Pull x86 fixes from Thomas Gleixner:
 "A set of x86 specific fixes and updates:

   - The CR2 corruption fixes which store CR2 early in the entry code
     and hand the stored address to the fault handlers.

   - Revert a forgotten leftover of the dropped FSGSBASE series.

   - Plug a memory leak in the boot code.

   - Make the Hyper-V assist functionality robust by zeroing the shadow
     page.

   - Remove a useless check for dead processes with LDT

   - Update paravirt and VMware maintainers entries.

   - A few cleanup patches addressing various compiler warnings"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/entry/64: Prevent clobbering of saved CR2 value
  x86/hyper-v: Zero out the VP ASSIST PAGE on allocation
  x86, boot: Remove multiple copy of static function sanitize_boot_params()
  x86/boot/compressed/64: Remove unused variable
  x86/boot/efi: Remove unused variables
  x86/mm, tracing: Fix CR2 corruption
  x86/entry/64: Update comments and sanity tests for create_gap
  x86/entry/64: Simplify idtentry a little
  x86/entry/32: Simplify common_exception
  x86/paravirt: Make read_cr2() CALLEE_SAVE
  MAINTAINERS: Update PARAVIRT_OPS_INTERFACE and VMWARE_HYPERVISOR_INTERFACE
  x86/process: Delete useless check for dead process with LDT
  x86: math-emu: Hide clang warnings for 16-bit overflow
  x86/e820: Use proper booleans instead of 0/1
  x86/apic: Silence -Wtype-limits compiler warnings
  x86/mm: Free sme_early_buffer after init
  x86/boot: Fix memory leak in default_get_smp_config()
  Revert "x86/ptrace: Prevent ptrace from clearing the FS/GS selector" and fix the test

Pull perf tooling updates from Thomas Gleixner:
 "A set of perf improvements and fixes:

  perf db-export:
   - Improvements in how COMM details are exported to databases for post
     processing and use in the sql-viewer.py UI.

   - Export switch events to the database.

  BPF:
   - Bump rlimit(MEMLOCK) for 'perf test bpf' and 'perf trace', just
     like selftests/bpf/bpf_rlimit.h do, which makes errors due to
     exhaustion of this limit, which are kinda cryptic (EPERM sometimes)
     less frequent.

  perf version:
   - Fix segfault due to missing OPT_END(), noticed on PowerPC.

  perf vendor events:
   - Add JSON files for IBM s/390 machine type 8561.

  perf cs-etm (ARM):
   - Fix two cases of error returns not bing done properly: Invalid
     ERR_PTR() use and loss of propagation error codes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits)
  perf version: Fix segfault due to missing OPT_END()
  perf vendor events s390: Add JSON files for machine type 8561
  perf cs-etm: Return errcode in cs_etm__process_auxtrace_info()
  perf cs-etm: Remove errnoeous ERR_PTR() usage in cs_etm__process_auxtrace_info
  perf scripts python: export-to-postgresql.py: Export switch events
  perf scripts python: export-to-sqlite.py: Export switch events
  perf db-export: Export switch events
  perf db-export: Factor out db_export__threads()
  perf script: Add scripting operation process_switch()
  perf scripts python: exported-sql-viewer.py: Use new 'has_calls' column
  perf scripts python: exported-sql-viewer.py: Remove redundant semi-colons
  perf scripts python: export-to-postgresql.py: Add has_calls column to comms table
  perf scripts python: export-to-sqlite.py: Add has_calls column to comms table
  perf db-export: Also export thread's current comm
  perf db-export: Factor out db_export__comm()
  perf scripts python: export-to-postgresql.py: Export comm details
  perf scripts python: export-to-sqlite.py: Export comm details
  perf db-export: Export comm details
  perf db-export: Fix a white space issue in db_export__sample()
  perf db-export: Move export__comm_thread into db_export__sample()
  ...

Pull core fixes from Thomas Gleixner:

 - A collection of objtool fixes which address recent fallout partially
   exposed by newer toolchains, clang, BPF and general code changes.

 - Force USER_DS for user stack traces

[ Note: the "objtool fixes" are not all to objtool itself, but for
  kernel code that triggers objtool warnings.

  Things like missing function size annotations, or code that confuses
  the unwinder etc.   - Linus]

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  objtool: Support conditional retpolines
  objtool: Convert insn type to enum
  objtool: Fix seg fault on bad switch table entry
  objtool: Support repeated uses of the same C jump table
  objtool: Refactor jump table code
  objtool: Refactor sibling call detection logic
  objtool: Do frame pointer check before dead end check
  objtool: Change dead_end_function() to return boolean
  objtool: Warn on zero-length functions
  objtool: Refactor function alias logic
  objtool: Track original function across branches
  objtool: Add mcsafe_handle_tail() to the uaccess safe list
  bpf: Disable GCC -fgcse optimization for ___bpf_prog_run()
  x86/uaccess: Remove redundant CLACs in getuser/putuser error paths
  x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail()
  x86/uaccess: Remove ELF function annotation from copy_user_handle_tail()
  x86/head/64: Annotate start_cpu0() as non-callable
  x86/entry: Fix thunk function ELF sizes
  x86/kvm: Don't call kvm_spurious_fault() from .fixup
  x86/kvm: Replace vmx_vmenter()'s call to kvm_spurious_fault() with UD2
  ...

Pull smp fix from Thomas Gleixner:
 "Add warnings to the smp function calls so callers from wrong contexts
  get detected"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smp: Warn on function calls from softirq context

Pull CONFIG_PREEMPT_RT stub config from Thomas Gleixner:
 "The real-time preemption patch set exists for almost 15 years now and
  while the vast majority of infrastructure and enhancements have found
  their way into the mainline kernel, the final integration of RT is
  still missing.

  Over the course of the last few years, we have worked on reducing the
  intrusivenness of the RT patches by refactoring kernel infrastructure
  to be more real-time friendly. Almost all of these changes were
  benefitial to the mainline kernel on their own, so there was no
  objection to integrate them.

  Though except for the still ongoing printk refactoring, the remaining
  changes which are required to make RT a first class mainline citizen
  are not longer arguable as immediately beneficial for the mainline
  kernel. Most of them are either reordering code flows or adding RT
  specific functionality.

  But this now has hit a wall and turned into a classic hen and egg
  problem:

     Maintainers are rightfully wary vs. these changes as they make only
     sense if the final integration of RT into the mainline kernel takes
     place.

  Adding CONFIG_PREEMPT_RT aims to solve this as a clear sign that RT
  will be fully integrated into the mainline kernel. The final
  integration of the missing bits and pieces will be of course done with
  the same careful approach as we have used in the past.

  While I'm aware that you are not entirely enthusiastic about that, I
  think that RT should receive the same treatment as any other widely
  used out of tree functionality, which we have accepted into mainline
  over the years.

  RT has become the de-facto standard real-time enhancement and is
  shipped by enterprise, embedded and community distros. It's in use
  throughout a wide range of industries: telecommunications, industrial
  automation, professional audio, medical devices, data acquisition,
  automotive - just to name a few major use cases.

  RT development is backed by a Linuxfoundation project which is
  supported by major stakeholders of this technology. The funding will
  continue over the actual inclusion into mainline to make sure that the
  functionality is neither introducing regressions, regressing itself,
  nor becomes subject to bitrot. There is also a lifely user community
  around RT as well, so contrary to the grim situation 5 years ago, it's
  a healthy project.

  As RT is still a good vehicle to exercise rarely used code paths and
  to detect hard to trigger issues, you could at least view it as a QA
  tool if nothing else"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/rt, Kconfig: Introduce CONFIG_PREEMPT_RT

Pull more KVM updates from Paolo Bonzini:
 "Mostly bugfixes, but also:

   - s390 support for KVM selftests

   - LAPIC timer offloading to housekeeping CPUs

   - Extend an s390 optimization for overcommitted hosts to all
     architectures

   - Debugging cleanups and improvements"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (25 commits)
  KVM: x86: Add fixed counters to PMU filter
  KVM: nVMX: do not use dangling shadow VMCS after guest reset
  KVM: VMX: dump VMCS on failed entry
  KVM: x86/vPMU: refine kvm_pmu err msg when event creation failed
  KVM: s390: Use kvm_vcpu_wake_up in kvm_s390_vcpu_wakeup
  KVM: Boost vCPUs that are delivering interrupts
  KVM: selftests: Remove superfluous define from vmx.c
  KVM: SVM: Fix detection of AMD Errata 1096
  KVM: LAPIC: Inject timer interrupt via posted interrupt
  KVM: LAPIC: Make lapic timer unpinned
  KVM: x86/vPMU: reset pmc->counter to 0 for pmu fixed_counters
  KVM: nVMX: Ignore segment base for VMX memory operand when segment not FS or GS
  kvm: x86: ioapic and apic debug macros cleanup
  kvm: x86: some tsc debug cleanup
  kvm: vmx: fix coccinelle warnings
  x86: kvm: avoid constant-conversion warning
  x86: kvm: avoid -Wsometimes-uninitized warning
  KVM: x86: expose AVX512_BF16 feature to guest
  KVM: selftests: enable pgste option for the linker on s390
  KVM: selftests: Move kvm_create_max_vcpus test to generic code
  ...

Pull SCSI fixes from James Bottomley:
 "This is the final round of mostly small fixes in our initial submit.

  It's mostly minor fixes and driver updates. The only change of note is
  adding a virt_boundary_mask to the SCSI host and host template to
  parametrise this for NVMe devices instead of having them do a call in
  slave_alloc. It's a fairly straightforward conversion except in the
  two NVMe handling drivers that didn't set it who now have a virtual
  infinity parameter added"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (24 commits)
  scsi: megaraid_sas: set an unlimited max_segment_size
  scsi: mpt3sas: set an unlimited max_segment_size for SAS 3.0 HBAs
  scsi: IB/srp: set virt_boundary_mask in the scsi host
  scsi: IB/iser: set virt_boundary_mask in the scsi host
  scsi: storvsc: set virt_boundary_mask in the scsi host template
  scsi: ufshcd: set max_segment_size in the scsi host template
  scsi: core: take the DMA max mapping size into account
  scsi: core: add a host / host template field for the virt boundary
  scsi: core: Fix race on creating sense cache
  scsi: sd_zbc: Fix compilation warning
  scsi: libfc: fix null pointer dereference on a null lport
  scsi: zfcp: fix GCC compiler warning emitted with -Wmaybe-uninitialized
  scsi: zfcp: fix request object use-after-free in send path causing wrong traces
  scsi: zfcp: fix request object use-after-free in send path causing seqno errors
  scsi: megaraid_sas: Update driver version to 07.710.50.00
  scsi: megaraid_sas: Add module parameter for FW Async event logging
  scsi: megaraid_sas: Enable msix_load_balance for Invader and later controllers
  scsi: megaraid_sas: Fix calculation of target ID
  scsi: lpfc: reduce stack size with CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE
  scsi: devinfo: BLIST_TRY_VPD_PAGES for SanDisk Cruzer Blade
  ...

Pull more Kbuild updates from Masahiro Yamada:

 - match the directory structure of the linux-libc-dev package to that
   of Debian-based distributions

 - fix incorrect include/config/auto.conf generation when Kconfig
   creates it along with the .config file

 - remove misleading $(AS) from documents

 - clean up precious tag files by distclean instead of mrproper

 - add a new coccinelle patch for devm_platform_ioremap_resource
   migration

 - refactor module-related scripts to read modules.order instead of
   $(MODVERDIR)/*.mod files to get the list of created modules

 - remove MODVERDIR

 - update list of header compile-test

 - add -fcf-protection=none flag to avoid conflict with the retpoline
   flags when CONFIG_RETPOLINE=y

 - misc cleanups

* tag 'kbuild-v5.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (25 commits)
  kbuild: add -fcf-protection=none when using retpoline flags
  kbuild: update compile-test header list for v5.3-rc1
  kbuild: split out *.mod out of {single,multi}-used-m rules
  kbuild: remove 'prepare1' target
  kbuild: remove the first line of *.mod files
  kbuild: create *.mod with full directory path and remove MODVERDIR
  kbuild: export_report: read modules.order instead of .tmp_versions/*.mod
  kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod
  kbuild: modsign: read modules.order instead of $(MODVERDIR)/*.mod
  kbuild: modinst: read modules.order instead of $(MODVERDIR)/*.mod
  scsi: remove pointless $(MODVERDIR)/$(obj)/53c700.ver
  kbuild: remove duplication from modules.order in sub-directories
  kbuild: get rid of kernel/ prefix from in-tree modules.{order,builtin}
  kbuild: do not create empty modules.order in the prepare stage
  coccinelle: api: add devm_platform_ioremap_resource script
  kbuild: compile-test headers listed in header-test-m as well
  kbuild: remove unused hostcc-option
  kbuild: remove tag files by distclean instead of mrproper
  kbuild: add --hash-style= and --build-id unconditionally
  kbuild: get rid of misleading $(AS) from documents
  ...

Pull dcache and mountpoint updates from Al Viro:
 "Saner handling of refcounts to mountpoints.

  Transfer the counting reference from struct mount ->mnt_mountpoint
  over to struct mountpoint ->m_dentry. That allows us to get rid of the
  convoluted games with ordering of mount shutdowns.

  The cost is in teaching shrink_dcache_{parent,for_umount} to cope with
  mixed-filesystem shrink lists, which we'll also need for the Slab
  Movable Objects patchset"

* 'work.dcache2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  switch the remnants of releasing the mountpoint away from fs_pin
  get rid of detach_mnt()
  make struct mountpoint bear the dentry reference to mountpoint, not struct mount
  Teach shrink_dcache_parent() to cope with mixed-filesystem shrink lists
  fs/namespace.c: shift put_mountpoint() to callers of unhash_mnt()
  __detach_mounts(): lookup_mountpoint() can't return ERR_PTR() anymore
  nfs: dget_parent() never returns NULL
  ceph: don't open-code the check for dead lockref

The recent fix for CR2 corruption introduced a new way to reliably corrupt
the saved CR2 value.

CR2 is saved early in the entry code in RDX, which is the third argument to
the fault handling functions. But it missed that between saving and
invoking the fault handler enter_from_user_mode() can be called. RDX is a
caller saved register so the invoked function can freely clobber it with
the obvious consequences.

The TRACE_IRQS_OFF call is safe as it calls through the thunk which
preserves RDX, but TRACE_IRQS_OFF_DEBUG is not because it also calls into
C-code outside of the thunk.

Store CR2 in R12 instead which is a callee saved register and move R12 to
RDX just before calling the fault handler.

Fixes: a0d14b89 ("x86/mm, tracing: Fix CR2 corruption")
Reported-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1907201020540.1782@nanos.tec.linutronix.de

It's clearly documented that smp function calls cannot be invoked from
softirq handling context. Unfortunately nothing enforces that or emits a
warning.

A single function call can be invoked from softirq context only via
smp_call_function_single_async().

The only legit context is task context, so add a warning to that effect.
Reported-by: luferry <luferry@163.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190718160601.GP3402@hirez.programming.kicks-ass.net

Updates KVM_CAP_PMU_EVENT_FILTER so it can also whitelist or blacklist
fixed counters.
Signed-off-by: Eric Hankland <ehankland@google.com>
[No need to check padding fields for zero. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

If a KVM guest is reset while running a nested guest, free_nested will
disable the shadow VMCS execution control in the vmcs01.  However,
on the next KVM_RUN vmx_vcpu_run would nevertheless try to sync
the VMCS12 to the shadow VMCS which has since been freed.

This causes a vmptrld of a NULL pointer on my machime, but Jan reports
the host to hang altogether.  Let's see how much this trivial patch fixes.
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

This is useful for debugging, and is ratelimited nowadays.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

If a perf_event creation fails due to any reason of the host perf
subsystem, it has no chance to log the corresponding event for guest
which may cause abnormal sampling data in guest result. In debug mode,
this message helps to understand the state of vPMC and we may not
limit the number of occurrences but not in a spamming style.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Use kvm_vcpu_wake_up() in kvm_s390_vcpu_wakeup().
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Inspired by commit 9cac38dd (KVM/s390: Set preempted flag during
vcpu wakeup and interrupt delivery), we want to also boost not just
lock holders but also vCPUs that are delivering interrupts. Most
smp_call_function_many calls are synchronous, so the IPI target vCPUs
are also good yield candidates.  This patch introduces vcpu->ready to
boost vCPUs during wakeup and interrupt delivery time; unlike s390 we do
not reuse vcpu->preempted so that voluntarily preempted vCPUs are taken
into account by kvm_vcpu_on_spin, but vmx_vcpu_pi_put is not affected
(VT-d PI handles voluntary preemption separately, in pi_pre_block).

Testing on 80 HT 2 socket Xeon Skylake server, with 80 vCPUs VM 80GB RAM:
ebizzy -M

            vanilla     boosting    improved
1VM          21443       23520         9%
2VM           2800        8000       180%
3VM           1800        3100        72%

Testing on my Haswell desktop 8 HT, with 8 vCPUs VM 8GB RAM, two VMs,
one running ebizzy -M, the other running 'stress --cpu 2':

w/ boosting + w/o pv sched yield(vanilla)

            vanilla     boosting   improved
              1570         4000      155%

w/ boosting + w/ pv sched yield(vanilla)

            vanilla     boosting   improved
              1844         5157      179%

w/o boosting, perf top in VM:

 72.33%  [kernel]       [k] smp_call_function_many
  4.22%  [kernel]       [k] call_function_i
  3.71%  [kernel]       [k] async_page_fault

w/ boosting, perf top in VM:

 38.43%  [kernel]       [k] smp_call_function_many
  6.31%  [kernel]       [k] async_page_fault
  6.13%  libc-2.23.so   [.] __memcpy_avx_unaligned
  4.88%  [kernel]       [k] call_function_interrupt

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The code in vmx.c does not use "program_invocation_name", so there
is no need to "#define _GNU_SOURCE" here.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When CPU raise #NPF on guest data access and guest CR4.SMAP=1, it is
possible that CPU microcode implementing DecodeAssist will fail
to read bytes of instruction which caused #NPF. This is AMD errata
1096 and it happens because CPU microcode reading instruction bytes
incorrectly attempts to read code as implicit supervisor-mode data
accesses (that is, just like it would read e.g. a TSS), which are
susceptible to SMAP faults. The microcode reads CS:RIP and if it is
a user-mode address according to the page tables, the processor
gives up and returns no instruction bytes.  In this case,
GuestIntrBytes field of the VMCB on a VMEXIT will incorrectly
return 0 instead of the correct guest instruction bytes.

Current KVM code attemps to detect and workaround this errata, but it
has multiple issues:

1) It mistakenly checks if guest CR4.SMAP=0 instead of guest CR4.SMAP=1,
which is required for encountering a SMAP fault.

2) It assumes SMAP faults can only occur when guest CPL==3.
However, in case guest CR4.SMEP=0, the guest can execute an instruction
which reside in a user-accessible page with CPL<3 priviledge. If this
instruction raise a #NPF on it's data access, then CPU DecodeAssist
microcode will still encounter a SMAP violation.  Even though no sane
OS will do so (as it's an obvious priviledge escalation vulnerability),
we still need to handle this semanticly correct in KVM side.

Note that (2) *is* a useful optimization, because CR4.SMAP=1 is an easy
triggerable condition and guests usually enable SMAP together with SMEP.
If the vCPU has CR4.SMEP=1, the errata could indeed be encountered onlt
at guest CPL==3; otherwise, the CPU would raise a SMEP fault to guest
instead of #NPF.  We keep this condition to avoid false positives in
the detection of the errata.

In addition, to avoid future confusion and improve code readbility,
include details of the errata in code and not just in commit message.

Fixes: 05d5a486 ("KVM: SVM: Workaround errata#1096 (insn_len maybe zero on SMAP violation)")
Cc: Singh Brijesh <brijesh.singh@amd.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Dedicated instances are currently disturbed by unnecessary jitter due
to the emulated lapic timers firing on the same pCPUs where the
vCPUs reside.  There is no hardware virtual timer on Intel for guest
like ARM, so both programming timer in guest and the emulated timer fires
incur vmexits.  This patch tries to avoid vmexit when the emulated timer
fires, at least in dedicated instance scenario when nohz_full is enabled.

In that case, the emulated timers can be offload to the nearest busy
housekeeping cpus since APICv has been found for several years in server
processors. The guest timer interrupt can then be injected via posted interrupts,
which are delivered by the housekeeping cpu once the emulated timer fires.

The host should tuned so that vCPUs are placed on isolated physical
processors, and with several pCPUs surplus for busy housekeeping.
If disabled mwait/hlt/pause vmexits keep the vCPUs in non-root mode,
~3% redis performance benefit can be observed on Skylake server, and the
number of external interrupt vmexits drops substantially.  Without patch

            VM-EXIT  Samples  Samples%  Time%   Min Time  Max Time   Avg time
EXTERNAL_INTERRUPT    42916    49.43%   39.30%   0.47us   106.09us   0.71us ( +-   1.09% )

While with patch:

            VM-EXIT  Samples  Samples%  Time%   Min Time  Max Time         Avg time
EXTERNAL_INTERRUPT    6871     9.29%     2.96%   0.44us    57.88us   0.72us ( +-   4.02% )

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The gcc -fcf-protection=branch option is not compatible with
-mindirect-branch=thunk-extern. The latter is used when
CONFIG_RETPOLINE is selected, and this will fail to build with
a gcc which has -fcf-protection=branch enabled by default. Adding
-fcf-protection=none when building with retpoline enabled
prevents such build failures.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

 - Some headers graduated from the blacklist

 - hyperv_timer.h joined the header-test when CONFIG_X86=y

 - nf_tables*.h joined the header-test when CONFIG_NF_TABLES is
   enabled.

 - The entry for nf_tables_offload.h was added to fix build error for
   the combination of CONFIG_NF_TABLES=n and CONFIG_KERNEL_HEADER_TEST=y.

 - The entry for iomap.h was added because this header is supposed to
   be included only when CONFIG_BLOCK=y
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Pull ARM SoC defconfig updates from Olof Johansson:
 "We keep this in a separate branch to avoid cross-branch conflicts, but
  most of the material here is fairly boring -- some new drivers turned
  on for hardware since they were merged, and some refreshed files due
  to time having moved a lot of entries around"

* tag 'armsoc-defconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (47 commits)
  ARM: configs: multi_v5: Remove duplicate ASPEED options
  arm64: defconfig: Enable CONFIG_KEYBOARD_SNVS_PWRKEY as module
  ARM: imx_v6_v7_defconfig: Enable CONFIG_ARM_IMX_CPUFREQ_DT
  defconfig: arm64: enable i.MX8 SCU octop driver
  arm64: defconfig: Add i.MX SCU SoC info driver
  arm64: defconfig: Enable CONFIG_QORIQ_THERMAL
  ARM: imx_v6_v7_defconfig: Select CONFIG_NVMEM_SNVS_LPGPR
  arm64: defconfig: ARM_IMX_CPUFREQ_DT=m
  ARM: imx_v6_v7_defconfig: Add TPM PWM support by default
  ARM: imx_v6_v7_defconfig: Enable the OV2680 camera driver
  ARM: imx_v6_v7_defconfig: Enable CONFIG_THERMAL_STATISTICS
  arm64: defconfig: NVMEM_IMX_OCOTP=y for imx8m
  ARM: multi_v7_defconfig: enable STMFX pinctrl support
  arm64 defconfig: enable LVM support
  ARM: configs: multi_v5: Add more ASPEED devices
  arm64: defconfig: Add Tegra194 PCIe driver
  ARM: configs: aspeed: Add new drivers
  ARM: exynos_defconfig: Enable Panfrost and Lima drivers
  ARM: multi_v7_defconfig: Enable Panfrost and Lima drivers
  arm64 defconfig: enable Mellanox cards
  ...

Pull ARM Devicetree updates from Olof Johansson:
 "We continue to see a lot of new material. I've highlighted some of it
  below, but there's been more beyond that as well.

  One of the sweeping changes is that many boards have seen their ARM
  Mali GPU devices added to device trees, since the DRM drivers have now
  been merged.

  So, with the caveat that I have surely missed several great
  contributions, here's a collection of the material this time around:

  New SoCs:

   - Mediatek mt8183 (4x Cortex-A73 + 4x Cortex-A53)

   - TI J721E (2x Cortex-A72 + 3x Cortex-R5F + 3 DSPs + MMA)

   - Amlogic G12B (4x Cortex-A73 + 2x Cortex-A53)

  New Boards / platforms:

   - Aspeed BMC support for a number of new server platforms

   - Kontron SMARC SoM (several i.MX6 versions)

   - Novtech's Meerkat96 (i.MX7)

   - ST Micro Avenger96 board

   - Hardkernel ODROID-N2 (Amlogic G12B)

   - Purism Librem5 devkit (i.MX8MQ)

   - Google Cheza (Qualcomm SDM845)

   - Qualcomm Dragonboard 845c (Qualcomm SDM845)

   - Hugsun X99 TV Box (Rockchip RK3399)

   - Khadas Edge/Edge-V/Captain (Rockchip RK3399)

  Updated / expanded boards and platforms:

   - Renesas r7s9210 has a lot of new peripherals added

   - Fixes and polish for Rockchip-based Chromebooks

   - Amlogic G12A has a lot of peripherals added

   - Nvidia Jetson Nano sees various fixes and improvements, and is now
     at feature parity with TX1"

* tag 'armsoc-dt' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (586 commits)
  ARM: dts: gemini: Set DIR-685 SPI CS as active low
  ARM: dts: exynos: Adjust buck[78] regulators to supported values on Arndale Octa
  ARM: dts: exynos: Adjust buck[78] regulators to supported values on Odroid XU3 family
  ARM: dts: exynos: Move Mali400 GPU node to "/soc"
  ARM: dts: exynos: Fix imprecise abort on Mali GPU probe on Exynos4210
  arm64: dts: qcom: qcs404: Add missing space for cooling-cells property
  arm64: dts: rockchip: Fix USB3 Type-C on rk3399-sapphire
  arm64: dts: rockchip: Update DWC3 modules on RK3399 SoCs
  arm64: dts: rockchip: enable rk3328 watchdog clock
  ARM: dts: rockchip: add display nodes for rk322x
  ARM: dts: rockchip: fix vop iommu-cells on rk322x
  arm64: dts: rockchip: Add support for Hugsun X99 TV Box
  arm64: dts: rockchip: Define values for the IPA governor for rock960
  arm64: dts: rockchip: Fix multiple thermal zones conflict in rk3399.dtsi
  arm64: dts: rockchip: add core dtsi file for RK3399Pro SoCs
  arm64: dts: rockchip: improve rk3328-roc-cc rgmii performance.
  Revert "ARM: dts: rockchip: set PWM delay backlight settings for Minnie"
  ARM: dts: rockchip: Configure BT_DEV_WAKE in on rk3288-veyron
  arm64: dts: qcom: sdm845-cheza: add initial cheza dt
  ARM: dts: msm8974-FP2: Add vibration motor
  ...

Pull ARM SoC-related driver updates from Olof Johansson:
 "Various driver updates for platforms and a couple of the small driver
  subsystems we merge through our tree:

   - A driver for SCU (system control) on NXP i.MX8QXP

   - Qualcomm Always-on Subsystem messaging driver (AOSS QMP)

   - Qualcomm PM support for MSM8998

   - Support for a newer version of DRAM PHY driver for Broadcom (DPFE)

   - Reset controller support for Bitmain BM1880

   - TI SCI (System Control Interface) support for CPU control on AM654
     processors

   - More TI sysc refactoring and rework"

* tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (84 commits)
  reset: remove redundant null check on pointer dev
  soc: rockchip: work around clang warning
  dt-bindings: reset: imx7: Fix the spelling of 'indices'
  soc: imx: Add i.MX8MN SoC driver support
  soc: aspeed: lpc-ctrl: Fix probe error handling
  soc: qcom: geni: Add support for ACPI
  firmware: ti_sci: Fix gcc unused-but-set-variable warning
  firmware: ti_sci: Use the correct style for SPDX License Identifier
  soc: imx8: Use existing of_root directly
  soc: imx8: Fix potential kernel dump in error path
  firmware/psci: psci_checker: Park kthreads before stopping them
  memory: move jedec_ddr.h from include/memory to drivers/memory/
  memory: move jedec_ddr_data.c from lib/ to drivers/memory/
  MAINTAINERS: Remove myself as qcom maintainer
  soc: aspeed: lpc-ctrl: make parameter optional
  soc: qcom: apr: Don't use reg for domain id
  soc: qcom: fix QCOM_AOSS_QMP dependency and build errors
  memory: tegra: Fix -Wunused-const-variable
  firmware: tegra: Early resume BPMP
  soc/tegra: Select pinctrl for Tegra194
  ...

Pull ARM SoC platform updates from Olof Johansson:
 "SoC platform changes. Main theme this merge window:

   - The Netx platform (Netx 100/500) platform is removed by Linus
     Walleij-- the SoC doesn't have active maintainers with hardware,
     and in discussions with the vendor the agreement was that it's OK
     to remove.

   - Russell King has a series of patches that cleans up and refactors
     SA1101 and RiscPC support"

* tag 'armsoc-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (47 commits)
  ARM: stm32: use "depends on" instead of "if" after prompt
  ARM: sa1100: convert to common clock framework
  ARM: exynos: Cleanup cppcheck shifting warning
  ARM: pxa/lubbock: remove lubbock_set_misc_wr() from global view
  ARM: exynos: Only build MCPM support if used
  arm: add missing include platform-data/atmel.h
  ARM: davinci: Use GPIO lookup table for DA850 LEDs
  ARM: OMAP2: drop explicit assembler architecture
  ARM: use arch_extension directive instead of arch argument
  ARM: imx: Switch imx7d to imx-cpufreq-dt for speed-grading
  ARM: bcm: Enable PINCTRL for ARCH_BRCMSTB
  ARM: bcm: Enable ARCH_HAS_RESET_CONTROLLER for ARCH_BRCMSTB
  ARM: riscpc: enable chained scatterlist support
  ARM: riscpc: reduce IRQ handling code
  ARM: riscpc: move RiscPC assembly files from arch/arm/lib to mach-rpc
  ARM: riscpc: parse video information from tagged list
  ARM: riscpc: add ecard quirk for Atomwide 3port serial card
  MAINTAINERS: mvebu: Add git entry
  soc: ti: pm33xx: Add a print while entering RTC only mode with DDR in self-refresh
  ARM: OMAP2+: Make some variables static
  ...

Pull drm fixes from Daniel Vetter:
 "Dave is back in shape, but now family got it so I'm doing the pull.
  Two things worthy of note:

   - nouveau feature pull was way too late, Dave&me decided to not take
     that, so Ben spun up a pull with just the fixes.

   - after some chatting with the arm display maintainers we decided to
     change a bit how that's maintained, for more oversight/review and
     cross vendor collab.

  More details below:

  nouveau:
   - bugfixes
   - TU116 enabling (minor iteration) :w

  amdgpu:
   - large pile of fixes for new hw support this release (navi, vega20)
   - audio hotplug fix
   - bunch of corner cases and small fixes all over for amdgpu/kfd

  komeda:
   - back out some new properties (from this merge window) that needs
     more pondering.

  bochs:
   - fb pitch setup

  core:
   - a new panel quirk
   - misc fixes"

* tag 'drm-next-2019-07-19' of git://anongit.freedesktop.org/drm/drm: (73 commits)
  drm/nouveau/secboot/gp102-: remove WAR for SEC2 RTOS start bug
  drm/nouveau/flcn/gp102-: improve implementation of bind_context() on SEC2/GSP
  drm/nouveau: fix memory leak in nouveau_conn_reset()
  drm/nouveau/dmem: missing mutex_lock in error path
  drm/nouveau/hwmon: return EINVAL if the GPU is powered down for sensors reads
  drm/nouveau: fix bogus GPL-2 license header
  drm/nouveau: fix bogus GPL-2 license header
  drm/nouveau/i2c: Enable i2c pads & busses during preinit
  drm/nouveau/disp/tu102-: wire up scdc parameter setter
  drm/nouveau/core: recognise TU116 chipset
  drm/nouveau/kms: disallow dual-link harder if hdmi connection detected
  drm/nouveau/disp/nv50-: fix center/aspect-corrected scaling
  drm/nouveau/disp/nv50-: force scaler for any non-default LVDS/eDP modes
  drm/nouveau/mcp89/mmu: Use mcp77_mmu_new instead of g84_mmu_new on MCP89.
  drm/amd/display: init res_pool dccg_ref, dchub_ref with xtalin_freq
  drm/amdgpu/pm: remove check for pp funcs in freq sysfs handlers
  drm/amd/display: Force uclk to max for every state
  drm/amdkfd: Remove GWS from process during uninit
  drm/amd/amdgpu: Fix offset for vmid selection in debugfs interface
  drm/amd/powerplay: update vega20 driver if to fit latest SMU firmware
  ...

Pull crypto fixes from Herbert Xu:

 - Fix missed wake-up race in padata

 - Use crypto_memneq in ccp

 - Fix version check in ccp

 - Fix fuzz test failure in ccp

 - Fix potential double free in crypto4xx

 - Fix compile warning in stm32

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  padata: use smp_mb in padata_reorder to avoid orphaned padata jobs
  crypto: ccp - Fix SEV_VERSION_GREATER_OR_EQUAL
  crypto: ccp/gcm - use const time tag comparison.
  crypto: ccp - memset structure fields to zero before reuse
  crypto: crypto4xx - fix a potential double free in ppc4xx_trng_probe
  crypto: stm32/hash - Fix incorrect printk modifier for size_t

This fell into disrepair a while ago, and the majority of hits to the
snapshots were from bots, so it's more trouble to keep running than it's worth.
Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull tracing fix from Steven Rostedt:
 "Eiichi Tsukata found a small bug from the fixup of the stack code

  Removing ULONG_MAX as the marker for the user stack trace end, made
  the tracing code not know where the end is. The end is now marked with
  a zero (NULL) pointer. Eiichi fixed this in the tracing code"

* tag 'trace-v5.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix user stack trace "??" output

Pull arch/csky pupdates from Guo Ren:
 "This round of csky subsystem gives two features (ASID algorithm
  update, Perf pmu record support) and some fixups.

  ASID updates:
   - Revert mmu ASID mechanism
   - Add new asid lib code from arm
   - Use generic asid algorithm to implement switch_mm
   - Improve tlb operation with help of asid

  Perf pmu record support:
   - Init pmu as a device
   - Add count-width property for csky pmu
   - Add pmu interrupt support
   - Fix perf record in kernel/user space
   - dt-bindings: Add csky PMU bindings

  Fixes:
   - Fixup no panic in kernel for some traps
   - Fixup some error count in 810 & 860.
   - Fixup abiv1 memset error"

* tag 'csky-for-linus-5.3-rc1' of git://github.com/c-sky/csky-linux:
  csky: Fixup abiv1 memset error
  csky: Improve tlb operation with help of asid
  csky: Use generic asid algorithm to implement switch_mm
  csky: Add new asid lib code from arm
  csky: Revert mmu ASID mechanism
  dt-bindings: csky: Add csky PMU bindings
  dt-bindings: interrupt-controller: Update csky mpintc
  csky: Fixup some error count in 810 & 860.
  csky: Fix perf record in kernel/user space
  csky: Add pmu interrupt support
  csky: Add count-width property for csky pmu
  csky: Init pmu as a device
  csky: Fixup no panic in kernel for some traps
  csky: Select intc & timer drivers

Pull xen updates from Juergen Gross:
 "Fixes and features:

   - A series to introduce a common command line parameter for disabling
     paravirtual extensions when running as a guest in virtualized
     environment

   - A fix for int3 handling in Xen pv guests

   - Removal of the Xen-specific tmem driver as support of tmem in Xen
     has been dropped (and it was experimental only)

   - A security fix for running as Xen dom0 (XSA-300)

   - A fix for IRQ handling when offlining cpus in Xen guests

   - Some small cleanups"

* tag 'for-linus-5.3a-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: let alloc_xenballooned_pages() fail if not enough memory free
  xen/pv: Fix a boot up hang revealed by int3 self test
  x86/xen: Add "nopv" support for HVM guest
  x86/paravirt: Remove const mark from x86_hyper_xen_hvm variable
  xen: Map "xen_nopv" parameter to "nopv" and mark it obsolete
  x86: Add "nopv" parameter to disable PV extensions
  x86/xen: Mark xen_hvm_need_lapic() and xen_x2apic_para_available() as __init
  xen: remove tmem driver
  Revert "x86/paravirt: Set up the virt_spin_lock_key after static keys get initialized"
  xen/events: fix binding user event channels to cpus

Pull iomap split/cleanup from Darrick Wong:
 "As promised, here's the second part of the iomap merge for 5.3, in
  which we break up iomap.c into smaller files grouped by functional
  area so that it'll be easier in the long run to maintain cohesiveness
  of code units and to review incoming patches. There are no functional
  changes and fs/iomap.c split cleanly.

  Summary:

   - Regroup the fs/iomap.c code by major functional area so that we can
     start development for 5.4 from a more stable base"

* tag 'iomap-5.3-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: move internal declarations into fs/iomap/
  iomap: move the main iteration code into a separate file
  iomap: move the buffered IO code into a separate file
  iomap: move the direct IO code into a separate file
  iomap: move the SEEK_HOLE code into a separate file
  iomap: move the file mapping reporting code into a separate file
  iomap: move the swapfile code into a separate file
  iomap: start moving code to fs/iomap/

Pull misc vfs updates from Al Viro:
 "Assorted stuff"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  perf_event_get(): don't bother with fget_raw()
  vfs: update d_make_root() description

Pull adfs updates from Al Viro:
 "More ADFS patches from Russell King"

* 'work.adfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs/adfs: add time stamp and file type helpers
  fs/adfs: super: limit idlen according to directory type
  fs/adfs: super: fix use-after-free bug
  fs/adfs: super: safely update options on remount
  fs/adfs: super: correct superblock flags
  fs/adfs: clean up indirect disc addresses and fragment IDs
  fs/adfs: clean up error message printing
  fs/adfs: use %pV for error messages
  fs/adfs: use format_version from disc_record
  fs/adfs: add helper to get filesystem size
  fs/adfs: add helper to get discrecord from map
  fs/adfs: correct disc record structure

Pull vfs mount updates from Al Viro:
 "The first part of mount updates.

  Convert filesystems to use the new mount API"

* 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  mnt_init(): call shmem_init() unconditionally
  constify ksys_mount() string arguments
  don't bother with registering rootfs
  init_rootfs(): don't bother with init_ramfs_fs()
  vfs: Convert smackfs to use the new mount API
  vfs: Convert selinuxfs to use the new mount API
  vfs: Convert securityfs to use the new mount API
  vfs: Convert apparmorfs to use the new mount API
  vfs: Convert openpromfs to use the new mount API
  vfs: Convert xenfs to use the new mount API
  vfs: Convert gadgetfs to use the new mount API
  vfs: Convert oprofilefs to use the new mount API
  vfs: Convert ibmasmfs to use the new mount API
  vfs: Convert qib_fs/ipathfs to use the new mount API
  vfs: Convert efivarfs to use the new mount API
  vfs: Convert configfs to use the new mount API
  vfs: Convert binfmt_misc to use the new mount API
  convenience helper: get_tree_single()
  convenience helper get_tree_nodev()
  vfs: Kill sget_userns()
  ...

Pull networking fixes from David Miller:

 1) Fix AF_XDP cq entry leak, from Ilya Maximets.

 2) Fix handling of PHY power-down on RTL8411B, from Heiner Kallweit.

 3) Add some new PCI IDs to iwlwifi, from Ihab Zhaika.

 4) Fix handling of neigh timers wrt. entries added by userspace, from
    Lorenzo Bianconi.

 5) Various cases of missing of_node_put(), from Nishka Dasgupta.

 6) The new NET_ACT_CT needs to depend upon NF_NAT, from Yue Haibing.

 7) Various RDS layer fixes, from Gerd Rausch.

 8) Fix some more fallout from TCQ_F_CAN_BYPASS generalization, from
    Cong Wang.

 9) Fix FIB source validation checks over loopback, also from Cong Wang.

10) Use promisc for unsupported number of filters, from Justin Chen.

11) Missing sibling route unlink on failure in ipv6, from Ido Schimmel.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (90 commits)
  tcp: fix tcp_set_congestion_control() use from bpf hook
  ag71xx: fix return value check in ag71xx_probe()
  ag71xx: fix error return code in ag71xx_probe()
  usb: qmi_wwan: add D-Link DWM-222 A2 device ID
  bnxt_en: Fix VNIC accounting when enabling aRFS on 57500 chips.
  net: dsa: sja1105: Fix missing unlock on error in sk_buff()
  gve: replace kfree with kvfree
  selftests/bpf: fix test_xdp_noinline on s390
  selftests/bpf: fix "valid read map access into a read-only array 1" on s390
  net/mlx5: Replace kfree with kvfree
  MAINTAINERS: update netsec driver
  ipv6: Unlink sibling route in case of failure
  liquidio: Replace vmalloc + memset with vzalloc
  udp: Fix typo in net/ipv4/udp.c
  net: bcmgenet: use promisc for unsupported filters
  ipv6: rt6_check should return NULL if 'from' is NULL
  tipc: initialize 'validated' field of received packets
  selftests: add a test case for rp_filter
  fib: relax source validation check for loopback packets
  mlxsw: spectrum: Do not process learned records with a dummy FID
  ...

Merge yet more updates from Andrew Morton:
 "The rest of MM and a kernel-wide procfs cleanup.

  Summary of the more significant patches:

   - Patch series "mm/memory_hotplug: Factor out memory block
     devicehandling", v3. David Hildenbrand.

     Some spring-cleaning of the memory hotplug code, notably in
     drivers/base/memory.c

   - "mm: thp: fix false negative of shmem vma's THP eligibility". Yang
     Shi.

     Fix /proc/pid/smaps output for THP pages used in shmem.

   - "resource: fix locking in find_next_iomem_res()" + 1. Nadav Amit.

     Bugfix and speedup for kernel/resource.c

   - Patch series "mm: Further memory block device cleanups", David
     Hildenbrand.

     More spring-cleaning of the memory hotplug code.

   - Patch series "mm: Sub-section memory hotplug support". Dan
     Williams.

     Generalise the memory hotplug code so that pmem can use it more
     completely. Then remove the hacks from the libnvdimm code which
     were there to work around the memory-hotplug code's constraints.

   - "proc/sysctl: add shared variables for range check", Matteo Croce.

     We have about 250 instances of

          int zero;
          ...
                  .extra1 = &zero,

     in the tree. This is a tree-wide sweep to make all those private
     "zero"s and "one"s use global variables.

     Alas, it isn't practical to make those two global integers const"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (38 commits)
  proc/sysctl: add shared variables for range check
  mm: migrate: remove unused mode argument
  mm/sparsemem: cleanup 'section number' data types
  libnvdimm/pfn: stop padding pmem namespaces to section alignment
  libnvdimm/pfn: fix fsdax-mode namespace info-block zero-fields
  mm/devm_memremap_pages: enable sub-section remap
  mm: document ZONE_DEVICE memory-model implications
  mm/sparsemem: support sub-section hotplug
  mm/sparsemem: prepare for sub-section ranges
  mm: kill is_dev_zone() helper
  mm/hotplug: kill is_dev_zone() usage in __remove_pages()
  mm/sparsemem: convert kmalloc_section_memmap() to populate_section_memmap()
  mm/hotplug: prepare shrink_{zone, pgdat}_span for sub-section removal
  mm/sparsemem: add helpers track active portions of a section at boot
  mm/sparsemem: introduce a SECTION_IS_EARLY flag
  mm/sparsemem: introduce struct mem_section_usage
  drivers/base/memory.c: get rid of find_memory_block_hinted()
  mm/memory_hotplug: move and simplify walk_memory_blocks()
  mm/memory_hotplug: rename walk_memory_range() and pass start+size instead of pfns
  mm: make register_mem_sect_under_node() static
  ...

Commit c5c27a0a ("x86/stacktrace: Remove the pointless ULONG_MAX
marker") removes ULONG_MAX marker from user stack trace entries but
trace_user_stack_print() still uses the marker and it outputs unnecessary
"??".

For example:

            less-1911  [001] d..2    34.758944: <user stack trace>
   =>  <00007f16f2295910>
   => ??
   => ??
   => ??
   => ??
   => ??
   => ??
   => ??

The user stack trace code zeroes the storage before saving the stack, so if
the trace is shorter than the maximum number of entries it can terminate
the print loop if a zero entry is detected.

Link: http://lkml.kernel.org/r/20190630085438.25545-1-devel@etsukata.com

Cc: stable@vger.kernel.org
Fixes: 4285f2fc ("tracing: Remove the ULONG_MAX stack trace hackery")
Signed-off-by: Eiichi Tsukata <devel@etsukata.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The VP ASSIST PAGE is an "overlay" page (see Hyper-V TLFS's Section
5.2.1 "GPA Overlay Pages" for the details) and here is an excerpt:

"The hypervisor defines several special pages that "overlay" the guest's
 Guest Physical Addresses (GPA) space. Overlays are addressed GPA but are
 not included in the normal GPA map maintained internally by the hypervisor.
 Conceptually, they exist in a separate map that overlays the GPA map.

 If a page within the GPA space is overlaid, any SPA page mapped to the
 GPA page is effectively "obscured" and generally unreachable by the
 virtual processor through processor memory accesses.

 If an overlay page is disabled, the underlying GPA page is "uncovered",
 and an existing mapping becomes accessible to the guest."

SPA = System Physical Address = the final real physical address.

When a CPU (e.g. CPU1) is onlined, hv_cpu_init() allocates the VP ASSIST
PAGE and enables the EOI optimization for this CPU by writing the MSR
HV_X64_MSR_VP_ASSIST_PAGE. From now on, hvp->apic_assist belongs to the
special SPA page, and this CPU *always* uses hvp->apic_assist (which is
shared with the hypervisor) to decide if it needs to write the EOI MSR.

When a CPU is offlined then on the outgoing CPU:
1. hv_cpu_die() disables the EOI optimizaton for this CPU, and from
   now on hvp->apic_assist belongs to the original "normal" SPA page;
2. the remaining work of stopping this CPU is done
3. this CPU is completely stopped.

Between 1 and 3, this CPU can still receive interrupts (e.g. reschedule
IPIs from CPU0, and Local APIC timer interrupts), and this CPU *must* write
the EOI MSR for every interrupt received, otherwise the hypervisor may not
deliver further interrupts, which may be needed to completely stop the CPU.

So, after the EOI optimization is disabled in hv_cpu_die(), it's required
that the hvp->apic_assist's bit0 is zero, which is not guaranteed by the
current allocation mode because it lacks __GFP_ZERO. As a consequence the
bit might be set and interrupt handling would not write the EOI MSR causing
interrupt delivery to become stuck.

Add the missing __GFP_ZERO to the allocation.

Note 1: after the "normal" SPA page is allocted and zeroed out, neither the
hypervisor nor the guest writes into the page, so the page remains with
zeros.

Note 2: see Section 10.3.5 "EOI Assist" for the details of the EOI
optimization. When the optimization is enabled, the guest can still write
the EOI MSR register irrespective of the "No EOI required" value, but
that's slower than the optimized assist based variant.

Fixes: ba696429 ("x86/hyper-v: Implement EOI assist")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/ <PU1P153MB0169B716A637FABF07433C04BFCB0@PU1P153MB0169.APCP153.PROD.OUTLOOK.COM