linux-kernel - [PATCH v2 25/47] tty: vt: sanitize consw::con

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Message-ID: <20240122110401.7289-26-jirislaby@kernel.org>
Date: Mon, 22 Jan 2024 12:03:39 +0100
From: "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To: gregkh@...uxfoundation.org
Cc: linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"Jiri Slaby (SUSE)" <jirislaby@...nel.org>,
	Helge Deller <deller@....de>,
	linux-fbdev@...r.kernel.org,
	dri-devel@...ts.freedesktop.org
Subject: [PATCH v2 25/47] tty: vt: sanitize consw::con_putc() parameters

Make parameters of consw::con_putc() saner:
* x and y are unsigned now, as they cannot be negative, and
* ca is made u16, as it is composed of two 8bit values (character and
  attribute). See the con_putcs() hook, u16/ushort is worked on there.

And document the hook.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
Cc: Helge Deller <deller@....de>
Cc: linux-fbdev@...r.kernel.org
Cc: dri-devel@...ts.freedesktop.org
---
 drivers/video/console/dummycon.c    | 6 ++++--
 drivers/video/console/newport_con.c | 4 ++--
 include/linux/console.h             | 5 ++++-
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c
index 0a69d5c216ee..1874beed0325 100644
--- a/drivers/video/console/dummycon.c
+++ b/drivers/video/console/dummycon.c
@@ -50,7 +50,8 @@ void dummycon_unregister_output_notifier(struct notifier_block *nb)
 	raw_notifier_chain_unregister(&dummycon_output_nh, nb);
 }
 
-static void dummycon_putc(struct vc_data *vc, int c, int ypos, int xpos)
+static void dummycon_putc(struct vc_data *vc, u16 c, unsigned int y,
+                          unsigned int x)
 {
 	WARN_CONSOLE_UNLOCKED();
 
@@ -84,7 +85,8 @@ static int dummycon_blank(struct vc_data *vc, int blank, int mode_switch)
 	return 1;
 }
 #else
-static void dummycon_putc(struct vc_data *vc, int c, int ypos, int xpos) { }
+static void dummycon_putc(struct vc_data *vc, u16 c, unsigned int y,
+			  unsigned int x) { }
 static void dummycon_putcs(struct vc_data *vc, const unsigned short *s,
 			   int count, int ypos, int xpos) { }
 static int dummycon_blank(struct vc_data *vc, int blank, int mode_switch)
diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index 55c6106b3507..9b5c0118873e 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -367,8 +367,8 @@ static void newport_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
 	}
 }
 
-static void newport_putc(struct vc_data *vc, int charattr, int ypos,
-			 int xpos)
+static void newport_putc(struct vc_data *vc, u16 charattr, unsigned int ypos,
+			 unsigned int xpos)
 {
 	unsigned char *p;
 
diff --git a/include/linux/console.h b/include/linux/console.h
index 8fd96a5fca5f..92d57e5b3009 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -39,6 +39,8 @@ enum vc_intensity;
  * @con_init:   initialize the console on @vc. @init is true for the very first
  *		call on this @vc.
  * @con_clear:  erase @count characters at [@x, @y] on @vc. @count >= 1.
+ * @con_putc:   emit one character with attributes @ca to [@x, @y] on @vc.
+ *		(optional -- @con_putcs would be called instead)
  * @con_scroll: move lines from @top to @bottom in direction @dir by @lines.
  *		Return true if no generic handling should be done.
  *		Invoked by csi_M and printing to the console.
@@ -53,7 +55,8 @@ struct consw {
 	void	(*con_deinit)(struct vc_data *vc);
 	void	(*con_clear)(struct vc_data *vc, unsigned int y,
 			     unsigned int x, unsigned int count);
-	void	(*con_putc)(struct vc_data *vc, int c, int ypos, int xpos);
+	void	(*con_putc)(struct vc_data *vc, u16 ca, unsigned int y,
+			    unsigned int x);
 	void	(*con_putcs)(struct vc_data *vc, const unsigned short *s,
 			int count, int ypos, int xpos);
 	void	(*con_cursor)(struct vc_data *vc, int mode);
-- 
2.43.0