driver core: mark remaining local bus_type variables as const

Now that the driver core can properly handle constant struct bus_type,
change the local driver core bus_type variables to be a constant
structure as well, placing them into read-only memory which can not be
modified at runtime.

Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Len Brown <len.brown@intel.com>
Acked-by: William Breathitt Gray <william.gray@linaro.org>
Acked-by: Dave Ertman <david.m.ertman@intel.com>
Link: https://lore.kernel.org/r/2023121908-paver-follow-cc21@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: make struct bus_type.uevent() take a const *

The uevent() callback in struct bus_type should not be modifying the
device that is passed into it, so mark it as a const * and propagate the
function signature changes out into all relevant subsystems that use
this callback.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-16-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/auxiliary_bus: Move the text into the code

The code and documentation are more difficult to maintain when kept
separately. This is further compounded when the standard structure
documentation infrastructure is not used.

Move the documentation into the code, use the standard documentation
infrastructure, add current documented functions, and reference the text
in the rst file.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20211202044305.4006853-8-ira.weiny@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/auxiliary_bus: Clarify the release of devices from find device

auxiliary_find_device() takes a proper get_device() reference on the
device before returning the matched device.

Users of this call should be informed that they need to properly release
this reference with put_device().

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20211202044305.4006853-7-ira.weiny@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/auxiliary_bus: Clarify __auxiliary_driver_register

__auxiliary_driver_register is not intended to be called directly unless
a custom name is required. Add documentation for this fact.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20211202044305.4006853-5-ira.weiny@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/auxiliary_bus: Clarify auxiliary_device creation

The documentation for creating an auxiliary device is a 3 step not a 2
step process. Specifically the requirements of setting the name, id,
dev.release, and dev.parent fields was not clear as a precursor to the '2
step' process documented.

Clarify by declaring this a 3 step process starting with setting the
fields of struct auxiliary_device correctly.

Also add some sample code and tie the change into the rest of the
documentation.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20211202044305.4006853-2-ira.weiny@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

bus: Make remove callback return void

The driver core ignores the return value of this callback because there
is only little it can do when a device disappears.

This is the final bit of a long lasting cleanup quest where several
buses were converted to also return void from their remove callback.
Additionally some resource leaks were fixed that were caused by drivers
returning an error code in the expectation that the driver won't go
away.

With struct bus_type::remove returning void it's prevented that newly
implemented buses return an ignored error code and so don't anticipate
wrong expectations for driver authors.

Reviewed-by: Tom Rix <trix@redhat.com> (For fpga)
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com> (For drivers/s390 and drivers/vfio)
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> (For ARM, Amba and related parts)
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Chen-Yu Tsai <wens@csie.org> (for sunxi-rsb)
Acked-by: Pali Rohár <pali@kernel.org>
Acked-by: Mauro Carvalho Chehab <mchehab@kernel.org> (for media)
Acked-by: Hans de Goede <hdegoede@redhat.com> (For drivers/platform)
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Acked-by: Juergen Gross <jgross@suse.com> (For xen)
Acked-by: Lee Jones <lee.jones@linaro.org> (For mfd)
Acked-by: Johannes Thumshirn <jth@kernel.org> (For mcb)
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> (For slimbus)
Acked-by: Kirti Wankhede <kwankhede@nvidia.com> (For vfio)
Acked-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> (For ulpi and typec)
Acked-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com> (For ipack)
Acked-by: Geoff Levand <geoff@infradead.org> (For ps3)
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com> (For thunderbolt)
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> (For intel_th)
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net> (For pcmcia)
Acked-by: Rafael J. Wysocki <rafael@kernel.org> (For ACPI)
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> (rpmsg and apr)
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> (For intel-ish-hid)
Acked-by: Dan Williams <dan.j.williams@intel.com> (For CXL, DAX, and NVDIMM)
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> (For isa)
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (For firewire)
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> (For hid)
Acked-by: Thorsten Scherer <t.scherer@eckelmann.de> (For siox)
Acked-by: Sven Van Asbroeck <TheSven73@gmail.com> (For anybuss)
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> (For MMC)
Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Finn Thain <fthain@linux-m68k.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210713193522.1770306-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: auxiliary bus: Fix memory leak when driver_register() fail

If driver_register() returns with error we need to free the memory
allocated for auxdrv->driver.name before returning from
__auxiliary_driver_register()

Fixes: 7de3697e9cbd4 ("Add auxiliary bus support")
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20210713093438.3173-1-peter.ujfalusi@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: auxiliary bus: Remove unneeded module bits

Remove module bits in the auxiliary bus code since the auxiliary bus
cannot be built as a module and the relevant code is not needed.

Cc: Dave Ertman <david.m.ertman@intel.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/161307488980.1896017.15627190714413338196.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: auxiliary bus: Fix calling stage for auxiliary bus init

When the auxiliary device code is built into the kernel, it can be executed
before the auxiliary bus is registered. This causes bus->p to be not
allocated and triggers a NULL pointer dereference when the auxiliary bus
device gets added with bus_add_device(). Call the auxiliary_bus_init()
under driver_init() so the bus is initialized before devices.

Below is the kernel splat for the bug:
[ 1.948215] BUG: kernel NULL pointer dereference, address: 0000000000000060
[ 1.950670] #PF: supervisor read access in kernel mode
[ 1.950670] #PF: error_code(0x0000) - not-present page
[ 1.950670] PGD 0
[ 1.950670] Oops: 0000 1 SMP NOPTI
[ 1.950670] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.0-intel-nextsvmtest+ #2205
[ 1.950670] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 1.950670] RIP: 0010:bus_add_device+0x64/0x140
[ 1.950670] Code: 00 49 8b 75 20 48 89 df e8 59 a1 ff ff 41 89 c4 85 c0 75 7b 48 8b 53 50 48 85 d2 75 03 48 8b 13 49 8b 85 a0 00 00 00 48 89 de <48> 8
78 60 48 83 c7 18 e8 ef d9 a9 ff 41 89 c4 85 c0 75 45 48 8b
[ 1.950670] RSP: 0000:ff46032ac001baf8 EFLAGS: 00010246
[ 1.950670] RAX: 0000000000000000 RBX: ff4597f7414aa680 RCX: 0000000000000000
[ 1.950670] RDX: ff4597f74142bbc0 RSI: ff4597f7414aa680 RDI: ff4597f7414aa680
[ 1.950670] RBP: ff46032ac001bb10 R08: 0000000000000044 R09: 0000000000000228
[ 1.950670] R10: ff4597f741141b30 R11: ff4597f740182a90 R12: 0000000000000000
[ 1.950670] R13: ffffffffa5e936c0 R14: 0000000000000000 R15: 0000000000000000
[ 1.950670] FS: 0000000000000000(0000) GS:ff4597f7bba00000(0000) knlGS:0000000000000000
[ 1.950670] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1.950670] CR2: 0000000000000060 CR3: 000000002140c001 CR4: 0000000000f71ef0
[ 1.950670] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1.950670] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
[ 1.950670] PKRU: 55555554
[ 1.950670] Call Trace:
[ 1.950670] device_add+0x3ee/0x850
[ 1.950670] __auxiliary_device_add+0x47/0x60
[ 1.950670] idxd_pci_probe+0xf77/0x1180
[ 1.950670] local_pci_probe+0x4a/0x90
[ 1.950670] pci_device_probe+0xff/0x1b0
[ 1.950670] really_probe+0x1cf/0x440
[ 1.950670] ? rdinit_setup+0x31/0x31
[ 1.950670] driver_probe_device+0xe8/0x150
[ 1.950670] device_driver_attach+0x58/0x60
[ 1.950670] __driver_attach+0x8f/0x150
[ 1.950670] ? device_driver_attach+0x60/0x60
[ 1.950670] ? device_driver_attach+0x60/0x60
[ 1.950670] bus_for_each_dev+0x79/0xc0
[ 1.950670] ? kmem_cache_alloc_trace+0x323/0x430
[ 1.950670] driver_attach+0x1e/0x20
[ 1.950670] bus_add_driver+0x154/0x1f0
[ 1.950670] driver_register+0x70/0xc0
[ 1.950670] __pci_register_driver+0x54/0x60
[ 1.950670] idxd_init_module+0xe2/0xfc
[ 1.950670] ? idma64_platform_driver_init+0x19/0x19
[ 1.950670] do_one_initcall+0x4a/0x1e0
[ 1.950670] kernel_init_freeable+0x1fc/0x25c
[ 1.950670] ? rest_init+0xba/0xba
[ 1.950670] kernel_init+0xe/0x116
[ 1.950670] ret_from_fork+0x1f/0x30
[ 1.950670] Modules linked in:
[ 1.950670] CR2: 0000000000000060
[ 1.950670] --[ end trace cd7d1b226d3ca901 ]--

Fixes: 7de3697e9cbd ("Add auxiliary bus support")
Reported-by: Jacob Pan <jacob.jun.pan@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Dave Ertman <david.m.ertman@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20210210201611.1611074-1-dave.jiang@intel.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: auxiliary bus: Fix auxiliary bus shutdown null auxdrv ptr

If the probe of the auxdrv failed, the device->driver is set to NULL.
During kernel shutdown, the bus shutdown will call auxdrv->shutdown and
cause an invalid ptr dereference. Add check to make sure device->driver is
not NULL before we proceed.

Fixes: 7de3697e9cbd ("Add auxiliary bus support")
Cc: Dave Ertman <david.m.ertman@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/160710040926.1889434.8840329810698403478.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: auxiliary bus: minor coding style tweaks

For some reason, the original aux bus patch had some really long lines
in a few places, probably due to it being a very long-lived patch in
development by many different people. Fix that up so that the two files
all have the same length lines and function formatting styles.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Ertman <david.m.ertman@intel.com>
Cc: Fred Oh <fred.oh@linux.intel.com>
Cc: Kiran Patil <kiran.patil@intel.com>
Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: Martin Habets <mhabets@solarflare.com>
Cc: Parav Pandit <parav@mellanox.com>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Cc: Shiraz Saleem <shiraz.saleem@intel.com>
Link: https://lore.kernel.org/r/X8oiSFTpYHw1xE/o@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: auxiliary bus: make remove function return void

There's an effort to move the remove() callback in the driver core to
not return an int, as nothing can be done if this function fails. To
make that effort easier, make the aux bus remove function void to start
with so that no users have to be changed sometime in the future.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Ertman <david.m.ertman@intel.com>
Cc: Fred Oh <fred.oh@linux.intel.com>
Cc: Kiran Patil <kiran.patil@intel.com>
Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: Martin Habets <mhabets@solarflare.com>
Cc: Parav Pandit <parav@mellanox.com>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Cc: Shiraz Saleem <shiraz.saleem@intel.com>
Link: https://lore.kernel.org/r/X8ohB1ks1NK7kPop@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: auxiliary bus: move slab.h from include file

No need to include slab.h in include/linux/auxiliary_bus.h, as it is not
needed there. Move it to drivers/base/auxiliary.c instead.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Ertman <david.m.ertman@intel.com>
Cc: Fred Oh <fred.oh@linux.intel.com>
Cc: Kiran Patil <kiran.patil@intel.com>
Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: Martin Habets <mhabets@solarflare.com>
Cc: Parav Pandit <parav@mellanox.com>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Cc: Shiraz Saleem <shiraz.saleem@intel.com>
Link: https://lore.kernel.org/r/X8og8xi3WkoYXet9@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add auxiliary bus support

Add support for the Auxiliary Bus, auxiliary_device and auxiliary_driver.
It enables drivers to create an auxiliary_device and bind an
auxiliary_driver to it.

The bus supports probe/remove shutdown and suspend/resume callbacks.
Each auxiliary_device has a unique string based id; driver binds to
an auxiliary_device based on this id through the bus.

Co-developed-by: Kiran Patil <kiran.patil@intel.com>
Co-developed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Co-developed-by: Fred Oh <fred.oh@linux.intel.com>
Co-developed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Kiran Patil <kiran.patil@intel.com>
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Fred Oh <fred.oh@linux.intel.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Martin Habets <mhabets@solarflare.com>
Link: https://lore.kernel.org/r/20201113161859.1775473-2-david.m.ertman@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/160695681289.505290.8978295443574440604.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>