This patch introduces a restriction on /dev/mem: Only non-memory can be
read or written unless the newly introduced config option is set.

The X server needs access to /dev/mem for the PCI space, but it doesn't need
access to memory; both the file permissions and SELinux permissions of /dev/mem
just make X effectively super-super powerful. With the exception of the
BIOS area, there's just no valid app that uses /dev/mem on actual memory.
Other popular users of /dev/mem are rootkits and the like.
(note: mmap access of memory via /dev/mem was already not allowed since
a really long time)

People who want to use /dev/mem for kernel debugging can enable the config
option.

The restrictions of this patch have been in the Fedora and RHEL kernels for
at least 4 years without any problems.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Even on 32bit 2MB pages can map more memory than is in the true
max_low_pfn if end_pfn is not highmem and not aligned to 2MB.
Add a end_pfn_map similar to x86-64 that accounts for this
fact. This is important for code that really needs to know about
all mapping aliases.
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: andreas.herrmann3@amd.com
Cc: mingo@elte.hu
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Clean up: eliminate some compiler noise on x86 when building with strict
warnings enabled, introduced by commit 345b904c.

In file included from include2/asm/thread_info_64.h:12,
                 from include2/asm/thread_info.h:4,
                 from
/home/cel/src/linux/nfs-2.6/include/linux/thread_info.h:35,
                 from
/home/cel/src/linux/nfs-2.6/include/linux/preempt.h:9,
                 from
/home/cel/src/linux/nfs-2.6/include/linux/spinlock.h:49,
                 from /home/cel/src/linux/nfs-2.6/include/linux/mmzone.h:7,
                 from /home/cel/src/linux/nfs-2.6/include/linux/gfp.h:4,
                 from /home/cel/src/linux/nfs-2.6/include/linux/slab.h:14,
                 from /home/cel/src/linux/nfs-2.6/fs/nfsd/nfs4acl.c:40:
include2/asm/page.h:55: warning: `inline' is not at beginning of
declaration
include2/asm/page.h:61: warning: `inline' is not at beginning of
declaration
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Fix up all users.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

64bit uses end_pfn_map and 32bit uses max_low_pfn. There are several
files which have #ifdef'ed defines which map either to end_pfn_map or
max_low_pfn. Replace this by a universal define and clean up all the
other instances.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Make sure pte_t, whatever its definition, has a pte element with type
pteval_t.  This allows common code to access it without needing to be
specifically parameterised on what pagetable mode we're compiling for.
For 32-bit, this means that pte_t becomes a union with "pte" and "{
pte_low, pte_high }" (PAE) or just "pte_low" (non-PAE).
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

fix sign extension bug in PTE_MASK / _PTE_CHG_MASK.

this resolves the following bootup crash on PAE systems:

[   94.710726] init[1]: segfault at 00000004 ip 49471cbb sp bff0c6c0 error 4
[   94.717764] init[1]: segfault at 00000004 ip 49471cbb sp bff0c6c0 error 4
[   94.724772] init[1]: segfault at 00000004 ip 49471cbb sp bff0c6c0 error 4
[   94.731777] init[1]: segfault at 00000004 ip 49471cbb sp bff0c6c0 error 4
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

# HG changeset patch
# User Jeremy Fitzhardinge <jeremy@xensource.com>
# Date 1199321648 28800
# Node ID 22f6a5902285b58bfc1fbbd9e183498c9017bd78
# Parent  bba9287641ff90e836d090d80b5c0a846aab7162
x86: page.h: move things back to their own files

Oops, asm/page.h has turned into an #ifdef hellhole.  Move
32/64-specific things back to their own headers to make it somewhat
comprehensible...
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

# HG changeset patch
# User Jeremy Fitzhardinge <jeremy@xensource.com>
# Date 1199319657 28800
# Node ID bba9287641ff90e836d090d80b5c0a846aab7162
# Parent  d617b72a0cc9d14bde2087d065c36d4ed3265761
x86: page.h: move remaining bits and pieces

Move the remaining odds and ends into page.h.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

# HG changeset patch
# User Jeremy Fitzhardinge <jeremy@xensource.com>
# Date 1199319656 28800
# Node ID d617b72a0cc9d14bde2087d065c36d4ed3265761
# Parent  3bd7db6e85e66e7f3362874802df26a82fcb2d92
x86: page.h: move pa and va related things

Move and unify the virtual<->physical address space conversion
functions.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

based on:

 Subject: x86: page.h: move and unify types for pagetable entry
 From: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

# HG changeset patch
# User Jeremy Fitzhardinge <jeremy@xensource.com>
# Date 1199319654 28800
# Node ID 3bd7db6e85e66e7f3362874802df26a82fcb2d92
# Parent  f7e7db3facd9406545103164f9be8f9ba1a2b549
x86: page.h: move and unify types for pagetable entry definitions

This patch:

1. Defines arch-specific types for the contents of a pagetable entry.
That is, 32-bit entries for 32-bit non-PAE, and 64-bit entries for
32-bit PAE and 64-bit.  However, even though the latter two are the
same size, they're defined with different types in order to retain
compatibility with printk format strings, etc.

2. Defines arch-specific pte_t.  This is different because 32-bit PAE
defines it in two halves, whereas 32-bit PAE and 64-bit define it as a
single entry.  All the other pagetable levels can be defined in a
common way.  This also defines arch-specific pte_val/make_pte functions.

3. Define PAGETABLE_LEVELS for each architecture variation, for later use.

4. Define common pagetable entry accessors in a paravirt-compatible
way. (64-bit does not yet use paravirt-ops in any way).

5. Convert a few instances of using a *_val() as an lvalue where it is
no longer a macro.  There are still places in the 64-bit code which
use pte_val() as an lvalue.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

based on:

 Subject: x86: page.h: move and unify types for pagetable entry
 From: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

based on:

 Subject: x86: page.h: move and unify types for pagetable entry
 From: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

based on:

 Subject: x86: page.h: move and unify types for pagetable entry
 From: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

# HG changeset patch
# User Jeremy Fitzhardinge <jeremy@xensource.com>
# Date 1199317362 28800
# Node ID 4d9a413a0f4c1d98dbea704f0366457b5117045d
# Parent  ba0ec40a50a7aef1a3153cea124c35e261f5a2df
x86: page.h: unify page copying and clearing

Move, and to some extent unify, the various page copying and clearing
functions.  The only unification here is that both architectures use
the same function for copying/clearing user and kernel pages.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

# HG changeset patch
# User Jeremy Fitzhardinge <jeremy@xensource.com>
# Date 1199317360 28800
# Node ID ba0ec40a50a7aef1a3153cea124c35e261f5a2df
# Parent  c45c263179cb78284b6b869c574457df088027d1
x86: page.h: unify constants

There are many constants which are shared by 32 and 64-bit.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Move the headers to include/asm-x86 and fixup the
header install make rules
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>