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Author SHA1 Message Date
fafe05c251 feat(ci): update ci with new toolchain
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Signed-off-by: Julien CLEMENT <julien.clement@epita.fr>
2021-11-29 15:00:47 +01:00
30c103a6b3 feat(grub): add multi-boot support and long mode swap
Signed-off-by: Julien CLEMENT <julien.clement@epita.fr>
2021-11-29 14:59:34 +01:00
12 changed files with 281 additions and 19 deletions

@ -4,6 +4,3 @@ target = "x86_64-julios.json"
[unstable] [unstable]
build-std-features = ["compiler-builtins-mem"] build-std-features = ["compiler-builtins-mem"]
build-std = ["core", "compiler_builtins"] build-std = ["core", "compiler_builtins"]
[target.'cfg(target_os = "none")']
runner = "bootimage runner"

@ -5,10 +5,8 @@ steps:
- name: build - name: build
image: rustlang/rust:nightly image: rustlang/rust:nightly
commands: commands:
- cargo install bootimage
- rustup component add llvm-tools-preview
- rustup component add rust-src - rustup component add rust-src
- cargo bootimage - make
- name: release - name: release
image: plugins/gitea-release image: plugins/gitea-release
@ -16,6 +14,6 @@ steps:
api_key: api_key:
from_secret: api_key from_secret: api_key
base_url: http://gitea_web_1:3000 base_url: http://gitea_web_1:3000
files: target/x86_64-julios/debug/bootimage-julios.bin files: julios.iso
when: when:
event: tag event: tag

4
.gitignore vendored

@ -1 +1,5 @@
/target /target
iso
*.iso
*.o
julios

9
Cargo.lock generated

@ -2,15 +2,6 @@
# It is not intended for manual editing. # It is not intended for manual editing.
version = 3 version = 3
[[package]]
name = "bootloader"
version = "0.9.19"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b7c452074efc3c0bfb241fb7bc87df04741c7c85e926f6a07c05f8fbd6008240"
[[package]] [[package]]
name = "julios" name = "julios"
version = "0.1.0" version = "0.1.0"
dependencies = [
"bootloader",
]

@ -5,5 +5,5 @@ edition = "2018"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies] [lib]
bootloader = "0.9.8" crate-type = ["staticlib"]

39
Makefile Normal file

@ -0,0 +1,39 @@
KERNEL = julios
ISO = julios.iso
INSTALL_ROOT = iso
ABS_INSTALL = $(abspath $(INSTALL_ROOT))
LINKER_SCRIPT = src/linker.ld
BOOT_OBJS = src/multiboot.o src/boot.o
LIB_JULIOS = target/x86_64-julios/debug/libjulios.a
GRUB_CFG = grub/grub.cfg
all: $(ISO)
$(ISO): install
./tools/create-iso.sh $@ $(INSTALL_ROOT)
install: $(KERNEL) $(GRUB_CFG)
mkdir -p $(ABS_INSTALL)
mkdir -p $(ABS_INSTALL)/boot/grub
cp $(KERNEL) $(ABS_INSTALL)/boot
cp grub/grub.cfg $(ABS_INSTALL)/boot/grub
$(KERNEL): $(LIB_JULIOS) $(LINKER_SCRIPT) $(BOOT_OBJS)
ld -n -T $(LINKER_SCRIPT) -o $(KERNEL) $(BOOT_OBJS) $(LIB_JULIOS)
$(LIB_JULIOS):
cargo build
%.o: %.asm
nasm -f elf64 $^ -o $@
clean:
$(RM) $(BOOT_OBJS)
$(RM) $(KERNEL)
$(RM) julios.iso
$(RM) -r iso
.PHONY: $(INSTALL_ROOT) install clean all

4
grub/grub.cfg Normal file

@ -0,0 +1,4 @@
menuentry "julios" {
multiboot2 /boot/julios
boot
}

190
src/boot.asm Normal file

@ -0,0 +1,190 @@
section .rodata
gdt64:
dq 0
.code: equ $ - gdt64
dq (1<<43) | (1<<44) | (1<<47) | (1<<53)
.pointer:
dw $ - gdt64 - 1
dq gdt64
global _start
section .text
bits 32
_start:
mov esp, stack_top
call check_multiboot
call check_cpuid
call check_long_mode
call set_up_page_tables
call enable_paging
lgdt [gdt64.pointer]
jmp gdt64.code:long_mode_start
set_up_page_tables:
; map first P4 entry to P3 table
mov eax, p3_table
or eax, 0b11 ; present + writable
mov [p4_table], eax
; map first P3 entry to P2 table
mov eax, p2_table
or eax, 0b11 ; present + writable
mov [p3_table], eax
; map each P2 entry to a huge 2MiB page
mov ecx, 0 ; counter variable
.map_p2_table:
; map ecx-th P2 entry to a huge page that starts at address 2MiB*ecx
mov eax, 0x200000 ; 2MiB
mul ecx ; start address of ecx-th page
or eax, 0b10000011 ; present + writable + huge
mov [p2_table + ecx * 8], eax ; map ecx-th entry
inc ecx ; increase counter
cmp ecx, 512 ; if counter == 512, the whole P2 table is mapped
jne .map_p2_table ; else map the next entry
ret
enable_paging:
; load P4 to cr3 register (cpu uses this to access the P4 table)
mov eax, p4_table
mov cr3, eax
; enable PAE-flag in cr4 (Physical Address Extension)
mov eax, cr4
or eax, 1 << 5
mov cr4, eax
; set the long mode bit in the EFER MSR (model specific register)
mov ecx, 0xC0000080
rdmsr
or eax, 1 << 8
wrmsr
; enable paging in the cr0 register
mov eax, cr0
or eax, 1 << 31
mov cr0, eax
ret
; Prints `ERR: ` and the given error code to screen and hangs.
; parameter: error code (in ascii) in al
error:
mov dword [0xb8000], 0x4f524f45
mov dword [0xb8004], 0x4f3a4f52
mov dword [0xb8008], 0x4f204f20
mov byte [0xb800a], al
hlt
check_multiboot:
cmp eax, 0x36d76289
jne .no_multiboot
ret
.no_multiboot:
mov al, "0"
jmp error
check_cpuid:
; Check if CPUID is supported by attempting to flip the ID bit (bit 21)
; in the FLAGS register. If we can flip it, CPUID is available.
; Copy FLAGS in to EAX via stack
pushfd
pop eax
; Copy to ECX as well for comparing later on
mov ecx, eax
; Flip the ID bit
xor eax, 1 << 21
; Copy EAX to FLAGS via the stack
push eax
popfd
; Copy FLAGS back to EAX (with the flipped bit if CPUID is supported)
pushfd
pop eax
; Restore FLAGS from the old version stored in ECX (i.e. flipping the
; ID bit back if it was ever flipped).
push ecx
popfd
; Compare EAX and ECX. If they are equal then that means the bit
; wasn't flipped, and CPUID isn't supported.
cmp eax, ecx
je .no_cpuid
ret
.no_cpuid:
mov al, "1"
jmp error
check_long_mode:
; test if extended processor info in available
mov eax, 0x80000000 ; implicit argument for cpuid
cpuid ; get highest supported argument
cmp eax, 0x80000001 ; it needs to be at least 0x80000001
jb .no_long_mode ; if it's less, the CPU is too old for long mode
; use extended info to test if long mode is available
mov eax, 0x80000001 ; argument for extended processor info
cpuid ; returns various feature bits in ecx and edx
test edx, 1 << 29 ; test if the LM-bit is set in the D-register
jz .no_long_mode ; If it's not set, there is no long mode
ret
.no_long_mode:
mov al, "2"
jmp error
section .bss
align 4096
p4_table:
resb 4096
p3_table:
resb 4096
p2_table:
resb 4096
stack_bottom:
resb 64
stack_top:
global long_mode_start
section .text
bits 64
long_mode_start:
; load 0 into all data segment registers
mov ax, 0
mov ss, ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
extern julios_main
call julios_main
mov rax, 0x2f592f412f4b2f4f
mov qword [0xb8000], rax
.loop:
jmp .loop

@ -10,7 +10,7 @@ fn panic(_info: &core::panic::PanicInfo) -> !
static HELLO: &[u8] = b"Welcome to the JuliOS"; static HELLO: &[u8] = b"Welcome to the JuliOS";
#[no_mangle] #[no_mangle]
pub extern "C" fn _start() -> ! pub extern "C" fn julios_main() -> !
{ {
let vga_buffer: *mut u8 = 0xb8000 as *mut u8; let vga_buffer: *mut u8 = 0xb8000 as *mut u8;

16
src/linker.ld Normal file

@ -0,0 +1,16 @@
ENTRY(_start)
SECTIONS {
. = 1M;
.boot :
{
/* ensure that the multiboot header is at the beginning */
*(.multiboot_header)
}
.text :
{
*(.text)
}
}

15
src/multiboot.asm Normal file

@ -0,0 +1,15 @@
section .multiboot_header
header_start:
dd 0xe85250d6 ; magic number (multiboot 2)
dd 0 ; architecture 0 (protected mode i386)
dd header_end - header_start ; header length
; checksum
dd 0x100000000 - (0xe85250d6 + 0 + (header_end - header_start))
; insert optional multiboot tags here
; required end tag
dw 0 ; type
dw 0 ; flags
dd 8 ; size
header_end:

8
tools/create-iso.sh Executable file

@ -0,0 +1,8 @@
#!/bin/sh
iso_filename=$1
base_dir=$2
unset MFLAGS MAKEFLAGS
grub-mkrescue -o $iso_filename $base_dir