linux-toradex.git/drivers/hwtracing, branch v6.7 Linux kernel for Apalis and Colibri modules coresight: ultrasoc-smb: Fix uninitialized before use buf_hw_base 2023-11-16T10:00:14+00:00 Junhao He hejunhao3@huawei.com 2023-11-14T13:33:45+00:00 862c135bde8bc185e8aae2110374175e6a1b6ed5 In smb_reset_buffer, the sdb->buf_hw_base variable is uninitialized before use, which initializes it in smb_init_data_buffer. And the SMB regiester are set in smb_config_inport. So move the call after smb_config_inport. Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver") Signed-off-by: Junhao He <hejunhao3@huawei.com> Reviewed-by: James Clark <james.clark@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20231114133346.30489-4-hejunhao3@huawei.com 
In smb_reset_buffer, the sdb->buf_hw_base variable is uninitialized
before use, which initializes it in smb_init_data_buffer. And the SMB
regiester are set in smb_config_inport.
So move the call after smb_config_inport.

Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231114133346.30489-4-hejunhao3@huawei.com
coresight: ultrasoc-smb: Config SMB buffer before register sink 2023-11-16T10:00:12+00:00 Junhao He hejunhao3@huawei.com 2023-11-14T13:33:44+00:00 830a7f54db102c889a3fe1c0a225f369ac05f07f The SMB dirver register the enable/disable sysfs interface in function smb_register_sink(), however the buffer depends on the following configuration to work well. So it'll be possible for user to access an unreset one. Move the config buffer operation to before register_sink(). Ignore the return value, if smb_config_inport() fails. That will cause the hardwares disable trace path to fail, should not affect SMB driver remove. So we make smb_remove() return success, Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver") Signed-off-by: Junhao He <hejunhao3@huawei.com> Reviewed-by: James Clark <james.clark@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20231114133346.30489-3-hejunhao3@huawei.com 
The SMB dirver register the enable/disable sysfs interface in function
smb_register_sink(), however the buffer depends on the following
configuration to work well. So it'll be possible for user to access an
unreset one.

Move the config buffer operation to before register_sink().
Ignore the return value, if smb_config_inport() fails. That will
cause the hardwares disable trace path to fail, should not affect
SMB driver remove. So we make smb_remove() return success,

Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231114133346.30489-3-hejunhao3@huawei.com
coresight: ultrasoc-smb: Fix sleep while close preempt in enable_smb 2023-11-16T10:00:09+00:00 Junhao He hejunhao3@huawei.com 2023-11-14T13:33:43+00:00 b8411287aef4a994eff0c68f5597910c4194dfe3 When we to enable the SMB by perf, the perf sched will call perf_ctx_lock() to close system preempt in event_function_call(). But SMB::enable_smb() use mutex to lock the critical section, which may sleep. BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 153023, name: perf preempt_count: 2, expected: 0 RCU nest depth: 0, expected: 0 INFO: lockdep is turned off. irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [<ffffa2983f5c5f40>] copy_process+0xae8/0x2b48 softirqs last enabled at (0): [<ffffa2983f5c5f40>] copy_process+0xae8/0x2b48 softirqs last disabled at (0): [<0000000000000000>] 0x0 CPU: 2 PID: 153023 Comm: perf Kdump: loaded Tainted: G W O 6.5.0-rc4+ #1 Call trace: ... __mutex_lock+0xbc/0xa70 mutex_lock_nested+0x34/0x48 smb_update_buffer+0x58/0x360 [ultrasoc_smb] etm_event_stop+0x204/0x2d8 [coresight] etm_event_del+0x1c/0x30 [coresight] event_sched_out+0x17c/0x3b8 group_sched_out.part.0+0x5c/0x208 __perf_event_disable+0x15c/0x210 event_function+0xe0/0x230 remote_function+0xb4/0xe8 generic_exec_single+0x160/0x268 smp_call_function_single+0x20c/0x2a0 event_function_call+0x20c/0x220 _perf_event_disable+0x5c/0x90 perf_event_for_each_child+0x58/0xc0 _perf_ioctl+0x34c/0x1250 perf_ioctl+0x64/0x98 ... Use spinlock to replace mutex to control driver data access to one at a time. The function copy_to_user() may sleep, it cannot be in a spinlock context, so we can't simply replace it in smb_read(). But we can ensure that only one user gets the SMB device fd by smb_open(), so remove the locks from smb_read() and buffer synchronization is guaranteed by the user. Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver") Signed-off-by: Junhao He <hejunhao3@huawei.com> Reviewed-by: James Clark <james.clark@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20231114133346.30489-2-hejunhao3@huawei.com 
When we to enable the SMB by perf, the perf sched will call perf_ctx_lock()
to close system preempt in event_function_call(). But SMB::enable_smb() use
mutex to lock the critical section, which may sleep.

 BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 153023, name: perf
 preempt_count: 2, expected: 0
 RCU nest depth: 0, expected: 0
 INFO: lockdep is turned off.
 irq event stamp: 0
 hardirqs last  enabled at (0): [<0000000000000000>] 0x0
 hardirqs last disabled at (0): [<ffffa2983f5c5f40>] copy_process+0xae8/0x2b48
 softirqs last  enabled at (0): [<ffffa2983f5c5f40>] copy_process+0xae8/0x2b48
 softirqs last disabled at (0): [<0000000000000000>] 0x0
 CPU: 2 PID: 153023 Comm: perf Kdump: loaded Tainted: G   W  O   6.5.0-rc4+ #1

 Call trace:
 ...
  __mutex_lock+0xbc/0xa70
  mutex_lock_nested+0x34/0x48
  smb_update_buffer+0x58/0x360 [ultrasoc_smb]
  etm_event_stop+0x204/0x2d8 [coresight]
  etm_event_del+0x1c/0x30 [coresight]
  event_sched_out+0x17c/0x3b8
  group_sched_out.part.0+0x5c/0x208
  __perf_event_disable+0x15c/0x210
  event_function+0xe0/0x230
  remote_function+0xb4/0xe8
  generic_exec_single+0x160/0x268
  smp_call_function_single+0x20c/0x2a0
  event_function_call+0x20c/0x220
  _perf_event_disable+0x5c/0x90
  perf_event_for_each_child+0x58/0xc0
  _perf_ioctl+0x34c/0x1250
  perf_ioctl+0x64/0x98
 ...

Use spinlock to replace mutex to control driver data access to one at a
time. The function copy_to_user() may sleep, it cannot be in a spinlock
context, so we can't simply replace it in smb_read(). But we can ensure
that only one user gets the SMB device fd by smb_open(), so remove the
locks from smb_read() and buffer synchronization is guaranteed by the user.

Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231114133346.30489-2-hejunhao3@huawei.com
hwtracing: hisi_ptt: Don't try to attach a task 2023-11-13T09:43:46+00:00 Yicong Yang yangyicong@hisilicon.com 2023-10-10T08:47:30+00:00 aff787f64ad7cbb54614b51b82c682fe06411ef3 PTT is an uncore PMU and shouldn't be attached to any task. Block the usage in pmu::event_init(). Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20231010084731.30450-5-yangyicong@huawei.com 
PTT is an uncore PMU and shouldn't be attached to any task. Block
the usage in pmu::event_init().

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231010084731.30450-5-yangyicong@huawei.com
hwtracing: hisi_ptt: Handle the interrupt in hardirq context 2023-11-13T09:43:33+00:00 Yicong Yang yangyicong@hisilicon.com 2023-10-10T08:47:28+00:00 e0dd27ad8af00f147ac3c9de88e0687986afc3ea Handle the trace interrupt in the hardirq context, make sure the irq core won't threaded it by declaring IRQF_NO_THREAD and userspace won't balance it by declaring IRQF_NOBALANCING. Otherwise we may violate the synchronization requirements of the perf core, referenced to the change of arm-ccn PMU commit 0811ef7e2f54 ("bus: arm-ccn: fix PMU interrupt flags"). In the interrupt handler we mainly doing 2 things: - Copy the data from the local DMA buffer to the AUX buffer - Commit the data in the AUX buffer Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> [ Fixed commit description to suppress checkpatch warning ] Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20231010084731.30450-3-yangyicong@huawei.com 
Handle the trace interrupt in the hardirq context, make sure the irq
core won't threaded it by declaring IRQF_NO_THREAD and userspace won't
balance it by declaring IRQF_NOBALANCING. Otherwise we may violate the
synchronization requirements of the perf core, referenced to the
change of arm-ccn PMU
  commit 0811ef7e2f54 ("bus: arm-ccn: fix PMU interrupt flags").

In the interrupt handler we mainly doing 2 things:
- Copy the data from the local DMA buffer to the AUX buffer
- Commit the data in the AUX buffer

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
[ Fixed commit description to suppress checkpatch warning ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231010084731.30450-3-yangyicong@huawei.com
hwtracing: hisi_ptt: Add dummy callback pmu::read() 2023-11-13T09:43:01+00:00 Junhao He hejunhao3@huawei.com 2023-10-10T08:47:31+00:00 55e0a2fb0cb5ab7c9c99c1ad4d3e6954de8b73a0 When start trace with perf option "-C $cpu" and immediately stop it with SIGTERM or others, the perf core will invoke pmu::read() while the driver doesn't implement it. Add a dummy pmu::read() to avoid any issues. Fixes: ff0de066b463 ("hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device") Signed-off-by: Junhao He <hejunhao3@huawei.com> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20231010084731.30450-6-yangyicong@huawei.com 
When start trace with perf option "-C $cpu" and immediately stop it
with SIGTERM or others, the perf core will invoke pmu::read() while
the driver doesn't implement it. Add a dummy pmu::read() to avoid
any issues.

Fixes: ff0de066b463 ("hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231010084731.30450-6-yangyicong@huawei.com
coresight: Fix crash when Perf and sysfs modes are used concurrently 2023-11-13T09:40:28+00:00 James Clark james.clark@arm.com 2023-10-06T13:14:52+00:00 287e82cf69aa264a52bc37591bd0eb407e20f85c Partially revert the change in commit 6148652807ba ("coresight: Enable and disable helper devices adjacent to the path") which changed the bare call from source_ops(csdev)->enable() to coresight_enable_source() for Perf sessions. It was missed that coresight_enable_source() is specifically for the sysfs interface, rather than being a generic call. This interferes with the sysfs reference counting to cause the following crash: $ perf record -e cs_etm/@tmc_etr0/ -C 0 & $ echo 1 > /sys/bus/coresight/devices/tmc_etr0/enable_sink $ echo 1 > /sys/bus/coresight/devices/etm0/enable_source $ echo 0 > /sys/bus/coresight/devices/etm0/enable_source Unable to handle kernel NULL pointer dereference at virtual address 00000000000001d0 Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP ... Call trace: etm4_disable+0x54/0x150 [coresight_etm4x] coresight_disable_source+0x6c/0x98 [coresight] coresight_disable+0x74/0x1c0 [coresight] enable_source_store+0x88/0xa0 [coresight] dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x120/0x1b8 vfs_write+0x2dc/0x3b0 ksys_write+0x70/0x108 __arm64_sys_write+0x24/0x38 invoke_syscall+0x50/0x128 el0_svc_common.constprop.0+0x104/0x130 do_el0_svc+0x40/0xb8 el0_svc+0x2c/0xb8 el0t_64_sync_handler+0xc0/0xc8 el0t_64_sync+0x1a4/0x1a8 Code: d53cd042 91002000 b9402a81 b8626800 (f940ead5) ---[ end trace 0000000000000000 ]--- This commit linked below also fixes the issue, but has unlocked updates to the mode which could potentially race. So until we come up with a more complete solution that takes all locking and interaction between both modes into account, just revert back to the old behavior for Perf. Reported-by: Junhao He <hejunhao3@huawei.com> Closes: https://lore.kernel.org/linux-arm-kernel/20230921132904.60996-1-hejunhao3@huawei.com/ Fixes: 6148652807ba ("coresight: Enable and disable helper devices adjacent to the path") Tested-by: Junhao He <hejunhao3@huawei.com> Signed-off-by: James Clark <james.clark@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20231006131452.646721-1-james.clark@arm.com 
Partially revert the change in commit 6148652807ba ("coresight: Enable
and disable helper devices adjacent to the path") which changed the bare
call from source_ops(csdev)->enable() to coresight_enable_source() for
Perf sessions. It was missed that coresight_enable_source() is
specifically for the sysfs interface, rather than being a generic call.
This interferes with the sysfs reference counting to cause the following
crash:

  $ perf record -e cs_etm/@tmc_etr0/ -C 0 &
  $ echo 1 > /sys/bus/coresight/devices/tmc_etr0/enable_sink
  $ echo 1 > /sys/bus/coresight/devices/etm0/enable_source
  $ echo 0 > /sys/bus/coresight/devices/etm0/enable_source

  Unable to handle kernel NULL pointer dereference at virtual
  address 00000000000001d0
  Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
  ...
  Call trace:
   etm4_disable+0x54/0x150 [coresight_etm4x]
   coresight_disable_source+0x6c/0x98 [coresight]
   coresight_disable+0x74/0x1c0 [coresight]
   enable_source_store+0x88/0xa0 [coresight]
   dev_attr_store+0x20/0x40
   sysfs_kf_write+0x4c/0x68
   kernfs_fop_write_iter+0x120/0x1b8
   vfs_write+0x2dc/0x3b0
   ksys_write+0x70/0x108
   __arm64_sys_write+0x24/0x38
   invoke_syscall+0x50/0x128
   el0_svc_common.constprop.0+0x104/0x130
   do_el0_svc+0x40/0xb8
   el0_svc+0x2c/0xb8
   el0t_64_sync_handler+0xc0/0xc8
   el0t_64_sync+0x1a4/0x1a8
  Code: d53cd042 91002000 b9402a81 b8626800 (f940ead5)
  ---[ end trace 0000000000000000 ]---

This commit linked below also fixes the issue, but has unlocked updates
to the mode which could potentially race. So until we come up with a
more complete solution that takes all locking and interaction between
both modes into account, just revert back to the old behavior for Perf.

Reported-by: Junhao He <hejunhao3@huawei.com>
Closes: https://lore.kernel.org/linux-arm-kernel/20230921132904.60996-1-hejunhao3@huawei.com/
Fixes: 6148652807ba ("coresight: Enable and disable helper devices adjacent to the path")
Tested-by: Junhao He <hejunhao3@huawei.com>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231006131452.646721-1-james.clark@arm.com
coresight: etm4x: Remove bogous __exit annotation for some functions 2023-11-13T09:40:11+00:00 Uwe Kleine-König u.kleine-koenig@pengutronix.de 2023-09-29T08:16:37+00:00 348ddab81f7b0983d9fb158df910254f08d3f887 etm4_platform_driver (which lives in ".data" contains a reference to etm4_remove_platform_dev(). So the latter must not be marked with __exit which results in the function being discarded for a build with CONFIG_CORESIGHT_SOURCE_ETM4X=y which in turn makes the remove pointer contain invalid data. etm4x_amba_driver referencing etm4_remove_amba() has the same issue. Drop the __exit annotations for the two affected functions and a third one that is called by the other two. For reasons I don't understand this isn't catched by building with CONFIG_DEBUG_SECTION_MISMATCH=y. Fixes: c23bc382ef0e ("coresight: etm4x: Refactor probing routine") Fixes: 5214b563588e ("coresight: etm4x: Add support for sysreg only devices") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: James Clark <james.clark@arm.com> Link: https://lore.kernel.org/all/20230929081540.yija47lsj35xtj4v@pengutronix.de/ Link: https://lore.kernel.org/r/20230929081637.2377335-1-u.kleine-koenig@pengutronix.de Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> 
etm4_platform_driver (which lives in ".data" contains a reference to
etm4_remove_platform_dev(). So the latter must not be marked with __exit
which results in the function being discarded for a build with
CONFIG_CORESIGHT_SOURCE_ETM4X=y which in turn makes the remove pointer
contain invalid data.

etm4x_amba_driver referencing etm4_remove_amba() has the same issue.

Drop the __exit annotations for the two affected functions and a third
one that is called by the other two.

For reasons I don't understand this isn't catched by building with
CONFIG_DEBUG_SECTION_MISMATCH=y.

Fixes: c23bc382ef0e ("coresight: etm4x: Refactor probing routine")
Fixes: 5214b563588e ("coresight: etm4x: Add support for sysreg only devices")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/all/20230929081540.yija47lsj35xtj4v@pengutronix.de/
Link: https://lore.kernel.org/r/20230929081637.2377335-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
coresight: tmc-etr: Disable warnings for allocation failures 2023-09-20T09:46:30+00:00 Suzuki K Poulose suzuki.poulose@arm.com 2023-08-17T16:19:51+00:00 e5028011885a85032aa3c1b7e3e493bcdacb4a0a Running the following command on Juno triggers the warning: $ perf record -e cs_etm// -m ,128M ... ------------[ cut here ]------------ WARNING: CPU: 1 PID: 412 at mm/page_alloc.c:4453 __alloc_pages+0x334/0x1420 CPU: 1 PID: 412 Comm: perf Not tainted 6.5.0-rc3+ #181 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb 1 2019 pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __alloc_pages+0x334/0x1420 lr : dma_common_alloc_pages+0x108/0x138 sp : ffffffc087fb7440 x29: ffffffc087fb7440 x28: 0000000000000000 x27: ffffffc07e48fba0 x26: 0000000000000001 x25: 000000000000000f x24: ffffffc081f24880 x23: 0000000000000cc0 x22: ffffff88012b6f08 x21: 0000000008000000 x20: ffffff8801433000 x19: 0000000000000000 x18: 0000000000000000 x17: ffffffc080316e5c x16: ffffffc07e46406c x15: ffffffc0803af580 x14: ffffffc08036b460 x13: ffffffc080025cbc x12: ffffffb8108c3fc4 x11: 1ffffff8108c3fc3 x10: 1ffffff810ff6eac x9 : 00000000f204f204 x8 : 000000000000f204 x7 : 00000000f2f2f2f2 x6 : 00000000f3f3f3f3 x5 : 0000000000000001 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000cc0 x1 : 0000000000000000 x0 : ffffffc085333000 Call trace: __alloc_pages+0x334/0x1420 dma_common_alloc_pages+0x108/0x138 __dma_alloc_pages+0xf4/0x108 dma_alloc_pages+0x18/0x30 tmc_etr_alloc_flat_buf+0xa0/0x190 [coresight_tmc] tmc_alloc_etr_buf.constprop.0+0x124/0x298 [coresight_tmc] alloc_etr_buf.constprop.0.isra.0+0x88/0xc8 [coresight_tmc] tmc_alloc_etr_buffer+0x164/0x2f0 [coresight_tmc] etm_setup_aux+0x32c/0x520 [coresight] rb_alloc_aux+0x29c/0x3f8 perf_mmap+0x59c/0xce0 mmap_region+0x340/0x10e0 do_mmap+0x48c/0x580 vm_mmap_pgoff+0x160/0x248 ksys_mmap_pgoff+0x1e8/0x278 __arm64_sys_mmap+0x8c/0xb8 With the flat mode, we only attempt to allocate large memory if there is an IOMMU connected to the ETR. If the allocation fails, we always have a fallback path and return an error if nothing else worked. So, suppress the warning for flat mode allocations. Cc: Mike Leach <mike.leach@linaro.org> Cc: James Clark <james.clark@arm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: James Clark <james.clark@arm.com> Link: https://lore.kernel.org/r/20230817161951.658534-1-suzuki.poulose@arm.com 
Running the following command on Juno triggers the warning:

 $ perf record -e cs_etm// -m ,128M ...

 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 412 at mm/page_alloc.c:4453 __alloc_pages+0x334/0x1420
 CPU: 1 PID: 412 Comm: perf Not tainted 6.5.0-rc3+ #181
 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb  1 2019
 pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : __alloc_pages+0x334/0x1420
 lr : dma_common_alloc_pages+0x108/0x138
 sp : ffffffc087fb7440
 x29: ffffffc087fb7440 x28: 0000000000000000 x27: ffffffc07e48fba0
 x26: 0000000000000001 x25: 000000000000000f x24: ffffffc081f24880
 x23: 0000000000000cc0 x22: ffffff88012b6f08 x21: 0000000008000000
 x20: ffffff8801433000 x19: 0000000000000000 x18: 0000000000000000
 x17: ffffffc080316e5c x16: ffffffc07e46406c x15: ffffffc0803af580
 x14: ffffffc08036b460 x13: ffffffc080025cbc x12: ffffffb8108c3fc4
 x11: 1ffffff8108c3fc3 x10: 1ffffff810ff6eac x9 : 00000000f204f204
 x8 : 000000000000f204 x7 : 00000000f2f2f2f2 x6 : 00000000f3f3f3f3
 x5 : 0000000000000001 x4 : 0000000000000000 x3 : 0000000000000000
 x2 : 0000000000000cc0 x1 : 0000000000000000 x0 : ffffffc085333000
 Call trace:
  __alloc_pages+0x334/0x1420
  dma_common_alloc_pages+0x108/0x138
  __dma_alloc_pages+0xf4/0x108
  dma_alloc_pages+0x18/0x30
  tmc_etr_alloc_flat_buf+0xa0/0x190 [coresight_tmc]
  tmc_alloc_etr_buf.constprop.0+0x124/0x298 [coresight_tmc]
  alloc_etr_buf.constprop.0.isra.0+0x88/0xc8 [coresight_tmc]
  tmc_alloc_etr_buffer+0x164/0x2f0 [coresight_tmc]
  etm_setup_aux+0x32c/0x520 [coresight]
  rb_alloc_aux+0x29c/0x3f8
  perf_mmap+0x59c/0xce0
  mmap_region+0x340/0x10e0
  do_mmap+0x48c/0x580
  vm_mmap_pgoff+0x160/0x248
  ksys_mmap_pgoff+0x1e8/0x278
  __arm64_sys_mmap+0x8c/0xb8

With the flat mode, we only attempt to allocate large memory if there is an IOMMU
connected to the ETR. If the allocation fails, we always have a fallback path
and return an error if nothing else worked. So, suppress the warning for flat
mode allocations.

Cc: Mike Leach <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20230817161951.658534-1-suzuki.poulose@arm.com
coresight: Fix run time warnings while reusing ETR buffer 2023-09-15T15:09:18+00:00 Linu Cherian lcherian@marvell.com 2023-08-23T04:29:48+00:00 bd2767ec3df2775bc336f441f9068a989ccb919d Fix the below warning by avoding calls to tmc_etr_enable_hw, if we are reusing the ETR buffer for multiple sources in sysfs mode. echo 1 > /sys/bus/coresight/devices/tmc_etr0/enable_sink echo 1 > /sys/bus/coresight/devices/ete1/enable_source echo 1 > /sys/bus/coresight/devices/ete2/enable_source [ 166.918290] ------------[ cut here ]------------ [ 166.922905] WARNING: CPU: 4 PID: 2288 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1037 tmc_etr_enable_hw+0xb0/0xc8 [ 166.933862] Modules linked in: [ 166.936911] CPU: 4 PID: 2288 Comm: bash Not tainted 6.5.0-rc7 #132 [ 166.943084] Hardware name: Marvell CN106XX board (DT) [ 166.948127] pstate: 834000c9 (Nzcv daIF +PAN -UAO +TCO +DIT -SSBS BTYPE=--) [ 166.955083] pc : tmc_etr_enable_hw+0xb0/0xc8 [ 166.959345] lr : tmc_enable_etr_sink+0x134/0x210 snip.. 167.038545] Call trace: [ 167.040982] tmc_etr_enable_hw+0xb0/0xc8 [ 167.044897] tmc_enable_etr_sink+0x134/0x210 [ 167.049160] coresight_enable_path+0x160/0x278 [ 167.053596] coresight_enable+0xd4/0x298 [ 167.057510] enable_source_store+0x54/0xa0 [ 167.061598] dev_attr_store+0x20/0x40 [ 167.065254] sysfs_kf_write+0x4c/0x68 [ 167.068909] kernfs_fop_write_iter+0x128/0x200 [ 167.073345] vfs_write+0x1ac/0x2f8 [ 167.076739] ksys_write+0x74/0x110 [ 167.080132] __arm64_sys_write+0x24/0x38 [ 167.084045] invoke_syscall.constprop.0+0x58/0xf8 [ 167.088744] do_el0_svc+0x60/0x160 [ 167.092137] el0_svc+0x40/0x170 [ 167.095273] el0t_64_sync_handler+0x100/0x130 [ 167.099621] el0t_64_sync+0x190/0x198 [ 167.103277] ---[ end trace 0000000000000000 ]--- -bash: echo: write error: Device or resource busy Fixes: 296b01fd106e ("coresight: Refactor out buffer allocation function for ETR") Signed-off-by: Linu Cherian <lcherian@marvell.com> Reviewed-by: James Clark <james.clark@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20230823042948.12879-1-lcherian@marvell.com 
Fix the below warning by avoding calls to tmc_etr_enable_hw,
if we are reusing the ETR buffer for multiple sources in sysfs mode.

echo 1 > /sys/bus/coresight/devices/tmc_etr0/enable_sink
echo 1 > /sys/bus/coresight/devices/ete1/enable_source
echo 1 > /sys/bus/coresight/devices/ete2/enable_source
[  166.918290] ------------[ cut here ]------------
[  166.922905] WARNING: CPU: 4 PID: 2288 at
drivers/hwtracing/coresight/coresight-tmc-etr.c:1037
tmc_etr_enable_hw+0xb0/0xc8
[  166.933862] Modules linked in:
[  166.936911] CPU: 4 PID: 2288 Comm: bash Not tainted 6.5.0-rc7 #132
[  166.943084] Hardware name: Marvell CN106XX board (DT)
[  166.948127] pstate: 834000c9 (Nzcv daIF +PAN -UAO +TCO +DIT -SSBS
BTYPE=--)
[  166.955083] pc : tmc_etr_enable_hw+0xb0/0xc8
[  166.959345] lr : tmc_enable_etr_sink+0x134/0x210
snip..
  167.038545] Call trace:
[  167.040982]  tmc_etr_enable_hw+0xb0/0xc8
[  167.044897]  tmc_enable_etr_sink+0x134/0x210
[  167.049160]  coresight_enable_path+0x160/0x278
[  167.053596]  coresight_enable+0xd4/0x298
[  167.057510]  enable_source_store+0x54/0xa0
[  167.061598]  dev_attr_store+0x20/0x40
[  167.065254]  sysfs_kf_write+0x4c/0x68
[  167.068909]  kernfs_fop_write_iter+0x128/0x200
[  167.073345]  vfs_write+0x1ac/0x2f8
[  167.076739]  ksys_write+0x74/0x110
[  167.080132]  __arm64_sys_write+0x24/0x38
[  167.084045]  invoke_syscall.constprop.0+0x58/0xf8
[  167.088744]  do_el0_svc+0x60/0x160
[  167.092137]  el0_svc+0x40/0x170
[  167.095273]  el0t_64_sync_handler+0x100/0x130
[  167.099621]  el0t_64_sync+0x190/0x198
[  167.103277] ---[ end trace 0000000000000000 ]---
-bash: echo: write error: Device or resource busy

Fixes: 296b01fd106e ("coresight: Refactor out buffer allocation function for ETR")
Signed-off-by: Linu Cherian <lcherian@marvell.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230823042948.12879-1-lcherian@marvell.com