Remove support for the "pci=firmware" command line parameter, which was
way to keep the kernel from changing any PCI BAR assignments.  This was
copied from ARM, but is not actually needed on unicore32.

The corresponding ARM support was removed by 903589ca ("ARM: 8554/1:
kernel: pci: remove pci=firmware command line parameter handling").
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

On systems with PCI_PROBE_ONLY set, we rely on BAR assignments from
firmware.  Previously we did not insert those resources into the resource
tree, so we had to skip pci_enable_resources() because it fails if
resources are not in the resource tree.

Now that we *do* insert resources even when PCI_PROBE_ONLY is set, we no
longer need the ARM-specific pcibios_enable_device().  Remove it so we
use the generic version.

[bhelgaas: changelog]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Russell King <linux@arm.linux.org.uk>

On systems with PCI_PROBE_ONLY set, we rely on BAR assignments from
firmware.  Previously we did not insert those resources into the resource
tree, so we had to skip pci_enable_resources() because it fails if
resources are not in the resource tree.

Now that we *do* insert resources even when PCI_PROBE_ONLY is set, we no
longer need the ARM64-specific pcibios_enable_device().  Remove it so we
use the generic version.

[bhelgaas: changelog]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Catalin Marinas <catalin.marinas@arm.com>

We claim PCI BAR and bridge window resources in pci_bus_assign_resources(),
but when PCI_PROBE_ONLY is set, we treat those resources as immutable and
don't call pci_bus_assign_resources(), so the resources aren't put in the
resource tree.

When the resources aren't in the tree, they don't show up in /proc/iomem,
we can't detect conflicts, and we need special cases elsewhere for
PCI_PROBE_ONLY or resources without a parent pointer.

Claim all PCI BAR and window resources in the PCI_PROBE_ONLY case.

If a PCI_PROBE_ONLY platform assigns conflicting resources, Linux can't fix
the conflicts.  Previously we didn't notice the conflicts, but now we will,
which may expose new failures.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

We claim PCI BAR and bridge window resources in pci_bus_assign_resources(),
but when PCI_PROBE_ONLY is set, we treat those resources as immutable and
don't call pci_bus_assign_resources(), so the resources aren't put in the
resource tree.

When the resources aren't in the tree, they don't show up in /proc/iomem,
we can't detect conflicts, and we need special cases elsewhere for
PCI_PROBE_ONLY or resources without a parent pointer.

Claim all PCI BAR and window resources in the PCI_PROBE_ONLY case.

If a PCI_PROBE_ONLY platform assigns conflicting resources, Linux can't fix
the conflicts.  Previously we didn't notice the conflicts, but now we will,
which may expose new failures.

[bhelgaas: changelog, add resource comment, remove size/assign comments]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Russell King <linux@armlinux.org.uk>

We claim PCI BAR and bridge window resources in pci_bus_assign_resources(),
but when PCI_PROBE_ONLY is set, we treat those resources as immutable and
don't call pci_bus_assign_resources(), so the resources aren't put in the
resource tree.

When the resources aren't in the tree, they don't show up in /proc/iomem,
we can't detect conflicts, and we need special cases elsewhere for
PCI_PROBE_ONLY or resources without a parent pointer.

Claim all PCI BAR and window resources in the PCI_PROBE_ONLY case.

If a PCI_PROBE_ONLY platform assigns conflicting resources, Linux can't fix
the conflicts.  Previously we didn't notice the conflicts, but now we will,
which may expose new failures.

[bhelgaas: changelog, summarize comment]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: David Daney <david.daney@cavium.com>

All PCI resources (bridge windows and BARs) should be inserted in the
iomem_resource and ioport_resource trees so we know what space is occupied
and what is available for other devices.  There's nothing arch-specific
about this, but it is currently done by arch-specific code.

Add a generic pci_bus_claim_resources() interface so we can migrate away
from the arch-specific code.

[bhelgaas: changelog]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Yinghai Lu <yinghai@kernel.org>

Now that we do have pci_request_mem_regions() and pci_release_mem_regions()
at hand, use it in the ethernet drivers.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
CC: Jay Cliburn <jcliburn@gmail.com>
CC: Chris Snook <chris.snook@gmail.com>
CC: David S. Miller <davem@davemloft.net>

Now that we do have pci_request_mem_regions() and pci_release_mem_regions()
at hand, use it in the Intel ethernet drivers.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
CC: David S. Miller <davem@davemloft.net>

Now that we do have pci_request_mem_regions() and pci_release_mem_regions()
at hand, use it in the genwqe driver.

[bhelgaas: fix build issues]
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
CC: Frank Haverkamp <haver@linux.vnet.ibm.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that we do have pci_request_mem_regions() and pci_release_mem_regions()
at hand, use it in the lpfc driver.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dick Kennedy <dick.kennedy@broadcom.com>
CC: James Smart <james.smart@avagotech.com>
CC: James E.J. Bottomley <jejb@linux.vnet.ibm.com>
CC: Martin K. Petersen <martin.petersen@oracle.com>

Now that we do have pci_request_mem_regions() and pci_release_mem_regions()
at hand, use it in the NVMe driver.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
CC: Keith Busch <keith.busch@intel.com>
CC: Jens Axboe <axboe@fb.com>

Add helpers to request and release a device's memory or I/O regions.

With these helpers in place, one does not need to select a device's memory
or I/O regions with pci_select_bars() prior to requesting or releasing
them.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Some uio-based PCI drivers, e.g., uio_cif do not work if the assigned PCI
memory resources are not page aligned.

By using the kernel option "pci=resource_alignment" it is possible to force
single PCI boards to use page alignment for their memory resources.
However, this is fairly cumbersome if several of these boards are in use
as the specification of the cards has to be done via PCI bus/slot/function
number which might change, e.g., by adding another board.

Extend the kernel option "pci=resource_alignment" to allow specification of
relevant devices via PCI device/vendor (and subdevice/subvendor) IDs.  The
specification of the devices via device/vendor is indicated by a leading
string "pci:" as argument to "pci=resource_alignment".  The format of the
specification is pci:<vendor>:<device>[:<subvendor>:<subdevice>]
Signed-off-by: Mathias Koehrer <mathias.koehrer@etas.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

"User" addresses are shown in /sys/devices/pci.../.../resource and
/proc/bus/pci/devices and used as mmap offsets for /proc/bus/pci/BB/DD.F
files.  On sparc, these are PCI bus addresses, i.e., raw BAR values.

Previously pci_resource_to_user() computed the user address by
subtracting either pbm->io_space.start or pbm->mem_space.start from the
resource start.

We've already told the PCI core about those offsets here:

  pci_scan_one_pbm()
    pci_add_resource_offset(&resources, &pbm->io_space, pbm->io_space.start);
    pci_add_resource_offset(&resources, &pbm->mem_space, pbm->mem_space.start);
    pci_add_resource_offset(&resources, &pbm->mem64_space, pbm->mem_space.start);

so pcibios_resource_to_bus() knows how to do that translation.

No functional change intended.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>

"User" addresses are shown in /sys/devices/pci.../.../resource and
/proc/bus/pci/devices and used as mmap offsets for /proc/bus/pci/BB/DD.F
files.  For I/O port resources on powerpc, these are PCI bus addresses,
i.e., raw BAR values.

Previously pci_resource_to_user() computed the user address by subtracting
"hose->io_base_virt - _IO_BASE" from the resource start:

  pci_resource_to_user()
    if (IO)
      offset = (unsigned long)hose->io_base_virt - _IO_BASE;
    *start = rsrc->start - offset;

We've already told the PCI core about that "hose->io_base_virt - _IO_BASE"
offset:

  pcibios_setup_phb_resources()
    res = &hose->io_resource;
    offset = pcibios_io_space_offset();
    /* i.e., "offset = hose->io_base_virt - _IO_BASE" */
    pci_add_resource_offset(resources, res, offset);

so pcibios_resource_to_bus() knows how to do that translation.

No functional change intended.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>

"User" addresses are shown in /sys/devices/pci.../.../resource and
/proc/bus/pci/devices and used as mmap offsets for /proc/bus/pci/BB/DD.F
files.  For I/O port resources on microblaze, these are PCI bus addresses,
i.e., raw BAR values.

Previously pci_resource_to_user() computed the user address by subtracting
"hose->io_base_virt - _IO_BASE" from the resource start:

  pci_resource_to_user()
    if (IO)
      offset = (unsigned long)hose->io_base_virt - _IO_BASE;
    *start = rsrc->start - offset;

We've already told the PCI core about that "hose->io_base_virt - _IO_BASE"
offset:

  pcibios_setup_phb_resources()
    res = &hose->io_resource;
    pci_add_resource_offset(resources, res, hose->io_base_virt - _IO_BASE);

so pcibios_resource_to_bus() knows how to do that translation.

No functional change intended.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>

Replace the pci_resource_to_user() declarations in each arch that defines
HAVE_ARCH_PCI_RESOURCE_TO_USER with a single one in linux/pci.h.

Change the MIPS static inline implementation to a non-inline version so the
static inline doesn't conflict with the new non-static linux/pci.h
declaration.

No functional change intended.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

The microblaze __pci_mmap_set_pgprot() was apparently copied from powerpc,
where it computes either an uncacheable pgprot_t or a write-combining one.
But on microblaze, we always use the regular uncacheable pgprot_t.

Remove the useless code in __pci_mmap_set_pgprot() and inline it at the
only call site.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>

The powerpc-specific __pci_mmap_set_pgprot() does two things:

  1) Disables write combining for I/O port space mappings

     This only affects procfs mappings.  The pci_mmap_resource() sysfs path
     only requests write combining for resources with IORESOURCE_PREFETCH
     set, which doesn't include I/O resources.

     The only way to request write combining for I/O port space mappings
     was via the PCIIOC_WRITE_COMBINE ioctl and the proc_bus_pci_mmap()
     path, and we recently changed that path to ignore write combining for
     I/O, so this code in powerpc is no longer needed.

  2) Automatically enables write combining for mappings of prefetchable
     resources, even if not requested by the user

     Both procfs (via PCIIOC_MMAP_IS_MEM and PCIIOC_WRITE_COMBINE ioctls)
     and sysfs (via "resourceN_wc" files, which are created for resources
     with IORESOURCE_PREFETCH) provide ways for the user to map PCI memory
     space with write combining.

     Users that desire write combining should use one of those ways instead
     of relying on powerpc-specific behavior.

Remove the powerpc-specific __pci_mmap_set_pgprot().

The user-visible effect of this change is that powerpc users mapping
prefetchable PCI memory space via procfs without PCIIOC_WRITE_COMBINE or
via sysfs "resourceN" (not "resourceN_wc") will get regular uncacheable
mappings instead of the write combining mappings they used to get.

The new behavior matches the behavior on all other arches that support
write combining mapping.

[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI exposes files like /proc/bus/pci/00/00.0 in procfs.  These files
support operations like this:

  ioctl(fd, PCIIOC_MMAP_IS_IO);           # request I/O port space
  ioctl(fd, PCIIOC_WRITE_COMBINE, 1);     # request write-combining
  mmap(fd, ...)

Write combining is useful on PCI memory space, but I don't think it makes
sense on PCI I/O port space.

We *could* change proc_bus_pci_ioctl() to make it impossible to set
mmap_state == pci_mmap_io and write_combine at the same time, but that
would break the following sequence, which is currently legal:

  mmap(fd, ...)                           # default is I/O, non-combining
  ioctl(fd, PCIIOC_WRITE_COMBINE, 1);     # request write-combining
  ioctl(fd, PCIIOC_MMAP_IS_MEM);          # request memory space
  mmap(fd, ...)                           # get write-combining mapping

Ignore the write-combining flag when mapping I/O port space.

This patch should have no functional effect, based on this analysis of all
implementations of pci_mmap_page_range():

  - ia64 mips parisc sh unicore32 x86 do not support mapping of I/O port
    space at all.

  - arm cris microblaze mn10300 sparc xtensa support mapping of I/O port
    space, but ignore the write_combine argument to pci_mmap_page_range().

  - powerpc supports mapping of I/O port space and uses write_combine, and
    it disables write combining for I/O port space in
    __pci_mmap_set_pgprot().

This patch makes it possible to remove __pci_mmap_set_pgprot() from
powerpc, which simplifies that path.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.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>