libpayload: video: Check for 'console' pointer before dereferencing it

Seems that the 'if (cursor_enabled)' check in
video_console_fixup_cursor() that was removed in chromium.org 1f880bca0 really
meant to check for 'if (console)'. Looks like the whole video console
driver is built extra robust to not fail no matter how screwed up the
console is, so let's add this missing check here as well. Also fixed up
a few other missing 'if (!console)' checks while I'm at it.

However, what payloads should really be doing is check the return value
of video_(console_)init() and not call the other video functions if that
failed. This also adapts video_console_init() to correctly pass through
the return value for that purpose (something that seems to have been
overlooked in the dd9e4e58 refactoring).

BUG=chrome-os-partner:28494
TEST=None. I don't know what Dave did to trigger this in the first
place, but it's pretty straight-forward.

Original-Change-Id: I1b9f09d49dc70dacf20621b19e081c754d4814f7
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/200688
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit 3f01d1dc0974774f0b3ba5fc4e069978f266f2fc)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I98c1d8360539b457e6df07cbcf799acaf6c4631b
Reviewed-on: http://review.coreboot.org/7910
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Tested-by: build bot (Jenkins)

1 files changed, 15 insertions, 13 deletions

diff --git a/payloads/libpayload/drivers/video/video.c b/payloads/libpayload/drivers/video/video.c
index 318548ba3a..5f76a3075a 100644
--- a/payloads/libpayload/drivers/video/video.c
+++ b/payloads/libpayload/drivers/video/video.c
@@ -73,6 +73,9 @@ void video_get_rows_cols(unsigned int *rows, unsigned int *cols)
 
 static void video_console_fixup_cursor(void)
 {
+	if (!console)
+		return;
+
 	if (cursorx < 0)
 		cursorx = 0;
 
@@ -89,7 +92,7 @@ static void video_console_fixup_cursor(void)
 		cursory--;
 	}
 
-	if (console && console->set_cursor)
+	if (console->set_cursor)
 		console->set_cursor(cursorx, cursory);
 }
 
@@ -119,6 +122,9 @@ void video_console_putc(u8 row, u8 col, unsigned int ch)
 
 void video_console_putchar(unsigned int ch)
 {
+	if (!console)
+		return;
+
 	/* replace black-on-black with light-gray-on-black.
 	 * do it here, instead of in libc/console.c
 	 */
@@ -145,16 +151,11 @@ void video_console_putchar(unsigned int ch)
 		break;
 
 	case '\t':
-		while(cursorx % 8 && cursorx < console->columns) {
-			if (console)
-				console->putc(cursory, cursorx, (ch & 0xFF00) | ' ');
-
-			cursorx++;
-		}
+		while(cursorx % 8 && cursorx < console->columns)
+			console->putc(cursory, cursorx++, (ch & 0xFF00) | ' ');
 		break;
 	default:
-		if (console)
-			console->putc(cursory, cursorx++, ch);
+		console->putc(cursory, cursorx++, ch);
 		break;
 	}
 
@@ -167,7 +168,7 @@ void video_console_get_cursor(unsigned int *x, unsigned int *y, unsigned int *en
 	*y=0;
 	*en=0;
 
-	if (console->get_cursor)
+	if (console && console->get_cursor)
 		console->get_cursor(x, y, en);
 
 	*x = cursorx;
@@ -214,9 +215,10 @@ int video_init(void)
 
 int video_console_init(void)
 {
-	video_init();
-	if (console)
-		console_add_output_driver(&cons);
+	int ret = video_init();
+	if (ret)
+		return ret;
+	console_add_output_driver(&cons);
 	return 0;
 }