perf: arm-cci: 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.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/70b581d58cfffdccb9fb3ed17bf3220c00f8033f.1702648124.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Will Deacon <will@kernel.org>

drivers/perf: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230714174832.4061752-1-robh@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

perf/arm-cci: Slightly optimize cci_pmu_sync_counters()

When the 'mask' bitmap is cleared, it is better to use its full maximum
size instead of only the needed size.
This lets the compiler optimize it because the size is now known at compile
time. HW_CNTRS_MAX is small (i.e. currently 9), so a call to memset() is
saved.

Also, as 'mask' is local to the function, the non-atomic __set_bit() can
also safely be used here.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/88d4e20d595f771396e9d558c1587eb4494057db.1682022422.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Will Deacon <will@kernel.org>

perf/arm-cci: Use the bitmap API to allocate bitmaps

Use devm_bitmap_zalloc() instead of hand-writing it.
It is less verbose and it improves the semantic.

While at it, use bitmap_zero() instead of hand-writing it.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/fbde85a5e8ae99b10a2115d8ea1e69320a62947f.1657084786.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Will Deacon <will@kernel.org>

perf/arm-cci: fix typo in comment

Spelling mistake (triple letters) in comment.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Link: https://lore.kernel.org/r/20220521111145.81697-67-Julia.Lawall@inria.fr
Signed-off-by: Will Deacon <will@kernel.org>

perf: replace bitmap_weight with bitmap_empty where appropriate

In some places, drivers/perf code calls bitmap_weight() to check if any
bit of a given bitmap is set. It's better to use bitmap_empty() in that
case because bitmap_empty() stops traversing the bitmap as soon as it
finds first set bit, while bitmap_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220210224933.379149-13-yury.norov@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/perf: arm-cci: Fix checkpatch spacing error

Fix some coding style issues reported by checkpatch.pl, including
following types:

ERROR: need consistent spacing around '-' (ctx:WxV)
ERROR: space required before the open parenthesis '('

Signed-off-by: Junhao He <hejunhao2@hisilicon.com>
Signed-off-by: Jay Fang <f.fangjian@huawei.com>
Link: https://lore.kernel.org/r/1620736054-58412-5-git-send-email-f.fangjian@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/perf: convert sysfs snprintf family to sysfs_emit

Fix the following coccicheck warning:

./drivers/perf/hisilicon/hisi_uncore_pmu.c:128:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/fsl_imx8_ddr_perf.c:173:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm_spe_pmu.c:129:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm_smmu_pmu.c:563:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm_dsu_pmu.c:149:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm_dsu_pmu.c:139:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm-cmn.c:563:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm-cmn.c:351:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm-ccn.c:224:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm-cci.c:708:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm-cci.c:699:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm-cci.c:528:8-16: WARNING: use scnprintf or sprintf.
./drivers/perf/arm-cci.c:309:8-16: WARNING: use scnprintf or sprintf.

Signed-off-by: Zihao Tang <tangzihao1@hisilicon.com>
Signed-off-by: Qi Liu <liuqi115@huawei.com>
Link: https://lore.kernel.org/r/1616148273-16374-2-git-send-email-liuqi115@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/perf: Replace spin_lock_irqsave to spin_lock

There is no need to do spin_lock_irqsave in context of hard IRQ, so
replace them with spin_lock.

Signed-off-by: Qi Liu <liuqi115@huawei.com>
Link: https://lore.kernel.org/r/1612863742-1551-1-git-send-email-liuqi115@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>

perf: Constify static struct attribute_group

The only usage is to put their addresses in an array of pointers to
const struct attribute group. Make them const to allow the compiler
to put them in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20210117212847.21319-5-rikard.falkeborn@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/perf: Prevent forced unbinding of PMU drivers

Forcefully unbinding PMU drivers during perf sampling will lead to
a kernel panic, because the perf upper-layer framework call a NULL
pointer in this situation.

To solve this issue, "suppress_bind_attrs" should be set to true, so
that bind/unbind can be disabled via sysfs and prevent unbinding PMU
drivers during perf sampling.

Signed-off-by: Qi Liu <liuqi115@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1594975763-32966-1-git-send-email-liuqi115@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>

perf/arm-cci: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Will Deacon <will@kernel.org>

perf/arm-cci: Remove broken race mitigation

Uncore PMU drivers face an awkward cyclic dependency wherein:

- They have to pick a valid online CPU to associate with before
registering the PMU device, since it will get exposed to userspace
immediately.
- The PMU registration has to be be at least partly complete before
hotplug events can be handled, since trying to migrate an
uninitialised context would be bad.
- The hotplug handler has to be ready as soon as a CPU is chosen, lest
it go offline without the user-visible cpumask value getting updated.

The arm-cci driver has tried to solve this by using get_cpu() to pick
the current CPU and prevent it from disappearing while both
registrations are performed, but that results in taking mutexes with
preemption disabled, which makes certain configurations very unhappy:

[ 1.983337] BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:2004
[ 1.983340] in_atomic(): 1, irqs_disabled(): 0, pid: 1, name: swapper/0
[ 1.983342] Preemption disabled at:
[ 1.983353] [<ffffff80089801f4>] cci_pmu_probe+0x1dc/0x488
[ 1.983360] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.20-rt8-yocto-preempt-rt #1
[ 1.983362] Hardware name: ZynqMP ZCU102 Rev1.0 (DT)
[ 1.983364] Call trace:
[ 1.983369] dump_backtrace+0x0/0x158
[ 1.983372] show_stack+0x24/0x30
[ 1.983378] dump_stack+0x80/0xa4
[ 1.983383] ___might_sleep+0x138/0x160
[ 1.983386] __might_sleep+0x58/0x90
[ 1.983391] __rt_mutex_lock_state+0x30/0xc0
[ 1.983395] _mutex_lock+0x24/0x30
[ 1.983400] perf_pmu_register+0x2c/0x388
[ 1.983404] cci_pmu_probe+0x2bc/0x488
[ 1.983409] platform_drv_probe+0x58/0xa8

It is not feasible to resolve all the possible races outside of the perf
core itself, so address the immediate bug by following the example of
nearly every other PMU driver and not even trying to do so. Registering
the hotplug notifier first should minimise the window in which things
can go wrong, so that's about as much as we can reasonably do here. This
also revealed an additional race in assigning the global pointer too
late relative to the hotplug notifier, which gets fixed in the process.

Reported-by: Li, Meng <Meng.Li@windriver.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

For drivers that do not support context exclusion let's advertise the
PERF_PMU_CAP_NO_EXCLUDE capability. This ensures that perf will
prevent us from handling events where any exclusion flags are set.
Let's also remove the now unnecessary check for exclusion flags.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: robin.murphy@arm.com
Cc: suzuki.poulose@arm.com
Link: https://lkml.kernel.org/r/1547128414-50693-8-git-send-email-andrew.murray@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

perf/arm-cci: Remove VLA usage

In the quest to remove all stack VLA usage from the kernel[1], this
removes the VLA in favor of a maximum size and adds a sanity check
at registration time. The sizes are all explicitly enumerated already,
so this just collects them into macros.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

drivers/bus: arm-cci: fix build warnings

When the arm-cci driver is enabled, but both CONFIG_ARM_CCI5xx_PMU and
CONFIG_ARM_CCI400_PMU are not, we get a warning about how parts of
the driver are never used:

drivers/perf/arm-cci.c:1454:29: error: 'cci_pmu_models' defined but not used [-Werror=unused-variable]
drivers/perf/arm-cci.c:693:16: error: 'cci_pmu_event_show' defined but not used [-Werror=unused-function]
drivers/perf/arm-cci.c:685:16: error: 'cci_pmu_format_show' defined but not used [-Werror=unused-function]

Marking all three functions as __maybe_unused avoids the warnings in
randconfig builds. I'm doing this lacking any ideas for a better fix.

Fixes: 3de6be7a3dd8 ("drivers/bus: Split Arm CCI driver")
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>

perf/arm-cci: Allow building as a module

Fill in the few extra bits and annotations needed to make the driver
work properly as a module, and jiggle the Kconfig to expose the
driver-level ARM_CCI_PMU option.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

perf/arm-cci: Remove pointless PMU disabling

The CCI PMU driver bears some legacy remnants of the arm_pmu framework
from when it was split in c6f85cb4305b ("bus: cci: move away from
arm_pmu framework"). In particular this perf_pmu_{dis,en}able() dance
around pmu->add which was fixed for arm_pmu in a9e469d1c89b
("drivers/perf: arm_pmu: remove pointless PMU disabling").

For the exact same reasons (i.e. perf core already does this around the
call anyway), give cci_pmu_add() the exact same change, which also
prevents having to export those core functions to build it as a module.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

perf/arm-cc*: Fix MODULE_LICENSE() tags

The CCI/CCN drivers are licensed under GPLv2, but the MODULE_LICENSE()
tags are using the bare "GPL" string implying GPLv2 or later. Fix them
to match their actual file license.

Acked-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

perf/arm-cci: Remove unnecessary period adjustment

Since sampling events are rejected up-front by cci_pmu_event_init(), it
doesn't make much sense to go fiddling with the sampling period later.
This would seem to be just another leftover artefact of the arm_pmu
framwork, and as such can go.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

perf/arm-cci: Untangle global cci_ctrl_base

Depending directly on the bus driver's global cci_ctrl_base variable
is a little unpleasant, and exporting it to allow the PMU driver to
be modular would be even more so. Let's make things a little better
abstracted by adding the control register block to the cci_pmu instance
data alongside the PMU register block, and communicating the mapped
address from the bus driver via platform data.

It's not practical to try the same thing for the bus driver itself,
given that the globals are entangled with the hairy assembly code for
port control, so we leave them be there. It would however be prudent
to move them to the __ro_after_init section in passing, since the
addresses really should never be changing once set.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

perf/arm-cci: Clean up model discovery

Since I am the self-appointed of_device_get_match_data() police, it's
only right that I should clean up this driver while I'm otherwise
touching it. This also reveals that we're passing around a struct
platform_device in places where we only ever care about its regular
device, so straighten that out in the process.

Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

perf/arm-cci: Simplify CPU hotplug

Realistically, systems with multiple CCIs are unlikely to ever exist,
and since the driver only actually supports a single instance anyway
there's really no need to do the multi-instance hotplug state dance.

Take the opportunity to simplify the hotplug-related code all over,
addressing the context-migration TODO in the process for good measure.

Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/bus: Split Arm CCI driver

The arm-cci driver is really two entirely separate drivers; one for MCPM
port control and the other for the performance monitors. Since they are
already relatively self-contained, let's take the plunge and move the
PMU parts out to drivers/perf where they belong these days. For non-MCPM
systems this leaves a small dependency on the remaining "bus" stub for
initial probing and discovery, but we end up with something that still
fits the general pattern of its fellow system PMU drivers to ease future
maintenance.

Moving code to a new file also offers a perfect excuse to modernise the
license/copyright headers and clean up some funky linewraps on the way.

Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>