Changelog from v1:
* V2 is a complete patchset with kernel panic trace tested on Linux 6.4.
Details on testing with relevant console logs has been added for reference.
* Two additional patches(patch 6 & 7) has been included to manage stopping of trace
at the time of kernel panic.
* Few bug fixes.
TODO:
* Add support to prevent overwriting of trace data captured in previous
boot. (Suggested by James)
* DTS properties for reserved memory might need some refinements,
since Linux arm64 kernel has limitation on the number of reserved
regions it supports(ie. 64).
* ETM & CTI configuration using system configuration manager is a work
progress. Currently ETM configuration is done in the driver(patch 7) and CTI
configuration is done using CTI sysfs interface.
* Reading tracedata from crashdump kernel is not tested.
* Perf based trace capture is not tested.
Introduction
============
This RFC is about extending Linux coresight driver support to address
kernel panic and watchdog reset scenarios. This would help coresight
users to debug kernel panic and watchdog reset with the help of coresight
trace data.
For simplicity, watchdog and kernel panic are addressed in separate
sections.
Coresight trace capture: Kernel panic
-------------------------------------
From the coresight driver point of view, addressing the kernel panic
situation has four main requirements.
a. Support for allocation of trace buffer pages from reserved memory area.
Platform can advertise this using a new device tree property added to
relevant coresight nodes.
b. Support for stopping coresight blocks at the time of panic
c. Saving required metadata in the specified format
d. Support for reading trace data captured at the time of panic
Allocation of trace buffer pages from reserved RAM
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A new optional device tree property "memory-region" is added to the
ETR/ETF device nodes, that would give the base address and size of trace
buffer.
Static allocation of trace buffers would ensure that both IOMMU enabled
and disabled cases are handled. Also, platforms that support persistent
RAM will allow users to read trace data in the subsequent boot without
booting the crashdump kernel.
Note:
For ETR sink devices, this reserved region will be used for both trace
capture and trace data retrieval.
For ETF sink devices, internal SRAM would be used for trace capture,
and they would be synced to reserved region for retrieval.
Note: Patches 1 & 2 adds support for this.
Disabling coresight blocks at the time of panic
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In order to avoid the situation of losing relevant trace data after a
kernel panic, it would be desirable to stop the coresight blocks at the
time of panic.
This can be achieved by configuring the comparator, CTI and sink
devices as below,
Comparator(triggers on kernel panic) --->External out --->CTI --
|
ETR/ETF stop <------External In <--------------
Note:
* Patch 6 provides the necessary ETR configuration.
* Patch 7 provides the necessary ETM configuration.
Saving metadata at the time of kernel panic
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Coresight metadata involves all additional data that are required for a
successful trace decode in addition to the trace data. This involves
ETR/ETF, ETE register snapshot etc.
A new optional device property "memory-region" is added to
the ETR/ETF/ETE device nodes for this.
Note: Patches 3 & 4 adds support for this.
Reading trace data captured at the time of panic
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Trace data captured at the time of panic, can be read from rebooted kernel
or from crashdump kernel using the below mentioned interface.
Note: Patch 5 adds support for this.
Steps for reading trace data captured in previous boot
++++++++++++++++++++++++++++++++++++++++++++++++++++++
1. cd /sys/bus/coresight/devices/tmc_etrXX/
2. Change to special mode called, read_prevboot.
#echo 1 > read_prevboot
3. Dump trace buffer data to a file,
#dd if=/dev/tmc_etrXX of=~/cstrace.bin
4. Reset back to normal mode
#echo 0 > read_prevboot
General flow of trace capture and decode incase of kernel panic
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1. Enable source and sink on all the cores using the sysfs interface.
ETR sink will have trace buffers allocated from reserved memory.
2. Run relevant tests.
3. On a kernel panic, all coresight blocks are disabled, necessary
metadata is synced by kernel panic handler.
System would eventually reboot or boot a crashdump kernel.
4. For platforms that supports crashdump kernel, raw trace data can be
dumped using the coresight sysfs interface from the crashdump kernel
itself. Persistent RAM is not a requirement in this case.
5. For platforms that supports persistent RAM, trace data can be dumped
using the the coresight sysfs interface in the subsequent Linux boot.
Crashdump kernel is not a requirement in this case. Persistent RAM
ensures that trace data is intact across reboot.
Coresight trace capture: Watchdog reset
---------------------------------------
The main difference between addressing the watchdog reset and kernel panic
case are below,
a. Saving coresight metadata need to be taken care by the
SCP(system control processor) firmware in the specified format,
instead of kernel.
b. Reserved memory region given by firmware for trace buffer and metadata
has to be in persistent RAM.
Note: This is a requirement for watchdog reset case but optional
in kernel panic case.
Watchdog reset can be supported only on platforms that meet the above
two requirements.
Testing Kernel panic on Linux 6.4
---------------------------------
1. Configure CTI using sysfs interface
#./cti_setup.sh
#cat cti_setup.sh
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
cd /sys/bus/coresight/devices/
ap_cti_config () {
#ETM trig out[0] trigger to Channel 0
echo 0 4 > channels/trigin_attach
}
etf_cti_config () {
#ETF Flush in trigger from Channel 0
echo 0 1 > channels/trigout_attach
echo 1 > channels/trig_filter_enable
}
etr_cti_config () {
#ETR Flush in from Channel 0
echo 0 1 > channels/trigout_attach
echo 1 > channels/trig_filter_enable
}
ctidevs=`find . -name "cti*"`
for i in $ctidevs
do
cd $i
connection=`find . -name "ete*"`
if [ ! -z "$connection" ]
then
echo "AP CTI config for $i"
ap_cti_config
fi
connection=`find . -name "tmc_etf*"`
if [ ! -z "$connection" ]
then
echo "ETF CTI config for $i"
etf_cti_config
fi
connection=`find . -name "tmc_etr*"`
if [ ! -z "$connection" ]
then
echo "ETR CTI config for $i"
etr_cti_config
fi
cd ..
done
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Note: CTI connections are SOC specific and hence the above script is
just for reference.
2. Start Coresight tracing on cores 1 and 2 using sysfs interface
3. Run some application on core 1
#taskset -c 1 dd if=/dev/urandom of=/dev/null &
4. Invoke kernel panic on core 2
#echo 1 > /proc/sys/kernel/panic
#taskset -c 2 echo c > /proc/sysrq-trigger
5. From rebooted kernel, enable previous boot mode
#echo 1 > /sys/bus/coresight/devices/tmc_etr0/read_prevboot
6. Read trace data
#dd if=/dev/tmc_etr0 of=/trace/cstrace.bin
7. Run opencsd decoder tools/scripts to generate the instruction trace.
Core 1 instruction trace dump:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
A etm4_enable_hw: ffff800008ae1dd4
CONTEXT EL2 etm4_enable_hw: ffff800008ae1dd4
I etm4_enable_hw: ffff800008ae1dd4:
d503201f nop
I etm4_enable_hw: ffff800008ae1dd8:
d503201f nop
I etm4_enable_hw: ffff800008ae1ddc:
d503201f nop
I etm4_enable_hw: ffff800008ae1de0:
d503201f nop
I etm4_enable_hw: ffff800008ae1de4:
d503201f nop
I etm4_enable_hw: ffff800008ae1de8:
d503233f paciasp
I etm4_enable_hw: ffff800008ae1dec:
a9be7bfd stp x29, x30, [sp, #-32]!
I etm4_enable_hw: ffff800008ae1df0:
910003fd mov x29, sp
I etm4_enable_hw: ffff800008ae1df4:
a90153f3 stp x19, x20, [sp, #16]
I etm4_enable_hw: ffff800008ae1df8:
2a0003f4 mov w20, w0
I etm4_enable_hw: ffff800008ae1dfc:
900085b3 adrp x19, ffff800009b95000 <reserved_mem+0xc48>
I etm4_enable_hw: ffff800008ae1e00:
910f4273 add x19, x19, #0x3d0
I etm4_enable_hw: ffff800008ae1e04:
f8747a60 ldr x0, [x19, x20, lsl #3]
E etm4_enable_hw: ffff800008ae1e08:
b4000140 cbz x0, ffff800008ae1e30 <etm4_starting_cpu+0x50>
I 149.039572921 etm4_enable_hw: ffff800008ae1e30:
a94153f3 ldp x19, x20, [sp, #16]
I 149.039572921 etm4_enable_hw: ffff800008ae1e34:
52800000 mov w0, #0x0 // #0
I 149.039572921 etm4_enable_hw: ffff800008ae1e38:
a8c27bfd ldp x29, x30, [sp], #32
..snip
149.052324811 chacha_block_generic: ffff800008642d80:
9100a3e0 add x0,
I 149.052324811 chacha_block_generic: ffff800008642d84:
b86178a2 ldr w2, [x5, x1, lsl #2]
I 149.052324811 chacha_block_generic: ffff800008642d88:
8b010803 add x3, x0, x1, lsl #2
I 149.052324811 chacha_block_generic: ffff800008642d8c:
b85fc063 ldur w3, [x3, #-4]
I 149.052324811 chacha_block_generic: ffff800008642d90:
0b030042 add w2, w2, w3
I 149.052324811 chacha_block_generic: ffff800008642d94:
b8217882 str w2, [x4, x1, lsl #2]
I 149.052324811 chacha_block_generic: ffff800008642d98:
91000421 add x1, x1, #0x1
I 149.052324811 chacha_block_generic: ffff800008642d9c:
f100443f cmp x1, #0x11
Core 2 instruction trace dump(kernel panic triggered core):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A etm4_enable_hw: ffff800008ae1dd4
CONTEXT EL2 etm4_enable_hw: ffff800008ae1dd4
I etm4_enable_hw: ffff800008ae1dd4:
d503201f nop
I etm4_enable_hw: ffff800008ae1dd8:
d503201f nop
I etm4_enable_hw: ffff800008ae1ddc:
d503201f nop
I etm4_enable_hw: ffff800008ae1de0:
d503201f nop
I etm4_enable_hw: ffff800008ae1de4:
d503201f nop
I etm4_enable_hw: ffff800008ae1de8:
d503233f paciasp
I etm4_enable_hw: ffff800008ae1dec:
a9be7bfd stp x29, x30, [sp, #-32]!
I etm4_enable_hw: ffff800008ae1df0:
910003fd mov x29, sp
I etm4_enable_hw: ffff800008ae1df4:
a90153f3 stp x19, x20, [sp, #16]
I etm4_enable_hw: ffff800008ae1df8:
2a0003f4 mov w20, w0
I etm4_enable_hw: ffff800008ae1dfc:
900085b3 adrp x19, ffff800009b95000 <reserved_mem+0xc48>
I etm4_enable_hw: ffff800008ae1e00:
910f4273 add x19, x19, #0x3d0
I etm4_enable_hw: ffff800008ae1e04:
f8747a60 ldr x0, [x19, x20, lsl #3]
E etm4_enable_hw: ffff800008ae1e08:
b4000140 cbz x0, ffff800008ae1e30 <etm4_starting_cpu+0x50>
I 149.046243445 etm4_enable_hw: ffff800008ae1e30:
a94153f3 ldp x19, x20, [sp, #16]
I 149.046243445 etm4_enable_hw: ffff800008ae1e34:
52800000 mov w0, #0x0 // #0
I 149.046243445 etm4_enable_hw: ffff800008ae1e38:
a8c27bfd ldp x29, x30, [sp], #32
I 149.046243445 etm4_enable_hw: ffff800008ae1e3c:
d50323bf autiasp
E 149.046243445 etm4_enable_hw: ffff800008ae1e40:
d65f03c0 ret
A ete_sysreg_write: ffff800008adfa18
..snip
I 149.05422547 panic: ffff800008096300:
a90363f7 stp x23, x24, [sp, #48]
I 149.05422547 panic: ffff800008096304:
6b00003f cmp w1, w0
I 149.05422547 panic: ffff800008096308:
3a411804 ccmn w0, #0x1, #0x4, ne // ne = any
N 149.05422547 panic: ffff80000809630c:
540001e0 b.eq ffff800008096348 <panic+0xe0> // b.none
I 149.05422547 panic: ffff800008096310:
f90023f9 str x25, [sp, #64]
E 149.05422547 panic: ffff800008096314:
97fe44ef bl ffff8000080276d0 <panic_smp_self_stop>
A panic: ffff80000809634c
I 149.05422547 panic: ffff80000809634c:
910102d5 add x21, x22, #0x40
I 149.05422547 panic: ffff800008096350:
52800020 mov w0, #0x1 // #1
E 149.05422547 panic: ffff800008096354:
94166b8b bl ffff800008631180 <bust_spinlocks>
N 149.054225518 bust_spinlocks: ffff800008631180:
340000c0 cbz w0, ffff800008631198 <bust_spinlocks+0x18>
I 149.054225518 bust_spinlocks: ffff800008631184:
f000a321 adrp x1, ffff800009a98000 <pbufs.0+0xbb8>
I 149.054225518 bust_spinlocks: ffff800008631188:
b9405c20 ldr w0, [x1, #92]
I 149.054225518 bust_spinlocks: ffff80000863118c:
11000400 add w0, w0, #0x1
I 149.054225518 bust_spinlocks: ffff800008631190:
b9005c20 str w0, [x1, #92]
E 149.054225518 bust_spinlocks: ffff800008631194:
d65f03c0 ret
A panic: ffff800008096358
Linu Cherian (7):
dt-bindings: arm: coresight-tmc: Add "memory-region" property
ccoresight: tmc-etr: Add support to use reserved trace memory
coresight: core: Add provision for panic callbacks
coresight: tmc: Enable panic sync handling
coresight: tmc: Add support for reading tracedata from previous boot
coresight: tmc: Stop trace capture on FlIn
coresight: etm4x: Configure ETM to trigger on panic
.../bindings/arm/arm,coresight-tmc.yaml | 9 +
drivers/hwtracing/coresight/coresight-core.c | 31 ++
.../coresight/coresight-etm4x-core.c | 17 +-
drivers/hwtracing/coresight/coresight-etm4x.h | 26 ++
drivers/hwtracing/coresight/coresight-priv.h | 1 +
.../hwtracing/coresight/coresight-tmc-core.c | 125 +++++++-
.../hwtracing/coresight/coresight-tmc-etf.c | 151 ++++++++-
.../hwtracing/coresight/coresight-tmc-etr.c | 286 +++++++++++++++++-
drivers/hwtracing/coresight/coresight-tmc.h | 39 +++
include/linux/coresight.h | 11 +
10 files changed, 688 insertions(+), 8 deletions(-)
--
2.40.1
Introduction of TPDM DSB subunit
DSB subunit is responsible for creating a dataset element, and is also
optionally responsible for packing it to fit multiple elements on a
single ATB transfer if possible in the configuration. The TPDM Core
Datapath requests timestamps be stored by the TPDA and then delivering
ATB sized data (depending on ATB width and element size, this could
be smaller or larger than a dataset element) to the ATB Mast FSM.
The DSB subunit must be configured prior to enablement. This series
adds support for TPDM to configure the configure DSB subunit.
Once this series patches are applied properly, the new tpdm nodes for
should be observed at the tpdm path /sys/bus/coresight/devices/tpdm*
which supports DSB subunit.
e.g.
root@qemuarm64:/sys/devices/platform/soc@0/6c08000.tpdm/tpdm1# ls -l
drwxr-xr-x 2 root root 0 Jan 1 00:00 connections
drwxr-xr-x 2 root root 0 Jan 1 00:00 dsb_edge
-rw-r--r-- 1 root root 4096 Jan 1 00:00 dsb_mode
drwxr-xr-x 2 root root 0 Jan 1 00:00 dsb_msr
drwxr-xr-x 2 root root 0 Jan 1 00:00 dsb_patt
-rw-r--r-- 1 root root 4096 Jan 1 00:00 dsb_patt_ts
-rw-r--r-- 1 root root 4096 Jan 1 00:00 dsb_patt_type
drwxr-xr-x 2 root root 0 Jan 1 00:00 dsb_trig_patt
-rw-r--r-- 1 root root 4096 Jan 1 00:00 dsb_trig_ts
-rw-r--r-- 1 root root 4096 Jan 1 00:00 dsb_trig_type
-rw-r--r-- 1 root root 4096 Jan 1 00:02 enable_source
--w------- 1 root root 4096 Jan 1 00:00 integration_test
drwxr-xr-x 2 root root 0 Jan 1 00:00 power
--w------- 1 root root 4096 Jan 1 00:02 reset_dataset
lrwxrwxrwx 1 root root 0 Apr 5 2021 subsystem -> ../../../../../bus/coresight
-rw-r--r-- 1 root root 4096 Apr 5 2021 uevent
-r--r--r-- 1 root root 4096 Jan 1 00:00 waiting_for_supplier
We can use the commands are similar to the below to configure the
TPDMs which support DSB subunit. Enable coresight sink first.
echo 1 > /sys/bus/coresight/devices/tmc_etf0/enable_sink
echo 1 > /sys/bus/coresight/devices/tpdm1/reset_dataset
echo 0x3 > /sys/bus/coresight/devices/tpdm1/dsb_edge/ctrl_idx
echo 0x1 > /sys/bus/coresight/devices/tpdm1/dsb_edge/ctrl_mask
echo 0x0 > /sys/bus/coresight/devices/tpdm1/dsb_edge/ctrl_val
echo 1 > /sys/bus/coresight/devices/tpdm1/dsb_patt_ts
echo 1 > /sys/bus/coresight/devices/tpdm1/dsb_patt_type
echo 0 > /sys/bus/coresight/devices/tpdm1/dsb_trig_ts
echo 0xFFFFFFFF > /sys/bus/coresight/devices/tpdm1/dsb_patt/tpmr5
echo 0xFFFFFFFF > /sys/bus/coresight/devices/tpdm1/dsb_trig_patt/xpr2
echo 1 > /sys/bus/coresight/devices/tpdm1/enable_source
TPDM_DSB commit tree:
https://git.codelinaro.org/clo/linux-kernel/coresight/-/tree/tpdm-dsb-v8https://git.codelinaro.org/clo/linux-kernel/coresight/-/commits/tpdm-dsb-v8
Changes in V8:
1. Refine the function "tpda_set_element_size" and rename it
to "tpda_get_element_size" in the patch#4.
-- Suzuki K Poulose
2. Refine the functioin "tpda_enable_port" in the patch#4.
-- Suzuki K Poulose
3. Write a helper to check if the TPDM has DSB dataset in the
patch#5.
-- Suzuki K Poulose
4. Move the function "tpdm_reset_datasets" to "datasets_setup"
to call in the patch#5.
-- Suzuki K Poulose
5. Refine the comment of DSB in "tpdm_drvdata" in the patch#5.
-- Suzuki K Poulose
6. Refine the comments in the documents for this patch series.
-- Suzuki K Poulose
7. Adjust the code alignment in this patch series.
-- Suzuki K Poulose
8. Combine the mode related functions to one in the patch#8.
-- Suzuki K Poulose
9. Refine the R/W functions of "dsb_mode" in the patch#8.
-- Suzuki K Poulose
10. Adjust the macros of mode in the TPDM header file in the
patch#8.
-- Suzuki K Poulose
11. Remove the unused code and fix the warnings in compiling
for the patch#9.
-- kernel test robot
12. Use the following sysfs nodes to read/set edge control
related value in the patch#9.
dsb_edge/
\- ctrl_idx -> Set the index number
\- ctrl_val -> Set the edge control value
\- ctrl_mask -> Set the edge control mask
\- edcr0 ... edcr15 -> Read the edge control value
\- edcmr0 ... edcmr7 -> Read the edge control mask
-- Suzuki K Poulose
13. Use the following sysfs nodes to read/set DSB trigger
pattern value and mask in the patch#10.
dsb_trig_patt/
\- xpr0 ... xpr15 -> (RW) Set/Get the value
\- xpmr0 ... xpmr7 -> (RW) Set/Get the mask
-- Suzuki K Poulose
14. Use the following sysfs nodes to read/set DSB pattern
value and mask in the patch#11.
dsb_patt/
\- tpr0 ... tpr15 -> (RW) Set/Get the value
\- tpmr0 ... tpmr7 -> (RW) Set/Get the mask
-- Suzuki K Poulose
15. Add "Acked-by" tag to the patch#12.
-- Rob Herring
16. Use the following sysfs nodes to read/set DSB MSR in
the patch#13.
dsb_msr/
\- msr0 ... msr31 -> (RW) Set/Get the value
-- Suzuki K Poulose
17. Create the maximal number of DSB MSR sysfs nodes if the
TPDM supports DSB MSR. Write the values set by user space to
the DSB MSR according to the number of MSR supported by the
TPDM.
-- Suzuki K Poulose
Changes in V7:
1. Since the "One value" limitation on SysFs file usage, add
the nodes to read/write the index number for configuring the
DSB TPDM. The following index number nodes are added.
"dsb_edge_ctrl_idx" in the patch #9
"dsb_trig_patt_idx" in the patch #10
"dsb_patt_idx" in the patch #11
"dsb_msr_idx" in the patch #13
-- Suzuki K Poulose
Changes in V6:
1. Align the code to fix the styling issue.
-- Suzuki K Poulose
Changes in V5:
1. Correct data type for DSB element size in dt-bindings patch.
2. Refine the recursive function "tpda_set_element_size".
-- Suzuki K Poulose
3. Get return value of the function "__tpda_enable" in
"tpda_enable".
-- Suzuki K Poulose
4. Refine the comments on "dsb_esize".
-- Suzuki K Poulose
5. Split the chage that introduce the subtype
"SUBTYPE_SOURCE_TPDM" to Coresight driver.
-- Suzuki K Poulose
6. Inline the trigger type setting to "tpdm_enable_dsb" simply.
-- Suzuki K Poulose
7. Split the change that remove the needless CS_{UN,}LOCK in
the function "tpdm_datasets_setup".
-- Suzuki K Poulose
8. Remove the disablement step in the reset node.
-- Suzuki K Poulose
9. Update the kernel version to 6.5 in the sysfs document.
-- Suzuki K Poulose
10. Remove the needless check in "tpdm_dsb_is_visible".
-- Suzuki K Poulose
11. Change the macro to mask the mode of DSB TPDM.
-- Suzuki K Poulose
12. Add a check to make sure "sysfs_emit_at" calling will not
cause overflow.
-- Suzuki K Poulose
13. Change the macro to get "edge_ctrl" value.
-- Suzuki K Poulose
14. Remove the needless comments in the sysfs document.
-- Suzuki K Poulose
15. Replace "TPDM_DSB_MAX_PATT" with "drvdata->dsb->msr_num" in
"dsb_msr_show".
-- Suzuki K Poulose
16. Update the check of MSR number in "dsb_msr_store".
-- Suzuki K Poulose
17. Write data to the MSR registers in the DSB TPDM enablement
function.
-- Suzuki K Poulose
Changes in V4:
1. Change the range of the property "qcom,dsb-element-size", and
change the type to enumeration.
-- Suzuki K Poulose, Krzysztof Kozlowski
2. Change dsb_esize from 32 bits to 8 bits.
-- Suzuki K Poulose
3. Update the function tpda_set_element_size since James has
updated the dependency series. Meanwhile, it will send out a
warning if it detects more than one TPDM from the same TPDA
input port.
-- Suzuki K Poulose
4. Add a source_sub_type for TPDM to distinguish TPDM from
the other coresight source.
-- Suzuki K Poulose
5. Return error if the element size is not configured on
devicetree in TPDA enablement.
-- Suzuki K Poulose
6. Move memory allocation from "tpdm_init_datasets" to
"tpdm_datasets_setup". Rename "tpdm_init_datasets" as
"tpdm_reset_datasets".
-- Suzuki K Poulose
7. Replace "coresight_disable" with "coresight_disable_source"
to disable the TPDM in resetting.
-- Suzuki K Poulose
8. Make sure "drvdata" is not NULL pointer before using it.
-- Suzuki K Poulose
9. Change "set_dsb_cycacc_mode" to "set_dsb_test_mode" since
cycle accurate mode is not supported on the current targets.
It is replaced by test mode.
10. Document the value of "dsb_mode".
-- Suzuki K Poulose
11. Macros are used to replace the formulas on dsb edge control
nodes.
-- Suzuki K Poulose
12. Document the values of "dsb_trig_patt_val" and
"dsb_trig_patt_mask".
-- Suzuki K Poulose
13. Combine two pattern related loops to one. And move DSB TIER
register configurations to the new function "set_dsb_tier".
-- Suzuki K Poulose
14. Rename the property "qcom,dsb_msr_num" to "qcom,dsb-msrs-num".
-- Suzuki K Poulose, Krzysztof Kozlowski
Changes in V3:
1. Move the property "qcom,dsb-element-size" to TPDM
devicetree and update the TPDM yaml file for this item.
-- Suzuki K Poulose
2. Add the error message when the DSB element size is not set to
32-bit or 64-bit. -- Suzuki K Poulose
3. Add more information to the comments of patch #3
-- Suzuki K Poulose
4. Combine the value updates to the TPDM_DSB_CR for TPDM.
-- Suzuki K Poulose
5. Remove the function "tpdm_datasets_alloc", and fold its code
to a new function "tpdm_init_datasets". It will complete the
initialization of TPDM. -- Suzuki K Poulose
6. Change the method of qualifying input values.
-- Suzuki K Poulose
7. Add the documentation of the new sysfs handles.
-- Suzuki K Poulose
8. Provide the separate handles for the "mode bits".
-- Suzuki K Poulose
Changes in V2:
1. Change the name of the property "qcom,dsb-elem-size" to
"qcom,dsb-element-size" -- Suzuki K Poulose
2. Update the TPDA yaml file for the item "qcom,dsb-elem-size".
-- Krzysztof Kozlowski
3. Add the full name of DSB in the description of the item
"qcom,dsb-elem-size". -- Rob Herring
Changes in V1:
1. Change the definition of the property "qcom,dsb-elem-size" from
"uint32-array" to "uint32-matrix". -- Krzysztof Kozlowski
2. Add the full name of DSB. -- Rob Herring
3. Deal with 2 entries in an iteration in TPDA driver. -- Suzuki K Poulose
4. Divide the function "tpdm_datasets_alloc" into two functions,
"tpdm_datasets_setup" and "tpdm_datasets_alloc".
5. Detecte the input string with the conventional semantics automatically,
and constrain the size of the input value. -- Suzuki K Poulose
6. Use the hook function "is_visible()" to hide the DSB related knobs if
the data sets are missing. -- Suzuki K Poulose
7. Use the macros "FIELD_GET" and "FIELD_PREP" to set the values.
-- Suzuki K Poulose
8. Update the definition of the macros in TPDM driver.
9. Update the comments of the values for the nodes which are for DSB
element creation and onfigure pattern match output. -- Suzuki K Poulose
10. Use API "sysfs_emit" to "replace scnprintf". -- Suzuki K Poulose
Tao Zhang (13):
coresight-tpdm: Remove the unnecessary lock
dt-bindings: arm: Add support for DSB element size
coresight-tpdm: Introduce TPDM subtype to TPDM driver
coresight-tpda: Add DSB dataset support
coresight-tpdm: Initialize DSB subunit configuration
coresight-tpdm: Add reset node to TPDM node
coresight-tpdm: Add nodes to set trigger timestamp and type
coresight-tpdm: Add node to set dsb programming mode
coresight-tpdm: Add nodes for dsb edge control
coresight-tpdm: Add nodes to configure pattern match output
coresight-tpdm: Add nodes for timestamp request
dt-bindings: arm: Add support for DSB MSR register
coresight-tpdm: Add nodes for dsb msr support
.../ABI/testing/sysfs-bus-coresight-devices-tpdm | 159 +++++
.../bindings/arm/qcom,coresight-tpdm.yaml | 20 +
drivers/hwtracing/coresight/coresight-core.c | 3 +
drivers/hwtracing/coresight/coresight-tpda.c | 126 +++-
drivers/hwtracing/coresight/coresight-tpda.h | 2 +
drivers/hwtracing/coresight/coresight-tpdm.c | 682 ++++++++++++++++++++-
drivers/hwtracing/coresight/coresight-tpdm.h | 165 +++++
include/linux/coresight.h | 1 +
8 files changed, 1136 insertions(+), 22 deletions(-)
--
2.7.4
This patch series is to improve timestamp handling in per-thread mode.
The current code doesn't validate timestamp and always return success for
per-thread mode, for a sane implementation, the first patch is to allow
validation timestamp tracing in per-thread mode.
The second patch is to respect timestamp option "--timestamp" or "-T",
when users set this option, the tool will automatically enable hardware
timestamp tracing in Arm CoreSight.
Leo Yan (2):
perf cs-etm: Validate timestamp tracing in per-thread mode
perf cs-etm: Respect timestamp option
tools/perf/arch/arm/util/cs-etm.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
--
2.34.1
I haven't done any meaningful work for a long while on Arm CoreSight and
it's unlikely I'll be able to do related work in the future.
Remove myself from the Arm CoreSight "Reviewers" list.
Signed-off-by: Leo Yan <leo.yan(a)linaro.org>
---
MAINTAINERS | 1 -
1 file changed, 1 deletion(-)
diff --git a/MAINTAINERS b/MAINTAINERS
index e0ad886d3163..342b8a3e19e3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2102,7 +2102,6 @@ N: digicolor
ARM/CORESIGHT FRAMEWORK AND DRIVERS
M: Suzuki K Poulose <suzuki.poulose(a)arm.com>
R: Mike Leach <mike.leach(a)linaro.org>
-R: Leo Yan <leo.yan(a)linaro.org>
L: coresight(a)lists.linaro.org (moderated for non-subscribers)
L: linux-arm-kernel(a)lists.infradead.org (moderated for non-subscribers)
S: Maintained
--
2.39.2
Cc: Sudeep
Hi Steve
On 28/08/2023 17:35, Steve Clevenger wrote:
>
> Hi Suzuki,
>
> On 8/27/2023 2:35 PM, Suzuki K Poulose wrote:
>> Hi Steve
>>
>> On 26/08/2023 01:14, Steve Clevenger wrote:
>>>
>>> Unfortunately, I tested with the original patch not [PATCH V2]. I've
>>> remedied this. My results below:
>>>
>>> [root@sut01sys-b212 linux]# cat
>>> /sys/devices/system/cpu/cpu123/ARMHC501\:23/tmc_etr35/buf_modes_available
>>> auto flat catu
>>> [root@sut01sys-b212 linux]# cat
>>> /sys/devices/system/cpu/cpu123/ARMHC501\:23/tmc_etr35/buf_mode_preferred
>>> auto
>>> [root@sut01sys-b212 linux]# echo "catu" >
>>> /sys/devices/system/cpu/cpu123/ARMHC501\:23/tmc_etr35/buf_mode_preferred
>>> [root@sut01sys-b212 linux]# cat
>>> /sys/devices/system/cpu/cpu123/ARMHC501\:23/tmc_etr35/buf_mode_preferred
>>> catu
>>>
>>> As with the V1 patch, auto defaults to catu.
>>>
>>> I expected to see tmc-sg (former default) as an available mode, but do
>>> not. As I recall, the buffer mode defaulted to ETR scatter-gather prior
>>> to this patch. Must this capability now be explicitly advertised? I've
>>> seen this done as "arm,scatter-gather" in device trees, but not used by
>>> Ampere. Perhaps someone can enlighten me.
>>
>> Yes, you must add that property to the TMC-ETR node (for both DT and
>> ACPI). In the past, almost all of the TMC-ETRs (except Juno board)
>> locked up the system while using the SG mode (due to the interconnect
>> issues, something to do with the transaction). Thus, we decided to
>> add a property explicitly enabling this for a given platform.
>>
>> When you mentioned, it was using TMC-ETR SG mode, how did you verify
>> this ? Please be aware that the table allocation code etc are shared
>> by both TMC-SG and CATU.
>>
>
> You might recall how this started. I had no way to test the CATU due to
> the order the ETR modes defaulted (Flat, ETR-SG, CATU). For test
> purposes, I programmatically swapped the ETR-SG/CATU order and could
> then verify CATU operation by the driver calling into CATU code. This
So, were you using the DT based boot for the above runs ?
> suggests Flat mode was bypassed, and the driver defaulted to ETR-SG
> prior to this hack. This didn't offer the user any control, hence my
> feature request. Note that most of the early Ampere self-hosted trace
> collection used ETR-SG. Now I can't select it.
>
> How is this property described in the ACPI? The "ACPI for CoreSight™ 1.1
> Platform Design Document" (DEN0067) doesn't describe this.
This is not specified in the ACPI platform design document. I can get
it fixed. Ideally we need a property describing that the scatter-gather
mode is safe to use.
DT uses "arm,scatter-gather" property [0] and this is what we now expect
in the ACPI based systems too.
https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bin…
Does it sound fine ?
Suzuki
>
> Thanks,
> Steve
>
>
>> Kind regards
>> Suzuki
>>
>>>
>>> Steve C.
>>>
>>> On 8/23/2023 4:10 PM, Steve Clevenger wrote:
>>>>
>>>> Here's some quick feedback. My system shows two modes available; auto
>>>> catu
>>>>
>>>> etr_buf_mode_current is writable. I expected to see tmc-sg (former
>>>> default) listed in etr_buf_modes_available but it doesn't show up.
>>>>
>>>> Note that both the auto and catu etr_buf_mode_current settings default
>>>> to catu. My understanding is auto should revert to the default behavior.
>>>> On my system the default was tmc-sg.
>>>>
>>>> More later.
>>>>
>>>> [root@sut01sys-b212 kernel]# cat
>>>> /sys/devices/system/cpu/cpu20/ARMHC501\:60/tmc_etr96/etr_buf_modes_available
>>>>
>>>> auto catu
>>>> [root@sut01sys-b212 kernel]# cat
>>>> /sys/devices/system/cpu/cpu20/ARMHC501\:60/tmc_etr96/etr_buf_mode_current
>>>> catu
>>>> [root@sut01sys-b212 kernel]# echo "catu" >
>>>> /sys/devices/system/cpu/cpu20/ARMHC501\:60/tmc_etr96/etr_buf_mode_current
>>>> [root@sut01sys-b212 kernel]# cat
>>>> /sys/devices/system/cpu/cpu20/ARMHC501\:60/tmc_etr96/etr_buf_mode_current
>>>> catu
>>>>
>>>> Steve C.
>>>>
>>>>
>>>> On 8/21/2023 12:40 PM, Steve Clevenger wrote:
>>>>>
>>>>> Hi Suzuki,
>>>>>
>>>>> I may be able to test it this week. You've already pointed me at the
>>>>> patch thread(s). The main holdup is I need to merge the 6.6 pending
>>>>> platform work in order to use the Ampere ACPI. I couldn't get these
>>>>> patches to apply directly to 6.4 last I tried.
>>>>>
>>>>> Steve C.
>>>>>
>>>>> On 8/18/2023 2:39 AM, Suzuki K Poulose wrote:
>>>>>> Cc: Steve
>>>>>>
>>>>>> Steve,
>>>>>>
>>>>>> Are you able to test this with CATU ?
>>>>>>
>>>>>>
>>>>>> On 18/08/2023 09:21, Anshuman Khandual wrote:
>>>>>>> Currently TMC-ETR automatically selects the buffer mode from all
>>>>>>> available
>>>>>>> methods in the following sequentially fallback manner - also in that
>>>>>>> order.
>>>>>>>
>>>>>>> 1. FLAT mode with or without IOMMU
>>>>>>> 2. TMC-ETR-SG (scatter gather) mode when available
>>>>>>> 3. CATU mode when available
>>>>>>>
>>>>>>> But this order might not be ideal for all situations. For example if
>>>>>>> there
>>>>>>> is a CATU connected to ETR, it may be better to use TMC-ETR scatter
>>>>>>> gather
>>>>>>> method, rather than CATU. But hard coding such order changes will
>>>>>>> prevent
>>>>>>> us from testing or using a particular mode. This change provides
>>>>>>> following
>>>>>>> new sysfs tunables for the user to control TMC-ETR buffer mode
>>>>>>> explicitly,
>>>>>>> if required. This adds following new sysfs files for buffer mode
>>>>>>> selection
>>>>>>> purpose explicitly in the user space.
>>>>>>>
>>>>>>> /sys/bus/coresight/devices/tmc_etr<N>/buf_modes_available
>>>>>>> /sys/bus/coresight/devices/tmc_etr<N>/buf_mode_preferred
>>>>>>>
>>>>>>> $ cat buf_modes_available
>>>>>>> auto flat tmc-sg catu ------------------> Supported TMC-ETR buffer
>>>>>>> modes
>>>>>>>
>>>>>>> $ echo catu > buf_mode_preferred -------> Explicit buffer mode
>>>>>>> request
>>>>>>>
>>>>>>> But explicit user request has to be within supported ETR buffer modes
>>>>>>> only.
>>>>>>> These sysfs interface files are exclussive to ETR, and hence these
>>>>>>> are
>>>>>>> not
>>>>>>> available for other TMC devices such as ETB or ETF etc.
>>>>>>>
>>>>>>> A new auto' mode (i.e ETR_MODE_AUTO) has been added to help fallback
>>>>>>> to the
>>>>>>> existing default behaviour, when user provided preferred buffer mode
>>>>>>> fails.
>>>>>>> ETR_MODE_FLAT and ETR_MODE_AUTO are always available as preferred
>>>>>>> modes.
>>>>>>>
>>>>>>> Cc: Suzuki K Poulose <suzuki.poulose(a)arm.com>
>>>>>>> Cc: Mike Leach <mike.leach(a)linaro.org>
>>>>>>> Cc: James Clark <james.clark(a)arm.com>
>>>>>>> Cc: Leo Yan <leo.yan(a)linaro.org>
>>>>>>> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com>
>>>>>>> Cc: coresight(a)lists.linaro.org
>>>>>>> Cc: linux-arm-kernel(a)lists.infradead.org
>>>>>>> Cc: linux-kernel(a)vger.kernel.org
>>>>>>> Signed-off-by: Anshuman Khandual <anshuman.khandual(a)arm.com>
>>>>>>> ---
>>>>>>> This applies on v6.5-rc6
>>>>>>>
>>>>>>> Changes in V2:
>>>>>>>
>>>>>>> - Renamed sysfs file etr_buf_modes_available as buf_modes_available
>>>>>>> - Renamed sysfs file buf_mode_current as buf_mode_preferred
>>>>>>> - Renamed etr_supports_flat_mode() as etr_can_use_flat_mode()
>>>>>>> - Renamed coresight_tmc_groups[] as coresight_etf_groups[]
>>>>>>> - Reused coresight_tmc_group[] for trigger_cntr and buffer_size
>>>>>>> - Fallback trying ETR_MODE_AUTO when user preferred mode fails
>>>>>>> - Moved ETR sysfs details into coresight-tmc-etr.c
>>>>>>> - Dropped etr_can_use_flat_mode() check while offering ETR_MODE_FLAT
>>>>>>> in sysfs
>>>>>>> - Moved struct etr_buf_hw inside coresight-tmc-etr.c
>>>>>>> - Moved get_etr_buf_hw() and etr_can_use_flat_mode() inside
>>>>>>> coresight-tmc-etr.c
>>>>>>> - Updated month in
>>>>>>> Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc
>>>>>>>
>>>>>>> Changes in V1:
>>>>>>>
>>>>>>> https://lore.kernel.org/all/20230728084837.276551-1-anshuman.khandual@arm.c…
>>>>>>>
>>>>>>> .../testing/sysfs-bus-coresight-devices-tmc | 16 +++
>>>>>>> .../hwtracing/coresight/coresight-tmc-core.c | 15 ++-
>>>>>>> .../hwtracing/coresight/coresight-tmc-etr.c | 111
>>>>>>> ++++++++++++++++--
>>>>>>> drivers/hwtracing/coresight/coresight-tmc.h | 3 +
>>>>>>> 4 files changed, 131 insertions(+), 14 deletions(-)
>>>>>>
>>>>>>
>>>>>> Looks good to me.
>>>>>>
>>>>>> Suzuki
>>>>>>
>>>>>>
>>
These are remaining coresight patches after fixing the merge conflict which
applies on coresight/next coresight-next-v6.6.
Changes in V6:
- Fixed te merge conflict
Changes in V5:
https://lore.kernel.org/all/20230817055405.249630-1-anshuman.khandual@arm.c…
- Detected zeroed parsed GSI as a mismatch but handled all zero scenario
- Changed condition check from 'if (ret < 0)' into a 'if (ret)'
- Dropped pr_warn() message after platform_device_register()
Changes in V4:
https://lore.kernel.org/all/20230808082247.383405-1-anshuman.khandual@arm.c…
- Added in-code comment for arm_trbe_device_probe()
- Reverted back using IS_ENABLED() for SPE PMU platform device
- Replaced #ifdef with IS_ENABLED() for TRBE platform device
- Protected arm_trbe_acpi_match with ACPI_PTR() - preventing a build failure
when CONFIG_ACPI is not enabled
- Added __maybe_unused for arm_acpi_register_pmu_device() and dropped config
checks with IS_ENABLED()
Changes in V3:
https://lore.kernel.org/all/20230803055652.1322801-1-anshuman.khandual@arm.…
- Changed ARMV8_TRBE_PDEV_NAME from "arm-trbe-acpi" into "arm,trbe"
- Dropped local variable 'matched'
- Replaced 'matched' with 'valid gsi' as being already matched once
- Moved find_acpi_cpu_topology_hetero_id() outside conditional check
Changes in V2:
https://lore.kernel.org/all/20230801094052.750416-1-anshuman.khandual@arm.c…
- Refactored arm_spe_acpi_register_device() in a separate patch
- Renamed trbe_acpi_resources as trbe_resources
- Renamed trbe_acpi_dev as trbe_dev
Changes in V1:
https://lore.kernel.org/all/20230728112733.359620-1-anshuman.khandual@arm.c…
Cc: Sami Mujawar <sami.mujawar(a)arm.com>
Cc: Catalin Marinas <catalin.marinas(a)arm.com>
Cc: Will Deacon <will(a)kernel.org>
Cc: Mark Rutland <mark.rutland(a)arm.com>
Cc: Suzuki K Poulose <suzuki.poulose(a)arm.com>
Cc: Mike Leach <mike.leach(a)linaro.org>
Cc: Leo Yan <leo.yan(a)linaro.org>
Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com>
Cc: James Clark <james.clark(a)arm.com>
Cc: coresight(a)lists.linaro.org
Cc: linux-arm-kernel(a)lists.infradead.org
Cc: linux-kernel(a)vger.kernel.org
Anshuman Khandual (2):
coresight: trbe: Add a representative coresight_platform_data for TRBE
coresight: trbe: Enable ACPI based TRBE devices
drivers/hwtracing/coresight/coresight-trbe.c | 23 ++++++++++++++++++--
drivers/hwtracing/coresight/coresight-trbe.h | 2 ++
2 files changed, 23 insertions(+), 2 deletions(-)
--
2.25.1
Hi Yabin
On 29/08/2023 22:16, Yabin Cui wrote:
>> How can this be enabled ? Why not enable it before probing the ETR ?
> How can a user know if this has been done or not ?
>
> Pixel devices (like Pixel 6, 7) support enabling some debugging features
> (including granting non-secure access to ETM/ETR) even on devices with
> secure boot. It is only used internally and has strict requirements,
> needing to connect to a server to verify identification after booting.
> So it can't be established when probing ETR at device boot time.
Are you not able to build the coresight drivers as modules and load
them after the device has been authenticated and NS access enabled ?
Running a trace session without NS access enabled on a normal device
would be asking for trouble in the "normal world".
Suzuki
>
>
> On Sun, Aug 27, 2023 at 2:37 PM Suzuki K Poulose <suzuki.poulose(a)arm.com> wrote:
>>
>> On 26/08/2023 00:39, Yabin Cui wrote:
>>> Because the non-secure access can be enabled later on some devices.
>>
>> How can this be enabled ? Why not enable it before probing the ETR ?
>> How can a user know if this has been done or not ? It is asking for
>> trouble to continue without this.
>>
>> Suzuki
>>
>>>
>>> Signed-off-by: Yabin Cui <yabinc(a)google.com>
>>> ---
>>> drivers/hwtracing/coresight/coresight-tmc-core.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
>>> index c106d142e632..5ebfd12b627b 100644
>>> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
>>> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
>>> @@ -370,7 +370,7 @@ static int tmc_etr_setup_caps(struct device *parent, u32 devid, void *dev_caps)
>>> struct tmc_drvdata *drvdata = dev_get_drvdata(parent);
>>>
>>> if (!tmc_etr_has_non_secure_access(drvdata))
>>> - return -EACCES;
>>> + dev_warn(parent, "TMC ETR doesn't have non-secure access\n");
>>>
>>> /* Set the unadvertised capabilities */
>>> tmc_etr_init_caps(drvdata, (u32)(unsigned long)dev_caps);
>>