Lines Matching +full:- +full:- +full:disable +full:- +full:system
5 force -- enable ACPI if default was off
6 on -- enable ACPI but allow fallback to DT [arm64,riscv64]
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
58 Documentation/firmware-guide/acpi/debug.rst for more information about
69 Some values produce so much output that the system is
116 Format: <byte> or <bitmap-list>
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
220 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
225 For broken nForce2 BIOS resulting in XT-PIC timer.
234 as soon as the kernel's real-mode entry point is called.
255 behave incorrectly in some ways with respect to system
267 off: disable AGP support
272 See Documentation/sound/alsa-configuration.rst
279 align_va_addr= [X86-64]
284 CPU-intensive style benchmark, and it can vary highly in
287 32: only for 32-bit processes
288 64: only for 64-bit processes
289 on: enable for both 32- and 64-bit processes
290 off: disable for both 32- and 64-bit processes
300 Allow execve() of 32-bit applications and setting of the
302 subset of the CPUs support 32-bit EL0. When this
303 parameter is present, the set of CPUs supporting 32-bit
304 EL0 is indicated by /sys/devices/system/cpu/aarch32_el0
305 and hot-unplug operations may be restricted.
307 See Documentation/arch/arm64/asymmetric-32bit.rst for more
310 amd_iommu= [HW,X86-64]
311 Pass parameters to the AMD IOMMU driver in the system.
313 fullflush - Deprecated, equivalent to iommu.strict=1
314 off - do not initialize any AMD IOMMU found in
315 the system
316 force_isolation - Force device isolation for all
321 force_enable - Force enable the IOMMU on platforms known
324 pgtbl_v1 - Use v1 page table for DMA-API (Default).
325 pgtbl_v2 - Use v2 page table for DMA-API.
326 irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
328 amd_iommu_dump= [HW,X86-64]
334 amd_iommu_intr= [HW,X86-64]
337 legacy - Use legacy interrupt remapping mode.
338 vapic - Use virtual APIC mode, which allows IOMMU
340 This mode requires kvm-amd.avic=1.
344 disable
377 Power management functions (SPARCstation-4/5 + deriv.)
379 Disable APC CPU standby support. SPARCstation-Fox does
380 not play well with APC CPU idle - disable it if you have
381 APC and your system crashes randomly.
387 when initialising the APIC and IO-APIC components.
388 For X86-32, this can also be used to specify an APIC
408 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
411 0 -- disable.
412 1 -- enable.
415 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
418 arm64.nobti [ARM64] Unconditionally disable Branch Target
421 arm64.nomops [ARM64] Unconditionally disable Memory Copy and Memory
424 arm64.nomte [ARM64] Unconditionally disable Memory Tagging Extension
427 arm64.nopauth [ARM64] Unconditionally disable Pointer Authentication
430 arm64.nosme [ARM64] Unconditionally disable Scalable Matrix
433 arm64.nosve [ARM64] Unconditionally disable Scalable Vector
457 audit= [KNL] Enable the audit sub-system
459 0 | off - kernel audit is disabled and can not be
461 unset - kernel audit is initialized but disabled and
463 1 | on - kernel audit is initialized and partially
474 behavior is to disable the BAU (i.e. bau=0).
476 0 - Disable the BAU.
477 1 - Enable the BAU.
478 unset - Disable the BAU.
498 Disable BERT OS support on buggy BIOSes.
501 Disable BGRT to avoid flickering OEM logo.
505 See Documentation/block/cmdline-partition.rst
518 See Documentation/admin-guide/bootconfig.rst
523 bttv.pll= See Documentation/admin-guide/media/bttv.rst
532 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
545 the system trusted keyring to be used for certificate
551 inclusive. See arch/mips/include/asm/pgtable-bits.h
558 cgroup_disable= [KNL] Disable a particular controller or optional feature
559 Format: {name of the controller(s) or feature(s) to disable}
561 - foo isn't auto-mounted if you mount all cgroups in
563 - foo isn't visible as an individually mountable
565 - if foo is an optional feature then the feature is
569 cut the overhead, others just disable the usage. So
571 Specifying "pressure" disables per-cgroup pressure
574 cgroup_no_v1= [KNL] Disable cgroup controllers and named hierarchies in v1
585 nosocket -- Disable socket memory accounting.
586 nokmem -- Disable kernel memory accounting.
587 nobpf -- Disable BPF memory accounting.
592 0 -- check protection applied by kernel (includes
594 1 -- check protection requested by application.
604 Disable CPUID feature X for the kernel. See
606 numbers X. Note the Linux-specific bits are not necessarily
607 stable over kernel options, but the vendor-specific
618 Also note the kernel might malfunction if you disable
627 force such clocks to be always-on nor does it reserve
631 information, see Documentation/driver-api/clk.rst.
633 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
650 [X86-32] pit,hpet,tsc;
657 [X86-64] hpet,tsc
662 Enable/disable the eventstream feature of the ARM
663 architected timer so that code using WFE-based polling
677 clocksource-wdtest.holdoff= [KNL]
683 cma=nn[MG]@[start[MG][-end[MG]]]
694 Sets the size of kernel per-numa memory area for
696 per-numa CMA altogether. And If this option is not
698 With per-numa CMA enabled, DMA users on node nid will
725 com20020= [HW,NET] ARCnet - COM20020 chipset
729 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
733 ARCnet - COM90xx chipset (memory-mapped buffers)
762 See Documentation/admin-guide/serial-console.rst for more
772 Start an early, polled-mode console on the 8250/16550
775 MMIO inter-register address stride is either 8-bit
776 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
780 the h/w is not re-initialized.
786 Use to disable console output, i.e., to have kernel
807 syscall, or to executing "dmesg -S --raw" or to reading
822 Enable/disable the CPU sampling based debugging.
823 0: default value, disable debugging
831 disable the cpuidle sub-system
837 disable the cpufreq sub-system
845 [X86] Delay for N microsec between assert and de-assert
851 [SMP] Enable/disable parallel bringup of secondary CPUs
857 Run kdump after running panic-notifiers and dumping
870 [KNL, X86-64, ARM64, RISCV] Select a region under 4G first, and
873 See Documentation/admin-guide/kdump/kdump.rst for further details.
877 in the running system. The syntax of range is
878 start-[end] where start and end are both
880 Documentation/admin-guide/kdump/kdump.rst for an example.
883 [KNL, X86-64, ARM64, RISCV] range could be above 4G.
885 so could be above 4G if system have more than 4G ram
890 [KNL, X86-64, ARM64, RISCV] range under 4G. When crashkernel=X,high
892 above 4G, that cause second kernel crash on system
895 low memory is needed to make sure DMA buffers for 32-bit
899 --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
900 --> arm64: 128MiB
901 --> riscv: 128MiB
904 0: to disable low allocation.
909 [KNL] Disable crypto self-tests
917 csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
932 See also Documentation/input/devices/joystick-parport.rst
945 [KNL] verbose locking self-tests
948 self-tests.
950 (no extra messages), setting it to -1 (all bits set)
951 will print _a_lot_ more information - normally only
962 amount of memory for normal system use. The maximum
978 disabled and the system will work mostly the same as a
986 Format: { on, no-mount, off }
988 no-mount:
993 get a -EPERM as result when trying to register files
997 Default value is set in build-time with a kernel configuration.
1009 Documentation/admin-guide/mm/hugetlbpage.rst.
1023 delayacct [KNL] Enable per-task delay accounting
1070 disable= [IPV6]
1074 Disable RADIX MMU mode on POWER9
1077 Disable TLBIE instruction. Currently does not work
1085 disable BSP to wake up multiple CPUs without
1086 causing system reset or hang due to sending
1090 Disable Dynamic DMA Window support. Use this
1108 Disable PIN 1 of APIC timer
1111 dis_ucode_ldr [X86] Disable the microcode loader.
1118 entries for DMA-API debugging code. One entry is
1119 required per DMA-API allocation. Use this if the
1120 DMA-API debugging code disables itself because the
1124 With this option the DMA-API debugging driver
1144 are enabled. In order to disable RFDS mitigation all
1148 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1162 Generic built-in EDID data sets are used, if one of
1167 available in Documentation/admin-guide/edid.rst. An EDID
1179 Control how the dt_cpu_ftrs device-tree binding is
1189 what data is available or for reverse-engineering.
1194 Documentation/admin-guide/dynamic-debug-howto.rst
1205 determined by stdout-path property in device tree's
1210 Start an early, polled-mode console on a Cadence
1221 Start an early, polled-mode console on the 8250/16550
1223 MMIO inter-register address stride is either 8-bit
1224 (mmio) or 32-bit (mmio32 or mmio32be).
1234 Start an early, polled-mode console on a pl011 serial
1238 the driver will use only 32-bit accessors to read/write
1247 Start an early, polled-mode console on a meson serial
1253 Start an early, polled-mode console on an msm serial
1259 Start an early, polled-mode console on an msm serial
1265 Start an early, polled-mode console on a serial port
1271 Start an early, polled-mode console on a serial port
1277 Use RISC-V SBI (Supervisor Binary Interface) for early
1295 Start an early, polled-mode console on a lantiq serial
1309 Start an early, polled-mode, output-only console on the
1314 Start an early, polled-mode console on the
1320 Start an early, polled-mode console on a Qualcomm
1328 coherent non-x86 systems that use system memory for
1353 Append ",keep" to not disable it when the real console
1386 off: disable H/W event reporting through EDAC.
1398 disable_early_pci_dma: disable the busmaster bit on all
1400 nochunk: disable reading files in "chunks" in the EFI
1403 noruntime : disable EFI runtime services support
1407 claim. Specify efi=nosoftreserve to disable this
1409 (i.e. EFI_CONVENTIONAL_MEMORY / "System RAM").
1428 attribute is added to range 0x100000000-0x180000000 and
1429 0x10a0000000-0x1120000000.
1433 range 0x240000000-0x43fffffff.
1445 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1462 elanfreq= [X86-32]
1470 See Documentation/admin-guide/kdump/kdump.rst for details.
1486 0 -- permissive (log only, no denials).
1487 1 -- enforcing (deny and log).
1493 Disable Error Record Serialization Table (ERST)
1519 See also Documentation/fault-injection/.
1523 See Documentation/admin-guide/sysctl/net.rst for
1527 See Documentation/admin-guide/blockdev/floppy.rst.
1530 [IA-64] Avoid check_sal_cache_flush which may hang on
1535 forcepae [X86-32]
1537 Many Pentium M systems disable PAE but may have a
1571 ftrace_filter=[function-list]
1573 tracer at boot up. function-list is a comma-separated
1578 ftrace_notrace=[function-list]
1580 function-list. This list can be changed at run time
1584 ftrace_graph_filter=[function-list]
1587 function-list is a comma-separated list of functions
1591 ftrace_graph_notrace=[function-list]
1593 function-list. This list is a comma-separated list of
1613 off -- Don't create device links from firmware info.
1614 permissive -- Create device links from firmware info
1617 on -- Create device links from firmware info and use it
1619 rpm -- Like "on", but also use to order runtime PM.
1632 strict -- Default. Continue waiting on consumers to
1634 timeout -- Give up waiting on consumers and call
1644 See also Documentation/input/devices/joystick-parport.rst
1648 gart_fix_e820= [X86-64] disable the fix e820 for K8 GART
1665 force: Disable AVX to mitigate systems without
1670 off: Disable GDS mitigation.
1672 gcov_persist= [GCOV] When non-zero (default), profiling data for
1682 gpio-mockup.gpio_mockup_ranges
1685 gpio-mockup.gpio_mockup_named_lines
1717 against bounds-checking flaws in the kernel's
1720 off Disable hardened usercopy checks.
1723 [KNL] Should the hard-lockup detector generate
1729 for 64-bit NUMA, off otherwise.
1732 hcl= [IA-64] SGI's Hardware Graph compatibility layer
1738 Disable Hardware Error Source Table (HEST) support;
1739 corresponding firmware-first mode error processing
1746 no Disable hibernation and resume.
1749 during restoration read-only).
1756 highres= [KNL] Enable/disable high resolution timer mode.
1764 This allows setting the system's hostname during early
1775 hpet= [X86-32,HPET] option to control HPET usage
1776 Format: { enable (default) | disable | force |
1778 disable: disable HPET and use PIT instead
1792 number of pages to allocate per-node can be specified.
1793 See also Documentation/admin-guide/mm/hugetlbpage.rst.
1804 Documentation/admin-guide/mm/hugetlbpage.rst.
1815 boot-time allocation of gigantic hugepages is skipped.
1826 off: disable HVO
1843 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1849 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1866 (disabled by default, and as a pre-condition
1868 i8042.direct [HW] Put keyboard port into non-translated mode
1874 i8042.noloop [HW] Disable the AUX Loopback command while probing
1882 suspend-to-ram transitions, only during s2r
1906 -1 -- never invert brightness
1907 0 -- machine default
1908 1 -- force brightness inversion
1918 will use a lot of power and make the system run hot.
1922 idle=nomwait: Disable mwait for CPU C-states
1950 legacy only accept legacy-NaN binaries, if supported
1952 2008 only accept 2008-NaN binaries, if supported
1961 'relaxed' straps the emulator for both legacy-NaN and
1962 2008-NaN, whereas 'strict' enables legacy-NaN only on
1971 Ignore loglevel setting - this will print /all/
2038 Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" |
2039 "ima-sigv2" }
2040 Default: "ima-ng"
2072 initcall_blacklist= [KNL] Do not execute a comma-separated list of
2073 initcall functions. Useful for debugging built-in
2118 0 -- basic integrity auditing messages. (Default)
2119 1 -- additional integrity auditing messages.
2125 Disable intel iommu driver.
2147 could harm performance of some high-throughput
2151 provided by tboot because it makes the system
2156 1 to 9 specify maximum depth of C-state.
2159 disable
2165 algorithms for p-state selection. There are two
2166 P-state selection algorithms provided by
2169 on whether or not the hardware managed P-states
2176 used along with the hardware-managed P-states (HWP)
2180 in favor of acpi-cpufreq. Forcing the intel_pstate driver
2181 instead of acpi-cpufreq may disable platform features, such
2183 P-States information being indicated to OSPM and therefore
2186 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
2199 Allow per-logical-CPU P-State performance control limits using
2202 intremap= [X86-64, Intel-IOMMU]
2204 off disable Interrupt Remapping
2205 nosid disable Source ID checking
2207 BIOS x2APIC opt-out request will be ignored
2208 nopost disable Interrupt Posting
2210 iomem= Disable strict checking of access to MMIO memory
2227 Disable IOMMU bypass, using IOMMU for PCI devices.
2231 0 - Try to allocate a 32-bit DMA address first, before
2233 1 - Allocate directly from the full usable range,
2235 greater than 32-bit addressing.
2239 0 - Lazy mode.
2245 1 - Strict mode.
2248 unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
2250 legacy driver-specific options takes precedence.
2255 0 - Use IOMMU translation for DMA.
2256 1 - Bypass the IOMMU for DMA.
2257 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2259 io7= [HW] IO7 for Marvel-based Alpha systems
2274 See Documentation/admin-guide/nfs/nfsroot.rst.
2276 ipcmni_extend [KNL] Extend the maximum number of unique System V
2292 LPIs (and by consequence ITSs). Intended for system
2298 Enables support for pseudo-NMIs in the kernel. This
2317 [Deprecated - use cpusets instead]
2318 Format: [flag-list,]<cpu-list>
2324 Disable the tick when a single task runs.
2341 advised to use cpusets instead to disable scheduler load
2349 "number of CPUs in system - 1".
2375 The format of <cpu-list> is described above.
2379 ivrs_ioapic [HW,X86-64]
2380 Provide an override to the IOAPIC-ID<->DEVICE-ID
2384 For example, to map IOAPIC-ID decimal 10 to
2390 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2393 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2397 ivrs_hpet [HW,X86-64]
2398 Provide an override to the HPET-ID<->DEVICE-ID
2402 For example, to map HPET-ID decimal 10 to
2408 * To map HPET-ID decimal 0 to PCI device 00:14.0
2411 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2415 ivrs_acpihid [HW,X86-64]
2416 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2420 For example, to map UART-HID:UID AMD0020:0 to
2426 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2429 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2450 kernelcore= [KNL,X86,IA-64,PPC]
2453 the kernel for non-movable allocations. The requested
2455 system as ZONE_NORMAL. The remaining memory is used for
2463 subsystem. Note that allocations like PTEs-from-HighMem
2468 the form of "nn[KMGTPE]", a percentage of total system
2471 for non-movable allocations and remaining memory is used
2482 gdb or control-c on the dbgp connection. When
2483 not using this parameter you use sysrq-g to break into
2488 or a supported polling keyboard driver (non-usb).
2515 Configure the RouterBoard 532 series on-chip
2518 kmemleak= [KNL] Boot-time kmemleak enable/disable
2524 kprobe_event=[probe-list]
2526 The probe-list is a semicolon delimited list of probe
2556 execution by eliminating the write-protection faults
2601 back to huge pages. If the value is a non-zero N, KVM will
2606 kvm-amd.nested= [KVM,AMD] Control nested virtualization feature in
2609 kvm-amd.npt= [KVM,AMD] Control KVM's use of Nested Page Tables,
2610 a.k.a. Two-Dimensional Page Tables. Default is 1
2611 (enabled). Disable by KVM if hardware lacks support
2614 kvm-arm.mode=
2617 none: Forcefully disable KVM.
2619 nvhe: Standard nVHE-based mode, without support for
2622 protected: nVHE-based mode with support for guests whose
2625 nested: VHE-based mode with support for nested
2630 mode to "protected" will disable kexec and hibernation
2634 kvm-arm.vgic_v3_group0_trap=
2635 [KVM,ARM] Trap guest accesses to GICv3 group-0
2636 system registers
2638 kvm-arm.vgic_v3_group1_trap=
2639 [KVM,ARM] Trap guest accesses to GICv3 group-1
2640 system registers
2642 kvm-arm.vgic_v3_common_trap=
2644 system registers
2646 kvm-arm.vgic_v4_enable=
2651 Reserves given percentage from system memory area for
2654 By default it reserves 5% of total system memory.
2658 kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables,
2659 a.k.a. Two-Dimensional Page Tables. Default is 1
2660 (enabled). Disable by KVM if hardware lacks support
2663 kvm-intel.emulate_invalid_guest_state=
2665 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2671 kvm-intel.flexpriority=
2673 (TPR shadow). Default is 1 (enabled). Disable by KVM if
2676 kvm-intel.nested=
2680 kvm-intel.unrestricted_guest=
2683 is 1 (enabled). Disable by KVM if EPT is disabled or
2686 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2687 CVE-2018-3620.
2698 kvm-intel.vpid= [KVM,Intel] Control KVM's use of Virtual Processor
2700 (enabled). Disable by KVM if hardware lacks support
2718 on - enable the interface for the mitigation
2783 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
2789 lapic [X86-32,APIC] Enable the local APIC even if BIOS
2793 value for LAPIC timer one-shot implementation. Default
2801 libata.dma=0 Disable all PATA and SATA DMA
2816 libata.force= [LIBATA] Force configurations. The format is a comma-
2828 first fan-out link behind PMP device. It does not
2842 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
2849 * rstonce: only attempt one reset during hot-unplug
2852 * [no]dbdelay: Enable or disable the extra 200ms delay
2858 * [no]ncqtrim: Enable or disable queued DSM TRIM.
2860 * [no]ncqati: Enable or disable NCQ trim on ATI chipset.
2862 * [no]trim: Enable or disable (unqueued) TRIM.
2875 * [no]dmalog: Enable or disable the use of the
2878 * [no]iddevlog: Enable or disable access to the
2881 * [no]logdir: Enable or disable access to the general
2892 * [no]lpm: Enable or disable link power management.
2897 * [no]fua: Disable or enable FUA (Force Unit Access)
2902 * disable: Disable this device.
2931 Set the number of locking read-acquisition kthreads.
2936 Set the number of locking write-acquisition kthreads.
2939 Set time (s) after boot for CPU-hotplug testing.
2942 Set time (s) between CPU-hotplug operations, or
2943 zero to disable CPU-hotplug testing.
2946 Set task-shuffle interval (jiffies). Shuffling
2947 tasks allows some CPUs to go into dyntick-idle
2951 Set time (s) after boot system shutdown. This
2952 is useful for hands-off automated testing.
2968 Run the write-side locktorture kthreads at
2969 sched_set_fifo() real-time priority.
2982 0 (KERN_EMERG) system is unusable
2989 7 (KERN_DEBUG) debug-level messages
2999 logo.nologo [FB] Disables display of the built-in Linux logo.
3017 an IEEE 1284-compliant printer is attached; if
3023 time-consuming boot-time autodetection (up to 250 ms per
3044 machvec= [IA-64] Force the use of a particular machine-vector
3050 Example: machtype=lemote-yeeloong-2f-7inch
3052 max_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory greater
3059 "echo 1 > /sys/devices/system/cpu/cpuX/online". So maxcpus
3060 only takes effect during system bootup.
3065 (loop.max_loop) unconditionally pre-created at init time. The default
3068 devices can be requested on-demand with the
3069 /dev/loop-control interface.
3071 mce [X86-32] Machine Check Exception
3073 mce=option [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
3076 See Documentation/admin-guide/md.rst.
3083 Control mitigation for the Micro-architectural Data
3098 full - Enable MDS mitigation on vulnerable CPUs
3099 full,nosmt - Enable MDS mitigation and disable
3101 off - Unconditionally disable MDS mitigation
3103 On TAA-affected machines, mds=off can be prevented by
3105 mitigated with the same mechanism so in order to disable
3112 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3121 2 when the kernel is not able to see the whole system memory;
3126 [ARC,MICROBLAZE] - the limit applies only to low memory,
3129 [ARM64] - only limits memory covered by the linear
3139 if system memory of hypervisor is not sufficient.
3142 [ARM,MIPS] - override the memory layout reported by
3149 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3156 per-device physically contiguous DMA buffers.
3164 See Documentation/admin-guide/mm/memory-hotplug.rst.
3189 Example: Exclude memory from 0x18690000-0x1869ffff
3203 memmap=<size>%<offset>-<oldtype>+<newtype>
3205 from <oldtype> to <newtype>. If "-<oldtype>" is left
3220 repeatable BIOS-originated corruption always
3256 default : 0 <disable>
3264 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3270 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
3273 mem_sleep_default= [SUSPEND] Default system suspend mode:
3274 s2idle - Suspend-To-Idle
3275 shallow - Power-On Suspend or equivalent (if supported)
3276 deep - Suspend-To-RAM or equivalent (if supported)
3277 See Documentation/admin-guide/pm/sleep-states.rst.
3280 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
3282 mfgpt_irq= [IA-32] Specify the IRQ to use for the
3283 Multi-Function General Purpose Timers on AMD Geode
3286 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
3289 problem by letting the user disable the workaround.
3295 Enable or disable the microcode minimal revision
3298 min_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory below this
3305 0 - The attached screen is the 3.5" TFT
3306 1 - The attached screen is the 7" TFT
3307 2 - The VGA Shield is attached (1024x768)
3311 b - Enable backlight. The TFT backlight pin will be
3315 c - Enable the s3c camera interface.
3316 t - Reserved for enabling touchscreen support. The
3320 https://repo.or.cz/w/linux-2.6/mini2440.git
3325 arch-independent options, each of which is an
3326 aggregation of existing arch-specific options.
3332 Disable all optional CPU mitigations. This
3333 improves system performance, but it may also
3354 ssbd=force-off [ARM64]
3367 have other ways of avoiding SMT-based attacks.
3402 full - Enable mitigation on vulnerable CPUs
3404 full,nosmt - Enable mitigation and disable SMT on
3407 off - Unconditionally disable mitigation
3413 disable this mitigation, you need to specify
3420 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3425 probe on this module. Otherwise, enable/disable
3431 by default. To enable/disable async probing for a
3450 module_blacklist= [KNL] Do not load a comma-separated list of
3464 movablecore= [KNL,X86,IA-64,PPC]
3475 movable_node [KNL] Boot-time switch to make hotplugable memory
3482 Format: <name>,<region-number>,<size>,<offset>
3485 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3493 See arch/arm/mach-s3c/mach-jive.c
3529 something different and driver-specific.
3540 0 to disable accounting
3562 [NFS] enable 64-bit inode numbers.
3563 If zero, the NFS client will fake up a 32-bit inode
3565 of returning the full 64-bit number.
3566 The default is to return 64-bit inode numbers.
3601 [NFS4] Specify an additional fixed unique ident-
3604 UUID that is generated at system install time.
3632 driver. A non-zero value sets the minimum interval
3637 server-to-server copies for which this server is
3649 server-to-server copy, knfsd temporarily mounts
3656 See Documentation/admin-guide/nfs/nfsroot.rst.
3658 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3659 See Documentation/admin-guide/nfs/nfsroot.rst.
3662 See Documentation/admin-guide/nfs/nfsroot.rst.
3666 NMI stack-backtrace request.
3675 0 - turn hardlockup detector in nmi_watchdog off
3676 1 - turn hardlockup detector in nmi_watchdog on
3680 To disable both hard and soft lockup detectors,
3688 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
3692 no4lvl [RISCV] Disable 4-level and 5-level paging modes. Forces
3693 kernel to use 3-level paging instead.
3695 no5lvl [X86-64,RISCV] Disable 5-level paging mode. Forces
3696 kernel to use 4-level paging instead.
3699 caches in the slab allocator. Saves per-node memory,
3708 IOAPICs that may be present in the system.
3710 noautogroup Disable scheduler automatic task group creation.
3716 Disable suspending of consoles during suspend and
3719 of the system is being put to sleep (ie, while
3730 [KNL] Disable object debugging
3732 nodsp [SH] Disable hardware DSP at boot time.
3734 noefi Disable EFI runtime services support.
3736 no_entry_flush [PPC] Don't flush the L1-D cache when entering the kernel.
3738 noexec [IA-64]
3740 noexec32 [X86-64]
3741 This affects only 32-bit executables.
3742 noexec32=on: enable non-executable mappings (default)
3744 noexec32=off: disable non-executable mappings
3751 nofpu [MIPS,SH] Disable hardware FPU at boot time.
3755 nofxsr [BUGS=X86-32] Disables x86 floating point extended
3757 legacy floating-point registers on task switch.
3759 nohalt [IA-64] Tells the kernel not to use the power saving
3761 power-consumption. On the positive side, it reduces
3762 interrupt wake-up latency, which may improve performance
3764 real-time systems.
3774 compared. However, if this command-line option is
3780 nohibernate [HIBERNATION] Disable hibernation and resume.
3791 nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
3793 nohugevmalloc [KNL,X86,PPC,ARM64] Disable kernel huge vmalloc mappings.
3795 nohz= [KNL] Boottime enable/disable dynamic ticks
3815 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
3817 [Deprecated - use intremap=off]
3819 nointroute [IA-64]
3821 noinvpcid [X86] Disable the INVPCID cpu feature.
3825 noirqdebug [X86-32] Disables the code which attempts to detect and
3826 disable unhandled interrupt sources.
3830 nojitter [IA-64] Disables jitter checking for ITC timers.
3837 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
3840 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
3842 nolapic [X86-32,APIC] Do not enable or use the local APIC.
3844 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
3846 nomca [IA-64] Disable machine check abort handling
3848 nomce [X86-32] Disable Machine Check Exception
3850 nomfgpt [X86-32] Disable Multi-Function General Purpose
3853 nomodeset Disable kernel modesetting. Most systems' firmware
3856 not load if they could possibly displace the pre-
3857 initialized output. Only the system framebuffer will
3859 perform display-mode changes or accelerated rendering.
3863 nomodule Disable module load
3865 nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to
3869 nopat [X86] Disable PAT (page attribute table extension of
3872 nopcid [X86-64] Disable the PCID cpu feature.
3874 nopku [X86] Disable Memory Protection Keys CPU feature found
3877 nopti [X86-64]
3893 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
3899 nosbagart [IA-64]
3901 no-scroll [VGA] Disables scrollback.
3902 This is required for the Braillex ib80-piezo Braille
3905 nosgx [X86-64,SGX] Disables Intel SGX kernel support.
3908 Disable SMAP (Supervisor Mode Access Prevention)
3912 Disable SMEP (Supervisor Mode Execution Prevention)
3916 and disable the IO APIC. legacy for "maxcpus=0".
3918 nosmt [KNL,MIPS,PPC,S390] Disable symmetric multithreading (SMT).
3921 [KNL,X86,PPC] Disable symmetric multithreading (SMT).
3922 nosmt=force: Force disable SMT, cannot be undone
3925 nosoftlockup [KNL] Disable the soft-lockup detector.
3928 [HW] Disable all mitigations for the Speculative Store Bypass vulnerability
3930 nospectre_bhb [ARM64] Disable all mitigations for Spectre-BHB (branch
3931 history injection) vulnerability. System may allow data leaks
3934 nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1
3936 possible in the system.
3938 nospectre_v2 [X86,PPC_E500,ARM64] Disable all mitigations for
3940 vulnerability. System may allow data leaks with this
3943 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES] Disable paravirtualized
3953 [PPC] Don't flush the L1-D cache after accessing user data.
3956 Disable device dump. Device dump allows drivers to
3966 no-vmw-sched-clock
3967 [X86,PV_OPS] Disable paravirtualized VMware scheduler
3970 nowatchdog [KNL] Disable both lockup detectors, i.e.
3971 soft-lockup and NMI watchdog (hard-lockup).
3975 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
3983 enabling legacy floating-point and sse state.
4009 nptcg= [IA-64] Override max number of concurrent global TLB
4018 n. So during boot up some boot time memory for per-cpu
4019 variables need be pre-allocated for later physical cpu
4024 numa=off [KNL, ARM64, PPC, RISCV, SPARC, X86] Disable NUMA, Only
4027 numa_balancing= [KNL,ARM64,PPC,RISCV,S390,X86] Enable or disable automatic
4029 Allowed values are enable and disable
4034 See Documentation/admin-guide/sysctl/vm.rst for details.
4037 See Documentation/core-api/debugging-via-ohci1394.rst for more
4052 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4056 boundary - index of last SLC block on Flex-OneNAND.
4058 lock - Configure if Flex-OneNAND boundary should be locked.
4072 running on a platform with a direct-mapped memory-side
4074 override/disable that behavior. The state of the flag
4078 page_owner= [KNL] Boot-time page_owner enabling option.
4084 page_poison= [KNL] Boot-time parameter changing the state of
4111 See Documentation/admin-guide/tainted-kernels.rst for
4118 panic_print= Bitmask for printing system info when panic happens.
4121 bit 1: print system memory info
4163 Set to non-zero to probe primary and secondary ISA
4169 Set to non-zero if a chip is present that snoops speed
4217 Set to non-zero to probe tertiary and further ISA
4233 Set to non-zero to probe QDI controllers. By default
4238 Set to non-zero to probe Winbond controllers. Use
4280 devices in the system.
4285 bios [X86-32] force use of PCI BIOS, don't access
4287 has a non-standard PCI host bridge.
4288 nobios [X86-32] disallow use of PCI BIOS, only direct
4294 data in IO port 0xCFC, both 32-bit).
4296 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4297 the function, IO port 0xCFA, also 8-bit, sets
4299 through ports 0xC000-0xCFFF).
4304 disable the use of PCIE advanced error reporting.
4305 nodomains [PCI] Disable support for multiple PCI
4306 root domains (aka PCI segments, in ACPI-speak).
4307 nommconf [X86] Disable use of MMCONFIG for PCI
4314 disable the use of MSI interrupts system-wide.
4315 noioapicquirk [APIC] Disable all boot interrupt quirks.
4319 primary IO-APIC for bridges that cannot disable
4321 when the system masks IRQs.
4322 noioapicreroute [APIC] Disable workaround that uses the
4326 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4350 F0000h-100000h range.
4355 assign-busses [X86] Always assign all PCI bus
4376 <linux-pci@vger.kernel.org>.
4380 a bug to <linux-pci@vger.kernel.org>.
4392 bfsort Sort PCI devices into breadth-first order.
4395 nobfsort Don't sort PCI devices into breadth-first order.
4396 pcie_bus_tune_off Disable PCIe MPS (Max Payload Size)
4397 tuning and use the BIOS-configured MPS defaults.
4407 configuration allows peer-to-peer DMA between
4410 that hot-added devices will work.
4425 A PCI-PCI bridge can be specified if resource
4431 for 4096-byte alignment.
4432 ecrc= Enable/disable PCIe ECRC (transaction layer
4433 end-to-end CRC checking). Only effective if
4456 realloc= Enable/disable reallocating PCI bridge resources
4464 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4489 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
4491 off Disable ASPM.
4493 WARNING: Forcing ASPM on may cause system lockups.
4500 dpc-native Use native PCIe service for DPC only. May
4502 compat Disable native PCIe services (PME, AER, DPC, PCIe
4506 off Disable power management of all PCIe ports
4517 Keep all power-domains already enabled by bootloader on,
4522 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
4534 pirq= [SMP,APIC] Manual mp-table setup
4535 See Documentation/arch/x86/i386/IO-APIC.rst.
4539 See also Documentation/admin-guide/parport.rst.
4558 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4567 { on | off | curr | res | no-curr | no-res }
4603 Disable Hardware Transactional Memory
4607 none - Limited to cond_resched() calls
4608 voluntary - Limited to cond_resched() and might_sleep() calls
4609 full - Any section that isn't explicitly preempt disabled
4612 print-fatal-signals=
4618 coredump - etc.
4621 you might want to try "ulimit -i unlimited".
4628 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
4632 Disable console loglevel raise on oops, panic
4633 or lockdep-detected issues (only if lock debug is on).
4642 on - unlimited logging to /dev/kmsg from userspace
4643 off - logging to /dev/kmsg disabled
4644 ratelimit - ratelimit the logging
4648 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
4655 - 'always': traditional behavior always allows mem overrides.
4656 - 'ptrace': only allow mem overrides for active ptracers.
4657 - 'never': never allow mem overrides.
4661 Limit processor to maximum C-state
4665 Ignore the _CST method to determine C-states,
4672 Param: "schedule" - profile schedule points.
4673 Param: "kvm" - profile VM exits.
4674 Param: <number> - step/bucket size as a power of 2 for
4684 psi= [KNL] Enable or disable pressure stall information
4703 pti= [X86-64] Control Page Table Isolation of user and
4706 system calls and interrupts.
4708 on - unconditionally enable
4709 off - unconditionally disable
4710 auto - kernel detects whether your CPU model is
4716 [KNL] Number of legacy pty's. Overwrites compiled-in
4719 quiet [KNL] Disable most log messages
4724 Disable RADIX GTSE feature and use hcall for TLB
4728 See Documentation/admin-guide/md.rst.
4731 See Documentation/admin-guide/blockdev/ramdisk.rst.
4736 [KNL] Disable trusting the use of the CPU's
4741 [KNL] Disable trusting the use of the a seed
4746 [KNL] Enable or disable kernel stack offset
4750 cross-syscall address exposures. This is only
4753 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
4756 ras=option[,option,...] [KNL] RAS-specific options
4759 Disable the Correctable Errors Collector,
4762 rcu_nocbs[=cpu-list]
4767 enable the no-callback CPU mode, which prevents
4772 "p" for RCU-preempt, "s" for RCU-sched, and "g"
4776 and real-time workloads. It can also improve
4780 list of CPUs is set to no-callback mode from boot.
4784 no-callback mode from boot but the mode may be
4795 This improves the real-time response for the
4812 RCU grace-period cleanup.
4816 RCU grace-period initialization.
4820 RCU grace-period pre-initialization, that is,
4821 the propagation of recent CPU-hotplug changes up
4825 Set delay from grace-period initialization to
4838 soliciting quiescent-state help from
4850 Set the SCHED_FIFO priority of the RCU per-CPU
4853 and for the RCU grace-period kthreads (rcu_bh,
4855 set, valid values are 1-99 and the default is 1
4856 (the least-favored priority). Otherwise, when
4857 RCU_BOOST is not set, valid values are 0-99 and
4858 the default is zero (non-realtime operation).
4863 On callback-offloaded (rcu_nocbs) CPUs,
4866 use of the ->nocb_bypass list. However, in the
4867 common non-flooded case, RCU queues directly to
4868 the main ->cblist in order to avoid the extra
4869 overhead of the ->nocb_bypass list and its lock.
4871 a single jiffy, RCU pre-queues the callbacks into
4872 the ->nocb_bypass queue. The definition of "too
4881 batch limiting is re-enabled.
4885 RCU's force-quiescent-state scan will aggressively
4890 disable more aggressive help enlistment.
4893 Set the page-cache refill delay (in milliseconds)
4894 in response to low-memory conditions. The range
4898 Set the shift-right count to use to compute
4899 the callback-invocation batch limit bl from
4906 Please note that this callback-invocation batch
4907 limit applies only to non-offloaded callback
4913 Disable autobalancing of the rcu_node combining
4916 cache-to-cache transfer latencies.
4922 and for NUMA systems with large remote-access
4938 the wakeup overhead on the global grace-period
4940 each group's NOCB grace-period kthread.
4943 Cause the grace-period kthread to get an extra
4945 it should at force-quiescent-state time.
4958 this specifies an rcu_read_unlock()-time delay
4962 of RCU-protected pointers after the relevant
4972 per-CPU rcuc kthreads. Defaults to a non-zero
4976 But note that CONFIG_PREEMPT_RT=y kernels disable
4982 grace-period primitives such as call_rcu().
4993 grace-period primitives.
4996 Set test-start holdoff period. The purpose of
5014 Test the double-argument variant of kfree_rcu().
5016 rcuscale.kfree_rcu_test_single, both the single-
5017 and double-argument variants are tested.
5020 Test the single-argument variant of kfree_rcu().
5022 rcuscale.kfree_rcu_test_double, both the single-
5023 and double-argument variants are tested.
5037 does not affect the data-collection interval,
5042 Set number of RCU readers. The value -1 selects
5044 "n" less than -1 selects N-n+1, where N is again
5045 the number of CPUs. For example, -2 selects N
5046 (the number of CPUs), -3 selects N+1, and so on.
5047 A value of "n" less than or equal to -N selects
5059 Shut the system down after performance tests
5060 complete. This is useful for hands-off automated
5067 Write-side holdoff between grace periods,
5072 Additional write-side holdoff between grace
5090 for RCU grace-period forward-progress testing
5097 Specify the fraction of a CPU-stall-warning
5098 period to do tight-loop forward-progress testing.
5102 forward-progress tests.
5106 need_resched() during tight-loop forward-progress
5110 Use conditional/asynchronous update-side
5114 Use expedited update-side primitives, if available.
5117 Use normal (non-expedited) asynchronous
5118 update-side primitives, if available.
5121 Use normal (non-expedited) synchronous
5122 update-side primitives, if available. If all
5126 they are all non-zero.
5134 Leak an RCU-protected pointer out of the reader.
5149 Set number of RCU callback-offload togglers.
5154 callback-offload toggling attempts.
5157 Set number of RCU readers. The value -1 selects
5158 N-1, where N is the number of CPUs. A value
5159 "n" less than -1 selects N-n-2, where N is again
5160 the number of CPUs. For example, -2 selects N
5161 (the number of CPUs), -3 selects N+1, and so on.
5164 Enable debug-object double-call_rcu() testing.
5167 Set time (s) after boot for CPU-hotplug testing.
5170 Set time (jiffies) between CPU-hotplug operations,
5171 or zero to disable CPU-hotplug testing.
5174 Set the number of read-then-exit kthreads used
5176 task-exit processing.
5179 The number of times in a given read-then-exit
5180 episode that a set of read-then-exit kthreads
5185 read-then-exit testing episodes.
5188 Set task-shuffle interval (s). Shuffling tasks
5189 allows some CPUs to go into dyntick-idle mode
5193 Set time (s) after boot system shutdown. This
5194 is useful for hands-off automated testing.
5198 warnings, zero to disable.
5203 any other stall-related activity. Note that
5209 in scheduling-while-atomic splats.
5218 Disable interrupts while stalling if set.
5222 grace-period kthread to test RCU CPU stall
5223 warnings, zero to disable. If both stall_cpu
5248 Test RCU's dyntick-idle handling. See also the
5297 Use expedited grace-period primitives, for
5301 real-time latency, and degrade energy efficiency.
5305 Use only normal grace-period primitives,
5308 real-time latency, CPU utilization, and
5310 increased grace-period latency. This parameter
5317 only normal grace-period primitives. No effect
5323 post-boot attempt at an expedited RCU grace
5324 period to instead use normal non-expedited
5325 grace-period processing.
5333 set to the default value of -1.
5336 Set the minimum number of callback-queuing-time
5337 lock-contention events per jiffy required to
5338 cause the RCU Tasks flavors to switch to per-CPU
5341 the default value of -1.
5346 of -1 allows this to be automatically (and
5354 number avoids disturbing real-time workloads,
5359 cancel laziness on that CPU. Use -1 to disable
5369 only printed prior to the stall-warning message
5370 for a given grace period. Disable with a value
5388 warning messages. Disable with a value less
5397 of zero will disable batching. Batching is
5405 disable batching. Batching is always disabled
5413 disable batching. Batching is always disabled
5425 force - Override the decision by the kernel to hide the
5453 Set test-start holdoff period. The purpose of
5462 but the default has already reduced the per-pass
5467 Set number of readers. The default value of -1
5476 Set the read-side critical-section duration,
5480 Specify the read-protection implementation to test.
5483 Shut down the system at the end of the performance
5499 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
5507 reservetop= [X86-32]
5524 See Documentation/power/swsusp-and-swap-files.rst
5539 AMD-based UNRET and IBPB mitigations alone do not stop
5541 sibling threads. For that reason, STIBP is used on pro-
5545 off - no mitigation
5546 auto - automatically select a migitation
5547 auto,nosmt - automatically select a mitigation,
5551 ibpb - On AMD, mitigate short speculation
5556 ibpb,nosmt - Like "ibpb" above but will disable SMT
5560 unret - Force enable untrained return thunks,
5561 only effective on AMD f15h-f17h based
5563 unret,nosmt - Like unret, but will disable SMT when STIBP
5587 ring3mwait=disable
5588 [KNL] Disable ring 3 MONITOR/MWAIT feature on supported
5598 ro [KNL] Mount root device read-only on boot
5601 on Mark read-only kernel memory as read-only (default).
5602 off Leave read-only kernel memory writable for debugging.
5603 full Mark read-only kernel memory and aliases as read-only
5609 debug-uart get routed to the D+ and D- pins of the usb
5615 block/early-lookup.c for details.
5618 system, or "mtd" and "ubi" for mounting from raw flash.
5640 rw [KNL] Mount root device read-write on boot
5668 schedstats= [KNL,X86] Enable or disable scheduled statistics.
5669 Allowed values are enable and disable. This feature
5692 to 10 seconds for built-in smp_call_function()
5699 that requesting even small non-zero numbers of
5706 The default of -1 specifies a number of kthreads
5711 test before initiating CPU-hotplug operations.
5715 CPU-hotplug operations. Specifying zero (which
5716 is the default) disables CPU-hotplug operations.
5720 test after which to shut down the system. The
5721 default of zero avoids shutting down the system.
5722 Non-zero values are useful for automated tests.
5735 preempt_disable() to disable CPU hotplug
5745 "wait" parameter. A value of -1 selects the
5746 default if all other weights are -1. However,
5748 value of -1 will instead select a weight of zero.
5753 non-zero "wait" parameter. See weight_single.
5761 on the system.
5766 non-zero "wait" parameter. See weight_single
5778 non-zero "wait" parameter. See weight_single
5785 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
5786 1 -- enable.
5794 selinux= [SELINUX] Disable or enable SELinux at boot time.
5797 0 -- disable.
5798 1 -- enable.
5801 serialnumber [BUGS=X86-32]
5803 sev=option[,option...] [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
5811 to set it to "all" by meaning -- no limit here.
5817 simeth= [IA-64]
5827 Disable merging of slabs with similar size. May be
5835 unchanged). Debug options disable merging on their
5892 using the csdlock_debug- kernel parameter.
5897 system. By default, let CSD-lock acquisition
5899 for this value provides a 5-minute timeout.
5901 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
5902 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
5903 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
5904 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
5905 smsc-ircc2.ircc_irq= [HW] IRQ line
5906 smsc-ircc2.ircc_dma= [HW] DMA channel
5907 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
5917 Default: -1 (no limit)
5920 [KNL] Should the soft-lockup detector generate panics.
5923 A value of 1 instructs the soft-lockup detector
5924 to panic the machine when a soft-lockup occurs. It is
5927 respective build-time switch to that functionality.
5930 [KNL] Should the soft-lockup detector generate
5935 See Documentation/admin-guide/laptops/sonypi.rst
5942 on - (default) Enable the HW or SW mitigation
5944 off - Disable the mitigation.
5951 on - unconditionally enable, implies
5953 off - unconditionally disable, implies
5955 auto - kernel detects whether your CPU model is
5967 Selecting 'off' will disable both the kernel and
5972 retpoline - replace indirect branches
5973 retpoline,generic - Retpolines
5974 retpoline,lfence - LFENCE; indirect branch
5975 retpoline,amd - alias for retpoline,lfence
5976 eibrs - Enhanced/Auto IBRS
5977 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
5978 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
5979 ibrs - use IBRS to protect kernel
5989 on - Unconditionally enable mitigations. Is
5992 off - Unconditionally disable mitigations. Is
5995 prctl - Indirect branch speculation is enabled,
6001 - Like "prctl" above, but only STIBP is
6007 - Same as "prctl" above, but all seccomp
6012 - Like "seccomp" above, but only STIBP is
6017 auto - Kernel selects the mitigation depending on
6028 off - Disable mitigation
6029 microcode - Enable microcode mitigation only
6030 safe-ret - Enable sw-only safe RET mitigation (default)
6031 ibpb - Enable mitigation by issuing IBPB on
6033 ibpb-vmexit - Issue IBPB only on VMEXIT
6034 (cloud-specific mitigation)
6037 [HW] Control Speculative Store Bypass (SSB) Disable mitigation
6059 on - Unconditionally disable Speculative Store Bypass
6060 off - Unconditionally enable Speculative Store Bypass
6061 auto - Kernel detects whether the CPU model contains an
6067 prctl - Control Speculative Store Bypass per thread
6071 seccomp - Same as "prctl" above, but all seccomp threads
6072 will disable SSB unless they explicitly opt out.
6079 on,auto - On Power8 and Power9 insert a store-forwarding
6083 off - No action.
6102 off - not enabled
6104 warn - the kernel will emit rate-limited warnings
6112 fatal - the kernel will send SIGBUS to applications
6117 ratelimit:N -
6118 Set system wide rate limit to N bus locks
6137 Certain CPUs are vulnerable to an MDS-like
6150 off: Disable mitigation and remove
6155 large system, such that srcu_struct structures
6157 This kernel-boot parameter defaults to 128,
6158 but takes effect only when the low-order four
6175 instead of the compile-time CONFIG_NR_CPUS.
6179 grace-period sequence counter wrap for the
6180 srcu_data structure's ->srcu_gp_seq_needed field.
6191 expediting. Set to zero to disable automatic
6195 Specifies the number of no-delay instances
6202 Specifies the per-grace-period phase, number of
6203 non-sleeping polls of readers. Beyond this limit,
6209 Specifies number of microseconds of non-sleeping
6210 delay between each non-sleeping poll of readers.
6213 Specifies the number of update-side contention
6218 set for contention-based conversions to occur.
6221 Speculative Store Bypass Disable control
6228 force-on: Unconditionally enable mitigation for
6230 force-off: Unconditionally disable mitigation for
6246 disable the stack depot thereby saving the static memory
6253 stacktrace_filter=[function-list]
6255 will trace at boot up. function-list is a comma-separated
6263 Set the STI (builtin display/keyboard on the HP-PARISC
6265 as the initial boot-console.
6277 Enable or disable strict sigaltstack size checks
6325 to global on non-NUMA machines)
6339 mode before resuming the system (see
6348 swiotlb= [ARM,IA-64,PPC,MIPS,X86]
6350 <int> -- Number of I/O TLB slabs
6351 <int> -- Second integer after comma. Number of swiotlb
6354 force -- force using of bounce buffers even if they
6356 noforce -- Never use bounce buffers (for debugging)
6371 Ignore sysrq setting - this boot parameter will
6379 cache size. See Documentation/networking/ip-sysctl.rst
6386 Specify "mem" (for Suspend-to-RAM) or "standby" (for
6388 as the system sleep state during system startup with
6390 The system is woken from this state using a
6391 wakeup-capable RTC alarm.
6397 -1: disable all active trip points in all thermal zones
6401 -1: disable all critical trip points in all thermal zones
6405 1: disable ACPI thermal control
6408 -1: disable all passive trip points
6414 <deci-seconds>: poll all this frequency
6436 Prevent the CPU-hotplug component of torturing
6440 Dump the ftrace buffer at torture-test shutdown,
6444 with rotating-rust storage.
6449 disables verbose-printk() sleeping.
6452 Duration of each verbose-printk() sleep in jiffies.
6470 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
6475 where the system hangs or reboots and does not give the
6492 the system to live lock.
6498 make the system inoperable.
6508 local - Use the per CPU time stamp counter
6512 global - Event time stamps are synchronize across
6515 counter - Simple counting of events (1, 2, ..)
6519 uptime - Use jiffies as the time stamp.
6520 perf - Use the same clock that perf uses.
6521 mono - Use ktime_get_mono_fast_ns() for time stamps.
6522 mono_raw - Use ktime_get_raw_fast_ns() for time
6524 boot - Use ktime_get_boot_fast_ns() for time stamps.
6528 trace_event=[event-list]
6530 to facilitate early boot debugging. The event-list is a
6531 comma-separated list of trace events to enable. See
6534 trace_instance=[instance-info]
6545 Note, the "<system*>:" portion is optional if the event is
6552 event, and all events under the "initcall" system.
6554 trace_options=[option-list]
6555 [FTRACE] Enable or disable tracer options at boot.
6556 The option-list is a comma delimited list of options
6570 trace_trigger=[trigger-list]
6590 [FTRACE] enable this option to disable tracing when a
6605 Can be used to control the default behavior of the system
6607 See Documentation/admin-guide/mm/transhuge.rst
6615 - "tpm"
6616 - "tee"
6617 - "caam"
6627 - "kernel"
6628 - the same value as trusted.source: "tpm" or "tee"
6629 - "default"
6633 tsc= Disable clocksource stability checks for TSC.
6638 high-resolution timer mode on older hardware, and in
6641 Used to run time disable IRQ_TIME_ACCOUNTING on any
6647 [x86] nowatchdog: disable clocksource watchdog. Used
6674 on - Enable TSX on the system. Although there are
6677 several previous speculation-related CVEs, and
6681 off - Disable TSX on the system. (Note that this
6689 auto - Disable TSX if X86_BUG_TAA is present,
6690 otherwise enable TSX on the system.
6694 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
6700 Similar to Micro-architectural Data Sampling (MDS)
6715 full - Enable TAA mitigation on vulnerable CPUs
6718 full,nosmt - Enable TAA mitigation and disable SMT on
6721 vulnerable to cross-thread TAA attacks.
6722 off - Unconditionally disable TAA mitigation
6724 On MDS-affected machines, tsx_async_abort=off can be
6726 are mitigated with the same mechanism so in order to disable
6736 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
6742 See also Documentation/input/devices/joystick-parport.rst
6744 udbg-immortal [PPC] When debugging early kernel crashes that
6750 Set number of hash buckets for UDP/UDP-Lite connections
6752 uhci-hcd.ignore_oc=
6754 Some badly-designed motherboards generate lots of
6763 unwind_debug [X86-64]
6771 (default -1 = authorized (same as 1),
6777 for newly-detected USB devices (default 2). This
6805 [USB] Specifies timeout for the initial 64-byte
6809 usbcore.nousb [USB] Disable the USB subsystem
6812 [USB] A list of quirk entries to augment the built-in
6815 VendorID:ProductID:Flags. The IDs are 4-digit hex
6817 will change the built-in quirk; setting it if it is
6822 a 255-byte read);
6826 Set-Interface requests);
6845 (bInterval-1).
6883 usb-storage.delay_use=
6887 usb-storage.quirks=
6889 override the built-in unusual_devs list. List
6892 and Product ID values (4-digit hex numbers) and
6894 to a common usb-storage quirk flag as follows:
6936 medium is write-protected).
6945 1 - undefined instruction events
6946 2 - system calls
6947 4 - invalid data aborts
6948 8 - SIGSEGV faults
6949 16 - SIGBUS faults
6963 vdso=0: disable VDSO mapping
6965 vdso32= [X86] Control the 32-bit vDSO
6966 vdso32=1: enable 32-bit VDSO
6967 vdso32=0 or vdso32=2: disable 32-bit VDSO
6977 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
6979 vector= [IA-64,SMP]
7011 vga= [BOOT,X86-32] Select a particular video mode
7013 Documentation/admin-guide/svga.rst.
7019 May slow down system boot speed, especially when
7028 - Disable all of the above options
7040 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
7049 vsyscall= [X86-64]
7052 code). Most statically-linked binaries and older
7067 might break your system.
7076 see VGA-softcursor.txt. Default: 2 = underline.
7081 This is a 16-member array composed of values
7082 ranging from 0-255.
7087 This is a 16-member array composed of values
7088 ranging from 0-255.
7093 This is a 16-member array composed of values
7094 ranging from 0-255.
7099 Set system-wide default UTF-8 mode for all tty's.
7100 Default is 1, i.e. UTF-8 mode is enabled for all
7105 Format=<-1|0|1>
7106 Set system-wide default for whether a cursor
7107 is shown on new VTs. Default is -1,
7112 vt.italic= [VT] Default color for italic text; 0-15.
7115 vt.underline= [VT] Default color for underlined text; 0-15.
7119 see Documentation/watchdog/watchdog-parameters.rst
7120 or other driver-specific files in the
7134 Format: <cpu-list>
7148 Per-cpu work items which run for longer than this
7151 them from noticeably delaying other per-cpu work
7160 Per-cpu workqueues are generally preferred because
7162 locality; unfortunately, per-cpu workqueues tend to
7165 Enabling this makes the per-cpu workqueues which
7177 "numa" and "system". Default is "cache". For more
7179 Documentation/core-api/workqueue.rst.
7192 forces round-robin CPU selection to flush out
7200 on - Enable writecombine, use WUC for ioremap_wc()
7201 off - Disable writecombine, use SUC for ioremap_wc()
7203 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
7207 xen_512gb_limit [KNL,X86-64,XEN]
7217 ide-disks -- unplug primary master IDE devices
7218 aux-ide-disks -- unplug non-primary-master IDE devices
7219 nics -- unplug network devices
7220 all -- unplug all emulated devices (NICs and IDE disks)
7221 unnecessary -- unplugging emulated devices is
7224 never -- do not unplug even if version check succeeds
7232 Select whether to always use non-faulting (safe) MSR
7248 [KNL,X86,XEN] Disable the vector callback for Xen
7254 with /sys/devices/system/xen_memory/xen_memory0/scrub_pages.
7257 xen_timer_slop= [X86-64,XEN]
7280 Boolean parameter to disable using fifo event handling
7282 preferred over the 2-level event handling, as it is
7299 xive.store-eoi=off [PPC]
7305 xhci-hcd.quirks [USB,KNL]