linux-toradex.git/arch/powerpc/kernel, branch v3.14.15

powerpc: Don't skip ePAPR spin-table CPUs

2014-07-07T01:57:28+00:00

commit 6663a4fa6711050036562ddfd2086edf735fae21 upstream.

Commit 59a53afe70fd530040bdc69581f03d880157f15a "powerpc: Don't setup
CPUs with bad status" broke ePAPR SMP booting.  ePAPR says that CPUs
that aren't presently running shall have status of disabled, with
enable-method being used to determine whether the CPU can be enabled.

Fix by checking for spin-table, which is currently the only supported
enable-method.

Signed-off-by: Scott Wood 
Cc: Michael Neuling 
Cc: Emil Medve 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Add AT_HWCAP2 to indicate V.CRYPTO category support

2014-07-07T01:57:28+00:00

commit dd58a092c4202f2bd490adab7285b3ff77f8e467 upstream.

The Vector Crypto category instructions are supported by current POWER8
chips, advertise them to userspace using a specific bit to properly
differentiate with chips of the same architecture level that might not
have them.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Don't setup CPUs with bad status

2014-07-07T01:57:28+00:00

commit 59a53afe70fd530040bdc69581f03d880157f15a upstream.

OPAL will mark a CPU that is guarded as "bad" in the status property of the CPU
node.

Unfortunatley Linux doesn't check this property and will put the bad CPU in the
present map.  This has caused hangs on booting when we try to unsplit the core.

This patch checks the CPU is avaliable via this status property before putting
it in the present map.

Signed-off-by: Michael Neuling 
Tested-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: fix typo 'CONFIG_PMAC'

2014-07-07T01:57:28+00:00

commit 6e0fdf9af216887e0032c19d276889aad41cad00 upstream.

Commit b0d278b7d3ae ("powerpc/perf_event: Reduce latency of calling
perf_event_do_pending") added a check for CONFIG_PMAC were a check for
CONFIG_PPC_PMAC was clearly intended.

Fixes: b0d278b7d3ae ("powerpc/perf_event: Reduce latency of calling perf_event_do_pending")
Signed-off-by: Paul Bolle 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/serial: Use saner flags when creating legacy ports

2014-07-07T01:57:28+00:00

commit c4cad90f9e9dcb85afc5e75a02ae3522ed077296 upstream.

We had a mix & match of flags used when creating legacy ports
depending on where we found them in the device-tree. Among others
we were missing UPF_SKIP_TEST for some kind of ISA ports which is
a problem as quite a few UARTs out there don't support the loopback
test (such as a lot of BMCs).

Let's pick the set of flags used by the SoC code and generalize it
which means autoconf, no loopback test, irq maybe shared and fixed
port.

Sending to stable as the lack of UPF_SKIP_TEST is breaking
serial on some machines so I want this back into distros

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc, kexec: Fix "Processor X is stuck" issue during kexec from ST mode

2014-06-07T17:28:28+00:00

commit 011e4b02f1da156ac7fea28a9da878f3c23af739 upstream.

If we try to perform a kexec when the machine is in ST (Single-Threaded) mode
(ppc64_cpu --smt=off), the kexec operation doesn't succeed properly, and we
get the following messages during boot:

[    0.089866] POWER8 performance monitor hardware support registered
[    0.089985] power8-pmu: PMAO restore workaround active.
[    5.095419] Processor 1 is stuck.
[   10.097933] Processor 2 is stuck.
[   15.100480] Processor 3 is stuck.
[   20.102982] Processor 4 is stuck.
[   25.105489] Processor 5 is stuck.
[   30.108005] Processor 6 is stuck.
[   35.110518] Processor 7 is stuck.
[   40.113369] Processor 9 is stuck.
[   45.115879] Processor 10 is stuck.
[   50.118389] Processor 11 is stuck.
[   55.120904] Processor 12 is stuck.
[   60.123425] Processor 13 is stuck.
[   65.125970] Processor 14 is stuck.
[   70.128495] Processor 15 is stuck.
[   75.131316] Processor 17 is stuck.

Note that only the sibling threads are stuck, while the primary threads (0, 8,
16 etc) boot just fine. Looking closer at the previous step of kexec, we observe
that kexec tries to wakeup (bring online) the sibling threads of all the cores,
before performing kexec:

[ 9464.131231] Starting new kernel
[ 9464.148507] kexec: Waking offline cpu 1.
[ 9464.148552] kexec: Waking offline cpu 2.
[ 9464.148600] kexec: Waking offline cpu 3.
[ 9464.148636] kexec: Waking offline cpu 4.
[ 9464.148671] kexec: Waking offline cpu 5.
[ 9464.148708] kexec: Waking offline cpu 6.
[ 9464.148743] kexec: Waking offline cpu 7.
[ 9464.148779] kexec: Waking offline cpu 9.
[ 9464.148815] kexec: Waking offline cpu 10.
[ 9464.148851] kexec: Waking offline cpu 11.
[ 9464.148887] kexec: Waking offline cpu 12.
[ 9464.148922] kexec: Waking offline cpu 13.
[ 9464.148958] kexec: Waking offline cpu 14.
[ 9464.148994] kexec: Waking offline cpu 15.
[ 9464.149030] kexec: Waking offline cpu 17.

Instrumenting this piece of code revealed that the cpu_up() operation actually
fails with -EBUSY. Thus, only the primary threads of all the cores are online
during kexec, and hence this is a sure-shot receipe for disaster, as explained
in commit e8e5c2155b (powerpc/kexec: Fix orphaned offline CPUs across kexec),
as well as in the comment above wake_offline_cpus().

It turns out that cpu_up() was returning -EBUSY because the variable
'cpu_hotplug_disabled' was set to 1; and this disabling of CPU hotplug was done
by migrate_to_reboot_cpu() inside kernel_kexec().

Now, migrate_to_reboot_cpu() was originally written with the assumption that
any further code will not need to perform CPU hotplug, since we are anyway in
the reboot path. However, kexec is clearly not such a case, since we depend on
onlining CPUs, atleast on powerpc.

So re-enable cpu-hotplug after returning from migrate_to_reboot_cpu() in the
kexec path, to fix this regression in kexec on powerpc.

Also, wrap the cpu_up() in powerpc kexec code within a WARN_ON(), so that we
can catch such issues more easily in the future.

Fixes: c97102ba963 (kexec: migrate to reboot cpu)
Signed-off-by: Srivatsa S. Bhat 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: irq work racing with timer interrupt can result in timer interrupt hang

2014-06-07T17:28:28+00:00

commit 8050936caf125fbe54111ba5e696b68a360556ba upstream.

I am seeing an issue where a CPU running perf eventually hangs.
Traces show timer interrupts happening every 4 seconds even
when a userspace task is running on the CPU. /proc/timer_list
also shows pending hrtimers have not run in over an hour,
including the scheduler.

Looking closer, decrementers_next_tb is getting set to
0xffffffffffffffff, and at that point we will never take
a timer interrupt again.

In __timer_interrupt() we set decrementers_next_tb to
0xffffffffffffffff and rely on ->event_handler to update it:

        *next_tb = ~(u64)0;
        if (evt->event_handler)
                evt->event_handler(evt);

In this case ->event_handler is hrtimer_interrupt. This will eventually
call back through the clockevents code with the next event to be
programmed:

static int decrementer_set_next_event(unsigned long evt,
                                      struct clock_event_device *dev)
{
        /* Don't adjust the decrementer if some irq work is pending */
        if (test_irq_work_pending())
                return 0;
        __get_cpu_var(decrementers_next_tb) = get_tb_or_rtc() + evt;

If irq work came in between these two points, we will return
before updating decrementers_next_tb and we never process a timer
interrupt again.

This looks to have been introduced by 0215f7d8c53f (powerpc: Fix races
with irq_work). Fix it by removing the early exit and relying on
code later on in the function to force an early decrementer:

       /* We may have raced with new irq work */
       if (test_irq_work_pending())
               set_dec(1);

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/tm: Disable IRQ in tm_recheckpoint

2014-05-13T11:32:49+00:00

commit e6b8fd028b584ffca7a7255b8971f254932c9fce upstream.

We can't take an IRQ when we're about to do a trechkpt as our GPR state is set
to user GPR values.

We've hit this when running some IBM Java stress tests in the lab resulting in
the following dump:

  cpu 0x3f: Vector: 700 (Program Check) at [c000000007eb3d40]
      pc: c000000000050074: restore_gprs+0xc0/0x148
      lr: 00000000b52a8184
      sp: ac57d360
     msr: 8000000100201030
    current = 0xc00000002c500000
    paca    = 0xc000000007dbfc00     softe: 0     irq_happened: 0x00
      pid   = 34535, comm = Pooled Thread #
  R00 = 00000000b52a8184   R16 = 00000000b3e48fda
  R01 = 00000000ac57d360   R17 = 00000000ade79bd8
  R02 = 00000000ac586930   R18 = 000000000fac9bcc
  R03 = 00000000ade60000   R19 = 00000000ac57f930
  R04 = 00000000f6624918   R20 = 00000000ade79be8
  R05 = 00000000f663f238   R21 = 00000000ac218a54
  R06 = 0000000000000002   R22 = 000000000f956280
  R07 = 0000000000000008   R23 = 000000000000007e
  R08 = 000000000000000a   R24 = 000000000000000c
  R09 = 00000000b6e69160   R25 = 00000000b424cf00
  R10 = 0000000000000181   R26 = 00000000f66256d4
  R11 = 000000000f365ec0   R27 = 00000000b6fdcdd0
  R12 = 00000000f66400f0   R28 = 0000000000000001
  R13 = 00000000ada71900   R29 = 00000000ade5a300
  R14 = 00000000ac2185a8   R30 = 00000000f663f238
  R15 = 0000000000000004   R31 = 00000000f6624918
  pc  = c000000000050074 restore_gprs+0xc0/0x148
  cfar= c00000000004fe28 dont_restore_vec+0x1c/0x1a4
  lr  = 00000000b52a8184
  msr = 8000000100201030   cr  = 24804888
  ctr = 0000000000000000   xer = 0000000000000000   trap =  700

This moves tm_recheckpoint to a C function and moves the tm_restore_sprs into
that function.  It then adds IRQ disabling over the trechkpt critical section.
It also sets the TEXASR FS in the signals code to ensure this is never set now
that we explictly write the TM sprs in tm_recheckpoint.

Signed-off-by: Michael Neuling 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Align p_dyn, p_rela and p_st symbols

2014-03-07T02:50:19+00:00

The 64bit relocation code places a few symbols in the text segment.
These symbols are only 4 byte aligned where they need to be 8 byte
aligned. Add an explicit alignment.

Signed-off-by: Anton Blanchard 
Cc: stable@vger.kernel.org
Tested-by: Laurent Dufour 
Signed-off-by: Benjamin Herrenschmidt

powerpc/tm: Fix crash when forking inside a transaction

2014-03-07T02:50:15+00:00

When we fork/clone we currently don't copy any of the TM state to the new
thread.  This results in a TM bad thing (program check) when the new process is
switched in as the kernel does a tmrechkpt with TEXASR FS not set.  Also, since
R1 is from userspace, we trigger the bad kernel stack pointer detection.  So we
end up with something like this:

   Bad kernel stack pointer 0 at c0000000000404fc
   cpu 0x2: Vector: 700 (Program Check) at [c00000003ffefd40]
       pc: c0000000000404fc: restore_gprs+0xc0/0x148
       lr: 0000000000000000
       sp: 0
      msr: 9000000100201030
     current = 0xc000001dd1417c30
     paca    = 0xc00000000fe00800   softe: 0        irq_happened: 0x01
       pid   = 0, comm = swapper/2
   WARNING: exception is not recoverable, can't continue

The below fixes this by flushing the TM state before we copy the task_struct to
the clone.  To do this we go through the tmreclaim patch, which removes the
checkpointed registers from the CPU and transitions the CPU out of TM suspend
mode.  Hence we need to call tmrechkpt after to restore the checkpointed state
and the TM mode for the current task.

To make this fail from userspace is simply:
	tbegin
	li	r0, 2
	sc
	

Kudos to Adhemerval Zanella Neto for finding this.

Signed-off-by: Michael Neuling 
cc: Adhemerval Zanella Neto 
cc: stable@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt