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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         # Options that are inherently 32-bit kernel only:
 13         select ARCH_WANT_IPC_PARSE_VERSION
 14         select CLKSRC_I8253
 15         select CLONE_BACKWARDS
 16         select HAVE_AOUT
 17         select HAVE_GENERIC_DMA_COHERENT
 18         select MODULES_USE_ELF_REL
 19         select OLD_SIGACTION
 20 
 21 config X86_64
 22         def_bool y
 23         depends on 64BIT
 24         # Options that are inherently 64-bit kernel only:
 25         select ARCH_HAS_GIGANTIC_PAGE
 26         select ARCH_SUPPORTS_INT128
 27         select ARCH_USE_CMPXCHG_LOCKREF
 28         select HAVE_ARCH_SOFT_DIRTY
 29         select MODULES_USE_ELF_RELA
 30         select X86_DEV_DMA_OPS
 31 
 32 #
 33 # Arch settings
 34 #
 35 # ( Note that options that are marked 'if X86_64' could in principle be
 36 #   ported to 32-bit as well. )
 37 #
 38 config X86
 39         def_bool y
 40         #
 41         # Note: keep this list sorted alphabetically
 42         #
 43         select ACPI_LEGACY_TABLES_LOOKUP        if ACPI
 44         select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
 45         select ANON_INODES
 46         select ARCH_CLOCKSOURCE_DATA
 47         select ARCH_DISCARD_MEMBLOCK
 48         select ARCH_HAS_ACPI_TABLE_UPGRADE      if ACPI
 49         select ARCH_HAS_DEVMEM_IS_ALLOWED
 50         select ARCH_HAS_ELF_RANDOMIZE
 51         select ARCH_HAS_FAST_MULTIPLIER
 52         select ARCH_HAS_GCOV_PROFILE_ALL
 53         select ARCH_HAS_KCOV                    if X86_64
 54         select ARCH_HAS_MMIO_FLUSH
 55         select ARCH_HAS_PMEM_API                if X86_64
 56         select ARCH_HAS_SG_CHAIN
 57         select ARCH_HAS_UBSAN_SANITIZE_ALL
 58         select ARCH_HAVE_NMI_SAFE_CMPXCHG
 59         select ARCH_MIGHT_HAVE_ACPI_PDC         if ACPI
 60         select ARCH_MIGHT_HAVE_PC_PARPORT
 61         select ARCH_MIGHT_HAVE_PC_SERIO
 62         select ARCH_SUPPORTS_ATOMIC_RMW
 63         select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
 64         select ARCH_SUPPORTS_NUMA_BALANCING     if X86_64
 65         select ARCH_USE_BUILTIN_BSWAP
 66         select ARCH_USE_QUEUED_RWLOCKS
 67         select ARCH_USE_QUEUED_SPINLOCKS
 68         select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
 69         select ARCH_WANT_FRAME_POINTERS
 70         select ARCH_WANTS_DYNAMIC_TASK_STRUCT
 71         select BUILDTIME_EXTABLE_SORT
 72         select CLKEVT_I8253
 73         select CLOCKSOURCE_VALIDATE_LAST_CYCLE
 74         select CLOCKSOURCE_WATCHDOG
 75         select DCACHE_WORD_ACCESS
 76         select EDAC_ATOMIC_SCRUB
 77         select EDAC_SUPPORT
 78         select GENERIC_CLOCKEVENTS
 79         select GENERIC_CLOCKEVENTS_BROADCAST    if X86_64 || (X86_32 && X86_LOCAL_APIC)
 80         select GENERIC_CLOCKEVENTS_MIN_ADJUST
 81         select GENERIC_CMOS_UPDATE
 82         select GENERIC_CPU_AUTOPROBE
 83         select GENERIC_EARLY_IOREMAP
 84         select GENERIC_FIND_FIRST_BIT
 85         select GENERIC_IOMAP
 86         select GENERIC_IRQ_PROBE
 87         select GENERIC_IRQ_SHOW
 88         select GENERIC_PENDING_IRQ              if SMP
 89         select GENERIC_SMP_IDLE_THREAD
 90         select GENERIC_STRNCPY_FROM_USER
 91         select GENERIC_STRNLEN_USER
 92         select GENERIC_TIME_VSYSCALL
 93         select HAVE_ACPI_APEI                   if ACPI
 94         select HAVE_ACPI_APEI_NMI               if ACPI
 95         select HAVE_ALIGNED_STRUCT_PAGE         if SLUB
 96         select HAVE_ARCH_AUDITSYSCALL
 97         select HAVE_ARCH_HARDENED_USERCOPY
 98         select HAVE_ARCH_HUGE_VMAP              if X86_64 || X86_PAE
 99         select HAVE_ARCH_JUMP_LABEL
100         select HAVE_ARCH_KASAN                  if X86_64 && SPARSEMEM_VMEMMAP
101         select HAVE_ARCH_KGDB
102         select HAVE_ARCH_KMEMCHECK
103         select HAVE_ARCH_MMAP_RND_BITS          if MMU
104         select HAVE_ARCH_MMAP_RND_COMPAT_BITS   if MMU && COMPAT
105         select HAVE_ARCH_SECCOMP_FILTER
106         select HAVE_ARCH_TRACEHOOK
107         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
108         select HAVE_ARCH_VMAP_STACK             if X86_64
109         select HAVE_ARCH_WITHIN_STACK_FRAMES
110         select HAVE_CC_STACKPROTECTOR
111         select HAVE_CMPXCHG_DOUBLE
112         select HAVE_CMPXCHG_LOCAL
113         select HAVE_CONTEXT_TRACKING            if X86_64
114         select HAVE_COPY_THREAD_TLS
115         select HAVE_C_RECORDMCOUNT
116         select HAVE_DEBUG_KMEMLEAK
117         select HAVE_DEBUG_STACKOVERFLOW
118         select HAVE_DMA_API_DEBUG
119         select HAVE_DMA_CONTIGUOUS
120         select HAVE_DYNAMIC_FTRACE
121         select HAVE_DYNAMIC_FTRACE_WITH_REGS
122         select HAVE_EBPF_JIT                    if X86_64
123         select HAVE_EFFICIENT_UNALIGNED_ACCESS
124         select HAVE_EXIT_THREAD
125         select HAVE_FENTRY                      if X86_64
126         select HAVE_FTRACE_MCOUNT_RECORD
127         select HAVE_FUNCTION_GRAPH_TRACER
128         select HAVE_FUNCTION_TRACER
129         select HAVE_GCC_PLUGINS
130         select HAVE_HW_BREAKPOINT
131         select HAVE_IDE
132         select HAVE_IOREMAP_PROT
133         select HAVE_IRQ_EXIT_ON_IRQ_STACK       if X86_64
134         select HAVE_IRQ_TIME_ACCOUNTING
135         select HAVE_KERNEL_BZIP2
136         select HAVE_KERNEL_GZIP
137         select HAVE_KERNEL_LZ4
138         select HAVE_KERNEL_LZMA
139         select HAVE_KERNEL_LZO
140         select HAVE_KERNEL_XZ
141         select HAVE_KPROBES
142         select HAVE_KPROBES_ON_FTRACE
143         select HAVE_KRETPROBES
144         select HAVE_KVM
145         select HAVE_LIVEPATCH                   if X86_64
146         select HAVE_MEMBLOCK
147         select HAVE_MEMBLOCK_NODE_MAP
148         select HAVE_MIXED_BREAKPOINTS_REGS
149         select HAVE_NMI
150         select HAVE_OPROFILE
151         select HAVE_OPTPROBES
152         select HAVE_PCSPKR_PLATFORM
153         select HAVE_PERF_EVENTS
154         select HAVE_PERF_EVENTS_NMI
155         select HAVE_PERF_REGS
156         select HAVE_PERF_USER_STACK_DUMP
157         select HAVE_REGS_AND_STACK_ACCESS_API
158         select HAVE_STACK_VALIDATION            if X86_64
159         select HAVE_SYSCALL_TRACEPOINTS
160         select HAVE_UNSTABLE_SCHED_CLOCK
161         select HAVE_USER_RETURN_NOTIFIER
162         select IRQ_FORCED_THREADING
163         select PERF_EVENTS
164         select RTC_LIB
165         select RTC_MC146818_LIB
166         select SPARSE_IRQ
167         select SRCU
168         select SYSCTL_EXCEPTION_TRACE
169         select THREAD_INFO_IN_TASK
170         select USER_STACKTRACE_SUPPORT
171         select VIRT_TO_BUS
172         select X86_FEATURE_NAMES                if PROC_FS
173 
174 config INSTRUCTION_DECODER
175         def_bool y
176         depends on KPROBES || PERF_EVENTS || UPROBES
177 
178 config OUTPUT_FORMAT
179         string
180         default "elf32-i386" if X86_32
181         default "elf64-x86-64" if X86_64
182 
183 config ARCH_DEFCONFIG
184         string
185         default "arch/x86/configs/i386_defconfig" if X86_32
186         default "arch/x86/configs/x86_64_defconfig" if X86_64
187 
188 config LOCKDEP_SUPPORT
189         def_bool y
190 
191 config STACKTRACE_SUPPORT
192         def_bool y
193 
194 config MMU
195         def_bool y
196 
197 config ARCH_MMAP_RND_BITS_MIN
198         default 28 if 64BIT
199         default 8
200 
201 config ARCH_MMAP_RND_BITS_MAX
202         default 32 if 64BIT
203         default 16
204 
205 config ARCH_MMAP_RND_COMPAT_BITS_MIN
206         default 8
207 
208 config ARCH_MMAP_RND_COMPAT_BITS_MAX
209         default 16
210 
211 config SBUS
212         bool
213 
214 config NEED_DMA_MAP_STATE
215         def_bool y
216         depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
217 
218 config NEED_SG_DMA_LENGTH
219         def_bool y
220 
221 config GENERIC_ISA_DMA
222         def_bool y
223         depends on ISA_DMA_API
224 
225 config GENERIC_BUG
226         def_bool y
227         depends on BUG
228         select GENERIC_BUG_RELATIVE_POINTERS if X86_64
229 
230 config GENERIC_BUG_RELATIVE_POINTERS
231         bool
232 
233 config GENERIC_HWEIGHT
234         def_bool y
235 
236 config ARCH_MAY_HAVE_PC_FDC
237         def_bool y
238         depends on ISA_DMA_API
239 
240 config RWSEM_XCHGADD_ALGORITHM
241         def_bool y
242 
243 config GENERIC_CALIBRATE_DELAY
244         def_bool y
245 
246 config ARCH_HAS_CPU_RELAX
247         def_bool y
248 
249 config ARCH_HAS_CACHE_LINE_SIZE
250         def_bool y
251 
252 config HAVE_SETUP_PER_CPU_AREA
253         def_bool y
254 
255 config NEED_PER_CPU_EMBED_FIRST_CHUNK
256         def_bool y
257 
258 config NEED_PER_CPU_PAGE_FIRST_CHUNK
259         def_bool y
260 
261 config ARCH_HIBERNATION_POSSIBLE
262         def_bool y
263 
264 config ARCH_SUSPEND_POSSIBLE
265         def_bool y
266 
267 config ARCH_WANT_HUGE_PMD_SHARE
268         def_bool y
269 
270 config ARCH_WANT_GENERAL_HUGETLB
271         def_bool y
272 
273 config ZONE_DMA32
274         def_bool y if X86_64
275 
276 config AUDIT_ARCH
277         def_bool y if X86_64
278 
279 config ARCH_SUPPORTS_OPTIMIZED_INLINING
280         def_bool y
281 
282 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
283         def_bool y
284 
285 config KASAN_SHADOW_OFFSET
286         hex
287         depends on KASAN
288         default 0xdffffc0000000000
289 
290 config HAVE_INTEL_TXT
291         def_bool y
292         depends on INTEL_IOMMU && ACPI
293 
294 config X86_32_SMP
295         def_bool y
296         depends on X86_32 && SMP
297 
298 config X86_64_SMP
299         def_bool y
300         depends on X86_64 && SMP
301 
302 config X86_32_LAZY_GS
303         def_bool y
304         depends on X86_32 && !CC_STACKPROTECTOR
305 
306 config ARCH_SUPPORTS_UPROBES
307         def_bool y
308 
309 config FIX_EARLYCON_MEM
310         def_bool y
311 
312 config DEBUG_RODATA
313         def_bool y
314 
315 config PGTABLE_LEVELS
316         int
317         default 4 if X86_64
318         default 3 if X86_PAE
319         default 2
320 
321 source "init/Kconfig"
322 source "kernel/Kconfig.freezer"
323 
324 menu "Processor type and features"
325 
326 config ZONE_DMA
327         bool "DMA memory allocation support" if EXPERT
328         default y
329         help
330           DMA memory allocation support allows devices with less than 32-bit
331           addressing to allocate within the first 16MB of address space.
332           Disable if no such devices will be used.
333 
334           If unsure, say Y.
335 
336 config SMP
337         bool "Symmetric multi-processing support"
338         ---help---
339           This enables support for systems with more than one CPU. If you have
340           a system with only one CPU, say N. If you have a system with more
341           than one CPU, say Y.
342 
343           If you say N here, the kernel will run on uni- and multiprocessor
344           machines, but will use only one CPU of a multiprocessor machine. If
345           you say Y here, the kernel will run on many, but not all,
346           uniprocessor machines. On a uniprocessor machine, the kernel
347           will run faster if you say N here.
348 
349           Note that if you say Y here and choose architecture "586" or
350           "Pentium" under "Processor family", the kernel will not work on 486
351           architectures. Similarly, multiprocessor kernels for the "PPro"
352           architecture may not work on all Pentium based boards.
353 
354           People using multiprocessor machines who say Y here should also say
355           Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
356           Management" code will be disabled if you say Y here.
357 
358           See also <file:Documentation/x86/i386/IO-APIC.txt>,
359           <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
360           <http://www.tldp.org/docs.html#howto>.
361 
362           If you don't know what to do here, say N.
363 
364 config X86_FEATURE_NAMES
365         bool "Processor feature human-readable names" if EMBEDDED
366         default y
367         ---help---
368           This option compiles in a table of x86 feature bits and corresponding
369           names.  This is required to support /proc/cpuinfo and a few kernel
370           messages.  You can disable this to save space, at the expense of
371           making those few kernel messages show numeric feature bits instead.
372 
373           If in doubt, say Y.
374 
375 config X86_FAST_FEATURE_TESTS
376         bool "Fast CPU feature tests" if EMBEDDED
377         default y
378         ---help---
379           Some fast-paths in the kernel depend on the capabilities of the CPU.
380           Say Y here for the kernel to patch in the appropriate code at runtime
381           based on the capabilities of the CPU. The infrastructure for patching
382           code at runtime takes up some additional space; space-constrained
383           embedded systems may wish to say N here to produce smaller, slightly
384           slower code.
385 
386 config X86_X2APIC
387         bool "Support x2apic"
388         depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
389         ---help---
390           This enables x2apic support on CPUs that have this feature.
391 
392           This allows 32-bit apic IDs (so it can support very large systems),
393           and accesses the local apic via MSRs not via mmio.
394 
395           If you don't know what to do here, say N.
396 
397 config X86_MPPARSE
398         bool "Enable MPS table" if ACPI || SFI
399         default y
400         depends on X86_LOCAL_APIC
401         ---help---
402           For old smp systems that do not have proper acpi support. Newer systems
403           (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
404 
405 config X86_BIGSMP
406         bool "Support for big SMP systems with more than 8 CPUs"
407         depends on X86_32 && SMP
408         ---help---
409           This option is needed for the systems that have more than 8 CPUs
410 
411 config GOLDFISH
412        def_bool y
413        depends on X86_GOLDFISH
414 
415 config INTEL_RDT_A
416         bool "Intel Resource Director Technology Allocation support"
417         default n
418         depends on X86 && CPU_SUP_INTEL
419         select KERNFS
420         help
421           Select to enable resource allocation which is a sub-feature of
422           Intel Resource Director Technology(RDT). More information about
423           RDT can be found in the Intel x86 Architecture Software
424           Developer Manual.
425 
426           Say N if unsure.
427 
428 if X86_32
429 config X86_EXTENDED_PLATFORM
430         bool "Support for extended (non-PC) x86 platforms"
431         default y
432         ---help---
433           If you disable this option then the kernel will only support
434           standard PC platforms. (which covers the vast majority of
435           systems out there.)
436 
437           If you enable this option then you'll be able to select support
438           for the following (non-PC) 32 bit x86 platforms:
439                 Goldfish (Android emulator)
440                 AMD Elan
441                 RDC R-321x SoC
442                 SGI 320/540 (Visual Workstation)
443                 STA2X11-based (e.g. Northville)
444                 Moorestown MID devices
445 
446           If you have one of these systems, or if you want to build a
447           generic distribution kernel, say Y here - otherwise say N.
448 endif
449 
450 if X86_64
451 config X86_EXTENDED_PLATFORM
452         bool "Support for extended (non-PC) x86 platforms"
453         default y
454         ---help---
455           If you disable this option then the kernel will only support
456           standard PC platforms. (which covers the vast majority of
457           systems out there.)
458 
459           If you enable this option then you'll be able to select support
460           for the following (non-PC) 64 bit x86 platforms:
461                 Numascale NumaChip
462                 ScaleMP vSMP
463                 SGI Ultraviolet
464 
465           If you have one of these systems, or if you want to build a
466           generic distribution kernel, say Y here - otherwise say N.
467 endif
468 # This is an alphabetically sorted list of 64 bit extended platforms
469 # Please maintain the alphabetic order if and when there are additions
470 config X86_NUMACHIP
471         bool "Numascale NumaChip"
472         depends on X86_64
473         depends on X86_EXTENDED_PLATFORM
474         depends on NUMA
475         depends on SMP
476         depends on X86_X2APIC
477         depends on PCI_MMCONFIG
478         ---help---
479           Adds support for Numascale NumaChip large-SMP systems. Needed to
480           enable more than ~168 cores.
481           If you don't have one of these, you should say N here.
482 
483 config X86_VSMP
484         bool "ScaleMP vSMP"
485         select HYPERVISOR_GUEST
486         select PARAVIRT
487         depends on X86_64 && PCI
488         depends on X86_EXTENDED_PLATFORM
489         depends on SMP
490         ---help---
491           Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
492           supposed to run on these EM64T-based machines.  Only choose this option
493           if you have one of these machines.
494 
495 config X86_UV
496         bool "SGI Ultraviolet"
497         depends on X86_64
498         depends on X86_EXTENDED_PLATFORM
499         depends on NUMA
500         depends on EFI
501         depends on X86_X2APIC
502         depends on PCI
503         ---help---
504           This option is needed in order to support SGI Ultraviolet systems.
505           If you don't have one of these, you should say N here.
506 
507 # Following is an alphabetically sorted list of 32 bit extended platforms
508 # Please maintain the alphabetic order if and when there are additions
509 
510 config X86_GOLDFISH
511        bool "Goldfish (Virtual Platform)"
512        depends on X86_EXTENDED_PLATFORM
513        ---help---
514          Enable support for the Goldfish virtual platform used primarily
515          for Android development. Unless you are building for the Android
516          Goldfish emulator say N here.
517 
518 config X86_INTEL_CE
519         bool "CE4100 TV platform"
520         depends on PCI
521         depends on PCI_GODIRECT
522         depends on X86_IO_APIC
523         depends on X86_32
524         depends on X86_EXTENDED_PLATFORM
525         select X86_REBOOTFIXUPS
526         select OF
527         select OF_EARLY_FLATTREE
528         ---help---
529           Select for the Intel CE media processor (CE4100) SOC.
530           This option compiles in support for the CE4100 SOC for settop
531           boxes and media devices.
532 
533 config X86_INTEL_MID
534         bool "Intel MID platform support"
535         depends on X86_EXTENDED_PLATFORM
536         depends on X86_PLATFORM_DEVICES
537         depends on PCI
538         depends on X86_64 || (PCI_GOANY && X86_32)
539         depends on X86_IO_APIC
540         select SFI
541         select I2C
542         select DW_APB_TIMER
543         select APB_TIMER
544         select INTEL_SCU_IPC
545         select MFD_INTEL_MSIC
546         ---help---
547           Select to build a kernel capable of supporting Intel MID (Mobile
548           Internet Device) platform systems which do not have the PCI legacy
549           interfaces. If you are building for a PC class system say N here.
550 
551           Intel MID platforms are based on an Intel processor and chipset which
552           consume less power than most of the x86 derivatives.
553 
554 config X86_INTEL_QUARK
555         bool "Intel Quark platform support"
556         depends on X86_32
557         depends on X86_EXTENDED_PLATFORM
558         depends on X86_PLATFORM_DEVICES
559         depends on X86_TSC
560         depends on PCI
561         depends on PCI_GOANY
562         depends on X86_IO_APIC
563         select IOSF_MBI
564         select INTEL_IMR
565         select COMMON_CLK
566         ---help---
567           Select to include support for Quark X1000 SoC.
568           Say Y here if you have a Quark based system such as the Arduino
569           compatible Intel Galileo.
570 
571 config X86_INTEL_LPSS
572         bool "Intel Low Power Subsystem Support"
573         depends on X86 && ACPI
574         select COMMON_CLK
575         select PINCTRL
576         select IOSF_MBI
577         ---help---
578           Select to build support for Intel Low Power Subsystem such as
579           found on Intel Lynxpoint PCH. Selecting this option enables
580           things like clock tree (common clock framework) and pincontrol
581           which are needed by the LPSS peripheral drivers.
582 
583 config X86_AMD_PLATFORM_DEVICE
584         bool "AMD ACPI2Platform devices support"
585         depends on ACPI
586         select COMMON_CLK
587         select PINCTRL
588         ---help---
589           Select to interpret AMD specific ACPI device to platform device
590           such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
591           I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
592           implemented under PINCTRL subsystem.
593 
594 config IOSF_MBI
595         tristate "Intel SoC IOSF Sideband support for SoC platforms"
596         depends on PCI
597         ---help---
598           This option enables sideband register access support for Intel SoC
599           platforms. On these platforms the IOSF sideband is used in lieu of
600           MSR's for some register accesses, mostly but not limited to thermal
601           and power. Drivers may query the availability of this device to
602           determine if they need the sideband in order to work on these
603           platforms. The sideband is available on the following SoC products.
604           This list is not meant to be exclusive.
605            - BayTrail
606            - Braswell
607            - Quark
608 
609           You should say Y if you are running a kernel on one of these SoC's.
610 
611 config IOSF_MBI_DEBUG
612         bool "Enable IOSF sideband access through debugfs"
613         depends on IOSF_MBI && DEBUG_FS
614         ---help---
615           Select this option to expose the IOSF sideband access registers (MCR,
616           MDR, MCRX) through debugfs to write and read register information from
617           different units on the SoC. This is most useful for obtaining device
618           state information for debug and analysis. As this is a general access
619           mechanism, users of this option would have specific knowledge of the
620           device they want to access.
621 
622           If you don't require the option or are in doubt, say N.
623 
624 config X86_RDC321X
625         bool "RDC R-321x SoC"
626         depends on X86_32
627         depends on X86_EXTENDED_PLATFORM
628         select M486
629         select X86_REBOOTFIXUPS
630         ---help---
631           This option is needed for RDC R-321x system-on-chip, also known
632           as R-8610-(G).
633           If you don't have one of these chips, you should say N here.
634 
635 config X86_32_NON_STANDARD
636         bool "Support non-standard 32-bit SMP architectures"
637         depends on X86_32 && SMP
638         depends on X86_EXTENDED_PLATFORM
639         ---help---
640           This option compiles in the bigsmp and STA2X11 default
641           subarchitectures.  It is intended for a generic binary
642           kernel. If you select them all, kernel will probe it one by
643           one and will fallback to default.
644 
645 # Alphabetically sorted list of Non standard 32 bit platforms
646 
647 config X86_SUPPORTS_MEMORY_FAILURE
648         def_bool y
649         # MCE code calls memory_failure():
650         depends on X86_MCE
651         # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
652         # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
653         depends on X86_64 || !SPARSEMEM
654         select ARCH_SUPPORTS_MEMORY_FAILURE
655 
656 config STA2X11
657         bool "STA2X11 Companion Chip Support"
658         depends on X86_32_NON_STANDARD && PCI
659         select X86_DEV_DMA_OPS
660         select X86_DMA_REMAP
661         select SWIOTLB
662         select MFD_STA2X11
663         select GPIOLIB
664         default n
665         ---help---
666           This adds support for boards based on the STA2X11 IO-Hub,
667           a.k.a. "ConneXt". The chip is used in place of the standard
668           PC chipset, so all "standard" peripherals are missing. If this
669           option is selected the kernel will still be able to boot on
670           standard PC machines.
671 
672 config X86_32_IRIS
673         tristate "Eurobraille/Iris poweroff module"
674         depends on X86_32
675         ---help---
676           The Iris machines from EuroBraille do not have APM or ACPI support
677           to shut themselves down properly.  A special I/O sequence is
678           needed to do so, which is what this module does at
679           kernel shutdown.
680 
681           This is only for Iris machines from EuroBraille.
682 
683           If unused, say N.
684 
685 config SCHED_OMIT_FRAME_POINTER
686         def_bool y
687         prompt "Single-depth WCHAN output"
688         depends on X86
689         ---help---
690           Calculate simpler /proc/<PID>/wchan values. If this option
691           is disabled then wchan values will recurse back to the
692           caller function. This provides more accurate wchan values,
693           at the expense of slightly more scheduling overhead.
694 
695           If in doubt, say "Y".
696 
697 menuconfig HYPERVISOR_GUEST
698         bool "Linux guest support"
699         ---help---
700           Say Y here to enable options for running Linux under various hyper-
701           visors. This option enables basic hypervisor detection and platform
702           setup.
703 
704           If you say N, all options in this submenu will be skipped and
705           disabled, and Linux guest support won't be built in.
706 
707 if HYPERVISOR_GUEST
708 
709 config PARAVIRT
710         bool "Enable paravirtualization code"
711         ---help---
712           This changes the kernel so it can modify itself when it is run
713           under a hypervisor, potentially improving performance significantly
714           over full virtualization.  However, when run without a hypervisor
715           the kernel is theoretically slower and slightly larger.
716 
717 config PARAVIRT_DEBUG
718         bool "paravirt-ops debugging"
719         depends on PARAVIRT && DEBUG_KERNEL
720         ---help---
721           Enable to debug paravirt_ops internals.  Specifically, BUG if
722           a paravirt_op is missing when it is called.
723 
724 config PARAVIRT_SPINLOCKS
725         bool "Paravirtualization layer for spinlocks"
726         depends on PARAVIRT && SMP
727         ---help---
728           Paravirtualized spinlocks allow a pvops backend to replace the
729           spinlock implementation with something virtualization-friendly
730           (for example, block the virtual CPU rather than spinning).
731 
732           It has a minimal impact on native kernels and gives a nice performance
733           benefit on paravirtualized KVM / Xen kernels.
734 
735           If you are unsure how to answer this question, answer Y.
736 
737 config QUEUED_LOCK_STAT
738         bool "Paravirt queued spinlock statistics"
739         depends on PARAVIRT_SPINLOCKS && DEBUG_FS
740         ---help---
741           Enable the collection of statistical data on the slowpath
742           behavior of paravirtualized queued spinlocks and report
743           them on debugfs.
744 
745 source "arch/x86/xen/Kconfig"
746 
747 config KVM_GUEST
748         bool "KVM Guest support (including kvmclock)"
749         depends on PARAVIRT
750         select PARAVIRT_CLOCK
751         default y
752         ---help---
753           This option enables various optimizations for running under the KVM
754           hypervisor. It includes a paravirtualized clock, so that instead
755           of relying on a PIT (or probably other) emulation by the
756           underlying device model, the host provides the guest with
757           timing infrastructure such as time of day, and system time
758 
759 config KVM_DEBUG_FS
760         bool "Enable debug information for KVM Guests in debugfs"
761         depends on KVM_GUEST && DEBUG_FS
762         default n
763         ---help---
764           This option enables collection of various statistics for KVM guest.
765           Statistics are displayed in debugfs filesystem. Enabling this option
766           may incur significant overhead.
767 
768 source "arch/x86/lguest/Kconfig"
769 
770 config PARAVIRT_TIME_ACCOUNTING
771         bool "Paravirtual steal time accounting"
772         depends on PARAVIRT
773         default n
774         ---help---
775           Select this option to enable fine granularity task steal time
776           accounting. Time spent executing other tasks in parallel with
777           the current vCPU is discounted from the vCPU power. To account for
778           that, there can be a small performance impact.
779 
780           If in doubt, say N here.
781 
782 config PARAVIRT_CLOCK
783         bool
784 
785 endif #HYPERVISOR_GUEST
786 
787 config NO_BOOTMEM
788         def_bool y
789 
790 source "arch/x86/Kconfig.cpu"
791 
792 config HPET_TIMER
793         def_bool X86_64
794         prompt "HPET Timer Support" if X86_32
795         ---help---
796           Use the IA-PC HPET (High Precision Event Timer) to manage
797           time in preference to the PIT and RTC, if a HPET is
798           present.
799           HPET is the next generation timer replacing legacy 8254s.
800           The HPET provides a stable time base on SMP
801           systems, unlike the TSC, but it is more expensive to access,
802           as it is off-chip.  The interface used is documented
803           in the HPET spec, revision 1.
804 
805           You can safely choose Y here.  However, HPET will only be
806           activated if the platform and the BIOS support this feature.
807           Otherwise the 8254 will be used for timing services.
808 
809           Choose N to continue using the legacy 8254 timer.
810 
811 config HPET_EMULATE_RTC
812         def_bool y
813         depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
814 
815 config APB_TIMER
816        def_bool y if X86_INTEL_MID
817        prompt "Intel MID APB Timer Support" if X86_INTEL_MID
818        select DW_APB_TIMER
819        depends on X86_INTEL_MID && SFI
820        help
821          APB timer is the replacement for 8254, HPET on X86 MID platforms.
822          The APBT provides a stable time base on SMP
823          systems, unlike the TSC, but it is more expensive to access,
824          as it is off-chip. APB timers are always running regardless of CPU
825          C states, they are used as per CPU clockevent device when possible.
826 
827 # Mark as expert because too many people got it wrong.
828 # The code disables itself when not needed.
829 config DMI
830         default y
831         select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
832         bool "Enable DMI scanning" if EXPERT
833         ---help---
834           Enabled scanning of DMI to identify machine quirks. Say Y
835           here unless you have verified that your setup is not
836           affected by entries in the DMI blacklist. Required by PNP
837           BIOS code.
838 
839 config GART_IOMMU
840         bool "Old AMD GART IOMMU support"
841         select SWIOTLB
842         depends on X86_64 && PCI && AMD_NB
843         ---help---
844           Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
845           GART based hardware IOMMUs.
846 
847           The GART supports full DMA access for devices with 32-bit access
848           limitations, on systems with more than 3 GB. This is usually needed
849           for USB, sound, many IDE/SATA chipsets and some other devices.
850 
851           Newer systems typically have a modern AMD IOMMU, supported via
852           the CONFIG_AMD_IOMMU=y config option.
853 
854           In normal configurations this driver is only active when needed:
855           there's more than 3 GB of memory and the system contains a
856           32-bit limited device.
857 
858           If unsure, say Y.
859 
860 config CALGARY_IOMMU
861         bool "IBM Calgary IOMMU support"
862         select SWIOTLB
863         depends on X86_64 && PCI
864         ---help---
865           Support for hardware IOMMUs in IBM's xSeries x366 and x460
866           systems. Needed to run systems with more than 3GB of memory
867           properly with 32-bit PCI devices that do not support DAC
868           (Double Address Cycle). Calgary also supports bus level
869           isolation, where all DMAs pass through the IOMMU.  This
870           prevents them from going anywhere except their intended
871           destination. This catches hard-to-find kernel bugs and
872           mis-behaving drivers and devices that do not use the DMA-API
873           properly to set up their DMA buffers.  The IOMMU can be
874           turned off at boot time with the iommu=off parameter.
875           Normally the kernel will make the right choice by itself.
876           If unsure, say Y.
877 
878 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
879         def_bool y
880         prompt "Should Calgary be enabled by default?"
881         depends on CALGARY_IOMMU
882         ---help---
883           Should Calgary be enabled by default? if you choose 'y', Calgary
884           will be used (if it exists). If you choose 'n', Calgary will not be
885           used even if it exists. If you choose 'n' and would like to use
886           Calgary anyway, pass 'iommu=calgary' on the kernel command line.
887           If unsure, say Y.
888 
889 # need this always selected by IOMMU for the VIA workaround
890 config SWIOTLB
891         def_bool y if X86_64
892         ---help---
893           Support for software bounce buffers used on x86-64 systems
894           which don't have a hardware IOMMU. Using this PCI devices
895           which can only access 32-bits of memory can be used on systems
896           with more than 3 GB of memory.
897           If unsure, say Y.
898 
899 config IOMMU_HELPER
900         def_bool y
901         depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
902 
903 config MAXSMP
904         bool "Enable Maximum number of SMP Processors and NUMA Nodes"
905         depends on X86_64 && SMP && DEBUG_KERNEL
906         select CPUMASK_OFFSTACK
907         ---help---
908           Enable maximum number of CPUS and NUMA Nodes for this architecture.
909           If unsure, say N.
910 
911 config NR_CPUS
912         int "Maximum number of CPUs" if SMP && !MAXSMP
913         range 2 8 if SMP && X86_32 && !X86_BIGSMP
914         range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
915         range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
916         default "1" if !SMP
917         default "8192" if MAXSMP
918         default "32" if SMP && X86_BIGSMP
919         default "8" if SMP && X86_32
920         default "64" if SMP
921         ---help---
922           This allows you to specify the maximum number of CPUs which this
923           kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
924           supported value is 8192, otherwise the maximum value is 512.  The
925           minimum value which makes sense is 2.
926 
927           This is purely to save memory - each supported CPU adds
928           approximately eight kilobytes to the kernel image.
929 
930 config SCHED_SMT
931         bool "SMT (Hyperthreading) scheduler support"
932         depends on SMP
933         ---help---
934           SMT scheduler support improves the CPU scheduler's decision making
935           when dealing with Intel Pentium 4 chips with HyperThreading at a
936           cost of slightly increased overhead in some places. If unsure say
937           N here.
938 
939 config SCHED_MC
940         def_bool y
941         prompt "Multi-core scheduler support"
942         depends on SMP
943         ---help---
944           Multi-core scheduler support improves the CPU scheduler's decision
945           making when dealing with multi-core CPU chips at a cost of slightly
946           increased overhead in some places. If unsure say N here.
947 
948 config SCHED_MC_PRIO
949         bool "CPU core priorities scheduler support"
950         depends on SCHED_MC && CPU_SUP_INTEL
951         select X86_INTEL_PSTATE
952         select CPU_FREQ
953         default y
954         ---help---
955           Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
956           core ordering determined at manufacturing time, which allows
957           certain cores to reach higher turbo frequencies (when running
958           single threaded workloads) than others.
959 
960           Enabling this kernel feature teaches the scheduler about
961           the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
962           scheduler's CPU selection logic accordingly, so that higher
963           overall system performance can be achieved.
964 
965           This feature will have no effect on CPUs without this feature.
966 
967           If unsure say Y here.
968 
969 source "kernel/Kconfig.preempt"
970 
971 config UP_LATE_INIT
972        def_bool y
973        depends on !SMP && X86_LOCAL_APIC
974 
975 config X86_UP_APIC
976         bool "Local APIC support on uniprocessors" if !PCI_MSI
977         default PCI_MSI
978         depends on X86_32 && !SMP && !X86_32_NON_STANDARD
979         ---help---
980           A local APIC (Advanced Programmable Interrupt Controller) is an
981           integrated interrupt controller in the CPU. If you have a single-CPU
982           system which has a processor with a local APIC, you can say Y here to
983           enable and use it. If you say Y here even though your machine doesn't
984           have a local APIC, then the kernel will still run with no slowdown at
985           all. The local APIC supports CPU-generated self-interrupts (timer,
986           performance counters), and the NMI watchdog which detects hard
987           lockups.
988 
989 config X86_UP_IOAPIC
990         bool "IO-APIC support on uniprocessors"
991         depends on X86_UP_APIC
992         ---help---
993           An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
994           SMP-capable replacement for PC-style interrupt controllers. Most
995           SMP systems and many recent uniprocessor systems have one.
996 
997           If you have a single-CPU system with an IO-APIC, you can say Y here
998           to use it. If you say Y here even though your machine doesn't have
999           an IO-APIC, then the kernel will still run with no slowdown at all.
1000 
1001 config X86_LOCAL_APIC
1002         def_bool y
1003         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1004         select IRQ_DOMAIN_HIERARCHY
1005         select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1006 
1007 config X86_IO_APIC
1008         def_bool y
1009         depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1010 
1011 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1012         bool "Reroute for broken boot IRQs"
1013         depends on X86_IO_APIC
1014         ---help---
1015           This option enables a workaround that fixes a source of
1016           spurious interrupts. This is recommended when threaded
1017           interrupt handling is used on systems where the generation of
1018           superfluous "boot interrupts" cannot be disabled.
1019 
1020           Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1021           entry in the chipset's IO-APIC is masked (as, e.g. the RT
1022           kernel does during interrupt handling). On chipsets where this
1023           boot IRQ generation cannot be disabled, this workaround keeps
1024           the original IRQ line masked so that only the equivalent "boot
1025           IRQ" is delivered to the CPUs. The workaround also tells the
1026           kernel to set up the IRQ handler on the boot IRQ line. In this
1027           way only one interrupt is delivered to the kernel. Otherwise
1028           the spurious second interrupt may cause the kernel to bring
1029           down (vital) interrupt lines.
1030 
1031           Only affects "broken" chipsets. Interrupt sharing may be
1032           increased on these systems.
1033 
1034 config X86_MCE
1035         bool "Machine Check / overheating reporting"
1036         select GENERIC_ALLOCATOR
1037         default y
1038         ---help---
1039           Machine Check support allows the processor to notify the
1040           kernel if it detects a problem (e.g. overheating, data corruption).
1041           The action the kernel takes depends on the severity of the problem,
1042           ranging from warning messages to halting the machine.
1043 
1044 config X86_MCE_INTEL
1045         def_bool y
1046         prompt "Intel MCE features"
1047         depends on X86_MCE && X86_LOCAL_APIC
1048         ---help---
1049            Additional support for intel specific MCE features such as
1050            the thermal monitor.
1051 
1052 config X86_MCE_AMD
1053         def_bool y
1054         prompt "AMD MCE features"
1055         depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1056         ---help---
1057            Additional support for AMD specific MCE features such as
1058            the DRAM Error Threshold.
1059 
1060 config X86_ANCIENT_MCE
1061         bool "Support for old Pentium 5 / WinChip machine checks"
1062         depends on X86_32 && X86_MCE
1063         ---help---
1064           Include support for machine check handling on old Pentium 5 or WinChip
1065           systems. These typically need to be enabled explicitly on the command
1066           line.
1067 
1068 config X86_MCE_THRESHOLD
1069         depends on X86_MCE_AMD || X86_MCE_INTEL
1070         def_bool y
1071 
1072 config X86_MCE_INJECT
1073         depends on X86_MCE
1074         tristate "Machine check injector support"
1075         ---help---
1076           Provide support for injecting machine checks for testing purposes.
1077           If you don't know what a machine check is and you don't do kernel
1078           QA it is safe to say n.
1079 
1080 config X86_THERMAL_VECTOR
1081         def_bool y
1082         depends on X86_MCE_INTEL
1083 
1084 source "arch/x86/events/Kconfig"
1085 
1086 config X86_LEGACY_VM86
1087         bool "Legacy VM86 support"
1088         default n
1089         depends on X86_32
1090         ---help---
1091           This option allows user programs to put the CPU into V8086
1092           mode, which is an 80286-era approximation of 16-bit real mode.
1093 
1094           Some very old versions of X and/or vbetool require this option
1095           for user mode setting.  Similarly, DOSEMU will use it if
1096           available to accelerate real mode DOS programs.  However, any
1097           recent version of DOSEMU, X, or vbetool should be fully
1098           functional even without kernel VM86 support, as they will all
1099           fall back to software emulation. Nevertheless, if you are using
1100           a 16-bit DOS program where 16-bit performance matters, vm86
1101           mode might be faster than emulation and you might want to
1102           enable this option.
1103 
1104           Note that any app that works on a 64-bit kernel is unlikely to
1105           need this option, as 64-bit kernels don't, and can't, support
1106           V8086 mode. This option is also unrelated to 16-bit protected
1107           mode and is not needed to run most 16-bit programs under Wine.
1108 
1109           Enabling this option increases the complexity of the kernel
1110           and slows down exception handling a tiny bit.
1111 
1112           If unsure, say N here.
1113 
1114 config VM86
1115        bool
1116        default X86_LEGACY_VM86
1117 
1118 config X86_16BIT
1119         bool "Enable support for 16-bit segments" if EXPERT
1120         default y
1121         depends on MODIFY_LDT_SYSCALL
1122         ---help---
1123           This option is required by programs like Wine to run 16-bit
1124           protected mode legacy code on x86 processors.  Disabling
1125           this option saves about 300 bytes on i386, or around 6K text
1126           plus 16K runtime memory on x86-64,
1127 
1128 config X86_ESPFIX32
1129         def_bool y
1130         depends on X86_16BIT && X86_32
1131 
1132 config X86_ESPFIX64
1133         def_bool y
1134         depends on X86_16BIT && X86_64
1135 
1136 config X86_VSYSCALL_EMULATION
1137        bool "Enable vsyscall emulation" if EXPERT
1138        default y
1139        depends on X86_64
1140        ---help---
1141          This enables emulation of the legacy vsyscall page.  Disabling
1142          it is roughly equivalent to booting with vsyscall=none, except
1143          that it will also disable the helpful warning if a program
1144          tries to use a vsyscall.  With this option set to N, offending
1145          programs will just segfault, citing addresses of the form
1146          0xffffffffff600?00.
1147 
1148          This option is required by many programs built before 2013, and
1149          care should be used even with newer programs if set to N.
1150 
1151          Disabling this option saves about 7K of kernel size and
1152          possibly 4K of additional runtime pagetable memory.
1153 
1154 config TOSHIBA
1155         tristate "Toshiba Laptop support"
1156         depends on X86_32
1157         ---help---
1158           This adds a driver to safely access the System Management Mode of
1159           the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1160           not work on models with a Phoenix BIOS. The System Management Mode
1161           is used to set the BIOS and power saving options on Toshiba portables.
1162 
1163           For information on utilities to make use of this driver see the
1164           Toshiba Linux utilities web site at:
1165           <http://www.buzzard.org.uk/toshiba/>.
1166 
1167           Say Y if you intend to run this kernel on a Toshiba portable.
1168           Say N otherwise.
1169 
1170 config I8K
1171         tristate "Dell i8k legacy laptop support"
1172         select HWMON
1173         select SENSORS_DELL_SMM
1174         ---help---
1175           This option enables legacy /proc/i8k userspace interface in hwmon
1176           dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1177           temperature and allows controlling fan speeds of Dell laptops via
1178           System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1179           it reports also power and hotkey status. For fan speed control is
1180           needed userspace package i8kutils.
1181 
1182           Say Y if you intend to run this kernel on old Dell laptops or want to
1183           use userspace package i8kutils.
1184           Say N otherwise.
1185 
1186 config X86_REBOOTFIXUPS
1187         bool "Enable X86 board specific fixups for reboot"
1188         depends on X86_32
1189         ---help---
1190           This enables chipset and/or board specific fixups to be done
1191           in order to get reboot to work correctly. This is only needed on
1192           some combinations of hardware and BIOS. The symptom, for which
1193           this config is intended, is when reboot ends with a stalled/hung
1194           system.
1195 
1196           Currently, the only fixup is for the Geode machines using
1197           CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1198 
1199           Say Y if you want to enable the fixup. Currently, it's safe to
1200           enable this option even if you don't need it.
1201           Say N otherwise.
1202 
1203 config MICROCODE
1204         bool "CPU microcode loading support"
1205         default y
1206         depends on CPU_SUP_AMD || CPU_SUP_INTEL
1207         select FW_LOADER
1208         ---help---
1209           If you say Y here, you will be able to update the microcode on
1210           Intel and AMD processors. The Intel support is for the IA32 family,
1211           e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1212           AMD support is for families 0x10 and later. You will obviously need
1213           the actual microcode binary data itself which is not shipped with
1214           the Linux kernel.
1215 
1216           The preferred method to load microcode from a detached initrd is described
1217           in Documentation/x86/early-microcode.txt. For that you need to enable
1218           CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1219           initrd for microcode blobs.
1220 
1221           In addition, you can build-in the microcode into the kernel. For that you
1222           need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1223           to the CONFIG_EXTRA_FIRMWARE config option.
1224 
1225 config MICROCODE_INTEL
1226         bool "Intel microcode loading support"
1227         depends on MICROCODE
1228         default MICROCODE
1229         select FW_LOADER
1230         ---help---
1231           This options enables microcode patch loading support for Intel
1232           processors.
1233 
1234           For the current Intel microcode data package go to
1235           <https://downloadcenter.intel.com> and search for
1236           'Linux Processor Microcode Data File'.
1237 
1238 config MICROCODE_AMD
1239         bool "AMD microcode loading support"
1240         depends on MICROCODE
1241         select FW_LOADER
1242         ---help---
1243           If you select this option, microcode patch loading support for AMD
1244           processors will be enabled.
1245 
1246 config MICROCODE_OLD_INTERFACE
1247         def_bool y
1248         depends on MICROCODE
1249 
1250 config X86_MSR
1251         tristate "/dev/cpu/*/msr - Model-specific register support"
1252         ---help---
1253           This device gives privileged processes access to the x86
1254           Model-Specific Registers (MSRs).  It is a character device with
1255           major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1256           MSR accesses are directed to a specific CPU on multi-processor
1257           systems.
1258 
1259 config X86_CPUID
1260         tristate "/dev/cpu/*/cpuid - CPU information support"
1261         ---help---
1262           This device gives processes access to the x86 CPUID instruction to
1263           be executed on a specific processor.  It is a character device
1264           with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1265           /dev/cpu/31/cpuid.
1266 
1267 choice
1268         prompt "High Memory Support"
1269         default HIGHMEM4G
1270         depends on X86_32
1271 
1272 config NOHIGHMEM
1273         bool "off"
1274         ---help---
1275           Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1276           However, the address space of 32-bit x86 processors is only 4
1277           Gigabytes large. That means that, if you have a large amount of
1278           physical memory, not all of it can be "permanently mapped" by the
1279           kernel. The physical memory that's not permanently mapped is called
1280           "high memory".
1281 
1282           If you are compiling a kernel which will never run on a machine with
1283           more than 1 Gigabyte total physical RAM, answer "off" here (default
1284           choice and suitable for most users). This will result in a "3GB/1GB"
1285           split: 3GB are mapped so that each process sees a 3GB virtual memory
1286           space and the remaining part of the 4GB virtual memory space is used
1287           by the kernel to permanently map as much physical memory as
1288           possible.
1289 
1290           If the machine has between 1 and 4 Gigabytes physical RAM, then
1291           answer "4GB" here.
1292 
1293           If more than 4 Gigabytes is used then answer "64GB" here. This
1294           selection turns Intel PAE (Physical Address Extension) mode on.
1295           PAE implements 3-level paging on IA32 processors. PAE is fully
1296           supported by Linux, PAE mode is implemented on all recent Intel
1297           processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1298           then the kernel will not boot on CPUs that don't support PAE!
1299 
1300           The actual amount of total physical memory will either be
1301           auto detected or can be forced by using a kernel command line option
1302           such as "mem=256M". (Try "man bootparam" or see the documentation of
1303           your boot loader (lilo or loadlin) about how to pass options to the
1304           kernel at boot time.)
1305 
1306           If unsure, say "off".
1307 
1308 config HIGHMEM4G
1309         bool "4GB"
1310         ---help---
1311           Select this if you have a 32-bit processor and between 1 and 4
1312           gigabytes of physical RAM.
1313 
1314 config HIGHMEM64G
1315         bool "64GB"
1316         depends on !M486
1317         select X86_PAE
1318         ---help---
1319           Select this if you have a 32-bit processor and more than 4
1320           gigabytes of physical RAM.
1321 
1322 endchoice
1323 
1324 choice
1325         prompt "Memory split" if EXPERT
1326         default VMSPLIT_3G
1327         depends on X86_32
1328         ---help---
1329           Select the desired split between kernel and user memory.
1330 
1331           If the address range available to the kernel is less than the
1332           physical memory installed, the remaining memory will be available
1333           as "high memory". Accessing high memory is a little more costly
1334           than low memory, as it needs to be mapped into the kernel first.
1335           Note that increasing the kernel address space limits the range
1336           available to user programs, making the address space there
1337           tighter.  Selecting anything other than the default 3G/1G split
1338           will also likely make your kernel incompatible with binary-only
1339           kernel modules.
1340 
1341           If you are not absolutely sure what you are doing, leave this
1342           option alone!
1343 
1344         config VMSPLIT_3G
1345                 bool "3G/1G user/kernel split"
1346         config VMSPLIT_3G_OPT
1347                 depends on !X86_PAE
1348                 bool "3G/1G user/kernel split (for full 1G low memory)"
1349         config VMSPLIT_2G
1350                 bool "2G/2G user/kernel split"
1351         config VMSPLIT_2G_OPT
1352                 depends on !X86_PAE
1353                 bool "2G/2G user/kernel split (for full 2G low memory)"
1354         config VMSPLIT_1G
1355                 bool "1G/3G user/kernel split"
1356 endchoice
1357 
1358 config PAGE_OFFSET
1359         hex
1360         default 0xB0000000 if VMSPLIT_3G_OPT
1361         default 0x80000000 if VMSPLIT_2G
1362         default 0x78000000 if VMSPLIT_2G_OPT
1363         default 0x40000000 if VMSPLIT_1G
1364         default 0xC0000000
1365         depends on X86_32
1366 
1367 config HIGHMEM
1368         def_bool y
1369         depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1370 
1371 config X86_PAE
1372         bool "PAE (Physical Address Extension) Support"
1373         depends on X86_32 && !HIGHMEM4G
1374         select SWIOTLB
1375         ---help---
1376           PAE is required for NX support, and furthermore enables
1377           larger swapspace support for non-overcommit purposes. It
1378           has the cost of more pagetable lookup overhead, and also
1379           consumes more pagetable space per process.
1380 
1381 config ARCH_PHYS_ADDR_T_64BIT
1382         def_bool y
1383         depends on X86_64 || X86_PAE
1384 
1385 config ARCH_DMA_ADDR_T_64BIT
1386         def_bool y
1387         depends on X86_64 || HIGHMEM64G
1388 
1389 config X86_DIRECT_GBPAGES
1390         def_bool y
1391         depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1392         ---help---
1393           Certain kernel features effectively disable kernel
1394           linear 1 GB mappings (even if the CPU otherwise
1395           supports them), so don't confuse the user by printing
1396           that we have them enabled.
1397 
1398 # Common NUMA Features
1399 config NUMA
1400         bool "Numa Memory Allocation and Scheduler Support"
1401         depends on SMP
1402         depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1403         default y if X86_BIGSMP
1404         ---help---
1405           Enable NUMA (Non Uniform Memory Access) support.
1406 
1407           The kernel will try to allocate memory used by a CPU on the
1408           local memory controller of the CPU and add some more
1409           NUMA awareness to the kernel.
1410 
1411           For 64-bit this is recommended if the system is Intel Core i7
1412           (or later), AMD Opteron, or EM64T NUMA.
1413 
1414           For 32-bit this is only needed if you boot a 32-bit
1415           kernel on a 64-bit NUMA platform.
1416 
1417           Otherwise, you should say N.
1418 
1419 config AMD_NUMA
1420         def_bool y
1421         prompt "Old style AMD Opteron NUMA detection"
1422         depends on X86_64 && NUMA && PCI
1423         ---help---
1424           Enable AMD NUMA node topology detection.  You should say Y here if
1425           you have a multi processor AMD system. This uses an old method to
1426           read the NUMA configuration directly from the builtin Northbridge
1427           of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1428           which also takes priority if both are compiled in.
1429 
1430 config X86_64_ACPI_NUMA
1431         def_bool y
1432         prompt "ACPI NUMA detection"
1433         depends on X86_64 && NUMA && ACPI && PCI
1434         select ACPI_NUMA
1435         ---help---
1436           Enable ACPI SRAT based node topology detection.
1437 
1438 # Some NUMA nodes have memory ranges that span
1439 # other nodes.  Even though a pfn is valid and
1440 # between a node's start and end pfns, it may not
1441 # reside on that node.  See memmap_init_zone()
1442 # for details.
1443 config NODES_SPAN_OTHER_NODES
1444         def_bool y
1445         depends on X86_64_ACPI_NUMA
1446 
1447 config NUMA_EMU
1448         bool "NUMA emulation"
1449         depends on NUMA
1450         ---help---
1451           Enable NUMA emulation. A flat machine will be split
1452           into virtual nodes when booted with "numa=fake=N", where N is the
1453           number of nodes. This is only useful for debugging.
1454 
1455 config NODES_SHIFT
1456         int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1457         range 1 10
1458         default "10" if MAXSMP
1459         default "6" if X86_64
1460         default "3"
1461         depends on NEED_MULTIPLE_NODES
1462         ---help---
1463           Specify the maximum number of NUMA Nodes available on the target
1464           system.  Increases memory reserved to accommodate various tables.
1465 
1466 config ARCH_HAVE_MEMORY_PRESENT
1467         def_bool y
1468         depends on X86_32 && DISCONTIGMEM
1469 
1470 config NEED_NODE_MEMMAP_SIZE
1471         def_bool y
1472         depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1473 
1474 config ARCH_FLATMEM_ENABLE
1475         def_bool y
1476         depends on X86_32 && !NUMA
1477 
1478 config ARCH_DISCONTIGMEM_ENABLE
1479         def_bool y
1480         depends on NUMA && X86_32
1481 
1482 config ARCH_DISCONTIGMEM_DEFAULT
1483         def_bool y
1484         depends on NUMA && X86_32
1485 
1486 config ARCH_SPARSEMEM_ENABLE
1487         def_bool y
1488         depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1489         select SPARSEMEM_STATIC if X86_32
1490         select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1491 
1492 config ARCH_SPARSEMEM_DEFAULT
1493         def_bool y
1494         depends on X86_64
1495 
1496 config ARCH_SELECT_MEMORY_MODEL
1497         def_bool y
1498         depends on ARCH_SPARSEMEM_ENABLE
1499 
1500 config ARCH_MEMORY_PROBE
1501         bool "Enable sysfs memory/probe interface"
1502         depends on X86_64 && MEMORY_HOTPLUG
1503         help
1504           This option enables a sysfs memory/probe interface for testing.
1505           See Documentation/memory-hotplug.txt for more information.
1506           If you are unsure how to answer this question, answer N.
1507 
1508 config ARCH_PROC_KCORE_TEXT
1509         def_bool y
1510         depends on X86_64 && PROC_KCORE
1511 
1512 config ILLEGAL_POINTER_VALUE
1513        hex
1514        default 0 if X86_32
1515        default 0xdead000000000000 if X86_64
1516 
1517 source "mm/Kconfig"
1518 
1519 config X86_PMEM_LEGACY_DEVICE
1520         bool
1521 
1522 config X86_PMEM_LEGACY
1523         tristate "Support non-standard NVDIMMs and ADR protected memory"
1524         depends on PHYS_ADDR_T_64BIT
1525         depends on BLK_DEV
1526         select X86_PMEM_LEGACY_DEVICE
1527         select LIBNVDIMM
1528         help
1529           Treat memory marked using the non-standard e820 type of 12 as used
1530           by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1531           The kernel will offer these regions to the 'pmem' driver so
1532           they can be used for persistent storage.
1533 
1534           Say Y if unsure.
1535 
1536 config HIGHPTE
1537         bool "Allocate 3rd-level pagetables from highmem"
1538         depends on HIGHMEM
1539         ---help---
1540           The VM uses one page table entry for each page of physical memory.
1541           For systems with a lot of RAM, this can be wasteful of precious
1542           low memory.  Setting this option will put user-space page table
1543           entries in high memory.
1544 
1545 config X86_CHECK_BIOS_CORRUPTION
1546         bool "Check for low memory corruption"
1547         ---help---
1548           Periodically check for memory corruption in low memory, which
1549           is suspected to be caused by BIOS.  Even when enabled in the
1550           configuration, it is disabled at runtime.  Enable it by
1551           setting "memory_corruption_check=1" on the kernel command
1552           line.  By default it scans the low 64k of memory every 60
1553           seconds; see the memory_corruption_check_size and
1554           memory_corruption_check_period parameters in
1555           Documentation/admin-guide/kernel-parameters.rst to adjust this.
1556 
1557           When enabled with the default parameters, this option has
1558           almost no overhead, as it reserves a relatively small amount
1559           of memory and scans it infrequently.  It both detects corruption
1560           and prevents it from affecting the running system.
1561 
1562           It is, however, intended as a diagnostic tool; if repeatable
1563           BIOS-originated corruption always affects the same memory,
1564           you can use memmap= to prevent the kernel from using that
1565           memory.
1566 
1567 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1568         bool "Set the default setting of memory_corruption_check"
1569         depends on X86_CHECK_BIOS_CORRUPTION
1570         default y
1571         ---help---
1572           Set whether the default state of memory_corruption_check is
1573           on or off.
1574 
1575 config X86_RESERVE_LOW
1576         int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1577         default 64
1578         range 4 640
1579         ---help---
1580           Specify the amount of low memory to reserve for the BIOS.
1581 
1582           The first page contains BIOS data structures that the kernel
1583           must not use, so that page must always be reserved.
1584 
1585           By default we reserve the first 64K of physical RAM, as a
1586           number of BIOSes are known to corrupt that memory range
1587           during events such as suspend/resume or monitor cable
1588           insertion, so it must not be used by the kernel.
1589 
1590           You can set this to 4 if you are absolutely sure that you
1591           trust the BIOS to get all its memory reservations and usages
1592           right.  If you know your BIOS have problems beyond the
1593           default 64K area, you can set this to 640 to avoid using the
1594           entire low memory range.
1595 
1596           If you have doubts about the BIOS (e.g. suspend/resume does
1597           not work or there's kernel crashes after certain hardware
1598           hotplug events) then you might want to enable
1599           X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1600           typical corruption patterns.
1601 
1602           Leave this to the default value of 64 if you are unsure.
1603 
1604 config MATH_EMULATION
1605         bool
1606         depends on MODIFY_LDT_SYSCALL
1607         prompt "Math emulation" if X86_32
1608         ---help---
1609           Linux can emulate a math coprocessor (used for floating point
1610           operations) if you don't have one. 486DX and Pentium processors have
1611           a math coprocessor built in, 486SX and 386 do not, unless you added
1612           a 487DX or 387, respectively. (The messages during boot time can
1613           give you some hints here ["man dmesg"].) Everyone needs either a
1614           coprocessor or this emulation.
1615 
1616           If you don't have a math coprocessor, you need to say Y here; if you
1617           say Y here even though you have a coprocessor, the coprocessor will
1618           be used nevertheless. (This behavior can be changed with the kernel
1619           command line option "no387", which comes handy if your coprocessor
1620           is broken. Try "man bootparam" or see the documentation of your boot
1621           loader (lilo or loadlin) about how to pass options to the kernel at
1622           boot time.) This means that it is a good idea to say Y here if you
1623           intend to use this kernel on different machines.
1624 
1625           More information about the internals of the Linux math coprocessor
1626           emulation can be found in <file:arch/x86/math-emu/README>.
1627 
1628           If you are not sure, say Y; apart from resulting in a 66 KB bigger
1629           kernel, it won't hurt.
1630 
1631 config MTRR
1632         def_bool y
1633         prompt "MTRR (Memory Type Range Register) support" if EXPERT
1634         ---help---
1635           On Intel P6 family processors (Pentium Pro, Pentium II and later)
1636           the Memory Type Range Registers (MTRRs) may be used to control
1637           processor access to memory ranges. This is most useful if you have
1638           a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1639           allows bus write transfers to be combined into a larger transfer
1640           before bursting over the PCI/AGP bus. This can increase performance
1641           of image write operations 2.5 times or more. Saying Y here creates a
1642           /proc/mtrr file which may be used to manipulate your processor's
1643           MTRRs. Typically the X server should use this.
1644 
1645           This code has a reasonably generic interface so that similar
1646           control registers on other processors can be easily supported
1647           as well:
1648 
1649           The Cyrix 6x86, 6x86MX and M II processors have Address Range
1650           Registers (ARRs) which provide a similar functionality to MTRRs. For
1651           these, the ARRs are used to emulate the MTRRs.
1652           The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1653           MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1654           write-combining. All of these processors are supported by this code
1655           and it makes sense to say Y here if you have one of them.
1656 
1657           Saying Y here also fixes a problem with buggy SMP BIOSes which only
1658           set the MTRRs for the boot CPU and not for the secondary CPUs. This
1659           can lead to all sorts of problems, so it's good to say Y here.
1660 
1661           You can safely say Y even if your machine doesn't have MTRRs, you'll
1662           just add about 9 KB to your kernel.
1663 
1664           See <file:Documentation/x86/mtrr.txt> for more information.
1665 
1666 config MTRR_SANITIZER
1667         def_bool y
1668         prompt "MTRR cleanup support"
1669         depends on MTRR
1670         ---help---
1671           Convert MTRR layout from continuous to discrete, so X drivers can
1672           add writeback entries.
1673 
1674           Can be disabled with disable_mtrr_cleanup on the kernel command line.
1675           The largest mtrr entry size for a continuous block can be set with
1676           mtrr_chunk_size.
1677 
1678           If unsure, say Y.
1679 
1680 config MTRR_SANITIZER_ENABLE_DEFAULT
1681         int "MTRR cleanup enable value (0-1)"
1682         range 0 1
1683         default "0"
1684         depends on MTRR_SANITIZER
1685         ---help---
1686           Enable mtrr cleanup default value
1687 
1688 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1689         int "MTRR cleanup spare reg num (0-7)"
1690         range 0 7
1691         default "1"
1692         depends on MTRR_SANITIZER
1693         ---help---
1694           mtrr cleanup spare entries default, it can be changed via
1695           mtrr_spare_reg_nr=N on the kernel command line.
1696 
1697 config X86_PAT
1698         def_bool y
1699         prompt "x86 PAT support" if EXPERT
1700         depends on MTRR
1701         ---help---
1702           Use PAT attributes to setup page level cache control.
1703 
1704           PATs are the modern equivalents of MTRRs and are much more
1705           flexible than MTRRs.
1706 
1707           Say N here if you see bootup problems (boot crash, boot hang,
1708           spontaneous reboots) or a non-working video driver.
1709 
1710           If unsure, say Y.
1711 
1712 config ARCH_USES_PG_UNCACHED
1713         def_bool y
1714         depends on X86_PAT
1715 
1716 config ARCH_RANDOM
1717         def_bool y
1718         prompt "x86 architectural random number generator" if EXPERT
1719         ---help---
1720           Enable the x86 architectural RDRAND instruction
1721           (Intel Bull Mountain technology) to generate random numbers.
1722           If supported, this is a high bandwidth, cryptographically
1723           secure hardware random number generator.
1724 
1725 config X86_SMAP
1726         def_bool y
1727         prompt "Supervisor Mode Access Prevention" if EXPERT
1728         ---help---
1729           Supervisor Mode Access Prevention (SMAP) is a security
1730           feature in newer Intel processors.  There is a small
1731           performance cost if this enabled and turned on; there is
1732           also a small increase in the kernel size if this is enabled.
1733 
1734           If unsure, say Y.
1735 
1736 config X86_INTEL_MPX
1737         prompt "Intel MPX (Memory Protection Extensions)"
1738         def_bool n
1739         depends on CPU_SUP_INTEL
1740         ---help---
1741           MPX provides hardware features that can be used in
1742           conjunction with compiler-instrumented code to check
1743           memory references.  It is designed to detect buffer
1744           overflow or underflow bugs.
1745 
1746           This option enables running applications which are
1747           instrumented or otherwise use MPX.  It does not use MPX
1748           itself inside the kernel or to protect the kernel
1749           against bad memory references.
1750 
1751           Enabling this option will make the kernel larger:
1752           ~8k of kernel text and 36 bytes of data on a 64-bit
1753           defconfig.  It adds a long to the 'mm_struct' which
1754           will increase the kernel memory overhead of each
1755           process and adds some branches to paths used during
1756           exec() and munmap().
1757 
1758           For details, see Documentation/x86/intel_mpx.txt
1759 
1760           If unsure, say N.
1761 
1762 config X86_INTEL_MEMORY_PROTECTION_KEYS
1763         prompt "Intel Memory Protection Keys"
1764         def_bool y
1765         # Note: only available in 64-bit mode
1766         depends on CPU_SUP_INTEL && X86_64
1767         select ARCH_USES_HIGH_VMA_FLAGS
1768         select ARCH_HAS_PKEYS
1769         ---help---
1770           Memory Protection Keys provides a mechanism for enforcing
1771           page-based protections, but without requiring modification of the
1772           page tables when an application changes protection domains.
1773 
1774           For details, see Documentation/x86/protection-keys.txt
1775 
1776           If unsure, say y.
1777 
1778 config EFI
1779         bool "EFI runtime service support"
1780         depends on ACPI
1781         select UCS2_STRING
1782         select EFI_RUNTIME_WRAPPERS
1783         ---help---
1784           This enables the kernel to use EFI runtime services that are
1785           available (such as the EFI variable services).
1786 
1787           This option is only useful on systems that have EFI firmware.
1788           In addition, you should use the latest ELILO loader available
1789           at <http://elilo.sourceforge.net> in order to take advantage
1790           of EFI runtime services. However, even with this option, the
1791           resultant kernel should continue to boot on existing non-EFI
1792           platforms.
1793 
1794 config EFI_STUB
1795        bool "EFI stub support"
1796        depends on EFI && !X86_USE_3DNOW
1797        select RELOCATABLE
1798        ---help---
1799           This kernel feature allows a bzImage to be loaded directly
1800           by EFI firmware without the use of a bootloader.
1801 
1802           See Documentation/efi-stub.txt for more information.
1803 
1804 config EFI_MIXED
1805         bool "EFI mixed-mode support"
1806         depends on EFI_STUB && X86_64
1807         ---help---
1808            Enabling this feature allows a 64-bit kernel to be booted
1809            on a 32-bit firmware, provided that your CPU supports 64-bit
1810            mode.
1811 
1812            Note that it is not possible to boot a mixed-mode enabled
1813            kernel via the EFI boot stub - a bootloader that supports
1814            the EFI handover protocol must be used.
1815 
1816            If unsure, say N.
1817 
1818 config SECCOMP
1819         def_bool y
1820         prompt "Enable seccomp to safely compute untrusted bytecode"
1821         ---help---
1822           This kernel feature is useful for number crunching applications
1823           that may need to compute untrusted bytecode during their
1824           execution. By using pipes or other transports made available to
1825           the process as file descriptors supporting the read/write
1826           syscalls, it's possible to isolate those applications in
1827           their own address space using seccomp. Once seccomp is
1828           enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1829           and the task is only allowed to execute a few safe syscalls
1830           defined by each seccomp mode.
1831 
1832           If unsure, say Y. Only embedded should say N here.
1833 
1834 source kernel/Kconfig.hz
1835 
1836 config KEXEC
1837         bool "kexec system call"
1838         select KEXEC_CORE
1839         ---help---
1840           kexec is a system call that implements the ability to shutdown your
1841           current kernel, and to start another kernel.  It is like a reboot
1842           but it is independent of the system firmware.   And like a reboot
1843           you can start any kernel with it, not just Linux.
1844 
1845           The name comes from the similarity to the exec system call.
1846 
1847           It is an ongoing process to be certain the hardware in a machine
1848           is properly shutdown, so do not be surprised if this code does not
1849           initially work for you.  As of this writing the exact hardware
1850           interface is strongly in flux, so no good recommendation can be
1851           made.
1852 
1853 config KEXEC_FILE
1854         bool "kexec file based system call"
1855         select KEXEC_CORE
1856         select BUILD_BIN2C
1857         depends on X86_64
1858         depends on CRYPTO=y
1859         depends on CRYPTO_SHA256=y
1860         ---help---
1861           This is new version of kexec system call. This system call is
1862           file based and takes file descriptors as system call argument
1863           for kernel and initramfs as opposed to list of segments as
1864           accepted by previous system call.
1865 
1866 config KEXEC_VERIFY_SIG
1867         bool "Verify kernel signature during kexec_file_load() syscall"
1868         depends on KEXEC_FILE
1869         ---help---
1870           This option makes kernel signature verification mandatory for
1871           the kexec_file_load() syscall.
1872 
1873           In addition to that option, you need to enable signature
1874           verification for the corresponding kernel image type being
1875           loaded in order for this to work.
1876 
1877 config KEXEC_BZIMAGE_VERIFY_SIG
1878         bool "Enable bzImage signature verification support"
1879         depends on KEXEC_VERIFY_SIG
1880         depends on SIGNED_PE_FILE_VERIFICATION
1881         select SYSTEM_TRUSTED_KEYRING
1882         ---help---
1883           Enable bzImage signature verification support.
1884 
1885 config CRASH_DUMP
1886         bool "kernel crash dumps"
1887         depends on X86_64 || (X86_32 && HIGHMEM)
1888         ---help---
1889           Generate crash dump after being started by kexec.
1890           This should be normally only set in special crash dump kernels
1891           which are loaded in the main kernel with kexec-tools into
1892           a specially reserved region and then later executed after
1893           a crash by kdump/kexec. The crash dump kernel must be compiled
1894           to a memory address not used by the main kernel or BIOS using
1895           PHYSICAL_START, or it must be built as a relocatable image
1896           (CONFIG_RELOCATABLE=y).
1897           For more details see Documentation/kdump/kdump.txt
1898 
1899 config KEXEC_JUMP
1900         bool "kexec jump"
1901         depends on KEXEC && HIBERNATION
1902         ---help---
1903           Jump between original kernel and kexeced kernel and invoke
1904           code in physical address mode via KEXEC
1905 
1906 config PHYSICAL_START
1907         hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1908         default "0x1000000"
1909         ---help---
1910           This gives the physical address where the kernel is loaded.
1911 
1912           If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1913           bzImage will decompress itself to above physical address and
1914           run from there. Otherwise, bzImage will run from the address where
1915           it has been loaded by the boot loader and will ignore above physical
1916           address.
1917 
1918           In normal kdump cases one does not have to set/change this option
1919           as now bzImage can be compiled as a completely relocatable image
1920           (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1921           address. This option is mainly useful for the folks who don't want
1922           to use a bzImage for capturing the crash dump and want to use a
1923           vmlinux instead. vmlinux is not relocatable hence a kernel needs
1924           to be specifically compiled to run from a specific memory area
1925           (normally a reserved region) and this option comes handy.
1926 
1927           So if you are using bzImage for capturing the crash dump,
1928           leave the value here unchanged to 0x1000000 and set
1929           CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
1930           for capturing the crash dump change this value to start of
1931           the reserved region.  In other words, it can be set based on
1932           the "X" value as specified in the "crashkernel=YM@XM"
1933           command line boot parameter passed to the panic-ed
1934           kernel. Please take a look at Documentation/kdump/kdump.txt
1935           for more details about crash dumps.
1936 
1937           Usage of bzImage for capturing the crash dump is recommended as
1938           one does not have to build two kernels. Same kernel can be used
1939           as production kernel and capture kernel. Above option should have
1940           gone away after relocatable bzImage support is introduced. But it
1941           is present because there are users out there who continue to use
1942           vmlinux for dump capture. This option should go away down the
1943           line.
1944 
1945           Don't change this unless you know what you are doing.
1946 
1947 config RELOCATABLE
1948         bool "Build a relocatable kernel"
1949         default y
1950         ---help---
1951           This builds a kernel image that retains relocation information
1952           so it can be loaded someplace besides the default 1MB.
1953           The relocations tend to make the kernel binary about 10% larger,
1954           but are discarded at runtime.
1955 
1956           One use is for the kexec on panic case where the recovery kernel
1957           must live at a different physical address than the primary
1958           kernel.
1959 
1960           Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1961           it has been loaded at and the compile time physical address
1962           (CONFIG_PHYSICAL_START) is used as the minimum location.
1963 
1964 config RANDOMIZE_BASE
1965         bool "Randomize the address of the kernel image (KASLR)"
1966         depends on RELOCATABLE
1967         default n
1968         ---help---
1969           In support of Kernel Address Space Layout Randomization (KASLR),
1970           this randomizes the physical address at which the kernel image
1971           is decompressed and the virtual address where the kernel
1972           image is mapped, as a security feature that deters exploit
1973           attempts relying on knowledge of the location of kernel
1974           code internals.
1975 
1976           On 64-bit, the kernel physical and virtual addresses are
1977           randomized separately. The physical address will be anywhere
1978           between 16MB and the top of physical memory (up to 64TB). The
1979           virtual address will be randomized from 16MB up to 1GB (9 bits
1980           of entropy). Note that this also reduces the memory space
1981           available to kernel modules from 1.5GB to 1GB.
1982 
1983           On 32-bit, the kernel physical and virtual addresses are
1984           randomized together. They will be randomized from 16MB up to
1985           512MB (8 bits of entropy).
1986 
1987           Entropy is generated using the RDRAND instruction if it is
1988           supported. If RDTSC is supported, its value is mixed into
1989           the entropy pool as well. If neither RDRAND nor RDTSC are
1990           supported, then entropy is read from the i8254 timer. The
1991           usable entropy is limited by the kernel being built using
1992           2GB addressing, and that PHYSICAL_ALIGN must be at a
1993           minimum of 2MB. As a result, only 10 bits of entropy are
1994           theoretically possible, but the implementations are further
1995           limited due to memory layouts.
1996 
1997           If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot
1998           time. To enable it, boot with "kaslr" on the kernel command
1999           line (which will also disable hibernation).
2000 
2001           If unsure, say N.
2002 
2003 # Relocation on x86 needs some additional build support
2004 config X86_NEED_RELOCS
2005         def_bool y
2006         depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2007 
2008 config PHYSICAL_ALIGN
2009         hex "Alignment value to which kernel should be aligned"
2010         default "0x200000"
2011         range 0x2000 0x1000000 if X86_32
2012         range 0x200000 0x1000000 if X86_64
2013         ---help---
2014           This value puts the alignment restrictions on physical address
2015           where kernel is loaded and run from. Kernel is compiled for an
2016           address which meets above alignment restriction.
2017 
2018           If bootloader loads the kernel at a non-aligned address and
2019           CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2020           address aligned to above value and run from there.
2021 
2022           If bootloader loads the kernel at a non-aligned address and
2023           CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2024           load address and decompress itself to the address it has been
2025           compiled for and run from there. The address for which kernel is
2026           compiled already meets above alignment restrictions. Hence the
2027           end result is that kernel runs from a physical address meeting
2028           above alignment restrictions.
2029 
2030           On 32-bit this value must be a multiple of 0x2000. On 64-bit
2031           this value must be a multiple of 0x200000.
2032 
2033           Don't change this unless you know what you are doing.
2034 
2035 config RANDOMIZE_MEMORY
2036         bool "Randomize the kernel memory sections"
2037         depends on X86_64
2038         depends on RANDOMIZE_BASE
2039         default RANDOMIZE_BASE
2040         ---help---
2041            Randomizes the base virtual address of kernel memory sections
2042            (physical memory mapping, vmalloc & vmemmap). This security feature
2043            makes exploits relying on predictable memory locations less reliable.
2044 
2045            The order of allocations remains unchanged. Entropy is generated in
2046            the same way as RANDOMIZE_BASE. Current implementation in the optimal
2047            configuration have in average 30,000 different possible virtual
2048            addresses for each memory section.
2049 
2050            If unsure, say N.
2051 
2052 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2053         hex "Physical memory mapping padding" if EXPERT
2054         depends on RANDOMIZE_MEMORY
2055         default "0xa" if MEMORY_HOTPLUG
2056         default "0x0"
2057         range 0x1 0x40 if MEMORY_HOTPLUG
2058         range 0x0 0x40
2059         ---help---
2060            Define the padding in terabytes added to the existing physical
2061            memory size during kernel memory randomization. It is useful
2062            for memory hotplug support but reduces the entropy available for
2063            address randomization.
2064 
2065            If unsure, leave at the default value.
2066 
2067 config HOTPLUG_CPU
2068         bool "Support for hot-pluggable CPUs"
2069         depends on SMP
2070         ---help---
2071           Say Y here to allow turning CPUs off and on. CPUs can be
2072           controlled through /sys/devices/system/cpu.
2073           ( Note: power management support will enable this option
2074             automatically on SMP systems. )
2075           Say N if you want to disable CPU hotplug.
2076 
2077 config BOOTPARAM_HOTPLUG_CPU0
2078         bool "Set default setting of cpu0_hotpluggable"
2079         default n
2080         depends on HOTPLUG_CPU
2081         ---help---
2082           Set whether default state of cpu0_hotpluggable is on or off.
2083 
2084           Say Y here to enable CPU0 hotplug by default. If this switch
2085           is turned on, there is no need to give cpu0_hotplug kernel
2086           parameter and the CPU0 hotplug feature is enabled by default.
2087 
2088           Please note: there are two known CPU0 dependencies if you want
2089           to enable the CPU0 hotplug feature either by this switch or by
2090           cpu0_hotplug kernel parameter.
2091 
2092           First, resume from hibernate or suspend always starts from CPU0.
2093           So hibernate and suspend are prevented if CPU0 is offline.
2094 
2095           Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2096           offline if any interrupt can not migrate out of CPU0. There may
2097           be other CPU0 dependencies.
2098 
2099           Please make sure the dependencies are under your control before
2100           you enable this feature.
2101 
2102           Say N if you don't want to enable CPU0 hotplug feature by default.
2103           You still can enable the CPU0 hotplug feature at boot by kernel
2104           parameter cpu0_hotplug.
2105 
2106 config DEBUG_HOTPLUG_CPU0
2107         def_bool n
2108         prompt "Debug CPU0 hotplug"
2109         depends on HOTPLUG_CPU
2110         ---help---
2111           Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2112           soon as possible and boots up userspace with CPU0 offlined. User
2113           can online CPU0 back after boot time.
2114 
2115           To debug CPU0 hotplug, you need to enable CPU0 offline/online
2116           feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2117           compilation or giving cpu0_hotplug kernel parameter at boot.
2118 
2119           If unsure, say N.
2120 
2121 config COMPAT_VDSO
2122         def_bool n
2123         prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2124         depends on COMPAT_32
2125         ---help---
2126           Certain buggy versions of glibc will crash if they are
2127           presented with a 32-bit vDSO that is not mapped at the address
2128           indicated in its segment table.
2129 
2130           The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2131           and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2132           49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2133           the only released version with the bug, but OpenSUSE 9
2134           contains a buggy "glibc 2.3.2".
2135 
2136           The symptom of the bug is that everything crashes on startup, saying:
2137           dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2138 
2139           Saying Y here changes the default value of the vdso32 boot
2140           option from 1 to 0, which turns off the 32-bit vDSO entirely.
2141           This works around the glibc bug but hurts performance.
2142 
2143           If unsure, say N: if you are compiling your own kernel, you
2144           are unlikely to be using a buggy version of glibc.
2145 
2146 choice
2147         prompt "vsyscall table for legacy applications"
2148         depends on X86_64
2149         default LEGACY_VSYSCALL_EMULATE
2150         help
2151           Legacy user code that does not know how to find the vDSO expects
2152           to be able to issue three syscalls by calling fixed addresses in
2153           kernel space. Since this location is not randomized with ASLR,
2154           it can be used to assist security vulnerability exploitation.
2155 
2156           This setting can be changed at boot time via the kernel command
2157           line parameter vsyscall=[native|emulate|none].
2158 
2159           On a system with recent enough glibc (2.14 or newer) and no
2160           static binaries, you can say None without a performance penalty
2161           to improve security.
2162 
2163           If unsure, select "Emulate".
2164 
2165         config LEGACY_VSYSCALL_NATIVE
2166                 bool "Native"
2167                 help
2168                   Actual executable code is located in the fixed vsyscall
2169                   address mapping, implementing time() efficiently. Since
2170                   this makes the mapping executable, it can be used during
2171                   security vulnerability exploitation (traditionally as
2172                   ROP gadgets). This configuration is not recommended.
2173 
2174         config LEGACY_VSYSCALL_EMULATE
2175                 bool "Emulate"
2176                 help
2177                   The kernel traps and emulates calls into the fixed
2178                   vsyscall address mapping. This makes the mapping
2179                   non-executable, but it still contains known contents,
2180                   which could be used in certain rare security vulnerability
2181                   exploits. This configuration is recommended when userspace
2182                   still uses the vsyscall area.
2183 
2184         config LEGACY_VSYSCALL_NONE
2185                 bool "None"
2186                 help
2187                   There will be no vsyscall mapping at all. This will
2188                   eliminate any risk of ASLR bypass due to the vsyscall
2189                   fixed address mapping. Attempts to use the vsyscalls
2190                   will be reported to dmesg, so that either old or
2191                   malicious userspace programs can be identified.
2192 
2193 endchoice
2194 
2195 config CMDLINE_BOOL
2196         bool "Built-in kernel command line"
2197         ---help---
2198           Allow for specifying boot arguments to the kernel at
2199           build time.  On some systems (e.g. embedded ones), it is
2200           necessary or convenient to provide some or all of the
2201           kernel boot arguments with the kernel itself (that is,
2202           to not rely on the boot loader to provide them.)
2203 
2204           To compile command line arguments into the kernel,
2205           set this option to 'Y', then fill in the
2206           boot arguments in CONFIG_CMDLINE.
2207 
2208           Systems with fully functional boot loaders (i.e. non-embedded)
2209           should leave this option set to 'N'.
2210 
2211 config CMDLINE
2212         string "Built-in kernel command string"
2213         depends on CMDLINE_BOOL
2214         default ""
2215         ---help---
2216           Enter arguments here that should be compiled into the kernel
2217           image and used at boot time.  If the boot loader provides a
2218           command line at boot time, it is appended to this string to
2219           form the full kernel command line, when the system boots.
2220 
2221           However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2222           change this behavior.
2223 
2224           In most cases, the command line (whether built-in or provided
2225           by the boot loader) should specify the device for the root
2226           file system.
2227 
2228 config CMDLINE_OVERRIDE
2229         bool "Built-in command line overrides boot loader arguments"
2230         depends on CMDLINE_BOOL
2231         ---help---
2232           Set this option to 'Y' to have the kernel ignore the boot loader
2233           command line, and use ONLY the built-in command line.
2234 
2235           This is used to work around broken boot loaders.  This should
2236           be set to 'N' under normal conditions.
2237 
2238 config MODIFY_LDT_SYSCALL
2239         bool "Enable the LDT (local descriptor table)" if EXPERT
2240         default y
2241         ---help---
2242           Linux can allow user programs to install a per-process x86
2243           Local Descriptor Table (LDT) using the modify_ldt(2) system
2244           call.  This is required to run 16-bit or segmented code such as
2245           DOSEMU or some Wine programs.  It is also used by some very old
2246           threading libraries.
2247 
2248           Enabling this feature adds a small amount of overhead to
2249           context switches and increases the low-level kernel attack
2250           surface.  Disabling it removes the modify_ldt(2) system call.
2251 
2252           Saying 'N' here may make sense for embedded or server kernels.
2253 
2254 source "kernel/livepatch/Kconfig"
2255 
2256 endmenu
2257 
2258 config ARCH_ENABLE_MEMORY_HOTPLUG
2259         def_bool y
2260         depends on X86_64 || (X86_32 && HIGHMEM)
2261 
2262 config ARCH_ENABLE_MEMORY_HOTREMOVE
2263         def_bool y
2264         depends on MEMORY_HOTPLUG
2265 
2266 config USE_PERCPU_NUMA_NODE_ID
2267         def_bool y
2268         depends on NUMA
2269 
2270 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2271         def_bool y
2272         depends on X86_64 || X86_PAE
2273 
2274 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2275         def_bool y
2276         depends on X86_64 && HUGETLB_PAGE && MIGRATION
2277 
2278 menu "Power management and ACPI options"
2279 
2280 config ARCH_HIBERNATION_HEADER
2281         def_bool y
2282         depends on X86_64 && HIBERNATION
2283 
2284 source "kernel/power/Kconfig"
2285 
2286 source "drivers/acpi/Kconfig"
2287 
2288 source "drivers/sfi/Kconfig"
2289 
2290 config X86_APM_BOOT
2291         def_bool y
2292         depends on APM
2293 
2294 menuconfig APM
2295         tristate "APM (Advanced Power Management) BIOS support"
2296         depends on X86_32 && PM_SLEEP
2297         ---help---
2298           APM is a BIOS specification for saving power using several different
2299           techniques. This is mostly useful for battery powered laptops with
2300           APM compliant BIOSes. If you say Y here, the system time will be
2301           reset after a RESUME operation, the /proc/apm device will provide
2302           battery status information, and user-space programs will receive
2303           notification of APM "events" (e.g. battery status change).
2304 
2305           If you select "Y" here, you can disable actual use of the APM
2306           BIOS by passing the "apm=off" option to the kernel at boot time.
2307 
2308           Note that the APM support is almost completely disabled for
2309           machines with more than one CPU.
2310 
2311           In order to use APM, you will need supporting software. For location
2312           and more information, read <file:Documentation/power/apm-acpi.txt>
2313           and the Battery Powered Linux mini-HOWTO, available from
2314           <http://www.tldp.org/docs.html#howto>.
2315 
2316           This driver does not spin down disk drives (see the hdparm(8)
2317           manpage ("man 8 hdparm") for that), and it doesn't turn off
2318           VESA-compliant "green" monitors.
2319 
2320           This driver does not support the TI 4000M TravelMate and the ACER
2321           486/DX4/75 because they don't have compliant BIOSes. Many "green"
2322           desktop machines also don't have compliant BIOSes, and this driver
2323           may cause those machines to panic during the boot phase.
2324 
2325           Generally, if you don't have a battery in your machine, there isn't
2326           much point in using this driver and you should say N. If you get
2327           random kernel OOPSes or reboots that don't seem to be related to
2328           anything, try disabling/enabling this option (or disabling/enabling
2329           APM in your BIOS).
2330 
2331           Some other things you should try when experiencing seemingly random,
2332           "weird" problems:
2333 
2334           1) make sure that you have enough swap space and that it is
2335           enabled.
2336           2) pass the "no-hlt" option to the kernel
2337           3) switch on floating point emulation in the kernel and pass
2338           the "no387" option to the kernel
2339           4) pass the "floppy=nodma" option to the kernel
2340           5) pass the "mem=4M" option to the kernel (thereby disabling
2341           all but the first 4 MB of RAM)
2342           6) make sure that the CPU is not over clocked.
2343           7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2344           8) disable the cache from your BIOS settings
2345           9) install a fan for the video card or exchange video RAM
2346           10) install a better fan for the CPU
2347           11) exchange RAM chips
2348           12) exchange the motherboard.
2349 
2350           To compile this driver as a module, choose M here: the
2351           module will be called apm.
2352 
2353 if APM
2354 
2355 config APM_IGNORE_USER_SUSPEND
2356         bool "Ignore USER SUSPEND"
2357         ---help---
2358           This option will ignore USER SUSPEND requests. On machines with a
2359           compliant APM BIOS, you want to say N. However, on the NEC Versa M
2360           series notebooks, it is necessary to say Y because of a BIOS bug.
2361 
2362 config APM_DO_ENABLE
2363         bool "Enable PM at boot time"
2364         ---help---
2365           Enable APM features at boot time. From page 36 of the APM BIOS
2366           specification: "When disabled, the APM BIOS does not automatically
2367           power manage devices, enter the Standby State, enter the Suspend
2368           State, or take power saving steps in response to CPU Idle calls."
2369           This driver will make CPU Idle calls when Linux is idle (unless this
2370           feature is turned off -- see "Do CPU IDLE calls", below). This
2371           should always save battery power, but more complicated APM features
2372           will be dependent on your BIOS implementation. You may need to turn
2373           this option off if your computer hangs at boot time when using APM
2374           support, or if it beeps continuously instead of suspending. Turn
2375           this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2376           T400CDT. This is off by default since most machines do fine without
2377           this feature.
2378 
2379 config APM_CPU_IDLE
2380         depends on CPU_IDLE
2381         bool "Make CPU Idle calls when idle"
2382         ---help---
2383           Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2384           On some machines, this can activate improved power savings, such as
2385           a slowed CPU clock rate, when the machine is idle. These idle calls
2386           are made after the idle loop has run for some length of time (e.g.,
2387           333 mS). On some machines, this will cause a hang at boot time or
2388           whenever the CPU becomes idle. (On machines with more than one CPU,
2389           this option does nothing.)
2390 
2391 config APM_DISPLAY_BLANK
2392         bool "Enable console blanking using APM"
2393         ---help---
2394           Enable console blanking using the APM. Some laptops can use this to
2395           turn off the LCD backlight when the screen blanker of the Linux
2396           virtual console blanks the screen. Note that this is only used by
2397           the virtual console screen blanker, and won't turn off the backlight
2398           when using the X Window system. This also doesn't have anything to
2399           do with your VESA-compliant power-saving monitor. Further, this
2400           option doesn't work for all laptops -- it might not turn off your
2401           backlight at all, or it might print a lot of errors to the console,
2402           especially if you are using gpm.
2403 
2404 config APM_ALLOW_INTS
2405         bool "Allow interrupts during APM BIOS calls"
2406         ---help---
2407           Normally we disable external interrupts while we are making calls to
2408           the APM BIOS as a measure to lessen the effects of a badly behaving
2409           BIOS implementation.  The BIOS should reenable interrupts if it
2410           needs to.  Unfortunately, some BIOSes do not -- especially those in
2411           many of the newer IBM Thinkpads.  If you experience hangs when you
2412           suspend, try setting this to Y.  Otherwise, say N.
2413 
2414 endif # APM
2415 
2416 source "drivers/cpufreq/Kconfig"
2417 
2418 source "drivers/cpuidle/Kconfig"
2419 
2420 source "drivers/idle/Kconfig"
2421 
2422 endmenu
2423 
2424 
2425 menu "Bus options (PCI etc.)"
2426 
2427 config PCI
2428         bool "PCI support"
2429         default y
2430         ---help---
2431           Find out whether you have a PCI motherboard. PCI is the name of a
2432           bus system, i.e. the way the CPU talks to the other stuff inside
2433           your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2434           VESA. If you have PCI, say Y, otherwise N.
2435 
2436 choice
2437         prompt "PCI access mode"
2438         depends on X86_32 && PCI
2439         default PCI_GOANY
2440         ---help---
2441           On PCI systems, the BIOS can be used to detect the PCI devices and
2442           determine their configuration. However, some old PCI motherboards
2443           have BIOS bugs and may crash if this is done. Also, some embedded
2444           PCI-based systems don't have any BIOS at all. Linux can also try to
2445           detect the PCI hardware directly without using the BIOS.
2446 
2447           With this option, you can specify how Linux should detect the
2448           PCI devices. If you choose "BIOS", the BIOS will be used,
2449           if you choose "Direct", the BIOS won't be used, and if you
2450           choose "MMConfig", then PCI Express MMCONFIG will be used.
2451           If you choose "Any", the kernel will try MMCONFIG, then the
2452           direct access method and falls back to the BIOS if that doesn't
2453           work. If unsure, go with the default, which is "Any".
2454 
2455 config PCI_GOBIOS
2456         bool "BIOS"
2457 
2458 config PCI_GOMMCONFIG
2459         bool "MMConfig"
2460 
2461 config PCI_GODIRECT
2462         bool "Direct"
2463 
2464 config PCI_GOOLPC
2465         bool "OLPC XO-1"
2466         depends on OLPC
2467 
2468 config PCI_GOANY
2469         bool "Any"
2470 
2471 endchoice
2472 
2473 config PCI_BIOS
2474         def_bool y
2475         depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2476 
2477 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2478 config PCI_DIRECT
2479         def_bool y
2480         depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2481 
2482 config PCI_MMCONFIG
2483         def_bool y
2484         depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2485 
2486 config PCI_OLPC
2487         def_bool y
2488         depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2489 
2490 config PCI_XEN
2491         def_bool y
2492         depends on PCI && XEN
2493         select SWIOTLB_XEN
2494 
2495 config PCI_DOMAINS
2496         def_bool y
2497         depends on PCI
2498 
2499 config PCI_MMCONFIG
2500         bool "Support mmconfig PCI config space access"
2501         depends on X86_64 && PCI && ACPI
2502 
2503 config PCI_CNB20LE_QUIRK
2504         bool "Read CNB20LE Host Bridge Windows" if EXPERT
2505         depends on PCI
2506         help
2507           Read the PCI windows out of the CNB20LE host bridge. This allows
2508           PCI hotplug to work on systems with the CNB20LE chipset which do
2509           not have ACPI.
2510 
2511           There's no public spec for this chipset, and this functionality
2512           is known to be incomplete.
2513 
2514           You should say N unless you know you need this.
2515 
2516 source "drivers/pci/Kconfig"
2517 
2518 config ISA_BUS
2519         bool "ISA-style bus support on modern systems" if EXPERT
2520         select ISA_BUS_API
2521         help
2522           Enables ISA-style drivers on modern systems. This is necessary to
2523           support PC/104 devices on X86_64 platforms.
2524 
2525           If unsure, say N.
2526 
2527 # x86_64 have no ISA slots, but can have ISA-style DMA.
2528 config ISA_DMA_API
2529         bool "ISA-style DMA support" if (X86_64 && EXPERT)
2530         default y
2531         help
2532           Enables ISA-style DMA support for devices requiring such controllers.
2533           If unsure, say Y.
2534 
2535 if X86_32
2536 
2537 config ISA
2538         bool "ISA support"
2539         ---help---
2540           Find out whether you have ISA slots on your motherboard.  ISA is the
2541           name of a bus system, i.e. the way the CPU talks to the other stuff
2542           inside your box.  Other bus systems are PCI, EISA, MicroChannel
2543           (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2544           newer boards don't support it.  If you have ISA, say Y, otherwise N.
2545 
2546 config EISA
2547         bool "EISA support"
2548         depends on ISA
2549         ---help---
2550           The Extended Industry Standard Architecture (EISA) bus was
2551           developed as an open alternative to the IBM MicroChannel bus.
2552 
2553           The EISA bus provided some of the features of the IBM MicroChannel
2554           bus while maintaining backward compatibility with cards made for
2555           the older ISA bus.  The EISA bus saw limited use between 1988 and
2556           1995 when it was made obsolete by the PCI bus.
2557 
2558           Say Y here if you are building a kernel for an EISA-based machine.
2559 
2560           Otherwise, say N.
2561 
2562 source "drivers/eisa/Kconfig"
2563 
2564 config SCx200
2565         tristate "NatSemi SCx200 support"
2566         ---help---
2567           This provides basic support for National Semiconductor's
2568           (now AMD's) Geode processors.  The driver probes for the
2569           PCI-IDs of several on-chip devices, so its a good dependency
2570           for other scx200_* drivers.
2571 
2572           If compiled as a module, the driver is named scx200.
2573 
2574 config SCx200HR_TIMER
2575         tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2576         depends on SCx200
2577         default y
2578         ---help---
2579           This driver provides a clocksource built upon the on-chip
2580           27MHz high-resolution timer.  Its also a workaround for
2581           NSC Geode SC-1100's buggy TSC, which loses time when the
2582           processor goes idle (as is done by the scheduler).  The
2583           other workaround is idle=poll boot option.
2584 
2585 config OLPC
2586         bool "One Laptop Per Child support"
2587         depends on !X86_PAE
2588         select GPIOLIB
2589         select OF
2590         select OF_PROMTREE
2591         select IRQ_DOMAIN
2592         ---help---
2593           Add support for detecting the unique features of the OLPC
2594           XO hardware.
2595 
2596 config OLPC_XO1_PM
2597         bool "OLPC XO-1 Power Management"
2598         depends on OLPC && MFD_CS5535 && PM_SLEEP
2599         select MFD_CORE
2600         ---help---
2601           Add support for poweroff and suspend of the OLPC XO-1 laptop.
2602 
2603 config OLPC_XO1_RTC
2604         bool "OLPC XO-1 Real Time Clock"
2605         depends on OLPC_XO1_PM && RTC_DRV_CMOS
2606         ---help---
2607           Add support for the XO-1 real time clock, which can be used as a
2608           programmable wakeup source.
2609 
2610 config OLPC_XO1_SCI
2611         bool "OLPC XO-1 SCI extras"
2612         depends on OLPC && OLPC_XO1_PM
2613         depends on INPUT=y
2614         select POWER_SUPPLY
2615         select GPIO_CS5535
2616         select MFD_CORE
2617         ---help---
2618           Add support for SCI-based features of the OLPC XO-1 laptop:
2619            - EC-driven system wakeups
2620            - Power button
2621            - Ebook switch
2622            - Lid switch
2623            - AC adapter status updates
2624            - Battery status updates
2625 
2626 config OLPC_XO15_SCI
2627         bool "OLPC XO-1.5 SCI extras"
2628         depends on OLPC && ACPI
2629         select POWER_SUPPLY
2630         ---help---
2631           Add support for SCI-based features of the OLPC XO-1.5 laptop:
2632            - EC-driven system wakeups
2633            - AC adapter status updates
2634            - Battery status updates
2635 
2636 config ALIX
2637         bool "PCEngines ALIX System Support (LED setup)"
2638         select GPIOLIB
2639         ---help---
2640           This option enables system support for the PCEngines ALIX.
2641           At present this just sets up LEDs for GPIO control on
2642           ALIX2/3/6 boards.  However, other system specific setup should
2643           get added here.
2644 
2645           Note: You must still enable the drivers for GPIO and LED support
2646           (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2647 
2648           Note: You have to set alix.force=1 for boards with Award BIOS.
2649 
2650 config NET5501
2651         bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2652         select GPIOLIB
2653         ---help---
2654           This option enables system support for the Soekris Engineering net5501.
2655 
2656 config GEOS
2657         bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2658         select GPIOLIB
2659         depends on DMI
2660         ---help---
2661           This option enables system support for the Traverse Technologies GEOS.
2662 
2663 config TS5500
2664         bool "Technologic Systems TS-5500 platform support"
2665         depends on MELAN
2666         select CHECK_SIGNATURE
2667         select NEW_LEDS
2668         select LEDS_CLASS
2669         ---help---
2670           This option enables system support for the Technologic Systems TS-5500.
2671 
2672 endif # X86_32
2673 
2674 config AMD_NB
2675         def_bool y
2676         depends on CPU_SUP_AMD && PCI
2677 
2678 source "drivers/pcmcia/Kconfig"
2679 
2680 config RAPIDIO
2681         tristate "RapidIO support"
2682         depends on PCI
2683         default n
2684         help
2685           If enabled this option will include drivers and the core
2686           infrastructure code to support RapidIO interconnect devices.
2687 
2688 source "drivers/rapidio/Kconfig"
2689 
2690 config X86_SYSFB
2691         bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2692         help
2693           Firmwares often provide initial graphics framebuffers so the BIOS,
2694           bootloader or kernel can show basic video-output during boot for
2695           user-guidance and debugging. Historically, x86 used the VESA BIOS
2696           Extensions and EFI-framebuffers for this, which are mostly limited
2697           to x86.
2698           This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2699           framebuffers so the new generic system-framebuffer drivers can be
2700           used on x86. If the framebuffer is not compatible with the generic
2701           modes, it is adverticed as fallback platform framebuffer so legacy
2702           drivers like efifb, vesafb and uvesafb can pick it up.
2703           If this option is not selected, all system framebuffers are always
2704           marked as fallback platform framebuffers as usual.
2705 
2706           Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2707           not be able to pick up generic system framebuffers if this option
2708           is selected. You are highly encouraged to enable simplefb as
2709           replacement if you select this option. simplefb can correctly deal
2710           with generic system framebuffers. But you should still keep vesafb
2711           and others enabled as fallback if a system framebuffer is
2712           incompatible with simplefb.
2713 
2714           If unsure, say Y.
2715 
2716 endmenu
2717 
2718 
2719 menu "Executable file formats / Emulations"
2720 
2721 source "fs/Kconfig.binfmt"
2722 
2723 config IA32_EMULATION
2724         bool "IA32 Emulation"
2725         depends on X86_64
2726         select ARCH_WANT_OLD_COMPAT_IPC
2727         select BINFMT_ELF
2728         select COMPAT_BINFMT_ELF
2729         select COMPAT_OLD_SIGACTION
2730         ---help---
2731           Include code to run legacy 32-bit programs under a
2732           64-bit kernel. You should likely turn this on, unless you're
2733           100% sure that you don't have any 32-bit programs left.
2734 
2735 config IA32_AOUT
2736         tristate "IA32 a.out support"
2737         depends on IA32_EMULATION
2738         ---help---
2739           Support old a.out binaries in the 32bit emulation.
2740 
2741 config X86_X32
2742         bool "x32 ABI for 64-bit mode"
2743         depends on X86_64
2744         ---help---
2745           Include code to run binaries for the x32 native 32-bit ABI
2746           for 64-bit processors.  An x32 process gets access to the
2747           full 64-bit register file and wide data path while leaving
2748           pointers at 32 bits for smaller memory footprint.
2749 
2750           You will need a recent binutils (2.22 or later) with
2751           elf32_x86_64 support enabled to compile a kernel with this
2752           option set.
2753 
2754 config COMPAT_32
2755         def_bool y
2756         depends on IA32_EMULATION || X86_32
2757         select HAVE_UID16
2758         select OLD_SIGSUSPEND3
2759 
2760 config COMPAT
2761         def_bool y
2762         depends on IA32_EMULATION || X86_X32
2763 
2764 if COMPAT
2765 config COMPAT_FOR_U64_ALIGNMENT
2766         def_bool y
2767 
2768 config SYSVIPC_COMPAT
2769         def_bool y
2770         depends on SYSVIPC
2771 
2772 config KEYS_COMPAT
2773         def_bool y
2774         depends on KEYS
2775 endif
2776 
2777 endmenu
2778 
2779 
2780 config HAVE_ATOMIC_IOMAP
2781         def_bool y
2782         depends on X86_32
2783 
2784 config X86_DEV_DMA_OPS
2785         bool
2786         depends on X86_64 || STA2X11
2787 
2788 config X86_DMA_REMAP
2789         bool
2790         depends on STA2X11
2791 
2792 config PMC_ATOM
2793         def_bool y
2794         depends on PCI
2795 
2796 source "net/Kconfig"
2797 
2798 source "drivers/Kconfig"
2799 
2800 source "drivers/firmware/Kconfig"
2801 
2802 source "fs/Kconfig"
2803 
2804 source "arch/x86/Kconfig.debug"
2805 
2806 source "security/Kconfig"
2807 
2808 source "crypto/Kconfig"
2809 
2810 source "arch/x86/kvm/Kconfig"
2811 
2812 source "lib/Kconfig"

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