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1 # SPDX-License-Identifier: GPL-2.0
2 # Select 32 or 64 bit
3 config 64BIT
4 bool "64-bit kernel" if ARCH = "x86"
5 default ARCH != "i386"
6 ---help---
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
9
10 config X86_32
11 def_bool y
12 depends on !64BIT
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
15 select CLKSRC_I8253
16 select CLONE_BACKWARDS
17 select HAVE_AOUT
18 select HAVE_GENERIC_DMA_COHERENT
19 select MODULES_USE_ELF_REL
20 select OLD_SIGACTION
21
22 config X86_64
23 def_bool y
24 depends on 64BIT
25 # Options that are inherently 64-bit kernel only:
26 select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
27 select ARCH_SUPPORTS_INT128
28 select ARCH_USE_CMPXCHG_LOCKREF
29 select HAVE_ARCH_SOFT_DIRTY
30 select MODULES_USE_ELF_RELA
31 select X86_DEV_DMA_OPS
32
33 #
34 # Arch settings
35 #
36 # ( Note that options that are marked 'if X86_64' could in principle be
37 # ported to 32-bit as well. )
38 #
39 config X86
40 def_bool y
41 #
42 # Note: keep this list sorted alphabetically
43 #
44 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
45 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
46 select ANON_INODES
47 select ARCH_CLOCKSOURCE_DATA
48 select ARCH_DISCARD_MEMBLOCK
49 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
50 select ARCH_HAS_DEBUG_VIRTUAL
51 select ARCH_HAS_DEVMEM_IS_ALLOWED
52 select ARCH_HAS_ELF_RANDOMIZE
53 select ARCH_HAS_FAST_MULTIPLIER
54 select ARCH_HAS_FORTIFY_SOURCE
55 select ARCH_HAS_GCOV_PROFILE_ALL
56 select ARCH_HAS_KCOV if X86_64
57 select ARCH_HAS_PMEM_API if X86_64
58 # Causing hangs/crashes, see the commit that added this change for details.
59 select ARCH_HAS_REFCOUNT
60 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
61 select ARCH_HAS_SET_MEMORY
62 select ARCH_HAS_SG_CHAIN
63 select ARCH_HAS_STRICT_KERNEL_RWX
64 select ARCH_HAS_STRICT_MODULE_RWX
65 select ARCH_HAS_UBSAN_SANITIZE_ALL
66 select ARCH_HAS_ZONE_DEVICE if X86_64
67 select ARCH_HAVE_NMI_SAFE_CMPXCHG
68 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
69 select ARCH_MIGHT_HAVE_PC_PARPORT
70 select ARCH_MIGHT_HAVE_PC_SERIO
71 select ARCH_SUPPORTS_ATOMIC_RMW
72 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
73 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
74 select ARCH_USE_BUILTIN_BSWAP
75 select ARCH_USE_QUEUED_RWLOCKS
76 select ARCH_USE_QUEUED_SPINLOCKS
77 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
78 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
79 select ARCH_WANTS_THP_SWAP if X86_64
80 select BUILDTIME_EXTABLE_SORT
81 select CLKEVT_I8253
82 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
83 select CLOCKSOURCE_WATCHDOG
84 select DCACHE_WORD_ACCESS
85 select EDAC_ATOMIC_SCRUB
86 select EDAC_SUPPORT
87 select GENERIC_CLOCKEVENTS
88 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
89 select GENERIC_CLOCKEVENTS_MIN_ADJUST
90 select GENERIC_CMOS_UPDATE
91 select GENERIC_CPU_AUTOPROBE
92 select GENERIC_EARLY_IOREMAP
93 select GENERIC_FIND_FIRST_BIT
94 select GENERIC_IOMAP
95 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
96 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
97 select GENERIC_IRQ_MIGRATION if SMP
98 select GENERIC_IRQ_PROBE
99 select GENERIC_IRQ_RESERVATION_MODE
100 select GENERIC_IRQ_SHOW
101 select GENERIC_PENDING_IRQ if SMP
102 select GENERIC_SMP_IDLE_THREAD
103 select GENERIC_STRNCPY_FROM_USER
104 select GENERIC_STRNLEN_USER
105 select GENERIC_TIME_VSYSCALL
106 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
107 select HAVE_ACPI_APEI if ACPI
108 select HAVE_ACPI_APEI_NMI if ACPI
109 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
110 select HAVE_ARCH_AUDITSYSCALL
111 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
112 select HAVE_ARCH_JUMP_LABEL
113 select HAVE_ARCH_KASAN if X86_64
114 select HAVE_ARCH_KGDB
115 select HAVE_ARCH_MMAP_RND_BITS if MMU
116 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
117 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
118 select HAVE_ARCH_SECCOMP_FILTER
119 select HAVE_ARCH_TRACEHOOK
120 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
121 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
122 select HAVE_ARCH_VMAP_STACK if X86_64
123 select HAVE_ARCH_WITHIN_STACK_FRAMES
124 select HAVE_CC_STACKPROTECTOR
125 select HAVE_CMPXCHG_DOUBLE
126 select HAVE_CMPXCHG_LOCAL
127 select HAVE_CONTEXT_TRACKING if X86_64
128 select HAVE_COPY_THREAD_TLS
129 select HAVE_C_RECORDMCOUNT
130 select HAVE_DEBUG_KMEMLEAK
131 select HAVE_DEBUG_STACKOVERFLOW
132 select HAVE_DMA_API_DEBUG
133 select HAVE_DMA_CONTIGUOUS
134 select HAVE_DYNAMIC_FTRACE
135 select HAVE_DYNAMIC_FTRACE_WITH_REGS
136 select HAVE_EBPF_JIT if X86_64
137 select HAVE_EFFICIENT_UNALIGNED_ACCESS
138 select HAVE_EXIT_THREAD
139 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
140 select HAVE_FTRACE_MCOUNT_RECORD
141 select HAVE_FUNCTION_GRAPH_TRACER
142 select HAVE_FUNCTION_TRACER
143 select HAVE_GCC_PLUGINS
144 select HAVE_HW_BREAKPOINT
145 select HAVE_IDE
146 select HAVE_IOREMAP_PROT
147 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
148 select HAVE_IRQ_TIME_ACCOUNTING
149 select HAVE_KERNEL_BZIP2
150 select HAVE_KERNEL_GZIP
151 select HAVE_KERNEL_LZ4
152 select HAVE_KERNEL_LZMA
153 select HAVE_KERNEL_LZO
154 select HAVE_KERNEL_XZ
155 select HAVE_KPROBES
156 select HAVE_KPROBES_ON_FTRACE
157 select HAVE_KRETPROBES
158 select HAVE_KVM
159 select HAVE_LIVEPATCH if X86_64
160 select HAVE_MEMBLOCK
161 select HAVE_MEMBLOCK_NODE_MAP
162 select HAVE_MIXED_BREAKPOINTS_REGS
163 select HAVE_MOD_ARCH_SPECIFIC
164 select HAVE_NMI
165 select HAVE_OPROFILE
166 select HAVE_OPTPROBES
167 select HAVE_PCSPKR_PLATFORM
168 select HAVE_PERF_EVENTS
169 select HAVE_PERF_EVENTS_NMI
170 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
171 select HAVE_PERF_REGS
172 select HAVE_PERF_USER_STACK_DUMP
173 select HAVE_RCU_TABLE_FREE
174 select HAVE_REGS_AND_STACK_ACCESS_API
175 select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION
176 select HAVE_STACK_VALIDATION if X86_64
177 select HAVE_SYSCALL_TRACEPOINTS
178 select HAVE_UNSTABLE_SCHED_CLOCK
179 select HAVE_USER_RETURN_NOTIFIER
180 select IRQ_FORCED_THREADING
181 select PCI_LOCKLESS_CONFIG
182 select PERF_EVENTS
183 select RTC_LIB
184 select RTC_MC146818_LIB
185 select SPARSE_IRQ
186 select SRCU
187 select SYSCTL_EXCEPTION_TRACE
188 select THREAD_INFO_IN_TASK
189 select USER_STACKTRACE_SUPPORT
190 select VIRT_TO_BUS
191 select X86_FEATURE_NAMES if PROC_FS
192
193 config INSTRUCTION_DECODER
194 def_bool y
195 depends on KPROBES || PERF_EVENTS || UPROBES
196
197 config OUTPUT_FORMAT
198 string
199 default "elf32-i386" if X86_32
200 default "elf64-x86-64" if X86_64
201
202 config ARCH_DEFCONFIG
203 string
204 default "arch/x86/configs/i386_defconfig" if X86_32
205 default "arch/x86/configs/x86_64_defconfig" if X86_64
206
207 config LOCKDEP_SUPPORT
208 def_bool y
209
210 config STACKTRACE_SUPPORT
211 def_bool y
212
213 config MMU
214 def_bool y
215
216 config ARCH_MMAP_RND_BITS_MIN
217 default 28 if 64BIT
218 default 8
219
220 config ARCH_MMAP_RND_BITS_MAX
221 default 32 if 64BIT
222 default 16
223
224 config ARCH_MMAP_RND_COMPAT_BITS_MIN
225 default 8
226
227 config ARCH_MMAP_RND_COMPAT_BITS_MAX
228 default 16
229
230 config SBUS
231 bool
232
233 config NEED_DMA_MAP_STATE
234 def_bool y
235 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
236
237 config NEED_SG_DMA_LENGTH
238 def_bool y
239
240 config GENERIC_ISA_DMA
241 def_bool y
242 depends on ISA_DMA_API
243
244 config GENERIC_BUG
245 def_bool y
246 depends on BUG
247 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
248
249 config GENERIC_BUG_RELATIVE_POINTERS
250 bool
251
252 config GENERIC_HWEIGHT
253 def_bool y
254
255 config ARCH_MAY_HAVE_PC_FDC
256 def_bool y
257 depends on ISA_DMA_API
258
259 config RWSEM_XCHGADD_ALGORITHM
260 def_bool y
261
262 config GENERIC_CALIBRATE_DELAY
263 def_bool y
264
265 config ARCH_HAS_CPU_RELAX
266 def_bool y
267
268 config ARCH_HAS_CACHE_LINE_SIZE
269 def_bool y
270
271 config HAVE_SETUP_PER_CPU_AREA
272 def_bool y
273
274 config NEED_PER_CPU_EMBED_FIRST_CHUNK
275 def_bool y
276
277 config NEED_PER_CPU_PAGE_FIRST_CHUNK
278 def_bool y
279
280 config ARCH_HIBERNATION_POSSIBLE
281 def_bool y
282
283 config ARCH_SUSPEND_POSSIBLE
284 def_bool y
285
286 config ARCH_WANT_HUGE_PMD_SHARE
287 def_bool y
288
289 config ARCH_WANT_GENERAL_HUGETLB
290 def_bool y
291
292 config ZONE_DMA32
293 def_bool y if X86_64
294
295 config AUDIT_ARCH
296 def_bool y if X86_64
297
298 config ARCH_SUPPORTS_OPTIMIZED_INLINING
299 def_bool y
300
301 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
302 def_bool y
303
304 config KASAN_SHADOW_OFFSET
305 hex
306 depends on KASAN
307 default 0xdffffc0000000000
308
309 config HAVE_INTEL_TXT
310 def_bool y
311 depends on INTEL_IOMMU && ACPI
312
313 config X86_32_SMP
314 def_bool y
315 depends on X86_32 && SMP
316
317 config X86_64_SMP
318 def_bool y
319 depends on X86_64 && SMP
320
321 config X86_32_LAZY_GS
322 def_bool y
323 depends on X86_32 && !CC_STACKPROTECTOR
324
325 config ARCH_SUPPORTS_UPROBES
326 def_bool y
327
328 config FIX_EARLYCON_MEM
329 def_bool y
330
331 config PGTABLE_LEVELS
332 int
333 default 5 if X86_5LEVEL
334 default 4 if X86_64
335 default 3 if X86_PAE
336 default 2
337
338 source "init/Kconfig"
339 source "kernel/Kconfig.freezer"
340
341 menu "Processor type and features"
342
343 config ZONE_DMA
344 bool "DMA memory allocation support" if EXPERT
345 default y
346 help
347 DMA memory allocation support allows devices with less than 32-bit
348 addressing to allocate within the first 16MB of address space.
349 Disable if no such devices will be used.
350
351 If unsure, say Y.
352
353 config SMP
354 bool "Symmetric multi-processing support"
355 ---help---
356 This enables support for systems with more than one CPU. If you have
357 a system with only one CPU, say N. If you have a system with more
358 than one CPU, say Y.
359
360 If you say N here, the kernel will run on uni- and multiprocessor
361 machines, but will use only one CPU of a multiprocessor machine. If
362 you say Y here, the kernel will run on many, but not all,
363 uniprocessor machines. On a uniprocessor machine, the kernel
364 will run faster if you say N here.
365
366 Note that if you say Y here and choose architecture "586" or
367 "Pentium" under "Processor family", the kernel will not work on 486
368 architectures. Similarly, multiprocessor kernels for the "PPro"
369 architecture may not work on all Pentium based boards.
370
371 People using multiprocessor machines who say Y here should also say
372 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
373 Management" code will be disabled if you say Y here.
374
375 See also <file:Documentation/x86/i386/IO-APIC.txt>,
376 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
377 <http://www.tldp.org/docs.html#howto>.
378
379 If you don't know what to do here, say N.
380
381 config X86_FEATURE_NAMES
382 bool "Processor feature human-readable names" if EMBEDDED
383 default y
384 ---help---
385 This option compiles in a table of x86 feature bits and corresponding
386 names. This is required to support /proc/cpuinfo and a few kernel
387 messages. You can disable this to save space, at the expense of
388 making those few kernel messages show numeric feature bits instead.
389
390 If in doubt, say Y.
391
392 config X86_FAST_FEATURE_TESTS
393 bool "Fast CPU feature tests" if EMBEDDED
394 default y
395 ---help---
396 Some fast-paths in the kernel depend on the capabilities of the CPU.
397 Say Y here for the kernel to patch in the appropriate code at runtime
398 based on the capabilities of the CPU. The infrastructure for patching
399 code at runtime takes up some additional space; space-constrained
400 embedded systems may wish to say N here to produce smaller, slightly
401 slower code.
402
403 config X86_X2APIC
404 bool "Support x2apic"
405 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
406 ---help---
407 This enables x2apic support on CPUs that have this feature.
408
409 This allows 32-bit apic IDs (so it can support very large systems),
410 and accesses the local apic via MSRs not via mmio.
411
412 If you don't know what to do here, say N.
413
414 config X86_MPPARSE
415 bool "Enable MPS table" if ACPI || SFI
416 default y
417 depends on X86_LOCAL_APIC
418 ---help---
419 For old smp systems that do not have proper acpi support. Newer systems
420 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
421
422 config X86_BIGSMP
423 bool "Support for big SMP systems with more than 8 CPUs"
424 depends on X86_32 && SMP
425 ---help---
426 This option is needed for the systems that have more than 8 CPUs
427
428 config GOLDFISH
429 def_bool y
430 depends on X86_GOLDFISH
431
432 config INTEL_RDT
433 bool "Intel Resource Director Technology support"
434 default n
435 depends on X86 && CPU_SUP_INTEL
436 select KERNFS
437 help
438 Select to enable resource allocation and monitoring which are
439 sub-features of Intel Resource Director Technology(RDT). More
440 information about RDT can be found in the Intel x86
441 Architecture Software Developer Manual.
442
443 Say N if unsure.
444
445 if X86_32
446 config X86_EXTENDED_PLATFORM
447 bool "Support for extended (non-PC) x86 platforms"
448 default y
449 ---help---
450 If you disable this option then the kernel will only support
451 standard PC platforms. (which covers the vast majority of
452 systems out there.)
453
454 If you enable this option then you'll be able to select support
455 for the following (non-PC) 32 bit x86 platforms:
456 Goldfish (Android emulator)
457 AMD Elan
458 RDC R-321x SoC
459 SGI 320/540 (Visual Workstation)
460 STA2X11-based (e.g. Northville)
461 Moorestown MID devices
462
463 If you have one of these systems, or if you want to build a
464 generic distribution kernel, say Y here - otherwise say N.
465 endif
466
467 if X86_64
468 config X86_EXTENDED_PLATFORM
469 bool "Support for extended (non-PC) x86 platforms"
470 default y
471 ---help---
472 If you disable this option then the kernel will only support
473 standard PC platforms. (which covers the vast majority of
474 systems out there.)
475
476 If you enable this option then you'll be able to select support
477 for the following (non-PC) 64 bit x86 platforms:
478 Numascale NumaChip
479 ScaleMP vSMP
480 SGI Ultraviolet
481
482 If you have one of these systems, or if you want to build a
483 generic distribution kernel, say Y here - otherwise say N.
484 endif
485 # This is an alphabetically sorted list of 64 bit extended platforms
486 # Please maintain the alphabetic order if and when there are additions
487 config X86_NUMACHIP
488 bool "Numascale NumaChip"
489 depends on X86_64
490 depends on X86_EXTENDED_PLATFORM
491 depends on NUMA
492 depends on SMP
493 depends on X86_X2APIC
494 depends on PCI_MMCONFIG
495 ---help---
496 Adds support for Numascale NumaChip large-SMP systems. Needed to
497 enable more than ~168 cores.
498 If you don't have one of these, you should say N here.
499
500 config X86_VSMP
501 bool "ScaleMP vSMP"
502 select HYPERVISOR_GUEST
503 select PARAVIRT
504 depends on X86_64 && PCI
505 depends on X86_EXTENDED_PLATFORM
506 depends on SMP
507 ---help---
508 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
509 supposed to run on these EM64T-based machines. Only choose this option
510 if you have one of these machines.
511
512 config X86_UV
513 bool "SGI Ultraviolet"
514 depends on X86_64
515 depends on X86_EXTENDED_PLATFORM
516 depends on NUMA
517 depends on EFI
518 depends on X86_X2APIC
519 depends on PCI
520 ---help---
521 This option is needed in order to support SGI Ultraviolet systems.
522 If you don't have one of these, you should say N here.
523
524 # Following is an alphabetically sorted list of 32 bit extended platforms
525 # Please maintain the alphabetic order if and when there are additions
526
527 config X86_GOLDFISH
528 bool "Goldfish (Virtual Platform)"
529 depends on X86_EXTENDED_PLATFORM
530 ---help---
531 Enable support for the Goldfish virtual platform used primarily
532 for Android development. Unless you are building for the Android
533 Goldfish emulator say N here.
534
535 config X86_INTEL_CE
536 bool "CE4100 TV platform"
537 depends on PCI
538 depends on PCI_GODIRECT
539 depends on X86_IO_APIC
540 depends on X86_32
541 depends on X86_EXTENDED_PLATFORM
542 select X86_REBOOTFIXUPS
543 select OF
544 select OF_EARLY_FLATTREE
545 ---help---
546 Select for the Intel CE media processor (CE4100) SOC.
547 This option compiles in support for the CE4100 SOC for settop
548 boxes and media devices.
549
550 config X86_INTEL_MID
551 bool "Intel MID platform support"
552 depends on X86_EXTENDED_PLATFORM
553 depends on X86_PLATFORM_DEVICES
554 depends on PCI
555 depends on X86_64 || (PCI_GOANY && X86_32)
556 depends on X86_IO_APIC
557 select SFI
558 select I2C
559 select DW_APB_TIMER
560 select APB_TIMER
561 select INTEL_SCU_IPC
562 select MFD_INTEL_MSIC
563 ---help---
564 Select to build a kernel capable of supporting Intel MID (Mobile
565 Internet Device) platform systems which do not have the PCI legacy
566 interfaces. If you are building for a PC class system say N here.
567
568 Intel MID platforms are based on an Intel processor and chipset which
569 consume less power than most of the x86 derivatives.
570
571 config X86_INTEL_QUARK
572 bool "Intel Quark platform support"
573 depends on X86_32
574 depends on X86_EXTENDED_PLATFORM
575 depends on X86_PLATFORM_DEVICES
576 depends on X86_TSC
577 depends on PCI
578 depends on PCI_GOANY
579 depends on X86_IO_APIC
580 select IOSF_MBI
581 select INTEL_IMR
582 select COMMON_CLK
583 ---help---
584 Select to include support for Quark X1000 SoC.
585 Say Y here if you have a Quark based system such as the Arduino
586 compatible Intel Galileo.
587
588 config X86_INTEL_LPSS
589 bool "Intel Low Power Subsystem Support"
590 depends on X86 && ACPI
591 select COMMON_CLK
592 select PINCTRL
593 select IOSF_MBI
594 ---help---
595 Select to build support for Intel Low Power Subsystem such as
596 found on Intel Lynxpoint PCH. Selecting this option enables
597 things like clock tree (common clock framework) and pincontrol
598 which are needed by the LPSS peripheral drivers.
599
600 config X86_AMD_PLATFORM_DEVICE
601 bool "AMD ACPI2Platform devices support"
602 depends on ACPI
603 select COMMON_CLK
604 select PINCTRL
605 ---help---
606 Select to interpret AMD specific ACPI device to platform device
607 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
608 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
609 implemented under PINCTRL subsystem.
610
611 config IOSF_MBI
612 tristate "Intel SoC IOSF Sideband support for SoC platforms"
613 depends on PCI
614 ---help---
615 This option enables sideband register access support for Intel SoC
616 platforms. On these platforms the IOSF sideband is used in lieu of
617 MSR's for some register accesses, mostly but not limited to thermal
618 and power. Drivers may query the availability of this device to
619 determine if they need the sideband in order to work on these
620 platforms. The sideband is available on the following SoC products.
621 This list is not meant to be exclusive.
622 - BayTrail
623 - Braswell
624 - Quark
625
626 You should say Y if you are running a kernel on one of these SoC's.
627
628 config IOSF_MBI_DEBUG
629 bool "Enable IOSF sideband access through debugfs"
630 depends on IOSF_MBI && DEBUG_FS
631 ---help---
632 Select this option to expose the IOSF sideband access registers (MCR,
633 MDR, MCRX) through debugfs to write and read register information from
634 different units on the SoC. This is most useful for obtaining device
635 state information for debug and analysis. As this is a general access
636 mechanism, users of this option would have specific knowledge of the
637 device they want to access.
638
639 If you don't require the option or are in doubt, say N.
640
641 config X86_RDC321X
642 bool "RDC R-321x SoC"
643 depends on X86_32
644 depends on X86_EXTENDED_PLATFORM
645 select M486
646 select X86_REBOOTFIXUPS
647 ---help---
648 This option is needed for RDC R-321x system-on-chip, also known
649 as R-8610-(G).
650 If you don't have one of these chips, you should say N here.
651
652 config X86_32_NON_STANDARD
653 bool "Support non-standard 32-bit SMP architectures"
654 depends on X86_32 && SMP
655 depends on X86_EXTENDED_PLATFORM
656 ---help---
657 This option compiles in the bigsmp and STA2X11 default
658 subarchitectures. It is intended for a generic binary
659 kernel. If you select them all, kernel will probe it one by
660 one and will fallback to default.
661
662 # Alphabetically sorted list of Non standard 32 bit platforms
663
664 config X86_SUPPORTS_MEMORY_FAILURE
665 def_bool y
666 # MCE code calls memory_failure():
667 depends on X86_MCE
668 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
669 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
670 depends on X86_64 || !SPARSEMEM
671 select ARCH_SUPPORTS_MEMORY_FAILURE
672
673 config STA2X11
674 bool "STA2X11 Companion Chip Support"
675 depends on X86_32_NON_STANDARD && PCI
676 select X86_DEV_DMA_OPS
677 select X86_DMA_REMAP
678 select SWIOTLB
679 select MFD_STA2X11
680 select GPIOLIB
681 default n
682 ---help---
683 This adds support for boards based on the STA2X11 IO-Hub,
684 a.k.a. "ConneXt". The chip is used in place of the standard
685 PC chipset, so all "standard" peripherals are missing. If this
686 option is selected the kernel will still be able to boot on
687 standard PC machines.
688
689 config X86_32_IRIS
690 tristate "Eurobraille/Iris poweroff module"
691 depends on X86_32
692 ---help---
693 The Iris machines from EuroBraille do not have APM or ACPI support
694 to shut themselves down properly. A special I/O sequence is
695 needed to do so, which is what this module does at
696 kernel shutdown.
697
698 This is only for Iris machines from EuroBraille.
699
700 If unused, say N.
701
702 config SCHED_OMIT_FRAME_POINTER
703 def_bool y
704 prompt "Single-depth WCHAN output"
705 depends on X86
706 ---help---
707 Calculate simpler /proc/<PID>/wchan values. If this option
708 is disabled then wchan values will recurse back to the
709 caller function. This provides more accurate wchan values,
710 at the expense of slightly more scheduling overhead.
711
712 If in doubt, say "Y".
713
714 menuconfig HYPERVISOR_GUEST
715 bool "Linux guest support"
716 ---help---
717 Say Y here to enable options for running Linux under various hyper-
718 visors. This option enables basic hypervisor detection and platform
719 setup.
720
721 If you say N, all options in this submenu will be skipped and
722 disabled, and Linux guest support won't be built in.
723
724 if HYPERVISOR_GUEST
725
726 config PARAVIRT
727 bool "Enable paravirtualization code"
728 ---help---
729 This changes the kernel so it can modify itself when it is run
730 under a hypervisor, potentially improving performance significantly
731 over full virtualization. However, when run without a hypervisor
732 the kernel is theoretically slower and slightly larger.
733
734 config PARAVIRT_DEBUG
735 bool "paravirt-ops debugging"
736 depends on PARAVIRT && DEBUG_KERNEL
737 ---help---
738 Enable to debug paravirt_ops internals. Specifically, BUG if
739 a paravirt_op is missing when it is called.
740
741 config PARAVIRT_SPINLOCKS
742 bool "Paravirtualization layer for spinlocks"
743 depends on PARAVIRT && SMP
744 ---help---
745 Paravirtualized spinlocks allow a pvops backend to replace the
746 spinlock implementation with something virtualization-friendly
747 (for example, block the virtual CPU rather than spinning).
748
749 It has a minimal impact on native kernels and gives a nice performance
750 benefit on paravirtualized KVM / Xen kernels.
751
752 If you are unsure how to answer this question, answer Y.
753
754 config QUEUED_LOCK_STAT
755 bool "Paravirt queued spinlock statistics"
756 depends on PARAVIRT_SPINLOCKS && DEBUG_FS
757 ---help---
758 Enable the collection of statistical data on the slowpath
759 behavior of paravirtualized queued spinlocks and report
760 them on debugfs.
761
762 source "arch/x86/xen/Kconfig"
763
764 config KVM_GUEST
765 bool "KVM Guest support (including kvmclock)"
766 depends on PARAVIRT
767 select PARAVIRT_CLOCK
768 default y
769 ---help---
770 This option enables various optimizations for running under the KVM
771 hypervisor. It includes a paravirtualized clock, so that instead
772 of relying on a PIT (or probably other) emulation by the
773 underlying device model, the host provides the guest with
774 timing infrastructure such as time of day, and system time
775
776 config KVM_DEBUG_FS
777 bool "Enable debug information for KVM Guests in debugfs"
778 depends on KVM_GUEST && DEBUG_FS
779 default n
780 ---help---
781 This option enables collection of various statistics for KVM guest.
782 Statistics are displayed in debugfs filesystem. Enabling this option
783 may incur significant overhead.
784
785 config PARAVIRT_TIME_ACCOUNTING
786 bool "Paravirtual steal time accounting"
787 depends on PARAVIRT
788 default n
789 ---help---
790 Select this option to enable fine granularity task steal time
791 accounting. Time spent executing other tasks in parallel with
792 the current vCPU is discounted from the vCPU power. To account for
793 that, there can be a small performance impact.
794
795 If in doubt, say N here.
796
797 config PARAVIRT_CLOCK
798 bool
799
800 endif #HYPERVISOR_GUEST
801
802 config NO_BOOTMEM
803 def_bool y
804
805 source "arch/x86/Kconfig.cpu"
806
807 config HPET_TIMER
808 def_bool X86_64
809 prompt "HPET Timer Support" if X86_32
810 ---help---
811 Use the IA-PC HPET (High Precision Event Timer) to manage
812 time in preference to the PIT and RTC, if a HPET is
813 present.
814 HPET is the next generation timer replacing legacy 8254s.
815 The HPET provides a stable time base on SMP
816 systems, unlike the TSC, but it is more expensive to access,
817 as it is off-chip. The interface used is documented
818 in the HPET spec, revision 1.
819
820 You can safely choose Y here. However, HPET will only be
821 activated if the platform and the BIOS support this feature.
822 Otherwise the 8254 will be used for timing services.
823
824 Choose N to continue using the legacy 8254 timer.
825
826 config HPET_EMULATE_RTC
827 def_bool y
828 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
829
830 config APB_TIMER
831 def_bool y if X86_INTEL_MID
832 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
833 select DW_APB_TIMER
834 depends on X86_INTEL_MID && SFI
835 help
836 APB timer is the replacement for 8254, HPET on X86 MID platforms.
837 The APBT provides a stable time base on SMP
838 systems, unlike the TSC, but it is more expensive to access,
839 as it is off-chip. APB timers are always running regardless of CPU
840 C states, they are used as per CPU clockevent device when possible.
841
842 # Mark as expert because too many people got it wrong.
843 # The code disables itself when not needed.
844 config DMI
845 default y
846 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
847 bool "Enable DMI scanning" if EXPERT
848 ---help---
849 Enabled scanning of DMI to identify machine quirks. Say Y
850 here unless you have verified that your setup is not
851 affected by entries in the DMI blacklist. Required by PNP
852 BIOS code.
853
854 config GART_IOMMU
855 bool "Old AMD GART IOMMU support"
856 select SWIOTLB
857 depends on X86_64 && PCI && AMD_NB
858 ---help---
859 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
860 GART based hardware IOMMUs.
861
862 The GART supports full DMA access for devices with 32-bit access
863 limitations, on systems with more than 3 GB. This is usually needed
864 for USB, sound, many IDE/SATA chipsets and some other devices.
865
866 Newer systems typically have a modern AMD IOMMU, supported via
867 the CONFIG_AMD_IOMMU=y config option.
868
869 In normal configurations this driver is only active when needed:
870 there's more than 3 GB of memory and the system contains a
871 32-bit limited device.
872
873 If unsure, say Y.
874
875 config CALGARY_IOMMU
876 bool "IBM Calgary IOMMU support"
877 select SWIOTLB
878 depends on X86_64 && PCI
879 ---help---
880 Support for hardware IOMMUs in IBM's xSeries x366 and x460
881 systems. Needed to run systems with more than 3GB of memory
882 properly with 32-bit PCI devices that do not support DAC
883 (Double Address Cycle). Calgary also supports bus level
884 isolation, where all DMAs pass through the IOMMU. This
885 prevents them from going anywhere except their intended
886 destination. This catches hard-to-find kernel bugs and
887 mis-behaving drivers and devices that do not use the DMA-API
888 properly to set up their DMA buffers. The IOMMU can be
889 turned off at boot time with the iommu=off parameter.
890 Normally the kernel will make the right choice by itself.
891 If unsure, say Y.
892
893 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
894 def_bool y
895 prompt "Should Calgary be enabled by default?"
896 depends on CALGARY_IOMMU
897 ---help---
898 Should Calgary be enabled by default? if you choose 'y', Calgary
899 will be used (if it exists). If you choose 'n', Calgary will not be
900 used even if it exists. If you choose 'n' and would like to use
901 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
902 If unsure, say Y.
903
904 # need this always selected by IOMMU for the VIA workaround
905 config SWIOTLB
906 def_bool y if X86_64
907 ---help---
908 Support for software bounce buffers used on x86-64 systems
909 which don't have a hardware IOMMU. Using this PCI devices
910 which can only access 32-bits of memory can be used on systems
911 with more than 3 GB of memory.
912 If unsure, say Y.
913
914 config IOMMU_HELPER
915 def_bool y
916 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
917
918 config MAXSMP
919 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
920 depends on X86_64 && SMP && DEBUG_KERNEL
921 select CPUMASK_OFFSTACK
922 ---help---
923 Enable maximum number of CPUS and NUMA Nodes for this architecture.
924 If unsure, say N.
925
926 config NR_CPUS
927 int "Maximum number of CPUs" if SMP && !MAXSMP
928 range 2 8 if SMP && X86_32 && !X86_BIGSMP
929 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
930 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
931 default "1" if !SMP
932 default "8192" if MAXSMP
933 default "32" if SMP && X86_BIGSMP
934 default "8" if SMP && X86_32
935 default "64" if SMP
936 ---help---
937 This allows you to specify the maximum number of CPUs which this
938 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
939 supported value is 8192, otherwise the maximum value is 512. The
940 minimum value which makes sense is 2.
941
942 This is purely to save memory - each supported CPU adds
943 approximately eight kilobytes to the kernel image.
944
945 config SCHED_SMT
946 bool "SMT (Hyperthreading) scheduler support"
947 depends on SMP
948 ---help---
949 SMT scheduler support improves the CPU scheduler's decision making
950 when dealing with Intel Pentium 4 chips with HyperThreading at a
951 cost of slightly increased overhead in some places. If unsure say
952 N here.
953
954 config SCHED_MC
955 def_bool y
956 prompt "Multi-core scheduler support"
957 depends on SMP
958 ---help---
959 Multi-core scheduler support improves the CPU scheduler's decision
960 making when dealing with multi-core CPU chips at a cost of slightly
961 increased overhead in some places. If unsure say N here.
962
963 config SCHED_MC_PRIO
964 bool "CPU core priorities scheduler support"
965 depends on SCHED_MC && CPU_SUP_INTEL
966 select X86_INTEL_PSTATE
967 select CPU_FREQ
968 default y
969 ---help---
970 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
971 core ordering determined at manufacturing time, which allows
972 certain cores to reach higher turbo frequencies (when running
973 single threaded workloads) than others.
974
975 Enabling this kernel feature teaches the scheduler about
976 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
977 scheduler's CPU selection logic accordingly, so that higher
978 overall system performance can be achieved.
979
980 This feature will have no effect on CPUs without this feature.
981
982 If unsure say Y here.
983
984 source "kernel/Kconfig.preempt"
985
986 config UP_LATE_INIT
987 def_bool y
988 depends on !SMP && X86_LOCAL_APIC
989
990 config X86_UP_APIC
991 bool "Local APIC support on uniprocessors" if !PCI_MSI
992 default PCI_MSI
993 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
994 ---help---
995 A local APIC (Advanced Programmable Interrupt Controller) is an
996 integrated interrupt controller in the CPU. If you have a single-CPU
997 system which has a processor with a local APIC, you can say Y here to
998 enable and use it. If you say Y here even though your machine doesn't
999 have a local APIC, then the kernel will still run with no slowdown at
1000 all. The local APIC supports CPU-generated self-interrupts (timer,
1001 performance counters), and the NMI watchdog which detects hard
1002 lockups.
1003
1004 config X86_UP_IOAPIC
1005 bool "IO-APIC support on uniprocessors"
1006 depends on X86_UP_APIC
1007 ---help---
1008 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1009 SMP-capable replacement for PC-style interrupt controllers. Most
1010 SMP systems and many recent uniprocessor systems have one.
1011
1012 If you have a single-CPU system with an IO-APIC, you can say Y here
1013 to use it. If you say Y here even though your machine doesn't have
1014 an IO-APIC, then the kernel will still run with no slowdown at all.
1015
1016 config X86_LOCAL_APIC
1017 def_bool y
1018 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1019 select IRQ_DOMAIN_HIERARCHY
1020 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1021
1022 config X86_IO_APIC
1023 def_bool y
1024 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1025
1026 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1027 bool "Reroute for broken boot IRQs"
1028 depends on X86_IO_APIC
1029 ---help---
1030 This option enables a workaround that fixes a source of
1031 spurious interrupts. This is recommended when threaded
1032 interrupt handling is used on systems where the generation of
1033 superfluous "boot interrupts" cannot be disabled.
1034
1035 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1036 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1037 kernel does during interrupt handling). On chipsets where this
1038 boot IRQ generation cannot be disabled, this workaround keeps
1039 the original IRQ line masked so that only the equivalent "boot
1040 IRQ" is delivered to the CPUs. The workaround also tells the
1041 kernel to set up the IRQ handler on the boot IRQ line. In this
1042 way only one interrupt is delivered to the kernel. Otherwise
1043 the spurious second interrupt may cause the kernel to bring
1044 down (vital) interrupt lines.
1045
1046 Only affects "broken" chipsets. Interrupt sharing may be
1047 increased on these systems.
1048
1049 config X86_MCE
1050 bool "Machine Check / overheating reporting"
1051 select GENERIC_ALLOCATOR
1052 default y
1053 ---help---
1054 Machine Check support allows the processor to notify the
1055 kernel if it detects a problem (e.g. overheating, data corruption).
1056 The action the kernel takes depends on the severity of the problem,
1057 ranging from warning messages to halting the machine.
1058
1059 config X86_MCELOG_LEGACY
1060 bool "Support for deprecated /dev/mcelog character device"
1061 depends on X86_MCE
1062 ---help---
1063 Enable support for /dev/mcelog which is needed by the old mcelog
1064 userspace logging daemon. Consider switching to the new generation
1065 rasdaemon solution.
1066
1067 config X86_MCE_INTEL
1068 def_bool y
1069 prompt "Intel MCE features"
1070 depends on X86_MCE && X86_LOCAL_APIC
1071 ---help---
1072 Additional support for intel specific MCE features such as
1073 the thermal monitor.
1074
1075 config X86_MCE_AMD
1076 def_bool y
1077 prompt "AMD MCE features"
1078 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1079 ---help---
1080 Additional support for AMD specific MCE features such as
1081 the DRAM Error Threshold.
1082
1083 config X86_ANCIENT_MCE
1084 bool "Support for old Pentium 5 / WinChip machine checks"
1085 depends on X86_32 && X86_MCE
1086 ---help---
1087 Include support for machine check handling on old Pentium 5 or WinChip
1088 systems. These typically need to be enabled explicitly on the command
1089 line.
1090
1091 config X86_MCE_THRESHOLD
1092 depends on X86_MCE_AMD || X86_MCE_INTEL
1093 def_bool y
1094
1095 config X86_MCE_INJECT
1096 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1097 tristate "Machine check injector support"
1098 ---help---
1099 Provide support for injecting machine checks for testing purposes.
1100 If you don't know what a machine check is and you don't do kernel
1101 QA it is safe to say n.
1102
1103 config X86_THERMAL_VECTOR
1104 def_bool y
1105 depends on X86_MCE_INTEL
1106
1107 source "arch/x86/events/Kconfig"
1108
1109 config X86_LEGACY_VM86
1110 bool "Legacy VM86 support"
1111 default n
1112 depends on X86_32
1113 ---help---
1114 This option allows user programs to put the CPU into V8086
1115 mode, which is an 80286-era approximation of 16-bit real mode.
1116
1117 Some very old versions of X and/or vbetool require this option
1118 for user mode setting. Similarly, DOSEMU will use it if
1119 available to accelerate real mode DOS programs. However, any
1120 recent version of DOSEMU, X, or vbetool should be fully
1121 functional even without kernel VM86 support, as they will all
1122 fall back to software emulation. Nevertheless, if you are using
1123 a 16-bit DOS program where 16-bit performance matters, vm86
1124 mode might be faster than emulation and you might want to
1125 enable this option.
1126
1127 Note that any app that works on a 64-bit kernel is unlikely to
1128 need this option, as 64-bit kernels don't, and can't, support
1129 V8086 mode. This option is also unrelated to 16-bit protected
1130 mode and is not needed to run most 16-bit programs under Wine.
1131
1132 Enabling this option increases the complexity of the kernel
1133 and slows down exception handling a tiny bit.
1134
1135 If unsure, say N here.
1136
1137 config VM86
1138 bool
1139 default X86_LEGACY_VM86
1140
1141 config X86_16BIT
1142 bool "Enable support for 16-bit segments" if EXPERT
1143 default y
1144 depends on MODIFY_LDT_SYSCALL
1145 ---help---
1146 This option is required by programs like Wine to run 16-bit
1147 protected mode legacy code on x86 processors. Disabling
1148 this option saves about 300 bytes on i386, or around 6K text
1149 plus 16K runtime memory on x86-64,
1150
1151 config X86_ESPFIX32
1152 def_bool y
1153 depends on X86_16BIT && X86_32
1154
1155 config X86_ESPFIX64
1156 def_bool y
1157 depends on X86_16BIT && X86_64
1158
1159 config X86_VSYSCALL_EMULATION
1160 bool "Enable vsyscall emulation" if EXPERT
1161 default y
1162 depends on X86_64
1163 ---help---
1164 This enables emulation of the legacy vsyscall page. Disabling
1165 it is roughly equivalent to booting with vsyscall=none, except
1166 that it will also disable the helpful warning if a program
1167 tries to use a vsyscall. With this option set to N, offending
1168 programs will just segfault, citing addresses of the form
1169 0xffffffffff600?00.
1170
1171 This option is required by many programs built before 2013, and
1172 care should be used even with newer programs if set to N.
1173
1174 Disabling this option saves about 7K of kernel size and
1175 possibly 4K of additional runtime pagetable memory.
1176
1177 config TOSHIBA
1178 tristate "Toshiba Laptop support"
1179 depends on X86_32
1180 ---help---
1181 This adds a driver to safely access the System Management Mode of
1182 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1183 not work on models with a Phoenix BIOS. The System Management Mode
1184 is used to set the BIOS and power saving options on Toshiba portables.
1185
1186 For information on utilities to make use of this driver see the
1187 Toshiba Linux utilities web site at:
1188 <http://www.buzzard.org.uk/toshiba/>.
1189
1190 Say Y if you intend to run this kernel on a Toshiba portable.
1191 Say N otherwise.
1192
1193 config I8K
1194 tristate "Dell i8k legacy laptop support"
1195 select HWMON
1196 select SENSORS_DELL_SMM
1197 ---help---
1198 This option enables legacy /proc/i8k userspace interface in hwmon
1199 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1200 temperature and allows controlling fan speeds of Dell laptops via
1201 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1202 it reports also power and hotkey status. For fan speed control is
1203 needed userspace package i8kutils.
1204
1205 Say Y if you intend to run this kernel on old Dell laptops or want to
1206 use userspace package i8kutils.
1207 Say N otherwise.
1208
1209 config X86_REBOOTFIXUPS
1210 bool "Enable X86 board specific fixups for reboot"
1211 depends on X86_32
1212 ---help---
1213 This enables chipset and/or board specific fixups to be done
1214 in order to get reboot to work correctly. This is only needed on
1215 some combinations of hardware and BIOS. The symptom, for which
1216 this config is intended, is when reboot ends with a stalled/hung
1217 system.
1218
1219 Currently, the only fixup is for the Geode machines using
1220 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1221
1222 Say Y if you want to enable the fixup. Currently, it's safe to
1223 enable this option even if you don't need it.
1224 Say N otherwise.
1225
1226 config MICROCODE
1227 bool "CPU microcode loading support"
1228 default y
1229 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1230 select FW_LOADER
1231 ---help---
1232 If you say Y here, you will be able to update the microcode on
1233 Intel and AMD processors. The Intel support is for the IA32 family,
1234 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1235 AMD support is for families 0x10 and later. You will obviously need
1236 the actual microcode binary data itself which is not shipped with
1237 the Linux kernel.
1238
1239 The preferred method to load microcode from a detached initrd is described
1240 in Documentation/x86/early-microcode.txt. For that you need to enable
1241 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1242 initrd for microcode blobs.
1243
1244 In addition, you can build-in the microcode into the kernel. For that you
1245 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1246 to the CONFIG_EXTRA_FIRMWARE config option.
1247
1248 config MICROCODE_INTEL
1249 bool "Intel microcode loading support"
1250 depends on MICROCODE
1251 default MICROCODE
1252 select FW_LOADER
1253 ---help---
1254 This options enables microcode patch loading support for Intel
1255 processors.
1256
1257 For the current Intel microcode data package go to
1258 <https://downloadcenter.intel.com> and search for
1259 'Linux Processor Microcode Data File'.
1260
1261 config MICROCODE_AMD
1262 bool "AMD microcode loading support"
1263 depends on MICROCODE
1264 select FW_LOADER
1265 ---help---
1266 If you select this option, microcode patch loading support for AMD
1267 processors will be enabled.
1268
1269 config MICROCODE_OLD_INTERFACE
1270 def_bool y
1271 depends on MICROCODE
1272
1273 config X86_MSR
1274 tristate "/dev/cpu/*/msr - Model-specific register support"
1275 ---help---
1276 This device gives privileged processes access to the x86
1277 Model-Specific Registers (MSRs). It is a character device with
1278 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1279 MSR accesses are directed to a specific CPU on multi-processor
1280 systems.
1281
1282 config X86_CPUID
1283 tristate "/dev/cpu/*/cpuid - CPU information support"
1284 ---help---
1285 This device gives processes access to the x86 CPUID instruction to
1286 be executed on a specific processor. It is a character device
1287 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1288 /dev/cpu/31/cpuid.
1289
1290 choice
1291 prompt "High Memory Support"
1292 default HIGHMEM4G
1293 depends on X86_32
1294
1295 config NOHIGHMEM
1296 bool "off"
1297 ---help---
1298 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1299 However, the address space of 32-bit x86 processors is only 4
1300 Gigabytes large. That means that, if you have a large amount of
1301 physical memory, not all of it can be "permanently mapped" by the
1302 kernel. The physical memory that's not permanently mapped is called
1303 "high memory".
1304
1305 If you are compiling a kernel which will never run on a machine with
1306 more than 1 Gigabyte total physical RAM, answer "off" here (default
1307 choice and suitable for most users). This will result in a "3GB/1GB"
1308 split: 3GB are mapped so that each process sees a 3GB virtual memory
1309 space and the remaining part of the 4GB virtual memory space is used
1310 by the kernel to permanently map as much physical memory as
1311 possible.
1312
1313 If the machine has between 1 and 4 Gigabytes physical RAM, then
1314 answer "4GB" here.
1315
1316 If more than 4 Gigabytes is used then answer "64GB" here. This
1317 selection turns Intel PAE (Physical Address Extension) mode on.
1318 PAE implements 3-level paging on IA32 processors. PAE is fully
1319 supported by Linux, PAE mode is implemented on all recent Intel
1320 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1321 then the kernel will not boot on CPUs that don't support PAE!
1322
1323 The actual amount of total physical memory will either be
1324 auto detected or can be forced by using a kernel command line option
1325 such as "mem=256M". (Try "man bootparam" or see the documentation of
1326 your boot loader (lilo or loadlin) about how to pass options to the
1327 kernel at boot time.)
1328
1329 If unsure, say "off".
1330
1331 config HIGHMEM4G
1332 bool "4GB"
1333 ---help---
1334 Select this if you have a 32-bit processor and between 1 and 4
1335 gigabytes of physical RAM.
1336
1337 config HIGHMEM64G
1338 bool "64GB"
1339 depends on !M486
1340 select X86_PAE
1341 ---help---
1342 Select this if you have a 32-bit processor and more than 4
1343 gigabytes of physical RAM.
1344
1345 endchoice
1346
1347 choice
1348 prompt "Memory split" if EXPERT
1349 default VMSPLIT_3G
1350 depends on X86_32
1351 ---help---
1352 Select the desired split between kernel and user memory.
1353
1354 If the address range available to the kernel is less than the
1355 physical memory installed, the remaining memory will be available
1356 as "high memory". Accessing high memory is a little more costly
1357 than low memory, as it needs to be mapped into the kernel first.
1358 Note that increasing the kernel address space limits the range
1359 available to user programs, making the address space there
1360 tighter. Selecting anything other than the default 3G/1G split
1361 will also likely make your kernel incompatible with binary-only
1362 kernel modules.
1363
1364 If you are not absolutely sure what you are doing, leave this
1365 option alone!
1366
1367 config VMSPLIT_3G
1368 bool "3G/1G user/kernel split"
1369 config VMSPLIT_3G_OPT
1370 depends on !X86_PAE
1371 bool "3G/1G user/kernel split (for full 1G low memory)"
1372 config VMSPLIT_2G
1373 bool "2G/2G user/kernel split"
1374 config VMSPLIT_2G_OPT
1375 depends on !X86_PAE
1376 bool "2G/2G user/kernel split (for full 2G low memory)"
1377 config VMSPLIT_1G
1378 bool "1G/3G user/kernel split"
1379 endchoice
1380
1381 config PAGE_OFFSET
1382 hex
1383 default 0xB0000000 if VMSPLIT_3G_OPT
1384 default 0x80000000 if VMSPLIT_2G
1385 default 0x78000000 if VMSPLIT_2G_OPT
1386 default 0x40000000 if VMSPLIT_1G
1387 default 0xC0000000
1388 depends on X86_32
1389
1390 config HIGHMEM
1391 def_bool y
1392 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1393
1394 config X86_PAE
1395 bool "PAE (Physical Address Extension) Support"
1396 depends on X86_32 && !HIGHMEM4G
1397 select SWIOTLB
1398 ---help---
1399 PAE is required for NX support, and furthermore enables
1400 larger swapspace support for non-overcommit purposes. It
1401 has the cost of more pagetable lookup overhead, and also
1402 consumes more pagetable space per process.
1403
1404 config X86_5LEVEL
1405 bool "Enable 5-level page tables support"
1406 depends on X86_64
1407 ---help---
1408 5-level paging enables access to larger address space:
1409 upto 128 PiB of virtual address space and 4 PiB of
1410 physical address space.
1411
1412 It will be supported by future Intel CPUs.
1413
1414 Note: a kernel with this option enabled can only be booted
1415 on machines that support the feature.
1416
1417 See Documentation/x86/x86_64/5level-paging.txt for more
1418 information.
1419
1420 Say N if unsure.
1421
1422 config ARCH_PHYS_ADDR_T_64BIT
1423 def_bool y
1424 depends on X86_64 || X86_PAE
1425
1426 config ARCH_DMA_ADDR_T_64BIT
1427 def_bool y
1428 depends on X86_64 || HIGHMEM64G
1429
1430 config X86_DIRECT_GBPAGES
1431 def_bool y
1432 depends on X86_64 && !DEBUG_PAGEALLOC
1433 ---help---
1434 Certain kernel features effectively disable kernel
1435 linear 1 GB mappings (even if the CPU otherwise
1436 supports them), so don't confuse the user by printing
1437 that we have them enabled.
1438
1439 config ARCH_HAS_MEM_ENCRYPT
1440 def_bool y
1441
1442 config AMD_MEM_ENCRYPT
1443 bool "AMD Secure Memory Encryption (SME) support"
1444 depends on X86_64 && CPU_SUP_AMD
1445 ---help---
1446 Say yes to enable support for the encryption of system memory.
1447 This requires an AMD processor that supports Secure Memory
1448 Encryption (SME).
1449
1450 config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1451 bool "Activate AMD Secure Memory Encryption (SME) by default"
1452 default y
1453 depends on AMD_MEM_ENCRYPT
1454 ---help---
1455 Say yes to have system memory encrypted by default if running on
1456 an AMD processor that supports Secure Memory Encryption (SME).
1457
1458 If set to Y, then the encryption of system memory can be
1459 deactivated with the mem_encrypt=off command line option.
1460
1461 If set to N, then the encryption of system memory can be
1462 activated with the mem_encrypt=on command line option.
1463
1464 config ARCH_USE_MEMREMAP_PROT
1465 def_bool y
1466 depends on AMD_MEM_ENCRYPT
1467
1468 # Common NUMA Features
1469 config NUMA
1470 bool "Numa Memory Allocation and Scheduler Support"
1471 depends on SMP
1472 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1473 default y if X86_BIGSMP
1474 ---help---
1475 Enable NUMA (Non Uniform Memory Access) support.
1476
1477 The kernel will try to allocate memory used by a CPU on the
1478 local memory controller of the CPU and add some more
1479 NUMA awareness to the kernel.
1480
1481 For 64-bit this is recommended if the system is Intel Core i7
1482 (or later), AMD Opteron, or EM64T NUMA.
1483
1484 For 32-bit this is only needed if you boot a 32-bit
1485 kernel on a 64-bit NUMA platform.
1486
1487 Otherwise, you should say N.
1488
1489 config AMD_NUMA
1490 def_bool y
1491 prompt "Old style AMD Opteron NUMA detection"
1492 depends on X86_64 && NUMA && PCI
1493 ---help---
1494 Enable AMD NUMA node topology detection. You should say Y here if
1495 you have a multi processor AMD system. This uses an old method to
1496 read the NUMA configuration directly from the builtin Northbridge
1497 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1498 which also takes priority if both are compiled in.
1499
1500 config X86_64_ACPI_NUMA
1501 def_bool y
1502 prompt "ACPI NUMA detection"
1503 depends on X86_64 && NUMA && ACPI && PCI
1504 select ACPI_NUMA
1505 ---help---
1506 Enable ACPI SRAT based node topology detection.
1507
1508 # Some NUMA nodes have memory ranges that span
1509 # other nodes. Even though a pfn is valid and
1510 # between a node's start and end pfns, it may not
1511 # reside on that node. See memmap_init_zone()
1512 # for details.
1513 config NODES_SPAN_OTHER_NODES
1514 def_bool y
1515 depends on X86_64_ACPI_NUMA
1516
1517 config NUMA_EMU
1518 bool "NUMA emulation"
1519 depends on NUMA
1520 ---help---
1521 Enable NUMA emulation. A flat machine will be split
1522 into virtual nodes when booted with "numa=fake=N", where N is the
1523 number of nodes. This is only useful for debugging.
1524
1525 config NODES_SHIFT
1526 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1527 range 1 10
1528 default "10" if MAXSMP
1529 default "6" if X86_64
1530 default "3"
1531 depends on NEED_MULTIPLE_NODES
1532 ---help---
1533 Specify the maximum number of NUMA Nodes available on the target
1534 system. Increases memory reserved to accommodate various tables.
1535
1536 config ARCH_HAVE_MEMORY_PRESENT
1537 def_bool y
1538 depends on X86_32 && DISCONTIGMEM
1539
1540 config NEED_NODE_MEMMAP_SIZE
1541 def_bool y
1542 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1543
1544 config ARCH_FLATMEM_ENABLE
1545 def_bool y
1546 depends on X86_32 && !NUMA
1547
1548 config ARCH_DISCONTIGMEM_ENABLE
1549 def_bool y
1550 depends on NUMA && X86_32
1551
1552 config ARCH_DISCONTIGMEM_DEFAULT
1553 def_bool y
1554 depends on NUMA && X86_32
1555
1556 config ARCH_SPARSEMEM_ENABLE
1557 def_bool y
1558 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1559 select SPARSEMEM_STATIC if X86_32
1560 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1561
1562 config ARCH_SPARSEMEM_DEFAULT
1563 def_bool y
1564 depends on X86_64
1565
1566 config ARCH_SELECT_MEMORY_MODEL
1567 def_bool y
1568 depends on ARCH_SPARSEMEM_ENABLE
1569
1570 config ARCH_MEMORY_PROBE
1571 bool "Enable sysfs memory/probe interface"
1572 depends on X86_64 && MEMORY_HOTPLUG
1573 help
1574 This option enables a sysfs memory/probe interface for testing.
1575 See Documentation/memory-hotplug.txt for more information.
1576 If you are unsure how to answer this question, answer N.
1577
1578 config ARCH_PROC_KCORE_TEXT
1579 def_bool y
1580 depends on X86_64 && PROC_KCORE
1581
1582 config ILLEGAL_POINTER_VALUE
1583 hex
1584 default 0 if X86_32
1585 default 0xdead000000000000 if X86_64
1586
1587 source "mm/Kconfig"
1588
1589 config X86_PMEM_LEGACY_DEVICE
1590 bool
1591
1592 config X86_PMEM_LEGACY
1593 tristate "Support non-standard NVDIMMs and ADR protected memory"
1594 depends on PHYS_ADDR_T_64BIT
1595 depends on BLK_DEV
1596 select X86_PMEM_LEGACY_DEVICE
1597 select LIBNVDIMM
1598 help
1599 Treat memory marked using the non-standard e820 type of 12 as used
1600 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1601 The kernel will offer these regions to the 'pmem' driver so
1602 they can be used for persistent storage.
1603
1604 Say Y if unsure.
1605
1606 config HIGHPTE
1607 bool "Allocate 3rd-level pagetables from highmem"
1608 depends on HIGHMEM
1609 ---help---
1610 The VM uses one page table entry for each page of physical memory.
1611 For systems with a lot of RAM, this can be wasteful of precious
1612 low memory. Setting this option will put user-space page table
1613 entries in high memory.
1614
1615 config X86_CHECK_BIOS_CORRUPTION
1616 bool "Check for low memory corruption"
1617 ---help---
1618 Periodically check for memory corruption in low memory, which
1619 is suspected to be caused by BIOS. Even when enabled in the
1620 configuration, it is disabled at runtime. Enable it by
1621 setting "memory_corruption_check=1" on the kernel command
1622 line. By default it scans the low 64k of memory every 60
1623 seconds; see the memory_corruption_check_size and
1624 memory_corruption_check_period parameters in
1625 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1626
1627 When enabled with the default parameters, this option has
1628 almost no overhead, as it reserves a relatively small amount
1629 of memory and scans it infrequently. It both detects corruption
1630 and prevents it from affecting the running system.
1631
1632 It is, however, intended as a diagnostic tool; if repeatable
1633 BIOS-originated corruption always affects the same memory,
1634 you can use memmap= to prevent the kernel from using that
1635 memory.
1636
1637 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1638 bool "Set the default setting of memory_corruption_check"
1639 depends on X86_CHECK_BIOS_CORRUPTION
1640 default y
1641 ---help---
1642 Set whether the default state of memory_corruption_check is
1643 on or off.
1644
1645 config X86_RESERVE_LOW
1646 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1647 default 64
1648 range 4 640
1649 ---help---
1650 Specify the amount of low memory to reserve for the BIOS.
1651
1652 The first page contains BIOS data structures that the kernel
1653 must not use, so that page must always be reserved.
1654
1655 By default we reserve the first 64K of physical RAM, as a
1656 number of BIOSes are known to corrupt that memory range
1657 during events such as suspend/resume or monitor cable
1658 insertion, so it must not be used by the kernel.
1659
1660 You can set this to 4 if you are absolutely sure that you
1661 trust the BIOS to get all its memory reservations and usages
1662 right. If you know your BIOS have problems beyond the
1663 default 64K area, you can set this to 640 to avoid using the
1664 entire low memory range.
1665
1666 If you have doubts about the BIOS (e.g. suspend/resume does
1667 not work or there's kernel crashes after certain hardware
1668 hotplug events) then you might want to enable
1669 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1670 typical corruption patterns.
1671
1672 Leave this to the default value of 64 if you are unsure.
1673
1674 config MATH_EMULATION
1675 bool
1676 depends on MODIFY_LDT_SYSCALL
1677 prompt "Math emulation" if X86_32
1678 ---help---
1679 Linux can emulate a math coprocessor (used for floating point
1680 operations) if you don't have one. 486DX and Pentium processors have
1681 a math coprocessor built in, 486SX and 386 do not, unless you added
1682 a 487DX or 387, respectively. (The messages during boot time can
1683 give you some hints here ["man dmesg"].) Everyone needs either a
1684 coprocessor or this emulation.
1685
1686 If you don't have a math coprocessor, you need to say Y here; if you
1687 say Y here even though you have a coprocessor, the coprocessor will
1688 be used nevertheless. (This behavior can be changed with the kernel
1689 command line option "no387", which comes handy if your coprocessor
1690 is broken. Try "man bootparam" or see the documentation of your boot
1691 loader (lilo or loadlin) about how to pass options to the kernel at
1692 boot time.) This means that it is a good idea to say Y here if you
1693 intend to use this kernel on different machines.
1694
1695 More information about the internals of the Linux math coprocessor
1696 emulation can be found in <file:arch/x86/math-emu/README>.
1697
1698 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1699 kernel, it won't hurt.
1700
1701 config MTRR
1702 def_bool y
1703 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1704 ---help---
1705 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1706 the Memory Type Range Registers (MTRRs) may be used to control
1707 processor access to memory ranges. This is most useful if you have
1708 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1709 allows bus write transfers to be combined into a larger transfer
1710 before bursting over the PCI/AGP bus. This can increase performance
1711 of image write operations 2.5 times or more. Saying Y here creates a
1712 /proc/mtrr file which may be used to manipulate your processor's
1713 MTRRs. Typically the X server should use this.
1714
1715 This code has a reasonably generic interface so that similar
1716 control registers on other processors can be easily supported
1717 as well:
1718
1719 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1720 Registers (ARRs) which provide a similar functionality to MTRRs. For
1721 these, the ARRs are used to emulate the MTRRs.
1722 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1723 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1724 write-combining. All of these processors are supported by this code
1725 and it makes sense to say Y here if you have one of them.
1726
1727 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1728 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1729 can lead to all sorts of problems, so it's good to say Y here.
1730
1731 You can safely say Y even if your machine doesn't have MTRRs, you'll
1732 just add about 9 KB to your kernel.
1733
1734 See <file:Documentation/x86/mtrr.txt> for more information.
1735
1736 config MTRR_SANITIZER
1737 def_bool y
1738 prompt "MTRR cleanup support"
1739 depends on MTRR
1740 ---help---
1741 Convert MTRR layout from continuous to discrete, so X drivers can
1742 add writeback entries.
1743
1744 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1745 The largest mtrr entry size for a continuous block can be set with
1746 mtrr_chunk_size.
1747
1748 If unsure, say Y.
1749
1750 config MTRR_SANITIZER_ENABLE_DEFAULT
1751 int "MTRR cleanup enable value (0-1)"
1752 range 0 1
1753 default "0"
1754 depends on MTRR_SANITIZER
1755 ---help---
1756 Enable mtrr cleanup default value
1757
1758 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1759 int "MTRR cleanup spare reg num (0-7)"
1760 range 0 7
1761 default "1"
1762 depends on MTRR_SANITIZER
1763 ---help---
1764 mtrr cleanup spare entries default, it can be changed via
1765 mtrr_spare_reg_nr=N on the kernel command line.
1766
1767 config X86_PAT
1768 def_bool y
1769 prompt "x86 PAT support" if EXPERT
1770 depends on MTRR
1771 ---help---
1772 Use PAT attributes to setup page level cache control.
1773
1774 PATs are the modern equivalents of MTRRs and are much more
1775 flexible than MTRRs.
1776
1777 Say N here if you see bootup problems (boot crash, boot hang,
1778 spontaneous reboots) or a non-working video driver.
1779
1780 If unsure, say Y.
1781
1782 config ARCH_USES_PG_UNCACHED
1783 def_bool y
1784 depends on X86_PAT
1785
1786 config ARCH_RANDOM
1787 def_bool y
1788 prompt "x86 architectural random number generator" if EXPERT
1789 ---help---
1790 Enable the x86 architectural RDRAND instruction
1791 (Intel Bull Mountain technology) to generate random numbers.
1792 If supported, this is a high bandwidth, cryptographically
1793 secure hardware random number generator.
1794
1795 config X86_SMAP
1796 def_bool y
1797 prompt "Supervisor Mode Access Prevention" if EXPERT
1798 ---help---
1799 Supervisor Mode Access Prevention (SMAP) is a security
1800 feature in newer Intel processors. There is a small
1801 performance cost if this enabled and turned on; there is
1802 also a small increase in the kernel size if this is enabled.
1803
1804 If unsure, say Y.
1805
1806 config X86_INTEL_UMIP
1807 def_bool n
1808 depends on CPU_SUP_INTEL
1809 prompt "Intel User Mode Instruction Prevention" if EXPERT
1810 ---help---
1811 The User Mode Instruction Prevention (UMIP) is a security
1812 feature in newer Intel processors. If enabled, a general
1813 protection fault is issued if the instructions SGDT, SLDT,
1814 SIDT, SMSW and STR are executed in user mode.
1815
1816 config X86_INTEL_MPX
1817 prompt "Intel MPX (Memory Protection Extensions)"
1818 def_bool n
1819 # Note: only available in 64-bit mode due to VMA flags shortage
1820 depends on CPU_SUP_INTEL && X86_64
1821 select ARCH_USES_HIGH_VMA_FLAGS
1822 ---help---
1823 MPX provides hardware features that can be used in
1824 conjunction with compiler-instrumented code to check
1825 memory references. It is designed to detect buffer
1826 overflow or underflow bugs.
1827
1828 This option enables running applications which are
1829 instrumented or otherwise use MPX. It does not use MPX
1830 itself inside the kernel or to protect the kernel
1831 against bad memory references.
1832
1833 Enabling this option will make the kernel larger:
1834 ~8k of kernel text and 36 bytes of data on a 64-bit
1835 defconfig. It adds a long to the 'mm_struct' which
1836 will increase the kernel memory overhead of each
1837 process and adds some branches to paths used during
1838 exec() and munmap().
1839
1840 For details, see Documentation/x86/intel_mpx.txt
1841
1842 If unsure, say N.
1843
1844 config X86_INTEL_MEMORY_PROTECTION_KEYS
1845 prompt "Intel Memory Protection Keys"
1846 def_bool y
1847 # Note: only available in 64-bit mode
1848 depends on CPU_SUP_INTEL && X86_64
1849 select ARCH_USES_HIGH_VMA_FLAGS
1850 select ARCH_HAS_PKEYS
1851 ---help---
1852 Memory Protection Keys provides a mechanism for enforcing
1853 page-based protections, but without requiring modification of the
1854 page tables when an application changes protection domains.
1855
1856 For details, see Documentation/x86/protection-keys.txt
1857
1858 If unsure, say y.
1859
1860 config EFI
1861 bool "EFI runtime service support"
1862 depends on ACPI
1863 select UCS2_STRING
1864 select EFI_RUNTIME_WRAPPERS
1865 ---help---
1866 This enables the kernel to use EFI runtime services that are
1867 available (such as the EFI variable services).
1868
1869 This option is only useful on systems that have EFI firmware.
1870 In addition, you should use the latest ELILO loader available
1871 at <http://elilo.sourceforge.net> in order to take advantage
1872 of EFI runtime services. However, even with this option, the
1873 resultant kernel should continue to boot on existing non-EFI
1874 platforms.
1875
1876 config EFI_STUB
1877 bool "EFI stub support"
1878 depends on EFI && !X86_USE_3DNOW
1879 select RELOCATABLE
1880 ---help---
1881 This kernel feature allows a bzImage to be loaded directly
1882 by EFI firmware without the use of a bootloader.
1883
1884 See Documentation/efi-stub.txt for more information.
1885
1886 config EFI_MIXED
1887 bool "EFI mixed-mode support"
1888 depends on EFI_STUB && X86_64
1889 ---help---
1890 Enabling this feature allows a 64-bit kernel to be booted
1891 on a 32-bit firmware, provided that your CPU supports 64-bit
1892 mode.
1893
1894 Note that it is not possible to boot a mixed-mode enabled
1895 kernel via the EFI boot stub - a bootloader that supports
1896 the EFI handover protocol must be used.
1897
1898 If unsure, say N.
1899
1900 config SECCOMP
1901 def_bool y
1902 prompt "Enable seccomp to safely compute untrusted bytecode"
1903 ---help---
1904 This kernel feature is useful for number crunching applications
1905 that may need to compute untrusted bytecode during their
1906 execution. By using pipes or other transports made available to
1907 the process as file descriptors supporting the read/write
1908 syscalls, it's possible to isolate those applications in
1909 their own address space using seccomp. Once seccomp is
1910 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1911 and the task is only allowed to execute a few safe syscalls
1912 defined by each seccomp mode.
1913
1914 If unsure, say Y. Only embedded should say N here.
1915
1916 source kernel/Kconfig.hz
1917
1918 config KEXEC
1919 bool "kexec system call"
1920 select KEXEC_CORE
1921 ---help---
1922 kexec is a system call that implements the ability to shutdown your
1923 current kernel, and to start another kernel. It is like a reboot
1924 but it is independent of the system firmware. And like a reboot
1925 you can start any kernel with it, not just Linux.
1926
1927 The name comes from the similarity to the exec system call.
1928
1929 It is an ongoing process to be certain the hardware in a machine
1930 is properly shutdown, so do not be surprised if this code does not
1931 initially work for you. As of this writing the exact hardware
1932 interface is strongly in flux, so no good recommendation can be
1933 made.
1934
1935 config KEXEC_FILE
1936 bool "kexec file based system call"
1937 select KEXEC_CORE
1938 select BUILD_BIN2C
1939 depends on X86_64
1940 depends on CRYPTO=y
1941 depends on CRYPTO_SHA256=y
1942 ---help---
1943 This is new version of kexec system call. This system call is
1944 file based and takes file descriptors as system call argument
1945 for kernel and initramfs as opposed to list of segments as
1946 accepted by previous system call.
1947
1948 config KEXEC_VERIFY_SIG
1949 bool "Verify kernel signature during kexec_file_load() syscall"
1950 depends on KEXEC_FILE
1951 ---help---
1952 This option makes kernel signature verification mandatory for
1953 the kexec_file_load() syscall.
1954
1955 In addition to that option, you need to enable signature
1956 verification for the corresponding kernel image type being
1957 loaded in order for this to work.
1958
1959 config KEXEC_BZIMAGE_VERIFY_SIG
1960 bool "Enable bzImage signature verification support"
1961 depends on KEXEC_VERIFY_SIG
1962 depends on SIGNED_PE_FILE_VERIFICATION
1963 select SYSTEM_TRUSTED_KEYRING
1964 ---help---
1965 Enable bzImage signature verification support.
1966
1967 config CRASH_DUMP
1968 bool "kernel crash dumps"
1969 depends on X86_64 || (X86_32 && HIGHMEM)
1970 ---help---
1971 Generate crash dump after being started by kexec.
1972 This should be normally only set in special crash dump kernels
1973 which are loaded in the main kernel with kexec-tools into
1974 a specially reserved region and then later executed after
1975 a crash by kdump/kexec. The crash dump kernel must be compiled
1976 to a memory address not used by the main kernel or BIOS using
1977 PHYSICAL_START, or it must be built as a relocatable image
1978 (CONFIG_RELOCATABLE=y).
1979 For more details see Documentation/kdump/kdump.txt
1980
1981 config KEXEC_JUMP
1982 bool "kexec jump"
1983 depends on KEXEC && HIBERNATION
1984 ---help---
1985 Jump between original kernel and kexeced kernel and invoke
1986 code in physical address mode via KEXEC
1987
1988 config PHYSICAL_START
1989 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1990 default "0x1000000"
1991 ---help---
1992 This gives the physical address where the kernel is loaded.
1993
1994 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1995 bzImage will decompress itself to above physical address and
1996 run from there. Otherwise, bzImage will run from the address where
1997 it has been loaded by the boot loader and will ignore above physical
1998 address.
1999
2000 In normal kdump cases one does not have to set/change this option
2001 as now bzImage can be compiled as a completely relocatable image
2002 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2003 address. This option is mainly useful for the folks who don't want
2004 to use a bzImage for capturing the crash dump and want to use a
2005 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2006 to be specifically compiled to run from a specific memory area
2007 (normally a reserved region) and this option comes handy.
2008
2009 So if you are using bzImage for capturing the crash dump,
2010 leave the value here unchanged to 0x1000000 and set
2011 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2012 for capturing the crash dump change this value to start of
2013 the reserved region. In other words, it can be set based on
2014 the "X" value as specified in the "crashkernel=YM@XM"
2015 command line boot parameter passed to the panic-ed
2016 kernel. Please take a look at Documentation/kdump/kdump.txt
2017 for more details about crash dumps.
2018
2019 Usage of bzImage for capturing the crash dump is recommended as
2020 one does not have to build two kernels. Same kernel can be used
2021 as production kernel and capture kernel. Above option should have
2022 gone away after relocatable bzImage support is introduced. But it
2023 is present because there are users out there who continue to use
2024 vmlinux for dump capture. This option should go away down the
2025 line.
2026
2027 Don't change this unless you know what you are doing.
2028
2029 config RELOCATABLE
2030 bool "Build a relocatable kernel"
2031 default y
2032 ---help---
2033 This builds a kernel image that retains relocation information
2034 so it can be loaded someplace besides the default 1MB.
2035 The relocations tend to make the kernel binary about 10% larger,
2036 but are discarded at runtime.
2037
2038 One use is for the kexec on panic case where the recovery kernel
2039 must live at a different physical address than the primary
2040 kernel.
2041
2042 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2043 it has been loaded at and the compile time physical address
2044 (CONFIG_PHYSICAL_START) is used as the minimum location.
2045
2046 config RANDOMIZE_BASE
2047 bool "Randomize the address of the kernel image (KASLR)"
2048 depends on RELOCATABLE
2049 default y
2050 ---help---
2051 In support of Kernel Address Space Layout Randomization (KASLR),
2052 this randomizes the physical address at which the kernel image
2053 is decompressed and the virtual address where the kernel
2054 image is mapped, as a security feature that deters exploit
2055 attempts relying on knowledge of the location of kernel
2056 code internals.
2057
2058 On 64-bit, the kernel physical and virtual addresses are
2059 randomized separately. The physical address will be anywhere
2060 between 16MB and the top of physical memory (up to 64TB). The
2061 virtual address will be randomized from 16MB up to 1GB (9 bits
2062 of entropy). Note that this also reduces the memory space
2063 available to kernel modules from 1.5GB to 1GB.
2064
2065 On 32-bit, the kernel physical and virtual addresses are
2066 randomized together. They will be randomized from 16MB up to
2067 512MB (8 bits of entropy).
2068
2069 Entropy is generated using the RDRAND instruction if it is
2070 supported. If RDTSC is supported, its value is mixed into
2071 the entropy pool as well. If neither RDRAND nor RDTSC are
2072 supported, then entropy is read from the i8254 timer. The
2073 usable entropy is limited by the kernel being built using
2074 2GB addressing, and that PHYSICAL_ALIGN must be at a
2075 minimum of 2MB. As a result, only 10 bits of entropy are
2076 theoretically possible, but the implementations are further
2077 limited due to memory layouts.
2078
2079 If unsure, say Y.
2080
2081 # Relocation on x86 needs some additional build support
2082 config X86_NEED_RELOCS
2083 def_bool y
2084 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2085
2086 config PHYSICAL_ALIGN
2087 hex "Alignment value to which kernel should be aligned"
2088 default "0x200000"
2089 range 0x2000 0x1000000 if X86_32
2090 range 0x200000 0x1000000 if X86_64
2091 ---help---
2092 This value puts the alignment restrictions on physical address
2093 where kernel is loaded and run from. Kernel is compiled for an
2094 address which meets above alignment restriction.
2095
2096 If bootloader loads the kernel at a non-aligned address and
2097 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2098 address aligned to above value and run from there.
2099
2100 If bootloader loads the kernel at a non-aligned address and
2101 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2102 load address and decompress itself to the address it has been
2103 compiled for and run from there. The address for which kernel is
2104 compiled already meets above alignment restrictions. Hence the
2105 end result is that kernel runs from a physical address meeting
2106 above alignment restrictions.
2107
2108 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2109 this value must be a multiple of 0x200000.
2110
2111 Don't change this unless you know what you are doing.
2112
2113 config RANDOMIZE_MEMORY
2114 bool "Randomize the kernel memory sections"
2115 depends on X86_64
2116 depends on RANDOMIZE_BASE
2117 default RANDOMIZE_BASE
2118 ---help---
2119 Randomizes the base virtual address of kernel memory sections
2120 (physical memory mapping, vmalloc & vmemmap). This security feature
2121 makes exploits relying on predictable memory locations less reliable.
2122
2123 The order of allocations remains unchanged. Entropy is generated in
2124 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2125 configuration have in average 30,000 different possible virtual
2126 addresses for each memory section.
2127
2128 If unsure, say Y.
2129
2130 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2131 hex "Physical memory mapping padding" if EXPERT
2132 depends on RANDOMIZE_MEMORY
2133 default "0xa" if MEMORY_HOTPLUG
2134 default "0x0"
2135 range 0x1 0x40 if MEMORY_HOTPLUG
2136 range 0x0 0x40
2137 ---help---
2138 Define the padding in terabytes added to the existing physical
2139 memory size during kernel memory randomization. It is useful
2140 for memory hotplug support but reduces the entropy available for
2141 address randomization.
2142
2143 If unsure, leave at the default value.
2144
2145 config HOTPLUG_CPU
2146 bool "Support for hot-pluggable CPUs"
2147 depends on SMP
2148 ---help---
2149 Say Y here to allow turning CPUs off and on. CPUs can be
2150 controlled through /sys/devices/system/cpu.
2151 ( Note: power management support will enable this option
2152 automatically on SMP systems. )
2153 Say N if you want to disable CPU hotplug.
2154
2155 config BOOTPARAM_HOTPLUG_CPU0
2156 bool "Set default setting of cpu0_hotpluggable"
2157 default n
2158 depends on HOTPLUG_CPU
2159 ---help---
2160 Set whether default state of cpu0_hotpluggable is on or off.
2161
2162 Say Y here to enable CPU0 hotplug by default. If this switch
2163 is turned on, there is no need to give cpu0_hotplug kernel
2164 parameter and the CPU0 hotplug feature is enabled by default.
2165
2166 Please note: there are two known CPU0 dependencies if you want
2167 to enable the CPU0 hotplug feature either by this switch or by
2168 cpu0_hotplug kernel parameter.
2169
2170 First, resume from hibernate or suspend always starts from CPU0.
2171 So hibernate and suspend are prevented if CPU0 is offline.
2172
2173 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2174 offline if any interrupt can not migrate out of CPU0. There may
2175 be other CPU0 dependencies.
2176
2177 Please make sure the dependencies are under your control before
2178 you enable this feature.
2179
2180 Say N if you don't want to enable CPU0 hotplug feature by default.
2181 You still can enable the CPU0 hotplug feature at boot by kernel
2182 parameter cpu0_hotplug.
2183
2184 config DEBUG_HOTPLUG_CPU0
2185 def_bool n
2186 prompt "Debug CPU0 hotplug"
2187 depends on HOTPLUG_CPU
2188 ---help---
2189 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2190 soon as possible and boots up userspace with CPU0 offlined. User
2191 can online CPU0 back after boot time.
2192
2193 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2194 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2195 compilation or giving cpu0_hotplug kernel parameter at boot.
2196
2197 If unsure, say N.
2198
2199 config COMPAT_VDSO
2200 def_bool n
2201 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2202 depends on COMPAT_32
2203 ---help---
2204 Certain buggy versions of glibc will crash if they are
2205 presented with a 32-bit vDSO that is not mapped at the address
2206 indicated in its segment table.
2207
2208 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2209 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2210 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2211 the only released version with the bug, but OpenSUSE 9
2212 contains a buggy "glibc 2.3.2".
2213
2214 The symptom of the bug is that everything crashes on startup, saying:
2215 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2216
2217 Saying Y here changes the default value of the vdso32 boot
2218 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2219 This works around the glibc bug but hurts performance.
2220
2221 If unsure, say N: if you are compiling your own kernel, you
2222 are unlikely to be using a buggy version of glibc.
2223
2224 choice
2225 prompt "vsyscall table for legacy applications"
2226 depends on X86_64
2227 default LEGACY_VSYSCALL_EMULATE
2228 help
2229 Legacy user code that does not know how to find the vDSO expects
2230 to be able to issue three syscalls by calling fixed addresses in
2231 kernel space. Since this location is not randomized with ASLR,
2232 it can be used to assist security vulnerability exploitation.
2233
2234 This setting can be changed at boot time via the kernel command
2235 line parameter vsyscall=[native|emulate|none].
2236
2237 On a system with recent enough glibc (2.14 or newer) and no
2238 static binaries, you can say None without a performance penalty
2239 to improve security.
2240
2241 If unsure, select "Emulate".
2242
2243 config LEGACY_VSYSCALL_NATIVE
2244 bool "Native"
2245 help
2246 Actual executable code is located in the fixed vsyscall
2247 address mapping, implementing time() efficiently. Since
2248 this makes the mapping executable, it can be used during
2249 security vulnerability exploitation (traditionally as
2250 ROP gadgets). This configuration is not recommended.
2251
2252 config LEGACY_VSYSCALL_EMULATE
2253 bool "Emulate"
2254 help
2255 The kernel traps and emulates calls into the fixed
2256 vsyscall address mapping. This makes the mapping
2257 non-executable, but it still contains known contents,
2258 which could be used in certain rare security vulnerability
2259 exploits. This configuration is recommended when userspace
2260 still uses the vsyscall area.
2261
2262 config LEGACY_VSYSCALL_NONE
2263 bool "None"
2264 help
2265 There will be no vsyscall mapping at all. This will
2266 eliminate any risk of ASLR bypass due to the vsyscall
2267 fixed address mapping. Attempts to use the vsyscalls
2268 will be reported to dmesg, so that either old or
2269 malicious userspace programs can be identified.
2270
2271 endchoice
2272
2273 config CMDLINE_BOOL
2274 bool "Built-in kernel command line"
2275 ---help---
2276 Allow for specifying boot arguments to the kernel at
2277 build time. On some systems (e.g. embedded ones), it is
2278 necessary or convenient to provide some or all of the
2279 kernel boot arguments with the kernel itself (that is,
2280 to not rely on the boot loader to provide them.)
2281
2282 To compile command line arguments into the kernel,
2283 set this option to 'Y', then fill in the
2284 boot arguments in CONFIG_CMDLINE.
2285
2286 Systems with fully functional boot loaders (i.e. non-embedded)
2287 should leave this option set to 'N'.
2288
2289 config CMDLINE
2290 string "Built-in kernel command string"
2291 depends on CMDLINE_BOOL
2292 default ""
2293 ---help---
2294 Enter arguments here that should be compiled into the kernel
2295 image and used at boot time. If the boot loader provides a
2296 command line at boot time, it is appended to this string to
2297 form the full kernel command line, when the system boots.
2298
2299 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2300 change this behavior.
2301
2302 In most cases, the command line (whether built-in or provided
2303 by the boot loader) should specify the device for the root
2304 file system.
2305
2306 config CMDLINE_OVERRIDE
2307 bool "Built-in command line overrides boot loader arguments"
2308 depends on CMDLINE_BOOL
2309 ---help---
2310 Set this option to 'Y' to have the kernel ignore the boot loader
2311 command line, and use ONLY the built-in command line.
2312
2313 This is used to work around broken boot loaders. This should
2314 be set to 'N' under normal conditions.
2315
2316 config MODIFY_LDT_SYSCALL
2317 bool "Enable the LDT (local descriptor table)" if EXPERT
2318 default y
2319 ---help---
2320 Linux can allow user programs to install a per-process x86
2321 Local Descriptor Table (LDT) using the modify_ldt(2) system
2322 call. This is required to run 16-bit or segmented code such as
2323 DOSEMU or some Wine programs. It is also used by some very old
2324 threading libraries.
2325
2326 Enabling this feature adds a small amount of overhead to
2327 context switches and increases the low-level kernel attack
2328 surface. Disabling it removes the modify_ldt(2) system call.
2329
2330 Saying 'N' here may make sense for embedded or server kernels.
2331
2332 source "kernel/livepatch/Kconfig"
2333
2334 endmenu
2335
2336 config ARCH_HAS_ADD_PAGES
2337 def_bool y
2338 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2339
2340 config ARCH_ENABLE_MEMORY_HOTPLUG
2341 def_bool y
2342 depends on X86_64 || (X86_32 && HIGHMEM)
2343
2344 config ARCH_ENABLE_MEMORY_HOTREMOVE
2345 def_bool y
2346 depends on MEMORY_HOTPLUG
2347
2348 config USE_PERCPU_NUMA_NODE_ID
2349 def_bool y
2350 depends on NUMA
2351
2352 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2353 def_bool y
2354 depends on X86_64 || X86_PAE
2355
2356 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2357 def_bool y
2358 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2359
2360 config ARCH_ENABLE_THP_MIGRATION
2361 def_bool y
2362 depends on X86_64 && TRANSPARENT_HUGEPAGE
2363
2364 menu "Power management and ACPI options"
2365
2366 config ARCH_HIBERNATION_HEADER
2367 def_bool y
2368 depends on X86_64 && HIBERNATION
2369
2370 source "kernel/power/Kconfig"
2371
2372 source "drivers/acpi/Kconfig"
2373
2374 source "drivers/sfi/Kconfig"
2375
2376 config X86_APM_BOOT
2377 def_bool y
2378 depends on APM
2379
2380 menuconfig APM
2381 tristate "APM (Advanced Power Management) BIOS support"
2382 depends on X86_32 && PM_SLEEP
2383 ---help---
2384 APM is a BIOS specification for saving power using several different
2385 techniques. This is mostly useful for battery powered laptops with
2386 APM compliant BIOSes. If you say Y here, the system time will be
2387 reset after a RESUME operation, the /proc/apm device will provide
2388 battery status information, and user-space programs will receive
2389 notification of APM "events" (e.g. battery status change).
2390
2391 If you select "Y" here, you can disable actual use of the APM
2392 BIOS by passing the "apm=off" option to the kernel at boot time.
2393
2394 Note that the APM support is almost completely disabled for
2395 machines with more than one CPU.
2396
2397 In order to use APM, you will need supporting software. For location
2398 and more information, read <file:Documentation/power/apm-acpi.txt>
2399 and the Battery Powered Linux mini-HOWTO, available from
2400 <http://www.tldp.org/docs.html#howto>.
2401
2402 This driver does not spin down disk drives (see the hdparm(8)
2403 manpage ("man 8 hdparm") for that), and it doesn't turn off
2404 VESA-compliant "green" monitors.
2405
2406 This driver does not support the TI 4000M TravelMate and the ACER
2407 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2408 desktop machines also don't have compliant BIOSes, and this driver
2409 may cause those machines to panic during the boot phase.
2410
2411 Generally, if you don't have a battery in your machine, there isn't
2412 much point in using this driver and you should say N. If you get
2413 random kernel OOPSes or reboots that don't seem to be related to
2414 anything, try disabling/enabling this option (or disabling/enabling
2415 APM in your BIOS).
2416
2417 Some other things you should try when experiencing seemingly random,
2418 "weird" problems:
2419
2420 1) make sure that you have enough swap space and that it is
2421 enabled.
2422 2) pass the "no-hlt" option to the kernel
2423 3) switch on floating point emulation in the kernel and pass
2424 the "no387" option to the kernel
2425 4) pass the "floppy=nodma" option to the kernel
2426 5) pass the "mem=4M" option to the kernel (thereby disabling
2427 all but the first 4 MB of RAM)
2428 6) make sure that the CPU is not over clocked.
2429 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2430 8) disable the cache from your BIOS settings
2431 9) install a fan for the video card or exchange video RAM
2432 10) install a better fan for the CPU
2433 11) exchange RAM chips
2434 12) exchange the motherboard.
2435
2436 To compile this driver as a module, choose M here: the
2437 module will be called apm.
2438
2439 if APM
2440
2441 config APM_IGNORE_USER_SUSPEND
2442 bool "Ignore USER SUSPEND"
2443 ---help---
2444 This option will ignore USER SUSPEND requests. On machines with a
2445 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2446 series notebooks, it is necessary to say Y because of a BIOS bug.
2447
2448 config APM_DO_ENABLE
2449 bool "Enable PM at boot time"
2450 ---help---
2451 Enable APM features at boot time. From page 36 of the APM BIOS
2452 specification: "When disabled, the APM BIOS does not automatically
2453 power manage devices, enter the Standby State, enter the Suspend
2454 State, or take power saving steps in response to CPU Idle calls."
2455 This driver will make CPU Idle calls when Linux is idle (unless this
2456 feature is turned off -- see "Do CPU IDLE calls", below). This
2457 should always save battery power, but more complicated APM features
2458 will be dependent on your BIOS implementation. You may need to turn
2459 this option off if your computer hangs at boot time when using APM
2460 support, or if it beeps continuously instead of suspending. Turn
2461 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2462 T400CDT. This is off by default since most machines do fine without
2463 this feature.
2464
2465 config APM_CPU_IDLE
2466 depends on CPU_IDLE
2467 bool "Make CPU Idle calls when idle"
2468 ---help---
2469 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2470 On some machines, this can activate improved power savings, such as
2471 a slowed CPU clock rate, when the machine is idle. These idle calls
2472 are made after the idle loop has run for some length of time (e.g.,
2473 333 mS). On some machines, this will cause a hang at boot time or
2474 whenever the CPU becomes idle. (On machines with more than one CPU,
2475 this option does nothing.)
2476
2477 config APM_DISPLAY_BLANK
2478 bool "Enable console blanking using APM"
2479 ---help---
2480 Enable console blanking using the APM. Some laptops can use this to
2481 turn off the LCD backlight when the screen blanker of the Linux
2482 virtual console blanks the screen. Note that this is only used by
2483 the virtual console screen blanker, and won't turn off the backlight
2484 when using the X Window system. This also doesn't have anything to
2485 do with your VESA-compliant power-saving monitor. Further, this
2486 option doesn't work for all laptops -- it might not turn off your
2487 backlight at all, or it might print a lot of errors to the console,
2488 especially if you are using gpm.
2489
2490 config APM_ALLOW_INTS
2491 bool "Allow interrupts during APM BIOS calls"
2492 ---help---
2493 Normally we disable external interrupts while we are making calls to
2494 the APM BIOS as a measure to lessen the effects of a badly behaving
2495 BIOS implementation. The BIOS should reenable interrupts if it
2496 needs to. Unfortunately, some BIOSes do not -- especially those in
2497 many of the newer IBM Thinkpads. If you experience hangs when you
2498 suspend, try setting this to Y. Otherwise, say N.
2499
2500 endif # APM
2501
2502 source "drivers/cpufreq/Kconfig"
2503
2504 source "drivers/cpuidle/Kconfig"
2505
2506 source "drivers/idle/Kconfig"
2507
2508 endmenu
2509
2510
2511 menu "Bus options (PCI etc.)"
2512
2513 config PCI
2514 bool "PCI support"
2515 default y
2516 ---help---
2517 Find out whether you have a PCI motherboard. PCI is the name of a
2518 bus system, i.e. the way the CPU talks to the other stuff inside
2519 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2520 VESA. If you have PCI, say Y, otherwise N.
2521
2522 choice
2523 prompt "PCI access mode"
2524 depends on X86_32 && PCI
2525 default PCI_GOANY
2526 ---help---
2527 On PCI systems, the BIOS can be used to detect the PCI devices and
2528 determine their configuration. However, some old PCI motherboards
2529 have BIOS bugs and may crash if this is done. Also, some embedded
2530 PCI-based systems don't have any BIOS at all. Linux can also try to
2531 detect the PCI hardware directly without using the BIOS.
2532
2533 With this option, you can specify how Linux should detect the
2534 PCI devices. If you choose "BIOS", the BIOS will be used,
2535 if you choose "Direct", the BIOS won't be used, and if you
2536 choose "MMConfig", then PCI Express MMCONFIG will be used.
2537 If you choose "Any", the kernel will try MMCONFIG, then the
2538 direct access method and falls back to the BIOS if that doesn't
2539 work. If unsure, go with the default, which is "Any".
2540
2541 config PCI_GOBIOS
2542 bool "BIOS"
2543
2544 config PCI_GOMMCONFIG
2545 bool "MMConfig"
2546
2547 config PCI_GODIRECT
2548 bool "Direct"
2549
2550 config PCI_GOOLPC
2551 bool "OLPC XO-1"
2552 depends on OLPC
2553
2554 config PCI_GOANY
2555 bool "Any"
2556
2557 endchoice
2558
2559 config PCI_BIOS
2560 def_bool y
2561 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2562
2563 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2564 config PCI_DIRECT
2565 def_bool y
2566 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2567
2568 config PCI_MMCONFIG
2569 def_bool y
2570 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2571
2572 config PCI_OLPC
2573 def_bool y
2574 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2575
2576 config PCI_XEN
2577 def_bool y
2578 depends on PCI && XEN
2579 select SWIOTLB_XEN
2580
2581 config PCI_DOMAINS
2582 def_bool y
2583 depends on PCI
2584
2585 config PCI_MMCONFIG
2586 bool "Support mmconfig PCI config space access"
2587 depends on X86_64 && PCI && ACPI
2588
2589 config PCI_CNB20LE_QUIRK
2590 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2591 depends on PCI
2592 help
2593 Read the PCI windows out of the CNB20LE host bridge. This allows
2594 PCI hotplug to work on systems with the CNB20LE chipset which do
2595 not have ACPI.
2596
2597 There's no public spec for this chipset, and this functionality
2598 is known to be incomplete.
2599
2600 You should say N unless you know you need this.
2601
2602 source "drivers/pci/Kconfig"
2603
2604 config ISA_BUS
2605 bool "ISA-style bus support on modern systems" if EXPERT
2606 select ISA_BUS_API
2607 help
2608 Enables ISA-style drivers on modern systems. This is necessary to
2609 support PC/104 devices on X86_64 platforms.
2610
2611 If unsure, say N.
2612
2613 # x86_64 have no ISA slots, but can have ISA-style DMA.
2614 config ISA_DMA_API
2615 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2616 default y
2617 help
2618 Enables ISA-style DMA support for devices requiring such controllers.
2619 If unsure, say Y.
2620
2621 if X86_32
2622
2623 config ISA
2624 bool "ISA support"
2625 ---help---
2626 Find out whether you have ISA slots on your motherboard. ISA is the
2627 name of a bus system, i.e. the way the CPU talks to the other stuff
2628 inside your box. Other bus systems are PCI, EISA, MicroChannel
2629 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2630 newer boards don't support it. If you have ISA, say Y, otherwise N.
2631
2632 config EISA
2633 bool "EISA support"
2634 depends on ISA
2635 ---help---
2636 The Extended Industry Standard Architecture (EISA) bus was
2637 developed as an open alternative to the IBM MicroChannel bus.
2638
2639 The EISA bus provided some of the features of the IBM MicroChannel
2640 bus while maintaining backward compatibility with cards made for
2641 the older ISA bus. The EISA bus saw limited use between 1988 and
2642 1995 when it was made obsolete by the PCI bus.
2643
2644 Say Y here if you are building a kernel for an EISA-based machine.
2645
2646 Otherwise, say N.
2647
2648 source "drivers/eisa/Kconfig"
2649
2650 config SCx200
2651 tristate "NatSemi SCx200 support"
2652 ---help---
2653 This provides basic support for National Semiconductor's
2654 (now AMD's) Geode processors. The driver probes for the
2655 PCI-IDs of several on-chip devices, so its a good dependency
2656 for other scx200_* drivers.
2657
2658 If compiled as a module, the driver is named scx200.
2659
2660 config SCx200HR_TIMER
2661 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2662 depends on SCx200
2663 default y
2664 ---help---
2665 This driver provides a clocksource built upon the on-chip
2666 27MHz high-resolution timer. Its also a workaround for
2667 NSC Geode SC-1100's buggy TSC, which loses time when the
2668 processor goes idle (as is done by the scheduler). The
2669 other workaround is idle=poll boot option.
2670
2671 config OLPC
2672 bool "One Laptop Per Child support"
2673 depends on !X86_PAE
2674 select GPIOLIB
2675 select OF
2676 select OF_PROMTREE
2677 select IRQ_DOMAIN
2678 ---help---
2679 Add support for detecting the unique features of the OLPC
2680 XO hardware.
2681
2682 config OLPC_XO1_PM
2683 bool "OLPC XO-1 Power Management"
2684 depends on OLPC && MFD_CS5535 && PM_SLEEP
2685 select MFD_CORE
2686 ---help---
2687 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2688
2689 config OLPC_XO1_RTC
2690 bool "OLPC XO-1 Real Time Clock"
2691 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2692 ---help---
2693 Add support for the XO-1 real time clock, which can be used as a
2694 programmable wakeup source.
2695
2696 config OLPC_XO1_SCI
2697 bool "OLPC XO-1 SCI extras"
2698 depends on OLPC && OLPC_XO1_PM
2699 depends on INPUT=y
2700 select POWER_SUPPLY
2701 select GPIO_CS5535
2702 select MFD_CORE
2703 ---help---
2704 Add support for SCI-based features of the OLPC XO-1 laptop:
2705 - EC-driven system wakeups
2706 - Power button
2707 - Ebook switch
2708 - Lid switch
2709 - AC adapter status updates
2710 - Battery status updates
2711
2712 config OLPC_XO15_SCI
2713 bool "OLPC XO-1.5 SCI extras"
2714 depends on OLPC && ACPI
2715 select POWER_SUPPLY
2716 ---help---
2717 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2718 - EC-driven system wakeups
2719 - AC adapter status updates
2720 - Battery status updates
2721
2722 config ALIX
2723 bool "PCEngines ALIX System Support (LED setup)"
2724 select GPIOLIB
2725 ---help---
2726 This option enables system support for the PCEngines ALIX.
2727 At present this just sets up LEDs for GPIO control on
2728 ALIX2/3/6 boards. However, other system specific setup should
2729 get added here.
2730
2731 Note: You must still enable the drivers for GPIO and LED support
2732 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2733
2734 Note: You have to set alix.force=1 for boards with Award BIOS.
2735
2736 config NET5501
2737 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2738 select GPIOLIB
2739 ---help---
2740 This option enables system support for the Soekris Engineering net5501.
2741
2742 config GEOS
2743 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2744 select GPIOLIB
2745 depends on DMI
2746 ---help---
2747 This option enables system support for the Traverse Technologies GEOS.
2748
2749 config TS5500
2750 bool "Technologic Systems TS-5500 platform support"
2751 depends on MELAN
2752 select CHECK_SIGNATURE
2753 select NEW_LEDS
2754 select LEDS_CLASS
2755 ---help---
2756 This option enables system support for the Technologic Systems TS-5500.
2757
2758 endif # X86_32
2759
2760 config AMD_NB
2761 def_bool y
2762 depends on CPU_SUP_AMD && PCI
2763
2764 source "drivers/pcmcia/Kconfig"
2765
2766 config RAPIDIO
2767 tristate "RapidIO support"
2768 depends on PCI
2769 default n
2770 help
2771 If enabled this option will include drivers and the core
2772 infrastructure code to support RapidIO interconnect devices.
2773
2774 source "drivers/rapidio/Kconfig"
2775
2776 config X86_SYSFB
2777 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2778 help
2779 Firmwares often provide initial graphics framebuffers so the BIOS,
2780 bootloader or kernel can show basic video-output during boot for
2781 user-guidance and debugging. Historically, x86 used the VESA BIOS
2782 Extensions and EFI-framebuffers for this, which are mostly limited
2783 to x86.
2784 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2785 framebuffers so the new generic system-framebuffer drivers can be
2786 used on x86. If the framebuffer is not compatible with the generic
2787 modes, it is adverticed as fallback platform framebuffer so legacy
2788 drivers like efifb, vesafb and uvesafb can pick it up.
2789 If this option is not selected, all system framebuffers are always
2790 marked as fallback platform framebuffers as usual.
2791
2792 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2793 not be able to pick up generic system framebuffers if this option
2794 is selected. You are highly encouraged to enable simplefb as
2795 replacement if you select this option. simplefb can correctly deal
2796 with generic system framebuffers. But you should still keep vesafb
2797 and others enabled as fallback if a system framebuffer is
2798 incompatible with simplefb.
2799
2800 If unsure, say Y.
2801
2802 endmenu
2803
2804
2805 menu "Executable file formats / Emulations"
2806
2807 source "fs/Kconfig.binfmt"
2808
2809 config IA32_EMULATION
2810 bool "IA32 Emulation"
2811 depends on X86_64
2812 select ARCH_WANT_OLD_COMPAT_IPC
2813 select BINFMT_ELF
2814 select COMPAT_BINFMT_ELF
2815 select COMPAT_OLD_SIGACTION
2816 ---help---
2817 Include code to run legacy 32-bit programs under a
2818 64-bit kernel. You should likely turn this on, unless you're
2819 100% sure that you don't have any 32-bit programs left.
2820
2821 config IA32_AOUT
2822 tristate "IA32 a.out support"
2823 depends on IA32_EMULATION
2824 ---help---
2825 Support old a.out binaries in the 32bit emulation.
2826
2827 config X86_X32
2828 bool "x32 ABI for 64-bit mode"
2829 depends on X86_64
2830 ---help---
2831 Include code to run binaries for the x32 native 32-bit ABI
2832 for 64-bit processors. An x32 process gets access to the
2833 full 64-bit register file and wide data path while leaving
2834 pointers at 32 bits for smaller memory footprint.
2835
2836 You will need a recent binutils (2.22 or later) with
2837 elf32_x86_64 support enabled to compile a kernel with this
2838 option set.
2839
2840 config COMPAT_32
2841 def_bool y
2842 depends on IA32_EMULATION || X86_32
2843 select HAVE_UID16
2844 select OLD_SIGSUSPEND3
2845
2846 config COMPAT
2847 def_bool y
2848 depends on IA32_EMULATION || X86_X32
2849
2850 if COMPAT
2851 config COMPAT_FOR_U64_ALIGNMENT
2852 def_bool y
2853
2854 config SYSVIPC_COMPAT
2855 def_bool y
2856 depends on SYSVIPC
2857 endif
2858
2859 endmenu
2860
2861
2862 config HAVE_ATOMIC_IOMAP
2863 def_bool y
2864 depends on X86_32
2865
2866 config X86_DEV_DMA_OPS
2867 bool
2868 depends on X86_64 || STA2X11
2869
2870 config X86_DMA_REMAP
2871 bool
2872 depends on STA2X11
2873
2874 config HAVE_GENERIC_GUP
2875 def_bool y
2876
2877 source "net/Kconfig"
2878
2879 source "drivers/Kconfig"
2880
2881 source "drivers/firmware/Kconfig"
2882
2883 source "fs/Kconfig"
2884
2885 source "arch/x86/Kconfig.debug"
2886
2887 source "security/Kconfig"
2888
2889 source "crypto/Kconfig"
2890
2891 source "arch/x86/kvm/Kconfig"
2892
2893 source "lib/Kconfig"