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 DRIVER_DEFERRED_PROBE_TIMEOUT 77 int "Default value for deferred_probe_timeout" 78 default 0 if !MODULES 79 default 10 if MODULES 80 help 81 Set the default value for the deferred_probe_timeout kernel parameter. 82 See Documentation/admin-guide/kernel-parameters.txt for a description 83 of the deferred_probe_timeout kernel parameter. 84 85config STANDALONE 86 bool "Select only drivers that don't need compile-time external firmware" 87 default y 88 help 89 Select this option if you don't have magic firmware for drivers that 90 need it. 91 92 If unsure, say Y. 93 94config PREVENT_FIRMWARE_BUILD 95 bool "Disable drivers features which enable custom firmware building" 96 default y 97 help 98 Say yes to disable driver features which enable building a custom 99 driver firmware at kernel build time. These drivers do not use the 100 kernel firmware API to load firmware (CONFIG_FW_LOADER), instead they 101 use their own custom loading mechanism. The required firmware is 102 usually shipped with the driver, building the driver firmware 103 should only be needed if you have an updated firmware source. 104 105 Firmware should not be being built as part of kernel, these days 106 you should always prevent this and say Y here. There are only two 107 old drivers which enable building of its firmware at kernel build 108 time: 109 110 o CONFIG_WANXL through CONFIG_WANXL_BUILD_FIRMWARE 111 o CONFIG_SCSI_AIC79XX through CONFIG_AIC79XX_BUILD_FIRMWARE 112 113source "drivers/base/firmware_loader/Kconfig" 114 115config WANT_DEV_COREDUMP 116 bool 117 help 118 Drivers should "select" this option if they desire to use the 119 device coredump mechanism. 120 121config ALLOW_DEV_COREDUMP 122 bool "Allow device coredump" if EXPERT 123 default y 124 help 125 This option controls if the device coredump mechanism is available or 126 not; if disabled, the mechanism will be omitted even if drivers that 127 can use it are enabled. 128 Say 'N' for more sensitive systems or systems that don't want 129 to ever access the information to not have the code, nor keep any 130 data. 131 132 If unsure, say Y. 133 134config DEV_COREDUMP 135 bool 136 default y if WANT_DEV_COREDUMP 137 depends on ALLOW_DEV_COREDUMP 138 139config DEBUG_DRIVER 140 bool "Driver Core verbose debug messages" 141 depends on DEBUG_KERNEL 142 help 143 Say Y here if you want the Driver core to produce a bunch of 144 debug messages to the system log. Select this if you are having a 145 problem with the driver core and want to see more of what is 146 going on. 147 148 If you are unsure about this, say N here. 149 150config DEBUG_DEVRES 151 bool "Managed device resources verbose debug messages" 152 depends on DEBUG_KERNEL 153 help 154 This option enables kernel parameter devres.log. If set to 155 non-zero, devres debug messages are printed. Select this if 156 you are having a problem with devres or want to debug 157 resource management for a managed device. devres.log can be 158 switched on and off from sysfs node. 159 160 If you are unsure about this, Say N here. 161 162config DEBUG_TEST_DRIVER_REMOVE 163 bool "Test driver remove calls during probe (UNSTABLE)" 164 depends on DEBUG_KERNEL 165 help 166 Say Y here if you want the Driver core to test driver remove functions 167 by calling probe, remove, probe. This tests the remove path without 168 having to unbind the driver or unload the driver module. 169 170 This option is expected to find errors and may render your system 171 unusable. You should say N here unless you are explicitly looking to 172 test this functionality. 173 174config PM_QOS_KUNIT_TEST 175 bool "KUnit Test for PM QoS features" if !KUNIT_ALL_TESTS 176 depends on KUNIT=y 177 default KUNIT_ALL_TESTS 178 179config PM_RUNTIME_KUNIT_TEST 180 tristate "KUnit Tests for runtime PM" if !KUNIT_ALL_TESTS 181 depends on KUNIT 182 depends on PM 183 default KUNIT_ALL_TESTS 184 185config HMEM_REPORTING 186 bool 187 default n 188 depends on NUMA 189 help 190 Enable reporting for heterogeneous memory access attributes under 191 their non-uniform memory nodes. 192 193source "drivers/base/test/Kconfig" 194 195config SYS_HYPERVISOR 196 bool 197 default n 198 199config GENERIC_CPU_DEVICES 200 bool 201 default n 202 203config GENERIC_CPU_AUTOPROBE 204 bool 205 206config GENERIC_CPU_VULNERABILITIES 207 bool 208 209config SOC_BUS 210 bool 211 select GLOB 212 213source "drivers/base/regmap/Kconfig" 214 215config DMA_SHARED_BUFFER 216 bool 217 default n 218 select IRQ_WORK 219 help 220 This option enables the framework for buffer-sharing between 221 multiple drivers. A buffer is associated with a file using driver 222 APIs extension; the file's descriptor can then be passed on to other 223 driver. 224 225config DMA_FENCE_TRACE 226 bool "Enable verbose DMA_FENCE_TRACE messages" 227 depends on DMA_SHARED_BUFFER 228 help 229 Enable the DMA_FENCE_TRACE printks. This will add extra 230 spam to the console log, but will make it easier to diagnose 231 lockup related problems for dma-buffers shared across multiple 232 devices. 233 234config GENERIC_ARCH_TOPOLOGY 235 bool 236 help 237 Enable support for architectures common topology code: e.g., parsing 238 CPU capacity information from DT, usage of such information for 239 appropriate scaling, sysfs interface for reading capacity values at 240 runtime. 241 242config GENERIC_ARCH_NUMA 243 bool 244 select NUMA_MEMBLKS 245 help 246 Enable support for generic NUMA implementation. Currently, RISC-V 247 and ARM64 use it. 248 249config FW_DEVLINK_SYNC_STATE_TIMEOUT 250 bool "sync_state() behavior defaults to timeout instead of strict" 251 help 252 This is build time equivalent of adding kernel command line parameter 253 "fw_devlink.sync_state=timeout". Give up waiting on consumers and 254 call sync_state() on any devices that haven't yet received their 255 sync_state() calls after deferred_probe_timeout has expired or by 256 late_initcall() if !CONFIG_MODULES. You should almost always want to 257 select N here unless you have already successfully tested with the 258 command line option on every system/board your kernel is expected to 259 work on. 260 261endmenu 262