Lines Matching +full:no +full:- +full:tick +full:- +full:in +full:- +full:suspend
7 accepted. In most cases the overhead is negligible.
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 nospcr -- disable console in ACPI SPCR table as
41 If set to vendor, prefer vendor-specific driver
66 debug output. Bits in debug_layer correspond to a
67 _COMPONENT in an ACPI source file, e.g.,
69 Bits in debug_level correspond to a level in
73 Documentation/firmware-guide/acpi/debug.rst for more information about
89 { strict | lax | no }
92 only). IO ports and memory declared in ACPI might be
93 used by the ACPI subsystem in arbitrary AML code and
101 no: ACPI OperationRegions are not marked as reserved,
102 no further checks are performed.
111 default in APIC mode
115 default in PIC mode
126 by unsupported hardware/firmware features can result in
131 Format: <byte> or <bitmap-list>
134 Disable auto-serialization of AML methods
137 auto-serialization feature.
146 By default, SSDTs contained in the RSDT/XSDT will be
155 Ignore the ACPI-based watchdog interface (WDAT) and let
169 be necessary to carry out a cold reboot _twice_ in a
176 acpi_osi=! # disable all built-in OS vendor
178 acpi_osi=!! # enable all built-in OS vendor
182 'acpi_osi=!' can be used in combination with single or
197 'acpi_osi=' cannot be used in combination with other
199 exist in the ACPI namespace. NOTE that such command can
207 'acpi_osi=!*' can be used in combination with single or
240 For broken nForce2 BIOS resulting in XT-PIC timer.
249 as soon as the kernel's real-mode entry point is called.
265 ACPI NVS memory during suspend/hibernation and resume.
270 behave incorrectly in some ways with respect to system
271 suspend and resume to be ignored (use wisely).
277 add_efi_memmap [EFI,X86,EARLY] Include EFI memory map in
287 See Documentation/sound/alsa-configuration.rst
294 align_va_addr= [X86-64]
299 CPU-intensive style benchmark, and it can vary highly in
302 32: only for 32-bit processes
303 64: only for 64-bit processes
304 on: enable for both 32- and 64-bit processes
305 off: disable for both 32- and 64-bit processes
315 Allow execve() of 32-bit applications and setting of the
317 subset of the CPUs support 32-bit EL0. When this
318 parameter is present, the set of CPUs supporting 32-bit
320 and hot-unplug operations may be restricted.
322 See Documentation/arch/arm64/asymmetric-32bit.rst for more
325 amd_iommu= [HW,X86-64]
326 Pass parameters to the AMD IOMMU driver in the system.
328 fullflush - Deprecated, equivalent to iommu.strict=1
329 off - do not initialize any AMD IOMMU found in
331 force_isolation - Force device isolation for all
336 force_enable - Force enable the IOMMU on platforms known
339 pgtbl_v1 - Use v1 page table for DMA-API (Default).
340 pgtbl_v2 - Use v2 page table for DMA-API.
341 irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
342 nohugepages - Limit page-sizes used for v1 page-tables
344 v2_pgsizes_only - Limit page-sizes used for v1 page-tables
348 amd_iommu_dump= [HW,X86-64]
354 amd_iommu_intr= [HW,X86-64]
357 legacy - Use legacy interrupt remapping mode.
358 vapic - Use virtual APIC mode, which allows IOMMU
360 This mode requires kvm-amd.avic=1.
369 In this mode autonomous selection is disabled.
383 selects a performance level in this range and appropriate
389 Disable amd-pstate preferred core.
402 Power management functions (SPARCstation-4/5 + deriv.)
404 Disable APC CPU standby support. SPARCstation-Fox does
405 not play well with APC CPU idle - disable it if you have
412 when initialising the APIC and IO-APIC components.
413 For X86-32, this can also be used to specify an APIC
436 0 -- disable.
437 1 -- enable.
440 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
488 audit= [KNL] Enable the audit sub-system
490 0 | off - kernel audit is disabled and can not be
492 unset - kernel audit is initialized but disabled and
494 1 | on - kernel audit is initialized and partially
496 messages in RAM until it is fully enabled by the
507 0 - Disable the BAU.
508 1 - Enable the BAU.
509 unset - Disable the BAU.
548 See Documentation/block/cmdline-partition.rst
562 See Documentation/admin-guide/bootconfig.rst
567 bttv.pll= See Documentation/admin-guide/media/bttv.rst
576 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
584 [NET] Specifies amount of time (in seconds) that
595 inclusive. See arch/mips/include/asm/pgtable-bits.h
605 - foo isn't auto-mounted if you mount all cgroups in
607 - foo isn't visible as an individually mountable
609 - if foo is an optional feature then the feature is
615 Specifying "pressure" disables per-cgroup pressure
618 cgroup_no_v1= [KNL] Disable cgroup controllers and named hierarchies in v1
622 the blacklisted controllers remain available in cgroup2.
633 nosocket -- Disable socket memory accounting.
634 nokmem -- Disable kernel memory accounting.
635 nobpf -- Disable BPF memory accounting.
640 0 -- check protection applied by kernel (includes
642 1 -- check protection requested by application.
654 numbers X. Note the Linux-specific bits are not necessarily
655 stable over kernel options, but the vendor-specific
657 X can also be a string as appearing in the flags: line
658 in /proc/cpuinfo which does not have the above
660 in /proc/cpuinfo.
665 being used by the kernel or shown in /proc/cpuinfo.
673 device driver but are enabled in hardware at reset or
675 force such clocks to be always-on nor does it reserve
676 those clocks in any way. This parameter is useful for
679 information, see Documentation/driver-api/clk.rst.
681 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
698 [X86-32] pit,hpet,tsc;
704 [SPARC64] tick
705 [X86-64] hpet,tsc
711 architected timer so that code using WFE-based polling
723 no replacement if the same CPU is chosen twice.
725 clocksource-wdtest.holdoff= [KNL]
726 Set the time in seconds that the clocksource
731 cma=nn[MG]@[start[MG][-end[MG]]]
742 Sets the size of kernel per-numa memory area for
744 per-numa CMA altogether. And If this option is not
746 With per-numa CMA enabled, DMA users on node nid will
748 which is located in node nid, if the allocation fails,
759 which is located in node nid, if the allocation fails,
762 cmo_free_hint= [PPC] Format: { yes | no }
764 when they are freed. This is used in CMO environments
773 com20020= [HW,NET] ARCnet - COM20020 chipset
777 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
781 ARCnet - COM90xx chipset (memory-mapped buffers)
790 the console buffer is full. In this case the
795 terminal emulator is active. If no 3270 terminal
796 emulator is used, this parameter has no effect.
810 See Documentation/admin-guide/serial-console.rst for more
825 $ ls -d /sys/bus/serial-base/devices/*:*.*/tty/*
826 /sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0
828 In the above example, the console can be addressed with
831 is ready. The use of an earlycon parameter in addition to
839 Start an early, polled-mode console on the 8250/16550
842 MMIO inter-register address stride is either 8-bit
843 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
845 to be equivalent to 'mmio'. 'options' are specified in
847 the h/w is not re-initialized.
866 By default we print messages on consoles in
874 syscall, or to executing "dmesg -S --raw" or to reading
877 consoleblank= [KNL] The console blank (screen saver) timeout in
898 disable the cpuidle sub-system
904 disable the cpufreq sub-system
908 policy to use. This governor must be registered in the
912 [X86,EARLY] Delay for N microsec between assert and de-assert
914 on every CPU online, such as boot, and resume from suspend.
921 the parameter has no effect.
928 In configurations where kdump may not be reliable,
933 like Hyper-V, PowerPC (fadump) and AMD SEV-SNP.
941 [KNL, X86-64, ARM64, RISCV, LoongArch] Select a region
944 See Documentation/admin-guide/kdump/kdump.rst for further details.
948 in the running system. The syntax of range is
949 start-[end] where start and end are both
951 Documentation/admin-guide/kdump/kdump.rst for an example.
954 [KNL, X86-64, ARM64, RISCV, LoongArch] range could be
962 [KNL, X86-64, ARM64, RISCV, LoongArch] range under 4G.
968 for 32-bit devices won't run out. Kernel would try to allocate
971 --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
972 --> arm64: 128MiB
973 --> riscv: 128MiB
974 --> loongarch: 128MiB
982 [KNL] Disable crypto self-tests
990 csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
993 in case a hanging CPU is detected, and that
994 CPU is pinged again in order to try to resolve
1005 See also Documentation/input/devices/joystick-parport.rst
1010 [KNL,EARLY] Enable printing [hashed] pointers early in the
1018 [KNL] verbose locking self-tests
1021 self-tests.
1023 (no extra messages), setting it to -1 (all bits set)
1024 will print _a_lot_ more information - normally only
1038 random memory corruption problems caused by bugs in
1059 Format: { on, no-mount, off }
1061 no-mount:
1066 get a -EPERM as result when trying to register files
1069 debugfs was not enabled in the kernel at all.
1070 Default value is set in build-time with a kernel configuration.
1077 APIs. In addition, this is the default hugetlb size
1082 Documentation/admin-guide/mm/hugetlbpage.rst.
1086 [KNL] Debugging option to set a timeout in seconds for
1089 drivers) that have opted in will be ignored. A timeout
1096 delayacct [KNL] Enable per-task delay accounting
1109 [HW] Report power status in /proc/i8k
1126 off: No s390 zlib hardware support
1182 entries for DMA-API debugging code. One entry is
1183 required per DMA-API allocation. Use this if the
1184 DMA-API debugging code disables itself because the
1188 With this option the DMA-API debugging driver
1198 kernel data values previously stored in floating point
1208 are enabled. In order to disable RFDS mitigation all
1212 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1223 panels may send no or incorrect EDID data sets.
1225 in the /lib/firmware directory that are used instead.
1230 data set with no connector name will be used for
1237 Control how the dt_cpu_ftrs device-tree binding is
1247 what data is available or for reverse-engineering.
1252 Documentation/admin-guide/dynamic-debug-howto.rst
1256 Enable debug messages in early_ioremap support. This
1262 When used with no options, the early console is
1263 determined by stdout-path property in device tree's
1268 Start an early, polled-mode console on a Cadence
1279 Start an early, polled-mode console on the 8250/16550
1281 MMIO inter-register address stride is either 8-bit
1282 (mmio) or 32-bit (mmio32 or mmio32be).
1285 in the same format described for "console=ttyS<n>"; if
1292 Start an early, polled-mode console on a pl011 serial
1296 the driver will use only 32-bit accessors to read/write
1305 Start an early, polled-mode console on a meson serial
1311 Start an early, polled-mode console on an msm serial
1317 Start an early, polled-mode console on an msm serial
1323 Start an early, polled-mode console on a serial port
1329 Start an early, polled-mode console on a serial port
1335 Use RISC-V SBI (Supervisor Binary Interface) for early
1353 Start an early, polled-mode console on a lantiq serial
1367 Start an early, polled-mode, output-only console on the
1372 Start an early, polled-mode console on the
1378 Start an early, polled-mode console on a Qualcomm
1386 coherent non-x86 systems that use system memory for
1423 You can find the port for a given device in
1433 The xen option can only be used in Xen domains.
1460 PCI bridges while in the EFI boot stub.
1461 nochunk: disable reading files in "chunks" in the EFI
1473 on all PCI bridges while in the EFI boot stub
1485 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1494 This is designed to be used in conjunction with
1497 This parameter works in place of the kgdboc parameter
1499 very early in the boot process. For early debugging
1502 elanfreq= [X86-32]
1503 See comment before function elanfreq_setup() in
1510 See Documentation/admin-guide/kdump/kdump.rst for details.
1520 (in particular on some ATI chipsets).
1526 0 -- permissive (log only, no denials).
1527 1 -- enforcing (deny and log).
1560 See also Documentation/fault-injection/.
1564 See Documentation/admin-guide/sysctl/net.rst for
1568 See Documentation/admin-guide/blockdev/floppy.rst.
1570 forcepae [X86-32]
1577 fred= [X86-64]
1585 as early as possible in order to facilitate early
1608 If no parameter is passed, ftrace will dump global
1628 ftrace_filter=[function-list]
1630 tracer at boot up. function-list is a comma-separated
1632 time by the set_ftrace_filter file in the debugfs
1635 ftrace_notrace=[function-list]
1636 [FTRACE] Do not trace the functions specified in
1637 function-list. This list can be changed at run time
1638 by the set_ftrace_notrace file in the debugfs
1641 ftrace_graph_filter=[function-list]
1644 function-list is a comma-separated list of functions
1646 set_graph_function file in the debugfs tracing directory.
1648 ftrace_graph_notrace=[function-list]
1649 [FTRACE] Do not trace from the functions specified in
1650 function-list. This list is a comma-separated list of
1652 set_graph_notrace file in the debugfs tracing directory.
1658 in the tracefs tracing directory. default: 0 (no limit)
1667 suspend/resume & runtime PM (consumers first, then
1670 off -- Don't create device links from firmware info.
1671 permissive -- Create device links from firmware info
1674 on -- Create device links from firmware info and use it
1675 to enforce probe and suspend/resume ordering.
1676 rpm -- Like "on", but also use to order runtime PM.
1689 strict -- Default. Continue waiting on consumers to
1691 timeout -- Give up waiting on consumers and call
1701 See also Documentation/input/devices/joystick-parport.rst
1705 gart_fix_e820= [X86-64,EARLY] disable the fix e820 for K8 GART
1715 previously stored in vector registers.
1717 This issue is mitigated by default in updated microcode.
1723 microcode mitigation. No effect if the microcode
1724 mitigation is present. Known to cause crashes in
1729 gcov_persist= [GCOV] When non-zero (default), profiling data for
1739 gpio-mockup.gpio_mockup_ranges
1742 gpio-mockup.gpio_mockup_named_lines
1774 against bounds-checking flaws in the kernel's
1780 [KNL] Should the hard-lockup detector generate
1786 for 64-bit NUMA, off otherwise.
1794 corresponding firmware-first mode error processing
1801 no Disable hibernation and resume.
1804 during restoration read-only).
1818 size of <nn>. This works even on boxes that have no
1836 has been explicitly set, resulting in the calling
1841 hpet= [X86-32,HPET] option to control HPET usage
1858 number of pages to allocate per-node can be specified.
1859 See also Documentation/admin-guide/mm/hugetlbpage.rst.
1864 [HW] The size of the HugeTLB pages. This is used in
1870 Documentation/admin-guide/mm/hugetlbpage.rst.
1881 boot-time allocation of gigantic hugepages is skipped.
1909 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1915 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1931 Set device-properties for ACPI-enumerated I2C-attached
1932 touchscreen, to e.g. fix coordinates of upside-down
1940 Omit "=<val>" entirely Set a boolean device-property
1941 Unsigned number Set a u32 device-property
1942 Anything else Set a string device-property
1945 i2c_touchscreen_props=GDIX1001:touchscreen-inverted-x:
1946 touchscreen-inverted-y
1948 i2c_touchscreen_props=MSSL1680:touchscreen-size-x=1920:
1949 touchscreen-size-y=1080:touchscreen-inverted-y:
1950 firmware-name=gsl1680-vendor-model.fw:silead,home-button
1955 (disabled by default, and as a pre-condition
1957 i8042.direct [HW] Put keyboard port into non-translated mode
1971 suspend-to-ram transitions, only during s2r
1995 -1 -- never invert brightness
1996 0 -- machine default
1997 1 -- force brightness inversion
1999 ia32_emulation= [X86-64]
2001 When true, allows loading 32-bit programs and executing 32-bit
2016 In such case C2/C3 won't be used again.
2017 idle=nomwait: Disable mwait for CPU C-states
2045 legacy only accept legacy-NaN binaries, if supported
2047 2008 only accept 2008-NaN binaries, if supported
2055 encodings, so if no FPU hardware is present or it has
2058 'relaxed' straps the emulator for both legacy-NaN and
2059 2008-NaN, whereas 'strict' enables legacy-NaN only on
2068 Ignore loglevel setting - this will print /all/
2100 in crypto/hash_info.h.
2135 Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" |
2136 "ima-sigv2" }
2137 Default: "ima-ng"
2169 initcall_blacklist= [KNL] Do not execute a comma-separated list of
2170 initcall functions. Useful for debugging built-in
2188 load the initrd. If an initrd is compiled in or
2189 specified in the bootparams, it takes priority over this
2206 override in debugfs after boot.
2215 0 -- basic integrity auditing messages. (Default)
2216 1 -- additional integrity auditing messages.
2226 bypassed by not enabling DMAR with this option. In
2244 could harm performance of some high-throughput
2253 1 to 9 specify maximum depth of C-state.
2262 algorithms for p-state selection. There are two
2263 P-state selection algorithms provided by
2264 intel_pstate in the active mode: powersave and
2266 on whether or not the hardware managed P-states
2267 (HWP) feature has been enabled in the processor
2273 used along with the hardware-managed P-states (HWP)
2277 in favor of acpi-cpufreq. Forcing the intel_pstate driver
2278 instead of acpi-cpufreq may disable platform features, such
2280 P-States information being indicated to OSPM and therefore
2283 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
2296 Allow per-logical-CPU P-State performance control limits using
2299 intremap= [X86-64,Intel-IOMMU,EARLY]
2304 BIOS x2APIC opt-out request will be ignored
2330 0 - Try to allocate a 32-bit DMA address first, before
2332 1 - Allocate directly from the full usable range,
2334 greater than 32-bit addressing.
2338 0 - Lazy mode.
2344 1 - Strict mode.
2347 unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
2349 legacy driver-specific options takes precedence.
2354 0 - Use IOMMU translation for DMA.
2355 1 - Bypass the IOMMU for DMA.
2356 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2358 io7= [HW] IO7 for Marvel-based Alpha systems
2359 See comment before marvel_specify_io7 in
2370 No delay
2373 See Documentation/admin-guide/nfs/nfsroot.rst.
2380 Determine whether IPE starts in permissive (0) or
2405 to let secondary kernels in charge of setting up
2409 Enables support for pseudo-NMIs in the kernel. This
2428 [Deprecated - use cpusets instead]
2429 Format: [flag-list,]<cpu-list>
2432 specified in the flag list (default: domain):
2435 Disable the tick when a single task runs.
2437 A residual 1Hz tick is offloaded to workqueues, which you
2455 move in and out of an isolated set anytime.
2460 "number of CPUs in system - 1".
2479 CPUs then this parameter has no effect on the
2483 housekeeping CPUs has no influence on those
2486 The format of <cpu-list> is described above.
2490 ivrs_ioapic [HW,X86-64]
2491 Provide an override to the IOAPIC-ID<->DEVICE-ID
2492 mapping provided in the IVRS ACPI table.
2495 For example, to map IOAPIC-ID decimal 10 to
2501 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2504 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2508 ivrs_hpet [HW,X86-64]
2509 Provide an override to the HPET-ID<->DEVICE-ID
2510 mapping provided in the IVRS ACPI table.
2513 For example, to map HPET-ID decimal 10 to
2519 * To map HPET-ID decimal 0 to PCI device 00:14.0
2522 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2526 ivrs_acpihid [HW,X86-64]
2527 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2528 mapping provided in the IVRS ACPI table.
2531 For example, to map UART-HID:UID AMD0020:0 to
2537 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2540 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2555 useful for debugging when something happens in the window
2564 the kernel for non-movable allocations. The requested
2565 amount is spread evenly throughout all nodes in the
2567 movable memory in its own zone, ZONE_MOVABLE. In the
2574 subsystem. Note that allocations like PTEs-from-HighMem
2578 It is possible to specify the exact amount of memory in
2580 memory in the form of "nn%", or "mirror". If "mirror"
2582 for non-movable allocations and remaining memory is used
2590 optional and is the number seconds in between
2591 each poll cycle to the debug port in case you need
2593 gdb or control-c on the dbgp connection. When
2594 not using this parameter you use sysrq-g to break into
2599 or a supported polling keyboard driver (non-usb).
2609 characters and can work in polling mode, you can use
2626 Configure the RouterBoard 532 series on-chip
2629 kmemleak= [KNL,EARLY] Boot-time kmemleak enable/disable
2635 kprobe_event=[probe-list]
2637 The probe-list is a semicolon delimited list of probe
2667 execution by eliminating the write-protection faults
2678 disabled, all huge pages in a memslot will be eagerly
2689 If enabled, KVM will enable virtualization in hardware
2694 virtualization on-demand when creating and destroying
2702 is that doing so may interfere with using out-of-tree
2729 back to huge pages. If the value is a non-zero N, KVM will
2734 kvm-amd.nested= [KVM,AMD] Control nested virtualization feature in
2737 kvm-amd.npt= [KVM,AMD] Control KVM's use of Nested Page Tables,
2738 a.k.a. Two-Dimensional Page Tables. Default is 1
2742 kvm-arm.mode=
2748 nvhe: Standard nVHE-based mode, without support for
2751 protected: nVHE-based mode with support for guests whose
2754 nested: VHE-based mode with support for nested
2763 kvm-arm.vgic_v3_group0_trap=
2764 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-0
2767 kvm-arm.vgic_v3_group1_trap=
2768 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-1
2771 kvm-arm.vgic_v3_common_trap=
2775 kvm-arm.vgic_v4_enable=
2779 kvm-arm.wfe_trap_policy=
2788 kvm-arm.wfi_trap_policy=
2805 kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables,
2806 a.k.a. Two-Dimensional Page Tables. Default is 1
2810 kvm-intel.emulate_invalid_guest_state=
2812 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2818 kvm-intel.flexpriority=
2823 kvm-intel.nested=
2824 [KVM,Intel] Control nested virtualization feature in
2827 kvm-intel.unrestricted_guest=
2833 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2834 CVE-2018-3620.
2843 Default is cond (do L1 cache flush in specific instances)
2845 kvm-intel.vpid= [KVM,Intel] Control KVM's use of Virtual Processor
2857 In vulnerable processors, the speculatively
2858 forwarded data can be used in a cache side channel
2865 on - enable the interface for the mitigation
2876 enables all mitigations in the
2882 when the first VM is started in a
2900 when the first VM is started in a
2912 when the first VM is started in a
2918 warn when a VM is started in a potentially
2930 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
2936 lapic [X86-32,APIC,EARLY] Enable the local APIC even if BIOS
2940 value for LAPIC timer one-shot implementation. Default
2941 back to the programmable timer unit in the LAPIC.
2945 in C2 power state.
2959 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
2963 libata.force= [LIBATA] Force configurations. The format is a comma-
2975 first fan-out link behind PMP device. It does not
2980 as there is no ambiguity, shortcut notation is allowed.
2989 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
2996 * rstonce: only attempt one reset during hot-unplug
2999 * [no]dbdelay: Enable or disable the extra 200ms delay
3003 * [no]ncq: Turn on or off NCQ.
3005 * [no]ncqtrim: Enable or disable queued DSM TRIM.
3007 * [no]ncqati: Enable or disable NCQ trim on ATI chipset.
3009 * [no]trim: Enable or disable (unqueued) TRIM.
3015 * [no]dma: Turn on or off DMA transfers.
3022 * [no]dmalog: Enable or disable the use of the
3025 * [no]iddevlog: Enable or disable access to the
3028 * [no]logdir: Enable or disable access to the general
3039 * [no]lpm: Enable or disable link power management.
3041 * [no]setxfer: Indicate if transfer speed mode setting
3044 * [no]fua: Disable or enable FUA (Force Unit Access)
3078 Set the time limit in jiffies for a lock
3080 will result in a splat once they do complete.
3091 Specify the number of self-propagating call_rcu()
3094 in progress at any given time. Defaults to 0,
3098 Specify the duration in milliseconds for the
3099 occasional long-duration lock hold time. Defaults
3110 Set the number of locking read-acquisition kthreads.
3115 Set the number of locking write-acquisition kthreads.
3118 Set time (s) after boot for CPU-hotplug testing.
3121 Set time (s) between CPU-hotplug operations, or
3122 zero to disable CPU-hotplug testing.
3125 Do periodic testing of real-time lock priority
3130 non-real-time spinlocks, due to their disabling
3131 of preemption. Note that non-realtime mutexes
3144 Set task-shuffle interval (jiffies). Shuffling
3145 tasks allows some CPUs to go into dyntick-idle
3150 is useful for hands-off automated testing.
3169 Run the write-side locktorture kthreads at
3170 sched_set_fifo() real-time priority.
3188 7 (KERN_DEBUG) debug-level messages
3191 Sets the size of the printk ring buffer, in bytes.
3200 logo.nologo [FB] Disables display of the built-in Linux logo.
3209 specified in addition to the ports) causes
3218 an IEEE 1284-compliant printer is attached; if
3224 time-consuming boot-time autodetection (up to 250 ms per
3231 will cause delays in the kernel to be wrong, leading to
3233 unlikely, in the extreme case this might damage your
3244 Example: machtype=lemote-yeeloong-2f-7inch
3256 (loop.max_loop) unconditionally pre-created at init time. The default
3259 devices can be requested on-demand with the
3260 /dev/loop-control interface.
3262 mce [X86-32] Machine Check Exception
3264 mce=option [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
3267 See Documentation/admin-guide/md.rst.
3274 Control mitigation for the Micro-architectural Data
3281 In vulnerable processors, the speculatively
3282 forwarded data can be used in a cache side channel
3289 full - Enable MDS mitigation on vulnerable CPUs
3290 full,nosmt - Enable MDS mitigation and disable
3292 off - Unconditionally disable MDS mitigation
3294 On TAA-affected machines, mds=off can be prevented by
3296 mitigated with the same mechanism so in order to disable
3303 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3309 of memory Amount of memory to be used in cases
3318 [ARC,MICROBLAZE] - the limit applies only to low memory,
3321 [ARM64] - only limits memory covered by the linear
3330 in above case 3, memory may need be hot added after boot
3334 [ARM,MIPS,EARLY] - override the memory layout
3341 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3348 per-device physically contiguous DMA buffers.
3356 See Documentation/admin-guide/mm/memory-hotplug.rst.
3381 Example: Exclude memory from 0x18690000-0x1869ffff
3395 memmap=<size>%<offset>-<oldtype>+<newtype>
3397 from <oldtype> to <newtype>. If "-<oldtype>" is left
3406 memory when doing things like suspend/resume.
3412 repeatable BIOS-originated corruption always
3417 By default it checks for corruption in the low
3420 corruption in more or less memory.
3439 allocations in some configurations (e.g. small
3441 The state of the flag can be read in
3456 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3462 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
3465 mem_sleep_default= [SUSPEND] Default system suspend mode:
3466 s2idle - Suspend-To-Idle
3467 shallow - Power-On Suspend or equivalent (if supported)
3468 deep - Suspend-To-RAM or equivalent (if supported)
3469 See Documentation/admin-guide/pm/sleep-states.rst.
3471 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
3487 0 - The attached screen is the 3.5" TFT
3488 1 - The attached screen is the 7" TFT
3489 2 - The VGA Shield is attached (1024x768)
3493 b - Enable backlight. The TFT backlight pin will be
3497 c - Enable the s3c camera interface.
3498 t - Reserved for enabling touchscreen support. The
3499 touchscreen support is not enabled in the mainstream
3501 in the "bleeding edge" mini2440 support kernel at
3502 https://repo.or.cz/w/linux-2.6/mini2440.git
3507 arch-independent options, each of which is an
3508 aggregation of existing arch-specific options.
3537 ssbd=force-off [ARM64]
3550 have other ways of avoiding SMT-based attacks.
3577 operation. Exposed data could originate or end in
3585 full - Enable mitigation on vulnerable CPUs
3587 full,nosmt - Enable mitigation and disable SMT on
3590 off - Unconditionally disable mitigation
3595 mitigated with the same mechanism so in order to
3603 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3606 If no <bool> value is specified or if the value
3633 module_blacklist= [KNL] Do not load a comma-separated list of
3640 touchpads working in absolute mode only).
3658 movable_node [KNL,EARLY] Boot-time switch to make hotplugable memory
3665 Format: <name>,<region-number>,<size>,<offset>
3668 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3707 something different and driver-specific.
3708 This usage is only documented in each driver source
3712 [NET] Specifies amount of time (in seconds) that
3747 [NFS] enable 64-bit inode numbers.
3748 If zero, the NFS client will fake up a 32-bit inode
3750 of returning the full 64-bit number.
3751 The default is to return 64-bit inode numbers.
3761 callbacks the client will process in parallel for
3769 Note that there is little point in setting this
3777 'sec=sys' security flavour. In effect it is
3786 [NFS4] Specify an additional fixed unique ident-
3795 no guarantees that the file will remain unchanged
3805 information in exchange_id requests.
3806 If zero, no implementation identification information
3817 driver. A non-zero value sets the minimum interval
3818 in seconds between layoutstats transmissions.
3822 server-to-server copies for which this server is
3834 server-to-server copy, knfsd temporarily mounts
3835 the source server. It caches the mount in case
3841 See Documentation/admin-guide/nfs/nfsroot.rst.
3843 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3844 See Documentation/admin-guide/nfs/nfsroot.rst.
3847 See Documentation/admin-guide/nfs/nfsroot.rst.
3850 Dump stacks even of idle CPUs in response to an
3851 NMI stack-backtrace request.
3860 0 - turn hardlockup detector in nmi_watchdog off
3861 1 - turn hardlockup detector in nmi_watchdog on
3862 rNNN - configure the watchdog with raw perf event 0xNNN
3875 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
3879 no4lvl [RISCV,EARLY] Disable 4-level and 5-level paging modes.
3880 Forces kernel to use 3-level paging instead.
3882 no5lvl [X86-64,RISCV,EARLY] Disable 5-level paging mode. Forces
3883 kernel to use 4-level paging instead.
3888 IOAPICs that may be present in the system.
3895 [HW] Never suspend the console
3896 Disable suspending of consoles during suspend and
3900 debugging driver suspend/resume hooks). This may
3916 no_entry_flush [PPC,EARLY] Don't flush the L1-D cache when entering the kernel.
3918 noexec32 [X86-64]
3919 This affects only 32-bit executables.
3920 noexec32=on: enable non-executable mappings (default)
3922 noexec32=off: disable non-executable mappings
3933 nofxsr [BUGS=X86-32] Disables x86 floating point extended
3935 legacy floating-point registers on task switch.
3945 difficult since unequal pointers can no longer be
3946 compared. However, if this command-line option is
3955 busy wait in do_idle() and not use the arch_cpu_idle()
3973 In kernels built with CONFIG_NO_HZ_FULL=y, set
3974 the specified list of CPUs whose tick will be stopped
3977 in this list will have their RCU callbacks offloaded,
3978 just as if they had also been called out in the
3987 nointremap [X86-64,Intel-IOMMU,EARLY] Do not enable interrupt
3989 [Deprecated - use intremap=off]
3995 noirqdebug [X86-32] Disables the code which attempts to detect and
4005 no-kvmapf [X86,KVM,EARLY] Disable paravirtualized asynchronous page
4008 no-kvmclock [X86,KVM,EARLY] Disable paravirtualized KVM clock driver
4010 nolapic [X86-32,APIC,EARLY] Do not enable or use the local APIC.
4012 nolapic_timer [X86-32,APIC,EARLY] Do not use the local APIC timer.
4014 nomce [X86-32] Disable Machine Check Exception
4016 nomfgpt [X86-32] Disable Multi-Function General Purpose
4022 not load if they could possibly displace the pre-
4025 perform display-mode changes or accelerated rendering.
4038 nopcid [X86-64,EARLY] Disable the PCID cpu feature.
4041 in some Intel CPUs.
4043 nopti [X86-64,EARLY]
4048 as generic guest with no PV drivers. Currently support
4059 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
4065 no-scroll [VGA] Disables scrollback.
4066 This is required for the Braillex ib80-piezo Braille
4069 nosgx [X86-64,SGX,EARLY] Disables Intel SGX kernel support.
4089 nosoftlockup [KNL] Disable the soft-lockup detector.
4095 nospectre_bhb [ARM64,EARLY] Disable all mitigations for Spectre-BHB (branch
4101 possible in the system.
4108 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,LOONGARCH,EARLY]
4118 [PPC,EARLY] Don't flush the L1-D cache after accessing user data.
4124 without any limit and this data is stored in memory,
4127 data will be no longer available. This parameter
4131 no-vmw-sched-clock
4136 soft-lockup and NMI watchdog (hard-lockup).
4140 nox2apic [X86-64,APIC,EARLY] Do not enable x2APIC mode.
4143 LEGACY_XAPIC_DISABLED bit set in the
4148 enabling legacy floating-point and sse state.
4150 noxsaveopt [X86] Disables xsaveopt used in saving x86 extended
4157 noxsaves [X86] Disables xsaves and xrstors used in saving and
4158 restoring x86 extended register state in compacted
4161 in standard form of xsave area. By using this
4168 number of already plugged CPU during bootup, later in
4170 n. So during boot up some boot time memory for per-cpu
4171 variables need be pre-allocated for later physical cpu
4202 See Documentation/admin-guide/sysctl/vm.rst for details.
4205 See Documentation/core-api/debugging-via-ohci1394.rst for more
4220 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4224 boundary - index of last SLC block on Flex-OneNAND.
4226 lock - Configure if Flex-OneNAND boundary should be locked.
4245 page_owner= [KNL,EARLY] Boot-time page_owner enabling option.
4247 each page is disabled in default. With this switch,
4251 page_poison= [KNL,EARLY] Boot-time parameter changing the state of
4270 Bitmask for conditionally calling panic() in add_taint()
4274 called with any of the flags in this set.
4279 See Documentation/admin-guide/tainted-kernels.rst for
4293 bit 5: print all printk messages in buffer
4294 bit 6: print all CPUs backtrace (if available in the arch)
4295 bit 7: print only tasks in uninterruptible (blocked) state
4297 so there are risks of losing older messages in the log.
4318 Parallel ports are assigned in the order they
4323 Configure VIA parallel port to operate in
4325 computer where firmware has no options for setting
4332 Set to non-zero to probe primary and secondary ISA
4333 port ranges on PCI systems where no PCI PATA device
4338 Set to non-zero if a chip is present that snoops speed
4386 Set to non-zero to probe tertiary and further ISA
4396 corresponding bits in the mask to 1. Bit 0 is for
4397 the first port in the list above (0x1f0), and so on.
4402 Set to non-zero to probe QDI controllers. By default
4407 Set to non-zero to probe Winbond controllers. Use
4431 specified in one of the following formats:
4449 devices in the system.
4454 bios [X86-32] force use of PCI BIOS, don't access
4456 has a non-standard PCI host bridge.
4457 nobios [X86-32] disallow use of PCI BIOS, only direct
4462 Mechanism 1 (config address in IO port 0xCF8,
4463 data in IO port 0xCFC, both 32-bit).
4465 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4466 the function, IO port 0xCFA, also 8-bit, sets
4468 through ports 0xC000-0xCFFF).
4475 root domains (aka PCI segments, in ACPI-speak).
4483 disable the use of MSI interrupts system-wide.
4488 primary IO-APIC for bridges that cannot disable
4495 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4519 F0000h-100000h range.
4524 assign-busses [X86] Always assign all PCI bus
4528 in the BIOS $PIR table. This is needed on
4531 notebooks. This will have no effect if ACPI
4543 for BIOS defects in host bridge _CRS methods.
4545 <linux-pci@vger.kernel.org>.
4549 a bug to <linux-pci@vger.kernel.org>.
4551 This is normally done in pci_enable_device(),
4561 bfsort Sort PCI devices into breadth-first order.
4564 nobfsort Don't sort PCI devices into breadth-first order.
4566 tuning and use the BIOS-configured MPS defaults.
4572 value (no larger than the MPS that the device
4576 configuration allows peer-to-peer DMA between
4579 that hot-added devices will work.
4594 A PCI-PCI bridge can be specified if resource
4600 for 4096-byte alignment.
4602 end-to-end CRC checking). Only effective if
4633 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4645 Specify one or more PCI devices (in the format
4652 may put more devices in an IOMMU group.
4656 Specify one or more PCI devices (in the format
4660 unchanged based on what is specified in
4664 bit-0 : ACS Source Validation
4665 bit-1 : ACS Translation Blocking
4666 bit-2 : ACS P2P Request Redirect
4667 bit-3 : ACS P2P Completion Redirect
4668 bit-4 : ACS Upstream Forwarding
4669 bit-5 : ACS P2P Egress Control
4670 bit-6 : ACS Direct Translated P2P
4680 Validation unchanged from whatever power-up
4684 and may put more devices in an IOMMU group.
4692 system-wide.
4706 dpc-native Use native PCIe service for DPC only. May
4723 Keep all power-domains already enabled by bootloader on,
4724 even if no driver has claimed them. This is useful
4737 See comments in mm/percpu.c for details on each
4741 pirq= [SMP,APIC] Manual mp-table setup
4742 See Documentation/arch/x86/i386/IO-APIC.rst.
4746 See also Documentation/admin-guide/parport.rst.
4753 This option takes over the PMU facility, so it is no
4760 pm_debug_messages [SUSPEND,KNL]
4761 Enable suspend/resume debug messages during boot up.
4765 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4774 { on | off | curr | res | no-curr | no-res }
4783 Ranges are in pairs (I/O port base and size).
4788 Ranges are in pairs (memory base and size).
4819 none - Limited to cond_resched() calls
4820 voluntary - Limited to cond_resched() and might_sleep() calls
4821 full - Any section that isn't explicitly preempt disabled
4825 lazy - Scheduler controlled. Similar to full but instead
4827 one HZ tick time to yield itself before the
4831 print-fatal-signals=
4837 coredump - etc.
4840 you might want to try "ulimit -i unlimited".
4852 or lockdep-detected issues (only if lock debug is on).
4855 in order to provide more debug information.
4861 on - unlimited logging to /dev/kmsg from userspace
4862 off - logging to /dev/kmsg disabled
4863 ratelimit - ratelimit the logging
4874 - 'always': traditional behavior always allows mem overrides.
4875 - 'ptrace': only allow mem overrides for active ptracers.
4876 - 'never': never allow mem overrides.
4880 Limit processor to maximum C-state
4884 Ignore the _CST method to determine C-states,
4891 Param: "schedule" - profile schedule points.
4892 Param: "kvm" - profile VM exits.
4893 Param: <number> - step/bucket size as a power of 2 for
4911 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
4917 [HW,MOUSE] Set desired mouse resolution, in dpi.
4924 pti= [X86-64] Control Page Table Isolation of user and
4929 on - unconditionally enable
4930 off - unconditionally disable
4931 auto - kernel detects whether your CPU model is
4937 [KNL] Number of legacy pty's. Overwrites compiled-in
4949 See Documentation/admin-guide/md.rst.
4951 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
4952 See Documentation/admin-guide/blockdev/ramdisk.rst.
4971 cross-syscall address exposures. This is only
4977 ras=option[,option,...] [KNL] RAS-specific options
4983 rcu_nocbs[=cpu-list]
4987 In kernels built with CONFIG_RCU_NOCB_CPU=y,
4988 enable the no-callback CPU mode, which prevents
4989 such CPUs' callbacks from being invoked in
4993 "p" for RCU-preempt, "s" for RCU-sched, and "g"
4997 and real-time workloads. It can also improve
5001 list of CPUs is set to no-callback mode from boot.
5004 arguments are omitted, no CPU will be set to
5005 no-callback mode from boot but the mode may be
5016 This improves the real-time response for the
5024 process in one batch.
5027 Do only a one-line RCU CPU stall warning when
5028 there is an ongoing too-long CSD-lock wait.
5034 If triggered before the RCU grace-period machinery
5044 RCU grace-period cleanup.
5048 RCU grace-period initialization.
5052 RCU grace-period pre-initialization, that is,
5053 the propagation of recent CPU-hotplug changes up
5057 Set delay from grace-period initialization to
5068 Set required age in jiffies for a
5070 soliciting quiescent-state help from
5076 This calculated value may be viewed in
5082 Set the SCHED_FIFO priority of the RCU per-CPU
5085 and for the RCU grace-period kthreads (rcu_bh,
5087 set, valid values are 1-99 and the default is 1
5088 (the least-favored priority). Otherwise, when
5089 RCU_BOOST is not set, valid values are 0-99 and
5090 the default is zero (non-realtime operation).
5095 On callback-offloaded (rcu_nocbs) CPUs,
5098 use of the ->nocb_bypass list. However, in the
5099 common non-flooded case, RCU queues directly to
5100 the main ->cblist in order to avoid the extra
5101 overhead of the ->nocb_bypass list and its lock.
5103 a single jiffy, RCU pre-queues the callbacks into
5104 the ->nocb_bypass queue. The definition of "too
5108 On callback-offloaded (rcu_nocbs) CPUs, avoid
5110 reached the specified age in milliseconds.
5121 batch limiting is re-enabled.
5125 RCU's force-quiescent-state scan will aggressively
5133 Set the page-cache refill delay (in milliseconds)
5134 in response to low-memory conditions. The range
5135 of permitted values is in the range 0:100000.
5138 Set the shift-right count to use to compute
5139 the callback-invocation batch limit bl from
5143 callbacks, the softirq handler will exit in
5146 Please note that this callback-invocation batch
5147 limit applies only to non-offloaded callback
5149 invoked in the context of an rcuoc kthread, which
5156 cache-to-cache transfer latencies.
5162 and for NUMA systems with large remote-access
5171 whole algorithm to behave better in low memory
5175 Set the number of NOCB callback kthreads in
5178 the wakeup overhead on the global grace-period
5180 each group's NOCB grace-period kthread.
5183 Cause the grace-period kthread to get an extra
5185 it should at force-quiescent-state time.
5193 every 32 callbacks in order to limit the pain
5197 In CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels,
5198 this specifies an rcu_read_unlock()-time delay
5199 in microseconds. This defaults to zero.
5202 of RCU-protected pointers after the relevant
5212 per-CPU rcuc kthreads. Defaults to a non-zero
5241 grace-period primitives such as call_rcu().
5252 grace-period primitives.
5255 Set test-start holdoff period. The purpose of
5257 test until boot completes in order to avoid
5261 In kernels built with CONFIG_RCU_LAZY=y, test
5273 Test the double-argument variant of kfree_rcu().
5275 rcuscale.kfree_rcu_test_single, both the single-
5276 and double-argument variants are tested.
5279 Test the single-argument variant of kfree_rcu().
5281 rcuscale.kfree_rcu_test_double, both the single-
5282 and double-argument variants are tested.
5288 Number of allocations and frees done in an iteration.
5295 Set the minimum test run time in seconds. This
5296 does not affect the data-collection interval,
5301 Set number of RCU readers. The value -1 selects
5303 "n" less than -1 selects N-n+1, where N is again
5304 the number of CPUs. For example, -2 selects N
5305 (the number of CPUs), -3 selects N+1, and so on.
5306 A value of "n" less than or equal to -N selects
5319 complete. This is useful for hands-off automated
5326 Write-side holdoff between grace periods,
5327 in microseconds. The default of zero says
5328 no holdoff.
5331 Additional write-side holdoff between grace
5332 periods, but in jiffies. The default of zero
5333 says no holdoff.
5337 in microseconds.
5341 in microseconds.
5345 in seconds.
5349 for RCU grace-period forward-progress testing
5356 Specify the fraction of a CPU-stall-warning
5357 period to do tight-loop forward-progress testing.
5361 forward-progress tests.
5365 need_resched() during tight-loop forward-progress
5369 Use conditional/asynchronous update-side
5373 Use expedited update-side primitives, if available.
5376 Use normal (non-expedited) asynchronous
5377 update-side primitives, if available.
5380 Use normal (non-expedited) synchronous
5381 update-side primitives, if available. If all
5385 they are all non-zero.
5393 Leak an RCU-protected pointer out of the reader.
5394 This can of course result in splats, and is
5404 stress RCU, they don't participate in the actual
5408 Set number of RCU callback-offload togglers.
5412 Set the delay in milliseconds between successive
5413 callback-offload toggling attempts.
5416 Set number of RCU readers. The value -1 selects
5417 N-1, where N is the number of CPUs. A value
5418 "n" less than -1 selects N-n-2, where N is again
5419 the number of CPUs. For example, -2 selects N
5420 (the number of CPUs), -3 selects N+1, and so on.
5423 Enable debug-object double-call_rcu() testing.
5426 Set time (s) after boot for CPU-hotplug testing.
5429 Set time (jiffies) between CPU-hotplug operations,
5430 or zero to disable CPU-hotplug testing.
5433 The number of times in a given read-then-exit
5434 episode that a set of read-then-exit kthreads
5438 The delay, in seconds, between successive
5439 read-then-exit testing episodes.
5444 are entered from low-order bit up, and are
5445 exited in the opposite order. For SRCU, the
5446 0x1 bit is normal readers, 0x2 NMI-safe readers,
5447 and 0x4 light-weight readers.
5450 Set task-shuffle interval (s). Shuffling tasks
5451 allows some CPUs to go into dyntick-idle mode
5456 is useful for hands-off automated testing.
5464 in warnings from preemptible RCU in addition to
5465 any other stall-related activity. Note that
5466 in kernels built with CONFIG_PREEMPTION=n and
5471 in scheduling-while-atomic splats.
5473 Use of this module parameter results in splats.
5481 on the first stall in the set.
5486 in four stall sequences.
5490 grace-period kthread to test RCU CPU stall
5505 Test RCU priority boosting? 0=no, 1=maybe, 2=yes.
5516 Test RCU's dyntick-idle handling. See also the
5531 warnings in the RCU_CPU_STALL_NOTIFIER Kconfig
5546 The value is in seconds and the maximum allowed
5551 messages. The value is in milliseconds
5554 adjusted to an arch timer tick resolution.
5571 Use expedited grace-period primitives, for
5575 real-time latency, and degrade energy efficiency.
5576 No effect on CONFIG_TINY_RCU kernels.
5579 Use only normal grace-period primitives,
5582 real-time latency, CPU utilization, and
5584 increased grace-period latency. This parameter
5585 overrides rcupdate.rcu_expedited. No effect on
5591 only normal grace-period primitives. No effect
5597 post-boot attempt at an expedited RCU grace
5598 period to instead use normal non-expedited
5599 grace-period processing.
5607 set to the default value of -1.
5610 Set the minimum number of callback-queuing-time
5611 lock-contention events per jiffy required to
5612 cause the RCU Tasks flavors to switch to per-CPU
5615 the default value of -1.
5620 of -1 allows this to be automatically (and
5622 for use in testing.
5625 Set time in jiffies during which RCU tasks will
5628 number avoids disturbing real-time workloads,
5633 cancel laziness on that CPU. Use -1 to disable
5639 Set initial timeout in jiffies for RCU task stall
5643 only printed prior to the stall-warning message
5646 seconds. A change in value does not take effect
5661 Set timeout in jiffies for RCU task stall
5664 A change in value does not take effect until
5668 Set timeout in milliseconds RCU Tasks asynchronous
5675 Set timeout in milliseconds RCU Tasks
5691 force - Override the decision by the kernel to hide the
5694 support, specifically around the suspend/resume
5719 Set test-start holdoff period. The purpose of
5721 test until boot completes in order to avoid
5734 but the default has already reduced the per-pass
5739 Set number of readers. The default value of -1
5748 Set the read-side critical-section duration,
5749 measured in microseconds.
5752 Specify the read-protection implementation to test.
5772 that are unused, due no driver claiming them. This may
5778 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
5808 reservetop= [X86-32,EARLY]
5817 Specify the partition device for software suspend
5824 in <PAGE_SIZE> units (needed only for swap files).
5825 See Documentation/power/swsusp-and-swap-files.rst
5827 resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
5841 AMD-based UNRET and IBPB mitigations alone do not stop
5843 sibling threads. For that reason, STIBP is used on pro-
5847 off - no mitigation
5848 auto - automatically select a migitation
5849 auto,nosmt - automatically select a mitigation,
5853 ibpb - On AMD, mitigate short speculation
5858 ibpb,nosmt - Like "ibpb" above but will disable SMT
5862 unret - Force enable untrained return thunks,
5863 only effective on AMD f15h-f17h based
5865 unret,nosmt - Like unret, but will disable SMT when STIBP
5897 ro [KNL] Mount root device read-only on boot
5900 on Mark read-only kernel memory as read-only (default).
5901 off Leave read-only kernel memory writable for debugging.
5902 full Mark read-only kernel memory and aliases as read-only
5909 debug-uart get routed to the D+ and D- pins of the usb
5914 see the early_lookup_bdev comment in
5915 block/early-lookup.c for details.
5920 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
5931 rootwait= [KNL] Maximum time (in seconds) to wait for root device
5940 rw [KNL] Mount root device read-write on boot
5942 S [KNL] Run init in single mode
5948 in an IOTLB flush. Default is lazy flushing before
5960 and so on. As a special case a factor of 0 imposes no
5971 incurs a small amount of overhead in the scheduler
5994 to 10 seconds for built-in smp_call_function()
5999 up to the chosen limit in seconds. Zero (the
6001 that requesting even small non-zero numbers of
6002 seconds can result in RCU CPU stall warnings,
6008 The default of -1 specifies a number of kthreads
6013 test before initiating CPU-hotplug operations.
6017 CPU-hotplug operations. Specifying zero (which
6018 is the default) disables CPU-hotplug operations.
6024 Non-zero values are useful for automated tests.
6047 "wait" parameter. A value of -1 selects the
6048 default if all other weights are -1. However,
6050 value of -1 will instead select a weight of zero.
6055 non-zero "wait" parameter. See weight_single.
6068 non-zero "wait" parameter. See weight_single
6080 non-zero "wait" parameter. See weight_single
6084 Specify the MCLK divider for Intel SoundWire buses in
6087 skew_tick= [KNL,EARLY] Offset the periodic timer tick per cpu to mitigate
6091 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
6092 1 -- enable.
6103 0 -- disable.
6104 1 -- enable.
6107 serialnumber [BUGS=X86-32]
6109 sev=option[,option...] [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
6117 to set it to "all" by meaning -- no limit here.
6127 may poison objects when not in use. Also tracks the
6163 allocs to different slabs, especially in hardened
6176 in the slab allocator. The default is for memory
6180 in the slab fastpaths but gains more accurate
6182 interconnects in NUMA systems.
6190 Specify the period of time in milliseconds
6198 using the csdlock_debug- kernel parameter.
6203 system. By default, let CSD-lock acquisition
6205 for this value provides a 5-minute timeout.
6207 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
6208 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
6209 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
6210 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
6211 smsc-ircc2.ircc_irq= [HW] IRQ line
6212 smsc-ircc2.ircc_dma= [HW] DMA channel
6213 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
6223 Default: -1 (no limit)
6226 [KNL] Should the soft-lockup detector generate panics.
6229 A value of 1 instructs the soft-lockup detector
6230 to panic the machine when a soft-lockup occurs. It is
6233 respective build-time switch to that functionality.
6236 [KNL] Should the soft-lockup detector generate
6241 See Documentation/admin-guide/laptops/sonypi.rst
6248 on - (default) Enable the HW or SW mitigation as
6251 vmexit - On systems which don't have the HW mitigation
6254 protected from VM-originated BHI attacks, but
6256 off - Disable the mitigation.
6263 on - unconditionally enable, implies
6265 off - unconditionally disable, implies
6267 auto - kernel detects whether your CPU model is
6284 retpoline - replace indirect branches
6285 retpoline,generic - Retpolines
6286 retpoline,lfence - LFENCE; indirect branch
6287 retpoline,amd - alias for retpoline,lfence
6288 eibrs - Enhanced/Auto IBRS
6289 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
6290 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
6291 ibrs - use IBRS to protect kernel
6301 on - Unconditionally enable mitigations. Is
6304 off - Unconditionally disable mitigations. Is
6307 prctl - Indirect branch speculation is enabled,
6313 - Like "prctl" above, but only STIBP is
6319 - Same as "prctl" above, but all seccomp
6324 - Like "seccomp" above, but only STIBP is
6329 auto - Kernel selects the mitigation depending on
6340 off - Disable mitigation
6341 microcode - Enable microcode mitigation only
6342 safe-ret - Enable sw-only safe RET mitigation (default)
6343 ibpb - Enable mitigation by issuing IBPB on
6345 ibpb-vmexit - Issue IBPB only on VMEXIT
6346 (cloud-specific mitigation)
6354 as "Speculative Store Bypass" in which recent stores
6361 In vulnerable processors, the speculatively forwarded
6362 store can be used in a cache side channel attack, for
6371 on - Unconditionally disable Speculative Store Bypass
6372 off - Unconditionally enable Speculative Store Bypass
6373 auto - Kernel detects whether the CPU model contains an
6379 prctl - Control Speculative Store Bypass per thread
6383 seccomp - Same as "prctl" above, but all seccomp threads
6391 on,auto - On Power8 and Power9 insert a store-forwarding
6395 off - No action.
6405 boundaries will result in an alignment check exception
6409 off - not enabled
6411 warn - the kernel will emit rate-limited warnings
6417 enabled in hardware.
6419 fatal - the kernel will send SIGBUS to applications
6422 both features are enabled in hardware.
6424 ratelimit:N -
6432 If an #AC exception is hit in the kernel or in
6433 firmware (i.e. not while executing in user mode)
6434 the kernel will oops in either "warn" or "fatal"
6444 Certain CPUs are vulnerable to an MDS-like
6452 result in reduced throughput from /dev/urandom.
6464 This kernel-boot parameter defaults to 128,
6465 but takes effect only when the low-order four
6482 instead of the compile-time CONFIG_NR_CPUS.
6486 grace-period sequence counter wrap for the
6487 srcu_data structure's ->srcu_gp_seq_needed field.
6488 The greater the number of bits set in this kernel
6502 Specifies the number of no-delay instances
6509 Specifies the per-grace-period phase, number of
6510 non-sleeping polls of readers. Beyond this limit,
6516 Specifies number of microseconds of non-sleeping
6517 delay between each non-sleeping poll of readers.
6520 Specifies the number of update-side contention
6525 set for contention-based conversions to occur.
6535 force-on: Unconditionally enable mitigation for
6537 force-off: Unconditionally disable mitigation for
6539 kernel: Always enable mitigation in the
6542 interest in being mitigated too.
6546 is in page units and it defines how many pages prior
6548 growing up) the main stack are reserved for no other
6560 stacktrace_filter=[function-list]
6562 will trace at boot up. function-list is a comma-separated
6564 time by the stack_trace_filter file in the debugfs
6570 Set the STI (builtin display/keyboard on the HP-PARISC
6572 as the initial boot-console.
6573 See also comment in drivers/video/console/sticore.c.
6576 See comment in drivers/video/console/sticore.c.
6591 Limits the number of kernel HPT entries in the hash
6604 originate from a privileged port (i.e. a port in the
6615 process in parallel from a single connection.
6616 The default value is 0 (no limit).
6632 to global on non-NUMA machines)
6643 suspend.pm_test_delay=
6644 [SUSPEND]
6645 Sets the number of seconds to remain in a suspend test
6657 <int> -- Number of I/O TLB slabs
6658 <int> -- Second integer after comma. Number of swiotlb
6661 force -- force using of bounce buffers even if they
6663 noforce -- Never use bounce buffers (for debugging)
6672 are reported in the kernel log. Sysctls registered
6678 Ignore sysrq setting - this boot parameter will
6686 cache size. See Documentation/networking/ip-sysctl.rst
6691 test_suspend= [SUSPEND]
6693 Specify "mem" (for Suspend-to-RAM) or "standby" (for
6694 standby suspend) or "freeze" (for suspend type freeze)
6698 wakeup-capable RTC alarm.
6704 -1: disable all active trip points in all thermal zones
6708 -1: disable all critical trip points in all thermal zones
6715 -1: disable all passive trip points
6721 <deci-seconds>: poll all this frequency
6722 0: no polling (default)
6725 Format: <size>[KMG],<size>[KMG]:<state>;<size>[KMG]-<size>[KMG]:<state>
6730 See Documentation/admin-guide/mm/transhuge.rst for more
6738 Format: <size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy>
6744 See Documentation/admin-guide/mm/transhuge.rst for more
6756 Prevent the CPU-hotplug component of torturing
6760 Dump the ftrace buffer at torture-test shutdown,
6761 even if there were no errors. This can be a
6764 with rotating-rust storage.
6769 disables verbose-printk() sleeping.
6772 Duration of each verbose-printk() sleep in jiffies.
6776 access, or interposers in the bus by the means of
6778 TPM2_PCR_Extend command. Consider this in a situation
6785 Specify that at suspend time, the tpm driver
6797 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
6809 tp_printk kernel cmdline option has no effect.
6835 local - Use the per CPU time stamp counter
6838 in sync between CPUs.
6839 global - Event time stamps are synchronize across
6842 counter - Simple counting of events (1, 2, ..)
6846 uptime - Use jiffies as the time stamp.
6847 perf - Use the same clock that perf uses.
6848 mono - Use ktime_get_mono_fast_ns() for time stamps.
6849 mono_raw - Use ktime_get_raw_fast_ns() for time
6851 boot - Use ktime_get_boot_fast_ns() for time stamps.
6855 trace_event=[event-list]
6856 [FTRACE] Set and start specified trace events in order
6857 to facilitate early boot debugging. The event-list is a
6858 comma-separated list of trace events to enable. See
6861 trace_instance=[instance-info]
6862 [FTRACE] Create a ring buffer instance early in boot up.
6863 This will be listed in:
6886 traceoff - Have the tracing instance tracing disabled after it is created.
6887 traceprintk - Have trace_printk() write into this trace instance
6908 and place the ring buffer in this memory. Note that due to KASLR, the
6932 trace_options=[option-list]
6934 The option-list is a comma delimited list of options
6948 trace_trigger=[trigger-list]
6964 See also "Event triggers" in Documentation/trace/events.rst
6971 file located in /sys/kernel/tracing/
6985 See Documentation/admin-guide/mm/transhuge.rst
6992 See Documentation/admin-guide/mm/transhuge.rst
7000 - "tpm"
7001 - "tee"
7002 - "caam"
7003 - "dcp"
7013 - "kernel"
7014 - the same value as trusted.source: "tpm" or "tee"
7015 - "default"
7016 If not specified, "default" is used. In this case,
7020 This is intended to be used in combination with
7025 This is intended to be used in combination with
7028 having this key zero'ed is acceptable. E.g. in testing
7036 high-resolution timer mode on older hardware, and in
7046 in situations with strict latency requirements (where
7067 Extensions (TSX) feature in Intel processors that
7072 on - Enable TSX on the system. Although there are
7075 several previous speculation-related CVEs, and
7079 off - Disable TSX on the system. (Note that this
7087 auto - Disable TSX if X86_BUG_TAA is present,
7092 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7098 Similar to Micro-architectural Data Sampling (MDS)
7105 In vulnerable processors, the speculatively forwarded
7106 data can be used in a cache side channel attack, to
7113 full - Enable TAA mitigation on vulnerable CPUs
7116 full,nosmt - Enable TAA mitigation and disable SMT on
7119 vulnerable to cross-thread TAA attacks.
7120 off - Unconditionally disable TAA mitigation
7122 On MDS-affected machines, tsx_async_abort=off can be
7124 are mitigated with the same mechanism so in order to disable
7134 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7140 See also Documentation/input/devices/joystick-parport.rst
7142 udbg-immortal [PPC] When debugging early kernel crashes that
7148 Set number of hash buckets for UDP/UDP-Lite connections
7150 uhci-hcd.ignore_oc=
7152 Some badly-designed motherboards generate lots of
7161 unwind_debug [X86-64,EARLY]
7169 (default -1 = authorized (same as 1),
7174 [USB] The autosuspend time delay (in seconds) used
7175 for newly-detected USB devices (default 2). This
7184 [USB] Maximum number of bytes to snoop in each URB
7195 [USB] Memory limit (in MB) for buffers allocated by
7203 [USB] Specifies timeout for the initial 64-byte
7204 USB_REQ_GET_DESCRIPTOR request in milliseconds
7210 [USB] A list of quirk entries to augment the built-in
7213 VendorID:ProductID:Flags. The IDs are 4-digit hex
7215 will change the built-in quirk; setting it if it is
7220 a 255-byte read);
7224 Set-Interface requests);
7240 require the interval in microframes (1
7243 (bInterval-1).
7247 variable used in the calculation);
7261 to be disconnected before suspend to
7281 usb-storage.delay_use=
7282 [UMS] The delay in seconds before a new device is
7284 Optionally the delay in milliseconds if the value has
7288 usb-storage.quirks=
7290 override the built-in unusual_devs list. List
7293 and Product ID values (4-digit hex numbers) and
7295 to a common usb-storage quirk flag as follows:
7337 medium is write-protected).
7339 even if the device claims no cache,
7346 1 - undefined instruction events
7347 2 - system calls
7348 4 - invalid data aborts
7349 8 - SIGSEGV faults
7350 16 - SIGBUS faults
7356 nohigh = do not allocate PTE pages in
7366 vdso32= [X86] Control the 32-bit vDSO
7367 vdso32=1: enable 32-bit VDSO
7368 vdso32=0 or vdso32=2: disable 32-bit VDSO
7378 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
7409 vga= [BOOT,X86-32] Select a particular video mode
7411 Documentation/admin-guide/svga.rst.
7426 - Disable all of the above options
7450 vsyscall= [X86-64,EARLY]
7453 code). Most statically-linked binaries and older
7477 see VGA-softcursor.txt. Default: 2 = underline.
7482 This is a 16-member array composed of values
7483 ranging from 0-255.
7488 This is a 16-member array composed of values
7489 ranging from 0-255.
7494 This is a 16-member array composed of values
7495 ranging from 0-255.
7500 Set system-wide default UTF-8 mode for all tty's.
7501 Default is 1, i.e. UTF-8 mode is enabled for all
7506 Format=<-1|0|1>
7507 Set system-wide default for whether a cursor
7508 is shown on new VTs. Default is -1,
7513 vt.italic= [VT] Default color for italic text; 0-15.
7516 vt.underline= [VT] Default color for underlined text; 0-15.
7520 see Documentation/watchdog/watchdog-parameters.rst
7521 or other driver-specific files in the
7527 threshold in seconds. The soft lockup detector
7534 to use in unbound workqueues.
7535 Format: <cpu-list>
7544 duration in seconds. The default value is 30 and
7556 Per-cpu work items which run for longer than this
7559 them from noticeably delaying other per-cpu work
7570 intensive_threshold_us repeatedly. In order to prevent
7577 Per-cpu workqueues are generally preferred because
7579 locality; unfortunately, per-cpu workqueues tend to
7582 Enabling this makes the per-cpu workqueues which
7595 information, see the Affinity Scopes section in
7596 Documentation/core-api/workqueue.rst.
7606 on the local CPU. This guarantee is no longer true
7609 forces round-robin CPU selection to flush out
7617 on - Enable writecombine, use WUC for ioremap_wc()
7618 off - Disable writecombine, use SUC for ioremap_wc()
7620 x2apic_phys [X86-64,APIC,EARLY] Use x2apic physical mode instead of
7624 xen_512gb_limit [KNL,X86-64,XEN]
7634 ide-disks -- unplug primary master IDE devices
7635 aux-ide-disks -- unplug non-primary-master IDE devices
7636 nics -- unplug network devices
7637 all -- unplug all emulated devices (NICs and IDE disks)
7638 unnecessary -- unplugging emulated devices is
7641 never -- do not unplug even if version check succeeds
7651 debug data in case of multicall errors.
7655 Select whether to always use non-faulting (safe) MSR
7661 run as generic HVM guest with no PV drivers.
7675 xen_timer_slop= [X86-64,XEN,EARLY]
7676 Set the timer slop (in nanoseconds) for the virtual Xen
7683 The time (in seconds) to wait before giving up to boot
7684 in case initial ballooning fails to free enough memory.
7690 How long to delay EOI handling in case of event
7700 preferred over the 2-level event handling, as it is
7717 xive.store-eoi=off [PPC]
7723 xhci-hcd.quirks [USB,KNL]
7726 consulted in header drivers/usb/host/xhci.h.