framebuffer initial clear

crates/boot-interface/src/framebuffer.rs

+#[derive(Debug, Clone, Copy)]
 pub struct FramebufferCreateInfo {
-    pub buf: &'static mut [u8],
+    pub buf: *mut [u8],
     pub width: usize,
     pub height: usize,
     pub pitch: usize,
 }
+
+unsafe impl Sync for FramebufferCreateInfo {}
+unsafe impl Send for FramebufferCreateInfo {}
+
+impl FramebufferCreateInfo {
+    /// # Safety
+    /// this is not synchronized between copies of [`FramebufferCreateInfo`]
+    pub unsafe fn buf_mut(&mut self) -> &'static mut [u8] {
+        unsafe { &mut *self.buf }
+    }
+}

crates/boot-limine/src/framebuffer.rs

-use core::slice;
+use core::ptr;
 
 use hyperion_boot_interface::FramebufferCreateInfo;
 use limine::FramebufferRequest;
+use spin::Once;
 
 //
 
 pub fn framebuffer() -> Option<FramebufferCreateInfo> {
+    static FB_INFO: Once<Option<FramebufferCreateInfo>> = Once::new();
     static FB_REQ: FramebufferRequest = FramebufferRequest::new(0);
 
+    *FB_INFO.call_once(|| {
         FB_REQ
             .get_response()
             .get()
@@ -15,8 +18,7 @@ pub fn framebuffer() -> Option<FramebufferCreateInfo> {
             .flat_map(|resp| resp.framebuffers().iter())
             .filter(|fb| fb.bpp == 32)
             .find_map(|fb| {
-            let buf = unsafe { slice::from_raw_parts_mut(fb.address.as_ptr()?, fb.size()) };
-
+                let buf = ptr::slice_from_raw_parts_mut(fb.address.as_ptr()?, fb.size());
                 Some(FramebufferCreateInfo {
                     buf,
                     width: fb.width as _,
@@ -24,4 +26,13 @@ pub fn framebuffer() -> Option<FramebufferCreateInfo> {
                     pitch: fb.pitch as _,
                 })
             })
+    })
+}
+
+pub fn init_fb() {
+    if let Some(mut fb) = framebuffer() {
+        let buf = unsafe { fb.buf_mut() };
+
+        buf.fill(b'0');
+    }
 }

crates/boot-limine/src/lib.rs

@@ -4,7 +4,7 @@
 
 pub use addr::{hhdm_offset, phys_addr, size, virt_addr};
 pub use cmdline::cmdline;
-pub use framebuffer::framebuffer;
+pub use framebuffer::{framebuffer, init_fb};
 pub use kernel::kernel_file;
 pub use mem::memmap;
 pub use rsdp::rsdp;

crates/framebuffer/src/framebuffer.rs

@@ -45,14 +45,14 @@ impl Framebuffer {
         static FBO: Once<Option<Mutex<Framebuffer>>> = Once::new();
 
         FBO.call_once(|| {
-            let FramebufferCreateInfo {
-                buf,
+            let mut fb @ FramebufferCreateInfo {
                 width,
                 height,
                 pitch,
+                ..
             } = hyperion_boot::framebuffer()?;
             let mut fbo = Framebuffer::new(
-                buf,
+                unsafe { fb.buf_mut() },
                 FramebufferInfo {
                     width,
                     height,

crates/kernel/src/main.rs

@@ -43,6 +43,8 @@ static ALLOCATOR: KernelSlabAlloc<spin::Mutex<()>> = KernelSlabAlloc::new();
 
 #[no_mangle]
 extern "C" fn _start() -> ! {
+    hyperion_boot::init_fb();
+
     if sync::once!() {
         // enable logging and and outputs based on the kernel args,
         // any logging before won't be shown