Skip to content
Snippets Groups Projects
kernel-parameters.txt 145 KiB
Newer Older
			Controls the behavior of vsyscalls (i.e. calls to
			fixed addresses of 0xffffffffff600x00 from legacy
			code).  Most statically-linked binaries and older
			versions of glibc use these calls.  Because these
			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.
			native      Vsyscalls are native syscall instructions.
			            This is a little bit faster than trapping
			            and makes a few dynamic recompilers work
			            better than they would in emulation mode.
			            It also makes exploits much easier to write.

			none        Vsyscalls don't work at all.  This makes
			            them quite hard to use for exploits but
			            might break your system.

	vt.color=	[VT] Default text color.
			Format: 0xYX, X = foreground, Y = background.
			Default: 0x07 = light gray on black.

	vt.cur_default=	[VT] Default cursor shape.
			Format: 0xCCBBAA, where AA, BB, and CC are the same as
			the parameters of the <Esc>[?A;B;Cc escape sequence;
			see VGA-softcursor.txt. Default: 2 = underline.

	vt.default_blu=	[VT]
			Format: <blue0>,<blue1>,<blue2>,...,<blue15>
			Change the default blue palette of the console.
			This is a 16-member array composed of values
			ranging from 0-255.

	vt.default_grn=	[VT]
			Format: <green0>,<green1>,<green2>,...,<green15>
			Change the default green palette of the console.
			This is a 16-member array composed of values
			ranging from 0-255.

	vt.default_red=	[VT]
			Format: <red0>,<red1>,<red2>,...,<red15>
			Change the default red palette of the console.
			This is a 16-member array composed of values
			ranging from 0-255.

	vt.default_utf8=
			[VT]
			Format=<0|1>
			Set system-wide default UTF-8 mode for all tty's.
			Default is 1, i.e. UTF-8 mode is enabled for all
			newly opened terminals.

	vt.global_cursor_default=
			[VT]
			Format=<-1|0|1>
			Set system-wide default for whether a cursor
			is shown on new VTs. Default is -1,
			i.e. cursors will be created by default unless
			overridden by individual drivers. 0 will hide
			cursors, 1 will display them.

	vt.italic=	[VT] Default color for italic text; 0-15.
			Default: 2 = green.

	vt.underline=	[VT] Default color for underlined text; 0-15.
			Default: 3 = cyan.

	watchdog timers	[HW,WDT] For information on watchdog timers,
			see Documentation/watchdog/watchdog-parameters.txt
			or other driver-specific files in the
			Documentation/watchdog/ directory.
Linus Torvalds's avatar
Linus Torvalds committed

	workqueue.disable_numa
			By default, all work items queued to unbound
			workqueues are affine to the NUMA nodes they're
			issued on, which results in better behavior in
			general.  If NUMA affinity needs to be disabled for
			whatever reason, this option can be used.  Note
			that this also can be controlled per-workqueue for
			workqueues visible under /sys/bus/workqueue/.

	workqueue.power_efficient
			Per-cpu workqueues are generally preferred because
			they show better performance thanks to cache
			locality; unfortunately, per-cpu workqueues tend to
			be more power hungry than unbound workqueues.

			Enabling this makes the per-cpu workqueues which
			were observed to contribute significantly to power
			consumption unbound, leading to measurably lower
			power usage at the cost of small performance
			overhead.

			The default value of this parameter is determined by
			the config option CONFIG_WQ_POWER_EFFICIENT_DEFAULT.

	x2apic_phys	[X86-64,APIC] Use x2apic physical mode instead of
			default x2apic cluster mode on platforms
			supporting x2apic.

	x86_intel_mid_timer= [X86-32,APBT]
			Choose timer option for x86 Intel MID platform.
			Two valid options are apbt timer only and lapic timer
			plus one apbt timer for broadcast timer.
			x86_intel_mid_timer=apbt_only | lapic_and_apbt
	xen_512gb_limit		[KNL,X86-64,XEN]
			Restricts the kernel running paravirtualized under Xen
			to use only up to 512 GB of RAM. The reason to do so is
			crash analysis tools and Xen tools for doing domain
			save/restore/migration must be enabled to handle larger
			domains.

	xen_emul_unplug=		[HW,X86,XEN]
			Unplug Xen emulated devices
			Format: [unplug0,][unplug1]
			ide-disks -- unplug primary master IDE devices
			aux-ide-disks -- unplug non-primary-master IDE devices
			nics -- unplug network devices
			all -- unplug all emulated devices (NICs and IDE disks)
			unnecessary -- unplugging emulated devices is
				unnecessary even if the host did not respond to
				the unplug protocol
			never -- do not unplug even if version check succeeds
	xen_nopvspin	[X86,XEN]
			Disables the ticketlock slowpath using Xen PV
			optimizations.

	xen_nopv	[X86]
			Disables the PV optimizations forcing the HVM guest to
			run as generic HVM guest with no PV drivers.

Linus Torvalds's avatar
Linus Torvalds committed
	xirc2ps_cs=	[NET,PCMCIA]
			Format:
			<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds's avatar
Linus Torvalds committed

______________________________________________________________________
Linus Torvalds's avatar
Linus Torvalds committed

TODO:

	Add more DRM drivers.