xref: /openbmc/linux/drivers/base/Kconfig (revision aec499c7)
1# SPDX-License-Identifier: GPL-2.0
2menu "Generic Driver Options"
3
4config AUXILIARY_BUS
5	bool
6
7config UEVENT_HELPER
8	bool "Support for uevent helper"
9	help
10	  The uevent helper program is forked by the kernel for
11	  every uevent.
12	  Before the switch to the netlink-based uevent source, this was
13	  used to hook hotplug scripts into kernel device events. It
14	  usually pointed to a shell script at /sbin/hotplug.
15	  This should not be used today, because usual systems create
16	  many events at bootup or device discovery in a very short time
17	  frame. One forked process per event can create so many processes
18	  that it creates a high system load, or on smaller systems
19	  it is known to create out-of-memory situations during bootup.
20
21config UEVENT_HELPER_PATH
22	string "path to uevent helper"
23	depends on UEVENT_HELPER
24	default ""
25	help
26	  To disable user space helper program execution at by default
27	  specify an empty string here. This setting can still be altered
28	  via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper
29	  later at runtime.
30
31config DEVTMPFS
32	bool "Maintain a devtmpfs filesystem to mount at /dev"
33	help
34	  This creates a tmpfs/ramfs filesystem instance early at bootup.
35	  In this filesystem, the kernel driver core maintains device
36	  nodes with their default names and permissions for all
37	  registered devices with an assigned major/minor number.
38	  Userspace can modify the filesystem content as needed, add
39	  symlinks, and apply needed permissions.
40	  It provides a fully functional /dev directory, where usually
41	  udev runs on top, managing permissions and adding meaningful
42	  symlinks.
43	  In very limited environments, it may provide a sufficient
44	  functional /dev without any further help. It also allows simple
45	  rescue systems, and reliably handles dynamic major/minor numbers.
46
47	  Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs
48	  file system will be used instead.
49
50config DEVTMPFS_MOUNT
51	bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs"
52	depends on DEVTMPFS
53	help
54	  This will instruct the kernel to automatically mount the
55	  devtmpfs filesystem at /dev, directly after the kernel has
56	  mounted the root filesystem. The behavior can be overridden
57	  with the commandline parameter: devtmpfs.mount=0|1.
58	  This option does not affect initramfs based booting, here
59	  the devtmpfs filesystem always needs to be mounted manually
60	  after the rootfs is mounted.
61	  With this option enabled, it allows to bring up a system in
62	  rescue mode with init=/bin/sh, even when the /dev directory
63	  on the rootfs is completely empty.
64
65config DEVTMPFS_SAFE
66	bool "Use nosuid,noexec mount options on devtmpfs"
67	depends on DEVTMPFS
68	help
69	  This instructs the kernel to include the MS_NOEXEC and MS_NOSUID mount
70	  flags when mounting devtmpfs.
71
72	  Notice: If enabled, things like /dev/mem cannot be mmapped
73	  with the PROT_EXEC flag. This can break, for example, non-KMS
74	  video drivers.
75
76config STANDALONE
77	bool "Select only drivers that don't need compile-time external firmware"
78	default y
79	help
80	  Select this option if you don't have magic firmware for drivers that
81	  need it.
82
83	  If unsure, say Y.
84
85config PREVENT_FIRMWARE_BUILD
86	bool "Disable drivers features which enable custom firmware building"
87	default y
88	help
89	  Say yes to disable driver features which enable building a custom
90	  driver firmware at kernel build time. These drivers do not use the
91	  kernel firmware API to load firmware (CONFIG_FW_LOADER), instead they
92	  use their own custom loading mechanism. The required firmware is
93	  usually shipped with the driver, building the driver firmware
94	  should only be needed if you have an updated firmware source.
95
96	  Firmware should not be being built as part of kernel, these days
97	  you should always prevent this and say Y here. There are only two
98	  old drivers which enable building of its firmware at kernel build
99	  time:
100
101	    o CONFIG_WANXL through CONFIG_WANXL_BUILD_FIRMWARE
102	    o CONFIG_SCSI_AIC79XX through CONFIG_AIC79XX_BUILD_FIRMWARE
103
104source "drivers/base/firmware_loader/Kconfig"
105
106config WANT_DEV_COREDUMP
107	bool
108	help
109	  Drivers should "select" this option if they desire to use the
110	  device coredump mechanism.
111
112config ALLOW_DEV_COREDUMP
113	bool "Allow device coredump" if EXPERT
114	default y
115	help
116	  This option controls if the device coredump mechanism is available or
117	  not; if disabled, the mechanism will be omitted even if drivers that
118	  can use it are enabled.
119	  Say 'N' for more sensitive systems or systems that don't want
120	  to ever access the information to not have the code, nor keep any
121	  data.
122
123	  If unsure, say Y.
124
125config DEV_COREDUMP
126	bool
127	default y if WANT_DEV_COREDUMP
128	depends on ALLOW_DEV_COREDUMP
129
130config DEBUG_DRIVER
131	bool "Driver Core verbose debug messages"
132	depends on DEBUG_KERNEL
133	help
134	  Say Y here if you want the Driver core to produce a bunch of
135	  debug messages to the system log. Select this if you are having a
136	  problem with the driver core and want to see more of what is
137	  going on.
138
139	  If you are unsure about this, say N here.
140
141config DEBUG_DEVRES
142	bool "Managed device resources verbose debug messages"
143	depends on DEBUG_KERNEL
144	help
145	  This option enables kernel parameter devres.log. If set to
146	  non-zero, devres debug messages are printed. Select this if
147	  you are having a problem with devres or want to debug
148	  resource management for a managed device. devres.log can be
149	  switched on and off from sysfs node.
150
151	  If you are unsure about this, Say N here.
152
153config DEBUG_TEST_DRIVER_REMOVE
154	bool "Test driver remove calls during probe (UNSTABLE)"
155	depends on DEBUG_KERNEL
156	help
157	  Say Y here if you want the Driver core to test driver remove functions
158	  by calling probe, remove, probe. This tests the remove path without
159	  having to unbind the driver or unload the driver module.
160
161	  This option is expected to find errors and may render your system
162	  unusable. You should say N here unless you are explicitly looking to
163	  test this functionality.
164
165config PM_QOS_KUNIT_TEST
166	bool "KUnit Test for PM QoS features" if !KUNIT_ALL_TESTS
167	depends on KUNIT=y
168	default KUNIT_ALL_TESTS
169
170config HMEM_REPORTING
171	bool
172	default n
173	depends on NUMA
174	help
175	  Enable reporting for heterogeneous memory access attributes under
176	  their non-uniform memory nodes.
177
178source "drivers/base/test/Kconfig"
179
180config SYS_HYPERVISOR
181	bool
182	default n
183
184config GENERIC_CPU_DEVICES
185	bool
186	default n
187
188config GENERIC_CPU_AUTOPROBE
189	bool
190
191config GENERIC_CPU_VULNERABILITIES
192	bool
193
194config SOC_BUS
195	bool
196	select GLOB
197
198source "drivers/base/regmap/Kconfig"
199
200config DMA_SHARED_BUFFER
201	bool
202	default n
203	select IRQ_WORK
204	help
205	  This option enables the framework for buffer-sharing between
206	  multiple drivers. A buffer is associated with a file using driver
207	  APIs extension; the file's descriptor can then be passed on to other
208	  driver.
209
210config DMA_FENCE_TRACE
211	bool "Enable verbose DMA_FENCE_TRACE messages"
212	depends on DMA_SHARED_BUFFER
213	help
214	  Enable the DMA_FENCE_TRACE printks. This will add extra
215	  spam to the console log, but will make it easier to diagnose
216	  lockup related problems for dma-buffers shared across multiple
217	  devices.
218
219config GENERIC_ARCH_TOPOLOGY
220	bool
221	help
222	  Enable support for architectures common topology code: e.g., parsing
223	  CPU capacity information from DT, usage of such information for
224	  appropriate scaling, sysfs interface for reading capacity values at
225	  runtime.
226
227config GENERIC_ARCH_NUMA
228	bool
229	help
230	  Enable support for generic NUMA implementation. Currently, RISC-V
231	  and ARM64 use it.
232
233endmenu
234