This reverts commit 353d6d6c, which is
no longer needed, now that the irq-armada-370-xp driver properly
re-enables per-CPU interrupt on both the boot CPU and secondary CPUs
after resume.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Commit d17cab44 ("irqchip: Kill off set_irq_flags usage") changed
the code of armada_370_xp_mpic_irq_map() from using set_irq_flags() to
irq_set_probe().

While the commit log seems to imply that there are no functional
changes, there are indeed functional changes introduced by this commit:
the IRQ_NOAUTOEN flag is no longer cleared. This functional change
caused a regression on Armada XP, which no longer works properly after
suspend/resume because per-CPU interrupts remain disabled. This
regression was temporarly worked around in commit
353d6d6c ("irqchip/armada-370-xp: Fix regression by clearing
IRQ_NOAUTOEN"), but it is not the most satisfying solution. This commit
implements the solution that was initially discussed with Thomas
Gleixner.

Due to how the hardware registers work, the irq-armada-370-xp cannot
simply save/restore a bunch of registers at suspend/resume to make sure
that the interrupts remain in the same state after resuming. Therefore,
it relies on the kernel to say whether the interrupt is disabled or not,
using the irqd_irq_disabled() function. This was all working fine while
the IRQ_NOAUTOEN flag was cleared.

With the change introduced by Rob Herring in d17cab44, the
IRQ_NOAUTOEN flag is now set for all interrupts. irqd_irq_disabled()
returns false for per-CPU interrupts, and therefore our per-CPU
interrupts are no longer re-enabled after resume.

This commit fixes that by using irqd_irq_disabled() only for global
interrupts, and using the newly introduced irq_percpu_is_enabled() for
per-CPU interrupts.

Also, it fixes a related problems that per-CPU interrupts were only
re-enabled on the boot CPU and not other CPUs. Until now this wasn't a
problem since on this platform, only the local timers are using per-CPU
interrupts and the local timers of secondary CPUs are turned off/on
during CPU hotplug before suspend, after after resume. However, since
Linux 4.4, we are also be using per-CPU interrupts for the network
controller, so we need to properly restore the per-CPU interrupts on
secondary CPUs as well.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Since the overall logic of the driver to handle the global and per-CPU
masking of the interrupts is far from trivial, this commit adds a long
comment detailing how the hardware operates and what strategy the
driver implements on top of that.
Acked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

In order to clarify to which register base the various register
definitions apply, this commit re-orders them, and adds a comment that
clearly indicate which registers are relative to "main_int_base" and
which registers are relative to "per_cpu_int_base".
Acked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Just skip the irq affinity setting when the target cpu is the same as
current setting.
This is a small optimization for irq affinity setting logic.
Signed-off-by: NMaJun <majun258@huawei.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The call to pci_for_each_dma_alias() in the ITS PCI code has aroused
suspicion in the past, and upon closer inspection does turn out to be
completely backwards. Rather than iterating through each RID alias of
the given device, what we actually want to be doing here is iterating
through all the *other* devices which may also alias the same RID, in
order to size the table for the worst case.

Do the right thing by ignoring the initial DMA aliases themselves and
just using that walk to detect an aliasing bridge, then walking back
down the bus topology as necessary to actually count everything else.

Our alias handling still isn't perfect, since we don't account for the
cases of certain bridges only taking ownership of transactions under
particular circumstances, but without completely reworking the ITS code
to cope with the notion of multiple DevIDs per device, it'll have to do.
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

struct irq_domain_ops is not modified, so it can be made const.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

struct irq_domain_ops is not modified, so it can be made const.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

struct irq_domain_ops is not modified, so it can be made const.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

struct irq_domain_ops is not modified, so it can be made const.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

struct irq_domain_ops is not modified, so it can be made const.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

struct irq_domain_ops is not modified, so it can be made const.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The R_INTC on the A31 is undocumented. It was previously supported
by the sun6i-a31-sc-nmi compatible. This compatible however required
the register region to start at the first used register, rather than
the boundaries laid out in the SoC's memory map. The new compatible
fixes the alignment, while also naming it properly.

Since the only difference between the old and new compatibles are
a fixed offset for the registers, and since the old one is deprecated,
this patch adds a set of register defines for the new compatible,
while modifying the old set to reference the new set minus a fixed
offset.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The A31 and later have an R_INTC block which handles the NMI interrupt
pin on the SoC. This interrupt pin is used by the external PMIC to
signal interrupts to the SoC.

While this hardware block is undocumented, the interrupt offsets
combined with the register regions for the existing "sun6i-a31-sc-nmi"
compatible line up with the old interrupt controller found on the A10.
Experiments show that only the first 32 interrupt lines can be enabled,
and only the first (NMI) interrupt is actually connected.

This patch adds a new, properly named compatible for the A31 R_INTC
block, which requires the register region to be properly aligned to
the block boundary. For comparison, the old "sun6i-a31-sc-nmi"
compatible had its register region aligned with the first used
register. This didn't match up with the memory map in the SoC's
datasheet/user manual.

Since the new compatible supercedes the old one, deprecate the old one.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The sunxi_sc_nmi_reg_offs, which hold the register offsets for the
various variants, is never modified, and only used at init time within
the init functions referenced by IRQCHIP_DECLARE, which themselves are
tagged __init.

Const-ify the sunxi_sc_nmi_reg_offs structures, and tag them as
__initconst.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

This is a pure code move to reorder the various sunxi_sc_nmi_reg_offs'
by family and alphabetical order. No functionality changes.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The sunxi-nmi disables all its interrupts and clears any pending
interrupts at probe time.

Add comments documenting it, just to make it clear.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The sunxi-nmi driver has a bunch of raw register offsets and bit values.

Convert them into define macros for better readability.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

This fixes a problem with reading files larger than 2GB from a UFS-2
file system:

    https://bugzilla.kernel.org/show_bug.cgi?id=195721

The incorrect UFS s_maxsize limit became a problem as of commit
c2a9737f ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
which started using s_maxbytes to avoid a page index overflow in
do_generic_file_read().

That caused files to be truncated on UFS-2 file systems because the
default maximum file size is 2GB (MAX_NON_LFS) and UFS didn't update it.

Here I simply increase the default to a common value used by other file
systems.
Signed-off-by: NRichard Narron <comet.berkeley@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Will B <will.brokenbourgh2877@gmail.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: <stable@vger.kernel.org> # v4.9 and backports of c2a9737fSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull NFS client bugfixes from Trond Myklebust:
 "Bugfixes include:

   - Fix a typo in commit e0926934 ("NFS append COMMIT after
     synchronous COPY") that breaks copy offload

   - Fix the connect error propagation in xs_tcp_setup_socket()

   - Fix a lock leak in nfs40_walk_client_list

   - Verify that pNFS requests lie within the offset range of the layout
     segment"

* tag 'nfs-for-4.12-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  nfs: Mark unnecessarily extern functions as static
  SUNRPC: ensure correct error is reported by xs_tcp_setup_socket()
  NFSv4.0: Fix a lock leak in nfs40_walk_client_list
  pnfs: Fix the check for requests in range of layout segment
  xprtrdma: Delete an error message for a failed memory allocation in xprt_rdma_bc_setup()
  pNFS/flexfiles: missing error code in ff_layout_alloc_lseg()
  NFS fix COMMIT after COPY

Pull tty fix from Greg KH:
 "Here is a single tty core fix for 4.12-rc4. It reverts a patch that a
  lot of people reported as causing lockdep and other warnings.

  Right after I reverted this in my tree, it seems like another
  "correct" fix might have shown up, but it's too late in the release
  cycle to be messing with tty core locking, so let's just revert this
  for now to go back how things always have been and try it again for
  4.13.

  This has not been in linux-next as I only reverted it a few hours ago"

* tag 'tty-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  Revert "tty: fix port buffer locking"

Pull input subsystem fixes from Dmitry Torokhov:

 - a couple of regression fixes in synaptics and axp20x-pek drivers

 - try to ease transition from PS/2 to RMI for Synaptics touchpad users
   by ensuring we do not try to activate RMI mode when RMI SMBus support
   is not enabled, and nag users a bit to enable it

 - plus a couple of other changes that seemed worthwhile for this
   release

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: axp20x-pek - switch to acpi_dev_present and check for ACPI0011 too
  Input: axp20x-pek - only check for "INTCFD9" ACPI device on Cherry Trail
  Input: tm2-touchkey - use LEN_ON as boolean value instead of LED_FULL
  Input: synaptics - tell users to report when they should be using rmi-smbus
  Input: synaptics - warn the users when there is a better mode
  Input: synaptics - keep PS/2 around when RMI4_SMB is not enabled
  Input: synaptics - clear device info before filling in
  Input: silead - disable interrupt during suspend

Pull RTC fixlet from Alexandre Belloni:
 "A single patch, not really a fix but I don't think there is any reason
  to delay it.

  Change the mailing list address"

* tag 'rtc-4.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
  MAINTAINERS: update RTC mailing list

Pull SCSI fixes from James Bottomley:
 "This is nine fixes, seven of which are for the qedi driver (new as of
  4.10) the other two are a use after free in the cxgbi drivers and a
  potential NULL dereference in the rdac device handler"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: libcxgbi: fix skb use after free
  scsi: qedi: Fix endpoint NULL panic during recovery.
  scsi: qedi: set max_fin_rt default value
  scsi: qedi: Set firmware tcp msl timer value.
  scsi: qedi: Fix endpoint NULL panic in qedi_set_path.
  scsi: qedi: Set dma_boundary to 0xfff.
  scsi: qedi: Correctly set firmware max supported BDs.
  scsi: qedi: Fix bad pte call trace when iscsiuio is stopped.
  scsi: scsi_dh_rdac: Use ctlr directly in rdac_failover_get()

Pull rdma fixes from Doug Ledford:
 "For the most part this is just a minor -rc cycle for the rdma
  subsystem. Even given that this is all of the -rc patches since the
  merge window closed, it's still only about 25 patches:

   - Multiple i40iw, nes, iw_cxgb4, hfi1, qib, mlx4, mlx5 fixes

   - A few upper layer protocol fixes (IPoIB, iSER, SRP)

   - A modest number of core fixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (26 commits)
  RDMA/SA: Fix kernel panic in CMA request handler flow
  RDMA/umem: Fix missing mmap_sem in get umem ODP call
  RDMA/core: not to set page dirty bit if it's already set.
  RDMA/uverbs: Declare local function static and add brackets to sizeof
  RDMA/netlink: Reduce exposure of RDMA netlink functions
  RDMA/srp: Fix NULL deref at srp_destroy_qp()
  RDMA/IPoIB: Limit the ipoib_dev_uninit_default scope
  RDMA/IPoIB: Replace netdev_priv with ipoib_priv for ipoib_get_link_ksettings
  RDMA/qedr: add null check before pointer dereference
  RDMA/mlx5: set UMR wqe fence according to HCA cap
  net/mlx5: Define interface bits for fencing UMR wqe
  RDMA/mlx4: Fix MAD tunneling when SRIOV is enabled
  RDMA/qib,hfi1: Fix MR reference count leak on write with immediate
  RDMA/hfi1: Defer setting VL15 credits to link-up interrupt
  RDMA/hfi1: change PCI bar addr assignments to Linux API functions
  RDMA/hfi1: fix array termination by appending NULL to attr array
  RDMA/iw_cxgb4: fix the calculation of ipv6 header size
  RDMA/iw_cxgb4: calculate t4_eq_status_entries properly
  RDMA/iw_cxgb4: Avoid touch after free error in ARP failure handlers
  RDMA/nes: ACK MPA Reply frame
  ...

This reverts commit 925bb1ce.

It causes lots of warnings and problems so for now, let's just revert
it.

Reported-by: <valdis.kletnieks@vt.edu>
Reported-by: NRussell King <linux@armlinux.org.uk>
Reported-by: NSergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Reported-by: NJiri Slaby <jslaby@suse.cz>
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Acked-by: NVegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

nfs_initialise_sb() and nfs_clone_super() are declared as extern even
though they are used only in fs/nfs/super.c. Mark them as static.

Also remove explicit 'inline' directive from nfs_initialise_sb() and
leave it upto compiler to decide whether inlining is worth it.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Merge tag 'hwmon-for-linus-v4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:
 "A couple of patches for the aspeed pwm fan driver"

* tag 'hwmon-for-linus-v4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (aspeed-pwm-tacho) make fan/pwm names start with index 1
  hwmon: (aspeed-pwm-tacho) Call of_node_put() on a node not claimed
  hwmon: (aspeed-pwm-tacho) On read failure return -ETIMEDOUT
  hwmon: (aspeed-pwm-tacho) Select REGMAP

Pull MTD fixes from Brian Norris:
 "NAND updates from Boris:

  tango fixes:
   - Add missing MODULE_DEVICE_TABLE() in tango_nand.c
   - Update the number of corrected bitflips

  core fixes:
   - Fix a long standing memory leak in nand_scan_tail()
   - Fix several bugs introduced by the per-vendor init/detection
     infrastructure (introduced in 4.12)
   - Add a static specifier to nand_ooblayout_lp_hamming_ops definition"

* tag 'for-linus-20170602' of git://git.infradead.org/linux-mtd:
  mtd: nand: make nand_ooblayout_lp_hamming_ops static
  mtd: nand: tango: Update ecc_stats.corrected
  mtd: nand: tango: Export OF device ID table as module aliases
  mtd: nand: samsung: warn about un-parseable ECC info
  mtd: nand: free vendor-specific resources in init failure paths
  mtd: nand: drop unneeded module.h include
  mtd: nand: don't leak buffers when ->scan_bbt() fails

Make fan and pwm names in sysfs start with index 1 in accordance to
Documentation/hwmon/sysfs-interface conventions.

Current implementation starts with index 0, making tools such as
sensors(1) skip the first fan.
Signed-off-by: NStefan Schaeckeler <sschaeck@cisco.com>
Fixes: 2d7a548a ("drivers: hwmon: Support for ASPEED PWM/Fan tach")
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Call of_node_put() on a node claimed with of_node_get() or by any other
means such as for_each_child_of_node().
Signed-off-by: NStefan Schaeckeler <sschaeck@cisco.com>
Fixes: 2d7a548a ("drivers: hwmon: Support for ASPEED PWM/Fan tach")
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

acpi_dev_found checks that there is a matching ACPI node, but it
may be disabled (_STA method returns 0) in which case the
soc_button_array driver will not bind to it and axp20x-pek should
handle the power-button.

This commit switches from acpi_dev_found to acpi_dev_present to
avoid not registering an input-dev for the powerbutton when there
is a disabled PNP0C40 device.

The ACPI-6.0 standard defines a standard gpio button device using
the ACPI0011 HID replacing the custom PNP0C40 gpio device, many
newer devices define both PNP0C40 and ACPI0011 devices enabling one
or the other depending on whether the BIOS thinks it is going to boot
Android or Windows.

This commit adds a check for the ACPI0011 device, so that if
either device is present *and* enabled we don't register an input-dev
for the powerbutton.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

Commit 9b13a4ca ("Input: axp20x-pek - do not register input device
on some systems") added a check for the INTCFD9 ACPI device which also
handles the powerbutton as on some systems the powerbutton is connected
to both the PMIC, handled by axp20x-pek, and to a gpio on the SoC, handled
by soc_button_array which attaches itself to the INTCFD9 ACPI device.

Testing + comparing DSDTs has shown that this only happens on Cherry
Trail devices with an AXP288 PMIC, the AXP288 PMIC is also used on
Bay Trail devices but there the power button is only connected to
the PMIC and not handled by soc_button_array.

This means that the INTCFD9 check has caused a regression on Bay Trail
devices, causing power-button presses to no longer be seen.

This commit fixes this by limiting the check to devices where the ACPI
node for the AXP288 contains a _HRV (hardware revision) attribute with
a value of 3 which indicates we are dealing with a Cherry Trail platform.

Fixes: 9b13a4ca ("Input: axp20x-pek - do not register input ...")
Reported-by: NСергей Трусов <t.rus76@ya.ru>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

Merge with mainline to get acpi_dev_present() needed by patches to
axp20x-pek driver.

Pull ACPI fixes from Rafael Wysocki:
 "These revert one more problematic commit related to the ACPI-based
  handling of laptop lids and make some unuseful error messages coming
  from ACPICA go away.

  Specifics:

   - Revert one more commit related to the ACPI-based handling of laptop
     lids that changed the default behavior on laptops that booted with
     closed lids and introduced a regression there (Benjamin Tissoires).

   - Add a missing acpi_put_table() to the code implementing the
     /sys/firmware/acpi/tables interface to prevent a counter in the
     ACPICA core from overflowing (Dan Williams).

   - Drop error messages printed by ACPICA on acpi_get_table() reference
     counting mismatches as they need not indicate real errors at this
     point (Lv Zheng)"

* tag 'acpi-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPICA: Tables: Fix regression introduced by a too early mechanism enabling
  Revert "ACPI / button: Change default behavior to lid_init_state=open"
  ACPI / sysfs: fix acpi_get_table() leak / acpi-sysfs denial of service

Pull power management fixes from Rafael Wysocki:
 "These fix two bugs in error code paths in the cpufreq core and in the
  kirkwood-cpufreq driver.

  Specifics:

   - Make cpufreq_register_driver() return an error if the ->init()
     calls fail for all CPUs to prevent non-functional drivers from
     hanging around for no reason (David Arcari).

   - Make kirkwood-cpufreq check the return value of
     clk_prepare_enable() (which may fail) as appropriate (Arvind
     Yadav)"

* tag 'pm-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: kirkwood-cpufreq:- Handle return value of clk_prepare_enable()
  cpufreq: cpufreq_register_driver() should return -ENODEV if init fails

Pull /dev/random bug fix from Ted Ts'o:
 "Fix a race on architectures with prioritized interrupts (such as m68k)
  which can causes crashes in drivers/char/random.c:get_reg()"

* tag 'random_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
  fix race in drivers/char/random.c:get_reg()

Merge misc fixes from Andrew Morton:
 "15 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  scripts/gdb: make lx-dmesg command work (reliably)
  mm: consider memblock reservations for deferred memory initialization sizing
  mm/hugetlb: report -EHWPOISON not -EFAULT when FOLL_HWPOISON is specified
  mlock: fix mlock count can not decrease in race condition
  mm/migrate: fix refcount handling when !hugepage_migration_supported()
  dax: fix race between colliding PMD & PTE entries
  mm: avoid spurious 'bad pmd' warning messages
  mm/page_alloc.c: make sure OOM victim can try allocations with no watermarks once
  pcmcia: remove left-over %Z format
  slub/memcg: cure the brainless abuse of sysfs attributes
  initramfs: fix disabling of initramfs (and its compression)
  mm: clarify why we want kmalloc before falling backto vmallock
  frv: declare jiffies to be located in the .data section
  include/linux/gfp.h: fix ___GFP_NOLOCKDEP value
  ksm: prevent crash after write_protect_page fails

lx-dmesg needs access to the log_buf symbol from printk.c.
Unfortunately, the symbol log_buf also exists in BPF's verifier.c and
hence gdb can pick one or the other.  If it happens to pick BPF's
log_buf, lx-dmesg doesn't work:

  (gdb) lx-dmesg
  Python Exception <class 'gdb.MemoryError'> Cannot access memory at address 0x0:
  Error occurred in Python command: Cannot access memory at address 0x0
  (gdb) p log_buf
  $15 = 0x0

Luckily, GDB has a way to deal with this, see
  https://sourceware.org/gdb/onlinedocs/gdb/Symbols.html

  (gdb) info variables ^log_buf$
  All variables matching regular expression "^log_buf$":

  File <linux.git>/kernel/bpf/verifier.c:
  static char *log_buf;

  File <linux.git>/kernel/printk/printk.c:
  static char *log_buf;
  (gdb) p 'verifier.c'::log_buf
  $1 = 0x0
  (gdb) p 'printk.c'::log_buf
  $2 = 0x811a6aa0 <__log_buf> ""
  (gdb) p &log_buf
  $3 = (char **) 0x8120fe40 <log_buf>
  (gdb) p &'verifier.c'::log_buf
  $4 = (char **) 0x8120fe40 <log_buf>
  (gdb) p &'printk.c'::log_buf
  $5 = (char **) 0x8048b7d0 <log_buf>

By being explicit about the location of the symbol, we can make lx-dmesg
work again.  While at it, do the same for the other symbols we need from
printk.c

Link: http://lkml.kernel.org/r/20170526112222.3414-1-git@andred.netSigned-off-by: NAndré Draszik <git@andred.net>
Tested-by: NKieran Bingham <kieran@bingham.xyz>
Acked-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>