P9 DD2 NX workbook (Table 4-36) says DMA controller uses CC=5
internally for translation fault handling. NX reserves CC=250 for
OS to notify user space when NX encounters address translation
failure on the request buffer. Not an issue in earlier releases
as NX does not get faults on kernel addresses.

This patch defines CSB_CC_FAULT_ADDRESS(250) and updates CSB.CC with
this proper error code for user space.

Fixes: c96c4436aba4 ("powerpc/vas: Update CSB and notify process for fault CRBs")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
[mpe: Added Fixes tag and fix typo in comment]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/019fd53e7538c6f8f332d175df74b1815ef5aa8c.camel@linux.ibm.com

Pull powerpc fixes from Michael Ellerman:

 - One fix for the interrupt rework we did last release which broke
   KVM-PR

 - Three commits fixing some fallout from the READ_ONCE() changes
   interacting badly with our 8xx 16K pages support, which uses a pte_t
   that is a structure of 4 actual PTEs

 - A cleanup of the 8xx pte_update() to use the newly added pmd_off()

 - A fix for a crash when handling an oops if CONFIG_DEBUG_VIRTUAL is
   enabled

 - A minor fix for the SPU syscall generation

Thanks to Aneesh Kumar K.V, Christian Zigotzky, Christophe Leroy, Mike
Rapoport, Nicholas Piggin.

* tag 'powerpc-5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/8xx: Provide ptep_get() with 16k pages
  mm: Allow arches to provide ptep_get()
  mm/gup: Use huge_ptep_get() in gup_hugepte()
  powerpc/syscalls: Use the number when building SPU syscall table
  powerpc/8xx: use pmd_off() to access a PMD entry in pte_update()
  powerpc/64s: Fix KVM interrupt using wrong save area
  powerpc: Fix kernel crash in show_instructions() w/DEBUG_VIRTUAL

Pull libnvdimm updates from Dan Williams:
 "A feature (papr_scm health retrieval) and a fix (sysfs attribute
  visibility) for v5.8.

  Vaibhav explains in the merge commit below why missing v5.8 would be
  painful and I agreed to try a -rc2 pull because only cosmetics kept
  this out of -rc1 and his initial versions were posted in more than
  enough time for v5.8 consideration:

   'These patches are tied to specific features that were committed to
    customers in upcoming distros releases (RHEL and SLES) whose
    time-lines are tied to 5.8 kernel release.

    Being able to track the health of an nvdimm is critical for our
    customers that are running workloads leveraging papr-scm nvdimms.
    Missing the 5.8 kernel would mean missing the distro timelines and
    shifting forward the availability of this feature in distro kernels
    by at least 6 months'

  Summary:

   - Fix the visibility of the region 'align' attribute.

     The new unit tests for region alignment handling caught a corner
     case where the alignment cannot be specified if the region is
     converted from static to dynamic provisioning at runtime.

   - Add support for device health retrieval for the persistent memory
     supported by the papr_scm driver.

     This includes both the standard sysfs "health flags" that the nfit
     persistent memory driver publishes and a mechanism for the ndctl
     tool to retrieve a health-command payload"

* tag 'libnvdimm-for-5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  nvdimm/region: always show the 'align' attribute
  powerpc/papr_scm: Implement support for PAPR_PDSM_HEALTH
  ndctl/papr_scm,uapi: Add support for PAPR nvdimm specific methods
  powerpc/papr_scm: Improve error logging and handling papr_scm_ndctl()
  powerpc/papr_scm: Fetch nvdimm health information from PHYP
  seq_buf: Export seq_buf_printf
  powerpc: Document details on H_SCM_HEALTH hcall

READ_ONCE() now enforces atomic read, which leads to:

  CC      mm/gup.o
In file included from ./include/linux/kernel.h:11:0,
                 from mm/gup.c:2:
In function 'gup_hugepte.constprop',
    inlined from 'gup_huge_pd.isra.79' at mm/gup.c:2465:8:
./include/linux/compiler.h:392:38: error: call to '__compiletime_assert_222' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE().
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
                                      ^
./include/linux/compiler.h:373:4: note: in definition of macro '__compiletime_assert'
    prefix ## suffix();    \
    ^
./include/linux/compiler.h:392:2: note: in expansion of macro '_compiletime_assert'
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
  ^
./include/linux/compiler.h:405:2: note: in expansion of macro 'compiletime_assert'
  compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
  ^
./include/linux/compiler.h:291:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
  compiletime_assert_rwonce_type(x);    \
  ^
mm/gup.c:2428:8: note: in expansion of macro 'READ_ONCE'
  pte = READ_ONCE(*ptep);
        ^
In function 'gup_get_pte',
    inlined from 'gup_pte_range' at mm/gup.c:2228:9,
    inlined from 'gup_pmd_range' at mm/gup.c:2613:15,
    inlined from 'gup_pud_range' at mm/gup.c:2641:15,
    inlined from 'gup_p4d_range' at mm/gup.c:2666:15,
    inlined from 'gup_pgd_range' at mm/gup.c:2694:15,
    inlined from 'internal_get_user_pages_fast' at mm/gup.c:2795:3:
./include/linux/compiler.h:392:38: error: call to '__compiletime_assert_219' declared with attribute error: Unsupported access size for {READ,WRITE}_ONCE().
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
                                      ^
./include/linux/compiler.h:373:4: note: in definition of macro '__compiletime_assert'
    prefix ## suffix();    \
    ^
./include/linux/compiler.h:392:2: note: in expansion of macro '_compiletime_assert'
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
  ^
./include/linux/compiler.h:405:2: note: in expansion of macro 'compiletime_assert'
  compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
  ^
./include/linux/compiler.h:291:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
  compiletime_assert_rwonce_type(x);    \
  ^
mm/gup.c:2199:9: note: in expansion of macro 'READ_ONCE'
  return READ_ONCE(*ptep);
         ^
make[2]: *** [mm/gup.o] Error 1

Define ptep_get() on 8xx when using 16k pages.

Fixes: 9e343b467c70 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/341688399c1b102756046d19ea6ce39db1ae4742.1592225558.git.christophe.leroy@csgroup.eu

Now that we've renamed probe_kernel_address() to get_kernel_nofault()
and made it look and behave more in line with get_user(), some of the
subtle type behavior differences end up being more obvious and possibly
dangerous.

When you do

        get_user(val, user_ptr);

the type of the access comes from the "user_ptr" part, and the above
basically acts as

        val = *user_ptr;

by design (except, of course, for the fact that the actual dereference
is done with a user access).

Note how in the above case, the type of the end result comes from the
pointer argument, and then the value is cast to the type of 'val' as
part of the assignment.

So the type of the pointer is ultimately the more important type both
for the access itself.

But 'get_kernel_nofault()' may now _look_ similar, but it behaves very
differently.  When you do

        get_kernel_nofault(val, kernel_ptr);

it behaves like

        val = *(typeof(val) *)kernel_ptr;

except, of course, for the fact that the actual dereference is done with
exception handling so that a faulting access is suppressed and returned
as the error code.

But note how different the casting behavior of the two superficially
similar accesses are: one does the actual access in the size of the type
the pointer points to, while the other does the access in the size of
the target, and ignores the pointer type entirely.

Actually changing get_kernel_nofault() to act like get_user() is almost
certainly the right thing to do eventually, but in the meantime this
patch adds logit to at least verify that the pointer type is compatible
with the type of the result.

In many cases, this involves just casting the pointer to 'void *' to
make it obvious that the type of the pointer is not the important part.
It's not how 'get_user()' acts, but at least the behavioral difference
is now obvious and explicit.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Better describe what this helper does, and match the naming of
copy_from_kernel_nofault.

Also switch the argument order around, so that it acts and looks
like get_user().

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The pte_update() implementation for PPC_8xx unfolds page table from the PGD
level to access a PMD entry. Since 8xx has only 2-level page table this can
be simplified with pmd_off() shortcut.

Replace explicit unfolding with pmd_off() and drop defines of pgd_index()
and pgd_offset() that are no longer needed.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200615092229.23142-1-rppt@kernel.org

This patch implements support for PDSM request 'PAPR_PDSM_HEALTH'
that returns a newly introduced 'struct nd_papr_pdsm_health' instance
containing dimm health information back to user space in response to
ND_CMD_CALL. This functionality is implemented in newly introduced
papr_pdsm_health() that queries the nvdimm health information and
then copies this information to the package payload whose layout is
defined by 'struct nd_papr_pdsm_health'.

Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200615124407.32596-7-vaibhav@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Introduce support for PAPR NVDIMM Specific Methods (PDSM) in papr_scm
module and add the command family NVDIMM_FAMILY_PAPR to the white list
of NVDIMM command sets. Also advertise support for ND_CMD_CALL for the
nvdimm command mask and implement necessary scaffolding in the module
to handle ND_CMD_CALL ioctl and PDSM requests that we receive.

The layout of the PDSM request as we expect from libnvdimm/libndctl is
described in newly introduced uapi header 'papr_pdsm.h' which
defines a 'struct nd_pkg_pdsm' and a maximal union named
'nd_pdsm_payload'. These new structs together with 'struct nd_cmd_pkg'
for a pdsm envelop thats sent by libndctl to libnvdimm and serviced by
papr_scm in 'papr_scm_service_pdsm()'. The PDSM request is
communicated by member 'struct nd_cmd_pkg.nd_command' together with
other information on the pdsm payload (size-in, size-out).

The patch also introduces 'struct pdsm_cmd_desc' instances of which
are stored in an array __pdsm_cmd_descriptors[] indexed with PDSM cmd
and corresponding access function pdsm_cmd_desc() is
introduced. 'struct pdsm_cdm_desc' holds the service function for a
given PDSM and corresponding payload in/out sizes.

A new function papr_scm_service_pdsm() is introduced and is called from
papr_scm_ndctl() in case of a PDSM request is received via ND_CMD_CALL
command from libnvdimm. The function performs validation on the PDSM
payload based on info present in corresponding PDSM descriptor and if
valid calls the 'struct pdcm_cmd_desc.service' function to service the
PDSM.

Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200615124407.32596-6-vaibhav@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Pull more KVM updates from Paolo Bonzini:
 "The guest side of the asynchronous page fault work has been delayed to
  5.9 in order to sync with Thomas's interrupt entry rework, but here's
  the rest of the KVM updates for this merge window.

  MIPS:
   - Loongson port

  PPC:
   - Fixes

  ARM:
   - Fixes

  x86:
   - KVM_SET_USER_MEMORY_REGION optimizations
   - Fixes
   - Selftest fixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (62 commits)
  KVM: x86: do not pass poisoned hva to __kvm_set_memory_region
  KVM: selftests: fix sync_with_host() in smm_test
  KVM: async_pf: Inject 'page ready' event only if 'page not present' was previously injected
  KVM: async_pf: Cleanup kvm_setup_async_pf()
  kvm: i8254: remove redundant assignment to pointer s
  KVM: x86: respect singlestep when emulating instruction
  KVM: selftests: Don't probe KVM_CAP_HYPERV_ENLIGHTENED_VMCS when nested VMX is unsupported
  KVM: selftests: do not substitute SVM/VMX check with KVM_CAP_NESTED_STATE check
  KVM: nVMX: Consult only the "basic" exit reason when routing nested exit
  KVM: arm64: Move hyp_symbol_addr() to kvm_asm.h
  KVM: arm64: Synchronize sysreg state on injecting an AArch32 exception
  KVM: arm64: Make vcpu_cp1x() work on Big Endian hosts
  KVM: arm64: Remove host_cpu_context member from vcpu structure
  KVM: arm64: Stop sparse from moaning at __hyp_this_cpu_ptr
  KVM: arm64: Handle PtrAuth traps early
  KVM: x86: Unexport x86_fpu_cache and make it static
  KVM: selftests: Ignore KVM 5-level paging support for VM_MODE_PXXV48_4K
  KVM: arm64: Save the host's PtrAuth keys in non-preemptible context
  KVM: arm64: Stop save/restoring ACTLR_EL1
  KVM: arm64: Add emulation for 32bit guests accessing ACTLR2
  ...