linux-toradex.git/arch/arm/kernel/perf_event.c, branch v3.2.20 Linux kernel for Apalis and Colibri modules ARM: 7354/1: perf: limit sample_period to half max_period in non-sampling mode 2012-03-12T19:31:38+00:00 Will Deacon will.deacon@arm.com 2012-03-06T16:33:17+00:00 14e84b15bcd96521190c5566c440c56553e66fc9 commit 5727347180ebc6b4a866fcbe00dcb39cc03acb37 upstream. On ARM, the PMU does not stop counting after an overflow and therefore IRQ latency affects the new counter value read by the kernel. This is significant for non-sampling runs where it is possible for the new value to overtake the previous one, causing the delta to be out by up to max_period events. Commit a737823d ("ARM: 6835/1: perf: ensure overflows aren't missed due to IRQ latency") attempted to fix this problem by allowing interrupt handlers to pass an overflow flag to the event update function, causing the overflow calculation to assume that the counter passed through zero when going from prev to new. Unfortunately, this doesn't work when overflow occurs on the perf_task_tick path because we have the flag cleared and end up computing a large negative delta. This patch removes the overflow flag from armpmu_event_update and instead limits the sample_period to half of the max_period for non-sampling profiling runs. Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5727347180ebc6b4a866fcbe00dcb39cc03acb37 upstream.

On ARM, the PMU does not stop counting after an overflow and therefore
IRQ latency affects the new counter value read by the kernel. This is
significant for non-sampling runs where it is possible for the new value
to overtake the previous one, causing the delta to be out by up to
max_period events.

Commit a737823d ("ARM: 6835/1: perf: ensure overflows aren't missed due
to IRQ latency") attempted to fix this problem by allowing interrupt
handlers to pass an overflow flag to the event update function, causing
the overflow calculation to assume that the counter passed through zero
when going from prev to new. Unfortunately, this doesn't work when
overflow occurs on the perf_task_tick path because we have the flag
cleared and end up computing a large negative delta.

This patch removes the overflow flag from armpmu_event_update and
instead limits the sample_period to half of the max_period for
non-sampling profiling runs.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: 7185/1: perf: don't assign platform_device on unsupported CPUs 2011-12-06T12:48:01+00:00 Will Deacon will.deacon@arm.com 2011-12-02T17:16:01+00:00 6bd054096dce061560cee0e016e292e588dc438f In the unlikely case that a platform registers a PMU platform_device when running on a CPU that is unsupported by perf, we will encounter a NULL dereference when trying to assign the platform_device to the cpu_pmu structure. This patch checks that the CPU is supported by perf before assigning the platform_device. Reported-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
In the unlikely case that a platform registers a PMU platform_device
when running on a CPU that is unsupported by perf, we will encounter a
NULL dereference when trying to assign the platform_device to the
cpu_pmu structure.

This patch checks that the CPU is supported by perf before assigning
the platform_device.

Reported-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-12-06T00:54:00+00:00 Linus Torvalds torvalds@linux-foundation.org 2011-12-06T00:54:00+00:00 232ea344550c4a099d35d9df552509d6748a31c0 * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix loss of notification with multi-event perf, x86: Force IBS LVT offset assignment for family 10h perf, x86: Disable PEBS on SandyBridge chips trace_events_filter: Use rcu_assign_pointer() when setting ftrace_event_call->filter perf session: Fix crash with invalid CPU list perf python: Fix undefined symbol problem perf/x86: Enable raw event access to Intel offcore events perf: Don't use -ENOSPC for out of PMU resources perf: Do not set task_ctx pointer in cpuctx if there are no events in the context perf/x86: Fix PEBS instruction unwind oprofile, x86: Fix crash when unloading module (nmi timer mode) oprofile: Fix crash when unloading module (hr timer mode) 
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix loss of notification with multi-event
  perf, x86: Force IBS LVT offset assignment for family 10h
  perf, x86: Disable PEBS on SandyBridge chips
  trace_events_filter: Use rcu_assign_pointer() when setting ftrace_event_call->filter
  perf session: Fix crash with invalid CPU list
  perf python: Fix undefined symbol problem
  perf/x86: Enable raw event access to Intel offcore events
  perf: Don't use -ENOSPC for out of PMU resources
  perf: Do not set task_ctx pointer in cpuctx if there are no events in the context
  perf/x86: Fix PEBS instruction unwind
  oprofile, x86: Fix crash when unloading module (nmi timer mode)
  oprofile: Fix crash when unloading module (hr timer mode)
ARM: perf: check that we have a platform device when reserving PMU 2011-11-22T18:01:46+00:00 Will Deacon will.deacon@arm.com 2011-11-22T18:01:46+00:00 e5a21327644adba32816f74a415114d11c57f2e9 Attempting to use a hardware counter on a platform with a supported PMU but where the platform_device (defining the interrupts) has not been registered results in a NULL pointer dereference. This patch fixes the problem by checking that we actually have a platform device registered before attempting to grab the interrupts. Reported-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
Attempting to use a hardware counter on a platform with a supported PMU
but where the platform_device (defining the interrupts) has not been
registered results in a NULL pointer dereference.

This patch fixes the problem by checking that we actually have a platform
device registered before attempting to grab the interrupts.

Reported-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM: perf: initialise used_mask for fake PMU during validation 2011-11-17T15:20:03+00:00 Will Deacon will.deacon@arm.com 2011-11-17T15:05:14+00:00 bce34d14428d35d9a06ddc10cd46ecef311764c9 When validating an event group, we call pmu->get_event_idx for each group member in order to check that the group can be scheduled as a unit on an empty PMU. As a result of 3fc2c830 ("ARM: perf: remove event limit from pmu_hw_events"), the used_mask member of struct cpu_hw_events must be setup explicitly, something which we don't do for the fake cpu_hw_events used for validation. This patch sets up an empty used_mask for the fake validation cpu_hw_events, preventing NULL deferences when trying to get the event index. Reported-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
When validating an event group, we call pmu->get_event_idx for each
group member in order to check that the group can be scheduled as a
unit on an empty PMU.

As a result of 3fc2c830 ("ARM: perf: remove event limit from
pmu_hw_events"), the used_mask member of struct cpu_hw_events must be
setup explicitly, something which we don't do for the fake cpu_hw_events
used for validation.

This patch sets up an empty used_mask for the fake validation
cpu_hw_events, preventing NULL deferences when trying to get the event
index.

Reported-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
perf: Don't use -ENOSPC for out of PMU resources 2011-11-14T12:01:24+00:00 Peter Zijlstra a.p.zijlstra@chello.nl 2011-11-09T16:56:37+00:00 aa2bc1ade59003a379ffc485d6da2d92ea3370a6 People (Linus) objected to using -ENOSPC to signal not having enough resources on the PMU to satisfy the request. Use -EINVAL. Requested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Stephane Eranian <eranian@google.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com> Cc: David Daney <david.daney@cavium.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-xv8geaz2zpbjhlx0svmpp28n@git.kernel.org [ merged to newer kernel, fixed up MIPS impact ] Signed-off-by: Ingo Molnar <mingo@elte.hu> 
People (Linus) objected to using -ENOSPC to signal not having enough
resources on the PMU to satisfy the request. Use -EINVAL.

Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-xv8geaz2zpbjhlx0svmpp28n@git.kernel.org
[ merged to newer kernel, fixed up MIPS impact ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arm: convert core files from module.h to export.h 2011-10-31T23:30:49+00:00 Paul Gortmaker paul.gortmaker@windriver.com 2011-07-22T14:58:34+00:00 ecea4ab6d3d8bb4122522398200f1cd2a06af6d5 Many of the core ARM kernel files are not modules, but just including module.h for exporting symbols. Now these files can use the lighter footprint export.h for this role. There are probably lots more, but ARM files of mach-* and plat-* don't get coverage via a simple yesconfig build. They will have to be cleaned up and tested via using their respective configs. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> 
Many of the core ARM kernel files are not modules, but just
including module.h for exporting symbols.  Now these files can
use the lighter footprint export.h for this role.

There are probably lots more, but ARM files of mach-* and plat-*
don't get coverage via a simple yesconfig build.  They will have
to be cleaned up and tested via using their respective configs.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
ARM: perf: Remove unnecessary armpmu->enable()s 2011-08-31T09:50:13+00:00 Mark Rutland mark.rutland@arm.com 2011-08-23T10:59:49+00:00 7325eaec439cd0cc8c9b61b59d41d99abace1b23 Currently, armpmu_enable iterates through the events for a given counter set, calling armpmu->enable on each before calling armpmu->start to start the PMU's counters. As armpmu->enable is called when each event is added, each event is already configured in hardware. Due to this, calling armpmu->enable in armpmu_enable is unnecessary and confusing. This patch removes the unnecessary calls to armpmu->enable. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
Currently, armpmu_enable iterates through the events for a given
counter set, calling armpmu->enable on each before calling
armpmu->start to start the PMU's counters.

As armpmu->enable is called when each event is added, each event is
already configured in hardware. Due to this, calling armpmu->enable
in armpmu_enable is unnecessary and confusing.

This patch removes the unnecessary calls to armpmu->enable.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM: perf: move arm_pmu into <asm/pmu.h> 2011-08-31T09:50:13+00:00 Mark Rutland mark.rutland@arm.com 2011-05-19T09:07:57+00:00 0ce47080dfffe71edd433b35dcdada24c61079eb Currently, struct arm_pmu and related functions are only visible to {,arch/arm/}/kernel/perf_event.c. This prevents new drivers from using the framework. This patch moves declarations to asm/pmu.h, allowing new PMU drivers to use the framework. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Jamie Iles <jamie@jamieiles.com> Reviewed-by: Ashwin Chaugule <ashwinc@codeaurora.org> Signed-off-by: Will Deacon <will.deacon@arm.com> 
Currently, struct arm_pmu and related functions are only visible to
{,arch/arm/}/kernel/perf_event.c. This prevents new drivers from using
the framework.

This patch  moves declarations to asm/pmu.h, allowing new PMU drivers
to use the framework.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Ashwin Chaugule <ashwinc@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM: perf: remove cpu-related misnomers 2011-08-31T09:50:12+00:00 Mark Rutland mark.rutland@arm.com 2011-05-17T10:20:11+00:00 8be3f9a2385f91f7bf5c58f351e24b9247898e8f Currently struct cpu_hw_events stores data on events running on a PMU associated with a CPU. As this data is general enough to be used for system PMUs, this name is a misnomer, and may cause confusion when it is used for system PMUs. Additionally, 'armpmu' is commonly used as a parameter name for an instance of struct arm_pmu. The name is also used for a global instance which represents the CPU's PMU. As cpu_hw_events is now not tied to CPU PMUs, it is renamed to pmu_hw_events, with instances of it renamed similarly. As the global 'armpmu' is CPU-specfic, it is renamed to cpu_pmu. This should make it clearer which code is generic, and which is coupled with the CPU. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Jamie Iles <jamie@jamieiles.com> Reviewed-by: Ashwin Chaugule <ashwinc@codeaurora.org> Signed-off-by: Will Deacon <will.deacon@arm.com> 
Currently struct cpu_hw_events stores data on events running on a
PMU associated with a CPU. As this data is general enough to be used
for system PMUs, this name is a misnomer, and may cause confusion when
it is used for system PMUs.

Additionally, 'armpmu' is commonly used as a parameter name for an
instance of struct arm_pmu. The name is also used for a global instance
which represents the CPU's PMU.

As cpu_hw_events is now not tied to CPU PMUs, it is renamed to
pmu_hw_events, with instances of it renamed similarly. As the global
'armpmu' is CPU-specfic, it is renamed to cpu_pmu. This should make it
clearer which code is generic, and which is coupled with the CPU.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Ashwin Chaugule <ashwinc@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>