diff options
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 227 |
1 files changed, 169 insertions, 58 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b98048b56ada..11fc28ecdb6d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -389,15 +389,15 @@ Use software keyboard repeat audit= [KNL] Enable the audit sub-system - Format: { "0" | "1" } (0 = disabled, 1 = enabled) - 0 - kernel audit is disabled and can not be enabled - until the next reboot + Format: { "0" | "1" | "off" | "on" } + 0 | off - kernel audit is disabled and can not be + enabled until the next reboot unset - kernel audit is initialized but disabled and will be fully enabled by the userspace auditd. - 1 - kernel audit is initialized and partially enabled, - storing at most audit_backlog_limit messages in - RAM until it is fully enabled by the userspace - auditd. + 1 | on - kernel audit is initialized and partially + enabled, storing at most audit_backlog_limit + messages in RAM until it is fully enabled by the + userspace auditd. Default: unset audit_backlog_limit= [KNL] Set the audit queue size limit. @@ -646,6 +646,20 @@ console=brl,ttyS0 For now, only VisioBraille is supported. + console_msg_format= + [KNL] Change console messages format + default + By default we print messages on consoles in + "[time stamp] text\n" format (time stamp may not be + printed, depending on CONFIG_PRINTK_TIME or + `printk_time' param). + syslog + Switch to syslog format: "<%u>[time stamp] text\n" + IOW, each message will have a facility and loglevel + prefix. The format is similar to one used by syslog() + syscall, or to executing "dmesg -S --raw" or to reading + from /proc/kmsg. + consoleblank= [KNL] The console blank (screen saver) timeout in seconds. A value of 0 disables the blank timer. Defaults to 0. @@ -917,9 +931,12 @@ earlycon= [KNL] Output early console device and options. - When used with no options, the early console is - determined by the stdout-path property in device - tree's chosen node. + [ARM64] The early console is determined by the + stdout-path property in device tree's chosen node, + or determined by the ACPI SPCR table. + + [X86] When used with no options the early console is + determined by the ACPI SPCR table. cdns,<addr>[,options] Start an early, polled-mode console on a Cadence @@ -1008,7 +1025,7 @@ address. The serial port must already be setup and configured. Options are not yet supported. - earlyprintk= [X86,SH,BLACKFIN,ARM,M68k,S390] + earlyprintk= [X86,SH,ARM,M68k,S390] earlyprintk=vga earlyprintk=efi earlyprintk=sclp @@ -1330,10 +1347,6 @@ If specified, z/VM IUCV HVC accepts connections from listed z/VM user IDs only. - hwthread_map= [METAG] Comma-separated list of Linux cpu id to - hardware thread id mappings. - Format: <cpu>:<hwthread> - keep_bootcon [KNL] Do not unregister boot console at start. This is only useful for debugging when something happens in the window @@ -1508,7 +1521,8 @@ ima_policy= [IMA] The builtin policies to load during IMA setup. - Format: "tcb | appraise_tcb | secure_boot" + Format: "tcb | appraise_tcb | secure_boot | + fail_securely" The "tcb" policy measures all programs exec'd, files mmap'd for exec, and all files opened with the read @@ -1523,6 +1537,11 @@ of files (eg. kexec kernel image, kernel modules, firmware, policy, etc) based on file signatures. + The "fail_securely" policy forces file signature + verification failure also on privileged mounted + filesystems with the SB_I_UNVERIFIABLE_SIGNATURE + flag. + ima_tcb [IMA] Deprecated. Use ima_policy= instead. Load a policy which meets the needs of the Trusted Computing Base. This means IMA will measure all @@ -1726,6 +1745,14 @@ of a GICv2 controller even if the memory range exposed by the device tree is too small. + irqchip.gicv3_nolpi= + [ARM, ARM64] + Force the kernel to ignore the availability of + LPIs (and by consequence ITSs). Intended for system + that use the kernel as a bootloader, and thus want + to let secondary kernels in charge of setting up + LPIs. + irqfixup [HW] When an interrupt is not handled search all handlers for it. Intended to get systems with badly broken @@ -1749,6 +1776,17 @@ nohz Disable the tick when a single task runs. + + A residual 1Hz tick is offloaded to workqueues, which you + need to affine to housekeeping through the global + workqueue's affinity configured via the + /sys/devices/virtual/workqueue/cpumask sysfs file, or + by using the 'domain' flag described below. + + NOTE: by default the global workqueue runs on all CPUs, + so to protect individual CPUs the 'cpumask' file has to + be configured manually after bootup. + domain Isolate from the general SMP balancing and scheduling algorithms. Note that performing domain isolation this way @@ -1808,30 +1846,29 @@ keepinitrd [HW,ARM] kernelcore= [KNL,X86,IA-64,PPC] - Format: nn[KMGTPE] | "mirror" - This parameter - specifies the amount of memory usable by the kernel - for non-movable allocations. The requested amount is - spread evenly throughout all nodes in the system. The - remaining memory in each node is used for Movable - pages. In the event, a node is too small to have both - kernelcore and Movable pages, kernelcore pages will - take priority and other nodes will have a larger number - of Movable pages. The Movable zone is used for the - allocation of pages that may be reclaimed or moved - by the page migration subsystem. This means that - HugeTLB pages may not be allocated from this zone. - Note that allocations like PTEs-from-HighMem still - use the HighMem zone if it exists, and the Normal + Format: nn[KMGTPE] | nn% | "mirror" + This parameter specifies the amount of memory usable by + the kernel for non-movable allocations. The requested + amount is spread evenly throughout all nodes in the + system as ZONE_NORMAL. The remaining memory is used for + movable memory in its own zone, ZONE_MOVABLE. In the + event, a node is too small to have both ZONE_NORMAL and + ZONE_MOVABLE, kernelcore memory will take priority and + other nodes will have a larger ZONE_MOVABLE. + + ZONE_MOVABLE is used for the allocation of pages that + may be reclaimed or moved by the page migration + subsystem. Note that allocations like PTEs-from-HighMem + still use the HighMem zone if it exists, and the Normal zone if it does not. - Instead of specifying the amount of memory (nn[KMGTPE]), - you can specify "mirror" option. In case "mirror" + It is possible to specify the exact amount of memory in + the form of "nn[KMGTPE]", a percentage of total system + memory in the form of "nn%", or "mirror". If "mirror" option is specified, mirrored (reliable) memory is used for non-movable allocations and remaining memory is used - for Movable pages. nn[KMGTPE] and "mirror" are exclusive, - so you can NOT specify nn[KMGTPE] and "mirror" at the same - time. + for Movable pages. "nn[KMGTPE]", "nn%", and "mirror" + are exclusive, so you cannot specify multiple forms. kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port. Format: <Controller#>[,poll interval] @@ -1870,6 +1907,9 @@ kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs. Default is 0 (don't ignore, but inject #GP) + kvm.enable_vmware_backdoor=[KVM] Support VMware backdoor PV interface. + Default is false (don't support). + kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit KVM MMU at runtime. Default is 0 (off) @@ -2220,6 +2260,15 @@ The memory region may be marked as e820 type 12 (0xc) and is NVDIMM or ADR memory. + memmap=<size>%<offset>-<oldtype>+<newtype> + [KNL,ACPI] Convert memory within the specified region + from <oldtype> to <newtype>. If "-<oldtype>" is left + out, the whole region will be marked as <newtype>, + even if previously unavailable. If "+<newtype>" is left + out, matching memory will be removed. Types are + specified as e820 types, e.g., 1 = RAM, 2 = reserved, + 3 = ACPI, 12 = PRAM. + memory_corruption_check=0/1 [X86] Some BIOSes seem to corrupt the first 64k of memory when doing things like suspend/resume. @@ -2336,13 +2385,14 @@ mousedev.yres= [MOUSE] Vertical screen resolution, used for devices reporting absolute coordinates, such as tablets - movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter - is similar to kernelcore except it specifies the - amount of memory used for migratable allocations. - If both kernelcore and movablecore is specified, - then kernelcore will be at *least* the specified - value but may be more. If movablecore on its own - is specified, the administrator must be careful + movablecore= [KNL,X86,IA-64,PPC] + Format: nn[KMGTPE] | nn% + This parameter is the complement to kernelcore=, it + specifies the amount of memory used for migratable + allocations. If both kernelcore and movablecore is + specified, then kernelcore will be at *least* the + specified value but may be more. If movablecore on its + own is specified, the administrator must be careful that the amount of memory usable for all allocations is not too small. @@ -2538,6 +2588,9 @@ This is useful when you use a panic=... timeout and need the box quickly up again. + These settings can be accessed at runtime via + the nmi_watchdog and hardlockup_panic sysctls. + netpoll.carrier_timeout= [NET] Specifies amount of time (in seconds) that netpoll should wait for a carrier. By default netpoll @@ -2741,8 +2794,6 @@ norandmaps Don't use address space randomization. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space - noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops - noreplace-smp [X86-32,SMP] Don't replace SMP instructions with UP alternatives @@ -3112,18 +3163,13 @@ force Enable ASPM even on devices that claim not to support it. WARNING: Forcing ASPM on may cause system lockups. - pcie_hp= [PCIE] PCI Express Hotplug driver options: - nomsi Do not use MSI for PCI Express Native Hotplug (this - makes all PCIe ports use INTx for hotplug services). - - pcie_ports= [PCIE] PCIe ports handling: - auto Ask the BIOS whether or not to use native PCIe services - associated with PCIe ports (PME, hot-plug, AER). Use - them only if that is allowed by the BIOS. - native Use native PCIe services associated with PCIe ports - unconditionally. - compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe - ports driver. + pcie_ports= [PCIE] PCIe port services handling: + native Use native PCIe services (PME, AER, DPC, PCIe hotplug) + even if the platform doesn't give the OS permission to + use them. This may cause conflicts if the platform + also tries to use these services. + compat Disable native PCIe services (PME, AER, DPC, PCIe + hotplug). pcie_port_pm= [PCIE] PCIe port power management handling: off Disable power management of all PCIe ports @@ -3696,7 +3742,11 @@ [KNL, SMP] Set scheduler's default relax_domain_level. See Documentation/cgroup-v1/cpusets.txt. - reserve= [KNL,BUGS] Force the kernel to ignore some iomem area + reserve= [KNL,BUGS] Force kernel to ignore I/O ports or memory + Format: <base1>,<size1>[,<base2>,<size2>,...] + Reserve I/O ports or memory so the kernel won't use + them. If <base> is less than 0x10000, the region + is assumed to be I/O ports; otherwise it is memory. reservetop= [X86-32] Format: nn[KMG] @@ -4346,12 +4396,73 @@ usbcore.nousb [USB] Disable the USB subsystem + usbcore.quirks= + [USB] A list of quirk entries to augment the built-in + usb core quirk list. List entries are separated by + commas. Each entry has the form + VendorID:ProductID:Flags. The IDs are 4-digit hex + numbers and Flags is a set of letters. Each letter + will change the built-in quirk; setting it if it is + clear and clearing it if it is set. The letters have + the following meanings: + a = USB_QUIRK_STRING_FETCH_255 (string + descriptors must not be fetched using + a 255-byte read); + b = USB_QUIRK_RESET_RESUME (device can't resume + correctly so reset it instead); + c = USB_QUIRK_NO_SET_INTF (device can't handle + Set-Interface requests); + d = USB_QUIRK_CONFIG_INTF_STRINGS (device can't + handle its Configuration or Interface + strings); + e = USB_QUIRK_RESET (device can't be reset + (e.g morph devices), don't use reset); + f = USB_QUIRK_HONOR_BNUMINTERFACES (device has + more interface descriptions than the + bNumInterfaces count, and can't handle + talking to these interfaces); + g = USB_QUIRK_DELAY_INIT (device needs a pause + during initialization, after we read + the device descriptor); + h = USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL (For + high speed and super speed interrupt + endpoints, the USB 2.0 and USB 3.0 spec + require the interval in microframes (1 + microframe = 125 microseconds) to be + calculated as interval = 2 ^ + (bInterval-1). + Devices with this quirk report their + bInterval as the result of this + calculation instead of the exponent + variable used in the calculation); + i = USB_QUIRK_DEVICE_QUALIFIER (device can't + handle device_qualifier descriptor + requests); + j = USB_QUIRK_IGNORE_REMOTE_WAKEUP (device + generates spurious wakeup, ignore + remote wakeup capability); + k = USB_QUIRK_NO_LPM (device can't handle Link + Power Management); + l = USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL + (Device reports its bInterval as linear + frames instead of the USB 2.0 + calculation); + m = USB_QUIRK_DISCONNECT_SUSPEND (Device needs + to be disconnected before suspend to + prevent spurious wakeup); + n = USB_QUIRK_DELAY_CTRL_MSG (Device needs a + pause after every control message); + Example: quirks=0781:5580:bk,0a5c:5834:gij + usbhid.mousepoll= [USBHID] The interval which mice are to be polled at. usbhid.jspoll= [USBHID] The interval which joysticks are to be polled at. + usbhid.kbpoll= + [USBHID] The interval which keyboards are to be polled at. + usb-storage.delay_use= [UMS] The delay in seconds before a new device is scanned for Logical Units (default 1). |