>From the comment in the code, it claims the requirement for byte-address
alignment for RRP register: 'for 32-bit, 64-bit and 128-bit wide trace
memory, the four LSBs must be 0s. For 256-bit wide trace memory, the
five LSBs must be 0s'. This isn't consistent with the program, the
program sets five LSBs as zeros for 32/64/128-bit wide trace memory and
set six LSBs zeros for 256-bit wide trace memory.
After checking with the CoreSight Trace Memory Controller technical
reference manual (ARM DDI 0461B, section 3.3.4 RAM Read Pointer
Register), it proves the comment is right and the program does wrong
setting.
This patch fixes byte-address alignment for RRP by following correct
definition in the technical reference manual.
Cc: Mathieu Poirier <mathieu.poirier(a)linaro.org>
Cc: Mike Leach <mike.leach(a)linaro.org>
Signed-off-by: Leo Yan <leo.yan(a)linaro.org>
---
drivers/hwtracing/coresight/coresight-tmc-etf.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 0549249..e310613 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -438,10 +438,10 @@ static void tmc_update_etf_buffer(struct coresight_device *csdev,
case TMC_MEM_INTF_WIDTH_32BITS:
case TMC_MEM_INTF_WIDTH_64BITS:
case TMC_MEM_INTF_WIDTH_128BITS:
- mask = GENMASK(31, 5);
+ mask = GENMASK(31, 4);
break;
case TMC_MEM_INTF_WIDTH_256BITS:
- mask = GENMASK(31, 6);
+ mask = GENMASK(31, 5);
break;
}
--
2.7.4
In ETB dump function tmc_etb_dump_hw() it has nested loops. The second
level loop is to iterate index in the range [0 .. drvdata->memwidth);
but the index isn't really used in the code, thus the second level
loop is useless.
This patch is to remove the second level loop; the refactor also reduces
indentation and we can use 'break' to replace 'goto' tag.
Cc: Mathieu Poirier <mathieu.poirier(a)linaro.org>
Signed-off-by: Leo Yan <leo.yan(a)linaro.org>
---
drivers/hwtracing/coresight/coresight-tmc-etf.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 9c599c9..8b34161 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -34,23 +34,20 @@ static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata)
{
char *bufp;
u32 read_data, lost;
- int i;
/* Check if the buffer wrapped around. */
lost = readl_relaxed(drvdata->base + TMC_STS) & TMC_STS_FULL;
bufp = drvdata->buf;
drvdata->len = 0;
while (1) {
- for (i = 0; i < drvdata->memwidth; i++) {
- read_data = readl_relaxed(drvdata->base + TMC_RRD);
- if (read_data == 0xFFFFFFFF)
- goto done;
- memcpy(bufp, &read_data, 4);
- bufp += 4;
- drvdata->len += 4;
- }
+ read_data = readl_relaxed(drvdata->base + TMC_RRD);
+ if (read_data == 0xFFFFFFFF)
+ break;
+ memcpy(bufp, &read_data, 4);
+ bufp += 4;
+ drvdata->len += 4;
}
-done:
+
if (lost)
coresight_insert_barrier_packet(drvdata->buf);
return;
--
2.7.4
Coresight uses DT graph bindings to describe the connections of the
components. However we have some undocumented usage of the bindings
to describe some of the properties of the connections.
The coresight driver needs to know the hardware ports invovled
in the connection and the direction of data flow to effectively
manage the trace sessions. So far we have relied on the "port"
address (as described by the generic graph bindings) to represent
the hardware port of the component for a connection.
The hardware uses separate numbering scheme for input and output
ports, which implies, we could have two different (input and output)
ports with the same port number. This could create problems in the
graph bindings where the label of the port wouldn't match the address.
e.g, with the existing bindings we get :
port@0{ // Output port 0
reg = <0>;
...
};
port@1{
reg = <0>; // Input port 0
endpoint {
slave-mode;
...
};
};
With the new enforcement in the DT rules, mismatches in label and address
are not allowed (as see in the case for port@1). So, we need a new mechanism
to describe the hardware port number reliably.
Also, we relied on an undocumented "slave-mode" property (see the above
example) to indicate if the port is an input port. Let us formalise and
switch to a new property to describe the direction of data flow.
There were three options considered for the hardware port number scheme:
1) Use natural ordering in the DT to infer the hardware port number.
i.e, Mandate that the all ports are listed in the DT and in the ascending
order for each class (input and output respectively).
Pros :
- We don't need new properties and if the existing DTS list them in
order (which most of them do), they work out of the box.
Cons :
- We must list all the ports even if the system cannot/shouldn't use
it.
- It is prone to human errors (if the order is not kept).
2) Use an explicit property to list both the direction and the hw port
number and direction. Define "coresight,hwid" as 2 member array of u32,
where the members are port number and the direction respectively.
e.g
port@0{
reg = <0>;
endpoint {
coresight,hwid = <0 1>; // Port # 0, Output
}
};
port@1{
reg = <1>;
endpoint {
coresight,hwid = <0 0>; // Port # 0, Input
};
};
Pros:
- The bindings are formal but not so reader friendly and could
potentially lead to human errors.
Cons:
- Backward compatiblity is lost.
3) Use explicit properties (implemented in the series) for the hardware
port id and direction. We define a new property "coresight,hwid" for
each endpoint in coresight devices to specify the hardware port number
explicitly. Also use a separate property "direction" to specify the
direction of the data flow.
e.g,
port@0{
reg = <0>;
endpoint {
direction = <1>; // Output
coresight,hwid = <0>; // Port # 0
}
};
port@1{
reg = <1>;
endpoint {
direction = <0>; // Input
coresight,hwid = <0>; // Port # 0
};
};
Pros:
- The bindings are formal and reader friendly, and less prone to errors.
Cons:
- Backward compatibility is lost.
After a round of discussions [1], the following option (4) is adopted :
4) Group ports based on the directions under a dedicated node. This has been
checked with the upstream DTC tool to resolve the "address mismatch" issue.
e.g,
out-ports { // Output ports for this component
port@0 { // Outport 0
reg = 0;
endpoint { ... };
};
port@1 { // Outport 1
reg = 1;
endpoint { ... };
};
};
in-ports { // Input ports for this component
port@0 { // Inport 0
reg = 0;
endpoint { ... };
};
port@1 { // Inport 1
reg = 1;
endpoint { ... };
};
};
This series implements Option (4) listed above and falls back to the old
bindings if the new bindings are not available. This allows the systems
with old bindings work with the new driver. The driver now issues a warning
(once) when it encounters the old bindings. The series contains DT update
for Juno platform. The remaining in-kernel sources could be updated once
we are fine with the proposal.
It also cleans up the platform parsing code to reduce the memory usage by
reusing the platform description.
Applies on coresight/next
Changes since V2:
- Clean of_coresight_parse_endpoint() to return 1 to indicate a connection
record was updated.
- Drop documentation for old bindings
Changes since V1:
- Implement the proposal by Rob.
- Drop the DTS updates for all platforms except Juno
- Drop the incorrect fix in coresight_register. Instead document the code
to prevent people trying to un-fix it again.
- Add a patch to drop remote device references in DT graph parsing
- Split of_node refcount fixing patch, fix a typo in the comment.
- Add Reviewed-by tags from Mathieu.
- Drop patches picked up for 4.18-rc series
Changes since RFC:
- Fixed style issues
- Fix an existing memory leak coresight_register (Found in code update)
- Fix missing of_node_put() in the existing driver (Reported-by Mathieu)
- Update the existing dts in kernel tree.
Suzuki K Poulose (9):
coresight: Document error handling in coresight_register
coresight: platform: Refactor graph endpoint parsing
coresight: platform: Fix refcounting for graph nodes
coresight: platform: Fix leaking device reference
coresight: Fix remote endpoint parsing
coresight: Add helper to check if the endpoint is input
coresight: platform: Cleanup coresight connection handling
coresight: Cleanup coresight DT bindings
dts: juno: Update coresight bindings
.../devicetree/bindings/arm/coresight.txt | 95 +++++---
arch/arm64/boot/dts/arm/juno-base.dtsi | 161 ++++++------
arch/arm64/boot/dts/arm/juno-cs-r1r2.dtsi | 52 ++--
arch/arm64/boot/dts/arm/juno.dts | 13 +-
drivers/hwtracing/coresight/coresight.c | 35 +--
drivers/hwtracing/coresight/of_coresight.c | 269 ++++++++++++++-------
include/linux/coresight.h | 9 +-
7 files changed, 359 insertions(+), 275 deletions(-)
--
2.7.4
On Wed, 8 Aug 2018 at 01:59, Tomasz Nowicki <tnowicki(a)caviumnetworks.com> wrote:
>
> Hi Mathieu,
>
> It's been a while but I am back to Coresight.
>
> Let me remind my setup and the issue I am struggling with now.
>
> Kernel baseline:
> https://github.com/Linaro/perf-opencsd (perf-opencsd-v4.16)
> OpenCSD:
> https://github.com/Linaro/OpenCSD.git (master)
>
> The simplest Coresight components path I used as a start point:
> ETMv4.1 -> TDR -> FUNNEL -> ETF
>
> As I mentioned TDR is built by Cavium and it was added to aggregate 128
> inputs into one output rather than cascading funnels. TDR has its own
> driver just to keep path connected in Linux Coresight framework.
>
> Here is how I catch some trace data:
> sudo perf record -C 0 -e cs_etm/@etf0/ --per-thread test_app
The above command line tells perf to trace everything that is
happening on CPU0 for as long as "test_app" is executing. In this
case the "--per-thread" option is ignored. This is called a CPU-wide
trace scenario and is currently not supported for CS (I am currently
working on it).
If you want to make sure "test_app" executes on CPU0 and that you
trace just that you will need to use the "taskset" utility:
sudo perf record -e cs_etm/@etf0/ --per-thread taskset 0x1 test_app
An alternative to the above would be to CPU-hotplug out CPU128-255
while you are testing.
Let's start with that before going further.
Thanks,
Mathieu
>
> I need to use -C because my machines has 2 nodes, 32 cores (128 threads)
> each and each node has different ETF. So I have to specify which CPU is
> the source and for specified ETF sink (EFT0 can be a sink for
> CPU0-CPU127, ETF1 can be a sink for CPU128-CPU255). Otherwise Linux
> cannot find path for ETMs related to CPU128-CPU255 if I specify ETF0 as
> a sink.
>
> Overall, I can see some data using:
> # sudo perf report --stdio --dump
> [...]
> . ... CoreSight ETM Trace data: size 16384 bytes
> Frame deformatter: Found 4 FSYNCS
> ID:12 RESET operation on trace decode path
> Idx:108; ID:12; I_NOT_SYNC : I Stream not synchronised
> Idx:455; ID:12; I_ASYNC : Alignment Synchronisation.
> Idx:468; ID:12; I_TRACE_INFO : Trace Info.; INFO=0x0
> Idx:470; ID:12; I_TRACE_ON : Trace On.
> Idx:471; ID:12; I_CTXT : Context Packet.; Ctxt: AArch64,EL0, NS;
> Idx:473; ID:12; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.;
> Addr=0x0000AAABE0B09584;
> Idx:483; ID:12; I_ATOM_F1 : Atom format 1.; N
> Idx:484; ID:12; I_TIMESTAMP : Timestamp.; Updated val =
> 0x1b6a5d937cc1
> Idx:492; ID:12; I_ATOM_F3 : Atom format 3.; NNE
> Idx:493; ID:12; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.;
> Addr=0x0000AAABE0B0D210;
> Idx:504; ID:12; I_ATOM_F3 : Atom format 3.; NEE
> Idx:505; ID:12; I_ATOM_F3 : Atom format 3.; NEN
> Idx:506; ID:12; I_ATOM_F6 : Atom format 6.; EEEN
> Idx:507; ID:12; I_ATOM_F3 : Atom format 3.; NNE
> Idx:508; ID:12; I_ATOM_F1 : Atom format 1.; N
> Idx:509; ID:12; I_ATOM_F3 : Atom format 3.; NNN
> Idx:510; ID:12; I_ATOM_F3 : Atom format 3.; EEN
> Idx:512; ID:12; I_ATOM_F1 : Atom format 1.; E
> [...]
>
> However, I still see errors while using:
> # sudo perf report --stdio
> 0x1e8 [0x60]: failed to process type: 1
> Error:
> failed to process sample
> # To display the perf.data header info, please use
> --header/--header-only options.
>
> The reason is that cs_etm__process_event() is failing on:
> if (!etm->timeless_decoding)
> return -EINVAL;
>
> and etm->timeless_decoding is setup in cs_etm__is_timeless_decoding().
> For some events time bit set and so far I failed to figure out what is
> going on. Have you met similar issue so far? Any pointers or hints are
> very appreciated.
>
> One more comment below.
>
> On 10.01.2018 21:10, Mathieu Poirier wrote:
> > On 10 January 2018 at 06:57, Tomasz Nowicki <tnowicki(a)caviumnetworks.com> wrote:
> >> Hello Mathieu,
> >>
> >> Thank you for your response. Please see comments below.
> >>
> >> On 08.01.2018 17:53, Mathieu Poirier wrote:
> >>>
> >>> Good day Tomasz,
> >>>
> >>>
> >>> On 5 January 2018 at 05:51, tn <Tomasz.Nowicki(a)caviumnetworks.com> wrote:
> >>>>
> >>>> Hi Mathieu,
> >>>>
> >>>> I am bringing up Coresight functiproject zeroonality on ThunderX2. While
> >>>> ramping up I
> >>>> come across your Connect session:
> >>>>
> >>>> which I found very helpful.
> >>>
> >>>
> >>> Perfect - a few things have changed since then, see below.
> >>>
> >>>>
> >>>> During my research I had to create new Coresight component driver for
> >>>> Linux,
> >>>> here is the story. For ThunderX2, we aggregate data trace from all 128
> >>>> ETMs
> >>>> into one funnel inport using so called TDR (Trace Data Ring) component.
> >>>> This
> >>>> should be transparent to software and does not require configuration at
> >>>> all.
> >>>> However, Linux Coresight framework requires components to be connected
> >>>> each
> >>>> other so we cannot leave funnel and ETMs disconnected in DT. I decided to
> >>>> create pure software component i.e. TDR which is meant to connect chain
> >>>> only, no actions on registers.
> >>>
> >>>
> >>> Is this TDR an ARM IP or built in-house by Cavium?
> >>
> >>
> >> This is Cavium specific component which I am going to upstream once I test
> >> the whole functionality.
> >>
> >> And I suppose it
> >>>
> >>> was added there to aggregate 128 input into one output rather than
> >>> cascading funnels?
> >>
> >>
> >> Correct.
> >>
> >>>>
> >>>> Now I am able to enable ETF sink and path from ETM via TDR via FUNNEL up
> >>>> to
> >>>> ETF and gather some data. To be sure things work properly I want to
> >>>> decode
> >>>> data using Linaro OpenCSD library following instructions from here:
> >>>>
> >>>> https://community.arm.com/tools/b/blog/posts/do-a-coresight-trace-on-linux-…
> >>>
> >>>
> >>> Thanks for pointing this out, I didn't know about it.
> >>>
> >>>> but still got error while doing 'perf report' step. Kernel perf tool
> >>>> support
> >>>> for OpenCSD is out of tree for now so I may miss some patches.
> >>>
> >>>
> >>> Can you get me a pastebin of the errors you're getting?
> >>
> >>
> >> Sure, see:
> >> https://pastebin.com/6YDq8KfC
> >> As you see there is not much info about error cause.
> >>
> >>>
> >>>>
> >>>> Here is my setup:
> >>>> https://github.com/Linaro/perf-opencsd/commits/upstream-v1 (+ ThunderX2
> >>>> specific patches)
> >>>
> >>>
> >>> Oh boy... I wasn't expecting people to use that but I suppose it is
> >>> the right thing to do. Keep going with that code.
> >>>
> >>>> https://github.com/Linaro/OpenCSD/commits/master
> >>>
> >>>
> >>> This, in combination with the upstream-v1 branch should work properly.
> >>> That's how I test things on my Juno and Dragon board.
> >>>
> >>>>
> >>>> # echo 1 > etf0/enable_sink
> >>>> # perf record -C 0 -e cs_etm// sleep 2
> >>>
> >>>
> >>> Ok, that won't work as the -C option is currently not supported (I am
> >>> working on it). I also suggest to make sure you have the very latest
> >>> TIP [1] on branch [2] and to carefully read the README.md. We
> >>> recently updated the instructions to fit the newest development.
> >>> Lastly we have deprecated enabling the sink from the sysFS interface -
> >>> it can still work but no guarantees are provided. It is better to
> >>> specify the sink as part of the perf record command line, as shown in
> >>> the most recent HOWTO.md.
> >>
> >>
> >> I am able to specify sink as part of the perf record command line only for
> >> Linux Perf master branch:
> >> https://github.com/Linaro/perf-opencsd/commits/master
> >>
> >> For upstream-v1 branch I am getting:
> >> $ perf record -vvv -e cs_etm/@etf0/ --per-thread uname
> >> Using CPUID 0x00000000420f5160
> >> perf: util/evsel.c:783: apply_config_terms: Assertion `!(1)' failed.
> >> Aborted (core dumped)
> >
> >
> > Ok, I've uploaded upstream-v2. With that branch everything works fine
> > on my side, no changes needed. I added a fix for a regression in the
> > perf tip tree and the code required to use the ETR from the perf
> > interface.
> >
> > One thing about the above: "@etf0". Is this really the name you gave
> > to the device in the DT? Look under /sys/bus/coresight/devices/ for
> > an etf entry. What is listed there should is the name of the ETF as
> > it is known to the system.
>
> Indeed, the name is different but for perf command clarity I use shortcut.
>
> Thanks,
> Tomasz
+CoreSight ML and Mathieu
---------- Forwarded message ----------
From: Mike Leach <mike.leach(a)linaro.org>
Date: 3 September 2018 at 17:39
Subject: Re: Failed for ETM decoding with db410c snapshot mode
To: Leo Yan <leo.yan(a)linaro.org>
HI Leo,
Short summary - there is a problem with the trace collected - not the
decoder. See below for details
On 3 September 2018 at 08:06, <leo.yan(a)linaro.org> wrote:
> Hi Mike, Mathieu,
>
> [ + CoreSight ML ]
>
> When I work on the CoreSight + perf tool and used crash extension
> program to extract the tracing data from perf aux buffer, finally I
> can get the trace data for about 1.6MB from ETF sink from DB410c board.
>
> To verify the extracted trace data, I used 'snapshot' mode under
> OpenCSD code base, you could see the tar file for this [1]. After
> you download this file, you could place it under OpenCSD folder:
>
> $ cp db410c_snapshot_kdump.tgz my_opencsd/decoder/tests/snapshots
> $ cd my_opencsd/decoder/tests/snapshots
> $ tar zxvf db410c_snapshot_kdump.tgz
> $ cd db410c_snapshot_kdump
>
> $ ../../bin/builddir/trc_pkt_lister
This will print raw trace packets as it finds them without attempting
any sort of interpretation.
> $ ../../bin/builddir/trc_pkt_lister -decode
This will try to decode the raw trace packets into a sequence of
instructions executed (alongside the raw packets)
This is where the packets are being flagged as incorrect.
>
> If I use the command 'trc_pkt_lister' without any extra options, it
> can print out trace packets successfully; but if I add the extra
> option '-decode' it uses 'decode all' mode and it reports the errors as:
>
> 483710 Idx:53086; ID:10; [0xf8 ]; I_ATOM_F3 : Atom format 3.; NNN
> 483711 Idx:53086; ID:10; OCSD_GEN_TRC_ELEM_ADDR_NACC( 0xffff000008abc9f0 )
> 483712 Idx:53088; ID:10; [0xdb ]; I_ATOM_F2 : Atom format 2.; EE
> 483713 Idx:53194; ID:10; [0x6b 0x8c 0x08 0xfa 0xdc 0x95 0x5c ]; I_COND_RES_F1 : Conditional Result, format 1.
This is a conditional result trace packet - however as far as I am
aware the trace unit on an A53 (i.e. DB410 core) cannot produce these.
Additionally in the entire file I see 2 I_COND packets and 1
I_NUM_DS_MKR - a data synchronisation marker packet.
Now Data sync can only ever occur if data trace is supported and
enabled. Data trace is architecturally prohibited for A class v8 cores
(and unimplemented on most A class v7 cores).
If there were tracing of conditional elements occurring, and it were
enabled, then the packets should match up - a cond instruction should
match with one cond result element.
But in the end - event without these inconsistencies - the TRACE_INFO
element at the top of the listing tells me that conditional
instruction trace is disabled.
Thus you are seeing what I believe is the effect of concatenating
trace data buffers together (you mention you have 1.6MB of data from
the ETF - which is not that large), without inserting barrier packets
in between.
The decoder cannot spot the boundaries, and will carry on and be out
of sync so can mis-read trace packet payload data as header data which
will throw off the decode process.
When I look at the raw byte data I am seeing this at the top of the listing:-
Frame Data; Index 0; ID_DATA[????]; ff
Frame Data; Index 0; ID_DATA[0x7f]; 7f ff 7f ff 7f ff
This does not look valid at all to me.
> 483714 DCD_ETMV4_0016 : 0x0018 (OCSD_ERR_BAD_DECODE_PKT) [Reserved or unknown packet in decoder.]; Unsupported packet type.Trace Packet Lister : Data Path fatal error
> 483715 0x0018 (OCSD_ERR_BAD_DECODE_PKT) [Reserved or unknown packet in decoder.]; Unsupported packet type.Trace Packet Lister : Trace buffer done, processed 53216 bytes.
>
> You also could check detailed log trc_pkt_lister.ppl in the shared
> tar packet; After searched for the OpenCSD code and found this error is
> due it cannot support some types of packets [2].
>
> So want to check what's the best for this issue; seems to me we need
> to fix this so it can support well to complete the decoding?
>
The reason we have not implemented support for these packets, is that
we have never seen an implementation that generates them.
regards
Mike
> Thanks in advance for suggestion.
> Leo Yan
>
> [1] http://people.linaro.org/~leo.yan/opencsd_db410c/db410c_snapshot_kdump.tgz
> [2] https://github.com/Linaro/OpenCSD/blob/master/decoder/source/etmv4/trc_pkt_…
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
Greetings,
I'm trying to enable the Coresight ETMv4 trace from kernel mode. I saw
there is no documentation on how to do this, except using the sysfs user
mode interface and perf.
To overcome this i looked a little bit in the coresight.h header file, and
came to these APIs:
> extern int coresight_enable(struct coresight_device *csdev);
>
> extern void coresight_disable(struct coresight_device *csdev);
And the sysfs implementation uses these APIs when enabing/disabling the
trace code, so i thought this could suit my needs. The next problem was
actually getting the coresight devices data structures, which aren't
exported and are actually provided internally to perf and sysfs. So i
exported the coresight bus type:
struct bus_type coresight_bustype = {
>
> .name = "coresight",
>
> };
>
> EXPORT_SYMBOL(coresight_bustype);
And enumerated the bus and just looked for the
type CORESIGHT_DEV_TYPE_SOURCE, since the only source on my board is ETMv4,
there isn't any conflicts so i should get only ETMv4s.
This worked, and indeed i collected a coresight device for every CPU, and
enabled the trace successfully while being in *non-atomic context*.
The problem is, i must enable the trace in *atomic context synchronously *on
the current thread's CPU(i can't issue a work-queue to enable the trace for
me). So.. i got many BUG() errors because of non-atomic API usage, for
example, the allocation of the TMC-ETR buffer:
> dma_alloc_coherent(drvdata->dev, etr_buf->size,
> &flat_buf->daddr, *GFP_KERNEL*);
So my questions are:
1) Is there a more documented way of enabling coresight from kernel mode? i
believe i achieved this using cheats.
2) I see there is no exported kernel API to config the coresight trace
attributes(for example, filter EL0). I can only do so from sysfs.. am i
missing something?
3) Are there any plans to make the Coresight infrastructure atomic-context
friendly?
If there are, is the development in progress? if not.. how would you
suggest tackling the issues i've described in this message?
Thank you!
Hi,
I have followed procedure to integrate libopenCSD in perf tool in target ARM. (based on kernel 4.18rc1)
I’ve seen in documentation that perf record need parameters cs_etm/(a)xxxxx.etr/u …<mailto:cs_etm/@xxxxx.etr/u%20…>
I would like to know if ETR device is mandatory to use coresight trace with perf ?
In my architecture, I’ve :
1 .funnel
1 .tpiu
2 .etm
1 .etf
1 .stm
1 replicator but no ETR ☹
If possible without ETR, do you have examples of perf record cmd usage ?
I’ve configured my coresight register as followed :
echo 1 > /sys/bus/coresight/devices/xxxx.stm/hwevent_select
echo 2 > /sys/bus/coresight/devices/xxxx.stm/hwevent_extmux_select
// Need to track IRQ up of UART
echo 0x200000 > /sys/bus/coresight/devices/xxxx.stm/hwevent_enable
echo 1 > /sys/bus/coresight/devices/yyyy.etf/enable_sink
echo 1 > /sys/bus/coresight/devices/xxxx.stm/enable_source
Which perf record cmd I must enter to catch my STM event ?
Thanks for your help.
Christophe.
Hi Mike, Mathieu,
[ + CoreSight ML ]
When I work on the CoreSight + perf tool and used crash extension
program to extract the tracing data from perf aux buffer, finally I
can get the trace data for about 1.6MB from ETF sink from DB410c board.
To verify the extracted trace data, I used 'snapshot' mode under
OpenCSD code base, you could see the tar file for this [1]. After
you download this file, you could place it under OpenCSD folder:
$ cp db410c_snapshot_kdump.tgz my_opencsd/decoder/tests/snapshots
$ cd my_opencsd/decoder/tests/snapshots
$ tar zxvf db410c_snapshot_kdump.tgz
$ cd db410c_snapshot_kdump
$ ../../bin/builddir/trc_pkt_lister
$ ../../bin/builddir/trc_pkt_lister -decode
If I use the command 'trc_pkt_lister' without any extra options, it
can print out trace packets successfully; but if I add the extra
option '-decode' it uses 'decode all' mode and it reports the errors as:
483710 Idx:53086; ID:10; [0xf8 ]; I_ATOM_F3 : Atom format 3.; NNN
483711 Idx:53086; ID:10; OCSD_GEN_TRC_ELEM_ADDR_NACC( 0xffff000008abc9f0 )
483712 Idx:53088; ID:10; [0xdb ]; I_ATOM_F2 : Atom format 2.; EE
483713 Idx:53194; ID:10; [0x6b 0x8c 0x08 0xfa 0xdc 0x95 0x5c ]; I_COND_RES_F1 : Conditional Result, format 1.
483714 DCD_ETMV4_0016 : 0x0018 (OCSD_ERR_BAD_DECODE_PKT) [Reserved or unknown packet in decoder.]; Unsupported packet type.Trace Packet Lister : Data Path fatal error
483715 0x0018 (OCSD_ERR_BAD_DECODE_PKT) [Reserved or unknown packet in decoder.]; Unsupported packet type.Trace Packet Lister : Trace buffer done, processed 53216 bytes.
You also could check detailed log trc_pkt_lister.ppl in the shared
tar packet; After searched for the OpenCSD code and found this error is
due it cannot support some types of packets [2].
So want to check what's the best for this issue; seems to me we need
to fix this so it can support well to complete the decoding?
Thanks in advance for suggestion.
Leo Yan
[1] http://people.linaro.org/~leo.yan/opencsd_db410c/db410c_snapshot_kdump.tgz
[2] https://github.com/Linaro/OpenCSD/blob/master/decoder/source/etmv4/trc_pkt_…