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