Re: [kbd] [patch] font: Leverage KD_FONT_OP_GET/SET_TALL font operations

[Alexey Gladkov <legion@kernel.org>]

On Sun, Dec 18, 2022 at 01:33:25AM +0100, Samuel Thibault wrote:
> The new KD_FONT_OP_GET/SET_TALL font operations allow to load fonts taller
> than 32 pixels by dropping the VGA-specific vertical pitch limitation.
> 
> The new maximum font size has thus been raised to 64x128.
> 
> We however continue using the older font operations for smaller fonts, to
> continue supporting older kernels.
> 
> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> 
> Index: kbd-2.5.1/src/compat/linux-kd.h
> ===================================================================
> --- kbd-2.5.1.orig/src/compat/linux-kd.h
> +++ kbd-2.5.1/src/compat/linux-kd.h
> @@ -90,7 +90,8 @@ struct console_font_op {
>  	unsigned int flags; /* KD_FONT_FLAG_* */
>  	unsigned int width, height;
>  	unsigned int charcount;
> -	unsigned char *data; /* font data with height fixed to 32 */
> +	unsigned char *data; /* font data with vpitch fixed to 32 for
> +                              * KD_FONT_OP_SET/GET */
>  };
>  
>  #define KD_FONT_OP_SET 0         /* Set font */
> @@ -98,6 +99,8 @@ struct console_font_op {
>  #define KD_FONT_OP_SET_DEFAULT 2 /* Set font to default, \
>                                      data points to name / NULL */
>  #define KD_FONT_OP_COPY 3        /* Copy from another console */
> +#define KD_FONT_OP_SET_TALL 4    /* Set font with arbitrary vpitch */
> +#define KD_FONT_OP_GET_TALL 5    /* Get font with arbitrary vpitch */
>  
>  #define KD_FONT_FLAG_OLD 0x80000000 /* Invoked via old interface */
>  #define KD_FONT_FLAG_DONT_RECALC 1  /* Don't call adjust_height() */
> Index: kbd-2.5.1/src/libkfont/kdfontop.c
> ===================================================================
> --- kbd-2.5.1.orig/src/libkfont/kdfontop.c
> +++ kbd-2.5.1/src/libkfont/kdfontop.c
> @@ -51,19 +51,33 @@ get_font_kdfontop(struct kfont_context *
>  		unsigned char *buf,
>  		unsigned int *count,
>  		unsigned int *width,
> -		unsigned int *height)
> +		unsigned int *height,
> +		unsigned int *vpitch)
>  {
>  	struct console_font_op cfo;
>  
> +#ifdef KD_FONT_OP_GET_TALL
> +	cfo.op = KD_FONT_OP_GET_TALL;
> +#else
>  	cfo.op = KD_FONT_OP_GET;
> +#endif
>  	cfo.flags = 0;
> -	cfo.width = cfo.height = 32;
> +	cfo.width = 64;
> +	cfo.height = 128;
>  	cfo.charcount = *count;
>  	cfo.data = buf;
>  
> +retry:
>  	errno = 0;
>  
>  	if (ioctl(consolefd, KDFONTOP, &cfo)) {
> +#ifdef KD_FONT_OP_GET_TALL
> +		if (errno == ENOSYS && cfo.op == KD_FONT_OP_GET_TALL) {
> +			/* Kernel before 6.2.  */
> +			cfo.op = KD_FONT_OP_GET;
> +			goto retry;
> +		}
> +#endif
>  		if (errno != ENOSYS && errno != EINVAL) {
>  			KFONT_ERR(ctx, "ioctl(KDFONTOP): %m");
>  			return -1;
> @@ -76,6 +90,14 @@ get_font_kdfontop(struct kfont_context *
>  		*height = cfo.height;
>  	if (width)
>  		*width = cfo.width;
> +	if (vpitch) {
> +#ifdef KD_FONT_OP_GET_TALL
> +		if (cfo.op == KD_FONT_OP_GET_TALL)
> +			*vpitch = cfo.height;
> +		else
> +#endif
> +			*vpitch = 32;
> +	}
>  	return 0;
>  }
>  
> @@ -88,16 +110,17 @@ int
>  kfont_get_font(struct kfont_context *ctx, int fd, unsigned char *buf,
>  		unsigned int *count,
>  		unsigned int *width,
> -		unsigned int *height)
> +		unsigned int *height,
> +		unsigned int *vpitch)
>  {
> -	return get_font_kdfontop(ctx, fd, buf, count, width, height);
> +	return get_font_kdfontop(ctx, fd, buf, count, width, height, vpitch);
>  }
>  
>  int unsigned
>  kfont_get_fontsize(struct kfont_context *ctx, int fd)
>  {
>  	unsigned int count = 0;
> -	if (!kfont_get_font(ctx, fd, NULL, &count, NULL, NULL))
> +	if (!kfont_get_font(ctx, fd, NULL, &count, NULL, NULL, NULL))
>  		return count;
>  	return 256;
>  }
> @@ -106,11 +129,20 @@ static int
>  put_font_kdfontop(struct kfont_context *ctx, int consolefd, unsigned char *buf,
>  		unsigned int count,
>  		unsigned int width,
> -		unsigned int height)
> +		unsigned int height,
> +		unsigned int vpitch)
>  {
>  	struct console_font_op cfo;
>  
> -	cfo.op        = KD_FONT_OP_SET;
> +	if (vpitch == 32 && width <= 32)
> +		cfo.op        = KD_FONT_OP_SET;
> +	else {
> +#ifdef KD_FONT_OP_SET_TALL
> +		cfo.op        = KD_FONT_OP_SET_TALL;
> +#else
> +		return 1;
> +#endif
> +	}
>  	cfo.flags     = 0;
>  	cfo.width     = width;
>  	cfo.height    = height;
> @@ -154,7 +186,7 @@ put_font_kdfontop(struct kfont_context *
>  
>  int
>  kfont_put_font(struct kfont_context *ctx, int fd, unsigned char *buf, unsigned int count,
> -        unsigned int width, unsigned int height)
> +        unsigned int width, unsigned int height, unsigned int vpitch)
>  {
>  	if (!width)
>  		width = 8;
> @@ -162,5 +194,5 @@ kfont_put_font(struct kfont_context *ctx
>  	if (!height)
>  		height = font_charheight(buf, count, width);
>  
> -	return put_font_kdfontop(ctx, fd, buf, count, width, height);
> +	return put_font_kdfontop(ctx, fd, buf, count, width, height, vpitch);
>  }
> Index: kbd-2.5.1/src/libkfont/kfont.h
> ===================================================================
> --- kbd-2.5.1.orig/src/libkfont/kfont.h
> +++ kbd-2.5.1/src/libkfont/kfont.h
> @@ -171,7 +171,8 @@ int kfont_load_unicodemap(struct kfont_c
>   * Sets number of glyphs in COUNT, glyph size in WIDTH and HEIGHT.
>   */
>  int kfont_get_font(struct kfont_context *ctx, int consolefd, unsigned char *buf,
> -		unsigned int *count, unsigned int *width, unsigned int *height)
> +		unsigned int *count, unsigned int *width, unsigned int *height,
> +		unsigned int *vpitch)
>  	__attribute__((nonnull(1)));
>  
>  /*
> @@ -180,7 +181,8 @@ int kfont_get_font(struct kfont_context
>   * Return 0 on success, -1 on failure.
>   */
>  int kfont_put_font(struct kfont_context *ctx, int consolefd, unsigned char *buf,
> -		unsigned int count, unsigned int width, unsigned int height)
> +		unsigned int count, unsigned int width, unsigned int height,
> +		unsigned int vpitch)
>  	__attribute__((nonnull(1)));
>  
>  /*
> @@ -239,7 +241,7 @@ void kfont_disactivatemap(int fd);
>  #include <stdio.h>
>  
>  /* Maximum font size that we try to handle */
> -#define MAXFONTSIZE 65536
> +#define MAXFONTSIZE (512*64*128)
>  
>  /**
>   * readpsffont reads a PSF font.
> Index: kbd-2.5.1/src/libkfont/setfont.c
> ===================================================================
> --- kbd-2.5.1.orig/src/libkfont/setfont.c
> +++ kbd-2.5.1/src/libkfont/setfont.c
> @@ -45,8 +45,9 @@ findpartialfont(struct kfont_context *ct
>  static int erase_mode = 1;
>  
>  static int
> -do_loadfont(struct kfont_context *ctx, int fd, const unsigned char *inbuf,
> -		unsigned int width, unsigned int height, unsigned int hwunit,
> +try_loadfont(struct kfont_context *ctx, int fd, const unsigned char *inbuf,
> +		unsigned int width, unsigned int height, unsigned int vpitch,
> +		unsigned int hwunit,
>  		unsigned int fontsize, const char *filename)
>  {
>  	unsigned char *buf = NULL;
> @@ -54,13 +55,13 @@ do_loadfont(struct kfont_context *ctx, i
>  	int bad_video_erase_char = 0;
>  	int ret;
>  
> -	if (height < 1 || height > 32) {
> -		KFONT_ERR(ctx, _("Bad character height %d"), height);
> +	if (height < 1 || height > 64) {
> +		KFONT_ERR(ctx, _("Bad character height %d (limit is 64)"), height);

Hm. But max_font_height is 128. Shouldn't it be height > 128 ?

>  		return -EX_DATAERR;
>  	}
>  
> -	if (width < 1 || width > 32) {
> -		KFONT_ERR(ctx, _("Bad character width %d"), width);
> +	if (width < 1 || width > 128) {
> +		KFONT_ERR(ctx, _("Bad character width %d (limit is 128)"), width);

Same here. max_font_width is 64.

>  		return -EX_DATAERR;
>  	}
>  
> @@ -68,8 +69,8 @@ do_loadfont(struct kfont_context *ctx, i
>  		hwunit = height;
>  
>  	if ((ctx->options & (1 << kfont_double_size)) &&
> -	    (height > 16 || width > 16)) {
> -		KFONT_ERR(ctx, _("Cannot double %dx%d font (limit is 16x16)"), width, height);
> +	    (height > 32 || width > 64)) {
> +		KFONT_ERR(ctx, _("Cannot double %dx%d font (limit is 32x64)"), width, height);
>  		kfont_unset_option(ctx, kfont_double_size);
>  	}
>  
> @@ -78,7 +79,7 @@ do_loadfont(struct kfont_context *ctx, i
>  		unsigned int kbytewidth = (2 * width + 7) / 8;
>  		unsigned int charsize   = height * bytewidth;
>  
> -		kcharsize = 32 * kbytewidth;
> +		kcharsize = vpitch * kbytewidth;
>  		buflen    = kcharsize * ((fontsize < 128) ? 128 : fontsize);
>  
>  		buf = calloc(1, buflen);
> @@ -112,7 +113,7 @@ do_loadfont(struct kfont_context *ctx, i
>  		unsigned int bytewidth = (width + 7) / 8;>  		unsigned int charsize  = height * bytewidth;
>  
> -		kcharsize = 32 * bytewidth;
> +		kcharsize = vpitch * bytewidth;
>  		buflen    = kcharsize * ((fontsize < 128) ? 128 : fontsize);
>  
>  		buf = calloc(1, buflen);
> @@ -169,7 +170,7 @@ do_loadfont(struct kfont_context *ctx, i
>  		KFONT_INFO(ctx, _("Loading %d-char %dx%d (%d) font"),
>  		       fontsize, width, height, hwunit);
>  
> -	if (kfont_put_font(ctx, fd, buf, fontsize, width, hwunit) < 0) {
> +	if (kfont_put_font(ctx, fd, buf, fontsize, width, hwunit, vpitch) < 1) {
>  		ret = -EX_OSERR;
>  		goto err;
>  	}
> @@ -181,6 +182,20 @@ err:
>  }
>  
>  static int
> +do_loadfont(struct kfont_context *ctx, int fd, const unsigned char *inbuf,
> +		unsigned int width, unsigned int height, unsigned int hwunit,
> +		unsigned int fontsize, const char *filename)
> +{
> +	int ret;
> +
> +	if (height <= 32 && width <= 32)
> +		/* This can work with pre-6.2 kernels and its size and vpitch limitations */
> +		return try_loadfont(ctx, fd, inbuf, width, height, 32, hwunit, fontsize, filename);
> +	else
> +		return try_loadfont(ctx, fd, inbuf, width, height, height, hwunit, fontsize, filename);
> +}
> +
> +static int
>  do_loadtable(struct kfont_context *ctx, int fd, struct unicode_list *uclistheads,
>  		unsigned int fontsize)
>  {
> @@ -585,19 +600,19 @@ save_font(struct kfont_context *ctx, int
>  /* this is the max font size the kernel is willing to handle */
>  	unsigned char buf[MAXFONTSIZE];
>  
> -	unsigned int i, ct, width, height, bytewidth, charsize, kcharsize;
> +	unsigned int i, ct, width, height, bytewidth, charsize, kcharsize, vpitch;
>  	int ret;
>  
> -	ct = sizeof(buf) / (32 * 32 / 8); /* max size 32x32, 8 bits/byte */
> +	ct = sizeof(buf) / (64 * 128 / 8); /* max size 64x128, 8 bits/byte */
>  
> -	if (kfont_get_font(ctx, consolefd, buf, &ct, &width, &height) < 0)
> +	if (kfont_get_font(ctx, consolefd, buf, &ct, &width, &height, &vpitch) < 0)
>  		return -EX_OSERR;
>  
>  	/* save as efficiently as possible */
>  	bytewidth = (width + 7) / 8;
>  	height    = font_charheight(buf, ct, width);
>  	charsize  = height * bytewidth;
> -	kcharsize = 32 * bytewidth;
> +	kcharsize = vpitch * bytewidth;
>  
>  /* Do we need a psf header? */
>  /* Yes if ct==512 - otherwise we cannot distinguish
> Index: kbd-2.5.1/src/showconsolefont.c
> ===================================================================
> --- kbd-2.5.1.orig/src/showconsolefont.c
> +++ kbd-2.5.1/src/showconsolefont.c
> @@ -205,7 +205,7 @@ int main(int argc, char **argv)
>  	if (info) {
>  		nr = rows = cols = 0;
>  
> -		ret = kfont_get_font(kfont, fd, NULL, &nr, &rows, &cols);
> +		ret = kfont_get_font(kfont, fd, NULL, &nr, &rows, &cols, NULL);
>  		if (ret != 0)
>  			leave(kfont, EXIT_FAILURE);
>  
> Index: kbd-2.5.1/tests/libtswrap/ioctl.c
> ===================================================================
> --- kbd-2.5.1.orig/tests/libtswrap/ioctl.c
> +++ kbd-2.5.1/tests/libtswrap/ioctl.c
> @@ -93,6 +93,12 @@ static struct translate_names kd_font_op
>  	{ KD_FONT_OP_GET, "KD_FONT_OP_GET" },
>  	{ KD_FONT_OP_SET_DEFAULT, "KD_FONT_OP_SET_DEFAULT" },
>  	{ KD_FONT_OP_COPY, "KD_FONT_OP_COPY" },
> +#ifdef KD_FONT_OP_SET_TALL
> +	{ KD_FONT_OP_SET_TALL, "KD_FONT_OP_SET_TALL" },
> +#endif
> +#ifdef KD_FONT_OP_GET_TALL
> +	{ KD_FONT_OP_GET_TALL, "KD_FONT_OP_GET_TALL" },
> +#endif
>  	{ 0, NULL }
>  };
>  
> 
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-- 
Rgrds, legion