The SLB bad address handler's trap number fixup does not preserve the
low bit that indicates nonvolatile GPRs have not been saved. This
leads save_nvgprs to skip saving them, and subsequent functions and
return from interrupt will think they are saved.

This causes kernel branch-to-garbage debugging to not have correct
registers, can also cause userspace to have its registers clobbered
after a segfault.

Fixes: f0f558b131db ("powerpc/mm: Preserve CFAR value on SLB miss caused by access to bogus address")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

On POWER9, under some circumstances, a broadcast TLB invalidation
might complete before all previous stores have drained, potentially
allowing stale stores from becoming visible after the invalidation.
This works around it by doubling up those TLB invalidations which was
verified by HW to be sufficient to close the risk window.

This will be documented in a yet-to-be-published errata.

Fixes: 1a472c9dba6b ("powerpc/mm/radix: Add tlbflush routines")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Enable the feature in the DT CPU features code for all Power9,
      rename the feature to CPU_FTR_P9_TLBIE_BUG per benh.]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

force_external_irq_replay() can be called in the do_IRQ path with
interrupts hard enabled and soft disabled if may_hard_irq_enable() set
MSR[EE]=1. It updates local_paca->irq_happened with a load, modify,
store sequence. If a maskable interrupt hits during this sequence, it
will go to the masked handler to be marked pending in irq_happened.
This update will be lost when the interrupt returns and the store
instruction executes. This can result in unpredictable latencies,
timeouts, lockups, etc.

Fix this by ensuring hard interrupts are disabled before modifying
irq_happened.

This could cause any maskable asynchronous interrupt to get lost, but
it was noticed on P9 SMP system doing RDMA NVMe target over 100GbE,
so very high external interrupt rate and high IPI rate. The hang was
bisected down to enabling doorbell interrupts for IPIs. These provided
an interrupt type that could run at high rates in the do_IRQ path,
stressing the race.

Fixes: 1d607bb3bd60 ("powerpc/irq: Add mechanism to force a replay of interrupts")
Cc: stable@vger.kernel.org # v4.8+
Reported-by: Carol L. Soto <clsoto@us.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When running virtualised the powerpc kernel is able to run the system
in "compat mode" - which means the kernel and hardware are pretending
to userspace that the CPU is an older version than it actually is.

AT_BASE_PLATFORM is an AUXV entry that we export to userspace for use
when we're running in that mode, which tells userspace the "platform"
string for the real CPU version, as opposed to the faked version.

Although we don't support compat mode when using DT CPU features, and
arguably don't need to set AT_BASE_PLATFORM, the existing cputable
based code always sets it even when we're running bare metal. That
means the lack of AT_BASE_PLATFORM is a user-visible artifact of the
fact that the kernel is using DT CPU features, which we don't want.

So set it in the DT CPU features code also.

This results in eg:
  $ LD_SHOW_AUXV=1 /bin/true | grep "AT_.*PLATFORM"
  AT_PLATFORM:     power9
  AT_BASE_PLATFORM:power9

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

With ibm,dynamic-memory-v2 and ibm,drc-info coming around the same
time, byte22 in vector5 of ibm architecture vector table got set twice
separately. The end result is that guest kernel isn't advertising
support for ibm,dynamic-memory-v2.

Fix this by removing the duplicate assignment of byte22.

Fixes: 02ef6dd8109b ("powerpc: Enable support for ibm,drc-info devtree property")
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This reverts commit 02ef6dd8109b581343ebeb1c4c973513682535d6.

The earlier patch tried to enable support for a new property
"ibm,drc-info" on powerpc systems.

Unfortunately, some errors in the associated patch set break things
in some of the DLPAR operations.  In particular when attempting to
hot-add a new CPU or set of CPUs, the original patch failed to
properly calculate the available resources, and aborted the operation.
In addition, the original set missed several opportunities to compress
and reuse common code.

As the associated patch set was meant to provide an optimization of
storage and performance of a set of device-tree properties for future
systems with large amounts of resources, reverting just restores
the previous behavior for existing systems.  It seems unnecessary
to enable this feature and introduce the consequent problems in the
field that it will cause at this time, so please revert it for now
until testing of the corrections are finished properly.

Fixes: 02ef6dd8109b ("powerpc: Enable support for ibm,drc-info devtree property")
Signed-off-by: Michael W. Bringmann <mwb@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The notify_resume() callback in eeh_ops is NULL on powernv, leading to
crashes:

  NIP (null)
  LR  eeh_report_resume+0x218/0x220
  Call Trace:
   eeh_report_resume+0x1f0/0x220 (unreliable)
   eeh_pe_dev_traverse+0x98/0x170
   eeh_handle_normal_event+0x3f4/0x650
   eeh_handle_event+0x54/0x380
   eeh_event_handler+0x14c/0x210
   kthread+0x168/0x1b0
   ret_from_kernel_thread+0x5c/0xb4

Fix it by adding a check before calling it.

Fixes: 856e1eb9bdd4 ("PCI/AER: Add uevents in AER and EEH error/resume")
Signed-off-by: Juan J. Alvarez <jjalvare@linux.vnet.ibm.com>
Reviewed-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Tested-by: Carol L. Soto <clsoto@us.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Tested-by: Mauro S. M. Rodrigues <maurosr@linux.vnet.ibm.com>
Acked-by: Michael Neuling <mikey@neuling.org>
[mpe: Rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The TSCR can only be accessed in hypervisor mode.

Fixes: 88b5e12eeb11 ("powerpc: Expose TSCR via sysfs")
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Pull powerpc fixes from Michael Ellerman:
 "A larger batch of fixes than we'd like. Roughly 1/3 fixes for new
  code, 1/3 fixes for stable and 1/3 minor things.

  There's four commits fixing bugs when using 16GB huge pages on hash,
  caused by some of the preparatory changes for pkeys.

  Two fixes for bugs in the enhanced IRQ soft masking for local_t, one
  of which broke KVM in some circumstances.

  Four fixes for Power9. The most bizarre being a bug where futexes
  stopped working because a NULL pointer dereference didn't trap during
  early boot (it aliased the kernel mapping). A fix for memory hotplug
  when using the Radix MMU, and a fix for live migration of guests using
  the Radix MMU.

  Two fixes for hotplug on pseries machines. One where we weren't
  correctly updating NUMA info when CPUs are added and removed. And the
  other fixes crashes/hangs seen when doing memory hot remove during
  boot, which is apparently a thing people do.

  Finally a handful of build fixes for obscure configs and other minor
  fixes.

  Thanks to: Alexey Kardashevskiy, Aneesh Kumar K.V, Balbir Singh, Colin
  Ian King, Daniel Henrique Barboza, Florian Weimer, Guenter Roeck,
  Harish, Laurent Vivier, Madhavan Srinivasan, Mauricio Faria de
  Oliveira, Nathan Fontenot, Nicholas Piggin, Sam Bobroff"

* tag 'powerpc-4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  selftests/powerpc: Fix to use ucontext_t instead of struct ucontext
  powerpc/kdump: Fix powernv build break when KEXEC_CORE=n
  powerpc/pseries: Fix build break for SPLPAR=n and CPU hotplug
  powerpc/mm/hash64: Zero PGD pages on allocation
  powerpc/mm/hash64: Store the slot information at the right offset for hugetlb
  powerpc/mm/hash64: Allocate larger PMD table if hugetlb config is enabled
  powerpc/mm: Fix crashes with 16G huge pages
  powerpc/mm: Flush radix process translations when setting MMU type
  powerpc/vas: Don't set uses_vas for kernel windows
  powerpc/pseries: Enable RAS hotplug events later
  powerpc/mm/radix: Split linear mapping on hot-unplug
  powerpc/64s/radix: Boot-time NULL pointer protection using a guard-PID
  ocxl: fix signed comparison with less than zero
  powerpc/64s: Fix may_hard_irq_enable() for PMI soft masking
  powerpc/64s: Fix MASKABLE_RELON_EXCEPTION_HV_OOL macro
  powerpc/numa: Invalidate numa_cpu_lookup_table on cpu remove

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>