Implement argument_ptr () syscall for handling process arguments

kernel/amd64/proc.c

@@ -58,7 +58,8 @@ struct proc* proc_from_elf (uint8_t* elf_contents) {
   return proc;
 }
 
-struct proc* proc_clone (struct proc* proto, uintptr_t vstack_top, uintptr_t entry) {
+struct proc* proc_clone (struct proc* proto, uintptr_t vstack_top, uintptr_t entry,
+                         uintptr_t argument_ptr) {
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
   spin_lock_ctx_t ctxprt;
 
@@ -88,6 +89,8 @@ struct proc* proc_clone (struct proc* proto, uintptr_t vstack_top, uintptr_t ent
   proc->pdata.regs.cs = GDT_UCODE | 0x03;
   proc->pdata.regs.rip = (uint64_t)entry;
 
+  proc->uvaddr_argument = argument_ptr;
+
   proc_init_tls (proc);
 
   return proc;

kernel/proc/proc.h

@@ -43,6 +43,7 @@ struct proc {
   spin_lock_t lock;
   struct cpu* cpu;
   atomic_int state;
+  uintptr_t uvaddr_argument;
 };
 
 void proc_sched (void);

kernel/sys/proc.h

@@ -6,7 +6,8 @@
 struct proc;
 
 struct proc* proc_from_elf (uint8_t* elf_contents);
-struct proc* proc_clone (struct proc* proto, uintptr_t vstack_top, uintptr_t entry);
+struct proc* proc_clone (struct proc* proto, uintptr_t vstack_top, uintptr_t entry,
+                         uintptr_t argument_ptr);
 void proc_cleanup (struct proc* proc);
 void proc_init_tls (struct proc* proc);
 

kernel/syscall/syscall.c

@@ -78,12 +78,13 @@ DEFINE_SYSCALL (sys_unmap) {
   return SYSRESULT (procgroup_unmap (proc->procgroup, vaddr, pages));
 }
 
-/* int clone (uintptr_t vstack_top, void* entry) */
+/* int clone (uintptr_t vstack_top, void* entry, void* argument_ptr) */
 DEFINE_SYSCALL (sys_clone) {
   uintptr_t vstack_top = a1;
   uintptr_t entry = a2;
+  uintptr_t argument_ptr = a3;
 
-  struct proc* new = proc_clone (proc, vstack_top, entry);
+  struct proc* new = proc_clone (proc, vstack_top, entry, argument_ptr);
 
   if (new == NULL) {
     return SYSRESULT (-ST_OOM_ERROR);
@@ -96,6 +97,9 @@ DEFINE_SYSCALL (sys_clone) {
   return SYSRESULT (pid);
 }
 
+/* void* argument_ptr (void) */
+DEFINE_SYSCALL (sys_argument_ptr) { return proc->uvaddr_argument; }
+
 /* int sched (void) */
 DEFINE_SYSCALL (sys_sched) {
   proc_sched ();
@@ -165,6 +169,7 @@ static syscall_handler_func_t handler_table[] = {
     [SYS_MAP] = &sys_map,
     [SYS_UNMAP] = &sys_unmap,
     [SYS_CLONE] = &sys_clone,
+    [SYS_ARGUMENT_PTR] = &sys_argument_ptr,
     [SYS_SCHED] = &sys_sched,
     [SYS_MUTEX_CREATE] = &sys_mutex_create,
     [SYS_MUTEX_DELETE] = &sys_mutex_delete,