Implement proc_spawn_thread syscall, fix proc_resume and proc_suspend

kernel/proc/proc.h

@@ -25,6 +25,8 @@
 
 #define PROC_RESOURCES_MAX 1024
 
+#define PROC_USTK_PREALLOC (1 << 0)
+
 struct cpu;
 
 struct proc_mapping {
@@ -35,6 +37,11 @@ struct proc_mapping {
   size_t size;
 };
 
+struct proc_sys_rids {
+  atomic_int refs;
+  atomic_int counter;
+};
+
 struct proc {
   int pid;
   struct rb_node_link proc_tree_link;
@@ -44,11 +51,13 @@ struct proc {
 
   struct list_node_link* mappings; /* pd.lock implicitly protects this field */
   struct proc_platformdata pdata;
+  uint32_t flags;
   struct pd* pd;
   spin_lock_t lock;
   struct cpu* cpu;
   atomic_int state;
   struct rb_node_link* resource_tree;
+  struct proc_sys_rids* sys_rids;
   struct proc_suspension_q* suspension_q;
 };
 
@@ -60,6 +69,7 @@ bool proc_map (struct proc* proc, uintptr_t start_paddr, uintptr_t start_vaddr,
                uint32_t flags);
 bool proc_unmap (struct proc* proc, uintptr_t start_vaddr, size_t pages);
 struct elf_aux proc_load_segments (struct proc* proc, uint8_t* elf);
+void proc_register (struct proc* proc, struct cpu* cpu);
 void proc_init (void);
 
 #endif // _KERNEL_PROC_PROC_H