2 files changed, 107 insertions, 68 deletions

diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
index 2384ea85ffaf..160f46115aaa 100644
--- a/drivers/tty/vt/vc_screen.c
+++ b/drivers/tty/vt/vc_screen.c
@@ -80,7 +80,7 @@
 struct vcs_poll_data {
 	struct notifier_block notifier;
 	unsigned int cons_num;
-	bool seen_last_update;
+	int event;
 	wait_queue_head_t waitq;
 	struct fasync_struct *fasync;
 };
@@ -93,9 +93,18 @@ vcs_notifier(struct notifier_block *nb, unsigned long code, void *_param)
 	struct vcs_poll_data *poll =
 		container_of(nb, struct vcs_poll_data, notifier);
 	int currcons = poll->cons_num;
-
-	if (code != VT_UPDATE)
+	int fa_band;
+
+	switch (code) {
+	case VT_UPDATE:
+		fa_band = POLL_PRI;
+		break;
+	case VT_DEALLOCATE:
+		fa_band = POLL_HUP;
+		break;
+	default:
 		return NOTIFY_DONE;
+	}
 
 	if (currcons == 0)
 		currcons = fg_console;
@@ -104,9 +113,9 @@ vcs_notifier(struct notifier_block *nb, unsigned long code, void *_param)
 	if (currcons != vc->vc_num)
 		return NOTIFY_DONE;
 
-	poll->seen_last_update = false;
+	poll->event = code;
 	wake_up_interruptible(&poll->waitq);
-	kill_fasync(&poll->fasync, SIGIO, POLL_IN);
+	kill_fasync(&poll->fasync, SIGIO, fa_band);
 	return NOTIFY_OK;
 }
 
@@ -131,6 +140,15 @@ vcs_poll_data_get(struct file *file)
 	poll->cons_num = console(file_inode(file));
 	init_waitqueue_head(&poll->waitq);
 	poll->notifier.notifier_call = vcs_notifier;
+	/*
+	 * In order not to lose any update event, we must pretend one might
+	 * have occurred before we have a chance to register our notifier.
+	 * This is also how user space has come to detect which kernels
+	 * support POLLPRI on /dev/vcs* devices i.e. using poll() with
+	 * POLLPRI and a zero timeout.
+	 */
+	poll->event = VT_UPDATE;
+
 	if (register_vt_notifier(&poll->notifier) != 0) {
 		kfree(poll);
 		return NULL;
@@ -261,7 +279,7 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 
 	poll = file->private_data;
 	if (count && poll)
-		poll->seen_last_update = true;
+		poll->event = 0;
 	read = 0;
 	ret = 0;
 	while (count) {
@@ -335,8 +353,9 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 			if (p < HEADER_SIZE) {
 				size_t tmp_count;
 
-				con_buf0[0] = (char)vc->vc_rows;
-				con_buf0[1] = (char)vc->vc_cols;
+				/* clamp header values if they don't fit */
+				con_buf0[0] = min(vc->vc_rows, 0xFFu);
+				con_buf0[1] = min(vc->vc_cols, 0xFFu);
 				getconsxy(vc, con_buf0 + 2);
 
 				con_buf_start += p;
@@ -615,12 +634,21 @@ static __poll_t
 vcs_poll(struct file *file, poll_table *wait)
 {
 	struct vcs_poll_data *poll = vcs_poll_data_get(file);
-	__poll_t ret = DEFAULT_POLLMASK|EPOLLERR|EPOLLPRI;
+	__poll_t ret = DEFAULT_POLLMASK|EPOLLERR;
 
 	if (poll) {
 		poll_wait(file, &poll->waitq, wait);
-		if (poll->seen_last_update)
+		switch (poll->event) {
+		case VT_UPDATE:
+			ret = DEFAULT_POLLMASK|EPOLLPRI;
+			break;
+		case VT_DEALLOCATE:
+			ret = DEFAULT_POLLMASK|EPOLLHUP|EPOLLERR;
+			break;
+		case 0:
 			ret = DEFAULT_POLLMASK;
+			break;
+		}
 	}
 	return ret;
 }
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 41ec8e5010f3..d34984aa646d 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -935,8 +935,11 @@ static void flush_scrollback(struct vc_data *vc)
 {
 	WARN_CONSOLE_UNLOCKED();
 
+	set_origin(vc);
 	if (vc->vc_sw->con_flush_scrollback)
 		vc->vc_sw->con_flush_scrollback(vc);
+	else
+		vc->vc_sw->con_switch(vc);
 }
 
 /*
@@ -1272,6 +1275,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 	if (con_is_visible(vc))
 		update_screen(vc);
 	vt_event_post(VT_EVENT_RESIZE, vc->vc_num, vc->vc_num);
+	notify_update(vc);
 	return err;
 }
 
@@ -1341,6 +1345,8 @@ struct vc_data *vc_deallocate(unsigned int currcons)
  *	VT102 emulator
  */
 
+enum { EPecma = 0, EPdec, EPeq, EPgt, EPlt};
+
 #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))
@@ -1502,8 +1508,10 @@ static void csi_J(struct vc_data *vc, int vpar)
 			count = ((vc->vc_pos - vc->vc_origin) >> 1) + 1;
 			start = (unsigned short *)vc->vc_origin;
 			break;
+		case 3: /* include scrollback */
+			flush_scrollback(vc);
+			/* fallthrough */
 		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;
@@ -1512,13 +1520,7 @@ static void csi_J(struct vc_data *vc, int vpar)
 			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);
+	update_region(vc, (unsigned long) start, count);
 	vc->vc_need_wrap = 0;
 }
 
@@ -1627,9 +1629,9 @@ static void rgb_background(struct vc_data *vc, const struct rgb *c)
 
 /*
  * 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.
+ * and thus need to be detected and ignored by hand. That standard also
+ * wants : rather than ; as separators but sequences containing : are currently
+ * completely ignored by the parser.
  *
  * Subcommands 3 (CMY) and 4 (CMYK) are so insane there's no point in
  * supporting them.
@@ -1814,7 +1816,7 @@ 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) {
+		if (vc->vc_priv == EPdec) {
 			switch(vc->vc_par[i]) {	/* DEC private modes set/reset */
 			case 1:			/* Cursor keys send ^[Ox/^[[x */
 				if (on_off)
@@ -2021,7 +2023,7 @@ static void restore_cur(struct vc_data *vc)
 }
 
 enum { ESnormal, ESesc, ESsquare, ESgetpars, ESfunckey,
-	EShash, ESsetG0, ESsetG1, ESpercent, ESignore, ESnonstd,
+	EShash, ESsetG0, ESsetG1, ESpercent, EScsiignore, ESnonstd,
 	ESpalette, ESosc };
 
 /* console_lock is held (except via vc_init()) */
@@ -2030,7 +2032,7 @@ 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_priv		= EPecma;
 	vc->vc_translate	= set_translate(LAT1_MAP, vc);
 	vc->vc_G0_charset	= LAT1_MAP;
 	vc->vc_G1_charset	= GRAF_MAP;
@@ -2111,6 +2113,7 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 		lf(vc);
 		if (!is_kbd(vc, lnm))
 			return;
+		/* fall through */
 	case 13:
 		cr(vc);
 		return;
@@ -2233,9 +2236,22 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 			vc->vc_state=ESfunckey;
 			return;
 		}
-		vc->vc_ques = (c == '?');
-		if (vc->vc_ques)
+		switch (c) {
+		case '?':
+			vc->vc_priv = EPdec;
 			return;
+		case '>':
+			vc->vc_priv = EPgt;
+			return;
+		case '=':
+			vc->vc_priv = EPeq;
+			return;
+		case '<':
+			vc->vc_priv = EPlt;
+			return;
+		}
+		vc->vc_priv = EPecma;
+		/* fall through */
 	case ESgetpars:
 		if (c == ';' && vc->vc_npar < NPAR - 1) {
 			vc->vc_npar++;
@@ -2245,16 +2261,22 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 			vc->vc_par[vc->vc_npar] += c - '0';
 			return;
 		}
+		if (c >= 0x20 && c <= 0x3f) { /* 0x2x, 0x3a and 0x3c - 0x3f */
+			vc->vc_state = EScsiignore;
+			return;
+		}
 		vc->vc_state = ESnormal;
 		switch(c) {
 		case 'h':
-			set_mode(vc, 1);
+			if (vc->vc_priv <= EPdec)
+				set_mode(vc, 1);
 			return;
 		case 'l':
-			set_mode(vc, 0);
+			if (vc->vc_priv <= EPdec)
+				set_mode(vc, 0);
 			return;
 		case 'c':
-			if (vc->vc_ques) {
+			if (vc->vc_priv == EPdec) {
 				if (vc->vc_par[0])
 					vc->vc_cursor_type = vc->vc_par[0] | (vc->vc_par[1] << 8) | (vc->vc_par[2] << 16);
 				else
@@ -2263,7 +2285,7 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 			}
 			break;
 		case 'm':
-			if (vc->vc_ques) {
+			if (vc->vc_priv == EPdec) {
 				clear_selection();
 				if (vc->vc_par[0])
 					vc->vc_complement_mask = vc->vc_par[0] << 8 | vc->vc_par[1];
@@ -2273,7 +2295,7 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 			}
 			break;
 		case 'n':
-			if (!vc->vc_ques) {
+			if (vc->vc_priv == EPecma) {
 				if (vc->vc_par[0] == 5)
 					status_report(tty);
 				else if (vc->vc_par[0] == 6)
@@ -2281,8 +2303,8 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 			}
 			return;
 		}
-		if (vc->vc_ques) {
-			vc->vc_ques = 0;
+		if (vc->vc_priv != EPecma) {
+			vc->vc_priv = EPecma;
 			return;
 		}
 		switch(c) {
@@ -2405,6 +2427,11 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 			return;
 		}
 		return;
+	case EScsiignore:
+		if (c >= 20 && c <= 0x3f)
+			return;
+		vc->vc_state = ESnormal;
+		return;
 	case ESpercent:
 		vc->vc_state = ESnormal;
 		switch (c) {
@@ -2764,8 +2791,8 @@ rescan_last_byte:
 	con_flush(vc, draw_from, draw_to, &draw_x);
 	vc_uniscr_debug_check(vc);
 	console_conditional_schedule();
-	console_unlock();
 	notify_update(vc);
+	console_unlock();
 	return n;
 }
 
@@ -2884,8 +2911,7 @@ static void vt_console_print(struct console *co, const char *b, unsigned count)
 	unsigned char c;
 	static DEFINE_SPINLOCK(printing_lock);
 	const ushort *start;
-	ushort cnt = 0;
-	ushort myx;
+	ushort start_x, cnt;
 	int kmsg_console;
 
 	/* console busy or not yet initialized */
@@ -2898,10 +2924,6 @@ static void vt_console_print(struct console *co, const char *b, unsigned count)
 	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); */
@@ -2916,53 +2938,41 @@ static void vt_console_print(struct console *co, const char *b, unsigned count)
 		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 */
+	start_x = vc->vc_x;
+	cnt = 0;
 	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 (cnt && con_is_visible(vc))
+				vc->vc_sw->con_putcs(vc, start, cnt, vc->vc_y, start_x);
+			cnt = 0;
 			if (c == 8) {		/* backspace */
 				bs(vc);
 				start = (ushort *)vc->vc_pos;
-				myx = vc->vc_x;
+				start_x = vc->vc_x;
 				continue;
 			}
 			if (c != 13)
 				lf(vc);
 			cr(vc);
 			start = (ushort *)vc->vc_pos;
-			myx = vc->vc_x;
+			start_x = vc->vc_x;
 			if (c == 10 || c == 13)
 				continue;
 		}
+		vc_uniscr_putc(vc, c);
 		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--;
+		if (vc->vc_x == vc->vc_cols - 1) {
 			vc->vc_need_wrap = 1;
+		} else {
+			vc->vc_pos += 2;
+			vc->vc_x++;
 		}
 	}
+	if (cnt && con_is_visible(vc))
+		vc->vc_sw->con_putcs(vc, start, cnt, vc->vc_y, start_x);
 	set_cursor(vc);
 	notify_update(vc);
 
@@ -4607,8 +4617,9 @@ EXPORT_SYMBOL_GPL(screen_pos);
 
 void getconsxy(struct vc_data *vc, unsigned char *p)
 {
-	p[0] = vc->vc_x;
-	p[1] = vc->vc_y;
+	/* clamp values if they don't fit */
+	p[0] = min(vc->vc_x, 0xFFu);
+	p[1] = min(vc->vc_y, 0xFFu);
 }
 
 void putconsxy(struct vc_data *vc, unsigned char *p)