Lines Matching +full:int +full:- +full:clock +full:- +full:stable +full:- +full:broken
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
19 Format: <int>
26 If set to vendor, prefer vendor-specific driver
35 64 bit X_* addresses. Some firmware have broken 64
49 Format: <int>
58 Documentation/firmware-guide/acpi/debug.rst for more information about
116 Format: <byte> or <bitmap-list>
119 Disable auto-serialization of AML methods
122 auto-serialization feature.
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
225 For broken nForce2 BIOS resulting in XT-PIC timer.
234 as soon as the kernel's real-mode entry point is called.
253 but some broken systems don't work without it).
259 Use timer override. For some broken Nvidia NF5 boards
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
305 and hot-unplug operations may be restricted.
307 See Documentation/arch/arm64/asymmetric-32bit.rst for more
310 amd_iommu= [HW,X86-64]
313 fullflush - Deprecated, equivalent to iommu.strict=1
314 off - do not initialize any AMD IOMMU found in
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.
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
387 when initialising the APIC and IO-APIC components.
388 For X86-32, this can also be used to specify an APIC
411 0 -- disable.
412 1 -- enable.
415 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
446 Format: <int> (2 = AT (default), 3 = PS/2)
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
470 Format: <int> (must be >=0)
476 0 - Disable the BAU.
477 1 - Enable the BAU.
478 unset - Disable the BAU.
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.
551 inclusive. See arch/mips/include/asm/pgtable-bits.h
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
571 Specifying "pressure" disables per-cgroup pressure
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.
606 numbers X. Note the Linux-specific bits are not necessarily
607 stable over kernel options, but the vendor-specific
623 Prevents the clock framework from automatically gating
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
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.
807 syscall, or to executing "dmesg -S --raw" or to reading
831 disable the cpuidle sub-system
837 disable the cpufreq sub-system
845 [X86] Delay for N microsec between assert and de-assert
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.
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.
890 [KNL, X86-64, ARM64, RISCV] range under 4G. When crashkernel=X,high
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
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
946 Format: <int>
948 self-tests.
950 (no extra messages), setting it to -1 (all bits set)
951 will print _a_lot_ more information - normally only
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
1081 Format: <int>
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
1148 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1158 Broken monitors, graphic adapters, KVMs and EDIDless
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).
1229 the uart clock frequency; if unspecified, it is set
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
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).
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]
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
1672 gcov_persist= [GCOV] When non-zero (default), profiling data for
1682 gpio-mockup.gpio_mockup_ranges
1685 gpio-mockup.gpio_mockup_named_lines
1705 Format: <unsigned int> such that (txsize & ~0x1fffc0) == 0.
1708 Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0.
1717 against bounds-checking flaws in the kernel's
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
1739 corresponding firmware-first mode error processing
1749 during restoration read-only).
1775 hpet= [X86-32,HPET] option to control HPET usage
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.
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
1882 suspend-to-ram transitions, only during s2r
1906 -1 -- never invert brightness
1907 0 -- machine default
1908 1 -- force brightness inversion
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.
2147 could harm performance of some high-throughput
2156 1 to 9 specify maximum depth of C-state.
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]
2207 BIOS x2APIC opt-out request will be ignored
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.
2298 Enables support for pseudo-NMIs in the kernel. This
2304 for it. Intended to get systems with badly broken
2310 interrupt. Intended to get systems with badly broken
2317 [Deprecated - use cpusets instead]
2318 Format: [flag-list,]<cpu-list>
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
2463 subsystem. Note that allocations like PTEs-from-HighMem
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
2614 kvm-arm.mode=
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
2634 kvm-arm.vgic_v3_group0_trap=
2635 [KVM,ARM] Trap guest accesses to GICv3 group-0
2638 kvm-arm.vgic_v3_group1_trap=
2639 [KVM,ARM] Trap guest accesses to GICv3 group-1
2642 kvm-arm.vgic_v3_common_trap=
2646 kvm-arm.vgic_v4_enable=
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
2663 kvm-intel.emulate_invalid_guest_state=
2665 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2671 kvm-intel.flexpriority=
2676 kvm-intel.nested=
2680 kvm-intel.unrestricted_guest=
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
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
2814 Format: <int>
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
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
2952 is useful for hands-off automated testing.
2968 Run the write-side locktorture kthreads at
2969 sched_set_fifo() real-time priority.
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
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
3112 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3126 [ARC,MICROBLAZE] - the limit applies only to low memory,
3129 [ARM64] - only limits memory covered by the linear
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
3264 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3270 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
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.
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
3293 min_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory below this
3300 0 - The attached screen is the 3.5" TFT
3301 1 - The attached screen is the 7" TFT
3302 2 - The VGA Shield is attached (1024x768)
3306 b - Enable backlight. The TFT backlight pin will be
3310 c - Enable the s3c camera interface.
3311 t - Reserved for enabling touchscreen support. The
3315 https://repo.or.cz/w/linux-2.6/mini2440.git
3320 arch-independent options, each of which is an
3321 aggregation of existing arch-specific options.
3349 ssbd=force-off [ARM64]
3362 have other ways of avoiding SMT-based attacks.
3397 full - Enable mitigation on vulnerable CPUs
3399 full,nosmt - Enable mitigation and disable SMT on
3402 off - Unconditionally disable mitigation
3415 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3445 module_blacklist= [KNL] Do not load a comma-separated list of
3459 movablecore= [KNL,X86,IA-64,PPC]
3470 movable_node [KNL] Boot-time switch to make hotplugable memory
3477 Format: <name>,<region-number>,<size>,<offset>
3480 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3488 See arch/arm/mach-s3c/mach-jive.c
3524 something different and driver-specific.
3557 [NFS] enable 64-bit inode numbers.
3558 If zero, the NFS client will fake up a 32-bit inode
3560 of returning the full 64-bit number.
3561 The default is to return 64-bit inode numbers.
3596 [NFS4] Specify an additional fixed unique ident-
3627 driver. A non-zero value sets the minimum interval
3632 server-to-server copies for which this server is
3644 server-to-server copy, knfsd temporarily mounts
3651 See Documentation/admin-guide/nfs/nfsroot.rst.
3653 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3654 See Documentation/admin-guide/nfs/nfsroot.rst.
3657 See Documentation/admin-guide/nfs/nfsroot.rst.
3661 NMI stack-backtrace request.
3670 0 - turn hardlockup detector in nmi_watchdog off
3671 1 - turn hardlockup detector in nmi_watchdog on
3683 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
3687 no4lvl [RISCV] Disable 4-level and 5-level paging modes. Forces
3688 kernel to use 3-level paging instead.
3690 no5lvl [X86-64,RISCV] Disable 5-level paging mode. Forces
3691 kernel to use 4-level paging instead.
3694 caches in the slab allocator. Saves per-node memory,
3731 no_entry_flush [PPC] Don't flush the L1-D cache when entering the kernel.
3733 noexec [IA-64]
3735 noexec32 [X86-64]
3736 This affects only 32-bit executables.
3737 noexec32=on: enable non-executable mappings (default)
3739 noexec32=off: disable non-executable mappings
3750 nofxsr [BUGS=X86-32] Disables x86 floating point extended
3752 legacy floating-point registers on task switch.
3754 nohalt [IA-64] Tells the kernel not to use the power saving
3756 power-consumption. On the positive side, it reduces
3757 interrupt wake-up latency, which may improve performance
3759 real-time systems.
3769 compared. However, if this command-line option is
3810 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
3812 [Deprecated - use intremap=off]
3814 nointroute [IA-64]
3820 noirqdebug [X86-32] Disables the code which attempts to detect and
3825 nojitter [IA-64] Disables jitter checking for ITC timers.
3832 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
3835 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
3837 nolapic [X86-32,APIC] Do not enable or use the local APIC.
3839 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
3841 nomca [IA-64] Disable machine check abort handling
3843 nomce [X86-32] Disable Machine Check Exception
3845 nomfgpt [X86-32] Disable Multi-Function General Purpose
3851 not load if they could possibly displace the pre-
3854 perform display-mode changes or accelerated rendering.
3867 nopcid [X86-64] Disable the PCID cpu feature.
3872 nopti [X86-64]
3888 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
3894 nosbagart [IA-64]
3896 no-scroll [VGA] Disables scrollback.
3897 This is required for the Braillex ib80-piezo Braille
3900 nosgx [X86-64,SGX] Disables Intel SGX kernel support.
3920 nosoftlockup [KNL] Disable the soft-lockup detector.
3925 nospectre_bhb [ARM64] Disable all mitigations for Spectre-BHB (branch
3938 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES] Disable paravirtualized
3945 broken timer IRQ sources.
3948 [PPC] Don't flush the L1-D cache after accessing user data.
3961 no-vmw-sched-clock
3963 clock and use the default one.
3966 soft-lockup and NMI watchdog (hard-lockup).
3970 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
3978 enabling legacy floating-point and sse state.
4004 nptcg= [IA-64] Override max number of concurrent global TLB
4013 n. So during boot up some boot time memory for per-cpu
4014 variables need be pre-allocated for later physical cpu
4029 See Documentation/admin-guide/sysctl/vm.rst for details.
4032 See Documentation/core-api/debugging-via-ohci1394.rst for more
4047 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4051 boundary - index of last SLC block on Flex-OneNAND.
4053 lock - Configure if Flex-OneNAND boundary should be locked.
4067 running on a platform with a direct-mapped memory-side
4073 page_owner= [KNL] Boot-time page_owner enabling option.
4079 page_poison= [KNL] Boot-time parameter changing the state of
4106 See Documentation/admin-guide/tainted-kernels.rst for
4157 Format: <int>
4158 Set to non-zero to probe primary and secondary ISA
4163 Format: <int>
4164 Set to non-zero if a chip is present that snoops speed
4168 Format: <int>
4174 Format: <int>
4180 Format: <int>
4192 Format: <int>
4198 Format: <int>
4204 Format: <int>
4211 Format: <int>
4212 Set to non-zero to probe tertiary and further ISA
4216 Format: <int>
4227 Format: <int>
4228 Set to non-zero to probe QDI controllers. By default
4232 Format: <int>
4233 Set to non-zero to probe Winbond controllers. Use
4240 Format: <int>
4246 pause_on_oops=<int>
4280 bios [X86-32] force use of PCI BIOS, don't access
4282 has a non-standard PCI host bridge.
4283 nobios [X86-32] disallow use of PCI BIOS, only direct
4289 data in IO port 0xCFC, both 32-bit).
4291 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4292 the function, IO port 0xCFA, also 8-bit, sets
4294 through ports 0xC000-0xCFFF).
4301 root domains (aka PCI segments, in ACPI-speak).
4309 disable the use of MSI interrupts system-wide.
4314 primary IO-APIC for bridges that cannot disable
4321 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4345 F0000h-100000h range.
4350 assign-busses [X86] Always assign all PCI bus
4355 some systems with broken BIOSes, notably
4371 <linux-pci@vger.kernel.org>.
4375 a bug to <linux-pci@vger.kernel.org>.
4379 for broken drivers that don't call it.
4383 This might help on some broken boards which
4387 bfsort Sort PCI devices into breadth-first order.
4390 nobfsort Don't sort PCI devices into breadth-first order.
4392 tuning and use the BIOS-configured MPS defaults.
4402 configuration allows peer-to-peer DMA between
4405 that hot-added devices will work.
4420 A PCI-PCI bridge can be specified if resource
4426 for 4096-byte alignment.
4428 end-to-end CRC checking). Only effective if
4459 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4495 dpc-native Use native PCIe service for DPC only. May
4512 Keep all power-domains already enabled by bootloader on,
4529 pirq= [SMP,APIC] Manual mp-table setup
4530 See Documentation/arch/x86/i386/IO-APIC.rst.
4534 See also Documentation/admin-guide/parport.rst.
4553 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4562 { on | off | curr | res | no-curr | no-res }
4602 none - Limited to cond_resched() calls
4603 voluntary - Limited to cond_resched() and might_sleep() calls
4604 full - Any section that isn't explicitly preempt disabled
4607 print-fatal-signals=
4613 coredump - etc.
4616 you might want to try "ulimit -i unlimited".
4628 or lockdep-detected issues (only if lock debug is on).
4637 on - unlimited logging to /dev/kmsg from userspace
4638 off - logging to /dev/kmsg disabled
4639 ratelimit - ratelimit the logging
4650 - 'always': traditional behavior always allows mem overrides.
4651 - 'ptrace': only allow mem overrides for active ptracers.
4652 - 'never': never allow mem overrides.
4656 Limit processor to maximum C-state
4660 Ignore the _CST method to determine C-states,
4667 Param: "schedule" - profile schedule points.
4668 Param: "kvm" - profile VM exits.
4669 Param: <number> - step/bucket size as a power of 2 for
4698 pti= [X86-64] Control Page Table Isolation of user and
4703 on - unconditionally enable
4704 off - unconditionally disable
4705 auto - kernel detects whether your CPU model is
4711 [KNL] Number of legacy pty's. Overwrites compiled-in
4723 See Documentation/admin-guide/md.rst.
4726 See Documentation/admin-guide/blockdev/ramdisk.rst.
4745 cross-syscall address exposures. This is only
4751 ras=option[,option,...] [KNL] RAS-specific options
4757 rcu_nocbs[=cpu-list]
4762 enable the no-callback CPU mode, which prevents
4767 "p" for RCU-preempt, "s" for RCU-sched, and "g"
4771 and real-time workloads. It can also improve
4775 list of CPUs is set to no-callback mode from boot.
4779 no-callback mode from boot but the mode may be
4790 This improves the real-time response for the
4807 RCU grace-period cleanup.
4811 RCU grace-period initialization.
4815 RCU grace-period pre-initialization, that is,
4816 the propagation of recent CPU-hotplug changes up
4820 Set delay from grace-period initialization to
4833 soliciting quiescent-state help from
4845 Set the SCHED_FIFO priority of the RCU per-CPU
4848 and for the RCU grace-period kthreads (rcu_bh,
4850 set, valid values are 1-99 and the default is 1
4851 (the least-favored priority). Otherwise, when
4852 RCU_BOOST is not set, valid values are 0-99 and
4853 the default is zero (non-realtime operation).
4858 On callback-offloaded (rcu_nocbs) CPUs,
4861 use of the ->nocb_bypass list. However, in the
4862 common non-flooded case, RCU queues directly to
4863 the main ->cblist in order to avoid the extra
4864 overhead of the ->nocb_bypass list and its lock.
4866 a single jiffy, RCU pre-queues the callbacks into
4867 the ->nocb_bypass queue. The definition of "too
4876 batch limiting is re-enabled.
4880 RCU's force-quiescent-state scan will aggressively
4888 Set the page-cache refill delay (in milliseconds)
4889 in response to low-memory conditions. The range
4893 Set the shift-right count to use to compute
4894 the callback-invocation batch limit bl from
4901 Please note that this callback-invocation batch
4902 limit applies only to non-offloaded callback
4911 cache-to-cache transfer latencies.
4917 and for NUMA systems with large remote-access
4933 the wakeup overhead on the global grace-period
4935 each group's NOCB grace-period kthread.
4938 Cause the grace-period kthread to get an extra
4940 it should at force-quiescent-state time.
4953 this specifies an rcu_read_unlock()-time delay
4957 of RCU-protected pointers after the relevant
4967 per-CPU rcuc kthreads. Defaults to a non-zero
4977 grace-period primitives such as call_rcu().
4988 grace-period primitives.
4991 Set test-start holdoff period. The purpose of
5009 Test the double-argument variant of kfree_rcu().
5011 rcuscale.kfree_rcu_test_single, both the single-
5012 and double-argument variants are tested.
5015 Test the single-argument variant of kfree_rcu().
5017 rcuscale.kfree_rcu_test_double, both the single-
5018 and double-argument variants are tested.
5032 does not affect the data-collection interval,
5037 Set number of RCU readers. The value -1 selects
5039 "n" less than -1 selects N-n+1, where N is again
5040 the number of CPUs. For example, -2 selects N
5041 (the number of CPUs), -3 selects N+1, and so on.
5042 A value of "n" less than or equal to -N selects
5055 complete. This is useful for hands-off automated
5062 Write-side holdoff between grace periods,
5067 Additional write-side holdoff between grace
5085 for RCU grace-period forward-progress testing
5092 Specify the fraction of a CPU-stall-warning
5093 period to do tight-loop forward-progress testing.
5097 forward-progress tests.
5101 need_resched() during tight-loop forward-progress
5105 Use conditional/asynchronous update-side
5109 Use expedited update-side primitives, if available.
5112 Use normal (non-expedited) asynchronous
5113 update-side primitives, if available.
5116 Use normal (non-expedited) synchronous
5117 update-side primitives, if available. If all
5121 they are all non-zero.
5129 Leak an RCU-protected pointer out of the reader.
5144 Set number of RCU callback-offload togglers.
5149 callback-offload toggling attempts.
5152 Set number of RCU readers. The value -1 selects
5153 N-1, where N is the number of CPUs. A value
5154 "n" less than -1 selects N-n-2, where N is again
5155 the number of CPUs. For example, -2 selects N
5156 (the number of CPUs), -3 selects N+1, and so on.
5159 Enable debug-object double-call_rcu() testing.
5162 Set time (s) after boot for CPU-hotplug testing.
5165 Set time (jiffies) between CPU-hotplug operations,
5166 or zero to disable CPU-hotplug testing.
5169 Set the number of read-then-exit kthreads used
5171 task-exit processing.
5174 The number of times in a given read-then-exit
5175 episode that a set of read-then-exit kthreads
5180 read-then-exit testing episodes.
5183 Set task-shuffle interval (s). Shuffling tasks
5184 allows some CPUs to go into dyntick-idle mode
5189 is useful for hands-off automated testing.
5198 any other stall-related activity. Note that
5204 in scheduling-while-atomic splats.
5217 grace-period kthread to test RCU CPU stall
5243 Test RCU's dyntick-idle handling. See also the
5292 Use expedited grace-period primitives, for
5296 real-time latency, and degrade energy efficiency.
5300 Use only normal grace-period primitives,
5303 real-time latency, CPU utilization, and
5305 increased grace-period latency. This parameter
5312 only normal grace-period primitives. No effect
5318 post-boot attempt at an expedited RCU grace
5319 period to instead use normal non-expedited
5320 grace-period processing.
5328 set to the default value of -1.
5331 Set the minimum number of callback-queuing-time
5332 lock-contention events per jiffy required to
5333 cause the RCU Tasks flavors to switch to per-CPU
5336 the default value of -1.
5341 of -1 allows this to be automatically (and
5349 number avoids disturbing real-time workloads,
5354 cancel laziness on that CPU. Use -1 to disable
5364 only printed prior to the stall-warning message
5420 force - Override the decision by the kernel to hide the
5448 Set test-start holdoff period. The purpose of
5457 but the default has already reduced the per-pass
5462 Set number of readers. The default value of -1
5471 Set the read-side critical-section duration,
5475 Specify the read-protection implementation to test.
5494 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
5502 reservetop= [X86-32]
5513 {/dev/<dev> | PARTUUID=<uuid> | <int>:<int> | <hex>}
5519 See Documentation/power/swsusp-and-swap-files.rst
5534 AMD-based UNRET and IBPB mitigations alone do not stop
5536 sibling threads. For that reason, STIBP is used on pro-
5540 off - no mitigation
5541 auto - automatically select a migitation
5542 auto,nosmt - automatically select a mitigation,
5546 ibpb - On AMD, mitigate short speculation
5551 ibpb,nosmt - Like "ibpb" above but will disable SMT
5555 unret - Force enable untrained return thunks,
5556 only effective on AMD f15h-f17h based
5558 unret,nosmt - Like unret, but will disable SMT when STIBP
5593 ro [KNL] Mount root device read-only on boot
5596 on Mark read-only kernel memory as read-only (default).
5597 off Leave read-only kernel memory writable for debugging.
5598 full Mark read-only kernel memory and aliases as read-only
5604 debug-uart get routed to the D+ and D- pins of the usb
5610 block/early-lookup.c for details.
5635 rw [KNL] Mount root device read-write on boot
5687 to 10 seconds for built-in smp_call_function()
5694 that requesting even small non-zero numbers of
5701 The default of -1 specifies a number of kthreads
5706 test before initiating CPU-hotplug operations.
5710 CPU-hotplug operations. Specifying zero (which
5711 is the default) disables CPU-hotplug operations.
5717 Non-zero values are useful for automated tests.
5740 "wait" parameter. A value of -1 selects the
5741 default if all other weights are -1. However,
5743 value of -1 will instead select a weight of zero.
5748 non-zero "wait" parameter. See weight_single.
5761 non-zero "wait" parameter. See weight_single
5773 non-zero "wait" parameter. See weight_single
5780 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
5781 1 -- enable.
5792 0 -- disable.
5793 1 -- enable.
5796 serialnumber [BUGS=X86-32]
5798 sev=option[,option...] [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
5806 to set it to "all" by meaning -- no limit here.
5812 simeth= [IA-64]
5887 using the csdlock_debug- kernel parameter.
5892 system. By default, let CSD-lock acquisition
5894 for this value provides a 5-minute timeout.
5896 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
5897 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
5898 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
5899 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
5900 smsc-ircc2.ircc_irq= [HW] IRQ line
5901 smsc-ircc2.ircc_dma= [HW] DMA channel
5902 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
5912 Default: -1 (no limit)
5915 [KNL] Should the soft-lockup detector generate panics.
5918 A value of 1 instructs the soft-lockup detector
5919 to panic the machine when a soft-lockup occurs. It is
5922 respective build-time switch to that functionality.
5925 [KNL] Should the soft-lockup detector generate
5930 See Documentation/admin-guide/laptops/sonypi.rst
5937 on - (default) Enable the HW or SW mitigation
5939 off - Disable the mitigation.
5946 on - unconditionally enable, implies
5948 off - unconditionally disable, implies
5950 auto - kernel detects whether your CPU model is
5967 retpoline - replace indirect branches
5968 retpoline,generic - Retpolines
5969 retpoline,lfence - LFENCE; indirect branch
5970 retpoline,amd - alias for retpoline,lfence
5971 eibrs - Enhanced/Auto IBRS
5972 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
5973 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
5974 ibrs - use IBRS to protect kernel
5984 on - Unconditionally enable mitigations. Is
5987 off - Unconditionally disable mitigations. Is
5990 prctl - Indirect branch speculation is enabled,
5996 - Like "prctl" above, but only STIBP is
6002 - Same as "prctl" above, but all seccomp
6007 - Like "seccomp" above, but only STIBP is
6012 auto - Kernel selects the mitigation depending on
6023 off - Disable mitigation
6024 microcode - Enable microcode mitigation only
6025 safe-ret - Enable sw-only safe RET mitigation (default)
6026 ibpb - Enable mitigation by issuing IBPB on
6028 ibpb-vmexit - Issue IBPB only on VMEXIT
6029 (cloud-specific mitigation)
6054 on - Unconditionally disable Speculative Store Bypass
6055 off - Unconditionally enable Speculative Store Bypass
6056 auto - Kernel detects whether the CPU model contains an
6062 prctl - Control Speculative Store Bypass per thread
6066 seccomp - Same as "prctl" above, but all seccomp threads
6074 on,auto - On Power8 and Power9 insert a store-forwarding
6078 off - No action.
6097 off - not enabled
6099 warn - the kernel will emit rate-limited warnings
6107 fatal - the kernel will send SIGBUS to applications
6112 ratelimit:N -
6132 Certain CPUs are vulnerable to an MDS-like
6152 This kernel-boot parameter defaults to 128,
6153 but takes effect only when the low-order four
6170 instead of the compile-time CONFIG_NR_CPUS.
6174 grace-period sequence counter wrap for the
6175 srcu_data structure's ->srcu_gp_seq_needed field.
6190 Specifies the number of no-delay instances
6197 Specifies the per-grace-period phase, number of
6198 non-sleeping polls of readers. Beyond this limit,
6204 Specifies number of microseconds of non-sleeping
6205 delay between each non-sleeping poll of readers.
6208 Specifies the number of update-side contention
6213 set for contention-based conversions to occur.
6223 force-on: Unconditionally enable mitigation for
6225 force-off: Unconditionally disable mitigation for
6248 stacktrace_filter=[function-list]
6250 will trace at boot up. function-list is a comma-separated
6258 Set the STI (builtin display/keyboard on the HP-PARISC
6260 as the initial boot-console.
6320 to global on non-NUMA machines)
6343 swiotlb= [ARM,IA-64,PPC,MIPS,X86]
6344 Format: { <int> [,<int>] | force | noforce }
6345 <int> -- Number of I/O TLB slabs
6346 <int> -- Second integer after comma. Number of swiotlb
6349 force -- force using of bounce buffers even if they
6351 noforce -- Never use bounce buffers (for debugging)
6366 Ignore sysrq setting - this boot parameter will
6374 cache size. See Documentation/networking/ip-sysctl.rst
6381 Specify "mem" (for Suspend-to-RAM) or "standby" (for
6386 wakeup-capable RTC alarm.
6392 -1: disable all active trip points in all thermal zones
6396 -1: disable all critical trip points in all thermal zones
6403 -1: disable all passive trip points
6409 <deci-seconds>: poll all this frequency
6431 Prevent the CPU-hotplug component of torturing
6435 Dump the ftrace buffer at torture-test shutdown,
6439 with rotating-rust storage.
6444 disables verbose-printk() sleeping.
6447 Duration of each verbose-printk() sleep in jiffies.
6465 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
6501 trace_clock= [FTRACE] Set the clock used for tracing events
6503 local - Use the per CPU time stamp counter
6507 global - Event time stamps are synchronize across
6508 CPUs. May be slower than the local clock,
6510 counter - Simple counting of events (1, 2, ..)
6512 infrastructure grabbing the clock more than
6514 uptime - Use jiffies as the time stamp.
6515 perf - Use the same clock that perf uses.
6516 mono - Use ktime_get_mono_fast_ns() for time stamps.
6517 mono_raw - Use ktime_get_raw_fast_ns() for time
6519 boot - Use ktime_get_boot_fast_ns() for time stamps.
6523 trace_event=[event-list]
6525 to facilitate early boot debugging. The event-list is a
6526 comma-separated list of trace events to enable. See
6529 trace_instance=[instance-info]
6549 trace_options=[option-list]
6551 The option-list is a comma delimited list of options
6565 trace_trigger=[trigger-list]
6602 See Documentation/admin-guide/mm/transhuge.rst
6610 - "tpm"
6611 - "tee"
6612 - "caam"
6622 - "kernel"
6623 - the same value as trusted.source: "tpm" or "tee"
6624 - "default"
6633 high-resolution timer mode on older hardware, and in
6661 Format: <unsigned int>
6669 on - Enable TSX on the system. Although there are
6672 several previous speculation-related CVEs, and
6676 off - Disable TSX on the system. (Note that this
6684 auto - Disable TSX if X86_BUG_TAA is present,
6689 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
6695 Similar to Micro-architectural Data Sampling (MDS)
6710 full - Enable TAA mitigation on vulnerable CPUs
6713 full,nosmt - Enable TAA mitigation and disable SMT on
6716 vulnerable to cross-thread TAA attacks.
6717 off - Unconditionally disable TAA mitigation
6719 On MDS-affected machines, tsx_async_abort=off can be
6731 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
6737 See also Documentation/input/devices/joystick-parport.rst
6739 udbg-immortal [PPC] When debugging early kernel crashes that
6745 Set number of hash buckets for UDP/UDP-Lite connections
6747 uhci-hcd.ignore_oc=
6749 Some badly-designed motherboards generate lots of
6758 unwind_debug [X86-64]
6766 (default -1 = authorized (same as 1),
6772 for newly-detected USB devices (default 2). This
6800 [USB] Specifies timeout for the initial 64-byte
6807 [USB] A list of quirk entries to augment the built-in
6810 VendorID:ProductID:Flags. The IDs are 4-digit hex
6812 will change the built-in quirk; setting it if it is
6817 a 255-byte read);
6821 Set-Interface requests);
6840 (bInterval-1).
6878 usb-storage.delay_use=
6882 usb-storage.quirks=
6884 override the built-in unusual_devs list. List
6887 and Product ID values (4-digit hex numbers) and
6889 to a common usb-storage quirk flag as follows:
6931 medium is write-protected).
6938 Format: <int>
6940 1 - undefined instruction events
6941 2 - system calls
6942 4 - invalid data aborts
6943 8 - SIGSEGV faults
6944 16 - SIGBUS faults
6960 vdso32= [X86] Control the 32-bit vDSO
6961 vdso32=1: enable 32-bit VDSO
6962 vdso32=0 or vdso32=2: disable 32-bit VDSO
6972 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
6974 vector= [IA-64,SMP]
7006 vga= [BOOT,X86-32] Select a particular video mode
7008 Documentation/admin-guide/svga.rst.
7023 - Disable all of the above options
7044 vsyscall= [X86-64]
7047 code). Most statically-linked binaries and older
7071 see VGA-softcursor.txt. Default: 2 = underline.
7076 This is a 16-member array composed of values
7077 ranging from 0-255.
7082 This is a 16-member array composed of values
7083 ranging from 0-255.
7088 This is a 16-member array composed of values
7089 ranging from 0-255.
7094 Set system-wide default UTF-8 mode for all tty's.
7095 Default is 1, i.e. UTF-8 mode is enabled for all
7100 Format=<-1|0|1>
7101 Set system-wide default for whether a cursor
7102 is shown on new VTs. Default is -1,
7107 vt.italic= [VT] Default color for italic text; 0-15.
7110 vt.underline= [VT] Default color for underlined text; 0-15.
7114 see Documentation/watchdog/watchdog-parameters.rst
7115 or other driver-specific files in the
7129 Format: <cpu-list>
7143 Per-cpu work items which run for longer than this
7146 them from noticeably delaying other per-cpu work
7155 Per-cpu workqueues are generally preferred because
7157 locality; unfortunately, per-cpu workqueues tend to
7160 Enabling this makes the per-cpu workqueues which
7174 Documentation/core-api/workqueue.rst.
7187 forces round-robin CPU selection to flush out
7188 usages which depend on the now broken guarantee.
7195 on - Enable writecombine, use WUC for ioremap_wc()
7196 off - Disable writecombine, use SUC for ioremap_wc()
7198 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
7202 xen_512gb_limit [KNL,X86-64,XEN]
7212 ide-disks -- unplug primary master IDE devices
7213 aux-ide-disks -- unplug non-primary-master IDE devices
7214 nics -- unplug network devices
7215 all -- unplug all emulated devices (NICs and IDE disks)
7216 unnecessary -- unplugging emulated devices is
7219 never -- do not unplug even if version check succeeds
7227 Select whether to always use non-faulting (safe) MSR
7252 xen_timer_slop= [X86-64,XEN]
7277 preferred over the 2-level event handling, as it is
7294 xive.store-eoi=off [PPC]
7300 xhci-hcd.quirks [USB,KNL]