linux-stable.git/arch/powerpc, branch v3.19.2

cxl: Fix device_node reference counting

2015-03-18T13:11:12+00:00

commit 6f963ec2d6bf2476a16799eece920acb2100ff1c upstream.

When unbinding and rebinding the driver on a system with a card in PHB0, this
error condition is reached after a few attempts:

ERROR: Bad of_node_put() on /pciex@3fffe40000000
CPU: 0 PID: 3040 Comm: bash Not tainted 3.18.0-rc3-12545-g3627ffe #152
Call Trace:
[c000000721acb5c0] [c00000000086ef94] .dump_stack+0x84/0xb0 (unreliable)
[c000000721acb640] [c00000000073a0a8] .of_node_release+0xd8/0xe0
[c000000721acb6d0] [c00000000044bc44] .kobject_release+0x74/0xe0
[c000000721acb760] [c0000000007394fc] .of_node_put+0x1c/0x30
[c000000721acb7d0] [c000000000545cd8] .cxl_probe+0x1a98/0x1d50
[c000000721acb900] [c0000000004845a0] .local_pci_probe+0x40/0xc0
[c000000721acb980] [c000000000484998] .pci_device_probe+0x128/0x170
[c000000721acba30] [c00000000052400c] .driver_probe_device+0xac/0x2a0
[c000000721acbad0] [c000000000522468] .bind_store+0x108/0x160
[c000000721acbb70] [c000000000521448] .drv_attr_store+0x38/0x60
[c000000721acbbe0] [c000000000293840] .sysfs_kf_write+0x60/0xa0
[c000000721acbc50] [c000000000292500] .kernfs_fop_write+0x140/0x1d0
[c000000721acbcf0] [c000000000208648] .vfs_write+0xd8/0x260
[c000000721acbd90] [c000000000208b18] .SyS_write+0x58/0x100
[c000000721acbe30] [c000000000009258] syscall_exit+0x0/0x98

We are missing a call to of_node_get(). pnv_pci_to_phb_node() should
call of_node_get() otherwise np's reference count isn't incremented and
it might go away. Rename pnv_pci_to_phb_node() to pnv_pci_get_phb_node()
so it's clear it calls of_node_get().

Signed-off-by: Ryan Grimm 
Acked-by: Ian Munsie 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

ppc/kvm: Replace ACCESS_ONCE with READ_ONCE

2015-03-06T22:57:43+00:00

commit 5ee07612e9e20817bb99256ab6cf1400fd5aa270 upstream.

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the ppc/kvm code to replace ACCESS_ONCE with READ_ONCE.

Signed-off-by: Christian Borntraeger 
Acked-by: Alexander Graf 
Signed-off-by: Greg Kroah-Hartman

ppc/hugetlbfs: Replace ACCESS_ONCE with READ_ONCE

2015-03-06T22:57:43+00:00

commit da1a288d8562739aa8ba0273d4fb6b73b856c0d3 upstream.

ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)

Change the ppc/hugetlbfs code to replace ACCESS_ONCE with READ_ONCE.

Signed-off-by: Christian Borntraeger 
Signed-off-by: Greg Kroah-Hartman

axonram: Fix bug in direct_access

2015-03-06T22:57:32+00:00

commit 91117a20245b59f70b563523edbf998a62fc6383 upstream.

The 'pfn' returned by axonram was completely bogus, and has been since
2008.

Signed-off-by: Matthew Wilcox 
Reviewed-by: Jan Kara 
Reviewed-by: Mathieu Desnoyers 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

mm/debug_pagealloc: fix build failure on ppc and some other archs

2015-02-05T21:35:30+00:00

Kim Phillips reported following build failure.

  LD      init/built-in.o
  mm/built-in.o: In function `free_pages_prepare':
  mm/page_alloc.c:770: undefined reference to `.kernel_map_pages'
  mm/built-in.o: In function `prep_new_page':
  mm/page_alloc.c:933: undefined reference to `.kernel_map_pages'
  mm/built-in.o: In function `map_pages':
  mm/compaction.c:61: undefined reference to `.kernel_map_pages'
  make: *** [vmlinux] Error 1

Reason for this problem is that commit 031bc5743f15
("mm/debug-pagealloc: make debug-pagealloc boottime configurable")
forgot to remove the old declaration of kernel_map_pages() for some
architectures.  This patch removes them to fix build failure.

Reported-by: Kim Phillips 
Signed-off-by: Joonsoo Kim 
Cc: Heiko Carstens 
Cc: Martin Schwidefsky 
Cc: David Miller 
Cc: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vm: add VM_FAULT_SIGSEGV handling support

2015-01-29T18:51:32+00:00

The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d4514 ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.

Reported-and-tested-by: Takashi Iwai 
Tested-by: Jan Engelhardt 
Acked-by: Heiko Carstens  # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds

Merge tag 'powerpc-3.19-5' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

2015-01-27T18:04:38+00:00

Pull powerpc fixes from Michael Ellerman:
 "Two powerpc fixes"

* tag 'powerpc-3.19-5' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
  powerpc/powernv: Restore LPCR with LPCR_PECE1 cleared
  powerpc/xmon: Fix another endiannes issue in RTAS call from xmon

Merge tag 'pci-v3.19-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

2015-01-23T22:58:47+00:00

Pull PCI fixes from Bjorn Helgaas:
 "These are fixes for:

   - a resource management problem that causes a Radeon "Fatal error
     during GPU init" on machines where the BIOS programmed an invalid
     Root Port window.  This was a regression in v3.16.

   - an Atheros AR93xx device that doesn't handle PCI bus resets
     correctly.  This was a regression in v3.14.

   - an out-of-date email address"

* tag 'pci-v3.19-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  MAINTAINERS: Update Richard Zhu's email address
  sparc/PCI: Clip bridge windows to fit in upstream windows
  powerpc/PCI: Clip bridge windows to fit in upstream windows
  parisc/PCI: Clip bridge windows to fit in upstream windows
  mn10300/PCI: Clip bridge windows to fit in upstream windows
  microblaze/PCI: Clip bridge windows to fit in upstream windows
  ia64/PCI: Clip bridge windows to fit in upstream windows
  frv/PCI: Clip bridge windows to fit in upstream windows
  alpha/PCI: Clip bridge windows to fit in upstream windows
  x86/PCI: Clip bridge windows to fit in upstream windows
  PCI: Add pci_claim_bridge_resource() to clip window if necessary
  PCI: Add pci_bus_clip_resource() to clip to fit upstream window
  PCI: Pass bridge device, not bus, when updating bridge windows
  PCI: Mark Atheros AR93xx to avoid bus reset
  PCI: Add flag for devices where we can't use bus reset

Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2015-01-22T18:40:36+00:00

Pull module and param fixes from Rusty Russell:
 "Surprising number of fixes this merge window :(

  The first two are minor fallout from the param rework which went in
  this merge window.

  The next three are a series which fixes a longstanding (but never
  previously reported and unlikely , so no CC stable) race between
  kallsyms and freeing the init section.

  Finally, a minor cleanup as our module refcount will now be -1 during
  unload"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  module: make module_refcount() a signed integer.
  module: fix race in kallsyms resolution during module load success.
  module: remove mod arg from module_free, rename module_memfree().
  module_arch_freeing_init(): new hook for archs before module->module_init freed.
  param: fix uninitialized read with CONFIG_DEBUG_LOCK_ALLOC
  param: initialize store function to NULL if not available.

powerpc/powernv: Restore LPCR with LPCR_PECE1 cleared

2015-01-22T06:22:57+00:00

LPCR_PECE1 bit controls whether decrementer interrupts are allowed to
cause exit from power-saving mode. While waking up from winkle, restoring
LPCR with LPCR_PECE1 set (i.e Decrementer interrupts allowed) can cause
issue in the following scenario:

- All the threads in a core are offlined. The core enters deep winkle.
- Spurious interrupt wakes up a thread in the core. Here LPCR is restored
  with LPCR_PECE1 bit set.
- Since it was a spurious interrupt on a offline thread, the thread clears
  the interrupt and goes back to winkle.
- Here before the thread executes winkle and puts the core into deep winkle,
  if a decrementer interrupt occurs on any of the sibling threads in the core
  that thread wakes up.
- Since in offline loop we are flushing interrupt only in case of external
  interrupt, the decrementer interrupt does not get flushed. So at this stage
  the thread is stuck in this is loop of waking up at 0x100 due to decrementer
  interrupt, not flushing the interrupt as only external interrupts get flushed,
  entering winkle, waking up at 0x100 again.

Fix this by programming PORE to restore LPCR with LPCR_PECE1 bit
cleared when waking up from winkle.

Signed-off-by: Shreyas B. Prabhu 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Signed-off-by: Michael Ellerman