tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 "Prevent firmware from being built"
74 default y
75 help
76 Say yes to avoid building firmware. Firmware is usually shipped
77 with the driver and only when updating the firmware should a
78 rebuild be made.
79 If unsure, say Y here.
80
81config FW_LOADER
82 tristate "Userspace firmware loading support" if EXPERT
83 default y
84 ---help---
85 This option is provided for the case where none of the in-tree modules
86 require userspace firmware loading support, but a module built
87 out-of-tree does.
88
89config EXTRA_FIRMWARE
90 string "External firmware blobs to build into the kernel binary"
91 depends on FW_LOADER
92 help
93 Various drivers in the kernel source tree may require firmware,
94 which is generally available in your distribution's linux-firmware
95 package.
96
97 The linux-firmware package should install firmware into
98 /lib/firmware/ on your system, so they can be loaded by userspace
99 helpers on request.
100
101 This option allows firmware to be built into the kernel for the case
102 where the user either cannot or doesn't want to provide it from
103 userspace at runtime (for example, when the firmware in question is
104 required for accessing the boot device, and the user doesn't want to
105 use an initrd).
106
107 This option is a string and takes the (space-separated) names of the
108 firmware files -- the same names that appear in MODULE_FIRMWARE()
109 and request_firmware() in the source. These files should exist under
110 the directory specified by the EXTRA_FIRMWARE_DIR option, which is
111 /lib/firmware by default.
112
113 For example, you might set CONFIG_EXTRA_FIRMWARE="usb8388.bin", copy
114 the usb8388.bin file into /lib/firmware, and build the kernel. Then
115 any request_firmware("usb8388.bin") will be satisfied internally
116 without needing to call out to userspace.
117
118 WARNING: If you include additional firmware files into your binary
119 kernel image that are not available under the terms of the GPL,
120 then it may be a violation of the GPL to distribute the resulting
121 image since it combines both GPL and non-GPL work. You should
122 consult a lawyer of your own before distributing such an image.
123
124config EXTRA_FIRMWARE_DIR
125 string "Firmware blobs root directory"
126 depends on EXTRA_FIRMWARE != ""
127 default "/lib/firmware"
128 help
129 This option controls the directory in which the kernel build system
130 looks for the firmware files listed in the EXTRA_FIRMWARE option.
131
132config FW_LOADER_USER_HELPER
133 bool
134
135config FW_LOADER_USER_HELPER_FALLBACK
136 bool "Fallback user-helper invocation for firmware loading"
137 depends on FW_LOADER
138 select FW_LOADER_USER_HELPER
139 help
140 This option enables / disables the invocation of user-helper
141 (e.g. udev) for loading firmware files as a fallback after the
142 direct file loading in kernel fails. The user-mode helper is
143 no longer required unless you have a special firmware file that
144 resides in a non-standard path. Moreover, the udev support has
145 been deprecated upstream.
146
147 If you are unsure about this, say N here.
148
149config WANT_DEV_COREDUMP
150 bool
151 help
152 Drivers should "select" this option if they desire to use the
153 device coredump mechanism.
154
155config ALLOW_DEV_COREDUMP
156 bool "Allow device coredump" if EXPERT
157 default y
158 help
159 This option controls if the device coredump mechanism is available or
160 not; if disabled, the mechanism will be omitted even if drivers that
161 can use it are enabled.
162 Say 'N' for more sensitive systems or systems that don't want
163 to ever access the information to not have the code, nor keep any
164 data.
165
166 If unsure, say Y.
167
168config DEV_COREDUMP
169 bool
170 default y if WANT_DEV_COREDUMP
171 depends on ALLOW_DEV_COREDUMP
172
173config DEBUG_DRIVER
174 bool "Driver Core verbose debug messages"
175 depends on DEBUG_KERNEL
176 help
177 Say Y here if you want the Driver core to produce a bunch of
178 debug messages to the system log. Select this if you are having a
179 problem with the driver core and want to see more of what is
180 going on.
181
182 If you are unsure about this, say N here.
183
184config DEBUG_DEVRES
185 bool "Managed device resources verbose debug messages"
186 depends on DEBUG_KERNEL
187 help
188 This option enables kernel parameter devres.log. If set to
189 non-zero, devres debug messages are printed. Select this if
190 you are having a problem with devres or want to debug
191 resource management for a managed device. devres.log can be
192 switched on and off from sysfs node.
193
194 If you are unsure about this, Say N here.
195
196config DEBUG_TEST_DRIVER_REMOVE
197 bool "Test driver remove calls during probe (UNSTABLE)"
198 depends on DEBUG_KERNEL
199 help
200 Say Y here if you want the Driver core to test driver remove functions
201 by calling probe, remove, probe. This tests the remove path without
202 having to unbind the driver or unload the driver module.
203
204 This option is expected to find errors and may render your system
205 unusable. You should say N here unless you are explicitly looking to
206 test this functionality.
207
208source "drivers/base/test/Kconfig"
209
210config SYS_HYPERVISOR
211 bool
212 default n
213
214config GENERIC_CPU_DEVICES
215 bool
216 default n
217
218config GENERIC_CPU_AUTOPROBE
219 bool
220
221config GENERIC_CPU_VULNERABILITIES
222 bool
223
224config SOC_BUS
225 bool
226 select GLOB
227
228source "drivers/base/regmap/Kconfig"
229
230config DMA_SHARED_BUFFER
231 bool
232 default n
233 select ANON_INODES
234 select IRQ_WORK
235 help
236 This option enables the framework for buffer-sharing between
237 multiple drivers. A buffer is associated with a file using driver
238 APIs extension; the file's descriptor can then be passed on to other
239 driver.
240
241config DMA_FENCE_TRACE
242 bool "Enable verbose DMA_FENCE_TRACE messages"
243 depends on DMA_SHARED_BUFFER
244 help
245 Enable the DMA_FENCE_TRACE printks. This will add extra
246 spam to the console log, but will make it easier to diagnose
247 lockup related problems for dma-buffers shared across multiple
248 devices.
249
250config DMA_CMA
251 bool "DMA Contiguous Memory Allocator"
252 depends on HAVE_DMA_CONTIGUOUS && CMA
253 help
254 This enables the Contiguous Memory Allocator which allows drivers
255 to allocate big physically-contiguous blocks of memory for use with
256 hardware components that do not support I/O map nor scatter-gather.
257
258 You can disable CMA by specifying "cma=0" on the kernel's command
259 line.
260
261 For more information see <include/linux/dma-contiguous.h>.
262 If unsure, say "n".
263
264if DMA_CMA
265comment "Default contiguous memory area size:"
266
267config CMA_SIZE_MBYTES
268 int "Size in Mega Bytes"
269 depends on !CMA_SIZE_SEL_PERCENTAGE
270 default 0 if X86
271 default 16
272 help
273 Defines the size (in MiB) of the default memory area for Contiguous
274 Memory Allocator. If the size of 0 is selected, CMA is disabled by
275 default, but it can be enabled by passing cma=size[MG] to the kernel.
276
277
278config CMA_SIZE_PERCENTAGE
279 int "Percentage of total memory"
280 depends on !CMA_SIZE_SEL_MBYTES
281 default 0 if X86
282 default 10
283 help
284 Defines the size of the default memory area for Contiguous Memory
285 Allocator as a percentage of the total memory in the system.
286 If 0 percent is selected, CMA is disabled by default, but it can be
287 enabled by passing cma=size[MG] to the kernel.
288
289choice
290 prompt "Selected region size"
291 default CMA_SIZE_SEL_MBYTES
292
293config CMA_SIZE_SEL_MBYTES
294 bool "Use mega bytes value only"
295
296config CMA_SIZE_SEL_PERCENTAGE
297 bool "Use percentage value only"
298
299config CMA_SIZE_SEL_MIN
300 bool "Use lower value (minimum)"
301
302config CMA_SIZE_SEL_MAX
303 bool "Use higher value (maximum)"
304
305endchoice
306
307config CMA_ALIGNMENT
308 int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
309 range 4 12
310 default 8
311 help
312 DMA mapping framework by default aligns all buffers to the smallest
313 PAGE_SIZE order which is greater than or equal to the requested buffer
314 size. This works well for buffers up to a few hundreds kilobytes, but
315 for larger buffers it just a memory waste. With this parameter you can
316 specify the maximum PAGE_SIZE order for contiguous buffers. Larger
317 buffers will be aligned only to this specified order. The order is
318 expressed as a power of two multiplied by the PAGE_SIZE.
319
320 For example, if your system defaults to 4KiB pages, the order value
321 of 8 means that the buffers will be aligned up to 1MiB only.
322
323 If unsure, leave the default value "8".
324
325endif
326
327config GENERIC_ARCH_TOPOLOGY
328 bool
329 help
330 Enable support for architectures common topology code: e.g., parsing
331 CPU capacity information from DT, usage of such information for
332 appropriate scaling, sysfs interface for changing capacity values at
333 runtime.
334
335endmenu