Fix UEFI console bugs (#16)

include/efi.h

@@ -81,4 +81,7 @@ extern void efi_free (void *ptr);
 extern void efi_free_pages (void *ptr, UINTN pages);
 extern void *efi_allocate_pages (UINTN pages, EFI_MEMORY_TYPE type);
 
+extern int efi_set_text_mode (int on);
+extern void efi_cls (void);
+
 #endif /* _EFI_H */

kern/build.mk

@@ -7,6 +7,7 @@ OBJECTS += kern/efiblock.o
 OBJECTS += kern/efiboot.o
 OBJECTS += kern/efifile.o
 OBJECTS += kern/efimain.o
+OBJECTS += kern/efiterm.o
 OBJECTS += kern/payload.o
 
 OBJECTS += kern/callback.o

kern/efiboot.c

@@ -161,6 +161,9 @@ void efi_boot (EFI_DEVICE_PATH_PROTOCOL *path,
         efi_open_protocol_wrapper;
 #endif
 
+    if (! nt_cmdline->textmode)
+        efi_set_text_mode (0);
+
     /* Start image */
     if ((efirc = bs->StartImage (handle, NULL, NULL)) != 0)
     {

kern/efimain.c

@@ -96,6 +96,8 @@ EFI_STATUS EFIAPI efi_main (EFI_HANDLE image_handle,
     /* Initialise stack cookie */
     init_cookie();
 
+    efi_set_text_mode (1);
+
     /* Print welcome banner */
     printf ("\n\nntloader " VERSION "\n\n");
 

kern/efiterm.c

@@ -0,0 +1,103 @@
+/*
+ *  ntloader  --  Microsoft Windows NT6+ loader
+ *  Copyright (C) 2025  A1ive.
+ *
+ *  ntloader is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published
+ *  by the Free Software Foundation, either version 3 of the License,
+ *  or (at your option) any later version.
+ *
+ *  ntloader is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with ntloader.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <string.h>
+#include <strings.h>
+#include <wchar.h>
+#include "vdisk.h"
+#include "cpio.h"
+#include "ntloader.h"
+#include "bcd.h"
+#include "cmdline.h"
+#include "efi.h"
+
+/* The console control protocol is not a part of the EFI spec,
+ * but defined in Intel's Sample Implementation. */
+
+static EFI_GUID efi_console_ctrl_guid =
+{
+    0xf42f7782, 0x12e, 0x4c12,
+    { 0x99, 0x56, 0x49, 0xf9, 0x43, 0x4, 0xf7, 0x21 },
+};
+
+typedef enum
+{
+    EFI_SCREEN_TEXT,
+    EFI_SCREEN_GRAPHICS,
+    EFI_SCREEN_TEXT_MAX_VALUE
+} EFI_SCREEN_MODE;
+
+struct _EFI_CONSOLE_CTRL_PROTOCOL
+{
+    EFI_STATUS
+    (EFIAPI *GetMode) (struct _EFI_CONSOLE_CTRL_PROTOCOL *this,
+                       EFI_SCREEN_MODE *mode,
+                       BOOLEAN *uga_exists,
+                       BOOLEAN *std_in_locked);
+
+    EFI_STATUS
+    (EFIAPI *SetMode) (struct _EFI_CONSOLE_CTRL_PROTOCOL *this,
+                       EFI_SCREEN_MODE mode);
+
+    EFI_STATUS
+    (EFIAPI *LockStdin) (struct _EFI_CONSOLE_CTRL_PROTOCOL *this,
+                         CHAR16 *password);
+};
+typedef struct _EFI_CONSOLE_CTRL_PROTOCOL EFI_CONSOLE_CTRL_PROTOCOL;
+
+int efi_set_text_mode (int on)
+{
+    EFI_STATUS rc;
+    EFI_CONSOLE_CTRL_PROTOCOL *c;
+    EFI_SCREEN_MODE mode, new_mode;
+    EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+
+    rc = bs->LocateProtocol(&efi_console_ctrl_guid,
+                            NULL,
+                            (void**) &c);
+    if (rc != EFI_SUCCESS)
+    {
+        /* No console control protocol instance available, assume it is
+         * already in text mode. */
+        DBG ("Console control protocol not found, assume text mode.\n");
+        return 1;
+    }
+
+    if (c->GetMode (c, &mode, 0, 0) != EFI_SUCCESS)
+        return 0;
+
+    new_mode = on ? EFI_SCREEN_TEXT : EFI_SCREEN_GRAPHICS;
+    if (mode != new_mode)
+        if (c->SetMode (c, new_mode) != EFI_SUCCESS)
+            return 0;
+
+    return 1;
+}
+
+void efi_cls (void)
+{
+    EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL *conout = efi_systab->ConOut;
+    INT32 orig_attr = conout->Mode->Attribute;
+    conout->SetAttribute (conout, EFI_BLACK);
+    conout->ClearScreen (conout);
+    conout->SetAttribute (conout, orig_attr);
+}

kern/payload.c

@@ -113,7 +113,7 @@ void extract_initrd (void *ptr, size_t len)
 {
     nt_cmdline->bcd_length = BCD_LEN;
     nt_cmdline->bcd = BCD_RAW;
-    printf ("...load BCD @%p %c%c%c%c [%x]\n", BCD_RAW,
+    DBG ("...load BCD @%p %c%c%c%c [%x]\n", BCD_RAW,
             BCD_RAW[0], BCD_RAW[1], BCD_RAW[2], BCD_RAW[3], BCD_LEN);
     vdisk_add_file ("BCD", BCD_RAW, BCD_LEN, read_mem_file);