linux/drivers/video/console/dummycon.c
Kees Cook c396a5bf45 console: Expand dummy functions for CFI
This expands the no-op dummy functions into full prototypes to avoid
indirect call mismatches when running under Control Flow Integrity
checking, like with Clang's -fsanitize=cfi.

Co-Developed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-27 10:17:33 +01:00

109 lines
2.6 KiB
C

/*
* linux/drivers/video/dummycon.c -- A dummy console driver
*
* To be used if there's no other console driver (e.g. for plain VGA text)
* available, usually until fbcon takes console over.
*/
#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/console.h>
#include <linux/vt_kern.h>
#include <linux/screen_info.h>
#include <linux/init.h>
#include <linux/module.h>
/*
* Dummy console driver
*/
#if defined(__arm__)
#define DUMMY_COLUMNS screen_info.orig_video_cols
#define DUMMY_ROWS screen_info.orig_video_lines
#else
/* set by Kconfig. Use 80x25 for 640x480 and 160x64 for 1280x1024 */
#define DUMMY_COLUMNS CONFIG_DUMMY_CONSOLE_COLUMNS
#define DUMMY_ROWS CONFIG_DUMMY_CONSOLE_ROWS
#endif
static const char *dummycon_startup(void)
{
return "dummy device";
}
static void dummycon_init(struct vc_data *vc, int init)
{
vc->vc_can_do_color = 1;
if (init) {
vc->vc_cols = DUMMY_COLUMNS;
vc->vc_rows = DUMMY_ROWS;
} else
vc_resize(vc, DUMMY_COLUMNS, DUMMY_ROWS);
}
static void dummycon_deinit(struct vc_data *vc) { }
static void dummycon_clear(struct vc_data *vc, int sy, int sx, int height,
int width) { }
static void dummycon_putc(struct vc_data *vc, int c, int ypos, int xpos) { }
static void dummycon_putcs(struct vc_data *vc, const unsigned short *s,
int count, int ypos, int xpos) { }
static void dummycon_cursor(struct vc_data *vc, int mode) { }
static bool dummycon_scroll(struct vc_data *vc, unsigned int top,
unsigned int bottom, enum con_scroll dir,
unsigned int lines)
{
return false;
}
static int dummycon_switch(struct vc_data *vc)
{
return 0;
}
static int dummycon_blank(struct vc_data *vc, int blank, int mode_switch)
{
return 0;
}
static int dummycon_font_set(struct vc_data *vc, struct console_font *font,
unsigned int flags)
{
return 0;
}
static int dummycon_font_default(struct vc_data *vc,
struct console_font *font, char *name)
{
return 0;
}
static int dummycon_font_copy(struct vc_data *vc, int con)
{
return 0;
}
/*
* The console `switch' structure for the dummy console
*
* Most of the operations are dummies.
*/
const struct consw dummy_con = {
.owner = THIS_MODULE,
.con_startup = dummycon_startup,
.con_init = dummycon_init,
.con_deinit = dummycon_deinit,
.con_clear = dummycon_clear,
.con_putc = dummycon_putc,
.con_putcs = dummycon_putcs,
.con_cursor = dummycon_cursor,
.con_scroll = dummycon_scroll,
.con_switch = dummycon_switch,
.con_blank = dummycon_blank,
.con_font_set = dummycon_font_set,
.con_font_default = dummycon_font_default,
.con_font_copy = dummycon_font_copy,
};
EXPORT_SYMBOL_GPL(dummy_con);