Lines Matching +full:timer +full:- +full:cannot +full:- +full:wake +full:- +full:cpu
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
77 Documentation/firmware-guide/acpi/debug.rst for more information about
131 GPE floodings that cannot be automatically disabled by
135 Format: <byte> or <bitmap-list>
138 Disable auto-serialization of AML methods
141 auto-serialization 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
190 it cannot affect the default state of the feature group
201 'acpi_osi=' cannot be used in combination with other
244 For broken nForce2 BIOS resulting in XT-PIC timer.
253 as soon as the kernel's real-mode entry point is called.
278 Use timer override. For some broken Nvidia NF5 boards
279 that require a timer override, but don't have HPET
291 See Documentation/sound/alsa-configuration.rst
298 align_va_addr= [X86-64]
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
323 EL0 is indicated by /sys/devices/system/cpu/aarch32_el0
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.
422 bsp: External NMI is delivered only to CPU 0
424 backup of CPU 0
429 apicpmtimer Do APIC timer calibration using the pmtimer. Implies
430 apicmaintimer. Useful when your PIT timer is totally
442 0 -- disable.
443 1 -- enable.
446 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
494 audit= [KNL] Enable the audit sub-system
496 0 | off - kernel audit is disabled and can not be
498 unset - kernel audit is initialized but disabled and
500 1 | on - kernel audit is initialized and partially
513 0 - Disable the BAU.
514 1 - Enable the BAU.
515 unset - Disable the BAU.
554 See Documentation/block/cmdline-partition.rst
568 See Documentation/admin-guide/bootconfig.rst
573 bttv.pll= See Documentation/admin-guide/media/bttv.rst
582 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
583 Sometimes CPU hardware bugs make them report the cache
601 inclusive. See arch/mips/include/asm/pgtable-bits.h
611 - foo isn't auto-mounted if you mount all cgroups in
613 - foo isn't visible as an individually mountable
615 - if foo is an optional feature then the feature is
621 Specifying "pressure" disables per-cgroup pressure
639 nosocket -- Disable socket memory accounting.
640 nokmem -- Disable kernel memory accounting.
641 nobpf -- Disable BPF memory accounting.
646 0 -- check protection applied by kernel (includes
648 1 -- check protection requested by application.
660 numbers X. Note the Linux-specific bits are not necessarily
661 stable over kernel options, but the vendor-specific
681 force such clocks to be always-on nor does it reserve
685 information, see Documentation/driver-api/clk.rst.
687 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
704 [X86-32] pit,hpet,tsc;
711 [X86-64] hpet,tsc
717 architected timer so that code using WFE-based polling
729 no replacement if the same CPU is chosen twice.
731 clocksource-wdtest.holdoff= [KNL]
737 cma=nn[MG]@[start[MG][-end[MG]]]
748 Sets the size of kernel per-numa memory area for
750 per-numa CMA altogether. And If this option is not
752 With per-numa CMA enabled, DMA users on node nid will
779 com20020= [HW,NET] ARCnet - COM20020 chipset
783 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
787 ARCnet - COM90xx chipset (memory-mapped buffers)
816 See Documentation/admin-guide/serial-console.rst for more
831 $ ls -d /sys/bus/serial-base/devices/*:*.*/tty/*
832 /sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0
845 Start an early, polled-mode console on the 8250/16550
848 MMIO inter-register address stride is either 8-bit
849 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
853 the h/w is not re-initialized.
880 syscall, or to executing "dmesg -S --raw" or to reading
884 seconds. A value of 0 disables the blank timer.
895 Enable/disable the CPU sampling based debugging.
904 disable the cpuidle sub-system
910 disable the cpufreq sub-system
918 [X86,EARLY] Delay for N microsec between assert and de-assert
920 on every CPU online, such as boot, and resume from suspend.
939 like Hyper-V, PowerPC (fadump) and AMD SEV-SNP.
947 [KNL, X86-64, ARM64, RISCV, LoongArch] Select a region
950 See Documentation/admin-guide/kdump/kdump.rst for further details.
955 start-[end] where start and end are both
957 Documentation/admin-guide/kdump/kdump.rst for an example.
960 [KNL, X86-64, ARM64, RISCV, LoongArch] range could be
968 [KNL, X86-64, ARM64, RISCV, LoongArch] range under 4G.
974 for 32-bit devices won't run out. Kernel would try to allocate
977 --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
978 --> arm64: 128MiB
979 --> riscv: 128MiB
980 --> loongarch: 128MiB
988 [KNL] Disable crypto self-tests
996 csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
999 in case a hanging CPU is detected, and that
1000 CPU is pinged again in order to try to resolve
1011 See also Documentation/input/devices/joystick-parport.rst
1024 [KNL] verbose locking self-tests
1027 self-tests.
1029 (no extra messages), setting it to -1 (all bits set)
1030 will print _a_lot_ more information - normally only
1045 kernel or driver code when a CPU writes to (or reads
1050 CPU MMU is bypassed) which are not detectable by
1065 Format: { on, no-mount, off }
1067 no-mount:
1072 get a -EPERM as result when trying to register files
1076 Default value is set in build-time with a kernel configuration.
1088 Documentation/admin-guide/mm/hugetlbpage.rst.
1102 delayacct [KNL] Enable per-task delay accounting
1178 Disable PIN 1 of APIC timer
1188 entries for DMA-API debugging code. One entry is
1189 required per DMA-API allocation. Use this if the
1190 DMA-API debugging code disables itself because the
1194 With this option the DMA-API debugging driver
1202 Sampling (RFDS) vulnerability. RFDS is a CPU
1212 by CONFIG_MITIGATION_RFDS. Mitigation cannot be
1218 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1243 Control how the dt_cpu_ftrs device-tree binding is
1244 used for CPU feature discovery and setup (if it
1246 off: Do not use it, fall back to legacy cpu table.
1253 what data is available or for reverse-engineering.
1258 Documentation/admin-guide/dynamic-debug-howto.rst
1269 determined by stdout-path property in device tree's
1274 Start an early, polled-mode console on a Cadence
1285 Start an early, polled-mode console on the 8250/16550
1287 MMIO inter-register address stride is either 8-bit
1288 (mmio) or 32-bit (mmio32 or mmio32be).
1298 Start an early, polled-mode console on a pl011 serial
1302 the driver will use only 32-bit accessors to read/write
1311 Start an early, polled-mode console on a meson serial
1317 Start an early, polled-mode console on an msm serial
1323 Start an early, polled-mode console on an msm serial
1329 Start an early, polled-mode console on a serial port
1335 Start an early, polled-mode console on a serial port
1341 Use RISC-V SBI (Supervisor Binary Interface) for early
1359 Start an early, polled-mode console on a lantiq serial
1373 Start an early, polled-mode, output-only console on the
1378 Start an early, polled-mode console on the
1384 Start an early, polled-mode console on a Qualcomm
1392 coherent non-x86 systems that use system memory for
1495 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1512 elanfreq= [X86-32]
1514 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
1520 See Documentation/admin-guide/kdump/kdump.rst for details.
1528 Enable PIN 1 of APIC timer
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]
1620 will dump only the buffer of the CPU that triggered
1624 instance supports only dump on CPU that triggered the
1630 on CPU that triggered the oops.
1636 of "bar" instance on CPU that triggered the oops.
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]
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
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
1741 gcov_persist= [GCOV] When non-zero (default), profiling data for
1751 gpio-mockup.gpio_mockup_ranges
1754 gpio-mockup.gpio_mockup_named_lines
1786 against bounds-checking flaws in the kernel's
1794 [KNL] Should the hard-lockup detector generate
1800 for 64-bit NUMA, off otherwise.
1808 corresponding firmware-first mode error processing
1818 during restoration read-only).
1836 highres= [KNL] Enable/disable high resolution timer mode.
1855 hpet= [X86-32,HPET] option to control HPET usage
1872 number of pages to allocate per-node can be specified.
1873 See also Documentation/admin-guide/mm/hugetlbpage.rst.
1884 Documentation/admin-guide/mm/hugetlbpage.rst.
1894 Note that this parameter only applies to non-gigantic huge pages.
1904 boot-time allocation of gigantic hugepages is skipped.
1929 enabled, those vmemmap pages cannot be optimized even if this
1939 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1945 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1967 Set device-properties for ACPI-enumerated I2C-attached
1968 touchscreen, to e.g. fix coordinates of upside-down
1976 Omit "=<val>" entirely Set a boolean device-property
1977 Unsigned number Set a u32 device-property
1978 Anything else Set a string device-property
1981 i2c_touchscreen_props=GDIX1001:touchscreen-inverted-x:
1982 touchscreen-inverted-y
1984 i2c_touchscreen_props=MSSL1680:touchscreen-size-x=1920:
1985 touchscreen-size-y=1080:touchscreen-inverted-y:
1986 firmware-name=gsl1680-vendor-model.fw:silead,home-button
1991 (disabled by default, and as a pre-condition
1993 i8042.direct [HW] Put keyboard port into non-translated mode
1995 keyboard and cannot control its state
2007 suspend-to-ram transitions, only during s2r
2031 -1 -- never invert brightness
2032 0 -- machine default
2033 1 -- force brightness inversion
2035 ia32_emulation= [X86-64]
2037 When true, allows loading 32-bit programs and executing 32-bit
2059 idle=halt: Halt is forced to be used for CPU idle.
2062 idle=nomwait: Disable mwait for CPU C-states
2090 legacy only accept legacy-NaN binaries, if supported
2092 2008 only accept 2008-NaN binaries, if supported
2103 'relaxed' straps the emulator for both legacy-NaN and
2104 2008-NaN, whereas 'strict' enables legacy-NaN only on
2113 Ignore loglevel setting - this will print /all/
2180 Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" |
2181 "ima-sigv2" }
2182 Default: "ima-ng"
2214 initcall_blacklist= [KNL] Do not execute a comma-separated list of
2215 initcall functions. Useful for debugging built-in
2260 0 -- basic integrity auditing messages. (Default)
2261 1 -- additional integrity auditing messages.
2289 could harm performance of some high-throughput
2298 1 to 9 specify maximum depth of C-state.
2307 algorithms for p-state selection. There are two
2308 P-state selection algorithms provided by
2311 on whether or not the hardware managed P-states
2317 enabling its internal governor). This mode cannot be
2318 used along with the hardware-managed P-states (HWP)
2322 in favor of acpi-cpufreq. Forcing the intel_pstate driver
2323 instead of acpi-cpufreq may disable platform features, such
2325 P-States information being indicated to OSPM and therefore
2328 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
2341 Allow per-logical-CPU P-State performance control limits using
2344 Do not enable capacity-aware scheduling (CAS) on
2347 intremap= [X86-64,Intel-IOMMU,EARLY]
2352 BIOS x2APIC opt-out request will be ignored
2395 AMD Gart HW IOMMU-specific options:
2414 Do scatter-gather (SG) merging. Implies "force"
2418 Don't do scatter-gather (SG) merging.
2431 0 - Try to allocate a 32-bit DMA address first, before
2433 1 - Allocate directly from the full usable range,
2435 greater than 32-bit addressing.
2439 0 - Lazy mode.
2445 1 - Strict mode.
2448 unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
2450 legacy driver-specific options takes precedence.
2455 0 - Use IOMMU translation for DMA.
2456 1 - Bypass the IOMMU for DMA.
2457 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2459 io7= [HW] IO7 for Marvel-based Alpha systems
2474 See Documentation/admin-guide/nfs/nfsroot.rst.
2492 The argument is a cpu list, as described above.
2510 Enables support for pseudo-NMIs in the kernel. This
2521 for it. Also check all handlers each timer
2529 [Deprecated - use cpusets instead]
2530 Format: [flag-list,]<cpu-list>
2553 is irreversible: it's not possible to bring back a CPU to
2560 You can move a process onto or off an "isolated" CPU via
2561 the CPU affinity syscalls or cpuset.
2562 <cpu number> begins at 0 and the maximum value is
2563 "number of CPUs in system - 1".
2570 handled by the kernel and cannot be changed via
2577 interrupts are directed to the housekeeping CPU
2578 so that IO submitted on the housekeeping CPU
2579 cannot disturb the isolated CPU.
2589 The format of <cpu-list> is described above.
2593 ivrs_ioapic [HW,X86-64]
2594 Provide an override to the IOAPIC-ID<->DEVICE-ID
2598 For example, to map IOAPIC-ID decimal 10 to
2604 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2607 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2611 ivrs_hpet [HW,X86-64]
2612 Provide an override to the HPET-ID<->DEVICE-ID
2616 For example, to map HPET-ID decimal 10 to
2622 * To map HPET-ID decimal 0 to PCI device 00:14.0
2625 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2629 ivrs_acpihid [HW,X86-64]
2630 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2634 For example, to map UART-HID:UID AMD0020:0 to
2640 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2643 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2667 the kernel for non-movable allocations. The requested
2677 subsystem. Note that allocations like PTEs-from-HighMem
2685 for non-movable allocations and remaining memory is used
2687 are exclusive, so you cannot specify multiple forms.
2696 gdb or control-c on the dbgp connection. When
2697 not using this parameter you use sysrq-g to break into
2702 or a supported polling keyboard driver (non-usb).
2729 Configure the RouterBoard 532 series on-chip
2732 kmemleak= [KNL,EARLY] Boot-time kmemleak enable/disable
2738 kprobe_event=[probe-list]
2740 The probe-list is a semicolon delimited list of probe
2770 execution by eliminating the write-protection faults
2797 virtualization on-demand when creating and destroying
2805 is that doing so may interfere with using out-of-tree
2832 back to huge pages. If the value is a non-zero N, KVM will
2837 kvm-amd.nested= [KVM,AMD] Control nested virtualization feature in
2840 kvm-amd.npt= [KVM,AMD] Control KVM's use of Nested Page Tables,
2841 a.k.a. Two-Dimensional Page Tables. Default is 1
2845 kvm-arm.mode=
2851 nvhe: Standard nVHE-based mode, without support for
2858 nested: VHE-based mode with support for nested
2866 command-line.
2870 kvm-arm.vgic_v3_group0_trap=
2871 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-0
2874 kvm-arm.vgic_v3_group1_trap=
2875 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-1
2878 kvm-arm.vgic_v3_common_trap=
2882 kvm-arm.vgic_v4_enable=
2886 kvm-arm.wfe_trap_policy=
2889 CPU architecture.
2895 kvm-arm.wfi_trap_policy=
2898 CPU architecture.
2912 kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables,
2913 a.k.a. Two-Dimensional Page Tables. Default is 1
2917 kvm-intel.emulate_invalid_guest_state=
2919 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2925 kvm-intel.flexpriority=
2930 kvm-intel.nested=
2934 kvm-intel.unrestricted_guest=
2940 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2941 CVE-2018-3620.
2952 kvm-intel.vpid= [KVM,Intel] Control KVM's use of Virtual Processor
2960 Certain CPUs are vulnerable to an exploit against CPU
2972 on - enable the interface for the mitigation
2978 enabled and cannot be disabled.
3037 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
3043 lapic [X86-32,APIC,EARLY] Enable the local APIC even if BIOS
3047 value for LAPIC timer one-shot implementation. Default
3048 back to the programmable timer unit in the LAPIC.
3051 lapic_timer_c2_ok [X86,APIC,EARLY] trust the local apic timer
3070 libata.force= [LIBATA] Force configurations. The format is a comma-
3082 first fan-out link behind PMP device. It does not
3096 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
3103 * rstonce: only attempt one reset during hot-unplug
3146 * external: Mark port as external (hotplug-capable).
3200 Specify the number of self-propagating call_rcu()
3208 occasional long-duration lock hold time. Defaults
3219 Set the number of locking read-acquisition kthreads.
3224 Set the number of locking write-acquisition kthreads.
3227 Set time (s) after boot for CPU-hotplug testing.
3230 Set time (s) between CPU-hotplug operations, or
3231 zero to disable CPU-hotplug testing.
3234 Do periodic testing of real-time lock priority
3239 non-real-time spinlocks, due to their disabling
3240 of preemption. Note that non-realtime mutexes
3253 Set task-shuffle interval (jiffies). Shuffling
3254 tasks allows some CPUs to go into dyntick-idle
3259 is useful for hands-off automated testing.
3278 Run the write-side locktorture kthreads at
3279 sched_set_fifo() real-time priority.
3297 7 (KERN_DEBUG) debug-level messages
3309 logo.nologo [FB] Disables display of the built-in Linux logo.
3327 an IEEE 1284-compliant printer is attached; if
3333 time-consuming boot-time autodetection (up to 250 ms per
3334 CPU). 0 enables autodetection (default). To determine
3353 Example: machtype=lemote-yeeloong-2f-7inch
3358 bootup you can bring up the other plugged cpu by executing
3359 "echo 1 > /sys/devices/system/cpu/cpuX/online". So maxcpus
3365 (loop.max_loop) unconditionally pre-created at init time. The default
3368 devices can be requested on-demand with the
3369 /dev/loop-control interface.
3371 mce= [X86-{32,64}]
3396 polling timer and CMCI. All events reported as
3404 and you cannot deactivate the agent, then this option
3408 do not opt-in to Local MCE delivery. Use legacy method
3429 don't overwrite the bios-set CMCI threshold. This boot
3438 force-enable recoverable machine check code paths
3444 See Documentation/admin-guide/md.rst.
3451 Control mitigation for the Micro-architectural Data
3454 Certain CPUs are vulnerable to an exploit against CPU
3466 full - Enable MDS mitigation on vulnerable CPUs
3467 full,nosmt - Enable MDS mitigation and disable
3469 off - Unconditionally disable MDS mitigation
3471 On TAA-affected machines, mds=off can be prevented by
3480 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3495 [ARC,MICROBLAZE] - the limit applies only to low memory,
3498 [ARM64] - only limits memory covered by the linear
3511 [ARM,MIPS,EARLY] - override the memory layout
3518 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3525 per-device physically contiguous DMA buffers.
3533 See Documentation/admin-guide/mm/memory-hotplug.rst.
3558 Example: Exclude memory from 0x18690000-0x1869ffff
3572 memmap=<size>%<offset>-<oldtype>+<newtype>
3574 from <oldtype> to <newtype>. If "-<oldtype>" is left
3589 repeatable BIOS-originated corruption always
3609 those vmemmap pages cannot be optimized even
3633 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3639 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
3643 s2idle - Suspend-To-Idle
3644 shallow - Power-On Suspend or equivalent (if supported)
3645 deep - Suspend-To-RAM or equivalent (if supported)
3646 See Documentation/admin-guide/pm/sleep-states.rst.
3648 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
3664 0 - The attached screen is the 3.5" TFT
3665 1 - The attached screen is the 7" TFT
3666 2 - The VGA Shield is attached (1024x768)
3670 b - Enable backlight. The TFT backlight pin will be
3674 c - Enable the s3c camera interface.
3675 t - Reserved for enabling touchscreen support. The
3679 https://repo.or.cz/w/linux-2.6/mini2440.git
3683 CPU vulnerabilities. This is a set of curated,
3684 arch-independent options, each of which is an
3685 aggregation of existing arch-specific options.
3691 Disable all optional CPU mitigations. This
3693 expose users to several CPU vulnerabilities.
3714 ssbd=force-off [ARM64]
3723 Mitigate all CPU vulnerabilities, but leave SMT
3727 have other ways of avoiding SMT-based attacks.
3731 Mitigate all CPU vulnerabilities, disabling SMT
3755 the same CPU buffers as affected by MDS and TAA.
3757 is to clear the affected CPU buffers.
3762 full - Enable mitigation on vulnerable CPUs
3764 full,nosmt - Enable mitigation and disable SMT on
3767 off - Unconditionally disable mitigation
3780 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3810 module_blacklist= [KNL] Do not load a comma-separated list of
3835 movable_node [KNL,EARLY] Boot-time switch to make hotplugable memory
3842 Format: <name>,<region-number>,<size>,<offset>
3845 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3884 something different and driver-specific.
3924 [NFS] enable 64-bit inode numbers.
3925 If zero, the NFS client will fake up a 32-bit inode
3927 of returning the full 64-bit number.
3928 The default is to return 64-bit inode numbers.
3963 [NFS4] Specify an additional fixed unique ident-
3994 driver. A non-zero value sets the minimum interval
3999 server-to-server copies for which this server is
4011 server-to-server copy, knfsd temporarily mounts
4018 See Documentation/admin-guide/nfs/nfsroot.rst.
4020 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
4021 See Documentation/admin-guide/nfs/nfsroot.rst.
4024 See Documentation/admin-guide/nfs/nfsroot.rst.
4028 NMI stack-backtrace request.
4037 0 - turn hardlockup detector in nmi_watchdog off
4038 1 - turn hardlockup detector in nmi_watchdog on
4039 rNNN - configure the watchdog with raw perf event 0xNNN
4052 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
4056 no4lvl [RISCV,EARLY] Disable 4-level and 5-level paging modes.
4057 Forces kernel to use 3-level paging instead.
4059 no5lvl [X86-64,RISCV,EARLY] Disable 5-level paging mode. Forces
4060 kernel to use 4-level paging instead.
4067 noapictimer [APIC,X86] Don't set up the APIC timer
4095 no_entry_flush [PPC,EARLY] Don't flush the L1-D cache when entering the kernel.
4097 noexec32 [X86-64]
4098 This affects only 32-bit executables.
4099 noexec32=on: enable non-executable mappings (default)
4101 noexec32=off: disable non-executable mappings
4112 nofxsr [BUGS=X86-32] Disables x86 floating point extended
4114 legacy floating-point registers on task switch.
4127 compared. However, if this command-line option is
4144 nohpet [X86] Don't use the HPET timer.
4155 The argument is a cpu list, as described above.
4158 whenever possible. The boot CPU will be forced outside
4170 nointremap [X86-64,Intel-IOMMU,EARLY] Do not enable interrupt
4172 [Deprecated - use intremap=off]
4174 noinvpcid [X86,EARLY] Disable the INVPCID cpu feature.
4178 noirqdebug [X86-32] Disables the code which attempts to detect and
4188 no-kvmapf [X86,KVM,EARLY] Disable paravirtualized asynchronous page
4191 no-kvmclock [X86,KVM,EARLY] Disable paravirtualized KVM clock driver
4193 nolapic [X86-32,APIC,EARLY] Do not enable or use the local APIC.
4195 nolapic_timer [X86-32,APIC,EARLY] Do not use the local APIC timer.
4197 nomce [X86-32] Disable Machine Check Exception
4199 nomfgpt [X86-32] Disable Multi-Function General Purpose
4200 Timer usage (for AMD Geode machines).
4205 not load if they could possibly displace the pre-
4208 perform display-mode changes or accelerated rendering.
4221 nopcid [X86-64,EARLY] Disable the PCID cpu feature.
4223 nopku [X86] Disable Memory Protection Keys CPU feature found
4226 nopti [X86-64,EARLY]
4242 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
4248 no-scroll [VGA] Disables scrollback.
4249 This is required for the Braillex ib80-piezo Braille
4252 nosgx [X86-64,SGX,EARLY] Disables Intel SGX kernel support.
4269 nosmt=force: Force disable SMT, cannot be undone
4272 nosoftlockup [KNL] Disable the soft-lockup detector.
4278 nospectre_bhb [ARM64,EARLY] Disable all mitigations for Spectre-BHB (branch
4291 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,LOONGARCH,EARLY]
4298 timer IRQ sources, i.e., the IO-APIC timer. This can
4299 work around problems with incorrect timer
4303 [PPC,EARLY] Don't flush the L1-D cache after accessing user data.
4316 no-vmw-sched-clock
4321 soft-lockup and NMI watchdog (hard-lockup).
4325 nox2apic [X86-64,APIC,EARLY] Do not enable x2APIC mode.
4333 enabling legacy floating-point and sse state.
4353 number of already plugged CPU during bootup, later in
4354 runtime you can physically add extra cpu until it reaches
4355 n. So during boot up some boot time memory for per-cpu
4356 variables need be pre-allocated for later physical cpu
4383 soft-reserved memory partitioning.
4392 See Documentation/admin-guide/sysctl/vm.rst for details.
4395 See Documentation/core-api/debugging-via-ohci1394.rst for more
4410 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4414 boundary - index of last SLC block on Flex-OneNAND.
4416 lock - Configure if Flex-OneNAND boundary should be locked.
4417 Once locked, the boundary cannot be changed.
4435 page_owner= [KNL,EARLY] Boot-time page_owner enabling option.
4441 page_poison= [KNL,EARLY] Boot-time parameter changing the state of
4469 See Documentation/admin-guide/tainted-kernels.rst for
4480 bit 2: print timer info
4522 Set to non-zero to probe primary and secondary ISA
4528 Set to non-zero if a chip is present that snoops speed
4576 Set to non-zero to probe tertiary and further ISA
4592 Set to non-zero to probe QDI controllers. By default
4597 Set to non-zero to probe Winbond controllers. Use
4644 bios [X86-32] force use of PCI BIOS, don't access
4646 has a non-standard PCI host bridge.
4647 nobios [X86-32] disallow use of PCI BIOS, only direct
4653 data in IO port 0xCFC, both 32-bit).
4655 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4656 the function, IO port 0xCFA, also 8-bit, sets
4658 through ports 0xC000-0xCFFF).
4665 root domains (aka PCI segments, in ACPI-speak).
4670 config space on AMD family 10h CPU
4673 disable the use of MSI interrupts system-wide.
4678 primary IO-APIC for bridges that cannot disable
4683 a chipset where boot IRQs cannot be disabled.
4685 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4709 F0000h-100000h range.
4714 assign-busses [X86] Always assign all PCI bus
4735 <linux-pci@vger.kernel.org>.
4739 a bug to <linux-pci@vger.kernel.org>.
4751 bfsort Sort PCI devices into breadth-first order.
4754 nobfsort Don't sort PCI devices into breadth-first order.
4756 tuning and use the BIOS-configured MPS defaults.
4766 configuration allows peer-to-peer DMA between
4769 that hot-added devices will work.
4784 A PCI-PCI bridge can be specified if resource
4790 for 4096-byte alignment.
4792 end-to-end CRC checking). Only effective if
4823 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4854 bit-0 : ACS Source Validation
4855 bit-1 : ACS Translation Blocking
4856 bit-2 : ACS P2P Request Redirect
4857 bit-3 : ACS P2P Completion Redirect
4858 bit-4 : ACS Upstream Forwarding
4859 bit-5 : ACS P2P Egress Control
4860 bit-6 : ACS Direct Translated P2P
4870 Validation unchanged from whatever power-up
4882 system-wide.
4896 dpc-native Use native PCIe service for DPC only. May
4913 Keep all power-domains already enabled by bootloader on,
4931 pirq= [SMP,APIC] Manual mp-table setup
4932 See Documentation/arch/x86/i386/IO-APIC.rst.
4936 See also Documentation/admin-guide/parport.rst.
4955 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4964 { on | off | curr | res | no-curr | no-res }
4994 function to NULL. On Idle the CPU just reduces
5009 none - Limited to cond_resched() calls
5010 voluntary - Limited to cond_resched() and might_sleep() calls
5011 full - Any section that isn't explicitly preempt disabled
5015 lazy - Scheduler controlled. Similar to full but instead
5021 print-fatal-signals=
5027 coredump - etc.
5030 you might want to try "ulimit -i unlimited".
5042 or lockdep-detected issues (only if lock debug is on).
5050 Allows storing messages from non-panic CPUs into
5052 flushed to consoles by the panic-CPU on
5053 a best-effort basis.
5059 on - unlimited logging to /dev/kmsg from userspace
5060 off - logging to /dev/kmsg disabled
5061 ratelimit - ratelimit the logging
5072 - 'always': traditional behavior always allows mem overrides.
5073 - 'ptrace': only allow mem overrides for active ptracers.
5074 - 'never': never allow mem overrides.
5078 Limit processor to maximum C-state
5082 Ignore the _CST method to determine C-states,
5089 Param: "schedule" - profile schedule points.
5090 Param: "kvm" - profile VM exits.
5091 Param: <number> - step/bucket size as a power of 2 for
5122 pti= [X86-64] Control Page Table Isolation of user and
5127 on - unconditionally enable
5128 off - unconditionally disable
5129 auto - kernel detects whether your CPU model is
5135 [KNL] Number of legacy pty's. Overwrites compiled-in
5147 See Documentation/admin-guide/md.rst.
5150 See Documentation/admin-guide/blockdev/ramdisk.rst.
5155 [KNL,EARLY] Disable trusting the use of the CPU's
5169 cross-syscall address exposures. This is only
5175 ras=option[,option,...] [KNL] RAS-specific options
5181 rcu_nocbs[=cpu-list]
5182 [KNL] The optional argument is a cpu list,
5186 enable the no-callback CPU mode, which prevents
5191 "p" for RCU-preempt, "s" for RCU-sched, and "g"
5193 "N" is the CPU number. This reduces OS jitter on
5195 and real-time workloads. It can also improve
5199 list of CPUs is set to no-callback mode from boot.
5202 arguments are omitted, no CPU will be set to
5203 no-callback mode from boot but the mode may be
5214 This improves the real-time response for the
5216 wake up the corresponding kthread, but degrades
5218 periodically wake up to do the polling.
5225 Do only a one-line RCU CPU stall warning when
5226 there is an ongoing too-long CSD-lock wait.
5232 If triggered before the RCU grace-period machinery
5242 RCU grace-period cleanup.
5246 RCU grace-period initialization.
5250 RCU grace-period pre-initialization, that is,
5251 the propagation of recent CPU-hotplug changes up
5255 Set delay from grace-period initialization to
5268 soliciting quiescent-state help from
5280 Set the SCHED_FIFO priority of the RCU per-CPU
5283 and for the RCU grace-period kthreads (rcu_bh,
5285 set, valid values are 1-99 and the default is 1
5286 (the least-favored priority). Otherwise, when
5287 RCU_BOOST is not set, valid values are 0-99 and
5288 the default is zero (non-realtime operation).
5293 On callback-offloaded (rcu_nocbs) CPUs,
5296 use of the ->nocb_bypass list. However, in the
5297 common non-flooded case, RCU queues directly to
5298 the main ->cblist in order to avoid the extra
5299 overhead of the ->nocb_bypass list and its lock.
5301 a single jiffy, RCU pre-queues the callbacks into
5302 the ->nocb_bypass queue. The definition of "too
5306 On callback-offloaded (rcu_nocbs) CPUs, avoid
5319 batch limiting is re-enabled.
5323 RCU's force-quiescent-state scan will aggressively
5331 Set the page-cache refill delay (in milliseconds)
5332 in response to low-memory conditions. The range
5336 Set the shift-right count to use to compute
5337 the callback-invocation batch limit bl from
5338 the number of callbacks queued on this CPU.
5342 order to allow the CPU to do other work.
5344 Please note that this callback-invocation batch
5345 limit applies only to non-offloaded callback
5354 cache-to-cache transfer latencies.
5360 and for NUMA systems with large remote-access
5366 maintained per one CPU. Object size is equal
5376 the wakeup overhead on the global grace-period
5378 each group's NOCB grace-period kthread.
5381 Cause the grace-period kthread to get an extra
5383 it should at force-quiescent-state time.
5396 this specifies an rcu_read_unlock()-time delay
5400 of RCU-protected pointers after the relevant
5410 per-CPU rcuc kthreads. Defaults to a non-zero
5439 grace-period primitives such as call_rcu().
5450 grace-period primitives.
5453 Set test-start holdoff period. The purpose of
5471 Test the double-argument variant of kfree_rcu().
5473 rcuscale.kfree_rcu_test_single, both the single-
5474 and double-argument variants are tested.
5477 Test the single-argument variant of kfree_rcu().
5479 rcuscale.kfree_rcu_test_double, both the single-
5480 and double-argument variants are tested.
5494 does not affect the data-collection interval,
5496 like CPU consumption.
5499 Set number of RCU readers. The value -1 selects
5501 "n" less than -1 selects N-n+1, where N is again
5502 the number of CPUs. For example, -2 selects N
5503 (the number of CPUs), -3 selects N+1, and so on.
5504 A value of "n" less than or equal to -N selects
5517 complete. This is useful for hands-off automated
5524 Write-side holdoff between grace periods,
5529 Additional write-side holdoff between grace
5547 for RCU grace-period forward-progress testing
5554 Specify the fraction of a CPU-stall-warning
5555 period to do tight-loop forward-progress testing.
5559 forward-progress tests.
5563 need_resched() during tight-loop forward-progress
5567 Use conditional/asynchronous update-side
5568 normal-grace-period primitives, if available.
5571 Use conditional/asynchronous update-side
5572 expedited-grace-period primitives, if available.
5575 Use conditional/asynchronous update-side
5576 normal-grace-period primitives that also take
5581 Use conditional/asynchronous update-side
5582 expedited-grace-period primitives that also take
5606 Use expedited update-side primitives, if available.
5609 Use normal (non-expedited) asynchronous
5610 update-side primitives, if available.
5613 Use polled update-side normal-grace-period
5617 Use polled update-side expedited-grace-period
5621 Use polled update-side normal-grace-period
5626 Use polled update-side expedited-grace-period
5650 Use normal (non-expedited) synchronous
5651 update-side primitives, if available. If all
5655 they are all non-zero.
5659 accurately, from a timer handler. Not all RCU
5663 Leak an RCU-protected pointer out of the reader.
5678 Set number of RCU callback-offload togglers.
5683 callback-offload toggling attempts.
5686 Set number of RCU readers. The value -1 selects
5687 N-1, where N is the number of CPUs. A value
5688 "n" less than -1 selects N-n-2, where N is again
5689 the number of CPUs. For example, -2 selects N
5690 (the number of CPUs), -3 selects N+1, and so on.
5693 Enable debug-object double-call_rcu() testing.
5696 Set time (s) after boot for CPU-hotplug testing.
5699 Set time (jiffies) between CPU-hotplug operations,
5700 or zero to disable CPU-hotplug testing.
5704 by a high-priority FIFO real-time task. Set to
5713 second) between preemptions by a high-priority
5714 FIFO real-time task. This delay is mediated
5719 The number of times in a given read-then-exit
5720 episode that a set of read-then-exit kthreads
5725 read-then-exit testing episodes.
5730 are entered from low-order bit up, and are
5732 0x1 bit is normal readers, 0x2 NMI-safe readers,
5733 and 0x4 light-weight readers.
5736 Set task-shuffle interval (s). Shuffling tasks
5737 allows some CPUs to go into dyntick-idle mode
5742 is useful for hands-off automated testing.
5745 Duration of CPU stall (s) to test RCU CPU stall
5751 any other stall-related activity. Note that
5754 cause the CPU to pass through a quiescent state.
5756 RCU CPU stall warnings, but will instead result
5757 in scheduling-while-atomic splats.
5776 grace-period kthread to test RCU CPU stall
5779 kthread is starved first, then the CPU.
5800 of RCU priority-boost testing. Defaults to zero,
5807 Test RCU's dyntick-idle handling. See also the
5817 Dump ftrace buffer after reporting RCU CPU
5821 Provide RCU CPU stall notifiers, but see the
5827 Suppress RCU CPU stall warning messages.
5830 Suppress RCU CPU stall warning messages and
5836 Set timeout for RCU CPU stall warning messages.
5841 Set timeout for expedited RCU CPU stall warning
5845 adjusted to an arch timer tick resolution.
5859 expedited RCU CPU stall warning.
5862 Use expedited grace-period primitives, for
5865 but can increase CPU utilization, degrade
5866 real-time latency, and degrade energy efficiency.
5870 Use only normal grace-period primitives,
5873 real-time latency, CPU utilization, and
5875 increased grace-period latency. This parameter
5882 only normal grace-period primitives. No effect
5888 post-boot attempt at an expedited RCU grace
5889 period to instead use normal non-expedited
5890 grace-period processing.
5898 set to the default value of -1.
5901 Set the minimum number of callback-queuing-time
5902 lock-contention events per jiffy required to
5903 cause the RCU Tasks flavors to switch to per-CPU
5906 the default value of -1.
5911 of -1 allows this to be automatically (and
5919 number avoids disturbing real-time workloads,
5923 Number of callbacks on a given CPU that will
5924 cancel laziness on that CPU. Use -1 to disable
5934 only printed prior to the stall-warning message
5982 force - Override the decision by the kernel to hide the
6015 Use the CPU reboot vector for warm reset
6021 There are some built-in platform specific "quirks"
6022 - you may see: "reboot: <name> series board detected.
6026 built-in quirk table, and use the generic default
6059 Set test-start holdoff period. The purpose of
6074 but the default has already reduced the per-pass
6079 Set number of readers. The default value of -1
6088 Set the read-side critical-section duration,
6092 Specify the read-protection implementation to test.
6118 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
6148 reservetop= [X86-32,EARLY]
6165 See Documentation/power/swsusp-and-swap-files.rst
6181 AMD-based UNRET and IBPB mitigations alone do not stop
6183 sibling threads. For that reason, STIBP is used on pro-
6187 off - no mitigation
6188 auto - automatically select a migitation
6189 auto,nosmt - automatically select a mitigation,
6193 ibpb - On AMD, mitigate short speculation
6198 ibpb,nosmt - Like "ibpb" above but will disable SMT
6202 unret - Force enable untrained return thunks,
6203 only effective on AMD f15h-f17h based
6205 unret,nosmt - Like unret, but will disable SMT when STIBP
6210 time according to the CPU.
6237 ro [KNL] Mount root device read-only on boot
6240 on Mark read-only kernel memory as read-only (default).
6241 off Leave read-only kernel memory writable for debugging.
6242 full Mark read-only kernel memory and aliases as read-only
6249 debug-uart get routed to the D+ and D- pins of the usb
6255 block/early-lookup.c for details.
6280 rw [KNL] Mount root device read-write on boot
6334 to 10 seconds for built-in smp_call_function()
6341 that requesting even small non-zero numbers of
6342 seconds can result in RCU CPU stall warnings,
6348 The default of -1 specifies a number of kthreads
6353 test before initiating CPU-hotplug operations.
6357 CPU-hotplug operations. Specifying zero (which
6358 is the default) disables CPU-hotplug operations.
6364 Non-zero values are useful for automated tests.
6377 preempt_disable() to disable CPU hotplug
6387 "wait" parameter. A value of -1 selects the
6388 default if all other weights are -1. However,
6390 value of -1 will instead select a weight of zero.
6395 non-zero "wait" parameter. See weight_single.
6408 non-zero "wait" parameter. See weight_single
6420 non-zero "wait" parameter. See weight_single
6427 skew_tick= [KNL,EARLY] Offset the periodic timer tick per cpu to mitigate
6431 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
6432 1 -- enable.
6443 0 -- disable.
6444 1 -- enable.
6447 serialnumber [BUGS=X86-32]
6449 sev=option[,option...] [X86-64]
6455 Do not enable SEV-SNP (applies to host/hypervisor
6458 SEV-SNP guests.
6466 to set it to "all" by meaning -- no limit here.
6541 for a CPU to release the CSD lock. This is
6547 using the csdlock_debug- kernel parameter.
6552 system. By default, let CSD-lock acquisition
6554 for this value provides a 5-minute timeout.
6556 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
6557 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
6558 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
6559 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
6560 smsc-ircc2.ircc_irq= [HW] IRQ line
6561 smsc-ircc2.ircc_dma= [HW] DMA channel
6562 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
6568 (logical CPUs) to use per physical CPU on systems
6572 Default: -1 (no limit)
6575 [KNL] Should the soft-lockup detector generate panics.
6578 A value of 1 instructs the soft-lockup detector
6579 to panic the machine when a soft-lockup occurs. It is
6582 respective build-time switch to that functionality.
6585 [KNL] Should the soft-lockup detector generate
6590 See Documentation/admin-guide/laptops/sonypi.rst
6597 on - (default) Enable the HW or SW mitigation as
6600 vmexit - On systems which don't have the HW mitigation
6603 protected from VM-originated BHI attacks, but
6605 off - Disable the mitigation.
6612 on - unconditionally enable, implies
6614 off - unconditionally disable, implies
6616 auto - kernel detects whether your CPU model is
6621 CPU, the available microcode, the setting of the
6635 retpoline - replace indirect branches
6636 retpoline,generic - Retpolines
6637 retpoline,lfence - LFENCE; indirect branch
6638 retpoline,amd - alias for retpoline,lfence
6639 eibrs - Enhanced/Auto IBRS
6640 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
6641 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
6642 ibrs - use IBRS to protect kernel
6652 on - Unconditionally enable mitigations. Is
6655 off - Unconditionally disable mitigations. Is
6658 prctl - Indirect branch speculation is enabled,
6664 - Like "prctl" above, but only STIBP is
6670 - Same as "prctl" above, but all seccomp
6675 - Like "seccomp" above, but only STIBP is
6680 auto - Kernel selects the mitigation depending on
6681 the available CPU features and vulnerability.
6691 off - Disable mitigation
6692 microcode - Enable microcode mitigation only
6693 safe-ret - Enable sw-only safe RET mitigation (default)
6694 ibpb - Enable mitigation by issuing IBPB on
6696 ibpb-vmexit - Issue IBPB only on VMEXIT
6697 (cloud-specific mitigation)
6722 on - Unconditionally disable Speculative Store Bypass
6723 off - Unconditionally enable Speculative Store Bypass
6724 auto - Kernel detects whether the CPU model contains an
6727 CPU is not vulnerable, "off" is selected. If the
6728 CPU is vulnerable the default mitigation is
6730 prctl - Control Speculative Store Bypass per thread
6734 seccomp - Same as "prctl" above, but all seccomp threads
6742 on,auto - On Power8 and Power9 insert a store-forwarding
6746 off - No action.
6760 off - not enabled
6762 warn - the kernel will emit rate-limited warnings
6770 fatal - the kernel will send SIGBUS to applications
6775 ratelimit:N -
6795 Certain CPUs are vulnerable to an MDS-like
6815 This kernel-boot parameter defaults to 128,
6816 but takes effect only when the low-order four
6833 instead of the compile-time CONFIG_NR_CPUS.
6837 grace-period sequence counter wrap for the
6838 srcu_data structure's ->srcu_gp_seq_needed field.
6853 Specifies the number of no-delay instances
6860 Specifies the per-grace-period phase, number of
6861 non-sleeping polls of readers. Beyond this limit,
6867 Specifies number of microseconds of non-sleeping
6868 delay between each non-sleeping poll of readers.
6871 Specifies the number of update-side contention
6876 set for contention-based conversions to occur.
6886 force-on: Unconditionally enable mitigation for
6888 force-off: Unconditionally disable mitigation for
6911 stacktrace_filter=[function-list]
6913 will trace at boot up. function-list is a comma-separated
6921 Set the STI (builtin display/keyboard on the HP-PARISC
6923 as the initial boot-console.
6975 Note: this parameter cannot be changed while the
6981 percpu one pool for each CPU
6983 to global on non-NUMA machines)
7008 <int> -- Number of I/O TLB slabs
7009 <int> -- Second integer after comma. Number of swiotlb
7012 force -- force using of bounce buffers even if they
7014 noforce -- Never use bounce buffers (for debugging)
7024 later by a loaded module cannot be set this way.
7029 Ignore sysrq setting - this boot parameter will
7037 cache size. See Documentation/networking/ip-sysctl.rst
7044 Specify "mem" (for Suspend-to-RAM) or "standby" (for
7049 wakeup-capable RTC alarm.
7055 -1: disable all active trip points in all thermal zones
7059 -1: disable all critical trip points in all thermal zones
7066 -1: disable all passive trip points
7072 <deci-seconds>: poll all this frequency
7076 Format: <size>[KMG],<size>[KMG]:<state>;<size>[KMG]-<size>[KMG]:<state>
7081 See Documentation/admin-guide/mm/transhuge.rst for more
7089 Format: <size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy>
7095 See Documentation/admin-guide/mm/transhuge.rst for more
7100 Specify if the kernel should make use of the cpu
7107 Prevent the CPU-hotplug component of torturing
7111 Dump the ftrace buffer at torture-test shutdown,
7115 with rotating-rust storage.
7120 disables verbose-printk() sleeping.
7123 Duration of each verbose-printk() sleep in jiffies.
7148 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
7182 [FTRACE] will set tracing buffer size on each cpu.
7186 local - Use the per CPU time stamp counter
7190 global - Event time stamps are synchronize across
7193 counter - Simple counting of events (1, 2, ..)
7197 uptime - Use jiffies as the time stamp.
7198 perf - Use the same clock that perf uses.
7199 mono - Use ktime_get_mono_fast_ns() for time stamps.
7200 mono_raw - Use ktime_get_raw_fast_ns() for time
7202 boot - Use ktime_get_boot_fast_ns() for time stamps.
7206 trace_event=[event-list]
7208 to facilitate early boot debugging. The event-list is a
7209 comma-separated list of trace events to enable. See
7220 trace_instance=[instance-info]
7245 traceoff - Have the tracing instance tracing disabled after it is created.
7246 traceprintk - Have trace_printk() write into this trace instance
7259 memory at 0x284500000 that is 12Megs. The per CPU buffers of that
7293 trace_options=[option-list]
7295 The option-list is a comma delimited list of options
7309 trace_trigger=[trigger-list]
7355 See Documentation/admin-guide/mm/transhuge.rst
7362 See Documentation/admin-guide/mm/transhuge.rst
7369 See Documentation/admin-guide/mm/transhuge.rst
7377 - "tpm"
7378 - "tee"
7379 - "caam"
7380 - "dcp"
7390 - "kernel"
7391 - the same value as trusted.source: "tpm" or "tee"
7392 - "default"
7413 high-resolution timer mode on older hardware, and in
7426 [x86] recalibrate: force recalibration against a HW timer
7427 (HPET or PM timer) on systems whose TSC frequency was
7431 which to check other HW timers (HPET or PM timer), but
7449 on - Enable TSX on the system. Although there are
7452 several previous speculation-related CVEs, and
7456 off - Disable TSX on the system. (Note that this
7464 auto - Disable TSX if X86_BUG_TAA is present,
7469 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7475 Similar to Micro-architectural Data Sampling (MDS)
7478 exploit against CPU internal buffers which can forward
7490 full - Enable TAA mitigation on vulnerable CPUs
7493 full,nosmt - Enable TAA mitigation and disable SMT on
7495 is not disabled because CPU is not
7496 vulnerable to cross-thread TAA attacks.
7497 off - Unconditionally disable TAA mitigation
7499 On MDS-affected machines, tsx_async_abort=off can be
7511 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7517 See also Documentation/input/devices/joystick-parport.rst
7519 udbg-immortal [PPC] When debugging early kernel crashes that
7525 Set number of hash buckets for UDP/UDP-Lite connections
7527 uhci-hcd.ignore_oc=
7529 Some badly-designed motherboards generate lots of
7554 unwind_debug [X86-64,EARLY]
7562 (default -1 = authorized (same as 1),
7568 for newly-detected USB devices (default 2). This
7596 [USB] Specifies timeout for the initial 64-byte
7603 [USB] A list of quirk entries to augment the built-in
7606 VendorID:ProductID:Flags. The IDs are 4-digit hex
7608 will change the built-in quirk; setting it if it is
7613 a 255-byte read);
7617 Set-Interface requests);
7636 (bInterval-1).
7674 usb-storage.delay_use=
7681 usb-storage.quirks=
7683 override the built-in unusual_devs list. List
7686 and Product ID values (4-digit hex numbers) and
7688 to a common usb-storage quirk flag as follows:
7730 medium is write-protected).
7739 1 - undefined instruction events
7740 2 - system calls
7741 4 - invalid data aborts
7742 8 - SIGSEGV faults
7743 16 - SIGBUS faults
7752 vdso32= [X86] Control the 32-bit vDSO
7753 vdso32=1: enable 32-bit VDSO
7754 vdso32=0 or vdso32=2: disable 32-bit VDSO
7764 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
7795 vga= [BOOT,X86-32] Select a particular video mode
7797 Documentation/admin-guide/svga.rst.
7812 - Disable all of the above options
7836 vsyscall= [X86-64,EARLY]
7839 code). Most statically-linked binaries and older
7863 see vga-softcursor.rst. Default: 2 = underline.
7868 This is a 16-member array composed of values
7869 ranging from 0-255.
7874 This is a 16-member array composed of values
7875 ranging from 0-255.
7880 This is a 16-member array composed of values
7881 ranging from 0-255.
7886 Set system-wide default UTF-8 mode for all tty's.
7887 Default is 1, i.e. UTF-8 mode is enabled for all
7892 Format=<-1|0|1>
7893 Set system-wide default for whether a cursor
7894 is shown on new VTs. Default is -1,
7899 vt.italic= [VT] Default color for italic text; 0-15.
7902 vt.underline= [VT] Default color for underlined text; 0-15.
7906 see Documentation/watchdog/watchdog-parameters.rst
7907 or other driver-specific files in the
7921 Format: <cpu-list>
7942 Per-cpu work items which run for longer than this
7943 threshold are automatically considered CPU intensive
7945 them from noticeably delaying other per-cpu work
7963 Per-cpu workqueues are generally preferred because
7965 locality; unfortunately, per-cpu workqueues tend to
7968 Enabling this makes the per-cpu workqueues which
7979 workqueues. Can be one of "cpu", "smt", "cache",
7982 Documentation/core-api/workqueue.rst.
7991 items queued without explicit CPU specified are put
7992 on the local CPU. This guarantee is no longer true
7993 and while local CPU is still preferred work items
7995 forces round-robin CPU selection to flush out
8003 on - Enable writecombine, use WUC for ioremap_wc()
8004 off - Disable writecombine, use SUC for ioremap_wc()
8006 x2apic_phys [X86-64,APIC,EARLY] Use x2apic physical mode instead of
8010 xen_512gb_limit [KNL,X86-64,XEN]
8020 ide-disks -- unplug primary master IDE devices
8021 aux-ide-disks -- unplug non-primary-master IDE devices
8022 nics -- unplug network devices
8023 all -- unplug all emulated devices (NICs and IDE disks)
8024 unnecessary -- unplugging emulated devices is
8027 never -- do not unplug even if version check succeeds
8041 Select whether to always use non-faulting (safe) MSR
8061 xen_timer_slop= [X86-64,XEN,EARLY]
8062 Set the timer slop (in nanoseconds) for the virtual Xen
8065 improve timer resolution at the expense of processing
8066 more timer interrupts.
8086 preferred over the 2-level event handling, as it is
8103 xive.store-eoi=off [PPC]
8109 xhci-hcd.quirks [USB,KNL]