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trying x86_64 support

This commit is contained in:
Marco Cetica 2021-02-03 18:05:18 +01:00
parent b20064b869
commit 634393b141
10 changed files with 192 additions and 19 deletions
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2
Makefile
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@ -1,4 +1,4 @@
LD = i686-elf-ld
LD = x86_64-elf-ld
LFLAGS = -melf_i386 -nostdlib -O2 -T link.ld
all: prepare cpu kernel_code drivers libc userspace mem link iso

2
kernel/Makefile
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@ -1,6 +1,6 @@
OBJS = kernel_main.o
CC = i686-elf-gcc # cross-compiler
CC = x86_64-elf-gcc # cross-compiler
CFLAGS = -m32 -fno-stack-protector -ffreestanding -Wall -Wextra -Werror -g -c

2
kernel/cpu/Makefile
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@ -1,4 +1,4 @@
OBJS = main.asm.o ports.asm.o \
OBJS = main.asm.o main64.asm.o ports.asm.o \
gdt.asm.o idt.asm.o \
interrupts.asm.o header.asm.o

162
kernel/cpu/main.asm
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@ -5,23 +5,169 @@
; Released under GPLv3 ;
; https://github.com/ice-bit/vulcanos ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
GLOBAL kernel_loader
EXTERN kernel_main
EXTERN long_mode_start
[BITS 32] ; Ensure we are in protected mode
section .text
kernel_loader:
mov esp, kernel_stack + KERNEL_STACK_SZ ; Define stack pointer
; Now we need to switch to Long Mode(i.e., 64bit mode)
; to do that, we first need to check if we actually are
; being loaded by a multiboot compliant bootloader. Then,
; we will execute CPUID instruction in order to obtain details
; about out CPU(i.e., if the CPU supports long mode).
call check_multiboot
call check_cpuid
call check_long_mode
; After that, we need to setup paging
call setup_page_tables
call enable_paging
; We also need to load a GDT
lgdt[gdt64.pointer]
jmp gdt64.code_segment:long_mode_start
push eax ; Set multiboot header register
call kernel_main ; Call kernel's main function
check_multiboot:
; To prove that we are being loaded by a multiboot
; bootloader, we can read the EAX register to see if
; it contains the magic number
cmp eax, 0xE85250D6
jne .multiboot_panic
ret
.multiboot_panic:
; We handle this error by showing a special code
mov al, "M"
jmp error ; Call print routine
check_cpuid:
; To check if CPUID is available we need to flip
; ID bit of the flag register, if this is possibile
; then CPUID instruction is available. In order to achieve
pushfd ; Push flag register into the stack
pop eax ; Pop the stack
mov ecx, eax ; Make a copy of the stack
xor eax, 1 << 21 ; Flip ID bit(21th) from the eax register
push eax
popfd ; Restore flag register into the stack
pushfd
pop eax
push ecx
popfd
cmp eax, ecx ; If values are the same, then CPUID is not available
je .cpuid_panic
ret ; Otherwise return
.cpuid_panic:
mov al, "C"
jmp error ; Call print routine
check_long_mode:
; Check if CPU supports extended processor info
mov eax, 0x80000000 ; Store magic number
cpuid ; CPUID instruction takes EAX by default
; CPUID will set EAX a value greater than the magic number
; if the processor supports extended processor info
cmp eax, 0x80000001 ; Magic number + 1
jb .long_mode_panic
; Otherwise we can use extended processor info
; to check if long mode is available
mov eax, 0x80000001
cpuid
; CPUID, with this magic number, will set LM bit(29th)
; if and only if long mode is available
test edx, 1 << 29
jz .long_mode_panic
ret
.long_mode_panic:
mov al, "L"
jmp error ; Call print routine
setup_page_tables:
mov eax, page_table_l3
or eax, 0b11
mov [page_table_l4], eax
mov eax, page_table_l2
or eax, 0b11
mov [page_table_l3], eax
.loop:
jmp .loop ; If the kernel returns, go into an endless loop
; This will prevent the CPU to execure any non-kernel
; instructions.
mov eax, 0x200000 ; 2MiB
mul ecx
or eax, 0b10000011
mov [page_table_l2 + ecx * 8], eax
mov ecx, 0 ; Counter
inc ecx ; Increment counter
cmp ecx, 512 ; Check if whole table is being mapped
jne .loop ; if not, repeat
ret
enable_paging:
; Pass page table location to the cpu
mov eax, page_table_l4
mov cr3, eax
; Enable PAE
mov eax, cr4
or eax, 1 << 5
mov cr4, eax;
; Enable long mode
mov ecx, 0xC0000000
rdmsr
or eax, 1 << 8
wrmsr
; Enable paging
mov eax, cr0
or eax, 1 << 31
mov cr0, eax
ret
error: ; Prints "ERR: X" where X stands ofr the given error code
; This routine will just print the error code in video memory
; Let's understand what those hex codes actually mean:
; 0xB8000 is the begin of the VGA text buffer, each byte will
; contain one character. 0x4F is the color code; it means
; white text on read background. 0x52 is the ASCII code for
; the letter 'R', while 0x45 stands for the letter 'E',
; 0x3A stands for the symbol ':' and 0x20 is just a space.
; Do note that addressing is in little endian ordering and
; that one space is begin overwritten by the ASCII byte.
; previous NEW CONTENT
mov dword [0xB8000], 0x4F524F45 ; [] ER
mov dword [0xB8004], 0x4F3A4F52 ; [ER] R:
mov dword [0xB8008], 0x4F204F20 ; [ERR:] <space>
mov byte [0xB800a], al ; Print the error code
hlt ; Halt the CPU
KERNEL_STACK_SZ equ 4096 ; Stack size(4KiB)
section .bss
align 4
align 4096
page_table_l4:
resb 4096
page_table_l3:
resb 4096
page_table_l2:
resb 4096
kernel_stack:
resb KERNEL_STACK_SZ ; Reserver 4KiB for kernel's stack
resb KERNEL_STACK_SZ ; Reserver 4KiB for kernel's stack
section .rodata
gdt64:
dq 0 ; zero entry
.code_segment: equ $ - gdt64
dq (1 << 4) | (1 << 44) | (1 << 47) | (1 << 53) ; Code segment
; executable, descriptor, present 64bit flags
.pointer:
dw $ - gdt64 - 1
dd gdt64

27
kernel/cpu/main64.asm Normal file
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@ -0,0 +1,27 @@
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; vulcanOS Kernel ;
; Developed by Marco 'icebit' Cetica ;
; (c) 2019-2021 ;
; Released under GPLv3 ;
; https://github.com/ice-bit/vulcanos ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
GLOBAL long_mode_start
GLOBAL kernel_loader
EXTERN kernel_main
section .text
[BITS 64] ; Ensure we are in long mode
long_mode_start:
xor ax, ax
mov ss, ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
; Call the kernel's main method
call kernel_main ; Call kernel's main function
.loop:
jmp .loop ; If the kernel returns, go into an endless loop
; This will prevent the CPU to execure any non-kernel
; instructions.

2
kernel/drivers/Makefile
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@ -1,7 +1,7 @@
OBJS = tty.o gdt.o idt.o isr.o timer.o keyboard.o \
fs.o cpuid.o
CC = i686-elf-gcc # cross-compiler
CC = x86_64-elf-gcc # cross-compiler
CFLAGS = -m32 -fno-stack-protector -DDEFAULT_USER=root -DDEFAULT_HOSTNAME=vulcan -ffreestanding -Wall -Wextra -Werror -g -c

8
kernel/kernel_main.c
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@ -6,7 +6,7 @@
* https://github.com/ice-bit/vulcanos *
*****************************************/
#include "drivers/tty.h"
#include "drivers/gdt.h"
//#include "drivers/gdt.h"
#include "drivers/idt.h"
#include "drivers/timer.h"
#include "drivers/keyboard.h"
@ -41,9 +41,9 @@ void kernel_main(unsigned long magic, uint32_t addr) {
printf("Loading kernel, wait please...");
gdt_setup(); // Setup Global Descriptor Table
PRTOK
printf(" - Loaded GDT");
// gdt_setup(); // Setup Global Descriptor Table
// PRTOK
// printf(" - Loaded GDT");
idt_setup(); // Setup Interrupt Descriptor Table
PRTOK

2
kernel/libc/Makefile
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@ -1,7 +1,7 @@
OBJS = stdio.o string.o panic.o time.o
VER := $(shell git rev-parse --short HEAD)
CC = i686-elf-gcc # cross-compiler
CC = x86_64-elf-gcc # cross-compiler
CFLAGS = -DVULCAN_VERSION=$(VER) -m32 -fno-stack-protector -ffreestanding -Wall -Wextra -Werror -g -c

2
kernel/mem/Makefile
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@ -1,6 +1,6 @@
OBJS = paging.o kheap.o ordered_array.o
CC = i686-elf-gcc # cross-compiler
CC = x86_64-elf-gcc # cross-compiler
CFLAGS = -m32 -fno-stack-protector -ffreestanding -Wall -Wextra -Werror -g -c
all:${OBJS}

2
kernel/userspace/Makefile
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@ -1,7 +1,7 @@
OBJS = shell.o fetch.o
VER := $(shell git rev-parse --short HEAD)
CC = i686-elf-gcc # cross-compiler
CC = x86_64-elf-gcc # cross-compiler
CFLAGS = -DDEFAULT_USER=root -DDEFAULT_HOSTNAME=vulcan -DVULCAN_VERSION=$(VER) -m32 -fno-stack-protector -ffreestanding -Wall -Wextra -Werror -g -c
all:${OBJS}