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

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