Implement Linux kernel boot protocol, accept bzimage/initrd as boot configuration

2018-10-05 16:57:57 -03:00 · 2018-10-05 16:57:57 -03:00 · e1c6116a0f
parent 04d282c298
commit e1c6116a0f
6 changed files with 267 additions and 4 deletions
--- a/2
+++ b/2
@ -95,7 +95,7 @@ CORE_FILES=const.js config.js io.js main.js lib.js coverage.js ide.js pci.js flo
 	   memory.js dma.js pit.js vga.js ps2.js pic.js rtc.js uart.js hpet.js acpi.js apic.js ioapic.js \
 	   state.js ne2k.js virtio.js bus.js log.js \
 	   cpu.js debug.js \
-	   elf.js
+	   elf.js kernel.js
 LIB_FILES=9p.js filesystem.js jor1k.js marshall.js utf8.js
 BROWSER_FILES=screen.js \
 		  keyboard.js mouse.js serial.js \
--- a/loader.js
+++ b/loader.js
@ -8,7 +8,7 @@
        "const.js config.js log.js lib.js coverage.js cpu.js debug.js " +
        "io.js main.js ide.js pci.js floppy.js " +
        "memory.js dma.js pit.js vga.js ps2.js pic.js rtc.js uart.js acpi.js apic.js ioapic.js hpet.js " +
-        "ne2k.js state.js virtio.js bus.js elf.js";
+        "ne2k.js state.js virtio.js bus.js elf.js kernel.js";

    var BROWSER_FILES = "main.js screen.js keyboard.js mouse.js serial.js lib.js network.js starter.js worker_bus.js print_stats.js filestorage.js";
    var LIB_FILES = "";
--- a/src/browser/main.js
+++ b/src/browser/main.js
@ -545,6 +545,9 @@
            settings.cdrom = infos.cdrom;
            settings.hda = infos.hda;
            settings.multiboot = infos.multiboot;
+            settings.bzimage = infos.bzimage;
+            settings.initrd = infos.initrd;
+            settings.cmdline = infos.cmdline;

            settings.memory_size = infos.memory_size;
            settings.vga_memory_size = infos.vga_memory_size;
@ -767,6 +770,9 @@
            "cdrom": settings.cdrom,

            "multiboot": settings.multiboot,
+            "bzimage": settings.bzimage,
+            "initrd": settings.initrd,
+            "cmdline": settings.cmdline,

            "initial_state": settings.initial_state,
            "filesystem": settings.filesystem || {},
--- a/src/browser/starter.js
+++ b/src/browser/starter.js
@ -245,6 +245,7 @@ V86Starter.prototype.continue_init = function(emulator, options)
    settings.boot_order = options["boot_order"] || 0x213;
    settings.fda = undefined;
    settings.fdb = undefined;
+    settings.cmdline = options["cmdline"];

    if(options["network_relay_url"])
    {
@ -299,6 +300,12 @@ V86Starter.prototype.continue_init = function(emulator, options)
            case "multiboot":
                settings.multiboot = this.disk_images["multiboot"] = buffer.buffer;
                break;
+            case "bzimage":
+                settings.bzimage = this.disk_images["bzimage"] = buffer.buffer;
+                break;
+            case "initrd":
+                settings.initrd = this.disk_images["initrd"] = buffer.buffer;
+                break;

            case "bios":
                settings.bios = buffer.buffer;
@ -345,7 +352,8 @@ V86Starter.prototype.continue_init = function(emulator, options)
        };

        if(name === "bios" || name === "vga_bios" ||
-            name === "initial_state" || name === "multiboot")
+            name === "initial_state" || name === "multiboot" ||
+            name === "bzimage" || name === "initrd")
        {
            // Ignore async for these because they must be availabe before boot.
            // This should make result.buffer available after the object is loaded
@ -425,6 +433,7 @@ V86Starter.prototype.continue_init = function(emulator, options)
        "bios", "vga_bios",
        "cdrom", "hda", "hdb", "fda", "fdb",
        "initial_state", "multiboot",
+        "bzimage", "initrd",
    ];

    for(var i = 0; i < image_names.length; i++)
--- a/src/cpu.js
+++ b/src/cpu.js
@ -533,7 +533,7 @@ CPU.prototype.set_state = function(state)
    this.devices.pic = state[60];

    this.a20_enabled[0] = state[61];
-    this.fw_value[0] = state;
+    this.fw_value = state[62];

    this.devices.ioapic = state[63];

@ -736,6 +736,17 @@ CPU.prototype.init = function(settings, device_bus)

    this.load_bios();

+    if(settings.bzimage)
+    {
+        dbg_assert(settings.cmdline);
+        const { option_rom } = load_kernel(this.mem8, settings.bzimage, settings.initrd, settings.cmdline);
+
+        if(option_rom)
+        {
+            this.option_roms.push(option_rom);
+        }
+    }
+
    var a20_byte = 0;

    io.register_read(0xB3, this, function()
@ -770,6 +781,9 @@ CPU.prototype.init = function(settings, device_bus)
    });
    io.register_write(0x510, this, undefined, function(value)
    {
+        // https://wiki.osdev.org/QEMU_fw_cfg
+        // https://github.com/qemu/qemu/blob/master/docs/specs/fw_cfg.txt
+
        dbg_log("bios config port, index=" + h(value));

        function i32(x)
--- a/src/kernel.js
+++ b/src/kernel.js
@ -0,0 +1,234 @@
+"use strict";
+
+// https://www.kernel.org/doc/Documentation/x86/boot.txt
+
+const LINUX_BOOT_HDR_SETUP_SECTS = 0x1F1;
+const LINUX_BOOT_HDR_SYSSIZE = 0x1F4;
+const LINUX_BOOT_HDR_VIDMODE = 0x1FA;
+const LINUX_BOOT_HDR_BOOT_FLAG = 0x1FE;
+const LINUX_BOOT_HDR_HEADER = 0x202;
+const LINUX_BOOT_HDR_VERSION = 0x206;
+const LINUX_BOOT_HDR_TYPE_OF_LOADER = 0x210;
+const LINUX_BOOT_HDR_LOADFLAGS = 0x211;
+const LINUX_BOOT_HDR_CODE32_START = 0x214;
+const LINUX_BOOT_HDR_RAMDISK_IMAGE = 0x218;
+const LINUX_BOOT_HDR_RAMDISK_SIZE = 0x21C;
+const LINUX_BOOT_HDR_HEAP_END_PTR = 0x224;
+const LINUX_BOOT_HDR_CMD_LINE_PTR = 0x228;
+const LINUX_BOOT_HDR_INITRD_ADDR_MAX = 0x22C;
+const LINUX_BOOT_HDR_KERNEL_ALIGNMENT = 0x230;
+const LINUX_BOOT_HDR_RELOCATABLE_KERNEL = 0x234;
+const LINUX_BOOT_HDR_MIN_ALIGNMENT = 0x235;
+const LINUX_BOOT_HDR_XLOADFLAGS = 0x236;
+const LINUX_BOOT_HDR_CMDLINE_SIZE = 0x238;
+const LINUX_BOOT_HDR_PAYLOAD_OFFSET = 0x248;
+const LINUX_BOOT_HDR_PAYLOAD_LENGTH = 0x24C;
+const LINUX_BOOT_HDR_PREF_ADDRESS = 0x258;
+const LINUX_BOOT_HDR_INIT_SIZE = 0x260;
+
+const LINUX_BOOT_HDR_CHECKSUM1 = 0xAA55;
+const LINUX_BOOT_HDR_CHECKSUM2 = 0x53726448;
+
+const LINUX_BOOT_HDR_TYPE_OF_LOADER_NOT_ASSIGNED = 0xFF;
+
+const LINUX_BOOT_HDR_LOADFLAGS_LOADED_HIGH = 1 << 0;
+const LINUX_BOOT_HDR_LOADFLAGS_QUIET_FLAG = 1 << 5;
+const LINUX_BOOT_HDR_LOADFLAGS_KEEP_SEGMENTS = 1 << 6;
+const LINUX_BOOT_HDR_LOADFLAGS_CAN_USE_HEAPS = 1 << 7;
+
+
+function load_kernel(mem8, bzimage, initrd, cmdline)
+{
+    dbg_log("Trying to load kernel of size " + bzimage.length);
+
+    const KERNEL_HIGH_ADDRESS = 0x100000;
+
+    // Puts the initrd at the 32 mb boundary. This means the mininum memory size
+    // is 32 mb plus the size of the initrd
+    const INITRD_ADDRESS = 32 << 20;
+
+    const quiet = false;
+
+    const bzimage8 = new Uint8Array(bzimage);
+    const bzimage16 = new Uint16Array(bzimage);
+    const bzimage32 = new Uint32Array(bzimage);
+
+    const setup_sects = bzimage8[LINUX_BOOT_HDR_SETUP_SECTS] || 4;
+    const syssize = bzimage32[LINUX_BOOT_HDR_SYSSIZE >> 2] << 4;
+
+    const vidmode = bzimage16[LINUX_BOOT_HDR_VIDMODE >> 1];
+
+    const checksum1 = bzimage16[LINUX_BOOT_HDR_BOOT_FLAG >> 1];
+    if(checksum1 !== LINUX_BOOT_HDR_CHECKSUM1)
+    {
+        dbg_log("Bad checksum1: " + h(checksum1));
+        return;
+    }
+
+    // Not aligned, so split into two 16-bit reads
+    const checksum2 =
+        bzimage16[LINUX_BOOT_HDR_HEADER >> 1] |
+        bzimage16[LINUX_BOOT_HDR_HEADER + 2 >> 1] << 16;
+    if(checksum2 !== LINUX_BOOT_HDR_CHECKSUM2)
+    {
+        dbg_log("Bad checksum2: " + h(checksum2));
+        return;
+    }
+
+    const protocol = bzimage16[LINUX_BOOT_HDR_VERSION >> 1];
+    dbg_assert(protocol >= 0x202); // older not supported by us
+
+    const flags = bzimage8[LINUX_BOOT_HDR_LOADFLAGS];
+    dbg_assert(flags & LINUX_BOOT_HDR_LOADFLAGS_LOADED_HIGH); // low kernels not supported by us
+
+    // we don't relocate the kernel, so we don't care much about most of these
+
+    const flags2 = bzimage16[LINUX_BOOT_HDR_XLOADFLAGS >> 1];
+    const initrd_addr_max = bzimage32[LINUX_BOOT_HDR_INITRD_ADDR_MAX >> 2];
+    const kernel_alignment = bzimage32[LINUX_BOOT_HDR_KERNEL_ALIGNMENT >> 2];
+    const relocatable_kernel = bzimage8[LINUX_BOOT_HDR_RELOCATABLE_KERNEL];
+    const min_alignment = bzimage8[LINUX_BOOT_HDR_MIN_ALIGNMENT];
+    const cmdline_size = bzimage32[LINUX_BOOT_HDR_CMDLINE_SIZE >> 2];
+    const payload_offset = bzimage32[LINUX_BOOT_HDR_PAYLOAD_OFFSET >> 2];
+    const payload_length = bzimage32[LINUX_BOOT_HDR_PAYLOAD_LENGTH >> 2];
+    const pref_address = bzimage32[LINUX_BOOT_HDR_PREF_ADDRESS >> 2];
+    const pref_address_high = bzimage32[LINUX_BOOT_HDR_PREF_ADDRESS + 4 >> 2];
+    const init_size = bzimage32[LINUX_BOOT_HDR_INIT_SIZE >> 2];
+
+    dbg_log("kernel boot protocol version: " + h(protocol));
+    dbg_log("flags=" + h(flags) + " xflags=" + h(flags2));
+    dbg_log("code32_start=" + h(bzimage32[LINUX_BOOT_HDR_CODE32_START >> 2]));
+    dbg_log("initrd_addr_max=" + h(initrd_addr_max));
+    dbg_log("kernel_alignment=" + h(kernel_alignment));
+    dbg_log("relocatable=" + relocatable_kernel);
+    dbg_log("min_alignment=" + h(min_alignment));
+    dbg_log("cmdline max=" + h(cmdline_size));
+    dbg_log("payload offset=" + h(payload_offset) + " size=" + h(payload_length));
+    dbg_log("pref_address=" + h(pref_address_high) + ":" + h(pref_address));
+    dbg_log("init_size=" + h(init_size));
+
+    const real_mode_segment = 0x8000;
+    const base_ptr = real_mode_segment << 4;
+
+    const heap_end = 0xE000;
+    const heap_end_ptr = heap_end - 0x200;
+
+    // fill in the kernel boot header with infos the kernel needs to know
+
+    bzimage8[LINUX_BOOT_HDR_TYPE_OF_LOADER] = LINUX_BOOT_HDR_TYPE_OF_LOADER_NOT_ASSIGNED;
+
+    const new_flags =
+        (quiet ? flags | LINUX_BOOT_HDR_LOADFLAGS_QUIET_FLAG : flags & ~LINUX_BOOT_HDR_LOADFLAGS_QUIET_FLAG)
+        & ~LINUX_BOOT_HDR_LOADFLAGS_KEEP_SEGMENTS
+        | LINUX_BOOT_HDR_LOADFLAGS_CAN_USE_HEAPS;
+    bzimage8[LINUX_BOOT_HDR_LOADFLAGS] = new_flags;
+
+    bzimage16[LINUX_BOOT_HDR_HEAP_END_PTR >> 1] = heap_end_ptr;
+
+    // should parse the vga=... paramter from cmdline here, but we don't really care
+    bzimage16[LINUX_BOOT_HDR_VIDMODE >> 1] = 0xFFFF; // normal
+
+    dbg_log("heap_end_ptr=" + h(heap_end_ptr));
+
+    cmdline += "\x00";
+    dbg_assert(cmdline.length < cmdline_size);
+
+    const cmd_line_ptr = base_ptr + heap_end;
+    dbg_log("cmd_line_ptr=" + h(cmd_line_ptr));
+
+    bzimage32[LINUX_BOOT_HDR_CMD_LINE_PTR >> 2] = cmd_line_ptr;
+    for(let i = 0; i < cmdline.length; i++)
+    {
+        mem8[cmd_line_ptr + i] = cmdline.charCodeAt(i);
+    }
+
+    const prot_mode_kernel_start = (setup_sects + 1) * 512;
+    dbg_log("prot_mode_kernel_start=" + h(prot_mode_kernel_start));
+
+    const real_mode_kernel = new Uint8Array(bzimage, 0, prot_mode_kernel_start);
+    const protected_mode_kernel = new Uint8Array(bzimage, prot_mode_kernel_start);
+
+    let ramdisk_address = 0;
+    let ramdisk_size = 0;
+
+    if(initrd)
+    {
+        ramdisk_address = INITRD_ADDRESS;
+        ramdisk_size = initrd.byteLength;
+
+        dbg_assert(KERNEL_HIGH_ADDRESS + protected_mode_kernel.length < ramdisk_address);
+
+        mem8.set(new Uint8Array(initrd), ramdisk_address);
+    }
+
+    bzimage32[LINUX_BOOT_HDR_RAMDISK_IMAGE >> 2] = ramdisk_address;
+    bzimage32[LINUX_BOOT_HDR_RAMDISK_SIZE >> 2] = ramdisk_size;
+
+    dbg_assert(base_ptr + real_mode_kernel.length < 0xA0000);
+
+    mem8.set(real_mode_kernel, base_ptr);
+    mem8.set(protected_mode_kernel, KERNEL_HIGH_ADDRESS);
+
+    return {
+        option_rom:
+        {
+            name: "genroms/kernel.bin",
+            data: make_linux_boot_rom(real_mode_segment, heap_end),
+        }
+    };
+}
+
+function make_linux_boot_rom(real_mode_segment, heap_end)
+{
+    // This rom will be executed by seabios after its initialisation
+    // It sets up segment registers, the stack and calls the kernel real mode entry point
+
+    const SIZE = 0x200;
+
+    const data8 = new Uint8Array(0x100);
+    const data16 = new Uint16Array(data8.buffer);
+
+    data16[0] = 0xAA55;
+    data8[2] = SIZE / 0x200;
+
+    let i = 3;
+
+    data8[i++] = 0xFA; // cli
+    data8[i++] = 0xB8; // mov ax, real_mode_segment
+    data8[i++] = real_mode_segment >> 0;
+    data8[i++] = real_mode_segment >> 8;
+    data8[i++] = 0x8E; // mov es, ax
+    data8[i++] = 0xC0;
+    data8[i++] = 0x8E; // mov ds, ax
+    data8[i++] = 0xD8;
+    data8[i++] = 0x8E; // mov fs, ax
+    data8[i++] = 0xE0;
+    data8[i++] = 0x8E; // mov gs, ax
+    data8[i++] = 0xE8;
+    data8[i++] = 0x8E; // mov ss, ax
+    data8[i++] = 0xD0;
+    data8[i++] = 0xBC; // mov sp, heap_end
+    data8[i++] = heap_end >> 0;
+    data8[i++] = heap_end >> 8;
+    data8[i++] = 0xEA; // jmp (real_mode_segment+0x20):0x0
+    data8[i++] = 0x00;
+    data8[i++] = 0x00;
+    data8[i++] = real_mode_segment + 0x20 >> 0;
+    data8[i++] = real_mode_segment + 0x20 >> 8;
+
+    dbg_assert(i < SIZE);
+
+    const checksum_index = i;
+    data8[checksum_index] = 0;
+
+    let checksum = 0;
+
+    for(let i = 0; i < data8.length; i++)
+    {
+        checksum += data8[i];
+    }
+
+    data8[checksum_index] = -checksum;
+
+    return data8;
+}