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fbcon: Avoid using FNTCHARCNT() and hard-coded built-in font charcount
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For user-provided fonts, the framebuffer layer is using a magic
negative-indexing macro, FNTCHARCNT(), to keep track of their number of
characters:

	#define FNTCHARCNT(fd)	(((int *)(fd))[-3])

For built-in fonts, it is using hard-coded values (256). This results in
something like the following:

		map.length = (ops->p->userfont) ?
			FNTCHARCNT(ops->p->fontdata) : 256;

This is unsatisfactory. In fact, there is already a `charcount` field in
our virtual console descriptor (see `struct console_font` inside `struct
vc_data`), let us use it:

		map.length = vc->vc_font.charcount;

Recently we added a `charcount` field to `struct font_desc`. Use it to set
`vc->vc_font.charcount` properly. The idea is:

  - We only use FNTCHARCNT() on `vc->vc_font.data` and `p->fontdata`.
    Assume FNTCHARCNT() is working as intended;
  - Whenever `vc->vc_font.data` is set, also set `vc->vc_font.charcount`
    properly;
  - We can now replace `FNTCHARCNT(vc->vc_font.data)` with
    `vc->vc_font.charcount`;
  - Since `p->fontdata` always point to the same font data buffer with
    `vc->vc_font.data`, we can also replace `FNTCHARCNT(p->fontdata)` with
    `vc->vc_font.charcount`.

In conclusion, set `vc->vc_font.charcount` properly in fbcon_startup(),
fbcon_init(), fbcon_set_disp() and fbcon_do_set_font(), then replace
FNTCHARCNT() with `vc->vc_font.charcount`. No more if-else between
negative-indexing macros and hard-coded values.

Do not include <linux/font.h> in fbcon_rotate.c and tileblit.c, since they
no longer need it.

Depends on patch "Fonts: Add charcount field to font_desc".

Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/e460a5780e54e3022661d5f09555144583b4cc59.1605169912.git.yepeilin.cs@gmail.com
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@ypl-coffee @danvet
ypl-coffee authored and danvet committed Nov 16, 2020
1 parent 4497364 commit a1ac250
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Showing 3 changed files with 23 additions and 41 deletions.
57 changes: 21 additions & 36 deletions drivers/video/fbdev/core/fbcon.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1004,7 +1004,7 @@ static const char *fbcon_startup(void)
vc->vc_font.width = font->width;
vc->vc_font.height = font->height;
vc->vc_font.data = (void *)(p->fontdata = font->data);
vc->vc_font.charcount = 256; /* FIXME Need to support more fonts */
vc->vc_font.charcount = font->charcount;
} else {
p->fontdata = vc->vc_font.data;
}
Expand Down Expand Up @@ -1032,7 +1032,7 @@ static void fbcon_init(struct vc_data *vc, int init)
struct vc_data **default_mode = vc->vc_display_fg;
struct vc_data *svc = *default_mode;
struct fbcon_display *t, *p = &fb_display[vc->vc_num];
int logo = 1, new_rows, new_cols, rows, cols, charcnt = 256;
int logo = 1, new_rows, new_cols, rows, cols;
int cap, ret;

if (WARN_ON(info_idx == -1))
Expand Down Expand Up @@ -1068,6 +1068,7 @@ static void fbcon_init(struct vc_data *vc, int init)
fvc->vc_font.data);
vc->vc_font.width = fvc->vc_font.width;
vc->vc_font.height = fvc->vc_font.height;
vc->vc_font.charcount = fvc->vc_font.charcount;
p->userfont = t->userfont;

if (p->userfont)
Expand All @@ -1083,17 +1084,13 @@ static void fbcon_init(struct vc_data *vc, int init)
vc->vc_font.width = font->width;
vc->vc_font.height = font->height;
vc->vc_font.data = (void *)(p->fontdata = font->data);
vc->vc_font.charcount = 256; /* FIXME Need to
support more fonts */
vc->vc_font.charcount = font->charcount;
}
}

if (p->userfont)
charcnt = FNTCHARCNT(p->fontdata);

vc->vc_can_do_color = (fb_get_color_depth(&info->var, &info->fix)!=1);
vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;
if (charcnt == 256) {
if (vc->vc_font.charcount == 256) {
vc->vc_hi_font_mask = 0;
} else {
vc->vc_hi_font_mask = 0x100;
Expand Down Expand Up @@ -1358,7 +1355,7 @@ static void fbcon_set_disp(struct fb_info *info, struct fb_var_screeninfo *var,
struct vc_data **default_mode, *vc;
struct vc_data *svc;
struct fbcon_ops *ops = info->fbcon_par;
int rows, cols, charcnt = 256;
int rows, cols;

p = &fb_display[unit];

Expand All @@ -1378,12 +1375,11 @@ static void fbcon_set_disp(struct fb_info *info, struct fb_var_screeninfo *var,
vc->vc_font.data = (void *)(p->fontdata = t->fontdata);
vc->vc_font.width = (*default_mode)->vc_font.width;
vc->vc_font.height = (*default_mode)->vc_font.height;
vc->vc_font.charcount = (*default_mode)->vc_font.charcount;
p->userfont = t->userfont;
if (p->userfont)
REFCOUNT(p->fontdata)++;
}
if (p->userfont)
charcnt = FNTCHARCNT(p->fontdata);

var->activate = FB_ACTIVATE_NOW;
info->var.activate = var->activate;
Expand All @@ -1393,7 +1389,7 @@ static void fbcon_set_disp(struct fb_info *info, struct fb_var_screeninfo *var,
ops->var = info->var;
vc->vc_can_do_color = (fb_get_color_depth(&info->var, &info->fix)!=1);
vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;
if (charcnt == 256) {
if (vc->vc_font.charcount == 256) {
vc->vc_hi_font_mask = 0;
} else {
vc->vc_hi_font_mask = 0x100;
Expand Down Expand Up @@ -2027,7 +2023,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
*/
if (pitch <= 0)
return -EINVAL;
size = CALC_FONTSZ(vc->vc_font.height, pitch, FNTCHARCNT(vc->vc_font.data));
size = CALC_FONTSZ(vc->vc_font.height, pitch, vc->vc_font.charcount);
if (size > FNTSIZE(vc->vc_font.data))
return -EINVAL;
}
Expand Down Expand Up @@ -2075,7 +2071,7 @@ static int fbcon_switch(struct vc_data *vc)
struct fbcon_ops *ops;
struct fbcon_display *p = &fb_display[vc->vc_num];
struct fb_var_screeninfo var;
int i, ret, prev_console, charcnt = 256;
int i, ret, prev_console;

info = registered_fb[con2fb_map[vc->vc_num]];
ops = info->fbcon_par;
Expand Down Expand Up @@ -2152,10 +2148,7 @@ static int fbcon_switch(struct vc_data *vc)
vc->vc_can_do_color = (fb_get_color_depth(&info->var, &info->fix)!=1);
vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;

if (p->userfont)
charcnt = FNTCHARCNT(vc->vc_font.data);

if (charcnt > 256)
if (vc->vc_font.charcount > 256)
vc->vc_complement_mask <<= 1;

updatescrollmode(p, info, vc);
Expand Down Expand Up @@ -2405,31 +2398,27 @@ static void set_vc_hi_font(struct vc_data *vc, bool set)
}
}

static int fbcon_do_set_font(struct vc_data *vc, int w, int h,
static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
const u8 * data, int userfont)
{
struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
struct fbcon_ops *ops = info->fbcon_par;
struct fbcon_display *p = &fb_display[vc->vc_num];
int resize;
int cnt;
char *old_data = NULL;

resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
if (p->userfont)
old_data = vc->vc_font.data;
if (userfont)
cnt = FNTCHARCNT(data);
else
cnt = 256;
vc->vc_font.data = (void *)(p->fontdata = data);
if ((p->userfont = userfont))
REFCOUNT(data)++;
vc->vc_font.width = w;
vc->vc_font.height = h;
if (vc->vc_hi_font_mask && cnt == 256)
vc->vc_font.charcount = charcount;
if (vc->vc_hi_font_mask && charcount == 256)
set_vc_hi_font(vc, false);
else if (!vc->vc_hi_font_mask && cnt == 512)
else if (!vc->vc_hi_font_mask && charcount == 512)
set_vc_hi_font(vc, true);

if (resize) {
Expand Down Expand Up @@ -2496,9 +2485,10 @@ static int fbcon_set_font(struct vc_data *vc, struct console_font *font,
if (!new_data)
return -ENOMEM;

memset(new_data, 0, FONT_EXTRA_WORDS * sizeof(int));

new_data += FONT_EXTRA_WORDS * sizeof(int);
FNTSIZE(new_data) = size;
FNTCHARCNT(new_data) = charcount;
REFCOUNT(new_data) = 0; /* usage counter */
for (i=0; i< charcount; i++) {
memcpy(new_data + i*h*pitch, data + i*32*pitch, h*pitch);
Expand All @@ -2524,7 +2514,7 @@ static int fbcon_set_font(struct vc_data *vc, struct console_font *font,
break;
}
}
return fbcon_do_set_font(vc, font->width, font->height, new_data, 1);
return fbcon_do_set_font(vc, font->width, font->height, charcount, new_data, 1);
}

static int fbcon_set_def_font(struct vc_data *vc, struct console_font *font, char *name)
Expand All @@ -2540,7 +2530,7 @@ static int fbcon_set_def_font(struct vc_data *vc, struct console_font *font, cha

font->width = f->width;
font->height = f->height;
return fbcon_do_set_font(vc, f->width, f->height, f->data, 0);
return fbcon_do_set_font(vc, f->width, f->height, f->charcount, f->data, 0);
}

static u16 palette_red[16];
Expand Down Expand Up @@ -3009,7 +2999,6 @@ void fbcon_get_requirement(struct fb_info *info,
struct fb_blit_caps *caps)
{
struct vc_data *vc;
struct fbcon_display *p;

if (caps->flags) {
int i, charcnt;
Expand All @@ -3018,11 +3007,9 @@ void fbcon_get_requirement(struct fb_info *info,
vc = vc_cons[i].d;
if (vc && vc->vc_mode == KD_TEXT &&
info->node == con2fb_map[i]) {
p = &fb_display[i];
caps->x |= 1 << (vc->vc_font.width - 1);
caps->y |= 1 << (vc->vc_font.height - 1);
charcnt = (p->userfont) ?
FNTCHARCNT(p->fontdata) : 256;
charcnt = vc->vc_font.charcount;
if (caps->len < charcnt)
caps->len = charcnt;
}
Expand All @@ -3032,11 +3019,9 @@ void fbcon_get_requirement(struct fb_info *info,

if (vc && vc->vc_mode == KD_TEXT &&
info->node == con2fb_map[fg_console]) {
p = &fb_display[fg_console];
caps->x = 1 << (vc->vc_font.width - 1);
caps->y = 1 << (vc->vc_font.height - 1);
caps->len = (p->userfont) ?
FNTCHARCNT(p->fontdata) : 256;
caps->len = vc->vc_font.charcount;
}
}
}
Expand Down
3 changes: 1 addition & 2 deletions drivers/video/fbdev/core/fbcon_rotate.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,6 @@
#include <linux/fb.h>
#include <linux/vt_kern.h>
#include <linux/console.h>
#include <linux/font.h>
#include <asm/types.h>
#include "fbcon.h"
#include "fbcon_rotate.h"
Expand All @@ -33,7 +32,7 @@ static int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc)

src = ops->fontdata = vc->vc_font.data;
ops->cur_rotate = ops->p->con_rotate;
len = (!ops->p->userfont) ? 256 : FNTCHARCNT(src);
len = vc->vc_font.charcount;
s_cellsize = ((vc->vc_font.width + 7)/8) *
vc->vc_font.height;
d_cellsize = s_cellsize;
Expand Down
4 changes: 1 addition & 3 deletions drivers/video/fbdev/core/tileblit.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,6 @@
#include <linux/fb.h>
#include <linux/vt_kern.h>
#include <linux/console.h>
#include <linux/font.h>
#include <asm/types.h>
#include "fbcon.h"

Expand Down Expand Up @@ -145,8 +144,7 @@ void fbcon_set_tileops(struct vc_data *vc, struct fb_info *info)
map.width = vc->vc_font.width;
map.height = vc->vc_font.height;
map.depth = 1;
map.length = (ops->p->userfont) ?
FNTCHARCNT(ops->p->fontdata) : 256;
map.length = vc->vc_font.charcount;
map.data = ops->p->fontdata;
info->tileops->fb_settile(info, &map);
}
Expand Down

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