Use FRAMEBUFFER variables for graphical debug

src/arch/x86_64/graphical_debug/mod.rs

+use core::str;
 use spin::Mutex;
 
 use crate::memory::Frame;
@@ -7,31 +8,45 @@ use crate::paging::mapper::PageFlushAll;
 
 pub use self::debug::DebugDisplay;
 use self::display::Display;
-use self::mode_info::VBEModeInfo;
 use self::primitive::fast_set64;
 
 pub mod debug;
 pub mod display;
-pub mod mode_info;
 pub mod primitive;
 
 pub static FONT: &'static [u8] = include_bytes!("../../../../res/unifont.font");
 
 pub static DEBUG_DISPLAY: Mutex<Option<DebugDisplay>> = Mutex::new(None);
 
-pub fn init(active_table: &mut ActivePageTable) {
+pub fn init(active_table: &mut ActivePageTable, env: &[u8]) {
     println!("Starting graphical debug");
 
-    let width;
-    let height;
-    let physbaseptr;
+    let mut width = 0;
+    let mut height = 0;
+    let mut physbaseptr = 0;
 
-    {
-        let mode_info_addr = 0x5200 + crate::PHYS_OFFSET;
-        let mode_info = unsafe { &*(mode_info_addr as *const VBEModeInfo) };
-        width = mode_info.xresolution as usize;
-        height = mode_info.yresolution as usize;
-        physbaseptr = mode_info.physbaseptr as usize;
+    //TODO: should errors be reported?
+    for line in str::from_utf8(env).unwrap_or("").lines() {
+        let mut parts = line.splitn(2, '=');
+        let name = parts.next().unwrap_or("");
+        let value = parts.next().unwrap_or("");
+
+        if name == "FRAMEBUFFER_ADDR" {
+            physbaseptr = usize::from_str_radix(value, 16).unwrap_or(0);
+        }
+
+        if name == "FRAMEBUFFER_WIDTH" {
+            width = usize::from_str_radix(value, 16).unwrap_or(0);
+        }
+
+        if name == "FRAMEBUFFER_HEIGHT" {
+            height = usize::from_str_radix(value, 16).unwrap_or(0);
+        }
+    }
+
+    if physbaseptr == 0 || width == 0 || height == 0 {
+        println!("Framebuffer not found");
+        return;
     }
 
     println!("Framebuffer {}x{} at {:X}", width, height, physbaseptr);

src/arch/x86_64/graphical_debug/mode_info.rs

-/// The info of the VBE mode
-#[derive(Copy, Clone, Default, Debug)]
-#[repr(packed)]
-pub struct VBEModeInfo {
-    attributes: u16,
-    win_a: u8,
-    win_b: u8,
-    granularity: u16,
-    winsize: u16,
-    segment_a: u16,
-    segment_b: u16,
-    winfuncptr: u32,
-    bytesperscanline: u16,
-    pub xresolution: u16,
-    pub yresolution: u16,
-    xcharsize: u8,
-    ycharsize: u8,
-    numberofplanes: u8,
-    bitsperpixel: u8,
-    numberofbanks: u8,
-    memorymodel: u8,
-    banksize: u8,
-    numberofimagepages: u8,
-    unused: u8,
-    redmasksize: u8,
-    redfieldposition: u8,
-    greenmasksize: u8,
-    greenfieldposition: u8,
-    bluemasksize: u8,
-    bluefieldposition: u8,
-    rsvdmasksize: u8,
-    rsvdfieldposition: u8,
-    directcolormodeinfo: u8,
-    pub physbaseptr: u32,
-    offscreenmemoryoffset: u32,
-    offscreenmemsize: u16,
-}

src/arch/x86_64/start.rs

@@ -149,9 +149,12 @@ pub unsafe extern fn kstart(args_ptr: *const KernelArgs) -> ! {
         // Activate memory logging
         log::init();
 
+        // Convert env to slice
+        let env = slice::from_raw_parts((env_base + crate::PHYS_OFFSET) as *const u8, env_size);
+
         // Use graphical debug
         #[cfg(feature="graphical_debug")]
-        graphical_debug::init(&mut active_table);
+        graphical_debug::init(&mut active_table, env);
 
         #[cfg(feature = "system76_ec_debug")]
         device::system76_ec::init();
@@ -175,7 +178,7 @@ pub unsafe extern fn kstart(args_ptr: *const KernelArgs) -> ! {
 
         BSP_READY.store(true, Ordering::SeqCst);
 
-        slice::from_raw_parts((env_base + crate::PHYS_OFFSET) as *const u8, env_size)
+        env
     };
 
     crate::kmain(CPU_COUNT.load(Ordering::SeqCst), env);