autoconf= [IPV6]
See Documentation/networking/ipv6.rst.
- show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
- Limit apic dumping. The parameter defines the maximal
- number of local apics being dumped. Also it is possible
- to set it to "all" by meaning -- no limit here.
- Format: { 1 (default) | 2 | ... | all }.
- The parameter valid if only apic=debug or
- apic=verbose is specified.
- Example: apic=debug show_lapic=all
-
apm= [APM] Advanced Power Management
See header of arch/x86/kernel/apm_32.c.
+ apparmor= [APPARMOR] Disable or enable AppArmor at boot time
+ Format: { "0" | "1" }
+ See security/apparmor/Kconfig help text
+ 0 -- disable.
+ 1 -- enable.
+ Default value is set via kernel config option.
+
arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
Format: <io>,<irq>,<nodeID>
See Documentation/block/cmdline-partition.rst
boot_delay= Milliseconds to delay each printk during boot.
- Values larger than 10 seconds (10000) are changed to
- no delay (0).
+ Only works if CONFIG_BOOT_PRINTK_DELAY is enabled,
+ and you may also have to specify "lpj=". Boot_delay
+ values larger than 10 seconds (10000) are assumed
+ erroneous and ignored.
Format: integer
bootconfig [KNL]
Format: <string>
nosocket -- Disable socket memory accounting.
nokmem -- Disable kernel memory accounting.
+ nobpf -- Disable BPF memory accounting.
checkreqprot= [SELINUX] Set initial checkreqprot flag value.
Format: { "0" | "1" }
Sets the size of kernel per-numa memory area for
contiguous memory allocations. A value of 0 disables
per-numa CMA altogether. And If this option is not
- specificed, the default value is 0.
+ specified, the default value is 0.
With per-numa CMA enabled, DMA users on node nid will
first try to allocate buffer from the pernuma area
which is located in node nid, if the allocation fails,
driver code when a CPU writes to (or reads from) a
random memory location. Note that there exists a class
of memory corruptions problems caused by buggy H/W or
- F/W or by drivers badly programing DMA (basically when
+ F/W or by drivers badly programming DMA (basically when
memory is written at bus level and the CPU MMU is
bypassed) which are not detectable by
CONFIG_DEBUG_PAGEALLOC, hence this option will not help
can be useful when debugging issues that require an SLB
miss to occur.
- stress_slb [PPC]
- Limits the number of kernel SLB entries, and flushes
- them frequently to increase the rate of SLB faults
- on kernel addresses.
-
- stress_hpt [PPC]
- Limits the number of kernel HPT entries in the hash
- page table to increase the rate of hash page table
- faults on kernel addresses.
-
disable= [IPV6]
See Documentation/networking/ipv6.rst.
disable_radix [PPC]
Disable RADIX MMU mode on POWER9
- radix_hcall_invalidate=on [PPC/PSERIES]
- Disable RADIX GTSE feature and use hcall for TLB
- invalidate.
-
disable_tlbie [PPC]
Disable TLBIE instruction. Currently does not work
with KVM, with HASH MMU, or with coherent accelerators.
Documentation/admin-guide/dynamic-debug-howto.rst
for details.
- nopku [X86] Disable Memory Protection Keys CPU feature found
- in some Intel CPUs.
-
- <module>.async_probe[=<bool>] [KNL]
- If no <bool> value is specified or if the value
- specified is not a valid <bool>, enable asynchronous
- probe on this module. Otherwise, enable/disable
- asynchronous probe on this module as indicated by the
- <bool> value. See also: module.async_probe
-
early_ioremap_debug [KNL]
Enable debug messages in early_ioremap support. This
is useful for tracking down temporary early mappings
specified, the serial port must already be setup and
configured.
- uart[8250],io,<addr>[,options]
- uart[8250],mmio,<addr>[,options]
- uart[8250],mmio32,<addr>[,options]
- uart[8250],mmio32be,<addr>[,options]
+ uart[8250],io,<addr>[,options[,uartclk]]
+ uart[8250],mmio,<addr>[,options[,uartclk]]
+ uart[8250],mmio32,<addr>[,options[,uartclk]]
+ uart[8250],mmio32be,<addr>[,options[,uartclk]]
uart[8250],0x<addr>[,options]
Start an early, polled-mode console on the 8250/16550
UART at the specified I/O port or MMIO address.
If none of [io|mmio|mmio32|mmio32be], <addr> is assumed
to be equivalent to 'mmio'. 'options' are specified
in the same format described for "console=ttyS<n>"; if
- unspecified, the h/w is not initialized.
+ unspecified, the h/w is not initialized. 'uartclk' is
+ the uart clock frequency; if unspecified, it is set
+ to 'BASE_BAUD' * 16.
pl011,<addr>
pl011,mmio32,<addr>
boot up that is likely to be overridden by user space
start up functionality.
+ Optionally, the snapshot can also be defined for a tracing
+ instance that was created by the trace_instance= command
+ line parameter.
+
+ trace_instance=foo,sched_switch ftrace_boot_snapshot=foo
+
+ The above will cause the "foo" tracing instance to trigger
+ a snapshot at the end of boot up.
+
ftrace_dump_on_oops[=orig_cpu]
[FTRACE] will dump the trace buffers on oops.
If no parameter is passed, ftrace will dump
boot-time allocation of gigantic hugepages is skipped.
hugetlb_free_vmemmap=
- [KNL] Reguires CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
+ [KNL] Requires CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
enabled.
Control if HugeTLB Vmemmap Optimization (HVO) is enabled.
Allows heavy hugetlb users to free up some more
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
- between unregistering the boot console and initializing
- the real console.
-
i2c_bus= [HW] Override the default board specific I2C bus speed
or register an additional I2C bus that is not
registered from board initialization code.
js= [HW,JOY] Analog joystick
See Documentation/input/joydev/joystick.rst.
- nokaslr [KNL]
- When CONFIG_RANDOMIZE_BASE is set, this disables
- kernel and module base offset ASLR (Address Space
- Layout Randomization).
-
kasan_multi_shot
[KNL] Enforce KASAN (Kernel Address Sanitizer) to print
report on every invalid memory access. Without this
parameter KASAN will print report only for the first
invalid access.
+ keep_bootcon [KNL]
+ Do not unregister boot console at start. This is only
+ useful for debugging when something happens in the window
+ between unregistering the boot console and initializing
+ the real console.
+
keepinitrd [HW,ARM]
kernelcore= [KNL,X86,IA-64,PPC]
* [no]setxfer: Indicate if transfer speed mode setting
should be skipped.
+ * [no]fua: Disable or enable FUA (Force Unit Access)
+ support for devices supporting this feature.
+
* dump_id: Dump IDENTIFY data.
* disable: Disable this device.
For details see:
Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
+ <module>.async_probe[=<bool>] [KNL]
+ If no <bool> value is specified or if the value
+ specified is not a valid <bool>, enable asynchronous
+ probe on this module. Otherwise, enable/disable
+ asynchronous probe on this module as indicated by the
+ <bool> value. See also: module.async_probe
+
module.async_probe=<bool>
[KNL] When set to true, modules will use async probing
by default. To enable/disable async probing for a
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 evalute
+ correctly or when doing power measurements to evaluate
the impact of the sleep instructions. This is also
useful when using JTAG debugger.
nojitter [IA-64] Disables jitter checking for ITC timers.
+ nokaslr [KNL]
+ When CONFIG_RANDOMIZE_BASE is set, this disables
+ 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
nopcid [X86-64] Disable the PCID cpu feature.
+ nopku [X86] Disable Memory Protection Keys CPU feature found
+ in some Intel CPUs.
+
+ 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
+ XEN HVM, KVM, HYPER_V and VMWARE guest.
+
+ nopvspin [X86,XEN,KVM]
+ Disables the qspinlock slow path using PV optimizations
+ which allow the hypervisor to 'idle' the guest on lock
+ contention.
+
norandmaps Don't use address space randomization. Equivalent to
echo 0 > /proc/sys/kernel/randomize_va_space
pcbit= [HW,ISDN]
- pcd. [PARIDE]
- See header of drivers/block/paride/pcd.c.
- See also Documentation/admin-guide/blockdev/paride.rst.
-
pci=option[,option...] [PCI] various PCI subsystem options.
Some options herein operate on a specific device
for debug and development, but should not be
needed on a platform with proper driver support.
- pd. [PARIDE]
- See Documentation/admin-guide/blockdev/paride.rst.
-
pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
boot time.
Format: { 0 | 1 }
allocator. This parameter is primarily for debugging
and performance comparison.
- pf. [PARIDE]
- See Documentation/admin-guide/blockdev/paride.rst.
-
- pg. [PARIDE]
- See Documentation/admin-guide/blockdev/paride.rst.
-
pirq= [SMP,APIC] Manual mp-table setup
See Documentation/x86/i386/IO-APIC.rst.
pstore.backend= Specify the name of the pstore backend to use
- pt. [PARIDE]
- See Documentation/admin-guide/blockdev/paride.rst.
-
pti= [X86-64] Control Page Table Isolation of user and
kernel address spaces. Disabling this feature
removes hardening, but improves performance of
r128= [HW,DRM]
+ radix_hcall_invalidate=on [PPC/PSERIES]
+ Disable RADIX GTSE feature and use hcall for TLB
+ invalidate.
+
raid= [HW,RAID]
See Documentation/admin-guide/md.rst.
rcupdate.rcu_cpu_stall_timeout to be used (after
conversion from seconds to milliseconds).
+ rcupdate.rcu_cpu_stall_cputime= [KNL]
+ Provide statistics on the cputime and count of
+ interrupts and tasks during the sampling period. For
+ multiple continuous RCU stalls, all sampling periods
+ begin at half of the first RCU stall timeout.
+
+ rcupdate.rcu_exp_stall_task_details= [KNL]
+ Print stack dumps of any tasks blocking the
+ current expedited RCU grace period during an
+ expedited RCU CPU stall warning.
+
rcupdate.rcu_expedited= [KNL]
Use expedited grace-period primitives, for
example, synchronize_rcu_expedited() instead
rdt= [HW,X86,RDT]
Turn on/off individual RDT features. List is:
cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, l2cdp,
- mba.
+ mba, smba, bmec.
E.g. to turn on cmt and turn off mba use:
rdt=cmt,!mba
1 -- enable.
Default value is 1.
- apparmor= [APPARMOR] Disable or enable AppArmor at boot time
- Format: { "0" | "1" }
- See security/apparmor/Kconfig help text
- 0 -- disable.
- 1 -- enable.
- Default value is set via kernel config option.
-
serialnumber [BUGS=X86-32]
sev=option[,option...] [X86-64] See Documentation/x86/x86_64/boot-options.rst
shapers= [NET]
Maximal number of shapers.
+ show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
+ Limit apic dumping. The parameter defines the maximal
+ number of local apics being dumped. Also it is possible
+ to set it to "all" by meaning -- no limit here.
+ Format: { 1 (default) | 2 | ... | all }.
+ The parameter valid if only apic=debug or
+ apic=verbose is specified.
+ Example: apic=debug show_lapic=all
+
simeth= [IA-64]
simscsi=
retpoline,generic - Retpolines
retpoline,lfence - LFENCE; indirect branch
retpoline,amd - alias for retpoline,lfence
- eibrs - enhanced IBRS
- eibrs,retpoline - enhanced IBRS + Retpolines
- eibrs,lfence - enhanced IBRS + LFENCE
+ eibrs - Enhanced/Auto IBRS
+ eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
+ eibrs,lfence - Enhanced/Auto IBRS + LFENCE
ibrs - use IBRS to protect kernel
Not specifying this option is equivalent to
be used to filter out binaries which have
not yet been made aware of AT_MINSIGSTKSZ.
+ stress_hpt [PPC]
+ Limits the number of kernel HPT entries in the hash
+ page table to increase the rate of hash page table
+ faults on kernel addresses.
+
+ stress_slb [PPC]
+ Limits the number of kernel SLB entries, and flushes
+ them frequently to increase the rate of SLB faults
+ on kernel addresses.
+
sunrpc.min_resvport=
sunrpc.max_resvport=
[NFS,SUNRPC]
comma-separated list of trace events to enable. See
also Documentation/trace/events.rst
+ trace_instance=[instance-info]
+ [FTRACE] Create a ring buffer instance early in boot up.
+ This will be listed in:
+
+ /sys/kernel/tracing/instances
+
+ Events can be enabled at the time the instance is created
+ via:
+
+ trace_instance=<name>,<system1>:<event1>,<system2>:<event2>
+
+ Note, the "<system*>:" portion is optional if the event is
+ unique.
+
+ trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall
+
+ will enable the "sched_switch" event (note, the "sched:" is optional, and
+ the same thing would happen if it was left off). The irq_handler_entry
+ event, and all events under the "initcall" system.
+
trace_options=[option-list]
[FTRACE] Enable or disable tracer options at boot.
The option-list is a comma delimited list of options
that can be enabled or disabled just as if you were
to echo the option name into
- /sys/kernel/debug/tracing/trace_options
+ /sys/kernel/tracing/trace_options
For example, to enable stacktrace option (to dump the
stack trace of each event), add to the command line:
[FTRACE] enable this option to disable tracing when a
warning is hit. This turns off "tracing_on". Tracing can
be enabled again by echoing '1' into the "tracing_on"
- file located in /sys/kernel/debug/tracing/
+ file located in /sys/kernel/tracing/
This option is useful, as it disables the trace before
the WARNING dump is called, which prevents the trace to
in situations with strict latency requirements (where
interruptions from clocksource watchdog are not
acceptable).
+ [x86] recalibrate: force recalibration against a HW timer
+ (HPET or PM timer) on systems whose TSC frequency was
+ obtained from HW or FW using either an MSR or CPUID(0x15).
+ Warn if the difference is more than 500 ppm.
+ [x86] watchdog: Use TSC as the watchdog clocksource with
+ which to check other HW timers (HPET or PM timer), but
+ only on systems where TSC has been deemed trustworthy.
+ This will be suppressed by an earlier tsc=nowatchdog and
+ can be overridden by a later tsc=nowatchdog. A console
+ message will flag any such suppression or overriding.
tsc_early_khz= [X86] Skip early TSC calibration and use the given
value instead. Useful when the early TSC frequency discovery
functions are at fixed addresses, they make nice
targets for exploits that can control RIP.
- emulate [default] Vsyscalls turn into traps and are
- emulated reasonably safely. The vsyscall
- page is readable.
+ emulate Vsyscalls turn into traps and are emulated
+ reasonably safely. The vsyscall page is
+ readable.
- xonly Vsyscalls turn into traps and are
+ xonly [default] Vsyscalls turn into traps and are
emulated reasonably safely. The vsyscall
page is not readable.
fairer and the number of possible event channels is
much higher. Default is on (use fifo events).
- 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
- XEN HVM, KVM, HYPER_V and VMWARE guest.
-
- nopvspin [X86,XEN,KVM]
- Disables the qspinlock slow path using PV optimizations
- which allow the hypervisor to 'idle' the guest on lock
- contention.
-
xirc2ps_cs= [NET,PCMCIA]
Format:
<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
management firmware translates the requests into actual
hardware states (core frequency, data fabric and memory
clocks etc.)
+ active
+ Use amd_pstate_epp driver instance as the scaling driver,
+ driver provides a hint to the hardware if software wants
+ to bias toward performance (0x0) or energy efficiency (0xff)
+ to the CPPC firmware. then CPPC power algorithm will
+ calculate the runtime workload and adjust the realtime cores
+ frequency.
git.samba.org / sfrench / cifs-2.6.git / blobdiff