xref: /openbmc/linux/drivers/base/Kconfig (revision cbdf59ad) 
1# SPDX-License-Identifier: GPL-2.0
2menu "Generic Driver Options"
3
4config UEVENT_HELPER
5	bool "Support for uevent helper"
6	help
7	  The uevent helper program is forked by the kernel for
8	  every uevent.
9	  Before the switch to the netlink-based uevent source, this was
10	  used to hook hotplug scripts into kernel device events. It
11	  usually pointed to a shell script at /sbin/hotplug.
12	  This should not be used today, because usual systems create
13	  many events at bootup or device discovery in a very short time
14	  frame. One forked process per event can create so many processes
15	  that it creates a high system load, or on smaller systems
16	  it is known to create out-of-memory situations during bootup.
17
18config UEVENT_HELPER_PATH
19	string "path to uevent helper"
20	depends on UEVENT_HELPER
21	default ""
22	help
23	  To disable user space helper program execution at by default
24	  specify an empty string here. This setting can still be altered
25	  via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper
26	  later at runtime.
27
28config DEVTMPFS
29	bool "Maintain a devtmpfs filesystem to mount at /dev"
30	help
31	  This creates a tmpfs/ramfs filesystem instance early at bootup.
32	  In this filesystem, the kernel driver core maintains device
33	  nodes with their default names and permissions for all
34	  registered devices with an assigned major/minor number.
35	  Userspace can modify the filesystem content as needed, add
36	  symlinks, and apply needed permissions.
37	  It provides a fully functional /dev directory, where usually
38	  udev runs on top, managing permissions and adding meaningful
39	  symlinks.
40	  In very limited environments, it may provide a sufficient
41	  functional /dev without any further help. It also allows simple
42	  rescue systems, and reliably handles dynamic major/minor numbers.
43
44	  Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs
45	  file system will be used instead.
46
47config DEVTMPFS_MOUNT
48	bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs"
49	depends on DEVTMPFS
50	help
51	  This will instruct the kernel to automatically mount the
52	  devtmpfs filesystem at /dev, directly after the kernel has
53	  mounted the root filesystem. The behavior can be overridden
54	  with the commandline parameter: devtmpfs.mount=0|1.
55	  This option does not affect initramfs based booting, here
56	  the devtmpfs filesystem always needs to be mounted manually
57	  after the rootfs is mounted.
58	  With this option enabled, it allows to bring up a system in
59	  rescue mode with init=/bin/sh, even when the /dev directory
60	  on the rootfs is completely empty.
61
62config STANDALONE
63	bool "Select only drivers that don't need compile-time external firmware"
64	default y
65	help
66	  Select this option if you don't have magic firmware for drivers that
67	  need it.
68
69	  If unsure, say Y.
70
71config PREVENT_FIRMWARE_BUILD
72	bool "Disable drivers features which enable custom firmware building"
73	default y
74	help
75	  Say yes to disable driver features which enable building a custom
76	  driver firmware at kernel build time. These drivers do not use the
77	  kernel firmware API to load firmware (CONFIG_FW_LOADER), instead they
78	  use their own custom loading mechanism. The required firmware is
79	  usually shipped with the driver, building the driver firmware
80	  should only be needed if you have an updated firmware source.
81
82	  Firmware should not be being built as part of kernel, these days
83	  you should always prevent this and say Y here. There are only two
84	  old drivers which enable building of its firmware at kernel build
85	  time:
86
87	    o CONFIG_WANXL through CONFIG_WANXL_BUILD_FIRMWARE
88	    o CONFIG_SCSI_AIC79XX through CONFIG_AIC79XX_BUILD_FIRMWARE
89
90source "drivers/base/firmware_loader/Kconfig"
91
92config WANT_DEV_COREDUMP
93	bool
94	help
95	  Drivers should "select" this option if they desire to use the
96	  device coredump mechanism.
97
98config ALLOW_DEV_COREDUMP
99	bool "Allow device coredump" if EXPERT
100	default y
101	help
102	  This option controls if the device coredump mechanism is available or
103	  not; if disabled, the mechanism will be omitted even if drivers that
104	  can use it are enabled.
105	  Say 'N' for more sensitive systems or systems that don't want
106	  to ever access the information to not have the code, nor keep any
107	  data.
108
109	  If unsure, say Y.
110
111config DEV_COREDUMP
112	bool
113	default y if WANT_DEV_COREDUMP
114	depends on ALLOW_DEV_COREDUMP
115
116config DEBUG_DRIVER
117	bool "Driver Core verbose debug messages"
118	depends on DEBUG_KERNEL
119	help
120	  Say Y here if you want the Driver core to produce a bunch of
121	  debug messages to the system log. Select this if you are having a
122	  problem with the driver core and want to see more of what is
123	  going on.
124
125	  If you are unsure about this, say N here.
126
127config DEBUG_DEVRES
128	bool "Managed device resources verbose debug messages"
129	depends on DEBUG_KERNEL
130	help
131	  This option enables kernel parameter devres.log. If set to
132	  non-zero, devres debug messages are printed. Select this if
133	  you are having a problem with devres or want to debug
134	  resource management for a managed device. devres.log can be
135	  switched on and off from sysfs node.
136
137	  If you are unsure about this, Say N here.
138
139config DEBUG_TEST_DRIVER_REMOVE
140	bool "Test driver remove calls during probe (UNSTABLE)"
141	depends on DEBUG_KERNEL
142	help
143	  Say Y here if you want the Driver core to test driver remove functions
144	  by calling probe, remove, probe. This tests the remove path without
145	  having to unbind the driver or unload the driver module.
146
147	  This option is expected to find errors and may render your system
148	  unusable. You should say N here unless you are explicitly looking to
149	  test this functionality.
150
151config HMEM_REPORTING
152	bool
153	default n
154	depends on NUMA
155	help
156	  Enable reporting for heterogenous memory access attributes under
157	  their non-uniform memory nodes.
158
159source "drivers/base/test/Kconfig"
160
161config SYS_HYPERVISOR
162	bool
163	default n
164
165config GENERIC_CPU_DEVICES
166	bool
167	default n
168
169config GENERIC_CPU_AUTOPROBE
170	bool
171
172config GENERIC_CPU_VULNERABILITIES
173	bool
174
175config SOC_BUS
176	bool
177	select GLOB
178
179source "drivers/base/regmap/Kconfig"
180
181config DMA_SHARED_BUFFER
182	bool
183	default n
184	select IRQ_WORK
185	help
186	  This option enables the framework for buffer-sharing between
187	  multiple drivers. A buffer is associated with a file using driver
188	  APIs extension; the file's descriptor can then be passed on to other
189	  driver.
190
191config DMA_FENCE_TRACE
192	bool "Enable verbose DMA_FENCE_TRACE messages"
193	depends on DMA_SHARED_BUFFER
194	help
195	  Enable the DMA_FENCE_TRACE printks. This will add extra
196	  spam to the console log, but will make it easier to diagnose
197	  lockup related problems for dma-buffers shared across multiple
198	  devices.
199
200config GENERIC_ARCH_TOPOLOGY
201	bool
202	help
203	  Enable support for architectures common topology code: e.g., parsing
204	  CPU capacity information from DT, usage of such information for
205	  appropriate scaling, sysfs interface for changing capacity values at
206	  runtime.
207
208endmenu
209