The coresight drivers have absolutely no control over bind and unbind
operations triggered from sysfs. The operations simply can't be
cancelled or denied event when one or several tracing sessions are
under way.  Since the memory associated to individual device is
invariably freed, the end result is a kernel crash when the path from
source to sink is travelled again as demonstrated here[1].

One solution could be to keep track of all the path (i.e tracing
session) that get created and iterate through the elements of those path
looking for the coresight device that is being removed.  This proposition
doesn't scale well since there is no upper bound on the amount of
concurrent trace session that can be created.

With the above in mind, this patch prevent devices from being unbounded
from their driver by using the driver->suppress_bind_attr option.  That way
trace sessions can be managed without fearing to loose devices.

Since device can't be removed anymore the xyz_remove() functions found in
each driver is also removed.

[1]. http://www.spinics.net/lists/arm-kernel/msg474952.htmlReported-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

1. TRCRSCTLRn - Resource Selection Control Registers n=0~1 are reserved,
   we shouldn't access them.
2. The max number of 'n' here is defined in TRCIDR4.NUMRSPAIR whoes value
   indicates the number of resource selection *pairs*, and 0 indicates
   one resource selection pair, 1 indicates two pairs, and so on ...

So, the total number of resource selection control registers which we can
access is (TRCIDR4.NUMRSPAIR * 2)
Signed-off-by: NChunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Like ETTv3, ETMv4 also needs the similar modifications to support Context
ID tracing when PID namespace is enabled.
Signed-off-by: NChunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

'ctxid_val' array was used to store the value of ETM context ID comparator
which actually stores the process ID to be traced, so using 'ctxid_pid' as
its name instead make it easier to understand.

This patch also changes the ABI, it is normally not allowed, but
fortunately it is a testing ABI and very new for now. Nevertheless,
if you don't think it should be changed, we could always add an alias
for userspace.
Signed-off-by: NChunyan Zhang <zhang.chunyan@linaro.org>
Reviewed-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In commit 2e1cdfe1 ("coresight-etm4x:
Adding CoreSight ETM4x driver") this driver was added.

It uses module_amba_driver() to register itself with the system,
which is just an alias for module_driver.  This currently works by
relying on getting that via init.h but we are planning to move that
code[1] to module.h -- at which time this will fail to compile since
it does not include module.h currently, resulting in:

drivers/hwtracing/coresight/coresight-etm4x.c:2701:1: note: in expansion of macro ‘module_amba_driver’
 module_amba_driver(etm4x_driver);
 ^
include/linux/device.h:1296:1: error: type defaults to ‘int’ in declaration of ‘module_init’ [-Werror=implicit-int]
 module_init(__driver##_init); \
 ^

In the future, the amba support may want to create another alias that
uses builtin_driver[2] for cases like this which are using bool Kconfig
triggers, but for now we just fix the implicit include.

[1] https://lkml.kernel.org/r/1433276168-21550-1-git-send-email-paul.gortmaker@windriver.com
[2] https://lkml.kernel.org/r/1431287385-1526-1-git-send-email-paul.gortmaker@windriver.com

Cc: Pratik Patel <pratikp@codeaurora.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ETM ID registers contain valuable information about the capabilities
of the implementation and are very useful when configuring the device for
various trace scenarios.
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Having access to the ETMv4 management registers is very useful as they
give meaningful information on how the IP block has been configured at
synthesis time.
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding sysfs entries to access and configure specifics about the
virtual machine ID comparator functions.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding sysfs entries to access and configure specifics about the
context ID comparator functions.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding sysfs entries to control the selection of the resources the
trace unit will use as triggers to perform a trace run.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding sysfs entries related to the counter functionality, more
specifically to set, control and reload the counters.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding sysfs entries to access the sequencers related registers,
more specifically the sequencer state, the sequencer state
transition and the sequencer reset control registers.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding sysfs entries to control the various mode the address comparator
registers can enact, i.e, start/top, single, and range.  Also supplementing
with address comparator types configuration registers access, mandatory
to complete the configuration of the comparator functions.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding sysfs entries to control the ViewInst register's event
selector along with secure and non-secure exception level
instruction tracing.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding sysfs entries to configure:
. global timestamp.
. how often trace synchronisation occur.
. the threashold value for cycle counting.
. branch and broadcasting regions.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adding sysfs entries to:
. set the tracing entity with default values.
. set various mode associated to the tracing entity.
. select the processing entity the tracing entity relates to.
. select various events of interest.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Tracers can be configured with various options at synthesis
time and knowing what resources are available is important for
SW configuration purposes.

As such adding RO sysfs entries for characteristics related to the
tracer implementation.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This driver manages the CoreSight ETMv4 (Embedded Trace Macrocell) IP block
to support HW assisted tracing on ARMv7 and ARMv8 architectures.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NKaixu Xia <xiakaixu@huawei.com>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>