Documentation: kernel-parameters: sort all "no..." parameters

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Documentation/admin-guide/kernel-parameters.txt

··· 929 929 930 930 debug_objects [KNL] Enable object debugging 931 931 932 - no_debug_objects 933 - [KNL] Disable object debugging 934 - 935 932 debug_guardpage_minorder= 936 933 [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this 937 934 parameter allows control of the order of pages that will ··· 3576 3579 no5lvl [X86-64] Disable 5-level paging mode. Forces 3577 3580 kernel to use 4-level paging instead. 3578 3581 3579 - nofsgsbase [X86] Disables FSGSBASE instructions. 3580 - 3581 - no_console_suspend 3582 - [HW] Never suspend the console 3583 - Disable suspending of consoles during suspend and 3584 - hibernate operations. Once disabled, debugging 3585 - messages can reach various consoles while the rest 3586 - of the system is being put to sleep (ie, while 3587 - debugging driver suspend/resume hooks). This may 3588 - not work reliably with all consoles, but is known 3589 - to work with serial and VGA consoles. 3590 - To facilitate more flexible debugging, we also add 3591 - console_suspend, a printk module parameter to control 3592 - it. Users could use console_suspend (usually 3593 - /sys/module/printk/parameters/console_suspend) to 3594 - turn on/off it dynamically. 3595 - 3596 - novmcoredd [KNL,KDUMP] 3597 - Disable device dump. Device dump allows drivers to 3598 - append dump data to vmcore so you can collect driver 3599 - specified debug info. Drivers can append the data 3600 - without any limit and this data is stored in memory, 3601 - so this may cause significant memory stress. Disabling 3602 - device dump can help save memory but the driver debug 3603 - data will be no longer available. This parameter 3604 - is only available when CONFIG_PROC_VMCORE_DEVICE_DUMP 3605 - is set. 3606 - 3607 3582 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien 3608 3583 caches in the slab allocator. Saves per-node memory, 3609 3584 but will impact performance. ··· 3592 3623 3593 3624 nocache [ARM] 3594 3625 3626 + no_console_suspend 3627 + [HW] Never suspend the console 3628 + Disable suspending of consoles during suspend and 3629 + hibernate operations. Once disabled, debugging 3630 + messages can reach various consoles while the rest 3631 + of the system is being put to sleep (ie, while 3632 + debugging driver suspend/resume hooks). This may 3633 + not work reliably with all consoles, but is known 3634 + to work with serial and VGA consoles. 3635 + To facilitate more flexible debugging, we also add 3636 + console_suspend, a printk module parameter to control 3637 + it. Users could use console_suspend (usually 3638 + /sys/module/printk/parameters/console_suspend) to 3639 + turn on/off it dynamically. 3640 + 3641 + no_debug_objects 3642 + [KNL] Disable object debugging 3643 + 3595 3644 nodsp [SH] Disable hardware DSP at boot time. 3596 3645 3597 3646 noefi Disable EFI runtime services support. ··· 3618 3631 3619 3632 noexec [IA-64] 3620 3633 3621 - nosmap [PPC] 3622 - Disable SMAP (Supervisor Mode Access Prevention) 3623 - even if it is supported by processor. 3624 - 3625 - nosmep [PPC64s] 3626 - Disable SMEP (Supervisor Mode Execution Prevention) 3627 - even if it is supported by processor. 3628 - 3629 3634 noexec32 [X86-64] 3630 3635 This affects only 32-bit executables. 3631 3636 noexec32=on: enable non-executable mappings (default) ··· 3625 3646 noexec32=off: disable non-executable mappings 3626 3647 read implies executable mappings 3627 3648 3649 + no_file_caps Tells the kernel not to honor file capabilities. The 3650 + only way then for a file to be executed with privilege 3651 + is to be setuid root or executed by root. 3652 + 3628 3653 nofpu [MIPS,SH] Disable hardware FPU at boot time. 3654 + 3655 + nofsgsbase [X86] Disables FSGSBASE instructions. 3629 3656 3630 3657 nofxsr [BUGS=X86-32] Disables x86 floating point extended 3631 3658 register save and restore. The kernel will only save 3632 3659 legacy floating-point registers on task switch. 3633 - 3634 - nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings. 3635 - 3636 - nohugevmalloc [KNL,X86,PPC,ARM64] Disable kernel huge vmalloc mappings. 3637 - 3638 - nosmt [KNL,S390] Disable symmetric multithreading (SMT). 3639 - Equivalent to smt=1. 3640 - 3641 - [KNL,X86] Disable symmetric multithreading (SMT). 3642 - nosmt=force: Force disable SMT, cannot be undone 3643 - via the sysfs control file. 3644 - 3645 - nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1 3646 - (bounds check bypass). With this option data leaks are 3647 - possible in the system. 3648 - 3649 - nospectre_v2 [X86,PPC_E500,ARM64] Disable all mitigations for 3650 - the Spectre variant 2 (indirect branch prediction) 3651 - vulnerability. System may allow data leaks with this 3652 - option. 3653 - 3654 - nospectre_bhb [ARM64] Disable all mitigations for Spectre-BHB (branch 3655 - history injection) vulnerability. System may allow data leaks 3656 - with this option. 3657 - 3658 - nospec_store_bypass_disable 3659 - [HW] Disable all mitigations for the Speculative Store Bypass vulnerability 3660 - 3661 - no_uaccess_flush 3662 - [PPC] Don't flush the L1-D cache after accessing user data. 3663 - 3664 - noxsave [BUGS=X86] Disables x86 extended register state save 3665 - and restore using xsave. The kernel will fallback to 3666 - enabling legacy floating-point and sse state. 3667 - 3668 - noxsaveopt [X86] Disables xsaveopt used in saving x86 extended 3669 - register states. The kernel will fall back to use 3670 - xsave to save the states. By using this parameter, 3671 - performance of saving the states is degraded because 3672 - xsave doesn't support modified optimization while 3673 - xsaveopt supports it on xsaveopt enabled systems. 3674 - 3675 - noxsaves [X86] Disables xsaves and xrstors used in saving and 3676 - restoring x86 extended register state in compacted 3677 - form of xsave area. The kernel will fall back to use 3678 - xsaveopt and xrstor to save and restore the states 3679 - in standard form of xsave area. By using this 3680 - parameter, xsave area per process might occupy more 3681 - memory on xsaves enabled systems. 3682 - 3683 - nohlt [ARM,ARM64,MICROBLAZE,SH] Forces the kernel to busy wait 3684 - in do_idle() and not use the arch_cpu_idle() 3685 - implementation; requires CONFIG_GENERIC_IDLE_POLL_SETUP 3686 - to be effective. This is useful on platforms where the 3687 - sleep(SH) or wfi(ARM,ARM64) instructions do not work 3688 - correctly or when doing power measurements to evaluate 3689 - the impact of the sleep instructions. This is also 3690 - useful when using JTAG debugger. 3691 - 3692 - no_file_caps Tells the kernel not to honor file capabilities. The 3693 - only way then for a file to be executed with privilege 3694 - is to be setuid root or executed by root. 3695 3660 3696 3661 nohalt [IA-64] Tells the kernel not to use the power saving 3697 3662 function PAL_HALT_LIGHT when idle. This increases ··· 3660 3737 3661 3738 nohibernate [HIBERNATION] Disable hibernation and resume. 3662 3739 3740 + nohlt [ARM,ARM64,MICROBLAZE,SH] Forces the kernel to busy wait 3741 + in do_idle() and not use the arch_cpu_idle() 3742 + implementation; requires CONFIG_GENERIC_IDLE_POLL_SETUP 3743 + to be effective. This is useful on platforms where the 3744 + sleep(SH) or wfi(ARM,ARM64) instructions do not work 3745 + correctly or when doing power measurements to evaluate 3746 + the impact of the sleep instructions. This is also 3747 + useful when using JTAG debugger. 3748 + 3749 + nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings. 3750 + 3751 + nohugevmalloc [KNL,X86,PPC,ARM64] Disable kernel huge vmalloc mappings. 3752 + 3663 3753 nohz= [KNL] Boottime enable/disable dynamic ticks 3664 3754 Valid arguments: on, off 3665 3755 Default: on ··· 3690 3754 Note that this argument takes precedence over 3691 3755 the CONFIG_RCU_NOCB_CPU_DEFAULT_ALL option. 3692 3756 3693 - noiotrap [SH] Disables trapped I/O port accesses. 3694 - 3695 - noirqdebug [X86-32] Disables the code which attempts to detect and 3696 - disable unhandled interrupt sources. 3697 - 3698 - no_timer_check [X86,APIC] Disables the code which tests for 3699 - broken timer IRQ sources. 3700 - 3701 - noisapnp [ISAPNP] Disables ISA PnP code. 3702 - 3703 3757 noinitrd [RAM] Tells the kernel not to load any configured 3704 3758 initial RAM disk. 3705 3759 ··· 3701 3775 3702 3776 noinvpcid [X86] Disable the INVPCID cpu feature. 3703 3777 3778 + noiotrap [SH] Disables trapped I/O port accesses. 3779 + 3780 + noirqdebug [X86-32] Disables the code which attempts to detect and 3781 + disable unhandled interrupt sources. 3782 + 3783 + noisapnp [ISAPNP] Disables ISA PnP code. 3784 + 3704 3785 nojitter [IA-64] Disables jitter checking for ITC timers. 3705 3786 3706 3787 nokaslr [KNL] ··· 3715 3782 kernel and module base offset ASLR (Address Space 3716 3783 Layout Randomization). 3717 3784 3718 - no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver 3719 - 3720 3785 no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page 3721 3786 fault handling. 3722 3787 3723 - no-vmw-sched-clock 3724 - [X86,PV_OPS] Disable paravirtualized VMware scheduler 3725 - clock and use the default one. 3726 - 3727 - no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES] Disable paravirtualized 3728 - steal time accounting. steal time is computed, but 3729 - won't influence scheduler behaviour 3788 + no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver 3730 3789 3731 3790 nolapic [X86-32,APIC] Do not enable or use the local APIC. 3732 3791 ··· 3730 3805 3731 3806 nomfgpt [X86-32] Disable Multi-Function General Purpose 3732 3807 Timer usage (for AMD Geode machines). 3733 - 3734 - nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to 3735 - shutdown the other cpus. Instead use the REBOOT_VECTOR 3736 - irq. 3737 3808 3738 3809 nomodeset Disable kernel modesetting. Most systems' firmware 3739 3810 sets up a display mode and provides framebuffer memory ··· 3743 3822 3744 3823 nomodule Disable module load 3745 3824 3825 + nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to 3826 + shutdown the other cpus. Instead use the REBOOT_VECTOR 3827 + irq. 3828 + 3746 3829 nopat [X86] Disable PAT (page attribute table extension of 3747 3830 pagetables) support. 3748 3831 ··· 3754 3829 3755 3830 nopku [X86] Disable Memory Protection Keys CPU feature found 3756 3831 in some Intel CPUs. 3832 + 3833 + nopti [X86-64] 3834 + Equivalent to pti=off 3757 3835 3758 3836 nopv= [X86,XEN,KVM,HYPER_V,VMWARE] 3759 3837 Disables the PV optimizations forcing the guest to run ··· 3777 3849 noresume [SWSUSP] Disables resume and restores original swap 3778 3850 space. 3779 3851 3852 + nosbagart [IA-64] 3853 + 3780 3854 no-scroll [VGA] Disables scrollback. 3781 3855 This is required for the Braillex ib80-piezo Braille 3782 3856 reader made by F.H. Papenmeier (Germany). 3783 3857 3784 - nosbagart [IA-64] 3785 - 3786 3858 nosgx [X86-64,SGX] Disables Intel SGX kernel support. 3859 + 3860 + nosmap [PPC] 3861 + Disable SMAP (Supervisor Mode Access Prevention) 3862 + even if it is supported by processor. 3863 + 3864 + nosmep [PPC64s] 3865 + Disable SMEP (Supervisor Mode Execution Prevention) 3866 + even if it is supported by processor. 3787 3867 3788 3868 nosmp [SMP] Tells an SMP kernel to act as a UP kernel, 3789 3869 and disable the IO APIC. legacy for "maxcpus=0". 3790 3870 3871 + nosmt [KNL,S390] Disable symmetric multithreading (SMT). 3872 + Equivalent to smt=1. 3873 + 3874 + [KNL,X86] Disable symmetric multithreading (SMT). 3875 + nosmt=force: Force disable SMT, cannot be undone 3876 + via the sysfs control file. 3877 + 3791 3878 nosoftlockup [KNL] Disable the soft-lockup detector. 3792 3879 3880 + nospec_store_bypass_disable 3881 + [HW] Disable all mitigations for the Speculative Store Bypass vulnerability 3882 + 3883 + nospectre_bhb [ARM64] Disable all mitigations for Spectre-BHB (branch 3884 + history injection) vulnerability. System may allow data leaks 3885 + with this option. 3886 + 3887 + nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1 3888 + (bounds check bypass). With this option data leaks are 3889 + possible in the system. 3890 + 3891 + nospectre_v2 [X86,PPC_E500,ARM64] Disable all mitigations for 3892 + the Spectre variant 2 (indirect branch prediction) 3893 + vulnerability. System may allow data leaks with this 3894 + option. 3895 + 3896 + no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES] Disable paravirtualized 3897 + steal time accounting. steal time is computed, but 3898 + won't influence scheduler behaviour 3899 + 3793 3900 nosync [HW,M68K] Disables sync negotiation for all devices. 3901 + 3902 + no_timer_check [X86,APIC] Disables the code which tests for 3903 + broken timer IRQ sources. 3904 + 3905 + no_uaccess_flush 3906 + [PPC] Don't flush the L1-D cache after accessing user data. 3907 + 3908 + novmcoredd [KNL,KDUMP] 3909 + Disable device dump. Device dump allows drivers to 3910 + append dump data to vmcore so you can collect driver 3911 + specified debug info. Drivers can append the data 3912 + without any limit and this data is stored in memory, 3913 + so this may cause significant memory stress. Disabling 3914 + device dump can help save memory but the driver debug 3915 + data will be no longer available. This parameter 3916 + is only available when CONFIG_PROC_VMCORE_DEVICE_DUMP 3917 + is set. 3918 + 3919 + no-vmw-sched-clock 3920 + [X86,PV_OPS] Disable paravirtualized VMware scheduler 3921 + clock and use the default one. 3794 3922 3795 3923 nowatchdog [KNL] Disable both lockup detectors, i.e. 3796 3924 soft-lockup and NMI watchdog (hard-lockup). ··· 3858 3874 NOTE: this parameter will be ignored on systems with the 3859 3875 LEGACY_XAPIC_DISABLED bit set in the 3860 3876 IA32_XAPIC_DISABLE_STATUS MSR. 3877 + 3878 + noxsave [BUGS=X86] Disables x86 extended register state save 3879 + and restore using xsave. The kernel will fallback to 3880 + enabling legacy floating-point and sse state. 3881 + 3882 + noxsaveopt [X86] Disables xsaveopt used in saving x86 extended 3883 + register states. The kernel will fall back to use 3884 + xsave to save the states. By using this parameter, 3885 + performance of saving the states is degraded because 3886 + xsave doesn't support modified optimization while 3887 + xsaveopt supports it on xsaveopt enabled systems. 3888 + 3889 + noxsaves [X86] Disables xsaves and xrstors used in saving and 3890 + restoring x86 extended register state in compacted 3891 + form of xsave area. The kernel will fall back to use 3892 + xsaveopt and xrstor to save and restore the states 3893 + in standard form of xsave area. By using this 3894 + parameter, xsave area per process might occupy more 3895 + memory on xsaves enabled systems. 3861 3896 3862 3897 nps_mtm_hs_ctr= [KNL,ARC] 3863 3898 This parameter sets the maximum duration, in ··· 4584 4581 vulnerable to issues that PTI mitigates 4585 4582 4586 4583 Not specifying this option is equivalent to pti=auto. 4587 - 4588 - nopti [X86-64] 4589 - Equivalent to pti=off 4590 4584 4591 4585 pty.legacy_count= 4592 4586 [KNL] Number of legacy pty's. Overwrites compiled-in

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