BLACKFIN Blackfin architecture is enabled.
CLK Common clock infrastructure is enabled.
CMA Contiguous Memory Area support is enabled.
+ DM Device mapper support is enabled.
DRM Direct Rendering Management support is enabled.
DYNAMIC_DEBUG Build in debug messages and enable them at runtime
EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
dis_ucode_ldr [X86] Disable the microcode loader.
+ dm= [DM] Allows early creation of a device-mapper device.
+ See Documentation/device-mapper/boot.txt.
+
+ dmasound= [HW,OSS] Sound subsystem buff
+
dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
this option disables the debugging code at boot.
In such case C2/C3 won't be used again.
idle=nomwait: Disable mwait for CPU C-states
+ ieee754= [MIPS] Select IEEE Std 754 conformance mode
+ Format: { strict | legacy | 2008 | relaxed }
+ Default: strict
+
+ Choose which programs will be accepted for execution
+ based on the IEEE 754 NaN encoding(s) supported by
+ the FPU and the NaN encoding requested with the value
+ of an ELF file header flag individually set by each
+ binary. Hardware implementations are permitted to
+ support either or both of the legacy and the 2008 NaN
+ encoding mode.
+
+ Available settings are as follows:
+ strict accept binaries that request a NaN encoding
+ supported by the FPU
+ legacy only accept legacy-NaN binaries, if supported
+ by the FPU
+ 2008 only accept 2008-NaN binaries, if supported
+ by the FPU
+ relaxed accept any binaries regardless of whether
+ supported by the FPU
+
+ The FPU emulator is always able to support both NaN
+ encodings, so if no FPU hardware is present or it has
+ been disabled with 'nofpu', then the settings of
+ 'legacy' and '2008' strap the emulator accordingly,
+ 'relaxed' straps the emulator for both legacy-NaN and
+ 2008-NaN, whereas 'strict' enables legacy-NaN only on
+ legacy processors and both NaN encodings on MIPS32 or
+ MIPS64 CPUs.
+
+ The setting for ABS.fmt/NEG.fmt instruction execution
+ mode generally follows that for the NaN encoding,
+ except where unsupported by hardware.
+
ignore_loglevel [KNL]
Ignore loglevel setting - this will print /all/
kernel messages to the console. Useful for debugging.
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
+ off - Unconditionally disable MDS mitigation
+
+ On TAA-affected machines, mds=off can be prevented by
+ an active TAA mitigation as both vulnerabilities are
+ mitigated with the same mechanism so in order to disable
+ this mitigation, you need to specify tsx_async_abort=off
+ too.
+
+ Not specifying this option is equivalent to
+ mds=full.
+
+ For details see: Documentation/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.
in the "bleeding edge" mini2440 support kernel at
http://repo.or.cz/w/linux-2.6/mini2440.git
+ mitigations=
+ [X86] Control optional mitigations for CPU
+ vulnerabilities. This is a set of curated,
+ arch-independent options, each of which is an
+ aggregation of existing arch-specific options.
+
+ off
+ Disable all optional CPU mitigations. This
+ improves system performance, but it may also
+ expose users to several CPU vulnerabilities.
+ Equivalent to: nopti [X86]
+ nospectre_v1 [X86]
+ nospectre_v2 [X86]
+ spectre_v2_user=off [X86]
+ spec_store_bypass_disable=off [X86]
+ mds=off [X86]
+ tsx_async_abort=off [X86]
+
+ auto (default)
+ Mitigate all CPU vulnerabilities, but leave SMT
+ enabled, even if it's vulnerable. This is for
+ users who don't want to be surprised by SMT
+ getting disabled across kernel upgrades, or who
+ have other ways of avoiding SMT-based attacks.
+ Equivalent to: (default behavior)
+
mminit_loglevel=
[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
parameter allows control of the logging verbosity for
noexec=on: enable non-executable mappings (default)
noexec=off: disable non-executable mappings
+ noexec [MIPS]
+ Force indicating stack and heap as non-executable or
+ executable regardless of PT_GNU_STACK entry or CPU XI
+ (execute inhibit) support. Valid valuess are: on, off.
+ noexec=on: force indicating non-executable
+ stack and heap
+ noexec=off: force indicating executable
+ stack and heap
+ If this parameter is omitted, stack and heap will be
+ indicated non-executable or executable as they are
+ actually set up, which depends on PT_GNU_STACK entry
+ and possibly other factors (for instance, CPU XI
+ support).
+ NOTE: Using noexec=on on a system without CPU XI
+ support is not recommended since there is no actual
+ HW support that provide non-executable stack/heap.
+ Use only for debugging purposes and not in a
+ production environment.
+
nosmap [X86]
Disable SMAP (Supervisor Mode Access Prevention)
even if it is supported by processor.
nohugeiomap [KNL,x86] Disable kernel huge I/O mappings.
- nospectre_v1 [PPC] Disable mitigations for Spectre Variant 1 (bounds
- check bypass). With this option data leaks are possible
- in the system.
+ nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1
+ (bounds check bypass). With this option data leaks are
+ possible in the system.
nospectre_v2 [X86,PPC_FSL_BOOK3E] Disable all mitigations for the Spectre variant 2
(indirect branch prediction) vulnerability. System may
Run specified binary instead of /init from the ramdisk,
used for early userspace startup. See initrd.
+ rdrand= [X86]
+ force - Override the decision by the kernel to hide the
+ advertisement of RDRAND support (this affects
+ certain AMD processors because of buggy BIOS
+ support, specifically around the suspend/resume
+ path).
+
reboot= [KNL]
Format (x86 or x86_64):
[w[arm] | c[old] | h[ard] | s[oft] | g[pio]] \
ro [KNL] Mount root device read-only on boot
+ rodata= [KNL]
+ on Mark read-only kernel memory as read-only (default).
+ off Leave read-only kernel memory writable for debugging.
+
root= [KNL] Root filesystem
See name_to_dev_t comment in init/do_mounts.c.
platforms where RDTSC is slow and this accounting
can add overhead.
+ tsx= [X86] Control Transactional Synchronization
+ Extensions (TSX) feature in Intel processors that
+ support TSX control.
+
+ This parameter controls the TSX feature. The options are:
+
+ on - Enable TSX on the system. Although there are
+ mitigations for all known security vulnerabilities,
+ TSX has been known to be an accelerator for
+ several previous speculation-related CVEs, and
+ so there may be unknown security risks associated
+ with leaving it enabled.
+
+ off - Disable TSX on the system. (Note that this
+ option takes effect only on newer CPUs which are
+ not vulnerable to MDS, i.e., have
+ MSR_IA32_ARCH_CAPABILITIES.MDS_NO=1 and which get
+ the new IA32_TSX_CTRL MSR through a microcode
+ update. This new MSR allows for the reliable
+ deactivation of the TSX functionality.)
+
+ auto - Disable TSX if X86_BUG_TAA is present,
+ otherwise enable TSX on the system.
+
+ Not specifying this option is equivalent to tsx=off.
+
+ See Documentation/hw-vuln/tsx_async_abort.rst
+ for more details.
+
+ tsx_async_abort= [X86,INTEL] Control mitigation for the TSX Async
+ Abort (TAA) vulnerability.
+
+ Similar to Micro-architectural Data Sampling (MDS)
+ certain CPUs that support Transactional
+ Synchronization Extensions (TSX) 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 TAA mitigation. The
+ options are:
+
+ full - Enable TAA mitigation on vulnerable CPUs
+ if TSX is enabled.
+
+ off - Unconditionally disable TAA mitigation
+
+ On MDS-affected machines, tsx_async_abort=off can be
+ prevented by an active MDS mitigation as both vulnerabilities
+ are mitigated with the same mechanism so in order to disable
+ this mitigation, you need to specify mds=off too.
+
+ Not specifying this option is equivalent to
+ tsx_async_abort=full. On CPUs which are MDS affected
+ and deploy MDS mitigation, TAA mitigation is not
+ required and doesn't provide any additional
+ mitigation.
+
+ For details see:
+ Documentation/hw-vuln/tsx_async_abort.rst
+
turbografx.map[2|3]= [HW,JOY]
TurboGraFX parallel port interface
Format: