feat: add initial impl of efi-stub and kernel

arch/x86/boot/build.zig

@@ -0,0 +1,86 @@
+const std = @import("std");
+const kernel_build = @import("../../../kernel/build.zig");
+const Step = std.Build.Step;
+
+pub fn buildSetup(b: *std.Build, target: std.Build.ResolvedTarget, optimize: std.builtin.OptimizeMode, kcapsule: *Step.Compile) *Step.Compile {
+    const offset_generate = b.addSystemCommand(&[_][]const u8{
+        "sh",
+        "arch/x86/boot/helper.sh",
+        "generate_offset_header",
+    });
+    offset_generate.addFileArg(kcapsule.getEmittedBin());
+    offset_generate.step.dependOn(&kcapsule.step);
+    const setup = b.addExecutable(.{
+        .name = "setup",
+        .use_lld = true,
+        .use_llvm = true,
+        .root_module = b.createModule(.{
+            .root_source_file = b.path("arch/x86/boot/setup/stage1.zig"),
+            .target = target,
+            .optimize = optimize,
+        }),
+    });
+    setup.step.dependOn(&offset_generate.step);
+    setup.step.addWatchInput(b.path("arch/x86/boot/offset.h")) catch {};
+    setup.addAssemblyFile(b.path("arch/x86/boot/header.S"));
+    setup.addIncludePath(b.path("include"));
+    setup.addIncludePath(b.path("arch/x86/boot"));
+    setup.setLinkerScript(b.path("arch/x86/boot/setup.ld"));
+    return setup;
+}
+pub fn buildKcapsule(b: *std.Build, target: std.Build.ResolvedTarget, optimize: std.builtin.OptimizeMode) *Step.Compile {
+    const kernel = kernel_build.buildKernelBin(b, target, optimize);
+    const kcapsule = b.addExecutable(.{
+        .name = "kcapsule",
+        .use_lld = true,
+        .use_llvm = true,
+        .root_module = b.createModule(.{
+            .root_source_file = b.path("arch/x86/boot/extractor.zig"),
+            .target = target,
+            .optimize = optimize,
+            .pic = true,
+        }),
+    });
+    const efi_target = b.resolveTargetQuery(.{
+        .cpu_arch = .x86_64,
+        .os_tag = .freestanding,
+        .abi = .msvc,
+    });
+    const efi_loader = b.addObject(.{
+        .name = "efi_loader",
+        .use_lld = true,
+        .use_llvm = true,
+        .root_module = b.createModule(.{
+            .root_source_file = b.path("drivers/firmware/efi/x86.zig"),
+            .target = efi_target,
+            .optimize = optimize,
+            .pic = true,
+        }),
+    });
+    kcapsule.pie = true;
+    kcapsule.entry = .{ .symbol_name = "efi_pe_entry" };
+    kcapsule.addObject(efi_loader);
+    kcapsule.addAssemblyFile(b.path("arch/x86/boot/payload.S"));
+    kcapsule.setLinkerScript(b.path("arch/x86/boot/kcapsule.ld"));
+    kcapsule.step.dependOn(&kernel.step);
+
+    return kcapsule;
+}
+pub fn buildImage(b: *std.Build, optimize: std.builtin.OptimizeMode) *Step {
+    const target = b.resolveTargetQuery(.{ .cpu_arch = .x86_64, .os_tag = .freestanding, .abi = .none });
+
+    const kcapsule = buildKcapsule(b, target, optimize);
+    const setup = buildSetup(b, target, optimize, kcapsule);
+    const image = b.addSystemCommand(&[_][]const u8{
+        "sh",
+        "arch/x86/boot/helper.sh",
+        "build_image",
+    });
+
+    image.addFileArg(setup.getEmittedBin());
+    image.addFileArg(kcapsule.getEmittedBin());
+    image.step.dependOn(&setup.step);
+    image.step.dependOn(&kcapsule.step);
+
+    return &image.step;
+}