cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

video-mode.c (3810B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* -*- linux-c -*- ------------------------------------------------------- *
      3 *
      4 *   Copyright (C) 1991, 1992 Linus Torvalds
      5 *   Copyright 2007-2008 rPath, Inc. - All Rights Reserved
      6 *
      7 * ----------------------------------------------------------------------- */
      8
      9/*
     10 * arch/i386/boot/video-mode.c
     11 *
     12 * Set the video mode.  This is separated out into a different
     13 * file in order to be shared with the ACPI wakeup code.
     14 */
     15
     16#include "boot.h"
     17#include "video.h"
     18#include "vesa.h"
     19
     20#include <uapi/asm/boot.h>
     21
     22/*
     23 * Common variables
     24 */
     25int adapter;		/* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */
     26int force_x, force_y;	/* Don't query the BIOS for cols/rows */
     27int do_restore;		/* Screen contents changed during mode flip */
     28int graphic_mode;	/* Graphic mode with linear frame buffer */
     29
     30/* Probe the video drivers and have them generate their mode lists. */
     31void probe_cards(int unsafe)
     32{
     33	struct card_info *card;
     34	static u8 probed[2];
     35
     36	if (probed[unsafe])
     37		return;
     38
     39	probed[unsafe] = 1;
     40
     41	for (card = video_cards; card < video_cards_end; card++) {
     42		if (card->unsafe == unsafe) {
     43			if (card->probe)
     44				card->nmodes = card->probe();
     45			else
     46				card->nmodes = 0;
     47		}
     48	}
     49}
     50
     51/* Test if a mode is defined */
     52int mode_defined(u16 mode)
     53{
     54	struct card_info *card;
     55	struct mode_info *mi;
     56	int i;
     57
     58	for (card = video_cards; card < video_cards_end; card++) {
     59		mi = card->modes;
     60		for (i = 0; i < card->nmodes; i++, mi++) {
     61			if (mi->mode == mode)
     62				return 1;
     63		}
     64	}
     65
     66	return 0;
     67}
     68
     69/* Set mode (without recalc) */
     70static int raw_set_mode(u16 mode, u16 *real_mode)
     71{
     72	int nmode, i;
     73	struct card_info *card;
     74	struct mode_info *mi;
     75
     76	/* Drop the recalc bit if set */
     77	mode &= ~VIDEO_RECALC;
     78
     79	/* Scan for mode based on fixed ID, position, or resolution */
     80	nmode = 0;
     81	for (card = video_cards; card < video_cards_end; card++) {
     82		mi = card->modes;
     83		for (i = 0; i < card->nmodes; i++, mi++) {
     84			int visible = mi->x || mi->y;
     85
     86			if ((mode == nmode && visible) ||
     87			    mode == mi->mode ||
     88			    mode == (mi->y << 8)+mi->x) {
     89				*real_mode = mi->mode;
     90				return card->set_mode(mi);
     91			}
     92
     93			if (visible)
     94				nmode++;
     95		}
     96	}
     97
     98	/* Nothing found?  Is it an "exceptional" (unprobed) mode? */
     99	for (card = video_cards; card < video_cards_end; card++) {
    100		if (mode >= card->xmode_first &&
    101		    mode < card->xmode_first+card->xmode_n) {
    102			struct mode_info mix;
    103			*real_mode = mix.mode = mode;
    104			mix.x = mix.y = 0;
    105			return card->set_mode(&mix);
    106		}
    107	}
    108
    109	/* Otherwise, failure... */
    110	return -1;
    111}
    112
    113/*
    114 * Recalculate the vertical video cutoff (hack!)
    115 */
    116static void vga_recalc_vertical(void)
    117{
    118	unsigned int font_size, rows;
    119	u16 crtc;
    120	u8 pt, ov;
    121
    122	set_fs(0);
    123	font_size = rdfs8(0x485); /* BIOS: font size (pixels) */
    124	rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */
    125
    126	rows *= font_size;	/* Visible scan lines */
    127	rows--;			/* ... minus one */
    128
    129	crtc = vga_crtc();
    130
    131	pt = in_idx(crtc, 0x11);
    132	pt &= ~0x80;		/* Unlock CR0-7 */
    133	out_idx(pt, crtc, 0x11);
    134
    135	out_idx((u8)rows, crtc, 0x12); /* Lower height register */
    136
    137	ov = in_idx(crtc, 0x07); /* Overflow register */
    138	ov &= 0xbd;
    139	ov |= (rows >> (8-1)) & 0x02;
    140	ov |= (rows >> (9-6)) & 0x40;
    141	out_idx(ov, crtc, 0x07);
    142}
    143
    144/* Set mode (with recalc if specified) */
    145int set_mode(u16 mode)
    146{
    147	int rv;
    148	u16 real_mode;
    149
    150	/* Very special mode numbers... */
    151	if (mode == VIDEO_CURRENT_MODE)
    152		return 0;	/* Nothing to do... */
    153	else if (mode == NORMAL_VGA)
    154		mode = VIDEO_80x25;
    155	else if (mode == EXTENDED_VGA)
    156		mode = VIDEO_8POINT;
    157
    158	rv = raw_set_mode(mode, &real_mode);
    159	if (rv)
    160		return rv;
    161
    162	if (mode & VIDEO_RECALC)
    163		vga_recalc_vertical();
    164
    165	/* Save the canonical mode number for the kernel, not
    166	   an alias, size specification or menu position */
    167#ifndef _WAKEUP
    168	boot_params.hdr.vid_mode = real_mode;
    169#endif
    170	return 0;
    171}