Re: [PATCH v3 2/2] VT: Allow to get max font width and height

[Helge Deller <deller@gmx.de>]

On 3/12/24 15:23, legion@kernel.org wrote:
> From: Alexey Gladkov <legion@kernel.org>
>
> The Console drivers has more restrictive font size limits than vt_ioctl.
> This leads to errors that are difficult to handle. If a font whose size
> is not supported is used, an EINVAL error will be returned, which is
> also returned in case of errors in the font itself. At the moment there
> is no way to understand what font sizes the current console driver
> supports.
>
> To solve this problem, we need to transfer information about the
> supported font to userspace from the console driver.
>
> Signed-off-by: Alexey Gladkov <legion@kernel.org>

Acked-by: Helge Deller <deller@gmx.de>

Helge


> ---
>   drivers/video/console/newport_con.c | 21 +++++++++++++++++----
>   drivers/video/console/sticon.c      | 25 +++++++++++++++++++++++--
>   drivers/video/console/vgacon.c      | 21 ++++++++++++++++++++-
>   drivers/video/fbdev/core/fbcon.c    | 22 +++++++++++++++++++++-
>   4 files changed, 81 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
> index e8e4f82cd4a1..87f174a95fa8 100644
> --- a/drivers/video/console/newport_con.c
> +++ b/drivers/video/console/newport_con.c
> @@ -33,6 +33,9 @@
>
>   #define NEWPORT_LEN	0x10000
>
> +#define NEWPORT_MAX_FONT_WIDTH 8
> +#define NEWPORT_MAX_FONT_HEIGHT 16
> +
>   #define FONT_DATA ((unsigned char *)font_vga_8x16.data)
>
>   static unsigned char *font_data[MAX_NR_CONSOLES];
> @@ -328,8 +331,8 @@ static void newport_init(struct vc_data *vc, int init)
>   {
>   	int cols, rows;
>
> -	cols = newport_xsize / 8;
> -	rows = newport_ysize / 16;
> +	cols = newport_xsize / NEWPORT_MAX_FONT_WIDTH;
> +	rows = newport_ysize / NEWPORT_MAX_FONT_HEIGHT;
>   	vc->vc_can_do_color = 1;
>   	if (init) {
>   		vc->vc_cols = cols;
> @@ -507,8 +510,8 @@ static int newport_set_font(int unit, struct console_font *op, unsigned int vpit
>
>   	/* ladis: when I grow up, there will be a day... and more sizes will
>   	 * be supported ;-) */
> -	if ((w != 8) || (h != 16) || (vpitch != 32)
> -	    || (op->charcount != 256 && op->charcount != 512))
> +	if ((w != NEWPORT_MAX_FONT_WIDTH) || (h != NEWPORT_MAX_FONT_HEIGHT) ||
> +	    (vpitch != 32) || (op->charcount != 256 && op->charcount != 512))
>   		return -EINVAL;
>
>   	if (!(new_data = kmalloc(FONT_EXTRA_WORDS * sizeof(int) + size,
> @@ -569,6 +572,15 @@ static int newport_font_default(struct vc_data *vc, struct console_font *op, cha
>   	return newport_set_def_font(vc->vc_num, op);
>   }
>
> +static int newport_font_info(struct vc_data *vc, struct console_font_info *info)
> +{
> +	info->min_width = info->max_width = NEWPORT_MAX_FONT_WIDTH;
> +	info->min_height = info->max_height = NEWPORT_MAX_FONT_HEIGHT;
> +	info->flags = KD_FONT_INFO_FLAG_LOW_SIZE | KD_FONT_INFO_FLAG_HIGH_SIZE;
> +
> +	return 0;
> +}
> +
>   static int newport_font_set(struct vc_data *vc, struct console_font *font,
>   			    unsigned int vpitch, unsigned int flags)
>   {
> @@ -688,6 +700,7 @@ const struct consw newport_con = {
>   	.con_scroll	  = newport_scroll,
>   	.con_switch	  = newport_switch,
>   	.con_blank	  = newport_blank,
> +	.con_font_info	  = newport_font_info,
>   	.con_font_set	  = newport_font_set,
>   	.con_font_default = newport_font_default,
>   	.con_save_screen  = newport_save_screen
> diff --git a/drivers/video/console/sticon.c b/drivers/video/console/sticon.c
> index 992a4fa431aa..d32ca458eb77 100644
> --- a/drivers/video/console/sticon.c
> +++ b/drivers/video/console/sticon.c
> @@ -56,6 +56,11 @@
>   #define BLANK 0
>   static int vga_is_gfx;
>
> +#define STICON_MIN_FONT_WIDTH 6
> +#define STICON_MIN_FONT_HEIGHT 6
> +#define STICON_MAX_FONT_WIDTH 32
> +#define STICON_MAX_FONT_HEIGHT 32
> +
>   #define STI_DEF_FONT	sticon_sti->font
>
>   /* borrowed from fbcon.c */
> @@ -180,8 +185,10 @@ static int sticon_set_font(struct vc_data *vc, struct console_font *op,
>   	struct sti_cooked_font *cooked_font;
>   	unsigned char *data = op->data, *p;
>
> -	if ((w < 6) || (h < 6) || (w > 32) || (h > 32) || (vpitch != 32)
> -	    || (op->charcount != 256 && op->charcount != 512))
> +	if (!in_range(w, STICON_MIN_FONT_WIDTH, STICON_MAX_FONT_WIDTH) ||
> +	    !in_range(h, STICON_MIN_FONT_HEIGHT, STICON_MAX_FONT_HEIGHT) ||
> +	    (vpitch != 32) ||
> +	    (op->charcount != 256 && op->charcount != 512))
>   		return -EINVAL;
>   	pitch = ALIGN(w, 8) / 8;
>   	bpc = pitch * h;
> @@ -273,6 +280,19 @@ static int sticon_font_set(struct vc_data *vc, struct console_font *font,
>   	return sticon_set_font(vc, font, vpitch);
>   }
>
> +static int sticon_font_info(struct vc_data *vc, struct console_font_info *info)
> +{
> +	info->min_width = STICON_MIN_FONT_WIDTH;
> +	info->min_height = STICON_MIN_FONT_HEIGHT;
> +
> +	info->max_width = STICON_MAX_FONT_WIDTH;
> +	info->max_height = STICON_MAX_FONT_HEIGHT;
> +
> +	info->flags = KD_FONT_INFO_FLAG_LOW_SIZE | KD_FONT_INFO_FLAG_HIGH_SIZE;
> +
> +	return 0;
> +}
> +
>   static void sticon_init(struct vc_data *c, int init)
>   {
>       struct sti_struct *sti = sticon_sti;
> @@ -371,6 +391,7 @@ static const struct consw sti_con = {
>   	.con_scroll		= sticon_scroll,
>   	.con_switch		= sticon_switch,
>   	.con_blank		= sticon_blank,
> +	.con_font_info		= sticon_font_info,
>   	.con_font_set		= sticon_font_set,
>   	.con_font_default	= sticon_font_default,
>   	.con_build_attr		= sticon_build_attr,
> diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
> index 8ef1579fa57f..b75d31ef3353 100644
> --- a/drivers/video/console/vgacon.c
> +++ b/drivers/video/console/vgacon.c
> @@ -61,6 +61,10 @@ static struct vgastate vgastate;
>   #define BLANK 0x0020
>
>   #define VGA_FONTWIDTH       8   /* VGA does not support fontwidths != 8 */
> +
> +#define VGACON_MAX_FONT_WIDTH VGA_FONTWIDTH
> +#define VGACON_MAX_FONT_HEIGHT 32
> +
>   /*
>    *  Interface used by the world
>    */
> @@ -1013,6 +1017,19 @@ static int vgacon_adjust_height(struct vc_data *vc, unsigned fontheight)
>   	return 0;
>   }
>
> +static int vgacon_font_info(struct vc_data *vc, struct console_font_info *info)
> +{
> +	info->min_width = VGACON_MAX_FONT_WIDTH;
> +	info->min_height = 0;
> +
> +	info->max_width = VGACON_MAX_FONT_WIDTH;
> +	info->max_height = VGACON_MAX_FONT_HEIGHT;
> +
> +	info->flags = KD_FONT_INFO_FLAG_LOW_SIZE | KD_FONT_INFO_FLAG_HIGH_SIZE;
> +
> +	return 0;
> +}
> +
>   static int vgacon_font_set(struct vc_data *c, struct console_font *font,
>   			   unsigned int vpitch, unsigned int flags)
>   {
> @@ -1022,7 +1039,8 @@ static int vgacon_font_set(struct vc_data *c, struct console_font *font,
>   	if (vga_video_type < VIDEO_TYPE_EGAM)
>   		return -EINVAL;
>
> -	if (font->width != VGA_FONTWIDTH || font->height > 32 || vpitch != 32 ||
> +	if (font->width != VGACON_MAX_FONT_WIDTH ||
> +	    font->height > VGACON_MAX_FONT_HEIGHT || vpitch != 32 ||
>   	    (charcount != 256 && charcount != 512))
>   		return -EINVAL;
>
> @@ -1177,6 +1195,7 @@ const struct consw vga_con = {
>   	.con_scroll = vgacon_scroll,
>   	.con_switch = vgacon_switch,
>   	.con_blank = vgacon_blank,
> +	.con_font_info = vgacon_font_info,
>   	.con_font_set = vgacon_font_set,
>   	.con_font_get = vgacon_font_get,
>   	.con_resize = vgacon_resize,
> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> index 46823c2e2ba1..e10abe416159 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -101,6 +101,9 @@ enum {
>   	FBCON_LOGO_DONTSHOW	= -3	/* do not show the logo */
>   };
>
> +#define FBCON_MAX_FONT_WIDTH 32
> +#define FBCON_MAX_FONT_HEIGHT 32
> +
>   static struct fbcon_display fb_display[MAX_NR_CONSOLES];
>
>   static struct fb_info *fbcon_registered_fb[FB_MAX];
> @@ -2456,6 +2459,21 @@ static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
>   	return ret;
>   }
>
> +
> +static int fbcon_font_info(struct vc_data *vc, struct console_font_info *info)
> +{
> +	info->min_width = 0;
> +	info->min_height = 0;
> +
> +	info->max_width = FBCON_MAX_FONT_WIDTH;
> +	info->max_height = FBCON_MAX_FONT_HEIGHT;
> +
> +	info->flags = KD_FONT_INFO_FLAG_LOW_SIZE | KD_FONT_INFO_FLAG_HIGH_SIZE;
> +
> +	return 0;
> +}
> +
> +
>   /*
>    *  User asked to set font; we are guaranteed that charcount does not exceed 512
>    *  but lets not assume that, since charcount of 512 is small for unicode support.
> @@ -2483,7 +2501,8 @@ static int fbcon_set_font(struct vc_data *vc, struct console_font *font,
>   	    h > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres))
>   		return -EINVAL;
>
> -	if (font->width > 32 || font->height > 32)
> +	if (font->width > FBCON_MAX_FONT_WIDTH ||
> +	    font->height > FBCON_MAX_FONT_HEIGHT)
>   		return -EINVAL;
>
>   	/* Make sure drawing engine can handle the font */
> @@ -3158,6 +3177,7 @@ static const struct consw fb_con = {
>   	.con_scroll 		= fbcon_scroll,
>   	.con_switch 		= fbcon_switch,
>   	.con_blank 		= fbcon_blank,
> +	.con_font_info 		= fbcon_font_info,
>   	.con_font_set 		= fbcon_set_font,
>   	.con_font_get 		= fbcon_get_font,
>   	.con_font_default	= fbcon_set_def_font,