The firmware_has_feature() function makes it easy to check for supported
features of the hypervisor. This patch extends the capability of
firmware_has_feature() to include checking for specified bits
in vector 5 of the architecture vector as reported in the device tree.

As part of this the #defines used for the architecture vector are re-defined
such that each option has the index into vector 5 and the feature bit encoded
into it. This makes checking for architecture bits when initiating data
for firmware_has_feature much easier.
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

When iterating over the entries in firmware_features_table we only need
to go over the actual number of entries in the array instead of declaring
it to be bigger and checking to make sure there is a valid entry in every
slot.

This patch removes the FIRMWARE_MAX_FEATURES #define and replaces the
array looping with the use of ARRAY_SIZE().
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

As part of handling of PRRN events we need to check vector 5 of the
architecture vector bits reported in the device tree to ensure PRRN event
handling is enabled. To do this firmware_has_feature() is updated (in a
subsequent patch) to make this check vector 5 bits. To avoid having to
re-define bits in the architecture vector the bit definitions are moved
to prom.h.
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

A PRRN event is signaled via the RTAS event-scan mechanism, which
returns a Hot Plug Event message "fixed part" indicating "Platform
Resource Reassignment". In response to the Hot Plug Event message,
we must call ibm,update-nodes to determine which resources were
reassigned and then ibm,update-properties to obtain the new affinity
information about those resources.

The PRRN event-scan RTAS message contains only the "fixed part" with
the "Type" field set to the value 160 and no Extended Event Log. The
four-byte Extended Event Log Length field is re-purposed (since no
Extended Event Log message is included) to pass the "scope" parameter
that causes the ibm,update-nodes to return the nodes affected by the
specific resource reassignment.

This patch adds a handler for RTAS events. The function
pseries_devicetree_update() (from mobility.c) is used to make the
ibm,update-nodes/ibm,update-properties RTAS calls. Updating the NUMA maps
(handled by a subsequent patch) will require significant processing,
so pseries_devicetree_update() is called from an asynchronous workqueue
to allow event processing to continue.

PRRN RTAS events on pseries systems are rare events that have to be
initiated from the HMC console for the system by an IBM tech. This allows
us to assume that these events are widely spaced. Additionally, all work
on the queue is flushed before handling any new work to ensure we only have
one event in flight being handled at a time.
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Correct parsing of the buffer returned from ibm,update-properties. The first
element is a length and the path to the property which is slightly different
from the list of properties in the buffer so we need to specifically
handle this.
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Newer firmware on Power systems can transparently reassign platform resources
(CPU and Memory) in use. For instance, if a processor or memory unit is
predicted to fail, the platform may transparently move the processing to an
equivalent unused processor or the memory state to an equivalent unused
memory unit. However, reassigning resources across NUMA boundaries may alter
the performance of the partition. When such reassignment is necessary, the
Platform Resource Reassignment Notification (PRRN) option provides a
mechanism to inform the Linux kernel of changes to the NUMA affinity of
its platform resources.

When rtasd receives a PRRN event, it needs to make a series of RTAS
calls (ibm,update-nodes and ibm,update-properties) to retrieve the
updated device tree information. These calls are already handled in the
pseries_devicetree_update() routine used in partition migration.

This patch exposes pseries_devicetree_update() to make it accessible
to other pseries routines, this patch also updates pseries_devicetree_update()
to take a 32-bit scope parameter. The scope value, which was previously hard
coded to 1 for partition migration, is used for the RTAS calls
ibm,update-nodes/properties to update the device tree.
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

POWER8 allows us to take interrupts with the MMU on.  This gives us a
second set of vectors offset at 0x4000.

Unfortunately when coping these vectors we missed checking for MSR HV
for hardware interrupts (0x500).  This results in us trying to use
HSRR0/1 when HV=0, rather than SRR0/1 on HW IRQs

The below fixes this to check CPU_FTR_HVMODE when patching the code at
0x4500.

Also we remove the check for CPU_FTR_ARCH_206 since relocation on IRQs
are only available in arch 2.07 and beyond.

Thanks to benh for helping find this.
Signed-off-by: Michael Neuling <mikey@neuling.org>
CC: <stable@vger.kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

In __restore_cpu_power8 we determine if we are HV and if not, we return
before setting HV only resources.

Unfortunately we forgot to restore the link register from r11 before
returning.

This will happen on boot and with secondary CPUs not coming online.

This adds the missing link register restore.
Signed-off-by: Michael Neuling <mikey@neuling.org>
CC: <stable@vger.kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

In __after_prom_start we copy the kernel down to zero in two calls to
copy_and_flush.  After the first call (copy from 0 to copy_to_here:)
we jump to the newly copied code soon after.

Unfortunately there's no isync between the copy of this code and the
jump to it.  Hence it's possible that stale instructions could still be
in the icache or pipeline before we branch to it.

We've seen this on real machines and it's results in no console output
after:
  calling quiesce...
  returning from prom_init

The below adds an isync to ensure that the copy and flushing has
completed before any branching to the new instructions occurs.
Signed-off-by: Michael Neuling <mikey@neuling.org>
CC: <stable@vger.kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

We are currently out of free bits in AT_HWCAP. With POWER8, we have
several hardware features that we need to advertise.

Tested on POWER and x86.
Signed-off-by: Michael Neuling <michael@neuling.org>
Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

We need PPC_MSI_BITMAP support
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Merge upstream to get the audit fixes

In commit 85fe4025 (fs: do not assign default i_ino in new_inode), the
initialisation of i_ino was removed from new_inode() and pushed down
into the callers. However spufs_new_inode() was not updated.

This exhibits as no files appearing in /spu, because all our dirents
have a zero inode, which readdir() seems to dislike.

Cc: stable@vger.kernel.org
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Add new return code to rtas_flash to indicate firmware entitlement
expiry. Strictly we don't need this update. But to keep it in sync
with PAPR, this was added.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Add proper comment to ibm,validate-flash-image RTAS call
update result tokens.

Note: Only comment section is modified, no code change.
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

None of the cell platforms support CPU hotplug, so we should iterate
only over online nodes when setting PMU interrupts.

This also fixes a warning during boot when NODES_SHIFT is large enough:

WARNING: at /scratch/michael/src/kmk/linus/kernel/irq/irqdomain.c:766
...
NIP [c0000000000db278] .irq_linear_revmap+0x30/0x58
LR [c0000000000dc2a0] .irq_create_mapping+0x38/0x1a8
Call Trace:
[c0000003fc9c3af0] [c0000000000dc2a0] .irq_create_mapping+0x38/0x1a8 (unreliable)
[c0000003fc9c3b80] [c000000000655c1c] .__machine_initcall_cell_cbe_init_pm_irq+0x84/0x158
[c0000003fc9c3c20] [c00000000000afb4] .do_one_initcall+0x5c/0x1e0
[c0000003fc9c3cd0] [c000000000644580] .kernel_init_freeable+0x238/0x328
[c0000003fc9c3db0] [c00000000000b784] .kernel_init+0x1c/0x120
[c0000003fc9c3e30] [c000000000009fb8] .ret_from_kernel_thread+0x64/0xac

This is caused by us overflowing our linear revmap because we're
requesting too many interrupts.
Reported-by: Dennis Schridde <devurandom@gmx.net>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Merge the tentative powerpc-next branch maintained by Michael
while I was on vacation

need set '\0' for 'local_buffer'.

SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096. so the contents of
rtas_data_buf may truncated in memcpy.

if contents are really truncated.
  the splpar_strlen is more than 1026. the next while loop checking will
  not find the end of buffer. that will cause memory access violation.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch_dup_task_struct() does flush_ptrace_hw_breakpoint(src), this
destroys the parent's breakpoints for no reason. We should clear
child->thread.ptrace_bps[] copied by dup_task_struct() instead.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

On 04/18/2013 07:38 PM, Anton Blanchard wrote:
> Since you are only reading one long you shouldn't need to check the
> update count and loop, you will always see a consistent value. The
> system call version of time() just does an unprotected load for example.

Fixed.

> With the above change and with Michael's comments covered (decent
> changelog entry and Signed-off-by):
>
> Acked-by: Anton Blanchard <anton@samba.org>

Thanks for the review, below the updated patch:

From: Adhemerval Zanella <azanella@linux.vnet.ibm.com>

This patch implement the time syscall as vDSO. The performance speedups
are:

Baseline PPC32: 380 nsec
Baseline PPC64: 350 nsec
vdso PPC32:      20 nsec
vsdo PPC64:      20 nsec

Tested on 64 bit build with both 32 bit and 64 bit userland.
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Pull perf fixes from Ingo Molnar:
 "Misc fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Fix offcore_rsp valid mask for SNB/IVB
  perf: Treat attr.config as u64 in perf_swevent_init()

I'm going to do an -rc8, so I'm just going to do this rather than delay
it any further. They are arguably stable material anyway.

* vm_ioremap_memory-examples:
  mtdchar: remove no-longer-used vma helpers
  vm: convert snd_pcm_lib_mmap_iomem() to vm_iomap_memory() helper
  vm: convert fb_mmap to vm_iomap_memory() helper
  vm: convert mtdchar mmap to vm_iomap_memory() helper
  vm: convert HPET mmap to vm_iomap_memory() helper

Pull kdump fixes from Peter Anvin:
 "The kexec/kdump people have found several problems with the support
  for loading over 4 GiB that was introduced in this merge cycle.  This
  is partly due to a number of design problems inherent in the way the
  various pieces of kdump fit together (it is pretty horrifically manual
  in many places.)

  After a *lot* of iterations this is the patchset that was agreed upon,
  but of course it is now very late in the cycle.  However, because it
  changes both the syntax and semantics of the crashkernel option, it
  would be desirable to avoid a stable release with the broken
  interfaces."

I'm not happy with the timing, since originally the plan was to release
the final 3.9 tomorrow.  But apparently I'm doing an -rc8 instead...

* 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kexec: use Crash kernel for Crash kernel low
  x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low
  x86, kdump: Retore crashkernel= to allocate under 896M
  x86, kdump: Set crashkernel_low automatically

Pull x86 fixes from Peter Anvin:
 "Three groups of fixes:

   1. Make sure we don't execute the early microcode patching if family
      < 6, since it would touch MSRs which don't exist on those
      families, causing crashes.

   2. The Xen partial emulation of HyperV can be dealt with more
      gracefully than just disabling the driver.

   3. More EFI variable space magic.  In particular, variables hidden
      from runtime code need to be taken into account too."

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, microcode: Verify the family before dispatching microcode patching
  x86, hyperv: Handle Xen emulation of Hyper-V more gracefully
  x86,efi: Implement efi_no_storage_paranoia parameter
  efi: Export efi_query_variable_store() for efivars.ko
  x86/Kconfig: Make EFI select UCS2_STRING
  efi: Distinguish between "remaining space" and actually used space
  efi: Pass boot services variable info to runtime code
  Move utf16 functions to kernel core and rename
  x86,efi: Check max_size only if it is non-zero.
  x86, efivars: firmware bug workarounds should be in platform code

Pull ARM fixes from Russell King:
 "A set of fixes from various people - Will Deacon gets a prize for
  removing code this time around.  The biggest fix in this lot is
  sorting out the ARM740T mess.  The rest are relatively small fixes."

* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7699/1: sched_clock: Add more notrace to prevent recursion
  ARM: 7698/1: perf: fix group validation when using enable_on_exec
  ARM: 7697/1: hw_breakpoint: do not use __cpuinitdata for dbg_cpu_pm_nb
  ARM: 7696/1: Fix kexec by setting outer_cache.inv_all for Feroceon
  ARM: 7694/1: ARM, TCM: initialize TCM in paging_init(), instead of setup_arch()
  ARM: 7692/1: iop3xx: move IOP3XX_PERIPHERAL_VIRT_BASE
  ARM: modules: don't export cpu_set_pte_ext when !MMU
  ARM: mm: remove broken condition check for v4 flushing
  ARM: mm: fix numerous hideous errors in proc-arm740.S
  ARM: cache: remove ARMv3 support code
  ARM: tlbflush: remove ARMv3 support

Pull sparc fixes from David Miller:

 1) Fix race in sparc64 TLB shootdowns, we have to synchronize with the
    sibling cpus completing if we are passing them a reference via
    pointer to a data structure.

 2) Fix cleaning of bitmaps in sparc32, from Akinobu Mita.

 3) Fix various sparc header mistakes, some of which resulted in
    userland build breakage.  From Sam Ravnborg.

 4) Kill ghost declarations and defines missed when several bits of code
    got deleted recently.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: Fix race in TLB batch processing.
  sparc: use asm-generic version of types.h
  bbc_i2c: fix section mismatch warning
  sparc: use generic headers
  sparc:cleanup unused code in smp_32.h
  sparc/iommu: fix typo s/265KB/256KB/
  sparc/srmmu: clear trailing edge of bitmap properly
  sparc:remove unused declaration smp_boot_cpus()

Pull networking updates from David Miller:

 1) ax88796 does 64-bit divides which causes link errors on ARM, fix
    from Arnd Bergmann.

 2) Once an improper offload setting is detected on an SKB we don't rate
    limit the log message so we can very easily live lock.  From Ben
    Greear.

 3) Openvswitch cannot report vport configuration changes reliably
    because it didn't preallocate the netlink notification message
    before changing state.  From Jesse Gross.

 4) The effective UID/GID SCM credentials fix, from Linus.

 5) When a user explicitly asks for wireless authentication, cfg80211
    isn't told about the AP detachment leaving inconsistent state.  Fix
    from Johannes Berg.

 6) Fix self-MAC checks in batman-adv on multi-mesh nodes, from Antonio
    Quartulli.

 7) Revert build_skb() change sin IGB driver, can result in memory
    corruption.  From Alexander Duyck.

 8) Fix setting VLANs on virtual functions in IXGBE, from Greg Rose.

 9) Fix TSO races in qlcnic driver, from Sritej Velaga.

10) In bnx2x the kernel driver and UNDI firmware can try to program the
    chip at the same time, resulting in corruption.  Add proper
    synchronization.  From Dmitry Kravkov.

11) Fix corruption of status block in firmware ram in bxn2x, from Ariel
    Elior.

12) Fix load balancing hash regression of bonding driver in forwarding
    configurations, from Eric Dumazet.

13) Fix TS ECR regression in TCP by calling tcp_replace_ts_recent() in
    all the right spots, from Eric Dumazet.

14) Fix several bonding bugs having to do with address manintainence,
    including not removing address when configuration operations
    encounter errors, missed locking on the address lists, missing
    refcounting on VLAN objects, etc.  All from Nikolay Aleksandrov.

15) Add workarounds for firmware bugs in LTE qmi_wwan devices, wherein
    the devices fail to add a proper ethernet header while on LTE
    networks but otherwise properly do so on 2G and 3G ones.  From Bjørn
    Mork.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (38 commits)
  net: fix incorrect credentials passing
  net: rate-limit warn-bad-offload splats.
  net: ax88796: avoid 64 bit arithmetic
  qlge: Update version to 1.00.00.32.
  qlge: Fix ethtool autoneg advertising.
  qlge: Fix receive path to drop error frames
  net: qmi_wwan: prevent duplicate mac address on link (firmware bug workaround)
  net: qmi_wwan: fixup destination address (firmware bug workaround)
  net: qmi_wwan: fixup missing ethernet header (firmware bug workaround)
  bonding: in bond_mc_swap() bond's mc addr list is walked without lock
  bonding: disable netpoll on enslave failure
  bonding: primary_slave & curr_active_slave are not cleaned on enslave failure
  bonding: vlans don't get deleted on enslave failure
  bonding: mc addresses don't get deleted on enslave failure
  pkt_sched: fix error return code in fw_change_attrs()
  irda: small read past the end of array in debug code
  tcp: call tcp_replace_ts_recent() from tcp_ack()
  netfilter: xt_rpfilter: skip locally generated broadcast/multicast, too
  netfilter: ipset: bitmap:ip,mac: fix listing with timeout
  bonding: fix l23 and l34 load balancing in forwarding path
  ...

Commit 257b5358 ("scm: Capture the full credentials of the scm
sender") changed the credentials passing code to pass in the effective
uid/gid instead of the real uid/gid.

Obviously this doesn't matter most of the time (since normally they are
the same), but it results in differences for suid binaries when the wrong
uid/gid ends up being used.

This just undoes that (presumably unintentional) part of the commit.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Matt Fleming (1):
      x86, efivars: firmware bug workarounds should be in platform
      code

Matthew Garrett (3):
      Move utf16 functions to kernel core and rename
      efi: Pass boot services variable info to runtime code
      efi: Distinguish between "remaining space" and actually used
      space

Richard Weinberger (2):
      x86,efi: Check max_size only if it is non-zero.
      x86,efi: Implement efi_no_storage_paranoia parameter

Sergey Vlasov (2):
      x86/Kconfig: Make EFI select UCS2_STRING
      efi: Export efi_query_variable_store() for efivars.ko
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

For each CPU vendor that implements CPU microcode patching, there will
be a minimum family for which this is implemented.  Verify this
minimum level of support.

This can be done in the dispatch function or early in the application
functions.  Doing the latter turned out to be somewhat awkward because
of the ineviable split between the BSP and the AP paths, and rather
than pushing deep into the application functions, do this in
the dispatch function.
Reported-by: "Bryan O'Donoghue" <bryan.odonoghue.lkml@nexus-software.ie>
Suggested-by: Borislav Petkov <bp@alien8.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1366392183-4149-1-git-send-email-bryan.odonoghue.lkml@nexus-software.ie

If one does do something unfortunate and allow a
bad offload bug into the kernel, this the
skb_warn_bad_offload can effectively live-lock the
system, filling the logs with the same error over
and over.

Add rate limitation to this so that box remains otherwise
functional in this case.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When building ax88796 on an ARM platform with 64-bit resource_size_t,
we currently get

drivers/net/ethernet/8390/ax88796.c:875: undefined reference to `__aeabi_uldivmod'

because we do a division on the length of the MMIO resource.
Since we know that this resource is very short, using an
"unsigned long" instead of "resource_size_t" is entirely
sufficient, and avoids this link-time error.

Cc: Ben Dooks <ben-linux@fluff.org>
Cc: netdev@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Autoneg is supported on specific port types only. Fix the driver to advertise
autoneg based on the port type.
Signed-off-by: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

o Fix the driver to drop error frames in the receive path
o Update error counter which was not getting incremented
Signed-off-by: Sritej Velaga <sritej.velaga@qlogic.com>
Signed-off-by: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Bjørn Mork says:

====================
This series adds workarounds for 3 different firmware bugs, each
preventing the affected devices from working at all. I therefore
humbly request that these fixes go to stable-3.8 (if still
maintained) and 3.9 (either via net if still possible, or via
stable if not).

All 3 workarounds are applied to all devices supported by the driver.
Adding quirks for specific devices was considered as an alternative,
but was rejected because we have too little information about the
exact distribution of the buggy firmwares. All we know is that the
same bug shows up in devices from at least 3 different, and presumably
independent, vendors.

The workarounds have instead been designed to automatically apply
when necessary, and to have as little impact as possible on unaffected
devices.  The series has been tested on a number of devices both with
and without these bugs.

The series should apply cleanly to net/master, net-next/master and
stable/linux-3.8.y
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

We normally trust and use the CDC functional descriptors provided by a
number of devices.  But some of these will erroneously list the address
reserved for the device end of the link.  Attempting to use this on
both the device and host side will naturally not work.

Work around this bug by ignoring the functional descriptor and assign a
random address instead in this case.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

Received packets are sometimes addressed to 00:a0:c6:00:00:00
instead of the address the device firmware should have learned
from the host:

321.224126 77.16.85.204 -> 148.122.171.134 ICMP 98 Echo (ping) request  id=0x4025, seq=64/16384, ttl=64

0000  82 c0 82 c9 f1 67 82 c0 82 c9 f1 67 08 00 45 00   .....g.....g..E.
0010  00 54 00 00 40 00 40 01 57 cc 4d 10 55 cc 94 7a   .T..@.@.W.M.U..z
0020  ab 86 08 00 62 fc 40 25 00 40 b2 bc 6e 51 00 00   ....b.@%.@..nQ..
0030  00 00 6b bd 09 00 00 00 00 00 10 11 12 13 14 15   ..k.............
0040  16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25   .......... !"#$%
0050  26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35   &'()*+,-./012345
0060  36 37                                             67

321.240607 148.122.171.134 -> 77.16.85.204 ICMP 98 Echo (ping) reply    id=0x4025, seq=64/16384, ttl=55

0000  00 a0 c6 00 00 00 02 50 f3 00 00 00 08 00 45 00   .......P......E.
0010  00 54 00 56 00 00 37 01 a0 76 94 7a ab 86 4d 10   .T.V..7..v.z..M.
0020  55 cc 00 00 6a fc 40 25 00 40 b2 bc 6e 51 00 00   U...j.@%.@..nQ..
0030  00 00 6b bd 09 00 00 00 00 00 10 11 12 13 14 15   ..k.............
0040  16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25   .......... !"#$%
0050  26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35   &'()*+,-./012345
0060  36 37                                             67

The bogus address is always the same, and matches the address
suggested by many devices as a default address.  It is likely a
hardcoded firmware default.

The circumstances where this bug has been observed indicates that
the trigger is related to timing or some other factor the host
cannot control. Repeating the exact same configuration sequence
that caused it to trigger once, will not necessarily cause it to
trigger the next time. Reproducing the bug is therefore difficult.
This opens up a possibility that the bug is more common than we can
confirm, because affected devices often will work properly again
after a reset.  A procedure most users are likely to try out before
reporting a bug.

Unconditionally rewriting the destination address if the first digit
of the received packet is 0, is considered an acceptable compromise
since we already have to inspect this digit.  The simplification will
cause unnecessary rewrites if the real address starts with 0, but this
is still better than adding additional tests for this particular case.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>