Lines Matching +full:edac +full:- +full:enabled
1 ACPI ACPI support is enabled.
2 AGP AGP (Accelerated Graphics Port) is enabled.
3 ALSA ALSA sound support is enabled.
4 APIC APIC support is enabled.
5 APM Advanced Power Management support is enabled.
6 APPARMOR AppArmor support is enabled.
7 ARM ARM architecture is enabled.
8 ARM64 ARM64 architecture is enabled.
9 CLK Common clock infrastructure is enabled.
10 CMA Contiguous Memory Area support is enabled.
11 DRM Direct Rendering Management support is enabled.
14 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
15 EFI EFI Partitioning (GPT) is enabled
17 FB The frame buffer device is enabled.
18 FTRACE Function tracing enabled.
19 GCOV GCOV profiling is enabled.
20 HIBERNATION HIBERNATION is enabled.
21 HW Appropriate hardware is enabled.
22 HYPER_V HYPERV support is enabled.
23 IMA Integrity measurement architecture is enabled.
24 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
25 IPV6 IPv6 support is enabled.
26 ISAPNP ISA PnP code is enabled.
27 ISOL CPU Isolation is enabled.
28 JOY Appropriate joystick support is enabled.
29 KGDB Kernel debugger support is enabled.
30 KVM Kernel Virtual Machine support is enabled.
31 LIBATA Libata driver is enabled
32 LOONGARCH LoongArch architecture is enabled.
33 LOOP Loopback device support is enabled.
34 LP Printer support is enabled.
35 M68k M68k architecture is enabled.
37 Documentation/arch/m68k/kernel-options.rst.
38 MIPS MIPS architecture is enabled.
39 MOUSE Appropriate mouse support is enabled.
41 MTD MTD (Memory Technology Device) support is enabled.
42 NET Appropriate network support is enabled.
43 NFS Appropriate NFS support is enabled.
44 NUMA NUMA support is enabled.
45 OF Devicetree is enabled.
46 PARISC The PA-RISC architecture is enabled.
47 PCI PCI bus support is enabled.
48 PCIE PCI Express support is enabled.
49 PCMCIA The PCMCIA subsystem is enabled.
50 PNP Plug & Play support is enabled.
51 PPC PowerPC architecture is enabled.
52 PPT Parallel port support is enabled.
53 PS2 Appropriate PS/2 support is enabled.
54 PV_OPS A paravirtualized kernel is enabled.
55 RAM RAM disk support is enabled.
57 RISCV RISCV architecture is enabled.
58 S390 S390 architecture is enabled.
59 SCSI Appropriate SCSI support is enabled.
61 the Documentation/scsi/ sub-directory.
62 SDW SoundWire support is enabled.
63 SECURITY Different security models are enabled.
64 SELINUX SELinux support is enabled.
65 SERIAL Serial support is enabled.
66 SH SuperH architecture is enabled.
68 SPARC Sparc architecture is enabled.
69 SUSPEND System suspend states are enabled.
70 SWSUSP Software suspend (hibernation) is enabled.
71 TPM TPM drivers are enabled.
72 UMS USB Mass Storage support is enabled.
73 USB USB support is enabled.
74 NVME NVMe support is enabled
75 USBHID USB Human Interface Device support is enabled.
76 V4L Video For Linux support is enabled.
77 VGA The VGA console has been enabled.
78 VMMIO Driver for memory mapped virtio devices is enabled.
79 VT Virtual terminal support is enabled.
80 WDT Watchdog support is enabled.
81 X86-32 X86-32, aka i386 architecture is enabled.
82 X86-64 X86-64 architecture is enabled.
83 X86 Either 32-bit or 64-bit x86 (same as X86-32+X86-64)
84 X86_UV SGI UV support is enabled.
85 XEN Xen support is enabled
86 XTENSA xtensa architecture is enabled.
92 KNL Is a kernel start-up parameter.
112 force -- enable ACPI if default was off
113 on -- enable ACPI but allow fallback to DT [arm64,riscv64]
114 off -- disable ACPI if default was on
115 noirq -- do not use ACPI for IRQ routing
116 strict -- Be less tolerant of platforms that are not
118 rsdt -- prefer RSDT over (default) XSDT
119 copy_dsdt -- copy DSDT to memory
120 nocmcff -- Disable firmware first mode for corrected
124 nospcr -- disable console in ACPI SPCR table as
126 spcr -- enable console in ACPI SPCR table as
143 If set to vendor, prefer vendor-specific driver
167 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
175 Documentation/firmware-guide/acpi/debug.rst for more information about
241 Format: <byte> or <bitmap-list>
244 Disable auto-serialization of AML methods
247 auto-serialization feature.
248 This feature is enabled by default.
265 Ignore the ACPI-based watchdog interface (WDAT) and let
286 acpi_osi=! # disable all built-in OS vendor
288 acpi_osi=!! # enable all built-in OS vendor
350 For broken nForce2 BIOS resulting in XT-PIC timer.
359 as soon as the kernel's real-mode entry point is called.
367 s4_hwsig option is enabled.
397 See Documentation/sound/alsa-configuration.rst
404 align_va_addr= [X86-64]
408 machines (where it is enabled by default) for a
409 CPU-intensive style benchmark, and it can vary highly in
412 32: only for 32-bit processes
413 64: only for 64-bit processes
414 on: enable for both 32- and 64-bit processes
415 off: disable for both 32- and 64-bit processes
425 Allow execve() of 32-bit applications and setting of the
427 subset of the CPUs support 32-bit EL0. When this
428 parameter is present, the set of CPUs supporting 32-bit
430 and hot-unplug operations may be restricted.
432 See Documentation/arch/arm64/asymmetric-32bit.rst for more
435 amd_iommu= [HW,X86-64]
438 fullflush - Deprecated, equivalent to iommu.strict=1
439 off - do not initialize any AMD IOMMU found in
441 force_isolation - Force device isolation for all
446 force_enable - Force enable the IOMMU on platforms known
447 to be buggy with IOMMU enabled. Use this
449 pgtbl_v1 - Use v1 page table for DMA-API (Default).
450 pgtbl_v2 - Use v2 page table for DMA-API.
451 irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
452 nohugepages - Limit page-sizes used for v1 page-tables
454 v2_pgsizes_only - Limit page-sizes used for v1 page-tables
458 amd_iommu_dump= [HW,X86-64]
460 for AMD IOMMU. With this option enabled, AMD IOMMU
464 amd_iommu_intr= [HW,X86-64]
467 legacy - Use legacy interrupt remapping mode.
468 vapic - Use virtual APIC mode, which allows IOMMU
470 This mode requires kvm-amd.avic=1.
499 Disable amd-pstate preferred core.
504 Disable amd-pstate dynamic EPP.
506 Enable amd-pstate dynamic EPP.
519 Power management functions (SPARCstation-4/5 + deriv.)
521 Disable APC CPU standby support. SPARCstation-Fox does
522 not play well with APC CPU idle - disable it if you have
525 apic [APIC,X86-64] Use IO-APIC. Default.
531 when initialising the APIC and IO-APIC components.
555 0 -- disable.
556 1 -- enable.
607 audit= [KNL] Enable the audit sub-system
609 0 | off - kernel audit is disabled and can not be
610 enabled until the next reboot
611 unset - kernel audit is initialized but disabled and
612 will be fully enabled by the userspace auditd.
613 1 | on - kernel audit is initialized and partially
614 enabled, storing at most audit_backlog_limit
615 messages in RAM until it is fully enabled by the
626 0 - Disable the BAU.
627 1 - Enable the BAU.
628 unset - Disable the BAU.
650 See Documentation/block/cmdline-partition.rst
654 Only works if CONFIG_BOOT_PRINTK_DELAY is enabled,
664 See Documentation/admin-guide/bootconfig.rst
669 bttv.pll= See Documentation/admin-guide/media/bttv.rst
678 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
697 inclusive. See arch/mips/include/asm/pgtable-bits.h
704 cfi= [X86-64] Set Control Flow Integrity checking features
705 when CONFIG_FINEIBT is enabled.
715 norand: Do not re-randomize CFI hashes.
725 - foo isn't auto-mounted if you mount all cgroups in
727 - foo isn't visible as an individually mountable
729 - if foo is an optional feature then the feature is
735 Specifying "pressure" disables per-cgroup pressure
752 semi-legacy software can check this file to decide
761 nosocket -- Disable socket memory accounting.
762 nokmem -- Disable kernel memory accounting.
763 nobpf -- Disable BPF memory accounting.
767 double-frees, use-after-frees, and other sources of
776 0 -- check protection applied by kernel (includes
778 1 -- check protection requested by application.
790 clocks that have not been explicitly enabled by a Linux
791 device driver but are enabled in hardware at reset or
793 force such clocks to be always-on nor does it reserve
797 information, see Documentation/driver-api/clk.rst.
799 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
816 [X86-32] pit,hpet,tsc;
823 [X86-64] hpet,tsc
829 architected timer so that code using WFE-based polling
843 clocksource-wdtest.holdoff= [KNL]
849 cma=nn[MG]@[start[MG][-end[MG]]]
860 Sets the size of kernel per-numa memory area for
862 per-numa CMA altogether. And If this option is not
864 With per-numa CMA enabled, DMA users on node nid will
879 With numa CMA enabled, DMA users on node nid will
921 See Documentation/admin-guide/serial-console.rst for more
936 $ ls -d /sys/bus/serial-base/devices/*:*.*/tty/*
937 /sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0
950 Start an early, polled-mode console on the 8250/16550
953 MMIO inter-register address stride is either 8-bit
954 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
958 the h/w is not re-initialized.
985 syscall, or to executing "dmesg -S --raw" or to reading
1009 disable the cpuidle sub-system
1015 disable the cpufreq sub-system
1023 [X86,EARLY] Delay for N microsec between assert and de-assert
1031 Default is enabled if CONFIG_HOTPLUG_PARALLEL=y. Otherwise
1044 like Hyper-V, PowerPC (fadump) and AMD SEV-SNP.
1052 [KNL, X86-64, ARM64, RISCV, LoongArch] Select a region
1055 See Documentation/admin-guide/kdump/kdump.rst for further details.
1060 start-[end] where start and end are both
1062 Documentation/admin-guide/kdump/kdump.rst for an example.
1065 [KNL, X86-64, ARM64, RISCV, LoongArch] range could be
1073 [KNL, X86-64, ARM64, RISCV, LoongArch] range under 4G.
1079 for 32-bit devices won't run out. Kernel would try to allocate
1082 --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
1083 --> arm64: 128MiB
1084 --> riscv: 128MiB
1085 --> loongarch: 128MiB
1115 [KNL] Disable crypto self-tests
1123 csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
1138 See also Documentation/input/devices/joystick-parport.rst
1144 boot sequence. If enabled, we use a weak hash instead
1151 [KNL] verbose locking self-tests
1154 self-tests.
1156 (no extra messages), setting it to -1 (all bits set)
1157 will print _a_lot_ more information - normally only
1193 on: All functions are enabled.
1195 get a -EPERM as result when trying to register files
1198 debugfs was not enabled in the kernel at all.
1199 Default value is set in build-time with a kernel configuration.
1211 Documentation/admin-guide/mm/hugetlbpage.rst.
1226 delayacct [KNL] Enable per-task delay accounting
1312 entries for DMA-API debugging code. One entry is
1313 required per DMA-API allocation. Use this if the
1314 DMA-API debugging code disables itself because the
1318 With this option the DMA-API debugging driver
1319 filter feature can be enabled at boot time. Just
1338 are enabled. In order to disable RFDS mitigation all
1342 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1345 [KNL] When set to 1, leave the dm-verity keyring
1374 Control how the dt_cpu_ftrs device-tree binding is
1384 what data is available or for reverse-engineering.
1389 Documentation/admin-guide/dynamic-debug-howto.rst
1400 determined by stdout-path property in device tree's
1405 Start an early, polled-mode console on a Cadence
1416 Start an early, polled-mode console on the 8250/16550
1418 MMIO inter-register address stride is either 8-bit
1419 (mmio) or 32-bit (mmio32 or mmio32be).
1429 Start an early, polled-mode console on a pl011 serial
1433 the driver will use only 32-bit accessors to read/write
1442 Start an early, polled-mode console on a meson serial
1448 Start an early, polled-mode console on an msm serial
1454 Start an early, polled-mode console on an msm serial
1460 Start an early, polled-mode console on a serial port
1466 Start an early, polled-mode console on a serial port
1472 Use RISC-V SBI (Supervisor Binary Interface) for early
1490 Start an early, polled-mode console on a lantiq serial
1504 Start an early, polled-mode, output-only console on the
1509 Start an early, polled-mode console on the
1515 Start an early, polled-mode console on a Qualcomm
1523 coherent non-x86 systems that use system memory for
1547 the normal console is initialized. It is not enabled by
1584 edac_report= [HW,EDAC] Control how to report EDAC event
1586 on: enable EDAC to report H/W event. May be overridden
1588 off: disable H/W event reporting through EDAC.
1589 force: enforce the use of EDAC to report H/W event.
1626 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1647 See Documentation/admin-guide/kdump/kdump.rst for details.
1663 0 -- permissive (log only, no denials).
1664 1 -- enforcing (deny and log).
1697 See also Documentation/fault-injection/.
1701 See Documentation/admin-guide/sysctl/net.rst for
1705 See Documentation/admin-guide/blockdev/floppy.rst.
1707 forcepae [X86-32]
1714 fred= [X86-64]
1765 ftrace_filter=[function-list]
1767 tracer at boot up. function-list is a comma-separated
1772 ftrace_notrace=[function-list]
1774 function-list. This list can be changed at run time
1778 ftrace_graph_filter=[function-list]
1781 function-list is a comma-separated list of functions
1785 ftrace_graph_notrace=[function-list]
1787 function-list. This list is a comma-separated list of
1807 off -- Don't create device links from firmware info.
1808 permissive -- Create device links from firmware info
1811 on -- Create device links from firmware info and use it
1813 rpm -- Like "on", but also use to order runtime PM.
1826 strict -- Default. Continue waiting on consumers to
1828 timeout -- Give up waiting on consumers and call
1838 See also Documentation/input/devices/joystick-parport.rst
1842 gart_fix_e820= [X86-64,EARLY] disable the fix e820 for K8 GART
1868 gcov_persist= [GCOV] When non-zero (default), profiling data for
1878 gpio-mockup.gpio_mockup_ranges
1881 gpio-mockup.gpio_mockup_named_lines
1909 hardening is enabled for this boot. Hardened
1913 against bounds-checking flaws in the kernel's
1921 [KNL] Should the hard-lockup detector generate
1937 auto - Hash pointers unless slab_debug is enabled.
1938 always - Always hash pointers (even if slab_debug is
1939 enabled).
1940 never - Never hash pointers. This option should only
1951 for 64-bit NUMA, off otherwise.
1959 corresponding firmware-first mode error processing
1969 during restoration read-only).
2023 hpet= [X86-32,HPET] option to control HPET usage
2027 force: allow force enabled of undocumented chips (ICH4,
2040 number of pages to allocate per-node can be specified.
2041 See also Documentation/admin-guide/mm/hugetlbpage.rst.
2052 Documentation/admin-guide/mm/hugetlbpage.rst.
2062 Note that this parameter only applies to non-gigantic huge pages.
2071 When using node format, this applies to each per-node size.
2075 hugepages using the CMA allocator. If enabled, the
2076 boot-time allocation of gigantic hugepages is skipped.
2087 enabled.
2088 Control if HugeTLB Vmemmap Optimization (HVO) is enabled.
2101 enabled, those vmemmap pages cannot be optimized even if this
2102 feature is enabled. Other vmemmap pages not allocated from
2109 When set to a non-zero value, a kernel panic will be triggered if
2117 CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value
2123 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
2145 Set device-properties for ACPI-enumerated I2C-attached
2146 touchscreen, to e.g. fix coordinates of upside-down
2154 Omit "=<val>" entirely Set a boolean device-property
2155 Unsigned number Set a u32 device-property
2156 Anything else Set a string device-property
2159 i2c_touchscreen_props=GDIX1001:touchscreen-inverted-x:
2160 touchscreen-inverted-y
2162 i2c_touchscreen_props=MSSL1680:touchscreen-size-x=1920:
2163 touchscreen-size-y=1080:touchscreen-inverted-y:
2164 firmware-name=gsl1680-vendor-model.fw:silead,home-button
2169 (disabled by default, and as a pre-condition
2170 requires that i8042.debug=1 be enabled)
2171 i8042.direct [HW] Put keyboard port into non-translated mode
2185 suspend-to-ram transitions, only during s2r
2209 -1 -- never invert brightness
2210 0 -- machine default
2211 1 -- force brightness inversion
2213 ia32_emulation= [X86-64]
2215 When true, allows loading 32-bit programs and executing 32-bit
2237 idle=nomwait: Disable mwait for CPU C-states
2265 legacy only accept legacy-NaN binaries, if supported
2267 2008 only accept 2008-NaN binaries, if supported
2278 'relaxed' straps the emulator for both legacy-NaN and
2279 2008-NaN, whereas 'strict' enables legacy-NaN only on
2288 Ignore loglevel setting - this will print /all/
2361 Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" |
2362 "ima-sigv2" }
2363 Default: "ima-ng"
2384 stuff: Deploy RSB-fill mitigation when retpoline is
2389 Documentation/admin-guide/hw-vuln/indirect-target-selection.rst
2400 initcall_blacklist= [KNL] Do not execute a comma-separated list of
2401 initcall functions. Useful for debugging built-in
2446 0 -- basic integrity auditing messages. (Default)
2447 1 -- additional integrity auditing messages.
2473 Do not force the Intel IOMMU enabled under tboot.
2475 could harm performance of some high-throughput
2477 mapping is enabled.
2484 1 to 9 specify maximum depth of C-state.
2493 algorithms for p-state selection. There are two
2494 P-state selection algorithms provided by
2497 on whether or not the hardware managed P-states
2498 (HWP) feature has been enabled in the processor
2504 used along with the hardware-managed P-states (HWP)
2508 in favor of acpi-cpufreq. Forcing the intel_pstate driver
2509 instead of acpi-cpufreq may disable platform features, such
2511 P-States information being indicated to OSPM and therefore
2514 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
2527 Allow per-logical-CPU P-State performance control limits using
2530 Do not enable capacity-aware scheduling (CAS) on
2533 intremap= [X86-64,Intel-IOMMU,EARLY]
2538 BIOS x2APIC opt-out request will be ignored
2562 Do scatter-gather (SG) merging. Implies "force"
2566 Don't do scatter-gather (SG) merging.
2569 Do scatter-gather (SG) merging. Implies "force"
2595 AMD Gart HW IOMMU-specific options: (CONFIG_GART_IOMMU)
2629 0 - Try to allocate a 32-bit DMA address first, before
2631 1 - Allocate directly from the full usable range,
2633 greater than 32-bit addressing.
2637 0 - Lazy mode.
2643 1 - Strict mode.
2646 unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
2648 legacy driver-specific options takes precedence.
2653 0 - Use IOMMU translation for DMA.
2654 1 - Bypass the IOMMU for DMA.
2655 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2663 0 - Sanitizer disabled.
2664 1 - Sanitizer enabled, expect runtime overhead.
2666 io7= [HW] IO7 for Marvel-based Alpha systems
2681 See Documentation/admin-guide/nfs/nfsroot.rst.
2694 Start IPE with success auditing enabled, emitting
2717 Enables support for pseudo-NMIs in the kernel. This
2722 [RISC-V,EARLY]
2724 as IPIs. Intended for system where IMSIC is trap-n-emulated,
2736 long-running IRQs in the system.
2748 Format: [flag-list,]<cpu-list>
2775 Documentation/admin-guide/cpu-isolation.rst.
2780 "number of CPUs in system - 1".
2806 The format of <cpu-list> is described above.
2810 ivrs_ioapic [HW,X86-64]
2811 Provide an override to the IOAPIC-ID<->DEVICE-ID
2815 For example, to map IOAPIC-ID decimal 10 to
2821 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2824 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2828 ivrs_hpet [HW,X86-64]
2829 Provide an override to the HPET-ID<->DEVICE-ID
2833 For example, to map HPET-ID decimal 10 to
2839 * To map HPET-ID decimal 0 to PCI device 00:14.0
2842 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2846 ivrs_acpihid [HW,X86-64]
2847 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2851 For example, to map UART-HID:UID AMD0020:0 to
2857 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2860 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2884 the kernel for non-movable allocations. The requested
2894 subsystem. Note that allocations like PTEs-from-HighMem
2902 for non-movable allocations and remaining memory is used
2913 [MM,KFENCE] Whether to check all KFENCE-managed objects'
2920 allocations. This avoids forcing CPU wake-ups if the
2928 report - print the error report and continue (default).
2929 oops - print the error report and oops.
2930 panic - print the error report and panic.
2935 0 - Disable KFENCE.
2936 >0 - Enabled KFENCE with given sample interval.
2954 gdb or control-c on the dbgp connection. When
2955 not using this parameter you use sysrq-g to break into
2960 or a supported polling keyboard driver (non-usb).
2989 "0" | "off" | "n" - kexec handover is disabled
2990 "1" | "on" | "y" - kexec handover is enabled
2996 ranges that can only be used for non-kernel
3007 parameter defines the size of additional per-node
3012 Configure the RouterBoard 532 series on-chip
3015 kmemleak= [KNL,EARLY] Boot-time kmemleak enable/disable
3021 kprobe_event=[probe-list]
3023 The probe-list is a semicolon delimited list of probe
3036 Default: enabled on cores which need mitigation.
3038 1: force enabled
3041 CONFIG_KUNIT to be set to be fully enabled. The
3044 Default is 1 (enabled)
3053 execution by eliminating the write-protection faults
3063 KVM_DIRTY_LOG_INITIALLY_SET is enabled or disabled. If
3065 split when dirty logging is enabled on that memslot. If
3066 enabled, eager page splitting will be performed during
3075 If enabled, KVM will virtualize PMU functionality based
3077 can be overridden on a per-VM basis via
3085 with an in-kernel local APIC, e.g. to deliver PMIs to
3086 the guest. Running without an in-kernel local APIC is
3095 If enabled, KVM will enable virtualization in hardware
3100 virtualization on-demand when creating and destroying
3108 is that doing so may interfere with using out-of-tree
3124 If the software workaround is enabled for the host,
3135 back to huge pages. If the value is a non-zero N, KVM will
3140 kvm-{amd,intel}.enable_mediated_pmu=[KVM,AMD,INTEL]
3141 If enabled, KVM will provide a mediated virtual PMU,
3142 instead of the default perf-based virtual PMU (if
3146 With a perf-based vPMU, KVM operates as a user of perf,
3148 KVM-created perf events are managed by perf as regular
3149 (guest-only) events, e.g. are scheduled in/out, contend
3150 for hardware resources, etc. Using a perf-based vPMU
3151 allows guest and host usage of the PMU to co-exist, but
3152 incurs non-trivial overhead and can result in silently
3164 to profile KVM guests and adds latency to most VM-Exits
3169 kvm-amd.nested= [KVM,AMD] Control nested virtualization feature in
3170 KVM/SVM. Default is 1 (enabled).
3172 kvm-amd.npt= [KVM,AMD] Control KVM's use of Nested Page Tables,
3173 a.k.a. Two-Dimensional Page Tables. Default is 1
3174 (enabled). Disable by KVM if hardware lacks support
3177 kvm-amd.ciphertext_hiding_asids=
3182 If ciphertext hiding is enabled, the joint SEV-ES and
3183 SEV-SNP ASID space is partitioned into separate SEV-ES
3184 and SEV-SNP ASID ranges, with the SEV-SNP range being
3185 [1..max_snp_asid] and the SEV-ES range being
3189 A non-zero value enables SEV-SNP ciphertext hiding and
3190 adjusts the ASID ranges for SEV-ES and SEV-SNP guests.
3191 KVM caps the number of SEV-SNP ASIDs at the maximum
3192 possible value, e.g. specifying -1u will assign all
3193 joint SEV-ES and SEV-SNP ASIDs to SEV-SNP. Note,
3194 assigning all joint ASIDs to SEV-SNP, i.e. configuring
3195 max_snp_asid == min_sev_asid-1, will effectively make
3196 SEV-ES unusable.
3198 kvm-arm.mode=
3204 nvhe: Standard nVHE-based mode, without support for
3211 nested: VHE-based mode with support for nested
3219 command-line.
3223 kvm-arm.vgic_v3_group0_trap=
3224 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-0
3227 kvm-arm.vgic_v3_group1_trap=
3228 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-1
3231 kvm-arm.vgic_v3_common_trap=
3235 kvm-arm.vgic_v4_enable=
3239 kvm-arm.wfe_trap_policy=
3248 kvm-arm.wfi_trap_policy=
3265 kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables,
3266 a.k.a. Two-Dimensional Page Tables. Default is 1
3267 (enabled). Disable by KVM if hardware lacks support
3270 kvm-intel.emulate_invalid_guest_state=
3272 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
3276 Default is 1 (enabled).
3278 kvm-intel.flexpriority=
3280 (TPR shadow). Default is 1 (enabled). Disable by KVM if
3283 kvm-intel.nested=
3285 KVM/VMX. Default is 1 (enabled).
3287 kvm-intel.unrestricted_guest=
3290 is 1 (enabled). Disable by KVM if EPT is disabled or
3293 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
3294 CVE-2018-3620.
3305 kvm-intel.vpid= [KVM,Intel] Control KVM's use of Virtual Processor
3307 (enabled). Disable by KVM if hardware lacks support
3325 on - enable the interface for the mitigation
3331 enabled and cannot be disabled.
3344 i.e. SMT enabled or L1D flush disabled.
3353 Leaves SMT enabled and enables the default
3362 i.e. SMT enabled or L1D flush disabled.
3374 i.e. SMT enabled or L1D flush disabled.
3390 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
3396 lapic [X86-32,APIC,EARLY] Enable the local APIC even if BIOS
3400 value for LAPIC timer one-shot implementation. Default
3423 libata.force= [LIBATA] Force configurations. The format is a comma-
3435 first fan-out link behind PMP device. It does not
3449 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
3456 * rstonce: only attempt one reset during hot-unplug
3492 number of 512-byte sectors, to the value specified in
3494 a non-zero positive integer.
3504 * external: Mark port as external (hotplug-capable).
3561 Specify the number of self-propagating call_rcu()
3569 occasional long-duration lock hold time. Defaults
3580 Set the number of locking read-acquisition kthreads.
3585 Set the number of locking write-acquisition kthreads.
3588 Set time (s) after boot for CPU-hotplug testing.
3591 Set time (s) between CPU-hotplug operations, or
3592 zero to disable CPU-hotplug testing.
3595 Do periodic testing of real-time lock priority
3600 non-real-time spinlocks, due to their disabling
3601 of preemption. Note that non-realtime mutexes
3614 Set task-shuffle interval (jiffies). Shuffling
3615 tasks allows some CPUs to go into dyntick-idle
3620 is useful for hands-off automated testing.
3639 Run the write-side locktorture kthreads at
3640 sched_set_fifo() real-time priority.
3658 7 (KERN_DEBUG) debug-level messages
3670 logo.nologo [FB] Disables display of the built-in Linux logo.
3688 an IEEE 1284-compliant printer is attached; if
3694 time-consuming boot-time autodetection (up to 250 ms per
3714 Example: machtype=lemote-yeeloong-2f-7inch
3726 (loop.max_loop) unconditionally pre-created at init time. The default
3729 devices can be requested on-demand with the
3730 /dev/loop-control interface.
3732 mce= [X86-{32,64}]
3769 do not opt-in to Local MCE delivery. Use legacy method
3780 enabled by default.
3790 don't overwrite the bios-set CMCI threshold. This boot
3799 force-enable recoverable machine check code paths
3805 See Documentation/admin-guide/md.rst.
3808 Control mitigation for the Micro-architectural Data
3823 full - Enable MDS mitigation on vulnerable CPUs
3824 full,nosmt - Enable MDS mitigation and disable
3826 off - Unconditionally disable MDS mitigation
3828 On TAA-affected machines, mds=off can be prevented by
3837 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3852 [ARC,MICROBLAZE] - the limit applies only to low memory,
3855 [ARM64] - only limits memory covered by the linear
3868 [ARM,MIPS,EARLY] - override the memory layout
3875 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3882 per-device physically contiguous DMA buffers.
3890 See Documentation/admin-guide/mm/memory-hotplug.rst.
3915 Example: Exclude memory from 0x18690000-0x1869ffff
3929 memmap=<size>%<offset>-<oldtype>+<newtype>
3931 from <oldtype> to <newtype>. If "-<oldtype>" is left
3946 repeatable BIOS-originated corruption always
3964 When enabled, runtime hotplugged memory will
3967 if hugetlb_free_vmemmap is enabled) from the
3977 Note that even when enabled, there are a few cases where
3990 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3996 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
4000 s2idle - Suspend-To-Idle
4001 shallow - Power-On Suspend or equivalent (if supported)
4002 deep - Suspend-To-RAM or equivalent (if supported)
4003 See Documentation/admin-guide/pm/sleep-states.rst.
4005 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
4015 base_rev=X - with <X> with format: <u32>
4029 0 - The attached screen is the 3.5" TFT
4030 1 - The attached screen is the 7" TFT
4031 2 - The VGA Shield is attached (1024x768)
4035 b - Enable backlight. The TFT backlight pin will be
4039 c - Enable the s3c camera interface.
4040 t - Reserved for enabling touchscreen support. The
4041 touchscreen support is not enabled in the mainstream
4044 https://repo.or.cz/w/linux-2.6/mini2440.git
4049 arch-independent options, each of which is an
4050 aggregation of existing arch-specific options.
4080 ssbd=force-off [ARM64]
4092 enabled, even if it's vulnerable. This is for
4095 have other ways of avoiding SMT-based attacks.
4109 supports attack-vector based controls as documented in
4110 Documentation/admin-guide/hw-vuln/attack_vector_controls.rst
4134 full - Enable mitigation on vulnerable CPUs
4136 full,nosmt - Enable mitigation and disable SMT on
4139 off - Unconditionally disable mitigation
4152 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
4182 module_blacklist= [KNL] Do not load a comma-separated list of
4207 movable_node [KNL,EARLY] Boot-time switch to make hotplugable memory
4214 Format: <name>,<region-number>,<size>,<offset>
4217 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
4288 Only applies if the softerr mount option is enabled,
4324 [NFS4] Specify an additional fixed unique ident-
4355 driver. A non-zero value sets the minimum interval
4360 server-to-server copies for which this server is
4372 server-to-server copy, knfsd temporarily mounts
4379 See Documentation/admin-guide/nfs/nfsroot.rst.
4381 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
4382 See Documentation/admin-guide/nfs/nfsroot.rst.
4385 See Documentation/admin-guide/nfs/nfsroot.rst.
4389 NMI stack-backtrace request.
4398 0 - turn hardlockup detector in nmi_watchdog off
4399 1 - turn hardlockup detector in nmi_watchdog on
4400 rNNN - configure the watchdog with raw perf event 0xNNN
4413 no4lvl [RISCV,EARLY] Disable 4-level and 5-level paging modes.
4414 Forces kernel to use 3-level paging instead.
4416 no5lvl [X86-64,RISCV,EARLY] Disable 5-level paging mode. Forces
4417 kernel to use 4-level paging instead.
4452 no_entry_flush [PPC,EARLY] Don't flush the L1-D cache when entering the kernel.
4454 noexec32 [X86-64]
4455 This affects only 32-bit executables.
4456 noexec32=on: enable non-executable mappings (default)
4458 noexec32=off: disable non-executable mappings
4469 nofxsr [BUGS=X86-32] Disables x86 floating point extended
4471 legacy floating-point registers on task switch.
4518 nointremap [X86-64,Intel-IOMMU,EARLY] Do not enable interrupt
4520 [Deprecated - use intremap=off]
4526 noirqdebug [X86-32] Disables the code which attempts to detect and
4536 no-kvmapf [X86,KVM,EARLY] Disable paravirtualized asynchronous page
4539 no-kvmclock [X86,KVM,EARLY] Disable paravirtualized KVM clock driver
4541 nolapic [X86-32,APIC,EARLY] Do not enable or use the local APIC.
4543 nolapic_timer [X86-32,APIC,EARLY] Do not use the local APIC timer.
4545 nomce [X86-32] Disable Machine Check Exception
4547 nomfgpt [X86-32] Disable Multi-Function General Purpose
4553 not load if they could possibly displace the pre-
4556 perform display-mode changes or accelerated rendering.
4569 nopcid [X86-64,EARLY] Disable the PCID cpu feature.
4574 nopti [X86-64,EARLY]
4590 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
4596 no-scroll [VGA] Disables scrollback.
4597 This is required for the Braillex ib80-piezo Braille
4600 nosgx [X86-64,SGX,EARLY] Disables Intel SGX kernel support.
4620 nosoftlockup [KNL] Disable the soft-lockup detector.
4626 nospectre_bhb [ARM64,EARLY] Disable all mitigations for Spectre-BHB (branch
4639 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,LOONGARCH,EARLY]
4646 timer IRQ sources, i.e., the IO-APIC timer. This can
4651 [PPC,EARLY] Don't flush the L1-D cache after accessing user data.
4664 no-vmw-sched-clock
4669 soft-lockup and NMI watchdog (hard-lockup).
4673 nox2apic [X86-64,APIC,EARLY] Do not enable x2APIC mode.
4681 enabling legacy floating-point and sse state.
4688 xsaveopt supports it on xsaveopt enabled systems.
4696 memory on xsaves enabled systems.
4703 n. So during boot up some boot time memory for per-cpu
4704 variables need be pre-allocated for later physical cpu
4731 soft-reserved memory partitioning.
4740 See Documentation/admin-guide/sysctl/vm.rst for details.
4742 nvme.quirks= [NVME] A list of quirk entries to augment the built-in
4744 '-' character.
4746 The IDs are 4-digits hex numbers and quirk_names is a
4752 nvme.quirks=7710:2267:bogus_nid,^identify_cns-9900:7711:broken_msi
4755 See Documentation/core-api/debugging-via-ohci1394.rst for more
4770 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4774 boundary - index of last SLC block on Flex-OneNAND.
4776 lock - Configure if Flex-OneNAND boundary should be locked.
4795 page_owner= [KNL,EARLY] Boot-time page_owner enabling option.
4801 page_poison= [KNL,EARLY] Boot-time parameter changing the state of
4829 See Documentation/admin-guide/tainted-kernels.rst for
4842 constraints, or platform-specific requirements where only
4916 Set to non-zero to probe primary and secondary ISA
4922 Set to non-zero if a chip is present that snoops speed
4970 Set to non-zero to probe tertiary and further ISA
4986 Set to non-zero to probe QDI controllers. By default
4991 Set to non-zero to probe Winbond controllers. Use
5036 bios [X86-32] force use of PCI BIOS, don't access
5038 has a non-standard PCI host bridge.
5039 nobios [X86-32] disallow use of PCI BIOS, only direct
5045 data in IO port 0xCFC, both 32-bit).
5047 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
5048 the function, IO port 0xCFA, also 8-bit, sets
5050 through ports 0xC000-0xCFFF).
5054 enabled, this kernel boot option can be used to
5057 root domains (aka PCI segments, in ACPI-speak).
5064 enabled, this kernel boot option can be used to
5065 disable the use of MSI interrupts system-wide.
5067 Safety option to keep boot IRQs enabled. This
5070 primary IO-APIC for bridges that cannot disable
5077 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
5101 F0000h-100000h range.
5106 assign-busses [X86] Always assign all PCI bus
5114 IRQ routing is enabled.
5119 is enabled by default. If you need to use this,
5127 <linux-pci@vger.kernel.org>.
5131 a bug to <linux-pci@vger.kernel.org>.
5143 bfsort Sort PCI devices into breadth-first order.
5146 nobfsort Don't sort PCI devices into breadth-first order.
5148 tuning and use the BIOS-configured MPS defaults.
5158 configuration allows peer-to-peer DMA between
5161 that hot-added devices will work.
5176 A PCI-PCI bridge can be specified if resource
5182 for 4096-byte alignment.
5184 end-to-end CRC checking). Only effective if
5215 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
5241 capabilities will be enabled, disabled or
5246 bit-0 : ACS Source Validation
5247 bit-1 : ACS Translation Blocking
5248 bit-2 : ACS P2P Request Redirect
5249 bit-3 : ACS P2P Completion Redirect
5250 bit-4 : ACS Upstream Forwarding
5251 bit-5 : ACS P2P Egress Control
5252 bit-6 : ACS Direct Translated P2P
5255 '1' – force enabled
5262 Validation unchanged from whatever power-up
5272 is enabled, this kernel boot option can be used
5274 system-wide.
5288 dpc-native Use native PCIe service for DPC only. May
5305 Keep all power-domains already enabled by bootloader on,
5323 pirq= [SMP,APIC] Manual mp-table setup
5324 See Documentation/arch/x86/i386/IO-APIC.rst.
5328 See also Documentation/admin-guide/parport.rst.
5347 resume of devices during system-wide power transitions.
5349 dependencies are not well-defined, or for debugging
5351 enabled by default.
5359 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
5368 { on | off | curr | res | no-curr | no-res }
5413 none - Limited to cond_resched() calls
5414 voluntary - Limited to cond_resched() and might_sleep() calls
5415 full - Any section that isn't explicitly preempt disabled
5419 lazy - Scheduler controlled. Similar to full but instead
5425 print-fatal-signals=
5428 If enabled, warn about various signal handling
5431 coredump - etc.
5434 you might want to try "ulimit -i unlimited".
5446 or lockdep-detected issues (only if lock debug is on).
5451 default: 0 (auto_verbose is enabled)
5454 Allows storing messages from non-panic CPUs into
5456 flushed to consoles by the panic-CPU on
5457 a best-effort basis.
5463 on - unlimited logging to /dev/kmsg from userspace
5464 off - logging to /dev/kmsg disabled
5465 ratelimit - ratelimit the logging
5476 - 'always': traditional behavior always allows mem overrides.
5477 - 'ptrace': only allow mem overrides for active ptracers.
5478 - 'never': never allow mem overrides.
5482 Limit processor to maximum C-state
5486 Ignore the _CST method to determine C-states,
5493 Param: "schedule" - profile schedule points.
5494 Param: "kvm" - profile VM exits.
5495 Param: <number> - step/bucket size as a power of 2 for
5500 that). If enabled, the default kernel base address
5520 0 = disabled, 1 = enabled (default).
5524 pti= [X86-64] Control Page Table Isolation of user and
5529 on - unconditionally enable
5530 off - unconditionally disable
5531 auto - kernel detects whether your CPU model is
5537 [KNL] Number of legacy pty's. Overwrites compiled-in
5549 See Documentation/admin-guide/md.rst.
5552 See Documentation/admin-guide/blockdev/ramdisk.rst.
5571 cross-syscall address exposures. This is only
5577 ras=option[,option,...] [KNL] RAS-specific options
5583 rcu_nocbs[=cpu-list]
5588 enable the no-callback CPU mode, which prevents
5593 "p" for RCU-preempt, "s" for RCU-sched, and "g"
5597 and real-time workloads. It can also improve
5601 list of CPUs is set to no-callback mode from boot.
5605 no-callback mode from boot but the mode may be
5616 This improves the real-time response for the
5627 Do only a one-line RCU CPU stall warning when
5628 there is an ongoing too-long CSD-lock wait.
5634 If triggered before the RCU grace-period machinery
5644 RCU grace-period cleanup.
5648 RCU grace-period initialization.
5652 RCU grace-period pre-initialization, that is,
5653 the propagation of recent CPU-hotplug changes up
5657 Set delay from grace-period initialization to
5670 soliciting quiescent-state help from
5682 Set the SCHED_FIFO priority of the RCU per-CPU
5685 and for the RCU grace-period kthreads (rcu_bh,
5687 set, valid values are 1-99 and the default is 1
5688 (the least-favored priority). Otherwise, when
5689 RCU_BOOST is not set, valid values are 0-99 and
5690 the default is zero (non-realtime operation).
5695 On callback-offloaded (rcu_nocbs) CPUs,
5698 use of the ->nocb_bypass list. However, in the
5699 common non-flooded case, RCU queues directly to
5700 the main ->cblist in order to avoid the extra
5701 overhead of the ->nocb_bypass list and its lock.
5703 a single jiffy, RCU pre-queues the callbacks into
5704 the ->nocb_bypass queue. The definition of "too
5708 On callback-offloaded (rcu_nocbs) CPUs, avoid
5721 batch limiting is re-enabled.
5725 RCU's force-quiescent-state scan will aggressively
5733 Set the page-cache refill delay (in milliseconds)
5734 in response to low-memory conditions. The range
5738 Set the shift-right count to use to compute
5739 the callback-invocation batch limit bl from
5746 Please note that this callback-invocation batch
5747 limit applies only to non-offloaded callback
5756 cache-to-cache transfer latencies.
5762 and for NUMA systems with large remote-access
5778 the wakeup overhead on the global grace-period
5780 each group's NOCB grace-period kthread.
5783 Cause the grace-period kthread to get an extra
5785 it should at force-quiescent-state time.
5798 this specifies an rcu_read_unlock()-time delay
5802 of RCU-protected pointers after the relevant
5812 per-CPU rcuc kthreads. Defaults to a non-zero
5842 grace-period primitives such as call_rcu().
5853 grace-period primitives.
5856 Set test-start holdoff period. The purpose of
5874 Test the double-argument variant of kfree_rcu().
5876 rcuscale.kfree_rcu_test_single, both the single-
5877 and double-argument variants are tested.
5880 Test the single-argument variant of kfree_rcu().
5882 rcuscale.kfree_rcu_test_double, both the single-
5883 and double-argument variants are tested.
5897 does not affect the data-collection interval,
5902 Set number of RCU readers. The value -1 selects
5904 "n" less than -1 selects N-n+1, where N is again
5905 the number of CPUs. For example, -2 selects N
5906 (the number of CPUs), -3 selects N+1, and so on.
5907 A value of "n" less than or equal to -N selects
5920 complete. This is useful for hands-off automated
5927 Write-side holdoff between grace periods,
5932 Additional write-side holdoff between grace
5950 for RCU grace-period forward-progress testing
5957 Specify the fraction of a CPU-stall-warning
5958 period to do tight-loop forward-progress testing.
5962 forward-progress tests.
5966 need_resched() during tight-loop forward-progress
5970 Use conditional/asynchronous update-side
5971 normal-grace-period primitives, if available.
5974 Use conditional/asynchronous update-side
5975 expedited-grace-period primitives, if available.
5978 Use conditional/asynchronous update-side
5979 normal-grace-period primitives that also take
5984 Use conditional/asynchronous update-side
5985 expedited-grace-period primitives that also take
6009 Use expedited update-side primitives, if available.
6012 Use normal (non-expedited) asynchronous
6013 update-side primitives, if available.
6016 Use polled update-side normal-grace-period
6020 Use polled update-side expedited-grace-period
6024 Use polled update-side normal-grace-period
6029 Use polled update-side expedited-grace-period
6053 Use normal (non-expedited) synchronous
6054 update-side primitives, if available. If all
6058 they are all non-zero.
6061 Enable grace-period wrap lag testing. Setting
6066 Set the value for grace-period wrap lag during
6081 the grace-period wrap lag will be set to the
6091 Leak an RCU-protected pointer out of the reader.
6106 Set number of RCU callback-offload togglers.
6111 callback-offload toggling attempts.
6114 Set number of RCU readers. The value -1 selects
6115 N-1, where N is the number of CPUs. A value
6116 "n" less than -1 selects N-n-2, where N is again
6117 the number of CPUs. For example, -2 selects N
6118 (the number of CPUs), -3 selects N+1, and so on.
6121 Enable debug-object double-call_rcu() testing.
6124 Set time (s) after boot for CPU-hotplug testing.
6127 Set time (jiffies) between CPU-hotplug operations,
6128 or zero to disable CPU-hotplug testing.
6132 by a high-priority FIFO real-time task. Set to
6141 second) between preemptions by a high-priority
6142 FIFO real-time task. This delay is mediated
6147 The number of times in a given read-then-exit
6148 episode that a set of read-then-exit kthreads
6153 read-then-exit testing episodes.
6158 are entered from low-order bit up, and are
6160 0x1 bit is normal readers, 0x2 NMI-safe readers,
6161 and 0x4 light-weight readers.
6164 Set task-shuffle interval (s). Shuffling tasks
6165 allows some CPUs to go into dyntick-idle mode
6170 is useful for hands-off automated testing.
6179 any other stall-related activity. Note that
6185 in scheduling-while-atomic splats.
6204 grace-period kthread to test RCU CPU stall
6228 of RCU priority-boost testing. Defaults to zero,
6235 Test RCU's dyntick-idle handling. See also the
6290 Use expedited grace-period primitives, for
6294 real-time latency, and degrade energy efficiency.
6298 Use only normal grace-period primitives,
6301 real-time latency, CPU utilization, and
6303 increased grace-period latency. This parameter
6310 only normal grace-period primitives. No effect
6316 post-boot attempt at an expedited RCU grace
6317 period to instead use normal non-expedited
6318 grace-period processing.
6326 set to the default value of -1.
6329 Set the minimum number of callback-queuing-time
6330 lock-contention events per jiffy required to
6331 cause the RCU Tasks flavors to switch to per-CPU
6334 the default value of -1.
6339 of -1 allows this to be automatically (and
6345 cancel laziness on that CPU. Use -1 to disable
6355 only printed prior to the stall-warning message
6395 force - Override the decision by the kernel to hide the
6410 is enabled use:
6439 There are some built-in platform specific "quirks"
6440 - you may see: "reboot: <name> series board detected.
6444 built-in quirk table, and use the generic default
6477 Set test-start holdoff period. The purpose of
6492 but the default has already reduced the per-pass
6497 Set number of readers. The default value of -1
6506 Set the read-side critical-section duration,
6510 Specify the read-protection implementation to test.
6536 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
6566 reservetop= [X86-32,EARLY]
6583 See Documentation/power/swsusp-and-swap-files.rst
6599 AMD-based UNRET and IBPB mitigations alone do not stop
6601 sibling threads. For that reason, STIBP is used on pro-
6605 off - no mitigation
6606 auto - automatically select a mitigation
6607 auto,nosmt - automatically select a mitigation,
6611 ibpb - On AMD, mitigate short speculation
6616 ibpb,nosmt - Like "ibpb" above but will disable SMT
6620 unret - Force enable untrained return thunks,
6621 only effective on AMD f15h-f17h based
6623 unret,nosmt - Like unret, but will disable SMT when STIBP
6649 When CONFIG_RISCV_ISA_FALLBACK is not enabled, permit
6663 ro [KNL] Mount root device read-only on boot
6666 on Mark read-only kernel memory as read-only (default).
6667 off Leave read-only kernel memory writable for debugging.
6668 noalias Mark read-only kernel memory as read-only but retain
6676 debug-uart get routed to the D+ and D- pins of the usb
6682 block/early-lookup.c for details.
6724 rw [KNL] Mount root device read-write on boot
6751 solution to mutex-based priority inversion.
6781 to 10 seconds for built-in smp_call_function()
6788 that requesting even small non-zero numbers of
6795 The default of -1 specifies a number of kthreads
6800 test before initiating CPU-hotplug operations.
6804 CPU-hotplug operations. Specifying zero (which
6805 is the default) disables CPU-hotplug operations.
6811 Non-zero values are useful for automated tests.
6834 "wait" parameter. A value of -1 selects the
6835 default if all other weights are -1. However,
6837 value of -1 will instead select a weight of zero.
6842 non-zero "wait" parameter. See weight_single.
6855 non-zero "wait" parameter. See weight_single
6867 non-zero "wait" parameter. See weight_single
6878 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
6879 1 -- enable.
6881 enabled if running jitter sensitive (HPC/RT) workloads.
6890 0 -- disable.
6891 1 -- enable.
6894 serialnumber [BUGS=X86-32]
6896 sev=option[,option...] [X86-64]
6902 Do not enable SEV-SNP (applies to host/hypervisor
6905 SEV-SNP guests.
6913 to set it to "all" by meaning -- no limit here.
6925 Documentation/admin-guide/mm/slab.rst.
6936 Documentation/admin-guide/mm/slab.rst.
6952 Documentation/admin-guide/mm/slab.rst.
6958 Documentation/admin-guide/mm/slab.rst.
6973 Documentation/admin-guide/mm/slab.rst.
7000 using the csdlock_debug- kernel parameter.
7005 system. By default, let CSD-lock acquisition
7007 for this value provides a 5-minute timeout.
7009 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
7010 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
7011 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
7012 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
7013 smsc-ircc2.ircc_irq= [HW] IRQ line
7014 smsc-ircc2.ircc_dma= [HW] DMA channel
7015 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
7025 Default: -1 (no limit)
7028 [KNL] Should the soft-lockup detector generate panics.
7031 A value of non-zero instructs the soft-lockup detector
7032 to panic the machine when a soft-lockup duration exceeds
7035 respective build-time switch to that functionality.
7038 [KNL] Should the soft-lockup detector generate
7043 See Documentation/admin-guide/laptops/sonypi.rst
7050 on - (default) Enable the HW or SW mitigation as
7053 vmexit - On systems which don't have the HW mitigation
7056 protected from VM-originated BHI attacks, but
7058 off - Disable the mitigation.
7065 on - unconditionally enable, implies
7067 off - unconditionally disable, implies
7069 auto - kernel detects whether your CPU model is
7088 retpoline - replace indirect branches
7089 retpoline,generic - Retpolines
7090 retpoline,lfence - LFENCE; indirect branch
7091 retpoline,amd - alias for retpoline,lfence
7092 eibrs - Enhanced/Auto IBRS
7093 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
7094 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
7095 ibrs - use IBRS to protect kernel
7105 on - Unconditionally enable mitigations. Is
7108 off - Unconditionally disable mitigations. Is
7111 prctl - Indirect branch speculation is enabled,
7112 but mitigation can be enabled via prctl
7117 - Like "prctl" above, but only STIBP is
7123 - Same as "prctl" above, but all seccomp
7128 - Like "seccomp" above, but only STIBP is
7133 auto - Kernel selects the mitigation depending on
7144 off - Disable mitigation
7145 microcode - Enable microcode mitigation only
7146 safe-ret - Enable sw-only safe RET mitigation (default)
7147 ibpb - Enable mitigation by issuing IBPB on
7149 ibpb-vmexit - Issue IBPB only on VMEXIT
7150 (cloud-specific mitigation)
7175 on - Unconditionally disable Speculative Store Bypass
7176 off - Unconditionally enable Speculative Store Bypass
7177 auto - Kernel detects whether the CPU model contains an
7183 prctl - Control Speculative Store Bypass per thread
7184 via prctl. Speculative Store Bypass is enabled
7187 seccomp - Same as "prctl" above, but all seccomp threads
7195 on,auto - On Power8 and Power9 insert a store-forwarding
7199 off - No action.
7205 [X86,EARLY] Split the LLC N-ways
7219 When enabled (and if hardware support is present), atomic
7225 off - not enabled
7227 warn - the kernel will emit rate-limited warnings
7233 enabled in hardware.
7235 fatal - the kernel will send SIGBUS to applications
7238 both features are enabled in hardware.
7240 ratelimit:N -
7260 Certain CPUs are vulnerable to an MDS-like
7280 This kernel-boot parameter defaults to 128,
7281 but takes effect only when the low-order four
7298 instead of the compile-time CONFIG_NR_CPUS.
7302 grace-period sequence counter wrap for the
7303 srcu_data structure's ->srcu_gp_seq_needed field.
7318 Specifies the number of no-delay instances
7325 Specifies the per-grace-period phase, number of
7326 non-sleeping polls of readers. Beyond this limit,
7332 Specifies number of microseconds of non-sleeping
7333 delay between each non-sleeping poll of readers.
7336 Specifies the number of update-side contention
7341 set for contention-based conversions to occur.
7351 force-on: Unconditionally enable mitigation for
7353 force-off: Unconditionally disable mitigation for
7375 stack traces. Pools are allocated on-demand up to this
7381 stacktrace_filter=[function-list]
7383 will trace at boot up. function-list is a comma-separated
7391 Set the STI (builtin display/keyboard on the HP-PARISC
7393 as the initial boot-console.
7456 to global on non-NUMA machines)
7481 <int> -- Number of I/O TLB slabs
7482 <int> -- Second integer after comma. Number of swiotlb
7485 force -- force using of bounce buffers even if they
7487 noforce -- Never use bounce buffers (for debugging)
7502 Ignore sysrq setting - this boot parameter will
7510 cache size. See Documentation/networking/ip-sysctl.rst
7517 Specify "mem" (for Suspend-to-RAM) or "standby" (for
7522 wakeup-capable RTC alarm.
7528 -1: disable all active trip points in all thermal zones
7532 -1: disable all critical trip points in all thermal zones
7539 -1: disable all passive trip points
7545 <deci-seconds>: poll all this frequency
7549 Format: <size>[KMG],<size>[KMG]:<state>;<size>[KMG]-<size>[KMG]:<state>
7554 See Documentation/admin-guide/mm/transhuge.rst for more
7562 Format: <size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy>
7568 See Documentation/admin-guide/mm/transhuge.rst for more
7580 Prevent the CPU-hotplug component of torturing
7584 Dump the ftrace buffer at torture-test shutdown,
7588 with rotating-rust storage.
7593 disables verbose-printk() sleeping.
7596 Duration of each verbose-printk() sleep in jiffies.
7629 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
7667 local - Use the per CPU time stamp counter
7671 global - Event time stamps are synchronized across
7674 counter - Simple counting of events (1, 2, ..)
7678 uptime - Use jiffies as the time stamp.
7679 perf - Use the same clock that perf uses.
7680 mono - Use ktime_get_mono_fast_ns() for time stamps.
7681 mono_raw - Use ktime_get_raw_fast_ns() for time
7683 boot - Use ktime_get_boot_fast_ns() for time stamps.
7687 trace_event=[event-list]
7689 to facilitate early boot debugging. The event-list is a
7690 comma-separated list of trace events to enable. See
7701 trace_instance=[instance-info]
7707 Events can be enabled at the time the instance is created
7726 traceoff - Have the tracing instance tracing disabled after it is created.
7727 traceprintk - Have trace_printk() write into this trace instance
7756 If the ring buffer is used for persistent bootups and has events enabled,
7774 trace_options=[option-list]
7776 The option-list is a comma delimited list of options
7777 that can be enabled or disabled just as if you were
7790 trace_trigger=[trigger-list]
7821 be enabled again by echoing '1' into the "tracing_on"
7836 See Documentation/admin-guide/mm/transhuge.rst
7843 See Documentation/admin-guide/mm/transhuge.rst
7850 See Documentation/admin-guide/mm/transhuge.rst
7858 - "tpm"
7859 - "tee"
7860 - "caam"
7861 - "dcp"
7862 - "pkwm"
7888 - "kernel"
7889 - the same value as trusted.source: "tpm" or "tee"
7890 - "default"
7913 off - disable the mitigation
7914 on - enable the mitigation (default)
7915 user - mitigate only user/kernel transitions
7916 vm - mitigate only guest/host transitions
7924 high-resolution timer mode on older hardware, and in
7955 on - Enable TSX on the system. Although there are
7958 several previous speculation-related CVEs, and
7960 with leaving it enabled.
7962 off - Disable TSX on the system. (Note that this
7970 auto - Disable TSX if X86_BUG_TAA is present,
7975 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7981 Similar to Micro-architectural Data Sampling (MDS)
7996 full - Enable TAA mitigation on vulnerable CPUs
7997 if TSX is enabled.
7999 full,nosmt - Enable TAA mitigation and disable SMT on
8002 vulnerable to cross-thread TAA attacks.
8003 off - Unconditionally disable TAA mitigation
8005 On MDS-affected machines, tsx_async_abort=off can be
8017 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
8023 See also Documentation/input/devices/joystick-parport.rst
8025 udbg-immortal [PPC] When debugging early kernel crashes that
8031 Set number of hash buckets for UDP/UDP-Lite connections
8033 uhci-hcd.ignore_oc=
8035 Some badly-designed motherboards generate lots of
8060 unwind_debug [X86-64,EARLY]
8068 (default -1 = authorized (same as 1),
8074 for newly-detected USB devices (default 2). This
8099 if the first one fails (default 1 = enabled).
8102 [USB] Specifies timeout for the initial 64-byte
8109 [USB] A list of quirk entries to augment the built-in
8112 VendorID:ProductID:Flags. The IDs are 4-digit hex
8114 will change the built-in quirk; setting it if it is
8119 a 255-byte read);
8123 Set-Interface requests);
8142 (bInterval-1).
8183 usb-storage.delay_use=
8190 usb-storage.quirks=
8192 override the built-in unusual_devs list. List
8195 and Product ID values (4-digit hex numbers) and
8197 to a common usb-storage quirk flag as follows:
8239 medium is write-protected).
8248 1 - undefined instruction events
8249 2 - system calls
8250 4 - invalid data aborts
8251 8 - SIGSEGV faults
8252 16 - SIGBUS faults
8261 vdso32= [X86] Control the 32-bit vDSO
8262 vdso32=1: enable 32-bit VDSO
8263 vdso32=0 or vdso32=2: disable 32-bit VDSO
8273 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
8304 vga= [BOOT,X86-32] Select a particular video mode
8306 Documentation/admin-guide/svga.rst.
8313 enabled on systems with a large amount of memory.
8314 All options are enabled by default, and this
8321 - Disable all of the above options
8347 hypervisor to a guest via speculative side-channels.
8349 off - disable the mitigation
8350 ibpb - use Indirect Branch Prediction Barrier
8352 force - force vulnerability detection even on
8355 vsyscall= [X86-64,EARLY]
8358 code). Most statically-linked binaries and older
8384 see vga-softcursor.rst. Default: 2 = underline.
8389 This is a 16-member array composed of values
8390 ranging from 0-255.
8395 This is a 16-member array composed of values
8396 ranging from 0-255.
8401 This is a 16-member array composed of values
8402 ranging from 0-255.
8407 Set system-wide default UTF-8 mode for all tty's.
8408 Default is 1, i.e. UTF-8 mode is enabled for all
8413 Format=<-1|0|1>
8414 Set system-wide default for whether a cursor
8415 is shown on new VTs. Default is -1,
8420 vt.italic= [VT] Default color for italic text; 0-15.
8423 vt.underline= [VT] Default color for underlined text; 0-15.
8427 see Documentation/watchdog/watchdog-parameters.rst
8428 or other driver-specific files in the
8442 Format: <cpu-list>
8469 The default is 0, which disables the time-based panic.
8472 Per-cpu work items which run for longer than this
8475 them from noticeably delaying other per-cpu work
8493 Per-cpu workqueues are generally preferred because
8495 locality; unfortunately, per-cpu workqueues tend to
8498 Enabling this makes the per-cpu workqueues which
8513 Documentation/core-api/workqueue.rst.
8526 forces round-robin CPU selection to flush out
8528 When enabled, memory and cache locality will be
8534 on - Enable writecombine, use WUC for ioremap_wc()
8535 off - Disable writecombine, use SUC for ioremap_wc()
8537 x2apic_phys [X86-64,APIC,EARLY] Use x2apic physical mode instead of
8541 xen_512gb_limit [KNL,X86-64,XEN]
8545 save/restore/migration must be enabled to handle larger
8556 ide-disks -- unplug primary master IDE devices
8557 aux-ide-disks -- unplug non-primary-master IDE devices
8558 nics -- unplug network devices
8559 all -- unplug all emulated devices (NICs and IDE disks)
8560 unnecessary -- unplugging emulated devices is
8563 never -- do not unplug even if version check succeeds
8572 bit, so it should only be enabled for obtaining extended
8577 Select whether to always use non-faulting (safe) MSR
8597 xen_timer_slop= [X86-64,XEN,EARLY]
8622 preferred over the 2-level event handling, as it is
8639 xive.store-eoi=off [PPC]
8645 xhci-hcd.quirks [USB,KNL]
8652 Controls if xmon debugger is enabled. Default is off.