mce=nobootlog
Disable boot machine check logging.
mce=tolerancelevel (number)
- 0: always panic, 1: panic if deadlock possible,
- 2: try to avoid panic, 3: never panic or exit (for testing)
- default is 1
+ 0: always panic on uncorrected errors, log corrected errors
+ 1: panic or SIGBUS on uncorrected errors, log corrected errors
+ 2: SIGBUS or log uncorrected errors, log corrected errors
+ 3: never panic or SIGBUS, log all errors (for testing only)
+ Default is 1
Can be also set using sysfs which is preferable.
nomce (for compatibility with i386): same as mce=off
Rebooting
- reboot=b[ios] | t[riple] | k[bd] [, [w]arm | [c]old]
- bios Use the CPU reboto vector for warm reset
+ reboot=b[ios] | t[riple] | k[bd] | a[cpi] | e[fi] [, [w]arm | [c]old]
+ 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)
kbd Use the keyboard controller. cold reset (default)
+ acpi Use the ACPI RESET_REG in the FADT. If ACPI is not configured or the
+ ACPI reset does not work, the reboot path attempts the reset using
+ the keyboard controller.
+ efi Use efi reset_system runtime service. If EFI is not configured or the
+ EFI reset does not work, the reboot path attempts the reset using
+ the keyboard controller.
Using warm reset will be much faster especially on big memory
systems because the BIOS will not go through the memory check.
SMP
- nosmp Only use a single CPU
-
- maxcpus=NUMBER only use upto NUMBER CPUs
-
- cpumask=MASK only use cpus with bits set in mask
-
additional_cpus=NUM Allow NUM more CPUs for hotplug
(defaults are specified by the BIOS, see Documentation/x86_64/cpu-hotplug-spec)
numa=noacpi Don't parse the SRAT table for NUMA setup
- numa=fake=X Fake X nodes and ignore NUMA setup of the actual machine.
+ numa=fake=CMDLINE
+ If a number, fakes CMDLINE nodes and ignores NUMA setup of the
+ actual machine. Otherwise, system memory is configured
+ depending on the sizes and coefficients listed. For example:
+ numa=fake=2*512,1024,4*256,*128
+ gives two 512M nodes, a 1024M node, four 256M nodes, and the
+ rest split into 128M chunks. If the last character of CMDLINE
+ is a *, the remaining memory is divided up equally among its
+ coefficient:
+ numa=fake=2*512,2*
+ gives two 512M nodes and the rest split into two nodes.
+ Otherwise, the remaining system RAM is allocated to an
+ additional node.
numa=hotadd=percent
Only allow hotadd memory to preallocate page structures upto
pci=lastbus=NUMBER Scan upto NUMBER busses, no matter what the mptable says.
pci=noacpi Don't use ACPI to set up PCI interrupt routing.
-IOMMU
-
- iommu=[size][,noagp][,off][,force][,noforce][,leak][,memaper[=order]][,merge]
- [,forcesac][,fullflush][,nomerge][,noaperture]
- size set size of iommu (in bytes)
- noagp don't initialize the AGP driver and use full aperture.
- off don't use the IOMMU
- leak turn on simple iommu leak tracing (only when CONFIG_IOMMU_LEAK is on)
- memaper[=order] allocate an own aperture over RAM with size 32MB^order.
- noforce don't force IOMMU usage. Default.
- force Force IOMMU.
- merge Do SG merging. Implies force (experimental)
- nomerge Don't do SG merging.
- forcesac For SAC mode for masks <40bits (experimental)
- fullflush Flush IOMMU on each allocation (default)
- nofullflush Don't use IOMMU fullflush
- 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
-
- 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>]
+IOMMU (input/output memory management unit)
+
+ Currently four x86-64 PCI-DMA mapping implementations exist:
+
+ 1. <arch/x86_64/kernel/pci-nommu.c>: use no hardware/software IOMMU at all
+ (e.g. because you have < 3 GB memory).
+ Kernel boot message: "PCI-DMA: Disabling IOMMU"
+
+ 2. <arch/x86_64/kernel/pci-gart.c>: AMD GART based hardware IOMMU.
+ Kernel boot message: "PCI-DMA: using GART IOMMU"
+
+ 3. <arch/x86_64/kernel/pci-swiotlb.c> : Software IOMMU implementation. Used
+ e.g. if there is no hardware IOMMU in the system and it is need because
+ you have >3GB memory or told the kernel to us it (iommu=soft))
+ Kernel boot message: "PCI-DMA: Using software bounce buffering
+ for IO (SWIOTLB)"
+
+ 4. <arch/x86_64/pci-calgary.c> : IBM Calgary hardware IOMMU. Used in IBM
+ pSeries and xSeries servers. This hardware IOMMU supports DMA address
+ mapping with memory protection, etc.
+ Kernel boot message: "PCI-DMA: Using Calgary IOMMU"
+
+ iommu=[<size>][,noagp][,off][,force][,noforce][,leak[=<nr_of_leak_pages>]
+ [,memaper[=<order>]][,merge][,forcesac][,fullflush][,nomerge]
+ [,noaperture][,calgary]
+
+ General iommu options:
+ off Don't initialize and use any kind of IOMMU.
+ noforce Don't force hardware IOMMU usage when it is not needed.
+ (default).
+ force Force the use of the hardware IOMMU even when it is
+ not actually needed (e.g. because < 3 GB memory).
+ soft Use software bounce buffering (SWIOTLB) (default for
+ Intel machines). This can be used to prevent the usage
+ of an available hardware IOMMU.
+
+ iommu options only relevant to the AMD GART hardware IOMMU:
+ <size> Set the size of the remapping area in bytes.
+ allowed Overwrite iommu off workarounds for specific chipsets.
+ fullflush Flush IOMMU on each allocation (default).
+ nofullflush Don't use IOMMU fullflush.
+ leak Turn on simple iommu leak tracing (only when
+ CONFIG_IOMMU_LEAK is on). Default number of leak pages
+ is 20.
+ memaper[=<order>] Allocate an own aperture over RAM with size 32MB<<order.
+ (default: order=1, i.e. 64MB)
+ merge Do scatter-gather (SG) merging. Implies "force"
+ (experimental).
+ nomerge Don't do scatter-gather (SG) merging.
+ noaperture Ask the IOMMU not to touch the aperture for AGP.
+ forcesac Force single-address cycle (SAC) mode for masks <40bits
+ (experimental).
+ noagp Don't initialize the AGP driver and use full aperture.
+ allowdac Allow double-address cycle (DAC) mode, i.e. DMA >4GB.
+ DAC is used with 32-bit PCI to push a 64-bit address in
+ two cycles. When off all DMA over >4GB is forced through
+ an IOMMU or software bounce buffering.
+ nodac Forbid DAC mode, i.e. DMA >4GB.
+ panic Always panic when IOMMU overflows.
+ calgary Use the Calgary IOMMU if it is available
+
+ iommu options only relevant to the software bounce buffering (SWIOTLB) IOMMU
+ implementation:
+ swiotlb=<pages>[,force]
+ <pages> Prereserve that many 128K pages for the software IO
+ bounce buffering.
+ force Force all IO through the software TLB.
+
+ Settings for the IBM Calgary hardware IOMMU currently found in IBM
+ pSeries and xSeries machines:
+
+ calgary=[64k,128k,256k,512k,1M,2M,4M,8M]
+ calgary=[translate_empty_slots]
+ calgary=[disable=<PCI bus number>]
+ panic Always panic when IOMMU overflows
64k,...,8M - Set the size of each PCI slot's translation table
when using the Calgary IOMMU. This is the size of the translation
Debugging
- oops=panic Always panic on oopses. Default is to just kill the process,
- but there is a small probability of deadlocking the machine.
- This will also cause panics on machine check exceptions.
- Useful together with panic=30 to trigger a reboot.
+ oops=panic Always panic on oopses. Default is to just kill the process,
+ but there is a small probability of deadlocking the machine.
+ This will also cause panics on machine check exceptions.
+ Useful together with panic=30 to trigger a reboot.
- kstack=N Print that many words from the kernel stack in oops dumps.
+ kstack=N Print N words from the kernel stack in oops dumps.
- pagefaulttrace Dump all page faults. Only useful for extreme debugging
+ pagefaulttrace Dump all page faults. Only useful for extreme debugging
and will create a lot of output.
call_trace=[old|both|newfallback|new]
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
+Miscellaneous
- noreplacement Don't replace instructions with more appropriate ones
- for the CPU. This may be useful on asymmetric MP systems
- where some CPU have less capabilities than the others.
+ nogbpages
+ Do not use GB pages for kernel direct mappings.
+ gbpages
+ Use GB pages for kernel direct mappings.
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff