Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[muen/linux.git] / Documentation / admin-guide / kernel-parameters.txt
index 520fdec..e49311d 100644 (file)
        amijoy.map=     [HW,JOY] Amiga joystick support
                        Map of devices attached to JOY0DAT and JOY1DAT
                        Format: <a>,<b>
-                       See also Documentation/input/joystick.txt
+                       See also Documentation/input/joydev/joystick.rst
 
        analog.map=     [HW,JOY] Analog joystick and gamepad support
                        Specifies type or capabilities of an analog joystick
        bttv.card=      [HW,V4L] bttv (bt848 + bt878 based grabber cards)
        bttv.radio=     Most important insmod options are available as
                        kernel args too.
-       bttv.pll=       See Documentation/video4linux/bttv/Insmod-options
+       bttv.pll=       See Documentation/media/v4l-drivers/bttv.rst
        bttv.tuner=
 
        bulk_remove=off [PPC]  This parameter disables the use of the pSeries
                For now, only VisioBraille is supported.
 
        consoleblank=   [KNL] The console blank (screen saver) timeout in
-                       seconds. Defaults to 10*60 = 10mins. A value of 0
-                       disables the blank timer.
+                       seconds. A value of 0 disables the blank timer.
+                       Defaults to 0.
 
        coredump_filter=
                        [KNL] Change the default value for
                        It will be ignored when crashkernel=X,high is not used
                        or memory reserved is below 4G.
 
+       crossrelease_fullstack
+                       [KNL] Allow to record full stack trace in cross-release
+
        cryptomgr.notests
                         [KNL] Disable crypto self-tests
 
        db9.dev[2|3]=   [HW,JOY] Multisystem joystick support via parallel port
                        (one device per port)
                        Format: <port#>,<type>
-                       See also Documentation/input/joystick-parport.txt
+                       See also Documentation/input/devices/joystick-parport.rst
 
        ddebug_query=   [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
                        time. See
                        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
                        [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
                        support via parallel port (up to 5 devices per port)
                        Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
-                       See also Documentation/input/joystick-parport.txt
+                       See also Documentation/input/devices/joystick-parport.rst
 
        gamma=          [HW,DRM]
 
        irqaffinity=    [SMP] Set the default irq affinity mask
                        The argument is a cpu list, as described above.
 
+       irqchip.gicv2_force_probe=
+                       [ARM, ARM64]
+                       Format: <bool>
+                       Force the kernel to look for the second 4kB page
+                       of a GICv2 controller even if the memory range
+                       exposed by the device tree is too small.
+
        irqfixup        [HW]
                        When an interrupt is not handled search all handlers
                        for it. Intended to get systems with badly broken
        isapnp=         [ISAPNP]
                        Format: <RDP>,<reset>,<pci_scan>,<verbosity>
 
-       isolcpus=       [KNL,SMP] Isolate CPUs from the general scheduler.
-                       The argument is a cpu list, as described above.
+       isolcpus=       [KNL,SMP] Isolate a given set of CPUs from disturbance.
+                       [Deprecated - use cpusets instead]
+                       Format: [flag-list,]<cpu-list>
+
+                       Specify one or more CPUs to isolate from disturbances
+                       specified in the flag list (default: domain):
+
+                       nohz
+                         Disable the tick when a single task runs.
+                       domain
+                         Isolate from the general SMP balancing and scheduling
+                         algorithms. Note that performing domain isolation this way
+                         is irreversible: it's not possible to bring back a CPU to
+                         the domains once isolated through isolcpus. It's strongly
+                         advised to use cpusets instead to disable scheduler load
+                         balancing through the "cpuset.sched_load_balance" file.
+                         It offers a much more flexible interface where CPUs can
+                         move in and out of an isolated set anytime.
+
+                         You can move a process onto or off an "isolated" CPU via
+                         the CPU affinity syscalls or cpuset.
+                         <cpu number> begins at 0 and the maximum value is
+                         "number of CPUs in system - 1".
+
+                       The format of <cpu-list> is described above.
 
-                       This option can be used to specify one or more CPUs
-                       to isolate from the general SMP balancing and scheduling
-                       algorithms. You can move a process onto or off an
-                       "isolated" CPU via the CPU affinity syscalls or cpuset.
-                       <cpu number> begins at 0 and the maximum value is
-                       "number of CPUs in system - 1".
 
-                       This option is the preferred way to isolate CPUs. The
-                       alternative -- manually setting the CPU mask of all
-                       tasks in the system -- can cause problems and
-                       suboptimal load balancer performance.
 
        iucv=           [HW,NET]
 
                                ivrs_acpihid[00:14.5]=AMD0020:0
 
        js=             [HW,JOY] Analog joystick
-                       See Documentation/input/joystick.txt.
+                       See Documentation/input/joydev/joystick.rst.
 
        nokaslr         [KNL]
                        When CONFIG_RANDOMIZE_BASE is set, this disables
                        Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
                        the default is off.
 
-       kmemcheck=      [X86] Boot-time kmemcheck enable/disable/one-shot mode
-                       Valid arguments: 0, 1, 2
-                       kmemcheck=0 (disabled)
-                       kmemcheck=1 (enabled)
-                       kmemcheck=2 (one-shot mode)
-                       Default: 2 (one-shot mode)
-
        kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
                        Default is 0 (don't ignore, but inject #GP)
 
                        [KVM,ARM] Trap guest accesses to GICv3 common
                        system registers
 
+       kvm-arm.vgic_v4_enable=
+                       [KVM,ARM] Allow use of GICv4 for direct injection of
+                       LPIs.
+
        kvm-intel.ept=  [KVM,Intel] Disable extended page tables
                        (virtualized MMU) support on capable Intel chips.
                        Default is 1 (enabled)
                        s2idle  - Suspend-To-Idle
                        shallow - Power-On Suspend or equivalent (if supported)
                        deep    - Suspend-To-RAM or equivalent (if supported)
-                       See Documentation/power/states.txt.
+                       See Documentation/admin-guide/pm/sleep-states.rst.
 
        meye.*=         [HW] Set MotionEye Camera parameters
-                       See Documentation/video4linux/meye.txt.
+                       See Documentation/media/v4l-drivers/meye.rst.
 
        mfgpt_irq=      [IA-32] Specify the IRQ to use for the
                        Multi-Function General Purpose Timers on AMD Geode
 
        noalign         [KNL,ARM]
 
+       noaltinstr      [S390] Disables alternative instructions patching
+                       (CPU alternatives feature).
+
        noapic          [SMP,APIC] Tells the kernel to not make use of any
                        IOAPICs that may be present in the system.
 
 
        plip=           [PPT,NET] Parallel port network link
                        Format: { parport<nr> | timid | 0 }
-                       See also Documentation/parport.txt.
+                       See also Documentation/admin-guide/parport.rst.
 
        pmtmr=          [X86] Manual setup of pmtmr I/O Port.
                        Override pmtimer IOPort with a hex value.
                        allowed (eg kernel_enable_fpu()/kernel_disable_fpu()).
                        There is some performance impact when enabling this.
 
+       ppc_tm=         [PPC]
+                       Format: {"off"}
+                       Disable Hardware Transactional Memory
+
        print-fatal-signals=
                        [KNL] debug: print fatal signals
 
                        instead using the legacy FADT method
 
        profile=        [KNL] Enable kernel profiling via /proc/profile
-                       Format: [schedule,]<number>
+                       Format: [<profiletype>,]<number>
+                       Param: <profiletype>: "schedule", "sleep", or "kvm"
+                               [defaults to kernel profiling]
                        Param: "schedule" - profile schedule points.
-                       Param: <number> - step/bucket size as a power of 2 for
-                               statistical time based profiling.
                        Param: "sleep" - profile D-state sleeping (millisecs).
                                Requires CONFIG_SCHEDSTATS
                        Param: "kvm" - profile VM exits.
+                       Param: <number> - step/bucket size as a power of 2 for
+                               statistical time based profiling.
 
        prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
                        before loading.
        rcutorture.stall_cpu_holdoff= [KNL]
                        Time to wait (s) after boot before inducing stall.
 
+       rcutorture.stall_cpu_irqsoff= [KNL]
+                       Disable interrupts while stalling if set.
+
        rcutorture.stat_interval= [KNL]
                        Time (s) between statistics printk()s.
 
                        [KNL] Should the soft-lockup detector generate panics.
                        Format: <integer>
 
+                       A nonzero value instructs the soft-lockup detector
+                       to panic the machine when a soft-lockup occurs. This
+                       is also controlled by CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC
+                       which is the respective build-time switch to that
+                       functionality.
+
        softlockup_all_cpu_backtrace=
                        [KNL] Should the soft-lockup detector generate
                        backtraces on all cpus.
                        Used to run time disable IRQ_TIME_ACCOUNTING on any
                        platforms where RDTSC is slow and this accounting
                        can add overhead.
+                       [x86] unstable: mark the TSC clocksource as unstable, this
+                       marks the TSC unconditionally unstable at bootup and
+                       avoids any further wobbles once the TSC watchdog notices.
 
        turbografx.map[2|3]=    [HW,JOY]
                        TurboGraFX parallel port interface
                        Format:
                        <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
-                       See also Documentation/input/joystick-parport.txt
+                       See also Documentation/input/devices/joystick-parport.rst
 
        udbg-immortal   [PPC] When debugging early kernel crashes that
                        happen after console_init() and before a proper