Linux kernel boot parameters

Linux kernel boot parameters

Console Options

Parameters

Description

Options

Kernel Configuration/File

Console=options

Used to describe the output device

Ttyn Terminal ttysn[,options], ttyusb0[,options] serial uart,io,addr[,options],uart,mmio,addr[,options]&<60;

Netconsole=[src-port]@[src-ip]/[dev],[target-port] @target-ip/[targetmac-address]

Debug

Enable kernel debugging.

Output All debug information to the console at startup

Quiet

Disable all log messages.

Equivalent to Loglevel=kern_warning

Earlyprintk=[vga|serial][,ttysn[,baudrate]][,keep]

Print the information before the traditional console initialization, mainly hardware-related information

Loglevel=level

To set the default console logging level

All higher levels of information will be printed (0-7)

/proc/sys/kernel/printk

LOG_BUF_LEN=N[KMG]

Set the kernel record buffer size

For 2 of the underworld

Config_log_buf_shift

Initcall_debug

debugging system initialization functions

Keep track of all the functions that are used when the system starts

Kstack=n

How many words of the oops stack are output

N is an integer

Time

Show time before recording information

Interrupt Options (Advanced Programmable Interrupt Controller APIC)

Apic=[quiet|verbose|debug]

Changing the level of logging when the ACPI subsystem starts

Default is quite

Noapic

Without any ioapics.

Lapic

Make local ACPI valid

Even if Bois makes it ineffective, make it work.

Nolapic

Do not use ACPI

Noirqbalance

Invalid IRQ balance logic built into the kernel

Irqfixup

Basic Interrupt Issue Repair

When an interrupt is not processed, search for all interrupt processing to see if it can be used

Irqpoll

Extended Interrupt Issue Fix

At every clock interrupt, check each medium break processing

Noirqdebug

Disable automatic detection of unhandled interrupts

By default, the kernel tries to detect and suppress an unhandled interrupt source, preventing an unknown problem, which is prohibited by this option.

Memory Options

Highmem=n

Describe the size of a high memory area

Forces high-end memory to have an accurate memory area of size n, which can be used to reduce high-end memory size in large memory systems, regardless of whether the system has high-end memory

Hugepages=n

Set the number of hugetlb pages

Ihash_entries=n

To set the size of an inode hash table

Default value for overriding the kernel

Max_addr=n

Set the maximum memory address

The kernel will ignore the physical memory above the address

MEM=N[KMG]

Set the amount of memory used by memory

When you use the MEMMAP option, you can avoid conflicts in the physical address space. If you do not use the MEMMAP option, you may cause the PCI device to be placed in unused RAM space.

Mem=nopentium

Kernel Disable large page (4M)

Memmap=exactmap

Use a specific memory image

MEMMAP=N[KMG] @start [KMG]

Forcing the kernel to use a specific area of memory

N, which is the size of the table memory area, start refers to the starting bit position of the memory area

Noexec=[on|off]

Disable/enable the ability of the kernel to image a memory region as non-executable memory. The default is on.

RESERVE=N[KMG]

Forcing the kernel to ignore IO memory areas

Reserved IO memory Area

VMALLOC=N[KMG]

Forcing Vmalloc to have a specific size

Can be used to increase the minimum value of the Vmalloc area, or to reduce the size of the vmalloc, adding more space for direct mapping of kernel RAM

Norandmaps

No address space randomization

The default kernel randomization program-initiated address, which disables the feature

/proc/sys/kernel/randomize_va_space Write 0 quite

VDSO=[0|1]

Disable/enable VDSO image

(Virtual Dynamic Shared Object), which is enabled by default

Suspend Options

Resume=suspend_device

The partition device that describes the hibernation file

Noresume

Disabling the Hibernate feature

Ramdisk Options

Initrd=filename

Location of INITRD RAMDisk

Describes the location of the RAMDisk to be used when the kernel starts

Load_ramdisk=n

Loading RAMDisk from floppy disk

N=1, the RAMDisk is loaded from the floppy disk

Noinitrd

Without any initrd, even when the parameters are specified

Prompt_ramdisk=1

Prompt the user before reading RAMDisk from the floppy drive

Ramdisk_blocksize=n

Block size of RAMDisk

Ramdisk_size=n

Explains the size of the RAMDisk

Root Disk Options

Ro

Mount the root file system as read-only at startup

If there is an option for RW before it, RO will replace it

Root=device

Describes the system-initiated root file system

NNNN 16 (major and minor in a kernel-recognizable manner)/dev/nfs/dev/<diskname>/dev/<diskname><decimal>/dev/< Diskname>p<decimal> (requires DiskName to end with a number)

Rootdelay=n

Delay before mounting the file system

Primarily when the root file system is on a USB or FireWire device

Rootflags=options

Root file system mount options

Rootfstype=type

Types of root file systems

Example: ROOTFSTYPE=EXT3

rw

Mount the root filesystem in read-write mode at startup

Init Options

Init=filename

The program that should be executed at Init

Default is/sbin/init

Rdinit=full_path_name

Run Init from RAMDisk

The specified file must be in RAMDisk and not in the root file system

S

Run init in single-user mode

Network Options

Netdev=[irq],[io],[mem_start],[mem_end],[name]

Network parameters of the equipment

Thash_entries

Set the maximum number of TCP connection hash tables

Network File System Options

Lockd.nlm_grace_period=n

Appropriate lock management cycle for the device

In units of seconds

Lockd.nlm_tcpport=port

To set the port (TCP) for the NFS lock manager

Lockd.nlm_timeout=n

NFS Lock manager timed out

Default is 10 seconds

Lockd.nlm_udpport=port

To set the port (UDP) for the NFS lock manager

Nfsroot=[server-ip:]root-dir[,nfs-options]

For diskless Systems, note the NFS root file system if the parameter is not set by default to/tftpboot/client_ip_address

Nfs.callback_tcpport=port

Set nfsv4&<60; for the callback channel TCP port

Hardware-specific Options

Nousb

No USB device

lp=[0|port[,port...]| Reset|auto]

Set the parallel port and its mode

Lp=auto kernel will check all ports to see if there are ieee&<60;1284 compatible printers

Parport=[setting[,setting ...]

Description Parallel Port Parameters

Parport_init_mode=[spp|ps2|epp|ecp|ecpepp]

Parallel port Initialization mode

Nr_uarts=n

Maximum number of UART registrations

Panic=n

System panic after reboot maximum wait time

Default is 0, the system will not restart, just hang

Pause_on_oops=n

Tell the kernel that when the first oops appears, suspend all cpu,n seconds to record the live

Combined_mode=[combined|ide|libata]

Description IDE Driver

PCI Options

Pci=option[,option ...]

Offbiosnobiosbiosirqromnoacpirouteirqfirmware

Linux kernel boot parameters