Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index dbb6806..611172f 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -22,11 +22,13 @@
default: 0
acpi_backlight= [HW,ACPI]
- acpi_backlight=vendor
- acpi_backlight=video
- If set to vendor, prefer vendor specific driver
+ { vendor | video | native | none }
+ If set to vendor, prefer vendor-specific driver
(e.g. thinkpad_acpi, sony_acpi, etc.) instead
of the ACPI video.ko driver.
+ If set to video, use the ACPI video.ko driver.
+ If set to native, use the device's native backlight mode.
+ If set to none, disable the ACPI backlight interface.
acpi_force_32bit_fadt_addr
force FADT to use 32 bit addresses rather than the
@@ -354,7 +356,7 @@
shot down by NMI
autoconf= [IPV6]
- See Documentation/networking/ipv6.txt.
+ See Documentation/networking/ipv6.rst.
show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller
Limit apic dumping. The parameter defines the maximal
@@ -441,15 +443,22 @@
no delay (0).
Format: integer
- bootmem_debug [KNL] Enable bootmem allocator debug messages.
+ bootconfig [KNL]
+ Extended command line options can be added to an initrd
+ and this will cause the kernel to look for it.
+
+ See Documentation/admin-guide/bootconfig.rst
bert_disable [ACPI]
Disable BERT OS support on buggy BIOSes.
+ bgrt_disable [ACPI][X86]
+ Disable BGRT to avoid flickering OEM logo.
+
bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
bttv.radio= Most important insmod options are available as
kernel args too.
- bttv.pll= See Documentation/media/v4l-drivers/bttv.rst
+ bttv.pll= See Documentation/admin-guide/media/bttv.rst
bttv.tuner=
bulk_remove=off [PPC] This parameter disables the use of the pSeries
@@ -517,7 +526,8 @@
1 -- check protection requested by application.
Default value is set via a kernel config option.
Value can be changed at runtime via
- /selinux/checkreqprot.
+ /sys/fs/selinux/checkreqprot.
+ Setting checkreqprot to 1 is deprecated.
cio_ignore= [S390]
See Documentation/s390/common_io.rst for details.
@@ -587,13 +597,24 @@
some critical bits.
cma=nn[MG]@[start[MG][-end[MG]]]
- [ARM,X86,KNL]
+ [KNL,CMA]
Sets the size of kernel global memory area for
contiguous memory allocations and optionally the
placement constraint by the physical address range of
memory allocations. A value of 0 disables CMA
altogether. For more information, see
- include/linux/dma-contiguous.h
+ kernel/dma/contiguous.c
+
+ cma_pernuma=nn[MG]
+ [ARM64,KNL]
+ Sets the size of kernel per-numa memory area for
+ contiguous memory allocations. A value of 0 disables
+ per-numa CMA altogether. And If this option is not
+ specificed, the default value is 0.
+ With per-numa CMA enabled, DMA users on node nid will
+ first try to allocate buffer from the pernuma area
+ which is located in node nid, if the allocation fails,
+ they will fallback to the global default memory area.
cmo_free_hint= [PPC] Format: { yes | no }
Specify whether pages are marked as being inactive
@@ -634,7 +655,7 @@
See Documentation/admin-guide/serial-console.rst for more
information. See
- Documentation/networking/netconsole.txt for an
+ Documentation/networking/netconsole.rst for an
alternative.
uart[8250],io,<addr>[,options]
@@ -681,7 +702,7 @@
coredump_filter=
[KNL] Change the default value for
/proc/<pid>/coredump_filter.
- See also Documentation/filesystems/proc.txt.
+ See also Documentation/filesystems/proc.rst.
coresight_cpu_debug.enable
[ARM,ARM64]
@@ -699,6 +720,11 @@
cpufreq.off=1 [CPU_FREQ]
disable the cpufreq sub-system
+ cpufreq.default_governor=
+ [CPU_FREQ] Name of the default cpufreq governor or
+ policy to use. This governor must be registered in the
+ kernel before the cpufreq driver probes.
+
cpu_init_udelay=N
[X86] Delay for N microsec between assert and de-assert
of APIC INIT to start processors. This delay occurs
@@ -715,7 +741,7 @@
memory region [offset, offset + size] for that kernel
image. If '@offset' is omitted, then a suitable offset
is selected automatically.
- [KNL, x86_64] select a region under 4G first, and
+ [KNL, X86-64] Select a region under 4G first, and
fall back to reserve region above 4G when '@offset'
hasn't been specified.
See Documentation/admin-guide/kdump/kdump.rst for further details.
@@ -728,14 +754,14 @@
Documentation/admin-guide/kdump/kdump.rst for an example.
crashkernel=size[KMG],high
- [KNL, x86_64] range could be above 4G. Allow kernel
+ [KNL, X86-64] range could be above 4G. Allow kernel
to allocate physical memory region from top, so could
be above 4G if system have more than 4G ram installed.
Otherwise memory region will be allocated below 4G, if
available.
It will be ignored if crashkernel=X is specified.
crashkernel=size[KMG],low
- [KNL, x86_64] range under 4G. When crashkernel=X,high
+ [KNL, X86-64] range under 4G. When crashkernel=X,high
is passed, kernel could allocate physical memory region
above 4G, that cause second kernel crash on system
that require some amount of low memory, e.g. swiotlb
@@ -823,19 +849,37 @@
useful to also enable the page_owner functionality.
on: enable the feature
+ debugfs= [KNL] This parameter enables what is exposed to userspace
+ and debugfs internal clients.
+ Format: { on, no-mount, off }
+ on: All functions are enabled.
+ no-mount:
+ Filesystem is not registered but kernel clients can
+ access APIs and a crashkernel can be used to read
+ its content. There is nothing to mount.
+ off: Filesystem is not registered and clients
+ get a -EPERM as result when trying to register files
+ or directories within debugfs.
+ This is equivalent of the runtime functionality if
+ debugfs was not enabled in the kernel at all.
+ Default value is set in build-time with a kernel configuration.
+
debugpat [X86] Enable PAT debugging
decnet.addr= [HW,NET]
Format: <area>[,<node>]
- See also Documentation/networking/decnet.txt.
+ See also Documentation/networking/decnet.rst.
default_hugepagesz=
- [same as hugepagesz=] The size of the default
- HugeTLB page size. This is the size represented by
- the legacy /proc/ hugepages APIs, used for SHM, and
- default size when mounting hugetlbfs filesystems.
- Defaults to the default architecture's huge page size
- if not specified.
+ [HW] The size of the default HugeTLB page. This is
+ the size represented by the legacy /proc/ hugepages
+ APIs. In addition, this is the default hugetlb size
+ used for shmget(), mmap() and mounting hugetlbfs
+ filesystems. If not specified, defaults to the
+ architecture's default huge page size. Huge page
+ sizes are architecture dependent. See also
+ Documentation/admin-guide/mm/hugetlbpage.rst.
+ Format: size[KMG]
deferred_probe_timeout=
[KNL] Debugging option to set a timeout in seconds for
@@ -846,6 +890,18 @@
dump out devices still on the deferred probe list after
retrying.
+ dfltcc= [HW,S390]
+ Format: { on | off | def_only | inf_only | always }
+ on: s390 zlib hardware support for compression on
+ level 1 and decompression (default)
+ off: No s390 zlib hardware support
+ def_only: s390 zlib hardware support for deflate
+ only (compression on level 1)
+ inf_only: s390 zlib hardware support for inflate
+ only (decompression)
+ always: Same as 'on' but ignores the selected compression
+ level always using hardware support (used for debugging)
+
dhash_entries= [KNL]
Set number of hash buckets for dentry cache.
@@ -855,8 +911,13 @@
can be useful when debugging issues that require an SLB
miss to occur.
+ stress_slb [PPC]
+ Limits the number of kernel SLB entries, and flushes
+ them frequently to increase the rate of SLB faults
+ on kernel addresses.
+
disable= [IPV6]
- See Documentation/networking/ipv6.txt.
+ See Documentation/networking/ipv6.rst.
hardened_usercopy=
[KNL] Under CONFIG_HARDENED_USERCOPY, whether
@@ -872,6 +933,10 @@
disable_radix [PPC]
Disable RADIX MMU mode on POWER9
+ radix_hcall_invalidate=on [PPC/PSERIES]
+ Disable RADIX GTSE feature and use hcall for TLB
+ invalidate.
+
disable_tlbie [PPC]
Disable TLBIE instruction. Currently does not work
with KVM, with HASH MMU, or with coherent accelerators.
@@ -892,11 +957,11 @@
Arch Perfmon v4 (Skylake and newer).
disable_ddw [PPC/PSERIES]
- Disable Dynamic DMA Window support. Use this if
+ Disable Dynamic DMA Window support. Use this
to workaround buggy firmware.
disable_ipv6= [IPV6]
- See Documentation/networking/ipv6.txt.
+ See Documentation/networking/ipv6.rst.
disable_mtrr_cleanup [X86]
The kernel tries to adjust MTRR layout from continuous
@@ -946,7 +1011,7 @@
edid/1680x1050.bin, or edid/1920x1080.bin is given
and no file with the same name exists. Details and
instructions how to build your own EDID data are
- available in Documentation/driver-api/edid.rst. An EDID
+ available in Documentation/admin-guide/edid.rst. An EDID
data set will only be used for a particular connector,
if its name and a colon are prepended to the EDID
name. Each connector may use a unique EDID data
@@ -971,19 +1036,15 @@
what data is available or for reverse-engineering.
dyndbg[="val"] [KNL,DYNAMIC_DEBUG]
- module.dyndbg[="val"]
+ <module>.dyndbg[="val"]
Enable debug messages at boot time. See
Documentation/admin-guide/dynamic-debug-howto.rst
for details.
- nompx [X86] Disables Intel Memory Protection Extensions.
- See Documentation/x86/intel_mpx.rst for more
- information about the feature.
-
nopku [X86] Disable Memory Protection Keys CPU feature found
in some Intel CPUs.
- module.async_probe [KNL]
+ <module>.async_probe [KNL]
Enable asynchronous probe on this module.
early_ioremap_debug [KNL]
@@ -993,12 +1054,10 @@
earlycon= [KNL] Output early console device and options.
- [ARM64] The early console is determined by the
- stdout-path property in device tree's chosen node,
- or determined by the ACPI SPCR table.
-
- [X86] When used with no options the early console is
- determined by the ACPI SPCR table.
+ When used with no options, the early console is
+ determined by stdout-path property in device tree's
+ chosen node or the ACPI SPCR table if supported by
+ the platform.
cdns,<addr>[,options]
Start an early, polled-mode console on a Cadence
@@ -1091,6 +1150,12 @@
A valid base address must be provided, and the serial
port must already be setup and configured.
+ ec_imx21,<addr>
+ ec_imx6q,<addr>
+ Start an early, polled-mode, output-only console on the
+ Freescale i.MX UART at the specified address. The UART
+ must already be setup and configured.
+
ar3700_uart,<addr>
Start an early, polled-mode console on the
Armada 3700 serial port at the specified
@@ -1111,7 +1176,7 @@
mapped with the correct attributes.
linflex,<addr>
- Use early console provided by Freescale LinFlex UART
+ Use early console provided by Freescale LINFlexD UART
serial driver for NXP S32V234 SoCs. A valid base
address must be provided, and the serial port must
already be setup and configured.
@@ -1174,19 +1239,34 @@
This is designed to be used in conjunction with
the boot argument: earlyprintk=vga
+ This parameter works in place of the kgdboc parameter
+ but can only be used if the backing tty is available
+ very early in the boot process. For early debugging
+ via a serial port see kgdboc_earlycon instead.
+
edd= [EDD]
Format: {"off" | "on" | "skip[mbr]"}
efi= [EFI]
- Format: { "old_map", "nochunk", "noruntime", "debug" }
- old_map [X86-64]: switch to the old ioremap-based EFI
- runtime services mapping. 32-bit still uses this one by
- default.
+ Format: { "debug", "disable_early_pci_dma",
+ "nochunk", "noruntime", "nosoftreserve",
+ "novamap", "no_disable_early_pci_dma" }
+ debug: enable misc debug output.
+ disable_early_pci_dma: disable the busmaster bit on all
+ PCI bridges while in the EFI boot stub.
nochunk: disable reading files in "chunks" in the EFI
boot stub, as chunking can cause problems with some
firmware implementations.
noruntime : disable EFI runtime services support
- debug: enable misc debug output
+ nosoftreserve: The EFI_MEMORY_SP (Specific Purpose)
+ attribute may cause the kernel to reserve the
+ memory range for a memory mapping driver to
+ claim. Specify efi=nosoftreserve to disable this
+ reservation and treat the memory by its base type
+ (i.e. EFI_CONVENTIONAL_MEMORY / "System RAM").
+ novamap: do not call SetVirtualAddressMap().
+ no_disable_early_pci_dma: Leave the busmaster bit set
+ on all PCI bridges while in the EFI boot stub
efi_no_storage_paranoia [EFI; X86]
Using this parameter you can use more than 50% of
@@ -1199,15 +1279,21 @@
updating original EFI memory map.
Region of memory which aa attribute is added to is
from ss to ss+nn.
+
If efi_fake_mem=2G@4G:0x10000,2G@0x10a0000000:0x10000
is specified, EFI_MEMORY_MORE_RELIABLE(0x10000)
attribute is added to range 0x100000000-0x180000000 and
0x10a0000000-0x1120000000.
+ If efi_fake_mem=8G@9G:0x40000 is specified, the
+ EFI_MEMORY_SP(0x40000) attribute is added to
+ range 0x240000000-0x43fffffff.
+
Using this parameter you can do debugging of EFI memmap
- related feature. For example, you can do debugging of
+ related features. For example, you can do debugging of
Address Range Mirroring feature even if your box
- doesn't support it.
+ doesn't support it, or mark specific memory as
+ "soft reserved".
efivar_ssdt= [EFI; X86] Name of an EFI variable that contains an SSDT
that is to be dynamically loaded by Linux. If there are
@@ -1246,7 +1332,8 @@
0 -- permissive (log only, no denials).
1 -- enforcing (deny and log).
Default value is 0.
- Value can be changed at runtime via /selinux/enforce.
+ Value can be changed at runtime via
+ /sys/fs/selinux/enforce.
erst_disable [ACPI]
Disable Error Record Serialization Table (ERST)
@@ -1262,12 +1349,18 @@
current integrity status.
failslab=
+ fail_usercopy=
fail_page_alloc=
fail_make_request=[KNL]
General fault injection mechanism.
Format: <interval>,<probability>,<space>,<times>
See also Documentation/fault-injection/.
+ fb_tunnels= [NET]
+ Format: { initns | none }
+ See Documentation/admin-guide/sysctl/net.rst for
+ fb_tunnels_only_for_init_ns
+
floppy= [HW]
See Documentation/admin-guide/blockdev/floppy.rst.
@@ -1328,6 +1421,24 @@
can be changed at run time by the max_graph_depth file
in the tracefs tracing directory. default: 0 (no limit)
+ fw_devlink= [KNL] Create device links between consumer and supplier
+ devices by scanning the firmware to infer the
+ consumer/supplier relationships. This feature is
+ especially useful when drivers are loaded as modules as
+ it ensures proper ordering of tasks like device probing
+ (suppliers first, then consumers), supplier boot state
+ clean up (only after all consumers have probed),
+ suspend/resume & runtime PM (consumers first, then
+ suppliers).
+ Format: { off | permissive | on | rpm }
+ off -- Don't create device links from firmware info.
+ permissive -- Create device links from firmware info
+ but use it only for ordering boot state clean
+ up (sync_state() calls).
+ on -- Create device links from firmware info and use it
+ to enforce probe and suspend/resume ordering.
+ rpm -- Like "on", but also use to order runtime PM.
+
gamecon.map[2|3]=
[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
support via parallel port (up to 5 devices per port)
@@ -1336,7 +1447,7 @@
gamma= [HW,DRM]
- gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
+ gart_fix_e820= [X86-64] disable the fix e820 for K8 GART
Format: off | on
default: on
@@ -1380,7 +1491,7 @@
hardlockup_all_cpu_backtrace=
[KNL] Should the hard-lockup detector generate
backtraces on all cpus.
- Format: <integer>
+ Format: 0 | 1
hashdist= [KNL,NUMA] Large hashes allocated during boot
are distributed across NUMA nodes. Defaults on
@@ -1419,19 +1530,38 @@
hpet_mmap= [X86, HPET_MMAP] Allow userspace to mmap HPET
registers. Default set by CONFIG_HPET_MMAP_DEFAULT.
- hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
- hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
- On x86-64 and powerpc, this option can be specified
- multiple times interleaved with hugepages= to reserve
- huge pages of different sizes. Valid pages sizes on
- x86-64 are 2M (when the CPU supports "pse") and 1G
- (when the CPU supports the "pdpe1gb" cpuinfo flag).
+ hugetlb_cma= [HW] The size of a cma area used for allocation
+ of gigantic hugepages.
+ Format: nn[KMGTPE]
+
+ Reserve a cma area of given size and allocate gigantic
+ hugepages using the cma allocator. If enabled, the
+ boot-time allocation of gigantic hugepages is skipped.
+
+ hugepages= [HW] Number of HugeTLB pages to allocate at boot.
+ If this follows hugepagesz (below), it specifies
+ the number of pages of hugepagesz to be allocated.
+ If this is the first HugeTLB parameter on the command
+ line, it specifies the number of pages to allocate for
+ the default huge page size. See also
+ Documentation/admin-guide/mm/hugetlbpage.rst.
+ Format: <integer>
+
+ hugepagesz=
+ [HW] The size of the HugeTLB pages. This is used in
+ conjunction with hugepages (above) to allocate huge
+ pages of a specific size at boot. The pair
+ hugepagesz=X hugepages=Y can be specified once for
+ each supported huge page size. Huge page sizes are
+ architecture dependent. See also
+ Documentation/admin-guide/mm/hugetlbpage.rst.
+ Format: size[KMG]
hung_task_panic=
[KNL] Should the hung task detector generate panics.
- Format: <integer>
+ Format: 0 | 1
- A nonzero value instructs the kernel to panic when a
+ A value of 1 instructs the kernel to panic when a
hung task is detected. The default value is controlled
by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
option. The value selected by this boot parameter can
@@ -1487,6 +1617,8 @@
architectures force reset to be always executed
i8042.unlock [HW] Unlock (ignore) the keylock
i8042.kbdreset [HW] Reset device connected to KBD port
+ i8042.probe_defer
+ [HW] Allow deferred probing upon i8042 probe errors
i810= [HW,DRM]
@@ -1688,6 +1820,13 @@
initrd= [BOOT] Specify the location of the initial ramdisk
+ initrdmem= [KNL] Specify a physical address and size from which to
+ load the initrd. If an initrd is compiled in or
+ specified in the bootparams, it takes priority over this
+ setting.
+ Format: ss[KMG],nn[KMG]
+ Default is 0, 0
+
init_on_alloc= [MM] Fill newly allocated pages and heap objects with
zeroes.
Format: 0 | 1
@@ -1697,7 +1836,7 @@
Format: 0 | 1
Default set by CONFIG_INIT_ON_FREE_DEFAULT_ON.
- init_pkru= [x86] Specify the default memory protection keys rights
+ init_pkru= [X86] Specify the default memory protection keys rights
register contents for all processes. 0x55555554 by
default (disallow access to all but pkey 0). Can
override in debugfs after boot.
@@ -1705,7 +1844,7 @@
inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
Format: <irq>
- int_pln_enable [x86] Enable power limit notification interrupt
+ int_pln_enable [X86] Enable power limit notification interrupt
integrity_audit=[IMA]
Format: { "0" | "1" }
@@ -1723,7 +1862,7 @@
bypassed by not enabling DMAR with this option. In
this case, gfx device will use physical address for
DMA.
- forcedac [x86_64]
+ forcedac [X86-64]
With this option iommu will not optimize to look
for io virtual address below 32-bit forcing dual
address cycle on pci bus for cards supporting greater
@@ -1753,7 +1892,7 @@
provided by tboot because it makes the system
vulnerable to DMA attacks.
nobounce [Default off]
- Disable bounce buffer for unstrusted devices such as
+ Disable bounce buffer for untrusted devices such as
the Thunderbolt devices. This will treat the untrusted
devices as the trusted ones, hence might expose security
risks of DMA attacks.
@@ -1808,7 +1947,7 @@
strict regions from userspace.
relaxed
- iommu= [x86]
+ iommu= [X86]
off
force
noforce
@@ -1818,8 +1957,8 @@
merge
nomerge
soft
- pt [x86]
- nopt [x86]
+ pt [X86]
+ nopt [X86]
nobypass [PPC/POWERNV]
Disable IOMMU bypass, using IOMMU for PCI devices.
@@ -1842,7 +1981,7 @@
1 - Bypass the IOMMU for DMA.
unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
- io7= [HW] IO7 for Marvel based alpha systems
+ io7= [HW] IO7 for Marvel-based Alpha systems
See comment before marvel_specify_io7 in
arch/alpha/kernel/core_marvel.c.
@@ -1857,7 +1996,7 @@
No delay
ip= [IP_PNP]
- See Documentation/filesystems/nfs/nfsroot.txt.
+ See Documentation/admin-guide/nfs/nfsroot.rst.
ipcmni_extend [KNL] Extend the maximum number of unique System V
IPC identifiers from 32,768 to 16,777,216.
@@ -1934,27 +2073,49 @@
<cpu number> begins at 0 and the maximum value is
"number of CPUs in system - 1".
+ managed_irq
+
+ Isolate from being targeted by managed interrupts
+ which have an interrupt mask containing isolated
+ CPUs. The affinity of managed interrupts is
+ handled by the kernel and cannot be changed via
+ the /proc/irq/* interfaces.
+
+ This isolation is best effort and only effective
+ if the automatically assigned interrupt mask of a
+ device queue contains isolated and housekeeping
+ CPUs. If housekeeping CPUs are online then such
+ interrupts are directed to the housekeeping CPU
+ so that IO submitted on the housekeeping CPU
+ cannot disturb the isolated CPU.
+
+ If a queue's affinity mask contains only isolated
+ CPUs then this parameter has no effect on the
+ interrupt routing decision, though interrupts are
+ only delivered when tasks running on those
+ isolated CPUs submit IO. IO submitted on
+ housekeeping CPUs has no influence on those
+ queues.
+
The format of <cpu-list> is described above.
-
-
iucv= [HW,NET]
- ivrs_ioapic [HW,X86_64]
+ ivrs_ioapic [HW,X86-64]
Provide an override to the IOAPIC-ID<->DEVICE-ID
mapping provided in the IVRS ACPI table. For
example, to map IOAPIC-ID decimal 10 to
PCI device 00:14.0 write the parameter as:
ivrs_ioapic[10]=00:14.0
- ivrs_hpet [HW,X86_64]
+ ivrs_hpet [HW,X86-64]
Provide an override to the HPET-ID<->DEVICE-ID
mapping provided in the IVRS ACPI table. For
example, to map HPET-ID decimal 0 to
PCI device 00:14.0 write the parameter as:
ivrs_hpet[0]=00:14.0
- ivrs_acpihid [HW,X86_64]
+ ivrs_acpihid [HW,X86-64]
Provide an override to the ACPI-HID:UID<->DEVICE-ID
mapping provided in the IVRS ACPI table. For
example, to map UART-HID:UID AMD0020:0 to
@@ -2023,10 +2184,25 @@
kms, kbd format: kms,kbd
kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
+ kgdboc_earlycon= [KGDB,HW]
+ If the boot console provides the ability to read
+ characters and can work in polling mode, you can use
+ this parameter to tell kgdb to use it as a backend
+ until the normal console is registered. Intended to
+ be used together with the kgdboc parameter which
+ specifies the normal console to transition to.
+
+ The name of the early console should be specified
+ as the value of this parameter. Note that the name of
+ the early console might be different than the tty
+ name passed to kgdboc. It's OK to leave the value
+ blank and the first boot console that implements
+ read() will be picked.
+
kgdbwait [KGDB] Stop kernel execution and enter the
kernel debugger at the earliest opportunity.
- kmac= [MIPS] korina ethernet MAC address.
+ kmac= [MIPS] Korina ethernet MAC address.
Configure the RouterBoard 532 series on-chip
Ethernet adapter MAC address.
@@ -2107,13 +2283,25 @@
[KVM,ARM] Allow use of GICv4 for direct injection of
LPIs.
+ kvm_cma_resv_ratio=n [PPC]
+ Reserves given percentage from system memory area for
+ contiguous memory allocation for KVM hash pagetable
+ allocation.
+ By default it reserves 5% of total system memory.
+ Format: <integer>
+ Default: 5
+
kvm-intel.ept= [KVM,Intel] Disable extended page tables
(virtualized MMU) support on capable Intel chips.
Default is 1 (enabled)
kvm-intel.emulate_invalid_guest_state=
- [KVM,Intel] Enable emulation of invalid guest states
- Default is 0 (disabled)
+ [KVM,Intel] Disable emulation of invalid guest state.
+ Ignored if kvm-intel.enable_unrestricted_guest=1, as
+ guest state is never invalid for unrestricted guests.
+ This param doesn't apply to nested guests (L2), as KVM
+ never emulates invalid L2 guest state.
+ Default is 1 (enabled)
kvm-intel.flexpriority=
[KVM,Intel] Disable FlexPriority feature (TPR shadow).
@@ -2216,9 +2404,10 @@
lapic [X86-32,APIC] Enable the local APIC even if BIOS
disabled it.
- lapic= [x86,APIC] "notscdeadline" Do not use TSC deadline
+ lapic= [X86,APIC] Do not use TSC deadline
value for LAPIC timer one-shot implementation. Default
back to the programmable timer unit in the LAPIC.
+ Format: notscdeadline
lapic_timer_c2_ok [X86,APIC] trust the local apic timer
in C2 power state.
@@ -2290,8 +2479,7 @@
memblock=debug [KNL] Enable memblock debug messages.
- load_ramdisk= [RAM] List of ramdisks to load from floppy
- See Documentation/admin-guide/blockdev/ramdisk.rst.
+ load_ramdisk= [RAM] [Deprecated]
lockd.nlm_grace_period=P [NFS] Assign grace period.
Format: <integer>
@@ -2428,8 +2616,8 @@
(machvec) in a generic kernel.
Example: machvec=hpzx1
- machtype= [Loongson] Share the same kernel image file between different
- yeeloong laptop.
+ machtype= [Loongson] Share the same kernel image file between
+ different yeeloong laptops.
Example: machtype=lemote-yeeloong-2f-7inch
max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
@@ -2495,13 +2683,22 @@
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.
+ Amount of memory to be used in cases as follows:
+
+ 1 for test;
+ 2 when the kernel is not able to see the whole system memory;
+ 3 memory that lies after 'mem=' boundary is excluded from
+ the hypervisor, then assigned to KVM guests.
+
[X86] Work as limiting max address. Use together
with memmap= to avoid physical address space collisions.
Without memmap= PCI devices could be placed at addresses
belonging to unused RAM.
+ Note that this only takes effects during boot time since
+ in above case 3, memory may need be hot added after boot
+ if system memory of hypervisor is not sufficient.
+
mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
memory.
@@ -2614,7 +2811,7 @@
See Documentation/admin-guide/pm/sleep-states.rst.
meye.*= [HW] Set MotionEye Camera parameters
- See Documentation/media/v4l-drivers/meye.rst.
+ See Documentation/admin-guide/media/meye.rst.
mfgpt_irq= [IA-32] Specify the IRQ to use for the
Multi-Function General Purpose Timers on AMD Geode
@@ -2649,7 +2846,7 @@
touchscreen support is not enabled in the mainstream
kernel as of 2.6.30, a preliminary port can be found
in the "bleeding edge" mini2440 support kernel at
- http://repo.or.cz/w/linux-2.6/mini2440.git
+ https://repo.or.cz/w/linux-2.6/mini2440.git
mitigations=
[X86,PPC,S390,ARM64] Control optional mitigations for
@@ -2807,13 +3004,13 @@
Default value is 0.
nfsaddrs= [NFS] Deprecated. Use ip= instead.
- See Documentation/filesystems/nfs/nfsroot.txt.
+ See Documentation/admin-guide/nfs/nfsroot.rst.
nfsroot= [NFS] nfs root filesystem for disk-less boxes.
- See Documentation/filesystems/nfs/nfsroot.txt.
+ See Documentation/admin-guide/nfs/nfsroot.rst.
nfsrootdebug [NFS] enable nfsroot debugging messages.
- See Documentation/filesystems/nfs/nfsroot.txt.
+ See Documentation/admin-guide/nfs/nfsroot.rst.
nfs.callback_nr_threads=
[NFSv4] set the total number of threads that the
@@ -2912,6 +3109,10 @@
and gids from such clients. This is intended to ease
migration from NFSv2/v3.
+ nmi_backtrace.backtrace_idle [KNL]
+ Dump stacks even of idle CPUs in response to an
+ NMI stack-backtrace request.
+
nmi_debug= [KNL,SH] Specify one or more actions to take
when a NMI is triggered.
Format: [state][,regs][,debounce][,die]
@@ -2944,6 +3145,8 @@
no5lvl [X86-64] Disable 5-level paging mode. Forces
kernel to use 4-level paging instead.
+ nofsgsbase [X86] Disables FSGSBASE instructions.
+
no_console_suspend
[HW] Never suspend the console
Disable suspending of consoles during suspend and
@@ -3027,12 +3230,12 @@
register save and restore. The kernel will only save
legacy floating-point registers on task switch.
- nohugeiomap [KNL,x86,PPC] Disable kernel huge I/O mappings.
+ nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
nosmt [KNL,S390] Disable symmetric multithreading (SMT).
Equivalent to smt=1.
- [KNL,x86] Disable symmetric multithreading (SMT).
+ [KNL,X86] Disable symmetric multithreading (SMT).
nosmt=force: Force disable SMT, cannot be undone
via the sysfs control file.
@@ -3133,9 +3336,9 @@
[X86,PV_OPS] Disable paravirtualized VMware scheduler
clock and use the default one.
- no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting.
- steal time is computed, but won't influence scheduler
- behaviour
+ no-steal-acc [X86,PV_OPS,ARM64] Disable paravirtualized steal time
+ accounting. steal time is computed, but won't
+ influence scheduler behaviour
nolapic [X86-32,APIC] Do not enable or use the local APIC.
@@ -3245,7 +3448,7 @@
See Documentation/admin-guide/sysctl/vm.rst for details.
ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
- See Documentation/debugging-via-ohci1394.txt for more
+ See Documentation/core-api/debugging-via-ohci1394.rst for more
info.
olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
@@ -3317,6 +3520,19 @@
bit 4: print ftrace buffer
bit 5: print all printk messages in buffer
+ panic_on_taint= Bitmask for conditionally calling panic() in add_taint()
+ Format: <hex>[,nousertaint]
+ Hexadecimal bitmask representing the set of TAINT flags
+ that will cause the kernel to panic when add_taint() is
+ called with any of the flags in this set.
+ The optional switch "nousertaint" can be utilized to
+ prevent userspace forced crashes by writing to sysctl
+ /proc/sys/kernel/tainted any flagset matching with the
+ bitmask set on panic_on_taint.
+ See Documentation/admin-guide/tainted-kernels.rst for
+ extra details on the taint flags that users can pick
+ to compose the bitmask to assign to panic_on_taint.
+
panic_on_warn panic() instead of WARN(). Useful to cause kdump
on a WARN().
@@ -3542,8 +3758,15 @@
hpiosize=nn[KMG] The fixed amount of bus space which is
reserved for hotplug bridge's IO window.
Default size is 256 bytes.
+ hpmmiosize=nn[KMG] The fixed amount of bus space which is
+ reserved for hotplug bridge's MMIO window.
+ Default size is 2 megabytes.
+ hpmmioprefsize=nn[KMG] The fixed amount of bus space which is
+ reserved for hotplug bridge's MMIO_PREF window.
+ Default size is 2 megabytes.
hpmemsize=nn[KMG] The fixed amount of bus space which is
- reserved for hotplug bridge's memory window.
+ reserved for hotplug bridge's MMIO and
+ MMIO_PREF window.
Default size is 2 megabytes.
hpbussize=nn The minimum amount of additional bus numbers
reserved for buses below a hotplug bridge.
@@ -3578,6 +3801,8 @@
may put more devices in an IOMMU group.
force_floating [S390] Force usage of floating interrupts.
nomio [S390] Do not use MIO instructions.
+ norid [S390] ignore the RID field and force use of
+ one PCI domain per PCI function
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
Management.
@@ -3590,6 +3815,8 @@
even if the platform doesn't give the OS permission to
use them. This may cause conflicts if the platform
also tries to use these services.
+ dpc-native Use native PCIe service for DPC only. May
+ cause conflicts if firmware uses AER or DPC.
compat Disable native PCIe services (PME, AER, DPC, PCIe
hotplug).
@@ -3642,6 +3869,9 @@
Override pmtimer IOPort with a hex value.
e.g. pmtmr=0x508
+ pm_debug_messages [SUSPEND,KNL]
+ Enable suspend/resume debug messages during boot up.
+
pnp.debug=1 [PNP]
Enable PNP debug messages (depends on the
CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
@@ -3739,9 +3969,12 @@
Param: <number> - step/bucket size as a power of 2 for
statistical time based profiling.
- prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
- before loading.
- See Documentation/admin-guide/blockdev/ramdisk.rst.
+ prompt_ramdisk= [RAM] [Deprecated]
+
+ prot_virt= [S390] enable hosting protected virtual machines
+ isolated from the hypervisor (if hardware supports
+ that).
+ Format: <bool>
psi= [KNL] Enable or disable pressure stall information
tracking.
@@ -3765,7 +3998,7 @@
pt. [PARIDE]
See Documentation/admin-guide/blockdev/paride.rst.
- pti= [X86_64] Control Page Table Isolation of user and
+ pti= [X86-64] Control Page Table Isolation of user and
kernel address spaces. Disabling this feature
removes hardening, but improves performance of
system calls and interrupts.
@@ -3777,7 +4010,7 @@
Not specifying this option is equivalent to pti=auto.
- nopti [X86_64]
+ nopti [X86-64]
Equivalent to pti=off
pty.legacy_count=
@@ -3794,6 +4027,8 @@
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
See Documentation/admin-guide/blockdev/ramdisk.rst.
+ ramdisk_start= [RAM] RAM disk image start address
+
random.trust_cpu={on,off}
[KNL] Enable or disable trusting the use of the
CPU's random number generator (if available) to
@@ -3876,6 +4111,14 @@
latencies, which will choose a value aligned
with the appropriate hardware boundaries.
+ rcutree.rcu_min_cached_objs= [KNL]
+ Minimum number of objects which are cached and
+ maintained per one CPU. Object size is equal
+ to PAGE_SIZE. The cache allows to reduce the
+ pressure to page allocator, also it makes the
+ whole algorithm to behave better in low memory
+ condition.
+
rcutree.jiffies_till_first_fqs= [KNL]
Set delay from grace-period initialization to
first attempt to force quiescent states.
@@ -3928,6 +4171,15 @@
Set threshold of queued RCU callbacks below which
batch limiting is re-enabled.
+ rcutree.qovld= [KNL]
+ Set threshold of queued RCU callbacks beyond which
+ RCU's force-quiescent-state scan will aggressively
+ enlist help from cond_resched() and sched IPIs to
+ help CPUs more quickly reach quiescent states.
+ Set to less than zero to make this be set based
+ on rcutree.qhimark at boot time and to zero to
+ disable more aggressive help enlistment.
+
rcutree.rcu_idle_gp_delay= [KNL]
Set wakeup interval for idle CPUs that have
RCU callbacks (RCU_FAST_NO_HZ=y).
@@ -3945,33 +4197,55 @@
This wake_up() will be accompanied by a
WARN_ONCE() splat and an ftrace_dump().
+ rcutree.rcu_unlock_delay= [KNL]
+ In CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels,
+ this specifies an rcu_read_unlock()-time delay
+ in microseconds. This defaults to zero.
+ Larger delays increase the probability of
+ catching RCU pointer leaks, that is, buggy use
+ of RCU-protected pointers after the relevant
+ rcu_read_unlock() has completed.
+
rcutree.sysrq_rcu= [KNL]
Commandeer a sysrq key to dump out Tree RCU's
rcu_node tree with an eye towards determining
why a new grace period has not yet started.
- rcuperf.gp_async= [KNL]
+ rcuscale.gp_async= [KNL]
Measure performance of asynchronous
grace-period primitives such as call_rcu().
- rcuperf.gp_async_max= [KNL]
+ rcuscale.gp_async_max= [KNL]
Specify the maximum number of outstanding
callbacks per writer thread. When a writer
thread exceeds this limit, it invokes the
corresponding flavor of rcu_barrier() to allow
previously posted callbacks to drain.
- rcuperf.gp_exp= [KNL]
+ rcuscale.gp_exp= [KNL]
Measure performance of expedited synchronous
grace-period primitives.
- rcuperf.holdoff= [KNL]
+ rcuscale.holdoff= [KNL]
Set test-start holdoff period. The purpose of
this parameter is to delay the start of the
test until boot completes in order to avoid
interference.
- rcuperf.nreaders= [KNL]
+ rcuscale.kfree_rcu_test= [KNL]
+ Set to measure performance of kfree_rcu() flooding.
+
+ rcuscale.kfree_nthreads= [KNL]
+ The number of threads running loops of kfree_rcu().
+
+ rcuscale.kfree_alloc_num= [KNL]
+ Number of allocations and frees done in an iteration.
+
+ rcuscale.kfree_loops= [KNL]
+ Number of loops doing rcuscale.kfree_alloc_num number
+ of allocations and frees.
+
+ rcuscale.nreaders= [KNL]
Set number of RCU readers. The value -1 selects
N, where N is the number of CPUs. A value
"n" less than -1 selects N-n+1, where N is again
@@ -3980,23 +4254,23 @@
A value of "n" less than or equal to -N selects
a single reader.
- rcuperf.nwriters= [KNL]
+ rcuscale.nwriters= [KNL]
Set number of RCU writers. The values operate
- the same as for rcuperf.nreaders.
+ the same as for rcuscale.nreaders.
N, where N is the number of CPUs
- rcuperf.perf_type= [KNL]
+ rcuscale.perf_type= [KNL]
Specify the RCU implementation to test.
- rcuperf.shutdown= [KNL]
+ rcuscale.shutdown= [KNL]
Shut the system down after performance tests
complete. This is useful for hands-off automated
testing.
- rcuperf.verbose= [KNL]
+ rcuscale.verbose= [KNL]
Enable additional printk() statements.
- rcuperf.writer_holdoff= [KNL]
+ rcuscale.writer_holdoff= [KNL]
Write-side holdoff between grace periods,
in microseconds. The default of zero says
no holdoff.
@@ -4049,6 +4323,18 @@
are zero, rcutorture acts as if is interpreted
they are all non-zero.
+ rcutorture.irqreader= [KNL]
+ Run RCU readers from irq handlers, or, more
+ accurately, from a timer handler. Not all RCU
+ flavors take kindly to this sort of thing.
+
+ rcutorture.leakpointer= [KNL]
+ Leak an RCU-protected pointer out of the reader.
+ This can of course result in splats, and is
+ intended to test the ability of things like
+ CONFIG_RCU_STRICT_GRACE_PERIOD=y to detect
+ such leaks.
+
rcutorture.n_barrier_cbs= [KNL]
Set callbacks/threads for rcu_barrier() testing.
@@ -4074,6 +4360,20 @@
Set time (jiffies) between CPU-hotplug operations,
or zero to disable CPU-hotplug testing.
+ rcutorture.read_exit= [KNL]
+ Set the number of read-then-exit kthreads used
+ to test the interaction of RCU updaters and
+ task-exit processing.
+
+ rcutorture.read_exit_burst= [KNL]
+ The number of times in a given read-then-exit
+ episode that a set of read-then-exit kthreads
+ is spawned.
+
+ rcutorture.read_exit_delay= [KNL]
+ The delay, in seconds, between successive
+ read-then-exit testing episodes.
+
rcutorture.shuffle_interval= [KNL]
Set task-shuffle interval (s). Shuffling tasks
allows some CPUs to go into dyntick-idle mode
@@ -4087,12 +4387,24 @@
Duration of CPU stall (s) to test RCU CPU stall
warnings, zero to disable.
+ rcutorture.stall_cpu_block= [KNL]
+ Sleep while stalling if set. This will result
+ in warnings from preemptible RCU in addition
+ to any other stall-related activity.
+
rcutorture.stall_cpu_holdoff= [KNL]
Time to wait (s) after boot before inducing stall.
rcutorture.stall_cpu_irqsoff= [KNL]
Disable interrupts while stalling if set.
+ rcutorture.stall_gp_kthread= [KNL]
+ Duration (s) of forced sleep within RCU
+ grace-period kthread to test RCU CPU stall
+ warnings, zero to disable. If both stall_cpu
+ and stall_gp_kthread are specified, the
+ kthread is starved first, then the CPU.
+
rcutorture.stat_interval= [KNL]
Time (s) between statistics printk()s.
@@ -4130,6 +4442,12 @@
rcupdate.rcu_cpu_stall_suppress= [KNL]
Suppress RCU CPU stall warning messages.
+ rcupdate.rcu_cpu_stall_suppress_at_boot= [KNL]
+ Suppress RCU CPU stall warning messages and
+ rcutorture writer stall warnings that occur
+ during early boot, that is, during the time
+ before the init task is spawned.
+
rcupdate.rcu_cpu_stall_timeout= [KNL]
Set timeout for RCU CPU stall warning messages.
@@ -4157,6 +4475,13 @@
only normal grace-period primitives. No effect
on CONFIG_TINY_RCU kernels.
+ rcupdate.rcu_task_ipi_delay= [KNL]
+ Set time in jiffies during which RCU tasks will
+ avoid sending IPIs, starting with the beginning
+ of a given grace period. Setting a large
+ number avoids disturbing real-time workloads,
+ but lengthens grace periods.
+
rcupdate.rcu_task_stall_timeout= [KNL]
Set timeout in jiffies for RCU task stall warning
messages. Disable with a value less than or equal
@@ -4198,6 +4523,45 @@
reboot_cpu is s[mp]#### with #### being the processor
to be used for rebooting.
+ refscale.holdoff= [KNL]
+ Set test-start holdoff period. The purpose of
+ this parameter is to delay the start of the
+ test until boot completes in order to avoid
+ interference.
+
+ refscale.loops= [KNL]
+ Set the number of loops over the synchronization
+ primitive under test. Increasing this number
+ reduces noise due to loop start/end overhead,
+ but the default has already reduced the per-pass
+ noise to a handful of picoseconds on ca. 2020
+ x86 laptops.
+
+ refscale.nreaders= [KNL]
+ Set number of readers. The default value of -1
+ selects N, where N is roughly 75% of the number
+ of CPUs. A value of zero is an interesting choice.
+
+ refscale.nruns= [KNL]
+ Set number of runs, each of which is dumped onto
+ the console log.
+
+ refscale.readdelay= [KNL]
+ Set the read-side critical-section duration,
+ measured in microseconds.
+
+ refscale.scale_type= [KNL]
+ Specify the read-protection implementation to test.
+
+ refscale.shutdown= [KNL]
+ Shut down the system at the end of the performance
+ test. This defaults to 1 (shut it down) when
+ refscale is built into the kernel and to 0 (leave
+ it running) when refscale is built as a module.
+
+ refscale.verbose= [KNL]
+ Enable additional printk() statements.
+
relax_domain_level=
[KNL, SMP] Set scheduler's default relax_domain_level.
See Documentation/admin-guide/cgroup-v1/cpusets.rst.
@@ -4323,6 +4687,114 @@
incurs a small amount of overhead in the scheduler
but is useful for debugging and performance tuning.
+ sched_thermal_decay_shift=
+ [KNL, SMP] Set a decay shift for scheduler thermal
+ pressure signal. Thermal pressure signal follows the
+ default decay period of other scheduler pelt
+ signals(usually 32 ms but configurable). Setting
+ sched_thermal_decay_shift will left shift the decay
+ period for the thermal pressure signal by the shift
+ value.
+ i.e. with the default pelt decay period of 32 ms
+ sched_thermal_decay_shift thermal pressure decay pr
+ 1 64 ms
+ 2 128 ms
+ and so on.
+ Format: integer between 0 and 10
+ Default is 0.
+
+ scftorture.holdoff= [KNL]
+ Number of seconds to hold off before starting
+ test. Defaults to zero for module insertion and
+ to 10 seconds for built-in smp_call_function()
+ tests.
+
+ scftorture.longwait= [KNL]
+ Request ridiculously long waits randomly selected
+ up to the chosen limit in seconds. Zero (the
+ default) disables this feature. Please note
+ that requesting even small non-zero numbers of
+ seconds can result in RCU CPU stall warnings,
+ softlockup complaints, and so on.
+
+ scftorture.nthreads= [KNL]
+ Number of kthreads to spawn to invoke the
+ smp_call_function() family of functions.
+ The default of -1 specifies a number of kthreads
+ equal to the number of CPUs.
+
+ scftorture.onoff_holdoff= [KNL]
+ Number seconds to wait after the start of the
+ test before initiating CPU-hotplug operations.
+
+ scftorture.onoff_interval= [KNL]
+ Number seconds to wait between successive
+ CPU-hotplug operations. Specifying zero (which
+ is the default) disables CPU-hotplug operations.
+
+ scftorture.shutdown_secs= [KNL]
+ The number of seconds following the start of the
+ test after which to shut down the system. The
+ default of zero avoids shutting down the system.
+ Non-zero values are useful for automated tests.
+
+ scftorture.stat_interval= [KNL]
+ The number of seconds between outputting the
+ current test statistics to the console. A value
+ of zero disables statistics output.
+
+ scftorture.stutter_cpus= [KNL]
+ The number of jiffies to wait between each change
+ to the set of CPUs under test.
+
+ scftorture.use_cpus_read_lock= [KNL]
+ Use use_cpus_read_lock() instead of the default
+ preempt_disable() to disable CPU hotplug
+ while invoking one of the smp_call_function*()
+ functions.
+
+ scftorture.verbose= [KNL]
+ Enable additional printk() statements.
+
+ scftorture.weight_single= [KNL]
+ The probability weighting to use for the
+ smp_call_function_single() function with a zero
+ "wait" parameter. A value of -1 selects the
+ default if all other weights are -1. However,
+ if at least one weight has some other value, a
+ value of -1 will instead select a weight of zero.
+
+ scftorture.weight_single_wait= [KNL]
+ The probability weighting to use for the
+ smp_call_function_single() function with a
+ non-zero "wait" parameter. See weight_single.
+
+ scftorture.weight_many= [KNL]
+ The probability weighting to use for the
+ smp_call_function_many() function with a zero
+ "wait" parameter. See weight_single.
+ Note well that setting a high probability for
+ this weighting can place serious IPI load
+ on the system.
+
+ scftorture.weight_many_wait= [KNL]
+ The probability weighting to use for the
+ smp_call_function_many() function with a
+ non-zero "wait" parameter. See weight_single
+ and weight_many.
+
+ scftorture.weight_all= [KNL]
+ The probability weighting to use for the
+ smp_call_function_all() function with a zero
+ "wait" parameter. See weight_single and
+ weight_many.
+
+ scftorture.weight_all_wait= [KNL]
+ The probability weighting to use for the
+ smp_call_function_all() function with a
+ non-zero "wait" parameter. See weight_single
+ and weight_many.
+
skew_tick= [KNL] Offset the periodic timer tick per cpu to mitigate
xtime_lock contention on larger systems, and/or RCU lock
contention on all systems with CONFIG_MAXSMP set.
@@ -4341,9 +4813,7 @@
See security/selinux/Kconfig help text.
0 -- disable.
1 -- enable.
- Default value is set via kernel config option.
- If enabled at boot time, /selinux/disable can be used
- later to disable prior to initial policy load.
+ Default value is 1.
apparmor= [APPARMOR] Disable or enable AppArmor at boot time
Format: { "0" | "1" }
@@ -4381,7 +4851,7 @@
fragmentation. Defaults to 1 for systems with
more than 32MB of RAM, 0 otherwise.
- slub_debug[=options[,slabs]] [MM, SLUB]
+ slub_debug[=options[,slabs][;[options[,slabs]]...] [MM, SLUB]
Enabling slub_debug allows one to determine the
culprit if slab objects become corrupted. Enabling
slub_debug can create guard zones around objects and
@@ -4444,18 +4914,18 @@
softlockup_panic=
[KNL] Should the soft-lockup detector generate panics.
- Format: <integer>
+ Format: 0 | 1
- A nonzero value instructs the soft-lockup detector
- to panic the machine when a soft-lockup occurs. This
- is also controlled by CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC
- which is the respective build-time switch to that
- functionality.
+ A value of 1 instructs the soft-lockup detector
+ to panic the machine when a soft-lockup occurs. It is
+ also controlled by the kernel.softlockup_panic sysctl
+ and CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC, which is the
+ respective build-time switch to that functionality.
softlockup_all_cpu_backtrace=
[KNL] Should the soft-lockup detector generate
backtraces on all cpus.
- Format: <integer>
+ Format: 0 | 1
sonypi.*= [HW] Sony Programmable I/O Control Device driver
See Documentation/admin-guide/laptops/sonypi.rst
@@ -4487,8 +4957,12 @@
Specific mitigations can also be selected manually:
retpoline - replace indirect branches
- retpoline,generic - google's original retpoline
- retpoline,amd - AMD-specific minimal thunk
+ retpoline,generic - Retpolines
+ retpoline,lfence - LFENCE; indirect branch
+ retpoline,amd - alias for retpoline,lfence
+ eibrs - enhanced IBRS
+ eibrs,retpoline - enhanced IBRS + Retpolines
+ eibrs,lfence - enhanced IBRS + LFENCE
Not specifying this option is equivalent to
spectre_v2=auto.
@@ -4592,6 +5066,28 @@
spia_pedr=
spia_peddr=
+ split_lock_detect=
+ [X86] Enable split lock detection
+
+ When enabled (and if hardware support is present), atomic
+ instructions that access data across cache line
+ boundaries will result in an alignment check exception.
+
+ off - not enabled
+
+ warn - the kernel will emit rate limited warnings
+ about applications triggering the #AC
+ exception. This mode is the default on CPUs
+ that supports split lock detection.
+
+ fatal - the kernel will send SIGBUS to applications
+ that trigger the #AC exception.
+
+ If an #AC exception is hit in the kernel or in
+ firmware (i.e. not while executing in user mode)
+ the kernel will oops in either "warn" or "fatal"
+ mode.
+
srbds= [X86,INTEL]
Control the Special Register Buffer Data Sampling
(SRBDS) mitigation.
@@ -4746,6 +5242,15 @@
switches= [HW,M68k]
+ sysctl.*= [KNL]
+ Set a sysctl parameter, right before loading the init
+ process, as if the value was written to the respective
+ /proc/sys/... file. Both '.' and '/' are recognized as
+ separators. Unrecognized parameters and invalid values
+ are reported in the kernel log. Sysctls registered
+ later by a loaded module cannot be set this way.
+ Example: sysctl.vm.swappiness=40
+
sysfs.deprecated=0|1 [KNL]
Enable/disable old style sysfs layout for old udev
on older distributions. When this option is enabled
@@ -4765,7 +5270,7 @@
Set the number of tcp_metrics_hash slots.
Default value is 8192 or 16384 depending on total
ram pages. This is used to specify the TCP metrics
- cache size. See Documentation/networking/ip-sysctl.txt
+ cache size. See Documentation/networking/ip-sysctl.rst
"tcp_no_metrics_save" section for more details.
tdfx= [HW,DRM]
@@ -4824,6 +5329,17 @@
topology updates sent by the hypervisor to this
LPAR.
+ torture.disable_onoff_at_boot= [KNL]
+ Prevent the CPU-hotplug component of torturing
+ until after init has spawned.
+
+ torture.ftrace_dump_at_shutdown= [KNL]
+ Dump the ftrace buffer at torture-test shutdown,
+ even if there were no errors. This can be a
+ very costly operation when many torture tests
+ are running concurrently, especially on systems
+ with rotating-rust storage.
+
tp720= [HW,PS2]
tpm_suspend_pcr=[HW,TPM]
@@ -4918,6 +5434,12 @@
interruptions from clocksource watchdog are not
acceptable).
+ tsc_early_khz= [X86] Skip early TSC calibration and use the given
+ value instead. Useful when the early TSC frequency discovery
+ procedure is not reliable, such as on overclocked systems
+ with CPUID.16h support and partial CPUID.15h support.
+ Format: <unsigned int>
+
tsx= [X86] Control Transactional Synchronization
Extensions (TSX) feature in Intel processors that
support TSX control.
@@ -5449,8 +5971,9 @@
panic() code such as dumping handler.
xen_nopvspin [X86,XEN]
- Disables the ticketlock slowpath using Xen PV
- optimizations.
+ Disables the qspinlock slowpath using Xen PV optimizations.
+ This parameter is obsoleted by "nopvspin" parameter, which
+ has equivalent effect for XEN platform.
xen_nopv [X86]
Disables the PV optimizations forcing the HVM guest to
@@ -5475,10 +5998,12 @@
improve timer resolution at the expense of processing
more timer interrupts.
- nopv= [X86,XEN,KVM,HYPER_V,VMWARE]
- Disables the PV optimizations forcing the guest to run
- as generic guest with no PV drivers. Currently support
- XEN HVM, KVM, HYPER_V and VMWARE guest.
+ xen.balloon_boot_timeout= [XEN]
+ The time (in seconds) to wait before giving up to boot
+ in case initial ballooning fails to free enough memory.
+ Applies only when running as HVM or PVH guest and
+ started with less memory configured than allowed at
+ max. Default is 180.
xen.event_eoi_delay= [XEN]
How long to delay EOI handling in case of event
@@ -5488,6 +6013,23 @@
After which time (jiffies) the event handling loop
should start to delay EOI handling. Default is 2.
+ xen.fifo_events= [XEN]
+ Boolean parameter to disable using fifo event handling
+ even if available. Normally fifo event handling is
+ preferred over the 2-level event handling, as it is
+ fairer and the number of possible event channels is
+ much higher. Default is on (use fifo events).
+
+ nopv= [X86,XEN,KVM,HYPER_V,VMWARE]
+ Disables the PV optimizations forcing the guest to run
+ as generic guest with no PV drivers. Currently support
+ XEN HVM, KVM, HYPER_V and VMWARE guest.
+
+ nopvspin [X86,XEN,KVM]
+ Disables the qspinlock slow path using PV optimizations
+ which allow the hypervisor to 'idle' the guest on lock
+ contention.
+
xirc2ps_cs= [NET,PCMCIA]
Format:
<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]