[PATCH v4 0/5] MIPS/Perf-events: Sync with mainline upper layer (v4)

[PATCH v4 0/5] MIPS/Perf-events: Sync with mainline upper layer (v4)

[Deng-Cheng Zhu]

Current MIPS Perf-events uses older interfaces to the generic layer. So it
will not work. This patch set fixes this issue (reported by Wu Zhangjin) by
adding MIPS counterparts for a list of previous commits that went to
mainline earlier.

Changes:
v4 - v3:
o Rebase this patch set to have early_initcall instead of arch_initcall for
init_hw_perf_events.
o Change the arguments of perf_pmu_register() in Patch #2.
v3 - v2:
o Keep all mentioned commits in the form of number + title + original
summary + (MIPS specific info when needed).
v2 - v1:
o Corrected the return value of the event check in validate_event().

Deng-Cheng Zhu (5):
  MIPS/Perf-events: Work with irq_work
  MIPS/Perf-events: Work with the new PMU interface
  MIPS/Perf-events: Fix event check in validate_event()
  MIPS/Perf-events: Work with the new callchain interface
  MIPS/Perf-events: Use unsigned delta for right shift in event update

 arch/mips/Kconfig                    |    1 +
 arch/mips/include/asm/perf_event.h   |   12 +-
 arch/mips/kernel/perf_event.c        |  345 ++++++++++++++++------------------
 arch/mips/kernel/perf_event_mipsxx.c |    4 +-
 4 files changed, 171 insertions(+), 191 deletions(-)

[PATCH v4 1/5] MIPS/Perf-events: Work with irq_work

[Deng-Cheng Zhu]

This is the MIPS part of the following commit by Peter Zijlstra:

- e360adbe29241a0194e10e20595360dd7b98a2b3
    irq_work: Add generic hardirq context callbacks

    Provide a mechanism that allows running code in IRQ context. It is
    most useful for NMI code that needs to interact with the rest of the
    system -- like wakeup a task to drain buffers.

    Perf currently has such a mechanism, so extract that and provide it as
    a generic feature, independent of perf so that others may also
    benefit.

    The IRQ context callback is generated through self-IPIs where
    possible, or on architectures like powerpc the decrementer (the
    built-in timer facility) is set to generate an interrupt immediately.

    Architectures that don't have anything like this get to do with a
    callback from the timer tick. These architectures can call
    irq_work_run() at the tail of any IRQ handlers that might enqueue such
    work (like the perf IRQ handler) to avoid undue latencies in
    processing the work.

For MIPSXX, we need to call irq_work_run() at the tail of the perf IRQ
handler as described above.

Changes:
v4 - v3:
o None
v3 - v2:
o Keep all mentioned commits in the form of number + title + original
summary + (MIPS specific info when needed).
v2 - v1:
o None

Reported-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
---
 arch/mips/Kconfig                    |    1 +
 arch/mips/include/asm/perf_event.h   |   12 +-----------
 arch/mips/kernel/perf_event_mipsxx.c |    2 +-
 3 files changed, 3 insertions(+), 12 deletions(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 67a2fa2..c44c38d 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -4,6 +4,7 @@ config MIPS
 	select HAVE_GENERIC_DMA_COHERENT
 	select HAVE_IDE
 	select HAVE_OPROFILE
+	select HAVE_IRQ_WORK
 	select HAVE_PERF_EVENTS
 	select PERF_USE_VMALLOC
 	select HAVE_ARCH_KGDB
diff --git a/arch/mips/include/asm/perf_event.h b/arch/mips/include/asm/perf_event.h
index e00007c..d0c7749 100644
--- a/arch/mips/include/asm/perf_event.h
+++ b/arch/mips/include/asm/perf_event.h
@@ -11,15 +11,5 @@
 
 #ifndef __MIPS_PERF_EVENT_H__
 #define __MIPS_PERF_EVENT_H__
-
-/*
- * MIPS performance counters do not raise NMI upon overflow, a regular
- * interrupt will be signaled. Hence we can do the pending perf event
- * work at the tail of the irq handler.
- */
-static inline void
-set_perf_event_pending(void)
-{
-}
-
+/* Leave it empty here. The file is required by linux/perf_event.h */
 #endif /* __MIPS_PERF_EVENT_H__ */
diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index 5c7c6fc..fa00edc 100644
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/arch/mips/kernel/perf_event_mipsxx.c
@@ -696,7 +696,7 @@ static int mipsxx_pmu_handle_shared_irq(void)
 	 * interrupt, not NMI.
 	 */
 	if (handled == IRQ_HANDLED)
-		perf_event_do_pending();
+		irq_work_run();
 
 #ifdef CONFIG_MIPS_MT_SMP
 	read_unlock(&pmuint_rwlock);
-- 
1.7.1

[PATCH v4 2/5] MIPS/Perf-events: Work with the new PMU interface

[Deng-Cheng Zhu]

This is the MIPS part of the following commits by Peter Zijlstra:

- a4eaf7f14675cb512d69f0c928055e73d0c6d252
    perf: Rework the PMU methods

    Replace pmu::{enable,disable,start,stop,unthrottle} with
    pmu::{add,del,start,stop}, all of which take a flags argument.

    The new interface extends the capability to stop a counter while
    keeping it scheduled on the PMU. We replace the throttled state with
    the generic stopped state.

    This also allows us to efficiently stop/start counters over certain
    code paths (like IRQ handlers).

    It also allows scheduling a counter without it starting, allowing for
    a generic frozen state (useful for rotating stopped counters).

    The stopped state is implemented in two different ways, depending on
    how the architecture implemented the throttled state:

     1) We disable the counter:
        a) the pmu has per-counter enable bits, we flip that
        b) we program a NOP event, preserving the counter state

     2) We store the counter state and ignore all read/overflow events

For MIPSXX, the stopped state is implemented in the way of 1.b as above.

- 33696fc0d141bbbcb12f75b69608ea83282e3117
    perf: Per PMU disable

    Changes perf_disable() into perf_pmu_disable().

- 24cd7f54a0d47e1d5b3de29e2456bfbd2d8447b7
    perf: Reduce perf_disable() usage

    Since the current perf_disable() usage is only an optimization,
    remove it for now. This eases the removal of the __weak
    hw_perf_enable() interface.

- b0a873ebbf87bf38bf70b5e39a7cadc96099fa13
    perf: Register PMU implementations

    Simple registration interface for struct pmu, this provides the
    infrastructure for removing all the weak functions.

- 51b0fe39549a04858001922919ab355dee9bdfcf
    perf: Deconstify struct pmu

    sed -ie 's/const struct pmu\>/struct pmu/g' `git grep -l "const struct pmu\>"`

Changes:
v4 - v3:
o Rebase this patch set to have early_initcall instead of arch_initcall for
init_hw_perf_events.
o Change the arguments of perf_pmu_register().
v3 - v2:
o Keep all mentioned commits in the form of number + title + original
summary + (MIPS specific info when needed).
v2 - v1:
o None 

Reported-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
---
 arch/mips/kernel/perf_event.c        |  275 +++++++++++++++++++---------------
 arch/mips/kernel/perf_event_mipsxx.c |    2 +
 2 files changed, 158 insertions(+), 119 deletions(-)

diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
index 2b7f3f7..1ee44a3 100644
--- a/arch/mips/kernel/perf_event.c
+++ b/arch/mips/kernel/perf_event.c
@@ -161,41 +161,6 @@ mipspmu_event_set_period(struct perf_event *event,
 	return ret;
 }
 
-static int mipspmu_enable(struct perf_event *event)
-{
-	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
-	struct hw_perf_event *hwc = &event->hw;
-	int idx;
-	int err = 0;
-
-	/* To look for a free counter for this event. */
-	idx = mipspmu->alloc_counter(cpuc, hwc);
-	if (idx < 0) {
-		err = idx;
-		goto out;
-	}
-
-	/*
-	 * If there is an event in the counter we are going to use then
-	 * make sure it is disabled.
-	 */
-	event->hw.idx = idx;
-	mipspmu->disable_event(idx);
-	cpuc->events[idx] = event;
-
-	/* Set the period for the event. */
-	mipspmu_event_set_period(event, hwc, idx);
-
-	/* Enable the event. */
-	mipspmu->enable_event(hwc, idx);
-
-	/* Propagate our changes to the userspace mapping. */
-	perf_event_update_userpage(event);
-
-out:
-	return err;
-}
-
 static void mipspmu_event_update(struct perf_event *event,
 			struct hw_perf_event *hwc,
 			int idx)
@@ -231,32 +196,90 @@ again:
 	return;
 }
 
-static void mipspmu_disable(struct perf_event *event)
+static void mipspmu_start(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (!mipspmu)
+		return;
+
+	if (flags & PERF_EF_RELOAD)
+		WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
+
+	hwc->state = 0;
+
+	/* Set the period for the event. */
+	mipspmu_event_set_period(event, hwc, hwc->idx);
+
+	/* Enable the event. */
+	mipspmu->enable_event(hwc, hwc->idx);
+}
+
+static void mipspmu_stop(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (!mipspmu)
+		return;
+
+	if (!(hwc->state & PERF_HES_STOPPED)) {
+		/* We are working on a local event. */
+		mipspmu->disable_event(hwc->idx);
+		barrier();
+		mipspmu_event_update(event, hwc, hwc->idx);
+		hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
+	}
+}
+
+static int mipspmu_add(struct perf_event *event, int flags)
 {
 	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
 	struct hw_perf_event *hwc = &event->hw;
-	int idx = hwc->idx;
+	int idx;
+	int err = 0;
 
+	perf_pmu_disable(event->pmu);
 
-	WARN_ON(idx < 0 || idx >= mipspmu->num_counters);
+	/* To look for a free counter for this event. */
+	idx = mipspmu->alloc_counter(cpuc, hwc);
+	if (idx < 0) {
+		err = idx;
+		goto out;
+	}
 
-	/* We are working on a local event. */
+	/*
+	 * If there is an event in the counter we are going to use then
+	 * make sure it is disabled.
+	 */
+	event->hw.idx = idx;
 	mipspmu->disable_event(idx);
+	cpuc->events[idx] = event;
 
-	barrier();
-
-	mipspmu_event_update(event, hwc, idx);
-	cpuc->events[idx] = NULL;
-	clear_bit(idx, cpuc->used_mask);
+	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+	if (flags & PERF_EF_START)
+		mipspmu_start(event, PERF_EF_RELOAD);
 
+	/* Propagate our changes to the userspace mapping. */
 	perf_event_update_userpage(event);
+
+out:
+	perf_pmu_enable(event->pmu);
+	return err;
 }
 
-static void mipspmu_unthrottle(struct perf_event *event)
+static void mipspmu_del(struct perf_event *event, int flags)
 {
+	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
 	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
 
-	mipspmu->enable_event(hwc, hwc->idx);
+	WARN_ON(idx < 0 || idx >= mipspmu->num_counters);
+
+	mipspmu_stop(event, PERF_EF_UPDATE);
+	cpuc->events[idx] = NULL;
+	clear_bit(idx, cpuc->used_mask);
+
+	perf_event_update_userpage(event);
 }
 
 static void mipspmu_read(struct perf_event *event)
@@ -270,12 +293,17 @@ static void mipspmu_read(struct perf_event *event)
 	mipspmu_event_update(event, hwc, hwc->idx);
 }
 
-static struct pmu pmu = {
-	.enable		= mipspmu_enable,
-	.disable	= mipspmu_disable,
-	.unthrottle	= mipspmu_unthrottle,
-	.read		= mipspmu_read,
-};
+static void mipspmu_enable(struct pmu *pmu)
+{
+	if (mipspmu)
+		mipspmu->start();
+}
+
+static void mipspmu_disable(struct pmu *pmu)
+{
+	if (mipspmu)
+		mipspmu->stop();
+}
 
 static atomic_t active_events = ATOMIC_INIT(0);
 static DEFINE_MUTEX(pmu_reserve_mutex);
@@ -318,6 +346,82 @@ static void mipspmu_free_irq(void)
 		perf_irq = save_perf_irq;
 }
 
+/*
+ * mipsxx/rm9000/loongson2 have different performance counters, they have
+ * specific low-level init routines.
+ */
+static void reset_counters(void *arg);
+static int __hw_perf_event_init(struct perf_event *event);
+
+static void hw_perf_event_destroy(struct perf_event *event)
+{
+	if (atomic_dec_and_mutex_lock(&active_events,
+				&pmu_reserve_mutex)) {
+		/*
+		 * We must not call the destroy function with interrupts
+		 * disabled.
+		 */
+		on_each_cpu(reset_counters,
+			(void *)(long)mipspmu->num_counters, 1);
+		mipspmu_free_irq();
+		mutex_unlock(&pmu_reserve_mutex);
+	}
+}
+
+static int mipspmu_event_init(struct perf_event *event)
+{
+	int err = 0;
+
+	switch (event->attr.type) {
+	case PERF_TYPE_RAW:
+	case PERF_TYPE_HARDWARE:
+	case PERF_TYPE_HW_CACHE:
+		break;
+
+	default:
+		return -ENOENT;
+	}
+
+	if (!mipspmu || event->cpu >= nr_cpumask_bits ||
+		(event->cpu >= 0 && !cpu_online(event->cpu)))
+		return -ENODEV;
+
+	if (!atomic_inc_not_zero(&active_events)) {
+		if (atomic_read(&active_events) > MIPS_MAX_HWEVENTS) {
+			atomic_dec(&active_events);
+			return -ENOSPC;
+		}
+
+		mutex_lock(&pmu_reserve_mutex);
+		if (atomic_read(&active_events) == 0)
+			err = mipspmu_get_irq();
+
+		if (!err)
+			atomic_inc(&active_events);
+		mutex_unlock(&pmu_reserve_mutex);
+	}
+
+	if (err)
+		return err;
+
+	err = __hw_perf_event_init(event);
+	if (err)
+		hw_perf_event_destroy(event);
+
+	return err;
+}
+
+static struct pmu pmu = {
+	.pmu_enable	= mipspmu_enable,
+	.pmu_disable	= mipspmu_disable,
+	.event_init	= mipspmu_event_init,
+	.add		= mipspmu_add,
+	.del		= mipspmu_del,
+	.start		= mipspmu_start,
+	.stop		= mipspmu_stop,
+	.read		= mipspmu_read,
+};
+
 static inline unsigned int
 mipspmu_perf_event_encode(const struct mips_perf_event *pev)
 {
@@ -409,73 +513,6 @@ static int validate_group(struct perf_event *event)
 	return 0;
 }
 
-/*
- * mipsxx/rm9000/loongson2 have different performance counters, they have
- * specific low-level init routines.
- */
-static void reset_counters(void *arg);
-static int __hw_perf_event_init(struct perf_event *event);
-
-static void hw_perf_event_destroy(struct perf_event *event)
-{
-	if (atomic_dec_and_mutex_lock(&active_events,
-				&pmu_reserve_mutex)) {
-		/*
-		 * We must not call the destroy function with interrupts
-		 * disabled.
-		 */
-		on_each_cpu(reset_counters,
-			(void *)(long)mipspmu->num_counters, 1);
-		mipspmu_free_irq();
-		mutex_unlock(&pmu_reserve_mutex);
-	}
-}
-
-const struct pmu *hw_perf_event_init(struct perf_event *event)
-{
-	int err = 0;
-
-	if (!mipspmu || event->cpu >= nr_cpumask_bits ||
-		(event->cpu >= 0 && !cpu_online(event->cpu)))
-		return ERR_PTR(-ENODEV);
-
-	if (!atomic_inc_not_zero(&active_events)) {
-		if (atomic_read(&active_events) > MIPS_MAX_HWEVENTS) {
-			atomic_dec(&active_events);
-			return ERR_PTR(-ENOSPC);
-		}
-
-		mutex_lock(&pmu_reserve_mutex);
-		if (atomic_read(&active_events) == 0)
-			err = mipspmu_get_irq();
-
-		if (!err)
-			atomic_inc(&active_events);
-		mutex_unlock(&pmu_reserve_mutex);
-	}
-
-	if (err)
-		return ERR_PTR(err);
-
-	err = __hw_perf_event_init(event);
-	if (err)
-		hw_perf_event_destroy(event);
-
-	return err ? ERR_PTR(err) : &pmu;
-}
-
-void hw_perf_enable(void)
-{
-	if (mipspmu)
-		mipspmu->start();
-}
-
-void hw_perf_disable(void)
-{
-	if (mipspmu)
-		mipspmu->stop();
-}
-
 /* This is needed by specific irq handlers in perf_event_*.c */
 static void
 handle_associated_event(struct cpu_hw_events *cpuc,
diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index fa00edc..c9406d6 100644
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/arch/mips/kernel/perf_event_mipsxx.c
@@ -1045,6 +1045,8 @@ init_hw_perf_events(void)
 			"CPU, irq %d%s\n", mipspmu->name, counters, irq,
 			irq < 0 ? " (share with timer interrupt)" : "");
 
+	perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
+
 	return 0;
 }
 early_initcall(init_hw_perf_events);
-- 
1.7.1

[PATCH v4 3/5] MIPS/Perf-events: Fix event check in validate_event()

[Deng-Cheng Zhu]

Ignore events that are in off/error state or belong to a different PMU.

This patch originates from the following commit for ARM by Will Deacon:

- 65b4711ff513767341aa1915c822de6ec0de65cb
    ARM: 6352/1: perf: fix event validation

    The validate_event function in the ARM perf events backend has the
    following problems:

    1.) Events that are disabled count towards the cost.
    2.) Events associated with other PMUs [for example, software events or
        breakpoints] do not count towards the cost, but do fail validation,
        causing the group to fail.

    This patch changes validate_event so that it ignores events in the
    PERF_EVENT_STATE_OFF state or that are scheduled for other PMUs.

Changes:
v4 - v3:
o None
v3 - v2:
o Keep all mentioned commits in the form of number + title + original
summary + (MIPS specific info when needed).
v2 - v1:
o Corrected the return value of the event check in validate_event().

Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
---
 arch/mips/kernel/perf_event.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
index 1ee44a3..3d55761 100644
--- a/arch/mips/kernel/perf_event.c
+++ b/arch/mips/kernel/perf_event.c
@@ -486,8 +486,9 @@ static int validate_event(struct cpu_hw_events *cpuc,
 {
 	struct hw_perf_event fake_hwc = event->hw;
 
-	if (event->pmu && event->pmu != &pmu)
-		return 0;
+	/* Allow mixed event group. So return 1 to pass validation. */
+	if (event->pmu != &pmu || event->state <= PERF_EVENT_STATE_OFF)
+		return 1;
 
 	return mipspmu->alloc_counter(cpuc, &fake_hwc) >= 0;
 }
-- 
1.7.1

Re: [PATCH v4 3/5] MIPS/Perf-events: Fix event check in validate_event()

[Sergei Shtylyov]

Hello.

On 21-01-2011 11:19, Deng-Cheng Zhu wrote:

> Ignore events that are in off/error state or belong to a different PMU.

> This patch originates from the following commit for ARM by Will Deacon:

> - 65b4711ff513767341aa1915c822de6ec0de65cb
>      ARM: 6352/1: perf: fix event validation

>      The validate_event function in the ARM perf events backend has the
>      following problems:

>      1.) Events that are disabled count towards the cost.
>      2.) Events associated with other PMUs [for example, software events or
>          breakpoints] do not count towards the cost, but do fail validation,
>          causing the group to fail.

>      This patch changes validate_event so that it ignores events in the
>      PERF_EVENT_STATE_OFF state or that are scheduled for other PMUs.

> Changes:
> v4 - v3:
> o None
> v3 - v2:
> o Keep all mentioned commits in the form of number + title + original
> summary + (MIPS specific info when needed).
> v2 - v1:
> o Corrected the return value of the event check in validate_event().

    The patch changes should follow the --- tearline, not precede it.

> Acked-by: Will Deacon<will.deacon@arm.com>
> Acked-by: David Daney<ddaney@caviumnetworks.com>
> Signed-off-by: Deng-Cheng Zhu<dengcheng.zhu@gmail.com>
> ---

WBR, Sergei

Re: [PATCH v4 3/5] MIPS/Perf-events: Fix event check in validate_event()

[Deng-Cheng Zhu]

Thanks. The patch set was resent.


Deng-Cheng

2011/1/21 Sergei Shtylyov <sshtylyov@mvista.com>:
> Hello.
>
> On 21-01-2011 11:19, Deng-Cheng Zhu wrote:
>
>> Ignore events that are in off/error state or belong to a different PMU.
>
>> This patch originates from the following commit for ARM by Will Deacon:
>
>> - 65b4711ff513767341aa1915c822de6ec0de65cb
>>     ARM: 6352/1: perf: fix event validation
>
>>     The validate_event function in the ARM perf events backend has the
>>     following problems:
>
>>     1.) Events that are disabled count towards the cost.
>>     2.) Events associated with other PMUs [for example, software events or
>>         breakpoints] do not count towards the cost, but do fail
>> validation,
>>         causing the group to fail.
>
>>     This patch changes validate_event so that it ignores events in the
>>     PERF_EVENT_STATE_OFF state or that are scheduled for other PMUs.
>
>> Changes:
>> v4 - v3:
>> o None
>> v3 - v2:
>> o Keep all mentioned commits in the form of number + title + original
>> summary + (MIPS specific info when needed).
>> v2 - v1:
>> o Corrected the return value of the event check in validate_event().
>
>   The patch changes should follow the --- tearline, not precede it.
>
>> Acked-by: Will Deacon<will.deacon@arm.com>
>> Acked-by: David Daney<ddaney@caviumnetworks.com>
>> Signed-off-by: Deng-Cheng Zhu<dengcheng.zhu@gmail.com>
>> ---
>
> WBR, Sergei
>

[PATCH v4 4/5] MIPS/Perf-events: Work with the new callchain interface

[Deng-Cheng Zhu]

This is the MIPS part of the following commits by Frederic Weisbecker:

- f72c1a931e311bb7780fee19e41a89ac42cab50e
    perf: Factorize callchain context handling

    Store the kernel and user contexts from the generic layer instead
    of archs, this gathers some repetitive code.

- 56962b4449af34070bb1994621ef4f0265eed4d8
    perf: Generalize some arch callchain code

    - Most archs use one callchain buffer per cpu, except x86 that needs
      to deal with NMIs. Provide a default perf_callchain_buffer()
      implementation that x86 overrides.

    - Centralize all the kernel/user regs handling and invoke new arch
      handlers from there: perf_callchain_user() / perf_callchain_kernel()
      That avoid all the user_mode(), current->mm checks and so...

    - Invert some parameters in perf_callchain_*() helpers: entry to the
      left, regs to the right, following the traditional (dst, src).

- 70791ce9ba68a5921c9905ef05d23f62a90bc10c
    perf: Generalize callchain_store()

    callchain_store() is the same on every archs, inline it in
    perf_event.h and rename it to perf_callchain_store() to avoid
    any collision.

    This removes repetitive code.

- c1a65932fd7216fdc9a0db8bbffe1d47842f862c
    perf: Drop unappropriate tests on arch callchains

    Drop the TASK_RUNNING test on user tasks for callchains as
    this check doesn't seem to make any sense.

    Also remove the tests for !current that is not supposed to
    happen and current->pid as this should be handled at the
    generic level, with exclude_idle attribute.

Changes:
v4 - v3:
o None
v3 - v2:
o Keep all mentioned commits in the form of number + title + original
summary + (MIPS specific info when needed).
v2 - v1:
o None

Reported-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
---
 arch/mips/kernel/perf_event.c |   63 ++++-------------------------------------
 1 files changed, 6 insertions(+), 57 deletions(-)

diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
index 3d55761..8f7d2f8 100644
--- a/arch/mips/kernel/perf_event.c
+++ b/arch/mips/kernel/perf_event.c
@@ -534,21 +534,13 @@ handle_associated_event(struct cpu_hw_events *cpuc,
 #include "perf_event_mipsxx.c"
 
 /* Callchain handling code. */
-static inline void
-callchain_store(struct perf_callchain_entry *entry,
-		u64 ip)
-{
-	if (entry->nr < PERF_MAX_STACK_DEPTH)
-		entry->ip[entry->nr++] = ip;
-}
 
 /*
  * Leave userspace callchain empty for now. When we find a way to trace
  * the user stack callchains, we add here.
  */
-static void
-perf_callchain_user(struct pt_regs *regs,
-		    struct perf_callchain_entry *entry)
+void perf_callchain_user(struct perf_callchain_entry *entry,
+		    struct pt_regs *regs)
 {
 }
 
@@ -561,23 +553,21 @@ static void save_raw_perf_callchain(struct perf_callchain_entry *entry,
 	while (!kstack_end(sp)) {
 		addr = *sp++;
 		if (__kernel_text_address(addr)) {
-			callchain_store(entry, addr);
+			perf_callchain_store(entry, addr);
 			if (entry->nr >= PERF_MAX_STACK_DEPTH)
 				break;
 		}
 	}
 }
 
-static void
-perf_callchain_kernel(struct pt_regs *regs,
-		      struct perf_callchain_entry *entry)
+void perf_callchain_kernel(struct perf_callchain_entry *entry,
+		      struct pt_regs *regs)
 {
 	unsigned long sp = regs->regs[29];
 #ifdef CONFIG_KALLSYMS
 	unsigned long ra = regs->regs[31];
 	unsigned long pc = regs->cp0_epc;
 
-	callchain_store(entry, PERF_CONTEXT_KERNEL);
 	if (raw_show_trace || !__kernel_text_address(pc)) {
 		unsigned long stack_page =
 			(unsigned long)task_stack_page(current);
@@ -587,53 +577,12 @@ perf_callchain_kernel(struct pt_regs *regs,
 		return;
 	}
 	do {
-		callchain_store(entry, pc);
+		perf_callchain_store(entry, pc);
 		if (entry->nr >= PERF_MAX_STACK_DEPTH)
 			break;
 		pc = unwind_stack(current, &sp, pc, &ra);
 	} while (pc);
 #else
-	callchain_store(entry, PERF_CONTEXT_KERNEL);
 	save_raw_perf_callchain(entry, sp);
 #endif
 }
-
-static void
-perf_do_callchain(struct pt_regs *regs,
-		  struct perf_callchain_entry *entry)
-{
-	int is_user;
-
-	if (!regs)
-		return;
-
-	is_user = user_mode(regs);
-
-	if (!current || !current->pid)
-		return;
-
-	if (is_user && current->state != TASK_RUNNING)
-		return;
-
-	if (!is_user) {
-		perf_callchain_kernel(regs, entry);
-		if (current->mm)
-			regs = task_pt_regs(current);
-		else
-			regs = NULL;
-	}
-	if (regs)
-		perf_callchain_user(regs, entry);
-}
-
-static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_irq_entry);
-
-struct perf_callchain_entry *
-perf_callchain(struct pt_regs *regs)
-{
-	struct perf_callchain_entry *entry = &__get_cpu_var(pmc_irq_entry);
-
-	entry->nr = 0;
-	perf_do_callchain(regs, entry);
-	return entry;
-}
-- 
1.7.1

[PATCH v4 5/5] MIPS/Perf-events: Use unsigned delta for right shift in event update

[Deng-Cheng Zhu]

Leverage the commit for ARM by Will Deacon:

- 446a5a8b1eb91a6990e5c8fe29f14e7a95b69132
    ARM: 6205/1: perf: ensure counter delta is treated as unsigned

    Hardware performance counters on ARM are 32-bits wide but atomic64_t
    variables are used to represent counter data in the hw_perf_event structure.

    The armpmu_event_update function right-shifts a signed 64-bit delta variable
    and adds the result to the event count. This can lead to shifting in sign-bits
    if the MSB of the 32-bit counter value is set. This results in perf output
    such as:

     Performance counter stats for 'sleep 20':

     18446744073460670464  cycles             <-- 0xFFFFFFFFF12A6000
            7783773  instructions             #      0.000 IPC
                465  context-switches
                161  page-faults
            1172393  branches

       20.154242147  seconds time elapsed

    This patch ensures that the delta value is treated as unsigned so that the
    right shift sets the upper bits to zero.

Changes:
v4 - v3:
o None
v3 - v2:
o Keep all mentioned commits in the form of number + title + original
summary + (MIPS specific info when needed).
v2 - v1:
o None

Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
---
 arch/mips/kernel/perf_event.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
index 8f7d2f8..a824485 100644
--- a/arch/mips/kernel/perf_event.c
+++ b/arch/mips/kernel/perf_event.c
@@ -169,7 +169,7 @@ static void mipspmu_event_update(struct perf_event *event,
 	unsigned long flags;
 	int shift = 64 - TOTAL_BITS;
 	s64 prev_raw_count, new_raw_count;
-	s64 delta;
+	u64 delta;
 
 again:
 	prev_raw_count = local64_read(&hwc->prev_count);
-- 
1.7.1