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
38 Disable AML predefined validation mechanism
39 This mechanism can repair the evaluation result to make
79 can interfere with legacy drivers.
111 by unsupported hardware/firmware features can result in
114 This facility can be used to prevent such uncontrolled
119 Disable auto-serialization of AML methods
122 auto-serialization feature.
126 acpi_no_memhotplug [ACPI] Disable memory hotplug. Useful for kdump
130 Disable installation of static SSDTs at early boot time
140 Ignore the ACPI-based watchdog interface (WDAT) and let
161 acpi_osi=! # disable all built-in OS vendor
163 acpi_osi=!! # enable all built-in OS vendor
165 acpi_osi= # disable all strings
167 'acpi_osi=!' can be used in combination with single or
169 vendor string(s). Note that such command can only
180 can make '_OSI("Windows 2000")' TRUE.
184 exist in the ACPI namespace. NOTE that such command can
189 1. 'acpi_osi=' can make 'CondRefOf(_OSI, Local1)'
192 'acpi_osi=!*' can be used in combination with single or
194 string(s). Note that such command can affect the
204 1. 'acpi_osi="Module Device" acpi_osi=!*' can make
206 2. 'acpi_osi=!* acpi_osi="Module Device"' can make
225 For broken nForce2 BIOS resulting in XT-PIC timer.
233 as soon as the kernel's real-mode entry point is called.
258 off: disable AGP support
263 See Documentation/sound/alsa-configuration.rst
270 align_va_addr= [X86-64]
275 CPU-intensive style benchmark, and it can vary highly in
278 32: only for 32-bit processes
279 64: only for 64-bit processes
280 on: enable for both 32- and 64-bit processes
281 off: disable for both 32- and 64-bit processes
290 amd_iommu= [HW,X86-64]
293 fullflush - enable flushing of IO/TLB entries when
297 off - do not initialize any AMD IOMMU found in
299 force_isolation - Force device isolation for all
305 amd_iommu_dump= [HW,X86-64]
311 amd_iommu_intr= [HW,X86-64]
314 legacy - Use legacy interrupt remapping mode.
315 vapic - Use virtual APIC mode, which allows IOMMU
317 This mode requires kvm-amd.avic=1.
331 Power management functions (SPARCstation-4/5 + deriv.)
333 Disable APC CPU standby support. SPARCstation-Fox does
334 not play well with APC CPU idle - disable it if you have
341 when initialising the APIC and IO-APIC components.
342 For X86-32, this can also be used to specify an APIC
362 to set it to "all" by meaning -- no limit here.
371 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
395 audit= [KNL] Enable the audit sub-system
397 0 | off - kernel audit is disabled and can not be
399 unset - kernel audit is initialized but disabled and
401 1 | on - kernel audit is initialized and partially
412 behavior is to disable the BAU (i.e. bau=0).
414 0 - Disable the BAU.
415 1 - Enable the BAU.
416 unset - Disable the BAU.
437 See Documentation/block/cmdline-partition.txt
447 Disable BERT OS support on buggy BIOSes.
452 bttv.pll= See Documentation/media/v4l-drivers/bttv.rst
461 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
475 inclusive. See arch/mips/include/asm/pgtable-bits.h
482 cgroup_disable= [KNL] Disable a particular controller
483 Format: {name of the controller(s) to disable}
485 - foo isn't auto-mounted if you mount all cgroups in
487 - foo isn't visible as an individually mountable
490 cut the overhead, others just disable the usage. So
493 cgroup_no_v1= [KNL] Disable one, multiple, all cgroup controllers in v1
500 nosocket -- Disable socket memory accounting.
501 nokmem -- Disable kernel memory accounting.
506 0 -- check protection applied by kernel (includes
508 1 -- check protection requested by application.
510 Value can be changed at runtime via
521 force such clocks to be always-on nor does it reserve
525 information, see Documentation/driver-api/clk.rst.
527 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
544 [X86-32] pit,hpet,tsc;
551 [X86-64] hpet,tsc
556 Enable/disable the eventstream feature of the ARM
557 architected timer so that code using WFE-based polling
558 loops can be debugged more effectively on production
562 Disable CPUID feature X for the kernel. See
571 Also note the kernel might malfunction if you disable
574 cma=nn[MG]@[start[MG][-end[MG]]]
581 include/linux/dma-contiguous.h
594 com20020= [HW,NET] ARCnet - COM20020 chipset
598 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
602 ARCnet - COM90xx chipset (memory-mapped buffers)
620 See Documentation/admin-guide/serial-console.rst for more
630 Start an early, polled-mode console on the 8250/16550
633 MMIO inter-register address stride is either 8-bit
634 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
638 the h/w is not re-initialized.
659 syscall, or to executing "dmesg -S --raw" or to reading
674 Enable/disable the CPU sampling based debugging.
675 0: default value, disable debugging
679 disable the cpuidle sub-system
682 disable the cpufreq sub-system
685 [X86] Delay for N microsec between assert and de-assert
695 [KNL] Using kexec, Linux can switch to a 'crash kernel'
705 start-[end] where start and end are both
722 low memory is needed to make sure DMA buffers for 32-bit
727 0: to disable low allocation.
732 [KNL] Disable crypto self-tests
746 See also Documentation/input/devices/joystick-parport.rst
750 Documentation/admin-guide/dynamic-debug-howto.rst for
764 [KNL] verbose self-tests
767 self-tests.
769 1 will print _a lot_ more information - normally
775 [KNL] Disable object debugging
799 default, it is disabled. We can avoid allocating huge
834 can be useful when debugging issues that require an SLB
837 disable= [IPV6]
846 against bounds-checking flaws in the kernel's
849 off Disable hardened usercopy checks.
852 Disable RADIX MMU mode on POWER9
859 disable BSP to wake up multiple CPUs without
864 Disable Dynamic DMA Window support. Use this if
882 Disable PIN 1 of APIC timer
883 Can be useful to work around chipset bugs.
885 dis_ucode_ldr [X86] Disable the microcode loader.
892 entries for DMA-API debugging code. One entry is
893 required per DMA-API allocation. Use this if the
894 DMA-API debugging code disables itself because the
898 With this option the DMA-API debugging driver
899 filter feature can be enabled at boot time. Just
901 The filter can be disabled or changed to another
909 Generic built-in EDID data sets are used, if one of
926 Control how the dt_cpu_ftrs device-tree binding is
936 what data is available or for reverse-engineering.
941 Documentation/admin-guide/dynamic-debug-howto.rst
948 nopku [X86] Disable Memory Protection Keys CPU feature found
962 stdout-path property in device tree's chosen node,
969 Start an early, polled-mode console on a Cadence
980 Start an early, polled-mode console on the 8250/16550
982 MMIO inter-register address stride is either 8-bit
983 (mmio) or 32-bit (mmio32 or mmio32be).
991 Start an early, polled-mode console on a pl011 serial
995 the driver will use only 32-bit accessors to read/write
999 Start an early, polled-mode console on a meson serial
1005 Start an early, polled-mode console on an msm serial
1011 Start an early, polled-mode console on an msm serial
1017 Start an early, polled-mode console on a serial port
1037 Start an early, polled-mode console on a lantiq serial
1050 Start an early, polled-mode console on the
1056 Start an early, polled-mode console on a Qualcomm
1077 Append ",keep" to not disable it when the real console
1080 Only one of vga, efi, serial, or usb debug port can
1088 You can find the port for a given device in
1098 The xen output can only be used by Xen PV guests.
1100 The sclp output can only be used on s390.
1110 off: disable H/W event reporting through EDAC.
1125 old_map [X86-64]: switch to the old ioremap-based EFI
1126 runtime services mapping. 32-bit still uses this one by
1128 nochunk: disable reading files in "chunks" in the EFI
1129 boot stub, as chunking can cause problems with some
1131 noruntime : disable EFI runtime services support
1135 Using this parameter you can use more than 50% of
1147 attribute is added to range 0x100000000-0x180000000 and
1148 0x10a0000000-0x1120000000.
1150 Using this parameter you can do debugging of EFI memmap
1151 related feature. For example, you can do debugging of
1159 Documentation/acpi/ssdt-overlays.txt for details.
1165 elanfreq= [X86-32]
1171 See Documentation/block/cfq-iosched.txt and
1172 Documentation/block/deadline-iosched.txt for details.
1187 Can be useful to work around chipset bugs
1194 0 -- permissive (log only, no denials).
1195 1 -- enforcing (deny and log).
1197 Value can be changed at runtime via /selinux/enforce.
1200 Disable Error Record Serialization Table (ERST)
1217 See also Documentation/fault-injection/.
1223 [IA-64] Avoid check_sal_cache_flush which may hang on
1228 forcepae [X86-32]
1230 Many Pentium M systems disable PAE but may have a
1247 ftrace_filter=[function-list]
1249 tracer at boot up. function-list is a comma separated
1250 list of functions. This list can be changed at run
1254 ftrace_notrace=[function-list]
1256 function-list. This list can be changed at run time
1260 ftrace_graph_filter=[function-list]
1263 function-list is a comma separated list of functions
1264 that can be changed at run time by the
1267 ftrace_graph_notrace=[function-list]
1269 function-list. This list is a comma separated list of
1270 functions that can be changed at run time by the
1276 can be changed at run time by the max_graph_depth file
1283 See also Documentation/input/devices/joystick-parport.rst
1287 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
1291 gcov_persist= [GCOV] When non-zero (default), profiling data for
1324 gpio-mockup.gpio_mockup_ranges
1329 [KNL] Should the hard-lockup detector generate
1335 for 64-bit NUMA, off otherwise.
1338 hcl= [IA-64] SGI's Hardware Graph compatibility layer
1344 Disable Hardware Error Source Table (HEST) support;
1345 corresponding firmware-first mode error processing
1353 highres= [KNL] Enable/disable high resolution timer mode.
1362 hpet= [X86-32,HPET] option to control HPET usage
1363 Format: { enable (default) | disable | force |
1365 disable: disable HPET and use PIT instead
1373 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
1374 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
1375 On x86-64 and powerpc, this option can be specified
1378 x86-64 are 2M (when the CPU supports "pse") and 1G
1387 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1388 option. The value selected by this boot parameter can
1393 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1411 (disabled by default, and as a pre-condition
1413 i8042.direct [HW] Put keyboard port into non-translated mode
1414 i8042.dumbkbd [HW] Pretend that controller can only read data from
1419 i8042.noloop [HW] Disable the AUX Loopback command while probing
1427 suspend-to-ram transitions, only during s2r
1460 -1 -- never invert brightness
1461 0 -- machine default
1462 1 -- force brightness inversion
1467 ide-core.nodma= [HW] (E)IDE subsystem
1473 ide-generic.probe-mask= [HW] (E)IDE subsystem
1485 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
1490 Poll forces a polling idle loop that can slightly
1496 idle=nomwait: Disable mwait for CPU C-states
1513 legacy only accept legacy-NaN binaries, if supported
1515 2008 only accept 2008-NaN binaries, if supported
1524 'relaxed' straps the emulator for both legacy-NaN and
1525 2008-NaN, whereas 'strict' enables legacy-NaN only on
1534 Ignore loglevel setting - this will print /all/
1542 print warning at first misuse. Can be changed via
1599 Formats: { "ima" | "ima-ng" | "ima-sig" }
1600 Default: "ima-ng"
1612 different crypto accelerators. This option can be used
1620 different crypto accelerators. This option can be used
1632 initcall_blacklist= [KNL] Do not execute a comma-separated list of
1633 initcall functions. Useful for debugging built-in
1640 default (disallow access to all but pkey 0). Can
1650 0 -- basic integrity auditing messages. (Default)
1651 1 -- additional integrity auditing messages.
1657 Disable intel iommu driver.
1666 for io virtual address below 32-bit forcing dual
1668 than 32-bit addressing. The default is to look
1669 for translation below 32-bit and if not available
1688 could harm performance of some high-throughput
1697 1 to 9 specify maximum depth of C-state.
1700 disable
1707 used along with the hardware-managed P-states (HWP)
1711 in favor of acpi-cpufreq. Forcing the intel_pstate driver
1712 instead of acpi-cpufreq may disable platform features, such
1714 P-States information being indicated to OSPM and therefore
1717 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
1730 Allow per-logical-CPU P-State performance control limits using
1733 intremap= [X86-64, Intel-IOMMU]
1735 off disable Interrupt Remapping
1736 nosid disable Source ID checking
1738 BIOS x2APIC opt-out request will be ignored
1739 nopost disable Interrupt Posting
1741 iomem= Disable strict checking of access to MMIO memory
1758 Disable IOMMU bypass, using IOMMU for PCI devices.
1763 0 - Use IOMMU translation for DMA.
1764 1 - Bypass the IOMMU for DMA.
1765 unset - Use IOMMU translation for DMA.
1817 [Deprecated - use cpusets instead]
1818 Format: [flag-list,]<cpu-list>
1824 Disable the tick when a single task runs.
1841 advised to use cpusets instead to disable scheduler load
1843 It offers a much more flexible interface where CPUs can
1846 You can move a process onto or off an "isolated" CPU via
1849 "number of CPUs in system - 1".
1851 The format of <cpu-list> is described above.
1858 Provide an override to the IOAPIC-ID<->DEVICE-ID
1860 example, to map IOAPIC-ID decimal 10 to
1865 Provide an override to the HPET-ID<->DEVICE-ID
1867 example, to map HPET-ID decimal 0 to
1872 Provide an override to the ACPI-HID:UID<->DEVICE-ID
1874 example, to map UART-HID:UID AMD0020:0 to
1894 kernelcore= [KNL,X86,IA-64,PPC]
1897 the kernel for non-movable allocations. The requested
1907 subsystem. Note that allocations like PTEs-from-HighMem
1915 for non-movable allocations and remaining memory is used
1926 gdb or control-c on the dbgp connection. When
1927 not using this parameter you use sysrq-g to break into
1932 or a supported polling keyboard driver (non-usb).
1944 Configure the RouterBoard 532 series on-chip
1947 kmemleak= [KNL] Boot-time kmemleak enable/disable
1988 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
1991 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
1993 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
1995 kvm-arm.vgic_v3_group0_trap=
1996 [KVM,ARM] Trap guest accesses to GICv3 group-0
1999 kvm-arm.vgic_v3_group1_trap=
2000 [KVM,ARM] Trap guest accesses to GICv3 group-1
2003 kvm-arm.vgic_v3_common_trap=
2007 kvm-arm.vgic_v4_enable=
2011 kvm-intel.ept= [KVM,Intel] Disable extended page tables
2015 kvm-intel.emulate_invalid_guest_state=
2019 kvm-intel.flexpriority=
2020 [KVM,Intel] Disable FlexPriority feature (TPR shadow).
2023 kvm-intel.nested=
2027 kvm-intel.unrestricted_guest=
2028 [KVM,Intel] Disable unrestricted guest feature
2032 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2033 CVE-2018-3620.
2039 VMEXIT and VMENTER can leak host memory.
2044 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
2111 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
2117 lapic [X86-32,APIC] Enable the local APIC even if BIOS
2121 value for LAPIC timer one-shot implementation. Default
2128 libata.dma=0 Disable all PATA and SATA DMA
2155 first fan-out link behind PMP device. It does not
2162 The following configurations can be forced.
2169 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
2181 hot-unplug link recovery
2187 * disable: Disable this device.
2210 Set the number of locking read-acquisition kthreads.
2215 Set the number of locking write-acquisition kthreads.
2218 Set time (s) after boot for CPU-hotplug testing.
2221 Set time (s) between CPU-hotplug operations, or
2222 zero to disable CPU-hotplug testing.
2225 Set task-shuffle interval (jiffies). Shuffling
2226 tasks allows some CPUs to go into dyntick-idle
2231 is useful for hands-off automated testing.
2253 console loglevel will be printed to the console. It can
2264 7 (KERN_DEBUG) debug-level messages
2274 logo.nologo [FB] Disables display of the built-in Linux logo.
2282 lp=auto printer driver. 'lp=reset' (which can be
2292 an IEEE 1284-compliant printer is attached; if
2298 time-consuming boot-time autodetection (up to 250 ms per
2313 machvec= [IA-64] Force the use of a particular machine-vector
2319 Example: machtype=lemote-yeeloong-2f-7inch
2327 bootup you can bring up the other plugged cpu by executing
2334 (loop.max_loop) unconditionally pre-created at init time. The default
2337 devices can be requested on-demand with the
2338 /dev/loop-control interface.
2340 mce [X86-32] Machine Check Exception
2342 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
2345 See Documentation/admin-guide/md.rst.
2352 Control mitigation for the Micro-architectural Data
2356 internal buffers which can forward information to a
2360 forwarded data can be used in a cache side channel
2367 full - Enable MDS mitigation on vulnerable CPUs
2368 full,nosmt - Enable MDS mitigation and disable
2370 off - Unconditionally disable MDS mitigation
2372 On TAA-affected machines, mds=off can be prevented by
2374 mitigated with the same mechanism so in order to disable
2381 For details see: Documentation/admin-guide/hw-vuln/mds.rst
2391 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
2396 per-device physically contiguous DMA buffers.
2404 See Documentation/memory-hotplug.txt.
2408 Such memmap=exactmap lines can be constructed based on
2417 Multiple different regions can be specified,
2429 Example: Exclude memory from 0x18690000-0x1869ffff
2443 memmap=<size>%<offset>-<oldtype>+<newtype>
2445 from <oldtype> to <newtype>. If "-<oldtype>" is left
2460 repeatable BIOS-originated corruption always
2461 affects the same memory, you can use memmap=
2477 default : 0 <disable>
2485 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
2493 Refer to Documentation/x86/amd-memory-encryption.txt
2494 for details on when memory encryption can be activated.
2497 s2idle - Suspend-To-Idle
2498 shallow - Power-On Suspend or equivalent (if supported)
2499 deep - Suspend-To-RAM or equivalent (if supported)
2500 See Documentation/admin-guide/pm/sleep-states.rst.
2503 See Documentation/media/v4l-drivers/meye.rst.
2505 mfgpt_irq= [IA-32] Specify the IRQ to use for the
2506 Multi-Function General Purpose Timers on AMD Geode
2509 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
2512 problem by letting the user disable the workaround.
2523 0 - The attached screen is the 3.5" TFT
2524 1 - The attached screen is the 7" TFT
2525 2 - The VGA Shield is attached (1024x768)
2529 b - Enable backlight. The TFT backlight pin will be
2533 c - Enable the s3c camera interface.
2534 t - Reserved for enabling touchscreen support. The
2536 kernel as of 2.6.30, a preliminary port can be found
2538 http://repo.or.cz/w/linux-2.6/mini2440.git
2543 arch-independent options, each of which is an
2544 aggregation of existing arch-specific options.
2547 Disable all optional CPU mitigations. This
2558 ssbd=force-off [ARM64]
2576 have other ways of avoiding SMT-based attacks.
2601 module_blacklist= [KNL] Do not load a comma-separated list of
2615 movablecore= [KNL,X86,IA-64,PPC]
2626 movable_node [KNL] Boot-time switch to make hotplugable memory
2633 Format: <name>,<region-number>,<size>,<offset>
2636 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
2645 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
2649 boundary - index of last SLC block on Flex-OneNAND.
2651 lock - Configure if Flex-OneNAND boundary should be locked.
2658 See arch/arm/mach-s3c2412/mach-jive.c
2686 something different and driver-specific.
2692 0 to disable accounting
2699 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
2727 [NFS] enable 64-bit inode numbers.
2728 If zero, the NFS client will fake up a 32-bit inode
2730 of returning the full 64-bit number.
2731 The default is to return 64-bit inode numbers.
2744 that the client can send to the NFSv4.1 server.
2754 disabling idmapping, which can make migration from
2761 [NFS4] Specify an additional fixed unique ident-
2762 ification string that NFSv4 clients can insert into
2792 driver. A non-zero value sets the minimum interval
2809 0 - turn hardlockup detector in nmi_watchdog off
2810 1 - turn hardlockup detector in nmi_watchdog on
2813 default). To disable both hard and soft lockup detectors,
2818 These settings can be accessed at runtime via
2826 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
2830 no5lvl [X86-64] Disable 5-level paging mode. Forces
2831 kernel to use 4-level paging instead.
2835 Disable suspending of consoles during suspend and
2837 messages can reach various consoles while the rest
2849 caches in the slab allocator. Saves per-node memory,
2860 noautogroup Disable scheduler automatic task group creation.
2869 nodelayacct [KNL] Disable per-task delay accounting
2871 nodsp [SH] Disable hardware DSP at boot time.
2873 noefi Disable EFI runtime services support.
2875 no_entry_flush [PPC] Don't flush the L1-D cache when entering the kernel.
2877 noexec [IA-64]
2880 On X86-32 available only on PAE configured kernels.
2881 noexec=on: enable non-executable mappings (default)
2882 noexec=off: disable non-executable mappings
2885 Disable SMAP (Supervisor Mode Access Prevention)
2889 Disable SMEP (Supervisor Mode Execution Prevention)
2892 noexec32 [X86-64]
2893 This affects only 32-bit executables.
2894 noexec32=on: enable non-executable mappings (default)
2896 noexec32=off: disable non-executable mappings
2899 nofpu [MIPS,SH] Disable hardware FPU at boot time.
2901 nofxsr [BUGS=X86-32] Disables x86 floating point extended
2903 legacy floating-point registers on task switch.
2905 nohugeiomap [KNL,x86] Disable kernel huge I/O mappings.
2907 nosmt [KNL,S390] Disable symmetric multithreading (SMT).
2910 [KNL,x86] Disable symmetric multithreading (SMT).
2911 nosmt=force: Force disable SMT, cannot be undone
2914 nospectre_v1 [X66, PPC] Disable mitigations for Spectre Variant 1
2918 nospectre_v2 [X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for
2924 [HW] Disable all mitigations for the Speculative Store Bypass vulnerability
2927 [PPC] Don't flush the L1-D cache after accessing user data.
2931 enabling legacy floating-point and sse state.
2956 nohalt [IA-64] Tells the kernel not to use the power saving
2958 power-consumption. On the positive side, it reduces
2959 interrupt wake-up latency, which may improve performance
2961 real-time systems.
2963 nohibernate [HIBERNATION] Disable hibernation and resume.
2965 nohz= [KNL] Boottime enable/disable dynamic ticks
2981 noirqdebug [X86-32] Disables the code which attempts to detect and
2982 disable unhandled interrupt sources.
2992 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
2994 [Deprecated - use intremap=off]
2996 nointroute [IA-64]
2998 noinvpcid [X86] Disable the INVPCID cpu feature.
3000 nojitter [IA-64] Disables jitter checking for ITC timers.
3002 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
3004 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
3007 no-vmw-sched-clock
3008 [X86,PV_OPS] Disable paravirtualized VMware scheduler
3011 no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
3015 nolapic [X86-32,APIC] Do not enable or use the local APIC.
3017 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
3022 nomca [IA-64] Disable machine check abort handling
3024 nomce [X86-32] Disable Machine Check Exception
3026 nomfgpt [X86-32] Disable Multi-Function General Purpose
3029 nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to
3033 nomodule Disable module load
3035 nopat [X86] Disable PAT (page attribute table extension of
3038 nopcid [X86-64] Disable the PCID cpu feature.
3043 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
3046 nordrand [X86] Disable kernel use of the RDRAND and
3054 no-scroll [VGA] Disables scrollback.
3055 This is required for the Braillex ib80-piezo Braille
3058 nosbagart [IA-64]
3060 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
3063 and disable the IO APIC. legacy for "maxcpus=0".
3065 nosoftlockup [KNL] Disable the soft-lockup detector.
3069 nowatchdog [KNL] Disable both lockup detectors, i.e.
3070 soft-lockup and NMI watchdog (hard-lockup).
3074 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
3082 2. PIC interrupts also depend on CPU0. CPU0 can't be
3087 If the dependencies are under your control, you can
3092 cycles, each HW thread of the CTOP can run
3099 nptcg= [IA-64] Override max number of concurrent global TLB
3107 runtime you can physically add extra cpu until it reaches
3108 n. So during boot up some boot time memory for per-cpu
3109 variables need be pre-allocated for later physical cpu
3114 numa_balancing= [KNL,X86] Enable or disable automatic NUMA balancing.
3115 Allowed values are enable and disable
3118 'node', 'default' can be specified
3119 This can be set from sysctl after boot.
3123 See Documentation/debugging-via-ohci1394.txt for more
3158 page_owner= [KNL] Boot-time page_owner enabling option.
3161 we can turn it on.
3164 page_poison= [KNL] Boot-time parameter changing the state of
3180 Run kdump after running panic-notifiers and dumping
3184 because some panic notifiers can make the crashed
3199 possible conflicts). You can specify the base
3244 addresses can be specified after the base
3254 bios [X86-32] force use of PCI BIOS, don't access
3256 has a non-standard PCI host bridge.
3257 nobios [X86-32] disallow use of PCI BIOS, only direct
3263 data in IO port 0xCFC, both 32-bit).
3265 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
3266 the function, IO port 0xCFA, also 8-bit, sets
3268 through ports 0xC000-0xCFFF).
3272 enabled, this kernel boot option can be used to
3273 disable the use of PCIE advanced error reporting.
3274 nodomains [PCI] Disable support for multiple PCI
3275 root domains (aka PCI segments, in ACPI-speak).
3276 nommconf [X86] Disable use of MMCONFIG for PCI
3282 enabled, this kernel boot option can be used to
3283 disable the use of MSI interrupts system-wide.
3284 noioapicquirk [APIC] Disable all boot interrupt quirks.
3288 primary IO-APIC for bridges that cannot disable
3291 noioapicreroute [APIC] Disable workaround that uses the
3295 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
3313 assigned automatically to PCI devices. You can
3319 F0000h-100000h range.
3320 lastbus=N [X86] Scan all buses thru bus #N. Can be
3324 assign-busses [X86] Always assign all PCI bus
3345 skip_isa_align [X86] do not align io start addr, so can
3352 bfsort Sort PCI devices into breadth-first order.
3355 nobfsort Don't sort PCI devices into breadth-first order.
3356 pcie_bus_tune_off Disable PCIe MPS (Max Payload Size)
3357 tuning and use the BIOS-configured MPS defaults.
3364 or bus can support) for best performance.
3367 configuration allows peer-to-peer DMA between
3370 that hot-added devices will work.
3385 PCI-PCI bridge can be specified, if resource
3391 ecrc= Enable/disable PCIe ECRC (transaction layer
3392 end-to-end CRC checking).
3406 realloc= Enable/disable reallocating PCI bridge resources
3414 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
3421 can resize a BAR to allow access to all VRAM.
3435 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
3437 off Disable ASPM.
3446 compat Disable native PCIe services (PME, AER, DPC, PCIe
3450 off Disable power management of all PCIe ports
3461 Keep all power-domains already enabled by bootloader on,
3469 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
3487 pirq= [SMP,APIC] Manual mp-table setup
3488 See Documentation/x86/i386/IO-APIC.txt.
3492 See also Documentation/admin-guide/parport.rst.
3500 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
3509 { on | off | curr | res | no-curr | no-res }
3545 Disable Hardware Transactional Memory
3547 print-fatal-signals=
3553 coredump - etc.
3556 you might want to try "ulimit -i unlimited".
3563 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
3568 on - unlimited logging to /dev/kmsg from userspace
3569 off - logging to /dev/kmsg disabled
3570 ratelimit - ratelimit the logging
3574 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
3577 Limit processor to maximum C-state
3581 Ignore the _CST method to determine C-states,
3588 Param: "schedule" - profile schedule points.
3589 Param: "sleep" - profile D-state sleeping (millisecs).
3591 Param: "kvm" - profile VM exits.
3592 Param: <number> - step/bucket size as a power of 2 for
3622 on - unconditionally enable
3623 off - unconditionally disable
3624 auto - kernel detects whether your CPU model is
3633 [KNL] Number of legacy pty's. Overwrites compiled-in
3636 quiet [KNL] Disable most log messages
3641 See Documentation/admin-guide/md.rst.
3647 [KNL] Enable or disable trusting the use of the
3652 ras=option[,option,...] [KNL] RAS-specific options
3655 Disable the Correctable Errors Collector,
3662 the specified list of CPUs to be no-callback CPUs.
3665 that purpose, where "x" is "b" for RCU-bh, "p"
3666 for RCU-preempt, and "s" for RCU-sched, and "N"
3668 offloaded CPUs, which can be useful for HPC and
3669 real-time workloads. It can also improve energy
3677 This improves the real-time response for the
3694 RCU grace-period cleanup.
3698 RCU grace-period initialization.
3702 RCU grace-period pre-initialization, that is,
3703 the propagation of recent CPU-hotplug changes up
3707 Disable autobalancing of the rcu_node combining
3710 cache-to-cache transfer latencies.
3716 and for NUMA systems with large remote-access
3723 soliciting quiescent-state help from
3727 Set delay from grace-period initialization to
3738 Set the SCHED_FIFO priority of the RCU per-CPU
3741 and for the RCU grace-period kthreads (rcu_bh,
3743 set, valid values are 1-99 and the default is 1
3744 (the least-favored priority). Otherwise, when
3745 RCU_BOOST is not set, valid values are 0-99 and
3746 the default is zero (non-realtime operation).
3752 on the per-CPU grace-period kthreads, but increases
3761 batch limiting is re-enabled.
3770 Lazy RCU callbacks are those which RCU can
3774 Cause the grace-period kthread to get an extra
3776 it should at force-quiescent-state time.
3782 grace-period primitives such as call_rcu().
3793 grace-period primitives.
3796 Set test-start holdoff period. The purpose of
3802 Set number of RCU readers. The value -1 selects
3804 "n" less than -1 selects N-n+1, where N is again
3805 the number of CPUs. For example, -2 selects N
3806 (the number of CPUs), -3 selects N+1, and so on.
3807 A value of "n" less than or equal to -N selects
3820 complete. This is useful for hands-off automated
3827 Write-side holdoff between grace periods,
3833 callback-flood tests.
3837 bursts of callbacks within a given callback-flood
3842 callback-flood test. Set this to zero to
3843 disable callback-flood testing.
3847 in a given burst of a callback-flood test.
3862 Use conditional/asynchronous update-side
3866 Use expedited update-side primitives, if available.
3869 Use normal (non-expedited) asynchronous
3870 update-side primitives, if available.
3873 Use normal (non-expedited) synchronous
3874 update-side primitives, if available. If all
3878 they are all non-zero.
3889 Set number of RCU readers. The value -1 selects
3890 N-1, where N is the number of CPUs. A value
3891 "n" less than -1 selects N-n-2, where N is again
3892 the number of CPUs. For example, -2 selects N
3893 (the number of CPUs), -3 selects N+1, and so on.
3896 Enable debug-object double-call_rcu() testing.
3899 Set time (s) after boot for CPU-hotplug testing.
3902 Set time (jiffies) between CPU-hotplug operations,
3903 or zero to disable CPU-hotplug testing.
3906 Set task-shuffle interval (s). Shuffling tasks
3907 allows some CPUs to go into dyntick-idle mode
3912 is useful for hands-off automated testing.
3916 warnings, zero to disable.
3922 Disable interrupts while stalling if set.
3945 Test RCU's dyntick-idle handling. See also the
3961 Use expedited grace-period primitives, for
3964 but can increase CPU utilization, degrade
3965 real-time latency, and degrade energy efficiency.
3969 Use only normal grace-period primitives,
3972 real-time latency, CPU utilization, and
3973 energy efficiency, but can expose users to
3974 increased grace-period latency. This parameter
3981 only normal grace-period primitives. No effect
3986 messages. Disable with a value less than or equal
4004 force - Override the decision by the kernel to hide the
4031 See Documentation/cgroup-v1/cpusets.txt.
4039 reservetop= [X86-32]
4061 See Documentation/power/swsusp-and-swap-files.txt
4074 no Disable hibernation and resume.
4077 during restoration read-only).
4096 ring3mwait=disable
4097 [KNL] Disable ring 3 MONITOR/MWAIT feature on supported
4100 ro [KNL] Mount root device read-only on boot
4103 on Mark read-only kernel memory as read-only (default).
4104 off Leave read-only kernel memory writable for debugging.
4109 debug-uart get routed to the D+ and D- pins of the usb
4131 rw [KNL] Mount root device read-write on boot
4149 schedstats= [KNL,X86] Enable or disable scheduled statistics.
4150 Allowed values are enable and disable. This feature
4158 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
4159 1 -- enable.
4169 selinux= [SELINUX] Disable or enable SELinux at boot time.
4172 0 -- disable.
4173 1 -- enable.
4175 If enabled at boot time, /selinux/disable can be used
4176 later to disable prior to initial policy load.
4178 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
4181 0 -- disable.
4182 1 -- enable.
4185 serialnumber [BUGS=X86-32]
4190 simeth= [IA-64]
4196 Disable merging of slabs with similar size. May be
4200 layout control by attackers can usually be
4204 unchanged). Debug options disable merging on their
4217 slub_debug can create guard zones around objects and
4224 memory cgroup sub-caches. 1 to enable, 0 to disable.
4226 Enabling this can lead to a very high number of debug
4257 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
4258 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
4259 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
4260 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
4261 smsc-ircc2.ircc_irq= [HW] IRQ line
4262 smsc-ircc2.ircc_dma= [HW] DMA channel
4263 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
4273 Default: -1 (no limit)
4276 [KNL] Should the soft-lockup detector generate panics.
4279 A nonzero value instructs the soft-lockup detector
4280 to panic the machine when a soft-lockup occurs. This
4282 which is the respective build-time switch to that
4286 [KNL] Should the soft-lockup detector generate
4298 on - unconditionally enable, implies
4300 off - unconditionally disable, implies
4302 auto - kernel detects whether your CPU model is
4314 Selecting 'off' will disable both the kernel and
4317 Specific mitigations can also be selected manually:
4319 retpoline - replace indirect branches
4320 retpoline,generic - google's original retpoline
4321 retpoline,amd - AMD-specific minimal thunk
4331 on - Unconditionally enable mitigations. Is
4334 off - Unconditionally disable mitigations. Is
4337 prctl - Indirect branch speculation is enabled,
4338 but mitigation can be enabled via prctl
4343 - Like "prctl" above, but only STIBP is
4349 - Same as "prctl" above, but all seccomp
4354 - Like "seccomp" above, but only STIBP is
4359 auto - Kernel selects the mitigation depending on
4369 [HW] Control Speculative Store Bypass (SSB) Disable mitigation
4377 is that such stores are unlikely and that they can
4382 store can be used in a cache side channel attack, for
4391 on - Unconditionally disable Speculative Store Bypass
4392 off - Unconditionally enable Speculative Store Bypass
4393 auto - Kernel detects whether the CPU model contains an
4399 prctl - Control Speculative Store Bypass per thread
4403 seccomp - Same as "prctl" above, but all seccomp threads
4404 will disable SSB unless they explicitly opt out.
4411 on,auto - On Power8 and Power9 insert a store-forwarding
4415 off - No action.
4429 Certain CPUs are vulnerable to an MDS-like
4430 exploit which can leak bits from the random
4434 microcode. However, the microcode fix can cause
4439 The microcode mitigation can be disabled with
4442 off: Disable mitigation and remove
4447 grace-period sequence counter wrap for the
4448 srcu_data structure's ->srcu_gp_seq_needed field.
4459 expediting. Set to zero to disable automatic
4463 Speculative Store Bypass Disable control
4470 force-on: Unconditionally enable mitigation for
4472 force-off: Unconditionally disable mitigation for
4489 stacktrace_filter=[function-list]
4491 will trace at boot up. function-list is a comma separated
4492 list of functions. This list can be changed at run
4499 Set the STI (builtin display/keyboard on the HP-PARISC
4501 as the initial boot-console.
4542 to global on non-NUMA machines)
4548 RPC calls that can be sent from the client to a
4562 controller if no parameter or 1 is given or disable
4563 it if 0 is given (See Documentation/cgroup-v1/memory.txt)
4565 swiotlb= [ARM,IA-64,PPC,MIPS,X86]
4567 <int> -- Number of I/O TLB slabs
4568 force -- force using of bounce buffers even if they
4570 noforce -- Never use bounce buffers (for debugging)
4575 Enable/disable old style sysfs layout for old udev
4585 Ignore sysrq setting - this boot parameter will
4593 cache size. See Documentation/networking/ip-sysctl.txt
4599 Specify "mem" (for Suspend-to-RAM) or "standby" (for
4604 wakeup-capable RTC alarm.
4610 -1: disable all active trip points in all thermal zones
4614 -1: disable all critical trip points in all thermal zones
4618 Set to disable actions on ACPI thermal zone
4622 1: disable ACPI thermal control
4625 -1: disable all passive trip points
4631 <deci-seconds>: poll all this frequency
4639 Enable the Transcendent memory driver if built-in.
4642 Default is on (1). Disable the usage of the cleancache
4646 Default is on (1). Disable the usage of the frontswap
4651 Default is on (1). Disable the driving of swap pages
4687 trace_event=[event-list]
4689 to facilitate early boot debugging. The event-list is a
4693 trace_options=[option-list]
4694 [FTRACE] Enable or disable tracer options at boot.
4695 The option-list is a comma delimited list of options
4696 that can be enabled or disabled just as if you were
4724 frequency tracepoints such as irq or sched, can cause
4728 [FTRACE] enable this option to disable tracing when a
4729 warning is hit. This turns off "tracing_on". Tracing can
4737 This option can also be set at run time via the sysctl
4743 Can be used to control the default behavior of the system
4745 See Documentation/admin-guide/mm/transhuge.rst
4748 tsc= Disable clocksource stability checks for TSC.
4753 high-resolution timer mode on older hardware, and in
4756 Used to run time disable IRQ_TIME_ACCOUNTING on any
4758 can add overhead.
4769 on - Enable TSX on the system. Although there are
4772 several previous speculation-related CVEs, and
4776 off - Disable TSX on the system. (Note that this
4784 auto - Disable TSX if X86_BUG_TAA is present,
4789 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
4795 Similar to Micro-architectural Data Sampling (MDS)
4798 exploit against CPU internal buffers which can forward
4803 data can be used in a cache side channel attack, to
4810 full - Enable TAA mitigation on vulnerable CPUs
4813 full,nosmt - Enable TAA mitigation and disable SMT on
4816 vulnerable to cross-thread TAA attacks.
4817 off - Unconditionally disable TAA mitigation
4819 On MDS-affected machines, tsx_async_abort=off can be
4821 are mitigated with the same mechanism so in order to disable
4831 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
4837 See also Documentation/input/devices/joystick-parport.rst
4839 udbg-immortal [PPC] When debugging early kernel crashes that
4845 Set number of hash buckets for UDP/UDP-Lite connections
4847 uhci-hcd.ignore_oc=
4849 Some badly-designed motherboards generate lots of
4860 (default -1 = authorized except for wireless USB,
4865 for newly-detected USB devices (default 2). This
4893 [USB] Specifies timeout for the initial 64-byte
4897 usbcore.nousb [USB] Disable the USB subsystem
4900 [USB] A list of quirk entries to augment the built-in
4903 VendorID:ProductID:Flags. The IDs are 4-digit hex
4905 will change the built-in quirk; setting it if it is
4910 a 255-byte read);
4911 b = USB_QUIRK_RESET_RESUME (device can't resume
4913 c = USB_QUIRK_NO_SET_INTF (device can't handle
4914 Set-Interface requests);
4915 d = USB_QUIRK_CONFIG_INTF_STRINGS (device can't
4918 e = USB_QUIRK_RESET (device can't be reset
4922 bNumInterfaces count, and can't handle
4933 (bInterval-1).
4938 i = USB_QUIRK_DEVICE_QUALIFIER (device can't
4944 k = USB_QUIRK_NO_LPM (device can't handle Link
4968 usb-storage.delay_use=
4972 usb-storage.quirks=
4974 override the built-in unusual_devs list. List
4977 and Product ID values (4-digit hex numbers) and
4979 to a common usb-storage quirk flag as follows:
5020 medium is write-protected).
5029 1 - undefined instruction events
5030 2 - system calls
5031 4 - invalid data aborts
5032 8 - SIGSEGV faults
5033 16 - SIGBUS faults
5047 vdso=0: disable VDSO mapping
5049 vdso32= [X86] Control the 32-bit vDSO
5050 vdso32=1: enable 32-bit VDSO
5051 vdso32=0 or vdso32=2: disable 32-bit VDSO
5061 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
5063 vector= [IA-64,SMP]
5083 <size> := size (can use standard suffixes
5092 Can be used multiple times for multiple devices.
5094 vga= [BOOT,X86-32] Select a particular video mode
5102 size of <nn>. This can be used to increase the
5103 minimum size (128MB on x86). It can also be used to
5120 vsyscall= [X86-64]
5123 code). Most statically-linked binaries and older
5126 targets for exploits that can control RIP.
5142 see VGA-softcursor.txt. Default: 2 = underline.
5147 This is a 16-member array composed of values
5148 ranging from 0-255.
5153 This is a 16-member array composed of values
5154 ranging from 0-255.
5159 This is a 16-member array composed of values
5160 ranging from 0-255.
5165 Set system-wide default UTF-8 mode for all tty's.
5166 Default is 1, i.e. UTF-8 mode is enabled for all
5171 Format=<-1|0|1>
5172 Set system-wide default for whether a cursor
5173 is shown on new VTs. Default is -1,
5178 vt.italic= [VT] Default color for italic text; 0-15.
5181 vt.underline= [VT] Default color for underlined text; 0-15.
5185 see Documentation/watchdog/watchdog-parameters.txt
5186 or other driver-specific files in the
5190 If CONFIG_WQ_WATCHDOG is configured, workqueue can
5195 it can be updated at runtime by writing to the
5203 whatever reason, this option can be used. Note
5204 that this also can be controlled per-workqueue for
5208 Per-cpu workqueues are generally preferred because
5210 locality; unfortunately, per-cpu workqueues tend to
5213 Enabling this makes the per-cpu workqueues which
5228 forces round-robin CPU selection to flush out
5233 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
5237 x86_intel_mid_timer= [X86-32,APBT]
5243 xen_512gb_limit [KNL,X86-64,XEN]
5253 ide-disks -- unplug primary master IDE devices
5254 aux-ide-disks -- unplug non-primary-master IDE devices
5255 nics -- unplug network devices
5256 all -- unplug all emulated devices (NICs and IDE disks)
5257 unnecessary -- unplugging emulated devices is
5260 never -- do not unplug even if version check succeeds
5276 to Xen, for use by other domains. Can be also changed at runtime
5292 xhci-hcd.quirks [USB,KNL]
5294 host controller quirks. Meaning of each bit can be