From 1da84c2a2cec89c4d99844ae721561955b35bb1b Mon Sep 17 00:00:00 2001
From: Timon Kruiper <timonkruiper@gmail.com>
Date: Tue, 27 Dec 2022 14:24:50 +0100
Subject: [PATCH] Kernel: Factor out setting Thread entry function

This adds ThreadRegisters::set_entry_function, and also implements it
for aarch64.
---
 Kernel/Arch/aarch64/ThreadRegisters.h |  6 ++++++
 Kernel/Arch/x86_64/ThreadRegisters.h  |  6 ++++++
 Kernel/Process.cpp                    | 10 +---------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/Kernel/Arch/aarch64/ThreadRegisters.h b/Kernel/Arch/aarch64/ThreadRegisters.h
index 540b588693..a3fffaeaa7 100644
--- a/Kernel/Arch/aarch64/ThreadRegisters.h
+++ b/Kernel/Arch/aarch64/ThreadRegisters.h
@@ -25,6 +25,12 @@ struct ThreadRegisters {
     {
         set_sp(kernel_stack_top);
     }
+
+    void set_entry_function(FlatPtr entry_ip, FlatPtr entry_data)
+    {
+        set_ip(entry_ip);
+        x[0] = entry_data;
+    }
 };
 
 }
diff --git a/Kernel/Arch/x86_64/ThreadRegisters.h b/Kernel/Arch/x86_64/ThreadRegisters.h
index 921b2eb610..84004f4abe 100644
--- a/Kernel/Arch/x86_64/ThreadRegisters.h
+++ b/Kernel/Arch/x86_64/ThreadRegisters.h
@@ -73,6 +73,12 @@ struct ThreadRegisters {
             set_sp0(kernel_stack_top);
         }
     }
+
+    void set_entry_function(FlatPtr entry_ip, FlatPtr entry_data)
+    {
+        set_ip(entry_ip);
+        rdi = entry_data; // entry function argument is expected to be in regs.rdi
+    }
 };
 
 }
diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 73e0ff94f3..51bb92217d 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -273,15 +273,7 @@ LockRefPtr<Process> Process::create_kernel_process(LockRefPtr<Thread>& first_thr
         return {};
     auto process = process_or_error.release_value();
 
-    first_thread->regs().set_ip((FlatPtr)entry);
-#if ARCH(X86_64)
-    first_thread->regs().rdi = FlatPtr(entry_data); // entry function argument is expected to be in regs.rdi
-#elif ARCH(AARCH64)
-    (void)entry_data;
-    TODO_AARCH64();
-#else
-#    error Unknown architecture
-#endif
+    first_thread->regs().set_entry_function((FlatPtr)entry, (FlatPtr)entry_data);
 
     if (do_register == RegisterProcess::Yes)
         register_new(*process);