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 example, to map IOAPIC-ID decimal 10 to
2112 ivrs_hpet [HW,X86-64]
2113 Provide an override to the HPET-ID<->DEVICE-ID
2115 example, to map HPET-ID decimal 0 to
2119 ivrs_acpihid [HW,X86-64]
2120 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2122 example, to map UART-HID:UID AMD0020:0 to
2142 kernelcore= [KNL,X86,IA-64,PPC]
2145 the kernel for non-movable allocations. The requested
2155 subsystem. Note that allocations like PTEs-from-HighMem
2163 for non-movable allocations and remaining memory is used
2174 gdb or control-c on the dbgp connection. When
2175 not using this parameter you use sysrq-g to break into
2180 or a supported polling keyboard driver (non-usb).
2190 characters and can work in polling mode, you can use
2207 Configure the RouterBoard 532 series on-chip
2210 kmemleak= [KNL] Boot-time kmemleak enable/disable
2216 kprobe_event=[probe-list]
2218 The probe-list is a semicolon delimited list of probe
2264 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
2267 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
2269 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
2271 kvm-arm.vgic_v3_group0_trap=
2272 [KVM,ARM] Trap guest accesses to GICv3 group-0
2275 kvm-arm.vgic_v3_group1_trap=
2276 [KVM,ARM] Trap guest accesses to GICv3 group-1
2279 kvm-arm.vgic_v3_common_trap=
2283 kvm-arm.vgic_v4_enable=
2295 kvm-intel.ept= [KVM,Intel] Disable extended page tables
2299 kvm-intel.emulate_invalid_guest_state=
2300 [KVM,Intel] Disable emulation of invalid guest state.
2301 Ignored if kvm-intel.enable_unrestricted_guest=1, as
2307 kvm-intel.flexpriority=
2308 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
2311 kvm-intel.nested=
2315 kvm-intel.unrestricted_guest=
2316 [KVM,Intel] Disable unrestricted guest feature
2320 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2321 CVE-2018-3620.
2327 VMEXIT and VMENTER can leak host memory.
2332 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
2399 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
2405 lapic [X86-32,APIC] Enable the local APIC even if BIOS
2409 value for LAPIC timer one-shot implementation. Default
2417 libata.dma=0 Disable all PATA and SATA DMA
2444 first fan-out link behind PMP device. It does not
2451 The following configurations can be forced.
2458 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
2470 hot-unplug link recovery
2476 * disable: Disable this device.
2507 Set the number of locking read-acquisition kthreads.
2512 Set the number of locking write-acquisition kthreads.
2515 Set time (s) after boot for CPU-hotplug testing.
2518 Set time (s) between CPU-hotplug operations, or
2519 zero to disable CPU-hotplug testing.
2522 Set task-shuffle interval (jiffies). Shuffling
2523 tasks allows some CPUs to go into dyntick-idle
2528 is useful for hands-off automated testing.
2550 console loglevel will be printed to the console. It can
2561 7 (KERN_DEBUG) debug-level messages
2571 logo.nologo [FB] Disables display of the built-in Linux logo.
2579 lp=auto printer driver. 'lp=reset' (which can be
2589 an IEEE 1284-compliant printer is attached; if
2595 time-consuming boot-time autodetection (up to 250 ms per
2616 machvec= [IA-64] Force the use of a particular machine-vector
2622 Example: machtype=lemote-yeeloong-2f-7inch
2630 bootup you can bring up the other plugged cpu by executing
2637 (loop.max_loop) unconditionally pre-created at init time. The default
2640 devices can be requested on-demand with the
2641 /dev/loop-control interface.
2643 mce [X86-32] Machine Check Exception
2645 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.rst
2648 See Documentation/admin-guide/md.rst.
2655 Control mitigation for the Micro-architectural Data
2659 internal buffers which can forward information to a
2663 forwarded data can be used in a cache side channel
2670 full - Enable MDS mitigation on vulnerable CPUs
2671 full,nosmt - Enable MDS mitigation and disable
2673 off - Unconditionally disable MDS mitigation
2675 On TAA-affected machines, mds=off can be prevented by
2677 mitigated with the same mechanism so in order to disable
2684 For details see: Documentation/admin-guide/hw-vuln/mds.rst
2703 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
2708 per-device physically contiguous DMA buffers.
2716 See Documentation/admin-guide/mm/memory-hotplug.rst.
2720 Such memmap=exactmap lines can be constructed based on
2729 Multiple different regions can be specified,
2741 Example: Exclude memory from 0x18690000-0x1869ffff
2755 memmap=<size>%<offset>-<oldtype>+<newtype>
2757 from <oldtype> to <newtype>. If "-<oldtype>" is left
2772 repeatable BIOS-originated corruption always
2773 affects the same memory, you can use memmap=
2789 default : 0 <disable>
2797 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
2805 Refer to Documentation/virt/kvm/amd-memory-encryption.rst
2806 for details on when memory encryption can be activated.
2809 s2idle - Suspend-To-Idle
2810 shallow - Power-On Suspend or equivalent (if supported)
2811 deep - Suspend-To-RAM or equivalent (if supported)
2812 See Documentation/admin-guide/pm/sleep-states.rst.
2815 See Documentation/admin-guide/media/meye.rst.
2817 mfgpt_irq= [IA-32] Specify the IRQ to use for the
2818 Multi-Function General Purpose Timers on AMD Geode
2821 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
2824 problem by letting the user disable the workaround.
2835 0 - The attached screen is the 3.5" TFT
2836 1 - The attached screen is the 7" TFT
2837 2 - The VGA Shield is attached (1024x768)
2841 b - Enable backlight. The TFT backlight pin will be
2845 c - Enable the s3c camera interface.
2846 t - Reserved for enabling touchscreen support. The
2848 kernel as of 2.6.30, a preliminary port can be found
2850 https://repo.or.cz/w/linux-2.6/mini2440.git
2855 arch-independent options, each of which is an
2856 aggregation of existing arch-specific options.
2859 Disable all optional CPU mitigations. This
2869 ssbd=force-off [ARM64]
2888 have other ways of avoiding SMT-based attacks.
2922 full - Enable mitigation on vulnerable CPUs
2924 full,nosmt - Enable mitigation and disable SMT on
2927 off - Unconditionally disable mitigation
2930 mmio_stale_data=off can be prevented by an active
2933 disable this mitigation, you need to specify
2940 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
2948 module_blacklist= [KNL] Do not load a comma-separated list of
2962 movablecore= [KNL,X86,IA-64,PPC]
2973 movable_node [KNL] Boot-time switch to make hotplugable memory
2980 Format: <name>,<region-number>,<size>,<offset>
2983 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
2992 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
2996 boundary - index of last SLC block on Flex-OneNAND.
2998 lock - Configure if Flex-OneNAND boundary should be locked.
3005 See arch/arm/mach-s3c2412/mach-jive.c
3033 something different and driver-specific.
3039 0 to disable accounting
3044 See Documentation/admin-guide/nfs/nfsroot.rst.
3046 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3047 See Documentation/admin-guide/nfs/nfsroot.rst.
3050 See Documentation/admin-guide/nfs/nfsroot.rst.
3074 [NFS] enable 64-bit inode numbers.
3075 If zero, the NFS client will fake up a 32-bit inode
3077 of returning the full 64-bit number.
3078 The default is to return 64-bit inode numbers.
3091 that the client can send to the NFSv4.1 server.
3101 disabling idmapping, which can make migration from
3108 [NFS4] Specify an additional fixed unique ident-
3109 ification string that NFSv4 clients can insert into
3139 driver. A non-zero value sets the minimum interval
3151 NMI stack-backtrace request.
3160 0 - turn hardlockup detector in nmi_watchdog off
3161 1 - turn hardlockup detector in nmi_watchdog on
3165 To disable both hard and soft lockup detectors,
3170 These settings can be accessed at runtime via
3178 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
3182 no5lvl [X86-64] Disable 5-level paging mode. Forces
3183 kernel to use 4-level paging instead.
3189 Disable suspending of consoles during suspend and
3191 messages can reach various consoles while the rest
3203 Disable device dump. Device dump allows drivers to
3204 append dump data to vmcore so you can collect driver
3205 specified debug info. Drivers can append the data
3208 device dump can help save memory but the driver debug
3214 caches in the slab allocator. Saves per-node memory,
3225 noautogroup Disable scheduler automatic task group creation.
3234 nodelayacct [KNL] Disable per-task delay accounting
3236 nodsp [SH] Disable hardware DSP at boot time.
3238 noefi Disable EFI runtime services support.
3240 no_entry_flush [PPC] Don't flush the L1-D cache when entering the kernel.
3242 noexec [IA-64]
3245 On X86-32 available only on PAE configured kernels.
3246 noexec=on: enable non-executable mappings (default)
3247 noexec=off: disable non-executable mappings
3250 Disable SMAP (Supervisor Mode Access Prevention)
3254 Disable SMEP (Supervisor Mode Execution Prevention)
3257 noexec32 [X86-64]
3258 This affects only 32-bit executables.
3259 noexec32=on: enable non-executable mappings (default)
3261 noexec32=off: disable non-executable mappings
3264 nofpu [MIPS,SH] Disable hardware FPU at boot time.
3266 nofxsr [BUGS=X86-32] Disables x86 floating point extended
3268 legacy floating-point registers on task switch.
3270 nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
3272 nosmt [KNL,S390] Disable symmetric multithreading (SMT).
3275 [KNL,X86] Disable symmetric multithreading (SMT).
3276 nosmt=force: Force disable SMT, cannot be undone
3279 nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1
3283 nospectre_v2 [X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for
3289 [HW] Disable all mitigations for the Speculative Store Bypass vulnerability
3292 [PPC] Don't flush the L1-D cache after accessing user data.
3296 enabling legacy floating-point and sse state.
3321 nohalt [IA-64] Tells the kernel not to use the power saving
3323 power-consumption. On the positive side, it reduces
3324 interrupt wake-up latency, which may improve performance
3326 real-time systems.
3328 nohibernate [HIBERNATION] Disable hibernation and resume.
3330 nohz= [KNL] Boottime enable/disable dynamic ticks
3346 noirqdebug [X86-32] Disables the code which attempts to detect and
3347 disable unhandled interrupt sources.
3357 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
3359 [Deprecated - use intremap=off]
3361 nointroute [IA-64]
3363 noinvpcid [X86] Disable the INVPCID cpu feature.
3365 nojitter [IA-64] Disables jitter checking for ITC timers.
3367 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
3369 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
3372 no-vmw-sched-clock
3373 [X86,PV_OPS] Disable paravirtualized VMware scheduler
3376 no-steal-acc [X86,PV_OPS,ARM64] Disable paravirtualized steal time
3380 nolapic [X86-32,APIC] Do not enable or use the local APIC.
3382 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
3387 nomca [IA-64] Disable machine check abort handling
3389 nomce [X86-32] Disable Machine Check Exception
3391 nomfgpt [X86-32] Disable Multi-Function General Purpose
3394 nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to
3398 nomodule Disable module load
3400 nopat [X86] Disable PAT (page attribute table extension of
3403 nopcid [X86-64] Disable the PCID cpu feature.
3408 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
3411 nordrand [X86] Disable kernel use of the RDRAND and
3419 no-scroll [VGA] Disables scrollback.
3420 This is required for the Braillex ib80-piezo Braille
3423 nosbagart [IA-64]
3425 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
3428 and disable the IO APIC. legacy for "maxcpus=0".
3430 nosoftlockup [KNL] Disable the soft-lockup detector.
3434 nowatchdog [KNL] Disable both lockup detectors, i.e.
3435 soft-lockup and NMI watchdog (hard-lockup).
3439 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
3447 2. PIC interrupts also depend on CPU0. CPU0 can't be
3452 If the dependencies are under your control, you can
3457 cycles, each HW thread of the CTOP can run
3464 nptcg= [IA-64] Override max number of concurrent global TLB
3472 runtime you can physically add extra cpu until it reaches
3473 n. So during boot up some boot time memory for per-cpu
3474 variables need be pre-allocated for later physical cpu
3479 numa_balancing= [KNL,X86] Enable or disable automatic NUMA balancing.
3480 Allowed values are enable and disable
3483 'node', 'default' can be specified
3484 This can be set from sysctl after boot.
3485 See Documentation/admin-guide/sysctl/vm.rst for details.
3488 See Documentation/core-api/debugging-via-ohci1394.rst for more
3527 running on a platform with a direct-mapped memory-side
3528 cache, and this parameter can be used to
3529 override/disable that behavior. The state of the flag
3530 can be read from sysfs at:
3533 page_owner= [KNL] Boot-time page_owner enabling option.
3536 we can turn it on.
3539 page_poison= [KNL] Boot-time parameter changing the state of
3552 User can chose combination of the following bits:
3565 The optional switch "nousertaint" can be utilized to
3569 See Documentation/admin-guide/tainted-kernels.rst for
3570 extra details on the taint flags that users can pick
3577 Run kdump after running panic-notifiers and dumping
3581 because some panic notifiers can make the crashed
3596 possible conflicts). You can specify the base
3622 See also Documentation/admin-guide/blockdev/paride.rst.
3641 addresses can be specified after the base
3651 bios [X86-32] force use of PCI BIOS, don't access
3653 has a non-standard PCI host bridge.
3654 nobios [X86-32] disallow use of PCI BIOS, only direct
3660 data in IO port 0xCFC, both 32-bit).
3662 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
3663 the function, IO port 0xCFA, also 8-bit, sets
3665 through ports 0xC000-0xCFFF).
3669 enabled, this kernel boot option can be used to
3670 disable the use of PCIE advanced error reporting.
3671 nodomains [PCI] Disable support for multiple PCI
3672 root domains (aka PCI segments, in ACPI-speak).
3673 nommconf [X86] Disable use of MMCONFIG for PCI
3679 enabled, this kernel boot option can be used to
3680 disable the use of MSI interrupts system-wide.
3681 noioapicquirk [APIC] Disable all boot interrupt quirks.
3685 primary IO-APIC for bridges that cannot disable
3688 noioapicreroute [APIC] Disable workaround that uses the
3692 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
3710 assigned automatically to PCI devices. You can
3716 F0000h-100000h range.
3717 lastbus=N [X86] Scan all buses thru bus #N. Can be
3721 assign-busses [X86] Always assign all PCI bus
3742 skip_isa_align [X86] do not align io start addr, so can
3749 bfsort Sort PCI devices into breadth-first order.
3752 nobfsort Don't sort PCI devices into breadth-first order.
3753 pcie_bus_tune_off Disable PCIe MPS (Max Payload Size)
3754 tuning and use the BIOS-configured MPS defaults.
3761 or bus can support) for best performance.
3764 configuration allows peer-to-peer DMA between
3767 that hot-added devices will work.
3782 A PCI-PCI bridge can be specified if resource
3788 for 4096-byte alignment.
3789 ecrc= Enable/disable PCIe ECRC (transaction layer
3790 end-to-end CRC checking).
3811 realloc= Enable/disable reallocating PCI bridge resources
3819 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
3826 can resize a BAR to allow access to all VRAM.
3844 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
3846 off Disable ASPM.
3855 dpc-native Use native PCIe service for DPC only. May
3857 compat Disable native PCIe services (PME, AER, DPC, PCIe
3861 off Disable power management of all PCIe ports
3872 Keep all power-domains already enabled by bootloader on,
3878 See Documentation/admin-guide/blockdev/paride.rst.
3880 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
3893 See Documentation/admin-guide/blockdev/paride.rst.
3896 See Documentation/admin-guide/blockdev/paride.rst.
3898 pirq= [SMP,APIC] Manual mp-table setup
3899 See Documentation/x86/i386/IO-APIC.rst.
3903 See also Documentation/admin-guide/parport.rst.
3914 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
3923 { on | off | curr | res | no-curr | no-res }
3959 Disable Hardware Transactional Memory
3961 print-fatal-signals=
3967 coredump - etc.
3970 you might want to try "ulimit -i unlimited".
3977 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
3982 on - unlimited logging to /dev/kmsg from userspace
3983 off - logging to /dev/kmsg disabled
3984 ratelimit - ratelimit the logging
3988 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
3991 Limit processor to maximum C-state
3995 Ignore the _CST method to determine C-states,
4002 Param: "schedule" - profile schedule points.
4003 Param: "sleep" - profile D-state sleeping (millisecs).
4005 Param: "kvm" - profile VM exits.
4006 Param: <number> - step/bucket size as a power of 2 for
4016 psi= [KNL] Enable or disable pressure stall information
4036 See Documentation/admin-guide/blockdev/paride.rst.
4038 pti= [X86-64] Control Page Table Isolation of user and
4043 on - unconditionally enable
4044 off - unconditionally disable
4045 auto - kernel detects whether your CPU model is
4050 nopti [X86-64]
4054 [KNL] Number of legacy pty's. Overwrites compiled-in
4057 quiet [KNL] Disable most log messages
4062 See Documentation/admin-guide/md.rst.
4065 See Documentation/admin-guide/blockdev/ramdisk.rst.
4070 [KNL] Enable or disable trusting the use of the
4075 ras=option[,option,...] [KNL] RAS-specific options
4078 Disable the Correctable Errors Collector,
4083 except that the string "all" can be used to
4087 the specified list of CPUs to be no-callback CPUs.
4090 purpose, where "x" is "p" for RCU-preempt, and
4091 "s" for RCU-sched, and "N" is the CPU number.
4093 which can be useful for HPC and real-time
4094 workloads. It can also improve energy efficiency
4102 This improves the real-time response for the
4119 RCU grace-period cleanup.
4123 RCU grace-period initialization.
4127 RCU grace-period pre-initialization, that is,
4128 the propagation of recent CPU-hotplug changes up
4133 per-CPU rcuc kthreads. Defaults to a non-zero
4138 Disable autobalancing of the rcu_node combining
4141 cache-to-cache transfer latencies.
4147 and for NUMA systems with large remote-access
4160 Set delay from grace-period initialization to
4173 soliciting quiescent-state help from
4185 Set the SCHED_FIFO priority of the RCU per-CPU
4188 and for the RCU grace-period kthreads (rcu_bh,
4190 set, valid values are 1-99 and the default is 1
4191 (the least-favored priority). Otherwise, when
4192 RCU_BOOST is not set, valid values are 0-99 and
4193 the default is zero (non-realtime operation).
4199 the wakeup overhead on the global grace-period
4201 each group's NOCB grace-period kthread.
4209 batch limiting is re-enabled.
4213 RCU's force-quiescent-state scan will aggressively
4218 disable more aggressive help enlistment.
4227 Lazy RCU callbacks are those which RCU can
4231 Cause the grace-period kthread to get an extra
4233 it should at force-quiescent-state time.
4239 this specifies an rcu_read_unlock()-time delay
4243 of RCU-protected pointers after the relevant
4253 grace-period primitives such as call_rcu().
4264 grace-period primitives.
4267 Set test-start holdoff period. The purpose of
4286 Set number of RCU readers. The value -1 selects
4288 "n" less than -1 selects N-n+1, where N is again
4289 the number of CPUs. For example, -2 selects N
4290 (the number of CPUs), -3 selects N+1, and so on.
4291 A value of "n" less than or equal to -N selects
4304 complete. This is useful for hands-off automated
4311 Write-side holdoff between grace periods,
4328 Enable RCU grace-period forward-progress testing
4332 Specify the fraction of a CPU-stall-warning
4333 period to do tight-loop forward-progress testing.
4337 forward-progress tests.
4341 need_resched() during tight-loop forward-progress
4345 Use conditional/asynchronous update-side
4349 Use expedited update-side primitives, if available.
4352 Use normal (non-expedited) asynchronous
4353 update-side primitives, if available.
4356 Use normal (non-expedited) synchronous
4357 update-side primitives, if available. If all
4361 they are all non-zero.
4369 Leak an RCU-protected pointer out of the reader.
4370 This can of course result in splats, and is
4384 Set number of RCU readers. The value -1 selects
4385 N-1, where N is the number of CPUs. A value
4386 "n" less than -1 selects N-n-2, where N is again
4387 the number of CPUs. For example, -2 selects N
4388 (the number of CPUs), -3 selects N+1, and so on.
4391 Enable debug-object double-call_rcu() testing.
4394 Set time (s) after boot for CPU-hotplug testing.
4397 Set time (jiffies) between CPU-hotplug operations,
4398 or zero to disable CPU-hotplug testing.
4401 Set the number of read-then-exit kthreads used
4403 task-exit processing.
4406 The number of times in a given read-then-exit
4407 episode that a set of read-then-exit kthreads
4412 read-then-exit testing episodes.
4415 Set task-shuffle interval (s). Shuffling tasks
4416 allows some CPUs to go into dyntick-idle mode
4421 is useful for hands-off automated testing.
4425 warnings, zero to disable.
4430 to any other stall-related activity.
4436 Disable interrupts while stalling if set.
4440 grace-period kthread to test RCU CPU stall
4441 warnings, zero to disable. If both stall_cpu
4466 Test RCU's dyntick-idle handling. See also the
4492 Use expedited grace-period primitives, for
4495 but can increase CPU utilization, degrade
4496 real-time latency, and degrade energy efficiency.
4500 Use only normal grace-period primitives,
4503 real-time latency, CPU utilization, and
4504 energy efficiency, but can expose users to
4505 increased grace-period latency. This parameter
4512 only normal grace-period primitives. No effect
4519 number avoids disturbing real-time workloads,
4524 messages. Disable with a value less than or equal
4536 force - Override the decision by the kernel to hide the
4564 Set test-start holdoff period. The purpose of
4573 but the default has already reduced the per-pass
4578 Set number of readers. The default value of -1
4587 Set the read-side critical-section duration,
4591 Specify the read-protection implementation to test.
4604 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
4612 reservetop= [X86-32]
4634 See Documentation/power/swsusp-and-swap-files.rst
4647 no Disable hibernation and resume.
4650 during restoration read-only).
4658 off - no mitigation
4659 auto - automatically select a migitation
4660 auto,nosmt - automatically select a mitigation,
4664 ibpb - mitigate short speculation windows on
4667 unret - force enable untrained return thunks,
4668 only effective on AMD f15h-f17h
4670 unret,nosmt - like unret, will disable SMT when STIBP
4693 ring3mwait=disable
4694 [KNL] Disable ring 3 MONITOR/MWAIT feature on supported
4697 ro [KNL] Mount root device read-only on boot
4700 on Mark read-only kernel memory as read-only (default).
4701 off Leave read-only kernel memory writable for debugging.
4706 debug-uart get routed to the D+ and D- pins of the usb
4728 rw [KNL] Mount root device read-write on boot
4746 schedstats= [KNL,X86] Enable or disable scheduled statistics.
4747 Allowed values are enable and disable. This feature
4770 to 10 seconds for built-in smp_call_function()
4777 that requesting even small non-zero numbers of
4778 seconds can result in RCU CPU stall warnings,
4784 The default of -1 specifies a number of kthreads
4789 test before initiating CPU-hotplug operations.
4793 CPU-hotplug operations. Specifying zero (which
4794 is the default) disables CPU-hotplug operations.
4800 Non-zero values are useful for automated tests.
4813 preempt_disable() to disable CPU hotplug
4823 "wait" parameter. A value of -1 selects the
4824 default if all other weights are -1. However,
4826 value of -1 will instead select a weight of zero.
4831 non-zero "wait" parameter. See weight_single.
4838 this weighting can place serious IPI load
4844 non-zero "wait" parameter. See weight_single
4856 non-zero "wait" parameter. See weight_single
4863 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
4864 1 -- enable.
4872 selinux= [SELINUX] Disable or enable SELinux at boot time.
4875 0 -- disable.
4876 1 -- enable.
4879 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
4882 0 -- disable.
4883 1 -- enable.
4886 serialnumber [BUGS=X86-32]
4891 simeth= [IA-64]
4897 Disable merging of slabs with similar size. May be
4901 layout control by attackers can usually be
4905 unchanged). Debug options disable merging on their
4918 slub_debug can create guard zones around objects and
4925 memory cgroup sub-caches. 1 to enable, 0 to disable.
4927 Enabling this can lead to a very high number of debug
4958 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
4959 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
4960 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
4961 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
4962 smsc-ircc2.ircc_irq= [HW] IRQ line
4963 smsc-ircc2.ircc_dma= [HW] DMA channel
4964 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
4974 Default: -1 (no limit)
4977 [KNL] Should the soft-lockup detector generate panics.
4980 A value of 1 instructs the soft-lockup detector
4981 to panic the machine when a soft-lockup occurs. It is
4984 respective build-time switch to that functionality.
4987 [KNL] Should the soft-lockup detector generate
4992 See Documentation/admin-guide/laptops/sonypi.rst
4999 on - unconditionally enable, implies
5001 off - unconditionally disable, implies
5003 auto - kernel detects whether your CPU model is
5015 Selecting 'off' will disable both the kernel and
5018 Specific mitigations can also be selected manually:
5020 retpoline - replace indirect branches
5021 retpoline,generic - Retpolines
5022 retpoline,lfence - LFENCE; indirect branch
5023 retpoline,amd - alias for retpoline,lfence
5024 eibrs - enhanced IBRS
5025 eibrs,retpoline - enhanced IBRS + Retpolines
5026 eibrs,lfence - enhanced IBRS + LFENCE
5027 ibrs - use IBRS to protect kernel
5037 on - Unconditionally enable mitigations. Is
5040 off - Unconditionally disable mitigations. Is
5043 prctl - Indirect branch speculation is enabled,
5044 but mitigation can be enabled via prctl
5049 - Like "prctl" above, but only STIBP is
5055 - Same as "prctl" above, but all seccomp
5060 - Like "seccomp" above, but only STIBP is
5065 auto - Kernel selects the mitigation depending on
5075 [HW] Control Speculative Store Bypass (SSB) Disable mitigation
5083 is that such stores are unlikely and that they can
5088 store can be used in a cache side channel attack, for
5097 on - Unconditionally disable Speculative Store Bypass
5098 off - Unconditionally enable Speculative Store Bypass
5099 auto - Kernel detects whether the CPU model contains an
5105 prctl - Control Speculative Store Bypass per thread
5109 seccomp - Same as "prctl" above, but all seccomp threads
5110 will disable SSB unless they explicitly opt out.
5117 on,auto - On Power8 and Power9 insert a store-forwarding
5121 off - No action.
5138 off - not enabled
5140 warn - the kernel will emit rate limited warnings
5145 fatal - the kernel will send SIGBUS to applications
5157 Certain CPUs are vulnerable to an MDS-like
5158 exploit which can leak bits from the random
5162 microcode. However, the microcode fix can cause
5167 The microcode mitigation can be disabled with
5170 off: Disable mitigation and remove
5175 grace-period sequence counter wrap for the
5176 srcu_data structure's ->srcu_gp_seq_needed field.
5187 expediting. Set to zero to disable automatic
5191 Speculative Store Bypass Disable control
5198 force-on: Unconditionally enable mitigation for
5200 force-off: Unconditionally disable mitigation for
5217 stacktrace_filter=[function-list]
5219 will trace at boot up. function-list is a comma separated
5220 list of functions. This list can be changed at run
5227 Set the STI (builtin display/keyboard on the HP-PARISC
5229 as the initial boot-console.
5270 to global on non-NUMA machines)
5276 RPC calls that can be sent from the client to a
5295 controller if no parameter or 1 is given or disable
5296 it if 0 is given (See Documentation/admin-guide/cgroup-v1/memory.rst)
5298 swiotlb= [ARM,IA-64,PPC,MIPS,X86]
5300 <int> -- Number of I/O TLB slabs
5301 force -- force using of bounce buffers even if they
5303 noforce -- Never use bounce buffers (for debugging)
5317 Enable/disable old style sysfs layout for old udev
5327 Ignore sysrq setting - this boot parameter will
5335 cache size. See Documentation/networking/ip-sysctl.rst
5341 Specify "mem" (for Suspend-to-RAM) or "standby" (for
5346 wakeup-capable RTC alarm.
5352 -1: disable all active trip points in all thermal zones
5356 -1: disable all critical trip points in all thermal zones
5360 Set to disable actions on ACPI thermal zone
5364 1: disable ACPI thermal control
5367 -1: disable all passive trip points
5373 <deci-seconds>: poll all this frequency
5395 Prevent the CPU-hotplug component of torturing
5399 Dump the ftrace buffer at torture-test shutdown,
5400 even if there were no errors. This can be a
5403 with rotating-rust storage.
5419 trace_event=[event-list]
5421 to facilitate early boot debugging. The event-list is a
5425 trace_options=[option-list]
5426 [FTRACE] Enable or disable tracer options at boot.
5427 The option-list is a comma delimited list of options
5428 that can be enabled or disabled just as if you were
5456 frequency tracepoints such as irq or sched, can cause
5460 [FTRACE] enable this option to disable tracing when a
5461 warning is hit. This turns off "tracing_on". Tracing can
5469 This option can also be set at run time via the sysctl
5475 Can be used to control the default behavior of the system
5477 See Documentation/admin-guide/mm/transhuge.rst
5480 tsc= Disable clocksource stability checks for TSC.
5485 high-resolution timer mode on older hardware, and in
5488 Used to run time disable IRQ_TIME_ACCOUNTING on any
5490 can add overhead.
5494 [x86] nowatchdog: disable clocksource watchdog. Used
5511 on - Enable TSX on the system. Although there are
5514 several previous speculation-related CVEs, and
5518 off - Disable TSX on the system. (Note that this
5526 auto - Disable TSX if X86_BUG_TAA is present,
5531 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
5537 Similar to Micro-architectural Data Sampling (MDS)
5540 exploit against CPU internal buffers which can forward
5545 data can be used in a cache side channel attack, to
5552 full - Enable TAA mitigation on vulnerable CPUs
5555 full,nosmt - Enable TAA mitigation and disable SMT on
5558 vulnerable to cross-thread TAA attacks.
5559 off - Unconditionally disable TAA mitigation
5561 On MDS-affected machines, tsx_async_abort=off can be
5563 are mitigated with the same mechanism so in order to disable
5573 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
5579 See also Documentation/input/devices/joystick-parport.rst
5581 udbg-immortal [PPC] When debugging early kernel crashes that
5587 Set number of hash buckets for UDP/UDP-Lite connections
5589 uhci-hcd.ignore_oc=
5591 Some badly-designed motherboards generate lots of
5602 (default -1 = authorized except for wireless USB,
5608 for newly-detected USB devices (default 2). This
5636 [USB] Specifies timeout for the initial 64-byte
5640 usbcore.nousb [USB] Disable the USB subsystem
5643 [USB] A list of quirk entries to augment the built-in
5646 VendorID:ProductID:Flags. The IDs are 4-digit hex
5648 will change the built-in quirk; setting it if it is
5653 a 255-byte read);
5654 b = USB_QUIRK_RESET_RESUME (device can't resume
5656 c = USB_QUIRK_NO_SET_INTF (device can't handle
5657 Set-Interface requests);
5658 d = USB_QUIRK_CONFIG_INTF_STRINGS (device can't
5661 e = USB_QUIRK_RESET (device can't be reset
5665 bNumInterfaces count, and can't handle
5676 (bInterval-1).
5681 i = USB_QUIRK_DEVICE_QUALIFIER (device can't
5687 k = USB_QUIRK_NO_LPM (device can't handle Link
5711 usb-storage.delay_use=
5715 usb-storage.quirks=
5717 override the built-in unusual_devs list. List
5720 and Product ID values (4-digit hex numbers) and
5722 to a common usb-storage quirk flag as follows:
5764 medium is write-protected).
5773 1 - undefined instruction events
5774 2 - system calls
5775 4 - invalid data aborts
5776 8 - SIGSEGV faults
5777 16 - SIGBUS faults
5791 vdso=0: disable VDSO mapping
5793 vdso32= [X86] Control the 32-bit vDSO
5794 vdso32=1: enable 32-bit VDSO
5795 vdso32=0 or vdso32=2: disable 32-bit VDSO
5805 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
5807 vector= [IA-64,SMP]
5827 <size> := size (can use standard suffixes
5836 Can be used multiple times for multiple devices.
5838 vga= [BOOT,X86-32] Select a particular video mode
5840 Documentation/admin-guide/svga.rst.
5855 - Disable all of the above options
5858 size of <nn>. This can be used to increase the
5859 minimum size (128MB on x86). It can also be used to
5876 vsyscall= [X86-64]
5879 code). Most statically-linked binaries and older
5882 targets for exploits that can control RIP.
5903 see VGA-softcursor.txt. Default: 2 = underline.
5908 This is a 16-member array composed of values
5909 ranging from 0-255.
5914 This is a 16-member array composed of values
5915 ranging from 0-255.
5920 This is a 16-member array composed of values
5921 ranging from 0-255.
5926 Set system-wide default UTF-8 mode for all tty's.
5927 Default is 1, i.e. UTF-8 mode is enabled for all
5932 Format=<-1|0|1>
5933 Set system-wide default for whether a cursor
5934 is shown on new VTs. Default is -1,
5939 vt.italic= [VT] Default color for italic text; 0-15.
5942 vt.underline= [VT] Default color for underlined text; 0-15.
5946 see Documentation/watchdog/watchdog-parameters.rst
5947 or other driver-specific files in the
5959 If CONFIG_WQ_WATCHDOG is configured, workqueue can
5964 it can be updated at runtime by writing to the
5972 whatever reason, this option can be used. Note
5973 that this also can be controlled per-workqueue for
5977 Per-cpu workqueues are generally preferred because
5979 locality; unfortunately, per-cpu workqueues tend to
5982 Enabling this makes the per-cpu workqueues which
5997 forces round-robin CPU selection to flush out
6002 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
6006 x86_intel_mid_timer= [X86-32,APBT]
6012 xen_512gb_limit [KNL,X86-64,XEN]
6022 ide-disks -- unplug primary master IDE devices
6023 aux-ide-disks -- unplug non-primary-master IDE devices
6024 nics -- unplug network devices
6025 all -- unplug all emulated devices (NICs and IDE disks)
6026 unnecessary -- unplugging emulated devices is
6029 never -- do not unplug even if version check succeeds
6047 [KNL,X86,XEN] Disable the vector callback for Xen
6052 to Xen, for use by other domains. Can be also changed at runtime
6056 xen_timer_slop= [X86-64,XEN]
6079 Boolean parameter to disable using fifo event handling
6081 preferred over the 2-level event handling, as it is
6108 xhci-hcd.quirks [USB,KNL]
6110 host controller quirks. Meaning of each bit can be
6126 can be written using xmon commands.
6128 memory, and other data can't be written using