Lines Matching +full:ps +full:- +full:source +full:- +full:off +full:- +full:time +full:- +full:ms
14 Format: { force | on | off | strict | noirq | rsdt |
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
26 source to check if firmware has set the FF flag. This
28 nospcr -- disable console in ACPI SPCR table as
30 For ARM64, ONLY "acpi=off", "acpi=on", "acpi=force" or
32 For RISCV64, ONLY "acpi=off", "acpi=on" or "acpi=force"
45 If set to vendor, prefer vendor-specific driver
71 _COMPONENT in an ACPI source file, e.g.,
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.
143 This option allows to turn off the feature.
149 Disable installation of static SSDTs at early boot time
153 This option turns off this feature.
159 Ignore the ACPI-based watchdog interface (WDAT) and let
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.
285 { off | try_unsupported }
286 off: disable AGP support
291 See Documentation/sound/alsa-configuration.rst
298 align_va_addr= [X86-64]
300 allocating a VMA at process creation time. This option
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
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
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]
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
487 Format: <int> (2 = AT (default), 3 = PS/2)
489 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
498 audit= [KNL] Enable the audit sub-system
499 Format: { "0" | "1" | "off" | "on" }
500 0 | off - kernel audit is disabled and can not be
502 unset - kernel audit is initialized but disabled and
504 1 | on - kernel audit is initialized and partially
517 0 - Disable the BAU.
518 1 - Enable the BAU.
519 unset - Disable the BAU.
558 See Documentation/block/cmdline-partition.rst
572 See Documentation/admin-guide/bootconfig.rst
577 bttv.pll= See Documentation/admin-guide/media/bttv.rst
580 bulk_remove=off [PPC] This parameter disables the use of the pSeries
582 at a time.
586 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
594 [NET] Specifies amount of time (in seconds) that
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
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]
736 Set the time in seconds that the clocksource
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
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.
877 "[time stamp] text\n" format (time stamp may not be
881 Switch to syslog format: "<%u>[time stamp] text\n"
884 syscall, or to executing "dmesg -S --raw" or to reading
901 1: enable debugging at boot time
907 cpuidle.off=1 [CPU_IDLE]
908 disable the cpuidle sub-system
913 cpufreq.off=1 [CPU_FREQ]
914 disable the cpufreq sub-system
922 [X86,EARLY] Delay for N microsec between assert and de-assert
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
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 }
1071 no-mount:
1075 off: Filesystem is not registered and clients
1076 get a -EPERM as result when trying to register files
1080 Default value is set in build-time with a kernel configuration.
1092 Documentation/admin-guide/mm/hugetlbpage.rst.
1100 of 0 will timeout at the end of initcalls. If the time
1106 delayacct [KNL] Enable per-task delay accounting
1133 Format: { on | off | def_only | inf_only | always }
1136 off: No s390 zlib hardware support
1187 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
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
1213 off: Turns OFF the mitigation.
1215 This parameter overrides the compile time default set
1222 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1246 Format: {"off" | "known"}
1247 Control how the dt_cpu_ftrs device-tree binding is
1250 off: Do not use it, fall back to legacy cpu table.
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
1426 be used at a time.
1454 Format: {"on" | "off" | "force"}
1457 off: disable H/W event reporting through EDAC.
1462 Format: {"off" | "on" | "skip[mbr]"}
1495 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
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).
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]
1589 Format: { on | off }
1591 off: disable FRED, the default setting.
1638 ftrace_filter=[function-list]
1640 tracer at boot up. function-list is a comma-separated
1642 time by the set_ftrace_filter file in the debugfs
1645 ftrace_notrace=[function-list]
1647 function-list. This list can be changed at run time
1651 ftrace_graph_filter=[function-list]
1654 function-list is a comma-separated list of functions
1655 that can be changed at run time by the
1658 ftrace_graph_notrace=[function-list]
1660 function-list. This list is a comma-separated list of
1661 functions that can be changed at run time by the
1667 can be changed at run time by the max_graph_depth file
1679 Format: { off | permissive | on | rpm }
1680 off -- Don't create device links from firmware info.
1681 permissive -- Create device links from firmware info
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
1716 Format: off | on
1737 off: Disable GDS mitigation.
1741 gcov_persist= [GCOV] When non-zero (default), profiling data for
1745 debugfs files are removed at module unload time.
1751 gpio-mockup.gpio_mockup_ranges
1754 gpio-mockup.gpio_mockup_named_lines
1786 against bounds-checking flaws in the kernel's
1789 off Disable hardened usercopy checks.
1792 [KNL] Should the hard-lockup detector generate
1798 for 64-bit NUMA, off otherwise.
1799 Format: 0 | 1 (for off | on)
1805 Disable Hardware Error Source Table (HEST) support;
1806 corresponding firmware-first mode error processing
1816 during restoration read-only).
1835 Valid parameters: "on", "off"
1853 hpet= [X86-32,HPET] option to control HPET usage
1870 number of pages to allocate per-node can be specified.
1871 See also Documentation/admin-guide/mm/hugetlbpage.rst.
1882 Documentation/admin-guide/mm/hugetlbpage.rst.
1893 boot-time allocation of gigantic hugepages is skipped.
1901 Format: { on | off (default) }
1904 off: disable HVO
1921 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
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
1969 i8042.direct [HW] Put keyboard port into non-translated mode
1983 suspend-to-ram transitions, only during s2r
2000 brightness value of 0 indicates backlight switched off,
2006 value switches the backlight off.
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/
2104 Format: { "off" | "enforce" | "fix" | "log" }
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
2236 0 -- basic integrity auditing messages. (Default)
2237 1 -- additional integrity auditing messages.
2242 off
2244 igfx_off [Default Off]
2250 strict [Default Off]
2252 sp_off [Default Off]
2262 tboot_noforce [Default Off]
2265 could harm performance of some high-throughput
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
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]
2322 off disable Interrupt Remapping
2323 nosid disable Source ID checking
2325 BIOS x2APIC opt-out request will be ignored
2336 off
2368 AMD Gart HW IOMMU-specific options:
2374 Overwrite iommu off workarounds for specific chipsets
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.
2483 Enables support for pseudo-NMIs in the kernel. This
2502 [Deprecated - use cpusets instead]
2503 Format: [flag-list,]<cpu-list>
2533 You can move a process onto or off an "isolated" CPU via
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
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).
2702 Configure the RouterBoard 532 series on-chip
2705 kmemleak= [KNL,EARLY] Boot-time kmemleak enable/disable
2706 Valid arguments: on, off
2709 the default is off.
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
2743 execution by eliminating the write-protection faults
2770 virtualization on-demand when creating and destroying
2778 is that doing so may interfere with using out-of-tree
2788 off : Never deploy workaround.
2804 [KVM] Controls the time period at which KVM zaps 4KiB pages
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
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
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
2890 kvm-intel.emulate_invalid_guest_state=
2892 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2898 kvm-intel.flexpriority=
2903 kvm-intel.nested=
2907 kvm-intel.unrestricted_guest=
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
2945 on - enable the interface for the mitigation
3001 off
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
3079 * [no]dbdelay: Enable or disable the extra 200ms delay
3083 * [no]ncq: Turn on or off NCQ.
3095 * [no]dma: Turn on or off DMA transfers.
3119 * external: Mark port as external (hotplug-capable).
3160 Set the time limit in jiffies for a lock
3173 Specify the number of self-propagating call_rcu()
3176 in progress at any given time. Defaults to 0,
3181 occasional long-duration lock hold time. Defaults
3192 Set the number of locking read-acquisition kthreads.
3197 Set the number of locking write-acquisition kthreads.
3200 Set time (s) after boot for CPU-hotplug testing.
3203 Set time (s) between CPU-hotplug operations, or
3204 zero to disable CPU-hotplug testing.
3207 Do periodic testing of real-time lock priority
3212 non-real-time spinlocks, due to their disabling
3213 of preemption. Note that non-realtime mutexes
3220 number of boosts per unit time remains roughly
3226 Set task-shuffle interval (jiffies). Shuffling
3227 tasks allows some CPUs to go into dyntick-idle
3231 Set time (s) after boot system shutdown. This
3232 is useful for hands-off automated testing.
3235 Time (s) between statistics printk()s.
3238 Time (s) to stutter testing, for example,
3251 Run the write-side locktorture kthreads at
3252 sched_set_fifo() real-time priority.
3270 7 (KERN_DEBUG) debug-level messages
3282 logo.nologo [FB] Disables display of the built-in Linux logo.
3300 an IEEE 1284-compliant printer is attached; if
3306 time-consuming boot-time autodetection (up to 250 ms per
3326 Example: machtype=lemote-yeeloong-2f-7inch
3338 (loop.max_loop) unconditionally pre-created at init time. The default
3341 devices can be requested on-demand with the
3342 /dev/loop-control interface.
3344 mce= [X86-{32,64}]
3348 off
3381 do not opt-in to Local MCE delivery. Use legacy method
3398 sets the time in us to wait for other CPUs on machine
3402 don't overwrite the bios-set CMCI threshold. This boot
3411 force-enable recoverable machine check code paths
3417 See Documentation/admin-guide/md.rst.
3424 Control mitigation for the Micro-architectural Data
3439 full - Enable MDS mitigation on vulnerable CPUs
3440 full,nosmt - Enable MDS mitigation and disable
3442 off - Unconditionally disable MDS mitigation
3444 On TAA-affected machines, mds=off can be prevented by
3447 this mitigation, you need to specify tsx_async_abort=off
3453 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3468 [ARC,MICROBLAZE] - the limit applies only to low memory,
3471 [ARM64] - only limits memory covered by the linear
3479 Note that this only takes effects during boot time since
3484 [ARM,MIPS,EARLY] - override the memory layout
3491 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3498 per-device physically contiguous DMA buffers.
3506 See Documentation/admin-guide/mm/memory-hotplug.rst.
3531 Example: Exclude memory from 0x18690000-0x1869ffff
3545 memmap=<size>%<offset>-<oldtype>+<newtype>
3547 from <oldtype> to <newtype>. If "-<oldtype>" is left
3562 repeatable BIOS-originated corruption always
3579 Format: {on | off (default)}
3606 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3607 Valid arguments: on, off
3608 Default: off
3610 mem_encrypt=off: Do not activate SME
3612 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
3616 s2idle - Suspend-To-Idle
3617 shallow - Power-On Suspend or equivalent (if supported)
3618 deep - Suspend-To-RAM or equivalent (if supported)
3619 See Documentation/admin-guide/pm/sleep-states.rst.
3621 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
3637 0 - The attached screen is the 3.5" TFT
3638 1 - The attached screen is the 7" TFT
3639 2 - The VGA Shield is attached (1024x768)
3643 b - Enable backlight. The TFT backlight pin will be
3647 c - Enable the s3c camera interface.
3648 t - Reserved for enabling touchscreen support. The
3652 https://repo.or.cz/w/linux-2.6/mini2440.git
3657 arch-independent options, each of which is an
3658 aggregation of existing arch-specific options.
3663 off
3668 gather_data_sampling=off [X86]
3669 kvm.nx_huge_pages=off [X86]
3670 l1tf=off [X86]
3671 mds=off [X86]
3672 mmio_stale_data=off [X86]
3680 reg_file_data_sampling=off [X86]
3681 retbleed=off [X86]
3682 spec_rstack_overflow=off [X86]
3683 spec_store_bypass_disable=off [X86,PPC]
3684 spectre_bhi=off [X86]
3685 spectre_v2_user=off [X86]
3686 srbds=off [X86,INTEL]
3687 ssbd=force-off [ARM64]
3688 tsx_async_abort=off [X86]
3700 have other ways of avoiding SMT-based attacks.
3735 full - Enable mitigation on vulnerable CPUs
3737 full,nosmt - Enable mitigation and disable SMT on
3740 off - Unconditionally disable mitigation
3743 mmio_stale_data=off can be prevented by an active
3747 mds=off and tsx_async_abort=off too.
3753 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3783 module_blacklist= [KNL] Do not load a comma-separated list of
3787 [MOUSE] Maximum time between finger touching and
3808 movable_node [KNL,EARLY] Boot-time switch to make hotplugable memory
3815 Format: <name>,<region-number>,<size>,<offset>
3818 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3829 registers at boot time.
3848 multitce=off [PPC] This parameter disables the use of the pSeries
3850 at a time.
3857 something different and driver-specific.
3858 This usage is only documented in each driver source
3862 [NET] Specifies amount of time (in seconds) that
3897 [NFS] enable 64-bit inode numbers.
3898 If zero, the NFS client will fake up a 32-bit inode
3900 of returning the full 64-bit number.
3901 The default is to return 64-bit inode numbers.
3933 To turn off this behaviour, set the value to '0'.
3936 [NFS4] Specify an additional fixed unique ident-
3939 UUID that is generated at system install time.
3967 driver. A non-zero value sets the minimum interval
3972 server-to-server copies for which this server is
3984 server-to-server copy, knfsd temporarily mounts
3985 the source server. It caches the mount in case
3991 See Documentation/admin-guide/nfs/nfsroot.rst.
3993 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3994 See Documentation/admin-guide/nfs/nfsroot.rst.
3997 See Documentation/admin-guide/nfs/nfsroot.rst.
4001 NMI stack-backtrace request.
4010 0 - turn hardlockup detector in nmi_watchdog off
4011 1 - turn hardlockup detector in nmi_watchdog on
4012 rNNN - configure the watchdog with raw perf event 0xNNN
4025 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
4029 no4lvl [RISCV,EARLY] Disable 4-level and 5-level paging modes.
4030 Forces kernel to use 3-level paging instead.
4032 no5lvl [X86-64,RISCV,EARLY] Disable 5-level paging mode. Forces
4033 kernel to use 4-level paging instead.
4059 turn on/off it dynamically.
4064 nodsp [SH] Disable hardware DSP at boot time.
4068 no_entry_flush [PPC,EARLY] Don't flush the L1-D cache when entering the kernel.
4070 noexec32 [X86-64]
4071 This affects only 32-bit executables.
4072 noexec32=on: enable non-executable mappings (default)
4074 noexec32=off: disable non-executable mappings
4081 nofpu [MIPS,SH] Disable hardware FPU at boot time.
4085 nofxsr [BUGS=X86-32] Disables x86 floating point extended
4087 legacy floating-point registers on task switch.
4100 compared. However, if this command-line option is
4124 Valid arguments: on, off
4143 nointremap [X86-64,Intel-IOMMU,EARLY] Do not enable interrupt
4145 [Deprecated - use intremap=off]
4151 noirqdebug [X86-32] Disables the code which attempts to detect and
4161 no-kvmapf [X86,KVM,EARLY] Disable paravirtualized asynchronous page
4164 no-kvmclock [X86,KVM,EARLY] Disable paravirtualized KVM clock driver
4166 nolapic [X86-32,APIC,EARLY] Do not enable or use the local APIC.
4168 nolapic_timer [X86-32,APIC,EARLY] Do not use the local APIC timer.
4170 nomce [X86-32] Disable Machine Check Exception
4172 nomfgpt [X86-32] Disable Multi-Function General Purpose
4178 not load if they could possibly displace the pre-
4181 perform display-mode changes or accelerated rendering.
4194 nopcid [X86-64,EARLY] Disable the PCID cpu feature.
4199 nopti [X86-64,EARLY]
4200 Equivalent to pti=off
4215 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
4221 no-scroll [VGA] Disables scrollback.
4222 This is required for the Braillex ib80-piezo Braille
4225 nosgx [X86-64,SGX,EARLY] Disables Intel SGX kernel support.
4245 nosoftlockup [KNL] Disable the soft-lockup detector.
4251 nospectre_bhb [ARM64,EARLY] Disable all mitigations for Spectre-BHB (branch
4264 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,LOONGARCH,EARLY]
4265 Disable paravirtualized steal time accounting. steal time
4271 timer IRQ sources, i.e., the IO-APIC timer. This can
4276 [PPC,EARLY] Don't flush the L1-D cache after accessing user data.
4289 no-vmw-sched-clock
4294 soft-lockup and NMI watchdog (hard-lockup).
4298 nox2apic [X86-64,APIC,EARLY] Do not enable x2APIC mode.
4306 enabling legacy floating-point and sse state.
4328 n. So during boot up some boot time memory for per-cpu
4329 variables need be pre-allocated for later physical cpu
4334 numa=off [KNL, ARM64, PPC, RISCV, SPARC, X86, EARLY]
4356 soft-reserved memory partitioning.
4365 See Documentation/admin-guide/sysctl/vm.rst for details.
4368 See Documentation/core-api/debugging-via-ohci1394.rst for more
4371 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
4372 Rather than timing out after 20 ms if an EC
4383 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4387 boundary - index of last SLC block on Flex-OneNAND.
4389 lock - Configure if Flex-OneNAND boundary should be locked.
4408 page_owner= [KNL,EARLY] Boot-time page_owner enabling option.
4414 page_poison= [KNL,EARLY] Boot-time parameter changing the state of
4417 off: turn off poisoning (default)
4442 See Documentation/admin-guide/tainted-kernels.rst for
4495 Set to non-zero to probe primary and secondary ISA
4501 Set to non-zero if a chip is present that snoops speed
4549 Set to non-zero to probe tertiary and further ISA
4565 Set to non-zero to probe QDI controllers. By default
4570 Set to non-zero to probe Winbond controllers. Use
4586 your oopses keep scrolling off the screen.
4616 off [X86] don't probe for the PCI bus
4617 bios [X86-32] force use of PCI BIOS, don't access
4619 has a non-standard PCI host bridge.
4620 nobios [X86-32] disallow use of PCI BIOS, only direct
4626 data in IO port 0xCFC, both 32-bit).
4628 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4629 the function, IO port 0xCFA, also 8-bit, sets
4631 through ports 0xC000-0xCFFF).
4638 root domains (aka PCI segments, in ACPI-speak).
4646 disable the use of MSI interrupts system-wide.
4651 primary IO-APIC for bridges that cannot disable
4652 boot IRQs. This fixes a source of spurious IRQs
4658 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4682 F0000h-100000h range.
4687 assign-busses [X86] Always assign all PCI bus
4708 <linux-[email protected]>.
4712 a bug to <linux-[email protected]>.
4724 bfsort Sort PCI devices into breadth-first order.
4727 nobfsort Don't sort PCI devices into breadth-first order.
4729 tuning and use the BIOS-configured MPS defaults.
4739 configuration allows peer-to-peer DMA between
4742 that hot-added devices will work.
4757 A PCI-PCI bridge can be specified if resource
4763 for 4096-byte alignment.
4765 end-to-end CRC checking). Only effective if
4770 off: Turn ECRC off
4792 off: Turn realloc off
4796 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4811 redirect capabilities forced off which will
4827 bit-0 : ACS Source Validation
4828 bit-1 : ACS Translation Blocking
4829 bit-2 : ACS P2P Request Redirect
4830 bit-3 : ACS P2P Completion Redirect
4831 bit-4 : ACS Upstream Forwarding
4832 bit-5 : ACS P2P Egress Control
4833 bit-6 : ACS Direct Translated P2P
4842 Translation Blocking, and leave Source
4843 Validation unchanged from whatever power-up
4855 system-wide.
4859 off Don't touch ASPM configuration at all. Leave any
4869 dpc-native Use native PCIe service for DPC only. May
4875 off Disable power management of all PCIe ports
4886 Keep all power-domains already enabled by bootloader on,
4892 boot time.
4904 pirq= [SMP,APIC] Manual mp-table setup
4905 See Documentation/arch/x86/i386/IO-APIC.rst.
4909 See also Documentation/admin-guide/parport.rst.
4928 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4934 { off }
4937 { on | off | curr | res | no-curr | no-res }
4964 powersave=off [PPC] This option disables power saving features.
4977 Format: {"off"}
4982 none - Limited to cond_resched() calls
4983 voluntary - Limited to cond_resched() and might_sleep() calls
4984 full - Any section that isn't explicitly preempt disabled
4988 lazy - Scheduler controlled. Similar to full but instead
4990 one HZ tick time to yield itself before the
4994 print-fatal-signals=
5000 coredump - etc.
5003 you might want to try "ulimit -i unlimited".
5005 default: off.
5015 or lockdep-detected issues (only if lock debug is on).
5022 printk.devkmsg={on,off,ratelimit}
5024 on - unlimited logging to /dev/kmsg from userspace
5025 off - logging to /dev/kmsg disabled
5026 ratelimit - ratelimit the logging
5029 printk.time= Show timing data prefixed to each printk message line
5037 - 'always': traditional behavior always allows mem overrides.
5038 - 'ptrace': only allow mem overrides for active ptracers.
5039 - 'never': never allow mem overrides.
5043 Limit processor to maximum C-state
5047 Ignore the _CST method to determine C-states,
5054 Param: "schedule" - profile schedule points.
5055 Param: "kvm" - profile VM exits.
5056 Param: <number> - step/bucket size as a power of 2 for
5057 statistical time based profiling.
5087 pti= [X86-64] Control Page Table Isolation of user and
5092 on - unconditionally enable
5093 off - unconditionally disable
5094 auto - kernel detects whether your CPU model is
5100 [KNL] Number of legacy pty's. Overwrites compiled-in
5112 See Documentation/admin-guide/md.rst.
5115 See Documentation/admin-guide/blockdev/ramdisk.rst.
5119 random.trust_cpu=off
5124 random.trust_bootloader=off
5134 cross-syscall address exposures. This is only
5140 ras=option[,option,...] [KNL] RAS-specific options
5146 rcu_nocbs[=cpu-list]
5151 enable the no-callback CPU mode, which prevents
5156 "p" for RCU-preempt, "s" for RCU-sched, and "g"
5160 and real-time workloads. It can also improve
5164 list of CPUs is set to no-callback mode from boot.
5168 no-callback mode from boot but the mode may be
5179 This improves the real-time response for the
5190 Do only a one-line RCU CPU stall warning when
5191 there is an ongoing too-long CSD-lock wait.
5197 If triggered before the RCU grace-period machinery
5207 RCU grace-period cleanup.
5211 RCU grace-period initialization.
5215 RCU grace-period pre-initialization, that is,
5216 the propagation of recent CPU-hotplug changes up
5220 Set delay from grace-period initialization to
5233 soliciting quiescent-state help from
5245 Set the SCHED_FIFO priority of the RCU per-CPU
5248 and for the RCU grace-period kthreads (rcu_bh,
5250 set, valid values are 1-99 and the default is 1
5251 (the least-favored priority). Otherwise, when
5252 RCU_BOOST is not set, valid values are 0-99 and
5253 the default is zero (non-realtime operation).
5258 On callback-offloaded (rcu_nocbs) CPUs,
5261 use of the ->nocb_bypass list. However, in the
5262 common non-flooded case, RCU queues directly to
5263 the main ->cblist in order to avoid the extra
5264 overhead of the ->nocb_bypass list and its lock.
5266 a single jiffy, RCU pre-queues the callbacks into
5267 the ->nocb_bypass queue. The definition of "too
5271 On callback-offloaded (rcu_nocbs) CPUs, avoid
5284 batch limiting is re-enabled.
5288 RCU's force-quiescent-state scan will aggressively
5292 on rcutree.qhimark at boot time and to zero to
5296 Set the page-cache refill delay (in milliseconds)
5297 in response to low-memory conditions. The range
5301 Set the shift-right count to use to compute
5302 the callback-invocation batch limit bl from
5309 Please note that this callback-invocation batch
5310 limit applies only to non-offloaded callback
5319 cache-to-cache transfer latencies.
5325 and for NUMA systems with large remote-access
5341 the wakeup overhead on the global grace-period
5343 each group's NOCB grace-period kthread.
5346 Cause the grace-period kthread to get an extra
5348 it should at force-quiescent-state time.
5353 Limit the time spend invoking a batch of RCU
5361 this specifies an rcu_read_unlock()-time delay
5365 of RCU-protected pointers after the relevant
5375 per-CPU rcuc kthreads. Defaults to a non-zero
5404 grace-period primitives such as call_rcu().
5415 grace-period primitives.
5418 Set test-start holdoff period. The purpose of
5436 Test the double-argument variant of kfree_rcu().
5438 rcuscale.kfree_rcu_test_single, both the single-
5439 and double-argument variants are tested.
5442 Test the single-argument variant of kfree_rcu().
5444 rcuscale.kfree_rcu_test_double, both the single-
5445 and double-argument variants are tested.
5458 Set the minimum test run time in seconds. This
5459 does not affect the data-collection interval,
5464 Set number of RCU readers. The value -1 selects
5466 "n" less than -1 selects N-n+1, where N is again
5467 the number of CPUs. For example, -2 selects N
5468 (the number of CPUs), -3 selects N+1, and so on.
5469 A value of "n" less than or equal to -N selects
5482 complete. This is useful for hands-off automated
5489 Write-side holdoff between grace periods,
5494 Additional write-side holdoff between grace
5503 Set holdoff time within force_quiescent_state bursts
5507 Set wait time between force_quiescent_state bursts
5512 for RCU grace-period forward-progress testing
5519 Specify the fraction of a CPU-stall-warning
5520 period to do tight-loop forward-progress testing.
5524 forward-progress tests.
5528 need_resched() during tight-loop forward-progress
5532 Use conditional/asynchronous update-side
5533 normal-grace-period primitives, if available.
5536 Use conditional/asynchronous update-side
5537 expedited-grace-period primitives, if available.
5540 Use conditional/asynchronous update-side
5541 normal-grace-period primitives that also take
5546 Use conditional/asynchronous update-side
5547 expedited-grace-period primitives that also take
5571 Use expedited update-side primitives, if available.
5574 Use normal (non-expedited) asynchronous
5575 update-side primitives, if available.
5578 Use polled update-side normal-grace-period
5582 Use polled update-side expedited-grace-period
5586 Use polled update-side normal-grace-period
5591 Use polled update-side expedited-grace-period
5615 Use normal (non-expedited) synchronous
5616 update-side primitives, if available. If all
5620 they are all non-zero.
5628 Leak an RCU-protected pointer out of the reader.
5643 Set number of RCU callback-offload togglers.
5648 callback-offload toggling attempts.
5651 Set number of RCU readers. The value -1 selects
5652 N-1, where N is the number of CPUs. A value
5653 "n" less than -1 selects N-n-2, where N is again
5654 the number of CPUs. For example, -2 selects N
5655 (the number of CPUs), -3 selects N+1, and so on.
5658 Enable debug-object double-call_rcu() testing.
5661 Set time (s) after boot for CPU-hotplug testing.
5664 Set time (jiffies) between CPU-hotplug operations,
5665 or zero to disable CPU-hotplug testing.
5669 by a high-priority FIFO real-time task. Set to
5672 are online at a given point in time. Races with
5678 second) between preemptions by a high-priority
5679 FIFO real-time task. This delay is mediated
5684 The number of times in a given read-then-exit
5685 episode that a set of read-then-exit kthreads
5690 read-then-exit testing episodes.
5695 are entered from low-order bit up, and are
5697 0x1 bit is normal readers, 0x2 NMI-safe readers,
5698 and 0x4 light-weight readers.
5701 Set task-shuffle interval (s). Shuffling tasks
5702 allows some CPUs to go into dyntick-idle mode
5706 Set time (s) after boot system shutdown. This
5707 is useful for hands-off automated testing.
5716 any other stall-related activity. Note that
5722 in scheduling-while-atomic splats.
5728 Time to wait (s) after boot before inducing stall.
5741 grace-period kthread to test RCU CPU stall
5747 Time (s) between statistics printk()s.
5750 Time (s) to stutter testing, for example, specifying
5767 Test RCU's dyntick-idle handling. See also the
5792 during early boot, that is, during the time
5822 Use expedited grace-period primitives, for
5826 real-time latency, and degrade energy efficiency.
5830 Use only normal grace-period primitives,
5833 real-time latency, CPU utilization, and
5835 increased grace-period latency. This parameter
5842 only normal grace-period primitives. No effect
5848 post-boot attempt at an expedited RCU grace
5849 period to instead use normal non-expedited
5850 grace-period processing.
5858 set to the default value of -1.
5861 Set the minimum number of callback-queuing-time
5862 lock-contention events per jiffy required to
5863 cause the RCU Tasks flavors to switch to per-CPU
5866 the default value of -1.
5871 of -1 allows this to be automatically (and
5876 Set time in jiffies during which RCU tasks will
5879 number avoids disturbing real-time workloads,
5884 cancel laziness on that CPU. Use -1 to disable
5894 only printed prior to the stall-warning message
5901 Multiplier for time interval between successive
5942 force - Override the decision by the kernel to hide the
5949 Turn on/off individual RDT features. List is:
5952 E.g. to turn on cmt and turn off mba use:
5981 There are some built-in platform specific "quirks"
5982 - you may see: "reboot: <name> series board detected.
5986 built-in quirk table, and use the generic default
6019 Set test-start holdoff period. The purpose of
6034 but the default has already reduced the per-pass
6039 Set number of readers. The default value of -1
6048 Set the read-side critical-section duration,
6052 Specify the read-protection implementation to test.
6078 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
6108 reservetop= [X86-32,EARLY]
6125 See Documentation/power/swsusp-and-swap-files.rst
6141 AMD-based UNRET and IBPB mitigations alone do not stop
6143 sibling threads. For that reason, STIBP is used on pro-
6147 off - no mitigation
6148 auto - automatically select a migitation
6149 auto,nosmt - automatically select a mitigation,
6153 ibpb - On AMD, mitigate short speculation
6158 ibpb,nosmt - Like "ibpb" above but will disable SMT
6162 unret - Force enable untrained return thunks,
6163 only effective on AMD f15h-f17h based
6165 unret,nosmt - Like unret, but will disable SMT when STIBP
6170 time according to the CPU.
6197 ro [KNL] Mount root device read-only on boot
6200 on Mark read-only kernel memory as read-only (default).
6201 off Leave read-only kernel memory writable for debugging.
6202 full Mark read-only kernel memory and aliases as read-only
6209 debug-uart get routed to the D+ and D- pins of the usb
6215 block/early-lookup.c for details.
6231 rootwait= [KNL] Maximum time (in seconds) to wait for root device
6240 rw [KNL] Mount root device read-write on boot
6279 signals(usually 32 ms but configurable). Setting
6283 i.e. with the default pelt decay period of 32 ms
6285 1 64 ms
6286 2 128 ms
6292 Number of seconds to hold off before starting
6294 to 10 seconds for built-in smp_call_function()
6301 that requesting even small non-zero numbers of
6308 The default of -1 specifies a number of kthreads
6313 test before initiating CPU-hotplug operations.
6317 CPU-hotplug operations. Specifying zero (which
6318 is the default) disables CPU-hotplug operations.
6324 Non-zero values are useful for automated tests.
6347 "wait" parameter. A value of -1 selects the
6348 default if all other weights are -1. However,
6350 value of -1 will instead select a weight of zero.
6355 non-zero "wait" parameter. See weight_single.
6368 non-zero "wait" parameter. See weight_single
6380 non-zero "wait" parameter. See weight_single
6391 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
6392 1 -- enable.
6400 selinux= [SELINUX] Disable or enable SELinux at boot time.
6403 0 -- disable.
6404 1 -- enable.
6407 serialnumber [BUGS=X86-32]
6409 sev=option[,option...] [X86-64]
6415 Do not enable SEV-SNP (applies to host/hypervisor
6418 SEV-SNP guests.
6426 to set it to "all" by meaning -- no limit here.
6499 Specify the period of time in milliseconds
6504 of time. Defaults to 5,000 milliseconds, and
6507 using the csdlock_debug- kernel parameter.
6512 system. By default, let CSD-lock acquisition
6514 for this value provides a 5-minute timeout.
6516 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
6517 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
6518 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
6519 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
6520 smsc-ircc2.ircc_irq= [HW] IRQ line
6521 smsc-ircc2.ircc_dma= [HW] DMA channel
6522 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
6532 Default: -1 (no limit)
6535 [KNL] Should the soft-lockup detector generate panics.
6538 A value of 1 instructs the soft-lockup detector
6539 to panic the machine when a soft-lockup occurs. It is
6542 respective build-time switch to that functionality.
6545 [KNL] Should the soft-lockup detector generate
6550 See Documentation/admin-guide/laptops/sonypi.rst
6557 on - (default) Enable the HW or SW mitigation as
6560 vmexit - On systems which don't have the HW mitigation
6563 protected from VM-originated BHI attacks, but
6565 off - Disable the mitigation.
6572 on - unconditionally enable, implies
6574 off - unconditionally disable, implies
6575 spectre_v2_user=off
6576 auto - kernel detects whether your CPU model is
6580 mitigation method at run time according to the
6588 Selecting 'off' will disable both the kernel and
6593 retpoline - replace indirect branches
6594 retpoline,generic - Retpolines
6595 retpoline,lfence - LFENCE; indirect branch
6596 retpoline,amd - alias for retpoline,lfence
6597 eibrs - Enhanced/Auto IBRS
6598 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
6599 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
6600 ibrs - use IBRS to protect kernel
6610 on - Unconditionally enable mitigations. Is
6613 off - Unconditionally disable mitigations. Is
6614 enforced by spectre_v2=off
6616 prctl - Indirect branch speculation is enabled,
6622 - Like "prctl" above, but only STIBP is
6628 - Same as "prctl" above, but all seccomp
6633 - Like "seccomp" above, but only STIBP is
6638 auto - Kernel selects the mitigation depending on
6649 off - Disable mitigation
6650 microcode - Enable microcode mitigation only
6651 safe-ret - Enable sw-only safe RET mitigation (default)
6652 ibpb - Enable mitigation by issuing IBPB on
6654 ibpb-vmexit - Issue IBPB only on VMEXIT
6655 (cloud-specific mitigation)
6680 on - Unconditionally disable Speculative Store Bypass
6681 off - Unconditionally enable Speculative Store Bypass
6682 auto - Kernel detects whether the CPU model contains an
6685 CPU is not vulnerable, "off" is selected. If the
6688 prctl - Control Speculative Store Bypass per thread
6692 seccomp - Same as "prctl" above, but all seccomp threads
6700 on,auto - On Power8 and Power9 insert a store-forwarding
6704 off - No action.
6718 off - not enabled
6720 warn - the kernel will emit rate-limited warnings
6728 fatal - the kernel will send SIGBUS to applications
6733 ratelimit:N -
6753 Certain CPUs are vulnerable to an MDS-like
6766 off: Disable mitigation and remove
6773 This kernel-boot parameter defaults to 128,
6774 but takes effect only when the low-order four
6784 1: At init_srcu_struct() time.
6786 3: Decide at boot time (default).
6791 instead of the compile-time CONFIG_NR_CPUS.
6795 grace-period sequence counter wrap for the
6796 srcu_data structure's ->srcu_gp_seq_needed field.
6811 Specifies the number of no-delay instances
6818 Specifies the per-grace-period phase, number of
6819 non-sleeping polls of readers. Beyond this limit,
6825 Specifies number of microseconds of non-sleeping
6826 delay between each non-sleeping poll of readers.
6829 Specifies the number of update-side contention
6834 set for contention-based conversions to occur.
6844 force-on: Unconditionally enable mitigation for
6846 force-off: Unconditionally disable mitigation for
6869 stacktrace_filter=[function-list]
6871 will trace at boot up. function-list is a comma-separated
6873 time by the stack_trace_filter file in the debugfs
6879 Set the STI (builtin display/keyboard on the HP-PARISC
6881 as the initial boot-console.
6941 to global on non-NUMA machines)
6960 Format: { on | off | y | n | 1 | 0 }
6966 <int> -- Number of I/O TLB slabs
6967 <int> -- Second integer after comma. Number of swiotlb
6970 force -- force using of bounce buffers even if they
6972 noforce -- Never use bounce buffers (for debugging)
6987 Ignore sysrq setting - this boot parameter will
6995 cache size. See Documentation/networking/ip-sysctl.rst
7002 Specify "mem" (for Suspend-to-RAM) or "standby" (for
7007 wakeup-capable RTC alarm.
7013 -1: disable all active trip points in all thermal zones
7017 -1: disable all critical trip points in all thermal zones
7020 thermal.off= [HW,ACPI]
7024 -1: disable all passive trip points
7030 <deci-seconds>: poll all this frequency
7034 Format: <size>[KMG],<size>[KMG]:<state>;<size>[KMG]-<size>[KMG]:<state>
7039 See Documentation/admin-guide/mm/transhuge.rst for more
7047 Format: <size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy>
7053 See Documentation/admin-guide/mm/transhuge.rst for more
7057 Format: {off | on}
7065 Prevent the CPU-hotplug component of torturing
7069 Dump the ftrace buffer at torture-test shutdown,
7073 with rotating-rust storage.
7078 disables verbose-printk() sleeping.
7081 Duration of each verbose-printk() sleep in jiffies.
7094 Specify that at suspend time, the tpm driver
7106 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
7115 To turn off having tracepoints sent to printk,
7137 to console at the late_initcall_sync() time frame.
7144 local - Use the per CPU time stamp counter
7148 global - Event time stamps are synchronize across
7151 counter - Simple counting of events (1, 2, ..)
7155 uptime - Use jiffies as the time stamp.
7156 perf - Use the same clock that perf uses.
7157 mono - Use ktime_get_mono_fast_ns() for time stamps.
7158 mono_raw - Use ktime_get_raw_fast_ns() for time
7160 boot - Use ktime_get_boot_fast_ns() for time stamps.
7164 trace_event=[event-list]
7166 to facilitate early boot debugging. The event-list is a
7167 comma-separated list of trace events to enable. See
7178 trace_instance=[instance-info]
7184 Events can be enabled at the time the instance is created
7195 the same thing would happen if it was left off). The irq_handler_entry
7203 traceoff - Have the tracing instance tracing disabled after it is created.
7204 traceprintk - Have trace_printk() write into this trace instance
7226 memory may not be the same location each time, which will not preserve
7249 trace_options=[option-list]
7251 The option-list is a comma delimited list of options
7265 trace_trigger=[trigger-list]
7286 warning is hit. This turns off "tracing_on". Tracing can
7294 This option can also be set at run time via the sysctl
7302 See Documentation/admin-guide/mm/transhuge.rst
7309 See Documentation/admin-guide/mm/transhuge.rst
7316 See Documentation/admin-guide/mm/transhuge.rst
7319 trusted.source= [KEYS]
7321 This parameter identifies the trust source as a backend
7324 - "tpm"
7325 - "tee"
7326 - "caam"
7327 - "dcp"
7329 the trust source list starting with TPM and assigns the
7330 first trust source as a backend which is initialized
7337 - "kernel"
7338 - the same value as trusted.source: "tpm" or "tee"
7339 - "default"
7341 the RNG's choice is left to each individual trust source.
7345 trusted.source=dcp and will select the DCP OTP key
7350 trusted.source=dcp and will disable the check if the
7360 high-resolution timer mode on older hardware, and in
7363 Used to run time disable IRQ_TIME_ACCOUNTING on any
7396 on - Enable TSX on the system. Although there are
7399 several previous speculation-related CVEs, and
7403 off - Disable TSX on the system. (Note that this
7411 auto - Disable TSX if X86_BUG_TAA is present,
7414 Not specifying this option is equivalent to tsx=off.
7416 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7422 Similar to Micro-architectural Data Sampling (MDS)
7437 full - Enable TAA mitigation on vulnerable CPUs
7440 full,nosmt - Enable TAA mitigation and disable SMT on
7443 vulnerable to cross-thread TAA attacks.
7444 off - Unconditionally disable TAA mitigation
7446 On MDS-affected machines, tsx_async_abort=off can be
7449 this mitigation, you need to specify mds=off too.
7458 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7464 See also Documentation/input/devices/joystick-parport.rst
7466 udbg-immortal [PPC] When debugging early kernel crashes that
7472 Set number of hash buckets for UDP/UDP-Lite connections
7474 uhci-hcd.ignore_oc=
7476 Some badly-designed motherboards generate lots of
7485 unwind_debug [X86-64,EARLY]
7493 (default -1 = authorized (same as 1),
7498 [USB] The autosuspend time delay (in seconds) used
7499 for newly-detected USB devices (default 2). This
7500 is the time required before an idle device will be
7505 [USB] Set to log all usbfs traffic (default 0 = off).
7512 [USB] Set to cycle leds on hubs (default 0 = off).
7516 scheme (default 0 = off).
7527 [USB] Specifies timeout for the initial 64-byte
7534 [USB] A list of quirk entries to augment the built-in
7537 VendorID:ProductID:Flags. The IDs are 4-digit hex
7539 will change the built-in quirk; setting it if it is
7544 a 255-byte read);
7548 Set-Interface requests);
7567 (bInterval-1).
7593 request from 5000 ms to 500 ms);
7605 usb-storage.delay_use=
7609 suffix with "ms".
7610 Example: delay_use=2567ms
7612 usb-storage.quirks=
7614 override the built-in unusual_devs list. List
7617 and Product ID values (4-digit hex numbers) and
7619 to a common usb-storage quirk flag as follows:
7633 240 sectors at a time, uas only);
7645 than 64 sectors = 32 KB at a time,
7661 medium is write-protected).
7670 1 - undefined instruction events
7671 2 - system calls
7672 4 - invalid data aborts
7673 8 - SIGSEGV faults
7674 16 - SIGBUS faults
7690 vdso32= [X86] Control the 32-bit vDSO
7691 vdso32=1: enable 32-bit VDSO
7692 vdso32=0 or vdso32=2: disable 32-bit VDSO
7702 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
7733 vga= [BOOT,X86-32] Select a particular video mode
7735 Documentation/admin-guide/svga.rst.
7749 P Enable page structure init time poisoning
7750 - Disable all of the above options
7771 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
7774 vsyscall= [X86-64,EARLY]
7777 code). Most statically-linked binaries and older
7801 see vga-softcursor.rst. Default: 2 = underline.
7806 This is a 16-member array composed of values
7807 ranging from 0-255.
7812 This is a 16-member array composed of values
7813 ranging from 0-255.
7818 This is a 16-member array composed of values
7819 ranging from 0-255.
7824 Set system-wide default UTF-8 mode for all tty's.
7825 Default is 1, i.e. UTF-8 mode is enabled for all
7830 Format=<-1|0|1>
7831 Set system-wide default for whether a cursor
7832 is shown on new VTs. Default is -1,
7837 vt.italic= [VT] Default color for italic text; 0-15.
7840 vt.underline= [VT] Default color for underlined text; 0-15.
7844 see Documentation/watchdog/watchdog-parameters.rst
7845 or other driver-specific files in the
7859 Format: <cpu-list>
7880 Per-cpu work items which run for longer than this
7883 them from noticeably delaying other per-cpu work
7884 items. Default is 10000 (10ms).
7901 Per-cpu workqueues are generally preferred because
7903 locality; unfortunately, per-cpu workqueues tend to
7906 Enabling this makes the per-cpu workqueues which
7920 Documentation/core-api/workqueue.rst.
7933 forces round-robin CPU selection to flush out
7941 on - Enable writecombine, use WUC for ioremap_wc()
7942 off - Disable writecombine, use SUC for ioremap_wc()
7944 x2apic_phys [X86-64,APIC,EARLY] Use x2apic physical mode instead of
7948 xen_512gb_limit [KNL,X86-64,XEN]
7958 ide-disks -- unplug primary master IDE devices
7959 aux-ide-disks -- unplug non-primary-master IDE devices
7960 nics -- unplug network devices
7961 all -- unplug all emulated devices (NICs and IDE disks)
7962 unnecessary -- unplugging emulated devices is
7965 never -- do not unplug even if version check succeeds
7979 Select whether to always use non-faulting (safe) MSR
7999 xen_timer_slop= [X86-64,XEN,EARLY]
8007 The time (in seconds) to wait before giving up to boot
8018 After which time (jiffies) the event handling loop
8024 preferred over the 2-level event handling, as it is
8037 off Fallback to firmware control of XIVE interrupt
8041 xive.store-eoi=off [PPC]
8047 xhci-hcd.quirks [USB,KNL]
8053 Format: { early | on | rw | ro | off }
8054 Controls if xmon debugger is enabled. Default is off.
8069 off xmon is disabled.