linux-stable.git/arch/arm/kernel/perf_event.c, branch linux-3.10.y Linux kernel stable tree ARM: perf: hook up perf_sample_event_took around pmu irq handling 2014-06-11T19:03:27+00:00 Will Deacon will.deacon@arm.com 2014-02-11T18:08:41+00:00 c318d7b4db9b4f47e0e29c24f4cac6f5e0644dc1 commit 5f5092e72cc25a6a5785308270e0085b2b2772cc upstream. Since we indirect all of our PMU IRQ handling through a dispatcher, it's trivial to hook up perf_sample_event_took to prevent applications such as oprofile from generating interrupt storms due to an unrealisticly low sample period. Reported-by: Robert Richter <rric@kernel.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Weng Meiling <wengmeiling.weng@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5f5092e72cc25a6a5785308270e0085b2b2772cc upstream.

Since we indirect all of our PMU IRQ handling through a dispatcher, it's
trivial to hook up perf_sample_event_took to prevent applications such
as oprofile from generating interrupt storms due to an unrealisticly
low sample period.

Reported-by: Robert Richter <rric@kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: 7809/1: perf: fix event validation for software group leaders 2013-08-20T15:43:05+00:00 Will Deacon will.deacon@arm.com 2013-08-07T22:39:41+00:00 859325460d2b15ef9b78b55eff72d766e1b8ea29 commit c95eb3184ea1a3a2551df57190c81da695e2144b upstream. It is possible to construct an event group with a software event as a group leader and then subsequently add a hardware event to the group. This results in the event group being validated by adding all members of the group to a fake PMU and attempting to allocate each event on their respective PMU. Unfortunately, for software events wthout a corresponding arm_pmu, this results in a kernel crash attempting to dereference the ->get_event_idx function pointer. This patch fixes the problem by checking explicitly for software events and ignoring those in event validation (since they can always be scheduled). We will probably want to revisit this for 3.12, since the validation checks don't appear to work correctly when dealing with multiple hardware PMUs anyway. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Tested-by: Vince Weaver <vincent.weaver@maine.edu> Tested-by: Mark Rutland <mark.rutland@arm.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 c95eb3184ea1a3a2551df57190c81da695e2144b upstream.

It is possible to construct an event group with a software event as a
group leader and then subsequently add a hardware event to the group.
This results in the event group being validated by adding all members
of the group to a fake PMU and attempting to allocate each event on
their respective PMU.

Unfortunately, for software events wthout a corresponding arm_pmu, this
results in a kernel crash attempting to dereference the ->get_event_idx
function pointer.

This patch fixes the problem by checking explicitly for software events
and ignoring those in event validation (since they can always be
scheduled). We will probably want to revisit this for 3.12, since the
validation checks don't appear to work correctly when dealing with
multiple hardware PMUs anyway.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Mark Rutland <mark.rutland@arm.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>
perf/arm: Fix armpmu_map_hw_event() 2013-08-20T15:43:02+00:00 Stephen Boyd sboyd@codeaurora.org 2013-08-07T23:18:08+00:00 b6664dfcf0573495cdea96d2dd37b7d30290ae25 commit b88a2595b6d8aedbd275c07dfa784657b4f757eb upstream. Fix constraint check in armpmu_map_hw_event(). Reported-and-tested-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b88a2595b6d8aedbd275c07dfa784657b4f757eb upstream.

Fix constraint check in armpmu_map_hw_event().

Reported-and-tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: 7765/1: perf: Record the user-mode PC in the call chain. 2013-07-22T01:21:33+00:00 Jed Davis jld@mozilla.com 2013-06-20T09:16:29+00:00 c9f3f7f79f3ee852f253bdb1dbbb43d79bcaa6c2 commit c5f927a6f62196226915f12194c9d0df4e2210d7 upstream. With this change, we no longer lose the innermost entry in the user-mode part of the call chain. See also the x86 port, which includes the ip. It's possible to partially work around this problem by post-processing the data to use the PERF_SAMPLE_IP value, but this works only if the CPU wasn't in the kernel when the sample was taken. Signed-off-by: Jed Davis <jld@mozilla.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 c5f927a6f62196226915f12194c9d0df4e2210d7 upstream.

With this change, we no longer lose the innermost entry in the user-mode
part of the call chain.  See also the x86 port, which includes the ip.

It's possible to partially work around this problem by post-processing
the data to use the PERF_SAMPLE_IP value, but this works only if the CPU
wasn't in the kernel when the sample was taken.

Signed-off-by: Jed Davis <jld@mozilla.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: 7698/1: perf: fix group validation when using enable_on_exec 2013-04-17T15:54:07+00:00 Will Deacon will.deacon@arm.com 2013-04-12T18:04:19+00:00 cb2d8b342aa084d1f3ac29966245dec9163677fb Events may be created with attr->disabled == 1 and attr->enable_on_exec == 1, which confuses the group validation code because events with the PERF_EVENT_STATE_OFF are not considered candidates for scheduling, which may lead to failure at group scheduling time. This patch fixes the validation check for ARM, so that events in the OFF state are still considered when enable_on_exec is true. Cc: stable@vger.kernel.org Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Jiri Olsa <jolsa@redhat.com> Reported-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Events may be created with attr->disabled == 1 and attr->enable_on_exec
== 1, which confuses the group validation code because events with the
PERF_EVENT_STATE_OFF are not considered candidates for scheduling, which
may lead to failure at group scheduling time.

This patch fixes the validation check for ARM, so that events in the
OFF state are still considered when enable_on_exec is true.

Cc: stable@vger.kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Reported-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7667/1: perf: Fix section mismatch on armpmu_init() 2013-03-06T23:45:43+00:00 Stephen Boyd sboyd@codeaurora.org 2013-03-05T02:54:06+00:00 44d6b1fc3e3c6a3af8e599b724972e881c81e1c9 WARNING: vmlinux.o(.text+0xfb80): Section mismatch in reference from the function armpmu_register() to the function .init.text:armpmu_init() The function armpmu_register() references the function __init armpmu_init(). This is often because armpmu_register lacks a __init annotation or the annotation of armpmu_init is wrong. Just drop the __init marking on armpmu_init() because armpmu_register() no longer has an __init marking. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
WARNING: vmlinux.o(.text+0xfb80): Section mismatch in reference
from the function armpmu_register() to the function
.init.text:armpmu_init()
The function armpmu_register() references
the function __init armpmu_init().
This is often because armpmu_register lacks a __init
annotation or the annotation of armpmu_init is wrong.

Just drop the __init marking on armpmu_init() because
armpmu_register() no longer has an __init marking.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7664/1: perf: remove erroneous semicolon from event initialisation 2013-03-03T22:54:17+00:00 Chen Gang gang.chen@asianux.com 2013-02-28T16:51:29+00:00 e595ede6050b1ce982d74f7084f93715bcc32359 Commit 9dcbf466559f ("ARM: perf: simplify __hw_perf_event_init err handling") tidied up the error handling code for perf event initialisation on ARM, but a copy-and-paste error left a dangling semicolon at the end of an if statement. This patch removes the broken semicolon, restoring the old group validation semantics. Cc: Mark Rutland <mark.rutland@arm.com> Acked-by: Dirk Behme <dirk.behme@gmail.com> Signed-off-by: Chen Gang <gang.chen@asianux.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Commit 9dcbf466559f ("ARM: perf: simplify __hw_perf_event_init err
handling") tidied up the error handling code for perf event
initialisation on ARM, but a copy-and-paste error left a dangling
semicolon at the end of an if statement.

This patch removes the broken semicolon, restoring the old group
validation semantics.

Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Dirk Behme <dirk.behme@gmail.com>
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: perf: simplify __hw_perf_event_init err handling 2013-01-18T16:54:30+00:00 Mark Rutland Mark.Rutland@arm.com 2013-01-18T16:10:06+00:00 9dcbf466559f6f2f55d60eb5a1bbebc8e694b52a Currently __hw_perf_event_init has an err variable that's ignored right until the end, where it's initialised, conditionally set, and then used as a boolean flag deciding whether to return another error code. This patch removes the err variable and simplifies the associated error handling logic. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
Currently __hw_perf_event_init has an err variable that's ignored right
until the end, where it's initialised, conditionally set, and then used
as a boolean flag deciding whether to return another error code.

This patch removes the err variable and simplifies the associated error
handling logic.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM: perf: remove unnecessary checks for idx < 0 2013-01-18T13:46:09+00:00 Mark Rutland Mark.Rutland@arm.com 2013-01-18T13:42:59+00:00 8f3b90b585d3e879b03ce2a202da04d59dd5b699 We currently check for hwx->idx < 0 in armpmu_read and armpmu_del unnecessarily. The only case where hwc->idx < 0 is when armpmu_add fails, in which case the event's state is set to PERF_EVENT_STATE_INACTIVE. The perf core will not attempt to read from an event in PERF_EVENT_STATE_INACTIVE, and so the check in armpmu_read is unnecessary. Similarly, if perf core cannot add an event it will not attempt to delete it, so the WARN_ON in armpmu_del is unnecessary. This patch removes these two redundant checks. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
We currently check for hwx->idx < 0 in armpmu_read and armpmu_del
unnecessarily. The only case where hwc->idx < 0 is when armpmu_add
fails, in which case the event's state is set to
PERF_EVENT_STATE_INACTIVE.

The perf core will not attempt to read from an event in
PERF_EVENT_STATE_INACTIVE, and so the check in armpmu_read is
unnecessary. Similarly, if perf core cannot add an event it will not
attempt to delete it, so the WARN_ON in armpmu_del is unnecessary.

This patch removes these two redundant checks.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM: PMU: fix runtime PM enable 2012-11-09T11:37:26+00:00 Jon Hunter jon-hunter@ti.com 2012-10-25T20:23:18+00:00 2ac29a14a8b6b4a37c09c50db88dc893e6e7fc75 Commit 7be2958 (ARM: PMU: Add runtime PM Support) updated the ARM PMU code to use runtime PM which was prototyped and validated on the OMAP devices. In this commit, there is no call pm_runtime_enable() and for OMAP devices pm_runtime_enable() is currently being called from the OMAP PMU code when the PMU device is created. However, there are two problems with this: 1. For any other ARM device wishing to use runtime PM for PMU they will need to call pm_runtime_enable() for runtime PM to work. 2. When booting with device-tree and using device-tree to create the PMU device, pm_runtime_enable() needs to be called from within the ARM PERF driver as we are no longer calling any device specific code to create the device. Hence, PMU does not work on OMAP devices that use the runtime PM callbacks when using device-tree to create the PMU device. Therefore, call pm_runtime_enable() directly from the ARM PMU driver when registering the device. For platforms that do not use runtime PM, pm_runtime_enable() does nothing and for platforms that do use runtime PM but may not require it specifically for PMU, this will just add a little overhead when initialising and uninitialising the PMU device. Tested with PERF on OMAP2420, OMAP3430 and OMAP4460. Acked-by: Kevin Hilman <khilman@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Jon Hunter <jon-hunter@ti.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
Commit 7be2958 (ARM: PMU: Add runtime PM Support) updated the ARM PMU code to
use runtime PM which was prototyped and validated on the OMAP devices. In this
commit, there is no call pm_runtime_enable() and for OMAP devices
pm_runtime_enable() is currently being called from the OMAP PMU code when the
PMU device is created. However, there are two problems with this:

1. For any other ARM device wishing to use runtime PM for PMU they will need
   to call pm_runtime_enable() for runtime PM to work.
2. When booting with device-tree and using device-tree to create the PMU
   device, pm_runtime_enable() needs to be called from within the ARM PERF
   driver as we are no longer calling any device specific code to create the
   device. Hence, PMU does not work on OMAP devices that use the runtime PM
   callbacks when using device-tree to create the PMU device.

Therefore,  call pm_runtime_enable() directly from the ARM PMU driver when
registering the device. For platforms that do not use runtime PM,
pm_runtime_enable() does nothing and for platforms that do use runtime PM but
may not require it specifically for PMU, this will just add a little overhead
when initialising and uninitialising the PMU device.

Tested with PERF on OMAP2420, OMAP3430 and OMAP4460.

Acked-by: Kevin Hilman <khilman@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>