Merge tag 'docs-4.12-2' of git://git.lwn.net/linux
[sfrench/cifs-2.6.git] / Documentation / admin-guide / kernel-parameters.txt
index e4c9e0e46b9586796a037ee3dc624d6ce1017817..15f79c27748df1611b1643b77ca68e2a5e7cfaab 100644 (file)
                        A valid base address must be provided, and the serial
                        port must already be setup and configured.
 
-               armada3700_uart,<addr>
+               ar3700_uart,<addr>
                        Start an early, polled-mode console on the
                        Armada 3700 serial port at the specified
                        address. The serial port must already be setup
                        extended tables themselves, and also PASID support. With
                        this option set, extended tables will not be used even
                        on hardware which claims to support them.
+               tboot_noforce [Default Off]
+                       Do not force the Intel IOMMU enabled under tboot.
+                       By default, tboot will force Intel IOMMU on, which
+                       could harm performance of some high-throughput
+                       devices like 40GBit network cards, even if identity
+                       mapping is enabled.
+                       Note that using this option lowers the security
+                       provided by tboot because it makes the system
+                       vulnerable to DMA attacks.
 
        intel_idle.max_cstate=  [KNL,HW,ACPI,X86]
                        0       disables intel_idle and fall back on acpi_idle.
                nobypass        [PPC/POWERNV]
                        Disable IOMMU bypass, using IOMMU for PCI devices.
 
+       iommu.passthrough=
+                       [ARM64] Configure DMA to bypass the IOMMU by default.
+                       Format: { "0" | "1" }
+                       0 - Use IOMMU translation for DMA.
+                       1 - Bypass the IOMMU for DMA.
+                       unset - Use IOMMU translation for DMA.
 
        io7=            [HW] IO7 for Marvel based alpha systems
                        See comment before marvel_specify_io7 in
                        and gids from such clients.  This is intended to ease
                        migration from NFSv2/v3.
 
-       objlayoutdriver.osd_login_prog=
-                       [NFS] [OBJLAYOUT] sets the pathname to the program which
-                       is used to automatically discover and login into new
-                       osd-targets. Please see:
-                       Documentation/filesystems/pnfs.txt for more explanations
-
        nmi_debug=      [KNL,SH] Specify one or more actions to take
                        when a NMI is triggered.
                        Format: [state][,regs][,debounce][,die]
        spia_pedr=
        spia_peddr=
 
+       srcutree.exp_holdoff [KNL]
+                       Specifies how many nanoseconds must elapse
+                       since the end of the last SRCU grace period for
+                       a given srcu_struct until the next normal SRCU
+                       grace period will be considered for automatic
+                       expediting.  Set to zero to disable automatic
+                       expediting.
+
        stacktrace      [FTRACE]
                        Enabled the stack tracer on boot up.