# SPDX-License-Identifier: GPL-2.0 menu "Generic Driver Options" config AUXILIARY_BUS bool config UEVENT_HELPER bool "Support for uevent helper" help The uevent helper program is forked by the kernel for every uevent. Before the switch to the netlink-based uevent source, this was used to hook hotplug scripts into kernel device events. It usually pointed to a shell script at /sbin/hotplug. This should not be used today, because usual systems create many events at bootup or device discovery in a very short time frame. One forked process per event can create so many processes that it creates a high system load, or on smaller systems it is known to create out-of-memory situations during bootup. config UEVENT_HELPER_PATH string "path to uevent helper" depends on UEVENT_HELPER default "" help To disable user space helper program execution at by default specify an empty string here. This setting can still be altered via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper later at runtime. config DEVTMPFS bool "Maintain a devtmpfs filesystem to mount at /dev" help This creates a tmpfs/ramfs filesystem instance early at bootup. In this filesystem, the kernel driver core maintains device nodes with their default names and permissions for all registered devices with an assigned major/minor number. Userspace can modify the filesystem content as needed, add symlinks, and apply needed permissions. It provides a fully functional /dev directory, where usually udev runs on top, managing permissions and adding meaningful symlinks. In very limited environments, it may provide a sufficient functional /dev without any further help. It also allows simple rescue systems, and reliably handles dynamic major/minor numbers. Notice: if CONFIG_TMPFS isn't enabled, the simpler ramfs file system will be used instead. config DEVTMPFS_MOUNT bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs" depends on DEVTMPFS help This will instruct the kernel to automatically mount the devtmpfs filesystem at /dev, directly after the kernel has mounted the root filesystem. The behavior can be overridden with the commandline parameter: devtmpfs.mount=0|1. This option does not affect initramfs based booting, here the devtmpfs filesystem always needs to be mounted manually after the rootfs is mounted. With this option enabled, it allows to bring up a system in rescue mode with init=/bin/sh, even when the /dev directory on the rootfs is completely empty. config STANDALONE bool "Select only drivers that don't need compile-time external firmware" default y help Select this option if you don't have magic firmware for drivers that need it. If unsure, say Y. config PREVENT_FIRMWARE_BUILD bool "Disable drivers features which enable custom firmware building" default y help Say yes to disable driver features which enable building a custom driver firmware at kernel build time. These drivers do not use the kernel firmware API to load firmware (CONFIG_FW_LOADER), instead they use their own custom loading mechanism. The required firmware is usually shipped with the driver, building the driver firmware should only be needed if you have an updated firmware source. Firmware should not be being built as part of kernel, these days you should always prevent this and say Y here. There are only two old drivers which enable building of its firmware at kernel build time: o CONFIG_WANXL through CONFIG_WANXL_BUILD_FIRMWARE o CONFIG_SCSI_AIC79XX through CONFIG_AIC79XX_BUILD_FIRMWARE source "drivers/base/firmware_loader/Kconfig" config WANT_DEV_COREDUMP bool help Drivers should "select" this option if they desire to use the device coredump mechanism. config ALLOW_DEV_COREDUMP bool "Allow device coredump" if EXPERT default y help This option controls if the device coredump mechanism is available or not; if disabled, the mechanism will be omitted even if drivers that can use it are enabled. Say 'N' for more sensitive systems or systems that don't want to ever access the information to not have the code, nor keep any data. If unsure, say Y. config DEV_COREDUMP bool default y if WANT_DEV_COREDUMP depends on ALLOW_DEV_COREDUMP config DEBUG_DRIVER bool "Driver Core verbose debug messages" depends on DEBUG_KERNEL help Say Y here if you want the Driver core to produce a bunch of debug messages to the system log. Select this if you are having a problem with the driver core and want to see more of what is going on. If you are unsure about this, say N here. config DEBUG_DEVRES bool "Managed device resources verbose debug messages" depends on DEBUG_KERNEL help This option enables kernel parameter devres.log. If set to non-zero, devres debug messages are printed. Select this if you are having a problem with devres or want to debug resource management for a managed device. devres.log can be switched on and off from sysfs node. If you are unsure about this, Say N here. config DEBUG_TEST_DRIVER_REMOVE bool "Test driver remove calls during probe (UNSTABLE)" depends on DEBUG_KERNEL help Say Y here if you want the Driver core to test driver remove functions by calling probe, remove, probe. This tests the remove path without having to unbind the driver or unload the driver module. This option is expected to find errors and may render your system unusable. You should say N here unless you are explicitly looking to test this functionality. config PM_QOS_KUNIT_TEST bool "KUnit Test for PM QoS features" if !KUNIT_ALL_TESTS depends on KUNIT=y default KUNIT_ALL_TESTS config HMEM_REPORTING bool default n depends on NUMA help Enable reporting for heterogeneous memory access attributes under their non-uniform memory nodes. source "drivers/base/test/Kconfig" config SYS_HYPERVISOR bool default n config GENERIC_CPU_DEVICES bool default n config GENERIC_CPU_AUTOPROBE bool config GENERIC_CPU_VULNERABILITIES bool config SOC_BUS bool select GLOB source "drivers/base/regmap/Kconfig" config DMA_SHARED_BUFFER tristate default n select IRQ_WORK help This option enables the framework for buffer-sharing between multiple drivers. A buffer is associated with a file using driver APIs extension; the file's descriptor can then be passed on to other driver. config DMA_FENCE_TRACE bool "Enable verbose DMA_FENCE_TRACE messages" depends on DMA_SHARED_BUFFER help Enable the DMA_FENCE_TRACE printks. This will add extra spam to the console log, but will make it easier to diagnose lockup related problems for dma-buffers shared across multiple devices. config GENERIC_ARCH_TOPOLOGY bool help Enable support for architectures common topology code: e.g., parsing CPU capacity information from DT, usage of such information for appropriate scaling, sysfs interface for reading capacity values at runtime. config GENERIC_ARCH_NUMA bool help Enable support for generic NUMA implementation. Currently, RISC-V and ARM64 use it. endmenu