linux.git/arch/powerpc/perf, branch v4.16

Merge branch 'fixes' into next

2018-01-21T12:21:14+00:00

Merge our fixes branch from the 4.15 cycle.

Unusually the fixes branch saw some significant features merged,
notably the RFI flush patches, so we want the code in next to be
tested against that, to avoid any surprises when the two are merged.

There's also some other work on the panic handling that was reverted
in fixes and we now want to do properly in next, which would conflict.

And we also fix a few other minor merge conflicts.

powerpc/perf: Change the data type for the variable 'ncpu' in IMC code

2018-01-19T12:05:01+00:00

Change the data type for the variable 'ncpu' in ppc_core_imc_cpu_offline(),
since cpumask_any_but() returns an 'int' value.

Signed-off-by: Anju T Sudhakar 
Reported-by: David Binderman 
Signed-off-by: Michael Ellerman

powerpc/perf: Pass struct imc_events as a parameter to imc_parse_event()

2018-01-19T12:04:44+00:00

Remove the allocation of struct imc_events from imc_parse_event().
Instead pass imc_events as a parameter to imc_parse_event(), which is
a pointer to a slot in the array allocated in
update_events_in_group().

Reported-by: Dan Carpenter ("powerpc/perf: Fix a sizeof() typo so we allocate less memory")
Suggested-by: Michael Ellerman 
Signed-off-by: Anju T Sudhakar 
Signed-off-by: Michael Ellerman

powerpc/perf: IMC code cleanup with some code refactoring

2018-01-19T11:43:18+00:00

Factor out memory freeing part for attribute elements from
imc_common_cpuhp_mem_free().

Signed-off-by: Anju T Sudhakar 
Reviewed-by: Madhavan Srinivasan 
Signed-off-by: Michael Ellerman

powerpc/perf: Remove thread_imc_pmu global variable from

2018-01-19T11:39:57+00:00

Remove the global variable 'thread_imc_pmu', since it is not used in the code.

Signed-off-by: Anju T Sudhakar 
Reviewed-by: madhavan Srinivasan 
Signed-off-by: Michael Ellerman

powerpc/64: Change soft_enabled from flag to bitmask

2018-01-19T11:37:00+00:00

"paca->soft_enabled" is used as a flag to mask some of interrupts.
Currently supported flags values and their details:

soft_enabled    MSR[EE]

0               0       Disabled (PMI and HMI not masked)
1               1       Enabled

"paca->soft_enabled" is initialized to 1 to make the interripts as
enabled. arch_local_irq_disable() will toggle the value when
interrupts needs to disbled. At this point, the interrupts are not
actually disabled, instead, interrupt vector has code to check for the
flag and mask it when it occurs. By "mask it", it update interrupt
paca->irq_happened and return. arch_local_irq_restore() is called to
re-enable interrupts, which checks and replays interrupts if any
occured.

Now, as mentioned, current logic doesnot mask "performance monitoring
interrupts" and PMIs are implemented as NMI. But this patchset depends
on local_irq_* for a successful local_* update. Meaning, mask all
possible interrupts during local_* update and replay them after the
update.

So the idea here is to reserve the "paca->soft_enabled" logic. New
values and details:

soft_enabled    MSR[EE]

1               0       Disabled  (PMI and HMI not masked)
0               1       Enabled

Reason for the this change is to create foundation for a third mask
value "0x2" for "soft_enabled" to add support to mask PMIs. When
->soft_enabled is set to a value "3", PMI interrupts are mask and when
set to a value of "1", PMI are not mask. With this patch also extends
soft_enabled as interrupt disable mask.

Current flags are renamed from IRQ_[EN?DIS}ABLED to
IRQS_ENABLED and IRQS_DISABLED.

Patch also fixes the ptrace call to force the user to see the softe
value to be alway 1. Reason being, even though userspace has no
business knowing about softe, it is part of pt_regs. Like-wise in
signal context.

Signed-off-by: Madhavan Srinivasan 
Signed-off-by: Michael Ellerman

powerpc/64: Add #defines for paca->soft_enabled flags

2018-01-19T11:36:56+00:00

Two #defines IRQS_ENABLED and IRQS_DISABLED are added to be used when
updating paca->soft_enabled. Replace the hardcoded values used when
updating paca->soft_enabled with IRQ_(EN|DIS)ABLED #define. No logic
change.

Reviewed-by: Nicholas Piggin 
Signed-off-by: Madhavan Srinivasan 
Signed-off-by: Michael Ellerman

powerpc/8xx: Only perform perf counting when perf is in use.

2018-01-16T12:47:12+00:00

In TLB miss handlers, updating the perf counter is only useful
when performing a perf analysis. As it has a noticeable overhead,
let's only do it when needed.

In order to do so, the exit of the miss handlers will be patched
when starting/stopping 'perf': the first register restore
instruction of each exit point will be replaced by a jump to
the counting code.

Once this is done, CONFIG_PPC_8xx_PERF_EVENT becomes useless as
this feature doesn't add any overhead.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman

powerpc/perf: Fix kfree memory allocated for nest pmus

2017-12-13T09:51:22+00:00

imc_common_cpuhp_mem_free() is the common function for all
IMC (In-memory Collection counters) domains to unregister cpuhotplug
callback and free memory. Since kfree of memory allocated for
nest-imc (per_nest_pmu_arr) is in the common code, all
domains (core/nest/thread) can do the kfree in the failure case.

This could potentially create a call trace as shown below, where
core(/thread/nest) imc pmu initialization fails and in the failure
path imc_common_cpuhp_mem_free() free the memory(per_nest_pmu_arr),
which is allocated by successfully registered nest units.

The call trace is generated in a scenario where core-imc
initialization is made to fail and a cpuhotplug is performed in a p9
system. During cpuhotplug ppc_nest_imc_cpu_offline() tries to access
per_nest_pmu_arr, which is already freed by core-imc.

  NIP [c000000000cb6a94] mutex_lock+0x34/0x90
  LR [c000000000cb6a88] mutex_lock+0x28/0x90
  Call Trace:
    mutex_lock+0x28/0x90 (unreliable)
    perf_pmu_migrate_context+0x90/0x3a0
    ppc_nest_imc_cpu_offline+0x190/0x1f0
    cpuhp_invoke_callback+0x160/0x820
    cpuhp_thread_fun+0x1bc/0x270
    smpboot_thread_fn+0x250/0x290
    kthread+0x1a8/0x1b0
    ret_from_kernel_thread+0x5c/0x74

To address this scenario do the kfree(per_nest_pmu_arr) only in case
of nest-imc initialization failure, and when there is no other nest
units registered.

Fixes: 73ce9aec65b1 ("powerpc/perf: Fix IMC_MAX_PMU macro")
Signed-off-by: Anju T Sudhakar 
Reviewed-by: Madhavan Srinivasan 
Signed-off-by: Michael Ellerman

powerpc/perf/imc: Fix nest-imc cpuhotplug callback failure

2017-12-13T09:36:53+00:00

Oops is observed during boot:

  Faulting instruction address: 0xc000000000248340
  cpu 0x0: Vector: 380 (Data Access Out of Range) at [c000000ff66fb850]
      pc: c000000000248340: event_function_call+0x50/0x1f0
      lr: c00000000024878c: perf_remove_from_context+0x3c/0x100
      sp: c000000ff66fbad0
     msr: 9000000000009033
     dar: 7d20e2a6f92d03c0
    pid = 14, comm = cpuhp/0

While registering the cpuhotplug callbacks for nest-imc, if we fail in
the cpuhotplug online path for any random node in a multi node
system (because the opal call to stop nest-imc counters fails for that
node), ppc_nest_imc_cpu_offline() will get invoked for other nodes who
successfully returned from cpuhotplug online path.

This call trace is generated since in the ppc_nest_imc_cpu_offline()
path we are trying to migrate the event context, when nest-imc
counters are not even initialized.

Patch to add a check to ensure that nest-imc is registered before
migrating the event context.

Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support")
Signed-off-by: Anju T Sudhakar 
Reviewed-by: Madhavan Srinivasan 
Signed-off-by: Michael Ellerman