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  1. 04 Mar, 2016 1 commit
  3. 03 Mar, 2016 1 commit
    • Ravi Bangoria's avatar
      powerpc/hw_breakpoint: Fix oops when destroying hw_breakpoint event · fb822e60
      Ravi Bangoria authored 
      When destroying a hw_breakpoint event, the kernel oopses as follows:

  Unable to handle kernel paging request for data at address 0x00000c07
  NIP [c0000000000291d0] arch_unregister_hw_breakpoint+0x40/0x60
  LR [c00000000020b6b4] release_bp_slot+0x44/0x80

Call chain:

  hw_breakpoint_event_init()
    bp->destroy = bp_perf_event_destroy;

  do_exit()
    perf_event_exit_task()
      perf_event_exit_task_context()
        WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
        perf_event_exit_event()
          free_event()
            _free_event()
              bp_perf_event_destroy() // event->destroy(event);
                release_bp_slot()
                  arch_unregister_hw_breakpoint()

perf_event_exit_task_context() sets child_ctx->task as TASK_TOMBSTONE
which is (void *)-1. arch_unregister_hw_breakpoint() tries to fetch
'thread' attribute of 'task' resulting in oops.

Peterz points out that the code shouldn't be using bp->ctx anyway, but
fixing that will require a decent amount of rework. So for now to fix
the oops, check if bp->ctx->task has been set to (void *)-1, before
dereferencing it. We don't use TASK_TOMBSTONE, because that would
require exporting it and it's supposed to be an internal detail.

Fixes: 63b6da39 ("perf: Fix perf_event_exit_task() race")
Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      fb822e60
  5. 29 Feb, 2016 1 commit
  7. 22 Feb, 2016 2 commits
    • Aneesh Kumar K.V's avatar
      powerpc/mm/hash: Clear the invalid slot information correctly · 9ab3ac23
      Aneesh Kumar K.V authored 
      We can get a hash pte fault with 4k base page size and find the pte
already inserted with 64K base page size. In that case we need to clear
the existing slot information from the old pte. Fix this correctly

With THP, we also clear the slot information with respect to all
the 64K hash pte mapping that 16MB page. They are all invalid
now. This make sure we don't find the slot valid when we fault with
4k base page size. Finding the slot valid should not result in any wrong
behavior because we do check again in hash page table for the validity.
But we can avoid that check completely.

Fixes: a43c0eb8 ("powerpc/mm: Convert 4k hash insert to C")
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      9ab3ac23
    • Gavin Shan's avatar
      powerpc/eeh: Fix partial hotplug criterion · f6bf0fa1
      Gavin Shan authored 
      During error recovery, the device could be removed as part of the
partial hotplug. The criterion used to come with partial hotplug
is: if the device driver provides error_detected(), slot_reset()
and resume() callbacks, it's immune from hotplug. Otherwise,
it's going to experience partial hotplug during EEH recovery. But
the criterion isn't correct enough: mlx4_core driver for Mellanox
adapters provides error_detected(), slot_reset() callbacks, but
resume() isn't there. Those Mellanox adapters won't be to involved
in the partial hotplug.

This fixes the criterion to a practical one: adpater with driver
that provides error_detected(), slot_reset() will be immune from
partial hotplug. resume() isn't mandatory.

Fixes: f2da4ccf ("powerpc/eeh: More relaxed hotplug criterion")
Cc: stable@vger.kernel.org #v4.4+
Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      f6bf0fa1
  9. 17 Feb, 2016 1 commit
  11. 15 Feb, 2016 4 commits
    • Aneesh Kumar K.V's avatar
      powerpc/mm: Fix Multi hit ERAT cause by recent THP update · c777e2a8
      Aneesh Kumar K.V authored 
      With ppc64 we use the deposited pgtable_t to store the hash pte slot
information. We should not withdraw the deposited pgtable_t without
marking the pmd none. This ensure that low level hash fault handling
will skip this huge pte and we will handle them at upper levels.

Recent change to pmd splitting changed the above in order to handle the
race between pmd split and exit_mmap. The race is explained below.

Consider following race:

		CPU0				CPU1
shrink_page_list()
  add_to_swap()
    split_huge_page_to_list()
      __split_huge_pmd_locked()
        pmdp_huge_clear_flush_notify()
	// pmd_none() == true
					exit_mmap()
					  unmap_vmas()
					    zap_pmd_range()
					      // no action on pmd since pmd_none() == true
	pmd_populate()

As result the THP will not be freed. The leak is detected by check_mm():

	BUG: Bad rss-counter state mm:ffff880058d2e580 idx:1 val:512

The above required us to not mark pmd none during a pmd split.

The fix for ppc is to clear the huge pte of _PAGE_USER, so that low
level fault handling code skip this pte. At higher level we do take ptl
lock. That should serialze us against the pmd split. Once the lock is
acquired we do check the pmd again using pmd_same. That should always
return false for us and hence we should retry the access. We do the
pmd_same check in all case after taking plt with
THP (do_huge_pmd_wp_page, do_huge_pmd_numa_page and
huge_pmd_set_accessed)

Also make sure we wait for irq disable section in other cpus to finish
before flipping a huge pte entry with a regular pmd entry. Code paths
like find_linux_pte_or_hugepte depend on irq disable to get
a stable pte_t pointer. A parallel thp split need to make sure we
don't convert a pmd pte to a regular pmd entry without waiting for the
irq disable section to finish.

Fixes: eef1b3ba ("thp: implement split_huge_pmd()")
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      c777e2a8
    • Gavin Shan's avatar
      powerpc/powernv: Fix stale PE primary bus · 1bc74f1c
      Gavin Shan authored 
      When PCI bus is unplugged during full hotplug for EEH recovery,
the platform PE instance (struct pnv_ioda_pe) isn't released and
it dereferences the stale PCI bus that has been released. It leads
to kernel crash when referring to the stale PCI bus.

This fixes the issue by correcting the PE's primary bus when it's
oneline at plugging time, in pnv_pci_dma_bus_setup() which is to
be called by pcibios_fixup_bus().

Cc: stable@vger.kernel.org # v4.1+
Reported-by: default avatarAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Reported-by: default avatarPradipta Ghosh <pradghos@in.ibm.com>
Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: default avatarAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      1bc74f1c
    • Gavin Shan's avatar
      powerpc/eeh: Fix stale cached primary bus · 05ba75f8
      Gavin Shan authored 
      When PE is created, its primary bus is cached to pe->bus. At later
point, the cached primary bus is returned from eeh_pe_bus_get().
However, we could get stale cached primary bus and run into kernel
crash in one case: full hotplug as part of fenced PHB error recovery
releases all PCI busses under the PHB at unplugging time and recreate
them at plugging time. pe->bus is still dereferencing the PCI bus
that was released.

This adds another PE flag (EEH_PE_PRI_BUS) to represent the validity
of pe->bus. pe->bus is updated when its first child EEH device is
online and the flag is set. Before unplugging in full hotplug for
error recovery, the flag is cleared.

Fixes: 8cdb2833 ("powerpc/eeh: Trace PCI bus from PE")
Cc: stable@vger.kernel.org #v3.11+
Reported-by: default avatarAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Reported-by: default avatarPradipta Ghosh <pradghos@in.ibm.com>
Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: default avatarAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      05ba75f8
    • Denis Kirjanov's avatar
      powerpc/pseries: Don't trace hcalls on offline CPUs · 126df08c
      Denis Kirjanov authored 
      If a cpu is hotplugged while the hcall trace points are active, it's
possible to hit a warning from RCU due to the trace points calling into
RCU from an offline cpu, eg:

  RCU used illegally from offline CPU!
  rcu_scheduler_active = 1, debug_locks = 1

Make the hypervisor tracepoints conditional by using
TRACE_EVENT_FN_COND.
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarDenis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      126df08c
  13. 08 Feb, 2016 1 commit
    • Andreas Schwab's avatar
      powerpc: Fix dedotify for binutils >= 2.26 · f15838e9
      Andreas Schwab authored 
      Since binutils 2.26 BFD is doing suffix merging on STRTAB sections.  But
dedotify modifies the symbol names in place, which can also modify
unrelated symbols with a name that matches a suffix of a dotted name.  To
remove the leading dot of a symbol name we can just increment the pointer
into the STRTAB section instead.

Backport to all stables to avoid breakage when people update their
binutils - mpe.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarAndreas Schwab <schwab@linux-m68k.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      f15838e9
  15. 31 Jan, 2016 1 commit
    • Aneesh Kumar K.V's avatar
      powerpc/book3s_32: Fix build error with checkpoint restart · 19f97c98
      Aneesh Kumar K.V authored 
      In file included from mm/vmscan.c:54:0:
include/linux/swapops.h: In function ‘pte_to_swp_entry’:
include/linux/swapops.h:69:2: error: implicit declaration of function ‘pte_swp_soft_dirty’ [-Werror=implicit-function-declaration]
  if (pte_swp_soft_dirty(pte))
  ^
include/linux/swapops.h:70:3: error: implicit declaration of function ‘pte_swp_clear_soft_dirty’ [-Werror=implicit-function-declaration]
   pte = pte_swp_clear_soft_dirty(pte);

We support soft dirty tracking only with book3s 64 for now.
So change the Kconfig dependency accordingly. Also CHECKPOINT_RESTORE
feature is not really dependent on SOFT_DIRTY. We track the dependency
between MEM_SOFT_DIRTY and ARCH_SOFT_DIRTY through headers

Fixes: 7207f436 ("powerpc/mm: Add page soft dirty tracking")
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      19f97c98
  17. 28 Jan, 2016 2 commits
    • Aneesh Kumar K.V's avatar
      powerpc/mm: Fixup _HPAGE_CHG_MASK · 2d19fc63
      Aneesh Kumar K.V authored 
      This was wrongly updated by commit 7aa9a23c ("powerpc, thp: remove
infrastructure for handling splitting PMDs") during the last merge
window. Fix it up.

This could lead to incorrect behaviour in THP and/or mprotect(), at a
minimum.

Fixes: 7aa9a23c ("powerpc, thp: remove infrastructure for handling splitting PMDs")
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      2d19fc63
    • Madhavan Srinivasan's avatar
      powerpc/perf: Remove PPMU_HAS_SSLOT flag for Power8 · 370f06c8
      Madhavan Srinivasan authored 
      Commit 7a786832 ("powerpc/perf: Add an explict flag indicating
presence of SLOT field") introduced the PPMU_HAS_SSLOT flag to remove
the assumption that MMCRA[SLOT] was present when PPMU_ALT_SIPR was not
set.

That commit's changelog also mentions that Power8 does not support
MMCRA[SLOT]. However when the Power8 PMU support was merged, it
errnoeously included the PPMU_HAS_SSLOT flag.

So remove PPMU_HAS_SSLOT from the Power8 flags.

mpe: On systems where MMCRA[SLOT] exists, the field occupies bits 37:39
(IBM numbering). On Power8 bit 37 is reserved, and 38:39 overlap with
the high bits of the Threshold Event Counter Mantissa. I am not aware of
any published events which use the threshold counting mechanism, which
would cause the mantissa bits to be set. So in practice this bug is
unlikely to trigger.

Fixes: e05b9b9e ("powerpc/perf: Power8 PMU support")
Signed-off-by: default avatarMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      370f06c8
  19. 27 Jan, 2016 1 commit
  21. 25 Jan, 2016 1 commit
  23. 21 Jan, 2016 3 commits
    • Stephen Rothwell's avatar
      powerpc: Remove newly added extra definition of pmd_dirty · 0e2bce74
      Stephen Rothwell authored 
      Commit d5d6a443 ("arch/powerpc/include/asm/pgtable-ppc64.h:
add pmd_[dirty|mkclean] for THP") added a new identical definition
of pmd_dirty(). Remove it again.

Cc: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      0e2bce74
    • Alan Modra's avatar
      powerpc: Simplify module TOC handling · c153693d
      Alan Modra authored 
      PowerPC64 uses the symbol .TOC. much as other targets use
_GLOBAL_OFFSET_TABLE_. It identifies the value of the GOT pointer (or in
powerpc parlance, the TOC pointer). Global offset tables are generally
local to an executable or shared library, or in the kernel, module. Thus
it does not make sense for a module to resolve a relocation against
.TOC. to the kernel's .TOC. value. A module has its own .TOC., and
indeed the powerpc64 module relocation processing ignores the kernel
value of .TOC. and instead calculates a module-local value.

This patch removes code involved in exporting the kernel .TOC., tweaks
modpost to ignore an undefined .TOC., and the module loader to twiddle
the section symbol so that .TOC. isn't seen as undefined.

Note that if the kernel was compiled with -msingle-pic-base then ELFv2
would not have function global entry code setting up r2. In that case
the module call stubs would need to be modified to set up r2 using the
kernel .TOC. value, requiring some of this code to be reinstated.

mpe: Furthermore a change in binutils master (not yet released) causes
the current way we handle the TOC to no longer work when building with
MODVERSIONS=y and RELOCATABLE=n. The symptom is that modules can not be
loaded due to there being no version found for TOC.

Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: default avatarAlan Modra <amodra@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      c153693d
    • Chandan Rajendra's avatar
      powerpc: Wire up copy_file_range() syscall · d7f9ee60
      Chandan Rajendra authored 
      Test runs on a ppc64 BE guest succeeded using modified fstests.

Also tested on ppc64 LE using a home made test - mpe.
Signed-off-by: default avatarChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      d7f9ee60
  25. 20 Jan, 2016 21 commits
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