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linux/arch/x86/Kconfig
Ingo Molnar 04da8a43da perf_counter, x86: Fix/improve apic fallback 
Johannes Stezenbach reported that his Pentium-M based
laptop does not have the local APIC enabled by default,
and hence perfcounters do not get initialized.

Add a fallback for this case: allow non-sampled counters
and return with an error on sampled counters. This allows
'perf stat' to work out of box - and allows 'perf top'
and 'perf record' to fall back on a hrtimer based sampling
method.

( Passing 'lapic' on the boot line will allow hardware
  sampling to occur - but if the APIC is disabled
  permanently by the hardware then this fallback still
  allows more systems to use perfcounters. )

Also decouple perfcounter support from X86_LOCAL_APIC.

-v2: fix typo breaking counters on all other systems ...

Reported-by: Johannes Stezenbach <js@sig21.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-12 14:12:49 +02:00

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# x86 configuration
mainmenu "Linux Kernel Configuration for x86"
# Select 32 or 64 bit
config 64BIT
bool "64-bit kernel" if ARCH = "x86"
default ARCH = "x86_64"
---help---
Say yes to build a 64-bit kernel - formerly known as x86_64
Say no to build a 32-bit kernel - formerly known as i386
config X86_32
def_bool !64BIT
config X86_64
def_bool 64BIT
### Arch settings
config X86
def_bool y
select HAVE_AOUT if X86_32
select HAVE_READQ
select HAVE_WRITEQ
select HAVE_UNSTABLE_SCHED_CLOCK
select HAVE_IDE
select HAVE_OPROFILE
select HAVE_PERF_COUNTERS if (!M386 && !M486)
select HAVE_IOREMAP_PROT
select HAVE_KPROBES
select ARCH_WANT_OPTIONAL_GPIOLIB
select ARCH_WANT_FRAME_POINTERS
select HAVE_DMA_ATTRS
select HAVE_KRETPROBES
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_DYNAMIC_FTRACE
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_GRAPH_FP_TEST
select HAVE_FUNCTION_TRACE_MCOUNT_TEST
select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
select HAVE_FTRACE_SYSCALLS
select HAVE_KVM
select HAVE_ARCH_KGDB
select HAVE_ARCH_TRACEHOOK
select HAVE_GENERIC_DMA_COHERENT if X86_32
select HAVE_EFFICIENT_UNALIGNED_ACCESS
select USER_STACKTRACE_SUPPORT
select HAVE_DMA_API_DEBUG
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_LZMA
select HAVE_ARCH_KMEMCHECK
config OUTPUT_FORMAT
string
default "elf32-i386" if X86_32
default "elf64-x86-64" if X86_64
config ARCH_DEFCONFIG
string
default "arch/x86/configs/i386_defconfig" if X86_32
default "arch/x86/configs/x86_64_defconfig" if X86_64
config GENERIC_TIME
def_bool y
config GENERIC_CMOS_UPDATE
def_bool y
config CLOCKSOURCE_WATCHDOG
def_bool y
config GENERIC_CLOCKEVENTS
def_bool y
config GENERIC_CLOCKEVENTS_BROADCAST
def_bool y
depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
config LOCKDEP_SUPPORT
def_bool y
config STACKTRACE_SUPPORT
def_bool y
config HAVE_LATENCYTOP_SUPPORT
def_bool y
config FAST_CMPXCHG_LOCAL
bool
default y
config MMU
def_bool y
config ZONE_DMA
def_bool y
config SBUS
bool
config GENERIC_ISA_DMA
def_bool y
config GENERIC_IOMAP
def_bool y
config GENERIC_BUG
def_bool y
depends on BUG
select GENERIC_BUG_RELATIVE_POINTERS if X86_64
config GENERIC_BUG_RELATIVE_POINTERS
bool
config GENERIC_HWEIGHT
def_bool y
config GENERIC_GPIO
bool
config ARCH_MAY_HAVE_PC_FDC
def_bool y
config RWSEM_GENERIC_SPINLOCK
def_bool !X86_XADD
config RWSEM_XCHGADD_ALGORITHM
def_bool X86_XADD
config ARCH_HAS_CPU_IDLE_WAIT
def_bool y
config GENERIC_CALIBRATE_DELAY
def_bool y
config GENERIC_TIME_VSYSCALL
bool
default X86_64
config ARCH_HAS_CPU_RELAX
def_bool y
config ARCH_HAS_DEFAULT_IDLE
def_bool y
config ARCH_HAS_CACHE_LINE_SIZE
def_bool y
config HAVE_SETUP_PER_CPU_AREA
def_bool y
config HAVE_DYNAMIC_PER_CPU_AREA
def_bool y
config HAVE_CPUMASK_OF_CPU_MAP
def_bool X86_64_SMP
config ARCH_HIBERNATION_POSSIBLE
def_bool y
config ARCH_SUSPEND_POSSIBLE
def_bool y
config ZONE_DMA32
bool
default X86_64
config ARCH_POPULATES_NODE_MAP
def_bool y
config AUDIT_ARCH
bool
default X86_64
config ARCH_SUPPORTS_OPTIMIZED_INLINING
def_bool y
config ARCH_SUPPORTS_DEBUG_PAGEALLOC
def_bool y
# Use the generic interrupt handling code in kernel/irq/:
config GENERIC_HARDIRQS
bool
default y
config GENERIC_HARDIRQS_NO__DO_IRQ
def_bool y
config GENERIC_IRQ_PROBE
bool
default y
config GENERIC_PENDING_IRQ
bool
depends on GENERIC_HARDIRQS && SMP
default y
config USE_GENERIC_SMP_HELPERS
def_bool y
depends on SMP
config X86_32_SMP
def_bool y
depends on X86_32 && SMP
config X86_64_SMP
def_bool y
depends on X86_64 && SMP
config X86_HT
bool
depends on SMP
default y
config X86_TRAMPOLINE
bool
depends on SMP || (64BIT && ACPI_SLEEP)
default y
config X86_32_LAZY_GS
def_bool y
depends on X86_32 && !CC_STACKPROTECTOR
config KTIME_SCALAR
def_bool X86_32
source "init/Kconfig"
source "kernel/Kconfig.freezer"
menu "Processor type and features"
source "kernel/time/Kconfig"
config SMP
bool "Symmetric multi-processing support"
---help---
This enables support for systems with more than one CPU. If you have
a system with only one CPU, like most personal computers, say N. If
you have a system with more than one CPU, say Y.
If you say N here, the kernel will run on single and multiprocessor
machines, but will use only one CPU of a multiprocessor machine. If
you say Y here, the kernel will run on many, but not all,
singleprocessor machines. On a singleprocessor machine, the kernel
will run faster if you say N here.
Note that if you say Y here and choose architecture "586" or
"Pentium" under "Processor family", the kernel will not work on 486
architectures. Similarly, multiprocessor kernels for the "PPro"
architecture may not work on all Pentium based boards.
People using multiprocessor machines who say Y here should also say
Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
Management" code will be disabled if you say Y here.
See also <file:Documentation/i386/IO-APIC.txt>,
<file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
<http://www.tldp.org/docs.html#howto>.
If you don't know what to do here, say N.
config X86_X2APIC
bool "Support x2apic"
depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
---help---
This enables x2apic support on CPUs that have this feature.
This allows 32-bit apic IDs (so it can support very large systems),
and accesses the local apic via MSRs not via mmio.
If you don't know what to do here, say N.
config SPARSE_IRQ
bool "Support sparse irq numbering"
depends on PCI_MSI || HT_IRQ
---help---
This enables support for sparse irqs. This is useful for distro
kernels that want to define a high CONFIG_NR_CPUS value but still
want to have low kernel memory footprint on smaller machines.
( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
out the irq_desc[] array in a more NUMA-friendly way. )
If you don't know what to do here, say N.
config NUMA_IRQ_DESC
def_bool y
depends on SPARSE_IRQ && NUMA
config X86_MPPARSE
bool "Enable MPS table" if ACPI
default y
depends on X86_LOCAL_APIC
---help---
For old smp systems that do not have proper acpi support. Newer systems
(esp with 64bit cpus) with acpi support, MADT and DSDT will override it
config X86_BIGSMP
bool "Support for big SMP systems with more than 8 CPUs"
depends on X86_32 && SMP
---help---
This option is needed for the systems that have more than 8 CPUs
if X86_32
config X86_EXTENDED_PLATFORM
bool "Support for extended (non-PC) x86 platforms"
default y
---help---
If you disable this option then the kernel will only support
standard PC platforms. (which covers the vast majority of
systems out there.)
If you enable this option then you'll be able to select support
for the following (non-PC) 32 bit x86 platforms:
AMD Elan
NUMAQ (IBM/Sequent)
RDC R-321x SoC
SGI 320/540 (Visual Workstation)
Summit/EXA (IBM x440)
Unisys ES7000 IA32 series
If you have one of these systems, or if you want to build a
generic distribution kernel, say Y here - otherwise say N.
endif
if X86_64
config X86_EXTENDED_PLATFORM
bool "Support for extended (non-PC) x86 platforms"
default y
---help---
If you disable this option then the kernel will only support
standard PC platforms. (which covers the vast majority of
systems out there.)
If you enable this option then you'll be able to select support
for the following (non-PC) 64 bit x86 platforms:
ScaleMP vSMP
SGI Ultraviolet
If you have one of these systems, or if you want to build a
generic distribution kernel, say Y here - otherwise say N.
endif
# This is an alphabetically sorted list of 64 bit extended platforms
# Please maintain the alphabetic order if and when there are additions
config X86_VSMP
bool "ScaleMP vSMP"
select PARAVIRT
depends on X86_64 && PCI
depends on X86_EXTENDED_PLATFORM
---help---
Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
supposed to run on these EM64T-based machines. Only choose this option
if you have one of these machines.
config X86_UV
bool "SGI Ultraviolet"
depends on X86_64
depends on X86_EXTENDED_PLATFORM
depends on NUMA
depends on X86_X2APIC
---help---
This option is needed in order to support SGI Ultraviolet systems.
If you don't have one of these, you should say N here.
# Following is an alphabetically sorted list of 32 bit extended platforms
# Please maintain the alphabetic order if and when there are additions
config X86_ELAN
bool "AMD Elan"
depends on X86_32
depends on X86_EXTENDED_PLATFORM
---help---
Select this for an AMD Elan processor.
Do not use this option for K6/Athlon/Opteron processors!
If unsure, choose "PC-compatible" instead.
config X86_RDC321X
bool "RDC R-321x SoC"
depends on X86_32
depends on X86_EXTENDED_PLATFORM
select M486
select X86_REBOOTFIXUPS
---help---
This option is needed for RDC R-321x system-on-chip, also known
as R-8610-(G).
If you don't have one of these chips, you should say N here.
config X86_32_NON_STANDARD
bool "Support non-standard 32-bit SMP architectures"
depends on X86_32 && SMP
depends on X86_EXTENDED_PLATFORM
---help---
This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
subarchitectures. It is intended for a generic binary kernel.
if you select them all, kernel will probe it one by one. and will
fallback to default.
# Alphabetically sorted list of Non standard 32 bit platforms
config X86_NUMAQ
bool "NUMAQ (IBM/Sequent)"
depends on X86_32_NON_STANDARD
select NUMA
select X86_MPPARSE
---help---
This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
NUMA multiquad box. This changes the way that processors are
bootstrapped, and uses Clustered Logical APIC addressing mode instead
of Flat Logical. You will need a new lynxer.elf file to flash your
firmware with - send email to <Martin.Bligh@us.ibm.com>.
config X86_VISWS
bool "SGI 320/540 (Visual Workstation)"
depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
depends on X86_32_NON_STANDARD
---help---
The SGI Visual Workstation series is an IA32-based workstation
based on SGI systems chips with some legacy PC hardware attached.
Say Y here to create a kernel to run on the SGI 320 or 540.
A kernel compiled for the Visual Workstation will run on general
PCs as well. See <file:Documentation/sgi-visws.txt> for details.
config X86_SUMMIT
bool "Summit/EXA (IBM x440)"
depends on X86_32_NON_STANDARD
---help---
This option is needed for IBM systems that use the Summit/EXA chipset.
In particular, it is needed for the x440.
config X86_ES7000
bool "Unisys ES7000 IA32 series"
depends on X86_32_NON_STANDARD && X86_BIGSMP
---help---
Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
supposed to run on an IA32-based Unisys ES7000 system.
config SCHED_OMIT_FRAME_POINTER
def_bool y
prompt "Single-depth WCHAN output"
depends on X86
---help---
Calculate simpler /proc/<PID>/wchan values. If this option
is disabled then wchan values will recurse back to the
caller function. This provides more accurate wchan values,
at the expense of slightly more scheduling overhead.
If in doubt, say "Y".
menuconfig PARAVIRT_GUEST
bool "Paravirtualized guest support"
---help---
Say Y here to get to see options related to running Linux under
various hypervisors. This option alone does not add any kernel code.
If you say N, all options in this submenu will be skipped and disabled.
if PARAVIRT_GUEST
source "arch/x86/xen/Kconfig"
config VMI
bool "VMI Guest support"
select PARAVIRT
depends on X86_32
---help---
VMI provides a paravirtualized interface to the VMware ESX server
(it could be used by other hypervisors in theory too, but is not
at the moment), by linking the kernel to a GPL-ed ROM module
provided by the hypervisor.
config KVM_CLOCK
bool "KVM paravirtualized clock"
select PARAVIRT
select PARAVIRT_CLOCK
---help---
Turning on this option will allow you to run a paravirtualized clock
when running over the KVM hypervisor. Instead of relying on a PIT
(or probably other) emulation by the underlying device model, the host
provides the guest with timing infrastructure such as time of day, and
system time
config KVM_GUEST
bool "KVM Guest support"
select PARAVIRT
---help---
This option enables various optimizations for running under the KVM
hypervisor.
source "arch/x86/lguest/Kconfig"
config PARAVIRT
bool "Enable paravirtualization code"
---help---
This changes the kernel so it can modify itself when it is run
under a hypervisor, potentially improving performance significantly
over full virtualization. However, when run without a hypervisor
the kernel is theoretically slower and slightly larger.
config PARAVIRT_SPINLOCKS
bool "Paravirtualization layer for spinlocks"
depends on PARAVIRT && SMP && EXPERIMENTAL
---help---
Paravirtualized spinlocks allow a pvops backend to replace the
spinlock implementation with something virtualization-friendly
(for example, block the virtual CPU rather than spinning).
Unfortunately the downside is an up to 5% performance hit on
native kernels, with various workloads.
If you are unsure how to answer this question, answer N.
config PARAVIRT_CLOCK
bool
default n
endif
config PARAVIRT_DEBUG
bool "paravirt-ops debugging"
depends on PARAVIRT && DEBUG_KERNEL
---help---
Enable to debug paravirt_ops internals. Specifically, BUG if
a paravirt_op is missing when it is called.
config MEMTEST
bool "Memtest"
---help---
This option adds a kernel parameter 'memtest', which allows memtest
to be set.
memtest=0, mean disabled; -- default
memtest=1, mean do 1 test pattern;
...
memtest=4, mean do 4 test patterns.
If you are unsure how to answer this question, answer N.
config X86_SUMMIT_NUMA
def_bool y
depends on X86_32 && NUMA && X86_32_NON_STANDARD
config X86_CYCLONE_TIMER
def_bool y
depends on X86_32_NON_STANDARD
source "arch/x86/Kconfig.cpu"
config HPET_TIMER
def_bool X86_64
prompt "HPET Timer Support" if X86_32
---help---
Use the IA-PC HPET (High Precision Event Timer) to manage
time in preference to the PIT and RTC, if a HPET is
present.
HPET is the next generation timer replacing legacy 8254s.
The HPET provides a stable time base on SMP
systems, unlike the TSC, but it is more expensive to access,
as it is off-chip. You can find the HPET spec at
<http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
You can safely choose Y here. However, HPET will only be
activated if the platform and the BIOS support this feature.
Otherwise the 8254 will be used for timing services.
Choose N to continue using the legacy 8254 timer.
config HPET_EMULATE_RTC
def_bool y
depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
# Mark as embedded because too many people got it wrong.
# The code disables itself when not needed.
config DMI
default y
bool "Enable DMI scanning" if EMBEDDED
---help---
Enabled scanning of DMI to identify machine quirks. Say Y
here unless you have verified that your setup is not
affected by entries in the DMI blacklist. Required by PNP
BIOS code.
config GART_IOMMU
bool "GART IOMMU support" if EMBEDDED
default y
select SWIOTLB
select AGP
depends on X86_64 && PCI
---help---
Support for full DMA access of devices with 32bit memory access only
on systems with more than 3GB. This is usually needed for USB,
sound, many IDE/SATA chipsets and some other devices.
Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
based hardware IOMMU and a software bounce buffer based IOMMU used
on Intel systems and as fallback.
The code is only active when needed (enough memory and limited
device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
too.
config CALGARY_IOMMU
bool "IBM Calgary IOMMU support"
select SWIOTLB
depends on X86_64 && PCI && EXPERIMENTAL
---help---
Support for hardware IOMMUs in IBM's xSeries x366 and x460
systems. Needed to run systems with more than 3GB of memory
properly with 32-bit PCI devices that do not support DAC
(Double Address Cycle). Calgary also supports bus level
isolation, where all DMAs pass through the IOMMU. This
prevents them from going anywhere except their intended
destination. This catches hard-to-find kernel bugs and
mis-behaving drivers and devices that do not use the DMA-API
properly to set up their DMA buffers. The IOMMU can be
turned off at boot time with the iommu=off parameter.
Normally the kernel will make the right choice by itself.
If unsure, say Y.
config CALGARY_IOMMU_ENABLED_BY_DEFAULT
def_bool y
prompt "Should Calgary be enabled by default?"
depends on CALGARY_IOMMU
---help---
Should Calgary be enabled by default? if you choose 'y', Calgary
will be used (if it exists). If you choose 'n', Calgary will not be
used even if it exists. If you choose 'n' and would like to use
Calgary anyway, pass 'iommu=calgary' on the kernel command line.
If unsure, say Y.
config AMD_IOMMU
bool "AMD IOMMU support"
select SWIOTLB
select PCI_MSI
depends on X86_64 && PCI && ACPI
---help---
With this option you can enable support for AMD IOMMU hardware in
your system. An IOMMU is a hardware component which provides
remapping of DMA memory accesses from devices. With an AMD IOMMU you
can isolate the the DMA memory of different devices and protect the
system from misbehaving device drivers or hardware.
You can find out if your system has an AMD IOMMU if you look into
your BIOS for an option to enable it or if you have an IVRS ACPI
table.
config AMD_IOMMU_STATS
bool "Export AMD IOMMU statistics to debugfs"
depends on AMD_IOMMU
select DEBUG_FS
---help---
This option enables code in the AMD IOMMU driver to collect various
statistics about whats happening in the driver and exports that
information to userspace via debugfs.
If unsure, say N.
# need this always selected by IOMMU for the VIA workaround
config SWIOTLB
def_bool y if X86_64
---help---
Support for software bounce buffers used on x86-64 systems
which don't have a hardware IOMMU (e.g. the current generation
of Intel's x86-64 CPUs). Using this PCI devices which can only
access 32-bits of memory can be used on systems with more than
3 GB of memory. If unsure, say Y.
config IOMMU_HELPER
def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
config IOMMU_API
def_bool (AMD_IOMMU || DMAR)
config MAXSMP
bool "Configure Maximum number of SMP Processors and NUMA Nodes"
depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
select CPUMASK_OFFSTACK
default n
---help---
Configure maximum number of CPUS and NUMA Nodes for this architecture.
If unsure, say N.
config NR_CPUS
int "Maximum number of CPUs" if SMP && !MAXSMP
range 2 8 if SMP && X86_32 && !X86_BIGSMP
range 2 512 if SMP && !MAXSMP
default "1" if !SMP
default "4096" if MAXSMP
default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
default "8" if SMP
---help---
This allows you to specify the maximum number of CPUs which this
kernel will support. The maximum supported value is 512 and the
minimum value which makes sense is 2.
This is purely to save memory - each supported CPU adds
approximately eight kilobytes to the kernel image.
config SCHED_SMT
bool "SMT (Hyperthreading) scheduler support"
depends on X86_HT
---help---
SMT scheduler support improves the CPU scheduler's decision making
when dealing with Intel Pentium 4 chips with HyperThreading at a
cost of slightly increased overhead in some places. If unsure say
N here.
config SCHED_MC
def_bool y
prompt "Multi-core scheduler support"
depends on X86_HT
---help---
Multi-core scheduler support improves the CPU scheduler's decision
making when dealing with multi-core CPU chips at a cost of slightly
increased overhead in some places. If unsure say N here.
source "kernel/Kconfig.preempt"
config X86_UP_APIC
bool "Local APIC support on uniprocessors"
depends on X86_32 && !SMP && !X86_32_NON_STANDARD
---help---
A local APIC (Advanced Programmable Interrupt Controller) is an
integrated interrupt controller in the CPU. If you have a single-CPU
system which has a processor with a local APIC, you can say Y here to
enable and use it. If you say Y here even though your machine doesn't
have a local APIC, then the kernel will still run with no slowdown at
all. The local APIC supports CPU-generated self-interrupts (timer,
performance counters), and the NMI watchdog which detects hard
lockups.
config X86_UP_IOAPIC
bool "IO-APIC support on uniprocessors"
depends on X86_UP_APIC
---help---
An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
SMP-capable replacement for PC-style interrupt controllers. Most
SMP systems and many recent uniprocessor systems have one.
If you have a single-CPU system with an IO-APIC, you can say Y here
to use it. If you say Y here even though your machine doesn't have
an IO-APIC, then the kernel will still run with no slowdown at all.
config X86_LOCAL_APIC
def_bool y
depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
config X86_IO_APIC
def_bool y
depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
config X86_VISWS_APIC
def_bool y
depends on X86_32 && X86_VISWS
config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
bool "Reroute for broken boot IRQs"
default n
depends on X86_IO_APIC
---help---
This option enables a workaround that fixes a source of
spurious interrupts. This is recommended when threaded
interrupt handling is used on systems where the generation of
superfluous "boot interrupts" cannot be disabled.
Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
entry in the chipset's IO-APIC is masked (as, e.g. the RT
kernel does during interrupt handling). On chipsets where this
boot IRQ generation cannot be disabled, this workaround keeps
the original IRQ line masked so that only the equivalent "boot
IRQ" is delivered to the CPUs. The workaround also tells the
kernel to set up the IRQ handler on the boot IRQ line. In this
way only one interrupt is delivered to the kernel. Otherwise
the spurious second interrupt may cause the kernel to bring
down (vital) interrupt lines.
Only affects "broken" chipsets. Interrupt sharing may be
increased on these systems.
config X86_MCE
bool "Machine Check Exception"
---help---
Machine Check Exception support allows the processor to notify the
kernel if it detects a problem (e.g. overheating, component failure).
The action the kernel takes depends on the severity of the problem,
ranging from a warning message on the console, to halting the machine.
Your processor must be a Pentium or newer to support this - check the
flags in /proc/cpuinfo for mce. Note that some older Pentium systems
have a design flaw which leads to false MCE events - hence MCE is
disabled on all P5 processors, unless explicitly enabled with "mce"
as a boot argument. Similarly, if MCE is built in and creates a
problem on some new non-standard machine, you can boot with "nomce"
to disable it. MCE support simply ignores non-MCE processors like
the 386 and 486, so nearly everyone can say Y here.
config X86_OLD_MCE
depends on X86_32 && X86_MCE
bool "Use legacy machine check code (will go away)"
default n
select X86_ANCIENT_MCE
---help---
Use the old i386 machine check code. This is merely intended for
testing in a transition period. Try this if you run into any machine
check related software problems, but report the problem to
linux-kernel. When in doubt say no.
config X86_NEW_MCE
depends on X86_MCE
bool
default y if (!X86_OLD_MCE && X86_32) || X86_64
config X86_MCE_INTEL
def_bool y
prompt "Intel MCE features"
depends on X86_NEW_MCE && X86_LOCAL_APIC
---help---
Additional support for intel specific MCE features such as
the thermal monitor.
config X86_MCE_AMD
def_bool y
prompt "AMD MCE features"
depends on X86_NEW_MCE && X86_LOCAL_APIC
---help---
Additional support for AMD specific MCE features such as
the DRAM Error Threshold.
config X86_ANCIENT_MCE
def_bool n
depends on X86_32
prompt "Support for old Pentium 5 / WinChip machine checks"
---help---
Include support for machine check handling on old Pentium 5 or WinChip
systems. These typically need to be enabled explicitely on the command
line.
config X86_MCE_THRESHOLD
depends on X86_MCE_AMD || X86_MCE_INTEL
bool
default y
config X86_MCE_INJECT
depends on X86_NEW_MCE
tristate "Machine check injector support"
---help---
Provide support for injecting machine checks for testing purposes.
If you don't know what a machine check is and you don't do kernel
QA it is safe to say n.
config X86_MCE_NONFATAL
tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
depends on X86_OLD_MCE
---help---
Enabling this feature starts a timer that triggers every 5 seconds which
will look at the machine check registers to see if anything happened.
Non-fatal problems automatically get corrected (but still logged).
Disable this if you don't want to see these messages.
Seeing the messages this option prints out may be indicative of dying
or out-of-spec (ie, overclocked) hardware.
This option only does something on certain CPUs.
(AMD Athlon/Duron and Intel Pentium 4)
config X86_MCE_P4THERMAL
bool "check for P4 thermal throttling interrupt."
depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
---help---
Enabling this feature will cause a message to be printed when the P4
enters thermal throttling.
config X86_THERMAL_VECTOR
def_bool y
depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
config VM86
bool "Enable VM86 support" if EMBEDDED
default y
depends on X86_32
---help---
This option is required by programs like DOSEMU to run 16-bit legacy
code on X86 processors. It also may be needed by software like
XFree86 to initialize some video cards via BIOS. Disabling this
option saves about 6k.
config TOSHIBA
tristate "Toshiba Laptop support"
depends on X86_32
---help---
This adds a driver to safely access the System Management Mode of
the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
not work on models with a Phoenix BIOS. The System Management Mode
is used to set the BIOS and power saving options on Toshiba portables.
For information on utilities to make use of this driver see the
Toshiba Linux utilities web site at:
<http://www.buzzard.org.uk/toshiba/>.
Say Y if you intend to run this kernel on a Toshiba portable.
Say N otherwise.
config I8K
tristate "Dell laptop support"
---help---
This adds a driver to safely access the System Management Mode
of the CPU on the Dell Inspiron 8000. The System Management Mode
is used to read cpu temperature and cooling fan status and to
control the fans on the I8K portables.
This driver has been tested only on the Inspiron 8000 but it may
also work with other Dell laptops. You can force loading on other
models by passing the parameter `force=1' to the module. Use at
your own risk.
For information on utilities to make use of this driver see the
I8K Linux utilities web site at:
<http://people.debian.org/~dz/i8k/>
Say Y if you intend to run this kernel on a Dell Inspiron 8000.
Say N otherwise.
config X86_REBOOTFIXUPS
bool "Enable X86 board specific fixups for reboot"
depends on X86_32
---help---
This enables chipset and/or board specific fixups to be done
in order to get reboot to work correctly. This is only needed on
some combinations of hardware and BIOS. The symptom, for which
this config is intended, is when reboot ends with a stalled/hung
system.
Currently, the only fixup is for the Geode machines using
CS5530A and CS5536 chipsets and the RDC R-321x SoC.
Say Y if you want to enable the fixup. Currently, it's safe to
enable this option even if you don't need it.
Say N otherwise.
config MICROCODE
tristate "/dev/cpu/microcode - microcode support"
select FW_LOADER
---help---
If you say Y here, you will be able to update the microcode on
certain Intel and AMD processors. The Intel support is for the
IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
Pentium 4, Xeon etc. The AMD support is for family 0x10 and
0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
You will obviously need the actual microcode binary data itself
which is not shipped with the Linux kernel.
This option selects the general module only, you need to select
at least one vendor specific module as well.
To compile this driver as a module, choose M here: the
module will be called microcode.
config MICROCODE_INTEL
bool "Intel microcode patch loading support"
depends on MICROCODE
default MICROCODE
select FW_LOADER
---help---
This options enables microcode patch loading support for Intel
processors.
For latest news and information on obtaining all the required
Intel ingredients for this driver, check:
<http://www.urbanmyth.org/microcode/>.
config MICROCODE_AMD
bool "AMD microcode patch loading support"
depends on MICROCODE
select FW_LOADER
---help---
If you select this option, microcode patch loading support for AMD
processors will be enabled.
config MICROCODE_OLD_INTERFACE
def_bool y
depends on MICROCODE
config X86_MSR
tristate "/dev/cpu/*/msr - Model-specific register support"
---help---
This device gives privileged processes access to the x86
Model-Specific Registers (MSRs). It is a character device with
major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
MSR accesses are directed to a specific CPU on multi-processor
systems.
config X86_CPUID
tristate "/dev/cpu/*/cpuid - CPU information support"
---help---
This device gives processes access to the x86 CPUID instruction to
be executed on a specific processor. It is a character device
with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
/dev/cpu/31/cpuid.
config X86_CPU_DEBUG
tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
---help---
If you select this option, this will provide various x86 CPUs
information through debugfs.
choice
prompt "High Memory Support"
default HIGHMEM4G if !X86_NUMAQ
default HIGHMEM64G if X86_NUMAQ
depends on X86_32
config NOHIGHMEM
bool "off"
depends on !X86_NUMAQ
---help---
Linux can use up to 64 Gigabytes of physical memory on x86 systems.
However, the address space of 32-bit x86 processors is only 4
Gigabytes large. That means that, if you have a large amount of
physical memory, not all of it can be "permanently mapped" by the
kernel. The physical memory that's not permanently mapped is called
"high memory".
If you are compiling a kernel which will never run on a machine with
more than 1 Gigabyte total physical RAM, answer "off" here (default
choice and suitable for most users). This will result in a "3GB/1GB"
split: 3GB are mapped so that each process sees a 3GB virtual memory
space and the remaining part of the 4GB virtual memory space is used
by the kernel to permanently map as much physical memory as
possible.
If the machine has between 1 and 4 Gigabytes physical RAM, then
answer "4GB" here.
If more than 4 Gigabytes is used then answer "64GB" here. This
selection turns Intel PAE (Physical Address Extension) mode on.
PAE implements 3-level paging on IA32 processors. PAE is fully
supported by Linux, PAE mode is implemented on all recent Intel
processors (Pentium Pro and better). NOTE: If you say "64GB" here,
then the kernel will not boot on CPUs that don't support PAE!
The actual amount of total physical memory will either be
auto detected or can be forced by using a kernel command line option
such as "mem=256M". (Try "man bootparam" or see the documentation of
your boot loader (lilo or loadlin) about how to pass options to the
kernel at boot time.)
If unsure, say "off".
config HIGHMEM4G
bool "4GB"
depends on !X86_NUMAQ
---help---
Select this if you have a 32-bit processor and between 1 and 4
gigabytes of physical RAM.
config HIGHMEM64G
bool "64GB"
depends on !M386 && !M486
select X86_PAE
---help---
Select this if you have a 32-bit processor and more than 4
gigabytes of physical RAM.
endchoice
choice
depends on EXPERIMENTAL
prompt "Memory split" if EMBEDDED
default VMSPLIT_3G
depends on X86_32
---help---
Select the desired split between kernel and user memory.
If the address range available to the kernel is less than the
physical memory installed, the remaining memory will be available
as "high memory". Accessing high memory is a little more costly
than low memory, as it needs to be mapped into the kernel first.
Note that increasing the kernel address space limits the range
available to user programs, making the address space there
tighter. Selecting anything other than the default 3G/1G split
will also likely make your kernel incompatible with binary-only
kernel modules.
If you are not absolutely sure what you are doing, leave this
option alone!
config VMSPLIT_3G
bool "3G/1G user/kernel split"
config VMSPLIT_3G_OPT
depends on !X86_PAE
bool "3G/1G user/kernel split (for full 1G low memory)"
config VMSPLIT_2G
bool "2G/2G user/kernel split"
config VMSPLIT_2G_OPT
depends on !X86_PAE
bool "2G/2G user/kernel split (for full 2G low memory)"
config VMSPLIT_1G
bool "1G/3G user/kernel split"
endchoice
config PAGE_OFFSET
hex
default 0xB0000000 if VMSPLIT_3G_OPT
default 0x80000000 if VMSPLIT_2G
default 0x78000000 if VMSPLIT_2G_OPT
default 0x40000000 if VMSPLIT_1G
default 0xC0000000
depends on X86_32
config HIGHMEM
def_bool y
depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
config X86_PAE
bool "PAE (Physical Address Extension) Support"
depends on X86_32 && !HIGHMEM4G
---help---
PAE is required for NX support, and furthermore enables
larger swapspace support for non-overcommit purposes. It
has the cost of more pagetable lookup overhead, and also
consumes more pagetable space per process.
config ARCH_PHYS_ADDR_T_64BIT
def_bool X86_64 || X86_PAE
config DIRECT_GBPAGES
bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
default y
depends on X86_64
---help---
Allow the kernel linear mapping to use 1GB pages on CPUs that
support it. This can improve the kernel's performance a tiny bit by
reducing TLB pressure. If in doubt, say "Y".
# Common NUMA Features
config NUMA
bool "Numa Memory Allocation and Scheduler Support"
depends on SMP
depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
---help---
Enable NUMA (Non Uniform Memory Access) support.
The kernel will try to allocate memory used by a CPU on the
local memory controller of the CPU and add some more
NUMA awareness to the kernel.
For 64-bit this is recommended if the system is Intel Core i7
(or later), AMD Opteron, or EM64T NUMA.
For 32-bit this is only needed on (rare) 32-bit-only platforms
that support NUMA topologies, such as NUMAQ / Summit, or if you
boot a 32-bit kernel on a 64-bit NUMA platform.
Otherwise, you should say N.
comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
config K8_NUMA
def_bool y
prompt "Old style AMD Opteron NUMA detection"
depends on X86_64 && NUMA && PCI
---help---
Enable K8 NUMA node topology detection. You should say Y here if
you have a multi processor AMD K8 system. This uses an old
method to read the NUMA configuration directly from the builtin
Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
instead, which also takes priority if both are compiled in.
config X86_64_ACPI_NUMA
def_bool y
prompt "ACPI NUMA detection"
depends on X86_64 && NUMA && ACPI && PCI
select ACPI_NUMA
---help---
Enable ACPI SRAT based node topology detection.
# Some NUMA nodes have memory ranges that span
# other nodes. Even though a pfn is valid and
# between a node's start and end pfns, it may not
# reside on that node. See memmap_init_zone()
# for details.
config NODES_SPAN_OTHER_NODES
def_bool y
depends on X86_64_ACPI_NUMA
config NUMA_EMU
bool "NUMA emulation"
depends on X86_64 && NUMA
---help---
Enable NUMA emulation. A flat machine will be split
into virtual nodes when booted with "numa=fake=N", where N is the
number of nodes. This is only useful for debugging.
config NODES_SHIFT
int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
range 1 9
default "9" if MAXSMP
default "6" if X86_64
default "4" if X86_NUMAQ
default "3"
depends on NEED_MULTIPLE_NODES
---help---
Specify the maximum number of NUMA Nodes available on the target
system. Increases memory reserved to accommodate various tables.
config HAVE_ARCH_BOOTMEM
def_bool y
depends on X86_32 && NUMA
config ARCH_HAVE_MEMORY_PRESENT
def_bool y
depends on X86_32 && DISCONTIGMEM
config NEED_NODE_MEMMAP_SIZE
def_bool y
depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
config HAVE_ARCH_ALLOC_REMAP
def_bool y
depends on X86_32 && NUMA
config ARCH_FLATMEM_ENABLE
def_bool y
depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
config ARCH_DISCONTIGMEM_ENABLE
def_bool y
depends on NUMA && X86_32
config ARCH_DISCONTIGMEM_DEFAULT
def_bool y
depends on NUMA && X86_32
config ARCH_SPARSEMEM_DEFAULT
def_bool y
depends on X86_64
config ARCH_SPARSEMEM_ENABLE
def_bool y
depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
select SPARSEMEM_STATIC if X86_32
select SPARSEMEM_VMEMMAP_ENABLE if X86_64
config ARCH_SELECT_MEMORY_MODEL
def_bool y
depends on ARCH_SPARSEMEM_ENABLE
config ARCH_MEMORY_PROBE
def_bool X86_64
depends on MEMORY_HOTPLUG
source "mm/Kconfig"
config HIGHPTE
bool "Allocate 3rd-level pagetables from highmem"
depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
---help---
The VM uses one page table entry for each page of physical memory.
For systems with a lot of RAM, this can be wasteful of precious
low memory. Setting this option will put user-space page table
entries in high memory.
config X86_CHECK_BIOS_CORRUPTION
bool "Check for low memory corruption"
---help---
Periodically check for memory corruption in low memory, which
is suspected to be caused by BIOS. Even when enabled in the
configuration, it is disabled at runtime. Enable it by
setting "memory_corruption_check=1" on the kernel command
line. By default it scans the low 64k of memory every 60
seconds; see the memory_corruption_check_size and
memory_corruption_check_period parameters in
Documentation/kernel-parameters.txt to adjust this.
When enabled with the default parameters, this option has
almost no overhead, as it reserves a relatively small amount
of memory and scans it infrequently. It both detects corruption
and prevents it from affecting the running system.
It is, however, intended as a diagnostic tool; if repeatable
BIOS-originated corruption always affects the same memory,
you can use memmap= to prevent the kernel from using that
memory.
config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
bool "Set the default setting of memory_corruption_check"
depends on X86_CHECK_BIOS_CORRUPTION
default y
---help---
Set whether the default state of memory_corruption_check is
on or off.
config X86_RESERVE_LOW_64K
bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
default y
---help---
Reserve the first 64K of physical RAM on BIOSes that are known
to potentially corrupt that memory range. A numbers of BIOSes are
known to utilize this area during suspend/resume, so it must not
be used by the kernel.
Set this to N if you are absolutely sure that you trust the BIOS
to get all its memory reservations and usages right.
If you have doubts about the BIOS (e.g. suspend/resume does not
work or there's kernel crashes after certain hardware hotplug
events) and it's not AMI or Phoenix, then you might want to enable
X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
corruption patterns.
Say Y if unsure.
config MATH_EMULATION
bool
prompt "Math emulation" if X86_32
---help---
Linux can emulate a math coprocessor (used for floating point
operations) if you don't have one. 486DX and Pentium processors have
a math coprocessor built in, 486SX and 386 do not, unless you added
a 487DX or 387, respectively. (The messages during boot time can
give you some hints here ["man dmesg"].) Everyone needs either a
coprocessor or this emulation.
If you don't have a math coprocessor, you need to say Y here; if you
say Y here even though you have a coprocessor, the coprocessor will
be used nevertheless. (This behavior can be changed with the kernel
command line option "no387", which comes handy if your coprocessor
is broken. Try "man bootparam" or see the documentation of your boot
loader (lilo or loadlin) about how to pass options to the kernel at
boot time.) This means that it is a good idea to say Y here if you
intend to use this kernel on different machines.
More information about the internals of the Linux math coprocessor
emulation can be found in <file:arch/x86/math-emu/README>.
If you are not sure, say Y; apart from resulting in a 66 KB bigger
kernel, it won't hurt.
config MTRR
bool "MTRR (Memory Type Range Register) support"
---help---
On Intel P6 family processors (Pentium Pro, Pentium II and later)
the Memory Type Range Registers (MTRRs) may be used to control
processor access to memory ranges. This is most useful if you have
a video (VGA) card on a PCI or AGP bus. Enabling write-combining
allows bus write transfers to be combined into a larger transfer
before bursting over the PCI/AGP bus. This can increase performance
of image write operations 2.5 times or more. Saying Y here creates a
/proc/mtrr file which may be used to manipulate your processor's
MTRRs. Typically the X server should use this.
This code has a reasonably generic interface so that similar
control registers on other processors can be easily supported
as well:
The Cyrix 6x86, 6x86MX and M II processors have Address Range
Registers (ARRs) which provide a similar functionality to MTRRs. For
these, the ARRs are used to emulate the MTRRs.
The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
write-combining. All of these processors are supported by this code
and it makes sense to say Y here if you have one of them.
Saying Y here also fixes a problem with buggy SMP BIOSes which only
set the MTRRs for the boot CPU and not for the secondary CPUs. This
can lead to all sorts of problems, so it's good to say Y here.
You can safely say Y even if your machine doesn't have MTRRs, you'll
just add about 9 KB to your kernel.
See <file:Documentation/x86/mtrr.txt> for more information.
config MTRR_SANITIZER
def_bool y
prompt "MTRR cleanup support"
depends on MTRR
---help---
Convert MTRR layout from continuous to discrete, so X drivers can
add writeback entries.
Can be disabled with disable_mtrr_cleanup on the kernel command line.
The largest mtrr entry size for a continuous block can be set with
mtrr_chunk_size.
If unsure, say Y.
config MTRR_SANITIZER_ENABLE_DEFAULT
int "MTRR cleanup enable value (0-1)"
range 0 1
default "0"
depends on MTRR_SANITIZER
---help---
Enable mtrr cleanup default value
config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
int "MTRR cleanup spare reg num (0-7)"
range 0 7
default "1"
depends on MTRR_SANITIZER
---help---
mtrr cleanup spare entries default, it can be changed via
mtrr_spare_reg_nr=N on the kernel command line.
config X86_PAT
bool
prompt "x86 PAT support"
depends on MTRR
---help---
Use PAT attributes to setup page level cache control.
PATs are the modern equivalents of MTRRs and are much more
flexible than MTRRs.
Say N here if you see bootup problems (boot crash, boot hang,
spontaneous reboots) or a non-working video driver.
If unsure, say Y.
config EFI
bool "EFI runtime service support"
depends on ACPI
---help---
This enables the kernel to use EFI runtime services that are
available (such as the EFI variable services).
This option is only useful on systems that have EFI firmware.
In addition, you should use the latest ELILO loader available
at <http://elilo.sourceforge.net> in order to take advantage
of EFI runtime services. However, even with this option, the
resultant kernel should continue to boot on existing non-EFI
platforms.
config SECCOMP
def_bool y
prompt "Enable seccomp to safely compute untrusted bytecode"
---help---
This kernel feature is useful for number crunching applications
that may need to compute untrusted bytecode during their
execution. By using pipes or other transports made available to
the process as file descriptors supporting the read/write
syscalls, it's possible to isolate those applications in
their own address space using seccomp. Once seccomp is
enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
and the task is only allowed to execute a few safe syscalls
defined by each seccomp mode.
If unsure, say Y. Only embedded should say N here.
config CC_STACKPROTECTOR_ALL
bool
config CC_STACKPROTECTOR
bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
select CC_STACKPROTECTOR_ALL
---help---
This option turns on the -fstack-protector GCC feature. This
feature puts, at the beginning of functions, a canary value on
the stack just before the return address, and validates
the value just before actually returning. Stack based buffer
overflows (that need to overwrite this return address) now also
overwrite the canary, which gets detected and the attack is then
neutralized via a kernel panic.
This feature requires gcc version 4.2 or above, or a distribution
gcc with the feature backported. Older versions are automatically
detected and for those versions, this configuration option is
ignored. (and a warning is printed during bootup)
source kernel/Kconfig.hz
config KEXEC
bool "kexec system call"
---help---
kexec is a system call that implements the ability to shutdown your
current kernel, and to start another kernel. It is like a reboot
but it is independent of the system firmware. And like a reboot
you can start any kernel with it, not just Linux.
The name comes from the similarity to the exec system call.
It is an ongoing process to be certain the hardware in a machine
is properly shutdown, so do not be surprised if this code does not
initially work for you. It may help to enable device hotplugging
support. As of this writing the exact hardware interface is
strongly in flux, so no good recommendation can be made.
config CRASH_DUMP
bool "kernel crash dumps"
depends on X86_64 || (X86_32 && HIGHMEM)
---help---
Generate crash dump after being started by kexec.
This should be normally only set in special crash dump kernels
which are loaded in the main kernel with kexec-tools into
a specially reserved region and then later executed after
a crash by kdump/kexec. The crash dump kernel must be compiled
to a memory address not used by the main kernel or BIOS using
PHYSICAL_START, or it must be built as a relocatable image
(CONFIG_RELOCATABLE=y).
For more details see Documentation/kdump/kdump.txt
config KEXEC_JUMP
bool "kexec jump (EXPERIMENTAL)"
depends on EXPERIMENTAL
depends on KEXEC && HIBERNATION
---help---
Jump between original kernel and kexeced kernel and invoke
code in physical address mode via KEXEC
config PHYSICAL_START
hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
default "0x1000000"
---help---
This gives the physical address where the kernel is loaded.
If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
bzImage will decompress itself to above physical address and
run from there. Otherwise, bzImage will run from the address where
it has been loaded by the boot loader and will ignore above physical
address.
In normal kdump cases one does not have to set/change this option
as now bzImage can be compiled as a completely relocatable image
(CONFIG_RELOCATABLE=y) and be used to load and run from a different
address. This option is mainly useful for the folks who don't want
to use a bzImage for capturing the crash dump and want to use a
vmlinux instead. vmlinux is not relocatable hence a kernel needs
to be specifically compiled to run from a specific memory area
(normally a reserved region) and this option comes handy.
So if you are using bzImage for capturing the crash dump,
leave the value here unchanged to 0x1000000 and set
CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
for capturing the crash dump change this value to start of
the reserved region. In other words, it can be set based on
the "X" value as specified in the "crashkernel=YM@XM"
command line boot parameter passed to the panic-ed
kernel. Please take a look at Documentation/kdump/kdump.txt
for more details about crash dumps.
Usage of bzImage for capturing the crash dump is recommended as
one does not have to build two kernels. Same kernel can be used
as production kernel and capture kernel. Above option should have
gone away after relocatable bzImage support is introduced. But it
is present because there are users out there who continue to use
vmlinux for dump capture. This option should go away down the
line.
Don't change this unless you know what you are doing.
config RELOCATABLE
bool "Build a relocatable kernel"
default y
---help---
This builds a kernel image that retains relocation information
so it can be loaded someplace besides the default 1MB.
The relocations tend to make the kernel binary about 10% larger,
but are discarded at runtime.
One use is for the kexec on panic case where the recovery kernel
must live at a different physical address than the primary
kernel.
Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
it has been loaded at and the compile time physical address
(CONFIG_PHYSICAL_START) is ignored.
# Relocation on x86-32 needs some additional build support
config X86_NEED_RELOCS
def_bool y
depends on X86_32 && RELOCATABLE
config PHYSICAL_ALIGN
hex
prompt "Alignment value to which kernel should be aligned" if X86_32
default "0x1000000"
range 0x2000 0x1000000
---help---
This value puts the alignment restrictions on physical address
where kernel is loaded and run from. Kernel is compiled for an
address which meets above alignment restriction.
If bootloader loads the kernel at a non-aligned address and
CONFIG_RELOCATABLE is set, kernel will move itself to nearest
address aligned to above value and run from there.
If bootloader loads the kernel at a non-aligned address and
CONFIG_RELOCATABLE is not set, kernel will ignore the run time
load address and decompress itself to the address it has been
compiled for and run from there. The address for which kernel is
compiled already meets above alignment restrictions. Hence the
end result is that kernel runs from a physical address meeting
above alignment restrictions.
Don't change this unless you know what you are doing.
config HOTPLUG_CPU
bool "Support for hot-pluggable CPUs"
depends on SMP && HOTPLUG
---help---
Say Y here to allow turning CPUs off and on. CPUs can be
controlled through /sys/devices/system/cpu.
( Note: power management support will enable this option
automatically on SMP systems. )
Say N if you want to disable CPU hotplug.
config COMPAT_VDSO
def_bool y
prompt "Compat VDSO support"
depends on X86_32 || IA32_EMULATION
---help---
Map the 32-bit VDSO to the predictable old-style address too.
---help---
Say N here if you are running a sufficiently recent glibc
version (2.3.3 or later), to remove the high-mapped
VDSO mapping and to exclusively use the randomized VDSO.
If unsure, say Y.
config CMDLINE_BOOL
bool "Built-in kernel command line"
default n
---help---
Allow for specifying boot arguments to the kernel at
build time. On some systems (e.g. embedded ones), it is
necessary or convenient to provide some or all of the
kernel boot arguments with the kernel itself (that is,
to not rely on the boot loader to provide them.)
To compile command line arguments into the kernel,
set this option to 'Y', then fill in the
the boot arguments in CONFIG_CMDLINE.
Systems with fully functional boot loaders (i.e. non-embedded)
should leave this option set to 'N'.
config CMDLINE
string "Built-in kernel command string"
depends on CMDLINE_BOOL
default ""
---help---
Enter arguments here that should be compiled into the kernel
image and used at boot time. If the boot loader provides a
command line at boot time, it is appended to this string to
form the full kernel command line, when the system boots.
However, you can use the CONFIG_CMDLINE_OVERRIDE option to
change this behavior.
In most cases, the command line (whether built-in or provided
by the boot loader) should specify the device for the root
file system.
config CMDLINE_OVERRIDE
bool "Built-in command line overrides boot loader arguments"
default n
depends on CMDLINE_BOOL
---help---
Set this option to 'Y' to have the kernel ignore the boot loader
command line, and use ONLY the built-in command line.
This is used to work around broken boot loaders. This should
be set to 'N' under normal conditions.
endmenu
config ARCH_ENABLE_MEMORY_HOTPLUG
def_bool y
depends on X86_64 || (X86_32 && HIGHMEM)
config ARCH_ENABLE_MEMORY_HOTREMOVE
def_bool y
depends on MEMORY_HOTPLUG
config HAVE_ARCH_EARLY_PFN_TO_NID
def_bool X86_64
depends on NUMA
menu "Power management and ACPI options"
config ARCH_HIBERNATION_HEADER
def_bool y
depends on X86_64 && HIBERNATION
source "kernel/power/Kconfig"
source "drivers/acpi/Kconfig"
config X86_APM_BOOT
bool
default y
depends on APM || APM_MODULE
menuconfig APM
tristate "APM (Advanced Power Management) BIOS support"
depends on X86_32 && PM_SLEEP
---help---
APM is a BIOS specification for saving power using several different
techniques. This is mostly useful for battery powered laptops with
APM compliant BIOSes. If you say Y here, the system time will be
reset after a RESUME operation, the /proc/apm device will provide
battery status information, and user-space programs will receive
notification of APM "events" (e.g. battery status change).
If you select "Y" here, you can disable actual use of the APM
BIOS by passing the "apm=off" option to the kernel at boot time.
Note that the APM support is almost completely disabled for
machines with more than one CPU.
In order to use APM, you will need supporting software. For location
and more information, read <file:Documentation/power/pm.txt> and the
Battery Powered Linux mini-HOWTO, available from
<http://www.tldp.org/docs.html#howto>.
This driver does not spin down disk drives (see the hdparm(8)
manpage ("man 8 hdparm") for that), and it doesn't turn off
VESA-compliant "green" monitors.
This driver does not support the TI 4000M TravelMate and the ACER
486/DX4/75 because they don't have compliant BIOSes. Many "green"
desktop machines also don't have compliant BIOSes, and this driver
may cause those machines to panic during the boot phase.
Generally, if you don't have a battery in your machine, there isn't
much point in using this driver and you should say N. If you get
random kernel OOPSes or reboots that don't seem to be related to
anything, try disabling/enabling this option (or disabling/enabling
APM in your BIOS).
Some other things you should try when experiencing seemingly random,
"weird" problems:
1) make sure that you have enough swap space and that it is
enabled.
2) pass the "no-hlt" option to the kernel
3) switch on floating point emulation in the kernel and pass
the "no387" option to the kernel
4) pass the "floppy=nodma" option to the kernel
5) pass the "mem=4M" option to the kernel (thereby disabling
all but the first 4 MB of RAM)
6) make sure that the CPU is not over clocked.
7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
8) disable the cache from your BIOS settings
9) install a fan for the video card or exchange video RAM
10) install a better fan for the CPU
11) exchange RAM chips
12) exchange the motherboard.
To compile this driver as a module, choose M here: the
module will be called apm.
if APM
config APM_IGNORE_USER_SUSPEND
bool "Ignore USER SUSPEND"
---help---
This option will ignore USER SUSPEND requests. On machines with a
compliant APM BIOS, you want to say N. However, on the NEC Versa M
series notebooks, it is necessary to say Y because of a BIOS bug.
config APM_DO_ENABLE
bool "Enable PM at boot time"
---help---
Enable APM features at boot time. From page 36 of the APM BIOS
specification: "When disabled, the APM BIOS does not automatically
power manage devices, enter the Standby State, enter the Suspend
State, or take power saving steps in response to CPU Idle calls."
This driver will make CPU Idle calls when Linux is idle (unless this
feature is turned off -- see "Do CPU IDLE calls", below). This
should always save battery power, but more complicated APM features
will be dependent on your BIOS implementation. You may need to turn
this option off if your computer hangs at boot time when using APM
support, or if it beeps continuously instead of suspending. Turn
this off if you have a NEC UltraLite Versa 33/C or a Toshiba
T400CDT. This is off by default since most machines do fine without
this feature.
config APM_CPU_IDLE
bool "Make CPU Idle calls when idle"
---help---
Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
On some machines, this can activate improved power savings, such as
a slowed CPU clock rate, when the machine is idle. These idle calls
are made after the idle loop has run for some length of time (e.g.,
333 mS). On some machines, this will cause a hang at boot time or
whenever the CPU becomes idle. (On machines with more than one CPU,
this option does nothing.)
config APM_DISPLAY_BLANK
bool "Enable console blanking using APM"
---help---
Enable console blanking using the APM. Some laptops can use this to
turn off the LCD backlight when the screen blanker of the Linux
virtual console blanks the screen. Note that this is only used by
the virtual console screen blanker, and won't turn off the backlight
when using the X Window system. This also doesn't have anything to
do with your VESA-compliant power-saving monitor. Further, this
option doesn't work for all laptops -- it might not turn off your
backlight at all, or it might print a lot of errors to the console,
especially if you are using gpm.
config APM_ALLOW_INTS
bool "Allow interrupts during APM BIOS calls"
---help---
Normally we disable external interrupts while we are making calls to
the APM BIOS as a measure to lessen the effects of a badly behaving
BIOS implementation. The BIOS should reenable interrupts if it
needs to. Unfortunately, some BIOSes do not -- especially those in
many of the newer IBM Thinkpads. If you experience hangs when you
suspend, try setting this to Y. Otherwise, say N.
endif # APM
source "arch/x86/kernel/cpu/cpufreq/Kconfig"
source "drivers/cpuidle/Kconfig"
source "drivers/idle/Kconfig"
endmenu
menu "Bus options (PCI etc.)"
config PCI
bool "PCI support"
default y
select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
---help---
Find out whether you have a PCI motherboard. PCI is the name of a
bus system, i.e. the way the CPU talks to the other stuff inside
your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
VESA. If you have PCI, say Y, otherwise N.
choice
prompt "PCI access mode"
depends on X86_32 && PCI
default PCI_GOANY
---help---
On PCI systems, the BIOS can be used to detect the PCI devices and
determine their configuration. However, some old PCI motherboards
have BIOS bugs and may crash if this is done. Also, some embedded
PCI-based systems don't have any BIOS at all. Linux can also try to
detect the PCI hardware directly without using the BIOS.
With this option, you can specify how Linux should detect the
PCI devices. If you choose "BIOS", the BIOS will be used,
if you choose "Direct", the BIOS won't be used, and if you
choose "MMConfig", then PCI Express MMCONFIG will be used.
If you choose "Any", the kernel will try MMCONFIG, then the
direct access method and falls back to the BIOS if that doesn't
work. If unsure, go with the default, which is "Any".
config PCI_GOBIOS
bool "BIOS"
config PCI_GOMMCONFIG
bool "MMConfig"
config PCI_GODIRECT
bool "Direct"
config PCI_GOOLPC
bool "OLPC"
depends on OLPC
config PCI_GOANY
bool "Any"
endchoice
config PCI_BIOS
def_bool y
depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
config PCI_DIRECT
def_bool y
depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
config PCI_MMCONFIG
def_bool y
depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
config PCI_OLPC
def_bool y
depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
config PCI_DOMAINS
def_bool y
depends on PCI
config PCI_MMCONFIG
bool "Support mmconfig PCI config space access"
depends on X86_64 && PCI && ACPI
config DMAR
bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
depends on PCI_MSI && ACPI && EXPERIMENTAL
help
DMA remapping (DMAR) devices support enables independent address
translations for Direct Memory Access (DMA) from devices.
These DMA remapping devices are reported via ACPI tables
and include PCI device scope covered by these DMA
remapping devices.
config DMAR_DEFAULT_ON
def_bool y
prompt "Enable DMA Remapping Devices by default"
depends on DMAR
help
Selecting this option will enable a DMAR device at boot time if
one is found. If this option is not selected, DMAR support can
be enabled by passing intel_iommu=on to the kernel. It is
recommended you say N here while the DMAR code remains
experimental.
config DMAR_BROKEN_GFX_WA
def_bool n
prompt "Workaround broken graphics drivers (going away soon)"
depends on DMAR
---help---
Current Graphics drivers tend to use physical address
for DMA and avoid using DMA APIs. Setting this config
option permits the IOMMU driver to set a unity map for
all the OS-visible memory. Hence the driver can continue
to use physical addresses for DMA, at least until this
option is removed in the 2.6.32 kernel.
config DMAR_FLOPPY_WA
def_bool y
depends on DMAR
---help---
Floppy disk drivers are known to bypass DMA API calls
thereby failing to work when IOMMU is enabled. This
workaround will setup a 1:1 mapping for the first
16MiB to make floppy (an ISA device) work.
config INTR_REMAP
bool "Support for Interrupt Remapping (EXPERIMENTAL)"
depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
---help---
Supports Interrupt remapping for IO-APIC and MSI devices.
To use x2apic mode in the CPU's which support x2APIC enhancements or
to support platforms with CPU's having > 8 bit APIC ID, say Y.
source "drivers/pci/pcie/Kconfig"
source "drivers/pci/Kconfig"
# x86_64 have no ISA slots, but do have ISA-style DMA.
config ISA_DMA_API
def_bool y
if X86_32
config ISA
bool "ISA support"
---help---
Find out whether you have ISA slots on your motherboard. ISA is the
name of a bus system, i.e. the way the CPU talks to the other stuff
inside your box. Other bus systems are PCI, EISA, MicroChannel
(MCA) or VESA. ISA is an older system, now being displaced by PCI;
newer boards don't support it. If you have ISA, say Y, otherwise N.
config EISA
bool "EISA support"
depends on ISA
---help---
The Extended Industry Standard Architecture (EISA) bus was
developed as an open alternative to the IBM MicroChannel bus.
The EISA bus provided some of the features of the IBM MicroChannel
bus while maintaining backward compatibility with cards made for
the older ISA bus. The EISA bus saw limited use between 1988 and
1995 when it was made obsolete by the PCI bus.
Say Y here if you are building a kernel for an EISA-based machine.
Otherwise, say N.
source "drivers/eisa/Kconfig"
config MCA
bool "MCA support"
---help---
MicroChannel Architecture is found in some IBM PS/2 machines and
laptops. It is a bus system similar to PCI or ISA. See
<file:Documentation/mca.txt> (and especially the web page given
there) before attempting to build an MCA bus kernel.
source "drivers/mca/Kconfig"
config SCx200
tristate "NatSemi SCx200 support"
---help---
This provides basic support for National Semiconductor's
(now AMD's) Geode processors. The driver probes for the
PCI-IDs of several on-chip devices, so its a good dependency
for other scx200_* drivers.
If compiled as a module, the driver is named scx200.
config SCx200HR_TIMER
tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
depends on SCx200 && GENERIC_TIME
default y
---help---
This driver provides a clocksource built upon the on-chip
27MHz high-resolution timer. Its also a workaround for
NSC Geode SC-1100's buggy TSC, which loses time when the
processor goes idle (as is done by the scheduler). The
other workaround is idle=poll boot option.
config GEODE_MFGPT_TIMER
def_bool y
prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
---help---
This driver provides a clock event source based on the MFGPT
timer(s) in the CS5535 and CS5536 companion chip for the geode.
MFGPTs have a better resolution and max interval than the
generic PIT, and are suitable for use as high-res timers.
config OLPC
bool "One Laptop Per Child support"
default n
---help---
Add support for detecting the unique features of the OLPC
XO hardware.
endif # X86_32
config K8_NB
def_bool y
depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
source "drivers/pcmcia/Kconfig"
source "drivers/pci/hotplug/Kconfig"
endmenu
menu "Executable file formats / Emulations"
source "fs/Kconfig.binfmt"
config IA32_EMULATION
bool "IA32 Emulation"
depends on X86_64
select COMPAT_BINFMT_ELF
---help---
Include code to run 32-bit programs under a 64-bit kernel. You should
likely turn this on, unless you're 100% sure that you don't have any
32-bit programs left.
config IA32_AOUT
tristate "IA32 a.out support"
depends on IA32_EMULATION
---help---
Support old a.out binaries in the 32bit emulation.
config COMPAT
def_bool y
depends on IA32_EMULATION
config COMPAT_FOR_U64_ALIGNMENT
def_bool COMPAT
depends on X86_64
config SYSVIPC_COMPAT
def_bool y
depends on COMPAT && SYSVIPC
endmenu
config HAVE_ATOMIC_IOMAP
def_bool y
depends on X86_32
source "net/Kconfig"
source "drivers/Kconfig"
source "drivers/firmware/Kconfig"
source "fs/Kconfig"
source "arch/x86/Kconfig.debug"
source "security/Kconfig"
source "crypto/Kconfig"
source "arch/x86/kvm/Kconfig"
source "lib/Kconfig"
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