higher half kernel
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parent
bd20049519
commit
b2b1fc59b7
2
bochsrc
2
bochsrc
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@ -2,4 +2,4 @@ ata0-slave: type=cdrom, path=./build/Hazel.iso, status=inserted
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magic_break: enabled=1
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boot: cdrom
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display_library: sdl2
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display_library: x
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@ -4,7 +4,7 @@
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%define VID 1<<2
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%define FLAGS (ALIGN | MMAP | VID)
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section .multiboot
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section .multiboot.data
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dd MAGIC
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dd FLAGS
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dd -(MAGIC + FLAGS)
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@ -19,7 +19,7 @@ dd 80 ; width
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dd 25 ; height
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dd 0 ; depth
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section .text
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section .multiboot.text
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global _start
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_start:
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cli
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@ -28,9 +28,40 @@ _start:
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cmp eax, 0x2BADB002
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jne halt
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; Setup table
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; Identity page 0-4 mib
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mov eax, 0
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mov edx, 0
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.fill_table:
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mov ecx, edx
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or ecx, 3
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mov [boot_page_tab-0xC0000000+eax*4], ecx
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add edx, 0x1000
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inc eax
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cmp eax, 1024
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jne .fill_table
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mov ecx, boot_page_tab
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sub ecx, 0xC0000000
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or ecx, 3
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mov [boot_page_dir-0xC0000000], ecx
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mov [boot_page_dir-0xC0000000+768*4], ecx
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; Enable paging
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mov eax, boot_page_dir
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sub eax, 0xC0000000
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mov cr3, eax
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mov eax, cr0
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or eax, (1<<31)
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mov cr0, eax
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jmp higher_half
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section .text
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higher_half:
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; Load GDT
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lgdt [gdtp]
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; Offset to kernel data descriptor
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; Offset to kernel data descriptor
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mov ax, 0x10
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mov es, ax
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mov ds, ax
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@ -52,7 +83,6 @@ halt:
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global pit_isr
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pit_isr:
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cli
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extern pit_handler
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call pit_handler
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iret
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@ -187,6 +217,11 @@ gdtp:
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dw gdt_end - gdt - 1
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dd gdt
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align 0x1000
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boot_page_dir: times 1024 dd 0
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align 0x1000
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boot_page_tab: times 1024 dd 0
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section .bss
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align 16
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stack_top:
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@ -37,9 +37,6 @@ typedef struct {
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uint32_t cr3;
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} task_t;
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__attribute__((aligned(4096))) uint32_t page_dir[1024];
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__attribute__((aligned(4096))) uint32_t page_tab[1024];
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void kernel(multiboot_info_t *info) {
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if (!CHECK_FLAG(info->flags, 3)) goto halt; // Modules
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if (!CHECK_FLAG(info->flags, 6)) goto halt; // Memory map
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@ -93,31 +90,11 @@ void kernel(multiboot_info_t *info) {
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#define PAGE_TAB_INDEX(x) (((x) >> 12) & 0x3FF)
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#define PAGE_OFFSET(x) ((x) & 0xFFF)
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for (int i = 0; i < 1024; i++) {
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page_tab[i] = (i * 0x1000) | PAGE_PRESENT | PAGE_RW | PAGE_USER;
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}
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for (int i = 0; i < 1024; i++) {
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page_dir[i] = ((uint32_t)page_tab) | PAGE_PRESENT | PAGE_RW | PAGE_USER;
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}
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//enable_paging(page_dir);
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asm volatile("mov %0, %%cr3" :: "r" (page_dir));
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asm volatile(
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"mov %%cr0, %%eax;"
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"or $0x80000000, %%eax;"
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"mov %%eax, %%cr0;"
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:
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:
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: "%eax"
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);
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uint32_t stack = (uint32_t)mmap_find_first_free_block();
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multi_mod_t *init = (multi_mod_t *)info->moduleaddress;
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LOG("Switching to ring 3... EIP: 0x%08X ESP: 0x%08X\n", init->mod_start, stack+0x1000);
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jmp_user_mode(stack+0x1000, init->mod_start);
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//jmp_user_mode(stack+0x1000, init->mod_start);
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halt:
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for (;;) {}
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@ -1,52 +1,36 @@
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/* The bootloader will look at this image and start execution at the symbol
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designated as the entry point. */
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ENTRY(_start)
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/* Tell where the various sections of the object files will be put in the final
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kernel image. */
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SECTIONS
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{
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/* It used to be universally recommended to use 1M as a start offset,
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as it was effectively guaranteed to be available under BIOS systems.
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However, UEFI has made things more complicated, and experimental data
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strongly suggests that 2M is a safer place to load. In 2016, a new
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feature was introduced to the multiboot2 spec to inform bootloaders
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that a kernel can be loaded anywhere within a range of addresses and
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will be able to relocate itself to run from such a loader-selected
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address, in order to give the loader freedom in selecting a span of
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memory which is verified to be available by the firmware, in order to
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work around this issue. This does not use that feature, so 2M was
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chosen as a safer option than the traditional 1M. */
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. = 1M;
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/* First put the multiboot header, as it is required to be put very early
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in the image or the bootloader won't recognize the file format.
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Next we'll put the .text section. */
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.text BLOCK(4K) : ALIGN(4K)
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{
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*(.multiboot)
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*(.text)
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_kernel_start = .;
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.multiboot.data : {
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*(.multiboot.data)
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}
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.multiboot.text : {
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*(.multiboot.text)
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}
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/* Read-only data. */
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.rodata BLOCK(4K) : ALIGN(4K)
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. += 0xC0000000;
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.text ALIGN (4K) : AT (ADDR (.text) - 0xC0000000)
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{
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*(.text)
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}
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.rodata ALIGN (4K) : AT (ADDR (.rodata) - 0xC0000000)
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{
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*(.rodata)
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}
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/* Read-write data (initialized) */
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.data BLOCK(4K) : ALIGN(4K)
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.data ALIGN (4K) : AT (ADDR (.data) - 0xC0000000)
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{
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*(.data)
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}
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/* Read-write data (uninitialized) and stack */
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.bss BLOCK(4K) : ALIGN(4K)
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.bss ALIGN (4K) : AT (ADDR (.bss) - 0xC0000000)
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{
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*(COMMON)
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*(.bss)
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*(.bootstrap_stack)
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}
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/* The compiler may produce other sections, by default it will put them in
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a segment with the same name. Simply add stuff here as needed. */
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_kernel_end = .;
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}
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