3 files changed, 179 insertions, 87 deletions

diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index c3f1fb9ee820..5b71bd905a60 100644
--- a/drivers/video/console/Kconfig
+++ b/drivers/video/console/Kconfig
@@ -43,9 +43,30 @@ config VGACON_SOFT_SCROLLBACK_SIZE
        range 1 1024
        default "64"
        help
-         Enter the amount of System RAM to allocate for the scrollback
-	 buffer.  Each 64KB will give you approximately 16 80x25
-	 screenfuls of scrollback buffer
+	  Enter the amount of System RAM to allocate for scrollback
+	  buffers of VGA consoles. Each 64KB will give you approximately
+	  16 80x25 screenfuls of scrollback buffer.
+
+config VGACON_SOFT_SCROLLBACK_PERSISTENT_ENABLE_BY_DEFAULT
+	bool "Persistent Scrollback History for each console by default"
+	depends on VGACON_SOFT_SCROLLBACK
+	default n
+	help
+	  Say Y here if the scrollback history should persist by default when
+	  switching between consoles. Otherwise, the scrollback history will be
+	  flushed each time the console is switched. This feature can also be
+	  enabled using the boot command line parameter
+	  'vgacon.scrollback_persistent=1'.
+
+	  This feature might break your tool of choice to flush the scrollback
+	  buffer, e.g. clear(1) will work fine but Debian's clear_console(1)
+	  will be broken, which might cause security issues.
+	  You can use the escape sequence \e[3J instead if this feature is
+	  activated.
+
+	  Note that a buffer of VGACON_SOFT_SCROLLBACK_SIZE is taken for each
+	  created tty device.
+	  So if you use a RAM-constrained system, say N here.
 
 config MDA_CONSOLE
 	depends on !M68K && !PARISC && ISA
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index a44f5627b82a..12ded23f1aaf 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -412,11 +412,9 @@ static void fbcon_add_cursor_timer(struct fb_info *info)
 		if (!info->queue.func)
 			INIT_WORK(&info->queue, fb_flashcursor);
 
-		init_timer(&ops->cursor_timer);
-		ops->cursor_timer.function = cursor_timer_handler;
-		ops->cursor_timer.expires = jiffies + ops->cur_blink_jiffies;
-		ops->cursor_timer.data = (unsigned long ) info;
-		add_timer(&ops->cursor_timer);
+		setup_timer(&ops->cursor_timer, cursor_timer_handler,
+			    (unsigned long) info);
+		mod_timer(&ops->cursor_timer, jiffies + ops->cur_blink_jiffies);
 		ops->flags |= FBCON_FLAGS_CURSOR_TIMER;
 	}
 }
@@ -1165,6 +1163,8 @@ static void fbcon_free_font(struct display *p, bool freefont)
 	p->userfont = 0;
 }
 
+static void set_vc_hi_font(struct vc_data *vc, bool set);
+
 static void fbcon_deinit(struct vc_data *vc)
 {
 	struct display *p = &fb_display[vc->vc_num];
@@ -1200,6 +1200,9 @@ finished:
 	if (free_font)
 		vc->vc_font.data = NULL;
 
+	if (vc->vc_hi_font_mask)
+		set_vc_hi_font(vc, false);
+
 	if (!con_is_bound(&fb_con))
 		fbcon_exit();
 
@@ -2436,32 +2439,10 @@ static int fbcon_get_font(struct vc_data *vc, struct console_font *font)
 	return 0;
 }
 
-static int fbcon_do_set_font(struct vc_data *vc, int w, int h,
-			     const u8 * data, int userfont)
+/* set/clear vc_hi_font_mask and update vc attrs accordingly */
+static void set_vc_hi_font(struct vc_data *vc, bool set)
 {
-	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
-	struct fbcon_ops *ops = info->fbcon_par;
-	struct display *p = &fb_display[vc->vc_num];
-	int resize;
-	int cnt;
-	char *old_data = NULL;
-
-	if (con_is_visible(vc) && softback_lines)
-		fbcon_set_origin(vc);
-
-	resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
-	if (p->userfont)
-		old_data = vc->vc_font.data;
-	if (userfont)
-		cnt = FNTCHARCNT(data);
-	else
-		cnt = 256;
-	vc->vc_font.data = (void *)(p->fontdata = data);
-	if ((p->userfont = userfont))
-		REFCOUNT(data)++;
-	vc->vc_font.width = w;
-	vc->vc_font.height = h;
-	if (vc->vc_hi_font_mask && cnt == 256) {
+	if (!set) {
 		vc->vc_hi_font_mask = 0;
 		if (vc->vc_can_do_color) {
 			vc->vc_complement_mask >>= 1;
@@ -2484,7 +2465,7 @@ static int fbcon_do_set_font(struct vc_data *vc, int w, int h,
 			    ((c & 0xfe00) >> 1) | (c & 0xff);
 			vc->vc_attr >>= 1;
 		}
-	} else if (!vc->vc_hi_font_mask && cnt == 512) {
+	} else {
 		vc->vc_hi_font_mask = 0x100;
 		if (vc->vc_can_do_color) {
 			vc->vc_complement_mask <<= 1;
@@ -2516,8 +2497,38 @@ static int fbcon_do_set_font(struct vc_data *vc, int w, int h,
 			} else
 				vc->vc_video_erase_char = c & ~0x100;
 		}
-
 	}
+}
+
+static int fbcon_do_set_font(struct vc_data *vc, int w, int h,
+			     const u8 * data, int userfont)
+{
+	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
+	struct fbcon_ops *ops = info->fbcon_par;
+	struct display *p = &fb_display[vc->vc_num];
+	int resize;
+	int cnt;
+	char *old_data = NULL;
+
+	if (con_is_visible(vc) && softback_lines)
+		fbcon_set_origin(vc);
+
+	resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
+	if (p->userfont)
+		old_data = vc->vc_font.data;
+	if (userfont)
+		cnt = FNTCHARCNT(data);
+	else
+		cnt = 256;
+	vc->vc_font.data = (void *)(p->fontdata = data);
+	if ((p->userfont = userfont))
+		REFCOUNT(data)++;
+	vc->vc_font.width = w;
+	vc->vc_font.height = h;
+	if (vc->vc_hi_font_mask && cnt == 256)
+		set_vc_hi_font(vc, false);
+	else if (!vc->vc_hi_font_mask && cnt == 512)
+		set_vc_hi_font(vc, true);
 
 	if (resize) {
 		int cols, rows;
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index c22a56232b7c..dc06cb6a15dc 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -162,70 +162,118 @@ static inline void vga_set_mem_top(struct vc_data *c)
 
 #ifdef CONFIG_VGACON_SOFT_SCROLLBACK
 /* software scrollback */
-static void *vgacon_scrollback;
-static int vgacon_scrollback_tail;
-static int vgacon_scrollback_size;
-static int vgacon_scrollback_rows;
-static int vgacon_scrollback_cnt;
-static int vgacon_scrollback_cur;
-static int vgacon_scrollback_save;
-static int vgacon_scrollback_restore;
-
-static void vgacon_scrollback_init(int pitch)
+struct vgacon_scrollback_info {
+	void *data;
+	int tail;
+	int size;
+	int rows;
+	int cnt;
+	int cur;
+	int save;
+	int restore;
+};
+
+static struct vgacon_scrollback_info *vgacon_scrollback_cur;
+static struct vgacon_scrollback_info vgacon_scrollbacks[MAX_NR_CONSOLES];
+static bool scrollback_persistent = \
+	IS_ENABLED(CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT_ENABLE_BY_DEFAULT);
+module_param_named(scrollback_persistent, scrollback_persistent, bool, 0000);
+MODULE_PARM_DESC(scrollback_persistent, "Enable persistent scrollback for all vga consoles");
+
+static void vgacon_scrollback_reset(int vc_num, size_t reset_size)
+{
+	struct vgacon_scrollback_info *scrollback = &vgacon_scrollbacks[vc_num];
+
+	if (scrollback->data && reset_size > 0)
+		memset(scrollback->data, 0, reset_size);
+
+	scrollback->cnt  = 0;
+	scrollback->tail = 0;
+	scrollback->cur  = 0;
+}
+
+static void vgacon_scrollback_init(int vc_num)
+{
+	int pitch = vga_video_num_columns * 2;
+	size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024;
+	int rows = size / pitch;
+	void *data;
+
+	data = kmalloc_array(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE, 1024,
+			     GFP_NOWAIT);
+
+	vgacon_scrollbacks[vc_num].data = data;
+	vgacon_scrollback_cur = &vgacon_scrollbacks[vc_num];
+
+	vgacon_scrollback_cur->rows = rows - 1;
+	vgacon_scrollback_cur->size = rows * pitch;
+
+	vgacon_scrollback_reset(vc_num, size);
+}
+
+static void vgacon_scrollback_switch(int vc_num)
 {
-	int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;
-
-	if (vgacon_scrollback) {
-		vgacon_scrollback_cnt  = 0;
-		vgacon_scrollback_tail = 0;
-		vgacon_scrollback_cur  = 0;
-		vgacon_scrollback_rows = rows - 1;
-		vgacon_scrollback_size = rows * pitch;
+	if (!scrollback_persistent)
+		vc_num = 0;
+
+	if (!vgacon_scrollbacks[vc_num].data) {
+		vgacon_scrollback_init(vc_num);
+	} else {
+		if (scrollback_persistent) {
+			vgacon_scrollback_cur = &vgacon_scrollbacks[vc_num];
+		} else {
+			size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024;
+
+			vgacon_scrollback_reset(vc_num, size);
+		}
 	}
 }
 
 static void vgacon_scrollback_startup(void)
 {
-	vgacon_scrollback = kcalloc(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE, 1024, GFP_NOWAIT);
-	vgacon_scrollback_init(vga_video_num_columns * 2);
+	vgacon_scrollback_cur = &vgacon_scrollbacks[0];
+	vgacon_scrollback_init(0);
 }
 
 static void vgacon_scrollback_update(struct vc_data *c, int t, int count)
 {
 	void *p;
 
-	if (!vgacon_scrollback_size || c->vc_num != fg_console)
+	if (!vgacon_scrollback_cur->data || !vgacon_scrollback_cur->size ||
+	    c->vc_num != fg_console)
 		return;
 
 	p = (void *) (c->vc_origin + t * c->vc_size_row);
 
 	while (count--) {
-		scr_memcpyw(vgacon_scrollback + vgacon_scrollback_tail,
+		scr_memcpyw(vgacon_scrollback_cur->data +
+			    vgacon_scrollback_cur->tail,
 			    p, c->vc_size_row);
-		vgacon_scrollback_cnt++;
+
+		vgacon_scrollback_cur->cnt++;
 		p += c->vc_size_row;
-		vgacon_scrollback_tail += c->vc_size_row;
+		vgacon_scrollback_cur->tail += c->vc_size_row;
 
-		if (vgacon_scrollback_tail >= vgacon_scrollback_size)
-			vgacon_scrollback_tail = 0;
+		if (vgacon_scrollback_cur->tail >= vgacon_scrollback_cur->size)
+			vgacon_scrollback_cur->tail = 0;
 
-		if (vgacon_scrollback_cnt > vgacon_scrollback_rows)
-			vgacon_scrollback_cnt = vgacon_scrollback_rows;
+		if (vgacon_scrollback_cur->cnt > vgacon_scrollback_cur->rows)
+			vgacon_scrollback_cur->cnt = vgacon_scrollback_cur->rows;
 
-		vgacon_scrollback_cur = vgacon_scrollback_cnt;
+		vgacon_scrollback_cur->cur = vgacon_scrollback_cur->cnt;
 	}
 }
 
 static void vgacon_restore_screen(struct vc_data *c)
 {
-	vgacon_scrollback_save = 0;
+	vgacon_scrollback_cur->save = 0;
 
-	if (!vga_is_gfx && !vgacon_scrollback_restore) {
+	if (!vga_is_gfx && !vgacon_scrollback_cur->restore) {
 		scr_memcpyw((u16 *) c->vc_origin, (u16 *) c->vc_screenbuf,
 			    c->vc_screenbuf_size > vga_vram_size ?
 			    vga_vram_size : c->vc_screenbuf_size);
-		vgacon_scrollback_restore = 1;
-		vgacon_scrollback_cur = vgacon_scrollback_cnt;
+		vgacon_scrollback_cur->restore = 1;
+		vgacon_scrollback_cur->cur = vgacon_scrollback_cur->cnt;
 	}
 }
 
@@ -239,41 +287,41 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines)
 		return;
 	}
 
-	if (!vgacon_scrollback)
+	if (!vgacon_scrollback_cur->data)
 		return;
 
-	if (!vgacon_scrollback_save) {
+	if (!vgacon_scrollback_cur->save) {
 		vgacon_cursor(c, CM_ERASE);
 		vgacon_save_screen(c);
-		vgacon_scrollback_save = 1;
+		vgacon_scrollback_cur->save = 1;
 	}
 
-	vgacon_scrollback_restore = 0;
-	start = vgacon_scrollback_cur + lines;
+	vgacon_scrollback_cur->restore = 0;
+	start = vgacon_scrollback_cur->cur + lines;
 	end = start + abs(lines);
 
 	if (start < 0)
 		start = 0;
 
-	if (start > vgacon_scrollback_cnt)
-		start = vgacon_scrollback_cnt;
+	if (start > vgacon_scrollback_cur->cnt)
+		start = vgacon_scrollback_cur->cnt;
 
 	if (end < 0)
 		end = 0;
 
-	if (end > vgacon_scrollback_cnt)
-		end = vgacon_scrollback_cnt;
+	if (end > vgacon_scrollback_cur->cnt)
+		end = vgacon_scrollback_cur->cnt;
 
-	vgacon_scrollback_cur = start;
+	vgacon_scrollback_cur->cur = start;
 	count = end - start;
-	soff = vgacon_scrollback_tail - ((vgacon_scrollback_cnt - end) *
-					 c->vc_size_row);
+	soff = vgacon_scrollback_cur->tail -
+		((vgacon_scrollback_cur->cnt - end) * c->vc_size_row);
 	soff -= count * c->vc_size_row;
 
 	if (soff < 0)
-		soff += vgacon_scrollback_size;
+		soff += vgacon_scrollback_cur->size;
 
-	count = vgacon_scrollback_cnt - start;
+	count = vgacon_scrollback_cur->cnt - start;
 
 	if (count > c->vc_rows)
 		count = c->vc_rows;
@@ -287,13 +335,13 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines)
 
 		count *= c->vc_size_row;
 		/* how much memory to end of buffer left? */
-		copysize = min(count, vgacon_scrollback_size - soff);
-		scr_memcpyw(d, vgacon_scrollback + soff, copysize);
+		copysize = min(count, vgacon_scrollback_cur->size - soff);
+		scr_memcpyw(d, vgacon_scrollback_cur->data + soff, copysize);
 		d += copysize;
 		count -= copysize;
 
 		if (count) {
-			scr_memcpyw(d, vgacon_scrollback, count);
+			scr_memcpyw(d, vgacon_scrollback_cur->data, count);
 			d += count;
 		}
 
@@ -302,10 +350,18 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines)
 	} else
 		vgacon_cursor(c, CM_MOVE);
 }
+
+static void vgacon_flush_scrollback(struct vc_data *c)
+{
+	size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024;
+
+	vgacon_scrollback_reset(c->vc_num, size);
+}
 #else
 #define vgacon_scrollback_startup(...) do { } while (0)
 #define vgacon_scrollback_init(...)    do { } while (0)
 #define vgacon_scrollback_update(...)  do { } while (0)
+#define vgacon_scrollback_switch(...)  do { } while (0)
 
 static void vgacon_restore_screen(struct vc_data *c)
 {
@@ -319,6 +375,10 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines)
 			vga_vram_size);
 	vga_set_mem_top(c);
 }
+
+static void vgacon_flush_scrollback(struct vc_data *c)
+{
+}
 #endif /* CONFIG_VGACON_SOFT_SCROLLBACK */
 
 static const char *vgacon_startup(void)
@@ -780,7 +840,7 @@ static int vgacon_switch(struct vc_data *c)
 			vgacon_doresize(c, c->vc_cols, c->vc_rows);
 	}
 
-	vgacon_scrollback_init(c->vc_size_row);
+	vgacon_scrollback_switch(c->vc_num);
 	return 0;		/* Redrawing not needed */
 }
 
@@ -1326,7 +1386,6 @@ static bool vgacon_scroll(struct vc_data *c, unsigned int t, unsigned int b,
 	return true;
 }
 
-
 /*
  *  The console `switch' structure for the VGA based console
  */
@@ -1359,6 +1418,7 @@ const struct consw vga_con = {
 	.con_save_screen = vgacon_save_screen,
 	.con_build_attr = vgacon_build_attr,
 	.con_invert_region = vgacon_invert_region,
+	.con_flush_scrollback = vgacon_flush_scrollback,
 };
 EXPORT_SYMBOL(vga_con);