KaiNorberg · KaiNorberg · Jan 14, 2026 · Jan 13, 2026 · Jan 13, 2026 · Jan 13, 2026
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
@@ -14,30 +14,36 @@ jobs:
     - name: Checkout repository
       uses: actions/checkout@v4
       with:
-        submodules: trues
+        submodules: true
 
     - name: Install build dependencies
       run: |
         sudo apt-get update
-        sudo apt-get install -y build-essential qemu-system-x86 mtools iasl
-
-    - name: Setup PatchworkOS
-      run: make setup DEBUG=1 TESTING=1 QEMU_EXIT_ON_PANIC=1
+        sudo apt-get install -y clang llvm build-essential qemu-system-x86 mtools iasl
 
     - name: Build PatchworkOS
       run: make all DEBUG=1 TESTING=1 QEMU_EXIT_ON_PANIC=1
 
+    - name: Inspect kernel ELF
+      run: |
+        echo "=== Kernel ELF Program Headers ==="
+        readelf -l bin/kernel/kernel || true
+        echo "=== Kernel ELF Section Headers ==="
+        readelf -S bin/kernel/kernel || true
+        echo "=== Kernel file size ==="
+        ls -la bin/kernel/kernel
+
     - name: Verify PatchworkOS.img exists
       run: |
         if [ ! -f bin/PatchworkOS.img ]; then
           echo "Error: bin/PatchworkOS.img not found after build!"
           exit 1
         fi
 
-    - name: Run PatchworkOS with QEMU (test launch and graceful timeout)
+    - name: Run PatchworkOS with QEMU
       id: qemu_test
-      run: | # We use this cheap trick to check if qemu runs properly, the idea is that we start qemu, and let it run for one minute and it does not crash thats considered a success, if it crashes, well thats bad. If it doesent we shut it down and call it a success, a bit simple but gets the job done.
-        setsid make run DEBUG=1 TESTING=1 QEMU_EXIT_ON_PANIC=1 &
+      run: |
+        setsid make run DEBUG=1 TESTING=1 QEMU_EXIT_ON_PANIC=1 QEMU_NOGRAPHIC=1 &
         QEMU_PID=$!
         echo "QEMU process started with PID=$QEMU_PID"
         echo "QEMU_PID=$QEMU_PID" >> $GITHUB_OUTPUT

diff --git a/.gitignore b/.gitignore
@@ -69,5 +69,6 @@ include/kernel/version.h
 lib/acpica
 lib/acpica_tests
 lib/argon2
+lib/gnu-efi
 include/argon2
 temp.md
diff --git a/Make.defaults b/Make.defaults
@@ -3,14 +3,16 @@ MKCWD = @mkdir -p $(@D)
 CC = gcc
 AS = gcc
 LD = gcc
-AR = gcc-ar
+AR = ar
 OBJCOPY = objcopy
-
 CFLAGS := \
 	-std=gnu11 \
 	-ffreestanding \
 	-fno-builtin \
+	-march=x86-64 \
 	-fno-pie \
+	-fno-stack-protector \
+	-fcf-protection=none \
 	-mno-red-zone \
 	-nostdinc \
 	-Wall \
@@ -36,7 +38,8 @@ CFLAGS_DISABLE_SIMD := \
 	-mno-mmx -mno-3dnow \
 	-mno-80387 -mno-sse \
 	-mno-sse2 -mno-sse3 \
-	-mno-ssse3 -mno-sse4
+	-mno-ssse3 -mno-sse4 \
+	-mno-avx -mno-avx2
 
 ASFLAGS := \
 	-nostdinc \
@@ -51,7 +54,9 @@ LDFLAGS := \
 	-nostdlib \
 	-Lbin/libstd \
 	-Lbin/libpatchwork \
-	-no-pie
+	-z noexecstack \
+	-Wno-unused-command-line-argument \
+	-no-pie 
 
 ifeq ($(TESTING),1)
 	CFLAGS += -D_TESTING_
@@ -61,10 +66,8 @@ endif
 ifeq ($(DEBUG),1)
 	CFLAGS += -O0 -g3 -ggdb -fno-omit-frame-pointer -fno-inline
 	LDFLAGS += -g
-	DEBUG_LDFLAGS = -g
 else
 	CFLAGS += -O2 -DNDEBUG
-	DEBUG_LDFLAGS =
 endif
 
 ifeq ($(NOSTDLIB),1)

diff --git a/Make.rules b/Make.rules
@@ -16,40 +16,4 @@ $(BINDIR)/%.a: $(OBJ)
 $(BINDIR)/%: $(OBJ)
 	$(MKCWD)
 	@echo "  LD    $@"
-	@$(LD) -o $@ $^ $(LDFLAGS) $(LDSTDLIB)
-
-$(BINDIR)/%.efi: $(OBJ)
-	$(MKCWD)
-	@echo "  LD    $@ (EFI)"
-	@gcc -shared -nostdlib -nostartfiles -fPIC -fno-stack-protector \
-		$(DEBUG_LDFLAGS) \
-		-Wl,-shared,-Bsymbolic \
-		-Wl,-T,lib/gnu-efi/gnuefi/elf_x86_64_efi.lds \
-		-Llib/gnu-efi/x86_64/lib \
-		-Llib/gnu-efi/x86_64/gnuefi \
-		lib/gnu-efi/x86_64/gnuefi/crt0-efi-x86_64.o $^ \
-		-o $(BINDIR)/temp.so \
-		-lgnuefi -lefi
-
-ifeq ($(DEBUG),1)
-	@echo "  OBJCOPY $@ (with debug symbols)"
-	@$(OBJCOPY) --only-keep-debug $(BINDIR)/temp.so $(BINDIR)/$*.debug
-	@$(OBJCOPY) \
-		-j .text -j .sdata -j .data -j .dynamic -j .dynsym \
-		-j .rel -j .rela -j .rel.* -j .rela.* -j .reloc -j .eh_frame \
-		--target efi-app-x86_64 \
-		--subsystem=10 \
-		--add-gnu-debuglink=$(BINDIR)/$*.debug \
-		$(BINDIR)/temp.so $@
-	@$(OBJCOPY) --strip-debug $@
-else
-	@echo "  OBJCOPY $@"
-	@$(OBJCOPY) \
-		-j .text -j .sdata -j .data -j .dynamic -j .dynsym \
-		-j .rel -j .rela -j .rel.* -j .rela.* -j .reloc -j .eh_frame \
-		--target efi-app-x86_64 \
-		--subsystem=10 \
-		$(BINDIR)/temp.so $@
-endif
-
-	@rm -f $(BINDIR)/temp.so
+	@$(LD) -o $@ $^ $(LDFLAGS) $(LDSTDLIB)
diff --git a/Makefile b/Makefile
@@ -90,7 +90,11 @@ $(VERSION_HEADER): .FORCE | include/kernel
 include/kernel:
 	@mkdir -p $@
 
-lib/gnu-efi/.built: | lib/gnu-efi
+lib/gnu-efi/.built:
+	@if [ ! -d "lib/gnu-efi" ]; then \
+		echo "CLONE   gnu-efi"; \
+		git clone https://github.com/ncroxon/gnu-efi.git lib/gnu-efi >/dev/null 2>&1; \
+	fi
 	@echo "BUILD   gnu-efi"
 	@$(MAKE) -C lib/gnu-efi >/dev/null 2>&1
 	@touch $@
@@ -248,9 +252,7 @@ clean_programs:
 
 nuke: clean
 	@echo "NUKE    all"
-	@$(MAKE) -C lib/gnu-efi clean 2>/dev/null || true
-	@rm -rf lib/doomgeneric-patchworkos lib/lua-5.4.7 lib/acpica lib/acpica_tests lib/argon2 include/argon2 meta/docs
-	@rm -rf lib/gnu-efi/.built lib/argon2/.built lib/acpica_tests/.built
+	@rm -rf lib/doomgeneric lib/lua lib/acpica lib/acpica_tests lib/argon2 include/argon2 meta/docs lib/gnu-efi 
 
 QEMU_MEMORY ?= 2G
 QEMU_CPUS ?= $(shell nproc 2>/dev/null || echo 8)
@@ -259,15 +261,19 @@ QEMU_ARGS ?=
 
 QEMU_FLAGS = \
 	-M $(QEMU_MACHINE) \
-	-display sdl \
-	-serial stdio \
 	-drive format=raw,file=$(IMAGE) \
 	-m $(QEMU_MEMORY) \
 	-smp $(QEMU_CPUS) \
 	-cpu qemu64 \
 	-drive if=pflash,format=raw,unit=0,file=lib/OVMFbin/OVMF_CODE-pure-efi.fd,readonly=on \
 	-drive if=pflash,format=raw,unit=1,file=lib/OVMFbin/OVMF_VARS-pure-efi.fd
 
+ifeq ($(QEMU_NOGRAPHIC),1)
+QEMU_FLAGS += -nographic
+else
+QEMU_FLAGS += -display sdl -serial stdio
+endif
+
 ifeq ($(DEBUG),1)
 else
 QEMU_FLAGS += -no-shutdown -no-reboot

diff --git a/README.md b/README.md
@@ -24,9 +24,9 @@
 
 <img src="meta/screenshots/desktop.png" alt="Desktop Screenshot" />
 
-**PatchworkOS** is a modular non-POSIX operating system for the x86_64 architecture that rigorously follows an "everything is a file" philosophy, in the style of Plan9. Built from scratch in C and assembly, it's intended to be an educational and experimental operating system.
+**PatchworkOS** is a modular non-POSIX operating system for the x86_64 architecture that rigorously follows an "everything is a file" philosophy. Built from scratch in C and assembly.
 
-While primarily a project made for fun, the goal is still to make a "real" operating system, one that runs on real hardware and has the performance one would expect from a modern operating system without jumping ahead to user space features or drivers, a floppy disk driver and a round-robin scheduler are not enough.
+While primarily a project made for fun, the goal is still to make a "real" operating system, one that runs on real hardware and has the performance one would expect from a modern operating system without jumping ahead to user space features or drivers, a floppy disk driver with a round-robin scheduler is not enough.
 
 PatchworkOS is not a UNIX clone, it's intended to be a (hopefully) interesting experiment in operating system design by attempting to use unique algorithms and designs over tried and tested ones. Sometimes this leads to bad results, and sometimes, with a bit of luck, good ones.
 
@@ -55,7 +55,7 @@ Will this project ever reach its goals? Probably not, but that's not the point.
 
 - Preemptive and tickless [EEVDF scheduler](https://kainorberg.github.io/PatchworkOS/html/d7/d85/group__kernel__sched.html) based upon the [original paper](https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=805acf7726282721504c8f00575d91ebfd750564) and implemented using an [Augmented Red-Black tree](https://kainorberg.github.io/PatchworkOS/html/da/d90/group__kernel__utils__rbtree.html) to achieve `O(log n)` worst case complexity. EEVDF is the same algorithm used in the modern Linux kernel, but ours is obviously **a lot** less mature.
 - Multithreading and Symmetric Multi Processing with fine-grained locking.
-- Physical and virtual memory management is `O(1)` per page and `O(n)` where `n` is the number of pages per allocation/mapping operation, see [benchmarks](#benchmarks) for more info.
+- Optimized memory management, featuring object caching and `O(1)` per page physical and virtual memory managers. See [benchmarks](#benchmarks) for more info.
 - File based IPC including [pipes](https://kainorberg.github.io/PatchworkOS/html/d7/d64/group__modules__ipc__pipe.html), [shared memory](https://kainorberg.github.io/PatchworkOS/html/df/d3f/group__modules__ipc__shmem.html), [sockets](https://kainorberg.github.io/PatchworkOS/html/d4/db0/group__kernel__fs__netfs.html) and Plan9 inspired "signals" called [notes](https://kainorberg.github.io/PatchworkOS/html/d8/db1/group__kernel__ipc__note.html).
 - File based device API [abstractions](https://kainorberg.github.io/PatchworkOS/html/de/d7b/group__kernel__drivers__abstract.html), including framebuffers, input devices, etc.
 - [Synchronization primitives](https://kainorberg.github.io/PatchworkOS/html/dd/d6b/group__kernel__sync.html) including Read-Copy-Update, mutexes, R/W locks, sequential locks, futexes and others.
@@ -92,6 +92,24 @@ Will this project ever reach its goals? Probably not, but that's not the point.
 - Fully Asynchronous I/O and syscalls (io_uring?).
 - USB support.
 
+## Setup
+
+```bash
+# Install dependencies
+sudo dnf install gcc make mtools qemu-system-x86 # For Fedora
+sudo apt install build-essential mtools qemu-system-x86 # For Debian/Ubuntu
+
+# Clone this repository, you can also use the green Code button at the top of the Github.
+git clone https://github.com/KaiNorberg/PatchworkOS
+cd PatchworkOS
+
+# Build (creates PatchworkOS.img in bin/)
+make all
+
+# Run using QEMU
+make run
+```
+
 ---
 
 ## Doxygen Documentation
@@ -635,7 +653,9 @@ The scheduler has not yet been properly benchmarked. However, testing using the
 
 ## Shell Utilities
 
-PatchworkOS includes its own shell utilities designed around its [file flags](#file-flags) system, when file flags are used we also demonstrate the short form. Included is a brief overview with some usage examples. For convenience the shell utilities are named after their POSIX counterparts, however they are not drop-in replacements.
+PatchworkOS includes its own shell utilities designed around its [file flags](#file-flags) system, allowing all shell utilities to be "dumb" and rely on the virtual file system to provide more complex behavior.
+
+Included is a brief overview with some usage examples. For convenience the shell utilities are named after their POSIX counterparts, however they are not drop-in replacements. When file flags are used we also demonstrate the short form.
 
 ### touch
 
@@ -734,28 +754,7 @@ There are other utils available that work as expected, for example `symlink` and
 
 ---
 
-## Setup
-
-### Requirements
-
-| Requirement | Details |
-|:------------|:--------|
-| **OS** | Linux (WSL might work, but I make no guarantees) |
-| **Tools** | GCC, make, mtools, QEMU (optional) |
-
-### Build and Run
-
-```bash
-# Clone this repository, you can also use the green Code button at the top of the Github.
-git clone https://github.com/KaiNorberg/PatchworkOS
-cd PatchworkOS
-
-# Build (creates PatchworkOS.img in bin/)
-make all
-
-# Run using QEMU
-make run
-```
+## Development
 
 ### Additional commands
 
@@ -855,6 +854,10 @@ If you are unsure where to start, check the [Todo List](https://kainorberg.githu
 
 Check out the [contribution guidelines](CONTRIBUTING.md) to get started.
 
+## License
+
+Distributed under the MIT License. See [LICENSE](https://github.com/KaiNorberg/PatchworkOS/blob/main/LICENSE) for more information.
+
 ## Nostalgia
 
 [The first Reddit post and image of PatchworkOS](https://www.reddit.com/r/osdev/comments/18gbsng/a_little_over_2_years_ago_i_posted_a_screenshot/) from back when getting to user space was a massive milestone and the kernel was supposed to be a UNIX-like microkernel.
diff --git a/include/boot/boot_info.h b/include/boot/boot_info.h
@@ -3,11 +3,11 @@
 #include <kernel/mem/paging_types.h>
 
 #include <gnu-efi/inc/efi.h>
-#include <gnu-efi/inc/efilib.h>
 
+#include <_internal/MAX_NAME.h>
 #include <stdint.h>
+#include <sys/defs.h>
 #include <sys/elf.h>
-#include <sys/io.h>
 #include <sys/list.h>
 
 /**
@@ -21,7 +21,7 @@
  * @{
  */
 
-static bool boot_is_mem_ram(EFI_MEMORY_TYPE type)
+static UNUSED_FUNC bool boot_is_mem_ram(EFI_MEMORY_TYPE type)
 {
     switch (type)
     {

diff --git a/include/kernel/cpu/cli.h b/include/kernel/cpu/cli.h
@@ -24,7 +24,7 @@
 static inline void cli_push(void)
 {
     uint64_t rflags = rflags_read();
-    asm volatile("cli" ::: "memory");
+    ASM("cli" :: : "memory");
 
     if (SELF->cli == 0)
     {
@@ -46,7 +46,7 @@ static inline void cli_pop(void)
     SELF->cli--;
     if (SELF->cli == 0 && (SELF->oldRflags & RFLAGS_INTERRUPT_ENABLE))
     {
-        asm volatile("sti" ::: "memory");
+        ASM("sti" :: : "memory");
     }
 }
 

diff --git a/include/kernel/cpu/cpu.h b/include/kernel/cpu/cpu.h
@@ -2,7 +2,6 @@
 
 #ifndef __ASSEMBLER__
 #include <kernel/config.h>
-#include <kernel/cpu/cpu_id.h>
 #include <kernel/cpu/stack_pointer.h>
 #include <kernel/cpu/tss.h>
 
@@ -38,6 +37,33 @@ typedef struct cpu cpu_t;
 
 #ifndef __ASSEMBLER__
 
+/**
+ * @brief The offset of the `id` member in the `cpu_t` structure.
+ *
+ * Needed to access the CPU ID from assembly code.
+ */
+#define CPU_OFFSET_ID 0x8
+
+/**
+ * @brief Maximum number of CPUs supported.
+ */
+#define CPU_MAX UINT8_MAX
+
+/**
+ * @brief ID of the bootstrap CPU.
+ */
+#define CPU_ID_BOOTSTRAP 0
+
+/**
+ * @brief Invalid CPU ID.
+ */
+#define CPU_ID_INVALID UINT16_MAX
+
+/**
+ * @brief Type used to identify a CPU.
+ */
+typedef uint16_t cpu_id_t;
+
 /**
  * @brief CPU stack canary value.
  *
@@ -72,7 +98,7 @@ typedef struct cpu
     uint8_t doubleFaultStackBuffer[CONFIG_INTERRUPT_STACK_PAGES * PAGE_SIZE] ALIGNED(PAGE_SIZE);
     uint8_t nmiStackBuffer[CONFIG_INTERRUPT_STACK_PAGES * PAGE_SIZE] ALIGNED(PAGE_SIZE);
     uint8_t interruptStackBuffer[CONFIG_INTERRUPT_STACK_PAGES * PAGE_SIZE] ALIGNED(PAGE_SIZE);
-    uint8_t percpu[CONFIG_PERCPU_SIZE] ALIGNED(PAGE_SIZE);
+    uint8_t percpu[CONFIG_PERCPU_SIZE] ALIGNED(PAGE_SIZE); ///< Buffer used for per-CPU data.
 } cpu_t;
 
 static_assert(offsetof(cpu_t, self) == CPU_OFFSET_SELF,