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
26 If set to vendor, prefer vendor-specific driver
58 Documentation/firmware-guide/acpi/debug.rst for more information about
121 Disable auto-serialization of AML methods
124 auto-serialization feature.
132 Disable installation of static SSDTs at early boot time
142 Ignore the ACPI-based watchdog interface (WDAT) and let
147 on machines running EFI runtime service to boot the
163 acpi_osi=! # disable all built-in OS vendor
165 acpi_osi=!! # enable all built-in OS vendor
227 For broken nForce2 BIOS resulting in XT-PIC timer.
235 as soon as the kernel's real-mode entry point is called.
265 See Documentation/sound/alsa-configuration.rst
272 align_va_addr= [X86-64]
277 CPU-intensive style benchmark, and it can vary highly in
280 32: only for 32-bit processes
281 64: only for 64-bit processes
282 on: enable for both 32- and 64-bit processes
283 off: disable for both 32- and 64-bit processes
286 Allocate the ftrace snapshot buffer on boot up when the
288 and you need to use tracing_snapshot() on boot up, and
292 amd_iommu= [HW,X86-64]
295 fullflush - enable flushing of IO/TLB entries when
299 off - do not initialize any AMD IOMMU found in
301 force_isolation - Force device isolation for all
307 amd_iommu_dump= [HW,X86-64]
313 amd_iommu_intr= [HW,X86-64]
316 legacy - Use legacy interrupt remapping mode.
317 vapic - Use virtual APIC mode, which allows IOMMU
319 This mode requires kvm-amd.avic=1.
333 Power management functions (SPARCstation-4/5 + deriv.)
335 Disable APC CPU standby support. SPARCstation-Fox does
336 not play well with APC CPU idle - disable it if you have
343 when initialising the APIC and IO-APIC components.
344 For X86-32, this can also be used to specify an APIC
364 to set it to "all" by meaning -- no limit here.
373 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
397 audit= [KNL] Enable the audit sub-system
399 0 | off - kernel audit is disabled and can not be
401 unset - kernel audit is initialized but disabled and
403 1 | on - kernel audit is initialized and partially
416 0 - Disable the BAU.
417 1 - Enable the BAU.
418 unset - Disable the BAU.
439 See Documentation/block/cmdline-partition.rst
441 boot_delay= Milliseconds to delay each printk during boot.
450 See Documentation/admin-guide/bootconfig.rst
461 bttv.pll= See Documentation/admin-guide/media/bttv.rst
470 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
489 inclusive. See arch/mips/include/asm/pgtable-bits.h
499 - foo isn't auto-mounted if you mount all cgroups in
501 - foo isn't visible as an individually mountable
518 nosocket -- Disable socket memory accounting.
519 nokmem -- Disable kernel memory accounting.
520 kmem -- Enable kernel memory accounting.
525 0 -- check protection applied by kernel (includes
527 1 -- check protection requested by application.
541 force such clocks to be always-on nor does it reserve
545 information, see Documentation/driver-api/clk.rst.
547 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
564 [X86-32] pit,hpet,tsc;
571 [X86-64] hpet,tsc
577 architected timer so that code using WFE-based polling
600 cma=nn[MG]@[start[MG][-end[MG]]]
611 Sets the size of kernel per-numa memory area for
613 per-numa CMA altogether. And If this option is not
615 With per-numa CMA enabled, DMA users on node nid will
631 com20020= [HW,NET] ARCnet - COM20020 chipset
635 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
639 ARCnet - COM90xx chipset (memory-mapped buffers)
657 See Documentation/admin-guide/serial-console.rst for more
667 Start an early, polled-mode console on the 8250/16550
670 MMIO inter-register address stride is either 8-bit
671 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
675 the h/w is not re-initialized.
696 syscall, or to executing "dmesg -S --raw" or to reading
713 1: enable debugging at boot time
716 disable the cpuidle sub-system
722 disable the cpufreq sub-system
730 [X86] Delay for N microsec between assert and de-assert
732 on every CPU online, such as boot, and resume from suspend.
745 [KNL, X86-64] Select a region under 4G first, and
748 See Documentation/admin-guide/kdump/kdump.rst for further details.
753 start-[end] where start and end are both
755 Documentation/admin-guide/kdump/kdump.rst for an example.
758 [KNL, X86-64] range could be above 4G. Allow kernel
765 [KNL, X86-64] range under 4G. When crashkernel=X,high
770 low memory is needed to make sure DMA buffers for 32-bit
780 [KNL] Disable crypto self-tests
794 See also Documentation/input/devices/joystick-parport.rst
796 ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
798 Documentation/admin-guide/dynamic-debug-howto.rst for
805 boot sequence. If enabled, we use a weak hash instead
812 [KNL] verbose self-tests
815 self-tests.
817 1 will print _a lot_ more information - normally
846 enables the feature at boot time. By default, it is
855 Format: { on, no-mount, off }
857 no-mount:
862 get a -EPERM as result when trying to register files
866 Default value is set in build-time with a kernel configuration.
878 Documentation/admin-guide/mm/hugetlbpage.rst.
921 hardening is enabled for this boot. Hardened
925 against bounds-checking flaws in the kernel's
944 corresponding CPU to be disabled at boot,
981 this option disables the debugging code at boot.
985 entries for DMA-API debugging code. One entry is
986 required per DMA-API allocation. Use this if the
987 DMA-API debugging code disables itself because the
991 With this option the DMA-API debugging driver
992 filter feature can be enabled at boot time. Just
1015 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1026 Generic built-in EDID data sets are used, if one of
1031 available in Documentation/admin-guide/edid.rst. An EDID
1043 Control how the dt_cpu_ftrs device-tree binding is
1053 what data is available or for reverse-engineering.
1057 Enable debug messages at boot time. See
1058 Documentation/admin-guide/dynamic-debug-howto.rst
1075 determined by stdout-path property in device tree's
1080 Start an early, polled-mode console on a Cadence
1091 Start an early, polled-mode console on the 8250/16550
1093 MMIO inter-register address stride is either 8-bit
1094 (mmio) or 32-bit (mmio32 or mmio32be).
1102 Start an early, polled-mode console on a pl011 serial
1106 the driver will use only 32-bit accessors to read/write
1110 Start an early, polled-mode console on a meson serial
1116 Start an early, polled-mode console on an msm serial
1122 Start an early, polled-mode console on an msm serial
1128 Start an early, polled-mode console on a serial port
1134 Start an early, polled-mode console on a serial port
1140 Use RISC-V SBI (Supervisor Binary Interface) for early
1158 Start an early, polled-mode console on a lantiq serial
1172 Start an early, polled-mode, output-only console on the
1177 Start an early, polled-mode console on the
1183 Start an early, polled-mode console on a Qualcomm
1191 coherent non-x86 systems that use system memory for
1257 the boot argument: earlyprintk=vga
1261 very early in the boot process. For early debugging
1273 PCI bridges while in the EFI boot stub.
1275 boot stub, as chunking can cause problems with some
1286 on all PCI bridges while in the EFI boot stub
1302 attribute is added to range 0x100000000-0x180000000 and
1303 0x10a0000000-0x1120000000.
1307 range 0x240000000-0x43fffffff.
1319 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1325 elanfreq= [X86-32]
1333 See Documentation/admin-guide/kdump/kdump.rst for details.
1349 0 -- permissive (log only, no denials).
1350 1 -- enforcing (deny and log).
1374 See also Documentation/fault-injection/.
1378 See Documentation/admin-guide/sysctl/net.rst for
1382 See Documentation/admin-guide/blockdev/floppy.rst.
1385 [IA-64] Avoid check_sal_cache_flush which may hang on
1390 forcepae [X86-32]
1400 boot debugging.
1409 ftrace_filter=[function-list]
1411 tracer at boot up. function-list is a comma separated
1416 ftrace_notrace=[function-list]
1418 function-list. This list can be changed at run time
1422 ftrace_graph_filter=[function-list]
1424 by the function graph tracer at boot up.
1425 function-list is a comma separated list of functions
1429 ftrace_graph_notrace=[function-list]
1431 function-list. This list is a comma separated list of
1446 (suppliers first, then consumers), supplier boot state
1451 off -- Don't create device links from firmware info.
1452 permissive -- Create device links from firmware info
1453 but use it only for ordering boot state clean
1455 on -- Create device links from firmware info and use it
1457 rpm -- Like "on", but also use to order runtime PM.
1463 See also Documentation/input/devices/joystick-parport.rst
1467 gart_fix_e820= [X86-64] disable the fix e820 for K8 GART
1491 gcov_persist= [GCOV] When non-zero (default), profiling data for
1524 gpio-mockup.gpio_mockup_ranges
1529 [KNL] Should the hard-lockup detector generate
1533 hashdist= [KNL,NUMA] Large hashes allocated during boot
1535 for 64-bit NUMA, off otherwise.
1538 hcl= [IA-64] SGI's Hardware Graph compatibility layer
1545 corresponding firmware-first mode error processing
1548 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
1559 hpet= [X86-32,HPET] option to control HPET usage
1576 boot-time allocation of gigantic hugepages is skipped.
1578 hugepages= [HW] Number of HugeTLB pages to allocate at boot.
1584 Documentation/admin-guide/mm/hugetlbpage.rst.
1590 pages of a specific size at boot. The pair
1594 Documentation/admin-guide/mm/hugetlbpage.rst.
1603 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1604 option. The value selected by this boot parameter can
1609 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1618 Do not unregister boot console at start. This is only
1620 between unregistering the boot console and initializing
1632 (disabled by default, and as a pre-condition
1634 i8042.direct [HW] Put keyboard port into non-translated mode
1648 suspend-to-ram transitions, only during s2r
1683 -1 -- never invert brightness
1684 0 -- machine default
1685 1 -- force brightness inversion
1690 ide-core.nodma= [HW] (E)IDE subsystem
1696 ide-generic.probe-mask= [HW] (E)IDE subsystem
1708 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
1719 idle=nomwait: Disable mwait for CPU C-states
1736 legacy only accept legacy-NaN binaries, if supported
1738 2008 only accept 2008-NaN binaries, if supported
1747 'relaxed' straps the emulator for both legacy-NaN and
1748 2008-NaN, whereas 'strict' enables legacy-NaN only on
1757 Ignore loglevel setting - this will print /all/
1821 Formats: { "ima" | "ima-ng" | "ima-sig" }
1822 Default: "ima-ng"
1854 initcall_blacklist= [KNL] Do not execute a comma-separated list of
1855 initcall functions. Useful for debugging built-in
1858 initrd= [BOOT] Specify the location of the initial ramdisk
1879 override in debugfs after boot.
1888 0 -- basic integrity auditing messages. (Default)
1889 1 -- additional integrity auditing messages.
1902 forcedac [X86-64]
1904 for io virtual address below 32-bit forcing dual
1906 than 32-bit addressing. The default is to look
1907 for translation below 32-bit and if not available
1925 could harm performance of some high-throughput
1939 1 to 9 specify maximum depth of C-state.
1949 used along with the hardware-managed P-states (HWP)
1953 in favor of acpi-cpufreq. Forcing the intel_pstate driver
1954 instead of acpi-cpufreq may disable platform features, such
1956 P-States information being indicated to OSPM and therefore
1959 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
1972 Allow per-logical-CPU P-State performance control limits using
1975 intremap= [X86-64, Intel-IOMMU]
1980 BIOS x2APIC opt-out request will be ignored
2004 0 - Lazy mode.
2010 1 - Strict mode (default).
2017 0 - Use IOMMU translation for DMA.
2018 1 - Bypass the IOMMU for DMA.
2019 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2021 io7= [HW] IO7 for Marvel-based Alpha systems
2036 See Documentation/admin-guide/nfs/nfsroot.rst.
2060 Enables support for pseudo-NMIs in the kernel. This
2079 [Deprecated - use cpusets instead]
2080 Format: [flag-list,]<cpu-list>
2111 "number of CPUs in system - 1".
2137 The format of <cpu-list> is described above.
2141 ivrs_ioapic [HW,X86-64]
2142 Provide an override to the IOAPIC-ID<->DEVICE-ID
2146 For example, to map IOAPIC-ID decimal 10 to
2152 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2155 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2159 ivrs_hpet [HW,X86-64]
2160 Provide an override to the HPET-ID<->DEVICE-ID
2164 For example, to map HPET-ID decimal 10 to
2170 * To map HPET-ID decimal 0 to PCI device 00:14.0
2173 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2177 ivrs_acpihid [HW,X86-64]
2178 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2182 For example, to map UART-HID:UID AMD0020:0 to
2188 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2191 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2211 kernelcore= [KNL,X86,IA-64,PPC]
2214 the kernel for non-movable allocations. The requested
2224 subsystem. Note that allocations like PTEs-from-HighMem
2232 for non-movable allocations and remaining memory is used
2243 gdb or control-c on the dbgp connection. When
2244 not using this parameter you use sysrq-g to break into
2249 or a supported polling keyboard driver (non-usb).
2258 If the boot console provides the ability to read
2269 blank and the first boot console that implements
2276 Configure the RouterBoard 532 series on-chip
2279 kmemleak= [KNL] Boot-time kmemleak enable/disable
2285 kprobe_event=[probe-list]
2286 [FTRACE] Add kprobe events and enable at boot time.
2287 The probe-list is a semicolon delimited list of probe
2296 Boot Parameter" section.
2319 auto : Deploy workaround based on the presence of
2322 Default is 'auto'.
2333 kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM.
2336 kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU)
2338 Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
2340 kvm-arm.vgic_v3_group0_trap=
2341 [KVM,ARM] Trap guest accesses to GICv3 group-0
2344 kvm-arm.vgic_v3_group1_trap=
2345 [KVM,ARM] Trap guest accesses to GICv3 group-1
2348 kvm-arm.vgic_v3_common_trap=
2352 kvm-arm.vgic_v4_enable=
2364 kvm-intel.ept= [KVM,Intel] Disable extended page tables
2368 kvm-intel.emulate_invalid_guest_state=
2370 Ignored if kvm-intel.enable_unrestricted_guest=1, as
2376 kvm-intel.flexpriority=
2380 kvm-intel.nested=
2384 kvm-intel.unrestricted_guest=
2389 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2390 CVE-2018-3620.
2401 kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification
2419 boot. Hypervisors will issue a warning
2437 boot. Hypervisors will issue a warning
2449 boot. Hypervisors will issue a warning
2468 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
2474 lapic [X86-32,APIC] Enable the local APIC even if BIOS
2478 value for LAPIC timer one-shot implementation. Default
2513 first fan-out link behind PMP device. It does not
2527 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
2539 hot-unplug link recovery
2576 Set the number of locking read-acquisition kthreads.
2581 Set the number of locking write-acquisition kthreads.
2584 Set time (s) after boot for CPU-hotplug testing.
2587 Set time (s) between CPU-hotplug operations, or
2588 zero to disable CPU-hotplug testing.
2591 Set task-shuffle interval (jiffies). Shuffling
2592 tasks allows some CPUs to go into dyntick-idle
2596 Set time (s) after boot system shutdown. This
2597 is useful for hands-off automated testing.
2630 7 (KERN_DEBUG) debug-level messages
2640 logo.nologo [FB] Disables display of the built-in Linux logo.
2643 kernel boot problems.
2648 lp=auto printer driver. 'lp=reset' (which can be
2655 'parport0'. Specifying 'lp=auto' instead of a
2658 an IEEE 1284-compliant printer is attached; if
2664 time-consuming boot-time autodetection (up to 250 ms per
2666 the correct value for your kernel, boot with normal
2685 machvec= [IA-64] Force the use of a particular machine-vector
2691 Example: machtype=lemote-yeeloong-2f-7inch
2693 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
2706 (loop.max_loop) unconditionally pre-created at init time. The default
2709 devices can be requested on-demand with the
2710 /dev/loop-control interface.
2712 mce [X86-32] Machine Check Exception
2714 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.rst
2717 See Documentation/admin-guide/md.rst.
2724 Control mitigation for the Micro-architectural Data
2739 full - Enable MDS mitigation on vulnerable CPUs
2740 full,nosmt - Enable MDS mitigation and disable
2742 off - Unconditionally disable MDS mitigation
2744 On TAA-affected machines, mds=off can be prevented by
2753 For details see: Documentation/admin-guide/hw-vuln/mds.rst
2755 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
2768 Note that this only takes effects during boot time since
2769 in above case 3, memory may need be hot added after boot
2772 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
2777 per-device physically contiguous DMA buffers.
2785 See Documentation/admin-guide/mm/memory-hotplug.rst.
2810 Example: Exclude memory from 0x18690000-0x1869ffff
2824 memmap=<size>%<offset>-<oldtype>+<newtype>
2826 from <oldtype> to <newtype>. If "-<oldtype>" is left
2841 repeatable BIOS-originated corruption always
2866 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
2874 Refer to Documentation/virt/kvm/amd-memory-encryption.rst
2878 s2idle - Suspend-To-Idle
2879 shallow - Power-On Suspend or equivalent (if supported)
2880 deep - Suspend-To-RAM or equivalent (if supported)
2881 See Documentation/admin-guide/pm/sleep-states.rst.
2884 See Documentation/admin-guide/media/meye.rst.
2886 mfgpt_irq= [IA-32] Specify the IRQ to use for the
2887 Multi-Function General Purpose Timers on AMD Geode
2890 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
2897 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
2904 0 - The attached screen is the 3.5" TFT
2905 1 - The attached screen is the 7" TFT
2906 2 - The VGA Shield is attached (1024x768)
2910 b - Enable backlight. The TFT backlight pin will be
2914 c - Enable the s3c camera interface.
2915 t - Reserved for enabling touchscreen support. The
2919 https://repo.or.cz/w/linux-2.6/mini2440.git
2924 arch-independent options, each of which is an
2925 aggregation of existing arch-specific options.
2947 ssbd=force-off [ARM64]
2955 auto (default)
2960 have other ways of avoiding SMT-based attacks.
2963 auto,nosmt
2971 retbleed=auto,nosmt [X86]
2995 full - Enable mitigation on vulnerable CPUs
2997 full,nosmt - Enable mitigation and disable SMT on
3000 off - Unconditionally disable mitigation
3013 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3021 module_blacklist= [KNL] Do not load a comma-separated list of
3035 movablecore= [KNL,X86,IA-64,PPC]
3046 movable_node [KNL] Boot-time switch to make hotplugable memory
3053 Format: <name>,<region-number>,<size>,<offset>
3056 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3065 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
3069 boundary - index of last SLC block on Flex-OneNAND.
3071 lock - Configure if Flex-OneNAND boundary should be locked.
3076 ARM/S3C2412 JIVE boot control
3078 See arch/arm/mach-s3c2412/mach-jive.c
3106 something different and driver-specific.
3117 See Documentation/admin-guide/nfs/nfsroot.rst.
3119 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3120 See Documentation/admin-guide/nfs/nfsroot.rst.
3123 See Documentation/admin-guide/nfs/nfsroot.rst.
3147 [NFS] enable 64-bit inode numbers.
3148 If zero, the NFS client will fake up a 32-bit inode
3150 of returning the full 64-bit number.
3151 The default is to return 64-bit inode numbers.
3181 [NFS4] Specify an additional fixed unique ident-
3212 driver. A non-zero value sets the minimum interval
3224 NMI stack-backtrace request.
3233 0 - turn hardlockup detector in nmi_watchdog off
3234 1 - turn hardlockup detector in nmi_watchdog on
3251 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
3255 no5lvl [X86-64] Disable 5-level paging mode. Forces
3256 kernel to use 4-level paging instead.
3287 caches in the slab allocator. Saves per-node memory,
3307 nodelayacct [KNL] Disable per-task delay accounting
3309 nodsp [SH] Disable hardware DSP at boot time.
3313 no_entry_flush [PPC] Don't flush the L1-D cache when entering the kernel.
3315 noexec [IA-64]
3318 On X86-32 available only on PAE configured kernels.
3319 noexec=on: enable non-executable mappings (default)
3320 noexec=off: disable non-executable mappings
3330 noexec32 [X86-64]
3331 This affects only 32-bit executables.
3332 noexec32=on: enable non-executable mappings (default)
3334 noexec32=off: disable non-executable mappings
3337 nofpu [MIPS,SH] Disable hardware FPU at boot time.
3339 nofxsr [BUGS=X86-32] Disables x86 floating point extended
3341 legacy floating-point registers on task switch.
3365 [PPC] Don't flush the L1-D cache after accessing user data.
3369 enabling legacy floating-point and sse state.
3394 nohalt [IA-64] Tells the kernel not to use the power saving
3396 power-consumption. On the positive side, it reduces
3397 interrupt wake-up latency, which may improve performance
3399 real-time systems.
3407 nohz_full= [KNL,BOOT,SMP,ISOL]
3411 whenever possible. The boot CPU will be forced outside
3415 rcu_nocbs= boot parameter.
3419 noirqdebug [X86-32] Disables the code which attempts to detect and
3430 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
3432 [Deprecated - use intremap=off]
3434 nointroute [IA-64]
3438 nojitter [IA-64] Disables jitter checking for ITC timers.
3440 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
3442 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
3445 no-vmw-sched-clock
3449 no-steal-acc [X86,PV_OPS,ARM64] Disable paravirtualized steal time
3453 nolapic [X86-32,APIC] Do not enable or use the local APIC.
3455 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
3460 nomca [IA-64] Disable machine check abort handling
3462 nomce [X86-32] Disable Machine Check Exception
3464 nomfgpt [X86-32] Disable Multi-Function General Purpose
3476 nopcid [X86-64] Disable the PCID cpu feature.
3481 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
3492 no-scroll [VGA] Disables scrollback.
3493 This is required for the Braillex ib80-piezo Braille
3496 nosbagart [IA-64]
3498 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
3503 nosoftlockup [KNL] Disable the soft-lockup detector.
3508 soft-lockup and NMI watchdog (hard-lockup).
3512 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
3537 nptcg= [IA-64] Override max number of concurrent global TLB
3546 n. So during boot up some boot time memory for per-cpu
3547 variables need be pre-allocated for later physical cpu
3555 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
3557 This can be set from sysctl after boot.
3558 See Documentation/admin-guide/sysctl/vm.rst for details.
3561 See Documentation/core-api/debugging-via-ohci1394.rst for more
3600 running on a platform with a direct-mapped memory-side
3606 page_owner= [KNL] Boot-time page_owner enabling option.
3612 page_poison= [KNL] Boot-time parameter changing the state of
3642 See Documentation/admin-guide/tainted-kernels.rst for
3650 Run kdump after running panic-notifiers and dumping
3665 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
3666 Use 'auto' to force the driver to use any
3671 should be numbers, or 'auto' (for using detected
3695 See also Documentation/admin-guide/blockdev/paride.rst.
3724 bios [X86-32] force use of PCI BIOS, don't access
3726 has a non-standard PCI host bridge.
3727 nobios [X86-32] disallow use of PCI BIOS, only direct
3733 data in IO port 0xCFC, both 32-bit).
3735 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
3736 the function, IO port 0xCFA, also 8-bit, sets
3738 through ports 0xC000-0xCFFF).
3742 enabled, this kernel boot option can be used to
3745 root domains (aka PCI segments, in ACPI-speak).
3752 enabled, this kernel boot option can be used to
3753 disable the use of MSI interrupts system-wide.
3754 noioapicquirk [APIC] Disable all boot interrupt quirks.
3755 Safety option to keep boot IRQs enabled. This
3757 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
3758 primary IO-APIC for bridges that cannot disable
3759 boot IRQs. This fixes a source of spurious IRQs
3762 boot IRQ equivalent of an IRQ that connects to
3763 a chipset where boot IRQs cannot be disabled.
3765 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
3789 F0000h-100000h range.
3794 assign-busses [X86] Always assign all PCI bus
3822 bfsort Sort PCI devices into breadth-first order.
3825 nobfsort Don't sort PCI devices into breadth-first order.
3827 tuning and use the BIOS-configured MPS defaults.
3837 configuration allows peer-to-peer DMA between
3840 that hot-added devices will work.
3855 A PCI-PCI bridge can be specified if resource
3861 for 4096-byte alignment.
3863 end-to-end CRC checking).
3892 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
3928 dpc-native Use native PCIe service for DPC only. May
3945 Keep all power-domains already enabled by bootloader on,
3951 See Documentation/admin-guide/blockdev/paride.rst.
3954 boot time.
3966 See Documentation/admin-guide/blockdev/paride.rst.
3969 See Documentation/admin-guide/blockdev/paride.rst.
3971 pirq= [SMP,APIC] Manual mp-table setup
3972 See Documentation/x86/i386/IO-APIC.rst.
3976 See also Documentation/admin-guide/parport.rst.
3983 Enable suspend/resume debug messages during boot up.
3987 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
3996 { on | off | curr | res | no-curr | no-res }
4034 print-fatal-signals=
4040 coredump - etc.
4043 you might want to try "ulimit -i unlimited".
4055 on - unlimited logging to /dev/kmsg from userspace
4056 off - logging to /dev/kmsg disabled
4057 ratelimit - ratelimit the logging
4064 Limit processor to maximum C-state
4068 Ignore the _CST method to determine C-states,
4075 Param: "schedule" - profile schedule points.
4076 Param: "sleep" - profile D-state sleeping (millisecs).
4078 Param: "kvm" - profile VM exits.
4079 Param: <number> - step/bucket size as a power of 2 for
4109 See Documentation/admin-guide/blockdev/paride.rst.
4111 pti= [X86-64] Control Page Table Isolation of user and
4116 on - unconditionally enable
4117 off - unconditionally disable
4118 auto - kernel detects whether your CPU model is
4121 Not specifying this option is equivalent to pti=auto.
4123 nopti [X86-64]
4127 [KNL] Number of legacy pty's. Overwrites compiled-in
4135 See Documentation/admin-guide/md.rst.
4138 See Documentation/admin-guide/blockdev/ramdisk.rst.
4154 ras=option[,option,...] [KNL] RAS-specific options
4166 the specified list of CPUs to be no-callback CPUs.
4169 purpose, where "x" is "p" for RCU-preempt, and
4170 "s" for RCU-sched, and "N" is the CPU number.
4172 which can be useful for HPC and real-time
4181 This improves the real-time response for the
4193 out at early boot. This is used for diagnostic
4198 RCU grace-period cleanup.
4202 RCU grace-period initialization.
4206 RCU grace-period pre-initialization, that is,
4207 the propagation of recent CPU-hotplug changes up
4212 per-CPU rcuc kthreads. Defaults to a non-zero
4220 cache-to-cache transfer latencies.
4226 and for NUMA systems with large remote-access
4239 Set delay from grace-period initialization to
4252 soliciting quiescent-state help from
4263 rcutree.kthread_prio= [KNL,BOOT]
4264 Set the SCHED_FIFO priority of the RCU per-CPU
4267 and for the RCU grace-period kthreads (rcu_bh,
4269 set, valid values are 1-99 and the default is 1
4270 (the least-favored priority). Otherwise, when
4271 RCU_BOOST is not set, valid values are 0-99 and
4272 the default is zero (non-realtime operation).
4278 the wakeup overhead on the global grace-period
4280 each group's NOCB grace-period kthread.
4288 batch limiting is re-enabled.
4292 RCU's force-quiescent-state scan will aggressively
4296 on rcutree.qhimark at boot time and to zero to
4310 Cause the grace-period kthread to get an extra
4312 it should at force-quiescent-state time.
4318 this specifies an rcu_read_unlock()-time delay
4322 of RCU-protected pointers after the relevant
4332 grace-period primitives such as call_rcu().
4343 grace-period primitives.
4346 Set test-start holdoff period. The purpose of
4348 test until boot completes in order to avoid
4365 Set number of RCU readers. The value -1 selects
4367 "n" less than -1 selects N-n+1, where N is again
4368 the number of CPUs. For example, -2 selects N
4369 (the number of CPUs), -3 selects N+1, and so on.
4370 A value of "n" less than or equal to -N selects
4383 complete. This is useful for hands-off automated
4390 Write-side holdoff between grace periods,
4407 Enable RCU grace-period forward-progress testing
4411 Specify the fraction of a CPU-stall-warning
4412 period to do tight-loop forward-progress testing.
4416 forward-progress tests.
4420 need_resched() during tight-loop forward-progress
4424 Use conditional/asynchronous update-side
4428 Use expedited update-side primitives, if available.
4431 Use normal (non-expedited) asynchronous
4432 update-side primitives, if available.
4435 Use normal (non-expedited) synchronous
4436 update-side primitives, if available. If all
4440 they are all non-zero.
4448 Leak an RCU-protected pointer out of the reader.
4463 Set number of RCU readers. The value -1 selects
4464 N-1, where N is the number of CPUs. A value
4465 "n" less than -1 selects N-n-2, where N is again
4466 the number of CPUs. For example, -2 selects N
4467 (the number of CPUs), -3 selects N+1, and so on.
4470 Enable debug-object double-call_rcu() testing.
4473 Set time (s) after boot for CPU-hotplug testing.
4476 Set time (jiffies) between CPU-hotplug operations,
4477 or zero to disable CPU-hotplug testing.
4480 Set the number of read-then-exit kthreads used
4482 task-exit processing.
4485 The number of times in a given read-then-exit
4486 episode that a set of read-then-exit kthreads
4491 read-then-exit testing episodes.
4494 Set task-shuffle interval (s). Shuffling tasks
4495 allows some CPUs to go into dyntick-idle mode
4499 Set time (s) after boot system shutdown. This
4500 is useful for hands-off automated testing.
4509 to any other stall-related activity.
4512 Time to wait (s) after boot before inducing stall.
4519 grace-period kthread to test RCU CPU stall
4545 Test RCU's dyntick-idle handling. See also the
4564 during early boot, that is, during the time
4571 Use expedited grace-period primitives, for
4575 real-time latency, and degrade energy efficiency.
4579 Use only normal grace-period primitives,
4582 real-time latency, CPU utilization, and
4584 increased grace-period latency. This parameter
4589 Once boot has completed (that is, after
4591 only normal grace-period primitives. No effect
4598 number avoids disturbing real-time workloads,
4607 Run the RCU early boot self tests
4615 force - Override the decision by the kernel to hide the
4643 Set test-start holdoff period. The purpose of
4645 test until boot completes in order to avoid
4652 but the default has already reduced the per-pass
4657 Set number of readers. The default value of -1
4666 Set the read-side critical-section duration,
4670 Specify the read-protection implementation to test.
4683 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
4691 reservetop= [X86-32]
4713 See Documentation/power/swsusp-and-swap-files.rst
4724 present during boot.
4729 during restoration read-only).
4737 AMD-based UNRET and IBPB mitigations alone do not stop
4739 sibling threads. For that reason, STIBP is used on pro-
4743 off - no mitigation
4744 auto - automatically select a migitation
4745 auto,nosmt - automatically select a mitigation,
4749 ibpb - On AMD, mitigate short speculation
4754 ibpb,nosmt - Like "ibpb" above but will disable SMT
4758 unret - Force enable untrained return thunks,
4759 only effective on AMD f15h-f17h based
4761 unret,nosmt - Like unret, but will disable SMT when STIBP
4765 Selecting 'auto' will choose a mitigation method at run
4768 Not specifying this option is equivalent to retbleed=auto.
4789 ro [KNL] Mount root device read-only on boot
4792 on Mark read-only kernel memory as read-only (default).
4793 off Leave read-only kernel memory writable for debugging.
4798 debug-uart get routed to the D+ and D- pins of the usb
4820 rw [KNL] Mount root device read-write on boot
4862 to 10 seconds for built-in smp_call_function()
4869 that requesting even small non-zero numbers of
4876 The default of -1 specifies a number of kthreads
4881 test before initiating CPU-hotplug operations.
4885 CPU-hotplug operations. Specifying zero (which
4886 is the default) disables CPU-hotplug operations.
4892 Non-zero values are useful for automated tests.
4915 "wait" parameter. A value of -1 selects the
4916 default if all other weights are -1. However,
4918 value of -1 will instead select a weight of zero.
4923 non-zero "wait" parameter. See weight_single.
4936 non-zero "wait" parameter. See weight_single
4948 non-zero "wait" parameter. See weight_single
4955 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
4956 1 -- enable.
4961 enable at boot. This has been deprecated by the
4964 selinux= [SELINUX] Disable or enable SELinux at boot time.
4967 0 -- disable.
4968 1 -- enable.
4971 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
4974 0 -- disable.
4975 1 -- enable.
4978 serialnumber [BUGS=X86-32]
4983 simeth= [IA-64]
5017 memory cgroup sub-caches. 1 to enable, 0 to disable.
5050 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
5051 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
5052 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
5053 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
5054 smsc-ircc2.ircc_irq= [HW] IRQ line
5055 smsc-ircc2.ircc_dma= [HW] DMA channel
5056 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
5066 Default: -1 (no limit)
5069 [KNL] Should the soft-lockup detector generate panics.
5072 A value of 1 instructs the soft-lockup detector
5073 to panic the machine when a soft-lockup occurs. It is
5076 respective build-time switch to that functionality.
5079 [KNL] Should the soft-lockup detector generate
5084 See Documentation/admin-guide/laptops/sonypi.rst
5091 on - unconditionally enable, implies
5093 off - unconditionally disable, implies
5095 auto - kernel detects whether your CPU model is
5098 Selecting 'on' will, and 'auto' may, choose a
5112 retpoline - replace indirect branches
5113 retpoline,generic - Retpolines
5114 retpoline,lfence - LFENCE; indirect branch
5115 retpoline,amd - alias for retpoline,lfence
5116 eibrs - Enhanced/Auto IBRS
5117 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
5118 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
5119 ibrs - use IBRS to protect kernel
5122 spectre_v2=auto.
5129 on - Unconditionally enable mitigations. Is
5132 off - Unconditionally disable mitigations. Is
5135 prctl - Indirect branch speculation is enabled,
5141 - Like "prctl" above, but only STIBP is
5147 - Same as "prctl" above, but all seccomp
5152 - Like "seccomp" above, but only STIBP is
5157 auto - Kernel selects the mitigation depending on
5164 spectre_v2_user=auto.
5169 off - Disable mitigation
5170 microcode - Enable microcode mitigation only
5171 safe-ret - Enable sw-only safe RET mitigation (default)
5172 ibpb - Enable mitigation by issuing IBPB on
5174 ibpb-vmexit - Issue IBPB only on VMEXIT
5175 (cloud-specific mitigation)
5200 on - Unconditionally disable Speculative Store Bypass
5201 off - Unconditionally enable Speculative Store Bypass
5202 auto - Kernel detects whether the CPU model contains an
5208 prctl - Control Speculative Store Bypass per thread
5212 seccomp - Same as "prctl" above, but all seccomp threads
5220 on,auto - On Power8 and Power9 insert a store-forwarding
5224 off - No action.
5227 spec_store_bypass_disable=auto.
5241 off - not enabled
5243 warn - the kernel will emit rate limited warnings
5248 fatal - the kernel will send SIGBUS to applications
5260 Certain CPUs are vulnerable to an MDS-like
5278 grace-period sequence counter wrap for the
5279 srcu_data structure's ->srcu_gp_seq_needed field.
5301 force-on: Unconditionally enable mitigation for
5303 force-off: Unconditionally disable mitigation for
5318 Enabled the stack tracer on boot up.
5320 stacktrace_filter=[function-list]
5322 will trace at boot up. function-list is a comma separated
5330 Set the STI (builtin display/keyboard on the HP-PARISC
5332 as the initial boot-console.
5368 auto the server chooses an appropriate mode
5373 to global on non-NUMA machines)
5399 it if 0 is given (See Documentation/admin-guide/cgroup-v1/memory.rst)
5401 swiotlb= [ARM,IA-64,PPC,MIPS,X86]
5403 <int> -- Number of I/O TLB slabs
5404 force -- force using of bounce buffers even if they
5406 noforce -- Never use bounce buffers (for debugging)
5430 Ignore sysrq setting - this boot parameter will
5438 cache size. See Documentation/networking/ip-sysctl.rst
5444 Specify "mem" (for Suspend-to-RAM) or "standby" (for
5449 wakeup-capable RTC alarm.
5455 -1: disable all active trip points in all thermal zones
5459 -1: disable all critical trip points in all thermal zones
5470 -1: disable all passive trip points
5476 <deci-seconds>: poll all this frequency
5498 Prevent the CPU-hotplug component of torturing
5502 Dump the ftrace buffer at torture-test shutdown,
5506 with rotating-rust storage.
5522 trace_event=[event-list]
5524 to facilitate early boot debugging. The event-list is a
5528 trace_options=[option-list]
5529 [FTRACE] Enable or disable tracer options at boot.
5530 The option-list is a comma delimited list of options
5546 tracing ring buffer. This is useful for early boot up
5580 See Documentation/admin-guide/mm/transhuge.rst
5588 high-resolution timer mode on older hardware, and in
5614 on - Enable TSX on the system. Although there are
5617 several previous speculation-related CVEs, and
5621 off - Disable TSX on the system. (Note that this
5629 auto - Disable TSX if X86_BUG_TAA is present,
5634 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
5640 Similar to Micro-architectural Data Sampling (MDS)
5655 full - Enable TAA mitigation on vulnerable CPUs
5658 full,nosmt - Enable TAA mitigation and disable SMT on
5661 vulnerable to cross-thread TAA attacks.
5662 off - Unconditionally disable TAA mitigation
5664 On MDS-affected machines, tsx_async_abort=off can be
5676 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
5682 See also Documentation/input/devices/joystick-parport.rst
5684 udbg-immortal [PPC] When debugging early kernel crashes that
5686 console driver takes over, this boot options might
5690 Set number of hash buckets for UDP/UDP-Lite connections
5692 uhci-hcd.ignore_oc=
5694 Some badly-designed motherboards generate lots of
5705 (default -1 = authorized except for wireless USB,
5711 for newly-detected USB devices (default 2). This
5739 [USB] Specifies timeout for the initial 64-byte
5746 [USB] A list of quirk entries to augment the built-in
5749 VendorID:ProductID:Flags. The IDs are 4-digit hex
5751 will change the built-in quirk; setting it if it is
5756 a 255-byte read);
5760 Set-Interface requests);
5779 (bInterval-1).
5814 usb-storage.delay_use=
5818 usb-storage.quirks=
5820 override the built-in unusual_devs list. List
5823 and Product ID values (4-digit hex numbers) and
5825 to a common usb-storage quirk flag as follows:
5867 medium is write-protected).
5876 1 - undefined instruction events
5877 2 - system calls
5878 4 - invalid data aborts
5879 8 - SIGSEGV faults
5880 16 - SIGBUS faults
5896 vdso32= [X86] Control the 32-bit vDSO
5897 vdso32=1: enable 32-bit VDSO
5898 vdso32=0 or vdso32=2: disable 32-bit VDSO
5908 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
5910 vector= [IA-64,SMP]
5941 vga= [BOOT,X86-32] Select a particular video mode
5942 See Documentation/x86/boot.rst and
5943 Documentation/admin-guide/svga.rst.
5945 This is actually a boot loader parameter; the value is
5949 May slow down system boot speed, especially when
5958 - Disable all of the above options
5960 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
5979 vsyscall= [X86-64]
5982 code). Most statically-linked binaries and older
6006 see VGA-softcursor.txt. Default: 2 = underline.
6011 This is a 16-member array composed of values
6012 ranging from 0-255.
6017 This is a 16-member array composed of values
6018 ranging from 0-255.
6023 This is a 16-member array composed of values
6024 ranging from 0-255.
6029 Set system-wide default UTF-8 mode for all tty's.
6030 Default is 1, i.e. UTF-8 mode is enabled for all
6035 Format=<-1|0|1>
6036 Set system-wide default for whether a cursor
6037 is shown on new VTs. Default is -1,
6042 vt.italic= [VT] Default color for italic text; 0-15.
6045 vt.underline= [VT] Default color for underlined text; 0-15.
6049 see Documentation/watchdog/watchdog-parameters.rst
6050 or other driver-specific files in the
6076 that this also can be controlled per-workqueue for
6080 Per-cpu workqueues are generally preferred because
6082 locality; unfortunately, per-cpu workqueues tend to
6085 Enabling this makes the per-cpu workqueues which
6100 forces round-robin CPU selection to flush out
6108 on - Enable writecombine, use WUC for ioremap_wc()
6109 off - Disable writecombine, use SUC for ioremap_wc()
6111 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
6115 x86_intel_mid_timer= [X86-32,APBT]
6121 xen_512gb_limit [KNL,X86-64,XEN]
6131 ide-disks -- unplug primary master IDE devices
6132 aux-ide-disks -- unplug non-primary-master IDE devices
6133 nics -- unplug network devices
6134 all -- unplug all emulated devices (NICs and IDE disks)
6135 unnecessary -- unplugging emulated devices is
6138 never -- do not unplug even if version check succeeds
6165 xen_timer_slop= [X86-64,XEN]
6173 The time (in seconds) to wait before giving up to boot
6190 preferred over the 2-level event handling, as it is
6217 xhci-hcd.quirks [USB,KNL]
6226 early Call xmon as early as possible on boot; xmon