tty: vt: sanitize arguments of consw::con_clear()

In consw::con_clear():
* Height is always 1, so drop it.
* Offsets and width are always unsigned values, so re-type them as such.

This needs a new __fbcon_clear() in the fbcon code to still handle
height which might not be 1 when called internally.

Note that tests for negative count/width are left in place -- they are
taken care of in the next patches.

And document the hook.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-parisc@vger.kernel.org
Tested-by: Helge Deller <deller@gmx.de> # parisc STI console
Link: https://lore.kernel.org/r/20240122110401.7289-22-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5 files changed, 16 insertions, 21 deletions

diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c
index f2cef9d9a4b5..0a69d5c216ee 100644
--- a/drivers/video/console/dummycon.c
+++ b/drivers/video/console/dummycon.c
@@ -109,8 +109,8 @@ static void dummycon_init(struct vc_data *vc, bool init)
 }
 
 static void dummycon_deinit(struct vc_data *vc) { }
-static void dummycon_clear(struct vc_data *vc, int sy, int sx, int height,
-			   int width) { }
+static void dummycon_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
+			   unsigned int width) { }
 static void dummycon_cursor(struct vc_data *vc, int mode) { }
 
 static bool dummycon_scroll(struct vc_data *vc, unsigned int top,
diff --git a/drivers/video/console/mdacon.c b/drivers/video/console/mdacon.c
index c5b255c96879..1ddbb6cd5b0c 100644
--- a/drivers/video/console/mdacon.c
+++ b/drivers/video/console/mdacon.c
@@ -442,23 +442,18 @@ static void mdacon_putcs(struct vc_data *c, const unsigned short *s,
 	}
 }
 
-static void mdacon_clear(struct vc_data *c, int y, int x, 
-			  int height, int width)
+static void mdacon_clear(struct vc_data *c, unsigned int y, unsigned int x,
+			 unsigned int width)
 {
 	u16 *dest = mda_addr(x, y);
 	u16 eattr = mda_convert_attr(c->vc_video_erase_char);
 
-	if (width <= 0 || height <= 0)
+	if (width <= 0)
 		return;
 
-	if (x==0 && width==mda_num_columns) {
-		scr_memsetw(dest, eattr, height*width*2);
-	} else {
-		for (; height > 0; height--, dest+=mda_num_columns)
-			scr_memsetw(dest, eattr, width*2);
-	}
+	scr_memsetw(dest, eattr, width * 2);
 }
-                        
+
 static int mdacon_switch(struct vc_data *c)
 {
 	return 1;	/* redrawing needed */
diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index 12c64ef47087..55c6106b3507 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -346,12 +346,12 @@ static void newport_deinit(struct vc_data *c)
 	}
 }
 
-static void newport_clear(struct vc_data *vc, int sy, int sx, int height,
-			  int width)
+static void newport_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
+			  unsigned int width)
 {
 	int xend = ((sx + width) << 3) - 1;
 	int ystart = ((sy << 4) + topscan) & 0x3ff;
-	int yend = (((sy + height) << 4) + topscan - 1) & 0x3ff;
+	int yend = (((sy + 1) << 4) + topscan - 1) & 0x3ff;
 
 	if (logo_active)
 		return;
diff --git a/drivers/video/console/sticon.c b/drivers/video/console/sticon.c
index 0bfeabc3f7c7..d99c2a659bfd 100644
--- a/drivers/video/console/sticon.c
+++ b/drivers/video/console/sticon.c
@@ -300,13 +300,13 @@ static void sticon_deinit(struct vc_data *c)
 	sticon_set_def_font(i);
 }
 
-static void sticon_clear(struct vc_data *conp, int sy, int sx, int height,
-			 int width)
+static void sticon_clear(struct vc_data *conp, unsigned int sy, unsigned int sx,
+			 unsigned int width)
 {
-    if (!height || !width)
+    if (!width)
 	return;
 
-    sti_clear(sticon_sti, sy, sx, height, width,
+    sti_clear(sticon_sti, sy, sx, 1, width,
 	      conp->vc_video_erase_char, font_data[conp->vc_num]);
 }
 
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 5d523753def8..85f29dec2c3d 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -1191,8 +1191,8 @@ static bool vgacon_scroll(struct vc_data *c, unsigned int t, unsigned int b,
  *  The console `switch' structure for the VGA based console
  */
 
-static void vgacon_clear(struct vc_data *vc, int sy, int sx, int height,
-			 int width) { }
+static void vgacon_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
+			 unsigned int width) { }
 static void vgacon_putc(struct vc_data *vc, int c, int ypos, int xpos) { }
 static void vgacon_putcs(struct vc_data *vc, const unsigned short *s,
 			 int count, int ypos, int xpos) { }