diff options
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 252 |
1 files changed, 226 insertions, 26 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 6a263f154..46726d489 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -131,6 +131,7 @@ parameter is applicable: More X86-64 boot options can be found in Documentation/x86/x86_64/boot-options.txt . X86 Either 32-bit or 64-bit x86 (same as X86-32+X86-64) + X86_UV SGI UV support is enabled. XEN Xen support is enabled In addition, the following text indicates that the option: @@ -167,16 +168,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted. acpi= [HW,ACPI,X86,ARM64] Advanced Configuration and Power Interface - Format: { force | off | strict | noirq | rsdt | + Format: { force | on | off | strict | noirq | rsdt | copy_dsdt } force -- enable ACPI if default was off + on -- enable ACPI but allow fallback to DT [arm64] off -- disable ACPI if default was on noirq -- do not use ACPI for IRQ routing strict -- Be less tolerant of platforms that are not strictly ACPI specification compliant. rsdt -- prefer RSDT over (default) XSDT copy_dsdt -- copy DSDT to memory - For ARM64, ONLY "acpi=off" or "acpi=force" are available + For ARM64, ONLY "acpi=off", "acpi=on" or "acpi=force" + are available See also Documentation/power/runtime_pm.txt, pci=noacpi @@ -193,6 +196,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. (e.g. thinkpad_acpi, sony_acpi, etc.) instead of the ACPI video.ko driver. + acpi_force_32bit_fadt_addr + force FADT to use 32 bit addresses rather than the + 64 bit X_* addresses. Some firmware have broken 64 + bit addresses for force ACPI ignore these and use + the older legacy 32 bit addresses. + acpica_no_return_repair [HW, ACPI] Disable AML predefined validation mechanism This mechanism can repair the evaluation result to make @@ -306,6 +315,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. acpi_osi=!* # remove all strings acpi_osi=! # disable all built-in OS vendor strings + acpi_osi=!! # enable all built-in OS vendor + strings acpi_osi= # disable all strings 'acpi_osi=!' can be used in combination with single or @@ -536,6 +547,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Format: <int> (must be >=0) Default: 64 + bau= [X86_UV] Enable the BAU on SGI UV. The default + behavior is to disable the BAU (i.e. bau=0). + Format: { "0" | "1" } + 0 - Disable the BAU. + 1 - Enable the BAU. + unset - Disable the BAU. + baycom_epp= [HW,AX25] Format: <io>,<mode> @@ -564,6 +582,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. bootmem_debug [KNL] Enable bootmem allocator debug messages. + bert_disable [ACPI] + Disable BERT OS support on buggy BIOSes. + bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) bttv.radio= Most important insmod options are available as kernel args too. @@ -608,6 +629,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. cut the overhead, others just disable the usage. So only cgroup_disable=memory is actually worthy} + cgroup_no_v1= [KNL] Disable one, multiple, all cgroup controllers in v1 + Format: { controller[,controller...] | "all" } + Like cgroup_disable, but only applies to cgroup v1; + the blacklisted controllers remain available in cgroup2. + cgroup.memory= [KNL] Pass options to the cgroup memory controller. Format: <string> nosocket -- Disable socket memory accounting. @@ -664,9 +690,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted. [SPARC64] tick [X86-64] hpet,tsc + clocksource.arm_arch_timer.evtstrm= + [ARM,ARM64] + Format: <bool> + Enable/disable the eventstream feature of the ARM + architected timer so that code using WFE-based polling + loops can be debugged more effectively on production + systems. + clearcpuid=BITNUM [X86] Disable CPUID feature X for the kernel. See - arch/x86/include/asm/cpufeature.h for the valid bit + arch/x86/include/asm/cpufeatures.h for the valid bit numbers. Note the Linux specific bits are not necessarily stable over kernel options, but the vendor specific ones should be. @@ -815,6 +849,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. It will be ignored when crashkernel=X,high is not used or memory reserved is below 4G. + cryptomgr.notests + [KNL] Disable crypto self-tests + cs89x0_dma= [HW,NET] Format: <dma> @@ -894,9 +931,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted. dhash_entries= [KNL] Set number of hash buckets for dentry cache. + disable_1tb_segments [PPC] + Disables the use of 1TB hash page table segments. This + causes the kernel to fall back to 256MB segments which + can be useful when debugging issues that require an SLB + miss to occur. + disable= [IPV6] See Documentation/networking/ipv6.txt. + disable_radix [PPC] + Disable RADIX MMU mode on POWER9 + disable_cpu_apicid= [X86,APIC,SMP] Format: <int> The number of initial APIC ID for the @@ -976,6 +1022,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. See Documentation/x86/intel_mpx.txt for more information about the feature. + nopku [X86] Disable Memory Protection Keys CPU feature found + in some Intel CPUs. + eagerfpu= [X86] on enable eager fpu restore off disable eager fpu restore @@ -1025,6 +1074,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. the driver will use only 32-bit accessors to read/write the device registers. + meson,<addr> + Start an early, polled-mode console on a meson serial + port at the specified address. The serial port must + already be setup and configured. Options are not yet + supported. + msm_serial,<addr> Start an early, polled-mode console on an msm serial port at the specified address. The serial port @@ -1058,6 +1113,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. A valid base address must be provided, and the serial port must already be setup and configured. + armada3700_uart,<addr> + Start an early, polled-mode console on the + Armada 3700 serial port at the specified + address. The serial port must already be setup + and configured. Options are not yet supported. + earlyprintk= [X86,SH,BLACKFIN,ARM,M68k] earlyprintk=vga earlyprintk=efi @@ -1144,6 +1205,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Address Range Mirroring feature even if your box doesn't support it. + efivar_ssdt= [EFI; X86] Name of an EFI variable that contains an SSDT + that is to be dynamically loaded by Linux. If there are + multiple variables with the same name but with different + vendor GUIDs, all of them will be loaded. See + Documentation/acpi/ssdt-overlays.txt for details. + + eisa_irq_edge= [PARISC,HW] See header of drivers/parisc/eisa.c. @@ -1389,7 +1457,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX controllers i8042.notimeout [HW] Ignore timeout condition signalled by controller - i8042.reset [HW] Reset the controller during init and cleanup + i8042.reset [HW] Reset the controller during init, cleanup and + suspend-to-ram transitions, only during s2r + transitions, or never reset + Format: { 1 | Y | y | 0 | N | n } + 1, Y, y: always reset controller + 0, N, n: don't ever reset controller + Default: only on s2r transitions on x86; most other + architectures force reset to be always executed i8042.unlock [HW] Unlock (ignore) the keylock i8042.kbdreset [HW] Reset device connected to KBD port @@ -1641,6 +1716,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. hwp_only Only load intel_pstate on systems which support hardware P state control (HWP) if available. + support_acpi_ppc + Enforce ACPI _PPC performance limits. If the Fixed ACPI + Description Table, specifies preferred power management + profile as "Enterprise Server" or "Performance Server", + then this feature is turned on by default. intremap= [X86-64, Intel-IOMMU] on enable Interrupt Remapping (default) @@ -1687,6 +1767,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted. ip= [IP_PNP] See Documentation/filesystems/nfs/nfsroot.txt. + irqaffinity= [SMP] Set the default irq affinity mask + Format: + <cpu number>,...,<cpu number> + or + <cpu number>-<cpu number> + (must be a positive range in ascending order) + or a mixture + <cpu number>,...,<cpu number>-<cpu number> + irqfixup [HW] When an interrupt is not handled search all handlers for it. Intended to get systems with badly broken @@ -1738,19 +1827,26 @@ bytes respectively. Such letter suffixes can also be entirely omitted. PCI device 00:14.0 write the parameter as: ivrs_hpet[0]=00:14.0 + ivrs_acpihid [HW,X86_64] + Provide an override to the ACPI-HID:UID<->DEVICE-ID + mapping provided in the IVRS ACPI table. For + example, to map UART-HID:UID AMD0020:0 to + PCI device 00:14.5 write the parameter as: + ivrs_acpihid[00:14.5]=AMD0020:0 + js= [HW,JOY] Analog joystick See Documentation/input/joystick.txt. - kaslr/nokaslr [X86] - Enable/disable kernel and module base offset ASLR - (Address Space Layout Randomization) if built into - the kernel. When CONFIG_HIBERNATION is selected, - kASLR is disabled by default. When kASLR is enabled, - hibernation will be disabled. + nokaslr [KNL] + When CONFIG_RANDOMIZE_BASE is set, this disables + kernel and module base offset ASLR (Address Space + Layout Randomization). keepinitrd [HW,ARM] - kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter + 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 @@ -1766,6 +1862,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 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" + 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. + kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port. Format: <Controller#>[,poll interval] The controller # is the number of the ehci usb debug @@ -2102,6 +2206,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted. [KNL,SH] Allow user to override the default size for per-device physically contiguous DMA buffers. + memhp_default_state=online/offline + [KNL] Set the initial state for the memory hotplug + onlining policy. If not specified, the default value is + set according to the + CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE kernel config + option. + See Documentation/memory-hotplug.txt. + memmap=exactmap [KNL,X86] Enable setting of an exact E820 memory map, as specified by the user. Such memmap=exactmap lines can be constructed based on @@ -2215,6 +2327,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Note that if CONFIG_MODULE_SIG_FORCE is set, that is always true, so this option does nothing. + module_blacklist= [KNL] Do not load a comma-separated list of + modules. Useful for debugging problem modules. + mousedev.tap_time= [MOUSE] Maximum time between finger touching and leaving touchpad surface for touch to be considered @@ -2499,6 +2614,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. nohugeiomap [KNL,x86] Disable kernel huge I/O mappings. + nosmt [KNL,S390] Disable symmetric multithreading (SMT). + Equivalent to smt=1. + noxsave [BUGS=X86] Disables x86 extended register state save and restore using xsave. The kernel will fallback to enabling legacy floating-point and sse state. @@ -2566,6 +2684,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. nointroute [IA-64] + noinvpcid [X86] Disable the INVPCID cpu feature. + nojitter [IA-64] Disables jitter checking for ITC timers. no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver @@ -2582,7 +2702,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. nolapic_timer [X86-32,APIC] Do not use the local APIC timer. noltlbs [PPC] Do not use large page/tlb entries for kernel - lowmem mapping on PPC40x. + lowmem mapping on PPC40x and PPC8xx nomca [IA-64] Disable machine check abort handling @@ -2703,8 +2823,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. timer: [X86] Force use of architectural NMI timer mode (see also oprofile.timer for generic hr timer mode) - [s390] Force legacy basic mode sampling - (report cpu_type "timer") oops=panic Always panic on oopses. Default is to just kill the process, but there is a small probability of @@ -2721,6 +2839,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. we can turn it on. on: enable the feature + page_poison= [KNL] Boot-time parameter changing the state of + poisoning on the buddy allocator. + off: turn off poisoning + on: turn on poisoning + panic= [KNL] Kernel behaviour on panic: delay <timeout> timeout > 0: seconds before rebooting timeout = 0: wait forever @@ -2875,11 +2998,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. for broken drivers that don't call it. skip_isa_align [X86] do not align io start addr, so can handle more pci cards - firmware [ARM] Do not re-enumerate the bus but instead - just use the configuration from the - bootloader. This is currently used on - IXP2000 systems where the bus has to be - configured a certain way for adjunct CPUs. noearly [X86] Don't do any early type 1 scanning. This might help on some broken boards which machine check when some devices' config space @@ -2913,12 +3031,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted. resource_alignment= Format: [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...] + [<order of align>@]pci:<vendor>:<device>\ + [:<subvendor>:<subdevice>][; ...] Specifies alignment and device to reassign aligned memory resources. If <order of align> is not specified, PAGE_SIZE is used as alignment. PCI-PCI bridge can be specified, if resource windows need to be expanded. + To specify the alignment for several + instances of a device, the PCI vendor, + device, subvendor, and subdevice may be + specified, e.g., 4096@pci:8086:9c22:103c:198f ecrc= Enable/disable PCIe ECRC (transaction layer end-to-end CRC checking). bios: Use BIOS/firmware settings. This is the @@ -2931,6 +3055,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. hpmemsize=nn[KMG] The fixed amount of bus space which is reserved for hotplug bridge's memory window. Default size is 2 megabytes. + hpbussize=nn The minimum amount of additional bus numbers + reserved for buses below a hotplug bridge. + Default is 1. realloc= Enable/disable reallocating PCI bridge resources if allocations done by BIOS are too small to accommodate resources required by all child @@ -2962,6 +3089,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe ports driver. + pcie_port_pm= [PCIE] PCIe port power management handling: + off Disable power management of all PCIe ports + force Forcibly enable power management of all PCIe ports + pcie_pme= [PCIE,PM] Native PCIe PME signaling options: nomsi Do not use MSI for native PCIe PME signaling (this makes all PCIe root ports use INTx for all services). @@ -3065,6 +3196,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Format: <bool> (1/Y/y=enable, 0/N/n=disable) default: disabled + printk.devkmsg={on,off,ratelimit} + Control writing to /dev/kmsg. + on - unlimited logging to /dev/kmsg from userspace + off - logging to /dev/kmsg disabled + ratelimit - ratelimit the logging + Default: ratelimit + printk.time= Show timing data prefixed to each printk message line Format: <bool> (1/Y/y=enable, 0/N/n=disable) @@ -3238,6 +3376,44 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Lazy RCU callbacks are those which RCU can prove do nothing more than free memory. + rcuperf.gp_exp= [KNL] + Measure performance of expedited synchronous + grace-period primitives. + + rcuperf.holdoff= [KNL] + Set test-start holdoff period. The purpose of + this parameter is to delay the start of the + test until boot completes in order to avoid + interference. + + rcuperf.nreaders= [KNL] + Set number of RCU readers. The value -1 selects + N, where N is the number of CPUs. A value + "n" less than -1 selects N-n+1, where N is again + the number of CPUs. For example, -2 selects N + (the number of CPUs), -3 selects N+1, and so on. + A value of "n" less than or equal to -N selects + a single reader. + + rcuperf.nwriters= [KNL] + Set number of RCU writers. The values operate + the same as for rcuperf.nreaders. + N, where N is the number of CPUs + + rcuperf.perf_runnable= [BOOT] + Start rcuperf running at boot time. + + rcuperf.shutdown= [KNL] + Shut the system down after performance tests + complete. This is useful for hands-off automated + testing. + + rcuperf.perf_type= [KNL] + Specify the RCU implementation to test. + + rcuperf.verbose= [KNL] + Enable additional printk() statements. + rcutorture.cbflood_inter_holdoff= [KNL] Set holdoff time (jiffies) between successive callback-flood tests. @@ -3424,7 +3600,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. relax_domain_level= [KNL, SMP] Set scheduler's default relax_domain_level. - See Documentation/cgroups/cpusets.txt. + See Documentation/cgroup-v1/cpusets.txt. relative_sleep_states= [SUSPEND] Use sleep state labeling where the deepest @@ -3471,6 +3647,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. present during boot. nocompress Don't compress/decompress hibernation images. no Disable hibernation and resume. + protect_image Turn on image protection during restoration + (that will set all pages holding image data + during restoration read-only). retain_initrd [RAM] Keep initrd memory after extraction @@ -3491,6 +3670,16 @@ bytes respectively. Such letter suffixes can also be entirely omitted. ro [KNL] Mount root device read-only on boot + rodata= [KNL] + on Mark read-only kernel memory as read-only (default). + off Leave read-only kernel memory writable for debugging. + + rockchip.usb_uart + Enable the uart passthrough on the designated usb port + on Rockchip SoCs. When active, the signals of the + debug-uart get routed to the D+ and D- pins of the usb + port and the regular usb controller gets disabled. + root= [KNL] Root filesystem See name_to_dev_t comment in init/do_mounts.c. @@ -3639,6 +3828,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 1: Fast pin select (default) 2: ATC IRMode + smt [KNL,S390] Set the maximum number of threads (logical + CPUs) to use per physical CPU on systems capable of + symmetric multithreading (SMT). Will be capped to the + actual hardware limit. + Format: <integer> + Default: -1 (no limit) + softlockup_panic= [KNL] Should the soft-lockup detector generate panics. Format: <integer> @@ -3692,6 +3888,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. using these two parameters to set the minimum and maximum port values. + sunrpc.svc_rpc_per_connection_limit= + [NFS,SUNRPC] + Limit the number of requests that the server will + process in parallel from a single connection. + The default value is 0 (no limit). + sunrpc.pool_mode= [NFS] Control how the NFS server code allocates CPUs to @@ -3727,7 +3929,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. swapaccount=[0|1] [KNL] Enable accounting of swap in memory resource controller if no parameter or 1 is given or disable - it if 0 is given (See Documentation/cgroups/memory.txt) + it if 0 is given (See Documentation/cgroup-v1/memory.txt) swiotlb= [ARM,IA-64,PPC,MIPS,X86] Format: { <int> | force } @@ -3852,8 +4054,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. trace_event=[event-list] [FTRACE] Set and start specified trace events in order - to facilitate early boot debugging. - See also Documentation/trace/events.txt + to facilitate early boot debugging. The event-list is a + comma separated list of trace events to enable. See + also Documentation/trace/events.txt trace_options=[option-list] [FTRACE] Enable or disable tracer options at boot. @@ -4061,9 +4264,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. HIGHMEM regardless of setting of CONFIG_HIGHPTE. - uuid_debug= (Boolean) whether to enable debugging of TuxOnIce's - uuid support. - vdso= [X86,SH] On X86_32, this is an alias for vdso32=. Otherwise: |