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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_HAS_DEBUG_STRICT_USER_COPY_CHECKS
 25         select ARCH_MIGHT_HAVE_PC_PARPORT
 26         select ARCH_MIGHT_HAVE_PC_SERIO
 27         select HAVE_AOUT if X86_32
 28         select HAVE_UNSTABLE_SCHED_CLOCK
 29         select ARCH_SUPPORTS_NUMA_BALANCING
 30         select ARCH_SUPPORTS_INT128 if X86_64
 31         select ARCH_WANTS_PROT_NUMA_PROT_NONE
 32         select HAVE_IDE
 33         select HAVE_OPROFILE
 34         select HAVE_PCSPKR_PLATFORM
 35         select HAVE_PERF_EVENTS
 36         select HAVE_IOREMAP_PROT
 37         select HAVE_KPROBES
 38         select HAVE_MEMBLOCK
 39         select HAVE_MEMBLOCK_NODE_MAP
 40         select ARCH_DISCARD_MEMBLOCK
 41         select ARCH_WANT_OPTIONAL_GPIOLIB
 42         select ARCH_WANT_FRAME_POINTERS
 43         select HAVE_DMA_ATTRS
 44         select HAVE_DMA_CONTIGUOUS if !SWIOTLB
 45         select HAVE_KRETPROBES
 46         select HAVE_OPTPROBES
 47         select HAVE_KPROBES_ON_FTRACE
 48         select HAVE_FTRACE_MCOUNT_RECORD
 49         select HAVE_FENTRY if X86_64
 50         select HAVE_C_RECORDMCOUNT
 51         select HAVE_DYNAMIC_FTRACE
 52         select HAVE_DYNAMIC_FTRACE_WITH_REGS
 53         select HAVE_FUNCTION_TRACER
 54         select HAVE_FUNCTION_GRAPH_TRACER
 55         select HAVE_FUNCTION_GRAPH_FP_TEST
 56         select HAVE_FUNCTION_TRACE_MCOUNT_TEST
 57         select HAVE_SYSCALL_TRACEPOINTS
 58         select SYSCTL_EXCEPTION_TRACE
 59         select HAVE_KVM
 60         select HAVE_ARCH_KGDB
 61         select HAVE_ARCH_TRACEHOOK
 62         select HAVE_GENERIC_DMA_COHERENT if X86_32
 63         select HAVE_EFFICIENT_UNALIGNED_ACCESS
 64         select USER_STACKTRACE_SUPPORT
 65         select HAVE_REGS_AND_STACK_ACCESS_API
 66         select HAVE_DMA_API_DEBUG
 67         select HAVE_KERNEL_GZIP
 68         select HAVE_KERNEL_BZIP2
 69         select HAVE_KERNEL_LZMA
 70         select HAVE_KERNEL_XZ
 71         select HAVE_KERNEL_LZO
 72         select HAVE_KERNEL_LZ4
 73         select HAVE_HW_BREAKPOINT
 74         select HAVE_MIXED_BREAKPOINTS_REGS
 75         select PERF_EVENTS
 76         select HAVE_PERF_EVENTS_NMI
 77         select HAVE_PERF_REGS
 78         select HAVE_PERF_USER_STACK_DUMP
 79         select HAVE_DEBUG_KMEMLEAK
 80         select ANON_INODES
 81         select HAVE_ALIGNED_STRUCT_PAGE if SLUB
 82         select HAVE_CMPXCHG_LOCAL
 83         select HAVE_CMPXCHG_DOUBLE
 84         select HAVE_ARCH_KMEMCHECK
 85         select HAVE_USER_RETURN_NOTIFIER
 86         select ARCH_BINFMT_ELF_RANDOMIZE_PIE
 87         select HAVE_ARCH_JUMP_LABEL
 88         select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 89         select SPARSE_IRQ
 90         select GENERIC_FIND_FIRST_BIT
 91         select GENERIC_IRQ_PROBE
 92         select GENERIC_PENDING_IRQ if SMP
 93         select GENERIC_IRQ_SHOW
 94         select GENERIC_CLOCKEVENTS_MIN_ADJUST
 95         select IRQ_FORCED_THREADING
 96         select HAVE_BPF_JIT if X86_64
 97         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 98         select CLKEVT_I8253
 99         select ARCH_HAVE_NMI_SAFE_CMPXCHG
100         select GENERIC_IOMAP
101         select DCACHE_WORD_ACCESS
102         select GENERIC_SMP_IDLE_THREAD
103         select ARCH_WANT_IPC_PARSE_VERSION if X86_32
104         select HAVE_ARCH_SECCOMP_FILTER
105         select BUILDTIME_EXTABLE_SORT
106         select GENERIC_CMOS_UPDATE
107         select HAVE_ARCH_SOFT_DIRTY
108         select CLOCKSOURCE_WATCHDOG
109         select GENERIC_CLOCKEVENTS
110         select ARCH_CLOCKSOURCE_DATA if X86_64
111         select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
112         select GENERIC_TIME_VSYSCALL if X86_64
113         select KTIME_SCALAR if X86_32
114         select GENERIC_STRNCPY_FROM_USER
115         select GENERIC_STRNLEN_USER
116         select HAVE_CONTEXT_TRACKING if X86_64
117         select HAVE_IRQ_TIME_ACCOUNTING
118         select VIRT_TO_BUS
119         select MODULES_USE_ELF_REL if X86_32
120         select MODULES_USE_ELF_RELA if X86_64
121         select CLONE_BACKWARDS if X86_32
122         select ARCH_USE_BUILTIN_BSWAP
123         select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
124         select OLD_SIGACTION if X86_32
125         select COMPAT_OLD_SIGACTION if IA32_EMULATION
126         select RTC_LIB
127         select HAVE_DEBUG_STACKOVERFLOW
128         select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
129         select HAVE_CC_STACKPROTECTOR
130 
131 config INSTRUCTION_DECODER
132         def_bool y
133         depends on KPROBES || PERF_EVENTS || UPROBES
134 
135 config OUTPUT_FORMAT
136         string
137         default "elf32-i386" if X86_32
138         default "elf64-x86-64" if X86_64
139 
140 config ARCH_DEFCONFIG
141         string
142         default "arch/x86/configs/i386_defconfig" if X86_32
143         default "arch/x86/configs/x86_64_defconfig" if X86_64
144 
145 config LOCKDEP_SUPPORT
146         def_bool y
147 
148 config STACKTRACE_SUPPORT
149         def_bool y
150 
151 config HAVE_LATENCYTOP_SUPPORT
152         def_bool y
153 
154 config MMU
155         def_bool y
156 
157 config SBUS
158         bool
159 
160 config NEED_DMA_MAP_STATE
161         def_bool y
162         depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
163 
164 config NEED_SG_DMA_LENGTH
165         def_bool y
166 
167 config GENERIC_ISA_DMA
168         def_bool y
169         depends on ISA_DMA_API
170 
171 config GENERIC_BUG
172         def_bool y
173         depends on BUG
174         select GENERIC_BUG_RELATIVE_POINTERS if X86_64
175 
176 config GENERIC_BUG_RELATIVE_POINTERS
177         bool
178 
179 config GENERIC_HWEIGHT
180         def_bool y
181 
182 config ARCH_MAY_HAVE_PC_FDC
183         def_bool y
184         depends on ISA_DMA_API
185 
186 config RWSEM_XCHGADD_ALGORITHM
187         def_bool y
188 
189 config GENERIC_CALIBRATE_DELAY
190         def_bool y
191 
192 config ARCH_HAS_CPU_RELAX
193         def_bool y
194 
195 config ARCH_HAS_CACHE_LINE_SIZE
196         def_bool y
197 
198 config ARCH_HAS_CPU_AUTOPROBE
199         def_bool y
200 
201 config HAVE_SETUP_PER_CPU_AREA
202         def_bool y
203 
204 config NEED_PER_CPU_EMBED_FIRST_CHUNK
205         def_bool y
206 
207 config NEED_PER_CPU_PAGE_FIRST_CHUNK
208         def_bool y
209 
210 config ARCH_HIBERNATION_POSSIBLE
211         def_bool y
212 
213 config ARCH_SUSPEND_POSSIBLE
214         def_bool y
215 
216 config ARCH_WANT_HUGE_PMD_SHARE
217         def_bool y
218 
219 config ARCH_WANT_GENERAL_HUGETLB
220         def_bool y
221 
222 config ZONE_DMA32
223         bool
224         default X86_64
225 
226 config AUDIT_ARCH
227         bool
228         default X86_64
229 
230 config ARCH_SUPPORTS_OPTIMIZED_INLINING
231         def_bool y
232 
233 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
234         def_bool y
235 
236 config HAVE_INTEL_TXT
237         def_bool y
238         depends on INTEL_IOMMU && ACPI
239 
240 config X86_32_SMP
241         def_bool y
242         depends on X86_32 && SMP
243 
244 config X86_64_SMP
245         def_bool y
246         depends on X86_64 && SMP
247 
248 config X86_HT
249         def_bool y
250         depends on SMP
251 
252 config X86_32_LAZY_GS
253         def_bool y
254         depends on X86_32 && !CC_STACKPROTECTOR
255 
256 config ARCH_HWEIGHT_CFLAGS
257         string
258         default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
259         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
260 
261 config ARCH_SUPPORTS_UPROBES
262         def_bool y
263 
264 source "init/Kconfig"
265 source "kernel/Kconfig.freezer"
266 
267 menu "Processor type and features"
268 
269 config ZONE_DMA
270         bool "DMA memory allocation support" if EXPERT
271         default y
272         help
273           DMA memory allocation support allows devices with less than 32-bit
274           addressing to allocate within the first 16MB of address space.
275           Disable if no such devices will be used.
276 
277           If unsure, say Y.
278 
279 config SMP
280         bool "Symmetric multi-processing support"
281         ---help---
282           This enables support for systems with more than one CPU. If you have
283           a system with only one CPU, say N. If you have a system with more
284           than one CPU, say Y.
285 
286           If you say N here, the kernel will run on uni- and multiprocessor
287           machines, but will use only one CPU of a multiprocessor machine. If
288           you say Y here, the kernel will run on many, but not all,
289           uniprocessor machines. On a uniprocessor machine, the kernel
290           will run faster if you say N here.
291 
292           Note that if you say Y here and choose architecture "586" or
293           "Pentium" under "Processor family", the kernel will not work on 486
294           architectures. Similarly, multiprocessor kernels for the "PPro"
295           architecture may not work on all Pentium based boards.
296 
297           People using multiprocessor machines who say Y here should also say
298           Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
299           Management" code will be disabled if you say Y here.
300 
301           See also <file:Documentation/x86/i386/IO-APIC.txt>,
302           <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
303           <http://www.tldp.org/docs.html#howto>.
304 
305           If you don't know what to do here, say N.
306 
307 config X86_X2APIC
308         bool "Support x2apic"
309         depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
310         ---help---
311           This enables x2apic support on CPUs that have this feature.
312 
313           This allows 32-bit apic IDs (so it can support very large systems),
314           and accesses the local apic via MSRs not via mmio.
315 
316           If you don't know what to do here, say N.
317 
318 config X86_MPPARSE
319         bool "Enable MPS table" if ACPI || SFI
320         default y
321         depends on X86_LOCAL_APIC
322         ---help---
323           For old smp systems that do not have proper acpi support. Newer systems
324           (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
325 
326 config X86_BIGSMP
327         bool "Support for big SMP systems with more than 8 CPUs"
328         depends on X86_32 && SMP
329         ---help---
330           This option is needed for the systems that have more than 8 CPUs
331 
332 config GOLDFISH
333        def_bool y
334        depends on X86_GOLDFISH
335 
336 if X86_32
337 config X86_EXTENDED_PLATFORM
338         bool "Support for extended (non-PC) x86 platforms"
339         default y
340         ---help---
341           If you disable this option then the kernel will only support
342           standard PC platforms. (which covers the vast majority of
343           systems out there.)
344 
345           If you enable this option then you'll be able to select support
346           for the following (non-PC) 32 bit x86 platforms:
347                 Goldfish (Android emulator)
348                 AMD Elan
349                 NUMAQ (IBM/Sequent)
350                 RDC R-321x SoC
351                 SGI 320/540 (Visual Workstation)
352                 STA2X11-based (e.g. Northville)
353                 Summit/EXA (IBM x440)
354                 Unisys ES7000 IA32 series
355                 Moorestown MID devices
356 
357           If you have one of these systems, or if you want to build a
358           generic distribution kernel, say Y here - otherwise say N.
359 endif
360 
361 if X86_64
362 config X86_EXTENDED_PLATFORM
363         bool "Support for extended (non-PC) x86 platforms"
364         default y
365         ---help---
366           If you disable this option then the kernel will only support
367           standard PC platforms. (which covers the vast majority of
368           systems out there.)
369 
370           If you enable this option then you'll be able to select support
371           for the following (non-PC) 64 bit x86 platforms:
372                 Numascale NumaChip
373                 ScaleMP vSMP
374                 SGI Ultraviolet
375 
376           If you have one of these systems, or if you want to build a
377           generic distribution kernel, say Y here - otherwise say N.
378 endif
379 # This is an alphabetically sorted list of 64 bit extended platforms
380 # Please maintain the alphabetic order if and when there are additions
381 config X86_NUMACHIP
382         bool "Numascale NumaChip"
383         depends on X86_64
384         depends on X86_EXTENDED_PLATFORM
385         depends on NUMA
386         depends on SMP
387         depends on X86_X2APIC
388         depends on PCI_MMCONFIG
389         ---help---
390           Adds support for Numascale NumaChip large-SMP systems. Needed to
391           enable more than ~168 cores.
392           If you don't have one of these, you should say N here.
393 
394 config X86_VSMP
395         bool "ScaleMP vSMP"
396         select HYPERVISOR_GUEST
397         select PARAVIRT
398         depends on X86_64 && PCI
399         depends on X86_EXTENDED_PLATFORM
400         depends on SMP
401         ---help---
402           Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
403           supposed to run on these EM64T-based machines.  Only choose this option
404           if you have one of these machines.
405 
406 config X86_UV
407         bool "SGI Ultraviolet"
408         depends on X86_64
409         depends on X86_EXTENDED_PLATFORM
410         depends on NUMA
411         depends on X86_X2APIC
412         ---help---
413           This option is needed in order to support SGI Ultraviolet systems.
414           If you don't have one of these, you should say N here.
415 
416 # Following is an alphabetically sorted list of 32 bit extended platforms
417 # Please maintain the alphabetic order if and when there are additions
418 
419 config X86_GOLDFISH
420        bool "Goldfish (Virtual Platform)"
421        depends on X86_32
422        depends on X86_EXTENDED_PLATFORM
423        ---help---
424          Enable support for the Goldfish virtual platform used primarily
425          for Android development. Unless you are building for the Android
426          Goldfish emulator say N here.
427 
428 config X86_INTEL_CE
429         bool "CE4100 TV platform"
430         depends on PCI
431         depends on PCI_GODIRECT
432         depends on X86_32
433         depends on X86_EXTENDED_PLATFORM
434         select X86_REBOOTFIXUPS
435         select OF
436         select OF_EARLY_FLATTREE
437         select IRQ_DOMAIN
438         ---help---
439           Select for the Intel CE media processor (CE4100) SOC.
440           This option compiles in support for the CE4100 SOC for settop
441           boxes and media devices.
442 
443 config X86_INTEL_MID
444         bool "Intel MID platform support"
445         depends on X86_32
446         depends on X86_EXTENDED_PLATFORM
447         depends on X86_PLATFORM_DEVICES
448         depends on PCI
449         depends on PCI_GOANY
450         depends on X86_IO_APIC
451         select SFI
452         select I2C
453         select DW_APB_TIMER
454         select APB_TIMER
455         select INTEL_SCU_IPC
456         select MFD_INTEL_MSIC
457         ---help---
458           Select to build a kernel capable of supporting Intel MID (Mobile
459           Internet Device) platform systems which do not have the PCI legacy
460           interfaces. If you are building for a PC class system say N here.
461 
462           Intel MID platforms are based on an Intel processor and chipset which
463           consume less power than most of the x86 derivatives.
464 
465 config X86_INTEL_LPSS
466         bool "Intel Low Power Subsystem Support"
467         depends on ACPI
468         select COMMON_CLK
469         select PINCTRL
470         ---help---
471           Select to build support for Intel Low Power Subsystem such as
472           found on Intel Lynxpoint PCH. Selecting this option enables
473           things like clock tree (common clock framework) and pincontrol
474           which are needed by the LPSS peripheral drivers.
475 
476 config X86_RDC321X
477         bool "RDC R-321x SoC"
478         depends on X86_32
479         depends on X86_EXTENDED_PLATFORM
480         select M486
481         select X86_REBOOTFIXUPS
482         ---help---
483           This option is needed for RDC R-321x system-on-chip, also known
484           as R-8610-(G).
485           If you don't have one of these chips, you should say N here.
486 
487 config X86_32_NON_STANDARD
488         bool "Support non-standard 32-bit SMP architectures"
489         depends on X86_32 && SMP
490         depends on X86_EXTENDED_PLATFORM
491         ---help---
492           This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
493           STA2X11, default subarchitectures.  It is intended for a generic
494           binary kernel. If you select them all, kernel will probe it
495           one by one and will fallback to default.
496 
497 # Alphabetically sorted list of Non standard 32 bit platforms
498 
499 config X86_NUMAQ
500         bool "NUMAQ (IBM/Sequent)"
501         depends on X86_32_NON_STANDARD
502         depends on PCI
503         select NUMA
504         select X86_MPPARSE
505         ---help---
506           This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
507           NUMA multiquad box. This changes the way that processors are
508           bootstrapped, and uses Clustered Logical APIC addressing mode instead
509           of Flat Logical.  You will need a new lynxer.elf file to flash your
510           firmware with - send email to <Martin.Bligh@us.ibm.com>.
511 
512 config X86_SUPPORTS_MEMORY_FAILURE
513         def_bool y
514         # MCE code calls memory_failure():
515         depends on X86_MCE
516         # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
517         depends on !X86_NUMAQ
518         # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
519         depends on X86_64 || !SPARSEMEM
520         select ARCH_SUPPORTS_MEMORY_FAILURE
521 
522 config X86_VISWS
523         bool "SGI 320/540 (Visual Workstation)"
524         depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
525         depends on X86_32_NON_STANDARD
526         ---help---
527           The SGI Visual Workstation series is an IA32-based workstation
528           based on SGI systems chips with some legacy PC hardware attached.
529 
530           Say Y here to create a kernel to run on the SGI 320 or 540.
531 
532           A kernel compiled for the Visual Workstation will run on general
533           PCs as well. See <file:Documentation/sgi-visws.txt> for details.
534 
535 config STA2X11
536         bool "STA2X11 Companion Chip Support"
537         depends on X86_32_NON_STANDARD && PCI
538         select X86_DEV_DMA_OPS
539         select X86_DMA_REMAP
540         select SWIOTLB
541         select MFD_STA2X11
542         select ARCH_REQUIRE_GPIOLIB
543         default n
544         ---help---
545           This adds support for boards based on the STA2X11 IO-Hub,
546           a.k.a. "ConneXt". The chip is used in place of the standard
547           PC chipset, so all "standard" peripherals are missing. If this
548           option is selected the kernel will still be able to boot on
549           standard PC machines.
550 
551 config X86_SUMMIT
552         bool "Summit/EXA (IBM x440)"
553         depends on X86_32_NON_STANDARD
554         ---help---
555           This option is needed for IBM systems that use the Summit/EXA chipset.
556           In particular, it is needed for the x440.
557 
558 config X86_ES7000
559         bool "Unisys ES7000 IA32 series"
560         depends on X86_32_NON_STANDARD && X86_BIGSMP
561         ---help---
562           Support for Unisys ES7000 systems.  Say 'Y' here if this kernel is
563           supposed to run on an IA32-based Unisys ES7000 system.
564 
565 config X86_32_IRIS
566         tristate "Eurobraille/Iris poweroff module"
567         depends on X86_32
568         ---help---
569           The Iris machines from EuroBraille do not have APM or ACPI support
570           to shut themselves down properly.  A special I/O sequence is
571           needed to do so, which is what this module does at
572           kernel shutdown.
573 
574           This is only for Iris machines from EuroBraille.
575 
576           If unused, say N.
577 
578 config SCHED_OMIT_FRAME_POINTER
579         def_bool y
580         prompt "Single-depth WCHAN output"
581         depends on X86
582         ---help---
583           Calculate simpler /proc/<PID>/wchan values. If this option
584           is disabled then wchan values will recurse back to the
585           caller function. This provides more accurate wchan values,
586           at the expense of slightly more scheduling overhead.
587 
588           If in doubt, say "Y".
589 
590 menuconfig HYPERVISOR_GUEST
591         bool "Linux guest support"
592         ---help---
593           Say Y here to enable options for running Linux under various hyper-
594           visors. This option enables basic hypervisor detection and platform
595           setup.
596 
597           If you say N, all options in this submenu will be skipped and
598           disabled, and Linux guest support won't be built in.
599 
600 if HYPERVISOR_GUEST
601 
602 config PARAVIRT
603         bool "Enable paravirtualization code"
604         ---help---
605           This changes the kernel so it can modify itself when it is run
606           under a hypervisor, potentially improving performance significantly
607           over full virtualization.  However, when run without a hypervisor
608           the kernel is theoretically slower and slightly larger.
609 
610 config PARAVIRT_DEBUG
611         bool "paravirt-ops debugging"
612         depends on PARAVIRT && DEBUG_KERNEL
613         ---help---
614           Enable to debug paravirt_ops internals.  Specifically, BUG if
615           a paravirt_op is missing when it is called.
616 
617 config PARAVIRT_SPINLOCKS
618         bool "Paravirtualization layer for spinlocks"
619         depends on PARAVIRT && SMP
620         select UNINLINE_SPIN_UNLOCK
621         ---help---
622           Paravirtualized spinlocks allow a pvops backend to replace the
623           spinlock implementation with something virtualization-friendly
624           (for example, block the virtual CPU rather than spinning).
625 
626           It has a minimal impact on native kernels and gives a nice performance
627           benefit on paravirtualized KVM / Xen kernels.
628 
629           If you are unsure how to answer this question, answer Y.
630 
631 source "arch/x86/xen/Kconfig"
632 
633 config KVM_GUEST
634         bool "KVM Guest support (including kvmclock)"
635         depends on PARAVIRT
636         select PARAVIRT_CLOCK
637         default y
638         ---help---
639           This option enables various optimizations for running under the KVM
640           hypervisor. It includes a paravirtualized clock, so that instead
641           of relying on a PIT (or probably other) emulation by the
642           underlying device model, the host provides the guest with
643           timing infrastructure such as time of day, and system time
644 
645 config KVM_DEBUG_FS
646         bool "Enable debug information for KVM Guests in debugfs"
647         depends on KVM_GUEST && DEBUG_FS
648         default n
649         ---help---
650           This option enables collection of various statistics for KVM guest.
651           Statistics are displayed in debugfs filesystem. Enabling this option
652           may incur significant overhead.
653 
654 source "arch/x86/lguest/Kconfig"
655 
656 config PARAVIRT_TIME_ACCOUNTING
657         bool "Paravirtual steal time accounting"
658         depends on PARAVIRT
659         default n
660         ---help---
661           Select this option to enable fine granularity task steal time
662           accounting. Time spent executing other tasks in parallel with
663           the current vCPU is discounted from the vCPU power. To account for
664           that, there can be a small performance impact.
665 
666           If in doubt, say N here.
667 
668 config PARAVIRT_CLOCK
669         bool
670 
671 endif #HYPERVISOR_GUEST
672 
673 config NO_BOOTMEM
674         def_bool y
675 
676 config MEMTEST
677         bool "Memtest"
678         ---help---
679           This option adds a kernel parameter 'memtest', which allows memtest
680           to be set.
681                 memtest=0, mean disabled; -- default
682                 memtest=1, mean do 1 test pattern;
683                 ...
684                 memtest=4, mean do 4 test patterns.
685           If you are unsure how to answer this question, answer N.
686 
687 config X86_SUMMIT_NUMA
688         def_bool y
689         depends on X86_32 && NUMA && X86_32_NON_STANDARD
690 
691 config X86_CYCLONE_TIMER
692         def_bool y
693         depends on X86_SUMMIT
694 
695 source "arch/x86/Kconfig.cpu"
696 
697 config HPET_TIMER
698         def_bool X86_64
699         prompt "HPET Timer Support" if X86_32
700         ---help---
701           Use the IA-PC HPET (High Precision Event Timer) to manage
702           time in preference to the PIT and RTC, if a HPET is
703           present.
704           HPET is the next generation timer replacing legacy 8254s.
705           The HPET provides a stable time base on SMP
706           systems, unlike the TSC, but it is more expensive to access,
707           as it is off-chip.  You can find the HPET spec at
708           <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
709 
710           You can safely choose Y here.  However, HPET will only be
711           activated if the platform and the BIOS support this feature.
712           Otherwise the 8254 will be used for timing services.
713 
714           Choose N to continue using the legacy 8254 timer.
715 
716 config HPET_EMULATE_RTC
717         def_bool y
718         depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
719 
720 config APB_TIMER
721        def_bool y if X86_INTEL_MID
722        prompt "Intel MID APB Timer Support" if X86_INTEL_MID
723        select DW_APB_TIMER
724        depends on X86_INTEL_MID && SFI
725        help
726          APB timer is the replacement for 8254, HPET on X86 MID platforms.
727          The APBT provides a stable time base on SMP
728          systems, unlike the TSC, but it is more expensive to access,
729          as it is off-chip. APB timers are always running regardless of CPU
730          C states, they are used as per CPU clockevent device when possible.
731 
732 # Mark as expert because too many people got it wrong.
733 # The code disables itself when not needed.
734 config DMI
735         default y
736         select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
737         bool "Enable DMI scanning" if EXPERT
738         ---help---
739           Enabled scanning of DMI to identify machine quirks. Say Y
740           here unless you have verified that your setup is not
741           affected by entries in the DMI blacklist. Required by PNP
742           BIOS code.
743 
744 config GART_IOMMU
745         bool "Old AMD GART IOMMU support"
746         select SWIOTLB
747         depends on X86_64 && PCI && AMD_NB
748         ---help---
749           Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
750           GART based hardware IOMMUs.
751 
752           The GART supports full DMA access for devices with 32-bit access
753           limitations, on systems with more than 3 GB. This is usually needed
754           for USB, sound, many IDE/SATA chipsets and some other devices.
755 
756           Newer systems typically have a modern AMD IOMMU, supported via
757           the CONFIG_AMD_IOMMU=y config option.
758 
759           In normal configurations this driver is only active when needed:
760           there's more than 3 GB of memory and the system contains a
761           32-bit limited device.
762 
763           If unsure, say Y.
764 
765 config CALGARY_IOMMU
766         bool "IBM Calgary IOMMU support"
767         select SWIOTLB
768         depends on X86_64 && PCI
769         ---help---
770           Support for hardware IOMMUs in IBM's xSeries x366 and x460
771           systems. Needed to run systems with more than 3GB of memory
772           properly with 32-bit PCI devices that do not support DAC
773           (Double Address Cycle). Calgary also supports bus level
774           isolation, where all DMAs pass through the IOMMU.  This
775           prevents them from going anywhere except their intended
776           destination. This catches hard-to-find kernel bugs and
777           mis-behaving drivers and devices that do not use the DMA-API
778           properly to set up their DMA buffers.  The IOMMU can be
779           turned off at boot time with the iommu=off parameter.
780           Normally the kernel will make the right choice by itself.
781           If unsure, say Y.
782 
783 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
784         def_bool y
785         prompt "Should Calgary be enabled by default?"
786         depends on CALGARY_IOMMU
787         ---help---
788           Should Calgary be enabled by default? if you choose 'y', Calgary
789           will be used (if it exists). If you choose 'n', Calgary will not be
790           used even if it exists. If you choose 'n' and would like to use
791           Calgary anyway, pass 'iommu=calgary' on the kernel command line.
792           If unsure, say Y.
793 
794 # need this always selected by IOMMU for the VIA workaround
795 config SWIOTLB
796         def_bool y if X86_64
797         ---help---
798           Support for software bounce buffers used on x86-64 systems
799           which don't have a hardware IOMMU. Using this PCI devices
800           which can only access 32-bits of memory can be used on systems
801           with more than 3 GB of memory.
802           If unsure, say Y.
803 
804 config IOMMU_HELPER
805         def_bool y
806         depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
807 
808 config MAXSMP
809         bool "Enable Maximum number of SMP Processors and NUMA Nodes"
810         depends on X86_64 && SMP && DEBUG_KERNEL
811         select CPUMASK_OFFSTACK
812         ---help---
813           Enable maximum number of CPUS and NUMA Nodes for this architecture.
814           If unsure, say N.
815 
816 config NR_CPUS
817         int "Maximum number of CPUs" if SMP && !MAXSMP
818         range 2 8 if SMP && X86_32 && !X86_BIGSMP
819         range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
820         range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
821         default "1" if !SMP
822         default "8192" if MAXSMP
823         default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
824         default "8" if SMP
825         ---help---
826           This allows you to specify the maximum number of CPUs which this
827           kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
828           supported value is 4096, otherwise the maximum value is 512.  The
829           minimum value which makes sense is 2.
830 
831           This is purely to save memory - each supported CPU adds
832           approximately eight kilobytes to the kernel image.
833 
834 config SCHED_SMT
835         bool "SMT (Hyperthreading) scheduler support"
836         depends on X86_HT
837         ---help---
838           SMT scheduler support improves the CPU scheduler's decision making
839           when dealing with Intel Pentium 4 chips with HyperThreading at a
840           cost of slightly increased overhead in some places. If unsure say
841           N here.
842 
843 config SCHED_MC
844         def_bool y
845         prompt "Multi-core scheduler support"
846         depends on X86_HT
847         ---help---
848           Multi-core scheduler support improves the CPU scheduler's decision
849           making when dealing with multi-core CPU chips at a cost of slightly
850           increased overhead in some places. If unsure say N here.
851 
852 source "kernel/Kconfig.preempt"
853 
854 config X86_UP_APIC
855         bool "Local APIC support on uniprocessors"
856         depends on X86_32 && !SMP && !X86_32_NON_STANDARD && !PCI_MSI
857         ---help---
858           A local APIC (Advanced Programmable Interrupt Controller) is an
859           integrated interrupt controller in the CPU. If you have a single-CPU
860           system which has a processor with a local APIC, you can say Y here to
861           enable and use it. If you say Y here even though your machine doesn't
862           have a local APIC, then the kernel will still run with no slowdown at
863           all. The local APIC supports CPU-generated self-interrupts (timer,
864           performance counters), and the NMI watchdog which detects hard
865           lockups.
866 
867 config X86_UP_IOAPIC
868         bool "IO-APIC support on uniprocessors"
869         depends on X86_UP_APIC
870         ---help---
871           An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
872           SMP-capable replacement for PC-style interrupt controllers. Most
873           SMP systems and many recent uniprocessor systems have one.
874 
875           If you have a single-CPU system with an IO-APIC, you can say Y here
876           to use it. If you say Y here even though your machine doesn't have
877           an IO-APIC, then the kernel will still run with no slowdown at all.
878 
879 config X86_LOCAL_APIC
880         def_bool y
881         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
882 
883 config X86_IO_APIC
884         def_bool y
885         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC || PCI_MSI
886 
887 config X86_VISWS_APIC
888         def_bool y
889         depends on X86_32 && X86_VISWS
890 
891 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
892         bool "Reroute for broken boot IRQs"
893         depends on X86_IO_APIC
894         ---help---
895           This option enables a workaround that fixes a source of
896           spurious interrupts. This is recommended when threaded
897           interrupt handling is used on systems where the generation of
898           superfluous "boot interrupts" cannot be disabled.
899 
900           Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
901           entry in the chipset's IO-APIC is masked (as, e.g. the RT
902           kernel does during interrupt handling). On chipsets where this
903           boot IRQ generation cannot be disabled, this workaround keeps
904           the original IRQ line masked so that only the equivalent "boot
905           IRQ" is delivered to the CPUs. The workaround also tells the
906           kernel to set up the IRQ handler on the boot IRQ line. In this
907           way only one interrupt is delivered to the kernel. Otherwise
908           the spurious second interrupt may cause the kernel to bring
909           down (vital) interrupt lines.
910 
911           Only affects "broken" chipsets. Interrupt sharing may be
912           increased on these systems.
913 
914 config X86_MCE
915         bool "Machine Check / overheating reporting"
916         default y
917         ---help---
918           Machine Check support allows the processor to notify the
919           kernel if it detects a problem (e.g. overheating, data corruption).
920           The action the kernel takes depends on the severity of the problem,
921           ranging from warning messages to halting the machine.
922 
923 config X86_MCE_INTEL
924         def_bool y
925         prompt "Intel MCE features"
926         depends on X86_MCE && X86_LOCAL_APIC
927         ---help---
928            Additional support for intel specific MCE features such as
929            the thermal monitor.
930 
931 config X86_MCE_AMD
932         def_bool y
933         prompt "AMD MCE features"
934         depends on X86_MCE && X86_LOCAL_APIC
935         ---help---
936            Additional support for AMD specific MCE features such as
937            the DRAM Error Threshold.
938 
939 config X86_ANCIENT_MCE
940         bool "Support for old Pentium 5 / WinChip machine checks"
941         depends on X86_32 && X86_MCE
942         ---help---
943           Include support for machine check handling on old Pentium 5 or WinChip
944           systems. These typically need to be enabled explicitly on the command
945           line.
946 
947 config X86_MCE_THRESHOLD
948         depends on X86_MCE_AMD || X86_MCE_INTEL
949         def_bool y
950 
951 config X86_MCE_INJECT
952         depends on X86_MCE
953         tristate "Machine check injector support"
954         ---help---
955           Provide support for injecting machine checks for testing purposes.
956           If you don't know what a machine check is and you don't do kernel
957           QA it is safe to say n.
958 
959 config X86_THERMAL_VECTOR
960         def_bool y
961         depends on X86_MCE_INTEL
962 
963 config VM86
964         bool "Enable VM86 support" if EXPERT
965         default y
966         depends on X86_32
967         ---help---
968           This option is required by programs like DOSEMU to run 16-bit legacy
969           code on X86 processors. It also may be needed by software like
970           XFree86 to initialize some video cards via BIOS. Disabling this
971           option saves about 6k.
972 
973 config TOSHIBA
974         tristate "Toshiba Laptop support"
975         depends on X86_32
976         ---help---
977           This adds a driver to safely access the System Management Mode of
978           the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
979           not work on models with a Phoenix BIOS. The System Management Mode
980           is used to set the BIOS and power saving options on Toshiba portables.
981 
982           For information on utilities to make use of this driver see the
983           Toshiba Linux utilities web site at:
984           <http://www.buzzard.org.uk/toshiba/>.
985 
986           Say Y if you intend to run this kernel on a Toshiba portable.
987           Say N otherwise.
988 
989 config I8K
990         tristate "Dell laptop support"
991         select HWMON
992         ---help---
993           This adds a driver to safely access the System Management Mode
994           of the CPU on the Dell Inspiron 8000. The System Management Mode
995           is used to read cpu temperature and cooling fan status and to
996           control the fans on the I8K portables.
997 
998           This driver has been tested only on the Inspiron 8000 but it may
999           also work with other Dell laptops. You can force loading on other
1000           models by passing the parameter `force=1' to the module. Use at
1001           your own risk.
1002 
1003           For information on utilities to make use of this driver see the
1004           I8K Linux utilities web site at:
1005           <http://people.debian.org/~dz/i8k/>
1006 
1007           Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1008           Say N otherwise.
1009 
1010 config X86_REBOOTFIXUPS
1011         bool "Enable X86 board specific fixups for reboot"
1012         depends on X86_32
1013         ---help---
1014           This enables chipset and/or board specific fixups to be done
1015           in order to get reboot to work correctly. This is only needed on
1016           some combinations of hardware and BIOS. The symptom, for which
1017           this config is intended, is when reboot ends with a stalled/hung
1018           system.
1019 
1020           Currently, the only fixup is for the Geode machines using
1021           CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1022 
1023           Say Y if you want to enable the fixup. Currently, it's safe to
1024           enable this option even if you don't need it.
1025           Say N otherwise.
1026 
1027 config MICROCODE
1028         tristate "CPU microcode loading support"
1029         depends on CPU_SUP_AMD || CPU_SUP_INTEL
1030         select FW_LOADER
1031         ---help---
1032 
1033           If you say Y here, you will be able to update the microcode on
1034           certain Intel and AMD processors. The Intel support is for the
1035           IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1036           Xeon etc. The AMD support is for families 0x10 and later. You will
1037           obviously need the actual microcode binary data itself which is not
1038           shipped with the Linux kernel.
1039 
1040           This option selects the general module only, you need to select
1041           at least one vendor specific module as well.
1042 
1043           To compile this driver as a module, choose M here: the module
1044           will be called microcode.
1045 
1046 config MICROCODE_INTEL
1047         bool "Intel microcode loading support"
1048         depends on MICROCODE
1049         default MICROCODE
1050         select FW_LOADER
1051         ---help---
1052           This options enables microcode patch loading support for Intel
1053           processors.
1054 
1055           For the current Intel microcode data package go to
1056           <https://downloadcenter.intel.com> and search for
1057           'Linux Processor Microcode Data File'.
1058 
1059 config MICROCODE_AMD
1060         bool "AMD microcode loading support"
1061         depends on MICROCODE
1062         select FW_LOADER
1063         ---help---
1064           If you select this option, microcode patch loading support for AMD
1065           processors will be enabled.
1066 
1067 config MICROCODE_OLD_INTERFACE
1068         def_bool y
1069         depends on MICROCODE
1070 
1071 config MICROCODE_INTEL_EARLY
1072         def_bool n
1073 
1074 config MICROCODE_AMD_EARLY
1075         def_bool n
1076 
1077 config MICROCODE_EARLY
1078         bool "Early load microcode"
1079         depends on MICROCODE=y && BLK_DEV_INITRD
1080         select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1081         select MICROCODE_AMD_EARLY if MICROCODE_AMD
1082         default y
1083         help
1084           This option provides functionality to read additional microcode data
1085           at the beginning of initrd image. The data tells kernel to load
1086           microcode to CPU's as early as possible. No functional change if no
1087           microcode data is glued to the initrd, therefore it's safe to say Y.
1088 
1089 config X86_MSR
1090         tristate "/dev/cpu/*/msr - Model-specific register support"
1091         ---help---
1092           This device gives privileged processes access to the x86
1093           Model-Specific Registers (MSRs).  It is a character device with
1094           major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1095           MSR accesses are directed to a specific CPU on multi-processor
1096           systems.
1097 
1098 config X86_CPUID
1099         tristate "/dev/cpu/*/cpuid - CPU information support"
1100         ---help---
1101           This device gives processes access to the x86 CPUID instruction to
1102           be executed on a specific processor.  It is a character device
1103           with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1104           /dev/cpu/31/cpuid.
1105 
1106 choice
1107         prompt "High Memory Support"
1108         default HIGHMEM64G if X86_NUMAQ
1109         default HIGHMEM4G
1110         depends on X86_32
1111 
1112 config NOHIGHMEM
1113         bool "off"
1114         depends on !X86_NUMAQ
1115         ---help---
1116           Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1117           However, the address space of 32-bit x86 processors is only 4
1118           Gigabytes large. That means that, if you have a large amount of
1119           physical memory, not all of it can be "permanently mapped" by the
1120           kernel. The physical memory that's not permanently mapped is called
1121           "high memory".
1122 
1123           If you are compiling a kernel which will never run on a machine with
1124           more than 1 Gigabyte total physical RAM, answer "off" here (default
1125           choice and suitable for most users). This will result in a "3GB/1GB"
1126           split: 3GB are mapped so that each process sees a 3GB virtual memory
1127           space and the remaining part of the 4GB virtual memory space is used
1128           by the kernel to permanently map as much physical memory as
1129           possible.
1130 
1131           If the machine has between 1 and 4 Gigabytes physical RAM, then
1132           answer "4GB" here.
1133 
1134           If more than 4 Gigabytes is used then answer "64GB" here. This
1135           selection turns Intel PAE (Physical Address Extension) mode on.
1136           PAE implements 3-level paging on IA32 processors. PAE is fully
1137           supported by Linux, PAE mode is implemented on all recent Intel
1138           processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1139           then the kernel will not boot on CPUs that don't support PAE!
1140 
1141           The actual amount of total physical memory will either be
1142           auto detected or can be forced by using a kernel command line option
1143           such as "mem=256M". (Try "man bootparam" or see the documentation of
1144           your boot loader (lilo or loadlin) about how to pass options to the
1145           kernel at boot time.)
1146 
1147           If unsure, say "off".
1148 
1149 config HIGHMEM4G
1150         bool "4GB"
1151         depends on !X86_NUMAQ
1152         ---help---
1153           Select this if you have a 32-bit processor and between 1 and 4
1154           gigabytes of physical RAM.
1155 
1156 config HIGHMEM64G
1157         bool "64GB"
1158         depends on !M486
1159         select X86_PAE
1160         ---help---
1161           Select this if you have a 32-bit processor and more than 4
1162           gigabytes of physical RAM.
1163 
1164 endchoice
1165 
1166 choice
1167         prompt "Memory split" if EXPERT
1168         default VMSPLIT_3G
1169         depends on X86_32
1170         ---help---
1171           Select the desired split between kernel and user memory.
1172 
1173           If the address range available to the kernel is less than the
1174           physical memory installed, the remaining memory will be available
1175           as "high memory". Accessing high memory is a little more costly
1176           than low memory, as it needs to be mapped into the kernel first.
1177           Note that increasing the kernel address space limits the range
1178           available to user programs, making the address space there
1179           tighter.  Selecting anything other than the default 3G/1G split
1180           will also likely make your kernel incompatible with binary-only
1181           kernel modules.
1182 
1183           If you are not absolutely sure what you are doing, leave this
1184           option alone!
1185 
1186         config VMSPLIT_3G
1187                 bool "3G/1G user/kernel split"
1188         config VMSPLIT_3G_OPT
1189                 depends on !X86_PAE
1190                 bool "3G/1G user/kernel split (for full 1G low memory)"
1191         config VMSPLIT_2G
1192                 bool "2G/2G user/kernel split"
1193         config VMSPLIT_2G_OPT
1194                 depends on !X86_PAE
1195                 bool "2G/2G user/kernel split (for full 2G low memory)"
1196         config VMSPLIT_1G
1197                 bool "1G/3G user/kernel split"
1198 endchoice
1199 
1200 config PAGE_OFFSET
1201         hex
1202         default 0xB0000000 if VMSPLIT_3G_OPT
1203         default 0x80000000 if VMSPLIT_2G
1204         default 0x78000000 if VMSPLIT_2G_OPT
1205         default 0x40000000 if VMSPLIT_1G
1206         default 0xC0000000
1207         depends on X86_32
1208 
1209 config HIGHMEM
1210         def_bool y
1211         depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1212 
1213 config X86_PAE
1214         bool "PAE (Physical Address Extension) Support"
1215         depends on X86_32 && !HIGHMEM4G
1216         ---help---
1217           PAE is required for NX support, and furthermore enables
1218           larger swapspace support for non-overcommit purposes. It
1219           has the cost of more pagetable lookup overhead, and also
1220           consumes more pagetable space per process.
1221 
1222 config ARCH_PHYS_ADDR_T_64BIT
1223         def_bool y
1224         depends on X86_64 || X86_PAE
1225 
1226 config ARCH_DMA_ADDR_T_64BIT
1227         def_bool y
1228         depends on X86_64 || HIGHMEM64G
1229 
1230 config DIRECT_GBPAGES
1231         bool "Enable 1GB pages for kernel pagetables" if EXPERT
1232         default y
1233         depends on X86_64
1234         ---help---
1235           Allow the kernel linear mapping to use 1GB pages on CPUs that
1236           support it. This can improve the kernel's performance a tiny bit by
1237           reducing TLB pressure. If in doubt, say "Y".
1238 
1239 # Common NUMA Features
1240 config NUMA
1241         bool "Numa Memory Allocation and Scheduler Support"
1242         depends on SMP
1243         depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI))
1244         default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1245         ---help---
1246           Enable NUMA (Non Uniform Memory Access) support.
1247 
1248           The kernel will try to allocate memory used by a CPU on the
1249           local memory controller of the CPU and add some more
1250           NUMA awareness to the kernel.
1251 
1252           For 64-bit this is recommended if the system is Intel Core i7
1253           (or later), AMD Opteron, or EM64T NUMA.
1254 
1255           For 32-bit this is only needed on (rare) 32-bit-only platforms
1256           that support NUMA topologies, such as NUMAQ / Summit, or if you
1257           boot a 32-bit kernel on a 64-bit NUMA platform.
1258 
1259           Otherwise, you should say N.
1260 
1261 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1262         depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1263 
1264 config AMD_NUMA
1265         def_bool y
1266         prompt "Old style AMD Opteron NUMA detection"
1267         depends on X86_64 && NUMA && PCI
1268         ---help---
1269           Enable AMD NUMA node topology detection.  You should say Y here if
1270           you have a multi processor AMD system. This uses an old method to
1271           read the NUMA configuration directly from the builtin Northbridge
1272           of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1273           which also takes priority if both are compiled in.
1274 
1275 config X86_64_ACPI_NUMA
1276         def_bool y
1277         prompt "ACPI NUMA detection"
1278         depends on X86_64 && NUMA && ACPI && PCI
1279         select ACPI_NUMA
1280         ---help---
1281           Enable ACPI SRAT based node topology detection.
1282 
1283 # Some NUMA nodes have memory ranges that span
1284 # other nodes.  Even though a pfn is valid and
1285 # between a node's start and end pfns, it may not
1286 # reside on that node.  See memmap_init_zone()
1287 # for details.
1288 config NODES_SPAN_OTHER_NODES
1289         def_bool y
1290         depends on X86_64_ACPI_NUMA
1291 
1292 config NUMA_EMU
1293         bool "NUMA emulation"
1294         depends on NUMA
1295         ---help---
1296           Enable NUMA emulation. A flat machine will be split
1297           into virtual nodes when booted with "numa=fake=N", where N is the
1298           number of nodes. This is only useful for debugging.
1299 
1300 config NODES_SHIFT
1301         int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1302         range 1 10
1303         default "10" if MAXSMP
1304         default "6" if X86_64
1305         default "4" if X86_NUMAQ
1306         default "3"
1307         depends on NEED_MULTIPLE_NODES
1308         ---help---
1309           Specify the maximum number of NUMA Nodes available on the target
1310           system.  Increases memory reserved to accommodate various tables.
1311 
1312 config ARCH_HAVE_MEMORY_PRESENT
1313         def_bool y
1314         depends on X86_32 && DISCONTIGMEM
1315 
1316 config NEED_NODE_MEMMAP_SIZE
1317         def_bool y
1318         depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1319 
1320 config ARCH_FLATMEM_ENABLE
1321         def_bool y
1322         depends on X86_32 && !NUMA
1323 
1324 config ARCH_DISCONTIGMEM_ENABLE
1325         def_bool y
1326         depends on NUMA && X86_32
1327 
1328 config ARCH_DISCONTIGMEM_DEFAULT
1329         def_bool y
1330         depends on NUMA && X86_32
1331 
1332 config ARCH_SPARSEMEM_ENABLE
1333         def_bool y
1334         depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1335         select SPARSEMEM_STATIC if X86_32
1336         select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1337 
1338 config ARCH_SPARSEMEM_DEFAULT
1339         def_bool y
1340         depends on X86_64
1341 
1342 config ARCH_SELECT_MEMORY_MODEL
1343         def_bool y
1344         depends on ARCH_SPARSEMEM_ENABLE
1345 
1346 config ARCH_MEMORY_PROBE
1347         bool "Enable sysfs memory/probe interface"
1348         depends on X86_64 && MEMORY_HOTPLUG
1349         help
1350           This option enables a sysfs memory/probe interface for testing.
1351           See Documentation/memory-hotplug.txt for more information.
1352           If you are unsure how to answer this question, answer N.
1353 
1354 config ARCH_PROC_KCORE_TEXT
1355         def_bool y
1356         depends on X86_64 && PROC_KCORE
1357 
1358 config ILLEGAL_POINTER_VALUE
1359        hex
1360        default 0 if X86_32
1361        default 0xdead000000000000 if X86_64
1362 
1363 source "mm/Kconfig"
1364 
1365 config HIGHPTE
1366         bool "Allocate 3rd-level pagetables from highmem"
1367         depends on HIGHMEM
1368         ---help---
1369           The VM uses one page table entry for each page of physical memory.
1370           For systems with a lot of RAM, this can be wasteful of precious
1371           low memory.  Setting this option will put user-space page table
1372           entries in high memory.
1373 
1374 config X86_CHECK_BIOS_CORRUPTION
1375         bool "Check for low memory corruption"
1376         ---help---
1377           Periodically check for memory corruption in low memory, which
1378           is suspected to be caused by BIOS.  Even when enabled in the
1379           configuration, it is disabled at runtime.  Enable it by
1380           setting "memory_corruption_check=1" on the kernel command
1381           line.  By default it scans the low 64k of memory every 60
1382           seconds; see the memory_corruption_check_size and
1383           memory_corruption_check_period parameters in
1384           Documentation/kernel-parameters.txt to adjust this.
1385 
1386           When enabled with the default parameters, this option has
1387           almost no overhead, as it reserves a relatively small amount
1388           of memory and scans it infrequently.  It both detects corruption
1389           and prevents it from affecting the running system.
1390 
1391           It is, however, intended as a diagnostic tool; if repeatable
1392           BIOS-originated corruption always affects the same memory,
1393           you can use memmap= to prevent the kernel from using that
1394           memory.
1395 
1396 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1397         bool "Set the default setting of memory_corruption_check"
1398         depends on X86_CHECK_BIOS_CORRUPTION
1399         default y
1400         ---help---
1401           Set whether the default state of memory_corruption_check is
1402           on or off.
1403 
1404 config X86_RESERVE_LOW
1405         int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1406         default 64
1407         range 4 640
1408         ---help---
1409           Specify the amount of low memory to reserve for the BIOS.
1410 
1411           The first page contains BIOS data structures that the kernel
1412           must not use, so that page must always be reserved.
1413 
1414           By default we reserve the first 64K of physical RAM, as a
1415           number of BIOSes are known to corrupt that memory range
1416           during events such as suspend/resume or monitor cable
1417           insertion, so it must not be used by the kernel.
1418 
1419           You can set this to 4 if you are absolutely sure that you
1420           trust the BIOS to get all its memory reservations and usages
1421           right.  If you know your BIOS have problems beyond the
1422           default 64K area, you can set this to 640 to avoid using the
1423           entire low memory range.
1424 
1425           If you have doubts about the BIOS (e.g. suspend/resume does
1426           not work or there's kernel crashes after certain hardware
1427           hotplug events) then you might want to enable
1428           X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1429           typical corruption patterns.
1430 
1431           Leave this to the default value of 64 if you are unsure.
1432 
1433 config MATH_EMULATION
1434         bool
1435         prompt "Math emulation" if X86_32
1436         ---help---
1437           Linux can emulate a math coprocessor (used for floating point
1438           operations) if you don't have one. 486DX and Pentium processors have
1439           a math coprocessor built in, 486SX and 386 do not, unless you added
1440           a 487DX or 387, respectively. (The messages during boot time can
1441           give you some hints here ["man dmesg"].) Everyone needs either a
1442           coprocessor or this emulation.
1443 
1444           If you don't have a math coprocessor, you need to say Y here; if you
1445           say Y here even though you have a coprocessor, the coprocessor will
1446           be used nevertheless. (This behavior can be changed with the kernel
1447           command line option "no387", which comes handy if your coprocessor
1448           is broken. Try "man bootparam" or see the documentation of your boot
1449           loader (lilo or loadlin) about how to pass options to the kernel at
1450           boot time.) This means that it is a good idea to say Y here if you
1451           intend to use this kernel on different machines.
1452 
1453           More information about the internals of the Linux math coprocessor
1454           emulation can be found in <file:arch/x86/math-emu/README>.
1455 
1456           If you are not sure, say Y; apart from resulting in a 66 KB bigger
1457           kernel, it won't hurt.
1458 
1459 config MTRR
1460         def_bool y
1461         prompt "MTRR (Memory Type Range Register) support" if EXPERT
1462         ---help---
1463           On Intel P6 family processors (Pentium Pro, Pentium II and later)
1464           the Memory Type Range Registers (MTRRs) may be used to control
1465           processor access to memory ranges. This is most useful if you have
1466           a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1467           allows bus write transfers to be combined into a larger transfer
1468           before bursting over the PCI/AGP bus. This can increase performance
1469           of image write operations 2.5 times or more. Saying Y here creates a
1470           /proc/mtrr file which may be used to manipulate your processor's
1471           MTRRs. Typically the X server should use this.
1472 
1473           This code has a reasonably generic interface so that similar
1474           control registers on other processors can be easily supported
1475           as well:
1476 
1477           The Cyrix 6x86, 6x86MX and M II processors have Address Range
1478           Registers (ARRs) which provide a similar functionality to MTRRs. For
1479           these, the ARRs are used to emulate the MTRRs.
1480           The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1481           MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1482           write-combining. All of these processors are supported by this code
1483           and it makes sense to say Y here if you have one of them.
1484 
1485           Saying Y here also fixes a problem with buggy SMP BIOSes which only
1486           set the MTRRs for the boot CPU and not for the secondary CPUs. This
1487           can lead to all sorts of problems, so it's good to say Y here.
1488 
1489           You can safely say Y even if your machine doesn't have MTRRs, you'll
1490           just add about 9 KB to your kernel.
1491 
1492           See <file:Documentation/x86/mtrr.txt> for more information.
1493 
1494 config MTRR_SANITIZER
1495         def_bool y
1496         prompt "MTRR cleanup support"
1497         depends on MTRR
1498         ---help---
1499           Convert MTRR layout from continuous to discrete, so X drivers can
1500           add writeback entries.
1501 
1502           Can be disabled with disable_mtrr_cleanup on the kernel command line.
1503           The largest mtrr entry size for a continuous block can be set with
1504           mtrr_chunk_size.
1505 
1506           If unsure, say Y.
1507 
1508 config MTRR_SANITIZER_ENABLE_DEFAULT
1509         int "MTRR cleanup enable value (0-1)"
1510         range 0 1
1511         default "0"
1512         depends on MTRR_SANITIZER
1513         ---help---
1514           Enable mtrr cleanup default value
1515 
1516 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1517         int "MTRR cleanup spare reg num (0-7)"
1518         range 0 7
1519         default "1"
1520         depends on MTRR_SANITIZER
1521         ---help---
1522           mtrr cleanup spare entries default, it can be changed via
1523           mtrr_spare_reg_nr=N on the kernel command line.
1524 
1525 config X86_PAT
1526         def_bool y
1527         prompt "x86 PAT support" if EXPERT
1528         depends on MTRR
1529         ---help---
1530           Use PAT attributes to setup page level cache control.
1531 
1532           PATs are the modern equivalents of MTRRs and are much more
1533           flexible than MTRRs.
1534 
1535           Say N here if you see bootup problems (boot crash, boot hang,
1536           spontaneous reboots) or a non-working video driver.
1537 
1538           If unsure, say Y.
1539 
1540 config ARCH_USES_PG_UNCACHED
1541         def_bool y
1542         depends on X86_PAT
1543 
1544 config ARCH_RANDOM
1545         def_bool y
1546         prompt "x86 architectural random number generator" if EXPERT
1547         ---help---
1548           Enable the x86 architectural RDRAND instruction
1549           (Intel Bull Mountain technology) to generate random numbers.
1550           If supported, this is a high bandwidth, cryptographically
1551           secure hardware random number generator.
1552 
1553 config X86_SMAP
1554         def_bool y
1555         prompt "Supervisor Mode Access Prevention" if EXPERT
1556         ---help---
1557           Supervisor Mode Access Prevention (SMAP) is a security
1558           feature in newer Intel processors.  There is a small
1559           performance cost if this enabled and turned on; there is
1560           also a small increase in the kernel size if this is enabled.
1561 
1562           If unsure, say Y.
1563 
1564 config EFI
1565         bool "EFI runtime service support"
1566         depends on ACPI
1567         select UCS2_STRING
1568         ---help---
1569           This enables the kernel to use EFI runtime services that are
1570           available (such as the EFI variable services).
1571 
1572           This option is only useful on systems that have EFI firmware.
1573           In addition, you should use the latest ELILO loader available
1574           at <http://elilo.sourceforge.net> in order to take advantage
1575           of EFI runtime services. However, even with this option, the
1576           resultant kernel should continue to boot on existing non-EFI
1577           platforms.
1578 
1579 config EFI_STUB
1580        bool "EFI stub support"
1581        depends on EFI
1582        ---help---
1583           This kernel feature allows a bzImage to be loaded directly
1584           by EFI firmware without the use of a bootloader.
1585 
1586           See Documentation/efi-stub.txt for more information.
1587 
1588 config SECCOMP
1589         def_bool y
1590         prompt "Enable seccomp to safely compute untrusted bytecode"
1591         ---help---
1592           This kernel feature is useful for number crunching applications
1593           that may need to compute untrusted bytecode during their
1594           execution. By using pipes or other transports made available to
1595           the process as file descriptors supporting the read/write
1596           syscalls, it's possible to isolate those applications in
1597           their own address space using seccomp. Once seccomp is
1598           enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1599           and the task is only allowed to execute a few safe syscalls
1600           defined by each seccomp mode.
1601 
1602           If unsure, say Y. Only embedded should say N here.
1603 
1604 source kernel/Kconfig.hz
1605 
1606 config KEXEC
1607         bool "kexec system call"
1608         ---help---
1609           kexec is a system call that implements the ability to shutdown your
1610           current kernel, and to start another kernel.  It is like a reboot
1611           but it is independent of the system firmware.   And like a reboot
1612           you can start any kernel with it, not just Linux.
1613 
1614           The name comes from the similarity to the exec system call.
1615 
1616           It is an ongoing process to be certain the hardware in a machine
1617           is properly shutdown, so do not be surprised if this code does not
1618           initially work for you.  As of this writing the exact hardware
1619           interface is strongly in flux, so no good recommendation can be
1620           made.
1621 
1622 config CRASH_DUMP
1623         bool "kernel crash dumps"
1624         depends on X86_64 || (X86_32 && HIGHMEM)
1625         ---help---
1626           Generate crash dump after being started by kexec.
1627           This should be normally only set in special crash dump kernels
1628           which are loaded in the main kernel with kexec-tools into
1629           a specially reserved region and then later executed after
1630           a crash by kdump/kexec. The crash dump kernel must be compiled
1631           to a memory address not used by the main kernel or BIOS using
1632           PHYSICAL_START, or it must be built as a relocatable image
1633           (CONFIG_RELOCATABLE=y).
1634           For more details see Documentation/kdump/kdump.txt
1635 
1636 config KEXEC_JUMP
1637         bool "kexec jump"
1638         depends on KEXEC && HIBERNATION
1639         ---help---
1640           Jump between original kernel and kexeced kernel and invoke
1641           code in physical address mode via KEXEC
1642 
1643 config PHYSICAL_START
1644         hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1645         default "0x1000000"
1646         ---help---
1647           This gives the physical address where the kernel is loaded.
1648 
1649           If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1650           bzImage will decompress itself to above physical address and
1651           run from there. Otherwise, bzImage will run from the address where
1652           it has been loaded by the boot loader and will ignore above physical
1653           address.
1654 
1655           In normal kdump cases one does not have to set/change this option
1656           as now bzImage can be compiled as a completely relocatable image
1657           (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1658           address. This option is mainly useful for the folks who don't want
1659           to use a bzImage for capturing the crash dump and want to use a
1660           vmlinux instead. vmlinux is not relocatable hence a kernel needs
1661           to be specifically compiled to run from a specific memory area
1662           (normally a reserved region) and this option comes handy.
1663 
1664           So if you are using bzImage for capturing the crash dump,
1665           leave the value here unchanged to 0x1000000 and set
1666           CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
1667           for capturing the crash dump change this value to start of
1668           the reserved region.  In other words, it can be set based on
1669           the "X" value as specified in the "crashkernel=YM@XM"
1670           command line boot parameter passed to the panic-ed
1671           kernel. Please take a look at Documentation/kdump/kdump.txt
1672           for more details about crash dumps.
1673 
1674           Usage of bzImage for capturing the crash dump is recommended as
1675           one does not have to build two kernels. Same kernel can be used
1676           as production kernel and capture kernel. Above option should have
1677           gone away after relocatable bzImage support is introduced. But it
1678           is present because there are users out there who continue to use
1679           vmlinux for dump capture. This option should go away down the
1680           line.
1681 
1682           Don't change this unless you know what you are doing.
1683 
1684 config RELOCATABLE
1685         bool "Build a relocatable kernel"
1686         default y
1687         ---help---
1688           This builds a kernel image that retains relocation information
1689           so it can be loaded someplace besides the default 1MB.
1690           The relocations tend to make the kernel binary about 10% larger,
1691           but are discarded at runtime.
1692 
1693           One use is for the kexec on panic case where the recovery kernel
1694           must live at a different physical address than the primary
1695           kernel.
1696 
1697           Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1698           it has been loaded at and the compile time physical address
1699           (CONFIG_PHYSICAL_START) is used as the minimum location.
1700 
1701 config RANDOMIZE_BASE
1702         bool "Randomize the address of the kernel image"
1703         depends on RELOCATABLE
1704         depends on !HIBERNATION
1705         default n
1706         ---help---
1707            Randomizes the physical and virtual address at which the
1708            kernel image is decompressed, as a security feature that
1709            deters exploit attempts relying on knowledge of the location
1710            of kernel internals.
1711 
1712            Entropy is generated using the RDRAND instruction if it is
1713            supported. If RDTSC is supported, it is used as well. If
1714            neither RDRAND nor RDTSC are supported, then randomness is
1715            read from the i8254 timer.
1716 
1717            The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1718            and aligned according to PHYSICAL_ALIGN. Since the kernel is
1719            built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1720            minimum of 2MiB, only 10 bits of entropy is theoretically
1721            possible. At best, due to page table layouts, 64-bit can use
1722            9 bits of entropy and 32-bit uses 8 bits.
1723 
1724            If unsure, say N.
1725 
1726 config RANDOMIZE_BASE_MAX_OFFSET
1727         hex "Maximum kASLR offset allowed" if EXPERT
1728         depends on RANDOMIZE_BASE
1729         range 0x0 0x20000000 if X86_32
1730         default "0x20000000" if X86_32
1731         range 0x0 0x40000000 if X86_64
1732         default "0x40000000" if X86_64
1733         ---help---
1734           The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1735           memory is used to determine the maximal offset in bytes that will
1736           be applied to the kernel when kernel Address Space Layout
1737           Randomization (kASLR) is active. This must be a multiple of
1738           PHYSICAL_ALIGN.
1739 
1740           On 32-bit this is limited to 512MiB by page table layouts. The
1741           default is 512MiB.
1742 
1743           On 64-bit this is limited by how the kernel fixmap page table is
1744           positioned, so this cannot be larger than 1GiB currently. Without
1745           RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1746           and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1747           modules area will shrink to compensate, up to the current maximum
1748           1GiB to 1GiB split. The default is 1GiB.
1749 
1750           If unsure, leave at the default value.
1751 
1752 # Relocation on x86 needs some additional build support
1753 config X86_NEED_RELOCS
1754         def_bool y
1755         depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1756 
1757 config PHYSICAL_ALIGN
1758         hex "Alignment value to which kernel should be aligned"
1759         default "0x200000"
1760         range 0x2000 0x1000000 if X86_32
1761         range 0x200000 0x1000000 if X86_64
1762         ---help---
1763           This value puts the alignment restrictions on physical address
1764           where kernel is loaded and run from. Kernel is compiled for an
1765           address which meets above alignment restriction.
1766 
1767           If bootloader loads the kernel at a non-aligned address and
1768           CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1769           address aligned to above value and run from there.
1770 
1771           If bootloader loads the kernel at a non-aligned address and
1772           CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1773           load address and decompress itself to the address it has been
1774           compiled for and run from there. The address for which kernel is
1775           compiled already meets above alignment restrictions. Hence the
1776           end result is that kernel runs from a physical address meeting
1777           above alignment restrictions.
1778 
1779           On 32-bit this value must be a multiple of 0x2000. On 64-bit
1780           this value must be a multiple of 0x200000.
1781 
1782           Don't change this unless you know what you are doing.
1783 
1784 config HOTPLUG_CPU
1785         bool "Support for hot-pluggable CPUs"
1786         depends on SMP
1787         ---help---
1788           Say Y here to allow turning CPUs off and on. CPUs can be
1789           controlled through /sys/devices/system/cpu.
1790           ( Note: power management support will enable this option
1791             automatically on SMP systems. )
1792           Say N if you want to disable CPU hotplug.
1793 
1794 config BOOTPARAM_HOTPLUG_CPU0
1795         bool "Set default setting of cpu0_hotpluggable"
1796         default n
1797         depends on HOTPLUG_CPU
1798         ---help---
1799           Set whether default state of cpu0_hotpluggable is on or off.
1800 
1801           Say Y here to enable CPU0 hotplug by default. If this switch
1802           is turned on, there is no need to give cpu0_hotplug kernel
1803           parameter and the CPU0 hotplug feature is enabled by default.
1804 
1805           Please note: there are two known CPU0 dependencies if you want
1806           to enable the CPU0 hotplug feature either by this switch or by
1807           cpu0_hotplug kernel parameter.
1808 
1809           First, resume from hibernate or suspend always starts from CPU0.
1810           So hibernate and suspend are prevented if CPU0 is offline.
1811 
1812           Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1813           offline if any interrupt can not migrate out of CPU0. There may
1814           be other CPU0 dependencies.
1815 
1816           Please make sure the dependencies are under your control before
1817           you enable this feature.
1818 
1819           Say N if you don't want to enable CPU0 hotplug feature by default.
1820           You still can enable the CPU0 hotplug feature at boot by kernel
1821           parameter cpu0_hotplug.
1822 
1823 config DEBUG_HOTPLUG_CPU0
1824         def_bool n
1825         prompt "Debug CPU0 hotplug"
1826         depends on HOTPLUG_CPU
1827         ---help---
1828           Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1829           soon as possible and boots up userspace with CPU0 offlined. User
1830           can online CPU0 back after boot time.
1831 
1832           To debug CPU0 hotplug, you need to enable CPU0 offline/online
1833           feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1834           compilation or giving cpu0_hotplug kernel parameter at boot.
1835 
1836           If unsure, say N.
1837 
1838 config COMPAT_VDSO
1839         def_bool y
1840         prompt "Compat VDSO support"
1841         depends on X86_32 || IA32_EMULATION
1842         ---help---
1843           Map the 32-bit VDSO to the predictable old-style address too.
1844 
1845           Say N here if you are running a sufficiently recent glibc
1846           version (2.3.3 or later), to remove the high-mapped
1847           VDSO mapping and to exclusively use the randomized VDSO.
1848 
1849           If unsure, say Y.
1850 
1851 config CMDLINE_BOOL
1852         bool "Built-in kernel command line"
1853         ---help---
1854           Allow for specifying boot arguments to the kernel at
1855           build time.  On some systems (e.g. embedded ones), it is
1856           necessary or convenient to provide some or all of the
1857           kernel boot arguments with the kernel itself (that is,
1858           to not rely on the boot loader to provide them.)
1859 
1860           To compile command line arguments into the kernel,
1861           set this option to 'Y', then fill in the
1862           the boot arguments in CONFIG_CMDLINE.
1863 
1864           Systems with fully functional boot loaders (i.e. non-embedded)
1865           should leave this option set to 'N'.
1866 
1867 config CMDLINE
1868         string "Built-in kernel command string"
1869         depends on CMDLINE_BOOL
1870         default ""
1871         ---help---
1872           Enter arguments here that should be compiled into the kernel
1873           image and used at boot time.  If the boot loader provides a
1874           command line at boot time, it is appended to this string to
1875           form the full kernel command line, when the system boots.
1876 
1877           However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1878           change this behavior.
1879 
1880           In most cases, the command line (whether built-in or provided
1881           by the boot loader) should specify the device for the root
1882           file system.
1883 
1884 config CMDLINE_OVERRIDE
1885         bool "Built-in command line overrides boot loader arguments"
1886         depends on CMDLINE_BOOL
1887         ---help---
1888           Set this option to 'Y' to have the kernel ignore the boot loader
1889           command line, and use ONLY the built-in command line.
1890 
1891           This is used to work around broken boot loaders.  This should
1892           be set to 'N' under normal conditions.
1893 
1894 endmenu
1895 
1896 config ARCH_ENABLE_MEMORY_HOTPLUG
1897         def_bool y
1898         depends on X86_64 || (X86_32 && HIGHMEM)
1899 
1900 config ARCH_ENABLE_MEMORY_HOTREMOVE
1901         def_bool y
1902         depends on MEMORY_HOTPLUG
1903 
1904 config USE_PERCPU_NUMA_NODE_ID
1905         def_bool y
1906         depends on NUMA
1907 
1908 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1909         def_bool y
1910         depends on X86_64 || X86_PAE
1911 
1912 menu "Power management and ACPI options"
1913 
1914 config ARCH_HIBERNATION_HEADER
1915         def_bool y
1916         depends on X86_64 && HIBERNATION
1917 
1918 source "kernel/power/Kconfig"
1919 
1920 source "drivers/acpi/Kconfig"
1921 
1922 source "drivers/sfi/Kconfig"
1923 
1924 config X86_APM_BOOT
1925         def_bool y
1926         depends on APM
1927 
1928 menuconfig APM
1929         tristate "APM (Advanced Power Management) BIOS support"
1930         depends on X86_32 && PM_SLEEP
1931         ---help---
1932           APM is a BIOS specification for saving power using several different
1933           techniques. This is mostly useful for battery powered laptops with
1934           APM compliant BIOSes. If you say Y here, the system time will be
1935           reset after a RESUME operation, the /proc/apm device will provide
1936           battery status information, and user-space programs will receive
1937           notification of APM "events" (e.g. battery status change).
1938 
1939           If you select "Y" here, you can disable actual use of the APM
1940           BIOS by passing the "apm=off" option to the kernel at boot time.
1941 
1942           Note that the APM support is almost completely disabled for
1943           machines with more than one CPU.
1944 
1945           In order to use APM, you will need supporting software. For location
1946           and more information, read <file:Documentation/power/apm-acpi.txt>
1947           and the Battery Powered Linux mini-HOWTO, available from
1948           <http://www.tldp.org/docs.html#howto>.
1949 
1950           This driver does not spin down disk drives (see the hdparm(8)
1951           manpage ("man 8 hdparm") for that), and it doesn't turn off
1952           VESA-compliant "green" monitors.
1953 
1954           This driver does not support the TI 4000M TravelMate and the ACER
1955           486/DX4/75 because they don't have compliant BIOSes. Many "green"
1956           desktop machines also don't have compliant BIOSes, and this driver
1957           may cause those machines to panic during the boot phase.
1958 
1959           Generally, if you don't have a battery in your machine, there isn't
1960           much point in using this driver and you should say N. If you get
1961           random kernel OOPSes or reboots that don't seem to be related to
1962           anything, try disabling/enabling this option (or disabling/enabling
1963           APM in your BIOS).
1964 
1965           Some other things you should try when experiencing seemingly random,
1966           "weird" problems:
1967 
1968           1) make sure that you have enough swap space and that it is
1969           enabled.
1970           2) pass the "no-hlt" option to the kernel
1971           3) switch on floating point emulation in the kernel and pass
1972           the "no387" option to the kernel
1973           4) pass the "floppy=nodma" option to the kernel
1974           5) pass the "mem=4M" option to the kernel (thereby disabling
1975           all but the first 4 MB of RAM)
1976           6) make sure that the CPU is not over clocked.
1977           7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1978           8) disable the cache from your BIOS settings
1979           9) install a fan for the video card or exchange video RAM
1980           10) install a better fan for the CPU
1981           11) exchange RAM chips
1982           12) exchange the motherboard.
1983 
1984           To compile this driver as a module, choose M here: the
1985           module will be called apm.
1986 
1987 if APM
1988 
1989 config APM_IGNORE_USER_SUSPEND
1990         bool "Ignore USER SUSPEND"
1991         ---help---
1992           This option will ignore USER SUSPEND requests. On machines with a
1993           compliant APM BIOS, you want to say N. However, on the NEC Versa M
1994           series notebooks, it is necessary to say Y because of a BIOS bug.
1995 
1996 config APM_DO_ENABLE
1997         bool "Enable PM at boot time"
1998         ---help---
1999           Enable APM features at boot time. From page 36 of the APM BIOS
2000           specification: "When disabled, the APM BIOS does not automatically
2001           power manage devices, enter the Standby State, enter the Suspend
2002           State, or take power saving steps in response to CPU Idle calls."
2003           This driver will make CPU Idle calls when Linux is idle (unless this
2004           feature is turned off -- see "Do CPU IDLE calls", below). This
2005           should always save battery power, but more complicated APM features
2006           will be dependent on your BIOS implementation. You may need to turn
2007           this option off if your computer hangs at boot time when using APM
2008           support, or if it beeps continuously instead of suspending. Turn
2009           this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2010           T400CDT. This is off by default since most machines do fine without
2011           this feature.
2012 
2013 config APM_CPU_IDLE
2014         depends on CPU_IDLE
2015         bool "Make CPU Idle calls when idle"
2016         ---help---
2017           Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2018           On some machines, this can activate improved power savings, such as
2019           a slowed CPU clock rate, when the machine is idle. These idle calls
2020           are made after the idle loop has run for some length of time (e.g.,
2021           333 mS). On some machines, this will cause a hang at boot time or
2022           whenever the CPU becomes idle. (On machines with more than one CPU,
2023           this option does nothing.)
2024 
2025 config APM_DISPLAY_BLANK
2026         bool "Enable console blanking using APM"
2027         ---help---
2028           Enable console blanking using the APM. Some laptops can use this to
2029           turn off the LCD backlight when the screen blanker of the Linux
2030           virtual console blanks the screen. Note that this is only used by
2031           the virtual console screen blanker, and won't turn off the backlight
2032           when using the X Window system. This also doesn't have anything to
2033           do with your VESA-compliant power-saving monitor. Further, this
2034           option doesn't work for all laptops -- it might not turn off your
2035           backlight at all, or it might print a lot of errors to the console,
2036           especially if you are using gpm.
2037 
2038 config APM_ALLOW_INTS
2039         bool "Allow interrupts during APM BIOS calls"
2040         ---help---
2041           Normally we disable external interrupts while we are making calls to
2042           the APM BIOS as a measure to lessen the effects of a badly behaving
2043           BIOS implementation.  The BIOS should reenable interrupts if it
2044           needs to.  Unfortunately, some BIOSes do not -- especially those in
2045           many of the newer IBM Thinkpads.  If you experience hangs when you
2046           suspend, try setting this to Y.  Otherwise, say N.
2047 
2048 endif # APM
2049 
2050 source "drivers/cpufreq/Kconfig"
2051 
2052 source "drivers/cpuidle/Kconfig"
2053 
2054 source "drivers/idle/Kconfig"
2055 
2056 endmenu
2057 
2058 
2059 menu "Bus options (PCI etc.)"
2060 
2061 config PCI
2062         bool "PCI support"
2063         default y
2064         ---help---
2065           Find out whether you have a PCI motherboard. PCI is the name of a
2066           bus system, i.e. the way the CPU talks to the other stuff inside
2067           your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2068           VESA. If you have PCI, say Y, otherwise N.
2069 
2070 choice
2071         prompt "PCI access mode"
2072         depends on X86_32 && PCI
2073         default PCI_GOANY
2074         ---help---
2075           On PCI systems, the BIOS can be used to detect the PCI devices and
2076           determine their configuration. However, some old PCI motherboards
2077           have BIOS bugs and may crash if this is done. Also, some embedded
2078           PCI-based systems don't have any BIOS at all. Linux can also try to
2079           detect the PCI hardware directly without using the BIOS.
2080 
2081           With this option, you can specify how Linux should detect the
2082           PCI devices. If you choose "BIOS", the BIOS will be used,
2083           if you choose "Direct", the BIOS won't be used, and if you
2084           choose "MMConfig", then PCI Express MMCONFIG will be used.
2085           If you choose "Any", the kernel will try MMCONFIG, then the
2086           direct access method and falls back to the BIOS if that doesn't
2087           work. If unsure, go with the default, which is "Any".
2088 
2089 config PCI_GOBIOS
2090         bool "BIOS"
2091 
2092 config PCI_GOMMCONFIG
2093         bool "MMConfig"
2094 
2095 config PCI_GODIRECT
2096         bool "Direct"
2097 
2098 config PCI_GOOLPC
2099         bool "OLPC XO-1"
2100         depends on OLPC
2101 
2102 config PCI_GOANY
2103         bool "Any"
2104 
2105 endchoice
2106 
2107 config PCI_BIOS
2108         def_bool y
2109         depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2110 
2111 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2112 config PCI_DIRECT
2113         def_bool y
2114         depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2115 
2116 config PCI_MMCONFIG
2117         def_bool y
2118         depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2119 
2120 config PCI_OLPC
2121         def_bool y
2122         depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2123 
2124 config PCI_XEN
2125         def_bool y
2126         depends on PCI && XEN
2127         select SWIOTLB_XEN
2128 
2129 config PCI_DOMAINS
2130         def_bool y
2131         depends on PCI
2132 
2133 config PCI_MMCONFIG
2134         bool "Support mmconfig PCI config space access"
2135         depends on X86_64 && PCI && ACPI
2136 
2137 config PCI_CNB20LE_QUIRK
2138         bool "Read CNB20LE Host Bridge Windows" if EXPERT
2139         depends on PCI
2140         help
2141           Read the PCI windows out of the CNB20LE host bridge. This allows
2142           PCI hotplug to work on systems with the CNB20LE chipset which do
2143           not have ACPI.
2144 
2145           There's no public spec for this chipset, and this functionality
2146           is known to be incomplete.
2147 
2148           You should say N unless you know you need this.
2149 
2150 source "drivers/pci/pcie/Kconfig"
2151 
2152 source "drivers/pci/Kconfig"
2153 
2154 # x86_64 have no ISA slots, but can have ISA-style DMA.
2155 config ISA_DMA_API
2156         bool "ISA-style DMA support" if (X86_64 && EXPERT)
2157         default y
2158         help
2159           Enables ISA-style DMA support for devices requiring such controllers.
2160           If unsure, say Y.
2161 
2162 if X86_32
2163 
2164 config ISA
2165         bool "ISA support"
2166         ---help---
2167           Find out whether you have ISA slots on your motherboard.  ISA is the
2168           name of a bus system, i.e. the way the CPU talks to the other stuff
2169           inside your box.  Other bus systems are PCI, EISA, MicroChannel
2170           (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2171           newer boards don't support it.  If you have ISA, say Y, otherwise N.
2172 
2173 config EISA
2174         bool "EISA support"
2175         depends on ISA
2176         ---help---
2177           The Extended Industry Standard Architecture (EISA) bus was
2178           developed as an open alternative to the IBM MicroChannel bus.
2179 
2180           The EISA bus provided some of the features of the IBM MicroChannel
2181           bus while maintaining backward compatibility with cards made for
2182           the older ISA bus.  The EISA bus saw limited use between 1988 and
2183           1995 when it was made obsolete by the PCI bus.
2184 
2185           Say Y here if you are building a kernel for an EISA-based machine.
2186 
2187           Otherwise, say N.
2188 
2189 source "drivers/eisa/Kconfig"
2190 
2191 config SCx200
2192         tristate "NatSemi SCx200 support"
2193         ---help---
2194           This provides basic support for National Semiconductor's
2195           (now AMD's) Geode processors.  The driver probes for the
2196           PCI-IDs of several on-chip devices, so its a good dependency
2197           for other scx200_* drivers.
2198 
2199           If compiled as a module, the driver is named scx200.
2200 
2201 config SCx200HR_TIMER
2202         tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2203         depends on SCx200
2204         default y
2205         ---help---
2206           This driver provides a clocksource built upon the on-chip
2207           27MHz high-resolution timer.  Its also a workaround for
2208           NSC Geode SC-1100's buggy TSC, which loses time when the
2209           processor goes idle (as is done by the scheduler).  The
2210           other workaround is idle=poll boot option.
2211 
2212 config OLPC
2213         bool "One Laptop Per Child support"
2214         depends on !X86_PAE
2215         select GPIOLIB
2216         select OF
2217         select OF_PROMTREE
2218         select IRQ_DOMAIN
2219         ---help---
2220           Add support for detecting the unique features of the OLPC
2221           XO hardware.
2222 
2223 config OLPC_XO1_PM
2224         bool "OLPC XO-1 Power Management"
2225         depends on OLPC && MFD_CS5535 && PM_SLEEP
2226         select MFD_CORE
2227         ---help---
2228           Add support for poweroff and suspend of the OLPC XO-1 laptop.
2229 
2230 config OLPC_XO1_RTC
2231         bool "OLPC XO-1 Real Time Clock"
2232         depends on OLPC_XO1_PM && RTC_DRV_CMOS
2233         ---help---
2234           Add support for the XO-1 real time clock, which can be used as a
2235           programmable wakeup source.
2236 
2237 config OLPC_XO1_SCI
2238         bool "OLPC XO-1 SCI extras"
2239         depends on OLPC && OLPC_XO1_PM
2240         depends on INPUT=y
2241         select POWER_SUPPLY
2242         select GPIO_CS5535
2243         select MFD_CORE
2244         ---help---
2245           Add support for SCI-based features of the OLPC XO-1 laptop:
2246            - EC-driven system wakeups
2247            - Power button
2248            - Ebook switch
2249            - Lid switch
2250            - AC adapter status updates
2251            - Battery status updates
2252 
2253 config OLPC_XO15_SCI
2254         bool "OLPC XO-1.5 SCI extras"
2255         depends on OLPC && ACPI
2256         select POWER_SUPPLY
2257         ---help---
2258           Add support for SCI-based features of the OLPC XO-1.5 laptop:
2259            - EC-driven system wakeups
2260            - AC adapter status updates
2261            - Battery status updates
2262 
2263 config ALIX
2264         bool "PCEngines ALIX System Support (LED setup)"
2265         select GPIOLIB
2266         ---help---
2267           This option enables system support for the PCEngines ALIX.
2268           At present this just sets up LEDs for GPIO control on
2269           ALIX2/3/6 boards.  However, other system specific setup should
2270           get added here.
2271 
2272           Note: You must still enable the drivers for GPIO and LED support
2273           (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2274 
2275           Note: You have to set alix.force=1 for boards with Award BIOS.
2276 
2277 config NET5501
2278         bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2279         select GPIOLIB
2280         ---help---
2281           This option enables system support for the Soekris Engineering net5501.
2282 
2283 config GEOS
2284         bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2285         select GPIOLIB
2286         depends on DMI
2287         ---help---
2288           This option enables system support for the Traverse Technologies GEOS.
2289 
2290 config TS5500
2291         bool "Technologic Systems TS-5500 platform support"
2292         depends on MELAN
2293         select CHECK_SIGNATURE
2294         select NEW_LEDS
2295         select LEDS_CLASS
2296         ---help---
2297           This option enables system support for the Technologic Systems TS-5500.
2298 
2299 endif # X86_32
2300 
2301 config AMD_NB
2302         def_bool y
2303         depends on CPU_SUP_AMD && PCI
2304 
2305 source "drivers/pcmcia/Kconfig"
2306 
2307 source "drivers/pci/hotplug/Kconfig"
2308 
2309 config RAPIDIO
2310         tristate "RapidIO support"
2311         depends on PCI
2312         default n
2313         help
2314           If enabled this option will include drivers and the core
2315           infrastructure code to support RapidIO interconnect devices.
2316 
2317 source "drivers/rapidio/Kconfig"
2318 
2319 config X86_SYSFB
2320         bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2321         help
2322           Firmwares often provide initial graphics framebuffers so the BIOS,
2323           bootloader or kernel can show basic video-output during boot for
2324           user-guidance and debugging. Historically, x86 used the VESA BIOS
2325           Extensions and EFI-framebuffers for this, which are mostly limited
2326           to x86.
2327           This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2328           framebuffers so the new generic system-framebuffer drivers can be
2329           used on x86. If the framebuffer is not compatible with the generic
2330           modes, it is adverticed as fallback platform framebuffer so legacy
2331           drivers like efifb, vesafb and uvesafb can pick it up.
2332           If this option is not selected, all system framebuffers are always
2333           marked as fallback platform framebuffers as usual.
2334 
2335           Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2336           not be able to pick up generic system framebuffers if this option
2337           is selected. You are highly encouraged to enable simplefb as
2338           replacement if you select this option. simplefb can correctly deal
2339           with generic system framebuffers. But you should still keep vesafb
2340           and others enabled as fallback if a system framebuffer is
2341           incompatible with simplefb.
2342 
2343           If unsure, say Y.
2344 
2345 endmenu
2346 
2347 
2348 menu "Executable file formats / Emulations"
2349 
2350 source "fs/Kconfig.binfmt"
2351 
2352 config IA32_EMULATION
2353         bool "IA32 Emulation"
2354         depends on X86_64
2355         select BINFMT_ELF
2356         select COMPAT_BINFMT_ELF
2357         select HAVE_UID16
2358         ---help---
2359           Include code to run legacy 32-bit programs under a
2360           64-bit kernel. You should likely turn this on, unless you're
2361           100% sure that you don't have any 32-bit programs left.
2362 
2363 config IA32_AOUT
2364         tristate "IA32 a.out support"
2365         depends on IA32_EMULATION
2366         ---help---
2367           Support old a.out binaries in the 32bit emulation.
2368 
2369 config X86_X32
2370         bool "x32 ABI for 64-bit mode"
2371         depends on X86_64 && IA32_EMULATION
2372         ---help---
2373           Include code to run binaries for the x32 native 32-bit ABI
2374           for 64-bit processors.  An x32 process gets access to the
2375           full 64-bit register file and wide data path while leaving
2376           pointers at 32 bits for smaller memory footprint.
2377 
2378           You will need a recent binutils (2.22 or later) with
2379           elf32_x86_64 support enabled to compile a kernel with this
2380           option set.
2381 
2382 config COMPAT
2383         def_bool y
2384         depends on IA32_EMULATION || X86_X32
2385         select ARCH_WANT_OLD_COMPAT_IPC
2386 
2387 if COMPAT
2388 config COMPAT_FOR_U64_ALIGNMENT
2389         def_bool y
2390 
2391 config SYSVIPC_COMPAT
2392         def_bool y
2393         depends on SYSVIPC
2394 
2395 config KEYS_COMPAT
2396         def_bool y
2397         depends on KEYS
2398 endif
2399 
2400 endmenu
2401 
2402 
2403 config HAVE_ATOMIC_IOMAP
2404         def_bool y
2405         depends on X86_32
2406 
2407 config X86_DEV_DMA_OPS
2408         bool
2409         depends on X86_64 || STA2X11
2410 
2411 config X86_DMA_REMAP
2412         bool
2413         depends on STA2X11
2414 
2415 config IOSF_MBI
2416         bool
2417         depends on PCI
2418         ---help---
2419           To be selected by modules requiring access to the Intel OnChip System
2420           Fabric (IOSF) Sideband MailBox Interface (MBI). For MBI platforms
2421           enumerable by PCI.
2422 
2423 source "net/Kconfig"
2424 
2425 source "drivers/Kconfig"
2426 
2427 source "drivers/firmware/Kconfig"
2428 
2429 source "fs/Kconfig"
2430 
2431 source "arch/x86/Kconfig.debug"
2432 
2433 source "security/Kconfig"
2434 
2435 source "crypto/Kconfig"
2436 
2437 source "arch/x86/kvm/Kconfig"
2438 
2439 source "lib/Kconfig"

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