Add memory initialization

kernel/BUILD.bazel

@@ -4,8 +4,10 @@ nasm_cc_binary(
     name = "kernel",
     srcs = [
         "include/Kernel.h",
+        "include/Kernel/Bootstrap.h",
         "include/Kernel/X64/GDT.h",
         "include/Kernel/X64/IDT.h",
+        "source/Bootstrap/Common.c",
         "source/Bootstrap/Limine.c",
         "source/Main.c",
         "source/X64/GDT.c",
@@ -84,6 +86,7 @@ nasm_cc_binary(
         "//visibility:public",
     ],
     deps = [
+        "//lib/compat_c",
         "//lib/runtime",
         "@limine",
     ],

kernel/include/Kernel.h

@@ -5,6 +5,8 @@
 
 #include <RuntimeLib.h>
 
+#include "Kernel/Bootstrap.h"
+
 #include "Kernel/X64/GDT.h"
 #include "Kernel/X64/IDT.h"
 

kernel/include/Kernel/Bootstrap.h

@@ -0,0 +1,10 @@
+#pragma once
+
+#ifndef __KERNEL_H__
+    #error "This file should be included from Kernel.h"
+#endif
+
+VOID
+CommonStartupRoutine(
+    PAGE_ALLOCATOR *BumpAllocator
+    );

kernel/source/Bootstrap/Common.c

@@ -0,0 +1,17 @@
+#include <RuntimeLib.h>
+#include <Kernel.h>
+
+PAGE_ALLOCATOR* g_PageAllocator;
+
+VOID
+CommonStartupRoutine(
+    PAGE_ALLOCATOR *BumpAllocator
+    )
+{
+    // TODO: g_PageAllocator = BuddyAllocatorInit (BumpAllocator);
+    g_PageAllocator = BumpAllocator;
+
+    KernelMain ();
+}
+
+// TODO: General purpose memory allocation functions using slab allocator

kernel/source/Bootstrap/Limine.c

@@ -1,15 +1,57 @@
 #include <RuntimeLib.h>
 #include <Kernel.h>
 
+#include "limine.h"
+
+BUMP_ALLOCATOR g_BumpAllocator;
+
+//
+// Set the base revision to 1, this is recommended as this is the latest
+// base revision described by the Limine boot protocol specification.
+// See specification for further info.
+//
+
+LIMINE_BASE_REVISION(1);
+
+//
+// Memory map
+//
+
+struct limine_memmap_request g_LimineMemmap = {
+    .id = LIMINE_MEMMAP_REQUEST,
+    .revision = 0
+};
+
 VOID
 StartupRoutine (
     VOID
     )
 {
-    // TODO: pass the correct arguments
-    // TODO: init architecture
+    UINTN BumperIdx;
+
     GDTInit ();
     IDTInit ();
 
-    KernelMain ();
+    BumperIdx = 0;
+    for (UINT64 i = 0; i < g_LimineMemmap.response->entry_count; i++)
+    {
+        if (g_LimineMemmap.response->entries[i]->type == LIMINE_MEMMAP_USABLE)
+        {
+            BUMPER *bumper = &g_BumpAllocator.bumpers[BumperIdx++];
+            bumper->heap_start = g_LimineMemmap.response->entries[i]->base;
+            bumper->heap_end = g_LimineMemmap.response->entries[i]->base + g_LimineMemmap.response->entries[i]->length;
+            bumper->next = bumper->heap_start;
+
+            if (BumperIdx == MAXIMUM_BUMPERS)
+            {
+                // Memory is too fragmented, we can't continue. This is fine but we'll use
+                // some usable memory.
+
+                // TODO: log warning
+                break;
+            }
+        }
+    }
+
+    CommonStartupRoutine ((PAGE_ALLOCATOR *)&g_BumpAllocator);
 }