Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1# 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 select ARCH_HAS_SYSCALL_WRAPPER
33
34#
35# Arch settings
36#
37# ( Note that options that are marked 'if X86_64' could in principle be
38# ported to 32-bit as well. )
39#
40config X86
41 def_bool y
42 #
43 # Note: keep this list sorted alphabetically
44 #
45 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
46 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
47 select ANON_INODES
48 select ARCH_CLOCKSOURCE_DATA
49 select ARCH_DISCARD_MEMBLOCK
50 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
51 select ARCH_HAS_DEBUG_VIRTUAL
52 select ARCH_HAS_DEVMEM_IS_ALLOWED
53 select ARCH_HAS_ELF_RANDOMIZE
54 select ARCH_HAS_FAST_MULTIPLIER
55 select ARCH_HAS_FILTER_PGPROT
56 select ARCH_HAS_FORTIFY_SOURCE
57 select ARCH_HAS_GCOV_PROFILE_ALL
58 select ARCH_HAS_KCOV if X86_64
59 select ARCH_HAS_MEMBARRIER_SYNC_CORE
60 select ARCH_HAS_PMEM_API if X86_64
61 select ARCH_HAS_REFCOUNT
62 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
63 select ARCH_HAS_SET_MEMORY
64 select ARCH_HAS_SG_CHAIN
65 select ARCH_HAS_STRICT_KERNEL_RWX
66 select ARCH_HAS_STRICT_MODULE_RWX
67 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
68 select ARCH_HAS_UBSAN_SANITIZE_ALL
69 select ARCH_HAS_ZONE_DEVICE if X86_64
70 select ARCH_HAVE_NMI_SAFE_CMPXCHG
71 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
72 select ARCH_MIGHT_HAVE_PC_PARPORT
73 select ARCH_MIGHT_HAVE_PC_SERIO
74 select ARCH_SUPPORTS_ATOMIC_RMW
75 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
76 select ARCH_USE_BUILTIN_BSWAP
77 select ARCH_USE_QUEUED_RWLOCKS
78 select ARCH_USE_QUEUED_SPINLOCKS
79 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
80 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
81 select ARCH_WANTS_THP_SWAP if X86_64
82 select BUILDTIME_EXTABLE_SORT
83 select CLKEVT_I8253
84 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
85 select CLOCKSOURCE_WATCHDOG
86 select DCACHE_WORD_ACCESS
87 select DMA_DIRECT_OPS
88 select EDAC_ATOMIC_SCRUB
89 select EDAC_SUPPORT
90 select GENERIC_CLOCKEVENTS
91 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
92 select GENERIC_CLOCKEVENTS_MIN_ADJUST
93 select GENERIC_CMOS_UPDATE
94 select GENERIC_CPU_AUTOPROBE
95 select GENERIC_CPU_VULNERABILITIES
96 select GENERIC_EARLY_IOREMAP
97 select GENERIC_FIND_FIRST_BIT
98 select GENERIC_IOMAP
99 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
100 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
101 select GENERIC_IRQ_MIGRATION if SMP
102 select GENERIC_IRQ_PROBE
103 select GENERIC_IRQ_RESERVATION_MODE
104 select GENERIC_IRQ_SHOW
105 select GENERIC_PENDING_IRQ if SMP
106 select GENERIC_SMP_IDLE_THREAD
107 select GENERIC_STRNCPY_FROM_USER
108 select GENERIC_STRNLEN_USER
109 select GENERIC_TIME_VSYSCALL
110 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
111 select HAVE_ACPI_APEI if ACPI
112 select HAVE_ACPI_APEI_NMI if ACPI
113 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
114 select HAVE_ARCH_AUDITSYSCALL
115 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
116 select HAVE_ARCH_JUMP_LABEL
117 select HAVE_ARCH_KASAN if X86_64
118 select HAVE_ARCH_KGDB
119 select HAVE_ARCH_MMAP_RND_BITS if MMU
120 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
121 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
122 select HAVE_ARCH_SECCOMP_FILTER
123 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
124 select HAVE_ARCH_TRACEHOOK
125 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
126 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
127 select HAVE_ARCH_VMAP_STACK if X86_64
128 select HAVE_ARCH_WITHIN_STACK_FRAMES
129 select HAVE_CC_STACKPROTECTOR
130 select HAVE_CMPXCHG_DOUBLE
131 select HAVE_CMPXCHG_LOCAL
132 select HAVE_CONTEXT_TRACKING if X86_64
133 select HAVE_COPY_THREAD_TLS
134 select HAVE_C_RECORDMCOUNT
135 select HAVE_DEBUG_KMEMLEAK
136 select HAVE_DEBUG_STACKOVERFLOW
137 select HAVE_DMA_API_DEBUG
138 select HAVE_DMA_CONTIGUOUS
139 select HAVE_DYNAMIC_FTRACE
140 select HAVE_DYNAMIC_FTRACE_WITH_REGS
141 select HAVE_EBPF_JIT if X86_64
142 select HAVE_EFFICIENT_UNALIGNED_ACCESS
143 select HAVE_EXIT_THREAD
144 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
145 select HAVE_FTRACE_MCOUNT_RECORD
146 select HAVE_FUNCTION_GRAPH_TRACER
147 select HAVE_FUNCTION_TRACER
148 select HAVE_GCC_PLUGINS
149 select HAVE_HW_BREAKPOINT
150 select HAVE_IDE
151 select HAVE_IOREMAP_PROT
152 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
153 select HAVE_IRQ_TIME_ACCOUNTING
154 select HAVE_KERNEL_BZIP2
155 select HAVE_KERNEL_GZIP
156 select HAVE_KERNEL_LZ4
157 select HAVE_KERNEL_LZMA
158 select HAVE_KERNEL_LZO
159 select HAVE_KERNEL_XZ
160 select HAVE_KPROBES
161 select HAVE_KPROBES_ON_FTRACE
162 select HAVE_FUNCTION_ERROR_INJECTION
163 select HAVE_KRETPROBES
164 select HAVE_KVM
165 select HAVE_LIVEPATCH if X86_64
166 select HAVE_MEMBLOCK
167 select HAVE_MEMBLOCK_NODE_MAP
168 select HAVE_MIXED_BREAKPOINTS_REGS
169 select HAVE_MOD_ARCH_SPECIFIC
170 select HAVE_NMI
171 select HAVE_OPROFILE
172 select HAVE_OPTPROBES
173 select HAVE_PCSPKR_PLATFORM
174 select HAVE_PERF_EVENTS
175 select HAVE_PERF_EVENTS_NMI
176 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
177 select HAVE_PERF_REGS
178 select HAVE_PERF_USER_STACK_DUMP
179 select HAVE_RCU_TABLE_FREE
180 select HAVE_REGS_AND_STACK_ACCESS_API
181 select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION
182 select HAVE_STACK_VALIDATION if X86_64
183 select HAVE_SYSCALL_TRACEPOINTS
184 select HAVE_UNSTABLE_SCHED_CLOCK
185 select HAVE_USER_RETURN_NOTIFIER
186 select IRQ_FORCED_THREADING
187 select PCI_LOCKLESS_CONFIG
188 select PERF_EVENTS
189 select RTC_LIB
190 select RTC_MC146818_LIB
191 select SPARSE_IRQ
192 select SRCU
193 select SYSCTL_EXCEPTION_TRACE
194 select THREAD_INFO_IN_TASK
195 select USER_STACKTRACE_SUPPORT
196 select VIRT_TO_BUS
197 select X86_FEATURE_NAMES if PROC_FS
198
199config INSTRUCTION_DECODER
200 def_bool y
201 depends on KPROBES || PERF_EVENTS || UPROBES
202
203config OUTPUT_FORMAT
204 string
205 default "elf32-i386" if X86_32
206 default "elf64-x86-64" if X86_64
207
208config ARCH_DEFCONFIG
209 string
210 default "arch/x86/configs/i386_defconfig" if X86_32
211 default "arch/x86/configs/x86_64_defconfig" if X86_64
212
213config LOCKDEP_SUPPORT
214 def_bool y
215
216config STACKTRACE_SUPPORT
217 def_bool y
218
219config MMU
220 def_bool y
221
222config ARCH_MMAP_RND_BITS_MIN
223 default 28 if 64BIT
224 default 8
225
226config ARCH_MMAP_RND_BITS_MAX
227 default 32 if 64BIT
228 default 16
229
230config ARCH_MMAP_RND_COMPAT_BITS_MIN
231 default 8
232
233config ARCH_MMAP_RND_COMPAT_BITS_MAX
234 default 16
235
236config SBUS
237 bool
238
239config NEED_DMA_MAP_STATE
240 def_bool y
241 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
242
243config NEED_SG_DMA_LENGTH
244 def_bool y
245
246config GENERIC_ISA_DMA
247 def_bool y
248 depends on ISA_DMA_API
249
250config GENERIC_BUG
251 def_bool y
252 depends on BUG
253 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
254
255config GENERIC_BUG_RELATIVE_POINTERS
256 bool
257
258config GENERIC_HWEIGHT
259 def_bool y
260
261config ARCH_MAY_HAVE_PC_FDC
262 def_bool y
263 depends on ISA_DMA_API
264
265config RWSEM_XCHGADD_ALGORITHM
266 def_bool y
267
268config GENERIC_CALIBRATE_DELAY
269 def_bool y
270
271config ARCH_HAS_CPU_RELAX
272 def_bool y
273
274config ARCH_HAS_CACHE_LINE_SIZE
275 def_bool y
276
277config ARCH_HAS_FILTER_PGPROT
278 def_bool y
279
280config HAVE_SETUP_PER_CPU_AREA
281 def_bool y
282
283config NEED_PER_CPU_EMBED_FIRST_CHUNK
284 def_bool y
285
286config NEED_PER_CPU_PAGE_FIRST_CHUNK
287 def_bool y
288
289config ARCH_HIBERNATION_POSSIBLE
290 def_bool y
291
292config ARCH_SUSPEND_POSSIBLE
293 def_bool y
294
295config ARCH_WANT_HUGE_PMD_SHARE
296 def_bool y
297
298config ARCH_WANT_GENERAL_HUGETLB
299 def_bool y
300
301config ZONE_DMA32
302 def_bool y if X86_64
303
304config AUDIT_ARCH
305 def_bool y if X86_64
306
307config ARCH_SUPPORTS_OPTIMIZED_INLINING
308 def_bool y
309
310config ARCH_SUPPORTS_DEBUG_PAGEALLOC
311 def_bool y
312
313config KASAN_SHADOW_OFFSET
314 hex
315 depends on KASAN
316 default 0xdffffc0000000000
317
318config HAVE_INTEL_TXT
319 def_bool y
320 depends on INTEL_IOMMU && ACPI
321
322config X86_32_SMP
323 def_bool y
324 depends on X86_32 && SMP
325
326config X86_64_SMP
327 def_bool y
328 depends on X86_64 && SMP
329
330config X86_32_LAZY_GS
331 def_bool y
332 depends on X86_32 && CC_STACKPROTECTOR_NONE
333
334config ARCH_SUPPORTS_UPROBES
335 def_bool y
336
337config FIX_EARLYCON_MEM
338 def_bool y
339
340config PGTABLE_LEVELS
341 int
342 default 5 if X86_5LEVEL
343 default 4 if X86_64
344 default 3 if X86_PAE
345 default 2
346
347source "init/Kconfig"
348source "kernel/Kconfig.freezer"
349
350menu "Processor type and features"
351
352config ZONE_DMA
353 bool "DMA memory allocation support" if EXPERT
354 default y
355 help
356 DMA memory allocation support allows devices with less than 32-bit
357 addressing to allocate within the first 16MB of address space.
358 Disable if no such devices will be used.
359
360 If unsure, say Y.
361
362config SMP
363 bool "Symmetric multi-processing support"
364 ---help---
365 This enables support for systems with more than one CPU. If you have
366 a system with only one CPU, say N. If you have a system with more
367 than one CPU, say Y.
368
369 If you say N here, the kernel will run on uni- and multiprocessor
370 machines, but will use only one CPU of a multiprocessor machine. If
371 you say Y here, the kernel will run on many, but not all,
372 uniprocessor machines. On a uniprocessor machine, the kernel
373 will run faster if you say N here.
374
375 Note that if you say Y here and choose architecture "586" or
376 "Pentium" under "Processor family", the kernel will not work on 486
377 architectures. Similarly, multiprocessor kernels for the "PPro"
378 architecture may not work on all Pentium based boards.
379
380 People using multiprocessor machines who say Y here should also say
381 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
382 Management" code will be disabled if you say Y here.
383
384 See also <file:Documentation/x86/i386/IO-APIC.txt>,
385 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
386 <http://www.tldp.org/docs.html#howto>.
387
388 If you don't know what to do here, say N.
389
390config X86_FEATURE_NAMES
391 bool "Processor feature human-readable names" if EMBEDDED
392 default y
393 ---help---
394 This option compiles in a table of x86 feature bits and corresponding
395 names. This is required to support /proc/cpuinfo and a few kernel
396 messages. You can disable this to save space, at the expense of
397 making those few kernel messages show numeric feature bits instead.
398
399 If in doubt, say Y.
400
401config X86_X2APIC
402 bool "Support x2apic"
403 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
404 ---help---
405 This enables x2apic support on CPUs that have this feature.
406
407 This allows 32-bit apic IDs (so it can support very large systems),
408 and accesses the local apic via MSRs not via mmio.
409
410 If you don't know what to do here, say N.
411
412config X86_MPPARSE
413 bool "Enable MPS table" if ACPI || SFI
414 default y
415 depends on X86_LOCAL_APIC
416 ---help---
417 For old smp systems that do not have proper acpi support. Newer systems
418 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
419
420config GOLDFISH
421 def_bool y
422 depends on X86_GOLDFISH
423
424config RETPOLINE
425 bool "Avoid speculative indirect branches in kernel"
426 default y
427 select STACK_VALIDATION if HAVE_STACK_VALIDATION
428 help
429 Compile kernel with the retpoline compiler options to guard against
430 kernel-to-user data leaks by avoiding speculative indirect
431 branches. Requires a compiler with -mindirect-branch=thunk-extern
432 support for full protection. The kernel may run slower.
433
434 Without compiler support, at least indirect branches in assembler
435 code are eliminated. Since this includes the syscall entry path,
436 it is not entirely pointless.
437
438config INTEL_RDT
439 bool "Intel Resource Director Technology support"
440 default n
441 depends on X86 && CPU_SUP_INTEL
442 select KERNFS
443 help
444 Select to enable resource allocation and monitoring which are
445 sub-features of Intel Resource Director Technology(RDT). More
446 information about RDT can be found in the Intel x86
447 Architecture Software Developer Manual.
448
449 Say N if unsure.
450
451if X86_32
452config X86_BIGSMP
453 bool "Support for big SMP systems with more than 8 CPUs"
454 depends on SMP
455 ---help---
456 This option is needed for the systems that have more than 8 CPUs
457
458config X86_EXTENDED_PLATFORM
459 bool "Support for extended (non-PC) x86 platforms"
460 default y
461 ---help---
462 If you disable this option then the kernel will only support
463 standard PC platforms. (which covers the vast majority of
464 systems out there.)
465
466 If you enable this option then you'll be able to select support
467 for the following (non-PC) 32 bit x86 platforms:
468 Goldfish (Android emulator)
469 AMD Elan
470 RDC R-321x SoC
471 SGI 320/540 (Visual Workstation)
472 STA2X11-based (e.g. Northville)
473 Moorestown MID devices
474
475 If you have one of these systems, or if you want to build a
476 generic distribution kernel, say Y here - otherwise say N.
477endif
478
479if X86_64
480config X86_EXTENDED_PLATFORM
481 bool "Support for extended (non-PC) x86 platforms"
482 default y
483 ---help---
484 If you disable this option then the kernel will only support
485 standard PC platforms. (which covers the vast majority of
486 systems out there.)
487
488 If you enable this option then you'll be able to select support
489 for the following (non-PC) 64 bit x86 platforms:
490 Numascale NumaChip
491 ScaleMP vSMP
492 SGI Ultraviolet
493
494 If you have one of these systems, or if you want to build a
495 generic distribution kernel, say Y here - otherwise say N.
496endif
497# This is an alphabetically sorted list of 64 bit extended platforms
498# Please maintain the alphabetic order if and when there are additions
499config X86_NUMACHIP
500 bool "Numascale NumaChip"
501 depends on X86_64
502 depends on X86_EXTENDED_PLATFORM
503 depends on NUMA
504 depends on SMP
505 depends on X86_X2APIC
506 depends on PCI_MMCONFIG
507 ---help---
508 Adds support for Numascale NumaChip large-SMP systems. Needed to
509 enable more than ~168 cores.
510 If you don't have one of these, you should say N here.
511
512config X86_VSMP
513 bool "ScaleMP vSMP"
514 select HYPERVISOR_GUEST
515 select PARAVIRT
516 depends on X86_64 && PCI
517 depends on X86_EXTENDED_PLATFORM
518 depends on SMP
519 ---help---
520 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
521 supposed to run on these EM64T-based machines. Only choose this option
522 if you have one of these machines.
523
524config X86_UV
525 bool "SGI Ultraviolet"
526 depends on X86_64
527 depends on X86_EXTENDED_PLATFORM
528 depends on NUMA
529 depends on EFI
530 depends on X86_X2APIC
531 depends on PCI
532 ---help---
533 This option is needed in order to support SGI Ultraviolet systems.
534 If you don't have one of these, you should say N here.
535
536# Following is an alphabetically sorted list of 32 bit extended platforms
537# Please maintain the alphabetic order if and when there are additions
538
539config X86_GOLDFISH
540 bool "Goldfish (Virtual Platform)"
541 depends on X86_EXTENDED_PLATFORM
542 ---help---
543 Enable support for the Goldfish virtual platform used primarily
544 for Android development. Unless you are building for the Android
545 Goldfish emulator say N here.
546
547config X86_INTEL_CE
548 bool "CE4100 TV platform"
549 depends on PCI
550 depends on PCI_GODIRECT
551 depends on X86_IO_APIC
552 depends on X86_32
553 depends on X86_EXTENDED_PLATFORM
554 select X86_REBOOTFIXUPS
555 select OF
556 select OF_EARLY_FLATTREE
557 ---help---
558 Select for the Intel CE media processor (CE4100) SOC.
559 This option compiles in support for the CE4100 SOC for settop
560 boxes and media devices.
561
562config X86_INTEL_MID
563 bool "Intel MID platform support"
564 depends on X86_EXTENDED_PLATFORM
565 depends on X86_PLATFORM_DEVICES
566 depends on PCI
567 depends on X86_64 || (PCI_GOANY && X86_32)
568 depends on X86_IO_APIC
569 select SFI
570 select I2C
571 select DW_APB_TIMER
572 select APB_TIMER
573 select INTEL_SCU_IPC
574 select MFD_INTEL_MSIC
575 ---help---
576 Select to build a kernel capable of supporting Intel MID (Mobile
577 Internet Device) platform systems which do not have the PCI legacy
578 interfaces. If you are building for a PC class system say N here.
579
580 Intel MID platforms are based on an Intel processor and chipset which
581 consume less power than most of the x86 derivatives.
582
583config X86_INTEL_QUARK
584 bool "Intel Quark platform support"
585 depends on X86_32
586 depends on X86_EXTENDED_PLATFORM
587 depends on X86_PLATFORM_DEVICES
588 depends on X86_TSC
589 depends on PCI
590 depends on PCI_GOANY
591 depends on X86_IO_APIC
592 select IOSF_MBI
593 select INTEL_IMR
594 select COMMON_CLK
595 ---help---
596 Select to include support for Quark X1000 SoC.
597 Say Y here if you have a Quark based system such as the Arduino
598 compatible Intel Galileo.
599
600config X86_INTEL_LPSS
601 bool "Intel Low Power Subsystem Support"
602 depends on X86 && ACPI
603 select COMMON_CLK
604 select PINCTRL
605 select IOSF_MBI
606 ---help---
607 Select to build support for Intel Low Power Subsystem such as
608 found on Intel Lynxpoint PCH. Selecting this option enables
609 things like clock tree (common clock framework) and pincontrol
610 which are needed by the LPSS peripheral drivers.
611
612config X86_AMD_PLATFORM_DEVICE
613 bool "AMD ACPI2Platform devices support"
614 depends on ACPI
615 select COMMON_CLK
616 select PINCTRL
617 ---help---
618 Select to interpret AMD specific ACPI device to platform device
619 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
620 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
621 implemented under PINCTRL subsystem.
622
623config IOSF_MBI
624 tristate "Intel SoC IOSF Sideband support for SoC platforms"
625 depends on PCI
626 ---help---
627 This option enables sideband register access support for Intel SoC
628 platforms. On these platforms the IOSF sideband is used in lieu of
629 MSR's for some register accesses, mostly but not limited to thermal
630 and power. Drivers may query the availability of this device to
631 determine if they need the sideband in order to work on these
632 platforms. The sideband is available on the following SoC products.
633 This list is not meant to be exclusive.
634 - BayTrail
635 - Braswell
636 - Quark
637
638 You should say Y if you are running a kernel on one of these SoC's.
639
640config IOSF_MBI_DEBUG
641 bool "Enable IOSF sideband access through debugfs"
642 depends on IOSF_MBI && DEBUG_FS
643 ---help---
644 Select this option to expose the IOSF sideband access registers (MCR,
645 MDR, MCRX) through debugfs to write and read register information from
646 different units on the SoC. This is most useful for obtaining device
647 state information for debug and analysis. As this is a general access
648 mechanism, users of this option would have specific knowledge of the
649 device they want to access.
650
651 If you don't require the option or are in doubt, say N.
652
653config X86_RDC321X
654 bool "RDC R-321x SoC"
655 depends on X86_32
656 depends on X86_EXTENDED_PLATFORM
657 select M486
658 select X86_REBOOTFIXUPS
659 ---help---
660 This option is needed for RDC R-321x system-on-chip, also known
661 as R-8610-(G).
662 If you don't have one of these chips, you should say N here.
663
664config X86_32_NON_STANDARD
665 bool "Support non-standard 32-bit SMP architectures"
666 depends on X86_32 && SMP
667 depends on X86_EXTENDED_PLATFORM
668 ---help---
669 This option compiles in the bigsmp and STA2X11 default
670 subarchitectures. It is intended for a generic binary
671 kernel. If you select them all, kernel will probe it one by
672 one and will fallback to default.
673
674# Alphabetically sorted list of Non standard 32 bit platforms
675
676config X86_SUPPORTS_MEMORY_FAILURE
677 def_bool y
678 # MCE code calls memory_failure():
679 depends on X86_MCE
680 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
681 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
682 depends on X86_64 || !SPARSEMEM
683 select ARCH_SUPPORTS_MEMORY_FAILURE
684
685config STA2X11
686 bool "STA2X11 Companion Chip Support"
687 depends on X86_32_NON_STANDARD && PCI
688 select ARCH_HAS_PHYS_TO_DMA
689 select X86_DEV_DMA_OPS
690 select X86_DMA_REMAP
691 select SWIOTLB
692 select MFD_STA2X11
693 select GPIOLIB
694 default n
695 ---help---
696 This adds support for boards based on the STA2X11 IO-Hub,
697 a.k.a. "ConneXt". The chip is used in place of the standard
698 PC chipset, so all "standard" peripherals are missing. If this
699 option is selected the kernel will still be able to boot on
700 standard PC machines.
701
702config X86_32_IRIS
703 tristate "Eurobraille/Iris poweroff module"
704 depends on X86_32
705 ---help---
706 The Iris machines from EuroBraille do not have APM or ACPI support
707 to shut themselves down properly. A special I/O sequence is
708 needed to do so, which is what this module does at
709 kernel shutdown.
710
711 This is only for Iris machines from EuroBraille.
712
713 If unused, say N.
714
715config SCHED_OMIT_FRAME_POINTER
716 def_bool y
717 prompt "Single-depth WCHAN output"
718 depends on X86
719 ---help---
720 Calculate simpler /proc/<PID>/wchan values. If this option
721 is disabled then wchan values will recurse back to the
722 caller function. This provides more accurate wchan values,
723 at the expense of slightly more scheduling overhead.
724
725 If in doubt, say "Y".
726
727menuconfig HYPERVISOR_GUEST
728 bool "Linux guest support"
729 ---help---
730 Say Y here to enable options for running Linux under various hyper-
731 visors. This option enables basic hypervisor detection and platform
732 setup.
733
734 If you say N, all options in this submenu will be skipped and
735 disabled, and Linux guest support won't be built in.
736
737if HYPERVISOR_GUEST
738
739config PARAVIRT
740 bool "Enable paravirtualization code"
741 ---help---
742 This changes the kernel so it can modify itself when it is run
743 under a hypervisor, potentially improving performance significantly
744 over full virtualization. However, when run without a hypervisor
745 the kernel is theoretically slower and slightly larger.
746
747config PARAVIRT_DEBUG
748 bool "paravirt-ops debugging"
749 depends on PARAVIRT && DEBUG_KERNEL
750 ---help---
751 Enable to debug paravirt_ops internals. Specifically, BUG if
752 a paravirt_op is missing when it is called.
753
754config PARAVIRT_SPINLOCKS
755 bool "Paravirtualization layer for spinlocks"
756 depends on PARAVIRT && SMP
757 ---help---
758 Paravirtualized spinlocks allow a pvops backend to replace the
759 spinlock implementation with something virtualization-friendly
760 (for example, block the virtual CPU rather than spinning).
761
762 It has a minimal impact on native kernels and gives a nice performance
763 benefit on paravirtualized KVM / Xen kernels.
764
765 If you are unsure how to answer this question, answer Y.
766
767config QUEUED_LOCK_STAT
768 bool "Paravirt queued spinlock statistics"
769 depends on PARAVIRT_SPINLOCKS && DEBUG_FS
770 ---help---
771 Enable the collection of statistical data on the slowpath
772 behavior of paravirtualized queued spinlocks and report
773 them on debugfs.
774
775source "arch/x86/xen/Kconfig"
776
777config KVM_GUEST
778 bool "KVM Guest support (including kvmclock)"
779 depends on PARAVIRT
780 select PARAVIRT_CLOCK
781 default y
782 ---help---
783 This option enables various optimizations for running under the KVM
784 hypervisor. It includes a paravirtualized clock, so that instead
785 of relying on a PIT (or probably other) emulation by the
786 underlying device model, the host provides the guest with
787 timing infrastructure such as time of day, and system time
788
789config KVM_DEBUG_FS
790 bool "Enable debug information for KVM Guests in debugfs"
791 depends on KVM_GUEST && DEBUG_FS
792 default n
793 ---help---
794 This option enables collection of various statistics for KVM guest.
795 Statistics are displayed in debugfs filesystem. Enabling this option
796 may incur significant overhead.
797
798config PARAVIRT_TIME_ACCOUNTING
799 bool "Paravirtual steal time accounting"
800 depends on PARAVIRT
801 default n
802 ---help---
803 Select this option to enable fine granularity task steal time
804 accounting. Time spent executing other tasks in parallel with
805 the current vCPU is discounted from the vCPU power. To account for
806 that, there can be a small performance impact.
807
808 If in doubt, say N here.
809
810config PARAVIRT_CLOCK
811 bool
812
813config JAILHOUSE_GUEST
814 bool "Jailhouse non-root cell support"
815 depends on X86_64 && PCI
816 select X86_PM_TIMER
817 ---help---
818 This option allows to run Linux as guest in a Jailhouse non-root
819 cell. You can leave this option disabled if you only want to start
820 Jailhouse and run Linux afterwards in the root cell.
821
822endif #HYPERVISOR_GUEST
823
824config NO_BOOTMEM
825 def_bool y
826
827source "arch/x86/Kconfig.cpu"
828
829config HPET_TIMER
830 def_bool X86_64
831 prompt "HPET Timer Support" if X86_32
832 ---help---
833 Use the IA-PC HPET (High Precision Event Timer) to manage
834 time in preference to the PIT and RTC, if a HPET is
835 present.
836 HPET is the next generation timer replacing legacy 8254s.
837 The HPET provides a stable time base on SMP
838 systems, unlike the TSC, but it is more expensive to access,
839 as it is off-chip. The interface used is documented
840 in the HPET spec, revision 1.
841
842 You can safely choose Y here. However, HPET will only be
843 activated if the platform and the BIOS support this feature.
844 Otherwise the 8254 will be used for timing services.
845
846 Choose N to continue using the legacy 8254 timer.
847
848config HPET_EMULATE_RTC
849 def_bool y
850 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
851
852config APB_TIMER
853 def_bool y if X86_INTEL_MID
854 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
855 select DW_APB_TIMER
856 depends on X86_INTEL_MID && SFI
857 help
858 APB timer is the replacement for 8254, HPET on X86 MID platforms.
859 The APBT provides a stable time base on SMP
860 systems, unlike the TSC, but it is more expensive to access,
861 as it is off-chip. APB timers are always running regardless of CPU
862 C states, they are used as per CPU clockevent device when possible.
863
864# Mark as expert because too many people got it wrong.
865# The code disables itself when not needed.
866config DMI
867 default y
868 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
869 bool "Enable DMI scanning" if EXPERT
870 ---help---
871 Enabled scanning of DMI to identify machine quirks. Say Y
872 here unless you have verified that your setup is not
873 affected by entries in the DMI blacklist. Required by PNP
874 BIOS code.
875
876config GART_IOMMU
877 bool "Old AMD GART IOMMU support"
878 select SWIOTLB
879 depends on X86_64 && PCI && AMD_NB
880 ---help---
881 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
882 GART based hardware IOMMUs.
883
884 The GART supports full DMA access for devices with 32-bit access
885 limitations, on systems with more than 3 GB. This is usually needed
886 for USB, sound, many IDE/SATA chipsets and some other devices.
887
888 Newer systems typically have a modern AMD IOMMU, supported via
889 the CONFIG_AMD_IOMMU=y config option.
890
891 In normal configurations this driver is only active when needed:
892 there's more than 3 GB of memory and the system contains a
893 32-bit limited device.
894
895 If unsure, say Y.
896
897config CALGARY_IOMMU
898 bool "IBM Calgary IOMMU support"
899 select SWIOTLB
900 depends on X86_64 && PCI
901 ---help---
902 Support for hardware IOMMUs in IBM's xSeries x366 and x460
903 systems. Needed to run systems with more than 3GB of memory
904 properly with 32-bit PCI devices that do not support DAC
905 (Double Address Cycle). Calgary also supports bus level
906 isolation, where all DMAs pass through the IOMMU. This
907 prevents them from going anywhere except their intended
908 destination. This catches hard-to-find kernel bugs and
909 mis-behaving drivers and devices that do not use the DMA-API
910 properly to set up their DMA buffers. The IOMMU can be
911 turned off at boot time with the iommu=off parameter.
912 Normally the kernel will make the right choice by itself.
913 If unsure, say Y.
914
915config CALGARY_IOMMU_ENABLED_BY_DEFAULT
916 def_bool y
917 prompt "Should Calgary be enabled by default?"
918 depends on CALGARY_IOMMU
919 ---help---
920 Should Calgary be enabled by default? if you choose 'y', Calgary
921 will be used (if it exists). If you choose 'n', Calgary will not be
922 used even if it exists. If you choose 'n' and would like to use
923 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
924 If unsure, say Y.
925
926# need this always selected by IOMMU for the VIA workaround
927config SWIOTLB
928 def_bool y if X86_64
929 ---help---
930 Support for software bounce buffers used on x86-64 systems
931 which don't have a hardware IOMMU. Using this PCI devices
932 which can only access 32-bits of memory can be used on systems
933 with more than 3 GB of memory.
934 If unsure, say Y.
935
936config IOMMU_HELPER
937 def_bool y
938 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
939
940config MAXSMP
941 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
942 depends on X86_64 && SMP && DEBUG_KERNEL
943 select CPUMASK_OFFSTACK
944 ---help---
945 Enable maximum number of CPUS and NUMA Nodes for this architecture.
946 If unsure, say N.
947
948#
949# The maximum number of CPUs supported:
950#
951# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
952# and which can be configured interactively in the
953# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
954#
955# The ranges are different on 32-bit and 64-bit kernels, depending on
956# hardware capabilities and scalability features of the kernel.
957#
958# ( If MAXSMP is enabled we just use the highest possible value and disable
959# interactive configuration. )
960#
961
962config NR_CPUS_RANGE_BEGIN
963 int
964 default NR_CPUS_RANGE_END if MAXSMP
965 default 1 if !SMP
966 default 2
967
968config NR_CPUS_RANGE_END
969 int
970 depends on X86_32
971 default 64 if SMP && X86_BIGSMP
972 default 8 if SMP && !X86_BIGSMP
973 default 1 if !SMP
974
975config NR_CPUS_RANGE_END
976 int
977 depends on X86_64
978 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK)
979 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
980 default 1 if !SMP
981
982config NR_CPUS_DEFAULT
983 int
984 depends on X86_32
985 default 32 if X86_BIGSMP
986 default 8 if SMP
987 default 1 if !SMP
988
989config NR_CPUS_DEFAULT
990 int
991 depends on X86_64
992 default 8192 if MAXSMP
993 default 64 if SMP
994 default 1 if !SMP
995
996config NR_CPUS
997 int "Maximum number of CPUs" if SMP && !MAXSMP
998 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
999 default NR_CPUS_DEFAULT
1000 ---help---
1001 This allows you to specify the maximum number of CPUs which this
1002 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
1003 supported value is 8192, otherwise the maximum value is 512. The
1004 minimum value which makes sense is 2.
1005
1006 This is purely to save memory: each supported CPU adds about 8KB
1007 to the kernel image.
1008
1009config SCHED_SMT
1010 bool "SMT (Hyperthreading) scheduler support"
1011 depends on SMP
1012 ---help---
1013 SMT scheduler support improves the CPU scheduler's decision making
1014 when dealing with Intel Pentium 4 chips with HyperThreading at a
1015 cost of slightly increased overhead in some places. If unsure say
1016 N here.
1017
1018config SCHED_MC
1019 def_bool y
1020 prompt "Multi-core scheduler support"
1021 depends on SMP
1022 ---help---
1023 Multi-core scheduler support improves the CPU scheduler's decision
1024 making when dealing with multi-core CPU chips at a cost of slightly
1025 increased overhead in some places. If unsure say N here.
1026
1027config SCHED_MC_PRIO
1028 bool "CPU core priorities scheduler support"
1029 depends on SCHED_MC && CPU_SUP_INTEL
1030 select X86_INTEL_PSTATE
1031 select CPU_FREQ
1032 default y
1033 ---help---
1034 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1035 core ordering determined at manufacturing time, which allows
1036 certain cores to reach higher turbo frequencies (when running
1037 single threaded workloads) than others.
1038
1039 Enabling this kernel feature teaches the scheduler about
1040 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1041 scheduler's CPU selection logic accordingly, so that higher
1042 overall system performance can be achieved.
1043
1044 This feature will have no effect on CPUs without this feature.
1045
1046 If unsure say Y here.
1047
1048source "kernel/Kconfig.preempt"
1049
1050config UP_LATE_INIT
1051 def_bool y
1052 depends on !SMP && X86_LOCAL_APIC
1053
1054config X86_UP_APIC
1055 bool "Local APIC support on uniprocessors" if !PCI_MSI
1056 default PCI_MSI
1057 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1058 ---help---
1059 A local APIC (Advanced Programmable Interrupt Controller) is an
1060 integrated interrupt controller in the CPU. If you have a single-CPU
1061 system which has a processor with a local APIC, you can say Y here to
1062 enable and use it. If you say Y here even though your machine doesn't
1063 have a local APIC, then the kernel will still run with no slowdown at
1064 all. The local APIC supports CPU-generated self-interrupts (timer,
1065 performance counters), and the NMI watchdog which detects hard
1066 lockups.
1067
1068config X86_UP_IOAPIC
1069 bool "IO-APIC support on uniprocessors"
1070 depends on X86_UP_APIC
1071 ---help---
1072 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1073 SMP-capable replacement for PC-style interrupt controllers. Most
1074 SMP systems and many recent uniprocessor systems have one.
1075
1076 If you have a single-CPU system with an IO-APIC, you can say Y here
1077 to use it. If you say Y here even though your machine doesn't have
1078 an IO-APIC, then the kernel will still run with no slowdown at all.
1079
1080config X86_LOCAL_APIC
1081 def_bool y
1082 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1083 select IRQ_DOMAIN_HIERARCHY
1084 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1085
1086config X86_IO_APIC
1087 def_bool y
1088 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1089
1090config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1091 bool "Reroute for broken boot IRQs"
1092 depends on X86_IO_APIC
1093 ---help---
1094 This option enables a workaround that fixes a source of
1095 spurious interrupts. This is recommended when threaded
1096 interrupt handling is used on systems where the generation of
1097 superfluous "boot interrupts" cannot be disabled.
1098
1099 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1100 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1101 kernel does during interrupt handling). On chipsets where this
1102 boot IRQ generation cannot be disabled, this workaround keeps
1103 the original IRQ line masked so that only the equivalent "boot
1104 IRQ" is delivered to the CPUs. The workaround also tells the
1105 kernel to set up the IRQ handler on the boot IRQ line. In this
1106 way only one interrupt is delivered to the kernel. Otherwise
1107 the spurious second interrupt may cause the kernel to bring
1108 down (vital) interrupt lines.
1109
1110 Only affects "broken" chipsets. Interrupt sharing may be
1111 increased on these systems.
1112
1113config X86_MCE
1114 bool "Machine Check / overheating reporting"
1115 select GENERIC_ALLOCATOR
1116 default y
1117 ---help---
1118 Machine Check support allows the processor to notify the
1119 kernel if it detects a problem (e.g. overheating, data corruption).
1120 The action the kernel takes depends on the severity of the problem,
1121 ranging from warning messages to halting the machine.
1122
1123config X86_MCELOG_LEGACY
1124 bool "Support for deprecated /dev/mcelog character device"
1125 depends on X86_MCE
1126 ---help---
1127 Enable support for /dev/mcelog which is needed by the old mcelog
1128 userspace logging daemon. Consider switching to the new generation
1129 rasdaemon solution.
1130
1131config X86_MCE_INTEL
1132 def_bool y
1133 prompt "Intel MCE features"
1134 depends on X86_MCE && X86_LOCAL_APIC
1135 ---help---
1136 Additional support for intel specific MCE features such as
1137 the thermal monitor.
1138
1139config X86_MCE_AMD
1140 def_bool y
1141 prompt "AMD MCE features"
1142 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1143 ---help---
1144 Additional support for AMD specific MCE features such as
1145 the DRAM Error Threshold.
1146
1147config X86_ANCIENT_MCE
1148 bool "Support for old Pentium 5 / WinChip machine checks"
1149 depends on X86_32 && X86_MCE
1150 ---help---
1151 Include support for machine check handling on old Pentium 5 or WinChip
1152 systems. These typically need to be enabled explicitly on the command
1153 line.
1154
1155config X86_MCE_THRESHOLD
1156 depends on X86_MCE_AMD || X86_MCE_INTEL
1157 def_bool y
1158
1159config X86_MCE_INJECT
1160 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1161 tristate "Machine check injector support"
1162 ---help---
1163 Provide support for injecting machine checks for testing purposes.
1164 If you don't know what a machine check is and you don't do kernel
1165 QA it is safe to say n.
1166
1167config X86_THERMAL_VECTOR
1168 def_bool y
1169 depends on X86_MCE_INTEL
1170
1171source "arch/x86/events/Kconfig"
1172
1173config X86_LEGACY_VM86
1174 bool "Legacy VM86 support"
1175 default n
1176 depends on X86_32
1177 ---help---
1178 This option allows user programs to put the CPU into V8086
1179 mode, which is an 80286-era approximation of 16-bit real mode.
1180
1181 Some very old versions of X and/or vbetool require this option
1182 for user mode setting. Similarly, DOSEMU will use it if
1183 available to accelerate real mode DOS programs. However, any
1184 recent version of DOSEMU, X, or vbetool should be fully
1185 functional even without kernel VM86 support, as they will all
1186 fall back to software emulation. Nevertheless, if you are using
1187 a 16-bit DOS program where 16-bit performance matters, vm86
1188 mode might be faster than emulation and you might want to
1189 enable this option.
1190
1191 Note that any app that works on a 64-bit kernel is unlikely to
1192 need this option, as 64-bit kernels don't, and can't, support
1193 V8086 mode. This option is also unrelated to 16-bit protected
1194 mode and is not needed to run most 16-bit programs under Wine.
1195
1196 Enabling this option increases the complexity of the kernel
1197 and slows down exception handling a tiny bit.
1198
1199 If unsure, say N here.
1200
1201config VM86
1202 bool
1203 default X86_LEGACY_VM86
1204
1205config X86_16BIT
1206 bool "Enable support for 16-bit segments" if EXPERT
1207 default y
1208 depends on MODIFY_LDT_SYSCALL
1209 ---help---
1210 This option is required by programs like Wine to run 16-bit
1211 protected mode legacy code on x86 processors. Disabling
1212 this option saves about 300 bytes on i386, or around 6K text
1213 plus 16K runtime memory on x86-64,
1214
1215config X86_ESPFIX32
1216 def_bool y
1217 depends on X86_16BIT && X86_32
1218
1219config X86_ESPFIX64
1220 def_bool y
1221 depends on X86_16BIT && X86_64
1222
1223config X86_VSYSCALL_EMULATION
1224 bool "Enable vsyscall emulation" if EXPERT
1225 default y
1226 depends on X86_64
1227 ---help---
1228 This enables emulation of the legacy vsyscall page. Disabling
1229 it is roughly equivalent to booting with vsyscall=none, except
1230 that it will also disable the helpful warning if a program
1231 tries to use a vsyscall. With this option set to N, offending
1232 programs will just segfault, citing addresses of the form
1233 0xffffffffff600?00.
1234
1235 This option is required by many programs built before 2013, and
1236 care should be used even with newer programs if set to N.
1237
1238 Disabling this option saves about 7K of kernel size and
1239 possibly 4K of additional runtime pagetable memory.
1240
1241config TOSHIBA
1242 tristate "Toshiba Laptop support"
1243 depends on X86_32
1244 ---help---
1245 This adds a driver to safely access the System Management Mode of
1246 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1247 not work on models with a Phoenix BIOS. The System Management Mode
1248 is used to set the BIOS and power saving options on Toshiba portables.
1249
1250 For information on utilities to make use of this driver see the
1251 Toshiba Linux utilities web site at:
1252 <http://www.buzzard.org.uk/toshiba/>.
1253
1254 Say Y if you intend to run this kernel on a Toshiba portable.
1255 Say N otherwise.
1256
1257config I8K
1258 tristate "Dell i8k legacy laptop support"
1259 select HWMON
1260 select SENSORS_DELL_SMM
1261 ---help---
1262 This option enables legacy /proc/i8k userspace interface in hwmon
1263 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1264 temperature and allows controlling fan speeds of Dell laptops via
1265 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1266 it reports also power and hotkey status. For fan speed control is
1267 needed userspace package i8kutils.
1268
1269 Say Y if you intend to run this kernel on old Dell laptops or want to
1270 use userspace package i8kutils.
1271 Say N otherwise.
1272
1273config X86_REBOOTFIXUPS
1274 bool "Enable X86 board specific fixups for reboot"
1275 depends on X86_32
1276 ---help---
1277 This enables chipset and/or board specific fixups to be done
1278 in order to get reboot to work correctly. This is only needed on
1279 some combinations of hardware and BIOS. The symptom, for which
1280 this config is intended, is when reboot ends with a stalled/hung
1281 system.
1282
1283 Currently, the only fixup is for the Geode machines using
1284 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1285
1286 Say Y if you want to enable the fixup. Currently, it's safe to
1287 enable this option even if you don't need it.
1288 Say N otherwise.
1289
1290config MICROCODE
1291 bool "CPU microcode loading support"
1292 default y
1293 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1294 select FW_LOADER
1295 ---help---
1296 If you say Y here, you will be able to update the microcode on
1297 Intel and AMD processors. The Intel support is for the IA32 family,
1298 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1299 AMD support is for families 0x10 and later. You will obviously need
1300 the actual microcode binary data itself which is not shipped with
1301 the Linux kernel.
1302
1303 The preferred method to load microcode from a detached initrd is described
1304 in Documentation/x86/microcode.txt. For that you need to enable
1305 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1306 initrd for microcode blobs.
1307
1308 In addition, you can build the microcode into the kernel. For that you
1309 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1310 config option.
1311
1312config MICROCODE_INTEL
1313 bool "Intel microcode loading support"
1314 depends on MICROCODE
1315 default MICROCODE
1316 select FW_LOADER
1317 ---help---
1318 This options enables microcode patch loading support for Intel
1319 processors.
1320
1321 For the current Intel microcode data package go to
1322 <https://downloadcenter.intel.com> and search for
1323 'Linux Processor Microcode Data File'.
1324
1325config MICROCODE_AMD
1326 bool "AMD microcode loading support"
1327 depends on MICROCODE
1328 select FW_LOADER
1329 ---help---
1330 If you select this option, microcode patch loading support for AMD
1331 processors will be enabled.
1332
1333config MICROCODE_OLD_INTERFACE
1334 def_bool y
1335 depends on MICROCODE
1336
1337config X86_MSR
1338 tristate "/dev/cpu/*/msr - Model-specific register support"
1339 ---help---
1340 This device gives privileged processes access to the x86
1341 Model-Specific Registers (MSRs). It is a character device with
1342 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1343 MSR accesses are directed to a specific CPU on multi-processor
1344 systems.
1345
1346config X86_CPUID
1347 tristate "/dev/cpu/*/cpuid - CPU information support"
1348 ---help---
1349 This device gives processes access to the x86 CPUID instruction to
1350 be executed on a specific processor. It is a character device
1351 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1352 /dev/cpu/31/cpuid.
1353
1354choice
1355 prompt "High Memory Support"
1356 default HIGHMEM4G
1357 depends on X86_32
1358
1359config NOHIGHMEM
1360 bool "off"
1361 ---help---
1362 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1363 However, the address space of 32-bit x86 processors is only 4
1364 Gigabytes large. That means that, if you have a large amount of
1365 physical memory, not all of it can be "permanently mapped" by the
1366 kernel. The physical memory that's not permanently mapped is called
1367 "high memory".
1368
1369 If you are compiling a kernel which will never run on a machine with
1370 more than 1 Gigabyte total physical RAM, answer "off" here (default
1371 choice and suitable for most users). This will result in a "3GB/1GB"
1372 split: 3GB are mapped so that each process sees a 3GB virtual memory
1373 space and the remaining part of the 4GB virtual memory space is used
1374 by the kernel to permanently map as much physical memory as
1375 possible.
1376
1377 If the machine has between 1 and 4 Gigabytes physical RAM, then
1378 answer "4GB" here.
1379
1380 If more than 4 Gigabytes is used then answer "64GB" here. This
1381 selection turns Intel PAE (Physical Address Extension) mode on.
1382 PAE implements 3-level paging on IA32 processors. PAE is fully
1383 supported by Linux, PAE mode is implemented on all recent Intel
1384 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1385 then the kernel will not boot on CPUs that don't support PAE!
1386
1387 The actual amount of total physical memory will either be
1388 auto detected or can be forced by using a kernel command line option
1389 such as "mem=256M". (Try "man bootparam" or see the documentation of
1390 your boot loader (lilo or loadlin) about how to pass options to the
1391 kernel at boot time.)
1392
1393 If unsure, say "off".
1394
1395config HIGHMEM4G
1396 bool "4GB"
1397 ---help---
1398 Select this if you have a 32-bit processor and between 1 and 4
1399 gigabytes of physical RAM.
1400
1401config HIGHMEM64G
1402 bool "64GB"
1403 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1404 select X86_PAE
1405 ---help---
1406 Select this if you have a 32-bit processor and more than 4
1407 gigabytes of physical RAM.
1408
1409endchoice
1410
1411choice
1412 prompt "Memory split" if EXPERT
1413 default VMSPLIT_3G
1414 depends on X86_32
1415 ---help---
1416 Select the desired split between kernel and user memory.
1417
1418 If the address range available to the kernel is less than the
1419 physical memory installed, the remaining memory will be available
1420 as "high memory". Accessing high memory is a little more costly
1421 than low memory, as it needs to be mapped into the kernel first.
1422 Note that increasing the kernel address space limits the range
1423 available to user programs, making the address space there
1424 tighter. Selecting anything other than the default 3G/1G split
1425 will also likely make your kernel incompatible with binary-only
1426 kernel modules.
1427
1428 If you are not absolutely sure what you are doing, leave this
1429 option alone!
1430
1431 config VMSPLIT_3G
1432 bool "3G/1G user/kernel split"
1433 config VMSPLIT_3G_OPT
1434 depends on !X86_PAE
1435 bool "3G/1G user/kernel split (for full 1G low memory)"
1436 config VMSPLIT_2G
1437 bool "2G/2G user/kernel split"
1438 config VMSPLIT_2G_OPT
1439 depends on !X86_PAE
1440 bool "2G/2G user/kernel split (for full 2G low memory)"
1441 config VMSPLIT_1G
1442 bool "1G/3G user/kernel split"
1443endchoice
1444
1445config PAGE_OFFSET
1446 hex
1447 default 0xB0000000 if VMSPLIT_3G_OPT
1448 default 0x80000000 if VMSPLIT_2G
1449 default 0x78000000 if VMSPLIT_2G_OPT
1450 default 0x40000000 if VMSPLIT_1G
1451 default 0xC0000000
1452 depends on X86_32
1453
1454config HIGHMEM
1455 def_bool y
1456 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1457
1458config X86_PAE
1459 bool "PAE (Physical Address Extension) Support"
1460 depends on X86_32 && !HIGHMEM4G
1461 select SWIOTLB
1462 ---help---
1463 PAE is required for NX support, and furthermore enables
1464 larger swapspace support for non-overcommit purposes. It
1465 has the cost of more pagetable lookup overhead, and also
1466 consumes more pagetable space per process.
1467
1468config X86_5LEVEL
1469 bool "Enable 5-level page tables support"
1470 select DYNAMIC_MEMORY_LAYOUT
1471 select SPARSEMEM_VMEMMAP
1472 depends on X86_64
1473 ---help---
1474 5-level paging enables access to larger address space:
1475 upto 128 PiB of virtual address space and 4 PiB of
1476 physical address space.
1477
1478 It will be supported by future Intel CPUs.
1479
1480 A kernel with the option enabled can be booted on machines that
1481 support 4- or 5-level paging.
1482
1483 See Documentation/x86/x86_64/5level-paging.txt for more
1484 information.
1485
1486 Say N if unsure.
1487
1488config ARCH_PHYS_ADDR_T_64BIT
1489 def_bool y
1490 depends on X86_64 || X86_PAE
1491
1492config ARCH_DMA_ADDR_T_64BIT
1493 def_bool y
1494 depends on X86_64 || HIGHMEM64G
1495
1496config X86_DIRECT_GBPAGES
1497 def_bool y
1498 depends on X86_64 && !DEBUG_PAGEALLOC
1499 ---help---
1500 Certain kernel features effectively disable kernel
1501 linear 1 GB mappings (even if the CPU otherwise
1502 supports them), so don't confuse the user by printing
1503 that we have them enabled.
1504
1505config ARCH_HAS_MEM_ENCRYPT
1506 def_bool y
1507
1508config AMD_MEM_ENCRYPT
1509 bool "AMD Secure Memory Encryption (SME) support"
1510 depends on X86_64 && CPU_SUP_AMD
1511 ---help---
1512 Say yes to enable support for the encryption of system memory.
1513 This requires an AMD processor that supports Secure Memory
1514 Encryption (SME).
1515
1516config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1517 bool "Activate AMD Secure Memory Encryption (SME) by default"
1518 default y
1519 depends on AMD_MEM_ENCRYPT
1520 ---help---
1521 Say yes to have system memory encrypted by default if running on
1522 an AMD processor that supports Secure Memory Encryption (SME).
1523
1524 If set to Y, then the encryption of system memory can be
1525 deactivated with the mem_encrypt=off command line option.
1526
1527 If set to N, then the encryption of system memory can be
1528 activated with the mem_encrypt=on command line option.
1529
1530config ARCH_USE_MEMREMAP_PROT
1531 def_bool y
1532 depends on AMD_MEM_ENCRYPT
1533
1534# Common NUMA Features
1535config NUMA
1536 bool "Numa Memory Allocation and Scheduler Support"
1537 depends on SMP
1538 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1539 default y if X86_BIGSMP
1540 ---help---
1541 Enable NUMA (Non Uniform Memory Access) support.
1542
1543 The kernel will try to allocate memory used by a CPU on the
1544 local memory controller of the CPU and add some more
1545 NUMA awareness to the kernel.
1546
1547 For 64-bit this is recommended if the system is Intel Core i7
1548 (or later), AMD Opteron, or EM64T NUMA.
1549
1550 For 32-bit this is only needed if you boot a 32-bit
1551 kernel on a 64-bit NUMA platform.
1552
1553 Otherwise, you should say N.
1554
1555config AMD_NUMA
1556 def_bool y
1557 prompt "Old style AMD Opteron NUMA detection"
1558 depends on X86_64 && NUMA && PCI
1559 ---help---
1560 Enable AMD NUMA node topology detection. You should say Y here if
1561 you have a multi processor AMD system. This uses an old method to
1562 read the NUMA configuration directly from the builtin Northbridge
1563 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1564 which also takes priority if both are compiled in.
1565
1566config X86_64_ACPI_NUMA
1567 def_bool y
1568 prompt "ACPI NUMA detection"
1569 depends on X86_64 && NUMA && ACPI && PCI
1570 select ACPI_NUMA
1571 ---help---
1572 Enable ACPI SRAT based node topology detection.
1573
1574# Some NUMA nodes have memory ranges that span
1575# other nodes. Even though a pfn is valid and
1576# between a node's start and end pfns, it may not
1577# reside on that node. See memmap_init_zone()
1578# for details.
1579config NODES_SPAN_OTHER_NODES
1580 def_bool y
1581 depends on X86_64_ACPI_NUMA
1582
1583config NUMA_EMU
1584 bool "NUMA emulation"
1585 depends on NUMA
1586 ---help---
1587 Enable NUMA emulation. A flat machine will be split
1588 into virtual nodes when booted with "numa=fake=N", where N is the
1589 number of nodes. This is only useful for debugging.
1590
1591config NODES_SHIFT
1592 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1593 range 1 10
1594 default "10" if MAXSMP
1595 default "6" if X86_64
1596 default "3"
1597 depends on NEED_MULTIPLE_NODES
1598 ---help---
1599 Specify the maximum number of NUMA Nodes available on the target
1600 system. Increases memory reserved to accommodate various tables.
1601
1602config ARCH_HAVE_MEMORY_PRESENT
1603 def_bool y
1604 depends on X86_32 && DISCONTIGMEM
1605
1606config ARCH_FLATMEM_ENABLE
1607 def_bool y
1608 depends on X86_32 && !NUMA
1609
1610config ARCH_DISCONTIGMEM_ENABLE
1611 def_bool y
1612 depends on NUMA && X86_32
1613
1614config ARCH_DISCONTIGMEM_DEFAULT
1615 def_bool y
1616 depends on NUMA && X86_32
1617
1618config ARCH_SPARSEMEM_ENABLE
1619 def_bool y
1620 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1621 select SPARSEMEM_STATIC if X86_32
1622 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1623
1624config ARCH_SPARSEMEM_DEFAULT
1625 def_bool y
1626 depends on X86_64
1627
1628config ARCH_SELECT_MEMORY_MODEL
1629 def_bool y
1630 depends on ARCH_SPARSEMEM_ENABLE
1631
1632config ARCH_MEMORY_PROBE
1633 bool "Enable sysfs memory/probe interface"
1634 depends on X86_64 && MEMORY_HOTPLUG
1635 help
1636 This option enables a sysfs memory/probe interface for testing.
1637 See Documentation/memory-hotplug.txt for more information.
1638 If you are unsure how to answer this question, answer N.
1639
1640config ARCH_PROC_KCORE_TEXT
1641 def_bool y
1642 depends on X86_64 && PROC_KCORE
1643
1644config ILLEGAL_POINTER_VALUE
1645 hex
1646 default 0 if X86_32
1647 default 0xdead000000000000 if X86_64
1648
1649source "mm/Kconfig"
1650
1651config X86_PMEM_LEGACY_DEVICE
1652 bool
1653
1654config X86_PMEM_LEGACY
1655 tristate "Support non-standard NVDIMMs and ADR protected memory"
1656 depends on PHYS_ADDR_T_64BIT
1657 depends on BLK_DEV
1658 select X86_PMEM_LEGACY_DEVICE
1659 select LIBNVDIMM
1660 help
1661 Treat memory marked using the non-standard e820 type of 12 as used
1662 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1663 The kernel will offer these regions to the 'pmem' driver so
1664 they can be used for persistent storage.
1665
1666 Say Y if unsure.
1667
1668config HIGHPTE
1669 bool "Allocate 3rd-level pagetables from highmem"
1670 depends on HIGHMEM
1671 ---help---
1672 The VM uses one page table entry for each page of physical memory.
1673 For systems with a lot of RAM, this can be wasteful of precious
1674 low memory. Setting this option will put user-space page table
1675 entries in high memory.
1676
1677config X86_CHECK_BIOS_CORRUPTION
1678 bool "Check for low memory corruption"
1679 ---help---
1680 Periodically check for memory corruption in low memory, which
1681 is suspected to be caused by BIOS. Even when enabled in the
1682 configuration, it is disabled at runtime. Enable it by
1683 setting "memory_corruption_check=1" on the kernel command
1684 line. By default it scans the low 64k of memory every 60
1685 seconds; see the memory_corruption_check_size and
1686 memory_corruption_check_period parameters in
1687 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1688
1689 When enabled with the default parameters, this option has
1690 almost no overhead, as it reserves a relatively small amount
1691 of memory and scans it infrequently. It both detects corruption
1692 and prevents it from affecting the running system.
1693
1694 It is, however, intended as a diagnostic tool; if repeatable
1695 BIOS-originated corruption always affects the same memory,
1696 you can use memmap= to prevent the kernel from using that
1697 memory.
1698
1699config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1700 bool "Set the default setting of memory_corruption_check"
1701 depends on X86_CHECK_BIOS_CORRUPTION
1702 default y
1703 ---help---
1704 Set whether the default state of memory_corruption_check is
1705 on or off.
1706
1707config X86_RESERVE_LOW
1708 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1709 default 64
1710 range 4 640
1711 ---help---
1712 Specify the amount of low memory to reserve for the BIOS.
1713
1714 The first page contains BIOS data structures that the kernel
1715 must not use, so that page must always be reserved.
1716
1717 By default we reserve the first 64K of physical RAM, as a
1718 number of BIOSes are known to corrupt that memory range
1719 during events such as suspend/resume or monitor cable
1720 insertion, so it must not be used by the kernel.
1721
1722 You can set this to 4 if you are absolutely sure that you
1723 trust the BIOS to get all its memory reservations and usages
1724 right. If you know your BIOS have problems beyond the
1725 default 64K area, you can set this to 640 to avoid using the
1726 entire low memory range.
1727
1728 If you have doubts about the BIOS (e.g. suspend/resume does
1729 not work or there's kernel crashes after certain hardware
1730 hotplug events) then you might want to enable
1731 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1732 typical corruption patterns.
1733
1734 Leave this to the default value of 64 if you are unsure.
1735
1736config MATH_EMULATION
1737 bool
1738 depends on MODIFY_LDT_SYSCALL
1739 prompt "Math emulation" if X86_32
1740 ---help---
1741 Linux can emulate a math coprocessor (used for floating point
1742 operations) if you don't have one. 486DX and Pentium processors have
1743 a math coprocessor built in, 486SX and 386 do not, unless you added
1744 a 487DX or 387, respectively. (The messages during boot time can
1745 give you some hints here ["man dmesg"].) Everyone needs either a
1746 coprocessor or this emulation.
1747
1748 If you don't have a math coprocessor, you need to say Y here; if you
1749 say Y here even though you have a coprocessor, the coprocessor will
1750 be used nevertheless. (This behavior can be changed with the kernel
1751 command line option "no387", which comes handy if your coprocessor
1752 is broken. Try "man bootparam" or see the documentation of your boot
1753 loader (lilo or loadlin) about how to pass options to the kernel at
1754 boot time.) This means that it is a good idea to say Y here if you
1755 intend to use this kernel on different machines.
1756
1757 More information about the internals of the Linux math coprocessor
1758 emulation can be found in <file:arch/x86/math-emu/README>.
1759
1760 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1761 kernel, it won't hurt.
1762
1763config MTRR
1764 def_bool y
1765 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1766 ---help---
1767 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1768 the Memory Type Range Registers (MTRRs) may be used to control
1769 processor access to memory ranges. This is most useful if you have
1770 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1771 allows bus write transfers to be combined into a larger transfer
1772 before bursting over the PCI/AGP bus. This can increase performance
1773 of image write operations 2.5 times or more. Saying Y here creates a
1774 /proc/mtrr file which may be used to manipulate your processor's
1775 MTRRs. Typically the X server should use this.
1776
1777 This code has a reasonably generic interface so that similar
1778 control registers on other processors can be easily supported
1779 as well:
1780
1781 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1782 Registers (ARRs) which provide a similar functionality to MTRRs. For
1783 these, the ARRs are used to emulate the MTRRs.
1784 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1785 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1786 write-combining. All of these processors are supported by this code
1787 and it makes sense to say Y here if you have one of them.
1788
1789 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1790 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1791 can lead to all sorts of problems, so it's good to say Y here.
1792
1793 You can safely say Y even if your machine doesn't have MTRRs, you'll
1794 just add about 9 KB to your kernel.
1795
1796 See <file:Documentation/x86/mtrr.txt> for more information.
1797
1798config MTRR_SANITIZER
1799 def_bool y
1800 prompt "MTRR cleanup support"
1801 depends on MTRR
1802 ---help---
1803 Convert MTRR layout from continuous to discrete, so X drivers can
1804 add writeback entries.
1805
1806 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1807 The largest mtrr entry size for a continuous block can be set with
1808 mtrr_chunk_size.
1809
1810 If unsure, say Y.
1811
1812config MTRR_SANITIZER_ENABLE_DEFAULT
1813 int "MTRR cleanup enable value (0-1)"
1814 range 0 1
1815 default "0"
1816 depends on MTRR_SANITIZER
1817 ---help---
1818 Enable mtrr cleanup default value
1819
1820config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1821 int "MTRR cleanup spare reg num (0-7)"
1822 range 0 7
1823 default "1"
1824 depends on MTRR_SANITIZER
1825 ---help---
1826 mtrr cleanup spare entries default, it can be changed via
1827 mtrr_spare_reg_nr=N on the kernel command line.
1828
1829config X86_PAT
1830 def_bool y
1831 prompt "x86 PAT support" if EXPERT
1832 depends on MTRR
1833 ---help---
1834 Use PAT attributes to setup page level cache control.
1835
1836 PATs are the modern equivalents of MTRRs and are much more
1837 flexible than MTRRs.
1838
1839 Say N here if you see bootup problems (boot crash, boot hang,
1840 spontaneous reboots) or a non-working video driver.
1841
1842 If unsure, say Y.
1843
1844config ARCH_USES_PG_UNCACHED
1845 def_bool y
1846 depends on X86_PAT
1847
1848config ARCH_RANDOM
1849 def_bool y
1850 prompt "x86 architectural random number generator" if EXPERT
1851 ---help---
1852 Enable the x86 architectural RDRAND instruction
1853 (Intel Bull Mountain technology) to generate random numbers.
1854 If supported, this is a high bandwidth, cryptographically
1855 secure hardware random number generator.
1856
1857config X86_SMAP
1858 def_bool y
1859 prompt "Supervisor Mode Access Prevention" if EXPERT
1860 ---help---
1861 Supervisor Mode Access Prevention (SMAP) is a security
1862 feature in newer Intel processors. There is a small
1863 performance cost if this enabled and turned on; there is
1864 also a small increase in the kernel size if this is enabled.
1865
1866 If unsure, say Y.
1867
1868config X86_INTEL_UMIP
1869 def_bool y
1870 depends on CPU_SUP_INTEL
1871 prompt "Intel User Mode Instruction Prevention" if EXPERT
1872 ---help---
1873 The User Mode Instruction Prevention (UMIP) is a security
1874 feature in newer Intel processors. If enabled, a general
1875 protection fault is issued if the SGDT, SLDT, SIDT, SMSW
1876 or STR instructions are executed in user mode. These instructions
1877 unnecessarily expose information about the hardware state.
1878
1879 The vast majority of applications do not use these instructions.
1880 For the very few that do, software emulation is provided in
1881 specific cases in protected and virtual-8086 modes. Emulated
1882 results are dummy.
1883
1884config X86_INTEL_MPX
1885 prompt "Intel MPX (Memory Protection Extensions)"
1886 def_bool n
1887 # Note: only available in 64-bit mode due to VMA flags shortage
1888 depends on CPU_SUP_INTEL && X86_64
1889 select ARCH_USES_HIGH_VMA_FLAGS
1890 ---help---
1891 MPX provides hardware features that can be used in
1892 conjunction with compiler-instrumented code to check
1893 memory references. It is designed to detect buffer
1894 overflow or underflow bugs.
1895
1896 This option enables running applications which are
1897 instrumented or otherwise use MPX. It does not use MPX
1898 itself inside the kernel or to protect the kernel
1899 against bad memory references.
1900
1901 Enabling this option will make the kernel larger:
1902 ~8k of kernel text and 36 bytes of data on a 64-bit
1903 defconfig. It adds a long to the 'mm_struct' which
1904 will increase the kernel memory overhead of each
1905 process and adds some branches to paths used during
1906 exec() and munmap().
1907
1908 For details, see Documentation/x86/intel_mpx.txt
1909
1910 If unsure, say N.
1911
1912config X86_INTEL_MEMORY_PROTECTION_KEYS
1913 prompt "Intel Memory Protection Keys"
1914 def_bool y
1915 # Note: only available in 64-bit mode
1916 depends on CPU_SUP_INTEL && X86_64
1917 select ARCH_USES_HIGH_VMA_FLAGS
1918 select ARCH_HAS_PKEYS
1919 ---help---
1920 Memory Protection Keys provides a mechanism for enforcing
1921 page-based protections, but without requiring modification of the
1922 page tables when an application changes protection domains.
1923
1924 For details, see Documentation/x86/protection-keys.txt
1925
1926 If unsure, say y.
1927
1928config EFI
1929 bool "EFI runtime service support"
1930 depends on ACPI
1931 select UCS2_STRING
1932 select EFI_RUNTIME_WRAPPERS
1933 ---help---
1934 This enables the kernel to use EFI runtime services that are
1935 available (such as the EFI variable services).
1936
1937 This option is only useful on systems that have EFI firmware.
1938 In addition, you should use the latest ELILO loader available
1939 at <http://elilo.sourceforge.net> in order to take advantage
1940 of EFI runtime services. However, even with this option, the
1941 resultant kernel should continue to boot on existing non-EFI
1942 platforms.
1943
1944config EFI_STUB
1945 bool "EFI stub support"
1946 depends on EFI && !X86_USE_3DNOW
1947 select RELOCATABLE
1948 ---help---
1949 This kernel feature allows a bzImage to be loaded directly
1950 by EFI firmware without the use of a bootloader.
1951
1952 See Documentation/efi-stub.txt for more information.
1953
1954config EFI_MIXED
1955 bool "EFI mixed-mode support"
1956 depends on EFI_STUB && X86_64
1957 ---help---
1958 Enabling this feature allows a 64-bit kernel to be booted
1959 on a 32-bit firmware, provided that your CPU supports 64-bit
1960 mode.
1961
1962 Note that it is not possible to boot a mixed-mode enabled
1963 kernel via the EFI boot stub - a bootloader that supports
1964 the EFI handover protocol must be used.
1965
1966 If unsure, say N.
1967
1968config SECCOMP
1969 def_bool y
1970 prompt "Enable seccomp to safely compute untrusted bytecode"
1971 ---help---
1972 This kernel feature is useful for number crunching applications
1973 that may need to compute untrusted bytecode during their
1974 execution. By using pipes or other transports made available to
1975 the process as file descriptors supporting the read/write
1976 syscalls, it's possible to isolate those applications in
1977 their own address space using seccomp. Once seccomp is
1978 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1979 and the task is only allowed to execute a few safe syscalls
1980 defined by each seccomp mode.
1981
1982 If unsure, say Y. Only embedded should say N here.
1983
1984source kernel/Kconfig.hz
1985
1986config KEXEC
1987 bool "kexec system call"
1988 select KEXEC_CORE
1989 ---help---
1990 kexec is a system call that implements the ability to shutdown your
1991 current kernel, and to start another kernel. It is like a reboot
1992 but it is independent of the system firmware. And like a reboot
1993 you can start any kernel with it, not just Linux.
1994
1995 The name comes from the similarity to the exec system call.
1996
1997 It is an ongoing process to be certain the hardware in a machine
1998 is properly shutdown, so do not be surprised if this code does not
1999 initially work for you. As of this writing the exact hardware
2000 interface is strongly in flux, so no good recommendation can be
2001 made.
2002
2003config KEXEC_FILE
2004 bool "kexec file based system call"
2005 select KEXEC_CORE
2006 select BUILD_BIN2C
2007 depends on X86_64
2008 depends on CRYPTO=y
2009 depends on CRYPTO_SHA256=y
2010 ---help---
2011 This is new version of kexec system call. This system call is
2012 file based and takes file descriptors as system call argument
2013 for kernel and initramfs as opposed to list of segments as
2014 accepted by previous system call.
2015
2016config ARCH_HAS_KEXEC_PURGATORY
2017 def_bool KEXEC_FILE
2018
2019config KEXEC_VERIFY_SIG
2020 bool "Verify kernel signature during kexec_file_load() syscall"
2021 depends on KEXEC_FILE
2022 ---help---
2023 This option makes kernel signature verification mandatory for
2024 the kexec_file_load() syscall.
2025
2026 In addition to that option, you need to enable signature
2027 verification for the corresponding kernel image type being
2028 loaded in order for this to work.
2029
2030config KEXEC_BZIMAGE_VERIFY_SIG
2031 bool "Enable bzImage signature verification support"
2032 depends on KEXEC_VERIFY_SIG
2033 depends on SIGNED_PE_FILE_VERIFICATION
2034 select SYSTEM_TRUSTED_KEYRING
2035 ---help---
2036 Enable bzImage signature verification support.
2037
2038config CRASH_DUMP
2039 bool "kernel crash dumps"
2040 depends on X86_64 || (X86_32 && HIGHMEM)
2041 ---help---
2042 Generate crash dump after being started by kexec.
2043 This should be normally only set in special crash dump kernels
2044 which are loaded in the main kernel with kexec-tools into
2045 a specially reserved region and then later executed after
2046 a crash by kdump/kexec. The crash dump kernel must be compiled
2047 to a memory address not used by the main kernel or BIOS using
2048 PHYSICAL_START, or it must be built as a relocatable image
2049 (CONFIG_RELOCATABLE=y).
2050 For more details see Documentation/kdump/kdump.txt
2051
2052config KEXEC_JUMP
2053 bool "kexec jump"
2054 depends on KEXEC && HIBERNATION
2055 ---help---
2056 Jump between original kernel and kexeced kernel and invoke
2057 code in physical address mode via KEXEC
2058
2059config PHYSICAL_START
2060 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2061 default "0x1000000"
2062 ---help---
2063 This gives the physical address where the kernel is loaded.
2064
2065 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2066 bzImage will decompress itself to above physical address and
2067 run from there. Otherwise, bzImage will run from the address where
2068 it has been loaded by the boot loader and will ignore above physical
2069 address.
2070
2071 In normal kdump cases one does not have to set/change this option
2072 as now bzImage can be compiled as a completely relocatable image
2073 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2074 address. This option is mainly useful for the folks who don't want
2075 to use a bzImage for capturing the crash dump and want to use a
2076 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2077 to be specifically compiled to run from a specific memory area
2078 (normally a reserved region) and this option comes handy.
2079
2080 So if you are using bzImage for capturing the crash dump,
2081 leave the value here unchanged to 0x1000000 and set
2082 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2083 for capturing the crash dump change this value to start of
2084 the reserved region. In other words, it can be set based on
2085 the "X" value as specified in the "crashkernel=YM@XM"
2086 command line boot parameter passed to the panic-ed
2087 kernel. Please take a look at Documentation/kdump/kdump.txt
2088 for more details about crash dumps.
2089
2090 Usage of bzImage for capturing the crash dump is recommended as
2091 one does not have to build two kernels. Same kernel can be used
2092 as production kernel and capture kernel. Above option should have
2093 gone away after relocatable bzImage support is introduced. But it
2094 is present because there are users out there who continue to use
2095 vmlinux for dump capture. This option should go away down the
2096 line.
2097
2098 Don't change this unless you know what you are doing.
2099
2100config RELOCATABLE
2101 bool "Build a relocatable kernel"
2102 default y
2103 ---help---
2104 This builds a kernel image that retains relocation information
2105 so it can be loaded someplace besides the default 1MB.
2106 The relocations tend to make the kernel binary about 10% larger,
2107 but are discarded at runtime.
2108
2109 One use is for the kexec on panic case where the recovery kernel
2110 must live at a different physical address than the primary
2111 kernel.
2112
2113 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2114 it has been loaded at and the compile time physical address
2115 (CONFIG_PHYSICAL_START) is used as the minimum location.
2116
2117config RANDOMIZE_BASE
2118 bool "Randomize the address of the kernel image (KASLR)"
2119 depends on RELOCATABLE
2120 default y
2121 ---help---
2122 In support of Kernel Address Space Layout Randomization (KASLR),
2123 this randomizes the physical address at which the kernel image
2124 is decompressed and the virtual address where the kernel
2125 image is mapped, as a security feature that deters exploit
2126 attempts relying on knowledge of the location of kernel
2127 code internals.
2128
2129 On 64-bit, the kernel physical and virtual addresses are
2130 randomized separately. The physical address will be anywhere
2131 between 16MB and the top of physical memory (up to 64TB). The
2132 virtual address will be randomized from 16MB up to 1GB (9 bits
2133 of entropy). Note that this also reduces the memory space
2134 available to kernel modules from 1.5GB to 1GB.
2135
2136 On 32-bit, the kernel physical and virtual addresses are
2137 randomized together. They will be randomized from 16MB up to
2138 512MB (8 bits of entropy).
2139
2140 Entropy is generated using the RDRAND instruction if it is
2141 supported. If RDTSC is supported, its value is mixed into
2142 the entropy pool as well. If neither RDRAND nor RDTSC are
2143 supported, then entropy is read from the i8254 timer. The
2144 usable entropy is limited by the kernel being built using
2145 2GB addressing, and that PHYSICAL_ALIGN must be at a
2146 minimum of 2MB. As a result, only 10 bits of entropy are
2147 theoretically possible, but the implementations are further
2148 limited due to memory layouts.
2149
2150 If unsure, say Y.
2151
2152# Relocation on x86 needs some additional build support
2153config X86_NEED_RELOCS
2154 def_bool y
2155 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2156
2157config PHYSICAL_ALIGN
2158 hex "Alignment value to which kernel should be aligned"
2159 default "0x200000"
2160 range 0x2000 0x1000000 if X86_32
2161 range 0x200000 0x1000000 if X86_64
2162 ---help---
2163 This value puts the alignment restrictions on physical address
2164 where kernel is loaded and run from. Kernel is compiled for an
2165 address which meets above alignment restriction.
2166
2167 If bootloader loads the kernel at a non-aligned address and
2168 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2169 address aligned to above value and run from there.
2170
2171 If bootloader loads the kernel at a non-aligned address and
2172 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2173 load address and decompress itself to the address it has been
2174 compiled for and run from there. The address for which kernel is
2175 compiled already meets above alignment restrictions. Hence the
2176 end result is that kernel runs from a physical address meeting
2177 above alignment restrictions.
2178
2179 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2180 this value must be a multiple of 0x200000.
2181
2182 Don't change this unless you know what you are doing.
2183
2184config DYNAMIC_MEMORY_LAYOUT
2185 bool
2186 ---help---
2187 This option makes base addresses of vmalloc and vmemmap as well as
2188 __PAGE_OFFSET movable during boot.
2189
2190config RANDOMIZE_MEMORY
2191 bool "Randomize the kernel memory sections"
2192 depends on X86_64
2193 depends on RANDOMIZE_BASE
2194 select DYNAMIC_MEMORY_LAYOUT
2195 default RANDOMIZE_BASE
2196 ---help---
2197 Randomizes the base virtual address of kernel memory sections
2198 (physical memory mapping, vmalloc & vmemmap). This security feature
2199 makes exploits relying on predictable memory locations less reliable.
2200
2201 The order of allocations remains unchanged. Entropy is generated in
2202 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2203 configuration have in average 30,000 different possible virtual
2204 addresses for each memory section.
2205
2206 If unsure, say Y.
2207
2208config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2209 hex "Physical memory mapping padding" if EXPERT
2210 depends on RANDOMIZE_MEMORY
2211 default "0xa" if MEMORY_HOTPLUG
2212 default "0x0"
2213 range 0x1 0x40 if MEMORY_HOTPLUG
2214 range 0x0 0x40
2215 ---help---
2216 Define the padding in terabytes added to the existing physical
2217 memory size during kernel memory randomization. It is useful
2218 for memory hotplug support but reduces the entropy available for
2219 address randomization.
2220
2221 If unsure, leave at the default value.
2222
2223config HOTPLUG_CPU
2224 bool "Support for hot-pluggable CPUs"
2225 depends on SMP
2226 ---help---
2227 Say Y here to allow turning CPUs off and on. CPUs can be
2228 controlled through /sys/devices/system/cpu.
2229 ( Note: power management support will enable this option
2230 automatically on SMP systems. )
2231 Say N if you want to disable CPU hotplug.
2232
2233config BOOTPARAM_HOTPLUG_CPU0
2234 bool "Set default setting of cpu0_hotpluggable"
2235 default n
2236 depends on HOTPLUG_CPU
2237 ---help---
2238 Set whether default state of cpu0_hotpluggable is on or off.
2239
2240 Say Y here to enable CPU0 hotplug by default. If this switch
2241 is turned on, there is no need to give cpu0_hotplug kernel
2242 parameter and the CPU0 hotplug feature is enabled by default.
2243
2244 Please note: there are two known CPU0 dependencies if you want
2245 to enable the CPU0 hotplug feature either by this switch or by
2246 cpu0_hotplug kernel parameter.
2247
2248 First, resume from hibernate or suspend always starts from CPU0.
2249 So hibernate and suspend are prevented if CPU0 is offline.
2250
2251 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2252 offline if any interrupt can not migrate out of CPU0. There may
2253 be other CPU0 dependencies.
2254
2255 Please make sure the dependencies are under your control before
2256 you enable this feature.
2257
2258 Say N if you don't want to enable CPU0 hotplug feature by default.
2259 You still can enable the CPU0 hotplug feature at boot by kernel
2260 parameter cpu0_hotplug.
2261
2262config DEBUG_HOTPLUG_CPU0
2263 def_bool n
2264 prompt "Debug CPU0 hotplug"
2265 depends on HOTPLUG_CPU
2266 ---help---
2267 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2268 soon as possible and boots up userspace with CPU0 offlined. User
2269 can online CPU0 back after boot time.
2270
2271 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2272 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2273 compilation or giving cpu0_hotplug kernel parameter at boot.
2274
2275 If unsure, say N.
2276
2277config COMPAT_VDSO
2278 def_bool n
2279 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2280 depends on COMPAT_32
2281 ---help---
2282 Certain buggy versions of glibc will crash if they are
2283 presented with a 32-bit vDSO that is not mapped at the address
2284 indicated in its segment table.
2285
2286 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2287 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2288 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2289 the only released version with the bug, but OpenSUSE 9
2290 contains a buggy "glibc 2.3.2".
2291
2292 The symptom of the bug is that everything crashes on startup, saying:
2293 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2294
2295 Saying Y here changes the default value of the vdso32 boot
2296 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2297 This works around the glibc bug but hurts performance.
2298
2299 If unsure, say N: if you are compiling your own kernel, you
2300 are unlikely to be using a buggy version of glibc.
2301
2302choice
2303 prompt "vsyscall table for legacy applications"
2304 depends on X86_64
2305 default LEGACY_VSYSCALL_EMULATE
2306 help
2307 Legacy user code that does not know how to find the vDSO expects
2308 to be able to issue three syscalls by calling fixed addresses in
2309 kernel space. Since this location is not randomized with ASLR,
2310 it can be used to assist security vulnerability exploitation.
2311
2312 This setting can be changed at boot time via the kernel command
2313 line parameter vsyscall=[emulate|none].
2314
2315 On a system with recent enough glibc (2.14 or newer) and no
2316 static binaries, you can say None without a performance penalty
2317 to improve security.
2318
2319 If unsure, select "Emulate".
2320
2321 config LEGACY_VSYSCALL_EMULATE
2322 bool "Emulate"
2323 help
2324 The kernel traps and emulates calls into the fixed
2325 vsyscall address mapping. This makes the mapping
2326 non-executable, but it still contains known contents,
2327 which could be used in certain rare security vulnerability
2328 exploits. This configuration is recommended when userspace
2329 still uses the vsyscall area.
2330
2331 config LEGACY_VSYSCALL_NONE
2332 bool "None"
2333 help
2334 There will be no vsyscall mapping at all. This will
2335 eliminate any risk of ASLR bypass due to the vsyscall
2336 fixed address mapping. Attempts to use the vsyscalls
2337 will be reported to dmesg, so that either old or
2338 malicious userspace programs can be identified.
2339
2340endchoice
2341
2342config CMDLINE_BOOL
2343 bool "Built-in kernel command line"
2344 ---help---
2345 Allow for specifying boot arguments to the kernel at
2346 build time. On some systems (e.g. embedded ones), it is
2347 necessary or convenient to provide some or all of the
2348 kernel boot arguments with the kernel itself (that is,
2349 to not rely on the boot loader to provide them.)
2350
2351 To compile command line arguments into the kernel,
2352 set this option to 'Y', then fill in the
2353 boot arguments in CONFIG_CMDLINE.
2354
2355 Systems with fully functional boot loaders (i.e. non-embedded)
2356 should leave this option set to 'N'.
2357
2358config CMDLINE
2359 string "Built-in kernel command string"
2360 depends on CMDLINE_BOOL
2361 default ""
2362 ---help---
2363 Enter arguments here that should be compiled into the kernel
2364 image and used at boot time. If the boot loader provides a
2365 command line at boot time, it is appended to this string to
2366 form the full kernel command line, when the system boots.
2367
2368 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2369 change this behavior.
2370
2371 In most cases, the command line (whether built-in or provided
2372 by the boot loader) should specify the device for the root
2373 file system.
2374
2375config CMDLINE_OVERRIDE
2376 bool "Built-in command line overrides boot loader arguments"
2377 depends on CMDLINE_BOOL
2378 ---help---
2379 Set this option to 'Y' to have the kernel ignore the boot loader
2380 command line, and use ONLY the built-in command line.
2381
2382 This is used to work around broken boot loaders. This should
2383 be set to 'N' under normal conditions.
2384
2385config MODIFY_LDT_SYSCALL
2386 bool "Enable the LDT (local descriptor table)" if EXPERT
2387 default y
2388 ---help---
2389 Linux can allow user programs to install a per-process x86
2390 Local Descriptor Table (LDT) using the modify_ldt(2) system
2391 call. This is required to run 16-bit or segmented code such as
2392 DOSEMU or some Wine programs. It is also used by some very old
2393 threading libraries.
2394
2395 Enabling this feature adds a small amount of overhead to
2396 context switches and increases the low-level kernel attack
2397 surface. Disabling it removes the modify_ldt(2) system call.
2398
2399 Saying 'N' here may make sense for embedded or server kernels.
2400
2401source "kernel/livepatch/Kconfig"
2402
2403endmenu
2404
2405config ARCH_HAS_ADD_PAGES
2406 def_bool y
2407 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2408
2409config ARCH_ENABLE_MEMORY_HOTPLUG
2410 def_bool y
2411 depends on X86_64 || (X86_32 && HIGHMEM)
2412
2413config ARCH_ENABLE_MEMORY_HOTREMOVE
2414 def_bool y
2415 depends on MEMORY_HOTPLUG
2416
2417config USE_PERCPU_NUMA_NODE_ID
2418 def_bool y
2419 depends on NUMA
2420
2421config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2422 def_bool y
2423 depends on X86_64 || X86_PAE
2424
2425config ARCH_ENABLE_HUGEPAGE_MIGRATION
2426 def_bool y
2427 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2428
2429config ARCH_ENABLE_THP_MIGRATION
2430 def_bool y
2431 depends on X86_64 && TRANSPARENT_HUGEPAGE
2432
2433menu "Power management and ACPI options"
2434
2435config ARCH_HIBERNATION_HEADER
2436 def_bool y
2437 depends on X86_64 && HIBERNATION
2438
2439source "kernel/power/Kconfig"
2440
2441source "drivers/acpi/Kconfig"
2442
2443source "drivers/sfi/Kconfig"
2444
2445config X86_APM_BOOT
2446 def_bool y
2447 depends on APM
2448
2449menuconfig APM
2450 tristate "APM (Advanced Power Management) BIOS support"
2451 depends on X86_32 && PM_SLEEP
2452 ---help---
2453 APM is a BIOS specification for saving power using several different
2454 techniques. This is mostly useful for battery powered laptops with
2455 APM compliant BIOSes. If you say Y here, the system time will be
2456 reset after a RESUME operation, the /proc/apm device will provide
2457 battery status information, and user-space programs will receive
2458 notification of APM "events" (e.g. battery status change).
2459
2460 If you select "Y" here, you can disable actual use of the APM
2461 BIOS by passing the "apm=off" option to the kernel at boot time.
2462
2463 Note that the APM support is almost completely disabled for
2464 machines with more than one CPU.
2465
2466 In order to use APM, you will need supporting software. For location
2467 and more information, read <file:Documentation/power/apm-acpi.txt>
2468 and the Battery Powered Linux mini-HOWTO, available from
2469 <http://www.tldp.org/docs.html#howto>.
2470
2471 This driver does not spin down disk drives (see the hdparm(8)
2472 manpage ("man 8 hdparm") for that), and it doesn't turn off
2473 VESA-compliant "green" monitors.
2474
2475 This driver does not support the TI 4000M TravelMate and the ACER
2476 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2477 desktop machines also don't have compliant BIOSes, and this driver
2478 may cause those machines to panic during the boot phase.
2479
2480 Generally, if you don't have a battery in your machine, there isn't
2481 much point in using this driver and you should say N. If you get
2482 random kernel OOPSes or reboots that don't seem to be related to
2483 anything, try disabling/enabling this option (or disabling/enabling
2484 APM in your BIOS).
2485
2486 Some other things you should try when experiencing seemingly random,
2487 "weird" problems:
2488
2489 1) make sure that you have enough swap space and that it is
2490 enabled.
2491 2) pass the "no-hlt" option to the kernel
2492 3) switch on floating point emulation in the kernel and pass
2493 the "no387" option to the kernel
2494 4) pass the "floppy=nodma" option to the kernel
2495 5) pass the "mem=4M" option to the kernel (thereby disabling
2496 all but the first 4 MB of RAM)
2497 6) make sure that the CPU is not over clocked.
2498 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2499 8) disable the cache from your BIOS settings
2500 9) install a fan for the video card or exchange video RAM
2501 10) install a better fan for the CPU
2502 11) exchange RAM chips
2503 12) exchange the motherboard.
2504
2505 To compile this driver as a module, choose M here: the
2506 module will be called apm.
2507
2508if APM
2509
2510config APM_IGNORE_USER_SUSPEND
2511 bool "Ignore USER SUSPEND"
2512 ---help---
2513 This option will ignore USER SUSPEND requests. On machines with a
2514 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2515 series notebooks, it is necessary to say Y because of a BIOS bug.
2516
2517config APM_DO_ENABLE
2518 bool "Enable PM at boot time"
2519 ---help---
2520 Enable APM features at boot time. From page 36 of the APM BIOS
2521 specification: "When disabled, the APM BIOS does not automatically
2522 power manage devices, enter the Standby State, enter the Suspend
2523 State, or take power saving steps in response to CPU Idle calls."
2524 This driver will make CPU Idle calls when Linux is idle (unless this
2525 feature is turned off -- see "Do CPU IDLE calls", below). This
2526 should always save battery power, but more complicated APM features
2527 will be dependent on your BIOS implementation. You may need to turn
2528 this option off if your computer hangs at boot time when using APM
2529 support, or if it beeps continuously instead of suspending. Turn
2530 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2531 T400CDT. This is off by default since most machines do fine without
2532 this feature.
2533
2534config APM_CPU_IDLE
2535 depends on CPU_IDLE
2536 bool "Make CPU Idle calls when idle"
2537 ---help---
2538 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2539 On some machines, this can activate improved power savings, such as
2540 a slowed CPU clock rate, when the machine is idle. These idle calls
2541 are made after the idle loop has run for some length of time (e.g.,
2542 333 mS). On some machines, this will cause a hang at boot time or
2543 whenever the CPU becomes idle. (On machines with more than one CPU,
2544 this option does nothing.)
2545
2546config APM_DISPLAY_BLANK
2547 bool "Enable console blanking using APM"
2548 ---help---
2549 Enable console blanking using the APM. Some laptops can use this to
2550 turn off the LCD backlight when the screen blanker of the Linux
2551 virtual console blanks the screen. Note that this is only used by
2552 the virtual console screen blanker, and won't turn off the backlight
2553 when using the X Window system. This also doesn't have anything to
2554 do with your VESA-compliant power-saving monitor. Further, this
2555 option doesn't work for all laptops -- it might not turn off your
2556 backlight at all, or it might print a lot of errors to the console,
2557 especially if you are using gpm.
2558
2559config APM_ALLOW_INTS
2560 bool "Allow interrupts during APM BIOS calls"
2561 ---help---
2562 Normally we disable external interrupts while we are making calls to
2563 the APM BIOS as a measure to lessen the effects of a badly behaving
2564 BIOS implementation. The BIOS should reenable interrupts if it
2565 needs to. Unfortunately, some BIOSes do not -- especially those in
2566 many of the newer IBM Thinkpads. If you experience hangs when you
2567 suspend, try setting this to Y. Otherwise, say N.
2568
2569endif # APM
2570
2571source "drivers/cpufreq/Kconfig"
2572
2573source "drivers/cpuidle/Kconfig"
2574
2575source "drivers/idle/Kconfig"
2576
2577endmenu
2578
2579
2580menu "Bus options (PCI etc.)"
2581
2582config PCI
2583 bool "PCI support"
2584 default y
2585 ---help---
2586 Find out whether you have a PCI motherboard. PCI is the name of a
2587 bus system, i.e. the way the CPU talks to the other stuff inside
2588 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2589 VESA. If you have PCI, say Y, otherwise N.
2590
2591choice
2592 prompt "PCI access mode"
2593 depends on X86_32 && PCI
2594 default PCI_GOANY
2595 ---help---
2596 On PCI systems, the BIOS can be used to detect the PCI devices and
2597 determine their configuration. However, some old PCI motherboards
2598 have BIOS bugs and may crash if this is done. Also, some embedded
2599 PCI-based systems don't have any BIOS at all. Linux can also try to
2600 detect the PCI hardware directly without using the BIOS.
2601
2602 With this option, you can specify how Linux should detect the
2603 PCI devices. If you choose "BIOS", the BIOS will be used,
2604 if you choose "Direct", the BIOS won't be used, and if you
2605 choose "MMConfig", then PCI Express MMCONFIG will be used.
2606 If you choose "Any", the kernel will try MMCONFIG, then the
2607 direct access method and falls back to the BIOS if that doesn't
2608 work. If unsure, go with the default, which is "Any".
2609
2610config PCI_GOBIOS
2611 bool "BIOS"
2612
2613config PCI_GOMMCONFIG
2614 bool "MMConfig"
2615
2616config PCI_GODIRECT
2617 bool "Direct"
2618
2619config PCI_GOOLPC
2620 bool "OLPC XO-1"
2621 depends on OLPC
2622
2623config PCI_GOANY
2624 bool "Any"
2625
2626endchoice
2627
2628config PCI_BIOS
2629 def_bool y
2630 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2631
2632# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2633config PCI_DIRECT
2634 def_bool y
2635 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2636
2637config PCI_MMCONFIG
2638 bool "Support mmconfig PCI config space access" if X86_64
2639 default y
2640 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2641 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2642
2643config PCI_OLPC
2644 def_bool y
2645 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2646
2647config PCI_XEN
2648 def_bool y
2649 depends on PCI && XEN
2650 select SWIOTLB_XEN
2651
2652config PCI_DOMAINS
2653 def_bool y
2654 depends on PCI
2655
2656config MMCONF_FAM10H
2657 def_bool y
2658 depends on X86_64 && PCI_MMCONFIG && ACPI
2659
2660config PCI_CNB20LE_QUIRK
2661 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2662 depends on PCI
2663 help
2664 Read the PCI windows out of the CNB20LE host bridge. This allows
2665 PCI hotplug to work on systems with the CNB20LE chipset which do
2666 not have ACPI.
2667
2668 There's no public spec for this chipset, and this functionality
2669 is known to be incomplete.
2670
2671 You should say N unless you know you need this.
2672
2673source "drivers/pci/Kconfig"
2674
2675config ISA_BUS
2676 bool "ISA bus support on modern systems" if EXPERT
2677 help
2678 Expose ISA bus device drivers and options available for selection and
2679 configuration. Enable this option if your target machine has an ISA
2680 bus. ISA is an older system, displaced by PCI and newer bus
2681 architectures -- if your target machine is modern, it probably does
2682 not have an ISA bus.
2683
2684 If unsure, say N.
2685
2686# x86_64 have no ISA slots, but can have ISA-style DMA.
2687config ISA_DMA_API
2688 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2689 default y
2690 help
2691 Enables ISA-style DMA support for devices requiring such controllers.
2692 If unsure, say Y.
2693
2694if X86_32
2695
2696config ISA
2697 bool "ISA support"
2698 ---help---
2699 Find out whether you have ISA slots on your motherboard. ISA is the
2700 name of a bus system, i.e. the way the CPU talks to the other stuff
2701 inside your box. Other bus systems are PCI, EISA, MicroChannel
2702 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2703 newer boards don't support it. If you have ISA, say Y, otherwise N.
2704
2705config EISA
2706 bool "EISA support"
2707 depends on ISA
2708 ---help---
2709 The Extended Industry Standard Architecture (EISA) bus was
2710 developed as an open alternative to the IBM MicroChannel bus.
2711
2712 The EISA bus provided some of the features of the IBM MicroChannel
2713 bus while maintaining backward compatibility with cards made for
2714 the older ISA bus. The EISA bus saw limited use between 1988 and
2715 1995 when it was made obsolete by the PCI bus.
2716
2717 Say Y here if you are building a kernel for an EISA-based machine.
2718
2719 Otherwise, say N.
2720
2721source "drivers/eisa/Kconfig"
2722
2723config SCx200
2724 tristate "NatSemi SCx200 support"
2725 ---help---
2726 This provides basic support for National Semiconductor's
2727 (now AMD's) Geode processors. The driver probes for the
2728 PCI-IDs of several on-chip devices, so its a good dependency
2729 for other scx200_* drivers.
2730
2731 If compiled as a module, the driver is named scx200.
2732
2733config SCx200HR_TIMER
2734 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2735 depends on SCx200
2736 default y
2737 ---help---
2738 This driver provides a clocksource built upon the on-chip
2739 27MHz high-resolution timer. Its also a workaround for
2740 NSC Geode SC-1100's buggy TSC, which loses time when the
2741 processor goes idle (as is done by the scheduler). The
2742 other workaround is idle=poll boot option.
2743
2744config OLPC
2745 bool "One Laptop Per Child support"
2746 depends on !X86_PAE
2747 select GPIOLIB
2748 select OF
2749 select OF_PROMTREE
2750 select IRQ_DOMAIN
2751 ---help---
2752 Add support for detecting the unique features of the OLPC
2753 XO hardware.
2754
2755config OLPC_XO1_PM
2756 bool "OLPC XO-1 Power Management"
2757 depends on OLPC && MFD_CS5535 && PM_SLEEP
2758 select MFD_CORE
2759 ---help---
2760 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2761
2762config OLPC_XO1_RTC
2763 bool "OLPC XO-1 Real Time Clock"
2764 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2765 ---help---
2766 Add support for the XO-1 real time clock, which can be used as a
2767 programmable wakeup source.
2768
2769config OLPC_XO1_SCI
2770 bool "OLPC XO-1 SCI extras"
2771 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2772 depends on INPUT=y
2773 select POWER_SUPPLY
2774 ---help---
2775 Add support for SCI-based features of the OLPC XO-1 laptop:
2776 - EC-driven system wakeups
2777 - Power button
2778 - Ebook switch
2779 - Lid switch
2780 - AC adapter status updates
2781 - Battery status updates
2782
2783config OLPC_XO15_SCI
2784 bool "OLPC XO-1.5 SCI extras"
2785 depends on OLPC && ACPI
2786 select POWER_SUPPLY
2787 ---help---
2788 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2789 - EC-driven system wakeups
2790 - AC adapter status updates
2791 - Battery status updates
2792
2793config ALIX
2794 bool "PCEngines ALIX System Support (LED setup)"
2795 select GPIOLIB
2796 ---help---
2797 This option enables system support for the PCEngines ALIX.
2798 At present this just sets up LEDs for GPIO control on
2799 ALIX2/3/6 boards. However, other system specific setup should
2800 get added here.
2801
2802 Note: You must still enable the drivers for GPIO and LED support
2803 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2804
2805 Note: You have to set alix.force=1 for boards with Award BIOS.
2806
2807config NET5501
2808 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2809 select GPIOLIB
2810 ---help---
2811 This option enables system support for the Soekris Engineering net5501.
2812
2813config GEOS
2814 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2815 select GPIOLIB
2816 depends on DMI
2817 ---help---
2818 This option enables system support for the Traverse Technologies GEOS.
2819
2820config TS5500
2821 bool "Technologic Systems TS-5500 platform support"
2822 depends on MELAN
2823 select CHECK_SIGNATURE
2824 select NEW_LEDS
2825 select LEDS_CLASS
2826 ---help---
2827 This option enables system support for the Technologic Systems TS-5500.
2828
2829endif # X86_32
2830
2831config AMD_NB
2832 def_bool y
2833 depends on CPU_SUP_AMD && PCI
2834
2835source "drivers/pcmcia/Kconfig"
2836
2837config RAPIDIO
2838 tristate "RapidIO support"
2839 depends on PCI
2840 default n
2841 help
2842 If enabled this option will include drivers and the core
2843 infrastructure code to support RapidIO interconnect devices.
2844
2845source "drivers/rapidio/Kconfig"
2846
2847config X86_SYSFB
2848 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2849 help
2850 Firmwares often provide initial graphics framebuffers so the BIOS,
2851 bootloader or kernel can show basic video-output during boot for
2852 user-guidance and debugging. Historically, x86 used the VESA BIOS
2853 Extensions and EFI-framebuffers for this, which are mostly limited
2854 to x86.
2855 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2856 framebuffers so the new generic system-framebuffer drivers can be
2857 used on x86. If the framebuffer is not compatible with the generic
2858 modes, it is adverticed as fallback platform framebuffer so legacy
2859 drivers like efifb, vesafb and uvesafb can pick it up.
2860 If this option is not selected, all system framebuffers are always
2861 marked as fallback platform framebuffers as usual.
2862
2863 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2864 not be able to pick up generic system framebuffers if this option
2865 is selected. You are highly encouraged to enable simplefb as
2866 replacement if you select this option. simplefb can correctly deal
2867 with generic system framebuffers. But you should still keep vesafb
2868 and others enabled as fallback if a system framebuffer is
2869 incompatible with simplefb.
2870
2871 If unsure, say Y.
2872
2873endmenu
2874
2875
2876menu "Executable file formats / Emulations"
2877
2878source "fs/Kconfig.binfmt"
2879
2880config IA32_EMULATION
2881 bool "IA32 Emulation"
2882 depends on X86_64
2883 select ARCH_WANT_OLD_COMPAT_IPC
2884 select BINFMT_ELF
2885 select COMPAT_BINFMT_ELF
2886 select COMPAT_OLD_SIGACTION
2887 ---help---
2888 Include code to run legacy 32-bit programs under a
2889 64-bit kernel. You should likely turn this on, unless you're
2890 100% sure that you don't have any 32-bit programs left.
2891
2892config IA32_AOUT
2893 tristate "IA32 a.out support"
2894 depends on IA32_EMULATION
2895 ---help---
2896 Support old a.out binaries in the 32bit emulation.
2897
2898config X86_X32
2899 bool "x32 ABI for 64-bit mode"
2900 depends on X86_64
2901 ---help---
2902 Include code to run binaries for the x32 native 32-bit ABI
2903 for 64-bit processors. An x32 process gets access to the
2904 full 64-bit register file and wide data path while leaving
2905 pointers at 32 bits for smaller memory footprint.
2906
2907 You will need a recent binutils (2.22 or later) with
2908 elf32_x86_64 support enabled to compile a kernel with this
2909 option set.
2910
2911config COMPAT_32
2912 def_bool y
2913 depends on IA32_EMULATION || X86_32
2914 select HAVE_UID16
2915 select OLD_SIGSUSPEND3
2916
2917config COMPAT
2918 def_bool y
2919 depends on IA32_EMULATION || X86_X32
2920
2921if COMPAT
2922config COMPAT_FOR_U64_ALIGNMENT
2923 def_bool y
2924
2925config SYSVIPC_COMPAT
2926 def_bool y
2927 depends on SYSVIPC
2928endif
2929
2930endmenu
2931
2932
2933config HAVE_ATOMIC_IOMAP
2934 def_bool y
2935 depends on X86_32
2936
2937config X86_DEV_DMA_OPS
2938 bool
2939 depends on X86_64 || STA2X11
2940
2941config X86_DMA_REMAP
2942 bool
2943 depends on STA2X11
2944
2945config HAVE_GENERIC_GUP
2946 def_bool y
2947
2948source "net/Kconfig"
2949
2950source "drivers/Kconfig"
2951
2952source "drivers/firmware/Kconfig"
2953
2954source "fs/Kconfig"
2955
2956source "arch/x86/Kconfig.debug"
2957
2958source "security/Kconfig"
2959
2960source "crypto/Kconfig"
2961
2962source "arch/x86/kvm/Kconfig"
2963
2964source "lib/Kconfig"