gemini3-pro

Signed-off-by: ale <ale@manalejandro.com>

.cargo/config.toml

@@ -0,0 +1,14 @@
+[build]
+target = "x86_64-unknown-none"
+
+[target.x86_64-unknown-none]
+runner = "qemu-system-x86_64 -kernel"
+rustflags = [
+    "-C", "relocation-model=static",
+    "-C", "link-arg=-Tkernel/linker.ld",
+    "-C", "link-arg=-no-pie"
+]
+
+[unstable]
+build-std = ["core", "alloc"]
+build-std-features = ["compiler-builtins-mem"]

Makefile

@@ -29,7 +29,7 @@ all: kernel modules drivers
 # Build the core kernel
 kernel:
 	@echo "Building Rust kernel ($(ARCH), $(BUILD_TYPE))"
-	$(CARGO) build $(CARGO_FLAGS)
+	$(CARGO) build $(CARGO_FLAGS) --bin rust-kernel --target x86_64-unknown-none
 
 # Build kernel modules
 modules: $(RUST_MODULES)

README.md

@@ -92,11 +92,11 @@ make clean && RUSTFLAGS="-Awarnings" make kernel
 ### Basic Execution
 ```bash
 # Run kernel in QEMU (basic)
-qemu-system-x86_64 -kernel target/release/rust-kernel
+qemu-system-x86_64 -kernel kernel/target/x86_64-unknown-none/release/rust-kernel
 
 # Run with more memory and serial output
 qemu-system-x86_64 \
-    -kernel target/release/rust-kernel \
+    -kernel kernel/target/x86_64-unknown-none/release/rust-kernel \
     -m 128M \
     -serial stdio \
     -no-reboot \
@@ -107,7 +107,7 @@ qemu-system-x86_64 \
 ```bash
 # Full-featured QEMU run with debugging
 qemu-system-x86_64 \
-    -kernel target/release/rust-kernel \
+    -kernel kernel/target/x86_64-unknown-none/release/rust-kernel \
     -m 256M \
     -smp 2 \
     -serial stdio \
@@ -124,13 +124,13 @@ qemu-system-x86_64 \
 ```bash
 # Run QEMU with GDB server
 qemu-system-x86_64 \
-    -kernel target/release/rust-kernel \
+    -kernel kernel/target/x86_64-unknown-none/release/rust-kernel \
     -s -S \
     -m 128M \
     -serial stdio
 
 # In another terminal, connect GDB
-gdb target/release/rust-kernel
+gdb kernel/target/x86_64-unknown-none/release/rust-kernel
 (gdb) target remote localhost:1234
 (gdb) continue
 ```
@@ -315,8 +315,8 @@ perf counters       # Show performance counters
 - **Memory Mapping**: Support for memory-mapped I/O and files
 
 ### Process & Task Management  
-- **Preemptive Scheduling**: Priority-based with round-robin
+- **Preemptive Scheduling**: Priority-based with round-robin and CFS (Completely Fair Scheduler)
-- **Context Switching**: Full CPU context preservation
+- **Context Switching**: Full CPU context preservation including GPRs, segment registers, and control registers
 - **Kernel Threads**: Lightweight kernel task execution
 - **Process States**: Running, ready, waiting, zombie states
 
@@ -360,6 +360,7 @@ perf counters       # Show performance counters
 
 ### 📋 **Future Enhancements**
 - [ ] SMP (multi-processor) support
+- [ ] ACPI (Advanced Configuration and Power Interface) support
 - [ ] Advanced file systems (ext2, FAT32)
 - [ ] Complete TCP/IP networking stack
 - [ ] Graphics and display support

build_and_test.sh

@@ -8,6 +8,9 @@ set -e  # Exit on any error
 echo "=== Rust Kernel Build and Test Script ==="
 echo "Starting comprehensive build and validation..."
 
+# Enable unstable features on stable compiler
+export RUSTC_BOOTSTRAP=1
+
 # Colors for output
 RED='\033[0;31m'
 GREEN='\033[0;32m'
@@ -84,7 +87,7 @@ fi
 # Run Clippy lints (if available)
 print_status "Running Clippy lints..."
 if command -v cargo-clippy &> /dev/null; then
-    if RUSTFLAGS="-Awarnings" cargo clippy -- -D warnings > /tmp/clippy.log 2>&1; then
+    if cargo clippy -- -D warnings > /tmp/clippy.log 2>&1; then
         print_success "Clippy lints passed"
     else
         print_warning "Clippy found issues (continuing with build)"
@@ -97,18 +100,18 @@ fi
 
 # Build in debug mode
 print_status "Building kernel in debug mode..."
-run_with_status "RUSTFLAGS='-Awarnings' cargo check" "Debug build check"
+run_with_status "cargo check" "Debug build check"
 print_success "Debug build completed successfully"
 
 # Build in release mode
 print_status "Building kernel in release mode..."
-run_with_status "RUSTFLAGS='-Awarnings' cargo check --release" "Release build check"
+run_with_status "cargo check --release" "Release build check"
 print_success "Release build completed successfully"
 
 # Build with make (if Makefile exists)
 if [ -f "Makefile" ]; then
     print_status "Building with Makefile..."
-    run_with_status "RUSTFLAGS='-Awarnings' make kernel" "Makefile build"
+    run_with_status "make kernel" "Makefile build"
     print_success "Makefile build completed successfully"
 else
     print_warning "Makefile not found, skipping make build"
@@ -125,6 +128,15 @@ if [ -f "target/release/deps/kernel-"*.rlib ]; then
     print_status "Kernel library size: $KERNEL_SIZE"
 fi
 
+# Create ISO
+print_status "Creating bootable ISO..."
+cp target/x86_64-unknown-none/release/rust-kernel iso/boot/rust-kernel
+if grub-mkrescue -o rust-kernel.iso iso > /dev/null 2>&1; then
+    print_success "ISO created: rust-kernel.iso"
+else
+    print_warning "Failed to create ISO (grub-mkrescue not found or failed)"
+fi
+
 # Create build report
 BUILD_REPORT="build_report.txt"
 print_status "Generating build report..."
@@ -198,7 +210,7 @@ print_status "Test suites available: 15+ test categories"
 
 echo ""
 echo "To test the kernel:"
-echo "  1. Boot in QEMU: qemu-system-x86_64 -kernel target/release/..."
+echo "  1. Boot in QEMU: qemu-system-x86_64 -cdrom rust-kernel.iso"
 echo "  2. Use shell commands like: 'test run', 'sysinfo', 'health'"
 echo "  3. Monitor system status with: 'diag', 'perf', 'mem'"
 

clippy.toml

@@ -1,21 +1,21 @@
 # Clippy configuration for kernel development
 
-allow = [
+# allow = [
-    "clippy::missing_errors_doc",
+#     "clippy::missing_errors_doc",
-    "clippy::missing_panics_doc", 
+#     "clippy::missing_panics_doc", 
-    "clippy::module_name_repetitions",
+#     "clippy::module_name_repetitions",
-    "clippy::inline_always",
+#     "clippy::inline_always",
-    "clippy::must_use_candidate",
+#     "clippy::must_use_candidate",
-    "clippy::cast_possible_truncation",
+#     "clippy::cast_possible_truncation",
-    "clippy::cast_sign_loss",
+#     "clippy::cast_sign_loss",
-    "clippy::cast_possible_wrap",
+#     "clippy::cast_possible_wrap",
-    "clippy::similar_names",
+#     "clippy::similar_names",
-    "clippy::too_many_lines",
+#     "clippy::too_many_lines",
-    "clippy::unused_self"
+#     "clippy::unused_self"
-]
+# ]
 
 # Kernel-specific thresholds
 cognitive-complexity-threshold = 30
 too-many-arguments-threshold = 8
 type-complexity-threshold = 250
-single-char-lifetime-names-threshold = 4
+# single-char-lifetime-names-threshold = 4

iso/boot/grub/grub.cfg

@@ -0,0 +1,7 @@
+set timeout=0
+set default=0
+
+menuentry "Rust Kernel" {
+    multiboot2 /boot/rust-kernel
+    boot
+}

kernel/.cargo/config.toml

@@ -1,6 +1,17 @@
 [target.x86_64-unknown-none]
 rustflags = [
-    "-C", "link-arg=-Tlinker.ld",
     "-C", "link-arg=--no-dynamic-linker", 
     "-C", "link-arg=-static",
+    "-C", "relocation-model=static",
+    "-C", "link-arg=-no-pie",
+    "-C", "link-arg=-z", 
+    "-C", "link-arg=max-page-size=0x1000",
+    "-C", "link-arg=--oformat=elf64-x86-64",
 ]
+
+[build]
+target = "x86_64-unknown-none"
+
+[unstable]
+build-std = ["core", "alloc"]
+build-std-features = ["compiler-builtins-mem"]

kernel/Cargo.toml

@@ -14,7 +14,6 @@ crate-type = ["rlib"]
 spin = "0.9"
 bitflags = "2.4"
 linked_list_allocator = "0.10"
-once_cell = { version = "1.19", default-features = false, features = ["critical-section"] }
 
 [features]
 default = []

kernel/build.rs

@@ -1,11 +1,18 @@
 // SPDX-License-Identifier: GPL-2.0
 
+use std::env;
+use std::fs;
+use std::path::PathBuf;
+
 fn main() {
-	// Build assembly files with rustc
-	println!("cargo:rerun-if-changed=src/arch/x86_64/boot.s");
-	println!("cargo:rerun-if-changed=src/arch/x86_64/exceptions.s");
 	println!("cargo:rerun-if-changed=linker.ld");
 
-	// Tell Cargo to link against the linker script
+	let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
-	println!("cargo:rustc-link-arg=-Tlinker.ld");
+
+	// Copy linker script to OUT_DIR so the linker can find it
+	let linker_script = out_dir.join("linker.ld");
+	fs::copy("linker.ld", &linker_script).expect("Failed to copy linker script");
+
+	// Tell cargo to pass the linker script to the linker
+	println!("cargo:rustc-link-arg=-T{}", linker_script.display());
 }

kernel/linker.ld

@@ -3,36 +3,51 @@
 
 ENTRY(_start)
 
+/* Program headers (segments) for ELF */
+PHDRS
+{
+    text    PT_LOAD FLAGS(5); /* Read + Execute */
+    rodata  PT_LOAD FLAGS(4); /* Read only */
+    data    PT_LOAD FLAGS(6); /* Read + Write */
+}
+
 SECTIONS
 {
     /* Start at 1MB (standard kernel load address) */
-    . = 1M;
+    . = 0x100000;
     
-    /* Multiboot header must be early */
+    /* Multiboot header MUST be first */
-    .multiboot_header : {
+    .multiboot_header : ALIGN(8) {
-        *(.multiboot_header)
+        KEEP(*(.multiboot_header))
-    }
+    } :text
+    
+    /* Boot and text sections */
+    .boot : ALIGN(8) {
+        *(.text._start)
+        *(.boot)
+    } :text
+    
+    /* Rest of code section */
+    .text : ALIGN(4K) {
+        *(.text .text.*)
+    } :text
     
     /* Read-only sections */
     .rodata : ALIGN(4K) {
         *(.rodata .rodata.*)
-    }
+    } :rodata
-    
-    /* Code section */
-    .text : ALIGN(4K) {
-        *(.text .text.*)
-    }
     
     /* Read-write data */
     .data : ALIGN(4K) {
         *(.data .data.*)
-    }
+        *(.got .got.*)
+    } :data
     
     /* BSS section (uninitialized data) */
     .bss : ALIGN(4K) {
         *(.bss .bss.*)
         *(COMMON)
-    }
+    } :data
     
     /* Kernel end marker */
     __kernel_end = .;

kernel/src/arch/x86_64/boot.S

@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Multiboot header for the Rust kernel */
+
+.section .multiboot_header
+.align 8
+
+/* Multiboot2 header */
+multiboot_header_start:
+    .long 0xe85250d6                /* magic number */
+    .long 0                         /* architecture: i386 */
+    .long multiboot_header_end - multiboot_header_start  /* header length */
+    .long -(0xe85250d6 + 0 + (multiboot_header_end - multiboot_header_start))  /* checksum */
+
+    /* Information request tag */
+    .short 1                        /* type */
+    .short 0                        /* flags */
+    .long 12                        /* size */
+    .long 6                         /* memory map */
+
+    /* End tag */
+    .short 0                        /* type */
+    .short 0                        /* flags */  
+    .long 8                         /* size */
+multiboot_header_end:
+
+.section .text
+.global _start
+.code32
+
+_start:
+    /* Set up stack */
+    mov $stack_top, %esp
+    
+    /* Reset EFLAGS */
+    pushl $0
+    popf
+    
+    /* Check if we were loaded by multiboot */
+    cmp $0x36d76289, %eax
+    jne .no_multiboot
+    
+    /* Save multiboot info pointer */
+    push %ebx
+    
+    /* Call kernel main */
+    call kernel_main
+    
+    /* Halt if kernel returns */
+    cli
+.hang:
+    hlt
+    jmp .hang
+
+.no_multiboot:
+    /* No multiboot - just halt */
+    cli
+    hlt
+
+.section .bss
+.align 16
+stack_bottom:
+    .skip 16384  /* 16KB stack */
+stack_top:
+
+.section .data
+multiboot_info_ptr:
+    .long 0

kernel/src/arch/x86_64/boot.s

@@ -1,7 +1,15 @@
 # SPDX-License-Identifier: GPL-2.0
 # Rust Kernel boot entry point for x86_64
 
-.section .multiboot_header
+.section .multiboot_header, "a"
+# Multiboot 1 Header
+.align 4
+    .long 0x1BADB002                # magic
+    .long 0x00000003                # flags (align + meminfo)
+    .long -(0x1BADB002 + 0x00000003) # checksum
+
+# Multiboot 2 Header
+.align 8
 header_start:
     # Multiboot2 header
     .long 0xe85250d6                # magic number
@@ -21,6 +29,8 @@ header_end:
 .section .bss
 multiboot_magic_store:
     .skip 4
+multiboot_info_store:
+    .skip 4
 # Stack for the kernel
 .global stack_bottom
 .global stack_top
@@ -30,16 +40,16 @@ stack_top:
 
 # Bootstrap page tables
 .align 4096
-.global boot_page_directory_ptr_table
+.global boot_pml4
-boot_page_directory_ptr_table:
+boot_pml4:
     .skip 4096
 
-.global boot_page_directory_table
+.global boot_pdp
-boot_page_directory_table:
+boot_pdp:
     .skip 4096
 
-.global boot_page_table
+.global boot_pd
-boot_page_table:
+boot_pd:
     .skip 4096
 
 .section .rodata
@@ -49,7 +59,7 @@ gdt64:
     .quad (1<<44) | (1<<47) | (1<<41) | (1<<43) | (1<<53) # code segment
 .set gdt64.data, . - gdt64  
     .quad (1<<44) | (1<<47) | (1<<41) # data segment
-.set gdt64.pointer, . - gdt64
+gdt64.pointer:
     .word . - gdt64 - 1         # length
     .quad gdt64                 # address
 
@@ -61,13 +71,21 @@ _start:
     movl $stack_top, %esp
     movl %esp, %ebp
     
-    # Save multiboot information before we lose it
+    # Save multiboot information before we lose it or clobber EAX
     movl %eax, multiboot_magic_store
     movl %ebx, multiboot_info_store
     
+    # Restore magic for check (or use stored value)
+    movl multiboot_magic_store, %eax
+
     # Check for multiboot
     cmpl $0x36d76289, %eax
-    jne no_multiboot
+    je .multiboot_ok
+    cmpl $0x2BADB002, %eax
+    je .multiboot_ok
+    jmp no_multiboot
+
+.multiboot_ok:
     
     # Check for CPUID
     call check_cpuid
@@ -88,7 +106,7 @@ _start:
     movl %eax, %cr4
     
     # Load page table
-    movl $boot_page_directory_ptr_table, %eax
+    movl $boot_pml4, %eax
     movl %eax, %cr3
     
     # Enable long mode
@@ -121,7 +139,7 @@ check_cpuid:
     pushl %ecx
     popfl
     cmpl %ecx, %eax
-    sete %al
+    setne %al
     movzbl %al, %eax
     ret
 
@@ -136,7 +154,7 @@ check_long_mode:
     movl $0x80000001, %eax
     cpuid
     testl $1 << 29, %edx
-    setz %al
+    setnz %al
     movzbl %al, %eax
     ret
     
@@ -145,30 +163,28 @@ check_long_mode:
     ret
 
 setup_page_tables:
-    # Map first 2MB with 2MB pages
+    # Map PML4[0] -> PDP
-    # PDP table entry
+    movl $boot_pdp, %eax
-    movl $boot_page_directory_table, %eax
     orl $0b11, %eax     # present + writable
-    movl %eax, boot_page_directory_ptr_table
+    movl %eax, boot_pml4
     
-    # PD table entry  
+    # Map PDP[0] -> PD
-    movl $boot_page_table, %eax
+    movl $boot_pd, %eax
     orl $0b11, %eax     # present + writable
-    movl %eax, boot_page_directory_table
+    movl %eax, boot_pdp
     
-    # Page table entries (identity map first 2MB)
+    # Map PD[0..511] -> 2MB Pages (Identity map 0-1GB)
-    movl $boot_page_table, %edi
+    movl $boot_pd, %edi
-    movl $0, %ebx
+    movl $0, %ebx       # Physical address
-    movl $512, %ecx
+    movl $512, %ecx     # 512 entries
     
-.map_page_table:
+.map_pd_loop:
     movl %ebx, %eax
-    shll $12, %eax    # multiply by 4096 (page size)
+    orl $0b10000011, %eax # present + writable + huge (2MB)
-    orl $0b11, %eax   # present + writable
     movl %eax, (%edi)
-    addl $8, %edi
+    addl $8, %edi       # Next entry
-    incl %ebx
+    addl $0x200000, %ebx # Next 2MB
-    loop .map_page_table
+    loop .map_pd_loop
     
     ret
 
@@ -228,6 +244,10 @@ print_string:
     ret
 
 no_multiboot:
+    # DEBUG: Print 'M' to serial port COM1
+    mov $0x3f8, %dx
+    mov $'M', %al
+    out %al, %dx
     movl $no_multiboot_msg, %esi
     call print_string_32
     jmp halt32
@@ -272,3 +292,5 @@ no_cpuid_msg:
     
 no_long_mode_msg:
     .asciz "ERROR: Long mode not supported"
+
+

kernel/src/arch/x86_64/boot_entry.s

@@ -1,44 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-# Kernel entry point - multiboot compliant
-
-.section .multiboot
-.align 4
-
-# Multiboot header
-multiboot_header:
-    .long 0x1BADB002                # Magic number
-    .long 0x00000003                # Flags (align modules on page boundaries + memory info)
-    .long -(0x1BADB002 + 0x00000003) # Checksum
-
-.section .bss
-.align 16
-stack_bottom:
-    .skip 16384                     # 16 KB stack
-stack_top:
-
-.section .text
-.global _start
-.type _start, @function
-
-_start:
-    # Set up the stack
-    mov $stack_top, %esp
-    
-    # Reset EFLAGS
-    pushl $0
-    popf
-    
-    # Push multiboot parameters
-    pushl %ebx                      # Multiboot info structure
-    pushl %eax                      # Multiboot magic number
-    
-    # Call the kernel main function
-    call kernel_main_multiboot
-    
-    # If kernel returns (shouldn't happen), hang
-    cli
-hang:
-    hlt
-    jmp hang
-
-.size _start, . - _start

kernel/src/arch/x86_64/context.rs

@@ -166,31 +166,87 @@ impl Context {
 
 	/// Restore CPU context and switch to it
 	pub unsafe fn restore(&self) -> ! {
-		// For now, implement a simplified version that doesn't cause register pressure
+		// Restore context using the pointer to self (passed in rdi)
-		// TODO: Implement full context switching with proper register restoration
-
-		// Restore page table
-		asm!("mov cr3, {}", in(reg) self.cr3);
-
-		// Set up a minimal context switch by jumping to the target RIP
-		// This is a simplified version - a full implementation would restore all
-		// registers
 		asm!(
-		    "mov rsp, {}",
+			// Restore CR3 (Page Table)
-		    "push {}",    // CS for iretq
+			"mov rax, [rdi + 144]",
-		    "push {}",    // RIP for iretq
+			"mov cr3, rax",
-		    "pushfq",     // Push current flags
+
+			// Switch stack to the target stack
+			"mov rsp, [rdi + 56]",
+
+			// Construct interrupt stack frame for iretq
+			// Stack layout: SS, RSP, RFLAGS, CS, RIP
+
+			// SS
+			"movzx rax, word ptr [rdi + 162]",
+			"push rax",
+
+			// RSP (target stack pointer)
+			"mov rax, [rdi + 56]",
+			"push rax",
+
+			// RFLAGS
+			"mov rax, [rdi + 136]",
+			"push rax",
+
+			// CS
+			"movzx rax, word ptr [rdi + 152]",
+			"push rax",
+
+			// RIP
+			"mov rax, [rdi + 128]",
+			"push rax",
+
+			// Push General Purpose Registers onto the new stack
+			// We push them in reverse order of popping
+			"push qword ptr [rdi + 0]",   // rax
+			"push qword ptr [rdi + 8]",   // rbx
+			"push qword ptr [rdi + 16]",  // rcx
+			"push qword ptr [rdi + 24]",  // rdx
+			"push qword ptr [rdi + 32]",  // rsi
+			"push qword ptr [rdi + 40]",  // rdi
+			"push qword ptr [rdi + 48]",  // rbp
+			// rsp is handled by stack switch
+			"push qword ptr [rdi + 64]",  // r8
+			"push qword ptr [rdi + 72]",  // r9
+			"push qword ptr [rdi + 80]",  // r10
+			"push qword ptr [rdi + 88]",  // r11
+			"push qword ptr [rdi + 96]",  // r12
+			"push qword ptr [rdi + 104]", // r13
+			"push qword ptr [rdi + 112]", // r14
+			"push qword ptr [rdi + 120]", // r15
+
+			// Restore Segment Registers
+			"mov ax, [rdi + 154]", // ds
+			"mov ds, ax",
+			"mov ax, [rdi + 156]", // es
+			"mov es, ax",
+			"mov ax, [rdi + 158]", // fs
+			"mov fs, ax",
+			"mov ax, [rdi + 160]", // gs
+			"mov gs, ax",
+
+			// Pop General Purpose Registers
+			"pop r15",
+			"pop r14",
+			"pop r13",
+			"pop r12",
+			"pop r11",
+			"pop r10",
+			"pop r9",
+			"pop r8",
+			"pop rbp",
+			"pop rdi", // This restores the target rdi
+			"pop rsi",
+			"pop rdx",
+			"pop rcx",
+			"pop rbx",
 			"pop rax",
-		    "or rax, 0x200", // Enable interrupts
+
-		    "push rax",   // RFLAGS for iretq
+			// Return from interrupt (restores RIP, CS, RFLAGS, RSP, SS)
-		    "push {}",    // CS again
-		    "push {}",    // RIP again
 			"iretq",
-		    in(reg) self.rsp,
+			in("rdi") self,
-		    in(reg) self.cs as u64,
-		    in(reg) self.rip,
-		    in(reg) self.cs as u64,
-		    in(reg) self.rip,
 			options(noreturn)
 		);
 	}

kernel/src/boot.rs

@@ -74,7 +74,9 @@ pub fn get_boot_info() -> &'static BootInfo {
 
 /// Update boot information
 pub unsafe fn update_boot_info<F>(f: F)
-where F: FnOnce(&mut BootInfo) {
+where
+	F: FnOnce(&mut BootInfo),
+{
 	f(&mut BOOT_INFO);
 }
 
@@ -114,7 +116,8 @@ pub mod multiboot {
 	pub struct BootMemoryInfo {
 		pub total_memory: u64,
 		pub available_memory: u64,
-		pub memory_regions: alloc::vec::Vec<MemoryMapEntry>,
+		pub memory_regions: [MemoryMapEntry; 32],
+		pub region_count: usize,
 	}
 
 	impl BootMemoryInfo {
@@ -122,7 +125,13 @@ pub mod multiboot {
 			Self {
 				total_memory: 0,
 				available_memory: 0,
-				memory_regions: alloc::vec::Vec::new(),
+				memory_regions: [MemoryMapEntry {
+					base_addr: 0,
+					length: 0,
+					type_: 0,
+					reserved: 0,
+				}; 32],
+				region_count: 0,
 			}
 		}
 
@@ -131,17 +140,20 @@ pub mod multiboot {
 				self.available_memory += entry.length;
 			}
 			self.total_memory += entry.length;
-			self.memory_regions.push(entry);
+			if self.region_count < 32 {
+				self.memory_regions[self.region_count] = entry;
+				self.region_count += 1;
+			}
 		}
 	}
 
 	/// Parse multiboot2 information and initialize memory management
 	pub fn init_memory_from_multiboot(multiboot_addr: usize) -> Result<()> {
-		info!("Parsing multiboot information at 0x{:x}", multiboot_addr);
+		crate::println!("Parsing multiboot information at 0x{:x}", multiboot_addr);
 
 		let multiboot_info = unsafe { &*(multiboot_addr as *const MultibootInfo) };
 
-		info!("Multiboot info size: {} bytes", multiboot_info.total_size);
+		crate::println!("Multiboot info size: {} bytes", multiboot_info.total_size);
 
 		// Parse memory map from multiboot info
 		let mut memory_info = BootMemoryInfo::new();
@@ -166,12 +178,13 @@ pub mod multiboot {
 		}
 
 		// Initialize page allocator with available memory
-		for region in &memory_info.memory_regions {
+		for i in 0..memory_info.region_count {
+			let region = &memory_info.memory_regions[i];
 			if region.type_ == memory_type::AVAILABLE {
 				let start_pfn = region.base_addr / 4096;
 				let end_pfn = (region.base_addr + region.length) / 4096;
 
-				info!(
+				crate::println!(
 					"Adding memory region: 0x{:x}-0x{:x}",
 					region.base_addr,
 					region.base_addr + region.length
@@ -185,9 +198,9 @@ pub mod multiboot {
 			}
 		}
 
-		info!("Memory initialization from multiboot completed");
+		crate::println!("Memory initialization from multiboot completed");
-		info!("Total memory: {} bytes", memory_info.total_memory);
+		crate::println!("Total memory: {} bytes", memory_info.total_memory);
-		info!("Available memory: {} bytes", memory_info.available_memory);
+		crate::println!("Available memory: {} bytes", memory_info.available_memory);
 
 		Ok(())
 	}

kernel/src/enhanced_scheduler.rs

@@ -462,7 +462,9 @@ static ENHANCED_SCHEDULER: Spinlock<Option<EnhancedScheduler>> = Spinlock::new(N
 
 /// Helper to get scheduler reference safely
 fn with_scheduler<T, F>(f: F) -> Option<T>
-where F: FnOnce(&mut EnhancedScheduler) -> T {
+where
+	F: FnOnce(&mut EnhancedScheduler) -> T,
+{
 	let mut scheduler_option = ENHANCED_SCHEDULER.lock();
 	if let Some(ref mut scheduler) = *scheduler_option {
 		Some(f(scheduler))
@@ -473,7 +475,9 @@ where F: FnOnce(&mut EnhancedScheduler) -> T {
 
 /// Helper to get read-only scheduler reference safely
 fn with_scheduler_read<T, F>(f: F) -> Option<T>
-where F: FnOnce(&EnhancedScheduler) -> T {
+where
+	F: FnOnce(&EnhancedScheduler) -> T,
+{
 	let scheduler_option = ENHANCED_SCHEDULER.lock();
 	if let Some(ref scheduler) = *scheduler_option {
 		Some(f(scheduler))

kernel/src/fs/dentry.rs

@@ -257,25 +257,28 @@ impl DentryCache {
 }
 
 /// Global dentry cache
-static DCACHE: once_cell::sync::Lazy<DentryCache> =
+static DCACHE: spin::once::Once<DentryCache> = spin::once::Once::new();
-	once_cell::sync::Lazy::new(|| DentryCache::new());
+
+fn get_dcache() -> &'static DentryCache {
+	DCACHE.call_once(|| DentryCache::new())
+}
 
 /// Look up dentry in cache
 pub fn dcache_lookup(path: &str) -> Option<Arc<Dentry>> {
-	DCACHE.lookup(path)
+	get_dcache().lookup(path)
 }
 
 /// Insert dentry into cache
 pub fn dcache_insert(path: String, dentry: Arc<Dentry>) {
-	DCACHE.insert(path, dentry);
+	get_dcache().insert(path, dentry);
 }
 
 /// Remove dentry from cache
 pub fn dcache_remove(path: &str) -> Option<Arc<Dentry>> {
-	DCACHE.remove(path)
+	get_dcache().remove(path)
 }
 
 /// Prune dentry cache
 pub fn dcache_prune() {
-	DCACHE.prune();
+	get_dcache().prune();
 }

kernel/src/fs/mount.rs

@@ -194,12 +194,15 @@ impl MountNamespace {
 }
 
 /// Global mount namespace
-static INIT_MNT_NS: once_cell::sync::Lazy<Mutex<MountNamespace>> =
+static INIT_MNT_NS: spin::once::Once<Mutex<MountNamespace>> = spin::once::Once::new();
-	once_cell::sync::Lazy::new(|| Mutex::new(MountNamespace::new(1)));
+
+fn get_init_mnt_ns() -> &'static Mutex<MountNamespace> {
+	INIT_MNT_NS.call_once(|| Mutex::new(MountNamespace::new(1)))
+}
 
 /// Get the init mount namespace
 pub fn get_init_ns() -> &'static Mutex<MountNamespace> {
-	&INIT_MNT_NS
+	get_init_mnt_ns()
 }
 
 /// Mount a filesystem

kernel/src/lib.rs

@@ -18,6 +18,10 @@
 
 extern crate alloc;
 
+// Include boot assembly
+// #[cfg(target_arch = "x86_64")]
+// global_asm!(include_str!("arch/x86_64/boot.s"), options(att_syntax));
+
 pub mod arch;
 pub mod benchmark; // Performance benchmarking
 pub mod boot;
@@ -94,7 +98,7 @@ pub extern "C" fn kernel_main() -> ! {
 #[no_mangle]
 pub extern "C" fn kernel_main_multiboot(multiboot_magic: u32, multiboot_addr: u32) -> ! {
 	// Verify multiboot magic number
-	if multiboot_magic != 0x36d76289 {
+	if multiboot_magic != 0x36d76289 && multiboot_magic != 0x2BADB002 {
 		panic!("Invalid multiboot magic: 0x{:x}", multiboot_magic);
 	}
 
@@ -113,8 +117,8 @@ fn early_kernel_init() {
 		loop {}
 	}
 
-	info!("Rust Kernel v{} starting...", VERSION);
+	crate::println!("Rust Kernel v{} starting...", VERSION);
-	info!("Early kernel initialization");
+	crate::println!("Early kernel initialization");
 }
 
 /// Initialize memory management using multiboot information

kernel/src/main.rs

@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel main entry point
+
+#![no_std]
+#![no_main]
+
+extern crate kernel;
+
+use core::arch::global_asm;
+
+// Include boot assembly
+#[cfg(target_arch = "x86_64")]
+global_asm!(include_str!("arch/x86_64/boot.s"), options(att_syntax));
+
+use core::panic::PanicInfo;
+
+/// Multiboot1 header - placed at the very beginning
+#[repr(C)]
+#[repr(packed)]
+struct MultibootHeader {
+	magic: u32,
+	flags: u32,
+	checksum: u32,
+}
+
+/// Multiboot header must be in the first 8KB and be 4-byte aligned
+// #[link_section = ".multiboot_header"]
+// #[no_mangle]
+// #[used]
+// static MULTIBOOT_HEADER: MultibootHeader = MultibootHeader {
+// 	magic: 0x1BADB002,
+// 	flags: 0x00000000,
+// 	checksum: 0u32.wrapping_sub(0x1BADB002u32.wrapping_add(0x00000000)),
+// };
+
+/// Entry point called by boot.s assembly code
+/// This is just a wrapper to ensure the kernel crate is linked
+#[no_mangle]
+pub extern "C" fn rust_main() -> ! {
+	// This function shouldn't be called directly if boot.s calls kernel_main_multiboot
+	// But if it is called, we redirect to the kernel library
+	loop {
+		unsafe {
+			core::arch::asm!("hlt");
+		}
+	}
+}
+
+// Panic handler is defined in the kernel library
+
+#[no_mangle]
+pub extern "C" fn _start() -> ! {
+	loop {}
+}

kernel/src/memory/page.rs

@@ -2,7 +2,6 @@
 
 //! Page frame allocator
 
-use alloc::collections::BTreeSet;
 use core::sync::atomic::{AtomicU32, Ordering};
 
 use crate::error::{Error, Result};
@@ -98,34 +97,57 @@ pub static PAGE_ALLOCATOR: Spinlock<PageAllocator> = Spinlock::new(PageAllocator
 
 /// Page allocator implementation
 pub struct PageAllocator {
-	free_pages: BTreeSet<Pfn>,
+	free_list_head: Option<PhysAddr>,
 	total_pages: usize,
 	allocated_pages: usize,
+	free_count: usize,
 }
 
 impl PageAllocator {
 	pub const fn new() -> Self {
 		Self {
-			free_pages: BTreeSet::new(),
+			free_list_head: None,
 			total_pages: 0,
 			allocated_pages: 0,
+			free_count: 0,
 		}
 	}
 
 	/// Add a range of pages to the free list
 	pub fn add_free_range(&mut self, start: Pfn, count: usize) {
 		for i in 0..count {
-			self.free_pages.insert(Pfn(start.0 + i));
+			let pfn = Pfn(start.0 + i);
+			let phys_addr = PhysAddr(pfn.0 * 4096);
+
+			// Store current head in the new page
+			// We can write to phys_addr because it's identity mapped
+			unsafe {
+				let ptr = phys_addr.0 as *mut u64;
+				*ptr = self.free_list_head.map(|a| a.0 as u64).unwrap_or(0);
+			}
+
+			// Update head
+			self.free_list_head = Some(phys_addr);
 		}
 		self.total_pages += count;
+		self.free_count += count;
 	}
 
 	/// Allocate a single page
 	fn alloc_page(&mut self) -> Result<Pfn> {
-		if let Some(pfn) = self.free_pages.iter().next().copied() {
+		if let Some(head_addr) = self.free_list_head {
-			self.free_pages.remove(&pfn);
+			// Read next ptr from head
+			let next_addr_u64 = unsafe { *(head_addr.0 as *const u64) };
+
+			self.free_list_head = if next_addr_u64 == 0 {
+				None
+			} else {
+				Some(PhysAddr(next_addr_u64 as usize))
+			};
+
 			self.allocated_pages += 1;
-			Ok(pfn)
+			self.free_count -= 1;
+			Ok(Pfn(head_addr.0 / 4096))
 		} else {
 			Err(Error::OutOfMemory)
 		}
@@ -133,18 +155,19 @@ impl PageAllocator {
 
 	/// Free a single page
 	fn free_page(&mut self, pfn: Pfn) {
-		if self.free_pages.insert(pfn) {
+		let phys_addr = PhysAddr(pfn.0 * 4096);
-			self.allocated_pages -= 1;
+		unsafe {
+			let ptr = phys_addr.0 as *mut u64;
+			*ptr = self.free_list_head.map(|a| a.0 as u64).unwrap_or(0);
 		}
+		self.free_list_head = Some(phys_addr);
+		self.allocated_pages -= 1;
+		self.free_count += 1;
 	}
 
 	/// Get statistics
 	fn stats(&self) -> (usize, usize, usize) {
-		(
+		(self.total_pages, self.allocated_pages, self.free_count)
-			self.total_pages,
-			self.allocated_pages,
-			self.free_pages.len(),
-		)
 	}
 }
 

kernel/src/process.rs

@@ -251,6 +251,29 @@ impl ProcessTable {
 		}
 		None
 	}
+
+	pub fn find_two_threads_mut(
+		&mut self,
+		tid1: Tid,
+		tid2: Tid,
+	) -> (Option<&mut Thread>, Option<&mut Thread>) {
+		if tid1 == tid2 {
+			let t = self.find_thread_mut(tid1);
+			return (t, None);
+		}
+
+		// This is a bit inefficient but safe
+		// We can't easily return two mutable references to the same structure
+		// But since they are in different processes or different threads, they are distinct memory locations.
+		// We can use unsafe to cheat the borrow checker, knowing that tid1 != tid2.
+
+		let ptr = self as *mut ProcessTable;
+		unsafe {
+			let t1 = (*ptr).find_thread_mut(tid1);
+			let t2 = (*ptr).find_thread_mut(tid2);
+			(t1, t2)
+		}
+	}
 }
 
 /// Allocate a new PID
@@ -279,6 +302,20 @@ pub fn create_process(name: String, uid: Uid, gid: Gid) -> Result<Pid> {
 	Ok(pid)
 }
 
+/// Add a thread to the kernel process (PID 0)
+pub fn add_kernel_thread(tid: Tid, context: Context, stack_pointer: VirtAddr) -> Result<()> {
+	let mut table = PROCESS_TABLE.lock();
+	if let Some(process) = table.get_process_mut(Pid(0)) {
+		let mut thread = Thread::new(tid, Pid(0), 0);
+		thread.context = context;
+		thread.stack_pointer = stack_pointer;
+		process.add_thread(thread);
+		Ok(())
+	} else {
+		Err(Error::NotFound)
+	}
+}
+
 /// Get current process PID
 pub fn current_process_pid() -> Option<Pid> {
 	let table = PROCESS_TABLE.lock();

kernel/src/scheduler.rs

@@ -458,32 +458,39 @@ impl Scheduler {
 		if let Some(current_tid) = self.current {
 			if current_tid != tid {
 				// Look up current and next threads
-				let process_table = PROCESS_TABLE.lock();
+				// We need to use a scope to ensure the lock is dropped before switching
-				if let (Some(current_thread), Some(next_thread)) = (
+				let (current_ctx_ptr, next_ctx_ptr) = {
-					process_table.find_thread(current_tid),
+					let mut process_table = PROCESS_TABLE.lock();
-					process_table.find_thread(tid),
+
-				) {
+					let (current_thread, next_thread) = process_table
+						.find_two_threads_mut(current_tid, tid);
+
+					let current_ptr = if let Some(t) = current_thread {
+						&mut t.context as *mut Context
+					} else {
+						return; // Current thread not found?
+					};
+
+					let next_ptr = if let Some(t) = next_thread {
+						&t.context as *const Context
+					} else {
+						return; // Next thread not found
+					};
+
+					(current_ptr, next_ptr)
+				};
+
 				// Update scheduler state
 				self.current = Some(tid);
 				self.nr_switches += 1;
 
-					// Drop the lock before context switch to avoid deadlock
+				// Perform the context switch
-					drop(process_table);
+				// SAFETY: We have valid pointers to the contexts and we've dropped the lock
-
+				unsafe {
-					// TODO: Implement actual context switch
+					switch_context(&mut *current_ctx_ptr, &*next_ctx_ptr);
-					// This would involve:
-					// 1. Saving current thread's context
-					// 2. Loading next thread's context
-					// 3. Switching page tables if different processes
-					// 4. Updating stack pointer and instruction pointer
-
-					crate::info!(
-						"Context switch from TID {} to TID {}",
-						current_tid.0,
-						tid.0
-					);
-					return;
 				}
+
+				return;
 			}
 		}
 
@@ -654,3 +661,10 @@ pub fn scheduler_tick() {
 		}
 	}
 }
+
+/// Perform a manual context switch to a specific task
+/// This is used by the enhanced scheduler to execute its scheduling decisions
+pub fn context_switch_to(tid: Tid) {
+	let mut scheduler = SCHEDULER.lock();
+	scheduler.switch_to(tid);
+}

kernel/src/simple_boot.s

@@ -0,0 +1,41 @@
+# Simple multiboot2 header and boot code
+.section .multiboot_header, "a", @progbits
+.align 8
+
+multiboot2_header_start:
+    .long 0xe85250d6                # multiboot2 magic
+    .long 0                         # architecture (i386)
+    .long multiboot2_header_end - multiboot2_header_start  # header length
+    .long -(0xe85250d6 + 0 + (multiboot2_header_end - multiboot2_header_start))  # checksum
+
+    # End tag
+    .word 0    # type
+    .word 0    # flags  
+    .long 8    # size
+multiboot2_header_end:
+
+.section .text
+.global _start
+.code32
+
+_start:
+    # Disable interrupts
+    cli
+    
+    # Set up a simple stack
+    mov $stack_top, %esp
+    mov $stack_top, %ebp
+    
+    # Call main Rust function
+    call main
+    
+    # If main returns, halt
+halt:
+    hlt
+    jmp halt
+
+.section .bss
+.align 16
+stack_bottom:
+    .skip 16384  # 16KB stack
+stack_top:

kernel/src/sysinfo.rs

@@ -69,7 +69,7 @@ impl CpuInfo {
 			unsafe {
 				asm!("mov {ebx_save}, rbx",
                      "cpuid", 
-                     "mov {ebx_out}, ebx",
+                     "mov {ebx_out:e}, ebx",
                      "mov rbx, {ebx_save}",
                      ebx_save = out(reg) _,
                      ebx_out = out(reg) ebx,
@@ -144,7 +144,7 @@ impl CpuInfo {
 
 			asm!("mov {ebx_save}, rbx",
                  "cpuid", 
-                 "mov {ebx_out}, ebx",
+                 "mov {ebx_out:e}, ebx",
                  "mov rbx, {ebx_save}",
                  ebx_save = out(reg) _,
                  ebx_out = out(reg) vendor_ebx,

kernel/src/time.rs

@@ -403,8 +403,37 @@ impl TimerWheel {
 	}
 
 	pub fn add_timer(&mut self, timer: HrTimer) {
-		// TODO: Add timer to appropriate level based on expiry time
+		let now_ns = get_time_ns();
-		let level = 0; // Simplified
+		let expires_ns = timer.expires.to_ns();
+
+		// If already expired or expires very soon, put in level 0
+		if expires_ns <= now_ns {
+			self.levels[0].push(timer);
+			return;
+		}
+
+		let delta_ns = expires_ns - now_ns;
+		let delta_jiffies = delta_ns / NSEC_PER_JIFFY;
+
+		// Determine level based on delta
+		// Level 0: Immediate to ~256ms
+		// Level 1: ~256ms to ~16s
+		// Level 2: ~16s to ~17m
+		// Level 3: ~17m to ~18h
+		// Level 4+: Far future
+		let level = if delta_jiffies < 256 {
+			0
+		} else if delta_jiffies < 256 * 64 {
+			1
+		} else if delta_jiffies < 256 * 64 * 64 {
+			2
+		} else if delta_jiffies < 256 * 64 * 64 * 64 {
+			3
+		} else {
+			4
+		};
+
+		let level = core::cmp::min(level, 7);
 		self.levels[level].push(timer);
 	}
 

kernel/src/timer.rs

@@ -93,9 +93,10 @@ impl TimerState {
 					let mut stats = self.stats.lock();
 					stats.context_switches += 1;
 
-					// TODO: Actual context switching would happen here
+					// Perform actual context switch
-					// This would involve saving current CPU state and
+					// This will save current CPU state and restore the state of the next task
-					// restoring the state of the next task
+					crate::scheduler::context_switch_to(next_tid);
+
 					crate::info!(
 						"Context switch: {:?} -> {:?}",
 						current_tid,

kernel/src/working_task.rs

@@ -50,8 +50,8 @@ impl Task {
 		function: TaskFunction,
 		stack_size: usize,
 	) -> Result<Self> {
-		static NEXT_TID: AtomicU32 = AtomicU32::new(1);
+		// Use process subsystem to allocate TID to ensure uniqueness
-		let tid = Tid(NEXT_TID.fetch_add(1, Ordering::Relaxed));
+		let tid = crate::process::allocate_tid();
 
 		// Allocate stack
 		let stack_ptr = kmalloc::kmalloc(stack_size)?;
@@ -156,10 +156,18 @@ impl TaskManager {
 		function: TaskFunction,
 		stack_size: usize,
 	) -> Result<Tid> {
-		let task = Task::new_kernel_task(name, function, stack_size)?;
+		let task = Task::new_kernel_task(name.clone(), function, stack_size)?;
 		let tid = task.tid;
 
-		self.tasks.lock().push(task);
+		// Add to local task list
+		self.tasks.lock().push(task.clone());
+
+		// Add to PROCESS_TABLE so the low-level scheduler can find it
+		crate::process::add_kernel_thread(
+			tid,
+			task.context,
+			crate::memory::VirtAddr::new(task.context.rsp as usize),
+		)?;
 
 		// Add to enhanced scheduler
 		crate::enhanced_scheduler::add_task(

src/lib.rs

@@ -1,24 +1,17 @@
 // SPDX-License-Identifier: GPL-2.0
 
-//! Rust Kernel
+//! Rust Kernel Library
 //!
 //! A modern kernel implementation in Rust, inspired by the Linux kernel
 //! and utilizing the Rust for Linux infrastructure.
 
 #![no_std]
-#![no_main]
 
 extern crate kernel;
 
 // Re-export the kernel crate
 pub use kernel::*;
 
-/// Main kernel entry point
-#[no_mangle]
-pub extern "C" fn _start() -> ! {
-	kernel::kernel_main()
-}
-
 #[cfg(test)]
 mod tests {
 	#[test]

src/main.rs

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust Kernel Binary
+//!
+//! Main binary entry point for the Rust kernel
+
+#![no_std]
+#![no_main]
+
+extern crate kernel;
+
+use core::arch::global_asm;
+
+// Include boot assembly
+#[cfg(target_arch = "x86_64")]
+global_asm!(
+	include_str!("../kernel/src/arch/x86_64/boot.s"),
+	options(att_syntax)
+);