'range_new' doesn't seem to be used after init. It is only passed
to memset(), sum_ranges(), memcmp() and x86_get_mtrr_mem_range(), the
latter of which also only passes it on to various *range*
library functions.

So mark it __initdata to free up an extra page after init.

Its contents are wiped at every call to mtrr_calc_range_state(),
so it being static is not about preserving state between calls,
but simply to avoid a 4k+ stack frame. While there, add a
comment explaining this and why it's safe.

We could also mark nr_range_new as __initdata, but since it's
just a single int and also doesn't carry state between calls (it
is unconditionally assigned to before it is read), we might as
well make it an ordinary automatic variable.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/1449002691-20783-1-git-send-email-linux@rasmusvillemoes.dkSigned-off-by: NIngo Molnar <mingo@kernel.org>

'mtrr_state.enabled' contains the FE (fixed MTRRs enabled)
and E (MTRRs enabled) flags in MSR_MTRRdefType.  Intel SDM,
section 11.11.2.1, defines these flags as follows:

 - All MTRRs are disabled when the E flag is clear.
   The FE flag has no affect when the E flag is clear.
 - The default type is enabled when the E flag is set.
 - MTRR variable ranges are enabled when the E flag is set.
 - MTRR fixed ranges are enabled when both E and FE flags
   are set.

MTRR state checks in __mtrr_type_lookup() do not match with SDM.

Hence, this patch makes the following changes:
 - The current code detects MTRRs disabled when both E and
   FE flags are clear in mtrr_state.enabled.  Fix to detect
   MTRRs disabled when the E flag is clear.
 - The current code does not check if the FE bit is set in
   mtrr_state.enabled when looking at the fixed entries.
   Fix to check the FE flag.
 - The current code returns the default type when the E flag
   is clear in mtrr_state.enabled. However, the default type
   is UC when the E flag is clear.  Remove the code as this
   case is handled as MTRR disabled with the 1st change.

In addition, this patch defines the E and FE flags in
mtrr_state.enabled as follows.
 - FE flag: MTRR_STATE_MTRR_FIXED_ENABLED
 - E  flag: MTRR_STATE_MTRR_ENABLED

print_mtrr_state() and x86_get_mtrr_mem_range() are also updated
accordingly.
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
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: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave.hansen@intel.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: pebolle@tiscali.nl
Link: http://lkml.kernel.org/r/1431714237-880-4-git-send-email-toshi.kani@hp.com
Link: http://lkml.kernel.org/r/1432628901-18044-4-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Joshua reported: Commit cd7b304dfaf1 (x86, range: fix missing merge
during add range) broke mtrr cleanup on his setup in 3.9.5.
corresponding commit in upstream is fbe06b7b.

  *BAD*gran_size: 64K chunk_size: 16M num_reg: 6 lose cover RAM: -0G

https://bugzilla.kernel.org/show_bug.cgi?id=59491

So it rejects new var mtrr layout.

It turns out we have some problem with initial mtrr range retrieval.
The current sequence is:
	x86_get_mtrr_mem_range
		==> bunchs of add_range_with_merge
		==> bunchs of subract_range
		==> clean_sort_range
	add_range_with_merge for [0,1M)
	sort_range()

add_range_with_merge could have blank slots, so we can not just
sort only, that will have final result have extra blank slot in head.

So move that calling add_range_with_merge for [0,1M), with that we
could avoid extra clean_sort_range calling.
Reported-by: NJoshua Covington <joshuacov@googlemail.com>
Tested-by: NJoshua Covington <joshuacov@googlemail.com>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1371154622-8929-2-git-send-email-yinghai@kernel.org
Cc: <stable@vger.kernel.org> v3.9
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

With the variable operated on being of "unsigned long" type,
neither ffs() nor fls() are suitable to use on them, as those
truncate their arguments to 32 bits. Using __ffs() and __fls()
respectively at once eliminates the need to subtract 1 from their
results.

Additionally, with the alignment value subsequently used as a
shift count, it must be enforced to be less than BITS_PER_LONG
(and on 64-bit there's no need for it to be any smaller).
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/4FF70D54020000780008E179@nat28.tlf.novell.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When boot on sun G5+ with 4T mem, see an overflow in mtrr cleanup as below.

*BAD*gran_size: 2G      chunk_size: 2G  num_reg: 10     lose cover RAM:
-18014398505283592M

This is because 1<<31 sign extended. Use an unsigned long constant to
fix it.  Useful for mem larger than or equal to 4T.

-v2: Use 64bit constant instead of explicit type conversion as suggested
by Yinghai. Description updated too.
Signed-off-by: NZhenzhong Duan <zhenzhong.duan@oracle.com>
Link: http://lkml.kernel.org/r/4FC5A77F.6060505@oracle.comSigned-off-by: NH. Peter Anvin <hpa@zytor.com>

Instead of adapting the CPU family check in amd_special_default_mtrr()
for each new CPU family assume that all new AMD CPUs support the
necessary bits in SYS_CFG MSR.

Tom2Enabled is architectural (defined in APM Vol.2).
Tom2ForceMemTypeWB is defined in all BKDGs starting with K8 NPT.
In pre K8-NPT BKDG this bit is reserved (read as zero).

W/o this adaption Linux would unnecessarily complain about bad MTRR
settings on every new AMD CPU family, e.g.

[    0.000000] WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 4863MB of RAM.

Cc: stable@kernel.org # .32.x, .35.x
Signed-off-by: NAndreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20100930123235.GB20545@loge.amd.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Also needed if pr_<level> becomes a bit more space efficient.
Signed-off-by: NJoe Perches <joe@perches.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
LKML-Reference: <1277768808.29157.280.camel@Joe-Laptop.home>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

So make interface more consistent with early_res.
Later we can share some code with early_res.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-10-git-send-email-yinghai@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

We have almost the same code for mtrr cleanup and amd_bus checkup, and
this code  will also be used in replacing bootmem with early_res,
so try to move them together and reuse it from different parts.

Also rename update_range to subtract_range as that is what the
function is actually doing.

-v2: update comments as Christoph requested
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-4-git-send-email-yinghai@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

In some cases we can coalesce MTRR entries after cleanup; this may
allow us to have more entries.  As such, introduce clean_sort_range to
to sort and coaelsce the MTRR entries.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <4B0BB9A3.5020908@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The current MTRR code treats WP as a form of UC.  This really isn't
desirable behaviour, except possibly in the case of severe MTRR
shortage.  Disable this, to allow legitimate uses of WP to remain
unmolested.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>

Trivial typo.
Signed-off-by: NDave Jones <davej@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Yinghai noticed that i defined BIOS_BUG_MSG but added no
usage for it. The usage is to clean up this turd in generic.c:

			printk(KERN_WARNING "WARNING: BIOS bug: VAR MTRR %d "
				"contains strange UC entry under 1M, check "
				"with your system vendor!\n", i);

Breaking printk lines in the middle looks ugly, is hard to read
and breaks 'git grep'. Use the BIOS_BUG_MSG instead.

Also complete the moving of structure definitions and variables
to the top of the file.
Reported-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <20090703164225.GA21447@elte.hu>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix trivial style problems:

  WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
  WARNING: Use #include <linux/kvm_para.h> instead of <asm/kvm_para.h>

Also, nr_mtrr_spare_reg should be unsigned long.

arch/x86/kernel/cpu/mtrr/cleanup.o:

   text	   data	    bss	    dec	    hex	filename
   6241	   8992	   2056	  17289	   4389	cleanup.o.before
   6241	   8992	   2056	  17289	   4389	cleanup.o.after

The md5 has changed:
   1a7a27513aef1825236daf29110fe657  cleanup.o.before.asm
   bcea358efa2532b6020e338e158447af  cleanup.o.after.asm

Because a WARN_ON()'s __LINE__ value changed by 3 lines.
Suggested-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20090703164225.GA21447@elte.hu>
[ Did lots of other cleanups to make the code look more consistent. ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use standard msr-index.h's MSR declaration and no need to declare again.

[ Impact: cleanup, no object code change ]
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/cpu/mtrr/cleanup.c:197: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘long unsigned int’
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1237378015.13488.1.camel@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: don't trim e820 according to wrong mtrr

Ozan reports that his server emits strange warning.
it turns out the BIOS sets the MTRRs incorrectly.

Ignore those strange ranges, and don't trim e820,
just emit one warning about BIOS
Reported-by: NOzan Çağlayan <ozan@pardus.org.tr>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <49BEE1E7.7020706@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

mtrr main.c is too big, seperate mtrr cleanup and mtrr e820 trim
code to another file.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <49B87C7B.80809@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: print more debug info

Keep it consistent with autodetect version.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <49B87C0A.4010105@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kerneloops.org is reporting a lot of these warnings that come due to
vmware not setting up any MTRRs for emulated CPUs:

| Reported 709 times (14696 total reports)
| BIOS bug (often in VMWare) where the MTRR's are set up incorrectly
| or not at all
|
| This warning was last seen in version 2.6.29-rc2-git1, and first
| seen in 2.6.24.
|
| More info:
|   http://www.kerneloops.org/searchweek.php?search=mtrr_trim_uncached_memory

Keep a one-liner KERN_INFO about it - so that we have so notice if empty
MTRRs are caused by native hardware/BIOS weirdness.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Prepare for exporting them.
Signed-off-by: NSheng Yang <sheng@linux.intel.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Impact: cleanup

enable_mtrr_cleanup is static, and is never set to anything but 0 or 1.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Ingo said mtrr_cleanup() is big and ugly.

so break it up into more functions and make it more readable.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

For the purpose of MTRR canonicalization, treat WRPROT as UNCACHEABLE.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The first 1M is don't care when it comes to the variables MTRRs.
Cover it as WB as a heuristic approximation; this is generally what we
want to minimize the number of registers.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Print out the correct type when the Write Protected (WP) type is seen.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

J.A. Magallón reported:

 >> Also, on a 64 bit box with 4Gb, it gives this:
 >>
 >> cicely:~# cat /proc/mtrr
 >> reg00: base=0x00000000 (   0MB), size=4096MB: write-back, count=1
 >> reg01: base=0x100000000 (4096MB), size=1024MB: write-back, count=1
 >> reg02: base=0x140000000 (5120MB), size= 512MB: write-back, count=1
 >> reg03: base=0x160000000 (5632MB), size= 256MB: write-back, count=1
 >> reg04: base=0x80000000 (2048MB), size=2048MB: uncachable, count=1

boundary handling has a problem ... fix it.
Reported-by: NJ.A. Magallón <jamagallon@ono.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Correct typo for 'enable_mtrr_cleanup' early boot param name.
Signed-off-by: NJ.A. Magallon <jamagallon@ono.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

one have gran < 1M

reg00: base=0xd8000000 (3456MB), size= 128MB: uncachable, count=1
reg01: base=0xe0000000 (3584MB), size= 512MB: uncachable, count=1
reg02: base=0x00000000 (   0MB), size=4096MB: write-back, count=1
reg03: base=0x100000000 (4096MB), size= 512MB: write-back, count=1
reg04: base=0x120000000 (4608MB), size= 128MB: write-back, count=1
reg05: base=0xd7f80000 (3455MB), size= 512KB: uncachable, count=1

will get

Found optimal setting for mtrr clean up
gran_size: 512K         chunk_size: 2M  num_reg: 7      lose RAM: 0G
range0: 0000000000000000 - 00000000d8000000
Setting variable MTRR 0, base: 0GB, range: 2GB, type WB
Setting variable MTRR 1, base: 2GB, range: 1GB, type WB
Setting variable MTRR 2, base: 3GB, range: 256MB, type WB
Setting variable MTRR 3, base: 3328MB, range: 128MB, type WB
hole: 00000000d7f00000 - 00000000d7f80000
Setting variable MTRR 4, base: 3455MB, range: 512KB, type UC
rangeX: 0000000100000000 - 0000000128000000
Setting variable MTRR 5, base: 4GB, range: 512MB, type WB
Setting variable MTRR 6, base: 4608MB, range: 128MB, type WB

so start from 64k instead of 1M
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

make the print out right with size < 1M
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Delay exit to make sure we can actually get the optimal result in as
many cases as possible.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

v2: should check with half of range0 size instead of chunk_size

So don't have silly big hole.

in hpa's case we could auto detect instead of adding mtrr_chunk_size in
command line.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

add mtrr_cleanup_debug to print out more info about layout
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

fix hpa's t61 with 4g ram:

   change layout from
	(n - 1)*chunksize + chunk_size - NC
   to
	n*chunksize - NC
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

change back chunksize max to 2g
   otherwise will get strange layout in 2G ram system like
     0 - 4g WB, 2040M - 2048M UC, 2048M -  4G NC
   instead of
     0 - 2g WB, 2040M - 2048M UC
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

fix this warning reported by Andrew Morton:

> arch/x86/kernel/cpu/mtrr/main.c: In function 'mtrr_bp_init':
> arch/x86/kernel/cpu/mtrr/main.c:1170: warning: 'extra_remove_base' may be used uninitialized in this function

the warning is bogus but the logic that prevents uninitialized use
is a bit convoluted so simplify it all.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use WARN() instead of a printk+WARN_ON() pair; this way the message
becomes part of the warning section for better reporting/collection.
This also allowed the folding of some if()'s into the WARN()
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Cc: akpm@linux-foundation.org
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NJaswinder Singh <jaswinder@infradead.org>

rename update_memory_range to e820_update_range
rename add_memory_region to e820_add_region

to make it more clear that they are about e820 map operations.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>