9e43e1b7c7
CONFIG_CHECKING covered some debugging code used in the early times of the port. But it wasn't even SMP safe for quite some time and the bugs it checked for seem to be gone. This patch removes all the code to verify GS at kernel entry. There haven't been any new bugs in this area for a long time. Previously it also covered the sysctl for the page fault tracing. That didn't make much sense because that code was unconditionally compiled in. I made that a boot option now because it is typically only useful at boot. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
204 lines
6.6 KiB
Plaintext
204 lines
6.6 KiB
Plaintext
AMD64 specific boot options
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There are many others (usually documented in driver documentation), but
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only the AMD64 specific ones are listed here.
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Machine check
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mce=off disable machine check
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mce=bootlog Enable logging of machine checks left over from booting.
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Disabled by default on AMD because some BIOS leave bogus ones.
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If your BIOS doesn't do that it's a good idea to enable though
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to make sure you log even machine check events that result
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in a reboot. On Intel systems it is enabled by default.
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mce=nobootlog
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Disable boot machine check logging.
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mce=tolerancelevel (number)
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0: always panic, 1: panic if deadlock possible,
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2: try to avoid panic, 3: never panic or exit (for testing)
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default is 1
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Can be also set using sysfs which is preferable.
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nomce (for compatibility with i386): same as mce=off
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Everything else is in sysfs now.
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APICs
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apic Use IO-APIC. Default
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noapic Don't use the IO-APIC.
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disableapic Don't use the local APIC
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nolapic Don't use the local APIC (alias for i386 compatibility)
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pirq=... See Documentation/i386/IO-APIC.txt
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noapictimer Don't set up the APIC timer
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no_timer_check Don't check the IO-APIC timer. This can work around
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problems with incorrect timer initialization on some boards.
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Early Console
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syntax: earlyprintk=vga
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earlyprintk=serial[,ttySn[,baudrate]]
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The early console is useful when the kernel crashes before the
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normal console is initialized. It is not enabled by
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default because it has some cosmetic problems.
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Append ,keep to not disable it when the real console takes over.
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Only vga or serial at a time, not both.
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Currently only ttyS0 and ttyS1 are supported.
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Interaction with the standard serial driver is not very good.
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The VGA output is eventually overwritten by the real console.
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Timing
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notsc
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Don't use the CPU time stamp counter to read the wall time.
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This can be used to work around timing problems on multiprocessor systems
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with not properly synchronized CPUs.
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report_lost_ticks
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Report when timer interrupts are lost because some code turned off
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interrupts for too long.
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nmi_watchdog=NUMBER[,panic]
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NUMBER can be:
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0 don't use an NMI watchdog
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1 use the IO-APIC timer for the NMI watchdog
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2 use the local APIC for the NMI watchdog using a performance counter. Note
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This will use one performance counter and the local APIC's performance
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vector.
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When panic is specified panic when an NMI watchdog timeout occurs.
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This is useful when you use a panic=... timeout and need the box
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quickly up again.
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nohpet
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Don't use the HPET timer.
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Idle loop
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idle=poll
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Don't do power saving in the idle loop using HLT, but poll for rescheduling
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event. This will make the CPUs eat a lot more power, but may be useful
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to get slightly better performance in multiprocessor benchmarks. It also
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makes some profiling using performance counters more accurate.
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Please note that on systems with MONITOR/MWAIT support (like Intel EM64T
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CPUs) this option has no performance advantage over the normal idle loop.
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It may also interact badly with hyperthreading.
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Rebooting
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reboot=b[ios] | t[riple] | k[bd] [, [w]arm | [c]old]
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bios Use the CPU reboto vector for warm reset
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warm Don't set the cold reboot flag
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cold Set the cold reboot flag
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triple Force a triple fault (init)
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kbd Use the keyboard controller. cold reset (default)
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Using warm reset will be much faster especially on big memory
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systems because the BIOS will not go through the memory check.
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Disadvantage is that not all hardware will be completely reinitialized
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on reboot so there may be boot problems on some systems.
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reboot=force
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Don't stop other CPUs on reboot. This can make reboot more reliable
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in some cases.
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Non Executable Mappings
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noexec=on|off
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on Enable(default)
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off Disable
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SMP
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nosmp Only use a single CPU
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maxcpus=NUMBER only use upto NUMBER CPUs
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cpumask=MASK only use cpus with bits set in mask
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additional_cpus=NUM Allow NUM more CPUs for hotplug
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(defaults are specified by the BIOS or half the available CPUs)
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NUMA
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numa=off Only set up a single NUMA node spanning all memory.
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numa=noacpi Don't parse the SRAT table for NUMA setup
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numa=fake=X Fake X nodes and ignore NUMA setup of the actual machine.
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ACPI
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acpi=off Don't enable ACPI
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acpi=ht Use ACPI boot table parsing, but don't enable ACPI
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interpreter
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acpi=force Force ACPI on (currently not needed)
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acpi=strict Disable out of spec ACPI workarounds.
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acpi_sci={edge,level,high,low} Set up ACPI SCI interrupt.
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acpi=noirq Don't route interrupts
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PCI
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pci=off Don't use PCI
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pci=conf1 Use conf1 access.
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pci=conf2 Use conf2 access.
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pci=rom Assign ROMs.
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pci=assign-busses Assign busses
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pci=irqmask=MASK Set PCI interrupt mask to MASK
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pci=lastbus=NUMBER Scan upto NUMBER busses, no matter what the mptable says.
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pci=noacpi Don't use ACPI to set up PCI interrupt routing.
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IOMMU
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iommu=[size][,noagp][,off][,force][,noforce][,leak][,memaper[=order]][,merge]
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[,forcesac][,fullflush][,nomerge][,noaperture]
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size set size of iommu (in bytes)
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noagp don't initialize the AGP driver and use full aperture.
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off don't use the IOMMU
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leak turn on simple iommu leak tracing (only when CONFIG_IOMMU_LEAK is on)
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memaper[=order] allocate an own aperture over RAM with size 32MB^order.
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noforce don't force IOMMU usage. Default.
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force Force IOMMU.
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merge Do SG merging. Implies force (experimental)
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nomerge Don't do SG merging.
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forcesac For SAC mode for masks <40bits (experimental)
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fullflush Flush IOMMU on each allocation (default)
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nofullflush Don't use IOMMU fullflush
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allowed overwrite iommu off workarounds for specific chipsets.
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soft Use software bounce buffering (default for Intel machines)
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noaperture Don't touch the aperture for AGP.
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swiotlb=pages[,force]
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pages Prereserve that many 128K pages for the software IO bounce buffering.
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force Force all IO through the software TLB.
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Debugging
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oops=panic Always panic on oopses. Default is to just kill the process,
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but there is a small probability of deadlocking the machine.
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This will also cause panics on machine check exceptions.
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Useful together with panic=30 to trigger a reboot.
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kstack=N Print that many words from the kernel stack in oops dumps.
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pagefaulttrace Dump all page faults. Only useful for extreme debugging
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and will create a lot of output.
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Misc
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noreplacement Don't replace instructions with more appropiate ones
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for the CPU. This may be useful on asymmetric MP systems
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where some CPU have less capabilities than the others.
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