The rdma_cm module will later use the P_Key from the BTH to de-mux
requests.

See discussion at:
  http://www.spinics.net/lists/netdev/msg336067.html

Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Liran Liss <liranl@mellanox.com>
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Add helper functions to access the IDRs by port-space and port number.

Pass around the port-space enum in cma.c instead of using pointers to
port-space IDRs.
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NYotam Kenneth <yotamke@mellanox.com>
Signed-off-by: NShachar Raindel <raindel@mellanox.com>
Signed-off-by: NGuy Shapiro <guysh@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

When receiving a connection request, rdma_cm needs to associate the request
with a network device, in order to disambiguate requests. To do this, it
needs to know the request's destination IP. For this the module needs to
allow getting this information from the private data in the request packet,
instead of relying on the information already being in the listening RDMA
CM ID.

When creating a new incoming connection ID, the code in
cma_save_ip{4,6}_info can no longer rely on the listener's private data to
find the port number, so it reads it from the requested service ID.
Signed-off-by: NGuy Shapiro <guysh@mellanox.com>
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NYotam Kenneth <yotamke@mellanox.com>
Signed-off-by: NShachar Raindel <raindel@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Enabling network namespaces for RDMA CM will allow processes on different
namespaces to listen on the same port. In order to leave namespace support
out of the CM layer, this requires that multiple RDMA CM IDs will be able
to share a single CM ID.

This patch adds infrastructure to retrieve an existing listening ib_cm_id,
based on its device and service ID, or create a new one if one does not
already exist. It also adds a reference count for such instances
(cm_id_private.listen_sharecount), and prevents cm_destroy_id from
destroying a CM if it is still shared. See the relevant discussion [1].

[1] Re: [PATCH v3 for-next 05/13] IB/cm: Reference count ib_cm_ids
    http://www.spinics.net/lists/netdev/msg328860.htmlReviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Expose the service ID on an incoming CM or SIDR request to the event
handler. This will allow the RDMA CM module to de-multiplex connection
requests based on the information encoded in the service ID.
Acked-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Implement the get_net_device_by_port_pkey_ip callback that returns network
device to ib_core according to connection parameters. Check the ipoib
device and iterate over all child devices to look for a match.

For each IPoIB device we iterate through all upper devices when searching
for a matching IP, in order to support bonding.
Signed-off-by: NGuy Shapiro <guysh@mellanox.com>
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NYotam Kenneth <yotamke@mellanox.com>
Signed-off-by: NShachar Raindel <raindel@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

In the case of IPoIB, and maybe in other cases, the network device is
managed by an upper-layer protocol (ULP). In order to expose this
network device to other users of the IB device, let ULPs implement
a callback that returns network device according to connection parameters.

The IB device and port, together with the P_Key and the GID should
be enough to uniquely identify the ULP net device. However, in current
kernels there can be multiple IPoIB interfaces created with the same GID.
Furthermore, such configuration may be desireable to support ipvlan-like
configurations for RDMA CM with IPoIB.  To resolve the device in these
cases the code will also take the IP address as an additional input.
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NYotam Kenneth <yotamke@mellanox.com>
Signed-off-by: NShachar Raindel <raindel@mellanox.com>
Signed-off-by: NGuy Shapiro <guysh@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

An ib_client callback that is called with the lists_rwsem locked only for
read is protected from changes to the IB client lists, but not from
ib_unregister_device() freeing its client data. This is because
ib_unregister_device() will remove the device from the device list with
lists_rwsem locked for write, but perform the rest of the cleanup,
including the call to remove() without that lock.

Mark client data that is undergoing de-registration with a new going_down
flag in the client data context. Lock the client data list with lists_rwsem
for write in addition to using the spinlock, so that functions calling the
callback would be able to lock only lists_rwsem for read and let callbacks
sleep.

Since ib_unregister_client() now marks the client data context, no need for
remove() to search the context again, so pass the client data directly to
remove() callbacks.
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Currently the RDMA subsystem's device list and client list are protected by
a single mutex. This prevents adding user-facing APIs that iterate these
lists, since using them may cause a deadlock. The patch attempts to solve
this problem by adding a read-write semaphore to protect the lists. Readers
now don't need the mutex, and are safe just by read-locking the semaphore.

The ib_register_device, ib_register_client, ib_unregister_device, and
ib_unregister_client functions are modified to lock the semaphore for write
during their respective list modification. Also, in order to make sure
client callbacks are called only between add() and remove() calls, the code
is changed to only add items to the lists after the add() calls and remove
from the lists before the remove() calls.

This patch attempts to solve a similar need [1] that was seen in the RoCE
v2 patch series.

[1] http://www.spinics.net/lists/linux-rdma/msg24733.htmlReviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Matan Barak <matanb@mellanox.com>
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This functionality already exists via the max_sge_rd
device capability.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Applications must not assume that max_sge and max_sge_rd are the same,
Hence expose max_sge_rd correctly as well.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Acked-by: NMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Applications must not assume that max_sge and max_sge_rd are the same,
Hence expose max_sge_rd correctly as well.
Reported-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Running checkpatch.pl on mad.c produces several
"ERROR: code indent should use tabs where possible" messages.
This patch fixes these.
Signed-off-by: NJeff Becker <Jeffrey.C.Becker@nasa.gov>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Signed-off-by: NAndrew Friedley <andrew.friedley@intel.com>
Signed-off-by: NArthur Kepner <arthur.kepner@intel.com>
Signed-off-by: NBrendan Cunningham <brendan.cunningham@intel.com>
Signed-off-by: NBrian Welty <brian.welty@intel.com>
Signed-off-by: NCaz Yokoyama <caz.yokoyama@intel.com>
Signed-off-by: NDean Luick <dean.luick@intel.com>
Signed-off-by: NDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: NEaswar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: NHarish Chegondi <harish.chegondi@intel.com>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NJim Snow <jim.m.snow@intel.com>
Signed-off-by: NJohn Gregor <john.a.gregor@intel.com>
Signed-off-by: NJubin John <jubin.john@intel.com>
Signed-off-by: NKaike Wan <kaike.wan@intel.com>
Signed-off-by: NKevin Pine <kevin.pine@intel.com>
Signed-off-by: NKyle Liddell <kyle.liddell@intel.com>
Signed-off-by: NMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: NMitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: NRavi Krishnaswamy <ravi.krishnaswamy@intel.com>
Signed-off-by: NSadanand Warrier <sadanand.warrier@intel.com>
Signed-off-by: NSanath Kumar <sanath.s.kumar@intel.com>
Signed-off-by: NSudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: NVlad Danushevsky <vladimir.danusevsky@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This patch adds the value of the CNP opcode to the existing list of enumerated
opcodes in ib_pack.h

Add common OPA header definitions for driver
build:
- opa_port_info.h
- opa_smi.h
- hfi1_user.h

Additionally, ib_mad.h, has additional definitions
that are common to ib_drivers including:
- trap support
- cca support

The qib driver has the duplication removed in favor
those in ib_mad.h
Reviewed-by: NMike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: NJohn, Jubin <jubin.john@intel.com>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The HW hasn't been sold since 2005, and the SW has definite bit rot.
Its time to remove it.  So move it to staging for a few releases and
then remove it after that.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

It is now time for the ipath driver to begin to be phased out of the kernel.
This patch moves the ipath driver from the Infiniband sub tree to the staging
area where it will remain until the code is removed from the kernel in a few
releases.
Reviewed-by: NMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: NDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Create the rdma directory in the staging area for use as we deprecate
some older drivers and as we bring in some new drivers that are in
need of work.  Update the MAINTAINERS file so that updates to these
files go to linux-rdma@vger.kernel.org.  Expected lifespan of this
directory is three releases for any deprecated drivers moved here
and an unknown, but theoretically bounded amount of time for the new
drivers as a new core RDMA transfer library needs to be written and
the drivers modified to use it in order for them to move out of this
directory.
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Add support for ipv6 address handling clip api provided by lld
Signed-off-by: NHariprasad Shenai <hariprasad@chelsio.com>
Acked-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Resolving a link-local IPv6 address with an unspecified source address
was broken by commit 5462eddd, which prevented the IPv6 stack from
learning the scope id of the link-local IPv6 address, causing random
failures as the IP stack chose a random link to resolve the address on.

This commit 5462eddd made us bail out of cma_check_linklocal early if
the address passed in was not an IPv6 link-local address. On the address
resolution path, the address passed in is the source address; if the
source address is the unspecified address, which is not link-local, we
will bail out early.

This is mostly correct, but if the destination address is a link-local
address, then we will be following a link-local route, and we'll need to
tell the IPv6 stack what the scope id of the destination address is.
This used to be done by last line of cma_check_linklocal, which is
skipped when bailing out early:

	dev_addr->bound_dev_if = sin6->sin6_scope_id;

(In cma_bind_addr, the sin6_scope_id of the source address is set to the
sin6_scope_id of the destination address, so this is correct)
This line is required in turn for the following line, L279 of
addr6_resolve, to actually inform the IPv6 stack of the scope id:

      fl6.flowi6_oif = addr->bound_dev_if;

Since we can only know we are in this failure case when we have access
to both the source IPv6 address and destination IPv6 address, we have to
deal with this further up the stack. So detect this failure case in
cma_bind_addr, and set bound_dev_if to the destination address scope id
to correct it.
Signed-off-by: NSpencer Baugh <sbaugh@catern.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Something like this:

CPU A                         CPU B
Acked-by: NSean Hefty <sean.hefty@intel.com>

========================      ================================
ucma_destroy_id()
 wait_for_completion()
                              .. anything
                                ucma_put_ctx()
                                  complete()
 .. continues ...
                              ucma_leave_multicast()
                               mutex_lock(mut)
                                 atomic_inc(ctx->ref)
                               mutex_unlock(mut)
 ucma_free_ctx()
  ucma_cleanup_multicast()
   mutex_lock(mut)
     kfree(mc)
                               rdma_leave_multicast(mc->ctx->cm_id,..

Fix it by latching the ref at 0. Once it goes to 0 mc and ctx cannot
leave the mutex(mut) protection.

The other atomic_inc in ucma_get_ctx is OK because mutex(mut) protects
it from racing with ucma_destroy_id.
Signed-off-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Acked-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

This enables ORD/IRD negotiation and its about time to enable it by
default
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Currently the sg tablesize, which dictates fast register page list
depth to use, does not take into account the limits of the rdma device.
So adjust it once we discover the device fastreg max depth limit.  Also
adjust the max_sectors based on the resulting sg tablesize.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The only place that assigns mr inside the loop already does a break.
So "if (mr)" will never be true here since the function initializes mr
to NULL at the top.  We can just drop the extra if and break here.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Acked-by: NEli Cohen  <eli@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The lkey table is allocated with with a get_user_pages() with an
order based on a number of index bits from a module parameter.

The underlying kernel code cannot allocate that many contiguous pages.

There is no reason the underlying memory needs to be physically
contiguous.

This patch:
- switches the allocation/deallocation to vmalloc/vfree
- caps the number of bits to 23 to insure at least 1 generation bit
  o this matches the module parameter description

Cc: stable@vger.kernel.org
Reviewed-by: NVinit Agnihotri <vinit.abhay.agnihotri@intel.com>
Signed-off-by: NMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Should be all the page sizes that are supported by the
device.
Reported-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

The mlx5 driver exposes device capability IB_DEVICE_LOCAL_DMA_LKEY
but does not set the the device local_dma_lkey. This breaks
rpcrdma drivers.

Query and set this lkey when creating the device resources.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Pull SCSI fixes from James Bottomley:
 "A couple of major (hang and deadlock) fixes with fortunately fairly
  rare triggering conditions.  The PM oops is only really triggered by
  people using enclosure services (rare) and the fnic driver is mostly
  used in enterprise environments"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  SCSI: Fix NULL pointer dereference in runtime PM
  fnic: Use the local variable instead of I/O flag to acquire io_req_lock in fnic_queuecommand() to avoid deadloack

Pull MIPS bug fixes from Ralf Baechle:
 "Two more fixes for 4.2.

  One fixes a build issue with the LLVM assembler - LLVM assembler macro
  names are case sensitive, GNU as macro names are insensitive; the
  other corrects a license string (GPL v2, not GPLv2) such that the
  module loader will recognice the license correctly"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  FIRMWARE: bcm47xx_nvram: Fix module license.
  MIPS: Fix LLVM build issue.

Pull 9p regression fix from Al Viro:
 "Fix for breakage introduced when switching p9_client_{read,write}() to
  struct iov_iter * (went into 4.1)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  9p: ensure err is initialized to 0 in p9_client_read/write

Some use of those functions were providing unitialized values to those
functions. Notably, when reading 0 bytes from an empty file on a 9P
filesystem, the return code of read() was not 0.

Tested with this simple program:

    #include <assert.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <unistd.h>

    int main(int argc, const char **argv)
    {
        assert(argc == 2);
        char buffer[256];
        int fd = open(argv[1], O_RDONLY|O_NOCTTY);
        assert(fd >= 0);
        assert(read(fd, buffer, 0) == 0);
        return 0;
    }

Cc: stable@vger.kernel.org # v4.1
Signed-off-by: NVincent Bernat <vincent@bernat.im>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Pull ARM fixes from Russell King:
 "Another couple of small ARM fixes.

  A patch from Masahiro Yamada who noticed that "make -jN all zImage"
  would end up generating bad images where N > 1, and a patch from
  Nicolas to fix the Marvell CPU user access optimisation code when page
  faults are disabled"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8418/1: add boot image dependencies to not generate invalid images
  ARM: 8414/1: __copy_to_user_memcpy: fix mmap semaphore usage

Pull x86 fixes from Ingo Molnar:
 "Various low level fixes: fix more fallout from the FPU rework and the
  asm entry code rework, plus an MSI rework fix, and an idle-tracing fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu/math-emu: Fix crash in fork()
  x86/fpu/math-emu: Fix math-emu boot crash
  x86/idle: Restore trace_cpu_idle to mwait_idle() calls
  x86/irq: Build correct vector mapping for multiple MSI interrupts
  Revert "sched/x86_64: Don't save flags on context switch"

Pull perf fixes from Ingo Molnar:
 "Tooling fixes: a 'perf record' deadlock fix plus debuggability fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf top: Show backtrace when handling a SIGSEGV on --stdio mode
  perf tools: Fix buildid processing
  perf tools: Make fork event processing more resilient
  perf tools: Avoid deadlock when map_groups are broken

Pull irq fixes from Thomas Gleixner:
 "A series of small fixlets for a regression visible on OMAP devices
  caused by the conversion of the OMAP interrupt chips to hierarchical
  interrupt domains.  Mostly one liners on the driver side plus a small
  helper function in the core to avoid open coded mess in the drivers"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/crossbar: Restore set_wake functionality
  irqchip/crossbar: Restore the mask on suspend behaviour
  ARM: OMAP: wakeupgen: Restore the irq_set_type() mechanism
  irqchip/crossbar: Restore the irq_set_type() mechanism
  genirq: Introduce irq_chip_set_type_parent() helper
  genirq: Don't return ENOSYS in irq_chip_retrigger_hierarchy

Pull timer fixes from Thomas Gleixner:
 "Two minimalistic fixes for 4.2 regressions:

   - Eric fixed a thinko in the timer_list base switching code caused by
     the overhaul of the timer wheel.  It can cause a cpu to see the
     wrong base for a timer while we move the timer around.

   - Guenter fixed a regression for IMX if booted w/o device tree, where
     the timer interrupt is not initialized and therefor the machine
     fails to boot"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/imx: Fix boot with non-DT systems
  timer: Write timer->flags atomically

During later stages of math-emu bootup the following crash triggers:

	 math_emulate: 0060:c100d0a8
	 Kernel panic - not syncing: Math emulation needed in kernel
	 CPU: 0 PID: 1511 Comm: login Not tainted 4.2.0-rc7+ #1012
	 [...]
	 Call Trace:
	  [<c181d50d>] dump_stack+0x41/0x52
	  [<c181c918>] panic+0x77/0x189
	  [<c1003530>] ? math_error+0x140/0x140
	  [<c164c2d7>] math_emulate+0xba7/0xbd0
	  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
	  [<c1109c3c>] ? __alloc_pages_nodemask+0x12c/0x870
	  [<c136ac20>] ? proc_clear_tty+0x40/0x70
	  [<c136ac6e>] ? session_clear_tty+0x1e/0x30
	  [<c1003530>] ? math_error+0x140/0x140
	  [<c1003575>] do_device_not_available+0x45/0x70
	  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
	  [<c18258e6>] error_code+0x5a/0x60
	  [<c1003530>] ? math_error+0x140/0x140
	  [<c100d0a8>] ? fpu__copy+0x138/0x1c0
	  [<c100c205>] arch_dup_task_struct+0x25/0x30
	  [<c1048cea>] copy_process.part.51+0xea/0x1480
	  [<c115a8e5>] ? dput+0x175/0x200
	  [<c136af70>] ? no_tty+0x30/0x30
	  [<c1157242>] ? do_vfs_ioctl+0x322/0x540
	  [<c104a21a>] _do_fork+0xca/0x340
	  [<c1057b06>] ? SyS_rt_sigaction+0x66/0x90
	  [<c104a557>] SyS_clone+0x27/0x30
	  [<c1824a80>] sysenter_do_call+0x12/0x12

The reason is the incorrect assumption in fpu_copy(), that FNSAVE
can be executed from math-emu kernels as well.

Don't try to copy the registers, the soft state will be copied
by fork anyway, so the child task inherits the parent task's
soft math state.

With this fix applied math-emu kernels boot up fine on modern
hardware and the 'no387 nofxsr' boot options.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

On a math-emu bootup the following crash occurs:

	Initializing CPU#0
	------------[ cut here ]------------
	kernel BUG at arch/x86/kernel/traps.c:779!
	invalid opcode: 0000 [#1] SMP
	[...]
	EIP is at do_device_not_available+0xe/0x70
	[...]
	Call Trace:
	 [<c18238e6>] error_code+0x5a/0x60
	 [<c1002bd0>] ? math_error+0x140/0x140
	 [<c100bbd9>] ? fpu__init_cpu+0x59/0xa0
	 [<c1012322>] cpu_init+0x202/0x330
	 [<c104509f>] ? __native_set_fixmap+0x1f/0x30
	 [<c1b56ab0>] trap_init+0x305/0x346
	 [<c1b548af>] start_kernel+0x1a5/0x35d
	 [<c1b542b4>] i386_start_kernel+0x82/0x86

The reason is that in the following commit:

  b1276c48 ("x86/fpu: Initialize fpregs in fpu__init_cpu_generic()")

I failed to consider math-emu's limitation that it cannot execute the
FNINIT instruction in kernel mode.

The long term fix might be to allow math-emu to execute (certain) kernel
mode FPU instructions, but for now apply the safe (albeit somewhat ugly)
fix: initialize the emulation state explicitly without trapping out to
the FPU emulator.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>