blob: c55870ac907ebcbbb08e019a5c19587b3825ec5e [file] [log] [blame]
rjw1f884582022-01-06 17:20:42 +08001# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 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
10config 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
22config 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#
39config 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_CPU_VULNERABILITIES
93 select GENERIC_EARLY_IOREMAP
94 select GENERIC_FIND_FIRST_BIT
95 select GENERIC_IOMAP
96 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
97 select GENERIC_IRQ_MIGRATION if SMP
98 select GENERIC_IRQ_PROBE
99 select GENERIC_IRQ_SHOW
100 select GENERIC_PENDING_IRQ if SMP
101 select GENERIC_SMP_IDLE_THREAD
102 select GENERIC_STRNCPY_FROM_USER
103 select GENERIC_STRNLEN_USER
104 select GENERIC_TIME_VSYSCALL
105 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
106 select HAVE_ACPI_APEI if ACPI
107 select HAVE_ACPI_APEI_NMI if ACPI
108 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
109 select HAVE_ARCH_AUDITSYSCALL
110 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
111 select HAVE_ARCH_JUMP_LABEL
112 select HAVE_ARCH_KASAN if X86_64
113 select HAVE_ARCH_KGDB
114 select HAVE_ARCH_MMAP_RND_BITS if MMU
115 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
116 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
117 select HAVE_ARCH_SECCOMP_FILTER
118 select HAVE_ARCH_TRACEHOOK
119 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
120 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
121 select HAVE_ARCH_VMAP_STACK if X86_64
122 select HAVE_ARCH_WITHIN_STACK_FRAMES
123 select HAVE_CC_STACKPROTECTOR
124 select HAVE_CMPXCHG_DOUBLE
125 select HAVE_CMPXCHG_LOCAL
126 select HAVE_CONTEXT_TRACKING if X86_64
127 select HAVE_COPY_THREAD_TLS
128 select HAVE_C_RECORDMCOUNT
129 select HAVE_DEBUG_KMEMLEAK
130 select HAVE_DEBUG_STACKOVERFLOW
131 select HAVE_DMA_API_DEBUG
132 select HAVE_DMA_CONTIGUOUS
133 select HAVE_DYNAMIC_FTRACE
134 select HAVE_DYNAMIC_FTRACE_WITH_REGS
135 select HAVE_EBPF_JIT if X86_64
136 select HAVE_EFFICIENT_UNALIGNED_ACCESS
137 select HAVE_EXIT_THREAD
138 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
139 select HAVE_FTRACE_MCOUNT_RECORD
140 select HAVE_FUNCTION_GRAPH_TRACER
141 select HAVE_FUNCTION_TRACER
142 select HAVE_GCC_PLUGINS
143 select HAVE_HW_BREAKPOINT
144 select HAVE_IDE
145 select HAVE_IOREMAP_PROT
146 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
147 select HAVE_IRQ_TIME_ACCOUNTING
148 select HAVE_KERNEL_BZIP2
149 select HAVE_KERNEL_GZIP
150 select HAVE_KERNEL_LZ4
151 select HAVE_KERNEL_LZMA
152 select HAVE_KERNEL_LZO
153 select HAVE_KERNEL_XZ
154 select HAVE_KPROBES
155 select HAVE_KPROBES_ON_FTRACE
156 select HAVE_KRETPROBES
157 select HAVE_KVM
158 select HAVE_LIVEPATCH if X86_64
159 select HAVE_MEMBLOCK
160 select HAVE_MEMBLOCK_NODE_MAP
161 select HAVE_MIXED_BREAKPOINTS_REGS
162 select HAVE_MOD_ARCH_SPECIFIC
163 select HAVE_NMI
164 select HAVE_OPROFILE
165 select HAVE_OPTPROBES
166 select HAVE_PCSPKR_PLATFORM
167 select HAVE_PERF_EVENTS
168 select HAVE_PERF_EVENTS_NMI
169 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
170 select HAVE_PERF_REGS
171 select HAVE_PERF_USER_STACK_DUMP
172 select HAVE_RCU_TABLE_FREE
173 select HAVE_RCU_TABLE_INVALIDATE if 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 HOTPLUG_SMT if SMP
181 select IRQ_FORCED_THREADING
182 select PCI_LOCKLESS_CONFIG
183 select PERF_EVENTS
184 select RTC_LIB
185 select RTC_MC146818_LIB
186 select SPARSE_IRQ
187 select SRCU
188 select SYSCTL_EXCEPTION_TRACE
189 select THREAD_INFO_IN_TASK
190 select USER_STACKTRACE_SUPPORT
191 select VIRT_TO_BUS
192 select X86_FEATURE_NAMES if PROC_FS
193
194config INSTRUCTION_DECODER
195 def_bool y
196 depends on KPROBES || PERF_EVENTS || UPROBES
197
198config OUTPUT_FORMAT
199 string
200 default "elf32-i386" if X86_32
201 default "elf64-x86-64" if X86_64
202
203config ARCH_DEFCONFIG
204 string
205 default "arch/x86/configs/i386_defconfig" if X86_32
206 default "arch/x86/configs/x86_64_defconfig" if X86_64
207
208config LOCKDEP_SUPPORT
209 def_bool y
210
211config STACKTRACE_SUPPORT
212 def_bool y
213
214config MMU
215 def_bool y
216
217config ARCH_MMAP_RND_BITS_MIN
218 default 28 if 64BIT
219 default 8
220
221config ARCH_MMAP_RND_BITS_MAX
222 default 32 if 64BIT
223 default 16
224
225config ARCH_MMAP_RND_COMPAT_BITS_MIN
226 default 8
227
228config ARCH_MMAP_RND_COMPAT_BITS_MAX
229 default 16
230
231config SBUS
232 bool
233
234config NEED_DMA_MAP_STATE
235 def_bool y
236 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
237
238config NEED_SG_DMA_LENGTH
239 def_bool y
240
241config GENERIC_ISA_DMA
242 def_bool y
243 depends on ISA_DMA_API
244
245config GENERIC_BUG
246 def_bool y
247 depends on BUG
248 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
249
250config GENERIC_BUG_RELATIVE_POINTERS
251 bool
252
253config GENERIC_HWEIGHT
254 def_bool y
255
256config ARCH_MAY_HAVE_PC_FDC
257 def_bool y
258 depends on ISA_DMA_API
259
260config RWSEM_XCHGADD_ALGORITHM
261 def_bool y
262
263config GENERIC_CALIBRATE_DELAY
264 def_bool y
265
266config ARCH_HAS_CPU_RELAX
267 def_bool y
268
269config ARCH_HAS_CACHE_LINE_SIZE
270 def_bool y
271
272config HAVE_SETUP_PER_CPU_AREA
273 def_bool y
274
275config NEED_PER_CPU_EMBED_FIRST_CHUNK
276 def_bool y
277
278config NEED_PER_CPU_PAGE_FIRST_CHUNK
279 def_bool y
280
281config ARCH_HIBERNATION_POSSIBLE
282 def_bool y
283
284config ARCH_SUSPEND_POSSIBLE
285 def_bool y
286
287config ARCH_WANT_HUGE_PMD_SHARE
288 def_bool y
289
290config ARCH_WANT_GENERAL_HUGETLB
291 def_bool y
292
293config ZONE_DMA32
294 def_bool y if X86_64
295
296config AUDIT_ARCH
297 def_bool y if X86_64
298
299config ARCH_SUPPORTS_OPTIMIZED_INLINING
300 def_bool y
301
302config ARCH_SUPPORTS_DEBUG_PAGEALLOC
303 def_bool y
304
305config KASAN_SHADOW_OFFSET
306 hex
307 depends on KASAN
308 default 0xdffffc0000000000
309
310config HAVE_INTEL_TXT
311 def_bool y
312 depends on INTEL_IOMMU && ACPI
313
314config X86_32_SMP
315 def_bool y
316 depends on X86_32 && SMP
317
318config X86_64_SMP
319 def_bool y
320 depends on X86_64 && SMP
321
322config X86_32_LAZY_GS
323 def_bool y
324 depends on X86_32 && !CC_STACKPROTECTOR
325
326config ARCH_SUPPORTS_UPROBES
327 def_bool y
328
329config FIX_EARLYCON_MEM
330 def_bool y
331
332config PGTABLE_LEVELS
333 int
334 default 5 if X86_5LEVEL
335 default 4 if X86_64
336 default 3 if X86_PAE
337 default 2
338
339source "init/Kconfig"
340source "kernel/Kconfig.freezer"
341
342menu "Processor type and features"
343
344config ZONE_DMA
345 bool "DMA memory allocation support" if EXPERT
346 default y
347 help
348 DMA memory allocation support allows devices with less than 32-bit
349 addressing to allocate within the first 16MB of address space.
350 Disable if no such devices will be used.
351
352 If unsure, say Y.
353
354config SMP
355 bool "Symmetric multi-processing support"
356 ---help---
357 This enables support for systems with more than one CPU. If you have
358 a system with only one CPU, say N. If you have a system with more
359 than one CPU, say Y.
360
361 If you say N here, the kernel will run on uni- and multiprocessor
362 machines, but will use only one CPU of a multiprocessor machine. If
363 you say Y here, the kernel will run on many, but not all,
364 uniprocessor machines. On a uniprocessor machine, the kernel
365 will run faster if you say N here.
366
367 Note that if you say Y here and choose architecture "586" or
368 "Pentium" under "Processor family", the kernel will not work on 486
369 architectures. Similarly, multiprocessor kernels for the "PPro"
370 architecture may not work on all Pentium based boards.
371
372 People using multiprocessor machines who say Y here should also say
373 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
374 Management" code will be disabled if you say Y here.
375
376 See also <file:Documentation/x86/i386/IO-APIC.txt>,
377 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
378 <http://www.tldp.org/docs.html#howto>.
379
380 If you don't know what to do here, say N.
381
382config X86_FEATURE_NAMES
383 bool "Processor feature human-readable names" if EMBEDDED
384 default y
385 ---help---
386 This option compiles in a table of x86 feature bits and corresponding
387 names. This is required to support /proc/cpuinfo and a few kernel
388 messages. You can disable this to save space, at the expense of
389 making those few kernel messages show numeric feature bits instead.
390
391 If in doubt, say Y.
392
393config X86_FAST_FEATURE_TESTS
394 bool "Fast CPU feature tests" if EMBEDDED
395 default y
396 ---help---
397 Some fast-paths in the kernel depend on the capabilities of the CPU.
398 Say Y here for the kernel to patch in the appropriate code at runtime
399 based on the capabilities of the CPU. The infrastructure for patching
400 code at runtime takes up some additional space; space-constrained
401 embedded systems may wish to say N here to produce smaller, slightly
402 slower code.
403
404config X86_X2APIC
405 bool "Support x2apic"
406 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
407 ---help---
408 This enables x2apic support on CPUs that have this feature.
409
410 This allows 32-bit apic IDs (so it can support very large systems),
411 and accesses the local apic via MSRs not via mmio.
412
413 If you don't know what to do here, say N.
414
415config X86_MPPARSE
416 bool "Enable MPS table" if ACPI || SFI
417 default y
418 depends on X86_LOCAL_APIC
419 ---help---
420 For old smp systems that do not have proper acpi support. Newer systems
421 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
422
423config X86_BIGSMP
424 bool "Support for big SMP systems with more than 8 CPUs"
425 depends on X86_32 && SMP
426 ---help---
427 This option is needed for the systems that have more than 8 CPUs
428
429config GOLDFISH
430 def_bool y
431 depends on X86_GOLDFISH
432
433config RETPOLINE
434 bool "Avoid speculative indirect branches in kernel"
435 default y
436 select STACK_VALIDATION if HAVE_STACK_VALIDATION
437 help
438 Compile kernel with the retpoline compiler options to guard against
439 kernel-to-user data leaks by avoiding speculative indirect
440 branches. Requires a compiler with -mindirect-branch=thunk-extern
441 support for full protection. The kernel may run slower.
442
443config INTEL_RDT
444 bool "Intel Resource Director Technology support"
445 default n
446 depends on X86 && CPU_SUP_INTEL
447 select KERNFS
448 help
449 Select to enable resource allocation and monitoring which are
450 sub-features of Intel Resource Director Technology(RDT). More
451 information about RDT can be found in the Intel x86
452 Architecture Software Developer Manual.
453
454 Say N if unsure.
455
456if X86_32
457config X86_EXTENDED_PLATFORM
458 bool "Support for extended (non-PC) x86 platforms"
459 default y
460 ---help---
461 If you disable this option then the kernel will only support
462 standard PC platforms. (which covers the vast majority of
463 systems out there.)
464
465 If you enable this option then you'll be able to select support
466 for the following (non-PC) 32 bit x86 platforms:
467 Goldfish (Android emulator)
468 AMD Elan
469 RDC R-321x SoC
470 SGI 320/540 (Visual Workstation)
471 STA2X11-based (e.g. Northville)
472 Moorestown MID devices
473
474 If you have one of these systems, or if you want to build a
475 generic distribution kernel, say Y here - otherwise say N.
476endif
477
478if X86_64
479config X86_EXTENDED_PLATFORM
480 bool "Support for extended (non-PC) x86 platforms"
481 default y
482 ---help---
483 If you disable this option then the kernel will only support
484 standard PC platforms. (which covers the vast majority of
485 systems out there.)
486
487 If you enable this option then you'll be able to select support
488 for the following (non-PC) 64 bit x86 platforms:
489 Numascale NumaChip
490 ScaleMP vSMP
491 SGI Ultraviolet
492
493 If you have one of these systems, or if you want to build a
494 generic distribution kernel, say Y here - otherwise say N.
495endif
496# This is an alphabetically sorted list of 64 bit extended platforms
497# Please maintain the alphabetic order if and when there are additions
498config X86_NUMACHIP
499 bool "Numascale NumaChip"
500 depends on X86_64
501 depends on X86_EXTENDED_PLATFORM
502 depends on NUMA
503 depends on SMP
504 depends on X86_X2APIC
505 depends on PCI_MMCONFIG
506 ---help---
507 Adds support for Numascale NumaChip large-SMP systems. Needed to
508 enable more than ~168 cores.
509 If you don't have one of these, you should say N here.
510
511config X86_VSMP
512 bool "ScaleMP vSMP"
513 select HYPERVISOR_GUEST
514 select PARAVIRT
515 depends on X86_64 && PCI
516 depends on X86_EXTENDED_PLATFORM
517 depends on SMP
518 ---help---
519 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
520 supposed to run on these EM64T-based machines. Only choose this option
521 if you have one of these machines.
522
523config X86_UV
524 bool "SGI Ultraviolet"
525 depends on X86_64
526 depends on X86_EXTENDED_PLATFORM
527 depends on NUMA
528 depends on EFI
529 depends on X86_X2APIC
530 depends on PCI
531 ---help---
532 This option is needed in order to support SGI Ultraviolet systems.
533 If you don't have one of these, you should say N here.
534
535# Following is an alphabetically sorted list of 32 bit extended platforms
536# Please maintain the alphabetic order if and when there are additions
537
538config X86_GOLDFISH
539 bool "Goldfish (Virtual Platform)"
540 depends on X86_EXTENDED_PLATFORM
541 ---help---
542 Enable support for the Goldfish virtual platform used primarily
543 for Android development. Unless you are building for the Android
544 Goldfish emulator say N here.
545
546config X86_INTEL_CE
547 bool "CE4100 TV platform"
548 depends on PCI
549 depends on PCI_GODIRECT
550 depends on X86_IO_APIC
551 depends on X86_32
552 depends on X86_EXTENDED_PLATFORM
553 select X86_REBOOTFIXUPS
554 select OF
555 select OF_EARLY_FLATTREE
556 ---help---
557 Select for the Intel CE media processor (CE4100) SOC.
558 This option compiles in support for the CE4100 SOC for settop
559 boxes and media devices.
560
561config X86_INTEL_MID
562 bool "Intel MID platform support"
563 depends on X86_EXTENDED_PLATFORM
564 depends on X86_PLATFORM_DEVICES
565 depends on PCI
566 depends on X86_64 || (PCI_GOANY && X86_32)
567 depends on X86_IO_APIC
568 select SFI
569 select I2C
570 select DW_APB_TIMER
571 select APB_TIMER
572 select INTEL_SCU_IPC
573 select MFD_INTEL_MSIC
574 ---help---
575 Select to build a kernel capable of supporting Intel MID (Mobile
576 Internet Device) platform systems which do not have the PCI legacy
577 interfaces. If you are building for a PC class system say N here.
578
579 Intel MID platforms are based on an Intel processor and chipset which
580 consume less power than most of the x86 derivatives.
581
582config X86_INTEL_QUARK
583 bool "Intel Quark platform support"
584 depends on X86_32
585 depends on X86_EXTENDED_PLATFORM
586 depends on X86_PLATFORM_DEVICES
587 depends on X86_TSC
588 depends on PCI
589 depends on PCI_GOANY
590 depends on X86_IO_APIC
591 select IOSF_MBI
592 select INTEL_IMR
593 select COMMON_CLK
594 ---help---
595 Select to include support for Quark X1000 SoC.
596 Say Y here if you have a Quark based system such as the Arduino
597 compatible Intel Galileo.
598
599config X86_INTEL_LPSS
600 bool "Intel Low Power Subsystem Support"
601 depends on X86 && ACPI
602 select COMMON_CLK
603 select PINCTRL
604 select IOSF_MBI
605 ---help---
606 Select to build support for Intel Low Power Subsystem such as
607 found on Intel Lynxpoint PCH. Selecting this option enables
608 things like clock tree (common clock framework) and pincontrol
609 which are needed by the LPSS peripheral drivers.
610
611config X86_AMD_PLATFORM_DEVICE
612 bool "AMD ACPI2Platform devices support"
613 depends on ACPI
614 select COMMON_CLK
615 select PINCTRL
616 ---help---
617 Select to interpret AMD specific ACPI device to platform device
618 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
619 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
620 implemented under PINCTRL subsystem.
621
622config IOSF_MBI
623 tristate "Intel SoC IOSF Sideband support for SoC platforms"
624 depends on PCI
625 ---help---
626 This option enables sideband register access support for Intel SoC
627 platforms. On these platforms the IOSF sideband is used in lieu of
628 MSR's for some register accesses, mostly but not limited to thermal
629 and power. Drivers may query the availability of this device to
630 determine if they need the sideband in order to work on these
631 platforms. The sideband is available on the following SoC products.
632 This list is not meant to be exclusive.
633 - BayTrail
634 - Braswell
635 - Quark
636
637 You should say Y if you are running a kernel on one of these SoC's.
638
639config IOSF_MBI_DEBUG
640 bool "Enable IOSF sideband access through debugfs"
641 depends on IOSF_MBI && DEBUG_FS
642 ---help---
643 Select this option to expose the IOSF sideband access registers (MCR,
644 MDR, MCRX) through debugfs to write and read register information from
645 different units on the SoC. This is most useful for obtaining device
646 state information for debug and analysis. As this is a general access
647 mechanism, users of this option would have specific knowledge of the
648 device they want to access.
649
650 If you don't require the option or are in doubt, say N.
651
652config X86_RDC321X
653 bool "RDC R-321x SoC"
654 depends on X86_32
655 depends on X86_EXTENDED_PLATFORM
656 select M486
657 select X86_REBOOTFIXUPS
658 ---help---
659 This option is needed for RDC R-321x system-on-chip, also known
660 as R-8610-(G).
661 If you don't have one of these chips, you should say N here.
662
663config X86_32_NON_STANDARD
664 bool "Support non-standard 32-bit SMP architectures"
665 depends on X86_32 && SMP
666 depends on X86_EXTENDED_PLATFORM
667 ---help---
668 This option compiles in the bigsmp and STA2X11 default
669 subarchitectures. It is intended for a generic binary
670 kernel. If you select them all, kernel will probe it one by
671 one and will fallback to default.
672
673# Alphabetically sorted list of Non standard 32 bit platforms
674
675config X86_SUPPORTS_MEMORY_FAILURE
676 def_bool y
677 # MCE code calls memory_failure():
678 depends on X86_MCE
679 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
680 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
681 depends on X86_64 || !SPARSEMEM
682 select ARCH_SUPPORTS_MEMORY_FAILURE
683
684config STA2X11
685 bool "STA2X11 Companion Chip Support"
686 depends on X86_32_NON_STANDARD && PCI
687 select X86_DEV_DMA_OPS
688 select X86_DMA_REMAP
689 select SWIOTLB
690 select MFD_STA2X11
691 select GPIOLIB
692 default n
693 ---help---
694 This adds support for boards based on the STA2X11 IO-Hub,
695 a.k.a. "ConneXt". The chip is used in place of the standard
696 PC chipset, so all "standard" peripherals are missing. If this
697 option is selected the kernel will still be able to boot on
698 standard PC machines.
699
700config X86_32_IRIS
701 tristate "Eurobraille/Iris poweroff module"
702 depends on X86_32
703 ---help---
704 The Iris machines from EuroBraille do not have APM or ACPI support
705 to shut themselves down properly. A special I/O sequence is
706 needed to do so, which is what this module does at
707 kernel shutdown.
708
709 This is only for Iris machines from EuroBraille.
710
711 If unused, say N.
712
713config SCHED_OMIT_FRAME_POINTER
714 def_bool y
715 prompt "Single-depth WCHAN output"
716 depends on X86
717 ---help---
718 Calculate simpler /proc/<PID>/wchan values. If this option
719 is disabled then wchan values will recurse back to the
720 caller function. This provides more accurate wchan values,
721 at the expense of slightly more scheduling overhead.
722
723 If in doubt, say "Y".
724
725menuconfig HYPERVISOR_GUEST
726 bool "Linux guest support"
727 ---help---
728 Say Y here to enable options for running Linux under various hyper-
729 visors. This option enables basic hypervisor detection and platform
730 setup.
731
732 If you say N, all options in this submenu will be skipped and
733 disabled, and Linux guest support won't be built in.
734
735if HYPERVISOR_GUEST
736
737config PARAVIRT
738 bool "Enable paravirtualization code"
739 ---help---
740 This changes the kernel so it can modify itself when it is run
741 under a hypervisor, potentially improving performance significantly
742 over full virtualization. However, when run without a hypervisor
743 the kernel is theoretically slower and slightly larger.
744
745config PARAVIRT_DEBUG
746 bool "paravirt-ops debugging"
747 depends on PARAVIRT && DEBUG_KERNEL
748 ---help---
749 Enable to debug paravirt_ops internals. Specifically, BUG if
750 a paravirt_op is missing when it is called.
751
752config PARAVIRT_SPINLOCKS
753 bool "Paravirtualization layer for spinlocks"
754 depends on PARAVIRT && SMP
755 ---help---
756 Paravirtualized spinlocks allow a pvops backend to replace the
757 spinlock implementation with something virtualization-friendly
758 (for example, block the virtual CPU rather than spinning).
759
760 It has a minimal impact on native kernels and gives a nice performance
761 benefit on paravirtualized KVM / Xen kernels.
762
763 If you are unsure how to answer this question, answer Y.
764
765config QUEUED_LOCK_STAT
766 bool "Paravirt queued spinlock statistics"
767 depends on PARAVIRT_SPINLOCKS && DEBUG_FS
768 ---help---
769 Enable the collection of statistical data on the slowpath
770 behavior of paravirtualized queued spinlocks and report
771 them on debugfs.
772
773source "arch/x86/xen/Kconfig"
774
775config KVM_GUEST
776 bool "KVM Guest support (including kvmclock)"
777 depends on PARAVIRT
778 select PARAVIRT_CLOCK
779 default y
780 ---help---
781 This option enables various optimizations for running under the KVM
782 hypervisor. It includes a paravirtualized clock, so that instead
783 of relying on a PIT (or probably other) emulation by the
784 underlying device model, the host provides the guest with
785 timing infrastructure such as time of day, and system time
786
787config KVM_DEBUG_FS
788 bool "Enable debug information for KVM Guests in debugfs"
789 depends on KVM_GUEST && DEBUG_FS
790 default n
791 ---help---
792 This option enables collection of various statistics for KVM guest.
793 Statistics are displayed in debugfs filesystem. Enabling this option
794 may incur significant overhead.
795
796config PARAVIRT_TIME_ACCOUNTING
797 bool "Paravirtual steal time accounting"
798 depends on PARAVIRT
799 default n
800 ---help---
801 Select this option to enable fine granularity task steal time
802 accounting. Time spent executing other tasks in parallel with
803 the current vCPU is discounted from the vCPU power. To account for
804 that, there can be a small performance impact.
805
806 If in doubt, say N here.
807
808config PARAVIRT_CLOCK
809 bool
810
811endif #HYPERVISOR_GUEST
812
813config NO_BOOTMEM
814 def_bool y
815
816source "arch/x86/Kconfig.cpu"
817
818config HPET_TIMER
819 def_bool X86_64
820 prompt "HPET Timer Support" if X86_32
821 ---help---
822 Use the IA-PC HPET (High Precision Event Timer) to manage
823 time in preference to the PIT and RTC, if a HPET is
824 present.
825 HPET is the next generation timer replacing legacy 8254s.
826 The HPET provides a stable time base on SMP
827 systems, unlike the TSC, but it is more expensive to access,
828 as it is off-chip. The interface used is documented
829 in the HPET spec, revision 1.
830
831 You can safely choose Y here. However, HPET will only be
832 activated if the platform and the BIOS support this feature.
833 Otherwise the 8254 will be used for timing services.
834
835 Choose N to continue using the legacy 8254 timer.
836
837config HPET_EMULATE_RTC
838 def_bool y
839 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
840
841config APB_TIMER
842 def_bool y if X86_INTEL_MID
843 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
844 select DW_APB_TIMER
845 depends on X86_INTEL_MID && SFI
846 help
847 APB timer is the replacement for 8254, HPET on X86 MID platforms.
848 The APBT provides a stable time base on SMP
849 systems, unlike the TSC, but it is more expensive to access,
850 as it is off-chip. APB timers are always running regardless of CPU
851 C states, they are used as per CPU clockevent device when possible.
852
853# Mark as expert because too many people got it wrong.
854# The code disables itself when not needed.
855config DMI
856 default y
857 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
858 bool "Enable DMI scanning" if EXPERT
859 ---help---
860 Enabled scanning of DMI to identify machine quirks. Say Y
861 here unless you have verified that your setup is not
862 affected by entries in the DMI blacklist. Required by PNP
863 BIOS code.
864
865config GART_IOMMU
866 bool "Old AMD GART IOMMU support"
867 select SWIOTLB
868 depends on X86_64 && PCI && AMD_NB
869 ---help---
870 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
871 GART based hardware IOMMUs.
872
873 The GART supports full DMA access for devices with 32-bit access
874 limitations, on systems with more than 3 GB. This is usually needed
875 for USB, sound, many IDE/SATA chipsets and some other devices.
876
877 Newer systems typically have a modern AMD IOMMU, supported via
878 the CONFIG_AMD_IOMMU=y config option.
879
880 In normal configurations this driver is only active when needed:
881 there's more than 3 GB of memory and the system contains a
882 32-bit limited device.
883
884 If unsure, say Y.
885
886config CALGARY_IOMMU
887 bool "IBM Calgary IOMMU support"
888 select SWIOTLB
889 depends on X86_64 && PCI
890 ---help---
891 Support for hardware IOMMUs in IBM's xSeries x366 and x460
892 systems. Needed to run systems with more than 3GB of memory
893 properly with 32-bit PCI devices that do not support DAC
894 (Double Address Cycle). Calgary also supports bus level
895 isolation, where all DMAs pass through the IOMMU. This
896 prevents them from going anywhere except their intended
897 destination. This catches hard-to-find kernel bugs and
898 mis-behaving drivers and devices that do not use the DMA-API
899 properly to set up their DMA buffers. The IOMMU can be
900 turned off at boot time with the iommu=off parameter.
901 Normally the kernel will make the right choice by itself.
902 If unsure, say Y.
903
904config CALGARY_IOMMU_ENABLED_BY_DEFAULT
905 def_bool y
906 prompt "Should Calgary be enabled by default?"
907 depends on CALGARY_IOMMU
908 ---help---
909 Should Calgary be enabled by default? if you choose 'y', Calgary
910 will be used (if it exists). If you choose 'n', Calgary will not be
911 used even if it exists. If you choose 'n' and would like to use
912 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
913 If unsure, say Y.
914
915# need this always selected by IOMMU for the VIA workaround
916config SWIOTLB
917 def_bool y if X86_64
918 ---help---
919 Support for software bounce buffers used on x86-64 systems
920 which don't have a hardware IOMMU. Using this PCI devices
921 which can only access 32-bits of memory can be used on systems
922 with more than 3 GB of memory.
923 If unsure, say Y.
924
925config IOMMU_HELPER
926 def_bool y
927 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
928
929config MAXSMP
930 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
931 depends on X86_64 && SMP && DEBUG_KERNEL
932 select CPUMASK_OFFSTACK
933 ---help---
934 Enable maximum number of CPUS and NUMA Nodes for this architecture.
935 If unsure, say N.
936
937config NR_CPUS
938 int "Maximum number of CPUs" if SMP && !MAXSMP
939 range 2 8 if SMP && X86_32 && !X86_BIGSMP
940 range 2 64 if SMP && X86_32 && X86_BIGSMP
941 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK && X86_64
942 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
943 default "1" if !SMP
944 default "8192" if MAXSMP
945 default "32" if SMP && X86_BIGSMP
946 default "8" if SMP && X86_32
947 default "64" if SMP
948 ---help---
949 This allows you to specify the maximum number of CPUs which this
950 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
951 supported value is 8192, otherwise the maximum value is 512. The
952 minimum value which makes sense is 2.
953
954 This is purely to save memory - each supported CPU adds
955 approximately eight kilobytes to the kernel image.
956
957config SCHED_SMT
958 def_bool y if SMP
959
960config SCHED_MC
961 def_bool y
962 prompt "Multi-core scheduler support"
963 depends on SMP
964 ---help---
965 Multi-core scheduler support improves the CPU scheduler's decision
966 making when dealing with multi-core CPU chips at a cost of slightly
967 increased overhead in some places. If unsure say N here.
968
969config SCHED_MC_PRIO
970 bool "CPU core priorities scheduler support"
971 depends on SCHED_MC && CPU_SUP_INTEL
972 select X86_INTEL_PSTATE
973 select CPU_FREQ
974 default y
975 ---help---
976 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
977 core ordering determined at manufacturing time, which allows
978 certain cores to reach higher turbo frequencies (when running
979 single threaded workloads) than others.
980
981 Enabling this kernel feature teaches the scheduler about
982 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
983 scheduler's CPU selection logic accordingly, so that higher
984 overall system performance can be achieved.
985
986 This feature will have no effect on CPUs without this feature.
987
988 If unsure say Y here.
989
990source "kernel/Kconfig.preempt"
991
992config UP_LATE_INIT
993 def_bool y
994 depends on !SMP && X86_LOCAL_APIC
995
996config X86_UP_APIC
997 bool "Local APIC support on uniprocessors" if !PCI_MSI
998 default PCI_MSI
999 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1000 ---help---
1001 A local APIC (Advanced Programmable Interrupt Controller) is an
1002 integrated interrupt controller in the CPU. If you have a single-CPU
1003 system which has a processor with a local APIC, you can say Y here to
1004 enable and use it. If you say Y here even though your machine doesn't
1005 have a local APIC, then the kernel will still run with no slowdown at
1006 all. The local APIC supports CPU-generated self-interrupts (timer,
1007 performance counters), and the NMI watchdog which detects hard
1008 lockups.
1009
1010config X86_UP_IOAPIC
1011 bool "IO-APIC support on uniprocessors"
1012 depends on X86_UP_APIC
1013 ---help---
1014 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1015 SMP-capable replacement for PC-style interrupt controllers. Most
1016 SMP systems and many recent uniprocessor systems have one.
1017
1018 If you have a single-CPU system with an IO-APIC, you can say Y here
1019 to use it. If you say Y here even though your machine doesn't have
1020 an IO-APIC, then the kernel will still run with no slowdown at all.
1021
1022config X86_LOCAL_APIC
1023 def_bool y
1024 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1025 select IRQ_DOMAIN_HIERARCHY
1026 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1027
1028config X86_IO_APIC
1029 def_bool y
1030 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1031
1032config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1033 bool "Reroute for broken boot IRQs"
1034 depends on X86_IO_APIC
1035 ---help---
1036 This option enables a workaround that fixes a source of
1037 spurious interrupts. This is recommended when threaded
1038 interrupt handling is used on systems where the generation of
1039 superfluous "boot interrupts" cannot be disabled.
1040
1041 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1042 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1043 kernel does during interrupt handling). On chipsets where this
1044 boot IRQ generation cannot be disabled, this workaround keeps
1045 the original IRQ line masked so that only the equivalent "boot
1046 IRQ" is delivered to the CPUs. The workaround also tells the
1047 kernel to set up the IRQ handler on the boot IRQ line. In this
1048 way only one interrupt is delivered to the kernel. Otherwise
1049 the spurious second interrupt may cause the kernel to bring
1050 down (vital) interrupt lines.
1051
1052 Only affects "broken" chipsets. Interrupt sharing may be
1053 increased on these systems.
1054
1055config X86_MCE
1056 bool "Machine Check / overheating reporting"
1057 select GENERIC_ALLOCATOR
1058 default y
1059 ---help---
1060 Machine Check support allows the processor to notify the
1061 kernel if it detects a problem (e.g. overheating, data corruption).
1062 The action the kernel takes depends on the severity of the problem,
1063 ranging from warning messages to halting the machine.
1064
1065config X86_MCELOG_LEGACY
1066 bool "Support for deprecated /dev/mcelog character device"
1067 depends on X86_MCE
1068 ---help---
1069 Enable support for /dev/mcelog which is needed by the old mcelog
1070 userspace logging daemon. Consider switching to the new generation
1071 rasdaemon solution.
1072
1073config X86_MCE_INTEL
1074 def_bool y
1075 prompt "Intel MCE features"
1076 depends on X86_MCE && X86_LOCAL_APIC
1077 ---help---
1078 Additional support for intel specific MCE features such as
1079 the thermal monitor.
1080
1081config X86_MCE_AMD
1082 def_bool y
1083 prompt "AMD MCE features"
1084 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1085 ---help---
1086 Additional support for AMD specific MCE features such as
1087 the DRAM Error Threshold.
1088
1089config X86_ANCIENT_MCE
1090 bool "Support for old Pentium 5 / WinChip machine checks"
1091 depends on X86_32 && X86_MCE
1092 ---help---
1093 Include support for machine check handling on old Pentium 5 or WinChip
1094 systems. These typically need to be enabled explicitly on the command
1095 line.
1096
1097config X86_MCE_THRESHOLD
1098 depends on X86_MCE_AMD || X86_MCE_INTEL
1099 def_bool y
1100
1101config X86_MCE_INJECT
1102 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1103 tristate "Machine check injector support"
1104 ---help---
1105 Provide support for injecting machine checks for testing purposes.
1106 If you don't know what a machine check is and you don't do kernel
1107 QA it is safe to say n.
1108
1109config X86_THERMAL_VECTOR
1110 def_bool y
1111 depends on X86_MCE_INTEL
1112
1113source "arch/x86/events/Kconfig"
1114
1115config X86_LEGACY_VM86
1116 bool "Legacy VM86 support"
1117 default n
1118 depends on X86_32
1119 ---help---
1120 This option allows user programs to put the CPU into V8086
1121 mode, which is an 80286-era approximation of 16-bit real mode.
1122
1123 Some very old versions of X and/or vbetool require this option
1124 for user mode setting. Similarly, DOSEMU will use it if
1125 available to accelerate real mode DOS programs. However, any
1126 recent version of DOSEMU, X, or vbetool should be fully
1127 functional even without kernel VM86 support, as they will all
1128 fall back to software emulation. Nevertheless, if you are using
1129 a 16-bit DOS program where 16-bit performance matters, vm86
1130 mode might be faster than emulation and you might want to
1131 enable this option.
1132
1133 Note that any app that works on a 64-bit kernel is unlikely to
1134 need this option, as 64-bit kernels don't, and can't, support
1135 V8086 mode. This option is also unrelated to 16-bit protected
1136 mode and is not needed to run most 16-bit programs under Wine.
1137
1138 Enabling this option increases the complexity of the kernel
1139 and slows down exception handling a tiny bit.
1140
1141 If unsure, say N here.
1142
1143config VM86
1144 bool
1145 default X86_LEGACY_VM86
1146
1147config X86_16BIT
1148 bool "Enable support for 16-bit segments" if EXPERT
1149 default y
1150 depends on MODIFY_LDT_SYSCALL
1151 ---help---
1152 This option is required by programs like Wine to run 16-bit
1153 protected mode legacy code on x86 processors. Disabling
1154 this option saves about 300 bytes on i386, or around 6K text
1155 plus 16K runtime memory on x86-64,
1156
1157config X86_ESPFIX32
1158 def_bool y
1159 depends on X86_16BIT && X86_32
1160
1161config X86_ESPFIX64
1162 def_bool y
1163 depends on X86_16BIT && X86_64
1164
1165config X86_VSYSCALL_EMULATION
1166 bool "Enable vsyscall emulation" if EXPERT
1167 default y
1168 depends on X86_64
1169 ---help---
1170 This enables emulation of the legacy vsyscall page. Disabling
1171 it is roughly equivalent to booting with vsyscall=none, except
1172 that it will also disable the helpful warning if a program
1173 tries to use a vsyscall. With this option set to N, offending
1174 programs will just segfault, citing addresses of the form
1175 0xffffffffff600?00.
1176
1177 This option is required by many programs built before 2013, and
1178 care should be used even with newer programs if set to N.
1179
1180 Disabling this option saves about 7K of kernel size and
1181 possibly 4K of additional runtime pagetable memory.
1182
1183config TOSHIBA
1184 tristate "Toshiba Laptop support"
1185 depends on X86_32
1186 ---help---
1187 This adds a driver to safely access the System Management Mode of
1188 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1189 not work on models with a Phoenix BIOS. The System Management Mode
1190 is used to set the BIOS and power saving options on Toshiba portables.
1191
1192 For information on utilities to make use of this driver see the
1193 Toshiba Linux utilities web site at:
1194 <http://www.buzzard.org.uk/toshiba/>.
1195
1196 Say Y if you intend to run this kernel on a Toshiba portable.
1197 Say N otherwise.
1198
1199config I8K
1200 tristate "Dell i8k legacy laptop support"
1201 select HWMON
1202 select SENSORS_DELL_SMM
1203 ---help---
1204 This option enables legacy /proc/i8k userspace interface in hwmon
1205 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1206 temperature and allows controlling fan speeds of Dell laptops via
1207 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1208 it reports also power and hotkey status. For fan speed control is
1209 needed userspace package i8kutils.
1210
1211 Say Y if you intend to run this kernel on old Dell laptops or want to
1212 use userspace package i8kutils.
1213 Say N otherwise.
1214
1215config X86_REBOOTFIXUPS
1216 bool "Enable X86 board specific fixups for reboot"
1217 depends on X86_32
1218 ---help---
1219 This enables chipset and/or board specific fixups to be done
1220 in order to get reboot to work correctly. This is only needed on
1221 some combinations of hardware and BIOS. The symptom, for which
1222 this config is intended, is when reboot ends with a stalled/hung
1223 system.
1224
1225 Currently, the only fixup is for the Geode machines using
1226 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1227
1228 Say Y if you want to enable the fixup. Currently, it's safe to
1229 enable this option even if you don't need it.
1230 Say N otherwise.
1231
1232config MICROCODE
1233 bool "CPU microcode loading support"
1234 default y
1235 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1236 select FW_LOADER
1237 ---help---
1238 If you say Y here, you will be able to update the microcode on
1239 Intel and AMD processors. The Intel support is for the IA32 family,
1240 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1241 AMD support is for families 0x10 and later. You will obviously need
1242 the actual microcode binary data itself which is not shipped with
1243 the Linux kernel.
1244
1245 The preferred method to load microcode from a detached initrd is described
1246 in Documentation/x86/early-microcode.txt. For that you need to enable
1247 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1248 initrd for microcode blobs.
1249
1250 In addition, you can build-in the microcode into the kernel. For that you
1251 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1252 to the CONFIG_EXTRA_FIRMWARE config option.
1253
1254config MICROCODE_INTEL
1255 bool "Intel microcode loading support"
1256 depends on MICROCODE
1257 default MICROCODE
1258 select FW_LOADER
1259 ---help---
1260 This options enables microcode patch loading support for Intel
1261 processors.
1262
1263 For the current Intel microcode data package go to
1264 <https://downloadcenter.intel.com> and search for
1265 'Linux Processor Microcode Data File'.
1266
1267config MICROCODE_AMD
1268 bool "AMD microcode loading support"
1269 depends on MICROCODE
1270 select FW_LOADER
1271 ---help---
1272 If you select this option, microcode patch loading support for AMD
1273 processors will be enabled.
1274
1275config MICROCODE_OLD_INTERFACE
1276 def_bool y
1277 depends on MICROCODE
1278
1279config X86_MSR
1280 tristate "/dev/cpu/*/msr - Model-specific register support"
1281 ---help---
1282 This device gives privileged processes access to the x86
1283 Model-Specific Registers (MSRs). It is a character device with
1284 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1285 MSR accesses are directed to a specific CPU on multi-processor
1286 systems.
1287
1288config X86_CPUID
1289 tristate "/dev/cpu/*/cpuid - CPU information support"
1290 ---help---
1291 This device gives processes access to the x86 CPUID instruction to
1292 be executed on a specific processor. It is a character device
1293 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1294 /dev/cpu/31/cpuid.
1295
1296choice
1297 prompt "High Memory Support"
1298 default HIGHMEM4G
1299 depends on X86_32
1300
1301config NOHIGHMEM
1302 bool "off"
1303 ---help---
1304 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1305 However, the address space of 32-bit x86 processors is only 4
1306 Gigabytes large. That means that, if you have a large amount of
1307 physical memory, not all of it can be "permanently mapped" by the
1308 kernel. The physical memory that's not permanently mapped is called
1309 "high memory".
1310
1311 If you are compiling a kernel which will never run on a machine with
1312 more than 1 Gigabyte total physical RAM, answer "off" here (default
1313 choice and suitable for most users). This will result in a "3GB/1GB"
1314 split: 3GB are mapped so that each process sees a 3GB virtual memory
1315 space and the remaining part of the 4GB virtual memory space is used
1316 by the kernel to permanently map as much physical memory as
1317 possible.
1318
1319 If the machine has between 1 and 4 Gigabytes physical RAM, then
1320 answer "4GB" here.
1321
1322 If more than 4 Gigabytes is used then answer "64GB" here. This
1323 selection turns Intel PAE (Physical Address Extension) mode on.
1324 PAE implements 3-level paging on IA32 processors. PAE is fully
1325 supported by Linux, PAE mode is implemented on all recent Intel
1326 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1327 then the kernel will not boot on CPUs that don't support PAE!
1328
1329 The actual amount of total physical memory will either be
1330 auto detected or can be forced by using a kernel command line option
1331 such as "mem=256M". (Try "man bootparam" or see the documentation of
1332 your boot loader (lilo or loadlin) about how to pass options to the
1333 kernel at boot time.)
1334
1335 If unsure, say "off".
1336
1337config HIGHMEM4G
1338 bool "4GB"
1339 ---help---
1340 Select this if you have a 32-bit processor and between 1 and 4
1341 gigabytes of physical RAM.
1342
1343config HIGHMEM64G
1344 bool "64GB"
1345 depends on !M486
1346 select X86_PAE
1347 ---help---
1348 Select this if you have a 32-bit processor and more than 4
1349 gigabytes of physical RAM.
1350
1351endchoice
1352
1353choice
1354 prompt "Memory split" if EXPERT
1355 default VMSPLIT_3G
1356 depends on X86_32
1357 ---help---
1358 Select the desired split between kernel and user memory.
1359
1360 If the address range available to the kernel is less than the
1361 physical memory installed, the remaining memory will be available
1362 as "high memory". Accessing high memory is a little more costly
1363 than low memory, as it needs to be mapped into the kernel first.
1364 Note that increasing the kernel address space limits the range
1365 available to user programs, making the address space there
1366 tighter. Selecting anything other than the default 3G/1G split
1367 will also likely make your kernel incompatible with binary-only
1368 kernel modules.
1369
1370 If you are not absolutely sure what you are doing, leave this
1371 option alone!
1372
1373 config VMSPLIT_3G
1374 bool "3G/1G user/kernel split"
1375 config VMSPLIT_3G_OPT
1376 depends on !X86_PAE
1377 bool "3G/1G user/kernel split (for full 1G low memory)"
1378 config VMSPLIT_2G
1379 bool "2G/2G user/kernel split"
1380 config VMSPLIT_2G_OPT
1381 depends on !X86_PAE
1382 bool "2G/2G user/kernel split (for full 2G low memory)"
1383 config VMSPLIT_1G
1384 bool "1G/3G user/kernel split"
1385endchoice
1386
1387config PAGE_OFFSET
1388 hex
1389 default 0xB0000000 if VMSPLIT_3G_OPT
1390 default 0x80000000 if VMSPLIT_2G
1391 default 0x78000000 if VMSPLIT_2G_OPT
1392 default 0x40000000 if VMSPLIT_1G
1393 default 0xC0000000
1394 depends on X86_32
1395
1396config HIGHMEM
1397 def_bool y
1398 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1399
1400config X86_PAE
1401 bool "PAE (Physical Address Extension) Support"
1402 depends on X86_32 && !HIGHMEM4G
1403 select SWIOTLB
1404 ---help---
1405 PAE is required for NX support, and furthermore enables
1406 larger swapspace support for non-overcommit purposes. It
1407 has the cost of more pagetable lookup overhead, and also
1408 consumes more pagetable space per process.
1409
1410config X86_5LEVEL
1411 bool "Enable 5-level page tables support"
1412 depends on X86_64
1413 ---help---
1414 5-level paging enables access to larger address space:
1415 upto 128 PiB of virtual address space and 4 PiB of
1416 physical address space.
1417
1418 It will be supported by future Intel CPUs.
1419
1420 Note: a kernel with this option enabled can only be booted
1421 on machines that support the feature.
1422
1423 See Documentation/x86/x86_64/5level-paging.txt for more
1424 information.
1425
1426 Say N if unsure.
1427
1428config ARCH_PHYS_ADDR_T_64BIT
1429 def_bool y
1430 depends on X86_64 || X86_PAE
1431
1432config ARCH_DMA_ADDR_T_64BIT
1433 def_bool y
1434 depends on X86_64 || HIGHMEM64G
1435
1436config X86_DIRECT_GBPAGES
1437 def_bool y
1438 depends on X86_64 && !DEBUG_PAGEALLOC
1439 ---help---
1440 Certain kernel features effectively disable kernel
1441 linear 1 GB mappings (even if the CPU otherwise
1442 supports them), so don't confuse the user by printing
1443 that we have them enabled.
1444
1445config ARCH_HAS_MEM_ENCRYPT
1446 def_bool y
1447
1448config AMD_MEM_ENCRYPT
1449 bool "AMD Secure Memory Encryption (SME) support"
1450 depends on X86_64 && CPU_SUP_AMD
1451 ---help---
1452 Say yes to enable support for the encryption of system memory.
1453 This requires an AMD processor that supports Secure Memory
1454 Encryption (SME).
1455
1456config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1457 bool "Activate AMD Secure Memory Encryption (SME) by default"
1458 default y
1459 depends on AMD_MEM_ENCRYPT
1460 ---help---
1461 Say yes to have system memory encrypted by default if running on
1462 an AMD processor that supports Secure Memory Encryption (SME).
1463
1464 If set to Y, then the encryption of system memory can be
1465 deactivated with the mem_encrypt=off command line option.
1466
1467 If set to N, then the encryption of system memory can be
1468 activated with the mem_encrypt=on command line option.
1469
1470config ARCH_USE_MEMREMAP_PROT
1471 def_bool y
1472 depends on AMD_MEM_ENCRYPT
1473
1474# Common NUMA Features
1475config NUMA
1476 bool "Numa Memory Allocation and Scheduler Support"
1477 depends on SMP
1478 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1479 default y if X86_BIGSMP
1480 ---help---
1481 Enable NUMA (Non Uniform Memory Access) support.
1482
1483 The kernel will try to allocate memory used by a CPU on the
1484 local memory controller of the CPU and add some more
1485 NUMA awareness to the kernel.
1486
1487 For 64-bit this is recommended if the system is Intel Core i7
1488 (or later), AMD Opteron, or EM64T NUMA.
1489
1490 For 32-bit this is only needed if you boot a 32-bit
1491 kernel on a 64-bit NUMA platform.
1492
1493 Otherwise, you should say N.
1494
1495config AMD_NUMA
1496 def_bool y
1497 prompt "Old style AMD Opteron NUMA detection"
1498 depends on X86_64 && NUMA && PCI
1499 ---help---
1500 Enable AMD NUMA node topology detection. You should say Y here if
1501 you have a multi processor AMD system. This uses an old method to
1502 read the NUMA configuration directly from the builtin Northbridge
1503 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1504 which also takes priority if both are compiled in.
1505
1506config X86_64_ACPI_NUMA
1507 def_bool y
1508 prompt "ACPI NUMA detection"
1509 depends on X86_64 && NUMA && ACPI && PCI
1510 select ACPI_NUMA
1511 ---help---
1512 Enable ACPI SRAT based node topology detection.
1513
1514# Some NUMA nodes have memory ranges that span
1515# other nodes. Even though a pfn is valid and
1516# between a node's start and end pfns, it may not
1517# reside on that node. See memmap_init_zone()
1518# for details.
1519config NODES_SPAN_OTHER_NODES
1520 def_bool y
1521 depends on X86_64_ACPI_NUMA
1522
1523config NUMA_EMU
1524 bool "NUMA emulation"
1525 depends on NUMA
1526 ---help---
1527 Enable NUMA emulation. A flat machine will be split
1528 into virtual nodes when booted with "numa=fake=N", where N is the
1529 number of nodes. This is only useful for debugging.
1530
1531config NODES_SHIFT
1532 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1533 range 1 10
1534 default "10" if MAXSMP
1535 default "6" if X86_64
1536 default "3"
1537 depends on NEED_MULTIPLE_NODES
1538 ---help---
1539 Specify the maximum number of NUMA Nodes available on the target
1540 system. Increases memory reserved to accommodate various tables.
1541
1542config ARCH_HAVE_MEMORY_PRESENT
1543 def_bool y
1544 depends on X86_32 && DISCONTIGMEM
1545
1546config NEED_NODE_MEMMAP_SIZE
1547 def_bool y
1548 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1549
1550config ARCH_FLATMEM_ENABLE
1551 def_bool y
1552 depends on X86_32 && !NUMA
1553
1554config ARCH_DISCONTIGMEM_ENABLE
1555 def_bool y
1556 depends on NUMA && X86_32
1557
1558config ARCH_DISCONTIGMEM_DEFAULT
1559 def_bool y
1560 depends on NUMA && X86_32
1561
1562config ARCH_SPARSEMEM_ENABLE
1563 def_bool y
1564 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1565 select SPARSEMEM_STATIC if X86_32
1566 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1567
1568config ARCH_SPARSEMEM_DEFAULT
1569 def_bool y
1570 depends on X86_64
1571
1572config ARCH_SELECT_MEMORY_MODEL
1573 def_bool y
1574 depends on ARCH_SPARSEMEM_ENABLE
1575
1576config ARCH_MEMORY_PROBE
1577 bool "Enable sysfs memory/probe interface"
1578 depends on X86_64 && MEMORY_HOTPLUG
1579 help
1580 This option enables a sysfs memory/probe interface for testing.
1581 See Documentation/memory-hotplug.txt for more information.
1582 If you are unsure how to answer this question, answer N.
1583
1584config ARCH_PROC_KCORE_TEXT
1585 def_bool y
1586 depends on X86_64 && PROC_KCORE
1587
1588config ILLEGAL_POINTER_VALUE
1589 hex
1590 default 0 if X86_32
1591 default 0xdead000000000000 if X86_64
1592
1593source "mm/Kconfig"
1594
1595config X86_PMEM_LEGACY_DEVICE
1596 bool
1597
1598config X86_PMEM_LEGACY
1599 tristate "Support non-standard NVDIMMs and ADR protected memory"
1600 depends on PHYS_ADDR_T_64BIT
1601 depends on BLK_DEV
1602 select X86_PMEM_LEGACY_DEVICE
1603 select LIBNVDIMM
1604 help
1605 Treat memory marked using the non-standard e820 type of 12 as used
1606 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1607 The kernel will offer these regions to the 'pmem' driver so
1608 they can be used for persistent storage.
1609
1610 Say Y if unsure.
1611
1612config HIGHPTE
1613 bool "Allocate 3rd-level pagetables from highmem"
1614 depends on HIGHMEM
1615 ---help---
1616 The VM uses one page table entry for each page of physical memory.
1617 For systems with a lot of RAM, this can be wasteful of precious
1618 low memory. Setting this option will put user-space page table
1619 entries in high memory.
1620
1621config X86_CHECK_BIOS_CORRUPTION
1622 bool "Check for low memory corruption"
1623 ---help---
1624 Periodically check for memory corruption in low memory, which
1625 is suspected to be caused by BIOS. Even when enabled in the
1626 configuration, it is disabled at runtime. Enable it by
1627 setting "memory_corruption_check=1" on the kernel command
1628 line. By default it scans the low 64k of memory every 60
1629 seconds; see the memory_corruption_check_size and
1630 memory_corruption_check_period parameters in
1631 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1632
1633 When enabled with the default parameters, this option has
1634 almost no overhead, as it reserves a relatively small amount
1635 of memory and scans it infrequently. It both detects corruption
1636 and prevents it from affecting the running system.
1637
1638 It is, however, intended as a diagnostic tool; if repeatable
1639 BIOS-originated corruption always affects the same memory,
1640 you can use memmap= to prevent the kernel from using that
1641 memory.
1642
1643config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1644 bool "Set the default setting of memory_corruption_check"
1645 depends on X86_CHECK_BIOS_CORRUPTION
1646 default y
1647 ---help---
1648 Set whether the default state of memory_corruption_check is
1649 on or off.
1650
1651config X86_RESERVE_LOW
1652 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1653 default 64
1654 range 4 640
1655 ---help---
1656 Specify the amount of low memory to reserve for the BIOS.
1657
1658 The first page contains BIOS data structures that the kernel
1659 must not use, so that page must always be reserved.
1660
1661 By default we reserve the first 64K of physical RAM, as a
1662 number of BIOSes are known to corrupt that memory range
1663 during events such as suspend/resume or monitor cable
1664 insertion, so it must not be used by the kernel.
1665
1666 You can set this to 4 if you are absolutely sure that you
1667 trust the BIOS to get all its memory reservations and usages
1668 right. If you know your BIOS have problems beyond the
1669 default 64K area, you can set this to 640 to avoid using the
1670 entire low memory range.
1671
1672 If you have doubts about the BIOS (e.g. suspend/resume does
1673 not work or there's kernel crashes after certain hardware
1674 hotplug events) then you might want to enable
1675 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1676 typical corruption patterns.
1677
1678 Leave this to the default value of 64 if you are unsure.
1679
1680config MATH_EMULATION
1681 bool
1682 depends on MODIFY_LDT_SYSCALL
1683 prompt "Math emulation" if X86_32
1684 ---help---
1685 Linux can emulate a math coprocessor (used for floating point
1686 operations) if you don't have one. 486DX and Pentium processors have
1687 a math coprocessor built in, 486SX and 386 do not, unless you added
1688 a 487DX or 387, respectively. (The messages during boot time can
1689 give you some hints here ["man dmesg"].) Everyone needs either a
1690 coprocessor or this emulation.
1691
1692 If you don't have a math coprocessor, you need to say Y here; if you
1693 say Y here even though you have a coprocessor, the coprocessor will
1694 be used nevertheless. (This behavior can be changed with the kernel
1695 command line option "no387", which comes handy if your coprocessor
1696 is broken. Try "man bootparam" or see the documentation of your boot
1697 loader (lilo or loadlin) about how to pass options to the kernel at
1698 boot time.) This means that it is a good idea to say Y here if you
1699 intend to use this kernel on different machines.
1700
1701 More information about the internals of the Linux math coprocessor
1702 emulation can be found in <file:arch/x86/math-emu/README>.
1703
1704 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1705 kernel, it won't hurt.
1706
1707config MTRR
1708 def_bool y
1709 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1710 ---help---
1711 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1712 the Memory Type Range Registers (MTRRs) may be used to control
1713 processor access to memory ranges. This is most useful if you have
1714 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1715 allows bus write transfers to be combined into a larger transfer
1716 before bursting over the PCI/AGP bus. This can increase performance
1717 of image write operations 2.5 times or more. Saying Y here creates a
1718 /proc/mtrr file which may be used to manipulate your processor's
1719 MTRRs. Typically the X server should use this.
1720
1721 This code has a reasonably generic interface so that similar
1722 control registers on other processors can be easily supported
1723 as well:
1724
1725 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1726 Registers (ARRs) which provide a similar functionality to MTRRs. For
1727 these, the ARRs are used to emulate the MTRRs.
1728 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1729 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1730 write-combining. All of these processors are supported by this code
1731 and it makes sense to say Y here if you have one of them.
1732
1733 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1734 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1735 can lead to all sorts of problems, so it's good to say Y here.
1736
1737 You can safely say Y even if your machine doesn't have MTRRs, you'll
1738 just add about 9 KB to your kernel.
1739
1740 See <file:Documentation/x86/mtrr.txt> for more information.
1741
1742config MTRR_SANITIZER
1743 def_bool y
1744 prompt "MTRR cleanup support"
1745 depends on MTRR
1746 ---help---
1747 Convert MTRR layout from continuous to discrete, so X drivers can
1748 add writeback entries.
1749
1750 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1751 The largest mtrr entry size for a continuous block can be set with
1752 mtrr_chunk_size.
1753
1754 If unsure, say Y.
1755
1756config MTRR_SANITIZER_ENABLE_DEFAULT
1757 int "MTRR cleanup enable value (0-1)"
1758 range 0 1
1759 default "0"
1760 depends on MTRR_SANITIZER
1761 ---help---
1762 Enable mtrr cleanup default value
1763
1764config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1765 int "MTRR cleanup spare reg num (0-7)"
1766 range 0 7
1767 default "1"
1768 depends on MTRR_SANITIZER
1769 ---help---
1770 mtrr cleanup spare entries default, it can be changed via
1771 mtrr_spare_reg_nr=N on the kernel command line.
1772
1773config X86_PAT
1774 def_bool y
1775 prompt "x86 PAT support" if EXPERT
1776 depends on MTRR
1777 ---help---
1778 Use PAT attributes to setup page level cache control.
1779
1780 PATs are the modern equivalents of MTRRs and are much more
1781 flexible than MTRRs.
1782
1783 Say N here if you see bootup problems (boot crash, boot hang,
1784 spontaneous reboots) or a non-working video driver.
1785
1786 If unsure, say Y.
1787
1788config ARCH_USES_PG_UNCACHED
1789 def_bool y
1790 depends on X86_PAT
1791
1792config ARCH_RANDOM
1793 def_bool y
1794 prompt "x86 architectural random number generator" if EXPERT
1795 ---help---
1796 Enable the x86 architectural RDRAND instruction
1797 (Intel Bull Mountain technology) to generate random numbers.
1798 If supported, this is a high bandwidth, cryptographically
1799 secure hardware random number generator.
1800
1801config X86_SMAP
1802 def_bool y
1803 prompt "Supervisor Mode Access Prevention" if EXPERT
1804 ---help---
1805 Supervisor Mode Access Prevention (SMAP) is a security
1806 feature in newer Intel processors. There is a small
1807 performance cost if this enabled and turned on; there is
1808 also a small increase in the kernel size if this is enabled.
1809
1810 If unsure, say Y.
1811
1812config X86_INTEL_MPX
1813 prompt "Intel MPX (Memory Protection Extensions)"
1814 def_bool n
1815 # Note: only available in 64-bit mode due to VMA flags shortage
1816 depends on CPU_SUP_INTEL && X86_64
1817 select ARCH_USES_HIGH_VMA_FLAGS
1818 ---help---
1819 MPX provides hardware features that can be used in
1820 conjunction with compiler-instrumented code to check
1821 memory references. It is designed to detect buffer
1822 overflow or underflow bugs.
1823
1824 This option enables running applications which are
1825 instrumented or otherwise use MPX. It does not use MPX
1826 itself inside the kernel or to protect the kernel
1827 against bad memory references.
1828
1829 Enabling this option will make the kernel larger:
1830 ~8k of kernel text and 36 bytes of data on a 64-bit
1831 defconfig. It adds a long to the 'mm_struct' which
1832 will increase the kernel memory overhead of each
1833 process and adds some branches to paths used during
1834 exec() and munmap().
1835
1836 For details, see Documentation/x86/intel_mpx.txt
1837
1838 If unsure, say N.
1839
1840config X86_INTEL_MEMORY_PROTECTION_KEYS
1841 prompt "Intel Memory Protection Keys"
1842 def_bool y
1843 # Note: only available in 64-bit mode
1844 depends on CPU_SUP_INTEL && X86_64
1845 select ARCH_USES_HIGH_VMA_FLAGS
1846 select ARCH_HAS_PKEYS
1847 ---help---
1848 Memory Protection Keys provides a mechanism for enforcing
1849 page-based protections, but without requiring modification of the
1850 page tables when an application changes protection domains.
1851
1852 For details, see Documentation/x86/protection-keys.txt
1853
1854 If unsure, say y.
1855
1856choice
1857 prompt "TSX enable mode"
1858 depends on CPU_SUP_INTEL
1859 default X86_INTEL_TSX_MODE_OFF
1860 help
1861 Intel's TSX (Transactional Synchronization Extensions) feature
1862 allows to optimize locking protocols through lock elision which
1863 can lead to a noticeable performance boost.
1864
1865 On the other hand it has been shown that TSX can be exploited
1866 to form side channel attacks (e.g. TAA) and chances are there
1867 will be more of those attacks discovered in the future.
1868
1869 Therefore TSX is not enabled by default (aka tsx=off). An admin
1870 might override this decision by tsx=on the command line parameter.
1871 Even with TSX enabled, the kernel will attempt to enable the best
1872 possible TAA mitigation setting depending on the microcode available
1873 for the particular machine.
1874
1875 This option allows to set the default tsx mode between tsx=on, =off
1876 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1877 details.
1878
1879 Say off if not sure, auto if TSX is in use but it should be used on safe
1880 platforms or on if TSX is in use and the security aspect of tsx is not
1881 relevant.
1882
1883config X86_INTEL_TSX_MODE_OFF
1884 bool "off"
1885 help
1886 TSX is disabled if possible - equals to tsx=off command line parameter.
1887
1888config X86_INTEL_TSX_MODE_ON
1889 bool "on"
1890 help
1891 TSX is always enabled on TSX capable HW - equals the tsx=on command
1892 line parameter.
1893
1894config X86_INTEL_TSX_MODE_AUTO
1895 bool "auto"
1896 help
1897 TSX is enabled on TSX capable HW that is believed to be safe against
1898 side channel attacks- equals the tsx=auto command line parameter.
1899endchoice
1900
1901config EFI
1902 bool "EFI runtime service support"
1903 depends on ACPI
1904 select UCS2_STRING
1905 select EFI_RUNTIME_WRAPPERS
1906 ---help---
1907 This enables the kernel to use EFI runtime services that are
1908 available (such as the EFI variable services).
1909
1910 This option is only useful on systems that have EFI firmware.
1911 In addition, you should use the latest ELILO loader available
1912 at <http://elilo.sourceforge.net> in order to take advantage
1913 of EFI runtime services. However, even with this option, the
1914 resultant kernel should continue to boot on existing non-EFI
1915 platforms.
1916
1917config EFI_STUB
1918 bool "EFI stub support"
1919 depends on EFI && !X86_USE_3DNOW
1920 select RELOCATABLE
1921 ---help---
1922 This kernel feature allows a bzImage to be loaded directly
1923 by EFI firmware without the use of a bootloader.
1924
1925 See Documentation/efi-stub.txt for more information.
1926
1927config EFI_MIXED
1928 bool "EFI mixed-mode support"
1929 depends on EFI_STUB && X86_64
1930 ---help---
1931 Enabling this feature allows a 64-bit kernel to be booted
1932 on a 32-bit firmware, provided that your CPU supports 64-bit
1933 mode.
1934
1935 Note that it is not possible to boot a mixed-mode enabled
1936 kernel via the EFI boot stub - a bootloader that supports
1937 the EFI handover protocol must be used.
1938
1939 If unsure, say N.
1940
1941config SECCOMP
1942 def_bool y
1943 prompt "Enable seccomp to safely compute untrusted bytecode"
1944 ---help---
1945 This kernel feature is useful for number crunching applications
1946 that may need to compute untrusted bytecode during their
1947 execution. By using pipes or other transports made available to
1948 the process as file descriptors supporting the read/write
1949 syscalls, it's possible to isolate those applications in
1950 their own address space using seccomp. Once seccomp is
1951 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1952 and the task is only allowed to execute a few safe syscalls
1953 defined by each seccomp mode.
1954
1955 If unsure, say Y. Only embedded should say N here.
1956
1957source kernel/Kconfig.hz
1958
1959config KEXEC
1960 bool "kexec system call"
1961 select KEXEC_CORE
1962 ---help---
1963 kexec is a system call that implements the ability to shutdown your
1964 current kernel, and to start another kernel. It is like a reboot
1965 but it is independent of the system firmware. And like a reboot
1966 you can start any kernel with it, not just Linux.
1967
1968 The name comes from the similarity to the exec system call.
1969
1970 It is an ongoing process to be certain the hardware in a machine
1971 is properly shutdown, so do not be surprised if this code does not
1972 initially work for you. As of this writing the exact hardware
1973 interface is strongly in flux, so no good recommendation can be
1974 made.
1975
1976config KEXEC_FILE
1977 bool "kexec file based system call"
1978 select KEXEC_CORE
1979 select BUILD_BIN2C
1980 depends on X86_64
1981 depends on CRYPTO=y
1982 depends on CRYPTO_SHA256=y
1983 ---help---
1984 This is new version of kexec system call. This system call is
1985 file based and takes file descriptors as system call argument
1986 for kernel and initramfs as opposed to list of segments as
1987 accepted by previous system call.
1988
1989config KEXEC_VERIFY_SIG
1990 bool "Verify kernel signature during kexec_file_load() syscall"
1991 depends on KEXEC_FILE
1992 ---help---
1993 This option makes kernel signature verification mandatory for
1994 the kexec_file_load() syscall.
1995
1996 In addition to that option, you need to enable signature
1997 verification for the corresponding kernel image type being
1998 loaded in order for this to work.
1999
2000config KEXEC_BZIMAGE_VERIFY_SIG
2001 bool "Enable bzImage signature verification support"
2002 depends on KEXEC_VERIFY_SIG
2003 depends on SIGNED_PE_FILE_VERIFICATION
2004 select SYSTEM_TRUSTED_KEYRING
2005 ---help---
2006 Enable bzImage signature verification support.
2007
2008config CRASH_DUMP
2009 bool "kernel crash dumps"
2010 depends on X86_64 || (X86_32 && HIGHMEM)
2011 ---help---
2012 Generate crash dump after being started by kexec.
2013 This should be normally only set in special crash dump kernels
2014 which are loaded in the main kernel with kexec-tools into
2015 a specially reserved region and then later executed after
2016 a crash by kdump/kexec. The crash dump kernel must be compiled
2017 to a memory address not used by the main kernel or BIOS using
2018 PHYSICAL_START, or it must be built as a relocatable image
2019 (CONFIG_RELOCATABLE=y).
2020 For more details see Documentation/kdump/kdump.txt
2021
2022config KEXEC_JUMP
2023 bool "kexec jump"
2024 depends on KEXEC && HIBERNATION
2025 ---help---
2026 Jump between original kernel and kexeced kernel and invoke
2027 code in physical address mode via KEXEC
2028
2029config PHYSICAL_START
2030 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2031 default "0x1000000"
2032 ---help---
2033 This gives the physical address where the kernel is loaded.
2034
2035 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2036 bzImage will decompress itself to above physical address and
2037 run from there. Otherwise, bzImage will run from the address where
2038 it has been loaded by the boot loader and will ignore above physical
2039 address.
2040
2041 In normal kdump cases one does not have to set/change this option
2042 as now bzImage can be compiled as a completely relocatable image
2043 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2044 address. This option is mainly useful for the folks who don't want
2045 to use a bzImage for capturing the crash dump and want to use a
2046 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2047 to be specifically compiled to run from a specific memory area
2048 (normally a reserved region) and this option comes handy.
2049
2050 So if you are using bzImage for capturing the crash dump,
2051 leave the value here unchanged to 0x1000000 and set
2052 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2053 for capturing the crash dump change this value to start of
2054 the reserved region. In other words, it can be set based on
2055 the "X" value as specified in the "crashkernel=YM@XM"
2056 command line boot parameter passed to the panic-ed
2057 kernel. Please take a look at Documentation/kdump/kdump.txt
2058 for more details about crash dumps.
2059
2060 Usage of bzImage for capturing the crash dump is recommended as
2061 one does not have to build two kernels. Same kernel can be used
2062 as production kernel and capture kernel. Above option should have
2063 gone away after relocatable bzImage support is introduced. But it
2064 is present because there are users out there who continue to use
2065 vmlinux for dump capture. This option should go away down the
2066 line.
2067
2068 Don't change this unless you know what you are doing.
2069
2070config RELOCATABLE
2071 bool "Build a relocatable kernel"
2072 default y
2073 ---help---
2074 This builds a kernel image that retains relocation information
2075 so it can be loaded someplace besides the default 1MB.
2076 The relocations tend to make the kernel binary about 10% larger,
2077 but are discarded at runtime.
2078
2079 One use is for the kexec on panic case where the recovery kernel
2080 must live at a different physical address than the primary
2081 kernel.
2082
2083 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2084 it has been loaded at and the compile time physical address
2085 (CONFIG_PHYSICAL_START) is used as the minimum location.
2086
2087config RANDOMIZE_BASE
2088 bool "Randomize the address of the kernel image (KASLR)"
2089 depends on RELOCATABLE
2090 default y
2091 ---help---
2092 In support of Kernel Address Space Layout Randomization (KASLR),
2093 this randomizes the physical address at which the kernel image
2094 is decompressed and the virtual address where the kernel
2095 image is mapped, as a security feature that deters exploit
2096 attempts relying on knowledge of the location of kernel
2097 code internals.
2098
2099 On 64-bit, the kernel physical and virtual addresses are
2100 randomized separately. The physical address will be anywhere
2101 between 16MB and the top of physical memory (up to 64TB). The
2102 virtual address will be randomized from 16MB up to 1GB (9 bits
2103 of entropy). Note that this also reduces the memory space
2104 available to kernel modules from 1.5GB to 1GB.
2105
2106 On 32-bit, the kernel physical and virtual addresses are
2107 randomized together. They will be randomized from 16MB up to
2108 512MB (8 bits of entropy).
2109
2110 Entropy is generated using the RDRAND instruction if it is
2111 supported. If RDTSC is supported, its value is mixed into
2112 the entropy pool as well. If neither RDRAND nor RDTSC are
2113 supported, then entropy is read from the i8254 timer. The
2114 usable entropy is limited by the kernel being built using
2115 2GB addressing, and that PHYSICAL_ALIGN must be at a
2116 minimum of 2MB. As a result, only 10 bits of entropy are
2117 theoretically possible, but the implementations are further
2118 limited due to memory layouts.
2119
2120 If unsure, say Y.
2121
2122# Relocation on x86 needs some additional build support
2123config X86_NEED_RELOCS
2124 def_bool y
2125 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2126
2127config PHYSICAL_ALIGN
2128 hex "Alignment value to which kernel should be aligned"
2129 default "0x200000"
2130 range 0x2000 0x1000000 if X86_32
2131 range 0x200000 0x1000000 if X86_64
2132 ---help---
2133 This value puts the alignment restrictions on physical address
2134 where kernel is loaded and run from. Kernel is compiled for an
2135 address which meets above alignment restriction.
2136
2137 If bootloader loads the kernel at a non-aligned address and
2138 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2139 address aligned to above value and run from there.
2140
2141 If bootloader loads the kernel at a non-aligned address and
2142 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2143 load address and decompress itself to the address it has been
2144 compiled for and run from there. The address for which kernel is
2145 compiled already meets above alignment restrictions. Hence the
2146 end result is that kernel runs from a physical address meeting
2147 above alignment restrictions.
2148
2149 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2150 this value must be a multiple of 0x200000.
2151
2152 Don't change this unless you know what you are doing.
2153
2154config RANDOMIZE_MEMORY
2155 bool "Randomize the kernel memory sections"
2156 depends on X86_64
2157 depends on RANDOMIZE_BASE
2158 default RANDOMIZE_BASE
2159 ---help---
2160 Randomizes the base virtual address of kernel memory sections
2161 (physical memory mapping, vmalloc & vmemmap). This security feature
2162 makes exploits relying on predictable memory locations less reliable.
2163
2164 The order of allocations remains unchanged. Entropy is generated in
2165 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2166 configuration have in average 30,000 different possible virtual
2167 addresses for each memory section.
2168
2169 If unsure, say Y.
2170
2171config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2172 hex "Physical memory mapping padding" if EXPERT
2173 depends on RANDOMIZE_MEMORY
2174 default "0xa" if MEMORY_HOTPLUG
2175 default "0x0"
2176 range 0x1 0x40 if MEMORY_HOTPLUG
2177 range 0x0 0x40
2178 ---help---
2179 Define the padding in terabytes added to the existing physical
2180 memory size during kernel memory randomization. It is useful
2181 for memory hotplug support but reduces the entropy available for
2182 address randomization.
2183
2184 If unsure, leave at the default value.
2185
2186config HOTPLUG_CPU
2187 def_bool y
2188 depends on SMP
2189
2190config BOOTPARAM_HOTPLUG_CPU0
2191 bool "Set default setting of cpu0_hotpluggable"
2192 default n
2193 depends on HOTPLUG_CPU
2194 ---help---
2195 Set whether default state of cpu0_hotpluggable is on or off.
2196
2197 Say Y here to enable CPU0 hotplug by default. If this switch
2198 is turned on, there is no need to give cpu0_hotplug kernel
2199 parameter and the CPU0 hotplug feature is enabled by default.
2200
2201 Please note: there are two known CPU0 dependencies if you want
2202 to enable the CPU0 hotplug feature either by this switch or by
2203 cpu0_hotplug kernel parameter.
2204
2205 First, resume from hibernate or suspend always starts from CPU0.
2206 So hibernate and suspend are prevented if CPU0 is offline.
2207
2208 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2209 offline if any interrupt can not migrate out of CPU0. There may
2210 be other CPU0 dependencies.
2211
2212 Please make sure the dependencies are under your control before
2213 you enable this feature.
2214
2215 Say N if you don't want to enable CPU0 hotplug feature by default.
2216 You still can enable the CPU0 hotplug feature at boot by kernel
2217 parameter cpu0_hotplug.
2218
2219config DEBUG_HOTPLUG_CPU0
2220 def_bool n
2221 prompt "Debug CPU0 hotplug"
2222 depends on HOTPLUG_CPU
2223 ---help---
2224 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2225 soon as possible and boots up userspace with CPU0 offlined. User
2226 can online CPU0 back after boot time.
2227
2228 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2229 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2230 compilation or giving cpu0_hotplug kernel parameter at boot.
2231
2232 If unsure, say N.
2233
2234config COMPAT_VDSO
2235 def_bool n
2236 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2237 depends on COMPAT_32
2238 ---help---
2239 Certain buggy versions of glibc will crash if they are
2240 presented with a 32-bit vDSO that is not mapped at the address
2241 indicated in its segment table.
2242
2243 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2244 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2245 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2246 the only released version with the bug, but OpenSUSE 9
2247 contains a buggy "glibc 2.3.2".
2248
2249 The symptom of the bug is that everything crashes on startup, saying:
2250 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2251
2252 Saying Y here changes the default value of the vdso32 boot
2253 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2254 This works around the glibc bug but hurts performance.
2255
2256 If unsure, say N: if you are compiling your own kernel, you
2257 are unlikely to be using a buggy version of glibc.
2258
2259choice
2260 prompt "vsyscall table for legacy applications"
2261 depends on X86_64
2262 default LEGACY_VSYSCALL_EMULATE
2263 help
2264 Legacy user code that does not know how to find the vDSO expects
2265 to be able to issue three syscalls by calling fixed addresses in
2266 kernel space. Since this location is not randomized with ASLR,
2267 it can be used to assist security vulnerability exploitation.
2268
2269 This setting can be changed at boot time via the kernel command
2270 line parameter vsyscall=[native|emulate|none].
2271
2272 On a system with recent enough glibc (2.14 or newer) and no
2273 static binaries, you can say None without a performance penalty
2274 to improve security.
2275
2276 If unsure, select "Emulate".
2277
2278 config LEGACY_VSYSCALL_NATIVE
2279 bool "Native"
2280 help
2281 Actual executable code is located in the fixed vsyscall
2282 address mapping, implementing time() efficiently. Since
2283 this makes the mapping executable, it can be used during
2284 security vulnerability exploitation (traditionally as
2285 ROP gadgets). This configuration is not recommended.
2286
2287 config LEGACY_VSYSCALL_EMULATE
2288 bool "Emulate"
2289 help
2290 The kernel traps and emulates calls into the fixed
2291 vsyscall address mapping. This makes the mapping
2292 non-executable, but it still contains known contents,
2293 which could be used in certain rare security vulnerability
2294 exploits. This configuration is recommended when userspace
2295 still uses the vsyscall area.
2296
2297 config LEGACY_VSYSCALL_NONE
2298 bool "None"
2299 help
2300 There will be no vsyscall mapping at all. This will
2301 eliminate any risk of ASLR bypass due to the vsyscall
2302 fixed address mapping. Attempts to use the vsyscalls
2303 will be reported to dmesg, so that either old or
2304 malicious userspace programs can be identified.
2305
2306endchoice
2307
2308config CMDLINE_BOOL
2309 bool "Built-in kernel command line"
2310 ---help---
2311 Allow for specifying boot arguments to the kernel at
2312 build time. On some systems (e.g. embedded ones), it is
2313 necessary or convenient to provide some or all of the
2314 kernel boot arguments with the kernel itself (that is,
2315 to not rely on the boot loader to provide them.)
2316
2317 To compile command line arguments into the kernel,
2318 set this option to 'Y', then fill in the
2319 boot arguments in CONFIG_CMDLINE.
2320
2321 Systems with fully functional boot loaders (i.e. non-embedded)
2322 should leave this option set to 'N'.
2323
2324config CMDLINE
2325 string "Built-in kernel command string"
2326 depends on CMDLINE_BOOL
2327 default ""
2328 ---help---
2329 Enter arguments here that should be compiled into the kernel
2330 image and used at boot time. If the boot loader provides a
2331 command line at boot time, it is appended to this string to
2332 form the full kernel command line, when the system boots.
2333
2334 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2335 change this behavior.
2336
2337 In most cases, the command line (whether built-in or provided
2338 by the boot loader) should specify the device for the root
2339 file system.
2340
2341config CMDLINE_OVERRIDE
2342 bool "Built-in command line overrides boot loader arguments"
2343 depends on CMDLINE_BOOL
2344 ---help---
2345 Set this option to 'Y' to have the kernel ignore the boot loader
2346 command line, and use ONLY the built-in command line.
2347
2348 This is used to work around broken boot loaders. This should
2349 be set to 'N' under normal conditions.
2350
2351config MODIFY_LDT_SYSCALL
2352 bool "Enable the LDT (local descriptor table)" if EXPERT
2353 default y
2354 ---help---
2355 Linux can allow user programs to install a per-process x86
2356 Local Descriptor Table (LDT) using the modify_ldt(2) system
2357 call. This is required to run 16-bit or segmented code such as
2358 DOSEMU or some Wine programs. It is also used by some very old
2359 threading libraries.
2360
2361 Enabling this feature adds a small amount of overhead to
2362 context switches and increases the low-level kernel attack
2363 surface. Disabling it removes the modify_ldt(2) system call.
2364
2365 Saying 'N' here may make sense for embedded or server kernels.
2366
2367source "kernel/livepatch/Kconfig"
2368
2369endmenu
2370
2371config ARCH_HAS_ADD_PAGES
2372 def_bool y
2373 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2374
2375config ARCH_ENABLE_MEMORY_HOTPLUG
2376 def_bool y
2377 depends on X86_64 || (X86_32 && HIGHMEM)
2378
2379config ARCH_ENABLE_MEMORY_HOTREMOVE
2380 def_bool y
2381 depends on MEMORY_HOTPLUG
2382
2383config USE_PERCPU_NUMA_NODE_ID
2384 def_bool y
2385 depends on NUMA
2386
2387config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2388 def_bool y
2389 depends on X86_64 || X86_PAE
2390
2391config ARCH_ENABLE_HUGEPAGE_MIGRATION
2392 def_bool y
2393 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2394
2395config ARCH_ENABLE_THP_MIGRATION
2396 def_bool y
2397 depends on X86_64 && TRANSPARENT_HUGEPAGE
2398
2399menu "Power management and ACPI options"
2400
2401config ARCH_HIBERNATION_HEADER
2402 def_bool y
2403 depends on X86_64 && HIBERNATION
2404
2405source "kernel/power/Kconfig"
2406
2407source "drivers/acpi/Kconfig"
2408
2409source "drivers/sfi/Kconfig"
2410
2411config X86_APM_BOOT
2412 def_bool y
2413 depends on APM
2414
2415menuconfig APM
2416 tristate "APM (Advanced Power Management) BIOS support"
2417 depends on X86_32 && PM_SLEEP
2418 ---help---
2419 APM is a BIOS specification for saving power using several different
2420 techniques. This is mostly useful for battery powered laptops with
2421 APM compliant BIOSes. If you say Y here, the system time will be
2422 reset after a RESUME operation, the /proc/apm device will provide
2423 battery status information, and user-space programs will receive
2424 notification of APM "events" (e.g. battery status change).
2425
2426 If you select "Y" here, you can disable actual use of the APM
2427 BIOS by passing the "apm=off" option to the kernel at boot time.
2428
2429 Note that the APM support is almost completely disabled for
2430 machines with more than one CPU.
2431
2432 In order to use APM, you will need supporting software. For location
2433 and more information, read <file:Documentation/power/apm-acpi.txt>
2434 and the Battery Powered Linux mini-HOWTO, available from
2435 <http://www.tldp.org/docs.html#howto>.
2436
2437 This driver does not spin down disk drives (see the hdparm(8)
2438 manpage ("man 8 hdparm") for that), and it doesn't turn off
2439 VESA-compliant "green" monitors.
2440
2441 This driver does not support the TI 4000M TravelMate and the ACER
2442 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2443 desktop machines also don't have compliant BIOSes, and this driver
2444 may cause those machines to panic during the boot phase.
2445
2446 Generally, if you don't have a battery in your machine, there isn't
2447 much point in using this driver and you should say N. If you get
2448 random kernel OOPSes or reboots that don't seem to be related to
2449 anything, try disabling/enabling this option (or disabling/enabling
2450 APM in your BIOS).
2451
2452 Some other things you should try when experiencing seemingly random,
2453 "weird" problems:
2454
2455 1) make sure that you have enough swap space and that it is
2456 enabled.
2457 2) pass the "no-hlt" option to the kernel
2458 3) switch on floating point emulation in the kernel and pass
2459 the "no387" option to the kernel
2460 4) pass the "floppy=nodma" option to the kernel
2461 5) pass the "mem=4M" option to the kernel (thereby disabling
2462 all but the first 4 MB of RAM)
2463 6) make sure that the CPU is not over clocked.
2464 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2465 8) disable the cache from your BIOS settings
2466 9) install a fan for the video card or exchange video RAM
2467 10) install a better fan for the CPU
2468 11) exchange RAM chips
2469 12) exchange the motherboard.
2470
2471 To compile this driver as a module, choose M here: the
2472 module will be called apm.
2473
2474if APM
2475
2476config APM_IGNORE_USER_SUSPEND
2477 bool "Ignore USER SUSPEND"
2478 ---help---
2479 This option will ignore USER SUSPEND requests. On machines with a
2480 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2481 series notebooks, it is necessary to say Y because of a BIOS bug.
2482
2483config APM_DO_ENABLE
2484 bool "Enable PM at boot time"
2485 ---help---
2486 Enable APM features at boot time. From page 36 of the APM BIOS
2487 specification: "When disabled, the APM BIOS does not automatically
2488 power manage devices, enter the Standby State, enter the Suspend
2489 State, or take power saving steps in response to CPU Idle calls."
2490 This driver will make CPU Idle calls when Linux is idle (unless this
2491 feature is turned off -- see "Do CPU IDLE calls", below). This
2492 should always save battery power, but more complicated APM features
2493 will be dependent on your BIOS implementation. You may need to turn
2494 this option off if your computer hangs at boot time when using APM
2495 support, or if it beeps continuously instead of suspending. Turn
2496 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2497 T400CDT. This is off by default since most machines do fine without
2498 this feature.
2499
2500config APM_CPU_IDLE
2501 depends on CPU_IDLE
2502 bool "Make CPU Idle calls when idle"
2503 ---help---
2504 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2505 On some machines, this can activate improved power savings, such as
2506 a slowed CPU clock rate, when the machine is idle. These idle calls
2507 are made after the idle loop has run for some length of time (e.g.,
2508 333 mS). On some machines, this will cause a hang at boot time or
2509 whenever the CPU becomes idle. (On machines with more than one CPU,
2510 this option does nothing.)
2511
2512config APM_DISPLAY_BLANK
2513 bool "Enable console blanking using APM"
2514 ---help---
2515 Enable console blanking using the APM. Some laptops can use this to
2516 turn off the LCD backlight when the screen blanker of the Linux
2517 virtual console blanks the screen. Note that this is only used by
2518 the virtual console screen blanker, and won't turn off the backlight
2519 when using the X Window system. This also doesn't have anything to
2520 do with your VESA-compliant power-saving monitor. Further, this
2521 option doesn't work for all laptops -- it might not turn off your
2522 backlight at all, or it might print a lot of errors to the console,
2523 especially if you are using gpm.
2524
2525config APM_ALLOW_INTS
2526 bool "Allow interrupts during APM BIOS calls"
2527 ---help---
2528 Normally we disable external interrupts while we are making calls to
2529 the APM BIOS as a measure to lessen the effects of a badly behaving
2530 BIOS implementation. The BIOS should reenable interrupts if it
2531 needs to. Unfortunately, some BIOSes do not -- especially those in
2532 many of the newer IBM Thinkpads. If you experience hangs when you
2533 suspend, try setting this to Y. Otherwise, say N.
2534
2535endif # APM
2536
2537source "drivers/cpufreq/Kconfig"
2538
2539source "drivers/cpuidle/Kconfig"
2540
2541source "drivers/idle/Kconfig"
2542
2543endmenu
2544
2545
2546menu "Bus options (PCI etc.)"
2547
2548config PCI
2549 bool "PCI support"
2550 default y
2551 ---help---
2552 Find out whether you have a PCI motherboard. PCI is the name of a
2553 bus system, i.e. the way the CPU talks to the other stuff inside
2554 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2555 VESA. If you have PCI, say Y, otherwise N.
2556
2557choice
2558 prompt "PCI access mode"
2559 depends on X86_32 && PCI
2560 default PCI_GOANY
2561 ---help---
2562 On PCI systems, the BIOS can be used to detect the PCI devices and
2563 determine their configuration. However, some old PCI motherboards
2564 have BIOS bugs and may crash if this is done. Also, some embedded
2565 PCI-based systems don't have any BIOS at all. Linux can also try to
2566 detect the PCI hardware directly without using the BIOS.
2567
2568 With this option, you can specify how Linux should detect the
2569 PCI devices. If you choose "BIOS", the BIOS will be used,
2570 if you choose "Direct", the BIOS won't be used, and if you
2571 choose "MMConfig", then PCI Express MMCONFIG will be used.
2572 If you choose "Any", the kernel will try MMCONFIG, then the
2573 direct access method and falls back to the BIOS if that doesn't
2574 work. If unsure, go with the default, which is "Any".
2575
2576config PCI_GOBIOS
2577 bool "BIOS"
2578
2579config PCI_GOMMCONFIG
2580 bool "MMConfig"
2581
2582config PCI_GODIRECT
2583 bool "Direct"
2584
2585config PCI_GOOLPC
2586 bool "OLPC XO-1"
2587 depends on OLPC
2588
2589config PCI_GOANY
2590 bool "Any"
2591
2592endchoice
2593
2594config PCI_BIOS
2595 def_bool y
2596 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2597
2598# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2599config PCI_DIRECT
2600 def_bool y
2601 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2602
2603config PCI_MMCONFIG
2604 def_bool y
2605 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2606
2607config PCI_OLPC
2608 def_bool y
2609 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2610
2611config PCI_XEN
2612 def_bool y
2613 depends on PCI && XEN
2614 select SWIOTLB_XEN
2615
2616config PCI_DOMAINS
2617 def_bool y
2618 depends on PCI
2619
2620config PCI_MMCONFIG
2621 bool "Support mmconfig PCI config space access"
2622 depends on X86_64 && PCI && ACPI
2623
2624config PCI_CNB20LE_QUIRK
2625 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2626 depends on PCI
2627 help
2628 Read the PCI windows out of the CNB20LE host bridge. This allows
2629 PCI hotplug to work on systems with the CNB20LE chipset which do
2630 not have ACPI.
2631
2632 There's no public spec for this chipset, and this functionality
2633 is known to be incomplete.
2634
2635 You should say N unless you know you need this.
2636
2637source "drivers/pci/Kconfig"
2638
2639config ISA_BUS
2640 bool "ISA-style bus support on modern systems" if EXPERT
2641 select ISA_BUS_API
2642 help
2643 Enables ISA-style drivers on modern systems. This is necessary to
2644 support PC/104 devices on X86_64 platforms.
2645
2646 If unsure, say N.
2647
2648# x86_64 have no ISA slots, but can have ISA-style DMA.
2649config ISA_DMA_API
2650 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2651 default y
2652 help
2653 Enables ISA-style DMA support for devices requiring such controllers.
2654 If unsure, say Y.
2655
2656if X86_32
2657
2658config ISA
2659 bool "ISA support"
2660 ---help---
2661 Find out whether you have ISA slots on your motherboard. ISA is the
2662 name of a bus system, i.e. the way the CPU talks to the other stuff
2663 inside your box. Other bus systems are PCI, EISA, MicroChannel
2664 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2665 newer boards don't support it. If you have ISA, say Y, otherwise N.
2666
2667config EISA
2668 bool "EISA support"
2669 depends on ISA
2670 ---help---
2671 The Extended Industry Standard Architecture (EISA) bus was
2672 developed as an open alternative to the IBM MicroChannel bus.
2673
2674 The EISA bus provided some of the features of the IBM MicroChannel
2675 bus while maintaining backward compatibility with cards made for
2676 the older ISA bus. The EISA bus saw limited use between 1988 and
2677 1995 when it was made obsolete by the PCI bus.
2678
2679 Say Y here if you are building a kernel for an EISA-based machine.
2680
2681 Otherwise, say N.
2682
2683source "drivers/eisa/Kconfig"
2684
2685config SCx200
2686 tristate "NatSemi SCx200 support"
2687 ---help---
2688 This provides basic support for National Semiconductor's
2689 (now AMD's) Geode processors. The driver probes for the
2690 PCI-IDs of several on-chip devices, so its a good dependency
2691 for other scx200_* drivers.
2692
2693 If compiled as a module, the driver is named scx200.
2694
2695config SCx200HR_TIMER
2696 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2697 depends on SCx200
2698 default y
2699 ---help---
2700 This driver provides a clocksource built upon the on-chip
2701 27MHz high-resolution timer. Its also a workaround for
2702 NSC Geode SC-1100's buggy TSC, which loses time when the
2703 processor goes idle (as is done by the scheduler). The
2704 other workaround is idle=poll boot option.
2705
2706config OLPC
2707 bool "One Laptop Per Child support"
2708 depends on !X86_PAE
2709 select GPIOLIB
2710 select OF
2711 select OF_PROMTREE
2712 select IRQ_DOMAIN
2713 ---help---
2714 Add support for detecting the unique features of the OLPC
2715 XO hardware.
2716
2717config OLPC_XO1_PM
2718 bool "OLPC XO-1 Power Management"
2719 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2720 ---help---
2721 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2722
2723config OLPC_XO1_RTC
2724 bool "OLPC XO-1 Real Time Clock"
2725 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2726 ---help---
2727 Add support for the XO-1 real time clock, which can be used as a
2728 programmable wakeup source.
2729
2730config OLPC_XO1_SCI
2731 bool "OLPC XO-1 SCI extras"
2732 depends on OLPC && OLPC_XO1_PM
2733 depends on INPUT=y
2734 select POWER_SUPPLY
2735 select GPIO_CS5535
2736 select MFD_CORE
2737 ---help---
2738 Add support for SCI-based features of the OLPC XO-1 laptop:
2739 - EC-driven system wakeups
2740 - Power button
2741 - Ebook switch
2742 - Lid switch
2743 - AC adapter status updates
2744 - Battery status updates
2745
2746config OLPC_XO15_SCI
2747 bool "OLPC XO-1.5 SCI extras"
2748 depends on OLPC && ACPI
2749 select POWER_SUPPLY
2750 ---help---
2751 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2752 - EC-driven system wakeups
2753 - AC adapter status updates
2754 - Battery status updates
2755
2756config ALIX
2757 bool "PCEngines ALIX System Support (LED setup)"
2758 select GPIOLIB
2759 ---help---
2760 This option enables system support for the PCEngines ALIX.
2761 At present this just sets up LEDs for GPIO control on
2762 ALIX2/3/6 boards. However, other system specific setup should
2763 get added here.
2764
2765 Note: You must still enable the drivers for GPIO and LED support
2766 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2767
2768 Note: You have to set alix.force=1 for boards with Award BIOS.
2769
2770config NET5501
2771 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2772 select GPIOLIB
2773 ---help---
2774 This option enables system support for the Soekris Engineering net5501.
2775
2776config GEOS
2777 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2778 select GPIOLIB
2779 depends on DMI
2780 ---help---
2781 This option enables system support for the Traverse Technologies GEOS.
2782
2783config TS5500
2784 bool "Technologic Systems TS-5500 platform support"
2785 depends on MELAN
2786 select CHECK_SIGNATURE
2787 select NEW_LEDS
2788 select LEDS_CLASS
2789 ---help---
2790 This option enables system support for the Technologic Systems TS-5500.
2791
2792endif # X86_32
2793
2794config AMD_NB
2795 def_bool y
2796 depends on CPU_SUP_AMD && PCI
2797
2798source "drivers/pcmcia/Kconfig"
2799
2800config RAPIDIO
2801 tristate "RapidIO support"
2802 depends on PCI
2803 default n
2804 help
2805 If enabled this option will include drivers and the core
2806 infrastructure code to support RapidIO interconnect devices.
2807
2808source "drivers/rapidio/Kconfig"
2809
2810config X86_SYSFB
2811 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2812 help
2813 Firmwares often provide initial graphics framebuffers so the BIOS,
2814 bootloader or kernel can show basic video-output during boot for
2815 user-guidance and debugging. Historically, x86 used the VESA BIOS
2816 Extensions and EFI-framebuffers for this, which are mostly limited
2817 to x86.
2818 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2819 framebuffers so the new generic system-framebuffer drivers can be
2820 used on x86. If the framebuffer is not compatible with the generic
2821 modes, it is adverticed as fallback platform framebuffer so legacy
2822 drivers like efifb, vesafb and uvesafb can pick it up.
2823 If this option is not selected, all system framebuffers are always
2824 marked as fallback platform framebuffers as usual.
2825
2826 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2827 not be able to pick up generic system framebuffers if this option
2828 is selected. You are highly encouraged to enable simplefb as
2829 replacement if you select this option. simplefb can correctly deal
2830 with generic system framebuffers. But you should still keep vesafb
2831 and others enabled as fallback if a system framebuffer is
2832 incompatible with simplefb.
2833
2834 If unsure, say Y.
2835
2836endmenu
2837
2838
2839menu "Executable file formats / Emulations"
2840
2841source "fs/Kconfig.binfmt"
2842
2843config IA32_EMULATION
2844 bool "IA32 Emulation"
2845 depends on X86_64
2846 select ARCH_WANT_OLD_COMPAT_IPC
2847 select BINFMT_ELF
2848 select COMPAT_BINFMT_ELF
2849 select COMPAT_OLD_SIGACTION
2850 ---help---
2851 Include code to run legacy 32-bit programs under a
2852 64-bit kernel. You should likely turn this on, unless you're
2853 100% sure that you don't have any 32-bit programs left.
2854
2855config IA32_AOUT
2856 tristate "IA32 a.out support"
2857 depends on IA32_EMULATION
2858 ---help---
2859 Support old a.out binaries in the 32bit emulation.
2860
2861config X86_X32
2862 bool "x32 ABI for 64-bit mode"
2863 depends on X86_64
2864 ---help---
2865 Include code to run binaries for the x32 native 32-bit ABI
2866 for 64-bit processors. An x32 process gets access to the
2867 full 64-bit register file and wide data path while leaving
2868 pointers at 32 bits for smaller memory footprint.
2869
2870 You will need a recent binutils (2.22 or later) with
2871 elf32_x86_64 support enabled to compile a kernel with this
2872 option set.
2873
2874config COMPAT_32
2875 def_bool y
2876 depends on IA32_EMULATION || X86_32
2877 select HAVE_UID16
2878 select OLD_SIGSUSPEND3
2879
2880config COMPAT
2881 def_bool y
2882 depends on IA32_EMULATION || X86_X32
2883
2884if COMPAT
2885config COMPAT_FOR_U64_ALIGNMENT
2886 def_bool y
2887
2888config SYSVIPC_COMPAT
2889 def_bool y
2890 depends on SYSVIPC
2891endif
2892
2893endmenu
2894
2895
2896config HAVE_ATOMIC_IOMAP
2897 def_bool y
2898 depends on X86_32
2899
2900config X86_DEV_DMA_OPS
2901 bool
2902 depends on X86_64 || STA2X11
2903
2904config X86_DMA_REMAP
2905 bool
2906 depends on STA2X11
2907
2908config HAVE_GENERIC_GUP
2909 def_bool y
2910
2911source "net/Kconfig"
2912
2913source "drivers/Kconfig"
2914
2915source "drivers/firmware/Kconfig"
2916
2917source "fs/Kconfig"
2918
2919source "arch/x86/Kconfig.debug"
2920
2921source "security/Kconfig"
2922
2923source "crypto/Kconfig"
2924
2925source "arch/x86/kvm/Kconfig"
2926
2927source "lib/Kconfig"