Commit Graph

468206 Commits

Author SHA1 Message Date
Aneesh Kumar K.V
9e813308a5 powerpc/thp: Add tracepoints to track hugepage invalidate
Add tracepoint to track hugepage invalidate. This help us
in debugging difficult to track bugs.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:42 +10:00
Aneesh Kumar K.V
85c1fafd72 powerpc/mm: Use read barrier when creating real_pte
On ppc64 we support 4K hash pte with 64K page size. That requires
us to track the hash pte slot information on a per 4k basis. We do that
by storing the slot details in the second half of pte page. The pte bit
_PAGE_COMBO is used to indicate whether the second half need to be
looked while building real_pte. We need to use read memory barrier while
doing that so that load of hidx is not reordered w.r.t _PAGE_COMBO
check. On the store side we already do a lwsync in __hash_page_4K

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:41 +10:00
Aneesh Kumar K.V
7e467245bf powerpc/thp: Use ACCESS_ONCE when loading pmdp
We would get wrong results in compiler recomputed old_pmd. Avoid
that by using ACCESS_ONCE

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:41 +10:00
Aneesh Kumar K.V
969b7b208f powerpc/thp: Invalidate with vpn in loop
As per ISA, for 4k base page size we compare 14..65 bits of VA specified
with the entry_VA in tlb. That implies we need to make sure we do a
tlbie with all the possible 4k va we used to access the 16MB hugepage.
With 64k base page size we compare 14..57 bits of VA. Hence we cannot
ignore the lower 24 bits of va while tlbie .We also cannot tlb
invalidate a 16MB entry with just one tlbie instruction because
we don't track which va was used to instantiate the tlb entry.

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:40 +10:00
Aneesh Kumar K.V
fc04795575 powerpc/thp: Handle combo pages in invalidate
If we changed base page size of the segment, either via sub_page_protect
or via remap_4k_pfn, we do a demote_segment which doesn't flush the hash
table entries. We do a lazy hash page table flush for all mapped pages
in the demoted segment. This happens when we handle hash page fault for
these pages.

We use _PAGE_COMBO bit along with _PAGE_HASHPTE to indicate whether a
pte is backed by 4K hash pte. If we find _PAGE_COMBO not set on the pte,
that implies that we could possibly have older 64K hash pte entries in
the hash page table and we need to invalidate those entries.

Use _PAGE_COMBO to determine the page size with which we should
invalidate the hash table entries on unmap.

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:39 +10:00
Aneesh Kumar K.V
629149fae4 powerpc/thp: Invalidate old 64K based hash page mapping before insert of 4k pte
If we changed base page size of the segment, either via sub_page_protect
or via remap_4k_pfn, we do a demote_segment which doesn't flush the hash
table entries. We do a lazy hash page table flush for all mapped pages
in the demoted segment. This happens when we handle hash page fault
for these pages.

We use _PAGE_COMBO bit along with _PAGE_HASHPTE to indicate whether a
pte is backed by 4K hash pte. If we find _PAGE_COMBO not set on the pte,
that implies that we could possibly have older 64K hash pte entries in
the hash page table and we need to invalidate those entries.

Handle this correctly for 16M pages

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:39 +10:00
Aneesh Kumar K.V
fa1f8ae80f powerpc/thp: Don't recompute vsid and ssize in loop on invalidate
The segment identifier and segment size will remain the same in
the loop, So we can compute it outside. We also change the
hugepage_invalidate interface so that we can use it the later patch

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:38 +10:00
Aneesh Kumar K.V
b0aa44a3df powerpc/thp: Add write barrier after updating the valid bit
With hugepages, we store the hpte valid information in the pte page
whose address is stored in the second half of the PMD. Use a
write barrier to make sure clearing pmd busy bit and updating
hpte valid info are ordered properly.

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:37 +10:00
Nishanth Aravamudan
2fabf084b6 powerpc: reorder per-cpu NUMA information's initialization
There is an issue currently where NUMA information is used on powerpc
(and possibly ia64) before it has been read from the device-tree, which
leads to large slab consumption with CONFIG_SLUB and memoryless nodes.

NUMA powerpc non-boot CPU's cpu_to_node/cpu_to_mem is only accurate
after start_secondary(), similar to ia64, which is invoked via
smp_init().

Commit 6ee0578b4d ("workqueue: mark init_workqueues() as
early_initcall()") made init_workqueues() be invoked via
do_pre_smp_initcalls(), which is obviously before the secondary
processors are online.

Additionally, the following commits changed init_workqueues() to use
cpu_to_node to determine the node to use for kthread_create_on_node:

bce903809a ("workqueue: add wq_numa_tbl_len and
wq_numa_possible_cpumask[]")
f3f90ad469 ("workqueue: determine NUMA node of workers accourding to
the allowed cpumask")

Therefore, when init_workqueues() runs, it sees all CPUs as being on
Node 0. On LPARs or KVM guests where Node 0 is memoryless, this leads to
a high number of slab deactivations
(http://www.spinics.net/lists/linux-mm/msg67489.html).

Fix this by initializing the powerpc-specific CPU<->node/local memory
node mapping as early as possible, which on powerpc is
do_init_bootmem(). Currently that function initializes the mapping for
the boot CPU, but we extend it to setup the mapping for all possible
CPUs. Then, in smp_prepare_cpus(), we can correspondingly set the
per-cpu values for all possible CPUs. That ensures that before the
early_initcalls run (and really as early as possible), the per-cpu NUMA
mapping is accurate.

While testing memoryless nodes on PowerKVM guests with a fix to the
workqueue logic to use cpu_to_mem() instead of cpu_to_node(), with a
guest topology of:

available: 2 nodes (0-1)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
node 0 size: 0 MB
node 0 free: 0 MB
node 1 cpus: 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
node 1 size: 16336 MB
node 1 free: 15329 MB
node distances:
node   0   1
  0:  10  40
  1:  40  10

the slab consumption decreases from

Slab:             932416 kB
SUnreclaim:       902336 kB

to

Slab:             395264 kB
SUnreclaim:       359424 kB

And we a corresponding increase in the slab efficiency from

slab                                   mem     objs    slabs
                                      used   active   active
------------------------------------------------------------
kmalloc-16384                       337 MB   11.28%  100.00%
task_struct                         288 MB    9.93%  100.00%

to

slab                                   mem     objs    slabs
                                      used   active   active
------------------------------------------------------------
kmalloc-16384                        37 MB  100.00%  100.00%
task_struct                          31 MB  100.00%  100.00%

Powerpc didn't support memoryless nodes until recently (64bb80d87f
"powerpc/numa: Enable CONFIG_HAVE_MEMORYLESS_NODES" and 8c27226119
"powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID"). Those commits also
helped improve memory consumption with these kind of environments.

Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:14:05 +10:00
Himangi Saraogi
d658972284 powerpc/perf/hv-24x7: Use kmem_cache_free
Free memory allocated using kmem_cache_zalloc using kmem_cache_free
rather than kfree.

The Coccinelle semantic patch that makes this change is as follows:

// <smpl>
@@
expression x,E,c;
@@

 x = \(kmem_cache_alloc\|kmem_cache_zalloc\|kmem_cache_alloc_node\)(c,...)
 ... when != x = E
     when != &x
?-kfree(x)
+kmem_cache_free(c,x)
// </smpl>

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:14:04 +10:00
Thomas Falcon
587870e865 powerpc/pseries/hvcserver: Fix endian issue in hvcs_get_partner_info
A buffer returned by H_VTERM_PARTNER_INFO contains device information
in big endian format, causing problems for little endian architectures.
This patch ensures that they are in cpu endian.

Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:14:04 +10:00
Anton Blanchard
a71d64b4dc powerpc: Hard disable interrupts in xmon
xmon only soft disables interrupts. This seems like a bad idea - we
certainly don't want decrementer and PMU exceptions going off when
we are debugging something inside xmon.

This issue was uncovered when the hard lockup detector went off
inside xmon. To ensure we wont get a spurious hard lockup warning,
I also call touch_nmi_watchdog() when exiting xmon.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:48 +10:00
Nishanth Aravamudan
56758e3c3c powerpc: remove duplicate definition of TEXASR_FS
It appears that commits 7f06f21d40 ("powerpc/tm: Add checking to
treclaim/trechkpt") and e4e3812150 ("KVM: PPC: Book3S HV: Add
transactional memory support") both added definitions of TEXASR_FS.
Remove one of them. At the same time, fix the alignment of the remaining
definition (should be tab-separated like the rest of the #defines).

Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:47 +10:00
Gavin Shan
5efbabe09d powerpc/pseries: Avoid deadlock on removing ddw
Function remove_ddw() could be called in of_reconfig_notifier and
we potentially remove the dynamic DMA window property, which invokes
of_reconfig_notifier again. Eventually, it leads to the deadlock as
following backtrace shows.

The patch fixes the above issue by deferring releasing the dynamic
DMA window property while releasing the device node.

=============================================
[ INFO: possible recursive locking detected ]
3.16.0+ #428 Tainted: G        W
---------------------------------------------
drmgr/2273 is trying to acquire lock:
 ((of_reconfig_chain).rwsem){.+.+..}, at: [<c000000000091890>] \
 .__blocking_notifier_call_chain+0x40/0x78

but task is already holding lock:
 ((of_reconfig_chain).rwsem){.+.+..}, at: [<c000000000091890>] \
 .__blocking_notifier_call_chain+0x40/0x78

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock((of_reconfig_chain).rwsem);
  lock((of_reconfig_chain).rwsem);
 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by drmgr/2273:
 #0:  (sb_writers#4){.+.+.+}, at: [<c0000000001cbe70>] \
      .vfs_write+0xb0/0x1f8
 #1:  ((of_reconfig_chain).rwsem){.+.+..}, at: [<c000000000091890>] \
      .__blocking_notifier_call_chain+0x40/0x78

stack backtrace:
CPU: 17 PID: 2273 Comm: drmgr Tainted: G        W     3.16.0+ #428
Call Trace:
[c0000000137e7000] [c000000000013d9c] .show_stack+0x88/0x148 (unreliable)
[c0000000137e70b0] [c00000000083cd34] .dump_stack+0x7c/0x9c
[c0000000137e7130] [c0000000000b8afc] .__lock_acquire+0x128c/0x1c68
[c0000000137e7280] [c0000000000b9a4c] .lock_acquire+0xe8/0x104
[c0000000137e7350] [c00000000083588c] .down_read+0x4c/0x90
[c0000000137e73e0] [c000000000091890] .__blocking_notifier_call_chain+0x40/0x78
[c0000000137e7490] [c000000000091900] .blocking_notifier_call_chain+0x38/0x48
[c0000000137e7520] [c000000000682a28] .of_reconfig_notify+0x34/0x5c
[c0000000137e75b0] [c000000000682a9c] .of_property_notify+0x4c/0x54
[c0000000137e7650] [c000000000682bf0] .of_remove_property+0x30/0xd4
[c0000000137e76f0] [c000000000052a44] .remove_ddw+0x144/0x168
[c0000000137e7790] [c000000000053204] .iommu_reconfig_notifier+0x30/0xe0
[c0000000137e7820] [c00000000009137c] .notifier_call_chain+0x6c/0xb4
[c0000000137e78c0] [c0000000000918ac] .__blocking_notifier_call_chain+0x5c/0x78
[c0000000137e7970] [c000000000091900] .blocking_notifier_call_chain+0x38/0x48
[c0000000137e7a00] [c000000000682a28] .of_reconfig_notify+0x34/0x5c
[c0000000137e7a90] [c000000000682e14] .of_detach_node+0x44/0x1fc
[c0000000137e7b40] [c0000000000518e4] .ofdt_write+0x3ac/0x688
[c0000000137e7c20] [c000000000238430] .proc_reg_write+0xb8/0xd4
[c0000000137e7cd0] [c0000000001cbeac] .vfs_write+0xec/0x1f8
[c0000000137e7d70] [c0000000001cc3b0] .SyS_write+0x58/0xa0
[c0000000137e7e30] [c00000000000a064] syscall_exit+0x0/0x98

Cc: stable@vger.kernel.org
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:47 +10:00
Gavin Shan
f1b3929c23 powerpc/pseries: Failure on removing device node
While running command "drmgr -c phb -r -s 'PHB 528'", following
backtrace jumped out because the target device node isn't marked
with OF_DETACHED by of_detach_node(), which caused by error
returned from memory hotplug related reconfig notifier when
disabling CONFIG_MEMORY_HOTREMOVE. The patch fixes it.

ERROR: Bad of_node_put() on /pci@800000020000210/ethernet@0
CPU: 14 PID: 2252 Comm: drmgr Tainted: G        W     3.16.0+ #427
Call Trace:
[c000000012a776a0] [c000000000013d9c] .show_stack+0x88/0x148 (unreliable)
[c000000012a77750] [c00000000083cd34] .dump_stack+0x7c/0x9c
[c000000012a777d0] [c0000000006807c4] .of_node_release+0x58/0xe0
[c000000012a77860] [c00000000038a7d0] .kobject_release+0x174/0x1b8
[c000000012a77900] [c00000000038a884] .kobject_put+0x70/0x78
[c000000012a77980] [c000000000681680] .of_node_put+0x28/0x34
[c000000012a77a00] [c000000000681ea8] .__of_get_next_child+0x64/0x70
[c000000012a77a90] [c000000000682138] .of_find_node_by_path+0x1b8/0x20c
[c000000012a77b40] [c000000000051840] .ofdt_write+0x308/0x688
[c000000012a77c20] [c000000000238430] .proc_reg_write+0xb8/0xd4
[c000000012a77cd0] [c0000000001cbeac] .vfs_write+0xec/0x1f8
[c000000012a77d70] [c0000000001cc3b0] .SyS_write+0x58/0xa0
[c000000012a77e30] [c00000000000a064] syscall_exit+0x0/0x98

Cc: stable@vger.kernel.org
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:46 +10:00
Benjamin Herrenschmidt
ce8f150a17 powerpc/boot: Use correct zlib types for comparison
Avoids this warning:

arch/powerpc/boot/gunzip_util.c:118:9: warning: comparison of distinct pointer types lacks a cast

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:45 +10:00
Vasant Hegde
b09c2ec408 powerpc/powernv: Interface to register/unregister opal dump region
PowerNV platform is capable of capturing host memory region when system
crashes (because of host/firmware). We have new OPAL API to register/
unregister memory region to be captured when system crashes.

This patch adds support for new API. Also during boot time we register
kernel log buffer and unregister before doing kexec.

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:45 +10:00
Vasant Hegde
14c4000a88 printk: Add function to return log buffer address and size
Platforms like IBM Power Systems supports service processor
assisted dump. It provides interface to add memory region to
be captured when system is crashed.

During initialization/running we can add kernel memory region
to be collected.

Presently we don't have a way to get the log buffer base address
and size. This patch adds support to return log buffer address
and size.

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
2014-08-13 15:13:44 +10:00
Michael Ellerman
3609e09fd8 powerpc: Add POWER8 features to CPU_FTRS_POSSIBLE/ALWAYS
We have been a bit slack about updating the CPU_FTRS_POSSIBLE and
CPU_FTRS_ALWAYS masks. When we added POWER8, and also POWER8E we forgot
to update the ALWAYS mask. And when we added POWER8_DD1 we forgot to
update both the POSSIBLE and ALWAYS masks.

Luckily this hasn't caused any actual bugs AFAICS. Failing to update the
ALWAYS mask just forgoes a potential optimisation opportunity. Failing
to update the POSSIBLE mask for POWER8_DD1 is also OK because it only
removes a bit rather than adding any.

Regardless they should all be in both masks so as to avoid any future
bugs when the set of ALWAYS/POSSIBLE bits changes, or the masks
themselves change.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michael Neuling <mikey@neuling.org>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:43 +10:00
Alistair Popple
97b3be1e94 powerpc/ppc476: Disable BTAC
This patch disables the branch target address CAM which under specific
circumstances may cause the processor to skip execution of 1-4
instructions. This fixes IBM Erratum #47.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:42 +10:00
Gavin Shan
763fe0addb powerpc/powernv: Fix IOMMU group lost
When we take full hotplug to recover from EEH errors, PCI buses
could be involved. For the case, the child devices of involved
PCI buses can't be attached to IOMMU group properly, which is
caused by commit 3f28c5a ("powerpc/powernv: Reduce multi-hit of
iommu_add_device()").

When adding the PCI devices of the newly created PCI buses to
the system, the IOMMU group is expected to be added in (C).
(A) fails to bind the IOMMU group because bus->is_added is
false. (B) fails because the device doesn't have binding IOMMU
table yet. bus->is_added is set to true at end of (C) and
pdev->is_added is set to true at (D).

   pcibios_add_pci_devices()
      pci_scan_bridge()
         pci_scan_child_bus()
            pci_scan_slot()
               pci_scan_single_device()
                  pci_scan_device()
                  pci_device_add()
                     pcibios_add_device()           A: Ignore
                     device_add()                   B: Ignore
                  pcibios_fixup_bus()
                     pcibios_setup_bus_devices()
                        pcibios_setup_device()      C: Hit
      pcibios_finish_adding_to_bus()
         pci_bus_add_devices()
            pci_bus_add_device()                    D: Add device

If the parent PCI bus isn't involved in hotplug, the IOMMU
group is expected to be bound in (B). (A) should fail as the
sysfs entries aren't populated.

The patch fixes the issue by reverting commit 3f28c5a and remove
WARN_ON() in iommu_add_device() to allow calling the function
even the specified device already has associated IOMMU group.

Cc: <stable@vger.kernel.org>  # 3.16+
Reported-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:42 +10:00
Michael Ellerman
78e05b1421 powerpc: Add smp_mb()s to arch_spin_unlock_wait()
Similar to the previous commit which described why we need to add a
barrier to arch_spin_is_locked(), we have a similar problem with
spin_unlock_wait().

We need a barrier on entry to ensure any spinlock we have previously
taken is visibly locked prior to the load of lock->slock.

It's also not clear if spin_unlock_wait() is intended to have ACQUIRE
semantics. For now be conservative and add a barrier on exit to give it
ACQUIRE semantics.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:27 +10:00
Michael Ellerman
51d7d5205d powerpc: Add smp_mb() to arch_spin_is_locked()
The kernel defines the function spin_is_locked(), which can be used to
check if a spinlock is currently locked.

Using spin_is_locked() on a lock you don't hold is obviously racy. That
is, even though you may observe that the lock is unlocked, it may become
locked at any time.

There is (at least) one exception to that, which is if two locks are
used as a pair, and the holder of each checks the status of the other
before doing any update.

Assuming *A and *B are two locks, and *COUNTER is a shared non-atomic
value:

The first CPU does:

	spin_lock(*A)

	if spin_is_locked(*B)
		# nothing
	else
		smp_mb()
		LOAD r = *COUNTER
		r++
		STORE *COUNTER = r

	spin_unlock(*A)

And the second CPU does:

	spin_lock(*B)

	if spin_is_locked(*A)
		# nothing
	else
		smp_mb()
		LOAD r = *COUNTER
		r++
		STORE *COUNTER = r

	spin_unlock(*B)

Although this is a strange locking construct, it should work.

It seems to be understood, but not documented, that spin_is_locked() is
not a memory barrier, so in the examples above and below the caller
inserts its own memory barrier before acting on the result of
spin_is_locked().

For now we assume spin_is_locked() is implemented as below, and we break
it out in our examples:

	bool spin_is_locked(*LOCK) {
		LOAD l = *LOCK
		return l.locked
	}

Our intuition is that there should be no problem even if the two code
sequences run simultaneously such as:

	CPU 0			CPU 1
	==================================================
	spin_lock(*A)		spin_lock(*B)
	LOAD b = *B		LOAD a = *A
	if b.locked # true	if a.locked # true
	# nothing		# nothing
	spin_unlock(*A)		spin_unlock(*B)

If one CPU gets the lock before the other then it will do the update and
the other CPU will back off:

	CPU 0			CPU 1
	==================================================
	spin_lock(*A)
	LOAD b = *B
				spin_lock(*B)
	if b.locked # false	LOAD a = *A
	else			if a.locked # true
	smp_mb()		# nothing
	LOAD r1 = *COUNTER	spin_unlock(*B)
	r1++
	STORE *COUNTER = r1
	spin_unlock(*A)

However in reality spin_lock() itself is not indivisible. On powerpc we
implement it as a load-and-reserve and store-conditional.

Ignoring the retry logic for the lost reservation case, it boils down to:
	spin_lock(*LOCK) {
		LOAD l = *LOCK
		l.locked = true
		STORE *LOCK = l
		ACQUIRE_BARRIER
	}

The ACQUIRE_BARRIER is required to give spin_lock() ACQUIRE semantics as
defined in memory-barriers.txt:

     This acts as a one-way permeable barrier.  It guarantees that all
     memory operations after the ACQUIRE operation will appear to happen
     after the ACQUIRE operation with respect to the other components of
     the system.

On modern powerpc systems we use lwsync for ACQUIRE_BARRIER. lwsync is
also know as "lightweight sync", or "sync 1".

As described in Power ISA v2.07 section B.2.1.1, in this scenario the
lwsync is not the barrier itself. It instead causes the LOAD of *LOCK to
act as the barrier, preventing any loads or stores in the locked region
from occurring prior to the load of *LOCK.

Whether this behaviour is in accordance with the definition of ACQUIRE
semantics in memory-barriers.txt is open to discussion, we may switch to
a different barrier in future.

What this means in practice is that the following can occur:

	CPU 0			CPU 1
	==================================================
	LOAD a = *A 		LOAD b = *B
	a.locked = true		b.locked = true
	LOAD b = *B		LOAD a = *A
	STORE *A = a		STORE *B = b
	if b.locked # false	if a.locked # false
	else			else
	smp_mb()		smp_mb()
	LOAD r1 = *COUNTER	LOAD r2 = *COUNTER
	r1++			r2++
	STORE *COUNTER = r1
				STORE *COUNTER = r2	# Lost update
	spin_unlock(*A)		spin_unlock(*B)

That is, the load of *B can occur prior to the store that makes *A
visibly locked. And similarly for CPU 1. The result is both CPUs hold
their lock and believe the other lock is unlocked.

The easiest fix for this is to add a full memory barrier to the start of
spin_is_locked(), so adding to our previous definition would give us:

	bool spin_is_locked(*LOCK) {
		smp_mb()
		LOAD l = *LOCK
		return l.locked
	}

The new barrier orders the store to the lock we are locking vs the load
of the other lock:

	CPU 0			CPU 1
	==================================================
	LOAD a = *A 		LOAD b = *B
	a.locked = true		b.locked = true
	STORE *A = a		STORE *B = b
	smp_mb()		smp_mb()
	LOAD b = *B		LOAD a = *A
	if b.locked # true	if a.locked # true
	# nothing		# nothing
	spin_unlock(*A)		spin_unlock(*B)

Although the above example is theoretical, there is code similar to this
example in sem_lock() in ipc/sem.c. This commit in addition to the next
commit appears to be a fix for crashes we are seeing in that code where
we believe this race happens in practice.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:26 +10:00
Guenter Roeck
11d549048e powerpc: Fix "attempt to move .org backwards" error
Once again, we see

arch/powerpc/kernel/exceptions-64s.S: Assembler messages:
arch/powerpc/kernel/exceptions-64s.S:865: Error: attempt to move .org backwards
arch/powerpc/kernel/exceptions-64s.S:866: Error: attempt to move .org backwards
arch/powerpc/kernel/exceptions-64s.S:890: Error: attempt to move .org backwards

when compiling ppc:allmodconfig.

This time the problem has been caused by to commit 0869b6fd20
("powerpc/book3s: Add basic infrastructure to handle HMI in Linux"),
which adds functions hmi_exception_early and hmi_exception_after_realmode
into a critical (size-limited) code area, even though that does not appear
to be necessary.

Move those functions to a non-critical area of the file.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:25 +10:00
Scott Wood
5d61a2172a powerpc/nohash: Split __early_init_mmu() into boot and secondary
__early_init_mmu() does some things that are really only needed by the
boot cpu.  On FSL booke, This includes calling
memblock_enforce_memory_limit(), which is labelled __init.  Secondary
cpu init code can't be __init as that would break CPU hotplug.

While it's probably a bug that memblock_enforce_memory_limit() isn't
__init_memblock instead, there's no reason why we should be doing this
stuff for secondary cpus in the first place.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:25 +10:00
Mitesh Ahuja
96c51abecc RDMA/ocrdma: report asic-id in query device
Ocrdma does not report hw_ver when query_device is issued.  This patch
adds a meaningful value to this field.

Signed-off-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Mitesh Ahuja <mitesh.ahuja@emulex.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-08-12 22:07:47 -07:00
Devesh Sharma
8ac0c7c7a1 RDMA/ocrdma: Update sli data structure for endianness
Update the sli specific mailbox command request/response data
sturcures to fix endianness issues.

Signed-off-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-08-12 22:07:40 -07:00
Devesh Sharma
0ea8726250 RDMA/ocrdma: Obtain SL from device structure
Currently, driver obtains service level value from ah_attr->sl field.
However, this field is set to zero all the times from rdma-cm.  This
patch allows create_ah to obtain service level from dev->sl.

Signed-off-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-08-12 22:07:30 -07:00
Doug Ledford
db1044d458 RDMA/uapi: Include socket.h in rdma_user_cm.h
added struct sockaddr_storage to rdma_user_cm.h without also adding an
include for linux/socket.h to make sure it is defined.  Systemtap
needs the header files to build standalone and cannot rely on other
files to pre-include other headers, so add linux/socket.h to the list
of includes in this file.

Fixes: ee7aed4528 ("RDMA/ucma: Support querying for AF_IB addresses")
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-08-12 22:03:31 -07:00
Doug Ledford
2aa1cf64aa IB/srpt: Handle GID change events
GID change events need a refresh just like LID change events and several
others.  Handle this the same as the others.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-08-12 22:01:55 -07:00
Fabian Frederick
a8f731ebd1 IB/mlx5: Use ARRAY_SIZE instead of sizeof/sizeof[0]
Acked-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-08-12 22:00:58 -07:00
Fabian Frederick
a57f23f675 IB/mlx4: Use ARRAY_SIZE instead of sizeof/sizeof[0]
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-08-12 22:00:23 -07:00
Dan Carpenter
859976da03 RDMA/amso1100: Check for integer overflow in c2_alloc_cq_buf()
This is a static checker fix.  The static checker says that q_size comes
from the user and can be any 32 bit value.  The call tree is:
  --> ib_uverbs_create_cq()
      --> c2_create_cq()
          --> c2_init_cq()

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-08-12 22:00:03 -07:00
Fabian Frederick
e42fa2092c IPoIB: Remove unnecessary test for NULL before debugfs_remove()
Fix checkpatch warning:

    WARNING: debugfs_remove(NULL) is safe this check is probably not required

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-08-12 21:59:54 -07:00
Benoit Taine
9baa3c34ac PCI: Remove DEFINE_PCI_DEVICE_TABLE macro use
We should prefer `struct pci_device_id` over `DEFINE_PCI_DEVICE_TABLE` to
meet kernel coding style guidelines.  This issue was reported by checkpatch.

A simplified version of the semantic patch that makes this change is as
follows (http://coccinelle.lip6.fr/):

// <smpl>

@@
identifier i;
declarer name DEFINE_PCI_DEVICE_TABLE;
initializer z;
@@

- DEFINE_PCI_DEVICE_TABLE(i)
+ const struct pci_device_id i[]
= z;

// </smpl>

[bhelgaas: add semantic patch]
Signed-off-by: Benoit Taine <benoit.taine@lip6.fr>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-08-12 12:15:14 -06:00
Mark Brown
a6b48699ae Input: joystick - use get_cycles on ARMv8
As with ARM the ARMv8 architecture provides a cycle counter which can be
used to provide a high resolution time for the joystick driver and
silence the build warning that results from not having a precise timer
on ARMv8, making allmodconfig and allyesconfig quieter.

Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2014-08-12 09:59:40 -07:00
Geert Uytterhoeven
41a7458147 Input: wacom - fix compiler warning if !CONFIG_PM
If CONFIG_PM is not set:

drivers/hid/wacom_sys.c:1436: warning: ‘wacom_reset_resume’ defined but
not used

Protect the unused functions by #ifdef CONFIG_PM to fix this.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2014-08-12 09:59:29 -07:00
Jan Kara
01777836c8 reiserfs: Fix use after free in journal teardown
If do_journal_release() races with do_journal_end() which requeues
delayed works for transaction flushing, we can leave work items for
flushing outstanding transactions queued while freeing them. That
results in use after free and possible crash in run_timers_softirq().

Fix the problem by not requeueing works if superblock is being shut down
(MS_ACTIVE not set) and using cancel_delayed_work_sync() in
do_journal_release().

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
2014-08-12 12:46:30 +02:00
Jean Sacren
5e815d8418 e1000e: delete excessive space character in debug message
There is an excessive space character between the word and the
period in the debug message. So delete it.

Signed-off-by: Jean Sacren <sakiwit@gmail.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-08-12 01:16:19 -07:00
Jean Sacren
da8ed50b8b e1000e: fix trivial kernel doc typos
The macro E1000_success is meant to be E1000_SUCCESS. As the return
statement in the function is good as is, let's simply correct the
comment for this trivial matter.

Additionally E1000_ERR_HOST_INTERFACE_COMMAND is supposed to be
-E1000_ERR_HOST_INTERFACE_COMMAND.

Signed-off-by: Jean Sacren <sakiwit@gmail.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-08-12 01:07:21 -07:00
Rickard Strandqvist
35a7d80459 i40e: Cleaning up missing null-terminate in conjunction with strncpy
Replacing strncpy with strlcpy to avoid strings that lacks null terminate.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Tested-By: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-08-12 00:55:53 -07:00
Julia Lawall
f57e4fbdcc i40e: use correct structure type name in sizeof
Correct typo in the name of the type given to sizeof.  Because it is the
size of a pointer that is wanted, the typo has no impact on compilation or
execution.

This problem was found using Coccinelle (http://coccinelle.lip6.fr/).  The
semantic patch used can be found in message 0 of this patch series.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Tested-By: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-08-12 00:47:50 -07:00
Wei Yongjun
952d9639db i40e: fix sparse non static symbol warning
Fixes the following sparse warnings:

drivers/net/ethernet/intel/i40e/i40e_nvm.c:254:13: warning:
 symbol 'i40e_write_nvm_aq' was not declared. Should it be static?

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Tested-By: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-08-12 00:34:18 -07:00
Lucas Tanure
e222ade63f i40e: Fix missing uapi/linux/dcbnl.h include in i40e_fcoe.c
Fix missing include in Intel i40e driver. Without this include linux next
tree won't compile.

Signed-off-by: Lucas Tanure <tanure@linux.com>
Tested-by:  Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2014-08-11 23:59:32 -07:00
David S. Miller
8bccf5b313 sparc64: Fix pcr_ops initialization and usage bugs.
Christopher reports that perf_event_print_debug() can crash in uniprocessor
builds.  The crash is due to pcr_ops being NULL.

This happens because pcr_arch_init() is only invoked by smp_cpus_done() which
only executes in SMP builds.

init_hw_perf_events() is closely intertwined with pcr_ops being setup properly,
therefore:

1) Call pcr_arch_init() early on from init_hw_perf_events(), instead of
   from smp_cpus_done().

2) Do not hook up a PMU type if pcr_ops is NULL after pcr_arch_init().

3) Move init_hw_perf_events to a later initcall so that it we will be
   sure to invoke pcr_arch_init() after all cpus are brought up.

Finally, guard the one naked sequence of pcr_ops dereferences in
__global_pmu_self() with an appropriate NULL check.

Reported-by: Christopher Alexander Tobias Schulze <cat.schulze@alice-dsl.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-11 20:45:12 -07:00
David S. Miller
58556104e9 sparc64: Do not disable interrupts in nmi_cpu_busy()
nmi_cpu_busy() is a SMP function call that just makes sure that all of the
cpus are spinning using cpu cycles while the NMI test runs.

It does not need to disable IRQs because we just care about NMIs executing
which will even with 'normal' IRQs disabled.

It is not legal to enable hard IRQs in a SMP cross call, in fact this bug
triggers the BUG check in irq_work_run_list():

	BUG_ON(!irqs_disabled());

Because now irq_work_run() is invoked from the tail of
generic_smp_call_function_single_interrupt().

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-11 20:45:01 -07:00
David S. Miller
61dac43ee6 Merge branch 'bcmgenet'
Florian Fainelli says:

====================
net: bcmgenet: Wake-on-LAN and suspend fixes

This patch series fixes some mistakes that were introduced during the driver
changes adding support suspend/resume and Wake-on-LAN.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-11 15:10:17 -07:00
Florian Fainelli
98bb7399d2 net: bcmgenet: correctly resume adapter from Wake-on-LAN
In case we configured the adapter to be a wake up source from
Wake-on-LAN, but we never actually woke up using Wake-on-LAN, we will
leave the adapter in MagicPacket matching mode, which prevents any other
type of packets from reaching the RX engine. Fix this by calling
bcmgenet_power_up() with GENET_POWER_WOL_MAGIC to restore the adapter
configuration in bcmgenet_resume().

The second problem we had was an imbalanced clock disabling in
bcmgenet_wol_resume(), the Wake-on-LAN slow clock is only enabled in
bcmgenet_suspend() if we configured Wake-on-LAN, yet we unconditionally
disabled the clock in bcmgenet_wol_resume().

Fixes: 8c90db72f9 ("net: bcmgenet: suspend and resume from Wake-on-LAN")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-11 15:10:11 -07:00
Florian Fainelli
c677ba8b3c net: bcmgenet: update UMAC_CMD only when link is detected
When we bring the interface down, phy_stop() will schedule the PHY state
machine to call our link adjustment callback. By the time we do so, we
may have clock gated off the GENET hardware block, and this will cause
bus errors to happen in bcmgenet_mii_setup():

Make sure that we only touch the UMAC_CMD register when there is an
actual link. This is safe to do for two reasons:

- updating the Ethernet MAC registers only make sense when a physical
  link is present
- the PHY library state machine first set phydev->link = 0 before
  invoking phydev->adjust_link in the PHY_HALTED case

Fixes: 240524089d ("net: bcmgenet: only update UMAC_CMD if something changed")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-11 15:10:11 -07:00
Florian Fainelli
cc013fb488 net: bcmgenet: correctly suspend and resume PHY device
Make sure that we properly suspend and resume the PHY device when we
enter low power modes. We had two calls to bcmgenet_mii_reset() which
will issue a software-reset to the PHY without using the PHY library,
get rid of them since they are completely bogus and mess up with the PHY
library state. Make sure that we reset the PHY library cached values
(link, pause and duplex) to allow the link adjustment callback to be
invoked when needed.

Fixes: b6e978e504 ("net: bcmgenet: add suspend/resume callbacks")
Fixes: 1c1008c793 ("net: bcmgenet: add main driver file")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-11 15:10:11 -07:00