Based on draft-ietf-nfsv4-scsi-layout-05 after the WG last call.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

sunrpc_cache_pipe_upcall() can detect a race if CACHE_PENDING is no longer
set.  In this case it aborts the queuing of the upcall.
However it has already taken a new counted reference on "h" and
doesn't "put" it, even though it frees the data structure holding the reference.

So let's delay the "cache_get" until we know we need it.

Fixes: f9e1aedc ("sunrpc/cache: remove races with queuing an upcall.")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

nfsd4_cltrack_grace_start() will allocate the memory for grace_start but
when we returned due to error we missed freeing it.
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

nfsd_lookup_dentry exits with the parent filehandle locked.  fh_put also
unlocks if necessary (nfsd filehandle locking is probably too lenient),
so it gets unlocked eventually, but if the following op in the compound
needs to lock it again, we can deadlock.

A fuzzer ran into this; normal clients don't send a secinfo followed by
a readdir in the same compound.

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Calling ib_poll_cq() to sort through WCs during a completion is a
common pattern amongst RDMA consumers. Since commit 14d3a3b2
("IB: add a proper completion queue abstraction"), WC sorting can
be handled by the IB core.

By converting to this new API, svcrdma is made a better neighbor to
other RDMA consumers, as it allows the core to schedule the delivery
of completions more fairly amongst all active consumers.

This new API also aims each completion at a function that is
specific to the WR's opcode. Thus the ctxt->wr_op field and the
switch in process_context is replaced by a set of methods that
handle each completion type.

Because each ib_cqe carries a pointer to a completion method, the
core can now post operations on a consumer's QP, and handle the
completions itself.

The server's rdma_stat_sq_poll and rdma_stat_sq_prod metrics are no
longer updated.

As a clean up, the cq_event_handler, the dto_tasklet, and all
associated locking is removed, as they are no longer referenced or
used.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Calling ib_poll_cq() to sort through WCs during a completion is a
common pattern amongst RDMA consumers. Since commit 14d3a3b2
("IB: add a proper completion queue abstraction"), WC sorting can
be handled by the IB core.

By converting to this new API, svcrdma is made a better neighbor to
other RDMA consumers, as it allows the core to schedule the delivery
of completions more fairly amongst all active consumers.

Because each ib_cqe carries a pointer to a completion method, the
core can now post operations on a consumer's QP, and handle the
completions itself.

svcrdma receive completions no longer use the dto_tasklet. Each
polled Receive WC is now handled individually in soft IRQ context.

The server transport's rdma_stat_rq_poll and rdma_stat_rq_prod
metrics are no longer updated.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Clean up: close_out is reached only when ctxt == NULL and XPT_CLOSE
is already set.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Tested-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

RFC 5666 Section 4.2 states:

> When the peer detects an RPC-over-RDMA header version that it does
> not support (currently this document defines only version 1), it
> replies with an error code of ERR_VERS, and provides the low and
> high inclusive version numbers it does, in fact, support.

And:

> When other decoding errors are detected in the header or chunks,
> either an RPC decode error MAY be returned or the RPC/RDMA error
> code ERR_CHUNK MUST be returned.

The Linux NFS server does throw ERR_VERS when a client sends it
a request whose rdma_version is not "one." But it does not return
ERR_CHUNK when a header decoding error occurs. It just drops the
request.

To improve protocol extensibility, it should reject invalid values
in the rdma_proc field instead of treating them all like RDMA_MSG.
Otherwise clients can't detect when the server doesn't support
new rdma_proc values.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Tested-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

When constructing an error reply, svc_rdma_xdr_encode_error()
needs to view the client's request message so it can get the
failing request's XID.

svc_rdma_xdr_decode_req() is supposed to return a pointer to the
client's request header. But if it fails to decode the client's
message (and thus an error reply is needed) it does not return the
pointer. The server then sends a bogus XID in the error reply.

Instead, unconditionally generate the pointer to the client's header
in svc_rdma_recvfrom(), and pass that pointer to both functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Tested-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Fix several issues with svc_rdma_send_error():

 - Post a receive buffer to replace the one that was consumed by
   the incoming request
 - Posting a send should use DMA_TO_DEVICE, not DMA_FROM_DEVICE
 - No need to put_page _and_ free pages in svc_rdma_put_context
 - Make sure the sge is set up completely in case the error
   path goes through svc_rdma_unmap_dma()
 - Replace the use of ENOSYS, which has a reserved meaning

Related fixes in svc_rdma_recvfrom():

 - Don't leak the ctxt associated with the incoming request
 - Don't close the connection after sending an error reply
 - Let svc_rdma_send_error() figure out the right header error code

As a last clean up, move svc_rdma_send_error() to svc_rdma_sendto.c
with other similar functions. There is some common logic in these
functions that could someday be combined to reduce code duplication.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Tested-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Error headers are shorter than either RDMA_MSG or RDMA_NOMSG.

Since HDRLEN_MIN is already used in several other places that would
be annoying to change, add RPCRDMA_HDRLEN_ERR for the one or two
spots where the shorter length is needed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Clean up: Most svc_rdma_post_recv() call sites close the transport
connection when a receive cannot be posted. Wrap that in a common
helper.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Tested-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The maximum size of a backchannel message on RPC-over-RDMA depends
on the connection's inline threshold. Today that threshold is
typically 1024 bytes, making the maximum message size 996 bytes.

The Linux server's CREATE_SESSION operation checks that the size
of callback Calls can be as large as 1044 bytes, to accommodate
RPCSEC_GSS. Thus CREATE_SESSION fails if a client advertises the
true message size maximum of 996 bytes.

But the server's backchannel currently does not support RPCSEC_GSS.
The actual maximum size it needs is much smaller. It is safe to
reduce the limit to enable NFSv4.1 on RDMA backchannel operation.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The NFS server's XDR encoders adds an XDR pad for content in the
xdr_buf page list at the beginning of the xdr_buf's tail buffer.

On RDMA transports, Write chunks are sent separately and without an
XDR pad.

If a Write chunk is being sent, strip off the pad in the tail buffer
so that inline content following the Write chunk remains XDR-aligned
when it is sent to the client.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=294Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

When the Linux NFS server writes an odd-length data item into a
Write chunk, it finishes with XDR pad bytes. If the data item is
smaller than the Write chunk, the pad bytes are written at the end
of the data item, but still inside the chunk (ie, in the
application's buffer). Since this is direct data placement, that
exposes the pad bytes.

XDR pad bytes are inserted in order to preserve the XDR alignment
of the next XDR data item in an XDR stream. But Write chunks do not
appear in the payload XDR stream, and only one data item is allowed
in each chunk. Thus XDR padding is not needed in a Write chunk.

With NFSv4, the Linux NFS server places the results of any
operations that follow an NFSv4 READ or READLINK in the xdr_buf's
tail. Those results also should never be sent as a part of a Write
chunk. The current logic in send_write_chunks() appears to assume
that the xdr_buf's tail contains only pad bytes (ie, NFSv3).

The server should write only the contents of the xdr_buf's page list
in a Write chunk. If there's more than an XDR pad in the tail, that
needs to go inline or in the Reply chunk.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=294Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The client provides the location of Write chunks into which the
server writes bulk payload. The client provides these when the
Upper Layer Protocol wants direct data placement and the Binding
allows it. (For NFS, this is READ and READLINK operations).

The client also provides the location of a Reply chunk into which
the server writes the non-bulk part of an RPC reply. The client
provides this chunk whenever it believes the reply can be larger
than its receive buffers.

The server then uses the presence of these chunks to determine how
it will form its reply message.

svc_rdma_sendto() was looking for Write and Reply chunks multiple
times for every reply message. It would be more efficient to do it
just once.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The server does indeed now support NFSv4.1 on RDMA transports. It
does not support shifting an RDMA-capable TCP transport (such as
iWARP) to RDMA mode.
Reported-by: Shirley Ma <shirley.ma@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Remember free allocated client when meeting unsupported state protect how.

Fixes: 50c7b948 ("nfsd: minor consolidation of mach_cred handling code")
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

A number of spots in the xdr decoding follow a pattern like

	n = be32_to_cpup(p++);
	READ_BUF(n + 4);

where n is a u32.  The only bounds checking is done in READ_BUF itself,
but since it's checking (n + 4), it won't catch cases where n is very
large, (u32)(-4) or higher.  I'm not sure exactly what the consequences
are, but we've seen crashes soon after.

Instead, just break these up into two READ_BUF()s.

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The qword_get() function NUL-terminates its output buffer.  If the input
string is in hex format \xXXXX... and the same length as the output
buffer, there is an off-by-one:

  int qword_get(char **bpp, char *dest, int bufsize)
  {
      ...
      while (len < bufsize) {
          ...
          *dest++ = (h << 4) | l;
          len++;
      }
      ...
      *dest = '\0';
      return len;
  }

This patch ensures the NUL terminator doesn't fall outside the output
buffer.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Pull char/misc driver fixes from Greg KH:
 "Here are 3 fixes for some reported issues.  Two nvmem driver fixes,
  and one mei fix.  All have been in linux-next just fine"

* tag 'char-misc-4.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  nvmem: qfprom: Specify LE device endianness
  nvmem: core: return error for non word aligned access
  mei: validate request value in client notify request ioctl

Pull driver core fix from Greg KH:
 "Here is one driver core, well klist, fix for 4.5-rc4.

  It fixes a problem found in the scsi device list traversal that
  probably also could be triggered by other subsystems.

  The fix has been in linux-next for a while with no reported problems"

* tag 'driver-core-4.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  klist: fix starting point removed bug in klist iterators

Pull tty/serial fixes from Greg KH:
 "Here are a number of small tty and serial driver fixes for 4.5-rc4
  that resolve some reported issues.

  One of them got reverted as it wasn't correct based on testing, and
  all have been in linux-next for a while"

* tag 'tty-4.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  Revert "8250: uniphier: allow modular build with 8250 console"
  pty: make sure super_block is still valid in final /dev/tty close
  pty: fix possible use after free of tty->driver_data
  tty: Add support for PCIe WCH382 2S multi-IO card
  serial/omap: mark wait_for_xmitr as __maybe_unused
  serial: omap: Prevent DoS using unprivileged ioctl(TIOCSRS485)
  8250: uniphier: allow modular build with 8250 console
  tty: Drop krefs for interrupted tty lock

Pull PHY fixes from Greg KH:
 "Here are a couple of PHY driver fixes for 4.5-rc4.

  A few small phy issues.  All have been in linux-next with no reported
  issues"

* tag 'usb-4.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  phy: twl4030-usb: Fix unbalanced pm_runtime_enable on module reload
  phy: twl4030-usb: Relase usb phy on unload
  phy: core: fix wrong err handle for phy_power_on
  phy: Restrict phy-hi6220-usb to HiSilicon arm64

Pull perf tooling fixes from Thomas Gleixner:
 "Another round of fixes for the perf tooling side:

   - Prevent a NULL pointer dereference in tracepoint error handling

   - Fix a thread handling bug in the intel_pt error handling code

   - Search both .eh_frame and .debug_frame sections as toolchains seem
     to have random choices of storing the CFI information

   - Fix the perf state interval output values, which got broken when
     fixing the overall output"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf stat: Fix interval output values
  perf probe: Search both .eh_frame and .debug_frame sections for probe location
  perf tools: Fix thread lifetime related segfaut in intel_pt
  perf tools: tracepoint_error() can receive e=NULL, robustify it

Pull lockdep fix from Thomas Gleixner:
 "A single fix for the stack trace caching logic in lockdep, where the
  duplicate avoidance managed to store no back trace at all"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Fix stack trace caching logic

Pull timer fix from Thomas Gleixner:
 "A single fix preventing a 32bit overflow in timespec/val to cputime
  conversions on 32bit machines"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cputime: Prevent 32bit overflow in time[val|spec]_to_cputime()

Pull irqchip fixes from Thomas Gleixner:
 "Another set of ARM SoC related irqchip fixes:
   - Plug a memory leak in gicv3-its
   - Limit features to the root gic interrupt controller
   - Add a missing barrier in the gic-v3 IAR access
   - Another compile test fix for sun4i"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3: Make sure read from ICC_IAR1_EL1 is visible on redestributor
  irqchip/gic: Only set the EOImodeNS bit for the root controller
  irqchip/gic: Only populate set_affinity for the root controller
  irqchip/gicv3-its: Fix memory leak in its_free_tables()
  irqchip/sun4i: Fix compilation outside of arch/arm

Pull x86 fixes from Thomas Gleixner:
 "Two small fixlets for x86:

   - Prevent a KASAN false positive in thread_saved_pc()

   - Fix a 32-bit truncation problem in the x86 numa code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/numa: Fix 32-bit memblock range truncation bug on 32-bit NUMA kernels
  x86: Fix KASAN false positives in thread_saved_pc()

Pull MIPS fixes from Ralf Baechle:
 "Here's the first round of MIPS fixes after the merge window:

   - Detect Octeon III's PCI correctly.
   - Fix return value of the MT7620 probing function.
   - Wire up the copy_file_range syscall.
   - Fix 64k page support on 32 bit kernels.
   - Fix the early Coherency Manager probe.
   - Allow only hardware-supported page sizes to be selected for R6000.
   - Fix corner cases for the RDHWR nstruction emulation on old hardware.
   - Fix FPU handling corner cases.
   - Remove stale entry for BCM33xx from the MAINTAINERS file.
   - 32 and 64 bit ELF headers are different, handle them correctly"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  mips: Differentiate between 32 and 64 bit ELF header
  MIPS: Octeon: Update OCTEON_FEATURE_PCIE for Octeon III
  MIPS: pci-mt7620: Fix return value check in mt7620_pci_probe()
  MIPS: Fix early CM probing
  MIPS: Wire up copy_file_range syscall.
  MIPS: Fix 64k page support for 32 bit kernels.
  MIPS: R6000: Don't allow 64k pages for R6000.
  MIPS: traps.c: Correct microMIPS RDHWR emulation
  MIPS: traps.c: Don't emulate RDHWR in the CpU #0 exception handler
  MAINTAINERS: Remove stale entry for BCM33xx chips
  MIPS: Fix FPU disable with preemption
  MIPS: Properly disable FPU in start_thread()
  MIPS: Fix buffer overflow in syscall_get_arguments()

Pull ARM fixes from Russell King:
 "A couple of ARM fixes from Linus for the ICST clock generator code"

[ "Linus" here is Linus Walleij.  Name-stealer.

       Linus "there can be only one" Torvalds ]

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8519/1: ICST: try other dividends than 1
  ARM: 8517/1: ICST: avoid arithmetic overflow in icst_hz()

Pull component helper fixes from Russell King:
 "A few fixes for problems people have encountered with the recent
  update to the component helpers"

* 'component' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  component: remove device from master match list on failed add
  component: Detach components when deleting master struct
  component: fix crash on x86_64 with hda audio drivers

Pull more rdma fixes from Doug Ledford:
 "I think we are getting pretty close to done now.  There are four
  one-off fixes in this update:

   - fix ipoib multicast joins
   - fix mlx4 error handling
   - fix mlx5 size computation
   - fix a thinko in core code"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma:
  IB/mlx5: Fix RC transport send queue overhead computation
  IB/ipoib: fix for rare multicast join race condition
  IB/core: Fix reading capability mask of the port info class
  net/mlx4: fix some error handling in mlx4_multi_func_init()

Pull SCSI target fixes from Nicholas Bellinger:
 "This includes the long awaited series to address a set of bugs around
  active I/O remote-port LUN_RESET, as well as properly handling this
  same case with concurrent fabric driver session disconnect ->
  reconnect.

  Note this set of LUN_RESET bug-fixes has been surviving extended
  testing on both v4.5-rc1 and v3.14.y code over the last weeks, and is
  CC'ed for stable as it's something folks using multiple ESX connected
  hosts with slow backends can certainly trigger.

  The highlights also include:

   - Fix WRITE_SAME/DISCARD emulation 4k sector conversion in
     target/iblock (Mike Christie)

   - Fix TMR abort interaction and AIO type TMR response in qla2xxx
     target (Quinn Tran + Swapnil Nagle)

   - Fix >= v3.17 stale descriptor pointer regression in qla2xxx target
     (Quinn Tran)

   - Fix >= v4.5-rc1 return regression with unmap_zeros_data_store new
     configfs store handler (nab)

   - Add CPU affinity flag + convert qla2xxx to use bit (Quinn + HCH +
     Bart)"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  qla2xxx: use TARGET_SCF_USE_CPUID flag to indiate CPU Affinity
  target/transport: add flag to indicate CPU Affinity is observed
  target: Fix incorrect unmap_zeroes_data_store return
  qla2xxx: Use ATIO type to send correct tmr response
  qla2xxx: Fix stale pointer access.
  target/user: Fix cast from pointer to phys_addr_t
  target: Drop legacy se_cmd->task_stop_comp + REQUEST_STOP usage
  target: Fix race with SCF_SEND_DELAYED_TAS handling
  target: Fix remote-port TMR ABORT + se_cmd fabric stop
  target: Fix TAS handling for multi-session se_node_acls
  target: Fix LUN_RESET active TMR descriptor handling
  target: Fix LUN_RESET active I/O handling for ACK_KREF
  qla2xxx: Fix TMR ABORT interaction issue between qla2xxx and TCM
  qla2xxx: Fix warning reported by static checker
  target: Fix WRITE_SAME/DISCARD conversion to linux 512b sectors

Pull thermal management fixes from Eduardo Valentin:
 "Specifics in this pull request:

   - Compilation fixes on SPEAR, and U8500 thermal drivers.
   - RCAR thermal driver now recognizes OF-thermal based thermal zones.
   - Small code rework on OF-thermal.
   - These change have been CI tested using KernelCI bot [1,2].  \o/

  I am taking over on Rui's behalf while he is out.  Happy New Chinese
  Year!

  [1] - https://kernelci.org/build/evalenti/kernel/v4.5-rc3-16-ga53b8394ec3c/
  [2] - https://kernelci.org/boot/all/job/evalenti/kernel/v4.5-rc3-16-ga53b8394ec3c/"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal:
  thermal: cpu_cooling: fix out of bounds access in time_in_idle
  thermal: allow u8500-thermal driver to be a module
  thermal: allow spear-thermal driver to be a module
  thermal: spear: use __maybe_unused for PM functions
  thermal: rcar: enable to use thermal-zone on DT
  thermal: of: use for_each_available_child_of_node for child iterator

Pull another sound fix from Takashi Iwai:
 "This contains a fix for the double-free of usb-audio MIDI device at
  probe failure"

* tag 'sound-fix-4.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: avoid freeing umidi object twice

Pull ARC fixes from Vineet Gupta:
 "I've been sitting on some of these fixes for a while.

   - Corner case of returning to delay slot from interrupt
   - Changing default interrupt prioiry level
   - Kconfig'ize support for super pages
   - Other minor fixes"

* tag 'arc-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: mm: Introduce explicit super page size support
  ARCv2: intc: Allow interruption by lowest priority interrupt
  ARCv2: Check for LL-SC livelock only if LLSC is enabled
  ARC: shrink cpuinfo by not saving full timer BCR
  ARCv2: clocksource: Rename GRTC -> GFRC ...
  ARCv2: STAR 9000950267: Handle return from intr to Delay Slot #2