Lines Matching +full:auto +full:- +full:boot
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
119 Disable auto-serialization of AML methods
122 auto-serialization feature.
130 Disable installation of static SSDTs at early boot time
140 Ignore the ACPI-based watchdog interface (WDAT) and let
145 on machines running EFI runtime service to boot the
161 acpi_osi=! # disable all built-in OS vendor
163 acpi_osi=!! # enable all built-in OS vendor
225 For broken nForce2 BIOS resulting in XT-PIC timer.
233 as soon as the kernel's real-mode entry point is called.
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
284 Allocate the ftrace snapshot buffer on boot up when the
286 and you need to use tracing_snapshot() on boot up, and
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
414 0 - Disable the BAU.
415 1 - Enable the BAU.
416 unset - Disable the BAU.
437 See Documentation/block/cmdline-partition.txt
439 boot_delay= Milliseconds to delay each printk during boot.
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
485 - foo isn't auto-mounted if you mount all cgroups in
487 - foo isn't visible as an individually mountable
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.
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
557 architected timer so that code using WFE-based polling
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
676 1: enable debugging at boot time
679 disable the cpuidle sub-system
682 disable the cpufreq sub-system
685 [X86] Delay for N microsec between assert and de-assert
687 on every CPU online, such as boot, and resume from suspend.
705 start-[end] where start and end are both
722 low memory is needed to make sure DMA buffers for 32-bit
732 [KNL] Disable crypto self-tests
746 See also Documentation/input/devices/joystick-parport.rst
748 ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
750 Documentation/admin-guide/dynamic-debug-howto.rst for
757 boot sequence. If enabled, we use a weak hash instead
764 [KNL] verbose self-tests
767 self-tests.
769 1 will print _a lot_ more information - normally
798 parameter enables the feature at boot time. In
801 it at boot time and the system will work mostly same
842 hardening is enabled for this boot. Hardened
846 against bounds-checking flaws in the kernel's
857 corresponding CPU to be disabled at boot,
888 this option disables the debugging code at boot.
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
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.
940 Enable debug messages at boot time. See
941 Documentation/admin-guide/dynamic-debug-howto.rst
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
1118 the boot argument: earlyprintk=vga
1125 old_map [X86-64]: switch to the old ioremap-based EFI
1126 runtime services mapping. 32-bit still uses this one by
1129 boot stub, as chunking can cause problems with some
1147 attribute is added to range 0x100000000-0x180000000 and
1148 0x10a0000000-0x1120000000.
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.
1194 0 -- permissive (log only, no denials).
1195 1 -- enforcing (deny and log).
1217 See also Documentation/fault-injection/.
1223 [IA-64] Avoid check_sal_cache_flush which may hang on
1228 forcepae [X86-32]
1238 boot debugging.
1247 ftrace_filter=[function-list]
1249 tracer at boot up. function-list is a comma separated
1254 ftrace_notrace=[function-list]
1256 function-list. This list can be changed at run time
1260 ftrace_graph_filter=[function-list]
1262 by the function graph tracer at boot up.
1263 function-list is a comma separated list of functions
1267 ftrace_graph_notrace=[function-list]
1269 function-list. This list is a comma separated list of
1283 See also Documentation/input/devices/joystick-parport.rst
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
1333 hashdist= [KNL,NUMA] Large hashes allocated during boot
1335 for 64-bit NUMA, off otherwise.
1338 hcl= [IA-64] SGI's Hardware Graph compatibility layer
1345 corresponding firmware-first mode error processing
1348 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
1362 hpet= [X86-32,HPET] option to control HPET usage
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.
1397 Do not unregister boot console at start. This is only
1399 between unregistering the boot console and initializing
1411 (disabled by default, and as a pre-condition
1413 i8042.direct [HW] Put keyboard port into non-translated mode
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
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/
1599 Formats: { "ima" | "ima-ng" | "ima-sig" }
1600 Default: "ima-ng"
1632 initcall_blacklist= [KNL] Do not execute a comma-separated list of
1633 initcall functions. Useful for debugging built-in
1636 initrd= [BOOT] Specify the location of the initial ramdisk
1641 override in debugfs after boot.
1650 0 -- basic integrity auditing messages. (Default)
1651 1 -- additional integrity auditing messages.
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.
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]
1738 BIOS x2APIC opt-out request will be ignored
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>
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
1974 auto : Deploy workaround based on the presence of
1977 Default is 'auto'.
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=
2023 kvm-intel.nested=
2027 kvm-intel.unrestricted_guest=
2032 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2033 CVE-2018-3620.
2044 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
2062 boot. Hypervisors will issue a warning
2080 boot. Hypervisors will issue a warning
2092 boot. Hypervisors will issue a warning
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
2155 first fan-out link behind PMP device. It does not
2169 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
2181 hot-unplug link recovery
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
2230 Set time (s) after boot system shutdown. This
2231 is useful for hands-off automated testing.
2264 7 (KERN_DEBUG) debug-level messages
2274 logo.nologo [FB] Disables display of the built-in Linux logo.
2277 kernel boot problems.
2282 lp=auto printer driver. 'lp=reset' (which can be
2289 'parport0'. Specifying 'lp=auto' instead of a
2292 an IEEE 1284-compliant printer is attached; if
2298 time-consuming boot-time autodetection (up to 250 ms per
2300 the correct value for your kernel, boot with normal
2313 machvec= [IA-64] Force the use of a particular machine-vector
2319 Example: machtype=lemote-yeeloong-2f-7inch
2321 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
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
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
2381 For details see: Documentation/admin-guide/hw-vuln/mds.rst
2383 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
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.
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
2485 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
2493 Refer to Documentation/x86/amd-memory-encryption.txt
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
2516 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
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
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.
2558 ssbd=force-off [ARM64]
2571 auto (default)
2576 have other ways of avoiding SMT-based attacks.
2579 auto,nosmt
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.
2656 ARM/S3C2412 JIVE boot control
2658 See arch/arm/mach-s3c2412/mach-jive.c
2686 something different and driver-specific.
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.
2761 [NFS4] Specify an additional fixed unique ident-
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
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.
2849 caches in the slab allocator. Saves per-node memory,
2869 nodelayacct [KNL] Disable per-task delay accounting
2871 nodsp [SH] Disable hardware DSP at boot time.
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
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.
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.
2969 nohz_full= [KNL,BOOT,SMP,ISOL]
2973 whenever possible. The boot CPU will be forced outside
2977 rcu_nocbs= boot parameter.
2981 noirqdebug [X86-32] Disables the code which attempts to detect and
2992 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
2994 [Deprecated - use intremap=off]
2996 nointroute [IA-64]
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
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
3038 nopcid [X86-64] Disable the PCID cpu feature.
3043 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
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.
3065 nosoftlockup [KNL] Disable the soft-lockup detector.
3070 soft-lockup and NMI watchdog (hard-lockup).
3074 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
3099 nptcg= [IA-64] Override max number of concurrent global TLB
3108 n. So during boot up some boot time memory for per-cpu
3109 variables need be pre-allocated for later physical cpu
3117 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
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.
3164 page_poison= [KNL] Boot-time parameter changing the state of
3180 Run kdump after running panic-notifiers and dumping
3195 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
3196 Use 'auto' to force the driver to use any
3201 should be numbers, or 'auto' (for using detected
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
3275 root domains (aka PCI segments, in ACPI-speak).
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.
3285 Safety option to keep boot IRQs enabled. This
3287 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
3288 primary IO-APIC for bridges that cannot disable
3289 boot IRQs. This fixes a source of spurious IRQs
3292 boot IRQ equivalent of an IRQ that connects to
3293 a chipset where boot IRQs cannot be disabled.
3295 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
3319 F0000h-100000h range.
3324 assign-busses [X86] Always assign all PCI bus
3352 bfsort Sort PCI devices into breadth-first order.
3355 nobfsort Don't sort PCI devices into breadth-first order.
3357 tuning and use the BIOS-configured MPS defaults.
3367 configuration allows peer-to-peer DMA between
3370 that hot-added devices will work.
3385 PCI-PCI bridge can be specified, if resource
3392 end-to-end CRC checking).
3414 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
3461 Keep all power-domains already enabled by bootloader on,
3470 boot time.
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 }
3547 print-fatal-signals=
3553 coredump - etc.
3556 you might want to try "ulimit -i unlimited".
3568 on - unlimited logging to /dev/kmsg from userspace
3569 off - logging to /dev/kmsg disabled
3570 ratelimit - ratelimit the logging
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
3627 Not specifying this option is equivalent to pti=auto.
3633 [KNL] Number of legacy pty's. Overwrites compiled-in
3641 See Documentation/admin-guide/md.rst.
3652 ras=option[,option,...] [KNL] RAS-specific options
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"
3669 real-time workloads. It can also improve energy
3677 This improves the real-time response for the
3689 out at early boot. This is used for diagnostic
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
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
3737 rcutree.kthread_prio= [KNL,BOOT]
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.
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
3798 test until boot completes in order to avoid
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
3911 Set time (s) after boot system shutdown. This
3912 is useful for hands-off automated testing.
3919 Time to wait (s) after boot before inducing stall.
3945 Test RCU's dyntick-idle handling. See also the
3961 Use expedited grace-period primitives, for
3965 real-time latency, and degrade energy efficiency.
3969 Use only normal grace-period primitives,
3972 real-time latency, CPU utilization, and
3974 increased grace-period latency. This parameter
3979 Once boot has completed (that is, after
3981 only normal grace-period primitives. No effect
3990 Run the RCU early boot self tests
3993 Run the RCU bh early boot self tests
3996 Run the RCU sched early boot self tests
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
4072 present during boot.
4077 during restoration read-only).
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
4158 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
4159 1 -- enable.
4163 security= [SECURITY] Choose a security module to enable at boot.
4164 If this boot parameter is not specified, only the first
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
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]
4224 memory cgroup sub-caches. 1 to enable, 0 to disable.
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
4305 Selecting 'on' will, and 'auto' may, choose a
4319 retpoline - replace indirect branches
4320 retpoline,generic - google's original retpoline
4321 retpoline,amd - AMD-specific minimal thunk
4324 spectre_v2=auto.
4331 on - Unconditionally enable mitigations. Is
4334 off - Unconditionally disable mitigations. Is
4337 prctl - Indirect branch speculation is enabled,
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
4366 spectre_v2_user=auto.
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
4411 on,auto - On Power8 and Power9 insert a store-forwarding
4415 off - No action.
4418 spec_store_bypass_disable=auto.
4429 Certain CPUs are vulnerable to an MDS-like
4447 grace-period sequence counter wrap for the
4448 srcu_data structure's ->srcu_gp_seq_needed field.
4470 force-on: Unconditionally enable mitigation for
4472 force-off: Unconditionally disable mitigation for
4487 Enabled the stack tracer on boot up.
4489 stacktrace_filter=[function-list]
4491 will trace at boot up. function-list is a comma separated
4499 Set the STI (builtin display/keyboard on the HP-PARISC
4501 as the initial boot-console.
4537 auto the server chooses an appropriate mode
4542 to global on non-NUMA machines)
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)
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
4625 -1: disable all passive trip points
4631 <deci-seconds>: poll all this frequency
4639 Enable the Transcendent memory driver if built-in.
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
4711 tracing ring buffer. This is useful for early boot up
4745 See Documentation/admin-guide/mm/transhuge.rst
4753 high-resolution timer mode on older hardware, and in
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)
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
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
4841 console driver takes over, this boot options might
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
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);
4914 Set-Interface requests);
4933 (bInterval-1).
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
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]
5094 vga= [BOOT,X86-32] Select a particular video mode
5095 See Documentation/x86/boot.txt and
5098 This is actually a boot loader parameter; the value is
5101 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
5120 vsyscall= [X86-64]
5123 code). Most statically-linked binaries and older
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
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
5292 xhci-hcd.quirks [USB,KNL]