Remove x86_64 crate

loader/Cargo.lock

@@ -14,6 +14,12 @@ version = "0.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc827186963e592360843fb5ba4b973e145841266c1357f7180c43526f2e5b61"
 
+[[package]]
+name = "bitfield"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c821a6e124197eb56d907ccc2188eab1038fb919c914f47976e64dd8dbc855d1"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -51,12 +57,12 @@ checksum = "4445909572dbd556c457c849c4ca58623d84b27c8fff1e74b0b4227d8b90d17b"
 name = "loader"
 version = "0.0.1"
 dependencies = [
+ "bitfield",
  "com_logger",
  "elf",
  "log",
  "static-alloc",
  "uefi",
- "x86_64",
 ]
 
 [[package]]
@@ -219,12 +225,6 @@ version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
 
-[[package]]
-name = "volatile"
-version = "0.4.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "442887c63f2c839b346c192d047a7c87e73d0689c9157b00b53dcc27dd5ea793"
-
 [[package]]
 name = "x86"
 version = "0.52.0"
@@ -235,15 +235,3 @@ dependencies = [
  "bitflags 1.3.2",
  "raw-cpuid",
 ]
-
-[[package]]
-name = "x86_64"
-version = "0.15.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4bc79523af8abf92fb1a970c3e086c5a343f6bcc1a0eb890f575cbb3b45743df"
-dependencies = [
- "bit_field",
- "bitflags 2.6.0",
- "rustversion",
- "volatile",
-]

loader/Cargo.toml

@@ -4,9 +4,9 @@ version = "0.0.1"
 edition = "2021"
 
 [dependencies]
+bitfield = "0.15.0"
 com_logger = { git = "https://git.strypsteen.com/mathieu/com_logger", version = "0.1.1" }
 elf = {version = "0.7.4", default-features = false}
 log = "0.4.22"
 static-alloc = "0.2.5"
 uefi = {version = "0.28.0"}
-x86_64 = {version = "0.15.1", default-features = false, features = ["instructions"]}

loader/src/paging.rs

@@ -1,26 +1,44 @@
-use core::alloc::Layout;
+use core::{alloc::Layout, arch::asm};
 
 use alloc::alloc::alloc_zeroed;
+use bitfield::bitfield;
 use uefi::table::boot::{MemoryMap, MemoryType};
-use x86_64::{
-    registers::control::{Cr3, Cr3Flags},
-    structures::paging::{PageTable, PageTableFlags, PhysFrame},
-    PhysAddr,
-};
 
 use crate::elf;
 
+bitfield! {
+    struct PageEntry(u64);
+    present, set_present: 1, 0;
+    write, set_write: 2, 1;
+    user, set_user: 3, 2;
+    write_through, set_write_through: 4, 3;
+    cache_disable, set_cache_disable: 5, 4;
+    accessed, set_accessed: 6, 5;
+    dirty, set_dirty: 7, 6;
+    page_size, set_page_size: 8, 7;
+    global, set_global: 9, 8;
+    available, set_available: 11, 9;
+    address, set_address: 63, 12;
+}
+
+#[repr(C)]
+#[repr(align(0x1000))]
+struct PageTable {
+    entries: [PageEntry; 512],
+}
+
 fn get_table_entry(table: &mut PageTable, i: usize) -> &mut PageTable {
-    if table[i].is_unused() {
+    if table.entries[i].present() == 0 {
         let layout = Layout::new::<PageTable>().align_to(0x1000).unwrap();
         let new_table;
         unsafe {
             new_table = alloc_zeroed(layout);
         }
-        let addr = PhysAddr::new(new_table as u64);
+        table.entries[i].set_address(new_table as u64 / 0x1000);
-        table[i].set_addr(addr, PageTableFlags::PRESENT | PageTableFlags::WRITABLE);
+        table.entries[i].set_present(1);
+        table.entries[i].set_write(1);
     }
-    let ptr = table[i].addr().as_u64() as *mut PageTable;
+    let ptr = (table.entries[i].address() * 0x1000) as *mut PageTable;
     unsafe {
         return ptr.as_mut().unwrap();
     }
@@ -34,8 +52,9 @@ fn map(pml4: &mut PageTable, mut virt: usize, phys: usize) {
     let pdpt = get_table_entry(pml4, pml4_i);
     let directory = get_table_entry(pdpt, pdpt_i);
     let table = get_table_entry(directory, directory_i);
-    let phys_addr = PhysAddr::new(phys as u64);
+    table.entries[table_i].set_address(phys as u64 / 0x1000);
-    table[table_i].set_addr(phys_addr, PageTableFlags::PRESENT | PageTableFlags::WRITABLE)
+    table.entries[table_i].set_present(1);
+    table.entries[table_i].set_write(1);
 }
 pub fn setup_paging(memory_map: &MemoryMap, kernel_start: u64, kernel_size: usize) {
     let pml4;
@@ -62,9 +81,7 @@ pub fn setup_paging(memory_map: &MemoryMap, kernel_start: u64, kernel_size: usiz
         let phys = kernel_start as usize + i * 0x1000;
         map(pml4, virt, phys);
     }
-    let pml4_addr = PhysAddr::new(pml4 as *const PageTable as u64);
-    let frame = PhysFrame::from_start_address(pml4_addr).unwrap();
     unsafe {
-        Cr3::write(frame, Cr3Flags::empty());
+        asm!("mov cr3, {}", in(reg) pml4 as *const PageTable as u64);
     }
 }