xref: /openbmc/linux/drivers/base/Kconfig (revision f9a82c48) 
1# SPDX-License-Identifier: GPL-2.0
2menu "Generic Driver Options"
3
4config UEVENT_HELPER
5	bool "Support for uevent helper"
6	default y
7	help
8	  The uevent helper program is forked by the kernel for
9	  every uevent.
10	  Before the switch to the netlink-based uevent source, this was
11	  used to hook hotplug scripts into kernel device events. It
12	  usually pointed to a shell script at /sbin/hotplug.
13	  This should not be used today, because usual systems create
14	  many events at bootup or device discovery in a very short time
15	  frame. One forked process per event can create so many processes
16	  that it creates a high system load, or on smaller systems
17	  it is known to create out-of-memory situations during bootup.
18
19config UEVENT_HELPER_PATH
20	string "path to uevent helper"
21	depends on UEVENT_HELPER
22	default ""
23	help
24	  To disable user space helper program execution at by default
25	  specify an empty string here. This setting can still be altered
26	  via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper
27	  later at runtime.
28
29config DEVTMPFS
30	bool "Maintain a devtmpfs filesystem to mount at /dev"
31	help
32	  This creates a tmpfs/ramfs filesystem instance early at bootup.
33	  In this filesystem, the kernel driver core maintains device
34	  nodes with their default names and permissions for all
35	  registered devices with an assigned major/minor number.
36	  Userspace can modify the filesystem content as needed, add
37	  symlinks, and apply needed permissions.
38	  It provides a fully functional /dev directory, where usually
39	  udev runs on top, managing permissions and adding meaningful
40	  symlinks.
41	  In very limited environments, it may provide a sufficient
42	  functional /dev without any further help. It also allows simple
43	  rescue systems, and reliably handles dynamic major/minor numbers.
44
45	  Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs
46	  file system will be used instead.
47
48config DEVTMPFS_MOUNT
49	bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs"
50	depends on DEVTMPFS
51	help
52	  This will instruct the kernel to automatically mount the
53	  devtmpfs filesystem at /dev, directly after the kernel has
54	  mounted the root filesystem. The behavior can be overridden
55	  with the commandline parameter: devtmpfs.mount=0|1.
56	  This option does not affect initramfs based booting, here
57	  the devtmpfs filesystem always needs to be mounted manually
58	  after the rootfs is mounted.
59	  With this option enabled, it allows to bring up a system in
60	  rescue mode with init=/bin/sh, even when the /dev directory
61	  on the rootfs is completely empty.
62
63config STANDALONE
64	bool "Select only drivers that don't need compile-time external firmware"
65	default y
66	help
67	  Select this option if you don't have magic firmware for drivers that
68	  need it.
69
70	  If unsure, say Y.
71
72config PREVENT_FIRMWARE_BUILD
73	bool "Disable drivers features which enable custom firmware building"
74	default y
75	help
76	  Say yes to disable driver features which enable building a custom
77	  driver firmware at kernel build time. These drivers do not use the
78	  kernel firmware API to load firmware (CONFIG_FW_LOADER), instead they
79	  use their own custom loading mechanism. The required firmware is
80	  usually shipped with the driver, building the driver firmware
81	  should only be needed if you have an updated firmware source.
82
83	  Firmware should not be being built as part of kernel, these days
84	  you should always prevent this and say Y here. There are only two
85	  old drivers which enable building of its firmware at kernel build
86	  time:
87
88	    o CONFIG_WANXL through CONFIG_WANXL_BUILD_FIRMWARE
89	    o CONFIG_SCSI_AIC79XX through CONFIG_AIC79XX_BUILD_FIRMWARE
90
91source "drivers/base/firmware_loader/Kconfig"
92
93config WANT_DEV_COREDUMP
94	bool
95	help
96	  Drivers should "select" this option if they desire to use the
97	  device coredump mechanism.
98
99config ALLOW_DEV_COREDUMP
100	bool "Allow device coredump" if EXPERT
101	default y
102	help
103	  This option controls if the device coredump mechanism is available or
104	  not; if disabled, the mechanism will be omitted even if drivers that
105	  can use it are enabled.
106	  Say 'N' for more sensitive systems or systems that don't want
107	  to ever access the information to not have the code, nor keep any
108	  data.
109
110	  If unsure, say Y.
111
112config DEV_COREDUMP
113	bool
114	default y if WANT_DEV_COREDUMP
115	depends on ALLOW_DEV_COREDUMP
116
117config DEBUG_DRIVER
118	bool "Driver Core verbose debug messages"
119	depends on DEBUG_KERNEL
120	help
121	  Say Y here if you want the Driver core to produce a bunch of
122	  debug messages to the system log. Select this if you are having a
123	  problem with the driver core and want to see more of what is
124	  going on.
125
126	  If you are unsure about this, say N here.
127
128config DEBUG_DEVRES
129	bool "Managed device resources verbose debug messages"
130	depends on DEBUG_KERNEL
131	help
132	  This option enables kernel parameter devres.log. If set to
133	  non-zero, devres debug messages are printed. Select this if
134	  you are having a problem with devres or want to debug
135	  resource management for a managed device. devres.log can be
136	  switched on and off from sysfs node.
137
138	  If you are unsure about this, Say N here.
139
140config DEBUG_TEST_DRIVER_REMOVE
141	bool "Test driver remove calls during probe (UNSTABLE)"
142	depends on DEBUG_KERNEL
143	help
144	  Say Y here if you want the Driver core to test driver remove functions
145	  by calling probe, remove, probe. This tests the remove path without
146	  having to unbind the driver or unload the driver module.
147
148	  This option is expected to find errors and may render your system
149	  unusable. You should say N here unless you are explicitly looking to
150	  test this functionality.
151
152source "drivers/base/test/Kconfig"
153
154config SYS_HYPERVISOR
155	bool
156	default n
157
158config GENERIC_CPU_DEVICES
159	bool
160	default n
161
162config GENERIC_CPU_AUTOPROBE
163	bool
164
165config GENERIC_CPU_VULNERABILITIES
166	bool
167
168config SOC_BUS
169	bool
170	select GLOB
171
172source "drivers/base/regmap/Kconfig"
173
174config DMA_SHARED_BUFFER
175	bool
176	default n
177	select ANON_INODES
178	select IRQ_WORK
179	help
180	  This option enables the framework for buffer-sharing between
181	  multiple drivers. A buffer is associated with a file using driver
182	  APIs extension; the file's descriptor can then be passed on to other
183	  driver.
184
185config DMA_FENCE_TRACE
186	bool "Enable verbose DMA_FENCE_TRACE messages"
187	depends on DMA_SHARED_BUFFER
188	help
189	  Enable the DMA_FENCE_TRACE printks. This will add extra
190	  spam to the console log, but will make it easier to diagnose
191	  lockup related problems for dma-buffers shared across multiple
192	  devices.
193
194config GENERIC_ARCH_TOPOLOGY
195	bool
196	help
197	  Enable support for architectures common topology code: e.g., parsing
198	  CPU capacity information from DT, usage of such information for
199	  appropriate scaling, sysfs interface for changing capacity values at
200	  runtime.
201
202endmenu
203