+++ /dev/null
-AMD64 specific boot options
-
-There are many others (usually documented in driver documentation), but
-only the AMD64 specific ones are listed here.
-
-Machine check
-
- mce=off disable machine check
- mce=bootlog Enable logging of machine checks left over from booting.
- Disabled by default on AMD because some BIOS leave bogus ones.
- If your BIOS doesn't do that it's a good idea to enable though
- to make sure you log even machine check events that result
- in a reboot. On Intel systems it is enabled by default.
- mce=nobootlog
- Disable boot machine check logging.
- mce=tolerancelevel (number)
- 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
-
- Everything else is in sysfs now.
-
-APICs
-
- apic Use IO-APIC. Default
-
- noapic Don't use the IO-APIC.
-
- disableapic Don't use the local APIC
-
- nolapic Don't use the local APIC (alias for i386 compatibility)
-
- pirq=... See Documentation/i386/IO-APIC.txt
-
- noapictimer Don't set up the APIC timer
-
- no_timer_check Don't check the IO-APIC timer. This can work around
- problems with incorrect timer initialization on some boards.
-
- apicmaintimer Run time keeping from the local APIC timer instead
- of using the PIT/HPET interrupt for this. This is useful
- when the PIT/HPET interrupts are unreliable.
-
- noapicmaintimer Don't do time keeping using the APIC timer.
- Useful when this option was auto selected, but doesn't work.
-
- apicpmtimer
- Do APIC timer calibration using the pmtimer. Implies
- apicmaintimer. Useful when your PIT timer is totally
- broken.
-
- disable_8254_timer / enable_8254_timer
- Enable interrupt 0 timer routing over the 8254 in addition to over
- the IO-APIC. The kernel tries to set a sensible default.
-
-Early Console
-
- syntax: earlyprintk=vga
- earlyprintk=serial[,ttySn[,baudrate]]
-
- The early console is useful when the kernel crashes before the
- normal console is initialized. It is not enabled by
- default because it has some cosmetic problems.
- Append ,keep to not disable it when the real console takes over.
- Only vga or serial at a time, not both.
- Currently only ttyS0 and ttyS1 are supported.
- Interaction with the standard serial driver is not very good.
- The VGA output is eventually overwritten by the real console.
-
-Timing
-
- notsc
- Don't use the CPU time stamp counter to read the wall time.
- This can be used to work around timing problems on multiprocessor systems
- with not properly synchronized CPUs.
-
- report_lost_ticks
- Report when timer interrupts are lost because some code turned off
- interrupts for too long.
-
- nmi_watchdog=NUMBER[,panic]
- NUMBER can be:
- 0 don't use an NMI watchdog
- 1 use the IO-APIC timer for the NMI watchdog
- 2 use the local APIC for the NMI watchdog using a performance counter. Note
- This will use one performance counter and the local APIC's performance
- vector.
- When panic is specified panic when an NMI watchdog timeout occurs.
- This is useful when you use a panic=... timeout and need the box
- quickly up again.
-
- nohpet
- Don't use the HPET timer.
-
-Idle loop
-
- idle=poll
- Don't do power saving in the idle loop using HLT, but poll for rescheduling
- event. This will make the CPUs eat a lot more power, but may be useful
- to get slightly better performance in multiprocessor benchmarks. It also
- makes some profiling using performance counters more accurate.
- Please note that on systems with MONITOR/MWAIT support (like Intel EM64T
- CPUs) this option has no performance advantage over the normal idle loop.
- It may also interact badly with hyperthreading.
-
-Rebooting
-
- 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.
- Disadvantage is that not all hardware will be completely reinitialized
- on reboot so there may be boot problems on some systems.
-
- reboot=force
-
- Don't stop other CPUs on reboot. This can make reboot more reliable
- in some cases.
-
-Non Executable Mappings
-
- noexec=on|off
-
- on Enable(default)
- off Disable
-
-SMP
-
- additional_cpus=NUM Allow NUM more CPUs for hotplug
- (defaults are specified by the BIOS, see Documentation/x86_64/cpu-hotplug-spec)
-
-NUMA
-
- numa=off Only set up a single NUMA node spanning all memory.
-
- numa=noacpi Don't parse the SRAT table for NUMA setup
-
- 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
- percent of already available memory.
- numa=hotadd=0 will disable hotadd memory.
-
-ACPI
-
- acpi=off Don't enable ACPI
- acpi=ht Use ACPI boot table parsing, but don't enable ACPI
- interpreter
- acpi=force Force ACPI on (currently not needed)
-
- acpi=strict Disable out of spec ACPI workarounds.
-
- acpi_sci={edge,level,high,low} Set up ACPI SCI interrupt.
-
- acpi=noirq Don't route interrupts
-
-PCI
-
- pci=off Don't use PCI
- pci=conf1 Use conf1 access.
- pci=conf2 Use conf2 access.
- pci=rom Assign ROMs.
- pci=assign-busses Assign busses
- pci=irqmask=MASK Set PCI interrupt mask to MASK
- 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 (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
- 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,
- 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 N words from the kernel stack in oops dumps.
-
- 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)
-
-Miscellaneous
-
- nogbpages
- Do not use GB pages for kernel direct mappings.
- gbpages
- Use GB pages for kernel direct mappings.
git.openpandora.org / pandora-kernel.git / blobdiff