linux/arch/x86/boot/video-mode.c
Kirill A. Shutemov 70f1528747 x86/mm: Fix regression with huge pages on PAE
Recent PAT patchset has caused issue on 32-bit PAE machines:

  page:eea45000 count:0 mapcount:-128 mapping:  (null) index:0x0 flags: 0x40000000()
  page dumped because: VM_BUG_ON_PAGE(page_mapcount(page) < 0)
  ------------[ cut here ]------------
  kernel BUG at /home/build/linux-boris/mm/huge_memory.c:1485!
  invalid opcode: 0000 [#1] SMP
  [...]
  Call Trace:
   unmap_single_vma
   ? __wake_up
   unmap_vmas
   unmap_region
   do_munmap
   vm_munmap
   SyS_munmap
   do_fast_syscall_32
   ? __do_page_fault
   sysenter_past_esp
  Code: ...
  EIP: [<c11bde80>] zap_huge_pmd+0x240/0x260 SS:ESP 0068:f6459d98

The problem is in pmd_pfn_mask() and pmd_flags_mask(). These
helpers use PMD_PAGE_MASK to calculate resulting mask.
PMD_PAGE_MASK is 'unsigned long', not 'unsigned long long' as
phys_addr_t is on 32-bit PAE (ARCH_PHYS_ADDR_T_64BIT). As a
result, the upper bits of resulting mask get truncated.

pud_pfn_mask() and pud_flags_mask() aren't problematic since we
don't have PUD page table level on 32-bit systems, but it's
reasonable to keep them consistent with PMD counterpart.

Introduce PHYSICAL_PMD_PAGE_MASK and PHYSICAL_PUD_PAGE_MASK in
addition to existing PHYSICAL_PAGE_MASK and reworks helpers to
use them.

Reported-and-Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
[ Fix -Woverflow warnings from the realmode code. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jürgen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: elliott@hpe.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Fixes: f70abb0fc3 ("x86/asm: Fix pud/pmd interfaces to handle large PAT bit")
Link: http://lkml.kernel.org/r/1448878233-11390-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-12-04 09:14:27 +01:00

174 lines
3.8 KiB
C

/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007-2008 rPath, Inc. - All Rights Reserved
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* ----------------------------------------------------------------------- */
/*
* arch/i386/boot/video-mode.c
*
* Set the video mode. This is separated out into a different
* file in order to be shared with the ACPI wakeup code.
*/
#include "boot.h"
#include "video.h"
#include "vesa.h"
#include <uapi/asm/boot.h>
/*
* Common variables
*/
int adapter; /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */
int force_x, force_y; /* Don't query the BIOS for cols/rows */
int do_restore; /* Screen contents changed during mode flip */
int graphic_mode; /* Graphic mode with linear frame buffer */
/* Probe the video drivers and have them generate their mode lists. */
void probe_cards(int unsafe)
{
struct card_info *card;
static u8 probed[2];
if (probed[unsafe])
return;
probed[unsafe] = 1;
for (card = video_cards; card < video_cards_end; card++) {
if (card->unsafe == unsafe) {
if (card->probe)
card->nmodes = card->probe();
else
card->nmodes = 0;
}
}
}
/* Test if a mode is defined */
int mode_defined(u16 mode)
{
struct card_info *card;
struct mode_info *mi;
int i;
for (card = video_cards; card < video_cards_end; card++) {
mi = card->modes;
for (i = 0; i < card->nmodes; i++, mi++) {
if (mi->mode == mode)
return 1;
}
}
return 0;
}
/* Set mode (without recalc) */
static int raw_set_mode(u16 mode, u16 *real_mode)
{
int nmode, i;
struct card_info *card;
struct mode_info *mi;
/* Drop the recalc bit if set */
mode &= ~VIDEO_RECALC;
/* Scan for mode based on fixed ID, position, or resolution */
nmode = 0;
for (card = video_cards; card < video_cards_end; card++) {
mi = card->modes;
for (i = 0; i < card->nmodes; i++, mi++) {
int visible = mi->x || mi->y;
if ((mode == nmode && visible) ||
mode == mi->mode ||
mode == (mi->y << 8)+mi->x) {
*real_mode = mi->mode;
return card->set_mode(mi);
}
if (visible)
nmode++;
}
}
/* Nothing found? Is it an "exceptional" (unprobed) mode? */
for (card = video_cards; card < video_cards_end; card++) {
if (mode >= card->xmode_first &&
mode < card->xmode_first+card->xmode_n) {
struct mode_info mix;
*real_mode = mix.mode = mode;
mix.x = mix.y = 0;
return card->set_mode(&mix);
}
}
/* Otherwise, failure... */
return -1;
}
/*
* Recalculate the vertical video cutoff (hack!)
*/
static void vga_recalc_vertical(void)
{
unsigned int font_size, rows;
u16 crtc;
u8 pt, ov;
set_fs(0);
font_size = rdfs8(0x485); /* BIOS: font size (pixels) */
rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */
rows *= font_size; /* Visible scan lines */
rows--; /* ... minus one */
crtc = vga_crtc();
pt = in_idx(crtc, 0x11);
pt &= ~0x80; /* Unlock CR0-7 */
out_idx(pt, crtc, 0x11);
out_idx((u8)rows, crtc, 0x12); /* Lower height register */
ov = in_idx(crtc, 0x07); /* Overflow register */
ov &= 0xbd;
ov |= (rows >> (8-1)) & 0x02;
ov |= (rows >> (9-6)) & 0x40;
out_idx(ov, crtc, 0x07);
}
/* Set mode (with recalc if specified) */
int set_mode(u16 mode)
{
int rv;
u16 real_mode;
/* Very special mode numbers... */
if (mode == VIDEO_CURRENT_MODE)
return 0; /* Nothing to do... */
else if (mode == NORMAL_VGA)
mode = VIDEO_80x25;
else if (mode == EXTENDED_VGA)
mode = VIDEO_8POINT;
rv = raw_set_mode(mode, &real_mode);
if (rv)
return rv;
if (mode & VIDEO_RECALC)
vga_recalc_vertical();
/* Save the canonical mode number for the kernel, not
an alias, size specification or menu position */
#ifndef _WAKEUP
boot_params.hdr.vid_mode = real_mode;
#endif
return 0;
}