cleaning up before kmalloc

README.md

@@ -1,36 +1,33 @@
-## hobby kernel in zig
-
-slowly porting from rust.
+# hobby kernel in zig
 
 ### features
 
- - vga frame buffer
+ - 80x25 frame buffer
  - ps2 keyboard driver
- - interrupts
  - terminal console
  - lspci
+ - x86
+   - MMU
+   - interrupts
 
 ### dependencies
 
-`zig` compiler
+  - [ziglang](https://github.com/ziglang/zig) 0.5.0
 
-### compile
+# How to
 
-`zig build` compiles and links the multiboot kernel, without a bootloader.
+## compile
 
-### test
+`zig build` compiles and links the multiboot kernel (without a bootloader)
 
-`./qemu.sh start`  
-`./qemu.sh monitor`  
-`./qemu.sh gdb`  
+## test
+
+ - `./qemu.sh start`
+ - `./qemu.sh monitor`
+ - `./qemu.sh gdb`
 
 # Notes
 
-## interrupts
+## interrupt call chain
 
 `interrupt` -> `idt[n]` -> `isrN` -> `isrDispatch` -> `handlers[n]` (default `unhandled()`)
-
-## layout
-
-`0->4Mib` kernel reserved
-`1Mib` interrupt stack

qemu.sh

@@ -18,7 +18,7 @@ start() {
         # -device virtio-net,netdev=network0 -netdev tap,id=network0,ifname=tap0,script=no,downscript=no \
 	# build/kernel.iso
 
-        # this allows this switch to monitor with ^a-c, but doesn't
+        # this allows to monitor with ^a-c, but doesn't
         # play nice with irqs apparently...
         # -serial mon:stdio \
 }

src/arch/x86/idt.zig

@@ -58,6 +58,7 @@ pub fn initialize() void {
     isr.install_irqs();
     isr.install_syscalls();
     interrupt.registerIRQ(0, interrupt.pit_handler);
+    interrupt.registerIRQ(1, ps2.keyboard_handler);
 
     // load IDT
     lidt(@ptrToInt(&idtr));

src/arch/x86/index.zig

@@ -1,16 +1,20 @@
+// std
+pub const assert = @import("std").debug.assert;
+
+// from core kernel
 pub usingnamespace @import("../../vga.zig");
 pub const multiboot = @import("../../multiboot.zig");
 pub const time = @import("../../time.zig");
+pub const ps2 = @import("../../ps2.zig");
 
+// x86 namespace
 pub usingnamespace @import("lib/io.zig");
 pub usingnamespace @import("lib/instructions.zig");
 pub usingnamespace @import("main.zig");
-
+pub const layout = @import("layout.zig");
 pub const memory = @import("memory.zig");
 pub const paging = @import("paging.zig");
 pub const idt = @import("idt.zig");
 pub const isr = @import("isr.zig");
 pub const gdt = @import("gdt.zig");
 pub const interrupt = @import("interrupt.zig");
-
-pub const assert = @import("std").debug.assert;

src/arch/x86/interrupt.zig

@@ -175,11 +175,8 @@ pub fn maskIRQ(irq: u8, mask: bool) void {
 
     // Mask or unmask the interrupt.
     const shift = @intCast(u3, irq % 8);
-    if (mask) {
-        outb(port, old | (u8(1) << shift));
-    } else {
-        outb(port, old & ~(u8(1) << shift));
-    }
+    if (mask) outb(port, old | (u8(1) << shift));
+    if (!mask) outb(port, old & ~(u8(1) << shift));
     const new = inb(port); // Retrieve the current mask.
 }
 

src/arch/x86/layout.zig

@@ -1,6 +1,15 @@
 //https://wiki.osdev.org/Memory_Map_(x86)
 
+const kiB = 1024;
+const MiB = 1024 * kiB; // 0x100000
+const GiB = 1024 * MiB;
+
+// zig fmt: off
 pub const KSTACK            = 0x80000; // todo: move to .bss
-pub const KERNEL = 0x100000;
-pub const IDENTITY = 0x400000; // 0->4MiB
-pub const HEAP = 0x800000;
+pub const KERNEL            = 1 * MiB;
+pub const IDENTITY          = 4 * MiB; // 0->4MiB
+
+pub const HEAP              = 8 * MiB;
+pub const USER_STACKS       = 0x1000000;
+pub const USER_STACKS_END   = 0x10000000;
+// zig fmt: on

src/arch/x86/memory.zig

@@ -8,27 +8,31 @@ pub var stack_size: usize = undefined;
 pub var stack_end: usize = undefined;
 
 pub const PAGE_SIZE: usize = 4096;
+pub inline fn pageAlign(address: u32) u32 {
     // 4095 -> 4096
     // 4096 -> 4096
     // 4097 -> 8192
-pub fn pageAlign(address: u32) u32 {
     return (address + PAGE_SIZE - 1) & (~PAGE_SIZE +% 1);
 }
 
 ////
 // Return the amount of variable elements (in bytes).
 //
-pub fn available() usize {
+pub inline fn available() usize {
     return stack_index * PAGE_SIZE;
 }
 
+pub inline fn available_MiB() usize {
+    return available() / (1024 * 1024);
+}
+
 ////
 // Request a free physical page and return its address.
 //
-pub fn allocate() ?usize {
+pub fn allocate() !usize {
     if (available() == 0) {
         println("out of memory");
-        return null;
+        return error.OutOfMemory;
     }
     stack_index -= 1;
     return stack[stack_index];
@@ -56,9 +60,14 @@ pub fn initialize(info: *const multiboot.MultibootInfo) void {
     assert((info.flags & multiboot.MULTIBOOT_INFO_MEMORY) != 0);
     assert((info.flags & multiboot.MULTIBOOT_INFO_MEM_MAP) != 0);
 
+    // TODO: WHAT WHY WHAAAAT, must check back here later
+    // Place stack at 0x200000 so that in the future I trigger a
+    // random bug and I won't ever know where it came from, great.
+    stack = @intToPtr([*]usize, 0x200000); // 2 MiB
+
     // Place the stack of free pages after the last Multiboot module.
-    stack = @intToPtr([*]usize, 0x200000);
     // stack = @intToPtr([*]usize, pageAlign(info.mods_addr));
+
     // Calculate the approximate size of the stack based on the amount of total upper memory.
     stack_size = ((info.mem_upper * 1024) / PAGE_SIZE) * @sizeOf(usize);
     stack_end = pageAlign(@ptrToInt(stack) + stack_size);
@@ -83,3 +92,7 @@ pub fn initialize(info: *const multiboot.MultibootInfo) void {
 
     println("available memory: {d} MiB ", available() / 1024 / 1024);
 }
+
+pub fn introspect() void {
+    println("physframes left: {d} ({d} MiB)", stack_index, available_MiB());
+}

src/arch/x86/paging.zig

@@ -22,13 +22,13 @@ fn pageFault() void {
     while (true) asm volatile ("hlt");
 }
 
-fn pageBase(addr: usize) usize {
+inline fn pageBase(addr: usize) usize {
     return addr & (~PAGE_SIZE +% 1);
 }
-fn pde(addr: usize) *PageEntry {
+inline fn pde(addr: usize) *PageEntry {
     return &PD[addr >> 22];
 }
-fn pte(addr: usize) *PageEntry {
+inline fn pte(addr: usize) *PageEntry {
     return &PT[addr >> 12];
 }
 
@@ -46,14 +46,28 @@ pub fn unmap(virt: usize) void {
     }
 }
 
-pub fn mmap(virt: usize, phys: ?usize) void {
+pub fn mmap(virt: usize, phys: ?usize) !void {
     var pde: *PageEntry = pde(virt);
-    if (pde.* == 0) pde.* = memory.allocate() | WRITE | PRESENT;
+    if (pde.* == 0) pde.* = try memory.allocate() | WRITE | PRESENT;
     var pte: *PageEntry = pte(virt);
     pte.* = if (phys) |p| p else allocate() | PRESENT;
 }
 
-pub fn addrspace() void {
+pub fn initialize() void {
+    var p2 = pageDirectory[0..];
+
+    // identity map 0 -> 4MB
+    p2[0] = 0x000000 | PRESENT | WRITE | HUGE;
+    // recursive mapping
+    p2[1023] = @ptrToInt(&p2[0]) | PRESENT | WRITE;
+
+    assert(memory.stack_end < layout.IDENTITY);
+
+    interrupt.register(14, pageFault);
+    setupPaging(@ptrToInt(&pageDirectory[0]));
+}
+
+pub fn introspect() void {
     var i: usize = 1;
     i = 0;
     while (i < 1024) : (i += 1) {
@@ -67,17 +81,3 @@ pub fn addrspace() void {
         }
     }
 }
-
-pub fn initialize() void {
-    var p2 = pageDirectory[0..];
-
-    // identity map 0 -> 4MB
-    p2[0] = 0x000000 | PRESENT | WRITE | HUGE;
-    // recursive mapping
-    p2[1023] = @ptrToInt(&p2[0]) | PRESENT | WRITE;
-
-    assert(memory.stack_end < 0x400000);
-
-    interrupt.register(14, pageFault);
-    setupPaging(@ptrToInt(&pageDirectory[0]));
-}

src/console.zig

@@ -4,10 +4,13 @@ var command: [10]u8 = undefined;
 var command_len: usize = 0;
 
 fn execute(com: []u8) void {
-    if (@import("std").mem.eql(u8, com, "lspci")) pci.lspci();
-    if (@import("std").mem.eql(u8, com, "paging")) x86.paging.addrspace();
-    if (@import("std").mem.eql(u8, com, "uptime")) time.uptime();
-    if (@import("std").mem.eql(u8, com, "topbar")) topbar();
+    const eql = std.mem.eql;
+    if (eql(u8, com, "x86paging")) return x86.paging.introspect();
+    if (eql(u8, com, "x86memory")) return x86.memory.introspect();
+    if (eql(u8, com, "lspci")) return pci.lspci();
+    if (eql(u8, com, "uptime")) return time.uptime();
+    if (eql(u8, com, "topbar")) return topbar();
+    println("{}: command not found", com);
 }
 
 pub fn keypress(char: u8) void {
@@ -15,7 +18,7 @@ pub fn keypress(char: u8) void {
     switch (char) {
         '\n' => {
             print("\n");
-            execute(command[0..command_len]);
+            if (command_len > 0) execute(command[0..command_len]);
             print("> ");
             command_len = 0;
         },
@@ -38,6 +41,6 @@ pub fn keypress(char: u8) void {
 }
 
 pub fn initialize() void {
-    x86.interrupt.registerIRQ(1, ps2.keyboard_handler);
+    ps2.keyboard_callback = keypress;
     print("> ");
 }

src/index.zig

@@ -1,10 +1,14 @@
-pub const assert = @import("std").debug.assert;
+// std
 pub const std = @import("std");
+pub const assert = std.debug.assert;
 
+// main namespace
 pub usingnamespace @import("vga.zig");
+pub const x86 = @import("arch/x86/index.zig");
 pub const multiboot = @import("multiboot.zig");
+pub const mem = @import("memory.zig");
+pub const task = @import("task.zig");
 pub const console = @import("console.zig");
 pub const pci = @import("pci/pci.zig");
 pub const ps2 = @import("ps2.zig");
-pub const x86 = @import("arch/x86/index.zig");
 pub const time = @import("time.zig");

src/main.zig

@@ -26,5 +26,7 @@ export fn kmain(magic: u32, info: *const multiboot.MultibootInfo) noreturn {
     pci.scan();
     console.initialize();
 
+    // const t = task.Task.new(@ptrToInt(topbar));
+
     while (true) asm volatile ("hlt");
 }

src/memory.zig

@@ -1,8 +1,7 @@
-const paging = @import("arch/x86/paging.zig");
+pub usingnamespace @import("index.zig");
 
-pub fn alloc(size: usize) usize {
+pub fn allocate(comptime T: type) !*type {}
 
-}
+pub fn free(address: usize) void {}
 
-pub fn free() {
-}
+pub fn initialize() void {}

src/pci/pci.zig

@@ -54,9 +54,11 @@ pub const PciDevice = struct {
             var drv = Drivers[i];
             if (self.class() != drv.class or self.subclass() != drv.subclass)
                 continue;
-            if (drv.vendor) |v| if (self.vendor != v)
+            if (drv.vendor) |v|
+                if (self.vendor != v)
                     continue;
-            if (drv.subsystem) |ss| if (self.subsystem() != ss)
+            if (drv.subsystem) |ss|
+                if (self.subsystem() != ss)
                     continue;
             return drv;
         }

src/ps2.zig

@@ -78,9 +78,13 @@ fn key_isrelease(scancode: u8) bool {
     return scancode & (1 << 7) != 0;
 }
 
+pub var keyboard_callback: fn (u8) void = undefined;
+
 pub fn keyboard_handler() void {
     const scancode = ps2_scancode();
+    if (scancode > KEYMAP_US.len) return;
     if (key_isrelease(scancode)) return; // don't process releases
     const shift = false; // don't know about modifiers yet
-    console.keypress(KEYMAP_US[scancode][if (shift) 1 else 0]);
+    const character = KEYMAP_US[scancode][if (shift) 1 else 0];
+    if (keyboard_callback != undefined) keyboard_callback(character);
 }

src/time.zig

@@ -10,5 +10,5 @@ pub fn increment(value: u32) void {
 
 pub fn uptime() void {
     const offset_ms = offset_us / 1000;
-    println("uptime: {}.{:.3}", offset_s, offset_ms);
+    println("{}.{:.3}", offset_s, offset_ms);
 }

src/vga.zig

@@ -2,7 +2,6 @@
 const time = @import("time.zig");
 const x86 = @import("arch/x86/index.zig");
 const std = @import("std");
-
 // Screen size.
 pub const VGA_WIDTH = 80;
 pub const VGA_HEIGHT = 25;
@@ -70,8 +69,7 @@ pub fn topbar() void {
     vga.cursor = 0;
     vga.background = Color.Red;
 
-    const offset_ms = time.offset_us / 1000;
-    println("{}.{}", time.offset_s, offset_ms / 10);
+    time.uptime();
 
     vga.cursor = cursor;
     vga.background = bg;
@@ -154,10 +152,12 @@ const VGA = struct {
     //
     fn scrollDown(self: *VGA) void {
         const first = VGA_WIDTH; // Index of first line.
+        const second = 2 * VGA_WIDTH; // Index of first line.
         const last = VGA_SIZE - VGA_WIDTH; // Index of last line.
 
         // Copy all the screen (apart from the first line) up one line.
-        std.mem.copy(VGAEntry, self.vram[0..last], self.vram[first..VGA_SIZE]);
+        // std.mem.copy(VGAEntry, self.vram[0..last], self.vram[first .. VGA_SIZE]); // whole screen
+        std.mem.copy(VGAEntry, self.vram[first..last], self.vram[second..VGA_SIZE]); // skip topbar
         // Clean the last line.
         std.mem.set(VGAEntry, self.vram[last..VGA_SIZE], self.entry(' '));