[PATCH] coresight replicator: set default y after Kconfig rename

[PATCH] coresight replicator: set default y after Kconfig rename

[Kim Phillips]

Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
replicator naming") changed the Kconfig symbol name from
QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
was being set in my juno build script, which left the new symbol unset,
causing the following unexpected grief:

 # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
 ..<snip>..
 sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
 mmap size 528384B
 AUX area mmap length 4194304
 perf event ring buffer mmapped per cpu
 failed to mmap AUX area
 failed to mmap with 12 (Cannot allocate memory)

Make it default y to help not surprise unsuspecting users.

Fixes: 1c8859848dbb ("coresight replicator: Cleanup programmable replicator naming")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Kim Phillips <kim.phillips@arm.com>
---
 drivers/hwtracing/coresight/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index ef9cb3c164e1..b94bbd95efa6 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -73,6 +73,7 @@ config CORESIGHT_SOURCE_ETM4X
 config CORESIGHT_DYNAMIC_REPLICATOR
 	bool "CoreSight Programmable Replicator driver"
 	depends on CORESIGHT_LINKS_AND_SINKS
+	default y
 	help
 	  This enables support for dynamic CoreSight replicator link driver.
 	  The programmable ATB replicator allows independent filtering of the
-- 
2.16.1

[PATCH] coresight replicator: set default y after Kconfig rename

[Mathieu Poirier]

On 7 February 2018 at 14:03, Kim Phillips <kim.phillips@arm.com> wrote:
> Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
> replicator naming") changed the Kconfig symbol name from
> QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
> was being set in my juno build script, which left the new symbol unset,
> causing the following unexpected grief:
>
>  # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
>  ..<snip>..
>  sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
>  mmap size 528384B
>  AUX area mmap length 4194304
>  perf event ring buffer mmapped per cpu
>  failed to mmap AUX area
>  failed to mmap with 12 (Cannot allocate memory)
>
> Make it default y to help not surprise unsuspecting users.
>
> Fixes: 1c8859848dbb ("coresight replicator: Cleanup programmable replicator naming")
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> ---
>  drivers/hwtracing/coresight/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> index ef9cb3c164e1..b94bbd95efa6 100644
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig
> @@ -73,6 +73,7 @@ config CORESIGHT_SOURCE_ETM4X
>  config CORESIGHT_DYNAMIC_REPLICATOR
>         bool "CoreSight Programmable Replicator driver"
>         depends on CORESIGHT_LINKS_AND_SINKS
> +       default y
>         help
>           This enables support for dynamic CoreSight replicator link driver.
>           The programmable ATB replicator allows independent filtering of the

As I said before don't see why it needs to be treated differently than other CS
blocks - intelligent replicators show up on the AMBA bus and need to
be declared in the DT.  As such people are expected to enable the proper
option.

Mathieu

> --
> 2.16.1
>

[PATCH] coresight replicator: set default y after Kconfig rename

[Kim Phillips]

On Thu, 8 Feb 2018 08:59:30 -0700
Mathieu Poirier <mathieu.poirier@linaro.org> wrote:

> On 7 February 2018 at 14:03, Kim Phillips <kim.phillips@arm.com> wrote:
> > Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
> > replicator naming") changed the Kconfig symbol name from
> > QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
> > was being set in my juno build script, which left the new symbol unset,
> > causing the following unexpected grief:
> >
> >  # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
> >  ..<snip>..
> >  sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
> >  mmap size 528384B
> >  AUX area mmap length 4194304
> >  perf event ring buffer mmapped per cpu
> >  failed to mmap AUX area
> >  failed to mmap with 12 (Cannot allocate memory)
> >
> > Make it default y to help not surprise unsuspecting users.
> >
> > Fixes: 1c8859848dbb ("coresight replicator: Cleanup programmable replicator naming")
> > Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> > Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> > ---
> >  drivers/hwtracing/coresight/Kconfig | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> > index ef9cb3c164e1..b94bbd95efa6 100644
> > --- a/drivers/hwtracing/coresight/Kconfig
> > +++ b/drivers/hwtracing/coresight/Kconfig
> > @@ -73,6 +73,7 @@ config CORESIGHT_SOURCE_ETM4X
> >  config CORESIGHT_DYNAMIC_REPLICATOR
> >         bool "CoreSight Programmable Replicator driver"
> >         depends on CORESIGHT_LINKS_AND_SINKS
> > +       default y
> >         help
> >           This enables support for dynamic CoreSight replicator link driver.
> >           The programmable ATB replicator allows independent filtering of the
> 
> As I said before don't see why it needs to be treated differently than other CS
> blocks

I don't think it does either, but this one is special since it recently
underwent a rename, which breaks its users that were setting the old
name in their config builds.  The default y keeps it set in those
cases, thereby discontinuing any such regression.

> - intelligent replicators show up on the AMBA bus and need to
> be declared in the DT.  As such people are expected to enable the proper
> option.

The driver should only run given a replicator in the device tree; if
that's not the case, then that's another problem, and orthogonal to
this one.

Kim

[PATCH] coresight replicator: set default y after Kconfig rename

[Suzuki K Poulose]

On 08/02/18 17:22, Kim Phillips wrote:
> On Thu, 8 Feb 2018 08:59:30 -0700
> Mathieu Poirier <mathieu.poirier@linaro.org> wrote:
> 
>> On 7 February 2018 at 14:03, Kim Phillips <kim.phillips@arm.com> wrote:
>>> Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
>>> replicator naming") changed the Kconfig symbol name from
>>> QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
>>> was being set in my juno build script, which left the new symbol unset,
>>> causing the following unexpected grief:
>>>
>>>   # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
>>>   ..<snip>..
>>>   sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
>>>   mmap size 528384B
>>>   AUX area mmap length 4194304
>>>   perf event ring buffer mmapped per cpu
>>>   failed to mmap AUX area
>>>   failed to mmap with 12 (Cannot allocate memory)
>>>
>>> Make it default y to help not surprise unsuspecting users.
>>>
>>> Fixes: 1c8859848dbb ("coresight replicator: Cleanup programmable replicator naming")
>>> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
>>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
>>> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
>>> ---
>>>   drivers/hwtracing/coresight/Kconfig | 1 +
>>>   1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
>>> index ef9cb3c164e1..b94bbd95efa6 100644
>>> --- a/drivers/hwtracing/coresight/Kconfig
>>> +++ b/drivers/hwtracing/coresight/Kconfig
>>> @@ -73,6 +73,7 @@ config CORESIGHT_SOURCE_ETM4X
>>>   config CORESIGHT_DYNAMIC_REPLICATOR
>>>          bool "CoreSight Programmable Replicator driver"
>>>          depends on CORESIGHT_LINKS_AND_SINKS
>>> +       default y
>>>          help
>>>            This enables support for dynamic CoreSight replicator link driver.
>>>            The programmable ATB replicator allows independent filtering of the
>>
>> As I said before don't see why it needs to be treated differently than other CS
>> blocks
> 
> I don't think it does either, but this one is special since it recently
> underwent a rename, which breaks its users that were setting the old
> name in their config builds.  The default y keeps it set in those
> cases, thereby discontinuing any such regression.

I don't think the kernel CONFIG symbols are part of the kernel ABI. So,
unfortunately the users have to take care of making sure they select what
they need.

Suzuki

[PATCH] coresight replicator: set default y after Kconfig rename

[Kim Phillips]

On Thu, 8 Feb 2018 18:01:21 +0000
Suzuki K Poulose <Suzuki.Poulose@arm.com> wrote:

> On 08/02/18 17:22, Kim Phillips wrote:
> > On Thu, 8 Feb 2018 08:59:30 -0700
> > Mathieu Poirier <mathieu.poirier@linaro.org> wrote:
> > 
> >> On 7 February 2018 at 14:03, Kim Phillips <kim.phillips@arm.com> wrote:
> >>> Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
> >>> replicator naming") changed the Kconfig symbol name from
> >>> QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
> >>> was being set in my juno build script, which left the new symbol unset,
> >>> causing the following unexpected grief:
> >>>
> >>>   # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
> >>>   ..<snip>..
> >>>   sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
> >>>   mmap size 528384B
> >>>   AUX area mmap length 4194304
> >>>   perf event ring buffer mmapped per cpu
> >>>   failed to mmap AUX area
> >>>   failed to mmap with 12 (Cannot allocate memory)
> >>>
> >>> Make it default y to help not surprise unsuspecting users.
> >>>
> >>> Fixes: 1c8859848dbb ("coresight replicator: Cleanup programmable replicator naming")
> >>> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> >>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> >>> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> >>> ---
> >>>   drivers/hwtracing/coresight/Kconfig | 1 +
> >>>   1 file changed, 1 insertion(+)
> >>>
> >>> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> >>> index ef9cb3c164e1..b94bbd95efa6 100644
> >>> --- a/drivers/hwtracing/coresight/Kconfig
> >>> +++ b/drivers/hwtracing/coresight/Kconfig
> >>> @@ -73,6 +73,7 @@ config CORESIGHT_SOURCE_ETM4X
> >>>   config CORESIGHT_DYNAMIC_REPLICATOR
> >>>          bool "CoreSight Programmable Replicator driver"
> >>>          depends on CORESIGHT_LINKS_AND_SINKS
> >>> +       default y
> >>>          help
> >>>            This enables support for dynamic CoreSight replicator link driver.
> >>>            The programmable ATB replicator allows independent filtering of the
> >>
> >> As I said before don't see why it needs to be treated differently than other CS
> >> blocks
> > 
> > I don't think it does either, but this one is special since it recently
> > underwent a rename, which breaks its users that were setting the old
> > name in their config builds.  The default y keeps it set in those
> > cases, thereby discontinuing any such regression.
> 
> I don't think the kernel CONFIG symbols are part of the kernel ABI. So,
> unfortunately the users have to take care of making sure they select what
> they need.

Right, sorry, I wan't referring to a kernel ABI regression :)  Think of
it as just trying to make Coresight easier to configure, and in this
particular case, given Coresight Kconfig symbol name volatility.

Kim

[PATCH] coresight replicator: set default y after Kconfig rename

[Robin Murphy]

On 07/02/18 21:03, Kim Phillips wrote:
> Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
> replicator naming") changed the Kconfig symbol name from
> QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
> was being set in my juno build script, which left the new symbol unset,
> causing the following unexpected grief:
> 
>   # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
>   ..<snip>..
>   sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
>   mmap size 528384B
>   AUX area mmap length 4194304
>   perf event ring buffer mmapped per cpu
>   failed to mmap AUX area
>   failed to mmap with 12 (Cannot allocate memory)
> 
> Make it default y to help not surprise unsuspecting users.

How many users are there relying on your Juno build script? :P

> Fixes: 1c8859848dbb ("coresight replicator: Cleanup programmable replicator naming")

Before that commit, CORESIGHT_QCOM_REPLICATOR was not "default y", nor 
selected by any in-tree configs, so whatever the problem may be this is 
clearly not the correct fix.

> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> ---
>   drivers/hwtracing/coresight/Kconfig | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> index ef9cb3c164e1..b94bbd95efa6 100644
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig
> @@ -73,6 +73,7 @@ config CORESIGHT_SOURCE_ETM4X
>   config CORESIGHT_DYNAMIC_REPLICATOR
>   	bool "CoreSight Programmable Replicator driver"
>   	depends on CORESIGHT_LINKS_AND_SINKS
> +	default y

CORESIGHT_LINKS_AND_SINKS is "default n" (as indeed is CORESIGHT), and 
not selected by any defconfigs, so in general this doesn't really help 
anyway.

Robin.

>   	help
>   	  This enables support for dynamic CoreSight replicator link driver.
>   	  The programmable ATB replicator allows independent filtering of the
> 

[PATCH] coresight replicator: set default y after Kconfig rename

[Kim Phillips]

On Thu, 8 Feb 2018 16:13:16 +0000
Robin Murphy <robin.murphy@arm.com> wrote:

> On 07/02/18 21:03, Kim Phillips wrote:
> > Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
> > replicator naming") changed the Kconfig symbol name from
> > QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
> > was being set in my juno build script, which left the new symbol unset,
> > causing the following unexpected grief:
> > 
> >   # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
> >   ..<snip>..
> >   sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
> >   mmap size 528384B
> >   AUX area mmap length 4194304
> >   perf event ring buffer mmapped per cpu
> >   failed to mmap AUX area
> >   failed to mmap with 12 (Cannot allocate memory)
> > 
> > Make it default y to help not surprise unsuspecting users.
> 
> How many users are there relying on your Juno build script? :P

This shouldn't be that uncommon for coresight users:

make defconfig
scripts/config -e CONFIG_CORESIGHT
scripts/config -e CONFIG_CORESIGHT_LINK_AND_SINK_TMC
scripts/config -e CONFIG_CORESIGHT_SINK_TPIU
scripts/config -e CONFIG_CORESIGHT_SINK_ETBV10
scripts/config -e CONFIG_CORESIGHT_LINKS_AND_SINKS
scripts/config -e CONFIG_CORESIGHT_SOURCE_ETM3X
scripts/config -e CONFIG_CORESIGHT_SOURCE_ETM4X
#scripts/config -e CONFIG_CORESIGHT_QCOM_REPLICATOR
scripts/config -e CONFIG_CORESIGHT_DYNAMIC_REPLICATOR
scripts/config -e CONFIG_CORESIGHT_STM
scripts/config -e CONFIG_CORESIGHT_CPU_DEBUG

FWIW, Mathieu - who helped me track the cannot allocate memory problem
down to this config symbol - has also benn caught by this issue.

> > Fixes: 1c8859848dbb ("coresight replicator: Cleanup programmable replicator naming")
> 
> Before that commit, CORESIGHT_QCOM_REPLICATOR was not "default y", nor 
> selected by any in-tree configs, so whatever the problem may be this is 
> clearly not the correct fix.

Well, there's only one defconfig for arm64.  I don't know why it
doesn't set CORESIGHT, but you're right, this is taking the build fix
one step further to facilitate user coresight configuration.  I can
change the patch to make the change to the arm64 defconfig, but I still
believe CORESIGHT_DYNAMIC_REPLICATOR should be default=y, and the
defconfig just set CORESIGHT.

> > Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> > Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> > ---
> >   drivers/hwtracing/coresight/Kconfig | 1 +
> >   1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> > index ef9cb3c164e1..b94bbd95efa6 100644
> > --- a/drivers/hwtracing/coresight/Kconfig
> > +++ b/drivers/hwtracing/coresight/Kconfig
> > @@ -73,6 +73,7 @@ config CORESIGHT_SOURCE_ETM4X
> >   config CORESIGHT_DYNAMIC_REPLICATOR
> >   	bool "CoreSight Programmable Replicator driver"
> >   	depends on CORESIGHT_LINKS_AND_SINKS
> > +	default y
> 
> CORESIGHT_LINKS_AND_SINKS is "default n" (as indeed is CORESIGHT), and 
> not selected by any defconfigs, so in general this doesn't really help 
> anyway.

Yeah, CORESIGHT_LINKS_AND_SINKS should probably be default y too.

Kim

[PATCH] coresight replicator: set default y after Kconfig rename

[Randy Dunlap]

On 02/08/2018 11:23 AM, Kim Phillips wrote:
> On Thu, 8 Feb 2018 16:13:16 +0000
> Robin Murphy <robin.murphy@arm.com> wrote:
> 
>> On 07/02/18 21:03, Kim Phillips wrote:
>>> Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
>>> replicator naming") changed the Kconfig symbol name from
>>> QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
>>> was being set in my juno build script, which left the new symbol unset,
>>> causing the following unexpected grief:
>>>
>>>   # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
>>>   ..<snip>..
>>>   sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
>>>   mmap size 528384B
>>>   AUX area mmap length 4194304
>>>   perf event ring buffer mmapped per cpu
>>>   failed to mmap AUX area
>>>   failed to mmap with 12 (Cannot allocate memory)
>>>
>>> Make it default y to help not surprise unsuspecting users.
>>
>> How many users are there relying on your Juno build script? :P
> 
> This shouldn't be that uncommon for coresight users:
> 
> make defconfig
> scripts/config -e CONFIG_CORESIGHT
> scripts/config -e CONFIG_CORESIGHT_LINK_AND_SINK_TMC
> scripts/config -e CONFIG_CORESIGHT_SINK_TPIU
> scripts/config -e CONFIG_CORESIGHT_SINK_ETBV10
> scripts/config -e CONFIG_CORESIGHT_LINKS_AND_SINKS
> scripts/config -e CONFIG_CORESIGHT_SOURCE_ETM3X
> scripts/config -e CONFIG_CORESIGHT_SOURCE_ETM4X
> #scripts/config -e CONFIG_CORESIGHT_QCOM_REPLICATOR
> scripts/config -e CONFIG_CORESIGHT_DYNAMIC_REPLICATOR
> scripts/config -e CONFIG_CORESIGHT_STM
> scripts/config -e CONFIG_CORESIGHT_CPU_DEBUG
> 
> FWIW, Mathieu - who helped me track the cannot allocate memory problem
> down to this config symbol - has also benn caught by this issue.
> 
>>> Fixes: 1c8859848dbb ("coresight replicator: Cleanup programmable replicator naming")
>>
>> Before that commit, CORESIGHT_QCOM_REPLICATOR was not "default y", nor 
>> selected by any in-tree configs, so whatever the problem may be this is 
>> clearly not the correct fix.
> 
> Well, there's only one defconfig for arm64.  I don't know why it
> doesn't set CORESIGHT, but you're right, this is taking the build fix
> one step further to facilitate user coresight configuration.  I can
> change the patch to make the change to the arm64 defconfig, but I still
> believe CORESIGHT_DYNAMIC_REPLICATOR should be default=y, and the
> defconfig just set CORESIGHT.
> 
>>> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
>>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
>>> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
>>> ---
>>>   drivers/hwtracing/coresight/Kconfig | 1 +
>>>   1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
>>> index ef9cb3c164e1..b94bbd95efa6 100644
>>> --- a/drivers/hwtracing/coresight/Kconfig
>>> +++ b/drivers/hwtracing/coresight/Kconfig
>>> @@ -73,6 +73,7 @@ config CORESIGHT_SOURCE_ETM4X
>>>   config CORESIGHT_DYNAMIC_REPLICATOR
>>>   	bool "CoreSight Programmable Replicator driver"
>>>   	depends on CORESIGHT_LINKS_AND_SINKS
>>> +	default y
>>
>> CORESIGHT_LINKS_AND_SINKS is "default n" (as indeed is CORESIGHT), and 
>> not selected by any defconfigs, so in general this doesn't really help 
>> anyway.
> 
> Yeah, CORESIGHT_LINKS_AND_SINKS should probably be default y too.

Are they required for system operation?  If not, they should not default to y.

and if they are required, it seems odd that they are in drivers/hwtracing/.


-- 
~Randy

[PATCH] coresight replicator: set default y after Kconfig rename

[Kim Phillips]

On Thu, 8 Feb 2018 11:53:44 -0800
Randy Dunlap <rdunlap@infradead.org> wrote:

> On 02/08/2018 11:23 AM, Kim Phillips wrote:
> > On Thu, 8 Feb 2018 16:13:16 +0000
> > Robin Murphy <robin.murphy@arm.com> wrote:
> > 
> >> On 07/02/18 21:03, Kim Phillips wrote:
> >>> Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
> >>> replicator naming") changed the Kconfig symbol name from
> >>> QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
> >>> was being set in my juno build script, which left the new symbol unset,
> >>> causing the following unexpected grief:
> >>>
> >>>   # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
> >>>   ..<snip>..
> >>>   sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
> >>>   mmap size 528384B
> >>>   AUX area mmap length 4194304
> >>>   perf event ring buffer mmapped per cpu
> >>>   failed to mmap AUX area
> >>>   failed to mmap with 12 (Cannot allocate memory)
> >>>
> >>> Make it default y to help not surprise unsuspecting users.
> >>
> >> How many users are there relying on your Juno build script? :P
> > 
> > This shouldn't be that uncommon for coresight users:
> > 
> > make defconfig
> > scripts/config -e CONFIG_CORESIGHT
> > scripts/config -e CONFIG_CORESIGHT_LINK_AND_SINK_TMC
> > scripts/config -e CONFIG_CORESIGHT_SINK_TPIU
> > scripts/config -e CONFIG_CORESIGHT_SINK_ETBV10
> > scripts/config -e CONFIG_CORESIGHT_LINKS_AND_SINKS
> > scripts/config -e CONFIG_CORESIGHT_SOURCE_ETM3X
> > scripts/config -e CONFIG_CORESIGHT_SOURCE_ETM4X
> > #scripts/config -e CONFIG_CORESIGHT_QCOM_REPLICATOR
> > scripts/config -e CONFIG_CORESIGHT_DYNAMIC_REPLICATOR
> > scripts/config -e CONFIG_CORESIGHT_STM
> > scripts/config -e CONFIG_CORESIGHT_CPU_DEBUG
> > 
> > FWIW, Mathieu - who helped me track the cannot allocate memory problem
> > down to this config symbol - has also benn caught by this issue.
> > 
> >>> Fixes: 1c8859848dbb ("coresight replicator: Cleanup programmable replicator naming")
> >>
> >> Before that commit, CORESIGHT_QCOM_REPLICATOR was not "default y", nor 
> >> selected by any in-tree configs, so whatever the problem may be this is 
> >> clearly not the correct fix.
> > 
> > Well, there's only one defconfig for arm64.  I don't know why it
> > doesn't set CORESIGHT, but you're right, this is taking the build fix
> > one step further to facilitate user coresight configuration.  I can
> > change the patch to make the change to the arm64 defconfig, but I still
> > believe CORESIGHT_DYNAMIC_REPLICATOR should be default=y, and the
> > defconfig just set CORESIGHT.
> > 
> >>> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> >>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> >>> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> >>> ---
> >>>   drivers/hwtracing/coresight/Kconfig | 1 +
> >>>   1 file changed, 1 insertion(+)
> >>>
> >>> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> >>> index ef9cb3c164e1..b94bbd95efa6 100644
> >>> --- a/drivers/hwtracing/coresight/Kconfig
> >>> +++ b/drivers/hwtracing/coresight/Kconfig
> >>> @@ -73,6 +73,7 @@ config CORESIGHT_SOURCE_ETM4X
> >>>   config CORESIGHT_DYNAMIC_REPLICATOR
> >>>   	bool "CoreSight Programmable Replicator driver"
> >>>   	depends on CORESIGHT_LINKS_AND_SINKS
> >>> +	default y
> >>
> >> CORESIGHT_LINKS_AND_SINKS is "default n" (as indeed is CORESIGHT), and 
> >> not selected by any defconfigs, so in general this doesn't really help 
> >> anyway.
> > 
> > Yeah, CORESIGHT_LINKS_AND_SINKS should probably be default y too.
> 
> Are they required for system operation?  If not, they should not default to y.

They're not required for general purpose system operation: they're
protected by an if CORESIGHT.  All the other CORESIGHT symbols select
CORESIGHT_LINKS_AND_SINKS except CORESIGHT_CPU_DEBUG, which doesn't
need to be protected by the if CORESIGHT.

> and if they are required, it seems odd that they are in drivers/hwtracing/.

Right, they are required for tracing using the Coresight subsystem, not
general purpose system operation, so they can be 'default y' under 'if
CORESIGHT' protection.

Kim

[PATCH] coresight replicator: set default y after Kconfig rename

[Suzuki K Poulose]

On 07/02/18 21:03, Kim Phillips wrote:
> Commit 1c8859848dbb ("coresight replicator: Cleanup programmable
> replicator naming") changed the Kconfig symbol name from
> QCOM_REPLICATOR, which, whilst not in the single arm64 defconfig,
> was being set in my juno build script, which left the new symbol unset,
> causing the following unexpected grief:
> 
>   # ./perf record -vvv -C 0 -e cs_etm/@20070000.etr/ --per-thread true
>   ..<snip>..
>   sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 5
>   mmap size 528384B
>   AUX area mmap length 4194304
>   perf event ring buffer mmapped per cpu
>   failed to mmap AUX area
>   failed to mmap with 12 (Cannot allocate memory)
> 
> Make it default y to help not surprise unsuspecting users.

I think the best way to address this issue is to set the proper errno when
we fail to build a path, say -ENODEV, that could give us a better clue
on what is going wrong. Have you checked the dmesg to see if it complains
about "build path" failure ?

Cheers
Suzuki