diff options
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 142 |
1 files changed, 111 insertions, 31 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 19f4423e70d9..b799bcf67d7b 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -331,7 +331,7 @@ APC and your system crashes randomly. apic= [APIC,X86] Advanced Programmable Interrupt Controller - Change the output verbosity whilst booting + Change the output verbosity while booting Format: { quiet (default) | verbose | debug } Change the amount of debugging information output when initialising the APIC and IO-APIC components. @@ -486,10 +486,14 @@ 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" } + cgroup_no_v1= [KNL] Disable cgroup controllers and named hierarchies in v1 + Format: { { controller | "all" | "named" } + [,{ controller | "all" | "named" }...] } Like cgroup_disable, but only applies to cgroup v1; the blacklisted controllers remain available in cgroup2. + "all" blacklists all controllers and "named" disables + named mounts. Specifying both "all" and "named" disables + all v1 hierarchies. cgroup.memory= [KNL] Pass options to the cgroup memory controller. Format: <string> @@ -674,6 +678,9 @@ cpuidle.off=1 [CPU_IDLE] disable the cpuidle sub-system + cpuidle.governor= + [CPU_IDLE] Name of the cpuidle governor to use. + cpufreq.off=1 [CPU_FREQ] disable the cpufreq sub-system @@ -856,7 +863,8 @@ causing system reset or hang due to sending INIT from AP to BSP. - disable_counter_freezing [HW] + perf_v4_pmi= [X86,INTEL] + Format: <bool> Disable Intel PMU counter freezing feature. The feature only exists starting from Arch Perfmon v4 (Skylake and newer). @@ -1020,6 +1028,12 @@ specified address. The serial port must already be setup and configured. Options are not yet supported. + rda,<addr> + Start an early, polled-mode console on a serial port + of an RDA Micro SoC, such as RDA8810PL, at the + specified address. The serial port must already be + setup and configured. Options are not yet supported. + smh Use ARM semihosting calls for early console. s3c2410,<addr> @@ -1682,12 +1696,12 @@ By default, super page will be supported if Intel IOMMU has the capability. With this option, super page will not be supported. - ecs_off [Default Off] - By default, extended context tables will be supported if - the hardware advertises that it has support both for the - extended tables themselves, and also PASID support. With - this option set, extended tables will not be used even - on hardware which claims to support them. + sm_off [Default Off] + By default, scalable mode will be supported if the + hardware advertises that it has support for the scalable + mode translation. With this option set, scalable mode + will not be used even on hardware which claims to support + it. tboot_noforce [Default Off] Do not force the Intel IOMMU enabled under tboot. By default, tboot will force Intel IOMMU on, which @@ -2095,6 +2109,9 @@ off Disables hypervisor mitigations and doesn't emit any warnings. + It also drops the swap size and available + RAM limit restriction on both hypervisor and + bare metal. Default is 'flush'. @@ -2826,7 +2843,7 @@ check bypass). With this option data leaks are possible in the system. - nospectre_v2 [X86] Disable all mitigations for the Spectre variant 2 + nospectre_v2 [X86,PPC_FSL_BOOK3E] Disable all mitigations for the Spectre variant 2 (indirect branch prediction) vulnerability. System may allow data leaks with this option, which is equivalent to spectre_v2=off. @@ -3081,6 +3098,14 @@ timeout < 0: reboot immediately Format: <timeout> + panic_print= Bitmask for printing system info when panic happens. + User can chose combination of the following bits: + bit 0: print all tasks info + bit 1: print system memory info + bit 2: print timer info + bit 3: print locks info if CONFIG_LOCKDEP is on + bit 4: print ftrace buffer + panic_on_warn panic() instead of WARN(). Useful to cause kdump on a WARN(). @@ -3504,6 +3529,10 @@ before loading. See Documentation/blockdev/ramdisk.txt. + psi= [KNL] Enable or disable pressure stall information + tracking. + Format: <bool> + psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to probe for; one of (bare|imps|exps|lifebook|any). psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports @@ -3743,24 +3772,6 @@ in microseconds. The default of zero says no holdoff. - rcutorture.cbflood_inter_holdoff= [KNL] - Set holdoff time (jiffies) between successive - callback-flood tests. - - rcutorture.cbflood_intra_holdoff= [KNL] - Set holdoff time (jiffies) between successive - bursts of callbacks within a given callback-flood - test. - - rcutorture.cbflood_n_burst= [KNL] - Set the number of bursts making up a given - callback-flood test. Set this to zero to - disable callback-flood testing. - - rcutorture.cbflood_n_per_burst= [KNL] - Set the number of callbacks to be registered - in a given burst of a callback-flood test. - rcutorture.fqs_duration= [KNL] Set duration of force_quiescent_state bursts in microseconds. @@ -3773,6 +3784,23 @@ Set wait time between force_quiescent_state bursts in seconds. + rcutorture.fwd_progress= [KNL] + Enable RCU grace-period forward-progress testing + for the types of RCU supporting this notion. + + rcutorture.fwd_progress_div= [KNL] + Specify the fraction of a CPU-stall-warning + period to do tight-loop forward-progress testing. + + rcutorture.fwd_progress_holdoff= [KNL] + Number of seconds to wait between successive + forward-progress tests. + + rcutorture.fwd_progress_need_resched= [KNL] + Enclose cond_resched() calls within checks for + need_resched() during tight-loop forward-progress + testing. + rcutorture.gp_cond= [KNL] Use conditional/asynchronous update-side primitives, if available. @@ -4194,9 +4222,13 @@ spectre_v2= [X86] Control mitigation of Spectre variant 2 (indirect branch speculation) vulnerability. + The default operation protects the kernel from + user space attacks. - on - unconditionally enable - off - unconditionally disable + on - unconditionally enable, implies + spectre_v2_user=on + off - unconditionally disable, implies + spectre_v2_user=off auto - kernel detects whether your CPU model is vulnerable @@ -4206,6 +4238,12 @@ CONFIG_RETPOLINE configuration option, and the compiler with which the kernel was built. + Selecting 'on' will also enable the mitigation + against user space to user space task attacks. + + Selecting 'off' will disable both the kernel and + the user space protections. + Specific mitigations can also be selected manually: retpoline - replace indirect branches @@ -4215,6 +4253,48 @@ Not specifying this option is equivalent to spectre_v2=auto. + spectre_v2_user= + [X86] Control mitigation of Spectre variant 2 + (indirect branch speculation) vulnerability between + user space tasks + + on - Unconditionally enable mitigations. Is + enforced by spectre_v2=on + + off - Unconditionally disable mitigations. Is + enforced by spectre_v2=off + + prctl - Indirect branch speculation is enabled, + but mitigation can be enabled via prctl + per thread. The mitigation control state + is inherited on fork. + + prctl,ibpb + - Like "prctl" above, but only STIBP is + controlled per thread. IBPB is issued + always when switching between different user + space processes. + + seccomp + - Same as "prctl" above, but all seccomp + threads will enable the mitigation unless + they explicitly opt out. + + seccomp,ibpb + - Like "seccomp" above, but only STIBP is + controlled per thread. IBPB is issued + always when switching between different + user space processes. + + auto - Kernel selects the mitigation depending on + the available CPU features and vulnerability. + + Default mitigation: + If CONFIG_SECCOMP=y then "seccomp", otherwise "prctl" + + Not specifying this option is equivalent to + spectre_v2_user=auto. + spec_store_bypass_disable= [HW] Control Speculative Store Bypass (SSB) Disable mitigation (Speculative Store Bypass vulnerability) |