From 66bee86a8b339cd231f9e44dd3c0cce1ca166842 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Sat, 1 Oct 2022 12:28:32 +0200
Subject: [PATCH] Scheduler: add a load_user_task function that directly loads
 a file from the initrd

---
 kernel/include/thread/Scheduler.h |  2 ++
 kernel/src/main.cpp               |  8 +------
 kernel/src/thread/Scheduler.cpp   | 35 +++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/kernel/include/thread/Scheduler.h b/kernel/include/thread/Scheduler.h
index 6359dabe..e6b81a28 100644
--- a/kernel/include/thread/Scheduler.h
+++ b/kernel/include/thread/Scheduler.h
@@ -10,6 +10,8 @@ namespace Scheduler
     void add_kernel_task(void (*task)(void));
     void add_user_task(void* task);
 
+    void load_user_task(const char* filename);
+
     void task_exit(Context* context);
     void task_misbehave(Context* context);
 
diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp
index d804e8d8..38927971 100644
--- a/kernel/src/main.cpp
+++ b/kernel/src/main.cpp
@@ -126,13 +126,7 @@ extern "C" void _start()
         }
     });
 
-    void* elf_start_address = ELFLoader::load_elf_from_initrd("bin/init");
-    if (!elf_start_address) kerrorln("failed to load /bin/init from initrd");
-    else
-    {
-        kinfoln("loaded /bin/init at %lx", (uint64_t)elf_start_address);
-        Scheduler::add_user_task(elf_start_address);
-    }
+    Scheduler::load_user_task("bin/init");
 
     kinfoln("Prepared scheduler tasks");
 
diff --git a/kernel/src/thread/Scheduler.cpp b/kernel/src/thread/Scheduler.cpp
index 2c5801dc..f7e3b71f 100644
--- a/kernel/src/thread/Scheduler.cpp
+++ b/kernel/src/thread/Scheduler.cpp
@@ -10,6 +10,7 @@
 #include "panic/Panic.h"
 #include "std/stdlib.h"
 #include "std/string.h"
+#include "sys/elf/ELFLoader.h"
 #include "thread/PIT.h"
 #include "thread/Task.h"
 
@@ -110,6 +111,40 @@ void Scheduler::add_user_task(void* task)
             new_task->id, new_task->regs.rsp, task_num);
 }
 
+void Scheduler::load_user_task(const char* filename)
+{
+    kinfoln("Loading user task: %s", filename);
+    Task* new_task = new Task;
+    ASSERT(new_task);
+    new_task->id = free_tid++;
+    new_task->regs.rip = (uint64_t)ELFLoader::load_elf_from_initrd(filename);
+    if (!new_task->regs.rip)
+    {
+        kwarnln("Failed to load user task %s", filename);
+        delete new_task;
+        return;
+    }
+    new_task->allocated_stack = (uint64_t)MemoryManager::get_pages(
+        TASK_PAGES_IN_STACK, MAP_READ_WRITE | MAP_USER); // 16 KB is enough for everyone, right?
+    new_task->regs.rsp = new_task->allocated_stack + (4096 * 4) - sizeof(uintptr_t);
+    new_task->regs.cs = 0x18 | 0x03;
+    new_task->regs.ss = 0x20 | 0x03;
+    new_task->regs.ds = 0x20 | 0x03;
+    new_task->regs.rflags = (1 << 21) | (1 << 9); // enable interrupts
+    new_task->task_sleep = 0;
+    new_task->task_time = 0;
+    new_task->cpu_time = 0;
+    end_task->next_task = new_task;
+    new_task->prev_task = end_task;
+    base_task->prev_task = new_task;
+    new_task->next_task = base_task;
+    end_task = new_task;
+    new_task->state = new_task->Running;
+    task_num++;
+    kinfoln("Adding user task: loaded at %lx, tid %ld, stack at %lx, total tasks: %ld", new_task->regs.rip,
+            new_task->id, new_task->regs.rsp, task_num);
+}
+
 void Scheduler::reap_task(Task* task)
 {
     ASSERT(!Interrupts::is_in_handler());