Merge branch 'core/speculation' of git://git.kernel.org/pub/scm/linux/kernel/git...
[sfrench/cifs-2.6.git] / Documentation / admin-guide / kernel-parameters.txt
index 1ae93872b79fd8f165dc7564d5a73c6b2d412811..cf82bac648cd909751b4c18350de66393135067f 100644 (file)
                        possible to determine what the correct size should be.
                        This option provides an override for these situations.
 
+       carrier_timeout=
+                       [NET] Specifies amount of time (in seconds) that
+                       the kernel should wait for a network carrier. By default
+                       it waits 120 seconds.
+
        ca_keys=        [KEYS] This parameter identifies a specific key(s) on
                        the system trusted keyring to be used for certificate
                        trust validation.
                        The filter can be disabled or changed to another
                        driver later using sysfs.
 
+       driver_async_probe=  [KNL]
+                       List of driver names to be probed asynchronously.
+                       Format: <driver_name1>,<driver_name2>...
+
        drm.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]
                        Broken monitors, graphic adapters, KVMs and EDIDless
                        panels may send no or incorrect EDID data sets.
                        specified address. The serial port must already be
                        setup and configured. Options are not yet supported.
 
+               efifb,[options]
+                       Start an early, unaccelerated console on the EFI
+                       memory mapped framebuffer (if available). On cache
+                       coherent non-x86 systems that use system memory for
+                       the framebuffer, pass the 'ram' option so that it is
+                       mapped with the correct attributes.
+
        earlyprintk=    [X86,SH,ARM,M68k,S390]
                        earlyprintk=vga
-                       earlyprintk=efi
                        earlyprintk=sclp
                        earlyprintk=xen
                        earlyprintk=serial[,ttySn[,baudrate]]
                        arch/x86/kernel/cpu/cpufreq/elanfreq.c.
 
        elevator=       [IOSCHED]
-                       Format: {"cfq" | "deadline" | "noop"}
-                       See Documentation/block/cfq-iosched.txt and
-                       Documentation/block/deadline-iosched.txt for details.
+                       Format: { "mq-deadline" | "kyber" | "bfq" }
+                       See Documentation/block/deadline-iosched.txt,
+                       Documentation/block/kyber-iosched.txt and
+                       Documentation/block/bfq-iosched.txt for details.
 
        elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
                        Specifies physical address of start of kernel core
                        to let secondary kernels in charge of setting up
                        LPIs.
 
+       irqchip.gicv3_pseudo_nmi= [ARM64]
+                       Enables support for pseudo-NMIs in the kernel. This
+                       requires the kernel to be built with
+                       CONFIG_ARM64_PSEUDO_NMI.
+
        irqfixup        [HW]
                        When an interrupt is not handled search all handlers
                        for it. Intended to get systems with badly broken
                        Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
                        the default is off.
 
+       kpti=           [ARM64] Control page table isolation of user
+                       and kernel address spaces.
+                       Default: enabled on cores which need mitigation.
+                       0: force disabled
+                       1: force enabled
+
        kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
                        Default is 0 (don't ignore, but inject #GP)
 
 
        lsm.debug       [SECURITY] Enable LSM initialization debugging output.
 
+       lsm=lsm1,...,lsmN
+                       [SECURITY] Choose order of LSM initialization. This
+                       overrides CONFIG_LSM, and the "security=" parameter.
+
        machvec=        [IA-64] Force the use of a particular machine-vector
                        (machvec) in a generic kernel.
                        Example: machvec=hpzx1_swiotlb
                        latencies, which will choose a value aligned
                        with the appropriate hardware boundaries.
 
-       rcutree.jiffies_till_sched_qs= [KNL]
-                       Set required age in jiffies for a
-                       given grace period before RCU starts
-                       soliciting quiescent-state help from
-                       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
                        first attempt to force quiescent states.
                        quiescent states.  Units are jiffies, minimum
                        value is one, and maximum value is HZ.
 
+       rcutree.jiffies_till_sched_qs= [KNL]
+                       Set required age in jiffies for a
+                       given grace period before RCU starts
+                       soliciting quiescent-state help from
+                       rcu_note_context_switch() and cond_resched().
+                       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.kthread_prio=    [KNL,BOOT]
                        Set the SCHED_FIFO priority of the RCU per-CPU
                        kthreads (rcuc/N). This value is also used for
                        This wake_up() will be accompanied by a
                        WARN_ONCE() splat and an ftrace_dump().
 
+       rcutree.sysrq_rcu= [KNL]
+                       Commandeer a sysrq key to dump out Tree RCU's
+                       rcu_node tree with an eye towards determining
+                       why a new grace period has not yet started.
+
        rcuperf.gp_async= [KNL]
                        Measure performance of asynchronous
                        grace-period primitives such as call_rcu().
                        Note: increases power consumption, thus should only be
                        enabled if running jitter sensitive (HPC/RT) workloads.
 
-       security=       [SECURITY] Choose a security module to enable at boot.
-                       If this boot parameter is not specified, only the first
-                       security module asking for security registration will be
-                       loaded. An invalid security module name will be treated
-                       as if no module has been chosen.
+       security=       [SECURITY] Choose a legacy "major" security module to
+                       enable at boot. This has been deprecated by the
+                       "lsm=" parameter.
 
        selinux=        [SELINUX] Disable or enable SELinux at boot time.
                        Format: { "0" | "1" }
        usbcore.authorized_default=
                        [USB] Default USB device authorization:
                        (default -1 = authorized except for wireless USB,
-                       0 = not authorized, 1 = authorized)
+                       0 = not authorized, 1 = authorized, 2 = authorized
+                       if device connected to internal port)
 
        usbcore.autosuspend=
                        [USB] The autosuspend time delay (in seconds) used
                        or other driver-specific files in the
                        Documentation/watchdog/ directory.
 
+       watchdog_thresh=
+                       [KNL]
+                       Set the hard lockup detector stall duration
+                       threshold in seconds. The soft lockup detector
+                       threshold is set to twice the value. A value of 0
+                       disables both lockup detectors. Default is 10
+                       seconds.
+
        workqueue.watchdog_thresh=
                        If CONFIG_WQ_WATCHDOG is configured, workqueue can
                        warn stall conditions and dump internal state to