Rebooting
reboot=b[ios] | t[riple] | k[bd] [, [w]arm | [c]old]
- bios Use the CPU reboto vector for warm reset
+ bios Use the CPU reboot vector for warm reset
warm Don't set the cold reboot flag
cold Set the cold reboot flag
triple Force a triple fault (init)
numa=fake=X Fake X nodes and ignore NUMA setup of the actual machine.
+ numa=hotadd=percent
+ Only allow hotadd memory to preallocate page structures upto
+ percent of already available memory.
+ numa=hotadd=0 will disable hotadd memory.
+
ACPI
acpi=off Don't enable ACPI
IOMMU
iommu=[size][,noagp][,off][,force][,noforce][,leak][,memaper[=order]][,merge]
- [,forcesac][,fullflush][,nomerge][,noaperture]
+ [,forcesac][,fullflush][,nomerge][,noaperture][,calgary]
size set size of iommu (in bytes)
noagp don't initialize the AGP driver and use full aperture.
off don't use the IOMMU
allowed overwrite iommu off workarounds for specific chipsets.
soft Use software bounce buffering (default for Intel machines)
noaperture Don't touch the aperture for AGP.
+ allowdac Allow DMA >4GB
+ When off all DMA over >4GB is forced through an IOMMU or bounce
+ buffering.
+ nodac Forbid DMA >4GB
+ panic Always panic when IOMMU overflows
+ calgary Use the Calgary IOMMU if it is available
swiotlb=pages[,force]
pages Prereserve that many 128K pages for the software IO bounce buffering.
force Force all IO through the software TLB.
+ calgary=[64k,128k,256k,512k,1M,2M,4M,8M]
+ calgary=[translate_empty_slots]
+ calgary=[disable=<PCI bus number>]
+
+ 64k,...,8M - Set the size of each PCI slot's translation table
+ when using the Calgary IOMMU. This is the size of the translation
+ table itself in main memory. The smallest table, 64k, covers an IO
+ space of 32MB; the largest, 8MB table, can cover an IO space of
+ 4GB. Normally the kernel will make the right choice by itself.
+
+ translate_empty_slots - Enable translation even on slots that have
+ no devices attached to them, in case a device will be hotplugged
+ in the future.
+
+ disable=<PCI bus number> - Disable translation on a given PHB. For
+ example, the built-in graphics adapter resides on the first bridge
+ (PCI bus number 0); if translation (isolation) is enabled on this
+ bridge, X servers that access the hardware directly from user
+ space might stop working. Use this option if you have devices that
+ are accessed from userspace directly on some PCI host bridge.
+
Debugging
oops=panic Always panic on oopses. Default is to just kill the process,
pagefaulttrace Dump all page faults. Only useful for extreme debugging
and will create a lot of output.
+ call_trace=[old|both|newfallback|new]
+ old: use old inexact backtracer
+ new: use new exact dwarf2 unwinder
+ both: print entries from both
+ newfallback: use new unwinder but fall back to old if it gets
+ stuck (default)
+
+ call_trace=[old|both|newfallback|new]
+ old: use old inexact backtracer
+ new: use new exact dwarf2 unwinder
+ both: print entries from both
+ newfallback: use new unwinder but fall back to old if it gets
+ stuck (default)
+
Misc
noreplacement Don't replace instructions with more appropriate ones