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 MODULES_USE_ELF_REL
18 select OLD_SIGACTION
19
20config X86_64
21 def_bool y
22 depends on 64BIT
23 # Options that are inherently 64-bit kernel only:
24 select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
25 select ARCH_SUPPORTS_INT128
26 select ARCH_USE_CMPXCHG_LOCKREF
27 select HAVE_ARCH_SOFT_DIRTY
28 select MODULES_USE_ELF_RELA
29 select NEED_DMA_MAP_STATE
30 select SWIOTLB
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_32BIT_OFF_T if X86_32
49 select ARCH_CLOCKSOURCE_DATA
50 select ARCH_CLOCKSOURCE_INIT
51 select ARCH_DISCARD_MEMBLOCK
52 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
53 select ARCH_HAS_DEBUG_VIRTUAL
54 select ARCH_HAS_DEVMEM_IS_ALLOWED
55 select ARCH_HAS_ELF_RANDOMIZE
56 select ARCH_HAS_FAST_MULTIPLIER
57 select ARCH_HAS_FILTER_PGPROT
58 select ARCH_HAS_FORTIFY_SOURCE
59 select ARCH_HAS_GCOV_PROFILE_ALL
60 select ARCH_HAS_KCOV if X86_64
61 select ARCH_HAS_MEMBARRIER_SYNC_CORE
62 select ARCH_HAS_PMEM_API if X86_64
63 select ARCH_HAS_PTE_SPECIAL
64 select ARCH_HAS_REFCOUNT
65 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
66 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
67 select ARCH_HAS_SET_MEMORY
68 select ARCH_HAS_STRICT_KERNEL_RWX
69 select ARCH_HAS_STRICT_MODULE_RWX
70 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
71 select ARCH_HAS_UBSAN_SANITIZE_ALL
72 select ARCH_HAS_ZONE_DEVICE if X86_64
73 select ARCH_HAVE_NMI_SAFE_CMPXCHG
74 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
75 select ARCH_MIGHT_HAVE_PC_PARPORT
76 select ARCH_MIGHT_HAVE_PC_SERIO
77 select ARCH_SUPPORTS_ACPI
78 select ARCH_SUPPORTS_ATOMIC_RMW
79 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
80 select ARCH_USE_BUILTIN_BSWAP
81 select ARCH_USE_QUEUED_RWLOCKS
82 select ARCH_USE_QUEUED_SPINLOCKS
83 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
84 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
85 select ARCH_WANTS_THP_SWAP if X86_64
86 select BUILDTIME_EXTABLE_SORT
87 select CLKEVT_I8253
88 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
89 select CLOCKSOURCE_WATCHDOG
90 select DCACHE_WORD_ACCESS
91 select EDAC_ATOMIC_SCRUB
92 select EDAC_SUPPORT
93 select GENERIC_CLOCKEVENTS
94 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
95 select GENERIC_CLOCKEVENTS_MIN_ADJUST
96 select GENERIC_CMOS_UPDATE
97 select GENERIC_CPU_AUTOPROBE
98 select GENERIC_CPU_VULNERABILITIES
99 select GENERIC_EARLY_IOREMAP
100 select GENERIC_FIND_FIRST_BIT
101 select GENERIC_IOMAP
102 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
103 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
104 select GENERIC_IRQ_MIGRATION if SMP
105 select GENERIC_IRQ_PROBE
106 select GENERIC_IRQ_RESERVATION_MODE
107 select GENERIC_IRQ_SHOW
108 select GENERIC_PENDING_IRQ if SMP
109 select GENERIC_SMP_IDLE_THREAD
110 select GENERIC_STRNCPY_FROM_USER
111 select GENERIC_STRNLEN_USER
112 select GENERIC_TIME_VSYSCALL
113 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
114 select HAVE_ACPI_APEI if ACPI
115 select HAVE_ACPI_APEI_NMI if ACPI
116 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
117 select HAVE_ARCH_AUDITSYSCALL
118 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
119 select HAVE_ARCH_JUMP_LABEL
120 select HAVE_ARCH_JUMP_LABEL_RELATIVE
121 select HAVE_ARCH_KASAN if X86_64
122 select HAVE_ARCH_KGDB
123 select HAVE_ARCH_MMAP_RND_BITS if MMU
124 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
125 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
126 select HAVE_ARCH_PREL32_RELOCATIONS
127 select HAVE_ARCH_SECCOMP_FILTER
128 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
129 select HAVE_ARCH_STACKLEAK
130 select HAVE_ARCH_TRACEHOOK
131 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
132 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
133 select HAVE_ARCH_VMAP_STACK if X86_64
134 select HAVE_ARCH_WITHIN_STACK_FRAMES
135 select HAVE_CMPXCHG_DOUBLE
136 select HAVE_CMPXCHG_LOCAL
137 select HAVE_CONTEXT_TRACKING if X86_64
138 select HAVE_COPY_THREAD_TLS
139 select HAVE_C_RECORDMCOUNT
140 select HAVE_DEBUG_KMEMLEAK
141 select HAVE_DEBUG_STACKOVERFLOW
142 select HAVE_DMA_CONTIGUOUS
143 select HAVE_DYNAMIC_FTRACE
144 select HAVE_DYNAMIC_FTRACE_WITH_REGS
145 select HAVE_EBPF_JIT
146 select HAVE_EFFICIENT_UNALIGNED_ACCESS
147 select HAVE_EISA
148 select HAVE_EXIT_THREAD
149 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
150 select HAVE_FTRACE_MCOUNT_RECORD
151 select HAVE_FUNCTION_GRAPH_TRACER
152 select HAVE_FUNCTION_TRACER
153 select HAVE_GCC_PLUGINS
154 select HAVE_HW_BREAKPOINT
155 select HAVE_IDE
156 select HAVE_IOREMAP_PROT
157 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
158 select HAVE_IRQ_TIME_ACCOUNTING
159 select HAVE_KERNEL_BZIP2
160 select HAVE_KERNEL_GZIP
161 select HAVE_KERNEL_LZ4
162 select HAVE_KERNEL_LZMA
163 select HAVE_KERNEL_LZO
164 select HAVE_KERNEL_XZ
165 select HAVE_KPROBES
166 select HAVE_KPROBES_ON_FTRACE
167 select HAVE_FUNCTION_ERROR_INJECTION
168 select HAVE_KRETPROBES
169 select HAVE_KVM
170 select HAVE_LIVEPATCH if X86_64
171 select HAVE_MEMBLOCK_NODE_MAP
172 select HAVE_MIXED_BREAKPOINTS_REGS
173 select HAVE_MOD_ARCH_SPECIFIC
174 select HAVE_MOVE_PMD
175 select HAVE_NMI
176 select HAVE_OPROFILE
177 select HAVE_OPTPROBES
178 select HAVE_PCSPKR_PLATFORM
179 select HAVE_PERF_EVENTS
180 select HAVE_PERF_EVENTS_NMI
181 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
182 select HAVE_PCI
183 select HAVE_PERF_REGS
184 select HAVE_PERF_USER_STACK_DUMP
185 select HAVE_RCU_TABLE_FREE if PARAVIRT
186 select HAVE_RCU_TABLE_INVALIDATE if HAVE_RCU_TABLE_FREE
187 select HAVE_REGS_AND_STACK_ACCESS_API
188 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
189 select HAVE_FUNCTION_ARG_ACCESS_API
190 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
191 select HAVE_STACK_VALIDATION if X86_64
192 select HAVE_RSEQ
193 select HAVE_SYSCALL_TRACEPOINTS
194 select HAVE_UNSTABLE_SCHED_CLOCK
195 select HAVE_USER_RETURN_NOTIFIER
196 select HOTPLUG_SMT if SMP
197 select IRQ_FORCED_THREADING
198 select NEED_SG_DMA_LENGTH
199 select PCI_DOMAINS if PCI
200 select PCI_LOCKLESS_CONFIG if PCI
201 select PERF_EVENTS
202 select RTC_LIB
203 select RTC_MC146818_LIB
204 select SPARSE_IRQ
205 select SRCU
206 select SYSCTL_EXCEPTION_TRACE
207 select THREAD_INFO_IN_TASK
208 select USER_STACKTRACE_SUPPORT
209 select VIRT_TO_BUS
210 select X86_FEATURE_NAMES if PROC_FS
211
212config INSTRUCTION_DECODER
213 def_bool y
214 depends on KPROBES || PERF_EVENTS || UPROBES
215
216config OUTPUT_FORMAT
217 string
218 default "elf32-i386" if X86_32
219 default "elf64-x86-64" if X86_64
220
221config ARCH_DEFCONFIG
222 string
223 default "arch/x86/configs/i386_defconfig" if X86_32
224 default "arch/x86/configs/x86_64_defconfig" if X86_64
225
226config LOCKDEP_SUPPORT
227 def_bool y
228
229config STACKTRACE_SUPPORT
230 def_bool y
231
232config MMU
233 def_bool y
234
235config ARCH_MMAP_RND_BITS_MIN
236 default 28 if 64BIT
237 default 8
238
239config ARCH_MMAP_RND_BITS_MAX
240 default 32 if 64BIT
241 default 16
242
243config ARCH_MMAP_RND_COMPAT_BITS_MIN
244 default 8
245
246config ARCH_MMAP_RND_COMPAT_BITS_MAX
247 default 16
248
249config SBUS
250 bool
251
252config GENERIC_ISA_DMA
253 def_bool y
254 depends on ISA_DMA_API
255
256config GENERIC_BUG
257 def_bool y
258 depends on BUG
259 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
260
261config GENERIC_BUG_RELATIVE_POINTERS
262 bool
263
264config GENERIC_HWEIGHT
265 def_bool y
266
267config ARCH_MAY_HAVE_PC_FDC
268 def_bool y
269 depends on ISA_DMA_API
270
271config RWSEM_XCHGADD_ALGORITHM
272 def_bool y
273
274config GENERIC_CALIBRATE_DELAY
275 def_bool y
276
277config ARCH_HAS_CPU_RELAX
278 def_bool y
279
280config ARCH_HAS_CACHE_LINE_SIZE
281 def_bool y
282
283config ARCH_HAS_FILTER_PGPROT
284 def_bool y
285
286config HAVE_SETUP_PER_CPU_AREA
287 def_bool y
288
289config NEED_PER_CPU_EMBED_FIRST_CHUNK
290 def_bool y
291
292config NEED_PER_CPU_PAGE_FIRST_CHUNK
293 def_bool y
294
295config ARCH_HIBERNATION_POSSIBLE
296 def_bool y
297
298config ARCH_SUSPEND_POSSIBLE
299 def_bool y
300
301config ARCH_WANT_HUGE_PMD_SHARE
302 def_bool y
303
304config ARCH_WANT_GENERAL_HUGETLB
305 def_bool y
306
307config ZONE_DMA32
308 def_bool y if X86_64
309
310config AUDIT_ARCH
311 def_bool y if X86_64
312
313config ARCH_SUPPORTS_OPTIMIZED_INLINING
314 def_bool y
315
316config ARCH_SUPPORTS_DEBUG_PAGEALLOC
317 def_bool y
318
319config KASAN_SHADOW_OFFSET
320 hex
321 depends on KASAN
322 default 0xdffffc0000000000
323
324config HAVE_INTEL_TXT
325 def_bool y
326 depends on INTEL_IOMMU && ACPI
327
328config X86_32_SMP
329 def_bool y
330 depends on X86_32 && SMP
331
332config X86_64_SMP
333 def_bool y
334 depends on X86_64 && SMP
335
336config X86_32_LAZY_GS
337 def_bool y
338 depends on X86_32 && !STACKPROTECTOR
339
340config ARCH_SUPPORTS_UPROBES
341 def_bool y
342
343config FIX_EARLYCON_MEM
344 def_bool y
345
346config DYNAMIC_PHYSICAL_MASK
347 bool
348
349config PGTABLE_LEVELS
350 int
351 default 5 if X86_5LEVEL
352 default 4 if X86_64
353 default 3 if X86_PAE
354 default 2
355
356config CC_HAS_SANE_STACKPROTECTOR
357 bool
358 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
359 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
360 help
361 We have to make sure stack protector is unconditionally disabled if
362 the compiler produces broken code.
363
364menu "Processor type and features"
365
366config ZONE_DMA
367 bool "DMA memory allocation support" if EXPERT
368 default y
369 help
370 DMA memory allocation support allows devices with less than 32-bit
371 addressing to allocate within the first 16MB of address space.
372 Disable if no such devices will be used.
373
374 If unsure, say Y.
375
376config SMP
377 bool "Symmetric multi-processing support"
378 ---help---
379 This enables support for systems with more than one CPU. If you have
380 a system with only one CPU, say N. If you have a system with more
381 than one CPU, say Y.
382
383 If you say N here, the kernel will run on uni- and multiprocessor
384 machines, but will use only one CPU of a multiprocessor machine. If
385 you say Y here, the kernel will run on many, but not all,
386 uniprocessor machines. On a uniprocessor machine, the kernel
387 will run faster if you say N here.
388
389 Note that if you say Y here and choose architecture "586" or
390 "Pentium" under "Processor family", the kernel will not work on 486
391 architectures. Similarly, multiprocessor kernels for the "PPro"
392 architecture may not work on all Pentium based boards.
393
394 People using multiprocessor machines who say Y here should also say
395 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
396 Management" code will be disabled if you say Y here.
397
398 See also <file:Documentation/x86/i386/IO-APIC.txt>,
399 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
400 <http://www.tldp.org/docs.html#howto>.
401
402 If you don't know what to do here, say N.
403
404config X86_FEATURE_NAMES
405 bool "Processor feature human-readable names" if EMBEDDED
406 default y
407 ---help---
408 This option compiles in a table of x86 feature bits and corresponding
409 names. This is required to support /proc/cpuinfo and a few kernel
410 messages. You can disable this to save space, at the expense of
411 making those few kernel messages show numeric feature bits instead.
412
413 If in doubt, say Y.
414
415config X86_X2APIC
416 bool "Support x2apic"
417 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
418 ---help---
419 This enables x2apic support on CPUs that have this feature.
420
421 This allows 32-bit apic IDs (so it can support very large systems),
422 and accesses the local apic via MSRs not via mmio.
423
424 If you don't know what to do here, say N.
425
426config X86_MPPARSE
427 bool "Enable MPS table" if ACPI || SFI
428 default y
429 depends on X86_LOCAL_APIC
430 ---help---
431 For old smp systems that do not have proper acpi support. Newer systems
432 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
433
434config GOLDFISH
435 def_bool y
436 depends on X86_GOLDFISH
437
438config RETPOLINE
439 bool "Avoid speculative indirect branches in kernel"
440 default y
441 select STACK_VALIDATION if HAVE_STACK_VALIDATION
442 help
443 Compile kernel with the retpoline compiler options to guard against
444 kernel-to-user data leaks by avoiding speculative indirect
445 branches. Requires a compiler with -mindirect-branch=thunk-extern
446 support for full protection. The kernel may run slower.
447
448config X86_CPU_RESCTRL
449 bool "x86 CPU resource control support"
450 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
451 select KERNFS
452 help
453 Enable x86 CPU resource control support.
454
455 Provide support for the allocation and monitoring of system resources
456 usage by the CPU.
457
458 Intel calls this Intel Resource Director Technology
459 (Intel(R) RDT). More information about RDT can be found in the
460 Intel x86 Architecture Software Developer Manual.
461
462 AMD calls this AMD Platform Quality of Service (AMD QoS).
463 More information about AMD QoS can be found in the AMD64 Technology
464 Platform Quality of Service Extensions manual.
465
466 Say N if unsure.
467
468if X86_32
469config X86_BIGSMP
470 bool "Support for big SMP systems with more than 8 CPUs"
471 depends on SMP
472 ---help---
473 This option is needed for the systems that have more than 8 CPUs
474
475config X86_EXTENDED_PLATFORM
476 bool "Support for extended (non-PC) x86 platforms"
477 default y
478 ---help---
479 If you disable this option then the kernel will only support
480 standard PC platforms. (which covers the vast majority of
481 systems out there.)
482
483 If you enable this option then you'll be able to select support
484 for the following (non-PC) 32 bit x86 platforms:
485 Goldfish (Android emulator)
486 AMD Elan
487 RDC R-321x SoC
488 SGI 320/540 (Visual Workstation)
489 STA2X11-based (e.g. Northville)
490 Moorestown MID devices
491
492 If you have one of these systems, or if you want to build a
493 generic distribution kernel, say Y here - otherwise say N.
494endif
495
496if X86_64
497config X86_EXTENDED_PLATFORM
498 bool "Support for extended (non-PC) x86 platforms"
499 default y
500 ---help---
501 If you disable this option then the kernel will only support
502 standard PC platforms. (which covers the vast majority of
503 systems out there.)
504
505 If you enable this option then you'll be able to select support
506 for the following (non-PC) 64 bit x86 platforms:
507 Numascale NumaChip
508 ScaleMP vSMP
509 SGI Ultraviolet
510
511 If you have one of these systems, or if you want to build a
512 generic distribution kernel, say Y here - otherwise say N.
513endif
514# This is an alphabetically sorted list of 64 bit extended platforms
515# Please maintain the alphabetic order if and when there are additions
516config X86_NUMACHIP
517 bool "Numascale NumaChip"
518 depends on X86_64
519 depends on X86_EXTENDED_PLATFORM
520 depends on NUMA
521 depends on SMP
522 depends on X86_X2APIC
523 depends on PCI_MMCONFIG
524 ---help---
525 Adds support for Numascale NumaChip large-SMP systems. Needed to
526 enable more than ~168 cores.
527 If you don't have one of these, you should say N here.
528
529config X86_VSMP
530 bool "ScaleMP vSMP"
531 select HYPERVISOR_GUEST
532 select PARAVIRT
533 depends on X86_64 && PCI
534 depends on X86_EXTENDED_PLATFORM
535 depends on SMP
536 ---help---
537 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
538 supposed to run on these EM64T-based machines. Only choose this option
539 if you have one of these machines.
540
541config X86_UV
542 bool "SGI Ultraviolet"
543 depends on X86_64
544 depends on X86_EXTENDED_PLATFORM
545 depends on NUMA
546 depends on EFI
547 depends on X86_X2APIC
548 depends on PCI
549 ---help---
550 This option is needed in order to support SGI Ultraviolet systems.
551 If you don't have one of these, you should say N here.
552
553# Following is an alphabetically sorted list of 32 bit extended platforms
554# Please maintain the alphabetic order if and when there are additions
555
556config X86_GOLDFISH
557 bool "Goldfish (Virtual Platform)"
558 depends on X86_EXTENDED_PLATFORM
559 ---help---
560 Enable support for the Goldfish virtual platform used primarily
561 for Android development. Unless you are building for the Android
562 Goldfish emulator say N here.
563
564config X86_INTEL_CE
565 bool "CE4100 TV platform"
566 depends on PCI
567 depends on PCI_GODIRECT
568 depends on X86_IO_APIC
569 depends on X86_32
570 depends on X86_EXTENDED_PLATFORM
571 select X86_REBOOTFIXUPS
572 select OF
573 select OF_EARLY_FLATTREE
574 ---help---
575 Select for the Intel CE media processor (CE4100) SOC.
576 This option compiles in support for the CE4100 SOC for settop
577 boxes and media devices.
578
579config X86_INTEL_MID
580 bool "Intel MID platform support"
581 depends on X86_EXTENDED_PLATFORM
582 depends on X86_PLATFORM_DEVICES
583 depends on PCI
584 depends on X86_64 || (PCI_GOANY && X86_32)
585 depends on X86_IO_APIC
586 select SFI
587 select I2C
588 select DW_APB_TIMER
589 select APB_TIMER
590 select INTEL_SCU_IPC
591 select MFD_INTEL_MSIC
592 ---help---
593 Select to build a kernel capable of supporting Intel MID (Mobile
594 Internet Device) platform systems which do not have the PCI legacy
595 interfaces. If you are building for a PC class system say N here.
596
597 Intel MID platforms are based on an Intel processor and chipset which
598 consume less power than most of the x86 derivatives.
599
600config X86_INTEL_QUARK
601 bool "Intel Quark platform support"
602 depends on X86_32
603 depends on X86_EXTENDED_PLATFORM
604 depends on X86_PLATFORM_DEVICES
605 depends on X86_TSC
606 depends on PCI
607 depends on PCI_GOANY
608 depends on X86_IO_APIC
609 select IOSF_MBI
610 select INTEL_IMR
611 select COMMON_CLK
612 ---help---
613 Select to include support for Quark X1000 SoC.
614 Say Y here if you have a Quark based system such as the Arduino
615 compatible Intel Galileo.
616
617config X86_INTEL_LPSS
618 bool "Intel Low Power Subsystem Support"
619 depends on X86 && ACPI && PCI
620 select COMMON_CLK
621 select PINCTRL
622 select IOSF_MBI
623 ---help---
624 Select to build support for Intel Low Power Subsystem such as
625 found on Intel Lynxpoint PCH. Selecting this option enables
626 things like clock tree (common clock framework) and pincontrol
627 which are needed by the LPSS peripheral drivers.
628
629config X86_AMD_PLATFORM_DEVICE
630 bool "AMD ACPI2Platform devices support"
631 depends on ACPI
632 select COMMON_CLK
633 select PINCTRL
634 ---help---
635 Select to interpret AMD specific ACPI device to platform device
636 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
637 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
638 implemented under PINCTRL subsystem.
639
640config IOSF_MBI
641 tristate "Intel SoC IOSF Sideband support for SoC platforms"
642 depends on PCI
643 ---help---
644 This option enables sideband register access support for Intel SoC
645 platforms. On these platforms the IOSF sideband is used in lieu of
646 MSR's for some register accesses, mostly but not limited to thermal
647 and power. Drivers may query the availability of this device to
648 determine if they need the sideband in order to work on these
649 platforms. The sideband is available on the following SoC products.
650 This list is not meant to be exclusive.
651 - BayTrail
652 - Braswell
653 - Quark
654
655 You should say Y if you are running a kernel on one of these SoC's.
656
657config IOSF_MBI_DEBUG
658 bool "Enable IOSF sideband access through debugfs"
659 depends on IOSF_MBI && DEBUG_FS
660 ---help---
661 Select this option to expose the IOSF sideband access registers (MCR,
662 MDR, MCRX) through debugfs to write and read register information from
663 different units on the SoC. This is most useful for obtaining device
664 state information for debug and analysis. As this is a general access
665 mechanism, users of this option would have specific knowledge of the
666 device they want to access.
667
668 If you don't require the option or are in doubt, say N.
669
670config X86_RDC321X
671 bool "RDC R-321x SoC"
672 depends on X86_32
673 depends on X86_EXTENDED_PLATFORM
674 select M486
675 select X86_REBOOTFIXUPS
676 ---help---
677 This option is needed for RDC R-321x system-on-chip, also known
678 as R-8610-(G).
679 If you don't have one of these chips, you should say N here.
680
681config X86_32_NON_STANDARD
682 bool "Support non-standard 32-bit SMP architectures"
683 depends on X86_32 && SMP
684 depends on X86_EXTENDED_PLATFORM
685 ---help---
686 This option compiles in the bigsmp and STA2X11 default
687 subarchitectures. It is intended for a generic binary
688 kernel. If you select them all, kernel will probe it one by
689 one and will fallback to default.
690
691# Alphabetically sorted list of Non standard 32 bit platforms
692
693config X86_SUPPORTS_MEMORY_FAILURE
694 def_bool y
695 # MCE code calls memory_failure():
696 depends on X86_MCE
697 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
698 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
699 depends on X86_64 || !SPARSEMEM
700 select ARCH_SUPPORTS_MEMORY_FAILURE
701
702config STA2X11
703 bool "STA2X11 Companion Chip Support"
704 depends on X86_32_NON_STANDARD && PCI
705 select ARCH_HAS_PHYS_TO_DMA
706 select X86_DEV_DMA_OPS
707 select X86_DMA_REMAP
708 select SWIOTLB
709 select MFD_STA2X11
710 select GPIOLIB
711 ---help---
712 This adds support for boards based on the STA2X11 IO-Hub,
713 a.k.a. "ConneXt". The chip is used in place of the standard
714 PC chipset, so all "standard" peripherals are missing. If this
715 option is selected the kernel will still be able to boot on
716 standard PC machines.
717
718config X86_32_IRIS
719 tristate "Eurobraille/Iris poweroff module"
720 depends on X86_32
721 ---help---
722 The Iris machines from EuroBraille do not have APM or ACPI support
723 to shut themselves down properly. A special I/O sequence is
724 needed to do so, which is what this module does at
725 kernel shutdown.
726
727 This is only for Iris machines from EuroBraille.
728
729 If unused, say N.
730
731config SCHED_OMIT_FRAME_POINTER
732 def_bool y
733 prompt "Single-depth WCHAN output"
734 depends on X86
735 ---help---
736 Calculate simpler /proc/<PID>/wchan values. If this option
737 is disabled then wchan values will recurse back to the
738 caller function. This provides more accurate wchan values,
739 at the expense of slightly more scheduling overhead.
740
741 If in doubt, say "Y".
742
743menuconfig HYPERVISOR_GUEST
744 bool "Linux guest support"
745 ---help---
746 Say Y here to enable options for running Linux under various hyper-
747 visors. This option enables basic hypervisor detection and platform
748 setup.
749
750 If you say N, all options in this submenu will be skipped and
751 disabled, and Linux guest support won't be built in.
752
753if HYPERVISOR_GUEST
754
755config PARAVIRT
756 bool "Enable paravirtualization code"
757 ---help---
758 This changes the kernel so it can modify itself when it is run
759 under a hypervisor, potentially improving performance significantly
760 over full virtualization. However, when run without a hypervisor
761 the kernel is theoretically slower and slightly larger.
762
763config PARAVIRT_XXL
764 bool
765
766config PARAVIRT_DEBUG
767 bool "paravirt-ops debugging"
768 depends on PARAVIRT && DEBUG_KERNEL
769 ---help---
770 Enable to debug paravirt_ops internals. Specifically, BUG if
771 a paravirt_op is missing when it is called.
772
773config PARAVIRT_SPINLOCKS
774 bool "Paravirtualization layer for spinlocks"
775 depends on PARAVIRT && SMP
776 ---help---
777 Paravirtualized spinlocks allow a pvops backend to replace the
778 spinlock implementation with something virtualization-friendly
779 (for example, block the virtual CPU rather than spinning).
780
781 It has a minimal impact on native kernels and gives a nice performance
782 benefit on paravirtualized KVM / Xen kernels.
783
784 If you are unsure how to answer this question, answer Y.
785
786config QUEUED_LOCK_STAT
787 bool "Paravirt queued spinlock statistics"
788 depends on PARAVIRT_SPINLOCKS && DEBUG_FS
789 ---help---
790 Enable the collection of statistical data on the slowpath
791 behavior of paravirtualized queued spinlocks and report
792 them on debugfs.
793
794source "arch/x86/xen/Kconfig"
795
796config KVM_GUEST
797 bool "KVM Guest support (including kvmclock)"
798 depends on PARAVIRT
799 select PARAVIRT_CLOCK
800 default y
801 ---help---
802 This option enables various optimizations for running under the KVM
803 hypervisor. It includes a paravirtualized clock, so that instead
804 of relying on a PIT (or probably other) emulation by the
805 underlying device model, the host provides the guest with
806 timing infrastructure such as time of day, and system time
807
808config PVH
809 bool "Support for running PVH guests"
810 ---help---
811 This option enables the PVH entry point for guest virtual machines
812 as specified in the x86/HVM direct boot ABI.
813
814config KVM_DEBUG_FS
815 bool "Enable debug information for KVM Guests in debugfs"
816 depends on KVM_GUEST && DEBUG_FS
817 ---help---
818 This option enables collection of various statistics for KVM guest.
819 Statistics are displayed in debugfs filesystem. Enabling this option
820 may incur significant overhead.
821
822config PARAVIRT_TIME_ACCOUNTING
823 bool "Paravirtual steal time accounting"
824 depends on PARAVIRT
825 ---help---
826 Select this option to enable fine granularity task steal time
827 accounting. Time spent executing other tasks in parallel with
828 the current vCPU is discounted from the vCPU power. To account for
829 that, there can be a small performance impact.
830
831 If in doubt, say N here.
832
833config PARAVIRT_CLOCK
834 bool
835
836config JAILHOUSE_GUEST
837 bool "Jailhouse non-root cell support"
838 depends on X86_64 && PCI
839 select X86_PM_TIMER
840 ---help---
841 This option allows to run Linux as guest in a Jailhouse non-root
842 cell. You can leave this option disabled if you only want to start
843 Jailhouse and run Linux afterwards in the root cell.
844
845endif #HYPERVISOR_GUEST
846
847source "arch/x86/Kconfig.cpu"
848
849config HPET_TIMER
850 def_bool X86_64
851 prompt "HPET Timer Support" if X86_32
852 ---help---
853 Use the IA-PC HPET (High Precision Event Timer) to manage
854 time in preference to the PIT and RTC, if a HPET is
855 present.
856 HPET is the next generation timer replacing legacy 8254s.
857 The HPET provides a stable time base on SMP
858 systems, unlike the TSC, but it is more expensive to access,
859 as it is off-chip. The interface used is documented
860 in the HPET spec, revision 1.
861
862 You can safely choose Y here. However, HPET will only be
863 activated if the platform and the BIOS support this feature.
864 Otherwise the 8254 will be used for timing services.
865
866 Choose N to continue using the legacy 8254 timer.
867
868config HPET_EMULATE_RTC
869 def_bool y
870 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
871
872config APB_TIMER
873 def_bool y if X86_INTEL_MID
874 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
875 select DW_APB_TIMER
876 depends on X86_INTEL_MID && SFI
877 help
878 APB timer is the replacement for 8254, HPET on X86 MID platforms.
879 The APBT provides a stable time base on SMP
880 systems, unlike the TSC, but it is more expensive to access,
881 as it is off-chip. APB timers are always running regardless of CPU
882 C states, they are used as per CPU clockevent device when possible.
883
884# Mark as expert because too many people got it wrong.
885# The code disables itself when not needed.
886config DMI
887 default y
888 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
889 bool "Enable DMI scanning" if EXPERT
890 ---help---
891 Enabled scanning of DMI to identify machine quirks. Say Y
892 here unless you have verified that your setup is not
893 affected by entries in the DMI blacklist. Required by PNP
894 BIOS code.
895
896config GART_IOMMU
897 bool "Old AMD GART IOMMU support"
898 select IOMMU_HELPER
899 select SWIOTLB
900 depends on X86_64 && PCI && AMD_NB
901 ---help---
902 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
903 GART based hardware IOMMUs.
904
905 The GART supports full DMA access for devices with 32-bit access
906 limitations, on systems with more than 3 GB. This is usually needed
907 for USB, sound, many IDE/SATA chipsets and some other devices.
908
909 Newer systems typically have a modern AMD IOMMU, supported via
910 the CONFIG_AMD_IOMMU=y config option.
911
912 In normal configurations this driver is only active when needed:
913 there's more than 3 GB of memory and the system contains a
914 32-bit limited device.
915
916 If unsure, say Y.
917
918config CALGARY_IOMMU
919 bool "IBM Calgary IOMMU support"
920 select IOMMU_HELPER
921 select SWIOTLB
922 depends on X86_64 && PCI
923 ---help---
924 Support for hardware IOMMUs in IBM's xSeries x366 and x460
925 systems. Needed to run systems with more than 3GB of memory
926 properly with 32-bit PCI devices that do not support DAC
927 (Double Address Cycle). Calgary also supports bus level
928 isolation, where all DMAs pass through the IOMMU. This
929 prevents them from going anywhere except their intended
930 destination. This catches hard-to-find kernel bugs and
931 mis-behaving drivers and devices that do not use the DMA-API
932 properly to set up their DMA buffers. The IOMMU can be
933 turned off at boot time with the iommu=off parameter.
934 Normally the kernel will make the right choice by itself.
935 If unsure, say Y.
936
937config CALGARY_IOMMU_ENABLED_BY_DEFAULT
938 def_bool y
939 prompt "Should Calgary be enabled by default?"
940 depends on CALGARY_IOMMU
941 ---help---
942 Should Calgary be enabled by default? if you choose 'y', Calgary
943 will be used (if it exists). If you choose 'n', Calgary will not be
944 used even if it exists. If you choose 'n' and would like to use
945 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
946 If unsure, say Y.
947
948config MAXSMP
949 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
950 depends on X86_64 && SMP && DEBUG_KERNEL
951 select CPUMASK_OFFSTACK
952 ---help---
953 Enable maximum number of CPUS and NUMA Nodes for this architecture.
954 If unsure, say N.
955
956#
957# The maximum number of CPUs supported:
958#
959# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
960# and which can be configured interactively in the
961# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
962#
963# The ranges are different on 32-bit and 64-bit kernels, depending on
964# hardware capabilities and scalability features of the kernel.
965#
966# ( If MAXSMP is enabled we just use the highest possible value and disable
967# interactive configuration. )
968#
969
970config NR_CPUS_RANGE_BEGIN
971 int
972 default NR_CPUS_RANGE_END if MAXSMP
973 default 1 if !SMP
974 default 2
975
976config NR_CPUS_RANGE_END
977 int
978 depends on X86_32
979 default 64 if SMP && X86_BIGSMP
980 default 8 if SMP && !X86_BIGSMP
981 default 1 if !SMP
982
983config NR_CPUS_RANGE_END
984 int
985 depends on X86_64
986 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK)
987 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
988 default 1 if !SMP
989
990config NR_CPUS_DEFAULT
991 int
992 depends on X86_32
993 default 32 if X86_BIGSMP
994 default 8 if SMP
995 default 1 if !SMP
996
997config NR_CPUS_DEFAULT
998 int
999 depends on X86_64
1000 default 8192 if MAXSMP
1001 default 64 if SMP
1002 default 1 if !SMP
1003
1004config NR_CPUS
1005 int "Maximum number of CPUs" if SMP && !MAXSMP
1006 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1007 default NR_CPUS_DEFAULT
1008 ---help---
1009 This allows you to specify the maximum number of CPUs which this
1010 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
1011 supported value is 8192, otherwise the maximum value is 512. The
1012 minimum value which makes sense is 2.
1013
1014 This is purely to save memory: each supported CPU adds about 8KB
1015 to the kernel image.
1016
1017config SCHED_SMT
1018 def_bool y if SMP
1019
1020config SCHED_MC
1021 def_bool y
1022 prompt "Multi-core scheduler support"
1023 depends on SMP
1024 ---help---
1025 Multi-core scheduler support improves the CPU scheduler's decision
1026 making when dealing with multi-core CPU chips at a cost of slightly
1027 increased overhead in some places. If unsure say N here.
1028
1029config SCHED_MC_PRIO
1030 bool "CPU core priorities scheduler support"
1031 depends on SCHED_MC && CPU_SUP_INTEL
1032 select X86_INTEL_PSTATE
1033 select CPU_FREQ
1034 default y
1035 ---help---
1036 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1037 core ordering determined at manufacturing time, which allows
1038 certain cores to reach higher turbo frequencies (when running
1039 single threaded workloads) than others.
1040
1041 Enabling this kernel feature teaches the scheduler about
1042 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1043 scheduler's CPU selection logic accordingly, so that higher
1044 overall system performance can be achieved.
1045
1046 This feature will have no effect on CPUs without this feature.
1047
1048 If unsure say Y here.
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 depends on X86_32
1176 ---help---
1177 This option allows user programs to put the CPU into V8086
1178 mode, which is an 80286-era approximation of 16-bit real mode.
1179
1180 Some very old versions of X and/or vbetool require this option
1181 for user mode setting. Similarly, DOSEMU will use it if
1182 available to accelerate real mode DOS programs. However, any
1183 recent version of DOSEMU, X, or vbetool should be fully
1184 functional even without kernel VM86 support, as they will all
1185 fall back to software emulation. Nevertheless, if you are using
1186 a 16-bit DOS program where 16-bit performance matters, vm86
1187 mode might be faster than emulation and you might want to
1188 enable this option.
1189
1190 Note that any app that works on a 64-bit kernel is unlikely to
1191 need this option, as 64-bit kernels don't, and can't, support
1192 V8086 mode. This option is also unrelated to 16-bit protected
1193 mode and is not needed to run most 16-bit programs under Wine.
1194
1195 Enabling this option increases the complexity of the kernel
1196 and slows down exception handling a tiny bit.
1197
1198 If unsure, say N here.
1199
1200config VM86
1201 bool
1202 default X86_LEGACY_VM86
1203
1204config X86_16BIT
1205 bool "Enable support for 16-bit segments" if EXPERT
1206 default y
1207 depends on MODIFY_LDT_SYSCALL
1208 ---help---
1209 This option is required by programs like Wine to run 16-bit
1210 protected mode legacy code on x86 processors. Disabling
1211 this option saves about 300 bytes on i386, or around 6K text
1212 plus 16K runtime memory on x86-64,
1213
1214config X86_ESPFIX32
1215 def_bool y
1216 depends on X86_16BIT && X86_32
1217
1218config X86_ESPFIX64
1219 def_bool y
1220 depends on X86_16BIT && X86_64
1221
1222config X86_VSYSCALL_EMULATION
1223 bool "Enable vsyscall emulation" if EXPERT
1224 default y
1225 depends on X86_64
1226 ---help---
1227 This enables emulation of the legacy vsyscall page. Disabling
1228 it is roughly equivalent to booting with vsyscall=none, except
1229 that it will also disable the helpful warning if a program
1230 tries to use a vsyscall. With this option set to N, offending
1231 programs will just segfault, citing addresses of the form
1232 0xffffffffff600?00.
1233
1234 This option is required by many programs built before 2013, and
1235 care should be used even with newer programs if set to N.
1236
1237 Disabling this option saves about 7K of kernel size and
1238 possibly 4K of additional runtime pagetable memory.
1239
1240config TOSHIBA
1241 tristate "Toshiba Laptop support"
1242 depends on X86_32
1243 ---help---
1244 This adds a driver to safely access the System Management Mode of
1245 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1246 not work on models with a Phoenix BIOS. The System Management Mode
1247 is used to set the BIOS and power saving options on Toshiba portables.
1248
1249 For information on utilities to make use of this driver see the
1250 Toshiba Linux utilities web site at:
1251 <http://www.buzzard.org.uk/toshiba/>.
1252
1253 Say Y if you intend to run this kernel on a Toshiba portable.
1254 Say N otherwise.
1255
1256config I8K
1257 tristate "Dell i8k legacy laptop support"
1258 select HWMON
1259 select SENSORS_DELL_SMM
1260 ---help---
1261 This option enables legacy /proc/i8k userspace interface in hwmon
1262 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1263 temperature and allows controlling fan speeds of Dell laptops via
1264 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1265 it reports also power and hotkey status. For fan speed control is
1266 needed userspace package i8kutils.
1267
1268 Say Y if you intend to run this kernel on old Dell laptops or want to
1269 use userspace package i8kutils.
1270 Say N otherwise.
1271
1272config X86_REBOOTFIXUPS
1273 bool "Enable X86 board specific fixups for reboot"
1274 depends on X86_32
1275 ---help---
1276 This enables chipset and/or board specific fixups to be done
1277 in order to get reboot to work correctly. This is only needed on
1278 some combinations of hardware and BIOS. The symptom, for which
1279 this config is intended, is when reboot ends with a stalled/hung
1280 system.
1281
1282 Currently, the only fixup is for the Geode machines using
1283 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1284
1285 Say Y if you want to enable the fixup. Currently, it's safe to
1286 enable this option even if you don't need it.
1287 Say N otherwise.
1288
1289config MICROCODE
1290 bool "CPU microcode loading support"
1291 default y
1292 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1293 select FW_LOADER
1294 ---help---
1295 If you say Y here, you will be able to update the microcode on
1296 Intel and AMD processors. The Intel support is for the IA32 family,
1297 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1298 AMD support is for families 0x10 and later. You will obviously need
1299 the actual microcode binary data itself which is not shipped with
1300 the Linux kernel.
1301
1302 The preferred method to load microcode from a detached initrd is described
1303 in Documentation/x86/microcode.txt. For that you need to enable
1304 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1305 initrd for microcode blobs.
1306
1307 In addition, you can build the microcode into the kernel. For that you
1308 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1309 config option.
1310
1311config MICROCODE_INTEL
1312 bool "Intel microcode loading support"
1313 depends on MICROCODE
1314 default MICROCODE
1315 select FW_LOADER
1316 ---help---
1317 This options enables microcode patch loading support for Intel
1318 processors.
1319
1320 For the current Intel microcode data package go to
1321 <https://downloadcenter.intel.com> and search for
1322 'Linux Processor Microcode Data File'.
1323
1324config MICROCODE_AMD
1325 bool "AMD microcode loading support"
1326 depends on MICROCODE
1327 select FW_LOADER
1328 ---help---
1329 If you select this option, microcode patch loading support for AMD
1330 processors will be enabled.
1331
1332config MICROCODE_OLD_INTERFACE
1333 def_bool y
1334 depends on MICROCODE
1335
1336config X86_MSR
1337 tristate "/dev/cpu/*/msr - Model-specific register support"
1338 ---help---
1339 This device gives privileged processes access to the x86
1340 Model-Specific Registers (MSRs). It is a character device with
1341 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1342 MSR accesses are directed to a specific CPU on multi-processor
1343 systems.
1344
1345config X86_CPUID
1346 tristate "/dev/cpu/*/cpuid - CPU information support"
1347 ---help---
1348 This device gives processes access to the x86 CPUID instruction to
1349 be executed on a specific processor. It is a character device
1350 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1351 /dev/cpu/31/cpuid.
1352
1353choice
1354 prompt "High Memory Support"
1355 default HIGHMEM4G
1356 depends on X86_32
1357
1358config NOHIGHMEM
1359 bool "off"
1360 ---help---
1361 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1362 However, the address space of 32-bit x86 processors is only 4
1363 Gigabytes large. That means that, if you have a large amount of
1364 physical memory, not all of it can be "permanently mapped" by the
1365 kernel. The physical memory that's not permanently mapped is called
1366 "high memory".
1367
1368 If you are compiling a kernel which will never run on a machine with
1369 more than 1 Gigabyte total physical RAM, answer "off" here (default
1370 choice and suitable for most users). This will result in a "3GB/1GB"
1371 split: 3GB are mapped so that each process sees a 3GB virtual memory
1372 space and the remaining part of the 4GB virtual memory space is used
1373 by the kernel to permanently map as much physical memory as
1374 possible.
1375
1376 If the machine has between 1 and 4 Gigabytes physical RAM, then
1377 answer "4GB" here.
1378
1379 If more than 4 Gigabytes is used then answer "64GB" here. This
1380 selection turns Intel PAE (Physical Address Extension) mode on.
1381 PAE implements 3-level paging on IA32 processors. PAE is fully
1382 supported by Linux, PAE mode is implemented on all recent Intel
1383 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1384 then the kernel will not boot on CPUs that don't support PAE!
1385
1386 The actual amount of total physical memory will either be
1387 auto detected or can be forced by using a kernel command line option
1388 such as "mem=256M". (Try "man bootparam" or see the documentation of
1389 your boot loader (lilo or loadlin) about how to pass options to the
1390 kernel at boot time.)
1391
1392 If unsure, say "off".
1393
1394config HIGHMEM4G
1395 bool "4GB"
1396 ---help---
1397 Select this if you have a 32-bit processor and between 1 and 4
1398 gigabytes of physical RAM.
1399
1400config HIGHMEM64G
1401 bool "64GB"
1402 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1403 select X86_PAE
1404 ---help---
1405 Select this if you have a 32-bit processor and more than 4
1406 gigabytes of physical RAM.
1407
1408endchoice
1409
1410choice
1411 prompt "Memory split" if EXPERT
1412 default VMSPLIT_3G
1413 depends on X86_32
1414 ---help---
1415 Select the desired split between kernel and user memory.
1416
1417 If the address range available to the kernel is less than the
1418 physical memory installed, the remaining memory will be available
1419 as "high memory". Accessing high memory is a little more costly
1420 than low memory, as it needs to be mapped into the kernel first.
1421 Note that increasing the kernel address space limits the range
1422 available to user programs, making the address space there
1423 tighter. Selecting anything other than the default 3G/1G split
1424 will also likely make your kernel incompatible with binary-only
1425 kernel modules.
1426
1427 If you are not absolutely sure what you are doing, leave this
1428 option alone!
1429
1430 config VMSPLIT_3G
1431 bool "3G/1G user/kernel split"
1432 config VMSPLIT_3G_OPT
1433 depends on !X86_PAE
1434 bool "3G/1G user/kernel split (for full 1G low memory)"
1435 config VMSPLIT_2G
1436 bool "2G/2G user/kernel split"
1437 config VMSPLIT_2G_OPT
1438 depends on !X86_PAE
1439 bool "2G/2G user/kernel split (for full 2G low memory)"
1440 config VMSPLIT_1G
1441 bool "1G/3G user/kernel split"
1442endchoice
1443
1444config PAGE_OFFSET
1445 hex
1446 default 0xB0000000 if VMSPLIT_3G_OPT
1447 default 0x80000000 if VMSPLIT_2G
1448 default 0x78000000 if VMSPLIT_2G_OPT
1449 default 0x40000000 if VMSPLIT_1G
1450 default 0xC0000000
1451 depends on X86_32
1452
1453config HIGHMEM
1454 def_bool y
1455 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1456
1457config X86_PAE
1458 bool "PAE (Physical Address Extension) Support"
1459 depends on X86_32 && !HIGHMEM4G
1460 select PHYS_ADDR_T_64BIT
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 X86_DIRECT_GBPAGES
1489 def_bool y
1490 depends on X86_64 && !DEBUG_PAGEALLOC
1491 ---help---
1492 Certain kernel features effectively disable kernel
1493 linear 1 GB mappings (even if the CPU otherwise
1494 supports them), so don't confuse the user by printing
1495 that we have them enabled.
1496
1497config X86_CPA_STATISTICS
1498 bool "Enable statistic for Change Page Attribute"
1499 depends on DEBUG_FS
1500 ---help---
1501 Expose statistics about the Change Page Attribute mechanims, which
1502 helps to determine the effectivness of preserving large and huge
1503 page mappings when mapping protections are changed.
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 select DYNAMIC_PHYSICAL_MASK
1512 select ARCH_USE_MEMREMAP_PROT
1513 ---help---
1514 Say yes to enable support for the encryption of system memory.
1515 This requires an AMD processor that supports Secure Memory
1516 Encryption (SME).
1517
1518config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1519 bool "Activate AMD Secure Memory Encryption (SME) by default"
1520 default y
1521 depends on AMD_MEM_ENCRYPT
1522 ---help---
1523 Say yes to have system memory encrypted by default if running on
1524 an AMD processor that supports Secure Memory Encryption (SME).
1525
1526 If set to Y, then the encryption of system memory can be
1527 deactivated with the mem_encrypt=off command line option.
1528
1529 If set to N, then the encryption of system memory can be
1530 activated with the mem_encrypt=on command line option.
1531
1532# Common NUMA Features
1533config NUMA
1534 bool "Numa Memory Allocation and Scheduler Support"
1535 depends on SMP
1536 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1537 default y if X86_BIGSMP
1538 ---help---
1539 Enable NUMA (Non Uniform Memory Access) support.
1540
1541 The kernel will try to allocate memory used by a CPU on the
1542 local memory controller of the CPU and add some more
1543 NUMA awareness to the kernel.
1544
1545 For 64-bit this is recommended if the system is Intel Core i7
1546 (or later), AMD Opteron, or EM64T NUMA.
1547
1548 For 32-bit this is only needed if you boot a 32-bit
1549 kernel on a 64-bit NUMA platform.
1550
1551 Otherwise, you should say N.
1552
1553config AMD_NUMA
1554 def_bool y
1555 prompt "Old style AMD Opteron NUMA detection"
1556 depends on X86_64 && NUMA && PCI
1557 ---help---
1558 Enable AMD NUMA node topology detection. You should say Y here if
1559 you have a multi processor AMD system. This uses an old method to
1560 read the NUMA configuration directly from the builtin Northbridge
1561 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1562 which also takes priority if both are compiled in.
1563
1564config X86_64_ACPI_NUMA
1565 def_bool y
1566 prompt "ACPI NUMA detection"
1567 depends on X86_64 && NUMA && ACPI && PCI
1568 select ACPI_NUMA
1569 ---help---
1570 Enable ACPI SRAT based node topology detection.
1571
1572# Some NUMA nodes have memory ranges that span
1573# other nodes. Even though a pfn is valid and
1574# between a node's start and end pfns, it may not
1575# reside on that node. See memmap_init_zone()
1576# for details.
1577config NODES_SPAN_OTHER_NODES
1578 def_bool y
1579 depends on X86_64_ACPI_NUMA
1580
1581config NUMA_EMU
1582 bool "NUMA emulation"
1583 depends on NUMA
1584 ---help---
1585 Enable NUMA emulation. A flat machine will be split
1586 into virtual nodes when booted with "numa=fake=N", where N is the
1587 number of nodes. This is only useful for debugging.
1588
1589config NODES_SHIFT
1590 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1591 range 1 10
1592 default "10" if MAXSMP
1593 default "6" if X86_64
1594 default "3"
1595 depends on NEED_MULTIPLE_NODES
1596 ---help---
1597 Specify the maximum number of NUMA Nodes available on the target
1598 system. Increases memory reserved to accommodate various tables.
1599
1600config ARCH_HAVE_MEMORY_PRESENT
1601 def_bool y
1602 depends on X86_32 && DISCONTIGMEM
1603
1604config ARCH_FLATMEM_ENABLE
1605 def_bool y
1606 depends on X86_32 && !NUMA
1607
1608config ARCH_DISCONTIGMEM_ENABLE
1609 def_bool y
1610 depends on NUMA && X86_32
1611
1612config ARCH_DISCONTIGMEM_DEFAULT
1613 def_bool y
1614 depends on NUMA && X86_32
1615
1616config ARCH_SPARSEMEM_ENABLE
1617 def_bool y
1618 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1619 select SPARSEMEM_STATIC if X86_32
1620 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1621
1622config ARCH_SPARSEMEM_DEFAULT
1623 def_bool y
1624 depends on X86_64
1625
1626config ARCH_SELECT_MEMORY_MODEL
1627 def_bool y
1628 depends on ARCH_SPARSEMEM_ENABLE
1629
1630config ARCH_MEMORY_PROBE
1631 bool "Enable sysfs memory/probe interface"
1632 depends on X86_64 && MEMORY_HOTPLUG
1633 help
1634 This option enables a sysfs memory/probe interface for testing.
1635 See Documentation/memory-hotplug.txt for more information.
1636 If you are unsure how to answer this question, answer N.
1637
1638config ARCH_PROC_KCORE_TEXT
1639 def_bool y
1640 depends on X86_64 && PROC_KCORE
1641
1642config ILLEGAL_POINTER_VALUE
1643 hex
1644 default 0 if X86_32
1645 default 0xdead000000000000 if X86_64
1646
1647config X86_PMEM_LEGACY_DEVICE
1648 bool
1649
1650config X86_PMEM_LEGACY
1651 tristate "Support non-standard NVDIMMs and ADR protected memory"
1652 depends on PHYS_ADDR_T_64BIT
1653 depends on BLK_DEV
1654 select X86_PMEM_LEGACY_DEVICE
1655 select LIBNVDIMM
1656 help
1657 Treat memory marked using the non-standard e820 type of 12 as used
1658 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1659 The kernel will offer these regions to the 'pmem' driver so
1660 they can be used for persistent storage.
1661
1662 Say Y if unsure.
1663
1664config HIGHPTE
1665 bool "Allocate 3rd-level pagetables from highmem"
1666 depends on HIGHMEM
1667 ---help---
1668 The VM uses one page table entry for each page of physical memory.
1669 For systems with a lot of RAM, this can be wasteful of precious
1670 low memory. Setting this option will put user-space page table
1671 entries in high memory.
1672
1673config X86_CHECK_BIOS_CORRUPTION
1674 bool "Check for low memory corruption"
1675 ---help---
1676 Periodically check for memory corruption in low memory, which
1677 is suspected to be caused by BIOS. Even when enabled in the
1678 configuration, it is disabled at runtime. Enable it by
1679 setting "memory_corruption_check=1" on the kernel command
1680 line. By default it scans the low 64k of memory every 60
1681 seconds; see the memory_corruption_check_size and
1682 memory_corruption_check_period parameters in
1683 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1684
1685 When enabled with the default parameters, this option has
1686 almost no overhead, as it reserves a relatively small amount
1687 of memory and scans it infrequently. It both detects corruption
1688 and prevents it from affecting the running system.
1689
1690 It is, however, intended as a diagnostic tool; if repeatable
1691 BIOS-originated corruption always affects the same memory,
1692 you can use memmap= to prevent the kernel from using that
1693 memory.
1694
1695config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1696 bool "Set the default setting of memory_corruption_check"
1697 depends on X86_CHECK_BIOS_CORRUPTION
1698 default y
1699 ---help---
1700 Set whether the default state of memory_corruption_check is
1701 on or off.
1702
1703config X86_RESERVE_LOW
1704 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1705 default 64
1706 range 4 640
1707 ---help---
1708 Specify the amount of low memory to reserve for the BIOS.
1709
1710 The first page contains BIOS data structures that the kernel
1711 must not use, so that page must always be reserved.
1712
1713 By default we reserve the first 64K of physical RAM, as a
1714 number of BIOSes are known to corrupt that memory range
1715 during events such as suspend/resume or monitor cable
1716 insertion, so it must not be used by the kernel.
1717
1718 You can set this to 4 if you are absolutely sure that you
1719 trust the BIOS to get all its memory reservations and usages
1720 right. If you know your BIOS have problems beyond the
1721 default 64K area, you can set this to 640 to avoid using the
1722 entire low memory range.
1723
1724 If you have doubts about the BIOS (e.g. suspend/resume does
1725 not work or there's kernel crashes after certain hardware
1726 hotplug events) then you might want to enable
1727 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1728 typical corruption patterns.
1729
1730 Leave this to the default value of 64 if you are unsure.
1731
1732config MATH_EMULATION
1733 bool
1734 depends on MODIFY_LDT_SYSCALL
1735 prompt "Math emulation" if X86_32
1736 ---help---
1737 Linux can emulate a math coprocessor (used for floating point
1738 operations) if you don't have one. 486DX and Pentium processors have
1739 a math coprocessor built in, 486SX and 386 do not, unless you added
1740 a 487DX or 387, respectively. (The messages during boot time can
1741 give you some hints here ["man dmesg"].) Everyone needs either a
1742 coprocessor or this emulation.
1743
1744 If you don't have a math coprocessor, you need to say Y here; if you
1745 say Y here even though you have a coprocessor, the coprocessor will
1746 be used nevertheless. (This behavior can be changed with the kernel
1747 command line option "no387", which comes handy if your coprocessor
1748 is broken. Try "man bootparam" or see the documentation of your boot
1749 loader (lilo or loadlin) about how to pass options to the kernel at
1750 boot time.) This means that it is a good idea to say Y here if you
1751 intend to use this kernel on different machines.
1752
1753 More information about the internals of the Linux math coprocessor
1754 emulation can be found in <file:arch/x86/math-emu/README>.
1755
1756 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1757 kernel, it won't hurt.
1758
1759config MTRR
1760 def_bool y
1761 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1762 ---help---
1763 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1764 the Memory Type Range Registers (MTRRs) may be used to control
1765 processor access to memory ranges. This is most useful if you have
1766 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1767 allows bus write transfers to be combined into a larger transfer
1768 before bursting over the PCI/AGP bus. This can increase performance
1769 of image write operations 2.5 times or more. Saying Y here creates a
1770 /proc/mtrr file which may be used to manipulate your processor's
1771 MTRRs. Typically the X server should use this.
1772
1773 This code has a reasonably generic interface so that similar
1774 control registers on other processors can be easily supported
1775 as well:
1776
1777 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1778 Registers (ARRs) which provide a similar functionality to MTRRs. For
1779 these, the ARRs are used to emulate the MTRRs.
1780 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1781 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1782 write-combining. All of these processors are supported by this code
1783 and it makes sense to say Y here if you have one of them.
1784
1785 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1786 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1787 can lead to all sorts of problems, so it's good to say Y here.
1788
1789 You can safely say Y even if your machine doesn't have MTRRs, you'll
1790 just add about 9 KB to your kernel.
1791
1792 See <file:Documentation/x86/mtrr.txt> for more information.
1793
1794config MTRR_SANITIZER
1795 def_bool y
1796 prompt "MTRR cleanup support"
1797 depends on MTRR
1798 ---help---
1799 Convert MTRR layout from continuous to discrete, so X drivers can
1800 add writeback entries.
1801
1802 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1803 The largest mtrr entry size for a continuous block can be set with
1804 mtrr_chunk_size.
1805
1806 If unsure, say Y.
1807
1808config MTRR_SANITIZER_ENABLE_DEFAULT
1809 int "MTRR cleanup enable value (0-1)"
1810 range 0 1
1811 default "0"
1812 depends on MTRR_SANITIZER
1813 ---help---
1814 Enable mtrr cleanup default value
1815
1816config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1817 int "MTRR cleanup spare reg num (0-7)"
1818 range 0 7
1819 default "1"
1820 depends on MTRR_SANITIZER
1821 ---help---
1822 mtrr cleanup spare entries default, it can be changed via
1823 mtrr_spare_reg_nr=N on the kernel command line.
1824
1825config X86_PAT
1826 def_bool y
1827 prompt "x86 PAT support" if EXPERT
1828 depends on MTRR
1829 ---help---
1830 Use PAT attributes to setup page level cache control.
1831
1832 PATs are the modern equivalents of MTRRs and are much more
1833 flexible than MTRRs.
1834
1835 Say N here if you see bootup problems (boot crash, boot hang,
1836 spontaneous reboots) or a non-working video driver.
1837
1838 If unsure, say Y.
1839
1840config ARCH_USES_PG_UNCACHED
1841 def_bool y
1842 depends on X86_PAT
1843
1844config ARCH_RANDOM
1845 def_bool y
1846 prompt "x86 architectural random number generator" if EXPERT
1847 ---help---
1848 Enable the x86 architectural RDRAND instruction
1849 (Intel Bull Mountain technology) to generate random numbers.
1850 If supported, this is a high bandwidth, cryptographically
1851 secure hardware random number generator.
1852
1853config X86_SMAP
1854 def_bool y
1855 prompt "Supervisor Mode Access Prevention" if EXPERT
1856 ---help---
1857 Supervisor Mode Access Prevention (SMAP) is a security
1858 feature in newer Intel processors. There is a small
1859 performance cost if this enabled and turned on; there is
1860 also a small increase in the kernel size if this is enabled.
1861
1862 If unsure, say Y.
1863
1864config X86_INTEL_UMIP
1865 def_bool y
1866 depends on CPU_SUP_INTEL
1867 prompt "Intel User Mode Instruction Prevention" if EXPERT
1868 ---help---
1869 The User Mode Instruction Prevention (UMIP) is a security
1870 feature in newer Intel processors. If enabled, a general
1871 protection fault is issued if the SGDT, SLDT, SIDT, SMSW
1872 or STR instructions are executed in user mode. These instructions
1873 unnecessarily expose information about the hardware state.
1874
1875 The vast majority of applications do not use these instructions.
1876 For the very few that do, software emulation is provided in
1877 specific cases in protected and virtual-8086 modes. Emulated
1878 results are dummy.
1879
1880config X86_INTEL_MPX
1881 prompt "Intel MPX (Memory Protection Extensions)"
1882 def_bool n
1883 # Note: only available in 64-bit mode due to VMA flags shortage
1884 depends on CPU_SUP_INTEL && X86_64
1885 select ARCH_USES_HIGH_VMA_FLAGS
1886 ---help---
1887 MPX provides hardware features that can be used in
1888 conjunction with compiler-instrumented code to check
1889 memory references. It is designed to detect buffer
1890 overflow or underflow bugs.
1891
1892 This option enables running applications which are
1893 instrumented or otherwise use MPX. It does not use MPX
1894 itself inside the kernel or to protect the kernel
1895 against bad memory references.
1896
1897 Enabling this option will make the kernel larger:
1898 ~8k of kernel text and 36 bytes of data on a 64-bit
1899 defconfig. It adds a long to the 'mm_struct' which
1900 will increase the kernel memory overhead of each
1901 process and adds some branches to paths used during
1902 exec() and munmap().
1903
1904 For details, see Documentation/x86/intel_mpx.txt
1905
1906 If unsure, say N.
1907
1908config X86_INTEL_MEMORY_PROTECTION_KEYS
1909 prompt "Intel Memory Protection Keys"
1910 def_bool y
1911 # Note: only available in 64-bit mode
1912 depends on CPU_SUP_INTEL && X86_64
1913 select ARCH_USES_HIGH_VMA_FLAGS
1914 select ARCH_HAS_PKEYS
1915 ---help---
1916 Memory Protection Keys provides a mechanism for enforcing
1917 page-based protections, but without requiring modification of the
1918 page tables when an application changes protection domains.
1919
1920 For details, see Documentation/x86/protection-keys.txt
1921
1922 If unsure, say y.
1923
1924config EFI
1925 bool "EFI runtime service support"
1926 depends on ACPI
1927 select UCS2_STRING
1928 select EFI_RUNTIME_WRAPPERS
1929 ---help---
1930 This enables the kernel to use EFI runtime services that are
1931 available (such as the EFI variable services).
1932
1933 This option is only useful on systems that have EFI firmware.
1934 In addition, you should use the latest ELILO loader available
1935 at <http://elilo.sourceforge.net> in order to take advantage
1936 of EFI runtime services. However, even with this option, the
1937 resultant kernel should continue to boot on existing non-EFI
1938 platforms.
1939
1940config EFI_STUB
1941 bool "EFI stub support"
1942 depends on EFI && !X86_USE_3DNOW
1943 select RELOCATABLE
1944 ---help---
1945 This kernel feature allows a bzImage to be loaded directly
1946 by EFI firmware without the use of a bootloader.
1947
1948 See Documentation/efi-stub.txt for more information.
1949
1950config EFI_MIXED
1951 bool "EFI mixed-mode support"
1952 depends on EFI_STUB && X86_64
1953 ---help---
1954 Enabling this feature allows a 64-bit kernel to be booted
1955 on a 32-bit firmware, provided that your CPU supports 64-bit
1956 mode.
1957
1958 Note that it is not possible to boot a mixed-mode enabled
1959 kernel via the EFI boot stub - a bootloader that supports
1960 the EFI handover protocol must be used.
1961
1962 If unsure, say N.
1963
1964config SECCOMP
1965 def_bool y
1966 prompt "Enable seccomp to safely compute untrusted bytecode"
1967 ---help---
1968 This kernel feature is useful for number crunching applications
1969 that may need to compute untrusted bytecode during their
1970 execution. By using pipes or other transports made available to
1971 the process as file descriptors supporting the read/write
1972 syscalls, it's possible to isolate those applications in
1973 their own address space using seccomp. Once seccomp is
1974 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1975 and the task is only allowed to execute a few safe syscalls
1976 defined by each seccomp mode.
1977
1978 If unsure, say Y. Only embedded should say N here.
1979
1980source "kernel/Kconfig.hz"
1981
1982config KEXEC
1983 bool "kexec system call"
1984 select KEXEC_CORE
1985 ---help---
1986 kexec is a system call that implements the ability to shutdown your
1987 current kernel, and to start another kernel. It is like a reboot
1988 but it is independent of the system firmware. And like a reboot
1989 you can start any kernel with it, not just Linux.
1990
1991 The name comes from the similarity to the exec system call.
1992
1993 It is an ongoing process to be certain the hardware in a machine
1994 is properly shutdown, so do not be surprised if this code does not
1995 initially work for you. As of this writing the exact hardware
1996 interface is strongly in flux, so no good recommendation can be
1997 made.
1998
1999config KEXEC_FILE
2000 bool "kexec file based system call"
2001 select KEXEC_CORE
2002 select BUILD_BIN2C
2003 depends on X86_64
2004 depends on CRYPTO=y
2005 depends on CRYPTO_SHA256=y
2006 ---help---
2007 This is new version of kexec system call. This system call is
2008 file based and takes file descriptors as system call argument
2009 for kernel and initramfs as opposed to list of segments as
2010 accepted by previous system call.
2011
2012config ARCH_HAS_KEXEC_PURGATORY
2013 def_bool KEXEC_FILE
2014
2015config KEXEC_VERIFY_SIG
2016 bool "Verify kernel signature during kexec_file_load() syscall"
2017 depends on KEXEC_FILE
2018 ---help---
2019 This option makes kernel signature verification mandatory for
2020 the kexec_file_load() syscall.
2021
2022 In addition to that option, you need to enable signature
2023 verification for the corresponding kernel image type being
2024 loaded in order for this to work.
2025
2026config KEXEC_BZIMAGE_VERIFY_SIG
2027 bool "Enable bzImage signature verification support"
2028 depends on KEXEC_VERIFY_SIG
2029 depends on SIGNED_PE_FILE_VERIFICATION
2030 select SYSTEM_TRUSTED_KEYRING
2031 ---help---
2032 Enable bzImage signature verification support.
2033
2034config CRASH_DUMP
2035 bool "kernel crash dumps"
2036 depends on X86_64 || (X86_32 && HIGHMEM)
2037 ---help---
2038 Generate crash dump after being started by kexec.
2039 This should be normally only set in special crash dump kernels
2040 which are loaded in the main kernel with kexec-tools into
2041 a specially reserved region and then later executed after
2042 a crash by kdump/kexec. The crash dump kernel must be compiled
2043 to a memory address not used by the main kernel or BIOS using
2044 PHYSICAL_START, or it must be built as a relocatable image
2045 (CONFIG_RELOCATABLE=y).
2046 For more details see Documentation/kdump/kdump.txt
2047
2048config KEXEC_JUMP
2049 bool "kexec jump"
2050 depends on KEXEC && HIBERNATION
2051 ---help---
2052 Jump between original kernel and kexeced kernel and invoke
2053 code in physical address mode via KEXEC
2054
2055config PHYSICAL_START
2056 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2057 default "0x1000000"
2058 ---help---
2059 This gives the physical address where the kernel is loaded.
2060
2061 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2062 bzImage will decompress itself to above physical address and
2063 run from there. Otherwise, bzImage will run from the address where
2064 it has been loaded by the boot loader and will ignore above physical
2065 address.
2066
2067 In normal kdump cases one does not have to set/change this option
2068 as now bzImage can be compiled as a completely relocatable image
2069 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2070 address. This option is mainly useful for the folks who don't want
2071 to use a bzImage for capturing the crash dump and want to use a
2072 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2073 to be specifically compiled to run from a specific memory area
2074 (normally a reserved region) and this option comes handy.
2075
2076 So if you are using bzImage for capturing the crash dump,
2077 leave the value here unchanged to 0x1000000 and set
2078 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2079 for capturing the crash dump change this value to start of
2080 the reserved region. In other words, it can be set based on
2081 the "X" value as specified in the "crashkernel=YM@XM"
2082 command line boot parameter passed to the panic-ed
2083 kernel. Please take a look at Documentation/kdump/kdump.txt
2084 for more details about crash dumps.
2085
2086 Usage of bzImage for capturing the crash dump is recommended as
2087 one does not have to build two kernels. Same kernel can be used
2088 as production kernel and capture kernel. Above option should have
2089 gone away after relocatable bzImage support is introduced. But it
2090 is present because there are users out there who continue to use
2091 vmlinux for dump capture. This option should go away down the
2092 line.
2093
2094 Don't change this unless you know what you are doing.
2095
2096config RELOCATABLE
2097 bool "Build a relocatable kernel"
2098 default y
2099 ---help---
2100 This builds a kernel image that retains relocation information
2101 so it can be loaded someplace besides the default 1MB.
2102 The relocations tend to make the kernel binary about 10% larger,
2103 but are discarded at runtime.
2104
2105 One use is for the kexec on panic case where the recovery kernel
2106 must live at a different physical address than the primary
2107 kernel.
2108
2109 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2110 it has been loaded at and the compile time physical address
2111 (CONFIG_PHYSICAL_START) is used as the minimum location.
2112
2113config RANDOMIZE_BASE
2114 bool "Randomize the address of the kernel image (KASLR)"
2115 depends on RELOCATABLE
2116 default y
2117 ---help---
2118 In support of Kernel Address Space Layout Randomization (KASLR),
2119 this randomizes the physical address at which the kernel image
2120 is decompressed and the virtual address where the kernel
2121 image is mapped, as a security feature that deters exploit
2122 attempts relying on knowledge of the location of kernel
2123 code internals.
2124
2125 On 64-bit, the kernel physical and virtual addresses are
2126 randomized separately. The physical address will be anywhere
2127 between 16MB and the top of physical memory (up to 64TB). The
2128 virtual address will be randomized from 16MB up to 1GB (9 bits
2129 of entropy). Note that this also reduces the memory space
2130 available to kernel modules from 1.5GB to 1GB.
2131
2132 On 32-bit, the kernel physical and virtual addresses are
2133 randomized together. They will be randomized from 16MB up to
2134 512MB (8 bits of entropy).
2135
2136 Entropy is generated using the RDRAND instruction if it is
2137 supported. If RDTSC is supported, its value is mixed into
2138 the entropy pool as well. If neither RDRAND nor RDTSC are
2139 supported, then entropy is read from the i8254 timer. The
2140 usable entropy is limited by the kernel being built using
2141 2GB addressing, and that PHYSICAL_ALIGN must be at a
2142 minimum of 2MB. As a result, only 10 bits of entropy are
2143 theoretically possible, but the implementations are further
2144 limited due to memory layouts.
2145
2146 If unsure, say Y.
2147
2148# Relocation on x86 needs some additional build support
2149config X86_NEED_RELOCS
2150 def_bool y
2151 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2152
2153config PHYSICAL_ALIGN
2154 hex "Alignment value to which kernel should be aligned"
2155 default "0x200000"
2156 range 0x2000 0x1000000 if X86_32
2157 range 0x200000 0x1000000 if X86_64
2158 ---help---
2159 This value puts the alignment restrictions on physical address
2160 where kernel is loaded and run from. Kernel is compiled for an
2161 address which meets above alignment restriction.
2162
2163 If bootloader loads the kernel at a non-aligned address and
2164 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2165 address aligned to above value and run from there.
2166
2167 If bootloader loads the kernel at a non-aligned address and
2168 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2169 load address and decompress itself to the address it has been
2170 compiled for and run from there. The address for which kernel is
2171 compiled already meets above alignment restrictions. Hence the
2172 end result is that kernel runs from a physical address meeting
2173 above alignment restrictions.
2174
2175 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2176 this value must be a multiple of 0x200000.
2177
2178 Don't change this unless you know what you are doing.
2179
2180config DYNAMIC_MEMORY_LAYOUT
2181 bool
2182 ---help---
2183 This option makes base addresses of vmalloc and vmemmap as well as
2184 __PAGE_OFFSET movable during boot.
2185
2186config RANDOMIZE_MEMORY
2187 bool "Randomize the kernel memory sections"
2188 depends on X86_64
2189 depends on RANDOMIZE_BASE
2190 select DYNAMIC_MEMORY_LAYOUT
2191 default RANDOMIZE_BASE
2192 ---help---
2193 Randomizes the base virtual address of kernel memory sections
2194 (physical memory mapping, vmalloc & vmemmap). This security feature
2195 makes exploits relying on predictable memory locations less reliable.
2196
2197 The order of allocations remains unchanged. Entropy is generated in
2198 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2199 configuration have in average 30,000 different possible virtual
2200 addresses for each memory section.
2201
2202 If unsure, say Y.
2203
2204config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2205 hex "Physical memory mapping padding" if EXPERT
2206 depends on RANDOMIZE_MEMORY
2207 default "0xa" if MEMORY_HOTPLUG
2208 default "0x0"
2209 range 0x1 0x40 if MEMORY_HOTPLUG
2210 range 0x0 0x40
2211 ---help---
2212 Define the padding in terabytes added to the existing physical
2213 memory size during kernel memory randomization. It is useful
2214 for memory hotplug support but reduces the entropy available for
2215 address randomization.
2216
2217 If unsure, leave at the default value.
2218
2219config HOTPLUG_CPU
2220 def_bool y
2221 depends on SMP
2222
2223config BOOTPARAM_HOTPLUG_CPU0
2224 bool "Set default setting of cpu0_hotpluggable"
2225 depends on HOTPLUG_CPU
2226 ---help---
2227 Set whether default state of cpu0_hotpluggable is on or off.
2228
2229 Say Y here to enable CPU0 hotplug by default. If this switch
2230 is turned on, there is no need to give cpu0_hotplug kernel
2231 parameter and the CPU0 hotplug feature is enabled by default.
2232
2233 Please note: there are two known CPU0 dependencies if you want
2234 to enable the CPU0 hotplug feature either by this switch or by
2235 cpu0_hotplug kernel parameter.
2236
2237 First, resume from hibernate or suspend always starts from CPU0.
2238 So hibernate and suspend are prevented if CPU0 is offline.
2239
2240 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2241 offline if any interrupt can not migrate out of CPU0. There may
2242 be other CPU0 dependencies.
2243
2244 Please make sure the dependencies are under your control before
2245 you enable this feature.
2246
2247 Say N if you don't want to enable CPU0 hotplug feature by default.
2248 You still can enable the CPU0 hotplug feature at boot by kernel
2249 parameter cpu0_hotplug.
2250
2251config DEBUG_HOTPLUG_CPU0
2252 def_bool n
2253 prompt "Debug CPU0 hotplug"
2254 depends on HOTPLUG_CPU
2255 ---help---
2256 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2257 soon as possible and boots up userspace with CPU0 offlined. User
2258 can online CPU0 back after boot time.
2259
2260 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2261 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2262 compilation or giving cpu0_hotplug kernel parameter at boot.
2263
2264 If unsure, say N.
2265
2266config COMPAT_VDSO
2267 def_bool n
2268 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2269 depends on COMPAT_32
2270 ---help---
2271 Certain buggy versions of glibc will crash if they are
2272 presented with a 32-bit vDSO that is not mapped at the address
2273 indicated in its segment table.
2274
2275 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2276 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2277 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2278 the only released version with the bug, but OpenSUSE 9
2279 contains a buggy "glibc 2.3.2".
2280
2281 The symptom of the bug is that everything crashes on startup, saying:
2282 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2283
2284 Saying Y here changes the default value of the vdso32 boot
2285 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2286 This works around the glibc bug but hurts performance.
2287
2288 If unsure, say N: if you are compiling your own kernel, you
2289 are unlikely to be using a buggy version of glibc.
2290
2291choice
2292 prompt "vsyscall table for legacy applications"
2293 depends on X86_64
2294 default LEGACY_VSYSCALL_EMULATE
2295 help
2296 Legacy user code that does not know how to find the vDSO expects
2297 to be able to issue three syscalls by calling fixed addresses in
2298 kernel space. Since this location is not randomized with ASLR,
2299 it can be used to assist security vulnerability exploitation.
2300
2301 This setting can be changed at boot time via the kernel command
2302 line parameter vsyscall=[emulate|none].
2303
2304 On a system with recent enough glibc (2.14 or newer) and no
2305 static binaries, you can say None without a performance penalty
2306 to improve security.
2307
2308 If unsure, select "Emulate".
2309
2310 config LEGACY_VSYSCALL_EMULATE
2311 bool "Emulate"
2312 help
2313 The kernel traps and emulates calls into the fixed
2314 vsyscall address mapping. This makes the mapping
2315 non-executable, but it still contains known contents,
2316 which could be used in certain rare security vulnerability
2317 exploits. This configuration is recommended when userspace
2318 still uses the vsyscall area.
2319
2320 config LEGACY_VSYSCALL_NONE
2321 bool "None"
2322 help
2323 There will be no vsyscall mapping at all. This will
2324 eliminate any risk of ASLR bypass due to the vsyscall
2325 fixed address mapping. Attempts to use the vsyscalls
2326 will be reported to dmesg, so that either old or
2327 malicious userspace programs can be identified.
2328
2329endchoice
2330
2331config CMDLINE_BOOL
2332 bool "Built-in kernel command line"
2333 ---help---
2334 Allow for specifying boot arguments to the kernel at
2335 build time. On some systems (e.g. embedded ones), it is
2336 necessary or convenient to provide some or all of the
2337 kernel boot arguments with the kernel itself (that is,
2338 to not rely on the boot loader to provide them.)
2339
2340 To compile command line arguments into the kernel,
2341 set this option to 'Y', then fill in the
2342 boot arguments in CONFIG_CMDLINE.
2343
2344 Systems with fully functional boot loaders (i.e. non-embedded)
2345 should leave this option set to 'N'.
2346
2347config CMDLINE
2348 string "Built-in kernel command string"
2349 depends on CMDLINE_BOOL
2350 default ""
2351 ---help---
2352 Enter arguments here that should be compiled into the kernel
2353 image and used at boot time. If the boot loader provides a
2354 command line at boot time, it is appended to this string to
2355 form the full kernel command line, when the system boots.
2356
2357 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2358 change this behavior.
2359
2360 In most cases, the command line (whether built-in or provided
2361 by the boot loader) should specify the device for the root
2362 file system.
2363
2364config CMDLINE_OVERRIDE
2365 bool "Built-in command line overrides boot loader arguments"
2366 depends on CMDLINE_BOOL
2367 ---help---
2368 Set this option to 'Y' to have the kernel ignore the boot loader
2369 command line, and use ONLY the built-in command line.
2370
2371 This is used to work around broken boot loaders. This should
2372 be set to 'N' under normal conditions.
2373
2374config MODIFY_LDT_SYSCALL
2375 bool "Enable the LDT (local descriptor table)" if EXPERT
2376 default y
2377 ---help---
2378 Linux can allow user programs to install a per-process x86
2379 Local Descriptor Table (LDT) using the modify_ldt(2) system
2380 call. This is required to run 16-bit or segmented code such as
2381 DOSEMU or some Wine programs. It is also used by some very old
2382 threading libraries.
2383
2384 Enabling this feature adds a small amount of overhead to
2385 context switches and increases the low-level kernel attack
2386 surface. Disabling it removes the modify_ldt(2) system call.
2387
2388 Saying 'N' here may make sense for embedded or server kernels.
2389
2390source "kernel/livepatch/Kconfig"
2391
2392endmenu
2393
2394config ARCH_HAS_ADD_PAGES
2395 def_bool y
2396 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2397
2398config ARCH_ENABLE_MEMORY_HOTPLUG
2399 def_bool y
2400 depends on X86_64 || (X86_32 && HIGHMEM)
2401
2402config ARCH_ENABLE_MEMORY_HOTREMOVE
2403 def_bool y
2404 depends on MEMORY_HOTPLUG
2405
2406config USE_PERCPU_NUMA_NODE_ID
2407 def_bool y
2408 depends on NUMA
2409
2410config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2411 def_bool y
2412 depends on X86_64 || X86_PAE
2413
2414config ARCH_ENABLE_HUGEPAGE_MIGRATION
2415 def_bool y
2416 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2417
2418config ARCH_ENABLE_THP_MIGRATION
2419 def_bool y
2420 depends on X86_64 && TRANSPARENT_HUGEPAGE
2421
2422menu "Power management and ACPI options"
2423
2424config ARCH_HIBERNATION_HEADER
2425 def_bool y
2426 depends on HIBERNATION
2427
2428source "kernel/power/Kconfig"
2429
2430source "drivers/acpi/Kconfig"
2431
2432source "drivers/sfi/Kconfig"
2433
2434config X86_APM_BOOT
2435 def_bool y
2436 depends on APM
2437
2438menuconfig APM
2439 tristate "APM (Advanced Power Management) BIOS support"
2440 depends on X86_32 && PM_SLEEP
2441 ---help---
2442 APM is a BIOS specification for saving power using several different
2443 techniques. This is mostly useful for battery powered laptops with
2444 APM compliant BIOSes. If you say Y here, the system time will be
2445 reset after a RESUME operation, the /proc/apm device will provide
2446 battery status information, and user-space programs will receive
2447 notification of APM "events" (e.g. battery status change).
2448
2449 If you select "Y" here, you can disable actual use of the APM
2450 BIOS by passing the "apm=off" option to the kernel at boot time.
2451
2452 Note that the APM support is almost completely disabled for
2453 machines with more than one CPU.
2454
2455 In order to use APM, you will need supporting software. For location
2456 and more information, read <file:Documentation/power/apm-acpi.txt>
2457 and the Battery Powered Linux mini-HOWTO, available from
2458 <http://www.tldp.org/docs.html#howto>.
2459
2460 This driver does not spin down disk drives (see the hdparm(8)
2461 manpage ("man 8 hdparm") for that), and it doesn't turn off
2462 VESA-compliant "green" monitors.
2463
2464 This driver does not support the TI 4000M TravelMate and the ACER
2465 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2466 desktop machines also don't have compliant BIOSes, and this driver
2467 may cause those machines to panic during the boot phase.
2468
2469 Generally, if you don't have a battery in your machine, there isn't
2470 much point in using this driver and you should say N. If you get
2471 random kernel OOPSes or reboots that don't seem to be related to
2472 anything, try disabling/enabling this option (or disabling/enabling
2473 APM in your BIOS).
2474
2475 Some other things you should try when experiencing seemingly random,
2476 "weird" problems:
2477
2478 1) make sure that you have enough swap space and that it is
2479 enabled.
2480 2) pass the "no-hlt" option to the kernel
2481 3) switch on floating point emulation in the kernel and pass
2482 the "no387" option to the kernel
2483 4) pass the "floppy=nodma" option to the kernel
2484 5) pass the "mem=4M" option to the kernel (thereby disabling
2485 all but the first 4 MB of RAM)
2486 6) make sure that the CPU is not over clocked.
2487 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2488 8) disable the cache from your BIOS settings
2489 9) install a fan for the video card or exchange video RAM
2490 10) install a better fan for the CPU
2491 11) exchange RAM chips
2492 12) exchange the motherboard.
2493
2494 To compile this driver as a module, choose M here: the
2495 module will be called apm.
2496
2497if APM
2498
2499config APM_IGNORE_USER_SUSPEND
2500 bool "Ignore USER SUSPEND"
2501 ---help---
2502 This option will ignore USER SUSPEND requests. On machines with a
2503 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2504 series notebooks, it is necessary to say Y because of a BIOS bug.
2505
2506config APM_DO_ENABLE
2507 bool "Enable PM at boot time"
2508 ---help---
2509 Enable APM features at boot time. From page 36 of the APM BIOS
2510 specification: "When disabled, the APM BIOS does not automatically
2511 power manage devices, enter the Standby State, enter the Suspend
2512 State, or take power saving steps in response to CPU Idle calls."
2513 This driver will make CPU Idle calls when Linux is idle (unless this
2514 feature is turned off -- see "Do CPU IDLE calls", below). This
2515 should always save battery power, but more complicated APM features
2516 will be dependent on your BIOS implementation. You may need to turn
2517 this option off if your computer hangs at boot time when using APM
2518 support, or if it beeps continuously instead of suspending. Turn
2519 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2520 T400CDT. This is off by default since most machines do fine without
2521 this feature.
2522
2523config APM_CPU_IDLE
2524 depends on CPU_IDLE
2525 bool "Make CPU Idle calls when idle"
2526 ---help---
2527 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2528 On some machines, this can activate improved power savings, such as
2529 a slowed CPU clock rate, when the machine is idle. These idle calls
2530 are made after the idle loop has run for some length of time (e.g.,
2531 333 mS). On some machines, this will cause a hang at boot time or
2532 whenever the CPU becomes idle. (On machines with more than one CPU,
2533 this option does nothing.)
2534
2535config APM_DISPLAY_BLANK
2536 bool "Enable console blanking using APM"
2537 ---help---
2538 Enable console blanking using the APM. Some laptops can use this to
2539 turn off the LCD backlight when the screen blanker of the Linux
2540 virtual console blanks the screen. Note that this is only used by
2541 the virtual console screen blanker, and won't turn off the backlight
2542 when using the X Window system. This also doesn't have anything to
2543 do with your VESA-compliant power-saving monitor. Further, this
2544 option doesn't work for all laptops -- it might not turn off your
2545 backlight at all, or it might print a lot of errors to the console,
2546 especially if you are using gpm.
2547
2548config APM_ALLOW_INTS
2549 bool "Allow interrupts during APM BIOS calls"
2550 ---help---
2551 Normally we disable external interrupts while we are making calls to
2552 the APM BIOS as a measure to lessen the effects of a badly behaving
2553 BIOS implementation. The BIOS should reenable interrupts if it
2554 needs to. Unfortunately, some BIOSes do not -- especially those in
2555 many of the newer IBM Thinkpads. If you experience hangs when you
2556 suspend, try setting this to Y. Otherwise, say N.
2557
2558endif # APM
2559
2560source "drivers/cpufreq/Kconfig"
2561
2562source "drivers/cpuidle/Kconfig"
2563
2564source "drivers/idle/Kconfig"
2565
2566endmenu
2567
2568
2569menu "Bus options (PCI etc.)"
2570
2571choice
2572 prompt "PCI access mode"
2573 depends on X86_32 && PCI
2574 default PCI_GOANY
2575 ---help---
2576 On PCI systems, the BIOS can be used to detect the PCI devices and
2577 determine their configuration. However, some old PCI motherboards
2578 have BIOS bugs and may crash if this is done. Also, some embedded
2579 PCI-based systems don't have any BIOS at all. Linux can also try to
2580 detect the PCI hardware directly without using the BIOS.
2581
2582 With this option, you can specify how Linux should detect the
2583 PCI devices. If you choose "BIOS", the BIOS will be used,
2584 if you choose "Direct", the BIOS won't be used, and if you
2585 choose "MMConfig", then PCI Express MMCONFIG will be used.
2586 If you choose "Any", the kernel will try MMCONFIG, then the
2587 direct access method and falls back to the BIOS if that doesn't
2588 work. If unsure, go with the default, which is "Any".
2589
2590config PCI_GOBIOS
2591 bool "BIOS"
2592
2593config PCI_GOMMCONFIG
2594 bool "MMConfig"
2595
2596config PCI_GODIRECT
2597 bool "Direct"
2598
2599config PCI_GOOLPC
2600 bool "OLPC XO-1"
2601 depends on OLPC
2602
2603config PCI_GOANY
2604 bool "Any"
2605
2606endchoice
2607
2608config PCI_BIOS
2609 def_bool y
2610 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2611
2612# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2613config PCI_DIRECT
2614 def_bool y
2615 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2616
2617config PCI_MMCONFIG
2618 bool "Support mmconfig PCI config space access" if X86_64
2619 default y
2620 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2621 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2622
2623config PCI_OLPC
2624 def_bool y
2625 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2626
2627config PCI_XEN
2628 def_bool y
2629 depends on PCI && XEN
2630 select SWIOTLB_XEN
2631
2632config MMCONF_FAM10H
2633 def_bool y
2634 depends on X86_64 && PCI_MMCONFIG && ACPI
2635
2636config PCI_CNB20LE_QUIRK
2637 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2638 depends on PCI
2639 help
2640 Read the PCI windows out of the CNB20LE host bridge. This allows
2641 PCI hotplug to work on systems with the CNB20LE chipset which do
2642 not have ACPI.
2643
2644 There's no public spec for this chipset, and this functionality
2645 is known to be incomplete.
2646
2647 You should say N unless you know you need this.
2648
2649config ISA_BUS
2650 bool "ISA bus support on modern systems" if EXPERT
2651 help
2652 Expose ISA bus device drivers and options available for selection and
2653 configuration. Enable this option if your target machine has an ISA
2654 bus. ISA is an older system, displaced by PCI and newer bus
2655 architectures -- if your target machine is modern, it probably does
2656 not have an ISA bus.
2657
2658 If unsure, say N.
2659
2660# x86_64 have no ISA slots, but can have ISA-style DMA.
2661config ISA_DMA_API
2662 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2663 default y
2664 help
2665 Enables ISA-style DMA support for devices requiring such controllers.
2666 If unsure, say Y.
2667
2668if X86_32
2669
2670config ISA
2671 bool "ISA support"
2672 ---help---
2673 Find out whether you have ISA slots on your motherboard. ISA is the
2674 name of a bus system, i.e. the way the CPU talks to the other stuff
2675 inside your box. Other bus systems are PCI, EISA, MicroChannel
2676 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2677 newer boards don't support it. If you have ISA, say Y, otherwise N.
2678
2679config SCx200
2680 tristate "NatSemi SCx200 support"
2681 ---help---
2682 This provides basic support for National Semiconductor's
2683 (now AMD's) Geode processors. The driver probes for the
2684 PCI-IDs of several on-chip devices, so its a good dependency
2685 for other scx200_* drivers.
2686
2687 If compiled as a module, the driver is named scx200.
2688
2689config SCx200HR_TIMER
2690 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2691 depends on SCx200
2692 default y
2693 ---help---
2694 This driver provides a clocksource built upon the on-chip
2695 27MHz high-resolution timer. Its also a workaround for
2696 NSC Geode SC-1100's buggy TSC, which loses time when the
2697 processor goes idle (as is done by the scheduler). The
2698 other workaround is idle=poll boot option.
2699
2700config OLPC
2701 bool "One Laptop Per Child support"
2702 depends on !X86_PAE
2703 select GPIOLIB
2704 select OF
2705 select OF_PROMTREE
2706 select IRQ_DOMAIN
2707 ---help---
2708 Add support for detecting the unique features of the OLPC
2709 XO hardware.
2710
2711config OLPC_XO1_PM
2712 bool "OLPC XO-1 Power Management"
2713 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2714 ---help---
2715 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2716
2717config OLPC_XO1_RTC
2718 bool "OLPC XO-1 Real Time Clock"
2719 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2720 ---help---
2721 Add support for the XO-1 real time clock, which can be used as a
2722 programmable wakeup source.
2723
2724config OLPC_XO1_SCI
2725 bool "OLPC XO-1 SCI extras"
2726 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2727 depends on INPUT=y
2728 select POWER_SUPPLY
2729 ---help---
2730 Add support for SCI-based features of the OLPC XO-1 laptop:
2731 - EC-driven system wakeups
2732 - Power button
2733 - Ebook switch
2734 - Lid switch
2735 - AC adapter status updates
2736 - Battery status updates
2737
2738config OLPC_XO15_SCI
2739 bool "OLPC XO-1.5 SCI extras"
2740 depends on OLPC && ACPI
2741 select POWER_SUPPLY
2742 ---help---
2743 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2744 - EC-driven system wakeups
2745 - AC adapter status updates
2746 - Battery status updates
2747
2748config ALIX
2749 bool "PCEngines ALIX System Support (LED setup)"
2750 select GPIOLIB
2751 ---help---
2752 This option enables system support for the PCEngines ALIX.
2753 At present this just sets up LEDs for GPIO control on
2754 ALIX2/3/6 boards. However, other system specific setup should
2755 get added here.
2756
2757 Note: You must still enable the drivers for GPIO and LED support
2758 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2759
2760 Note: You have to set alix.force=1 for boards with Award BIOS.
2761
2762config NET5501
2763 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2764 select GPIOLIB
2765 ---help---
2766 This option enables system support for the Soekris Engineering net5501.
2767
2768config GEOS
2769 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2770 select GPIOLIB
2771 depends on DMI
2772 ---help---
2773 This option enables system support for the Traverse Technologies GEOS.
2774
2775config TS5500
2776 bool "Technologic Systems TS-5500 platform support"
2777 depends on MELAN
2778 select CHECK_SIGNATURE
2779 select NEW_LEDS
2780 select LEDS_CLASS
2781 ---help---
2782 This option enables system support for the Technologic Systems TS-5500.
2783
2784endif # X86_32
2785
2786config AMD_NB
2787 def_bool y
2788 depends on CPU_SUP_AMD && PCI
2789
2790config X86_SYSFB
2791 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2792 help
2793 Firmwares often provide initial graphics framebuffers so the BIOS,
2794 bootloader or kernel can show basic video-output during boot for
2795 user-guidance and debugging. Historically, x86 used the VESA BIOS
2796 Extensions and EFI-framebuffers for this, which are mostly limited
2797 to x86.
2798 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2799 framebuffers so the new generic system-framebuffer drivers can be
2800 used on x86. If the framebuffer is not compatible with the generic
2801 modes, it is advertised as fallback platform framebuffer so legacy
2802 drivers like efifb, vesafb and uvesafb can pick it up.
2803 If this option is not selected, all system framebuffers are always
2804 marked as fallback platform framebuffers as usual.
2805
2806 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2807 not be able to pick up generic system framebuffers if this option
2808 is selected. You are highly encouraged to enable simplefb as
2809 replacement if you select this option. simplefb can correctly deal
2810 with generic system framebuffers. But you should still keep vesafb
2811 and others enabled as fallback if a system framebuffer is
2812 incompatible with simplefb.
2813
2814 If unsure, say Y.
2815
2816endmenu
2817
2818
2819menu "Binary Emulations"
2820
2821config IA32_EMULATION
2822 bool "IA32 Emulation"
2823 depends on X86_64
2824 select ARCH_WANT_OLD_COMPAT_IPC
2825 select BINFMT_ELF
2826 select COMPAT_BINFMT_ELF
2827 select COMPAT_OLD_SIGACTION
2828 ---help---
2829 Include code to run legacy 32-bit programs under a
2830 64-bit kernel. You should likely turn this on, unless you're
2831 100% sure that you don't have any 32-bit programs left.
2832
2833config IA32_AOUT
2834 tristate "IA32 a.out support"
2835 depends on IA32_EMULATION
2836 depends on BROKEN
2837 ---help---
2838 Support old a.out binaries in the 32bit emulation.
2839
2840config X86_X32
2841 bool "x32 ABI for 64-bit mode"
2842 depends on X86_64
2843 ---help---
2844 Include code to run binaries for the x32 native 32-bit ABI
2845 for 64-bit processors. An x32 process gets access to the
2846 full 64-bit register file and wide data path while leaving
2847 pointers at 32 bits for smaller memory footprint.
2848
2849 You will need a recent binutils (2.22 or later) with
2850 elf32_x86_64 support enabled to compile a kernel with this
2851 option set.
2852
2853config COMPAT_32
2854 def_bool y
2855 depends on IA32_EMULATION || X86_32
2856 select HAVE_UID16
2857 select OLD_SIGSUSPEND3
2858
2859config COMPAT
2860 def_bool y
2861 depends on IA32_EMULATION || X86_X32
2862
2863if COMPAT
2864config COMPAT_FOR_U64_ALIGNMENT
2865 def_bool y
2866
2867config SYSVIPC_COMPAT
2868 def_bool y
2869 depends on SYSVIPC
2870endif
2871
2872endmenu
2873
2874
2875config HAVE_ATOMIC_IOMAP
2876 def_bool y
2877 depends on X86_32
2878
2879config X86_DEV_DMA_OPS
2880 bool
2881 depends on X86_64 || STA2X11
2882
2883config X86_DMA_REMAP
2884 bool
2885 depends on STA2X11
2886
2887config HAVE_GENERIC_GUP
2888 def_bool y
2889
2890source "drivers/firmware/Kconfig"
2891
2892source "arch/x86/kvm/Kconfig"