Lines Matching +full:can +full:- +full:disable
5 force -- enable ACPI if default was off
6 on -- enable ACPI but allow fallback to DT [arm64]
7 off -- disable ACPI if default was on
8 noirq -- do not use ACPI for IRQ routing
9 strict -- Be less tolerant of platforms that are not
11 rsdt -- prefer RSDT over (default) XSDT
12 copy_dsdt -- copy DSDT to memory
26 If set to vendor, prefer vendor-specific driver
31 If set to none, disable the ACPI backlight interface.
40 Disable AML predefined validation mechanism
41 This mechanism can repair the evaluation result to make
58 Documentation/firmware-guide/acpi/debug.rst for more information about
81 can interfere with legacy drivers.
113 by unsupported hardware/firmware features can result in
116 This facility can be used to prevent such uncontrolled
121 Disable auto-serialization of AML methods
124 auto-serialization feature.
128 acpi_no_memhotplug [ACPI] Disable memory hotplug. Useful for kdump
132 Disable installation of static SSDTs at early boot time
142 Ignore the ACPI-based watchdog interface (WDAT) and let
163 acpi_osi=! # disable all built-in OS vendor
165 acpi_osi=!! # enable all built-in OS vendor
167 acpi_osi= # disable all strings
169 'acpi_osi=!' can be used in combination with single or
171 vendor string(s). Note that such command can only
182 can make '_OSI("Windows 2000")' TRUE.
186 exist in the ACPI namespace. NOTE that such command can
191 1. 'acpi_osi=' can make 'CondRefOf(_OSI, Local1)'
194 'acpi_osi=!*' can be used in combination with single or
196 string(s). Note that such command can affect the
206 1. 'acpi_osi="Module Device" acpi_osi=!*' can make
208 2. 'acpi_osi=!* acpi_osi="Module Device"' can make
227 For broken nForce2 BIOS resulting in XT-PIC timer.
235 as soon as the kernel's real-mode entry point is called.
260 off: disable AGP support
265 See Documentation/sound/alsa-configuration.rst
272 align_va_addr= [X86-64]
277 CPU-intensive style benchmark, and it can vary highly in
280 32: only for 32-bit processes
281 64: only for 64-bit processes
282 on: enable for both 32- and 64-bit processes
283 off: disable for both 32- and 64-bit processes
292 amd_iommu= [HW,X86-64]
295 fullflush - enable flushing of IO/TLB entries when
299 off - do not initialize any AMD IOMMU found in
301 force_isolation - Force device isolation for all
307 amd_iommu_dump= [HW,X86-64]
313 amd_iommu_intr= [HW,X86-64]
316 legacy - Use legacy interrupt remapping mode.
317 vapic - Use virtual APIC mode, which allows IOMMU
319 This mode requires kvm-amd.avic=1.
333 Power management functions (SPARCstation-4/5 + deriv.)
335 Disable APC CPU standby support. SPARCstation-Fox does
336 not play well with APC CPU idle - disable it if you have
343 when initialising the APIC and IO-APIC components.
344 For X86-32, this can also be used to specify an APIC
364 to set it to "all" by meaning -- no limit here.
373 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
397 audit= [KNL] Enable the audit sub-system
399 0 | off - kernel audit is disabled and can not be
401 unset - kernel audit is initialized but disabled and
403 1 | on - kernel audit is initialized and partially
414 behavior is to disable the BAU (i.e. bau=0).
416 0 - Disable the BAU.
417 1 - Enable the BAU.
418 unset - Disable the BAU.
439 See Documentation/block/cmdline-partition.rst
447 Extended command line options can be added to an initrd
450 See Documentation/admin-guide/bootconfig.rst
453 Disable BERT OS support on buggy BIOSes.
456 Disable BGRT to avoid flickering OEM logo.
461 bttv.pll= See Documentation/admin-guide/media/bttv.rst
470 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
489 inclusive. See arch/mips/include/asm/pgtable-bits.h
496 cgroup_disable= [KNL] Disable a particular controller
497 Format: {name of the controller(s) to disable}
499 - foo isn't auto-mounted if you mount all cgroups in
501 - foo isn't visible as an individually mountable
504 cut the overhead, others just disable the usage. So
507 cgroup_no_v1= [KNL] Disable cgroup controllers and named hierarchies in v1
518 nosocket -- Disable socket memory accounting.
519 nokmem -- Disable kernel memory accounting.
520 kmem -- Enable kernel memory accounting.
525 0 -- check protection applied by kernel (includes
527 1 -- check protection requested by application.
529 Value can be changed at runtime via
541 force such clocks to be always-on nor does it reserve
545 information, see Documentation/driver-api/clk.rst.
547 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
564 [X86-32] pit,hpet,tsc;
571 [X86-64] hpet,tsc
576 Enable/disable the eventstream feature of the ARM
577 architected timer so that code using WFE-based polling
578 loops can be debugged more effectively on production
588 Disable CPUID feature X for the kernel. See
597 Also note the kernel might malfunction if you disable
600 cma=nn[MG]@[start[MG][-end[MG]]]
611 Sets the size of kernel per-numa memory area for
613 per-numa CMA altogether. And If this option is not
615 With per-numa CMA enabled, DMA users on node nid will
631 com20020= [HW,NET] ARCnet - COM20020 chipset
635 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
639 ARCnet - COM90xx chipset (memory-mapped buffers)
657 See Documentation/admin-guide/serial-console.rst for more
667 Start an early, polled-mode console on the 8250/16550
670 MMIO inter-register address stride is either 8-bit
671 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
675 the h/w is not re-initialized.
696 syscall, or to executing "dmesg -S --raw" or to reading
711 Enable/disable the CPU sampling based debugging.
712 0: default value, disable debugging
716 disable the cpuidle sub-system
722 disable the cpufreq sub-system
730 [X86] Delay for N microsec between assert and de-assert
740 [KNL] Using kexec, Linux can switch to a 'crash kernel'
745 [KNL, X86-64] Select a region under 4G first, and
748 See Documentation/admin-guide/kdump/kdump.rst for further details.
753 start-[end] where start and end are both
755 Documentation/admin-guide/kdump/kdump.rst for an example.
758 [KNL, X86-64] range could be above 4G. Allow kernel
765 [KNL, X86-64] range under 4G. When crashkernel=X,high
770 low memory is needed to make sure DMA buffers for 32-bit
775 0: to disable low allocation.
780 [KNL] Disable crypto self-tests
794 See also Documentation/input/devices/joystick-parport.rst
798 Documentation/admin-guide/dynamic-debug-howto.rst for
812 [KNL] verbose self-tests
815 self-tests.
817 1 will print _a lot_ more information - normally
823 [KNL] Disable object debugging
855 Format: { on, no-mount, off }
857 no-mount:
858 Filesystem is not registered but kernel clients can
859 access APIs and a crashkernel can be used to read
862 get a -EPERM as result when trying to register files
866 Default value is set in build-time with a kernel configuration.
882 Documentation/admin-guide/mm/hugetlbpage.rst.
912 can be useful when debugging issues that require an SLB
920 disable= [IPV6]
929 against bounds-checking flaws in the kernel's
932 off Disable hardened usercopy checks.
935 Disable RADIX MMU mode on POWER9
938 Disable RADIX GTSE feature and use hcall for TLB
942 Disable TLBIE instruction. Currently does not work
950 disable BSP to wake up multiple CPUs without
956 Disable Intel PMU counter freezing feature.
961 Disable Dynamic DMA Window support. Use this
979 Disable PIN 1 of APIC timer
980 Can be useful to work around chipset bugs.
982 dis_ucode_ldr [X86] Disable the microcode loader.
989 entries for DMA-API debugging code. One entry is
990 required per DMA-API allocation. Use this if the
991 DMA-API debugging code disables itself because the
995 With this option the DMA-API debugging driver
996 filter feature can be enabled at boot time. Just
998 The filter can be disabled or changed to another
1010 Generic built-in EDID data sets are used, if one of
1015 available in Documentation/admin-guide/edid.rst. An EDID
1027 Control how the dt_cpu_ftrs device-tree binding is
1037 what data is available or for reverse-engineering.
1042 Documentation/admin-guide/dynamic-debug-howto.rst
1045 nopku [X86] Disable Memory Protection Keys CPU feature found
1059 determined by stdout-path property in device tree's
1064 Start an early, polled-mode console on a Cadence
1075 Start an early, polled-mode console on the 8250/16550
1077 MMIO inter-register address stride is either 8-bit
1078 (mmio) or 32-bit (mmio32 or mmio32be).
1086 Start an early, polled-mode console on a pl011 serial
1090 the driver will use only 32-bit accessors to read/write
1094 Start an early, polled-mode console on a meson serial
1100 Start an early, polled-mode console on an msm serial
1106 Start an early, polled-mode console on an msm serial
1112 Start an early, polled-mode console on a serial port
1118 Start an early, polled-mode console on a serial port
1124 Use RISC-V SBI (Supervisor Binary Interface) for early
1142 Start an early, polled-mode console on a lantiq serial
1156 Start an early, polled-mode, output-only console on the
1161 Start an early, polled-mode console on the
1167 Start an early, polled-mode console on a Qualcomm
1175 coherent non-x86 systems that use system memory for
1200 Append ",keep" to not disable it when the real console
1203 Only one of vga, efi, serial, or usb debug port can
1211 You can find the port for a given device in
1221 The xen output can only be used by Xen PV guests.
1223 The sclp output can only be used on s390.
1233 off: disable H/W event reporting through EDAC.
1244 but can only be used if the backing tty is available
1256 disable_early_pci_dma: disable the busmaster bit on all
1258 nochunk: disable reading files in "chunks" in the EFI
1259 boot stub, as chunking can cause problems with some
1261 noruntime : disable EFI runtime services support
1265 claim. Specify efi=nosoftreserve to disable this
1273 Using this parameter you can use more than 50% of
1286 attribute is added to range 0x100000000-0x180000000 and
1287 0x10a0000000-0x1120000000.
1291 range 0x240000000-0x43fffffff.
1293 Using this parameter you can do debugging of EFI memmap
1294 related features. For example, you can do debugging of
1303 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1309 elanfreq= [X86-32]
1317 See Documentation/admin-guide/kdump/kdump.rst for details.
1326 Can be useful to work around chipset bugs
1333 0 -- permissive (log only, no denials).
1334 1 -- enforcing (deny and log).
1336 Value can be changed at runtime via
1340 Disable Error Record Serialization Table (ERST)
1358 See also Documentation/fault-injection/.
1362 See Documentation/admin-guide/sysctl/net.rst for
1366 See Documentation/admin-guide/blockdev/floppy.rst.
1369 [IA-64] Avoid check_sal_cache_flush which may hang on
1374 forcepae [X86-32]
1376 Many Pentium M systems disable PAE but may have a
1393 ftrace_filter=[function-list]
1395 tracer at boot up. function-list is a comma separated
1396 list of functions. This list can be changed at run
1400 ftrace_notrace=[function-list]
1402 function-list. This list can be changed at run time
1406 ftrace_graph_filter=[function-list]
1409 function-list is a comma separated list of functions
1410 that can be changed at run time by the
1413 ftrace_graph_notrace=[function-list]
1415 function-list. This list is a comma separated list of
1416 functions that can be changed at run time by the
1422 can be changed at run time by the max_graph_depth file
1435 off -- Don't create device links from firmware info.
1436 permissive -- Create device links from firmware info
1439 on -- Create device links from firmware info and use it
1441 rpm -- Like "on", but also use to order runtime PM.
1447 See also Documentation/input/devices/joystick-parport.rst
1451 gart_fix_e820= [X86-64] disable the fix e820 for K8 GART
1455 gcov_persist= [GCOV] When non-zero (default), profiling data for
1488 gpio-mockup.gpio_mockup_ranges
1493 [KNL] Should the hard-lockup detector generate
1499 for 64-bit NUMA, off otherwise.
1502 hcl= [IA-64] SGI's Hardware Graph compatibility layer
1508 Disable Hardware Error Source Table (HEST) support;
1509 corresponding firmware-first mode error processing
1517 highres= [KNL] Enable/disable high resolution timer mode.
1523 hpet= [X86-32,HPET] option to control HPET usage
1524 Format: { enable (default) | disable | force |
1526 disable: disable HPET and use PIT instead
1540 boot-time allocation of gigantic hugepages is skipped.
1548 Documentation/admin-guide/mm/hugetlbpage.rst.
1555 hugepagesz=X hugepages=Y can be specified once for
1558 Documentation/admin-guide/mm/hugetlbpage.rst.
1567 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1568 option. The value selected by this boot parameter can
1573 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1596 (disabled by default, and as a pre-condition
1598 i8042.direct [HW] Put keyboard port into non-translated mode
1599 i8042.dumbkbd [HW] Pretend that controller can only read data from
1604 i8042.noloop [HW] Disable the AUX Loopback command while probing
1612 suspend-to-ram transitions, only during s2r
1647 -1 -- never invert brightness
1648 0 -- machine default
1649 1 -- force brightness inversion
1654 ide-core.nodma= [HW] (E)IDE subsystem
1660 ide-generic.probe-mask= [HW] (E)IDE subsystem
1672 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
1677 Poll forces a polling idle loop that can slightly
1683 idle=nomwait: Disable mwait for CPU C-states
1700 legacy only accept legacy-NaN binaries, if supported
1702 2008 only accept 2008-NaN binaries, if supported
1711 'relaxed' straps the emulator for both legacy-NaN and
1712 2008-NaN, whereas 'strict' enables legacy-NaN only on
1721 Ignore loglevel setting - this will print /all/
1729 print warning at first misuse. Can be changed via
1785 Formats: { "ima" | "ima-ng" | "ima-sig" }
1786 Default: "ima-ng"
1798 different crypto accelerators. This option can be used
1806 different crypto accelerators. This option can be used
1818 initcall_blacklist= [KNL] Do not execute a comma-separated list of
1819 initcall functions. Useful for debugging built-in
1842 default (disallow access to all but pkey 0). Can
1852 0 -- basic integrity auditing messages. (Default)
1853 1 -- additional integrity auditing messages.
1859 Disable intel iommu driver.
1866 forcedac [X86-64]
1868 for io virtual address below 32-bit forcing dual
1870 than 32-bit addressing. The default is to look
1871 for translation below 32-bit and if not available
1889 could harm performance of some high-throughput
1896 Disable bounce buffer for untrusted devices such as
1903 1 to 9 specify maximum depth of C-state.
1906 disable
1913 used along with the hardware-managed P-states (HWP)
1917 in favor of acpi-cpufreq. Forcing the intel_pstate driver
1918 instead of acpi-cpufreq may disable platform features, such
1920 P-States information being indicated to OSPM and therefore
1923 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
1936 Allow per-logical-CPU P-State performance control limits using
1939 intremap= [X86-64, Intel-IOMMU]
1941 off disable Interrupt Remapping
1942 nosid disable Source ID checking
1944 BIOS x2APIC opt-out request will be ignored
1945 nopost disable Interrupt Posting
1947 iomem= Disable strict checking of access to MMIO memory
1964 Disable IOMMU bypass, using IOMMU for PCI devices.
1968 0 - Lazy mode.
1974 1 - Strict mode (default).
1981 0 - Use IOMMU translation for DMA.
1982 1 - Bypass the IOMMU for DMA.
1983 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
1985 io7= [HW] IO7 for Marvel-based Alpha systems
2000 See Documentation/admin-guide/nfs/nfsroot.rst.
2024 Enables support for pseudo-NMIs in the kernel. This
2043 [Deprecated - use cpusets instead]
2044 Format: [flag-list,]<cpu-list>
2050 Disable the tick when a single task runs.
2067 advised to use cpusets instead to disable scheduler load
2069 It offers a much more flexible interface where CPUs can
2072 You can move a process onto or off an "isolated" CPU via
2075 "number of CPUs in system - 1".
2101 The format of <cpu-list> is described above.
2105 ivrs_ioapic [HW,X86-64]
2106 Provide an override to the IOAPIC-ID<->DEVICE-ID
2108 By default, PCI segment is 0, and can be omitted.
2110 For example, to map IOAPIC-ID decimal 10 to
2116 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2119 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2123 ivrs_hpet [HW,X86-64]
2124 Provide an override to the HPET-ID<->DEVICE-ID
2126 By default, PCI segment is 0, and can be omitted.
2128 For example, to map HPET-ID decimal 10 to
2134 * To map HPET-ID decimal 0 to PCI device 00:14.0
2137 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2141 ivrs_acpihid [HW,X86-64]
2142 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2144 By default, PCI segment is 0, and can be omitted.
2146 For example, to map UART-HID:UID AMD0020:0 to
2152 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2155 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2175 kernelcore= [KNL,X86,IA-64,PPC]
2178 the kernel for non-movable allocations. The requested
2188 subsystem. Note that allocations like PTEs-from-HighMem
2196 for non-movable allocations and remaining memory is used
2207 gdb or control-c on the dbgp connection. When
2208 not using this parameter you use sysrq-g to break into
2213 or a supported polling keyboard driver (non-usb).
2223 characters and can work in polling mode, you can use
2240 Configure the RouterBoard 532 series on-chip
2243 kmemleak= [KNL] Boot-time kmemleak enable/disable
2249 kprobe_event=[probe-list]
2251 The probe-list is a semicolon delimited list of probe
2297 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
2300 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
2302 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
2304 kvm-arm.vgic_v3_group0_trap=
2305 [KVM,ARM] Trap guest accesses to GICv3 group-0
2308 kvm-arm.vgic_v3_group1_trap=
2309 [KVM,ARM] Trap guest accesses to GICv3 group-1
2312 kvm-arm.vgic_v3_common_trap=
2316 kvm-arm.vgic_v4_enable=
2328 kvm-intel.ept= [KVM,Intel] Disable extended page tables
2332 kvm-intel.emulate_invalid_guest_state=
2333 [KVM,Intel] Disable emulation of invalid guest state.
2334 Ignored if kvm-intel.enable_unrestricted_guest=1, as
2340 kvm-intel.flexpriority=
2341 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
2344 kvm-intel.nested=
2348 kvm-intel.unrestricted_guest=
2349 [KVM,Intel] Disable unrestricted guest feature
2353 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2354 CVE-2018-3620.
2360 VMEXIT and VMENTER can leak host memory.
2365 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
2432 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
2438 lapic [X86-32,APIC] Enable the local APIC even if BIOS
2442 value for LAPIC timer one-shot implementation. Default
2450 libata.dma=0 Disable all PATA and SATA DMA
2477 first fan-out link behind PMP device. It does not
2484 The following configurations can be forced.
2491 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
2503 hot-unplug link recovery
2509 * disable: Disable this device.
2540 Set the number of locking read-acquisition kthreads.
2545 Set the number of locking write-acquisition kthreads.
2548 Set time (s) after boot for CPU-hotplug testing.
2551 Set time (s) between CPU-hotplug operations, or
2552 zero to disable CPU-hotplug testing.
2555 Set task-shuffle interval (jiffies). Shuffling
2556 tasks allows some CPUs to go into dyntick-idle
2561 is useful for hands-off automated testing.
2583 console loglevel will be printed to the console. It can
2594 7 (KERN_DEBUG) debug-level messages
2604 logo.nologo [FB] Disables display of the built-in Linux logo.
2612 lp=auto printer driver. 'lp=reset' (which can be
2622 an IEEE 1284-compliant printer is attached; if
2628 time-consuming boot-time autodetection (up to 250 ms per
2649 machvec= [IA-64] Force the use of a particular machine-vector
2655 Example: machtype=lemote-yeeloong-2f-7inch
2663 bootup you can bring up the other plugged cpu by executing
2670 (loop.max_loop) unconditionally pre-created at init time. The default
2673 devices can be requested on-demand with the
2674 /dev/loop-control interface.
2676 mce [X86-32] Machine Check Exception
2678 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.rst
2681 See Documentation/admin-guide/md.rst.
2688 Control mitigation for the Micro-architectural Data
2692 internal buffers which can forward information to a
2696 forwarded data can be used in a cache side channel
2703 full - Enable MDS mitigation on vulnerable CPUs
2704 full,nosmt - Enable MDS mitigation and disable
2706 off - Unconditionally disable MDS mitigation
2708 On TAA-affected machines, mds=off can be prevented by
2710 mitigated with the same mechanism so in order to disable
2717 For details see: Documentation/admin-guide/hw-vuln/mds.rst
2736 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
2741 per-device physically contiguous DMA buffers.
2749 See Documentation/admin-guide/mm/memory-hotplug.rst.
2753 Such memmap=exactmap lines can be constructed based on
2762 Multiple different regions can be specified,
2774 Example: Exclude memory from 0x18690000-0x1869ffff
2788 memmap=<size>%<offset>-<oldtype>+<newtype>
2790 from <oldtype> to <newtype>. If "-<oldtype>" is left
2805 repeatable BIOS-originated corruption always
2806 affects the same memory, you can use memmap=
2822 default : 0 <disable>
2830 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
2838 Refer to Documentation/virt/kvm/amd-memory-encryption.rst
2839 for details on when memory encryption can be activated.
2842 s2idle - Suspend-To-Idle
2843 shallow - Power-On Suspend or equivalent (if supported)
2844 deep - Suspend-To-RAM or equivalent (if supported)
2845 See Documentation/admin-guide/pm/sleep-states.rst.
2848 See Documentation/admin-guide/media/meye.rst.
2850 mfgpt_irq= [IA-32] Specify the IRQ to use for the
2851 Multi-Function General Purpose Timers on AMD Geode
2854 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
2857 problem by letting the user disable the workaround.
2868 0 - The attached screen is the 3.5" TFT
2869 1 - The attached screen is the 7" TFT
2870 2 - The VGA Shield is attached (1024x768)
2874 b - Enable backlight. The TFT backlight pin will be
2878 c - Enable the s3c camera interface.
2879 t - Reserved for enabling touchscreen support. The
2881 kernel as of 2.6.30, a preliminary port can be found
2883 https://repo.or.cz/w/linux-2.6/mini2440.git
2888 arch-independent options, each of which is an
2889 aggregation of existing arch-specific options.
2892 Disable all optional CPU mitigations. This
2902 ssbd=force-off [ARM64]
2922 have other ways of avoiding SMT-based attacks.
2957 full - Enable mitigation on vulnerable CPUs
2959 full,nosmt - Enable mitigation and disable SMT on
2962 off - Unconditionally disable mitigation
2965 mmio_stale_data=off can be prevented by an active
2968 disable this mitigation, you need to specify
2975 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
2983 module_blacklist= [KNL] Do not load a comma-separated list of
2997 movablecore= [KNL,X86,IA-64,PPC]
3008 movable_node [KNL] Boot-time switch to make hotplugable memory
3015 Format: <name>,<region-number>,<size>,<offset>
3018 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3027 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
3031 boundary - index of last SLC block on Flex-OneNAND.
3033 lock - Configure if Flex-OneNAND boundary should be locked.
3040 See arch/arm/mach-s3c2412/mach-jive.c
3068 something different and driver-specific.
3074 0 to disable accounting
3079 See Documentation/admin-guide/nfs/nfsroot.rst.
3081 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3082 See Documentation/admin-guide/nfs/nfsroot.rst.
3085 See Documentation/admin-guide/nfs/nfsroot.rst.
3109 [NFS] enable 64-bit inode numbers.
3110 If zero, the NFS client will fake up a 32-bit inode
3112 of returning the full 64-bit number.
3113 The default is to return 64-bit inode numbers.
3126 that the client can send to the NFSv4.1 server.
3136 disabling idmapping, which can make migration from
3143 [NFS4] Specify an additional fixed unique ident-
3144 ification string that NFSv4 clients can insert into
3174 driver. A non-zero value sets the minimum interval
3186 NMI stack-backtrace request.
3195 0 - turn hardlockup detector in nmi_watchdog off
3196 1 - turn hardlockup detector in nmi_watchdog on
3200 To disable both hard and soft lockup detectors,
3205 These settings can be accessed at runtime via
3213 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
3217 no5lvl [X86-64] Disable 5-level paging mode. Forces
3218 kernel to use 4-level paging instead.
3224 Disable suspending of consoles during suspend and
3226 messages can reach various consoles while the rest
3238 Disable device dump. Device dump allows drivers to
3239 append dump data to vmcore so you can collect driver
3240 specified debug info. Drivers can append the data
3243 device dump can help save memory but the driver debug
3249 caches in the slab allocator. Saves per-node memory,
3260 noautogroup Disable scheduler automatic task group creation.
3269 nodelayacct [KNL] Disable per-task delay accounting
3271 nodsp [SH] Disable hardware DSP at boot time.
3273 noefi Disable EFI runtime services support.
3275 no_entry_flush [PPC] Don't flush the L1-D cache when entering the kernel.
3277 noexec [IA-64]
3280 On X86-32 available only on PAE configured kernels.
3281 noexec=on: enable non-executable mappings (default)
3282 noexec=off: disable non-executable mappings
3285 Disable SMAP (Supervisor Mode Access Prevention)
3289 Disable SMEP (Supervisor Mode Execution Prevention)
3292 noexec32 [X86-64]
3293 This affects only 32-bit executables.
3294 noexec32=on: enable non-executable mappings (default)
3296 noexec32=off: disable non-executable mappings
3299 nofpu [MIPS,SH] Disable hardware FPU at boot time.
3301 nofxsr [BUGS=X86-32] Disables x86 floating point extended
3303 legacy floating-point registers on task switch.
3305 nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
3307 nosmt [KNL,S390] Disable symmetric multithreading (SMT).
3310 [KNL,X86] Disable symmetric multithreading (SMT).
3311 nosmt=force: Force disable SMT, cannot be undone
3314 nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1
3318 nospectre_v2 [X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for
3324 [HW] Disable all mitigations for the Speculative Store Bypass vulnerability
3327 [PPC] Don't flush the L1-D cache after accessing user data.
3331 enabling legacy floating-point and sse state.
3356 nohalt [IA-64] Tells the kernel not to use the power saving
3358 power-consumption. On the positive side, it reduces
3359 interrupt wake-up latency, which may improve performance
3361 real-time systems.
3363 nohibernate [HIBERNATION] Disable hibernation and resume.
3365 nohz= [KNL] Boottime enable/disable dynamic ticks
3381 noirqdebug [X86-32] Disables the code which attempts to detect and
3382 disable unhandled interrupt sources.
3392 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
3394 [Deprecated - use intremap=off]
3396 nointroute [IA-64]
3398 noinvpcid [X86] Disable the INVPCID cpu feature.
3400 nojitter [IA-64] Disables jitter checking for ITC timers.
3402 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
3404 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
3407 no-vmw-sched-clock
3408 [X86,PV_OPS] Disable paravirtualized VMware scheduler
3411 no-steal-acc [X86,PV_OPS,ARM64] Disable paravirtualized steal time
3415 nolapic [X86-32,APIC] Do not enable or use the local APIC.
3417 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
3422 nomca [IA-64] Disable machine check abort handling
3424 nomce [X86-32] Disable Machine Check Exception
3426 nomfgpt [X86-32] Disable Multi-Function General Purpose
3429 nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to
3433 nomodule Disable module load
3435 nopat [X86] Disable PAT (page attribute table extension of
3438 nopcid [X86-64] Disable the PCID cpu feature.
3443 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
3446 nordrand [X86] Disable kernel use of the RDRAND and
3454 no-scroll [VGA] Disables scrollback.
3455 This is required for the Braillex ib80-piezo Braille
3458 nosbagart [IA-64]
3460 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
3463 and disable the IO APIC. legacy for "maxcpus=0".
3465 nosoftlockup [KNL] Disable the soft-lockup detector.
3469 nowatchdog [KNL] Disable both lockup detectors, i.e.
3470 soft-lockup and NMI watchdog (hard-lockup).
3474 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
3482 2. PIC interrupts also depend on CPU0. CPU0 can't be
3487 If the dependencies are under your control, you can
3492 cycles, each HW thread of the CTOP can run
3499 nptcg= [IA-64] Override max number of concurrent global TLB
3507 runtime you can physically add extra cpu until it reaches
3508 n. So during boot up some boot time memory for per-cpu
3509 variables need be pre-allocated for later physical cpu
3514 numa_balancing= [KNL,X86] Enable or disable automatic NUMA balancing.
3515 Allowed values are enable and disable
3518 'node', 'default' can be specified
3519 This can be set from sysctl after boot.
3520 See Documentation/admin-guide/sysctl/vm.rst for details.
3523 See Documentation/core-api/debugging-via-ohci1394.rst for more
3562 running on a platform with a direct-mapped memory-side
3563 cache, and this parameter can be used to
3564 override/disable that behavior. The state of the flag
3565 can be read from sysfs at:
3568 page_owner= [KNL] Boot-time page_owner enabling option.
3571 we can turn it on.
3574 page_poison= [KNL] Boot-time parameter changing the state of
3587 User can chose combination of the following bits:
3600 The optional switch "nousertaint" can be utilized to
3604 See Documentation/admin-guide/tainted-kernels.rst for
3605 extra details on the taint flags that users can pick
3612 Run kdump after running panic-notifiers and dumping
3616 because some panic notifiers can make the crashed
3631 possible conflicts). You can specify the base
3657 See also Documentation/admin-guide/blockdev/paride.rst.
3676 addresses can be specified after the base
3686 bios [X86-32] force use of PCI BIOS, don't access
3688 has a non-standard PCI host bridge.
3689 nobios [X86-32] disallow use of PCI BIOS, only direct
3695 data in IO port 0xCFC, both 32-bit).
3697 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
3698 the function, IO port 0xCFA, also 8-bit, sets
3700 through ports 0xC000-0xCFFF).
3704 enabled, this kernel boot option can be used to
3705 disable the use of PCIE advanced error reporting.
3706 nodomains [PCI] Disable support for multiple PCI
3707 root domains (aka PCI segments, in ACPI-speak).
3708 nommconf [X86] Disable use of MMCONFIG for PCI
3714 enabled, this kernel boot option can be used to
3715 disable the use of MSI interrupts system-wide.
3716 noioapicquirk [APIC] Disable all boot interrupt quirks.
3720 primary IO-APIC for bridges that cannot disable
3723 noioapicreroute [APIC] Disable workaround that uses the
3727 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
3745 assigned automatically to PCI devices. You can
3751 F0000h-100000h range.
3752 lastbus=N [X86] Scan all buses thru bus #N. Can be
3756 assign-busses [X86] Always assign all PCI bus
3777 skip_isa_align [X86] do not align io start addr, so can
3784 bfsort Sort PCI devices into breadth-first order.
3787 nobfsort Don't sort PCI devices into breadth-first order.
3788 pcie_bus_tune_off Disable PCIe MPS (Max Payload Size)
3789 tuning and use the BIOS-configured MPS defaults.
3796 or bus can support) for best performance.
3799 configuration allows peer-to-peer DMA between
3802 that hot-added devices will work.
3817 A PCI-PCI bridge can be specified if resource
3823 for 4096-byte alignment.
3824 ecrc= Enable/disable PCIe ECRC (transaction layer
3825 end-to-end CRC checking).
3846 realloc= Enable/disable reallocating PCI bridge resources
3854 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
3861 can resize a BAR to allow access to all VRAM.
3879 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
3881 off Disable ASPM.
3890 dpc-native Use native PCIe service for DPC only. May
3892 compat Disable native PCIe services (PME, AER, DPC, PCIe
3896 off Disable power management of all PCIe ports
3907 Keep all power-domains already enabled by bootloader on,
3913 See Documentation/admin-guide/blockdev/paride.rst.
3915 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
3928 See Documentation/admin-guide/blockdev/paride.rst.
3931 See Documentation/admin-guide/blockdev/paride.rst.
3933 pirq= [SMP,APIC] Manual mp-table setup
3934 See Documentation/x86/i386/IO-APIC.rst.
3938 See also Documentation/admin-guide/parport.rst.
3949 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
3958 { on | off | curr | res | no-curr | no-res }
3994 Disable Hardware Transactional Memory
3996 print-fatal-signals=
4002 coredump - etc.
4005 you might want to try "ulimit -i unlimited".
4012 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
4017 on - unlimited logging to /dev/kmsg from userspace
4018 off - logging to /dev/kmsg disabled
4019 ratelimit - ratelimit the logging
4023 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
4026 Limit processor to maximum C-state
4030 Ignore the _CST method to determine C-states,
4037 Param: "schedule" - profile schedule points.
4038 Param: "sleep" - profile D-state sleeping (millisecs).
4040 Param: "kvm" - profile VM exits.
4041 Param: <number> - step/bucket size as a power of 2 for
4051 psi= [KNL] Enable or disable pressure stall information
4071 See Documentation/admin-guide/blockdev/paride.rst.
4073 pti= [X86-64] Control Page Table Isolation of user and
4078 on - unconditionally enable
4079 off - unconditionally disable
4080 auto - kernel detects whether your CPU model is
4085 nopti [X86-64]
4089 [KNL] Number of legacy pty's. Overwrites compiled-in
4092 quiet [KNL] Disable most log messages
4097 See Documentation/admin-guide/md.rst.
4100 See Documentation/admin-guide/blockdev/ramdisk.rst.
4105 [KNL] Enable or disable trusting the use of the
4111 [KNL] Enable or disable trusting the use of a
4116 ras=option[,option,...] [KNL] RAS-specific options
4119 Disable the Correctable Errors Collector,
4124 except that the string "all" can be used to
4128 the specified list of CPUs to be no-callback CPUs.
4131 purpose, where "x" is "p" for RCU-preempt, and
4132 "s" for RCU-sched, and "N" is the CPU number.
4134 which can be useful for HPC and real-time
4135 workloads. It can also improve energy efficiency
4143 This improves the real-time response for the
4160 RCU grace-period cleanup.
4164 RCU grace-period initialization.
4168 RCU grace-period pre-initialization, that is,
4169 the propagation of recent CPU-hotplug changes up
4174 per-CPU rcuc kthreads. Defaults to a non-zero
4179 Disable autobalancing of the rcu_node combining
4182 cache-to-cache transfer latencies.
4188 and for NUMA systems with large remote-access
4201 Set delay from grace-period initialization to
4214 soliciting quiescent-state help from
4226 Set the SCHED_FIFO priority of the RCU per-CPU
4229 and for the RCU grace-period kthreads (rcu_bh,
4231 set, valid values are 1-99 and the default is 1
4232 (the least-favored priority). Otherwise, when
4233 RCU_BOOST is not set, valid values are 0-99 and
4234 the default is zero (non-realtime operation).
4240 the wakeup overhead on the global grace-period
4242 each group's NOCB grace-period kthread.
4250 batch limiting is re-enabled.
4254 RCU's force-quiescent-state scan will aggressively
4259 disable more aggressive help enlistment.
4268 Lazy RCU callbacks are those which RCU can
4272 Cause the grace-period kthread to get an extra
4274 it should at force-quiescent-state time.
4280 this specifies an rcu_read_unlock()-time delay
4284 of RCU-protected pointers after the relevant
4294 grace-period primitives such as call_rcu().
4305 grace-period primitives.
4308 Set test-start holdoff period. The purpose of
4327 Set number of RCU readers. The value -1 selects
4329 "n" less than -1 selects N-n+1, where N is again
4330 the number of CPUs. For example, -2 selects N
4331 (the number of CPUs), -3 selects N+1, and so on.
4332 A value of "n" less than or equal to -N selects
4345 complete. This is useful for hands-off automated
4352 Write-side holdoff between grace periods,
4369 Enable RCU grace-period forward-progress testing
4373 Specify the fraction of a CPU-stall-warning
4374 period to do tight-loop forward-progress testing.
4378 forward-progress tests.
4382 need_resched() during tight-loop forward-progress
4386 Use conditional/asynchronous update-side
4390 Use expedited update-side primitives, if available.
4393 Use normal (non-expedited) asynchronous
4394 update-side primitives, if available.
4397 Use normal (non-expedited) synchronous
4398 update-side primitives, if available. If all
4402 they are all non-zero.
4410 Leak an RCU-protected pointer out of the reader.
4411 This can of course result in splats, and is
4425 Set number of RCU readers. The value -1 selects
4426 N-1, where N is the number of CPUs. A value
4427 "n" less than -1 selects N-n-2, where N is again
4428 the number of CPUs. For example, -2 selects N
4429 (the number of CPUs), -3 selects N+1, and so on.
4432 Enable debug-object double-call_rcu() testing.
4435 Set time (s) after boot for CPU-hotplug testing.
4438 Set time (jiffies) between CPU-hotplug operations,
4439 or zero to disable CPU-hotplug testing.
4442 Set the number of read-then-exit kthreads used
4444 task-exit processing.
4447 The number of times in a given read-then-exit
4448 episode that a set of read-then-exit kthreads
4453 read-then-exit testing episodes.
4456 Set task-shuffle interval (s). Shuffling tasks
4457 allows some CPUs to go into dyntick-idle mode
4462 is useful for hands-off automated testing.
4466 warnings, zero to disable.
4471 to any other stall-related activity.
4477 Disable interrupts while stalling if set.
4481 grace-period kthread to test RCU CPU stall
4482 warnings, zero to disable. If both stall_cpu
4507 Test RCU's dyntick-idle handling. See also the
4533 Use expedited grace-period primitives, for
4536 but can increase CPU utilization, degrade
4537 real-time latency, and degrade energy efficiency.
4541 Use only normal grace-period primitives,
4544 real-time latency, CPU utilization, and
4545 energy efficiency, but can expose users to
4546 increased grace-period latency. This parameter
4553 only normal grace-period primitives. No effect
4560 number avoids disturbing real-time workloads,
4565 messages. Disable with a value less than or equal
4577 force - Override the decision by the kernel to hide the
4605 Set test-start holdoff period. The purpose of
4614 but the default has already reduced the per-pass
4619 Set number of readers. The default value of -1
4628 Set the read-side critical-section duration,
4632 Specify the read-protection implementation to test.
4645 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
4653 reservetop= [X86-32]
4675 See Documentation/power/swsusp-and-swap-files.rst
4688 no Disable hibernation and resume.
4691 during restoration read-only).
4699 AMD-based UNRET and IBPB mitigations alone do not stop
4701 sibling threads. For that reason, STIBP is used on pro-
4705 off - no mitigation
4706 auto - automatically select a migitation
4707 auto,nosmt - automatically select a mitigation,
4711 ibpb - On AMD, mitigate short speculation
4716 ibpb,nosmt - Like "ibpb" above but will disable SMT
4720 unret - Force enable untrained return thunks,
4721 only effective on AMD f15h-f17h based
4723 unret,nosmt - Like unret, but will disable SMT when STIBP
4747 ring3mwait=disable
4748 [KNL] Disable ring 3 MONITOR/MWAIT feature on supported
4751 ro [KNL] Mount root device read-only on boot
4754 on Mark read-only kernel memory as read-only (default).
4755 off Leave read-only kernel memory writable for debugging.
4760 debug-uart get routed to the D+ and D- pins of the usb
4782 rw [KNL] Mount root device read-write on boot
4800 schedstats= [KNL,X86] Enable or disable scheduled statistics.
4801 Allowed values are enable and disable. This feature
4824 to 10 seconds for built-in smp_call_function()
4831 that requesting even small non-zero numbers of
4832 seconds can result in RCU CPU stall warnings,
4838 The default of -1 specifies a number of kthreads
4843 test before initiating CPU-hotplug operations.
4847 CPU-hotplug operations. Specifying zero (which
4848 is the default) disables CPU-hotplug operations.
4854 Non-zero values are useful for automated tests.
4867 preempt_disable() to disable CPU hotplug
4877 "wait" parameter. A value of -1 selects the
4878 default if all other weights are -1. However,
4880 value of -1 will instead select a weight of zero.
4885 non-zero "wait" parameter. See weight_single.
4892 this weighting can place serious IPI load
4898 non-zero "wait" parameter. See weight_single
4910 non-zero "wait" parameter. See weight_single
4917 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
4918 1 -- enable.
4926 selinux= [SELINUX] Disable or enable SELinux at boot time.
4929 0 -- disable.
4930 1 -- enable.
4933 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
4936 0 -- disable.
4937 1 -- enable.
4940 serialnumber [BUGS=X86-32]
4945 simeth= [IA-64]
4951 Disable merging of slabs with similar size. May be
4955 layout control by attackers can usually be
4959 unchanged). Debug options disable merging on their
4972 slub_debug can create guard zones around objects and
4979 memory cgroup sub-caches. 1 to enable, 0 to disable.
4981 Enabling this can lead to a very high number of debug
5012 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
5013 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
5014 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
5015 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
5016 smsc-ircc2.ircc_irq= [HW] IRQ line
5017 smsc-ircc2.ircc_dma= [HW] DMA channel
5018 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
5028 Default: -1 (no limit)
5031 [KNL] Should the soft-lockup detector generate panics.
5034 A value of 1 instructs the soft-lockup detector
5035 to panic the machine when a soft-lockup occurs. It is
5038 respective build-time switch to that functionality.
5041 [KNL] Should the soft-lockup detector generate
5046 See Documentation/admin-guide/laptops/sonypi.rst
5053 on - unconditionally enable, implies
5055 off - unconditionally disable, implies
5057 auto - kernel detects whether your CPU model is
5069 Selecting 'off' will disable both the kernel and
5072 Specific mitigations can also be selected manually:
5074 retpoline - replace indirect branches
5075 retpoline,generic - Retpolines
5076 retpoline,lfence - LFENCE; indirect branch
5077 retpoline,amd - alias for retpoline,lfence
5078 eibrs - enhanced IBRS
5079 eibrs,retpoline - enhanced IBRS + Retpolines
5080 eibrs,lfence - enhanced IBRS + LFENCE
5081 ibrs - use IBRS to protect kernel
5091 on - Unconditionally enable mitigations. Is
5094 off - Unconditionally disable mitigations. Is
5097 prctl - Indirect branch speculation is enabled,
5098 but mitigation can be enabled via prctl
5103 - Like "prctl" above, but only STIBP is
5109 - Same as "prctl" above, but all seccomp
5114 - Like "seccomp" above, but only STIBP is
5119 auto - Kernel selects the mitigation depending on
5129 [HW] Control Speculative Store Bypass (SSB) Disable mitigation
5137 is that such stores are unlikely and that they can
5142 store can be used in a cache side channel attack, for
5151 on - Unconditionally disable Speculative Store Bypass
5152 off - Unconditionally enable Speculative Store Bypass
5153 auto - Kernel detects whether the CPU model contains an
5159 prctl - Control Speculative Store Bypass per thread
5163 seccomp - Same as "prctl" above, but all seccomp threads
5164 will disable SSB unless they explicitly opt out.
5171 on,auto - On Power8 and Power9 insert a store-forwarding
5175 off - No action.
5192 off - not enabled
5194 warn - the kernel will emit rate limited warnings
5199 fatal - the kernel will send SIGBUS to applications
5211 Certain CPUs are vulnerable to an MDS-like
5212 exploit which can leak bits from the random
5216 microcode. However, the microcode fix can cause
5221 The microcode mitigation can be disabled with
5224 off: Disable mitigation and remove
5229 grace-period sequence counter wrap for the
5230 srcu_data structure's ->srcu_gp_seq_needed field.
5241 expediting. Set to zero to disable automatic
5245 Speculative Store Bypass Disable control
5252 force-on: Unconditionally enable mitigation for
5254 force-off: Unconditionally disable mitigation for
5271 stacktrace_filter=[function-list]
5273 will trace at boot up. function-list is a comma separated
5274 list of functions. This list can be changed at run
5281 Set the STI (builtin display/keyboard on the HP-PARISC
5283 as the initial boot-console.
5324 to global on non-NUMA machines)
5330 RPC calls that can be sent from the client to a
5349 controller if no parameter or 1 is given or disable
5350 it if 0 is given (See Documentation/admin-guide/cgroup-v1/memory.rst)
5352 swiotlb= [ARM,IA-64,PPC,MIPS,X86]
5354 <int> -- Number of I/O TLB slabs
5355 force -- force using of bounce buffers even if they
5357 noforce -- Never use bounce buffers (for debugging)
5371 Enable/disable old style sysfs layout for old udev
5381 Ignore sysrq setting - this boot parameter will
5389 cache size. See Documentation/networking/ip-sysctl.rst
5395 Specify "mem" (for Suspend-to-RAM) or "standby" (for
5400 wakeup-capable RTC alarm.
5406 -1: disable all active trip points in all thermal zones
5410 -1: disable all critical trip points in all thermal zones
5414 Set to disable actions on ACPI thermal zone
5418 1: disable ACPI thermal control
5421 -1: disable all passive trip points
5427 <deci-seconds>: poll all this frequency
5449 Prevent the CPU-hotplug component of torturing
5453 Dump the ftrace buffer at torture-test shutdown,
5454 even if there were no errors. This can be a
5457 with rotating-rust storage.
5473 trace_event=[event-list]
5475 to facilitate early boot debugging. The event-list is a
5479 trace_options=[option-list]
5480 [FTRACE] Enable or disable tracer options at boot.
5481 The option-list is a comma delimited list of options
5482 that can be enabled or disabled just as if you were
5510 frequency tracepoints such as irq or sched, can cause
5514 [FTRACE] enable this option to disable tracing when a
5515 warning is hit. This turns off "tracing_on". Tracing can
5523 This option can also be set at run time via the sysctl
5529 Can be used to control the default behavior of the system
5531 See Documentation/admin-guide/mm/transhuge.rst
5534 tsc= Disable clocksource stability checks for TSC.
5539 high-resolution timer mode on older hardware, and in
5542 Used to run time disable IRQ_TIME_ACCOUNTING on any
5544 can add overhead.
5548 [x86] nowatchdog: disable clocksource watchdog. Used
5565 on - Enable TSX on the system. Although there are
5568 several previous speculation-related CVEs, and
5572 off - Disable TSX on the system. (Note that this
5580 auto - Disable TSX if X86_BUG_TAA is present,
5585 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
5591 Similar to Micro-architectural Data Sampling (MDS)
5594 exploit against CPU internal buffers which can forward
5599 data can be used in a cache side channel attack, to
5606 full - Enable TAA mitigation on vulnerable CPUs
5609 full,nosmt - Enable TAA mitigation and disable SMT on
5612 vulnerable to cross-thread TAA attacks.
5613 off - Unconditionally disable TAA mitigation
5615 On MDS-affected machines, tsx_async_abort=off can be
5617 are mitigated with the same mechanism so in order to disable
5627 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
5633 See also Documentation/input/devices/joystick-parport.rst
5635 udbg-immortal [PPC] When debugging early kernel crashes that
5641 Set number of hash buckets for UDP/UDP-Lite connections
5643 uhci-hcd.ignore_oc=
5645 Some badly-designed motherboards generate lots of
5656 (default -1 = authorized except for wireless USB,
5662 for newly-detected USB devices (default 2). This
5690 [USB] Specifies timeout for the initial 64-byte
5694 usbcore.nousb [USB] Disable the USB subsystem
5697 [USB] A list of quirk entries to augment the built-in
5700 VendorID:ProductID:Flags. The IDs are 4-digit hex
5702 will change the built-in quirk; setting it if it is
5707 a 255-byte read);
5708 b = USB_QUIRK_RESET_RESUME (device can't resume
5710 c = USB_QUIRK_NO_SET_INTF (device can't handle
5711 Set-Interface requests);
5712 d = USB_QUIRK_CONFIG_INTF_STRINGS (device can't
5715 e = USB_QUIRK_RESET (device can't be reset
5719 bNumInterfaces count, and can't handle
5730 (bInterval-1).
5735 i = USB_QUIRK_DEVICE_QUALIFIER (device can't
5741 k = USB_QUIRK_NO_LPM (device can't handle Link
5765 usb-storage.delay_use=
5769 usb-storage.quirks=
5771 override the built-in unusual_devs list. List
5774 and Product ID values (4-digit hex numbers) and
5776 to a common usb-storage quirk flag as follows:
5818 medium is write-protected).
5827 1 - undefined instruction events
5828 2 - system calls
5829 4 - invalid data aborts
5830 8 - SIGSEGV faults
5831 16 - SIGBUS faults
5845 vdso=0: disable VDSO mapping
5847 vdso32= [X86] Control the 32-bit vDSO
5848 vdso32=1: enable 32-bit VDSO
5849 vdso32=0 or vdso32=2: disable 32-bit VDSO
5859 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
5861 vector= [IA-64,SMP]
5881 <size> := size (can use standard suffixes
5890 Can be used multiple times for multiple devices.
5892 vga= [BOOT,X86-32] Select a particular video mode
5894 Documentation/admin-guide/svga.rst.
5909 - Disable all of the above options
5912 size of <nn>. This can be used to increase the
5913 minimum size (128MB on x86). It can also be used to
5930 vsyscall= [X86-64]
5933 code). Most statically-linked binaries and older
5936 targets for exploits that can control RIP.
5957 see VGA-softcursor.txt. Default: 2 = underline.
5962 This is a 16-member array composed of values
5963 ranging from 0-255.
5968 This is a 16-member array composed of values
5969 ranging from 0-255.
5974 This is a 16-member array composed of values
5975 ranging from 0-255.
5980 Set system-wide default UTF-8 mode for all tty's.
5981 Default is 1, i.e. UTF-8 mode is enabled for all
5986 Format=<-1|0|1>
5987 Set system-wide default for whether a cursor
5988 is shown on new VTs. Default is -1,
5993 vt.italic= [VT] Default color for italic text; 0-15.
5996 vt.underline= [VT] Default color for underlined text; 0-15.
6000 see Documentation/watchdog/watchdog-parameters.rst
6001 or other driver-specific files in the
6013 If CONFIG_WQ_WATCHDOG is configured, workqueue can
6018 it can be updated at runtime by writing to the
6026 whatever reason, this option can be used. Note
6027 that this also can be controlled per-workqueue for
6031 Per-cpu workqueues are generally preferred because
6033 locality; unfortunately, per-cpu workqueues tend to
6036 Enabling this makes the per-cpu workqueues which
6051 forces round-robin CPU selection to flush out
6056 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
6060 x86_intel_mid_timer= [X86-32,APBT]
6066 xen_512gb_limit [KNL,X86-64,XEN]
6076 ide-disks -- unplug primary master IDE devices
6077 aux-ide-disks -- unplug non-primary-master IDE devices
6078 nics -- unplug network devices
6079 all -- unplug all emulated devices (NICs and IDE disks)
6080 unnecessary -- unplugging emulated devices is
6083 never -- do not unplug even if version check succeeds
6101 [KNL,X86,XEN] Disable the vector callback for Xen
6106 to Xen, for use by other domains. Can be also changed at runtime
6110 xen_timer_slop= [X86-64,XEN]
6133 Boolean parameter to disable using fifo event handling
6135 preferred over the 2-level event handling, as it is
6162 xhci-hcd.quirks [USB,KNL]
6164 host controller quirks. Meaning of each bit can be
6180 can be written using xmon commands.
6182 memory, and other data can't be written using