Lines Matching +full:i2c +full:- +full:alias +full:- +full:pool
5 force -- enable ACPI if default was off
6 on -- enable ACPI but allow fallback to DT [arm64,riscv64]
7 off -- disable ACPI if default was on
8 noirq -- do not use ACPI for IRQ routing
9 strict -- Be less tolerant of platforms that are not
11 rsdt -- prefer RSDT over (default) XSDT
12 copy_dsdt -- copy DSDT to memory
26 If set to vendor, prefer vendor-specific driver
58 Documentation/firmware-guide/acpi/debug.rst for more information about
116 Format: <byte> or <bitmap-list>
119 Disable auto-serialization of AML methods
122 auto-serialization feature.
140 Ignore the ACPI-based watchdog interface (WDAT) and let
161 acpi_osi=! # disable all built-in OS vendor
163 acpi_osi=!! # enable all built-in OS vendor
225 For broken nForce2 BIOS resulting in XT-PIC timer.
234 as soon as the kernel's real-mode entry point is called.
272 See Documentation/sound/alsa-configuration.rst
279 align_va_addr= [X86-64]
284 CPU-intensive style benchmark, and it can vary highly in
287 32: only for 32-bit processes
288 64: only for 64-bit processes
289 on: enable for both 32- and 64-bit processes
290 off: disable for both 32- and 64-bit processes
300 Allow execve() of 32-bit applications and setting of the
302 subset of the CPUs support 32-bit EL0. When this
303 parameter is present, the set of CPUs supporting 32-bit
305 and hot-unplug operations may be restricted.
307 See Documentation/arch/arm64/asymmetric-32bit.rst for more
310 amd_iommu= [HW,X86-64]
313 fullflush - Deprecated, equivalent to iommu.strict=1
314 off - do not initialize any AMD IOMMU found in
316 force_isolation - Force device isolation for all
321 force_enable - Force enable the IOMMU on platforms known
324 pgtbl_v1 - Use v1 page table for DMA-API (Default).
325 pgtbl_v2 - Use v2 page table for DMA-API.
326 irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
328 amd_iommu_dump= [HW,X86-64]
334 amd_iommu_intr= [HW,X86-64]
337 legacy - Use legacy interrupt remapping mode.
338 vapic - Use virtual APIC mode, which allows IOMMU
340 This mode requires kvm-amd.avic=1.
377 Power management functions (SPARCstation-4/5 + deriv.)
379 Disable APC CPU standby support. SPARCstation-Fox does
380 not play well with APC CPU idle - disable it if you have
387 when initialising the APIC and IO-APIC components.
388 For X86-32, this can also be used to specify an APIC
411 0 -- disable.
412 1 -- enable.
415 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
457 audit= [KNL] Enable the audit sub-system
459 0 | off - kernel audit is disabled and can not be
461 unset - kernel audit is initialized but disabled and
463 1 | on - kernel audit is initialized and partially
476 0 - Disable the BAU.
477 1 - Enable the BAU.
478 unset - Disable the BAU.
505 See Documentation/block/cmdline-partition.rst
518 See Documentation/admin-guide/bootconfig.rst
523 bttv.pll= See Documentation/admin-guide/media/bttv.rst
532 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
551 inclusive. See arch/mips/include/asm/pgtable-bits.h
561 - foo isn't auto-mounted if you mount all cgroups in
563 - foo isn't visible as an individually mountable
565 - if foo is an optional feature then the feature is
571 Specifying "pressure" disables per-cgroup pressure
585 nosocket -- Disable socket memory accounting.
586 nokmem -- Disable kernel memory accounting.
587 nobpf -- Disable BPF memory accounting.
592 0 -- check protection applied by kernel (includes
594 1 -- check protection requested by application.
606 numbers X. Note the Linux-specific bits are not necessarily
607 stable over kernel options, but the vendor-specific
627 force such clocks to be always-on nor does it reserve
631 information, see Documentation/driver-api/clk.rst.
633 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
650 [X86-32] pit,hpet,tsc;
657 [X86-64] hpet,tsc
663 architected timer so that code using WFE-based polling
677 clocksource-wdtest.holdoff= [KNL]
683 cma=nn[MG]@[start[MG][-end[MG]]]
694 Sets the size of kernel per-numa memory area for
696 per-numa CMA altogether. And If this option is not
698 With per-numa CMA enabled, DMA users on node nid will
722 Sets the size of memory pool for coherent, atomic dma
725 com20020= [HW,NET] ARCnet - COM20020 chipset
729 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
733 ARCnet - COM90xx chipset (memory-mapped buffers)
762 See Documentation/admin-guide/serial-console.rst for more
772 Start an early, polled-mode console on the 8250/16550
775 MMIO inter-register address stride is either 8-bit
776 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
780 the h/w is not re-initialized.
807 syscall, or to executing "dmesg -S --raw" or to reading
831 disable the cpuidle sub-system
837 disable the cpufreq sub-system
845 [X86] Delay for N microsec between assert and de-assert
857 Run kdump after running panic-notifiers and dumping
870 [KNL, X86-64, ARM64, RISCV] Select a region under 4G first, and
873 See Documentation/admin-guide/kdump/kdump.rst for further details.
878 start-[end] where start and end are both
880 Documentation/admin-guide/kdump/kdump.rst for an example.
883 [KNL, X86-64, ARM64, RISCV] range could be above 4G.
890 [KNL, X86-64, ARM64, RISCV] range under 4G. When crashkernel=X,high
895 low memory is needed to make sure DMA buffers for 32-bit
899 --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
900 --> arm64: 128MiB
901 --> riscv: 128MiB
909 [KNL] Disable crypto self-tests
917 csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
932 See also Documentation/input/devices/joystick-parport.rst
945 [KNL] verbose locking self-tests
948 self-tests.
950 (no extra messages), setting it to -1 (all bits set)
951 will print _a_lot_ more information - normally only
986 Format: { on, no-mount, off }
988 no-mount:
993 get a -EPERM as result when trying to register files
997 Default value is set in build-time with a kernel configuration.
1009 Documentation/admin-guide/mm/hugetlbpage.rst.
1023 delayacct [KNL] Enable per-task delay accounting
1103 memory out of your available memory pool based on
1118 entries for DMA-API debugging code. One entry is
1119 required per DMA-API allocation. Use this if the
1120 DMA-API debugging code disables itself because the
1124 With this option the DMA-API debugging driver
1148 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1162 Generic built-in EDID data sets are used, if one of
1167 available in Documentation/admin-guide/edid.rst. An EDID
1179 Control how the dt_cpu_ftrs device-tree binding is
1189 what data is available or for reverse-engineering.
1194 Documentation/admin-guide/dynamic-debug-howto.rst
1205 determined by stdout-path property in device tree's
1210 Start an early, polled-mode console on a Cadence
1221 Start an early, polled-mode console on the 8250/16550
1223 MMIO inter-register address stride is either 8-bit
1224 (mmio) or 32-bit (mmio32 or mmio32be).
1234 Start an early, polled-mode console on a pl011 serial
1238 the driver will use only 32-bit accessors to read/write
1247 Start an early, polled-mode console on a meson serial
1253 Start an early, polled-mode console on an msm serial
1259 Start an early, polled-mode console on an msm serial
1265 Start an early, polled-mode console on a serial port
1271 Start an early, polled-mode console on a serial port
1277 Use RISC-V SBI (Supervisor Binary Interface) for early
1295 Start an early, polled-mode console on a lantiq serial
1309 Start an early, polled-mode, output-only console on the
1314 Start an early, polled-mode console on the
1320 Start an early, polled-mode console on a Qualcomm
1328 coherent non-x86 systems that use system memory for
1428 attribute is added to range 0x100000000-0x180000000 and
1429 0x10a0000000-0x1120000000.
1433 range 0x240000000-0x43fffffff.
1445 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1462 elanfreq= [X86-32]
1470 See Documentation/admin-guide/kdump/kdump.rst for details.
1486 0 -- permissive (log only, no denials).
1487 1 -- enforcing (deny and log).
1519 See also Documentation/fault-injection/.
1523 See Documentation/admin-guide/sysctl/net.rst for
1527 See Documentation/admin-guide/blockdev/floppy.rst.
1530 [IA-64] Avoid check_sal_cache_flush which may hang on
1535 forcepae [X86-32]
1571 ftrace_filter=[function-list]
1573 tracer at boot up. function-list is a comma-separated
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
1591 ftrace_graph_notrace=[function-list]
1593 function-list. This list is a comma-separated list of
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
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
1749 during restoration read-only).
1775 hpet= [X86-32,HPET] option to control HPET usage
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.
1857 i2c_bus= [HW] Override the default board specific I2C bus speed
1858 or register an additional I2C bus that is not
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
1906 -1 -- never invert brightness
1907 0 -- machine default
1908 1 -- force brightness inversion
1922 idle=nomwait: Disable mwait for CPU C-states
1950 legacy only accept legacy-NaN binaries, if supported
1952 2008 only accept 2008-NaN binaries, if supported
1961 'relaxed' straps the emulator for both legacy-NaN and
1962 2008-NaN, whereas 'strict' enables legacy-NaN only on
1971 Ignore loglevel setting - this will print /all/
2038 Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" |
2039 "ima-sigv2" }
2040 Default: "ima-ng"
2073 stuff: Deploy RSB-fill mitigation when retpoline is
2078 Documentation/admin-guide/hw-vuln/indirect-target-selection.rst
2089 initcall_blacklist= [KNL] Do not execute a comma-separated list of
2090 initcall functions. Useful for debugging built-in
2135 0 -- basic integrity auditing messages. (Default)
2136 1 -- additional integrity auditing messages.
2164 could harm performance of some high-throughput
2173 1 to 9 specify maximum depth of C-state.
2182 algorithms for p-state selection. There are two
2183 P-state selection algorithms provided by
2186 on whether or not the hardware managed P-states
2193 used along with the hardware-managed P-states (HWP)
2197 in favor of acpi-cpufreq. Forcing the intel_pstate driver
2198 instead of acpi-cpufreq may disable platform features, such
2200 P-States information being indicated to OSPM and therefore
2203 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
2216 Allow per-logical-CPU P-State performance control limits using
2219 intremap= [X86-64, Intel-IOMMU]
2224 BIOS x2APIC opt-out request will be ignored
2248 0 - Try to allocate a 32-bit DMA address first, before
2250 1 - Allocate directly from the full usable range,
2252 greater than 32-bit addressing.
2256 0 - Lazy mode.
2262 1 - Strict mode.
2265 unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
2267 legacy driver-specific options takes precedence.
2272 0 - Use IOMMU translation for DMA.
2273 1 - Bypass the IOMMU for DMA.
2274 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2276 io7= [HW] IO7 for Marvel-based Alpha systems
2291 See Documentation/admin-guide/nfs/nfsroot.rst.
2315 Enables support for pseudo-NMIs in the kernel. This
2334 [Deprecated - use cpusets instead]
2335 Format: [flag-list,]<cpu-list>
2366 "number of CPUs in system - 1".
2392 The format of <cpu-list> is described above.
2396 ivrs_ioapic [HW,X86-64]
2397 Provide an override to the IOAPIC-ID<->DEVICE-ID
2401 For example, to map IOAPIC-ID decimal 10 to
2407 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2410 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2414 ivrs_hpet [HW,X86-64]
2415 Provide an override to the HPET-ID<->DEVICE-ID
2419 For example, to map HPET-ID decimal 10 to
2425 * To map HPET-ID decimal 0 to PCI device 00:14.0
2428 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2432 ivrs_acpihid [HW,X86-64]
2433 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2437 For example, to map UART-HID:UID AMD0020:0 to
2443 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2446 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2467 kernelcore= [KNL,X86,IA-64,PPC]
2470 the kernel for non-movable allocations. The requested
2480 subsystem. Note that allocations like PTEs-from-HighMem
2488 for non-movable allocations and remaining memory is used
2499 gdb or control-c on the dbgp connection. When
2500 not using this parameter you use sysrq-g to break into
2505 or a supported polling keyboard driver (non-usb).
2532 Configure the RouterBoard 532 series on-chip
2535 kmemleak= [KNL] Boot-time kmemleak enable/disable
2541 kprobe_event=[probe-list]
2543 The probe-list is a semicolon delimited list of probe
2573 execution by eliminating the write-protection faults
2618 back to huge pages. If the value is a non-zero N, KVM will
2623 kvm-amd.nested= [KVM,AMD] Control nested virtualization feature in
2626 kvm-amd.npt= [KVM,AMD] Control KVM's use of Nested Page Tables,
2627 a.k.a. Two-Dimensional Page Tables. Default is 1
2631 kvm-arm.mode=
2636 nvhe: Standard nVHE-based mode, without support for
2639 protected: nVHE-based mode with support for guests whose
2642 nested: VHE-based mode with support for nested
2651 kvm-arm.vgic_v3_group0_trap=
2652 [KVM,ARM] Trap guest accesses to GICv3 group-0
2655 kvm-arm.vgic_v3_group1_trap=
2656 [KVM,ARM] Trap guest accesses to GICv3 group-1
2659 kvm-arm.vgic_v3_common_trap=
2663 kvm-arm.vgic_v4_enable=
2675 kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables,
2676 a.k.a. Two-Dimensional Page Tables. Default is 1
2680 kvm-intel.emulate_invalid_guest_state=
2682 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2688 kvm-intel.flexpriority=
2693 kvm-intel.nested=
2697 kvm-intel.unrestricted_guest=
2703 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2704 CVE-2018-3620.
2715 kvm-intel.vpid= [KVM,Intel] Control KVM's use of Virtual Processor
2735 on - enable the interface for the mitigation
2800 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
2806 lapic [X86-32,APIC] Enable the local APIC even if BIOS
2810 value for LAPIC timer one-shot implementation. Default
2833 libata.force= [LIBATA] Force configurations. The format is a comma-
2845 first fan-out link behind PMP device. It does not
2859 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
2866 * rstonce: only attempt one reset during hot-unplug
2948 Set the number of locking read-acquisition kthreads.
2953 Set the number of locking write-acquisition kthreads.
2956 Set time (s) after boot for CPU-hotplug testing.
2959 Set time (s) between CPU-hotplug operations, or
2960 zero to disable CPU-hotplug testing.
2963 Set task-shuffle interval (jiffies). Shuffling
2964 tasks allows some CPUs to go into dyntick-idle
2969 is useful for hands-off automated testing.
2985 Run the write-side locktorture kthreads at
2986 sched_set_fifo() real-time priority.
3006 7 (KERN_DEBUG) debug-level messages
3016 logo.nologo [FB] Disables display of the built-in Linux logo.
3034 an IEEE 1284-compliant printer is attached; if
3040 time-consuming boot-time autodetection (up to 250 ms per
3061 machvec= [IA-64] Force the use of a particular machine-vector
3067 Example: machtype=lemote-yeeloong-2f-7inch
3069 max_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory greater
3082 (loop.max_loop) unconditionally pre-created at init time. The default
3085 devices can be requested on-demand with the
3086 /dev/loop-control interface.
3088 mce [X86-32] Machine Check Exception
3090 mce=option [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
3093 See Documentation/admin-guide/md.rst.
3100 Control mitigation for the Micro-architectural Data
3115 full - Enable MDS mitigation on vulnerable CPUs
3116 full,nosmt - Enable MDS mitigation and disable
3118 off - Unconditionally disable MDS mitigation
3120 On TAA-affected machines, mds=off can be prevented by
3129 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3143 [ARC,MICROBLAZE] - the limit applies only to low memory,
3146 [ARM64] - only limits memory covered by the linear
3159 [ARM,MIPS] - override the memory layout reported by
3166 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3173 per-device physically contiguous DMA buffers.
3181 See Documentation/admin-guide/mm/memory-hotplug.rst.
3206 Example: Exclude memory from 0x18690000-0x1869ffff
3220 memmap=<size>%<offset>-<oldtype>+<newtype>
3222 from <oldtype> to <newtype>. If "-<oldtype>" is left
3237 repeatable BIOS-originated corruption always
3281 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3287 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
3291 s2idle - Suspend-To-Idle
3292 shallow - Power-On Suspend or equivalent (if supported)
3293 deep - Suspend-To-RAM or equivalent (if supported)
3294 See Documentation/admin-guide/pm/sleep-states.rst.
3299 mfgpt_irq= [IA-32] Specify the IRQ to use for the
3300 Multi-Function General Purpose Timers on AMD Geode
3303 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
3315 min_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory below this
3322 0 - The attached screen is the 3.5" TFT
3323 1 - The attached screen is the 7" TFT
3324 2 - The VGA Shield is attached (1024x768)
3328 b - Enable backlight. The TFT backlight pin will be
3332 c - Enable the s3c camera interface.
3333 t - Reserved for enabling touchscreen support. The
3337 https://repo.or.cz/w/linux-2.6/mini2440.git
3342 arch-independent options, each of which is an
3343 aggregation of existing arch-specific options.
3372 ssbd=force-off [ARM64]
3385 have other ways of avoiding SMT-based attacks.
3420 full - Enable mitigation on vulnerable CPUs
3422 full,nosmt - Enable mitigation and disable SMT on
3425 off - Unconditionally disable mitigation
3438 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3468 module_blacklist= [KNL] Do not load a comma-separated list of
3482 movablecore= [KNL,X86,IA-64,PPC]
3493 movable_node [KNL] Boot-time switch to make hotplugable memory
3500 Format: <name>,<region-number>,<size>,<offset>
3503 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3511 See arch/arm/mach-s3c/mach-jive.c
3547 something different and driver-specific.
3580 [NFS] enable 64-bit inode numbers.
3581 If zero, the NFS client will fake up a 32-bit inode
3583 of returning the full 64-bit number.
3584 The default is to return 64-bit inode numbers.
3619 [NFS4] Specify an additional fixed unique ident-
3650 driver. A non-zero value sets the minimum interval
3655 server-to-server copies for which this server is
3667 server-to-server copy, knfsd temporarily mounts
3674 See Documentation/admin-guide/nfs/nfsroot.rst.
3676 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3677 See Documentation/admin-guide/nfs/nfsroot.rst.
3680 See Documentation/admin-guide/nfs/nfsroot.rst.
3684 NMI stack-backtrace request.
3693 0 - turn hardlockup detector in nmi_watchdog off
3694 1 - turn hardlockup detector in nmi_watchdog on
3706 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
3710 no4lvl [RISCV] Disable 4-level and 5-level paging modes. Forces
3711 kernel to use 3-level paging instead.
3713 no5lvl [X86-64,RISCV] Disable 5-level paging mode. Forces
3714 kernel to use 4-level paging instead.
3717 caches in the slab allocator. Saves per-node memory,
3754 no_entry_flush [PPC] Don't flush the L1-D cache when entering the kernel.
3756 noexec [IA-64]
3758 noexec32 [X86-64]
3759 This affects only 32-bit executables.
3760 noexec32=on: enable non-executable mappings (default)
3762 noexec32=off: disable non-executable mappings
3773 nofxsr [BUGS=X86-32] Disables x86 floating point extended
3775 legacy floating-point registers on task switch.
3777 nohalt [IA-64] Tells the kernel not to use the power saving
3779 power-consumption. On the positive side, it reduces
3780 interrupt wake-up latency, which may improve performance
3782 real-time systems.
3792 compared. However, if this command-line option is
3833 nointremap [X86-64, Intel-IOMMU] Do not enable interrupt
3835 [Deprecated - use intremap=off]
3837 nointroute [IA-64]
3843 noirqdebug [X86-32] Disables the code which attempts to detect and
3848 nojitter [IA-64] Disables jitter checking for ITC timers.
3855 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
3858 no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
3860 nolapic [X86-32,APIC] Do not enable or use the local APIC.
3862 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
3864 nomca [IA-64] Disable machine check abort handling
3866 nomce [X86-32] Disable Machine Check Exception
3868 nomfgpt [X86-32] Disable Multi-Function General Purpose
3874 not load if they could possibly displace the pre-
3877 perform display-mode changes or accelerated rendering.
3890 nopcid [X86-64] Disable the PCID cpu feature.
3895 nopti [X86-64]
3911 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
3917 nosbagart [IA-64]
3919 no-scroll [VGA] Disables scrollback.
3920 This is required for the Braillex ib80-piezo Braille
3923 nosgx [X86-64,SGX] Disables Intel SGX kernel support.
3943 nosoftlockup [KNL] Disable the soft-lockup detector.
3948 nospectre_bhb [ARM64] Disable all mitigations for Spectre-BHB (branch
3961 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES] Disable paravirtualized
3971 [PPC] Don't flush the L1-D cache after accessing user data.
3984 no-vmw-sched-clock
3989 soft-lockup and NMI watchdog (hard-lockup).
3993 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
4001 enabling legacy floating-point and sse state.
4027 nptcg= [IA-64] Override max number of concurrent global TLB
4036 n. So during boot up some boot time memory for per-cpu
4037 variables need be pre-allocated for later physical cpu
4052 See Documentation/admin-guide/sysctl/vm.rst for details.
4055 See Documentation/core-api/debugging-via-ohci1394.rst for more
4067 For example, to override I2C bus2:
4070 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4074 boundary - index of last SLC block on Flex-OneNAND.
4076 lock - Configure if Flex-OneNAND boundary should be locked.
4090 running on a platform with a direct-mapped memory-side
4096 page_owner= [KNL] Boot-time page_owner enabling option.
4102 page_poison= [KNL] Boot-time parameter changing the state of
4129 See Documentation/admin-guide/tainted-kernels.rst for
4181 Set to non-zero to probe primary and secondary ISA
4187 Set to non-zero if a chip is present that snoops speed
4235 Set to non-zero to probe tertiary and further ISA
4251 Set to non-zero to probe QDI controllers. By default
4256 Set to non-zero to probe Winbond controllers. Use
4303 bios [X86-32] force use of PCI BIOS, don't access
4305 has a non-standard PCI host bridge.
4306 nobios [X86-32] disallow use of PCI BIOS, only direct
4312 data in IO port 0xCFC, both 32-bit).
4314 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4315 the function, IO port 0xCFA, also 8-bit, sets
4317 through ports 0xC000-0xCFFF).
4324 root domains (aka PCI segments, in ACPI-speak).
4332 disable the use of MSI interrupts system-wide.
4337 primary IO-APIC for bridges that cannot disable
4344 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4368 F0000h-100000h range.
4373 assign-busses [X86] Always assign all PCI bus
4394 <linux-pci@vger.kernel.org>.
4398 a bug to <linux-pci@vger.kernel.org>.
4410 bfsort Sort PCI devices into breadth-first order.
4413 nobfsort Don't sort PCI devices into breadth-first order.
4415 tuning and use the BIOS-configured MPS defaults.
4425 configuration allows peer-to-peer DMA between
4428 that hot-added devices will work.
4443 A PCI-PCI bridge can be specified if resource
4449 for 4096-byte alignment.
4451 end-to-end CRC checking). Only effective if
4482 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4518 dpc-native Use native PCIe service for DPC only. May
4535 Keep all power-domains already enabled by bootloader on,
4552 pirq= [SMP,APIC] Manual mp-table setup
4553 See Documentation/arch/x86/i386/IO-APIC.rst.
4557 See also Documentation/admin-guide/parport.rst.
4576 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4585 { on | off | curr | res | no-curr | no-res }
4625 none - Limited to cond_resched() calls
4626 voluntary - Limited to cond_resched() and might_sleep() calls
4627 full - Any section that isn't explicitly preempt disabled
4630 print-fatal-signals=
4636 coredump - etc.
4639 you might want to try "ulimit -i unlimited".
4651 or lockdep-detected issues (only if lock debug is on).
4660 on - unlimited logging to /dev/kmsg from userspace
4661 off - logging to /dev/kmsg disabled
4662 ratelimit - ratelimit the logging
4673 - 'always': traditional behavior always allows mem overrides.
4674 - 'ptrace': only allow mem overrides for active ptracers.
4675 - 'never': never allow mem overrides.
4679 Limit processor to maximum C-state
4683 Ignore the _CST method to determine C-states,
4690 Param: "schedule" - profile schedule points.
4691 Param: "kvm" - profile VM exits.
4692 Param: <number> - step/bucket size as a power of 2 for
4721 pti= [X86-64] Control Page Table Isolation of user and
4726 on - unconditionally enable
4727 off - unconditionally disable
4728 auto - kernel detects whether your CPU model is
4734 [KNL] Number of legacy pty's. Overwrites compiled-in
4746 See Documentation/admin-guide/md.rst.
4749 See Documentation/admin-guide/blockdev/ramdisk.rst.
4768 cross-syscall address exposures. This is only
4774 ras=option[,option,...] [KNL] RAS-specific options
4780 rcu_nocbs[=cpu-list]
4785 enable the no-callback CPU mode, which prevents
4790 "p" for RCU-preempt, "s" for RCU-sched, and "g"
4794 and real-time workloads. It can also improve
4798 list of CPUs is set to no-callback mode from boot.
4802 no-callback mode from boot but the mode may be
4813 This improves the real-time response for the
4830 RCU grace-period cleanup.
4834 RCU grace-period initialization.
4838 RCU grace-period pre-initialization, that is,
4839 the propagation of recent CPU-hotplug changes up
4843 Set delay from grace-period initialization to
4856 soliciting quiescent-state help from
4868 Set the SCHED_FIFO priority of the RCU per-CPU
4871 and for the RCU grace-period kthreads (rcu_bh,
4873 set, valid values are 1-99 and the default is 1
4874 (the least-favored priority). Otherwise, when
4875 RCU_BOOST is not set, valid values are 0-99 and
4876 the default is zero (non-realtime operation).
4881 On callback-offloaded (rcu_nocbs) CPUs,
4884 use of the ->nocb_bypass list. However, in the
4885 common non-flooded case, RCU queues directly to
4886 the main ->cblist in order to avoid the extra
4887 overhead of the ->nocb_bypass list and its lock.
4889 a single jiffy, RCU pre-queues the callbacks into
4890 the ->nocb_bypass queue. The definition of "too
4899 batch limiting is re-enabled.
4903 RCU's force-quiescent-state scan will aggressively
4911 Set the page-cache refill delay (in milliseconds)
4912 in response to low-memory conditions. The range
4916 Set the shift-right count to use to compute
4917 the callback-invocation batch limit bl from
4924 Please note that this callback-invocation batch
4925 limit applies only to non-offloaded callback
4934 cache-to-cache transfer latencies.
4940 and for NUMA systems with large remote-access
4956 the wakeup overhead on the global grace-period
4958 each group's NOCB grace-period kthread.
4961 Cause the grace-period kthread to get an extra
4963 it should at force-quiescent-state time.
4976 this specifies an rcu_read_unlock()-time delay
4980 of RCU-protected pointers after the relevant
4990 per-CPU rcuc kthreads. Defaults to a non-zero
5000 grace-period primitives such as call_rcu().
5011 grace-period primitives.
5014 Set test-start holdoff period. The purpose of
5032 Test the double-argument variant of kfree_rcu().
5034 rcuscale.kfree_rcu_test_single, both the single-
5035 and double-argument variants are tested.
5038 Test the single-argument variant of kfree_rcu().
5040 rcuscale.kfree_rcu_test_double, both the single-
5041 and double-argument variants are tested.
5055 does not affect the data-collection interval,
5060 Set number of RCU readers. The value -1 selects
5062 "n" less than -1 selects N-n+1, where N is again
5063 the number of CPUs. For example, -2 selects N
5064 (the number of CPUs), -3 selects N+1, and so on.
5065 A value of "n" less than or equal to -N selects
5078 complete. This is useful for hands-off automated
5085 Write-side holdoff between grace periods,
5090 Additional write-side holdoff between grace
5108 for RCU grace-period forward-progress testing
5115 Specify the fraction of a CPU-stall-warning
5116 period to do tight-loop forward-progress testing.
5120 forward-progress tests.
5124 need_resched() during tight-loop forward-progress
5128 Use conditional/asynchronous update-side
5132 Use expedited update-side primitives, if available.
5135 Use normal (non-expedited) asynchronous
5136 update-side primitives, if available.
5139 Use normal (non-expedited) synchronous
5140 update-side primitives, if available. If all
5144 they are all non-zero.
5152 Leak an RCU-protected pointer out of the reader.
5167 Set number of RCU callback-offload togglers.
5172 callback-offload toggling attempts.
5175 Set number of RCU readers. The value -1 selects
5176 N-1, where N is the number of CPUs. A value
5177 "n" less than -1 selects N-n-2, where N is again
5178 the number of CPUs. For example, -2 selects N
5179 (the number of CPUs), -3 selects N+1, and so on.
5182 Enable debug-object double-call_rcu() testing.
5185 Set time (s) after boot for CPU-hotplug testing.
5188 Set time (jiffies) between CPU-hotplug operations,
5189 or zero to disable CPU-hotplug testing.
5192 Set the number of read-then-exit kthreads used
5194 task-exit processing.
5197 The number of times in a given read-then-exit
5198 episode that a set of read-then-exit kthreads
5203 read-then-exit testing episodes.
5206 Set task-shuffle interval (s). Shuffling tasks
5207 allows some CPUs to go into dyntick-idle mode
5212 is useful for hands-off automated testing.
5221 any other stall-related activity. Note that
5227 in scheduling-while-atomic splats.
5240 grace-period kthread to test RCU CPU stall
5266 Test RCU's dyntick-idle handling. See also the
5315 Use expedited grace-period primitives, for
5319 real-time latency, and degrade energy efficiency.
5323 Use only normal grace-period primitives,
5326 real-time latency, CPU utilization, and
5328 increased grace-period latency. This parameter
5335 only normal grace-period primitives. No effect
5341 post-boot attempt at an expedited RCU grace
5342 period to instead use normal non-expedited
5343 grace-period processing.
5351 set to the default value of -1.
5354 Set the minimum number of callback-queuing-time
5355 lock-contention events per jiffy required to
5356 cause the RCU Tasks flavors to switch to per-CPU
5359 the default value of -1.
5364 of -1 allows this to be automatically (and
5372 number avoids disturbing real-time workloads,
5377 cancel laziness on that CPU. Use -1 to disable
5387 only printed prior to the stall-warning message
5443 force - Override the decision by the kernel to hide the
5471 Set test-start holdoff period. The purpose of
5480 but the default has already reduced the per-pass
5485 Set number of readers. The default value of -1
5494 Set the read-side critical-section duration,
5498 Specify the read-protection implementation to test.
5517 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
5525 reservetop= [X86-32]
5542 See Documentation/power/swsusp-and-swap-files.rst
5557 AMD-based UNRET and IBPB mitigations alone do not stop
5559 sibling threads. For that reason, STIBP is used on pro-
5563 off - no mitigation
5564 auto - automatically select a migitation
5565 auto,nosmt - automatically select a mitigation,
5569 ibpb - On AMD, mitigate short speculation
5574 ibpb,nosmt - Like "ibpb" above but will disable SMT
5578 unret - Force enable untrained return thunks,
5579 only effective on AMD f15h-f17h based
5581 unret,nosmt - Like unret, but will disable SMT when STIBP
5616 ro [KNL] Mount root device read-only on boot
5619 on Mark read-only kernel memory as read-only (default).
5620 off Leave read-only kernel memory writable for debugging.
5621 full Mark read-only kernel memory and aliases as read-only
5627 debug-uart get routed to the D+ and D- pins of the usb
5633 block/early-lookup.c for details.
5658 rw [KNL] Mount root device read-write on boot
5710 to 10 seconds for built-in smp_call_function()
5717 that requesting even small non-zero numbers of
5724 The default of -1 specifies a number of kthreads
5729 test before initiating CPU-hotplug operations.
5733 CPU-hotplug operations. Specifying zero (which
5734 is the default) disables CPU-hotplug operations.
5740 Non-zero values are useful for automated tests.
5763 "wait" parameter. A value of -1 selects the
5764 default if all other weights are -1. However,
5766 value of -1 will instead select a weight of zero.
5771 non-zero "wait" parameter. See weight_single.
5784 non-zero "wait" parameter. See weight_single
5796 non-zero "wait" parameter. See weight_single
5803 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
5804 1 -- enable.
5815 0 -- disable.
5816 1 -- enable.
5819 serialnumber [BUGS=X86-32]
5821 sev=option[,option...] [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
5829 to set it to "all" by meaning -- no limit here.
5835 simeth= [IA-64]
5910 using the csdlock_debug- kernel parameter.
5915 system. By default, let CSD-lock acquisition
5917 for this value provides a 5-minute timeout.
5919 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
5920 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
5921 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
5922 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
5923 smsc-ircc2.ircc_irq= [HW] IRQ line
5924 smsc-ircc2.ircc_dma= [HW] DMA channel
5925 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
5935 Default: -1 (no limit)
5938 [KNL] Should the soft-lockup detector generate panics.
5941 A value of 1 instructs the soft-lockup detector
5942 to panic the machine when a soft-lockup occurs. It is
5945 respective build-time switch to that functionality.
5948 [KNL] Should the soft-lockup detector generate
5953 See Documentation/admin-guide/laptops/sonypi.rst
5960 on - (default) Enable the HW or SW mitigation
5962 off - Disable the mitigation.
5969 on - unconditionally enable, implies
5971 off - unconditionally disable, implies
5973 auto - kernel detects whether your CPU model is
5992 retpoline - replace indirect branches
5993 retpoline,generic - Retpolines
5994 retpoline,lfence - LFENCE; indirect branch
5995 retpoline,amd - alias for retpoline,lfence
5996 eibrs - Enhanced/Auto IBRS
5997 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
5998 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
5999 ibrs - use IBRS to protect kernel
6009 on - Unconditionally enable mitigations. Is
6012 off - Unconditionally disable mitigations. Is
6015 prctl - Indirect branch speculation is enabled,
6021 - Like "prctl" above, but only STIBP is
6027 - Same as "prctl" above, but all seccomp
6032 - Like "seccomp" above, but only STIBP is
6037 auto - Kernel selects the mitigation depending on
6048 off - Disable mitigation
6049 microcode - Enable microcode mitigation only
6050 safe-ret - Enable sw-only safe RET mitigation (default)
6051 ibpb - Enable mitigation by issuing IBPB on
6053 ibpb-vmexit - Issue IBPB only on VMEXIT
6054 (cloud-specific mitigation)
6079 on - Unconditionally disable Speculative Store Bypass
6080 off - Unconditionally enable Speculative Store Bypass
6081 auto - Kernel detects whether the CPU model contains an
6087 prctl - Control Speculative Store Bypass per thread
6091 seccomp - Same as "prctl" above, but all seccomp threads
6099 on,auto - On Power8 and Power9 insert a store-forwarding
6103 off - No action.
6122 off - not enabled
6124 warn - the kernel will emit rate-limited warnings
6132 fatal - the kernel will send SIGBUS to applications
6137 ratelimit:N -
6157 Certain CPUs are vulnerable to an MDS-like
6177 This kernel-boot parameter defaults to 128,
6178 but takes effect only when the low-order four
6195 instead of the compile-time CONFIG_NR_CPUS.
6199 grace-period sequence counter wrap for the
6200 srcu_data structure's ->srcu_gp_seq_needed field.
6215 Specifies the number of no-delay instances
6222 Specifies the per-grace-period phase, number of
6223 non-sleeping polls of readers. Beyond this limit,
6229 Specifies number of microseconds of non-sleeping
6230 delay between each non-sleeping poll of readers.
6233 Specifies the number of update-side contention
6238 set for contention-based conversions to occur.
6248 force-on: Unconditionally enable mitigation for
6250 force-off: Unconditionally disable mitigation for
6273 stacktrace_filter=[function-list]
6275 will trace at boot up. function-list is a comma-separated
6283 Set the STI (builtin display/keyboard on the HP-PARISC
6285 as the initial boot-console.
6342 global a single global pool contains all CPUs
6343 percpu one pool for each CPU
6344 pernode one pool for each NUMA node (equivalent
6345 to global on non-NUMA machines)
6368 swiotlb= [ARM,IA-64,PPC,MIPS,X86]
6370 <int> -- Number of I/O TLB slabs
6371 <int> -- Second integer after comma. Number of swiotlb
6374 force -- force using of bounce buffers even if they
6376 noforce -- Never use bounce buffers (for debugging)
6391 Ignore sysrq setting - this boot parameter will
6399 cache size. See Documentation/networking/ip-sysctl.rst
6406 Specify "mem" (for Suspend-to-RAM) or "standby" (for
6411 wakeup-capable RTC alarm.
6417 -1: disable all active trip points in all thermal zones
6421 -1: disable all critical trip points in all thermal zones
6428 -1: disable all passive trip points
6434 <deci-seconds>: poll all this frequency
6456 Prevent the CPU-hotplug component of torturing
6460 Dump the ftrace buffer at torture-test shutdown,
6464 with rotating-rust storage.
6469 disables verbose-printk() sleeping.
6472 Duration of each verbose-printk() sleep in jiffies.
6490 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
6528 local - Use the per CPU time stamp counter
6532 global - Event time stamps are synchronize across
6535 counter - Simple counting of events (1, 2, ..)
6539 uptime - Use jiffies as the time stamp.
6540 perf - Use the same clock that perf uses.
6541 mono - Use ktime_get_mono_fast_ns() for time stamps.
6542 mono_raw - Use ktime_get_raw_fast_ns() for time
6544 boot - Use ktime_get_boot_fast_ns() for time stamps.
6548 trace_event=[event-list]
6550 to facilitate early boot debugging. The event-list is a
6551 comma-separated list of trace events to enable. See
6554 trace_instance=[instance-info]
6574 trace_options=[option-list]
6576 The option-list is a comma delimited list of options
6590 trace_trigger=[trigger-list]
6627 See Documentation/admin-guide/mm/transhuge.rst
6635 - "tpm"
6636 - "tee"
6637 - "caam"
6647 - "kernel"
6648 - the same value as trusted.source: "tpm" or "tee"
6649 - "default"
6658 high-resolution timer mode on older hardware, and in
6694 on - Enable TSX on the system. Although there are
6697 several previous speculation-related CVEs, and
6701 off - Disable TSX on the system. (Note that this
6709 auto - Disable TSX if X86_BUG_TAA is present,
6714 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
6720 Similar to Micro-architectural Data Sampling (MDS)
6735 full - Enable TAA mitigation on vulnerable CPUs
6738 full,nosmt - Enable TAA mitigation and disable SMT on
6741 vulnerable to cross-thread TAA attacks.
6742 off - Unconditionally disable TAA mitigation
6744 On MDS-affected machines, tsx_async_abort=off can be
6756 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
6762 See also Documentation/input/devices/joystick-parport.rst
6764 udbg-immortal [PPC] When debugging early kernel crashes that
6770 Set number of hash buckets for UDP/UDP-Lite connections
6772 uhci-hcd.ignore_oc=
6774 Some badly-designed motherboards generate lots of
6783 unwind_debug [X86-64]
6791 (default -1 = authorized (same as 1),
6797 for newly-detected USB devices (default 2). This
6825 [USB] Specifies timeout for the initial 64-byte
6832 [USB] A list of quirk entries to augment the built-in
6835 VendorID:ProductID:Flags. The IDs are 4-digit hex
6837 will change the built-in quirk; setting it if it is
6842 a 255-byte read);
6846 Set-Interface requests);
6865 (bInterval-1).
6903 usb-storage.delay_use=
6907 usb-storage.quirks=
6909 override the built-in unusual_devs list. List
6912 and Product ID values (4-digit hex numbers) and
6914 to a common usb-storage quirk flag as follows:
6956 medium is write-protected).
6965 1 - undefined instruction events
6966 2 - system calls
6967 4 - invalid data aborts
6968 8 - SIGSEGV faults
6969 16 - SIGBUS faults
6980 On X86_32, this is an alias for vdso32=. Otherwise:
6985 vdso32= [X86] Control the 32-bit vDSO
6986 vdso32=1: enable 32-bit VDSO
6987 vdso32=0 or vdso32=2: disable 32-bit VDSO
6994 alias for vdso32=0.
6997 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
6999 vector= [IA-64,SMP]
7031 vga= [BOOT,X86-32] Select a particular video mode
7033 Documentation/admin-guide/svga.rst.
7048 - Disable all of the above options
7069 vsyscall= [X86-64]
7072 code). Most statically-linked binaries and older
7096 see VGA-softcursor.txt. Default: 2 = underline.
7101 This is a 16-member array composed of values
7102 ranging from 0-255.
7107 This is a 16-member array composed of values
7108 ranging from 0-255.
7113 This is a 16-member array composed of values
7114 ranging from 0-255.
7119 Set system-wide default UTF-8 mode for all tty's.
7120 Default is 1, i.e. UTF-8 mode is enabled for all
7125 Format=<-1|0|1>
7126 Set system-wide default for whether a cursor
7127 is shown on new VTs. Default is -1,
7132 vt.italic= [VT] Default color for italic text; 0-15.
7135 vt.underline= [VT] Default color for underlined text; 0-15.
7139 see Documentation/watchdog/watchdog-parameters.rst
7140 or other driver-specific files in the
7154 Format: <cpu-list>
7168 Per-cpu work items which run for longer than this
7171 them from noticeably delaying other per-cpu work
7180 Per-cpu workqueues are generally preferred because
7182 locality; unfortunately, per-cpu workqueues tend to
7185 Enabling this makes the per-cpu workqueues which
7199 Documentation/core-api/workqueue.rst.
7212 forces round-robin CPU selection to flush out
7220 on - Enable writecombine, use WUC for ioremap_wc()
7221 off - Disable writecombine, use SUC for ioremap_wc()
7223 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
7227 xen_512gb_limit [KNL,X86-64,XEN]
7237 ide-disks -- unplug primary master IDE devices
7238 aux-ide-disks -- unplug non-primary-master IDE devices
7239 nics -- unplug network devices
7240 all -- unplug all emulated devices (NICs and IDE disks)
7241 unnecessary -- unplugging emulated devices is
7244 never -- do not unplug even if version check succeeds
7252 Select whether to always use non-faulting (safe) MSR
7277 xen_timer_slop= [X86-64,XEN]
7302 preferred over the 2-level event handling, as it is
7319 xive.store-eoi=off [PPC]
7325 xhci-hcd.quirks [USB,KNL]