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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 
 13 config X86_64
 14         def_bool y
 15         depends on 64BIT
 16 
 17 ### Arch settings
 18 config X86
 19         def_bool y
 20         select ACPI_LEGACY_TABLES_LOOKUP        if ACPI
 21         select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
 22         select ANON_INODES
 23         select ARCH_CLOCKSOURCE_DATA
 24         select ARCH_DISCARD_MEMBLOCK
 25         select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 26         select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
 27         select ARCH_HAS_DEVMEM_IS_ALLOWED
 28         select ARCH_HAS_ELF_RANDOMIZE
 29         select ARCH_HAS_FAST_MULTIPLIER
 30         select ARCH_HAS_GCOV_PROFILE_ALL
 31         select ARCH_HAS_PMEM_API                if X86_64
 32         select ARCH_HAS_MMIO_FLUSH
 33         select ARCH_HAS_SG_CHAIN
 34         select ARCH_HAS_UBSAN_SANITIZE_ALL
 35         select ARCH_HAVE_NMI_SAFE_CMPXCHG
 36         select ARCH_MIGHT_HAVE_ACPI_PDC         if ACPI
 37         select ARCH_MIGHT_HAVE_PC_PARPORT
 38         select ARCH_MIGHT_HAVE_PC_SERIO
 39         select ARCH_SUPPORTS_ATOMIC_RMW
 40         select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
 41         select ARCH_SUPPORTS_INT128             if X86_64
 42         select ARCH_SUPPORTS_NUMA_BALANCING     if X86_64
 43         select ARCH_USE_BUILTIN_BSWAP
 44         select ARCH_USE_CMPXCHG_LOCKREF         if X86_64
 45         select ARCH_USE_QUEUED_RWLOCKS
 46         select ARCH_USE_QUEUED_SPINLOCKS
 47         select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
 48         select ARCH_WANTS_DYNAMIC_TASK_STRUCT
 49         select ARCH_WANT_FRAME_POINTERS
 50         select ARCH_WANT_IPC_PARSE_VERSION      if X86_32
 51         select ARCH_WANT_OPTIONAL_GPIOLIB
 52         select BUILDTIME_EXTABLE_SORT
 53         select CLKEVT_I8253
 54         select CLKSRC_I8253                     if X86_32
 55         select CLOCKSOURCE_VALIDATE_LAST_CYCLE
 56         select CLOCKSOURCE_WATCHDOG
 57         select CLONE_BACKWARDS                  if X86_32
 58         select COMPAT_OLD_SIGACTION             if IA32_EMULATION
 59         select DCACHE_WORD_ACCESS
 60         select EDAC_ATOMIC_SCRUB
 61         select EDAC_SUPPORT
 62         select GENERIC_CLOCKEVENTS
 63         select GENERIC_CLOCKEVENTS_BROADCAST    if X86_64 || (X86_32 && X86_LOCAL_APIC)
 64         select GENERIC_CLOCKEVENTS_MIN_ADJUST
 65         select GENERIC_CMOS_UPDATE
 66         select GENERIC_CPU_AUTOPROBE
 67         select GENERIC_EARLY_IOREMAP
 68         select GENERIC_FIND_FIRST_BIT
 69         select GENERIC_IOMAP
 70         select GENERIC_IRQ_PROBE
 71         select GENERIC_IRQ_SHOW
 72         select GENERIC_PENDING_IRQ              if SMP
 73         select GENERIC_SMP_IDLE_THREAD
 74         select GENERIC_STRNCPY_FROM_USER
 75         select GENERIC_STRNLEN_USER
 76         select GENERIC_TIME_VSYSCALL
 77         select HAVE_ACPI_APEI                   if ACPI
 78         select HAVE_ACPI_APEI_NMI               if ACPI
 79         select HAVE_ALIGNED_STRUCT_PAGE         if SLUB
 80         select HAVE_AOUT                        if X86_32
 81         select HAVE_ARCH_AUDITSYSCALL
 82         select HAVE_ARCH_HUGE_VMAP              if X86_64 || X86_PAE
 83         select HAVE_ARCH_JUMP_LABEL
 84         select HAVE_ARCH_KASAN                  if X86_64 && SPARSEMEM_VMEMMAP
 85         select HAVE_ARCH_KGDB
 86         select HAVE_ARCH_KMEMCHECK
 87         select HAVE_ARCH_MMAP_RND_BITS          if MMU
 88         select HAVE_ARCH_MMAP_RND_COMPAT_BITS   if MMU && COMPAT
 89         select HAVE_ARCH_SECCOMP_FILTER
 90         select HAVE_ARCH_SOFT_DIRTY             if X86_64
 91         select HAVE_ARCH_TRACEHOOK
 92         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 93         select HAVE_BPF_JIT                     if X86_64
 94         select HAVE_CC_STACKPROTECTOR
 95         select HAVE_CMPXCHG_DOUBLE
 96         select HAVE_CMPXCHG_LOCAL
 97         select HAVE_CONTEXT_TRACKING            if X86_64
 98         select HAVE_COPY_THREAD_TLS
 99         select HAVE_C_RECORDMCOUNT
100         select HAVE_DEBUG_KMEMLEAK
101         select HAVE_DEBUG_STACKOVERFLOW
102         select HAVE_DMA_API_DEBUG
103         select HAVE_DMA_CONTIGUOUS
104         select HAVE_DYNAMIC_FTRACE
105         select HAVE_DYNAMIC_FTRACE_WITH_REGS
106         select HAVE_EFFICIENT_UNALIGNED_ACCESS
107         select HAVE_FENTRY                      if X86_64
108         select HAVE_FTRACE_MCOUNT_RECORD
109         select HAVE_FUNCTION_GRAPH_FP_TEST
110         select HAVE_FUNCTION_GRAPH_TRACER
111         select HAVE_FUNCTION_TRACER
112         select HAVE_GENERIC_DMA_COHERENT        if X86_32
113         select HAVE_HW_BREAKPOINT
114         select HAVE_IDE
115         select HAVE_IOREMAP_PROT
116         select HAVE_IRQ_EXIT_ON_IRQ_STACK       if X86_64
117         select HAVE_IRQ_TIME_ACCOUNTING
118         select HAVE_KERNEL_BZIP2
119         select HAVE_KERNEL_GZIP
120         select HAVE_KERNEL_LZ4
121         select HAVE_KERNEL_LZMA
122         select HAVE_KERNEL_LZO
123         select HAVE_KERNEL_XZ
124         select HAVE_KPROBES
125         select HAVE_KPROBES_ON_FTRACE
126         select HAVE_KRETPROBES
127         select HAVE_KVM
128         select HAVE_LIVEPATCH                   if X86_64
129         select HAVE_MEMBLOCK
130         select HAVE_MEMBLOCK_NODE_MAP
131         select HAVE_MIXED_BREAKPOINTS_REGS
132         select HAVE_OPROFILE
133         select HAVE_OPTPROBES
134         select HAVE_PCSPKR_PLATFORM
135         select HAVE_PERF_EVENTS
136         select HAVE_PERF_EVENTS_NMI
137         select HAVE_PERF_REGS
138         select HAVE_PERF_USER_STACK_DUMP
139         select HAVE_REGS_AND_STACK_ACCESS_API
140         select HAVE_SYSCALL_TRACEPOINTS
141         select HAVE_UID16                       if X86_32 || IA32_EMULATION
142         select HAVE_UNSTABLE_SCHED_CLOCK
143         select HAVE_USER_RETURN_NOTIFIER
144         select IRQ_FORCED_THREADING
145         select MODULES_USE_ELF_RELA             if X86_64
146         select MODULES_USE_ELF_REL              if X86_32
147         select OLD_SIGACTION                    if X86_32
148         select OLD_SIGSUSPEND3                  if X86_32 || IA32_EMULATION
149         select PERF_EVENTS
150         select RTC_LIB
151         select SPARSE_IRQ
152         select SRCU
153         select SYSCTL_EXCEPTION_TRACE
154         select USER_STACKTRACE_SUPPORT
155         select VIRT_TO_BUS
156         select X86_DEV_DMA_OPS                  if X86_64
157         select X86_FEATURE_NAMES                if PROC_FS
158 
159 config INSTRUCTION_DECODER
160         def_bool y
161         depends on KPROBES || PERF_EVENTS || UPROBES
162 
163 config PERF_EVENTS_INTEL_UNCORE
164         def_bool y
165         depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
166 
167 config OUTPUT_FORMAT
168         string
169         default "elf32-i386" if X86_32
170         default "elf64-x86-64" if X86_64
171 
172 config ARCH_DEFCONFIG
173         string
174         default "arch/x86/configs/i386_defconfig" if X86_32
175         default "arch/x86/configs/x86_64_defconfig" if X86_64
176 
177 config LOCKDEP_SUPPORT
178         def_bool y
179 
180 config STACKTRACE_SUPPORT
181         def_bool y
182 
183 config MMU
184         def_bool y
185 
186 config ARCH_MMAP_RND_BITS_MIN
187         default 28 if 64BIT
188         default 8
189 
190 config ARCH_MMAP_RND_BITS_MAX
191         default 32 if 64BIT
192         default 16
193 
194 config ARCH_MMAP_RND_COMPAT_BITS_MIN
195         default 8
196 
197 config ARCH_MMAP_RND_COMPAT_BITS_MAX
198         default 16
199 
200 config SBUS
201         bool
202 
203 config NEED_DMA_MAP_STATE
204         def_bool y
205         depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
206 
207 config NEED_SG_DMA_LENGTH
208         def_bool y
209 
210 config GENERIC_ISA_DMA
211         def_bool y
212         depends on ISA_DMA_API
213 
214 config GENERIC_BUG
215         def_bool y
216         depends on BUG
217         select GENERIC_BUG_RELATIVE_POINTERS if X86_64
218 
219 config GENERIC_BUG_RELATIVE_POINTERS
220         bool
221 
222 config GENERIC_HWEIGHT
223         def_bool y
224 
225 config ARCH_MAY_HAVE_PC_FDC
226         def_bool y
227         depends on ISA_DMA_API
228 
229 config RWSEM_XCHGADD_ALGORITHM
230         def_bool y
231 
232 config GENERIC_CALIBRATE_DELAY
233         def_bool y
234 
235 config ARCH_HAS_CPU_RELAX
236         def_bool y
237 
238 config ARCH_HAS_CACHE_LINE_SIZE
239         def_bool y
240 
241 config HAVE_SETUP_PER_CPU_AREA
242         def_bool y
243 
244 config NEED_PER_CPU_EMBED_FIRST_CHUNK
245         def_bool y
246 
247 config NEED_PER_CPU_PAGE_FIRST_CHUNK
248         def_bool y
249 
250 config ARCH_HIBERNATION_POSSIBLE
251         def_bool y
252 
253 config ARCH_SUSPEND_POSSIBLE
254         def_bool y
255 
256 config ARCH_WANT_HUGE_PMD_SHARE
257         def_bool y
258 
259 config ARCH_WANT_GENERAL_HUGETLB
260         def_bool y
261 
262 config ZONE_DMA32
263         def_bool y if X86_64
264 
265 config AUDIT_ARCH
266         def_bool y if X86_64
267 
268 config ARCH_SUPPORTS_OPTIMIZED_INLINING
269         def_bool y
270 
271 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
272         def_bool y
273 
274 config KASAN_SHADOW_OFFSET
275         hex
276         depends on KASAN
277         default 0xdffffc0000000000
278 
279 config HAVE_INTEL_TXT
280         def_bool y
281         depends on INTEL_IOMMU && ACPI
282 
283 config X86_32_SMP
284         def_bool y
285         depends on X86_32 && SMP
286 
287 config X86_64_SMP
288         def_bool y
289         depends on X86_64 && SMP
290 
291 config X86_32_LAZY_GS
292         def_bool y
293         depends on X86_32 && !CC_STACKPROTECTOR
294 
295 config ARCH_HWEIGHT_CFLAGS
296         string
297         default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
298         default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
299 
300 config ARCH_SUPPORTS_UPROBES
301         def_bool y
302 
303 config FIX_EARLYCON_MEM
304         def_bool y
305 
306 config PGTABLE_LEVELS
307         int
308         default 4 if X86_64
309         default 3 if X86_PAE
310         default 2
311 
312 source "init/Kconfig"
313 source "kernel/Kconfig.freezer"
314 
315 menu "Processor type and features"
316 
317 config ZONE_DMA
318         bool "DMA memory allocation support" if EXPERT
319         default y
320         help
321           DMA memory allocation support allows devices with less than 32-bit
322           addressing to allocate within the first 16MB of address space.
323           Disable if no such devices will be used.
324 
325           If unsure, say Y.
326 
327 config SMP
328         bool "Symmetric multi-processing support"
329         ---help---
330           This enables support for systems with more than one CPU. If you have
331           a system with only one CPU, say N. If you have a system with more
332           than one CPU, say Y.
333 
334           If you say N here, the kernel will run on uni- and multiprocessor
335           machines, but will use only one CPU of a multiprocessor machine. If
336           you say Y here, the kernel will run on many, but not all,
337           uniprocessor machines. On a uniprocessor machine, the kernel
338           will run faster if you say N here.
339 
340           Note that if you say Y here and choose architecture "586" or
341           "Pentium" under "Processor family", the kernel will not work on 486
342           architectures. Similarly, multiprocessor kernels for the "PPro"
343           architecture may not work on all Pentium based boards.
344 
345           People using multiprocessor machines who say Y here should also say
346           Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
347           Management" code will be disabled if you say Y here.
348 
349           See also <file:Documentation/x86/i386/IO-APIC.txt>,
350           <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
351           <http://www.tldp.org/docs.html#howto>.
352 
353           If you don't know what to do here, say N.
354 
355 config X86_FEATURE_NAMES
356         bool "Processor feature human-readable names" if EMBEDDED
357         default y
358         ---help---
359           This option compiles in a table of x86 feature bits and corresponding
360           names.  This is required to support /proc/cpuinfo and a few kernel
361           messages.  You can disable this to save space, at the expense of
362           making those few kernel messages show numeric feature bits instead.
363 
364           If in doubt, say Y.
365 
366 config X86_FAST_FEATURE_TESTS
367         bool "Fast CPU feature tests" if EMBEDDED
368         default y
369         ---help---
370           Some fast-paths in the kernel depend on the capabilities of the CPU.
371           Say Y here for the kernel to patch in the appropriate code at runtime
372           based on the capabilities of the CPU. The infrastructure for patching
373           code at runtime takes up some additional space; space-constrained
374           embedded systems may wish to say N here to produce smaller, slightly
375           slower code.
376 
377 config X86_X2APIC
378         bool "Support x2apic"
379         depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
380         ---help---
381           This enables x2apic support on CPUs that have this feature.
382 
383           This allows 32-bit apic IDs (so it can support very large systems),
384           and accesses the local apic via MSRs not via mmio.
385 
386           If you don't know what to do here, say N.
387 
388 config X86_MPPARSE
389         bool "Enable MPS table" if ACPI || SFI
390         default y
391         depends on X86_LOCAL_APIC
392         ---help---
393           For old smp systems that do not have proper acpi support. Newer systems
394           (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
395 
396 config X86_BIGSMP
397         bool "Support for big SMP systems with more than 8 CPUs"
398         depends on X86_32 && SMP
399         ---help---
400           This option is needed for the systems that have more than 8 CPUs
401 
402 config GOLDFISH
403        def_bool y
404        depends on X86_GOLDFISH
405 
406 if X86_32
407 config X86_EXTENDED_PLATFORM
408         bool "Support for extended (non-PC) x86 platforms"
409         default y
410         ---help---
411           If you disable this option then the kernel will only support
412           standard PC platforms. (which covers the vast majority of
413           systems out there.)
414 
415           If you enable this option then you'll be able to select support
416           for the following (non-PC) 32 bit x86 platforms:
417                 Goldfish (Android emulator)
418                 AMD Elan
419                 RDC R-321x SoC
420                 SGI 320/540 (Visual Workstation)
421                 STA2X11-based (e.g. Northville)
422                 Moorestown MID devices
423 
424           If you have one of these systems, or if you want to build a
425           generic distribution kernel, say Y here - otherwise say N.
426 endif
427 
428 if X86_64
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) 64 bit x86 platforms:
439                 Numascale NumaChip
440                 ScaleMP vSMP
441                 SGI Ultraviolet
442 
443           If you have one of these systems, or if you want to build a
444           generic distribution kernel, say Y here - otherwise say N.
445 endif
446 # This is an alphabetically sorted list of 64 bit extended platforms
447 # Please maintain the alphabetic order if and when there are additions
448 config X86_NUMACHIP
449         bool "Numascale NumaChip"
450         depends on X86_64
451         depends on X86_EXTENDED_PLATFORM
452         depends on NUMA
453         depends on SMP
454         depends on X86_X2APIC
455         depends on PCI_MMCONFIG
456         ---help---
457           Adds support for Numascale NumaChip large-SMP systems. Needed to
458           enable more than ~168 cores.
459           If you don't have one of these, you should say N here.
460 
461 config X86_VSMP
462         bool "ScaleMP vSMP"
463         select HYPERVISOR_GUEST
464         select PARAVIRT
465         depends on X86_64 && PCI
466         depends on X86_EXTENDED_PLATFORM
467         depends on SMP
468         ---help---
469           Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
470           supposed to run on these EM64T-based machines.  Only choose this option
471           if you have one of these machines.
472 
473 config X86_UV
474         bool "SGI Ultraviolet"
475         depends on X86_64
476         depends on X86_EXTENDED_PLATFORM
477         depends on NUMA
478         depends on EFI
479         depends on X86_X2APIC
480         depends on PCI
481         ---help---
482           This option is needed in order to support SGI Ultraviolet systems.
483           If you don't have one of these, you should say N here.
484 
485 # Following is an alphabetically sorted list of 32 bit extended platforms
486 # Please maintain the alphabetic order if and when there are additions
487 
488 config X86_GOLDFISH
489        bool "Goldfish (Virtual Platform)"
490        depends on X86_EXTENDED_PLATFORM
491        ---help---
492          Enable support for the Goldfish virtual platform used primarily
493          for Android development. Unless you are building for the Android
494          Goldfish emulator say N here.
495 
496 config X86_INTEL_CE
497         bool "CE4100 TV platform"
498         depends on PCI
499         depends on PCI_GODIRECT
500         depends on X86_IO_APIC
501         depends on X86_32
502         depends on X86_EXTENDED_PLATFORM
503         select X86_REBOOTFIXUPS
504         select OF
505         select OF_EARLY_FLATTREE
506         ---help---
507           Select for the Intel CE media processor (CE4100) SOC.
508           This option compiles in support for the CE4100 SOC for settop
509           boxes and media devices.
510 
511 config X86_INTEL_MID
512         bool "Intel MID platform support"
513         depends on X86_EXTENDED_PLATFORM
514         depends on X86_PLATFORM_DEVICES
515         depends on PCI
516         depends on X86_64 || (PCI_GOANY && X86_32)
517         depends on X86_IO_APIC
518         select SFI
519         select I2C
520         select DW_APB_TIMER
521         select APB_TIMER
522         select INTEL_SCU_IPC
523         select MFD_INTEL_MSIC
524         ---help---
525           Select to build a kernel capable of supporting Intel MID (Mobile
526           Internet Device) platform systems which do not have the PCI legacy
527           interfaces. If you are building for a PC class system say N here.
528 
529           Intel MID platforms are based on an Intel processor and chipset which
530           consume less power than most of the x86 derivatives.
531 
532 config X86_INTEL_QUARK
533         bool "Intel Quark platform support"
534         depends on X86_32
535         depends on X86_EXTENDED_PLATFORM
536         depends on X86_PLATFORM_DEVICES
537         depends on X86_TSC
538         depends on PCI
539         depends on PCI_GOANY
540         depends on X86_IO_APIC
541         select IOSF_MBI
542         select INTEL_IMR
543         select COMMON_CLK
544         ---help---
545           Select to include support for Quark X1000 SoC.
546           Say Y here if you have a Quark based system such as the Arduino
547           compatible Intel Galileo.
548 
549 config X86_INTEL_LPSS
550         bool "Intel Low Power Subsystem Support"
551         depends on X86 && ACPI
552         select COMMON_CLK
553         select PINCTRL
554         select IOSF_MBI
555         ---help---
556           Select to build support for Intel Low Power Subsystem such as
557           found on Intel Lynxpoint PCH. Selecting this option enables
558           things like clock tree (common clock framework) and pincontrol
559           which are needed by the LPSS peripheral drivers.
560 
561 config X86_AMD_PLATFORM_DEVICE
562         bool "AMD ACPI2Platform devices support"
563         depends on ACPI
564         select COMMON_CLK
565         select PINCTRL
566         ---help---
567           Select to interpret AMD specific ACPI device to platform device
568           such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
569           I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
570           implemented under PINCTRL subsystem.
571 
572 config IOSF_MBI
573         tristate "Intel SoC IOSF Sideband support for SoC platforms"
574         depends on PCI
575         ---help---
576           This option enables sideband register access support for Intel SoC
577           platforms. On these platforms the IOSF sideband is used in lieu of
578           MSR's for some register accesses, mostly but not limited to thermal
579           and power. Drivers may query the availability of this device to
580           determine if they need the sideband in order to work on these
581           platforms. The sideband is available on the following SoC products.
582           This list is not meant to be exclusive.
583            - BayTrail
584            - Braswell
585            - Quark
586 
587           You should say Y if you are running a kernel on one of these SoC's.
588 
589 config IOSF_MBI_DEBUG
590         bool "Enable IOSF sideband access through debugfs"
591         depends on IOSF_MBI && DEBUG_FS
592         ---help---
593           Select this option to expose the IOSF sideband access registers (MCR,
594           MDR, MCRX) through debugfs to write and read register information from
595           different units on the SoC. This is most useful for obtaining device
596           state information for debug and analysis. As this is a general access
597           mechanism, users of this option would have specific knowledge of the
598           device they want to access.
599 
600           If you don't require the option or are in doubt, say N.
601 
602 config X86_RDC321X
603         bool "RDC R-321x SoC"
604         depends on X86_32
605         depends on X86_EXTENDED_PLATFORM
606         select M486
607         select X86_REBOOTFIXUPS
608         ---help---
609           This option is needed for RDC R-321x system-on-chip, also known
610           as R-8610-(G).
611           If you don't have one of these chips, you should say N here.
612 
613 config X86_32_NON_STANDARD
614         bool "Support non-standard 32-bit SMP architectures"
615         depends on X86_32 && SMP
616         depends on X86_EXTENDED_PLATFORM
617         ---help---
618           This option compiles in the bigsmp and STA2X11 default
619           subarchitectures.  It is intended for a generic binary
620           kernel. If you select them all, kernel will probe it one by
621           one and will fallback to default.
622 
623 # Alphabetically sorted list of Non standard 32 bit platforms
624 
625 config X86_SUPPORTS_MEMORY_FAILURE
626         def_bool y
627         # MCE code calls memory_failure():
628         depends on X86_MCE
629         # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
630         # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
631         depends on X86_64 || !SPARSEMEM
632         select ARCH_SUPPORTS_MEMORY_FAILURE
633 
634 config STA2X11
635         bool "STA2X11 Companion Chip Support"
636         depends on X86_32_NON_STANDARD && PCI
637         select X86_DEV_DMA_OPS
638         select X86_DMA_REMAP
639         select SWIOTLB
640         select MFD_STA2X11
641         select ARCH_REQUIRE_GPIOLIB
642         default n
643         ---help---
644           This adds support for boards based on the STA2X11 IO-Hub,
645           a.k.a. "ConneXt". The chip is used in place of the standard
646           PC chipset, so all "standard" peripherals are missing. If this
647           option is selected the kernel will still be able to boot on
648           standard PC machines.
649 
650 config X86_32_IRIS
651         tristate "Eurobraille/Iris poweroff module"
652         depends on X86_32
653         ---help---
654           The Iris machines from EuroBraille do not have APM or ACPI support
655           to shut themselves down properly.  A special I/O sequence is
656           needed to do so, which is what this module does at
657           kernel shutdown.
658 
659           This is only for Iris machines from EuroBraille.
660 
661           If unused, say N.
662 
663 config SCHED_OMIT_FRAME_POINTER
664         def_bool y
665         prompt "Single-depth WCHAN output"
666         depends on X86
667         ---help---
668           Calculate simpler /proc/<PID>/wchan values. If this option
669           is disabled then wchan values will recurse back to the
670           caller function. This provides more accurate wchan values,
671           at the expense of slightly more scheduling overhead.
672 
673           If in doubt, say "Y".
674 
675 menuconfig HYPERVISOR_GUEST
676         bool "Linux guest support"
677         ---help---
678           Say Y here to enable options for running Linux under various hyper-
679           visors. This option enables basic hypervisor detection and platform
680           setup.
681 
682           If you say N, all options in this submenu will be skipped and
683           disabled, and Linux guest support won't be built in.
684 
685 if HYPERVISOR_GUEST
686 
687 config PARAVIRT
688         bool "Enable paravirtualization code"
689         ---help---
690           This changes the kernel so it can modify itself when it is run
691           under a hypervisor, potentially improving performance significantly
692           over full virtualization.  However, when run without a hypervisor
693           the kernel is theoretically slower and slightly larger.
694 
695 config PARAVIRT_DEBUG
696         bool "paravirt-ops debugging"
697         depends on PARAVIRT && DEBUG_KERNEL
698         ---help---
699           Enable to debug paravirt_ops internals.  Specifically, BUG if
700           a paravirt_op is missing when it is called.
701 
702 config PARAVIRT_SPINLOCKS
703         bool "Paravirtualization layer for spinlocks"
704         depends on PARAVIRT && SMP
705         select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
706         ---help---
707           Paravirtualized spinlocks allow a pvops backend to replace the
708           spinlock implementation with something virtualization-friendly
709           (for example, block the virtual CPU rather than spinning).
710 
711           It has a minimal impact on native kernels and gives a nice performance
712           benefit on paravirtualized KVM / Xen kernels.
713 
714           If you are unsure how to answer this question, answer Y.
715 
716 config QUEUED_LOCK_STAT
717         bool "Paravirt queued spinlock statistics"
718         depends on PARAVIRT_SPINLOCKS && DEBUG_FS && QUEUED_SPINLOCKS
719         ---help---
720           Enable the collection of statistical data on the slowpath
721           behavior of paravirtualized queued spinlocks and report
722           them on debugfs.
723 
724 source "arch/x86/xen/Kconfig"
725 
726 config KVM_GUEST
727         bool "KVM Guest support (including kvmclock)"
728         depends on PARAVIRT
729         select PARAVIRT_CLOCK
730         default y
731         ---help---
732           This option enables various optimizations for running under the KVM
733           hypervisor. It includes a paravirtualized clock, so that instead
734           of relying on a PIT (or probably other) emulation by the
735           underlying device model, the host provides the guest with
736           timing infrastructure such as time of day, and system time
737 
738 config KVM_DEBUG_FS
739         bool "Enable debug information for KVM Guests in debugfs"
740         depends on KVM_GUEST && DEBUG_FS
741         default n
742         ---help---
743           This option enables collection of various statistics for KVM guest.
744           Statistics are displayed in debugfs filesystem. Enabling this option
745           may incur significant overhead.
746 
747 source "arch/x86/lguest/Kconfig"
748 
749 config PARAVIRT_TIME_ACCOUNTING
750         bool "Paravirtual steal time accounting"
751         depends on PARAVIRT
752         default n
753         ---help---
754           Select this option to enable fine granularity task steal time
755           accounting. Time spent executing other tasks in parallel with
756           the current vCPU is discounted from the vCPU power. To account for
757           that, there can be a small performance impact.
758 
759           If in doubt, say N here.
760 
761 config PARAVIRT_CLOCK
762         bool
763 
764 endif #HYPERVISOR_GUEST
765 
766 config NO_BOOTMEM
767         def_bool y
768 
769 source "arch/x86/Kconfig.cpu"
770 
771 config HPET_TIMER
772         def_bool X86_64
773         prompt "HPET Timer Support" if X86_32
774         ---help---
775           Use the IA-PC HPET (High Precision Event Timer) to manage
776           time in preference to the PIT and RTC, if a HPET is
777           present.
778           HPET is the next generation timer replacing legacy 8254s.
779           The HPET provides a stable time base on SMP
780           systems, unlike the TSC, but it is more expensive to access,
781           as it is off-chip.  The interface used is documented
782           in the HPET spec, revision 1.
783 
784           You can safely choose Y here.  However, HPET will only be
785           activated if the platform and the BIOS support this feature.
786           Otherwise the 8254 will be used for timing services.
787 
788           Choose N to continue using the legacy 8254 timer.
789 
790 config HPET_EMULATE_RTC
791         def_bool y
792         depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
793 
794 config APB_TIMER
795        def_bool y if X86_INTEL_MID
796        prompt "Intel MID APB Timer Support" if X86_INTEL_MID
797        select DW_APB_TIMER
798        depends on X86_INTEL_MID && SFI
799        help
800          APB timer is the replacement for 8254, HPET on X86 MID platforms.
801          The APBT provides a stable time base on SMP
802          systems, unlike the TSC, but it is more expensive to access,
803          as it is off-chip. APB timers are always running regardless of CPU
804          C states, they are used as per CPU clockevent device when possible.
805 
806 # Mark as expert because too many people got it wrong.
807 # The code disables itself when not needed.
808 config DMI
809         default y
810         select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
811         bool "Enable DMI scanning" if EXPERT
812         ---help---
813           Enabled scanning of DMI to identify machine quirks. Say Y
814           here unless you have verified that your setup is not
815           affected by entries in the DMI blacklist. Required by PNP
816           BIOS code.
817 
818 config GART_IOMMU
819         bool "Old AMD GART IOMMU support"
820         select SWIOTLB
821         depends on X86_64 && PCI && AMD_NB
822         ---help---
823           Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
824           GART based hardware IOMMUs.
825 
826           The GART supports full DMA access for devices with 32-bit access
827           limitations, on systems with more than 3 GB. This is usually needed
828           for USB, sound, many IDE/SATA chipsets and some other devices.
829 
830           Newer systems typically have a modern AMD IOMMU, supported via
831           the CONFIG_AMD_IOMMU=y config option.
832 
833           In normal configurations this driver is only active when needed:
834           there's more than 3 GB of memory and the system contains a
835           32-bit limited device.
836 
837           If unsure, say Y.
838 
839 config CALGARY_IOMMU
840         bool "IBM Calgary IOMMU support"
841         select SWIOTLB
842         depends on X86_64 && PCI
843         ---help---
844           Support for hardware IOMMUs in IBM's xSeries x366 and x460
845           systems. Needed to run systems with more than 3GB of memory
846           properly with 32-bit PCI devices that do not support DAC
847           (Double Address Cycle). Calgary also supports bus level
848           isolation, where all DMAs pass through the IOMMU.  This
849           prevents them from going anywhere except their intended
850           destination. This catches hard-to-find kernel bugs and
851           mis-behaving drivers and devices that do not use the DMA-API
852           properly to set up their DMA buffers.  The IOMMU can be
853           turned off at boot time with the iommu=off parameter.
854           Normally the kernel will make the right choice by itself.
855           If unsure, say Y.
856 
857 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
858         def_bool y
859         prompt "Should Calgary be enabled by default?"
860         depends on CALGARY_IOMMU
861         ---help---
862           Should Calgary be enabled by default? if you choose 'y', Calgary
863           will be used (if it exists). If you choose 'n', Calgary will not be
864           used even if it exists. If you choose 'n' and would like to use
865           Calgary anyway, pass 'iommu=calgary' on the kernel command line.
866           If unsure, say Y.
867 
868 # need this always selected by IOMMU for the VIA workaround
869 config SWIOTLB
870         def_bool y if X86_64
871         ---help---
872           Support for software bounce buffers used on x86-64 systems
873           which don't have a hardware IOMMU. Using this PCI devices
874           which can only access 32-bits of memory can be used on systems
875           with more than 3 GB of memory.
876           If unsure, say Y.
877 
878 config IOMMU_HELPER
879         def_bool y
880         depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
881 
882 config MAXSMP
883         bool "Enable Maximum number of SMP Processors and NUMA Nodes"
884         depends on X86_64 && SMP && DEBUG_KERNEL
885         select CPUMASK_OFFSTACK
886         ---help---
887           Enable maximum number of CPUS and NUMA Nodes for this architecture.
888           If unsure, say N.
889 
890 config NR_CPUS
891         int "Maximum number of CPUs" if SMP && !MAXSMP
892         range 2 8 if SMP && X86_32 && !X86_BIGSMP
893         range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
894         range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
895         default "1" if !SMP
896         default "8192" if MAXSMP
897         default "32" if SMP && X86_BIGSMP
898         default "8" if SMP && X86_32
899         default "64" if SMP
900         ---help---
901           This allows you to specify the maximum number of CPUs which this
902           kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
903           supported value is 8192, otherwise the maximum value is 512.  The
904           minimum value which makes sense is 2.
905 
906           This is purely to save memory - each supported CPU adds
907           approximately eight kilobytes to the kernel image.
908 
909 config SCHED_SMT
910         bool "SMT (Hyperthreading) scheduler support"
911         depends on SMP
912         ---help---
913           SMT scheduler support improves the CPU scheduler's decision making
914           when dealing with Intel Pentium 4 chips with HyperThreading at a
915           cost of slightly increased overhead in some places. If unsure say
916           N here.
917 
918 config SCHED_MC
919         def_bool y
920         prompt "Multi-core scheduler support"
921         depends on SMP
922         ---help---
923           Multi-core scheduler support improves the CPU scheduler's decision
924           making when dealing with multi-core CPU chips at a cost of slightly
925           increased overhead in some places. If unsure say N here.
926 
927 source "kernel/Kconfig.preempt"
928 
929 config UP_LATE_INIT
930        def_bool y
931        depends on !SMP && X86_LOCAL_APIC
932 
933 config X86_UP_APIC
934         bool "Local APIC support on uniprocessors" if !PCI_MSI
935         default PCI_MSI
936         depends on X86_32 && !SMP && !X86_32_NON_STANDARD
937         ---help---
938           A local APIC (Advanced Programmable Interrupt Controller) is an
939           integrated interrupt controller in the CPU. If you have a single-CPU
940           system which has a processor with a local APIC, you can say Y here to
941           enable and use it. If you say Y here even though your machine doesn't
942           have a local APIC, then the kernel will still run with no slowdown at
943           all. The local APIC supports CPU-generated self-interrupts (timer,
944           performance counters), and the NMI watchdog which detects hard
945           lockups.
946 
947 config X86_UP_IOAPIC
948         bool "IO-APIC support on uniprocessors"
949         depends on X86_UP_APIC
950         ---help---
951           An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
952           SMP-capable replacement for PC-style interrupt controllers. Most
953           SMP systems and many recent uniprocessor systems have one.
954 
955           If you have a single-CPU system with an IO-APIC, you can say Y here
956           to use it. If you say Y here even though your machine doesn't have
957           an IO-APIC, then the kernel will still run with no slowdown at all.
958 
959 config X86_LOCAL_APIC
960         def_bool y
961         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
962         select IRQ_DOMAIN_HIERARCHY
963         select PCI_MSI_IRQ_DOMAIN if PCI_MSI
964 
965 config X86_IO_APIC
966         def_bool y
967         depends on X86_LOCAL_APIC || X86_UP_IOAPIC
968 
969 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
970         bool "Reroute for broken boot IRQs"
971         depends on X86_IO_APIC
972         ---help---
973           This option enables a workaround that fixes a source of
974           spurious interrupts. This is recommended when threaded
975           interrupt handling is used on systems where the generation of
976           superfluous "boot interrupts" cannot be disabled.
977 
978           Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
979           entry in the chipset's IO-APIC is masked (as, e.g. the RT
980           kernel does during interrupt handling). On chipsets where this
981           boot IRQ generation cannot be disabled, this workaround keeps
982           the original IRQ line masked so that only the equivalent "boot
983           IRQ" is delivered to the CPUs. The workaround also tells the
984           kernel to set up the IRQ handler on the boot IRQ line. In this
985           way only one interrupt is delivered to the kernel. Otherwise
986           the spurious second interrupt may cause the kernel to bring
987           down (vital) interrupt lines.
988 
989           Only affects "broken" chipsets. Interrupt sharing may be
990           increased on these systems.
991 
992 config X86_MCE
993         bool "Machine Check / overheating reporting"
994         select GENERIC_ALLOCATOR
995         default y
996         ---help---
997           Machine Check support allows the processor to notify the
998           kernel if it detects a problem (e.g. overheating, data corruption).
999           The action the kernel takes depends on the severity of the problem,
1000           ranging from warning messages to halting the machine.
1001 
1002 config X86_MCE_INTEL
1003         def_bool y
1004         prompt "Intel MCE features"
1005         depends on X86_MCE && X86_LOCAL_APIC
1006         ---help---
1007            Additional support for intel specific MCE features such as
1008            the thermal monitor.
1009 
1010 config X86_MCE_AMD
1011         def_bool y
1012         prompt "AMD MCE features"
1013         depends on X86_MCE && X86_LOCAL_APIC
1014         ---help---
1015            Additional support for AMD specific MCE features such as
1016            the DRAM Error Threshold.
1017 
1018 config X86_ANCIENT_MCE
1019         bool "Support for old Pentium 5 / WinChip machine checks"
1020         depends on X86_32 && X86_MCE
1021         ---help---
1022           Include support for machine check handling on old Pentium 5 or WinChip
1023           systems. These typically need to be enabled explicitly on the command
1024           line.
1025 
1026 config X86_MCE_THRESHOLD
1027         depends on X86_MCE_AMD || X86_MCE_INTEL
1028         def_bool y
1029 
1030 config X86_MCE_INJECT
1031         depends on X86_MCE
1032         tristate "Machine check injector support"
1033         ---help---
1034           Provide support for injecting machine checks for testing purposes.
1035           If you don't know what a machine check is and you don't do kernel
1036           QA it is safe to say n.
1037 
1038 config X86_THERMAL_VECTOR
1039         def_bool y
1040         depends on X86_MCE_INTEL
1041 
1042 config X86_LEGACY_VM86
1043         bool "Legacy VM86 support"
1044         default n
1045         depends on X86_32
1046         ---help---
1047           This option allows user programs to put the CPU into V8086
1048           mode, which is an 80286-era approximation of 16-bit real mode.
1049 
1050           Some very old versions of X and/or vbetool require this option
1051           for user mode setting.  Similarly, DOSEMU will use it if
1052           available to accelerate real mode DOS programs.  However, any
1053           recent version of DOSEMU, X, or vbetool should be fully
1054           functional even without kernel VM86 support, as they will all
1055           fall back to software emulation. Nevertheless, if you are using
1056           a 16-bit DOS program where 16-bit performance matters, vm86
1057           mode might be faster than emulation and you might want to
1058           enable this option.
1059 
1060           Note that any app that works on a 64-bit kernel is unlikely to
1061           need this option, as 64-bit kernels don't, and can't, support
1062           V8086 mode. This option is also unrelated to 16-bit protected
1063           mode and is not needed to run most 16-bit programs under Wine.
1064 
1065           Enabling this option increases the complexity of the kernel
1066           and slows down exception handling a tiny bit.
1067 
1068           If unsure, say N here.
1069 
1070 config VM86
1071        bool
1072        default X86_LEGACY_VM86
1073 
1074 config X86_16BIT
1075         bool "Enable support for 16-bit segments" if EXPERT
1076         default y
1077         depends on MODIFY_LDT_SYSCALL
1078         ---help---
1079           This option is required by programs like Wine to run 16-bit
1080           protected mode legacy code on x86 processors.  Disabling
1081           this option saves about 300 bytes on i386, or around 6K text
1082           plus 16K runtime memory on x86-64,
1083 
1084 config X86_ESPFIX32
1085         def_bool y
1086         depends on X86_16BIT && X86_32
1087 
1088 config X86_ESPFIX64
1089         def_bool y
1090         depends on X86_16BIT && X86_64
1091 
1092 config X86_VSYSCALL_EMULATION
1093        bool "Enable vsyscall emulation" if EXPERT
1094        default y
1095        depends on X86_64
1096        ---help---
1097          This enables emulation of the legacy vsyscall page.  Disabling
1098          it is roughly equivalent to booting with vsyscall=none, except
1099          that it will also disable the helpful warning if a program
1100          tries to use a vsyscall.  With this option set to N, offending
1101          programs will just segfault, citing addresses of the form
1102          0xffffffffff600?00.
1103 
1104          This option is required by many programs built before 2013, and
1105          care should be used even with newer programs if set to N.
1106 
1107          Disabling this option saves about 7K of kernel size and
1108          possibly 4K of additional runtime pagetable memory.
1109 
1110 config TOSHIBA
1111         tristate "Toshiba Laptop support"
1112         depends on X86_32
1113         ---help---
1114           This adds a driver to safely access the System Management Mode of
1115           the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1116           not work on models with a Phoenix BIOS. The System Management Mode
1117           is used to set the BIOS and power saving options on Toshiba portables.
1118 
1119           For information on utilities to make use of this driver see the
1120           Toshiba Linux utilities web site at:
1121           <http://www.buzzard.org.uk/toshiba/>.
1122 
1123           Say Y if you intend to run this kernel on a Toshiba portable.
1124           Say N otherwise.
1125 
1126 config I8K
1127         tristate "Dell i8k legacy laptop support"
1128         select HWMON
1129         select SENSORS_DELL_SMM
1130         ---help---
1131           This option enables legacy /proc/i8k userspace interface in hwmon
1132           dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1133           temperature and allows controlling fan speeds of Dell laptops via
1134           System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1135           it reports also power and hotkey status. For fan speed control is
1136           needed userspace package i8kutils.
1137 
1138           Say Y if you intend to run this kernel on old Dell laptops or want to
1139           use userspace package i8kutils.
1140           Say N otherwise.
1141 
1142 config X86_REBOOTFIXUPS
1143         bool "Enable X86 board specific fixups for reboot"
1144         depends on X86_32
1145         ---help---
1146           This enables chipset and/or board specific fixups to be done
1147           in order to get reboot to work correctly. This is only needed on
1148           some combinations of hardware and BIOS. The symptom, for which
1149           this config is intended, is when reboot ends with a stalled/hung
1150           system.
1151 
1152           Currently, the only fixup is for the Geode machines using
1153           CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1154 
1155           Say Y if you want to enable the fixup. Currently, it's safe to
1156           enable this option even if you don't need it.
1157           Say N otherwise.
1158 
1159 config MICROCODE
1160         bool "CPU microcode loading support"
1161         default y
1162         depends on CPU_SUP_AMD || CPU_SUP_INTEL
1163         depends on BLK_DEV_INITRD
1164         select FW_LOADER
1165         ---help---
1166 
1167           If you say Y here, you will be able to update the microcode on
1168           certain Intel and AMD processors. The Intel support is for the
1169           IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1170           Xeon etc. The AMD support is for families 0x10 and later. You will
1171           obviously need the actual microcode binary data itself which is not
1172           shipped with the Linux kernel.
1173 
1174           This option selects the general module only, you need to select
1175           at least one vendor specific module as well.
1176 
1177           To compile this driver as a module, choose M here: the module
1178           will be called microcode.
1179 
1180 config MICROCODE_INTEL
1181         bool "Intel microcode loading support"
1182         depends on MICROCODE
1183         default MICROCODE
1184         select FW_LOADER
1185         ---help---
1186           This options enables microcode patch loading support for Intel
1187           processors.
1188 
1189           For the current Intel microcode data package go to
1190           <https://downloadcenter.intel.com> and search for
1191           'Linux Processor Microcode Data File'.
1192 
1193 config MICROCODE_AMD
1194         bool "AMD microcode loading support"
1195         depends on MICROCODE
1196         select FW_LOADER
1197         ---help---
1198           If you select this option, microcode patch loading support for AMD
1199           processors will be enabled.
1200 
1201 config MICROCODE_OLD_INTERFACE
1202         def_bool y
1203         depends on MICROCODE
1204 
1205 config X86_MSR
1206         tristate "/dev/cpu/*/msr - Model-specific register support"
1207         ---help---
1208           This device gives privileged processes access to the x86
1209           Model-Specific Registers (MSRs).  It is a character device with
1210           major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1211           MSR accesses are directed to a specific CPU on multi-processor
1212           systems.
1213 
1214 config X86_CPUID
1215         tristate "/dev/cpu/*/cpuid - CPU information support"
1216         ---help---
1217           This device gives processes access to the x86 CPUID instruction to
1218           be executed on a specific processor.  It is a character device
1219           with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1220           /dev/cpu/31/cpuid.
1221 
1222 choice
1223         prompt "High Memory Support"
1224         default HIGHMEM4G
1225         depends on X86_32
1226 
1227 config NOHIGHMEM
1228         bool "off"
1229         ---help---
1230           Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1231           However, the address space of 32-bit x86 processors is only 4
1232           Gigabytes large. That means that, if you have a large amount of
1233           physical memory, not all of it can be "permanently mapped" by the
1234           kernel. The physical memory that's not permanently mapped is called
1235           "high memory".
1236 
1237           If you are compiling a kernel which will never run on a machine with
1238           more than 1 Gigabyte total physical RAM, answer "off" here (default
1239           choice and suitable for most users). This will result in a "3GB/1GB"
1240           split: 3GB are mapped so that each process sees a 3GB virtual memory
1241           space and the remaining part of the 4GB virtual memory space is used
1242           by the kernel to permanently map as much physical memory as
1243           possible.
1244 
1245           If the machine has between 1 and 4 Gigabytes physical RAM, then
1246           answer "4GB" here.
1247 
1248           If more than 4 Gigabytes is used then answer "64GB" here. This
1249           selection turns Intel PAE (Physical Address Extension) mode on.
1250           PAE implements 3-level paging on IA32 processors. PAE is fully
1251           supported by Linux, PAE mode is implemented on all recent Intel
1252           processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1253           then the kernel will not boot on CPUs that don't support PAE!
1254 
1255           The actual amount of total physical memory will either be
1256           auto detected or can be forced by using a kernel command line option
1257           such as "mem=256M". (Try "man bootparam" or see the documentation of
1258           your boot loader (lilo or loadlin) about how to pass options to the
1259           kernel at boot time.)
1260 
1261           If unsure, say "off".
1262 
1263 config HIGHMEM4G
1264         bool "4GB"
1265         ---help---
1266           Select this if you have a 32-bit processor and between 1 and 4
1267           gigabytes of physical RAM.
1268 
1269 config HIGHMEM64G
1270         bool "64GB"
1271         depends on !M486
1272         select X86_PAE
1273         ---help---
1274           Select this if you have a 32-bit processor and more than 4
1275           gigabytes of physical RAM.
1276 
1277 endchoice
1278 
1279 choice
1280         prompt "Memory split" if EXPERT
1281         default VMSPLIT_3G
1282         depends on X86_32
1283         ---help---
1284           Select the desired split between kernel and user memory.
1285 
1286           If the address range available to the kernel is less than the
1287           physical memory installed, the remaining memory will be available
1288           as "high memory". Accessing high memory is a little more costly
1289           than low memory, as it needs to be mapped into the kernel first.
1290           Note that increasing the kernel address space limits the range
1291           available to user programs, making the address space there
1292           tighter.  Selecting anything other than the default 3G/1G split
1293           will also likely make your kernel incompatible with binary-only
1294           kernel modules.
1295 
1296           If you are not absolutely sure what you are doing, leave this
1297           option alone!
1298 
1299         config VMSPLIT_3G
1300                 bool "3G/1G user/kernel split"
1301         config VMSPLIT_3G_OPT
1302                 depends on !X86_PAE
1303                 bool "3G/1G user/kernel split (for full 1G low memory)"
1304         config VMSPLIT_2G
1305                 bool "2G/2G user/kernel split"
1306         config VMSPLIT_2G_OPT
1307                 depends on !X86_PAE
1308                 bool "2G/2G user/kernel split (for full 2G low memory)"
1309         config VMSPLIT_1G
1310                 bool "1G/3G user/kernel split"
1311 endchoice
1312 
1313 config PAGE_OFFSET
1314         hex
1315         default 0xB0000000 if VMSPLIT_3G_OPT
1316         default 0x80000000 if VMSPLIT_2G
1317         default 0x78000000 if VMSPLIT_2G_OPT
1318         default 0x40000000 if VMSPLIT_1G
1319         default 0xC0000000
1320         depends on X86_32
1321 
1322 config HIGHMEM
1323         def_bool y
1324         depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1325 
1326 config X86_PAE
1327         bool "PAE (Physical Address Extension) Support"
1328         depends on X86_32 && !HIGHMEM4G
1329         select SWIOTLB
1330         ---help---
1331           PAE is required for NX support, and furthermore enables
1332           larger swapspace support for non-overcommit purposes. It
1333           has the cost of more pagetable lookup overhead, and also
1334           consumes more pagetable space per process.
1335 
1336 config ARCH_PHYS_ADDR_T_64BIT
1337         def_bool y
1338         depends on X86_64 || X86_PAE
1339 
1340 config ARCH_DMA_ADDR_T_64BIT
1341         def_bool y
1342         depends on X86_64 || HIGHMEM64G
1343 
1344 config X86_DIRECT_GBPAGES
1345         def_bool y
1346         depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1347         ---help---
1348           Certain kernel features effectively disable kernel
1349           linear 1 GB mappings (even if the CPU otherwise
1350           supports them), so don't confuse the user by printing
1351           that we have them enabled.
1352 
1353 # Common NUMA Features
1354 config NUMA
1355         bool "Numa Memory Allocation and Scheduler Support"
1356         depends on SMP
1357         depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1358         default y if X86_BIGSMP
1359         ---help---
1360           Enable NUMA (Non Uniform Memory Access) support.
1361 
1362           The kernel will try to allocate memory used by a CPU on the
1363           local memory controller of the CPU and add some more
1364           NUMA awareness to the kernel.
1365 
1366           For 64-bit this is recommended if the system is Intel Core i7
1367           (or later), AMD Opteron, or EM64T NUMA.
1368 
1369           For 32-bit this is only needed if you boot a 32-bit
1370           kernel on a 64-bit NUMA platform.
1371 
1372           Otherwise, you should say N.
1373 
1374 config AMD_NUMA
1375         def_bool y
1376         prompt "Old style AMD Opteron NUMA detection"
1377         depends on X86_64 && NUMA && PCI
1378         ---help---
1379           Enable AMD NUMA node topology detection.  You should say Y here if
1380           you have a multi processor AMD system. This uses an old method to
1381           read the NUMA configuration directly from the builtin Northbridge
1382           of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1383           which also takes priority if both are compiled in.
1384 
1385 config X86_64_ACPI_NUMA
1386         def_bool y
1387         prompt "ACPI NUMA detection"
1388         depends on X86_64 && NUMA && ACPI && PCI
1389         select ACPI_NUMA
1390         ---help---
1391           Enable ACPI SRAT based node topology detection.
1392 
1393 # Some NUMA nodes have memory ranges that span
1394 # other nodes.  Even though a pfn is valid and
1395 # between a node's start and end pfns, it may not
1396 # reside on that node.  See memmap_init_zone()
1397 # for details.
1398 config NODES_SPAN_OTHER_NODES
1399         def_bool y
1400         depends on X86_64_ACPI_NUMA
1401 
1402 config NUMA_EMU
1403         bool "NUMA emulation"
1404         depends on NUMA
1405         ---help---
1406           Enable NUMA emulation. A flat machine will be split
1407           into virtual nodes when booted with "numa=fake=N", where N is the
1408           number of nodes. This is only useful for debugging.
1409 
1410 config NODES_SHIFT
1411         int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1412         range 1 10
1413         default "10" if MAXSMP
1414         default "6" if X86_64
1415         default "3"
1416         depends on NEED_MULTIPLE_NODES
1417         ---help---
1418           Specify the maximum number of NUMA Nodes available on the target
1419           system.  Increases memory reserved to accommodate various tables.
1420 
1421 config ARCH_HAVE_MEMORY_PRESENT
1422         def_bool y
1423         depends on X86_32 && DISCONTIGMEM
1424 
1425 config NEED_NODE_MEMMAP_SIZE
1426         def_bool y
1427         depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1428 
1429 config ARCH_FLATMEM_ENABLE
1430         def_bool y
1431         depends on X86_32 && !NUMA
1432 
1433 config ARCH_DISCONTIGMEM_ENABLE
1434         def_bool y
1435         depends on NUMA && X86_32
1436 
1437 config ARCH_DISCONTIGMEM_DEFAULT
1438         def_bool y
1439         depends on NUMA && X86_32
1440 
1441 config ARCH_SPARSEMEM_ENABLE
1442         def_bool y
1443         depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1444         select SPARSEMEM_STATIC if X86_32
1445         select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1446 
1447 config ARCH_SPARSEMEM_DEFAULT
1448         def_bool y
1449         depends on X86_64
1450 
1451 config ARCH_SELECT_MEMORY_MODEL
1452         def_bool y
1453         depends on ARCH_SPARSEMEM_ENABLE
1454 
1455 config ARCH_MEMORY_PROBE
1456         bool "Enable sysfs memory/probe interface"
1457         depends on X86_64 && MEMORY_HOTPLUG
1458         help
1459           This option enables a sysfs memory/probe interface for testing.
1460           See Documentation/memory-hotplug.txt for more information.
1461           If you are unsure how to answer this question, answer N.
1462 
1463 config ARCH_PROC_KCORE_TEXT
1464         def_bool y
1465         depends on X86_64 && PROC_KCORE
1466 
1467 config ILLEGAL_POINTER_VALUE
1468        hex
1469        default 0 if X86_32
1470        default 0xdead000000000000 if X86_64
1471 
1472 source "mm/Kconfig"
1473 
1474 config X86_PMEM_LEGACY_DEVICE
1475         bool
1476 
1477 config X86_PMEM_LEGACY
1478         tristate "Support non-standard NVDIMMs and ADR protected memory"
1479         depends on PHYS_ADDR_T_64BIT
1480         depends on BLK_DEV
1481         select X86_PMEM_LEGACY_DEVICE
1482         select LIBNVDIMM
1483         help
1484           Treat memory marked using the non-standard e820 type of 12 as used
1485           by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1486           The kernel will offer these regions to the 'pmem' driver so
1487           they can be used for persistent storage.
1488 
1489           Say Y if unsure.
1490 
1491 config HIGHPTE
1492         bool "Allocate 3rd-level pagetables from highmem"
1493         depends on HIGHMEM
1494         ---help---
1495           The VM uses one page table entry for each page of physical memory.
1496           For systems with a lot of RAM, this can be wasteful of precious
1497           low memory.  Setting this option will put user-space page table
1498           entries in high memory.
1499 
1500 config X86_CHECK_BIOS_CORRUPTION
1501         bool "Check for low memory corruption"
1502         ---help---
1503           Periodically check for memory corruption in low memory, which
1504           is suspected to be caused by BIOS.  Even when enabled in the
1505           configuration, it is disabled at runtime.  Enable it by
1506           setting "memory_corruption_check=1" on the kernel command
1507           line.  By default it scans the low 64k of memory every 60
1508           seconds; see the memory_corruption_check_size and
1509           memory_corruption_check_period parameters in
1510           Documentation/kernel-parameters.txt to adjust this.
1511 
1512           When enabled with the default parameters, this option has
1513           almost no overhead, as it reserves a relatively small amount
1514           of memory and scans it infrequently.  It both detects corruption
1515           and prevents it from affecting the running system.
1516 
1517           It is, however, intended as a diagnostic tool; if repeatable
1518           BIOS-originated corruption always affects the same memory,
1519           you can use memmap= to prevent the kernel from using that
1520           memory.
1521 
1522 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1523         bool "Set the default setting of memory_corruption_check"
1524         depends on X86_CHECK_BIOS_CORRUPTION
1525         default y
1526         ---help---
1527           Set whether the default state of memory_corruption_check is
1528           on or off.
1529 
1530 config X86_RESERVE_LOW
1531         int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1532         default 64
1533         range 4 640
1534         ---help---
1535           Specify the amount of low memory to reserve for the BIOS.
1536 
1537           The first page contains BIOS data structures that the kernel
1538           must not use, so that page must always be reserved.
1539 
1540           By default we reserve the first 64K of physical RAM, as a
1541           number of BIOSes are known to corrupt that memory range
1542           during events such as suspend/resume or monitor cable
1543           insertion, so it must not be used by the kernel.
1544 
1545           You can set this to 4 if you are absolutely sure that you
1546           trust the BIOS to get all its memory reservations and usages
1547           right.  If you know your BIOS have problems beyond the
1548           default 64K area, you can set this to 640 to avoid using the
1549           entire low memory range.
1550 
1551           If you have doubts about the BIOS (e.g. suspend/resume does
1552           not work or there's kernel crashes after certain hardware
1553           hotplug events) then you might want to enable
1554           X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1555           typical corruption patterns.
1556 
1557           Leave this to the default value of 64 if you are unsure.
1558 
1559 config MATH_EMULATION
1560         bool
1561         depends on MODIFY_LDT_SYSCALL
1562         prompt "Math emulation" if X86_32
1563         ---help---
1564           Linux can emulate a math coprocessor (used for floating point
1565           operations) if you don't have one. 486DX and Pentium processors have
1566           a math coprocessor built in, 486SX and 386 do not, unless you added
1567           a 487DX or 387, respectively. (The messages during boot time can
1568           give you some hints here ["man dmesg"].) Everyone needs either a
1569           coprocessor or this emulation.
1570 
1571           If you don't have a math coprocessor, you need to say Y here; if you
1572           say Y here even though you have a coprocessor, the coprocessor will
1573           be used nevertheless. (This behavior can be changed with the kernel
1574           command line option "no387", which comes handy if your coprocessor
1575           is broken. Try "man bootparam" or see the documentation of your boot
1576           loader (lilo or loadlin) about how to pass options to the kernel at
1577           boot time.) This means that it is a good idea to say Y here if you
1578           intend to use this kernel on different machines.
1579 
1580           More information about the internals of the Linux math coprocessor
1581           emulation can be found in <file:arch/x86/math-emu/README>.
1582 
1583           If you are not sure, say Y; apart from resulting in a 66 KB bigger
1584           kernel, it won't hurt.
1585 
1586 config MTRR
1587         def_bool y
1588         prompt "MTRR (Memory Type Range Register) support" if EXPERT
1589         ---help---
1590           On Intel P6 family processors (Pentium Pro, Pentium II and later)
1591           the Memory Type Range Registers (MTRRs) may be used to control
1592           processor access to memory ranges. This is most useful if you have
1593           a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1594           allows bus write transfers to be combined into a larger transfer
1595           before bursting over the PCI/AGP bus. This can increase performance
1596           of image write operations 2.5 times or more. Saying Y here creates a
1597           /proc/mtrr file which may be used to manipulate your processor's
1598           MTRRs. Typically the X server should use this.
1599 
1600           This code has a reasonably generic interface so that similar
1601           control registers on other processors can be easily supported
1602           as well:
1603 
1604           The Cyrix 6x86, 6x86MX and M II processors have Address Range
1605           Registers (ARRs) which provide a similar functionality to MTRRs. For
1606           these, the ARRs are used to emulate the MTRRs.
1607           The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1608           MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1609           write-combining. All of these processors are supported by this code
1610           and it makes sense to say Y here if you have one of them.
1611 
1612           Saying Y here also fixes a problem with buggy SMP BIOSes which only
1613           set the MTRRs for the boot CPU and not for the secondary CPUs. This
1614           can lead to all sorts of problems, so it's good to say Y here.
1615 
1616           You can safely say Y even if your machine doesn't have MTRRs, you'll
1617           just add about 9 KB to your kernel.
1618 
1619           See <file:Documentation/x86/mtrr.txt> for more information.
1620 
1621 config MTRR_SANITIZER
1622         def_bool y
1623         prompt "MTRR cleanup support"
1624         depends on MTRR
1625         ---help---
1626           Convert MTRR layout from continuous to discrete, so X drivers can
1627           add writeback entries.
1628 
1629           Can be disabled with disable_mtrr_cleanup on the kernel command line.
1630           The largest mtrr entry size for a continuous block can be set with
1631           mtrr_chunk_size.
1632 
1633           If unsure, say Y.
1634 
1635 config MTRR_SANITIZER_ENABLE_DEFAULT
1636         int "MTRR cleanup enable value (0-1)"
1637         range 0 1
1638         default "0"
1639         depends on MTRR_SANITIZER
1640         ---help---
1641           Enable mtrr cleanup default value
1642 
1643 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1644         int "MTRR cleanup spare reg num (0-7)"
1645         range 0 7
1646         default "1"
1647         depends on MTRR_SANITIZER
1648         ---help---
1649           mtrr cleanup spare entries default, it can be changed via
1650           mtrr_spare_reg_nr=N on the kernel command line.
1651 
1652 config X86_PAT
1653         def_bool y
1654         prompt "x86 PAT support" if EXPERT
1655         depends on MTRR
1656         ---help---
1657           Use PAT attributes to setup page level cache control.
1658 
1659           PATs are the modern equivalents of MTRRs and are much more
1660           flexible than MTRRs.
1661 
1662           Say N here if you see bootup problems (boot crash, boot hang,
1663           spontaneous reboots) or a non-working video driver.
1664 
1665           If unsure, say Y.
1666 
1667 config ARCH_USES_PG_UNCACHED
1668         def_bool y
1669         depends on X86_PAT
1670 
1671 config ARCH_RANDOM
1672         def_bool y
1673         prompt "x86 architectural random number generator" if EXPERT
1674         ---help---
1675           Enable the x86 architectural RDRAND instruction
1676           (Intel Bull Mountain technology) to generate random numbers.
1677           If supported, this is a high bandwidth, cryptographically
1678           secure hardware random number generator.
1679 
1680 config X86_SMAP
1681         def_bool y
1682         prompt "Supervisor Mode Access Prevention" if EXPERT
1683         ---help---
1684           Supervisor Mode Access Prevention (SMAP) is a security
1685           feature in newer Intel processors.  There is a small
1686           performance cost if this enabled and turned on; there is
1687           also a small increase in the kernel size if this is enabled.
1688 
1689           If unsure, say Y.
1690 
1691 config X86_INTEL_MPX
1692         prompt "Intel MPX (Memory Protection Extensions)"
1693         def_bool n
1694         depends on CPU_SUP_INTEL
1695         ---help---
1696           MPX provides hardware features that can be used in
1697           conjunction with compiler-instrumented code to check
1698           memory references.  It is designed to detect buffer
1699           overflow or underflow bugs.
1700 
1701           This option enables running applications which are
1702           instrumented or otherwise use MPX.  It does not use MPX
1703           itself inside the kernel or to protect the kernel
1704           against bad memory references.
1705 
1706           Enabling this option will make the kernel larger:
1707           ~8k of kernel text and 36 bytes of data on a 64-bit
1708           defconfig.  It adds a long to the 'mm_struct' which
1709           will increase the kernel memory overhead of each
1710           process and adds some branches to paths used during
1711           exec() and munmap().
1712 
1713           For details, see Documentation/x86/intel_mpx.txt
1714 
1715           If unsure, say N.
1716 
1717 config EFI
1718         bool "EFI runtime service support"
1719         depends on ACPI
1720         select UCS2_STRING
1721         select EFI_RUNTIME_WRAPPERS
1722         ---help---
1723           This enables the kernel to use EFI runtime services that are
1724           available (such as the EFI variable services).
1725 
1726           This option is only useful on systems that have EFI firmware.
1727           In addition, you should use the latest ELILO loader available
1728           at <http://elilo.sourceforge.net> in order to take advantage
1729           of EFI runtime services. However, even with this option, the
1730           resultant kernel should continue to boot on existing non-EFI
1731           platforms.
1732 
1733 config EFI_STUB
1734        bool "EFI stub support"
1735        depends on EFI && !X86_USE_3DNOW
1736        select RELOCATABLE
1737        ---help---
1738           This kernel feature allows a bzImage to be loaded directly
1739           by EFI firmware without the use of a bootloader.
1740 
1741           See Documentation/efi-stub.txt for more information.
1742 
1743 config EFI_MIXED
1744         bool "EFI mixed-mode support"
1745         depends on EFI_STUB && X86_64
1746         ---help---
1747            Enabling this feature allows a 64-bit kernel to be booted
1748            on a 32-bit firmware, provided that your CPU supports 64-bit
1749            mode.
1750 
1751            Note that it is not possible to boot a mixed-mode enabled
1752            kernel via the EFI boot stub - a bootloader that supports
1753            the EFI handover protocol must be used.
1754 
1755            If unsure, say N.
1756 
1757 config SECCOMP
1758         def_bool y
1759         prompt "Enable seccomp to safely compute untrusted bytecode"
1760         ---help---
1761           This kernel feature is useful for number crunching applications
1762           that may need to compute untrusted bytecode during their
1763           execution. By using pipes or other transports made available to
1764           the process as file descriptors supporting the read/write
1765           syscalls, it's possible to isolate those applications in
1766           their own address space using seccomp. Once seccomp is
1767           enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1768           and the task is only allowed to execute a few safe syscalls
1769           defined by each seccomp mode.
1770 
1771           If unsure, say Y. Only embedded should say N here.
1772 
1773 source kernel/Kconfig.hz
1774 
1775 config KEXEC
1776         bool "kexec system call"
1777         select KEXEC_CORE
1778         ---help---
1779           kexec is a system call that implements the ability to shutdown your
1780           current kernel, and to start another kernel.  It is like a reboot
1781           but it is independent of the system firmware.   And like a reboot
1782           you can start any kernel with it, not just Linux.
1783 
1784           The name comes from the similarity to the exec system call.
1785 
1786           It is an ongoing process to be certain the hardware in a machine
1787           is properly shutdown, so do not be surprised if this code does not
1788           initially work for you.  As of this writing the exact hardware
1789           interface is strongly in flux, so no good recommendation can be
1790           made.
1791 
1792 config KEXEC_FILE
1793         bool "kexec file based system call"
1794         select KEXEC_CORE
1795         select BUILD_BIN2C
1796         depends on X86_64
1797         depends on CRYPTO=y
1798         depends on CRYPTO_SHA256=y
1799         ---help---
1800           This is new version of kexec system call. This system call is
1801           file based and takes file descriptors as system call argument
1802           for kernel and initramfs as opposed to list of segments as
1803           accepted by previous system call.
1804 
1805 config KEXEC_VERIFY_SIG
1806         bool "Verify kernel signature during kexec_file_load() syscall"
1807         depends on KEXEC_FILE
1808         ---help---
1809           This option makes kernel signature verification mandatory for
1810           the kexec_file_load() syscall.
1811 
1812           In addition to that option, you need to enable signature
1813           verification for the corresponding kernel image type being
1814           loaded in order for this to work.
1815 
1816 config KEXEC_BZIMAGE_VERIFY_SIG
1817         bool "Enable bzImage signature verification support"
1818         depends on KEXEC_VERIFY_SIG
1819         depends on SIGNED_PE_FILE_VERIFICATION
1820         select SYSTEM_TRUSTED_KEYRING
1821         ---help---
1822           Enable bzImage signature verification support.
1823 
1824 config CRASH_DUMP
1825         bool "kernel crash dumps"
1826         depends on X86_64 || (X86_32 && HIGHMEM)
1827         ---help---
1828           Generate crash dump after being started by kexec.
1829           This should be normally only set in special crash dump kernels
1830           which are loaded in the main kernel with kexec-tools into
1831           a specially reserved region and then later executed after
1832           a crash by kdump/kexec. The crash dump kernel must be compiled
1833           to a memory address not used by the main kernel or BIOS using
1834           PHYSICAL_START, or it must be built as a relocatable image
1835           (CONFIG_RELOCATABLE=y).
1836           For more details see Documentation/kdump/kdump.txt
1837 
1838 config KEXEC_JUMP
1839         bool "kexec jump"
1840         depends on KEXEC && HIBERNATION
1841         ---help---
1842           Jump between original kernel and kexeced kernel and invoke
1843           code in physical address mode via KEXEC
1844 
1845 config PHYSICAL_START
1846         hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1847         default "0x1000000"
1848         ---help---
1849           This gives the physical address where the kernel is loaded.
1850 
1851           If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1852           bzImage will decompress itself to above physical address and
1853           run from there. Otherwise, bzImage will run from the address where
1854           it has been loaded by the boot loader and will ignore above physical
1855           address.
1856 
1857           In normal kdump cases one does not have to set/change this option
1858           as now bzImage can be compiled as a completely relocatable image
1859           (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1860           address. This option is mainly useful for the folks who don't want
1861           to use a bzImage for capturing the crash dump and want to use a
1862           vmlinux instead. vmlinux is not relocatable hence a kernel needs
1863           to be specifically compiled to run from a specific memory area
1864           (normally a reserved region) and this option comes handy.
1865 
1866           So if you are using bzImage for capturing the crash dump,
1867           leave the value here unchanged to 0x1000000 and set
1868           CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
1869           for capturing the crash dump change this value to start of
1870           the reserved region.  In other words, it can be set based on
1871           the "X" value as specified in the "crashkernel=YM@XM"
1872           command line boot parameter passed to the panic-ed
1873           kernel. Please take a look at Documentation/kdump/kdump.txt
1874           for more details about crash dumps.
1875 
1876           Usage of bzImage for capturing the crash dump is recommended as
1877           one does not have to build two kernels. Same kernel can be used
1878           as production kernel and capture kernel. Above option should have
1879           gone away after relocatable bzImage support is introduced. But it
1880           is present because there are users out there who continue to use
1881           vmlinux for dump capture. This option should go away down the
1882           line.
1883 
1884           Don't change this unless you know what you are doing.
1885 
1886 config RELOCATABLE
1887         bool "Build a relocatable kernel"
1888         default y
1889         ---help---
1890           This builds a kernel image that retains relocation information
1891           so it can be loaded someplace besides the default 1MB.
1892           The relocations tend to make the kernel binary about 10% larger,
1893           but are discarded at runtime.
1894 
1895           One use is for the kexec on panic case where the recovery kernel
1896           must live at a different physical address than the primary
1897           kernel.
1898 
1899           Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1900           it has been loaded at and the compile time physical address
1901           (CONFIG_PHYSICAL_START) is used as the minimum location.
1902 
1903 config RANDOMIZE_BASE
1904         bool "Randomize the address of the kernel image"
1905         depends on RELOCATABLE
1906         default n
1907         ---help---
1908            Randomizes the physical and virtual address at which the
1909            kernel image is decompressed, as a security feature that
1910            deters exploit attempts relying on knowledge of the location
1911            of kernel internals.
1912 
1913            Entropy is generated using the RDRAND instruction if it is
1914            supported. If RDTSC is supported, it is used as well. If
1915            neither RDRAND nor RDTSC are supported, then randomness is
1916            read from the i8254 timer.
1917 
1918            The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1919            and aligned according to PHYSICAL_ALIGN. Since the kernel is
1920            built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1921            minimum of 2MiB, only 10 bits of entropy is theoretically
1922            possible. At best, due to page table layouts, 64-bit can use
1923            9 bits of entropy and 32-bit uses 8 bits.
1924 
1925            If unsure, say N.
1926 
1927 config RANDOMIZE_BASE_MAX_OFFSET
1928         hex "Maximum kASLR offset allowed" if EXPERT
1929         depends on RANDOMIZE_BASE
1930         range 0x0 0x20000000 if X86_32
1931         default "0x20000000" if X86_32
1932         range 0x0 0x40000000 if X86_64
1933         default "0x40000000" if X86_64
1934         ---help---
1935           The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1936           memory is used to determine the maximal offset in bytes that will
1937           be applied to the kernel when kernel Address Space Layout
1938           Randomization (kASLR) is active. This must be a multiple of
1939           PHYSICAL_ALIGN.
1940 
1941           On 32-bit this is limited to 512MiB by page table layouts. The
1942           default is 512MiB.
1943 
1944           On 64-bit this is limited by how the kernel fixmap page table is
1945           positioned, so this cannot be larger than 1GiB currently. Without
1946           RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1947           and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1948           modules area will shrink to compensate, up to the current maximum
1949           1GiB to 1GiB split. The default is 1GiB.
1950 
1951           If unsure, leave at the default value.
1952 
1953 # Relocation on x86 needs some additional build support
1954 config X86_NEED_RELOCS
1955         def_bool y
1956         depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1957 
1958 config PHYSICAL_ALIGN
1959         hex "Alignment value to which kernel should be aligned"
1960         default "0x200000"
1961         range 0x2000 0x1000000 if X86_32
1962         range 0x200000 0x1000000 if X86_64
1963         ---help---
1964           This value puts the alignment restrictions on physical address
1965           where kernel is loaded and run from. Kernel is compiled for an
1966           address which meets above alignment restriction.
1967 
1968           If bootloader loads the kernel at a non-aligned address and
1969           CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1970           address aligned to above value and run from there.
1971 
1972           If bootloader loads the kernel at a non-aligned address and
1973           CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1974           load address and decompress itself to the address it has been
1975           compiled for and run from there. The address for which kernel is
1976           compiled already meets above alignment restrictions. Hence the
1977           end result is that kernel runs from a physical address meeting
1978           above alignment restrictions.
1979 
1980           On 32-bit this value must be a multiple of 0x2000. On 64-bit
1981           this value must be a multiple of 0x200000.
1982 
1983           Don't change this unless you know what you are doing.
1984 
1985 config HOTPLUG_CPU
1986         bool "Support for hot-pluggable CPUs"
1987         depends on SMP
1988         ---help---
1989           Say Y here to allow turning CPUs off and on. CPUs can be
1990           controlled through /sys/devices/system/cpu.
1991           ( Note: power management support will enable this option
1992             automatically on SMP systems. )
1993           Say N if you want to disable CPU hotplug.
1994 
1995 config BOOTPARAM_HOTPLUG_CPU0
1996         bool "Set default setting of cpu0_hotpluggable"
1997         default n
1998         depends on HOTPLUG_CPU
1999         ---help---
2000           Set whether default state of cpu0_hotpluggable is on or off.
2001 
2002           Say Y here to enable CPU0 hotplug by default. If this switch
2003           is turned on, there is no need to give cpu0_hotplug kernel
2004           parameter and the CPU0 hotplug feature is enabled by default.
2005 
2006           Please note: there are two known CPU0 dependencies if you want
2007           to enable the CPU0 hotplug feature either by this switch or by
2008           cpu0_hotplug kernel parameter.
2009 
2010           First, resume from hibernate or suspend always starts from CPU0.
2011           So hibernate and suspend are prevented if CPU0 is offline.
2012 
2013           Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2014           offline if any interrupt can not migrate out of CPU0. There may
2015           be other CPU0 dependencies.
2016 
2017           Please make sure the dependencies are under your control before
2018           you enable this feature.
2019 
2020           Say N if you don't want to enable CPU0 hotplug feature by default.
2021           You still can enable the CPU0 hotplug feature at boot by kernel
2022           parameter cpu0_hotplug.
2023 
2024 config DEBUG_HOTPLUG_CPU0
2025         def_bool n
2026         prompt "Debug CPU0 hotplug"
2027         depends on HOTPLUG_CPU
2028         ---help---
2029           Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2030           soon as possible and boots up userspace with CPU0 offlined. User
2031           can online CPU0 back after boot time.
2032 
2033           To debug CPU0 hotplug, you need to enable CPU0 offline/online
2034           feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2035           compilation or giving cpu0_hotplug kernel parameter at boot.
2036 
2037           If unsure, say N.
2038 
2039 config COMPAT_VDSO
2040         def_bool n
2041         prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2042         depends on X86_32 || IA32_EMULATION
2043         ---help---
2044           Certain buggy versions of glibc will crash if they are
2045           presented with a 32-bit vDSO that is not mapped at the address
2046           indicated in its segment table.
2047 
2048           The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2049           and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2050           49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2051           the only released version with the bug, but OpenSUSE 9
2052           contains a buggy "glibc 2.3.2".
2053 
2054           The symptom of the bug is that everything crashes on startup, saying:
2055           dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2056 
2057           Saying Y here changes the default value of the vdso32 boot
2058           option from 1 to 0, which turns off the 32-bit vDSO entirely.
2059           This works around the glibc bug but hurts performance.
2060 
2061           If unsure, say N: if you are compiling your own kernel, you
2062           are unlikely to be using a buggy version of glibc.
2063 
2064 choice
2065         prompt "vsyscall table for legacy applications"
2066         depends on X86_64
2067         default LEGACY_VSYSCALL_EMULATE
2068         help
2069           Legacy user code that does not know how to find the vDSO expects
2070           to be able to issue three syscalls by calling fixed addresses in
2071           kernel space. Since this location is not randomized with ASLR,
2072           it can be used to assist security vulnerability exploitation.
2073 
2074           This setting can be changed at boot time via the kernel command
2075           line parameter vsyscall=[native|emulate|none].
2076 
2077           On a system with recent enough glibc (2.14 or newer) and no
2078           static binaries, you can say None without a performance penalty
2079           to improve security.
2080 
2081           If unsure, select "Emulate".
2082 
2083         config LEGACY_VSYSCALL_NATIVE
2084                 bool "Native"
2085                 help
2086                   Actual executable code is located in the fixed vsyscall
2087                   address mapping, implementing time() efficiently. Since
2088                   this makes the mapping executable, it can be used during
2089                   security vulnerability exploitation (traditionally as
2090                   ROP gadgets). This configuration is not recommended.
2091 
2092         config LEGACY_VSYSCALL_EMULATE
2093                 bool "Emulate"
2094                 help
2095                   The kernel traps and emulates calls into the fixed
2096                   vsyscall address mapping. This makes the mapping
2097                   non-executable, but it still contains known contents,
2098                   which could be used in certain rare security vulnerability
2099                   exploits. This configuration is recommended when userspace
2100                   still uses the vsyscall area.
2101 
2102         config LEGACY_VSYSCALL_NONE
2103                 bool "None"
2104                 help
2105                   There will be no vsyscall mapping at all. This will
2106                   eliminate any risk of ASLR bypass due to the vsyscall
2107                   fixed address mapping. Attempts to use the vsyscalls
2108                   will be reported to dmesg, so that either old or
2109                   malicious userspace programs can be identified.
2110 
2111 endchoice
2112 
2113 config CMDLINE_BOOL
2114         bool "Built-in kernel command line"
2115         ---help---
2116           Allow for specifying boot arguments to the kernel at
2117           build time.  On some systems (e.g. embedded ones), it is
2118           necessary or convenient to provide some or all of the
2119           kernel boot arguments with the kernel itself (that is,
2120           to not rely on the boot loader to provide them.)
2121 
2122           To compile command line arguments into the kernel,
2123           set this option to 'Y', then fill in the
2124           boot arguments in CONFIG_CMDLINE.
2125 
2126           Systems with fully functional boot loaders (i.e. non-embedded)
2127           should leave this option set to 'N'.
2128 
2129 config CMDLINE
2130         string "Built-in kernel command string"
2131         depends on CMDLINE_BOOL
2132         default ""
2133         ---help---
2134           Enter arguments here that should be compiled into the kernel
2135           image and used at boot time.  If the boot loader provides a
2136           command line at boot time, it is appended to this string to
2137           form the full kernel command line, when the system boots.
2138 
2139           However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2140           change this behavior.
2141 
2142           In most cases, the command line (whether built-in or provided
2143           by the boot loader) should specify the device for the root
2144           file system.
2145 
2146 config CMDLINE_OVERRIDE
2147         bool "Built-in command line overrides boot loader arguments"
2148         depends on CMDLINE_BOOL
2149         ---help---
2150           Set this option to 'Y' to have the kernel ignore the boot loader
2151           command line, and use ONLY the built-in command line.
2152 
2153           This is used to work around broken boot loaders.  This should
2154           be set to 'N' under normal conditions.
2155 
2156 config MODIFY_LDT_SYSCALL
2157         bool "Enable the LDT (local descriptor table)" if EXPERT
2158         default y
2159         ---help---
2160           Linux can allow user programs to install a per-process x86
2161           Local Descriptor Table (LDT) using the modify_ldt(2) system
2162           call.  This is required to run 16-bit or segmented code such as
2163           DOSEMU or some Wine programs.  It is also used by some very old
2164           threading libraries.
2165 
2166           Enabling this feature adds a small amount of overhead to
2167           context switches and increases the low-level kernel attack
2168           surface.  Disabling it removes the modify_ldt(2) system call.
2169 
2170           Saying 'N' here may make sense for embedded or server kernels.
2171 
2172 source "kernel/livepatch/Kconfig"
2173 
2174 endmenu
2175 
2176 config ARCH_ENABLE_MEMORY_HOTPLUG
2177         def_bool y
2178         depends on X86_64 || (X86_32 && HIGHMEM)
2179 
2180 config ARCH_ENABLE_MEMORY_HOTREMOVE
2181         def_bool y
2182         depends on MEMORY_HOTPLUG
2183 
2184 config USE_PERCPU_NUMA_NODE_ID
2185         def_bool y
2186         depends on NUMA
2187 
2188 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2189         def_bool y
2190         depends on X86_64 || X86_PAE
2191 
2192 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2193         def_bool y
2194         depends on X86_64 && HUGETLB_PAGE && MIGRATION
2195 
2196 menu "Power management and ACPI options"
2197 
2198 config ARCH_HIBERNATION_HEADER
2199         def_bool y
2200         depends on X86_64 && HIBERNATION
2201 
2202 source "kernel/power/Kconfig"
2203 
2204 source "drivers/acpi/Kconfig"
2205 
2206 source "drivers/sfi/Kconfig"
2207 
2208 config X86_APM_BOOT
2209         def_bool y
2210         depends on APM
2211 
2212 menuconfig APM
2213         tristate "APM (Advanced Power Management) BIOS support"
2214         depends on X86_32 && PM_SLEEP
2215         ---help---
2216           APM is a BIOS specification for saving power using several different
2217           techniques. This is mostly useful for battery powered laptops with
2218           APM compliant BIOSes. If you say Y here, the system time will be
2219           reset after a RESUME operation, the /proc/apm device will provide
2220           battery status information, and user-space programs will receive
2221           notification of APM "events" (e.g. battery status change).
2222 
2223           If you select "Y" here, you can disable actual use of the APM
2224           BIOS by passing the "apm=off" option to the kernel at boot time.
2225 
2226           Note that the APM support is almost completely disabled for
2227           machines with more than one CPU.
2228 
2229           In order to use APM, you will need supporting software. For location
2230           and more information, read <file:Documentation/power/apm-acpi.txt>
2231           and the Battery Powered Linux mini-HOWTO, available from
2232           <http://www.tldp.org/docs.html#howto>.
2233 
2234           This driver does not spin down disk drives (see the hdparm(8)
2235           manpage ("man 8 hdparm") for that), and it doesn't turn off
2236           VESA-compliant "green" monitors.
2237 
2238           This driver does not support the TI 4000M TravelMate and the ACER
2239           486/DX4/75 because they don't have compliant BIOSes. Many "green"
2240           desktop machines also don't have compliant BIOSes, and this driver
2241           may cause those machines to panic during the boot phase.
2242 
2243           Generally, if you don't have a battery in your machine, there isn't
2244           much point in using this driver and you should say N. If you get
2245           random kernel OOPSes or reboots that don't seem to be related to
2246           anything, try disabling/enabling this option (or disabling/enabling
2247           APM in your BIOS).
2248 
2249           Some other things you should try when experiencing seemingly random,
2250           "weird" problems:
2251 
2252           1) make sure that you have enough swap space and that it is
2253           enabled.
2254           2) pass the "no-hlt" option to the kernel
2255           3) switch on floating point emulation in the kernel and pass
2256           the "no387" option to the kernel
2257           4) pass the "floppy=nodma" option to the kernel
2258           5) pass the "mem=4M" option to the kernel (thereby disabling
2259           all but the first 4 MB of RAM)
2260           6) make sure that the CPU is not over clocked.
2261           7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2262           8) disable the cache from your BIOS settings
2263           9) install a fan for the video card or exchange video RAM
2264           10) install a better fan for the CPU
2265           11) exchange RAM chips
2266           12) exchange the motherboard.
2267 
2268           To compile this driver as a module, choose M here: the
2269           module will be called apm.
2270 
2271 if APM
2272 
2273 config APM_IGNORE_USER_SUSPEND
2274         bool "Ignore USER SUSPEND"
2275         ---help---
2276           This option will ignore USER SUSPEND requests. On machines with a
2277           compliant APM BIOS, you want to say N. However, on the NEC Versa M
2278           series notebooks, it is necessary to say Y because of a BIOS bug.
2279 
2280 config APM_DO_ENABLE
2281         bool "Enable PM at boot time"
2282         ---help---
2283           Enable APM features at boot time. From page 36 of the APM BIOS
2284           specification: "When disabled, the APM BIOS does not automatically
2285           power manage devices, enter the Standby State, enter the Suspend
2286           State, or take power saving steps in response to CPU Idle calls."
2287           This driver will make CPU Idle calls when Linux is idle (unless this
2288           feature is turned off -- see "Do CPU IDLE calls", below). This
2289           should always save battery power, but more complicated APM features
2290           will be dependent on your BIOS implementation. You may need to turn
2291           this option off if your computer hangs at boot time when using APM
2292           support, or if it beeps continuously instead of suspending. Turn
2293           this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2294           T400CDT. This is off by default since most machines do fine without
2295           this feature.
2296 
2297 config APM_CPU_IDLE
2298         depends on CPU_IDLE
2299         bool "Make CPU Idle calls when idle"
2300         ---help---
2301           Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2302           On some machines, this can activate improved power savings, such as
2303           a slowed CPU clock rate, when the machine is idle. These idle calls
2304           are made after the idle loop has run for some length of time (e.g.,
2305           333 mS). On some machines, this will cause a hang at boot time or
2306           whenever the CPU becomes idle. (On machines with more than one CPU,
2307           this option does nothing.)
2308 
2309 config APM_DISPLAY_BLANK
2310         bool "Enable console blanking using APM"
2311         ---help---
2312           Enable console blanking using the APM. Some laptops can use this to
2313           turn off the LCD backlight when the screen blanker of the Linux
2314           virtual console blanks the screen. Note that this is only used by
2315           the virtual console screen blanker, and won't turn off the backlight
2316           when using the X Window system. This also doesn't have anything to
2317           do with your VESA-compliant power-saving monitor. Further, this
2318           option doesn't work for all laptops -- it might not turn off your
2319           backlight at all, or it might print a lot of errors to the console,
2320           especially if you are using gpm.
2321 
2322 config APM_ALLOW_INTS
2323         bool "Allow interrupts during APM BIOS calls"
2324         ---help---
2325           Normally we disable external interrupts while we are making calls to
2326           the APM BIOS as a measure to lessen the effects of a badly behaving
2327           BIOS implementation.  The BIOS should reenable interrupts if it
2328           needs to.  Unfortunately, some BIOSes do not -- especially those in
2329           many of the newer IBM Thinkpads.  If you experience hangs when you
2330           suspend, try setting this to Y.  Otherwise, say N.
2331 
2332 endif # APM
2333 
2334 source "drivers/cpufreq/Kconfig"
2335 
2336 source "drivers/cpuidle/Kconfig"
2337 
2338 source "drivers/idle/Kconfig"
2339 
2340 endmenu
2341 
2342 
2343 menu "Bus options (PCI etc.)"
2344 
2345 config PCI
2346         bool "PCI support"
2347         default y
2348         ---help---
2349           Find out whether you have a PCI motherboard. PCI is the name of a
2350           bus system, i.e. the way the CPU talks to the other stuff inside
2351           your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2352           VESA. If you have PCI, say Y, otherwise N.
2353 
2354 choice
2355         prompt "PCI access mode"
2356         depends on X86_32 && PCI
2357         default PCI_GOANY
2358         ---help---
2359           On PCI systems, the BIOS can be used to detect the PCI devices and
2360           determine their configuration. However, some old PCI motherboards
2361           have BIOS bugs and may crash if this is done. Also, some embedded
2362           PCI-based systems don't have any BIOS at all. Linux can also try to
2363           detect the PCI hardware directly without using the BIOS.
2364 
2365           With this option, you can specify how Linux should detect the
2366           PCI devices. If you choose "BIOS", the BIOS will be used,
2367           if you choose "Direct", the BIOS won't be used, and if you
2368           choose "MMConfig", then PCI Express MMCONFIG will be used.
2369           If you choose "Any", the kernel will try MMCONFIG, then the
2370           direct access method and falls back to the BIOS if that doesn't
2371           work. If unsure, go with the default, which is "Any".
2372 
2373 config PCI_GOBIOS
2374         bool "BIOS"
2375 
2376 config PCI_GOMMCONFIG
2377         bool "MMConfig"
2378 
2379 config PCI_GODIRECT
2380         bool "Direct"
2381 
2382 config PCI_GOOLPC
2383         bool "OLPC XO-1"
2384         depends on OLPC
2385 
2386 config PCI_GOANY
2387         bool "Any"
2388 
2389 endchoice
2390 
2391 config PCI_BIOS
2392         def_bool y
2393         depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2394 
2395 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2396 config PCI_DIRECT
2397         def_bool y
2398         depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2399 
2400 config PCI_MMCONFIG
2401         def_bool y
2402         depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2403 
2404 config PCI_OLPC
2405         def_bool y
2406         depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2407 
2408 config PCI_XEN
2409         def_bool y
2410         depends on PCI && XEN
2411         select SWIOTLB_XEN
2412 
2413 config PCI_DOMAINS
2414         def_bool y
2415         depends on PCI
2416 
2417 config PCI_MMCONFIG
2418         bool "Support mmconfig PCI config space access"
2419         depends on X86_64 && PCI && ACPI
2420 
2421 config PCI_CNB20LE_QUIRK
2422         bool "Read CNB20LE Host Bridge Windows" if EXPERT
2423         depends on PCI
2424         help
2425           Read the PCI windows out of the CNB20LE host bridge. This allows
2426           PCI hotplug to work on systems with the CNB20LE chipset which do
2427           not have ACPI.
2428 
2429           There's no public spec for this chipset, and this functionality
2430           is known to be incomplete.
2431 
2432           You should say N unless you know you need this.
2433 
2434 source "drivers/pci/pcie/Kconfig"
2435 
2436 source "drivers/pci/Kconfig"
2437 
2438 # x86_64 have no ISA slots, but can have ISA-style DMA.
2439 config ISA_DMA_API
2440         bool "ISA-style DMA support" if (X86_64 && EXPERT)
2441         default y
2442         help
2443           Enables ISA-style DMA support for devices requiring such controllers.
2444           If unsure, say Y.
2445 
2446 if X86_32
2447 
2448 config ISA
2449         bool "ISA support"
2450         ---help---
2451           Find out whether you have ISA slots on your motherboard.  ISA is the
2452           name of a bus system, i.e. the way the CPU talks to the other stuff
2453           inside your box.  Other bus systems are PCI, EISA, MicroChannel
2454           (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2455           newer boards don't support it.  If you have ISA, say Y, otherwise N.
2456 
2457 config EISA
2458         bool "EISA support"
2459         depends on ISA
2460         ---help---
2461           The Extended Industry Standard Architecture (EISA) bus was
2462           developed as an open alternative to the IBM MicroChannel bus.
2463 
2464           The EISA bus provided some of the features of the IBM MicroChannel
2465           bus while maintaining backward compatibility with cards made for
2466           the older ISA bus.  The EISA bus saw limited use between 1988 and
2467           1995 when it was made obsolete by the PCI bus.
2468 
2469           Say Y here if you are building a kernel for an EISA-based machine.
2470 
2471           Otherwise, say N.
2472 
2473 source "drivers/eisa/Kconfig"
2474 
2475 config SCx200
2476         tristate "NatSemi SCx200 support"
2477         ---help---
2478           This provides basic support for National Semiconductor's
2479           (now AMD's) Geode processors.  The driver probes for the
2480           PCI-IDs of several on-chip devices, so its a good dependency
2481           for other scx200_* drivers.
2482 
2483           If compiled as a module, the driver is named scx200.
2484 
2485 config SCx200HR_TIMER
2486         tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2487         depends on SCx200
2488         default y
2489         ---help---
2490           This driver provides a clocksource built upon the on-chip
2491           27MHz high-resolution timer.  Its also a workaround for
2492           NSC Geode SC-1100's buggy TSC, which loses time when the
2493           processor goes idle (as is done by the scheduler).  The
2494           other workaround is idle=poll boot option.
2495 
2496 config OLPC
2497         bool "One Laptop Per Child support"
2498         depends on !X86_PAE
2499         select GPIOLIB
2500         select OF
2501         select OF_PROMTREE
2502         select IRQ_DOMAIN
2503         ---help---
2504           Add support for detecting the unique features of the OLPC
2505           XO hardware.
2506 
2507 config OLPC_XO1_PM
2508         bool "OLPC XO-1 Power Management"
2509         depends on OLPC && MFD_CS5535 && PM_SLEEP
2510         select MFD_CORE
2511         ---help---
2512           Add support for poweroff and suspend of the OLPC XO-1 laptop.
2513 
2514 config OLPC_XO1_RTC
2515         bool "OLPC XO-1 Real Time Clock"
2516         depends on OLPC_XO1_PM && RTC_DRV_CMOS
2517         ---help---
2518           Add support for the XO-1 real time clock, which can be used as a
2519           programmable wakeup source.
2520 
2521 config OLPC_XO1_SCI
2522         bool "OLPC XO-1 SCI extras"
2523         depends on OLPC && OLPC_XO1_PM
2524         depends on INPUT=y
2525         select POWER_SUPPLY
2526         select GPIO_CS5535
2527         select MFD_CORE
2528         ---help---
2529           Add support for SCI-based features of the OLPC XO-1 laptop:
2530            - EC-driven system wakeups
2531            - Power button
2532            - Ebook switch
2533            - Lid switch
2534            - AC adapter status updates
2535            - Battery status updates
2536 
2537 config OLPC_XO15_SCI
2538         bool "OLPC XO-1.5 SCI extras"
2539         depends on OLPC && ACPI
2540         select POWER_SUPPLY
2541         ---help---
2542           Add support for SCI-based features of the OLPC XO-1.5 laptop:
2543            - EC-driven system wakeups
2544            - AC adapter status updates
2545            - Battery status updates
2546 
2547 config ALIX
2548         bool "PCEngines ALIX System Support (LED setup)"
2549         select GPIOLIB
2550         ---help---
2551           This option enables system support for the PCEngines ALIX.
2552           At present this just sets up LEDs for GPIO control on
2553           ALIX2/3/6 boards.  However, other system specific setup should
2554           get added here.
2555 
2556           Note: You must still enable the drivers for GPIO and LED support
2557           (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2558 
2559           Note: You have to set alix.force=1 for boards with Award BIOS.
2560 
2561 config NET5501
2562         bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2563         select GPIOLIB
2564         ---help---
2565           This option enables system support for the Soekris Engineering net5501.
2566 
2567 config GEOS
2568         bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2569         select GPIOLIB
2570         depends on DMI
2571         ---help---
2572           This option enables system support for the Traverse Technologies GEOS.
2573 
2574 config TS5500
2575         bool "Technologic Systems TS-5500 platform support"
2576         depends on MELAN
2577         select CHECK_SIGNATURE
2578         select NEW_LEDS
2579         select LEDS_CLASS
2580         ---help---
2581           This option enables system support for the Technologic Systems TS-5500.
2582 
2583 endif # X86_32
2584 
2585 config AMD_NB
2586         def_bool y
2587         depends on CPU_SUP_AMD && PCI
2588 
2589 source "drivers/pcmcia/Kconfig"
2590 
2591 source "drivers/pci/hotplug/Kconfig"
2592 
2593 config RAPIDIO
2594         tristate "RapidIO support"
2595         depends on PCI
2596         default n
2597         help
2598           If enabled this option will include drivers and the core
2599           infrastructure code to support RapidIO interconnect devices.
2600 
2601 source "drivers/rapidio/Kconfig"
2602 
2603 config X86_SYSFB
2604         bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2605         help
2606           Firmwares often provide initial graphics framebuffers so the BIOS,
2607           bootloader or kernel can show basic video-output during boot for
2608           user-guidance and debugging. Historically, x86 used the VESA BIOS
2609           Extensions and EFI-framebuffers for this, which are mostly limited
2610           to x86.
2611           This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2612           framebuffers so the new generic system-framebuffer drivers can be
2613           used on x86. If the framebuffer is not compatible with the generic
2614           modes, it is adverticed as fallback platform framebuffer so legacy
2615           drivers like efifb, vesafb and uvesafb can pick it up.
2616           If this option is not selected, all system framebuffers are always
2617           marked as fallback platform framebuffers as usual.
2618 
2619           Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2620           not be able to pick up generic system framebuffers if this option
2621           is selected. You are highly encouraged to enable simplefb as
2622           replacement if you select this option. simplefb can correctly deal
2623           with generic system framebuffers. But you should still keep vesafb
2624           and others enabled as fallback if a system framebuffer is
2625           incompatible with simplefb.
2626 
2627           If unsure, say Y.
2628 
2629 endmenu
2630 
2631 
2632 menu "Executable file formats / Emulations"
2633 
2634 source "fs/Kconfig.binfmt"
2635 
2636 config IA32_EMULATION
2637         bool "IA32 Emulation"
2638         depends on X86_64
2639         select BINFMT_ELF
2640         select COMPAT_BINFMT_ELF
2641         select ARCH_WANT_OLD_COMPAT_IPC
2642         ---help---
2643           Include code to run legacy 32-bit programs under a
2644           64-bit kernel. You should likely turn this on, unless you're
2645           100% sure that you don't have any 32-bit programs left.
2646 
2647 config IA32_AOUT
2648         tristate "IA32 a.out support"
2649         depends on IA32_EMULATION
2650         ---help---
2651           Support old a.out binaries in the 32bit emulation.
2652 
2653 config X86_X32
2654         bool "x32 ABI for 64-bit mode"
2655         depends on X86_64
2656         ---help---
2657           Include code to run binaries for the x32 native 32-bit ABI
2658           for 64-bit processors.  An x32 process gets access to the
2659           full 64-bit register file and wide data path while leaving
2660           pointers at 32 bits for smaller memory footprint.
2661 
2662           You will need a recent binutils (2.22 or later) with
2663           elf32_x86_64 support enabled to compile a kernel with this
2664           option set.
2665 
2666 config COMPAT
2667         def_bool y
2668         depends on IA32_EMULATION || X86_X32
2669 
2670 if COMPAT
2671 config COMPAT_FOR_U64_ALIGNMENT
2672         def_bool y
2673 
2674 config SYSVIPC_COMPAT
2675         def_bool y
2676         depends on SYSVIPC
2677 
2678 config KEYS_COMPAT
2679         def_bool y
2680         depends on KEYS
2681 endif
2682 
2683 endmenu
2684 
2685 
2686 config HAVE_ATOMIC_IOMAP
2687         def_bool y
2688         depends on X86_32
2689 
2690 config X86_DEV_DMA_OPS
2691         bool
2692         depends on X86_64 || STA2X11
2693 
2694 config X86_DMA_REMAP
2695         bool
2696         depends on STA2X11
2697 
2698 config PMC_ATOM
2699         def_bool y
2700         depends on PCI
2701 
2702 config VMD
2703         depends on PCI_MSI
2704         tristate "Volume Management Device Driver"
2705         default N
2706         ---help---
2707           Adds support for the Intel Volume Management Device (VMD). VMD is a
2708           secondary PCI host bridge that allows PCI Express root ports,
2709           and devices attached to them, to be removed from the default
2710           PCI domain and placed within the VMD domain. This provides
2711           more bus resources than are otherwise possible with a
2712           single domain. If you know your system provides one of these and
2713           has devices attached to it, say Y; if you are not sure, say N.
2714 
2715 source "net/Kconfig"
2716 
2717 source "drivers/Kconfig"
2718 
2719 source "drivers/firmware/Kconfig"
2720 
2721 source "fs/Kconfig"
2722 
2723 source "arch/x86/Kconfig.debug"
2724 
2725 source "security/Kconfig"
2726 
2727 source "crypto/Kconfig"
2728 
2729 source "arch/x86/kvm/Kconfig"
2730 
2731 source "lib/Kconfig"

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