- Kernel Parameters
- ~~~~~~~~~~~~~~~~~
+ Kernel Parameters
+ ~~~~~~~~~~~~~~~~~
The following is a consolidated list of the kernel parameters as implemented
(mostly) by the __setup() macro and sorted into English Dictionary order
Format:
<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
- cpia_pp= [HW,PPT]
- Format: { parport<nr> | auto | none }
-
crashkernel=nn[KMG]@ss[KMG]
[KNL] Reserve a chunk of physical memory to
hold a kernel to switch to with kexec on panic.
Format: <1-256>
maxcpus= [SMP] Maximum number of processors that an SMP kernel
- should make use of.
- Using "nosmp" or "maxcpus=0" will disable SMP
- entirely (the MPS table probe still happens, though).
- A command-line option of "maxcpus=<NUM>", where <NUM>
- is an integer greater than 0, limits the maximum number
- of CPUs activated in SMP mode to <NUM>.
- Using "maxcpus=1" on an SMP kernel is the trivial
- case of an SMP kernel with only one CPU.
+ should make use of. maxcpus=n : n >= 0 limits the
+ kernel to using 'n' processors. n=0 is a special case,
+ it is equivalent to "nosmp", which also disables
+ the IO APIC.
max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
equal to this physical address is ignored.
nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
- nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
+ nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
+ and disable the IO APIC. legacy for "maxcpus=0".
nosoftlockup [KNL] Disable the soft-lockup detector.
reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Format: <reboot_mode>[,<reboot_mode2>[,...]]
- See arch/*/kernel/reboot.c or arch/*/kernel/process.c
+ See arch/*/kernel/reboot.c or arch/*/kernel/process.c
reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
selinux_compat_net =
[SELINUX] Set initial selinux_compat_net flag value.
- Format: { "0" | "1" }
- 0 -- use new secmark-based packet controls
- 1 -- use legacy packet controls
- Default value is 0 (preferred).
- Value can be changed at runtime via
- /selinux/compat_net.
+ Format: { "0" | "1" }
+ 0 -- use new secmark-based packet controls
+ 1 -- use legacy packet controls
+ Default value is 0 (preferred).
+ Value can be changed at runtime via
+ /selinux/compat_net.
serialnumber [BUGS=X86-32]
-1: disable all active trip points in all thermal zones
<degrees C>: override all lowest active trip points
+ thermal.crt= [HW,ACPI]
+ -1: disable all critical trip points in all thermal zones
+ <degrees C>: lower all critical trip points
+
thermal.nocrt= [HW,ACPI]
Set to disable actions on ACPI thermal zone
critical and hot trip points.
norandmaps Don't use address space randomization
Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
- unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
+ unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
This is useful to get more information why
you got a "dwarf2 unwinder stuck"