Merge tag 'clk-for-linus-3.15' of git://git.linaro.org/people/mike.turquette/linux
[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 select CLKSRC_I8253
13 select HAVE_UID16
14
15 config X86_64
16 def_bool y
17 depends on 64BIT
18 select X86_DEV_DMA_OPS
19 select ARCH_USE_CMPXCHG_LOCKREF
20
21 ### Arch settings
22 config X86
23 def_bool y
24 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
25 select ARCH_MIGHT_HAVE_PC_PARPORT
26 select ARCH_MIGHT_HAVE_PC_SERIO
27 select HAVE_AOUT if X86_32
28 select HAVE_UNSTABLE_SCHED_CLOCK
29 select ARCH_SUPPORTS_NUMA_BALANCING
30 select ARCH_SUPPORTS_INT128 if X86_64
31 select ARCH_WANTS_PROT_NUMA_PROT_NONE
32 select HAVE_IDE
33 select HAVE_OPROFILE
34 select HAVE_PCSPKR_PLATFORM
35 select HAVE_PERF_EVENTS
36 select HAVE_IOREMAP_PROT
37 select HAVE_KPROBES
38 select HAVE_MEMBLOCK
39 select HAVE_MEMBLOCK_NODE_MAP
40 select ARCH_DISCARD_MEMBLOCK
41 select ARCH_WANT_OPTIONAL_GPIOLIB
42 select ARCH_WANT_FRAME_POINTERS
43 select HAVE_DMA_ATTRS
44 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
45 select HAVE_KRETPROBES
46 select HAVE_OPTPROBES
47 select HAVE_KPROBES_ON_FTRACE
48 select HAVE_FTRACE_MCOUNT_RECORD
49 select HAVE_FENTRY if X86_64
50 select HAVE_C_RECORDMCOUNT
51 select HAVE_DYNAMIC_FTRACE
52 select HAVE_DYNAMIC_FTRACE_WITH_REGS
53 select HAVE_FUNCTION_TRACER
54 select HAVE_FUNCTION_GRAPH_TRACER
55 select HAVE_FUNCTION_GRAPH_FP_TEST
56 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
57 select HAVE_SYSCALL_TRACEPOINTS
58 select SYSCTL_EXCEPTION_TRACE
59 select HAVE_KVM
60 select HAVE_ARCH_KGDB
61 select HAVE_ARCH_TRACEHOOK
62 select HAVE_GENERIC_DMA_COHERENT if X86_32
63 select HAVE_EFFICIENT_UNALIGNED_ACCESS
64 select USER_STACKTRACE_SUPPORT
65 select HAVE_REGS_AND_STACK_ACCESS_API
66 select HAVE_DMA_API_DEBUG
67 select HAVE_KERNEL_GZIP
68 select HAVE_KERNEL_BZIP2
69 select HAVE_KERNEL_LZMA
70 select HAVE_KERNEL_XZ
71 select HAVE_KERNEL_LZO
72 select HAVE_KERNEL_LZ4
73 select HAVE_HW_BREAKPOINT
74 select HAVE_MIXED_BREAKPOINTS_REGS
75 select PERF_EVENTS
76 select HAVE_PERF_EVENTS_NMI
77 select HAVE_PERF_REGS
78 select HAVE_PERF_USER_STACK_DUMP
79 select HAVE_DEBUG_KMEMLEAK
80 select ANON_INODES
81 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
82 select HAVE_CMPXCHG_LOCAL
83 select HAVE_CMPXCHG_DOUBLE
84 select HAVE_ARCH_KMEMCHECK
85 select HAVE_USER_RETURN_NOTIFIER
86 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
87 select HAVE_ARCH_JUMP_LABEL
88 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
89 select SPARSE_IRQ
90 select GENERIC_FIND_FIRST_BIT
91 select GENERIC_IRQ_PROBE
92 select GENERIC_PENDING_IRQ if SMP
93 select GENERIC_IRQ_SHOW
94 select GENERIC_CLOCKEVENTS_MIN_ADJUST
95 select IRQ_FORCED_THREADING
96 select HAVE_BPF_JIT if X86_64
97 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
98 select CLKEVT_I8253
99 select ARCH_HAVE_NMI_SAFE_CMPXCHG
100 select GENERIC_IOMAP
101 select DCACHE_WORD_ACCESS
102 select GENERIC_SMP_IDLE_THREAD
103 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
104 select HAVE_ARCH_SECCOMP_FILTER
105 select BUILDTIME_EXTABLE_SORT
106 select GENERIC_CMOS_UPDATE
107 select HAVE_ARCH_SOFT_DIRTY
108 select CLOCKSOURCE_WATCHDOG
109 select GENERIC_CLOCKEVENTS
110 select ARCH_CLOCKSOURCE_DATA
111 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
112 select GENERIC_TIME_VSYSCALL
113 select KTIME_SCALAR if X86_32
114 select GENERIC_STRNCPY_FROM_USER
115 select GENERIC_STRNLEN_USER
116 select HAVE_CONTEXT_TRACKING if X86_64
117 select HAVE_IRQ_TIME_ACCOUNTING
118 select VIRT_TO_BUS
119 select MODULES_USE_ELF_REL if X86_32
120 select MODULES_USE_ELF_RELA if X86_64
121 select CLONE_BACKWARDS if X86_32
122 select ARCH_USE_BUILTIN_BSWAP
123 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
124 select OLD_SIGACTION if X86_32
125 select COMPAT_OLD_SIGACTION if IA32_EMULATION
126 select RTC_LIB
127 select HAVE_DEBUG_STACKOVERFLOW
128 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
129 select HAVE_CC_STACKPROTECTOR
130 select GENERIC_CPU_AUTOPROBE
131
132 config INSTRUCTION_DECODER
133 def_bool y
134 depends on KPROBES || PERF_EVENTS || UPROBES
135
136 config OUTPUT_FORMAT
137 string
138 default "elf32-i386" if X86_32
139 default "elf64-x86-64" if X86_64
140
141 config ARCH_DEFCONFIG
142 string
143 default "arch/x86/configs/i386_defconfig" if X86_32
144 default "arch/x86/configs/x86_64_defconfig" if X86_64
145
146 config LOCKDEP_SUPPORT
147 def_bool y
148
149 config STACKTRACE_SUPPORT
150 def_bool y
151
152 config HAVE_LATENCYTOP_SUPPORT
153 def_bool y
154
155 config MMU
156 def_bool y
157
158 config SBUS
159 bool
160
161 config NEED_DMA_MAP_STATE
162 def_bool y
163 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
164
165 config NEED_SG_DMA_LENGTH
166 def_bool y
167
168 config GENERIC_ISA_DMA
169 def_bool y
170 depends on ISA_DMA_API
171
172 config GENERIC_BUG
173 def_bool y
174 depends on BUG
175 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
176
177 config GENERIC_BUG_RELATIVE_POINTERS
178 bool
179
180 config GENERIC_HWEIGHT
181 def_bool y
182
183 config ARCH_MAY_HAVE_PC_FDC
184 def_bool y
185 depends on ISA_DMA_API
186
187 config RWSEM_XCHGADD_ALGORITHM
188 def_bool y
189
190 config GENERIC_CALIBRATE_DELAY
191 def_bool y
192
193 config ARCH_HAS_CPU_RELAX
194 def_bool y
195
196 config ARCH_HAS_CACHE_LINE_SIZE
197 def_bool y
198
199 config HAVE_SETUP_PER_CPU_AREA
200 def_bool y
201
202 config NEED_PER_CPU_EMBED_FIRST_CHUNK
203 def_bool y
204
205 config NEED_PER_CPU_PAGE_FIRST_CHUNK
206 def_bool y
207
208 config ARCH_HIBERNATION_POSSIBLE
209 def_bool y
210
211 config ARCH_SUSPEND_POSSIBLE
212 def_bool y
213
214 config ARCH_WANT_HUGE_PMD_SHARE
215 def_bool y
216
217 config ARCH_WANT_GENERAL_HUGETLB
218 def_bool y
219
220 config ZONE_DMA32
221 bool
222 default X86_64
223
224 config AUDIT_ARCH
225 bool
226 default X86_64
227
228 config ARCH_SUPPORTS_OPTIMIZED_INLINING
229 def_bool y
230
231 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
232 def_bool y
233
234 config HAVE_INTEL_TXT
235 def_bool y
236 depends on INTEL_IOMMU && ACPI
237
238 config X86_32_SMP
239 def_bool y
240 depends on X86_32 && SMP
241
242 config X86_64_SMP
243 def_bool y
244 depends on X86_64 && SMP
245
246 config X86_HT
247 def_bool y
248 depends on SMP
249
250 config X86_32_LAZY_GS
251 def_bool y
252 depends on X86_32 && !CC_STACKPROTECTOR
253
254 config ARCH_HWEIGHT_CFLAGS
255 string
256 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
257 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
258
259 config ARCH_SUPPORTS_UPROBES
260 def_bool y
261
262 source "init/Kconfig"
263 source "kernel/Kconfig.freezer"
264
265 menu "Processor type and features"
266
267 config ZONE_DMA
268 bool "DMA memory allocation support" if EXPERT
269 default y
270 help
271 DMA memory allocation support allows devices with less than 32-bit
272 addressing to allocate within the first 16MB of address space.
273 Disable if no such devices will be used.
274
275 If unsure, say Y.
276
277 config SMP
278 bool "Symmetric multi-processing support"
279 ---help---
280 This enables support for systems with more than one CPU. If you have
281 a system with only one CPU, say N. If you have a system with more
282 than one CPU, say Y.
283
284 If you say N here, the kernel will run on uni- and multiprocessor
285 machines, but will use only one CPU of a multiprocessor machine. If
286 you say Y here, the kernel will run on many, but not all,
287 uniprocessor machines. On a uniprocessor machine, the kernel
288 will run faster if you say N here.
289
290 Note that if you say Y here and choose architecture "586" or
291 "Pentium" under "Processor family", the kernel will not work on 486
292 architectures. Similarly, multiprocessor kernels for the "PPro"
293 architecture may not work on all Pentium based boards.
294
295 People using multiprocessor machines who say Y here should also say
296 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
297 Management" code will be disabled if you say Y here.
298
299 See also <file:Documentation/x86/i386/IO-APIC.txt>,
300 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
301 <http://www.tldp.org/docs.html#howto>.
302
303 If you don't know what to do here, say N.
304
305 config X86_X2APIC
306 bool "Support x2apic"
307 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
308 ---help---
309 This enables x2apic support on CPUs that have this feature.
310
311 This allows 32-bit apic IDs (so it can support very large systems),
312 and accesses the local apic via MSRs not via mmio.
313
314 If you don't know what to do here, say N.
315
316 config X86_MPPARSE
317 bool "Enable MPS table" if ACPI || SFI
318 default y
319 depends on X86_LOCAL_APIC
320 ---help---
321 For old smp systems that do not have proper acpi support. Newer systems
322 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
323
324 config X86_BIGSMP
325 bool "Support for big SMP systems with more than 8 CPUs"
326 depends on X86_32 && SMP
327 ---help---
328 This option is needed for the systems that have more than 8 CPUs
329
330 config GOLDFISH
331 def_bool y
332 depends on X86_GOLDFISH
333
334 if X86_32
335 config X86_EXTENDED_PLATFORM
336 bool "Support for extended (non-PC) x86 platforms"
337 default y
338 ---help---
339 If you disable this option then the kernel will only support
340 standard PC platforms. (which covers the vast majority of
341 systems out there.)
342
343 If you enable this option then you'll be able to select support
344 for the following (non-PC) 32 bit x86 platforms:
345 Goldfish (Android emulator)
346 AMD Elan
347 RDC R-321x SoC
348 SGI 320/540 (Visual Workstation)
349 STA2X11-based (e.g. Northville)
350 Moorestown MID devices
351
352 If you have one of these systems, or if you want to build a
353 generic distribution kernel, say Y here - otherwise say N.
354 endif
355
356 if X86_64
357 config X86_EXTENDED_PLATFORM
358 bool "Support for extended (non-PC) x86 platforms"
359 default y
360 ---help---
361 If you disable this option then the kernel will only support
362 standard PC platforms. (which covers the vast majority of
363 systems out there.)
364
365 If you enable this option then you'll be able to select support
366 for the following (non-PC) 64 bit x86 platforms:
367 Numascale NumaChip
368 ScaleMP vSMP
369 SGI Ultraviolet
370
371 If you have one of these systems, or if you want to build a
372 generic distribution kernel, say Y here - otherwise say N.
373 endif
374 # This is an alphabetically sorted list of 64 bit extended platforms
375 # Please maintain the alphabetic order if and when there are additions
376 config X86_NUMACHIP
377 bool "Numascale NumaChip"
378 depends on X86_64
379 depends on X86_EXTENDED_PLATFORM
380 depends on NUMA
381 depends on SMP
382 depends on X86_X2APIC
383 depends on PCI_MMCONFIG
384 ---help---
385 Adds support for Numascale NumaChip large-SMP systems. Needed to
386 enable more than ~168 cores.
387 If you don't have one of these, you should say N here.
388
389 config X86_VSMP
390 bool "ScaleMP vSMP"
391 select HYPERVISOR_GUEST
392 select PARAVIRT
393 depends on X86_64 && PCI
394 depends on X86_EXTENDED_PLATFORM
395 depends on SMP
396 ---help---
397 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
398 supposed to run on these EM64T-based machines. Only choose this option
399 if you have one of these machines.
400
401 config X86_UV
402 bool "SGI Ultraviolet"
403 depends on X86_64
404 depends on X86_EXTENDED_PLATFORM
405 depends on NUMA
406 depends on X86_X2APIC
407 ---help---
408 This option is needed in order to support SGI Ultraviolet systems.
409 If you don't have one of these, you should say N here.
410
411 # Following is an alphabetically sorted list of 32 bit extended platforms
412 # Please maintain the alphabetic order if and when there are additions
413
414 config X86_GOLDFISH
415 bool "Goldfish (Virtual Platform)"
416 depends on X86_32
417 depends on X86_EXTENDED_PLATFORM
418 ---help---
419 Enable support for the Goldfish virtual platform used primarily
420 for Android development. Unless you are building for the Android
421 Goldfish emulator say N here.
422
423 config X86_INTEL_CE
424 bool "CE4100 TV platform"
425 depends on PCI
426 depends on PCI_GODIRECT
427 depends on X86_32
428 depends on X86_EXTENDED_PLATFORM
429 select X86_REBOOTFIXUPS
430 select OF
431 select OF_EARLY_FLATTREE
432 select IRQ_DOMAIN
433 ---help---
434 Select for the Intel CE media processor (CE4100) SOC.
435 This option compiles in support for the CE4100 SOC for settop
436 boxes and media devices.
437
438 config X86_INTEL_MID
439 bool "Intel MID platform support"
440 depends on X86_32
441 depends on X86_EXTENDED_PLATFORM
442 depends on X86_PLATFORM_DEVICES
443 depends on PCI
444 depends on PCI_GOANY
445 depends on X86_IO_APIC
446 select SFI
447 select I2C
448 select DW_APB_TIMER
449 select APB_TIMER
450 select INTEL_SCU_IPC
451 select MFD_INTEL_MSIC
452 ---help---
453 Select to build a kernel capable of supporting Intel MID (Mobile
454 Internet Device) platform systems which do not have the PCI legacy
455 interfaces. If you are building for a PC class system say N here.
456
457 Intel MID platforms are based on an Intel processor and chipset which
458 consume less power than most of the x86 derivatives.
459
460 config X86_INTEL_LPSS
461 bool "Intel Low Power Subsystem Support"
462 depends on ACPI
463 select COMMON_CLK
464 select PINCTRL
465 ---help---
466 Select to build support for Intel Low Power Subsystem such as
467 found on Intel Lynxpoint PCH. Selecting this option enables
468 things like clock tree (common clock framework) and pincontrol
469 which are needed by the LPSS peripheral drivers.
470
471 config X86_RDC321X
472 bool "RDC R-321x SoC"
473 depends on X86_32
474 depends on X86_EXTENDED_PLATFORM
475 select M486
476 select X86_REBOOTFIXUPS
477 ---help---
478 This option is needed for RDC R-321x system-on-chip, also known
479 as R-8610-(G).
480 If you don't have one of these chips, you should say N here.
481
482 config X86_32_NON_STANDARD
483 bool "Support non-standard 32-bit SMP architectures"
484 depends on X86_32 && SMP
485 depends on X86_EXTENDED_PLATFORM
486 ---help---
487 This option compiles in the bigsmp and STA2X11 default
488 subarchitectures. It is intended for a generic binary
489 kernel. If you select them all, kernel will probe it one by
490 one and will fallback to default.
491
492 # Alphabetically sorted list of Non standard 32 bit platforms
493
494 config X86_SUPPORTS_MEMORY_FAILURE
495 def_bool y
496 # MCE code calls memory_failure():
497 depends on X86_MCE
498 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
499 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
500 depends on X86_64 || !SPARSEMEM
501 select ARCH_SUPPORTS_MEMORY_FAILURE
502
503 config STA2X11
504 bool "STA2X11 Companion Chip Support"
505 depends on X86_32_NON_STANDARD && PCI
506 select X86_DEV_DMA_OPS
507 select X86_DMA_REMAP
508 select SWIOTLB
509 select MFD_STA2X11
510 select ARCH_REQUIRE_GPIOLIB
511 default n
512 ---help---
513 This adds support for boards based on the STA2X11 IO-Hub,
514 a.k.a. "ConneXt". The chip is used in place of the standard
515 PC chipset, so all "standard" peripherals are missing. If this
516 option is selected the kernel will still be able to boot on
517 standard PC machines.
518
519 config X86_32_IRIS
520 tristate "Eurobraille/Iris poweroff module"
521 depends on X86_32
522 ---help---
523 The Iris machines from EuroBraille do not have APM or ACPI support
524 to shut themselves down properly. A special I/O sequence is
525 needed to do so, which is what this module does at
526 kernel shutdown.
527
528 This is only for Iris machines from EuroBraille.
529
530 If unused, say N.
531
532 config SCHED_OMIT_FRAME_POINTER
533 def_bool y
534 prompt "Single-depth WCHAN output"
535 depends on X86
536 ---help---
537 Calculate simpler /proc/<PID>/wchan values. If this option
538 is disabled then wchan values will recurse back to the
539 caller function. This provides more accurate wchan values,
540 at the expense of slightly more scheduling overhead.
541
542 If in doubt, say "Y".
543
544 menuconfig HYPERVISOR_GUEST
545 bool "Linux guest support"
546 ---help---
547 Say Y here to enable options for running Linux under various hyper-
548 visors. This option enables basic hypervisor detection and platform
549 setup.
550
551 If you say N, all options in this submenu will be skipped and
552 disabled, and Linux guest support won't be built in.
553
554 if HYPERVISOR_GUEST
555
556 config PARAVIRT
557 bool "Enable paravirtualization code"
558 ---help---
559 This changes the kernel so it can modify itself when it is run
560 under a hypervisor, potentially improving performance significantly
561 over full virtualization. However, when run without a hypervisor
562 the kernel is theoretically slower and slightly larger.
563
564 config PARAVIRT_DEBUG
565 bool "paravirt-ops debugging"
566 depends on PARAVIRT && DEBUG_KERNEL
567 ---help---
568 Enable to debug paravirt_ops internals. Specifically, BUG if
569 a paravirt_op is missing when it is called.
570
571 config PARAVIRT_SPINLOCKS
572 bool "Paravirtualization layer for spinlocks"
573 depends on PARAVIRT && SMP
574 select UNINLINE_SPIN_UNLOCK
575 ---help---
576 Paravirtualized spinlocks allow a pvops backend to replace the
577 spinlock implementation with something virtualization-friendly
578 (for example, block the virtual CPU rather than spinning).
579
580 It has a minimal impact on native kernels and gives a nice performance
581 benefit on paravirtualized KVM / Xen kernels.
582
583 If you are unsure how to answer this question, answer Y.
584
585 source "arch/x86/xen/Kconfig"
586
587 config KVM_GUEST
588 bool "KVM Guest support (including kvmclock)"
589 depends on PARAVIRT
590 select PARAVIRT_CLOCK
591 default y
592 ---help---
593 This option enables various optimizations for running under the KVM
594 hypervisor. It includes a paravirtualized clock, so that instead
595 of relying on a PIT (or probably other) emulation by the
596 underlying device model, the host provides the guest with
597 timing infrastructure such as time of day, and system time
598
599 config KVM_DEBUG_FS
600 bool "Enable debug information for KVM Guests in debugfs"
601 depends on KVM_GUEST && DEBUG_FS
602 default n
603 ---help---
604 This option enables collection of various statistics for KVM guest.
605 Statistics are displayed in debugfs filesystem. Enabling this option
606 may incur significant overhead.
607
608 source "arch/x86/lguest/Kconfig"
609
610 config PARAVIRT_TIME_ACCOUNTING
611 bool "Paravirtual steal time accounting"
612 depends on PARAVIRT
613 default n
614 ---help---
615 Select this option to enable fine granularity task steal time
616 accounting. Time spent executing other tasks in parallel with
617 the current vCPU is discounted from the vCPU power. To account for
618 that, there can be a small performance impact.
619
620 If in doubt, say N here.
621
622 config PARAVIRT_CLOCK
623 bool
624
625 endif #HYPERVISOR_GUEST
626
627 config NO_BOOTMEM
628 def_bool y
629
630 config MEMTEST
631 bool "Memtest"
632 ---help---
633 This option adds a kernel parameter 'memtest', which allows memtest
634 to be set.
635 memtest=0, mean disabled; -- default
636 memtest=1, mean do 1 test pattern;
637 ...
638 memtest=4, mean do 4 test patterns.
639 If you are unsure how to answer this question, answer N.
640
641 source "arch/x86/Kconfig.cpu"
642
643 config HPET_TIMER
644 def_bool X86_64
645 prompt "HPET Timer Support" if X86_32
646 ---help---
647 Use the IA-PC HPET (High Precision Event Timer) to manage
648 time in preference to the PIT and RTC, if a HPET is
649 present.
650 HPET is the next generation timer replacing legacy 8254s.
651 The HPET provides a stable time base on SMP
652 systems, unlike the TSC, but it is more expensive to access,
653 as it is off-chip. You can find the HPET spec at
654 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
655
656 You can safely choose Y here. However, HPET will only be
657 activated if the platform and the BIOS support this feature.
658 Otherwise the 8254 will be used for timing services.
659
660 Choose N to continue using the legacy 8254 timer.
661
662 config HPET_EMULATE_RTC
663 def_bool y
664 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
665
666 config APB_TIMER
667 def_bool y if X86_INTEL_MID
668 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
669 select DW_APB_TIMER
670 depends on X86_INTEL_MID && SFI
671 help
672 APB timer is the replacement for 8254, HPET on X86 MID platforms.
673 The APBT provides a stable time base on SMP
674 systems, unlike the TSC, but it is more expensive to access,
675 as it is off-chip. APB timers are always running regardless of CPU
676 C states, they are used as per CPU clockevent device when possible.
677
678 # Mark as expert because too many people got it wrong.
679 # The code disables itself when not needed.
680 config DMI
681 default y
682 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
683 bool "Enable DMI scanning" if EXPERT
684 ---help---
685 Enabled scanning of DMI to identify machine quirks. Say Y
686 here unless you have verified that your setup is not
687 affected by entries in the DMI blacklist. Required by PNP
688 BIOS code.
689
690 config GART_IOMMU
691 bool "Old AMD GART IOMMU support"
692 select SWIOTLB
693 depends on X86_64 && PCI && AMD_NB
694 ---help---
695 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
696 GART based hardware IOMMUs.
697
698 The GART supports full DMA access for devices with 32-bit access
699 limitations, on systems with more than 3 GB. This is usually needed
700 for USB, sound, many IDE/SATA chipsets and some other devices.
701
702 Newer systems typically have a modern AMD IOMMU, supported via
703 the CONFIG_AMD_IOMMU=y config option.
704
705 In normal configurations this driver is only active when needed:
706 there's more than 3 GB of memory and the system contains a
707 32-bit limited device.
708
709 If unsure, say Y.
710
711 config CALGARY_IOMMU
712 bool "IBM Calgary IOMMU support"
713 select SWIOTLB
714 depends on X86_64 && PCI
715 ---help---
716 Support for hardware IOMMUs in IBM's xSeries x366 and x460
717 systems. Needed to run systems with more than 3GB of memory
718 properly with 32-bit PCI devices that do not support DAC
719 (Double Address Cycle). Calgary also supports bus level
720 isolation, where all DMAs pass through the IOMMU. This
721 prevents them from going anywhere except their intended
722 destination. This catches hard-to-find kernel bugs and
723 mis-behaving drivers and devices that do not use the DMA-API
724 properly to set up their DMA buffers. The IOMMU can be
725 turned off at boot time with the iommu=off parameter.
726 Normally the kernel will make the right choice by itself.
727 If unsure, say Y.
728
729 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
730 def_bool y
731 prompt "Should Calgary be enabled by default?"
732 depends on CALGARY_IOMMU
733 ---help---
734 Should Calgary be enabled by default? if you choose 'y', Calgary
735 will be used (if it exists). If you choose 'n', Calgary will not be
736 used even if it exists. If you choose 'n' and would like to use
737 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
738 If unsure, say Y.
739
740 # need this always selected by IOMMU for the VIA workaround
741 config SWIOTLB
742 def_bool y if X86_64
743 ---help---
744 Support for software bounce buffers used on x86-64 systems
745 which don't have a hardware IOMMU. Using this PCI devices
746 which can only access 32-bits of memory can be used on systems
747 with more than 3 GB of memory.
748 If unsure, say Y.
749
750 config IOMMU_HELPER
751 def_bool y
752 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
753
754 config MAXSMP
755 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
756 depends on X86_64 && SMP && DEBUG_KERNEL
757 select CPUMASK_OFFSTACK
758 ---help---
759 Enable maximum number of CPUS and NUMA Nodes for this architecture.
760 If unsure, say N.
761
762 config NR_CPUS
763 int "Maximum number of CPUs" if SMP && !MAXSMP
764 range 2 8 if SMP && X86_32 && !X86_BIGSMP
765 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
766 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
767 default "1" if !SMP
768 default "8192" if MAXSMP
769 default "32" if SMP && X86_BIGSMP
770 default "8" if SMP
771 ---help---
772 This allows you to specify the maximum number of CPUs which this
773 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
774 supported value is 4096, otherwise the maximum value is 512. The
775 minimum value which makes sense is 2.
776
777 This is purely to save memory - each supported CPU adds
778 approximately eight kilobytes to the kernel image.
779
780 config SCHED_SMT
781 bool "SMT (Hyperthreading) scheduler support"
782 depends on X86_HT
783 ---help---
784 SMT scheduler support improves the CPU scheduler's decision making
785 when dealing with Intel Pentium 4 chips with HyperThreading at a
786 cost of slightly increased overhead in some places. If unsure say
787 N here.
788
789 config SCHED_MC
790 def_bool y
791 prompt "Multi-core scheduler support"
792 depends on X86_HT
793 ---help---
794 Multi-core scheduler support improves the CPU scheduler's decision
795 making when dealing with multi-core CPU chips at a cost of slightly
796 increased overhead in some places. If unsure say N here.
797
798 source "kernel/Kconfig.preempt"
799
800 config X86_UP_APIC
801 bool "Local APIC support on uniprocessors"
802 depends on X86_32 && !SMP && !X86_32_NON_STANDARD && !PCI_MSI
803 ---help---
804 A local APIC (Advanced Programmable Interrupt Controller) is an
805 integrated interrupt controller in the CPU. If you have a single-CPU
806 system which has a processor with a local APIC, you can say Y here to
807 enable and use it. If you say Y here even though your machine doesn't
808 have a local APIC, then the kernel will still run with no slowdown at
809 all. The local APIC supports CPU-generated self-interrupts (timer,
810 performance counters), and the NMI watchdog which detects hard
811 lockups.
812
813 config X86_UP_IOAPIC
814 bool "IO-APIC support on uniprocessors"
815 depends on X86_UP_APIC
816 ---help---
817 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
818 SMP-capable replacement for PC-style interrupt controllers. Most
819 SMP systems and many recent uniprocessor systems have one.
820
821 If you have a single-CPU system with an IO-APIC, you can say Y here
822 to use it. If you say Y here even though your machine doesn't have
823 an IO-APIC, then the kernel will still run with no slowdown at all.
824
825 config X86_LOCAL_APIC
826 def_bool y
827 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
828
829 config X86_IO_APIC
830 def_bool y
831 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC || PCI_MSI
832
833 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
834 bool "Reroute for broken boot IRQs"
835 depends on X86_IO_APIC
836 ---help---
837 This option enables a workaround that fixes a source of
838 spurious interrupts. This is recommended when threaded
839 interrupt handling is used on systems where the generation of
840 superfluous "boot interrupts" cannot be disabled.
841
842 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
843 entry in the chipset's IO-APIC is masked (as, e.g. the RT
844 kernel does during interrupt handling). On chipsets where this
845 boot IRQ generation cannot be disabled, this workaround keeps
846 the original IRQ line masked so that only the equivalent "boot
847 IRQ" is delivered to the CPUs. The workaround also tells the
848 kernel to set up the IRQ handler on the boot IRQ line. In this
849 way only one interrupt is delivered to the kernel. Otherwise
850 the spurious second interrupt may cause the kernel to bring
851 down (vital) interrupt lines.
852
853 Only affects "broken" chipsets. Interrupt sharing may be
854 increased on these systems.
855
856 config X86_MCE
857 bool "Machine Check / overheating reporting"
858 default y
859 ---help---
860 Machine Check support allows the processor to notify the
861 kernel if it detects a problem (e.g. overheating, data corruption).
862 The action the kernel takes depends on the severity of the problem,
863 ranging from warning messages to halting the machine.
864
865 config X86_MCE_INTEL
866 def_bool y
867 prompt "Intel MCE features"
868 depends on X86_MCE && X86_LOCAL_APIC
869 ---help---
870 Additional support for intel specific MCE features such as
871 the thermal monitor.
872
873 config X86_MCE_AMD
874 def_bool y
875 prompt "AMD MCE features"
876 depends on X86_MCE && X86_LOCAL_APIC
877 ---help---
878 Additional support for AMD specific MCE features such as
879 the DRAM Error Threshold.
880
881 config X86_ANCIENT_MCE
882 bool "Support for old Pentium 5 / WinChip machine checks"
883 depends on X86_32 && X86_MCE
884 ---help---
885 Include support for machine check handling on old Pentium 5 or WinChip
886 systems. These typically need to be enabled explicitly on the command
887 line.
888
889 config X86_MCE_THRESHOLD
890 depends on X86_MCE_AMD || X86_MCE_INTEL
891 def_bool y
892
893 config X86_MCE_INJECT
894 depends on X86_MCE
895 tristate "Machine check injector support"
896 ---help---
897 Provide support for injecting machine checks for testing purposes.
898 If you don't know what a machine check is and you don't do kernel
899 QA it is safe to say n.
900
901 config X86_THERMAL_VECTOR
902 def_bool y
903 depends on X86_MCE_INTEL
904
905 config VM86
906 bool "Enable VM86 support" if EXPERT
907 default y
908 depends on X86_32
909 ---help---
910 This option is required by programs like DOSEMU to run 16-bit legacy
911 code on X86 processors. It also may be needed by software like
912 XFree86 to initialize some video cards via BIOS. Disabling this
913 option saves about 6k.
914
915 config TOSHIBA
916 tristate "Toshiba Laptop support"
917 depends on X86_32
918 ---help---
919 This adds a driver to safely access the System Management Mode of
920 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
921 not work on models with a Phoenix BIOS. The System Management Mode
922 is used to set the BIOS and power saving options on Toshiba portables.
923
924 For information on utilities to make use of this driver see the
925 Toshiba Linux utilities web site at:
926 <http://www.buzzard.org.uk/toshiba/>.
927
928 Say Y if you intend to run this kernel on a Toshiba portable.
929 Say N otherwise.
930
931 config I8K
932 tristate "Dell laptop support"
933 select HWMON
934 ---help---
935 This adds a driver to safely access the System Management Mode
936 of the CPU on the Dell Inspiron 8000. The System Management Mode
937 is used to read cpu temperature and cooling fan status and to
938 control the fans on the I8K portables.
939
940 This driver has been tested only on the Inspiron 8000 but it may
941 also work with other Dell laptops. You can force loading on other
942 models by passing the parameter `force=1' to the module. Use at
943 your own risk.
944
945 For information on utilities to make use of this driver see the
946 I8K Linux utilities web site at:
947 <http://people.debian.org/~dz/i8k/>
948
949 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
950 Say N otherwise.
951
952 config X86_REBOOTFIXUPS
953 bool "Enable X86 board specific fixups for reboot"
954 depends on X86_32
955 ---help---
956 This enables chipset and/or board specific fixups to be done
957 in order to get reboot to work correctly. This is only needed on
958 some combinations of hardware and BIOS. The symptom, for which
959 this config is intended, is when reboot ends with a stalled/hung
960 system.
961
962 Currently, the only fixup is for the Geode machines using
963 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
964
965 Say Y if you want to enable the fixup. Currently, it's safe to
966 enable this option even if you don't need it.
967 Say N otherwise.
968
969 config MICROCODE
970 tristate "CPU microcode loading support"
971 depends on CPU_SUP_AMD || CPU_SUP_INTEL
972 select FW_LOADER
973 ---help---
974
975 If you say Y here, you will be able to update the microcode on
976 certain Intel and AMD processors. The Intel support is for the
977 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
978 Xeon etc. The AMD support is for families 0x10 and later. You will
979 obviously need the actual microcode binary data itself which is not
980 shipped with the Linux kernel.
981
982 This option selects the general module only, you need to select
983 at least one vendor specific module as well.
984
985 To compile this driver as a module, choose M here: the module
986 will be called microcode.
987
988 config MICROCODE_INTEL
989 bool "Intel microcode loading support"
990 depends on MICROCODE
991 default MICROCODE
992 select FW_LOADER
993 ---help---
994 This options enables microcode patch loading support for Intel
995 processors.
996
997 For the current Intel microcode data package go to
998 <https://downloadcenter.intel.com> and search for
999 'Linux Processor Microcode Data File'.
1000
1001 config MICROCODE_AMD
1002 bool "AMD microcode loading support"
1003 depends on MICROCODE
1004 select FW_LOADER
1005 ---help---
1006 If you select this option, microcode patch loading support for AMD
1007 processors will be enabled.
1008
1009 config MICROCODE_OLD_INTERFACE
1010 def_bool y
1011 depends on MICROCODE
1012
1013 config MICROCODE_INTEL_EARLY
1014 def_bool n
1015
1016 config MICROCODE_AMD_EARLY
1017 def_bool n
1018
1019 config MICROCODE_EARLY
1020 bool "Early load microcode"
1021 depends on MICROCODE=y && BLK_DEV_INITRD
1022 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1023 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1024 default y
1025 help
1026 This option provides functionality to read additional microcode data
1027 at the beginning of initrd image. The data tells kernel to load
1028 microcode to CPU's as early as possible. No functional change if no
1029 microcode data is glued to the initrd, therefore it's safe to say Y.
1030
1031 config X86_MSR
1032 tristate "/dev/cpu/*/msr - Model-specific register support"
1033 ---help---
1034 This device gives privileged processes access to the x86
1035 Model-Specific Registers (MSRs). It is a character device with
1036 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1037 MSR accesses are directed to a specific CPU on multi-processor
1038 systems.
1039
1040 config X86_CPUID
1041 tristate "/dev/cpu/*/cpuid - CPU information support"
1042 ---help---
1043 This device gives processes access to the x86 CPUID instruction to
1044 be executed on a specific processor. It is a character device
1045 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1046 /dev/cpu/31/cpuid.
1047
1048 choice
1049 prompt "High Memory Support"
1050 default HIGHMEM4G
1051 depends on X86_32
1052
1053 config NOHIGHMEM
1054 bool "off"
1055 ---help---
1056 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1057 However, the address space of 32-bit x86 processors is only 4
1058 Gigabytes large. That means that, if you have a large amount of
1059 physical memory, not all of it can be "permanently mapped" by the
1060 kernel. The physical memory that's not permanently mapped is called
1061 "high memory".
1062
1063 If you are compiling a kernel which will never run on a machine with
1064 more than 1 Gigabyte total physical RAM, answer "off" here (default
1065 choice and suitable for most users). This will result in a "3GB/1GB"
1066 split: 3GB are mapped so that each process sees a 3GB virtual memory
1067 space and the remaining part of the 4GB virtual memory space is used
1068 by the kernel to permanently map as much physical memory as
1069 possible.
1070
1071 If the machine has between 1 and 4 Gigabytes physical RAM, then
1072 answer "4GB" here.
1073
1074 If more than 4 Gigabytes is used then answer "64GB" here. This
1075 selection turns Intel PAE (Physical Address Extension) mode on.
1076 PAE implements 3-level paging on IA32 processors. PAE is fully
1077 supported by Linux, PAE mode is implemented on all recent Intel
1078 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1079 then the kernel will not boot on CPUs that don't support PAE!
1080
1081 The actual amount of total physical memory will either be
1082 auto detected or can be forced by using a kernel command line option
1083 such as "mem=256M". (Try "man bootparam" or see the documentation of
1084 your boot loader (lilo or loadlin) about how to pass options to the
1085 kernel at boot time.)
1086
1087 If unsure, say "off".
1088
1089 config HIGHMEM4G
1090 bool "4GB"
1091 ---help---
1092 Select this if you have a 32-bit processor and between 1 and 4
1093 gigabytes of physical RAM.
1094
1095 config HIGHMEM64G
1096 bool "64GB"
1097 depends on !M486
1098 select X86_PAE
1099 ---help---
1100 Select this if you have a 32-bit processor and more than 4
1101 gigabytes of physical RAM.
1102
1103 endchoice
1104
1105 choice
1106 prompt "Memory split" if EXPERT
1107 default VMSPLIT_3G
1108 depends on X86_32
1109 ---help---
1110 Select the desired split between kernel and user memory.
1111
1112 If the address range available to the kernel is less than the
1113 physical memory installed, the remaining memory will be available
1114 as "high memory". Accessing high memory is a little more costly
1115 than low memory, as it needs to be mapped into the kernel first.
1116 Note that increasing the kernel address space limits the range
1117 available to user programs, making the address space there
1118 tighter. Selecting anything other than the default 3G/1G split
1119 will also likely make your kernel incompatible with binary-only
1120 kernel modules.
1121
1122 If you are not absolutely sure what you are doing, leave this
1123 option alone!
1124
1125 config VMSPLIT_3G
1126 bool "3G/1G user/kernel split"
1127 config VMSPLIT_3G_OPT
1128 depends on !X86_PAE
1129 bool "3G/1G user/kernel split (for full 1G low memory)"
1130 config VMSPLIT_2G
1131 bool "2G/2G user/kernel split"
1132 config VMSPLIT_2G_OPT
1133 depends on !X86_PAE
1134 bool "2G/2G user/kernel split (for full 2G low memory)"
1135 config VMSPLIT_1G
1136 bool "1G/3G user/kernel split"
1137 endchoice
1138
1139 config PAGE_OFFSET
1140 hex
1141 default 0xB0000000 if VMSPLIT_3G_OPT
1142 default 0x80000000 if VMSPLIT_2G
1143 default 0x78000000 if VMSPLIT_2G_OPT
1144 default 0x40000000 if VMSPLIT_1G
1145 default 0xC0000000
1146 depends on X86_32
1147
1148 config HIGHMEM
1149 def_bool y
1150 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1151
1152 config X86_PAE
1153 bool "PAE (Physical Address Extension) Support"
1154 depends on X86_32 && !HIGHMEM4G
1155 ---help---
1156 PAE is required for NX support, and furthermore enables
1157 larger swapspace support for non-overcommit purposes. It
1158 has the cost of more pagetable lookup overhead, and also
1159 consumes more pagetable space per process.
1160
1161 config ARCH_PHYS_ADDR_T_64BIT
1162 def_bool y
1163 depends on X86_64 || X86_PAE
1164
1165 config ARCH_DMA_ADDR_T_64BIT
1166 def_bool y
1167 depends on X86_64 || HIGHMEM64G
1168
1169 config DIRECT_GBPAGES
1170 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1171 default y
1172 depends on X86_64
1173 ---help---
1174 Allow the kernel linear mapping to use 1GB pages on CPUs that
1175 support it. This can improve the kernel's performance a tiny bit by
1176 reducing TLB pressure. If in doubt, say "Y".
1177
1178 # Common NUMA Features
1179 config NUMA
1180 bool "Numa Memory Allocation and Scheduler Support"
1181 depends on SMP
1182 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1183 default y if X86_BIGSMP
1184 ---help---
1185 Enable NUMA (Non Uniform Memory Access) support.
1186
1187 The kernel will try to allocate memory used by a CPU on the
1188 local memory controller of the CPU and add some more
1189 NUMA awareness to the kernel.
1190
1191 For 64-bit this is recommended if the system is Intel Core i7
1192 (or later), AMD Opteron, or EM64T NUMA.
1193
1194 For 32-bit this is only needed if you boot a 32-bit
1195 kernel on a 64-bit NUMA platform.
1196
1197 Otherwise, you should say N.
1198
1199 config AMD_NUMA
1200 def_bool y
1201 prompt "Old style AMD Opteron NUMA detection"
1202 depends on X86_64 && NUMA && PCI
1203 ---help---
1204 Enable AMD NUMA node topology detection. You should say Y here if
1205 you have a multi processor AMD system. This uses an old method to
1206 read the NUMA configuration directly from the builtin Northbridge
1207 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1208 which also takes priority if both are compiled in.
1209
1210 config X86_64_ACPI_NUMA
1211 def_bool y
1212 prompt "ACPI NUMA detection"
1213 depends on X86_64 && NUMA && ACPI && PCI
1214 select ACPI_NUMA
1215 ---help---
1216 Enable ACPI SRAT based node topology detection.
1217
1218 # Some NUMA nodes have memory ranges that span
1219 # other nodes. Even though a pfn is valid and
1220 # between a node's start and end pfns, it may not
1221 # reside on that node. See memmap_init_zone()
1222 # for details.
1223 config NODES_SPAN_OTHER_NODES
1224 def_bool y
1225 depends on X86_64_ACPI_NUMA
1226
1227 config NUMA_EMU
1228 bool "NUMA emulation"
1229 depends on NUMA
1230 ---help---
1231 Enable NUMA emulation. A flat machine will be split
1232 into virtual nodes when booted with "numa=fake=N", where N is the
1233 number of nodes. This is only useful for debugging.
1234
1235 config NODES_SHIFT
1236 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1237 range 1 10
1238 default "10" if MAXSMP
1239 default "6" if X86_64
1240 default "3"
1241 depends on NEED_MULTIPLE_NODES
1242 ---help---
1243 Specify the maximum number of NUMA Nodes available on the target
1244 system. Increases memory reserved to accommodate various tables.
1245
1246 config ARCH_HAVE_MEMORY_PRESENT
1247 def_bool y
1248 depends on X86_32 && DISCONTIGMEM
1249
1250 config NEED_NODE_MEMMAP_SIZE
1251 def_bool y
1252 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1253
1254 config ARCH_FLATMEM_ENABLE
1255 def_bool y
1256 depends on X86_32 && !NUMA
1257
1258 config ARCH_DISCONTIGMEM_ENABLE
1259 def_bool y
1260 depends on NUMA && X86_32
1261
1262 config ARCH_DISCONTIGMEM_DEFAULT
1263 def_bool y
1264 depends on NUMA && X86_32
1265
1266 config ARCH_SPARSEMEM_ENABLE
1267 def_bool y
1268 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1269 select SPARSEMEM_STATIC if X86_32
1270 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1271
1272 config ARCH_SPARSEMEM_DEFAULT
1273 def_bool y
1274 depends on X86_64
1275
1276 config ARCH_SELECT_MEMORY_MODEL
1277 def_bool y
1278 depends on ARCH_SPARSEMEM_ENABLE
1279
1280 config ARCH_MEMORY_PROBE
1281 bool "Enable sysfs memory/probe interface"
1282 depends on X86_64 && MEMORY_HOTPLUG
1283 help
1284 This option enables a sysfs memory/probe interface for testing.
1285 See Documentation/memory-hotplug.txt for more information.
1286 If you are unsure how to answer this question, answer N.
1287
1288 config ARCH_PROC_KCORE_TEXT
1289 def_bool y
1290 depends on X86_64 && PROC_KCORE
1291
1292 config ILLEGAL_POINTER_VALUE
1293 hex
1294 default 0 if X86_32
1295 default 0xdead000000000000 if X86_64
1296
1297 source "mm/Kconfig"
1298
1299 config HIGHPTE
1300 bool "Allocate 3rd-level pagetables from highmem"
1301 depends on HIGHMEM
1302 ---help---
1303 The VM uses one page table entry for each page of physical memory.
1304 For systems with a lot of RAM, this can be wasteful of precious
1305 low memory. Setting this option will put user-space page table
1306 entries in high memory.
1307
1308 config X86_CHECK_BIOS_CORRUPTION
1309 bool "Check for low memory corruption"
1310 ---help---
1311 Periodically check for memory corruption in low memory, which
1312 is suspected to be caused by BIOS. Even when enabled in the
1313 configuration, it is disabled at runtime. Enable it by
1314 setting "memory_corruption_check=1" on the kernel command
1315 line. By default it scans the low 64k of memory every 60
1316 seconds; see the memory_corruption_check_size and
1317 memory_corruption_check_period parameters in
1318 Documentation/kernel-parameters.txt to adjust this.
1319
1320 When enabled with the default parameters, this option has
1321 almost no overhead, as it reserves a relatively small amount
1322 of memory and scans it infrequently. It both detects corruption
1323 and prevents it from affecting the running system.
1324
1325 It is, however, intended as a diagnostic tool; if repeatable
1326 BIOS-originated corruption always affects the same memory,
1327 you can use memmap= to prevent the kernel from using that
1328 memory.
1329
1330 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1331 bool "Set the default setting of memory_corruption_check"
1332 depends on X86_CHECK_BIOS_CORRUPTION
1333 default y
1334 ---help---
1335 Set whether the default state of memory_corruption_check is
1336 on or off.
1337
1338 config X86_RESERVE_LOW
1339 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1340 default 64
1341 range 4 640
1342 ---help---
1343 Specify the amount of low memory to reserve for the BIOS.
1344
1345 The first page contains BIOS data structures that the kernel
1346 must not use, so that page must always be reserved.
1347
1348 By default we reserve the first 64K of physical RAM, as a
1349 number of BIOSes are known to corrupt that memory range
1350 during events such as suspend/resume or monitor cable
1351 insertion, so it must not be used by the kernel.
1352
1353 You can set this to 4 if you are absolutely sure that you
1354 trust the BIOS to get all its memory reservations and usages
1355 right. If you know your BIOS have problems beyond the
1356 default 64K area, you can set this to 640 to avoid using the
1357 entire low memory range.
1358
1359 If you have doubts about the BIOS (e.g. suspend/resume does
1360 not work or there's kernel crashes after certain hardware
1361 hotplug events) then you might want to enable
1362 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1363 typical corruption patterns.
1364
1365 Leave this to the default value of 64 if you are unsure.
1366
1367 config MATH_EMULATION
1368 bool
1369 prompt "Math emulation" if X86_32
1370 ---help---
1371 Linux can emulate a math coprocessor (used for floating point
1372 operations) if you don't have one. 486DX and Pentium processors have
1373 a math coprocessor built in, 486SX and 386 do not, unless you added
1374 a 487DX or 387, respectively. (The messages during boot time can
1375 give you some hints here ["man dmesg"].) Everyone needs either a
1376 coprocessor or this emulation.
1377
1378 If you don't have a math coprocessor, you need to say Y here; if you
1379 say Y here even though you have a coprocessor, the coprocessor will
1380 be used nevertheless. (This behavior can be changed with the kernel
1381 command line option "no387", which comes handy if your coprocessor
1382 is broken. Try "man bootparam" or see the documentation of your boot
1383 loader (lilo or loadlin) about how to pass options to the kernel at
1384 boot time.) This means that it is a good idea to say Y here if you
1385 intend to use this kernel on different machines.
1386
1387 More information about the internals of the Linux math coprocessor
1388 emulation can be found in <file:arch/x86/math-emu/README>.
1389
1390 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1391 kernel, it won't hurt.
1392
1393 config MTRR
1394 def_bool y
1395 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1396 ---help---
1397 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1398 the Memory Type Range Registers (MTRRs) may be used to control
1399 processor access to memory ranges. This is most useful if you have
1400 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1401 allows bus write transfers to be combined into a larger transfer
1402 before bursting over the PCI/AGP bus. This can increase performance
1403 of image write operations 2.5 times or more. Saying Y here creates a
1404 /proc/mtrr file which may be used to manipulate your processor's
1405 MTRRs. Typically the X server should use this.
1406
1407 This code has a reasonably generic interface so that similar
1408 control registers on other processors can be easily supported
1409 as well:
1410
1411 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1412 Registers (ARRs) which provide a similar functionality to MTRRs. For
1413 these, the ARRs are used to emulate the MTRRs.
1414 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1415 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1416 write-combining. All of these processors are supported by this code
1417 and it makes sense to say Y here if you have one of them.
1418
1419 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1420 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1421 can lead to all sorts of problems, so it's good to say Y here.
1422
1423 You can safely say Y even if your machine doesn't have MTRRs, you'll
1424 just add about 9 KB to your kernel.
1425
1426 See <file:Documentation/x86/mtrr.txt> for more information.
1427
1428 config MTRR_SANITIZER
1429 def_bool y
1430 prompt "MTRR cleanup support"
1431 depends on MTRR
1432 ---help---
1433 Convert MTRR layout from continuous to discrete, so X drivers can
1434 add writeback entries.
1435
1436 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1437 The largest mtrr entry size for a continuous block can be set with
1438 mtrr_chunk_size.
1439
1440 If unsure, say Y.
1441
1442 config MTRR_SANITIZER_ENABLE_DEFAULT
1443 int "MTRR cleanup enable value (0-1)"
1444 range 0 1
1445 default "0"
1446 depends on MTRR_SANITIZER
1447 ---help---
1448 Enable mtrr cleanup default value
1449
1450 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1451 int "MTRR cleanup spare reg num (0-7)"
1452 range 0 7
1453 default "1"
1454 depends on MTRR_SANITIZER
1455 ---help---
1456 mtrr cleanup spare entries default, it can be changed via
1457 mtrr_spare_reg_nr=N on the kernel command line.
1458
1459 config X86_PAT
1460 def_bool y
1461 prompt "x86 PAT support" if EXPERT
1462 depends on MTRR
1463 ---help---
1464 Use PAT attributes to setup page level cache control.
1465
1466 PATs are the modern equivalents of MTRRs and are much more
1467 flexible than MTRRs.
1468
1469 Say N here if you see bootup problems (boot crash, boot hang,
1470 spontaneous reboots) or a non-working video driver.
1471
1472 If unsure, say Y.
1473
1474 config ARCH_USES_PG_UNCACHED
1475 def_bool y
1476 depends on X86_PAT
1477
1478 config ARCH_RANDOM
1479 def_bool y
1480 prompt "x86 architectural random number generator" if EXPERT
1481 ---help---
1482 Enable the x86 architectural RDRAND instruction
1483 (Intel Bull Mountain technology) to generate random numbers.
1484 If supported, this is a high bandwidth, cryptographically
1485 secure hardware random number generator.
1486
1487 config X86_SMAP
1488 def_bool y
1489 prompt "Supervisor Mode Access Prevention" if EXPERT
1490 ---help---
1491 Supervisor Mode Access Prevention (SMAP) is a security
1492 feature in newer Intel processors. There is a small
1493 performance cost if this enabled and turned on; there is
1494 also a small increase in the kernel size if this is enabled.
1495
1496 If unsure, say Y.
1497
1498 config EFI
1499 bool "EFI runtime service support"
1500 depends on ACPI
1501 select UCS2_STRING
1502 ---help---
1503 This enables the kernel to use EFI runtime services that are
1504 available (such as the EFI variable services).
1505
1506 This option is only useful on systems that have EFI firmware.
1507 In addition, you should use the latest ELILO loader available
1508 at <http://elilo.sourceforge.net> in order to take advantage
1509 of EFI runtime services. However, even with this option, the
1510 resultant kernel should continue to boot on existing non-EFI
1511 platforms.
1512
1513 config EFI_STUB
1514 bool "EFI stub support"
1515 depends on EFI
1516 ---help---
1517 This kernel feature allows a bzImage to be loaded directly
1518 by EFI firmware without the use of a bootloader.
1519
1520 See Documentation/efi-stub.txt for more information.
1521
1522 config EFI_MIXED
1523 bool "EFI mixed-mode support"
1524 depends on EFI_STUB && X86_64
1525 ---help---
1526 Enabling this feature allows a 64-bit kernel to be booted
1527 on a 32-bit firmware, provided that your CPU supports 64-bit
1528 mode.
1529
1530 Note that it is not possible to boot a mixed-mode enabled
1531 kernel via the EFI boot stub - a bootloader that supports
1532 the EFI handover protocol must be used.
1533
1534 If unsure, say N.
1535
1536 config SECCOMP
1537 def_bool y
1538 prompt "Enable seccomp to safely compute untrusted bytecode"
1539 ---help---
1540 This kernel feature is useful for number crunching applications
1541 that may need to compute untrusted bytecode during their
1542 execution. By using pipes or other transports made available to
1543 the process as file descriptors supporting the read/write
1544 syscalls, it's possible to isolate those applications in
1545 their own address space using seccomp. Once seccomp is
1546 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1547 and the task is only allowed to execute a few safe syscalls
1548 defined by each seccomp mode.
1549
1550 If unsure, say Y. Only embedded should say N here.
1551
1552 source kernel/Kconfig.hz
1553
1554 config KEXEC
1555 bool "kexec system call"
1556 ---help---
1557 kexec is a system call that implements the ability to shutdown your
1558 current kernel, and to start another kernel. It is like a reboot
1559 but it is independent of the system firmware. And like a reboot
1560 you can start any kernel with it, not just Linux.
1561
1562 The name comes from the similarity to the exec system call.
1563
1564 It is an ongoing process to be certain the hardware in a machine
1565 is properly shutdown, so do not be surprised if this code does not
1566 initially work for you. As of this writing the exact hardware
1567 interface is strongly in flux, so no good recommendation can be
1568 made.
1569
1570 config CRASH_DUMP
1571 bool "kernel crash dumps"
1572 depends on X86_64 || (X86_32 && HIGHMEM)
1573 ---help---
1574 Generate crash dump after being started by kexec.
1575 This should be normally only set in special crash dump kernels
1576 which are loaded in the main kernel with kexec-tools into
1577 a specially reserved region and then later executed after
1578 a crash by kdump/kexec. The crash dump kernel must be compiled
1579 to a memory address not used by the main kernel or BIOS using
1580 PHYSICAL_START, or it must be built as a relocatable image
1581 (CONFIG_RELOCATABLE=y).
1582 For more details see Documentation/kdump/kdump.txt
1583
1584 config KEXEC_JUMP
1585 bool "kexec jump"
1586 depends on KEXEC && HIBERNATION
1587 ---help---
1588 Jump between original kernel and kexeced kernel and invoke
1589 code in physical address mode via KEXEC
1590
1591 config PHYSICAL_START
1592 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1593 default "0x1000000"
1594 ---help---
1595 This gives the physical address where the kernel is loaded.
1596
1597 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1598 bzImage will decompress itself to above physical address and
1599 run from there. Otherwise, bzImage will run from the address where
1600 it has been loaded by the boot loader and will ignore above physical
1601 address.
1602
1603 In normal kdump cases one does not have to set/change this option
1604 as now bzImage can be compiled as a completely relocatable image
1605 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1606 address. This option is mainly useful for the folks who don't want
1607 to use a bzImage for capturing the crash dump and want to use a
1608 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1609 to be specifically compiled to run from a specific memory area
1610 (normally a reserved region) and this option comes handy.
1611
1612 So if you are using bzImage for capturing the crash dump,
1613 leave the value here unchanged to 0x1000000 and set
1614 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1615 for capturing the crash dump change this value to start of
1616 the reserved region. In other words, it can be set based on
1617 the "X" value as specified in the "crashkernel=YM@XM"
1618 command line boot parameter passed to the panic-ed
1619 kernel. Please take a look at Documentation/kdump/kdump.txt
1620 for more details about crash dumps.
1621
1622 Usage of bzImage for capturing the crash dump is recommended as
1623 one does not have to build two kernels. Same kernel can be used
1624 as production kernel and capture kernel. Above option should have
1625 gone away after relocatable bzImage support is introduced. But it
1626 is present because there are users out there who continue to use
1627 vmlinux for dump capture. This option should go away down the
1628 line.
1629
1630 Don't change this unless you know what you are doing.
1631
1632 config RELOCATABLE
1633 bool "Build a relocatable kernel"
1634 default y
1635 ---help---
1636 This builds a kernel image that retains relocation information
1637 so it can be loaded someplace besides the default 1MB.
1638 The relocations tend to make the kernel binary about 10% larger,
1639 but are discarded at runtime.
1640
1641 One use is for the kexec on panic case where the recovery kernel
1642 must live at a different physical address than the primary
1643 kernel.
1644
1645 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1646 it has been loaded at and the compile time physical address
1647 (CONFIG_PHYSICAL_START) is used as the minimum location.
1648
1649 config RANDOMIZE_BASE
1650 bool "Randomize the address of the kernel image"
1651 depends on RELOCATABLE
1652 depends on !HIBERNATION
1653 default n
1654 ---help---
1655 Randomizes the physical and virtual address at which the
1656 kernel image is decompressed, as a security feature that
1657 deters exploit attempts relying on knowledge of the location
1658 of kernel internals.
1659
1660 Entropy is generated using the RDRAND instruction if it is
1661 supported. If RDTSC is supported, it is used as well. If
1662 neither RDRAND nor RDTSC are supported, then randomness is
1663 read from the i8254 timer.
1664
1665 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1666 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1667 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1668 minimum of 2MiB, only 10 bits of entropy is theoretically
1669 possible. At best, due to page table layouts, 64-bit can use
1670 9 bits of entropy and 32-bit uses 8 bits.
1671
1672 If unsure, say N.
1673
1674 config RANDOMIZE_BASE_MAX_OFFSET
1675 hex "Maximum kASLR offset allowed" if EXPERT
1676 depends on RANDOMIZE_BASE
1677 range 0x0 0x20000000 if X86_32
1678 default "0x20000000" if X86_32
1679 range 0x0 0x40000000 if X86_64
1680 default "0x40000000" if X86_64
1681 ---help---
1682 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1683 memory is used to determine the maximal offset in bytes that will
1684 be applied to the kernel when kernel Address Space Layout
1685 Randomization (kASLR) is active. This must be a multiple of
1686 PHYSICAL_ALIGN.
1687
1688 On 32-bit this is limited to 512MiB by page table layouts. The
1689 default is 512MiB.
1690
1691 On 64-bit this is limited by how the kernel fixmap page table is
1692 positioned, so this cannot be larger than 1GiB currently. Without
1693 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1694 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1695 modules area will shrink to compensate, up to the current maximum
1696 1GiB to 1GiB split. The default is 1GiB.
1697
1698 If unsure, leave at the default value.
1699
1700 # Relocation on x86 needs some additional build support
1701 config X86_NEED_RELOCS
1702 def_bool y
1703 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1704
1705 config PHYSICAL_ALIGN
1706 hex "Alignment value to which kernel should be aligned"
1707 default "0x200000"
1708 range 0x2000 0x1000000 if X86_32
1709 range 0x200000 0x1000000 if X86_64
1710 ---help---
1711 This value puts the alignment restrictions on physical address
1712 where kernel is loaded and run from. Kernel is compiled for an
1713 address which meets above alignment restriction.
1714
1715 If bootloader loads the kernel at a non-aligned address and
1716 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1717 address aligned to above value and run from there.
1718
1719 If bootloader loads the kernel at a non-aligned address and
1720 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1721 load address and decompress itself to the address it has been
1722 compiled for and run from there. The address for which kernel is
1723 compiled already meets above alignment restrictions. Hence the
1724 end result is that kernel runs from a physical address meeting
1725 above alignment restrictions.
1726
1727 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1728 this value must be a multiple of 0x200000.
1729
1730 Don't change this unless you know what you are doing.
1731
1732 config HOTPLUG_CPU
1733 bool "Support for hot-pluggable CPUs"
1734 depends on SMP
1735 ---help---
1736 Say Y here to allow turning CPUs off and on. CPUs can be
1737 controlled through /sys/devices/system/cpu.
1738 ( Note: power management support will enable this option
1739 automatically on SMP systems. )
1740 Say N if you want to disable CPU hotplug.
1741
1742 config BOOTPARAM_HOTPLUG_CPU0
1743 bool "Set default setting of cpu0_hotpluggable"
1744 default n
1745 depends on HOTPLUG_CPU
1746 ---help---
1747 Set whether default state of cpu0_hotpluggable is on or off.
1748
1749 Say Y here to enable CPU0 hotplug by default. If this switch
1750 is turned on, there is no need to give cpu0_hotplug kernel
1751 parameter and the CPU0 hotplug feature is enabled by default.
1752
1753 Please note: there are two known CPU0 dependencies if you want
1754 to enable the CPU0 hotplug feature either by this switch or by
1755 cpu0_hotplug kernel parameter.
1756
1757 First, resume from hibernate or suspend always starts from CPU0.
1758 So hibernate and suspend are prevented if CPU0 is offline.
1759
1760 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1761 offline if any interrupt can not migrate out of CPU0. There may
1762 be other CPU0 dependencies.
1763
1764 Please make sure the dependencies are under your control before
1765 you enable this feature.
1766
1767 Say N if you don't want to enable CPU0 hotplug feature by default.
1768 You still can enable the CPU0 hotplug feature at boot by kernel
1769 parameter cpu0_hotplug.
1770
1771 config DEBUG_HOTPLUG_CPU0
1772 def_bool n
1773 prompt "Debug CPU0 hotplug"
1774 depends on HOTPLUG_CPU
1775 ---help---
1776 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1777 soon as possible and boots up userspace with CPU0 offlined. User
1778 can online CPU0 back after boot time.
1779
1780 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1781 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1782 compilation or giving cpu0_hotplug kernel parameter at boot.
1783
1784 If unsure, say N.
1785
1786 config COMPAT_VDSO
1787 def_bool n
1788 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
1789 depends on X86_32 || IA32_EMULATION
1790 ---help---
1791 Certain buggy versions of glibc will crash if they are
1792 presented with a 32-bit vDSO that is not mapped at the address
1793 indicated in its segment table.
1794
1795 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
1796 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
1797 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
1798 the only released version with the bug, but OpenSUSE 9
1799 contains a buggy "glibc 2.3.2".
1800
1801 The symptom of the bug is that everything crashes on startup, saying:
1802 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
1803
1804 Saying Y here changes the default value of the vdso32 boot
1805 option from 1 to 0, which turns off the 32-bit vDSO entirely.
1806 This works around the glibc bug but hurts performance.
1807
1808 If unsure, say N: if you are compiling your own kernel, you
1809 are unlikely to be using a buggy version of glibc.
1810
1811 config CMDLINE_BOOL
1812 bool "Built-in kernel command line"
1813 ---help---
1814 Allow for specifying boot arguments to the kernel at
1815 build time. On some systems (e.g. embedded ones), it is
1816 necessary or convenient to provide some or all of the
1817 kernel boot arguments with the kernel itself (that is,
1818 to not rely on the boot loader to provide them.)
1819
1820 To compile command line arguments into the kernel,
1821 set this option to 'Y', then fill in the
1822 the boot arguments in CONFIG_CMDLINE.
1823
1824 Systems with fully functional boot loaders (i.e. non-embedded)
1825 should leave this option set to 'N'.
1826
1827 config CMDLINE
1828 string "Built-in kernel command string"
1829 depends on CMDLINE_BOOL
1830 default ""
1831 ---help---
1832 Enter arguments here that should be compiled into the kernel
1833 image and used at boot time. If the boot loader provides a
1834 command line at boot time, it is appended to this string to
1835 form the full kernel command line, when the system boots.
1836
1837 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1838 change this behavior.
1839
1840 In most cases, the command line (whether built-in or provided
1841 by the boot loader) should specify the device for the root
1842 file system.
1843
1844 config CMDLINE_OVERRIDE
1845 bool "Built-in command line overrides boot loader arguments"
1846 depends on CMDLINE_BOOL
1847 ---help---
1848 Set this option to 'Y' to have the kernel ignore the boot loader
1849 command line, and use ONLY the built-in command line.
1850
1851 This is used to work around broken boot loaders. This should
1852 be set to 'N' under normal conditions.
1853
1854 endmenu
1855
1856 config ARCH_ENABLE_MEMORY_HOTPLUG
1857 def_bool y
1858 depends on X86_64 || (X86_32 && HIGHMEM)
1859
1860 config ARCH_ENABLE_MEMORY_HOTREMOVE
1861 def_bool y
1862 depends on MEMORY_HOTPLUG
1863
1864 config USE_PERCPU_NUMA_NODE_ID
1865 def_bool y
1866 depends on NUMA
1867
1868 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1869 def_bool y
1870 depends on X86_64 || X86_PAE
1871
1872 menu "Power management and ACPI options"
1873
1874 config ARCH_HIBERNATION_HEADER
1875 def_bool y
1876 depends on X86_64 && HIBERNATION
1877
1878 source "kernel/power/Kconfig"
1879
1880 source "drivers/acpi/Kconfig"
1881
1882 source "drivers/sfi/Kconfig"
1883
1884 config X86_APM_BOOT
1885 def_bool y
1886 depends on APM
1887
1888 menuconfig APM
1889 tristate "APM (Advanced Power Management) BIOS support"
1890 depends on X86_32 && PM_SLEEP
1891 ---help---
1892 APM is a BIOS specification for saving power using several different
1893 techniques. This is mostly useful for battery powered laptops with
1894 APM compliant BIOSes. If you say Y here, the system time will be
1895 reset after a RESUME operation, the /proc/apm device will provide
1896 battery status information, and user-space programs will receive
1897 notification of APM "events" (e.g. battery status change).
1898
1899 If you select "Y" here, you can disable actual use of the APM
1900 BIOS by passing the "apm=off" option to the kernel at boot time.
1901
1902 Note that the APM support is almost completely disabled for
1903 machines with more than one CPU.
1904
1905 In order to use APM, you will need supporting software. For location
1906 and more information, read <file:Documentation/power/apm-acpi.txt>
1907 and the Battery Powered Linux mini-HOWTO, available from
1908 <http://www.tldp.org/docs.html#howto>.
1909
1910 This driver does not spin down disk drives (see the hdparm(8)
1911 manpage ("man 8 hdparm") for that), and it doesn't turn off
1912 VESA-compliant "green" monitors.
1913
1914 This driver does not support the TI 4000M TravelMate and the ACER
1915 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1916 desktop machines also don't have compliant BIOSes, and this driver
1917 may cause those machines to panic during the boot phase.
1918
1919 Generally, if you don't have a battery in your machine, there isn't
1920 much point in using this driver and you should say N. If you get
1921 random kernel OOPSes or reboots that don't seem to be related to
1922 anything, try disabling/enabling this option (or disabling/enabling
1923 APM in your BIOS).
1924
1925 Some other things you should try when experiencing seemingly random,
1926 "weird" problems:
1927
1928 1) make sure that you have enough swap space and that it is
1929 enabled.
1930 2) pass the "no-hlt" option to the kernel
1931 3) switch on floating point emulation in the kernel and pass
1932 the "no387" option to the kernel
1933 4) pass the "floppy=nodma" option to the kernel
1934 5) pass the "mem=4M" option to the kernel (thereby disabling
1935 all but the first 4 MB of RAM)
1936 6) make sure that the CPU is not over clocked.
1937 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1938 8) disable the cache from your BIOS settings
1939 9) install a fan for the video card or exchange video RAM
1940 10) install a better fan for the CPU
1941 11) exchange RAM chips
1942 12) exchange the motherboard.
1943
1944 To compile this driver as a module, choose M here: the
1945 module will be called apm.
1946
1947 if APM
1948
1949 config APM_IGNORE_USER_SUSPEND
1950 bool "Ignore USER SUSPEND"
1951 ---help---
1952 This option will ignore USER SUSPEND requests. On machines with a
1953 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1954 series notebooks, it is necessary to say Y because of a BIOS bug.
1955
1956 config APM_DO_ENABLE
1957 bool "Enable PM at boot time"
1958 ---help---
1959 Enable APM features at boot time. From page 36 of the APM BIOS
1960 specification: "When disabled, the APM BIOS does not automatically
1961 power manage devices, enter the Standby State, enter the Suspend
1962 State, or take power saving steps in response to CPU Idle calls."
1963 This driver will make CPU Idle calls when Linux is idle (unless this
1964 feature is turned off -- see "Do CPU IDLE calls", below). This
1965 should always save battery power, but more complicated APM features
1966 will be dependent on your BIOS implementation. You may need to turn
1967 this option off if your computer hangs at boot time when using APM
1968 support, or if it beeps continuously instead of suspending. Turn
1969 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1970 T400CDT. This is off by default since most machines do fine without
1971 this feature.
1972
1973 config APM_CPU_IDLE
1974 depends on CPU_IDLE
1975 bool "Make CPU Idle calls when idle"
1976 ---help---
1977 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1978 On some machines, this can activate improved power savings, such as
1979 a slowed CPU clock rate, when the machine is idle. These idle calls
1980 are made after the idle loop has run for some length of time (e.g.,
1981 333 mS). On some machines, this will cause a hang at boot time or
1982 whenever the CPU becomes idle. (On machines with more than one CPU,
1983 this option does nothing.)
1984
1985 config APM_DISPLAY_BLANK
1986 bool "Enable console blanking using APM"
1987 ---help---
1988 Enable console blanking using the APM. Some laptops can use this to
1989 turn off the LCD backlight when the screen blanker of the Linux
1990 virtual console blanks the screen. Note that this is only used by
1991 the virtual console screen blanker, and won't turn off the backlight
1992 when using the X Window system. This also doesn't have anything to
1993 do with your VESA-compliant power-saving monitor. Further, this
1994 option doesn't work for all laptops -- it might not turn off your
1995 backlight at all, or it might print a lot of errors to the console,
1996 especially if you are using gpm.
1997
1998 config APM_ALLOW_INTS
1999 bool "Allow interrupts during APM BIOS calls"
2000 ---help---
2001 Normally we disable external interrupts while we are making calls to
2002 the APM BIOS as a measure to lessen the effects of a badly behaving
2003 BIOS implementation. The BIOS should reenable interrupts if it
2004 needs to. Unfortunately, some BIOSes do not -- especially those in
2005 many of the newer IBM Thinkpads. If you experience hangs when you
2006 suspend, try setting this to Y. Otherwise, say N.
2007
2008 endif # APM
2009
2010 source "drivers/cpufreq/Kconfig"
2011
2012 source "drivers/cpuidle/Kconfig"
2013
2014 source "drivers/idle/Kconfig"
2015
2016 endmenu
2017
2018
2019 menu "Bus options (PCI etc.)"
2020
2021 config PCI
2022 bool "PCI support"
2023 default y
2024 ---help---
2025 Find out whether you have a PCI motherboard. PCI is the name of a
2026 bus system, i.e. the way the CPU talks to the other stuff inside
2027 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2028 VESA. If you have PCI, say Y, otherwise N.
2029
2030 choice
2031 prompt "PCI access mode"
2032 depends on X86_32 && PCI
2033 default PCI_GOANY
2034 ---help---
2035 On PCI systems, the BIOS can be used to detect the PCI devices and
2036 determine their configuration. However, some old PCI motherboards
2037 have BIOS bugs and may crash if this is done. Also, some embedded
2038 PCI-based systems don't have any BIOS at all. Linux can also try to
2039 detect the PCI hardware directly without using the BIOS.
2040
2041 With this option, you can specify how Linux should detect the
2042 PCI devices. If you choose "BIOS", the BIOS will be used,
2043 if you choose "Direct", the BIOS won't be used, and if you
2044 choose "MMConfig", then PCI Express MMCONFIG will be used.
2045 If you choose "Any", the kernel will try MMCONFIG, then the
2046 direct access method and falls back to the BIOS if that doesn't
2047 work. If unsure, go with the default, which is "Any".
2048
2049 config PCI_GOBIOS
2050 bool "BIOS"
2051
2052 config PCI_GOMMCONFIG
2053 bool "MMConfig"
2054
2055 config PCI_GODIRECT
2056 bool "Direct"
2057
2058 config PCI_GOOLPC
2059 bool "OLPC XO-1"
2060 depends on OLPC
2061
2062 config PCI_GOANY
2063 bool "Any"
2064
2065 endchoice
2066
2067 config PCI_BIOS
2068 def_bool y
2069 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2070
2071 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2072 config PCI_DIRECT
2073 def_bool y
2074 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2075
2076 config PCI_MMCONFIG
2077 def_bool y
2078 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2079
2080 config PCI_OLPC
2081 def_bool y
2082 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2083
2084 config PCI_XEN
2085 def_bool y
2086 depends on PCI && XEN
2087 select SWIOTLB_XEN
2088
2089 config PCI_DOMAINS
2090 def_bool y
2091 depends on PCI
2092
2093 config PCI_MMCONFIG
2094 bool "Support mmconfig PCI config space access"
2095 depends on X86_64 && PCI && ACPI
2096
2097 config PCI_CNB20LE_QUIRK
2098 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2099 depends on PCI
2100 help
2101 Read the PCI windows out of the CNB20LE host bridge. This allows
2102 PCI hotplug to work on systems with the CNB20LE chipset which do
2103 not have ACPI.
2104
2105 There's no public spec for this chipset, and this functionality
2106 is known to be incomplete.
2107
2108 You should say N unless you know you need this.
2109
2110 source "drivers/pci/pcie/Kconfig"
2111
2112 source "drivers/pci/Kconfig"
2113
2114 # x86_64 have no ISA slots, but can have ISA-style DMA.
2115 config ISA_DMA_API
2116 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2117 default y
2118 help
2119 Enables ISA-style DMA support for devices requiring such controllers.
2120 If unsure, say Y.
2121
2122 if X86_32
2123
2124 config ISA
2125 bool "ISA support"
2126 ---help---
2127 Find out whether you have ISA slots on your motherboard. ISA is the
2128 name of a bus system, i.e. the way the CPU talks to the other stuff
2129 inside your box. Other bus systems are PCI, EISA, MicroChannel
2130 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2131 newer boards don't support it. If you have ISA, say Y, otherwise N.
2132
2133 config EISA
2134 bool "EISA support"
2135 depends on ISA
2136 ---help---
2137 The Extended Industry Standard Architecture (EISA) bus was
2138 developed as an open alternative to the IBM MicroChannel bus.
2139
2140 The EISA bus provided some of the features of the IBM MicroChannel
2141 bus while maintaining backward compatibility with cards made for
2142 the older ISA bus. The EISA bus saw limited use between 1988 and
2143 1995 when it was made obsolete by the PCI bus.
2144
2145 Say Y here if you are building a kernel for an EISA-based machine.
2146
2147 Otherwise, say N.
2148
2149 source "drivers/eisa/Kconfig"
2150
2151 config SCx200
2152 tristate "NatSemi SCx200 support"
2153 ---help---
2154 This provides basic support for National Semiconductor's
2155 (now AMD's) Geode processors. The driver probes for the
2156 PCI-IDs of several on-chip devices, so its a good dependency
2157 for other scx200_* drivers.
2158
2159 If compiled as a module, the driver is named scx200.
2160
2161 config SCx200HR_TIMER
2162 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2163 depends on SCx200
2164 default y
2165 ---help---
2166 This driver provides a clocksource built upon the on-chip
2167 27MHz high-resolution timer. Its also a workaround for
2168 NSC Geode SC-1100's buggy TSC, which loses time when the
2169 processor goes idle (as is done by the scheduler). The
2170 other workaround is idle=poll boot option.
2171
2172 config OLPC
2173 bool "One Laptop Per Child support"
2174 depends on !X86_PAE
2175 select GPIOLIB
2176 select OF
2177 select OF_PROMTREE
2178 select IRQ_DOMAIN
2179 ---help---
2180 Add support for detecting the unique features of the OLPC
2181 XO hardware.
2182
2183 config OLPC_XO1_PM
2184 bool "OLPC XO-1 Power Management"
2185 depends on OLPC && MFD_CS5535 && PM_SLEEP
2186 select MFD_CORE
2187 ---help---
2188 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2189
2190 config OLPC_XO1_RTC
2191 bool "OLPC XO-1 Real Time Clock"
2192 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2193 ---help---
2194 Add support for the XO-1 real time clock, which can be used as a
2195 programmable wakeup source.
2196
2197 config OLPC_XO1_SCI
2198 bool "OLPC XO-1 SCI extras"
2199 depends on OLPC && OLPC_XO1_PM
2200 depends on INPUT=y
2201 select POWER_SUPPLY
2202 select GPIO_CS5535
2203 select MFD_CORE
2204 ---help---
2205 Add support for SCI-based features of the OLPC XO-1 laptop:
2206 - EC-driven system wakeups
2207 - Power button
2208 - Ebook switch
2209 - Lid switch
2210 - AC adapter status updates
2211 - Battery status updates
2212
2213 config OLPC_XO15_SCI
2214 bool "OLPC XO-1.5 SCI extras"
2215 depends on OLPC && ACPI
2216 select POWER_SUPPLY
2217 ---help---
2218 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2219 - EC-driven system wakeups
2220 - AC adapter status updates
2221 - Battery status updates
2222
2223 config ALIX
2224 bool "PCEngines ALIX System Support (LED setup)"
2225 select GPIOLIB
2226 ---help---
2227 This option enables system support for the PCEngines ALIX.
2228 At present this just sets up LEDs for GPIO control on
2229 ALIX2/3/6 boards. However, other system specific setup should
2230 get added here.
2231
2232 Note: You must still enable the drivers for GPIO and LED support
2233 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2234
2235 Note: You have to set alix.force=1 for boards with Award BIOS.
2236
2237 config NET5501
2238 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2239 select GPIOLIB
2240 ---help---
2241 This option enables system support for the Soekris Engineering net5501.
2242
2243 config GEOS
2244 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2245 select GPIOLIB
2246 depends on DMI
2247 ---help---
2248 This option enables system support for the Traverse Technologies GEOS.
2249
2250 config TS5500
2251 bool "Technologic Systems TS-5500 platform support"
2252 depends on MELAN
2253 select CHECK_SIGNATURE
2254 select NEW_LEDS
2255 select LEDS_CLASS
2256 ---help---
2257 This option enables system support for the Technologic Systems TS-5500.
2258
2259 endif # X86_32
2260
2261 config AMD_NB
2262 def_bool y
2263 depends on CPU_SUP_AMD && PCI
2264
2265 source "drivers/pcmcia/Kconfig"
2266
2267 source "drivers/pci/hotplug/Kconfig"
2268
2269 config RAPIDIO
2270 tristate "RapidIO support"
2271 depends on PCI
2272 default n
2273 help
2274 If enabled this option will include drivers and the core
2275 infrastructure code to support RapidIO interconnect devices.
2276
2277 source "drivers/rapidio/Kconfig"
2278
2279 config X86_SYSFB
2280 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2281 help
2282 Firmwares often provide initial graphics framebuffers so the BIOS,
2283 bootloader or kernel can show basic video-output during boot for
2284 user-guidance and debugging. Historically, x86 used the VESA BIOS
2285 Extensions and EFI-framebuffers for this, which are mostly limited
2286 to x86.
2287 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2288 framebuffers so the new generic system-framebuffer drivers can be
2289 used on x86. If the framebuffer is not compatible with the generic
2290 modes, it is adverticed as fallback platform framebuffer so legacy
2291 drivers like efifb, vesafb and uvesafb can pick it up.
2292 If this option is not selected, all system framebuffers are always
2293 marked as fallback platform framebuffers as usual.
2294
2295 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2296 not be able to pick up generic system framebuffers if this option
2297 is selected. You are highly encouraged to enable simplefb as
2298 replacement if you select this option. simplefb can correctly deal
2299 with generic system framebuffers. But you should still keep vesafb
2300 and others enabled as fallback if a system framebuffer is
2301 incompatible with simplefb.
2302
2303 If unsure, say Y.
2304
2305 endmenu
2306
2307
2308 menu "Executable file formats / Emulations"
2309
2310 source "fs/Kconfig.binfmt"
2311
2312 config IA32_EMULATION
2313 bool "IA32 Emulation"
2314 depends on X86_64
2315 select BINFMT_ELF
2316 select COMPAT_BINFMT_ELF
2317 select HAVE_UID16
2318 ---help---
2319 Include code to run legacy 32-bit programs under a
2320 64-bit kernel. You should likely turn this on, unless you're
2321 100% sure that you don't have any 32-bit programs left.
2322
2323 config IA32_AOUT
2324 tristate "IA32 a.out support"
2325 depends on IA32_EMULATION
2326 ---help---
2327 Support old a.out binaries in the 32bit emulation.
2328
2329 config X86_X32
2330 bool "x32 ABI for 64-bit mode"
2331 depends on X86_64 && IA32_EMULATION
2332 ---help---
2333 Include code to run binaries for the x32 native 32-bit ABI
2334 for 64-bit processors. An x32 process gets access to the
2335 full 64-bit register file and wide data path while leaving
2336 pointers at 32 bits for smaller memory footprint.
2337
2338 You will need a recent binutils (2.22 or later) with
2339 elf32_x86_64 support enabled to compile a kernel with this
2340 option set.
2341
2342 config COMPAT
2343 def_bool y
2344 depends on IA32_EMULATION || X86_X32
2345 select ARCH_WANT_OLD_COMPAT_IPC
2346
2347 if COMPAT
2348 config COMPAT_FOR_U64_ALIGNMENT
2349 def_bool y
2350
2351 config SYSVIPC_COMPAT
2352 def_bool y
2353 depends on SYSVIPC
2354
2355 config KEYS_COMPAT
2356 def_bool y
2357 depends on KEYS
2358 endif
2359
2360 endmenu
2361
2362
2363 config HAVE_ATOMIC_IOMAP
2364 def_bool y
2365 depends on X86_32
2366
2367 config X86_DEV_DMA_OPS
2368 bool
2369 depends on X86_64 || STA2X11
2370
2371 config X86_DMA_REMAP
2372 bool
2373 depends on STA2X11
2374
2375 config IOSF_MBI
2376 bool
2377 depends on PCI
2378 ---help---
2379 To be selected by modules requiring access to the Intel OnChip System
2380 Fabric (IOSF) Sideband MailBox Interface (MBI). For MBI platforms
2381 enumerable by PCI.
2382
2383 source "net/Kconfig"
2384
2385 source "drivers/Kconfig"
2386
2387 source "drivers/firmware/Kconfig"
2388
2389 source "fs/Kconfig"
2390
2391 source "arch/x86/Kconfig.debug"
2392
2393 source "security/Kconfig"
2394
2395 source "crypto/Kconfig"
2396
2397 source "arch/x86/kvm/Kconfig"
2398
2399 source "lib/Kconfig"
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