[rpcsx-os] fork: implement vm and vfs fork

stub metadbg device
implement notification device
implement sys_pipe

orbis-kernel/include/orbis/KernelContext.hpp

@@ -1,6 +1,7 @@
 #pragma once
 #include "evf.hpp"
 #include "ipmi.hpp"
+#include "orbis/utils/IdMap.hpp"
 #include "osem.hpp"
 #include "utils/LinkedNode.hpp"
 #include "utils/SharedCV.hpp"
@@ -54,6 +55,15 @@ public:
   void deleteProcess(Process *proc);
   Process *findProcessById(pid_t pid) const;
 
+  utils::LinkedNode<Process> *getProcessList() {
+    return m_processes;
+  }
+
+  long allocatePid() {
+    std::lock_guard lock(m_thread_id_mtx);
+    return m_thread_id_map.emplace(0).first;
+  }
+
   long getTscFreq();
 
   void *kalloc(std::size_t size,
@@ -161,6 +171,8 @@ private:
 
   std::atomic<long> m_tsc_freq{0};
 
+  shared_mutex m_thread_id_mtx;
+  OwningIdMap<char, long, 256, 0> m_thread_id_map;
   mutable shared_mutex m_proc_mtx;
   utils::LinkedNode<Process> *m_processes = nullptr;
 

orbis-kernel/include/orbis/pipe.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include "KernelAllocator.hpp"
+#include "file.hpp"
+#include "utils/Rc.hpp"
+
+namespace orbis {
+struct Pipe final : File {
+  kvector<std::byte> data;
+};
+
+Ref<Pipe> createPipe();
+} // namespace orbis

orbis-kernel/include/orbis/thread/ProcessOps.hpp

@@ -70,6 +70,7 @@ struct ProcessOps {
   SysResult (*thr_wake)(Thread *thread, slong id);
   SysResult (*thr_set_name)(Thread *thread, slong id, ptr<const char> name);
 
+  SysResult (*fork)(Thread *thread, slong status);
   SysResult (*exit)(Thread *thread, sint status);
 
   SysResult (*processNeeded)(Thread *thread);

orbis-kernel/include/orbis/utils/SharedCV.hpp

@@ -7,7 +7,7 @@
 namespace orbis {
 inline namespace utils {
 // IPC-ready lightweight condition variable
-class shared_cv {
+class shared_cv final {
   enum : unsigned {
     c_waiter_mask = 0xffff,
     c_signal_mask = 0x7fff0000,