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

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