Version:  2.0.40 2.2.26 2.4.37 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17

Linux/arch/x86/Kconfig

  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
  8 
  9 config X86_32
 10         def_bool y
 11         depends on !64BIT
 12         select CLKSRC_I8253
 13         select HAVE_UID16
 14 
 15 config X86_64
 16         def_bool y
 17         depends on 64BIT
 18         select X86_DEV_DMA_OPS
 19         select ARCH_USE_CMPXCHG_LOCKREF
 20 
 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 ARCH_WANTS_PROT_NUMA_PROT_NONE
 34         select HAVE_IDE
 35         select HAVE_OPROFILE
 36         select HAVE_PCSPKR_PLATFORM
 37         select HAVE_PERF_EVENTS
 38         select HAVE_IOREMAP_PROT
 39         select HAVE_KPROBES
 40         select HAVE_MEMBLOCK
 41         select HAVE_MEMBLOCK_NODE_MAP
 42         select ARCH_DISCARD_MEMBLOCK
 43         select ARCH_WANT_OPTIONAL_GPIOLIB
 44         select ARCH_WANT_FRAME_POINTERS
 45         select HAVE_DMA_ATTRS
 46         select HAVE_DMA_CONTIGUOUS
 47         select HAVE_KRETPROBES
 48         select GENERIC_EARLY_IOREMAP
 49         select HAVE_OPTPROBES
 50         select HAVE_KPROBES_ON_FTRACE
 51         select HAVE_FTRACE_MCOUNT_RECORD
 52         select HAVE_FENTRY if X86_64
 53         select HAVE_C_RECORDMCOUNT
 54         select HAVE_DYNAMIC_FTRACE
 55         select HAVE_DYNAMIC_FTRACE_WITH_REGS
 56         select HAVE_FUNCTION_TRACER
 57         select HAVE_FUNCTION_GRAPH_TRACER
 58         select HAVE_FUNCTION_GRAPH_FP_TEST
 59         select HAVE_SYSCALL_TRACEPOINTS
 60         select SYSCTL_EXCEPTION_TRACE
 61         select HAVE_KVM
 62         select HAVE_ARCH_KGDB
 63         select HAVE_ARCH_TRACEHOOK
 64         select HAVE_GENERIC_DMA_COHERENT if X86_32
 65         select HAVE_EFFICIENT_UNALIGNED_ACCESS
 66         select USER_STACKTRACE_SUPPORT
 67         select HAVE_REGS_AND_STACK_ACCESS_API
 68         select HAVE_DMA_API_DEBUG
 69         select HAVE_KERNEL_GZIP
 70         select HAVE_KERNEL_BZIP2
 71         select HAVE_KERNEL_LZMA
 72         select HAVE_KERNEL_XZ
 73         select HAVE_KERNEL_LZO
 74         select HAVE_KERNEL_LZ4
 75         select HAVE_HW_BREAKPOINT
 76         select HAVE_MIXED_BREAKPOINTS_REGS
 77         select PERF_EVENTS
 78         select HAVE_PERF_EVENTS_NMI
 79         select HAVE_PERF_REGS
 80         select HAVE_PERF_USER_STACK_DUMP
 81         select HAVE_DEBUG_KMEMLEAK
 82         select ANON_INODES
 83         select HAVE_ALIGNED_STRUCT_PAGE if SLUB
 84         select HAVE_CMPXCHG_LOCAL
 85         select HAVE_CMPXCHG_DOUBLE
 86         select HAVE_ARCH_KMEMCHECK
 87         select HAVE_USER_RETURN_NOTIFIER
 88         select ARCH_BINFMT_ELF_RANDOMIZE_PIE
 89         select HAVE_ARCH_JUMP_LABEL
 90         select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 91         select SPARSE_IRQ
 92         select GENERIC_FIND_FIRST_BIT
 93         select GENERIC_IRQ_PROBE
 94         select GENERIC_PENDING_IRQ if SMP
 95         select GENERIC_IRQ_SHOW
 96         select GENERIC_CLOCKEVENTS_MIN_ADJUST
 97         select IRQ_FORCED_THREADING
 98         select HAVE_BPF_JIT if X86_64
 99         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
100         select ARCH_HAS_SG_CHAIN
101         select CLKEVT_I8253
102         select ARCH_HAVE_NMI_SAFE_CMPXCHG
103         select GENERIC_IOMAP
104         select DCACHE_WORD_ACCESS
105         select GENERIC_SMP_IDLE_THREAD
106         select ARCH_WANT_IPC_PARSE_VERSION if X86_32
107         select HAVE_ARCH_SECCOMP_FILTER
108         select BUILDTIME_EXTABLE_SORT
109         select GENERIC_CMOS_UPDATE
110         select HAVE_ARCH_SOFT_DIRTY if X86_64
111         select CLOCKSOURCE_WATCHDOG
112         select GENERIC_CLOCKEVENTS
113         select ARCH_CLOCKSOURCE_DATA
114         select CLOCKSOURCE_VALIDATE_LAST_CYCLE
115         select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
116         select GENERIC_TIME_VSYSCALL
117         select GENERIC_STRNCPY_FROM_USER
118         select GENERIC_STRNLEN_USER
119         select HAVE_CONTEXT_TRACKING if X86_64
120         select HAVE_IRQ_TIME_ACCOUNTING
121         select VIRT_TO_BUS
122         select MODULES_USE_ELF_REL if X86_32
123         select MODULES_USE_ELF_RELA if X86_64
124         select CLONE_BACKWARDS if X86_32
125         select ARCH_USE_BUILTIN_BSWAP
126         select ARCH_USE_QUEUE_RWLOCK
127         select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
128         select OLD_SIGACTION if X86_32
129         select COMPAT_OLD_SIGACTION if IA32_EMULATION
130         select RTC_LIB
131         select HAVE_DEBUG_STACKOVERFLOW
132         select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
133         select HAVE_CC_STACKPROTECTOR
134         select GENERIC_CPU_AUTOPROBE
135         select HAVE_ARCH_AUDITSYSCALL
136         select ARCH_SUPPORTS_ATOMIC_RMW
137         select HAVE_ACPI_APEI if ACPI
138         select HAVE_ACPI_APEI_NMI if ACPI
139         select ACPI_LEGACY_TABLES_LOOKUP if ACPI
140 
141 config INSTRUCTION_DECODER
142         def_bool y
143         depends on KPROBES || PERF_EVENTS || UPROBES
144 
145 config OUTPUT_FORMAT
146         string
147         default "elf32-i386" if X86_32
148         default "elf64-x86-64" if X86_64
149 
150 config ARCH_DEFCONFIG
151         string
152         default "arch/x86/configs/i386_defconfig" if X86_32
153         default "arch/x86/configs/x86_64_defconfig" if X86_64
154 
155 config LOCKDEP_SUPPORT
156         def_bool y
157 
158 config STACKTRACE_SUPPORT
159         def_bool y
160 
161 config HAVE_LATENCYTOP_SUPPORT
162         def_bool y
163 
164 config MMU
165         def_bool y
166 
167 config SBUS
168         bool
169 
170 config NEED_DMA_MAP_STATE
171         def_bool y
172         depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
173 
174 config NEED_SG_DMA_LENGTH
175         def_bool y
176 
177 config GENERIC_ISA_DMA
178         def_bool y
179         depends on ISA_DMA_API
180 
181 config GENERIC_BUG
182         def_bool y
183         depends on BUG
184         select GENERIC_BUG_RELATIVE_POINTERS if X86_64
185 
186 config GENERIC_BUG_RELATIVE_POINTERS
187         bool
188 
189 config GENERIC_HWEIGHT
190         def_bool y
191 
192 config ARCH_MAY_HAVE_PC_FDC
193         def_bool y
194         depends on ISA_DMA_API
195 
196 config RWSEM_XCHGADD_ALGORITHM
197         def_bool y
198 
199 config GENERIC_CALIBRATE_DELAY
200         def_bool y
201 
202 config ARCH_HAS_CPU_RELAX
203         def_bool y
204 
205 config ARCH_HAS_CACHE_LINE_SIZE
206         def_bool y
207 
208 config HAVE_SETUP_PER_CPU_AREA
209         def_bool y
210 
211 config NEED_PER_CPU_EMBED_FIRST_CHUNK
212         def_bool y
213 
214 config NEED_PER_CPU_PAGE_FIRST_CHUNK
215         def_bool y
216 
217 config ARCH_HIBERNATION_POSSIBLE
218         def_bool y
219 
220 config ARCH_SUSPEND_POSSIBLE
221         def_bool y
222 
223 config ARCH_WANT_HUGE_PMD_SHARE
224         def_bool y
225 
226 config ARCH_WANT_GENERAL_HUGETLB
227         def_bool y
228 
229 config ZONE_DMA32
230         bool
231         default X86_64
232 
233 config AUDIT_ARCH
234         bool
235         default X86_64
236 
237 config ARCH_SUPPORTS_OPTIMIZED_INLINING
238         def_bool y
239 
240 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
241         def_bool y
242 
243 config HAVE_INTEL_TXT
244         def_bool y
245         depends on INTEL_IOMMU && ACPI
246 
247 config X86_32_SMP
248         def_bool y
249         depends on X86_32 && SMP
250 
251 config X86_64_SMP
252         def_bool y
253         depends on X86_64 && SMP
254 
255 config X86_HT
256         def_bool y
257         depends on SMP
258 
259 config X86_32_LAZY_GS
260         def_bool y
261         depends on X86_32 && !CC_STACKPROTECTOR
262 
263 config ARCH_HWEIGHT_CFLAGS
264         string
265         default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
266         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
267 
268 config ARCH_SUPPORTS_UPROBES
269         def_bool y
270 
271 config FIX_EARLYCON_MEM
272         def_bool y
273 
274 source "init/Kconfig"
275 source "kernel/Kconfig.freezer"
276 
277 menu "Processor type and features"
278 
279 config ZONE_DMA
280         bool "DMA memory allocation support" if EXPERT
281         default y
282         help
283           DMA memory allocation support allows devices with less than 32-bit
284           addressing to allocate within the first 16MB of address space.
285           Disable if no such devices will be used.
286 
287           If unsure, say Y.
288 
289 config SMP
290         bool "Symmetric multi-processing support"
291         ---help---
292           This enables support for systems with more than one CPU. If you have
293           a system with only one CPU, say N. If you have a system with more
294           than one CPU, say Y.
295 
296           If you say N here, the kernel will run on uni- and multiprocessor
297           machines, but will use only one CPU of a multiprocessor machine. If
298           you say Y here, the kernel will run on many, but not all,
299           uniprocessor machines. On a uniprocessor machine, the kernel
300           will run faster if you say N here.
301 
302           Note that if you say Y here and choose architecture "586" or
303           "Pentium" under "Processor family", the kernel will not work on 486
304           architectures. Similarly, multiprocessor kernels for the "PPro"
305           architecture may not work on all Pentium based boards.
306 
307           People using multiprocessor machines who say Y here should also say
308           Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
309           Management" code will be disabled if you say Y here.
310 
311           See also <file:Documentation/x86/i386/IO-APIC.txt>,
312           <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
313           <http://www.tldp.org/docs.html#howto>.
314 
315           If you don't know what to do here, say N.
316 
317 config X86_X2APIC
318         bool "Support x2apic"
319         depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
320         ---help---
321           This enables x2apic support on CPUs that have this feature.
322 
323           This allows 32-bit apic IDs (so it can support very large systems),
324           and accesses the local apic via MSRs not via mmio.
325 
326           If you don't know what to do here, say N.
327 
328 config X86_MPPARSE
329         bool "Enable MPS table" if ACPI || SFI
330         default y
331         depends on X86_LOCAL_APIC
332         ---help---
333           For old smp systems that do not have proper acpi support. Newer systems
334           (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
335 
336 config X86_BIGSMP
337         bool "Support for big SMP systems with more than 8 CPUs"
338         depends on X86_32 && SMP
339         ---help---
340           This option is needed for the systems that have more than 8 CPUs
341 
342 config GOLDFISH
343        def_bool y
344        depends on X86_GOLDFISH
345 
346 if X86_32
347 config X86_EXTENDED_PLATFORM
348         bool "Support for extended (non-PC) x86 platforms"
349         default y
350         ---help---
351           If you disable this option then the kernel will only support
352           standard PC platforms. (which covers the vast majority of
353           systems out there.)
354 
355           If you enable this option then you'll be able to select support
356           for the following (non-PC) 32 bit x86 platforms:
357                 Goldfish (Android emulator)
358                 AMD Elan
359                 RDC R-321x SoC
360                 SGI 320/540 (Visual Workstation)
361                 STA2X11-based (e.g. Northville)
362                 Moorestown MID devices
363 
364           If you have one of these systems, or if you want to build a
365           generic distribution kernel, say Y here - otherwise say N.
366 endif
367 
368 if X86_64
369 config X86_EXTENDED_PLATFORM
370         bool "Support for extended (non-PC) x86 platforms"
371         default y
372         ---help---
373           If you disable this option then the kernel will only support
374           standard PC platforms. (which covers the vast majority of
375           systems out there.)
376 
377           If you enable this option then you'll be able to select support
378           for the following (non-PC) 64 bit x86 platforms:
379                 Numascale NumaChip
380                 ScaleMP vSMP
381                 SGI Ultraviolet
382 
383           If you have one of these systems, or if you want to build a
384           generic distribution kernel, say Y here - otherwise say N.
385 endif
386 # This is an alphabetically sorted list of 64 bit extended platforms
387 # Please maintain the alphabetic order if and when there are additions
388 config X86_NUMACHIP
389         bool "Numascale NumaChip"
390         depends on X86_64
391         depends on X86_EXTENDED_PLATFORM
392         depends on NUMA
393         depends on SMP
394         depends on X86_X2APIC
395         depends on PCI_MMCONFIG
396         ---help---
397           Adds support for Numascale NumaChip large-SMP systems. Needed to
398           enable more than ~168 cores.
399           If you don't have one of these, you should say N here.
400 
401 config X86_VSMP
402         bool "ScaleMP vSMP"
403         select HYPERVISOR_GUEST
404         select PARAVIRT
405         depends on X86_64 && PCI
406         depends on X86_EXTENDED_PLATFORM
407         depends on SMP
408         ---help---
409           Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
410           supposed to run on these EM64T-based machines.  Only choose this option
411           if you have one of these machines.
412 
413 config X86_UV
414         bool "SGI Ultraviolet"
415         depends on X86_64
416         depends on X86_EXTENDED_PLATFORM
417         depends on NUMA
418         depends on X86_X2APIC
419         ---help---
420           This option is needed in order to support SGI Ultraviolet systems.
421           If you don't have one of these, you should say N here.
422 
423 # Following is an alphabetically sorted list of 32 bit extended platforms
424 # Please maintain the alphabetic order if and when there are additions
425 
426 config X86_GOLDFISH
427        bool "Goldfish (Virtual Platform)"
428        depends on X86_EXTENDED_PLATFORM
429        ---help---
430          Enable support for the Goldfish virtual platform used primarily
431          for Android development. Unless you are building for the Android
432          Goldfish emulator say N here.
433 
434 config X86_INTEL_CE
435         bool "CE4100 TV platform"
436         depends on PCI
437         depends on PCI_GODIRECT
438         depends on X86_IO_APIC
439         depends on X86_32
440         depends on X86_EXTENDED_PLATFORM
441         select X86_REBOOTFIXUPS
442         select OF
443         select OF_EARLY_FLATTREE
444         select IRQ_DOMAIN
445         ---help---
446           Select for the Intel CE media processor (CE4100) SOC.
447           This option compiles in support for the CE4100 SOC for settop
448           boxes and media devices.
449 
450 config X86_INTEL_MID
451         bool "Intel MID platform support"
452         depends on X86_32
453         depends on X86_EXTENDED_PLATFORM
454         depends on X86_PLATFORM_DEVICES
455         depends on PCI
456         depends on PCI_GOANY
457         depends on X86_IO_APIC
458         select SFI
459         select I2C
460         select DW_APB_TIMER
461         select APB_TIMER
462         select INTEL_SCU_IPC
463         select MFD_INTEL_MSIC
464         ---help---
465           Select to build a kernel capable of supporting Intel MID (Mobile
466           Internet Device) platform systems which do not have the PCI legacy
467           interfaces. If you are building for a PC class system say N here.
468 
469           Intel MID platforms are based on an Intel processor and chipset which
470           consume less power than most of the x86 derivatives.
471 
472 config X86_INTEL_LPSS
473         bool "Intel Low Power Subsystem Support"
474         depends on ACPI
475         select COMMON_CLK
476         select PINCTRL
477         ---help---
478           Select to build support for Intel Low Power Subsystem such as
479           found on Intel Lynxpoint PCH. Selecting this option enables
480           things like clock tree (common clock framework) and pincontrol
481           which are needed by the LPSS peripheral drivers.
482 
483 config X86_RDC321X
484         bool "RDC R-321x SoC"
485         depends on X86_32
486         depends on X86_EXTENDED_PLATFORM
487         select M486
488         select X86_REBOOTFIXUPS
489         ---help---
490           This option is needed for RDC R-321x system-on-chip, also known
491           as R-8610-(G).
492           If you don't have one of these chips, you should say N here.
493 
494 config X86_32_NON_STANDARD
495         bool "Support non-standard 32-bit SMP architectures"
496         depends on X86_32 && SMP
497         depends on X86_EXTENDED_PLATFORM
498         ---help---
499           This option compiles in the bigsmp and STA2X11 default
500           subarchitectures.  It is intended for a generic binary
501           kernel. If you select them all, kernel will probe it one by
502           one and will fallback to default.
503 
504 # Alphabetically sorted list of Non standard 32 bit platforms
505 
506 config X86_SUPPORTS_MEMORY_FAILURE
507         def_bool y
508         # MCE code calls memory_failure():
509         depends on X86_MCE
510         # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
511         # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
512         depends on X86_64 || !SPARSEMEM
513         select ARCH_SUPPORTS_MEMORY_FAILURE
514 
515 config STA2X11
516         bool "STA2X11 Companion Chip Support"
517         depends on X86_32_NON_STANDARD && PCI
518         select X86_DEV_DMA_OPS
519         select X86_DMA_REMAP
520         select SWIOTLB
521         select MFD_STA2X11
522         select ARCH_REQUIRE_GPIOLIB
523         default n
524         ---help---
525           This adds support for boards based on the STA2X11 IO-Hub,
526           a.k.a. "ConneXt". The chip is used in place of the standard
527           PC chipset, so all "standard" peripherals are missing. If this
528           option is selected the kernel will still be able to boot on
529           standard PC machines.
530 
531 config X86_32_IRIS
532         tristate "Eurobraille/Iris poweroff module"
533         depends on X86_32
534         ---help---
535           The Iris machines from EuroBraille do not have APM or ACPI support
536           to shut themselves down properly.  A special I/O sequence is
537           needed to do so, which is what this module does at
538           kernel shutdown.
539 
540           This is only for Iris machines from EuroBraille.
541 
542           If unused, say N.
543 
544 config SCHED_OMIT_FRAME_POINTER
545         def_bool y
546         prompt "Single-depth WCHAN output"
547         depends on X86
548         ---help---
549           Calculate simpler /proc/<PID>/wchan values. If this option
550           is disabled then wchan values will recurse back to the
551           caller function. This provides more accurate wchan values,
552           at the expense of slightly more scheduling overhead.
553 
554           If in doubt, say "Y".
555 
556 menuconfig HYPERVISOR_GUEST
557         bool "Linux guest support"
558         ---help---
559           Say Y here to enable options for running Linux under various hyper-
560           visors. This option enables basic hypervisor detection and platform
561           setup.
562 
563           If you say N, all options in this submenu will be skipped and
564           disabled, and Linux guest support won't be built in.
565 
566 if HYPERVISOR_GUEST
567 
568 config PARAVIRT
569         bool "Enable paravirtualization code"
570         ---help---
571           This changes the kernel so it can modify itself when it is run
572           under a hypervisor, potentially improving performance significantly
573           over full virtualization.  However, when run without a hypervisor
574           the kernel is theoretically slower and slightly larger.
575 
576 config PARAVIRT_DEBUG
577         bool "paravirt-ops debugging"
578         depends on PARAVIRT && DEBUG_KERNEL
579         ---help---
580           Enable to debug paravirt_ops internals.  Specifically, BUG if
581           a paravirt_op is missing when it is called.
582 
583 config PARAVIRT_SPINLOCKS
584         bool "Paravirtualization layer for spinlocks"
585         depends on PARAVIRT && SMP
586         select UNINLINE_SPIN_UNLOCK
587         ---help---
588           Paravirtualized spinlocks allow a pvops backend to replace the
589           spinlock implementation with something virtualization-friendly
590           (for example, block the virtual CPU rather than spinning).
591 
592           It has a minimal impact on native kernels and gives a nice performance
593           benefit on paravirtualized KVM / Xen kernels.
594 
595           If you are unsure how to answer this question, answer Y.
596 
597 source "arch/x86/xen/Kconfig"
598 
599 config KVM_GUEST
600         bool "KVM Guest support (including kvmclock)"
601         depends on PARAVIRT
602         select PARAVIRT_CLOCK
603         default y
604         ---help---
605           This option enables various optimizations for running under the KVM
606           hypervisor. It includes a paravirtualized clock, so that instead
607           of relying on a PIT (or probably other) emulation by the
608           underlying device model, the host provides the guest with
609           timing infrastructure such as time of day, and system time
610 
611 config KVM_DEBUG_FS
612         bool "Enable debug information for KVM Guests in debugfs"
613         depends on KVM_GUEST && DEBUG_FS
614         default n
615         ---help---
616           This option enables collection of various statistics for KVM guest.
617           Statistics are displayed in debugfs filesystem. Enabling this option
618           may incur significant overhead.
619 
620 source "arch/x86/lguest/Kconfig"
621 
622 config PARAVIRT_TIME_ACCOUNTING
623         bool "Paravirtual steal time accounting"
624         depends on PARAVIRT
625         default n
626         ---help---
627           Select this option to enable fine granularity task steal time
628           accounting. Time spent executing other tasks in parallel with
629           the current vCPU is discounted from the vCPU power. To account for
630           that, there can be a small performance impact.
631 
632           If in doubt, say N here.
633 
634 config PARAVIRT_CLOCK
635         bool
636 
637 endif #HYPERVISOR_GUEST
638 
639 config NO_BOOTMEM
640         def_bool y
641 
642 config MEMTEST
643         bool "Memtest"
644         ---help---
645           This option adds a kernel parameter 'memtest', which allows memtest
646           to be set.
647                 memtest=0, mean disabled; -- default
648                 memtest=1, mean do 1 test pattern;
649                 ...
650                 memtest=4, mean do 4 test patterns.
651           If you are unsure how to answer this question, answer N.
652 
653 source "arch/x86/Kconfig.cpu"
654 
655 config HPET_TIMER
656         def_bool X86_64
657         prompt "HPET Timer Support" if X86_32
658         ---help---
659           Use the IA-PC HPET (High Precision Event Timer) to manage
660           time in preference to the PIT and RTC, if a HPET is
661           present.
662           HPET is the next generation timer replacing legacy 8254s.
663           The HPET provides a stable time base on SMP
664           systems, unlike the TSC, but it is more expensive to access,
665           as it is off-chip.  You can find the HPET spec at
666           <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
667 
668           You can safely choose Y here.  However, HPET will only be
669           activated if the platform and the BIOS support this feature.
670           Otherwise the 8254 will be used for timing services.
671 
672           Choose N to continue using the legacy 8254 timer.
673 
674 config HPET_EMULATE_RTC
675         def_bool y
676         depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
677 
678 config APB_TIMER
679        def_bool y if X86_INTEL_MID
680        prompt "Intel MID APB Timer Support" if X86_INTEL_MID
681        select DW_APB_TIMER
682        depends on X86_INTEL_MID && SFI
683        help
684          APB timer is the replacement for 8254, HPET on X86 MID platforms.
685          The APBT provides a stable time base on SMP
686          systems, unlike the TSC, but it is more expensive to access,
687          as it is off-chip. APB timers are always running regardless of CPU
688          C states, they are used as per CPU clockevent device when possible.
689 
690 # Mark as expert because too many people got it wrong.
691 # The code disables itself when not needed.
692 config DMI
693         default y
694         select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
695         bool "Enable DMI scanning" if EXPERT
696         ---help---
697           Enabled scanning of DMI to identify machine quirks. Say Y
698           here unless you have verified that your setup is not
699           affected by entries in the DMI blacklist. Required by PNP
700           BIOS code.
701 
702 config GART_IOMMU
703         bool "Old AMD GART IOMMU support"
704         select SWIOTLB
705         depends on X86_64 && PCI && AMD_NB
706         ---help---
707           Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
708           GART based hardware IOMMUs.
709 
710           The GART supports full DMA access for devices with 32-bit access
711           limitations, on systems with more than 3 GB. This is usually needed
712           for USB, sound, many IDE/SATA chipsets and some other devices.
713 
714           Newer systems typically have a modern AMD IOMMU, supported via
715           the CONFIG_AMD_IOMMU=y config option.
716 
717           In normal configurations this driver is only active when needed:
718           there's more than 3 GB of memory and the system contains a
719           32-bit limited device.
720 
721           If unsure, say Y.
722 
723 config CALGARY_IOMMU
724         bool "IBM Calgary IOMMU support"
725         select SWIOTLB
726         depends on X86_64 && PCI
727         ---help---
728           Support for hardware IOMMUs in IBM's xSeries x366 and x460
729           systems. Needed to run systems with more than 3GB of memory
730           properly with 32-bit PCI devices that do not support DAC
731           (Double Address Cycle). Calgary also supports bus level
732           isolation, where all DMAs pass through the IOMMU.  This
733           prevents them from going anywhere except their intended
734           destination. This catches hard-to-find kernel bugs and
735           mis-behaving drivers and devices that do not use the DMA-API
736           properly to set up their DMA buffers.  The IOMMU can be
737           turned off at boot time with the iommu=off parameter.
738           Normally the kernel will make the right choice by itself.
739           If unsure, say Y.
740 
741 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
742         def_bool y
743         prompt "Should Calgary be enabled by default?"
744         depends on CALGARY_IOMMU
745         ---help---
746           Should Calgary be enabled by default? if you choose 'y', Calgary
747           will be used (if it exists). If you choose 'n', Calgary will not be
748           used even if it exists. If you choose 'n' and would like to use
749           Calgary anyway, pass 'iommu=calgary' on the kernel command line.
750           If unsure, say Y.
751 
752 # need this always selected by IOMMU for the VIA workaround
753 config SWIOTLB
754         def_bool y if X86_64
755         ---help---
756           Support for software bounce buffers used on x86-64 systems
757           which don't have a hardware IOMMU. Using this PCI devices
758           which can only access 32-bits of memory can be used on systems
759           with more than 3 GB of memory.
760           If unsure, say Y.
761 
762 config IOMMU_HELPER
763         def_bool y
764         depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
765 
766 config MAXSMP
767         bool "Enable Maximum number of SMP Processors and NUMA Nodes"
768         depends on X86_64 && SMP && DEBUG_KERNEL
769         select CPUMASK_OFFSTACK
770         ---help---
771           Enable maximum number of CPUS and NUMA Nodes for this architecture.
772           If unsure, say N.
773 
774 config NR_CPUS
775         int "Maximum number of CPUs" if SMP && !MAXSMP
776         range 2 8 if SMP && X86_32 && !X86_BIGSMP
777         range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
778         range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
779         default "1" if !SMP
780         default "8192" if MAXSMP
781         default "32" if SMP && X86_BIGSMP
782         default "8" if SMP
783         ---help---
784           This allows you to specify the maximum number of CPUs which this
785           kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
786           supported value is 4096, otherwise the maximum value is 512.  The
787           minimum value which makes sense is 2.
788 
789           This is purely to save memory - each supported CPU adds
790           approximately eight kilobytes to the kernel image.
791 
792 config SCHED_SMT
793         bool "SMT (Hyperthreading) scheduler support"
794         depends on X86_HT
795         ---help---
796           SMT scheduler support improves the CPU scheduler's decision making
797           when dealing with Intel Pentium 4 chips with HyperThreading at a
798           cost of slightly increased overhead in some places. If unsure say
799           N here.
800 
801 config SCHED_MC
802         def_bool y
803         prompt "Multi-core scheduler support"
804         depends on X86_HT
805         ---help---
806           Multi-core scheduler support improves the CPU scheduler's decision
807           making when dealing with multi-core CPU chips at a cost of slightly
808           increased overhead in some places. If unsure say N here.
809 
810 source "kernel/Kconfig.preempt"
811 
812 config X86_UP_APIC
813         bool "Local APIC support on uniprocessors"
814         depends on X86_32 && !SMP && !X86_32_NON_STANDARD && !PCI_MSI
815         ---help---
816           A local APIC (Advanced Programmable Interrupt Controller) is an
817           integrated interrupt controller in the CPU. If you have a single-CPU
818           system which has a processor with a local APIC, you can say Y here to
819           enable and use it. If you say Y here even though your machine doesn't
820           have a local APIC, then the kernel will still run with no slowdown at
821           all. The local APIC supports CPU-generated self-interrupts (timer,
822           performance counters), and the NMI watchdog which detects hard
823           lockups.
824 
825 config X86_UP_IOAPIC
826         bool "IO-APIC support on uniprocessors"
827         depends on X86_UP_APIC
828         ---help---
829           An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
830           SMP-capable replacement for PC-style interrupt controllers. Most
831           SMP systems and many recent uniprocessor systems have one.
832 
833           If you have a single-CPU system with an IO-APIC, you can say Y here
834           to use it. If you say Y here even though your machine doesn't have
835           an IO-APIC, then the kernel will still run with no slowdown at all.
836 
837 config X86_LOCAL_APIC
838         def_bool y
839         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
840 
841 config X86_IO_APIC
842         def_bool y
843         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC || PCI_MSI
844         select GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
845         select IRQ_DOMAIN
846 
847 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
848         bool "Reroute for broken boot IRQs"
849         depends on X86_IO_APIC
850         ---help---
851           This option enables a workaround that fixes a source of
852           spurious interrupts. This is recommended when threaded
853           interrupt handling is used on systems where the generation of
854           superfluous "boot interrupts" cannot be disabled.
855 
856           Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
857           entry in the chipset's IO-APIC is masked (as, e.g. the RT
858           kernel does during interrupt handling). On chipsets where this
859           boot IRQ generation cannot be disabled, this workaround keeps
860           the original IRQ line masked so that only the equivalent "boot
861           IRQ" is delivered to the CPUs. The workaround also tells the
862           kernel to set up the IRQ handler on the boot IRQ line. In this
863           way only one interrupt is delivered to the kernel. Otherwise
864           the spurious second interrupt may cause the kernel to bring
865           down (vital) interrupt lines.
866 
867           Only affects "broken" chipsets. Interrupt sharing may be
868           increased on these systems.
869 
870 config X86_MCE
871         bool "Machine Check / overheating reporting"
872         default y
873         ---help---
874           Machine Check support allows the processor to notify the
875           kernel if it detects a problem (e.g. overheating, data corruption).
876           The action the kernel takes depends on the severity of the problem,
877           ranging from warning messages to halting the machine.
878 
879 config X86_MCE_INTEL
880         def_bool y
881         prompt "Intel MCE features"
882         depends on X86_MCE && X86_LOCAL_APIC
883         ---help---
884            Additional support for intel specific MCE features such as
885            the thermal monitor.
886 
887 config X86_MCE_AMD
888         def_bool y
889         prompt "AMD MCE features"
890         depends on X86_MCE && X86_LOCAL_APIC
891         ---help---
892            Additional support for AMD specific MCE features such as
893            the DRAM Error Threshold.
894 
895 config X86_ANCIENT_MCE
896         bool "Support for old Pentium 5 / WinChip machine checks"
897         depends on X86_32 && X86_MCE
898         ---help---
899           Include support for machine check handling on old Pentium 5 or WinChip
900           systems. These typically need to be enabled explicitly on the command
901           line.
902 
903 config X86_MCE_THRESHOLD
904         depends on X86_MCE_AMD || X86_MCE_INTEL
905         def_bool y
906 
907 config X86_MCE_INJECT
908         depends on X86_MCE
909         tristate "Machine check injector support"
910         ---help---
911           Provide support for injecting machine checks for testing purposes.
912           If you don't know what a machine check is and you don't do kernel
913           QA it is safe to say n.
914 
915 config X86_THERMAL_VECTOR
916         def_bool y
917         depends on X86_MCE_INTEL
918 
919 config VM86
920         bool "Enable VM86 support" if EXPERT
921         default y
922         depends on X86_32
923         ---help---
924           This option is required by programs like DOSEMU to run
925           16-bit real mode legacy code on x86 processors. It also may
926           be needed by software like XFree86 to initialize some video
927           cards via BIOS. Disabling this option saves about 6K.
928 
929 config X86_16BIT
930         bool "Enable support for 16-bit segments" if EXPERT
931         default y
932         ---help---
933           This option is required by programs like Wine to run 16-bit
934           protected mode legacy code on x86 processors.  Disabling
935           this option saves about 300 bytes on i386, or around 6K text
936           plus 16K runtime memory on x86-64,
937 
938 config X86_ESPFIX32
939         def_bool y
940         depends on X86_16BIT && X86_32
941 
942 config X86_ESPFIX64
943         def_bool y
944         depends on X86_16BIT && X86_64
945 
946 config TOSHIBA
947         tristate "Toshiba Laptop support"
948         depends on X86_32
949         ---help---
950           This adds a driver to safely access the System Management Mode of
951           the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
952           not work on models with a Phoenix BIOS. The System Management Mode
953           is used to set the BIOS and power saving options on Toshiba portables.
954 
955           For information on utilities to make use of this driver see the
956           Toshiba Linux utilities web site at:
957           <http://www.buzzard.org.uk/toshiba/>.
958 
959           Say Y if you intend to run this kernel on a Toshiba portable.
960           Say N otherwise.
961 
962 config I8K
963         tristate "Dell laptop support"
964         select HWMON
965         ---help---
966           This adds a driver to safely access the System Management Mode
967           of the CPU on the Dell Inspiron 8000. The System Management Mode
968           is used to read cpu temperature and cooling fan status and to
969           control the fans on the I8K portables.
970 
971           This driver has been tested only on the Inspiron 8000 but it may
972           also work with other Dell laptops. You can force loading on other
973           models by passing the parameter `force=1' to the module. Use at
974           your own risk.
975 
976           For information on utilities to make use of this driver see the
977           I8K Linux utilities web site at:
978           <http://people.debian.org/~dz/i8k/>
979 
980           Say Y if you intend to run this kernel on a Dell Inspiron 8000.
981           Say N otherwise.
982 
983 config X86_REBOOTFIXUPS
984         bool "Enable X86 board specific fixups for reboot"
985         depends on X86_32
986         ---help---
987           This enables chipset and/or board specific fixups to be done
988           in order to get reboot to work correctly. This is only needed on
989           some combinations of hardware and BIOS. The symptom, for which
990           this config is intended, is when reboot ends with a stalled/hung
991           system.
992 
993           Currently, the only fixup is for the Geode machines using
994           CS5530A and CS5536 chipsets and the RDC R-321x SoC.
995 
996           Say Y if you want to enable the fixup. Currently, it's safe to
997           enable this option even if you don't need it.
998           Say N otherwise.
999 
1000 config MICROCODE
1001         tristate "CPU microcode loading support"
1002         depends on CPU_SUP_AMD || CPU_SUP_INTEL
1003         select FW_LOADER
1004         ---help---
1005 
1006           If you say Y here, you will be able to update the microcode on
1007           certain Intel and AMD processors. The Intel support is for the
1008           IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1009           Xeon etc. The AMD support is for families 0x10 and later. You will
1010           obviously need the actual microcode binary data itself which is not
1011           shipped with the Linux kernel.
1012 
1013           This option selects the general module only, you need to select
1014           at least one vendor specific module as well.
1015 
1016           To compile this driver as a module, choose M here: the module
1017           will be called microcode.
1018 
1019 config MICROCODE_INTEL
1020         bool "Intel microcode loading support"
1021         depends on MICROCODE
1022         default MICROCODE
1023         select FW_LOADER
1024         ---help---
1025           This options enables microcode patch loading support for Intel
1026           processors.
1027 
1028           For the current Intel microcode data package go to
1029           <https://downloadcenter.intel.com> and search for
1030           'Linux Processor Microcode Data File'.
1031 
1032 config MICROCODE_AMD
1033         bool "AMD microcode loading support"
1034         depends on MICROCODE
1035         select FW_LOADER
1036         ---help---
1037           If you select this option, microcode patch loading support for AMD
1038           processors will be enabled.
1039 
1040 config MICROCODE_OLD_INTERFACE
1041         def_bool y
1042         depends on MICROCODE
1043 
1044 config MICROCODE_INTEL_EARLY
1045         def_bool n
1046 
1047 config MICROCODE_AMD_EARLY
1048         def_bool n
1049 
1050 config MICROCODE_EARLY
1051         bool "Early load microcode"
1052         depends on MICROCODE=y && BLK_DEV_INITRD
1053         select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1054         select MICROCODE_AMD_EARLY if MICROCODE_AMD
1055         default y
1056         help
1057           This option provides functionality to read additional microcode data
1058           at the beginning of initrd image. The data tells kernel to load
1059           microcode to CPU's as early as possible. No functional change if no
1060           microcode data is glued to the initrd, therefore it's safe to say Y.
1061 
1062 config X86_MSR
1063         tristate "/dev/cpu/*/msr - Model-specific register support"
1064         ---help---
1065           This device gives privileged processes access to the x86
1066           Model-Specific Registers (MSRs).  It is a character device with
1067           major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1068           MSR accesses are directed to a specific CPU on multi-processor
1069           systems.
1070 
1071 config X86_CPUID
1072         tristate "/dev/cpu/*/cpuid - CPU information support"
1073         ---help---
1074           This device gives processes access to the x86 CPUID instruction to
1075           be executed on a specific processor.  It is a character device
1076           with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1077           /dev/cpu/31/cpuid.
1078 
1079 choice
1080         prompt "High Memory Support"
1081         default HIGHMEM4G
1082         depends on X86_32
1083 
1084 config NOHIGHMEM
1085         bool "off"
1086         ---help---
1087           Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1088           However, the address space of 32-bit x86 processors is only 4
1089           Gigabytes large. That means that, if you have a large amount of
1090           physical memory, not all of it can be "permanently mapped" by the
1091           kernel. The physical memory that's not permanently mapped is called
1092           "high memory".
1093 
1094           If you are compiling a kernel which will never run on a machine with
1095           more than 1 Gigabyte total physical RAM, answer "off" here (default
1096           choice and suitable for most users). This will result in a "3GB/1GB"
1097           split: 3GB are mapped so that each process sees a 3GB virtual memory
1098           space and the remaining part of the 4GB virtual memory space is used
1099           by the kernel to permanently map as much physical memory as
1100           possible.
1101 
1102           If the machine has between 1 and 4 Gigabytes physical RAM, then
1103           answer "4GB" here.
1104 
1105           If more than 4 Gigabytes is used then answer "64GB" here. This
1106           selection turns Intel PAE (Physical Address Extension) mode on.
1107           PAE implements 3-level paging on IA32 processors. PAE is fully
1108           supported by Linux, PAE mode is implemented on all recent Intel
1109           processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1110           then the kernel will not boot on CPUs that don't support PAE!
1111 
1112           The actual amount of total physical memory will either be
1113           auto detected or can be forced by using a kernel command line option
1114           such as "mem=256M". (Try "man bootparam" or see the documentation of
1115           your boot loader (lilo or loadlin) about how to pass options to the
1116           kernel at boot time.)
1117 
1118           If unsure, say "off".
1119 
1120 config HIGHMEM4G
1121         bool "4GB"
1122         ---help---
1123           Select this if you have a 32-bit processor and between 1 and 4
1124           gigabytes of physical RAM.
1125 
1126 config HIGHMEM64G
1127         bool "64GB"
1128         depends on !M486
1129         select X86_PAE
1130         ---help---
1131           Select this if you have a 32-bit processor and more than 4
1132           gigabytes of physical RAM.
1133 
1134 endchoice
1135 
1136 choice
1137         prompt "Memory split" if EXPERT
1138         default VMSPLIT_3G
1139         depends on X86_32
1140         ---help---
1141           Select the desired split between kernel and user memory.
1142 
1143           If the address range available to the kernel is less than the
1144           physical memory installed, the remaining memory will be available
1145           as "high memory". Accessing high memory is a little more costly
1146           than low memory, as it needs to be mapped into the kernel first.
1147           Note that increasing the kernel address space limits the range
1148           available to user programs, making the address space there
1149           tighter.  Selecting anything other than the default 3G/1G split
1150           will also likely make your kernel incompatible with binary-only
1151           kernel modules.
1152 
1153           If you are not absolutely sure what you are doing, leave this
1154           option alone!
1155 
1156         config VMSPLIT_3G
1157                 bool "3G/1G user/kernel split"
1158         config VMSPLIT_3G_OPT
1159                 depends on !X86_PAE
1160                 bool "3G/1G user/kernel split (for full 1G low memory)"
1161         config VMSPLIT_2G
1162                 bool "2G/2G user/kernel split"
1163         config VMSPLIT_2G_OPT
1164                 depends on !X86_PAE
1165                 bool "2G/2G user/kernel split (for full 2G low memory)"
1166         config VMSPLIT_1G
1167                 bool "1G/3G user/kernel split"
1168 endchoice
1169 
1170 config PAGE_OFFSET
1171         hex
1172         default 0xB0000000 if VMSPLIT_3G_OPT
1173         default 0x80000000 if VMSPLIT_2G
1174         default 0x78000000 if VMSPLIT_2G_OPT
1175         default 0x40000000 if VMSPLIT_1G
1176         default 0xC0000000
1177         depends on X86_32
1178 
1179 config HIGHMEM
1180         def_bool y
1181         depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1182 
1183 config X86_PAE
1184         bool "PAE (Physical Address Extension) Support"
1185         depends on X86_32 && !HIGHMEM4G
1186         ---help---
1187           PAE is required for NX support, and furthermore enables
1188           larger swapspace support for non-overcommit purposes. It
1189           has the cost of more pagetable lookup overhead, and also
1190           consumes more pagetable space per process.
1191 
1192 config ARCH_PHYS_ADDR_T_64BIT
1193         def_bool y
1194         depends on X86_64 || X86_PAE
1195 
1196 config ARCH_DMA_ADDR_T_64BIT
1197         def_bool y
1198         depends on X86_64 || HIGHMEM64G
1199 
1200 config DIRECT_GBPAGES
1201         bool "Enable 1GB pages for kernel pagetables" if EXPERT
1202         default y
1203         depends on X86_64
1204         ---help---
1205           Allow the kernel linear mapping to use 1GB pages on CPUs that
1206           support it. This can improve the kernel's performance a tiny bit by
1207           reducing TLB pressure. If in doubt, say "Y".
1208 
1209 # Common NUMA Features
1210 config NUMA
1211         bool "Numa Memory Allocation and Scheduler Support"
1212         depends on SMP
1213         depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1214         default y if X86_BIGSMP
1215         ---help---
1216           Enable NUMA (Non Uniform Memory Access) support.
1217 
1218           The kernel will try to allocate memory used by a CPU on the
1219           local memory controller of the CPU and add some more
1220           NUMA awareness to the kernel.
1221 
1222           For 64-bit this is recommended if the system is Intel Core i7
1223           (or later), AMD Opteron, or EM64T NUMA.
1224 
1225           For 32-bit this is only needed if you boot a 32-bit
1226           kernel on a 64-bit NUMA platform.
1227 
1228           Otherwise, you should say N.
1229 
1230 config AMD_NUMA
1231         def_bool y
1232         prompt "Old style AMD Opteron NUMA detection"
1233         depends on X86_64 && NUMA && PCI
1234         ---help---
1235           Enable AMD NUMA node topology detection.  You should say Y here if
1236           you have a multi processor AMD system. This uses an old method to
1237           read the NUMA configuration directly from the builtin Northbridge
1238           of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1239           which also takes priority if both are compiled in.
1240 
1241 config X86_64_ACPI_NUMA
1242         def_bool y
1243         prompt "ACPI NUMA detection"
1244         depends on X86_64 && NUMA && ACPI && PCI
1245         select ACPI_NUMA
1246         ---help---
1247           Enable ACPI SRAT based node topology detection.
1248 
1249 # Some NUMA nodes have memory ranges that span
1250 # other nodes.  Even though a pfn is valid and
1251 # between a node's start and end pfns, it may not
1252 # reside on that node.  See memmap_init_zone()
1253 # for details.
1254 config NODES_SPAN_OTHER_NODES
1255         def_bool y
1256         depends on X86_64_ACPI_NUMA
1257 
1258 config NUMA_EMU
1259         bool "NUMA emulation"
1260         depends on NUMA
1261         ---help---
1262           Enable NUMA emulation. A flat machine will be split
1263           into virtual nodes when booted with "numa=fake=N", where N is the
1264           number of nodes. This is only useful for debugging.
1265 
1266 config NODES_SHIFT
1267         int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1268         range 1 10
1269         default "10" if MAXSMP
1270         default "6" if X86_64
1271         default "3"
1272         depends on NEED_MULTIPLE_NODES
1273         ---help---
1274           Specify the maximum number of NUMA Nodes available on the target
1275           system.  Increases memory reserved to accommodate various tables.
1276 
1277 config ARCH_HAVE_MEMORY_PRESENT
1278         def_bool y
1279         depends on X86_32 && DISCONTIGMEM
1280 
1281 config NEED_NODE_MEMMAP_SIZE
1282         def_bool y
1283         depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1284 
1285 config ARCH_FLATMEM_ENABLE
1286         def_bool y
1287         depends on X86_32 && !NUMA
1288 
1289 config ARCH_DISCONTIGMEM_ENABLE
1290         def_bool y
1291         depends on NUMA && X86_32
1292 
1293 config ARCH_DISCONTIGMEM_DEFAULT
1294         def_bool y
1295         depends on NUMA && X86_32
1296 
1297 config ARCH_SPARSEMEM_ENABLE
1298         def_bool y
1299         depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1300         select SPARSEMEM_STATIC if X86_32
1301         select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1302 
1303 config ARCH_SPARSEMEM_DEFAULT
1304         def_bool y
1305         depends on X86_64
1306 
1307 config ARCH_SELECT_MEMORY_MODEL
1308         def_bool y
1309         depends on ARCH_SPARSEMEM_ENABLE
1310 
1311 config ARCH_MEMORY_PROBE
1312         bool "Enable sysfs memory/probe interface"
1313         depends on X86_64 && MEMORY_HOTPLUG
1314         help
1315           This option enables a sysfs memory/probe interface for testing.
1316           See Documentation/memory-hotplug.txt for more information.
1317           If you are unsure how to answer this question, answer N.
1318 
1319 config ARCH_PROC_KCORE_TEXT
1320         def_bool y
1321         depends on X86_64 && PROC_KCORE
1322 
1323 config ILLEGAL_POINTER_VALUE
1324        hex
1325        default 0 if X86_32
1326        default 0xdead000000000000 if X86_64
1327 
1328 source "mm/Kconfig"
1329 
1330 config HIGHPTE
1331         bool "Allocate 3rd-level pagetables from highmem"
1332         depends on HIGHMEM
1333         ---help---
1334           The VM uses one page table entry for each page of physical memory.
1335           For systems with a lot of RAM, this can be wasteful of precious
1336           low memory.  Setting this option will put user-space page table
1337           entries in high memory.
1338 
1339 config X86_CHECK_BIOS_CORRUPTION
1340         bool "Check for low memory corruption"
1341         ---help---
1342           Periodically check for memory corruption in low memory, which
1343           is suspected to be caused by BIOS.  Even when enabled in the
1344           configuration, it is disabled at runtime.  Enable it by
1345           setting "memory_corruption_check=1" on the kernel command
1346           line.  By default it scans the low 64k of memory every 60
1347           seconds; see the memory_corruption_check_size and
1348           memory_corruption_check_period parameters in
1349           Documentation/kernel-parameters.txt to adjust this.
1350 
1351           When enabled with the default parameters, this option has
1352           almost no overhead, as it reserves a relatively small amount
1353           of memory and scans it infrequently.  It both detects corruption
1354           and prevents it from affecting the running system.
1355 
1356           It is, however, intended as a diagnostic tool; if repeatable
1357           BIOS-originated corruption always affects the same memory,
1358           you can use memmap= to prevent the kernel from using that
1359           memory.
1360 
1361 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1362         bool "Set the default setting of memory_corruption_check"
1363         depends on X86_CHECK_BIOS_CORRUPTION
1364         default y
1365         ---help---
1366           Set whether the default state of memory_corruption_check is
1367           on or off.
1368 
1369 config X86_RESERVE_LOW
1370         int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1371         default 64
1372         range 4 640
1373         ---help---
1374           Specify the amount of low memory to reserve for the BIOS.
1375 
1376           The first page contains BIOS data structures that the kernel
1377           must not use, so that page must always be reserved.
1378 
1379           By default we reserve the first 64K of physical RAM, as a
1380           number of BIOSes are known to corrupt that memory range
1381           during events such as suspend/resume or monitor cable
1382           insertion, so it must not be used by the kernel.
1383 
1384           You can set this to 4 if you are absolutely sure that you
1385           trust the BIOS to get all its memory reservations and usages
1386           right.  If you know your BIOS have problems beyond the
1387           default 64K area, you can set this to 640 to avoid using the
1388           entire low memory range.
1389 
1390           If you have doubts about the BIOS (e.g. suspend/resume does
1391           not work or there's kernel crashes after certain hardware
1392           hotplug events) then you might want to enable
1393           X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1394           typical corruption patterns.
1395 
1396           Leave this to the default value of 64 if you are unsure.
1397 
1398 config MATH_EMULATION
1399         bool
1400         prompt "Math emulation" if X86_32
1401         ---help---
1402           Linux can emulate a math coprocessor (used for floating point
1403           operations) if you don't have one. 486DX and Pentium processors have
1404           a math coprocessor built in, 486SX and 386 do not, unless you added
1405           a 487DX or 387, respectively. (The messages during boot time can
1406           give you some hints here ["man dmesg"].) Everyone needs either a
1407           coprocessor or this emulation.
1408 
1409           If you don't have a math coprocessor, you need to say Y here; if you
1410           say Y here even though you have a coprocessor, the coprocessor will
1411           be used nevertheless. (This behavior can be changed with the kernel
1412           command line option "no387", which comes handy if your coprocessor
1413           is broken. Try "man bootparam" or see the documentation of your boot
1414           loader (lilo or loadlin) about how to pass options to the kernel at
1415           boot time.) This means that it is a good idea to say Y here if you
1416           intend to use this kernel on different machines.
1417 
1418           More information about the internals of the Linux math coprocessor
1419           emulation can be found in <file:arch/x86/math-emu/README>.
1420 
1421           If you are not sure, say Y; apart from resulting in a 66 KB bigger
1422           kernel, it won't hurt.
1423 
1424 config MTRR
1425         def_bool y
1426         prompt "MTRR (Memory Type Range Register) support" if EXPERT
1427         ---help---
1428           On Intel P6 family processors (Pentium Pro, Pentium II and later)
1429           the Memory Type Range Registers (MTRRs) may be used to control
1430           processor access to memory ranges. This is most useful if you have
1431           a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1432           allows bus write transfers to be combined into a larger transfer
1433           before bursting over the PCI/AGP bus. This can increase performance
1434           of image write operations 2.5 times or more. Saying Y here creates a
1435           /proc/mtrr file which may be used to manipulate your processor's
1436           MTRRs. Typically the X server should use this.
1437 
1438           This code has a reasonably generic interface so that similar
1439           control registers on other processors can be easily supported
1440           as well:
1441 
1442           The Cyrix 6x86, 6x86MX and M II processors have Address Range
1443           Registers (ARRs) which provide a similar functionality to MTRRs. For
1444           these, the ARRs are used to emulate the MTRRs.
1445           The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1446           MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1447           write-combining. All of these processors are supported by this code
1448           and it makes sense to say Y here if you have one of them.
1449 
1450           Saying Y here also fixes a problem with buggy SMP BIOSes which only
1451           set the MTRRs for the boot CPU and not for the secondary CPUs. This
1452           can lead to all sorts of problems, so it's good to say Y here.
1453 
1454           You can safely say Y even if your machine doesn't have MTRRs, you'll
1455           just add about 9 KB to your kernel.
1456 
1457           See <file:Documentation/x86/mtrr.txt> for more information.
1458 
1459 config MTRR_SANITIZER
1460         def_bool y
1461         prompt "MTRR cleanup support"
1462         depends on MTRR
1463         ---help---
1464           Convert MTRR layout from continuous to discrete, so X drivers can
1465           add writeback entries.
1466 
1467           Can be disabled with disable_mtrr_cleanup on the kernel command line.
1468           The largest mtrr entry size for a continuous block can be set with
1469           mtrr_chunk_size.
1470 
1471           If unsure, say Y.
1472 
1473 config MTRR_SANITIZER_ENABLE_DEFAULT
1474         int "MTRR cleanup enable value (0-1)"
1475         range 0 1
1476         default "0"
1477         depends on MTRR_SANITIZER
1478         ---help---
1479           Enable mtrr cleanup default value
1480 
1481 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1482         int "MTRR cleanup spare reg num (0-7)"
1483         range 0 7
1484         default "1"
1485         depends on MTRR_SANITIZER
1486         ---help---
1487           mtrr cleanup spare entries default, it can be changed via
1488           mtrr_spare_reg_nr=N on the kernel command line.
1489 
1490 config X86_PAT
1491         def_bool y
1492         prompt "x86 PAT support" if EXPERT
1493         depends on MTRR
1494         ---help---
1495           Use PAT attributes to setup page level cache control.
1496 
1497           PATs are the modern equivalents of MTRRs and are much more
1498           flexible than MTRRs.
1499 
1500           Say N here if you see bootup problems (boot crash, boot hang,
1501           spontaneous reboots) or a non-working video driver.
1502 
1503           If unsure, say Y.
1504 
1505 config ARCH_USES_PG_UNCACHED
1506         def_bool y
1507         depends on X86_PAT
1508 
1509 config ARCH_RANDOM
1510         def_bool y
1511         prompt "x86 architectural random number generator" if EXPERT
1512         ---help---
1513           Enable the x86 architectural RDRAND instruction
1514           (Intel Bull Mountain technology) to generate random numbers.
1515           If supported, this is a high bandwidth, cryptographically
1516           secure hardware random number generator.
1517 
1518 config X86_SMAP
1519         def_bool y
1520         prompt "Supervisor Mode Access Prevention" if EXPERT
1521         ---help---
1522           Supervisor Mode Access Prevention (SMAP) is a security
1523           feature in newer Intel processors.  There is a small
1524           performance cost if this enabled and turned on; there is
1525           also a small increase in the kernel size if this is enabled.
1526 
1527           If unsure, say Y.
1528 
1529 config EFI
1530         bool "EFI runtime service support"
1531         depends on ACPI
1532         select UCS2_STRING
1533         select EFI_RUNTIME_WRAPPERS
1534         ---help---
1535           This enables the kernel to use EFI runtime services that are
1536           available (such as the EFI variable services).
1537 
1538           This option is only useful on systems that have EFI firmware.
1539           In addition, you should use the latest ELILO loader available
1540           at <http://elilo.sourceforge.net> in order to take advantage
1541           of EFI runtime services. However, even with this option, the
1542           resultant kernel should continue to boot on existing non-EFI
1543           platforms.
1544 
1545 config EFI_STUB
1546        bool "EFI stub support"
1547        depends on EFI && !X86_USE_3DNOW
1548        select RELOCATABLE
1549        ---help---
1550           This kernel feature allows a bzImage to be loaded directly
1551           by EFI firmware without the use of a bootloader.
1552 
1553           See Documentation/efi-stub.txt for more information.
1554 
1555 config EFI_MIXED
1556         bool "EFI mixed-mode support"
1557         depends on EFI_STUB && X86_64
1558         ---help---
1559            Enabling this feature allows a 64-bit kernel to be booted
1560            on a 32-bit firmware, provided that your CPU supports 64-bit
1561            mode.
1562 
1563            Note that it is not possible to boot a mixed-mode enabled
1564            kernel via the EFI boot stub - a bootloader that supports
1565            the EFI handover protocol must be used.
1566 
1567            If unsure, say N.
1568 
1569 config SECCOMP
1570         def_bool y
1571         prompt "Enable seccomp to safely compute untrusted bytecode"
1572         ---help---
1573           This kernel feature is useful for number crunching applications
1574           that may need to compute untrusted bytecode during their
1575           execution. By using pipes or other transports made available to
1576           the process as file descriptors supporting the read/write
1577           syscalls, it's possible to isolate those applications in
1578           their own address space using seccomp. Once seccomp is
1579           enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1580           and the task is only allowed to execute a few safe syscalls
1581           defined by each seccomp mode.
1582 
1583           If unsure, say Y. Only embedded should say N here.
1584 
1585 source kernel/Kconfig.hz
1586 
1587 config KEXEC
1588         bool "kexec system call"
1589         ---help---
1590           kexec is a system call that implements the ability to shutdown your
1591           current kernel, and to start another kernel.  It is like a reboot
1592           but it is independent of the system firmware.   And like a reboot
1593           you can start any kernel with it, not just Linux.
1594 
1595           The name comes from the similarity to the exec system call.
1596 
1597           It is an ongoing process to be certain the hardware in a machine
1598           is properly shutdown, so do not be surprised if this code does not
1599           initially work for you.  As of this writing the exact hardware
1600           interface is strongly in flux, so no good recommendation can be
1601           made.
1602 
1603 config KEXEC_FILE
1604         bool "kexec file based system call"
1605         select BUILD_BIN2C
1606         depends on KEXEC
1607         depends on X86_64
1608         depends on CRYPTO=y
1609         depends on CRYPTO_SHA256=y
1610         ---help---
1611           This is new version of kexec system call. This system call is
1612           file based and takes file descriptors as system call argument
1613           for kernel and initramfs as opposed to list of segments as
1614           accepted by previous system call.
1615 
1616 config KEXEC_VERIFY_SIG
1617         bool "Verify kernel signature during kexec_file_load() syscall"
1618         depends on KEXEC_FILE
1619         ---help---
1620           This option makes kernel signature verification mandatory for
1621           kexec_file_load() syscall. If kernel is signature can not be
1622           verified, kexec_file_load() will fail.
1623 
1624           This option enforces signature verification at generic level.
1625           One needs to enable signature verification for type of kernel
1626           image being loaded to make sure it works. For example, enable
1627           bzImage signature verification option to be able to load and
1628           verify signatures of bzImage. Otherwise kernel loading will fail.
1629 
1630 config KEXEC_BZIMAGE_VERIFY_SIG
1631         bool "Enable bzImage signature verification support"
1632         depends on KEXEC_VERIFY_SIG
1633         depends on SIGNED_PE_FILE_VERIFICATION
1634         select SYSTEM_TRUSTED_KEYRING
1635         ---help---
1636           Enable bzImage signature verification support.
1637 
1638 config CRASH_DUMP
1639         bool "kernel crash dumps"
1640         depends on X86_64 || (X86_32 && HIGHMEM)
1641         ---help---
1642           Generate crash dump after being started by kexec.
1643           This should be normally only set in special crash dump kernels
1644           which are loaded in the main kernel with kexec-tools into
1645           a specially reserved region and then later executed after
1646           a crash by kdump/kexec. The crash dump kernel must be compiled
1647           to a memory address not used by the main kernel or BIOS using
1648           PHYSICAL_START, or it must be built as a relocatable image
1649           (CONFIG_RELOCATABLE=y).
1650           For more details see Documentation/kdump/kdump.txt
1651 
1652 config KEXEC_JUMP
1653         bool "kexec jump"
1654         depends on KEXEC && HIBERNATION
1655         ---help---
1656           Jump between original kernel and kexeced kernel and invoke
1657           code in physical address mode via KEXEC
1658 
1659 config PHYSICAL_START
1660         hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1661         default "0x1000000"
1662         ---help---
1663           This gives the physical address where the kernel is loaded.
1664 
1665           If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1666           bzImage will decompress itself to above physical address and
1667           run from there. Otherwise, bzImage will run from the address where
1668           it has been loaded by the boot loader and will ignore above physical
1669           address.
1670 
1671           In normal kdump cases one does not have to set/change this option
1672           as now bzImage can be compiled as a completely relocatable image
1673           (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1674           address. This option is mainly useful for the folks who don't want
1675           to use a bzImage for capturing the crash dump and want to use a
1676           vmlinux instead. vmlinux is not relocatable hence a kernel needs
1677           to be specifically compiled to run from a specific memory area
1678           (normally a reserved region) and this option comes handy.
1679 
1680           So if you are using bzImage for capturing the crash dump,
1681           leave the value here unchanged to 0x1000000 and set
1682           CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
1683           for capturing the crash dump change this value to start of
1684           the reserved region.  In other words, it can be set based on
1685           the "X" value as specified in the "crashkernel=YM@XM"
1686           command line boot parameter passed to the panic-ed
1687           kernel. Please take a look at Documentation/kdump/kdump.txt
1688           for more details about crash dumps.
1689 
1690           Usage of bzImage for capturing the crash dump is recommended as
1691           one does not have to build two kernels. Same kernel can be used
1692           as production kernel and capture kernel. Above option should have
1693           gone away after relocatable bzImage support is introduced. But it
1694           is present because there are users out there who continue to use
1695           vmlinux for dump capture. This option should go away down the
1696           line.
1697 
1698           Don't change this unless you know what you are doing.
1699 
1700 config RELOCATABLE
1701         bool "Build a relocatable kernel"
1702         default y
1703         ---help---
1704           This builds a kernel image that retains relocation information
1705           so it can be loaded someplace besides the default 1MB.
1706           The relocations tend to make the kernel binary about 10% larger,
1707           but are discarded at runtime.
1708 
1709           One use is for the kexec on panic case where the recovery kernel
1710           must live at a different physical address than the primary
1711           kernel.
1712 
1713           Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1714           it has been loaded at and the compile time physical address
1715           (CONFIG_PHYSICAL_START) is used as the minimum location.
1716 
1717 config RANDOMIZE_BASE
1718         bool "Randomize the address of the kernel image"
1719         depends on RELOCATABLE
1720         default n
1721         ---help---
1722            Randomizes the physical and virtual address at which the
1723            kernel image is decompressed, as a security feature that
1724            deters exploit attempts relying on knowledge of the location
1725            of kernel internals.
1726 
1727            Entropy is generated using the RDRAND instruction if it is
1728            supported. If RDTSC is supported, it is used as well. If
1729            neither RDRAND nor RDTSC are supported, then randomness is
1730            read from the i8254 timer.
1731 
1732            The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1733            and aligned according to PHYSICAL_ALIGN. Since the kernel is
1734            built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1735            minimum of 2MiB, only 10 bits of entropy is theoretically
1736            possible. At best, due to page table layouts, 64-bit can use
1737            9 bits of entropy and 32-bit uses 8 bits.
1738 
1739            If unsure, say N.
1740 
1741 config RANDOMIZE_BASE_MAX_OFFSET
1742         hex "Maximum kASLR offset allowed" if EXPERT
1743         depends on RANDOMIZE_BASE
1744         range 0x0 0x20000000 if X86_32
1745         default "0x20000000" if X86_32
1746         range 0x0 0x40000000 if X86_64
1747         default "0x40000000" if X86_64
1748         ---help---
1749           The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1750           memory is used to determine the maximal offset in bytes that will
1751           be applied to the kernel when kernel Address Space Layout
1752           Randomization (kASLR) is active. This must be a multiple of
1753           PHYSICAL_ALIGN.
1754 
1755           On 32-bit this is limited to 512MiB by page table layouts. The
1756           default is 512MiB.
1757 
1758           On 64-bit this is limited by how the kernel fixmap page table is
1759           positioned, so this cannot be larger than 1GiB currently. Without
1760           RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1761           and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1762           modules area will shrink to compensate, up to the current maximum
1763           1GiB to 1GiB split. The default is 1GiB.
1764 
1765           If unsure, leave at the default value.
1766 
1767 # Relocation on x86 needs some additional build support
1768 config X86_NEED_RELOCS
1769         def_bool y
1770         depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1771 
1772 config PHYSICAL_ALIGN
1773         hex "Alignment value to which kernel should be aligned"
1774         default "0x200000"
1775         range 0x2000 0x1000000 if X86_32
1776         range 0x200000 0x1000000 if X86_64
1777         ---help---
1778           This value puts the alignment restrictions on physical address
1779           where kernel is loaded and run from. Kernel is compiled for an
1780           address which meets above alignment restriction.
1781 
1782           If bootloader loads the kernel at a non-aligned address and
1783           CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1784           address aligned to above value and run from there.
1785 
1786           If bootloader loads the kernel at a non-aligned address and
1787           CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1788           load address and decompress itself to the address it has been
1789           compiled for and run from there. The address for which kernel is
1790           compiled already meets above alignment restrictions. Hence the
1791           end result is that kernel runs from a physical address meeting
1792           above alignment restrictions.
1793 
1794           On 32-bit this value must be a multiple of 0x2000. On 64-bit
1795           this value must be a multiple of 0x200000.
1796 
1797           Don't change this unless you know what you are doing.
1798 
1799 config HOTPLUG_CPU
1800         bool "Support for hot-pluggable CPUs"
1801         depends on SMP
1802         ---help---
1803           Say Y here to allow turning CPUs off and on. CPUs can be
1804           controlled through /sys/devices/system/cpu.
1805           ( Note: power management support will enable this option
1806             automatically on SMP systems. )
1807           Say N if you want to disable CPU hotplug.
1808 
1809 config BOOTPARAM_HOTPLUG_CPU0
1810         bool "Set default setting of cpu0_hotpluggable"
1811         default n
1812         depends on HOTPLUG_CPU
1813         ---help---
1814           Set whether default state of cpu0_hotpluggable is on or off.
1815 
1816           Say Y here to enable CPU0 hotplug by default. If this switch
1817           is turned on, there is no need to give cpu0_hotplug kernel
1818           parameter and the CPU0 hotplug feature is enabled by default.
1819 
1820           Please note: there are two known CPU0 dependencies if you want
1821           to enable the CPU0 hotplug feature either by this switch or by
1822           cpu0_hotplug kernel parameter.
1823 
1824           First, resume from hibernate or suspend always starts from CPU0.
1825           So hibernate and suspend are prevented if CPU0 is offline.
1826 
1827           Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1828           offline if any interrupt can not migrate out of CPU0. There may
1829           be other CPU0 dependencies.
1830 
1831           Please make sure the dependencies are under your control before
1832           you enable this feature.
1833 
1834           Say N if you don't want to enable CPU0 hotplug feature by default.
1835           You still can enable the CPU0 hotplug feature at boot by kernel
1836           parameter cpu0_hotplug.
1837 
1838 config DEBUG_HOTPLUG_CPU0
1839         def_bool n
1840         prompt "Debug CPU0 hotplug"
1841         depends on HOTPLUG_CPU
1842         ---help---
1843           Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1844           soon as possible and boots up userspace with CPU0 offlined. User
1845           can online CPU0 back after boot time.
1846 
1847           To debug CPU0 hotplug, you need to enable CPU0 offline/online
1848           feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1849           compilation or giving cpu0_hotplug kernel parameter at boot.
1850 
1851           If unsure, say N.
1852 
1853 config COMPAT_VDSO
1854         def_bool n
1855         prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
1856         depends on X86_32 || IA32_EMULATION
1857         ---help---
1858           Certain buggy versions of glibc will crash if they are
1859           presented with a 32-bit vDSO that is not mapped at the address
1860           indicated in its segment table.
1861 
1862           The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
1863           and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
1864           49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
1865           the only released version with the bug, but OpenSUSE 9
1866           contains a buggy "glibc 2.3.2".
1867 
1868           The symptom of the bug is that everything crashes on startup, saying:
1869           dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
1870 
1871           Saying Y here changes the default value of the vdso32 boot
1872           option from 1 to 0, which turns off the 32-bit vDSO entirely.
1873           This works around the glibc bug but hurts performance.
1874 
1875           If unsure, say N: if you are compiling your own kernel, you
1876           are unlikely to be using a buggy version of glibc.
1877 
1878 config CMDLINE_BOOL
1879         bool "Built-in kernel command line"
1880         ---help---
1881           Allow for specifying boot arguments to the kernel at
1882           build time.  On some systems (e.g. embedded ones), it is
1883           necessary or convenient to provide some or all of the
1884           kernel boot arguments with the kernel itself (that is,
1885           to not rely on the boot loader to provide them.)
1886 
1887           To compile command line arguments into the kernel,
1888           set this option to 'Y', then fill in the
1889           the boot arguments in CONFIG_CMDLINE.
1890 
1891           Systems with fully functional boot loaders (i.e. non-embedded)
1892           should leave this option set to 'N'.
1893 
1894 config CMDLINE
1895         string "Built-in kernel command string"
1896         depends on CMDLINE_BOOL
1897         default ""
1898         ---help---
1899           Enter arguments here that should be compiled into the kernel
1900           image and used at boot time.  If the boot loader provides a
1901           command line at boot time, it is appended to this string to
1902           form the full kernel command line, when the system boots.
1903 
1904           However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1905           change this behavior.
1906 
1907           In most cases, the command line (whether built-in or provided
1908           by the boot loader) should specify the device for the root
1909           file system.
1910 
1911 config CMDLINE_OVERRIDE
1912         bool "Built-in command line overrides boot loader arguments"
1913         depends on CMDLINE_BOOL
1914         ---help---
1915           Set this option to 'Y' to have the kernel ignore the boot loader
1916           command line, and use ONLY the built-in command line.
1917 
1918           This is used to work around broken boot loaders.  This should
1919           be set to 'N' under normal conditions.
1920 
1921 endmenu
1922 
1923 config ARCH_ENABLE_MEMORY_HOTPLUG
1924         def_bool y
1925         depends on X86_64 || (X86_32 && HIGHMEM)
1926 
1927 config ARCH_ENABLE_MEMORY_HOTREMOVE
1928         def_bool y
1929         depends on MEMORY_HOTPLUG
1930 
1931 config USE_PERCPU_NUMA_NODE_ID
1932         def_bool y
1933         depends on NUMA
1934 
1935 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1936         def_bool y
1937         depends on X86_64 || X86_PAE
1938 
1939 config ARCH_ENABLE_HUGEPAGE_MIGRATION
1940         def_bool y
1941         depends on X86_64 && HUGETLB_PAGE && MIGRATION
1942 
1943 menu "Power management and ACPI options"
1944 
1945 config ARCH_HIBERNATION_HEADER
1946         def_bool y
1947         depends on X86_64 && HIBERNATION
1948 
1949 source "kernel/power/Kconfig"
1950 
1951 source "drivers/acpi/Kconfig"
1952 
1953 source "drivers/sfi/Kconfig"
1954 
1955 config X86_APM_BOOT
1956         def_bool y
1957         depends on APM
1958 
1959 menuconfig APM
1960         tristate "APM (Advanced Power Management) BIOS support"
1961         depends on X86_32 && PM_SLEEP
1962         ---help---
1963           APM is a BIOS specification for saving power using several different
1964           techniques. This is mostly useful for battery powered laptops with
1965           APM compliant BIOSes. If you say Y here, the system time will be
1966           reset after a RESUME operation, the /proc/apm device will provide
1967           battery status information, and user-space programs will receive
1968           notification of APM "events" (e.g. battery status change).
1969 
1970           If you select "Y" here, you can disable actual use of the APM
1971           BIOS by passing the "apm=off" option to the kernel at boot time.
1972 
1973           Note that the APM support is almost completely disabled for
1974           machines with more than one CPU.
1975 
1976           In order to use APM, you will need supporting software. For location
1977           and more information, read <file:Documentation/power/apm-acpi.txt>
1978           and the Battery Powered Linux mini-HOWTO, available from
1979           <http://www.tldp.org/docs.html#howto>.
1980 
1981           This driver does not spin down disk drives (see the hdparm(8)
1982           manpage ("man 8 hdparm") for that), and it doesn't turn off
1983           VESA-compliant "green" monitors.
1984 
1985           This driver does not support the TI 4000M TravelMate and the ACER
1986           486/DX4/75 because they don't have compliant BIOSes. Many "green"
1987           desktop machines also don't have compliant BIOSes, and this driver
1988           may cause those machines to panic during the boot phase.
1989 
1990           Generally, if you don't have a battery in your machine, there isn't
1991           much point in using this driver and you should say N. If you get
1992           random kernel OOPSes or reboots that don't seem to be related to
1993           anything, try disabling/enabling this option (or disabling/enabling
1994           APM in your BIOS).
1995 
1996           Some other things you should try when experiencing seemingly random,
1997           "weird" problems:
1998 
1999           1) make sure that you have enough swap space and that it is
2000           enabled.
2001           2) pass the "no-hlt" option to the kernel
2002           3) switch on floating point emulation in the kernel and pass
2003           the "no387" option to the kernel
2004           4) pass the "floppy=nodma" option to the kernel
2005           5) pass the "mem=4M" option to the kernel (thereby disabling
2006           all but the first 4 MB of RAM)
2007           6) make sure that the CPU is not over clocked.
2008           7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2009           8) disable the cache from your BIOS settings
2010           9) install a fan for the video card or exchange video RAM
2011           10) install a better fan for the CPU
2012           11) exchange RAM chips
2013           12) exchange the motherboard.
2014 
2015           To compile this driver as a module, choose M here: the
2016           module will be called apm.
2017 
2018 if APM
2019 
2020 config APM_IGNORE_USER_SUSPEND
2021         bool "Ignore USER SUSPEND"
2022         ---help---
2023           This option will ignore USER SUSPEND requests. On machines with a
2024           compliant APM BIOS, you want to say N. However, on the NEC Versa M
2025           series notebooks, it is necessary to say Y because of a BIOS bug.
2026 
2027 config APM_DO_ENABLE
2028         bool "Enable PM at boot time"
2029         ---help---
2030           Enable APM features at boot time. From page 36 of the APM BIOS
2031           specification: "When disabled, the APM BIOS does not automatically
2032           power manage devices, enter the Standby State, enter the Suspend
2033           State, or take power saving steps in response to CPU Idle calls."
2034           This driver will make CPU Idle calls when Linux is idle (unless this
2035           feature is turned off -- see "Do CPU IDLE calls", below). This
2036           should always save battery power, but more complicated APM features
2037           will be dependent on your BIOS implementation. You may need to turn
2038           this option off if your computer hangs at boot time when using APM
2039           support, or if it beeps continuously instead of suspending. Turn
2040           this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2041           T400CDT. This is off by default since most machines do fine without
2042           this feature.
2043 
2044 config APM_CPU_IDLE
2045         depends on CPU_IDLE
2046         bool "Make CPU Idle calls when idle"
2047         ---help---
2048           Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2049           On some machines, this can activate improved power savings, such as
2050           a slowed CPU clock rate, when the machine is idle. These idle calls
2051           are made after the idle loop has run for some length of time (e.g.,
2052           333 mS). On some machines, this will cause a hang at boot time or
2053           whenever the CPU becomes idle. (On machines with more than one CPU,
2054           this option does nothing.)
2055 
2056 config APM_DISPLAY_BLANK
2057         bool "Enable console blanking using APM"
2058         ---help---
2059           Enable console blanking using the APM. Some laptops can use this to
2060           turn off the LCD backlight when the screen blanker of the Linux
2061           virtual console blanks the screen. Note that this is only used by
2062           the virtual console screen blanker, and won't turn off the backlight
2063           when using the X Window system. This also doesn't have anything to
2064           do with your VESA-compliant power-saving monitor. Further, this
2065           option doesn't work for all laptops -- it might not turn off your
2066           backlight at all, or it might print a lot of errors to the console,
2067           especially if you are using gpm.
2068 
2069 config APM_ALLOW_INTS
2070         bool "Allow interrupts during APM BIOS calls"
2071         ---help---
2072           Normally we disable external interrupts while we are making calls to
2073           the APM BIOS as a measure to lessen the effects of a badly behaving
2074           BIOS implementation.  The BIOS should reenable interrupts if it
2075           needs to.  Unfortunately, some BIOSes do not -- especially those in
2076           many of the newer IBM Thinkpads.  If you experience hangs when you
2077           suspend, try setting this to Y.  Otherwise, say N.
2078 
2079 endif # APM
2080 
2081 source "drivers/cpufreq/Kconfig"
2082 
2083 source "drivers/cpuidle/Kconfig"
2084 
2085 source "drivers/idle/Kconfig"
2086 
2087 endmenu
2088 
2089 
2090 menu "Bus options (PCI etc.)"
2091 
2092 config PCI
2093         bool "PCI support"
2094         default y
2095         ---help---
2096           Find out whether you have a PCI motherboard. PCI is the name of a
2097           bus system, i.e. the way the CPU talks to the other stuff inside
2098           your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2099           VESA. If you have PCI, say Y, otherwise N.
2100 
2101 choice
2102         prompt "PCI access mode"
2103         depends on X86_32 && PCI
2104         default PCI_GOANY
2105         ---help---
2106           On PCI systems, the BIOS can be used to detect the PCI devices and
2107           determine their configuration. However, some old PCI motherboards
2108           have BIOS bugs and may crash if this is done. Also, some embedded
2109           PCI-based systems don't have any BIOS at all. Linux can also try to
2110           detect the PCI hardware directly without using the BIOS.
2111 
2112           With this option, you can specify how Linux should detect the
2113           PCI devices. If you choose "BIOS", the BIOS will be used,
2114           if you choose "Direct", the BIOS won't be used, and if you
2115           choose "MMConfig", then PCI Express MMCONFIG will be used.
2116           If you choose "Any", the kernel will try MMCONFIG, then the
2117           direct access method and falls back to the BIOS if that doesn't
2118           work. If unsure, go with the default, which is "Any".
2119 
2120 config PCI_GOBIOS
2121         bool "BIOS"
2122 
2123 config PCI_GOMMCONFIG
2124         bool "MMConfig"
2125 
2126 config PCI_GODIRECT
2127         bool "Direct"
2128 
2129 config PCI_GOOLPC
2130         bool "OLPC XO-1"
2131         depends on OLPC
2132 
2133 config PCI_GOANY
2134         bool "Any"
2135 
2136 endchoice
2137 
2138 config PCI_BIOS
2139         def_bool y
2140         depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2141 
2142 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2143 config PCI_DIRECT
2144         def_bool y
2145         depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2146 
2147 config PCI_MMCONFIG
2148         def_bool y
2149         depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2150 
2151 config PCI_OLPC
2152         def_bool y
2153         depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2154 
2155 config PCI_XEN
2156         def_bool y
2157         depends on PCI && XEN
2158         select SWIOTLB_XEN
2159 
2160 config PCI_DOMAINS
2161         def_bool y
2162         depends on PCI
2163 
2164 config PCI_MMCONFIG
2165         bool "Support mmconfig PCI config space access"
2166         depends on X86_64 && PCI && ACPI
2167 
2168 config PCI_CNB20LE_QUIRK
2169         bool "Read CNB20LE Host Bridge Windows" if EXPERT
2170         depends on PCI
2171         help
2172           Read the PCI windows out of the CNB20LE host bridge. This allows
2173           PCI hotplug to work on systems with the CNB20LE chipset which do
2174           not have ACPI.
2175 
2176           There's no public spec for this chipset, and this functionality
2177           is known to be incomplete.
2178 
2179           You should say N unless you know you need this.
2180 
2181 source "drivers/pci/pcie/Kconfig"
2182 
2183 source "drivers/pci/Kconfig"
2184 
2185 # x86_64 have no ISA slots, but can have ISA-style DMA.
2186 config ISA_DMA_API
2187         bool "ISA-style DMA support" if (X86_64 && EXPERT)
2188         default y
2189         help
2190           Enables ISA-style DMA support for devices requiring such controllers.
2191           If unsure, say Y.
2192 
2193 if X86_32
2194 
2195 config ISA
2196         bool "ISA support"
2197         ---help---
2198           Find out whether you have ISA slots on your motherboard.  ISA is the
2199           name of a bus system, i.e. the way the CPU talks to the other stuff
2200           inside your box.  Other bus systems are PCI, EISA, MicroChannel
2201           (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2202           newer boards don't support it.  If you have ISA, say Y, otherwise N.
2203 
2204 config EISA
2205         bool "EISA support"
2206         depends on ISA
2207         ---help---
2208           The Extended Industry Standard Architecture (EISA) bus was
2209           developed as an open alternative to the IBM MicroChannel bus.
2210 
2211           The EISA bus provided some of the features of the IBM MicroChannel
2212           bus while maintaining backward compatibility with cards made for
2213           the older ISA bus.  The EISA bus saw limited use between 1988 and
2214           1995 when it was made obsolete by the PCI bus.
2215 
2216           Say Y here if you are building a kernel for an EISA-based machine.
2217 
2218           Otherwise, say N.
2219 
2220 source "drivers/eisa/Kconfig"
2221 
2222 config SCx200
2223         tristate "NatSemi SCx200 support"
2224         ---help---
2225           This provides basic support for National Semiconductor's
2226           (now AMD's) Geode processors.  The driver probes for the
2227           PCI-IDs of several on-chip devices, so its a good dependency
2228           for other scx200_* drivers.
2229 
2230           If compiled as a module, the driver is named scx200.
2231 
2232 config SCx200HR_TIMER
2233         tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2234         depends on SCx200
2235         default y
2236         ---help---
2237           This driver provides a clocksource built upon the on-chip
2238           27MHz high-resolution timer.  Its also a workaround for
2239           NSC Geode SC-1100's buggy TSC, which loses time when the
2240           processor goes idle (as is done by the scheduler).  The
2241           other workaround is idle=poll boot option.
2242 
2243 config OLPC
2244         bool "One Laptop Per Child support"
2245         depends on !X86_PAE
2246         select GPIOLIB
2247         select OF
2248         select OF_PROMTREE
2249         select IRQ_DOMAIN
2250         ---help---
2251           Add support for detecting the unique features of the OLPC
2252           XO hardware.
2253 
2254 config OLPC_XO1_PM
2255         bool "OLPC XO-1 Power Management"
2256         depends on OLPC && MFD_CS5535 && PM_SLEEP
2257         select MFD_CORE
2258         ---help---
2259           Add support for poweroff and suspend of the OLPC XO-1 laptop.
2260 
2261 config OLPC_XO1_RTC
2262         bool "OLPC XO-1 Real Time Clock"
2263         depends on OLPC_XO1_PM && RTC_DRV_CMOS
2264         ---help---
2265           Add support for the XO-1 real time clock, which can be used as a
2266           programmable wakeup source.
2267 
2268 config OLPC_XO1_SCI
2269         bool "OLPC XO-1 SCI extras"
2270         depends on OLPC && OLPC_XO1_PM
2271         depends on INPUT=y
2272         select POWER_SUPPLY
2273         select GPIO_CS5535
2274         select MFD_CORE
2275         ---help---
2276           Add support for SCI-based features of the OLPC XO-1 laptop:
2277            - EC-driven system wakeups
2278            - Power button
2279            - Ebook switch
2280            - Lid switch
2281            - AC adapter status updates
2282            - Battery status updates
2283 
2284 config OLPC_XO15_SCI
2285         bool "OLPC XO-1.5 SCI extras"
2286         depends on OLPC && ACPI
2287         select POWER_SUPPLY
2288         ---help---
2289           Add support for SCI-based features of the OLPC XO-1.5 laptop:
2290            - EC-driven system wakeups
2291            - AC adapter status updates
2292            - Battery status updates
2293 
2294 config ALIX
2295         bool "PCEngines ALIX System Support (LED setup)"
2296         select GPIOLIB
2297         ---help---
2298           This option enables system support for the PCEngines ALIX.
2299           At present this just sets up LEDs for GPIO control on
2300           ALIX2/3/6 boards.  However, other system specific setup should
2301           get added here.
2302 
2303           Note: You must still enable the drivers for GPIO and LED support
2304           (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2305 
2306           Note: You have to set alix.force=1 for boards with Award BIOS.
2307 
2308 config NET5501
2309         bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2310         select GPIOLIB
2311         ---help---
2312           This option enables system support for the Soekris Engineering net5501.
2313 
2314 config GEOS
2315         bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2316         select GPIOLIB
2317         depends on DMI
2318         ---help---
2319           This option enables system support for the Traverse Technologies GEOS.
2320 
2321 config TS5500
2322         bool "Technologic Systems TS-5500 platform support"
2323         depends on MELAN
2324         select CHECK_SIGNATURE
2325         select NEW_LEDS
2326         select LEDS_CLASS
2327         ---help---
2328           This option enables system support for the Technologic Systems TS-5500.
2329 
2330 endif # X86_32
2331 
2332 config AMD_NB
2333         def_bool y
2334         depends on CPU_SUP_AMD && PCI
2335 
2336 source "drivers/pcmcia/Kconfig"
2337 
2338 source "drivers/pci/hotplug/Kconfig"
2339 
2340 config RAPIDIO
2341         tristate "RapidIO support"
2342         depends on PCI
2343         default n
2344         help
2345           If enabled this option will include drivers and the core
2346           infrastructure code to support RapidIO interconnect devices.
2347 
2348 source "drivers/rapidio/Kconfig"
2349 
2350 config X86_SYSFB
2351         bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2352         help
2353           Firmwares often provide initial graphics framebuffers so the BIOS,
2354           bootloader or kernel can show basic video-output during boot for
2355           user-guidance and debugging. Historically, x86 used the VESA BIOS
2356           Extensions and EFI-framebuffers for this, which are mostly limited
2357           to x86.
2358           This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2359           framebuffers so the new generic system-framebuffer drivers can be
2360           used on x86. If the framebuffer is not compatible with the generic
2361           modes, it is adverticed as fallback platform framebuffer so legacy
2362           drivers like efifb, vesafb and uvesafb can pick it up.
2363           If this option is not selected, all system framebuffers are always
2364           marked as fallback platform framebuffers as usual.
2365 
2366           Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2367           not be able to pick up generic system framebuffers if this option
2368           is selected. You are highly encouraged to enable simplefb as
2369           replacement if you select this option. simplefb can correctly deal
2370           with generic system framebuffers. But you should still keep vesafb
2371           and others enabled as fallback if a system framebuffer is
2372           incompatible with simplefb.
2373 
2374           If unsure, say Y.
2375 
2376 endmenu
2377 
2378 
2379 menu "Executable file formats / Emulations"
2380 
2381 source "fs/Kconfig.binfmt"
2382 
2383 config IA32_EMULATION
2384         bool "IA32 Emulation"
2385         depends on X86_64
2386         select BINFMT_ELF
2387         select COMPAT_BINFMT_ELF
2388         select HAVE_UID16
2389         ---help---
2390           Include code to run legacy 32-bit programs under a
2391           64-bit kernel. You should likely turn this on, unless you're
2392           100% sure that you don't have any 32-bit programs left.
2393 
2394 config IA32_AOUT
2395         tristate "IA32 a.out support"
2396         depends on IA32_EMULATION
2397         ---help---
2398           Support old a.out binaries in the 32bit emulation.
2399 
2400 config X86_X32
2401         bool "x32 ABI for 64-bit mode"
2402         depends on X86_64 && IA32_EMULATION
2403         ---help---
2404           Include code to run binaries for the x32 native 32-bit ABI
2405           for 64-bit processors.  An x32 process gets access to the
2406           full 64-bit register file and wide data path while leaving
2407           pointers at 32 bits for smaller memory footprint.
2408 
2409           You will need a recent binutils (2.22 or later) with
2410           elf32_x86_64 support enabled to compile a kernel with this
2411           option set.
2412 
2413 config COMPAT
2414         def_bool y
2415         depends on IA32_EMULATION || X86_X32
2416         select ARCH_WANT_OLD_COMPAT_IPC
2417 
2418 if COMPAT
2419 config COMPAT_FOR_U64_ALIGNMENT
2420         def_bool y
2421 
2422 config SYSVIPC_COMPAT
2423         def_bool y
2424         depends on SYSVIPC
2425 
2426 config KEYS_COMPAT
2427         def_bool y
2428         depends on KEYS
2429 endif
2430 
2431 endmenu
2432 
2433 
2434 config HAVE_ATOMIC_IOMAP
2435         def_bool y
2436         depends on X86_32
2437 
2438 config X86_DEV_DMA_OPS
2439         bool
2440         depends on X86_64 || STA2X11
2441 
2442 config X86_DMA_REMAP
2443         bool
2444         depends on STA2X11
2445 
2446 config IOSF_MBI
2447         tristate
2448         default m
2449         depends on PCI
2450 
2451 config PMC_ATOM
2452         def_bool y
2453         depends on PCI
2454 
2455 source "net/Kconfig"
2456 
2457 source "drivers/Kconfig"
2458 
2459 source "drivers/firmware/Kconfig"
2460 
2461 source "fs/Kconfig"
2462 
2463 source "arch/x86/Kconfig.debug"
2464 
2465 source "security/Kconfig"
2466 
2467 source "crypto/Kconfig"
2468 
2469 source "arch/x86/kvm/Kconfig"
2470 
2471 source "lib/Kconfig"

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