Send early kernel prints (before display setup) to serial console

djphoenix · Nov 17, 2016 · e26a099 · e26a099
1 parent ada6df8
commit e26a099
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Showing 4 changed files with 28 additions and 10 deletions.
diff --git a/makefiles/utils.mk b/makefiles/utils.mk
@@ -28,7 +28,7 @@ $(EFIKERN): $(BIN)
 	$(Q) cp $< $@
 
 launch: $(BIN)
-	$(QEMU) -kernel $< -smp cores=2,threads=2 -cpu Broadwell
+	$(QEMU) -kernel $< -smp cores=2,threads=2 -cpu Broadwell -serial stdio
 
 launch-efi: $(EFIKERN) $(EFIBIOS)
-	$(QEMU) -drive file=fat:$(EFIROOT) -smp cores=2,threads=2 -cpu Broadwell -bios $(EFIBIOS)
+	$(QEMU) -drive file=fat:$(EFIROOT) -smp cores=2,threads=2 -cpu Broadwell -bios $(EFIBIOS) -serial stdio
diff --git a/src/boot/x32to64.s b/src/boot/x32to64.s
@@ -220,6 +220,7 @@ x64_entry:
   call reloc_vtables
   call static_init
   call _ZN9Pagetable4initEv
+  call _ZN7Display5setupEv
   mov %rsp, %rbp
   jmp main
 

diff --git a/src/kernlib/display.cpp b/src/kernlib/display.cpp
@@ -37,6 +37,20 @@ class EFIDisplay: public Display {
   void clean();
 };
 
+class SerialDisplay: public Display {
+ public:
+  SerialDisplay() {
+    // TODO: setup serial
+  }
+  void write(const char *str) {
+    char c;
+    while ((c = *str++) != 0) {
+      outportb(0x3F8, c);
+    }
+  }
+  void clean() {}
+};
+
 char *const ConsoleDisplay::base = reinterpret_cast<char*>(0xB8000);
 char *const ConsoleDisplay::top = reinterpret_cast<char*>(0xB8FA0);
 const size_t ConsoleDisplay::size = ConsoleDisplay::top - ConsoleDisplay::base;
@@ -127,20 +141,23 @@ void EFIDisplay::write(const char *str) {
   mutex.release();
 }
 
-static ConsoleDisplay sharedConsole;
-Display *Display::instance = Display::initInstance();
+static SerialDisplay serialConsole;
+Display *Display::instance = &serialConsole;
 Mutex Display::instanceMutex;
 
-Display *Display::initInstance() {
-  if (EFI::getSystemTable()) return new EFIDisplay();
-  return &sharedConsole;
+void Display::setup() {
+  if (instance != &serialConsole) return;
+  if (EFI::getSystemTable()) {
+    instance = new EFIDisplay();
+  } else {
+    instance = new ConsoleDisplay();
+  }
 }
 
 Display *Display::getInstance() {
   if (instance) return instance;
   instanceMutex.lock();
-  if (!instance)
-    instance = initInstance();
+  if (!instance) setup();
   instanceMutex.release();
   return instance;
 }

diff --git a/src/kernlib/include/kernlib/display.hpp b/src/kernlib/include/kernlib/display.hpp
@@ -21,8 +21,8 @@
 class Display {
  private:
   static Mutex instanceMutex;
-  static Display *initInstance();
   static Display *instance;
+  static void setup();
  protected:
   Mutex mutex;
  public: