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Kernel/x86: Bake the Prekernel and the Kernel into one image

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The new baked image is a Prekernel and a Kernel baked together now, so
essentially we no longer need to pass the Prekernel as -kernel and the
actual kernel image as -initrd to QEMU, leaving the option to pass an
actual initrd or initramfs module later on with multiboot.
This commit is contained in:
Liav A
2023-03-24 20:31:53 +03:00
committed by Tim Schumacher
parent 90a46cdc98
commit d068af89d5
10 changed files with 83 additions and 44 deletions
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34
Kernel/Prekernel/init.cpp
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@@ -27,6 +27,9 @@ extern "C" [[noreturn]] void __stack_chk_fail();
extern "C" u8 start_of_prekernel_image[];
extern "C" u8 end_of_prekernel_image[];
extern "C" u8 _binary_Kernel_standalone_start[];
extern "C" u8 end_of_prekernel_image_after_kernel_image[];
extern "C" u8 gdt64ptr[];
extern "C" u16 code64_sel;
extern "C" u64 boot_pml4t[512];
@@ -92,12 +95,20 @@ static void memmove_virt(void* dest_virt, FlatPtr dest_phys, void* src, size_t n
extern "C" [[noreturn]] void init()
{
if (multiboot_info_ptr->mods_count < 1)
halt();
u32 initrd_module_start = 0;
u32 initrd_module_end = 0;
if (multiboot_info_ptr->mods_count > 0) {
// We only consider the first specified multiboot module, and ignore
// the rest of the modules.
multiboot_module_entry_t* initrd_module = (multiboot_module_entry_t*)(FlatPtr)multiboot_info_ptr->mods_addr;
if (initrd_module->start > initrd_module->end)
halt();
multiboot_module_entry_t* kernel_module = (multiboot_module_entry_t*)(FlatPtr)multiboot_info_ptr->mods_addr;
initrd_module_start = initrd_module->start;
initrd_module_end = initrd_module->end;
}
u8* kernel_image = (u8*)(FlatPtr)kernel_module->start;
u8* kernel_image = _binary_Kernel_standalone_start;
// copy the ELF header and program headers because we might end up overwriting them
Elf_Ehdr kernel_elf_header = *(Elf_Ehdr*)kernel_image;
Elf_Phdr kernel_program_headers[16];
@@ -105,8 +116,8 @@ extern "C" [[noreturn]] void init()
halt();
__builtin_memcpy(kernel_program_headers, kernel_image + kernel_elf_header.e_phoff, sizeof(Elf_Phdr) * kernel_elf_header.e_phnum);
FlatPtr kernel_physical_base = 0x200000;
FlatPtr default_kernel_load_base = KERNEL_MAPPING_BASE + 0x200000;
FlatPtr kernel_physical_base = (FlatPtr)kernel_image;
FlatPtr default_kernel_load_base = KERNEL_MAPPING_BASE + kernel_physical_base;
FlatPtr kernel_load_base = default_kernel_load_base;
@@ -179,9 +190,6 @@ extern "C" [[noreturn]] void init()
// overwriting mbi end as to avoid to check whether it's mapped after reloading page tables.
BootInfo info {};
multiboot_info_ptr->mods_count--;
multiboot_info_ptr->mods_addr += sizeof(multiboot_module_entry_t);
auto adjust_by_mapping_base = [kernel_mapping_base](auto ptr) {
return (decltype(ptr))((FlatPtr)ptr + kernel_mapping_base);
};
@@ -189,8 +197,12 @@ extern "C" [[noreturn]] void init()
info.multiboot_flags = multiboot_info_ptr->flags;
info.multiboot_memory_map = adjust_by_mapping_base((FlatPtr)multiboot_info_ptr->mmap_addr);
info.multiboot_memory_map_count = multiboot_info_ptr->mmap_length / sizeof(multiboot_memory_map_t);
info.multiboot_modules = adjust_by_mapping_base((FlatPtr)multiboot_info_ptr->mods_addr);
info.multiboot_modules_count = multiboot_info_ptr->mods_count;
if (initrd_module_start != 0 && initrd_module_end != 0) {
info.multiboot_module_physical_ptr = initrd_module_start;
info.multiboot_module_length = initrd_module_end - initrd_module_start;
}
if ((multiboot_info_ptr->flags & MULTIBOOT_INFO_FRAMEBUFFER_INFO) != 0) {
info.multiboot_framebuffer_addr = multiboot_info_ptr->framebuffer_addr;
info.multiboot_framebuffer_pitch = multiboot_info_ptr->framebuffer_pitch;