diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v1/memory.rst | 7 | ||||
| -rw-r--r-- | Documentation/admin-guide/hw-vuln/srso.rst | 24 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 83 | ||||
| -rw-r--r-- | Documentation/admin-guide/pm/intel_idle.rst | 17 | ||||
| -rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 3 |
5 files changed, 122 insertions, 12 deletions
diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 5f502bf68fbc..ff456871bf4b 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -92,6 +92,13 @@ Brief summary of control files. memory.oom_control set/show oom controls. memory.numa_stat show the number of memory usage per numa node + memory.kmem.limit_in_bytes Deprecated knob to set and read the kernel + memory hard limit. Kernel hard limit is not + supported since 5.16. Writing any value to + do file will not have any effect same as if + nokmem kernel parameter was specified. + Kernel memory is still charged and reported + by memory.kmem.usage_in_bytes. memory.kmem.usage_in_bytes show current kernel memory allocation memory.kmem.failcnt show the number of kernel memory usage hits limits diff --git a/Documentation/admin-guide/hw-vuln/srso.rst b/Documentation/admin-guide/hw-vuln/srso.rst index b6cfb51cb0b4..e715bfc09879 100644 --- a/Documentation/admin-guide/hw-vuln/srso.rst +++ b/Documentation/admin-guide/hw-vuln/srso.rst @@ -46,12 +46,22 @@ The possible values in this file are: The processor is not vulnerable - * 'Vulnerable: no microcode': +* 'Vulnerable': + + The processor is vulnerable and no mitigations have been applied. + + * 'Vulnerable: No microcode': The processor is vulnerable, no microcode extending IBPB functionality to address the vulnerability has been applied. - * 'Mitigation: microcode': + * 'Vulnerable: Safe RET, no microcode': + + The "Safe RET" mitigation (see below) has been applied to protect the + kernel, but the IBPB-extending microcode has not been applied. User + space tasks may still be vulnerable. + + * 'Vulnerable: Microcode, no safe RET': Extended IBPB functionality microcode patch has been applied. It does not address User->Kernel and Guest->Host transitions protection but it @@ -72,11 +82,11 @@ The possible values in this file are: (spec_rstack_overflow=microcode) - * 'Mitigation: safe RET': + * 'Mitigation: Safe RET': - Software-only mitigation. It complements the extended IBPB microcode - patch functionality by addressing User->Kernel and Guest->Host - transitions protection. + Combined microcode/software mitigation. It complements the + extended IBPB microcode patch functionality by addressing + User->Kernel and Guest->Host transitions protection. Selected by default or by spec_rstack_overflow=safe-ret @@ -129,7 +139,7 @@ an indrect branch prediction barrier after having applied the required microcode patch for one's system. This mitigation comes also at a performance cost. -Mitigation: safe RET +Mitigation: Safe RET -------------------- The mitigation works by ensuring all RET instructions speculate to diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 0a1731a0f0ef..dca212b6adfb 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1893,6 +1893,12 @@ 0 -- machine default 1 -- force brightness inversion + ia32_emulation= [X86-64] + Format: <bool> + When true, allows loading 32-bit programs and executing 32-bit + syscalls, essentially overriding IA32_EMULATION_DEFAULT_DISABLED at + boot time. When false, unconditionally disables IA32 emulation. + icn= [HW,ISDN] Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] @@ -2913,6 +2919,38 @@ to extract confidential information from the kernel are also disabled. + locktorture.acq_writer_lim= [KNL] + Set the time limit in jiffies for a lock + acquisition. Acquisitions exceeding this limit + will result in a splat once they do complete. + + locktorture.bind_readers= [KNL] + Specify the list of CPUs to which the readers are + to be bound. + + locktorture.bind_writers= [KNL] + Specify the list of CPUs to which the writers are + to be bound. + + locktorture.call_rcu_chains= [KNL] + Specify the number of self-propagating call_rcu() + chains to set up. These are used to ensure that + there is a high probability of an RCU grace period + in progress at any given time. Defaults to 0, + which disables these call_rcu() chains. + + locktorture.long_hold= [KNL] + Specify the duration in milliseconds for the + occasional long-duration lock hold time. Defaults + to 100 milliseconds. Select 0 to disable. + + locktorture.nested_locks= [KNL] + Specify the maximum lock nesting depth that + locktorture is to exercise, up to a limit of 8 + (MAX_NESTED_LOCKS). Specify zero to disable. + Note that this parameter is ineffective on types + of locks that do not support nested acquisition. + locktorture.nreaders_stress= [KNL] Set the number of locking read-acquisition kthreads. Defaults to being automatically set based on the @@ -2928,6 +2966,25 @@ Set time (s) between CPU-hotplug operations, or zero to disable CPU-hotplug testing. + locktorture.rt_boost= [KNL] + Do periodic testing of real-time lock priority + boosting. Select 0 to disable, 1 to boost + only rt_mutex, and 2 to boost unconditionally. + Defaults to 2, which might seem to be an + odd choice, but which should be harmless for + non-real-time spinlocks, due to their disabling + of preemption. Note that non-realtime mutexes + disable boosting. + + locktorture.rt_boost_factor= [KNL] + Number that determines how often and for how + long priority boosting is exercised. This is + scaled down by the number of writers, so that the + number of boosts per unit time remains roughly + constant as the number of writers increases. + On the other hand, the duration of each boost + increases with the number of writers. + locktorture.shuffle_interval= [KNL] Set task-shuffle interval (jiffies). Shuffling tasks allows some CPUs to go into dyntick-idle @@ -2950,13 +3007,13 @@ locktorture.torture_type= [KNL] Specify the locking implementation to test. + locktorture.verbose= [KNL] + Enable additional printk() statements. + locktorture.writer_fifo= [KNL] Run the write-side locktorture kthreads at sched_set_fifo() real-time priority. - locktorture.verbose= [KNL] - Enable additional printk() statements. - logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver Format: <irq> @@ -4769,6 +4826,13 @@ Set maximum number of finished RCU callbacks to process in one batch. + rcutree.do_rcu_barrier= [KNL] + Request a call to rcu_barrier(). This is + throttled so that userspace tests can safely + hammer on the sysfs variable if they so choose. + If triggered before the RCU grace-period machinery + is fully active, this will error out with EAGAIN. + rcutree.dump_tree= [KNL] Dump the structure of the rcu_node combining tree out at early boot. This is used for diagnostic @@ -5422,6 +5486,12 @@ test until boot completes in order to avoid interference. + refscale.lookup_instances= [KNL] + Number of data elements to use for the forms of + SLAB_TYPESAFE_BY_RCU testing. A negative number + is negated and multiplied by nr_cpu_ids, while + zero specifies nr_cpu_ids. + refscale.loops= [KNL] Set the number of loops over the synchronization primitive under test. Increasing this number @@ -5858,6 +5928,13 @@ This feature may be more efficiently disabled using the csdlock_debug- kernel parameter. + smp.panic_on_ipistall= [KNL] + If a csd_lock_timeout extends for more than + the specified number of milliseconds, panic the + system. By default, let CSD-lock acquisition + take as long as they take. Specifying 300,000 + for this value provides a 5-minute timeout. + smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port smsc-ircc2.ircc_sir= [HW] SIR base I/O port diff --git a/Documentation/admin-guide/pm/intel_idle.rst b/Documentation/admin-guide/pm/intel_idle.rst index b799a43da62e..39bd6ecce7de 100644 --- a/Documentation/admin-guide/pm/intel_idle.rst +++ b/Documentation/admin-guide/pm/intel_idle.rst @@ -170,7 +170,7 @@ and ``idle=nomwait``. If any of them is present in the kernel command line, the ``MWAIT`` instruction is not allowed to be used, so the initialization of ``intel_idle`` will fail. -Apart from that there are four module parameters recognized by ``intel_idle`` +Apart from that there are five module parameters recognized by ``intel_idle`` itself that can be set via the kernel command line (they cannot be updated via sysfs, so that is the only way to change their values). @@ -216,6 +216,21 @@ are ignored). The idle states disabled this way can be enabled (on a per-CPU basis) from user space via ``sysfs``. +The ``ibrs_off`` module parameter is a boolean flag (defaults to +false). If set, it is used to control if IBRS (Indirect Branch Restricted +Speculation) should be turned off when the CPU enters an idle state. +This flag does not affect CPUs that use Enhanced IBRS which can remain +on with little performance impact. + +For some CPUs, IBRS will be selected as mitigation for Spectre v2 and Retbleed +security vulnerabilities by default. Leaving the IBRS mode on while idling may +have a performance impact on its sibling CPU. The IBRS mode will be turned off +by default when the CPU enters into a deep idle state, but not in some +shallower ones. Setting the ``ibrs_off`` module parameter will force the IBRS +mode to off when the CPU is in any one of the available idle states. This may +help performance of a sibling CPU at the expense of a slightly higher wakeup +latency for the idle CPU. + .. _intel-idle-core-and-package-idle-states: diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index cf33de56da27..d89ac2bd8dc4 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -1182,7 +1182,8 @@ automatically on platforms where it can run (that is, platforms with asymmetric CPU topologies and having an Energy Model available). If your platform happens to meet the requirements for EAS but you do not want to use it, change -this value to 0. +this value to 0. On Non-EAS platforms, write operation fails and +read doesn't return anything. task_delayacct =============== |