Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm
[deliverable/linux.git] / arch / x86 / Kconfig
1 # Select 32 or 64 bit
2 config 64BIT
3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH != "i386"
5 ---help---
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
8
9 config X86_32
10 def_bool y
11 depends on !64BIT
12
13 config X86_64
14 def_bool y
15 depends on 64BIT
16
17 ### Arch settings
18 config X86
19 def_bool y
20 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
21 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
22 select ANON_INODES
23 select ARCH_CLOCKSOURCE_DATA
24 select ARCH_DISCARD_MEMBLOCK
25 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
26 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
27 select ARCH_HAS_DEVMEM_IS_ALLOWED
28 select ARCH_HAS_ELF_RANDOMIZE
29 select ARCH_HAS_FAST_MULTIPLIER
30 select ARCH_HAS_GCOV_PROFILE_ALL
31 select ARCH_HAS_KCOV if X86_64
32 select ARCH_HAS_PMEM_API if X86_64
33 select ARCH_HAS_MMIO_FLUSH
34 select ARCH_HAS_SG_CHAIN
35 select ARCH_HAS_UBSAN_SANITIZE_ALL
36 select ARCH_HAVE_NMI_SAFE_CMPXCHG
37 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
38 select ARCH_MIGHT_HAVE_PC_PARPORT
39 select ARCH_MIGHT_HAVE_PC_SERIO
40 select ARCH_SUPPORTS_ATOMIC_RMW
41 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
42 select ARCH_SUPPORTS_INT128 if X86_64
43 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
44 select ARCH_USE_BUILTIN_BSWAP
45 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
46 select ARCH_USE_QUEUED_RWLOCKS
47 select ARCH_USE_QUEUED_SPINLOCKS
48 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
49 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
50 select ARCH_WANT_FRAME_POINTERS
51 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
52 select BUILDTIME_EXTABLE_SORT
53 select CLKEVT_I8253
54 select CLKSRC_I8253 if X86_32
55 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
56 select CLOCKSOURCE_WATCHDOG
57 select CLONE_BACKWARDS if X86_32
58 select COMPAT_OLD_SIGACTION if IA32_EMULATION
59 select DCACHE_WORD_ACCESS
60 select EDAC_ATOMIC_SCRUB
61 select EDAC_SUPPORT
62 select GENERIC_CLOCKEVENTS
63 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
64 select GENERIC_CLOCKEVENTS_MIN_ADJUST
65 select GENERIC_CMOS_UPDATE
66 select GENERIC_CPU_AUTOPROBE
67 select GENERIC_EARLY_IOREMAP
68 select GENERIC_FIND_FIRST_BIT
69 select GENERIC_IOMAP
70 select GENERIC_IRQ_PROBE
71 select GENERIC_IRQ_SHOW
72 select GENERIC_PENDING_IRQ if SMP
73 select GENERIC_SMP_IDLE_THREAD
74 select GENERIC_STRNCPY_FROM_USER
75 select GENERIC_STRNLEN_USER
76 select GENERIC_TIME_VSYSCALL
77 select HAVE_ACPI_APEI if ACPI
78 select HAVE_ACPI_APEI_NMI if ACPI
79 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
80 select HAVE_AOUT if X86_32
81 select HAVE_ARCH_AUDITSYSCALL
82 select HAVE_ARCH_HARDENED_USERCOPY
83 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
84 select HAVE_ARCH_JUMP_LABEL
85 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
86 select HAVE_ARCH_KGDB
87 select HAVE_ARCH_KMEMCHECK
88 select HAVE_ARCH_MMAP_RND_BITS if MMU
89 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
90 select HAVE_ARCH_SECCOMP_FILTER
91 select HAVE_ARCH_SOFT_DIRTY if X86_64
92 select HAVE_ARCH_TRACEHOOK
93 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
94 select HAVE_ARCH_WITHIN_STACK_FRAMES
95 select HAVE_EBPF_JIT if X86_64
96 select HAVE_CC_STACKPROTECTOR
97 select HAVE_CMPXCHG_DOUBLE
98 select HAVE_CMPXCHG_LOCAL
99 select HAVE_CONTEXT_TRACKING if X86_64
100 select HAVE_COPY_THREAD_TLS
101 select HAVE_C_RECORDMCOUNT
102 select HAVE_DEBUG_KMEMLEAK
103 select HAVE_DEBUG_STACKOVERFLOW
104 select HAVE_DMA_API_DEBUG
105 select HAVE_DMA_CONTIGUOUS
106 select HAVE_DYNAMIC_FTRACE
107 select HAVE_DYNAMIC_FTRACE_WITH_REGS
108 select HAVE_EFFICIENT_UNALIGNED_ACCESS
109 select HAVE_EXIT_THREAD
110 select HAVE_FENTRY if X86_64
111 select HAVE_FTRACE_MCOUNT_RECORD
112 select HAVE_FUNCTION_GRAPH_FP_TEST
113 select HAVE_FUNCTION_GRAPH_TRACER
114 select HAVE_FUNCTION_TRACER
115 select HAVE_GCC_PLUGINS
116 select HAVE_GENERIC_DMA_COHERENT if X86_32
117 select HAVE_HW_BREAKPOINT
118 select HAVE_IDE
119 select HAVE_IOREMAP_PROT
120 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
121 select HAVE_IRQ_TIME_ACCOUNTING
122 select HAVE_KERNEL_BZIP2
123 select HAVE_KERNEL_GZIP
124 select HAVE_KERNEL_LZ4
125 select HAVE_KERNEL_LZMA
126 select HAVE_KERNEL_LZO
127 select HAVE_KERNEL_XZ
128 select HAVE_KPROBES
129 select HAVE_KPROBES_ON_FTRACE
130 select HAVE_KRETPROBES
131 select HAVE_KVM
132 select HAVE_LIVEPATCH if X86_64
133 select HAVE_MEMBLOCK
134 select HAVE_MEMBLOCK_NODE_MAP
135 select HAVE_MIXED_BREAKPOINTS_REGS
136 select HAVE_NMI
137 select HAVE_OPROFILE
138 select HAVE_OPTPROBES
139 select HAVE_PCSPKR_PLATFORM
140 select HAVE_PERF_EVENTS
141 select HAVE_PERF_EVENTS_NMI
142 select HAVE_PERF_REGS
143 select HAVE_PERF_USER_STACK_DUMP
144 select HAVE_REGS_AND_STACK_ACCESS_API
145 select HAVE_SYSCALL_TRACEPOINTS
146 select HAVE_UID16 if X86_32 || IA32_EMULATION
147 select HAVE_UNSTABLE_SCHED_CLOCK
148 select HAVE_USER_RETURN_NOTIFIER
149 select IRQ_FORCED_THREADING
150 select MODULES_USE_ELF_RELA if X86_64
151 select MODULES_USE_ELF_REL if X86_32
152 select OLD_SIGACTION if X86_32
153 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
154 select PERF_EVENTS
155 select RTC_LIB
156 select RTC_MC146818_LIB
157 select SPARSE_IRQ
158 select SRCU
159 select SYSCTL_EXCEPTION_TRACE
160 select USER_STACKTRACE_SUPPORT
161 select VIRT_TO_BUS
162 select X86_DEV_DMA_OPS if X86_64
163 select X86_FEATURE_NAMES if PROC_FS
164 select HAVE_STACK_VALIDATION if X86_64
165 select ARCH_USES_HIGH_VMA_FLAGS if X86_INTEL_MEMORY_PROTECTION_KEYS
166 select ARCH_HAS_PKEYS if X86_INTEL_MEMORY_PROTECTION_KEYS
167
168 config INSTRUCTION_DECODER
169 def_bool y
170 depends on KPROBES || PERF_EVENTS || UPROBES
171
172 config OUTPUT_FORMAT
173 string
174 default "elf32-i386" if X86_32
175 default "elf64-x86-64" if X86_64
176
177 config ARCH_DEFCONFIG
178 string
179 default "arch/x86/configs/i386_defconfig" if X86_32
180 default "arch/x86/configs/x86_64_defconfig" if X86_64
181
182 config LOCKDEP_SUPPORT
183 def_bool y
184
185 config STACKTRACE_SUPPORT
186 def_bool y
187
188 config MMU
189 def_bool y
190
191 config ARCH_MMAP_RND_BITS_MIN
192 default 28 if 64BIT
193 default 8
194
195 config ARCH_MMAP_RND_BITS_MAX
196 default 32 if 64BIT
197 default 16
198
199 config ARCH_MMAP_RND_COMPAT_BITS_MIN
200 default 8
201
202 config ARCH_MMAP_RND_COMPAT_BITS_MAX
203 default 16
204
205 config SBUS
206 bool
207
208 config NEED_DMA_MAP_STATE
209 def_bool y
210 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
211
212 config NEED_SG_DMA_LENGTH
213 def_bool y
214
215 config GENERIC_ISA_DMA
216 def_bool y
217 depends on ISA_DMA_API
218
219 config GENERIC_BUG
220 def_bool y
221 depends on BUG
222 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
223
224 config GENERIC_BUG_RELATIVE_POINTERS
225 bool
226
227 config GENERIC_HWEIGHT
228 def_bool y
229
230 config ARCH_MAY_HAVE_PC_FDC
231 def_bool y
232 depends on ISA_DMA_API
233
234 config RWSEM_XCHGADD_ALGORITHM
235 def_bool y
236
237 config GENERIC_CALIBRATE_DELAY
238 def_bool y
239
240 config ARCH_HAS_CPU_RELAX
241 def_bool y
242
243 config ARCH_HAS_CACHE_LINE_SIZE
244 def_bool y
245
246 config HAVE_SETUP_PER_CPU_AREA
247 def_bool y
248
249 config NEED_PER_CPU_EMBED_FIRST_CHUNK
250 def_bool y
251
252 config NEED_PER_CPU_PAGE_FIRST_CHUNK
253 def_bool y
254
255 config ARCH_HIBERNATION_POSSIBLE
256 def_bool y
257
258 config ARCH_SUSPEND_POSSIBLE
259 def_bool y
260
261 config ARCH_WANT_HUGE_PMD_SHARE
262 def_bool y
263
264 config ARCH_WANT_GENERAL_HUGETLB
265 def_bool y
266
267 config ZONE_DMA32
268 def_bool y if X86_64
269
270 config AUDIT_ARCH
271 def_bool y if X86_64
272
273 config ARCH_SUPPORTS_OPTIMIZED_INLINING
274 def_bool y
275
276 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
277 def_bool y
278
279 config KASAN_SHADOW_OFFSET
280 hex
281 depends on KASAN
282 default 0xdffffc0000000000
283
284 config HAVE_INTEL_TXT
285 def_bool y
286 depends on INTEL_IOMMU && ACPI
287
288 config X86_32_SMP
289 def_bool y
290 depends on X86_32 && SMP
291
292 config X86_64_SMP
293 def_bool y
294 depends on X86_64 && SMP
295
296 config X86_32_LAZY_GS
297 def_bool y
298 depends on X86_32 && !CC_STACKPROTECTOR
299
300 config ARCH_SUPPORTS_UPROBES
301 def_bool y
302
303 config FIX_EARLYCON_MEM
304 def_bool y
305
306 config DEBUG_RODATA
307 def_bool y
308
309 config PGTABLE_LEVELS
310 int
311 default 4 if X86_64
312 default 3 if X86_PAE
313 default 2
314
315 source "init/Kconfig"
316 source "kernel/Kconfig.freezer"
317
318 menu "Processor type and features"
319
320 config ZONE_DMA
321 bool "DMA memory allocation support" if EXPERT
322 default y
323 help
324 DMA memory allocation support allows devices with less than 32-bit
325 addressing to allocate within the first 16MB of address space.
326 Disable if no such devices will be used.
327
328 If unsure, say Y.
329
330 config SMP
331 bool "Symmetric multi-processing support"
332 ---help---
333 This enables support for systems with more than one CPU. If you have
334 a system with only one CPU, say N. If you have a system with more
335 than one CPU, say Y.
336
337 If you say N here, the kernel will run on uni- and multiprocessor
338 machines, but will use only one CPU of a multiprocessor machine. If
339 you say Y here, the kernel will run on many, but not all,
340 uniprocessor machines. On a uniprocessor machine, the kernel
341 will run faster if you say N here.
342
343 Note that if you say Y here and choose architecture "586" or
344 "Pentium" under "Processor family", the kernel will not work on 486
345 architectures. Similarly, multiprocessor kernels for the "PPro"
346 architecture may not work on all Pentium based boards.
347
348 People using multiprocessor machines who say Y here should also say
349 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
350 Management" code will be disabled if you say Y here.
351
352 See also <file:Documentation/x86/i386/IO-APIC.txt>,
353 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
354 <http://www.tldp.org/docs.html#howto>.
355
356 If you don't know what to do here, say N.
357
358 config X86_FEATURE_NAMES
359 bool "Processor feature human-readable names" if EMBEDDED
360 default y
361 ---help---
362 This option compiles in a table of x86 feature bits and corresponding
363 names. This is required to support /proc/cpuinfo and a few kernel
364 messages. You can disable this to save space, at the expense of
365 making those few kernel messages show numeric feature bits instead.
366
367 If in doubt, say Y.
368
369 config X86_FAST_FEATURE_TESTS
370 bool "Fast CPU feature tests" if EMBEDDED
371 default y
372 ---help---
373 Some fast-paths in the kernel depend on the capabilities of the CPU.
374 Say Y here for the kernel to patch in the appropriate code at runtime
375 based on the capabilities of the CPU. The infrastructure for patching
376 code at runtime takes up some additional space; space-constrained
377 embedded systems may wish to say N here to produce smaller, slightly
378 slower code.
379
380 config X86_X2APIC
381 bool "Support x2apic"
382 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
383 ---help---
384 This enables x2apic support on CPUs that have this feature.
385
386 This allows 32-bit apic IDs (so it can support very large systems),
387 and accesses the local apic via MSRs not via mmio.
388
389 If you don't know what to do here, say N.
390
391 config X86_MPPARSE
392 bool "Enable MPS table" if ACPI || SFI
393 default y
394 depends on X86_LOCAL_APIC
395 ---help---
396 For old smp systems that do not have proper acpi support. Newer systems
397 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
398
399 config X86_BIGSMP
400 bool "Support for big SMP systems with more than 8 CPUs"
401 depends on X86_32 && SMP
402 ---help---
403 This option is needed for the systems that have more than 8 CPUs
404
405 config GOLDFISH
406 def_bool y
407 depends on X86_GOLDFISH
408
409 if X86_32
410 config X86_EXTENDED_PLATFORM
411 bool "Support for extended (non-PC) x86 platforms"
412 default y
413 ---help---
414 If you disable this option then the kernel will only support
415 standard PC platforms. (which covers the vast majority of
416 systems out there.)
417
418 If you enable this option then you'll be able to select support
419 for the following (non-PC) 32 bit x86 platforms:
420 Goldfish (Android emulator)
421 AMD Elan
422 RDC R-321x SoC
423 SGI 320/540 (Visual Workstation)
424 STA2X11-based (e.g. Northville)
425 Moorestown MID devices
426
427 If you have one of these systems, or if you want to build a
428 generic distribution kernel, say Y here - otherwise say N.
429 endif
430
431 if X86_64
432 config X86_EXTENDED_PLATFORM
433 bool "Support for extended (non-PC) x86 platforms"
434 default y
435 ---help---
436 If you disable this option then the kernel will only support
437 standard PC platforms. (which covers the vast majority of
438 systems out there.)
439
440 If you enable this option then you'll be able to select support
441 for the following (non-PC) 64 bit x86 platforms:
442 Numascale NumaChip
443 ScaleMP vSMP
444 SGI Ultraviolet
445
446 If you have one of these systems, or if you want to build a
447 generic distribution kernel, say Y here - otherwise say N.
448 endif
449 # This is an alphabetically sorted list of 64 bit extended platforms
450 # Please maintain the alphabetic order if and when there are additions
451 config X86_NUMACHIP
452 bool "Numascale NumaChip"
453 depends on X86_64
454 depends on X86_EXTENDED_PLATFORM
455 depends on NUMA
456 depends on SMP
457 depends on X86_X2APIC
458 depends on PCI_MMCONFIG
459 ---help---
460 Adds support for Numascale NumaChip large-SMP systems. Needed to
461 enable more than ~168 cores.
462 If you don't have one of these, you should say N here.
463
464 config X86_VSMP
465 bool "ScaleMP vSMP"
466 select HYPERVISOR_GUEST
467 select PARAVIRT
468 depends on X86_64 && PCI
469 depends on X86_EXTENDED_PLATFORM
470 depends on SMP
471 ---help---
472 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
473 supposed to run on these EM64T-based machines. Only choose this option
474 if you have one of these machines.
475
476 config X86_UV
477 bool "SGI Ultraviolet"
478 depends on X86_64
479 depends on X86_EXTENDED_PLATFORM
480 depends on NUMA
481 depends on EFI
482 depends on X86_X2APIC
483 depends on PCI
484 ---help---
485 This option is needed in order to support SGI Ultraviolet systems.
486 If you don't have one of these, you should say N here.
487
488 # Following is an alphabetically sorted list of 32 bit extended platforms
489 # Please maintain the alphabetic order if and when there are additions
490
491 config X86_GOLDFISH
492 bool "Goldfish (Virtual Platform)"
493 depends on X86_EXTENDED_PLATFORM
494 ---help---
495 Enable support for the Goldfish virtual platform used primarily
496 for Android development. Unless you are building for the Android
497 Goldfish emulator say N here.
498
499 config X86_INTEL_CE
500 bool "CE4100 TV platform"
501 depends on PCI
502 depends on PCI_GODIRECT
503 depends on X86_IO_APIC
504 depends on X86_32
505 depends on X86_EXTENDED_PLATFORM
506 select X86_REBOOTFIXUPS
507 select OF
508 select OF_EARLY_FLATTREE
509 ---help---
510 Select for the Intel CE media processor (CE4100) SOC.
511 This option compiles in support for the CE4100 SOC for settop
512 boxes and media devices.
513
514 config X86_INTEL_MID
515 bool "Intel MID platform support"
516 depends on X86_EXTENDED_PLATFORM
517 depends on X86_PLATFORM_DEVICES
518 depends on PCI
519 depends on X86_64 || (PCI_GOANY && X86_32)
520 depends on X86_IO_APIC
521 select SFI
522 select I2C
523 select DW_APB_TIMER
524 select APB_TIMER
525 select INTEL_SCU_IPC
526 select MFD_INTEL_MSIC
527 ---help---
528 Select to build a kernel capable of supporting Intel MID (Mobile
529 Internet Device) platform systems which do not have the PCI legacy
530 interfaces. If you are building for a PC class system say N here.
531
532 Intel MID platforms are based on an Intel processor and chipset which
533 consume less power than most of the x86 derivatives.
534
535 config X86_INTEL_QUARK
536 bool "Intel Quark platform support"
537 depends on X86_32
538 depends on X86_EXTENDED_PLATFORM
539 depends on X86_PLATFORM_DEVICES
540 depends on X86_TSC
541 depends on PCI
542 depends on PCI_GOANY
543 depends on X86_IO_APIC
544 select IOSF_MBI
545 select INTEL_IMR
546 select COMMON_CLK
547 ---help---
548 Select to include support for Quark X1000 SoC.
549 Say Y here if you have a Quark based system such as the Arduino
550 compatible Intel Galileo.
551
552 config X86_INTEL_LPSS
553 bool "Intel Low Power Subsystem Support"
554 depends on X86 && ACPI
555 select COMMON_CLK
556 select PINCTRL
557 select IOSF_MBI
558 ---help---
559 Select to build support for Intel Low Power Subsystem such as
560 found on Intel Lynxpoint PCH. Selecting this option enables
561 things like clock tree (common clock framework) and pincontrol
562 which are needed by the LPSS peripheral drivers.
563
564 config X86_AMD_PLATFORM_DEVICE
565 bool "AMD ACPI2Platform devices support"
566 depends on ACPI
567 select COMMON_CLK
568 select PINCTRL
569 ---help---
570 Select to interpret AMD specific ACPI device to platform device
571 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
572 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
573 implemented under PINCTRL subsystem.
574
575 config IOSF_MBI
576 tristate "Intel SoC IOSF Sideband support for SoC platforms"
577 depends on PCI
578 ---help---
579 This option enables sideband register access support for Intel SoC
580 platforms. On these platforms the IOSF sideband is used in lieu of
581 MSR's for some register accesses, mostly but not limited to thermal
582 and power. Drivers may query the availability of this device to
583 determine if they need the sideband in order to work on these
584 platforms. The sideband is available on the following SoC products.
585 This list is not meant to be exclusive.
586 - BayTrail
587 - Braswell
588 - Quark
589
590 You should say Y if you are running a kernel on one of these SoC's.
591
592 config IOSF_MBI_DEBUG
593 bool "Enable IOSF sideband access through debugfs"
594 depends on IOSF_MBI && DEBUG_FS
595 ---help---
596 Select this option to expose the IOSF sideband access registers (MCR,
597 MDR, MCRX) through debugfs to write and read register information from
598 different units on the SoC. This is most useful for obtaining device
599 state information for debug and analysis. As this is a general access
600 mechanism, users of this option would have specific knowledge of the
601 device they want to access.
602
603 If you don't require the option or are in doubt, say N.
604
605 config X86_RDC321X
606 bool "RDC R-321x SoC"
607 depends on X86_32
608 depends on X86_EXTENDED_PLATFORM
609 select M486
610 select X86_REBOOTFIXUPS
611 ---help---
612 This option is needed for RDC R-321x system-on-chip, also known
613 as R-8610-(G).
614 If you don't have one of these chips, you should say N here.
615
616 config X86_32_NON_STANDARD
617 bool "Support non-standard 32-bit SMP architectures"
618 depends on X86_32 && SMP
619 depends on X86_EXTENDED_PLATFORM
620 ---help---
621 This option compiles in the bigsmp and STA2X11 default
622 subarchitectures. It is intended for a generic binary
623 kernel. If you select them all, kernel will probe it one by
624 one and will fallback to default.
625
626 # Alphabetically sorted list of Non standard 32 bit platforms
627
628 config X86_SUPPORTS_MEMORY_FAILURE
629 def_bool y
630 # MCE code calls memory_failure():
631 depends on X86_MCE
632 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
633 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
634 depends on X86_64 || !SPARSEMEM
635 select ARCH_SUPPORTS_MEMORY_FAILURE
636
637 config STA2X11
638 bool "STA2X11 Companion Chip Support"
639 depends on X86_32_NON_STANDARD && PCI
640 select X86_DEV_DMA_OPS
641 select X86_DMA_REMAP
642 select SWIOTLB
643 select MFD_STA2X11
644 select GPIOLIB
645 default n
646 ---help---
647 This adds support for boards based on the STA2X11 IO-Hub,
648 a.k.a. "ConneXt". The chip is used in place of the standard
649 PC chipset, so all "standard" peripherals are missing. If this
650 option is selected the kernel will still be able to boot on
651 standard PC machines.
652
653 config X86_32_IRIS
654 tristate "Eurobraille/Iris poweroff module"
655 depends on X86_32
656 ---help---
657 The Iris machines from EuroBraille do not have APM or ACPI support
658 to shut themselves down properly. A special I/O sequence is
659 needed to do so, which is what this module does at
660 kernel shutdown.
661
662 This is only for Iris machines from EuroBraille.
663
664 If unused, say N.
665
666 config SCHED_OMIT_FRAME_POINTER
667 def_bool y
668 prompt "Single-depth WCHAN output"
669 depends on X86
670 ---help---
671 Calculate simpler /proc/<PID>/wchan values. If this option
672 is disabled then wchan values will recurse back to the
673 caller function. This provides more accurate wchan values,
674 at the expense of slightly more scheduling overhead.
675
676 If in doubt, say "Y".
677
678 menuconfig HYPERVISOR_GUEST
679 bool "Linux guest support"
680 ---help---
681 Say Y here to enable options for running Linux under various hyper-
682 visors. This option enables basic hypervisor detection and platform
683 setup.
684
685 If you say N, all options in this submenu will be skipped and
686 disabled, and Linux guest support won't be built in.
687
688 if HYPERVISOR_GUEST
689
690 config PARAVIRT
691 bool "Enable paravirtualization code"
692 ---help---
693 This changes the kernel so it can modify itself when it is run
694 under a hypervisor, potentially improving performance significantly
695 over full virtualization. However, when run without a hypervisor
696 the kernel is theoretically slower and slightly larger.
697
698 config PARAVIRT_DEBUG
699 bool "paravirt-ops debugging"
700 depends on PARAVIRT && DEBUG_KERNEL
701 ---help---
702 Enable to debug paravirt_ops internals. Specifically, BUG if
703 a paravirt_op is missing when it is called.
704
705 config PARAVIRT_SPINLOCKS
706 bool "Paravirtualization layer for spinlocks"
707 depends on PARAVIRT && SMP
708 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
709 ---help---
710 Paravirtualized spinlocks allow a pvops backend to replace the
711 spinlock implementation with something virtualization-friendly
712 (for example, block the virtual CPU rather than spinning).
713
714 It has a minimal impact on native kernels and gives a nice performance
715 benefit on paravirtualized KVM / Xen kernels.
716
717 If you are unsure how to answer this question, answer Y.
718
719 config QUEUED_LOCK_STAT
720 bool "Paravirt queued spinlock statistics"
721 depends on PARAVIRT_SPINLOCKS && DEBUG_FS && QUEUED_SPINLOCKS
722 ---help---
723 Enable the collection of statistical data on the slowpath
724 behavior of paravirtualized queued spinlocks and report
725 them on debugfs.
726
727 source "arch/x86/xen/Kconfig"
728
729 config KVM_GUEST
730 bool "KVM Guest support (including kvmclock)"
731 depends on PARAVIRT
732 select PARAVIRT_CLOCK
733 default y
734 ---help---
735 This option enables various optimizations for running under the KVM
736 hypervisor. It includes a paravirtualized clock, so that instead
737 of relying on a PIT (or probably other) emulation by the
738 underlying device model, the host provides the guest with
739 timing infrastructure such as time of day, and system time
740
741 config KVM_DEBUG_FS
742 bool "Enable debug information for KVM Guests in debugfs"
743 depends on KVM_GUEST && DEBUG_FS
744 default n
745 ---help---
746 This option enables collection of various statistics for KVM guest.
747 Statistics are displayed in debugfs filesystem. Enabling this option
748 may incur significant overhead.
749
750 source "arch/x86/lguest/Kconfig"
751
752 config PARAVIRT_TIME_ACCOUNTING
753 bool "Paravirtual steal time accounting"
754 depends on PARAVIRT
755 default n
756 ---help---
757 Select this option to enable fine granularity task steal time
758 accounting. Time spent executing other tasks in parallel with
759 the current vCPU is discounted from the vCPU power. To account for
760 that, there can be a small performance impact.
761
762 If in doubt, say N here.
763
764 config PARAVIRT_CLOCK
765 bool
766
767 endif #HYPERVISOR_GUEST
768
769 config NO_BOOTMEM
770 def_bool y
771
772 source "arch/x86/Kconfig.cpu"
773
774 config HPET_TIMER
775 def_bool X86_64
776 prompt "HPET Timer Support" if X86_32
777 ---help---
778 Use the IA-PC HPET (High Precision Event Timer) to manage
779 time in preference to the PIT and RTC, if a HPET is
780 present.
781 HPET is the next generation timer replacing legacy 8254s.
782 The HPET provides a stable time base on SMP
783 systems, unlike the TSC, but it is more expensive to access,
784 as it is off-chip. The interface used is documented
785 in the HPET spec, revision 1.
786
787 You can safely choose Y here. However, HPET will only be
788 activated if the platform and the BIOS support this feature.
789 Otherwise the 8254 will be used for timing services.
790
791 Choose N to continue using the legacy 8254 timer.
792
793 config HPET_EMULATE_RTC
794 def_bool y
795 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
796
797 config APB_TIMER
798 def_bool y if X86_INTEL_MID
799 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
800 select DW_APB_TIMER
801 depends on X86_INTEL_MID && SFI
802 help
803 APB timer is the replacement for 8254, HPET on X86 MID platforms.
804 The APBT provides a stable time base on SMP
805 systems, unlike the TSC, but it is more expensive to access,
806 as it is off-chip. APB timers are always running regardless of CPU
807 C states, they are used as per CPU clockevent device when possible.
808
809 # Mark as expert because too many people got it wrong.
810 # The code disables itself when not needed.
811 config DMI
812 default y
813 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
814 bool "Enable DMI scanning" if EXPERT
815 ---help---
816 Enabled scanning of DMI to identify machine quirks. Say Y
817 here unless you have verified that your setup is not
818 affected by entries in the DMI blacklist. Required by PNP
819 BIOS code.
820
821 config GART_IOMMU
822 bool "Old AMD GART IOMMU support"
823 select SWIOTLB
824 depends on X86_64 && PCI && AMD_NB
825 ---help---
826 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
827 GART based hardware IOMMUs.
828
829 The GART supports full DMA access for devices with 32-bit access
830 limitations, on systems with more than 3 GB. This is usually needed
831 for USB, sound, many IDE/SATA chipsets and some other devices.
832
833 Newer systems typically have a modern AMD IOMMU, supported via
834 the CONFIG_AMD_IOMMU=y config option.
835
836 In normal configurations this driver is only active when needed:
837 there's more than 3 GB of memory and the system contains a
838 32-bit limited device.
839
840 If unsure, say Y.
841
842 config CALGARY_IOMMU
843 bool "IBM Calgary IOMMU support"
844 select SWIOTLB
845 depends on X86_64 && PCI
846 ---help---
847 Support for hardware IOMMUs in IBM's xSeries x366 and x460
848 systems. Needed to run systems with more than 3GB of memory
849 properly with 32-bit PCI devices that do not support DAC
850 (Double Address Cycle). Calgary also supports bus level
851 isolation, where all DMAs pass through the IOMMU. This
852 prevents them from going anywhere except their intended
853 destination. This catches hard-to-find kernel bugs and
854 mis-behaving drivers and devices that do not use the DMA-API
855 properly to set up their DMA buffers. The IOMMU can be
856 turned off at boot time with the iommu=off parameter.
857 Normally the kernel will make the right choice by itself.
858 If unsure, say Y.
859
860 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
861 def_bool y
862 prompt "Should Calgary be enabled by default?"
863 depends on CALGARY_IOMMU
864 ---help---
865 Should Calgary be enabled by default? if you choose 'y', Calgary
866 will be used (if it exists). If you choose 'n', Calgary will not be
867 used even if it exists. If you choose 'n' and would like to use
868 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
869 If unsure, say Y.
870
871 # need this always selected by IOMMU for the VIA workaround
872 config SWIOTLB
873 def_bool y if X86_64
874 ---help---
875 Support for software bounce buffers used on x86-64 systems
876 which don't have a hardware IOMMU. Using this PCI devices
877 which can only access 32-bits of memory can be used on systems
878 with more than 3 GB of memory.
879 If unsure, say Y.
880
881 config IOMMU_HELPER
882 def_bool y
883 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
884
885 config MAXSMP
886 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
887 depends on X86_64 && SMP && DEBUG_KERNEL
888 select CPUMASK_OFFSTACK
889 ---help---
890 Enable maximum number of CPUS and NUMA Nodes for this architecture.
891 If unsure, say N.
892
893 config NR_CPUS
894 int "Maximum number of CPUs" if SMP && !MAXSMP
895 range 2 8 if SMP && X86_32 && !X86_BIGSMP
896 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
897 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
898 default "1" if !SMP
899 default "8192" if MAXSMP
900 default "32" if SMP && X86_BIGSMP
901 default "8" if SMP && X86_32
902 default "64" if SMP
903 ---help---
904 This allows you to specify the maximum number of CPUs which this
905 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
906 supported value is 8192, otherwise the maximum value is 512. The
907 minimum value which makes sense is 2.
908
909 This is purely to save memory - each supported CPU adds
910 approximately eight kilobytes to the kernel image.
911
912 config SCHED_SMT
913 bool "SMT (Hyperthreading) scheduler support"
914 depends on SMP
915 ---help---
916 SMT scheduler support improves the CPU scheduler's decision making
917 when dealing with Intel Pentium 4 chips with HyperThreading at a
918 cost of slightly increased overhead in some places. If unsure say
919 N here.
920
921 config SCHED_MC
922 def_bool y
923 prompt "Multi-core scheduler support"
924 depends on SMP
925 ---help---
926 Multi-core scheduler support improves the CPU scheduler's decision
927 making when dealing with multi-core CPU chips at a cost of slightly
928 increased overhead in some places. If unsure say N here.
929
930 source "kernel/Kconfig.preempt"
931
932 config UP_LATE_INIT
933 def_bool y
934 depends on !SMP && X86_LOCAL_APIC
935
936 config X86_UP_APIC
937 bool "Local APIC support on uniprocessors" if !PCI_MSI
938 default PCI_MSI
939 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
940 ---help---
941 A local APIC (Advanced Programmable Interrupt Controller) is an
942 integrated interrupt controller in the CPU. If you have a single-CPU
943 system which has a processor with a local APIC, you can say Y here to
944 enable and use it. If you say Y here even though your machine doesn't
945 have a local APIC, then the kernel will still run with no slowdown at
946 all. The local APIC supports CPU-generated self-interrupts (timer,
947 performance counters), and the NMI watchdog which detects hard
948 lockups.
949
950 config X86_UP_IOAPIC
951 bool "IO-APIC support on uniprocessors"
952 depends on X86_UP_APIC
953 ---help---
954 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
955 SMP-capable replacement for PC-style interrupt controllers. Most
956 SMP systems and many recent uniprocessor systems have one.
957
958 If you have a single-CPU system with an IO-APIC, you can say Y here
959 to use it. If you say Y here even though your machine doesn't have
960 an IO-APIC, then the kernel will still run with no slowdown at all.
961
962 config X86_LOCAL_APIC
963 def_bool y
964 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
965 select IRQ_DOMAIN_HIERARCHY
966 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
967
968 config X86_IO_APIC
969 def_bool y
970 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
971
972 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
973 bool "Reroute for broken boot IRQs"
974 depends on X86_IO_APIC
975 ---help---
976 This option enables a workaround that fixes a source of
977 spurious interrupts. This is recommended when threaded
978 interrupt handling is used on systems where the generation of
979 superfluous "boot interrupts" cannot be disabled.
980
981 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
982 entry in the chipset's IO-APIC is masked (as, e.g. the RT
983 kernel does during interrupt handling). On chipsets where this
984 boot IRQ generation cannot be disabled, this workaround keeps
985 the original IRQ line masked so that only the equivalent "boot
986 IRQ" is delivered to the CPUs. The workaround also tells the
987 kernel to set up the IRQ handler on the boot IRQ line. In this
988 way only one interrupt is delivered to the kernel. Otherwise
989 the spurious second interrupt may cause the kernel to bring
990 down (vital) interrupt lines.
991
992 Only affects "broken" chipsets. Interrupt sharing may be
993 increased on these systems.
994
995 config X86_MCE
996 bool "Machine Check / overheating reporting"
997 select GENERIC_ALLOCATOR
998 default y
999 ---help---
1000 Machine Check support allows the processor to notify the
1001 kernel if it detects a problem (e.g. overheating, data corruption).
1002 The action the kernel takes depends on the severity of the problem,
1003 ranging from warning messages to halting the machine.
1004
1005 config X86_MCE_INTEL
1006 def_bool y
1007 prompt "Intel MCE features"
1008 depends on X86_MCE && X86_LOCAL_APIC
1009 ---help---
1010 Additional support for intel specific MCE features such as
1011 the thermal monitor.
1012
1013 config X86_MCE_AMD
1014 def_bool y
1015 prompt "AMD MCE features"
1016 depends on X86_MCE && X86_LOCAL_APIC
1017 ---help---
1018 Additional support for AMD specific MCE features such as
1019 the DRAM Error Threshold.
1020
1021 config X86_ANCIENT_MCE
1022 bool "Support for old Pentium 5 / WinChip machine checks"
1023 depends on X86_32 && X86_MCE
1024 ---help---
1025 Include support for machine check handling on old Pentium 5 or WinChip
1026 systems. These typically need to be enabled explicitly on the command
1027 line.
1028
1029 config X86_MCE_THRESHOLD
1030 depends on X86_MCE_AMD || X86_MCE_INTEL
1031 def_bool y
1032
1033 config X86_MCE_INJECT
1034 depends on X86_MCE
1035 tristate "Machine check injector support"
1036 ---help---
1037 Provide support for injecting machine checks for testing purposes.
1038 If you don't know what a machine check is and you don't do kernel
1039 QA it is safe to say n.
1040
1041 config X86_THERMAL_VECTOR
1042 def_bool y
1043 depends on X86_MCE_INTEL
1044
1045 source "arch/x86/events/Kconfig"
1046
1047 config X86_LEGACY_VM86
1048 bool "Legacy VM86 support"
1049 default n
1050 depends on X86_32
1051 ---help---
1052 This option allows user programs to put the CPU into V8086
1053 mode, which is an 80286-era approximation of 16-bit real mode.
1054
1055 Some very old versions of X and/or vbetool require this option
1056 for user mode setting. Similarly, DOSEMU will use it if
1057 available to accelerate real mode DOS programs. However, any
1058 recent version of DOSEMU, X, or vbetool should be fully
1059 functional even without kernel VM86 support, as they will all
1060 fall back to software emulation. Nevertheless, if you are using
1061 a 16-bit DOS program where 16-bit performance matters, vm86
1062 mode might be faster than emulation and you might want to
1063 enable this option.
1064
1065 Note that any app that works on a 64-bit kernel is unlikely to
1066 need this option, as 64-bit kernels don't, and can't, support
1067 V8086 mode. This option is also unrelated to 16-bit protected
1068 mode and is not needed to run most 16-bit programs under Wine.
1069
1070 Enabling this option increases the complexity of the kernel
1071 and slows down exception handling a tiny bit.
1072
1073 If unsure, say N here.
1074
1075 config VM86
1076 bool
1077 default X86_LEGACY_VM86
1078
1079 config X86_16BIT
1080 bool "Enable support for 16-bit segments" if EXPERT
1081 default y
1082 depends on MODIFY_LDT_SYSCALL
1083 ---help---
1084 This option is required by programs like Wine to run 16-bit
1085 protected mode legacy code on x86 processors. Disabling
1086 this option saves about 300 bytes on i386, or around 6K text
1087 plus 16K runtime memory on x86-64,
1088
1089 config X86_ESPFIX32
1090 def_bool y
1091 depends on X86_16BIT && X86_32
1092
1093 config X86_ESPFIX64
1094 def_bool y
1095 depends on X86_16BIT && X86_64
1096
1097 config X86_VSYSCALL_EMULATION
1098 bool "Enable vsyscall emulation" if EXPERT
1099 default y
1100 depends on X86_64
1101 ---help---
1102 This enables emulation of the legacy vsyscall page. Disabling
1103 it is roughly equivalent to booting with vsyscall=none, except
1104 that it will also disable the helpful warning if a program
1105 tries to use a vsyscall. With this option set to N, offending
1106 programs will just segfault, citing addresses of the form
1107 0xffffffffff600?00.
1108
1109 This option is required by many programs built before 2013, and
1110 care should be used even with newer programs if set to N.
1111
1112 Disabling this option saves about 7K of kernel size and
1113 possibly 4K of additional runtime pagetable memory.
1114
1115 config TOSHIBA
1116 tristate "Toshiba Laptop support"
1117 depends on X86_32
1118 ---help---
1119 This adds a driver to safely access the System Management Mode of
1120 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1121 not work on models with a Phoenix BIOS. The System Management Mode
1122 is used to set the BIOS and power saving options on Toshiba portables.
1123
1124 For information on utilities to make use of this driver see the
1125 Toshiba Linux utilities web site at:
1126 <http://www.buzzard.org.uk/toshiba/>.
1127
1128 Say Y if you intend to run this kernel on a Toshiba portable.
1129 Say N otherwise.
1130
1131 config I8K
1132 tristate "Dell i8k legacy laptop support"
1133 select HWMON
1134 select SENSORS_DELL_SMM
1135 ---help---
1136 This option enables legacy /proc/i8k userspace interface in hwmon
1137 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1138 temperature and allows controlling fan speeds of Dell laptops via
1139 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1140 it reports also power and hotkey status. For fan speed control is
1141 needed userspace package i8kutils.
1142
1143 Say Y if you intend to run this kernel on old Dell laptops or want to
1144 use userspace package i8kutils.
1145 Say N otherwise.
1146
1147 config X86_REBOOTFIXUPS
1148 bool "Enable X86 board specific fixups for reboot"
1149 depends on X86_32
1150 ---help---
1151 This enables chipset and/or board specific fixups to be done
1152 in order to get reboot to work correctly. This is only needed on
1153 some combinations of hardware and BIOS. The symptom, for which
1154 this config is intended, is when reboot ends with a stalled/hung
1155 system.
1156
1157 Currently, the only fixup is for the Geode machines using
1158 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1159
1160 Say Y if you want to enable the fixup. Currently, it's safe to
1161 enable this option even if you don't need it.
1162 Say N otherwise.
1163
1164 config MICROCODE
1165 bool "CPU microcode loading support"
1166 default y
1167 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1168 select FW_LOADER
1169 ---help---
1170 If you say Y here, you will be able to update the microcode on
1171 Intel and AMD processors. The Intel support is for the IA32 family,
1172 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1173 AMD support is for families 0x10 and later. You will obviously need
1174 the actual microcode binary data itself which is not shipped with
1175 the Linux kernel.
1176
1177 The preferred method to load microcode from a detached initrd is described
1178 in Documentation/x86/early-microcode.txt. For that you need to enable
1179 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1180 initrd for microcode blobs.
1181
1182 In addition, you can build-in the microcode into the kernel. For that you
1183 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1184 to the CONFIG_EXTRA_FIRMWARE config option.
1185
1186 config MICROCODE_INTEL
1187 bool "Intel microcode loading support"
1188 depends on MICROCODE
1189 default MICROCODE
1190 select FW_LOADER
1191 ---help---
1192 This options enables microcode patch loading support for Intel
1193 processors.
1194
1195 For the current Intel microcode data package go to
1196 <https://downloadcenter.intel.com> and search for
1197 'Linux Processor Microcode Data File'.
1198
1199 config MICROCODE_AMD
1200 bool "AMD microcode loading support"
1201 depends on MICROCODE
1202 select FW_LOADER
1203 ---help---
1204 If you select this option, microcode patch loading support for AMD
1205 processors will be enabled.
1206
1207 config MICROCODE_OLD_INTERFACE
1208 def_bool y
1209 depends on MICROCODE
1210
1211 config X86_MSR
1212 tristate "/dev/cpu/*/msr - Model-specific register support"
1213 ---help---
1214 This device gives privileged processes access to the x86
1215 Model-Specific Registers (MSRs). It is a character device with
1216 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1217 MSR accesses are directed to a specific CPU on multi-processor
1218 systems.
1219
1220 config X86_CPUID
1221 tristate "/dev/cpu/*/cpuid - CPU information support"
1222 ---help---
1223 This device gives processes access to the x86 CPUID instruction to
1224 be executed on a specific processor. It is a character device
1225 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1226 /dev/cpu/31/cpuid.
1227
1228 choice
1229 prompt "High Memory Support"
1230 default HIGHMEM4G
1231 depends on X86_32
1232
1233 config NOHIGHMEM
1234 bool "off"
1235 ---help---
1236 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1237 However, the address space of 32-bit x86 processors is only 4
1238 Gigabytes large. That means that, if you have a large amount of
1239 physical memory, not all of it can be "permanently mapped" by the
1240 kernel. The physical memory that's not permanently mapped is called
1241 "high memory".
1242
1243 If you are compiling a kernel which will never run on a machine with
1244 more than 1 Gigabyte total physical RAM, answer "off" here (default
1245 choice and suitable for most users). This will result in a "3GB/1GB"
1246 split: 3GB are mapped so that each process sees a 3GB virtual memory
1247 space and the remaining part of the 4GB virtual memory space is used
1248 by the kernel to permanently map as much physical memory as
1249 possible.
1250
1251 If the machine has between 1 and 4 Gigabytes physical RAM, then
1252 answer "4GB" here.
1253
1254 If more than 4 Gigabytes is used then answer "64GB" here. This
1255 selection turns Intel PAE (Physical Address Extension) mode on.
1256 PAE implements 3-level paging on IA32 processors. PAE is fully
1257 supported by Linux, PAE mode is implemented on all recent Intel
1258 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1259 then the kernel will not boot on CPUs that don't support PAE!
1260
1261 The actual amount of total physical memory will either be
1262 auto detected or can be forced by using a kernel command line option
1263 such as "mem=256M". (Try "man bootparam" or see the documentation of
1264 your boot loader (lilo or loadlin) about how to pass options to the
1265 kernel at boot time.)
1266
1267 If unsure, say "off".
1268
1269 config HIGHMEM4G
1270 bool "4GB"
1271 ---help---
1272 Select this if you have a 32-bit processor and between 1 and 4
1273 gigabytes of physical RAM.
1274
1275 config HIGHMEM64G
1276 bool "64GB"
1277 depends on !M486
1278 select X86_PAE
1279 ---help---
1280 Select this if you have a 32-bit processor and more than 4
1281 gigabytes of physical RAM.
1282
1283 endchoice
1284
1285 choice
1286 prompt "Memory split" if EXPERT
1287 default VMSPLIT_3G
1288 depends on X86_32
1289 ---help---
1290 Select the desired split between kernel and user memory.
1291
1292 If the address range available to the kernel is less than the
1293 physical memory installed, the remaining memory will be available
1294 as "high memory". Accessing high memory is a little more costly
1295 than low memory, as it needs to be mapped into the kernel first.
1296 Note that increasing the kernel address space limits the range
1297 available to user programs, making the address space there
1298 tighter. Selecting anything other than the default 3G/1G split
1299 will also likely make your kernel incompatible with binary-only
1300 kernel modules.
1301
1302 If you are not absolutely sure what you are doing, leave this
1303 option alone!
1304
1305 config VMSPLIT_3G
1306 bool "3G/1G user/kernel split"
1307 config VMSPLIT_3G_OPT
1308 depends on !X86_PAE
1309 bool "3G/1G user/kernel split (for full 1G low memory)"
1310 config VMSPLIT_2G
1311 bool "2G/2G user/kernel split"
1312 config VMSPLIT_2G_OPT
1313 depends on !X86_PAE
1314 bool "2G/2G user/kernel split (for full 2G low memory)"
1315 config VMSPLIT_1G
1316 bool "1G/3G user/kernel split"
1317 endchoice
1318
1319 config PAGE_OFFSET
1320 hex
1321 default 0xB0000000 if VMSPLIT_3G_OPT
1322 default 0x80000000 if VMSPLIT_2G
1323 default 0x78000000 if VMSPLIT_2G_OPT
1324 default 0x40000000 if VMSPLIT_1G
1325 default 0xC0000000
1326 depends on X86_32
1327
1328 config HIGHMEM
1329 def_bool y
1330 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1331
1332 config X86_PAE
1333 bool "PAE (Physical Address Extension) Support"
1334 depends on X86_32 && !HIGHMEM4G
1335 select SWIOTLB
1336 ---help---
1337 PAE is required for NX support, and furthermore enables
1338 larger swapspace support for non-overcommit purposes. It
1339 has the cost of more pagetable lookup overhead, and also
1340 consumes more pagetable space per process.
1341
1342 config ARCH_PHYS_ADDR_T_64BIT
1343 def_bool y
1344 depends on X86_64 || X86_PAE
1345
1346 config ARCH_DMA_ADDR_T_64BIT
1347 def_bool y
1348 depends on X86_64 || HIGHMEM64G
1349
1350 config X86_DIRECT_GBPAGES
1351 def_bool y
1352 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1353 ---help---
1354 Certain kernel features effectively disable kernel
1355 linear 1 GB mappings (even if the CPU otherwise
1356 supports them), so don't confuse the user by printing
1357 that we have them enabled.
1358
1359 # Common NUMA Features
1360 config NUMA
1361 bool "Numa Memory Allocation and Scheduler Support"
1362 depends on SMP
1363 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1364 default y if X86_BIGSMP
1365 ---help---
1366 Enable NUMA (Non Uniform Memory Access) support.
1367
1368 The kernel will try to allocate memory used by a CPU on the
1369 local memory controller of the CPU and add some more
1370 NUMA awareness to the kernel.
1371
1372 For 64-bit this is recommended if the system is Intel Core i7
1373 (or later), AMD Opteron, or EM64T NUMA.
1374
1375 For 32-bit this is only needed if you boot a 32-bit
1376 kernel on a 64-bit NUMA platform.
1377
1378 Otherwise, you should say N.
1379
1380 config AMD_NUMA
1381 def_bool y
1382 prompt "Old style AMD Opteron NUMA detection"
1383 depends on X86_64 && NUMA && PCI
1384 ---help---
1385 Enable AMD NUMA node topology detection. You should say Y here if
1386 you have a multi processor AMD system. This uses an old method to
1387 read the NUMA configuration directly from the builtin Northbridge
1388 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1389 which also takes priority if both are compiled in.
1390
1391 config X86_64_ACPI_NUMA
1392 def_bool y
1393 prompt "ACPI NUMA detection"
1394 depends on X86_64 && NUMA && ACPI && PCI
1395 select ACPI_NUMA
1396 ---help---
1397 Enable ACPI SRAT based node topology detection.
1398
1399 # Some NUMA nodes have memory ranges that span
1400 # other nodes. Even though a pfn is valid and
1401 # between a node's start and end pfns, it may not
1402 # reside on that node. See memmap_init_zone()
1403 # for details.
1404 config NODES_SPAN_OTHER_NODES
1405 def_bool y
1406 depends on X86_64_ACPI_NUMA
1407
1408 config NUMA_EMU
1409 bool "NUMA emulation"
1410 depends on NUMA
1411 ---help---
1412 Enable NUMA emulation. A flat machine will be split
1413 into virtual nodes when booted with "numa=fake=N", where N is the
1414 number of nodes. This is only useful for debugging.
1415
1416 config NODES_SHIFT
1417 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1418 range 1 10
1419 default "10" if MAXSMP
1420 default "6" if X86_64
1421 default "3"
1422 depends on NEED_MULTIPLE_NODES
1423 ---help---
1424 Specify the maximum number of NUMA Nodes available on the target
1425 system. Increases memory reserved to accommodate various tables.
1426
1427 config ARCH_HAVE_MEMORY_PRESENT
1428 def_bool y
1429 depends on X86_32 && DISCONTIGMEM
1430
1431 config NEED_NODE_MEMMAP_SIZE
1432 def_bool y
1433 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1434
1435 config ARCH_FLATMEM_ENABLE
1436 def_bool y
1437 depends on X86_32 && !NUMA
1438
1439 config ARCH_DISCONTIGMEM_ENABLE
1440 def_bool y
1441 depends on NUMA && X86_32
1442
1443 config ARCH_DISCONTIGMEM_DEFAULT
1444 def_bool y
1445 depends on NUMA && X86_32
1446
1447 config ARCH_SPARSEMEM_ENABLE
1448 def_bool y
1449 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1450 select SPARSEMEM_STATIC if X86_32
1451 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1452
1453 config ARCH_SPARSEMEM_DEFAULT
1454 def_bool y
1455 depends on X86_64
1456
1457 config ARCH_SELECT_MEMORY_MODEL
1458 def_bool y
1459 depends on ARCH_SPARSEMEM_ENABLE
1460
1461 config ARCH_MEMORY_PROBE
1462 bool "Enable sysfs memory/probe interface"
1463 depends on X86_64 && MEMORY_HOTPLUG
1464 help
1465 This option enables a sysfs memory/probe interface for testing.
1466 See Documentation/memory-hotplug.txt for more information.
1467 If you are unsure how to answer this question, answer N.
1468
1469 config ARCH_PROC_KCORE_TEXT
1470 def_bool y
1471 depends on X86_64 && PROC_KCORE
1472
1473 config ILLEGAL_POINTER_VALUE
1474 hex
1475 default 0 if X86_32
1476 default 0xdead000000000000 if X86_64
1477
1478 source "mm/Kconfig"
1479
1480 config X86_PMEM_LEGACY_DEVICE
1481 bool
1482
1483 config X86_PMEM_LEGACY
1484 tristate "Support non-standard NVDIMMs and ADR protected memory"
1485 depends on PHYS_ADDR_T_64BIT
1486 depends on BLK_DEV
1487 select X86_PMEM_LEGACY_DEVICE
1488 select LIBNVDIMM
1489 help
1490 Treat memory marked using the non-standard e820 type of 12 as used
1491 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1492 The kernel will offer these regions to the 'pmem' driver so
1493 they can be used for persistent storage.
1494
1495 Say Y if unsure.
1496
1497 config HIGHPTE
1498 bool "Allocate 3rd-level pagetables from highmem"
1499 depends on HIGHMEM
1500 ---help---
1501 The VM uses one page table entry for each page of physical memory.
1502 For systems with a lot of RAM, this can be wasteful of precious
1503 low memory. Setting this option will put user-space page table
1504 entries in high memory.
1505
1506 config X86_CHECK_BIOS_CORRUPTION
1507 bool "Check for low memory corruption"
1508 ---help---
1509 Periodically check for memory corruption in low memory, which
1510 is suspected to be caused by BIOS. Even when enabled in the
1511 configuration, it is disabled at runtime. Enable it by
1512 setting "memory_corruption_check=1" on the kernel command
1513 line. By default it scans the low 64k of memory every 60
1514 seconds; see the memory_corruption_check_size and
1515 memory_corruption_check_period parameters in
1516 Documentation/kernel-parameters.txt to adjust this.
1517
1518 When enabled with the default parameters, this option has
1519 almost no overhead, as it reserves a relatively small amount
1520 of memory and scans it infrequently. It both detects corruption
1521 and prevents it from affecting the running system.
1522
1523 It is, however, intended as a diagnostic tool; if repeatable
1524 BIOS-originated corruption always affects the same memory,
1525 you can use memmap= to prevent the kernel from using that
1526 memory.
1527
1528 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1529 bool "Set the default setting of memory_corruption_check"
1530 depends on X86_CHECK_BIOS_CORRUPTION
1531 default y
1532 ---help---
1533 Set whether the default state of memory_corruption_check is
1534 on or off.
1535
1536 config X86_RESERVE_LOW
1537 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1538 default 64
1539 range 4 640
1540 ---help---
1541 Specify the amount of low memory to reserve for the BIOS.
1542
1543 The first page contains BIOS data structures that the kernel
1544 must not use, so that page must always be reserved.
1545
1546 By default we reserve the first 64K of physical RAM, as a
1547 number of BIOSes are known to corrupt that memory range
1548 during events such as suspend/resume or monitor cable
1549 insertion, so it must not be used by the kernel.
1550
1551 You can set this to 4 if you are absolutely sure that you
1552 trust the BIOS to get all its memory reservations and usages
1553 right. If you know your BIOS have problems beyond the
1554 default 64K area, you can set this to 640 to avoid using the
1555 entire low memory range.
1556
1557 If you have doubts about the BIOS (e.g. suspend/resume does
1558 not work or there's kernel crashes after certain hardware
1559 hotplug events) then you might want to enable
1560 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1561 typical corruption patterns.
1562
1563 Leave this to the default value of 64 if you are unsure.
1564
1565 config MATH_EMULATION
1566 bool
1567 depends on MODIFY_LDT_SYSCALL
1568 prompt "Math emulation" if X86_32
1569 ---help---
1570 Linux can emulate a math coprocessor (used for floating point
1571 operations) if you don't have one. 486DX and Pentium processors have
1572 a math coprocessor built in, 486SX and 386 do not, unless you added
1573 a 487DX or 387, respectively. (The messages during boot time can
1574 give you some hints here ["man dmesg"].) Everyone needs either a
1575 coprocessor or this emulation.
1576
1577 If you don't have a math coprocessor, you need to say Y here; if you
1578 say Y here even though you have a coprocessor, the coprocessor will
1579 be used nevertheless. (This behavior can be changed with the kernel
1580 command line option "no387", which comes handy if your coprocessor
1581 is broken. Try "man bootparam" or see the documentation of your boot
1582 loader (lilo or loadlin) about how to pass options to the kernel at
1583 boot time.) This means that it is a good idea to say Y here if you
1584 intend to use this kernel on different machines.
1585
1586 More information about the internals of the Linux math coprocessor
1587 emulation can be found in <file:arch/x86/math-emu/README>.
1588
1589 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1590 kernel, it won't hurt.
1591
1592 config MTRR
1593 def_bool y
1594 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1595 ---help---
1596 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1597 the Memory Type Range Registers (MTRRs) may be used to control
1598 processor access to memory ranges. This is most useful if you have
1599 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1600 allows bus write transfers to be combined into a larger transfer
1601 before bursting over the PCI/AGP bus. This can increase performance
1602 of image write operations 2.5 times or more. Saying Y here creates a
1603 /proc/mtrr file which may be used to manipulate your processor's
1604 MTRRs. Typically the X server should use this.
1605
1606 This code has a reasonably generic interface so that similar
1607 control registers on other processors can be easily supported
1608 as well:
1609
1610 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1611 Registers (ARRs) which provide a similar functionality to MTRRs. For
1612 these, the ARRs are used to emulate the MTRRs.
1613 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1614 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1615 write-combining. All of these processors are supported by this code
1616 and it makes sense to say Y here if you have one of them.
1617
1618 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1619 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1620 can lead to all sorts of problems, so it's good to say Y here.
1621
1622 You can safely say Y even if your machine doesn't have MTRRs, you'll
1623 just add about 9 KB to your kernel.
1624
1625 See <file:Documentation/x86/mtrr.txt> for more information.
1626
1627 config MTRR_SANITIZER
1628 def_bool y
1629 prompt "MTRR cleanup support"
1630 depends on MTRR
1631 ---help---
1632 Convert MTRR layout from continuous to discrete, so X drivers can
1633 add writeback entries.
1634
1635 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1636 The largest mtrr entry size for a continuous block can be set with
1637 mtrr_chunk_size.
1638
1639 If unsure, say Y.
1640
1641 config MTRR_SANITIZER_ENABLE_DEFAULT
1642 int "MTRR cleanup enable value (0-1)"
1643 range 0 1
1644 default "0"
1645 depends on MTRR_SANITIZER
1646 ---help---
1647 Enable mtrr cleanup default value
1648
1649 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1650 int "MTRR cleanup spare reg num (0-7)"
1651 range 0 7
1652 default "1"
1653 depends on MTRR_SANITIZER
1654 ---help---
1655 mtrr cleanup spare entries default, it can be changed via
1656 mtrr_spare_reg_nr=N on the kernel command line.
1657
1658 config X86_PAT
1659 def_bool y
1660 prompt "x86 PAT support" if EXPERT
1661 depends on MTRR
1662 ---help---
1663 Use PAT attributes to setup page level cache control.
1664
1665 PATs are the modern equivalents of MTRRs and are much more
1666 flexible than MTRRs.
1667
1668 Say N here if you see bootup problems (boot crash, boot hang,
1669 spontaneous reboots) or a non-working video driver.
1670
1671 If unsure, say Y.
1672
1673 config ARCH_USES_PG_UNCACHED
1674 def_bool y
1675 depends on X86_PAT
1676
1677 config ARCH_RANDOM
1678 def_bool y
1679 prompt "x86 architectural random number generator" if EXPERT
1680 ---help---
1681 Enable the x86 architectural RDRAND instruction
1682 (Intel Bull Mountain technology) to generate random numbers.
1683 If supported, this is a high bandwidth, cryptographically
1684 secure hardware random number generator.
1685
1686 config X86_SMAP
1687 def_bool y
1688 prompt "Supervisor Mode Access Prevention" if EXPERT
1689 ---help---
1690 Supervisor Mode Access Prevention (SMAP) is a security
1691 feature in newer Intel processors. There is a small
1692 performance cost if this enabled and turned on; there is
1693 also a small increase in the kernel size if this is enabled.
1694
1695 If unsure, say Y.
1696
1697 config X86_INTEL_MPX
1698 prompt "Intel MPX (Memory Protection Extensions)"
1699 def_bool n
1700 depends on CPU_SUP_INTEL
1701 ---help---
1702 MPX provides hardware features that can be used in
1703 conjunction with compiler-instrumented code to check
1704 memory references. It is designed to detect buffer
1705 overflow or underflow bugs.
1706
1707 This option enables running applications which are
1708 instrumented or otherwise use MPX. It does not use MPX
1709 itself inside the kernel or to protect the kernel
1710 against bad memory references.
1711
1712 Enabling this option will make the kernel larger:
1713 ~8k of kernel text and 36 bytes of data on a 64-bit
1714 defconfig. It adds a long to the 'mm_struct' which
1715 will increase the kernel memory overhead of each
1716 process and adds some branches to paths used during
1717 exec() and munmap().
1718
1719 For details, see Documentation/x86/intel_mpx.txt
1720
1721 If unsure, say N.
1722
1723 config X86_INTEL_MEMORY_PROTECTION_KEYS
1724 prompt "Intel Memory Protection Keys"
1725 def_bool y
1726 # Note: only available in 64-bit mode
1727 depends on CPU_SUP_INTEL && X86_64
1728 ---help---
1729 Memory Protection Keys provides a mechanism for enforcing
1730 page-based protections, but without requiring modification of the
1731 page tables when an application changes protection domains.
1732
1733 For details, see Documentation/x86/protection-keys.txt
1734
1735 If unsure, say y.
1736
1737 config EFI
1738 bool "EFI runtime service support"
1739 depends on ACPI
1740 select UCS2_STRING
1741 select EFI_RUNTIME_WRAPPERS
1742 ---help---
1743 This enables the kernel to use EFI runtime services that are
1744 available (such as the EFI variable services).
1745
1746 This option is only useful on systems that have EFI firmware.
1747 In addition, you should use the latest ELILO loader available
1748 at <http://elilo.sourceforge.net> in order to take advantage
1749 of EFI runtime services. However, even with this option, the
1750 resultant kernel should continue to boot on existing non-EFI
1751 platforms.
1752
1753 config EFI_STUB
1754 bool "EFI stub support"
1755 depends on EFI && !X86_USE_3DNOW
1756 select RELOCATABLE
1757 ---help---
1758 This kernel feature allows a bzImage to be loaded directly
1759 by EFI firmware without the use of a bootloader.
1760
1761 See Documentation/efi-stub.txt for more information.
1762
1763 config EFI_MIXED
1764 bool "EFI mixed-mode support"
1765 depends on EFI_STUB && X86_64
1766 ---help---
1767 Enabling this feature allows a 64-bit kernel to be booted
1768 on a 32-bit firmware, provided that your CPU supports 64-bit
1769 mode.
1770
1771 Note that it is not possible to boot a mixed-mode enabled
1772 kernel via the EFI boot stub - a bootloader that supports
1773 the EFI handover protocol must be used.
1774
1775 If unsure, say N.
1776
1777 config SECCOMP
1778 def_bool y
1779 prompt "Enable seccomp to safely compute untrusted bytecode"
1780 ---help---
1781 This kernel feature is useful for number crunching applications
1782 that may need to compute untrusted bytecode during their
1783 execution. By using pipes or other transports made available to
1784 the process as file descriptors supporting the read/write
1785 syscalls, it's possible to isolate those applications in
1786 their own address space using seccomp. Once seccomp is
1787 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1788 and the task is only allowed to execute a few safe syscalls
1789 defined by each seccomp mode.
1790
1791 If unsure, say Y. Only embedded should say N here.
1792
1793 source kernel/Kconfig.hz
1794
1795 config KEXEC
1796 bool "kexec system call"
1797 select KEXEC_CORE
1798 ---help---
1799 kexec is a system call that implements the ability to shutdown your
1800 current kernel, and to start another kernel. It is like a reboot
1801 but it is independent of the system firmware. And like a reboot
1802 you can start any kernel with it, not just Linux.
1803
1804 The name comes from the similarity to the exec system call.
1805
1806 It is an ongoing process to be certain the hardware in a machine
1807 is properly shutdown, so do not be surprised if this code does not
1808 initially work for you. As of this writing the exact hardware
1809 interface is strongly in flux, so no good recommendation can be
1810 made.
1811
1812 config KEXEC_FILE
1813 bool "kexec file based system call"
1814 select KEXEC_CORE
1815 select BUILD_BIN2C
1816 depends on X86_64
1817 depends on CRYPTO=y
1818 depends on CRYPTO_SHA256=y
1819 ---help---
1820 This is new version of kexec system call. This system call is
1821 file based and takes file descriptors as system call argument
1822 for kernel and initramfs as opposed to list of segments as
1823 accepted by previous system call.
1824
1825 config KEXEC_VERIFY_SIG
1826 bool "Verify kernel signature during kexec_file_load() syscall"
1827 depends on KEXEC_FILE
1828 ---help---
1829 This option makes kernel signature verification mandatory for
1830 the kexec_file_load() syscall.
1831
1832 In addition to that option, you need to enable signature
1833 verification for the corresponding kernel image type being
1834 loaded in order for this to work.
1835
1836 config KEXEC_BZIMAGE_VERIFY_SIG
1837 bool "Enable bzImage signature verification support"
1838 depends on KEXEC_VERIFY_SIG
1839 depends on SIGNED_PE_FILE_VERIFICATION
1840 select SYSTEM_TRUSTED_KEYRING
1841 ---help---
1842 Enable bzImage signature verification support.
1843
1844 config CRASH_DUMP
1845 bool "kernel crash dumps"
1846 depends on X86_64 || (X86_32 && HIGHMEM)
1847 ---help---
1848 Generate crash dump after being started by kexec.
1849 This should be normally only set in special crash dump kernels
1850 which are loaded in the main kernel with kexec-tools into
1851 a specially reserved region and then later executed after
1852 a crash by kdump/kexec. The crash dump kernel must be compiled
1853 to a memory address not used by the main kernel or BIOS using
1854 PHYSICAL_START, or it must be built as a relocatable image
1855 (CONFIG_RELOCATABLE=y).
1856 For more details see Documentation/kdump/kdump.txt
1857
1858 config KEXEC_JUMP
1859 bool "kexec jump"
1860 depends on KEXEC && HIBERNATION
1861 ---help---
1862 Jump between original kernel and kexeced kernel and invoke
1863 code in physical address mode via KEXEC
1864
1865 config PHYSICAL_START
1866 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1867 default "0x1000000"
1868 ---help---
1869 This gives the physical address where the kernel is loaded.
1870
1871 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1872 bzImage will decompress itself to above physical address and
1873 run from there. Otherwise, bzImage will run from the address where
1874 it has been loaded by the boot loader and will ignore above physical
1875 address.
1876
1877 In normal kdump cases one does not have to set/change this option
1878 as now bzImage can be compiled as a completely relocatable image
1879 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1880 address. This option is mainly useful for the folks who don't want
1881 to use a bzImage for capturing the crash dump and want to use a
1882 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1883 to be specifically compiled to run from a specific memory area
1884 (normally a reserved region) and this option comes handy.
1885
1886 So if you are using bzImage for capturing the crash dump,
1887 leave the value here unchanged to 0x1000000 and set
1888 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1889 for capturing the crash dump change this value to start of
1890 the reserved region. In other words, it can be set based on
1891 the "X" value as specified in the "crashkernel=YM@XM"
1892 command line boot parameter passed to the panic-ed
1893 kernel. Please take a look at Documentation/kdump/kdump.txt
1894 for more details about crash dumps.
1895
1896 Usage of bzImage for capturing the crash dump is recommended as
1897 one does not have to build two kernels. Same kernel can be used
1898 as production kernel and capture kernel. Above option should have
1899 gone away after relocatable bzImage support is introduced. But it
1900 is present because there are users out there who continue to use
1901 vmlinux for dump capture. This option should go away down the
1902 line.
1903
1904 Don't change this unless you know what you are doing.
1905
1906 config RELOCATABLE
1907 bool "Build a relocatable kernel"
1908 default y
1909 ---help---
1910 This builds a kernel image that retains relocation information
1911 so it can be loaded someplace besides the default 1MB.
1912 The relocations tend to make the kernel binary about 10% larger,
1913 but are discarded at runtime.
1914
1915 One use is for the kexec on panic case where the recovery kernel
1916 must live at a different physical address than the primary
1917 kernel.
1918
1919 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1920 it has been loaded at and the compile time physical address
1921 (CONFIG_PHYSICAL_START) is used as the minimum location.
1922
1923 config RANDOMIZE_BASE
1924 bool "Randomize the address of the kernel image (KASLR)"
1925 depends on RELOCATABLE
1926 default n
1927 ---help---
1928 In support of Kernel Address Space Layout Randomization (KASLR),
1929 this randomizes the physical address at which the kernel image
1930 is decompressed and the virtual address where the kernel
1931 image is mapped, as a security feature that deters exploit
1932 attempts relying on knowledge of the location of kernel
1933 code internals.
1934
1935 On 64-bit, the kernel physical and virtual addresses are
1936 randomized separately. The physical address will be anywhere
1937 between 16MB and the top of physical memory (up to 64TB). The
1938 virtual address will be randomized from 16MB up to 1GB (9 bits
1939 of entropy). Note that this also reduces the memory space
1940 available to kernel modules from 1.5GB to 1GB.
1941
1942 On 32-bit, the kernel physical and virtual addresses are
1943 randomized together. They will be randomized from 16MB up to
1944 512MB (8 bits of entropy).
1945
1946 Entropy is generated using the RDRAND instruction if it is
1947 supported. If RDTSC is supported, its value is mixed into
1948 the entropy pool as well. If neither RDRAND nor RDTSC are
1949 supported, then entropy is read from the i8254 timer. The
1950 usable entropy is limited by the kernel being built using
1951 2GB addressing, and that PHYSICAL_ALIGN must be at a
1952 minimum of 2MB. As a result, only 10 bits of entropy are
1953 theoretically possible, but the implementations are further
1954 limited due to memory layouts.
1955
1956 If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot
1957 time. To enable it, boot with "kaslr" on the kernel command
1958 line (which will also disable hibernation).
1959
1960 If unsure, say N.
1961
1962 # Relocation on x86 needs some additional build support
1963 config X86_NEED_RELOCS
1964 def_bool y
1965 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1966
1967 config PHYSICAL_ALIGN
1968 hex "Alignment value to which kernel should be aligned"
1969 default "0x200000"
1970 range 0x2000 0x1000000 if X86_32
1971 range 0x200000 0x1000000 if X86_64
1972 ---help---
1973 This value puts the alignment restrictions on physical address
1974 where kernel is loaded and run from. Kernel is compiled for an
1975 address which meets above alignment restriction.
1976
1977 If bootloader loads the kernel at a non-aligned address and
1978 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1979 address aligned to above value and run from there.
1980
1981 If bootloader loads the kernel at a non-aligned address and
1982 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1983 load address and decompress itself to the address it has been
1984 compiled for and run from there. The address for which kernel is
1985 compiled already meets above alignment restrictions. Hence the
1986 end result is that kernel runs from a physical address meeting
1987 above alignment restrictions.
1988
1989 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1990 this value must be a multiple of 0x200000.
1991
1992 Don't change this unless you know what you are doing.
1993
1994 config RANDOMIZE_MEMORY
1995 bool "Randomize the kernel memory sections"
1996 depends on X86_64
1997 depends on RANDOMIZE_BASE
1998 default RANDOMIZE_BASE
1999 ---help---
2000 Randomizes the base virtual address of kernel memory sections
2001 (physical memory mapping, vmalloc & vmemmap). This security feature
2002 makes exploits relying on predictable memory locations less reliable.
2003
2004 The order of allocations remains unchanged. Entropy is generated in
2005 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2006 configuration have in average 30,000 different possible virtual
2007 addresses for each memory section.
2008
2009 If unsure, say N.
2010
2011 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2012 hex "Physical memory mapping padding" if EXPERT
2013 depends on RANDOMIZE_MEMORY
2014 default "0xa" if MEMORY_HOTPLUG
2015 default "0x0"
2016 range 0x1 0x40 if MEMORY_HOTPLUG
2017 range 0x0 0x40
2018 ---help---
2019 Define the padding in terabytes added to the existing physical
2020 memory size during kernel memory randomization. It is useful
2021 for memory hotplug support but reduces the entropy available for
2022 address randomization.
2023
2024 If unsure, leave at the default value.
2025
2026 config HOTPLUG_CPU
2027 bool "Support for hot-pluggable CPUs"
2028 depends on SMP
2029 ---help---
2030 Say Y here to allow turning CPUs off and on. CPUs can be
2031 controlled through /sys/devices/system/cpu.
2032 ( Note: power management support will enable this option
2033 automatically on SMP systems. )
2034 Say N if you want to disable CPU hotplug.
2035
2036 config BOOTPARAM_HOTPLUG_CPU0
2037 bool "Set default setting of cpu0_hotpluggable"
2038 default n
2039 depends on HOTPLUG_CPU
2040 ---help---
2041 Set whether default state of cpu0_hotpluggable is on or off.
2042
2043 Say Y here to enable CPU0 hotplug by default. If this switch
2044 is turned on, there is no need to give cpu0_hotplug kernel
2045 parameter and the CPU0 hotplug feature is enabled by default.
2046
2047 Please note: there are two known CPU0 dependencies if you want
2048 to enable the CPU0 hotplug feature either by this switch or by
2049 cpu0_hotplug kernel parameter.
2050
2051 First, resume from hibernate or suspend always starts from CPU0.
2052 So hibernate and suspend are prevented if CPU0 is offline.
2053
2054 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2055 offline if any interrupt can not migrate out of CPU0. There may
2056 be other CPU0 dependencies.
2057
2058 Please make sure the dependencies are under your control before
2059 you enable this feature.
2060
2061 Say N if you don't want to enable CPU0 hotplug feature by default.
2062 You still can enable the CPU0 hotplug feature at boot by kernel
2063 parameter cpu0_hotplug.
2064
2065 config DEBUG_HOTPLUG_CPU0
2066 def_bool n
2067 prompt "Debug CPU0 hotplug"
2068 depends on HOTPLUG_CPU
2069 ---help---
2070 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2071 soon as possible and boots up userspace with CPU0 offlined. User
2072 can online CPU0 back after boot time.
2073
2074 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2075 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2076 compilation or giving cpu0_hotplug kernel parameter at boot.
2077
2078 If unsure, say N.
2079
2080 config COMPAT_VDSO
2081 def_bool n
2082 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2083 depends on X86_32 || IA32_EMULATION
2084 ---help---
2085 Certain buggy versions of glibc will crash if they are
2086 presented with a 32-bit vDSO that is not mapped at the address
2087 indicated in its segment table.
2088
2089 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2090 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2091 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2092 the only released version with the bug, but OpenSUSE 9
2093 contains a buggy "glibc 2.3.2".
2094
2095 The symptom of the bug is that everything crashes on startup, saying:
2096 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2097
2098 Saying Y here changes the default value of the vdso32 boot
2099 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2100 This works around the glibc bug but hurts performance.
2101
2102 If unsure, say N: if you are compiling your own kernel, you
2103 are unlikely to be using a buggy version of glibc.
2104
2105 choice
2106 prompt "vsyscall table for legacy applications"
2107 depends on X86_64
2108 default LEGACY_VSYSCALL_EMULATE
2109 help
2110 Legacy user code that does not know how to find the vDSO expects
2111 to be able to issue three syscalls by calling fixed addresses in
2112 kernel space. Since this location is not randomized with ASLR,
2113 it can be used to assist security vulnerability exploitation.
2114
2115 This setting can be changed at boot time via the kernel command
2116 line parameter vsyscall=[native|emulate|none].
2117
2118 On a system with recent enough glibc (2.14 or newer) and no
2119 static binaries, you can say None without a performance penalty
2120 to improve security.
2121
2122 If unsure, select "Emulate".
2123
2124 config LEGACY_VSYSCALL_NATIVE
2125 bool "Native"
2126 help
2127 Actual executable code is located in the fixed vsyscall
2128 address mapping, implementing time() efficiently. Since
2129 this makes the mapping executable, it can be used during
2130 security vulnerability exploitation (traditionally as
2131 ROP gadgets). This configuration is not recommended.
2132
2133 config LEGACY_VSYSCALL_EMULATE
2134 bool "Emulate"
2135 help
2136 The kernel traps and emulates calls into the fixed
2137 vsyscall address mapping. This makes the mapping
2138 non-executable, but it still contains known contents,
2139 which could be used in certain rare security vulnerability
2140 exploits. This configuration is recommended when userspace
2141 still uses the vsyscall area.
2142
2143 config LEGACY_VSYSCALL_NONE
2144 bool "None"
2145 help
2146 There will be no vsyscall mapping at all. This will
2147 eliminate any risk of ASLR bypass due to the vsyscall
2148 fixed address mapping. Attempts to use the vsyscalls
2149 will be reported to dmesg, so that either old or
2150 malicious userspace programs can be identified.
2151
2152 endchoice
2153
2154 config CMDLINE_BOOL
2155 bool "Built-in kernel command line"
2156 ---help---
2157 Allow for specifying boot arguments to the kernel at
2158 build time. On some systems (e.g. embedded ones), it is
2159 necessary or convenient to provide some or all of the
2160 kernel boot arguments with the kernel itself (that is,
2161 to not rely on the boot loader to provide them.)
2162
2163 To compile command line arguments into the kernel,
2164 set this option to 'Y', then fill in the
2165 boot arguments in CONFIG_CMDLINE.
2166
2167 Systems with fully functional boot loaders (i.e. non-embedded)
2168 should leave this option set to 'N'.
2169
2170 config CMDLINE
2171 string "Built-in kernel command string"
2172 depends on CMDLINE_BOOL
2173 default ""
2174 ---help---
2175 Enter arguments here that should be compiled into the kernel
2176 image and used at boot time. If the boot loader provides a
2177 command line at boot time, it is appended to this string to
2178 form the full kernel command line, when the system boots.
2179
2180 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2181 change this behavior.
2182
2183 In most cases, the command line (whether built-in or provided
2184 by the boot loader) should specify the device for the root
2185 file system.
2186
2187 config CMDLINE_OVERRIDE
2188 bool "Built-in command line overrides boot loader arguments"
2189 depends on CMDLINE_BOOL
2190 ---help---
2191 Set this option to 'Y' to have the kernel ignore the boot loader
2192 command line, and use ONLY the built-in command line.
2193
2194 This is used to work around broken boot loaders. This should
2195 be set to 'N' under normal conditions.
2196
2197 config MODIFY_LDT_SYSCALL
2198 bool "Enable the LDT (local descriptor table)" if EXPERT
2199 default y
2200 ---help---
2201 Linux can allow user programs to install a per-process x86
2202 Local Descriptor Table (LDT) using the modify_ldt(2) system
2203 call. This is required to run 16-bit or segmented code such as
2204 DOSEMU or some Wine programs. It is also used by some very old
2205 threading libraries.
2206
2207 Enabling this feature adds a small amount of overhead to
2208 context switches and increases the low-level kernel attack
2209 surface. Disabling it removes the modify_ldt(2) system call.
2210
2211 Saying 'N' here may make sense for embedded or server kernels.
2212
2213 source "kernel/livepatch/Kconfig"
2214
2215 endmenu
2216
2217 config ARCH_ENABLE_MEMORY_HOTPLUG
2218 def_bool y
2219 depends on X86_64 || (X86_32 && HIGHMEM)
2220
2221 config ARCH_ENABLE_MEMORY_HOTREMOVE
2222 def_bool y
2223 depends on MEMORY_HOTPLUG
2224
2225 config USE_PERCPU_NUMA_NODE_ID
2226 def_bool y
2227 depends on NUMA
2228
2229 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2230 def_bool y
2231 depends on X86_64 || X86_PAE
2232
2233 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2234 def_bool y
2235 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2236
2237 menu "Power management and ACPI options"
2238
2239 config ARCH_HIBERNATION_HEADER
2240 def_bool y
2241 depends on X86_64 && HIBERNATION
2242
2243 source "kernel/power/Kconfig"
2244
2245 source "drivers/acpi/Kconfig"
2246
2247 source "drivers/sfi/Kconfig"
2248
2249 config X86_APM_BOOT
2250 def_bool y
2251 depends on APM
2252
2253 menuconfig APM
2254 tristate "APM (Advanced Power Management) BIOS support"
2255 depends on X86_32 && PM_SLEEP
2256 ---help---
2257 APM is a BIOS specification for saving power using several different
2258 techniques. This is mostly useful for battery powered laptops with
2259 APM compliant BIOSes. If you say Y here, the system time will be
2260 reset after a RESUME operation, the /proc/apm device will provide
2261 battery status information, and user-space programs will receive
2262 notification of APM "events" (e.g. battery status change).
2263
2264 If you select "Y" here, you can disable actual use of the APM
2265 BIOS by passing the "apm=off" option to the kernel at boot time.
2266
2267 Note that the APM support is almost completely disabled for
2268 machines with more than one CPU.
2269
2270 In order to use APM, you will need supporting software. For location
2271 and more information, read <file:Documentation/power/apm-acpi.txt>
2272 and the Battery Powered Linux mini-HOWTO, available from
2273 <http://www.tldp.org/docs.html#howto>.
2274
2275 This driver does not spin down disk drives (see the hdparm(8)
2276 manpage ("man 8 hdparm") for that), and it doesn't turn off
2277 VESA-compliant "green" monitors.
2278
2279 This driver does not support the TI 4000M TravelMate and the ACER
2280 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2281 desktop machines also don't have compliant BIOSes, and this driver
2282 may cause those machines to panic during the boot phase.
2283
2284 Generally, if you don't have a battery in your machine, there isn't
2285 much point in using this driver and you should say N. If you get
2286 random kernel OOPSes or reboots that don't seem to be related to
2287 anything, try disabling/enabling this option (or disabling/enabling
2288 APM in your BIOS).
2289
2290 Some other things you should try when experiencing seemingly random,
2291 "weird" problems:
2292
2293 1) make sure that you have enough swap space and that it is
2294 enabled.
2295 2) pass the "no-hlt" option to the kernel
2296 3) switch on floating point emulation in the kernel and pass
2297 the "no387" option to the kernel
2298 4) pass the "floppy=nodma" option to the kernel
2299 5) pass the "mem=4M" option to the kernel (thereby disabling
2300 all but the first 4 MB of RAM)
2301 6) make sure that the CPU is not over clocked.
2302 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2303 8) disable the cache from your BIOS settings
2304 9) install a fan for the video card or exchange video RAM
2305 10) install a better fan for the CPU
2306 11) exchange RAM chips
2307 12) exchange the motherboard.
2308
2309 To compile this driver as a module, choose M here: the
2310 module will be called apm.
2311
2312 if APM
2313
2314 config APM_IGNORE_USER_SUSPEND
2315 bool "Ignore USER SUSPEND"
2316 ---help---
2317 This option will ignore USER SUSPEND requests. On machines with a
2318 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2319 series notebooks, it is necessary to say Y because of a BIOS bug.
2320
2321 config APM_DO_ENABLE
2322 bool "Enable PM at boot time"
2323 ---help---
2324 Enable APM features at boot time. From page 36 of the APM BIOS
2325 specification: "When disabled, the APM BIOS does not automatically
2326 power manage devices, enter the Standby State, enter the Suspend
2327 State, or take power saving steps in response to CPU Idle calls."
2328 This driver will make CPU Idle calls when Linux is idle (unless this
2329 feature is turned off -- see "Do CPU IDLE calls", below). This
2330 should always save battery power, but more complicated APM features
2331 will be dependent on your BIOS implementation. You may need to turn
2332 this option off if your computer hangs at boot time when using APM
2333 support, or if it beeps continuously instead of suspending. Turn
2334 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2335 T400CDT. This is off by default since most machines do fine without
2336 this feature.
2337
2338 config APM_CPU_IDLE
2339 depends on CPU_IDLE
2340 bool "Make CPU Idle calls when idle"
2341 ---help---
2342 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2343 On some machines, this can activate improved power savings, such as
2344 a slowed CPU clock rate, when the machine is idle. These idle calls
2345 are made after the idle loop has run for some length of time (e.g.,
2346 333 mS). On some machines, this will cause a hang at boot time or
2347 whenever the CPU becomes idle. (On machines with more than one CPU,
2348 this option does nothing.)
2349
2350 config APM_DISPLAY_BLANK
2351 bool "Enable console blanking using APM"
2352 ---help---
2353 Enable console blanking using the APM. Some laptops can use this to
2354 turn off the LCD backlight when the screen blanker of the Linux
2355 virtual console blanks the screen. Note that this is only used by
2356 the virtual console screen blanker, and won't turn off the backlight
2357 when using the X Window system. This also doesn't have anything to
2358 do with your VESA-compliant power-saving monitor. Further, this
2359 option doesn't work for all laptops -- it might not turn off your
2360 backlight at all, or it might print a lot of errors to the console,
2361 especially if you are using gpm.
2362
2363 config APM_ALLOW_INTS
2364 bool "Allow interrupts during APM BIOS calls"
2365 ---help---
2366 Normally we disable external interrupts while we are making calls to
2367 the APM BIOS as a measure to lessen the effects of a badly behaving
2368 BIOS implementation. The BIOS should reenable interrupts if it
2369 needs to. Unfortunately, some BIOSes do not -- especially those in
2370 many of the newer IBM Thinkpads. If you experience hangs when you
2371 suspend, try setting this to Y. Otherwise, say N.
2372
2373 endif # APM
2374
2375 source "drivers/cpufreq/Kconfig"
2376
2377 source "drivers/cpuidle/Kconfig"
2378
2379 source "drivers/idle/Kconfig"
2380
2381 endmenu
2382
2383
2384 menu "Bus options (PCI etc.)"
2385
2386 config PCI
2387 bool "PCI support"
2388 default y
2389 ---help---
2390 Find out whether you have a PCI motherboard. PCI is the name of a
2391 bus system, i.e. the way the CPU talks to the other stuff inside
2392 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2393 VESA. If you have PCI, say Y, otherwise N.
2394
2395 choice
2396 prompt "PCI access mode"
2397 depends on X86_32 && PCI
2398 default PCI_GOANY
2399 ---help---
2400 On PCI systems, the BIOS can be used to detect the PCI devices and
2401 determine their configuration. However, some old PCI motherboards
2402 have BIOS bugs and may crash if this is done. Also, some embedded
2403 PCI-based systems don't have any BIOS at all. Linux can also try to
2404 detect the PCI hardware directly without using the BIOS.
2405
2406 With this option, you can specify how Linux should detect the
2407 PCI devices. If you choose "BIOS", the BIOS will be used,
2408 if you choose "Direct", the BIOS won't be used, and if you
2409 choose "MMConfig", then PCI Express MMCONFIG will be used.
2410 If you choose "Any", the kernel will try MMCONFIG, then the
2411 direct access method and falls back to the BIOS if that doesn't
2412 work. If unsure, go with the default, which is "Any".
2413
2414 config PCI_GOBIOS
2415 bool "BIOS"
2416
2417 config PCI_GOMMCONFIG
2418 bool "MMConfig"
2419
2420 config PCI_GODIRECT
2421 bool "Direct"
2422
2423 config PCI_GOOLPC
2424 bool "OLPC XO-1"
2425 depends on OLPC
2426
2427 config PCI_GOANY
2428 bool "Any"
2429
2430 endchoice
2431
2432 config PCI_BIOS
2433 def_bool y
2434 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2435
2436 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2437 config PCI_DIRECT
2438 def_bool y
2439 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2440
2441 config PCI_MMCONFIG
2442 def_bool y
2443 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2444
2445 config PCI_OLPC
2446 def_bool y
2447 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2448
2449 config PCI_XEN
2450 def_bool y
2451 depends on PCI && XEN
2452 select SWIOTLB_XEN
2453
2454 config PCI_DOMAINS
2455 def_bool y
2456 depends on PCI
2457
2458 config PCI_MMCONFIG
2459 bool "Support mmconfig PCI config space access"
2460 depends on X86_64 && PCI && ACPI
2461
2462 config PCI_CNB20LE_QUIRK
2463 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2464 depends on PCI
2465 help
2466 Read the PCI windows out of the CNB20LE host bridge. This allows
2467 PCI hotplug to work on systems with the CNB20LE chipset which do
2468 not have ACPI.
2469
2470 There's no public spec for this chipset, and this functionality
2471 is known to be incomplete.
2472
2473 You should say N unless you know you need this.
2474
2475 source "drivers/pci/Kconfig"
2476
2477 config ISA_BUS
2478 bool "ISA-style bus support on modern systems" if EXPERT
2479 select ISA_BUS_API
2480 help
2481 Enables ISA-style drivers on modern systems. This is necessary to
2482 support PC/104 devices on X86_64 platforms.
2483
2484 If unsure, say N.
2485
2486 # x86_64 have no ISA slots, but can have ISA-style DMA.
2487 config ISA_DMA_API
2488 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2489 default y
2490 help
2491 Enables ISA-style DMA support for devices requiring such controllers.
2492 If unsure, say Y.
2493
2494 if X86_32
2495
2496 config ISA
2497 bool "ISA support"
2498 ---help---
2499 Find out whether you have ISA slots on your motherboard. ISA is the
2500 name of a bus system, i.e. the way the CPU talks to the other stuff
2501 inside your box. Other bus systems are PCI, EISA, MicroChannel
2502 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2503 newer boards don't support it. If you have ISA, say Y, otherwise N.
2504
2505 config EISA
2506 bool "EISA support"
2507 depends on ISA
2508 ---help---
2509 The Extended Industry Standard Architecture (EISA) bus was
2510 developed as an open alternative to the IBM MicroChannel bus.
2511
2512 The EISA bus provided some of the features of the IBM MicroChannel
2513 bus while maintaining backward compatibility with cards made for
2514 the older ISA bus. The EISA bus saw limited use between 1988 and
2515 1995 when it was made obsolete by the PCI bus.
2516
2517 Say Y here if you are building a kernel for an EISA-based machine.
2518
2519 Otherwise, say N.
2520
2521 source "drivers/eisa/Kconfig"
2522
2523 config SCx200
2524 tristate "NatSemi SCx200 support"
2525 ---help---
2526 This provides basic support for National Semiconductor's
2527 (now AMD's) Geode processors. The driver probes for the
2528 PCI-IDs of several on-chip devices, so its a good dependency
2529 for other scx200_* drivers.
2530
2531 If compiled as a module, the driver is named scx200.
2532
2533 config SCx200HR_TIMER
2534 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2535 depends on SCx200
2536 default y
2537 ---help---
2538 This driver provides a clocksource built upon the on-chip
2539 27MHz high-resolution timer. Its also a workaround for
2540 NSC Geode SC-1100's buggy TSC, which loses time when the
2541 processor goes idle (as is done by the scheduler). The
2542 other workaround is idle=poll boot option.
2543
2544 config OLPC
2545 bool "One Laptop Per Child support"
2546 depends on !X86_PAE
2547 select GPIOLIB
2548 select OF
2549 select OF_PROMTREE
2550 select IRQ_DOMAIN
2551 ---help---
2552 Add support for detecting the unique features of the OLPC
2553 XO hardware.
2554
2555 config OLPC_XO1_PM
2556 bool "OLPC XO-1 Power Management"
2557 depends on OLPC && MFD_CS5535 && PM_SLEEP
2558 select MFD_CORE
2559 ---help---
2560 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2561
2562 config OLPC_XO1_RTC
2563 bool "OLPC XO-1 Real Time Clock"
2564 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2565 ---help---
2566 Add support for the XO-1 real time clock, which can be used as a
2567 programmable wakeup source.
2568
2569 config OLPC_XO1_SCI
2570 bool "OLPC XO-1 SCI extras"
2571 depends on OLPC && OLPC_XO1_PM
2572 depends on INPUT=y
2573 select POWER_SUPPLY
2574 select GPIO_CS5535
2575 select MFD_CORE
2576 ---help---
2577 Add support for SCI-based features of the OLPC XO-1 laptop:
2578 - EC-driven system wakeups
2579 - Power button
2580 - Ebook switch
2581 - Lid switch
2582 - AC adapter status updates
2583 - Battery status updates
2584
2585 config OLPC_XO15_SCI
2586 bool "OLPC XO-1.5 SCI extras"
2587 depends on OLPC && ACPI
2588 select POWER_SUPPLY
2589 ---help---
2590 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2591 - EC-driven system wakeups
2592 - AC adapter status updates
2593 - Battery status updates
2594
2595 config ALIX
2596 bool "PCEngines ALIX System Support (LED setup)"
2597 select GPIOLIB
2598 ---help---
2599 This option enables system support for the PCEngines ALIX.
2600 At present this just sets up LEDs for GPIO control on
2601 ALIX2/3/6 boards. However, other system specific setup should
2602 get added here.
2603
2604 Note: You must still enable the drivers for GPIO and LED support
2605 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2606
2607 Note: You have to set alix.force=1 for boards with Award BIOS.
2608
2609 config NET5501
2610 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2611 select GPIOLIB
2612 ---help---
2613 This option enables system support for the Soekris Engineering net5501.
2614
2615 config GEOS
2616 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2617 select GPIOLIB
2618 depends on DMI
2619 ---help---
2620 This option enables system support for the Traverse Technologies GEOS.
2621
2622 config TS5500
2623 bool "Technologic Systems TS-5500 platform support"
2624 depends on MELAN
2625 select CHECK_SIGNATURE
2626 select NEW_LEDS
2627 select LEDS_CLASS
2628 ---help---
2629 This option enables system support for the Technologic Systems TS-5500.
2630
2631 endif # X86_32
2632
2633 config AMD_NB
2634 def_bool y
2635 depends on CPU_SUP_AMD && PCI
2636
2637 source "drivers/pcmcia/Kconfig"
2638
2639 config RAPIDIO
2640 tristate "RapidIO support"
2641 depends on PCI
2642 default n
2643 help
2644 If enabled this option will include drivers and the core
2645 infrastructure code to support RapidIO interconnect devices.
2646
2647 source "drivers/rapidio/Kconfig"
2648
2649 config X86_SYSFB
2650 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2651 help
2652 Firmwares often provide initial graphics framebuffers so the BIOS,
2653 bootloader or kernel can show basic video-output during boot for
2654 user-guidance and debugging. Historically, x86 used the VESA BIOS
2655 Extensions and EFI-framebuffers for this, which are mostly limited
2656 to x86.
2657 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2658 framebuffers so the new generic system-framebuffer drivers can be
2659 used on x86. If the framebuffer is not compatible with the generic
2660 modes, it is adverticed as fallback platform framebuffer so legacy
2661 drivers like efifb, vesafb and uvesafb can pick it up.
2662 If this option is not selected, all system framebuffers are always
2663 marked as fallback platform framebuffers as usual.
2664
2665 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2666 not be able to pick up generic system framebuffers if this option
2667 is selected. You are highly encouraged to enable simplefb as
2668 replacement if you select this option. simplefb can correctly deal
2669 with generic system framebuffers. But you should still keep vesafb
2670 and others enabled as fallback if a system framebuffer is
2671 incompatible with simplefb.
2672
2673 If unsure, say Y.
2674
2675 endmenu
2676
2677
2678 menu "Executable file formats / Emulations"
2679
2680 source "fs/Kconfig.binfmt"
2681
2682 config IA32_EMULATION
2683 bool "IA32 Emulation"
2684 depends on X86_64
2685 select BINFMT_ELF
2686 select COMPAT_BINFMT_ELF
2687 select ARCH_WANT_OLD_COMPAT_IPC
2688 ---help---
2689 Include code to run legacy 32-bit programs under a
2690 64-bit kernel. You should likely turn this on, unless you're
2691 100% sure that you don't have any 32-bit programs left.
2692
2693 config IA32_AOUT
2694 tristate "IA32 a.out support"
2695 depends on IA32_EMULATION
2696 ---help---
2697 Support old a.out binaries in the 32bit emulation.
2698
2699 config X86_X32
2700 bool "x32 ABI for 64-bit mode"
2701 depends on X86_64
2702 ---help---
2703 Include code to run binaries for the x32 native 32-bit ABI
2704 for 64-bit processors. An x32 process gets access to the
2705 full 64-bit register file and wide data path while leaving
2706 pointers at 32 bits for smaller memory footprint.
2707
2708 You will need a recent binutils (2.22 or later) with
2709 elf32_x86_64 support enabled to compile a kernel with this
2710 option set.
2711
2712 config COMPAT
2713 def_bool y
2714 depends on IA32_EMULATION || X86_X32
2715
2716 if COMPAT
2717 config COMPAT_FOR_U64_ALIGNMENT
2718 def_bool y
2719
2720 config SYSVIPC_COMPAT
2721 def_bool y
2722 depends on SYSVIPC
2723
2724 config KEYS_COMPAT
2725 def_bool y
2726 depends on KEYS
2727 endif
2728
2729 endmenu
2730
2731
2732 config HAVE_ATOMIC_IOMAP
2733 def_bool y
2734 depends on X86_32
2735
2736 config X86_DEV_DMA_OPS
2737 bool
2738 depends on X86_64 || STA2X11
2739
2740 config X86_DMA_REMAP
2741 bool
2742 depends on STA2X11
2743
2744 config PMC_ATOM
2745 def_bool y
2746 depends on PCI
2747
2748 config VMD
2749 depends on PCI_MSI
2750 tristate "Volume Management Device Driver"
2751 default N
2752 ---help---
2753 Adds support for the Intel Volume Management Device (VMD). VMD is a
2754 secondary PCI host bridge that allows PCI Express root ports,
2755 and devices attached to them, to be removed from the default
2756 PCI domain and placed within the VMD domain. This provides
2757 more bus resources than are otherwise possible with a
2758 single domain. If you know your system provides one of these and
2759 has devices attached to it, say Y; if you are not sure, say N.
2760
2761 source "net/Kconfig"
2762
2763 source "drivers/Kconfig"
2764
2765 source "drivers/firmware/Kconfig"
2766
2767 source "fs/Kconfig"
2768
2769 source "arch/x86/Kconfig.debug"
2770
2771 source "security/Kconfig"
2772
2773 source "crypto/Kconfig"
2774
2775 source "arch/x86/kvm/Kconfig"
2776
2777 source "lib/Kconfig"
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