diff options
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 117 |
1 files changed, 55 insertions, 62 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 500cfa776225..740ca2bc2822 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -12,7 +12,7 @@ acpi= [HW,ACPI,X86,ARM64,RISCV64,EARLY] Advanced Configuration and Power Interface Format: { force | on | off | strict | noirq | rsdt | - copy_dsdt } + copy_dsdt | nospcr } force -- enable ACPI if default was off on -- enable ACPI but allow fallback to DT [arm64,riscv64] off -- disable ACPI if default was on @@ -21,8 +21,12 @@ strictly ACPI specification compliant. rsdt -- prefer RSDT over (default) XSDT copy_dsdt -- copy DSDT to memory - For ARM64 and RISCV64, ONLY "acpi=off", "acpi=on" or - "acpi=force" are available + nospcr -- disable console in ACPI SPCR table as + default _serial_ console on ARM64 + For ARM64, ONLY "acpi=off", "acpi=on", "acpi=force" or + "acpi=nospcr" are available + For RISCV64, ONLY "acpi=off", "acpi=on" or "acpi=force" + are available See also Documentation/power/runtime_pm.rst, pci=noacpi @@ -788,25 +792,6 @@ Documentation/networking/netconsole.rst for an alternative. - <DEVNAME>:<n>.<n>[,options] - Use the specified serial port on the serial core bus. - The addressing uses DEVNAME of the physical serial port - device, followed by the serial core controller instance, - and the serial port instance. The options are the same - as documented for the ttyS addressing above. - - The mapping of the serial ports to the tty instances - can be viewed with: - - $ ls -d /sys/bus/serial-base/devices/*:*.*/tty/* - /sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0 - - In the above example, the console can be addressed with - console=00:04:0.0. Note that a console addressed this - way will only get added when the related device driver - is ready. The use of an earlycon parameter in addition to - the console may be desired for console output early on. - uart[8250],io,<addr>[,options] uart[8250],mmio,<addr>[,options] uart[8250],mmio16,<addr>[,options] @@ -1450,27 +1435,6 @@ you are really sure that your UEFI does sane gc and fulfills the spec otherwise your board may brick. - efi_fake_mem= nn[KMG]@ss[KMG]:aa[,nn[KMG]@ss[KMG]:aa,..] [EFI,X86,EARLY] - Add arbitrary attribute to specific memory range by - 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 features. For example, you can do debugging of - Address Range Mirroring feature even if your box - 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 multiple variables with the same name but with different @@ -1921,6 +1885,28 @@ Format: <bus_id>,<clkrate> + i2c_touchscreen_props= [HW,ACPI,X86] + Set device-properties for ACPI-enumerated I2C-attached + touchscreen, to e.g. fix coordinates of upside-down + mounted touchscreens. If you need this option please + submit a drivers/platform/x86/touchscreen_dmi.c patch + adding a DMI quirk for this. + + Format: + <ACPI_HW_ID>:<prop_name>=<val>[:prop_name=val][:...] + Where <val> is one of: + Omit "=<val>" entirely Set a boolean device-property + Unsigned number Set a u32 device-property + Anything else Set a string device-property + + Examples (split over multiple lines): + i2c_touchscreen_props=GDIX1001:touchscreen-inverted-x: + touchscreen-inverted-y + + i2c_touchscreen_props=MSSL1680:touchscreen-size-x=1920: + touchscreen-size-y=1080:touchscreen-inverted-y: + firmware-name=gsl1680-vendor-model.fw:silead,home-button + i8042.debug [HW] Toggle i8042 debug mode i8042.unmask_kbd_data [HW] Enable printing of interrupt data from the KBD port @@ -2170,12 +2156,6 @@ Format: 0 | 1 Default set by CONFIG_INIT_ON_FREE_DEFAULT_ON. - init_mlocked_on_free= [MM] Fill freed userspace memory with zeroes if - it was mlock'ed and not explicitly munlock'ed - afterwards. - Format: 0 | 1 - Default set by CONFIG_INIT_MLOCKED_ON_FREE_DEFAULT_ON - 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 @@ -3407,10 +3387,6 @@ deep - Suspend-To-RAM or equivalent (if supported) See Documentation/admin-guide/pm/sleep-states.rst. - mfgpt_irq= [IA-32] Specify the IRQ to use for the - Multi-Function General Purpose Timers on AMD Geode - platforms. - mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when the BIOS has incorrectly applied a workaround. TinyBIOS version 0.98 is known to be affected, 0.99 fixes the @@ -4752,7 +4728,9 @@ none - Limited to cond_resched() calls voluntary - Limited to cond_resched() and might_sleep() calls full - Any section that isn't explicitly preempt disabled - can be preempted anytime. + can be preempted anytime. Tasks will also yield + contended spinlocks (if the critical section isn't + explicitly preempt disabled beyond the lock itself). print-fatal-signals= [KNL] debug: print fatal signals @@ -5018,6 +4996,14 @@ the ->nocb_bypass queue. The definition of "too many" is supplied by this kernel boot parameter. + rcutree.nohz_full_patience_delay= [KNL] + On callback-offloaded (rcu_nocbs) CPUs, avoid + disturbing RCU unless the grace period has + reached the specified age in milliseconds. + Defaults to zero. Large values will be capped + at five seconds. All values will be rounded down + to the nearest value representable by jiffies. + rcutree.qhimark= [KNL] Set threshold of queued RCU callbacks beyond which batch limiting is disabled. @@ -6120,9 +6106,15 @@ deployment of the HW BHI control and the SW BHB clearing sequence. - on - (default) Enable the HW or SW mitigation - as needed. - off - Disable the mitigation. + on - (default) Enable the HW or SW mitigation as + needed. This protects the kernel from + both syscalls and VMs. + vmexit - On systems which don't have the HW mitigation + available, enable the SW mitigation on vmexit + ONLY. On such systems, the host kernel is + protected from VM-originated BHI attacks, but + may still be vulnerable to syscall attacks. + off - Disable the mitigation. spectre_v2= [X86,EARLY] Control mitigation of Spectre variant 2 (indirect branch speculation) vulnerability. @@ -7430,17 +7422,18 @@ Crash from Xen panic notifier, without executing late panic() code such as dumping handler. + xen_mc_debug [X86,XEN,EARLY] + Enable multicall debugging when running as a Xen PV guest. + Enabling this feature will reduce performance a little + bit, so it should only be enabled for obtaining extended + debug data in case of multicall errors. + xen_msr_safe= [X86,XEN,EARLY] Format: <bool> Select whether to always use non-faulting (safe) MSR access functions when running as Xen PV guest. The default value is controlled by CONFIG_XEN_PV_MSR_SAFE. - xen_nopvspin [X86,XEN,EARLY] - 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 run as generic HVM guest with no PV drivers. |