sched/x86: Make CONFIG_SCHED_MC_PRIO=y easier to enable
[GitHub/moto-9609/android_kernel_motorola_exynos9610.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_DEVMEM_IS_ALLOWED
27 select ARCH_HAS_ELF_RANDOMIZE
28 select ARCH_HAS_FAST_MULTIPLIER
29 select ARCH_HAS_GCOV_PROFILE_ALL
30 select ARCH_HAS_GIGANTIC_PAGE if X86_64
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_ARCH_VMAP_STACK if X86_64
97 select HAVE_CC_STACKPROTECTOR
98 select HAVE_CMPXCHG_DOUBLE
99 select HAVE_CMPXCHG_LOCAL
100 select HAVE_CONTEXT_TRACKING if X86_64
101 select HAVE_COPY_THREAD_TLS
102 select HAVE_C_RECORDMCOUNT
103 select HAVE_DEBUG_KMEMLEAK
104 select HAVE_DEBUG_STACKOVERFLOW
105 select HAVE_DMA_API_DEBUG
106 select HAVE_DMA_CONTIGUOUS
107 select HAVE_DYNAMIC_FTRACE
108 select HAVE_DYNAMIC_FTRACE_WITH_REGS
109 select HAVE_EFFICIENT_UNALIGNED_ACCESS
110 select HAVE_EXIT_THREAD
111 select HAVE_FENTRY if X86_64
112 select HAVE_FTRACE_MCOUNT_RECORD
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 THREAD_INFO_IN_TASK
161 select USER_STACKTRACE_SUPPORT
162 select VIRT_TO_BUS
163 select X86_DEV_DMA_OPS if X86_64
164 select X86_FEATURE_NAMES if PROC_FS
165 select HAVE_STACK_VALIDATION if X86_64
166 select ARCH_USES_HIGH_VMA_FLAGS if X86_INTEL_MEMORY_PROTECTION_KEYS
167 select ARCH_HAS_PKEYS if X86_INTEL_MEMORY_PROTECTION_KEYS
168
169 config INSTRUCTION_DECODER
170 def_bool y
171 depends on KPROBES || PERF_EVENTS || UPROBES
172
173 config OUTPUT_FORMAT
174 string
175 default "elf32-i386" if X86_32
176 default "elf64-x86-64" if X86_64
177
178 config ARCH_DEFCONFIG
179 string
180 default "arch/x86/configs/i386_defconfig" if X86_32
181 default "arch/x86/configs/x86_64_defconfig" if X86_64
182
183 config LOCKDEP_SUPPORT
184 def_bool y
185
186 config STACKTRACE_SUPPORT
187 def_bool y
188
189 config MMU
190 def_bool y
191
192 config ARCH_MMAP_RND_BITS_MIN
193 default 28 if 64BIT
194 default 8
195
196 config ARCH_MMAP_RND_BITS_MAX
197 default 32 if 64BIT
198 default 16
199
200 config ARCH_MMAP_RND_COMPAT_BITS_MIN
201 default 8
202
203 config ARCH_MMAP_RND_COMPAT_BITS_MAX
204 default 16
205
206 config SBUS
207 bool
208
209 config NEED_DMA_MAP_STATE
210 def_bool y
211 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
212
213 config NEED_SG_DMA_LENGTH
214 def_bool y
215
216 config GENERIC_ISA_DMA
217 def_bool y
218 depends on ISA_DMA_API
219
220 config GENERIC_BUG
221 def_bool y
222 depends on BUG
223 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
224
225 config GENERIC_BUG_RELATIVE_POINTERS
226 bool
227
228 config GENERIC_HWEIGHT
229 def_bool y
230
231 config ARCH_MAY_HAVE_PC_FDC
232 def_bool y
233 depends on ISA_DMA_API
234
235 config RWSEM_XCHGADD_ALGORITHM
236 def_bool y
237
238 config GENERIC_CALIBRATE_DELAY
239 def_bool y
240
241 config ARCH_HAS_CPU_RELAX
242 def_bool y
243
244 config ARCH_HAS_CACHE_LINE_SIZE
245 def_bool y
246
247 config HAVE_SETUP_PER_CPU_AREA
248 def_bool y
249
250 config NEED_PER_CPU_EMBED_FIRST_CHUNK
251 def_bool y
252
253 config NEED_PER_CPU_PAGE_FIRST_CHUNK
254 def_bool y
255
256 config ARCH_HIBERNATION_POSSIBLE
257 def_bool y
258
259 config ARCH_SUSPEND_POSSIBLE
260 def_bool y
261
262 config ARCH_WANT_HUGE_PMD_SHARE
263 def_bool y
264
265 config ARCH_WANT_GENERAL_HUGETLB
266 def_bool y
267
268 config ZONE_DMA32
269 def_bool y if X86_64
270
271 config AUDIT_ARCH
272 def_bool y if X86_64
273
274 config ARCH_SUPPORTS_OPTIMIZED_INLINING
275 def_bool y
276
277 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
278 def_bool y
279
280 config KASAN_SHADOW_OFFSET
281 hex
282 depends on KASAN
283 default 0xdffffc0000000000
284
285 config HAVE_INTEL_TXT
286 def_bool y
287 depends on INTEL_IOMMU && ACPI
288
289 config X86_32_SMP
290 def_bool y
291 depends on X86_32 && SMP
292
293 config X86_64_SMP
294 def_bool y
295 depends on X86_64 && SMP
296
297 config X86_32_LAZY_GS
298 def_bool y
299 depends on X86_32 && !CC_STACKPROTECTOR
300
301 config ARCH_SUPPORTS_UPROBES
302 def_bool y
303
304 config FIX_EARLYCON_MEM
305 def_bool y
306
307 config DEBUG_RODATA
308 def_bool y
309
310 config PGTABLE_LEVELS
311 int
312 default 4 if X86_64
313 default 3 if X86_PAE
314 default 2
315
316 source "init/Kconfig"
317 source "kernel/Kconfig.freezer"
318
319 menu "Processor type and features"
320
321 config ZONE_DMA
322 bool "DMA memory allocation support" if EXPERT
323 default y
324 help
325 DMA memory allocation support allows devices with less than 32-bit
326 addressing to allocate within the first 16MB of address space.
327 Disable if no such devices will be used.
328
329 If unsure, say Y.
330
331 config SMP
332 bool "Symmetric multi-processing support"
333 ---help---
334 This enables support for systems with more than one CPU. If you have
335 a system with only one CPU, say N. If you have a system with more
336 than one CPU, say Y.
337
338 If you say N here, the kernel will run on uni- and multiprocessor
339 machines, but will use only one CPU of a multiprocessor machine. If
340 you say Y here, the kernel will run on many, but not all,
341 uniprocessor machines. On a uniprocessor machine, the kernel
342 will run faster if you say N here.
343
344 Note that if you say Y here and choose architecture "586" or
345 "Pentium" under "Processor family", the kernel will not work on 486
346 architectures. Similarly, multiprocessor kernels for the "PPro"
347 architecture may not work on all Pentium based boards.
348
349 People using multiprocessor machines who say Y here should also say
350 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
351 Management" code will be disabled if you say Y here.
352
353 See also <file:Documentation/x86/i386/IO-APIC.txt>,
354 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
355 <http://www.tldp.org/docs.html#howto>.
356
357 If you don't know what to do here, say N.
358
359 config X86_FEATURE_NAMES
360 bool "Processor feature human-readable names" if EMBEDDED
361 default y
362 ---help---
363 This option compiles in a table of x86 feature bits and corresponding
364 names. This is required to support /proc/cpuinfo and a few kernel
365 messages. You can disable this to save space, at the expense of
366 making those few kernel messages show numeric feature bits instead.
367
368 If in doubt, say Y.
369
370 config X86_FAST_FEATURE_TESTS
371 bool "Fast CPU feature tests" if EMBEDDED
372 default y
373 ---help---
374 Some fast-paths in the kernel depend on the capabilities of the CPU.
375 Say Y here for the kernel to patch in the appropriate code at runtime
376 based on the capabilities of the CPU. The infrastructure for patching
377 code at runtime takes up some additional space; space-constrained
378 embedded systems may wish to say N here to produce smaller, slightly
379 slower code.
380
381 config X86_X2APIC
382 bool "Support x2apic"
383 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
384 ---help---
385 This enables x2apic support on CPUs that have this feature.
386
387 This allows 32-bit apic IDs (so it can support very large systems),
388 and accesses the local apic via MSRs not via mmio.
389
390 If you don't know what to do here, say N.
391
392 config X86_MPPARSE
393 bool "Enable MPS table" if ACPI || SFI
394 default y
395 depends on X86_LOCAL_APIC
396 ---help---
397 For old smp systems that do not have proper acpi support. Newer systems
398 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
399
400 config X86_BIGSMP
401 bool "Support for big SMP systems with more than 8 CPUs"
402 depends on X86_32 && SMP
403 ---help---
404 This option is needed for the systems that have more than 8 CPUs
405
406 config GOLDFISH
407 def_bool y
408 depends on X86_GOLDFISH
409
410 if X86_32
411 config X86_EXTENDED_PLATFORM
412 bool "Support for extended (non-PC) x86 platforms"
413 default y
414 ---help---
415 If you disable this option then the kernel will only support
416 standard PC platforms. (which covers the vast majority of
417 systems out there.)
418
419 If you enable this option then you'll be able to select support
420 for the following (non-PC) 32 bit x86 platforms:
421 Goldfish (Android emulator)
422 AMD Elan
423 RDC R-321x SoC
424 SGI 320/540 (Visual Workstation)
425 STA2X11-based (e.g. Northville)
426 Moorestown MID devices
427
428 If you have one of these systems, or if you want to build a
429 generic distribution kernel, say Y here - otherwise say N.
430 endif
431
432 if X86_64
433 config X86_EXTENDED_PLATFORM
434 bool "Support for extended (non-PC) x86 platforms"
435 default y
436 ---help---
437 If you disable this option then the kernel will only support
438 standard PC platforms. (which covers the vast majority of
439 systems out there.)
440
441 If you enable this option then you'll be able to select support
442 for the following (non-PC) 64 bit x86 platforms:
443 Numascale NumaChip
444 ScaleMP vSMP
445 SGI Ultraviolet
446
447 If you have one of these systems, or if you want to build a
448 generic distribution kernel, say Y here - otherwise say N.
449 endif
450 # This is an alphabetically sorted list of 64 bit extended platforms
451 # Please maintain the alphabetic order if and when there are additions
452 config X86_NUMACHIP
453 bool "Numascale NumaChip"
454 depends on X86_64
455 depends on X86_EXTENDED_PLATFORM
456 depends on NUMA
457 depends on SMP
458 depends on X86_X2APIC
459 depends on PCI_MMCONFIG
460 ---help---
461 Adds support for Numascale NumaChip large-SMP systems. Needed to
462 enable more than ~168 cores.
463 If you don't have one of these, you should say N here.
464
465 config X86_VSMP
466 bool "ScaleMP vSMP"
467 select HYPERVISOR_GUEST
468 select PARAVIRT
469 depends on X86_64 && PCI
470 depends on X86_EXTENDED_PLATFORM
471 depends on SMP
472 ---help---
473 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
474 supposed to run on these EM64T-based machines. Only choose this option
475 if you have one of these machines.
476
477 config X86_UV
478 bool "SGI Ultraviolet"
479 depends on X86_64
480 depends on X86_EXTENDED_PLATFORM
481 depends on NUMA
482 depends on EFI
483 depends on X86_X2APIC
484 depends on PCI
485 ---help---
486 This option is needed in order to support SGI Ultraviolet systems.
487 If you don't have one of these, you should say N here.
488
489 # Following is an alphabetically sorted list of 32 bit extended platforms
490 # Please maintain the alphabetic order if and when there are additions
491
492 config X86_GOLDFISH
493 bool "Goldfish (Virtual Platform)"
494 depends on X86_EXTENDED_PLATFORM
495 ---help---
496 Enable support for the Goldfish virtual platform used primarily
497 for Android development. Unless you are building for the Android
498 Goldfish emulator say N here.
499
500 config X86_INTEL_CE
501 bool "CE4100 TV platform"
502 depends on PCI
503 depends on PCI_GODIRECT
504 depends on X86_IO_APIC
505 depends on X86_32
506 depends on X86_EXTENDED_PLATFORM
507 select X86_REBOOTFIXUPS
508 select OF
509 select OF_EARLY_FLATTREE
510 ---help---
511 Select for the Intel CE media processor (CE4100) SOC.
512 This option compiles in support for the CE4100 SOC for settop
513 boxes and media devices.
514
515 config X86_INTEL_MID
516 bool "Intel MID platform support"
517 depends on X86_EXTENDED_PLATFORM
518 depends on X86_PLATFORM_DEVICES
519 depends on PCI
520 depends on X86_64 || (PCI_GOANY && X86_32)
521 depends on X86_IO_APIC
522 select SFI
523 select I2C
524 select DW_APB_TIMER
525 select APB_TIMER
526 select INTEL_SCU_IPC
527 select MFD_INTEL_MSIC
528 ---help---
529 Select to build a kernel capable of supporting Intel MID (Mobile
530 Internet Device) platform systems which do not have the PCI legacy
531 interfaces. If you are building for a PC class system say N here.
532
533 Intel MID platforms are based on an Intel processor and chipset which
534 consume less power than most of the x86 derivatives.
535
536 config X86_INTEL_QUARK
537 bool "Intel Quark platform support"
538 depends on X86_32
539 depends on X86_EXTENDED_PLATFORM
540 depends on X86_PLATFORM_DEVICES
541 depends on X86_TSC
542 depends on PCI
543 depends on PCI_GOANY
544 depends on X86_IO_APIC
545 select IOSF_MBI
546 select INTEL_IMR
547 select COMMON_CLK
548 ---help---
549 Select to include support for Quark X1000 SoC.
550 Say Y here if you have a Quark based system such as the Arduino
551 compatible Intel Galileo.
552
553 config MLX_PLATFORM
554 tristate "Mellanox Technologies platform support"
555 depends on X86_64
556 depends on X86_EXTENDED_PLATFORM
557 ---help---
558 This option enables system support for the Mellanox Technologies
559 platform.
560
561 Say Y here if you are building a kernel for Mellanox system.
562
563 Otherwise, say N.
564
565 config X86_INTEL_LPSS
566 bool "Intel Low Power Subsystem Support"
567 depends on X86 && ACPI
568 select COMMON_CLK
569 select PINCTRL
570 select IOSF_MBI
571 ---help---
572 Select to build support for Intel Low Power Subsystem such as
573 found on Intel Lynxpoint PCH. Selecting this option enables
574 things like clock tree (common clock framework) and pincontrol
575 which are needed by the LPSS peripheral drivers.
576
577 config X86_AMD_PLATFORM_DEVICE
578 bool "AMD ACPI2Platform devices support"
579 depends on ACPI
580 select COMMON_CLK
581 select PINCTRL
582 ---help---
583 Select to interpret AMD specific ACPI device to platform device
584 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
585 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
586 implemented under PINCTRL subsystem.
587
588 config IOSF_MBI
589 tristate "Intel SoC IOSF Sideband support for SoC platforms"
590 depends on PCI
591 ---help---
592 This option enables sideband register access support for Intel SoC
593 platforms. On these platforms the IOSF sideband is used in lieu of
594 MSR's for some register accesses, mostly but not limited to thermal
595 and power. Drivers may query the availability of this device to
596 determine if they need the sideband in order to work on these
597 platforms. The sideband is available on the following SoC products.
598 This list is not meant to be exclusive.
599 - BayTrail
600 - Braswell
601 - Quark
602
603 You should say Y if you are running a kernel on one of these SoC's.
604
605 config IOSF_MBI_DEBUG
606 bool "Enable IOSF sideband access through debugfs"
607 depends on IOSF_MBI && DEBUG_FS
608 ---help---
609 Select this option to expose the IOSF sideband access registers (MCR,
610 MDR, MCRX) through debugfs to write and read register information from
611 different units on the SoC. This is most useful for obtaining device
612 state information for debug and analysis. As this is a general access
613 mechanism, users of this option would have specific knowledge of the
614 device they want to access.
615
616 If you don't require the option or are in doubt, say N.
617
618 config X86_RDC321X
619 bool "RDC R-321x SoC"
620 depends on X86_32
621 depends on X86_EXTENDED_PLATFORM
622 select M486
623 select X86_REBOOTFIXUPS
624 ---help---
625 This option is needed for RDC R-321x system-on-chip, also known
626 as R-8610-(G).
627 If you don't have one of these chips, you should say N here.
628
629 config X86_32_NON_STANDARD
630 bool "Support non-standard 32-bit SMP architectures"
631 depends on X86_32 && SMP
632 depends on X86_EXTENDED_PLATFORM
633 ---help---
634 This option compiles in the bigsmp and STA2X11 default
635 subarchitectures. It is intended for a generic binary
636 kernel. If you select them all, kernel will probe it one by
637 one and will fallback to default.
638
639 # Alphabetically sorted list of Non standard 32 bit platforms
640
641 config X86_SUPPORTS_MEMORY_FAILURE
642 def_bool y
643 # MCE code calls memory_failure():
644 depends on X86_MCE
645 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
646 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
647 depends on X86_64 || !SPARSEMEM
648 select ARCH_SUPPORTS_MEMORY_FAILURE
649
650 config STA2X11
651 bool "STA2X11 Companion Chip Support"
652 depends on X86_32_NON_STANDARD && PCI
653 select X86_DEV_DMA_OPS
654 select X86_DMA_REMAP
655 select SWIOTLB
656 select MFD_STA2X11
657 select GPIOLIB
658 default n
659 ---help---
660 This adds support for boards based on the STA2X11 IO-Hub,
661 a.k.a. "ConneXt". The chip is used in place of the standard
662 PC chipset, so all "standard" peripherals are missing. If this
663 option is selected the kernel will still be able to boot on
664 standard PC machines.
665
666 config X86_32_IRIS
667 tristate "Eurobraille/Iris poweroff module"
668 depends on X86_32
669 ---help---
670 The Iris machines from EuroBraille do not have APM or ACPI support
671 to shut themselves down properly. A special I/O sequence is
672 needed to do so, which is what this module does at
673 kernel shutdown.
674
675 This is only for Iris machines from EuroBraille.
676
677 If unused, say N.
678
679 config SCHED_OMIT_FRAME_POINTER
680 def_bool y
681 prompt "Single-depth WCHAN output"
682 depends on X86
683 ---help---
684 Calculate simpler /proc/<PID>/wchan values. If this option
685 is disabled then wchan values will recurse back to the
686 caller function. This provides more accurate wchan values,
687 at the expense of slightly more scheduling overhead.
688
689 If in doubt, say "Y".
690
691 menuconfig HYPERVISOR_GUEST
692 bool "Linux guest support"
693 ---help---
694 Say Y here to enable options for running Linux under various hyper-
695 visors. This option enables basic hypervisor detection and platform
696 setup.
697
698 If you say N, all options in this submenu will be skipped and
699 disabled, and Linux guest support won't be built in.
700
701 if HYPERVISOR_GUEST
702
703 config PARAVIRT
704 bool "Enable paravirtualization code"
705 ---help---
706 This changes the kernel so it can modify itself when it is run
707 under a hypervisor, potentially improving performance significantly
708 over full virtualization. However, when run without a hypervisor
709 the kernel is theoretically slower and slightly larger.
710
711 config PARAVIRT_DEBUG
712 bool "paravirt-ops debugging"
713 depends on PARAVIRT && DEBUG_KERNEL
714 ---help---
715 Enable to debug paravirt_ops internals. Specifically, BUG if
716 a paravirt_op is missing when it is called.
717
718 config PARAVIRT_SPINLOCKS
719 bool "Paravirtualization layer for spinlocks"
720 depends on PARAVIRT && SMP
721 ---help---
722 Paravirtualized spinlocks allow a pvops backend to replace the
723 spinlock implementation with something virtualization-friendly
724 (for example, block the virtual CPU rather than spinning).
725
726 It has a minimal impact on native kernels and gives a nice performance
727 benefit on paravirtualized KVM / Xen kernels.
728
729 If you are unsure how to answer this question, answer Y.
730
731 config QUEUED_LOCK_STAT
732 bool "Paravirt queued spinlock statistics"
733 depends on PARAVIRT_SPINLOCKS && DEBUG_FS
734 ---help---
735 Enable the collection of statistical data on the slowpath
736 behavior of paravirtualized queued spinlocks and report
737 them on debugfs.
738
739 source "arch/x86/xen/Kconfig"
740
741 config KVM_GUEST
742 bool "KVM Guest support (including kvmclock)"
743 depends on PARAVIRT
744 select PARAVIRT_CLOCK
745 default y
746 ---help---
747 This option enables various optimizations for running under the KVM
748 hypervisor. It includes a paravirtualized clock, so that instead
749 of relying on a PIT (or probably other) emulation by the
750 underlying device model, the host provides the guest with
751 timing infrastructure such as time of day, and system time
752
753 config KVM_DEBUG_FS
754 bool "Enable debug information for KVM Guests in debugfs"
755 depends on KVM_GUEST && DEBUG_FS
756 default n
757 ---help---
758 This option enables collection of various statistics for KVM guest.
759 Statistics are displayed in debugfs filesystem. Enabling this option
760 may incur significant overhead.
761
762 source "arch/x86/lguest/Kconfig"
763
764 config PARAVIRT_TIME_ACCOUNTING
765 bool "Paravirtual steal time accounting"
766 depends on PARAVIRT
767 default n
768 ---help---
769 Select this option to enable fine granularity task steal time
770 accounting. Time spent executing other tasks in parallel with
771 the current vCPU is discounted from the vCPU power. To account for
772 that, there can be a small performance impact.
773
774 If in doubt, say N here.
775
776 config PARAVIRT_CLOCK
777 bool
778
779 endif #HYPERVISOR_GUEST
780
781 config NO_BOOTMEM
782 def_bool y
783
784 source "arch/x86/Kconfig.cpu"
785
786 config HPET_TIMER
787 def_bool X86_64
788 prompt "HPET Timer Support" if X86_32
789 ---help---
790 Use the IA-PC HPET (High Precision Event Timer) to manage
791 time in preference to the PIT and RTC, if a HPET is
792 present.
793 HPET is the next generation timer replacing legacy 8254s.
794 The HPET provides a stable time base on SMP
795 systems, unlike the TSC, but it is more expensive to access,
796 as it is off-chip. The interface used is documented
797 in the HPET spec, revision 1.
798
799 You can safely choose Y here. However, HPET will only be
800 activated if the platform and the BIOS support this feature.
801 Otherwise the 8254 will be used for timing services.
802
803 Choose N to continue using the legacy 8254 timer.
804
805 config HPET_EMULATE_RTC
806 def_bool y
807 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
808
809 config APB_TIMER
810 def_bool y if X86_INTEL_MID
811 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
812 select DW_APB_TIMER
813 depends on X86_INTEL_MID && SFI
814 help
815 APB timer is the replacement for 8254, HPET on X86 MID platforms.
816 The APBT provides a stable time base on SMP
817 systems, unlike the TSC, but it is more expensive to access,
818 as it is off-chip. APB timers are always running regardless of CPU
819 C states, they are used as per CPU clockevent device when possible.
820
821 # Mark as expert because too many people got it wrong.
822 # The code disables itself when not needed.
823 config DMI
824 default y
825 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
826 bool "Enable DMI scanning" if EXPERT
827 ---help---
828 Enabled scanning of DMI to identify machine quirks. Say Y
829 here unless you have verified that your setup is not
830 affected by entries in the DMI blacklist. Required by PNP
831 BIOS code.
832
833 config GART_IOMMU
834 bool "Old AMD GART IOMMU support"
835 select SWIOTLB
836 depends on X86_64 && PCI && AMD_NB
837 ---help---
838 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
839 GART based hardware IOMMUs.
840
841 The GART supports full DMA access for devices with 32-bit access
842 limitations, on systems with more than 3 GB. This is usually needed
843 for USB, sound, many IDE/SATA chipsets and some other devices.
844
845 Newer systems typically have a modern AMD IOMMU, supported via
846 the CONFIG_AMD_IOMMU=y config option.
847
848 In normal configurations this driver is only active when needed:
849 there's more than 3 GB of memory and the system contains a
850 32-bit limited device.
851
852 If unsure, say Y.
853
854 config CALGARY_IOMMU
855 bool "IBM Calgary IOMMU support"
856 select SWIOTLB
857 depends on X86_64 && PCI
858 ---help---
859 Support for hardware IOMMUs in IBM's xSeries x366 and x460
860 systems. Needed to run systems with more than 3GB of memory
861 properly with 32-bit PCI devices that do not support DAC
862 (Double Address Cycle). Calgary also supports bus level
863 isolation, where all DMAs pass through the IOMMU. This
864 prevents them from going anywhere except their intended
865 destination. This catches hard-to-find kernel bugs and
866 mis-behaving drivers and devices that do not use the DMA-API
867 properly to set up their DMA buffers. The IOMMU can be
868 turned off at boot time with the iommu=off parameter.
869 Normally the kernel will make the right choice by itself.
870 If unsure, say Y.
871
872 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
873 def_bool y
874 prompt "Should Calgary be enabled by default?"
875 depends on CALGARY_IOMMU
876 ---help---
877 Should Calgary be enabled by default? if you choose 'y', Calgary
878 will be used (if it exists). If you choose 'n', Calgary will not be
879 used even if it exists. If you choose 'n' and would like to use
880 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
881 If unsure, say Y.
882
883 # need this always selected by IOMMU for the VIA workaround
884 config SWIOTLB
885 def_bool y if X86_64
886 ---help---
887 Support for software bounce buffers used on x86-64 systems
888 which don't have a hardware IOMMU. Using this PCI devices
889 which can only access 32-bits of memory can be used on systems
890 with more than 3 GB of memory.
891 If unsure, say Y.
892
893 config IOMMU_HELPER
894 def_bool y
895 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
896
897 config MAXSMP
898 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
899 depends on X86_64 && SMP && DEBUG_KERNEL
900 select CPUMASK_OFFSTACK
901 ---help---
902 Enable maximum number of CPUS and NUMA Nodes for this architecture.
903 If unsure, say N.
904
905 config NR_CPUS
906 int "Maximum number of CPUs" if SMP && !MAXSMP
907 range 2 8 if SMP && X86_32 && !X86_BIGSMP
908 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
909 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
910 default "1" if !SMP
911 default "8192" if MAXSMP
912 default "32" if SMP && X86_BIGSMP
913 default "8" if SMP && X86_32
914 default "64" if SMP
915 ---help---
916 This allows you to specify the maximum number of CPUs which this
917 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
918 supported value is 8192, otherwise the maximum value is 512. The
919 minimum value which makes sense is 2.
920
921 This is purely to save memory - each supported CPU adds
922 approximately eight kilobytes to the kernel image.
923
924 config SCHED_SMT
925 bool "SMT (Hyperthreading) scheduler support"
926 depends on SMP
927 ---help---
928 SMT scheduler support improves the CPU scheduler's decision making
929 when dealing with Intel Pentium 4 chips with HyperThreading at a
930 cost of slightly increased overhead in some places. If unsure say
931 N here.
932
933 config SCHED_MC
934 def_bool y
935 prompt "Multi-core scheduler support"
936 depends on SMP
937 ---help---
938 Multi-core scheduler support improves the CPU scheduler's decision
939 making when dealing with multi-core CPU chips at a cost of slightly
940 increased overhead in some places. If unsure say N here.
941
942 config SCHED_MC_PRIO
943 bool "CPU core priorities scheduler support"
944 depends on SCHED_MC && CPU_SUP_INTEL
945 select X86_INTEL_PSTATE
946 select CPU_FREQ
947 default y
948 ---help---
949 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
950 core ordering determined at manufacturing time, which allows
951 certain cores to reach higher turbo frequencies (when running
952 single threaded workloads) than others.
953
954 Enabling this kernel feature teaches the scheduler about
955 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
956 scheduler's CPU selection logic accordingly, so that higher
957 overall system performance can be achieved.
958
959 This feature will have no effect on CPUs without this feature.
960
961 If unsure say Y here.
962
963 source "kernel/Kconfig.preempt"
964
965 config UP_LATE_INIT
966 def_bool y
967 depends on !SMP && X86_LOCAL_APIC
968
969 config X86_UP_APIC
970 bool "Local APIC support on uniprocessors" if !PCI_MSI
971 default PCI_MSI
972 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
973 ---help---
974 A local APIC (Advanced Programmable Interrupt Controller) is an
975 integrated interrupt controller in the CPU. If you have a single-CPU
976 system which has a processor with a local APIC, you can say Y here to
977 enable and use it. If you say Y here even though your machine doesn't
978 have a local APIC, then the kernel will still run with no slowdown at
979 all. The local APIC supports CPU-generated self-interrupts (timer,
980 performance counters), and the NMI watchdog which detects hard
981 lockups.
982
983 config X86_UP_IOAPIC
984 bool "IO-APIC support on uniprocessors"
985 depends on X86_UP_APIC
986 ---help---
987 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
988 SMP-capable replacement for PC-style interrupt controllers. Most
989 SMP systems and many recent uniprocessor systems have one.
990
991 If you have a single-CPU system with an IO-APIC, you can say Y here
992 to use it. If you say Y here even though your machine doesn't have
993 an IO-APIC, then the kernel will still run with no slowdown at all.
994
995 config X86_LOCAL_APIC
996 def_bool y
997 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
998 select IRQ_DOMAIN_HIERARCHY
999 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1000
1001 config X86_IO_APIC
1002 def_bool y
1003 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1004
1005 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1006 bool "Reroute for broken boot IRQs"
1007 depends on X86_IO_APIC
1008 ---help---
1009 This option enables a workaround that fixes a source of
1010 spurious interrupts. This is recommended when threaded
1011 interrupt handling is used on systems where the generation of
1012 superfluous "boot interrupts" cannot be disabled.
1013
1014 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1015 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1016 kernel does during interrupt handling). On chipsets where this
1017 boot IRQ generation cannot be disabled, this workaround keeps
1018 the original IRQ line masked so that only the equivalent "boot
1019 IRQ" is delivered to the CPUs. The workaround also tells the
1020 kernel to set up the IRQ handler on the boot IRQ line. In this
1021 way only one interrupt is delivered to the kernel. Otherwise
1022 the spurious second interrupt may cause the kernel to bring
1023 down (vital) interrupt lines.
1024
1025 Only affects "broken" chipsets. Interrupt sharing may be
1026 increased on these systems.
1027
1028 config X86_MCE
1029 bool "Machine Check / overheating reporting"
1030 select GENERIC_ALLOCATOR
1031 default y
1032 ---help---
1033 Machine Check support allows the processor to notify the
1034 kernel if it detects a problem (e.g. overheating, data corruption).
1035 The action the kernel takes depends on the severity of the problem,
1036 ranging from warning messages to halting the machine.
1037
1038 config X86_MCE_INTEL
1039 def_bool y
1040 prompt "Intel MCE features"
1041 depends on X86_MCE && X86_LOCAL_APIC
1042 ---help---
1043 Additional support for intel specific MCE features such as
1044 the thermal monitor.
1045
1046 config X86_MCE_AMD
1047 def_bool y
1048 prompt "AMD MCE features"
1049 depends on X86_MCE && X86_LOCAL_APIC
1050 ---help---
1051 Additional support for AMD specific MCE features such as
1052 the DRAM Error Threshold.
1053
1054 config X86_ANCIENT_MCE
1055 bool "Support for old Pentium 5 / WinChip machine checks"
1056 depends on X86_32 && X86_MCE
1057 ---help---
1058 Include support for machine check handling on old Pentium 5 or WinChip
1059 systems. These typically need to be enabled explicitly on the command
1060 line.
1061
1062 config X86_MCE_THRESHOLD
1063 depends on X86_MCE_AMD || X86_MCE_INTEL
1064 def_bool y
1065
1066 config X86_MCE_INJECT
1067 depends on X86_MCE
1068 tristate "Machine check injector support"
1069 ---help---
1070 Provide support for injecting machine checks for testing purposes.
1071 If you don't know what a machine check is and you don't do kernel
1072 QA it is safe to say n.
1073
1074 config X86_THERMAL_VECTOR
1075 def_bool y
1076 depends on X86_MCE_INTEL
1077
1078 source "arch/x86/events/Kconfig"
1079
1080 config X86_LEGACY_VM86
1081 bool "Legacy VM86 support"
1082 default n
1083 depends on X86_32
1084 ---help---
1085 This option allows user programs to put the CPU into V8086
1086 mode, which is an 80286-era approximation of 16-bit real mode.
1087
1088 Some very old versions of X and/or vbetool require this option
1089 for user mode setting. Similarly, DOSEMU will use it if
1090 available to accelerate real mode DOS programs. However, any
1091 recent version of DOSEMU, X, or vbetool should be fully
1092 functional even without kernel VM86 support, as they will all
1093 fall back to software emulation. Nevertheless, if you are using
1094 a 16-bit DOS program where 16-bit performance matters, vm86
1095 mode might be faster than emulation and you might want to
1096 enable this option.
1097
1098 Note that any app that works on a 64-bit kernel is unlikely to
1099 need this option, as 64-bit kernels don't, and can't, support
1100 V8086 mode. This option is also unrelated to 16-bit protected
1101 mode and is not needed to run most 16-bit programs under Wine.
1102
1103 Enabling this option increases the complexity of the kernel
1104 and slows down exception handling a tiny bit.
1105
1106 If unsure, say N here.
1107
1108 config VM86
1109 bool
1110 default X86_LEGACY_VM86
1111
1112 config X86_16BIT
1113 bool "Enable support for 16-bit segments" if EXPERT
1114 default y
1115 depends on MODIFY_LDT_SYSCALL
1116 ---help---
1117 This option is required by programs like Wine to run 16-bit
1118 protected mode legacy code on x86 processors. Disabling
1119 this option saves about 300 bytes on i386, or around 6K text
1120 plus 16K runtime memory on x86-64,
1121
1122 config X86_ESPFIX32
1123 def_bool y
1124 depends on X86_16BIT && X86_32
1125
1126 config X86_ESPFIX64
1127 def_bool y
1128 depends on X86_16BIT && X86_64
1129
1130 config X86_VSYSCALL_EMULATION
1131 bool "Enable vsyscall emulation" if EXPERT
1132 default y
1133 depends on X86_64
1134 ---help---
1135 This enables emulation of the legacy vsyscall page. Disabling
1136 it is roughly equivalent to booting with vsyscall=none, except
1137 that it will also disable the helpful warning if a program
1138 tries to use a vsyscall. With this option set to N, offending
1139 programs will just segfault, citing addresses of the form
1140 0xffffffffff600?00.
1141
1142 This option is required by many programs built before 2013, and
1143 care should be used even with newer programs if set to N.
1144
1145 Disabling this option saves about 7K of kernel size and
1146 possibly 4K of additional runtime pagetable memory.
1147
1148 config TOSHIBA
1149 tristate "Toshiba Laptop support"
1150 depends on X86_32
1151 ---help---
1152 This adds a driver to safely access the System Management Mode of
1153 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1154 not work on models with a Phoenix BIOS. The System Management Mode
1155 is used to set the BIOS and power saving options on Toshiba portables.
1156
1157 For information on utilities to make use of this driver see the
1158 Toshiba Linux utilities web site at:
1159 <http://www.buzzard.org.uk/toshiba/>.
1160
1161 Say Y if you intend to run this kernel on a Toshiba portable.
1162 Say N otherwise.
1163
1164 config I8K
1165 tristate "Dell i8k legacy laptop support"
1166 select HWMON
1167 select SENSORS_DELL_SMM
1168 ---help---
1169 This option enables legacy /proc/i8k userspace interface in hwmon
1170 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1171 temperature and allows controlling fan speeds of Dell laptops via
1172 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1173 it reports also power and hotkey status. For fan speed control is
1174 needed userspace package i8kutils.
1175
1176 Say Y if you intend to run this kernel on old Dell laptops or want to
1177 use userspace package i8kutils.
1178 Say N otherwise.
1179
1180 config X86_REBOOTFIXUPS
1181 bool "Enable X86 board specific fixups for reboot"
1182 depends on X86_32
1183 ---help---
1184 This enables chipset and/or board specific fixups to be done
1185 in order to get reboot to work correctly. This is only needed on
1186 some combinations of hardware and BIOS. The symptom, for which
1187 this config is intended, is when reboot ends with a stalled/hung
1188 system.
1189
1190 Currently, the only fixup is for the Geode machines using
1191 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1192
1193 Say Y if you want to enable the fixup. Currently, it's safe to
1194 enable this option even if you don't need it.
1195 Say N otherwise.
1196
1197 config MICROCODE
1198 bool "CPU microcode loading support"
1199 default y
1200 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1201 select FW_LOADER
1202 ---help---
1203 If you say Y here, you will be able to update the microcode on
1204 Intel and AMD processors. The Intel support is for the IA32 family,
1205 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1206 AMD support is for families 0x10 and later. You will obviously need
1207 the actual microcode binary data itself which is not shipped with
1208 the Linux kernel.
1209
1210 The preferred method to load microcode from a detached initrd is described
1211 in Documentation/x86/early-microcode.txt. For that you need to enable
1212 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1213 initrd for microcode blobs.
1214
1215 In addition, you can build-in the microcode into the kernel. For that you
1216 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1217 to the CONFIG_EXTRA_FIRMWARE config option.
1218
1219 config MICROCODE_INTEL
1220 bool "Intel microcode loading support"
1221 depends on MICROCODE
1222 default MICROCODE
1223 select FW_LOADER
1224 ---help---
1225 This options enables microcode patch loading support for Intel
1226 processors.
1227
1228 For the current Intel microcode data package go to
1229 <https://downloadcenter.intel.com> and search for
1230 'Linux Processor Microcode Data File'.
1231
1232 config MICROCODE_AMD
1233 bool "AMD microcode loading support"
1234 depends on MICROCODE
1235 select FW_LOADER
1236 ---help---
1237 If you select this option, microcode patch loading support for AMD
1238 processors will be enabled.
1239
1240 config MICROCODE_OLD_INTERFACE
1241 def_bool y
1242 depends on MICROCODE
1243
1244 config X86_MSR
1245 tristate "/dev/cpu/*/msr - Model-specific register support"
1246 ---help---
1247 This device gives privileged processes access to the x86
1248 Model-Specific Registers (MSRs). It is a character device with
1249 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1250 MSR accesses are directed to a specific CPU on multi-processor
1251 systems.
1252
1253 config X86_CPUID
1254 tristate "/dev/cpu/*/cpuid - CPU information support"
1255 ---help---
1256 This device gives processes access to the x86 CPUID instruction to
1257 be executed on a specific processor. It is a character device
1258 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1259 /dev/cpu/31/cpuid.
1260
1261 choice
1262 prompt "High Memory Support"
1263 default HIGHMEM4G
1264 depends on X86_32
1265
1266 config NOHIGHMEM
1267 bool "off"
1268 ---help---
1269 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1270 However, the address space of 32-bit x86 processors is only 4
1271 Gigabytes large. That means that, if you have a large amount of
1272 physical memory, not all of it can be "permanently mapped" by the
1273 kernel. The physical memory that's not permanently mapped is called
1274 "high memory".
1275
1276 If you are compiling a kernel which will never run on a machine with
1277 more than 1 Gigabyte total physical RAM, answer "off" here (default
1278 choice and suitable for most users). This will result in a "3GB/1GB"
1279 split: 3GB are mapped so that each process sees a 3GB virtual memory
1280 space and the remaining part of the 4GB virtual memory space is used
1281 by the kernel to permanently map as much physical memory as
1282 possible.
1283
1284 If the machine has between 1 and 4 Gigabytes physical RAM, then
1285 answer "4GB" here.
1286
1287 If more than 4 Gigabytes is used then answer "64GB" here. This
1288 selection turns Intel PAE (Physical Address Extension) mode on.
1289 PAE implements 3-level paging on IA32 processors. PAE is fully
1290 supported by Linux, PAE mode is implemented on all recent Intel
1291 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1292 then the kernel will not boot on CPUs that don't support PAE!
1293
1294 The actual amount of total physical memory will either be
1295 auto detected or can be forced by using a kernel command line option
1296 such as "mem=256M". (Try "man bootparam" or see the documentation of
1297 your boot loader (lilo or loadlin) about how to pass options to the
1298 kernel at boot time.)
1299
1300 If unsure, say "off".
1301
1302 config HIGHMEM4G
1303 bool "4GB"
1304 ---help---
1305 Select this if you have a 32-bit processor and between 1 and 4
1306 gigabytes of physical RAM.
1307
1308 config HIGHMEM64G
1309 bool "64GB"
1310 depends on !M486
1311 select X86_PAE
1312 ---help---
1313 Select this if you have a 32-bit processor and more than 4
1314 gigabytes of physical RAM.
1315
1316 endchoice
1317
1318 choice
1319 prompt "Memory split" if EXPERT
1320 default VMSPLIT_3G
1321 depends on X86_32
1322 ---help---
1323 Select the desired split between kernel and user memory.
1324
1325 If the address range available to the kernel is less than the
1326 physical memory installed, the remaining memory will be available
1327 as "high memory". Accessing high memory is a little more costly
1328 than low memory, as it needs to be mapped into the kernel first.
1329 Note that increasing the kernel address space limits the range
1330 available to user programs, making the address space there
1331 tighter. Selecting anything other than the default 3G/1G split
1332 will also likely make your kernel incompatible with binary-only
1333 kernel modules.
1334
1335 If you are not absolutely sure what you are doing, leave this
1336 option alone!
1337
1338 config VMSPLIT_3G
1339 bool "3G/1G user/kernel split"
1340 config VMSPLIT_3G_OPT
1341 depends on !X86_PAE
1342 bool "3G/1G user/kernel split (for full 1G low memory)"
1343 config VMSPLIT_2G
1344 bool "2G/2G user/kernel split"
1345 config VMSPLIT_2G_OPT
1346 depends on !X86_PAE
1347 bool "2G/2G user/kernel split (for full 2G low memory)"
1348 config VMSPLIT_1G
1349 bool "1G/3G user/kernel split"
1350 endchoice
1351
1352 config PAGE_OFFSET
1353 hex
1354 default 0xB0000000 if VMSPLIT_3G_OPT
1355 default 0x80000000 if VMSPLIT_2G
1356 default 0x78000000 if VMSPLIT_2G_OPT
1357 default 0x40000000 if VMSPLIT_1G
1358 default 0xC0000000
1359 depends on X86_32
1360
1361 config HIGHMEM
1362 def_bool y
1363 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1364
1365 config X86_PAE
1366 bool "PAE (Physical Address Extension) Support"
1367 depends on X86_32 && !HIGHMEM4G
1368 select SWIOTLB
1369 ---help---
1370 PAE is required for NX support, and furthermore enables
1371 larger swapspace support for non-overcommit purposes. It
1372 has the cost of more pagetable lookup overhead, and also
1373 consumes more pagetable space per process.
1374
1375 config ARCH_PHYS_ADDR_T_64BIT
1376 def_bool y
1377 depends on X86_64 || X86_PAE
1378
1379 config ARCH_DMA_ADDR_T_64BIT
1380 def_bool y
1381 depends on X86_64 || HIGHMEM64G
1382
1383 config X86_DIRECT_GBPAGES
1384 def_bool y
1385 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1386 ---help---
1387 Certain kernel features effectively disable kernel
1388 linear 1 GB mappings (even if the CPU otherwise
1389 supports them), so don't confuse the user by printing
1390 that we have them enabled.
1391
1392 # Common NUMA Features
1393 config NUMA
1394 bool "Numa Memory Allocation and Scheduler Support"
1395 depends on SMP
1396 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1397 default y if X86_BIGSMP
1398 ---help---
1399 Enable NUMA (Non Uniform Memory Access) support.
1400
1401 The kernel will try to allocate memory used by a CPU on the
1402 local memory controller of the CPU and add some more
1403 NUMA awareness to the kernel.
1404
1405 For 64-bit this is recommended if the system is Intel Core i7
1406 (or later), AMD Opteron, or EM64T NUMA.
1407
1408 For 32-bit this is only needed if you boot a 32-bit
1409 kernel on a 64-bit NUMA platform.
1410
1411 Otherwise, you should say N.
1412
1413 config AMD_NUMA
1414 def_bool y
1415 prompt "Old style AMD Opteron NUMA detection"
1416 depends on X86_64 && NUMA && PCI
1417 ---help---
1418 Enable AMD NUMA node topology detection. You should say Y here if
1419 you have a multi processor AMD system. This uses an old method to
1420 read the NUMA configuration directly from the builtin Northbridge
1421 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1422 which also takes priority if both are compiled in.
1423
1424 config X86_64_ACPI_NUMA
1425 def_bool y
1426 prompt "ACPI NUMA detection"
1427 depends on X86_64 && NUMA && ACPI && PCI
1428 select ACPI_NUMA
1429 ---help---
1430 Enable ACPI SRAT based node topology detection.
1431
1432 # Some NUMA nodes have memory ranges that span
1433 # other nodes. Even though a pfn is valid and
1434 # between a node's start and end pfns, it may not
1435 # reside on that node. See memmap_init_zone()
1436 # for details.
1437 config NODES_SPAN_OTHER_NODES
1438 def_bool y
1439 depends on X86_64_ACPI_NUMA
1440
1441 config NUMA_EMU
1442 bool "NUMA emulation"
1443 depends on NUMA
1444 ---help---
1445 Enable NUMA emulation. A flat machine will be split
1446 into virtual nodes when booted with "numa=fake=N", where N is the
1447 number of nodes. This is only useful for debugging.
1448
1449 config NODES_SHIFT
1450 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1451 range 1 10
1452 default "10" if MAXSMP
1453 default "6" if X86_64
1454 default "3"
1455 depends on NEED_MULTIPLE_NODES
1456 ---help---
1457 Specify the maximum number of NUMA Nodes available on the target
1458 system. Increases memory reserved to accommodate various tables.
1459
1460 config ARCH_HAVE_MEMORY_PRESENT
1461 def_bool y
1462 depends on X86_32 && DISCONTIGMEM
1463
1464 config NEED_NODE_MEMMAP_SIZE
1465 def_bool y
1466 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1467
1468 config ARCH_FLATMEM_ENABLE
1469 def_bool y
1470 depends on X86_32 && !NUMA
1471
1472 config ARCH_DISCONTIGMEM_ENABLE
1473 def_bool y
1474 depends on NUMA && X86_32
1475
1476 config ARCH_DISCONTIGMEM_DEFAULT
1477 def_bool y
1478 depends on NUMA && X86_32
1479
1480 config ARCH_SPARSEMEM_ENABLE
1481 def_bool y
1482 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1483 select SPARSEMEM_STATIC if X86_32
1484 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1485
1486 config ARCH_SPARSEMEM_DEFAULT
1487 def_bool y
1488 depends on X86_64
1489
1490 config ARCH_SELECT_MEMORY_MODEL
1491 def_bool y
1492 depends on ARCH_SPARSEMEM_ENABLE
1493
1494 config ARCH_MEMORY_PROBE
1495 bool "Enable sysfs memory/probe interface"
1496 depends on X86_64 && MEMORY_HOTPLUG
1497 help
1498 This option enables a sysfs memory/probe interface for testing.
1499 See Documentation/memory-hotplug.txt for more information.
1500 If you are unsure how to answer this question, answer N.
1501
1502 config ARCH_PROC_KCORE_TEXT
1503 def_bool y
1504 depends on X86_64 && PROC_KCORE
1505
1506 config ILLEGAL_POINTER_VALUE
1507 hex
1508 default 0 if X86_32
1509 default 0xdead000000000000 if X86_64
1510
1511 source "mm/Kconfig"
1512
1513 config X86_PMEM_LEGACY_DEVICE
1514 bool
1515
1516 config X86_PMEM_LEGACY
1517 tristate "Support non-standard NVDIMMs and ADR protected memory"
1518 depends on PHYS_ADDR_T_64BIT
1519 depends on BLK_DEV
1520 select X86_PMEM_LEGACY_DEVICE
1521 select LIBNVDIMM
1522 help
1523 Treat memory marked using the non-standard e820 type of 12 as used
1524 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1525 The kernel will offer these regions to the 'pmem' driver so
1526 they can be used for persistent storage.
1527
1528 Say Y if unsure.
1529
1530 config HIGHPTE
1531 bool "Allocate 3rd-level pagetables from highmem"
1532 depends on HIGHMEM
1533 ---help---
1534 The VM uses one page table entry for each page of physical memory.
1535 For systems with a lot of RAM, this can be wasteful of precious
1536 low memory. Setting this option will put user-space page table
1537 entries in high memory.
1538
1539 config X86_CHECK_BIOS_CORRUPTION
1540 bool "Check for low memory corruption"
1541 ---help---
1542 Periodically check for memory corruption in low memory, which
1543 is suspected to be caused by BIOS. Even when enabled in the
1544 configuration, it is disabled at runtime. Enable it by
1545 setting "memory_corruption_check=1" on the kernel command
1546 line. By default it scans the low 64k of memory every 60
1547 seconds; see the memory_corruption_check_size and
1548 memory_corruption_check_period parameters in
1549 Documentation/kernel-parameters.txt to adjust this.
1550
1551 When enabled with the default parameters, this option has
1552 almost no overhead, as it reserves a relatively small amount
1553 of memory and scans it infrequently. It both detects corruption
1554 and prevents it from affecting the running system.
1555
1556 It is, however, intended as a diagnostic tool; if repeatable
1557 BIOS-originated corruption always affects the same memory,
1558 you can use memmap= to prevent the kernel from using that
1559 memory.
1560
1561 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1562 bool "Set the default setting of memory_corruption_check"
1563 depends on X86_CHECK_BIOS_CORRUPTION
1564 default y
1565 ---help---
1566 Set whether the default state of memory_corruption_check is
1567 on or off.
1568
1569 config X86_RESERVE_LOW
1570 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1571 default 64
1572 range 4 640
1573 ---help---
1574 Specify the amount of low memory to reserve for the BIOS.
1575
1576 The first page contains BIOS data structures that the kernel
1577 must not use, so that page must always be reserved.
1578
1579 By default we reserve the first 64K of physical RAM, as a
1580 number of BIOSes are known to corrupt that memory range
1581 during events such as suspend/resume or monitor cable
1582 insertion, so it must not be used by the kernel.
1583
1584 You can set this to 4 if you are absolutely sure that you
1585 trust the BIOS to get all its memory reservations and usages
1586 right. If you know your BIOS have problems beyond the
1587 default 64K area, you can set this to 640 to avoid using the
1588 entire low memory range.
1589
1590 If you have doubts about the BIOS (e.g. suspend/resume does
1591 not work or there's kernel crashes after certain hardware
1592 hotplug events) then you might want to enable
1593 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1594 typical corruption patterns.
1595
1596 Leave this to the default value of 64 if you are unsure.
1597
1598 config MATH_EMULATION
1599 bool
1600 depends on MODIFY_LDT_SYSCALL
1601 prompt "Math emulation" if X86_32
1602 ---help---
1603 Linux can emulate a math coprocessor (used for floating point
1604 operations) if you don't have one. 486DX and Pentium processors have
1605 a math coprocessor built in, 486SX and 386 do not, unless you added
1606 a 487DX or 387, respectively. (The messages during boot time can
1607 give you some hints here ["man dmesg"].) Everyone needs either a
1608 coprocessor or this emulation.
1609
1610 If you don't have a math coprocessor, you need to say Y here; if you
1611 say Y here even though you have a coprocessor, the coprocessor will
1612 be used nevertheless. (This behavior can be changed with the kernel
1613 command line option "no387", which comes handy if your coprocessor
1614 is broken. Try "man bootparam" or see the documentation of your boot
1615 loader (lilo or loadlin) about how to pass options to the kernel at
1616 boot time.) This means that it is a good idea to say Y here if you
1617 intend to use this kernel on different machines.
1618
1619 More information about the internals of the Linux math coprocessor
1620 emulation can be found in <file:arch/x86/math-emu/README>.
1621
1622 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1623 kernel, it won't hurt.
1624
1625 config MTRR
1626 def_bool y
1627 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1628 ---help---
1629 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1630 the Memory Type Range Registers (MTRRs) may be used to control
1631 processor access to memory ranges. This is most useful if you have
1632 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1633 allows bus write transfers to be combined into a larger transfer
1634 before bursting over the PCI/AGP bus. This can increase performance
1635 of image write operations 2.5 times or more. Saying Y here creates a
1636 /proc/mtrr file which may be used to manipulate your processor's
1637 MTRRs. Typically the X server should use this.
1638
1639 This code has a reasonably generic interface so that similar
1640 control registers on other processors can be easily supported
1641 as well:
1642
1643 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1644 Registers (ARRs) which provide a similar functionality to MTRRs. For
1645 these, the ARRs are used to emulate the MTRRs.
1646 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1647 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1648 write-combining. All of these processors are supported by this code
1649 and it makes sense to say Y here if you have one of them.
1650
1651 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1652 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1653 can lead to all sorts of problems, so it's good to say Y here.
1654
1655 You can safely say Y even if your machine doesn't have MTRRs, you'll
1656 just add about 9 KB to your kernel.
1657
1658 See <file:Documentation/x86/mtrr.txt> for more information.
1659
1660 config MTRR_SANITIZER
1661 def_bool y
1662 prompt "MTRR cleanup support"
1663 depends on MTRR
1664 ---help---
1665 Convert MTRR layout from continuous to discrete, so X drivers can
1666 add writeback entries.
1667
1668 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1669 The largest mtrr entry size for a continuous block can be set with
1670 mtrr_chunk_size.
1671
1672 If unsure, say Y.
1673
1674 config MTRR_SANITIZER_ENABLE_DEFAULT
1675 int "MTRR cleanup enable value (0-1)"
1676 range 0 1
1677 default "0"
1678 depends on MTRR_SANITIZER
1679 ---help---
1680 Enable mtrr cleanup default value
1681
1682 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1683 int "MTRR cleanup spare reg num (0-7)"
1684 range 0 7
1685 default "1"
1686 depends on MTRR_SANITIZER
1687 ---help---
1688 mtrr cleanup spare entries default, it can be changed via
1689 mtrr_spare_reg_nr=N on the kernel command line.
1690
1691 config X86_PAT
1692 def_bool y
1693 prompt "x86 PAT support" if EXPERT
1694 depends on MTRR
1695 ---help---
1696 Use PAT attributes to setup page level cache control.
1697
1698 PATs are the modern equivalents of MTRRs and are much more
1699 flexible than MTRRs.
1700
1701 Say N here if you see bootup problems (boot crash, boot hang,
1702 spontaneous reboots) or a non-working video driver.
1703
1704 If unsure, say Y.
1705
1706 config ARCH_USES_PG_UNCACHED
1707 def_bool y
1708 depends on X86_PAT
1709
1710 config ARCH_RANDOM
1711 def_bool y
1712 prompt "x86 architectural random number generator" if EXPERT
1713 ---help---
1714 Enable the x86 architectural RDRAND instruction
1715 (Intel Bull Mountain technology) to generate random numbers.
1716 If supported, this is a high bandwidth, cryptographically
1717 secure hardware random number generator.
1718
1719 config X86_SMAP
1720 def_bool y
1721 prompt "Supervisor Mode Access Prevention" if EXPERT
1722 ---help---
1723 Supervisor Mode Access Prevention (SMAP) is a security
1724 feature in newer Intel processors. There is a small
1725 performance cost if this enabled and turned on; there is
1726 also a small increase in the kernel size if this is enabled.
1727
1728 If unsure, say Y.
1729
1730 config X86_INTEL_MPX
1731 prompt "Intel MPX (Memory Protection Extensions)"
1732 def_bool n
1733 depends on CPU_SUP_INTEL
1734 ---help---
1735 MPX provides hardware features that can be used in
1736 conjunction with compiler-instrumented code to check
1737 memory references. It is designed to detect buffer
1738 overflow or underflow bugs.
1739
1740 This option enables running applications which are
1741 instrumented or otherwise use MPX. It does not use MPX
1742 itself inside the kernel or to protect the kernel
1743 against bad memory references.
1744
1745 Enabling this option will make the kernel larger:
1746 ~8k of kernel text and 36 bytes of data on a 64-bit
1747 defconfig. It adds a long to the 'mm_struct' which
1748 will increase the kernel memory overhead of each
1749 process and adds some branches to paths used during
1750 exec() and munmap().
1751
1752 For details, see Documentation/x86/intel_mpx.txt
1753
1754 If unsure, say N.
1755
1756 config X86_INTEL_MEMORY_PROTECTION_KEYS
1757 prompt "Intel Memory Protection Keys"
1758 def_bool y
1759 # Note: only available in 64-bit mode
1760 depends on CPU_SUP_INTEL && X86_64
1761 ---help---
1762 Memory Protection Keys provides a mechanism for enforcing
1763 page-based protections, but without requiring modification of the
1764 page tables when an application changes protection domains.
1765
1766 For details, see Documentation/x86/protection-keys.txt
1767
1768 If unsure, say y.
1769
1770 config EFI
1771 bool "EFI runtime service support"
1772 depends on ACPI
1773 select UCS2_STRING
1774 select EFI_RUNTIME_WRAPPERS
1775 ---help---
1776 This enables the kernel to use EFI runtime services that are
1777 available (such as the EFI variable services).
1778
1779 This option is only useful on systems that have EFI firmware.
1780 In addition, you should use the latest ELILO loader available
1781 at <http://elilo.sourceforge.net> in order to take advantage
1782 of EFI runtime services. However, even with this option, the
1783 resultant kernel should continue to boot on existing non-EFI
1784 platforms.
1785
1786 config EFI_STUB
1787 bool "EFI stub support"
1788 depends on EFI && !X86_USE_3DNOW
1789 select RELOCATABLE
1790 ---help---
1791 This kernel feature allows a bzImage to be loaded directly
1792 by EFI firmware without the use of a bootloader.
1793
1794 See Documentation/efi-stub.txt for more information.
1795
1796 config EFI_MIXED
1797 bool "EFI mixed-mode support"
1798 depends on EFI_STUB && X86_64
1799 ---help---
1800 Enabling this feature allows a 64-bit kernel to be booted
1801 on a 32-bit firmware, provided that your CPU supports 64-bit
1802 mode.
1803
1804 Note that it is not possible to boot a mixed-mode enabled
1805 kernel via the EFI boot stub - a bootloader that supports
1806 the EFI handover protocol must be used.
1807
1808 If unsure, say N.
1809
1810 config SECCOMP
1811 def_bool y
1812 prompt "Enable seccomp to safely compute untrusted bytecode"
1813 ---help---
1814 This kernel feature is useful for number crunching applications
1815 that may need to compute untrusted bytecode during their
1816 execution. By using pipes or other transports made available to
1817 the process as file descriptors supporting the read/write
1818 syscalls, it's possible to isolate those applications in
1819 their own address space using seccomp. Once seccomp is
1820 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1821 and the task is only allowed to execute a few safe syscalls
1822 defined by each seccomp mode.
1823
1824 If unsure, say Y. Only embedded should say N here.
1825
1826 source kernel/Kconfig.hz
1827
1828 config KEXEC
1829 bool "kexec system call"
1830 select KEXEC_CORE
1831 ---help---
1832 kexec is a system call that implements the ability to shutdown your
1833 current kernel, and to start another kernel. It is like a reboot
1834 but it is independent of the system firmware. And like a reboot
1835 you can start any kernel with it, not just Linux.
1836
1837 The name comes from the similarity to the exec system call.
1838
1839 It is an ongoing process to be certain the hardware in a machine
1840 is properly shutdown, so do not be surprised if this code does not
1841 initially work for you. As of this writing the exact hardware
1842 interface is strongly in flux, so no good recommendation can be
1843 made.
1844
1845 config KEXEC_FILE
1846 bool "kexec file based system call"
1847 select KEXEC_CORE
1848 select BUILD_BIN2C
1849 depends on X86_64
1850 depends on CRYPTO=y
1851 depends on CRYPTO_SHA256=y
1852 ---help---
1853 This is new version of kexec system call. This system call is
1854 file based and takes file descriptors as system call argument
1855 for kernel and initramfs as opposed to list of segments as
1856 accepted by previous system call.
1857
1858 config KEXEC_VERIFY_SIG
1859 bool "Verify kernel signature during kexec_file_load() syscall"
1860 depends on KEXEC_FILE
1861 ---help---
1862 This option makes kernel signature verification mandatory for
1863 the kexec_file_load() syscall.
1864
1865 In addition to that option, you need to enable signature
1866 verification for the corresponding kernel image type being
1867 loaded in order for this to work.
1868
1869 config KEXEC_BZIMAGE_VERIFY_SIG
1870 bool "Enable bzImage signature verification support"
1871 depends on KEXEC_VERIFY_SIG
1872 depends on SIGNED_PE_FILE_VERIFICATION
1873 select SYSTEM_TRUSTED_KEYRING
1874 ---help---
1875 Enable bzImage signature verification support.
1876
1877 config CRASH_DUMP
1878 bool "kernel crash dumps"
1879 depends on X86_64 || (X86_32 && HIGHMEM)
1880 ---help---
1881 Generate crash dump after being started by kexec.
1882 This should be normally only set in special crash dump kernels
1883 which are loaded in the main kernel with kexec-tools into
1884 a specially reserved region and then later executed after
1885 a crash by kdump/kexec. The crash dump kernel must be compiled
1886 to a memory address not used by the main kernel or BIOS using
1887 PHYSICAL_START, or it must be built as a relocatable image
1888 (CONFIG_RELOCATABLE=y).
1889 For more details see Documentation/kdump/kdump.txt
1890
1891 config KEXEC_JUMP
1892 bool "kexec jump"
1893 depends on KEXEC && HIBERNATION
1894 ---help---
1895 Jump between original kernel and kexeced kernel and invoke
1896 code in physical address mode via KEXEC
1897
1898 config PHYSICAL_START
1899 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1900 default "0x1000000"
1901 ---help---
1902 This gives the physical address where the kernel is loaded.
1903
1904 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1905 bzImage will decompress itself to above physical address and
1906 run from there. Otherwise, bzImage will run from the address where
1907 it has been loaded by the boot loader and will ignore above physical
1908 address.
1909
1910 In normal kdump cases one does not have to set/change this option
1911 as now bzImage can be compiled as a completely relocatable image
1912 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1913 address. This option is mainly useful for the folks who don't want
1914 to use a bzImage for capturing the crash dump and want to use a
1915 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1916 to be specifically compiled to run from a specific memory area
1917 (normally a reserved region) and this option comes handy.
1918
1919 So if you are using bzImage for capturing the crash dump,
1920 leave the value here unchanged to 0x1000000 and set
1921 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1922 for capturing the crash dump change this value to start of
1923 the reserved region. In other words, it can be set based on
1924 the "X" value as specified in the "crashkernel=YM@XM"
1925 command line boot parameter passed to the panic-ed
1926 kernel. Please take a look at Documentation/kdump/kdump.txt
1927 for more details about crash dumps.
1928
1929 Usage of bzImage for capturing the crash dump is recommended as
1930 one does not have to build two kernels. Same kernel can be used
1931 as production kernel and capture kernel. Above option should have
1932 gone away after relocatable bzImage support is introduced. But it
1933 is present because there are users out there who continue to use
1934 vmlinux for dump capture. This option should go away down the
1935 line.
1936
1937 Don't change this unless you know what you are doing.
1938
1939 config RELOCATABLE
1940 bool "Build a relocatable kernel"
1941 default y
1942 ---help---
1943 This builds a kernel image that retains relocation information
1944 so it can be loaded someplace besides the default 1MB.
1945 The relocations tend to make the kernel binary about 10% larger,
1946 but are discarded at runtime.
1947
1948 One use is for the kexec on panic case where the recovery kernel
1949 must live at a different physical address than the primary
1950 kernel.
1951
1952 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1953 it has been loaded at and the compile time physical address
1954 (CONFIG_PHYSICAL_START) is used as the minimum location.
1955
1956 config RANDOMIZE_BASE
1957 bool "Randomize the address of the kernel image (KASLR)"
1958 depends on RELOCATABLE
1959 default n
1960 ---help---
1961 In support of Kernel Address Space Layout Randomization (KASLR),
1962 this randomizes the physical address at which the kernel image
1963 is decompressed and the virtual address where the kernel
1964 image is mapped, as a security feature that deters exploit
1965 attempts relying on knowledge of the location of kernel
1966 code internals.
1967
1968 On 64-bit, the kernel physical and virtual addresses are
1969 randomized separately. The physical address will be anywhere
1970 between 16MB and the top of physical memory (up to 64TB). The
1971 virtual address will be randomized from 16MB up to 1GB (9 bits
1972 of entropy). Note that this also reduces the memory space
1973 available to kernel modules from 1.5GB to 1GB.
1974
1975 On 32-bit, the kernel physical and virtual addresses are
1976 randomized together. They will be randomized from 16MB up to
1977 512MB (8 bits of entropy).
1978
1979 Entropy is generated using the RDRAND instruction if it is
1980 supported. If RDTSC is supported, its value is mixed into
1981 the entropy pool as well. If neither RDRAND nor RDTSC are
1982 supported, then entropy is read from the i8254 timer. The
1983 usable entropy is limited by the kernel being built using
1984 2GB addressing, and that PHYSICAL_ALIGN must be at a
1985 minimum of 2MB. As a result, only 10 bits of entropy are
1986 theoretically possible, but the implementations are further
1987 limited due to memory layouts.
1988
1989 If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot
1990 time. To enable it, boot with "kaslr" on the kernel command
1991 line (which will also disable hibernation).
1992
1993 If unsure, say N.
1994
1995 # Relocation on x86 needs some additional build support
1996 config X86_NEED_RELOCS
1997 def_bool y
1998 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1999
2000 config PHYSICAL_ALIGN
2001 hex "Alignment value to which kernel should be aligned"
2002 default "0x200000"
2003 range 0x2000 0x1000000 if X86_32
2004 range 0x200000 0x1000000 if X86_64
2005 ---help---
2006 This value puts the alignment restrictions on physical address
2007 where kernel is loaded and run from. Kernel is compiled for an
2008 address which meets above alignment restriction.
2009
2010 If bootloader loads the kernel at a non-aligned address and
2011 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2012 address aligned to above value and run from there.
2013
2014 If bootloader loads the kernel at a non-aligned address and
2015 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2016 load address and decompress itself to the address it has been
2017 compiled for and run from there. The address for which kernel is
2018 compiled already meets above alignment restrictions. Hence the
2019 end result is that kernel runs from a physical address meeting
2020 above alignment restrictions.
2021
2022 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2023 this value must be a multiple of 0x200000.
2024
2025 Don't change this unless you know what you are doing.
2026
2027 config RANDOMIZE_MEMORY
2028 bool "Randomize the kernel memory sections"
2029 depends on X86_64
2030 depends on RANDOMIZE_BASE
2031 default RANDOMIZE_BASE
2032 ---help---
2033 Randomizes the base virtual address of kernel memory sections
2034 (physical memory mapping, vmalloc & vmemmap). This security feature
2035 makes exploits relying on predictable memory locations less reliable.
2036
2037 The order of allocations remains unchanged. Entropy is generated in
2038 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2039 configuration have in average 30,000 different possible virtual
2040 addresses for each memory section.
2041
2042 If unsure, say N.
2043
2044 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2045 hex "Physical memory mapping padding" if EXPERT
2046 depends on RANDOMIZE_MEMORY
2047 default "0xa" if MEMORY_HOTPLUG
2048 default "0x0"
2049 range 0x1 0x40 if MEMORY_HOTPLUG
2050 range 0x0 0x40
2051 ---help---
2052 Define the padding in terabytes added to the existing physical
2053 memory size during kernel memory randomization. It is useful
2054 for memory hotplug support but reduces the entropy available for
2055 address randomization.
2056
2057 If unsure, leave at the default value.
2058
2059 config HOTPLUG_CPU
2060 bool "Support for hot-pluggable CPUs"
2061 depends on SMP
2062 ---help---
2063 Say Y here to allow turning CPUs off and on. CPUs can be
2064 controlled through /sys/devices/system/cpu.
2065 ( Note: power management support will enable this option
2066 automatically on SMP systems. )
2067 Say N if you want to disable CPU hotplug.
2068
2069 config BOOTPARAM_HOTPLUG_CPU0
2070 bool "Set default setting of cpu0_hotpluggable"
2071 default n
2072 depends on HOTPLUG_CPU
2073 ---help---
2074 Set whether default state of cpu0_hotpluggable is on or off.
2075
2076 Say Y here to enable CPU0 hotplug by default. If this switch
2077 is turned on, there is no need to give cpu0_hotplug kernel
2078 parameter and the CPU0 hotplug feature is enabled by default.
2079
2080 Please note: there are two known CPU0 dependencies if you want
2081 to enable the CPU0 hotplug feature either by this switch or by
2082 cpu0_hotplug kernel parameter.
2083
2084 First, resume from hibernate or suspend always starts from CPU0.
2085 So hibernate and suspend are prevented if CPU0 is offline.
2086
2087 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2088 offline if any interrupt can not migrate out of CPU0. There may
2089 be other CPU0 dependencies.
2090
2091 Please make sure the dependencies are under your control before
2092 you enable this feature.
2093
2094 Say N if you don't want to enable CPU0 hotplug feature by default.
2095 You still can enable the CPU0 hotplug feature at boot by kernel
2096 parameter cpu0_hotplug.
2097
2098 config DEBUG_HOTPLUG_CPU0
2099 def_bool n
2100 prompt "Debug CPU0 hotplug"
2101 depends on HOTPLUG_CPU
2102 ---help---
2103 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2104 soon as possible and boots up userspace with CPU0 offlined. User
2105 can online CPU0 back after boot time.
2106
2107 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2108 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2109 compilation or giving cpu0_hotplug kernel parameter at boot.
2110
2111 If unsure, say N.
2112
2113 config COMPAT_VDSO
2114 def_bool n
2115 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2116 depends on X86_32 || IA32_EMULATION
2117 ---help---
2118 Certain buggy versions of glibc will crash if they are
2119 presented with a 32-bit vDSO that is not mapped at the address
2120 indicated in its segment table.
2121
2122 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2123 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2124 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2125 the only released version with the bug, but OpenSUSE 9
2126 contains a buggy "glibc 2.3.2".
2127
2128 The symptom of the bug is that everything crashes on startup, saying:
2129 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2130
2131 Saying Y here changes the default value of the vdso32 boot
2132 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2133 This works around the glibc bug but hurts performance.
2134
2135 If unsure, say N: if you are compiling your own kernel, you
2136 are unlikely to be using a buggy version of glibc.
2137
2138 choice
2139 prompt "vsyscall table for legacy applications"
2140 depends on X86_64
2141 default LEGACY_VSYSCALL_EMULATE
2142 help
2143 Legacy user code that does not know how to find the vDSO expects
2144 to be able to issue three syscalls by calling fixed addresses in
2145 kernel space. Since this location is not randomized with ASLR,
2146 it can be used to assist security vulnerability exploitation.
2147
2148 This setting can be changed at boot time via the kernel command
2149 line parameter vsyscall=[native|emulate|none].
2150
2151 On a system with recent enough glibc (2.14 or newer) and no
2152 static binaries, you can say None without a performance penalty
2153 to improve security.
2154
2155 If unsure, select "Emulate".
2156
2157 config LEGACY_VSYSCALL_NATIVE
2158 bool "Native"
2159 help
2160 Actual executable code is located in the fixed vsyscall
2161 address mapping, implementing time() efficiently. Since
2162 this makes the mapping executable, it can be used during
2163 security vulnerability exploitation (traditionally as
2164 ROP gadgets). This configuration is not recommended.
2165
2166 config LEGACY_VSYSCALL_EMULATE
2167 bool "Emulate"
2168 help
2169 The kernel traps and emulates calls into the fixed
2170 vsyscall address mapping. This makes the mapping
2171 non-executable, but it still contains known contents,
2172 which could be used in certain rare security vulnerability
2173 exploits. This configuration is recommended when userspace
2174 still uses the vsyscall area.
2175
2176 config LEGACY_VSYSCALL_NONE
2177 bool "None"
2178 help
2179 There will be no vsyscall mapping at all. This will
2180 eliminate any risk of ASLR bypass due to the vsyscall
2181 fixed address mapping. Attempts to use the vsyscalls
2182 will be reported to dmesg, so that either old or
2183 malicious userspace programs can be identified.
2184
2185 endchoice
2186
2187 config CMDLINE_BOOL
2188 bool "Built-in kernel command line"
2189 ---help---
2190 Allow for specifying boot arguments to the kernel at
2191 build time. On some systems (e.g. embedded ones), it is
2192 necessary or convenient to provide some or all of the
2193 kernel boot arguments with the kernel itself (that is,
2194 to not rely on the boot loader to provide them.)
2195
2196 To compile command line arguments into the kernel,
2197 set this option to 'Y', then fill in the
2198 boot arguments in CONFIG_CMDLINE.
2199
2200 Systems with fully functional boot loaders (i.e. non-embedded)
2201 should leave this option set to 'N'.
2202
2203 config CMDLINE
2204 string "Built-in kernel command string"
2205 depends on CMDLINE_BOOL
2206 default ""
2207 ---help---
2208 Enter arguments here that should be compiled into the kernel
2209 image and used at boot time. If the boot loader provides a
2210 command line at boot time, it is appended to this string to
2211 form the full kernel command line, when the system boots.
2212
2213 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2214 change this behavior.
2215
2216 In most cases, the command line (whether built-in or provided
2217 by the boot loader) should specify the device for the root
2218 file system.
2219
2220 config CMDLINE_OVERRIDE
2221 bool "Built-in command line overrides boot loader arguments"
2222 depends on CMDLINE_BOOL
2223 ---help---
2224 Set this option to 'Y' to have the kernel ignore the boot loader
2225 command line, and use ONLY the built-in command line.
2226
2227 This is used to work around broken boot loaders. This should
2228 be set to 'N' under normal conditions.
2229
2230 config MODIFY_LDT_SYSCALL
2231 bool "Enable the LDT (local descriptor table)" if EXPERT
2232 default y
2233 ---help---
2234 Linux can allow user programs to install a per-process x86
2235 Local Descriptor Table (LDT) using the modify_ldt(2) system
2236 call. This is required to run 16-bit or segmented code such as
2237 DOSEMU or some Wine programs. It is also used by some very old
2238 threading libraries.
2239
2240 Enabling this feature adds a small amount of overhead to
2241 context switches and increases the low-level kernel attack
2242 surface. Disabling it removes the modify_ldt(2) system call.
2243
2244 Saying 'N' here may make sense for embedded or server kernels.
2245
2246 source "kernel/livepatch/Kconfig"
2247
2248 endmenu
2249
2250 config ARCH_ENABLE_MEMORY_HOTPLUG
2251 def_bool y
2252 depends on X86_64 || (X86_32 && HIGHMEM)
2253
2254 config ARCH_ENABLE_MEMORY_HOTREMOVE
2255 def_bool y
2256 depends on MEMORY_HOTPLUG
2257
2258 config USE_PERCPU_NUMA_NODE_ID
2259 def_bool y
2260 depends on NUMA
2261
2262 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2263 def_bool y
2264 depends on X86_64 || X86_PAE
2265
2266 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2267 def_bool y
2268 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2269
2270 menu "Power management and ACPI options"
2271
2272 config ARCH_HIBERNATION_HEADER
2273 def_bool y
2274 depends on X86_64 && HIBERNATION
2275
2276 source "kernel/power/Kconfig"
2277
2278 source "drivers/acpi/Kconfig"
2279
2280 source "drivers/sfi/Kconfig"
2281
2282 config X86_APM_BOOT
2283 def_bool y
2284 depends on APM
2285
2286 menuconfig APM
2287 tristate "APM (Advanced Power Management) BIOS support"
2288 depends on X86_32 && PM_SLEEP
2289 ---help---
2290 APM is a BIOS specification for saving power using several different
2291 techniques. This is mostly useful for battery powered laptops with
2292 APM compliant BIOSes. If you say Y here, the system time will be
2293 reset after a RESUME operation, the /proc/apm device will provide
2294 battery status information, and user-space programs will receive
2295 notification of APM "events" (e.g. battery status change).
2296
2297 If you select "Y" here, you can disable actual use of the APM
2298 BIOS by passing the "apm=off" option to the kernel at boot time.
2299
2300 Note that the APM support is almost completely disabled for
2301 machines with more than one CPU.
2302
2303 In order to use APM, you will need supporting software. For location
2304 and more information, read <file:Documentation/power/apm-acpi.txt>
2305 and the Battery Powered Linux mini-HOWTO, available from
2306 <http://www.tldp.org/docs.html#howto>.
2307
2308 This driver does not spin down disk drives (see the hdparm(8)
2309 manpage ("man 8 hdparm") for that), and it doesn't turn off
2310 VESA-compliant "green" monitors.
2311
2312 This driver does not support the TI 4000M TravelMate and the ACER
2313 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2314 desktop machines also don't have compliant BIOSes, and this driver
2315 may cause those machines to panic during the boot phase.
2316
2317 Generally, if you don't have a battery in your machine, there isn't
2318 much point in using this driver and you should say N. If you get
2319 random kernel OOPSes or reboots that don't seem to be related to
2320 anything, try disabling/enabling this option (or disabling/enabling
2321 APM in your BIOS).
2322
2323 Some other things you should try when experiencing seemingly random,
2324 "weird" problems:
2325
2326 1) make sure that you have enough swap space and that it is
2327 enabled.
2328 2) pass the "no-hlt" option to the kernel
2329 3) switch on floating point emulation in the kernel and pass
2330 the "no387" option to the kernel
2331 4) pass the "floppy=nodma" option to the kernel
2332 5) pass the "mem=4M" option to the kernel (thereby disabling
2333 all but the first 4 MB of RAM)
2334 6) make sure that the CPU is not over clocked.
2335 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2336 8) disable the cache from your BIOS settings
2337 9) install a fan for the video card or exchange video RAM
2338 10) install a better fan for the CPU
2339 11) exchange RAM chips
2340 12) exchange the motherboard.
2341
2342 To compile this driver as a module, choose M here: the
2343 module will be called apm.
2344
2345 if APM
2346
2347 config APM_IGNORE_USER_SUSPEND
2348 bool "Ignore USER SUSPEND"
2349 ---help---
2350 This option will ignore USER SUSPEND requests. On machines with a
2351 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2352 series notebooks, it is necessary to say Y because of a BIOS bug.
2353
2354 config APM_DO_ENABLE
2355 bool "Enable PM at boot time"
2356 ---help---
2357 Enable APM features at boot time. From page 36 of the APM BIOS
2358 specification: "When disabled, the APM BIOS does not automatically
2359 power manage devices, enter the Standby State, enter the Suspend
2360 State, or take power saving steps in response to CPU Idle calls."
2361 This driver will make CPU Idle calls when Linux is idle (unless this
2362 feature is turned off -- see "Do CPU IDLE calls", below). This
2363 should always save battery power, but more complicated APM features
2364 will be dependent on your BIOS implementation. You may need to turn
2365 this option off if your computer hangs at boot time when using APM
2366 support, or if it beeps continuously instead of suspending. Turn
2367 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2368 T400CDT. This is off by default since most machines do fine without
2369 this feature.
2370
2371 config APM_CPU_IDLE
2372 depends on CPU_IDLE
2373 bool "Make CPU Idle calls when idle"
2374 ---help---
2375 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2376 On some machines, this can activate improved power savings, such as
2377 a slowed CPU clock rate, when the machine is idle. These idle calls
2378 are made after the idle loop has run for some length of time (e.g.,
2379 333 mS). On some machines, this will cause a hang at boot time or
2380 whenever the CPU becomes idle. (On machines with more than one CPU,
2381 this option does nothing.)
2382
2383 config APM_DISPLAY_BLANK
2384 bool "Enable console blanking using APM"
2385 ---help---
2386 Enable console blanking using the APM. Some laptops can use this to
2387 turn off the LCD backlight when the screen blanker of the Linux
2388 virtual console blanks the screen. Note that this is only used by
2389 the virtual console screen blanker, and won't turn off the backlight
2390 when using the X Window system. This also doesn't have anything to
2391 do with your VESA-compliant power-saving monitor. Further, this
2392 option doesn't work for all laptops -- it might not turn off your
2393 backlight at all, or it might print a lot of errors to the console,
2394 especially if you are using gpm.
2395
2396 config APM_ALLOW_INTS
2397 bool "Allow interrupts during APM BIOS calls"
2398 ---help---
2399 Normally we disable external interrupts while we are making calls to
2400 the APM BIOS as a measure to lessen the effects of a badly behaving
2401 BIOS implementation. The BIOS should reenable interrupts if it
2402 needs to. Unfortunately, some BIOSes do not -- especially those in
2403 many of the newer IBM Thinkpads. If you experience hangs when you
2404 suspend, try setting this to Y. Otherwise, say N.
2405
2406 endif # APM
2407
2408 source "drivers/cpufreq/Kconfig"
2409
2410 source "drivers/cpuidle/Kconfig"
2411
2412 source "drivers/idle/Kconfig"
2413
2414 endmenu
2415
2416
2417 menu "Bus options (PCI etc.)"
2418
2419 config PCI
2420 bool "PCI support"
2421 default y
2422 ---help---
2423 Find out whether you have a PCI motherboard. PCI is the name of a
2424 bus system, i.e. the way the CPU talks to the other stuff inside
2425 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2426 VESA. If you have PCI, say Y, otherwise N.
2427
2428 choice
2429 prompt "PCI access mode"
2430 depends on X86_32 && PCI
2431 default PCI_GOANY
2432 ---help---
2433 On PCI systems, the BIOS can be used to detect the PCI devices and
2434 determine their configuration. However, some old PCI motherboards
2435 have BIOS bugs and may crash if this is done. Also, some embedded
2436 PCI-based systems don't have any BIOS at all. Linux can also try to
2437 detect the PCI hardware directly without using the BIOS.
2438
2439 With this option, you can specify how Linux should detect the
2440 PCI devices. If you choose "BIOS", the BIOS will be used,
2441 if you choose "Direct", the BIOS won't be used, and if you
2442 choose "MMConfig", then PCI Express MMCONFIG will be used.
2443 If you choose "Any", the kernel will try MMCONFIG, then the
2444 direct access method and falls back to the BIOS if that doesn't
2445 work. If unsure, go with the default, which is "Any".
2446
2447 config PCI_GOBIOS
2448 bool "BIOS"
2449
2450 config PCI_GOMMCONFIG
2451 bool "MMConfig"
2452
2453 config PCI_GODIRECT
2454 bool "Direct"
2455
2456 config PCI_GOOLPC
2457 bool "OLPC XO-1"
2458 depends on OLPC
2459
2460 config PCI_GOANY
2461 bool "Any"
2462
2463 endchoice
2464
2465 config PCI_BIOS
2466 def_bool y
2467 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2468
2469 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2470 config PCI_DIRECT
2471 def_bool y
2472 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2473
2474 config PCI_MMCONFIG
2475 def_bool y
2476 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2477
2478 config PCI_OLPC
2479 def_bool y
2480 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2481
2482 config PCI_XEN
2483 def_bool y
2484 depends on PCI && XEN
2485 select SWIOTLB_XEN
2486
2487 config PCI_DOMAINS
2488 def_bool y
2489 depends on PCI
2490
2491 config PCI_MMCONFIG
2492 bool "Support mmconfig PCI config space access"
2493 depends on X86_64 && PCI && ACPI
2494
2495 config PCI_CNB20LE_QUIRK
2496 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2497 depends on PCI
2498 help
2499 Read the PCI windows out of the CNB20LE host bridge. This allows
2500 PCI hotplug to work on systems with the CNB20LE chipset which do
2501 not have ACPI.
2502
2503 There's no public spec for this chipset, and this functionality
2504 is known to be incomplete.
2505
2506 You should say N unless you know you need this.
2507
2508 source "drivers/pci/Kconfig"
2509
2510 config ISA_BUS
2511 bool "ISA-style bus support on modern systems" if EXPERT
2512 select ISA_BUS_API
2513 help
2514 Enables ISA-style drivers on modern systems. This is necessary to
2515 support PC/104 devices on X86_64 platforms.
2516
2517 If unsure, say N.
2518
2519 # x86_64 have no ISA slots, but can have ISA-style DMA.
2520 config ISA_DMA_API
2521 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2522 default y
2523 help
2524 Enables ISA-style DMA support for devices requiring such controllers.
2525 If unsure, say Y.
2526
2527 if X86_32
2528
2529 config ISA
2530 bool "ISA support"
2531 ---help---
2532 Find out whether you have ISA slots on your motherboard. ISA is the
2533 name of a bus system, i.e. the way the CPU talks to the other stuff
2534 inside your box. Other bus systems are PCI, EISA, MicroChannel
2535 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2536 newer boards don't support it. If you have ISA, say Y, otherwise N.
2537
2538 config EISA
2539 bool "EISA support"
2540 depends on ISA
2541 ---help---
2542 The Extended Industry Standard Architecture (EISA) bus was
2543 developed as an open alternative to the IBM MicroChannel bus.
2544
2545 The EISA bus provided some of the features of the IBM MicroChannel
2546 bus while maintaining backward compatibility with cards made for
2547 the older ISA bus. The EISA bus saw limited use between 1988 and
2548 1995 when it was made obsolete by the PCI bus.
2549
2550 Say Y here if you are building a kernel for an EISA-based machine.
2551
2552 Otherwise, say N.
2553
2554 source "drivers/eisa/Kconfig"
2555
2556 config SCx200
2557 tristate "NatSemi SCx200 support"
2558 ---help---
2559 This provides basic support for National Semiconductor's
2560 (now AMD's) Geode processors. The driver probes for the
2561 PCI-IDs of several on-chip devices, so its a good dependency
2562 for other scx200_* drivers.
2563
2564 If compiled as a module, the driver is named scx200.
2565
2566 config SCx200HR_TIMER
2567 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2568 depends on SCx200
2569 default y
2570 ---help---
2571 This driver provides a clocksource built upon the on-chip
2572 27MHz high-resolution timer. Its also a workaround for
2573 NSC Geode SC-1100's buggy TSC, which loses time when the
2574 processor goes idle (as is done by the scheduler). The
2575 other workaround is idle=poll boot option.
2576
2577 config OLPC
2578 bool "One Laptop Per Child support"
2579 depends on !X86_PAE
2580 select GPIOLIB
2581 select OF
2582 select OF_PROMTREE
2583 select IRQ_DOMAIN
2584 ---help---
2585 Add support for detecting the unique features of the OLPC
2586 XO hardware.
2587
2588 config OLPC_XO1_PM
2589 bool "OLPC XO-1 Power Management"
2590 depends on OLPC && MFD_CS5535 && PM_SLEEP
2591 select MFD_CORE
2592 ---help---
2593 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2594
2595 config OLPC_XO1_RTC
2596 bool "OLPC XO-1 Real Time Clock"
2597 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2598 ---help---
2599 Add support for the XO-1 real time clock, which can be used as a
2600 programmable wakeup source.
2601
2602 config OLPC_XO1_SCI
2603 bool "OLPC XO-1 SCI extras"
2604 depends on OLPC && OLPC_XO1_PM
2605 depends on INPUT=y
2606 select POWER_SUPPLY
2607 select GPIO_CS5535
2608 select MFD_CORE
2609 ---help---
2610 Add support for SCI-based features of the OLPC XO-1 laptop:
2611 - EC-driven system wakeups
2612 - Power button
2613 - Ebook switch
2614 - Lid switch
2615 - AC adapter status updates
2616 - Battery status updates
2617
2618 config OLPC_XO15_SCI
2619 bool "OLPC XO-1.5 SCI extras"
2620 depends on OLPC && ACPI
2621 select POWER_SUPPLY
2622 ---help---
2623 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2624 - EC-driven system wakeups
2625 - AC adapter status updates
2626 - Battery status updates
2627
2628 config ALIX
2629 bool "PCEngines ALIX System Support (LED setup)"
2630 select GPIOLIB
2631 ---help---
2632 This option enables system support for the PCEngines ALIX.
2633 At present this just sets up LEDs for GPIO control on
2634 ALIX2/3/6 boards. However, other system specific setup should
2635 get added here.
2636
2637 Note: You must still enable the drivers for GPIO and LED support
2638 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2639
2640 Note: You have to set alix.force=1 for boards with Award BIOS.
2641
2642 config NET5501
2643 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2644 select GPIOLIB
2645 ---help---
2646 This option enables system support for the Soekris Engineering net5501.
2647
2648 config GEOS
2649 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2650 select GPIOLIB
2651 depends on DMI
2652 ---help---
2653 This option enables system support for the Traverse Technologies GEOS.
2654
2655 config TS5500
2656 bool "Technologic Systems TS-5500 platform support"
2657 depends on MELAN
2658 select CHECK_SIGNATURE
2659 select NEW_LEDS
2660 select LEDS_CLASS
2661 ---help---
2662 This option enables system support for the Technologic Systems TS-5500.
2663
2664 endif # X86_32
2665
2666 config AMD_NB
2667 def_bool y
2668 depends on CPU_SUP_AMD && PCI
2669
2670 source "drivers/pcmcia/Kconfig"
2671
2672 config RAPIDIO
2673 tristate "RapidIO support"
2674 depends on PCI
2675 default n
2676 help
2677 If enabled this option will include drivers and the core
2678 infrastructure code to support RapidIO interconnect devices.
2679
2680 source "drivers/rapidio/Kconfig"
2681
2682 config X86_SYSFB
2683 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2684 help
2685 Firmwares often provide initial graphics framebuffers so the BIOS,
2686 bootloader or kernel can show basic video-output during boot for
2687 user-guidance and debugging. Historically, x86 used the VESA BIOS
2688 Extensions and EFI-framebuffers for this, which are mostly limited
2689 to x86.
2690 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2691 framebuffers so the new generic system-framebuffer drivers can be
2692 used on x86. If the framebuffer is not compatible with the generic
2693 modes, it is adverticed as fallback platform framebuffer so legacy
2694 drivers like efifb, vesafb and uvesafb can pick it up.
2695 If this option is not selected, all system framebuffers are always
2696 marked as fallback platform framebuffers as usual.
2697
2698 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2699 not be able to pick up generic system framebuffers if this option
2700 is selected. You are highly encouraged to enable simplefb as
2701 replacement if you select this option. simplefb can correctly deal
2702 with generic system framebuffers. But you should still keep vesafb
2703 and others enabled as fallback if a system framebuffer is
2704 incompatible with simplefb.
2705
2706 If unsure, say Y.
2707
2708 endmenu
2709
2710
2711 menu "Executable file formats / Emulations"
2712
2713 source "fs/Kconfig.binfmt"
2714
2715 config IA32_EMULATION
2716 bool "IA32 Emulation"
2717 depends on X86_64
2718 select BINFMT_ELF
2719 select COMPAT_BINFMT_ELF
2720 select ARCH_WANT_OLD_COMPAT_IPC
2721 ---help---
2722 Include code to run legacy 32-bit programs under a
2723 64-bit kernel. You should likely turn this on, unless you're
2724 100% sure that you don't have any 32-bit programs left.
2725
2726 config IA32_AOUT
2727 tristate "IA32 a.out support"
2728 depends on IA32_EMULATION
2729 ---help---
2730 Support old a.out binaries in the 32bit emulation.
2731
2732 config X86_X32
2733 bool "x32 ABI for 64-bit mode"
2734 depends on X86_64
2735 ---help---
2736 Include code to run binaries for the x32 native 32-bit ABI
2737 for 64-bit processors. An x32 process gets access to the
2738 full 64-bit register file and wide data path while leaving
2739 pointers at 32 bits for smaller memory footprint.
2740
2741 You will need a recent binutils (2.22 or later) with
2742 elf32_x86_64 support enabled to compile a kernel with this
2743 option set.
2744
2745 config COMPAT
2746 def_bool y
2747 depends on IA32_EMULATION || X86_X32
2748
2749 if COMPAT
2750 config COMPAT_FOR_U64_ALIGNMENT
2751 def_bool y
2752
2753 config SYSVIPC_COMPAT
2754 def_bool y
2755 depends on SYSVIPC
2756
2757 config KEYS_COMPAT
2758 def_bool y
2759 depends on KEYS
2760 endif
2761
2762 endmenu
2763
2764
2765 config HAVE_ATOMIC_IOMAP
2766 def_bool y
2767 depends on X86_32
2768
2769 config X86_DEV_DMA_OPS
2770 bool
2771 depends on X86_64 || STA2X11
2772
2773 config X86_DMA_REMAP
2774 bool
2775 depends on STA2X11
2776
2777 config PMC_ATOM
2778 def_bool y
2779 depends on PCI
2780
2781 source "net/Kconfig"
2782
2783 source "drivers/Kconfig"
2784
2785 source "drivers/firmware/Kconfig"
2786
2787 source "fs/Kconfig"
2788
2789 source "arch/x86/Kconfig.debug"
2790
2791 source "security/Kconfig"
2792
2793 source "crypto/Kconfig"
2794
2795 source "arch/x86/kvm/Kconfig"
2796
2797 source "lib/Kconfig"