causing system reset or hang due to sending
INIT from AP to BSP.
+ disable_counter_freezing [HW]
+ Disable Intel PMU counter freezing feature.
+ The feature only exists starting from
+ Arch Perfmon v4 (Skylake and newer).
+
disable_ddw [PPC/PSERIES]
Disable Dynamic DMA Window support. Use this if
to workaround buggy firmware.
earlyprintk=serial[,0x...[,baudrate]]
earlyprintk=ttySn[,baudrate]
earlyprintk=dbgp[debugController#]
- earlyprintk=pciserial,bus:device.function[,baudrate]
+ earlyprintk=pciserial[,force],bus:device.function[,baudrate]
earlyprintk=xdbc[xhciController#]
earlyprintk is useful when the kernel crashes before
The sclp output can only be used on s390.
+ The optional "force" to "pciserial" enables use of a
+ PCI device even when its classcode is not of the
+ UART class.
+
edac_report= [HW,EDAC] Control how to report EDAC event
Format: {"on" | "off" | "force"}
on: enable EDAC to report H/W event. May be overridden
hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
If specified, z/VM IUCV HVC accepts connections
from listed z/VM user IDs only.
+
+ hv_nopvspin [X86,HYPER_V] Disables the paravirt spinlock optimizations
+ which allow the hypervisor to 'idle' the
+ guest on lock contention.
+
keep_bootcon [KNL]
Do not unregister boot console at start. This is only
useful for debugging when something happens in the window
nobypass [PPC/POWERNV]
Disable IOMMU bypass, using IOMMU for PCI devices.
+ iommu.strict= [ARM64] Configure TLB invalidation behaviour
+ Format: { "0" | "1" }
+ 0 - Lazy mode.
+ Request that DMA unmap operations use deferred
+ invalidation of hardware TLBs, for increased
+ throughput at the cost of reduced device isolation.
+ Will fall back to strict mode if not supported by
+ the relevant IOMMU driver.
+ 1 - Strict mode (default).
+ DMA unmap operations invalidate IOMMU hardware TLBs
+ synchronously.
+
iommu.passthrough=
[ARM64] Configure DMA to bypass the IOMMU by default.
Format: { "0" | "1" }
0 - Use IOMMU translation for DMA.
1 - Bypass the IOMMU for DMA.
- unset - Use IOMMU translation for DMA.
+ unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
io7= [HW] IO7 for Marvel based alpha systems
See comment before marvel_specify_io7 in
ltpc= [NET]
Format: <io>,<irq>,<dma>
+ lsm.debug [SECURITY] Enable LSM initialization debugging output.
+
machvec= [IA-64] Force the use of a particular machine-vector
(machvec) in a generic kernel.
Example: machvec=hpzx1_swiotlb
seconds. Use this parameter to check at some
other rate. 0 disables periodic checking.
- memtest= [KNL,X86,ARM] Enable memtest
+ memtest= [KNL,X86,ARM,PPC] Enable memtest
Format: <integer>
default : 0 <disable>
Specifies the number of memtest passes to be
In kernels built with CONFIG_RCU_NOCB_CPU=y, set
the specified list of CPUs to be no-callback CPUs.
- Invocation of these CPUs' RCU callbacks will
- be offloaded to "rcuox/N" kthreads created for
- that purpose, where "x" is "b" for RCU-bh, "p"
- for RCU-preempt, and "s" for RCU-sched, and "N"
- is the CPU number. This reduces OS jitter on the
- offloaded CPUs, which can be useful for HPC and
- real-time workloads. It can also improve energy
- efficiency for asymmetric multiprocessors.
+ Invocation of these CPUs' RCU callbacks will be
+ offloaded to "rcuox/N" kthreads created for that
+ purpose, where "x" is "p" for RCU-preempt, and
+ "s" for RCU-sched, and "N" is the CPU number.
+ This reduces OS jitter on the offloaded CPUs,
+ which can be useful for HPC and real-time
+ workloads. It can also improve energy efficiency
+ for asymmetric multiprocessors.
rcu_nocb_poll [KNL]
Rather than requiring that offloaded CPUs
Set required age in jiffies for a
given grace period before RCU starts
soliciting quiescent-state help from
- rcu_note_context_switch().
+ rcu_note_context_switch(). If not specified, the
+ kernel will calculate a value based on the most
+ recent settings of rcutree.jiffies_till_first_fqs
+ and rcutree.jiffies_till_next_fqs.
+ This calculated value may be viewed in
+ rcutree.jiffies_to_sched_qs. Any attempt to
+ set rcutree.jiffies_to_sched_qs will be
+ cheerfully overwritten.
rcutree.jiffies_till_first_fqs= [KNL]
Set delay from grace-period initialization to
rcupdate.rcu_self_test= [KNL]
Run the RCU early boot self tests
- rcupdate.rcu_self_test_bh= [KNL]
- Run the RCU bh early boot self tests
-
- rcupdate.rcu_self_test_sched= [KNL]
- Run the RCU sched early boot self tests
-
rdinit= [KNL]
Format: <full_path>
Run specified binary instead of /init from the ramdisk,
usbcore.old_scheme_first=
[USB] Start with the old device initialization
- scheme (default 0 = off).
+ scheme, applies only to low and full-speed devices
+ (default 0 = off).
usbcore.usbfs_memory_mb=
[USB] Memory limit (in MB) for buffers allocated by
This is actually a boot loader parameter; the value is
passed to the kernel using a special protocol.
+ vm_debug[=options] [KNL] Available with CONFIG_DEBUG_VM=y.
+ May slow down system boot speed, especially when
+ enabled on systems with a large amount of memory.
+ All options are enabled by default, and this
+ interface is meant to allow for selectively
+ enabling or disabling specific virtual memory
+ debugging features.
+
+ Available options are:
+ P Enable page structure init time poisoning
+ - Disable all of the above options
+
vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
size of <nn>. This can be used to increase the
minimum size (128MB on x86). It can also be used to
projects / linux / blobdiff