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Linux/arch/x86/Kconfig

  1 # Select 32 or 64 bit
  2 config 64BIT
  3         bool "64-bit kernel" if ARCH = "x86"
  4         default ARCH != "i386"
  5         ---help---
  6           Say yes to build a 64-bit kernel - formerly known as x86_64
  7           Say no to build a 32-bit kernel - formerly known as i386
  8 
  9 config X86_32
 10         def_bool y
 11         depends on !64BIT
 12 
 13 config X86_64
 14         def_bool y
 15         depends on 64BIT
 16 
 17 ### Arch settings
 18 config X86
 19         def_bool y
 20         select ACPI_LEGACY_TABLES_LOOKUP        if ACPI
 21         select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
 22         select ANON_INODES
 23         select ARCH_CLOCKSOURCE_DATA
 24         select ARCH_DISCARD_MEMBLOCK
 25         select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 26         select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
 27         select ARCH_HAS_ELF_RANDOMIZE
 28         select ARCH_HAS_FAST_MULTIPLIER
 29         select ARCH_HAS_GCOV_PROFILE_ALL
 30         select ARCH_HAS_PMEM_API                if X86_64
 31         select ARCH_HAS_MMIO_FLUSH
 32         select ARCH_HAS_SG_CHAIN
 33         select ARCH_HAVE_NMI_SAFE_CMPXCHG
 34         select ARCH_MIGHT_HAVE_ACPI_PDC         if ACPI
 35         select ARCH_MIGHT_HAVE_PC_PARPORT
 36         select ARCH_MIGHT_HAVE_PC_SERIO
 37         select ARCH_SUPPORTS_ATOMIC_RMW
 38         select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
 39         select ARCH_SUPPORTS_INT128             if X86_64
 40         select ARCH_SUPPORTS_NUMA_BALANCING     if X86_64
 41         select ARCH_USE_BUILTIN_BSWAP
 42         select ARCH_USE_CMPXCHG_LOCKREF         if X86_64
 43         select ARCH_USE_QUEUED_RWLOCKS
 44         select ARCH_USE_QUEUED_SPINLOCKS
 45         select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
 46         select ARCH_WANTS_DYNAMIC_TASK_STRUCT
 47         select ARCH_WANT_FRAME_POINTERS
 48         select ARCH_WANT_IPC_PARSE_VERSION      if X86_32
 49         select ARCH_WANT_OPTIONAL_GPIOLIB
 50         select BUILDTIME_EXTABLE_SORT
 51         select CLKEVT_I8253
 52         select CLKSRC_I8253                     if X86_32
 53         select CLOCKSOURCE_VALIDATE_LAST_CYCLE
 54         select CLOCKSOURCE_WATCHDOG
 55         select CLONE_BACKWARDS                  if X86_32
 56         select COMPAT_OLD_SIGACTION             if IA32_EMULATION
 57         select DCACHE_WORD_ACCESS
 58         select EDAC_ATOMIC_SCRUB
 59         select EDAC_SUPPORT
 60         select GENERIC_CLOCKEVENTS
 61         select GENERIC_CLOCKEVENTS_BROADCAST    if X86_64 || (X86_32 && X86_LOCAL_APIC)
 62         select GENERIC_CLOCKEVENTS_MIN_ADJUST
 63         select GENERIC_CMOS_UPDATE
 64         select GENERIC_CPU_AUTOPROBE
 65         select GENERIC_EARLY_IOREMAP
 66         select GENERIC_FIND_FIRST_BIT
 67         select GENERIC_IOMAP
 68         select GENERIC_IRQ_PROBE
 69         select GENERIC_IRQ_SHOW
 70         select GENERIC_PENDING_IRQ              if SMP
 71         select GENERIC_SMP_IDLE_THREAD
 72         select GENERIC_STRNCPY_FROM_USER
 73         select GENERIC_STRNLEN_USER
 74         select GENERIC_TIME_VSYSCALL
 75         select HAVE_ACPI_APEI                   if ACPI
 76         select HAVE_ACPI_APEI_NMI               if ACPI
 77         select HAVE_ALIGNED_STRUCT_PAGE         if SLUB
 78         select HAVE_AOUT                        if X86_32
 79         select HAVE_ARCH_AUDITSYSCALL
 80         select HAVE_ARCH_HUGE_VMAP              if X86_64 || X86_PAE
 81         select HAVE_ARCH_JUMP_LABEL
 82         select HAVE_ARCH_KASAN                  if X86_64 && SPARSEMEM_VMEMMAP
 83         select HAVE_ARCH_KGDB
 84         select HAVE_ARCH_KMEMCHECK
 85         select HAVE_ARCH_SECCOMP_FILTER
 86         select HAVE_ARCH_SOFT_DIRTY             if X86_64
 87         select HAVE_ARCH_TRACEHOOK
 88         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 89         select HAVE_BPF_JIT                     if X86_64
 90         select HAVE_CC_STACKPROTECTOR
 91         select HAVE_CMPXCHG_DOUBLE
 92         select HAVE_CMPXCHG_LOCAL
 93         select HAVE_CONTEXT_TRACKING            if X86_64
 94         select HAVE_COPY_THREAD_TLS
 95         select HAVE_C_RECORDMCOUNT
 96         select HAVE_DEBUG_KMEMLEAK
 97         select HAVE_DEBUG_STACKOVERFLOW
 98         select HAVE_DMA_API_DEBUG
 99         select HAVE_DMA_ATTRS
100         select HAVE_DMA_CONTIGUOUS
101         select HAVE_DYNAMIC_FTRACE
102         select HAVE_DYNAMIC_FTRACE_WITH_REGS
103         select HAVE_EFFICIENT_UNALIGNED_ACCESS
104         select HAVE_FENTRY                      if X86_64
105         select HAVE_FTRACE_MCOUNT_RECORD
106         select HAVE_FUNCTION_GRAPH_FP_TEST
107         select HAVE_FUNCTION_GRAPH_TRACER
108         select HAVE_FUNCTION_TRACER
109         select HAVE_GENERIC_DMA_COHERENT        if X86_32
110         select HAVE_HW_BREAKPOINT
111         select HAVE_IDE
112         select HAVE_IOREMAP_PROT
113         select HAVE_IRQ_EXIT_ON_IRQ_STACK       if X86_64
114         select HAVE_IRQ_TIME_ACCOUNTING
115         select HAVE_KERNEL_BZIP2
116         select HAVE_KERNEL_GZIP
117         select HAVE_KERNEL_LZ4
118         select HAVE_KERNEL_LZMA
119         select HAVE_KERNEL_LZO
120         select HAVE_KERNEL_XZ
121         select HAVE_KPROBES
122         select HAVE_KPROBES_ON_FTRACE
123         select HAVE_KRETPROBES
124         select HAVE_KVM
125         select HAVE_LIVEPATCH                   if X86_64
126         select HAVE_MEMBLOCK
127         select HAVE_MEMBLOCK_NODE_MAP
128         select HAVE_MIXED_BREAKPOINTS_REGS
129         select HAVE_OPROFILE
130         select HAVE_OPTPROBES
131         select HAVE_PCSPKR_PLATFORM
132         select HAVE_PERF_EVENTS
133         select HAVE_PERF_EVENTS_NMI
134         select HAVE_PERF_REGS
135         select HAVE_PERF_USER_STACK_DUMP
136         select HAVE_REGS_AND_STACK_ACCESS_API
137         select HAVE_SYSCALL_TRACEPOINTS
138         select HAVE_UID16                       if X86_32 || IA32_EMULATION
139         select HAVE_UNSTABLE_SCHED_CLOCK
140         select HAVE_USER_RETURN_NOTIFIER
141         select IRQ_FORCED_THREADING
142         select MODULES_USE_ELF_RELA             if X86_64
143         select MODULES_USE_ELF_REL              if X86_32
144         select OLD_SIGACTION                    if X86_32
145         select OLD_SIGSUSPEND3                  if X86_32 || IA32_EMULATION
146         select PERF_EVENTS
147         select RTC_LIB
148         select SPARSE_IRQ
149         select SRCU
150         select SYSCTL_EXCEPTION_TRACE
151         select USER_STACKTRACE_SUPPORT
152         select VIRT_TO_BUS
153         select X86_DEV_DMA_OPS                  if X86_64
154         select X86_FEATURE_NAMES                if PROC_FS
155 
156 config INSTRUCTION_DECODER
157         def_bool y
158         depends on KPROBES || PERF_EVENTS || UPROBES
159 
160 config PERF_EVENTS_INTEL_UNCORE
161         def_bool y
162         depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
163 
164 config OUTPUT_FORMAT
165         string
166         default "elf32-i386" if X86_32
167         default "elf64-x86-64" if X86_64
168 
169 config ARCH_DEFCONFIG
170         string
171         default "arch/x86/configs/i386_defconfig" if X86_32
172         default "arch/x86/configs/x86_64_defconfig" if X86_64
173 
174 config LOCKDEP_SUPPORT
175         def_bool y
176 
177 config STACKTRACE_SUPPORT
178         def_bool y
179 
180 config HAVE_LATENCYTOP_SUPPORT
181         def_bool y
182 
183 config MMU
184         def_bool y
185 
186 config SBUS
187         bool
188 
189 config NEED_DMA_MAP_STATE
190         def_bool y
191         depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
192 
193 config NEED_SG_DMA_LENGTH
194         def_bool y
195 
196 config GENERIC_ISA_DMA
197         def_bool y
198         depends on ISA_DMA_API
199 
200 config GENERIC_BUG
201         def_bool y
202         depends on BUG
203         select GENERIC_BUG_RELATIVE_POINTERS if X86_64
204 
205 config GENERIC_BUG_RELATIVE_POINTERS
206         bool
207 
208 config GENERIC_HWEIGHT
209         def_bool y
210 
211 config ARCH_MAY_HAVE_PC_FDC
212         def_bool y
213         depends on ISA_DMA_API
214 
215 config RWSEM_XCHGADD_ALGORITHM
216         def_bool y
217 
218 config GENERIC_CALIBRATE_DELAY
219         def_bool y
220 
221 config ARCH_HAS_CPU_RELAX
222         def_bool y
223 
224 config ARCH_HAS_CACHE_LINE_SIZE
225         def_bool y
226 
227 config HAVE_SETUP_PER_CPU_AREA
228         def_bool y
229 
230 config NEED_PER_CPU_EMBED_FIRST_CHUNK
231         def_bool y
232 
233 config NEED_PER_CPU_PAGE_FIRST_CHUNK
234         def_bool y
235 
236 config ARCH_HIBERNATION_POSSIBLE
237         def_bool y
238 
239 config ARCH_SUSPEND_POSSIBLE
240         def_bool y
241 
242 config ARCH_WANT_HUGE_PMD_SHARE
243         def_bool y
244 
245 config ARCH_WANT_GENERAL_HUGETLB
246         def_bool y
247 
248 config ZONE_DMA32
249         def_bool y if X86_64
250 
251 config AUDIT_ARCH
252         def_bool y if X86_64
253 
254 config ARCH_SUPPORTS_OPTIMIZED_INLINING
255         def_bool y
256 
257 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
258         def_bool y
259 
260 config KASAN_SHADOW_OFFSET
261         hex
262         depends on KASAN
263         default 0xdffffc0000000000
264 
265 config HAVE_INTEL_TXT
266         def_bool y
267         depends on INTEL_IOMMU && ACPI
268 
269 config X86_32_SMP
270         def_bool y
271         depends on X86_32 && SMP
272 
273 config X86_64_SMP
274         def_bool y
275         depends on X86_64 && SMP
276 
277 config X86_32_LAZY_GS
278         def_bool y
279         depends on X86_32 && !CC_STACKPROTECTOR
280 
281 config ARCH_HWEIGHT_CFLAGS
282         string
283         default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
284         default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
285 
286 config ARCH_SUPPORTS_UPROBES
287         def_bool y
288 
289 config FIX_EARLYCON_MEM
290         def_bool y
291 
292 config PGTABLE_LEVELS
293         int
294         default 4 if X86_64
295         default 3 if X86_PAE
296         default 2
297 
298 source "init/Kconfig"
299 source "kernel/Kconfig.freezer"
300 
301 menu "Processor type and features"
302 
303 config ZONE_DMA
304         bool "DMA memory allocation support" if EXPERT
305         default y
306         help
307           DMA memory allocation support allows devices with less than 32-bit
308           addressing to allocate within the first 16MB of address space.
309           Disable if no such devices will be used.
310 
311           If unsure, say Y.
312 
313 config SMP
314         bool "Symmetric multi-processing support"
315         ---help---
316           This enables support for systems with more than one CPU. If you have
317           a system with only one CPU, say N. If you have a system with more
318           than one CPU, say Y.
319 
320           If you say N here, the kernel will run on uni- and multiprocessor
321           machines, but will use only one CPU of a multiprocessor machine. If
322           you say Y here, the kernel will run on many, but not all,
323           uniprocessor machines. On a uniprocessor machine, the kernel
324           will run faster if you say N here.
325 
326           Note that if you say Y here and choose architecture "586" or
327           "Pentium" under "Processor family", the kernel will not work on 486
328           architectures. Similarly, multiprocessor kernels for the "PPro"
329           architecture may not work on all Pentium based boards.
330 
331           People using multiprocessor machines who say Y here should also say
332           Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
333           Management" code will be disabled if you say Y here.
334 
335           See also <file:Documentation/x86/i386/IO-APIC.txt>,
336           <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
337           <http://www.tldp.org/docs.html#howto>.
338 
339           If you don't know what to do here, say N.
340 
341 config X86_FEATURE_NAMES
342         bool "Processor feature human-readable names" if EMBEDDED
343         default y
344         ---help---
345           This option compiles in a table of x86 feature bits and corresponding
346           names.  This is required to support /proc/cpuinfo and a few kernel
347           messages.  You can disable this to save space, at the expense of
348           making those few kernel messages show numeric feature bits instead.
349 
350           If in doubt, say Y.
351 
352 config X86_X2APIC
353         bool "Support x2apic"
354         depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
355         ---help---
356           This enables x2apic support on CPUs that have this feature.
357 
358           This allows 32-bit apic IDs (so it can support very large systems),
359           and accesses the local apic via MSRs not via mmio.
360 
361           If you don't know what to do here, say N.
362 
363 config X86_MPPARSE
364         bool "Enable MPS table" if ACPI || SFI
365         default y
366         depends on X86_LOCAL_APIC
367         ---help---
368           For old smp systems that do not have proper acpi support. Newer systems
369           (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
370 
371 config X86_BIGSMP
372         bool "Support for big SMP systems with more than 8 CPUs"
373         depends on X86_32 && SMP
374         ---help---
375           This option is needed for the systems that have more than 8 CPUs
376 
377 config GOLDFISH
378        def_bool y
379        depends on X86_GOLDFISH
380 
381 if X86_32
382 config X86_EXTENDED_PLATFORM
383         bool "Support for extended (non-PC) x86 platforms"
384         default y
385         ---help---
386           If you disable this option then the kernel will only support
387           standard PC platforms. (which covers the vast majority of
388           systems out there.)
389 
390           If you enable this option then you'll be able to select support
391           for the following (non-PC) 32 bit x86 platforms:
392                 Goldfish (Android emulator)
393                 AMD Elan
394                 RDC R-321x SoC
395                 SGI 320/540 (Visual Workstation)
396                 STA2X11-based (e.g. Northville)
397                 Moorestown MID devices
398 
399           If you have one of these systems, or if you want to build a
400           generic distribution kernel, say Y here - otherwise say N.
401 endif
402 
403 if X86_64
404 config X86_EXTENDED_PLATFORM
405         bool "Support for extended (non-PC) x86 platforms"
406         default y
407         ---help---
408           If you disable this option then the kernel will only support
409           standard PC platforms. (which covers the vast majority of
410           systems out there.)
411 
412           If you enable this option then you'll be able to select support
413           for the following (non-PC) 64 bit x86 platforms:
414                 Numascale NumaChip
415                 ScaleMP vSMP
416                 SGI Ultraviolet
417 
418           If you have one of these systems, or if you want to build a
419           generic distribution kernel, say Y here - otherwise say N.
420 endif
421 # This is an alphabetically sorted list of 64 bit extended platforms
422 # Please maintain the alphabetic order if and when there are additions
423 config X86_NUMACHIP
424         bool "Numascale NumaChip"
425         depends on X86_64
426         depends on X86_EXTENDED_PLATFORM
427         depends on NUMA
428         depends on SMP
429         depends on X86_X2APIC
430         depends on PCI_MMCONFIG
431         ---help---
432           Adds support for Numascale NumaChip large-SMP systems. Needed to
433           enable more than ~168 cores.
434           If you don't have one of these, you should say N here.
435 
436 config X86_VSMP
437         bool "ScaleMP vSMP"
438         select HYPERVISOR_GUEST
439         select PARAVIRT
440         depends on X86_64 && PCI
441         depends on X86_EXTENDED_PLATFORM
442         depends on SMP
443         ---help---
444           Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
445           supposed to run on these EM64T-based machines.  Only choose this option
446           if you have one of these machines.
447 
448 config X86_UV
449         bool "SGI Ultraviolet"
450         depends on X86_64
451         depends on X86_EXTENDED_PLATFORM
452         depends on NUMA
453         depends on X86_X2APIC
454         depends on PCI
455         ---help---
456           This option is needed in order to support SGI Ultraviolet systems.
457           If you don't have one of these, you should say N here.
458 
459 # Following is an alphabetically sorted list of 32 bit extended platforms
460 # Please maintain the alphabetic order if and when there are additions
461 
462 config X86_GOLDFISH
463        bool "Goldfish (Virtual Platform)"
464        depends on X86_EXTENDED_PLATFORM
465        ---help---
466          Enable support for the Goldfish virtual platform used primarily
467          for Android development. Unless you are building for the Android
468          Goldfish emulator say N here.
469 
470 config X86_INTEL_CE
471         bool "CE4100 TV platform"
472         depends on PCI
473         depends on PCI_GODIRECT
474         depends on X86_IO_APIC
475         depends on X86_32
476         depends on X86_EXTENDED_PLATFORM
477         select X86_REBOOTFIXUPS
478         select OF
479         select OF_EARLY_FLATTREE
480         ---help---
481           Select for the Intel CE media processor (CE4100) SOC.
482           This option compiles in support for the CE4100 SOC for settop
483           boxes and media devices.
484 
485 config X86_INTEL_MID
486         bool "Intel MID platform support"
487         depends on X86_32
488         depends on X86_EXTENDED_PLATFORM
489         depends on X86_PLATFORM_DEVICES
490         depends on PCI
491         depends on PCI_GOANY
492         depends on X86_IO_APIC
493         select SFI
494         select I2C
495         select DW_APB_TIMER
496         select APB_TIMER
497         select INTEL_SCU_IPC
498         select MFD_INTEL_MSIC
499         ---help---
500           Select to build a kernel capable of supporting Intel MID (Mobile
501           Internet Device) platform systems which do not have the PCI legacy
502           interfaces. If you are building for a PC class system say N here.
503 
504           Intel MID platforms are based on an Intel processor and chipset which
505           consume less power than most of the x86 derivatives.
506 
507 config X86_INTEL_QUARK
508         bool "Intel Quark platform support"
509         depends on X86_32
510         depends on X86_EXTENDED_PLATFORM
511         depends on X86_PLATFORM_DEVICES
512         depends on X86_TSC
513         depends on PCI
514         depends on PCI_GOANY
515         depends on X86_IO_APIC
516         select IOSF_MBI
517         select INTEL_IMR
518         select COMMON_CLK
519         ---help---
520           Select to include support for Quark X1000 SoC.
521           Say Y here if you have a Quark based system such as the Arduino
522           compatible Intel Galileo.
523 
524 config X86_INTEL_LPSS
525         bool "Intel Low Power Subsystem Support"
526         depends on ACPI
527         select COMMON_CLK
528         select PINCTRL
529         ---help---
530           Select to build support for Intel Low Power Subsystem such as
531           found on Intel Lynxpoint PCH. Selecting this option enables
532           things like clock tree (common clock framework) and pincontrol
533           which are needed by the LPSS peripheral drivers.
534 
535 config X86_AMD_PLATFORM_DEVICE
536         bool "AMD ACPI2Platform devices support"
537         depends on ACPI
538         select COMMON_CLK
539         select PINCTRL
540         ---help---
541           Select to interpret AMD specific ACPI device to platform device
542           such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
543           I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
544           implemented under PINCTRL subsystem.
545 
546 config IOSF_MBI
547         tristate "Intel SoC IOSF Sideband support for SoC platforms"
548         depends on PCI
549         ---help---
550           This option enables sideband register access support for Intel SoC
551           platforms. On these platforms the IOSF sideband is used in lieu of
552           MSR's for some register accesses, mostly but not limited to thermal
553           and power. Drivers may query the availability of this device to
554           determine if they need the sideband in order to work on these
555           platforms. The sideband is available on the following SoC products.
556           This list is not meant to be exclusive.
557            - BayTrail
558            - Braswell
559            - Quark
560 
561           You should say Y if you are running a kernel on one of these SoC's.
562 
563 config IOSF_MBI_DEBUG
564         bool "Enable IOSF sideband access through debugfs"
565         depends on IOSF_MBI && DEBUG_FS
566         ---help---
567           Select this option to expose the IOSF sideband access registers (MCR,
568           MDR, MCRX) through debugfs to write and read register information from
569           different units on the SoC. This is most useful for obtaining device
570           state information for debug and analysis. As this is a general access
571           mechanism, users of this option would have specific knowledge of the
572           device they want to access.
573 
574           If you don't require the option or are in doubt, say N.
575 
576 config X86_RDC321X
577         bool "RDC R-321x SoC"
578         depends on X86_32
579         depends on X86_EXTENDED_PLATFORM
580         select M486
581         select X86_REBOOTFIXUPS
582         ---help---
583           This option is needed for RDC R-321x system-on-chip, also known
584           as R-8610-(G).
585           If you don't have one of these chips, you should say N here.
586 
587 config X86_32_NON_STANDARD
588         bool "Support non-standard 32-bit SMP architectures"
589         depends on X86_32 && SMP
590         depends on X86_EXTENDED_PLATFORM
591         ---help---
592           This option compiles in the bigsmp and STA2X11 default
593           subarchitectures.  It is intended for a generic binary
594           kernel. If you select them all, kernel will probe it one by
595           one and will fallback to default.
596 
597 # Alphabetically sorted list of Non standard 32 bit platforms
598 
599 config X86_SUPPORTS_MEMORY_FAILURE
600         def_bool y
601         # MCE code calls memory_failure():
602         depends on X86_MCE
603         # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
604         # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
605         depends on X86_64 || !SPARSEMEM
606         select ARCH_SUPPORTS_MEMORY_FAILURE
607 
608 config STA2X11
609         bool "STA2X11 Companion Chip Support"
610         depends on X86_32_NON_STANDARD && PCI
611         select X86_DEV_DMA_OPS
612         select X86_DMA_REMAP
613         select SWIOTLB
614         select MFD_STA2X11
615         select ARCH_REQUIRE_GPIOLIB
616         default n
617         ---help---
618           This adds support for boards based on the STA2X11 IO-Hub,
619           a.k.a. "ConneXt". The chip is used in place of the standard
620           PC chipset, so all "standard" peripherals are missing. If this
621           option is selected the kernel will still be able to boot on
622           standard PC machines.
623 
624 config X86_32_IRIS
625         tristate "Eurobraille/Iris poweroff module"
626         depends on X86_32
627         ---help---
628           The Iris machines from EuroBraille do not have APM or ACPI support
629           to shut themselves down properly.  A special I/O sequence is
630           needed to do so, which is what this module does at
631           kernel shutdown.
632 
633           This is only for Iris machines from EuroBraille.
634 
635           If unused, say N.
636 
637 config SCHED_OMIT_FRAME_POINTER
638         def_bool y
639         prompt "Single-depth WCHAN output"
640         depends on X86
641         ---help---
642           Calculate simpler /proc/<PID>/wchan values. If this option
643           is disabled then wchan values will recurse back to the
644           caller function. This provides more accurate wchan values,
645           at the expense of slightly more scheduling overhead.
646 
647           If in doubt, say "Y".
648 
649 menuconfig HYPERVISOR_GUEST
650         bool "Linux guest support"
651         ---help---
652           Say Y here to enable options for running Linux under various hyper-
653           visors. This option enables basic hypervisor detection and platform
654           setup.
655 
656           If you say N, all options in this submenu will be skipped and
657           disabled, and Linux guest support won't be built in.
658 
659 if HYPERVISOR_GUEST
660 
661 config PARAVIRT
662         bool "Enable paravirtualization code"
663         ---help---
664           This changes the kernel so it can modify itself when it is run
665           under a hypervisor, potentially improving performance significantly
666           over full virtualization.  However, when run without a hypervisor
667           the kernel is theoretically slower and slightly larger.
668 
669 config PARAVIRT_DEBUG
670         bool "paravirt-ops debugging"
671         depends on PARAVIRT && DEBUG_KERNEL
672         ---help---
673           Enable to debug paravirt_ops internals.  Specifically, BUG if
674           a paravirt_op is missing when it is called.
675 
676 config PARAVIRT_SPINLOCKS
677         bool "Paravirtualization layer for spinlocks"
678         depends on PARAVIRT && SMP
679         select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
680         ---help---
681           Paravirtualized spinlocks allow a pvops backend to replace the
682           spinlock implementation with something virtualization-friendly
683           (for example, block the virtual CPU rather than spinning).
684 
685           It has a minimal impact on native kernels and gives a nice performance
686           benefit on paravirtualized KVM / Xen kernels.
687 
688           If you are unsure how to answer this question, answer Y.
689 
690 source "arch/x86/xen/Kconfig"
691 
692 config KVM_GUEST
693         bool "KVM Guest support (including kvmclock)"
694         depends on PARAVIRT
695         select PARAVIRT_CLOCK
696         default y
697         ---help---
698           This option enables various optimizations for running under the KVM
699           hypervisor. It includes a paravirtualized clock, so that instead
700           of relying on a PIT (or probably other) emulation by the
701           underlying device model, the host provides the guest with
702           timing infrastructure such as time of day, and system time
703 
704 config KVM_DEBUG_FS
705         bool "Enable debug information for KVM Guests in debugfs"
706         depends on KVM_GUEST && DEBUG_FS
707         default n
708         ---help---
709           This option enables collection of various statistics for KVM guest.
710           Statistics are displayed in debugfs filesystem. Enabling this option
711           may incur significant overhead.
712 
713 source "arch/x86/lguest/Kconfig"
714 
715 config PARAVIRT_TIME_ACCOUNTING
716         bool "Paravirtual steal time accounting"
717         depends on PARAVIRT
718         default n
719         ---help---
720           Select this option to enable fine granularity task steal time
721           accounting. Time spent executing other tasks in parallel with
722           the current vCPU is discounted from the vCPU power. To account for
723           that, there can be a small performance impact.
724 
725           If in doubt, say N here.
726 
727 config PARAVIRT_CLOCK
728         bool
729 
730 endif #HYPERVISOR_GUEST
731 
732 config NO_BOOTMEM
733         def_bool y
734 
735 source "arch/x86/Kconfig.cpu"
736 
737 config HPET_TIMER
738         def_bool X86_64
739         prompt "HPET Timer Support" if X86_32
740         ---help---
741           Use the IA-PC HPET (High Precision Event Timer) to manage
742           time in preference to the PIT and RTC, if a HPET is
743           present.
744           HPET is the next generation timer replacing legacy 8254s.
745           The HPET provides a stable time base on SMP
746           systems, unlike the TSC, but it is more expensive to access,
747           as it is off-chip.  You can find the HPET spec at
748           <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
749 
750           You can safely choose Y here.  However, HPET will only be
751           activated if the platform and the BIOS support this feature.
752           Otherwise the 8254 will be used for timing services.
753 
754           Choose N to continue using the legacy 8254 timer.
755 
756 config HPET_EMULATE_RTC
757         def_bool y
758         depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
759 
760 config APB_TIMER
761        def_bool y if X86_INTEL_MID
762        prompt "Intel MID APB Timer Support" if X86_INTEL_MID
763        select DW_APB_TIMER
764        depends on X86_INTEL_MID && SFI
765        help
766          APB timer is the replacement for 8254, HPET on X86 MID platforms.
767          The APBT provides a stable time base on SMP
768          systems, unlike the TSC, but it is more expensive to access,
769          as it is off-chip. APB timers are always running regardless of CPU
770          C states, they are used as per CPU clockevent device when possible.
771 
772 # Mark as expert because too many people got it wrong.
773 # The code disables itself when not needed.
774 config DMI
775         default y
776         select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
777         bool "Enable DMI scanning" if EXPERT
778         ---help---
779           Enabled scanning of DMI to identify machine quirks. Say Y
780           here unless you have verified that your setup is not
781           affected by entries in the DMI blacklist. Required by PNP
782           BIOS code.
783 
784 config GART_IOMMU
785         bool "Old AMD GART IOMMU support"
786         select SWIOTLB
787         depends on X86_64 && PCI && AMD_NB
788         ---help---
789           Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
790           GART based hardware IOMMUs.
791 
792           The GART supports full DMA access for devices with 32-bit access
793           limitations, on systems with more than 3 GB. This is usually needed
794           for USB, sound, many IDE/SATA chipsets and some other devices.
795 
796           Newer systems typically have a modern AMD IOMMU, supported via
797           the CONFIG_AMD_IOMMU=y config option.
798 
799           In normal configurations this driver is only active when needed:
800           there's more than 3 GB of memory and the system contains a
801           32-bit limited device.
802 
803           If unsure, say Y.
804 
805 config CALGARY_IOMMU
806         bool "IBM Calgary IOMMU support"
807         select SWIOTLB
808         depends on X86_64 && PCI
809         ---help---
810           Support for hardware IOMMUs in IBM's xSeries x366 and x460
811           systems. Needed to run systems with more than 3GB of memory
812           properly with 32-bit PCI devices that do not support DAC
813           (Double Address Cycle). Calgary also supports bus level
814           isolation, where all DMAs pass through the IOMMU.  This
815           prevents them from going anywhere except their intended
816           destination. This catches hard-to-find kernel bugs and
817           mis-behaving drivers and devices that do not use the DMA-API
818           properly to set up their DMA buffers.  The IOMMU can be
819           turned off at boot time with the iommu=off parameter.
820           Normally the kernel will make the right choice by itself.
821           If unsure, say Y.
822 
823 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
824         def_bool y
825         prompt "Should Calgary be enabled by default?"
826         depends on CALGARY_IOMMU
827         ---help---
828           Should Calgary be enabled by default? if you choose 'y', Calgary
829           will be used (if it exists). If you choose 'n', Calgary will not be
830           used even if it exists. If you choose 'n' and would like to use
831           Calgary anyway, pass 'iommu=calgary' on the kernel command line.
832           If unsure, say Y.
833 
834 # need this always selected by IOMMU for the VIA workaround
835 config SWIOTLB
836         def_bool y if X86_64
837         ---help---
838           Support for software bounce buffers used on x86-64 systems
839           which don't have a hardware IOMMU. Using this PCI devices
840           which can only access 32-bits of memory can be used on systems
841           with more than 3 GB of memory.
842           If unsure, say Y.
843 
844 config IOMMU_HELPER
845         def_bool y
846         depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
847 
848 config MAXSMP
849         bool "Enable Maximum number of SMP Processors and NUMA Nodes"
850         depends on X86_64 && SMP && DEBUG_KERNEL
851         select CPUMASK_OFFSTACK
852         ---help---
853           Enable maximum number of CPUS and NUMA Nodes for this architecture.
854           If unsure, say N.
855 
856 config NR_CPUS
857         int "Maximum number of CPUs" if SMP && !MAXSMP
858         range 2 8 if SMP && X86_32 && !X86_BIGSMP
859         range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
860         range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
861         default "1" if !SMP
862         default "8192" if MAXSMP
863         default "32" if SMP && X86_BIGSMP
864         default "8" if SMP && X86_32
865         default "64" if SMP
866         ---help---
867           This allows you to specify the maximum number of CPUs which this
868           kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
869           supported value is 8192, otherwise the maximum value is 512.  The
870           minimum value which makes sense is 2.
871 
872           This is purely to save memory - each supported CPU adds
873           approximately eight kilobytes to the kernel image.
874 
875 config SCHED_SMT
876         bool "SMT (Hyperthreading) scheduler support"
877         depends on SMP
878         ---help---
879           SMT scheduler support improves the CPU scheduler's decision making
880           when dealing with Intel Pentium 4 chips with HyperThreading at a
881           cost of slightly increased overhead in some places. If unsure say
882           N here.
883 
884 config SCHED_MC
885         def_bool y
886         prompt "Multi-core scheduler support"
887         depends on SMP
888         ---help---
889           Multi-core scheduler support improves the CPU scheduler's decision
890           making when dealing with multi-core CPU chips at a cost of slightly
891           increased overhead in some places. If unsure say N here.
892 
893 source "kernel/Kconfig.preempt"
894 
895 config UP_LATE_INIT
896        def_bool y
897        depends on !SMP && X86_LOCAL_APIC
898 
899 config X86_UP_APIC
900         bool "Local APIC support on uniprocessors" if !PCI_MSI
901         default PCI_MSI
902         depends on X86_32 && !SMP && !X86_32_NON_STANDARD
903         ---help---
904           A local APIC (Advanced Programmable Interrupt Controller) is an
905           integrated interrupt controller in the CPU. If you have a single-CPU
906           system which has a processor with a local APIC, you can say Y here to
907           enable and use it. If you say Y here even though your machine doesn't
908           have a local APIC, then the kernel will still run with no slowdown at
909           all. The local APIC supports CPU-generated self-interrupts (timer,
910           performance counters), and the NMI watchdog which detects hard
911           lockups.
912 
913 config X86_UP_IOAPIC
914         bool "IO-APIC support on uniprocessors"
915         depends on X86_UP_APIC
916         ---help---
917           An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
918           SMP-capable replacement for PC-style interrupt controllers. Most
919           SMP systems and many recent uniprocessor systems have one.
920 
921           If you have a single-CPU system with an IO-APIC, you can say Y here
922           to use it. If you say Y here even though your machine doesn't have
923           an IO-APIC, then the kernel will still run with no slowdown at all.
924 
925 config X86_LOCAL_APIC
926         def_bool y
927         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
928         select IRQ_DOMAIN_HIERARCHY
929         select PCI_MSI_IRQ_DOMAIN if PCI_MSI
930 
931 config X86_IO_APIC
932         def_bool y
933         depends on X86_LOCAL_APIC || X86_UP_IOAPIC
934 
935 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
936         bool "Reroute for broken boot IRQs"
937         depends on X86_IO_APIC
938         ---help---
939           This option enables a workaround that fixes a source of
940           spurious interrupts. This is recommended when threaded
941           interrupt handling is used on systems where the generation of
942           superfluous "boot interrupts" cannot be disabled.
943 
944           Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
945           entry in the chipset's IO-APIC is masked (as, e.g. the RT
946           kernel does during interrupt handling). On chipsets where this
947           boot IRQ generation cannot be disabled, this workaround keeps
948           the original IRQ line masked so that only the equivalent "boot
949           IRQ" is delivered to the CPUs. The workaround also tells the
950           kernel to set up the IRQ handler on the boot IRQ line. In this
951           way only one interrupt is delivered to the kernel. Otherwise
952           the spurious second interrupt may cause the kernel to bring
953           down (vital) interrupt lines.
954 
955           Only affects "broken" chipsets. Interrupt sharing may be
956           increased on these systems.
957 
958 config X86_MCE
959         bool "Machine Check / overheating reporting"
960         select GENERIC_ALLOCATOR
961         default y
962         ---help---
963           Machine Check support allows the processor to notify the
964           kernel if it detects a problem (e.g. overheating, data corruption).
965           The action the kernel takes depends on the severity of the problem,
966           ranging from warning messages to halting the machine.
967 
968 config X86_MCE_INTEL
969         def_bool y
970         prompt "Intel MCE features"
971         depends on X86_MCE && X86_LOCAL_APIC
972         ---help---
973            Additional support for intel specific MCE features such as
974            the thermal monitor.
975 
976 config X86_MCE_AMD
977         def_bool y
978         prompt "AMD MCE features"
979         depends on X86_MCE && X86_LOCAL_APIC
980         ---help---
981            Additional support for AMD specific MCE features such as
982            the DRAM Error Threshold.
983 
984 config X86_ANCIENT_MCE
985         bool "Support for old Pentium 5 / WinChip machine checks"
986         depends on X86_32 && X86_MCE
987         ---help---
988           Include support for machine check handling on old Pentium 5 or WinChip
989           systems. These typically need to be enabled explicitly on the command
990           line.
991 
992 config X86_MCE_THRESHOLD
993         depends on X86_MCE_AMD || X86_MCE_INTEL
994         def_bool y
995 
996 config X86_MCE_INJECT
997         depends on X86_MCE
998         tristate "Machine check injector support"
999         ---help---
1000           Provide support for injecting machine checks for testing purposes.
1001           If you don't know what a machine check is and you don't do kernel
1002           QA it is safe to say n.
1003 
1004 config X86_THERMAL_VECTOR
1005         def_bool y
1006         depends on X86_MCE_INTEL
1007 
1008 config X86_LEGACY_VM86
1009         bool "Legacy VM86 support"
1010         default n
1011         depends on X86_32
1012         ---help---
1013           This option allows user programs to put the CPU into V8086
1014           mode, which is an 80286-era approximation of 16-bit real mode.
1015 
1016           Some very old versions of X and/or vbetool require this option
1017           for user mode setting.  Similarly, DOSEMU will use it if
1018           available to accelerate real mode DOS programs.  However, any
1019           recent version of DOSEMU, X, or vbetool should be fully
1020           functional even without kernel VM86 support, as they will all
1021           fall back to software emulation. Nevertheless, if you are using
1022           a 16-bit DOS program where 16-bit performance matters, vm86
1023           mode might be faster than emulation and you might want to
1024           enable this option.
1025 
1026           Note that any app that works on a 64-bit kernel is unlikely to
1027           need this option, as 64-bit kernels don't, and can't, support
1028           V8086 mode. This option is also unrelated to 16-bit protected
1029           mode and is not needed to run most 16-bit programs under Wine.
1030 
1031           Enabling this option increases the complexity of the kernel
1032           and slows down exception handling a tiny bit.
1033 
1034           If unsure, say N here.
1035 
1036 config VM86
1037        bool
1038        default X86_LEGACY_VM86
1039 
1040 config X86_16BIT
1041         bool "Enable support for 16-bit segments" if EXPERT
1042         default y
1043         depends on MODIFY_LDT_SYSCALL
1044         ---help---
1045           This option is required by programs like Wine to run 16-bit
1046           protected mode legacy code on x86 processors.  Disabling
1047           this option saves about 300 bytes on i386, or around 6K text
1048           plus 16K runtime memory on x86-64,
1049 
1050 config X86_ESPFIX32
1051         def_bool y
1052         depends on X86_16BIT && X86_32
1053 
1054 config X86_ESPFIX64
1055         def_bool y
1056         depends on X86_16BIT && X86_64
1057 
1058 config X86_VSYSCALL_EMULATION
1059        bool "Enable vsyscall emulation" if EXPERT
1060        default y
1061        depends on X86_64
1062        ---help---
1063          This enables emulation of the legacy vsyscall page.  Disabling
1064          it is roughly equivalent to booting with vsyscall=none, except
1065          that it will also disable the helpful warning if a program
1066          tries to use a vsyscall.  With this option set to N, offending
1067          programs will just segfault, citing addresses of the form
1068          0xffffffffff600?00.
1069 
1070          This option is required by many programs built before 2013, and
1071          care should be used even with newer programs if set to N.
1072 
1073          Disabling this option saves about 7K of kernel size and
1074          possibly 4K of additional runtime pagetable memory.
1075 
1076 config TOSHIBA
1077         tristate "Toshiba Laptop support"
1078         depends on X86_32
1079         ---help---
1080           This adds a driver to safely access the System Management Mode of
1081           the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1082           not work on models with a Phoenix BIOS. The System Management Mode
1083           is used to set the BIOS and power saving options on Toshiba portables.
1084 
1085           For information on utilities to make use of this driver see the
1086           Toshiba Linux utilities web site at:
1087           <http://www.buzzard.org.uk/toshiba/>.
1088 
1089           Say Y if you intend to run this kernel on a Toshiba portable.
1090           Say N otherwise.
1091 
1092 config I8K
1093         tristate "Dell i8k legacy laptop support"
1094         select HWMON
1095         select SENSORS_DELL_SMM
1096         ---help---
1097           This option enables legacy /proc/i8k userspace interface in hwmon
1098           dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1099           temperature and allows controlling fan speeds of Dell laptops via
1100           System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1101           it reports also power and hotkey status. For fan speed control is
1102           needed userspace package i8kutils.
1103 
1104           Say Y if you intend to run this kernel on old Dell laptops or want to
1105           use userspace package i8kutils.
1106           Say N otherwise.
1107 
1108 config X86_REBOOTFIXUPS
1109         bool "Enable X86 board specific fixups for reboot"
1110         depends on X86_32
1111         ---help---
1112           This enables chipset and/or board specific fixups to be done
1113           in order to get reboot to work correctly. This is only needed on
1114           some combinations of hardware and BIOS. The symptom, for which
1115           this config is intended, is when reboot ends with a stalled/hung
1116           system.
1117 
1118           Currently, the only fixup is for the Geode machines using
1119           CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1120 
1121           Say Y if you want to enable the fixup. Currently, it's safe to
1122           enable this option even if you don't need it.
1123           Say N otherwise.
1124 
1125 config MICROCODE
1126         bool "CPU microcode loading support"
1127         default y
1128         depends on CPU_SUP_AMD || CPU_SUP_INTEL
1129         depends on BLK_DEV_INITRD
1130         select FW_LOADER
1131         ---help---
1132 
1133           If you say Y here, you will be able to update the microcode on
1134           certain Intel and AMD processors. The Intel support is for the
1135           IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1136           Xeon etc. The AMD support is for families 0x10 and later. You will
1137           obviously need the actual microcode binary data itself which is not
1138           shipped with the Linux kernel.
1139 
1140           This option selects the general module only, you need to select
1141           at least one vendor specific module as well.
1142 
1143           To compile this driver as a module, choose M here: the module
1144           will be called microcode.
1145 
1146 config MICROCODE_INTEL
1147         bool "Intel microcode loading support"
1148         depends on MICROCODE
1149         default MICROCODE
1150         select FW_LOADER
1151         ---help---
1152           This options enables microcode patch loading support for Intel
1153           processors.
1154 
1155           For the current Intel microcode data package go to
1156           <https://downloadcenter.intel.com> and search for
1157           'Linux Processor Microcode Data File'.
1158 
1159 config MICROCODE_AMD
1160         bool "AMD microcode loading support"
1161         depends on MICROCODE
1162         select FW_LOADER
1163         ---help---
1164           If you select this option, microcode patch loading support for AMD
1165           processors will be enabled.
1166 
1167 config MICROCODE_OLD_INTERFACE
1168         def_bool y
1169         depends on MICROCODE
1170 
1171 config X86_MSR
1172         tristate "/dev/cpu/*/msr - Model-specific register support"
1173         ---help---
1174           This device gives privileged processes access to the x86
1175           Model-Specific Registers (MSRs).  It is a character device with
1176           major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1177           MSR accesses are directed to a specific CPU on multi-processor
1178           systems.
1179 
1180 config X86_CPUID
1181         tristate "/dev/cpu/*/cpuid - CPU information support"
1182         ---help---
1183           This device gives processes access to the x86 CPUID instruction to
1184           be executed on a specific processor.  It is a character device
1185           with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1186           /dev/cpu/31/cpuid.
1187 
1188 choice
1189         prompt "High Memory Support"
1190         default HIGHMEM4G
1191         depends on X86_32
1192 
1193 config NOHIGHMEM
1194         bool "off"
1195         ---help---
1196           Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1197           However, the address space of 32-bit x86 processors is only 4
1198           Gigabytes large. That means that, if you have a large amount of
1199           physical memory, not all of it can be "permanently mapped" by the
1200           kernel. The physical memory that's not permanently mapped is called
1201           "high memory".
1202 
1203           If you are compiling a kernel which will never run on a machine with
1204           more than 1 Gigabyte total physical RAM, answer "off" here (default
1205           choice and suitable for most users). This will result in a "3GB/1GB"
1206           split: 3GB are mapped so that each process sees a 3GB virtual memory
1207           space and the remaining part of the 4GB virtual memory space is used
1208           by the kernel to permanently map as much physical memory as
1209           possible.
1210 
1211           If the machine has between 1 and 4 Gigabytes physical RAM, then
1212           answer "4GB" here.
1213 
1214           If more than 4 Gigabytes is used then answer "64GB" here. This
1215           selection turns Intel PAE (Physical Address Extension) mode on.
1216           PAE implements 3-level paging on IA32 processors. PAE is fully
1217           supported by Linux, PAE mode is implemented on all recent Intel
1218           processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1219           then the kernel will not boot on CPUs that don't support PAE!
1220 
1221           The actual amount of total physical memory will either be
1222           auto detected or can be forced by using a kernel command line option
1223           such as "mem=256M". (Try "man bootparam" or see the documentation of
1224           your boot loader (lilo or loadlin) about how to pass options to the
1225           kernel at boot time.)
1226 
1227           If unsure, say "off".
1228 
1229 config HIGHMEM4G
1230         bool "4GB"
1231         ---help---
1232           Select this if you have a 32-bit processor and between 1 and 4
1233           gigabytes of physical RAM.
1234 
1235 config HIGHMEM64G
1236         bool "64GB"
1237         depends on !M486
1238         select X86_PAE
1239         ---help---
1240           Select this if you have a 32-bit processor and more than 4
1241           gigabytes of physical RAM.
1242 
1243 endchoice
1244 
1245 choice
1246         prompt "Memory split" if EXPERT
1247         default VMSPLIT_3G
1248         depends on X86_32
1249         ---help---
1250           Select the desired split between kernel and user memory.
1251 
1252           If the address range available to the kernel is less than the
1253           physical memory installed, the remaining memory will be available
1254           as "high memory". Accessing high memory is a little more costly
1255           than low memory, as it needs to be mapped into the kernel first.
1256           Note that increasing the kernel address space limits the range
1257           available to user programs, making the address space there
1258           tighter.  Selecting anything other than the default 3G/1G split
1259           will also likely make your kernel incompatible with binary-only
1260           kernel modules.
1261 
1262           If you are not absolutely sure what you are doing, leave this
1263           option alone!
1264 
1265         config VMSPLIT_3G
1266                 bool "3G/1G user/kernel split"
1267         config VMSPLIT_3G_OPT
1268                 depends on !X86_PAE
1269                 bool "3G/1G user/kernel split (for full 1G low memory)"
1270         config VMSPLIT_2G
1271                 bool "2G/2G user/kernel split"
1272         config VMSPLIT_2G_OPT
1273                 depends on !X86_PAE
1274                 bool "2G/2G user/kernel split (for full 2G low memory)"
1275         config VMSPLIT_1G
1276                 bool "1G/3G user/kernel split"
1277 endchoice
1278 
1279 config PAGE_OFFSET
1280         hex
1281         default 0xB0000000 if VMSPLIT_3G_OPT
1282         default 0x80000000 if VMSPLIT_2G
1283         default 0x78000000 if VMSPLIT_2G_OPT
1284         default 0x40000000 if VMSPLIT_1G
1285         default 0xC0000000
1286         depends on X86_32
1287 
1288 config HIGHMEM
1289         def_bool y
1290         depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1291 
1292 config X86_PAE
1293         bool "PAE (Physical Address Extension) Support"
1294         depends on X86_32 && !HIGHMEM4G
1295         select SWIOTLB
1296         ---help---
1297           PAE is required for NX support, and furthermore enables
1298           larger swapspace support for non-overcommit purposes. It
1299           has the cost of more pagetable lookup overhead, and also
1300           consumes more pagetable space per process.
1301 
1302 config ARCH_PHYS_ADDR_T_64BIT
1303         def_bool y
1304         depends on X86_64 || X86_PAE
1305 
1306 config ARCH_DMA_ADDR_T_64BIT
1307         def_bool y
1308         depends on X86_64 || HIGHMEM64G
1309 
1310 config X86_DIRECT_GBPAGES
1311         def_bool y
1312         depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1313         ---help---
1314           Certain kernel features effectively disable kernel
1315           linear 1 GB mappings (even if the CPU otherwise
1316           supports them), so don't confuse the user by printing
1317           that we have them enabled.
1318 
1319 # Common NUMA Features
1320 config NUMA
1321         bool "Numa Memory Allocation and Scheduler Support"
1322         depends on SMP
1323         depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1324         default y if X86_BIGSMP
1325         ---help---
1326           Enable NUMA (Non Uniform Memory Access) support.
1327 
1328           The kernel will try to allocate memory used by a CPU on the
1329           local memory controller of the CPU and add some more
1330           NUMA awareness to the kernel.
1331 
1332           For 64-bit this is recommended if the system is Intel Core i7
1333           (or later), AMD Opteron, or EM64T NUMA.
1334 
1335           For 32-bit this is only needed if you boot a 32-bit
1336           kernel on a 64-bit NUMA platform.
1337 
1338           Otherwise, you should say N.
1339 
1340 config AMD_NUMA
1341         def_bool y
1342         prompt "Old style AMD Opteron NUMA detection"
1343         depends on X86_64 && NUMA && PCI
1344         ---help---
1345           Enable AMD NUMA node topology detection.  You should say Y here if
1346           you have a multi processor AMD system. This uses an old method to
1347           read the NUMA configuration directly from the builtin Northbridge
1348           of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1349           which also takes priority if both are compiled in.
1350 
1351 config X86_64_ACPI_NUMA
1352         def_bool y
1353         prompt "ACPI NUMA detection"
1354         depends on X86_64 && NUMA && ACPI && PCI
1355         select ACPI_NUMA
1356         ---help---
1357           Enable ACPI SRAT based node topology detection.
1358 
1359 # Some NUMA nodes have memory ranges that span
1360 # other nodes.  Even though a pfn is valid and
1361 # between a node's start and end pfns, it may not
1362 # reside on that node.  See memmap_init_zone()
1363 # for details.
1364 config NODES_SPAN_OTHER_NODES
1365         def_bool y
1366         depends on X86_64_ACPI_NUMA
1367 
1368 config NUMA_EMU
1369         bool "NUMA emulation"
1370         depends on NUMA
1371         ---help---
1372           Enable NUMA emulation. A flat machine will be split
1373           into virtual nodes when booted with "numa=fake=N", where N is the
1374           number of nodes. This is only useful for debugging.
1375 
1376 config NODES_SHIFT
1377         int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1378         range 1 10
1379         default "10" if MAXSMP
1380         default "6" if X86_64
1381         default "3"
1382         depends on NEED_MULTIPLE_NODES
1383         ---help---
1384           Specify the maximum number of NUMA Nodes available on the target
1385           system.  Increases memory reserved to accommodate various tables.
1386 
1387 config ARCH_HAVE_MEMORY_PRESENT
1388         def_bool y
1389         depends on X86_32 && DISCONTIGMEM
1390 
1391 config NEED_NODE_MEMMAP_SIZE
1392         def_bool y
1393         depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1394 
1395 config ARCH_FLATMEM_ENABLE
1396         def_bool y
1397         depends on X86_32 && !NUMA
1398 
1399 config ARCH_DISCONTIGMEM_ENABLE
1400         def_bool y
1401         depends on NUMA && X86_32
1402 
1403 config ARCH_DISCONTIGMEM_DEFAULT
1404         def_bool y
1405         depends on NUMA && X86_32
1406 
1407 config ARCH_SPARSEMEM_ENABLE
1408         def_bool y
1409         depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1410         select SPARSEMEM_STATIC if X86_32
1411         select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1412 
1413 config ARCH_SPARSEMEM_DEFAULT
1414         def_bool y
1415         depends on X86_64
1416 
1417 config ARCH_SELECT_MEMORY_MODEL
1418         def_bool y
1419         depends on ARCH_SPARSEMEM_ENABLE
1420 
1421 config ARCH_MEMORY_PROBE
1422         bool "Enable sysfs memory/probe interface"
1423         depends on X86_64 && MEMORY_HOTPLUG
1424         help
1425           This option enables a sysfs memory/probe interface for testing.
1426           See Documentation/memory-hotplug.txt for more information.
1427           If you are unsure how to answer this question, answer N.
1428 
1429 config ARCH_PROC_KCORE_TEXT
1430         def_bool y
1431         depends on X86_64 && PROC_KCORE
1432 
1433 config ILLEGAL_POINTER_VALUE
1434        hex
1435        default 0 if X86_32
1436        default 0xdead000000000000 if X86_64
1437 
1438 source "mm/Kconfig"
1439 
1440 config X86_PMEM_LEGACY_DEVICE
1441         bool
1442 
1443 config X86_PMEM_LEGACY
1444         tristate "Support non-standard NVDIMMs and ADR protected memory"
1445         depends on PHYS_ADDR_T_64BIT
1446         depends on BLK_DEV
1447         select X86_PMEM_LEGACY_DEVICE
1448         select LIBNVDIMM
1449         help
1450           Treat memory marked using the non-standard e820 type of 12 as used
1451           by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1452           The kernel will offer these regions to the 'pmem' driver so
1453           they can be used for persistent storage.
1454 
1455           Say Y if unsure.
1456 
1457 config HIGHPTE
1458         bool "Allocate 3rd-level pagetables from highmem"
1459         depends on HIGHMEM
1460         ---help---
1461           The VM uses one page table entry for each page of physical memory.
1462           For systems with a lot of RAM, this can be wasteful of precious
1463           low memory.  Setting this option will put user-space page table
1464           entries in high memory.
1465 
1466 config X86_CHECK_BIOS_CORRUPTION
1467         bool "Check for low memory corruption"
1468         ---help---
1469           Periodically check for memory corruption in low memory, which
1470           is suspected to be caused by BIOS.  Even when enabled in the
1471           configuration, it is disabled at runtime.  Enable it by
1472           setting "memory_corruption_check=1" on the kernel command
1473           line.  By default it scans the low 64k of memory every 60
1474           seconds; see the memory_corruption_check_size and
1475           memory_corruption_check_period parameters in
1476           Documentation/kernel-parameters.txt to adjust this.
1477 
1478           When enabled with the default parameters, this option has
1479           almost no overhead, as it reserves a relatively small amount
1480           of memory and scans it infrequently.  It both detects corruption
1481           and prevents it from affecting the running system.
1482 
1483           It is, however, intended as a diagnostic tool; if repeatable
1484           BIOS-originated corruption always affects the same memory,
1485           you can use memmap= to prevent the kernel from using that
1486           memory.
1487 
1488 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1489         bool "Set the default setting of memory_corruption_check"
1490         depends on X86_CHECK_BIOS_CORRUPTION
1491         default y
1492         ---help---
1493           Set whether the default state of memory_corruption_check is
1494           on or off.
1495 
1496 config X86_RESERVE_LOW
1497         int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1498         default 64
1499         range 4 640
1500         ---help---
1501           Specify the amount of low memory to reserve for the BIOS.
1502 
1503           The first page contains BIOS data structures that the kernel
1504           must not use, so that page must always be reserved.
1505 
1506           By default we reserve the first 64K of physical RAM, as a
1507           number of BIOSes are known to corrupt that memory range
1508           during events such as suspend/resume or monitor cable
1509           insertion, so it must not be used by the kernel.
1510 
1511           You can set this to 4 if you are absolutely sure that you
1512           trust the BIOS to get all its memory reservations and usages
1513           right.  If you know your BIOS have problems beyond the
1514           default 64K area, you can set this to 640 to avoid using the
1515           entire low memory range.
1516 
1517           If you have doubts about the BIOS (e.g. suspend/resume does
1518           not work or there's kernel crashes after certain hardware
1519           hotplug events) then you might want to enable
1520           X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1521           typical corruption patterns.
1522 
1523           Leave this to the default value of 64 if you are unsure.
1524 
1525 config MATH_EMULATION
1526         bool
1527         depends on MODIFY_LDT_SYSCALL
1528         prompt "Math emulation" if X86_32
1529         ---help---
1530           Linux can emulate a math coprocessor (used for floating point
1531           operations) if you don't have one. 486DX and Pentium processors have
1532           a math coprocessor built in, 486SX and 386 do not, unless you added
1533           a 487DX or 387, respectively. (The messages during boot time can
1534           give you some hints here ["man dmesg"].) Everyone needs either a
1535           coprocessor or this emulation.
1536 
1537           If you don't have a math coprocessor, you need to say Y here; if you
1538           say Y here even though you have a coprocessor, the coprocessor will
1539           be used nevertheless. (This behavior can be changed with the kernel
1540           command line option "no387", which comes handy if your coprocessor
1541           is broken. Try "man bootparam" or see the documentation of your boot
1542           loader (lilo or loadlin) about how to pass options to the kernel at
1543           boot time.) This means that it is a good idea to say Y here if you
1544           intend to use this kernel on different machines.
1545 
1546           More information about the internals of the Linux math coprocessor
1547           emulation can be found in <file:arch/x86/math-emu/README>.
1548 
1549           If you are not sure, say Y; apart from resulting in a 66 KB bigger
1550           kernel, it won't hurt.
1551 
1552 config MTRR
1553         def_bool y
1554         prompt "MTRR (Memory Type Range Register) support" if EXPERT
1555         ---help---
1556           On Intel P6 family processors (Pentium Pro, Pentium II and later)
1557           the Memory Type Range Registers (MTRRs) may be used to control
1558           processor access to memory ranges. This is most useful if you have
1559           a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1560           allows bus write transfers to be combined into a larger transfer
1561           before bursting over the PCI/AGP bus. This can increase performance
1562           of image write operations 2.5 times or more. Saying Y here creates a
1563           /proc/mtrr file which may be used to manipulate your processor's
1564           MTRRs. Typically the X server should use this.
1565 
1566           This code has a reasonably generic interface so that similar
1567           control registers on other processors can be easily supported
1568           as well:
1569 
1570           The Cyrix 6x86, 6x86MX and M II processors have Address Range
1571           Registers (ARRs) which provide a similar functionality to MTRRs. For
1572           these, the ARRs are used to emulate the MTRRs.
1573           The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1574           MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1575           write-combining. All of these processors are supported by this code
1576           and it makes sense to say Y here if you have one of them.
1577 
1578           Saying Y here also fixes a problem with buggy SMP BIOSes which only
1579           set the MTRRs for the boot CPU and not for the secondary CPUs. This
1580           can lead to all sorts of problems, so it's good to say Y here.
1581 
1582           You can safely say Y even if your machine doesn't have MTRRs, you'll
1583           just add about 9 KB to your kernel.
1584 
1585           See <file:Documentation/x86/mtrr.txt> for more information.
1586 
1587 config MTRR_SANITIZER
1588         def_bool y
1589         prompt "MTRR cleanup support"
1590         depends on MTRR
1591         ---help---
1592           Convert MTRR layout from continuous to discrete, so X drivers can
1593           add writeback entries.
1594 
1595           Can be disabled with disable_mtrr_cleanup on the kernel command line.
1596           The largest mtrr entry size for a continuous block can be set with
1597           mtrr_chunk_size.
1598 
1599           If unsure, say Y.
1600 
1601 config MTRR_SANITIZER_ENABLE_DEFAULT
1602         int "MTRR cleanup enable value (0-1)"
1603         range 0 1
1604         default "0"
1605         depends on MTRR_SANITIZER
1606         ---help---
1607           Enable mtrr cleanup default value
1608 
1609 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1610         int "MTRR cleanup spare reg num (0-7)"
1611         range 0 7
1612         default "1"
1613         depends on MTRR_SANITIZER
1614         ---help---
1615           mtrr cleanup spare entries default, it can be changed via
1616           mtrr_spare_reg_nr=N on the kernel command line.
1617 
1618 config X86_PAT
1619         def_bool y
1620         prompt "x86 PAT support" if EXPERT
1621         depends on MTRR
1622         ---help---
1623           Use PAT attributes to setup page level cache control.
1624 
1625           PATs are the modern equivalents of MTRRs and are much more
1626           flexible than MTRRs.
1627 
1628           Say N here if you see bootup problems (boot crash, boot hang,
1629           spontaneous reboots) or a non-working video driver.
1630 
1631           If unsure, say Y.
1632 
1633 config ARCH_USES_PG_UNCACHED
1634         def_bool y
1635         depends on X86_PAT
1636 
1637 config ARCH_RANDOM
1638         def_bool y
1639         prompt "x86 architectural random number generator" if EXPERT
1640         ---help---
1641           Enable the x86 architectural RDRAND instruction
1642           (Intel Bull Mountain technology) to generate random numbers.
1643           If supported, this is a high bandwidth, cryptographically
1644           secure hardware random number generator.
1645 
1646 config X86_SMAP
1647         def_bool y
1648         prompt "Supervisor Mode Access Prevention" if EXPERT
1649         ---help---
1650           Supervisor Mode Access Prevention (SMAP) is a security
1651           feature in newer Intel processors.  There is a small
1652           performance cost if this enabled and turned on; there is
1653           also a small increase in the kernel size if this is enabled.
1654 
1655           If unsure, say Y.
1656 
1657 config X86_INTEL_MPX
1658         prompt "Intel MPX (Memory Protection Extensions)"
1659         def_bool n
1660         depends on CPU_SUP_INTEL
1661         ---help---
1662           MPX provides hardware features that can be used in
1663           conjunction with compiler-instrumented code to check
1664           memory references.  It is designed to detect buffer
1665           overflow or underflow bugs.
1666 
1667           This option enables running applications which are
1668           instrumented or otherwise use MPX.  It does not use MPX
1669           itself inside the kernel or to protect the kernel
1670           against bad memory references.
1671 
1672           Enabling this option will make the kernel larger:
1673           ~8k of kernel text and 36 bytes of data on a 64-bit
1674           defconfig.  It adds a long to the 'mm_struct' which
1675           will increase the kernel memory overhead of each
1676           process and adds some branches to paths used during
1677           exec() and munmap().
1678 
1679           For details, see Documentation/x86/intel_mpx.txt
1680 
1681           If unsure, say N.
1682 
1683 config EFI
1684         bool "EFI runtime service support"
1685         depends on ACPI
1686         select UCS2_STRING
1687         select EFI_RUNTIME_WRAPPERS
1688         ---help---
1689           This enables the kernel to use EFI runtime services that are
1690           available (such as the EFI variable services).
1691 
1692           This option is only useful on systems that have EFI firmware.
1693           In addition, you should use the latest ELILO loader available
1694           at <http://elilo.sourceforge.net> in order to take advantage
1695           of EFI runtime services. However, even with this option, the
1696           resultant kernel should continue to boot on existing non-EFI
1697           platforms.
1698 
1699 config EFI_STUB
1700        bool "EFI stub support"
1701        depends on EFI && !X86_USE_3DNOW
1702        select RELOCATABLE
1703        ---help---
1704           This kernel feature allows a bzImage to be loaded directly
1705           by EFI firmware without the use of a bootloader.
1706 
1707           See Documentation/efi-stub.txt for more information.
1708 
1709 config EFI_MIXED
1710         bool "EFI mixed-mode support"
1711         depends on EFI_STUB && X86_64
1712         ---help---
1713            Enabling this feature allows a 64-bit kernel to be booted
1714            on a 32-bit firmware, provided that your CPU supports 64-bit
1715            mode.
1716 
1717            Note that it is not possible to boot a mixed-mode enabled
1718            kernel via the EFI boot stub - a bootloader that supports
1719            the EFI handover protocol must be used.
1720 
1721            If unsure, say N.
1722 
1723 config SECCOMP
1724         def_bool y
1725         prompt "Enable seccomp to safely compute untrusted bytecode"
1726         ---help---
1727           This kernel feature is useful for number crunching applications
1728           that may need to compute untrusted bytecode during their
1729           execution. By using pipes or other transports made available to
1730           the process as file descriptors supporting the read/write
1731           syscalls, it's possible to isolate those applications in
1732           their own address space using seccomp. Once seccomp is
1733           enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1734           and the task is only allowed to execute a few safe syscalls
1735           defined by each seccomp mode.
1736 
1737           If unsure, say Y. Only embedded should say N here.
1738 
1739 source kernel/Kconfig.hz
1740 
1741 config KEXEC
1742         bool "kexec system call"
1743         select KEXEC_CORE
1744         ---help---
1745           kexec is a system call that implements the ability to shutdown your
1746           current kernel, and to start another kernel.  It is like a reboot
1747           but it is independent of the system firmware.   And like a reboot
1748           you can start any kernel with it, not just Linux.
1749 
1750           The name comes from the similarity to the exec system call.
1751 
1752           It is an ongoing process to be certain the hardware in a machine
1753           is properly shutdown, so do not be surprised if this code does not
1754           initially work for you.  As of this writing the exact hardware
1755           interface is strongly in flux, so no good recommendation can be
1756           made.
1757 
1758 config KEXEC_FILE
1759         bool "kexec file based system call"
1760         select KEXEC_CORE
1761         select BUILD_BIN2C
1762         depends on X86_64
1763         depends on CRYPTO=y
1764         depends on CRYPTO_SHA256=y
1765         ---help---
1766           This is new version of kexec system call. This system call is
1767           file based and takes file descriptors as system call argument
1768           for kernel and initramfs as opposed to list of segments as
1769           accepted by previous system call.
1770 
1771 config KEXEC_VERIFY_SIG
1772         bool "Verify kernel signature during kexec_file_load() syscall"
1773         depends on KEXEC_FILE
1774         ---help---
1775           This option makes kernel signature verification mandatory for
1776           the kexec_file_load() syscall.
1777 
1778           In addition to that option, you need to enable signature
1779           verification for the corresponding kernel image type being
1780           loaded in order for this to work.
1781 
1782 config KEXEC_BZIMAGE_VERIFY_SIG
1783         bool "Enable bzImage signature verification support"
1784         depends on KEXEC_VERIFY_SIG
1785         depends on SIGNED_PE_FILE_VERIFICATION
1786         select SYSTEM_TRUSTED_KEYRING
1787         ---help---
1788           Enable bzImage signature verification support.
1789 
1790 config CRASH_DUMP
1791         bool "kernel crash dumps"
1792         depends on X86_64 || (X86_32 && HIGHMEM)
1793         ---help---
1794           Generate crash dump after being started by kexec.
1795           This should be normally only set in special crash dump kernels
1796           which are loaded in the main kernel with kexec-tools into
1797           a specially reserved region and then later executed after
1798           a crash by kdump/kexec. The crash dump kernel must be compiled
1799           to a memory address not used by the main kernel or BIOS using
1800           PHYSICAL_START, or it must be built as a relocatable image
1801           (CONFIG_RELOCATABLE=y).
1802           For more details see Documentation/kdump/kdump.txt
1803 
1804 config KEXEC_JUMP
1805         bool "kexec jump"
1806         depends on KEXEC && HIBERNATION
1807         ---help---
1808           Jump between original kernel and kexeced kernel and invoke
1809           code in physical address mode via KEXEC
1810 
1811 config PHYSICAL_START
1812         hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1813         default "0x1000000"
1814         ---help---
1815           This gives the physical address where the kernel is loaded.
1816 
1817           If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1818           bzImage will decompress itself to above physical address and
1819           run from there. Otherwise, bzImage will run from the address where
1820           it has been loaded by the boot loader and will ignore above physical
1821           address.
1822 
1823           In normal kdump cases one does not have to set/change this option
1824           as now bzImage can be compiled as a completely relocatable image
1825           (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1826           address. This option is mainly useful for the folks who don't want
1827           to use a bzImage for capturing the crash dump and want to use a
1828           vmlinux instead. vmlinux is not relocatable hence a kernel needs
1829           to be specifically compiled to run from a specific memory area
1830           (normally a reserved region) and this option comes handy.
1831 
1832           So if you are using bzImage for capturing the crash dump,
1833           leave the value here unchanged to 0x1000000 and set
1834           CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
1835           for capturing the crash dump change this value to start of
1836           the reserved region.  In other words, it can be set based on
1837           the "X" value as specified in the "crashkernel=YM@XM"
1838           command line boot parameter passed to the panic-ed
1839           kernel. Please take a look at Documentation/kdump/kdump.txt
1840           for more details about crash dumps.
1841 
1842           Usage of bzImage for capturing the crash dump is recommended as
1843           one does not have to build two kernels. Same kernel can be used
1844           as production kernel and capture kernel. Above option should have
1845           gone away after relocatable bzImage support is introduced. But it
1846           is present because there are users out there who continue to use
1847           vmlinux for dump capture. This option should go away down the
1848           line.
1849 
1850           Don't change this unless you know what you are doing.
1851 
1852 config RELOCATABLE
1853         bool "Build a relocatable kernel"
1854         default y
1855         ---help---
1856           This builds a kernel image that retains relocation information
1857           so it can be loaded someplace besides the default 1MB.
1858           The relocations tend to make the kernel binary about 10% larger,
1859           but are discarded at runtime.
1860 
1861           One use is for the kexec on panic case where the recovery kernel
1862           must live at a different physical address than the primary
1863           kernel.
1864 
1865           Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1866           it has been loaded at and the compile time physical address
1867           (CONFIG_PHYSICAL_START) is used as the minimum location.
1868 
1869 config RANDOMIZE_BASE
1870         bool "Randomize the address of the kernel image"
1871         depends on RELOCATABLE
1872         default n
1873         ---help---
1874            Randomizes the physical and virtual address at which the
1875            kernel image is decompressed, as a security feature that
1876            deters exploit attempts relying on knowledge of the location
1877            of kernel internals.
1878 
1879            Entropy is generated using the RDRAND instruction if it is
1880            supported. If RDTSC is supported, it is used as well. If
1881            neither RDRAND nor RDTSC are supported, then randomness is
1882            read from the i8254 timer.
1883 
1884            The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1885            and aligned according to PHYSICAL_ALIGN. Since the kernel is
1886            built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1887            minimum of 2MiB, only 10 bits of entropy is theoretically
1888            possible. At best, due to page table layouts, 64-bit can use
1889            9 bits of entropy and 32-bit uses 8 bits.
1890 
1891            If unsure, say N.
1892 
1893 config RANDOMIZE_BASE_MAX_OFFSET
1894         hex "Maximum kASLR offset allowed" if EXPERT
1895         depends on RANDOMIZE_BASE
1896         range 0x0 0x20000000 if X86_32
1897         default "0x20000000" if X86_32
1898         range 0x0 0x40000000 if X86_64
1899         default "0x40000000" if X86_64
1900         ---help---
1901           The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1902           memory is used to determine the maximal offset in bytes that will
1903           be applied to the kernel when kernel Address Space Layout
1904           Randomization (kASLR) is active. This must be a multiple of
1905           PHYSICAL_ALIGN.
1906 
1907           On 32-bit this is limited to 512MiB by page table layouts. The
1908           default is 512MiB.
1909 
1910           On 64-bit this is limited by how the kernel fixmap page table is
1911           positioned, so this cannot be larger than 1GiB currently. Without
1912           RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1913           and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1914           modules area will shrink to compensate, up to the current maximum
1915           1GiB to 1GiB split. The default is 1GiB.
1916 
1917           If unsure, leave at the default value.
1918 
1919 # Relocation on x86 needs some additional build support
1920 config X86_NEED_RELOCS
1921         def_bool y
1922         depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1923 
1924 config PHYSICAL_ALIGN
1925         hex "Alignment value to which kernel should be aligned"
1926         default "0x200000"
1927         range 0x2000 0x1000000 if X86_32
1928         range 0x200000 0x1000000 if X86_64
1929         ---help---
1930           This value puts the alignment restrictions on physical address
1931           where kernel is loaded and run from. Kernel is compiled for an
1932           address which meets above alignment restriction.
1933 
1934           If bootloader loads the kernel at a non-aligned address and
1935           CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1936           address aligned to above value and run from there.
1937 
1938           If bootloader loads the kernel at a non-aligned address and
1939           CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1940           load address and decompress itself to the address it has been
1941           compiled for and run from there. The address for which kernel is
1942           compiled already meets above alignment restrictions. Hence the
1943           end result is that kernel runs from a physical address meeting
1944           above alignment restrictions.
1945 
1946           On 32-bit this value must be a multiple of 0x2000. On 64-bit
1947           this value must be a multiple of 0x200000.
1948 
1949           Don't change this unless you know what you are doing.
1950 
1951 config HOTPLUG_CPU
1952         bool "Support for hot-pluggable CPUs"
1953         depends on SMP
1954         ---help---
1955           Say Y here to allow turning CPUs off and on. CPUs can be
1956           controlled through /sys/devices/system/cpu.
1957           ( Note: power management support will enable this option
1958             automatically on SMP systems. )
1959           Say N if you want to disable CPU hotplug.
1960 
1961 config BOOTPARAM_HOTPLUG_CPU0
1962         bool "Set default setting of cpu0_hotpluggable"
1963         default n
1964         depends on HOTPLUG_CPU
1965         ---help---
1966           Set whether default state of cpu0_hotpluggable is on or off.
1967 
1968           Say Y here to enable CPU0 hotplug by default. If this switch
1969           is turned on, there is no need to give cpu0_hotplug kernel
1970           parameter and the CPU0 hotplug feature is enabled by default.
1971 
1972           Please note: there are two known CPU0 dependencies if you want
1973           to enable the CPU0 hotplug feature either by this switch or by
1974           cpu0_hotplug kernel parameter.
1975 
1976           First, resume from hibernate or suspend always starts from CPU0.
1977           So hibernate and suspend are prevented if CPU0 is offline.
1978 
1979           Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1980           offline if any interrupt can not migrate out of CPU0. There may
1981           be other CPU0 dependencies.
1982 
1983           Please make sure the dependencies are under your control before
1984           you enable this feature.
1985 
1986           Say N if you don't want to enable CPU0 hotplug feature by default.
1987           You still can enable the CPU0 hotplug feature at boot by kernel
1988           parameter cpu0_hotplug.
1989 
1990 config DEBUG_HOTPLUG_CPU0
1991         def_bool n
1992         prompt "Debug CPU0 hotplug"
1993         depends on HOTPLUG_CPU
1994         ---help---
1995           Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1996           soon as possible and boots up userspace with CPU0 offlined. User
1997           can online CPU0 back after boot time.
1998 
1999           To debug CPU0 hotplug, you need to enable CPU0 offline/online
2000           feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2001           compilation or giving cpu0_hotplug kernel parameter at boot.
2002 
2003           If unsure, say N.
2004 
2005 config COMPAT_VDSO
2006         def_bool n
2007         prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2008         depends on X86_32 || IA32_EMULATION
2009         ---help---
2010           Certain buggy versions of glibc will crash if they are
2011           presented with a 32-bit vDSO that is not mapped at the address
2012           indicated in its segment table.
2013 
2014           The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2015           and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2016           49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2017           the only released version with the bug, but OpenSUSE 9
2018           contains a buggy "glibc 2.3.2".
2019 
2020           The symptom of the bug is that everything crashes on startup, saying:
2021           dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2022 
2023           Saying Y here changes the default value of the vdso32 boot
2024           option from 1 to 0, which turns off the 32-bit vDSO entirely.
2025           This works around the glibc bug but hurts performance.
2026 
2027           If unsure, say N: if you are compiling your own kernel, you
2028           are unlikely to be using a buggy version of glibc.
2029 
2030 choice
2031         prompt "vsyscall table for legacy applications"
2032         depends on X86_64
2033         default LEGACY_VSYSCALL_EMULATE
2034         help
2035           Legacy user code that does not know how to find the vDSO expects
2036           to be able to issue three syscalls by calling fixed addresses in
2037           kernel space. Since this location is not randomized with ASLR,
2038           it can be used to assist security vulnerability exploitation.
2039 
2040           This setting can be changed at boot time via the kernel command
2041           line parameter vsyscall=[native|emulate|none].
2042 
2043           On a system with recent enough glibc (2.14 or newer) and no
2044           static binaries, you can say None without a performance penalty
2045           to improve security.
2046 
2047           If unsure, select "Emulate".
2048 
2049         config LEGACY_VSYSCALL_NATIVE
2050                 bool "Native"
2051                 help
2052                   Actual executable code is located in the fixed vsyscall
2053                   address mapping, implementing time() efficiently. Since
2054                   this makes the mapping executable, it can be used during
2055                   security vulnerability exploitation (traditionally as
2056                   ROP gadgets). This configuration is not recommended.
2057 
2058         config LEGACY_VSYSCALL_EMULATE
2059                 bool "Emulate"
2060                 help
2061                   The kernel traps and emulates calls into the fixed
2062                   vsyscall address mapping. This makes the mapping
2063                   non-executable, but it still contains known contents,
2064                   which could be used in certain rare security vulnerability
2065                   exploits. This configuration is recommended when userspace
2066                   still uses the vsyscall area.
2067 
2068         config LEGACY_VSYSCALL_NONE
2069                 bool "None"
2070                 help
2071                   There will be no vsyscall mapping at all. This will
2072                   eliminate any risk of ASLR bypass due to the vsyscall
2073                   fixed address mapping. Attempts to use the vsyscalls
2074                   will be reported to dmesg, so that either old or
2075                   malicious userspace programs can be identified.
2076 
2077 endchoice
2078 
2079 config CMDLINE_BOOL
2080         bool "Built-in kernel command line"
2081         ---help---
2082           Allow for specifying boot arguments to the kernel at
2083           build time.  On some systems (e.g. embedded ones), it is
2084           necessary or convenient to provide some or all of the
2085           kernel boot arguments with the kernel itself (that is,
2086           to not rely on the boot loader to provide them.)
2087 
2088           To compile command line arguments into the kernel,
2089           set this option to 'Y', then fill in the
2090           boot arguments in CONFIG_CMDLINE.
2091 
2092           Systems with fully functional boot loaders (i.e. non-embedded)
2093           should leave this option set to 'N'.
2094 
2095 config CMDLINE
2096         string "Built-in kernel command string"
2097         depends on CMDLINE_BOOL
2098         default ""
2099         ---help---
2100           Enter arguments here that should be compiled into the kernel
2101           image and used at boot time.  If the boot loader provides a
2102           command line at boot time, it is appended to this string to
2103           form the full kernel command line, when the system boots.
2104 
2105           However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2106           change this behavior.
2107 
2108           In most cases, the command line (whether built-in or provided
2109           by the boot loader) should specify the device for the root
2110           file system.
2111 
2112 config CMDLINE_OVERRIDE
2113         bool "Built-in command line overrides boot loader arguments"
2114         depends on CMDLINE_BOOL
2115         ---help---
2116           Set this option to 'Y' to have the kernel ignore the boot loader
2117           command line, and use ONLY the built-in command line.
2118 
2119           This is used to work around broken boot loaders.  This should
2120           be set to 'N' under normal conditions.
2121 
2122 config MODIFY_LDT_SYSCALL
2123         bool "Enable the LDT (local descriptor table)" if EXPERT
2124         default y
2125         ---help---
2126           Linux can allow user programs to install a per-process x86
2127           Local Descriptor Table (LDT) using the modify_ldt(2) system
2128           call.  This is required to run 16-bit or segmented code such as
2129           DOSEMU or some Wine programs.  It is also used by some very old
2130           threading libraries.
2131 
2132           Enabling this feature adds a small amount of overhead to
2133           context switches and increases the low-level kernel attack
2134           surface.  Disabling it removes the modify_ldt(2) system call.
2135 
2136           Saying 'N' here may make sense for embedded or server kernels.
2137 
2138 source "kernel/livepatch/Kconfig"
2139 
2140 endmenu
2141 
2142 config ARCH_ENABLE_MEMORY_HOTPLUG
2143         def_bool y
2144         depends on X86_64 || (X86_32 && HIGHMEM)
2145 
2146 config ARCH_ENABLE_MEMORY_HOTREMOVE
2147         def_bool y
2148         depends on MEMORY_HOTPLUG
2149 
2150 config USE_PERCPU_NUMA_NODE_ID
2151         def_bool y
2152         depends on NUMA
2153 
2154 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2155         def_bool y
2156         depends on X86_64 || X86_PAE
2157 
2158 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2159         def_bool y
2160         depends on X86_64 && HUGETLB_PAGE && MIGRATION
2161 
2162 menu "Power management and ACPI options"
2163 
2164 config ARCH_HIBERNATION_HEADER
2165         def_bool y
2166         depends on X86_64 && HIBERNATION
2167 
2168 source "kernel/power/Kconfig"
2169 
2170 source "drivers/acpi/Kconfig"
2171 
2172 source "drivers/sfi/Kconfig"
2173 
2174 config X86_APM_BOOT
2175         def_bool y
2176         depends on APM
2177 
2178 menuconfig APM
2179         tristate "APM (Advanced Power Management) BIOS support"
2180         depends on X86_32 && PM_SLEEP
2181         ---help---
2182           APM is a BIOS specification for saving power using several different
2183           techniques. This is mostly useful for battery powered laptops with
2184           APM compliant BIOSes. If you say Y here, the system time will be
2185           reset after a RESUME operation, the /proc/apm device will provide
2186           battery status information, and user-space programs will receive
2187           notification of APM "events" (e.g. battery status change).
2188 
2189           If you select "Y" here, you can disable actual use of the APM
2190           BIOS by passing the "apm=off" option to the kernel at boot time.
2191 
2192           Note that the APM support is almost completely disabled for
2193           machines with more than one CPU.
2194 
2195           In order to use APM, you will need supporting software. For location
2196           and more information, read <file:Documentation/power/apm-acpi.txt>
2197           and the Battery Powered Linux mini-HOWTO, available from
2198           <http://www.tldp.org/docs.html#howto>.
2199 
2200           This driver does not spin down disk drives (see the hdparm(8)
2201           manpage ("man 8 hdparm") for that), and it doesn't turn off
2202           VESA-compliant "green" monitors.
2203 
2204           This driver does not support the TI 4000M TravelMate and the ACER
2205           486/DX4/75 because they don't have compliant BIOSes. Many "green"
2206           desktop machines also don't have compliant BIOSes, and this driver
2207           may cause those machines to panic during the boot phase.
2208 
2209           Generally, if you don't have a battery in your machine, there isn't
2210           much point in using this driver and you should say N. If you get
2211           random kernel OOPSes or reboots that don't seem to be related to
2212           anything, try disabling/enabling this option (or disabling/enabling
2213           APM in your BIOS).
2214 
2215           Some other things you should try when experiencing seemingly random,
2216           "weird" problems:
2217 
2218           1) make sure that you have enough swap space and that it is
2219           enabled.
2220           2) pass the "no-hlt" option to the kernel
2221           3) switch on floating point emulation in the kernel and pass
2222           the "no387" option to the kernel
2223           4) pass the "floppy=nodma" option to the kernel
2224           5) pass the "mem=4M" option to the kernel (thereby disabling
2225           all but the first 4 MB of RAM)
2226           6) make sure that the CPU is not over clocked.
2227           7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2228           8) disable the cache from your BIOS settings
2229           9) install a fan for the video card or exchange video RAM
2230           10) install a better fan for the CPU
2231           11) exchange RAM chips
2232           12) exchange the motherboard.
2233 
2234           To compile this driver as a module, choose M here: the
2235           module will be called apm.
2236 
2237 if APM
2238 
2239 config APM_IGNORE_USER_SUSPEND
2240         bool "Ignore USER SUSPEND"
2241         ---help---
2242           This option will ignore USER SUSPEND requests. On machines with a
2243           compliant APM BIOS, you want to say N. However, on the NEC Versa M
2244           series notebooks, it is necessary to say Y because of a BIOS bug.
2245 
2246 config APM_DO_ENABLE
2247         bool "Enable PM at boot time"
2248         ---help---
2249           Enable APM features at boot time. From page 36 of the APM BIOS
2250           specification: "When disabled, the APM BIOS does not automatically
2251           power manage devices, enter the Standby State, enter the Suspend
2252           State, or take power saving steps in response to CPU Idle calls."
2253           This driver will make CPU Idle calls when Linux is idle (unless this
2254           feature is turned off -- see "Do CPU IDLE calls", below). This
2255           should always save battery power, but more complicated APM features
2256           will be dependent on your BIOS implementation. You may need to turn
2257           this option off if your computer hangs at boot time when using APM
2258           support, or if it beeps continuously instead of suspending. Turn
2259           this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2260           T400CDT. This is off by default since most machines do fine without
2261           this feature.
2262 
2263 config APM_CPU_IDLE
2264         depends on CPU_IDLE
2265         bool "Make CPU Idle calls when idle"
2266         ---help---
2267           Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2268           On some machines, this can activate improved power savings, such as
2269           a slowed CPU clock rate, when the machine is idle. These idle calls
2270           are made after the idle loop has run for some length of time (e.g.,
2271           333 mS). On some machines, this will cause a hang at boot time or
2272           whenever the CPU becomes idle. (On machines with more than one CPU,
2273           this option does nothing.)
2274 
2275 config APM_DISPLAY_BLANK
2276         bool "Enable console blanking using APM"
2277         ---help---
2278           Enable console blanking using the APM. Some laptops can use this to
2279           turn off the LCD backlight when the screen blanker of the Linux
2280           virtual console blanks the screen. Note that this is only used by
2281           the virtual console screen blanker, and won't turn off the backlight
2282           when using the X Window system. This also doesn't have anything to
2283           do with your VESA-compliant power-saving monitor. Further, this
2284           option doesn't work for all laptops -- it might not turn off your
2285           backlight at all, or it might print a lot of errors to the console,
2286           especially if you are using gpm.
2287 
2288 config APM_ALLOW_INTS
2289         bool "Allow interrupts during APM BIOS calls"
2290         ---help---
2291           Normally we disable external interrupts while we are making calls to
2292           the APM BIOS as a measure to lessen the effects of a badly behaving
2293           BIOS implementation.  The BIOS should reenable interrupts if it
2294           needs to.  Unfortunately, some BIOSes do not -- especially those in
2295           many of the newer IBM Thinkpads.  If you experience hangs when you
2296           suspend, try setting this to Y.  Otherwise, say N.
2297 
2298 endif # APM
2299 
2300 source "drivers/cpufreq/Kconfig"
2301 
2302 source "drivers/cpuidle/Kconfig"
2303 
2304 source "drivers/idle/Kconfig"
2305 
2306 endmenu
2307 
2308 
2309 menu "Bus options (PCI etc.)"
2310 
2311 config PCI
2312         bool "PCI support"
2313         default y
2314         ---help---
2315           Find out whether you have a PCI motherboard. PCI is the name of a
2316           bus system, i.e. the way the CPU talks to the other stuff inside
2317           your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2318           VESA. If you have PCI, say Y, otherwise N.
2319 
2320 choice
2321         prompt "PCI access mode"
2322         depends on X86_32 && PCI
2323         default PCI_GOANY
2324         ---help---
2325           On PCI systems, the BIOS can be used to detect the PCI devices and
2326           determine their configuration. However, some old PCI motherboards
2327           have BIOS bugs and may crash if this is done. Also, some embedded
2328           PCI-based systems don't have any BIOS at all. Linux can also try to
2329           detect the PCI hardware directly without using the BIOS.
2330 
2331           With this option, you can specify how Linux should detect the
2332           PCI devices. If you choose "BIOS", the BIOS will be used,
2333           if you choose "Direct", the BIOS won't be used, and if you
2334           choose "MMConfig", then PCI Express MMCONFIG will be used.
2335           If you choose "Any", the kernel will try MMCONFIG, then the
2336           direct access method and falls back to the BIOS if that doesn't
2337           work. If unsure, go with the default, which is "Any".
2338 
2339 config PCI_GOBIOS
2340         bool "BIOS"
2341 
2342 config PCI_GOMMCONFIG
2343         bool "MMConfig"
2344 
2345 config PCI_GODIRECT
2346         bool "Direct"
2347 
2348 config PCI_GOOLPC
2349         bool "OLPC XO-1"
2350         depends on OLPC
2351 
2352 config PCI_GOANY
2353         bool "Any"
2354 
2355 endchoice
2356 
2357 config PCI_BIOS
2358         def_bool y
2359         depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2360 
2361 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2362 config PCI_DIRECT
2363         def_bool y
2364         depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2365 
2366 config PCI_MMCONFIG
2367         def_bool y
2368         depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2369 
2370 config PCI_OLPC
2371         def_bool y
2372         depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2373 
2374 config PCI_XEN
2375         def_bool y
2376         depends on PCI && XEN
2377         select SWIOTLB_XEN
2378 
2379 config PCI_DOMAINS
2380         def_bool y
2381         depends on PCI
2382 
2383 config PCI_MMCONFIG
2384         bool "Support mmconfig PCI config space access"
2385         depends on X86_64 && PCI && ACPI
2386 
2387 config PCI_CNB20LE_QUIRK
2388         bool "Read CNB20LE Host Bridge Windows" if EXPERT
2389         depends on PCI
2390         help
2391           Read the PCI windows out of the CNB20LE host bridge. This allows
2392           PCI hotplug to work on systems with the CNB20LE chipset which do
2393           not have ACPI.
2394 
2395           There's no public spec for this chipset, and this functionality
2396           is known to be incomplete.
2397 
2398           You should say N unless you know you need this.
2399 
2400 source "drivers/pci/pcie/Kconfig"
2401 
2402 source "drivers/pci/Kconfig"
2403 
2404 # x86_64 have no ISA slots, but can have ISA-style DMA.
2405 config ISA_DMA_API
2406         bool "ISA-style DMA support" if (X86_64 && EXPERT)
2407         default y
2408         help
2409           Enables ISA-style DMA support for devices requiring such controllers.
2410           If unsure, say Y.
2411 
2412 if X86_32
2413 
2414 config ISA
2415         bool "ISA support"
2416         ---help---
2417           Find out whether you have ISA slots on your motherboard.  ISA is the
2418           name of a bus system, i.e. the way the CPU talks to the other stuff
2419           inside your box.  Other bus systems are PCI, EISA, MicroChannel
2420           (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2421           newer boards don't support it.  If you have ISA, say Y, otherwise N.
2422 
2423 config EISA
2424         bool "EISA support"
2425         depends on ISA
2426         ---help---
2427           The Extended Industry Standard Architecture (EISA) bus was
2428           developed as an open alternative to the IBM MicroChannel bus.
2429 
2430           The EISA bus provided some of the features of the IBM MicroChannel
2431           bus while maintaining backward compatibility with cards made for
2432           the older ISA bus.  The EISA bus saw limited use between 1988 and
2433           1995 when it was made obsolete by the PCI bus.
2434 
2435           Say Y here if you are building a kernel for an EISA-based machine.
2436 
2437           Otherwise, say N.
2438 
2439 source "drivers/eisa/Kconfig"
2440 
2441 config SCx200
2442         tristate "NatSemi SCx200 support"
2443         ---help---
2444           This provides basic support for National Semiconductor's
2445           (now AMD's) Geode processors.  The driver probes for the
2446           PCI-IDs of several on-chip devices, so its a good dependency
2447           for other scx200_* drivers.
2448 
2449           If compiled as a module, the driver is named scx200.
2450 
2451 config SCx200HR_TIMER
2452         tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2453         depends on SCx200
2454         default y
2455         ---help---
2456           This driver provides a clocksource built upon the on-chip
2457           27MHz high-resolution timer.  Its also a workaround for
2458           NSC Geode SC-1100's buggy TSC, which loses time when the
2459           processor goes idle (as is done by the scheduler).  The
2460           other workaround is idle=poll boot option.
2461 
2462 config OLPC
2463         bool "One Laptop Per Child support"
2464         depends on !X86_PAE
2465         select GPIOLIB
2466         select OF
2467         select OF_PROMTREE
2468         select IRQ_DOMAIN
2469         ---help---
2470           Add support for detecting the unique features of the OLPC
2471           XO hardware.
2472 
2473 config OLPC_XO1_PM
2474         bool "OLPC XO-1 Power Management"
2475         depends on OLPC && MFD_CS5535 && PM_SLEEP
2476         select MFD_CORE
2477         ---help---
2478           Add support for poweroff and suspend of the OLPC XO-1 laptop.
2479 
2480 config OLPC_XO1_RTC
2481         bool "OLPC XO-1 Real Time Clock"
2482         depends on OLPC_XO1_PM && RTC_DRV_CMOS
2483         ---help---
2484           Add support for the XO-1 real time clock, which can be used as a
2485           programmable wakeup source.
2486 
2487 config OLPC_XO1_SCI
2488         bool "OLPC XO-1 SCI extras"
2489         depends on OLPC && OLPC_XO1_PM
2490         depends on INPUT=y
2491         select POWER_SUPPLY
2492         select GPIO_CS5535
2493         select MFD_CORE
2494         ---help---
2495           Add support for SCI-based features of the OLPC XO-1 laptop:
2496            - EC-driven system wakeups
2497            - Power button
2498            - Ebook switch
2499            - Lid switch
2500            - AC adapter status updates
2501            - Battery status updates
2502 
2503 config OLPC_XO15_SCI
2504         bool "OLPC XO-1.5 SCI extras"
2505         depends on OLPC && ACPI
2506         select POWER_SUPPLY
2507         ---help---
2508           Add support for SCI-based features of the OLPC XO-1.5 laptop:
2509            - EC-driven system wakeups
2510            - AC adapter status updates
2511            - Battery status updates
2512 
2513 config ALIX
2514         bool "PCEngines ALIX System Support (LED setup)"
2515         select GPIOLIB
2516         ---help---
2517           This option enables system support for the PCEngines ALIX.
2518           At present this just sets up LEDs for GPIO control on
2519           ALIX2/3/6 boards.  However, other system specific setup should
2520           get added here.
2521 
2522           Note: You must still enable the drivers for GPIO and LED support
2523           (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2524 
2525           Note: You have to set alix.force=1 for boards with Award BIOS.
2526 
2527 config NET5501
2528         bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2529         select GPIOLIB
2530         ---help---
2531           This option enables system support for the Soekris Engineering net5501.
2532 
2533 config GEOS
2534         bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2535         select GPIOLIB
2536         depends on DMI
2537         ---help---
2538           This option enables system support for the Traverse Technologies GEOS.
2539 
2540 config TS5500
2541         bool "Technologic Systems TS-5500 platform support"
2542         depends on MELAN
2543         select CHECK_SIGNATURE
2544         select NEW_LEDS
2545         select LEDS_CLASS
2546         ---help---
2547           This option enables system support for the Technologic Systems TS-5500.
2548 
2549 endif # X86_32
2550 
2551 config AMD_NB
2552         def_bool y
2553         depends on CPU_SUP_AMD && PCI
2554 
2555 source "drivers/pcmcia/Kconfig"
2556 
2557 source "drivers/pci/hotplug/Kconfig"
2558 
2559 config RAPIDIO
2560         tristate "RapidIO support"
2561         depends on PCI
2562         default n
2563         help
2564           If enabled this option will include drivers and the core
2565           infrastructure code to support RapidIO interconnect devices.
2566 
2567 source "drivers/rapidio/Kconfig"
2568 
2569 config X86_SYSFB
2570         bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2571         help
2572           Firmwares often provide initial graphics framebuffers so the BIOS,
2573           bootloader or kernel can show basic video-output during boot for
2574           user-guidance and debugging. Historically, x86 used the VESA BIOS
2575           Extensions and EFI-framebuffers for this, which are mostly limited
2576           to x86.
2577           This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2578           framebuffers so the new generic system-framebuffer drivers can be
2579           used on x86. If the framebuffer is not compatible with the generic
2580           modes, it is adverticed as fallback platform framebuffer so legacy
2581           drivers like efifb, vesafb and uvesafb can pick it up.
2582           If this option is not selected, all system framebuffers are always
2583           marked as fallback platform framebuffers as usual.
2584 
2585           Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2586           not be able to pick up generic system framebuffers if this option
2587           is selected. You are highly encouraged to enable simplefb as
2588           replacement if you select this option. simplefb can correctly deal
2589           with generic system framebuffers. But you should still keep vesafb
2590           and others enabled as fallback if a system framebuffer is
2591           incompatible with simplefb.
2592 
2593           If unsure, say Y.
2594 
2595 endmenu
2596 
2597 
2598 menu "Executable file formats / Emulations"
2599 
2600 source "fs/Kconfig.binfmt"
2601 
2602 config IA32_EMULATION
2603         bool "IA32 Emulation"
2604         depends on X86_64
2605         select BINFMT_ELF
2606         select COMPAT_BINFMT_ELF
2607         select ARCH_WANT_OLD_COMPAT_IPC
2608         ---help---
2609           Include code to run legacy 32-bit programs under a
2610           64-bit kernel. You should likely turn this on, unless you're
2611           100% sure that you don't have any 32-bit programs left.
2612 
2613 config IA32_AOUT
2614         tristate "IA32 a.out support"
2615         depends on IA32_EMULATION
2616         ---help---
2617           Support old a.out binaries in the 32bit emulation.
2618 
2619 config X86_X32
2620         bool "x32 ABI for 64-bit mode"
2621         depends on X86_64
2622         ---help---
2623           Include code to run binaries for the x32 native 32-bit ABI
2624           for 64-bit processors.  An x32 process gets access to the
2625           full 64-bit register file and wide data path while leaving
2626           pointers at 32 bits for smaller memory footprint.
2627 
2628           You will need a recent binutils (2.22 or later) with
2629           elf32_x86_64 support enabled to compile a kernel with this
2630           option set.
2631 
2632 config COMPAT
2633         def_bool y
2634         depends on IA32_EMULATION || X86_X32
2635 
2636 if COMPAT
2637 config COMPAT_FOR_U64_ALIGNMENT
2638         def_bool y
2639 
2640 config SYSVIPC_COMPAT
2641         def_bool y
2642         depends on SYSVIPC
2643 
2644 config KEYS_COMPAT
2645         def_bool y
2646         depends on KEYS
2647 endif
2648 
2649 endmenu
2650 
2651 
2652 config HAVE_ATOMIC_IOMAP
2653         def_bool y
2654         depends on X86_32
2655 
2656 config X86_DEV_DMA_OPS
2657         bool
2658         depends on X86_64 || STA2X11
2659 
2660 config X86_DMA_REMAP
2661         bool
2662         depends on STA2X11
2663 
2664 config PMC_ATOM
2665         def_bool y
2666         depends on PCI
2667 
2668 source "net/Kconfig"
2669 
2670 source "drivers/Kconfig"
2671 
2672 source "drivers/firmware/Kconfig"
2673 
2674 source "fs/Kconfig"
2675 
2676 source "arch/x86/Kconfig.debug"
2677 
2678 source "security/Kconfig"
2679 
2680 source "crypto/Kconfig"
2681 
2682 source "arch/x86/kvm/Kconfig"
2683 
2684 source "lib/Kconfig"

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