Merge tag 'iommu-updates-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-block.git] / Documentation / admin-guide / kernel-parameters.txt

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 7c992b6d27fa5d429c6c1895302299227e9de5d6..5b5f1ba76bba1ff9fc92d19c46c3e3a75f7c9d57 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -856,6 +856,11 @@
                        causing system reset or hang due to sending
                        INIT from AP to BSP.
 
+       disable_counter_freezing [HW]
+                       Disable Intel PMU counter freezing feature.
+                       The feature only exists starting from
+                       Arch Perfmon v4 (Skylake and newer).
+
        disable_ddw     [PPC/PSERIES]
                        Disable Dynamic DMA Window support. Use this if
                        to workaround buggy firmware.
@@ -1385,6 +1390,11 @@
        hvc_iucv_allow= [S390]  Comma-separated list of z/VM user IDs.
                                If specified, z/VM IUCV HVC accepts connections
                                from listed z/VM user IDs only.
+
+       hv_nopvspin     [X86,HYPER_V] Disables the paravirt spinlock optimizations
+                                     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
@@ -1766,7 +1776,7 @@
                        Format: { "0" | "1" }
                        0 - Use IOMMU translation for DMA.
                        1 - Bypass the IOMMU for DMA.
-                       unset - Use IOMMU translation for DMA.
+                       unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
 
        io7=            [HW] IO7 for Marvel based alpha systems
                        See comment before marvel_specify_io7 in
@@ -2286,6 +2296,8 @@
        ltpc=           [NET]
                        Format: <io>,<irq>,<dma>
 
+       lsm.debug       [SECURITY] Enable LSM initialization debugging output.
+
        machvec=        [IA-64] Force the use of a particular machine-vector
                        (machvec) in a generic kernel.
                        Example: machvec=hpzx1_swiotlb
@@ -3552,14 +3564,14 @@
 
                        In kernels built with CONFIG_RCU_NOCB_CPU=y, set
                        the specified list of CPUs to be no-callback CPUs.
-                       Invocation of these CPUs' RCU callbacks will
-                       be offloaded to "rcuox/N" kthreads created for
-                       that purpose, where "x" is "b" for RCU-bh, "p"
-                       for RCU-preempt, and "s" for RCU-sched, and "N"
-                       is the CPU number.  This reduces OS jitter on the
-                       offloaded CPUs, which can be useful for HPC and
-                       real-time workloads.  It can also improve energy
-                       efficiency for asymmetric multiprocessors.
+                       Invocation of these CPUs' RCU callbacks will be
+                       offloaded to "rcuox/N" kthreads created for that
+                       purpose, where "x" is "p" for RCU-preempt, and
+                       "s" for RCU-sched, and "N" is the CPU number.
+                       This reduces OS jitter on the offloaded CPUs,
+                       which can be useful for HPC and real-time
+                       workloads.  It can also improve energy efficiency
+                       for asymmetric multiprocessors.
 
        rcu_nocb_poll   [KNL]
                        Rather than requiring that offloaded CPUs
@@ -3613,7 +3625,14 @@
                        Set required age in jiffies for a
                        given grace period before RCU starts
                        soliciting quiescent-state help from
-                       rcu_note_context_switch().
+                       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
@@ -3881,12 +3900,6 @@
        rcupdate.rcu_self_test= [KNL]
                        Run the RCU early boot self tests
 
-       rcupdate.rcu_self_test_bh= [KNL]
-                       Run the RCU bh early boot self tests
-
-       rcupdate.rcu_self_test_sched= [KNL]
-                       Run the RCU sched early boot self tests
-
        rdinit=         [KNL]
                        Format: <full_path>
                        Run specified binary instead of /init from the ramdisk,
@@ -4622,7 +4635,8 @@
 
        usbcore.old_scheme_first=
                        [USB] Start with the old device initialization
-                       scheme (default 0 = off).
+                       scheme,  applies only to low and full-speed devices
+                        (default 0 = off).
 
        usbcore.usbfs_memory_mb=
                        [USB] Memory limit (in MB) for buffers allocated by