

@@ -32,12 +32,23 @@ namespace skyline::service::nvdrv::device {
             NvMapObject(u32 id, u32 size);
         };
 
-        std::unordered_map<KHandle, std::shared_ptr<NvMapObject>> handleTable; //!< A mapping from a handle to it's corresponding NvMapObject
+        std::shared_mutex mapMutex; //!< Synchronizes mutations and accesses of the mappings
-        KHandle handleIndex{1}; //!< This is used to keep track of the next handle to allocate
+        std::vector<std::shared_ptr<NvMapObject>> maps;
+
         u32 idIndex{1}; //!< This is used to keep track of the next ID to allocate
 
         NvMap(const DeviceState &state);
 
+        inline std::shared_ptr<NvMapObject> GetObject(u32 handle) {
+            if (handle-- == 0)
+                throw std::out_of_range("0 is an invalid nvmap handle");
+            std::shared_lock lock(mapMutex);
+            auto& object{maps.at(handle)};
+            if (!object)
+                throw std::out_of_range("A freed nvmap handle was requested");
+            return object;
+        }
+
         /**
          * @brief Creates an NvMapObject and returns an handle to it
          * @url https://switchbrew.org/wiki/NV_services#NVMAP_IOC_CREATE