Add emergency_console

gifnksm · May 18, 2021 · 159f253 · 159f253
1 parent 457490e
commit 159f253
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Showing 6 changed files with 95 additions and 30 deletions.
diff --git a/src/emergency_console.rs b/src/emergency_console.rs
@@ -0,0 +1,47 @@
+use crate::{
+    font,
+    framebuffer::{self, Drawer, ScreenInfo},
+    graphics::{Color, Draw, Point, Rectangle},
+};
+use core::fmt;
+
+pub(crate) fn with_console(f: impl FnOnce(&mut EmergencyConsole<'_>)) -> ! {
+    let screen_info = *framebuffer::info();
+    let mut drawer = unsafe { framebuffer::emergency_lock_drawer() };
+    let mut console = EmergencyConsole {
+        screen_info,
+        pos: Point::new(0, 0),
+        drawer: &mut *drawer,
+    };
+
+    f(&mut console);
+
+    crate::hlt_loop();
+}
+
+pub(crate) struct EmergencyConsole<'a> {
+    screen_info: ScreenInfo,
+    pos: Point<i32>,
+    drawer: &'a mut Drawer,
+}
+
+impl fmt::Write for EmergencyConsole<'_> {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        for ch in s.chars() {
+            if ch != '\n' {
+                self.drawer.fill_rect(
+                    Rectangle::new(self.pos, font::FONT_PIXEL_SIZE),
+                    Color::WHITE,
+                );
+                font::draw_char(self.drawer, self.pos, ch, Color::RED);
+                self.pos.x += font::FONT_PIXEL_SIZE.x;
+            }
+
+            if ch == '\n' || self.pos.x + font::FONT_PIXEL_SIZE.x > self.screen_info.width {
+                self.pos.y += font::FONT_PIXEL_SIZE.y;
+                self.pos.x = 0;
+            }
+        }
+        Ok(())
+    }
+}
diff --git a/src/font.rs b/src/font.rs
@@ -47,13 +47,13 @@ pub(crate) fn char_to_byte(ch: char) -> u8 {
     u8::try_from(codepoint).unwrap_or(b'?')
 }
 
-// pub(crate) fn draw_char<D>(drawer: &mut D, pos: Point<i32>, ch: char, color: Color)
-// where
-//     D: Draw,
-// {
-//     let byte = char_to_byte(ch);
-//     draw_byte(drawer, pos, byte, color)
-// }
+pub(crate) fn draw_char<D>(drawer: &mut D, pos: Point<i32>, ch: char, color: Color)
+where
+    D: Draw,
+{
+    let byte = char_to_byte(ch);
+    draw_byte(drawer, pos, byte, color)
+}
 
 // pub(crate) fn draw_str<D>(drawer: &mut D, pos: Point<i32>, s: &str, color: Color)
 // where

diff --git a/src/framebuffer.rs b/src/framebuffer.rs
@@ -42,6 +42,15 @@ pub(crate) fn lock_drawer() -> MutexGuard<'static, Drawer> {
     DRAWER.get().lock()
 }
 
+pub(crate) unsafe fn emergency_lock_drawer() -> MutexGuard<'static, Drawer> {
+    let drawer = DRAWER.get();
+    if let Ok(drawer) = drawer.try_lock() {
+        return drawer;
+    }
+    unsafe { drawer.force_unlock() };
+    drawer.lock()
+}
+
 #[derive(Debug, Clone, Copy)]
 pub(crate) struct ScreenInfo {
     pub(crate) width: i32,

diff --git a/src/interrupt.rs b/src/interrupt.rs
@@ -1,4 +1,5 @@
-use crate::{println, sync::once_cell::OnceCell, xhc};
+use crate::{emergency_console, println, sync::once_cell::OnceCell, xhc};
+use core::fmt::Write as _;
 use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame, PageFaultErrorCode};
 
 #[derive(Debug, Clone, Copy)]
@@ -50,42 +51,43 @@ extern "x86-interrupt" fn page_fault_handler(
 ) {
     use x86_64::registers::control::Cr2;
 
-    println!("EXCEPTION: PAGE FAULT");
-    println!("Accessed Address: {:?}", Cr2::read());
-    println!("Error Code: {:x}", error_code);
-    println!("{:#?}", stack_frame);
-
-    crate::hlt_loop();
+    emergency_console::with_console(|console| {
+        let _ = writeln!(console, "EXCEPTION: PAGE FAULT");
+        let _ = writeln!(console, "Accessed Address: {:?}", Cr2::read());
+        let _ = writeln!(console, "Error Code: {:x}", error_code);
+        let _ = writeln!(console, "{:#?}", stack_frame);
+    });
 }
 
 extern "x86-interrupt" fn general_protection_fault_handler(
     stack_frame: InterruptStackFrame,
     error_code: u64,
 ) {
-    println!("EXCEPTION: GENERAL PROTECTION FAULT");
-    println!("Error Code: {:x}", error_code);
-    println!("{:#?}", stack_frame);
-
-    crate::hlt_loop();
+    emergency_console::with_console(|console| {
+        let _ = writeln!(console, "EXCEPTION: GENERAL PROTECTION FAULT");
+        let _ = writeln!(console, "Error Code: {:x}", error_code);
+        let _ = writeln!(console, "{:#?}", stack_frame);
+    });
 }
 
 extern "x86-interrupt" fn segment_not_present_handler(
     stack_frame: InterruptStackFrame,
     error_code: u64,
 ) {
-    println!("EXCEPTION: STACK NOT PRESENT");
-    println!("Error Code: {:x}", error_code);
-    println!("{:#?}", stack_frame);
-
-    crate::hlt_loop();
+    emergency_console::with_console(|console| {
+        let _ = writeln!(console, "EXCEPTION: STACK NOT PRESENT");
+        let _ = writeln!(console, "Error Code: {:x}", error_code);
+        let _ = writeln!(console, "{:#?}", stack_frame);
+    });
 }
 
 extern "x86-interrupt" fn double_fault_handler(
     stack_frame: InterruptStackFrame,
     error_code: u64,
 ) -> ! {
-    panic!(
-        "EXCEPTION: DOUBLE FAULT\nError Code: {:x}\n{:#?}",
-        error_code, stack_frame
-    );
+    emergency_console::with_console(|console| {
+        let _ = writeln!(console, "EXCEPTION: DOUBLE FAULT",);
+        let _ = writeln!(console, "Error Code: {:x}", error_code);
+        let _ = writeln!(console, "{:#?}", stack_frame);
+    });
 }
diff --git a/src/main.rs b/src/main.rs
@@ -25,6 +25,7 @@ mod co_task;
 mod console;
 mod cxx_support;
 mod desktop;
+mod emergency_console;
 mod error;
 mod font;
 mod framebuffer;
@@ -117,6 +118,8 @@ fn hlt_loop() -> ! {
 #[cfg(not(test))]
 #[panic_handler]
 fn panic(info: &core::panic::PanicInfo) -> ! {
-    error!("{}", info);
-    hlt_loop();
+    use core::fmt::Write as _;
+    emergency_console::with_console(|console| {
+        let _ = write!(console, "{}", info);
+    });
 }
diff --git a/src/sync/mutex.rs b/src/sync/mutex.rs
@@ -26,4 +26,8 @@ where
     pub(crate) fn try_lock(&self) -> Result<MutexGuard<'_, T>> {
         Ok(self.0.try_lock().ok_or(ErrorKind::Deadlock)?)
     }
+
+    pub(crate) unsafe fn force_unlock(&self) {
+        unsafe { self.0.force_unlock() }
+    }
 }