Lines Matching +full:allow +full:- +full:set +full:- +full:time
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
37 If set to vendor, prefer vendor-specific driver
40 If set to video, use the ACPI video.ko driver.
41 If set to native, use the device's native backlight mode.
42 If set to none, disable the ACPI backlight interface.
69 Documentation/firmware-guide/acpi/debug.rst for more information about
127 Format: <byte> or <bitmap-list>
130 Disable auto-serialization of AML methods
133 auto-serialization feature.
141 Disable installation of static SSDTs at early boot time
151 Ignore the ACPI-based watchdog interface (WDAT) and let
172 acpi_osi=! # disable all built-in OS vendor
174 acpi_osi=!! # enable all built-in OS vendor
236 For broken nForce2 BIOS resulting in XT-PIC timer.
245 as soon as the kernel's real-mode entry point is called.
251 on docking. So the default behaviour is to allow resume
262 sci_force_enable causes the kernel to set SCI_EN directly
283 See Documentation/sound/alsa-configuration.rst
286 Allow the default userspace alignment fault handler
290 align_va_addr= [X86-64]
292 allocating a VMA at process creation time. This option
295 CPU-intensive style benchmark, and it can vary highly in
298 32: only for 32-bit processes
299 64: only for 64-bit processes
300 on: enable for both 32- and 64-bit processes
301 off: disable for both 32- and 64-bit processes
311 Allow execve() of 32-bit applications and setting of the
313 subset of the CPUs support 32-bit EL0. When this
314 parameter is present, the set of CPUs supporting 32-bit
316 and hot-unplug operations may be restricted.
318 See Documentation/arch/arm64/asymmetric-32bit.rst for more
321 amd_iommu= [HW,X86-64]
324 fullflush - Deprecated, equivalent to iommu.strict=1
325 off - do not initialize any AMD IOMMU found in
327 force_isolation - Force device isolation for all
332 force_enable - Force enable the IOMMU on platforms known
335 pgtbl_v1 - Use v1 page table for DMA-API (Default).
336 pgtbl_v2 - Use v2 page table for DMA-API.
337 irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
339 amd_iommu_dump= [HW,X86-64]
345 amd_iommu_intr= [HW,X86-64]
348 legacy - Use legacy interrupt remapping mode.
349 vapic - Use virtual APIC mode, which allows IOMMU
351 This mode requires kvm-amd.avic=1.
388 Power management functions (SPARCstation-4/5 + deriv.)
390 Disable APC CPU standby support. SPARCstation-Fox does
391 not play well with APC CPU idle - disable it if you have
398 when initialising the APIC and IO-APIC components.
399 For X86-32, this can also be used to specify an APIC
419 apparmor= [APPARMOR] Disable or enable AppArmor at boot time
422 0 -- disable.
423 1 -- enable.
424 Default value is set via kernel config option.
426 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
433 Set instructions support
456 atkbd.set= [HW] Select keyboard code set
468 audit= [KNL] Enable the audit sub-system
470 0 | off - kernel audit is disabled and can not be
472 unset - kernel audit is initialized but disabled and
474 1 | on - kernel audit is initialized and partially
480 audit_backlog_limit= [KNL] Set the audit queue size limit.
487 0 - Disable the BAU.
488 1 - Enable the BAU.
489 unset - Disable the BAU.
516 See Documentation/block/cmdline-partition.rst
529 See Documentation/admin-guide/bootconfig.rst
534 bttv.pll= See Documentation/admin-guide/media/bttv.rst
539 at a time.
543 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
551 [NET] Specifies amount of time (in seconds) that
562 inclusive. See arch/mips/include/asm/pgtable-bits.h
572 - foo isn't auto-mounted if you mount all cgroups in
574 - foo isn't visible as an individually mountable
576 - if foo is an optional feature then the feature is
582 Specifying "pressure" disables per-cgroup pressure
600 nosocket -- Disable socket memory accounting.
601 nokmem -- Disable kernel memory accounting.
602 nobpf -- Disable BPF memory accounting.
604 checkreqprot= [SELINUX] Set initial checkreqprot flag value.
607 0 -- check protection applied by kernel (includes
609 1 -- check protection requested by application.
610 Default value is set via a kernel config option.
621 numbers X. Note the Linux-specific bits are not necessarily
622 stable over kernel options, but the vendor-specific
642 force such clocks to be always-on nor does it reserve
646 information, see Documentation/driver-api/clk.rst.
648 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
665 [X86-32] pit,hpet,tsc;
672 [X86-64] hpet,tsc
678 architected timer so that code using WFE-based polling
698 clocksource-wdtest.holdoff= [KNL]
699 Set the time in seconds that the clocksource
704 cma=nn[MG]@[start[MG][-end[MG]]]
715 Sets the size of kernel per-numa memory area for
717 per-numa CMA altogether. And If this option is not
719 With per-numa CMA enabled, DMA users on node nid will
744 allocations, by default set to 256K.
746 com20020= [HW,NET] ARCnet - COM20020 chipset
750 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
754 ARCnet - COM90xx chipset (memory-mapped buffers)
762 When set to true, drop data on the 3215 console when
767 This leads to a much faster boot time when a 3270
783 See Documentation/admin-guide/serial-console.rst for more
793 Start an early, polled-mode console on the 8250/16550
796 MMIO inter-register address stride is either 8-bit
797 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
801 the h/w is not re-initialized.
821 "[time stamp] text\n" format (time stamp may not be
825 Switch to syslog format: "<%u>[time stamp] text\n"
828 syscall, or to executing "dmesg -S --raw" or to reading
845 1: enable debugging at boot time
852 disable the cpuidle sub-system
858 disable the cpufreq sub-system
866 [X86] Delay for N microsec between assert and de-assert
878 Run kdump after running panic-notifiers and dumping
891 [KNL, X86-64, ARM64, RISCV, LoongArch] Select a region
894 See Documentation/admin-guide/kdump/kdump.rst for further details.
899 start-[end] where start and end are both
901 Documentation/admin-guide/kdump/kdump.rst for an example.
904 [KNL, X86-64, ARM64, RISCV, LoongArch] range could be
906 Allow kernel to allocate physical memory region from top,
912 [KNL, X86-64, ARM64, RISCV, LoongArch] range under 4G.
918 for 32-bit devices won't run out. Kernel would try to allocate
921 --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
922 --> arm64: 128MiB
923 --> riscv: 128MiB
924 --> loongarch: 128MiB
932 [KNL] Disable crypto self-tests
940 csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
955 See also Documentation/input/devices/joystick-parport.rst
968 [KNL] verbose locking self-tests
971 self-tests.
973 (no extra messages), setting it to -1 (all bits set)
974 will print _a_lot_ more information - normally only
980 [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
999 [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this parameter
1000 enables the feature at boot time. By default, it is
1009 Format: { on, no-mount, off }
1011 no-mount:
1016 get a -EPERM as result when trying to register files
1020 Default value is set in build-time with a kernel configuration.
1032 Documentation/admin-guide/mm/hugetlbpage.rst.
1036 [KNL] Debugging option to set a timeout in seconds for
1040 of 0 will timeout at the end of initcalls. If the time
1046 delayacct [KNL] Enable per-task delay accounting
1063 [HW] Allow controlling fans only if SYS_ADMIN
1064 capability is set.
1085 Set number of hash buckets for dentry cache.
1141 entries for DMA-API debugging code. One entry is
1142 required per DMA-API allocation. Use this if the
1143 DMA-API debugging code disables itself because the
1147 With this option the DMA-API debugging driver
1148 filter feature can be enabled at boot time. Just
1165 Generic built-in EDID data sets are used, if one of
1170 available in Documentation/admin-guide/edid.rst. An EDID
1171 data set will only be used for a particular connector,
1174 set by separating the files with a comma. An EDID
1175 data set with no connector name will be used for
1182 Control how the dt_cpu_ftrs device-tree binding is
1192 what data is available or for reverse-engineering.
1196 Enable debug messages at boot time. See
1197 Documentation/admin-guide/dynamic-debug-howto.rst
1208 determined by stdout-path property in device tree's
1213 Start an early, polled-mode console on a Cadence
1224 Start an early, polled-mode console on the 8250/16550
1226 MMIO inter-register address stride is either 8-bit
1227 (mmio) or 32-bit (mmio32 or mmio32be).
1232 the uart clock frequency; if unspecified, it is set
1237 Start an early, polled-mode console on a pl011 serial
1241 the driver will use only 32-bit accessors to read/write
1250 Start an early, polled-mode console on a meson serial
1256 Start an early, polled-mode console on an msm serial
1262 Start an early, polled-mode console on an msm serial
1268 Start an early, polled-mode console on a serial port
1274 Start an early, polled-mode console on a serial port
1280 Use RISC-V SBI (Supervisor Binary Interface) for early
1298 Start an early, polled-mode console on a lantiq serial
1312 Start an early, polled-mode, output-only console on the
1317 Start an early, polled-mode console on the
1323 Start an early, polled-mode console on a Qualcomm
1331 coherent non-x86 systems that use system memory for
1361 be used at a time.
1417 no_disable_early_pci_dma: Leave the busmaster bit set
1434 attribute is added to range 0x100000000-0x180000000 and
1435 0x10a0000000-0x1120000000.
1439 range 0x240000000-0x43fffffff.
1451 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1457 ekgdboc= [X86,KGDB] Allow early kernel console debugging
1468 elanfreq= [X86-32]
1476 See Documentation/admin-guide/kdump/kdump.rst for details.
1487 The kernel tries to set a reasonable default.
1489 enforcing= [SELINUX] Set initial enforcing status.
1492 0 -- permissive (log only, no denials).
1493 1 -- enforcing (deny and log).
1525 See also Documentation/fault-injection/.
1529 See Documentation/admin-guide/sysctl/net.rst for
1533 See Documentation/admin-guide/blockdev/floppy.rst.
1535 forcepae [X86-32]
1543 [FTRACE] will set and start the specified tracer
1571 ftrace_filter=[function-list]
1573 tracer at boot up. function-list is a comma-separated
1575 time by the set_ftrace_filter file in the debugfs
1578 ftrace_notrace=[function-list]
1580 function-list. This list can be changed at run time
1584 ftrace_graph_filter=[function-list]
1587 function-list is a comma-separated list of functions
1588 that can be changed at run time by the
1591 ftrace_graph_notrace=[function-list]
1593 function-list. This list is a comma-separated list of
1594 functions that can be changed at run time by the
1600 can be changed at run time by the max_graph_depth file
1613 off -- Don't create device links from firmware info.
1614 permissive -- Create device links from firmware info
1617 on -- Create device links from firmware info and use it
1619 rpm -- Like "on", but also use to order runtime PM.
1632 strict -- Default. Continue waiting on consumers to
1634 timeout -- Give up waiting on consumers and call
1644 See also Documentation/input/devices/joystick-parport.rst
1648 gart_fix_e820= [X86-64] disable the fix e820 for K8 GART
1672 gcov_persist= [GCOV] When non-zero (default), profiling data for
1676 debugfs files are removed at module unload time.
1682 gpio-mockup.gpio_mockup_ranges
1685 gpio-mockup.gpio_mockup_named_lines
1717 against bounds-checking flaws in the kernel's
1723 [KNL] Should the hard-lockup detector generate
1729 for 64-bit NUMA, off otherwise.
1732 hcl= [IA-64] SGI's Hardware Graph compatibility layer
1739 corresponding firmware-first mode error processing
1748 (that will set all pages holding image data
1749 during restoration read-only).
1762 hostname= [KNL] Set the hostname (aka UTS nodename).
1766 Using this parameter to set the hostname makes it
1767 possible to ensure the hostname is correctly set before
1770 has been explicitly set, resulting in the calling
1775 hpet= [X86-32,HPET] option to control HPET usage
1779 force: allow force enabled of undocumented chips (ICH4,
1783 hpet_mmap= [X86, HPET_MMAP] Allow userspace to mmap HPET
1784 registers. Default set by CONFIG_HPET_MMAP_DEFAULT.
1792 number of pages to allocate per-node can be specified.
1793 See also Documentation/admin-guide/mm/hugetlbpage.rst.
1804 Documentation/admin-guide/mm/hugetlbpage.rst.
1815 boot-time allocation of gigantic hugepages is skipped.
1843 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1849 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1854 which allow the hypervisor to 'idle' the
1866 (disabled by default, and as a pre-condition
1868 i8042.direct [HW] Put keyboard port into non-translated mode
1882 suspend-to-ram transitions, only during s2r
1892 [HW] Allow deferred probing upon i8042 probe errors
1898 set the brightness of the panel backlight. Normally a
1901 to maximum brightness. If this parameter is set to 0
1903 is set to 1, a brightness value of 0 sets the backlight
1906 -1 -- never invert brightness
1907 0 -- machine default
1908 1 -- force brightness inversion
1910 ia32_emulation= [X86-64]
1912 When true, allows loading 32-bit programs and executing 32-bit
1914 boot time. When false, unconditionally disables IA32 emulation.
1928 idle=nomwait: Disable mwait for CPU C-states
1932 Allow force disabling of Shared Virtual Memory (SVA)
1933 support for the idxd driver. By default it is set to
1938 Allow override of default traffic class configuration
1939 for the device. By default it is set to false (0).
1948 of an ELF file header flag individually set by each
1956 legacy only accept legacy-NaN binaries, if supported
1958 2008 only accept 2008-NaN binaries, if supported
1967 'relaxed' straps the emulator for both legacy-NaN and
1968 2008-NaN, whereas 'strict' enables legacy-NaN only on
1977 Ignore loglevel setting - this will print /all/
1989 Set number of hash buckets for inode cache.
2018 mode bit set by either the effective uid (euid=0) or
2044 Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" |
2045 "ima-sigv2" }
2046 Default: "ima-ng"
2054 Set the minimal file size for using asynchronous hash.
2063 Set hashing buffer size. Default: 4k.
2078 initcall_blacklist= [KNL] Do not execute a comma-separated list of
2079 initcall functions. Useful for debugging built-in
2106 Default set by CONFIG_INIT_ON_ALLOC_DEFAULT_ON.
2110 Default set by CONFIG_INIT_ON_FREE_DEFAULT_ON.
2124 0 -- basic integrity auditing messages. (Default)
2125 1 -- additional integrity auditing messages.
2153 could harm performance of some high-throughput
2162 1 to 9 specify maximum depth of C-state.
2171 algorithms for p-state selection. There are two
2172 P-state selection algorithms provided by
2175 on whether or not the hardware managed P-states
2182 used along with the hardware-managed P-states (HWP)
2186 in favor of acpi-cpufreq. Forcing the intel_pstate driver
2187 instead of acpi-cpufreq may disable platform features, such
2189 P-States information being indicated to OSPM and therefore
2192 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
2205 Allow per-logical-CPU P-State performance control limits using
2208 intremap= [X86-64, Intel-IOMMU]
2213 BIOS x2APIC opt-out request will be ignored
2237 0 - Try to allocate a 32-bit DMA address first, before
2239 1 - Allocate directly from the full usable range,
2241 greater than 32-bit addressing.
2245 0 - Lazy mode.
2251 1 - Strict mode.
2254 unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
2256 legacy driver-specific options takes precedence.
2261 0 - Use IOMMU translation for DMA.
2262 1 - Bypass the IOMMU for DMA.
2263 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2265 io7= [HW] IO7 for Marvel-based Alpha systems
2280 See Documentation/admin-guide/nfs/nfsroot.rst.
2285 irqaffinity= [SMP] Set the default irq affinity mask
2304 Enables support for pseudo-NMIs in the kernel. This
2322 isolcpus= [KNL,SMP,ISOL] Isolate a given set of CPUs from disturbance.
2323 [Deprecated - use cpusets instead]
2324 Format: [flag-list,]<cpu-list>
2350 move in and out of an isolated set anytime.
2355 "number of CPUs in system - 1".
2381 The format of <cpu-list> is described above.
2385 ivrs_ioapic [HW,X86-64]
2386 Provide an override to the IOAPIC-ID<->DEVICE-ID
2390 For example, to map IOAPIC-ID decimal 10 to
2396 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2399 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2403 ivrs_hpet [HW,X86-64]
2404 Provide an override to the HPET-ID<->DEVICE-ID
2408 For example, to map HPET-ID decimal 10 to
2414 * To map HPET-ID decimal 0 to PCI device 00:14.0
2417 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2421 ivrs_acpihid [HW,X86-64]
2422 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2426 For example, to map UART-HID:UID AMD0020:0 to
2432 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2435 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2456 kernelcore= [KNL,X86,IA-64,PPC]
2459 the kernel for non-movable allocations. The requested
2469 subsystem. Note that allocations like PTEs-from-HighMem
2477 for non-movable allocations and remaining memory is used
2488 gdb or control-c on the dbgp connection. When
2489 not using this parameter you use sysrq-g to break into
2494 or a supported polling keyboard driver (non-usb).
2521 Configure the RouterBoard 532 series on-chip
2524 kmemleak= [KNL] Boot-time kmemleak enable/disable
2530 kprobe_event=[probe-list]
2531 [FTRACE] Add kprobe events and enable at boot time.
2532 The probe-list is a semicolon delimited list of probe
2550 CONFIG_KUNIT to be set to be fully enabled. The
2562 execution by eliminating the write-protection faults
2568 disabling eager page splitting to allow huge pages to
2606 [KVM] Controls the time period at which KVM zaps 4KiB pages
2607 back to huge pages. If the value is a non-zero N, KVM will
2612 kvm-amd.nested= [KVM,AMD] Control nested virtualization feature in
2615 kvm-amd.npt= [KVM,AMD] Control KVM's use of Nested Page Tables,
2616 a.k.a. Two-Dimensional Page Tables. Default is 1
2620 kvm-arm.mode=
2625 nvhe: Standard nVHE-based mode, without support for
2628 protected: nVHE-based mode with support for guests whose
2631 nested: VHE-based mode with support for nested
2640 kvm-arm.vgic_v3_group0_trap=
2641 [KVM,ARM] Trap guest accesses to GICv3 group-0
2644 kvm-arm.vgic_v3_group1_trap=
2645 [KVM,ARM] Trap guest accesses to GICv3 group-1
2648 kvm-arm.vgic_v3_common_trap=
2652 kvm-arm.vgic_v4_enable=
2653 [KVM,ARM] Allow use of GICv4 for direct injection of
2664 kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables,
2665 a.k.a. Two-Dimensional Page Tables. Default is 1
2669 kvm-intel.emulate_invalid_guest_state=
2671 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2677 kvm-intel.flexpriority=
2682 kvm-intel.nested=
2686 kvm-intel.unrestricted_guest=
2692 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2693 CVE-2018-3620.
2704 kvm-intel.vpid= [KVM,Intel] Control KVM's use of Virtual Processor
2724 on - enable the interface for the mitigation
2789 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
2795 lapic [X86-32,APIC] Enable the local APIC even if BIOS
2799 value for LAPIC timer one-shot implementation. Default
2819 when set.
2822 libata.force= [LIBATA] Force configurations. The format is a comma-
2834 first fan-out link behind PMP device. It does not
2848 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
2855 * rstonce: only attempt one reset during hot-unplug
2872 * max_trim_128m: Set 128M maximum trim size limit.
2890 * max_sec_128: Set transfer size limit to 128 sectors.
2892 * max_sec_1024: Set or clear transfer size limit to
2895 * max_sec_lba48: Set or clear transfer size limit to
2929 Enable the kernel lockdown feature. If set to
2930 integrity, kernel features that allow userland to
2931 modify the running kernel are disabled. If set to
2932 confidentiality, kernel features that allow userland
2937 Set the time limit in jiffies for a lock
2950 Specify the number of self-propagating call_rcu()
2951 chains to set up. These are used to ensure that
2953 in progress at any given time. Defaults to 0,
2958 occasional long-duration lock hold time. Defaults
2969 Set the number of locking read-acquisition kthreads.
2970 Defaults to being automatically set based on the
2974 Set the number of locking write-acquisition kthreads.
2977 Set time (s) after boot for CPU-hotplug testing.
2980 Set time (s) between CPU-hotplug operations, or
2981 zero to disable CPU-hotplug testing.
2984 Do periodic testing of real-time lock priority
2989 non-real-time spinlocks, due to their disabling
2990 of preemption. Note that non-realtime mutexes
2997 number of boosts per unit time remains roughly
3003 Set task-shuffle interval (jiffies). Shuffling
3004 tasks allows some CPUs to go into dyntick-idle
3008 Set time (s) after boot system shutdown. This
3009 is useful for hands-off automated testing.
3012 Time (s) between statistics printk()s.
3015 Time (s) to stutter testing, for example,
3028 Run the write-side locktorture kthreads at
3029 sched_set_fifo() real-time priority.
3046 7 (KERN_DEBUG) debug-level messages
3056 logo.nologo [FB] Disables display of the built-in Linux logo.
3074 an IEEE 1284-compliant printer is attached; if
3080 time-consuming boot-time autodetection (up to 250 ms per
3101 machvec= [IA-64] Force the use of a particular machine-vector
3107 Example: machtype=lemote-yeeloong-2f-7inch
3109 max_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory greater
3122 (loop.max_loop) unconditionally pre-created at init time. The default
3125 devices can be requested on-demand with the
3126 /dev/loop-control interface.
3128 mce [X86-32] Machine Check Exception
3130 mce=option [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
3133 See Documentation/admin-guide/md.rst.
3140 Control mitigation for the Micro-architectural Data
3155 full - Enable MDS mitigation on vulnerable CPUs
3156 full,nosmt - Enable MDS mitigation and disable
3158 off - Unconditionally disable MDS mitigation
3160 On TAA-affected machines, mds=off can be prevented by
3169 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3171 mem=nn[KMG] [HEXAGON] Set the memory size.
3183 [ARC,MICROBLAZE] - the limit applies only to low memory,
3186 [ARM64] - only limits memory covered by the linear
3194 Note that this only takes effects during boot time since
3199 [ARM,MIPS] - override the memory layout reported by
3206 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3212 [KNL,SH] Allow user to override the default size for
3213 per-device physically contiguous DMA buffers.
3216 [KNL] Set the initial state for the memory hotplug
3218 set according to the
3221 See Documentation/admin-guide/mm/memory-hotplug.rst.
3246 Example: Exclude memory from 0x18690000-0x1869ffff
3260 memmap=<size>%<offset>-<oldtype>+<newtype>
3262 from <oldtype> to <newtype>. If "-<oldtype>" is left
3277 repeatable BIOS-originated corruption always
3299 hotadded memory which will allow to hotadd a
3316 pattern from a given set of patterns. Memtest
3321 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3329 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
3333 s2idle - Suspend-To-Idle
3334 shallow - Power-On Suspend or equivalent (if supported)
3335 deep - Suspend-To-RAM or equivalent (if supported)
3336 See Documentation/admin-guide/pm/sleep-states.rst.
3338 mfgpt_irq= [IA-32] Specify the IRQ to use for the
3339 Multi-Function General Purpose Timers on AMD Geode
3342 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
3354 min_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory below this
3361 0 - The attached screen is the 3.5" TFT
3362 1 - The attached screen is the 7" TFT
3363 2 - The VGA Shield is attached (1024x768)
3367 b - Enable backlight. The TFT backlight pin will be
3371 c - Enable the s3c camera interface.
3372 t - Reserved for enabling touchscreen support. The
3376 https://repo.or.cz/w/linux-2.6/mini2440.git
3380 CPU vulnerabilities. This is a set of curated,
3381 arch-independent options, each of which is an
3382 aggregation of existing arch-specific options.
3405 ssbd=force-off [ARM64]
3418 have other ways of avoiding SMT-based attacks.
3432 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
3453 full - Enable mitigation on vulnerable CPUs
3455 full,nosmt - Enable mitigation and disable SMT on
3458 off - Unconditionally disable mitigation
3471 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3481 [KNL] When set to true, modules will use async probing
3490 [KNL] When CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS is set,
3493 if MODULE_DEBUG_AUTOLOAD_DUPS_TRACE is set, WARN_ON()s
3496 [KNL] When CONFIG_MODULE_SIG is set, this means that
3498 Note that if CONFIG_MODULE_SIG_FORCE is set, that
3501 module_blacklist= [KNL] Do not load a comma-separated list of
3505 [MOUSE] Maximum time between finger touching and
3515 movablecore= [KNL,X86,IA-64,PPC]
3526 movable_node [KNL] Boot-time switch to make hotplugable memory
3533 Format: <name>,<region-number>,<size>,<offset>
3536 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3544 See arch/arm/mach-s3c/mach-jive.c
3552 registers at boot time.
3569 Set to 2 or more if your graphical card needs more.
3573 at a time.
3580 something different and driver-specific.
3585 [NET] Specifies amount of time (in seconds) that
3604 [NFSv4] set the total number of threads that the
3609 [NFS] set the TCP port on which the NFSv4 callback
3620 [NFS] enable 64-bit inode numbers.
3621 If zero, the NFS client will fake up a 32-bit inode
3623 of returning the full 64-bit number.
3624 The default is to return 64-bit inode numbers.
3627 [NFS] set the maximum lifetime for idmapper cache
3646 [NFSv4] When set to the default of '1', this option
3656 To turn off this behaviour, set the value to '0'.
3659 [NFS4] Specify an additional fixed unique ident-
3662 UUID that is generated at system install time.
3671 attempting to recover these locks, then set this
3689 whatever value is the default set by the layout
3690 driver. A non-zero value sets the minimum interval
3694 [NFSv4.2] When set to 1, the server will support
3695 server-to-server copies for which this server is
3699 [NFSv4] When set to the default of '1', the NFSv4
3707 server-to-server copy, knfsd temporarily mounts
3714 See Documentation/admin-guide/nfs/nfsroot.rst.
3716 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3717 See Documentation/admin-guide/nfs/nfsroot.rst.
3720 See Documentation/admin-guide/nfs/nfsroot.rst.
3724 NMI stack-backtrace request.
3733 0 - turn hardlockup detector in nmi_watchdog off
3734 1 - turn hardlockup detector in nmi_watchdog on
3737 watchdog, if CONFIG_BOOTPARAM_HARDLOCKUP_PANIC is set)
3746 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
3750 no4lvl [RISCV] Disable 4-level and 5-level paging modes. Forces
3751 kernel to use 3-level paging instead.
3753 no5lvl [X86-64,RISCV] Disable 5-level paging mode. Forces
3754 kernel to use 4-level paging instead.
3757 caches in the slab allocator. Saves per-node memory,
3790 nodsp [SH] Disable hardware DSP at boot time.
3794 no_entry_flush [PPC] Don't flush the L1-D cache when entering the kernel.
3796 noexec [IA-64]
3798 noexec32 [X86-64]
3799 This affects only 32-bit executables.
3800 noexec32=on: enable non-executable mappings (default)
3802 noexec32=off: disable non-executable mappings
3809 nofpu [MIPS,SH] Disable hardware FPU at boot time.
3813 nofxsr [BUGS=X86-32] Disables x86 floating point extended
3815 legacy floating-point registers on task switch.
3817 nohalt [IA-64] Tells the kernel not to use the power saving
3819 power-consumption. On the positive side, it reduces
3820 interrupt wake-up latency, which may improve performance
3822 real-time systems.
3832 compared. However, if this command-line option is
3859 In kernels built with CONFIG_NO_HZ_FULL=y, set
3873 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
3875 [Deprecated - use intremap=off]
3877 nointroute [IA-64]
3883 noirqdebug [X86-32] Disables the code which attempts to detect and
3888 nojitter [IA-64] Disables jitter checking for ITC timers.
3891 When CONFIG_RANDOMIZE_BASE is set, this disables
3895 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
3898 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
3900 nolapic [X86-32,APIC] Do not enable or use the local APIC.
3902 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
3904 nomca [IA-64] Disable machine check abort handling
3906 nomce [X86-32] Disable Machine Check Exception
3908 nomfgpt [X86-32] Disable Multi-Function General Purpose
3914 not load if they could possibly displace the pre-
3917 perform display-mode changes or accelerated rendering.
3930 nopcid [X86-64] Disable the PCID cpu feature.
3935 nopti [X86-64]
3945 which allow the hypervisor to 'idle' the guest on lock
3951 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
3957 nosbagart [IA-64]
3959 no-scroll [VGA] Disables scrollback.
3960 This is required for the Braillex ib80-piezo Braille
3963 nosgx [X86-64,SGX] Disables Intel SGX kernel support.
3983 nosoftlockup [KNL] Disable the soft-lockup detector.
3988 nospectre_bhb [ARM64] Disable all mitigations for Spectre-BHB (branch
3989 history injection) vulnerability. System may allow data leaks
3998 vulnerability. System may allow data leaks with this
4001 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV] Disable
4002 paravirtualized steal time accounting. steal time is
4011 [PPC] Don't flush the L1-D cache after accessing user data.
4022 is set.
4024 no-vmw-sched-clock
4029 soft-lockup and NMI watchdog (hard-lockup).
4033 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
4036 LEGACY_XAPIC_DISABLED bit set in the
4041 enabling legacy floating-point and sse state.
4067 nptcg= [IA-64] Override max number of concurrent global TLB
4076 n. So during boot up some boot time memory for per-cpu
4077 variables need be pre-allocated for later physical cpu
4083 set up a single NUMA node spanning all memory.
4091 This can be set from sysctl after boot.
4092 See Documentation/admin-guide/sysctl/vm.rst for details.
4095 See Documentation/core-api/debugging-via-ohci1394.rst for more
4102 waiting for the ACK, so if this is set too high
4110 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4114 boundary - index of last SLC block on Flex-OneNAND.
4116 lock - Configure if Flex-OneNAND boundary should be locked.
4130 running on a platform with a direct-mapped memory-side
4136 page_owner= [KNL] Boot-time page_owner enabling option.
4142 page_poison= [KNL] Boot-time parameter changing the state of
4162 Hexadecimal bitmask representing the set of TAINT flags
4164 called with any of the flags in this set.
4168 bitmask set on panic_on_taint.
4169 See Documentation/admin-guide/tainted-kernels.rst for
4221 Set to non-zero to probe primary and secondary ISA
4227 Set to non-zero if a chip is present that snoops speed
4232 Set to 1, 2, or 3 for HT 6560A on the primary channel,
4238 Set to 1, 2, or 3 for HT 6560B on the primary channel,
4244 IORDY enable mask. Set individual bits to allow IORDY
4256 Set to 1, 2, or 3 for Opti 82c611A on the primary
4262 Set to 1, 2, or 3 for Opti 82c465MV on the primary
4268 PIO mode mask for autospeed devices. Set individual
4269 bits to allow the use of the respective PIO modes.
4275 Set to non-zero to probe tertiary and further ISA
4291 Set to non-zero to probe QDI controllers. By default
4292 set to 1 if CONFIG_PATA_QDI_MODULE, 0 otherwise.
4296 Set to non-zero to probe Winbond controllers. Use
4299 By default set to 1 if CONFIG_PATA_WINBOND_VLB_MODULE,
4304 Supported PIO mode mask. Set individual bits to allow
4319 or a set of devices (<pci_dev>). These are
4343 bios [X86-32] force use of PCI BIOS, don't access
4345 has a non-standard PCI host bridge.
4346 nobios [X86-32] disallow use of PCI BIOS, only direct
4352 data in IO port 0xCFC, both 32-bit).
4354 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4355 the function, IO port 0xCFA, also 8-bit, sets
4357 through ports 0xC000-0xCFFF).
4364 root domains (aka PCI segments, in ACPI-speak).
4372 disable the use of MSI interrupts system-wide.
4377 primary IO-APIC for bridges that cannot disable
4384 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4401 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
4408 F0000h-100000h range.
4413 assign-busses [X86] Always assign all PCI bus
4434 <linux-pci@vger.kernel.org>.
4438 a bug to <linux-pci@vger.kernel.org>.
4450 bfsort Sort PCI devices into breadth-first order.
4453 nobfsort Don't sort PCI devices into breadth-first order.
4455 tuning and use the BIOS-configured MPS defaults.
4456 pcie_bus_safe Set every device's MPS to the largest value
4458 pcie_bus_perf Set device MPS to the largest allowable MPS
4459 based on its parent bus. Also set MRRS (Max
4463 pcie_bus_peer2peer Set every device's MPS to 128B, which
4465 configuration allows peer-to-peer DMA between
4468 that hot-added devices will work.
4483 A PCI-PCI bridge can be specified if resource
4489 for 4096-byte alignment.
4491 end-to-end CRC checking). Only effective if
4522 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4529 can resize a BAR to allow access to all VRAM.
4538 allow P2P traffic between devices through
4558 dpc-native Use native PCIe service for DPC only. May
4575 Keep all power-domains already enabled by bootloader on,
4581 boot time.
4592 pirq= [SMP,APIC] Manual mp-table setup
4593 See Documentation/arch/x86/i386/IO-APIC.rst.
4597 See also Documentation/admin-guide/parport.rst.
4607 cleared). If a number is given, then MMCR1 is set to
4616 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4625 { on | off | curr | res | no-curr | no-res }
4665 none - Limited to cond_resched() calls
4666 voluntary - Limited to cond_resched() and might_sleep() calls
4667 full - Any section that isn't explicitly preempt disabled
4670 print-fatal-signals=
4676 coredump - etc.
4679 you might want to try "ulimit -i unlimited".
4691 or lockdep-detected issues (only if lock debug is on).
4700 on - unlimited logging to /dev/kmsg from userspace
4701 off - logging to /dev/kmsg disabled
4702 ratelimit - ratelimit the logging
4705 printk.time= Show timing data prefixed to each printk message line
4709 Limit processor to maximum C-state
4713 Ignore the _CST method to determine C-states,
4720 Param: "schedule" - profile schedule points.
4721 Param: "sleep" - profile D-state sleeping (millisecs).
4723 Param: "kvm" - profile VM exits.
4724 Param: <number> - step/bucket size as a power of 2 for
4725 statistical time based profiling.
4740 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
4746 [HW,MOUSE] Set desired mouse resolution, in dpi.
4753 pti= [X86-64] Control Page Table Isolation of user and
4758 on - unconditionally enable
4759 off - unconditionally disable
4760 auto - kernel detects whether your CPU model is
4766 [KNL] Number of legacy pty's. Overwrites compiled-in
4778 See Documentation/admin-guide/md.rst.
4781 See Documentation/admin-guide/blockdev/ramdisk.rst.
4800 cross-syscall address exposures. This is only
4806 ras=option[,option,...] [KNL] RAS-specific options
4812 rcu_nocbs[=cpu-list]
4817 enable the no-callback CPU mode, which prevents
4822 "p" for RCU-preempt, "s" for RCU-sched, and "g"
4826 and real-time workloads. It can also improve
4830 list of CPUs is set to no-callback mode from boot.
4833 arguments are omitted, no CPU will be set to
4834 no-callback mode from boot but the mode may be
4845 This improves the real-time response for the
4852 Set maximum number of finished RCU callbacks to
4859 If triggered before the RCU grace-period machinery
4868 Set the number of jiffies to delay each step of
4869 RCU grace-period cleanup.
4872 Set the number of jiffies to delay each step of
4873 RCU grace-period initialization.
4876 Set the number of jiffies to delay each step of
4877 RCU grace-period pre-initialization, that is,
4878 the propagation of recent CPU-hotplug changes up
4882 Set delay from grace-period initialization to
4888 Set delay between subsequent attempts to force
4893 Set required age in jiffies for a
4895 soliciting quiescent-state help from
4902 rcutree.jiffies_to_sched_qs. Any attempt to set
4907 Set the SCHED_FIFO priority of the RCU per-CPU
4910 and for the RCU grace-period kthreads (rcu_bh,
4912 set, valid values are 1-99 and the default is 1
4913 (the least-favored priority). Otherwise, when
4914 RCU_BOOST is not set, valid values are 0-99 and
4915 the default is zero (non-realtime operation).
4916 When RCU_NOCB_CPU is set, also adjust the
4920 On callback-offloaded (rcu_nocbs) CPUs,
4923 use of the ->nocb_bypass list. However, in the
4924 common non-flooded case, RCU queues directly to
4925 the main ->cblist in order to avoid the extra
4926 overhead of the ->nocb_bypass list and its lock.
4928 a single jiffy, RCU pre-queues the callbacks into
4929 the ->nocb_bypass queue. The definition of "too
4933 Set threshold of queued RCU callbacks beyond which
4937 Set threshold of queued RCU callbacks below which
4938 batch limiting is re-enabled.
4941 Set threshold of queued RCU callbacks beyond which
4942 RCU's force-quiescent-state scan will aggressively
4945 Set to less than zero to make this be set based
4946 on rcutree.qhimark at boot time and to zero to
4950 Set the page-cache refill delay (in milliseconds)
4951 in response to low-memory conditions. The range
4955 Set the shift-right count to use to compute
4956 the callback-invocation batch limit bl from
4961 order to allow the CPU to do other work.
4963 Please note that this callback-invocation batch
4964 limit applies only to non-offloaded callback
4973 cache-to-cache transfer latencies.
4979 and for NUMA systems with large remote-access
4992 Set the number of NOCB callback kthreads in
4995 the wakeup overhead on the global grace-period
4997 each group's NOCB grace-period kthread.
5000 Cause the grace-period kthread to get an extra
5002 it should at force-quiescent-state time.
5007 Limit the time spend invoking a batch of RCU
5015 this specifies an rcu_read_unlock()-time delay
5019 of RCU-protected pointers after the relevant
5028 If set to zero, move all RCU_SOFTIRQ processing to
5029 per-CPU rcuc kthreads. Defaults to a non-zero
5039 grace-period primitives such as call_rcu().
5045 corresponding flavor of rcu_barrier() to allow
5050 grace-period primitives.
5053 Set test-start holdoff period. The purpose of
5068 Set to measure performance of kfree_rcu() flooding.
5071 Test the double-argument variant of kfree_rcu().
5073 rcuscale.kfree_rcu_test_single, both the single-
5074 and double-argument variants are tested.
5077 Test the single-argument variant of kfree_rcu().
5079 rcuscale.kfree_rcu_test_double, both the single-
5080 and double-argument variants are tested.
5093 Set the minimum test run time in seconds. This
5094 does not affect the data-collection interval,
5099 Set number of RCU readers. The value -1 selects
5101 "n" less than -1 selects N-n+1, where N is again
5102 the number of CPUs. For example, -2 selects N
5103 (the number of CPUs), -3 selects N+1, and so on.
5104 A value of "n" less than or equal to -N selects
5108 Set number of RCU writers. The values operate
5117 complete. This is useful for hands-off automated
5124 Write-side holdoff between grace periods,
5129 Additional write-side holdoff between grace
5134 Set duration of force_quiescent_state bursts
5138 Set holdoff time within force_quiescent_state bursts
5142 Set wait time between force_quiescent_state bursts
5147 for RCU grace-period forward-progress testing
5154 Specify the fraction of a CPU-stall-warning
5155 period to do tight-loop forward-progress testing.
5159 forward-progress tests.
5163 need_resched() during tight-loop forward-progress
5167 Use conditional/asynchronous update-side
5171 Use expedited update-side primitives, if available.
5174 Use normal (non-expedited) asynchronous
5175 update-side primitives, if available.
5178 Use normal (non-expedited) synchronous
5179 update-side primitives, if available. If all
5183 they are all non-zero.
5191 Leak an RCU-protected pointer out of the reader.
5198 Set callbacks/threads for rcu_barrier() testing.
5201 Set number of concurrent RCU writers. These just
5206 Set number of RCU callback-offload togglers.
5210 Set the delay in milliseconds between successive
5211 callback-offload toggling attempts.
5214 Set number of RCU readers. The value -1 selects
5215 N-1, where N is the number of CPUs. A value
5216 "n" less than -1 selects N-n-2, where N is again
5217 the number of CPUs. For example, -2 selects N
5218 (the number of CPUs), -3 selects N+1, and so on.
5221 Enable debug-object double-call_rcu() testing.
5224 Set time (s) after boot for CPU-hotplug testing.
5227 Set time (jiffies) between CPU-hotplug operations,
5228 or zero to disable CPU-hotplug testing.
5231 Set the number of read-then-exit kthreads used
5233 task-exit processing.
5236 The number of times in a given read-then-exit
5237 episode that a set of read-then-exit kthreads
5242 read-then-exit testing episodes.
5245 Set task-shuffle interval (s). Shuffling tasks
5246 allows some CPUs to go into dyntick-idle mode
5250 Set time (s) after boot system shutdown. This
5251 is useful for hands-off automated testing.
5258 Sleep while stalling if set. This will result
5260 any other stall-related activity. Note that
5266 in scheduling-while-atomic splats.
5272 Time to wait (s) after boot before inducing stall.
5275 Disable interrupts while stalling if set.
5279 grace-period kthread to test RCU CPU stall
5285 Time (s) between statistics printk()s.
5288 Time (s) to stutter testing, for example, specifying
5305 Test RCU's dyntick-idle handling. See also the
5330 during early boot, that is, during the time
5334 Set timeout for RCU CPU stall warning messages.
5339 Set timeout for expedited RCU CPU stall warning
5360 Use expedited grace-period primitives, for
5364 real-time latency, and degrade energy efficiency.
5368 Use only normal grace-period primitives,
5371 real-time latency, CPU utilization, and
5373 increased grace-period latency. This parameter
5380 only normal grace-period primitives. No effect
5386 post-boot attempt at an expedited RCU grace
5387 period to instead use normal non-expedited
5388 grace-period processing.
5391 Set the maximum number of callbacks present
5396 set to the default value of -1.
5399 Set the minimum number of callback-queuing-time
5400 lock-contention events per jiffy required to
5401 cause the RCU Tasks flavors to switch to per-CPU
5403 when rcupdate.rcu_task_enqueue_lim is set to
5404 the default value of -1.
5407 Set the number of callback queues to use for the
5409 of -1 allows this to be automatically (and
5414 Set time in jiffies during which RCU tasks will
5417 number avoids disturbing real-time workloads,
5422 cancel laziness on that CPU. Use -1 to disable
5428 Set initial timeout in jiffies for RCU task stall
5432 only printed prior to the stall-warning message
5439 Multiplier for time interval between successive
5450 Set timeout in jiffies for RCU task stall
5457 Set timeout in milliseconds RCU Tasks asynchronous
5464 Set timeout in milliseconds RCU Tasks
5472 Set timeout in milliseconds RCU Tasks
5488 force - Override the decision by the kernel to hide the
5508 (prefix with 'panic_' to set mode for panic
5516 Set test-start holdoff period. The purpose of
5528 Set the number of loops over the synchronization
5531 but the default has already reduced the per-pass
5536 Set number of readers. The default value of -1
5541 Set number of runs, each of which is dumped onto
5545 Set the read-side critical-section duration,
5549 Specify the read-protection implementation to test.
5574 [KNL, SMP] Set scheduler's default relax_domain_level.
5575 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
5583 reservetop= [X86-32]
5600 See Documentation/power/swsusp-and-swap-files.rst
5616 AMD-based UNRET and IBPB mitigations alone do not stop
5618 sibling threads. For that reason, STIBP is used on pro-
5622 off - no mitigation
5623 auto - automatically select a migitation
5624 auto,nosmt - automatically select a mitigation,
5628 ibpb - On AMD, mitigate short speculation
5633 ibpb,nosmt - Like "ibpb" above but will disable SMT
5637 unret - Force enable untrained return thunks,
5638 only effective on AMD f15h-f17h based
5640 unret,nosmt - Like unret, but will disable SMT when STIBP
5645 time according to the CPU.
5662 Set number of hash buckets for route cache
5675 ro [KNL] Mount root device read-only on boot
5678 on Mark read-only kernel memory as read-only (default).
5679 off Leave read-only kernel memory writable for debugging.
5680 full Mark read-only kernel memory and aliases as read-only
5686 debug-uart get routed to the D+ and D- pins of the usb
5692 block/early-lookup.c for details.
5700 rootflags= [KNL] Set root filesystem mount option string
5702 rootfstype= [KNL] Set root filesystem type
5708 rootwait= [KNL] Maximum time (in seconds) to wait for root device
5717 rw [KNL] Mount root device read-write on boot
5722 Set s390 IOTLB flushing mode
5752 [KNL, SMP] Set a decay shift for scheduler thermal
5770 to 10 seconds for built-in smp_call_function()
5777 that requesting even small non-zero numbers of
5784 The default of -1 specifies a number of kthreads
5789 test before initiating CPU-hotplug operations.
5793 CPU-hotplug operations. Specifying zero (which
5794 is the default) disables CPU-hotplug operations.
5800 Non-zero values are useful for automated tests.
5809 to the set of CPUs under test.
5823 "wait" parameter. A value of -1 selects the
5824 default if all other weights are -1. However,
5826 value of -1 will instead select a weight of zero.
5831 non-zero "wait" parameter. See weight_single.
5844 non-zero "wait" parameter. See weight_single
5856 non-zero "wait" parameter. See weight_single
5861 contention on all systems with CONFIG_MAXSMP set.
5863 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
5864 1 -- enable.
5872 selinux= [SELINUX] Disable or enable SELinux at boot time.
5875 0 -- disable.
5876 1 -- enable.
5879 serialnumber [BUGS=X86-32]
5881 sev=option[,option...] [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
5889 to set it to "all" by meaning -- no limit here.
5895 simeth= [IA-64]
5962 Specify the period of time in milliseconds
5967 of time. Defaults to 5,000 milliseconds, and
5970 using the csdlock_debug- kernel parameter.
5975 system. By default, let CSD-lock acquisition
5977 for this value provides a 5-minute timeout.
5979 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
5980 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
5981 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
5982 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
5983 smsc-ircc2.ircc_irq= [HW] IRQ line
5984 smsc-ircc2.ircc_dma= [HW] DMA channel
5985 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
5990 smt= [KNL,MIPS,S390] Set the maximum number of threads (logical
5995 Default: -1 (no limit)
5998 [KNL] Should the soft-lockup detector generate panics.
6001 A value of 1 instructs the soft-lockup detector
6002 to panic the machine when a soft-lockup occurs. It is
6005 respective build-time switch to that functionality.
6008 [KNL] Should the soft-lockup detector generate
6013 See Documentation/admin-guide/laptops/sonypi.rst
6020 on - unconditionally enable, implies
6022 off - unconditionally disable, implies
6024 auto - kernel detects whether your CPU model is
6028 mitigation method at run time according to the
6041 retpoline - replace indirect branches
6042 retpoline,generic - Retpolines
6043 retpoline,lfence - LFENCE; indirect branch
6044 retpoline,amd - alias for retpoline,lfence
6045 eibrs - Enhanced/Auto IBRS
6046 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
6047 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
6048 ibrs - use IBRS to protect kernel
6058 on - Unconditionally enable mitigations. Is
6061 off - Unconditionally disable mitigations. Is
6064 prctl - Indirect branch speculation is enabled,
6070 - Like "prctl" above, but only STIBP is
6076 - Same as "prctl" above, but all seccomp
6081 - Like "seccomp" above, but only STIBP is
6086 auto - Kernel selects the mitigation depending on
6097 off - Disable mitigation
6098 microcode - Enable microcode mitigation only
6099 safe-ret - Enable sw-only safe RET mitigation (default)
6100 ibpb - Enable mitigation by issuing IBPB on
6102 ibpb-vmexit - Issue IBPB only on VMEXIT
6103 (cloud-specific mitigation)
6128 on - Unconditionally disable Speculative Store Bypass
6129 off - Unconditionally enable Speculative Store Bypass
6130 auto - Kernel detects whether the CPU model contains an
6136 prctl - Control Speculative Store Bypass per thread
6140 seccomp - Same as "prctl" above, but all seccomp threads
6148 on,auto - On Power8 and Power9 insert a store-forwarding
6152 off - No action.
6171 off - not enabled
6173 warn - the kernel will emit rate-limited warnings
6181 fatal - the kernel will send SIGBUS to applications
6186 ratelimit:N -
6187 Set system wide rate limit to N bus locks
6206 Certain CPUs are vulnerable to an MDS-like
6226 This kernel-boot parameter defaults to 128,
6227 but takes effect only when the low-order four
6237 1: At init_srcu_struct() time.
6239 3: Decide at boot time (default).
6244 instead of the compile-time CONFIG_NR_CPUS.
6248 grace-period sequence counter wrap for the
6249 srcu_data structure's ->srcu_gp_seq_needed field.
6250 The greater the number of bits set in this kernel
6260 expediting. Set to zero to disable automatic
6264 Specifies the number of no-delay instances
6271 Specifies the per-grace-period phase, number of
6272 non-sleeping polls of readers. Beyond this limit,
6278 Specifies number of microseconds of non-sleeping
6279 delay between each non-sleeping poll of readers.
6282 Specifies the number of update-side contention
6287 set for contention-based conversions to occur.
6297 force-on: Unconditionally enable mitigation for
6299 force-off: Unconditionally disable mitigation for
6303 to allow userspace to register its
6316 consumed by the stack hash table. By default this is set
6322 stacktrace_filter=[function-list]
6324 will trace at boot up. function-list is a comma-separated
6326 time by the stack_trace_filter file in the debugfs
6332 Set the STI (builtin display/keyboard on the HP-PARISC
6334 as the initial boot-console.
6371 using these two parameters to set the minimum and
6394 to global on non-NUMA machines)
6401 server. Increasing these values may allow you to
6410 is set. Default value is 5.
6417 swiotlb= [ARM,IA-64,PPC,MIPS,X86]
6419 <int> -- Number of I/O TLB slabs
6420 <int> -- Second integer after comma. Number of swiotlb
6423 force -- force using of bounce buffers even if they
6425 noforce -- Never use bounce buffers (for debugging)
6430 Set a sysctl parameter, right before loading the init
6435 later by a loaded module cannot be set this way.
6440 Ignore sysrq setting - this boot parameter will
6445 Set the number of tcp_metrics_hash slots.
6448 cache size. See Documentation/networking/ip-sysctl.rst
6455 Specify "mem" (for Suspend-to-RAM) or "standby" (for
6460 wakeup-capable RTC alarm.
6463 Set number of hash buckets for TCP connection
6466 -1: disable all active trip points in all thermal zones
6470 -1: disable all critical trip points in all thermal zones
6477 -1: disable all passive trip points
6483 <deci-seconds>: poll all this frequency
6505 Prevent the CPU-hotplug component of torturing
6509 Dump the ftrace buffer at torture-test shutdown,
6513 with rotating-rust storage.
6518 disables verbose-printk() sleeping.
6521 Duration of each verbose-printk() sleep in jiffies.
6527 Specify that at suspend time, the tpm driver
6536 for the FIFO interface. By default it is set to false
6539 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
6564 When tp_printk (above) is set, it can cause a lot of noise
6570 to console at the late_initcall_sync() time frame.
6573 [FTRACE] will set tracing buffer size on each cpu.
6575 trace_clock= [FTRACE] Set the clock used for tracing events
6577 local - Use the per CPU time stamp counter
6581 global - Event time stamps are synchronize across
6584 counter - Simple counting of events (1, 2, ..)
6588 uptime - Use jiffies as the time stamp.
6589 perf - Use the same clock that perf uses.
6590 mono - Use ktime_get_mono_fast_ns() for time stamps.
6591 mono_raw - Use ktime_get_raw_fast_ns() for time
6593 boot - Use ktime_get_boot_fast_ns() for time stamps.
6597 trace_event=[event-list]
6598 [FTRACE] Set and start specified trace events in order
6599 to facilitate early boot debugging. The event-list is a
6600 comma-separated list of trace events to enable. See
6603 trace_instance=[instance-info]
6609 Events can be enabled at the time the instance is created
6623 trace_options=[option-list]
6625 The option-list is a comma delimited list of options
6639 trace_trigger=[trigger-list]
6641 Set a trigger on top of a specific event, with an optional
6668 This option can also be set at run time via the sysctl
6676 See Documentation/admin-guide/mm/transhuge.rst
6684 - "tpm"
6685 - "tee"
6686 - "caam"
6696 - "kernel"
6697 - the same value as trusted.source: "tpm" or "tee"
6698 - "default"
6707 high-resolution timer mode on older hardware, and in
6710 Used to run time disable IRQ_TIME_ACCOUNTING on any
6743 on - Enable TSX on the system. Although there are
6746 several previous speculation-related CVEs, and
6750 off - Disable TSX on the system. (Note that this
6758 auto - Disable TSX if X86_BUG_TAA is present,
6763 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
6769 Similar to Micro-architectural Data Sampling (MDS)
6784 full - Enable TAA mitigation on vulnerable CPUs
6787 full,nosmt - Enable TAA mitigation and disable SMT on
6790 vulnerable to cross-thread TAA attacks.
6791 off - Unconditionally disable TAA mitigation
6793 On MDS-affected machines, tsx_async_abort=off can be
6805 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
6811 See also Documentation/input/devices/joystick-parport.rst
6813 udbg-immortal [PPC] When debugging early kernel crashes that
6819 Set number of hash buckets for UDP/UDP-Lite connections
6821 uhci-hcd.ignore_oc=
6823 Some badly-designed motherboards generate lots of
6825 anything. Set this parameter to avoid log spamming.
6832 unwind_debug [X86-64]
6840 (default -1 = authorized (same as 1),
6845 [USB] The autosuspend time delay (in seconds) used
6846 for newly-detected USB devices (default 2). This
6847 is the time required before an idle device will be
6848 autosuspended. Devices for which the delay is set
6852 [USB] Set to log all usbfs traffic (default 0 = off).
6859 [USB] Set to cycle leds on hubs (default 0 = off).
6874 [USB] Specifies timeout for the initial 64-byte
6881 [USB] A list of quirk entries to augment the built-in
6884 VendorID:ProductID:Flags. The IDs are 4-digit hex
6885 numbers and Flags is a set of letters. Each letter
6886 will change the built-in quirk; setting it if it is
6887 clear and clearing it if it is set. The letters have
6891 a 255-byte read);
6895 Set-Interface requests);
6914 (bInterval-1).
6952 usb-storage.delay_use=
6956 usb-storage.quirks=
6958 override the built-in unusual_devs list. List
6961 and Product ID values (4-digit hex numbers) and
6962 Flags is a set of characters, each corresponding
6963 to a common usb-storage quirk flag as follows:
6977 240 sectors at a time, uas only);
6989 than 64 sectors = 32 KB at a time,
7001 t = NO_ATA_1X (don't allow ATA(12) and ATA(16)
7005 medium is write-protected).
7014 1 - undefined instruction events
7015 2 - system calls
7016 4 - invalid data aborts
7017 8 - SIGSEGV faults
7018 16 - SIGBUS faults
7034 vdso32= [X86] Control the 32-bit vDSO
7035 vdso32=1: enable 32-bit VDSO
7036 vdso32=0 or vdso32=2: disable 32-bit VDSO
7039 details. If CONFIG_COMPAT_VDSO is set, the default is
7046 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
7048 vector= [IA-64,SMP]
7056 If set to 1, on receiving an ACPI notify event
7059 the allocated input device. If set to 0, video driver
7080 vga= [BOOT,X86-32] Select a particular video mode
7082 Documentation/admin-guide/svga.rst.
7091 interface is meant to allow for selectively
7096 P Enable page structure init time poisoning
7097 - Disable all of the above options
7118 vsyscall= [X86-64]
7121 code). Most statically-linked binaries and older
7145 see VGA-softcursor.txt. Default: 2 = underline.
7150 This is a 16-member array composed of values
7151 ranging from 0-255.
7156 This is a 16-member array composed of values
7157 ranging from 0-255.
7162 This is a 16-member array composed of values
7163 ranging from 0-255.
7168 Set system-wide default UTF-8 mode for all tty's.
7169 Default is 1, i.e. UTF-8 mode is enabled for all
7174 Format=<-1|0|1>
7175 Set system-wide default for whether a cursor
7176 is shown on new VTs. Default is -1,
7181 vt.italic= [VT] Default color for italic text; 0-15.
7184 vt.underline= [VT] Default color for underlined text; 0-15.
7188 see Documentation/watchdog/watchdog-parameters.rst
7189 or other driver-specific files in the
7194 Set the hard lockup detector stall duration
7196 threshold is set to twice the value. A value of 0
7203 Format: <cpu-list>
7217 Per-cpu work items which run for longer than this
7220 them from noticeably delaying other per-cpu work
7223 If CONFIG_WQ_CPU_INTENSIVE_REPORT is set, the kernel
7229 Per-cpu workqueues are generally preferred because
7231 locality; unfortunately, per-cpu workqueues tend to
7234 Enabling this makes the per-cpu workqueues which
7248 Documentation/core-api/workqueue.rst.
7261 forces round-robin CPU selection to flush out
7269 on - Enable writecombine, use WUC for ioremap_wc()
7270 off - Disable writecombine, use SUC for ioremap_wc()
7272 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
7276 xen_512gb_limit [KNL,X86-64,XEN]
7286 ide-disks -- unplug primary master IDE devices
7287 aux-ide-disks -- unplug non-primary-master IDE devices
7288 nics -- unplug network devices
7289 all -- unplug all emulated devices (NICs and IDE disks)
7290 unnecessary -- unplugging emulated devices is
7293 never -- do not unplug even if version check succeeds
7301 Select whether to always use non-faulting (safe) MSR
7326 xen_timer_slop= [X86-64,XEN]
7327 Set the timer slop (in nanoseconds) for the virtual Xen
7334 The time (in seconds) to wait before giving up to boot
7345 After which time (jiffies) the event handling loop
7351 preferred over the 2-level event handling, as it is
7368 xive.store-eoi=off [PPC]
7374 xhci-hcd.quirks [USB,KNL]