Merge tag 'dmaengine-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul...
[linux-2.6-microblaze.git] / Documentation / admin-guide / kernel-parameters.txt
index ec5411c..91ba391 100644 (file)
                        do not want to use tracing_snapshot_alloc() as it needs
                        to be done where GFP_KERNEL allocations are allowed.
 
+       allow_mismatched_32bit_el0 [ARM64]
+                       Allow execve() of 32-bit applications and setting of the
+                       PER_LINUX32 personality on systems where only a strict
+                       subset of the CPUs support 32-bit EL0. When this
+                       parameter is present, the set of CPUs supporting 32-bit
+                       EL0 is indicated by /sys/devices/system/cpu/aarch32_el0
+                       and hot-unplug operations may be restricted.
+
+                       See Documentation/arm64/asymmetric-32bit.rst for more
+                       information.
+
        amd_iommu=      [HW,X86-64]
                        Pass parameters to the AMD IOMMU driver in the system.
                        Possible values are:
-                       fullflush - enable flushing of IO/TLB entries when
-                                   they are unmapped. Otherwise they are
-                                   flushed before they will be reused, which
-                                   is a lot of faster
+                       fullflush - Deprecated, equivalent to iommu.strict=1
                        off       - do not initialize any AMD IOMMU found in
                                    the system
                        force_isolation - Force device isolation for all
        arm64.nopauth   [ARM64] Unconditionally disable Pointer Authentication
                        support
 
+       arm64.nomte     [ARM64] Unconditionally disable Memory Tagging Extension
+                       support
+
        ataflop=        [HW,M68k]
 
        atarimouse=     [HW,MOUSE] Atari Mouse
                        this case, gfx device will use physical address for
                        DMA.
                strict [Default Off]
-                       With this option on every unmap_single operation will
-                       result in a hardware IOTLB flush operation as opposed
-                       to batching them for performance.
+                       Deprecated, equivalent to iommu.strict=1.
                sp_off [Default Off]
                        By default, super page will be supported if Intel IOMMU
                        has the capability. With this option, super page will
                        not be supported.
-               sm_on [Default Off]
-                       By default, scalable mode will be disabled even if the
-                       hardware advertises that it has support for the scalable
-                       mode translation. With this option set, scalable mode
-                       will be used on hardware which claims to support it.
+               sm_on
+                       Enable the Intel IOMMU scalable mode if the hardware
+                       advertises that it has support for the scalable mode
+                       translation.
+               sm_off
+                       Disallow use of the Intel IOMMU scalable mode.
                tboot_noforce [Default Off]
                        Do not force the Intel IOMMU enabled under tboot.
                        By default, tboot will force Intel IOMMU on, which
                          throughput at the cost of reduced device isolation.
                          Will fall back to strict mode if not supported by
                          the relevant IOMMU driver.
-                       1 - Strict mode (default).
+                       1 - Strict mode.
                          DMA unmap operations invalidate IOMMU hardware TLBs
                          synchronously.
-                       Note: on x86, the default behaviour depends on the
-                       equivalent driver-specific parameters, but a strict
-                       mode explicitly specified by either method takes
-                       precedence.
+                       unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
+                       Note: on x86, strict mode specified via one of the
+                       legacy driver-specific options takes precedence.
 
        iommu.passthrough=
                        [ARM64, X86] Configure DMA to bypass the IOMMU by default.
                        feature (tagged TLBs) on capable Intel chips.
                        Default is 1 (enabled)
 
+       l1d_flush=      [X86,INTEL]
+                       Control mitigation for L1D based snooping vulnerability.
+
+                       Certain CPUs are vulnerable to an exploit against CPU
+                       internal buffers which can forward information to a
+                       disclosure gadget under certain conditions.
+
+                       In vulnerable processors, the speculatively
+                       forwarded data can be used in a cache side channel
+                       attack, to access data to which the attacker does
+                       not have direct access.
+
+                       This parameter controls the mitigation. The
+                       options are:
+
+                       on         - enable the interface for the mitigation
+
        l1tf=           [X86] Control mitigation of the L1TF vulnerability on
                              affected CPUs
 
                        Format: <bool>  (1/Y/y=enable, 0/N/n=disable)
                        default: disabled
 
+       printk.console_no_auto_verbose=
+                       Disable console loglevel raise on oops, panic
+                       or lockdep-detected issues (only if lock debug is on).
+                       With an exception to setups with low baudrate on
+                       serial console, keeping this 0 is a good choice
+                       in order to provide more debug information.
+                       Format: <bool>
+                       default: 0 (auto_verbose is enabled)
+
        printk.devkmsg={on,off,ratelimit}
                        Control writing to /dev/kmsg.
                        on - unlimited logging to /dev/kmsg from userspace
 
        reboot=         [KNL]
                        Format (x86 or x86_64):
-                               [w[arm] | c[old] | h[ard] | s[oft] | g[pio]] \
+                               [w[arm] | c[old] | h[ard] | s[oft] | g[pio]] | d[efault] \
                                [[,]s[mp]#### \
                                [[,]b[ios] | a[cpi] | k[bd] | t[riple] | e[fi] | p[ci]] \
                                [[,]f[orce]
        sa1100ir        [NET]
                        See drivers/net/irda/sa1100_ir.c.
 
-       sbni=           [NET] Granch SBNI12 leased line adapter
-
        sched_verbose   [KNL] Enables verbose scheduler debug messages.
 
        schedstats=     [KNL,X86] Enable or disable scheduled statistics.