If we overflow the stack into a guard page, we'll recursively fault
when trying to dump the contents of the guard page.  Use
probe_kernel_address() so we can recover if this happens.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/e626d47a55d7b04dcb1b4d33faa95e8505b217c8.1468527351.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

If we overflow the stack, print_context_stack() will abort.  Detect
this case and rewind back into the valid part of the stack so that
we can trace it.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/ee1690eb2715ccc5dc187fde94effa4ca0ccbbcd.1468527351.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

kernel_unmap_pages_in_pgd() is dangerous: if a PGD entry in
init_mm.pgd were to be cleared, callers would need to ensure that
the pgd entry hadn't been propagated to any other pgd.

Its only caller was efi_cleanup_page_tables(), and that, in turn,
was unused, so just delete both functions.  This leaves a couple of
other helpers unused, so delete them, too.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/77ff20fdde3b75cd393be5559ad8218870520248.1468527351.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

This avoids pointless races in which another CPU or task might see a
partially populated global PGD entry.  These races should normally
be harmless, but, if another CPU propagates the entry via
vmalloc_fault() and then populate_pgd() fails (due to memory allocation
failure, for example), this prevents a use-after-free of the PGD
entry.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/bf99df27eac6835f687005364bd1fbd89130946c.1468527351.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

So when memory hotplug removes a piece of physical memory from pagetable
mappings, it also frees the underlying PGD entry.

This complicates PGD management, so don't do this. We can keep the
PGD mapped and the PUD table all clear - it's only a single 4K page
per 512 GB of memory hotplugged.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/064ff6c7275734537f969e876f6cd0baa954d2cc.1468527351.git.luto@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

 Conflicts:
	tools/testing/selftests/x86/Makefile
Signed-off-by: Ingo Molnar <mingo@kernel.org>

The page table manipulation code seems to have grown a couple of
sites that are looking for empty PTEs.  Just in case one of these
entries got a stray bit set, use pte_none() instead of checking
for a zero pte_val().

The use pte_same() makes me a bit nervous.  If we were doing a
pte_same() check against two cleared entries and one of them had
a stray bit set, it might fail the pte_same() check.  But, I
don't think we ever _do_ pte_same() for cleared entries.  It is
almost entirely used for checking for races in fault-in paths.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: dave.hansen@intel.com
Cc: linux-mm@kvack.org
Cc: mhocko@suse.com
Link: http://lkml.kernel.org/r/20160708001915.813703D9@viggo.jf.intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

The Intel(R) Xeon Phi(TM) Processor x200 Family (codename: Knights
Landing) has an erratum where a processor thread setting the Accessed
or Dirty bits may not do so atomically against its checks for the
Present bit.  This may cause a thread (which is about to page fault)
to set A and/or D, even though the Present bit had already been
atomically cleared.

These bits are truly "stray".  In the case of the Dirty bit, the
thread associated with the stray set was *not* allowed to write to
the page.  This means that we do not have to launder the bit(s); we
can simply ignore them.

If the PTE is used for storing a swap index or a NUMA migration index,
the A bit could be misinterpreted as part of the swap type.  The stray
bits being set cause a software-cleared PTE to be interpreted as a
swap entry.  In some cases (like when the swap index ends up being
for a non-existent swapfile), the kernel detects the stray value
and WARN()s about it, but there is no guarantee that the kernel can
always detect it.

When we have 64-bit PTEs (64-bit mode or 32-bit PAE), we were able
to move the swap PTE format around to avoid these troublesome bits.
But, 32-bit non-PAE is tight on bits.  So, disallow it from running
on this hardware.  I can't imagine anyone wanting to run 32-bit
non-highmem kernels on this hardware, but disallowing them from
running entirely is surely the safe thing to do.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: dave.hansen@intel.com
Cc: linux-mm@kvack.org
Cc: mhocko@suse.com
Link: http://lkml.kernel.org/r/20160708001914.D0B50110@viggo.jf.intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

The erratum we are fixing here can lead to stray setting of the
A and D bits.  That means that a pte that we cleared might
suddenly have A/D set.  So, stop considering those bits when
determining if a pte is pte_none().  The same goes for the
other pmd_none() and pud_none().  pgd_none() can be skipped
because it is not affected; we do not use PGD entries for
anything other than pagetables on affected configurations.

This adds a tiny amount of overhead to all pte_none() checks.
I doubt we'll be able to measure it anywhere.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: dave.hansen@intel.com
Cc: linux-mm@kvack.org
Cc: mhocko@suse.com
Link: http://lkml.kernel.org/r/20160708001912.5216F89C@viggo.jf.intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

This erratum can result in Accessed/Dirty getting set by the hardware
when we do not expect them to be (on !Present PTEs).

Instead of trying to fix them up after this happens, we just
allow the bits to get set and try to ignore them.  We do this by
shifting the layout of the bits we use for swap offset/type in
our 64-bit PTEs.

It looks like this:

 bitnrs: |     ...            | 11| 10|  9|8|7|6|5| 4| 3|2|1|0|
 names:  |     ...            |SW3|SW2|SW1|G|L|D|A|CD|WT|U|W|P|
 before: |         OFFSET (9-63)          |0|X|X| TYPE(1-5) |0|
  after: | OFFSET (14-63)  |  TYPE (9-13) |0|X|X|X| X| X|X|X|0|

Note that D was already a don't care (X) even before.  We just
move TYPE up and turn its old spot (which could be hit by the
A bit) into all don't cares.

We take 5 bits away from the offset, but that still leaves us
with 50 bits which lets us index into a 62-bit swapfile (4 EiB).
I think that's probably fine for the moment.  We could
theoretically reclaim 5 of the bits (1, 2, 3, 4, 7) but it
doesn't gain us anything.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: dave.hansen@intel.com
Cc: linux-mm@kvack.org
Cc: mhocko@suse.com
Link: http://lkml.kernel.org/r/20160708001911.9A3FD2B6@viggo.jf.intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

This matches what is already done for prepare_exit_to_usermode(),
and saves about 60 clock cycles (4% speedup) with the benchmark
in the previous commit message.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/1466434712-31440-3-git-send-email-pbonzini@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

Thanks to all the work that was done by Andy Lutomirski and others,
enter_from_user_mode() and prepare_exit_to_usermode() are now called only with
interrupts disabled.  Let's provide them a version of user_enter()/user_exit()
that skips saving and restoring the interrupt flag.

On an AMD-based machine I tested this patch on, with force-enabled
context tracking, the speed-up in system calls was 90 clock cycles or 6%,
measured with the following simple benchmark:

    #include <sys/signal.h>
    #include <time.h>
    #include <unistd.h>
    #include <stdio.h>

    unsigned long rdtsc()
    {
        unsigned long result;
        asm volatile("rdtsc; shl $32, %%rdx; mov %%eax, %%eax\n"
                     "or %%rdx, %%rax" : "=a" (result) : : "rdx");
        return result;
    }

    int main()
    {
        unsigned long tsc1, tsc2;
        int pid = getpid();
        int i;

        tsc1 = rdtsc();
        for (i = 0; i < 100000000; i++)
            kill(pid, SIGWINCH);
        tsc2 = rdtsc();

        printf("%ld\n", tsc2 - tsc1);
    }
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/1466434712-31440-2-git-send-email-pbonzini@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull SCSI fixes from James Bottomley:
 "Three fixes.  One is the qla24xx MSI regression, one is a theoretical
  problem over blacklist matching, which would bite USB badly if it ever
  triggered and one is a system hang with a particular type of IPR
  device"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  qla2xxx: Fix NULL pointer deref in QLA interrupt
  SCSI: fix new bug in scsi_dev_info_list string matching
  ipr: Clear interrupt on croc/crocodile when running with LSI

Merge tag 'ecryptfs-4.7-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs

Pull eCryptfs fixes from Tyler Hicks:
 "Provide a more concise fix for CVE-2016-1583:
   - Additionally fixes linux-stable regressions caused by the
     cherry-picking of the original fix

  Some very minor changes that have queued up:
   - Fix typos in code comments
   - Remove unnecessary check for NULL before destroying kmem_cache"

* tag 'ecryptfs-4.7-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
  ecryptfs: don't allow mmap when the lower fs doesn't support it
  Revert "ecryptfs: forbid opening files without mmap handler"
  ecryptfs: fix spelling mistakes
  eCryptfs: fix typos in comment
  ecryptfs: drop null test before destroy functions

Pull IOMMU fixes from Joerg Roedel:
 "Two Fixes:

   - Intel VT-d fix for a suspend/resume issue, introduced with the
     scalability improvements in this cycle.

   - AMD IOMMU fix for systems that have unity mappings defined.  There
     was a race where translation got enabled before the unity mappings
     were in place.  This issue was seen on some HP servers"

* tag 'iommu-fixes-v4.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/amd: Fix unity mapping initialization race
  iommu/vt-d: Fix infinite loop in free_all_cpu_cached_iovas

Pull xen bug fixes from David Vrabel:

 - Fix two bugs in the handling of xenbus transactions.

 - Make the xen acpi driver compatible with Xen 4.7.

* tag 'for-linus-4.7b-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/acpi: allow xen-acpi-processor driver to load on Xen 4.7
  xenbus: simplify xenbus_dev_request_and_reply()
  xenbus: don't bail early from xenbus_dev_request_and_reply()
  xenbus: don't BUG() on user mode induced condition

Pull arm64 fixes from Will Deacon:
 "A couple of late fixes here, but one that we've been sitting on for a
  few weeks while the details were worked out.  Specifically, we now
  enforce USER_DS on taking exceptions whilst in the kernel, which
  avoids leaking kernel data to userspace through things like perf.  The
  other patch is an update to a workaround for a hardware erratum on
  some Cavium SoCs.

  Summary:

   - Enforce USER_DS on exception entry from EL1

   - Apply workaround for Cavium errata #27456 on Thunderx-81xx parts"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Enable workaround for Cavium erratum 27456 on thunderx-81xx
  arm64: kernel: Save and restore UAO and addr_limit on exception entry

Pull x86 fixes from Ingo Molnar:
 "Three fixes:

   - A boot crash fix with certain configs
   - a MAINTAINERS entry update
   - Documentation typo fixes"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/Documentation: Fix various typos in Documentation/x86/ files
  x86/amd_nb: Fix boot crash on non-AMD systems
  MAINTAINERS: Update the Calgary IOMMU entry

Pull scheduler fixes from Ingo Molnar:
 "Two load-balancing fixes for cgroups-intense workloads"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix calc_cfs_shares() fixed point arithmetics width confusion
  sched/fair: Fix effective_load() to consistently use smoothed load

Pull perf fixes from Ingo Molnar:
 "Various fixes:

   - 32-bit callgraph bug fix
   - suboptimal event group scheduling bug fix
   - event constraint fixes for Broadwell/Skylake
   - RAPL module name collision fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix pmu::filter_match for SW-led groups
  x86/perf/intel/rapl: Fix module name collision with powercap intel-rapl
  perf/x86: Fix 32-bit perf user callgraph collection
  perf/x86/intel: Update event constraints when HT is off

Pull irq fixes from Ingo Molnar:
 "Two MIPS-GIC irqchip driver fixes to unbreak certain MIPS boards"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/mips-gic: Match IPI IRQ domain by bus token only
  irqchip/mips-gic: Map to VPs using HW VPNum

Pull GPIO fixes from Linus Walleij:
 "I don't like to toss in last minute patches, but these are all for
  things that are broken, and have bitten people for real.  Two of them
  go into stable.  Maybe all of them if the compile test problem is a
  pain in the ass also for stable folks.

  Final (hopefully) GPIO fixes for v4.7:

   - Fix an oops on the Asus Eee PC 1201

   - Revert a patch trying to split GPIO parsing and GPIO configuration

   - Revert a too liberal compile testing thing"

* tag 'gpio-v4.7-5' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  Revert "gpio: gpiolib-of: Allow compile testing"
  Revert "gpiolib: Split GPIO flags parsing and GPIO configuration"
  gpio: sch: Fix Oops on module load on Asus Eee PC 1201

Pull drm fixes from Dave Airlie:
 "One nouveau fix, and a few AMD Polaris fixes and some Allwinner fixes.

  I've got some vmware fixes that I might send separate over the
  weekend, they fix some black screens, but I'm still debating them"

* tag 'drm-fixes-for-v4.7-rc7' of git://people.freedesktop.org/~airlied/linux:
  drm/amd/powerplay: Update CKS on/ CKS off voltage offset calculation.
  drm/amd/powerplay: fix bug that get wrong polaris evv voltage.
  drm/amd/powerplay: incorrectly use of the function return value
  drm/amd/powerplay: fix incorrect voltage table value for tonga
  drm/amd/powerplay: fix incorrect voltage table value for polaris10
  drm/nouveau/disp/sor/gf119: select correct sor when poking training pattern
  gpu: drm: sun4i_drv: add missing of_node_put after calling of_parse_phandle
  drm/sun4i: Send vblank event when the CRTC is disabled
  drm/sun4i: Report proper vblank

There are legitimate reasons to disallow mmap on certain files, notably
in sysfs or procfs.  We shouldn't emulate mmap support on file systems
that don't offer support natively.

CVE-2016-1583
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: stable@vger.kernel.org
[tyhicks: clean up f_op check by using ecryptfs_file_to_lower()]
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>

No need to have it appear in objdump output.

No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160708141016.GH3808@pd.tnicSigned-off-by: Ingo Molnar <mingo@kernel.org>

As of Xen 4.7 PV CPUID doesn't expose either of CPUID[1].ECX[7] and
CPUID[0x80000007].EDX[7] anymore, causing the driver to fail to load on
both Intel and AMD systems. Doing any kind of hardware capability
checks in the driver as a prerequisite was wrong anyway: With the
hypervisor being in charge, all such checking should be done by it. If
ACPI data gets uploaded despite some missing capability, the hypervisor
is free to ignore part or all of that data.

Ditch the entire check_prereq() function, and do the only valid check
(xen_initial_domain()) in the caller in its place.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

Should print this on vDSO remapping success (on new kernels):

 [root@localhost ~]# ./test_mremap_vdso_32
	AT_SYSINFO_EHDR is 0xf773f000
 [NOTE]	Moving vDSO: [f773f000, f7740000] -> [a000000, a001000]
 [OK]

Or print that mremap() for vDSOs is unsupported:

 [root@localhost ~]# ./test_mremap_vdso_32
	AT_SYSINFO_EHDR is 0xf773c000
 [NOTE]	Moving vDSO: [0xf773c000, 0xf773d000] -> [0xf7737000, 0xf7738000]
 [FAIL]	mremap() of the vDSO does not work on this kernel!
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: 0x7f454c46@gmail.com
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kselftest@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160628113539.13606-3-dsafonov@virtuozzo.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

Add possibility for 32-bit user-space applications to move
the vDSO mapping.

Previously, when a user-space app called mremap() for the vDSO
address, in the syscall return path it would land on the previous
address of the vDSOpage, resulting in segmentation violation.

Now it lands fine and returns to userspace with a remapped vDSO.

This will also fix the context.vdso pointer for 64-bit, which does
not affect the user of vDSO after mremap() currently, but this
may change in the future.

As suggested by Andy, return -EINVAL for mremap() that would
split the vDSO image: that operation cannot possibly result in
a working system so reject it.

Renamed and moved the text_mapping structure declaration inside
map_vdso(), as it used only there and now it complements the
vvar_mapping variable.

There is still a problem for remapping the vDSO in glibc
applications: the linker relocates addresses for syscalls
on the vDSO page, so you need to relink with the new
addresses.

Without that the next syscall through glibc may fail:

  Program received signal SIGSEGV, Segmentation fault.
  #0  0xf7fd9b80 in __kernel_vsyscall ()
  #1  0xf7ec8238 in _exit () from /usr/lib32/libc.so.6
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: 0x7f454c46@gmail.com
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160628113539.13606-2-dsafonov@virtuozzo.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

No need to retain a local copy of the full request message, only the
type is really needed.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xenbus_dev_request_and_reply() needs to track whether a transaction is
open.  For XS_TRANSACTION_START messages it calls transaction_start()
and for XS_TRANSACTION_END messages it calls transaction_end().

If sending an XS_TRANSACTION_START message fails or responds with an
an error, the transaction is not open and transaction_end() must be
called.

If sending an XS_TRANSACTION_END message fails, the transaction is
still open, but if an error response is returned the transaction is
closed.

Commit 027bd7e8 ("xen/xenbus: Avoid synchronous wait on XenBus
stalling shutdown/restart") introduced a regression where failed
XS_TRANSACTION_START messages were leaving the transaction open.  This
can cause problems with suspend (and migration) as all transactions
must be closed before suspending.

It appears that the problematic change was added accidentally, so just
remove it.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

Currently it's possible for broken (or malicious) userspace to flood a
kernel log indefinitely with messages a-la

	Program dmidecode tried to access /dev/mem between f0000->100000

because range_is_allowed() is case of CONFIG_STRICT_DEVMEM being turned on
dumps this information each and every time devmem_is_allowed() fails.

Reportedly userspace that is able to trigger contignuous flow of these
messages exists.

It would be possible to rate limit this message, but that'd have a
questionable value; the administrator wouldn't get information about all
the failing accessess, so then the information would be both superfluous
and incomplete at the same time :)

Returning EPERM (which is what is actually happening) is enough indication
for userspace what has happened; no need to log this particular error as
some sort of special condition.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1607081137020.24757@cbobk.fhfr.pmSigned-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull apparmor fix from James Morris.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  apparmor: fix oops, validate buffer size in apparmor_setprocattr()

Pull ACPI fixes from Rafael Wysocki:
 "All of these fix recent regressions in ACPICA, in the ACPI PCI IRQ
  management code and in the ACPI AML debugger.

  Specifics:

   - Fix a lock ordering issue in ACPICA introduced by a recent commit
     that attempted to fix a deadlock in the dynamic table loading code
     which in turn appeared after changes related to the handling of
     module-level AML also made in this cycle (Lv Zheng).

   - Fix a recent regression in the ACPI IRQ management code that may
     cause PCI drivers to be unable to register an IRQ if that IRQ
     happens to be shared with a device on the ISA bus, like the
     parallel port, by reverting one commit entirely and restoring the
     previous behavior in two other places (Sinan Kaya).

   - Fix a recent regression in the ACPI AML debugger introduced by the
     commit that removed incorrect usage of IS_ERR_VALUE() from multiple
     places (Lv Zheng)"

* tag 'acpi-4.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / debugger: Fix regression introduced by IS_ERR_VALUE() removal
  ACPICA: Namespace: Fix namespace/interpreter lock ordering
  ACPI,PCI,IRQ: separate ISA penalty calculation
  Revert "ACPI, PCI, IRQ: remove redundant code in acpi_irq_penalty_init()"
  ACPI,PCI,IRQ: factor in PCI possible

Pull power management fixes from Rafael Wysocki:
 "One fix for a recent cpuidle core change that, against all odds,
  introduced a functional regression on Power systems and the fix for
  the crash during resume from hibernation on x86-64 that has been in
  the works for the last few weeks (it actually was ready last week, but
  I wanted to allow the reporters to test if for some more time).

  Specifics:

   - Fix a recent performance regression on Power systems (powernv and
     pseries) introduced by a core cpuidle commit that decreased the
     precision of the last_residency conversion from nano- to
     microseconds, which should not matter in theory, but turned out to
     play not-so-well with the special "snooze" idle state on Power
     (Shreyas B Prabhu).

   - Fix a crash during resume from hibernation on x86-64 caused by
     possible corruption of the kernel text part of page tables in the
     last phase of image restoration exposed by a security-related
     change during the 4.3 development cycle (Rafael Wysocki)"

* tag 'pm-4.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpuidle: Fix last_residency division
  x86/power/64: Fix kernel text mapping corruption during image restoration

Merge tag 'sunxi-drm-fixes-for-4.7-2' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux into drm-fixes

Allwinner DRM driver fixes for 4.7, take 2

A new set of fixes for the sun4i driver, mostly related to vblank handling,
and a minor fix to release a reference on the device tree nodes we're
parsing in the probe logic.

* tag 'sunxi-drm-fixes-for-4.7-2' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux:
  gpu: drm: sun4i_drv: add missing of_node_put after calling of_parse_phandle
  drm/sun4i: Send vblank event when the CRTC is disabled
  drm/sun4i: Report proper vblank

When proc_pid_attr_write() was changed to use memdup_user apparmor's
(interface violating) assumption that the setprocattr buffer was always
a single page was violated.

The size test is not strictly speaking needed as proc_pid_attr_write()
will reject anything larger, but for the sake of robustness we can keep
it in.

SMACK and SELinux look safe to me, but somebody else should probably
have a look just in case.

Based on original patch from Vegard Nossum <vegard.nossum@oracle.com>
modified for the case that apparmor provides null termination.

Fixes: bb646cdbReported-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: stable@kernel.org
Signed-off-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

This reverts commit 2f36db71.

It fixed a local root exploit but also introduced a dependency on
the lower file system implementing an mmap operation just to open a file,
which is a bit of a heavy hammer.  The right fix is to have mmap depend
on the existence of the mmap handler instead.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>

Pull block IO fixes from Jens Axboe:
 "Three small fixes that have been queued up and tested for this series:

   - A bug fix for xen-blkfront from Bob Liu, fixing an issue with
     incomplete requests during migration.

   - A fix for an ancient issue in retrieving the IO priority of a
     different PID than self, preventing that task from going away while
     we access it.  From Omar.

   - A writeback fix from Tahsin, fixing a case where we'd call ihold()
     with a zero ref count inode"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix use-after-free in sys_ioprio_get()
  writeback: inode cgroup wb switch should not call ihold()
  xen-blkfront: save uncompleted reqs in blkfront_resume()