diff options
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 172 |
1 files changed, 155 insertions, 17 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index ecc74fa4bfde..eb0a0582d912 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 @@ -312,6 +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 @@ -542,6 +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> @@ -570,6 +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. @@ -675,6 +690,14 @@ 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/cpufeatures.h for the valid bit @@ -826,6 +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> @@ -905,9 +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 @@ -1039,6 +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 @@ -1164,6 +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. @@ -1661,6 +1709,11 @@ 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) @@ -1767,15 +1820,20 @@ 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] @@ -2141,6 +2199,14 @@ 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 @@ -2254,6 +2320,9 @@ 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 @@ -2538,6 +2607,9 @@ 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. @@ -2744,8 +2816,6 @@ 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 @@ -2921,11 +2991,6 @@ 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 @@ -2959,6 +3024,8 @@ 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, @@ -2977,6 +3044,9 @@ 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 @@ -3008,6 +3078,10 @@ 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). @@ -3111,6 +3185,13 @@ 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) @@ -3284,6 +3365,44 @@ 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. @@ -3517,6 +3636,9 @@ 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 @@ -3695,6 +3817,13 @@ 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> @@ -3748,6 +3877,12 @@ 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 @@ -3908,8 +4043,9 @@ 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. @@ -4077,6 +4213,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. sector if the number is odd); i = IGNORE_DEVICE (don't bind to this device); + j = NO_REPORT_LUNS (don't use report luns + command, uas only); l = NOT_LOCKABLE (don't try to lock and unlock ejectable media); m = MAX_SECTORS_64 (don't transfer more |