linux-stable.git/arch/powerpc, branch v4.2.1

KVM: PPC: Book3S HV: Fix race in reading change bit when removing HPTE

2015-09-21T17:10:55+00:00

commit 1e5bf454f58731e360e504253e85bae7aaa2d298 upstream.

The reference (R) and change (C) bits in a HPT entry can be set by
hardware at any time up until the HPTE is invalidated and the TLB
invalidation sequence has completed.  This means that when removing
a HPTE, we need to read the HPTE after the invalidation sequence has
completed in order to obtain reliable values of R and C.  The code
in kvmppc_do_h_remove() used to do this.  However, commit 6f22bd3265fb
("KVM: PPC: Book3S HV: Make HTAB code LE host aware") removed the
read after invalidation as a side effect of other changes.  This
restores the read of the HPTE after invalidation.

The user-visible effect of this bug would be that when migrating a
guest, there is a small probability that a page modified by the guest
and then unmapped by the guest might not get re-transmitted and thus
the destination might end up with a stale copy of the page.

Fixes: 6f22bd3265fb
Signed-off-by: Paul Mackerras 
Signed-off-by: Alexander Graf 
Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Exit on H_DOORBELL if HOST_IPI is set

2015-09-21T17:10:55+00:00

commit 06554d9f6cc8f0b5ec903db19726a15dfc7b09d6 upstream.

The code that handles the case when we receive a H_DOORBELL interrupt
has a comment which says "Hypervisor doorbell - exit only if host IPI
flag set".  However, the current code does not actually check if the
host IPI flag is set.  This is due to a comparison instruction that
got missed.

As a result, the current code performs the exit to host only
if some sibling thread or a sibling sub-core is exiting to the
host.  This implies that, an IPI sent to a sibling core in
(subcores-per-core != 1) mode will be missed by the host unless the
sibling core is on the exit path to the host.

This patch adds the missing comparison operation which will ensure
that when HOST_IPI flag is set, we unconditionally exit to the host.

Fixes: 66feed61cdf6
Signed-off-by: Gautham R. Shenoy 
Reviewed-by: David Gibson 
Signed-off-by: Paul Mackerras 
Signed-off-by: Greg Kroah-Hartman

powerpc/PCI: Disable MSI/MSI-X interrupts at PCI probe time in OF case

2015-08-26T11:40:50+00:00

Since commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if
kernel doesn't support MSI"), the setup of dev->msi_cap/msix_cap and the
disable of MSI/MSI-X interrupts isn't being done at PCI probe time, as
the logic responsible for this was moved in the aforementioned commit
from pci_device_add() to pci_setup_device(). The latter function is not
reachable on PowerPC pseries platform during Open Firmware PCI probing
time.

This exhibits as drivers not being able to enable MSI, eg:

  bnx2x 0000:01:00.0: no msix capability found

This patch calls pci_msi_setup_pci_dev() explicitly to disable MSI/MSI-X
during PCI probe time on pSeries platform.

Fixes: 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI")
[mpe: Flesh out change log and clarify comment]
Signed-off-by: Guilherme G. Piccoli 
Signed-off-by: Michael Ellerman

signal: fix information leak in copy_siginfo_from_user32

2015-08-07T01:39:40+00:00

This function can leak kernel stack data when the user siginfo_t has a
positive si_code value.  The top 16 bits of si_code descibe which fields
in the siginfo_t union are active, but they are treated inconsistently
between copy_siginfo_from_user32, copy_siginfo_to_user32 and
copy_siginfo_to_user.

copy_siginfo_from_user32 is called from rt_sigqueueinfo and
rt_tgsigqueueinfo in which the user has full control overthe top 16 bits
of si_code.

This fixes the following information leaks:
x86:   8 bytes leaked when sending a signal from a 32-bit process to
       itself. This leak grows to 16 bytes if the process uses x32.
       (si_code = __SI_CHLD)
x86:   100 bytes leaked when sending a signal from a 32-bit process to
       a 64-bit process. (si_code = -1)
sparc: 4 bytes leaked when sending a signal from a 32-bit process to a
       64-bit process. (si_code = any)

parsic and s390 have similar bugs, but they are not vulnerable because
rt_[tg]sigqueueinfo have checks that prevent sending a positive si_code
to a different process.  These bugs are also fixed for consistency.

Signed-off-by: Amanieu d'Antras 
Cc: Oleg Nesterov 
Cc: Ingo Molnar 
Cc: Russell King 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Chris Metcalf 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

powerpc/eeh-powernv: Fix unbalanced IRQ warning

2015-07-30T09:01:32+00:00

pnv_eeh_next_error() re-enables the eeh opal event interrupt but it
gets called from a loop if there are more outstanding events to
process, resulting in a warning due to enabling an already enabled
interrupt. Instead the interrupt should only be re-enabled once the
last outstanding event has been processed.

Tested-by: Daniel Axtens 
Reported-by: Daniel Axtens 
Signed-off-by: Alistair Popple 
Acked-by: Gavin Shan 
Signed-off-by: Michael Ellerman

powerpc/powernv/ioda2: Fix calculation for memory allocated for TCE table

2015-07-23T09:56:44+00:00

The existing code stores the amount of memory allocated for a TCE table.
At the moment it uses @offset which is a virtual offset in the TCE table
which is only correct for a one level tables and it does not include
memory allocated for intermediate levels. When multilevel TCE table is
requested, WARN_ON in tce_iommu_create_table() prints a warning.

This adds an additional counter to pnv_pci_ioda2_table_do_alloc_pages()
to count actually allocated memory.

Signed-off-by: Alexey Kardashevskiy 
Reviewed-by: David Gibson 
Signed-off-by: Michael Ellerman

powerpc/perf/24x7: Fix lockdep warning

2015-07-08T05:18:04+00:00

The sysfs attributes for the 24x7 counters are dynamically allocated.
Initialize the attributes using sysfs_attr_init() to fix following
warning which occurs when CONFIG_DEBUG_LOCK_VMALLOC=y.

[    0.346249] audit: initializing netlink subsys (disabled)
[    0.346284] audit: type=2000 audit(1436295254.340:1): initialized
[    0.346489] BUG: key c0000000efe90198 not in .data!
[    0.346491] DEBUG_LOCKS_WARN_ON(1)
[    0.346502] ------------[ cut here ]------------
[    0.346504] WARNING: at ../kernel/locking/lockdep.c:3002
[    0.346506] Modules linked in:

Reported-by: Gustavo Luiz Duarte 
Signed-off-by: Sukadev Bhattiprolu 
Tested-by: Gustavo Luiz Duarte 
Signed-off-by: Michael Ellerman

powerpc/powernv: Fix race in updating core_idle_state

2015-07-07T00:16:52+00:00

core_idle_state is maintained for each core. It uses 0-7 bits to track
whether a thread in the core has entered fastsleep or winkle. 8th bit is
used as a lock bit.
The lock bit is set in these 2 scenarios-
 - The thread is first in subcore to wakeup from sleep/winkle.
 - If its the last thread in the core about to enter sleep/winkle

While the lock bit is set, if any other thread in the core wakes up, it
loops until the lock bit is cleared before proceeding in the wakeup
path. This helps prevent race conditions w.r.t fastsleep workaround and
prevents threads from switching to process context before core/subcore
resources are restored.

But, in the path to sleep/winkle entry, we currently don't check for
lock-bit. This exposes us to following race when running with subcore
on-

First thread in the subcorea		Another thread in the same
waking up		   		core entering sleep/winkle

lwarx   r15,0,r14
ori     r15,r15,PNV_CORE_IDLE_LOCK_BIT
stwcx.  r15,0,r14
[Code to restore subcore state]

						lwarx   r15,0,r14
						[clear thread bit]
						stwcx.  r15,0,r14

andi.   r15,r15,PNV_CORE_IDLE_THREAD_BITS
stw     r15,0(r14)

Here, after the thread entering sleep clears its thread bit in
core_idle_state, the value is overwritten by the thread waking up.
In such cases when the core enters fastsleep, code mistakes an idle
thread as running. Because of this, the first thread waking up from
fastsleep which is supposed to resync timebase skips it. So we can
end up having a core with stale timebase value.

This patch fixes the above race by looping on the lock bit even while
entering the idle states.

Signed-off-by: Shreyas B. Prabhu 
Fixes: 7b54e9f213f76 'powernv/powerpc: Add winkle support for offline cpus'
Cc: stable@vger.kernel.org # 3.19+
Signed-off-by: Michael Ellerman

powerpc/powernv: Fix opal-elog interrupt handler

2015-07-06T10:24:36+00:00

The conversion of opal events to a proper irqchip means that handlers
are called until the relevant opal event has been cleared by
processing it. Events that queue work should therefore use a threaded
handler to mask the event until processing is complete.

Signed-off-by: Alistair Popple 
Tested-by: Aneesh Kumar K.V 
Signed-off-by: Michael Ellerman

powerpc/ppc4xx_hsta_msi: Include ppc-pci.h to fix reference to hose_list

2015-07-06T10:24:36+00:00

An earlier commit referenced 'hose_list' in sysdev/ppc4xx_hsta_msi.c.
hose_list is defined in ppc-pci.h, which was not included in that
file. Include it, fixing the build for the akebono defconfig used
by the kbuild test robot.

Fixes: f2c800aaceb6 ("powerpc/ppc4xx_hsta_msi: Move MSI-related ops to pci_controller_ops")
Reported-by: kbuild test robot 
Signed-off-by: Daniel Axtens 
Signed-off-by: Michael Ellerman