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| author | Steven Rostedt <rostedt@goodmis.org> | 2024-08-14 16:56:42 -0400 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2024-08-14 16:59:28 -0400 |
| commit | ee057c8c194b9283f4137b253b70e292693a39f0 (patch) | |
| tree | 4ee9868bfc432e0b1230016cd316468719f0b477 /Documentation/admin-guide/kernel-parameters.txt | |
| parent | b96c312551b241bc17226c5347c6d6b38a1efd3e (diff) | |
| parent | 7c626ce4bae1ac14f60076d00eafe71af30450ba (diff) | |
| download | lwn-ee057c8c194b9283f4137b253b70e292693a39f0.tar.gz lwn-ee057c8c194b9283f4137b253b70e292693a39f0.zip | |
Merge tag 'v6.11-rc3' into trace/ring-buffer/core
The "reserve_mem" kernel command line parameter has been pulled into
v6.11. Merge the latest -rc3 to allow the persistent ring buffer memory to
be able to be mapped at the address specified by the "reserve_mem" command
line parameter.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 257 |
1 files changed, 125 insertions, 132 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index ff26b6094e79..35b592823338 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 @@ -1450,27 +1454,6 @@ 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 @@ -1778,8 +1761,6 @@ for 64-bit NUMA, off otherwise. Format: 0 | 1 (for off | on) - hcl= [IA-64] SGI's Hardware Graph compatibility layer - hd= [EIDE] (E)IDE hard drive subsystem geometry Format: <cyl>,<head>,<sect> @@ -2022,7 +2003,7 @@ for the device. By default it is set to false (0). ieee754= [MIPS] Select IEEE Std 754 conformance mode - Format: { strict | legacy | 2008 | relaxed } + Format: { strict | legacy | 2008 | relaxed | emulated } Default: strict Choose which programs will be accepted for execution @@ -2042,6 +2023,8 @@ by the FPU relaxed accept any binaries regardless of whether supported by the FPU + emulated accept any binaries but enable FPU emulator + if binary mode is unsupported by the FPU. The FPU emulator is always able to support both NaN encodings, so if no FPU hardware is present or it has @@ -2192,12 +2175,6 @@ 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 @@ -2544,7 +2521,7 @@ keepinitrd [HW,ARM] See retain_initrd. - kernelcore= [KNL,X86,IA-64,PPC,EARLY] + kernelcore= [KNL,X86,PPC,EARLY] Format: nn[KMGTPE] | nn% | "mirror" This parameter specifies the amount of memory usable by the kernel for non-movable allocations. The requested @@ -2745,6 +2722,24 @@ [KVM,ARM,EARLY] Allow use of GICv4 for direct injection of LPIs. + kvm-arm.wfe_trap_policy= + [KVM,ARM] Control when to set WFE instruction trap for + KVM VMs. Traps are allowed but not guaranteed by the + CPU architecture. + + trap: set WFE instruction trap + + notrap: clear WFE instruction trap + + kvm-arm.wfi_trap_policy= + [KVM,ARM] Control when to set WFI instruction trap for + KVM VMs. Traps are allowed but not guaranteed by the + CPU architecture. + + trap: set WFI instruction trap + + notrap: clear WFI instruction trap + kvm_cma_resv_ratio=n [PPC,EARLY] Reserves given percentage from system memory area for contiguous memory allocation for KVM hash pagetable @@ -3184,26 +3179,16 @@ unlikely, in the extreme case this might damage your hardware. - ltpc= [NET] - Format: <io>,<irq>,<dma> - lsm.debug [SECURITY] Enable LSM initialization debugging output. lsm=lsm1,...,lsmN [SECURITY] Choose order of LSM initialization. This overrides CONFIG_LSM, and the "security=" parameter. - machvec= [IA-64] Force the use of a particular machine-vector - (machvec) in a generic kernel. - Example: machvec=hpzx1 - machtype= [Loongson] Share the same kernel image file between different yeeloong laptops. Example: machtype=lemote-yeeloong-2f-7inch - max_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory greater - than or equal to this physical address is ignored. - maxcpus= [SMP,EARLY] Maximum number of processors that an SMP kernel will bring up during bootup. maxcpus=n : n >= 0 limits the kernel to bring up 'n' processors. Surely after @@ -3429,10 +3414,6 @@ 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 @@ -3445,9 +3426,6 @@ Enable or disable the microcode minimal revision enforcement for the runtime microcode loader. - min_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory below this - physical address is ignored. - mini2440= [ARM,HW,KNL] Format:[0..2][b][c][t] Default: "0tb" @@ -3612,7 +3590,7 @@ mousedev.yres= [MOUSE] Vertical screen resolution, used for devices reporting absolute coordinates, such as tablets - movablecore= [KNL,X86,IA-64,PPC,EARLY] + movablecore= [KNL,X86,PPC,EARLY] Format: nn[KMGTPE] | nn% This parameter is the complement to kernelcore=, it specifies the amount of memory used for migratable @@ -3638,11 +3616,6 @@ mtdparts= [MTD] See drivers/mtd/parsers/cmdlinepart.c - mtdset= [ARM] - ARM/S3C2412 JIVE boot control - - See arch/arm/mach-s3c/mach-jive.c - mtouchusb.raw_coordinates= [HW] Make the MicroTouch USB driver use raw coordinates ('y', default) or cooked coordinates ('n') @@ -3857,9 +3830,6 @@ noalign [KNL,ARM] - noaltinstr [S390,EARLY] Disables alternative instructions - patching (CPU alternatives feature). - noapic [SMP,APIC,EARLY] Tells the kernel to not make use of any IOAPICs that may be present in the system. @@ -3891,8 +3861,6 @@ no_entry_flush [PPC,EARLY] Don't flush the L1-D cache when entering the kernel. - noexec [IA-64] - noexec32 [X86-64] This affects only 32-bit executables. noexec32=on: enable non-executable mappings (default) @@ -3912,13 +3880,6 @@ register save and restore. The kernel will only save legacy floating-point registers on task switch. - nohalt [IA-64] Tells the kernel not to use the power saving - function PAL_HALT_LIGHT when idle. This increases - power-consumption. On the positive side, it reduces - interrupt wake-up latency, which may improve performance - in certain environments such as networked servers or - real-time systems. - no_hash_pointers [KNL,EARLY] Force pointers printed to the console or buffers to be @@ -3936,7 +3897,7 @@ nohibernate [HIBERNATION] Disable hibernation and resume. - nohlt [ARM,ARM64,MICROBLAZE,MIPS,PPC,SH] Forces the kernel to + nohlt [ARM,ARM64,MICROBLAZE,MIPS,PPC,RISCV,SH] Forces the kernel to busy wait in do_idle() and not use the arch_cpu_idle() implementation; requires CONFIG_GENERIC_IDLE_POLL_SETUP to be effective. This is useful on platforms where the @@ -3973,8 +3934,6 @@ remapping. [Deprecated - use intremap=off] - nointroute [IA-64] - noinvpcid [X86,EARLY] Disable the INVPCID cpu feature. noiotrap [SH] Disables trapped I/O port accesses. @@ -3984,8 +3943,6 @@ noisapnp [ISAPNP] Disables ISA PnP code. - nojitter [IA-64] Disables jitter checking for ITC timers. - nokaslr [KNL,EARLY] When CONFIG_RANDOMIZE_BASE is set, this disables kernel and module base offset ASLR (Address Space @@ -4000,8 +3957,6 @@ nolapic_timer [X86-32,APIC,EARLY] Do not use the local APIC timer. - nomca [IA-64] Disable machine check abort handling - nomce [X86-32] Disable Machine Check Exception nomfgpt [X86-32] Disable Multi-Function General Purpose @@ -4053,8 +4008,6 @@ noresume [SWSUSP] Disables resume and restores original swap space. - nosbagart [IA-64] - no-scroll [VGA] Disables scrollback. This is required for the Braillex ib80-piezo Braille reader made by F.H. Papenmeier (Germany). @@ -4098,9 +4051,9 @@ prediction) vulnerability. System may allow data leaks with this option. - no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,EARLY] Disable - paravirtualized steal time accounting. steal time is - computed, but won't influence scheduler behaviour + no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,LOONGARCH,EARLY] + Disable paravirtualized steal time accounting. steal time + is computed, but won't influence scheduler behaviour nosync [HW,M68K] Disables sync negotiation for all devices. @@ -4155,19 +4108,6 @@ parameter, xsave area per process might occupy more memory on xsaves enabled systems. - nps_mtm_hs_ctr= [KNL,ARC] - This parameter sets the maximum duration, in - cycles, each HW thread of the CTOP can run - without interruptions, before HW switches it. - The actual maximum duration is 16 times this - parameter's value. - Format: integer between 1 and 255 - Default: 255 - - nptcg= [IA-64] Override max number of concurrent global TLB - purges which is reported from either PAL_VM_SUMMARY or - SAL PALO. - nr_cpus= [SMP,EARLY] Maximum number of processors that an SMP kernel could support. nr_cpus=n : n >= 1 limits the kernel to support 'n' processors. It could be larger than the @@ -4641,6 +4581,38 @@ bridges without forcing it upstream. Note: this removes isolation between devices and may put more devices in an IOMMU group. + config_acs= + Format: + <ACS flags>@<pci_dev>[; ...] + Specify one or more PCI devices (in the format + specified above) optionally prepended with flags + and separated by semicolons. The respective + capabilities will be enabled, disabled or + unchanged based on what is specified in + flags. + + ACS Flags is defined as follows: + bit-0 : ACS Source Validation + bit-1 : ACS Translation Blocking + bit-2 : ACS P2P Request Redirect + bit-3 : ACS P2P Completion Redirect + bit-4 : ACS Upstream Forwarding + bit-5 : ACS P2P Egress Control + bit-6 : ACS Direct Translated P2P + Each bit can be marked as: + '0' – force disabled + '1' – force enabled + 'x' – unchanged + For example, + pci=config_acs=10x + would configure all devices that support + ACS to enable P2P Request Redirect, disable + Translation Blocking, and leave Source + Validation unchanged from whatever power-up + or firmware set it to. + + Note: this may remove isolation between devices + and 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 @@ -4774,7 +4746,9 @@ 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 @@ -4824,11 +4798,9 @@ profile= [KNL] Enable kernel profiling via /proc/profile Format: [<profiletype>,]<number> - Param: <profiletype>: "schedule", "sleep", or "kvm" + Param: <profiletype>: "schedule" or "kvm" [defaults to kernel profiling] Param: "schedule" - profile schedule points. - Param: "sleep" - profile D-state sleeping (millisecs). - Requires CONFIG_SCHEDSTATS Param: "kvm" - profile VM exits. Param: <number> - step/bucket size as a power of 2 for statistical time based profiling. @@ -5040,6 +5012,14 @@ 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. @@ -5710,6 +5690,28 @@ them. If <base> is less than 0x10000, the region is assumed to be I/O ports; otherwise it is memory. + reserve_mem= [RAM] + Format: nn[KNG]:<align>:<label> + Reserve physical memory and label it with a name that + other subsystems can use to access it. This is typically + used for systems that do not wipe the RAM, and this command + line will try to reserve the same physical memory on + soft reboots. Note, it is not guaranteed to be the same + location. For example, if anything about the system changes + or if booting a different kernel. It can also fail if KASLR + places the kernel at the location of where the RAM reservation + was from a previous boot, the new reservation will be at a + different location. + Any subsystem using this feature must add a way to verify + that the contents of the physical memory is from a previous + boot, as there may be cases where the memory will not be + located at the same location. + + The format is size:align:label for example, to request + 12 megabytes of 4096 alignment for ramoops: + + reserve_mem=12M:4096:oops ramoops.mem_name=oops + reservetop= [X86-32,EARLY] Format: nn[KMG] Reserves a hole at the top of the kernel virtual @@ -5788,9 +5790,6 @@ 2 The "airplane mode" button toggles between everything blocked and everything unblocked. - rhash_entries= [KNL,NET] - Set number of hash buckets for route cache - ring3mwait=disable [KNL] Disable ring 3 MONITOR/MWAIT feature on supported CPUs. @@ -6024,9 +6023,6 @@ apic=verbose is specified. Example: apic=debug show_lapic=all - simeth= [IA-64] - simscsi= - slab_debug[=options[,slabs][;[options[,slabs]]...] [MM] Enabling slab_debug allows one to determine the culprit if slab objects become corrupted. Enabling @@ -6142,9 +6138,15 @@ 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. @@ -6288,11 +6290,6 @@ Not specifying this option is equivalent to spec_store_bypass_disable=auto. - spia_io_base= [HW,MTD] - spia_fio_base= - spia_pedr= - spia_peddr= - split_lock_detect= [X86] Enable split lock detection or bus lock detection @@ -6548,7 +6545,7 @@ This parameter controls use of the Protected Execution Facility on pSeries. - swiotlb= [ARM,IA-64,PPC,MIPS,X86,EARLY] + swiotlb= [ARM,PPC,MIPS,X86,S390,EARLY] Format: { <int> [,<int>] | force | noforce } <int> -- Number of I/O TLB slabs <int> -- Second integer after comma. Number of swiotlb @@ -6629,12 +6626,6 @@ e.g. base its process migration decisions on it. Default is on. - topology_updates= [KNL, PPC, NUMA] - Format: {off} - Specify if the kernel should ignore (off) - 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. @@ -6654,8 +6645,6 @@ torture.verbose_sleep_duration= [KNL] Duration of each verbose-printk() sleep in jiffies. - tp720= [HW,PS2] - tpm_suspend_pcr=[HW,TPM] Format: integer pcr id Specify that at suspend time, the tpm driver @@ -7108,6 +7097,9 @@ usb-storage.delay_use= [UMS] The delay in seconds before a new device is scanned for Logical Units (default 1). + Optionally the delay in milliseconds if the value has + suffix with "ms". + Example: delay_use=2567ms usb-storage.quirks= [UMS] A list of quirks entries to supplement or @@ -7201,9 +7193,6 @@ Try vdso32=0 if you encounter an error that says: dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! - vector= [IA-64,SMP] - vector=percpu: enable percpu vector domain - video= [FB,EARLY] Frame buffer configuration See Documentation/fb/modedb.rst. @@ -7254,9 +7243,12 @@ vmalloc=nn[KMG] [KNL,BOOT,EARLY] Forces the vmalloc area to have an exact size of <nn>. This can be used to increase - the minimum size (128MB on x86). It can also be - used to decrease the size and leave more room - for directly mapped kernel RAM. + the minimum size (128MB on x86, arm32 platforms). + It can also be used to decrease the size and leave more room + for directly mapped kernel RAM. Note that this parameter does + not exist on many other platforms (including arm64, alpha, + loongarch, arc, csky, hexagon, microblaze, mips, nios2, openrisc, + parisc, m64k, powerpc, riscv, sh, um, xtensa, s390, sparc). vmcp_cma=nn[MG] [KNL,S390,EARLY] Sets the memory size reserved for contiguous memory @@ -7461,17 +7453,18 @@ 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. |