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Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 410 |
1 files changed, 212 insertions, 198 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6221a1d057dd..56efff519454 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -339,6 +339,29 @@ This mode requires kvm-amd.avic=1. (Default when IOMMU HW support is present.) + amd_pstate= [X86] + disable + Do not enable amd_pstate as the default + scaling driver for the supported processors + passive + Use amd_pstate with passive mode as a scaling driver. + In this mode autonomous selection is disabled. + Driver requests a desired performance level and platform + tries to match the same performance level if it is + satisfied by guaranteed performance level. + active + Use amd_pstate_epp driver instance as the scaling driver, + driver provides a hint to the hardware if software wants + to bias toward performance (0x0) or energy efficiency (0xff) + to the CPPC firmware. then CPPC power algorithm will + calculate the runtime workload and adjust the realtime cores + frequency. + guided + Activate guided autonomous mode. Driver requests minimum and + maximum performance level and the platform autonomously + selects a performance level in this range and appropriate + to the current workload. + amijoy.map= [HW,JOY] Amiga joystick support Map of devices attached to JOY0DAT and JOY1DAT Format: <a>,<b> @@ -929,9 +952,6 @@ debug_objects [KNL] Enable object debugging - no_debug_objects - [KNL] Disable object debugging - debug_guardpage_minorder= [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this parameter allows control of the order of pages that will @@ -1582,6 +1602,20 @@ dependencies. This only applies for fw_devlink=on|rpm. Format: <bool> + fw_devlink.sync_state = + [KNL] When all devices that could probe have finished + probing, this parameter controls what to do with + devices that haven't yet received their sync_state() + calls. + Format: { strict | timeout } + strict -- Default. Continue waiting on consumers to + probe successfully. + timeout -- Give up waiting on consumers and call + sync_state() on any devices that haven't yet + received their sync_state() calls after + deferred_probe_timeout has expired or by + late_initcall() if !CONFIG_MODULES. + gamecon.map[2|3]= [HW,JOY] Multisystem joystick and NES/SNES/PSX pad support via parallel port (up to 5 devices per port) @@ -2976,7 +3010,7 @@ mce [X86-32] Machine Check Exception - mce=option [X86-64] See Documentation/x86/x86_64/boot-options.rst + mce=option [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst md= [HW] RAID subsystems devices and level See Documentation/admin-guide/md.rst. @@ -3184,9 +3218,6 @@ deep - Suspend-To-RAM or equivalent (if supported) See Documentation/admin-guide/pm/sleep-states.rst. - meye.*= [HW] Set MotionEye Camera parameters - See Documentation/admin-guide/media/meye.rst. - mfgpt_irq= [IA-32] Specify the IRQ to use for the Multi-Function General Purpose Timers on AMD Geode platforms. @@ -3428,14 +3459,13 @@ 1 to enable accounting Default value is 0. - nfsaddrs= [NFS] Deprecated. Use ip= instead. - See Documentation/admin-guide/nfs/nfsroot.rst. - - nfsroot= [NFS] nfs root filesystem for disk-less boxes. - See Documentation/admin-guide/nfs/nfsroot.rst. + nfs.cache_getent= + [NFS] sets the pathname to the program which is used + to update the NFS client cache entries. - nfsrootdebug [NFS] enable nfsroot debugging messages. - See Documentation/admin-guide/nfs/nfsroot.rst. + nfs.cache_getent_timeout= + [NFS] sets the timeout after which an attempt to + update a cache entry is deemed to have failed. nfs.callback_nr_threads= [NFSv4] set the total number of threads that the @@ -3446,18 +3476,6 @@ [NFS] set the TCP port on which the NFSv4 callback channel should listen. - nfs.cache_getent= - [NFS] sets the pathname to the program which is used - to update the NFS client cache entries. - - nfs.cache_getent_timeout= - [NFS] sets the timeout after which an attempt to - update a cache entry is deemed to have failed. - - nfs.idmap_cache_timeout= - [NFS] set the maximum lifetime for idmapper cache - entries. - nfs.enable_ino64= [NFS] enable 64-bit inode numbers. If zero, the NFS client will fake up a 32-bit inode @@ -3465,6 +3483,10 @@ of returning the full 64-bit number. The default is to return 64-bit inode numbers. + nfs.idmap_cache_timeout= + [NFS] set the maximum lifetime for idmapper cache + entries. + nfs.max_session_cb_slots= [NFSv4.1] Sets the maximum number of session slots the client will assign to the callback @@ -3492,21 +3514,14 @@ will be autodetected by the client, and it will fall back to using the idmapper. To turn off this behaviour, set the value to '0'. + nfs.nfs4_unique_id= [NFS4] Specify an additional fixed unique ident- ification string that NFSv4 clients can insert into their nfs_client_id4 string. This is typically a UUID that is generated at system install time. - nfs.send_implementation_id = - [NFSv4.1] Send client implementation identification - information in exchange_id requests. - If zero, no implementation identification information - will be sent. - The default is to send the implementation identification - information. - - nfs.recover_lost_locks = + nfs.recover_lost_locks= [NFSv4] Attempt to recover locks that were lost due to a lease timeout on the server. Please note that doing this risks data corruption, since there are @@ -3518,7 +3533,15 @@ The default parameter value of '0' causes the kernel not to attempt recovery of lost locks. - nfs4.layoutstats_timer = + nfs.send_implementation_id= + [NFSv4.1] Send client implementation identification + information in exchange_id requests. + If zero, no implementation identification information + will be sent. + The default is to send the implementation identification + information. + + nfs4.layoutstats_timer= [NFSv4.2] Change the rate at which the kernel sends layoutstats to the pNFS metadata server. @@ -3527,12 +3550,19 @@ driver. A non-zero value sets the minimum interval in seconds between layoutstats transmissions. - nfsd.inter_copy_offload_enable = + nfsd.inter_copy_offload_enable= [NFSv4.2] When set to 1, the server will support server-to-server copies for which this server is the destination of the copy. - nfsd.nfsd4_ssc_umount_timeout = + nfsd.nfs4_disable_idmapping= + [NFSv4] When set to the default of '1', the NFSv4 + server will return only numeric uids and gids to + clients using auth_sys, and will accept numeric uids + and gids from such clients. This is intended to ease + migration from NFSv2/v3. + + nfsd.nfsd4_ssc_umount_timeout= [NFSv4.2] When used as the destination of a server-to-server copy, knfsd temporarily mounts the source server. It caches the mount in case @@ -3540,13 +3570,14 @@ used for the number of milliseconds specified by this parameter. - nfsd.nfs4_disable_idmapping= - [NFSv4] When set to the default of '1', the NFSv4 - server will return only numeric uids and gids to - clients using auth_sys, and will accept numeric uids - and gids from such clients. This is intended to ease - migration from NFSv2/v3. + nfsaddrs= [NFS] Deprecated. Use ip= instead. + See Documentation/admin-guide/nfs/nfsroot.rst. + nfsroot= [NFS] nfs root filesystem for disk-less boxes. + See Documentation/admin-guide/nfs/nfsroot.rst. + + nfsrootdebug [NFS] enable nfsroot debugging messages. + See Documentation/admin-guide/nfs/nfsroot.rst. nmi_backtrace.backtrace_idle [KNL] Dump stacks even of idle CPUs in response to an @@ -3579,7 +3610,21 @@ no5lvl [X86-64] Disable 5-level paging mode. Forces kernel to use 4-level paging instead. - nofsgsbase [X86] Disables FSGSBASE instructions. + noaliencache [MM, NUMA, SLAB] Disables the allocation of alien + caches in the slab allocator. Saves per-node memory, + but will impact performance. + + noalign [KNL,ARM] + + noaltinstr [S390] Disables alternative instructions patching + (CPU alternatives feature). + + noapic [SMP,APIC] Tells the kernel to not make use of any + IOAPICs that may be present in the system. + + noautogroup Disable scheduler automatic task group creation. + + nocache [ARM] no_console_suspend [HW] Never suspend the console @@ -3596,32 +3641,8 @@ /sys/module/printk/parameters/console_suspend) to turn on/off it dynamically. - novmcoredd [KNL,KDUMP] - Disable device dump. Device dump allows drivers to - append dump data to vmcore so you can collect driver - specified debug info. Drivers can append the data - without any limit and this data is stored in memory, - so this may cause significant memory stress. Disabling - device dump can help save memory but the driver debug - data will be no longer available. This parameter - is only available when CONFIG_PROC_VMCORE_DEVICE_DUMP - is set. - - noaliencache [MM, NUMA, SLAB] Disables the allocation of alien - caches in the slab allocator. Saves per-node memory, - but will impact performance. - - noalign [KNL,ARM] - - noaltinstr [S390] Disables alternative instructions patching - (CPU alternatives feature). - - noapic [SMP,APIC] Tells the kernel to not make use of any - IOAPICs that may be present in the system. - - noautogroup Disable scheduler automatic task group creation. - - nocache [ARM] + no_debug_objects + [KNL] Disable object debugging nodsp [SH] Disable hardware DSP at boot time. @@ -3631,14 +3652,6 @@ noexec [IA-64] - nosmap [PPC] - Disable SMAP (Supervisor Mode Access Prevention) - even if it is supported by processor. - - nosmep [PPC64s] - Disable SMEP (Supervisor Mode Execution Prevention) - even if it is supported by processor. - noexec32 [X86-64] This affects only 32-bit executables. noexec32=on: enable non-executable mappings (default) @@ -3646,74 +3659,18 @@ noexec32=off: disable non-executable mappings read implies executable mappings + no_file_caps Tells the kernel not to honor file capabilities. The + only way then for a file to be executed with privilege + is to be setuid root or executed by root. + nofpu [MIPS,SH] Disable hardware FPU at boot time. + nofsgsbase [X86] Disables FSGSBASE instructions. + nofxsr [BUGS=X86-32] Disables x86 floating point extended register save and restore. The kernel will only save legacy floating-point registers on task switch. - nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings. - - nohugevmalloc [KNL,X86,PPC,ARM64] Disable kernel huge vmalloc mappings. - - nosmt [KNL,S390] Disable symmetric multithreading (SMT). - Equivalent to smt=1. - - [KNL,X86] Disable symmetric multithreading (SMT). - nosmt=force: Force disable SMT, cannot be undone - via the sysfs control file. - - nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1 - (bounds check bypass). With this option data leaks are - possible in the system. - - nospectre_v2 [X86,PPC_E500,ARM64] Disable all mitigations for - the Spectre variant 2 (indirect branch prediction) - vulnerability. System may allow data leaks with this - option. - - nospectre_bhb [ARM64] Disable all mitigations for Spectre-BHB (branch - history injection) vulnerability. System may allow data leaks - with this option. - - nospec_store_bypass_disable - [HW] Disable all mitigations for the Speculative Store Bypass vulnerability - - no_uaccess_flush - [PPC] Don't flush the L1-D cache after accessing user data. - - 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. - - noxsaveopt [X86] Disables xsaveopt used in saving x86 extended - register states. The kernel will fall back to use - xsave to save the states. By using this parameter, - performance of saving the states is degraded because - xsave doesn't support modified optimization while - xsaveopt supports it on xsaveopt enabled systems. - - noxsaves [X86] Disables xsaves and xrstors used in saving and - restoring x86 extended register state in compacted - form of xsave area. The kernel will fall back to use - xsaveopt and xrstor to save and restore the states - in standard form of xsave area. By using this - parameter, xsave area per process might occupy more - memory on xsaves enabled systems. - - nohlt [ARM,ARM64,MICROBLAZE,SH] Forces the kernel to busy wait - in do_idle() and not use the arch_cpu_idle() - implementation; requires CONFIG_GENERIC_IDLE_POLL_SETUP - to be effective. This is useful on platforms where the - sleep(SH) or wfi(ARM,ARM64) instructions do not work - correctly or when doing power measurements to evaluate - the impact of the sleep instructions. This is also - useful when using JTAG debugger. - - no_file_caps Tells the kernel not to honor file capabilities. The - only way then for a file to be executed with privilege - is to be setuid root or executed by root. - nohalt [IA-64] Tells the kernel not to use the power saving function PAL_HALT_LIGHT when idle. This increases power-consumption. On the positive side, it reduces @@ -3737,6 +3694,19 @@ nohibernate [HIBERNATION] Disable hibernation and resume. + nohlt [ARM,ARM64,MICROBLAZE,SH] Forces the kernel to busy wait + in do_idle() and not use the arch_cpu_idle() + implementation; requires CONFIG_GENERIC_IDLE_POLL_SETUP + to be effective. This is useful on platforms where the + sleep(SH) or wfi(ARM,ARM64) instructions do not work + correctly or when doing power measurements to evaluate + the impact of the sleep instructions. This is also + useful when using JTAG debugger. + + nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings. + + nohugevmalloc [KNL,X86,PPC,ARM64] Disable kernel huge vmalloc mappings. + nohz= [KNL] Boottime enable/disable dynamic ticks Valid arguments: on, off Default: on @@ -3754,16 +3724,6 @@ Note that this argument takes precedence over the CONFIG_RCU_NOCB_CPU_DEFAULT_ALL option. - noiotrap [SH] Disables trapped I/O port accesses. - - noirqdebug [X86-32] Disables the code which attempts to detect and - disable unhandled interrupt sources. - - no_timer_check [X86,APIC] Disables the code which tests for - broken timer IRQ sources. - - noisapnp [ISAPNP] Disables ISA PnP code. - noinitrd [RAM] Tells the kernel not to load any configured initial RAM disk. @@ -3775,6 +3735,13 @@ noinvpcid [X86] Disable the INVPCID cpu feature. + noiotrap [SH] Disables trapped I/O port accesses. + + noirqdebug [X86-32] Disables the code which attempts to detect and + disable unhandled interrupt sources. + + noisapnp [ISAPNP] Disables ISA PnP code. + nojitter [IA-64] Disables jitter checking for ITC timers. nokaslr [KNL] @@ -3782,18 +3749,10 @@ kernel and module base offset ASLR (Address Space Layout Randomization). - no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver - no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page fault handling. - no-vmw-sched-clock - [X86,PV_OPS] Disable paravirtualized VMware scheduler - clock and use the default one. - - no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES] Disable paravirtualized - steal time accounting. steal time is computed, but - won't influence scheduler behaviour + no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver nolapic [X86-32,APIC] Do not enable or use the local APIC. @@ -3806,10 +3765,6 @@ nomfgpt [X86-32] Disable Multi-Function General Purpose Timer usage (for AMD Geode machines). - nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to - shutdown the other cpus. Instead use the REBOOT_VECTOR - irq. - nomodeset Disable kernel modesetting. Most systems' firmware sets up a display mode and provides framebuffer memory for output. With nomodeset, DRM and fbdev drivers will @@ -3822,6 +3777,10 @@ nomodule Disable module load + nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to + shutdown the other cpus. Instead use the REBOOT_VECTOR + irq. + nopat [X86] Disable PAT (page attribute table extension of pagetables) support. @@ -3830,6 +3789,9 @@ nopku [X86] Disable Memory Protection Keys CPU feature found in some Intel CPUs. + nopti [X86-64] + Equivalent to pti=off + nopv= [X86,XEN,KVM,HYPER_V,VMWARE] Disables the PV optimizations forcing the guest to run as generic guest with no PV drivers. Currently support @@ -3849,21 +3811,77 @@ noresume [SWSUSP] Disables resume and restores original swap space. + nosbagart [IA-64] + no-scroll [VGA] Disables scrollback. This is required for the Braillex ib80-piezo Braille reader made by F.H. Papenmeier (Germany). - nosbagart [IA-64] - nosgx [X86-64,SGX] Disables Intel SGX kernel support. + nosmap [PPC] + Disable SMAP (Supervisor Mode Access Prevention) + even if it is supported by processor. + + nosmep [PPC64s] + Disable SMEP (Supervisor Mode Execution Prevention) + even if it is supported by processor. + nosmp [SMP] Tells an SMP kernel to act as a UP kernel, and disable the IO APIC. legacy for "maxcpus=0". + nosmt [KNL,S390] Disable symmetric multithreading (SMT). + Equivalent to smt=1. + + [KNL,X86] Disable symmetric multithreading (SMT). + nosmt=force: Force disable SMT, cannot be undone + via the sysfs control file. + nosoftlockup [KNL] Disable the soft-lockup detector. + nospec_store_bypass_disable + [HW] Disable all mitigations for the Speculative Store Bypass vulnerability + + nospectre_bhb [ARM64] Disable all mitigations for Spectre-BHB (branch + history injection) vulnerability. System may allow data leaks + with this option. + + nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1 + (bounds check bypass). With this option data leaks are + possible in the system. + + nospectre_v2 [X86,PPC_E500,ARM64] Disable all mitigations for + the Spectre variant 2 (indirect branch prediction) + vulnerability. System may allow data leaks with this + option. + + no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES] Disable paravirtualized + steal time accounting. steal time is computed, but + won't influence scheduler behaviour + nosync [HW,M68K] Disables sync negotiation for all devices. + no_timer_check [X86,APIC] Disables the code which tests for + broken timer IRQ sources. + + no_uaccess_flush + [PPC] Don't flush the L1-D cache after accessing user data. + + novmcoredd [KNL,KDUMP] + Disable device dump. Device dump allows drivers to + append dump data to vmcore so you can collect driver + specified debug info. Drivers can append the data + without any limit and this data is stored in memory, + so this may cause significant memory stress. Disabling + device dump can help save memory but the driver debug + data will be no longer available. This parameter + is only available when CONFIG_PROC_VMCORE_DEVICE_DUMP + is set. + + no-vmw-sched-clock + [X86,PV_OPS] Disable paravirtualized VMware scheduler + clock and use the default one. + nowatchdog [KNL] Disable both lockup detectors, i.e. soft-lockup and NMI watchdog (hard-lockup). @@ -3875,6 +3893,25 @@ LEGACY_XAPIC_DISABLED bit set in the IA32_XAPIC_DISABLE_STATUS MSR. + 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. + + noxsaveopt [X86] Disables xsaveopt used in saving x86 extended + register states. The kernel will fall back to use + xsave to save the states. By using this parameter, + performance of saving the states is degraded because + xsave doesn't support modified optimization while + xsaveopt supports it on xsaveopt enabled systems. + + noxsaves [X86] Disables xsaves and xrstors used in saving and + restoring x86 extended register state in compacted + form of xsave area. The kernel will fall back to use + xsaveopt and xrstor to save and restore the states + in standard form of xsave area. By using this + parameter, xsave area per process might occupy more + memory on xsaves enabled systems. + nps_mtm_hs_ctr= [KNL,ARC] This parameter sets the maximum duration, in cycles, each HW thread of the CTOP can run @@ -4410,7 +4447,7 @@ and performance comparison. pirq= [SMP,APIC] Manual mp-table setup - See Documentation/x86/i386/IO-APIC.rst. + See Documentation/arch/x86/i386/IO-APIC.rst. plip= [PPT,NET] Parallel port network link Format: { parport<nr> | timid | 0 } @@ -4582,9 +4619,6 @@ Not specifying this option is equivalent to pti=auto. - nopti [X86-64] - Equivalent to pti=off - pty.legacy_count= [KNL] Number of legacy pty's. Overwrites compiled-in default number. @@ -5591,7 +5625,7 @@ serialnumber [BUGS=X86-32] - sev=option[,option...] [X86-64] See Documentation/x86/x86_64/boot-options.rst + sev=option[,option...] [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst shapers= [NET] Maximal number of shapers. @@ -6130,15 +6164,6 @@ later by a loaded module cannot be set this way. Example: sysctl.vm.swappiness=40 - sysfs.deprecated=0|1 [KNL] - Enable/disable old style sysfs layout for old udev - on older distributions. When this option is enabled - very new udev will not work anymore. When this option - is disabled (or CONFIG_SYSFS_DEPRECATED not compiled) - in older udev will not work anymore. - Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in - the kernel configuration. - sysrq_always_enabled [KNL] Ignore sysrq setting - this boot parameter will @@ -6770,7 +6795,7 @@ Can be used multiple times for multiple devices. vga= [BOOT,X86-32] Select a particular video mode - See Documentation/x86/boot.rst and + See Documentation/arch/x86/boot.rst and Documentation/admin-guide/svga.rst. Use vga=ask for menu. This is actually a boot loader parameter; the value is @@ -6933,6 +6958,12 @@ When enabled, memory and cache locality will be impacted. + writecombine= [LOONGARCH] Control the MAT (Memory Access Type) of + ioremap_wc(). + + on - Enable writecombine, use WUC for ioremap_wc() + off - Disable writecombine, use SUC for ioremap_wc() + x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of default x2apic cluster mode on platforms supporting x2apic. @@ -7059,20 +7090,3 @@ xmon commands. off xmon is disabled. - amd_pstate= [X86] - disable - Do not enable amd_pstate as the default - scaling driver for the supported processors - passive - Use amd_pstate as a scaling driver, driver requests a - desired performance on this abstract scale and the power - management firmware translates the requests into actual - hardware states (core frequency, data fabric and memory - clocks etc.) - active - Use amd_pstate_epp driver instance as the scaling driver, - driver provides a hint to the hardware if software wants - to bias toward performance (0x0) or energy efficiency (0xff) - to the CPPC firmware. then CPPC power algorithm will - calculate the runtime workload and adjust the realtime cores - frequency. |