Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
[sfrench/cifs-2.6.git] / Documentation / admin-guide / kernel-parameters.txt
index fd03e2b629bbcfda55847e0cddd973bdd7b3a708..d1d1da9110851933d5e6058f3ba9effc9191f678 100644 (file)
                        Format: { "off" | "enforce" | "fix" | "log" }
                        default: "enforce"
 
-       ima_appraise_tcb [IMA]
+       ima_appraise_tcb [IMA] Deprecated.  Use ima_policy= instead.
                        The builtin appraise policy appraises all files
                        owned by uid=0.
 
                        uid=0.
 
                        The "appraise_tcb" policy appraises the integrity of
-                       all files owned by root. (This is the equivalent
-                       of ima_appraise_tcb.)
+                       all files owned by root.
 
                        The "secure_boot" policy appraises the integrity
                        of files (eg. kexec kernel image, kernel modules,
        ip=             [IP_PNP]
                        See Documentation/filesystems/nfs/nfsroot.txt.
 
+       ipcmni_extend   [KNL] Extend the maximum number of unique System V
+                       IPC identifiers from 32,768 to 16,777,216.
+
        irqaffinity=    [SMP] Set the default irq affinity mask
                        The argument is a cpu list, as described above.
 
 
                        Default is 'flush'.
 
-                       For details see: Documentation/admin-guide/l1tf.rst
+                       For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
 
        l2cr=           [PPC]
 
                        Format: <first>,<last>
                        Specifies range of consoles to be captured by the MDA.
 
+       mds=            [X86,INTEL]
+                       Control mitigation for the Micro-architectural Data
+                       Sampling (MDS) 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 MDS mitigation. The
+                       options are:
+
+                       full       - Enable MDS mitigation on vulnerable CPUs
+                       full,nosmt - Enable MDS mitigation and disable
+                                    SMT on vulnerable CPUs
+                       off        - Unconditionally disable MDS mitigation
+
+                       Not specifying this option is equivalent to
+                       mds=full.
+
+                       For details see: Documentation/admin-guide/hw-vuln/mds.rst
+
        mem=nn[KMG]     [KNL,BOOT] Force usage of a specific amount of memory
                        Amount of memory to be used when the kernel is not able
                        to see the whole system memory or for test.
                                               spec_store_bypass_disable=off [X86,PPC]
                                               ssbd=force-off [ARM64]
                                               l1tf=off [X86]
+                                              mds=off [X86]
 
                        auto (default)
                                Mitigate all CPU vulnerabilities, but leave SMT
                                if needed.  This is for users who always want to
                                be fully mitigated, even if it means losing SMT.
                                Equivalent to: l1tf=flush,nosmt [X86]
+                                              mds=full,nosmt [X86]
 
        mminit_loglevel=
                        [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
                        noexec=on: enable non-executable mappings (default)
                        noexec=off: disable non-executable mappings
 
-       nosmap          [X86]
+       nosmap          [X86,PPC]
                        Disable SMAP (Supervisor Mode Access Prevention)
                        even if it is supported by processor.
 
-       nosmep          [X86]
+       nosmep          [X86,PPC]
                        Disable SMEP (Supervisor Mode Execution Prevention)
                        even if it is supported by processor.
 
                        This will also cause panics on machine check exceptions.
                        Useful together with panic=30 to trigger a reboot.
 
+       page_alloc.shuffle=
+                       [KNL] Boolean flag to control whether the page allocator
+                       should randomize its free lists. The randomization may
+                       be automatically enabled if the kernel detects it is
+                       running on a platform with a direct-mapped memory-side
+                       cache, and this parameter can be used to
+                       override/disable that behavior. The state of the flag
+                       can be read from sysfs at:
+                       /sys/module/page_alloc/parameters/shuffle.
+
        page_owner=     [KNL] Boot-time page_owner enabling option.
                        Storage of the information about who allocated
                        each page is disabled in default. With this switch,
                                [[,]s[mp]#### \
                                [[,]b[ios] | a[cpi] | k[bd] | t[riple] | e[fi] | p[ci]] \
                                [[,]f[orce]
-                       Where reboot_mode is one of warm (soft) or cold (hard) or gpio,
+                       Where reboot_mode is one of warm (soft) or cold (hard) or gpio
+                                       (prefix with 'panic_' to set mode for panic
+                                       reboot only),
                              reboot_type is one of bios, acpi, kbd, triple, efi, or pci,
                              reboot_force is either force or not specified,
                              reboot_cpu is s[mp]#### with #### being the processor