Kernel/Threads: Dynamically allocate the TLS region for threads in the BASE region of the linear heap.

Each thread gets a 0x200-byte area from the 0x1000-sized page, when all 8 thread slots in a single page are used up, the kernel allocates a new page to hold another 8 entries.

This is consistent with what the real kernel does.

src/core/hle/kernel/memory.cpp

@@ -109,7 +109,6 @@ struct MemoryArea {
 static MemoryArea memory_areas[] = {
     {SHARED_MEMORY_VADDR, SHARED_MEMORY_SIZE,     "Shared Memory"}, // Shared memory
     {VRAM_VADDR,          VRAM_SIZE,              "VRAM"},          // Video memory (VRAM)
-    {TLS_AREA_VADDR,      TLS_AREA_SIZE,          "TLS Area"},      // TLS memory
 };
 
 }

src/core/hle/kernel/process.h

@@ -140,8 +140,11 @@ public:
 
     MemoryRegionInfo* memory_region = nullptr;
 
-    /// Bitmask of the used TLS slots
-    std::bitset<300> used_tls_slots;
+    /// The Thread Local Storage area is allocated as processes create threads,
+    /// each TLS area is 0x200 bytes, so one page (0x1000) is split up in 8 parts, and each part
+    /// holds the TLS for a specific thread. This vector contains which parts are in use for each page as a bitmask.
+    /// This vector will grow as more pages are allocated for new threads.
+    std::vector<std::bitset<8>> tls_slots;
 
     VAddr GetLinearHeapAreaAddress() const;
     VAddr GetLinearHeapBase() const;

src/core/hle/kernel/thread.cpp

@@ -117,9 +117,10 @@ void Thread::Stop() {
     }
     wait_objects.clear();
 
-    Kernel::g_current_process->used_tls_slots[tls_index] = false;
-    g_current_process->misc_memory_used -= Memory::TLS_ENTRY_SIZE;
-    g_current_process->memory_region->used -= Memory::TLS_ENTRY_SIZE;
+    // Mark the TLS slot in the thread's page as free.
+    u32 tls_page = (tls_address - Memory::TLS_AREA_VADDR) / Memory::PAGE_SIZE;
+    u32 tls_slot = ((tls_address - Memory::TLS_AREA_VADDR) % Memory::PAGE_SIZE) / Memory::TLS_ENTRY_SIZE;
+    Kernel::g_current_process->tls_slots[tls_page].reset(tls_slot);
 
     HLE::Reschedule(__func__);
 }
@@ -366,6 +367,31 @@ static void DebugThreadQueue() {
     }
 }
 
+/**
+ * Finds a free location for the TLS section of a thread.
+ * @param tls_slots The TLS page array of the thread's owner process.
+ * Returns a tuple of (page, slot, alloc_needed) where:
+ * page: The index of the first allocated TLS page that has free slots.
+ * slot: The index of the first free slot in the indicated page.
+ * alloc_needed: Whether there's a need to allocate a new TLS page (All pages are full).
+ */
+std::tuple<u32, u32, bool> GetFreeThreadLocalSlot(std::vector<std::bitset<8>>& tls_slots) {
+    // Iterate over all the allocated pages, and try to find one where not all slots are used.
+    for (unsigned page = 0; page < tls_slots.size(); ++page) {
+        const auto& page_tls_slots = tls_slots[page];
+        if (!page_tls_slots.all()) {
+            // We found a page with at least one free slot, find which slot it is
+            for (unsigned slot = 0; slot < page_tls_slots.size(); ++slot) {
+                if (!page_tls_slots.test(slot)) {
+                    return std::make_tuple(page, slot, false);
+                }
+            }
+        }
+    }
+
+    return std::make_tuple(0, 0, true);
+}
+
 ResultVal<SharedPtr<Thread>> Thread::Create(std::string name, VAddr entry_point, s32 priority,
         u32 arg, s32 processor_id, VAddr stack_top) {
     if (priority < THREADPRIO_HIGHEST || priority > THREADPRIO_LOWEST) {
@@ -403,22 +429,50 @@ ResultVal<SharedPtr<Thread>> Thread::Create(std::string name, VAddr entry_point,
     thread->name = std::move(name);
     thread->callback_handle = wakeup_callback_handle_table.Create(thread).MoveFrom();
     thread->owner_process = g_current_process;
-    thread->tls_index = -1;
     thread->waitsynch_waited = false;
 
     // Find the next available TLS index, and mark it as used
-    auto& used_tls_slots = Kernel::g_current_process->used_tls_slots;
-    for (unsigned int i = 0; i < used_tls_slots.size(); ++i) {
-        if (used_tls_slots[i] == false) {
-            thread->tls_index = i;
-            used_tls_slots[i] = true;
-            break;
+    auto& tls_slots = Kernel::g_current_process->tls_slots;
+    bool needs_allocation = true;
+    u32 available_page; // Which allocated page has free space
+    u32 available_slot; // Which slot within the page is free
+
+    std::tie(available_page, available_slot, needs_allocation) = GetFreeThreadLocalSlot(tls_slots);
+
+    if (needs_allocation) {
+        // There are no already-allocated pages with free slots, lets allocate a new one.
+        // TLS pages are allocated from the BASE region in the linear heap.
+        MemoryRegionInfo* memory_region = GetMemoryRegion(MemoryRegion::BASE);
+        auto& linheap_memory = memory_region->linear_heap_memory;
+
+        if (linheap_memory->size() + Memory::PAGE_SIZE > memory_region->size) {
+            LOG_ERROR(Kernel_SVC, "Not enough space in region to allocate a new TLS page for thread");
+            return ResultCode(ErrorDescription::OutOfMemory, ErrorModule::Kernel, ErrorSummary::OutOfResource, ErrorLevel::Permanent);
         }
+
+        u32 offset = linheap_memory->size();
+
+        // Allocate some memory from the end of the linear heap for this region.
+        linheap_memory->insert(linheap_memory->end(), Memory::PAGE_SIZE, 0);
+        memory_region->used += Memory::PAGE_SIZE;
+        Kernel::g_current_process->linear_heap_used += Memory::PAGE_SIZE;
+
+        tls_slots.emplace_back(0); // The page is completely available at the start
+        available_page = tls_slots.size() - 1;
+        available_slot = 0; // Use the first slot in the new page
+
+        auto& vm_manager = Kernel::g_current_process->vm_manager;
+        vm_manager.RefreshMemoryBlockMappings(linheap_memory.get());
+
+        // Map the page to the current process' address space.
+        // TODO(Subv): Find the correct MemoryState for this region.
+        vm_manager.MapMemoryBlock(Memory::TLS_AREA_VADDR + available_page * Memory::PAGE_SIZE,
+                                  linheap_memory, offset, Memory::PAGE_SIZE, MemoryState::Private);
     }
 
-    ASSERT_MSG(thread->tls_index != -1, "Out of TLS space");
-    g_current_process->misc_memory_used += Memory::TLS_ENTRY_SIZE;
-    g_current_process->memory_region->used += Memory::TLS_ENTRY_SIZE;
+    // Mark the slot as used
+    tls_slots[available_page].set(available_slot);
+    thread->tls_address = Memory::TLS_AREA_VADDR + available_page * Memory::PAGE_SIZE + available_slot * Memory::TLS_ENTRY_SIZE;
 
     // TODO(peachum): move to ScheduleThread() when scheduler is added so selected core is used
     // to initialize the context
@@ -508,10 +562,6 @@ void Thread::SetWaitSynchronizationOutput(s32 output) {
     context.cpu_registers[1] = output;
 }
 
-VAddr Thread::GetTLSAddress() const {
-    return Memory::TLS_AREA_VADDR + tls_index * Memory::TLS_ENTRY_SIZE;
-}
-
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 void ThreadingInit() {

src/core/hle/kernel/thread.h

@@ -127,7 +127,7 @@ public:
      * Returns the Thread Local Storage address of the current thread
      * @returns VAddr of the thread's TLS
      */
-    VAddr GetTLSAddress() const;
+    VAddr GetTLSAddress() const { return tls_address; }
 
     Core::ThreadContext context;
 
@@ -144,7 +144,7 @@ public:
 
     s32 processor_id;
 
-    s32 tls_index; ///< Index of the Thread Local Storage of the thread
+    VAddr tls_address; ///< Virtual address of the Thread Local Storage of the thread
 
     bool waitsynch_waited; ///< Set to true if the last svcWaitSynch call caused the thread to wait
 

src/core/memory.h

@@ -100,15 +100,9 @@ enum : VAddr {
     SHARED_PAGE_SIZE      = 0x00001000,
     SHARED_PAGE_VADDR_END = SHARED_PAGE_VADDR + SHARED_PAGE_SIZE,
 
-    // TODO(yuriks): The size of this area is dynamic, the kernel grows
-    // it as more and more threads are created. For now we'll just use a
-    // hardcoded value.
     /// Area where TLS (Thread-Local Storage) buffers are allocated.
     TLS_AREA_VADDR     = 0x1FF82000,
     TLS_ENTRY_SIZE     = 0x200,
-    TLS_AREA_SIZE      = 300 * TLS_ENTRY_SIZE + 0x800, // Space for up to 300 threads + round to page size
-    TLS_AREA_VADDR_END = TLS_AREA_VADDR + TLS_AREA_SIZE,
-
 
     /// Equivalent to LINEAR_HEAP_VADDR, but expanded to cover the extra memory in the New 3DS.
     NEW_LINEAR_HEAP_VADDR     = 0x30000000,