'timestamp' is currently 1 bit wide for on/off. To enable setting
different intervals, extend it to 4 bits wide. Keep the old bit position
for backward compatibility ("deprecated_timestamp") but don't publish in
the format/ folder. It will be removed from the documentation and can be
removed completely after enough time has passed.
ETM3x doesn't support different intervals, so validate that the value is
either 0 or 1.
Tools that read the bit positions from the format/ folder will continue
to work as before, setting either 0 or 1 for off/on. Tools that
incorrectly didn't do this and set the ETM_OPT_TS bit directly will also
continue to work because that old bit is still checked.
This avoids adding a second timestamp attribute for setting the
interval. This would be awkward to use because tools would have to be
updated to ensure that the timestamps are always enabled when an
interval is set, and the driver would have to validate that both options
are provided together. All this does is implement the semantics of a
single enum but spread over multiple fields.
Reviewed-by: Leo Yan <leo.yan@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Tested-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251128-james-cs-syncfreq-v8-12-4d319764cc58@linaro.org
Timestamps are currently emitted at the maximum rate possible, which is
much too frequent for most use cases. In the next commit, the timestamp
field will be widened to take a value, so set the interval using the
value now. Granular control is not required, so save space in the config
by interpreting it as 2 ^ timestamp. And then 4 bits (0 - 15) will be
enough to set the interval to be larger than the existing SYNC timestamp
interval.
No sysfs mode support is needed for this attribute because counter
generated timestamps are only configured for Perf mode.
Reviewed-by: Leo Yan <leo.yan@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251128-james-cs-syncfreq-v8-11-4d319764cc58@linaro.org
Currently we're programming attr->config directly into ETMCR after some
validation. This obscures which fields are being used, and also makes it
impossible to move fields around or use other configN fields in the
future.
Improve it by only reading the fields that are valid and then setting
the appropriate ETMCR bits based on each one.
The ETMCR_CTXID_SIZE part can be removed as it was never a valid option
because it's not in ETM3X_SUPPORTED_OPTIONS.
Reviewed-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Tested-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251128-james-cs-syncfreq-v8-6-4d319764cc58@linaro.org
Remove some of the magic numbers and try to clarify some of the
documentation so it's clearer how this sets up the timestamp interval.
Return errors directly instead of jumping to out and returning ret,
nothing needs to be cleaned up at the end and it only obscures the flow
and return value.
Add utilities for programming resource selectors that do compile time
checks for constants or WARN_ONs for non-constant values. FIELD_PREP
includes compile time checks so we only need to add an additional
BUILD_BUG_ON for resource == 0 in pair mode.
Tested-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251128-james-cs-syncfreq-v8-3-4d319764cc58@linaro.org
Pull char/misc/IIO driver updates from Greg KH:
"Here is the big set of char/misc/iio driver updates for 6.19-rc1. Lots
of stuff in here including:
- lots of IIO driver updates, cleanups, and additions
- large interconnect driver changes as they get converted over to a
dynamic system of ids
- coresight driver updates
- mwave driver updates
- binder driver updates and changes
- comedi driver fixes now that the fuzzers are being set loose on
them
- nvmem driver updates
- new uio driver addition
- lots of other small char/misc driver updates, full details in the
shortlog
All of these have been in linux-next for a while now"
* tag 'char-misc-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (304 commits)
char: applicom: fix NULL pointer dereference in ac_ioctl
hangcheck-timer: fix coding style spacing
hangcheck-timer: Replace %Ld with %lld
hangcheck-timer: replace printk(KERN_CRIT) with pr_crit
uio: Add SVA support for PCI devices via uio_pci_generic_sva.c
dt-bindings: slimbus: fix warning from example
intel_th: Fix error handling in intel_th_output_open
misc: rp1: Fix an error handling path in rp1_probe()
char: xillybus: add WQ_UNBOUND to alloc_workqueue users
misc: bh1770glc: use pm_runtime_resume_and_get() in power_state_store
misc: cb710: Fix a NULL vs IS_ERR() check in probe()
mux: mmio: Add suspend and resume support
virt: acrn: split acrn_mmio_dev_res out of acrn_mmiodev
greybus: gb-beagleplay: Fix timeout handling in bootloader functions
greybus: add WQ_PERCPU to alloc_workqueue users
char/mwave: drop typedefs
char/mwave: drop printk wrapper
char/mwave: remove printk tracing
char/mwave: remove unneeded fops
char/mwave: remove MWAVE_FUTZ_WITH_OTHER_DEVICES ifdeffery
...
intel_th_output_open() calls bus_find_device_by_devt() which
internally increments the device reference count via get_device(), but
this reference is not properly released in several error paths. When
device driver is unavailable, file operations cannot be obtained, or
the driver's open method fails, the function returns without calling
put_device(), leading to a permanent device reference count leak. This
prevents the device from being properly released and could cause
resource exhaustion over time.
Found by code review.
Cc: stable <stable@kernel.org>
Fixes: 39f4034693 ("intel_th: Add driver infrastructure for Intel(R) Trace Hub devices")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Link: https://patch.msgid.link/20251112091723.35963-1-make24@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suzuki writes:
coresight: Updates for Linux v6.19
The changes for Linux v6.19 include :
- Support for static TPDM
- Fixes to TMC-ETR with CATU where buffer wasn't available to CATU in perf mode
- Clean ups to the component operations to accept coresight_path
- Fixes to the ETM4x/ETM3x driver
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
* tag 'coresight-next-v6.19' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/coresight/linux:
coresight: etm4x: Remove the state_needs_restore flag
coresight: etm4x: Remove the redundant DSB
coresight: etm4x: Properly control filter in CPU idle with FEAT_TRF
coresight: etm4x: Add context synchronization before enabling trace
coresight: etm4x: Correct polling IDLE bit
coresight: etm3x: Always set tracer's device mode on target CPU
coresight: etm4x: Always set tracer's device mode on target CPU
coresight: Change device mode to atomic type
coresight: change the sink_ops to accept coresight_path
coresight: change helper_ops to accept coresight_path
coresight: tmc: add the handle of the event to the path
coresight: tpdm: remove redundant check for drvdata
coresight: tpdm: add static tpdm support
dt-bindings: arm: document the static TPDM compatible
coresight: ETR: Fix ETR buffer use-after-free issue
When the restore flow is invoked, it means no error occurred during the
save phase. Otherwise, if any errors happened while saving the context,
the function would return an error and abort the suspend sequence.
Therefore, the state_needs_restore flag is unnecessary. The save and
restore functions are changed to check two conditions:
1) The global flag pm_save_enable is SELF_HOSTED mode;
2) The device is in active mode (non DISABLED).
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251111-arm_coresight_power_management_fix-v6-8-f55553b6c8b3@arm.com
As recommended in section 4.3.7 "Synchronization when using the
memory-mapped interface" of ARM IHI0064H.b:
When using the memory-mapped interface to program the trace unit, the
trace analyzer must ensure that writes have completed, to ensure that
the trace unit is fully programmed and either enabled or disabled.
To ensure writes have completed, the trace analyzer can do ...
If the memory marked is as Device-nGnRE or stronger, read back the
value of any register in the trace unit. This relies on peripheral
coherence order defined in the Arm architecture.
Polling TRCSTATR ensures the previous write has completed. Therefore,
removes the redundant DSB barrier in the enabling flow.
Update the comment in the disable flow for consistency.
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251111-arm_coresight_power_management_fix-v6-7-f55553b6c8b3@arm.com
If a CPU supports FEAT_TRF, as described in the section K5.5 "Context
switching", Arm ARM (ARM DDI 0487 L.a), it defines a flow to prohibit
program-flow trace, execute a TSB CSYNC instruction for flushing,
followed by clearing TRCPRGCTLR.EN bit.
To restore the state, the reverse sequence is required.
This differs from the procedure described in the section 3.4.1 "The
procedure when powering down the PE" of ARM IHI0064H.b, which involves
the OS Lock to prevent external debugger accesses and implicitly
disables trace.
To be compatible with different ETM versions, explicitly control trace
unit using etm4_disable_trace_unit() and etm4_enable_trace_unit()
during CPU idle to comply with FEAT_TRF.
As a result, the save states for TRFCR_ELx and trcprgctlr are redundant,
remove them.
Fixes: f188b5e76a ("coresight: etm4x: Save/restore state across CPU low power states")
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251111-arm_coresight_power_management_fix-v6-6-f55553b6c8b3@arm.com
According to the software usage PKLXF in Arm ARM (ARM DDI 0487 L.a), a
Context synchronization event is required before enabling the trace
unit.
An ISB is added to meet this requirement, particularly for guarding the
operations in the flow:
etm4x_allow_trace()
`> kvm_tracing_set_el1_configuration()
`> write_sysreg_s(trfcr_while_in_guest, SYS_TRFCR_EL12)
Improved the barrier comments to provide more accurate information.
Fixes: 1ab3bb9df5 ("coresight: etm4x: Add necessary synchronization for sysreg access")
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Yeoreun Yun <yeoreum.yun@arm.com>
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251111-arm_coresight_power_management_fix-v6-5-f55553b6c8b3@arm.com
When enabling a tracer via SysFS interface, the device mode may be set
by any CPU - not necessarily the target CPU. This can lead to race
condition in SMP, and may result in incorrect mode values being read.
Consider the following example, where CPU0 attempts to enable the tracer
on CPU1 (the target CPU):
CPU0 CPU1
etm4_enable()
` coresight_take_mode(SYSFS)
` etm4_enable_sysfs()
` smp_call_function_single() ----> etm4_enable_hw_smp_call()
/
/ CPU idle:
/ etm4_cpu_save()
/ ` coresight_get_mode()
Failed to enable h/w / ^^^
` coresight_set_mode(DISABLED) <-' Read the intermediate SYSFS mode
In this case, CPU0 initiates the operation by taking the SYSFS mode to
avoid conflicts with the Perf mode. It then sends an IPI to CPU1 to
configure the tracer registers. If any error occurs during this process,
CPU0 rolls back by setting the mode to DISABLED.
However, if CPU1 enters an idle state during this time, it might read
the intermediate SYSFS mode. As a result, the CPU PM flow could wrongly
save and restore tracer context that is actually disabled.
To resolve the issue, this commit moves the device mode setting logic on
the target CPU. This ensures that the device mode is only modified by
the target CPU, eliminating race condition between mode writes and reads
across CPUs.
An additional change introduces the etm4_disable_sysfs_smp_call()
function for SMP calls, which disables the tracer and explicitly set the
mode to DISABLED during SysFS operations. Rename
etm4_disable_hw_smp_call() to etm4_disable_sysfs_smp_call() for naming
consistency.
The flow is updated with this change:
CPU0 CPU1
etm4_enable()
` etm4_enable_sysfs()
` smp_call_function_single() ----> etm4_enable_hw_smp_call()
` coresight_take_mode(SYSFS)
Failed, set back to DISABLED
` coresight_set_mode(DISABLED)
CPU idle:
etm4_cpu_save()
` coresight_get_mode()
^^^
Read out the DISABLED mode
Fixes: c38a9ec2b2 ("coresight: etm4x: moving etm_drvdata::enable to atomic field")
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: mike Leach <mike.leach@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251111-arm_coresight_power_management_fix-v6-2-f55553b6c8b3@arm.com
The handle is essential for retrieving the AUX_EVENT of each CPU and is
required in perf mode. It has been added to the coresight_path so that
dependent devices can access it from the path when needed.
The existing bug can be reproduced with:
perf record -e cs_etm//k -C 0-9 dd if=/dev/zero of=/dev/null
Showing an oops as follows:
Unable to handle kernel paging request at virtual address 000f6e84934ed19e
Call trace:
tmc_etr_get_buffer+0x30/0x80 [coresight_tmc] (P)
catu_enable_hw+0xbc/0x3d0 [coresight_catu]
catu_enable+0x70/0xe0 [coresight_catu]
coresight_enable_path+0xb0/0x258 [coresight]
Fixes: 080ee83cc3 ("Coresight: Change functions to accept the coresight_path")
Signed-off-by: Carl Worth <carl@os.amperecomputing.com>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Co-developed-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250925-fix_helper_data-v2-1-edd8a07c1646@oss.qualcomm.com
James Clark
Linus Torvalds
Ma Ke
Greg Kroah-Hartman
Leo Yan
Jie Gan
Carl Worth