linux.git/drivers/base/init.c, branch v7.1-rc2

driver core: make software nodes available earlier

2026-04-03T22:33:49+00:00

Software nodes are currently initialized in a function registered as
a postcore_initcall(). However, some devices may want to register
software nodes earlier than that (or also in a postcore_initcall() where
they're at the mercy of the link order). Move the initialization to
driver_init() making swnode available much earlier as well as making
their initialization time deterministic.

Suggested-by: Dmitry Torokhov 
Signed-off-by: Bartosz Golaszewski 
Acked-by: Andy Shevchenko 
Link: https://patch.msgid.link/20260402-nokia770-gpio-swnodes-v5-3-d730db3dd299@oss.qualcomm.com
[ Fix typo in the commit message: "s/merci/mercy/". - Danilo ]
Signed-off-by: Danilo Krummrich

driver core: add a faux bus for use when a simple device/bus is needed

2025-02-13T15:58:51+00:00

Many drivers abuse the platform driver/bus system as it provides a
simple way to create and bind a device to a driver-specific set of
probe/release functions.  Instead of doing that, and wasting all of the
memory associated with a platform device, here is a "faux" bus that
can be used instead.

Reviewed-by: Jonathan Cameron 
Reviewed-by: Danilo Krummrich 
Reviewed-by: Lyude Paul 
Reviewed-by: Thomas Weißschuh 
Reviewed-by: Zijun Hu 
Link: https://lore.kernel.org/r/2025021026-atlantic-gibberish-3f0c@gregkh
Signed-off-by: Greg Kroah-Hartman

drivers: base: Move cpu_dev_init() after node_dev_init()

2023-12-06T03:41:49+00:00

NUMA systems require the node descriptions to be ready before CPUs are
registered. This is so that the node symlinks can be created in sysfs.

Currently no NUMA platform uses GENERIC_CPU_DEVICES, meaning that CPUs
are registered by arch code, instead of cpu_dev_init().

Move cpu_dev_init() after node_dev_init() so that NUMA architectures
can use GENERIC_CPU_DEVICES.

Signed-off-by: James Morse 
Signed-off-by: "Russell King (Oracle)" 
Reviewed-by: Gavin Shan 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/E1r5R3R-00CszO-C0@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman

init: Initialize noop_backing_dev_info early

2022-06-16T08:55:57+00:00

noop_backing_dev_info is used by superblocks of various
pseudofilesystems such as kdevtmpfs. After commit 10e14073107d
("writeback: Fix inode->i_io_list not be protected by inode->i_lock
error") this broke because __mark_inode_dirty() started to access more
fields from noop_backing_dev_info and this led to crashes inside
locked_inode_to_wb_and_lock_list() called from __mark_inode_dirty().
Fix the problem by initializing noop_backing_dev_info before the
filesystems get mounted.

Fixes: 10e14073107d ("writeback: Fix inode->i_io_list not be protected by inode->i_lock error")
Reported-and-tested-by: Suzuki K Poulose 
Reported-and-tested-by: Alexandru Elisei 
Reported-and-tested-by: Guenter Roeck 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jan Kara

drivers/base/node: consolidate node device subsystem initialization in node_dev_init()

2022-03-22T22:57:10+00:00

...  and call node_dev_init() after memory_dev_init() from driver_init(),
so before any of the existing arch/subsys calls.  All online nodes should
be known at that point: early during boot, arch code determines node and
zone ranges and sets the relevant nodes online; usually this happens in
setup_arch().

This is in line with memory_dev_init(), which initializes the memory
device subsystem and creates all memory block devices.

Similar to memory_dev_init(), panic() if anything goes wrong, we don't
want to continue with such basic initialization errors.

The important part is that node_dev_init() gets called after
memory_dev_init() and after cpu_dev_init(), but before any of the relevant
archs call register_cpu() to register the new cpu device under the node
device.  The latter should be the case for the current users of
topology_init().

Link: https://lkml.kernel.org/r/20220203105212.30385-1-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Oscar Salvador 
Tested-by: Anatoly Pugachev  (sparc64)
Cc: Greg Kroah-Hartman 
Cc: Michal Hocko 
Cc: Oscar Salvador 
Cc: Mike Rapoport 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Thomas Bogendoerfer 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Paul Walmsley 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Heiko Carstens 
Cc: Vasily Gorbik 
Cc: Yoshinori Sato 
Cc: Rich Felker 
Cc: "David S. Miller" 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: "Rafael J. Wysocki" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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

2021-02-11T07:43:03+00:00

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 
Reviewed-by: Dan Williams 
Acked-by: Dave Ertman 
Signed-off-by: Dave Jiang 
Link: https://lore.kernel.org/r/20210210201611.1611074-1-dave.jiang@intel.com
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

base: fix order of OF initialization

2018-07-07T15:54:29+00:00

This fixes: [    0.010000] cpu cpu0: Error -2 creating of_node link
... which you get for every CPU on all architectures that use
CONFIG_GENERIC_CPU_DEVICES.

In that case, driver_init() calls cpu_dev_init() before calling
of_core_init(). Then we get the callchain:

  cpu_dev_init()
    -> cpu_dev_register_generic()
    -> register_cpu(cpu, i)
    -> device_register(&cpu->dev)
    -> device_add(dev)
    -> device_add_class_symlinks(dev)

... in device_add_class_symlinks, we we dev->of_node, and call
sysfs_create_link(), which fails because we haven't called
of_core_init() to register the sysfs devicetree directory yet.

Signed-off-by: Wesley W. Terpstra 
[hch: updated the changelog based on review feedback]
Signed-off-by: Christoph Hellwig 
Acked-by: Mark Rutland 
Acked-by: Frank Rowand 
Signed-off-by: Greg Kroah-Hartman

driver core: Remove redundant license text

2017-12-07T17:36:44+00:00

Now that the SPDX tag is in all driver core files, that identifies the
license in a specific and legally-defined manner.  So the extra GPL text
wording can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text.  And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Johannes Berg 
Cc: "Luis R. Rodriguez" 
Signed-off-by: Greg Kroah-Hartman

driver core: add SPDX identifiers to all driver core files

2017-12-07T17:36:43+00:00

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the driver core files files with the correct SPDX license
identifier based on the license text in the file itself.  The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Johannes Berg 
Cc: "Luis R. Rodriguez" 
Cc: William Breathitt Gray 
Cc: Thomas Gleixner 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Signed-off-by: Greg Kroah-Hartman

drivers: of/base: move of_init to driver_init

2015-05-27T02:55:56+00:00

Commit 5590f3196b29 ("drivers/core/of: Add symlink to device-tree from
devices with an OF node") adds the symlink `of_node` for each device
pointing to it's device tree node while creating/initialising it.

However the devicetree sysfs is created and setup in of_init which is
executed at core_initcall level. For all the devices created before
of_init, the following error is thrown:
	"Error -2(-ENOENT) creating of_node link"

Like many other components in driver model, initialize the sysfs support
for OF/devicetree from driver_init so that it's ready before any devices
are created.

Fixes: 5590f3196b29 ("drivers/core/of: Add symlink to device-tree from
	devices with an OF node")
Suggested-by: Rob Herring 
Cc: Grant Likely 
Cc: Pawel Moll 
Cc: Benjamin Herrenschmidt 
Signed-off-by: Sudeep Holla 
Tested-by: Robert Schwebel 
Acked-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman