add support for multiboot2

the bump allocator isn't ported
qemu -kernel doesn't support this

build.zig

@@ -2,7 +2,7 @@ const Builder = @import("std").build.Builder;
 const builtin = @import("builtin");
 
 pub fn build(b: *Builder) void {
-    const kernel = b.addExecutable("bzImage", "src/arch/x86/main.zig");
+    const kernel = b.addExecutable("kernel", "src/arch/x86/main.zig");
     kernel.addPackagePath("kernel", "src/index.zig");
     kernel.addPackagePath("arch", "src/arch/x86/lib/index.zig");
     kernel.setOutputDir("build");

grub.sh

@@ -5,6 +5,16 @@ exit_missing() {
 
 which xorriso || exit_missing
 which grub-mkrescue || exit_missing
-mkdir -p build/iso/boot
-cp build/bzImage build/iso/boot
+mkdir -p build/iso/boot/grub
+cp build/kernel build/iso/boot
+>build/iso/boot/grub/grub.cfg <<EOF
+set timeout=0
+set default=0
+
+menuentry "OS" {
+    multiboot2 /boot/kernel
+    boot
+}
+EOF
+
 grub-mkrescue -o build/kernel.iso build/iso

qemu.sh

@@ -1,30 +1,27 @@
 QEMU_SOCKET=/tmp/qemu.sock
 QEMU_MONITOR="socat - UNIX-CONNECT:${QEMU_SOCKET}"
 QEMU_GDB_PORT=4242
-KERNEL=build/bzImage
+KERNEL=build/kernel
 
 start() {
-    sudo pkill -9 qemu
     sudo qemu-system-i386 \
         -gdb tcp::${QEMU_GDB_PORT} \
         -monitor unix:${QEMU_SOCKET},server,nowait \
         -enable-kvm \
-        -m 1337M \
-        -display curses \
+        -m 50M \
         -serial mon:stdio \
-        -append "Hello" \
-        -device virtio-net,netdev=network0 -netdev tap,id=network0,ifname=tap0,script=no,downscript=no \
+        -curses \
         -kernel ${KERNEL}
+        # -cdrom ${KERNEL}.iso
+        # -append "Hello" \
+        # -S
+        # -device virtio-net,netdev=network0 -netdev tap,id=network0,ifname=tap0,script=no,downscript=no \
         # build/kernel.iso
         "$@"
 }
 
 monitor() {
-    if [ "$1" == "" ]; then
-        sudo ${QEMU_MONITOR}
-    else
-        echo "$1" | sudo ${QEMU_MONITOR} >/dev/null
-    fi
+    [ "$1" == "" ] && sudo ${QEMU_MONITOR} || echo "$1" | sudo ${QEMU_MONITOR} >/dev/null
 }
 
 reload() {

src/arch/x86/main.zig

@@ -9,7 +9,7 @@ const printf = @import("../../vga.zig").printf;
 
 /// x86 specific intialization
 /// first entry point (see linker.ld)
-pub fn x86_main(info: *const MultibootInfo) void {
+pub fn x86_main(info: *const multibootInfo) void {
     var allocator = mem.initialize(info);
 
     // gdt.initialize();

src/arch/x86/mem.zig

@@ -2,17 +2,16 @@ usingnamespace @import("kernel").multiboot;
 const assert = @import("std").debug.assert;
 const vga = @import("../../vga.zig");
 const std = @import("std");
-const printf = @import("../../vga.zig").printf;
-
-pub fn initialize(info: *const MultibootInfo) bumpAllocator {
-    assert((info.flags & MULTIBOOT_INFO_MEMORY) != 0);
-    assert((info.flags & MULTIBOOT_INFO_MEM_MAP) != 0);
+const println = @import("../../vga.zig").println;
 
+pub fn initialize(info: *const multibootInfo) void {
+    // assert((info.flags & MULTIBOOT_INFO_MEMORY) != 0);
+    // assert((info.flags & MULTIBOOT_INFO_MEM_MAP) != 0);
     format_multibootinfo(info);
-    return bumpAllocator.new(info);
+    // return bumpAllocator.new(info);
 }
 
-pub fn format_multibootentry(entry: *MultibootMMapEntry) void {
+pub fn format_multibootentry(entry: *multibootMMapEntry) void {
     if (entry.type == MULTIBOOT_MEMORY_AVAILABLE) {
         vga.printf("AVAILABLE: ");
     } else {
@@ -26,132 +25,118 @@ pub fn format_multibootentry(entry: *MultibootMMapEntry) void {
     }
 }
 
-pub fn format_multibootinfo(info: *const MultibootInfo) void {
-    var cmdline_ptr = @intToPtr([*c]const u8, info.cmdline);
-    var cmdline = @ptrCast([*c]const u8, cmdline_ptr);
-    // var cmdline = std.cstr.toSliceConst(info.cmdline);
-    vga.printf("lower: {x}\n", info.mem_lower);
-    vga.printf("upper: {x}\n", info.mem_upper);
-    vga.printf("mmap_l: {}\n", info.mmap_length);
-    vga.printf("mmap_a: {x}\n", info.mmap_addr);
-    vga.printf("cmdline: {x}\n", cmdline_ptr);
-    vga.printf("cmdline: {}\n", cmdline);
-
-    var map: usize = info.mmap_addr;
-    while (map < info.mmap_addr + info.mmap_length) {
-        var entry = @intToPtr(*MultibootMMapEntry, map);
-        format_multibootentry(entry);
-        map += entry.size + @sizeOf(@typeOf(entry.size));
-    }
+pub fn format_multibootinfo(info: *const multibootInfo) void {
+    println("-- multiboot2 info --");
+    // println("start: {}, end {}, size {}", info.start_address(), info.end_address(), info.total_size());
 }
 
 // returns each available physical frame one by one in order
-pub const bumpAllocator = struct {
-    next_free_frame: physFrame,
-    current_area: ?*MultibootMMapEntry,
-    info: *const MultibootInfo,
+// pub const bumpAllocator = struct {
+//     next_free_frame: physFrame,
+//     current_area: ?*multibootMMapEntry,
+//     info: *const multibootInfo,
 
-    pub fn new(info: *const MultibootInfo) bumpAllocator {
-        const first_area = @intToPtr(*MultibootMMapEntry, info.mmap_addr);
-        var allocator = bumpAllocator{
-            .current_area = first_area,
-            .next_free_frame = physFrame.from_addr(first_area.addr),
-            .info = info,
-        };
-        // allocator.choose_next_area();
-        return allocator;
-    }
+//     pub fn new(info: *const multibootInfo) bumpAllocator {
+//         const first_area = @intToPtr(*MultibootMMapEntry, info.mmap_addr);
+//         var allocator = bumpAllocator{
+//             .current_area = first_area,
+//             .next_free_frame = physFrame.from_addr(first_area.addr),
+//             .info = info,
+//         };
+//         // allocator.choose_next_area();
+//         return allocator;
+//     }
 
-    pub fn allocate(self: var, count: u64) ?physFrame {
-        if (count == 0) {
-            return null;
-        }
-        if (self.current_area == null) {
-            return null;
-        }
-        if (self.current_area.?.type != MULTIBOOT_MEMORY_AVAILABLE) {
-            self.choose_next_area();
-            return self.allocate(count);
-        }
+//     pub fn allocate(self: var, count: u64) ?physFrame {
+//         if (count == 0) {
+//             return null;
+//         }
+//         if (self.current_area == null) {
+//             return null;
+//         }
+//         if (self.current_area.?.type != MULTIBOOT_MEMORY_AVAILABLE) {
+//             self.choose_next_area();
+//             return self.allocate(count);
+//         }
 
-        const start_frame = self.next_free_frame;
-        const end_frame = self.next_free_frame.add(count - 1);
-        const current_area_last_frame = physFrame.from_addr(self.current_area.?.addr + self.current_area.?.len);
-        if (end_frame.number > current_area_last_frame.number) {
-            self.choose_next_area();
-            return self.allocate(count);
-        }
-        self.next_free_frame.number += count;
-        return start_frame;
-    }
+//         const start_frame = self.next_free_frame;
+//         const end_frame = self.next_free_frame.add(count - 1);
+//         const current_area_last_frame = physFrame.from_addr(self.current_area.?.addr + self.current_area.?.len);
+//         if (end_frame.number > current_area_last_frame.number) {
+//             self.choose_next_area();
+//             return self.allocate(count);
+//         }
+//         self.next_free_frame.number += count;
+//         return start_frame;
+//     }
 
-    pub fn choose_next_area(self: var) void {
-        printf("choosing next area\n");
-        const current = self.current_area.?;
-        var next_area = @ptrToInt(current) + current.size + @sizeOf(@typeOf(current));
-        if (next_area >= self.info.mmap_addr + self.info.mmap_length) {
-            self.current_area = null;
-        } else {
-            format_multibootentry(self.current_area.?);
-            self.current_area = @intToPtr(*MultibootMMapEntry, next_area);
-            format_multibootentry(self.current_area.?);
-            self.next_free_frame = physFrame.from_addr(self.current_area.?.addr);
-        }
-    }
-};
+//     pub fn choose_next_area(self: var) void {
+//         printf("choosing next area\n");
+//         const current = self.current_area.?;
+//         var next_area = @ptrToInt(current) + current.size + @sizeOf(@typeOf(current));
+//         if (next_area >= self.info.mmap_addr + self.info.mmap_length) {
+//             self.current_area = null;
+//         } else {
+//             format_multibootentry(self.current_area.?);
+//             self.current_area = @intToPtr(*MultibootMMapEntry, next_area);
+//             format_multibootentry(self.current_area.?);
+//             self.next_free_frame = physFrame.from_addr(self.current_area.?.addr);
+//         }
+//     }
+// };
 
-pub const PAGE_SIZE = 4096;
+// pub const PAGE_SIZE = 4096;
 
-pub const physFrame = struct {
-    number: u64,
+// pub const physFrame = struct {
+//     number: u64,
 
-    pub fn from_addr(addr: u64) physFrame {
-        return physFrame{ .number = @divTrunc(addr, PAGE_SIZE) };
-    }
+//     pub fn from_addr(addr: u64) physFrame {
+//         return physFrame{ .number = @divTrunc(addr, PAGE_SIZE) };
+//     }
 
-    pub fn add(self: physFrame, count: u64) physFrame {
-        return physFrame{ .number = self.number + count };
-    }
+//     pub fn add(self: physFrame, count: u64) physFrame {
+//         return physFrame{ .number = self.number + count };
+//     }
 
-    pub fn start_addr(self: physFrame) u64 {
-        return (self.number * PAGE_SIZE);
-    }
-};
+//     pub fn start_addr(self: physFrame) u64 {
+//         return (self.number * PAGE_SIZE);
+//     }
+// };
 
-const PageDirectory = packed struct {
-    entries: [1024]PageDirectoryEntry,
-};
+// const PageDirectory = packed struct {
+//     entries: [1024]PageDirectoryEntry,
+// };
 
-const PageDirectoryEntry = packed struct {
-    address: u21,
-    available: u2,
-    ignored: u1,
-    size: u1,
-    zero: u1,
-    accessed: u1,
-    cache_disabled: u1,
-    write_through: u1,
-    user: u1,
-    writeable: u1,
-    present: u1,
-};
+// const PageDirectoryEntry = packed struct {
+//     address: u21,
+//     available: u2,
+//     ignored: u1,
+//     size: u1,
+//     zero: u1,
+//     accessed: u1,
+//     cache_disabled: u1,
+//     write_through: u1,
+//     user: u1,
+//     writeable: u1,
+//     present: u1,
+// };
 
-const PageTable = packed struct {
-    entries: [1024]PageTableEntry,
-};
+// const PageTable = packed struct {
+//     entries: [1024]PageTableEntry,
+// };
 
-const PageTableEntry = packed struct {
-    address: u21,
-    available: u2,
-    global: u1,
-    zero: u1,
-    dirty: u1,
-    accessed: u1,
-    cache_disabled: u1,
-    write_through: u1,
-    user: u1,
-    writeable: u1,
-    present: u1,
-};
+// const PageTableEntry = packed struct {
+//     address: u21,
+//     available: u2,
+//     global: u1,
+//     zero: u1,
+//     dirty: u1,
+//     accessed: u1,
+//     cache_disabled: u1,
+//     write_through: u1,
+//     user: u1,
+//     writeable: u1,
+//     present: u1,
+// };
 
-// assert(@sizeOf(PageTableEntry) == 32);
+// // assert(@sizeOf(PageTableEntry) == 32);

src/index.zig

@@ -1,3 +1,3 @@
 pub const vga = @import("vga.zig");
 pub const main = @import("main.zig");
-pub const multiboot = @import("multiboot.zig");
+pub const multiboot = @import("multiboot2.zig");

src/main.zig

@@ -1,24 +1,29 @@
-usingnamespace @import("multiboot.zig");
+usingnamespace @import("multiboot2.zig");
 usingnamespace @import("vga.zig");
-const pci = @import("pci.zig");
+
 const arch = @import("arch/x86/lib/index.zig");
-const console = @import("console.zig");
 const x86 = @import("arch/x86/main.zig");
+const multiboot = @import("multiboot2.zig");
+
 const assert = @import("std").debug.assert;
+const pci = @import("pci.zig");
+const console = @import("console.zig");
 
 // arch independant initialization
-export fn kmain(magic: u32, info: *const MultibootInfo) noreturn {
-    assert(magic == MULTIBOOT_BOOTLOADER_MAGIC);
+export fn kmain(magic: u32, info_addr: u32) noreturn {
+    println("--- hello x86_main ---");
+    assert(magic == MULTIBOOT2_BOOTLOADER_MAGIC);
+
+    const info = multiboot.load(info_addr);
     console.initialize();
 
-    printf("--- hello x86_main ---\n");
+    println("--- hello x86_main ---");
 
-    x86.x86_main(info);
+    x86.x86_main(&info);
 
     // pagefault_test(0xfeffc000);
 
-    printf("\n--- arch indepent boot ---\n");
-
+    println("--- end ---");
     while (true) {}
 }
 

src/multiboot.zig

@@ -1,131 +0,0 @@
-// MULTIBOOT1
-// https://www.gnu.org/software/grub/manual/multiboot/multiboot.html
-
-// zig fmt: off
-const tty = @import("tty.zig");
-const cstr = @import("std").cstr;
-const Process = @import("process.zig").Process;
-
-// This should be in EAX.
-pub const MULTIBOOT_BOOTLOADER_MAGIC = 0x2BADB002;
-
-// Is there basic lower/upper memory information?
-pub const MULTIBOOT_INFO_MEMORY      = 0x00000001;
-// Is there a full memory map?
-pub const MULTIBOOT_INFO_MEM_MAP     = 0x00000040;
-// System information structure passed by the bootloader.
-pub const MultibootInfo = packed struct {
-    // Multiboot info version number.
-    flags: u32,
-
-    // Available memory from BIOS.
-    mem_lower: u32,
-    mem_upper: u32,
-
-    // "root" partition.
-    boot_device: u32,
-
-    // Kernel command line.
-    cmdline: u32,
-
-    // Boot-Module list.
-    mods_count: u32,
-    mods_addr:  u32,
-
-    // TODO: use the real types here.
-    u: u128,
-
-    // Memory Mapping buffer.
-    mmap_length: u32,
-    mmap_addr:   u32,
-
-    // Drive Info buffer.
-    drives_length: u32,
-    drives_addr:   u32,
-
-    // ROM configuration table.
-    config_table: u32,
-
-    // Boot Loader Name.
-    boot_loader_name: u32,
-
-    // APM table.
-    apm_table: u32,
-
-    // Video.
-    vbe_control_info:  u32,
-    vbe_mode_info:     u32,
-    vbe_mode:          u16,
-    vbe_interface_seg: u16,
-    vbe_interface_off: u16,
-    vbe_interface_len: u16,
-
-    ////
-    // Return the ending address of the last module.
-    //
-    pub fn lastModuleEnd(self: *const MultibootInfo) usize {
-        const mods = @intToPtr([*]MultibootModule, self.mods_addr);
-        return mods[self.mods_count - 1].mod_end;
-    }
-
-    ////
-    // Load all the modules passed by the bootloader.
-    //
-    // pub fn loadModules(self: *const MultibootInfo) void {
-    //     const mods = @intToPtr([*]MultibootModule, self.mods_addr)[0..self.mods_count];
-
-    //     for (mods) |mod| {
-    //         const cmdline = cstr.toSlice(@intToPtr([*]u8, mod.cmdline));
-    //         tty.step("Loading \"{}\"", cmdline);
-
-    //         _ = Process.create(mod.mod_start, null);
-    //         // TODO: deallocate the original memory.
-
-    //         tty.stepOK();
-    //     }
-    // }
-};
-
-// Types of memory map entries.
-pub const MULTIBOOT_MEMORY_AVAILABLE = 1;
-pub const MULTIBOOT_MEMORY_RESERVED  = 2;
-
-// Entries in the memory map.
-pub const MultibootMMapEntry = packed struct {
-    size: u32,
-    addr: u64,
-    len:  u64,
-    type: u32,
-};
-
-pub const MultibootModule = packed struct {
-    // The memory used goes from bytes 'mod_start' to 'mod_end-1' inclusive.
-    mod_start: u32,
-    mod_end:   u32,
-
-    cmdline:   u32,  // Module command line.
-    pad:       u32,  // Padding to take it to 16 bytes (must be zero).
-};
-
-// Multiboot structure to be read by the bootloader.
-const MultibootHeader = packed struct {
-    magic:    u32,  // Must be equal to header magic number.
-    flags:    u32,  // Feature flags.
-    checksum: u32,  // Above fields plus this one must equal 0 mod 2^32.
-};
-// NOTE: this structure is incomplete.
-
-// Place the header at the very beginning of the binary.
-export const multiboot_header align(4) linksection(".multiboot") = multiboot: {
-    const MAGIC   = u32(0x1BADB002);  // multiboot magic
-    const ALIGN   = u32(1 << 0);      // Align loaded modules.
-    const MEMINFO = u32(1 << 1);      // Receive a memory map from the bootloader.
-    const CMDLINE = u32(1 << 2);      // Receive a cmdline from the bootloader
-    const FLAGS   = ALIGN | MEMINFO | CMDLINE;  // Combine the flags.
-
-    break :multiboot MultibootHeader {
-        .magic    = MAGIC,
-        .flags    = FLAGS,
-        .checksum = ~(MAGIC +% FLAGS) +% 1,
-    };
-};

src/vga.zig

@@ -59,6 +59,9 @@ const Errors = error{};
 pub fn printf(comptime format: []const u8, args: ...) void {
     var a = std.fmt.format({}, Errors, printCallback, format, args);
 }
+pub fn println(comptime format: []const u8, args: ...) void {
+    var a = std.fmt.format({}, Errors, printCallback, format ++ "\n", args);
+}
 
 fn printCallback(context: void, string: []const u8) Errors!void {
     vga.writeString(string);