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Bruh- modifying the screen buffer without a lock omg

This commit is contained in:
elfein 2021-11-22 01:51:11 -08:00
parent 681dc11b1b
commit f749c89cfc
4 changed files with 155 additions and 51 deletions

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@ -33,7 +33,7 @@ psp = "0.1.5"
[target.'cfg(target_arch = "x86_64")'.dependencies] [target.'cfg(target_arch = "x86_64")'.dependencies]
volatile = "0.2.6" volatile = "0.2.6"
bootloader = "0.9.8" bootloader = {version = "0.9.8", features = ["map_physical_memory"]}
cpuio = { git = "https://github.com/anyusernameworks/cpuio.git" } cpuio = { git = "https://github.com/anyusernameworks/cpuio.git" }
x86_64 = "*" x86_64 = "*"
uart_16550 = "0.2.0" uart_16550 = "0.2.0"

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@ -0,0 +1,81 @@
use x86_64::{
structures::paging::{
FrameAllocator, Mapper, OffsetPageTable, Page, PageTable, PhysFrame, Size4KiB,
},
PhysAddr, VirtAddr,
};
pub unsafe fn init(physical_memory_offset: VirtAddr) -> OffsetPageTable<'static> {
let level_4_table = active_level_4_table(physical_memory_offset);
OffsetPageTable::new(level_4_table, physical_memory_offset)
}
unsafe fn active_level_4_table(physical_memory_offset: VirtAddr) -> &'static mut PageTable {
use x86_64::registers::control::Cr3;
let (level_4_table_frame, _) = Cr3::read();
let phys = level_4_table_frame.start_address();
let virt = physical_memory_offset + phys.as_u64();
let page_table_ptr: *mut PageTable = virt.as_mut_ptr();
// THIS IS UNSAFE
&mut *page_table_ptr
}
fn translate_addr_inner(addr: VirtAddr, physical_memory_offset: VirtAddr) -> Option<PhysAddr> {
use x86_64::registers::control::Cr3;
use x86_64::structures::paging::page_table::FrameError;
let (level_4_table_frame, _) = Cr3::read();
let table_indexes = [
addr.p4_index(),
addr.p3_index(),
addr.p2_index(),
addr.p1_index(),
];
let mut frame = level_4_table_frame;
for &index in &table_indexes {
// convert the frame into a page table reference
let virt = physical_memory_offset + frame.start_address().as_u64();
let table_ptr: *const PageTable = virt.as_ptr();
let table = unsafe { &*table_ptr };
let entry = &table[index];
frame = match entry.frame() {
Ok(frame) => frame,
Err(FrameError::FrameNotPresent) => return None,
Err(FrameError::HugeFrame) => panic!["huge pages not supported"],
};
}
Some(frame.start_address() + u64::from(addr.page_offset()))
}
pub unsafe fn translate_addr(addr: VirtAddr, physical_memory_offset: VirtAddr) -> Option<PhysAddr> {
translate_addr_inner(addr, physical_memory_offset)
}
pub fn create_example_mapping(
page: Page,
mapper: &mut OffsetPageTable,
frame_allocator: &mut impl FrameAllocator<Size4KiB>,
) {
use x86_64::structures::paging::PageTableFlags as Flags;
let frame = PhysFrame::containing_address(PhysAddr::new(0xb8000));
let flags = Flags::PRESENT | Flags::WRITABLE;
let map_to_result = unsafe { mapper.map_to(page, frame, flags, frame_allocator) };
map_to_result.expect("map_to failed").flush();
}
pub struct EmptyFrameAllocator;
unsafe impl FrameAllocator<Size4KiB> for EmptyFrameAllocator {
fn allocate_frame(&mut self) -> Option<PhysFrame<Size4KiB>> {
None
}
}

View file

@ -1,13 +1,15 @@
use x86_64::instructions::hlt; use x86_64::instructions::hlt;
use bootloader::BootInfo;
pub mod drivers; pub mod drivers;
pub mod gdt; pub mod gdt;
pub mod init; pub mod init;
pub mod interrupts; pub mod interrupts;
#[no_mangle] pub mod memory;
pub extern "C" fn _start() -> ! { // #[no_mangle]
crate::kmain::kernel_main(); // pub extern "C" fn _start(boot_info: &'static BootInfo) -> ! {
sloop(); // crate::kmain::kernel_main(boot_info);
} // // sloop();
// }
#[allow(unused)] #[allow(unused)]
pub fn shutdown() -> ! { pub fn shutdown() -> ! {

View file

@ -1,15 +1,23 @@
#![allow(clippy::empty_loop)] #![allow(clippy::empty_loop)]
use crate::{ use crate::{
arch::{drivers::graphics::GraphicsBuffer, init}, arch::{
drivers::graphics::GraphicsBuffer,
init,
memory::{self, translate_addr},
sloop,
},
driver_traits::{graphics::Graphics, serial::Serial}, driver_traits::{graphics::Graphics, serial::Serial},
relib::math::rand::{linearshift::LinearShiftRegister, prand::PRand, RAND_HANDLE, RNG}, relib::math::rand::{linearshift::LinearShiftRegister, prand::PRand, RAND_HANDLE, RNG},
serial_print, serial_println, serial_print, serial_println,
}; };
use bootloader::{entry_point, BootInfo};
use lazy_static::lazy_static; use lazy_static::lazy_static;
use x86_64::{VirtAddr, structures::paging::Page};
#[no_mangle] #[no_mangle]
#[allow(unconditional_recursion)] #[allow(unconditional_recursion)]
pub extern "C" fn stack_overflow() -> u8 { pub extern "C" fn stack_overflow() -> u8 {
stack_overflow(); stack_overflow();
// meme number
69 // NOTE: Any specific reason for this number asside from memes? 69 // NOTE: Any specific reason for this number asside from memes?
} }
@ -19,8 +27,10 @@ lazy_static! {
pub static ref KEY_BUFFER: [DecodedKey; 256] = [DecodedKey::RawKey(123); 256]; pub static ref KEY_BUFFER: [DecodedKey; 256] = [DecodedKey::RawKey(123); 256];
pub static ref KEY_BUFFER_POINTER: u8 = 0; pub static ref KEY_BUFFER_POINTER: u8 = 0;
} }
// Defines the entry point
entry_point![kernel_main];
#[no_mangle] #[no_mangle]
pub extern "C" fn kernel_main() { pub fn kernel_main(boot_info: &'static BootInfo) -> ! {
init::init(); init::init();
GraphicsBuffer::draw(); GraphicsBuffer::draw();
@ -44,9 +54,20 @@ pub extern "C" fn kernel_main() {
// x.dump_flags(); // x.dump_flags();
} }
let phys_mem_offset = VirtAddr::new(boot_info.physical_memory_offset);
let mut mapper = unsafe { memory::init(phys_mem_offset) };
let mut frame_allocator = memory::EmptyFrameAllocator;
let page = Page::containing_address(VirtAddr::new(0));
memory::create_example_mapping(page, &mut mapper, &mut frame_allocator);
let page_ptr: *mut u64 = page.start_address().as_mut_ptr();
unsafe { page_ptr.offset(400).write_volatile(0xf021_f077_f065_f04e) };
// stack_overflow(); // stack_overflow();
// crate::arch::shutdown(); // crate::arch::shutdown();
loop {} sloop()
} }
// TODO: reimplement for the random handler // TODO: reimplement for the random handler
pub fn seed_rng() -> PRand { pub fn seed_rng() -> PRand {