// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/*
 * Hopefully this will be a rather complete VT102 implementation.
 *
 * Beeping thanks to John T Kohl.
 *
 * Virtual Consoles, Screen Blanking, Screen Dumping, Color, Graphics
 *   Chars, and VT100 enhancements by Peter MacDonald.
 *
 * Copy and paste function by Andrew Haylett,
 *   some enhancements by Alessandro Rubini.
 *
 * Code to check for different video-cards mostly by Galen Hunt,
 * <g-hunt@ee.utah.edu>
 *
 * Rudimentary ISO 10646/Unicode/UTF-8 character set support by
 * Markus Kuhn, <mskuhn@immd4.informatik.uni-erlangen.de>.
 *
 * Dynamic allocation of consoles, aeb@cwi.nl, May 1994
 * Resizing of consoles, aeb, 940926
 *
 * Code for xterm like mouse click reporting by Peter Orbaek 20-Jul-94
 * <poe@daimi.aau.dk>
 *
 * User-defined bell sound, new setterm control sequences and printk
 * redirection by Martin Mares <mj@k332.feld.cvut.cz> 19-Nov-95
 *
 * APM screenblank bug fixed Takashi Manabe <manabe@roy.dsl.tutics.tut.jp>
 *
 * Merge with the abstract console driver by Geert Uytterhoeven
 * <geert@linux-m68k.org>, Jan 1997.
 *
 *   Original m68k console driver modifications by
 *
 *     - Arno Griffioen <arno@usn.nl>
 *     - David Carter <carter@cs.bris.ac.uk>
 * 
 *   The abstract console driver provides a generic interface for a text
 *   console. It supports VGA text mode, frame buffer based graphical consoles
 *   and special graphics processors that are only accessible through some
 *   registers (e.g. a TMS340x0 GSP).
 *
 *   The interface to the hardware is specified using a special structure
 *   (struct consw) which contains function pointers to console operations
 *   (see <linux/console.h> for more information).
 *
 * Support for changeable cursor shape
 * by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>, August 1997
 *
 * Ported to i386 and con_scrolldelta fixed
 * by Emmanuel Marty <core@ggi-project.org>, April 1998
 *
 * Resurrected character buffers in videoram plus lots of other trickery
 * by Martin Mares <mj@atrey.karlin.mff.cuni.cz>, July 1998
 *
 * Removed old-style timers, introduced console_timer, made timer
 * deletion SMP-safe.  17Jun00, Andrew Morton
 *
 * Removed console_lock, enabled interrupts across all console operations
 * 13 March 2001, Andrew Morton
 *
 * Fixed UTF-8 mode so alternate charset modes always work according
 * to control sequences interpreted in do_con_trol function
 * preserving backward VT100 semigraphics compatibility,
 * malformed UTF sequences represented as sequences of replacement glyphs,
 * original codes or '?' as a last resort if replacement glyph is undefined
 * by Adam Tla/lka <atlka@pg.gda.pl>, Aug 2006
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched/signal.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/kd.h>
#include <linux/slab.h>
#include <linux/major.h>
#include <linux/mm.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/vt_kern.h>
#include <linux/selection.h>
#include <linux/tiocl.h>
#include <linux/kbd_kern.h>
#include <linux/consolemap.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/pm.h>
#include <linux/font.h>
#include <linux/bitops.h>
#include <linux/notifier.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/kdb.h>
#include <linux/ctype.h>
#include <linux/bsearch.h>
#include <linux/gcd.h>

#define MAX_NR_CON_DRIVER 16

#define CON_DRIVER_FLAG_MODULE 1
#define CON_DRIVER_FLAG_INIT   2
#define CON_DRIVER_FLAG_ATTR   4
#define CON_DRIVER_FLAG_ZOMBIE 8

struct con_driver {
        const struct consw *con;
        const char *desc;
        struct device *dev;
        int node;
        int first;
        int last;
        int flag;
};

static struct con_driver registered_con_driver[MAX_NR_CON_DRIVER];
const struct consw *conswitchp;

/* A bitmap for codes <32. A bit of 1 indicates that the code
 * corresponding to that bit number invokes some special action
 * (such as cursor movement) and should not be displayed as a
 * glyph unless the disp_ctrl mode is explicitly enabled.
 */
#define CTRL_ACTION 0x0d00ff81
#define CTRL_ALWAYS 0x0800f501  /* Cannot be overridden by disp_ctrl */

/*
 * Here is the default bell parameters: 750HZ, 1/8th of a second
 */
#define DEFAULT_BELL_PITCH      750
#define DEFAULT_BELL_DURATION   (HZ/8)
#define DEFAULT_CURSOR_BLINK_MS 200

struct vc vc_cons [MAX_NR_CONSOLES];

#ifndef VT_SINGLE_DRIVER
static const struct consw *con_driver_map[MAX_NR_CONSOLES];
#endif

static int con_open(struct tty_struct *, struct file *);
static void vc_init(struct vc_data *vc, unsigned int rows,
                    unsigned int cols, int do_clear);
static void gotoxy(struct vc_data *vc, int new_x, int new_y);
static void save_cur(struct vc_data *vc);
static void reset_terminal(struct vc_data *vc, int do_clear);
static void con_flush_chars(struct tty_struct *tty);
static int set_vesa_blanking(char __user *p);
static void set_cursor(struct vc_data *vc);
static void hide_cursor(struct vc_data *vc);
static void console_callback(struct work_struct *ignored);
static void con_driver_unregister_callback(struct work_struct *ignored);
static void blank_screen_t(struct timer_list *unused);
static void set_palette(struct vc_data *vc);

#define vt_get_kmsg_redirect() vt_kmsg_redirect(-1)

static int printable;           /* Is console ready for printing? */
int default_utf8 = true;
module_param(default_utf8, int, S_IRUGO | S_IWUSR);
int global_cursor_default = -1;
module_param(global_cursor_default, int, S_IRUGO | S_IWUSR);

static int cur_default = CUR_DEFAULT;
module_param(cur_default, int, S_IRUGO | S_IWUSR);

/*
 * ignore_poke: don't unblank the screen when things are typed.  This is
 * mainly for the privacy of braille terminal users.
 */
static int ignore_poke;

int do_poke_blanked_console;
int console_blanked;

static int vesa_blank_mode; /* 0:none 1:suspendV 2:suspendH 3:powerdown */
static int vesa_off_interval;
static int blankinterval;
core_param(consoleblank, blankinterval, int, 0444);

static DECLARE_WORK(console_work, console_callback);
static DECLARE_WORK(con_driver_unregister_work, con_driver_unregister_callback);

/*
 * fg_console is the current virtual console,
 * last_console is the last used one,
 * want_console is the console we want to switch to,
 * saved_* variants are for save/restore around kernel debugger enter/leave
 */
int fg_console;
int last_console;
int want_console = -1;
static int saved_fg_console;
static int saved_last_console;
static int saved_want_console;
static int saved_vc_mode;
static int saved_console_blanked;

/*
 * For each existing display, we have a pointer to console currently visible
 * on that display, allowing consoles other than fg_console to be refreshed
 * appropriately. Unless the low-level driver supplies its own display_fg
 * variable, we use this one for the "master display".
 */
static struct vc_data *master_display_fg;

/*
 * Unfortunately, we need to delay tty echo when we're currently writing to the
 * console since the code is (and always was) not re-entrant, so we schedule
 * all flip requests to process context with schedule-task() and run it from
 * console_callback().
 */

/*
 * For the same reason, we defer scrollback to the console callback.
 */
static int scrollback_delta;

/*
 * Hook so that the power management routines can (un)blank
 * the console on our behalf.
 */
int (*console_blank_hook)(int);

static DEFINE_TIMER(console_timer, blank_screen_t);
static int blank_state;
static int blank_timer_expired;
enum {
        blank_off = 0,
        blank_normal_wait,
        blank_vesa_wait,
};

/*
 * /sys/class/tty/tty0/
 *
 * the attribute 'active' contains the name of the current vc
 * console and it supports poll() to detect vc switches
 */
static struct device *tty0dev;

/*
 * Notifier list for console events.
 */
static ATOMIC_NOTIFIER_HEAD(vt_notifier_list);

int register_vt_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_register(&vt_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(register_vt_notifier);

int unregister_vt_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_unregister(&vt_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(unregister_vt_notifier);

static void notify_write(struct vc_data *vc, unsigned int unicode)
{
        struct vt_notifier_param param = { .vc = vc, .c = unicode };
        atomic_notifier_call_chain(&vt_notifier_list, VT_WRITE, &param);
}

static void notify_update(struct vc_data *vc)
{
        struct vt_notifier_param param = { .vc = vc };
        atomic_notifier_call_chain(&vt_notifier_list, VT_UPDATE, &param);
}
/*
 *      Low-Level Functions
 */

static inline bool con_is_fg(const struct vc_data *vc)
{
        return vc->vc_num == fg_console;
}

static inline bool con_should_update(const struct vc_data *vc)
{
        return con_is_visible(vc) && !console_blanked;
}

static inline unsigned short *screenpos(struct vc_data *vc, int offset, int viewed)
{
        unsigned short *p;
        
        if (!viewed)
                p = (unsigned short *)(vc->vc_origin + offset);
        else if (!vc->vc_sw->con_screen_pos)
                p = (unsigned short *)(vc->vc_visible_origin + offset);
        else
                p = vc->vc_sw->con_screen_pos(vc, offset);
        return p;
}

/* Called  from the keyboard irq path.. */
static inline void scrolldelta(int lines)
{
        /* FIXME */
        /* scrolldelta needs some kind of consistency lock, but the BKL was
           and still is not protecting versus the scheduled back end */
        scrollback_delta += lines;
        schedule_console_callback();
}

void schedule_console_callback(void)
{
        schedule_work(&console_work);
}

/*
 * Code to manage unicode-based screen buffers
 */

#ifdef NO_VC_UNI_SCREEN
/* this disables and optimizes related code away at compile time */
#define get_vc_uniscr(vc) NULL
#else
#define get_vc_uniscr(vc) vc->vc_uni_screen
#endif

#define VC_UNI_SCREEN_DEBUG 0

typedef uint32_t char32_t;

/*
 * Our screen buffer is preceded by an array of line pointers so that
 * scrolling only implies some pointer shuffling.
 */
struct uni_screen {
        char32_t *lines[0];
};

static struct uni_screen *vc_uniscr_alloc(unsigned int cols, unsigned int rows)
{
        struct uni_screen *uniscr;
        void *p;
        unsigned int memsize, i;

        /* allocate everything in one go */
        memsize = cols * rows * sizeof(char32_t);
        memsize += rows * sizeof(char32_t *);
        p = kmalloc(memsize, GFP_KERNEL);
        if (!p)
                return NULL;

        /* initial line pointers */
        uniscr = p;
        p = uniscr->lines + rows;
        for (i = 0; i < rows; i++) {
                uniscr->lines[i] = p;
                p += cols * sizeof(char32_t);
        }
        return uniscr;
}

static void vc_uniscr_set(struct vc_data *vc, struct uni_screen *new_uniscr)
{
        kfree(vc->vc_uni_screen);
        vc->vc_uni_screen = new_uniscr;
}

static void vc_uniscr_putc(struct vc_data *vc, char32_t uc)
{
        struct uni_screen *uniscr = get_vc_uniscr(vc);

        if (uniscr)
                uniscr->lines[vc->vc_y][vc->vc_x] = uc;
}

static void vc_uniscr_insert(struct vc_data *vc, unsigned int nr)
{
        struct uni_screen *uniscr = get_vc_uniscr(vc);

        if (uniscr) {
                char32_t *ln = uniscr->lines[vc->vc_y];
                unsigned int x = vc->vc_x, cols = vc->vc_cols;

                memmove(&ln[x + nr], &ln[x], (cols - x - nr) * sizeof(*ln));
                memset32(&ln[x], ' ', nr);
        }
}

static void vc_uniscr_delete(struct vc_data *vc, unsigned int nr)
{
        struct uni_screen *uniscr = get_vc_uniscr(vc);

        if (uniscr) {
                char32_t *ln = uniscr->lines[vc->vc_y];
                unsigned int x = vc->vc_x, cols = vc->vc_cols;

                memcpy(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
                memset32(&ln[cols - nr], ' ', nr);
        }
}

static void vc_uniscr_clear_line(struct vc_data *vc, unsigned int x,
                                 unsigned int nr)
{
        struct uni_screen *uniscr = get_vc_uniscr(vc);

        if (uniscr) {
                char32_t *ln = uniscr->lines[vc->vc_y];

                memset32(&ln[x], ' ', nr);
        }
}

static void vc_uniscr_clear_lines(struct vc_data *vc, unsigned int y,
                                  unsigned int nr)
{
        struct uni_screen *uniscr = get_vc_uniscr(vc);

        if (uniscr) {
                unsigned int cols = vc->vc_cols;

                while (nr--)
                        memset32(uniscr->lines[y++], ' ', cols);
        }
}

static void vc_uniscr_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
                             enum con_scroll dir, unsigned int nr)
{
        struct uni_screen *uniscr = get_vc_uniscr(vc);

        if (uniscr) {
                unsigned int i, j, k, sz, d, clear;

                sz = b - t;
                clear = b - nr;
                d = nr;
                if (dir == SM_DOWN) {
                        clear = t;
                        d = sz - nr;
                }
                for (i = 0; i < gcd(d, sz); i++) {
                        char32_t *tmp = uniscr->lines[t + i];
                        j = i;
                        while (1) {
                                k = j + d;
                                if (k >= sz)
                                        k -= sz;
                                if (k == i)
                                        break;
                                uniscr->lines[t + j] = uniscr->lines[t + k];
                                j = k;
                        }
                        uniscr->lines[t + j] = tmp;
                }
                vc_uniscr_clear_lines(vc, clear, nr);
        }
}

static void vc_uniscr_copy_area(struct uni_screen *dst,
                                unsigned int dst_cols,
                                unsigned int dst_rows,
                                struct uni_screen *src,
                                unsigned int src_cols,
                                unsigned int src_top_row,
                                unsigned int src_bot_row)
{
        unsigned int dst_row = 0;

        if (!dst)
                return;

        while (src_top_row < src_bot_row) {
                char32_t *src_line = src->lines[src_top_row];
                char32_t *dst_line = dst->lines[dst_row];

                memcpy(dst_line, src_line, src_cols * sizeof(char32_t));
                if (dst_cols - src_cols)
                        memset32(dst_line + src_cols, ' ', dst_cols - src_cols);
                src_top_row++;
                dst_row++;
        }
        while (dst_row < dst_rows) {
                char32_t *dst_line = dst->lines[dst_row];

                memset32(dst_line, ' ', dst_cols);
                dst_row++;
        }
}

/*
 * Called from vcs_read() to make sure unicode screen retrieval is possible.
 * This will initialize the unicode screen buffer if not already done.
 * This returns 0 if OK, or a negative error code otherwise.
 * In particular, -ENODATA is returned if the console is not in UTF-8 mode.
 */
int vc_uniscr_check(struct vc_data *vc)
{
        struct uni_screen *uniscr;
        unsigned short *p;
        int x, y, mask;

        if (__is_defined(NO_VC_UNI_SCREEN))
                return -EOPNOTSUPP;

        WARN_CONSOLE_UNLOCKED();

        if (!vc->vc_utf)
                return -ENODATA;

        if (vc->vc_uni_screen)
                return 0;

        uniscr = vc_uniscr_alloc(vc->vc_cols, vc->vc_rows);
        if (!uniscr)
                return -ENOMEM;

        /*
         * Let's populate it initially with (imperfect) reverse translation.
         * This is the next best thing we can do short of having it enabled
         * from the start even when no users rely on this functionality. True
         * unicode content will be available after a complete screen refresh.
         */
        p = (unsigned short *)vc->vc_origin;
        mask = vc->vc_hi_font_mask | 0xff;
        for (y = 0; y < vc->vc_rows; y++) {
                char32_t *line = uniscr->lines[y];
                for (x = 0; x < vc->vc_cols; x++) {
                        u16 glyph = scr_readw(p++) & mask;
                        line[x] = inverse_translate(vc, glyph, true);
                }
        }

        vc->vc_uni_screen = uniscr;
        return 0;
}

/*
 * Called from vcs_read() to get the unicode data from the screen.
 * This must be preceded by a successful call to vc_uniscr_check() once
 * the console lock has been taken.
 */
void vc_uniscr_copy_line(struct vc_data *vc, void *dest, int viewed,
                         unsigned int row, unsigned int col, unsigned int nr)
{
        struct uni_screen *uniscr = get_vc_uniscr(vc);
        int offset = row * vc->vc_size_row + col * 2;
        unsigned long pos;

        BUG_ON(!uniscr);

        pos = (unsigned long)screenpos(vc, offset, viewed);
        if (pos >= vc->vc_origin && pos < vc->vc_scr_end) {
                /*
                 * Desired position falls in the main screen buffer.
                 * However the actual row/col might be different if
                 * scrollback is active.
                 */
                row = (pos - vc->vc_origin) / vc->vc_size_row;
                col = ((pos - vc->vc_origin) % vc->vc_size_row) / 2;
                memcpy(dest, &uniscr->lines[row][col], nr * sizeof(char32_t));
        } else {
                /*
                 * Scrollback is active. For now let's simply backtranslate
                 * the screen glyphs until the unicode screen buffer does
                 * synchronize with console display drivers for a scrollback
                 * buffer of its own.
                 */
                u16 *p = (u16 *)pos;
                int mask = vc->vc_hi_font_mask | 0xff;
                char32_t *uni_buf = dest;
                while (nr--) {
                        u16 glyph = scr_readw(p++) & mask;
                        *uni_buf++ = inverse_translate(vc, glyph, true);
                }
        }
}

/* this is for validation and debugging only */
static void vc_uniscr_debug_check(struct vc_data *vc)
{
        struct uni_screen *uniscr = get_vc_uniscr(vc);
        unsigned short *p;
        int x, y, mask;

        if (!VC_UNI_SCREEN_DEBUG || !uniscr)
                return;

        WARN_CONSOLE_UNLOCKED();

        /*
         * Make sure our unicode screen translates into the same glyphs
         * as the actual screen. This is brutal indeed.
         */
        p = (unsigned short *)vc->vc_origin;
        mask = vc->vc_hi_font_mask | 0xff;
        for (y = 0; y < vc->vc_rows; y++) {
                char32_t *line = uniscr->lines[y];
                for (x = 0; x < vc->vc_cols; x++) {
                        u16 glyph = scr_readw(p++) & mask;
                        char32_t uc = line[x];
                        int tc = conv_uni_to_pc(vc, uc);
                        if (tc == -4)
                                tc = conv_uni_to_pc(vc, 0xfffd);
                        if (tc == -4)
                                tc = conv_uni_to_pc(vc, '?');
                        if (tc != glyph)
                                pr_err_ratelimited(
                                        "%s: mismatch at %d,%d: glyph=%#x tc=%#x\n",
                                        __func__, x, y, glyph, tc);
                }
        }
}


static void con_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
                enum con_scroll dir, unsigned int nr)
{
        u16 *clear, *d, *s;

        if (t + nr >= b)
                nr = b - t - 1;
        if (b > vc->vc_rows || t >= b || nr < 1)
                return;
        vc_uniscr_scroll(vc, t, b, dir, nr);
        if (con_is_visible(vc) && vc->vc_sw->con_scroll(vc, t, b, dir, nr))
                return;

        s = clear = (u16 *)(vc->vc_origin + vc->vc_size_row * t);
        d = (u16 *)(vc->vc_origin + vc->vc_size_row * (t + nr));

        if (dir == SM_UP) {
                clear = s + (b - t - nr) * vc->vc_cols;
                swap(s, d);
        }
        scr_memmovew(d, s, (b - t - nr) * vc->vc_size_row);
        scr_memsetw(clear, vc->vc_video_erase_char, vc->vc_size_row * nr);
}

static void do_update_region(struct vc_data *vc, unsigned long start, int count)
{
        unsigned int xx, yy, offset;
        u16 *p;

        p = (u16 *) start;
        if (!vc->vc_sw->con_getxy) {
                offset = (start - vc->vc_origin) / 2;
                xx = offset % vc->vc_cols;
                yy = offset / vc->vc_cols;
        } else {
                int nxx, nyy;
                start = vc->vc_sw->con_getxy(vc, start, &nxx, &nyy);
                xx = nxx; yy = nyy;
        }
        for(;;) {
                u16 attrib = scr_readw(p) & 0xff00;
                int startx = xx;
                u16 *q = p;
                while (xx < vc->vc_cols && count) {
                        if (attrib != (scr_readw(p) & 0xff00)) {
                                if (p > q)
                                        vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
                                startx = xx;
                                q = p;
                                attrib = scr_readw(p) & 0xff00;
                        }
                        p++;
                        xx++;
                        count--;
                }
                if (p > q)
                        vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
                if (!count)
                        break;
                xx = 0;
                yy++;
                if (vc->vc_sw->con_getxy) {
                        p = (u16 *)start;
                        start = vc->vc_sw->con_getxy(vc, start, NULL, NULL);
                }
        }
}

void update_region(struct vc_data *vc, unsigned long start, int count)
{
        WARN_CONSOLE_UNLOCKED();

        if (con_should_update(vc)) {
                hide_cursor(vc);
                do_update_region(vc, start, count);
                set_cursor(vc);
        }
}

/* Structure of attributes is hardware-dependent */

static u8 build_attr(struct vc_data *vc, u8 _color, u8 _intensity, u8 _blink,
    u8 _underline, u8 _reverse, u8 _italic)
{
        if (vc->vc_sw->con_build_attr)
                return vc->vc_sw->con_build_attr(vc, _color, _intensity,
                       _blink, _underline, _reverse, _italic);

/*
 * ++roman: I completely changed the attribute format for monochrome
 * mode (!can_do_color). The formerly used MDA (monochrome display
 * adapter) format didn't allow the combination of certain effects.
 * Now the attribute is just a bit vector:
 *  Bit 0..1: intensity (0..2)
 *  Bit 2   : underline
 *  Bit 3   : reverse
 *  Bit 7   : blink
 */
        {
        u8 a = _color;
        if (!vc->vc_can_do_color)
                return _intensity |
                       (_italic ? 2 : 0) |
                       (_underline ? 4 : 0) |
                       (_reverse ? 8 : 0) |
                       (_blink ? 0x80 : 0);
        if (_italic)
                a = (a & 0xF0) | vc->vc_itcolor;
        else if (_underline)
                a = (a & 0xf0) | vc->vc_ulcolor;
        else if (_intensity == 0)
                a = (a & 0xf0) | vc->vc_halfcolor;
        if (_reverse)
                a = ((a) & 0x88) | ((((a) >> 4) | ((a) << 4)) & 0x77);
        if (_blink)
                a ^= 0x80;
        if (_intensity == 2)
                a ^= 0x08;
        if (vc->vc_hi_font_mask == 0x100)
                a <<= 1;
        return a;
        }
}

static void update_attr(struct vc_data *vc)
{
        vc->vc_attr = build_attr(vc, vc->vc_color, vc->vc_intensity,
                      vc->vc_blink, vc->vc_underline,
                      vc->vc_reverse ^ vc->vc_decscnm, vc->vc_italic);
        vc->vc_video_erase_char = (build_attr(vc, vc->vc_color, 1, vc->vc_blink, 0, vc->vc_decscnm, 0) << 8) | ' ';
}

/* Note: inverting the screen twice should revert to the original state */
void invert_screen(struct vc_data *vc, int offset, int count, int viewed)
{
        unsigned short *p;

        WARN_CONSOLE_UNLOCKED();

        count /= 2;
        p = screenpos(vc, offset, viewed);
        if (vc->vc_sw->con_invert_region) {
                vc->vc_sw->con_invert_region(vc, p, count);
        } else {
                u16 *q = p;
                int cnt = count;
                u16 a;

                if (!vc->vc_can_do_color) {
                        while (cnt--) {
                            a = scr_readw(q);
                            a ^= 0x0800;
                            scr_writew(a, q);
                            q++;
                        }
                } else if (vc->vc_hi_font_mask == 0x100) {
                        while (cnt--) {
                                a = scr_readw(q);
                                a = ((a) & 0x11ff) | (((a) & 0xe000) >> 4) | (((a) & 0x0e00) << 4);
                                scr_writew(a, q);
                                q++;
                        }
                } else {
                        while (cnt--) {
                                a = scr_readw(q);
                                a = ((a) & 0x88ff) | (((a) & 0x7000) >> 4) | (((a) & 0x0700) << 4);
                                scr_writew(a, q);
                                q++;
                        }
                }
        }

        if (con_should_update(vc))
                do_update_region(vc, (unsigned long) p, count);
        notify_update(vc);
}

/* used by selection: complement pointer position */
void complement_pos(struct vc_data *vc, int offset)
{
        static int old_offset = -1;
        static unsigned short old;
        static unsigned short oldx, oldy;

        WARN_CONSOLE_UNLOCKED();

        if (old_offset != -1 && old_offset >= 0 &&
            old_offset < vc->vc_screenbuf_size) {
                scr_writew(old, screenpos(vc, old_offset, 1));
                if (con_should_update(vc))
                        vc->vc_sw->con_putc(vc, old, oldy, oldx);
                notify_update(vc);
        }

        old_offset = offset;

        if (offset != -1 && offset >= 0 &&
            offset < vc->vc_screenbuf_size) {
                unsigned short new;
                unsigned short *p;
                p = screenpos(vc, offset, 1);
                old = scr_readw(p);
                new = old ^ vc->vc_complement_mask;
                scr_writew(new, p);
                if (con_should_update(vc)) {
                        oldx = (offset >> 1) % vc->vc_cols;
                        oldy = (offset >> 1) / vc->vc_cols;
                        vc->vc_sw->con_putc(vc, new, oldy, oldx);
                }
                notify_update(vc);
        }
}

static void insert_char(struct vc_data *vc, unsigned int nr)
{
        unsigned short *p = (unsigned short *) vc->vc_pos;

        vc_uniscr_insert(vc, nr);
        scr_memmovew(p + nr, p, (vc->vc_cols - vc->vc_x - nr) * 2);
        scr_memsetw(p, vc->vc_video_erase_char, nr * 2);
        vc->vc_need_wrap = 0;
        if (con_should_update(vc))
                do_update_region(vc, (unsigned long) p,
                        vc->vc_cols - vc->vc_x);
}

static void delete_char(struct vc_data *vc, unsigned int nr)
{
        unsigned short *p = (unsigned short *) vc->vc_pos;

        vc_uniscr_delete(vc, nr);
        scr_memcpyw(p, p + nr, (vc->vc_cols - vc->vc_x - nr) * 2);
        scr_memsetw(p + vc->vc_cols - vc->vc_x - nr, vc->vc_video_erase_char,
                        nr * 2);
        vc->vc_need_wrap = 0;
        if (con_should_update(vc))
                do_update_region(vc, (unsigned long) p,
                        vc->vc_cols - vc->vc_x);
}

static int softcursor_original = -1;

static void add_softcursor(struct vc_data *vc)
{
        int i = scr_readw((u16 *) vc->vc_pos);
        u32 type = vc->vc_cursor_type;

        if (! (type & 0x10)) return;
        if (softcursor_original != -1) return;
        softcursor_original = i;
        i |= ((type >> 8) & 0xff00 );
        i ^= ((type) & 0xff00 );
        if ((type & 0x20) && ((softcursor_original & 0x7000) == (i & 0x7000))) i ^= 0x7000;
        if ((type & 0x40) && ((i & 0x700) == ((i & 0x7000) >> 4))) i ^= 0x0700;
        scr_writew(i, (u16 *) vc->vc_pos);
        if (con_should_update(vc))
                vc->vc_sw->con_putc(vc, i, vc->vc_y, vc->vc_x);
}

static void hide_softcursor(struct vc_data *vc)
{
        if (softcursor_original != -1) {
                scr_writew(softcursor_original, (u16 *)vc->vc_pos);
                if (con_should_update(vc))
                        vc->vc_sw->con_putc(vc, softcursor_original,
                                        vc->vc_y, vc->vc_x);
                softcursor_original = -1;
        }
}

static void hide_cursor(struct vc_data *vc)
{
        if (vc == sel_cons)
                clear_selection();
        vc->vc_sw->con_cursor(vc, CM_ERASE);
        hide_softcursor(vc);
}

static void set_cursor(struct vc_data *vc)
{
        if (!con_is_fg(vc) || console_blanked || vc->vc_mode == KD_GRAPHICS)
                return;
        if (vc->vc_deccm) {
                if (vc == sel_cons)
                        clear_selection();
                add_softcursor(vc);
                if ((vc->vc_cursor_type & 0x0f) != 1)
                        vc->vc_sw->con_cursor(vc, CM_DRAW);
        } else
                hide_cursor(vc);
}

static void set_origin(struct vc_data *vc)
{
        WARN_CONSOLE_UNLOCKED();

        if (!con_is_visible(vc) ||
            !vc->vc_sw->con_set_origin ||
            !vc->vc_sw->con_set_origin(vc))
                vc->vc_origin = (unsigned long)vc->vc_screenbuf;
        vc->vc_visible_origin = vc->vc_origin;
        vc->vc_scr_end = vc->vc_origin + vc->vc_screenbuf_size;
        vc->vc_pos = vc->vc_origin + vc->vc_size_row * vc->vc_y + 2 * vc->vc_x;
}

static void save_screen(struct vc_data *vc)
{
        WARN_CONSOLE_UNLOCKED();

        if (vc->vc_sw->con_save_screen)
                vc->vc_sw->con_save_screen(vc);
}

static void flush_scrollback(struct vc_data *vc)
{
        WARN_CONSOLE_UNLOCKED();

        if (vc->vc_sw->con_flush_scrollback)
                vc->vc_sw->con_flush_scrollback(vc);
}

/*
 *      Redrawing of screen
 */

void clear_buffer_attributes(struct vc_data *vc)
{
        unsigned short *p = (unsigned short *)vc->vc_origin;
        int count = vc->vc_screenbuf_size / 2;
        int mask = vc->vc_hi_font_mask | 0xff;

        for (; count > 0; count--, p++) {
                scr_writew((scr_readw(p)&mask) | (vc->vc_video_erase_char & ~mask), p);
        }
}

void redraw_screen(struct vc_data *vc, int is_switch)
{
        int redraw = 0;

        WARN_CONSOLE_UNLOCKED();

        if (!vc) {
                /* strange ... */
                /* printk("redraw_screen: tty %d not allocated ??\n", new_console+1); */
                return;
        }

        if (is_switch) {
                struct vc_data *old_vc = vc_cons[fg_console].d;
                if (old_vc == vc)
                        return;
                if (!con_is_visible(vc))
                        redraw = 1;
                *vc->vc_display_fg = vc;
                fg_console = vc->vc_num;
                hide_cursor(old_vc);
                if (!con_is_visible(old_vc)) {
                        save_screen(old_vc);
                        set_origin(old_vc);
                }
                if (tty0dev)
                        sysfs_notify(&tty0dev->kobj, NULL, "active");
        } else {
                hide_cursor(vc);
                redraw = 1;
        }

        if (redraw) {
                int update;
                int old_was_color = vc->vc_can_do_color;

                set_origin(vc);
                update = vc->vc_sw->con_switch(vc);
                set_palette(vc);
                /*
                 * If console changed from mono<->color, the best we can do
                 * is to clear the buffer attributes. As it currently stands,
                 * rebuilding new attributes from the old buffer is not doable
                 * without overly complex code.

                 */
                if (old_was_color != vc->vc_can_do_color) {
                        update_attr(vc);
                        clear_buffer_attributes(vc);
                }

                /* Forcibly update if we're panicing */
                if ((update && vc->vc_mode != KD_GRAPHICS) ||
                    vt_force_oops_output(vc))
                        do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
        }
        set_cursor(vc);
        if (is_switch) {
                set_leds();
                compute_shiftstate();
                notify_update(vc);
        }
}

/*
 *      Allocation, freeing and resizing of VTs.
 */

int vc_cons_allocated(unsigned int i)
{
        return (i < MAX_NR_CONSOLES && vc_cons[i].d);
}

static void visual_init(struct vc_data *vc, int num, int init)
{
        /* ++Geert: vc->vc_sw->con_init determines console size */
        if (vc->vc_sw)
                module_put(vc->vc_sw->owner);
        vc->vc_sw = conswitchp;
#ifndef VT_SINGLE_DRIVER
        if (con_driver_map[num])
                vc->vc_sw = con_driver_map[num];
#endif
        __module_get(vc->vc_sw->owner);
        vc->vc_num = num;
        vc->vc_display_fg = &master_display_fg;
        if (vc->vc_uni_pagedir_loc)
                con_free_unimap(vc);
        vc->vc_uni_pagedir_loc = &vc->vc_uni_pagedir;
        vc->vc_uni_pagedir = NULL;
        vc->vc_hi_font_mask = 0;
        vc->vc_complement_mask = 0;
        vc->vc_can_do_color = 0;
        vc->vc_panic_force_write = false;
        vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
        vc->vc_sw->con_init(vc, init);
        if (!vc->vc_complement_mask)
                vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;
        vc->vc_s_complement_mask = vc->vc_complement_mask;
        vc->vc_size_row = vc->vc_cols << 1;
        vc->vc_screenbuf_size = vc->vc_rows * vc->vc_size_row;
}

int vc_allocate(unsigned int currcons)  /* return 0 on success */
{
        struct vt_notifier_param param;
        struct vc_data *vc;

        WARN_CONSOLE_UNLOCKED();

        if (currcons >= MAX_NR_CONSOLES)
                return -ENXIO;

        if (vc_cons[currcons].d)
                return 0;

        /* due to the granularity of kmalloc, we waste some memory here */
        /* the alloc is done in two steps, to optimize the common situation
           of a 25x80 console (structsize=216, screenbuf_size=4000) */
        /* although the numbers above are not valid since long ago, the
           point is still up-to-date and the comment still has its value
           even if only as a historical artifact.  --mj, July 1998 */
        param.vc = vc = kzalloc(sizeof(struct vc_data), GFP_KERNEL);
        if (!vc)
                return -ENOMEM;

        vc_cons[currcons].d = vc;
        tty_port_init(&vc->port);
        INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);

        visual_init(vc, currcons, 1);

        if (!*vc->vc_uni_pagedir_loc)
                con_set_default_unimap(vc);

        vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
        if (!vc->vc_screenbuf)
                goto err_free;

        /* If no drivers have overridden us and the user didn't pass a
           boot option, default to displaying the cursor */
        if (global_cursor_default == -1)
                global_cursor_default = 1;

        vc_init(vc, vc->vc_rows, vc->vc_cols, 1);
        vcs_make_sysfs(currcons);
        atomic_notifier_call_chain(&vt_notifier_list, VT_ALLOCATE, &param);

        return 0;
err_free:
        kfree(vc);
        vc_cons[currcons].d = NULL;
        return -ENOMEM;
}

static inline int resize_screen(struct vc_data *vc, int width, int height,
                                int user)
{
        /* Resizes the resolution of the display adapater */
        int err = 0;

        if (vc->vc_mode != KD_GRAPHICS && vc->vc_sw->con_resize)
                err = vc->vc_sw->con_resize(vc, width, height, user);

        return err;
}

/*
 * Change # of rows and columns (0 means unchanged/the size of fg_console)
 * [this is to be used together with some user program
 * like resize that changes the hardware videomode]
 */
#define VC_RESIZE_MAXCOL (32767)
#define VC_RESIZE_MAXROW (32767)

/**
 *      vc_do_resize    -       resizing method for the tty
 *      @tty: tty being resized
 *      @real_tty: real tty (different to tty if a pty/tty pair)
 *      @vc: virtual console private data
 *      @cols: columns
 *      @lines: lines
 *
 *      Resize a virtual console, clipping according to the actual constraints.
 *      If the caller passes a tty structure then update the termios winsize
 *      information and perform any necessary signal handling.
 *
 *      Caller must hold the console semaphore. Takes the termios rwsem and
 *      ctrl_lock of the tty IFF a tty is passed.
 */

static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
                                unsigned int cols, unsigned int lines)
{
        unsigned long old_origin, new_origin, new_scr_end, rlth, rrem, err = 0;
        unsigned long end;
        unsigned int old_rows, old_row_size, first_copied_row;
        unsigned int new_cols, new_rows, new_row_size, new_screen_size;
        unsigned int user;
        unsigned short *newscreen;
        struct uni_screen *new_uniscr = NULL;

        WARN_CONSOLE_UNLOCKED();

        if (!vc)
                return -ENXIO;

        user = vc->vc_resize_user;
        vc->vc_resize_user = 0;

        if (cols > VC_RESIZE_MAXCOL || lines > VC_RESIZE_MAXROW)
                return -EINVAL;

        new_cols = (cols ? cols : vc->vc_cols);
        new_rows = (lines ? lines : vc->vc_rows);
        new_row_size = new_cols << 1;
        new_screen_size = new_row_size * new_rows;

        if (new_cols == vc->vc_cols && new_rows == vc->vc_rows)
                return 0;

        if (new_screen_size > (4 << 20))
                return -EINVAL;
        newscreen = kzalloc(new_screen_size, GFP_USER);
        if (!newscreen)
                return -ENOMEM;

        if (get_vc_uniscr(vc)) {
                new_uniscr = vc_uniscr_alloc(new_cols, new_rows);
                if (!new_uniscr) {
                        kfree(newscreen);
                        return -ENOMEM;
                }
        }

        if (vc == sel_cons)
                clear_selection();

        old_rows = vc->vc_rows;
        old_row_size = vc->vc_size_row;

        err = resize_screen(vc, new_cols, new_rows, user);
        if (err) {
                kfree(newscreen);
                kfree(new_uniscr);
                return err;
        }

        vc->vc_rows = new_rows;
        vc->vc_cols = new_cols;
        vc->vc_size_row = new_row_size;
        vc->vc_screenbuf_size = new_screen_size;

        rlth = min(old_row_size, new_row_size);
        rrem = new_row_size - rlth;
        old_origin = vc->vc_origin;
        new_origin = (long) newscreen;
        new_scr_end = new_origin + new_screen_size;

        if (vc->vc_y > new_rows) {
                if (old_rows - vc->vc_y < new_rows) {
                        /*
                         * Cursor near the bottom, copy contents from the
                         * bottom of buffer
                         */
                        first_copied_row = (old_rows - new_rows);
                } else {
                        /*
                         * Cursor is in no man's land, copy 1/2 screenful
                         * from the top and bottom of cursor position
                         */
                        first_copied_row = (vc->vc_y - new_rows/2);
                }
                old_origin += first_copied_row * old_row_size;
        } else
                first_copied_row = 0;
        end = old_origin + old_row_size * min(old_rows, new_rows);

        vc_uniscr_copy_area(new_uniscr, new_cols, new_rows,
                            get_vc_uniscr(vc), rlth/2, first_copied_row,
                            min(old_rows, new_rows));
        vc_uniscr_set(vc, new_uniscr);

        update_attr(vc);

        while (old_origin < end) {
                scr_memcpyw((unsigned short *) new_origin,
                            (unsigned short *) old_origin, rlth);
                if (rrem)
                        scr_memsetw((void *)(new_origin + rlth),
                                    vc->vc_video_erase_char, rrem);
                old_origin += old_row_size;
                new_origin += new_row_size;
        }
        if (new_scr_end > new_origin)
                scr_memsetw((void *)new_origin, vc->vc_video_erase_char,
                            new_scr_end - new_origin);
        kfree(vc->vc_screenbuf);
        vc->vc_screenbuf = newscreen;
        vc->vc_screenbuf_size = new_screen_size;
        set_origin(vc);

        /* do part of a reset_terminal() */
        vc->vc_top = 0;
        vc->vc_bottom = vc->vc_rows;
        gotoxy(vc, vc->vc_x, vc->vc_y);
        save_cur(vc);

        if (tty) {
                /* Rewrite the requested winsize data with the actual
                   resulting sizes */
                struct winsize ws;
                memset(&ws, 0, sizeof(ws));
                ws.ws_row = vc->vc_rows;
                ws.ws_col = vc->vc_cols;
                ws.ws_ypixel = vc->vc_scan_lines;
                tty_do_resize(tty, &ws);
        }

        if (con_is_visible(vc))
                update_screen(vc);
        vt_event_post(VT_EVENT_RESIZE, vc->vc_num, vc->vc_num);
        return err;
}

/**
 *      vc_resize               -       resize a VT
 *      @vc: virtual console
 *      @cols: columns
 *      @rows: rows
 *
 *      Resize a virtual console as seen from the console end of things. We
 *      use the common vc_do_resize methods to update the structures. The
 *      caller must hold the console sem to protect console internals and
 *      vc->port.tty
 */

int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int rows)
{
        return vc_do_resize(vc->port.tty, vc, cols, rows);
}

/**
 *      vt_resize               -       resize a VT
 *      @tty: tty to resize
 *      @ws: winsize attributes
 *
 *      Resize a virtual terminal. This is called by the tty layer as we
 *      register our own handler for resizing. The mutual helper does all
 *      the actual work.
 *
 *      Takes the console sem and the called methods then take the tty
 *      termios_rwsem and the tty ctrl_lock in that order.
 */
static int vt_resize(struct tty_struct *tty, struct winsize *ws)
{
        struct vc_data *vc = tty->driver_data;
        int ret;

        console_lock();
        ret = vc_do_resize(tty, vc, ws->ws_col, ws->ws_row);
        console_unlock();
        return ret;
}

struct vc_data *vc_deallocate(unsigned int currcons)
{
        struct vc_data *vc = NULL;

        WARN_CONSOLE_UNLOCKED();

        if (vc_cons_allocated(currcons)) {
                struct vt_notifier_param param;

                param.vc = vc = vc_cons[currcons].d;
                atomic_notifier_call_chain(&vt_notifier_list, VT_DEALLOCATE, &param);
                vcs_remove_sysfs(currcons);
                vc->vc_sw->con_deinit(vc);
                put_pid(vc->vt_pid);
                module_put(vc->vc_sw->owner);
                vc_uniscr_set(vc, NULL);
                kfree(vc->vc_screenbuf);
                vc_cons[currcons].d = NULL;
        }
        return vc;
}

/*
 *      VT102 emulator
 */

#define set_kbd(vc, x)  vt_set_kbd_mode_bit((vc)->vc_num, (x))
#define clr_kbd(vc, x)  vt_clr_kbd_mode_bit((vc)->vc_num, (x))
#define is_kbd(vc, x)   vt_get_kbd_mode_bit((vc)->vc_num, (x))

#define decarm          VC_REPEAT
#define decckm          VC_CKMODE
#define kbdapplic       VC_APPLIC
#define lnm             VC_CRLF

/*
 * this is what the terminal answers to a ESC-Z or csi0c query.
 */
#define VT100ID "\033[?1;2c"
#define VT102ID "\033[?6c"

const unsigned char color_table[] = { 0, 4, 2, 6, 1, 5, 3, 7,
                                       8,12,10,14, 9,13,11,15 };

/* the default colour table, for VGA+ colour systems */
unsigned char default_red[] = {
        0x00, 0xaa, 0x00, 0xaa, 0x00, 0xaa, 0x00, 0xaa,
        0x55, 0xff, 0x55, 0xff, 0x55, 0xff, 0x55, 0xff
};
module_param_array(default_red, byte, NULL, S_IRUGO | S_IWUSR);

unsigned char default_grn[] = {
        0x00, 0x00, 0xaa, 0x55, 0x00, 0x00, 0xaa, 0xaa,
        0x55, 0x55, 0xff, 0xff, 0x55, 0x55, 0xff, 0xff
};
module_param_array(default_grn, byte, NULL, S_IRUGO | S_IWUSR);

unsigned char default_blu[] = {
        0x00, 0x00, 0x00, 0x00, 0xaa, 0xaa, 0xaa, 0xaa,
        0x55, 0x55, 0x55, 0x55, 0xff, 0xff, 0xff, 0xff
};
module_param_array(default_blu, byte, NULL, S_IRUGO | S_IWUSR);

/*
 * gotoxy() must verify all boundaries, because the arguments
 * might also be negative. If the given position is out of
 * bounds, the cursor is placed at the nearest margin.
 */
static void gotoxy(struct vc_data *vc, int new_x, int new_y)
{
        int min_y, max_y;

        if (new_x < 0)
                vc->vc_x = 0;
        else {
                if (new_x >= vc->vc_cols)
                        vc->vc_x = vc->vc_cols - 1;
                else
                        vc->vc_x = new_x;
        }

        if (vc->vc_decom) {
                min_y = vc->vc_top;
                max_y = vc->vc_bottom;
        } else {
                min_y = 0;
                max_y = vc->vc_rows;
        }
        if (new_y < min_y)
                vc->vc_y = min_y;
        else if (new_y >= max_y)
                vc->vc_y = max_y - 1;
        else
                vc->vc_y = new_y;
        vc->vc_pos = vc->vc_origin + vc->vc_y * vc->vc_size_row + (vc->vc_x<<1);
        vc->vc_need_wrap = 0;
}

/* for absolute user moves, when decom is set */
static void gotoxay(struct vc_data *vc, int new_x, int new_y)
{
        gotoxy(vc, new_x, vc->vc_decom ? (vc->vc_top + new_y) : new_y);
}

void scrollback(struct vc_data *vc)
{
        scrolldelta(-(vc->vc_rows / 2));
}

void scrollfront(struct vc_data *vc, int lines)
{
        if (!lines)
                lines = vc->vc_rows / 2;
        scrolldelta(lines);
}

static void lf(struct vc_data *vc)
{
        /* don't scroll if above bottom of scrolling region, or
         * if below scrolling region
         */
        if (vc->vc_y + 1 == vc->vc_bottom)
                con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_UP, 1);
        else if (vc->vc_y < vc->vc_rows - 1) {
                vc->vc_y++;
                vc->vc_pos += vc->vc_size_row;
        }
        vc->vc_need_wrap = 0;
        notify_write(vc, '\n');
}

static void ri(struct vc_data *vc)
{
        /* don't scroll if below top of scrolling region, or
         * if above scrolling region
         */
        if (vc->vc_y == vc->vc_top)
                con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_DOWN, 1);
        else if (vc->vc_y > 0) {
                vc->vc_y--;
                vc->vc_pos -= vc->vc_size_row;
        }
        vc->vc_need_wrap = 0;
}

static inline void cr(struct vc_data *vc)
{
        vc->vc_pos -= vc->vc_x << 1;
        vc->vc_need_wrap = vc->vc_x = 0;
        notify_write(vc, '\r');
}

static inline void bs(struct vc_data *vc)
{
        if (vc->vc_x) {
                vc->vc_pos -= 2;
                vc->vc_x--;
                vc->vc_need_wrap = 0;
                notify_write(vc, '\b');
        }
}

static inline void del(struct vc_data *vc)
{
        /* ignored */
}

static void csi_J(struct vc_data *vc, int vpar)
{
        unsigned int count;
        unsigned short * start;

        switch (vpar) {
                case 0: /* erase from cursor to end of display */
                        vc_uniscr_clear_line(vc, vc->vc_x,
                                             vc->vc_cols - vc->vc_x);
                        vc_uniscr_clear_lines(vc, vc->vc_y + 1,
                                              vc->vc_rows - vc->vc_y - 1);
                        count = (vc->vc_scr_end - vc->vc_pos) >> 1;
                        start = (unsigned short *)vc->vc_pos;
                        break;
                case 1: /* erase from start to cursor */
                        vc_uniscr_clear_line(vc, 0, vc->vc_x + 1);
                        vc_uniscr_clear_lines(vc, 0, vc->vc_y);
                        count = ((vc->vc_pos - vc->vc_origin) >> 1) + 1;
                        start = (unsigned short *)vc->vc_origin;
                        break;
                case 2: /* erase whole display */
                case 3: /* (and scrollback buffer later) */
                        vc_uniscr_clear_lines(vc, 0, vc->vc_rows);
                        count = vc->vc_cols * vc->vc_rows;
                        start = (unsigned short *)vc->vc_origin;
                        break;
                default:
                        return;
        }
        scr_memsetw(start, vc->vc_video_erase_char, 2 * count);
        if (vpar == 3) {
                set_origin(vc);
                flush_scrollback(vc);
                if (con_is_visible(vc))
                        update_screen(vc);
        } else if (con_should_update(vc))
                do_update_region(vc, (unsigned long) start, count);
        vc->vc_need_wrap = 0;
}

static void csi_K(struct vc_data *vc, int vpar)
{
        unsigned int count;
        unsigned short *start = (unsigned short *)vc->vc_pos;
        int offset;

        switch (vpar) {
                case 0: /* erase from cursor to end of line */
                        offset = 0;
                        count = vc->vc_cols - vc->vc_x;
                        break;
                case 1: /* erase from start of line to cursor */
                        offset = -vc->vc_x;
                        count = vc->vc_x + 1;
                        break;
                case 2: /* erase whole line */
                        offset = -vc->vc_x;
                        count = vc->vc_cols;
                        break;
                default:
                        return;
        }
        vc_uniscr_clear_line(vc, vc->vc_x + offset, count);
        scr_memsetw(start + offset, vc->vc_video_erase_char, 2 * count);
        vc->vc_need_wrap = 0;
        if (con_should_update(vc))
                do_update_region(vc, (unsigned long) start, count);
}

static void csi_X(struct vc_data *vc, int vpar) /* erase the following vpar positions */
{                                         /* not vt100? */
        int count;

        if (!vpar)
                vpar++;
        count = (vpar > vc->vc_cols - vc->vc_x) ? (vc->vc_cols - vc->vc_x) : vpar;

        vc_uniscr_clear_line(vc, vc->vc_x, count);
        scr_memsetw((unsigned short *)vc->vc_pos, vc->vc_video_erase_char, 2 * count);
        if (con_should_update(vc))
                vc->vc_sw->con_clear(vc, vc->vc_y, vc->vc_x, 1, count);
        vc->vc_need_wrap = 0;
}

static void default_attr(struct vc_data *vc)
{
        vc->vc_intensity = 1;
        vc->vc_italic = 0;
        vc->vc_underline = 0;
        vc->vc_reverse = 0;
        vc->vc_blink = 0;
        vc->vc_color = vc->vc_def_color;
}

struct rgb { u8 r; u8 g; u8 b; };

static void rgb_from_256(int i, struct rgb *c)
{
        if (i < 8) {            /* Standard colours. */
                c->r = i&1 ? 0xaa : 0x00;
                c->g = i&2 ? 0xaa : 0x00;
                c->b = i&4 ? 0xaa : 0x00;
        } else if (i < 16) {
                c->r = i&1 ? 0xff : 0x55;
                c->g = i&2 ? 0xff : 0x55;
                c->b = i&4 ? 0xff : 0x55;
        } else if (i < 232) {   /* 6x6x6 colour cube. */
                c->r = (i - 16) / 36 * 85 / 2;
                c->g = (i - 16) / 6 % 6 * 85 / 2;
                c->b = (i - 16) % 6 * 85 / 2;
        } else                  /* Grayscale ramp. */
                c->r = c->g = c->b = i * 10 - 2312;
}

static void rgb_foreground(struct vc_data *vc, const struct rgb *c)
{
        u8 hue = 0, max = max3(c->r, c->g, c->b);

        if (c->r > max / 2)
                hue |= 4;
        if (c->g > max / 2)
                hue |= 2;
        if (c->b > max / 2)
                hue |= 1;

        if (hue == 7 && max <= 0x55) {
                hue = 0;
                vc->vc_intensity = 2;
        } else if (max > 0xaa)
                vc->vc_intensity = 2;
        else
                vc->vc_intensity = 1;

        vc->vc_color = (vc->vc_color & 0xf0) | hue;
}

static void rgb_background(struct vc_data *vc, const struct rgb *c)
{
        /* For backgrounds, err on the dark side. */
        vc->vc_color = (vc->vc_color & 0x0f)
                | (c->r&0x80) >> 1 | (c->g&0x80) >> 2 | (c->b&0x80) >> 3;
}

/*
 * ITU T.416 Higher colour modes. They break the usual properties of SGR codes
 * and thus need to be detected and ignored by hand. Strictly speaking, that
 * standard also wants : rather than ; as separators, contrary to ECMA-48, but
 * no one produces such codes and almost no one accepts them.
 *
 * Subcommands 3 (CMY) and 4 (CMYK) are so insane there's no point in
 * supporting them.
 */
static int vc_t416_color(struct vc_data *vc, int i,
                void(*set_color)(struct vc_data *vc, const struct rgb *c))
{
        struct rgb c;

        i++;
        if (i > vc->vc_npar)
                return i;

        if (vc->vc_par[i] == 5 && i + 1 <= vc->vc_npar) {
                /* 256 colours */
                i++;
                rgb_from_256(vc->vc_par[i], &c);
        } else if (vc->vc_par[i] == 2 && i + 3 <= vc->vc_npar) {
                /* 24 bit */
                c.r = vc->vc_par[i + 1];
                c.g = vc->vc_par[i + 2];
                c.b = vc->vc_par[i + 3];
                i += 3;
        } else
                return i;

        set_color(vc, &c);

        return i;
}

/* console_lock is held */
static void csi_m(struct vc_data *vc)
{
        int i;

        for (i = 0; i <= vc->vc_npar; i++)
                switch (vc->vc_par[i]) {
                case 0: /* all attributes off */
                        default_attr(vc);
                        break;
                case 1:
                        vc->vc_intensity = 2;
                        break;
                case 2:
                        vc->vc_intensity = 0;
                        break;
                case 3:
                        vc->vc_italic = 1;
                        break;
                case 21:
                        /*
                         * No console drivers support double underline, so
                         * convert it to a single underline.
                         */
                case 4:
                        vc->vc_underline = 1;
                        break;
                case 5:
                        vc->vc_blink = 1;
                        break;
                case 7:
                        vc->vc_reverse = 1;
                        break;
                case 10: /* ANSI X3.64-1979 (SCO-ish?)
                          * Select primary font, don't display control chars if
                          * defined, don't set bit 8 on output.
                          */
                        vc->vc_translate = set_translate(vc->vc_charset == 0
                                        ? vc->vc_G0_charset
                                        : vc->vc_G1_charset, vc);
                        vc->vc_disp_ctrl = 0;
                        vc->vc_toggle_meta = 0;
                        break;
                case 11: /* ANSI X3.64-1979 (SCO-ish?)
                          * Select first alternate font, lets chars < 32 be
                          * displayed as ROM chars.
                          */
                        vc->vc_translate = set_translate(IBMPC_MAP, vc);
                        vc->vc_disp_ctrl = 1;
                        vc->vc_toggle_meta = 0;
                        break;
                case 12: /* ANSI X3.64-1979 (SCO-ish?)
                          * Select second alternate font, toggle high bit
                          * before displaying as ROM char.
                          */
                        vc->vc_translate = set_translate(IBMPC_MAP, vc);
                        vc->vc_disp_ctrl = 1;
                        vc->vc_toggle_meta = 1;
                        break;
                case 22:
                        vc->vc_intensity = 1;
                        break;
                case 23:
                        vc->vc_italic = 0;
                        break;
                case 24:
                        vc->vc_underline = 0;
                        break;
                case 25:
                        vc->vc_blink = 0;
                        break;
                case 27:
                        vc->vc_reverse = 0;
                        break;
                case 38:
                        i = vc_t416_color(vc, i, rgb_foreground);
                        break;
                case 48:
                        i = vc_t416_color(vc, i, rgb_background);
                        break;
                case 39:
                        vc->vc_color = (vc->vc_def_color & 0x0f) |
                                (vc->vc_color & 0xf0);
                        break;
                case 49:
                        vc->vc_color = (vc->vc_def_color & 0xf0) |
                                (vc->vc_color & 0x0f);
                        break;
                default:
                        if (vc->vc_par[i] >= 90 && vc->vc_par[i] <= 107) {
                                if (vc->vc_par[i] < 100)
                                        vc->vc_intensity = 2;
                                vc->vc_par[i] -= 60;
                        }
                        if (vc->vc_par[i] >= 30 && vc->vc_par[i] <= 37)
                                vc->vc_color = color_table[vc->vc_par[i] - 30]
                                        | (vc->vc_color & 0xf0);
                        else if (vc->vc_par[i] >= 40 && vc->vc_par[i] <= 47)
                                vc->vc_color = (color_table[vc->vc_par[i] - 40] << 4)
                                        | (vc->vc_color & 0x0f);
                        break;
                }
        update_attr(vc);
}

static void respond_string(const char *p, struct tty_port *port)
{
        while (*p) {
                tty_insert_flip_char(port, *p, 0);
                p++;
        }
        tty_schedule_flip(port);
}

static void cursor_report(struct vc_data *vc, struct tty_struct *tty)
{
        char buf[40];

        sprintf(buf, "\033[%d;%dR", vc->vc_y + (vc->vc_decom ? vc->vc_top + 1 : 1), vc->vc_x + 1);
        respond_string(buf, tty->port);
}

static inline void status_report(struct tty_struct *tty)
{
        respond_string("\033[0n", tty->port);   /* Terminal ok */
}

static inline void respond_ID(struct tty_struct *tty)
{
        respond_string(VT102ID, tty->port);
}

void mouse_report(struct tty_struct *tty, int butt, int mrx, int mry)
{
        char buf[8];

        sprintf(buf, "\033[M%c%c%c", (char)(' ' + butt), (char)('!' + mrx),
                (char)('!' + mry));
        respond_string(buf, tty->port);
}

/* invoked via ioctl(TIOCLINUX) and through set_selection */
int mouse_reporting(void)
{
        return vc_cons[fg_console].d->vc_report_mouse;
}

/* console_lock is held */
static void set_mode(struct vc_data *vc, int on_off)
{
        int i;

        for (i = 0; i <= vc->vc_npar; i++)
                if (vc->vc_ques) {
                        switch(vc->vc_par[i]) { /* DEC private modes set/reset */
                        case 1:                 /* Cursor keys send ^[Ox/^[[x */
                                if (on_off)
                                        set_kbd(vc, decckm);
                                else
                                        clr_kbd(vc, decckm);
                                break;
                        case 3: /* 80/132 mode switch unimplemented */
#if 0
                                vc_resize(deccolm ? 132 : 80, vc->vc_rows);
                                /* this alone does not suffice; some user mode
                                   utility has to change the hardware regs */
#endif
                                break;
                        case 5:                 /* Inverted screen on/off */
                                if (vc->vc_decscnm != on_off) {
                                        vc->vc_decscnm = on_off;
                                        invert_screen(vc, 0, vc->vc_screenbuf_size, 0);
                                        update_attr(vc);
                                }
                                break;
                        case 6:                 /* Origin relative/absolute */
                                vc->vc_decom = on_off;
                                gotoxay(vc, 0, 0);
                                break;
                        case 7:                 /* Autowrap on/off */
                                vc->vc_decawm = on_off;
                                break;
                        case 8:                 /* Autorepeat on/off */
                                if (on_off)
                                        set_kbd(vc, decarm);
                                else
                                        clr_kbd(vc, decarm);
                                break;
                        case 9:
                                vc->vc_report_mouse = on_off ? 1 : 0;
                                break;
                        case 25:                /* Cursor on/off */
                                vc->vc_deccm = on_off;
                                break;
                        case 1000:
                                vc->vc_report_mouse = on_off ? 2 : 0;
                                break;
                        }
                } else {
                        switch(vc->vc_par[i]) { /* ANSI modes set/reset */
                        case 3:                 /* Monitor (display ctrls) */
                                vc->vc_disp_ctrl = on_off;
                                break;
                        case 4:                 /* Insert Mode on/off */
                                vc->vc_decim = on_off;
                                break;
                        case 20:                /* Lf, Enter == CrLf/Lf */
                                if (on_off)
                                        set_kbd(vc, lnm);
                                else
                                        clr_kbd(vc, lnm);
                                break;
                        }
                }
}

/* console_lock is held */
static void setterm_command(struct vc_data *vc)
{
        switch(vc->vc_par[0]) {
                case 1: /* set color for underline mode */
                        if (vc->vc_can_do_color &&
                                        vc->vc_par[1] < 16) {
                                vc->vc_ulcolor = color_table[vc->vc_par[1]];
                                if (vc->vc_underline)
                                        update_attr(vc);
                        }
                        break;
                case 2: /* set color for half intensity mode */
                        if (vc->vc_can_do_color &&
                                        vc->vc_par[1] < 16) {
                                vc->vc_halfcolor = color_table[vc->vc_par[1]];
                                if (vc->vc_intensity == 0)
                                        update_attr(vc);
                        }
                        break;
                case 8: /* store colors as defaults */
                        vc->vc_def_color = vc->vc_attr;
                        if (vc->vc_hi_font_mask == 0x100)
                                vc->vc_def_color >>= 1;
                        default_attr(vc);
                        update_attr(vc);
                        break;
                case 9: /* set blanking interval */
                        blankinterval = ((vc->vc_par[1] < 60) ? vc->vc_par[1] : 60) * 60;
                        poke_blanked_console();
                        break;
                case 10: /* set bell frequency in Hz */
                        if (vc->vc_npar >= 1)
                                vc->vc_bell_pitch = vc->vc_par[1];
                        else
                                vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
                        break;
                case 11: /* set bell duration in msec */
                        if (vc->vc_npar >= 1)
                                vc->vc_bell_duration = (vc->vc_par[1] < 2000) ?
                                        msecs_to_jiffies(vc->vc_par[1]) : 0;
                        else
                                vc->vc_bell_duration = DEFAULT_BELL_DURATION;
                        break;
                case 12: /* bring specified console to the front */
                        if (vc->vc_par[1] >= 1 && vc_cons_allocated(vc->vc_par[1] - 1))
                                set_console(vc->vc_par[1] - 1);
                        break;
                case 13: /* unblank the screen */
                        poke_blanked_console();
                        break;
                case 14: /* set vesa powerdown interval */
                        vesa_off_interval = ((vc->vc_par[1] < 60) ? vc->vc_par[1] : 60) * 60 * HZ;
                        break;
                case 15: /* activate the previous console */
                        set_console(last_console);
                        break;
                case 16: /* set cursor blink duration in msec */
                        if (vc->vc_npar >= 1 && vc->vc_par[1] >= 50 &&
                                        vc->vc_par[1] <= USHRT_MAX)
                                vc->vc_cur_blink_ms = vc->vc_par[1];
                        else
                                vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
                        break;
        }
}

/* console_lock is held */
static void csi_at(struct vc_data *vc, unsigned int nr)
{
        if (nr > vc->vc_cols - vc->vc_x)
                nr = vc->vc_cols - vc->vc_x;
        else if (!nr)
                nr = 1;
        insert_char(vc, nr);
}

/* console_lock is held */
static void csi_L(struct vc_data *vc, unsigned int nr)
{
        if (nr > vc->vc_rows - vc->vc_y)
                nr = vc->vc_rows - vc->vc_y;
        else if (!nr)
                nr = 1;
        con_scroll(vc, vc->vc_y, vc->vc_bottom, SM_DOWN, nr);
        vc->vc_need_wrap = 0;
}

/* console_lock is held */
static void csi_P(struct vc_data *vc, unsigned int nr)
{
        if (nr > vc->vc_cols - vc->vc_x)
                nr = vc->vc_cols - vc->vc_x;
        else if (!nr)
                nr = 1;
        delete_char(vc, nr);
}

/* console_lock is held */
static void csi_M(struct vc_data *vc, unsigned int nr)
{
        if (nr > vc->vc_rows - vc->vc_y)
                nr = vc->vc_rows - vc->vc_y;
        else if (!nr)
                nr=1;
        con_scroll(vc, vc->vc_y, vc->vc_bottom, SM_UP, nr);
        vc->vc_need_wrap = 0;
}

/* console_lock is held (except via vc_init->reset_terminal */
static void save_cur(struct vc_data *vc)
{
        vc->vc_saved_x          = vc->vc_x;
        vc->vc_saved_y          = vc->vc_y;
        vc->vc_s_intensity      = vc->vc_intensity;
        vc->vc_s_italic         = vc->vc_italic;
        vc->vc_s_underline      = vc->vc_underline;
        vc->vc_s_blink          = vc->vc_blink;

        vc->vc_s_reverse        = vc->vc_reverse;
        vc->vc_s_charset        = vc->vc_charset;
        vc->vc_s_color          = vc->vc_color;
        vc->vc_saved_G0         = vc->vc_G0_charset;
        vc->vc_saved_G1         = vc->vc_G1_charset;
}

/* console_lock is held */
static void restore_cur(struct vc_data *vc)
{
        gotoxy(vc, vc->vc_saved_x, vc->vc_saved_y);
        vc->vc_intensity        = vc->vc_s_intensity;
        vc->vc_italic           = vc->vc_s_italic;
        vc->vc_underline        = vc->vc_s_underline;
        vc->vc_blink            = vc->vc_s_blink;
        vc->vc_reverse          = vc->vc_s_reverse;
        vc->vc_charset          = vc->vc_s_charset;
        vc->vc_color            = vc->vc_s_color;
        vc->vc_G0_charset       = vc->vc_saved_G0;
        vc->vc_G1_charset       = vc->vc_saved_G1;
        vc->vc_translate        = set_translate(vc->vc_charset ? vc->vc_G1_charset : vc->vc_G0_charset, vc);
        update_attr(vc);
        vc->vc_need_wrap = 0;
}

enum { ESnormal, ESesc, ESsquare, ESgetpars, ESfunckey,
        EShash, ESsetG0, ESsetG1, ESpercent, ESignore, ESnonstd,
        ESpalette, ESosc };

/* console_lock is held (except via vc_init()) */
static void reset_terminal(struct vc_data *vc, int do_clear)
{
        vc->vc_top              = 0;
        vc->vc_bottom           = vc->vc_rows;
        vc->vc_state            = ESnormal;
        vc->vc_ques             = 0;
        vc->vc_translate        = set_translate(LAT1_MAP, vc);
        vc->vc_G0_charset       = LAT1_MAP;
        vc->vc_G1_charset       = GRAF_MAP;
        vc->vc_charset          = 0;
        vc->vc_need_wrap        = 0;
        vc->vc_report_mouse     = 0;
        vc->vc_utf              = default_utf8;
        vc->vc_utf_count        = 0;

        vc->vc_disp_ctrl        = 0;
        vc->vc_toggle_meta      = 0;

        vc->vc_decscnm          = 0;
        vc->vc_decom            = 0;
        vc->vc_decawm           = 1;
        vc->vc_deccm            = global_cursor_default;
        vc->vc_decim            = 0;

        vt_reset_keyboard(vc->vc_num);

        vc->vc_cursor_type = cur_default;
        vc->vc_complement_mask = vc->vc_s_complement_mask;

        default_attr(vc);
        update_attr(vc);

        vc->vc_tab_stop[0]      =
        vc->vc_tab_stop[1]      =
        vc->vc_tab_stop[2]      =
        vc->vc_tab_stop[3]      =
        vc->vc_tab_stop[4]      =
        vc->vc_tab_stop[5]      =
        vc->vc_tab_stop[6]      =
        vc->vc_tab_stop[7]      = 0x01010101;

        vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
        vc->vc_bell_duration = DEFAULT_BELL_DURATION;
        vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;

        gotoxy(vc, 0, 0);
        save_cur(vc);
        if (do_clear)
            csi_J(vc, 2);
}

/* console_lock is held */
static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
{
        /*
         *  Control characters can be used in the _middle_
         *  of an escape sequence.
         */
        if (vc->vc_state == ESosc && c>=8 && c<=13) /* ... except for OSC */
                return;
        switch (c) {
        case 0:
                return;
        case 7:
                if (vc->vc_state == ESosc)
                        vc->vc_state = ESnormal;
                else if (vc->vc_bell_duration)
                        kd_mksound(vc->vc_bell_pitch, vc->vc_bell_duration);
                return;
        case 8:
                bs(vc);
                return;
        case 9:
                vc->vc_pos -= (vc->vc_x << 1);
                while (vc->vc_x < vc->vc_cols - 1) {
                        vc->vc_x++;
                        if (vc->vc_tab_stop[7 & (vc->vc_x >> 5)] & (1 << (vc->vc_x & 31)))
                                break;
                }
                vc->vc_pos += (vc->vc_x << 1);
                notify_write(vc, '\t');
                return;
        case 10: case 11: case 12:
                lf(vc);
                if (!is_kbd(vc, lnm))
                        return;
        case 13:
                cr(vc);
                return;
        case 14:
                vc->vc_charset = 1;
                vc->vc_translate = set_translate(vc->vc_G1_charset, vc);
                vc->vc_disp_ctrl = 1;
                return;
        case 15:
                vc->vc_charset = 0;
                vc->vc_translate = set_translate(vc->vc_G0_charset, vc);
                vc->vc_disp_ctrl = 0;
                return;
        case 24: case 26:
                vc->vc_state = ESnormal;
                return;
        case 27:
                vc->vc_state = ESesc;
                return;
        case 127:
                del(vc);
                return;
        case 128+27:
                vc->vc_state = ESsquare;
                return;
        }
        switch(vc->vc_state) {
        case ESesc:
                vc->vc_state = ESnormal;
                switch (c) {
                case '[':
                        vc->vc_state = ESsquare;
                        return;
                case ']':
                        vc->vc_state = ESnonstd;
                        return;
                case '%':
                        vc->vc_state = ESpercent;
                        return;
                case 'E':
                        cr(vc);
                        lf(vc);
                        return;
                case 'M':
                        ri(vc);
                        return;
                case 'D':
                        lf(vc);
                        return;
                case 'H':
                        vc->vc_tab_stop[7 & (vc->vc_x >> 5)] |= (1 << (vc->vc_x & 31));
                        return;
                case 'Z':
                        respond_ID(tty);
                        return;
                case '7':
                        save_cur(vc);
                        return;
                case '8':
                        restore_cur(vc);
                        return;
                case '(':
                        vc->vc_state = ESsetG0;
                        return;
                case ')':
                        vc->vc_state = ESsetG1;
                        return;
                case '#':
                        vc->vc_state = EShash;
                        return;
                case 'c':
                        reset_terminal(vc, 1);
                        return;
                case '>':  /* Numeric keypad */
                        clr_kbd(vc, kbdapplic);
                        return;
                case '=':  /* Appl. keypad */
                        set_kbd(vc, kbdapplic);
                        return;
                }
                return;
        case ESnonstd:
                if (c=='P') {   /* palette escape sequence */
                        for (vc->vc_npar = 0; vc->vc_npar < NPAR; vc->vc_npar++)
                                vc->vc_par[vc->vc_npar] = 0;
                        vc->vc_npar = 0;
                        vc->vc_state = ESpalette;
                        return;
                } else if (c=='R') {   /* reset palette */
                        reset_palette(vc);
                        vc->vc_state = ESnormal;
                } else if (c>='0' && c<='9')
                        vc->vc_state = ESosc;
                else
                        vc->vc_state = ESnormal;
                return;
        case ESpalette:
                if (isxdigit(c)) {
                        vc->vc_par[vc->vc_npar++] = hex_to_bin(c);
                        if (vc->vc_npar == 7) {
                                int i = vc->vc_par[0] * 3, j = 1;
                                vc->vc_palette[i] = 16 * vc->vc_par[j++];
                                vc->vc_palette[i++] += vc->vc_par[j++];
                                vc->vc_palette[i] = 16 * vc->vc_par[j++];
                                vc->vc_palette[i++] += vc->vc_par[j++];
                                vc->vc_palette[i] = 16 * vc->vc_par[j++];
                                vc->vc_palette[i] += vc->vc_par[j];
                                set_palette(vc);
                                vc->vc_state = ESnormal;
                        }
                } else
                        vc->vc_state = ESnormal;
                return;
        case ESsquare:
                for (vc->vc_npar = 0; vc->vc_npar < NPAR; vc->vc_npar++)
                        vc->vc_par[vc->vc_npar] = 0;
                vc->vc_npar = 0;
                vc->vc_state = ESgetpars;
                if (c == '[') { /* Function key */
                        vc->vc_state=ESfunckey;
                        return;
                }
                vc->vc_ques = (c == '?');
                if (vc->vc_ques)
                        return;
        case ESgetpars:
                if (c == ';' && vc->vc_npar < NPAR - 1) {
                        vc->vc_npar++;
                        return;
                } else if (c>='0' && c<='9') {
                        vc->vc_par[vc->vc_npar] *= 10;
                        vc->vc_par[vc->vc_npar] += c - '0';
                        return;
                }
                vc->vc_state = ESnormal;
                switch(c) {
                case 'h':
                        set_mode(vc, 1);
                        return;
                case 'l':
                        set_mode(vc, 0);
                        return;
                case 'c':
                        if (vc->vc_ques) {
                                if (vc->vc_par[0])
                                        vc->vc_cursor_type = vc->vc_par[0] | (vc->vc_par[1] << 8) | (vc->vc_par[2] << 16);
                                else
                                        vc->vc_cursor_type = cur_default;
                                return;
                        }
                        break;
                case 'm':
                        if (vc->vc_ques) {
                                clear_selection();
                                if (vc->vc_par[0])
                                        vc->vc_complement_mask = vc->vc_par[0] << 8 | vc->vc_par[1];
                                else
                                        vc->vc_complement_mask = vc->vc_s_complement_mask;
                                return;
                        }
                        break;
                case 'n':
                        if (!vc->vc_ques) {
                                if (vc->vc_par[0] == 5)
                                        status_report(tty);
                                else if (vc->vc_par[0] == 6)
                                        cursor_report(vc, tty);
                        }
                        return;
                }
                if (vc->vc_ques) {
                        vc->vc_ques = 0;
                        return;
                }
                switch(c) {
                case 'G': case '`':
                        if (vc->vc_par[0])
                                vc->vc_par[0]--;
                        gotoxy(vc, vc->vc_par[0], vc->vc_y);
                        return;
                case 'A':
                        if (!vc->vc_par[0])
                                vc->vc_par[0]++;
                        gotoxy(vc, vc->vc_x, vc->vc_y - vc->vc_par[0]);
                        return;
                case 'B': case 'e':
                        if (!vc->vc_par[0])
                                vc->vc_par[0]++;
                        gotoxy(vc, vc->vc_x, vc->vc_y + vc->vc_par[0]);
                        return;
                case 'C': case 'a':
                        if (!vc->vc_par[0])
                                vc->vc_par[0]++;
                        gotoxy(vc, vc->vc_x + vc->vc_par[0], vc->vc_y);
                        return;
                case 'D':
                        if (!vc->vc_par[0])
                                vc->vc_par[0]++;
                        gotoxy(vc, vc->vc_x - vc->vc_par[0], vc->vc_y);
                        return;
                case 'E':
                        if (!vc->vc_par[0])
                                vc->vc_par[0]++;
                        gotoxy(vc, 0, vc->vc_y + vc->vc_par[0]);
                        return;
                case 'F':
                        if (!vc->vc_par[0])
                                vc->vc_par[0]++;
                        gotoxy(vc, 0, vc->vc_y - vc->vc_par[0]);
                        return;
                case 'd':
                        if (vc->vc_par[0])
                                vc->vc_par[0]--;
                        gotoxay(vc, vc->vc_x ,vc->vc_par[0]);
                        return;
                case 'H': case 'f':
                        if (vc->vc_par[0])
                                vc->vc_par[0]--;
                        if (vc->vc_par[1])
                                vc->vc_par[1]--;
                        gotoxay(vc, vc->vc_par[1], vc->vc_par[0]);
                        return;
                case 'J':
                        csi_J(vc, vc->vc_par[0]);
                        return;
                case 'K':
                        csi_K(vc, vc->vc_par[0]);
                        return;
                case 'L':
                        csi_L(vc, vc->vc_par[0]);
                        return;
                case 'M':
                        csi_M(vc, vc->vc_par[0]);
                        return;
                case 'P':
                        csi_P(vc, vc->vc_par[0]);
                        return;
                case 'c':
                        if (!vc->vc_par[0])
                                respond_ID(tty);
                        return;
                case 'g':
                        if (!vc->vc_par[0])
                                vc->vc_tab_stop[7 & (vc->vc_x >> 5)] &= ~(1 << (vc->vc_x & 31));
                        else if (vc->vc_par[0] == 3) {
                                vc->vc_tab_stop[0] =
                                        vc->vc_tab_stop[1] =
                                        vc->vc_tab_stop[2] =
                                        vc->vc_tab_stop[3] =
                                        vc->vc_tab_stop[4] =
                                        vc->vc_tab_stop[5] =
                                        vc->vc_tab_stop[6] =
                                        vc->vc_tab_stop[7] = 0;
                        }
                        return;
                case 'm':
                        csi_m(vc);
                        return;
                case 'q': /* DECLL - but only 3 leds */
                        /* map 0,1,2,3 to 0,1,2,4 */
                        if (vc->vc_par[0] < 4)
                                vt_set_led_state(vc->vc_num,
                                            (vc->vc_par[0] < 3) ? vc->vc_par[0] : 4);
                        return;
                case 'r':
                        if (!vc->vc_par[0])
                                vc->vc_par[0]++;
                        if (!vc->vc_par[1])
                                vc->vc_par[1] = vc->vc_rows;
                        /* Minimum allowed region is 2 lines */
                        if (vc->vc_par[0] < vc->vc_par[1] &&
                            vc->vc_par[1] <= vc->vc_rows) {
                                vc->vc_top = vc->vc_par[0] - 1;
                                vc->vc_bottom = vc->vc_par[1];
                                gotoxay(vc, 0, 0);
                        }
                        return;
                case 's':
                        save_cur(vc);
                        return;
                case 'u':
                        restore_cur(vc);
                        return;
                case 'X':
                        csi_X(vc, vc->vc_par[0]);
                        return;
                case '@':
                        csi_at(vc, vc->vc_par[0]);
                        return;
                case ']': /* setterm functions */
                        setterm_command(vc);
                        return;
                }
                return;
        case ESpercent:
                vc->vc_state = ESnormal;
                switch (c) {
                case '@':  /* defined in ISO 2022 */
                        vc->vc_utf = 0;
                        return;
                case 'G':  /* prelim official escape code */
                case '8':  /* retained for compatibility */
                        vc->vc_utf = 1;
                        return;
                }
                return;
        case ESfunckey:
                vc->vc_state = ESnormal;
                return;
        case EShash:
                vc->vc_state = ESnormal;
                if (c == '8') {
                        /* DEC screen alignment test. kludge :-) */
                        vc->vc_video_erase_char =
                                (vc->vc_video_erase_char & 0xff00) | 'E';
                        csi_J(vc, 2);
                        vc->vc_video_erase_char =
                                (vc->vc_video_erase_char & 0xff00) | ' ';
                        do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
                }
                return;
        case ESsetG0:
                if (c == '0')
                        vc->vc_G0_charset = GRAF_MAP;
                else if (c == 'B')
                        vc->vc_G0_charset = LAT1_MAP;
                else if (c == 'U')
                        vc->vc_G0_charset = IBMPC_MAP;
                else if (c == 'K')
                        vc->vc_G0_charset = USER_MAP;
                if (vc->vc_charset == 0)
                        vc->vc_translate = set_translate(vc->vc_G0_charset, vc);
                vc->vc_state = ESnormal;
                return;
        case ESsetG1:
                if (c == '0')
                        vc->vc_G1_charset = GRAF_MAP;
                else if (c == 'B')
                        vc->vc_G1_charset = LAT1_MAP;
                else if (c == 'U')
                        vc->vc_G1_charset = IBMPC_MAP;
                else if (c == 'K')
                        vc->vc_G1_charset = USER_MAP;
                if (vc->vc_charset == 1)
                        vc->vc_translate = set_translate(vc->vc_G1_charset, vc);
                vc->vc_state = ESnormal;
                return;
        case ESosc:
                return;
        default:
                vc->vc_state = ESnormal;
        }
}

/* is_double_width() is based on the wcwidth() implementation by
 * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
 * Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
 */
struct interval {
        uint32_t first;
        uint32_t last;
};

static int ucs_cmp(const void *key, const void *elt)
{
        uint32_t ucs = *(uint32_t *)key;
        struct interval e = *(struct interval *) elt;

        if (ucs > e.last)
                return 1;
        else if (ucs < e.first)
                return -1;
        return 0;
}

static int is_double_width(uint32_t ucs)
{
        static const struct interval double_width[] = {
                { 0x1100, 0x115F }, { 0x2329, 0x232A }, { 0x2E80, 0x303E },
                { 0x3040, 0xA4CF }, { 0xAC00, 0xD7A3 }, { 0xF900, 0xFAFF },
                { 0xFE10, 0xFE19 }, { 0xFE30, 0xFE6F }, { 0xFF00, 0xFF60 },
                { 0xFFE0, 0xFFE6 }, { 0x20000, 0x2FFFD }, { 0x30000, 0x3FFFD }
        };
        if (ucs < double_width[0].first ||
            ucs > double_width[ARRAY_SIZE(double_width) - 1].last)
                return 0;

        return bsearch(&ucs, double_width, ARRAY_SIZE(double_width),
                        sizeof(struct interval), ucs_cmp) != NULL;
}

static void con_flush(struct vc_data *vc, unsigned long draw_from,
                unsigned long draw_to, int *draw_x)
{
        if (*draw_x < 0)
                return;

        vc->vc_sw->con_putcs(vc, (u16 *)draw_from,
                        (u16 *)draw_to - (u16 *)draw_from, vc->vc_y, *draw_x);
        *draw_x = -1;
}

/* acquires console_lock */
static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
        int c, next_c, tc, ok, n = 0, draw_x = -1;
        unsigned int currcons;
        unsigned long draw_from = 0, draw_to = 0;
        struct vc_data *vc;
        unsigned char vc_attr;
        struct vt_notifier_param param;
        uint8_t rescan;
        uint8_t inverse;
        uint8_t width;
        u16 himask, charmask;

        if (in_interrupt())
                return count;

        might_sleep();

        console_lock();
        vc = tty->driver_data;
        if (vc == NULL) {
                pr_err("vt: argh, driver_data is NULL !\n");
                console_unlock();
                return 0;
        }

        currcons = vc->vc_num;
        if (!vc_cons_allocated(currcons)) {
                /* could this happen? */
                pr_warn_once("con_write: tty %d not allocated\n", currcons+1);
                console_unlock();
                return 0;
        }

        himask = vc->vc_hi_font_mask;
        charmask = himask ? 0x1ff : 0xff;

        /* undraw cursor first */
        if (con_is_fg(vc))
                hide_cursor(vc);

        param.vc = vc;

        while (!tty->stopped && count) {
                int orig = *buf;
                c = orig;
                buf++;
                n++;
                count--;
                rescan = 0;
                inverse = 0;
                width = 1;

                /* Do no translation at all in control states */
                if (vc->vc_state != ESnormal) {
                        tc = c;
                } else if (vc->vc_utf && !vc->vc_disp_ctrl) {
                    /* Combine UTF-8 into Unicode in vc_utf_char.
                     * vc_utf_count is the number of continuation bytes still
                     * expected to arrive.
                     * vc_npar is the number of continuation bytes arrived so
                     * far
                     */
rescan_last_byte:
                    if ((c & 0xc0) == 0x80) {
                        /* Continuation byte received */
                        static const uint32_t utf8_length_changes[] = { 0x0000007f, 0x000007ff, 0x0000ffff, 0x001fffff, 0x03ffffff, 0x7fffffff };
                        if (vc->vc_utf_count) {
                            vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
                            vc->vc_npar++;
                            if (--vc->vc_utf_count) {
                                /* Still need some bytes */
                                continue;
                            }
                            /* Got a whole character */
                            c = vc->vc_utf_char;
                            /* Reject overlong sequences */
                            if (c <= utf8_length_changes[vc->vc_npar - 1] ||
                                        c > utf8_length_changes[vc->vc_npar])
                                c = 0xfffd;
                        } else {
                            /* Unexpected continuation byte */
                            vc->vc_utf_count = 0;
                            c = 0xfffd;
                        }
                    } else {
                        /* Single ASCII byte or first byte of a sequence received */
                        if (vc->vc_utf_count) {
                            /* Continuation byte expected */
                            rescan = 1;
                            vc->vc_utf_count = 0;
                            c = 0xfffd;
                        } else if (c > 0x7f) {
                            /* First byte of a multibyte sequence received */
                            vc->vc_npar = 0;
                            if ((c & 0xe0) == 0xc0) {
                                vc->vc_utf_count = 1;
                                vc->vc_utf_char = (c & 0x1f);
                            } else if ((c & 0xf0) == 0xe0) {
                                vc->vc_utf_count = 2;
                                vc->vc_utf_char = (c & 0x0f);
                            } else if ((c & 0xf8) == 0xf0) {
                                vc->vc_utf_count = 3;
                                vc->vc_utf_char = (c & 0x07);
                            } else if ((c & 0xfc) == 0xf8) {
                                vc->vc_utf_count = 4;
                                vc->vc_utf_char = (c & 0x03);
                            } else if ((c & 0xfe) == 0xfc) {
                                vc->vc_utf_count = 5;
                                vc->vc_utf_char = (c & 0x01);
                            } else {
                                /* 254 and 255 are invalid */
                                c = 0xfffd;
                            }
                            if (vc->vc_utf_count) {
                                /* Still need some bytes */
                                continue;
                            }
                        }
                        /* Nothing to do if an ASCII byte was received */
                    }
                    /* End of UTF-8 decoding. */
                    /* c is the received character, or U+FFFD for invalid sequences. */
                    /* Replace invalid Unicode code points with U+FFFD too */
                    if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)
                        c = 0xfffd;
                    tc = c;
                } else {        /* no utf or alternate charset mode */
                    tc = vc_translate(vc, c);
                }

                param.c = tc;
                if (atomic_notifier_call_chain(&vt_notifier_list, VT_PREWRITE,
                                        &param) == NOTIFY_STOP)
                        continue;

                /* If the original code was a control character we
                 * only allow a glyph to be displayed if the code is
                 * not normally used (such as for cursor movement) or
                 * if the disp_ctrl mode has been explicitly enabled.
                 * Certain characters (as given by the CTRL_ALWAYS
                 * bitmap) are always displayed as control characters,
                 * as the console would be pretty useless without
                 * them; to display an arbitrary font position use the
                 * direct-to-font zone in UTF-8 mode.
                 */
                ok = tc && (c >= 32 ||
                            !(vc->vc_disp_ctrl ? (CTRL_ALWAYS >> c) & 1 :
                                  vc->vc_utf || ((CTRL_ACTION >> c) & 1)))
                        && (c != 127 || vc->vc_disp_ctrl)
                        && (c != 128+27);

                if (vc->vc_state == ESnormal && ok) {
                        if (vc->vc_utf && !vc->vc_disp_ctrl) {
                                if (is_double_width(c))
                                        width = 2;
                        }
                        /* Now try to find out how to display it */
                        tc = conv_uni_to_pc(vc, tc);
                        if (tc & ~charmask) {
                                if (tc == -1 || tc == -2) {
                                    continue; /* nothing to display */
                                }
                                /* Glyph not found */
                                if ((!(vc->vc_utf && !vc->vc_disp_ctrl) || c < 128) && !(c & ~charmask)) {
                                    /* In legacy mode use the glyph we get by a 1:1 mapping.
                                       This would make absolutely no sense with Unicode in mind,
                                       but do this for ASCII characters since a font may lack
                                       Unicode mapping info and we don't want to end up with
                                       having question marks only. */
                                    tc = c;
                                } else {
                                    /* Display U+FFFD. If it's not found, display an inverse question mark. */
                                    tc = conv_uni_to_pc(vc, 0xfffd);
                                    if (tc < 0) {
                                        inverse = 1;
                                        tc = conv_uni_to_pc(vc, '?');
                                        if (tc < 0) tc = '?';
                                    }
                                }
                        }

                        if (!inverse) {
                                vc_attr = vc->vc_attr;
                        } else {
                                /* invert vc_attr */
                                if (!vc->vc_can_do_color) {
                                        vc_attr = (vc->vc_attr) ^ 0x08;
                                } else if (vc->vc_hi_font_mask == 0x100) {
                                        vc_attr = ((vc->vc_attr) & 0x11) | (((vc->vc_attr) & 0xe0) >> 4) | (((vc->vc_attr) & 0x0e) << 4);
                                } else {
                                        vc_attr = ((vc->vc_attr) & 0x88) | (((vc->vc_attr) & 0x70) >> 4) | (((vc->vc_attr) & 0x07) << 4);
                                }
                                con_flush(vc, draw_from, draw_to, &draw_x);
                        }

                        next_c = c;
                        while (1) {
                                if (vc->vc_need_wrap || vc->vc_decim)
                                        con_flush(vc, draw_from, draw_to,
                                                        &draw_x);
                                if (vc->vc_need_wrap) {
                                        cr(vc);
                                        lf(vc);
                                }
                                if (vc->vc_decim)
                                        insert_char(vc, 1);
                                vc_uniscr_putc(vc, next_c);
                                scr_writew(himask ?
                                             ((vc_attr << 8) & ~himask) + ((tc & 0x100) ? himask : 0) + (tc & 0xff) :
                                             (vc_attr << 8) + tc,
                                           (u16 *) vc->vc_pos);
                                if (con_should_update(vc) && draw_x < 0) {
                                        draw_x = vc->vc_x;
                                        draw_from = vc->vc_pos;
                                }
                                if (vc->vc_x == vc->vc_cols - 1) {
                                        vc->vc_need_wrap = vc->vc_decawm;
                                        draw_to = vc->vc_pos + 2;
                                } else {
                                        vc->vc_x++;
                                        draw_to = (vc->vc_pos += 2);
                                }

                                if (!--width) break;

                                tc = conv_uni_to_pc(vc, ' '); /* A space is printed in the second column */
                                if (tc < 0) tc = ' ';
                                next_c = ' ';
                        }
                        notify_write(vc, c);

                        if (inverse)
                                con_flush(vc, draw_from, draw_to, &draw_x);

                        if (rescan) {
                                rescan = 0;
                                inverse = 0;
                                width = 1;
                                c = orig;
                                goto rescan_last_byte;
                        }
                        continue;
                }
                con_flush(vc, draw_from, draw_to, &draw_x);
                do_con_trol(tty, vc, orig);
        }
        con_flush(vc, draw_from, draw_to, &draw_x);
        vc_uniscr_debug_check(vc);
        console_conditional_schedule();
        console_unlock();
        notify_update(vc);
        return n;
}

/*
 * This is the console switching callback.
 *
 * Doing console switching in a process context allows
 * us to do the switches asynchronously (needed when we want
 * to switch due to a keyboard interrupt).  Synchronization
 * with other console code and prevention of re-entrancy is
 * ensured with console_lock.
 */
static void console_callback(struct work_struct *ignored)
{
        console_lock();

        if (want_console >= 0) {
                if (want_console != fg_console &&
                    vc_cons_allocated(want_console)) {
                        hide_cursor(vc_cons[fg_console].d);
                        change_console(vc_cons[want_console].d);
                        /* we only changed when the console had already
                           been allocated - a new console is not created
                           in an interrupt routine */
                }
                want_console = -1;
        }
        if (do_poke_blanked_console) { /* do not unblank for a LED change */
                do_poke_blanked_console = 0;
                poke_blanked_console();
        }
        if (scrollback_delta) {
                struct vc_data *vc = vc_cons[fg_console].d;
                clear_selection();
                if (vc->vc_mode == KD_TEXT && vc->vc_sw->con_scrolldelta)
                        vc->vc_sw->con_scrolldelta(vc, scrollback_delta);
                scrollback_delta = 0;
        }
        if (blank_timer_expired) {
                do_blank_screen(0);
                blank_timer_expired = 0;
        }
        notify_update(vc_cons[fg_console].d);

        console_unlock();
}

int set_console(int nr)
{
        struct vc_data *vc = vc_cons[fg_console].d;

        if (!vc_cons_allocated(nr) || vt_dont_switch ||
                (vc->vt_mode.mode == VT_AUTO && vc->vc_mode == KD_GRAPHICS)) {

                /*
                 * Console switch will fail in console_callback() or
                 * change_console() so there is no point scheduling
                 * the callback
                 *
                 * Existing set_console() users don't check the return
                 * value so this shouldn't break anything
                 */
                return -EINVAL;
        }

        want_console = nr;
        schedule_console_callback();

        return 0;
}

struct tty_driver *console_driver;

#ifdef CONFIG_VT_CONSOLE

/**
 * vt_kmsg_redirect() - Sets/gets the kernel message console
 * @new:        The new virtual terminal number or -1 if the console should stay
 *              unchanged
 *
 * By default, the kernel messages are always printed on the current virtual
 * console. However, the user may modify that default with the
 * TIOCL_SETKMSGREDIRECT ioctl call.
 *
 * This function sets the kernel message console to be @new. It returns the old
 * virtual console number. The virtual terminal number 0 (both as parameter and
 * return value) means no redirection (i.e. always printed on the currently
 * active console).
 *
 * The parameter -1 means that only the current console is returned, but the
 * value is not modified. You may use the macro vt_get_kmsg_redirect() in that
 * case to make the code more understandable.
 *
 * When the kernel is compiled without CONFIG_VT_CONSOLE, this function ignores
 * the parameter and always returns 0.
 */
int vt_kmsg_redirect(int new)
{
        static int kmsg_con;

        if (new != -1)
                return xchg(&kmsg_con, new);
        else
                return kmsg_con;
}

/*
 *      Console on virtual terminal
 *
 * The console must be locked when we get here.
 */

static void vt_console_print(struct console *co, const char *b, unsigned count)
{
        struct vc_data *vc = vc_cons[fg_console].d;
        unsigned char c;
        static DEFINE_SPINLOCK(printing_lock);
        const ushort *start;
        ushort cnt = 0;
        ushort myx;
        int kmsg_console;

        /* console busy or not yet initialized */
        if (!printable)
                return;
        if (!spin_trylock(&printing_lock))
                return;

        kmsg_console = vt_get_kmsg_redirect();
        if (kmsg_console && vc_cons_allocated(kmsg_console - 1))
                vc = vc_cons[kmsg_console - 1].d;

        /* read `x' only after setting currcons properly (otherwise
           the `x' macro will read the x of the foreground console). */
        myx = vc->vc_x;

        if (!vc_cons_allocated(fg_console)) {
                /* impossible */
                /* printk("vt_console_print: tty %d not allocated ??\n", currcons+1); */
                goto quit;
        }

        if (vc->vc_mode != KD_TEXT && !vt_force_oops_output(vc))
                goto quit;

        /* undraw cursor first */
        if (con_is_fg(vc))
                hide_cursor(vc);

        start = (ushort *)vc->vc_pos;

        /* Contrived structure to try to emulate original need_wrap behaviour
         * Problems caused when we have need_wrap set on '\n' character */
        while (count--) {
                c = *b++;
                if (c == 10 || c == 13 || c == 8 || vc->vc_need_wrap) {
                        if (cnt > 0) {
                                if (con_is_visible(vc))
                                        vc->vc_sw->con_putcs(vc, start, cnt, vc->vc_y, vc->vc_x);
                                vc->vc_x += cnt;
                                if (vc->vc_need_wrap)
                                        vc->vc_x--;
                                cnt = 0;
                        }
                        if (c == 8) {           /* backspace */
                                bs(vc);
                                start = (ushort *)vc->vc_pos;
                                myx = vc->vc_x;
                                continue;
                        }
                        if (c != 13)
                                lf(vc);
                        cr(vc);
                        start = (ushort *)vc->vc_pos;
                        myx = vc->vc_x;
                        if (c == 10 || c == 13)
                                continue;
                }
                scr_writew((vc->vc_attr << 8) + c, (unsigned short *)vc->vc_pos);
                notify_write(vc, c);
                cnt++;
                if (myx == vc->vc_cols - 1) {
                        vc->vc_need_wrap = 1;
                        continue;
                }
                vc->vc_pos += 2;
                myx++;
        }
        if (cnt > 0) {
                if (con_is_visible(vc))
                        vc->vc_sw->con_putcs(vc, start, cnt, vc->vc_y, vc->vc_x);
                vc->vc_x += cnt;
                if (vc->vc_x == vc->vc_cols) {
                        vc->vc_x--;
                        vc->vc_need_wrap = 1;
                }
        }
        set_cursor(vc);
        notify_update(vc);

quit:
        spin_unlock(&printing_lock);
}

static struct tty_driver *vt_console_device(struct console *c, int *index)
{
        *index = c->index ? c->index-1 : fg_console;
        return console_driver;
}

static struct console vt_console_driver = {
        .name           = "tty",
        .write          = vt_console_print,
        .device         = vt_console_device,
        .unblank        = unblank_screen,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
};
#endif

/*
 *      Handling of Linux-specific VC ioctls
 */

/*
 * Generally a bit racy with respect to console_lock();.
 *
 * There are some functions which don't need it.
 *