Kernel: Move boot info declarations to a header file

Instead of manually redeclaring those variables in various files this
now adds a header file for them.

Kernel/BootInfo.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2021, Gunnar Beutner <gbeutner@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/VirtualAddress.h>
+
+extern "C" u8 const* start_of_prekernel_image;
+extern "C" u8 const* end_of_prekernel_image;
+extern "C" __attribute__((section(".boot_bss"))) FlatPtr kernel_base;
+#if ARCH(X86_64)
+extern "C" u32 gdt64ptr;
+extern "C" u16 code64_sel;
+extern "C" FlatPtr boot_pml4t;
+#endif
+extern "C" FlatPtr boot_pdpt;
+extern "C" FlatPtr boot_pd0;
+extern "C" FlatPtr boot_pd_kernel;
+extern "C" FlatPtr boot_pd_kernel_pt1023;
+extern "C" const char* kernel_cmdline;

Kernel/Prekernel/BootInfo.h

@@ -1,30 +0,0 @@
-/*
- * Copyright (c) 2021, Gunnar Beutner <gbeutner@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include <AK/Platform.h>
-#include <Kernel/Multiboot.h>
-
-namespace Kernel {
-
-struct [[gnu::packed]] BootInfo {
-    u8 const* start_of_prekernel_image;
-    u8 const* end_of_prekernel_image;
-    FlatPtr kernel_base;
-    multiboot_info* multiboot_info_ptr;
-#if ARCH(X86_64)
-    u32 gdt64ptr;
-    u16 code64_sel;
-    FlatPtr boot_pml4t;
-#endif
-    FlatPtr boot_pdpt;
-    FlatPtr boot_pd0;
-    FlatPtr boot_pd_kernel;
-    FlatPtr boot_pd_kernel_pt1023;
-    char const* kernel_cmdline;
-};
-}

Kernel/Prekernel/Prekernel.h

@@ -6,4 +6,30 @@
 
 #pragma once
 
+#ifdef __cplusplus
+#    include <Kernel/Multiboot.h>
+#endif
+
 #define MAX_KERNEL_SIZE 0x3000000
+
+#ifdef __cplusplus
+namespace Kernel {
+
+struct [[gnu::packed]] BootInfo {
+    u8 const* start_of_prekernel_image;
+    u8 const* end_of_prekernel_image;
+    FlatPtr kernel_base;
+    multiboot_info* multiboot_info_ptr;
+#    if ARCH(X86_64)
+    u32 gdt64ptr;
+    u16 code64_sel;
+    FlatPtr boot_pml4t;
+#    endif
+    FlatPtr boot_pdpt;
+    FlatPtr boot_pd0;
+    FlatPtr boot_pd_kernel;
+    FlatPtr boot_pd_kernel_pt1023;
+    char const* kernel_cmdline;
+};
+}
+#endif

Kernel/Prekernel/init.cpp

@@ -8,7 +8,6 @@
 
 #include <AK/Types.h>
 #include <Kernel/Multiboot.h>
-#include <Kernel/Prekernel/BootInfo.h>
 #include <Kernel/Prekernel/Prekernel.h>
 #include <Kernel/VirtualAddress.h>
 #include <LibC/elf.h>

Kernel/Sections.h

@@ -9,15 +9,12 @@
 #include <AK/Platform.h>
 #ifdef __cplusplus
 #    include <AK/Types.h>
+#    include <Kernel/BootInfo.h>
 #endif
 
 #define READONLY_AFTER_INIT __attribute__((section(".ro_after_init")))
 #define UNMAP_AFTER_INIT NEVER_INLINE __attribute__((section(".unmap_after_init")))
 
-#ifdef __cplusplus
-extern "C" FlatPtr kernel_base;
-#endif
-
 #define KERNEL_PD_END (kernel_base + 0x31000000)
 #define KERNEL_PT1024_BASE (kernel_base + 0x3FE00000)
 #define KERNEL_QUICKMAP_PT (KERNEL_PT1024_BASE + 0x6000)

Kernel/VM/MemoryManager.cpp

@@ -7,6 +7,7 @@
 #include <AK/Assertions.h>
 #include <AK/Memory.h>
 #include <AK/StringView.h>
+#include <Kernel/BootInfo.h>
 #include <Kernel/CMOS.h>
 #include <Kernel/FileSystem/Inode.h>
 #include <Kernel/Heap/kmalloc.h>
@@ -22,8 +23,6 @@
 #include <Kernel/VM/PhysicalRegion.h>
 #include <Kernel/VM/SharedInodeVMObject.h>
 
-extern u8* start_of_prekernel_image;
-extern u8* end_of_prekernel_image;
 extern u8* start_of_kernel_image;
 extern u8* end_of_kernel_image;
 extern FlatPtr start_of_kernel_text;
@@ -36,9 +35,6 @@ extern FlatPtr end_of_unmap_after_init;
 extern FlatPtr start_of_kernel_ksyms;
 extern FlatPtr end_of_kernel_ksyms;
 
-extern "C" void* boot_pd_kernel;
-extern "C" void* boot_pd_kernel_pt1023;
-
 extern multiboot_module_entry_t multiboot_copy_boot_modules_array[16];
 extern size_t multiboot_copy_boot_modules_count;
 

Kernel/VM/PageDirectory.cpp

@@ -31,14 +31,6 @@ RefPtr<PageDirectory> PageDirectory::find_by_cr3(FlatPtr cr3)
     return cr3_map().get(cr3).value_or({});
 }
 
-extern "C" FlatPtr kernel_base;
-#if ARCH(X86_64)
-extern "C" void* boot_pml4t;
-#endif
-extern "C" void* boot_pdpt;
-extern "C" void* boot_pd0;
-extern "C" void* boot_pd_kernel;
-
 UNMAP_AFTER_INIT PageDirectory::PageDirectory()
 {
     // make sure this starts in a new page directory to make MemoryManager::initialize_physical_pages() happy

Kernel/init.cpp

@@ -10,6 +10,7 @@
 #include <Kernel/ACPI/MultiProcessorParser.h>
 #include <Kernel/Arch/PC/BIOS.h>
 #include <Kernel/Arch/x86/Processor.h>
+#include <Kernel/BootInfo.h>
 #include <Kernel/Bus/PCI/Access.h>
 #include <Kernel/Bus/PCI/Initializer.h>
 #include <Kernel/Bus/USB/UHCIController.h>
@@ -39,7 +40,7 @@
 #include <Kernel/Net/NetworkTask.h>
 #include <Kernel/Net/NetworkingManagement.h>
 #include <Kernel/Panic.h>
-#include <Kernel/Prekernel/BootInfo.h>
+#include <Kernel/Prekernel/Prekernel.h>
 #include <Kernel/Process.h>
 #include <Kernel/ProcessExposed.h>
 #include <Kernel/RTC.h>
@@ -110,8 +111,6 @@ u8 const* start_of_prekernel_image;
 u8 const* end_of_prekernel_image;
 __attribute__((section(".boot_bss"))) FlatPtr kernel_base;
 #if ARCH(X86_64)
-extern "C" u32 gdt64ptr;
-extern "C" u16 code64_sel;
 FlatPtr boot_pml4t;
 #endif
 FlatPtr boot_pdpt;