kernel/debug: Initialize the frame buffer console much earlier, if possible.

Previously it was not initialized until "post-VM", but there are
a number of ways VM initialization can go wrong that it would
be nice to know about without needing a serial port.

On arches which map the whole physical memory into the kernel
address space (x86_64, at least), we can get the bluescreen facility
initialized using KERNEL_PMAP_BASE. On other architectures, we
just fail to init then, and do the usual setup later on.

A slight bit of extra code cleanup in blue_screen_init_early:
we now just call module->info.std_ops() rather than a
frame-buffer-console specific method.

headers/private/kernel/frame_buffer_console.h

@@ -34,6 +34,7 @@ bool		frame_buffer_console_available(void);
 status_t	frame_buffer_update(addr_t baseAddress, int32 width, int32 height,
 				int32 depth, int32 bytesPerRow);
 status_t	frame_buffer_console_init(struct kernel_args* args);
+status_t	frame_buffer_console_init_post_vm(struct kernel_args* args);
 status_t	frame_buffer_console_init_post_modules(struct kernel_args* args);
 
 status_t	_user_frame_buffer_update(addr_t baseAddress, int32 width,

src/system/kernel/debug/blue_screen.cpp

@@ -10,7 +10,6 @@
 #include "blue_screen.h"
 
 #include <KernelExport.h>
-#include <frame_buffer_console.h>
 #include <console.h>
 #include <debug.h>
 #include <arch/debug_console.h>
@@ -63,7 +62,7 @@ struct screen_info {
 	int32	args[MAX_ARGS];
 } sScreen;
 
-console_module_info *sModule;
+console_module_info *sModule = NULL;
 
 
 static inline void
@@ -594,16 +593,31 @@ set_paging(int argc, char **argv)
 
 
 status_t
-blue_screen_init(void)
+blue_screen_init_early()
 {
-	extern console_module_info gFrameBufferConsoleModule;
-
 	// we can't use get_module() here, since it's too early in the boot process
-
+	extern console_module_info gFrameBufferConsoleModule;
-	if (!frame_buffer_console_available())
-		return B_ERROR;
-
 	sModule = &gFrameBufferConsoleModule;
+
+	if (sModule->info.std_ops(B_MODULE_INIT) != B_OK) {
+		sModule = NULL;
+		return B_ERROR;
+	}
+
+	sScreen.paging = sScreen.paging_timeout = false;
+	return B_OK;
+}
+
+
+status_t
+blue_screen_init()
+{
+	if (sModule == NULL) {
+		// Early initialization must have previously failed, or never run.
+		if (blue_screen_init_early() != B_OK)
+			return B_ERROR;
+	}
+
 	sScreen.paging = !get_safemode_boolean(
 		"disable_onscreen_paging", false);
 	sScreen.paging_timeout = false;

src/system/kernel/debug/blue_screen.h

@@ -13,7 +13,8 @@
 extern "C" {
 #endif
 
-status_t blue_screen_init(void);
+status_t blue_screen_init_early();
+status_t blue_screen_init();
 status_t blue_screen_enter(bool debugOutput);
 
 bool blue_screen_paging_enabled(void);

src/system/kernel/debug/debug.cpp

@@ -1689,6 +1689,9 @@ debug_init(kernel_args* args)
 
 	debug_paranoia_init();
 	arch_debug_console_init(args);
+
+	if (frame_buffer_console_init(args) == B_OK && blue_screen_init_early() == B_OK)
+		sBlueScreenOutput = true;
 }
 
 
@@ -1715,7 +1718,7 @@ debug_init_post_vm(kernel_args* args)
 
 	debug_heap_init();
 	debug_variables_init();
-	frame_buffer_console_init(args);
+	frame_buffer_console_init_post_vm(args);
 	tracing_init();
 }
 
@@ -1735,7 +1738,7 @@ debug_init_post_settings(struct kernel_args* args)
 	sDebugScreenEnabled = get_safemode_boolean("debug_screen", false);
 
 	if ((sBlueScreenOutput || sDebugScreenEnabled)
-		&& blue_screen_init() != B_OK)
+			&& blue_screen_init() != B_OK)
 		sBlueScreenOutput = sDebugScreenEnabled = false;
 
 	if (sDebugScreenEnabled)

src/system/kernel/debug/frame_buffer_console.cpp

@@ -455,8 +455,27 @@ frame_buffer_console_init(kernel_args* args)
 	if (!args->frame_buffer.enabled)
 		return B_OK;
 
+#if KERNEL_PMAP_BASE
+	const addr_t frameBuffer = (KERNEL_PMAP_BASE
+		+ args->frame_buffer.physical_buffer.start);
+	frame_buffer_update((addr_t)frameBuffer, args->frame_buffer.width,
+		args->frame_buffer.height, args->frame_buffer.depth,
+		args->frame_buffer.bytes_per_row);
+	return B_OK;
+#else
+	return B_NO_INIT;
+#endif
+}
+
+
+status_t
+frame_buffer_console_init_post_vm(kernel_args* args)
+{
+	if (!args->frame_buffer.enabled)
+		return B_OK;
+
 	void* frameBuffer;
-	sConsole.area = map_physical_memory("vesa frame buffer",
+	sConsole.area = map_physical_memory("frame buffer",
 		args->frame_buffer.physical_buffer.start,
 		args->frame_buffer.physical_buffer.size, B_ANY_KERNEL_ADDRESS,
 		B_KERNEL_READ_AREA | B_KERNEL_WRITE_AREA | B_CLONEABLE_AREA,