kernel/process: Move main thread stack allocation to its own function

Keeps this particular set of behavior isolated to its own function.

src/core/hle/kernel/process.cpp

@@ -186,19 +186,9 @@ ResultCode Process::LoadFromMetadata(const FileSys::ProgramMetadata& metadata) {
 }
 
 void Process::Run(s32 main_thread_priority, u64 stack_size) {
-    // The kernel always ensures that the given stack size is page aligned.
-    main_thread_stack_size = Common::AlignUp(stack_size, Memory::PAGE_SIZE);
-
-    // Allocate and map the main thread stack
-    // TODO(bunnei): This is heap area that should be allocated by the kernel and not mapped as part
-    // of the user address space.
-    const VAddr mapping_address = vm_manager.GetTLSIORegionEndAddress() - main_thread_stack_size;
-    vm_manager
-        .MapMemoryBlock(mapping_address, std::make_shared<std::vector<u8>>(main_thread_stack_size),
-                        0, main_thread_stack_size, MemoryState::Stack)
-        .Unwrap();
-
+    AllocateMainThreadStack(stack_size);
     vm_manager.LogLayout();
+
     ChangeStatus(ProcessStatus::Running);
 
     SetupMainThread(*this, kernel, main_thread_priority);
@@ -327,4 +317,16 @@ void Process::ChangeStatus(ProcessStatus new_status) {
     WakeupAllWaitingThreads();
 }
 
+void Process::AllocateMainThreadStack(u64 stack_size) {
+    // The kernel always ensures that the given stack size is page aligned.
+    main_thread_stack_size = Common::AlignUp(stack_size, Memory::PAGE_SIZE);
+
+    // Allocate and map the main thread stack
+    const VAddr mapping_address = vm_manager.GetTLSIORegionEndAddress() - main_thread_stack_size;
+    vm_manager
+        .MapMemoryBlock(mapping_address, std::make_shared<std::vector<u8>>(main_thread_stack_size),
+                        0, main_thread_stack_size, MemoryState::Stack)
+        .Unwrap();
+}
+
 } // namespace Kernel

src/core/hle/kernel/process.h

@@ -280,6 +280,9 @@ private:
     /// a process signal.
     void ChangeStatus(ProcessStatus new_status);
 
+    /// Allocates the main thread stack for the process, given the stack size in bytes.
+    void AllocateMainThreadStack(u64 stack_size);
+
     /// Memory manager for this process.
     Kernel::VMManager vm_manager;