Lines Matching +full:boot +full:- +full:enabled
5 avoid prolonged boot times. The lazy option will add
10 at once during boot.
16 force -- enable ACPI if default was off
17 on -- enable ACPI but allow fallback to DT [arm64,riscv64]
18 off -- disable ACPI if default was on
19 noirq -- do not use ACPI for IRQ routing
20 strict -- Be less tolerant of platforms that are not
22 rsdt -- prefer RSDT over (default) XSDT
23 copy_dsdt -- copy DSDT to memory
24 nocmcff -- Disable firmware first mode for corrected
28 nospcr -- disable console in ACPI SPCR table as
45 If set to vendor, prefer vendor-specific driver
69 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
77 Documentation/firmware-guide/acpi/debug.rst for more information about
135 Format: <byte> or <bitmap-list>
138 Disable auto-serialization of AML methods
141 auto-serialization feature.
142 This feature is enabled by default.
149 Disable installation of static SSDTs at early boot time
159 Ignore the ACPI-based watchdog interface (WDAT) and let
164 on machines running EFI runtime service to boot the
180 acpi_osi=! # disable all built-in OS vendor
182 acpi_osi=!! # enable all built-in OS vendor
244 For broken nForce2 BIOS resulting in XT-PIC timer.
253 as soon as the kernel's real-mode entry point is called.
261 s4_hwsig option is enabled.
291 See Documentation/sound/alsa-configuration.rst
298 align_va_addr= [X86-64]
302 machines (where it is enabled by default) for a
303 CPU-intensive style benchmark, and it can vary highly in
306 32: only for 32-bit processes
307 64: only for 64-bit processes
308 on: enable for both 32- and 64-bit processes
309 off: disable for both 32- and 64-bit processes
312 Allocate the ftrace snapshot buffer on boot up when the
314 and you need to use tracing_snapshot() on boot up, and
319 Allow execve() of 32-bit applications and setting of the
321 subset of the CPUs support 32-bit EL0. When this
322 parameter is present, the set of CPUs supporting 32-bit
324 and hot-unplug operations may be restricted.
326 See Documentation/arch/arm64/asymmetric-32bit.rst for more
329 amd_iommu= [HW,X86-64]
332 fullflush - Deprecated, equivalent to iommu.strict=1
333 off - do not initialize any AMD IOMMU found in
335 force_isolation - Force device isolation for all
340 force_enable - Force enable the IOMMU on platforms known
341 to be buggy with IOMMU enabled. Use this
343 pgtbl_v1 - Use v1 page table for DMA-API (Default).
344 pgtbl_v2 - Use v2 page table for DMA-API.
345 irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
346 nohugepages - Limit page-sizes used for v1 page-tables
348 v2_pgsizes_only - Limit page-sizes used for v1 page-tables
352 amd_iommu_dump= [HW,X86-64]
354 for AMD IOMMU. With this option enabled, AMD IOMMU
358 amd_iommu_intr= [HW,X86-64]
361 legacy - Use legacy interrupt remapping mode.
362 vapic - Use virtual APIC mode, which allows IOMMU
364 This mode requires kvm-amd.avic=1.
393 Disable amd-pstate preferred core.
406 Power management functions (SPARCstation-4/5 + deriv.)
408 Disable APC CPU standby support. SPARCstation-Fox does
409 not play well with APC CPU idle - disable it if you have
412 apic [APIC,X86-64] Use IO-APIC. Default.
418 when initialising the APIC and IO-APIC components.
419 For X86-32, this can also be used to specify an APIC
443 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
446 0 -- disable.
447 1 -- enable.
450 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
498 audit= [KNL] Enable the audit sub-system
500 0 | off - kernel audit is disabled and can not be
501 enabled until the next reboot
502 unset - kernel audit is initialized but disabled and
503 will be fully enabled by the userspace auditd.
504 1 | on - kernel audit is initialized and partially
505 enabled, storing at most audit_backlog_limit
506 messages in RAM until it is fully enabled by the
517 0 - Disable the BAU.
518 1 - Enable the BAU.
519 unset - Disable the BAU.
558 See Documentation/block/cmdline-partition.rst
561 Milliseconds to delay each printk during boot.
562 Only works if CONFIG_BOOT_PRINTK_DELAY is enabled,
572 See Documentation/admin-guide/bootconfig.rst
577 bttv.pll= See Documentation/admin-guide/media/bttv.rst
586 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
605 inclusive. See arch/mips/include/asm/pgtable-bits.h
615 - foo isn't auto-mounted if you mount all cgroups in
617 - foo isn't visible as an individually mountable
619 - if foo is an optional feature then the feature is
625 Specifying "pressure" disables per-cgroup pressure
643 nosocket -- Disable socket memory accounting.
644 nokmem -- Disable kernel memory accounting.
645 nobpf -- Disable BPF memory accounting.
650 0 -- check protection applied by kernel (includes
652 1 -- check protection requested by application.
664 numbers X. Note the Linux-specific bits are not necessarily
665 stable over kernel options, but the vendor-specific
682 clocks that have not been explicitly enabled by a Linux
683 device driver but are enabled in hardware at reset or
685 force such clocks to be always-on nor does it reserve
689 information, see Documentation/driver-api/clk.rst.
691 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
708 [X86-32] pit,hpet,tsc;
715 [X86-64] hpet,tsc
721 architected timer so that code using WFE-based polling
735 clocksource-wdtest.holdoff= [KNL]
741 cma=nn[MG]@[start[MG][-end[MG]]]
752 Sets the size of kernel per-numa memory area for
754 per-numa CMA altogether. And If this option is not
756 With per-numa CMA enabled, DMA users on node nid will
767 With numa CMA enabled, DMA users on node nid will
783 com20020= [HW,NET] ARCnet - COM20020 chipset
787 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
791 ARCnet - COM90xx chipset (memory-mapped buffers)
804 This leads to a much faster boot time when a 3270
820 See Documentation/admin-guide/serial-console.rst for more
835 $ ls -d /sys/bus/serial-base/devices/*:*.*/tty/*
836 /sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0
849 Start an early, polled-mode console on the 8250/16550
852 MMIO inter-register address stride is either 8-bit
853 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
857 the h/w is not re-initialized.
884 syscall, or to executing "dmesg -S --raw" or to reading
901 1: enable debugging at boot time
908 disable the cpuidle sub-system
914 disable the cpufreq sub-system
922 [X86,EARLY] Delay for N microsec between assert and de-assert
924 on every CPU online, such as boot, and resume from suspend.
930 Default is enabled if CONFIG_HOTPLUG_PARALLEL=y. Otherwise
943 like Hyper-V, PowerPC (fadump) and AMD SEV-SNP.
951 [KNL, X86-64, ARM64, RISCV, LoongArch] Select a region
954 See Documentation/admin-guide/kdump/kdump.rst for further details.
959 start-[end] where start and end are both
961 Documentation/admin-guide/kdump/kdump.rst for an example.
964 [KNL, X86-64, ARM64, RISCV, LoongArch] range could be
972 [KNL, X86-64, ARM64, RISCV, LoongArch] range under 4G.
978 for 32-bit devices won't run out. Kernel would try to allocate
981 --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
982 --> arm64: 128MiB
983 --> riscv: 128MiB
984 --> loongarch: 128MiB
992 [KNL] Disable crypto self-tests
1000 csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
1015 See also Documentation/input/devices/joystick-parport.rst
1021 boot sequence. If enabled, we use a weak hash instead
1028 [KNL] verbose locking self-tests
1031 self-tests.
1033 (no extra messages), setting it to -1 (all bits set)
1034 will print _a_lot_ more information - normally only
1060 enables the feature at boot time. By default, it is
1069 Format: { on, no-mount, off }
1070 on: All functions are enabled.
1071 no-mount:
1076 get a -EPERM as result when trying to register files
1079 debugfs was not enabled in the kernel at all.
1080 Default value is set in build-time with a kernel configuration.
1092 Documentation/admin-guide/mm/hugetlbpage.rst.
1106 delayacct [KNL] Enable per-task delay accounting
1188 this option disables the debugging code at boot.
1192 entries for DMA-API debugging code. One entry is
1193 required per DMA-API allocation. Use this if the
1194 DMA-API debugging code disables itself because the
1198 With this option the DMA-API debugging driver
1199 filter feature can be enabled at boot time. Just
1218 are enabled. In order to disable RFDS mitigation all
1222 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1247 Control how the dt_cpu_ftrs device-tree binding is
1257 what data is available or for reverse-engineering.
1261 Enable debug messages at boot time. See
1262 Documentation/admin-guide/dynamic-debug-howto.rst
1273 determined by stdout-path property in device tree's
1278 Start an early, polled-mode console on a Cadence
1289 Start an early, polled-mode console on the 8250/16550
1291 MMIO inter-register address stride is either 8-bit
1292 (mmio) or 32-bit (mmio32 or mmio32be).
1302 Start an early, polled-mode console on a pl011 serial
1306 the driver will use only 32-bit accessors to read/write
1315 Start an early, polled-mode console on a meson serial
1321 Start an early, polled-mode console on an msm serial
1327 Start an early, polled-mode console on an msm serial
1333 Start an early, polled-mode console on a serial port
1339 Start an early, polled-mode console on a serial port
1345 Use RISC-V SBI (Supervisor Binary Interface) for early
1363 Start an early, polled-mode console on a lantiq serial
1377 Start an early, polled-mode, output-only console on the
1382 Start an early, polled-mode console on the
1388 Start an early, polled-mode console on a Qualcomm
1396 coherent non-x86 systems that use system memory for
1419 the normal console is initialized. It is not enabled by
1470 PCI bridges while in the EFI boot stub.
1472 boot stub, as chunking can cause problems with some
1483 on all PCI bridges while in the EFI boot stub
1495 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1505 the boot argument: earlyprintk=vga
1509 very early in the boot process. For early debugging
1512 elanfreq= [X86-32]
1520 See Documentation/admin-guide/kdump/kdump.rst for details.
1536 0 -- permissive (log only, no denials).
1537 1 -- enforcing (deny and log).
1556 stages so cover more early boot allocations.
1559 memory initialization is disabled) so the boot process
1570 See also Documentation/fault-injection/.
1574 See Documentation/admin-guide/sysctl/net.rst for
1578 See Documentation/admin-guide/blockdev/floppy.rst.
1580 forcepae [X86-32]
1587 fred= [X86-64]
1596 boot debugging.
1599 [FTRACE] On boot up, a snapshot will be taken of the
1603 boot up that is likely to be overridden by user space
1613 a snapshot at the end of boot up.
1638 ftrace_filter=[function-list]
1640 tracer at boot up. function-list is a comma-separated
1645 ftrace_notrace=[function-list]
1647 function-list. This list can be changed at run time
1651 ftrace_graph_filter=[function-list]
1653 by the function graph tracer at boot up.
1654 function-list is a comma-separated list of functions
1658 ftrace_graph_notrace=[function-list]
1660 function-list. This list is a comma-separated list of
1675 (suppliers first, then consumers), supplier boot state
1680 off -- Don't create device links from firmware info.
1681 permissive -- Create device links from firmware info
1682 but use it only for ordering boot state clean
1684 on -- Create device links from firmware info and use it
1686 rpm -- Like "on", but also use to order runtime PM.
1699 strict -- Default. Continue waiting on consumers to
1701 timeout -- Give up waiting on consumers and call
1711 See also Documentation/input/devices/joystick-parport.rst
1715 gart_fix_e820= [X86-64,EARLY] disable the fix e820 for K8 GART
1741 gcov_persist= [GCOV] When non-zero (default), profiling data for
1751 gpio-mockup.gpio_mockup_ranges
1754 gpio-mockup.gpio_mockup_named_lines
1782 hardening is enabled for this boot. Hardened
1786 against bounds-checking flaws in the kernel's
1792 [KNL] Should the hard-lockup detector generate
1796 hashdist= [KNL,NUMA] Large hashes allocated during boot
1798 for 64-bit NUMA, off otherwise.
1806 corresponding firmware-first mode error processing
1811 present during boot.
1816 during restoration read-only).
1829 highmem=nn[KMG] [KNL,BOOT,EARLY] forces the highmem zone to have an exact
1853 hpet= [X86-32,HPET] option to control HPET usage
1857 force: allow force enabled of undocumented chips (ICH4,
1864 hugepages= [HW] Number of HugeTLB pages to allocate at boot.
1870 number of pages to allocate per-node can be specified.
1871 See also Documentation/admin-guide/mm/hugetlbpage.rst.
1878 pages of a specific size at boot. The pair
1882 Documentation/admin-guide/mm/hugetlbpage.rst.
1892 hugepages using the CMA allocator. If enabled, the
1893 boot-time allocation of gigantic hugepages is skipped.
1897 enabled.
1898 Control if HugeTLB Vmemmap Optimization (HVO) is enabled.
1911 enabled, those vmemmap pages cannot be optimized even if this
1912 feature is enabled. Other vmemmap pages not allocated from
1921 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1922 option. The value selected by this boot parameter can
1927 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1943 Set device-properties for ACPI-enumerated I2C-attached
1944 touchscreen, to e.g. fix coordinates of upside-down
1952 Omit "=<val>" entirely Set a boolean device-property
1953 Unsigned number Set a u32 device-property
1954 Anything else Set a string device-property
1957 i2c_touchscreen_props=GDIX1001:touchscreen-inverted-x:
1958 touchscreen-inverted-y
1960 i2c_touchscreen_props=MSSL1680:touchscreen-size-x=1920:
1961 touchscreen-size-y=1080:touchscreen-inverted-y:
1962 firmware-name=gsl1680-vendor-model.fw:silead,home-button
1967 (disabled by default, and as a pre-condition
1968 requires that i8042.debug=1 be enabled)
1969 i8042.direct [HW] Put keyboard port into non-translated mode
1983 suspend-to-ram transitions, only during s2r
2007 -1 -- never invert brightness
2008 0 -- machine default
2009 1 -- force brightness inversion
2011 ia32_emulation= [X86-64]
2013 When true, allows loading 32-bit programs and executing 32-bit
2015 boot time. When false, unconditionally disables IA32 emulation.
2038 idle=nomwait: Disable mwait for CPU C-states
2066 legacy only accept legacy-NaN binaries, if supported
2068 2008 only accept 2008-NaN binaries, if supported
2079 'relaxed' straps the emulator for both legacy-NaN and
2080 2008-NaN, whereas 'strict' enables legacy-NaN only on
2089 Ignore loglevel setting - this will print /all/
2156 Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" |
2157 "ima-sigv2" }
2158 Default: "ima-ng"
2190 initcall_blacklist= [KNL] Do not execute a comma-separated list of
2191 initcall functions. Useful for debugging built-in
2206 initrd= [BOOT,EARLY] Specify the location of the initial ramdisk
2227 override in debugfs after boot.
2236 0 -- basic integrity auditing messages. (Default)
2237 1 -- additional integrity auditing messages.
2263 Do not force the Intel IOMMU enabled under tboot.
2265 could harm performance of some high-throughput
2267 mapping is enabled.
2274 1 to 9 specify maximum depth of C-state.
2283 algorithms for p-state selection. There are two
2284 P-state selection algorithms provided by
2287 on whether or not the hardware managed P-states
2288 (HWP) feature has been enabled in the processor
2294 used along with the hardware-managed P-states (HWP)
2298 in favor of acpi-cpufreq. Forcing the intel_pstate driver
2299 instead of acpi-cpufreq may disable platform features, such
2301 P-States information being indicated to OSPM and therefore
2304 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
2317 Allow per-logical-CPU P-State performance control limits using
2320 intremap= [X86-64,Intel-IOMMU,EARLY]
2325 BIOS x2APIC opt-out request will be ignored
2368 AMD Gart HW IOMMU-specific options:
2387 Do scatter-gather (SG) merging. Implies "force"
2391 Don't do scatter-gather (SG) merging.
2404 0 - Try to allocate a 32-bit DMA address first, before
2406 1 - Allocate directly from the full usable range,
2408 greater than 32-bit addressing.
2412 0 - Lazy mode.
2418 1 - Strict mode.
2421 unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
2423 legacy driver-specific options takes precedence.
2428 0 - Use IOMMU translation for DMA.
2429 1 - Bypass the IOMMU for DMA.
2430 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2432 io7= [HW] IO7 for Marvel-based Alpha systems
2447 See Documentation/admin-guide/nfs/nfsroot.rst.
2460 Start IPE with success auditing enabled, emitting
2483 Enables support for pseudo-NMIs in the kernel. This
2502 [Deprecated - use cpusets instead]
2503 Format: [flag-list,]<cpu-list>
2536 "number of CPUs in system - 1".
2562 The format of <cpu-list> is described above.
2566 ivrs_ioapic [HW,X86-64]
2567 Provide an override to the IOAPIC-ID<->DEVICE-ID
2571 For example, to map IOAPIC-ID decimal 10 to
2577 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2580 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2584 ivrs_hpet [HW,X86-64]
2585 Provide an override to the HPET-ID<->DEVICE-ID
2589 For example, to map HPET-ID decimal 10 to
2595 * To map HPET-ID decimal 0 to PCI device 00:14.0
2598 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2602 ivrs_acpihid [HW,X86-64]
2603 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2607 For example, to map UART-HID:UID AMD0020:0 to
2613 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2616 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2630 Do not unregister boot console at start. This is only
2632 between unregistering the boot console and initializing
2640 the kernel for non-movable allocations. The requested
2650 subsystem. Note that allocations like PTEs-from-HighMem
2658 for non-movable allocations and remaining memory is used
2669 gdb or control-c on the dbgp connection. When
2670 not using this parameter you use sysrq-g to break into
2675 or a supported polling keyboard driver (non-usb).
2684 If the boot console provides the ability to read
2695 blank and the first boot console that implements
2702 Configure the RouterBoard 532 series on-chip
2705 kmemleak= [KNL,EARLY] Boot-time kmemleak enable/disable
2711 kprobe_event=[probe-list]
2712 [FTRACE] Add kprobe events and enable at boot time.
2713 The probe-list is a semicolon delimited list of probe
2722 Boot Parameter" section.
2726 Default: enabled on cores which need mitigation.
2728 1: force enabled
2731 CONFIG_KUNIT to be set to be fully enabled. The
2734 Default is 1 (enabled)
2743 execution by eliminating the write-protection faults
2753 KVM_DIRTY_LOG_INITIALLY_SET is enabled or disabled. If
2755 split when dirty logging is enabled on that memslot. If
2756 enabled, eager page splitting will be performed during
2765 If enabled, KVM will enable virtualization in hardware
2770 virtualization on-demand when creating and destroying
2778 is that doing so may interfere with using out-of-tree
2794 If the software workaround is enabled for the host,
2805 back to huge pages. If the value is a non-zero N, KVM will
2810 kvm-amd.nested= [KVM,AMD] Control nested virtualization feature in
2811 KVM/SVM. Default is 1 (enabled).
2813 kvm-amd.npt= [KVM,AMD] Control KVM's use of Nested Page Tables,
2814 a.k.a. Two-Dimensional Page Tables. Default is 1
2815 (enabled). Disable by KVM if hardware lacks support
2818 kvm-arm.mode=
2824 nvhe: Standard nVHE-based mode, without support for
2831 nested: VHE-based mode with support for nested
2839 command-line.
2843 kvm-arm.vgic_v3_group0_trap=
2844 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-0
2847 kvm-arm.vgic_v3_group1_trap=
2848 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-1
2851 kvm-arm.vgic_v3_common_trap=
2855 kvm-arm.vgic_v4_enable=
2859 kvm-arm.wfe_trap_policy=
2868 kvm-arm.wfi_trap_policy=
2885 kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables,
2886 a.k.a. Two-Dimensional Page Tables. Default is 1
2887 (enabled). Disable by KVM if hardware lacks support
2890 kvm-intel.emulate_invalid_guest_state=
2892 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2896 Default is 1 (enabled).
2898 kvm-intel.flexpriority=
2900 (TPR shadow). Default is 1 (enabled). Disable by KVM if
2903 kvm-intel.nested=
2905 KVM/VMX. Default is 1 (enabled).
2907 kvm-intel.unrestricted_guest=
2910 is 1 (enabled). Disable by KVM if EPT is disabled or
2913 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2914 CVE-2018-3620.
2925 kvm-intel.vpid= [KVM,Intel] Control KVM's use of Virtual Processor
2927 (enabled). Disable by KVM if hardware lacks support
2945 on - enable the interface for the mitigation
2951 enabled and cannot be disabled.
2961 boot. Hypervisors will issue a warning
2964 i.e. SMT enabled or L1D flush disabled.
2973 Leaves SMT enabled and enables the default
2979 boot. Hypervisors will issue a warning
2982 i.e. SMT enabled or L1D flush disabled.
2991 boot. Hypervisors will issue a warning
2994 i.e. SMT enabled or L1D flush disabled.
3010 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
3016 lapic [X86-32,APIC,EARLY] Enable the local APIC even if BIOS
3020 value for LAPIC timer one-shot implementation. Default
3043 libata.force= [LIBATA] Force configurations. The format is a comma-
3055 first fan-out link behind PMP device. It does not
3069 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
3076 * rstonce: only attempt one reset during hot-unplug
3171 Specify the number of self-propagating call_rcu()
3179 occasional long-duration lock hold time. Defaults
3190 Set the number of locking read-acquisition kthreads.
3195 Set the number of locking write-acquisition kthreads.
3198 Set time (s) after boot for CPU-hotplug testing.
3201 Set time (s) between CPU-hotplug operations, or
3202 zero to disable CPU-hotplug testing.
3205 Do periodic testing of real-time lock priority
3210 non-real-time spinlocks, due to their disabling
3211 of preemption. Note that non-realtime mutexes
3224 Set task-shuffle interval (jiffies). Shuffling
3225 tasks allows some CPUs to go into dyntick-idle
3229 Set time (s) after boot system shutdown. This
3230 is useful for hands-off automated testing.
3249 Run the write-side locktorture kthreads at
3250 sched_set_fifo() real-time priority.
3268 7 (KERN_DEBUG) debug-level messages
3280 logo.nologo [FB] Disables display of the built-in Linux logo.
3283 kernel boot problems.
3298 an IEEE 1284-compliant printer is attached; if
3304 time-consuming boot-time autodetection (up to 250 ms per
3306 the correct value for your kernel, boot with normal
3324 Example: machtype=lemote-yeeloong-2f-7inch
3336 (loop.max_loop) unconditionally pre-created at init time. The default
3339 devices can be requested on-demand with the
3340 /dev/loop-control interface.
3342 mce= [X86-{32,64}]
3379 do not opt-in to Local MCE delivery. Use legacy method
3390 enabled by default.
3393 disable boot machine check logging.
3400 don't overwrite the bios-set CMCI threshold. This boot
3409 force-enable recoverable machine check code paths
3415 See Documentation/admin-guide/md.rst.
3422 Control mitigation for the Micro-architectural Data
3437 full - Enable MDS mitigation on vulnerable CPUs
3438 full,nosmt - Enable MDS mitigation and disable
3440 off - Unconditionally disable MDS mitigation
3442 On TAA-affected machines, mds=off can be prevented by
3451 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3456 mem=nn[KMG] [KNL,BOOT,EARLY] Force usage of a specific amount
3466 [ARC,MICROBLAZE] - the limit applies only to low memory,
3469 [ARM64] - only limits memory covered by the linear
3477 Note that this only takes effects during boot time since
3478 in above case 3, memory may need be hot added after boot
3482 [ARM,MIPS,EARLY] - override the memory layout
3489 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3496 per-device physically contiguous DMA buffers.
3504 See Documentation/admin-guide/mm/memory-hotplug.rst.
3529 Example: Exclude memory from 0x18690000-0x1869ffff
3543 memmap=<size>%<offset>-<oldtype>+<newtype>
3545 from <oldtype> to <newtype>. If "-<oldtype>" is left
3560 repeatable BIOS-originated corruption always
3578 When enabled, runtime hotplugged memory will
3581 if hugetlb_free_vmemmap is enabled) from the
3591 Note that even when enabled, there are a few cases where
3604 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3610 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
3614 s2idle - Suspend-To-Idle
3615 shallow - Power-On Suspend or equivalent (if supported)
3616 deep - Suspend-To-RAM or equivalent (if supported)
3617 See Documentation/admin-guide/pm/sleep-states.rst.
3619 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
3635 0 - The attached screen is the 3.5" TFT
3636 1 - The attached screen is the 7" TFT
3637 2 - The VGA Shield is attached (1024x768)
3641 b - Enable backlight. The TFT backlight pin will be
3645 c - Enable the s3c camera interface.
3646 t - Reserved for enabling touchscreen support. The
3647 touchscreen support is not enabled in the mainstream
3650 https://repo.or.cz/w/linux-2.6/mini2440.git
3655 arch-independent options, each of which is an
3656 aggregation of existing arch-specific options.
3685 ssbd=force-off [ARM64]
3695 enabled, even if it's vulnerable. This is for
3698 have other ways of avoiding SMT-based attacks.
3733 full - Enable mitigation on vulnerable CPUs
3735 full,nosmt - Enable mitigation and disable SMT on
3738 off - Unconditionally disable mitigation
3751 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3781 module_blacklist= [KNL] Do not load a comma-separated list of
3806 movable_node [KNL,EARLY] Boot-time switch to make hotplugable memory
3813 Format: <name>,<region-number>,<size>,<offset>
3816 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3827 registers at boot time.
3855 something different and driver-specific.
3891 Only applies if the softerr mount option is enabled,
3895 [NFS] enable 64-bit inode numbers.
3896 If zero, the NFS client will fake up a 32-bit inode
3898 of returning the full 64-bit number.
3899 The default is to return 64-bit inode numbers.
3934 [NFS4] Specify an additional fixed unique ident-
3965 driver. A non-zero value sets the minimum interval
3970 server-to-server copies for which this server is
3982 server-to-server copy, knfsd temporarily mounts
3989 See Documentation/admin-guide/nfs/nfsroot.rst.
3991 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3992 See Documentation/admin-guide/nfs/nfsroot.rst.
3995 See Documentation/admin-guide/nfs/nfsroot.rst.
3999 NMI stack-backtrace request.
4008 0 - turn hardlockup detector in nmi_watchdog off
4009 1 - turn hardlockup detector in nmi_watchdog on
4010 rNNN - configure the watchdog with raw perf event 0xNNN
4023 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
4027 no4lvl [RISCV,EARLY] Disable 4-level and 5-level paging modes.
4028 Forces kernel to use 3-level paging instead.
4030 no5lvl [X86-64,RISCV,EARLY] Disable 5-level paging mode. Forces
4031 kernel to use 4-level paging instead.
4062 nodsp [SH] Disable hardware DSP at boot time.
4066 no_entry_flush [PPC,EARLY] Don't flush the L1-D cache when entering the kernel.
4068 noexec32 [X86-64]
4069 This affects only 32-bit executables.
4070 noexec32=on: enable non-executable mappings (default)
4072 noexec32=off: disable non-executable mappings
4079 nofpu [MIPS,SH] Disable hardware FPU at boot time.
4083 nofxsr [BUGS=X86-32] Disables x86 floating point extended
4085 legacy floating-point registers on task switch.
4098 compared. However, if this command-line option is
4125 nohz_full= [KNL,BOOT,SMP,ISOL]
4129 whenever possible. The boot CPU will be forced outside
4133 rcu_nocbs= boot parameter.
4141 nointremap [X86-64,Intel-IOMMU,EARLY] Do not enable interrupt
4143 [Deprecated - use intremap=off]
4149 noirqdebug [X86-32] Disables the code which attempts to detect and
4159 no-kvmapf [X86,KVM,EARLY] Disable paravirtualized asynchronous page
4162 no-kvmclock [X86,KVM,EARLY] Disable paravirtualized KVM clock driver
4164 nolapic [X86-32,APIC,EARLY] Do not enable or use the local APIC.
4166 nolapic_timer [X86-32,APIC,EARLY] Do not use the local APIC timer.
4168 nomce [X86-32] Disable Machine Check Exception
4170 nomfgpt [X86-32] Disable Multi-Function General Purpose
4176 not load if they could possibly displace the pre-
4179 perform display-mode changes or accelerated rendering.
4192 nopcid [X86-64,EARLY] Disable the PCID cpu feature.
4197 nopti [X86-64,EARLY]
4213 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
4219 no-scroll [VGA] Disables scrollback.
4220 This is required for the Braillex ib80-piezo Braille
4223 nosgx [X86-64,SGX,EARLY] Disables Intel SGX kernel support.
4243 nosoftlockup [KNL] Disable the soft-lockup detector.
4249 nospectre_bhb [ARM64,EARLY] Disable all mitigations for Spectre-BHB (branch
4262 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,LOONGARCH,EARLY]
4269 timer IRQ sources, i.e., the IO-APIC timer. This can
4274 [PPC,EARLY] Don't flush the L1-D cache after accessing user data.
4287 no-vmw-sched-clock
4292 soft-lockup and NMI watchdog (hard-lockup).
4296 nox2apic [X86-64,APIC,EARLY] Do not enable x2APIC mode.
4304 enabling legacy floating-point and sse state.
4311 xsaveopt supports it on xsaveopt enabled systems.
4319 memory on xsaves enabled systems.
4326 n. So during boot up some boot time memory for per-cpu
4327 variables need be pre-allocated for later physical cpu
4354 soft-reserved memory partitioning.
4360 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
4362 This can be set from sysctl after boot.
4363 See Documentation/admin-guide/sysctl/vm.rst for details.
4366 See Documentation/core-api/debugging-via-ohci1394.rst for more
4381 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4385 boundary - index of last SLC block on Flex-OneNAND.
4387 lock - Configure if Flex-OneNAND boundary should be locked.
4406 page_owner= [KNL,EARLY] Boot-time page_owner enabling option.
4412 page_poison= [KNL,EARLY] Boot-time parameter changing the state of
4440 See Documentation/admin-guide/tainted-kernels.rst for
4493 Set to non-zero to probe primary and secondary ISA
4499 Set to non-zero if a chip is present that snoops speed
4547 Set to non-zero to probe tertiary and further ISA
4563 Set to non-zero to probe QDI controllers. By default
4568 Set to non-zero to probe Winbond controllers. Use
4615 bios [X86-32] force use of PCI BIOS, don't access
4617 has a non-standard PCI host bridge.
4618 nobios [X86-32] disallow use of PCI BIOS, only direct
4624 data in IO port 0xCFC, both 32-bit).
4626 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4627 the function, IO port 0xCFA, also 8-bit, sets
4629 through ports 0xC000-0xCFFF).
4633 enabled, this kernel boot option can be used to
4636 root domains (aka PCI segments, in ACPI-speak).
4643 enabled, this kernel boot option can be used to
4644 disable the use of MSI interrupts system-wide.
4645 noioapicquirk [APIC] Disable all boot interrupt quirks.
4646 Safety option to keep boot IRQs enabled. This
4648 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
4649 primary IO-APIC for bridges that cannot disable
4650 boot IRQs. This fixes a source of spurious IRQs
4653 boot IRQ equivalent of an IRQ that connects to
4654 a chipset where boot IRQs cannot be disabled.
4656 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4680 F0000h-100000h range.
4685 assign-busses [X86] Always assign all PCI bus
4693 IRQ routing is enabled.
4698 is enabled by default. If you need to use this,
4706 <linux-pci@vger.kernel.org>.
4710 a bug to <linux-pci@vger.kernel.org>.
4722 bfsort Sort PCI devices into breadth-first order.
4725 nobfsort Don't sort PCI devices into breadth-first order.
4727 tuning and use the BIOS-configured MPS defaults.
4737 configuration allows peer-to-peer DMA between
4740 that hot-added devices will work.
4755 A PCI-PCI bridge can be specified if resource
4761 for 4096-byte alignment.
4763 end-to-end CRC checking). Only effective if
4794 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4820 capabilities will be enabled, disabled or
4825 bit-0 : ACS Source Validation
4826 bit-1 : ACS Translation Blocking
4827 bit-2 : ACS P2P Request Redirect
4828 bit-3 : ACS P2P Completion Redirect
4829 bit-4 : ACS Upstream Forwarding
4830 bit-5 : ACS P2P Egress Control
4831 bit-6 : ACS Direct Translated P2P
4834 '1' – force enabled
4841 Validation unchanged from whatever power-up
4851 is enabled, this kernel boot option can be used
4853 system-wide.
4867 dpc-native Use native PCIe service for DPC only. May
4884 Keep all power-domains already enabled by bootloader on,
4890 boot time.
4902 pirq= [SMP,APIC] Manual mp-table setup
4903 See Documentation/arch/x86/i386/IO-APIC.rst.
4907 See also Documentation/admin-guide/parport.rst.
4922 Enable suspend/resume debug messages during boot up.
4926 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4935 { on | off | curr | res | no-curr | no-res }
4980 none - Limited to cond_resched() calls
4981 voluntary - Limited to cond_resched() and might_sleep() calls
4982 full - Any section that isn't explicitly preempt disabled
4986 lazy - Scheduler controlled. Similar to full but instead
4992 print-fatal-signals=
4995 If enabled, warn about various signal handling
4998 coredump - etc.
5001 you might want to try "ulimit -i unlimited".
5013 or lockdep-detected issues (only if lock debug is on).
5018 default: 0 (auto_verbose is enabled)
5022 on - unlimited logging to /dev/kmsg from userspace
5023 off - logging to /dev/kmsg disabled
5024 ratelimit - ratelimit the logging
5035 - 'always': traditional behavior always allows mem overrides.
5036 - 'ptrace': only allow mem overrides for active ptracers.
5037 - 'never': never allow mem overrides.
5041 Limit processor to maximum C-state
5045 Ignore the _CST method to determine C-states,
5052 Param: "schedule" - profile schedule points.
5053 Param: "kvm" - profile VM exits.
5054 Param: <number> - step/bucket size as a power of 2 for
5061 that). If enabled, the default kernel base address
5081 0 = disabled, 1 = enabled (default).
5085 pti= [X86-64] Control Page Table Isolation of user and
5090 on - unconditionally enable
5091 off - unconditionally disable
5092 auto - kernel detects whether your CPU model is
5098 [KNL] Number of legacy pty's. Overwrites compiled-in
5110 See Documentation/admin-guide/md.rst.
5113 See Documentation/admin-guide/blockdev/ramdisk.rst.
5132 cross-syscall address exposures. This is only
5138 ras=option[,option,...] [KNL] RAS-specific options
5144 rcu_nocbs[=cpu-list]
5149 enable the no-callback CPU mode, which prevents
5154 "p" for RCU-preempt, "s" for RCU-sched, and "g"
5158 and real-time workloads. It can also improve
5162 list of CPUs is set to no-callback mode from boot.
5166 no-callback mode from boot but the mode may be
5177 This improves the real-time response for the
5188 Do only a one-line RCU CPU stall warning when
5189 there is an ongoing too-long CSD-lock wait.
5195 If triggered before the RCU grace-period machinery
5200 out at early boot. This is used for diagnostic
5205 RCU grace-period cleanup.
5209 RCU grace-period initialization.
5213 RCU grace-period pre-initialization, that is,
5214 the propagation of recent CPU-hotplug changes up
5218 Set delay from grace-period initialization to
5231 soliciting quiescent-state help from
5242 rcutree.kthread_prio= [KNL,BOOT]
5243 Set the SCHED_FIFO priority of the RCU per-CPU
5246 and for the RCU grace-period kthreads (rcu_bh,
5248 set, valid values are 1-99 and the default is 1
5249 (the least-favored priority). Otherwise, when
5250 RCU_BOOST is not set, valid values are 0-99 and
5251 the default is zero (non-realtime operation).
5256 On callback-offloaded (rcu_nocbs) CPUs,
5259 use of the ->nocb_bypass list. However, in the
5260 common non-flooded case, RCU queues directly to
5261 the main ->cblist in order to avoid the extra
5262 overhead of the ->nocb_bypass list and its lock.
5264 a single jiffy, RCU pre-queues the callbacks into
5265 the ->nocb_bypass queue. The definition of "too
5266 many" is supplied by this kernel boot parameter.
5269 On callback-offloaded (rcu_nocbs) CPUs, avoid
5282 batch limiting is re-enabled.
5286 RCU's force-quiescent-state scan will aggressively
5290 on rcutree.qhimark at boot time and to zero to
5294 Set the page-cache refill delay (in milliseconds)
5295 in response to low-memory conditions. The range
5299 Set the shift-right count to use to compute
5300 the callback-invocation batch limit bl from
5307 Please note that this callback-invocation batch
5308 limit applies only to non-offloaded callback
5317 cache-to-cache transfer latencies.
5323 and for NUMA systems with large remote-access
5339 the wakeup overhead on the global grace-period
5341 each group's NOCB grace-period kthread.
5344 Cause the grace-period kthread to get an extra
5346 it should at force-quiescent-state time.
5359 this specifies an rcu_read_unlock()-time delay
5363 of RCU-protected pointers after the relevant
5373 per-CPU rcuc kthreads. Defaults to a non-zero
5378 this kernel boot parameter, forcibly setting it
5396 or pass a boot parameter "rcutree.rcu_normal_wake_from_gp=1"
5402 grace-period primitives such as call_rcu().
5413 grace-period primitives.
5416 Set test-start holdoff period. The purpose of
5418 test until boot completes in order to avoid
5434 Test the double-argument variant of kfree_rcu().
5436 rcuscale.kfree_rcu_test_single, both the single-
5437 and double-argument variants are tested.
5440 Test the single-argument variant of kfree_rcu().
5442 rcuscale.kfree_rcu_test_double, both the single-
5443 and double-argument variants are tested.
5457 does not affect the data-collection interval,
5462 Set number of RCU readers. The value -1 selects
5464 "n" less than -1 selects N-n+1, where N is again
5465 the number of CPUs. For example, -2 selects N
5466 (the number of CPUs), -3 selects N+1, and so on.
5467 A value of "n" less than or equal to -N selects
5480 complete. This is useful for hands-off automated
5487 Write-side holdoff between grace periods,
5492 Additional write-side holdoff between grace
5510 for RCU grace-period forward-progress testing
5517 Specify the fraction of a CPU-stall-warning
5518 period to do tight-loop forward-progress testing.
5522 forward-progress tests.
5526 need_resched() during tight-loop forward-progress
5530 Use conditional/asynchronous update-side
5531 normal-grace-period primitives, if available.
5534 Use conditional/asynchronous update-side
5535 expedited-grace-period primitives, if available.
5538 Use conditional/asynchronous update-side
5539 normal-grace-period primitives that also take
5544 Use conditional/asynchronous update-side
5545 expedited-grace-period primitives that also take
5569 Use expedited update-side primitives, if available.
5572 Use normal (non-expedited) asynchronous
5573 update-side primitives, if available.
5576 Use polled update-side normal-grace-period
5580 Use polled update-side expedited-grace-period
5584 Use polled update-side normal-grace-period
5589 Use polled update-side expedited-grace-period
5613 Use normal (non-expedited) synchronous
5614 update-side primitives, if available. If all
5618 they are all non-zero.
5626 Leak an RCU-protected pointer out of the reader.
5641 Set number of RCU callback-offload togglers.
5646 callback-offload toggling attempts.
5649 Set number of RCU readers. The value -1 selects
5650 N-1, where N is the number of CPUs. A value
5651 "n" less than -1 selects N-n-2, where N is again
5652 the number of CPUs. For example, -2 selects N
5653 (the number of CPUs), -3 selects N+1, and so on.
5656 Enable debug-object double-call_rcu() testing.
5659 Set time (s) after boot for CPU-hotplug testing.
5662 Set time (jiffies) between CPU-hotplug operations,
5663 or zero to disable CPU-hotplug testing.
5667 by a high-priority FIFO real-time task. Set to
5676 second) between preemptions by a high-priority
5677 FIFO real-time task. This delay is mediated
5682 The number of times in a given read-then-exit
5683 episode that a set of read-then-exit kthreads
5688 read-then-exit testing episodes.
5693 are entered from low-order bit up, and are
5695 0x1 bit is normal readers, 0x2 NMI-safe readers,
5696 and 0x4 light-weight readers.
5699 Set task-shuffle interval (s). Shuffling tasks
5700 allows some CPUs to go into dyntick-idle mode
5704 Set time (s) after boot system shutdown. This
5705 is useful for hands-off automated testing.
5714 any other stall-related activity. Note that
5720 in scheduling-while-atomic splats.
5726 Time to wait (s) after boot before inducing stall.
5739 grace-period kthread to test RCU CPU stall
5765 Test RCU's dyntick-idle handling. See also the
5790 during early boot, that is, during the time
5820 Use expedited grace-period primitives, for
5824 real-time latency, and degrade energy efficiency.
5828 Use only normal grace-period primitives,
5831 real-time latency, CPU utilization, and
5833 increased grace-period latency. This parameter
5838 Once boot has completed (that is, after
5840 only normal grace-period primitives. No effect
5844 this kernel boot parameter, forcibly setting
5846 post-boot attempt at an expedited RCU grace
5847 period to instead use normal non-expedited
5848 grace-period processing.
5856 set to the default value of -1.
5859 Set the minimum number of callback-queuing-time
5860 lock-contention events per jiffy required to
5861 cause the RCU Tasks flavors to switch to per-CPU
5864 the default value of -1.
5869 of -1 allows this to be automatically (and
5877 number avoids disturbing real-time workloads,
5882 cancel laziness on that CPU. Use -1 to disable
5892 only printed prior to the stall-warning message
5932 Run the RCU early boot self tests
5940 force - Override the decision by the kernel to hide the
5979 There are some built-in platform specific "quirks"
5980 - you may see: "reboot: <name> series board detected.
5984 built-in quirk table, and use the generic default
6013 there may be boot problems on some systems.
6017 Set test-start holdoff period. The purpose of
6019 test until boot completes in order to avoid
6032 but the default has already reduced the per-pass
6037 Set number of readers. The default value of -1
6046 Set the read-side critical-section duration,
6050 Specify the read-protection implementation to test.
6076 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
6094 was from a previous boot, the new reservation will be at a
6098 boot, as there may be cases where the memory will not be
6106 reservetop= [X86-32,EARLY]
6123 See Documentation/power/swsusp-and-swap-files.rst
6132 retain_initrd [RAM] Keep initrd memory after extraction. After boot, it will
6139 AMD-based UNRET and IBPB mitigations alone do not stop
6141 sibling threads. For that reason, STIBP is used on pro-
6145 off - no mitigation
6146 auto - automatically select a migitation
6147 auto,nosmt - automatically select a mitigation,
6151 ibpb - On AMD, mitigate short speculation
6156 ibpb,nosmt - Like "ibpb" above but will disable SMT
6160 unret - Force enable untrained return thunks,
6161 only effective on AMD f15h-f17h based
6163 unret,nosmt - Like unret, but will disable SMT when STIBP
6189 When CONFIG_RISCV_ISA_FALLBACK is not enabled, permit
6195 ro [KNL] Mount root device read-only on boot
6198 on Mark read-only kernel memory as read-only (default).
6199 off Leave read-only kernel memory writable for debugging.
6200 full Mark read-only kernel memory and aliases as read-only
6207 debug-uart get routed to the D+ and D- pins of the usb
6213 block/early-lookup.c for details.
6238 rw [KNL] Mount root device read-write on boot
6292 to 10 seconds for built-in smp_call_function()
6299 that requesting even small non-zero numbers of
6306 The default of -1 specifies a number of kthreads
6311 test before initiating CPU-hotplug operations.
6315 CPU-hotplug operations. Specifying zero (which
6316 is the default) disables CPU-hotplug operations.
6322 Non-zero values are useful for automated tests.
6345 "wait" parameter. A value of -1 selects the
6346 default if all other weights are -1. However,
6348 value of -1 will instead select a weight of zero.
6353 non-zero "wait" parameter. See weight_single.
6366 non-zero "wait" parameter. See weight_single
6378 non-zero "wait" parameter. See weight_single
6389 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
6390 1 -- enable.
6392 enabled if running jitter sensitive (HPC/RT) workloads.
6395 enable at boot. This has been deprecated by the
6398 selinux= [SELINUX] Disable or enable SELinux at boot time.
6401 0 -- disable.
6402 1 -- enable.
6405 serialnumber [BUGS=X86-32]
6407 sev=option[,option...] [X86-64]
6413 Do not enable SEV-SNP (applies to host/hypervisor
6416 SEV-SNP guests.
6424 to set it to "all" by meaning -- no limit here.
6505 using the csdlock_debug- kernel parameter.
6510 system. By default, let CSD-lock acquisition
6512 for this value provides a 5-minute timeout.
6514 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
6515 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
6516 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
6517 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
6518 smsc-ircc2.ircc_irq= [HW] IRQ line
6519 smsc-ircc2.ircc_dma= [HW] DMA channel
6520 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
6530 Default: -1 (no limit)
6533 [KNL] Should the soft-lockup detector generate panics.
6536 A value of 1 instructs the soft-lockup detector
6537 to panic the machine when a soft-lockup occurs. It is
6540 respective build-time switch to that functionality.
6543 [KNL] Should the soft-lockup detector generate
6548 See Documentation/admin-guide/laptops/sonypi.rst
6555 on - (default) Enable the HW or SW mitigation as
6558 vmexit - On systems which don't have the HW mitigation
6561 protected from VM-originated BHI attacks, but
6563 off - Disable the mitigation.
6570 on - unconditionally enable, implies
6572 off - unconditionally disable, implies
6574 auto - kernel detects whether your CPU model is
6591 retpoline - replace indirect branches
6592 retpoline,generic - Retpolines
6593 retpoline,lfence - LFENCE; indirect branch
6594 retpoline,amd - alias for retpoline,lfence
6595 eibrs - Enhanced/Auto IBRS
6596 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
6597 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
6598 ibrs - use IBRS to protect kernel
6608 on - Unconditionally enable mitigations. Is
6611 off - Unconditionally disable mitigations. Is
6614 prctl - Indirect branch speculation is enabled,
6615 but mitigation can be enabled via prctl
6620 - Like "prctl" above, but only STIBP is
6626 - Same as "prctl" above, but all seccomp
6631 - Like "seccomp" above, but only STIBP is
6636 auto - Kernel selects the mitigation depending on
6647 off - Disable mitigation
6648 microcode - Enable microcode mitigation only
6649 safe-ret - Enable sw-only safe RET mitigation (default)
6650 ibpb - Enable mitigation by issuing IBPB on
6652 ibpb-vmexit - Issue IBPB only on VMEXIT
6653 (cloud-specific mitigation)
6678 on - Unconditionally disable Speculative Store Bypass
6679 off - Unconditionally enable Speculative Store Bypass
6680 auto - Kernel detects whether the CPU model contains an
6686 prctl - Control Speculative Store Bypass per thread
6687 via prctl. Speculative Store Bypass is enabled
6690 seccomp - Same as "prctl" above, but all seccomp threads
6698 on,auto - On Power8 and Power9 insert a store-forwarding
6702 off - No action.
6710 When enabled (and if hardware support is present), atomic
6716 off - not enabled
6718 warn - the kernel will emit rate-limited warnings
6724 enabled in hardware.
6726 fatal - the kernel will send SIGBUS to applications
6729 both features are enabled in hardware.
6731 ratelimit:N -
6751 Certain CPUs are vulnerable to an MDS-like
6771 This kernel-boot parameter defaults to 128,
6772 but takes effect only when the low-order four
6774 (decide at boot).
6784 3: Decide at boot time (default).
6789 instead of the compile-time CONFIG_NR_CPUS.
6793 grace-period sequence counter wrap for the
6794 srcu_data structure's ->srcu_gp_seq_needed field.
6809 Specifies the number of no-delay instances
6816 Specifies the per-grace-period phase, number of
6817 non-sleeping polls of readers. Beyond this limit,
6823 Specifies number of microseconds of non-sleeping
6824 delay between each non-sleeping poll of readers.
6827 Specifies the number of update-side contention
6832 set for contention-based conversions to occur.
6842 force-on: Unconditionally enable mitigation for
6844 force-off: Unconditionally disable mitigation for
6865 Enabled the stack tracer on boot up.
6867 stacktrace_filter=[function-list]
6869 will trace at boot up. function-list is a comma-separated
6877 Set the STI (builtin display/keyboard on the HP-PARISC
6879 as the initial boot-console.
6939 to global on non-NUMA machines)
6964 <int> -- Number of I/O TLB slabs
6965 <int> -- Second integer after comma. Number of swiotlb
6968 force -- force using of bounce buffers even if they
6970 noforce -- Never use bounce buffers (for debugging)
6985 Ignore sysrq setting - this boot parameter will
6993 cache size. See Documentation/networking/ip-sysctl.rst
7000 Specify "mem" (for Suspend-to-RAM) or "standby" (for
7005 wakeup-capable RTC alarm.
7011 -1: disable all active trip points in all thermal zones
7015 -1: disable all critical trip points in all thermal zones
7022 -1: disable all passive trip points
7028 <deci-seconds>: poll all this frequency
7032 Format: <size>[KMG],<size>[KMG]:<state>;<size>[KMG]-<size>[KMG]:<state>
7037 See Documentation/admin-guide/mm/transhuge.rst for more
7045 Format: <size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy>
7051 See Documentation/admin-guide/mm/transhuge.rst for more
7063 Prevent the CPU-hotplug component of torturing
7067 Dump the ftrace buffer at torture-test shutdown,
7071 with rotating-rust storage.
7076 disables verbose-printk() sleeping.
7079 Duration of each verbose-printk() sleep in jiffies.
7104 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
7108 tracing ring buffer. This is useful for early boot up
7131 printing of events during boot up, as user space may
7141 at boot up.
7142 local - Use the per CPU time stamp counter
7146 global - Event time stamps are synchronize across
7149 counter - Simple counting of events (1, 2, ..)
7153 uptime - Use jiffies as the time stamp.
7154 perf - Use the same clock that perf uses.
7155 mono - Use ktime_get_mono_fast_ns() for time stamps.
7156 mono_raw - Use ktime_get_raw_fast_ns() for time
7158 boot - Use ktime_get_boot_fast_ns() for time stamps.
7162 trace_event=[event-list]
7164 to facilitate early boot debugging. The event-list is a
7165 comma-separated list of trace events to enable. See
7176 trace_instance=[instance-info]
7177 [FTRACE] Create a ring buffer instance early in boot up.
7182 Events can be enabled at the time the instance is created
7201 traceoff - Have the tracing instance tracing disabled after it is created.
7202 traceprintk - Have trace_printk() write into this trace instance
7222 This will reserve 12 megabytes at boot up with a 4096 byte alignment
7231 If the ring buffer is used for persistent bootups and has events enabled,
7232 it is recommend to disable tracing so that events from a previous boot do not
7233 mix with events of the current boot (unless you are debugging a random crash
7234 at boot up).
7240 can force a memory reset on boot which will clear any trace that was stored.
7247 trace_options=[option-list]
7248 [FTRACE] Enable or disable tracer options at boot.
7249 The option-list is a comma delimited list of options
7250 that can be enabled or disabled just as if you were
7263 trace_trigger=[trigger-list]
7285 be enabled again by echoing '1' into the "tracing_on"
7300 See Documentation/admin-guide/mm/transhuge.rst
7307 See Documentation/admin-guide/mm/transhuge.rst
7314 See Documentation/admin-guide/mm/transhuge.rst
7322 - "tpm"
7323 - "tee"
7324 - "caam"
7325 - "dcp"
7335 - "kernel"
7336 - the same value as trusted.source: "tpm" or "tee"
7337 - "default"
7358 high-resolution timer mode on older hardware, and in
7394 on - Enable TSX on the system. Although there are
7397 several previous speculation-related CVEs, and
7399 with leaving it enabled.
7401 off - Disable TSX on the system. (Note that this
7409 auto - Disable TSX if X86_BUG_TAA is present,
7414 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7420 Similar to Micro-architectural Data Sampling (MDS)
7435 full - Enable TAA mitigation on vulnerable CPUs
7436 if TSX is enabled.
7438 full,nosmt - Enable TAA mitigation and disable SMT on
7441 vulnerable to cross-thread TAA attacks.
7442 off - Unconditionally disable TAA mitigation
7444 On MDS-affected machines, tsx_async_abort=off can be
7456 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7462 See also Documentation/input/devices/joystick-parport.rst
7464 udbg-immortal [PPC] When debugging early kernel crashes that
7466 console driver takes over, this boot options might
7470 Set number of hash buckets for UDP/UDP-Lite connections
7472 uhci-hcd.ignore_oc=
7474 Some badly-designed motherboards generate lots of
7483 unwind_debug [X86-64,EARLY]
7491 (default -1 = authorized (same as 1),
7497 for newly-detected USB devices (default 2). This
7522 if the first one fails (default 1 = enabled).
7525 [USB] Specifies timeout for the initial 64-byte
7532 [USB] A list of quirk entries to augment the built-in
7535 VendorID:ProductID:Flags. The IDs are 4-digit hex
7537 will change the built-in quirk; setting it if it is
7542 a 255-byte read);
7546 Set-Interface requests);
7565 (bInterval-1).
7603 usb-storage.delay_use=
7610 usb-storage.quirks=
7612 override the built-in unusual_devs list. List
7615 and Product ID values (4-digit hex numbers) and
7617 to a common usb-storage quirk flag as follows:
7659 medium is write-protected).
7668 1 - undefined instruction events
7669 2 - system calls
7670 4 - invalid data aborts
7671 8 - SIGSEGV faults
7672 16 - SIGBUS faults
7688 vdso32= [X86] Control the 32-bit vDSO
7689 vdso32=1: enable 32-bit VDSO
7690 vdso32=0 or vdso32=2: disable 32-bit VDSO
7700 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
7731 vga= [BOOT,X86-32] Select a particular video mode
7732 See Documentation/arch/x86/boot.rst and
7733 Documentation/admin-guide/svga.rst.
7735 This is actually a boot loader parameter; the value is
7739 May slow down system boot speed, especially when
7740 enabled on systems with a large amount of memory.
7741 All options are enabled by default, and this
7748 - Disable all of the above options
7750 vmalloc=nn[KMG] [KNL,BOOT,EARLY] Forces the vmalloc area to have an
7772 vsyscall= [X86-64,EARLY]
7775 code). Most statically-linked binaries and older
7799 see vga-softcursor.rst. Default: 2 = underline.
7804 This is a 16-member array composed of values
7805 ranging from 0-255.
7810 This is a 16-member array composed of values
7811 ranging from 0-255.
7816 This is a 16-member array composed of values
7817 ranging from 0-255.
7822 Set system-wide default UTF-8 mode for all tty's.
7823 Default is 1, i.e. UTF-8 mode is enabled for all
7828 Format=<-1|0|1>
7829 Set system-wide default for whether a cursor
7830 is shown on new VTs. Default is -1,
7835 vt.italic= [VT] Default color for italic text; 0-15.
7838 vt.underline= [VT] Default color for underlined text; 0-15.
7842 see Documentation/watchdog/watchdog-parameters.rst
7843 or other driver-specific files in the
7857 Format: <cpu-list>
7878 Per-cpu work items which run for longer than this
7881 them from noticeably delaying other per-cpu work
7899 Per-cpu workqueues are generally preferred because
7901 locality; unfortunately, per-cpu workqueues tend to
7904 Enabling this makes the per-cpu workqueues which
7918 Documentation/core-api/workqueue.rst.
7920 This can be changed after boot by writing to the
7931 forces round-robin CPU selection to flush out
7933 When enabled, memory and cache locality will be
7939 on - Enable writecombine, use WUC for ioremap_wc()
7940 off - Disable writecombine, use SUC for ioremap_wc()
7942 x2apic_phys [X86-64,APIC,EARLY] Use x2apic physical mode instead of
7946 xen_512gb_limit [KNL,X86-64,XEN]
7950 save/restore/migration must be enabled to handle larger
7956 ide-disks -- unplug primary master IDE devices
7957 aux-ide-disks -- unplug non-primary-master IDE devices
7958 nics -- unplug network devices
7959 all -- unplug all emulated devices (NICs and IDE disks)
7960 unnecessary -- unplugging emulated devices is
7963 never -- do not unplug even if version check succeeds
7972 bit, so it should only be enabled for obtaining extended
7977 Select whether to always use non-faulting (safe) MSR
7997 xen_timer_slop= [X86-64,XEN,EARLY]
8005 The time (in seconds) to wait before giving up to boot
8022 preferred over the 2-level event handling, as it is
8039 xive.store-eoi=off [PPC]
8045 xhci-hcd.quirks [USB,KNL]
8052 Controls if xmon debugger is enabled. Default is off.
8054 early Call xmon as early as possible on boot; xmon