embedded devices based on command line input.
See Documentation/block/cmdline-partition.txt
+ boot_cpus= [SMP]
+ Rather than attempting to online all possible CPUs at
+ boot time, only online the specified set of CPUs.
+
boot_delay= Milliseconds to delay each printk during boot.
Values larger than 10 seconds (10000) are changed to
no delay (0).
seconds. Defaults to 10*60 = 10mins. A value of 0
disables the blank timer.
+ core_ctl_disable_cpumask= [SMP]
+ Exempt the CPUs from being managed by core_ctl.
+ core_ctl operates on a cluster basis. So all the
+ CPUs in a given cluster must be specified to disable
+ core_ctl for that cluster.
+
coredump_filter=
[KNL] Change the default value for
/proc/<pid>/coredump_filter.
The filter can be disabled or changed to another
driver later using sysfs.
- drm_kms_helper.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]
+ drm.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]
Broken monitors, graphic adapters, KVMs and EDIDless
panels may send no or incorrect EDID data sets.
This parameter allows to specify an EDID data sets
improves system performance, but it may also
expose users to several CPU vulnerabilities.
Equivalent to: nopti [X86]
+ nospectre_v1 [X86]
nospectre_v2 [X86]
spectre_v2_user=off [X86]
spec_store_bypass_disable=off [X86]
mds=off [X86]
+ tsx_async_abort=off [X86]
auto (default)
Mitigate all CPU vulnerabilities, but leave SMT
nohugeiomap [KNL,x86] Disable kernel huge I/O mappings.
- nospectre_v1 [PPC] Disable mitigations for Spectre Variant 1 (bounds
- check bypass). With this option data leaks are possible
- in the system.
+ 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_FSL_BOOK3E] Disable all mitigations for the Spectre variant 2
(indirect branch prediction) vulnerability. System may
we can turn it on.
on: enable the feature
+ page_poison= [KNL] Boot-time parameter changing the state of
+ poisoning on the buddy allocator.
+ off: turn off poisoning
+ on: turn on poisoning
+
panic= [KNL] Kernel behaviour on panic: delay <timeout>
timeout > 0: seconds before rebooting
timeout = 0: wait forever
Run specified binary instead of /init from the ramdisk,
used for early userspace startup. See initrd.
+ rdrand= [X86]
+ force - Override the decision by the kernel to hide the
+ advertisement of RDRAND support (this affects
+ certain AMD processors because of buggy BIOS
+ support, specifically around the suspend/resume
+ path).
+
reboot= [KNL]
Format (x86 or x86_64):
[w[arm] | c[old] | h[ard] | s[oft] | g[pio]] \
platforms where RDTSC is slow and this accounting
can add overhead.
+ tsx= [X86] Control Transactional Synchronization
+ Extensions (TSX) feature in Intel processors that
+ support TSX control.
+
+ This parameter controls the TSX feature. The options are:
+
+ on - Enable TSX on the system. Although there are
+ mitigations for all known security vulnerabilities,
+ TSX has been known to be an accelerator for
+ several previous speculation-related CVEs, and
+ so there may be unknown security risks associated
+ with leaving it enabled.
+
+ off - Disable TSX on the system. (Note that this
+ option takes effect only on newer CPUs which are
+ not vulnerable to MDS, i.e., have
+ MSR_IA32_ARCH_CAPABILITIES.MDS_NO=1 and which get
+ the new IA32_TSX_CTRL MSR through a microcode
+ update. This new MSR allows for the reliable
+ deactivation of the TSX functionality.)
+
+ auto - Disable TSX if X86_BUG_TAA is present,
+ otherwise enable TSX on the system.
+
+ Not specifying this option is equivalent to tsx=off.
+
+ See Documentation/hw-vuln/tsx_async_abort.rst
+ for more details.
+
+ tsx_async_abort= [X86,INTEL] Control mitigation for the TSX Async
+ Abort (TAA) vulnerability.
+
+ Similar to Micro-architectural Data Sampling (MDS)
+ certain CPUs that support Transactional
+ Synchronization Extensions (TSX) are vulnerable to an
+ exploit against CPU internal buffers which can forward
+ information to a disclosure gadget under certain
+ conditions.
+
+ In vulnerable processors, the speculatively forwarded
+ data can be used in a cache side channel attack, to
+ access data to which the attacker does not have direct
+ access.
+
+ This parameter controls the TAA mitigation. The
+ options are:
+
+ full - Enable TAA mitigation on vulnerable CPUs
+ if TSX is enabled.
+
+ off - Unconditionally disable TAA mitigation
+
+ Not specifying this option is equivalent to
+ tsx_async_abort=full. On CPUs which are MDS affected
+ and deploy MDS mitigation, TAA mitigation is not
+ required and doesn't provide any additional
+ mitigation.
+
+ For details see:
+ Documentation/hw-vuln/tsx_async_abort.rst
+
turbografx.map[2|3]= [HW,JOY]
TurboGraFX parallel port interface
Format:
or other driver-specific files in the
Documentation/watchdog/ directory.
+ workqueue.watchdog_thresh=
+ If CONFIG_WQ_WATCHDOG is configured, workqueue can
+ warn stall conditions and dump internal state to
+ help debugging. 0 disables workqueue stall
+ detection; otherwise, it's the stall threshold
+ duration in seconds. The default value is 30 and
+ it can be updated at runtime by writing to the
+ corresponding sysfs file.
+
workqueue.disable_numa
By default, all work items queued to unbound
workqueues are affine to the NUMA nodes they're