We have been observing hangs, both of KVM guest vcpu tasks and more
generally, where a process that is woken doesn't properly wake up and
continue to run, but instead sticks in TASK_WAKING state. This
happens because the update of rq->wake_list in ttwu_queue_remote()
is not ordered with the update of ipi_message in
smp_muxed_ipi_message_pass(), and the reading of rq->wake_list in
scheduler_ipi() is not ordered with the reading of ipi_message in
smp_ipi_demux(). Thus it is possible for the IPI receiver not to see
the updated rq->wake_list and therefore conclude that there is nothing
for it to do.
In order to make sure that anything done before smp_send_reschedule()
is ordered before anything done in the resulting call to scheduler_ipi(),
this adds barriers in smp_muxed_message_pass() and smp_ipi_demux().
The barrier in smp_muxed_message_pass() is a full barrier to ensure that
there is a full ordering between the smp_send_reschedule() caller and
scheduler_ipi(). In smp_ipi_demux(), we use xchg() rather than
xchg_local() because xchg() includes release and acquire barriers.
Using xchg() rather than xchg_local() makes sense given that
ipi_message is not just accessed locally.
This moves the barrier between setting the message and calling the
cause_ipi() function into the individual cause_ipi implementations.
Most of them -- those that used outb, out_8 or similar -- already had
a full barrier because out_8 etc. include a sync before the MMIO
store. This adds an explicit barrier in the two remaining cases.
These changes made no measurable difference to the speed of IPIs as
measured using a simple ping-pong latency test across two CPUs on
different cores of a POWER7 machine.
The analysis of the reason why processes were not waking up properly
is due to Milton Miller.
Cc: stable@vger.kernel.org # v3.0+
Reported-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
During a context switch we always restore the per thread DSCR value.
If we aren't doing explicit DSCR management
(ie thread.dscr_inherit == 0) and the default DSCR changed while
the process has been sleeping we end up with the wrong value.
Check thread.dscr_inherit and select the default DSCR or per thread
DSCR as required.
This was found with the following test case, when running with
more threads than CPUs (ie forcing context switching):
http://ozlabs.org/~anton/junkcode/dscr_default_test.c
With the four patches applied I can run a combination of all
test cases successfully at the same time:
http://ozlabs.org/~anton/junkcode/dscr_default_test.chttp://ozlabs.org/~anton/junkcode/dscr_explicit_test.chttp://ozlabs.org/~anton/junkcode/dscr_inherit_test.c
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> # 3.0+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
If the default DSCR is non zero we set thread.dscr_inherit in
copy_thread() meaning the new thread and all its children will ignore
future updates to the default DSCR. This is not intended and is
a change in behaviour that a number of our users have hit.
We just need to inherit thread.dscr and thread.dscr_inherit from
the parent which ends up being much simpler.
This was found with the following test case:
http://ozlabs.org/~anton/junkcode/dscr_default_test.c
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> # 3.0+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When we update the DSCR either via emulation of mtspr(DSCR) or via
a change to dscr_default in sysfs we don't update thread.dscr.
We will eventually update it at context switch time but there is
a period where thread.dscr is incorrect.
If we fork at this point we will copy the old value of thread.dscr
into the child. To avoid this, always keep thread.dscr in sync with
reality.
This issue was found with the following testcase:
http://ozlabs.org/~anton/junkcode/dscr_inherit_test.c
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> # 3.0+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Writing to dscr_default in sysfs doesn't actually change the DSCR -
we rely on a context switch on each CPU to do the work. There is no
guarantee we will get a context switch in a reasonable amount of time
so fire off an IPI to force an immediate change.
This issue was found with the following test case:
http://ozlabs.org/~anton/junkcode/dscr_explicit_test.c
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> # 3.0+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The CPU hotplug code for the powernv platform currently only puts
offline CPUs into nap mode if the powersave_nap variable is set.
However, HV-style KVM on this platform requires secondary CPU threads
to be offline and in nap mode. Since we know nap mode works just
fine on all POWER7 machines, and the only machines that support the
powernv platform are POWER7 machines, this changes the code to
always put offline CPUs into nap mode, regardless of powersave_nap.
Powersave_nap still controls whether or not CPUs go into nap mode
when idle, as before.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
At the moment the handler for hypervisor decrementer interrupts is
the same as for decrementer interrupts, i.e. timer_interrupt().
This is bogus; if we ever do get a hypervisor decrementer interrupt
it won't have anything to do with the next timer event. In fact
the only time we get hypervisor decrementer interrupts is when one
is left pending on exit from a KVM guest.
When we get a hypervisor decrementer interrupt we don't need to do
anything special to clear it, since they are edge-triggered on the
transition of HDEC from 0 to -1. Thus this adds an empty handler
function for them. We don't need to have them masked when interrupts
are soft-disabled, so we use STD_EXCEPTION_HV instead of
MASKABLE_EXCEPTION_HV.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch_update_cpu_topology() should only return 1 when the topology has
actually changed, and should return 0 otherwise.
This patch fixes a potential bug where rebuild_sched_domains() would
reinitialize the sched domains even when the topology hasn't changed.
Signed-off-by: Jesse Larrew <jlarrew@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch add ethtool supports for Supported and Advertised Pause Frame,
based on Adapter Flow Control settings.
Signed-off-by: Akeem G. Abodunrin <akeem.g.abodunrin@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
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Merge tag 'v3.6-rc4' into next
Linux 3.6-rc4
# gpg: Signature made Sat 01 Sep 2012 10:40:33 AM PDT using RSA key ID 00411886
# gpg: Good signature from "Linus Torvalds <torvalds@linux-foundation.org>"
Reduce skb truesize by 256 bytes.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Move the Tegra KBC platform data header out of arch/arm/mach-tegra, as
a pre-requisite of single zImage.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Early release of i210 devices had the loopback test of the ethtool
self-test disabled. This patch enables the loopback test for i210 devices.
Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Embedded.Hypervisor category defines GSPRG0..3 physical registers for guests.
Avoid SPRG4-7 usage as scratch in host exception handlers, otherwise guest
SPRG4-7 registers will be clobbered.
For bolted TLB miss exception handlers, which is the version currently
supported by KVM, use SPRN_SPRG_GEN_SCRATCH aka SPRG0 instead of
SPRN_SPRG_TLB_SCRATCH aka SPRG6. Keep using TLB PACA slots to fit in one
64-byte cache line.
For critical exception handlers use SPRG3 instead of SPRG7. Provide a routine
to store and restore user-visible SPRGs. This will be subsequently used
to restore VDSO information in SPRG3. Add EX_R13 to paca slots to free up
SPRG3 and change the critical exception epilog to use it.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Refactor exception prolog to get rid of mfspr srr1 duplicate. This was
introduced by KVM integration, with DO_KVM macro logic expecting srr1 value
earlier in r11.
Reserve r11 to hold srr1's value also required at the end of the prolog and
free up r10 to serve as spare in addition macros.
For syscalls case this change does not add any performance penalty. For irq
soft-disabled case the change adds a store/load of conditional register value
to/from a paca slot. Paca slots fit in one 64-byte cache line so these
additional operations have little impact on performance.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Hook DO_KVM macro into 64-bit booke for KVM integration. Extend interrupt
handlers' parameter list with interrupt vector numbers to accomodate the macro.
Only the bolted version of tlb miss handers is addressed now.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Guest Doorbell interrupts use guest save and restore registers. Add a new
Guest Doorbell exception type to accommodate GSRR0/1 SPRs usage in exception
prolog and fix the exception handler.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Machine check exception handler was using a wrong prolog. Hypervisors like
KVM which are called early from the exception handler rely on the interrupt
source.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This is the port of uprobes to powerpc. Usage is similar to x86.
[root@xxxx ~]# ./bin/perf probe -x /lib64/libc.so.6 malloc
Added new event:
probe_libc:malloc (on 0xb4860)
You can now use it in all perf tools, such as:
perf record -e probe_libc:malloc -aR sleep 1
[root@xxxx ~]# ./bin/perf record -e probe_libc:malloc -aR sleep 20
[ perf record: Woken up 22 times to write data ]
[ perf record: Captured and wrote 5.843 MB perf.data (~255302 samples) ]
[root@xxxx ~]# ./bin/perf report --stdio
...
69.05% tar libc-2.12.so [.] malloc
28.57% rm libc-2.12.so [.] malloc
1.32% avahi-daemon libc-2.12.so [.] malloc
0.58% bash libc-2.12.so [.] malloc
0.28% sshd libc-2.12.so [.] malloc
0.08% irqbalance libc-2.12.so [.] malloc
0.05% bzip2 libc-2.12.so [.] malloc
0.04% sleep libc-2.12.so [.] malloc
0.03% multipathd libc-2.12.so [.] malloc
0.01% sendmail libc-2.12.so [.] malloc
0.01% automount libc-2.12.so [.] malloc
The trap_nr addition patch is a prereq.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch adds support for resizing file systems with the meta_bg and
64bit features.
[ Added a fix by tytso to fix a divide by zero when resizing a
filesystem from 14 TB to 18TB. Also fixed overhead accounting for
meta_bg file systems.]
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Previously we allocated the s_group_info array with enough space for
any future possible growth of the file system via online resize. This
is unfortunate because it wastes memory, and it doesn't work for the
meta_bg scheme, since there is no limit based on the number of
reserved gdt blocks. So add the code to grow the s_group_info array
as needed.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Previously, we allocated the s_flex_groups array to the maximum size
that the file system could be resized. There was two problems with
this approach. First, it wasted memory in the common case where the
file system was not resized. Secondly, once we start allowing online
resizing using the meta_bg scheme, there is no maximum size that the
file system can be resized. So instead, we need to grow the
s_flex_groups at inline resize time.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The resize code was needlessly writing the backup block group
descriptor blocks multiple times (once per block group) during an
online resize.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
The resize code was copying blocks at the beginning of each block
group in order to copy the superblock and block group descriptor table
(gdt) blocks. This was, unfortunately, being done even for block
groups that did not have super blocks or gdt blocks. This is a
complete waste of perfectly good I/O bandwidth, to skip writing those
blocks for sparse bg's.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
Avoid changing o_blocks_count, since it is used later when reporting
old blocks count in debug mode.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
If the last group does not have enough space for group tables, ignore
it instead of calling BUG_ON().
Reported-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
Add thread_struct.trap_nr and use it to store the last exception
the thread experienced. In this patch, we populate the field at
various places where we force_sig_info() to the process.
This is also used in uprobes to determine if the probed instruction
caused an exception.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Move is_trap() and relatives to a common file to be shared between kprobes
and uprobes.
Code movement only; no change in functionality.
Suggested by Michael Ellerman.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We have an old FIXME in reg.h which points out that we should standardise
on PVR_foo for our PVR #defines. Currently we use PVR_ on 32-bit and PV_
on 64-bit.
So do that rename and remove the FIXME.
Seeing as we're touching all but one usage of __is_processor(), rename it
to something less ugly and more indicative of what it does, which is
simply to check the PVR version.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The pseries hvterm driver only registers a udbg backend (for xmon and
other low level debugging mechanisms) when hvc0 is recognized as the
firmware console at boot time, not if it's detected later on, for
example because the firmware is using a graphics card.
This can make debugging challenging especially under X11, and there's
really no good reason for that limitation, so let's hookup udbg
whenever hvc0 is detected instead.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
hvc_console has two methods to instanciate the consoles.
hvc_instanciate is meant to be called at early boot, while hvc_alloc is
called for more dynamically probed objects.
Currently, it only deals with adding kernel consoles in the former case,
which means for example that if a console only uses dynamic probing, it
will never be usable as a kernel console even when specifying
console=hvc0 explicitly, which could be considered annoying...
More specifically, on pseries, we only do the early instanciate for the
console currently used by the firmware, so if you have your firmware
configured to go to a video card, for example, you cannot get your
kernel console, oops messages, etc... on your serial port or hypervisor
console, which would be handy to deal with oopses.
This fixes it by checking if hvc_console.flags & CON_ENABLED is set when
registering a new dynamic console, and if not, redo the index check and
re-register the console if the index matches, allowing console=hvcN to
work.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
It contains no code and is not included by anyone.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
It's empty now, apart from other includes.
Fixup a few files that were getting things via this header.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
virt_to_abs() is just a wrapper around __pa(), call __pa() directly.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
These days they are just __va() and __pa() respectively.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
These days they are just __va() and __pa() respectively.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
These days they are just __va() and __pa() respectively.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
abs_to_virt() simply calls __va() and we'd like to get rid of it,
so replace all abs_to_virt() uses with __va().
Similarly virt_to_abs() just calls __pa().
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
abs_to_virt() is just a wrapper around __va(), call __va() directly.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
abs_to_virt() simply calls __va() and we'd like to get rid of it,
so replace all abs_to_virt() uses with __va().
__va() returns void *, so when assigning to a pointer there's no need
to cast.
Similarly virt_to_abs() just calls __pa().
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
These days they are just wrappers around __pa() and __va() respectively.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
These days they are just wrappers around __pa() and __va() respectively.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
abs_to_virt() is just a wrapper around __va(), call __va() directly.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Since commit f5339277 phys_to_abs() is 100% a nop, so just remove it.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
phys_to_abs() is a nop, don't use it.
virt_to_abs() is just a wrapper around __pa(), call __pa() directly.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
In commit f5339277 "powerpc: Remove FW_FEATURE ISERIES from arch code", we
removed the bulk of the iSeries code, but missed a few bits.
Remove the mschunks bits, these were only ever used on iSeries as far as I
know, and are definitely not used anymore.
Make it even clearer that phys_to_abs() is a nop, by making it a macro. We
still have a few users of this, but should clean those up.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
commit a1e636e6d3 (Input: imx_keypad - use clk_prepare_enable/
clk_disable_unprepare()) missed to update clk_enable/clk_disable
in imx_keypad_probe().
Fix it so that we do not get clk warnings at boot.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
