| blob | a5d100cf8ed63fda50be0a431cf51289b336cb33 |
1 # Select 32 or 64 bit
2 config 64BIT
3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH != "i386"
5 ---help---
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
9 config X86_32
10 def_bool y
11 depends on !64BIT
12 select CLKSRC_I8253
13 select HAVE_UID16
15 config X86_64
16 def_bool y
17 depends on 64BIT
18 select X86_DEV_DMA_OPS
19 select ARCH_USE_CMPXCHG_LOCKREF
21 ### Arch settings
22 config X86
23 def_bool y
24 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
25 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
26 select ARCH_HAS_FAST_MULTIPLIER
27 select ARCH_MIGHT_HAVE_PC_PARPORT
28 select ARCH_MIGHT_HAVE_PC_SERIO
29 select HAVE_AOUT if X86_32
30 select HAVE_UNSTABLE_SCHED_CLOCK
31 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
32 select ARCH_SUPPORTS_INT128 if X86_64
33 select HAVE_IDE
34 select HAVE_OPROFILE
35 select HAVE_PCSPKR_PLATFORM
36 select HAVE_PERF_EVENTS
37 select HAVE_IOREMAP_PROT
38 select HAVE_KPROBES
39 select HAVE_MEMBLOCK
40 select HAVE_MEMBLOCK_NODE_MAP
41 select ARCH_DISCARD_MEMBLOCK
42 select ARCH_WANT_OPTIONAL_GPIOLIB
43 select ARCH_WANT_FRAME_POINTERS
44 select HAVE_DMA_ATTRS
45 select HAVE_DMA_CONTIGUOUS
46 select HAVE_KRETPROBES
47 select GENERIC_EARLY_IOREMAP
48 select HAVE_OPTPROBES
49 select HAVE_KPROBES_ON_FTRACE
50 select HAVE_FTRACE_MCOUNT_RECORD
51 select HAVE_FENTRY if X86_64
52 select HAVE_C_RECORDMCOUNT
53 select HAVE_DYNAMIC_FTRACE
54 select HAVE_DYNAMIC_FTRACE_WITH_REGS
55 select HAVE_FUNCTION_TRACER
56 select HAVE_FUNCTION_GRAPH_TRACER
57 select HAVE_FUNCTION_GRAPH_FP_TEST
58 select HAVE_SYSCALL_TRACEPOINTS
59 select SYSCTL_EXCEPTION_TRACE
60 select HAVE_KVM
61 select HAVE_ARCH_KGDB
62 select HAVE_ARCH_TRACEHOOK
63 select HAVE_GENERIC_DMA_COHERENT if X86_32
64 select HAVE_EFFICIENT_UNALIGNED_ACCESS
65 select USER_STACKTRACE_SUPPORT
66 select HAVE_REGS_AND_STACK_ACCESS_API
67 select HAVE_DMA_API_DEBUG
68 select HAVE_KERNEL_GZIP
69 select HAVE_KERNEL_BZIP2
70 select HAVE_KERNEL_LZMA
71 select HAVE_KERNEL_XZ
72 select HAVE_KERNEL_LZO
73 select HAVE_KERNEL_LZ4
74 select HAVE_HW_BREAKPOINT
75 select HAVE_MIXED_BREAKPOINTS_REGS
76 select PERF_EVENTS
77 select HAVE_PERF_EVENTS_NMI
78 select HAVE_PERF_REGS
79 select HAVE_PERF_USER_STACK_DUMP
80 select HAVE_DEBUG_KMEMLEAK
81 select ANON_INODES
82 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
83 select HAVE_CMPXCHG_LOCAL
84 select HAVE_CMPXCHG_DOUBLE
85 select HAVE_ARCH_KMEMCHECK
86 select HAVE_USER_RETURN_NOTIFIER
87 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
88 select HAVE_ARCH_JUMP_LABEL
89 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
90 select SPARSE_IRQ
91 select GENERIC_FIND_FIRST_BIT
92 select GENERIC_IRQ_PROBE
93 select GENERIC_PENDING_IRQ if SMP
94 select GENERIC_IRQ_SHOW
95 select GENERIC_CLOCKEVENTS_MIN_ADJUST
96 select IRQ_FORCED_THREADING
97 select HAVE_BPF_JIT if X86_64
98 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
99 select ARCH_HAS_SG_CHAIN
100 select CLKEVT_I8253
101 select ARCH_HAVE_NMI_SAFE_CMPXCHG
102 select GENERIC_IOMAP
103 select DCACHE_WORD_ACCESS
104 select GENERIC_SMP_IDLE_THREAD
105 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
106 select HAVE_ARCH_SECCOMP_FILTER
107 select BUILDTIME_EXTABLE_SORT
108 select GENERIC_CMOS_UPDATE
109 select HAVE_ARCH_SOFT_DIRTY if X86_64
110 select CLOCKSOURCE_WATCHDOG
111 select GENERIC_CLOCKEVENTS
112 select ARCH_CLOCKSOURCE_DATA
113 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
114 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
115 select GENERIC_TIME_VSYSCALL
116 select GENERIC_STRNCPY_FROM_USER
117 select GENERIC_STRNLEN_USER
118 select HAVE_CONTEXT_TRACKING if X86_64
119 select HAVE_IRQ_TIME_ACCOUNTING
120 select VIRT_TO_BUS
121 select MODULES_USE_ELF_REL if X86_32
122 select MODULES_USE_ELF_RELA if X86_64
123 select CLONE_BACKWARDS if X86_32
124 select ARCH_USE_BUILTIN_BSWAP
125 select ARCH_USE_QUEUE_RWLOCK
126 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
127 select OLD_SIGACTION if X86_32
128 select COMPAT_OLD_SIGACTION if IA32_EMULATION
129 select RTC_LIB
130 select HAVE_DEBUG_STACKOVERFLOW
131 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
132 select HAVE_CC_STACKPROTECTOR
133 select GENERIC_CPU_AUTOPROBE
134 select HAVE_ARCH_AUDITSYSCALL
135 select ARCH_SUPPORTS_ATOMIC_RMW
136 select HAVE_ACPI_APEI if ACPI
137 select HAVE_ACPI_APEI_NMI if ACPI
138 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
139 select X86_FEATURE_NAMES if PROC_FS
141 config INSTRUCTION_DECODER
142 def_bool y
143 depends on KPROBES || PERF_EVENTS || UPROBES
145 config PERF_EVENTS_INTEL_UNCORE
146 def_bool y
147 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
149 config OUTPUT_FORMAT
150 string
151 default "elf32-i386" if X86_32
152 default "elf64-x86-64" if X86_64
154 config ARCH_DEFCONFIG
155 string
156 default "arch/x86/configs/i386_defconfig" if X86_32
157 default "arch/x86/configs/x86_64_defconfig" if X86_64
159 config LOCKDEP_SUPPORT
160 def_bool y
162 config STACKTRACE_SUPPORT
163 def_bool y
165 config HAVE_LATENCYTOP_SUPPORT
166 def_bool y
168 config MMU
169 def_bool y
171 config SBUS
172 bool
174 config NEED_DMA_MAP_STATE
175 def_bool y
176 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
178 config NEED_SG_DMA_LENGTH
179 def_bool y
181 config GENERIC_ISA_DMA
182 def_bool y
183 depends on ISA_DMA_API
185 config GENERIC_BUG
186 def_bool y
187 depends on BUG
188 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
190 config GENERIC_BUG_RELATIVE_POINTERS
191 bool
193 config GENERIC_HWEIGHT
194 def_bool y
196 config ARCH_MAY_HAVE_PC_FDC
197 def_bool y
198 depends on ISA_DMA_API
200 config RWSEM_XCHGADD_ALGORITHM
201 def_bool y
203 config GENERIC_CALIBRATE_DELAY
204 def_bool y
206 config ARCH_HAS_CPU_RELAX
207 def_bool y
209 config ARCH_HAS_CACHE_LINE_SIZE
210 def_bool y
212 config HAVE_SETUP_PER_CPU_AREA
213 def_bool y
215 config NEED_PER_CPU_EMBED_FIRST_CHUNK
216 def_bool y
218 config NEED_PER_CPU_PAGE_FIRST_CHUNK
219 def_bool y
221 config ARCH_HIBERNATION_POSSIBLE
222 def_bool y
224 config ARCH_SUSPEND_POSSIBLE
225 def_bool y
227 config ARCH_WANT_HUGE_PMD_SHARE
228 def_bool y
230 config ARCH_WANT_GENERAL_HUGETLB
231 def_bool y
233 config ZONE_DMA32
234 bool
235 default X86_64
237 config AUDIT_ARCH
238 bool
239 default X86_64
241 config ARCH_SUPPORTS_OPTIMIZED_INLINING
242 def_bool y
244 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
245 def_bool y
247 config HAVE_INTEL_TXT
248 def_bool y
249 depends on INTEL_IOMMU && ACPI
251 config X86_32_SMP
252 def_bool y
253 depends on X86_32 && SMP
255 config X86_64_SMP
256 def_bool y
257 depends on X86_64 && SMP
259 config X86_HT
260 def_bool y
261 depends on SMP
263 config X86_32_LAZY_GS
264 def_bool y
265 depends on X86_32 && !CC_STACKPROTECTOR
267 config ARCH_HWEIGHT_CFLAGS
268 string
269 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
270 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
272 config ARCH_SUPPORTS_UPROBES
273 def_bool y
275 config FIX_EARLYCON_MEM
276 def_bool y
278 source "init/Kconfig"
279 source "kernel/Kconfig.freezer"
281 menu "Processor type and features"
283 config ZONE_DMA
284 bool "DMA memory allocation support" if EXPERT
285 default y
286 help
287 DMA memory allocation support allows devices with less than 32-bit
288 addressing to allocate within the first 16MB of address space.
289 Disable if no such devices will be used.
291 If unsure, say Y.
293 config SMP
294 bool "Symmetric multi-processing support"
295 ---help---
296 This enables support for systems with more than one CPU. If you have
297 a system with only one CPU, say N. If you have a system with more
298 than one CPU, say Y.
300 If you say N here, the kernel will run on uni- and multiprocessor
301 machines, but will use only one CPU of a multiprocessor machine. If
302 you say Y here, the kernel will run on many, but not all,
303 uniprocessor machines. On a uniprocessor machine, the kernel
304 will run faster if you say N here.
306 Note that if you say Y here and choose architecture "586" or
307 "Pentium" under "Processor family", the kernel will not work on 486
308 architectures. Similarly, multiprocessor kernels for the "PPro"
309 architecture may not work on all Pentium based boards.
311 People using multiprocessor machines who say Y here should also say
312 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
313 Management" code will be disabled if you say Y here.
315 See also <file:Documentation/x86/i386/IO-APIC.txt>,
316 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
317 <http://www.tldp.org/docs.html#howto>.
319 If you don't know what to do here, say N.
321 config X86_FEATURE_NAMES
322 bool "Processor feature human-readable names" if EMBEDDED
323 default y
324 ---help---
325 This option compiles in a table of x86 feature bits and corresponding
326 names. This is required to support /proc/cpuinfo and a few kernel
327 messages. You can disable this to save space, at the expense of
328 making those few kernel messages show numeric feature bits instead.
330 If in doubt, say Y.
332 config X86_X2APIC
333 bool "Support x2apic"
334 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
335 ---help---
336 This enables x2apic support on CPUs that have this feature.
338 This allows 32-bit apic IDs (so it can support very large systems),
339 and accesses the local apic via MSRs not via mmio.
341 If you don't know what to do here, say N.
343 config X86_MPPARSE
344 bool "Enable MPS table" if ACPI || SFI
345 default y
346 depends on X86_LOCAL_APIC
347 ---help---
348 For old smp systems that do not have proper acpi support. Newer systems
349 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
351 config X86_BIGSMP
352 bool "Support for big SMP systems with more than 8 CPUs"
353 depends on X86_32 && SMP
354 ---help---
355 This option is needed for the systems that have more than 8 CPUs
357 config GOLDFISH
358 def_bool y
359 depends on X86_GOLDFISH
361 if X86_32
362 config X86_EXTENDED_PLATFORM
363 bool "Support for extended (non-PC) x86 platforms"
364 default y
365 ---help---
366 If you disable this option then the kernel will only support
367 standard PC platforms. (which covers the vast majority of
368 systems out there.)
370 If you enable this option then you'll be able to select support
371 for the following (non-PC) 32 bit x86 platforms:
372 Goldfish (Android emulator)
373 AMD Elan
374 RDC R-321x SoC
375 SGI 320/540 (Visual Workstation)
376 STA2X11-based (e.g. Northville)
377 Moorestown MID devices
379 If you have one of these systems, or if you want to build a
380 generic distribution kernel, say Y here - otherwise say N.
381 endif
383 if X86_64
384 config X86_EXTENDED_PLATFORM
385 bool "Support for extended (non-PC) x86 platforms"
386 default y
387 ---help---
388 If you disable this option then the kernel will only support
389 standard PC platforms. (which covers the vast majority of
390 systems out there.)
392 If you enable this option then you'll be able to select support
393 for the following (non-PC) 64 bit x86 platforms:
394 Numascale NumaChip
395 ScaleMP vSMP
396 SGI Ultraviolet
398 If you have one of these systems, or if you want to build a
399 generic distribution kernel, say Y here - otherwise say N.
400 endif
401 # This is an alphabetically sorted list of 64 bit extended platforms
402 # Please maintain the alphabetic order if and when there are additions
403 config X86_NUMACHIP
404 bool "Numascale NumaChip"
405 depends on X86_64
406 depends on X86_EXTENDED_PLATFORM
407 depends on NUMA
408 depends on SMP
409 depends on X86_X2APIC
410 depends on PCI_MMCONFIG
411 ---help---
412 Adds support for Numascale NumaChip large-SMP systems. Needed to
413 enable more than ~168 cores.
414 If you don't have one of these, you should say N here.
416 config X86_VSMP
417 bool "ScaleMP vSMP"
418 select HYPERVISOR_GUEST
419 select PARAVIRT
420 depends on X86_64 && PCI
421 depends on X86_EXTENDED_PLATFORM
422 depends on SMP
423 ---help---
424 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
425 supposed to run on these EM64T-based machines. Only choose this option
426 if you have one of these machines.
428 config X86_UV
429 bool "SGI Ultraviolet"
430 depends on X86_64
431 depends on X86_EXTENDED_PLATFORM
432 depends on NUMA
433 depends on X86_X2APIC
434 ---help---
435 This option is needed in order to support SGI Ultraviolet systems.
436 If you don't have one of these, you should say N here.
438 # Following is an alphabetically sorted list of 32 bit extended platforms
439 # Please maintain the alphabetic order if and when there are additions
441 config X86_GOLDFISH
442 bool "Goldfish (Virtual Platform)"
443 depends on X86_EXTENDED_PLATFORM
444 ---help---
445 Enable support for the Goldfish virtual platform used primarily
446 for Android development. Unless you are building for the Android
447 Goldfish emulator say N here.
449 config X86_INTEL_CE
450 bool "CE4100 TV platform"
451 depends on PCI
452 depends on PCI_GODIRECT
453 depends on X86_IO_APIC
454 depends on X86_32
455 depends on X86_EXTENDED_PLATFORM
456 select X86_REBOOTFIXUPS
457 select OF
458 select OF_EARLY_FLATTREE
459 select IRQ_DOMAIN
460 ---help---
461 Select for the Intel CE media processor (CE4100) SOC.
462 This option compiles in support for the CE4100 SOC for settop
463 boxes and media devices.
465 config X86_INTEL_MID
466 bool "Intel MID platform support"
467 depends on X86_32
468 depends on X86_EXTENDED_PLATFORM
469 depends on X86_PLATFORM_DEVICES
470 depends on PCI
471 depends on PCI_GOANY
472 depends on X86_IO_APIC
473 select SFI
474 select I2C
475 select DW_APB_TIMER
476 select APB_TIMER
477 select INTEL_SCU_IPC
478 select MFD_INTEL_MSIC
479 ---help---
480 Select to build a kernel capable of supporting Intel MID (Mobile
481 Internet Device) platform systems which do not have the PCI legacy
482 interfaces. If you are building for a PC class system say N here.
484 Intel MID platforms are based on an Intel processor and chipset which
485 consume less power than most of the x86 derivatives.
487 config X86_INTEL_LPSS
488 bool "Intel Low Power Subsystem Support"
489 depends on ACPI
490 select COMMON_CLK
491 select PINCTRL
492 ---help---
493 Select to build support for Intel Low Power Subsystem such as
494 found on Intel Lynxpoint PCH. Selecting this option enables
495 things like clock tree (common clock framework) and pincontrol
496 which are needed by the LPSS peripheral drivers.
498 config IOSF_MBI
499 tristate "Intel SoC IOSF Sideband support for SoC platforms"
500 depends on PCI
501 ---help---
502 This option enables sideband register access support for Intel SoC
503 platforms. On these platforms the IOSF sideband is used in lieu of
504 MSR's for some register accesses, mostly but not limited to thermal
505 and power. Drivers may query the availability of this device to
506 determine if they need the sideband in order to work on these
507 platforms. The sideband is available on the following SoC products.
508 This list is not meant to be exclusive.
509 - BayTrail
510 - Braswell
511 - Quark
513 You should say Y if you are running a kernel on one of these SoC's.
515 config IOSF_MBI_DEBUG
516 bool "Enable IOSF sideband access through debugfs"
517 depends on IOSF_MBI && DEBUG_FS
518 ---help---
519 Select this option to expose the IOSF sideband access registers (MCR,
520 MDR, MCRX) through debugfs to write and read register information from
521 different units on the SoC. This is most useful for obtaining device
522 state information for debug and analysis. As this is a general access
523 mechanism, users of this option would have specific knowledge of the
524 device they want to access.
526 If you don't require the option or are in doubt, say N.
528 config X86_RDC321X
529 bool "RDC R-321x SoC"
530 depends on X86_32
531 depends on X86_EXTENDED_PLATFORM
532 select M486
533 select X86_REBOOTFIXUPS
534 ---help---
535 This option is needed for RDC R-321x system-on-chip, also known
536 as R-8610-(G).
537 If you don't have one of these chips, you should say N here.
539 config X86_32_NON_STANDARD
540 bool "Support non-standard 32-bit SMP architectures"
541 depends on X86_32 && SMP
542 depends on X86_EXTENDED_PLATFORM
543 ---help---
544 This option compiles in the bigsmp and STA2X11 default
545 subarchitectures. It is intended for a generic binary
546 kernel. If you select them all, kernel will probe it one by
547 one and will fallback to default.
549 # Alphabetically sorted list of Non standard 32 bit platforms
551 config X86_SUPPORTS_MEMORY_FAILURE
552 def_bool y
553 # MCE code calls memory_failure():
554 depends on X86_MCE
555 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
556 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
557 depends on X86_64 || !SPARSEMEM
558 select ARCH_SUPPORTS_MEMORY_FAILURE
560 config STA2X11
561 bool "STA2X11 Companion Chip Support"
562 depends on X86_32_NON_STANDARD && PCI
563 select X86_DEV_DMA_OPS
564 select X86_DMA_REMAP
565 select SWIOTLB
566 select MFD_STA2X11
567 select ARCH_REQUIRE_GPIOLIB
568 default n
569 ---help---
570 This adds support for boards based on the STA2X11 IO-Hub,
571 a.k.a. "ConneXt". The chip is used in place of the standard
572 PC chipset, so all "standard" peripherals are missing. If this
573 option is selected the kernel will still be able to boot on
574 standard PC machines.
576 config X86_32_IRIS
577 tristate "Eurobraille/Iris poweroff module"
578 depends on X86_32
579 ---help---
580 The Iris machines from EuroBraille do not have APM or ACPI support
581 to shut themselves down properly. A special I/O sequence is
582 needed to do so, which is what this module does at
583 kernel shutdown.
585 This is only for Iris machines from EuroBraille.
587 If unused, say N.
589 config SCHED_OMIT_FRAME_POINTER
590 def_bool y
591 prompt "Single-depth WCHAN output"
592 depends on X86
593 ---help---
594 Calculate simpler /proc/<PID>/wchan values. If this option
595 is disabled then wchan values will recurse back to the
596 caller function. This provides more accurate wchan values,
597 at the expense of slightly more scheduling overhead.
599 If in doubt, say "Y".
601 menuconfig HYPERVISOR_GUEST
602 bool "Linux guest support"
603 ---help---
604 Say Y here to enable options for running Linux under various hyper-
605 visors. This option enables basic hypervisor detection and platform
606 setup.
608 If you say N, all options in this submenu will be skipped and
609 disabled, and Linux guest support won't be built in.
611 if HYPERVISOR_GUEST
613 config PARAVIRT
614 bool "Enable paravirtualization code"
615 ---help---
616 This changes the kernel so it can modify itself when it is run
617 under a hypervisor, potentially improving performance significantly
618 over full virtualization. However, when run without a hypervisor
619 the kernel is theoretically slower and slightly larger.
621 config PARAVIRT_DEBUG
622 bool "paravirt-ops debugging"
623 depends on PARAVIRT && DEBUG_KERNEL
624 ---help---
625 Enable to debug paravirt_ops internals. Specifically, BUG if
626 a paravirt_op is missing when it is called.
628 config PARAVIRT_SPINLOCKS
629 bool "Paravirtualization layer for spinlocks"
630 depends on PARAVIRT && SMP
631 select UNINLINE_SPIN_UNLOCK
632 ---help---
633 Paravirtualized spinlocks allow a pvops backend to replace the
634 spinlock implementation with something virtualization-friendly
635 (for example, block the virtual CPU rather than spinning).
637 It has a minimal impact on native kernels and gives a nice performance
638 benefit on paravirtualized KVM / Xen kernels.
640 If you are unsure how to answer this question, answer Y.
642 source "arch/x86/xen/Kconfig"
644 config KVM_GUEST
645 bool "KVM Guest support (including kvmclock)"
646 depends on PARAVIRT
647 select PARAVIRT_CLOCK
648 default y
649 ---help---
650 This option enables various optimizations for running under the KVM
651 hypervisor. It includes a paravirtualized clock, so that instead
652 of relying on a PIT (or probably other) emulation by the
653 underlying device model, the host provides the guest with
654 timing infrastructure such as time of day, and system time
656 config KVM_DEBUG_FS
657 bool "Enable debug information for KVM Guests in debugfs"
658 depends on KVM_GUEST && DEBUG_FS
659 default n
660 ---help---
661 This option enables collection of various statistics for KVM guest.
662 Statistics are displayed in debugfs filesystem. Enabling this option
663 may incur significant overhead.
665 source "arch/x86/lguest/Kconfig"
667 config PARAVIRT_TIME_ACCOUNTING
668 bool "Paravirtual steal time accounting"
669 depends on PARAVIRT
670 default n
671 ---help---
672 Select this option to enable fine granularity task steal time
673 accounting. Time spent executing other tasks in parallel with
674 the current vCPU is discounted from the vCPU power. To account for
675 that, there can be a small performance impact.
677 If in doubt, say N here.
679 config PARAVIRT_CLOCK
680 bool
682 endif #HYPERVISOR_GUEST
684 config NO_BOOTMEM
685 def_bool y
687 config MEMTEST
688 bool "Memtest"
689 ---help---
690 This option adds a kernel parameter 'memtest', which allows memtest
691 to be set.
692 memtest=0, mean disabled; -- default
693 memtest=1, mean do 1 test pattern;
694 ...
695 memtest=4, mean do 4 test patterns.
696 If you are unsure how to answer this question, answer N.
698 source "arch/x86/Kconfig.cpu"
700 config HPET_TIMER
701 def_bool X86_64
702 prompt "HPET Timer Support" if X86_32
703 ---help---
704 Use the IA-PC HPET (High Precision Event Timer) to manage
705 time in preference to the PIT and RTC, if a HPET is
706 present.
707 HPET is the next generation timer replacing legacy 8254s.
708 The HPET provides a stable time base on SMP
709 systems, unlike the TSC, but it is more expensive to access,
710 as it is off-chip. You can find the HPET spec at
711 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
713 You can safely choose Y here. However, HPET will only be
714 activated if the platform and the BIOS support this feature.
715 Otherwise the 8254 will be used for timing services.
717 Choose N to continue using the legacy 8254 timer.
719 config HPET_EMULATE_RTC
720 def_bool y
721 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
723 config APB_TIMER
724 def_bool y if X86_INTEL_MID
725 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
726 select DW_APB_TIMER
727 depends on X86_INTEL_MID && SFI
728 help
729 APB timer is the replacement for 8254, HPET on X86 MID platforms.
730 The APBT provides a stable time base on SMP
731 systems, unlike the TSC, but it is more expensive to access,
732 as it is off-chip. APB timers are always running regardless of CPU
733 C states, they are used as per CPU clockevent device when possible.
735 # Mark as expert because too many people got it wrong.
736 # The code disables itself when not needed.
737 config DMI
738 default y
739 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
740 bool "Enable DMI scanning" if EXPERT
741 ---help---
742 Enabled scanning of DMI to identify machine quirks. Say Y
743 here unless you have verified that your setup is not
744 affected by entries in the DMI blacklist. Required by PNP
745 BIOS code.
747 config GART_IOMMU
748 bool "Old AMD GART IOMMU support"
749 select SWIOTLB
750 depends on X86_64 && PCI && AMD_NB
751 ---help---
752 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
753 GART based hardware IOMMUs.
755 The GART supports full DMA access for devices with 32-bit access
756 limitations, on systems with more than 3 GB. This is usually needed
757 for USB, sound, many IDE/SATA chipsets and some other devices.
759 Newer systems typically have a modern AMD IOMMU, supported via
760 the CONFIG_AMD_IOMMU=y config option.
762 In normal configurations this driver is only active when needed:
763 there's more than 3 GB of memory and the system contains a
764 32-bit limited device.
766 If unsure, say Y.
768 config CALGARY_IOMMU
769 bool "IBM Calgary IOMMU support"
770 select SWIOTLB
771 depends on X86_64 && PCI
772 ---help---
773 Support for hardware IOMMUs in IBM's xSeries x366 and x460
774 systems. Needed to run systems with more than 3GB of memory
775 properly with 32-bit PCI devices that do not support DAC
776 (Double Address Cycle). Calgary also supports bus level
777 isolation, where all DMAs pass through the IOMMU. This
778 prevents them from going anywhere except their intended
779 destination. This catches hard-to-find kernel bugs and
780 mis-behaving drivers and devices that do not use the DMA-API
781 properly to set up their DMA buffers. The IOMMU can be
782 turned off at boot time with the iommu=off parameter.
783 Normally the kernel will make the right choice by itself.
784 If unsure, say Y.
786 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
787 def_bool y
788 prompt "Should Calgary be enabled by default?"
789 depends on CALGARY_IOMMU
790 ---help---
791 Should Calgary be enabled by default? if you choose 'y', Calgary
792 will be used (if it exists). If you choose 'n', Calgary will not be
793 used even if it exists. If you choose 'n' and would like to use
794 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
795 If unsure, say Y.
797 # need this always selected by IOMMU for the VIA workaround
798 config SWIOTLB
799 def_bool y if X86_64
800 ---help---
801 Support for software bounce buffers used on x86-64 systems
802 which don't have a hardware IOMMU. Using this PCI devices
803 which can only access 32-bits of memory can be used on systems
804 with more than 3 GB of memory.
805 If unsure, say Y.
807 config IOMMU_HELPER
808 def_bool y
809 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
811 config MAXSMP
812 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
813 depends on X86_64 && SMP && DEBUG_KERNEL
814 select CPUMASK_OFFSTACK
815 ---help---
816 Enable maximum number of CPUS and NUMA Nodes for this architecture.
817 If unsure, say N.
819 config NR_CPUS
820 int "Maximum number of CPUs" if SMP && !MAXSMP
821 range 2 8 if SMP && X86_32 && !X86_BIGSMP
822 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
823 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
824 default "1" if !SMP
825 default "8192" if MAXSMP
826 default "32" if SMP && X86_BIGSMP
827 default "8" if SMP
828 ---help---
829 This allows you to specify the maximum number of CPUs which this
830 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
831 supported value is 4096, otherwise the maximum value is 512. The
832 minimum value which makes sense is 2.
834 This is purely to save memory - each supported CPU adds
835 approximately eight kilobytes to the kernel image.
837 config SCHED_SMT
838 bool "SMT (Hyperthreading) scheduler support"
839 depends on X86_HT
840 ---help---
841 SMT scheduler support improves the CPU scheduler's decision making
842 when dealing with Intel Pentium 4 chips with HyperThreading at a
843 cost of slightly increased overhead in some places. If unsure say
844 N here.
846 config SCHED_MC
847 def_bool y
848 prompt "Multi-core scheduler support"
849 depends on X86_HT
850 ---help---
851 Multi-core scheduler support improves the CPU scheduler's decision
852 making when dealing with multi-core CPU chips at a cost of slightly
853 increased overhead in some places. If unsure say N here.
855 source "kernel/Kconfig.preempt"
857 config X86_UP_APIC
858 bool "Local APIC support on uniprocessors"
859 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
860 ---help---
861 A local APIC (Advanced Programmable Interrupt Controller) is an
862 integrated interrupt controller in the CPU. If you have a single-CPU
863 system which has a processor with a local APIC, you can say Y here to
864 enable and use it. If you say Y here even though your machine doesn't
865 have a local APIC, then the kernel will still run with no slowdown at
866 all. The local APIC supports CPU-generated self-interrupts (timer,
867 performance counters), and the NMI watchdog which detects hard
868 lockups.
870 config X86_UP_APIC_MSI
871 def_bool y
872 select X86_UP_APIC if X86_32 && !SMP && !X86_32_NON_STANDARD && PCI_MSI
874 config X86_UP_IOAPIC
875 bool "IO-APIC support on uniprocessors"
876 depends on X86_UP_APIC
877 ---help---
878 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
879 SMP-capable replacement for PC-style interrupt controllers. Most
880 SMP systems and many recent uniprocessor systems have one.
882 If you have a single-CPU system with an IO-APIC, you can say Y here
883 to use it. If you say Y here even though your machine doesn't have
884 an IO-APIC, then the kernel will still run with no slowdown at all.
886 config X86_LOCAL_APIC
887 def_bool y
888 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
890 config X86_IO_APIC
891 def_bool y
892 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC || PCI_MSI
893 select GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
894 select IRQ_DOMAIN
896 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
897 bool "Reroute for broken boot IRQs"
898 depends on X86_IO_APIC
899 ---help---
900 This option enables a workaround that fixes a source of
901 spurious interrupts. This is recommended when threaded
902 interrupt handling is used on systems where the generation of
903 superfluous "boot interrupts" cannot be disabled.
905 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
906 entry in the chipset's IO-APIC is masked (as, e.g. the RT
907 kernel does during interrupt handling). On chipsets where this
908 boot IRQ generation cannot be disabled, this workaround keeps
909 the original IRQ line masked so that only the equivalent "boot
910 IRQ" is delivered to the CPUs. The workaround also tells the
911 kernel to set up the IRQ handler on the boot IRQ line. In this
912 way only one interrupt is delivered to the kernel. Otherwise
913 the spurious second interrupt may cause the kernel to bring
914 down (vital) interrupt lines.
916 Only affects "broken" chipsets. Interrupt sharing may be
917 increased on these systems.
919 config X86_MCE
920 bool "Machine Check / overheating reporting"
921 default y
922 ---help---
923 Machine Check support allows the processor to notify the
924 kernel if it detects a problem (e.g. overheating, data corruption).
925 The action the kernel takes depends on the severity of the problem,
926 ranging from warning messages to halting the machine.
928 config X86_MCE_INTEL
929 def_bool y
930 prompt "Intel MCE features"
931 depends on X86_MCE && X86_LOCAL_APIC
932 ---help---
933 Additional support for intel specific MCE features such as
934 the thermal monitor.
936 config X86_MCE_AMD
937 def_bool y
938 prompt "AMD MCE features"
939 depends on X86_MCE && X86_LOCAL_APIC
940 ---help---
941 Additional support for AMD specific MCE features such as
942 the DRAM Error Threshold.
944 config X86_ANCIENT_MCE
945 bool "Support for old Pentium 5 / WinChip machine checks"
946 depends on X86_32 && X86_MCE
947 ---help---
948 Include support for machine check handling on old Pentium 5 or WinChip
949 systems. These typically need to be enabled explicitly on the command
950 line.
952 config X86_MCE_THRESHOLD
953 depends on X86_MCE_AMD || X86_MCE_INTEL
954 def_bool y
956 config X86_MCE_INJECT
957 depends on X86_MCE
958 tristate "Machine check injector support"
959 ---help---
960 Provide support for injecting machine checks for testing purposes.
961 If you don't know what a machine check is and you don't do kernel
962 QA it is safe to say n.
964 config X86_THERMAL_VECTOR
965 def_bool y
966 depends on X86_MCE_INTEL
968 config VM86
969 bool "Enable VM86 support" if EXPERT
970 default y
971 depends on X86_32
972 ---help---
973 This option is required by programs like DOSEMU to run
974 16-bit real mode legacy code on x86 processors. It also may
975 be needed by software like XFree86 to initialize some video
976 cards via BIOS. Disabling this option saves about 6K.
978 config X86_16BIT
979 bool "Enable support for 16-bit segments" if EXPERT
980 default y
981 ---help---
982 This option is required by programs like Wine to run 16-bit
983 protected mode legacy code on x86 processors. Disabling
984 this option saves about 300 bytes on i386, or around 6K text
985 plus 16K runtime memory on x86-64,
987 config X86_ESPFIX32
988 def_bool y
989 depends on X86_16BIT && X86_32
991 config X86_ESPFIX64
992 def_bool y
993 depends on X86_16BIT && X86_64
995 config TOSHIBA
996 tristate "Toshiba Laptop support"
997 depends on X86_32
998 ---help---
999 This adds a driver to safely access the System Management Mode of
1000 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1001 not work on models with a Phoenix BIOS. The System Management Mode
1002 is used to set the BIOS and power saving options on Toshiba portables.
1004 For information on utilities to make use of this driver see the
1005 Toshiba Linux utilities web site at:
1006 <http://www.buzzard.org.uk/toshiba/>.
1008 Say Y if you intend to run this kernel on a Toshiba portable.
1009 Say N otherwise.
1011 config I8K
1012 tristate "Dell laptop support"
1013 select HWMON
1014 ---help---
1015 This adds a driver to safely access the System Management Mode
1016 of the CPU on the Dell Inspiron 8000. The System Management Mode
1017 is used to read cpu temperature and cooling fan status and to
1018 control the fans on the I8K portables.
1020 This driver has been tested only on the Inspiron 8000 but it may
1021 also work with other Dell laptops. You can force loading on other
1022 models by passing the parameter `force=1' to the module. Use at
1023 your own risk.
1025 For information on utilities to make use of this driver see the
1026 I8K Linux utilities web site at:
1027 <http://people.debian.org/~dz/i8k/>
1029 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1030 Say N otherwise.
1032 config X86_REBOOTFIXUPS
1033 bool "Enable X86 board specific fixups for reboot"
1034 depends on X86_32
1035 ---help---
1036 This enables chipset and/or board specific fixups to be done
1037 in order to get reboot to work correctly. This is only needed on
1038 some combinations of hardware and BIOS. The symptom, for which
1039 this config is intended, is when reboot ends with a stalled/hung
1040 system.
1042 Currently, the only fixup is for the Geode machines using
1043 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1045 Say Y if you want to enable the fixup. Currently, it's safe to
1046 enable this option even if you don't need it.
1047 Say N otherwise.
1049 config MICROCODE
1050 tristate "CPU microcode loading support"
1051 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1052 select FW_LOADER
1053 ---help---
1055 If you say Y here, you will be able to update the microcode on
1056 certain Intel and AMD processors. The Intel support is for the
1057 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1058 Xeon etc. The AMD support is for families 0x10 and later. You will
1059 obviously need the actual microcode binary data itself which is not
1060 shipped with the Linux kernel.
1062 This option selects the general module only, you need to select
1063 at least one vendor specific module as well.
1065 To compile this driver as a module, choose M here: the module
1066 will be called microcode.
1068 config MICROCODE_INTEL
1069 bool "Intel microcode loading support"
1070 depends on MICROCODE
1071 default MICROCODE
1072 select FW_LOADER
1073 ---help---
1074 This options enables microcode patch loading support for Intel
1075 processors.
1077 For the current Intel microcode data package go to
1078 <https://downloadcenter.intel.com> and search for
1079 'Linux Processor Microcode Data File'.
1081 config MICROCODE_AMD
1082 bool "AMD microcode loading support"
1083 depends on MICROCODE
1084 select FW_LOADER
1085 ---help---
1086 If you select this option, microcode patch loading support for AMD
1087 processors will be enabled.
1089 config MICROCODE_OLD_INTERFACE
1090 def_bool y
1091 depends on MICROCODE
1093 config MICROCODE_INTEL_EARLY
1094 def_bool n
1096 config MICROCODE_AMD_EARLY
1097 def_bool n
1099 config MICROCODE_EARLY
1100 bool "Early load microcode"
1101 depends on MICROCODE=y && BLK_DEV_INITRD
1102 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1103 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1104 default y
1105 help
1106 This option provides functionality to read additional microcode data
1107 at the beginning of initrd image. The data tells kernel to load
1108 microcode to CPU's as early as possible. No functional change if no
1109 microcode data is glued to the initrd, therefore it's safe to say Y.
1111 config X86_MSR
1112 tristate "/dev/cpu/*/msr - Model-specific register support"
1113 ---help---
1114 This device gives privileged processes access to the x86
1115 Model-Specific Registers (MSRs). It is a character device with
1116 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1117 MSR accesses are directed to a specific CPU on multi-processor
1118 systems.
1120 config X86_CPUID
1121 tristate "/dev/cpu/*/cpuid - CPU information support"
1122 ---help---
1123 This device gives processes access to the x86 CPUID instruction to
1124 be executed on a specific processor. It is a character device
1125 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1126 /dev/cpu/31/cpuid.
1128 choice
1129 prompt "High Memory Support"
1130 default HIGHMEM4G
1131 depends on X86_32
1133 config NOHIGHMEM
1134 bool "off"
1135 ---help---
1136 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1137 However, the address space of 32-bit x86 processors is only 4
1138 Gigabytes large. That means that, if you have a large amount of
1139 physical memory, not all of it can be "permanently mapped" by the
1140 kernel. The physical memory that's not permanently mapped is called
1141 "high memory".
1143 If you are compiling a kernel which will never run on a machine with
1144 more than 1 Gigabyte total physical RAM, answer "off" here (default
1145 choice and suitable for most users). This will result in a "3GB/1GB"
1146 split: 3GB are mapped so that each process sees a 3GB virtual memory
1147 space and the remaining part of the 4GB virtual memory space is used
1148 by the kernel to permanently map as much physical memory as
1149 possible.
1151 If the machine has between 1 and 4 Gigabytes physical RAM, then
1152 answer "4GB" here.
1154 If more than 4 Gigabytes is used then answer "64GB" here. This
1155 selection turns Intel PAE (Physical Address Extension) mode on.
1156 PAE implements 3-level paging on IA32 processors. PAE is fully
1157 supported by Linux, PAE mode is implemented on all recent Intel
1158 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1159 then the kernel will not boot on CPUs that don't support PAE!
1161 The actual amount of total physical memory will either be
1162 auto detected or can be forced by using a kernel command line option
1163 such as "mem=256M". (Try "man bootparam" or see the documentation of
1164 your boot loader (lilo or loadlin) about how to pass options to the
1165 kernel at boot time.)
1167 If unsure, say "off".
1169 config HIGHMEM4G
1170 bool "4GB"
1171 ---help---
1172 Select this if you have a 32-bit processor and between 1 and 4
1173 gigabytes of physical RAM.
1175 config HIGHMEM64G
1176 bool "64GB"
1177 depends on !M486
1178 select X86_PAE
1179 ---help---
1180 Select this if you have a 32-bit processor and more than 4
1181 gigabytes of physical RAM.
1183 endchoice
1185 choice
1186 prompt "Memory split" if EXPERT
1187 default VMSPLIT_3G
1188 depends on X86_32
1189 ---help---
1190 Select the desired split between kernel and user memory.
1192 If the address range available to the kernel is less than the
1193 physical memory installed, the remaining memory will be available
1194 as "high memory". Accessing high memory is a little more costly
1195 than low memory, as it needs to be mapped into the kernel first.
1196 Note that increasing the kernel address space limits the range
1197 available to user programs, making the address space there
1198 tighter. Selecting anything other than the default 3G/1G split
1199 will also likely make your kernel incompatible with binary-only
1200 kernel modules.
1202 If you are not absolutely sure what you are doing, leave this
1203 option alone!
1205 config VMSPLIT_3G
1206 bool "3G/1G user/kernel split"
1207 config VMSPLIT_3G_OPT
1208 depends on !X86_PAE
1209 bool "3G/1G user/kernel split (for full 1G low memory)"
1210 config VMSPLIT_2G
1211 bool "2G/2G user/kernel split"
1212 config VMSPLIT_2G_OPT
1213 depends on !X86_PAE
1214 bool "2G/2G user/kernel split (for full 2G low memory)"
1215 config VMSPLIT_1G
1216 bool "1G/3G user/kernel split"
1217 endchoice
1219 config PAGE_OFFSET
1220 hex
1221 default 0xB0000000 if VMSPLIT_3G_OPT
1222 default 0x80000000 if VMSPLIT_2G
1223 default 0x78000000 if VMSPLIT_2G_OPT
1224 default 0x40000000 if VMSPLIT_1G
1225 default 0xC0000000
1226 depends on X86_32
1228 config HIGHMEM
1229 def_bool y
1230 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1232 config X86_PAE
1233 bool "PAE (Physical Address Extension) Support"
1234 depends on X86_32 && !HIGHMEM4G
1235 ---help---
1236 PAE is required for NX support, and furthermore enables
1237 larger swapspace support for non-overcommit purposes. It
1238 has the cost of more pagetable lookup overhead, and also
1239 consumes more pagetable space per process.
1241 config ARCH_PHYS_ADDR_T_64BIT
1242 def_bool y
1243 depends on X86_64 || X86_PAE
1245 config ARCH_DMA_ADDR_T_64BIT
1246 def_bool y
1247 depends on X86_64 || HIGHMEM64G
1249 config DIRECT_GBPAGES
1250 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1251 default y
1252 depends on X86_64
1253 ---help---
1254 Allow the kernel linear mapping to use 1GB pages on CPUs that
1255 support it. This can improve the kernel's performance a tiny bit by
1256 reducing TLB pressure. If in doubt, say "Y".
1258 # Common NUMA Features
1259 config NUMA
1260 bool "Numa Memory Allocation and Scheduler Support"
1261 depends on SMP
1262 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1263 default y if X86_BIGSMP
1264 ---help---
1265 Enable NUMA (Non Uniform Memory Access) support.
1267 The kernel will try to allocate memory used by a CPU on the
1268 local memory controller of the CPU and add some more
1269 NUMA awareness to the kernel.
1271 For 64-bit this is recommended if the system is Intel Core i7
1272 (or later), AMD Opteron, or EM64T NUMA.
1274 For 32-bit this is only needed if you boot a 32-bit
1275 kernel on a 64-bit NUMA platform.
1277 Otherwise, you should say N.
1279 config AMD_NUMA
1280 def_bool y
1281 prompt "Old style AMD Opteron NUMA detection"
1282 depends on X86_64 && NUMA && PCI
1283 ---help---
1284 Enable AMD NUMA node topology detection. You should say Y here if
1285 you have a multi processor AMD system. This uses an old method to
1286 read the NUMA configuration directly from the builtin Northbridge
1287 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1288 which also takes priority if both are compiled in.
1290 config X86_64_ACPI_NUMA
1291 def_bool y
1292 prompt "ACPI NUMA detection"
1293 depends on X86_64 && NUMA && ACPI && PCI
1294 select ACPI_NUMA
1295 ---help---
1296 Enable ACPI SRAT based node topology detection.
1298 # Some NUMA nodes have memory ranges that span
1299 # other nodes. Even though a pfn is valid and
1300 # between a node's start and end pfns, it may not
1301 # reside on that node. See memmap_init_zone()
1302 # for details.
1303 config NODES_SPAN_OTHER_NODES
1304 def_bool y
1305 depends on X86_64_ACPI_NUMA
1307 config NUMA_EMU
1308 bool "NUMA emulation"
1309 depends on NUMA
1310 ---help---
1311 Enable NUMA emulation. A flat machine will be split
1312 into virtual nodes when booted with "numa=fake=N", where N is the
1313 number of nodes. This is only useful for debugging.
1315 config NODES_SHIFT
1316 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1317 range 1 10
1318 default "10" if MAXSMP
1319 default "6" if X86_64
1320 default "3"
1321 depends on NEED_MULTIPLE_NODES
1322 ---help---
1323 Specify the maximum number of NUMA Nodes available on the target
1324 system. Increases memory reserved to accommodate various tables.
1326 config ARCH_HAVE_MEMORY_PRESENT
1327 def_bool y
1328 depends on X86_32 && DISCONTIGMEM
1330 config NEED_NODE_MEMMAP_SIZE
1331 def_bool y
1332 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1334 config ARCH_FLATMEM_ENABLE
1335 def_bool y
1336 depends on X86_32 && !NUMA
1338 config ARCH_DISCONTIGMEM_ENABLE
1339 def_bool y
1340 depends on NUMA && X86_32
1342 config ARCH_DISCONTIGMEM_DEFAULT
1343 def_bool y
1344 depends on NUMA && X86_32
1346 config ARCH_SPARSEMEM_ENABLE
1347 def_bool y
1348 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1349 select SPARSEMEM_STATIC if X86_32
1350 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1352 config ARCH_SPARSEMEM_DEFAULT
1353 def_bool y
1354 depends on X86_64
1356 config ARCH_SELECT_MEMORY_MODEL
1357 def_bool y
1358 depends on ARCH_SPARSEMEM_ENABLE
1360 config ARCH_MEMORY_PROBE
1361 bool "Enable sysfs memory/probe interface"
1362 depends on X86_64 && MEMORY_HOTPLUG
1363 help
1364 This option enables a sysfs memory/probe interface for testing.
1365 See Documentation/memory-hotplug.txt for more information.
1366 If you are unsure how to answer this question, answer N.
1368 config ARCH_PROC_KCORE_TEXT
1369 def_bool y
1370 depends on X86_64 && PROC_KCORE
1372 config ILLEGAL_POINTER_VALUE
1373 hex
1374 default 0 if X86_32
1375 default 0xdead000000000000 if X86_64
1377 source "mm/Kconfig"
1379 config HIGHPTE
1380 bool "Allocate 3rd-level pagetables from highmem"
1381 depends on HIGHMEM
1382 ---help---
1383 The VM uses one page table entry for each page of physical memory.
1384 For systems with a lot of RAM, this can be wasteful of precious
1385 low memory. Setting this option will put user-space page table
1386 entries in high memory.
1388 config X86_CHECK_BIOS_CORRUPTION
1389 bool "Check for low memory corruption"
1390 ---help---
1391 Periodically check for memory corruption in low memory, which
1392 is suspected to be caused by BIOS. Even when enabled in the
1393 configuration, it is disabled at runtime. Enable it by
1394 setting "memory_corruption_check=1" on the kernel command
1395 line. By default it scans the low 64k of memory every 60
1396 seconds; see the memory_corruption_check_size and
1397 memory_corruption_check_period parameters in
1398 Documentation/kernel-parameters.txt to adjust this.
1400 When enabled with the default parameters, this option has
1401 almost no overhead, as it reserves a relatively small amount
1402 of memory and scans it infrequently. It both detects corruption
1403 and prevents it from affecting the running system.
1405 It is, however, intended as a diagnostic tool; if repeatable
1406 BIOS-originated corruption always affects the same memory,
1407 you can use memmap= to prevent the kernel from using that
1408 memory.
1410 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1411 bool "Set the default setting of memory_corruption_check"
1412 depends on X86_CHECK_BIOS_CORRUPTION
1413 default y
1414 ---help---
1415 Set whether the default state of memory_corruption_check is
1416 on or off.
1418 config X86_RESERVE_LOW
1419 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1420 default 64
1421 range 4 640
1422 ---help---
1423 Specify the amount of low memory to reserve for the BIOS.
1425 The first page contains BIOS data structures that the kernel
1426 must not use, so that page must always be reserved.
1428 By default we reserve the first 64K of physical RAM, as a
1429 number of BIOSes are known to corrupt that memory range
1430 during events such as suspend/resume or monitor cable
1431 insertion, so it must not be used by the kernel.
1433 You can set this to 4 if you are absolutely sure that you
1434 trust the BIOS to get all its memory reservations and usages
1435 right. If you know your BIOS have problems beyond the
1436 default 64K area, you can set this to 640 to avoid using the
1437 entire low memory range.
1439 If you have doubts about the BIOS (e.g. suspend/resume does
1440 not work or there's kernel crashes after certain hardware
1441 hotplug events) then you might want to enable
1442 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1443 typical corruption patterns.
1445 Leave this to the default value of 64 if you are unsure.
1447 config MATH_EMULATION
1448 bool
1449 prompt "Math emulation" if X86_32
1450 ---help---
1451 Linux can emulate a math coprocessor (used for floating point
1452 operations) if you don't have one. 486DX and Pentium processors have
1453 a math coprocessor built in, 486SX and 386 do not, unless you added
1454 a 487DX or 387, respectively. (The messages during boot time can
1455 give you some hints here ["man dmesg"].) Everyone needs either a
1456 coprocessor or this emulation.
1458 If you don't have a math coprocessor, you need to say Y here; if you
1459 say Y here even though you have a coprocessor, the coprocessor will
1460 be used nevertheless. (This behavior can be changed with the kernel
1461 command line option "no387", which comes handy if your coprocessor
1462 is broken. Try "man bootparam" or see the documentation of your boot
1463 loader (lilo or loadlin) about how to pass options to the kernel at
1464 boot time.) This means that it is a good idea to say Y here if you
1465 intend to use this kernel on different machines.
1467 More information about the internals of the Linux math coprocessor
1468 emulation can be found in <file:arch/x86/math-emu/README>.
1470 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1471 kernel, it won't hurt.
1473 config MTRR
1474 def_bool y
1475 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1476 ---help---
1477 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1478 the Memory Type Range Registers (MTRRs) may be used to control
1479 processor access to memory ranges. This is most useful if you have
1480 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1481 allows bus write transfers to be combined into a larger transfer
1482 before bursting over the PCI/AGP bus. This can increase performance
1483 of image write operations 2.5 times or more. Saying Y here creates a
1484 /proc/mtrr file which may be used to manipulate your processor's
1485 MTRRs. Typically the X server should use this.
1487 This code has a reasonably generic interface so that similar
1488 control registers on other processors can be easily supported
1489 as well:
1491 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1492 Registers (ARRs) which provide a similar functionality to MTRRs. For
1493 these, the ARRs are used to emulate the MTRRs.
1494 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1495 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1496 write-combining. All of these processors are supported by this code
1497 and it makes sense to say Y here if you have one of them.
1499 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1500 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1501 can lead to all sorts of problems, so it's good to say Y here.
1503 You can safely say Y even if your machine doesn't have MTRRs, you'll
1504 just add about 9 KB to your kernel.
1506 See <file:Documentation/x86/mtrr.txt> for more information.
1508 config MTRR_SANITIZER
1509 def_bool y
1510 prompt "MTRR cleanup support"
1511 depends on MTRR
1512 ---help---
1513 Convert MTRR layout from continuous to discrete, so X drivers can
1514 add writeback entries.
1516 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1517 The largest mtrr entry size for a continuous block can be set with
1518 mtrr_chunk_size.
1520 If unsure, say Y.
1522 config MTRR_SANITIZER_ENABLE_DEFAULT
1523 int "MTRR cleanup enable value (0-1)"
1524 range 0 1
1525 default "0"
1526 depends on MTRR_SANITIZER
1527 ---help---
1528 Enable mtrr cleanup default value
1530 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1531 int "MTRR cleanup spare reg num (0-7)"
1532 range 0 7
1533 default "1"
1534 depends on MTRR_SANITIZER
1535 ---help---
1536 mtrr cleanup spare entries default, it can be changed via
1537 mtrr_spare_reg_nr=N on the kernel command line.
1539 config X86_PAT
1540 def_bool y
1541 prompt "x86 PAT support" if EXPERT
1542 depends on MTRR
1543 ---help---
1544 Use PAT attributes to setup page level cache control.
1546 PATs are the modern equivalents of MTRRs and are much more
1547 flexible than MTRRs.
1549 Say N here if you see bootup problems (boot crash, boot hang,
1550 spontaneous reboots) or a non-working video driver.
1552 If unsure, say Y.
1554 config ARCH_USES_PG_UNCACHED
1555 def_bool y
1556 depends on X86_PAT
1558 config ARCH_RANDOM
1559 def_bool y
1560 prompt "x86 architectural random number generator" if EXPERT
1561 ---help---
1562 Enable the x86 architectural RDRAND instruction
1563 (Intel Bull Mountain technology) to generate random numbers.
1564 If supported, this is a high bandwidth, cryptographically
1565 secure hardware random number generator.
1567 config X86_SMAP
1568 def_bool y
1569 prompt "Supervisor Mode Access Prevention" if EXPERT
1570 ---help---
1571 Supervisor Mode Access Prevention (SMAP) is a security
1572 feature in newer Intel processors. There is a small
1573 performance cost if this enabled and turned on; there is
1574 also a small increase in the kernel size if this is enabled.
1576 If unsure, say Y.
1578 config EFI
1579 bool "EFI runtime service support"
1580 depends on ACPI
1581 select UCS2_STRING
1582 select EFI_RUNTIME_WRAPPERS
1583 ---help---
1584 This enables the kernel to use EFI runtime services that are
1585 available (such as the EFI variable services).
1587 This option is only useful on systems that have EFI firmware.
1588 In addition, you should use the latest ELILO loader available
1589 at <http://elilo.sourceforge.net> in order to take advantage
1590 of EFI runtime services. However, even with this option, the
1591 resultant kernel should continue to boot on existing non-EFI
1592 platforms.
1594 config EFI_STUB
1595 bool "EFI stub support"
1596 depends on EFI && !X86_USE_3DNOW
1597 select RELOCATABLE
1598 ---help---
1599 This kernel feature allows a bzImage to be loaded directly
1600 by EFI firmware without the use of a bootloader.
1602 See Documentation/efi-stub.txt for more information.
1604 config EFI_MIXED
1605 bool "EFI mixed-mode support"
1606 depends on EFI_STUB && X86_64
1607 ---help---
1608 Enabling this feature allows a 64-bit kernel to be booted
1609 on a 32-bit firmware, provided that your CPU supports 64-bit
1610 mode.
1612 Note that it is not possible to boot a mixed-mode enabled
1613 kernel via the EFI boot stub - a bootloader that supports
1614 the EFI handover protocol must be used.
1616 If unsure, say N.
1618 config SECCOMP
1619 def_bool y
1620 prompt "Enable seccomp to safely compute untrusted bytecode"
1621 ---help---
1622 This kernel feature is useful for number crunching applications
1623 that may need to compute untrusted bytecode during their
1624 execution. By using pipes or other transports made available to
1625 the process as file descriptors supporting the read/write
1626 syscalls, it's possible to isolate those applications in
1627 their own address space using seccomp. Once seccomp is
1628 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1629 and the task is only allowed to execute a few safe syscalls
1630 defined by each seccomp mode.
1632 If unsure, say Y. Only embedded should say N here.
1634 source kernel/Kconfig.hz
1636 config KEXEC
1637 bool "kexec system call"
1638 ---help---
1639 kexec is a system call that implements the ability to shutdown your
1640 current kernel, and to start another kernel. It is like a reboot
1641 but it is independent of the system firmware. And like a reboot
1642 you can start any kernel with it, not just Linux.
1644 The name comes from the similarity to the exec system call.
1646 It is an ongoing process to be certain the hardware in a machine
1647 is properly shutdown, so do not be surprised if this code does not
1648 initially work for you. As of this writing the exact hardware
1649 interface is strongly in flux, so no good recommendation can be
1650 made.
1652 config KEXEC_FILE
1653 bool "kexec file based system call"
1654 select BUILD_BIN2C
1655 depends on KEXEC
1656 depends on X86_64
1657 depends on CRYPTO=y
1658 depends on CRYPTO_SHA256=y
1659 ---help---
1660 This is new version of kexec system call. This system call is
1661 file based and takes file descriptors as system call argument
1662 for kernel and initramfs as opposed to list of segments as
1663 accepted by previous system call.
1665 config KEXEC_VERIFY_SIG
1666 bool "Verify kernel signature during kexec_file_load() syscall"
1667 depends on KEXEC_FILE
1668 ---help---
1669 This option makes kernel signature verification mandatory for
1670 kexec_file_load() syscall. If kernel is signature can not be
1671 verified, kexec_file_load() will fail.
1673 This option enforces signature verification at generic level.
1674 One needs to enable signature verification for type of kernel
1675 image being loaded to make sure it works. For example, enable
1676 bzImage signature verification option to be able to load and
1677 verify signatures of bzImage. Otherwise kernel loading will fail.
1679 config KEXEC_BZIMAGE_VERIFY_SIG
1680 bool "Enable bzImage signature verification support"
1681 depends on KEXEC_VERIFY_SIG
1682 depends on SIGNED_PE_FILE_VERIFICATION
1683 select SYSTEM_TRUSTED_KEYRING
1684 ---help---
1685 Enable bzImage signature verification support.
1687 config CRASH_DUMP
1688 bool "kernel crash dumps"
1689 depends on X86_64 || (X86_32 && HIGHMEM)
1690 ---help---
1691 Generate crash dump after being started by kexec.
1692 This should be normally only set in special crash dump kernels
1693 which are loaded in the main kernel with kexec-tools into
1694 a specially reserved region and then later executed after
1695 a crash by kdump/kexec. The crash dump kernel must be compiled
1696 to a memory address not used by the main kernel or BIOS using
1697 PHYSICAL_START, or it must be built as a relocatable image
1698 (CONFIG_RELOCATABLE=y).
1699 For more details see Documentation/kdump/kdump.txt
1701 config KEXEC_JUMP
1702 bool "kexec jump"
1703 depends on KEXEC && HIBERNATION
1704 ---help---
1705 Jump between original kernel and kexeced kernel and invoke
1706 code in physical address mode via KEXEC
1708 config PHYSICAL_START
1709 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1710 default "0x1000000"
1711 ---help---
1712 This gives the physical address where the kernel is loaded.
1714 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1715 bzImage will decompress itself to above physical address and
1716 run from there. Otherwise, bzImage will run from the address where
1717 it has been loaded by the boot loader and will ignore above physical
1718 address.
1720 In normal kdump cases one does not have to set/change this option
1721 as now bzImage can be compiled as a completely relocatable image
1722 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1723 address. This option is mainly useful for the folks who don't want
1724 to use a bzImage for capturing the crash dump and want to use a
1725 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1726 to be specifically compiled to run from a specific memory area
1727 (normally a reserved region) and this option comes handy.
1729 So if you are using bzImage for capturing the crash dump,
1730 leave the value here unchanged to 0x1000000 and set
1731 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1732 for capturing the crash dump change this value to start of
1733 the reserved region. In other words, it can be set based on
1734 the "X" value as specified in the "crashkernel=YM@XM"
1735 command line boot parameter passed to the panic-ed
1736 kernel. Please take a look at Documentation/kdump/kdump.txt
1737 for more details about crash dumps.
1739 Usage of bzImage for capturing the crash dump is recommended as
1740 one does not have to build two kernels. Same kernel can be used
1741 as production kernel and capture kernel. Above option should have
1742 gone away after relocatable bzImage support is introduced. But it
1743 is present because there are users out there who continue to use
1744 vmlinux for dump capture. This option should go away down the
1745 line.
1747 Don't change this unless you know what you are doing.
1749 config RELOCATABLE
1750 bool "Build a relocatable kernel"
1751 default y
1752 ---help---
1753 This builds a kernel image that retains relocation information
1754 so it can be loaded someplace besides the default 1MB.
1755 The relocations tend to make the kernel binary about 10% larger,
1756 but are discarded at runtime.
1758 One use is for the kexec on panic case where the recovery kernel
1759 must live at a different physical address than the primary
1760 kernel.
1762 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1763 it has been loaded at and the compile time physical address
1764 (CONFIG_PHYSICAL_START) is used as the minimum location.
1766 config RANDOMIZE_BASE
1767 bool "Randomize the address of the kernel image"
1768 depends on RELOCATABLE
1769 default n
1770 ---help---
1771 Randomizes the physical and virtual address at which the
1772 kernel image is decompressed, as a security feature that
1773 deters exploit attempts relying on knowledge of the location
1774 of kernel internals.
1776 Entropy is generated using the RDRAND instruction if it is
1777 supported. If RDTSC is supported, it is used as well. If
1778 neither RDRAND nor RDTSC are supported, then randomness is
1779 read from the i8254 timer.
1781 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1782 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1783 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1784 minimum of 2MiB, only 10 bits of entropy is theoretically
1785 possible. At best, due to page table layouts, 64-bit can use
1786 9 bits of entropy and 32-bit uses 8 bits.
1788 If unsure, say N.
1790 config RANDOMIZE_BASE_MAX_OFFSET
1791 hex "Maximum kASLR offset allowed" if EXPERT
1792 depends on RANDOMIZE_BASE
1793 range 0x0 0x20000000 if X86_32
1794 default "0x20000000" if X86_32
1795 range 0x0 0x40000000 if X86_64
1796 default "0x40000000" if X86_64
1797 ---help---
1798 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1799 memory is used to determine the maximal offset in bytes that will
1800 be applied to the kernel when kernel Address Space Layout
1801 Randomization (kASLR) is active. This must be a multiple of
1802 PHYSICAL_ALIGN.
1804 On 32-bit this is limited to 512MiB by page table layouts. The
1805 default is 512MiB.
1807 On 64-bit this is limited by how the kernel fixmap page table is
1808 positioned, so this cannot be larger than 1GiB currently. Without
1809 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1810 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1811 modules area will shrink to compensate, up to the current maximum
1812 1GiB to 1GiB split. The default is 1GiB.
1814 If unsure, leave at the default value.
1816 # Relocation on x86 needs some additional build support
1817 config X86_NEED_RELOCS
1818 def_bool y
1819 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1821 config PHYSICAL_ALIGN
1822 hex "Alignment value to which kernel should be aligned"
1823 default "0x200000"
1824 range 0x2000 0x1000000 if X86_32
1825 range 0x200000 0x1000000 if X86_64
1826 ---help---
1827 This value puts the alignment restrictions on physical address
1828 where kernel is loaded and run from. Kernel is compiled for an
1829 address which meets above alignment restriction.
1831 If bootloader loads the kernel at a non-aligned address and
1832 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1833 address aligned to above value and run from there.
1835 If bootloader loads the kernel at a non-aligned address and
1836 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1837 load address and decompress itself to the address it has been
1838 compiled for and run from there. The address for which kernel is
1839 compiled already meets above alignment restrictions. Hence the
1840 end result is that kernel runs from a physical address meeting
1841 above alignment restrictions.
1843 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1844 this value must be a multiple of 0x200000.
1846 Don't change this unless you know what you are doing.
1848 config HOTPLUG_CPU
1849 bool "Support for hot-pluggable CPUs"
1850 depends on SMP
1851 ---help---
1852 Say Y here to allow turning CPUs off and on. CPUs can be
1853 controlled through /sys/devices/system/cpu.
1854 ( Note: power management support will enable this option
1855 automatically on SMP systems. )
1856 Say N if you want to disable CPU hotplug.
1858 config BOOTPARAM_HOTPLUG_CPU0
1859 bool "Set default setting of cpu0_hotpluggable"
1860 default n
1861 depends on HOTPLUG_CPU
1862 ---help---
1863 Set whether default state of cpu0_hotpluggable is on or off.
1865 Say Y here to enable CPU0 hotplug by default. If this switch
1866 is turned on, there is no need to give cpu0_hotplug kernel
1867 parameter and the CPU0 hotplug feature is enabled by default.
1869 Please note: there are two known CPU0 dependencies if you want
1870 to enable the CPU0 hotplug feature either by this switch or by
1871 cpu0_hotplug kernel parameter.
1873 First, resume from hibernate or suspend always starts from CPU0.
1874 So hibernate and suspend are prevented if CPU0 is offline.
1876 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1877 offline if any interrupt can not migrate out of CPU0. There may
1878 be other CPU0 dependencies.
1880 Please make sure the dependencies are under your control before
1881 you enable this feature.
1883 Say N if you don't want to enable CPU0 hotplug feature by default.
1884 You still can enable the CPU0 hotplug feature at boot by kernel
1885 parameter cpu0_hotplug.
1887 config DEBUG_HOTPLUG_CPU0
1888 def_bool n
1889 prompt "Debug CPU0 hotplug"
1890 depends on HOTPLUG_CPU
1891 ---help---
1892 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1893 soon as possible and boots up userspace with CPU0 offlined. User
1894 can online CPU0 back after boot time.
1896 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1897 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1898 compilation or giving cpu0_hotplug kernel parameter at boot.
1900 If unsure, say N.
1902 config COMPAT_VDSO
1903 def_bool n
1904 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
1905 depends on X86_32 || IA32_EMULATION
1906 ---help---
1907 Certain buggy versions of glibc will crash if they are
1908 presented with a 32-bit vDSO that is not mapped at the address
1909 indicated in its segment table.
1911 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
1912 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
1913 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
1914 the only released version with the bug, but OpenSUSE 9
1915 contains a buggy "glibc 2.3.2".
1917 The symptom of the bug is that everything crashes on startup, saying:
1918 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
1920 Saying Y here changes the default value of the vdso32 boot
1921 option from 1 to 0, which turns off the 32-bit vDSO entirely.
1922 This works around the glibc bug but hurts performance.
1924 If unsure, say N: if you are compiling your own kernel, you
1925 are unlikely to be using a buggy version of glibc.
1927 config CMDLINE_BOOL
1928 bool "Built-in kernel command line"
1929 ---help---
1930 Allow for specifying boot arguments to the kernel at
1931 build time. On some systems (e.g. embedded ones), it is
1932 necessary or convenient to provide some or all of the
1933 kernel boot arguments with the kernel itself (that is,
1934 to not rely on the boot loader to provide them.)
1936 To compile command line arguments into the kernel,
1937 set this option to 'Y', then fill in the
1938 the boot arguments in CONFIG_CMDLINE.
1940 Systems with fully functional boot loaders (i.e. non-embedded)
1941 should leave this option set to 'N'.
1943 config CMDLINE
1944 string "Built-in kernel command string"
1945 depends on CMDLINE_BOOL
1946 default ""
1947 ---help---
1948 Enter arguments here that should be compiled into the kernel
1949 image and used at boot time. If the boot loader provides a
1950 command line at boot time, it is appended to this string to
1951 form the full kernel command line, when the system boots.
1953 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1954 change this behavior.
1956 In most cases, the command line (whether built-in or provided
1957 by the boot loader) should specify the device for the root
1958 file system.
1960 config CMDLINE_OVERRIDE
1961 bool "Built-in command line overrides boot loader arguments"
1962 depends on CMDLINE_BOOL
1963 ---help---
1964 Set this option to 'Y' to have the kernel ignore the boot loader
1965 command line, and use ONLY the built-in command line.
1967 This is used to work around broken boot loaders. This should
1968 be set to 'N' under normal conditions.
1970 endmenu
1972 config ARCH_ENABLE_MEMORY_HOTPLUG
1973 def_bool y
1974 depends on X86_64 || (X86_32 && HIGHMEM)
1976 config ARCH_ENABLE_MEMORY_HOTREMOVE
1977 def_bool y
1978 depends on MEMORY_HOTPLUG
1980 config USE_PERCPU_NUMA_NODE_ID
1981 def_bool y
1982 depends on NUMA
1984 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1985 def_bool y
1986 depends on X86_64 || X86_PAE
1988 config ARCH_ENABLE_HUGEPAGE_MIGRATION
1989 def_bool y
1990 depends on X86_64 && HUGETLB_PAGE && MIGRATION
1992 menu "Power management and ACPI options"
1994 config ARCH_HIBERNATION_HEADER
1995 def_bool y
1996 depends on X86_64 && HIBERNATION
1998 source "kernel/power/Kconfig"
2000 source "drivers/acpi/Kconfig"
2002 source "drivers/sfi/Kconfig"
2004 config X86_APM_BOOT
2005 def_bool y
2006 depends on APM
2008 menuconfig APM
2009 tristate "APM (Advanced Power Management) BIOS support"
2010 depends on X86_32 && PM_SLEEP
2011 ---help---
2012 APM is a BIOS specification for saving power using several different
2013 techniques. This is mostly useful for battery powered laptops with
2014 APM compliant BIOSes. If you say Y here, the system time will be
2015 reset after a RESUME operation, the /proc/apm device will provide
2016 battery status information, and user-space programs will receive
2017 notification of APM "events" (e.g. battery status change).
2019 If you select "Y" here, you can disable actual use of the APM
2020 BIOS by passing the "apm=off" option to the kernel at boot time.
2022 Note that the APM support is almost completely disabled for
2023 machines with more than one CPU.
2025 In order to use APM, you will need supporting software. For location
2026 and more information, read <file:Documentation/power/apm-acpi.txt>
2027 and the Battery Powered Linux mini-HOWTO, available from
2028 <http://www.tldp.org/docs.html#howto>.
2030 This driver does not spin down disk drives (see the hdparm(8)
2031 manpage ("man 8 hdparm") for that), and it doesn't turn off
2032 VESA-compliant "green" monitors.
2034 This driver does not support the TI 4000M TravelMate and the ACER
2035 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2036 desktop machines also don't have compliant BIOSes, and this driver
2037 may cause those machines to panic during the boot phase.
2039 Generally, if you don't have a battery in your machine, there isn't
2040 much point in using this driver and you should say N. If you get
2041 random kernel OOPSes or reboots that don't seem to be related to
2042 anything, try disabling/enabling this option (or disabling/enabling
2043 APM in your BIOS).
2045 Some other things you should try when experiencing seemingly random,
2046 "weird" problems:
2048 1) make sure that you have enough swap space and that it is
2049 enabled.
2050 2) pass the "no-hlt" option to the kernel
2051 3) switch on floating point emulation in the kernel and pass
2052 the "no387" option to the kernel
2053 4) pass the "floppy=nodma" option to the kernel
2054 5) pass the "mem=4M" option to the kernel (thereby disabling
2055 all but the first 4 MB of RAM)
2056 6) make sure that the CPU is not over clocked.
2057 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2058 8) disable the cache from your BIOS settings
2059 9) install a fan for the video card or exchange video RAM
2060 10) install a better fan for the CPU
2061 11) exchange RAM chips
2062 12) exchange the motherboard.
2064 To compile this driver as a module, choose M here: the
2065 module will be called apm.
2067 if APM
2069 config APM_IGNORE_USER_SUSPEND
2070 bool "Ignore USER SUSPEND"
2071 ---help---
2072 This option will ignore USER SUSPEND requests. On machines with a
2073 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2074 series notebooks, it is necessary to say Y because of a BIOS bug.
2076 config APM_DO_ENABLE
2077 bool "Enable PM at boot time"
2078 ---help---
2079 Enable APM features at boot time. From page 36 of the APM BIOS
2080 specification: "When disabled, the APM BIOS does not automatically
2081 power manage devices, enter the Standby State, enter the Suspend
2082 State, or take power saving steps in response to CPU Idle calls."
2083 This driver will make CPU Idle calls when Linux is idle (unless this
2084 feature is turned off -- see "Do CPU IDLE calls", below). This
2085 should always save battery power, but more complicated APM features
2086 will be dependent on your BIOS implementation. You may need to turn
2087 this option off if your computer hangs at boot time when using APM
2088 support, or if it beeps continuously instead of suspending. Turn
2089 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2090 T400CDT. This is off by default since most machines do fine without
2091 this feature.
2093 config APM_CPU_IDLE
2094 depends on CPU_IDLE
2095 bool "Make CPU Idle calls when idle"
2096 ---help---
2097 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2098 On some machines, this can activate improved power savings, such as
2099 a slowed CPU clock rate, when the machine is idle. These idle calls
2100 are made after the idle loop has run for some length of time (e.g.,
2101 333 mS). On some machines, this will cause a hang at boot time or
2102 whenever the CPU becomes idle. (On machines with more than one CPU,
2103 this option does nothing.)
2105 config APM_DISPLAY_BLANK
2106 bool "Enable console blanking using APM"
2107 ---help---
2108 Enable console blanking using the APM. Some laptops can use this to
2109 turn off the LCD backlight when the screen blanker of the Linux
2110 virtual console blanks the screen. Note that this is only used by
2111 the virtual console screen blanker, and won't turn off the backlight
2112 when using the X Window system. This also doesn't have anything to
2113 do with your VESA-compliant power-saving monitor. Further, this
2114 option doesn't work for all laptops -- it might not turn off your
2115 backlight at all, or it might print a lot of errors to the console,
2116 especially if you are using gpm.
2118 config APM_ALLOW_INTS
2119 bool "Allow interrupts during APM BIOS calls"
2120 ---help---
2121 Normally we disable external interrupts while we are making calls to
2122 the APM BIOS as a measure to lessen the effects of a badly behaving
2123 BIOS implementation. The BIOS should reenable interrupts if it
2124 needs to. Unfortunately, some BIOSes do not -- especially those in
2125 many of the newer IBM Thinkpads. If you experience hangs when you
2126 suspend, try setting this to Y. Otherwise, say N.
2128 endif # APM
2130 source "drivers/cpufreq/Kconfig"
2132 source "drivers/cpuidle/Kconfig"
2134 source "drivers/idle/Kconfig"
2136 endmenu
2139 menu "Bus options (PCI etc.)"
2141 config PCI
2142 bool "PCI support"
2143 default y
2144 ---help---
2145 Find out whether you have a PCI motherboard. PCI is the name of a
2146 bus system, i.e. the way the CPU talks to the other stuff inside
2147 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2148 VESA. If you have PCI, say Y, otherwise N.
2150 choice
2151 prompt "PCI access mode"
2152 depends on X86_32 && PCI
2153 default PCI_GOANY
2154 ---help---
2155 On PCI systems, the BIOS can be used to detect the PCI devices and
2156 determine their configuration. However, some old PCI motherboards
2157 have BIOS bugs and may crash if this is done. Also, some embedded
2158 PCI-based systems don't have any BIOS at all. Linux can also try to
2159 detect the PCI hardware directly without using the BIOS.
2161 With this option, you can specify how Linux should detect the
2162 PCI devices. If you choose "BIOS", the BIOS will be used,
2163 if you choose "Direct", the BIOS won't be used, and if you
2164 choose "MMConfig", then PCI Express MMCONFIG will be used.
2165 If you choose "Any", the kernel will try MMCONFIG, then the
2166 direct access method and falls back to the BIOS if that doesn't
2167 work. If unsure, go with the default, which is "Any".
2169 config PCI_GOBIOS
2170 bool "BIOS"
2172 config PCI_GOMMCONFIG
2173 bool "MMConfig"
2175 config PCI_GODIRECT
2176 bool "Direct"
2178 config PCI_GOOLPC
2179 bool "OLPC XO-1"
2180 depends on OLPC
2182 config PCI_GOANY
2183 bool "Any"
2185 endchoice
2187 config PCI_BIOS
2188 def_bool y
2189 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2191 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2192 config PCI_DIRECT
2193 def_bool y
2194 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2196 config PCI_MMCONFIG
2197 def_bool y
2198 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2200 config PCI_OLPC
2201 def_bool y
2202 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2204 config PCI_XEN
2205 def_bool y
2206 depends on PCI && XEN
2207 select SWIOTLB_XEN
2209 config PCI_DOMAINS
2210 def_bool y
2211 depends on PCI
2213 config PCI_MMCONFIG
2214 bool "Support mmconfig PCI config space access"
2215 depends on X86_64 && PCI && ACPI
2217 config PCI_CNB20LE_QUIRK
2218 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2219 depends on PCI
2220 help
2221 Read the PCI windows out of the CNB20LE host bridge. This allows
2222 PCI hotplug to work on systems with the CNB20LE chipset which do
2223 not have ACPI.
2225 There's no public spec for this chipset, and this functionality
2226 is known to be incomplete.
2228 You should say N unless you know you need this.
2230 source "drivers/pci/pcie/Kconfig"
2232 source "drivers/pci/Kconfig"
2234 # x86_64 have no ISA slots, but can have ISA-style DMA.
2235 config ISA_DMA_API
2236 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2237 default y
2238 help
2239 Enables ISA-style DMA support for devices requiring such controllers.
2240 If unsure, say Y.
2242 if X86_32
2244 config ISA
2245 bool "ISA support"
2246 ---help---
2247 Find out whether you have ISA slots on your motherboard. ISA is the
2248 name of a bus system, i.e. the way the CPU talks to the other stuff
2249 inside your box. Other bus systems are PCI, EISA, MicroChannel
2250 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2251 newer boards don't support it. If you have ISA, say Y, otherwise N.
2253 config EISA
2254 bool "EISA support"
2255 depends on ISA
2256 ---help---
2257 The Extended Industry Standard Architecture (EISA) bus was
2258 developed as an open alternative to the IBM MicroChannel bus.
2260 The EISA bus provided some of the features of the IBM MicroChannel
2261 bus while maintaining backward compatibility with cards made for
2262 the older ISA bus. The EISA bus saw limited use between 1988 and
2263 1995 when it was made obsolete by the PCI bus.
2265 Say Y here if you are building a kernel for an EISA-based machine.
2267 Otherwise, say N.
2269 source "drivers/eisa/Kconfig"
2271 config SCx200
2272 tristate "NatSemi SCx200 support"
2273 ---help---
2274 This provides basic support for National Semiconductor's
2275 (now AMD's) Geode processors. The driver probes for the
2276 PCI-IDs of several on-chip devices, so its a good dependency
2277 for other scx200_* drivers.
2279 If compiled as a module, the driver is named scx200.
2281 config SCx200HR_TIMER
2282 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2283 depends on SCx200
2284 default y
2285 ---help---
2286 This driver provides a clocksource built upon the on-chip
2287 27MHz high-resolution timer. Its also a workaround for
2288 NSC Geode SC-1100's buggy TSC, which loses time when the
2289 processor goes idle (as is done by the scheduler). The
2290 other workaround is idle=poll boot option.
2292 config OLPC
2293 bool "One Laptop Per Child support"
2294 depends on !X86_PAE
2295 select GPIOLIB
2296 select OF
2297 select OF_PROMTREE
2298 select IRQ_DOMAIN
2299 ---help---
2300 Add support for detecting the unique features of the OLPC
2301 XO hardware.
2303 config OLPC_XO1_PM
2304 bool "OLPC XO-1 Power Management"
2305 depends on OLPC && MFD_CS5535 && PM_SLEEP
2306 select MFD_CORE
2307 ---help---
2308 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2310 config OLPC_XO1_RTC
2311 bool "OLPC XO-1 Real Time Clock"
2312 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2313 ---help---
2314 Add support for the XO-1 real time clock, which can be used as a
2315 programmable wakeup source.
2317 config OLPC_XO1_SCI
2318 bool "OLPC XO-1 SCI extras"
2319 depends on OLPC && OLPC_XO1_PM
2320 depends on INPUT=y
2321 select POWER_SUPPLY
2322 select GPIO_CS5535
2323 select MFD_CORE
2324 ---help---
2325 Add support for SCI-based features of the OLPC XO-1 laptop:
2326 - EC-driven system wakeups
2327 - Power button
2328 - Ebook switch
2329 - Lid switch
2330 - AC adapter status updates
2331 - Battery status updates
2333 config OLPC_XO15_SCI
2334 bool "OLPC XO-1.5 SCI extras"
2335 depends on OLPC && ACPI
2336 select POWER_SUPPLY
2337 ---help---
2338 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2339 - EC-driven system wakeups
2340 - AC adapter status updates
2341 - Battery status updates
2343 config ALIX
2344 bool "PCEngines ALIX System Support (LED setup)"
2345 select GPIOLIB
2346 ---help---
2347 This option enables system support for the PCEngines ALIX.
2348 At present this just sets up LEDs for GPIO control on
2349 ALIX2/3/6 boards. However, other system specific setup should
2350 get added here.
2352 Note: You must still enable the drivers for GPIO and LED support
2353 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2355 Note: You have to set alix.force=1 for boards with Award BIOS.
2357 config NET5501
2358 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2359 select GPIOLIB
2360 ---help---
2361 This option enables system support for the Soekris Engineering net5501.
2363 config GEOS
2364 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2365 select GPIOLIB
2366 depends on DMI
2367 ---help---
2368 This option enables system support for the Traverse Technologies GEOS.
2370 config TS5500
2371 bool "Technologic Systems TS-5500 platform support"
2372 depends on MELAN
2373 select CHECK_SIGNATURE
2374 select NEW_LEDS
2375 select LEDS_CLASS
2376 ---help---
2377 This option enables system support for the Technologic Systems TS-5500.
2379 endif # X86_32
2381 config AMD_NB
2382 def_bool y
2383 depends on CPU_SUP_AMD && PCI
2385 source "drivers/pcmcia/Kconfig"
2387 source "drivers/pci/hotplug/Kconfig"
2389 config RAPIDIO
2390 tristate "RapidIO support"
2391 depends on PCI
2392 default n
2393 help
2394 If enabled this option will include drivers and the core
2395 infrastructure code to support RapidIO interconnect devices.
2397 source "drivers/rapidio/Kconfig"
2399 config X86_SYSFB
2400 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2401 help
2402 Firmwares often provide initial graphics framebuffers so the BIOS,
2403 bootloader or kernel can show basic video-output during boot for
2404 user-guidance and debugging. Historically, x86 used the VESA BIOS
2405 Extensions and EFI-framebuffers for this, which are mostly limited
2406 to x86.
2407 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2408 framebuffers so the new generic system-framebuffer drivers can be
2409 used on x86. If the framebuffer is not compatible with the generic
2410 modes, it is adverticed as fallback platform framebuffer so legacy
2411 drivers like efifb, vesafb and uvesafb can pick it up.
2412 If this option is not selected, all system framebuffers are always
2413 marked as fallback platform framebuffers as usual.
2415 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2416 not be able to pick up generic system framebuffers if this option
2417 is selected. You are highly encouraged to enable simplefb as
2418 replacement if you select this option. simplefb can correctly deal
2419 with generic system framebuffers. But you should still keep vesafb
2420 and others enabled as fallback if a system framebuffer is
2421 incompatible with simplefb.
2423 If unsure, say Y.
2425 endmenu
2428 menu "Executable file formats / Emulations"
2430 source "fs/Kconfig.binfmt"
2432 config IA32_EMULATION
2433 bool "IA32 Emulation"
2434 depends on X86_64
2435 select BINFMT_ELF
2436 select COMPAT_BINFMT_ELF
2437 select HAVE_UID16
2438 ---help---
2439 Include code to run legacy 32-bit programs under a
2440 64-bit kernel. You should likely turn this on, unless you're
2441 100% sure that you don't have any 32-bit programs left.
2443 config IA32_AOUT
2444 tristate "IA32 a.out support"
2445 depends on IA32_EMULATION
2446 ---help---
2447 Support old a.out binaries in the 32bit emulation.
2449 config X86_X32
2450 bool "x32 ABI for 64-bit mode"
2451 depends on X86_64 && IA32_EMULATION
2452 ---help---
2453 Include code to run binaries for the x32 native 32-bit ABI
2454 for 64-bit processors. An x32 process gets access to the
2455 full 64-bit register file and wide data path while leaving
2456 pointers at 32 bits for smaller memory footprint.
2458 You will need a recent binutils (2.22 or later) with
2459 elf32_x86_64 support enabled to compile a kernel with this
2460 option set.
2462 config COMPAT
2463 def_bool y
2464 depends on IA32_EMULATION || X86_X32
2465 select ARCH_WANT_OLD_COMPAT_IPC
2467 if COMPAT
2468 config COMPAT_FOR_U64_ALIGNMENT
2469 def_bool y
2471 config SYSVIPC_COMPAT
2472 def_bool y
2473 depends on SYSVIPC
2474 endif
2476 endmenu
2479 config HAVE_ATOMIC_IOMAP
2480 def_bool y
2481 depends on X86_32
2483 config X86_DEV_DMA_OPS
2484 bool
2485 depends on X86_64 || STA2X11
2487 config X86_DMA_REMAP
2488 bool
2489 depends on STA2X11
2491 config PMC_ATOM
2492 def_bool y
2493 depends on PCI
2495 source "net/Kconfig"
2497 source "drivers/Kconfig"
2499 source "drivers/firmware/Kconfig"
2501 source "fs/Kconfig"
2503 source "arch/x86/Kconfig.debug"
2505 source "security/Kconfig"
2507 source "crypto/Kconfig"
2509 source "arch/x86/kvm/Kconfig"
2511 source "lib/Kconfig"