This series enables future IP trace features Embedded Trace Extension (ETE)
and Trace Buffer Extension (TRBE). This series depends on the ETM system
register instruction support series [0] and the v8.4 Self hosted tracing
support series (Jonathan Zhou) [1]. The tree is available here [2] for
quick access.
ETE is the PE (CPU) trace unit for CPUs, implementing future architecture
extensions. ETE overlaps with the ETMv4 architecture, with additions to
support the newer architecture features and some restrictions on the
supported features w.r.t ETMv4. The ETE support is added by extending the
ETMv4 driver to recognise the ETE and handle the features as exposed by the
TRCIDRx registers. ETE only supports system instructions access from the
host CPU. The ETE could be integrated with a TRBE (see below), or with the
legacy CoreSight trace bus (e.g, ETRs). Thus the ETE follows same firmware
description as the ETMs and requires a node per instance.
Trace Buffer Extensions (TRBE) implements a per CPU trace buffer, which is
accessible via the system registers and can be combined with the ETE to
provide a 1x1 configuration of source & sink. TRBE is being represented
here as a CoreSight sink. Primary reason is that the ETE source could work
with other traditional CoreSight sink devices. As TRBE captures the trace
data which is produced by ETE, it cannot work alone.
TRBE representation here have some distinct deviations from a traditional
CoreSight sink device. Coresight path between ETE and TRBE are not built
during boot looking at respective DT or ACPI entries. Instead TRBE gets
checked on each available CPU, when found gets connected with respective
ETE source device on the same CPU, after altering its outward connections.
ETE TRBE path connection lasts only till the CPU is online. But ETE-TRBE
coupling/decoupling method implemented here is not optimal and would be
reworked later on.
Unlike traditional sinks, TRBE can generate interrupts to signal including
many other things, buffer got filled. The interrupt is a PPI and should be
communicated from the platform. DT or ACPI entry representing TRBE should
have the PPI number for a given platform. During perf session, the TRBE IRQ
handler should capture trace for perf auxiliary buffer before restarting it
back. System registers being used here to configure ETE and TRBE could be
referred in the link below.
https://developer.arm.com/docs/ddi0601/g/aarch64-system-registers.
This adds another change where CoreSight sink device needs to be disabled
before capturing the trace data for perf in order to avoid race condition
with another simultaneous TRBE IRQ handling. This might cause problem with
traditional sink devices which can be operated in both sysfs and perf mode.
This needs to be addressed correctly. One option would be to move the
update_buffer callback into the respective sink devices. e.g, disable().
This series is primarily looking from some early feed back both on proposed
design and its implementation. It acknowledges, that it might be incomplete
and will have scopes for improvement.
Things todo:
- Improve ETE-TRBE coupling and decoupling method
- Improve TRBE IRQ handling for all possible corner cases
- Implement sysfs based trace sessions
[0] https://lore.kernel.org/linux-arm-kernel/20201028220945.3826358-1-suzuki.po…
[1] https://lore.kernel.org/linux-arm-kernel/1600396210-54196-1-git-send-email-…
[2] https://gitlab.arm.com/linux-arm/linux-skp/-/tree/coresight/etm/v8.4-self-h…
Anshuman Khandual (6):
arm64: Add TRBE definitions
coresight: sink: Add TRBE driver
coresight: etm-perf: Truncate the perf record if handle has no space
coresight: etm-perf: Disable the path before capturing the trace data
coresgith: etm-perf: Connect TRBE sink with ETE source
dts: bindings: Document device tree binding for Arm TRBE
Suzuki K Poulose (5):
coresight: etm-perf: Allow an event to use different sinks
coresight: Do not scan for graph if none is present
coresight: etm4x: Add support for PE OS lock
coresight: ete: Add support for sysreg support
coresight: ete: Detect ETE as one of the supported ETMs
.../devicetree/bindings/arm/coresight.txt | 3 +
Documentation/devicetree/bindings/arm/trbe.txt | 20 +
Documentation/trace/coresight/coresight-trbe.rst | 36 +
arch/arm64/include/asm/sysreg.h | 51 ++
drivers/hwtracing/coresight/Kconfig | 11 +
drivers/hwtracing/coresight/Makefile | 1 +
drivers/hwtracing/coresight/coresight-etm-perf.c | 85 ++-
drivers/hwtracing/coresight/coresight-etm-perf.h | 4 +
drivers/hwtracing/coresight/coresight-etm4x-core.c | 144 +++-
drivers/hwtracing/coresight/coresight-etm4x.h | 64 +-
drivers/hwtracing/coresight/coresight-platform.c | 9 +-
drivers/hwtracing/coresight/coresight-trbe.c | 768 +++++++++++++++++++++
drivers/hwtracing/coresight/coresight-trbe.h | 525 ++++++++++++++
include/linux/coresight.h | 2 +
14 files changed, 1680 insertions(+), 43 deletions(-)
create mode 100644 Documentation/devicetree/bindings/arm/trbe.txt
create mode 100644 Documentation/trace/coresight/coresight-trbe.rst
create mode 100644 drivers/hwtracing/coresight/coresight-trbe.c
create mode 100644 drivers/hwtracing/coresight/coresight-trbe.h
--
2.7.4
Hi all,
[ + CoreSight Mailing List ]
On the mainlne kernel with the latest commit 407ab579637c
"Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm",
the perf cs-etm testing fails.
I found the perf cs-etm testing itself has a typo issue and a regression
introduced by Perf tool in the recent mainline kernel, so I sent out the
two patches for fixing the related issues [1].
Even after applying these two fixings for the testing script, I still
observe the etm testing failure with snapshot mode. I manully checked
the perf data and confirmed the perf data contains the raw trace data
for snapshot (so 'perf script -D' can work well), but it fails to
generate any branch samples, so the command 'perf script' will not
output any samples.
Seems to me, this issue is more likely related with driver or Perf
tool's common code change but not the testing itself; Before I proceed
to use 'git bisect' to narrow down the snapshot mode failure, if you
have any idea for fixing this issue, please let me know. Otherwise, I
will dig into this issue and keep posted.
Thanks,
Leo
[1] https://lore.kernel.org/patchwork/patch/1336053/
__always_inline can cause build error on musl libc. The fix patch has
submitted but not merged yet[1]. To build perf tool with musl libc,
<linux/stddef.h> inclusion is necessary and it should be included before
perf_event.h.
from /usr/include/linux/byteorder/little_endian.h:13,
from /usr/include/asm/byteorder.h:23,
from tools/include/uapi/linux/perf_event.h:20,
from arch/arm64/util/../../arm/util/pmu.c:9:
/usr/include/linux/swab.h:171:8: error: unknown type name '__always_inline'
171 | static __always_inline __u16 __swab16p(const __u16 *p)
| ^~~~~~~~~~~~~~~
[1]: https://lkml.org/lkml/2018/9/13/78
Cc: Mathieu Poirier <mathieu.poirier(a)linaro.org>
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: John Garry <john.garry(a)huawei.com>
Cc: Will Deacon <will(a)kernel.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: Arnaldo Carvalho de Melo <acme(a)kernel.org>
Cc: Mark Rutland <mark.rutland(a)arm.com>
Cc: Jiri Olsa <jolsa(a)redhat.com>
Cc: Namhyung Kim <namhyung(a)kernel.org>
Cc: Khem Raj <raj.khem(a)gmail.com>
Signed-off-by: Chanho Park <chanho61.park(a)samsung.com>
---
tools/perf/arch/arm/util/pmu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/tools/perf/arch/arm/util/pmu.c b/tools/perf/arch/arm/util/pmu.c
index bbc297a7e2e3..4c0357e8c0ab 100644
--- a/tools/perf/arch/arm/util/pmu.c
+++ b/tools/perf/arch/arm/util/pmu.c
@@ -6,6 +6,9 @@
#include <string.h>
#include <linux/coresight-pmu.h>
+#if !defined(__GLIBC__)
+#include <linux/stddef.h>
+#endif
#include <linux/perf_event.h>
#include <linux/string.h>
--
2.23.0
CoreSight ETMv4.4 obsoletes memory mapped access to ETM and
mandates the system instructions for registers.
This also implies that they may not be on the amba bus.
Right now all the CoreSight components are accessed via memory
map. Also, we have some common routines in coresight generic
code driver (e.g, CS_LOCK, claim/disclaim), which assume the
mmio. In order to preserve the generic algorithms at a single
place and to allow dynamic switch for ETMs, this series introduces
an abstraction layer for accessing a coresight device. It is
designed such that the mmio access are fast tracked (i.e, without
an indirect function call).
This will also help us to get rid of the driver+attribute specific
sysfs show/store routines and replace them with a single routine
to access a given register offset (which can be embedded in the
dev_ext_attribute). This is not currently implemented in the series,
but can be achieved.
Further we switch the generic routines to work with the abstraction.
With this in place, we refactor the etm4x code a bit to allow for
supporting the system instructions with very little new code. The
changes also switch to using the system instructions by default
even when we may have an MMIO.
We use TRCDEVARCH for the detection of the ETM component, which
is a standard register as per CoreSight architecture, rather than
the etm specific id register TRCIDR1. This is for making sure
that we are able to detect the ETM via system instructions accurately,
when the the trace unit could be anything (etm or a custom trace unit).
To keep the backward compatibility for any existing broken
impelementation which may not implement TRCDEVARCH, we fall back to TRCIDR1.
Also this covers us for the changes in the future architecture [0].
Also, v8.4 self-hosted tracing extensions (coupled with ETMv4.4) adds
new filtering registers for trace by exception level. So on a v8.4
system, with Trace Filtering support, without the appropriate
programming of the Trace filter registers (TRFCR_ELx), tracing
will not be enabled. This series also includes the TraceFiltering
support to cover the ETM-v4.4 support.
The series has been mildly tested on a model for system instructions.
I would really appreciate any testing on real hardware.
Applies on coresight/next.
[0] https://developer.arm.com/docs/ddi0601/g/aarch64-system-registers/trcidr1
Known issues:
Checkpatch failure for "coresight: etm4x: Add sysreg access helpers" :
ERROR: Macros with complex values should be enclosed in parentheses
#121: FILE: drivers/hwtracing/coresight/coresight-etm4x.h:153:
+#define CASE_READ(res, x) \
+ case (x): { (res) = read_etm4x_sysreg_const_offset((x)); break; }
I don't know a way to fix the warning without loosing the code
readability, which I believe is crucial for such a construct.
Changes since v3:
- Device tree compatible changed to etm4x
- Use etm4x_** instead of generalizing etm_ in etm4x driver.
- Added v8.4 self hosted trace support patches, reworked
from Jonathan's series.
- Dropped queued patches.
- Expose TRCDEVARCH via trcidr, as this will be needed for
the userspace tools to determine the trace major/minor
arch versions.
- Remove csa argument to read()/write() (Mathieu)
- Fix secure exception mask calculation (Mathieu)
- Fix various coding style comments (Mathieu)
(See individual patches for change log)
Changes since V2:
- Several fixes to the ETM register accesses. Access a register
when it is present.
- Add support for TRCIDR3.NUMPROCS for v4.2+
- Drop OS lock detection. Use software lock only in case of mmio.
- Fix issues with the Exception level masks (Mike Leach)
- Fall back to using TRCIDR1 when TRCDEVARCH is not "present"
- Use a generic notion of ETM architecture (rather than using
the encoding as in registers)
- Fixed some checkpatch issues.
- Changed the dts compatible string to "arm,coresight-etm-sysreg"
(Mike Leach)
Changes since V1:
- Flip the switch for iomem from no_iomem to io_mem in csdev_access.
- Split patches for claim/disclaim and CS_LOCK/UNLOCK conversions.
- Move device access initialisation for etm4x to the target CPU
- Cleanup secure exception level mask handling.
- Switch to use TRCDEVARCH for ETM component discovery. This
is for making
- Check the availability of OS/Software Locks before using them.
Jonathan Zhou (2):
arm64: Add TRFCR_ELx definitions
coresight: Add support for v8.4 SelfHosted tracing
Suzuki K Poulose (23):
coresight: etm4x: Handle access to TRCSSPCICRn
coresight: etm4x: Skip accessing TRCPDCR in save/restore
coresight: Introduce device access abstraction
coresight: tpiu: Prepare for using coresight device access abstraction
coresight: Convert coresight_timeout to use access abstraction
coresight: Convert claim/disclaim operations to use access wrappers
coresight: etm4x: Always read the registers on the host CPU
coresight: etm4x: Convert all register accesses
coresight: etm4x: Add commentary on the registers
coresight: etm4x: Add sysreg access helpers
coresight: etm4x: Define DEVARCH register fields
coresight: etm4x: Check for Software Lock
coresight: etm4x: Cleanup secure exception level masks
coresight: etm4x: Clean up exception level masks
coresight: etm4x: Handle ETM architecture version
coresight: etm4x: Detect access early on the target CPU
coresight: etm4x: Use TRCDEVARCH for component discovery
coresight: etm4x: Expose trcdevarch via trcidr
coresight: etm4x: Add necessary synchronization for sysreg access
coresight: etm4x: Detect system instructions support
coresight: etm4x: Refactor probing routine
coresight: etm4x: Add support for sysreg only devices
dts: bindings: coresight: ETM system register access only units
.../devicetree/bindings/arm/coresight.txt | 5 +-
arch/arm64/include/asm/sysreg.h | 11 +
drivers/hwtracing/coresight/coresight-catu.c | 12 +-
drivers/hwtracing/coresight/coresight-core.c | 122 ++-
.../hwtracing/coresight/coresight-cti-core.c | 18 +-
drivers/hwtracing/coresight/coresight-etb10.c | 10 +-
.../coresight/coresight-etm3x-core.c | 9 +-
.../coresight/coresight-etm4x-core.c | 771 +++++++++++-------
.../coresight/coresight-etm4x-sysfs.c | 46 +-
drivers/hwtracing/coresight/coresight-etm4x.h | 498 ++++++++++-
.../hwtracing/coresight/coresight-funnel.c | 7 +-
.../coresight/coresight-replicator.c | 13 +-
drivers/hwtracing/coresight/coresight-stm.c | 4 +-
.../hwtracing/coresight/coresight-tmc-core.c | 16 +-
.../hwtracing/coresight/coresight-tmc-etf.c | 10 +-
.../hwtracing/coresight/coresight-tmc-etr.c | 4 +-
drivers/hwtracing/coresight/coresight-tpiu.c | 31 +-
include/linux/coresight.h | 227 +++++-
18 files changed, 1386 insertions(+), 428 deletions(-)
--
2.24.1
When the ETR is used in perf mode with a larger buffer (configured
via sysfs or the default size of 1M) than the perf aux buffer size,
we end up inserting the barrier packet at the wrong offset, while
moving the offset forward. i.e, instead of the "new moved offset",
we insert it at the current hardware buffer offset. These packets
will not be visible as they are never copied and could lead to
corruption in the trace decoding side, as the decoder is not aware
that it needs to reset the decoding.
Fixes: ec13c78d7b45 ("coresight: tmc-etr: Add barrier packets when moving offset forward")
Reported-by: Al Grant <al.grant(a)arm.com>
Tested-by: Mike Leach <mike.leach(a)arm.com>
Cc: Mathieu Poirier <mathieu.poirier(a)linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose(a)arm.com>
---
drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index a31a4d7ae25e..bf5230e39c5b 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1552,7 +1552,7 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
/* Insert barrier packets at the beginning, if there was an overflow */
if (lost)
- tmc_etr_buf_insert_barrier_packet(etr_buf, etr_buf->offset);
+ tmc_etr_buf_insert_barrier_packet(etr_buf, offset);
tmc_etr_sync_perf_buffer(etr_perf, offset, size);
/*
--
2.24.1