The stm is automatically enabled when an application sets the policy
via ->link() call back by using coresight_enable(), which keeps the
refcount of the current users of the STM. However, the unlink() callback
issues stm_disable() directly, which leaves the STM turned off, without
the coresight layer knowing about it. This prevents any further uses
of the STM hardware as the coresight layer still thinks the STM is
turned on and doesn't enable the hardware when required. Even manually
enabling the STM via sysfs can't really enable the hw.
e.g,
$ echo 1 > $CS_DEVS/$ETR/enable_sink
$ mkdir -p $CONFIG_FS/stp-policy/$source.0/stm_test/
$ echo 32768 65535 > $CONFIG_FS/stp-policy/$source.0/stm_test/channels
$ echo 64 > $CS_DEVS/$source/traceid
$ ./stm_app
Sending 64000 byte blocks of pattern 0 at 0us intervals
Success to map channel(32768~32783) to 0xffffa95fa000
Sending on channel 32768
$ dd if=/dev/$ETR of=~/trace.bin.1
597+1 records in
597+1 records out
305920 bytes (306 kB) copied, 0.399952 s, 765 kB/s
$ ./stm_app
Sending 64000 byte blocks of pattern 0 at 0us intervals
Success to map channel(32768~32783) to 0xffff7e9e2000
Sending on channel 32768
$ dd if=/dev/$ETR of=~/trace.bin.2
0+0 records in
0+0 records out
0 bytes (0 B) copied, 0.0232083 s, 0.0 kB/s
Note that we don't get any data from the ETR for the second session.
Also dmesg shows :
[ 77.520458] coresight-tmc 20800000.etr: TMC-ETR enabled
[ 77.537097] coresight-replicator etr_replicator@20890000: REPLICATOR enabled
[ 77.558828] coresight-replicator main_replicator@208a0000: REPLICATOR enabled
[ 77.581068] coresight-funnel 208c0000.main_funnel: FUNNEL inport 0 enabled
[ 77.602217] coresight-tmc 20840000.etf: TMC-ETF enabled
[ 77.618422] coresight-stm 20860000.stm: STM tracing enabled
[ 139.554252] coresight-stm 20860000.stm: STM tracing disabled
# End of first tracing session
[ 146.351135] coresight-tmc 20800000.etr: TMC read start
[ 146.514486] coresight-tmc 20800000.etr: TMC read end
# Note that the STM is not turned on via stm_generic_link()->coresight_enable()
# and hence none of the components are turned on.
[ 152.479080] coresight-tmc 20800000.etr: TMC read start
[ 152.542632] coresight-tmc 20800000.etr: TMC read end
This patch fixes the problem by balancing the unlink operation by using
the coresight_disable(), keeping the coresight layer in sync with the
hardware state and thus allowing normal usage of the STM component.
Fixes: commit 237483aa5c ("coresight: stm: adding driver for CoreSight STM component")
Cc: Pratik Patel <pratikp@codeaurora.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org # 4.7+
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Reported-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
o STM can hook into the function tracer
o Function filtering now supports more advance glob matching
o Ftrace selftests updates and added tests
o Softirq tag in traces now show only softirqs
o ARM nop added to non traced locations at compile time
o New trace_marker_raw file that allows for binary input
o Optimizations to the ring buffer
o Removal of kmap in trace_marker
o Wakeup and irqsoff tracers now adhere to the set_graph_notrace file
o Other various fixes and clean ups
Note, there are two patches marked for stable. These were discovered
near the end of the 4.9 rc release cycle. By the time I had them tested
it was just a matter of days before 4.9 would be released, and I
figured I would just submit them in the merge window. They are old
bugs and not critical. Nothing non-root could abuse.
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Merge tag 'trace-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"This release has a few updates:
- STM can hook into the function tracer
- Function filtering now supports more advance glob matching
- Ftrace selftests updates and added tests
- Softirq tag in traces now show only softirqs
- ARM nop added to non traced locations at compile time
- New trace_marker_raw file that allows for binary input
- Optimizations to the ring buffer
- Removal of kmap in trace_marker
- Wakeup and irqsoff tracers now adhere to the set_graph_notrace file
- Other various fixes and clean ups"
* tag 'trace-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (42 commits)
selftests: ftrace: Shift down default message verbosity
kprobes/trace: Fix kprobe selftest for newer gcc
tracing/kprobes: Add a helper method to return number of probe hits
tracing/rb: Init the CPU mask on allocation
tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate results
tracing/fgraph: Have wakeup and irqsoff tracers ignore graph functions too
fgraph: Handle a case where a tracer ignores set_graph_notrace
tracing: Replace kmap with copy_from_user() in trace_marker writing
ftrace/x86_32: Set ftrace_stub to weak to prevent gcc from using short jumps to it
tracing: Allow benchmark to be enabled at early_initcall()
tracing: Have system enable return error if one of the events fail
tracing: Do not start benchmark on boot up
tracing: Have the reg function allow to fail
ring-buffer: Force rb_end_commit() and rb_set_commit_to_write() inline
ring-buffer: Froce rb_update_write_stamp() to be inlined
ring-buffer: Force inline of hotpath helper functions
tracing: Make __buffer_unlock_commit() always_inline
tracing: Make tracepoint_printk a static_key
ring-buffer: Always inline rb_event_data()
ring-buffer: Make rb_reserve_next_event() always inlined
...
In STM framework driver, the trace data writing loop would keep running
until it received a negative return value or the whole trace packet has
been written to STM device. So if the .packet() of STM device always
returns zero since the device is not enabled or the parameter isn't
supported, STM framework driver will stall into a dead loop.
Returning -EACCES (Permission denied) in .packet() if the device is
disabled makes more sense, and this is the same for returning -EINVAL
if the channel passed into is not supported.
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If CONFIG_STM_SOURCE_FTRACE is selected, Function trace data can be
writen to sink via STM, all functions that related to writing data
packets to STM should be marked 'notrace' to avoid being traced by
Ftrace, otherwise the program would stall into an endless loop.
Link: http://lkml.kernel.org/r/1479715043-6534-4-git-send-email-zhang.chunyan@linaro.org
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
With this commit [1] address range filter information is now found
in the struct hw_perf_event::addr_filters. As such pass the event
itself to the coresight_source::enable/disable() functions so that
both event attribute and filter can be accessible for configuration.
[1] 'commit 375637bc52 ("perf/core: Introduce address range filtering")'
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The ETM registers are classified into 2 categories: trace and management.
The core power domain contains most of the trace unit logic including
all(except TRCOSLAR and TRCOSLSR) the trace registers. The debug power
domain contains the external debugger interface including all management
registers.
This patch adds coresight unit specific function coresight_simple_func
which can be used for ETM trace registers by providing a ETM specific
read function which does smp cross call to ensure the trace core is
powered up before the register is accessed.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Each coresight device prepares a description for coresight_register()
in struct coresight_desc. Once we register the device, the description is
useless and can be freed. The coresight_desc is small enough (48bytes on
64bit)i to be allocated on the stack. Hence use an automatic variable to
avoid a needless dynamic allocation and wasting the memory(which will only
be free'd when the device is destroyed).
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CoreSight STM device allows direct mapping of the channel regions to
userspace for zero-copy writing. To support this ability, the STM
framework has provided a hook 'mmio_addr', this patch just implemented
this hook for CoreSight STM.
This patch also added an item into 'channel_space' to save the physical
base address of channel region which mmap operation needs to know.
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This driver adds support for the STM CoreSight IP block, allowing any
system compoment (HW or SW) to log and aggregate messages via a
single entity.
The CoreSight STM exposes an application defined number of channels
called stimulus port. Configuration is done using entries in sysfs
and channels made available to userspace via configfs.
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Michael Williams <michael.williams@arm.com>
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suzuki K Poulose