coresight: trbe: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231116173301.708873-13-u.kleine-koenig@pengutronix.de

coresight: trbe: Enable ACPI based TRBE devices

This detects and enables ACPI based TRBE devices via the dummy platform
device created earlier for this purpose.

Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230829135405.1159449-3-anshuman.khandual@arm.com

coresight: trbe: Add a representative coresight_platform_data for TRBE

TRBE coresight devices do not need regular connections information, as the
paths get built between all percpu source and their respective percpu sink
devices. Please refer 'commit 2cd87a7b293d ("coresight: core: Add support
for dedicated percpu sinks")' which added support for percpu sink devices.

coresight_register() expect device connections via the platform_data. TRBE
devices do not have any graph connections and thus is empty. With upcoming
ACPI support for TRBE, we do not get a real acpi_device and thus
coresight_get_platform_dat() will end up in failures. Hence this allocates
a zeroed coresight_platform_data structure and assigns that back into the
device.

Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230829135405.1159449-2-anshuman.khandual@arm.com

coresight: trbe: Fix TRBE potential sleep in atomic context

smp_call_function_single() will allocate an IPI interrupt vector to
the target processor and send a function call request to the interrupt
vector. After the target processor receives the IPI interrupt, it will
execute arm_trbe_remove_coresight_cpu() call request in the interrupt
handler.

According to the device_unregister() stack information, if other process
is useing the device, the down_write() may sleep, and trigger deadlocks
or unexpected errors.

arm_trbe_remove_coresight_cpu
coresight_unregister
device_unregister
device_del
kobject_del
__kobject_del
sysfs_remove_dir
kernfs_remove
down_write ---------> it may sleep

Add a helper arm_trbe_disable_cpu() to disable TRBE precpu irq and reset
per TRBE.
Simply call arm_trbe_remove_coresight_cpu() directly without useing the
smp_call_function_single(), which is the same as registering the TRBE
coresight device.

Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Link: https://lore.kernel.org/r/20230814093813.19152-2-hejunhao3@huawei.com
[ Remove duplicate cpumask checks during removal ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
[ v3 - Remove the operation of assigning NULL to cpudata->drvdata ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230818084052.10116-1-hejunhao3@huawei.com

coresight: trbe: Allocate platform data per device

Coresight TRBE driver shares a single platform data (which is empty btw).
However, with the commit 4e8fe7e5c3a5
("coresight: Store pointers to connections rather than an array of them")
the coresight core would free up the pdata, resulting in multiple attempts
to free the same pdata for TRBE instances. Fix this by allocating a pdata per
coresight_device.

Fixes: 4e8fe7e5c3a5 ("coresight: Store pointers to connections rather than an array of them")
Link: https://lore.kernel.org/r/20230814093813.19152-3-hejunhao3@huawei.com
Reported-by: Junhao He <hejunhao3@huawei.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: James Clark <james.clark@arm.com>
Tested-by: Junhao He <hejunhao3@huawei.com>
Link: https://lore.kernel.org/r/20230816141008.535450-2-suzuki.poulose@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: Use enum type for cs_mode wherever possible

mode is stored as a local_t, but it is also passed around a lot as a
plain u32, so use the correct type wherever local_t isn't currently
used. This helps a little bit with readability.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
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/20230425143542.2305069-3-james.clark@arm.com

arm64/sysreg: Rename TRBSR_EL1 fields per auto-gen tools format

This renames TRBSR_EL1 register fields per auto-gen tools format without
causing any functional change in the TRBE driver.

Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: kvmarm@lists.linux.dev
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230614065949.146187-5-anshuman.khandual@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64/sysreg: Rename TRBLIMITR_EL1 fields per auto-gen tools format

This renames TRBLIMITR_EL1 register fields per auto-gen tools format
without causing any functional change in the TRBE driver.

Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: kvmarm@lists.linux.dev
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230614065949.146187-2-anshuman.khandual@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

coresight: trbe: remove cpuhp instance node before remove cpuhp state

cpuhp_state_add_instance() and cpuhp_state_remove_instance() should
be used in pairs. Or there will lead to the warn on
cpuhp_remove_multi_state() since the cpuhp_step list is not empty.

The following is the error log with 'rmmod coresight-trbe':
Error: Removing state 215 which has instances left.
Call trace:
__cpuhp_remove_state_cpuslocked+0x144/0x160
__cpuhp_remove_state+0xac/0x100
arm_trbe_device_remove+0x2c/0x60 [coresight_trbe]
platform_remove+0x34/0x70
device_remove+0x54/0x90
device_release_driver_internal+0x1e4/0x250
driver_detach+0x5c/0xb0
bus_remove_driver+0x64/0xc0
driver_unregister+0x3c/0x70
platform_driver_unregister+0x20/0x30
arm_trbe_exit+0x1c/0x658 [coresight_trbe]
__arm64_sys_delete_module+0x1ac/0x24c
invoke_syscall+0x50/0x120
el0_svc_common.constprop.0+0x58/0x1a0
do_el0_svc+0x38/0xd0
el0_svc+0x2c/0xc0
el0t_64_sync_handler+0x1ac/0x1b0
el0t_64_sync+0x19c/0x1a0
---[ end trace 0000000000000000 ]---

Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Yang Shen <shenyang39@huawei.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20221122090355.23533-1-shenyang39@huawei.com

coresight: trbe: Move check for kernel page table isolation from EL0 to probe

Currently with the check present in the module initialisation, it shouts
on all the systems irrespective of presence of coresight trace buffer
extensions.

Similar to Arm SPE perf driver, move the check for kernel page table
isolation from EL0 to the device probe stage instead of the module
initialisation so that it complains only on the systems that support TRBE.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: coresight@lists.linaro.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20220203190159.3145272-1-sudeep.holla@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: trbe: Work around the trace data corruption

TRBE implementations affected by Arm erratum #1902691 might corrupt trace
data or deadlock, when it's being written into the memory. Workaround this
problem in the driver, by preventing TRBE initialization on affected cpus.
The firmware must have disabled the access to TRBE for the kernel on such
implementations. This will cover the kernel for any firmware that doesn't
do this already. This just updates the TRBE driver as required.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-doc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/1643120437-14352-8-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: trbe: Work around the invalid prohibited states

TRBE implementations affected by Arm erratum #2038923 might get TRBE into
an inconsistent view on whether trace is prohibited within the CPU. As a
result, the trace buffer or trace buffer state might be corrupted. This
happens after TRBE buffer has been enabled by setting TRBLIMITR_EL1.E,
followed by just a single context synchronization event before execution
changes from a context, in which trace is prohibited to one where it isn't,
or vice versa. In these mentioned conditions, the view of whether trace is
prohibited is inconsistent between parts of the CPU, and the trace buffer
or the trace buffer state might be corrupted.

Work around this problem in the TRBE driver by preventing an inconsistent
view of whether the trace is prohibited or not based on TRBLIMITR_EL1.E by
immediately following a change to TRBLIMITR_EL1.E with at least one ISB
instruction before an ERET, or two ISB instructions if no ERET is to take
place. This just updates the TRBE driver as required.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-doc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/1643120437-14352-7-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: trbe: Work around the ignored system register writes

TRBE implementations affected by Arm erratum #2064142 might fail to write
into certain system registers after the TRBE has been disabled. Under some
conditions after TRBE has been disabled, writes into certain TRBE registers
TRBLIMITR_EL1, TRBPTR_EL1, TRBBASER_EL1, TRBSR_EL1 and TRBTRG_EL1 will be
ignored and not be effected.

Work around this problem in the TRBE driver by executing TSB CSYNC and DSB
just after the trace collection has stopped and before performing a system
register write to one of the affected registers. This just updates the TRBE
driver as required.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-doc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/1643120437-14352-6-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: trbe: Work around write to out of range

TRBE implementations affected by Arm erratum (2253138 or 2224489), could
write to the next address after the TRBLIMITR.LIMIT, instead of wrapping
to the TRBBASER. This implies that the TRBE could potentially corrupt :

- A page used by the rest of the kernel/user (if the LIMIT = end of
perf ring buffer)
- A page within the ring buffer, but outside the driver's range.
[head, head + size]. This may contain some trace data, may be
consumed by the userspace.

We workaround this erratum by :
- Making sure that there is at least an extra PAGE space left in the
TRBE's range than we normally assign. This will be additional to other
restrictions (e.g, the TRBE alignment for working around
TRBE_WORKAROUND_OVERWRITE_IN_FILL_MODE, where there is a minimum of
PAGE_SIZE. Thus we would have 2 * PAGE_SIZE)

- Adjust the LIMIT to leave the last PAGE_SIZE out of the TRBE's allowed
range (i.e, TRBEBASER...TRBLIMITR.LIMIT), by :

TRBLIMITR.LIMIT -= PAGE_SIZE

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-14-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Make sure we have enough space

The TRBE driver makes sure that there is enough space for a meaningful
run, otherwise pads the given space and restarts the offset calculation
once. But there is no guarantee that we may find space or hit "no space".
Make sure that we repeat the step until, either :
- We have the minimum space
OR
- There is NO space at all.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-13-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Add a helper to determine the minimum buffer size

For the TRBE to operate, we need a minimum space available to collect
meaningful trace session. This is currently a few bytes, but we may need
to extend this for working around errata. So, abstract this into a helper
function.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-12-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Workaround TRBE errata overwrite in FILL mode

ARM Neoverse-N2 (#2139208) and Cortex-A710(##2119858) suffers from
an erratum, which when triggered, might cause the TRBE to overwrite
the trace data already collected in FILL mode, in the event of a WRAP.
i.e, the TRBE doesn't stop writing the data, instead wraps to the base
and could write upto 3 cache line size worth trace. Thus, this could
corrupt the trace at the "BASE" pointer.

The workaround is to program the write pointer 256bytes from the
base, such that if the erratum is triggered, it doesn't overwrite
the trace data that was captured. This skipped region could be
padded with ignore packets at the end of the session, so that
the decoder sees a continuous buffer with some padding at the
beginning. The trace data written at the base is considered
lost as the limit could have been in the middle of the perf
ring buffer, and jumping to the "base" is not acceptable.
We set the flags already to indicate that some amount of trace
was lost during the FILL event IRQ. So this is fine.

One important change with the work around is, we program the
TRBBASER_EL1 to current page where we are allowed to write.
Otherwise, it could overwrite a region that may be consumed
by the perf. Towards this, we always make sure that the
"handle->head" and thus the trbe_write is PAGE_SIZE aligned,
so that we can set the BASE to the PAGE base and move the
TRBPTR to the 256bytes offset.

Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-11-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Add infrastructure for Errata handling

Add a minimal infrastructure to keep track of the errata
affecting the given TRBE instance. Given that we have
heterogeneous CPUs, we have to manage the list per-TRBE
instance to be able to apply the work around as needed.
Thus we will need to check if individual CPUs are affected
by the erratum.

We rely on the arm64 errata framework for the actual
description and the discovery of a given erratum, to
keep the Erratum work around at a central place and
benefit from the code and the advertisement from the
kernel. Though we could reuse the "this_cpu_has_cap()"
to apply an erratum work around, it is a bit of a heavy
operation, as it must go through the "erratum" detection
check on the CPU every time it is called (e.g, scanning
through a table of affected MIDRs). Since we need
to do this check for every session, may be multiple
times (depending on the wrok around), we could save
the cycles by caching the affected errata per-CPU
instance in the per-CPU struct trbe_cpudata.

Since we are only interested in the errata affecting
the TRBE driver, we only need to track a very few of them
per-CPU. Thus we use a local mapping of the CPUCAP for the
erratum to avoid bloating up a bitmap for trbe_cpudata.

i.e, each arm64 TRBE erratum bit is assigned a "index"
within the driver to track. Each trbe instance updates
the list of affected erratum at probe time on the CPU.
This makes sure that we can easily access the list of
errata on a given TRBE instance without much overhead.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-10-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Allow driver to choose a different alignment

The TRBE hardware mandates a minimum alignment for the TRBPTR_EL1,
advertised via the TRBIDR_EL1. This is used by the driver to
align the buffer write head. This patch allows the driver to
choose a different alignment from that of the hardware, by
decoupling the alignment tracking. This will be useful for
working around errata.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-9-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Decouple buffer base from the hardware base

We always set the TRBBASER_EL1 to the base of the virtual ring
buffer. We are about to change this for working around an erratum.
So, in preparation to that, allow the driver to choose a different
base for the TRBBASER_EL1 (which is within the buffer range).

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-8-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Add a helper to pad a given buffer area

Refactor the helper to pad a given AUX buffer area to allow
"filling" ignore packets, without moving any handle pointers.
This will be useful in working around errata, where we may
have to fill the buffer after a session.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-7-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Add a helper to calculate the trace generated

We collect the trace from the TRBE on FILL event from IRQ context
and via update_buffer(), when the event is stopped. Let us
consolidate how we calculate the trace generated into a helper.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20211019163153.3692640-6-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Defer the probe on offline CPUs

If a CPU is offline during the driver init, we could end up causing
a kernel crash trying to register the coresight device for the TRBE
instance. The trbe_cpudata for the TRBE instance is initialized only
when it is probed. Otherwise, we could end up dereferencing a NULL
cpudata->drvdata.

e.g:

[ 0.149999] coresight ete0: CPU0: ete v1.1 initialized
[ 0.149999] coresight-etm4x ete_1: ETM arch init failed
[ 0.149999] coresight-etm4x: probe of ete_1 failed with error -22
[ 0.150085] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000050
[ 0.150085] Mem abort info:
[ 0.150085] ESR = 0x96000005
[ 0.150085] EC = 0x25: DABT (current EL), IL = 32 bits
[ 0.150085] SET = 0, FnV = 0
[ 0.150085] EA = 0, S1PTW = 0
[ 0.150085] Data abort info:
[ 0.150085] ISV = 0, ISS = 0x00000005
[ 0.150085] CM = 0, WnR = 0
[ 0.150085] [0000000000000050] user address but active_mm is swapper
[ 0.150085] Internal error: Oops: 96000005 [#1] PREEMPT SMP
[ 0.150085] Modules linked in:
[ 0.150085] Hardware name: FVP Base RevC (DT)
[ 0.150085] pstate: 00800009 (nzcv daif -PAN +UAO -TCO BTYPE=--)
[ 0.150155] pc : arm_trbe_register_coresight_cpu+0x74/0x144
[ 0.150155] lr : arm_trbe_register_coresight_cpu+0x48/0x144
...

[ 0.150237] Call trace:
[ 0.150237] arm_trbe_register_coresight_cpu+0x74/0x144
[ 0.150237] arm_trbe_device_probe+0x1c0/0x2d8
[ 0.150259] platform_drv_probe+0x94/0xbc
[ 0.150259] really_probe+0x1bc/0x4a8
[ 0.150266] driver_probe_device+0x7c/0xb8
[ 0.150266] device_driver_attach+0x6c/0xac
[ 0.150266] __driver_attach+0xc4/0x148
[ 0.150266] bus_for_each_dev+0x7c/0xc8
[ 0.150266] driver_attach+0x24/0x30
[ 0.150266] bus_add_driver+0x100/0x1e0
[ 0.150266] driver_register+0x78/0x110
[ 0.150266] __platform_driver_register+0x44/0x50
[ 0.150266] arm_trbe_init+0x28/0x84
[ 0.150266] do_one_initcall+0x94/0x2bc
[ 0.150266] do_initcall_level+0xa4/0x158
[ 0.150266] do_initcalls+0x54/0x94
[ 0.150319] do_basic_setup+0x24/0x30
[ 0.150319] kernel_init_freeable+0xe8/0x14c
[ 0.150319] kernel_init+0x14/0x18c
[ 0.150319] ret_from_fork+0x10/0x30
[ 0.150319] Code: f94012c8 b0004ce2 9134a442 52819801 (f9402917)
[ 0.150319] ---[ end trace d23e0cfe5098535e ]---
[ 0.150346] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Fix this by skipping the step, if we are unable to probe the CPU.

Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
Reported-by: Bransilav Rankov <branislav.rankov@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: stable <stable@vger.kernel.org>
Tested-by: Branislav Rankov <branislav.rankov@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20211014142238.2221248-1-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Fix incorrect access of the sink specific data

The TRBE driver wrongly treats the aux private data as the TRBE driver
specific buffer for a given perf handle, while it is the ETM PMU's
event specific data. Fix this by correcting the instance to use
appropriate helper.

Cc: stable <stable@vger.kernel.org>
Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20210921134121.2423546-2-suzuki.poulose@arm.com
[Fixed 13 character SHA down to 12]
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Prohibit trace before disabling TRBE

When the TRBE generates an IRQ, we stop the TRBE, collect the trace
and then reprogram the TRBE with the updated buffer pointers, whenever
possible. We might also leave the TRBE disabled, if there is not
enough space left in the buffer. However, we do not touch the ETE at
all during all of this. This means the ETE is only disabled when
the event is disabled later (via irq_work). This is incorrect, as the
ETE trace is still ON without actually being captured and may be routed
to the ATB (even if it is for a short duration).

So, we move the CPU into trace prohibited state always before disabling
the TRBE, upon entering the IRQ handler. The state is restored if the
TRBE is enabled back. Otherwise the trace remains prohibited.

Since, the ETM/ETE driver now controls the TRFCR_EL1 per session, the
tracing can be restored/enabled back when the event is rescheduled
in.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210923143919.2944311-6-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: End the AUX handle on truncation

When we detect that there isn't enough space left to start a meaningful
session, we disable the TRBE, marking the buffer as TRUNCATED. But we delay
the notification to the perf layer by perf_aux_output_end() until the event
is scheduled out, triggered from the kernel perf layer. This will cause
significant black outs in the trace. Now that the CoreSight PMU layer can
handle a closed "AUX" handle properly, we can close the handle as soon as
we detect the case, allowing the userspace to collect and re-enable the
event.

Also, while in the IRQ handler, move the irq_work_run() after we have
updated the handle, to make sure the "TRUNCATED" flag causes the event to
be disabled as soon as possible.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210923143919.2944311-5-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Do not truncate buffer on IRQ

The TRBE driver marks the AUX buffer as TRUNCATED when we get an IRQ
on FILL event. This has rather unwanted side-effect of the event
being disabled when there may be more space in the ring buffer.

So, instead of TRUNCATE we need a different flag to indicate
that the trace may have lost a few bytes (i.e from the point of
generating the FILL event until the IRQ is consumed). Anyways, the
userspace must use the size from RECORD_AUX headers to restrict
the "trace" decoding.

Using PARTIAL flag causes the perf tool to generate the
following warning:

Warning:
AUX data had gaps in it XX times out of YY!

Are you running a KVM guest in the background?

which is pointlessly scary for a user. The other remaining options
are :
- COLLISION - Use by SPE to indicate samples collided
- Add a new flag - Specifically for CoreSight, doesn't sound
so good, if we can re-use something.

Given that we don't already use the "COLLISION" flag, the above
behavior can be notified using this flag for CoreSight.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210923143919.2944311-4-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Fix handling of spurious interrupts

On a spurious IRQ, right now we disable the TRBE and then re-enable
it back, resetting the "buffer" pointers(i.e BASE, LIMIT and more
importantly WRITE) to the original pointers from the AUX handle.
This implies that we overwrite any trace that was written so far,
(by overwriting TRBPTR) while we should have ignored the IRQ.

On detecting a spurious IRQ after examining the TRBSR we simply
re-enable the TRBE without touching the other parameters.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210923143919.2944311-3-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: irq handler: Do not disable TRBE if no action is needed

The IRQ handler of the TRBE driver could race against the update_buffer()
in consuming the IRQ. So, if the update_buffer() gets to processing the
TRBE irq, the TRBSR will be cleared. Thus by the time IRQ handler is
triggered, there is nothing to do there. Handle these cases and do not
disable the TRBE unnecessarily. Since the TRBSR can be read without
stopping the TRBE, we can check that before disabling the TRBE.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210923143919.2944311-2-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Unify the enabling sequence

Unify the sequence of enabling the TRBE. We do this from
event_start and also from the TRBE IRQ handler. Lets move
this to a common helper. The only minor functional change
is returning an error when we fail to enable the TRBE.
This should be handled already.

Since we now have unique entry point to trying to enable TRBE,
move the format flag setting to the central place.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210914102641.1852544-9-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Drop duplicate TRUNCATE flags

We mark the buffer as TRUNCATED when there is no space left
in the buffer. But we do it at different points.
__trbe_normal_offset()
and also, at all the callers of the above function via
compute_trbe_buffer_limit(), when the limit == base (i.e
offset = 0 as returned by the __trbe_normal_offset()).

So, given that the callers already mark the buffer as TRUNCATED
drop the caller inside the __trbe_normal_offset().

This is in preparation to moving the handling of TRUNCATED
into a central place.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20210914102641.1852544-6-suzuki.poulose@arm.com
[Moved comment as Anshuman requested]
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Ensure the format flag is always set

When the TRBE is stopped on truncating an event, we may not
set the FORMAT flag, even though the size of the record is 0.
Let us be consistent and not confuse the user.

To ensure that the format flag is always set on all the
records generated by TRBE, set the flag when we have a
new handle. Rather than deferring to the "end" operation,
which makes it clear. So, we can do this from

- arm_trbe_enable() -> When a new handle is provided by the
CoreSight PMU, triggered via etm_event_start()
- trbe_handle_overflow() -> When we begin a new handle after
closing the previous on overflow.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20210914102641.1852544-5-suzuki.poulose@arm.com
[Fixed inverted words in title]
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: trbe: Fix return value check in arm_trbe_register_coresight_cpu()

In case of error, the function devm_kasprintf() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value
check should be replaced with NULL test.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20210409094901.1903622-1-weiyongjun1@huawei.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

coresight: sink: Add TRBE driver

Trace Buffer Extension (TRBE) implements a trace buffer per CPU which is
accessible via the system registers. The TRBE supports different addressing
modes including CPU virtual address and buffer modes including the circular
buffer mode. The TRBE buffer is addressed by a base pointer (TRBBASER_EL1),
an write pointer (TRBPTR_EL1) and a limit pointer (TRBLIMITR_EL1). But the
access to the trace buffer could be prohibited by a higher exception level
(EL3 or EL2), indicated by TRBIDR_EL1.P. The TRBE can also generate a CPU
private interrupt (PPI) on address translation errors and when the buffer
is full. Overall implementation here is inspired from the Arm SPE driver.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
[ Mark the buffer truncated on WRAP event, error code cleanup ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210405164307.1720226-18-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>