Commit Graph

34 Commits

Author SHA1 Message Date
Andi Kleen
fa10ba64ac x86, gcc-4.6: Fix set but not read variables
Just some dead code, no real bugs.

Found by gcc 4.6 -Wall

Signed-off-by: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <201007202219.o6KMJnQ0021072@imap1.linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-07-20 15:38:30 -07:00
Joerg Roedel
4b83873d3d x86/gart: Disable GART explicitly before initialization
If we boot into a crash-kernel the gart might still be
enabled and its caches might be dirty. This can result in
undefined behavior later. Fix it by explicitly disabling the
gart hardware before initialization and flushing the caches
after enablement.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
2010-04-07 14:36:30 +02:00
FUJITA Tomonori
c13f3d378f x86/gart: Unexport gart_iommu_aperture
I wrongly exported gart_iommu_aperture in the commit
42590a7501. It's not necessary so
let's unexport it.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Joerg Roedel <joerg.roedel@amd.com>
LKML-Reference: <20100215113241P.fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-16 22:05:09 +01:00
FUJITA Tomonori
42590a7501 x86/agp: Fix agp_amd64_init and agp_amd64_cleanup
This fixes the regression introduced by the commit
f405d2c023.

The above commit fixes the following issue:

  http://marc.info/?l=linux-kernel&m=126192729110083&w=2

However, it doesn't work properly when you remove and insert the
agp_amd64 module again.

agp_amd64_init() and agp_amd64_cleanup should be called only
when gart_iommu is not called earlier (that is, the GART IOMMU
is not enabled). We need to use 'gart_iommu_aperture' to see if
GART IOMMU is enabled or not.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: mitov@issp.bas.bg
Cc: davej@redhat.com
LKML-Reference: <20100104161603L.fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-13 11:15:37 +01:00
Yinghai Lu
f3eee54276 x86: Gart: fix breakage due to IOMMU initialization cleanup
This fixes the following breakage of the commit
75f1cdf1dd:

- GART systems that don't AGP with broken BIOS and more than 4GB
  memory are forced to use swiotlb. They can allocate aperture by
  hand and use GART.

- GART systems without GAP must disable GART on shutdown.

- swiotlb usage is forced by the boot option,
  gart_iommu_hole_init() is not called, so we disable GART
  early_gart_iommu_check().

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
LKML-Reference: <1260759135-6450-3-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-14 08:57:40 +01:00
FUJITA Tomonori
75f1cdf1dd x86: Handle HW IOMMU initialization failure gracefully
If HW IOMMU initialization fails (Intel VT-d often does this,
typically due to BIOS bugs), we fall back to nommu. It doesn't
work for the majority since nowadays we have more than 4GB
memory so we must use swiotlb instead of nommu.

The problem is that it's too late to initialize swiotlb when HW
IOMMU initialization fails. We need to allocate swiotlb memory
earlier from bootmem allocator. Chris explained the issue in
detail:

  http://marc.info/?l=linux-kernel&m=125657444317079&w=2

The current x86 IOMMU initialization sequence is too complicated
and handling the above issue makes it more hacky.

This patch changes x86 IOMMU initialization sequence to handle
the above issue cleanly.

The new x86 IOMMU initialization sequence are:

1. we initialize the swiotlb (and setting swiotlb to 1) in the case
   of (max_pfn > MAX_DMA32_PFN && !no_iommu). dma_ops is set to
   swiotlb_dma_ops or nommu_dma_ops. if swiotlb usage is forced by
   the boot option, we finish here.

2. we call the detection functions of all the IOMMUs

3. the detection function sets x86_init.iommu.iommu_init to the
   IOMMU initialization function (so we can avoid calling the
   initialization functions of all the IOMMUs needlessly).

4. if the IOMMU initialization function doesn't need to swiotlb
   then sets swiotlb to zero (e.g. the initialization is
   sucessful).

5. if we find that swiotlb is set to zero, we free swiotlb
   resource.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: chrisw@sous-sol.org
Cc: dwmw2@infradead.org
Cc: joerg.roedel@amd.com
Cc: muli@il.ibm.com
LKML-Reference: <1257849980-22640-10-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-10 12:32:07 +01:00
FUJITA Tomonori
de957628ce x86: GART: Convert gart_iommu_hole_init() to use iommu_init hook
This changes gart_iommu_hole_init() to set gart_iommu_init() to
iommu_init hook if gart_iommu_hole_init() finds the GART IOMMU.

We can kill the code to check if we found the IOMMU in
gart_iommu_init() since gart_iommu_hole_init() sets
gart_iommu_init() only when it found the IOMMU.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: chrisw@sous-sol.org
Cc: dwmw2@infradead.org
Cc: joerg.roedel@amd.com
Cc: muli@il.ibm.com
LKML-Reference: <1257849980-22640-4-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-10 12:31:23 +01:00
Catalin Marinas
acde31dc46 kmemleak: Ignore the aperture memory hole on x86_64
This block is allocated with alloc_bootmem() and scanned by kmemleak but
the kernel direct mapping may no longer exist. This patch tells kmemleak
to ignore this memory hole. The dma32_bootmem_ptr in
dma32_reserve_bootmem() is also ignored.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
2009-09-01 11:12:32 +01:00
Pavel Machek
8caac56305 aperture_64.c: clarify that too small aperture is valid reason for this code
Impact: update comment

Clarify that too small aperture is valid reason for this code.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-28 15:24:39 +01:00
Adam Jackson
9b1568458a x86, debug printouts: IOMMU setup failures should not be KERN_ERR
The number of BIOSes that have an option to enable the IOMMU, or fix
anything about its configuration, is vanishingly small.  There's no good
reason to punish quiet boot for this.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-30 10:25:28 +02:00
FUJITA Tomonori
46a7fa270a x86: make only GART code include gart.h
gart.h has only GART-specific stuff. Only GART code needs it. Other
IOMMU stuff should include iommu.h instead of gart.h.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-11 11:00:54 +02:00
Yinghai Lu
c987d12f84 x86: remove end_pfn in 64bit
and use max_pfn directly.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-08 13:10:38 +02:00
Ingo Molnar
3de352bbd8 Merge branch 'x86/mpparse' into x86/devel
Conflicts:

	arch/x86/Kconfig
	arch/x86/kernel/io_apic_32.c
	arch/x86/kernel/setup_64.c
	arch/x86/mm/init_32.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-08 11:14:58 +02:00
Yinghai Lu
d0be6bdea1 x86: rename two e820 related functions
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: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-08 10:37:01 +02:00
Yinghai Lu
0754557d72 x86: change early_gart_iommu_check() back to any_mapped
Kevin Winchester reported a GART related direct rendering failure against
linux-next-20080611, which shows up via these log entries:

 PCI: Using ACPI for IRQ routing
 PCI: Cannot allocate resource region 0 of device 0000:00:00.0
 agpgart: Detected AGP bridge 0
 agpgart: Aperture conflicts with PCI mapping.
 agpgart: Aperture from AGP @ e0000000 size 128 MB
 agpgart: Aperture conflicts with PCI mapping.
 agpgart: No usable aperture found.
 agpgart: Consider rebooting with iommu=memaper=2 to get a good aperture.

instead of the expected:

 PCI: Using ACPI for IRQ routing
 agpgart: Detected AGP bridge 0
 agpgart: Aperture from AGP @ e0000000 size 128 MB

Kevin bisected it down to this change in tip/x86/gart:
"x86: checking aperture size order".

agp check is using request_mem_region(), and could fail if e820 is reserved...

change it back to e820_any_mapped().

Reported-and-bisected-by: "Kevin Winchester" <kjwinchester@gmail.com>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Tested-by: Kevin Winchester <kjwinchester@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-23 13:12:04 +02:00
Rafael J. Wysocki
6703f6d10d x86, gart: add resume handling
If GART IOMMU is used on an AMD64 system, the northbridge registers
related to it should be restored during resume so that memory is not
corrupted.  Make gart_resume() handle that as appropriate.

Ref. http://lkml.org/lkml/2008/5/25/96 and the following thread.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-12 14:11:25 +02:00
Pavel Machek
4f384f8bcd x86: aperture_64.c: corner case wrong
If

fix == 0, aper_enabled == 1, gart_fix_e820 == 0

	if (!fix && !aper_enabled)
		return;

	if (gart_fix_e820 && !fix && aper_enabled) {
		if (e820_any_mapped(aper_base, aper_base + aper_size,
				    E820_RAM)) {
			/* reserve it, so we can reuse it in second kernel */
			printk(KERN_INFO "update e820 for GART\n");
			add_memory_region(aper_base, aper_size, E820_RESERVED);
			update_e820();
		}
		return;
	}

	/* different nodes have different setting, disable them all atfirst*/

we'll fall back here and disable all the settings, even when they were
all consistent.

What about this? (I hope it compiles...)

Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-06-05 13:59:13 +02:00
Pavel Machek
fa5b8a30cf aperture_64.c: duplicated code, buggy?
Hi!

void __init early_gart_iommu_check(void)

contains

	for (num = 24; num < 32; num++) {
		if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
			continue;

loop, with very similar loop duplicated in

void __init gart_iommu_hole_init(void)

. First copy of a loop seems to be buggy, too. It uses 0 as a "nothing
set" value, which may actually bite us in last_aper_enabled case
(because it may be often zero).

(Beware, it is hard to test this patch, because this code has about
2^8 different code paths, depending on hardware and cmdline settings).

Plus, the second loop does not check for consistency of
aper_enabled. Should it?

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-06-05 13:58:42 +02:00
Pavel Machek
dd564d0cf0 x86: aperture_64.c: cleanups
Some small cleanups for aperture_64.c; they should not really change
any code.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-27 18:03:56 +02:00
Pavel Machek
0abbc78a01 x86, aperture_64: use symbolic constants
Factor-out common aperture_valid code.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-22 11:35:14 +02:00
Yinghai Lu
55c0d721df x86: clean up aperture_64.c
1. use symbolic register names where appropriate.
2. num to bus or slot changing
3. handle for new opteron for bus other than 0

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-12 21:28:10 +02:00
Yinghai Lu
7677b2ef6c x86_64: allocate gart aperture from 512M
because we try to reserve dma32 early, so we have chance to get aperture
from 64M.

with some sequence aperture allocated from RAM, could become E820_RESERVED.

and then if doing a kexec with a big kernel that uncompressed size is above
64M we could have a range conflict with still using gart.

So allocate gart aperture from 512M instead.

Also change the fallback_aper_order to 5, because we don't have chance to get
2G or 4G aperture.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:28:10 +02:00
Yinghai Lu
8c9fd91a0d x86: checking aperture size order
some systems are using 32M for gart and agp when memory is less than 4G.
Kernel will reject and try to allcate another 64M that is not needed,
and we will waste 64M of perfectly good RAM.

this patch adds a workaround by checking aper_base/order between NB and
agp bridge. If they are the same, and memory size is less than 4G, it
will allow it.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:28:10 +02:00
Yinghai Lu
1edc1ab3f6 x86: agp_gart size checking for buggy device
while looking at Rafael J. Wysocki's system boot log,

I found a funny printout:

	Node 0: aperture @ de000000 size 32 MB
	Aperture too small (32 MB)
	AGP bridge at 00:04:00
	Aperture from AGP @ de000000 size 4096 MB (APSIZE 0)
	Aperture too small (0 MB)
	Your BIOS doesn't leave a aperture memory hole
	Please enable the IOMMU option in the BIOS setup
	This costs you 64 MB of RAM
	Mapping aperture over 65536 KB of RAM @ 4000000

	...

	agpgart: Detected AGP bridge 20
	agpgart: Aperture pointing to RAM
	agpgart: Aperture from AGP @ de000000 size 4096 MB
	agpgart: Aperture too small (0 MB)
	agpgart: No usable aperture found.
	agpgart: Consider rebooting with iommu=memaper=2 to get a good aperture.

it means BIOS allocated the correct gart on the NB and AGP bridge, but
because a bug in the silicon (the agp bridge reports the wrong order,
it wants 4G instead) the kernel will reject that allocation.

Also, because the size is only 32MB, and we try to get another 64M for gart,
late fix_northbridge can not revert that change because it still reads
the wrong size from agp bridge.

So try to double check the order value from the agp bridge, before calling
aperture_valid().

[ mingo@elte.hu: 32-bit fix. ]

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-12 21:28:10 +02:00
Pavel Machek
7de6a4cdac x86: clean up aperture_64.c
Initializing to zero is generally bad idea, I hope it is right for
__init data, too.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17 17:41:19 +02:00
Pavel Machek
2050d45d7c x86: fix long standing bug with usb after hibernation with 4GB ram
aperture_64.c takes a piece of memory and makes it into iommu
window... but such window may not be saved by swsusp -- that leads to
oops during hibernation.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-03-21 17:06:15 +01:00
Yinghai Lu
261a5ec36b x86: change aper valid checking sequence
old sequence:
  size ==> >4G  ==> point to RAM

changed to:
  >4G ==> point to RAM ==> size

some bios even leave aper to unclear, so check size at last.

To avoid reporting:

  Node 0: Aperture @ 4a42000000 size 32 MB
  Aperture too small (32 MB)

with this change we will get:

  Node 0: Aperture @ 4a42000000 size 32 MB
  Aperture beyond 4G. Ignoring.

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:39 +01:00
Yinghai Lu
47db4c3e93 x86: checking aperture report for node instead
currently when gart iommu is enabled by BIOS or previous we got

"
Checking aperture...
CPU 0: aperture @4000000 size 64MB
CPU 1: aperture @4000000 size 64MB
"
we should use use Node instead.

we will get
"
Checking aperture...
Node 0: aperture @4000000 size 64MB
Node 1: aperture @4000000 size 64MB
"

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:18 +01:00
Yinghai Lu
aaf2304242 x86: disable the GART early, 64-bit
For K8 system: 4G RAM with memory hole remapping enabled, or more than
4G RAM installed.

when try to use kexec second kernel, and the first doesn't include
gart_shutdown. the second kernel could have different aper position than
the first kernel. and second kernel could use that hole as RAM that is
still used by GART set by the first kernel. esp. when try to kexec
2.6.24 with sparse mem enable from previous kernel (from RHEL 5 or SLES
10). the new kernel will use aper by GART (set by first kernel) for
vmemmap. and after new kernel setting one new GART. the position will be
real RAM. the _mapcount set is lost.

Bad page state in process 'swapper'
page:ffffe2000e600020 flags:0x0000000000000000 mapping:0000000000000000 mapcount:1 count:0
Trying to fix it up, but a reboot is needed
Backtrace:
Pid: 0, comm: swapper Not tainted 2.6.24-rc7-smp-gcdf71a10-dirty #13

Call Trace:
 [<ffffffff8026401f>] bad_page+0x63/0x8d
 [<ffffffff80264169>] __free_pages_ok+0x7c/0x2a5
 [<ffffffff80ba75d1>] free_all_bootmem_core+0xd0/0x198
 [<ffffffff80ba3a42>] numa_free_all_bootmem+0x3b/0x76
 [<ffffffff80ba3461>] mem_init+0x3b/0x152
 [<ffffffff80b959d3>] start_kernel+0x236/0x2c2
 [<ffffffff80b9511a>] _sinittext+0x11a/0x121

and
 [ffffe2000e600000-ffffe2000e7fffff] PMD ->ffff81001c200000 on node 0
phys addr is : 0x1c200000

RHEL 5.1 kernel -53 said:
PCI-DMA: aperture base @ 1c000000 size 65536 KB

new kernel said:
Mapping aperture over 65536 KB of RAM @ 3c000000

So could try to disable that GART if possible.

According to Ingo

> hm, i'm wondering, instead of modifying the GART, why dont we simply
> _detect_ whatever GART settings we have inherited, and propagate that
> into our e820 maps? I.e. if there's inconsistency, then punch that out
> from the memory maps and just dont use that memory.
>
> that way it would not matter whether the GART settings came from a [old
> or crashing] Linux kernel that has not called gart_iommu_shutdown(), or
> whether it's a BIOS that has set up an aperture hole inconsistent with
> the memory map it passed. (or the memory map we _think_ i tried to pass
> us)
>
> it would also be more robust to only read and do a memory map quirk
> based on that, than actively trying to change the GART so early in the
> bootup. Later on we have to re-enable the GART _anyway_ and have to
> punch a hole for it.
>
> and as a bonus, we would have shored up our defenses against crappy
> BIOSes as well.

add e820 modification for gart inconsistent setting.

gart_fix_e820=off could be used to disable e820 fix.

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:09 +01:00
Ingo Molnar
31183ba8fd x86: clean up arch/x86/kernel/aperture_64.c printk()s
clean up arch/x86/kernel/aperture_64.c printk()s.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:30:10 +01:00
Ingo Molnar
c140df973c x86: clean up arch/x86/kernel/aperture_64.c
whitespace cleanup. No code changed:

   text    data     bss     dec     hex filename
   2080      76       4    2160     870 aperture_64.o.before
   2080      76       4    2160     870 aperture_64.o.after

                                       errors   lines of code   errors/KLOC
 arch/x86/kernel/aperture_64.c            114             299         381.2
 arch/x86/kernel/aperture_64.c              0             315             0

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:30:09 +01:00
Joerg Roedel
0440d4c00d x86 gart: rename symbols only used for the GART implementation
This patch renames the 4 symbols iommu_hole_init(), iommu_aperture,
iommu_aperture_allowed, iommu_aperture_disabled. All these symbols are only
used for the GART implementation of IOMMUs.

It adds and additional gart_ prefix to them.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-30 00:22:22 +01:00
Joerg Roedel
395624fcdd x86 gart: rename iommu.h to gart.h
This patch renames the include file asm-x86/iommu.h to asm-x86/gart.h to make
clear to which IOMMU implementation it belongs. The patch also adds "GART" to
the Kconfig line.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-30 00:22:22 +01:00
Thomas Gleixner
250c22777f x86_64: move kernel
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-11 11:17:24 +02:00