Do not hardcode fb addr in Vga

kernel/src/drivers/gpu/fb.rs

@@ -173,6 +173,11 @@ impl Framebuffer {
         unsafe { self.buf.base_addr }
     }
 
+    #[inline]
+    pub fn framebuffer_size(&self) -> usize {
+        self.fb_info.screen_size as usize
+    }
+
     #[inline]
     pub fn bus_addr(&self) -> usize {
         self.fb_info.bus_addr as usize

kernel/src/fs/file.rs

@@ -1,8 +1,8 @@
 //! File handle for process
 
+use crate::thread;
 use alloc::{string::String, sync::Arc};
 use core::fmt;
-use crate::thread;
 
 use rcore_fs::vfs::{FsError, INode, Metadata, PollStatus, Result};
 

kernel/src/fs/vga.rs

@@ -31,15 +31,20 @@ impl INode for Vga {
     }
     fn write_at(&self, _offset: usize, _buf: &[u8]) -> Result<usize> {
         info!("the _offset is {} {}", _offset, _buf[0]);
+        let lock = FRAME_BUFFER.lock();
+        if let Some(ref frame_buffer) = *lock {
             use core::slice;
             let frame_buffer_data = unsafe {
                 slice::from_raw_parts_mut(
-                phys_to_virt(0xfd00_0000) as *mut u8,
+                    frame_buffer.base_addr() as *mut u8,
-                (1024 * 768 * 3) as usize,
+                    frame_buffer.framebuffer_size(),
                 )
             };
             frame_buffer_data.copy_from_slice(&_buf);
-        return Ok(1024 * 768 * 3);
+            Ok(frame_buffer.framebuffer_size())
+        } else {
+            Err(FsError::EntryNotFound)
+        }
     }
     fn poll(&self) -> Result<PollStatus> {
         Ok(PollStatus {