Merge branch 'sched-docs-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-docs-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Document memory barriers implied by sleep/wake-up primitives

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: fix typo in sched-rt-group.txt file
  ftrace: fix typo about map of kernel priority in ftrace.txt file.
  sched: properly define the sched_group::cpumask and sched_domain::span fields
  sched, timers: cleanup avenrun users
  sched, timers: move calc_load() to scheduler
  sched: Don't export sched_mc_power_savings on multi-socket single core system
  sched: emit thread info flags with stack trace
  sched: rt: document the risk of small values in the bandwidth settings
  sched: Replace first_cpu() with cpumask_first() in ILB nomination code
  sched: remove extra call overhead for schedule()
  sched: use group_first_cpu() instead of cpumask_first(sched_group_cpus())
  wait: don't use __wake_up_common()
  sched: Nominate a power-efficient ilb in select_nohz_balancer()
  sched: Nominate idle load balancer from a semi-idle package.
  sched: remove redundant hierarchy walk in check_preempt_wakeup

Merge branch 'x86-kbuild-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-kbuild-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (46 commits)
  x86, boot: add new generated files to the appropriate .gitignore files
  x86, boot: correct the calculation of ZO_INIT_SIZE
  x86-64: align __PHYSICAL_START, remove __KERNEL_ALIGN
  x86, boot: correct sanity checks in boot/compressed/misc.c
  x86: add extension fields for bootloader type and version
  x86, defconfig: update kernel position parameters
  x86, defconfig: update to current, no material changes
  x86: make CONFIG_RELOCATABLE the default
  x86: default CONFIG_PHYSICAL_START and CONFIG_PHYSICAL_ALIGN to 16 MB
  x86: document new bzImage fields
  x86, boot: make kernel_alignment adjustable; new bzImage fields
  x86, boot: remove dead code from boot/compressed/head_*.S
  x86, boot: use LOAD_PHYSICAL_ADDR on 64 bits
  x86, boot: make symbols from the main vmlinux available
  x86, boot: determine compressed code offset at compile time
  x86, boot: use appropriate rep string for move and clear
  x86, boot: zero EFLAGS on 32 bits
  x86, boot: set up the decompression stack as early as possible
  x86, boot: straighten out ranges to copy/zero in compressed/head*.S
  x86, boot: stylistic cleanups for boot/compressed/head_64.S
  ...

Fixed trivial conflict in arch/x86/configs/x86_64_defconfig manually

* 'irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (76 commits)
  x86, apic: Fix dummy apic read operation together with broken MP handling
  x86, apic: Restore irqs on fail paths
  x86: Print real IOAPIC version for x86-64
  x86: enable_update_mptable should be a macro
  sparseirq: Allow early irq_desc allocation
  x86, io-apic: Don't mark pin_programmed early
  x86, irq: don't call mp_config_acpi_gsi() if update_mptable is not enabled
  x86, irq: update_mptable needs pci_routeirq
  x86: don't call read_apic_id if !cpu_has_apic
  x86, apic: introduce io_apic_irq_attr
  x86/pci: add 4 more return parameters to IO_APIC_get_PCI_irq_vector(), fix
  x86: read apic ID in the !acpi_lapic case
  x86: apic: Fixmap apic address even if apic disabled
  x86: display extended apic registers with print_local_APIC and cpu_debug code
  x86: read apic ID in the !acpi_lapic case
  x86: clean up and fix setup_clear/force_cpu_cap handling
  x86: apic: Check rev 3 fadt correctly for physical_apic bit
  x86/pci: update pirq_enable_irq() to setup io apic routing
  x86/acpi: move setup io apic routing out of CONFIG_ACPI scope
  x86/pci: add 4 more return parameters to IO_APIC_get_PCI_irq_vector()
  ...

The e_powersaver driver for VIA's C7 CPU's needs to be marked as
DANGEROUS as it configures the CPU to power states that are out
of specification.

According to Centaur, all systems with C7 and Nano CPU's support
the ACPI p-state method.  Thus, the acpi-cpufreq driver should
be used instead.
Signed-off-by: NHarald Welte <HaraldWelte@viatech.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The VIA/Centaur C7, C7-M and Nano CPU's all support ACPI based cpu p-states
using a MSR interface.  The Linux driver just never made use of it, since in
addition to the check for the EST flag it also checked if the vendor is Intel.
Signed-off-by: NHarald Welte <HaraldWelte@viatech.com>
[ Removed the vendor checks entirely  - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This helps with bad latencies for large reads from /dev/zero, but might
conceivably break some application that "knows" that a read of /dev/zero
cannot return early.  So do this early in the merge window to give us
maximal test coverage, even if the patch is totally trivial.

Obviously, no well-behaved application should ever depend on the read
being uninterruptible, but hey, bugs happen.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's a bug in the mxser kernel module that still appears in the
2.6.29.4 kernel.

mxser_get_ISA_conf takes a ioaddress as its first argument, by passing the
not of the ioaddr, you're effectively passing 0 which means it won't be
able to talk to an ISA card.  I have tested this, and removing the !
fixes the problem.

Cc: "Peter Botha" <peterb@goldcircle.co.za>
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Acked-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commit code, we scan buffers attached to a transaction.  During this
scan, we sometimes have to drop j_list_lock and then we recheck whether
the journal buffer head didn't get freed by journal_try_to_free_buffers().
 But checking for buffer_jbd(bh) isn't enough because a new journal head
could get attached to our buffer head.  So add a check whether the journal
head remained the same and whether it's still at the same transaction and
list.

This is a nasty bug and can cause problems like memory corruption (use after
free) or trigger various assertions in JBD code (observed).
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: <stable@kernel.org>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The recent ->lookup() deadlock correction required the directory inode
mutex to be dropped while waiting for expire completion.  We were
concerned about side effects from this change and one has been identified.

I saw several error messages.

They cause autofs to become quite confused and don't really point to the
actual problem.

Things like:

handle_packet_missing_direct:1376: can't find map entry for (43,1827932)

which is usually totally fatal (although in this case it wouldn't be
except that I treat is as such because it normally is).

do_mount_direct: direct trigger not valid or already mounted
/test/nested/g3c/s1/ss1

which is recoverable, however if this problem is at play it can cause
autofs to become quite confused as to the dependencies in the mount tree
because mount triggers end up mounted multiple times.  It's hard to
accurately check for this over mounting case and automount shouldn't need
to if the kernel module is doing its job.

There was one other message, similar in consequence of this last one but I
can't locate a log example just now.

When checking if a mount has already completed prior to adding a new mount
request to the wait queue we check if the dentry is hashed and, if so, if
it is a mount point.  But, if a mount successfully completed while we
slept on the wait queue mutex the dentry must exist for the mount to have
completed so the test is not really needed.

Mounts can also be done on top of a global root dentry, so for the above
case, where a mount request completes and the wait queue entry has already
been removed, the hashed test returning false can cause an incorrect
callback to the daemon.  Also, d_mountpoint() is not sufficient to check
if a mount has completed for the multi-mount case when we don't have a
real mount at the base of the tree.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The massive nommu update (8feae131) resulted in these warnings:
ipc/shm.c: In function `sys_shmdt':
ipc/shm.c:974: warning: unused variable `size'
ipc/shm.c:972: warning: unused variable `next'
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  kvm: fix kvm reboot crash when MAXSMP is used
  cpumask: alloc zeroed cpumask for static cpumask_var_ts
  cpumask: introduce zalloc_cpumask_var

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  bsg: setting rq->bio to NULL

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  cls_cgroup: Fix oops when user send improperly 'tc filter add' request
  r8169: fix crash when large packets are received

* 'for-linus' of git://neil.brown.name/md:
  md/raid5: fix bug in reshape code when chunk_size decreases.
  md/raid5 - avoid deadlocks in get_active_stripe during reshape
  md/raid5: use conf->raid_disks in preference to mddev->raid_disk

Due to commit 1cd96c24 ("block: WARN
in __blk_put_request() for potential bio leak"), BSG SMP requests get
the false warnings:

WARNING: at block/blk-core.c:1068 __blk_put_request+0x52/0xc0()

This sets rq->bio to NULL to avoid that false warnings.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

one system was found there is crash during reboot then kvm/MAXSMP
Sending all processes the KILL signal...                              done
Please stand by while rebooting the system...
[ 1721.856538] md: stopping all md devices.
[ 1722.852139] kvm: exiting hardware virtualization
[ 1722.854601] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 1722.872219] IP: [<ffffffff8102c6b6>] hardware_disable+0x4c/0xb4
[ 1722.877955] PGD 0
[ 1722.880042] Oops: 0000 [#1] SMP
[ 1722.892548] last sysfs file: /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/host0/target0:2:0/0:2:0:0/vendor
[ 1722.900977] CPU 9
[ 1722.912606] Modules linked in:
[ 1722.914226] Pid: 0, comm: swapper Not tainted 2.6.30-rc7-tip-01843-g2305324-dirty #299 ...
[ 1722.932589] RIP: 0010:[<ffffffff8102c6b6>]  [<ffffffff8102c6b6>] hardware_disable+0x4c/0xb4
[ 1722.942709] RSP: 0018:ffffc900010b6ed8  EFLAGS: 00010046
[ 1722.956121] RAX: 0000000000000000 RBX: ffffc9000e253140 RCX: 0000000000000009
[ 1722.972202] RDX: 000000000000b020 RSI: ffffc900010c3220 RDI: ffffffffffffd790
[ 1722.977399] RBP: ffffc900010b6f08 R08: 0000000000000000 R09: 0000000000000000
[ 1722.995149] R10: 00000000000004b8 R11: 966912b6c78fddbd R12: 0000000000000009
[ 1723.011551] R13: 000000000000b020 R14: 0000000000000009 R15: 0000000000000000
[ 1723.019898] FS:  0000000000000000(0000) GS:ffffc900010b3000(0000) knlGS:0000000000000000
[ 1723.034389] CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
[ 1723.041164] CR2: 0000000000000000 CR3: 0000000001001000 CR4: 00000000000006e0
[ 1723.056192] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1723.072546] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 1723.080562] Process swapper (pid: 0, threadinfo ffff88107e464000, task ffff88047e5a2550)
[ 1723.096144] Stack:
[ 1723.099071]  0000000000000046 ffffc9000e253168 966912b6c78fddbd ffffc9000e253140
[ 1723.115471]  ffff880c7d4304d0 ffffc9000e253168 ffffc900010b6f28 ffffffff81011022
[ 1723.132428]  ffffc900010b6f48 966912b6c78fddbd ffffc900010b6f48 ffffffff8100b83b
[ 1723.141973] Call Trace:
[ 1723.142981]  <IRQ> <0> [<ffffffff81011022>] kvm_arch_hardware_disable+0x26/0x3c
[ 1723.158153]  [<ffffffff8100b83b>] hardware_disable+0x3f/0x55
[ 1723.172168]  [<ffffffff810b95f6>] generic_smp_call_function_interrupt+0x76/0x13c
[ 1723.178836]  [<ffffffff8104cbea>] smp_call_function_interrupt+0x3a/0x5e
[ 1723.194689]  [<ffffffff81035bf3>] call_function_interrupt+0x13/0x20
[ 1723.199750]  <EOI> <0> [<ffffffff814ad3b4>] ? acpi_idle_enter_c1+0xd3/0xf4
[ 1723.217508]  [<ffffffff814ad3ae>] ? acpi_idle_enter_c1+0xcd/0xf4
[ 1723.232172]  [<ffffffff814ad4bc>] ? acpi_idle_enter_bm+0xe7/0x2ce
[ 1723.235141]  [<ffffffff81a8d93f>] ? __atomic_notifier_call_chain+0x0/0xac
[ 1723.253381]  [<ffffffff818c3dff>] ? menu_select+0x58/0xd2
[ 1723.258179]  [<ffffffff818c2c9d>] ? cpuidle_idle_call+0xa4/0xf3
[ 1723.272828]  [<ffffffff81034085>] ? cpu_idle+0xb8/0x101
[ 1723.277085]  [<ffffffff81a80163>] ? start_secondary+0x1bc/0x1d7
[ 1723.293708] Code: b0 00 00 65 48 8b 04 25 28 00 00 00 48 89 45 e0 31 c0 48 8b 04 cd 30 ee 27 82 49 89 cc 49 89 d5 48 8b 04 10 48 8d b8 90 d7 ff ff <48> 8b 87 70 28 00 00 48 8d 98 90 d7 ff ff eb 16 e8 e9 fe ff ff
[ 1723.335524] RIP  [<ffffffff8102c6b6>] hardware_disable+0x4c/0xb4
[ 1723.342076]  RSP <ffffc900010b6ed8>
[ 1723.352021] CR2: 0000000000000000
[ 1723.354348] ---[ end trace e2aec53dae150aa1 ]---

it turns out that we need clear cpus_hardware_enabled in that case.
Reported-and-tested-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

These are defined as static cpumask_var_t so if MAXSMP is not used,
they are cleared already.  Avoid surprises when MAXSMP is enabled.
Signed-off-by: NYinghai Lu <yinghai.lu@kernel.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

So can get cpumask_var with cpumask_clear
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

I found a bug in cls_cgroup_change() in cls_cgroup.c.
cls_cgroup_change() expected tca[TCA_OPTIONS] was set from user space properly,
but tc in iproute2-2.6.29-1 (which I used) didn't set it.

In the current source code of tc in git, it set tca[TCA_OPTIONS].

  git://git.kernel.org/pub/scm/linux/kernel/git/shemminger/iproute2.git

If we always use a newest iproute2 in git when we use cls_cgroup, 
we don't face this oops probably.
But I think, kernel shouldn't panic regardless of use program's behaviour. 
Signed-off-by: NMinoru Usui <usui@mxm.nes.nec.co.jp>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Michael Tokarev reported receiving a large packet could crash
a machine with RTL8169 NIC.
( original thread at http://lkml.org/lkml/2009/6/8/192 )

Problem is this driver tells that NIC frames up to 16383 bytes
can be received but provides skb to rx ring allocated with
smaller sizes (1536 bytes in case standard 1500 bytes MTU is used)

When a frame larger than what was allocated by driver is received,
dma transfert can occurs past the end of buffer and corrupt
kernel memory.

Fix is to tell to NIC what is the maximum size a frame can be.

This bug is very old, (before git introduction, linux-2.6.10), and 
should be backported to stable versions.
Reported-by: NMichael Tokarev <mjt@tls.msk.ru>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Tested-by: NMichael Tokarev <mjt@tls.msk.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that we support changing the chunksize, we calculate
"reshape_sectors" to be the max of number of sectors in old
and new chunk size.
However there is one please where we still use 'chunksize'
rather than 'reshape_sectors'.
This causes a reshape that reduces the size of chunks to freeze.
Signed-off-by: NNeilBrown <neilb@suse.de>

md has functionality to 'quiesce' and array so that all pending
IO completed and no new IO starts.  This is used to achieve a
stable state before making internal changes.

Currently this quiescing applies equally to normal IO, resync
IO, and reshape IO.
However there is a problem with applying it to reshape IO.
Reshape can have multiple 'stripe_heads' that must be active together.
If the quiesce come between allocating the first and the last of
such a collection, then we deadlock, as the last will not be allocated
until the quiesce is lifted, the quiesce will not be lifted until the
first (which has been allocated) gets used, and that first cannot be
used until the last is allocated.

It is not necessary to inhibit reshape IO when a quiesce is
requested.  Those places in the code that require a full quiesce will
ensure the reshape thread is not running at all.

So allow reshape requests to get access to new stripe_heads without
being blocked by a 'quiesce'.

This only affects in-place reshapes (i.e. where the array does not
grow or shrink) and these are only newly supported.  So this patch is
not needed in earlier kernels.
Signed-off-by: NNeilBrown <neilb@suse.de>

mddev->raid_disks can be changed and any time by a request from
user-space.  It is a suggestion as to what number of raid_disks is
desired.

conf->raid_disks can only be changed by the raid5 module with suitable
locks in place.  It is a statement as to the current number of
raid_disks.

There are two places where the latter should be used, but the former
is used.  This can lead to a crash when reshaping an array.

This patch changes to mddev-> to conf->
Signed-off-by: NNeilBrown <neilb@suse.de>

Our async work synchronization was broken by "async: make sure
independent async domains can't accidentally entangle" (commit
d5a877e8), because it would report
the wrong lowest active async ID when there was both running and
pending async work.

This caused things like no being able to read the root filesystem,
resulting in missing console devices and inability to run 'init',
causing a boot-time panic.

This fixes it by properly returning the lowest pending async ID: if
there is any running async work, that will have a lower ID than any
pending work, and we should _not_ look at the pending work list.

There were alternative patches from Jaswinder and James, but this one
also cleans up the code by removing the pointless 'ret' variable and
the unnecesary testing for an empty list around 'for_each_entry()' (if
the list is empty, the for_each_entry() thing just won't execute).

Fixes-bug: http://bugzilla.kernel.org/show_bug.cgi?id=13474Reported-and-tested-by: NChris Clayton <chris2553@googlemail.com>
Cc: Jaswinder Singh Rajput <jaswinder@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
  MIPS: Outline udelay and fix a few issues.
  MIPS: ioctl.h: Fix headers_check warnings
  MIPS: Cobalt: PCI bus is always required to obtain the board ID
  MIPS: Kconfig: Remove "Support for" from Cavium system type
  MIPS: Sibyte: Honor CONFIG_CMDLINE
  SSB: BCM47xx: Export ssb_watchdog_timer_set

The previous patch submission had a I typo I didn't catch but Bartlomiej
noted. Guess this proves the point about any patch being risky late in an rc
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'kvm-updates/2.6.30' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: Explicity initialize cpus_hardware_enabled

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6:
  pdc202xx_old: fix resetproc() method
  pdc202xx_old: fix 'pdc20246_dma_ops'

Outlining fixes the issue were on certain CPUs such as the R10000 family
the delay loop would need an extra cycle if it overlaps a cacheline
boundary.

The rewrite also fixes build errors with GCC 4.4 which was changed in
way incompatible with the kernel's inline assembly.

Relying on pure C for computation of the delay value removes the need for
explicit.  The price we pay is a slight slowdown of the computation - to
be fixed on another day.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Make ioctl.h compatible with asm-generic/ioctl.h and userspace

fix the following 'make headers_check' warning:

  usr/include/asm-mips/ioctl.h:64: extern's make no sense in userspace
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NYoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NYoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Acked-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Original patch by Imre Kaloz <kaloz@openwrt.org>.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

this patch export ssb_watchdog_timer_set to allow to use it in a Linux 
watchdog driver.
Signed-off-by: NMatthieu CASTET <castet.matthieu@free.fr>
Acked-by : Michael Buesch <mb@bu3sch.de>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

* master.kernel.org:/home/rmk/linux-2.6-arm:
  [ARM] 5543/1: arm: serial amba: add missing declaration in serial.h
  [ARM] pxa: fix pxa27x_udc default pullup GPIO
  [ARM] pxa/imote2: fix UCAM sensor board ADC model number
  mx[23]: don't put clock lookups in __initdata
  fix oops when using console=ttymxcN with N > 0
  [ARM] ARMv7 errata: only apply fixes when running on applicable CPU
  [ARM] 5534/1: kmalloc must return a cache line aligned buffer

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/drzeus/mmc:
  sdhci-of: Fix the wrong accessor to HOSTVER register
  mvsdio: fix config failure with some high speed SDHC cards
  mvsdio: ignore high speed timing requests from the core
  mmc/omap: Use disable_irq_nosync() from within irq handlers.
  sdhci-of: Add fsl,esdhc as a valid compatible to bind against
  mvsdio: allow automatic loading when modular
  mxcmmc: Fix missing return value checking in DMA setup code.
  mxcmmc : Reset the SDHC hardware if software timeout occurs.
  omap_hsmmc: Trivial fix for a typo in comment
  mxcmmc: decrease minimum frequency to make MMC cards work

Under CONFIG_MAXSMP, cpus_hardware_enabled is allocated from the heap and
not statically initialized.  This causes a crash on reboot when kvm thinks
vmx is enabled on random nonexistent cpus and accesses nonexistent percpu
lists.

Fix by explicitly clearing the variable.

Cc: stable@kernel.org
Reported-and-tested-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NAvi Kivity <avi@redhat.com>

This header is sometimes included in the uncompress stage to get
register values, but no <linux/amba/bus.h> can be included there.
So declare "struct amba_device" here before using it in a prototype.
Signed-off-by: NAlessandro Rubini <rubini@unipv.it>
Acked-by: NAndrea Gallo <andrea.gallo@stericsson.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>