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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_ACPI_TABLE_UPGRADE if ACPI
 26         select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 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 BUILDTIME_EXTABLE_SORT
 53         select CLKEVT_I8253
 54         select CLKSRC_I8253                     if X86_32
 55         select CLOCKSOURCE_VALIDATE_LAST_CYCLE
 56         select CLOCKSOURCE_WATCHDOG
 57         select CLONE_BACKWARDS                  if X86_32
 58         select COMPAT_OLD_SIGACTION             if IA32_EMULATION
 59         select DCACHE_WORD_ACCESS
 60         select EDAC_ATOMIC_SCRUB
 61         select EDAC_SUPPORT
 62         select GENERIC_CLOCKEVENTS
 63         select GENERIC_CLOCKEVENTS_BROADCAST    if X86_64 || (X86_32 && X86_LOCAL_APIC)
 64         select GENERIC_CLOCKEVENTS_MIN_ADJUST
 65         select GENERIC_CMOS_UPDATE
 66         select GENERIC_CPU_AUTOPROBE
 67         select GENERIC_EARLY_IOREMAP
 68         select GENERIC_FIND_FIRST_BIT
 69         select GENERIC_IOMAP
 70         select GENERIC_IRQ_PROBE
 71         select GENERIC_IRQ_SHOW
 72         select GENERIC_PENDING_IRQ              if SMP
 73         select GENERIC_SMP_IDLE_THREAD
 74         select GENERIC_STRNCPY_FROM_USER
 75         select GENERIC_STRNLEN_USER
 76         select GENERIC_TIME_VSYSCALL
 77         select HAVE_ACPI_APEI                   if ACPI
 78         select HAVE_ACPI_APEI_NMI               if ACPI
 79         select HAVE_ALIGNED_STRUCT_PAGE         if SLUB
 80         select HAVE_AOUT                        if X86_32
 81         select HAVE_ARCH_AUDITSYSCALL
 82         select HAVE_ARCH_HARDENED_USERCOPY
 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_ARCH_WITHIN_STACK_FRAMES
 95         select HAVE_EBPF_JIT                    if X86_64
 96         select HAVE_CC_STACKPROTECTOR
 97         select HAVE_CMPXCHG_DOUBLE
 98         select HAVE_CMPXCHG_LOCAL
 99         select HAVE_CONTEXT_TRACKING            if X86_64
100         select HAVE_COPY_THREAD_TLS
101         select HAVE_C_RECORDMCOUNT
102         select HAVE_DEBUG_KMEMLEAK
103         select HAVE_DEBUG_STACKOVERFLOW
104         select HAVE_DMA_API_DEBUG
105         select HAVE_DMA_CONTIGUOUS
106         select HAVE_DYNAMIC_FTRACE
107         select HAVE_DYNAMIC_FTRACE_WITH_REGS
108         select HAVE_EFFICIENT_UNALIGNED_ACCESS
109         select HAVE_EXIT_THREAD
110         select HAVE_FENTRY                      if X86_64
111         select HAVE_FTRACE_MCOUNT_RECORD
112         select HAVE_FUNCTION_GRAPH_FP_TEST
113         select HAVE_FUNCTION_GRAPH_TRACER
114         select HAVE_FUNCTION_TRACER
115         select HAVE_GCC_PLUGINS
116         select HAVE_GENERIC_DMA_COHERENT        if X86_32
117         select HAVE_HW_BREAKPOINT
118         select HAVE_IDE
119         select HAVE_IOREMAP_PROT
120         select HAVE_IRQ_EXIT_ON_IRQ_STACK       if X86_64
121         select HAVE_IRQ_TIME_ACCOUNTING
122         select HAVE_KERNEL_BZIP2
123         select HAVE_KERNEL_GZIP
124         select HAVE_KERNEL_LZ4
125         select HAVE_KERNEL_LZMA
126         select HAVE_KERNEL_LZO
127         select HAVE_KERNEL_XZ
128         select HAVE_KPROBES
129         select HAVE_KPROBES_ON_FTRACE
130         select HAVE_KRETPROBES
131         select HAVE_KVM
132         select HAVE_LIVEPATCH                   if X86_64
133         select HAVE_MEMBLOCK
134         select HAVE_MEMBLOCK_NODE_MAP
135         select HAVE_MIXED_BREAKPOINTS_REGS
136         select HAVE_NMI
137         select HAVE_OPROFILE
138         select HAVE_OPTPROBES
139         select HAVE_PCSPKR_PLATFORM
140         select HAVE_PERF_EVENTS
141         select HAVE_PERF_EVENTS_NMI
142         select HAVE_PERF_REGS
143         select HAVE_PERF_USER_STACK_DUMP
144         select HAVE_REGS_AND_STACK_ACCESS_API
145         select HAVE_SYSCALL_TRACEPOINTS
146         select HAVE_UID16                       if X86_32 || IA32_EMULATION
147         select HAVE_UNSTABLE_SCHED_CLOCK
148         select HAVE_USER_RETURN_NOTIFIER
149         select IRQ_FORCED_THREADING
150         select MODULES_USE_ELF_RELA             if X86_64
151         select MODULES_USE_ELF_REL              if X86_32
152         select OLD_SIGACTION                    if X86_32
153         select OLD_SIGSUSPEND3                  if X86_32 || IA32_EMULATION
154         select PERF_EVENTS
155         select RTC_LIB
156         select RTC_MC146818_LIB
157         select SPARSE_IRQ
158         select SRCU
159         select SYSCTL_EXCEPTION_TRACE
160         select USER_STACKTRACE_SUPPORT
161         select VIRT_TO_BUS
162         select X86_DEV_DMA_OPS                  if X86_64
163         select X86_FEATURE_NAMES                if PROC_FS
164         select HAVE_STACK_VALIDATION            if X86_64
165         select ARCH_USES_HIGH_VMA_FLAGS         if X86_INTEL_MEMORY_PROTECTION_KEYS
166         select ARCH_HAS_PKEYS                   if X86_INTEL_MEMORY_PROTECTION_KEYS
167 
168 config INSTRUCTION_DECODER
169         def_bool y
170         depends on KPROBES || PERF_EVENTS || UPROBES
171 
172 config OUTPUT_FORMAT
173         string
174         default "elf32-i386" if X86_32
175         default "elf64-x86-64" if X86_64
176 
177 config ARCH_DEFCONFIG
178         string
179         default "arch/x86/configs/i386_defconfig" if X86_32
180         default "arch/x86/configs/x86_64_defconfig" if X86_64
181 
182 config LOCKDEP_SUPPORT
183         def_bool y
184 
185 config STACKTRACE_SUPPORT
186         def_bool y
187 
188 config MMU
189         def_bool y
190 
191 config ARCH_MMAP_RND_BITS_MIN
192         default 28 if 64BIT
193         default 8
194 
195 config ARCH_MMAP_RND_BITS_MAX
196         default 32 if 64BIT
197         default 16
198 
199 config ARCH_MMAP_RND_COMPAT_BITS_MIN
200         default 8
201 
202 config ARCH_MMAP_RND_COMPAT_BITS_MAX
203         default 16
204 
205 config SBUS
206         bool
207 
208 config NEED_DMA_MAP_STATE
209         def_bool y
210         depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
211 
212 config NEED_SG_DMA_LENGTH
213         def_bool y
214 
215 config GENERIC_ISA_DMA
216         def_bool y
217         depends on ISA_DMA_API
218 
219 config GENERIC_BUG
220         def_bool y
221         depends on BUG
222         select GENERIC_BUG_RELATIVE_POINTERS if X86_64
223 
224 config GENERIC_BUG_RELATIVE_POINTERS
225         bool
226 
227 config GENERIC_HWEIGHT
228         def_bool y
229 
230 config ARCH_MAY_HAVE_PC_FDC
231         def_bool y
232         depends on ISA_DMA_API
233 
234 config RWSEM_XCHGADD_ALGORITHM
235         def_bool y
236 
237 config GENERIC_CALIBRATE_DELAY
238         def_bool y
239 
240 config ARCH_HAS_CPU_RELAX
241         def_bool y
242 
243 config ARCH_HAS_CACHE_LINE_SIZE
244         def_bool y
245 
246 config HAVE_SETUP_PER_CPU_AREA
247         def_bool y
248 
249 config NEED_PER_CPU_EMBED_FIRST_CHUNK
250         def_bool y
251 
252 config NEED_PER_CPU_PAGE_FIRST_CHUNK
253         def_bool y
254 
255 config ARCH_HIBERNATION_POSSIBLE
256         def_bool y
257 
258 config ARCH_SUSPEND_POSSIBLE
259         def_bool y
260 
261 config ARCH_WANT_HUGE_PMD_SHARE
262         def_bool y
263 
264 config ARCH_WANT_GENERAL_HUGETLB
265         def_bool y
266 
267 config ZONE_DMA32
268         def_bool y if X86_64
269 
270 config AUDIT_ARCH
271         def_bool y if X86_64
272 
273 config ARCH_SUPPORTS_OPTIMIZED_INLINING
274         def_bool y
275 
276 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
277         def_bool y
278 
279 config KASAN_SHADOW_OFFSET
280         hex
281         depends on KASAN
282         default 0xdffffc0000000000
283 
284 config HAVE_INTEL_TXT
285         def_bool y
286         depends on INTEL_IOMMU && ACPI
287 
288 config X86_32_SMP
289         def_bool y
290         depends on X86_32 && SMP
291 
292 config X86_64_SMP
293         def_bool y
294         depends on X86_64 && SMP
295 
296 config X86_32_LAZY_GS
297         def_bool y
298         depends on X86_32 && !CC_STACKPROTECTOR
299 
300 config ARCH_SUPPORTS_UPROBES
301         def_bool y
302 
303 config FIX_EARLYCON_MEM
304         def_bool y
305 
306 config DEBUG_RODATA
307         def_bool y
308 
309 config PGTABLE_LEVELS
310         int
311         default 4 if X86_64
312         default 3 if X86_PAE
313         default 2
314 
315 source "init/Kconfig"
316 source "kernel/Kconfig.freezer"
317 
318 menu "Processor type and features"
319 
320 config ZONE_DMA
321         bool "DMA memory allocation support" if EXPERT
322         default y
323         help
324           DMA memory allocation support allows devices with less than 32-bit
325           addressing to allocate within the first 16MB of address space.
326           Disable if no such devices will be used.
327 
328           If unsure, say Y.
329 
330 config SMP
331         bool "Symmetric multi-processing support"
332         ---help---
333           This enables support for systems with more than one CPU. If you have
334           a system with only one CPU, say N. If you have a system with more
335           than one CPU, say Y.
336 
337           If you say N here, the kernel will run on uni- and multiprocessor
338           machines, but will use only one CPU of a multiprocessor machine. If
339           you say Y here, the kernel will run on many, but not all,
340           uniprocessor machines. On a uniprocessor machine, the kernel
341           will run faster if you say N here.
342 
343           Note that if you say Y here and choose architecture "586" or
344           "Pentium" under "Processor family", the kernel will not work on 486
345           architectures. Similarly, multiprocessor kernels for the "PPro"
346           architecture may not work on all Pentium based boards.
347 
348           People using multiprocessor machines who say Y here should also say
349           Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
350           Management" code will be disabled if you say Y here.
351 
352           See also <file:Documentation/x86/i386/IO-APIC.txt>,
353           <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
354           <http://www.tldp.org/docs.html#howto>.
355 
356           If you don't know what to do here, say N.
357 
358 config X86_FEATURE_NAMES
359         bool "Processor feature human-readable names" if EMBEDDED
360         default y
361         ---help---
362           This option compiles in a table of x86 feature bits and corresponding
363           names.  This is required to support /proc/cpuinfo and a few kernel
364           messages.  You can disable this to save space, at the expense of
365           making those few kernel messages show numeric feature bits instead.
366 
367           If in doubt, say Y.
368 
369 config X86_FAST_FEATURE_TESTS
370         bool "Fast CPU feature tests" if EMBEDDED
371         default y
372         ---help---
373           Some fast-paths in the kernel depend on the capabilities of the CPU.
374           Say Y here for the kernel to patch in the appropriate code at runtime
375           based on the capabilities of the CPU. The infrastructure for patching
376           code at runtime takes up some additional space; space-constrained
377           embedded systems may wish to say N here to produce smaller, slightly
378           slower code.
379 
380 config X86_X2APIC
381         bool "Support x2apic"
382         depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
383         ---help---
384           This enables x2apic support on CPUs that have this feature.
385 
386           This allows 32-bit apic IDs (so it can support very large systems),
387           and accesses the local apic via MSRs not via mmio.
388 
389           If you don't know what to do here, say N.
390 
391 config X86_MPPARSE
392         bool "Enable MPS table" if ACPI || SFI
393         default y
394         depends on X86_LOCAL_APIC
395         ---help---
396           For old smp systems that do not have proper acpi support. Newer systems
397           (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
398 
399 config X86_BIGSMP
400         bool "Support for big SMP systems with more than 8 CPUs"
401         depends on X86_32 && SMP
402         ---help---
403           This option is needed for the systems that have more than 8 CPUs
404 
405 config GOLDFISH
406        def_bool y
407        depends on X86_GOLDFISH
408 
409 if X86_32
410 config X86_EXTENDED_PLATFORM
411         bool "Support for extended (non-PC) x86 platforms"
412         default y
413         ---help---
414           If you disable this option then the kernel will only support
415           standard PC platforms. (which covers the vast majority of
416           systems out there.)
417 
418           If you enable this option then you'll be able to select support
419           for the following (non-PC) 32 bit x86 platforms:
420                 Goldfish (Android emulator)
421                 AMD Elan
422                 RDC R-321x SoC
423                 SGI 320/540 (Visual Workstation)
424                 STA2X11-based (e.g. Northville)
425                 Moorestown MID devices
426 
427           If you have one of these systems, or if you want to build a
428           generic distribution kernel, say Y here - otherwise say N.
429 endif
430 
431 if X86_64
432 config X86_EXTENDED_PLATFORM
433         bool "Support for extended (non-PC) x86 platforms"
434         default y
435         ---help---
436           If you disable this option then the kernel will only support
437           standard PC platforms. (which covers the vast majority of
438           systems out there.)
439 
440           If you enable this option then you'll be able to select support
441           for the following (non-PC) 64 bit x86 platforms:
442                 Numascale NumaChip
443                 ScaleMP vSMP
444                 SGI Ultraviolet
445 
446           If you have one of these systems, or if you want to build a
447           generic distribution kernel, say Y here - otherwise say N.
448 endif
449 # This is an alphabetically sorted list of 64 bit extended platforms
450 # Please maintain the alphabetic order if and when there are additions
451 config X86_NUMACHIP
452         bool "Numascale NumaChip"
453         depends on X86_64
454         depends on X86_EXTENDED_PLATFORM
455         depends on NUMA
456         depends on SMP
457         depends on X86_X2APIC
458         depends on PCI_MMCONFIG
459         ---help---
460           Adds support for Numascale NumaChip large-SMP systems. Needed to
461           enable more than ~168 cores.
462           If you don't have one of these, you should say N here.
463 
464 config X86_VSMP
465         bool "ScaleMP vSMP"
466         select HYPERVISOR_GUEST
467         select PARAVIRT
468         depends on X86_64 && PCI
469         depends on X86_EXTENDED_PLATFORM
470         depends on SMP
471         ---help---
472           Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
473           supposed to run on these EM64T-based machines.  Only choose this option
474           if you have one of these machines.
475 
476 config X86_UV
477         bool "SGI Ultraviolet"
478         depends on X86_64
479         depends on X86_EXTENDED_PLATFORM
480         depends on NUMA
481         depends on EFI
482         depends on X86_X2APIC
483         depends on PCI
484         ---help---
485           This option is needed in order to support SGI Ultraviolet systems.
486           If you don't have one of these, you should say N here.
487 
488 # Following is an alphabetically sorted list of 32 bit extended platforms
489 # Please maintain the alphabetic order if and when there are additions
490 
491 config X86_GOLDFISH
492        bool "Goldfish (Virtual Platform)"
493        depends on X86_EXTENDED_PLATFORM
494        ---help---
495          Enable support for the Goldfish virtual platform used primarily
496          for Android development. Unless you are building for the Android
497          Goldfish emulator say N here.
498 
499 config X86_INTEL_CE
500         bool "CE4100 TV platform"
501         depends on PCI
502         depends on PCI_GODIRECT
503         depends on X86_IO_APIC
504         depends on X86_32
505         depends on X86_EXTENDED_PLATFORM
506         select X86_REBOOTFIXUPS
507         select OF
508         select OF_EARLY_FLATTREE
509         ---help---
510           Select for the Intel CE media processor (CE4100) SOC.
511           This option compiles in support for the CE4100 SOC for settop
512           boxes and media devices.
513 
514 config X86_INTEL_MID
515         bool "Intel MID platform support"
516         depends on X86_EXTENDED_PLATFORM
517         depends on X86_PLATFORM_DEVICES
518         depends on PCI
519         depends on X86_64 || (PCI_GOANY && X86_32)
520         depends on X86_IO_APIC
521         select SFI
522         select I2C
523         select DW_APB_TIMER
524         select APB_TIMER
525         select INTEL_SCU_IPC
526         select MFD_INTEL_MSIC
527         ---help---
528           Select to build a kernel capable of supporting Intel MID (Mobile
529           Internet Device) platform systems which do not have the PCI legacy
530           interfaces. If you are building for a PC class system say N here.
531 
532           Intel MID platforms are based on an Intel processor and chipset which
533           consume less power than most of the x86 derivatives.
534 
535 config X86_INTEL_QUARK
536         bool "Intel Quark platform support"
537         depends on X86_32
538         depends on X86_EXTENDED_PLATFORM
539         depends on X86_PLATFORM_DEVICES
540         depends on X86_TSC
541         depends on PCI
542         depends on PCI_GOANY
543         depends on X86_IO_APIC
544         select IOSF_MBI
545         select INTEL_IMR
546         select COMMON_CLK
547         ---help---
548           Select to include support for Quark X1000 SoC.
549           Say Y here if you have a Quark based system such as the Arduino
550           compatible Intel Galileo.
551 
552 config X86_INTEL_LPSS
553         bool "Intel Low Power Subsystem Support"
554         depends on X86 && ACPI
555         select COMMON_CLK
556         select PINCTRL
557         select IOSF_MBI
558         ---help---
559           Select to build support for Intel Low Power Subsystem such as
560           found on Intel Lynxpoint PCH. Selecting this option enables
561           things like clock tree (common clock framework) and pincontrol
562           which are needed by the LPSS peripheral drivers.
563 
564 config X86_AMD_PLATFORM_DEVICE
565         bool "AMD ACPI2Platform devices support"
566         depends on ACPI
567         select COMMON_CLK
568         select PINCTRL
569         ---help---
570           Select to interpret AMD specific ACPI device to platform device
571           such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
572           I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
573           implemented under PINCTRL subsystem.
574 
575 config IOSF_MBI
576         tristate "Intel SoC IOSF Sideband support for SoC platforms"
577         depends on PCI
578         ---help---
579           This option enables sideband register access support for Intel SoC
580           platforms. On these platforms the IOSF sideband is used in lieu of
581           MSR's for some register accesses, mostly but not limited to thermal
582           and power. Drivers may query the availability of this device to
583           determine if they need the sideband in order to work on these
584           platforms. The sideband is available on the following SoC products.
585           This list is not meant to be exclusive.
586            - BayTrail
587            - Braswell
588            - Quark
589 
590           You should say Y if you are running a kernel on one of these SoC's.
591 
592 config IOSF_MBI_DEBUG
593         bool "Enable IOSF sideband access through debugfs"
594         depends on IOSF_MBI && DEBUG_FS
595         ---help---
596           Select this option to expose the IOSF sideband access registers (MCR,
597           MDR, MCRX) through debugfs to write and read register information from
598           different units on the SoC. This is most useful for obtaining device
599           state information for debug and analysis. As this is a general access
600           mechanism, users of this option would have specific knowledge of the
601           device they want to access.
602 
603           If you don't require the option or are in doubt, say N.
604 
605 config X86_RDC321X
606         bool "RDC R-321x SoC"
607         depends on X86_32
608         depends on X86_EXTENDED_PLATFORM
609         select M486
610         select X86_REBOOTFIXUPS
611         ---help---
612           This option is needed for RDC R-321x system-on-chip, also known
613           as R-8610-(G).
614           If you don't have one of these chips, you should say N here.
615 
616 config X86_32_NON_STANDARD
617         bool "Support non-standard 32-bit SMP architectures"
618         depends on X86_32 && SMP
619         depends on X86_EXTENDED_PLATFORM
620         ---help---
621           This option compiles in the bigsmp and STA2X11 default
622           subarchitectures.  It is intended for a generic binary
623           kernel. If you select them all, kernel will probe it one by
624           one and will fallback to default.
625 
626 # Alphabetically sorted list of Non standard 32 bit platforms
627 
628 config X86_SUPPORTS_MEMORY_FAILURE
629         def_bool y
630         # MCE code calls memory_failure():
631         depends on X86_MCE
632         # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
633         # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
634         depends on X86_64 || !SPARSEMEM
635         select ARCH_SUPPORTS_MEMORY_FAILURE
636 
637 config STA2X11
638         bool "STA2X11 Companion Chip Support"
639         depends on X86_32_NON_STANDARD && PCI
640         select X86_DEV_DMA_OPS
641         select X86_DMA_REMAP
642         select SWIOTLB
643         select MFD_STA2X11
644         select GPIOLIB
645         default n
646         ---help---
647           This adds support for boards based on the STA2X11 IO-Hub,
648           a.k.a. "ConneXt". The chip is used in place of the standard
649           PC chipset, so all "standard" peripherals are missing. If this
650           option is selected the kernel will still be able to boot on
651           standard PC machines.
652 
653 config X86_32_IRIS
654         tristate "Eurobraille/Iris poweroff module"
655         depends on X86_32
656         ---help---
657           The Iris machines from EuroBraille do not have APM or ACPI support
658           to shut themselves down properly.  A special I/O sequence is
659           needed to do so, which is what this module does at
660           kernel shutdown.
661 
662           This is only for Iris machines from EuroBraille.
663 
664           If unused, say N.
665 
666 config SCHED_OMIT_FRAME_POINTER
667         def_bool y
668         prompt "Single-depth WCHAN output"
669         depends on X86
670         ---help---
671           Calculate simpler /proc/<PID>/wchan values. If this option
672           is disabled then wchan values will recurse back to the
673           caller function. This provides more accurate wchan values,
674           at the expense of slightly more scheduling overhead.
675 
676           If in doubt, say "Y".
677 
678 menuconfig HYPERVISOR_GUEST
679         bool "Linux guest support"
680         ---help---
681           Say Y here to enable options for running Linux under various hyper-
682           visors. This option enables basic hypervisor detection and platform
683           setup.
684 
685           If you say N, all options in this submenu will be skipped and
686           disabled, and Linux guest support won't be built in.
687 
688 if HYPERVISOR_GUEST
689 
690 config PARAVIRT
691         bool "Enable paravirtualization code"
692         ---help---
693           This changes the kernel so it can modify itself when it is run
694           under a hypervisor, potentially improving performance significantly
695           over full virtualization.  However, when run without a hypervisor
696           the kernel is theoretically slower and slightly larger.
697 
698 config PARAVIRT_DEBUG
699         bool "paravirt-ops debugging"
700         depends on PARAVIRT && DEBUG_KERNEL
701         ---help---
702           Enable to debug paravirt_ops internals.  Specifically, BUG if
703           a paravirt_op is missing when it is called.
704 
705 config PARAVIRT_SPINLOCKS
706         bool "Paravirtualization layer for spinlocks"
707         depends on PARAVIRT && SMP
708         select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
709         ---help---
710           Paravirtualized spinlocks allow a pvops backend to replace the
711           spinlock implementation with something virtualization-friendly
712           (for example, block the virtual CPU rather than spinning).
713 
714           It has a minimal impact on native kernels and gives a nice performance
715           benefit on paravirtualized KVM / Xen kernels.
716 
717           If you are unsure how to answer this question, answer Y.
718 
719 config QUEUED_LOCK_STAT
720         bool "Paravirt queued spinlock statistics"
721         depends on PARAVIRT_SPINLOCKS && DEBUG_FS && QUEUED_SPINLOCKS
722         ---help---
723           Enable the collection of statistical data on the slowpath
724           behavior of paravirtualized queued spinlocks and report
725           them on debugfs.
726 
727 source "arch/x86/xen/Kconfig"
728 
729 config KVM_GUEST
730         bool "KVM Guest support (including kvmclock)"
731         depends on PARAVIRT
732         select PARAVIRT_CLOCK
733         default y
734         ---help---
735           This option enables various optimizations for running under the KVM
736           hypervisor. It includes a paravirtualized clock, so that instead
737           of relying on a PIT (or probably other) emulation by the
738           underlying device model, the host provides the guest with
739           timing infrastructure such as time of day, and system time
740 
741 config KVM_DEBUG_FS
742         bool "Enable debug information for KVM Guests in debugfs"
743         depends on KVM_GUEST && DEBUG_FS
744         default n
745         ---help---
746           This option enables collection of various statistics for KVM guest.
747           Statistics are displayed in debugfs filesystem. Enabling this option
748           may incur significant overhead.
749 
750 source "arch/x86/lguest/Kconfig"
751 
752 config PARAVIRT_TIME_ACCOUNTING
753         bool "Paravirtual steal time accounting"
754         depends on PARAVIRT
755         default n
756         ---help---
757           Select this option to enable fine granularity task steal time
758           accounting. Time spent executing other tasks in parallel with
759           the current vCPU is discounted from the vCPU power. To account for
760           that, there can be a small performance impact.
761 
762           If in doubt, say N here.
763 
764 config PARAVIRT_CLOCK
765         bool
766 
767 endif #HYPERVISOR_GUEST
768 
769 config NO_BOOTMEM
770         def_bool y
771 
772 source "arch/x86/Kconfig.cpu"
773 
774 config HPET_TIMER
775         def_bool X86_64
776         prompt "HPET Timer Support" if X86_32
777         ---help---
778           Use the IA-PC HPET (High Precision Event Timer) to manage
779           time in preference to the PIT and RTC, if a HPET is
780           present.
781           HPET is the next generation timer replacing legacy 8254s.
782           The HPET provides a stable time base on SMP
783           systems, unlike the TSC, but it is more expensive to access,
784           as it is off-chip.  The interface used is documented
785           in the HPET spec, revision 1.
786 
787           You can safely choose Y here.  However, HPET will only be
788           activated if the platform and the BIOS support this feature.
789           Otherwise the 8254 will be used for timing services.
790 
791           Choose N to continue using the legacy 8254 timer.
792 
793 config HPET_EMULATE_RTC
794         def_bool y
795         depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
796 
797 config APB_TIMER
798        def_bool y if X86_INTEL_MID
799        prompt "Intel MID APB Timer Support" if X86_INTEL_MID
800        select DW_APB_TIMER
801        depends on X86_INTEL_MID && SFI
802        help
803          APB timer is the replacement for 8254, HPET on X86 MID platforms.
804          The APBT provides a stable time base on SMP
805          systems, unlike the TSC, but it is more expensive to access,
806          as it is off-chip. APB timers are always running regardless of CPU
807          C states, they are used as per CPU clockevent device when possible.
808 
809 # Mark as expert because too many people got it wrong.
810 # The code disables itself when not needed.
811 config DMI
812         default y
813         select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
814         bool "Enable DMI scanning" if EXPERT
815         ---help---
816           Enabled scanning of DMI to identify machine quirks. Say Y
817           here unless you have verified that your setup is not
818           affected by entries in the DMI blacklist. Required by PNP
819           BIOS code.
820 
821 config GART_IOMMU
822         bool "Old AMD GART IOMMU support"
823         select SWIOTLB
824         depends on X86_64 && PCI && AMD_NB
825         ---help---
826           Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
827           GART based hardware IOMMUs.
828 
829           The GART supports full DMA access for devices with 32-bit access
830           limitations, on systems with more than 3 GB. This is usually needed
831           for USB, sound, many IDE/SATA chipsets and some other devices.
832 
833           Newer systems typically have a modern AMD IOMMU, supported via
834           the CONFIG_AMD_IOMMU=y config option.
835 
836           In normal configurations this driver is only active when needed:
837           there's more than 3 GB of memory and the system contains a
838           32-bit limited device.
839 
840           If unsure, say Y.
841 
842 config CALGARY_IOMMU
843         bool "IBM Calgary IOMMU support"
844         select SWIOTLB
845         depends on X86_64 && PCI
846         ---help---
847           Support for hardware IOMMUs in IBM's xSeries x366 and x460
848           systems. Needed to run systems with more than 3GB of memory
849           properly with 32-bit PCI devices that do not support DAC
850           (Double Address Cycle). Calgary also supports bus level
851           isolation, where all DMAs pass through the IOMMU.  This
852           prevents them from going anywhere except their intended
853           destination. This catches hard-to-find kernel bugs and
854           mis-behaving drivers and devices that do not use the DMA-API
855           properly to set up their DMA buffers.  The IOMMU can be
856           turned off at boot time with the iommu=off parameter.
857           Normally the kernel will make the right choice by itself.
858           If unsure, say Y.
859 
860 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
861         def_bool y
862         prompt "Should Calgary be enabled by default?"
863         depends on CALGARY_IOMMU
864         ---help---
865           Should Calgary be enabled by default? if you choose 'y', Calgary
866           will be used (if it exists). If you choose 'n', Calgary will not be
867           used even if it exists. If you choose 'n' and would like to use
868           Calgary anyway, pass 'iommu=calgary' on the kernel command line.
869           If unsure, say Y.
870 
871 # need this always selected by IOMMU for the VIA workaround
872 config SWIOTLB
873         def_bool y if X86_64
874         ---help---
875           Support for software bounce buffers used on x86-64 systems
876           which don't have a hardware IOMMU. Using this PCI devices
877           which can only access 32-bits of memory can be used on systems
878           with more than 3 GB of memory.
879           If unsure, say Y.
880 
881 config IOMMU_HELPER
882         def_bool y
883         depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
884 
885 config MAXSMP
886         bool "Enable Maximum number of SMP Processors and NUMA Nodes"
887         depends on X86_64 && SMP && DEBUG_KERNEL
888         select CPUMASK_OFFSTACK
889         ---help---
890           Enable maximum number of CPUS and NUMA Nodes for this architecture.
891           If unsure, say N.
892 
893 config NR_CPUS
894         int "Maximum number of CPUs" if SMP && !MAXSMP
895         range 2 8 if SMP && X86_32 && !X86_BIGSMP
896         range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
897         range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
898         default "1" if !SMP
899         default "8192" if MAXSMP
900         default "32" if SMP && X86_BIGSMP
901         default "8" if SMP && X86_32
902         default "64" if SMP
903         ---help---
904           This allows you to specify the maximum number of CPUs which this
905           kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
906           supported value is 8192, otherwise the maximum value is 512.  The
907           minimum value which makes sense is 2.
908 
909           This is purely to save memory - each supported CPU adds
910           approximately eight kilobytes to the kernel image.
911 
912 config SCHED_SMT
913         bool "SMT (Hyperthreading) scheduler support"
914         depends on SMP
915         ---help---
916           SMT scheduler support improves the CPU scheduler's decision making
917           when dealing with Intel Pentium 4 chips with HyperThreading at a
918           cost of slightly increased overhead in some places. If unsure say
919           N here.
920 
921 config SCHED_MC
922         def_bool y
923         prompt "Multi-core scheduler support"
924         depends on SMP
925         ---help---
926           Multi-core scheduler support improves the CPU scheduler's decision
927           making when dealing with multi-core CPU chips at a cost of slightly
928           increased overhead in some places. If unsure say N here.
929 
930 source "kernel/Kconfig.preempt"
931 
932 config UP_LATE_INIT
933        def_bool y
934        depends on !SMP && X86_LOCAL_APIC
935 
936 config X86_UP_APIC
937         bool "Local APIC support on uniprocessors" if !PCI_MSI
938         default PCI_MSI
939         depends on X86_32 && !SMP && !X86_32_NON_STANDARD
940         ---help---
941           A local APIC (Advanced Programmable Interrupt Controller) is an
942           integrated interrupt controller in the CPU. If you have a single-CPU
943           system which has a processor with a local APIC, you can say Y here to
944           enable and use it. If you say Y here even though your machine doesn't
945           have a local APIC, then the kernel will still run with no slowdown at
946           all. The local APIC supports CPU-generated self-interrupts (timer,
947           performance counters), and the NMI watchdog which detects hard
948           lockups.
949 
950 config X86_UP_IOAPIC
951         bool "IO-APIC support on uniprocessors"
952         depends on X86_UP_APIC
953         ---help---
954           An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
955           SMP-capable replacement for PC-style interrupt controllers. Most
956           SMP systems and many recent uniprocessor systems have one.
957 
958           If you have a single-CPU system with an IO-APIC, you can say Y here
959           to use it. If you say Y here even though your machine doesn't have
960           an IO-APIC, then the kernel will still run with no slowdown at all.
961 
962 config X86_LOCAL_APIC
963         def_bool y
964         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
965         select IRQ_DOMAIN_HIERARCHY
966         select PCI_MSI_IRQ_DOMAIN if PCI_MSI
967 
968 config X86_IO_APIC
969         def_bool y
970         depends on X86_LOCAL_APIC || X86_UP_IOAPIC
971 
972 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
973         bool "Reroute for broken boot IRQs"
974         depends on X86_IO_APIC
975         ---help---
976           This option enables a workaround that fixes a source of
977           spurious interrupts. This is recommended when threaded
978           interrupt handling is used on systems where the generation of
979           superfluous "boot interrupts" cannot be disabled.
980 
981           Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
982           entry in the chipset's IO-APIC is masked (as, e.g. the RT
983           kernel does during interrupt handling). On chipsets where this
984           boot IRQ generation cannot be disabled, this workaround keeps
985           the original IRQ line masked so that only the equivalent "boot
986           IRQ" is delivered to the CPUs. The workaround also tells the
987           kernel to set up the IRQ handler on the boot IRQ line. In this
988           way only one interrupt is delivered to the kernel. Otherwise
989           the spurious second interrupt may cause the kernel to bring
990           down (vital) interrupt lines.
991 
992           Only affects "broken" chipsets. Interrupt sharing may be
993           increased on these systems.
994 
995 config X86_MCE
996         bool "Machine Check / overheating reporting"
997         select GENERIC_ALLOCATOR
998         default y
999         ---help---
1000           Machine Check support allows the processor to notify the
1001           kernel if it detects a problem (e.g. overheating, data corruption).
1002           The action the kernel takes depends on the severity of the problem,
1003           ranging from warning messages to halting the machine.
1004 
1005 config X86_MCE_INTEL
1006         def_bool y
1007         prompt "Intel MCE features"
1008         depends on X86_MCE && X86_LOCAL_APIC
1009         ---help---
1010            Additional support for intel specific MCE features such as
1011            the thermal monitor.
1012 
1013 config X86_MCE_AMD
1014         def_bool y
1015         prompt "AMD MCE features"
1016         depends on X86_MCE && X86_LOCAL_APIC
1017         ---help---
1018            Additional support for AMD specific MCE features such as
1019            the DRAM Error Threshold.
1020 
1021 config X86_ANCIENT_MCE
1022         bool "Support for old Pentium 5 / WinChip machine checks"
1023         depends on X86_32 && X86_MCE
1024         ---help---
1025           Include support for machine check handling on old Pentium 5 or WinChip
1026           systems. These typically need to be enabled explicitly on the command
1027           line.
1028 
1029 config X86_MCE_THRESHOLD
1030         depends on X86_MCE_AMD || X86_MCE_INTEL
1031         def_bool y
1032 
1033 config X86_MCE_INJECT
1034         depends on X86_MCE
1035         tristate "Machine check injector support"
1036         ---help---
1037           Provide support for injecting machine checks for testing purposes.
1038           If you don't know what a machine check is and you don't do kernel
1039           QA it is safe to say n.
1040 
1041 config X86_THERMAL_VECTOR
1042         def_bool y
1043         depends on X86_MCE_INTEL
1044 
1045 source "arch/x86/events/Kconfig"
1046 
1047 config X86_LEGACY_VM86
1048         bool "Legacy VM86 support"
1049         default n
1050         depends on X86_32
1051         ---help---
1052           This option allows user programs to put the CPU into V8086
1053           mode, which is an 80286-era approximation of 16-bit real mode.
1054 
1055           Some very old versions of X and/or vbetool require this option
1056           for user mode setting.  Similarly, DOSEMU will use it if
1057           available to accelerate real mode DOS programs.  However, any
1058           recent version of DOSEMU, X, or vbetool should be fully
1059           functional even without kernel VM86 support, as they will all
1060           fall back to software emulation. Nevertheless, if you are using
1061           a 16-bit DOS program where 16-bit performance matters, vm86
1062           mode might be faster than emulation and you might want to
1063           enable this option.
1064 
1065           Note that any app that works on a 64-bit kernel is unlikely to
1066           need this option, as 64-bit kernels don't, and can't, support
1067           V8086 mode. This option is also unrelated to 16-bit protected
1068           mode and is not needed to run most 16-bit programs under Wine.
1069 
1070           Enabling this option increases the complexity of the kernel
1071           and slows down exception handling a tiny bit.
1072 
1073           If unsure, say N here.
1074 
1075 config VM86
1076        bool
1077        default X86_LEGACY_VM86
1078 
1079 config X86_16BIT
1080         bool "Enable support for 16-bit segments" if EXPERT
1081         default y
1082         depends on MODIFY_LDT_SYSCALL
1083         ---help---
1084           This option is required by programs like Wine to run 16-bit
1085           protected mode legacy code on x86 processors.  Disabling
1086           this option saves about 300 bytes on i386, or around 6K text
1087           plus 16K runtime memory on x86-64,
1088 
1089 config X86_ESPFIX32
1090         def_bool y
1091         depends on X86_16BIT && X86_32
1092 
1093 config X86_ESPFIX64
1094         def_bool y
1095         depends on X86_16BIT && X86_64
1096 
1097 config X86_VSYSCALL_EMULATION
1098        bool "Enable vsyscall emulation" if EXPERT
1099        default y
1100        depends on X86_64
1101        ---help---
1102          This enables emulation of the legacy vsyscall page.  Disabling
1103          it is roughly equivalent to booting with vsyscall=none, except
1104          that it will also disable the helpful warning if a program
1105          tries to use a vsyscall.  With this option set to N, offending
1106          programs will just segfault, citing addresses of the form
1107          0xffffffffff600?00.
1108 
1109          This option is required by many programs built before 2013, and
1110          care should be used even with newer programs if set to N.
1111 
1112          Disabling this option saves about 7K of kernel size and
1113          possibly 4K of additional runtime pagetable memory.
1114 
1115 config TOSHIBA
1116         tristate "Toshiba Laptop support"
1117         depends on X86_32
1118         ---help---
1119           This adds a driver to safely access the System Management Mode of
1120           the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1121           not work on models with a Phoenix BIOS. The System Management Mode
1122           is used to set the BIOS and power saving options on Toshiba portables.
1123 
1124           For information on utilities to make use of this driver see the
1125           Toshiba Linux utilities web site at:
1126           <http://www.buzzard.org.uk/toshiba/>.
1127 
1128           Say Y if you intend to run this kernel on a Toshiba portable.
1129           Say N otherwise.
1130 
1131 config I8K
1132         tristate "Dell i8k legacy laptop support"
1133         select HWMON
1134         select SENSORS_DELL_SMM
1135         ---help---
1136           This option enables legacy /proc/i8k userspace interface in hwmon
1137           dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1138           temperature and allows controlling fan speeds of Dell laptops via
1139           System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1140           it reports also power and hotkey status. For fan speed control is
1141           needed userspace package i8kutils.
1142 
1143           Say Y if you intend to run this kernel on old Dell laptops or want to
1144           use userspace package i8kutils.
1145           Say N otherwise.
1146 
1147 config X86_REBOOTFIXUPS
1148         bool "Enable X86 board specific fixups for reboot"
1149         depends on X86_32
1150         ---help---
1151           This enables chipset and/or board specific fixups to be done
1152           in order to get reboot to work correctly. This is only needed on
1153           some combinations of hardware and BIOS. The symptom, for which
1154           this config is intended, is when reboot ends with a stalled/hung
1155           system.
1156 
1157           Currently, the only fixup is for the Geode machines using
1158           CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1159 
1160           Say Y if you want to enable the fixup. Currently, it's safe to
1161           enable this option even if you don't need it.
1162           Say N otherwise.
1163 
1164 config MICROCODE
1165         bool "CPU microcode loading support"
1166         default y
1167         depends on CPU_SUP_AMD || CPU_SUP_INTEL
1168         select FW_LOADER
1169         ---help---
1170           If you say Y here, you will be able to update the microcode on
1171           Intel and AMD processors. The Intel support is for the IA32 family,
1172           e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1173           AMD support is for families 0x10 and later. You will obviously need
1174           the actual microcode binary data itself which is not shipped with
1175           the Linux kernel.
1176 
1177           The preferred method to load microcode from a detached initrd is described
1178           in Documentation/x86/early-microcode.txt. For that you need to enable
1179           CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1180           initrd for microcode blobs.
1181 
1182           In addition, you can build-in the microcode into the kernel. For that you
1183           need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1184           to the CONFIG_EXTRA_FIRMWARE config option.
1185 
1186 config MICROCODE_INTEL
1187         bool "Intel microcode loading support"
1188         depends on MICROCODE
1189         default MICROCODE
1190         select FW_LOADER
1191         ---help---
1192           This options enables microcode patch loading support for Intel
1193           processors.
1194 
1195           For the current Intel microcode data package go to
1196           <https://downloadcenter.intel.com> and search for
1197           'Linux Processor Microcode Data File'.
1198 
1199 config MICROCODE_AMD
1200         bool "AMD microcode loading support"
1201         depends on MICROCODE
1202         select FW_LOADER
1203         ---help---
1204           If you select this option, microcode patch loading support for AMD
1205           processors will be enabled.
1206 
1207 config MICROCODE_OLD_INTERFACE
1208         def_bool y
1209         depends on MICROCODE
1210 
1211 config X86_MSR
1212         tristate "/dev/cpu/*/msr - Model-specific register support"
1213         ---help---
1214           This device gives privileged processes access to the x86
1215           Model-Specific Registers (MSRs).  It is a character device with
1216           major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1217           MSR accesses are directed to a specific CPU on multi-processor
1218           systems.
1219 
1220 config X86_CPUID
1221         tristate "/dev/cpu/*/cpuid - CPU information support"
1222         ---help---
1223           This device gives processes access to the x86 CPUID instruction to
1224           be executed on a specific processor.  It is a character device
1225           with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1226           /dev/cpu/31/cpuid.
1227 
1228 choice
1229         prompt "High Memory Support"
1230         default HIGHMEM4G
1231         depends on X86_32
1232 
1233 config NOHIGHMEM
1234         bool "off"
1235         ---help---
1236           Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1237           However, the address space of 32-bit x86 processors is only 4
1238           Gigabytes large. That means that, if you have a large amount of
1239           physical memory, not all of it can be "permanently mapped" by the
1240           kernel. The physical memory that's not permanently mapped is called
1241           "high memory".
1242 
1243           If you are compiling a kernel which will never run on a machine with
1244           more than 1 Gigabyte total physical RAM, answer "off" here (default
1245           choice and suitable for most users). This will result in a "3GB/1GB"
1246           split: 3GB are mapped so that each process sees a 3GB virtual memory
1247           space and the remaining part of the 4GB virtual memory space is used
1248           by the kernel to permanently map as much physical memory as
1249           possible.
1250 
1251           If the machine has between 1 and 4 Gigabytes physical RAM, then
1252           answer "4GB" here.
1253 
1254           If more than 4 Gigabytes is used then answer "64GB" here. This
1255           selection turns Intel PAE (Physical Address Extension) mode on.
1256           PAE implements 3-level paging on IA32 processors. PAE is fully
1257           supported by Linux, PAE mode is implemented on all recent Intel
1258           processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1259           then the kernel will not boot on CPUs that don't support PAE!
1260 
1261           The actual amount of total physical memory will either be
1262           auto detected or can be forced by using a kernel command line option
1263           such as "mem=256M". (Try "man bootparam" or see the documentation of
1264           your boot loader (lilo or loadlin) about how to pass options to the
1265           kernel at boot time.)
1266 
1267           If unsure, say "off".
1268 
1269 config HIGHMEM4G
1270         bool "4GB"
1271         ---help---
1272           Select this if you have a 32-bit processor and between 1 and 4
1273           gigabytes of physical RAM.
1274 
1275 config HIGHMEM64G
1276         bool "64GB"
1277         depends on !M486
1278         select X86_PAE
1279         ---help---
1280           Select this if you have a 32-bit processor and more than 4
1281           gigabytes of physical RAM.
1282 
1283 endchoice
1284 
1285 choice
1286         prompt "Memory split" if EXPERT
1287         default VMSPLIT_3G
1288         depends on X86_32
1289         ---help---
1290           Select the desired split between kernel and user memory.
1291 
1292           If the address range available to the kernel is less than the
1293           physical memory installed, the remaining memory will be available
1294           as "high memory". Accessing high memory is a little more costly
1295           than low memory, as it needs to be mapped into the kernel first.
1296           Note that increasing the kernel address space limits the range
1297           available to user programs, making the address space there
1298           tighter.  Selecting anything other than the default 3G/1G split
1299           will also likely make your kernel incompatible with binary-only
1300           kernel modules.
1301 
1302           If you are not absolutely sure what you are doing, leave this
1303           option alone!
1304 
1305         config VMSPLIT_3G
1306                 bool "3G/1G user/kernel split"
1307         config VMSPLIT_3G_OPT
1308                 depends on !X86_PAE
1309                 bool "3G/1G user/kernel split (for full 1G low memory)"
1310         config VMSPLIT_2G
1311                 bool "2G/2G user/kernel split"
1312         config VMSPLIT_2G_OPT
1313                 depends on !X86_PAE
1314                 bool "2G/2G user/kernel split (for full 2G low memory)"
1315         config VMSPLIT_1G
1316                 bool "1G/3G user/kernel split"
1317 endchoice
1318 
1319 config PAGE_OFFSET
1320         hex
1321         default 0xB0000000 if VMSPLIT_3G_OPT
1322         default 0x80000000 if VMSPLIT_2G
1323         default 0x78000000 if VMSPLIT_2G_OPT
1324         default 0x40000000 if VMSPLIT_1G
1325         default 0xC0000000
1326         depends on X86_32
1327 
1328 config HIGHMEM
1329         def_bool y
1330         depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1331 
1332 config X86_PAE
1333         bool "PAE (Physical Address Extension) Support"
1334         depends on X86_32 && !HIGHMEM4G
1335         select SWIOTLB
1336         ---help---
1337           PAE is required for NX support, and furthermore enables
1338           larger swapspace support for non-overcommit purposes. It
1339           has the cost of more pagetable lookup overhead, and also
1340           consumes more pagetable space per process.
1341 
1342 config ARCH_PHYS_ADDR_T_64BIT
1343         def_bool y
1344         depends on X86_64 || X86_PAE
1345 
1346 config ARCH_DMA_ADDR_T_64BIT
1347         def_bool y
1348         depends on X86_64 || HIGHMEM64G
1349 
1350 config X86_DIRECT_GBPAGES
1351         def_bool y
1352         depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1353         ---help---
1354           Certain kernel features effectively disable kernel
1355           linear 1 GB mappings (even if the CPU otherwise
1356           supports them), so don't confuse the user by printing
1357           that we have them enabled.
1358 
1359 # Common NUMA Features
1360 config NUMA
1361         bool "Numa Memory Allocation and Scheduler Support"
1362         depends on SMP
1363         depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1364         default y if X86_BIGSMP
1365         ---help---
1366           Enable NUMA (Non Uniform Memory Access) support.
1367 
1368           The kernel will try to allocate memory used by a CPU on the
1369           local memory controller of the CPU and add some more
1370           NUMA awareness to the kernel.
1371 
1372           For 64-bit this is recommended if the system is Intel Core i7
1373           (or later), AMD Opteron, or EM64T NUMA.
1374 
1375           For 32-bit this is only needed if you boot a 32-bit
1376           kernel on a 64-bit NUMA platform.
1377 
1378           Otherwise, you should say N.
1379 
1380 config AMD_NUMA
1381         def_bool y
1382         prompt "Old style AMD Opteron NUMA detection"
1383         depends on X86_64 && NUMA && PCI
1384         ---help---
1385           Enable AMD NUMA node topology detection.  You should say Y here if
1386           you have a multi processor AMD system. This uses an old method to
1387           read the NUMA configuration directly from the builtin Northbridge
1388           of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1389           which also takes priority if both are compiled in.
1390 
1391 config X86_64_ACPI_NUMA
1392         def_bool y
1393         prompt "ACPI NUMA detection"
1394         depends on X86_64 && NUMA && ACPI && PCI
1395         select ACPI_NUMA
1396         ---help---
1397           Enable ACPI SRAT based node topology detection.
1398 
1399 # Some NUMA nodes have memory ranges that span
1400 # other nodes.  Even though a pfn is valid and
1401 # between a node's start and end pfns, it may not
1402 # reside on that node.  See memmap_init_zone()
1403 # for details.
1404 config NODES_SPAN_OTHER_NODES
1405         def_bool y
1406         depends on X86_64_ACPI_NUMA
1407 
1408 config NUMA_EMU
1409         bool "NUMA emulation"
1410         depends on NUMA
1411         ---help---
1412           Enable NUMA emulation. A flat machine will be split
1413           into virtual nodes when booted with "numa=fake=N", where N is the
1414           number of nodes. This is only useful for debugging.
1415 
1416 config NODES_SHIFT
1417         int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1418         range 1 10
1419         default "10" if MAXSMP
1420         default "6" if X86_64
1421         default "3"
1422         depends on NEED_MULTIPLE_NODES
1423         ---help---
1424           Specify the maximum number of NUMA Nodes available on the target
1425           system.  Increases memory reserved to accommodate various tables.
1426 
1427 config ARCH_HAVE_MEMORY_PRESENT
1428         def_bool y
1429         depends on X86_32 && DISCONTIGMEM
1430 
1431 config NEED_NODE_MEMMAP_SIZE
1432         def_bool y
1433         depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1434 
1435 config ARCH_FLATMEM_ENABLE
1436         def_bool y
1437         depends on X86_32 && !NUMA
1438 
1439 config ARCH_DISCONTIGMEM_ENABLE
1440         def_bool y
1441         depends on NUMA && X86_32
1442 
1443 config ARCH_DISCONTIGMEM_DEFAULT
1444         def_bool y
1445         depends on NUMA && X86_32
1446 
1447 config ARCH_SPARSEMEM_ENABLE
1448         def_bool y
1449         depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1450         select SPARSEMEM_STATIC if X86_32
1451         select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1452 
1453 config ARCH_SPARSEMEM_DEFAULT
1454         def_bool y
1455         depends on X86_64
1456 
1457 config ARCH_SELECT_MEMORY_MODEL
1458         def_bool y
1459         depends on ARCH_SPARSEMEM_ENABLE
1460 
1461 config ARCH_MEMORY_PROBE
1462         bool "Enable sysfs memory/probe interface"
1463         depends on X86_64 && MEMORY_HOTPLUG
1464         help
1465           This option enables a sysfs memory/probe interface for testing.
1466           See Documentation/memory-hotplug.txt for more information.
1467           If you are unsure how to answer this question, answer N.
1468 
1469 config ARCH_PROC_KCORE_TEXT
1470         def_bool y
1471         depends on X86_64 && PROC_KCORE
1472 
1473 config ILLEGAL_POINTER_VALUE
1474        hex
1475        default 0 if X86_32
1476        default 0xdead000000000000 if X86_64
1477 
1478 source "mm/Kconfig"
1479 
1480 config X86_PMEM_LEGACY_DEVICE
1481         bool
1482 
1483 config X86_PMEM_LEGACY
1484         tristate "Support non-standard NVDIMMs and ADR protected memory"
1485         depends on PHYS_ADDR_T_64BIT
1486         depends on BLK_DEV
1487         select X86_PMEM_LEGACY_DEVICE
1488         select LIBNVDIMM
1489         help
1490           Treat memory marked using the non-standard e820 type of 12 as used
1491           by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1492           The kernel will offer these regions to the 'pmem' driver so
1493           they can be used for persistent storage.
1494 
1495           Say Y if unsure.
1496 
1497 config HIGHPTE
1498         bool "Allocate 3rd-level pagetables from highmem"
1499         depends on HIGHMEM
1500         ---help---
1501           The VM uses one page table entry for each page of physical memory.
1502           For systems with a lot of RAM, this can be wasteful of precious
1503           low memory.  Setting this option will put user-space page table
1504           entries in high memory.
1505 
1506 config X86_CHECK_BIOS_CORRUPTION
1507         bool "Check for low memory corruption"
1508         ---help---
1509           Periodically check for memory corruption in low memory, which
1510           is suspected to be caused by BIOS.  Even when enabled in the
1511           configuration, it is disabled at runtime.  Enable it by
1512           setting "memory_corruption_check=1" on the kernel command
1513           line.  By default it scans the low 64k of memory every 60
1514           seconds; see the memory_corruption_check_size and
1515           memory_corruption_check_period parameters in
1516           Documentation/kernel-parameters.txt to adjust this.
1517 
1518           When enabled with the default parameters, this option has
1519           almost no overhead, as it reserves a relatively small amount
1520           of memory and scans it infrequently.  It both detects corruption
1521           and prevents it from affecting the running system.
1522 
1523           It is, however, intended as a diagnostic tool; if repeatable
1524           BIOS-originated corruption always affects the same memory,
1525           you can use memmap= to prevent the kernel from using that
1526           memory.
1527 
1528 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1529         bool "Set the default setting of memory_corruption_check"
1530         depends on X86_CHECK_BIOS_CORRUPTION
1531         default y
1532         ---help---
1533           Set whether the default state of memory_corruption_check is
1534           on or off.
1535 
1536 config X86_RESERVE_LOW
1537         int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1538         default 64
1539         range 4 640
1540         ---help---
1541           Specify the amount of low memory to reserve for the BIOS.
1542 
1543           The first page contains BIOS data structures that the kernel
1544           must not use, so that page must always be reserved.
1545 
1546           By default we reserve the first 64K of physical RAM, as a
1547           number of BIOSes are known to corrupt that memory range
1548           during events such as suspend/resume or monitor cable
1549           insertion, so it must not be used by the kernel.
1550 
1551           You can set this to 4 if you are absolutely sure that you
1552           trust the BIOS to get all its memory reservations and usages
1553           right.  If you know your BIOS have problems beyond the
1554           default 64K area, you can set this to 640 to avoid using the
1555           entire low memory range.
1556 
1557           If you have doubts about the BIOS (e.g. suspend/resume does
1558           not work or there's kernel crashes after certain hardware
1559           hotplug events) then you might want to enable
1560           X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1561           typical corruption patterns.
1562 
1563           Leave this to the default value of 64 if you are unsure.
1564 
1565 config MATH_EMULATION
1566         bool
1567         depends on MODIFY_LDT_SYSCALL
1568         prompt "Math emulation" if X86_32
1569         ---help---
1570           Linux can emulate a math coprocessor (used for floating point
1571           operations) if you don't have one. 486DX and Pentium processors have
1572           a math coprocessor built in, 486SX and 386 do not, unless you added
1573           a 487DX or 387, respectively. (The messages during boot time can
1574           give you some hints here ["man dmesg"].) Everyone needs either a
1575           coprocessor or this emulation.
1576 
1577           If you don't have a math coprocessor, you need to say Y here; if you
1578           say Y here even though you have a coprocessor, the coprocessor will
1579           be used nevertheless. (This behavior can be changed with the kernel
1580           command line option "no387", which comes handy if your coprocessor
1581           is broken. Try "man bootparam" or see the documentation of your boot
1582           loader (lilo or loadlin) about how to pass options to the kernel at
1583           boot time.) This means that it is a good idea to say Y here if you
1584           intend to use this kernel on different machines.
1585 
1586           More information about the internals of the Linux math coprocessor
1587           emulation can be found in <file:arch/x86/math-emu/README>.
1588 
1589           If you are not sure, say Y; apart from resulting in a 66 KB bigger
1590           kernel, it won't hurt.
1591 
1592 config MTRR
1593         def_bool y
1594         prompt "MTRR (Memory Type Range Register) support" if EXPERT
1595         ---help---
1596           On Intel P6 family processors (Pentium Pro, Pentium II and later)
1597           the Memory Type Range Registers (MTRRs) may be used to control
1598           processor access to memory ranges. This is most useful if you have
1599           a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1600           allows bus write transfers to be combined into a larger transfer
1601           before bursting over the PCI/AGP bus. This can increase performance
1602           of image write operations 2.5 times or more. Saying Y here creates a
1603           /proc/mtrr file which may be used to manipulate your processor's
1604           MTRRs. Typically the X server should use this.
1605 
1606           This code has a reasonably generic interface so that similar
1607           control registers on other processors can be easily supported
1608           as well:
1609 
1610           The Cyrix 6x86, 6x86MX and M II processors have Address Range
1611           Registers (ARRs) which provide a similar functionality to MTRRs. For
1612           these, the ARRs are used to emulate the MTRRs.
1613           The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1614           MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1615           write-combining. All of these processors are supported by this code
1616           and it makes sense to say Y here if you have one of them.
1617 
1618           Saying Y here also fixes a problem with buggy SMP BIOSes which only
1619           set the MTRRs for the boot CPU and not for the secondary CPUs. This
1620           can lead to all sorts of problems, so it's good to say Y here.
1621 
1622           You can safely say Y even if your machine doesn't have MTRRs, you'll
1623           just add about 9 KB to your kernel.
1624 
1625           See <file:Documentation/x86/mtrr.txt> for more information.
1626 
1627 config MTRR_SANITIZER
1628         def_bool y
1629         prompt "MTRR cleanup support"
1630         depends on MTRR
1631         ---help---
1632           Convert MTRR layout from continuous to discrete, so X drivers can
1633           add writeback entries.
1634 
1635           Can be disabled with disable_mtrr_cleanup on the kernel command line.
1636           The largest mtrr entry size for a continuous block can be set with
1637           mtrr_chunk_size.
1638 
1639           If unsure, say Y.
1640 
1641 config MTRR_SANITIZER_ENABLE_DEFAULT
1642         int "MTRR cleanup enable value (0-1)"
1643         range 0 1
1644         default "0"
1645         depends on MTRR_SANITIZER
1646         ---help---
1647           Enable mtrr cleanup default value
1648 
1649 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1650         int "MTRR cleanup spare reg num (0-7)"
1651         range 0 7
1652         default "1"
1653         depends on MTRR_SANITIZER
1654         ---help---
1655           mtrr cleanup spare entries default, it can be changed via
1656           mtrr_spare_reg_nr=N on the kernel command line.
1657 
1658 config X86_PAT
1659         def_bool y
1660         prompt "x86 PAT support" if EXPERT
1661         depends on MTRR
1662         ---help---
1663           Use PAT attributes to setup page level cache control.
1664 
1665           PATs are the modern equivalents of MTRRs and are much more
1666           flexible than MTRRs.
1667 
1668           Say N here if you see bootup problems (boot crash, boot hang,
1669           spontaneous reboots) or a non-working video driver.
1670 
1671           If unsure, say Y.
1672 
1673 config ARCH_USES_PG_UNCACHED
1674         def_bool y
1675         depends on X86_PAT
1676 
1677 config ARCH_RANDOM
1678         def_bool y
1679         prompt "x86 architectural random number generator" if EXPERT
1680         ---help---
1681           Enable the x86 architectural RDRAND instruction
1682           (Intel Bull Mountain technology) to generate random numbers.
1683           If supported, this is a high bandwidth, cryptographically
1684           secure hardware random number generator.
1685 
1686 config X86_SMAP
1687         def_bool y
1688         prompt "Supervisor Mode Access Prevention" if EXPERT
1689         ---help---
1690           Supervisor Mode Access Prevention (SMAP) is a security
1691           feature in newer Intel processors.  There is a small
1692           performance cost if this enabled and turned on; there is
1693           also a small increase in the kernel size if this is enabled.
1694 
1695           If unsure, say Y.
1696 
1697 config X86_INTEL_MPX
1698         prompt "Intel MPX (Memory Protection Extensions)"
1699         def_bool n
1700         depends on CPU_SUP_INTEL
1701         ---help---
1702           MPX provides hardware features that can be used in
1703           conjunction with compiler-instrumented code to check
1704           memory references.  It is designed to detect buffer
1705           overflow or underflow bugs.
1706 
1707           This option enables running applications which are
1708           instrumented or otherwise use MPX.  It does not use MPX
1709           itself inside the kernel or to protect the kernel
1710           against bad memory references.
1711 
1712           Enabling this option will make the kernel larger:
1713           ~8k of kernel text and 36 bytes of data on a 64-bit
1714           defconfig.  It adds a long to the 'mm_struct' which
1715           will increase the kernel memory overhead of each
1716           process and adds some branches to paths used during
1717           exec() and munmap().
1718 
1719           For details, see Documentation/x86/intel_mpx.txt
1720 
1721           If unsure, say N.
1722 
1723 config X86_INTEL_MEMORY_PROTECTION_KEYS
1724         prompt "Intel Memory Protection Keys"
1725         def_bool y
1726         # Note: only available in 64-bit mode
1727         depends on CPU_SUP_INTEL && X86_64
1728         ---help---
1729           Memory Protection Keys provides a mechanism for enforcing
1730           page-based protections, but without requiring modification of the
1731           page tables when an application changes protection domains.
1732 
1733           For details, see Documentation/x86/protection-keys.txt
1734 
1735           If unsure, say y.
1736 
1737 config EFI
1738         bool "EFI runtime service support"
1739         depends on ACPI
1740         select UCS2_STRING
1741         select EFI_RUNTIME_WRAPPERS
1742         ---help---
1743           This enables the kernel to use EFI runtime services that are
1744           available (such as the EFI variable services).
1745 
1746           This option is only useful on systems that have EFI firmware.
1747           In addition, you should use the latest ELILO loader available
1748           at <http://elilo.sourceforge.net> in order to take advantage
1749           of EFI runtime services. However, even with this option, the
1750           resultant kernel should continue to boot on existing non-EFI
1751           platforms.
1752 
1753 config EFI_STUB
1754        bool "EFI stub support"
1755        depends on EFI && !X86_USE_3DNOW
1756        select RELOCATABLE
1757        ---help---
1758           This kernel feature allows a bzImage to be loaded directly
1759           by EFI firmware without the use of a bootloader.
1760 
1761           See Documentation/efi-stub.txt for more information.
1762 
1763 config EFI_MIXED
1764         bool "EFI mixed-mode support"
1765         depends on EFI_STUB && X86_64
1766         ---help---
1767            Enabling this feature allows a 64-bit kernel to be booted
1768            on a 32-bit firmware, provided that your CPU supports 64-bit
1769            mode.
1770 
1771            Note that it is not possible to boot a mixed-mode enabled
1772            kernel via the EFI boot stub - a bootloader that supports
1773            the EFI handover protocol must be used.
1774 
1775            If unsure, say N.
1776 
1777 config SECCOMP
1778         def_bool y
1779         prompt "Enable seccomp to safely compute untrusted bytecode"
1780         ---help---
1781           This kernel feature is useful for number crunching applications
1782           that may need to compute untrusted bytecode during their
1783           execution. By using pipes or other transports made available to
1784           the process as file descriptors supporting the read/write
1785           syscalls, it's possible to isolate those applications in
1786           their own address space using seccomp. Once seccomp is
1787           enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1788           and the task is only allowed to execute a few safe syscalls
1789           defined by each seccomp mode.
1790 
1791           If unsure, say Y. Only embedded should say N here.
1792 
1793 source kernel/Kconfig.hz
1794 
1795 config KEXEC
1796         bool "kexec system call"
1797         select KEXEC_CORE
1798         ---help---
1799           kexec is a system call that implements the ability to shutdown your
1800           current kernel, and to start another kernel.  It is like a reboot
1801           but it is independent of the system firmware.   And like a reboot
1802           you can start any kernel with it, not just Linux.
1803 
1804           The name comes from the similarity to the exec system call.
1805 
1806           It is an ongoing process to be certain the hardware in a machine
1807           is properly shutdown, so do not be surprised if this code does not
1808           initially work for you.  As of this writing the exact hardware
1809           interface is strongly in flux, so no good recommendation can be
1810           made.
1811 
1812 config KEXEC_FILE
1813         bool "kexec file based system call"
1814         select KEXEC_CORE
1815         select BUILD_BIN2C
1816         depends on X86_64
1817         depends on CRYPTO=y
1818         depends on CRYPTO_SHA256=y
1819         ---help---
1820           This is new version of kexec system call. This system call is
1821           file based and takes file descriptors as system call argument
1822           for kernel and initramfs as opposed to list of segments as
1823           accepted by previous system call.
1824 
1825 config KEXEC_VERIFY_SIG
1826         bool "Verify kernel signature during kexec_file_load() syscall"
1827         depends on KEXEC_FILE
1828         ---help---
1829           This option makes kernel signature verification mandatory for
1830           the kexec_file_load() syscall.
1831 
1832           In addition to that option, you need to enable signature
1833           verification for the corresponding kernel image type being
1834           loaded in order for this to work.
1835 
1836 config KEXEC_BZIMAGE_VERIFY_SIG
1837         bool "Enable bzImage signature verification support"
1838         depends on KEXEC_VERIFY_SIG
1839         depends on SIGNED_PE_FILE_VERIFICATION
1840         select SYSTEM_TRUSTED_KEYRING
1841         ---help---
1842           Enable bzImage signature verification support.
1843 
1844 config CRASH_DUMP
1845         bool "kernel crash dumps"
1846         depends on X86_64 || (X86_32 && HIGHMEM)
1847         ---help---
1848           Generate crash dump after being started by kexec.
1849           This should be normally only set in special crash dump kernels
1850           which are loaded in the main kernel with kexec-tools into
1851           a specially reserved region and then later executed after
1852           a crash by kdump/kexec. The crash dump kernel must be compiled
1853           to a memory address not used by the main kernel or BIOS using
1854           PHYSICAL_START, or it must be built as a relocatable image
1855           (CONFIG_RELOCATABLE=y).
1856           For more details see Documentation/kdump/kdump.txt
1857 
1858 config KEXEC_JUMP
1859         bool "kexec jump"
1860         depends on KEXEC && HIBERNATION
1861         ---help---
1862           Jump between original kernel and kexeced kernel and invoke
1863           code in physical address mode via KEXEC
1864 
1865 config PHYSICAL_START
1866         hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1867         default "0x1000000"
1868         ---help---
1869           This gives the physical address where the kernel is loaded.
1870 
1871           If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1872           bzImage will decompress itself to above physical address and
1873           run from there. Otherwise, bzImage will run from the address where
1874           it has been loaded by the boot loader and will ignore above physical
1875           address.
1876 
1877           In normal kdump cases one does not have to set/change this option
1878           as now bzImage can be compiled as a completely relocatable image
1879           (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1880           address. This option is mainly useful for the folks who don't want
1881           to use a bzImage for capturing the crash dump and want to use a
1882           vmlinux instead. vmlinux is not relocatable hence a kernel needs
1883           to be specifically compiled to run from a specific memory area
1884           (normally a reserved region) and this option comes handy.
1885 
1886           So if you are using bzImage for capturing the crash dump,
1887           leave the value here unchanged to 0x1000000 and set
1888           CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
1889           for capturing the crash dump change this value to start of
1890           the reserved region.  In other words, it can be set based on
1891           the "X" value as specified in the "crashkernel=YM@XM"
1892           command line boot parameter passed to the panic-ed
1893           kernel. Please take a look at Documentation/kdump/kdump.txt
1894           for more details about crash dumps.
1895 
1896           Usage of bzImage for capturing the crash dump is recommended as
1897           one does not have to build two kernels. Same kernel can be used
1898           as production kernel and capture kernel. Above option should have
1899           gone away after relocatable bzImage support is introduced. But it
1900           is present because there are users out there who continue to use
1901           vmlinux for dump capture. This option should go away down the
1902           line.
1903 
1904           Don't change this unless you know what you are doing.
1905 
1906 config RELOCATABLE
1907         bool "Build a relocatable kernel"
1908         default y
1909         ---help---
1910           This builds a kernel image that retains relocation information
1911           so it can be loaded someplace besides the default 1MB.
1912           The relocations tend to make the kernel binary about 10% larger,
1913           but are discarded at runtime.
1914 
1915           One use is for the kexec on panic case where the recovery kernel
1916           must live at a different physical address than the primary
1917           kernel.
1918 
1919           Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1920           it has been loaded at and the compile time physical address
1921           (CONFIG_PHYSICAL_START) is used as the minimum location.
1922 
1923 config RANDOMIZE_BASE
1924         bool "Randomize the address of the kernel image (KASLR)"
1925         depends on RELOCATABLE
1926         default n
1927         ---help---
1928           In support of Kernel Address Space Layout Randomization (KASLR),
1929           this randomizes the physical address at which the kernel image
1930           is decompressed and the virtual address where the kernel
1931           image is mapped, as a security feature that deters exploit
1932           attempts relying on knowledge of the location of kernel
1933           code internals.
1934 
1935           On 64-bit, the kernel physical and virtual addresses are
1936           randomized separately. The physical address will be anywhere
1937           between 16MB and the top of physical memory (up to 64TB). The
1938           virtual address will be randomized from 16MB up to 1GB (9 bits
1939           of entropy). Note that this also reduces the memory space
1940           available to kernel modules from 1.5GB to 1GB.
1941 
1942           On 32-bit, the kernel physical and virtual addresses are
1943           randomized together. They will be randomized from 16MB up to
1944           512MB (8 bits of entropy).
1945 
1946           Entropy is generated using the RDRAND instruction if it is
1947           supported. If RDTSC is supported, its value is mixed into
1948           the entropy pool as well. If neither RDRAND nor RDTSC are
1949           supported, then entropy is read from the i8254 timer. The
1950           usable entropy is limited by the kernel being built using
1951           2GB addressing, and that PHYSICAL_ALIGN must be at a
1952           minimum of 2MB. As a result, only 10 bits of entropy are
1953           theoretically possible, but the implementations are further
1954           limited due to memory layouts.
1955 
1956           If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot
1957           time. To enable it, boot with "kaslr" on the kernel command
1958           line (which will also disable hibernation).
1959 
1960           If unsure, say N.
1961 
1962 # Relocation on x86 needs some additional build support
1963 config X86_NEED_RELOCS
1964         def_bool y
1965         depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1966 
1967 config PHYSICAL_ALIGN
1968         hex "Alignment value to which kernel should be aligned"
1969         default "0x200000"
1970         range 0x2000 0x1000000 if X86_32
1971         range 0x200000 0x1000000 if X86_64
1972         ---help---
1973           This value puts the alignment restrictions on physical address
1974           where kernel is loaded and run from. Kernel is compiled for an
1975           address which meets above alignment restriction.
1976 
1977           If bootloader loads the kernel at a non-aligned address and
1978           CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1979           address aligned to above value and run from there.
1980 
1981           If bootloader loads the kernel at a non-aligned address and
1982           CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1983           load address and decompress itself to the address it has been
1984           compiled for and run from there. The address for which kernel is
1985           compiled already meets above alignment restrictions. Hence the
1986           end result is that kernel runs from a physical address meeting
1987           above alignment restrictions.
1988 
1989           On 32-bit this value must be a multiple of 0x2000. On 64-bit
1990           this value must be a multiple of 0x200000.
1991 
1992           Don't change this unless you know what you are doing.
1993 
1994 config RANDOMIZE_MEMORY
1995         bool "Randomize the kernel memory sections"
1996         depends on X86_64
1997         depends on RANDOMIZE_BASE
1998         default RANDOMIZE_BASE
1999         ---help---
2000            Randomizes the base virtual address of kernel memory sections
2001            (physical memory mapping, vmalloc & vmemmap). This security feature
2002            makes exploits relying on predictable memory locations less reliable.
2003 
2004            The order of allocations remains unchanged. Entropy is generated in
2005            the same way as RANDOMIZE_BASE. Current implementation in the optimal
2006            configuration have in average 30,000 different possible virtual
2007            addresses for each memory section.
2008 
2009            If unsure, say N.
2010 
2011 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2012         hex "Physical memory mapping padding" if EXPERT
2013         depends on RANDOMIZE_MEMORY
2014         default "0xa" if MEMORY_HOTPLUG
2015         default "0x0"
2016         range 0x1 0x40 if MEMORY_HOTPLUG
2017         range 0x0 0x40
2018         ---help---
2019            Define the padding in terabytes added to the existing physical
2020            memory size during kernel memory randomization. It is useful
2021            for memory hotplug support but reduces the entropy available for
2022            address randomization.
2023 
2024            If unsure, leave at the default value.
2025 
2026 config HOTPLUG_CPU
2027         bool "Support for hot-pluggable CPUs"
2028         depends on SMP
2029         ---help---
2030           Say Y here to allow turning CPUs off and on. CPUs can be
2031           controlled through /sys/devices/system/cpu.
2032           ( Note: power management support will enable this option
2033             automatically on SMP systems. )
2034           Say N if you want to disable CPU hotplug.
2035 
2036 config BOOTPARAM_HOTPLUG_CPU0
2037         bool "Set default setting of cpu0_hotpluggable"
2038         default n
2039         depends on HOTPLUG_CPU
2040         ---help---
2041           Set whether default state of cpu0_hotpluggable is on or off.
2042 
2043           Say Y here to enable CPU0 hotplug by default. If this switch
2044           is turned on, there is no need to give cpu0_hotplug kernel
2045           parameter and the CPU0 hotplug feature is enabled by default.
2046 
2047           Please note: there are two known CPU0 dependencies if you want
2048           to enable the CPU0 hotplug feature either by this switch or by
2049           cpu0_hotplug kernel parameter.
2050 
2051           First, resume from hibernate or suspend always starts from CPU0.
2052           So hibernate and suspend are prevented if CPU0 is offline.
2053 
2054           Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2055           offline if any interrupt can not migrate out of CPU0. There may
2056           be other CPU0 dependencies.
2057 
2058           Please make sure the dependencies are under your control before
2059           you enable this feature.
2060 
2061           Say N if you don't want to enable CPU0 hotplug feature by default.
2062           You still can enable the CPU0 hotplug feature at boot by kernel
2063           parameter cpu0_hotplug.
2064 
2065 config DEBUG_HOTPLUG_CPU0
2066         def_bool n
2067         prompt "Debug CPU0 hotplug"
2068         depends on HOTPLUG_CPU
2069         ---help---
2070           Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2071           soon as possible and boots up userspace with CPU0 offlined. User
2072           can online CPU0 back after boot time.
2073 
2074           To debug CPU0 hotplug, you need to enable CPU0 offline/online
2075           feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2076           compilation or giving cpu0_hotplug kernel parameter at boot.
2077 
2078           If unsure, say N.
2079 
2080 config COMPAT_VDSO
2081         def_bool n
2082         prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2083         depends on X86_32 || IA32_EMULATION
2084         ---help---
2085           Certain buggy versions of glibc will crash if they are
2086           presented with a 32-bit vDSO that is not mapped at the address
2087           indicated in its segment table.
2088 
2089           The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2090           and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2091           49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2092           the only released version with the bug, but OpenSUSE 9
2093           contains a buggy "glibc 2.3.2".
2094 
2095           The symptom of the bug is that everything crashes on startup, saying:
2096           dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2097 
2098           Saying Y here changes the default value of the vdso32 boot
2099           option from 1 to 0, which turns off the 32-bit vDSO entirely.
2100           This works around the glibc bug but hurts performance.
2101 
2102           If unsure, say N: if you are compiling your own kernel, you
2103           are unlikely to be using a buggy version of glibc.
2104 
2105 choice
2106         prompt "vsyscall table for legacy applications"
2107         depends on X86_64
2108         default LEGACY_VSYSCALL_EMULATE
2109         help
2110           Legacy user code that does not know how to find the vDSO expects
2111           to be able to issue three syscalls by calling fixed addresses in
2112           kernel space. Since this location is not randomized with ASLR,
2113           it can be used to assist security vulnerability exploitation.
2114 
2115           This setting can be changed at boot time via the kernel command
2116           line parameter vsyscall=[native|emulate|none].
2117 
2118           On a system with recent enough glibc (2.14 or newer) and no
2119           static binaries, you can say None without a performance penalty
2120           to improve security.
2121 
2122           If unsure, select "Emulate".
2123 
2124         config LEGACY_VSYSCALL_NATIVE
2125                 bool "Native"
2126                 help
2127                   Actual executable code is located in the fixed vsyscall
2128                   address mapping, implementing time() efficiently. Since
2129                   this makes the mapping executable, it can be used during
2130                   security vulnerability exploitation (traditionally as
2131                   ROP gadgets). This configuration is not recommended.
2132 
2133         config LEGACY_VSYSCALL_EMULATE
2134                 bool "Emulate"
2135                 help
2136                   The kernel traps and emulates calls into the fixed
2137                   vsyscall address mapping. This makes the mapping
2138                   non-executable, but it still contains known contents,
2139                   which could be used in certain rare security vulnerability
2140                   exploits. This configuration is recommended when userspace
2141                   still uses the vsyscall area.
2142 
2143         config LEGACY_VSYSCALL_NONE
2144                 bool "None"
2145                 help
2146                   There will be no vsyscall mapping at all. This will
2147                   eliminate any risk of ASLR bypass due to the vsyscall
2148                   fixed address mapping. Attempts to use the vsyscalls
2149                   will be reported to dmesg, so that either old or
2150                   malicious userspace programs can be identified.
2151 
2152 endchoice
2153 
2154 config CMDLINE_BOOL
2155         bool "Built-in kernel command line"
2156         ---help---
2157           Allow for specifying boot arguments to the kernel at
2158           build time.  On some systems (e.g. embedded ones), it is
2159           necessary or convenient to provide some or all of the
2160           kernel boot arguments with the kernel itself (that is,
2161           to not rely on the boot loader to provide them.)
2162 
2163           To compile command line arguments into the kernel,
2164           set this option to 'Y', then fill in the
2165           boot arguments in CONFIG_CMDLINE.
2166 
2167           Systems with fully functional boot loaders (i.e. non-embedded)
2168           should leave this option set to 'N'.
2169 
2170 config CMDLINE
2171         string "Built-in kernel command string"
2172         depends on CMDLINE_BOOL
2173         default ""
2174         ---help---
2175           Enter arguments here that should be compiled into the kernel
2176           image and used at boot time.  If the boot loader provides a
2177           command line at boot time, it is appended to this string to
2178           form the full kernel command line, when the system boots.
2179 
2180           However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2181           change this behavior.
2182 
2183           In most cases, the command line (whether built-in or provided
2184           by the boot loader) should specify the device for the root
2185           file system.
2186 
2187 config CMDLINE_OVERRIDE
2188         bool "Built-in command line overrides boot loader arguments"
2189         depends on CMDLINE_BOOL
2190         ---help---
2191           Set this option to 'Y' to have the kernel ignore the boot loader
2192           command line, and use ONLY the built-in command line.
2193 
2194           This is used to work around broken boot loaders.  This should
2195           be set to 'N' under normal conditions.
2196 
2197 config MODIFY_LDT_SYSCALL
2198         bool "Enable the LDT (local descriptor table)" if EXPERT
2199         default y
2200         ---help---
2201           Linux can allow user programs to install a per-process x86
2202           Local Descriptor Table (LDT) using the modify_ldt(2) system
2203           call.  This is required to run 16-bit or segmented code such as
2204           DOSEMU or some Wine programs.  It is also used by some very old
2205           threading libraries.
2206 
2207           Enabling this feature adds a small amount of overhead to
2208           context switches and increases the low-level kernel attack
2209           surface.  Disabling it removes the modify_ldt(2) system call.
2210 
2211           Saying 'N' here may make sense for embedded or server kernels.
2212 
2213 source "kernel/livepatch/Kconfig"
2214 
2215 endmenu
2216 
2217 config ARCH_ENABLE_MEMORY_HOTPLUG
2218         def_bool y
2219         depends on X86_64 || (X86_32 && HIGHMEM)
2220 
2221 config ARCH_ENABLE_MEMORY_HOTREMOVE
2222         def_bool y
2223         depends on MEMORY_HOTPLUG
2224 
2225 config USE_PERCPU_NUMA_NODE_ID
2226         def_bool y
2227         depends on NUMA
2228 
2229 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2230         def_bool y
2231         depends on X86_64 || X86_PAE
2232 
2233 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2234         def_bool y
2235         depends on X86_64 && HUGETLB_PAGE && MIGRATION
2236 
2237 menu "Power management and ACPI options"
2238 
2239 config ARCH_HIBERNATION_HEADER
2240         def_bool y
2241         depends on X86_64 && HIBERNATION
2242 
2243 source "kernel/power/Kconfig"
2244 
2245 source "drivers/acpi/Kconfig"
2246 
2247 source "drivers/sfi/Kconfig"
2248 
2249 config X86_APM_BOOT
2250         def_bool y
2251         depends on APM
2252 
2253 menuconfig APM
2254         tristate "APM (Advanced Power Management) BIOS support"
2255         depends on X86_32 && PM_SLEEP
2256         ---help---
2257           APM is a BIOS specification for saving power using several different
2258           techniques. This is mostly useful for battery powered laptops with
2259           APM compliant BIOSes. If you say Y here, the system time will be
2260           reset after a RESUME operation, the /proc/apm device will provide
2261           battery status information, and user-space programs will receive
2262           notification of APM "events" (e.g. battery status change).
2263 
2264           If you select "Y" here, you can disable actual use of the APM
2265           BIOS by passing the "apm=off" option to the kernel at boot time.
2266 
2267           Note that the APM support is almost completely disabled for
2268           machines with more than one CPU.
2269 
2270           In order to use APM, you will need supporting software. For location
2271           and more information, read <file:Documentation/power/apm-acpi.txt>
2272           and the Battery Powered Linux mini-HOWTO, available from
2273           <http://www.tldp.org/docs.html#howto>.
2274 
2275           This driver does not spin down disk drives (see the hdparm(8)
2276           manpage ("man 8 hdparm") for that), and it doesn't turn off
2277           VESA-compliant "green" monitors.
2278 
2279           This driver does not support the TI 4000M TravelMate and the ACER
2280           486/DX4/75 because they don't have compliant BIOSes. Many "green"
2281           desktop machines also don't have compliant BIOSes, and this driver
2282           may cause those machines to panic during the boot phase.
2283 
2284           Generally, if you don't have a battery in your machine, there isn't
2285           much point in using this driver and you should say N. If you get
2286           random kernel OOPSes or reboots that don't seem to be related to
2287           anything, try disabling/enabling this option (or disabling/enabling
2288           APM in your BIOS).
2289 
2290           Some other things you should try when experiencing seemingly random,
2291           "weird" problems:
2292 
2293           1) make sure that you have enough swap space and that it is
2294           enabled.
2295           2) pass the "no-hlt" option to the kernel
2296           3) switch on floating point emulation in the kernel and pass
2297           the "no387" option to the kernel
2298           4) pass the "floppy=nodma" option to the kernel
2299           5) pass the "mem=4M" option to the kernel (thereby disabling
2300           all but the first 4 MB of RAM)
2301           6) make sure that the CPU is not over clocked.
2302           7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2303           8) disable the cache from your BIOS settings
2304           9) install a fan for the video card or exchange video RAM
2305           10) install a better fan for the CPU
2306           11) exchange RAM chips
2307           12) exchange the motherboard.
2308 
2309           To compile this driver as a module, choose M here: the
2310           module will be called apm.
2311 
2312 if APM
2313 
2314 config APM_IGNORE_USER_SUSPEND
2315         bool "Ignore USER SUSPEND"
2316         ---help---
2317           This option will ignore USER SUSPEND requests. On machines with a
2318           compliant APM BIOS, you want to say N. However, on the NEC Versa M
2319           series notebooks, it is necessary to say Y because of a BIOS bug.
2320 
2321 config APM_DO_ENABLE
2322         bool "Enable PM at boot time"
2323         ---help---
2324           Enable APM features at boot time. From page 36 of the APM BIOS
2325           specification: "When disabled, the APM BIOS does not automatically
2326           power manage devices, enter the Standby State, enter the Suspend
2327           State, or take power saving steps in response to CPU Idle calls."
2328           This driver will make CPU Idle calls when Linux is idle (unless this
2329           feature is turned off -- see "Do CPU IDLE calls", below). This
2330           should always save battery power, but more complicated APM features
2331           will be dependent on your BIOS implementation. You may need to turn
2332           this option off if your computer hangs at boot time when using APM
2333           support, or if it beeps continuously instead of suspending. Turn
2334           this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2335           T400CDT. This is off by default since most machines do fine without
2336           this feature.
2337 
2338 config APM_CPU_IDLE
2339         depends on CPU_IDLE
2340         bool "Make CPU Idle calls when idle"
2341         ---help---
2342           Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2343           On some machines, this can activate improved power savings, such as
2344           a slowed CPU clock rate, when the machine is idle. These idle calls
2345           are made after the idle loop has run for some length of time (e.g.,
2346           333 mS). On some machines, this will cause a hang at boot time or
2347           whenever the CPU becomes idle. (On machines with more than one CPU,
2348           this option does nothing.)
2349 
2350 config APM_DISPLAY_BLANK
2351         bool "Enable console blanking using APM"
2352         ---help---
2353           Enable console blanking using the APM. Some laptops can use this to
2354           turn off the LCD backlight when the screen blanker of the Linux
2355           virtual console blanks the screen. Note that this is only used by
2356           the virtual console screen blanker, and won't turn off the backlight
2357           when using the X Window system. This also doesn't have anything to
2358           do with your VESA-compliant power-saving monitor. Further, this
2359           option doesn't work for all laptops -- it might not turn off your
2360           backlight at all, or it might print a lot of errors to the console,
2361           especially if you are using gpm.
2362 
2363 config APM_ALLOW_INTS
2364         bool "Allow interrupts during APM BIOS calls"
2365         ---help---
2366           Normally we disable external interrupts while we are making calls to
2367           the APM BIOS as a measure to lessen the effects of a badly behaving
2368           BIOS implementation.  The BIOS should reenable interrupts if it
2369           needs to.  Unfortunately, some BIOSes do not -- especially those in
2370           many of the newer IBM Thinkpads.  If you experience hangs when you
2371           suspend, try setting this to Y.  Otherwise, say N.
2372 
2373 endif # APM
2374 
2375 source "drivers/cpufreq/Kconfig"
2376 
2377 source "drivers/cpuidle/Kconfig"
2378 
2379 source "drivers/idle/Kconfig"
2380 
2381 endmenu
2382 
2383 
2384 menu "Bus options (PCI etc.)"
2385 
2386 config PCI
2387         bool "PCI support"
2388         default y
2389         ---help---
2390           Find out whether you have a PCI motherboard. PCI is the name of a
2391           bus system, i.e. the way the CPU talks to the other stuff inside
2392           your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2393           VESA. If you have PCI, say Y, otherwise N.
2394 
2395 choice
2396         prompt "PCI access mode"
2397         depends on X86_32 && PCI
2398         default PCI_GOANY
2399         ---help---
2400           On PCI systems, the BIOS can be used to detect the PCI devices and
2401           determine their configuration. However, some old PCI motherboards
2402           have BIOS bugs and may crash if this is done. Also, some embedded
2403           PCI-based systems don't have any BIOS at all. Linux can also try to
2404           detect the PCI hardware directly without using the BIOS.
2405 
2406           With this option, you can specify how Linux should detect the
2407           PCI devices. If you choose "BIOS", the BIOS will be used,
2408           if you choose "Direct", the BIOS won't be used, and if you
2409           choose "MMConfig", then PCI Express MMCONFIG will be used.
2410           If you choose "Any", the kernel will try MMCONFIG, then the
2411           direct access method and falls back to the BIOS if that doesn't
2412           work. If unsure, go with the default, which is "Any".
2413 
2414 config PCI_GOBIOS
2415         bool "BIOS"
2416 
2417 config PCI_GOMMCONFIG
2418         bool "MMConfig"
2419 
2420 config PCI_GODIRECT
2421         bool "Direct"
2422 
2423 config PCI_GOOLPC
2424         bool "OLPC XO-1"
2425         depends on OLPC
2426 
2427 config PCI_GOANY
2428         bool "Any"
2429 
2430 endchoice
2431 
2432 config PCI_BIOS
2433         def_bool y
2434         depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2435 
2436 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2437 config PCI_DIRECT
2438         def_bool y
2439         depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2440 
2441 config PCI_MMCONFIG
2442         def_bool y
2443         depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2444 
2445 config PCI_OLPC
2446         def_bool y
2447         depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2448 
2449 config PCI_XEN
2450         def_bool y
2451         depends on PCI && XEN
2452         select SWIOTLB_XEN
2453 
2454 config PCI_DOMAINS
2455         def_bool y
2456         depends on PCI
2457 
2458 config PCI_MMCONFIG
2459         bool "Support mmconfig PCI config space access"
2460         depends on X86_64 && PCI && ACPI
2461 
2462 config PCI_CNB20LE_QUIRK
2463         bool "Read CNB20LE Host Bridge Windows" if EXPERT
2464         depends on PCI
2465         help
2466           Read the PCI windows out of the CNB20LE host bridge. This allows
2467           PCI hotplug to work on systems with the CNB20LE chipset which do
2468           not have ACPI.
2469 
2470           There's no public spec for this chipset, and this functionality
2471           is known to be incomplete.
2472 
2473           You should say N unless you know you need this.
2474 
2475 source "drivers/pci/Kconfig"
2476 
2477 config ISA_BUS
2478         bool "ISA-style bus support on modern systems" if EXPERT
2479         select ISA_BUS_API
2480         help
2481           Enables ISA-style drivers on modern systems. This is necessary to
2482           support PC/104 devices on X86_64 platforms.
2483 
2484           If unsure, say N.
2485 
2486 # x86_64 have no ISA slots, but can have ISA-style DMA.
2487 config ISA_DMA_API
2488         bool "ISA-style DMA support" if (X86_64 && EXPERT)
2489         default y
2490         help
2491           Enables ISA-style DMA support for devices requiring such controllers.
2492           If unsure, say Y.
2493 
2494 if X86_32
2495 
2496 config ISA
2497         bool "ISA support"
2498         ---help---
2499           Find out whether you have ISA slots on your motherboard.  ISA is the
2500           name of a bus system, i.e. the way the CPU talks to the other stuff
2501           inside your box.  Other bus systems are PCI, EISA, MicroChannel
2502           (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2503           newer boards don't support it.  If you have ISA, say Y, otherwise N.
2504 
2505 config EISA
2506         bool "EISA support"
2507         depends on ISA
2508         ---help---
2509           The Extended Industry Standard Architecture (EISA) bus was
2510           developed as an open alternative to the IBM MicroChannel bus.
2511 
2512           The EISA bus provided some of the features of the IBM MicroChannel
2513           bus while maintaining backward compatibility with cards made for
2514           the older ISA bus.  The EISA bus saw limited use between 1988 and
2515           1995 when it was made obsolete by the PCI bus.
2516 
2517           Say Y here if you are building a kernel for an EISA-based machine.
2518 
2519           Otherwise, say N.
2520 
2521 source "drivers/eisa/Kconfig"
2522 
2523 config SCx200
2524         tristate "NatSemi SCx200 support"
2525         ---help---
2526           This provides basic support for National Semiconductor's
2527           (now AMD's) Geode processors.  The driver probes for the
2528           PCI-IDs of several on-chip devices, so its a good dependency
2529           for other scx200_* drivers.
2530 
2531           If compiled as a module, the driver is named scx200.
2532 
2533 config SCx200HR_TIMER
2534         tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2535         depends on SCx200
2536         default y
2537         ---help---
2538           This driver provides a clocksource built upon the on-chip
2539           27MHz high-resolution timer.  Its also a workaround for
2540           NSC Geode SC-1100's buggy TSC, which loses time when the
2541           processor goes idle (as is done by the scheduler).  The
2542           other workaround is idle=poll boot option.
2543 
2544 config OLPC
2545         bool "One Laptop Per Child support"
2546         depends on !X86_PAE
2547         select GPIOLIB
2548         select OF
2549         select OF_PROMTREE
2550         select IRQ_DOMAIN
2551         ---help---
2552           Add support for detecting the unique features of the OLPC
2553           XO hardware.
2554 
2555 config OLPC_XO1_PM
2556         bool "OLPC XO-1 Power Management"
2557         depends on OLPC && MFD_CS5535 && PM_SLEEP
2558         select MFD_CORE
2559         ---help---
2560           Add support for poweroff and suspend of the OLPC XO-1 laptop.
2561 
2562 config OLPC_XO1_RTC
2563         bool "OLPC XO-1 Real Time Clock"
2564         depends on OLPC_XO1_PM && RTC_DRV_CMOS
2565         ---help---
2566           Add support for the XO-1 real time clock, which can be used as a
2567           programmable wakeup source.
2568 
2569 config OLPC_XO1_SCI
2570         bool "OLPC XO-1 SCI extras"
2571         depends on OLPC && OLPC_XO1_PM
2572         depends on INPUT=y
2573         select POWER_SUPPLY
2574         select GPIO_CS5535
2575         select MFD_CORE
2576         ---help---
2577           Add support for SCI-based features of the OLPC XO-1 laptop:
2578            - EC-driven system wakeups
2579            - Power button
2580            - Ebook switch
2581            - Lid switch
2582            - AC adapter status updates
2583            - Battery status updates
2584 
2585 config OLPC_XO15_SCI
2586         bool "OLPC XO-1.5 SCI extras"
2587         depends on OLPC && ACPI
2588         select POWER_SUPPLY
2589         ---help---
2590           Add support for SCI-based features of the OLPC XO-1.5 laptop:
2591            - EC-driven system wakeups
2592            - AC adapter status updates
2593            - Battery status updates
2594 
2595 config ALIX
2596         bool "PCEngines ALIX System Support (LED setup)"
2597         select GPIOLIB
2598         ---help---
2599           This option enables system support for the PCEngines ALIX.
2600           At present this just sets up LEDs for GPIO control on
2601           ALIX2/3/6 boards.  However, other system specific setup should
2602           get added here.
2603 
2604           Note: You must still enable the drivers for GPIO and LED support
2605           (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2606 
2607           Note: You have to set alix.force=1 for boards with Award BIOS.
2608 
2609 config NET5501
2610         bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2611         select GPIOLIB
2612         ---help---
2613           This option enables system support for the Soekris Engineering net5501.
2614 
2615 config GEOS
2616         bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2617         select GPIOLIB
2618         depends on DMI
2619         ---help---
2620           This option enables system support for the Traverse Technologies GEOS.
2621 
2622 config TS5500
2623         bool "Technologic Systems TS-5500 platform support"
2624         depends on MELAN
2625         select CHECK_SIGNATURE
2626         select NEW_LEDS
2627         select LEDS_CLASS
2628         ---help---
2629           This option enables system support for the Technologic Systems TS-5500.
2630 
2631 endif # X86_32
2632 
2633 config AMD_NB
2634         def_bool y
2635         depends on CPU_SUP_AMD && PCI
2636 
2637 source "drivers/pcmcia/Kconfig"
2638 
2639 config RAPIDIO
2640         tristate "RapidIO support"
2641         depends on PCI
2642         default n
2643         help
2644           If enabled this option will include drivers and the core
2645           infrastructure code to support RapidIO interconnect devices.
2646 
2647 source "drivers/rapidio/Kconfig"
2648 
2649 config X86_SYSFB
2650         bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2651         help
2652           Firmwares often provide initial graphics framebuffers so the BIOS,
2653           bootloader or kernel can show basic video-output during boot for
2654           user-guidance and debugging. Historically, x86 used the VESA BIOS
2655           Extensions and EFI-framebuffers for this, which are mostly limited
2656           to x86.
2657           This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2658           framebuffers so the new generic system-framebuffer drivers can be
2659           used on x86. If the framebuffer is not compatible with the generic
2660           modes, it is adverticed as fallback platform framebuffer so legacy
2661           drivers like efifb, vesafb and uvesafb can pick it up.
2662           If this option is not selected, all system framebuffers are always
2663           marked as fallback platform framebuffers as usual.
2664 
2665           Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2666           not be able to pick up generic system framebuffers if this option
2667           is selected. You are highly encouraged to enable simplefb as
2668           replacement if you select this option. simplefb can correctly deal
2669           with generic system framebuffers. But you should still keep vesafb
2670           and others enabled as fallback if a system framebuffer is
2671           incompatible with simplefb.
2672 
2673           If unsure, say Y.
2674 
2675 endmenu
2676 
2677 
2678 menu "Executable file formats / Emulations"
2679 
2680 source "fs/Kconfig.binfmt"
2681 
2682 config IA32_EMULATION
2683         bool "IA32 Emulation"
2684         depends on X86_64
2685         select BINFMT_ELF
2686         select COMPAT_BINFMT_ELF
2687         select ARCH_WANT_OLD_COMPAT_IPC
2688         ---help---
2689           Include code to run legacy 32-bit programs under a
2690           64-bit kernel. You should likely turn this on, unless you're
2691           100% sure that you don't have any 32-bit programs left.
2692 
2693 config IA32_AOUT
2694         tristate "IA32 a.out support"
2695         depends on IA32_EMULATION
2696         ---help---
2697           Support old a.out binaries in the 32bit emulation.
2698 
2699 config X86_X32
2700         bool "x32 ABI for 64-bit mode"
2701         depends on X86_64
2702         ---help---
2703           Include code to run binaries for the x32 native 32-bit ABI
2704           for 64-bit processors.  An x32 process gets access to the
2705           full 64-bit register file and wide data path while leaving
2706           pointers at 32 bits for smaller memory footprint.
2707 
2708           You will need a recent binutils (2.22 or later) with
2709           elf32_x86_64 support enabled to compile a kernel with this
2710           option set.
2711 
2712 config COMPAT
2713         def_bool y
2714         depends on IA32_EMULATION || X86_X32
2715 
2716 if COMPAT
2717 config COMPAT_FOR_U64_ALIGNMENT
2718         def_bool y
2719 
2720 config SYSVIPC_COMPAT
2721         def_bool y
2722         depends on SYSVIPC
2723 
2724 config KEYS_COMPAT
2725         def_bool y
2726         depends on KEYS
2727 endif
2728 
2729 endmenu
2730 
2731 
2732 config HAVE_ATOMIC_IOMAP
2733         def_bool y
2734         depends on X86_32
2735 
2736 config X86_DEV_DMA_OPS
2737         bool
2738         depends on X86_64 || STA2X11
2739 
2740 config X86_DMA_REMAP
2741         bool
2742         depends on STA2X11
2743 
2744 config PMC_ATOM
2745         def_bool y
2746         depends on PCI
2747 
2748 config VMD
2749         depends on PCI_MSI
2750         tristate "Volume Management Device Driver"
2751         default N
2752         ---help---
2753           Adds support for the Intel Volume Management Device (VMD). VMD is a
2754           secondary PCI host bridge that allows PCI Express root ports,
2755           and devices attached to them, to be removed from the default
2756           PCI domain and placed within the VMD domain. This provides
2757           more bus resources than are otherwise possible with a
2758           single domain. If you know your system provides one of these and
2759           has devices attached to it, say Y; if you are not sure, say N.
2760 
2761 source "net/Kconfig"
2762 
2763 source "drivers/Kconfig"
2764 
2765 source "drivers/firmware/Kconfig"
2766 
2767 source "fs/Kconfig"
2768 
2769 source "arch/x86/Kconfig.debug"
2770 
2771 source "security/Kconfig"
2772 
2773 source "crypto/Kconfig"
2774 
2775 source "arch/x86/kvm/Kconfig"
2776 
2777 source "lib/Kconfig"

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