Implement pci_acpi_scan_root() and other arch-specific calls so ARM64 can
use ACPI to setup and enumerate PCI buses.

Use memory-mapped configuration space information from either the ACPI
_CBA method or the MCFG table and the ECAM library and generic ECAM config
accessor ops.

Implement acpi_pci_bus_find_domain_nr() to retrieve the domain number from
the acpi_pci_root structure.

Implement pcibios_add_bus() and pcibios_remove_bus() to call
acpi_pci_add_bus() and acpi_pci_remove_bus() for ACPI slot management and
other configuration.
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

On ACPI systems, the PCI_Config OperationRegion allows AML to access PCI
configuration space.  The ACPI CA AML interpreter uses performs config
space accesses with acpi_os_read_pci_configuration() and
acpi_os_write_pci_configuration(), which are OS-dependent functions
supplied by acpi/osl.c.

Implement the arch-specific raw_pci_read() and raw_pci_write() interfaces
used by acpi/osl.c for PCI_Config accesses.

N.B. PCI_Config accesses are not supported before PCI bus enumeration.

[bhelgaas: changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

To enable PCI legacy IRQs on platforms booting with ACPI, arch code should
include ACPI-specific callbacks that parse and set-up the device IRQ
number, equivalent to the DT boot path. Owing to the current ACPI core scan
handlers implementation, ACPI PCI legacy IRQs bindings cannot be parsed at
device add time, since that would trigger ACPI scan handlers ordering
issues depending on how the ACPI tables are defined.

To solve this problem and consolidate FW PCI legacy IRQs parsing in one
single pcibios callback (pending final removal), this patch moves DT PCI
IRQ parsing to the pcibios_alloc_irq() callback (called by PCI core code at
driver probe time) and adds ACPI PCI legacy IRQs parsing to the same
callback too, so that FW PCI legacy IRQs parsing is confined in one single
arch callback that can be easily removed when code parsing PCI legacy IRQs
is consolidated and moved to core PCI code.
Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Extend pci_bus_find_domain_nr() so it can find the domain from either:

  - ACPI, via the new acpi_pci_bus_find_domain_nr() interface, or
  - DT, via of_pci_bus_find_domain_nr()

Note that this is only used for CONFIG_PCI_DOMAINS_GENERIC=y, so it does
not affect x86 or ia64.

[bhelgaas: changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

pci_bus_find_domain_nr() retrieves the host bridge domain number in a
DT-specific way.  Rename it to of_pci_bus_find_domain_nr() to reflect that,
so we can add a corresponding function for ACPI.

[bhelgaas: changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Instead of assigning bus->domain_nr inside pci_bus_assign_domain_nr(),
return the domain and let the caller do the assignment.  Rename
pci_bus_assign_domain_nr() to pci_bus_find_domain_nr() to reflect this.

No functional change intended.

[bhelgaas: changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

On ACPI systems that support memory-mapped config space access, i.e., ECAM,
the PCI Firmware Specification says the OS can learn where the ECAM space
is from either:

  - the static MCFG table (for non-hotpluggable bridges), or
  - the _CBA method (for hotpluggable bridges)

The current MCFG table handling code cannot be easily generalized owing to
x86-specific quirks, which makes it hard to reuse on other architectures.

Implement generic MCFG handling from scratch, including:

  - Simple MCFG table parsing (via pci_mmcfg_late_init() as in current x86)
  - MCFG region lookup for a (domain, bus_start, bus_end) tuple

[bhelgaas: changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

On platforms with memory-mapped I/O ports, such as ia64 and ARM64, we have
to map the memory region and coordinate it with the arch's I/O port
accessors.

For ia64, we do this in arch code because it supports both dense (1 byte
per I/O port) and sparse (1024 bytes per I/O port) memory mapping.  For
arm64, we only support dense mappings, which we can do in the generic code
with pci_register_io_range() and pci_remap_iospace().

Add acpi_pci_root_remap_iospace() to remap dense memory-mapped I/O port
space when adding a bridge, and call pci_unmap_iospace() to release the
space when removing the bridge.

[bhelgaas: changelog, move #ifdef inside acpi_pci_root_remap_iospace()]
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
[Tomasz: merged in Sinan's patch to unmap IO resources properly, updated changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Add pci_unmap_iospace() to undo what pci_remap_iospace() did.

This is needed to support hotplug removal of host bridges that use
pci_remap_iospace().

[bhelgaas: changelog]
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Add a parent device field to struct pci_config_window.  The parent is not
saved now, but will be useful to save it in some cases.  For ACPI on ARM64,
it can be used to setup ACPI companion and domain.

Since the parent dev is in struct pci_config_window now, we need not pass
it to the init function as a separate argument.
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

This header will be used from arch/arm64 for ACPI PCI implementation so it
needs to be moved out of drivers/pci.

Update users of the header file to use the new name.  No functional
changes.
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Pull parisc fixes from Helge Deller:

 - Fix printk time stamps on SMP systems which got wrong due to a patch
   which was added during the merge window

 - Fix two bugs in the stack backtrace code: Races in module unloading
   and possible invalid accesses to memory due to wrong instruction
   decoding (Mikulas Patocka)

 - Fix userspace crash when syscalls access invalid unaligned userspace
   addresses.  Those syscalls will now return EFAULT as expected.
   (tagged for stable kernel series)

* 'parisc-4.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Move die_if_kernel() prototype into traps.h header
  parisc: Fix pagefault crash in unaligned __get_user() call
  parisc: Fix printk time during boot
  parisc: Fix backtrace on PA-RISC

Pull key handling update from James Morris:
 "This alters a new keyctl function added in the current merge window to
  allow for a future extension planned for the next merge window"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  KEYS: Add placeholder for KDF usage with DH

The /dev/ptmx device node is changed to lookup the directory entry "pts"
in the same directory as the /dev/ptmx device node was opened in.  If
there is a "pts" entry and that entry is a devpts filesystem /dev/ptmx
uses that filesystem.  Otherwise the open of /dev/ptmx fails.

The DEVPTS_MULTIPLE_INSTANCES configuration option is removed, so that
userspace can now safely depend on each mount of devpts creating a new
instance of the filesystem.

Each mount of devpts is now a separate and equal filesystem.

Reserved ttys are now available to all instances of devpts where the
mounter is in the initial mount namespace.

A new vfs helper path_pts is introduced that finds a directory entry
named "pts" in the directory of the passed in path, and changes the
passed in path to point to it.  The helper path_pts uses a function
path_parent_directory that was factored out of follow_dotdot.

In the implementation of devpts:
 - devpts_mnt is killed as it is no longer meaningful if all mounts of
   devpts are equal.
 - pts_sb_from_inode is replaced by just inode->i_sb as all cached
   inodes in the tty layer are now from the devpts filesystem.
 - devpts_add_ref is rolled into the new function devpts_ptmx.  And the
   unnecessary inode hold is removed.
 - devpts_del_ref is renamed devpts_release and reduced to just a
   deacrivate_super.
 - The newinstance mount option continues to be accepted but is now
   ignored.

In devpts_fs.h definitions for when !CONFIG_UNIX98_PTYS are removed as
they are never used.

Documentation/filesystems/devices.txt is updated to describe the current
situation.

This has been verified to work properly on openwrt-15.05, centos5,
centos6, centos7, debian-6.0.2, debian-7.9, debian-8.2, ubuntu-14.04.3,
ubuntu-15.10, fedora23, magia-5, mint-17.3, opensuse-42.1,
slackware-14.1, gentoo-20151225 (13.0?), archlinux-2015-12-01.  With the
caveat that on centos6 and on slackware-14.1 that there wind up being
two instances of the devpts filesystem mounted on /dev/pts, the lower
copy does not end up getting used.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg KH <greg@kroah.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Jann Horn <jann@thejh.net>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Helge Deller <deller@gmx.de>

One of the debian buildd servers had this crash in the syslog without
any other information:

 Unaligned handler failed, ret = -2
 clock_adjtime (pid 22578): Unaligned data reference (code 28)
 CPU: 1 PID: 22578 Comm: clock_adjtime Tainted: G  E  4.5.0-2-parisc64-smp #1 Debian 4.5.4-1
 task: 000000007d9960f8 ti: 00000001bde7c000 task.ti: 00000001bde7c000

      YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
 PSW: 00001000000001001111100000001111 Tainted: G            E
 r00-03  000000ff0804f80f 00000001bde7c2b0 00000000402d2be8 00000001bde7c2b0
 r04-07  00000000409e1fd0 00000000fa6f7fff 00000001bde7c148 00000000fa6f7fff
 r08-11  0000000000000000 00000000ffffffff 00000000fac9bb7b 000000000002b4d4
 r12-15  000000000015241c 000000000015242c 000000000000002d 00000000fac9bb7b
 r16-19  0000000000028800 0000000000000001 0000000000000070 00000001bde7c218
 r20-23  0000000000000000 00000001bde7c210 0000000000000002 0000000000000000
 r24-27  0000000000000000 0000000000000000 00000001bde7c148 00000000409e1fd0
 r28-31  0000000000000001 00000001bde7c320 00000001bde7c350 00000001bde7c218
 sr00-03  0000000001200000 0000000001200000 0000000000000000 0000000001200000
 sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000402d2e84 00000000402d2e88
  IIR: 0ca0d089    ISR: 0000000001200000  IOR: 00000000fa6f7fff
  CPU:        1   CR30: 00000001bde7c000 CR31: ffffffffffffffff
  ORIG_R28: 00000002369fe628
  IAOQ[0]: compat_get_timex+0x2dc/0x3c0
  IAOQ[1]: compat_get_timex+0x2e0/0x3c0
  RP(r2): compat_get_timex+0x40/0x3c0
 Backtrace:
  [<00000000402d4608>] compat_SyS_clock_adjtime+0x40/0xc0
  [<0000000040205024>] syscall_exit+0x0/0x14

This means the userspace program clock_adjtime called the clock_adjtime()
syscall and then crashed inside the compat_get_timex() function.
Syscalls should never crash programs, but instead return EFAULT.

The IIR register contains the executed instruction, which disassebles
into "ldw 0(sr3,r5),r9".
This load-word instruction is part of __get_user() which tried to read the word
at %r5/IOR (0xfa6f7fff). This means the unaligned handler jumped in.  The
unaligned handler is able to emulate all ldw instructions, but it fails if it
fails to read the source e.g. because of page fault.

The following program reproduces the problem:

#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/mman.h>

int main(void) {
        /* allocate 8k */
        char *ptr = mmap(NULL, 2*4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
        /* free second half (upper 4k) and make it invalid. */
        munmap(ptr+4096, 4096);
        /* syscall where first int is unaligned and clobbers into invalid memory region */
        /* syscall should return EFAULT */
        return syscall(__NR_clock_adjtime, 0, ptr+4095);
}

To fix this issue we simply need to check if the faulting instruction address
is in the exception fixup table when the unaligned handler failed. If it
is, call the fixup routine instead of crashing.

While looking at the unaligned handler I found another issue as well: The
target register should not be modified if the handler was unsuccessful.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org

Avoid showing invalid printk time stamps during boot.
Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Aaro Koskinen <aaro.koskinen@iki.fi>

This patch fixes backtrace on PA-RISC

There were several problems:

1) The code that decodes instructions handles instructions that subtract
from the stack pointer incorrectly. If the instruction subtracts the
number X from the stack pointer the code increases the frame size by
(0x100000000-X).  This results in invalid accesses to memory and
recursive page faults.

2) Because gcc reorders blocks, handling instructions that subtract from
the frame pointer is incorrect. For example, this function
	int f(int a)
	{
		if (__builtin_expect(a, 1))
			return a;
		g();
		return a;
	}
is compiled in such a way, that the code that decreases the stack
pointer for the first "return a" is placed before the code for "g" call.
If we recognize this decrement, we mistakenly believe that the frame
size for the "g" call is zero.

To fix problems 1) and 2), the patch doesn't recognize instructions that
decrease the stack pointer at all. To further safeguard the unwind code
against nonsense values, we don't allow frame size larger than
Total_frame_size.

3) The backtrace is not locked. If stack dump races with module unload,
invalid table can be accessed.

This patch adds a spinlock when processing module tables.

Note, that for correct backtrace, you need recent binutils.
Binutils 2.18 from Debian 5 produce garbage unwind tables.
Binutils 2.21 work better (it sometimes forgets function frames, but at
least it doesn't generate garbage).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Helge Deller <deller@gmx.de>

Pull drm fixes from Dave Airlie:
 "A bunch of ARM drivers got into the fixes vibe this time around, so
  this contains a bunch of fixes for imx, atmel hlcdc, arm hdlcd (only
  so many combos of hlcd), mediatek and omap drm.

  Other than that there is one mgag200 fix and a few core drm regression
  fixes"

* tag 'drm-fixes-for-v4.7-rc2' of git://people.freedesktop.org/~airlied/linux: (34 commits)
  drm/omap: fix unused variable warning.
  drm: hdlcd: Add information about the underlying framebuffers in debugfs
  drm: hdlcd: Cleanup the atomic plane operations
  drm/hdlcd: Fix up crtc_state->event handling
  drm: hdlcd: Revamp runtime power management
  drm/mediatek: mtk_dsi: Remove spurious drm_connector_unregister
  drm/mediatek: mtk_dpi: remove invalid error message
  drm: atmel-hlcdc: fix a NULL check
  drm: atmel-hlcdc: fix atmel_hlcdc_crtc_reset() implementation
  drm/mgag200: Black screen fix for G200e rev 4
  drm: Wrap direct calls to driver->gem_free_object from CMA
  drm: fix fb refcount issue with atomic modesetting
  drm: make drm_atomic_set_mode_prop_for_crtc() more reliable
  drm/sti: remove extra mode fixup
  drm: add missing drm_mode_set_crtcinfo call
  drm/omap: include gpio/consumer.h where needed
  drm/omap: include linux/seq_file.h where needed
  Revert "drm/omap: no need to select OMAP2_DSS"
  drm/omap: Remove regulator API abuse
  OMAPDSS: HDMI5: Change DDC timings
  ...

Pull VFIO fixes from Alex Williamson:
 "Fix irqfd shutdown ordering, build warning, and VPD short read"

* tag 'vfio-v4.7-rc2' of git://github.com/awilliam/linux-vfio:
  vfio/pci: Allow VPD short read
  vfio/type1: Fix build warning
  vfio/pci: Fix ordering of eventfd vs virqfd shutdown

Pull MMC fixes from Ulf Hansson:
 "MMC core:
   - Fix/restore behaviour when selecting bus width for (e)MMC

  MMC host:
   - sunxi: Fix eMMC HS-DDR modes on Allwinner A80"

* tag 'mmc-v4.7-rc1-2' of git://git.linaro.org/people/ulf.hansson/mmc:
  mmc: sunxi: Re-enable eMMC HS-DDR modes on Allwinner A80
  mmc: sunxi: Fix DDR MMC timings for A80
  mmc: fix mmc mode selection for HS-DDR and higher

Pull btrfs fixes from Chris Mason:
 "The important part of this pull is Filipe's set of fixes for btrfs
  device replacement.  Filipe fixed a few issues seen on the list and a
  number he found on his own"

* 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: deal with duplciates during extent_map insertion in btrfs_get_extent
  Btrfs: fix race between device replace and read repair
  Btrfs: fix race between device replace and discard
  Btrfs: fix race between device replace and chunk allocation
  Btrfs: fix race setting block group back to RW mode during device replace
  Btrfs: fix unprotected assignment of the left cursor for device replace
  Btrfs: fix race setting block group readonly during device replace
  Btrfs: fix race between device replace and block group removal
  Btrfs: fix race between readahead and device replace/removal

Pull Ceph fixes from Sage Weil:
 "We have a few follow-up fixes for the libceph refactor from Ilya, and
  then some cephfs + fscache fixes from Zheng.

  The first two FS-Cache patches are acked by David Howells and deemed
  trivial enough to go through our tree.  The rest fix some issues with
  the ceph fscache handling (disable cache for inodes opened for write,
  and simplify the revalidation logic accordingly, dropping the
  now-unnecessary work queue)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: use i_version to check validity of fscache
  ceph: improve fscache revalidation
  ceph: disable fscache when inode is opened for write
  ceph: avoid unnecessary fscache invalidation/revlidation
  ceph: call __fscache_uncache_page() if readpages fails
  FS-Cache: make check_consistency callback return int
  FS-Cache: wake write waiter after invalidating writes
  libceph: use %s instead of %pE in dout()s
  libceph: put request only if it's done in handle_reply()
  libceph: change ceph_osdmap_flag() to take osdc

Pull ACPI fixes from Rafael Wysocki:
 "Two fixes for problems introduced recently (ACPICA and the ACPI
  backlight driver) and one fix for an older issue that prevents at
  least one system from booting.

  Specifics:

   - Fix an incorrect check introduced by recent ACPICA changes which
     causes problems with booting KVM guests to happen, among other
     things (Lv Zheng).

   - Fix a backlight issue introduced by recent changes to the ACPI
     video driver (Aaron Lu).

   - Fix the ACPI processor initialization which attempts to register an
     IO region without checking if that really is necessary and
     sometimes prevents drivers loaded subsequently from registering
     their resources which leads to boot issues (Rafael Wysocki)"

* tag 'acpi-4.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / processor: Avoid reserving IO regions too early
  ACPICA / Hardware: Fix old register check in acpi_hw_get_access_bit_width()
  ACPI / Thermal / video: fix max_level incorrect value

Pull power management fixes from Rafael Wysocki:
 "Two fixes for problems introduced recently in the cpufreq core and the
  intel_pstate driver.

  Specifics:

   - Fix a silly mistake related to the clamp_val() usage in a function
     added by a recent commit (Rafael Wysocki).

   - Reduce the log level of an annoying message added to intel_pstate
     during the recent merge window (Srinivas Pandruvada)"

* tag 'pm-4.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: Fix clamp_val() usage in cpufreq_driver_fast_switch()
  cpufreq: intel_pstate: Downgrade print level for _PPC

Merge various fixes from Andrew Morton:
 "10 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm, page_alloc: recalculate the preferred zoneref if the context can ignore memory policies
  mm, page_alloc: reset zonelist iterator after resetting fair zone allocation policy
  mm, oom_reaper: do not use siglock in try_oom_reaper()
  mm, page_alloc: prevent infinite loop in buffered_rmqueue()
  checkpatch: reduce git commit description style false positives
  mm/z3fold.c: avoid modifying HEADLESS page and minor cleanup
  memcg: add RCU locking around css_for_each_descendant_pre() in memcg_offline_kmem()
  mm: check the return value of lookup_page_ext for all call sites
  kdump: fix dmesg gdbmacro to work with record based printk
  mm: fix overflow in vm_map_ram()

Pull irq fixes from Thomas Gleixner:
 - a few simple fixes for fallout from the recent gic-v3 changes
 - a workaround for a Cavium thunderX erratum
 - a bugfix for the pic32 irqchip to make external interrupts work proper
 - a missing return value in the generic IPI management code

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/irq-pic32-evic: Fix bug with external interrupts.
  irqchip/gicv3-its: numa: Enable workaround for Cavium thunderx erratum 23144
  irqchip/gic-v3: Fix quiescence check in gic_enable_redist
  irqchip/gic-v3: Fix copy+paste mistakes in defines
  irqchip/gic-v3: Fix ICC_SGI1R_EL1.INTID decoding mask
  genirq: Fix missing return value in irq_destroy_ipi()

The optimistic fast path may use cpuset_current_mems_allowed instead of
of a NULL nodemask supplied by the caller for cpuset allocations.  The
preferred zone is calculated on this basis for statistic purposes and as
a starting point in the zonelist iterator.

However, if the context can ignore memory policies due to being atomic
or being able to ignore watermarks then the starting point in the
zonelist iterator is no longer correct.  This patch resets the zonelist
iterator in the allocator slowpath if the context can ignore memory
policies.  This will alter the zone used for statistics but only after
it is known that it makes sense for that context.  Resetting it before
entering the slowpath would potentially allow an ALLOC_CPUSET allocation
to be accounted for against the wrong zone.  Note that while nodemask is
not explicitly set to the original nodemask, it would only have been
overwritten if cpuset_enabled() and it was reset before the slowpath was
entered.

Link: http://lkml.kernel.org/r/20160602103936.GU2527@techsingularity.net
Fixes: c33d6c06 ("mm, page_alloc: avoid looking up the first zone in a zonelist twice")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Geert Uytterhoeven reported the following problem that bisected to
commit c33d6c06 ("mm, page_alloc: avoid looking up the first zone
in a zonelist twice") on m68k/ARAnyM

    BUG: scheduling while atomic: cron/668/0x10c9a0c0
    Modules linked in:
    CPU: 0 PID: 668 Comm: cron Not tainted 4.6.0-atari-05133-gc33d6c06 #364
    Call Trace: [<0003d7d0>] __schedule_bug+0x40/0x54
      __schedule+0x312/0x388
      __schedule+0x0/0x388
      prepare_to_wait+0x0/0x52
      schedule+0x64/0x82
      schedule_timeout+0xda/0x104
      set_next_entity+0x18/0x40
      pick_next_task_fair+0x78/0xda
      io_schedule_timeout+0x36/0x4a
      bit_wait_io+0x0/0x40
      bit_wait_io+0x12/0x40
      __wait_on_bit+0x46/0x76
      wait_on_page_bit_killable+0x64/0x6c
      bit_wait_io+0x0/0x40
      wake_bit_function+0x0/0x4e
      __lock_page_or_retry+0xde/0x124
      do_scan_async+0x114/0x17c
      lookup_swap_cache+0x24/0x4e
      handle_mm_fault+0x626/0x7de
      find_vma+0x0/0x66
      down_read+0x0/0xe
      wait_on_page_bit_killable_timeout+0x77/0x7c
      find_vma+0x16/0x66
      do_page_fault+0xe6/0x23a
      res_func+0xa3c/0x141a
      buserr_c+0x190/0x6d4
      res_func+0xa3c/0x141a
      buserr+0x20/0x28
      res_func+0xa3c/0x141a
      buserr+0x20/0x28

The relationship is not obvious but it's due to a failure to rescan the
full zonelist after the fair zone allocation policy exhausts the batch
count.  While this is a functional problem, it's also a performance
issue.  A page allocator microbenchmark showed the following

                                   4.7.0-rc1                  4.7.0-rc1
                                     vanilla                 reset-v1r2
  Min      alloc-odr0-1     327.00 (  0.00%)           326.00 (  0.31%)
  Min      alloc-odr0-2     235.00 (  0.00%)           235.00 (  0.00%)
  Min      alloc-odr0-4     198.00 (  0.00%)           198.00 (  0.00%)
  Min      alloc-odr0-8     170.00 (  0.00%)           170.00 (  0.00%)
  Min      alloc-odr0-16    156.00 (  0.00%)           156.00 (  0.00%)
  Min      alloc-odr0-32    150.00 (  0.00%)           150.00 (  0.00%)
  Min      alloc-odr0-64    146.00 (  0.00%)           146.00 (  0.00%)
  Min      alloc-odr0-128   145.00 (  0.00%)           145.00 (  0.00%)
  Min      alloc-odr0-256   155.00 (  0.00%)           155.00 (  0.00%)
  Min      alloc-odr0-512   168.00 (  0.00%)           165.00 (  1.79%)
  Min      alloc-odr0-1024  175.00 (  0.00%)           174.00 (  0.57%)
  Min      alloc-odr0-2048  180.00 (  0.00%)           180.00 (  0.00%)
  Min      alloc-odr0-4096  187.00 (  0.00%)           186.00 (  0.53%)
  Min      alloc-odr0-8192  190.00 (  0.00%)           190.00 (  0.00%)
  Min      alloc-odr0-16384 191.00 (  0.00%)           191.00 (  0.00%)
  Min      alloc-odr1-1     736.00 (  0.00%)           445.00 ( 39.54%)
  Min      alloc-odr1-2     343.00 (  0.00%)           335.00 (  2.33%)
  Min      alloc-odr1-4     277.00 (  0.00%)           270.00 (  2.53%)
  Min      alloc-odr1-8     238.00 (  0.00%)           233.00 (  2.10%)
  Min      alloc-odr1-16    224.00 (  0.00%)           218.00 (  2.68%)
  Min      alloc-odr1-32    210.00 (  0.00%)           208.00 (  0.95%)
  Min      alloc-odr1-64    207.00 (  0.00%)           203.00 (  1.93%)
  Min      alloc-odr1-128   276.00 (  0.00%)           202.00 ( 26.81%)
  Min      alloc-odr1-256   206.00 (  0.00%)           202.00 (  1.94%)
  Min      alloc-odr1-512   207.00 (  0.00%)           202.00 (  2.42%)
  Min      alloc-odr1-1024  208.00 (  0.00%)           205.00 (  1.44%)
  Min      alloc-odr1-2048  213.00 (  0.00%)           212.00 (  0.47%)
  Min      alloc-odr1-4096  218.00 (  0.00%)           216.00 (  0.92%)
  Min      alloc-odr1-8192  341.00 (  0.00%)           219.00 ( 35.78%)

Note that order-0 allocations are unaffected but higher orders get a
small boost from this patch and a large reduction in system CPU usage
overall as can be seen here:

             4.7.0-rc1   4.7.0-rc1
               vanilla  reset-v1r2
  User           85.32       86.31
  System       2221.39     2053.36
  Elapsed      2368.89     2202.47

Fixes: c33d6c06 ("mm, page_alloc: avoid looking up the first zone in a zonelist twice")
Link: http://lkml.kernel.org/r/20160531100848.GR2527@techsingularity.netSigned-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Oleg has noted that siglock usage in try_oom_reaper is both pointless
and dangerous.  signal_group_exit can be checked lockless.  The problem
is that sighand becomes NULL in __exit_signal so we can crash.

Fixes: 3ef22dff ("oom, oom_reaper: try to reap tasks which skip regular OOM killer path")
Link: http://lkml.kernel.org/r/1464679423-30218-1-git-send-email-mhocko@kernel.orgSigned-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In DEBUG_VM kernel, we can hit infinite loop for order == 0 in
buffered_rmqueue() when check_new_pcp() returns 1, because the bad page
is never removed from the pcp list.  Fix this by removing the page
before retrying.  Also we don't need to check if page is non-NULL,
because we simply grab it from the list which was just tested for being
non-empty.

Fixes: 479f854a ("mm, page_alloc: defer debugging checks of pages allocated from the PCP")
Link: http://lkml.kernel.org/r/20160530090154.GM2527@techsingularity.netSigned-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Some lines in a commit log appear to be commit SHA1 ids like:

  ERROR: Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")' - ie: 'commit 0123456789ab ("commit description")'
  Link: http://lkml.kernel.org/r/40e03fd7aaf1f55c75d787128d6d17c5a71226c2.1464358556.git.vdavydov@virtuozzo.com

Reduce the false positives.

Link: http://lkml.kernel.org/r/eda977eaa8328fef42bb3c87935d97e10ea8ff67.1464384023.git.joe@perches.comSigned-off-by: Joe Perches <joe@perches.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix erroneous z3fold header access in a HEADLESS page in reclaim
function, and change one remaining direct handle-to-buddy conversion to
use the appropriate helper.

Link: http://lkml.kernel.org/r/5748706F.9020208@gmail.comSigned-off-by: Vitaly Wool <vitalywool@gmail.com>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjenning@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg_offline_kmem() may be called from memcg_free_kmem() after a css
init failure.  memcg_free_kmem() is a ->css_free callback which is
called without cgroup_mutex and memcg_offline_kmem() ends up using
css_for_each_descendant_pre() without any locking.  Fix it by adding rcu
read locking around it.

    mkdir: cannot create directory `65530': No space left on device
    ===============================
    [ INFO: suspicious RCU usage. ]
    4.6.0-work+ #321 Not tainted
    -------------------------------
    kernel/cgroup.c:4008 cgroup_mutex or RCU read lock required!
     [  527.243970] other info that might help us debug this:
     [  527.244715]
    rcu_scheduler_active = 1, debug_locks = 0
    2 locks held by kworker/0:5/1664:
     #0:  ("cgroup_destroy"){.+.+..}, at: [<ffffffff81060ab5>] process_one_work+0x165/0x4a0
     #1:  ((&css->destroy_work)#3){+.+...}, at: [<ffffffff81060ab5>] process_one_work+0x165/0x4a0
     [  527.248098] stack backtrace:
    CPU: 0 PID: 1664 Comm: kworker/0:5 Not tainted 4.6.0-work+ #321
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.1-1.fc24 04/01/2014
    Workqueue: cgroup_destroy css_free_work_fn
    Call Trace:
      dump_stack+0x68/0xa1
      lockdep_rcu_suspicious+0xd7/0x110
      css_next_descendant_pre+0x7d/0xb0
      memcg_offline_kmem.part.44+0x4a/0xc0
      mem_cgroup_css_free+0x1ec/0x200
      css_free_work_fn+0x49/0x5e0
      process_one_work+0x1c5/0x4a0
      worker_thread+0x49/0x490
      kthread+0xea/0x100
      ret_from_fork+0x1f/0x40

Link: http://lkml.kernel.org/r/20160526203018.GG23194@mtj.duckdns.orgSigned-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>	[4.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull timer bugfix from Thomas Gleixner:
 "A single bugfix for the error check wreckage we introduced in the
  merge window"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  time: Make settimeofday error checking work again

Per the discussion with Joonsoo Kim [1], we need check the return value
of lookup_page_ext() for all call sites since it might return NULL in
some cases, although it is unlikely, i.e.  memory hotplug.

Tested with ltp with "page_owner=0".

[1] http://lkml.kernel.org/r/20160519002809.GA10245@js1304-P5Q-DELUXE

[akpm@linux-foundation.org: fix build-breaking typos]
[arnd@arndb.de: fix build problems from lookup_page_ext]
  Link: http://lkml.kernel.org/r/6285269.2CksypHdYp@wuerfel
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1464023768-31025-1-git-send-email-yang.shi@linaro.orgSigned-off-by: Yang Shi <yang.shi@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 7ff9554b ("printk: convert byte-buffer to variable-length
record buffer") introduced a record based printk buffer.  Modify
gdbmacros.txt to parse this new structure so dmesg will work properly.

Link: http://lkml.kernel.org/r/1463515794-1599-1-git-send-email-minyard@acm.orgSigned-off-by: Corey Minyard <cminyard@mvista.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When remapping pages accounting for 4G or more memory space, the
operation 'count << PAGE_SHIFT' overflows as it is performed on an
integer.  Solution: cast before doing the bitshift.

[akpm@linux-foundation.org: fix vm_unmap_ram() also]
[akpm@linux-foundation.org: fix vmap() as well, per Guillermo]
Link: http://lkml.kernel.org/r/etPan.57175fb3.7a271c6b.2bd@naudit.esSigned-off-by: Guillermo Julián Moreno <guillermo.julian@naudit.es>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull ARM fix from Russell King:
 "Just one fix to the ptrace code, spotted by Simon Marchi, where if a
  thread migrates to a different CPU and the VFP registers are changed
  through ptrace, the application doesn't see the updated VFP registers"

* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: fix PTRACE_SETVFPREGS on SMP systems