diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 0aee4110f359..f881d5b13e6c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -929,9 +929,6 @@ 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 @@ -3579,34 +3576,6 @@ no5lvl [X86-64] Disable 5-level paging mode. Forces kernel to use 4-level paging instead. - nofsgsbase [X86] Disables FSGSBASE instructions. - - no_console_suspend - [HW] Never suspend the console - Disable suspending of consoles during suspend and - hibernate operations. Once disabled, debugging - messages can reach various consoles while the rest - of the system is being put to sleep (ie, while - debugging driver suspend/resume hooks). This may - not work reliably with all consoles, but is known - to work with serial and VGA consoles. - To facilitate more flexible debugging, we also add - console_suspend, a printk module parameter to control - it. Users could use console_suspend (usually - /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. @@ -3623,6 +3592,24 @@ nocache [ARM] + no_console_suspend + [HW] Never suspend the console + Disable suspending of consoles during suspend and + hibernate operations. Once disabled, debugging + messages can reach various consoles while the rest + of the system is being put to sleep (ie, while + debugging driver suspend/resume hooks). This may + not work reliably with all consoles, but is known + to work with serial and VGA consoles. + To facilitate more flexible debugging, we also add + console_suspend, a printk module parameter to control + it. Users could use console_suspend (usually + /sys/module/printk/parameters/console_suspend) to + turn on/off it dynamically. + + no_debug_objects + [KNL] Disable object debugging + nodsp [SH] Disable hardware DSP at boot time. noefi Disable EFI runtime services support. @@ -3631,14 +3618,6 @@ 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 +3625,18 @@ 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 +3660,19 @@ 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 +3690,6 @@ 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 +3701,13 @@ 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 +3715,10 @@ 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 +3731,6 @@ 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 +3743,10 @@ 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 +3755,9 @@ 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 +3777,77 @@ 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 +3859,25 @@ 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 @@ -4582,9 +4585,6 @@ 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.