loader: pass more things to the kernel

src/arch/amd64/root.zig

@@ -748,4 +748,5 @@ pub const IdtEntry = extern struct {
 
 pub const BootInfo = struct {
     cpu_features: CpuFeatures,
+    hypervisor_info: ?hypervisor.Info,
 };

src/kern/amd64/init.zig

@@ -109,6 +109,7 @@ extern var __percpu_start: u8;
 
 pub fn early_init() linksection(r.init) void {
     amd64.cpu_features = r.boot_info.arch_info.cpu_features;
+    amd64.hypervisor.info = r.boot_info.arch_info.hypervisor_info;
     early_cpu_init();
 
     impl.cpu_offsets = &initial_offsets;

src/loader/amd64/impl.zig

@@ -114,4 +114,5 @@ pub fn debug_write(c: u8) void {
 pub fn init() void {
     amd64.detect_cpu_features();
     r.loader_info.arch_info.cpu_features = amd64.cpu_features;
+    r.loader_info.arch_info.hypervisor_info = amd64.hypervisor.info;
 }

src/loader/limine/impl.zig

@@ -62,6 +62,8 @@ pub fn get_image_layout() r.ImageLayout {
     };
 }
 
+var cmdline: [256]u8 = undefined;
+
 export fn loader_entry() callconv(.c) void {
     var kernel: ?*anyopaque = null;
     var module_start: usize = 0;
@@ -148,7 +150,17 @@ export fn loader_entry() callconv(.c) void {
     }
 
     if (cmdline_request.response) |resp| {
-        r.loader_info.cmdline = std.mem.span(resp.cmdline);
+        if (resp.cmdline) |c| {
+            const span = std.mem.span(c);
+            if (span.len > cmdline.len) {
+                r.loader_info.cmdline = "TOOLONG";
+            } else {
+                std.mem.copyForwards(u8, &cmdline, span);
+                r.loader_info.cmdline = cmdline[0..span.len];
+            }
+        } else {
+            r.loader_info.cmdline = &.{};
+        }
     }
 
     r.main(kernel.?);