Intel Xeon Phi processors (KNL and KNM) support PPIN as well, so add their
CPUIDs to the whitelist of supported processors.
Signed-off-by: NPiotr Luc <piotr.luc@intel.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170408172004.8463-1-piotr.luc@intel.com
Link: http://lkml.kernel.org/r/20170413201056.10525-1-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

This is just a defensive precaution: do not register notifiers with a
priority which would disrupt the error handling in the notifiers with
prio higher than MCE_PRIO_EDAC.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170327093304.10683-7-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Move all code relating to /dev/mcelog to a separate source file.
/dev/mcelog driver can now operate from the machine check notifier with
lowest prio.
Signed-off-by: NTony Luck <tony.luck@intel.com>
[ Move the mce_helper and trigger functionality behind CONFIG_X86_MCELOG_LEGACY. ]
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170327093304.10683-6-bp@alien8.de
[ Renamed CONFIG_X86_MCELOG to CONFIG_X86_MCELOG_LEGACY. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Introduce a simple data structure for collecting correctable errors
along with accessors. More detailed description in the code itself.

The error decoding is done with the decoding chain now and
mce_first_notifier() gets to see the error first and the CEC decides
whether to log it and then the rest of the chain doesn't hear about it -
basically the main reason for the CE collector - or to continue running
the notifiers.

When the CEC hits the action threshold, it will try to soft-offine the
page containing the ECC and then the whole decoding chain gets to see
the error.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170327093304.10683-5-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

It is confusing when staring at "struct mce_log mcelog" and then there's
also a function called mce_log(). So call the buffer what it is.

No functionality change.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170327093304.10683-4-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

We call it everywhere "struct mce *m". Adjust that here too to avoid
confusion.

No functionality change.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170327093304.10683-3-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Since:

  cd9c57ca ("x86/MCE: Dump MCE to dmesg if no consumers")

all MCEs are printed even when mcelog is running. Fix the regression to
not print to dmesg when mcelog is running as it is a consumer too.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
[ Massage commit message. ]
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: stable@vger.kernel.org # 4.10..
Fixes: cd9c57ca ("x86/MCE: Dump MCE to dmesg if no consumers")
Link: http://lkml.kernel.org/r/20170327093304.10683-2-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

When the MCA banks in __mcheck_cpu_init_generic() are polled for leftover
errors logged during boot or from the previous boot, its required to have
CPU features detected sufficiently so that the reading out and handling of
those early errors is done correctly.

If those features are not available, the decoding may miss some information
and get incomplete errors logged. For example, on SMCA systems the MCA_IPID
and MCA_SYND registers are not logged and MCA_ADDR is not masked
appropriately.

To cure that, do a subset of the basic feature detection early while the
rest happens in its usual place in __mcheck_cpu_init_vendor().
Signed-off-by: NYazen Ghannam <Yazen.Ghannam@amd.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/1489599055-20756-1-git-send-email-Yazen.Ghannam@amd.com
[ Massage commit message and simplify. ]
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The rdtgroup_kn_unlock waits for the last user to release and put its
node. But it's calling kernfs_put on the node which calls the
rdtgroup_kn_unlock, which might not be the group's directory node, but
another group's file node.

This race could be easily reproduced by running 2 instances
of following script:

  mount -t resctrl resctrl /sys/fs/resctrl/
  pushd /sys/fs/resctrl/
  mkdir krava
  echo "krava" > krava/schemata
  rmdir krava
  popd
  umount  /sys/fs/resctrl

It triggers the slub debug error message with following command
line config: slub_debug=,kernfs_node_cache.

Call kernfs_put on the group's node to fix it.

Fixes: 60cf5e10 ("x86/intel_rdt: Add mkdir to resctrl file system")
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Shaohua Li <shli@fb.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1489501253-20248-1-git-send-email-jolsa@kernel.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

When we are about to kexec a crash kernel and right then and there a
broadcasted MCE fires while we're still in the first kernel and while
the other CPUs remain in a holding pattern, the #MC handler of the
first kernel will timeout and then panic due to never completing MCE
synchronization.

Handle this in a similar way as to when the CPUs are offlined when that
broadcasted MCE happens.

[ Boris: rewrote commit message and comments. ]
Suggested-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NXunlei Pang <xlpang@redhat.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NTony Luck <tony.luck@intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: kexec@lists.infradead.org
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1487857012-9059-1-git-send-email-xlpang@redhat.com
Link: http://lkml.kernel.org/r/20170313095019.19351-1-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Move the following task->mm helper APIs into a new header file,
<linux/sched/mm.h>, to further reduce the size and complexity
of <linux/sched.h>.

Here are how the APIs are used in various kernel files:

  # mm_alloc():
  arch/arm/mach-rpc/ecard.c
  fs/exec.c
  include/linux/sched/mm.h
  kernel/fork.c

  # __mmdrop():
  arch/arc/include/asm/mmu_context.h
  include/linux/sched/mm.h
  kernel/fork.c

  # mmdrop():
  arch/arm/mach-rpc/ecard.c
  arch/m68k/sun3/mmu_emu.c
  arch/x86/mm/tlb.c
  drivers/gpu/drm/amd/amdkfd/kfd_process.c
  drivers/gpu/drm/i915/i915_gem_userptr.c
  drivers/infiniband/hw/hfi1/file_ops.c
  drivers/vfio/vfio_iommu_spapr_tce.c
  fs/exec.c
  fs/proc/base.c
  fs/proc/task_mmu.c
  fs/proc/task_nommu.c
  fs/userfaultfd.c
  include/linux/mmu_notifier.h
  include/linux/sched/mm.h
  kernel/fork.c
  kernel/futex.c
  kernel/sched/core.c
  mm/khugepaged.c
  mm/ksm.c
  mm/mmu_context.c
  mm/mmu_notifier.c
  mm/oom_kill.c
  virt/kvm/kvm_main.c

  # mmdrop_async_fn():
  include/linux/sched/mm.h

  # mmdrop_async():
  include/linux/sched/mm.h
  kernel/fork.c

  # mmget_not_zero():
  fs/userfaultfd.c
  include/linux/sched/mm.h
  mm/oom_kill.c

  # mmput():
  arch/arc/include/asm/mmu_context.h
  arch/arc/kernel/troubleshoot.c
  arch/frv/mm/mmu-context.c
  arch/powerpc/platforms/cell/spufs/context.c
  arch/sparc/include/asm/mmu_context_32.h
  drivers/android/binder.c
  drivers/gpu/drm/etnaviv/etnaviv_gem.c
  drivers/gpu/drm/i915/i915_gem_userptr.c
  drivers/infiniband/core/umem.c
  drivers/infiniband/core/umem_odp.c
  drivers/infiniband/core/uverbs_main.c
  drivers/infiniband/hw/mlx4/main.c
  drivers/infiniband/hw/mlx5/main.c
  drivers/infiniband/hw/usnic/usnic_uiom.c
  drivers/iommu/amd_iommu_v2.c
  drivers/iommu/intel-svm.c
  drivers/lguest/lguest_user.c
  drivers/misc/cxl/fault.c
  drivers/misc/mic/scif/scif_rma.c
  drivers/oprofile/buffer_sync.c
  drivers/vfio/vfio_iommu_type1.c
  drivers/vhost/vhost.c
  drivers/xen/gntdev.c
  fs/exec.c
  fs/proc/array.c
  fs/proc/base.c
  fs/proc/task_mmu.c
  fs/proc/task_nommu.c
  fs/userfaultfd.c
  include/linux/sched/mm.h
  kernel/cpuset.c
  kernel/events/core.c
  kernel/events/uprobes.c
  kernel/exit.c
  kernel/fork.c
  kernel/ptrace.c
  kernel/sys.c
  kernel/trace/trace_output.c
  kernel/tsacct.c
  mm/memcontrol.c
  mm/memory.c
  mm/mempolicy.c
  mm/migrate.c
  mm/mmu_notifier.c
  mm/nommu.c
  mm/oom_kill.c
  mm/process_vm_access.c
  mm/rmap.c
  mm/swapfile.c
  mm/util.c
  virt/kvm/async_pf.c

  # mmput_async():
  include/linux/sched/mm.h
  kernel/fork.c
  mm/oom_kill.c

  # get_task_mm():
  arch/arc/kernel/troubleshoot.c
  arch/powerpc/platforms/cell/spufs/context.c
  drivers/android/binder.c
  drivers/gpu/drm/etnaviv/etnaviv_gem.c
  drivers/infiniband/core/umem.c
  drivers/infiniband/core/umem_odp.c
  drivers/infiniband/hw/mlx4/main.c
  drivers/infiniband/hw/mlx5/main.c
  drivers/infiniband/hw/usnic/usnic_uiom.c
  drivers/iommu/amd_iommu_v2.c
  drivers/iommu/intel-svm.c
  drivers/lguest/lguest_user.c
  drivers/misc/cxl/fault.c
  drivers/misc/mic/scif/scif_rma.c
  drivers/oprofile/buffer_sync.c
  drivers/vfio/vfio_iommu_type1.c
  drivers/vhost/vhost.c
  drivers/xen/gntdev.c
  fs/proc/array.c
  fs/proc/base.c
  fs/proc/task_mmu.c
  include/linux/sched/mm.h
  kernel/cpuset.c
  kernel/events/core.c
  kernel/exit.c
  kernel/fork.c
  kernel/ptrace.c
  kernel/sys.c
  kernel/trace/trace_output.c
  kernel/tsacct.c
  mm/memcontrol.c
  mm/memory.c
  mm/mempolicy.c
  mm/migrate.c
  mm/mmu_notifier.c
  mm/nommu.c
  mm/util.c

  # mm_access():
  fs/proc/base.c
  include/linux/sched/mm.h
  kernel/fork.c
  mm/process_vm_access.c

  # mm_release():
  arch/arc/include/asm/mmu_context.h
  fs/exec.c
  include/linux/sched/mm.h
  include/uapi/linux/sched.h
  kernel/exit.c
  kernel/fork.c
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Wanpeng Li reported that since the following commit:

  acb04058 ("sched/clock: Fix hotplug crash")

... KVM always runs with unstable sched-clock even though KVM's
kvm_clock _is_ stable.

The problem is that we've tied clear_sched_clock_stable() to the TSC
state, and overlooked that sched_clock() is a paravirt function.

Solve this by doing two things:

 - tie the sched_clock() stable state more clearly to the TSC stable
   state for the normal (!paravirt) case.

 - only call clear_sched_clock_stable() when we mark TSC unstable
   when we use native_sched_clock().

The first means we can actually run with stable sched_clock in more
situations then before, which is good. And since commit:

  12907fbb ("sched/clock, clocksource: Add optional cs::mark_unstable() method")

... this should be reliable. Since any detection of TSC fail now results
in marking the TSC unstable.
Reported-by: NWanpeng Li <kernellwp@gmail.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Fixes: acb04058 ("sched/clock: Fix hotplug crash")
Signed-off-by: NIngo Molnar <mingo@kernel.org>

sched/headers: Prepare to move 'init_task' and 'init_thread_union' from <linux/sched.h> to <linux/sched/task.h>

Update all usage sites first.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

We are going to split <linux/sched/clock.h> out of <linux/sched.h>, which
will have to be picked up from other headers and .c files.

Create a trivial placeholder <linux/sched/clock.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Cc: fenghua.yu@intel.com
Link: http://lkml.kernel.org/r/20170227130703.26968-1-standby24x7@gmail.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Cc: akataria@vmware.com
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/20170227122922.26230-1-standby24x7@gmail.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:

  git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
  git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'

This is needed for a later patch that hooks into the helper, but might
be a worthwhile cleanup on its own.

(Michal Hocko provided most of the kerneldoc comment.)

Link: http://lkml.kernel.org/r/20161218123229.22952-1-vegard.nossum@oracle.comSigned-off-by: NVegard Nossum <vegard.nossum@oracle.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After:

  a33d3317 ("x86/CPU/AMD: Fix Bulldozer topology")

our  SMT scheduling topology for Fam17h systems is broken, because
the ThreadId is included in the ApicId when SMT is enabled.

So, without further decoding cpu_core_id is unique for each thread
rather than the same for threads on the same core. This didn't affect
systems with SMT disabled. Make cpu_core_id be what it is defined to be.
Signed-off-by: NYazen Ghannam <Yazen.Ghannam@amd.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.9
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/20170205105022.8705-2-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Commit:

  a33d3317 ("x86/CPU/AMD: Fix Bulldozer topology")

restored the initial approach we had with the Fam15h topology of
enumerating CU (Compute Unit) threads as cores. And this is still
correct - they're beefier than HT threads but still have some
shared functionality.

Our current approach has a problem with the Mad Max Steam game, for
example. Yves Dionne reported a certain "choppiness" while playing on
v4.9.5.

That problem stems most likely from the fact that the CU threads share
resources within one CU and when we schedule to a thread of a different
compute unit, this incurs latency due to migrating the working set to a
different CU through the caches.

When the thread siblings mask mirrors that aspect of the CUs and
threads, the scheduler pays attention to it and tries to schedule within
one CU first. Which takes care of the latency, of course.
Reported-by: NYves Dionne <yves.dionne@gmail.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.9
Cc: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yazen Ghannam <yazen.ghannam@amd.com>
Link: http://lkml.kernel.org/r/20170205105022.8705-1-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Enable ring 3 MONITOR/MWAIT for Intel Xeon Phi codenamed Knights Mill. We
can't guarantee that this (KNM) will be the last CPU model that needs this
hack.  But, we do recognize that this is far from optimal, and there is an
effort to ensure we don't keep doing extending this hack forever.
Signed-off-by: NPiotr Luc <piotr.luc@intel.com>
Cc: Piotr.Luc@intel.com
Cc: dave.hansen@linux.intel.com
Link: http://lkml.kernel.org/r/1484918557-15481-6-git-send-email-grzegorz.andrejczuk@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Enable ring 3 MONITOR/MWAIT for Intel Xeon Phi x200 codenamed Knights
Landing.

Presence of this feature cannot be detected automatically (by reading any
other MSR) therefore it is required to explicitly check for the family and
model of the CPU before attempting to enable it.
Signed-off-by: NGrzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
Cc: Piotr.Luc@intel.com
Cc: dave.hansen@linux.intel.com
Link: http://lkml.kernel.org/r/1484918557-15481-5-git-send-email-grzegorz.andrejczuk@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Introduce ELF_HWCAP2 variable for x86 and reserve its bit 0 to expose the
ring 3 MONITOR/MWAIT.

HWCAP variables contain bitmasks which can be used by userspace
applications to detect which instruction sets are supported by CPU.  On x86
architecture information about CPU capabilities can be checked via CPUID
instructions, unfortunately presence of ring 3 MONITOR/MWAIT feature cannot
be checked this way. ELF_HWCAP cannot be used as well, because on x86 it is
set to CPUID[1].EDX which means that all bits are reserved there.

HWCAP2 approach was chosen because it reuses existing solution present
in other architectures, so only minor modifications are required to the
kernel and userspace applications. When ELF_HWCAP2 is defined
kernel maps it to AT_HWCAP2 during the start of the application.
This way the ring 3 MONITOR/MWAIT feature can be detected using getauxval()
API in a simple and fast manner. ELF_HWCAP2 type is u32 to be consistent
with x86 ELF_HWCAP type.
Signed-off-by: NGrzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
Cc: Piotr.Luc@intel.com
Cc: dave.hansen@linux.intel.com
Link: http://lkml.kernel.org/r/1484918557-15481-3-git-send-email-grzegorz.andrejczuk@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Erik reported that on a preproduction hardware a CMCI storm triggers the
BUG_ON in add_timer_on(). The reason is that the per CPU MCE timer is
started by the CMCI logic before the MCE CPU hotplug callback starts the
timer with add_timer_on(). So the timer is already queued which triggers
the BUG.

Using add_timer_on() is pretty pointless in this code because the timer is
strictlty per CPU, initialized as pinned and all operations which arm the
timer happen on the CPU to which the timer belongs.

Simplify the whole machinery by using mod_timer() instead of add_timer_on()
which avoids the problem because mod_timer() can handle already queued
timers. Use __start_timer() everywhere so the earliest armed expiry time is
preserved.
Reported-by: NErik Veijola <erik.veijola@intel.com>
Tested-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NBorislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanosSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

When we look for microcode blobs, we first try builtin and if that
doesn't succeed, we fallback to the initrd supplied to the kernel.

However, at some point doing boot, that initrd gets jettisoned and we
shouldn't access it anymore. But we do, as the below KASAN report shows.
That's because find_microcode_in_initrd() doesn't check whether the
initrd is still valid or not.

So do that.

  ==================================================================
  BUG: KASAN: use-after-free in find_cpio_data
  Read of size 1 by task swapper/1/0
  page:ffffea0000db9d40 count:0 mapcount:0 mapping:          (null) index:0x1
  flags: 0x100000000000000()
  raw: 0100000000000000 0000000000000000 0000000000000001 00000000ffffffff
  raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000
  page dumped because: kasan: bad access detected
  CPU: 1 PID: 0 Comm: swapper/1 Tainted: G        W       4.10.0-rc5-debug-00075-g2dbde22 #3
  Hardware name: Dell Inc. XPS 13 9360/0839Y6, BIOS 1.2.3 12/01/2016
  Call Trace:
   dump_stack
   ? _atomic_dec_and_lock
   ? __dump_page
   kasan_report_error
   ? pointer
   ? find_cpio_data
   __asan_report_load1_noabort
   ? find_cpio_data
   find_cpio_data
   ? vsprintf
   ? dump_stack
   ? get_ucode_user
   ? print_usage_bug
   find_microcode_in_initrd
   __load_ucode_intel
   ? collect_cpu_info_early
   ? debug_check_no_locks_freed
   load_ucode_intel_ap
   ? collect_cpu_info
   ? trace_hardirqs_on
   ? flat_send_IPI_mask_allbutself
   load_ucode_ap
   ? get_builtin_firmware
   ? flush_tlb_func
   ? do_raw_spin_trylock
   ? cpumask_weight
   cpu_init
   ? trace_hardirqs_off
   ? play_dead_common
   ? native_play_dead
   ? hlt_play_dead
   ? syscall_init
   ? arch_cpu_idle_dead
   ? do_idle
   start_secondary
   start_cpu
  Memory state around the buggy address:
   ffff880036e74f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
   ffff880036e74f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  >ffff880036e75000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                     ^
   ffff880036e75080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
   ffff880036e75100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  ==================================================================
Reported-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Tested-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
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/20170126165833.evjemhbqzaepirxo@pd.tnicSigned-off-by: NIngo Molnar <mingo@kernel.org>

Calling get_cpu_cap() will reset a bunch of CPU features.  This will
cause the system to lose track of force-set and force-cleared
features in the words that are reset until the end of CPU
initialization.  This can cause X86_FEATURE_FPU, for example, to
change back and forth during boot and potentially confuse CPU setup.

To minimize the chance of confusion, re-apply forced caps every time
get_cpu_cap() is called.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Reviewed-by: NBorislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Whitehead <tedheadster@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/c817eb373d2c67c2c81413a70fc9b845fa34a37e.1484705016.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

There are multiple call sites that apply forced CPU caps.  Factor
them into a helper.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Reviewed-by: NBorislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Whitehead <tedheadster@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/623ff7555488122143e4417de09b18be2085ad06.1484705016.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add a synthetic CPUID flag denoting whether the CPU sports the CPUID
instruction or not. This will come useful later when accomodating
CPUID-less CPUs.
Signed-off-by: NBorislav Petkov <bp@suse.de>
[ Slightly prettified. ]
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Reviewed-by: NBorislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Whitehead <tedheadster@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/dcb355adae3ab812c79397056a61c212f1a0c7cc.1484705016.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Assign all notifiers on the MCE decode chain a priority so that they get
called in the correct order.
Suggested-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170123183514.13356-10-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Make mce_gen_pool_process() the workqueue function directly and save us
an indirection.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170123183514.13356-9-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add the TSC value to the MCE record only when the MCE being logged is
precise, i.e., it is logged as an exception or an MCE-related interrupt.

So it doesn't look particularly easy to do without touching/changing a
bunch of places. That's why I'm trying tricks first.

For example, the mce-apei.c case I'm addressing by setting ->tsc only
for errors of panic severity. The idea there is, that, panic errors will
have raised an #MC and not polled.

And then instead of propagating a flag to mce_setup(), it seems
easier/less code to set ->tsc depending on the call sites, i.e.,
are we polling or are we preparing an MCE record in an exception
handler/thresholding interrupt.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170123183514.13356-5-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently, we append the MCA_IPID[InstanceId] to the bank name to create
the sysfs filename. The InstanceId field uniquely identifies a bank
instance but it doesn't look very nice for most banks.

Replace the InstanceId with a simpler, ascending (0, 1, ..) value.
Only use this in the sysfs name when there is more than 1 instance.
Otherwise, just use the bank's name as the sysfs name.
Signed-off-by: NYazen Ghannam <Yazen.Ghannam@amd.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1484322741-41884-3-git-send-email-Yazen.Ghannam@amd.com
Link: http://lkml.kernel.org/r/20170123183514.13356-4-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

We log a fake bank 128 MCE to note that we're handling a CPU thermal
event. However, this confuses people into thinking that their hardware
generates MCEs. Hijacking MCA for logging thermal events is a gross
misuse anyway and it shouldn't have been done in the first place. And
besides we have other means for dealing with thermal events which are
much more suitable.

So let's kill the MCE logging part.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NAshok Raj <ashok.raj@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170105213846.GA12024@gmail.com
Link: http://lkml.kernel.org/r/20170123183514.13356-3-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

... and get rid of the annoying:

  arch/x86/kernel/cpu/mcheck/mce-inject.c:97:13: warning: ‘mce_irq_ipi’ defined but not used [-Wunused-function]

when doing randconfig builds.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170123183514.13356-2-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

The equivalence ID was needed outside of the container scanning logic
but now, after this has been cleaned up, not anymore. Now, cont_desc.mc
is used to denote whether the container we're looking at has the proper
microcode patch for this CPU or not.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-17-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

The idea was to not scan the microcode blob on each AP (Application
Processor) during boot and thus save us some milliseconds. However, on
architectures where the microcode engine is shared between threads, this
doesn't work. Here's why:

The microcode on CPU0, i.e., the first thread, gets updated. The second
thread, i.e., CPU1, i.e., the first AP walks into load_ucode_amd_ap(),
sees that there's no container cached and goes and scans for the proper
blob.

It finds it and as a last step of apply_microcode_early_amd(), it tries
to apply the patch but that core has already the updated microcode
revision which it has received through CPU0's update. So it returns
false and we do desc->size = -1 to prevent other APs from scanning.

However, the next AP, CPU2, has a different microcode engine which
hasn't been updated yet. The desc->size == -1 test prevents it from
scanning the blob anew and we fail to update it.

The fix is much more straight-forward than it looks: the BSP
(BootStrapping Processor), i.e., CPU0, caches the microcode patch
in amd_ucode_patch. We use that on the AP and try to apply it.
In the 99.9999% of cases where we have homogeneous cores - *not*
mixed-steppings - the application will be successful and we're good to
go.

In the remaining small set of systems, we will simply rescan the blob
and find (or not, if none present) the proper patch and apply it then.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-16-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

No need to use the previously stashed info in the container - simply go
ahead and parse the initrd once more. It simplifies and streamlines the
code a whole lot.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-15-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Use a version for both bitness by adding a helper which does the actual
container finding and parsing which can be used on any CPU - BSP or AP.
Streamlines the paths more.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-14-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>