From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001
From: Ali Ahmet Memis <ali@iusegentoo.com>
Date: Fri, 21 Aug 2026 01:45:27 +0000
Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>
---
 drivers/video/console/vgacon.c | 1226 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 1226 insertions(+)
 create mode 100644 drivers/video/console/vgacon.c

(limited to 'drivers/video/console/vgacon.c')

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
new file mode 100644
index 000000000..37bd18730
--- /dev/null
+++ b/drivers/video/console/vgacon.c
@@ -0,0 +1,1226 @@
+/*
+ *  linux/drivers/video/vgacon.c -- Low level VGA based console driver
+ *
+ *	Created 28 Sep 1997 by Geert Uytterhoeven
+ *
+ *	Rewritten by Martin Mares <mj@ucw.cz>, July 1998
+ *
+ *  This file is based on the old console.c, vga.c and vesa_blank.c drivers.
+ *
+ *	Copyright (C) 1991, 1992  Linus Torvalds
+ *			    1995  Jay Estabrook
+ *
+ *	User definable mapping table and font loading by Eugene G. Crosser,
+ *	<crosser@average.org>
+ *
+ *	Improved loadable font/UTF-8 support by H. Peter Anvin
+ *	Feb-Sep 1995 <peter.anvin@linux.org>
+ *
+ *	Colour palette handling, by Simon Tatham
+ *	17-Jun-95 <sgt20@cam.ac.uk>
+ *
+ *	if 512 char mode is already enabled don't re-enable it,
+ *	because it causes screen to flicker, by Mitja Horvat
+ *	5-May-96 <mitja.horvat@guest.arnes.si>
+ *
+ *	Use 2 outw instead of 4 outb_p to reduce erroneous text
+ *	flashing on RHS of screen during heavy console scrolling .
+ *	Oct 1996, Paul Gortmaker.
+ *
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License.  See the file COPYING in the main directory of this archive for
+ *  more details.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/console.h>
+#include <linux/string.h>
+#include <linux/kd.h>
+#include <linux/slab.h>
+#include <linux/vt_kern.h>
+#include <linux/sched.h>
+#include <linux/selection.h>
+#include <linux/spinlock.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/screen_info.h>
+#include <video/vga.h>
+#include <asm/io.h>
+
+static DEFINE_RAW_SPINLOCK(vga_lock);
+static int cursor_size_lastfrom;
+static int cursor_size_lastto;
+static u32 vgacon_xres;
+static u32 vgacon_yres;
+static struct vgastate vgastate;
+
+#define BLANK 0x0020
+
+#define VGA_FONTWIDTH       8   /* VGA does not support fontwidths != 8 */
+/*
+ *  Interface used by the world
+ */
+
+static bool vgacon_set_origin(struct vc_data *c);
+
+static struct uni_pagedict *vgacon_uni_pagedir;
+static int vgacon_refcount;
+
+/* Description of the hardware situation */
+static unsigned long	vga_vram_base		__read_mostly;	/* Base of video memory */
+static unsigned long	vga_vram_end		__read_mostly;	/* End of video memory */
+static unsigned int	vga_vram_size		__read_mostly;	/* Size of video memory */
+static u16		vga_video_port_reg	__read_mostly;	/* Video register select port */
+static u16		vga_video_port_val	__read_mostly;	/* Video register value port */
+static unsigned int	vga_video_num_columns;			/* Number of text columns */
+static unsigned int	vga_video_num_lines;			/* Number of text lines */
+static bool		vga_can_do_color;			/* Do we support colors? */
+static unsigned int	vga_default_font_height __read_mostly;	/* Height of default screen font */
+static unsigned char	vga_video_type		__read_mostly;	/* Card type */
+static enum vesa_blank_mode vga_vesa_blanked;
+static bool 		vga_palette_blanked;
+static bool 		vga_is_gfx;
+static bool 		vga_512_chars;
+static int 		vga_video_font_height;
+static int 		vga_scan_lines		__read_mostly;
+static unsigned int 	vga_rolled_over; /* last vc_origin offset before wrap */
+
+static struct screen_info *vga_si;
+
+static bool vga_hardscroll_enabled;
+static bool vga_hardscroll_user_enable = true;
+
+static int __init no_scroll(char *str)
+{
+	/*
+	 * Disabling scrollback is required for the Braillex ib80-piezo
+	 * Braille reader made by F.H. Papenmeier (Germany).
+	 * Use the "no-scroll" bootflag.
+	 */
+	vga_hardscroll_user_enable = vga_hardscroll_enabled = false;
+	return 1;
+}
+
+__setup("no-scroll", no_scroll);
+
+/*
+ * By replacing the four outb_p with two back to back outw, we can reduce
+ * the window of opportunity to see text mislocated to the RHS of the
+ * console during heavy scrolling activity. However there is the remote
+ * possibility that some pre-dinosaur hardware won't like the back to back
+ * I/O. Since the Xservers get away with it, we should be able to as well.
+ */
+static inline void write_vga(unsigned char reg, unsigned int val)
+{
+	unsigned int v1, v2;
+	unsigned long flags;
+
+	/*
+	 * ddprintk might set the console position from interrupt
+	 * handlers, thus the write has to be IRQ-atomic.
+	 */
+	raw_spin_lock_irqsave(&vga_lock, flags);
+	v1 = reg + (val & 0xff00);
+	v2 = reg + 1 + ((val << 8) & 0xff00);
+	outw(v1, vga_video_port_reg);
+	outw(v2, vga_video_port_reg);
+	raw_spin_unlock_irqrestore(&vga_lock, flags);
+}
+
+static inline void vga_set_mem_top(struct vc_data *c)
+{
+	write_vga(12, (c->vc_visible_origin - vga_vram_base) / 2);
+}
+
+static void vgacon_scrolldelta(struct vc_data *c, int lines)
+{
+	unsigned long scr_end = c->vc_scr_end - vga_vram_base;
+	unsigned long vorigin = c->vc_visible_origin - vga_vram_base;
+	unsigned long origin = c->vc_origin - vga_vram_base;
+	int margin = c->vc_size_row * 4;
+	int from, wrap, from_off, avail;
+
+	/* Turn scrollback off */
+	if (!lines) {
+		c->vc_visible_origin = c->vc_origin;
+		return;
+	}
+
+	/* Do we have already enough to allow jumping from 0 to the end? */
+	if (vga_rolled_over > scr_end + margin) {
+		from = scr_end;
+		wrap = vga_rolled_over + c->vc_size_row;
+	} else {
+		from = 0;
+		wrap = vga_vram_size;
+	}
+
+	from_off = (vorigin - from + wrap) % wrap + lines * c->vc_size_row;
+	avail = (origin - from + wrap) % wrap;
+
+	/* Only a little piece would be left? Show all incl. the piece! */
+	if (avail < 2 * margin)
+		margin = 0;
+	if (from_off < margin)
+		from_off = 0;
+	if (from_off > avail - margin)
+		from_off = avail;
+
+	c->vc_visible_origin = vga_vram_base + (from + from_off) % wrap;
+
+	vga_set_mem_top(c);
+}
+
+static void vgacon_restore_screen(struct vc_data *c)
+{
+	if (c->vc_origin != c->vc_visible_origin)
+		vgacon_scrolldelta(c, 0);
+}
+
+static const char *vgacon_startup(void)
+{
+	const char *display_desc = NULL;
+	u16 saved1, saved2;
+	volatile u16 *p;
+
+	if (!vga_si ||
+	    vga_si->orig_video_isVGA == VIDEO_TYPE_VLFB ||
+	    vga_si->orig_video_isVGA == VIDEO_TYPE_EFI) {
+	      no_vga:
+#ifdef CONFIG_DUMMY_CONSOLE
+		conswitchp = &dummy_con;
+		return conswitchp->con_startup();
+#else
+		return NULL;
+#endif
+	}
+
+	/* vga_si reasonably initialized? */
+	if ((vga_si->orig_video_lines == 0) ||
+	    (vga_si->orig_video_cols  == 0))
+		goto no_vga;
+
+	/* VGA16 modes are not handled by VGACON */
+	if ((vga_si->orig_video_mode == 0x0D) ||	/* 320x200/4 */
+	    (vga_si->orig_video_mode == 0x0E) ||	/* 640x200/4 */
+	    (vga_si->orig_video_mode == 0x10) ||	/* 640x350/4 */
+	    (vga_si->orig_video_mode == 0x12) ||	/* 640x480/4 */
+	    (vga_si->orig_video_mode == 0x6A))	/* 800x600/4 (VESA) */
+		goto no_vga;
+
+	vga_video_num_lines = vga_si->orig_video_lines;
+	vga_video_num_columns = vga_si->orig_video_cols;
+	vgastate.vgabase = NULL;
+
+	if (vga_si->orig_video_mode == 7) {
+		/* Monochrome display */
+		vga_vram_base = 0xb0000;
+		vga_video_port_reg = VGA_CRT_IM;
+		vga_video_port_val = VGA_CRT_DM;
+		if ((vga_si->orig_video_ega_bx & 0xff) != 0x10) {
+			static struct resource ega_console_resource =
+			    { .name	= "ega",
+			      .flags	= IORESOURCE_IO,
+			      .start	= 0x3B0,
+			      .end	= 0x3BF };
+			vga_video_type = VIDEO_TYPE_EGAM;
+			vga_vram_size = 0x8000;
+			display_desc = "EGA+";
+			request_resource(&ioport_resource,
+					 &ega_console_resource);
+		} else {
+			static struct resource mda1_console_resource =
+			    { .name	= "mda",
+			      .flags	= IORESOURCE_IO,
+			      .start	= 0x3B0,
+			      .end	= 0x3BB };
+			static struct resource mda2_console_resource =
+			    { .name	= "mda",
+			      .flags	= IORESOURCE_IO,
+			      .start	= 0x3BF,
+			      .end	= 0x3BF };
+			vga_video_type = VIDEO_TYPE_MDA;
+			vga_vram_size = 0x2000;
+			display_desc = "*MDA";
+			request_resource(&ioport_resource,
+					 &mda1_console_resource);
+			request_resource(&ioport_resource,
+					 &mda2_console_resource);
+			vga_video_font_height = 14;
+		}
+	} else {
+		/* If not, it is color. */
+		vga_can_do_color = true;
+		vga_vram_base = 0xb8000;
+		vga_video_port_reg = VGA_CRT_IC;
+		vga_video_port_val = VGA_CRT_DC;
+		if ((vga_si->orig_video_ega_bx & 0xff) != 0x10) {
+			int i;
+
+			vga_vram_size = 0x8000;
+
+			if (!vga_si->orig_video_isVGA) {
+				static struct resource ega_console_resource =
+				    { .name	= "ega",
+				      .flags	= IORESOURCE_IO,
+				      .start	= 0x3C0,
+				      .end	= 0x3DF };
+				vga_video_type = VIDEO_TYPE_EGAC;
+				display_desc = "EGA";
+				request_resource(&ioport_resource,
+						 &ega_console_resource);
+			} else {
+				static struct resource vga_console_resource =
+				    { .name	= "vga+",
+				      .flags	= IORESOURCE_IO,
+				      .start	= 0x3C0,
+				      .end	= 0x3DF };
+				vga_video_type = VIDEO_TYPE_VGAC;
+				display_desc = "VGA+";
+				request_resource(&ioport_resource,
+						 &vga_console_resource);
+
+				/*
+				 * Normalise the palette registers, to point
+				 * the 16 screen colours to the first 16
+				 * DAC entries.
+				 */
+
+				for (i = 0; i < 16; i++) {
+					inb_p(VGA_IS1_RC);
+					outb_p(i, VGA_ATT_W);
+					outb_p(i, VGA_ATT_W);
+				}
+				outb_p(0x20, VGA_ATT_W);
+
+				/*
+				 * Now set the DAC registers back to their
+				 * default values
+				 */
+				for (i = 0; i < 16; i++) {
+					outb_p(color_table[i], VGA_PEL_IW);
+					outb_p(default_red[i], VGA_PEL_D);
+					outb_p(default_grn[i], VGA_PEL_D);
+					outb_p(default_blu[i], VGA_PEL_D);
+				}
+			}
+		} else {
+			static struct resource cga_console_resource =
+			    { .name	= "cga",
+			      .flags	= IORESOURCE_IO,
+			      .start	= 0x3D4,
+			      .end	= 0x3D5 };
+			vga_video_type = VIDEO_TYPE_CGA;
+			vga_vram_size = 0x2000;
+			display_desc = "*CGA";
+			request_resource(&ioport_resource,
+					 &cga_console_resource);
+			vga_video_font_height = 8;
+		}
+	}
+
+	vga_vram_base = VGA_MAP_MEM(vga_vram_base, vga_vram_size);
+	vga_vram_end = vga_vram_base + vga_vram_size;
+
+	/*
+	 *      Find out if there is a graphics card present.
+	 *      Are there smarter methods around?
+	 */
+	p = (volatile u16 *) vga_vram_base;
+	saved1 = scr_readw(p);
+	saved2 = scr_readw(p + 1);
+	scr_writew(0xAA55, p);
+	scr_writew(0x55AA, p + 1);
+	if (scr_readw(p) != 0xAA55 || scr_readw(p + 1) != 0x55AA) {
+		scr_writew(saved1, p);
+		scr_writew(saved2, p + 1);
+		goto no_vga;
+	}
+	scr_writew(0x55AA, p);
+	scr_writew(0xAA55, p + 1);
+	if (scr_readw(p) != 0x55AA || scr_readw(p + 1) != 0xAA55) {
+		scr_writew(saved1, p);
+		scr_writew(saved2, p + 1);
+		goto no_vga;
+	}
+	scr_writew(saved1, p);
+	scr_writew(saved2, p + 1);
+
+	if (vga_video_type == VIDEO_TYPE_EGAC
+	    || vga_video_type == VIDEO_TYPE_VGAC
+	    || vga_video_type == VIDEO_TYPE_EGAM) {
+		vga_hardscroll_enabled = vga_hardscroll_user_enable;
+		vga_default_font_height = vga_si->orig_video_points;
+		vga_video_font_height = vga_si->orig_video_points;
+		/* This may be suboptimal but is a safe bet - go with it */
+		vga_scan_lines =
+		    vga_video_font_height * vga_video_num_lines;
+	}
+
+	vgacon_xres = vga_si->orig_video_cols * VGA_FONTWIDTH;
+	vgacon_yres = vga_scan_lines;
+
+	return display_desc;
+}
+
+static void vgacon_init(struct vc_data *c, bool init)
+{
+	struct uni_pagedict *p;
+
+	/*
+	 * We cannot be loaded as a module, therefore init will be 1
+	 * if we are the default console, however if we are a fallback
+	 * console, for example if fbcon has failed registration, then
+	 * init will be 0, so we need to make sure our boot parameters
+	 * have been copied to the console structure for vgacon_resize
+	 * ultimately called by vc_resize.  Any subsequent calls to
+	 * vgacon_init init will have init set to 0 too.
+	 */
+	c->vc_can_do_color = vga_can_do_color;
+	c->vc_scan_lines = vga_scan_lines;
+	c->vc_font.height = c->vc_cell_height = vga_video_font_height;
+
+	/* set dimensions manually if init is true since vc_resize() will fail */
+	if (init) {
+		c->vc_cols = vga_video_num_columns;
+		c->vc_rows = vga_video_num_lines;
+	} else
+		vc_resize(c, vga_video_num_columns, vga_video_num_lines);
+
+	c->vc_complement_mask = 0x7700;
+	if (vga_512_chars)
+		c->vc_hi_font_mask = 0x0800;
+	p = *c->uni_pagedict_loc;
+	if (c->uni_pagedict_loc != &vgacon_uni_pagedir) {
+		con_free_unimap(c);
+		c->uni_pagedict_loc = &vgacon_uni_pagedir;
+		vgacon_refcount++;
+	}
+	if (!vgacon_uni_pagedir && p)
+		con_set_default_unimap(c);
+
+	/* Only set the default if the user didn't deliberately override it */
+	if (global_cursor_default == -1)
+		global_cursor_default =
+			!(vga_si->flags & VIDEO_FLAGS_NOCURSOR);
+}
+
+static void vgacon_deinit(struct vc_data *c)
+{
+	/* When closing the active console, reset video origin */
+	if (con_is_visible(c)) {
+		c->vc_visible_origin = vga_vram_base;
+		vga_set_mem_top(c);
+	}
+
+	if (!--vgacon_refcount)
+		con_free_unimap(c);
+	c->uni_pagedict_loc = &c->uni_pagedict;
+	con_set_default_unimap(c);
+}
+
+static u8 vgacon_build_attr(struct vc_data *c, u8 color,
+			    enum vc_intensity intensity,
+			    bool blink, bool underline, bool reverse,
+			    bool italic)
+{
+	u8 attr = color;
+
+	if (vga_can_do_color) {
+		if (italic)
+			attr = (attr & 0xF0) | c->vc_itcolor;
+		else if (underline)
+			attr = (attr & 0xf0) | c->vc_ulcolor;
+		else if (intensity == VCI_HALF_BRIGHT)
+			attr = (attr & 0xf0) | c->vc_halfcolor;
+	}
+	if (reverse)
+		attr =
+		    ((attr) & 0x88) | ((((attr) >> 4) | ((attr) << 4)) &
+				       0x77);
+	if (blink)
+		attr ^= 0x80;
+	if (intensity == VCI_BOLD)
+		attr ^= 0x08;
+	if (!vga_can_do_color) {
+		if (italic)
+			attr = (attr & 0xF8) | 0x02;
+		else if (underline)
+			attr = (attr & 0xf8) | 0x01;
+		else if (intensity == VCI_HALF_BRIGHT)
+			attr = (attr & 0xf0) | 0x08;
+	}
+	return attr;
+}
+
+static void vgacon_invert_region(struct vc_data *c, u16 * p, int count)
+{
+	const bool col = vga_can_do_color;
+
+	while (count--) {
+		u16 a = scr_readw(p);
+		if (col)
+			a = ((a) & 0x88ff) | (((a) & 0x7000) >> 4) |
+			    (((a) & 0x0700) << 4);
+		else
+			a ^= ((a & 0x0700) == 0x0100) ? 0x7000 : 0x7700;
+		scr_writew(a, p++);
+	}
+}
+
+static void vgacon_set_cursor_size(int from, int to)
+{
+	unsigned long flags;
+	int curs, cure;
+
+	if ((from == cursor_size_lastfrom) && (to == cursor_size_lastto))
+		return;
+	cursor_size_lastfrom = from;
+	cursor_size_lastto = to;
+
+	raw_spin_lock_irqsave(&vga_lock, flags);
+	if (vga_video_type >= VIDEO_TYPE_VGAC) {
+		outb_p(VGA_CRTC_CURSOR_START, vga_video_port_reg);
+		curs = inb_p(vga_video_port_val);
+		outb_p(VGA_CRTC_CURSOR_END, vga_video_port_reg);
+		cure = inb_p(vga_video_port_val);
+	} else {
+		curs = 0;
+		cure = 0;
+	}
+
+	curs = (curs & 0xc0) | from;
+	cure = (cure & 0xe0) | to;
+
+	outb_p(VGA_CRTC_CURSOR_START, vga_video_port_reg);
+	outb_p(curs, vga_video_port_val);
+	outb_p(VGA_CRTC_CURSOR_END, vga_video_port_reg);
+	outb_p(cure, vga_video_port_val);
+	raw_spin_unlock_irqrestore(&vga_lock, flags);
+}
+
+static void vgacon_cursor(struct vc_data *c, bool enable)
+{
+	unsigned int c_height;
+
+	if (c->vc_mode != KD_TEXT)
+		return;
+
+	vgacon_restore_screen(c);
+
+	c_height = c->vc_cell_height;
+
+	write_vga(14, (c->vc_pos - vga_vram_base) / 2);
+
+	if (!enable) {
+	        if (vga_video_type >= VIDEO_TYPE_VGAC)
+			vgacon_set_cursor_size(31, 30);
+		else
+			vgacon_set_cursor_size(31, 31);
+		return;
+	}
+
+	switch (CUR_SIZE(c->vc_cursor_type)) {
+	case CUR_UNDERLINE:
+		vgacon_set_cursor_size(c_height - (c_height < 10 ? 2 : 3),
+				       c_height - (c_height < 10 ? 1 : 2));
+		break;
+	case CUR_TWO_THIRDS:
+		vgacon_set_cursor_size(c_height / 3,
+				       c_height - (c_height < 10 ? 1 : 2));
+		break;
+	case CUR_LOWER_THIRD:
+		vgacon_set_cursor_size(c_height * 2 / 3,
+				       c_height - (c_height < 10 ? 1 : 2));
+		break;
+	case CUR_LOWER_HALF:
+		vgacon_set_cursor_size(c_height / 2,
+				       c_height - (c_height < 10 ? 1 : 2));
+		break;
+	case CUR_NONE:
+		if (vga_video_type >= VIDEO_TYPE_VGAC)
+			vgacon_set_cursor_size(31, 30);
+		else
+			vgacon_set_cursor_size(31, 31);
+		break;
+	default:
+		vgacon_set_cursor_size(1, c_height);
+		break;
+	}
+}
+
+static void vgacon_doresize(struct vc_data *c,
+		unsigned int width, unsigned int height)
+{
+	unsigned long flags;
+	unsigned int scanlines = height * c->vc_cell_height;
+	u8 scanlines_lo = 0, r7 = 0, vsync_end = 0, mode, max_scan;
+
+	raw_spin_lock_irqsave(&vga_lock, flags);
+
+	vgacon_xres = width * VGA_FONTWIDTH;
+	vgacon_yres = height * c->vc_cell_height;
+	if (vga_video_type >= VIDEO_TYPE_VGAC) {
+		outb_p(VGA_CRTC_MAX_SCAN, vga_video_port_reg);
+		max_scan = inb_p(vga_video_port_val);
+
+		if (max_scan & 0x80)
+			scanlines <<= 1;
+
+		outb_p(VGA_CRTC_MODE, vga_video_port_reg);
+		mode = inb_p(vga_video_port_val);
+
+		if (mode & 0x04)
+			scanlines >>= 1;
+
+		scanlines -= 1;
+		scanlines_lo = scanlines & 0xff;
+
+		outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);
+		r7 = inb_p(vga_video_port_val) & ~0x42;
+
+		if (scanlines & 0x100)
+			r7 |= 0x02;
+		if (scanlines & 0x200)
+			r7 |= 0x40;
+
+		/* deprotect registers */
+		outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);
+		vsync_end = inb_p(vga_video_port_val);
+		outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);
+		outb_p(vsync_end & ~0x80, vga_video_port_val);
+	}
+
+	outb_p(VGA_CRTC_H_DISP, vga_video_port_reg);
+	outb_p(width - 1, vga_video_port_val);
+	outb_p(VGA_CRTC_OFFSET, vga_video_port_reg);
+	outb_p(width >> 1, vga_video_port_val);
+
+	if (vga_video_type >= VIDEO_TYPE_VGAC) {
+		outb_p(VGA_CRTC_V_DISP_END, vga_video_port_reg);
+		outb_p(scanlines_lo, vga_video_port_val);
+		outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);
+		outb_p(r7,vga_video_port_val);
+
+		/* reprotect registers */
+		outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);
+		outb_p(vsync_end, vga_video_port_val);
+	}
+
+	raw_spin_unlock_irqrestore(&vga_lock, flags);
+}
+
+static bool vgacon_switch(struct vc_data *c)
+{
+	int x = c->vc_cols * VGA_FONTWIDTH;
+	int y = c->vc_rows * c->vc_cell_height;
+	int rows = vga_si->orig_video_lines * vga_default_font_height/
+		c->vc_cell_height;
+	/*
+	 * We need to save screen size here as it's the only way
+	 * we can spot the screen has been resized and we need to
+	 * set size of freshly allocated screens ourselves.
+	 */
+	vga_video_num_columns = c->vc_cols;
+	vga_video_num_lines = c->vc_rows;
+
+	/* We can only copy out the size of the video buffer here,
+	 * otherwise we get into VGA BIOS */
+
+	if (!vga_is_gfx) {
+		scr_memcpyw((u16 *) c->vc_origin, (u16 *) c->vc_screenbuf,
+			    c->vc_screenbuf_size > vga_vram_size ?
+				vga_vram_size : c->vc_screenbuf_size);
+
+		if ((vgacon_xres != x || vgacon_yres != y) &&
+		    (!(vga_video_num_columns % 2) &&
+		     vga_video_num_columns <= vga_si->orig_video_cols &&
+		     vga_video_num_lines <= rows))
+			vgacon_doresize(c, c->vc_cols, c->vc_rows);
+	}
+
+	return false;		/* Redrawing not needed */
+}
+
+static void vga_set_palette(struct vc_data *vc, const unsigned char *table)
+{
+	int i, j;
+
+	vga_w(vgastate.vgabase, VGA_PEL_MSK, 0xff);
+	for (i = j = 0; i < 16; i++) {
+		vga_w(vgastate.vgabase, VGA_PEL_IW, table[i]);
+		vga_w(vgastate.vgabase, VGA_PEL_D, vc->vc_palette[j++] >> 2);
+		vga_w(vgastate.vgabase, VGA_PEL_D, vc->vc_palette[j++] >> 2);
+		vga_w(vgastate.vgabase, VGA_PEL_D, vc->vc_palette[j++] >> 2);
+	}
+}
+
+static void vgacon_set_palette(struct vc_data *vc, const unsigned char *table)
+{
+	if (vga_video_type != VIDEO_TYPE_VGAC || vga_palette_blanked
+	    || !con_is_visible(vc))
+		return;
+	vga_set_palette(vc, table);
+}
+
+/* structure holding original VGA register settings */
+static struct {
+	unsigned char SeqCtrlIndex;	/* Sequencer Index reg.   */
+	unsigned char CrtCtrlIndex;	/* CRT-Contr. Index reg.  */
+	unsigned char CrtMiscIO;	/* Miscellaneous register */
+	unsigned char HorizontalTotal;	/* CRT-Controller:00h */
+	unsigned char HorizDisplayEnd;	/* CRT-Controller:01h */
+	unsigned char StartHorizRetrace;	/* CRT-Controller:04h */
+	unsigned char EndHorizRetrace;	/* CRT-Controller:05h */
+	unsigned char Overflow;	/* CRT-Controller:07h */
+	unsigned char StartVertRetrace;	/* CRT-Controller:10h */
+	unsigned char EndVertRetrace;	/* CRT-Controller:11h */
+	unsigned char ModeControl;	/* CRT-Controller:17h */
+	unsigned char ClockingMode;	/* Seq-Controller:01h */
+} vga_state;
+
+static void vga_vesa_blank(struct vgastate *state, enum vesa_blank_mode mode)
+{
+	/* save original values of VGA controller registers */
+	if (!vga_vesa_blanked) {
+		raw_spin_lock_irq(&vga_lock);
+		vga_state.SeqCtrlIndex = vga_r(state->vgabase, VGA_SEQ_I);
+		vga_state.CrtCtrlIndex = inb_p(vga_video_port_reg);
+		vga_state.CrtMiscIO = vga_r(state->vgabase, VGA_MIS_R);
+		raw_spin_unlock_irq(&vga_lock);
+
+		outb_p(0x00, vga_video_port_reg);	/* HorizontalTotal */
+		vga_state.HorizontalTotal = inb_p(vga_video_port_val);
+		outb_p(0x01, vga_video_port_reg);	/* HorizDisplayEnd */
+		vga_state.HorizDisplayEnd = inb_p(vga_video_port_val);
+		outb_p(0x04, vga_video_port_reg);	/* StartHorizRetrace */
+		vga_state.StartHorizRetrace = inb_p(vga_video_port_val);
+		outb_p(0x05, vga_video_port_reg);	/* EndHorizRetrace */
+		vga_state.EndHorizRetrace = inb_p(vga_video_port_val);
+		outb_p(0x07, vga_video_port_reg);	/* Overflow */
+		vga_state.Overflow = inb_p(vga_video_port_val);
+		outb_p(0x10, vga_video_port_reg);	/* StartVertRetrace */
+		vga_state.StartVertRetrace = inb_p(vga_video_port_val);
+		outb_p(0x11, vga_video_port_reg);	/* EndVertRetrace */
+		vga_state.EndVertRetrace = inb_p(vga_video_port_val);
+		outb_p(0x17, vga_video_port_reg);	/* ModeControl */
+		vga_state.ModeControl = inb_p(vga_video_port_val);
+		vga_state.ClockingMode = vga_rseq(state->vgabase, VGA_SEQ_CLOCK_MODE);
+	}
+
+	/* assure that video is enabled */
+	/* "0x20" is VIDEO_ENABLE_bit in register 01 of sequencer */
+	raw_spin_lock_irq(&vga_lock);
+	vga_wseq(state->vgabase, VGA_SEQ_CLOCK_MODE, vga_state.ClockingMode | 0x20);
+
+	/* test for vertical retrace in process.... */
+	if ((vga_state.CrtMiscIO & 0x80) == 0x80)
+		vga_w(state->vgabase, VGA_MIS_W, vga_state.CrtMiscIO & 0xEF);
+
+	/*
+	 * Set <End of vertical retrace> to minimum (0) and
+	 * <Start of vertical Retrace> to maximum (incl. overflow)
+	 * Result: turn off vertical sync (VSync) pulse.
+	 */
+	if (mode & VESA_VSYNC_SUSPEND) {
+		outb_p(0x10, vga_video_port_reg);	/* StartVertRetrace */
+		outb_p(0xff, vga_video_port_val);	/* maximum value */
+		outb_p(0x11, vga_video_port_reg);	/* EndVertRetrace */
+		outb_p(0x40, vga_video_port_val);	/* minimum (bits 0..3)  */
+		outb_p(0x07, vga_video_port_reg);	/* Overflow */
+		outb_p(vga_state.Overflow | 0x84, vga_video_port_val);	/* bits 9,10 of vert. retrace */
+	}
+
+	if (mode & VESA_HSYNC_SUSPEND) {
+		/*
+		 * Set <End of horizontal retrace> to minimum (0) and
+		 *  <Start of horizontal Retrace> to maximum
+		 * Result: turn off horizontal sync (HSync) pulse.
+		 */
+		outb_p(0x04, vga_video_port_reg);	/* StartHorizRetrace */
+		outb_p(0xff, vga_video_port_val);	/* maximum */
+		outb_p(0x05, vga_video_port_reg);	/* EndHorizRetrace */
+		outb_p(0x00, vga_video_port_val);	/* minimum (0) */
+	}
+
+	/* restore both index registers */
+	vga_w(state->vgabase, VGA_SEQ_I, vga_state.SeqCtrlIndex);
+	outb_p(vga_state.CrtCtrlIndex, vga_video_port_reg);
+	raw_spin_unlock_irq(&vga_lock);
+}
+
+static void vga_vesa_unblank(struct vgastate *state)
+{
+	/* restore original values of VGA controller registers */
+	raw_spin_lock_irq(&vga_lock);
+	vga_w(state->vgabase, VGA_MIS_W, vga_state.CrtMiscIO);
+
+	outb_p(0x00, vga_video_port_reg);	/* HorizontalTotal */
+	outb_p(vga_state.HorizontalTotal, vga_video_port_val);
+	outb_p(0x01, vga_video_port_reg);	/* HorizDisplayEnd */
+	outb_p(vga_state.HorizDisplayEnd, vga_video_port_val);
+	outb_p(0x04, vga_video_port_reg);	/* StartHorizRetrace */
+	outb_p(vga_state.StartHorizRetrace, vga_video_port_val);
+	outb_p(0x05, vga_video_port_reg);	/* EndHorizRetrace */
+	outb_p(vga_state.EndHorizRetrace, vga_video_port_val);
+	outb_p(0x07, vga_video_port_reg);	/* Overflow */
+	outb_p(vga_state.Overflow, vga_video_port_val);
+	outb_p(0x10, vga_video_port_reg);	/* StartVertRetrace */
+	outb_p(vga_state.StartVertRetrace, vga_video_port_val);
+	outb_p(0x11, vga_video_port_reg);	/* EndVertRetrace */
+	outb_p(vga_state.EndVertRetrace, vga_video_port_val);
+	outb_p(0x17, vga_video_port_reg);	/* ModeControl */
+	outb_p(vga_state.ModeControl, vga_video_port_val);
+	/* ClockingMode */
+	vga_wseq(state->vgabase, VGA_SEQ_CLOCK_MODE, vga_state.ClockingMode);
+
+	/* restore index/control registers */
+	vga_w(state->vgabase, VGA_SEQ_I, vga_state.SeqCtrlIndex);
+	outb_p(vga_state.CrtCtrlIndex, vga_video_port_reg);
+	raw_spin_unlock_irq(&vga_lock);
+}
+
+static void vga_pal_blank(struct vgastate *state)
+{
+	int i;
+
+	vga_w(state->vgabase, VGA_PEL_MSK, 0xff);
+	for (i = 0; i < 16; i++) {
+		vga_w(state->vgabase, VGA_PEL_IW, i);
+		vga_w(state->vgabase, VGA_PEL_D, 0);
+		vga_w(state->vgabase, VGA_PEL_D, 0);
+		vga_w(state->vgabase, VGA_PEL_D, 0);
+	}
+}
+
+static bool vgacon_blank(struct vc_data *c, enum vesa_blank_mode blank,
+			 bool mode_switch)
+{
+	switch (blank) {
+	case VESA_NO_BLANKING:		/* Unblank */
+		if (vga_vesa_blanked) {
+			vga_vesa_unblank(&vgastate);
+			vga_vesa_blanked = VESA_NO_BLANKING;
+		}
+		if (vga_palette_blanked) {
+			vga_set_palette(c, color_table);
+			vga_palette_blanked = false;
+			return 0;
+		}
+		vga_is_gfx = false;
+		/* Tell console.c that it has to restore the screen itself */
+		return 1;
+	case VESA_VSYNC_SUSPEND:	/* Normal blanking */
+		if (!mode_switch && vga_video_type == VIDEO_TYPE_VGAC) {
+			vga_pal_blank(&vgastate);
+			vga_palette_blanked = true;
+			return 0;
+		}
+		vgacon_set_origin(c);
+		scr_memsetw((void *) vga_vram_base, BLANK,
+			    c->vc_screenbuf_size);
+		if (mode_switch)
+			vga_is_gfx = true;
+		return 1;
+	default:		/* VESA blanking */
+		if (vga_video_type == VIDEO_TYPE_VGAC) {
+			vga_vesa_blank(&vgastate, blank - 1);
+			vga_vesa_blanked = blank;
+		}
+		return 0;
+	}
+}
+
+/*
+ * PIO_FONT support.
+ *
+ * The font loading code goes back to the codepage package by
+ * Joel Hoffman (joel@wam.umd.edu). (He reports that the original
+ * reference is: "From: p. 307 of _Programmer's Guide to PC & PS/2
+ * Video Systems_ by Richard Wilton. 1987.  Microsoft Press".)
+ *
+ * Change for certain monochrome monitors by Yury Shevchuck
+ * (sizif@botik.yaroslavl.su).
+ */
+
+#define colourmap 0xa0000
+/* Pauline Middelink <middelin@polyware.iaf.nl> reports that we
+   should use 0xA0000 for the bwmap as well.. */
+#define blackwmap 0xa0000
+#define cmapsz 8192
+
+static int vgacon_do_font_op(struct vgastate *state, char *arg, int set,
+		bool ch512)
+{
+	unsigned short video_port_status = vga_video_port_reg + 6;
+	int font_select = 0x00, beg, i;
+	char *charmap;
+	bool clear_attribs = false;
+	if (vga_video_type != VIDEO_TYPE_EGAM) {
+		charmap = (char *) VGA_MAP_MEM(colourmap, 0);
+		beg = 0x0e;
+	} else {
+		charmap = (char *) VGA_MAP_MEM(blackwmap, 0);
+		beg = 0x0a;
+	}
+
+	/*
+	 * All fonts are loaded in slot 0 (0:1 for 512 ch)
+	 */
+
+	if (!arg)
+		return -EINVAL;	/* Return to default font not supported */
+
+	font_select = ch512 ? 0x04 : 0x00;
+
+	raw_spin_lock_irq(&vga_lock);
+	/* First, the Sequencer */
+	vga_wseq(state->vgabase, VGA_SEQ_RESET, 0x1);
+	/* CPU writes only to map 2 */
+	vga_wseq(state->vgabase, VGA_SEQ_PLANE_WRITE, 0x04);	
+	/* Sequential addressing */
+	vga_wseq(state->vgabase, VGA_SEQ_MEMORY_MODE, 0x07);	
+	/* Clear synchronous reset */
+	vga_wseq(state->vgabase, VGA_SEQ_RESET, 0x03);
+
+	/* Now, the graphics controller, select map 2 */
+	vga_wgfx(state->vgabase, VGA_GFX_PLANE_READ, 0x02);		
+	/* disable odd-even addressing */
+	vga_wgfx(state->vgabase, VGA_GFX_MODE, 0x00);
+	/* map start at A000:0000 */
+	vga_wgfx(state->vgabase, VGA_GFX_MISC, 0x00);
+	raw_spin_unlock_irq(&vga_lock);
+
+	if (arg) {
+		if (set)
+			for (i = 0; i < cmapsz; i++) {
+				vga_writeb(arg[i], charmap + i);
+				cond_resched();
+			}
+		else
+			for (i = 0; i < cmapsz; i++) {
+				arg[i] = vga_readb(charmap + i);
+				cond_resched();
+			}
+
+		/*
+		 * In 512-character mode, the character map is not contiguous if
+		 * we want to remain EGA compatible -- which we do
+		 */
+
+		if (ch512) {
+			charmap += 2 * cmapsz;
+			arg += cmapsz;
+			if (set)
+				for (i = 0; i < cmapsz; i++) {
+					vga_writeb(arg[i], charmap + i);
+					cond_resched();
+				}
+			else
+				for (i = 0; i < cmapsz; i++) {
+					arg[i] = vga_readb(charmap + i);
+					cond_resched();
+				}
+		}
+	}
+
+	raw_spin_lock_irq(&vga_lock);
+	/* First, the sequencer, Synchronous reset */
+	vga_wseq(state->vgabase, VGA_SEQ_RESET, 0x01);	
+	/* CPU writes to maps 0 and 1 */
+	vga_wseq(state->vgabase, VGA_SEQ_PLANE_WRITE, 0x03);
+	/* odd-even addressing */
+	vga_wseq(state->vgabase, VGA_SEQ_MEMORY_MODE, 0x03);
+	/* Character Map Select */
+	if (set)
+		vga_wseq(state->vgabase, VGA_SEQ_CHARACTER_MAP, font_select);
+	/* clear synchronous reset */
+	vga_wseq(state->vgabase, VGA_SEQ_RESET, 0x03);
+
+	/* Now, the graphics controller, select map 0 for CPU */
+	vga_wgfx(state->vgabase, VGA_GFX_PLANE_READ, 0x00);
+	/* enable even-odd addressing */
+	vga_wgfx(state->vgabase, VGA_GFX_MODE, 0x10);
+	/* map starts at b800:0 or b000:0 */
+	vga_wgfx(state->vgabase, VGA_GFX_MISC, beg);
+
+	/* if 512 char mode is already enabled don't re-enable it. */
+	if ((set) && (ch512 != vga_512_chars)) {
+		vga_512_chars = ch512;
+		/* 256-char: enable intensity bit
+		   512-char: disable intensity bit */
+		inb_p(video_port_status);	/* clear address flip-flop */
+		/* color plane enable register */
+		vga_wattr(state->vgabase, VGA_ATC_PLANE_ENABLE, ch512 ? 0x07 : 0x0f);
+		/* Wilton (1987) mentions the following; I don't know what
+		   it means, but it works, and it appears necessary */
+		inb_p(video_port_status);
+		vga_wattr(state->vgabase, VGA_AR_ENABLE_DISPLAY, 0);	
+		clear_attribs = true;
+	}
+	raw_spin_unlock_irq(&vga_lock);
+
+	if (clear_attribs) {
+		for (i = 0; i < MAX_NR_CONSOLES; i++) {
+			struct vc_data *c = vc_cons[i].d;
+			if (c && c->vc_sw == &vga_con) {
+				/* force hi font mask to 0, so we always clear
+				   the bit on either transition */
+				c->vc_hi_font_mask = 0x00;
+				clear_buffer_attributes(c);
+				c->vc_hi_font_mask = ch512 ? 0x0800 : 0;
+			}
+		}
+	}
+	return 0;
+}
+
+/*
+ * Adjust the screen to fit a font of a certain height
+ */
+static int vgacon_adjust_height(struct vc_data *vc, unsigned fontheight)
+{
+	unsigned char ovr, vde, fsr;
+	int rows, maxscan, i;
+
+	rows = vc->vc_scan_lines / fontheight;	/* Number of video rows we end up with */
+	maxscan = rows * fontheight - 1;	/* Scan lines to actually display-1 */
+
+	/* Reprogram the CRTC for the new font size
+	   Note: the attempt to read the overflow register will fail
+	   on an EGA, but using 0xff for the previous value appears to
+	   be OK for EGA text modes in the range 257-512 scan lines, so I
+	   guess we don't need to worry about it.
+
+	   The same applies for the spill bits in the font size and cursor
+	   registers; they are write-only on EGA, but it appears that they
+	   are all don't care bits on EGA, so I guess it doesn't matter. */
+
+	raw_spin_lock_irq(&vga_lock);
+	outb_p(0x07, vga_video_port_reg);	/* CRTC overflow register */
+	ovr = inb_p(vga_video_port_val);
+	outb_p(0x09, vga_video_port_reg);	/* Font size register */
+	fsr = inb_p(vga_video_port_val);
+	raw_spin_unlock_irq(&vga_lock);
+
+	vde = maxscan & 0xff;	/* Vertical display end reg */
+	ovr = (ovr & 0xbd) +	/* Overflow register */
+	    ((maxscan & 0x100) >> 7) + ((maxscan & 0x200) >> 3);
+	fsr = (fsr & 0xe0) + (fontheight - 1);	/*  Font size register */
+
+	raw_spin_lock_irq(&vga_lock);
+	outb_p(0x07, vga_video_port_reg);	/* CRTC overflow register */
+	outb_p(ovr, vga_video_port_val);
+	outb_p(0x09, vga_video_port_reg);	/* Font size */
+	outb_p(fsr, vga_video_port_val);
+	outb_p(0x12, vga_video_port_reg);	/* Vertical display limit */
+	outb_p(vde, vga_video_port_val);
+	raw_spin_unlock_irq(&vga_lock);
+	vga_video_font_height = fontheight;
+
+	for (i = 0; i < MAX_NR_CONSOLES; i++) {
+		struct vc_data *c = vc_cons[i].d;
+
+		if (c && c->vc_sw == &vga_con) {
+			if (con_is_visible(c)) {
+			        /* void size to cause regs to be rewritten */
+				cursor_size_lastfrom = 0;
+				cursor_size_lastto = 0;
+				c->vc_sw->con_cursor(c, true);
+			}
+			c->vc_font.height = c->vc_cell_height = fontheight;
+			vc_resize(c, 0, rows);	/* Adjust console size */
+		}
+	}
+	return 0;
+}
+
+static int vgacon_font_set(struct vc_data *c, const struct console_font *font,
+			   unsigned int vpitch, unsigned int flags)
+{
+	unsigned charcount = font->charcount;
+	int rc;
+
+	if (vga_video_type < VIDEO_TYPE_EGAM)
+		return -EINVAL;
+
+	if (font->width != VGA_FONTWIDTH || font->height > 32 || vpitch != 32 ||
+	    (charcount != 256 && charcount != 512))
+		return -EINVAL;
+
+	rc = vgacon_do_font_op(&vgastate, font->data, 1, charcount == 512);
+	if (rc)
+		return rc;
+
+	if (!(flags & KD_FONT_FLAG_DONT_RECALC))
+		rc = vgacon_adjust_height(c, font->height);
+	return rc;
+}
+
+static int vgacon_font_get(struct vc_data *c, struct console_font *font, unsigned int vpitch)
+{
+	if (vga_video_type < VIDEO_TYPE_EGAM || vpitch != 32)
+		return -EINVAL;
+
+	font->width = VGA_FONTWIDTH;
+	font->height = c->vc_font.height;
+	font->charcount = vga_512_chars ? 512 : 256;
+	if (!font->data)
+		return 0;
+	return vgacon_do_font_op(&vgastate, font->data, 0, vga_512_chars);
+}
+
+static int vgacon_resize(struct vc_data *c, unsigned int width,
+			 unsigned int height, bool from_user)
+{
+	if ((width << 1) * height > vga_vram_size)
+		return -EINVAL;
+
+	if (from_user) {
+		/*
+		 * Ho ho!  Someone (svgatextmode, eh?) may have reprogrammed
+		 * the video mode!  Set the new defaults then and go away.
+		 */
+		vga_si->orig_video_cols = width;
+		vga_si->orig_video_lines = height;
+		vga_default_font_height = c->vc_cell_height;
+		return 0;
+	}
+	if (width % 2 || width > vga_si->orig_video_cols ||
+	    height > (vga_si->orig_video_lines * vga_default_font_height)/
+	    c->vc_cell_height)
+		return -EINVAL;
+
+	if (con_is_visible(c) && !vga_is_gfx) /* who knows */
+		vgacon_doresize(c, width, height);
+	return 0;
+}
+
+static bool vgacon_set_origin(struct vc_data *c)
+{
+	if (vga_is_gfx ||	/* We don't play origin tricks in graphic modes */
+	    (console_blanked && !vga_palette_blanked))	/* Nor we write to blanked screens */
+		return false;
+	c->vc_origin = c->vc_visible_origin = vga_vram_base;
+	vga_set_mem_top(c);
+	vga_rolled_over = 0;
+	return true;
+}
+
+static void vgacon_save_screen(struct vc_data *c)
+{
+	static int vga_bootup_console = 0;
+
+	if (!vga_bootup_console) {
+		/* This is a gross hack, but here is the only place we can
+		 * set bootup console parameters without messing up generic
+		 * console initialization routines.
+		 */
+		vga_bootup_console = 1;
+		c->state.x = vga_si->orig_x;
+		c->state.y = vga_si->orig_y;
+	}
+
+	/* We can't copy in more than the size of the video buffer,
+	 * or we'll be copying in VGA BIOS */
+
+	if (!vga_is_gfx)
+		scr_memcpyw((u16 *) c->vc_screenbuf, (u16 *) c->vc_origin,
+			    c->vc_screenbuf_size > vga_vram_size ? vga_vram_size : c->vc_screenbuf_size);
+}
+
+static bool vgacon_scroll(struct vc_data *c, unsigned int t, unsigned int b,
+		enum con_scroll dir, unsigned int lines)
+{
+	unsigned long oldo;
+	unsigned int delta;
+
+	if (t || b != c->vc_rows || vga_is_gfx || c->vc_mode != KD_TEXT)
+		return false;
+
+	if (!vga_hardscroll_enabled || lines >= c->vc_rows / 2)
+		return false;
+
+	vgacon_restore_screen(c);
+	oldo = c->vc_origin;
+	delta = lines * c->vc_size_row;
+	if (dir == SM_UP) {
+		if (c->vc_scr_end + delta >= vga_vram_end) {
+			scr_memcpyw((u16 *) vga_vram_base,
+				    (u16 *) (oldo + delta),
+				    c->vc_screenbuf_size - delta);
+			c->vc_origin = vga_vram_base;
+			vga_rolled_over = oldo - vga_vram_base;
+		} else
+			c->vc_origin += delta;
+		scr_memsetw((u16 *) (c->vc_origin + c->vc_screenbuf_size -
+				     delta), c->vc_video_erase_char,
+			    delta);
+	} else {
+		if (oldo - delta < vga_vram_base) {
+			scr_memmovew((u16 *) (vga_vram_end -
+					      c->vc_screenbuf_size +
+					      delta), (u16 *) oldo,
+				     c->vc_screenbuf_size - delta);
+			c->vc_origin = vga_vram_end - c->vc_screenbuf_size;
+			vga_rolled_over = 0;
+		} else
+			c->vc_origin -= delta;
+		c->vc_scr_end = c->vc_origin + c->vc_screenbuf_size;
+		scr_memsetw((u16 *) (c->vc_origin), c->vc_video_erase_char,
+			    delta);
+	}
+	c->vc_scr_end = c->vc_origin + c->vc_screenbuf_size;
+	c->vc_visible_origin = c->vc_origin;
+	vga_set_mem_top(c);
+	c->vc_pos = (c->vc_pos - oldo) + c->vc_origin;
+	return true;
+}
+
+/*
+ *  The console `switch' structure for the VGA based console
+ */
+
+static void vgacon_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
+			 unsigned int width) { }
+static void vgacon_putcs(struct vc_data *vc, const u16 *s, unsigned int count,
+			 unsigned int ypos, unsigned int xpos) { }
+
+const struct consw vga_con = {
+	.owner = THIS_MODULE,
+	.con_startup = vgacon_startup,
+	.con_init = vgacon_init,
+	.con_deinit = vgacon_deinit,
+	.con_clear = vgacon_clear,
+	.con_putcs = vgacon_putcs,
+	.con_cursor = vgacon_cursor,
+	.con_scroll = vgacon_scroll,
+	.con_switch = vgacon_switch,
+	.con_blank = vgacon_blank,
+	.con_font_set = vgacon_font_set,
+	.con_font_get = vgacon_font_get,
+	.con_resize = vgacon_resize,
+	.con_set_palette = vgacon_set_palette,
+	.con_scrolldelta = vgacon_scrolldelta,
+	.con_set_origin = vgacon_set_origin,
+	.con_save_screen = vgacon_save_screen,
+	.con_build_attr = vgacon_build_attr,
+	.con_invert_region = vgacon_invert_region,
+};
+EXPORT_SYMBOL(vga_con);
+
+void vgacon_register_screen(struct screen_info *si)
+{
+	if (!si || vga_si)
+		return;
+
+	conswitchp = &vga_con;
+	vga_si = si;
+}
+
+MODULE_DESCRIPTION("VGA based console driver");
+MODULE_LICENSE("GPL");
-- 
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