Lines Matching +full:use +full:- +full:advanced +full:- +full:sector +full:- +full:protection
13 Advanced Configuration and Power Interface
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
39 2: use 2nd APIC table, if available
40 1,0: use 1st APIC table
45 If set to vendor, prefer vendor-specific driver
48 If set to video, use the ACPI video.ko driver.
49 If set to native, use the device's native backlight mode.
53 force FADT to use 32 bit addresses rather than the
55 bit addresses for force ACPI ignore these and use
77 Documentation/firmware-guide/acpi/debug.rst for more information about
125 use by PCI
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
244 For broken nForce2 BIOS resulting in XT-PIC timer.
253 as soon as the kernel's real-mode entry point is called.
275 suspend and resume to be ignored (use wisely).
278 Use timer override. For some broken Nvidia NF5 boards
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
314 and you need to use tracing_snapshot() on boot up, and
315 do not want to use tracing_snapshot_alloc() as it needs
319 Allow execve() of 32-bit applications and setting of the
321 subset of the CPUs support 32-bit EL0. When this
322 parameter is present, the set of CPUs supporting 32-bit
324 and hot-unplug operations may be restricted.
326 See Documentation/arch/arm64/asymmetric-32bit.rst for more
329 amd_iommu= [HW,X86-64]
332 fullflush - Deprecated, equivalent to iommu.strict=1
333 off - do not initialize any AMD IOMMU found in
335 force_isolation - Force device isolation for all
340 force_enable - Force enable the IOMMU on platforms known
341 to be buggy with IOMMU enabled. Use this
343 pgtbl_v1 - Use v1 page table for DMA-API (Default).
344 pgtbl_v2 - Use v2 page table for DMA-API.
345 irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
346 nohugepages - Limit page-sizes used for v1 page-tables
348 v2_pgsizes_only - Limit page-sizes used for v1 page-tables
352 amd_iommu_dump= [HW,X86-64]
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.
372 Use amd_pstate with passive mode as a scaling driver.
378 Use amd_pstate_epp driver instance as the scaling driver,
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.
414 apic= [APIC,X86,EARLY] Advanced Programmable Interrupt Controller
418 when initialising the APIC and IO-APIC components.
419 For X86-32, this can also be used to specify an APIC
440 apm= [APM] Advanced Power Management
446 0 -- disable.
447 1 -- enable.
450 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
496 Use software keyboard repeat
498 audit= [KNL] Enable the audit sub-system
500 0 | off - kernel audit is disabled and can not be
502 unset - kernel audit is initialized but disabled and
504 1 | on - kernel audit is initialized and partially
517 0 - Disable the BAU.
518 1 - Enable the BAU.
519 unset - Disable the BAU.
546 filesystems by naive storage tooling that don't use
558 See Documentation/block/cmdline-partition.rst
572 See Documentation/admin-guide/bootconfig.rst
577 bttv.pll= See Documentation/admin-guide/media/bttv.rst
580 bulk_remove=off [PPC] This parameter disables the use of the pSeries
586 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
605 inclusive. See arch/mips/include/asm/pgtable-bits.h
615 - foo isn't auto-mounted if you mount all cgroups in
617 - foo isn't visible as an individually mountable
619 - if foo is an optional feature then the feature is
625 Specifying "pressure" disables per-cgroup pressure
643 nosocket -- Disable socket memory accounting.
644 nokmem -- Disable kernel memory accounting.
645 nobpf -- Disable BPF memory accounting.
650 0 -- check protection applied by kernel (includes
651 any implied execute protection).
652 1 -- check protection requested by application.
664 numbers X. Note the Linux-specific bits are not necessarily
665 stable over kernel options, but the vendor-specific
685 force such clocks to be always-on nor does it reserve
689 information, see Documentation/driver-api/clk.rst.
691 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
700 Override the default clocksource and use the clocksource
708 [X86-32] pit,hpet,tsc;
715 [X86-64] hpet,tsc
721 architected timer so that code using WFE-based polling
735 clocksource-wdtest.holdoff= [KNL]
741 cma=nn[MG]@[start[MG][-end[MG]]]
752 Sets the size of kernel per-numa memory area for
754 per-numa CMA altogether. And If this option is not
756 With per-numa CMA enabled, DMA users on node nid will
783 com20020= [HW,NET] ARCnet - COM20020 chipset
787 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
791 ARCnet - COM90xx chipset (memory-mapped buffers)
810 tty<n> Use the virtual console device <n>.
814 Use the specified serial port. The options are of
820 See Documentation/admin-guide/serial-console.rst for more
826 Use the specified serial port on the serial core bus.
835 $ ls -d /sys/bus/serial-base/devices/*:*.*/tty/*
836 /sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0
841 is ready. The use of an earlycon parameter in addition to
849 Start an early, polled-mode console on the 8250/16550
852 MMIO inter-register address stride is either 8-bit
853 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
857 the h/w is not re-initialized.
859 hvc<n> Use the hypervisor console device <n>. This is for
863 Use to disable console output, i.e., to have kernel
884 syscall, or to executing "dmesg -S --raw" or to reading
908 disable the cpuidle sub-system
911 [CPU_IDLE] Name of the cpuidle governor to use.
914 disable the cpufreq sub-system
918 policy to use. This governor must be registered in the
922 [X86,EARLY] Delay for N microsec between assert and de-assert
943 like Hyper-V, PowerPC (fadump) and AMD SEV-SNP.
951 [KNL, X86-64, ARM64, RISCV, LoongArch] Select a region
954 See Documentation/admin-guide/kdump/kdump.rst for further details.
959 start-[end] where start and end are both
961 Documentation/admin-guide/kdump/kdump.rst for an example.
964 [KNL, X86-64, ARM64, RISCV, LoongArch] range could be
972 [KNL, X86-64, ARM64, RISCV, LoongArch] range under 4G.
978 for 32-bit devices won't run out. Kernel would try to allocate
981 --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
982 --> arm64: 128MiB
983 --> riscv: 128MiB
984 --> loongarch: 128MiB
992 [KNL] Disable crypto self-tests
1000 csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
1015 See also Documentation/input/devices/joystick-parport.rst
1021 boot sequence. If enabled, we use a weak hash instead
1022 of siphash to hash pointers. Use this option if you are
1025 insecure, please do not use on production kernels.
1028 [KNL] verbose locking self-tests
1031 self-tests.
1033 (no extra messages), setting it to -1 (all bits set)
1034 will print _a_lot_ more information - normally only
1045 amount of memory for normal system use. The maximum
1069 Format: { on, no-mount, off }
1071 no-mount:
1076 get a -EPERM as result when trying to register files
1080 Default value is set in build-time with a kernel configuration.
1092 Documentation/admin-guide/mm/hugetlbpage.rst.
1106 delayacct [KNL] Enable per-task delay accounting
1148 Disables the use of 1TB hash page table segments. This
1164 Disable Dynamic DMA Window support. Use this
1192 entries for DMA-API debugging code. One entry is
1193 required per DMA-API allocation. Use this if the
1194 DMA-API debugging code disables itself because the
1198 With this option the DMA-API debugging driver
1222 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1238 the EDID name. Each connector may use a unique EDID
1247 Control how the dt_cpu_ftrs device-tree binding is
1250 off: Do not use it, fall back to legacy cpu table.
1257 what data is available or for reverse-engineering.
1262 Documentation/admin-guide/dynamic-debug-howto.rst
1273 determined by stdout-path property in device tree's
1278 Start an early, polled-mode console on a Cadence
1289 Start an early, polled-mode console on the 8250/16550
1291 MMIO inter-register address stride is either 8-bit
1292 (mmio) or 32-bit (mmio32 or mmio32be).
1302 Start an early, polled-mode console on a pl011 serial
1306 the driver will use only 32-bit accessors to read/write
1315 Start an early, polled-mode console on a meson serial
1321 Start an early, polled-mode console on an msm serial
1327 Start an early, polled-mode console on an msm serial
1333 Start an early, polled-mode console on a serial port
1339 Start an early, polled-mode console on a serial port
1345 Use RISC-V SBI (Supervisor Binary Interface) for early
1348 smh Use ARM semihosting calls for early console.
1356 Use early console provided by serial driver available
1363 Start an early, polled-mode console on a lantiq serial
1370 Use early console provided by Freescale LP UART driver
1377 Start an early, polled-mode, output-only console on the
1382 Start an early, polled-mode console on the
1388 Start an early, polled-mode console on a Qualcomm
1396 coherent non-x86 systems that use system memory for
1401 Use early console provided by Freescale LINFlexD UART
1449 The optional "force" to "pciserial" enables use of a
1458 force: enforce the use of EDAC to report H/W event.
1486 Using this parameter you can use more than 50% of
1487 your efi variable storage. Use this parameter only if
1495 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1512 elanfreq= [X86-32]
1520 See Documentation/admin-guide/kdump/kdump.rst for details.
1536 0 -- permissive (log only, no denials).
1537 1 -- enforcing (deny and log).
1570 See also Documentation/fault-injection/.
1574 See Documentation/admin-guide/sysctl/net.rst for
1578 See Documentation/admin-guide/blockdev/floppy.rst.
1580 forcepae [X86-32]
1584 Warning: use of this parameter will taint the kernel
1587 fred= [X86-64]
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
1682 but use it only for ordering boot state clean
1684 on -- Create device links from firmware info and use it
1686 rpm -- Like "on", but also use to order runtime PM.
1699 strict -- Default. Continue waiting on consumers to
1701 timeout -- Give up waiting on consumers and call
1711 See also Documentation/input/devices/joystick-parport.rst
1715 gart_fix_e820= [X86-64,EARLY] disable the fix e820 for K8 GART
1739 gbpages [X86] Use GB pages for kernel direct mappings.
1741 gcov_persist= [GCOV] When non-zero (default), profiling data for
1748 Don't use this when you are not running on the
1751 gpio-mockup.gpio_mockup_ranges
1754 gpio-mockup.gpio_mockup_named_lines
1770 grcan.select= [HW] Select which physical interface to use.
1786 against bounds-checking flaws in the kernel's
1792 [KNL] Should the hard-lockup detector generate
1798 for 64-bit NUMA, off otherwise.
1806 corresponding firmware-first mode error processing
1814 protect_image Turn on image protection during restoration
1816 during restoration read-only).
1853 hpet= [X86-32,HPET] option to control HPET usage
1856 disable: disable HPET and use PIT instead
1870 number of pages to allocate per-node can be specified.
1871 See also Documentation/admin-guide/mm/hugetlbpage.rst.
1882 Documentation/admin-guide/mm/hugetlbpage.rst.
1893 boot-time allocation of gigantic hugepages is skipped.
1921 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1927 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1943 Set device-properties for ACPI-enumerated I2C-attached
1944 touchscreen, to e.g. fix coordinates of upside-down
1952 Omit "=<val>" entirely Set a boolean device-property
1953 Unsigned number Set a u32 device-property
1954 Anything else Set a string device-property
1957 i2c_touchscreen_props=GDIX1001:touchscreen-inverted-x:
1958 touchscreen-inverted-y
1960 i2c_touchscreen_props=MSSL1680:touchscreen-size-x=1920:
1961 touchscreen-size-y=1080:touchscreen-inverted-y:
1962 firmware-name=gsl1680-vendor-model.fw:silead,home-button
1967 (disabled by default, and as a pre-condition
1969 i8042.direct [HW] Put keyboard port into non-translated mode
1979 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
1983 suspend-to-ram transitions, only during s2r
2007 -1 -- never invert brightness
2008 0 -- machine default
2009 1 -- force brightness inversion
2011 ia32_emulation= [X86-64]
2013 When true, allows loading 32-bit programs and executing 32-bit
2038 idle=nomwait: Disable mwait for CPU C-states
2066 legacy only accept legacy-NaN binaries, if supported
2068 2008 only accept 2008-NaN binaries, if supported
2079 'relaxed' straps the emulator for both legacy-NaN and
2080 2008-NaN, whereas 'strict' enables legacy-NaN only on
2089 Ignore loglevel setting - this will print /all/
2107 ima_appraise_tcb [IMA] Deprecated. Use ima_policy= instead.
2112 Use the canonical format for the binary runtime
2148 ima_tcb [IMA] Deprecated. Use ima_policy= instead.
2156 Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" |
2157 "ima-sigv2" }
2158 Default: "ima-ng"
2190 initcall_blacklist= [KNL] Do not execute a comma-separated list of
2191 initcall functions. Useful for debugging built-in
2224 init_pkru= [X86] Specify the default memory protection keys rights
2236 0 -- basic integrity auditing messages. (Default)
2237 1 -- additional integrity auditing messages.
2248 this case, gfx device will use physical address for
2261 Disallow use of the Intel IOMMU scalable mode.
2265 could harm performance of some high-throughput
2274 1 to 9 specify maximum depth of C-state.
2281 Use intel_pstate driver to bypass the scaling
2283 algorithms for p-state selection. There are two
2284 P-state selection algorithms provided by
2287 on whether or not the hardware managed P-states
2291 Use intel_pstate as a scaling driver, but configure it
2294 used along with the hardware-managed P-states (HWP)
2298 in favor of acpi-cpufreq. Forcing the intel_pstate driver
2299 instead of acpi-cpufreq may disable platform features, such
2301 P-States information being indicated to OSPM and therefore
2304 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
2317 Allow per-logical-CPU P-State performance control limits using
2320 intremap= [X86-64,Intel-IOMMU,EARLY]
2325 BIOS x2APIC opt-out request will be ignored
2337 Don't initialize and use any kind of IOMMU.
2340 Force the use of the hardware IOMMU even when
2355 Use software bounce buffering (SWIOTLB) (default for
2368 AMD Gart HW IOMMU-specific options:
2380 Don't use IOMMU fullflush.
2387 Do scatter-gather (SG) merging. Implies "force"
2391 Don't do scatter-gather (SG) merging.
2397 Don't initialize the AGP driver and use full aperture.
2404 0 - Try to allocate a 32-bit DMA address first, before
2406 1 - Allocate directly from the full usable range,
2408 greater than 32-bit addressing.
2412 0 - Lazy mode.
2413 Request that DMA unmap operations use deferred
2418 1 - Strict mode.
2421 unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
2423 legacy driver-specific options takes precedence.
2428 0 - Use IOMMU translation for DMA.
2429 1 - Bypass the IOMMU for DMA.
2430 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2432 io7= [HW] IO7 for Marvel-based Alpha systems
2447 See Documentation/admin-guide/nfs/nfsroot.rst.
2478 that use the kernel as a bootloader, and thus want
2483 Enables support for pseudo-NMIs in the kernel. This
2502 [Deprecated - use cpusets instead]
2503 Format: [flag-list,]<cpu-list>
2528 advised to use cpusets instead to disable scheduler load
2536 "number of CPUs in system - 1".
2562 The format of <cpu-list> is described above.
2566 ivrs_ioapic [HW,X86-64]
2567 Provide an override to the IOAPIC-ID<->DEVICE-ID
2571 For example, to map IOAPIC-ID decimal 10 to
2577 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2580 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2584 ivrs_hpet [HW,X86-64]
2585 Provide an override to the HPET-ID<->DEVICE-ID
2589 For example, to map HPET-ID decimal 10 to
2595 * To map HPET-ID decimal 0 to PCI device 00:14.0
2598 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2602 ivrs_acpihid [HW,X86-64]
2603 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2607 For example, to map UART-HID:UID AMD0020:0 to
2613 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2616 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2640 the kernel for non-movable allocations. The requested
2650 subsystem. Note that allocations like PTEs-from-HighMem
2651 still use the HighMem zone if it exists, and the Normal
2658 for non-movable allocations and remaining memory is used
2669 gdb or control-c on the dbgp connection. When
2670 not using this parameter you use sysrq-g to break into
2675 or a supported polling keyboard driver (non-usb).
2685 characters and can work in polling mode, you can use
2686 this parameter to tell kgdb to use it as a backend
2702 Configure the RouterBoard 532 series on-chip
2705 kmemleak= [KNL,EARLY] Boot-time kmemleak enable/disable
2711 kprobe_event=[probe-list]
2713 The probe-list is a semicolon delimited list of probe
2743 execution by eliminating the write-protection faults
2770 virtualization on-demand when creating and destroying
2778 is that doing so may interfere with using out-of-tree
2805 back to huge pages. If the value is a non-zero N, KVM will
2810 kvm-amd.nested= [KVM,AMD] Control nested virtualization feature in
2813 kvm-amd.npt= [KVM,AMD] Control KVM's use of Nested Page Tables,
2814 a.k.a. Two-Dimensional Page Tables. Default is 1
2818 kvm-arm.mode=
2824 nvhe: Standard nVHE-based mode, without support for
2831 nested: VHE-based mode with support for nested
2839 command-line.
2843 kvm-arm.vgic_v3_group0_trap=
2844 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-0
2847 kvm-arm.vgic_v3_group1_trap=
2848 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-1
2851 kvm-arm.vgic_v3_common_trap=
2855 kvm-arm.vgic_v4_enable=
2856 [KVM,ARM,EARLY] Allow use of GICv4 for direct
2859 kvm-arm.wfe_trap_policy=
2868 kvm-arm.wfi_trap_policy=
2885 kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables,
2886 a.k.a. Two-Dimensional Page Tables. Default is 1
2890 kvm-intel.emulate_invalid_guest_state=
2892 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2898 kvm-intel.flexpriority=
2899 [KVM,Intel] Control KVM's use of FlexPriority feature
2903 kvm-intel.nested=
2907 kvm-intel.unrestricted_guest=
2908 [KVM,Intel] Control KVM's use of unrestricted guest
2913 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2914 CVE-2018-3620.
2925 kvm-intel.vpid= [KVM,Intel] Control KVM's use of Virtual Processor
2945 on - enable the interface for the mitigation
2950 The kernel PTE inversion protection is unconditionally
3010 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
3016 lapic [X86-32,APIC,EARLY] Enable the local APIC even if BIOS
3019 lapic= [X86,APIC] Do not use TSC deadline
3020 value for LAPIC timer one-shot implementation. Default
3039 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
3043 libata.force= [LIBATA] Force configurations. The format is a comma-
3055 first fan-out link behind PMP device. It does not
3069 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
3076 * rstonce: only attempt one reset during hot-unplug
3099 * atapi_mod16_dma: Enable the use of ATAPI DMA for
3102 * [no]dmalog: Enable or disable the use of the
3119 * external: Mark port as external (hotplug-capable).
3173 Specify the number of self-propagating call_rcu()
3181 occasional long-duration lock hold time. Defaults
3192 Set the number of locking read-acquisition kthreads.
3197 Set the number of locking write-acquisition kthreads.
3200 Set time (s) after boot for CPU-hotplug testing.
3203 Set time (s) between CPU-hotplug operations, or
3204 zero to disable CPU-hotplug testing.
3207 Do periodic testing of real-time lock priority
3212 non-real-time spinlocks, due to their disabling
3213 of preemption. Note that non-realtime mutexes
3226 Set task-shuffle interval (jiffies). Shuffling
3227 tasks allows some CPUs to go into dyntick-idle
3232 is useful for hands-off automated testing.
3251 Run the write-side locktorture kthreads at
3252 sched_set_fifo() real-time priority.
3270 7 (KERN_DEBUG) debug-level messages
3282 logo.nologo [FB] Disables display of the built-in Linux logo.
3287 lp=0 [LP] Specify parallel ports to use, e.g,
3300 an IEEE 1284-compliant printer is attached; if
3306 time-consuming boot-time autodetection (up to 250 ms per
3326 Example: machtype=lemote-yeeloong-2f-7inch
3338 (loop.max_loop) unconditionally pre-created at init time. The default
3341 devices can be requested on-demand with the
3342 /dev/loop-control interface.
3344 mce= [X86-{32,64}]
3381 do not opt-in to Local MCE delivery. Use legacy method
3402 don't overwrite the bios-set CMCI threshold. This boot
3411 force-enable recoverable machine check code paths
3417 See Documentation/admin-guide/md.rst.
3424 Control mitigation for the Micro-architectural Data
3439 full - Enable MDS mitigation on vulnerable CPUs
3440 full,nosmt - Enable MDS mitigation and disable
3442 off - Unconditionally disable MDS mitigation
3444 On TAA-affected machines, mds=off can be prevented by
3453 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3468 [ARC,MICROBLAZE] - the limit applies only to low memory,
3471 [ARM64] - only limits memory covered by the linear
3474 [X86] Work as limiting max address. Use together
3484 [ARM,MIPS,EARLY] - override the memory layout
3491 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3498 per-device physically contiguous DMA buffers.
3506 See Documentation/admin-guide/mm/memory-hotplug.rst.
3531 Example: Exclude memory from 0x18690000-0x1869ffff
3545 memmap=<size>%<offset>-<oldtype>+<newtype>
3547 from <oldtype> to <newtype>. If "-<oldtype>" is left
3562 repeatable BIOS-originated corruption always
3563 affects the same memory, you can use memmap=
3569 use. Use this parameter to scan for
3574 seconds. Use this parameter to check at some
3606 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3612 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
3616 s2idle - Suspend-To-Idle
3617 shallow - Power-On Suspend or equivalent (if supported)
3618 deep - Suspend-To-RAM or equivalent (if supported)
3619 See Documentation/admin-guide/pm/sleep-states.rst.
3621 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
3637 0 - The attached screen is the 3.5" TFT
3638 1 - The attached screen is the 7" TFT
3639 2 - The VGA Shield is attached (1024x768)
3643 b - Enable backlight. The TFT backlight pin will be
3647 c - Enable the s3c camera interface.
3648 t - Reserved for enabling touchscreen support. The
3652 https://repo.or.cz/w/linux-2.6/mini2440.git
3657 arch-independent options, each of which is an
3658 aggregation of existing arch-specific options.
3687 ssbd=force-off [ARM64]
3700 have other ways of avoiding SMT-based attacks.
3735 full - Enable mitigation on vulnerable CPUs
3737 full,nosmt - Enable mitigation and disable SMT on
3740 off - Unconditionally disable mitigation
3753 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3763 [KNL] When set to true, modules will use async probing
3765 specific module, use the module specific control that
3783 module_blacklist= [KNL] Do not load a comma-separated list of
3808 movable_node [KNL,EARLY] Boot-time switch to make hotplugable memory
3812 allocations. Use with caution!
3815 Format: <name>,<region-number>,<size>,<offset>
3818 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3824 [HW] Make the MicroTouch USB driver use raw coordinates
3848 multitce=off [PPC] This parameter disables the use of the pSeries
3857 something different and driver-specific.
3897 [NFS] enable 64-bit inode numbers.
3898 If zero, the NFS client will fake up a 32-bit inode
3900 of returning the full 64-bit number.
3901 The default is to return 64-bit inode numbers.
3925 scheme and the NFS level operations agree to use
3936 [NFS4] Specify an additional fixed unique ident-
3965 Setting this to value to 0 causes the kernel to use
3967 driver. A non-zero value sets the minimum interval
3972 server-to-server copies for which this server is
3984 server-to-server copy, knfsd temporarily mounts
3990 nfsaddrs= [NFS] Deprecated. Use ip= instead.
3991 See Documentation/admin-guide/nfs/nfsroot.rst.
3993 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3994 See Documentation/admin-guide/nfs/nfsroot.rst.
3997 See Documentation/admin-guide/nfs/nfsroot.rst.
4001 NMI stack-backtrace request.
4010 0 - turn hardlockup detector in nmi_watchdog off
4011 1 - turn hardlockup detector in nmi_watchdog on
4012 rNNN - configure the watchdog with raw perf event 0xNNN
4019 This is useful when you use a panic=... timeout and
4025 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
4029 no4lvl [RISCV,EARLY] Disable 4-level and 5-level paging modes.
4030 Forces kernel to use 3-level paging instead.
4032 no5lvl [X86-64,RISCV,EARLY] Disable 5-level paging mode. Forces
4033 kernel to use 4-level paging instead.
4037 noapic [SMP,APIC,EARLY] Tells the kernel to not make use of any
4057 it. Users could use console_suspend (usually
4068 no_entry_flush [PPC,EARLY] Don't flush the L1-D cache when entering the kernel.
4070 noexec32 [X86-64]
4071 This affects only 32-bit executables.
4072 noexec32=on: enable non-executable mappings (default)
4074 noexec32=off: disable non-executable mappings
4085 nofxsr [BUGS=X86-32] Disables x86 floating point extended
4087 legacy floating-point registers on task switch.
4089 nogbpages [X86] Do not use GB pages for kernel direct mappings.
4100 compared. However, if this command-line option is
4103 debugging the kernel. Please do not use on production
4109 busy wait in do_idle() and not use the arch_cpu_idle()
4117 nohpet [X86] Don't use the HPET timer.
4143 nointremap [X86-64,Intel-IOMMU,EARLY] Do not enable interrupt
4145 [Deprecated - use intremap=off]
4151 noirqdebug [X86-32] Disables the code which attempts to detect and
4161 no-kvmapf [X86,KVM,EARLY] Disable paravirtualized asynchronous page
4164 no-kvmclock [X86,KVM,EARLY] Disable paravirtualized KVM clock driver
4166 nolapic [X86-32,APIC,EARLY] Do not enable or use the local APIC.
4168 nolapic_timer [X86-32,APIC,EARLY] Do not use the local APIC timer.
4170 nomce [X86-32] Disable Machine Check Exception
4172 nomfgpt [X86-32] Disable Multi-Function General Purpose
4178 not load if they could possibly displace the pre-
4180 be available for use. The respective drivers will not
4181 perform display-mode changes or accelerated rendering.
4188 shutdown the other cpus. Instead use the REBOOT_VECTOR
4194 nopcid [X86-64,EARLY] Disable the PCID cpu feature.
4196 nopku [X86] Disable Memory Protection Keys CPU feature found
4199 nopti [X86-64,EARLY]
4212 norandmaps Don't use address space randomization. Equivalent to
4215 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
4221 no-scroll [VGA] Disables scrollback.
4222 This is required for the Braillex ib80-piezo Braille
4225 nosgx [X86-64,SGX,EARLY] Disables Intel SGX kernel support.
4245 nosoftlockup [KNL] Disable the soft-lockup detector.
4251 nospectre_bhb [ARM64,EARLY] Disable all mitigations for Spectre-BHB (branch
4264 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,LOONGARCH,EARLY]
4271 timer IRQ sources, i.e., the IO-APIC timer. This can
4276 [PPC,EARLY] Don't flush the L1-D cache after accessing user data.
4289 no-vmw-sched-clock
4291 scheduler clock and use the default one.
4294 soft-lockup and NMI watchdog (hard-lockup).
4298 nox2apic [X86-64,APIC,EARLY] Do not enable x2APIC mode.
4306 enabling legacy floating-point and sse state.
4309 register states. The kernel will fall back to use
4317 form of xsave area. The kernel will fall back to use
4328 n. So during boot up some boot time memory for per-cpu
4329 variables need be pre-allocated for later physical cpu
4356 soft-reserved memory partitioning.
4365 See Documentation/admin-guide/sysctl/vm.rst for details.
4368 See Documentation/core-api/debugging-via-ohci1394.rst for more
4383 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4387 boundary - index of last SLC block on Flex-OneNAND.
4389 lock - Configure if Flex-OneNAND boundary should be locked.
4408 page_owner= [KNL,EARLY] Boot-time page_owner enabling option.
4414 page_poison= [KNL,EARLY] Boot-time parameter changing the state of
4442 See Documentation/admin-guide/tainted-kernels.rst for
4461 Use this option carefully, maybe worth to setup a
4473 Use 'auto' to force the driver to use any
4495 Set to non-zero to probe primary and secondary ISA
4501 Set to non-zero if a chip is present that snoops speed
4524 bus and the use of other driver options may interfere
4543 bits to allow the use of the respective PIO modes.
4549 Set to non-zero to probe tertiary and further ISA
4555 platform configuration and the use of other driver
4565 Set to non-zero to probe QDI controllers. By default
4570 Set to non-zero to probe Winbond controllers. Use
4572 value given is the I/O port to use (typically 0x1b0).
4579 the use of the respective PIO modes. Bit 0 is for
4617 bios [X86-32] force use of PCI BIOS, don't access
4618 the hardware directly. Use this if your machine
4619 has a non-standard PCI host bridge.
4620 nobios [X86-32] disallow use of PCI BIOS, only direct
4621 hardware access methods are allowed. Use this
4624 conf1 [X86] Force use of PCI Configuration Access
4626 data in IO port 0xCFC, both 32-bit).
4627 conf2 [X86] Force use of PCI Configuration Access
4628 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4629 the function, IO port 0xCFA, also 8-bit, sets
4631 through ports 0xC000-0xCFFF).
4636 disable the use of PCIE advanced error reporting.
4638 root domains (aka PCI segments, in ACPI-speak).
4639 nommconf [X86] Disable use of MMCONFIG for PCI
4646 disable the use of MSI interrupts system-wide.
4651 primary IO-APIC for bridges that cannot disable
4658 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4667 Use with caution as certain devices share
4682 F0000h-100000h range.
4687 assign-busses [X86] Always assign all PCI bus
4696 noacpi [X86] Do not use ACPI for IRQ routing
4698 use_crs [X86] Use PCI host bridge window information
4700 is enabled by default. If you need to use this,
4703 If you need to use this, please report a bug.
4704 use_e820 [X86] Use E820 reservations to exclude parts of
4707 If you need to use this, please report a bug to
4708 <linux-[email protected]>.
4711 hardware. If you need to use this, please report
4712 a bug to <linux-[email protected]>.
4724 bfsort Sort PCI devices into breadth-first order.
4727 nobfsort Don't sort PCI devices into breadth-first order.
4729 tuning and use the BIOS-configured MPS defaults.
4739 configuration allows peer-to-peer DMA between
4742 that hot-added devices will work.
4757 A PCI-PCI bridge can be specified if resource
4763 for 4096-byte alignment.
4765 end-to-end CRC checking). Only effective if
4768 bios: Use BIOS/firmware settings. This is the
4795 noari do not use PCIe ARI.
4796 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4797 do not use PCIe ATS (and IOMMU device IOTLB).
4827 bit-0 : ACS Source Validation
4828 bit-1 : ACS Translation Blocking
4829 bit-2 : ACS P2P Request Redirect
4830 bit-3 : ACS P2P Completion Redirect
4831 bit-4 : ACS Upstream Forwarding
4832 bit-5 : ACS P2P Egress Control
4833 bit-6 : ACS Direct Translated P2P
4843 Validation unchanged from whatever power-up
4849 nomio [S390] Do not use MIO instructions.
4850 norid [S390] ignore the RID field and force use of
4855 system-wide.
4865 native Use native PCIe services (PME, AER, DPC, PCIe hotplug)
4867 use them. This may cause conflicts if the platform
4868 also tries to use these services.
4869 dpc-native Use native PCIe service for DPC only. May
4879 nomsi Do not use MSI for native PCIe PME signaling (this makes
4880 all PCIe root ports use INTx for all services).
4886 Keep all power-domains already enabled by bootloader on,
4897 Select which percpu first chunk allocator to use.
4904 pirq= [SMP,APIC] Manual mp-table setup
4905 See Documentation/arch/x86/i386/IO-APIC.rst.
4909 See also Documentation/admin-guide/parport.rst.
4928 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4937 { on | off | curr | res | no-curr | no-res }
4982 none - Limited to cond_resched() calls
4983 voluntary - Limited to cond_resched() and might_sleep() calls
4984 full - Any section that isn't explicitly preempt disabled
4988 lazy - Scheduler controlled. Similar to full but instead
4994 print-fatal-signals=
5000 coredump - etc.
5003 you might want to try "ulimit -i unlimited".
5015 or lockdep-detected issues (only if lock debug is on).
5024 on - unlimited logging to /dev/kmsg from userspace
5025 off - logging to /dev/kmsg disabled
5026 ratelimit - ratelimit the logging
5037 - 'always': traditional behavior always allows mem overrides.
5038 - 'ptrace': only allow mem overrides for active ptracers.
5039 - 'never': never allow mem overrides.
5043 Limit processor to maximum C-state
5047 Ignore the _CST method to determine C-states,
5054 Param: "schedule" - profile schedule points.
5055 Param: "kvm" - profile VM exits.
5056 Param: <number> - step/bucket size as a power of 2 for
5085 pstore.backend= Specify the name of the pstore backend to use
5087 pti= [X86-64] Control Page Table Isolation of user and
5092 on - unconditionally enable
5093 off - unconditionally disable
5094 auto - kernel detects whether your CPU model is
5100 [KNL] Number of legacy pty's. Overwrites compiled-in
5108 Disable RADIX GTSE feature and use hcall for TLB
5112 See Documentation/admin-guide/md.rst.
5115 See Documentation/admin-guide/blockdev/ramdisk.rst.
5120 [KNL,EARLY] Disable trusting the use of the CPU's
5125 [KNL,EARLY] Disable trusting the use of the a seed
5134 cross-syscall address exposures. This is only
5140 ras=option[,option,...] [KNL] RAS-specific options
5146 rcu_nocbs[=cpu-list]
5151 enable the no-callback CPU mode, which prevents
5156 "p" for RCU-preempt, "s" for RCU-sched, and "g"
5160 and real-time workloads. It can also improve
5164 list of CPUs is set to no-callback mode from boot.
5168 no-callback mode from boot but the mode may be
5179 This improves the real-time response for the
5190 Do only a one-line RCU CPU stall warning when
5191 there is an ongoing too-long CSD-lock wait.
5197 If triggered before the RCU grace-period machinery
5207 RCU grace-period cleanup.
5211 RCU grace-period initialization.
5215 RCU grace-period pre-initialization, that is,
5216 the propagation of recent CPU-hotplug changes up
5220 Set delay from grace-period initialization to
5233 soliciting quiescent-state help from
5245 Set the SCHED_FIFO priority of the RCU per-CPU
5248 and for the RCU grace-period kthreads (rcu_bh,
5250 set, valid values are 1-99 and the default is 1
5251 (the least-favored priority). Otherwise, when
5252 RCU_BOOST is not set, valid values are 0-99 and
5253 the default is zero (non-realtime operation).
5258 On callback-offloaded (rcu_nocbs) CPUs,
5261 use of the ->nocb_bypass list. However, in the
5262 common non-flooded case, RCU queues directly to
5263 the main ->cblist in order to avoid the extra
5264 overhead of the ->nocb_bypass list and its lock.
5266 a single jiffy, RCU pre-queues the callbacks into
5267 the ->nocb_bypass queue. The definition of "too
5271 On callback-offloaded (rcu_nocbs) CPUs, avoid
5284 batch limiting is re-enabled.
5288 RCU's force-quiescent-state scan will aggressively
5296 Set the page-cache refill delay (in milliseconds)
5297 in response to low-memory conditions. The range
5301 Set the shift-right count to use to compute
5302 the callback-invocation batch limit bl from
5309 Please note that this callback-invocation batch
5310 limit applies only to non-offloaded callback
5319 cache-to-cache transfer latencies.
5325 and for NUMA systems with large remote-access
5341 the wakeup overhead on the global grace-period
5343 each group's NOCB grace-period kthread.
5346 Cause the grace-period kthread to get an extra
5348 it should at force-quiescent-state time.
5361 this specifies an rcu_read_unlock()-time delay
5364 catching RCU pointer leaks, that is, buggy use
5365 of RCU-protected pointers after the relevant
5375 per-CPU rcuc kthreads. Defaults to a non-zero
5377 Specify rcutree.use_softirq=0 to use rcuc kthreads.
5392 use a call_rcu[_hurry]() path. Please note, this is for a
5404 grace-period primitives such as call_rcu().
5415 grace-period primitives.
5418 Set test-start holdoff period. The purpose of
5436 Test the double-argument variant of kfree_rcu().
5438 rcuscale.kfree_rcu_test_single, both the single-
5439 and double-argument variants are tested.
5442 Test the single-argument variant of kfree_rcu().
5444 rcuscale.kfree_rcu_test_double, both the single-
5445 and double-argument variants are tested.
5459 does not affect the data-collection interval,
5464 Set number of RCU readers. The value -1 selects
5466 "n" less than -1 selects N-n+1, where N is again
5467 the number of CPUs. For example, -2 selects N
5468 (the number of CPUs), -3 selects N+1, and so on.
5469 A value of "n" less than or equal to -N selects
5482 complete. This is useful for hands-off automated
5489 Write-side holdoff between grace periods,
5494 Additional write-side holdoff between grace
5512 for RCU grace-period forward-progress testing
5519 Specify the fraction of a CPU-stall-warning
5520 period to do tight-loop forward-progress testing.
5524 forward-progress tests.
5528 need_resched() during tight-loop forward-progress
5532 Use conditional/asynchronous update-side
5533 normal-grace-period primitives, if available.
5536 Use conditional/asynchronous update-side
5537 expedited-grace-period primitives, if available.
5540 Use conditional/asynchronous update-side
5541 normal-grace-period primitives that also take
5546 Use conditional/asynchronous update-side
5547 expedited-grace-period primitives that also take
5571 Use expedited update-side primitives, if available.
5574 Use normal (non-expedited) asynchronous
5575 update-side primitives, if available.
5578 Use polled update-side normal-grace-period
5582 Use polled update-side expedited-grace-period
5586 Use polled update-side normal-grace-period
5591 Use polled update-side expedited-grace-period
5615 Use normal (non-expedited) synchronous
5616 update-side primitives, if available. If all
5620 they are all non-zero.
5628 Leak an RCU-protected pointer out of the reader.
5643 Set number of RCU callback-offload togglers.
5648 callback-offload toggling attempts.
5651 Set number of RCU readers. The value -1 selects
5652 N-1, where N is the number of CPUs. A value
5653 "n" less than -1 selects N-n-2, where N is again
5654 the number of CPUs. For example, -2 selects N
5655 (the number of CPUs), -3 selects N+1, and so on.
5658 Enable debug-object double-call_rcu() testing.
5661 Set time (s) after boot for CPU-hotplug testing.
5664 Set time (jiffies) between CPU-hotplug operations,
5665 or zero to disable CPU-hotplug testing.
5669 by a high-priority FIFO real-time task. Set to
5678 second) between preemptions by a high-priority
5679 FIFO real-time task. This delay is mediated
5684 The number of times in a given read-then-exit
5685 episode that a set of read-then-exit kthreads
5690 read-then-exit testing episodes.
5693 A bit mask indicating which readers to use.
5695 are entered from low-order bit up, and are
5697 0x1 bit is normal readers, 0x2 NMI-safe readers,
5698 and 0x4 light-weight readers.
5701 Set task-shuffle interval (s). Shuffling tasks
5702 allows some CPUs to go into dyntick-idle mode
5707 is useful for hands-off automated testing.
5716 any other stall-related activity. Note that
5722 in scheduling-while-atomic splats.
5724 Use of this module parameter results in splats.
5741 grace-period kthread to test RCU CPU stall
5767 Test RCU's dyntick-idle handling. See also the
5822 Use expedited grace-period primitives, for
5826 real-time latency, and degrade energy efficiency.
5830 Use only normal grace-period primitives,
5833 real-time latency, CPU utilization, and
5835 increased grace-period latency. This parameter
5841 rcu_end_inkernel_boot() has been invoked), use
5842 only normal grace-period primitives. No effect
5848 post-boot attempt at an expedited RCU grace
5849 period to instead use normal non-expedited
5850 grace-period processing.
5858 set to the default value of -1.
5861 Set the minimum number of callback-queuing-time
5862 lock-contention events per jiffy required to
5863 cause the RCU Tasks flavors to switch to per-CPU
5866 the default value of -1.
5869 Set the number of callback queues to use for the
5871 of -1 allows this to be automatically (and
5873 for use in testing.
5879 number avoids disturbing real-time workloads,
5884 cancel laziness on that CPU. Use -1 to disable
5894 only printed prior to the stall-warning message
5942 force - Override the decision by the kernel to hide the
5952 E.g. to turn on cmt and turn off mba use:
5970 Use the ACPI RESET_REG in the FADT. If ACPI is not
5975 Use the CPU reboot vector for warm reset
5981 There are some built-in platform specific "quirks"
5982 - you may see: "reboot: <name> series board detected.
5986 built-in quirk table, and use the generic default
5990 Use efi reset_system runtime service. If EFI is not
5999 Use the keyboard controller. cold reset (default)
6002 Use a write to the PCI config space register 0xcf9 to
6019 Set test-start holdoff period. The purpose of
6025 Number of data elements to use for the forms of
6034 but the default has already reduced the per-pass
6039 Set number of readers. The default value of -1
6048 Set the read-side critical-section duration,
6052 Specify the read-protection implementation to test.
6078 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
6082 Reserve I/O ports or memory so the kernel won't use
6089 other subsystems can use to access it. This is typically
6108 reservetop= [X86-32,EARLY]
6125 See Documentation/power/swsusp-and-swap-files.rst
6141 AMD-based UNRET and IBPB mitigations alone do not stop
6143 sibling threads. For that reason, STIBP is used on pro-
6147 off - no mitigation
6148 auto - automatically select a migitation
6149 auto,nosmt - automatically select a mitigation,
6153 ibpb - On AMD, mitigate short speculation
6158 ibpb,nosmt - Like "ibpb" above but will disable SMT
6162 unret - Force enable untrained return thunks,
6163 only effective on AMD f15h-f17h based
6165 unret,nosmt - Like unret, but will disable SMT when STIBP
6197 ro [KNL] Mount root device read-only on boot
6200 on Mark read-only kernel memory as read-only (default).
6201 off Leave read-only kernel memory writable for debugging.
6202 full Mark read-only kernel memory and aliases as read-only
6209 debug-uart get routed to the D+ and D- pins of the usb
6215 block/early-lookup.c for details.
6240 rw [KNL] Mount root device read-write on boot
6256 The default is 1 meaning that one can concurrently use
6262 cost of significant additional memory use for tables.
6294 to 10 seconds for built-in smp_call_function()
6301 that requesting even small non-zero numbers of
6308 The default of -1 specifies a number of kthreads
6313 test before initiating CPU-hotplug operations.
6317 CPU-hotplug operations. Specifying zero (which
6318 is the default) disables CPU-hotplug operations.
6324 Non-zero values are useful for automated tests.
6336 Use use_cpus_read_lock() instead of the default
6345 The probability weighting to use for the
6347 "wait" parameter. A value of -1 selects the
6348 default if all other weights are -1. However,
6350 value of -1 will instead select a weight of zero.
6353 The probability weighting to use for the
6355 non-zero "wait" parameter. See weight_single.
6358 The probability weighting to use for the
6366 The probability weighting to use for the
6368 non-zero "wait" parameter. See weight_single
6372 The probability weighting to use for the
6378 The probability weighting to use for the
6380 non-zero "wait" parameter. See weight_single
6391 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
6392 1 -- enable.
6403 0 -- disable.
6404 1 -- enable.
6407 serialnumber [BUGS=X86-32]
6409 sev=option[,option...] [X86-64]
6415 Do not enable SEV-SNP (applies to host/hypervisor
6418 SEV-SNP guests.
6423 show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
6426 to set it to "all" by meaning -- no limit here.
6436 may poison objects when not in use. Also tracks the
6507 using the csdlock_debug- kernel parameter.
6512 system. By default, let CSD-lock acquisition
6514 for this value provides a 5-minute timeout.
6516 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
6517 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
6518 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
6519 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
6520 smsc-ircc2.ircc_irq= [HW] IRQ line
6521 smsc-ircc2.ircc_dma= [HW] DMA channel
6522 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
6528 (logical CPUs) to use per physical CPU on systems
6532 Default: -1 (no limit)
6535 [KNL] Should the soft-lockup detector generate panics.
6538 A value of 1 instructs the soft-lockup detector
6539 to panic the machine when a soft-lockup occurs. It is
6542 respective build-time switch to that functionality.
6545 [KNL] Should the soft-lockup detector generate
6550 See Documentation/admin-guide/laptops/sonypi.rst
6557 on - (default) Enable the HW or SW mitigation as
6560 vmexit - On systems which don't have the HW mitigation
6563 protected from VM-originated BHI attacks, but
6565 off - Disable the mitigation.
6572 on - unconditionally enable, implies
6574 off - unconditionally disable, implies
6576 auto - kernel detects whether your CPU model is
6593 retpoline - replace indirect branches
6594 retpoline,generic - Retpolines
6595 retpoline,lfence - LFENCE; indirect branch
6596 retpoline,amd - alias for retpoline,lfence
6597 eibrs - Enhanced/Auto IBRS
6598 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
6599 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
6600 ibrs - use IBRS to protect kernel
6610 on - Unconditionally enable mitigations. Is
6613 off - Unconditionally disable mitigations. Is
6616 prctl - Indirect branch speculation is enabled,
6622 - Like "prctl" above, but only STIBP is
6628 - Same as "prctl" above, but all seccomp
6633 - Like "seccomp" above, but only STIBP is
6638 auto - Kernel selects the mitigation depending on
6649 off - Disable mitigation
6650 microcode - Enable microcode mitigation only
6651 safe-ret - Enable sw-only safe RET mitigation (default)
6652 ibpb - Enable mitigation by issuing IBPB on
6654 ibpb-vmexit - Issue IBPB only on VMEXIT
6655 (cloud-specific mitigation)
6680 on - Unconditionally disable Speculative Store Bypass
6681 off - Unconditionally enable Speculative Store Bypass
6682 auto - Kernel detects whether the CPU model contains an
6688 prctl - Control Speculative Store Bypass per thread
6692 seccomp - Same as "prctl" above, but all seccomp threads
6700 on,auto - On Power8 and Power9 insert a store-forwarding
6704 off - No action.
6718 off - not enabled
6720 warn - the kernel will emit rate-limited warnings
6728 fatal - the kernel will send SIGBUS to applications
6733 ratelimit:N -
6753 Certain CPUs are vulnerable to an MDS-like
6773 This kernel-boot parameter defaults to 128,
6774 but takes effect only when the low-order four
6791 instead of the compile-time CONFIG_NR_CPUS.
6795 grace-period sequence counter wrap for the
6796 srcu_data structure's ->srcu_gp_seq_needed field.
6811 Specifies the number of no-delay instances
6818 Specifies the per-grace-period phase, number of
6819 non-sleeping polls of readers. Beyond this limit,
6825 Specifies number of microseconds of non-sleeping
6826 delay between each non-sleeping poll of readers.
6829 Specifies the number of update-side contention
6834 set for contention-based conversions to occur.
6844 force-on: Unconditionally enable mitigation for
6846 force-off: Unconditionally disable mitigation for
6854 override the default stack gap protection. The value
6869 stacktrace_filter=[function-list]
6871 will trace at boot up. function-list is a comma-separated
6879 Set the STI (builtin display/keyboard on the HP-PARISC
6881 as the initial boot-console.
6941 to global on non-NUMA machines)
6950 amount of memory reserved for use by the client.
6961 This parameter controls use of the Protected
6966 <int> -- Number of I/O TLB slabs
6967 <int> -- Second integer after comma. Number of swiotlb
6970 force -- force using of bounce buffers even if they
6972 noforce -- Never use bounce buffers (for debugging)
6987 Ignore sysrq setting - this boot parameter will
6995 cache size. See Documentation/networking/ip-sysctl.rst
7002 Specify "mem" (for Suspend-to-RAM) or "standby" (for
7007 wakeup-capable RTC alarm.
7013 -1: disable all active trip points in all thermal zones
7017 -1: disable all critical trip points in all thermal zones
7024 -1: disable all passive trip points
7030 <deci-seconds>: poll all this frequency
7034 Format: <size>[KMG],<size>[KMG]:<state>;<size>[KMG]-<size>[KMG]:<state>
7039 See Documentation/admin-guide/mm/transhuge.rst for more
7047 Format: <size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy>
7053 See Documentation/admin-guide/mm/transhuge.rst for more
7058 Specify if the kernel should make use of the cpu
7060 The scheduler will make use of this information and
7065 Prevent the CPU-hotplug component of torturing
7069 Dump the ftrace buffer at torture-test shutdown,
7073 with rotating-rust storage.
7078 disables verbose-printk() sleeping.
7081 Duration of each verbose-printk() sleep in jiffies.
7088 where TPM is heavily utilized by IMA, thus protection
7106 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
7144 local - Use the per CPU time stamp counter
7148 global - Event time stamps are synchronize across
7151 counter - Simple counting of events (1, 2, ..)
7155 uptime - Use jiffies as the time stamp.
7156 perf - Use the same clock that perf uses.
7157 mono - Use ktime_get_mono_fast_ns() for time stamps.
7158 mono_raw - Use ktime_get_raw_fast_ns() for time
7160 boot - Use ktime_get_boot_fast_ns() for time stamps.
7164 trace_event=[event-list]
7166 to facilitate early boot debugging. The event-list is a
7167 comma-separated list of trace events to enable. See
7170 To enable modules, use :mod: keyword:
7178 trace_instance=[instance-info]
7203 traceoff - Have the tracing instance tracing disabled after it is created.
7204 traceprintk - Have trace_printk() write into this trace instance
7212 can use that memory:
7249 trace_options=[option-list]
7251 The option-list is a comma delimited list of options
7265 trace_trigger=[trigger-list]
7302 See Documentation/admin-guide/mm/transhuge.rst
7309 See Documentation/admin-guide/mm/transhuge.rst
7316 See Documentation/admin-guide/mm/transhuge.rst
7324 - "tpm"
7325 - "tee"
7326 - "caam"
7327 - "dcp"
7337 - "kernel"
7338 - the same value as trusted.source: "tpm" or "tee"
7339 - "default"
7360 high-resolution timer mode on older hardware, and in
7362 [x86] noirqtime: Do not use TSC to do irq accounting.
7377 [x86] watchdog: Use TSC as the watchdog clocksource with
7384 tsc_early_khz= [X86,EARLY] Skip early TSC calibration and use the given
7396 on - Enable TSX on the system. Although there are
7399 several previous speculation-related CVEs, and
7403 off - Disable TSX on the system. (Note that this
7411 auto - Disable TSX if X86_BUG_TAA is present,
7416 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7422 Similar to Micro-architectural Data Sampling (MDS)
7437 full - Enable TAA mitigation on vulnerable CPUs
7440 full,nosmt - Enable TAA mitigation and disable SMT on
7443 vulnerable to cross-thread TAA attacks.
7444 off - Unconditionally disable TAA mitigation
7446 On MDS-affected machines, tsx_async_abort=off can be
7458 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7464 See also Documentation/input/devices/joystick-parport.rst
7466 udbg-immortal [PPC] When debugging early kernel crashes that
7472 Set number of hash buckets for UDP/UDP-Lite connections
7474 uhci-hcd.ignore_oc=
7476 Some badly-designed motherboards generate lots of
7485 unwind_debug [X86-64,EARLY]
7493 (default -1 = authorized (same as 1),
7499 for newly-detected USB devices (default 2). This
7527 [USB] Specifies timeout for the initial 64-byte
7534 [USB] A list of quirk entries to augment the built-in
7537 VendorID:ProductID:Flags. The IDs are 4-digit hex
7539 will change the built-in quirk; setting it if it is
7544 a 255-byte read);
7548 Set-Interface requests);
7553 (e.g morph devices), don't use reset);
7567 (bInterval-1).
7605 usb-storage.delay_use=
7612 usb-storage.quirks=
7614 override the built-in unusual_devs list. List
7617 and Product ID values (4-digit hex numbers) and
7619 to a common usb-storage quirk flag as follows:
7625 device capacity by one sector);
7626 d = NO_READ_DISC_INFO (don't use
7628 e = NO_READ_CAPACITY_16 (don't use
7630 f = NO_REPORT_OPCODES (don't use report opcodes
7636 sector if the number is odd);
7639 j = NO_REPORT_LUNS (don't use report luns
7641 k = NO_SAME (do not use WRITE_SAME, uas only)
7661 medium is write-protected).
7670 1 - undefined instruction events
7671 2 - system calls
7672 4 - invalid data aborts
7673 8 - SIGSEGV faults
7674 16 - SIGBUS faults
7690 vdso32= [X86] Control the 32-bit vDSO
7691 vdso32=1: enable 32-bit VDSO
7692 vdso32=0 or vdso32=2: disable 32-bit VDSO
7702 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
7722 <size> := size (can use standard suffixes
7733 vga= [BOOT,X86-32] Select a particular video mode
7735 Documentation/admin-guide/svga.rst.
7736 Use vga=ask for menu.
7750 - Disable all of the above options
7774 vsyscall= [X86-64,EARLY]
7777 code). Most statically-linked binaries and older
7778 versions of glibc use these calls. Because these
7791 them quite hard to use for exploits but
7801 see vga-softcursor.rst. Default: 2 = underline.
7806 This is a 16-member array composed of values
7807 ranging from 0-255.
7812 This is a 16-member array composed of values
7813 ranging from 0-255.
7818 This is a 16-member array composed of values
7819 ranging from 0-255.
7824 Set system-wide default UTF-8 mode for all tty's.
7825 Default is 1, i.e. UTF-8 mode is enabled for all
7830 Format=<-1|0|1>
7831 Set system-wide default for whether a cursor
7832 is shown on new VTs. Default is -1,
7837 vt.italic= [VT] Default color for italic text; 0-15.
7840 vt.underline= [VT] Default color for underlined text; 0-15.
7844 see Documentation/watchdog/watchdog-parameters.rst
7845 or other driver-specific files in the
7858 to use in unbound workqueues.
7859 Format: <cpu-list>
7880 Per-cpu work items which run for longer than this
7883 them from noticeably delaying other per-cpu work
7901 Per-cpu workqueues are generally preferred because
7903 locality; unfortunately, per-cpu workqueues tend to
7906 Enabling this makes the per-cpu workqueues which
7916 Select the default affinity scope to use for unbound
7920 Documentation/core-api/workqueue.rst.
7933 forces round-robin CPU selection to flush out
7941 on - Enable writecombine, use WUC for ioremap_wc()
7942 off - Disable writecombine, use SUC for ioremap_wc()
7944 x2apic_phys [X86-64,APIC,EARLY] Use x2apic physical mode instead of
7948 xen_512gb_limit [KNL,X86-64,XEN]
7950 to use only up to 512 GB of RAM. The reason to do so is
7958 ide-disks -- unplug primary master IDE devices
7959 aux-ide-disks -- unplug non-primary-master IDE devices
7960 nics -- unplug network devices
7961 all -- unplug all emulated devices (NICs and IDE disks)
7962 unnecessary -- unplugging emulated devices is
7965 never -- do not unplug even if version check succeeds
7979 Select whether to always use non-faulting (safe) MSR
7995 to Xen, for use by other domains. Can be also changed at runtime
7999 xen_timer_slop= [X86-64,XEN,EARLY]
8024 preferred over the 2-level event handling, as it is
8026 much higher. Default is on (use fifo events).
8034 natively use the XIVE interrupt controller. This option
8041 xive.store-eoi=off [PPC]
8042 By default on POWER10 and above, the kernel will use
8044 is active. This option allows the XIVE driver to use
8047 xhci-hcd.quirks [USB,KNL]