linux-next/include/linux/fbcon.h
Helge Deller e64242caef fbcon: Prevent that screen size is smaller than font size
We need to prevent that users configure a screen size which is smaller than the
currently selected font size. Otherwise rendering chars on the screen will
access memory outside the graphics memory region.

This patch adds a new function fbcon_modechange_possible() which
implements this check and which later may be extended with other checks
if necessary.  The new function is called from the FBIOPUT_VSCREENINFO
ioctl handler in fbmem.c, which will return -EINVAL if userspace asked
for a too small screen size.

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # v5.4+
2022-07-07 10:50:46 +02:00

47 lines
2.1 KiB
C

#ifndef _LINUX_FBCON_H
#define _LINUX_FBCON_H
#ifdef CONFIG_FRAMEBUFFER_CONSOLE
void __init fb_console_init(void);
void __exit fb_console_exit(void);
int fbcon_fb_registered(struct fb_info *info);
void fbcon_fb_unregistered(struct fb_info *info);
void fbcon_fb_unbind(struct fb_info *info);
void fbcon_suspended(struct fb_info *info);
void fbcon_resumed(struct fb_info *info);
int fbcon_mode_deleted(struct fb_info *info,
struct fb_videomode *mode);
void fbcon_new_modelist(struct fb_info *info);
void fbcon_get_requirement(struct fb_info *info,
struct fb_blit_caps *caps);
void fbcon_fb_blanked(struct fb_info *info, int blank);
int fbcon_modechange_possible(struct fb_info *info,
struct fb_var_screeninfo *var);
void fbcon_update_vcs(struct fb_info *info, bool all);
void fbcon_remap_all(struct fb_info *info);
int fbcon_set_con2fb_map_ioctl(void __user *argp);
int fbcon_get_con2fb_map_ioctl(void __user *argp);
#else
static inline void fb_console_init(void) {}
static inline void fb_console_exit(void) {}
static inline int fbcon_fb_registered(struct fb_info *info) { return 0; }
static inline void fbcon_fb_unregistered(struct fb_info *info) {}
static inline void fbcon_fb_unbind(struct fb_info *info) {}
static inline void fbcon_suspended(struct fb_info *info) {}
static inline void fbcon_resumed(struct fb_info *info) {}
static inline int fbcon_mode_deleted(struct fb_info *info,
struct fb_videomode *mode) { return 0; }
static inline void fbcon_new_modelist(struct fb_info *info) {}
static inline void fbcon_get_requirement(struct fb_info *info,
struct fb_blit_caps *caps) {}
static inline void fbcon_fb_blanked(struct fb_info *info, int blank) {}
static inline int fbcon_modechange_possible(struct fb_info *info,
struct fb_var_screeninfo *var) { return 0; }
static inline void fbcon_update_vcs(struct fb_info *info, bool all) {}
static inline void fbcon_remap_all(struct fb_info *info) {}
static inline int fbcon_set_con2fb_map_ioctl(void __user *argp) { return 0; }
static inline int fbcon_get_con2fb_map_ioctl(void __user *argp) { return 0; }
#endif
#endif /* _LINUX_FBCON_H */