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1 # SPDX-License-Identifier: GPL-2.0
2 # Select 32 or 64 bit
3 config 64BIT
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
6 ---help---
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
9
10 config X86_32
11 def_bool y
12 depends on !64BIT
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
15 select CLKSRC_I8253
16 select CLONE_BACKWARDS
17 select HAVE_DEBUG_STACKOVERFLOW
18 select MODULES_USE_ELF_REL
19 select OLD_SIGACTION
20 select GENERIC_VDSO_32
21
22 config X86_64
23 def_bool y
24 depends on 64BIT
25 # Options that are inherently 64-bit kernel only:
26 select ARCH_HAS_GIGANTIC_PAGE
27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
28 select ARCH_USE_CMPXCHG_LOCKREF
29 select HAVE_ARCH_SOFT_DIRTY
30 select MODULES_USE_ELF_RELA
31 select NEED_DMA_MAP_STATE
32 select SWIOTLB
33
34 config FORCE_DYNAMIC_FTRACE
35 def_bool y
36 depends on X86_32
37 depends on FUNCTION_TRACER
38 select DYNAMIC_FTRACE
39 help
40 We keep the static function tracing (!DYNAMIC_FTRACE) around
41 in order to test the non static function tracing in the
42 generic code, as other architectures still use it. But we
43 only need to keep it around for x86_64. No need to keep it
44 for x86_32. For x86_32, force DYNAMIC_FTRACE.
45 #
46 # Arch settings
47 #
48 # ( Note that options that are marked 'if X86_64' could in principle be
49 # ported to 32-bit as well. )
50 #
51 config X86
52 def_bool y
53 #
54 # Note: keep this list sorted alphabetically
55 #
56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
58 select ARCH_32BIT_OFF_T if X86_32
59 select ARCH_CLOCKSOURCE_INIT
60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
61 select ARCH_HAS_DEBUG_VIRTUAL
62 select ARCH_HAS_DEVMEM_IS_ALLOWED
63 select ARCH_HAS_ELF_RANDOMIZE
64 select ARCH_HAS_FAST_MULTIPLIER
65 select ARCH_HAS_FILTER_PGPROT
66 select ARCH_HAS_FORTIFY_SOURCE
67 select ARCH_HAS_GCOV_PROFILE_ALL
68 select ARCH_HAS_KCOV if X86_64
69 select ARCH_HAS_MEM_ENCRYPT
70 select ARCH_HAS_MEMBARRIER_SYNC_CORE
71 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
72 select ARCH_HAS_PMEM_API if X86_64
73 select ARCH_HAS_PTE_DEVMAP if X86_64
74 select ARCH_HAS_PTE_SPECIAL
75 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
76 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
77 select ARCH_HAS_SET_MEMORY
78 select ARCH_HAS_SET_DIRECT_MAP
79 select ARCH_HAS_STRICT_KERNEL_RWX
80 select ARCH_HAS_STRICT_MODULE_RWX
81 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
82 select ARCH_HAS_SYSCALL_WRAPPER
83 select ARCH_HAS_UBSAN_SANITIZE_ALL
84 select ARCH_HAVE_NMI_SAFE_CMPXCHG
85 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
86 select ARCH_MIGHT_HAVE_PC_PARPORT
87 select ARCH_MIGHT_HAVE_PC_SERIO
88 select ARCH_STACKWALK
89 select ARCH_SUPPORTS_ACPI
90 select ARCH_SUPPORTS_ATOMIC_RMW
91 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
92 select ARCH_USE_BUILTIN_BSWAP
93 select ARCH_USE_QUEUED_RWLOCKS
94 select ARCH_USE_QUEUED_SPINLOCKS
95 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
96 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
97 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
98 select ARCH_WANT_HUGE_PMD_SHARE
99 select ARCH_WANTS_THP_SWAP if X86_64
100 select BUILDTIME_TABLE_SORT
101 select CLKEVT_I8253
102 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
103 select CLOCKSOURCE_WATCHDOG
104 select DCACHE_WORD_ACCESS
105 select EDAC_ATOMIC_SCRUB
106 select EDAC_SUPPORT
107 select GENERIC_CLOCKEVENTS
108 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
109 select GENERIC_CLOCKEVENTS_MIN_ADJUST
110 select GENERIC_CMOS_UPDATE
111 select GENERIC_CPU_AUTOPROBE
112 select GENERIC_CPU_VULNERABILITIES
113 select GENERIC_EARLY_IOREMAP
114 select GENERIC_FIND_FIRST_BIT
115 select GENERIC_IOMAP
116 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
117 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
118 select GENERIC_IRQ_MIGRATION if SMP
119 select GENERIC_IRQ_PROBE
120 select GENERIC_IRQ_RESERVATION_MODE
121 select GENERIC_IRQ_SHOW
122 select GENERIC_PENDING_IRQ if SMP
123 select GENERIC_PTDUMP
124 select GENERIC_SMP_IDLE_THREAD
125 select GENERIC_STRNCPY_FROM_USER
126 select GENERIC_STRNLEN_USER
127 select GENERIC_TIME_VSYSCALL
128 select GENERIC_GETTIMEOFDAY
129 select GENERIC_VDSO_TIME_NS
130 select GUP_GET_PTE_LOW_HIGH if X86_PAE
131 select HARDIRQS_SW_RESEND
132 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
133 select HAVE_ACPI_APEI if ACPI
134 select HAVE_ACPI_APEI_NMI if ACPI
135 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
136 select HAVE_ARCH_AUDITSYSCALL
137 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
138 select HAVE_ARCH_JUMP_LABEL
139 select HAVE_ARCH_JUMP_LABEL_RELATIVE
140 select HAVE_ARCH_KASAN if X86_64
141 select HAVE_ARCH_KASAN_VMALLOC if X86_64
142 select HAVE_ARCH_KGDB
143 select HAVE_ARCH_MMAP_RND_BITS if MMU
144 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
145 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
146 select HAVE_ARCH_PREL32_RELOCATIONS
147 select HAVE_ARCH_SECCOMP_FILTER
148 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
149 select HAVE_ARCH_STACKLEAK
150 select HAVE_ARCH_TRACEHOOK
151 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
152 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
153 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
154 select HAVE_ARCH_VMAP_STACK if X86_64
155 select HAVE_ARCH_WITHIN_STACK_FRAMES
156 select HAVE_ASM_MODVERSIONS
157 select HAVE_CMPXCHG_DOUBLE
158 select HAVE_CMPXCHG_LOCAL
159 select HAVE_CONTEXT_TRACKING if X86_64
160 select HAVE_COPY_THREAD_TLS
161 select HAVE_C_RECORDMCOUNT
162 select HAVE_DEBUG_KMEMLEAK
163 select HAVE_DMA_CONTIGUOUS
164 select HAVE_DYNAMIC_FTRACE
165 select HAVE_DYNAMIC_FTRACE_WITH_REGS
166 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
167 select HAVE_EBPF_JIT
168 select HAVE_EFFICIENT_UNALIGNED_ACCESS
169 select HAVE_EISA
170 select HAVE_EXIT_THREAD
171 select HAVE_FAST_GUP
172 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
173 select HAVE_FTRACE_MCOUNT_RECORD
174 select HAVE_FUNCTION_GRAPH_TRACER
175 select HAVE_FUNCTION_TRACER
176 select HAVE_GCC_PLUGINS
177 select HAVE_HW_BREAKPOINT
178 select HAVE_IDE
179 select HAVE_IOREMAP_PROT
180 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
181 select HAVE_IRQ_TIME_ACCOUNTING
182 select HAVE_KERNEL_BZIP2
183 select HAVE_KERNEL_GZIP
184 select HAVE_KERNEL_LZ4
185 select HAVE_KERNEL_LZMA
186 select HAVE_KERNEL_LZO
187 select HAVE_KERNEL_XZ
188 select HAVE_KPROBES
189 select HAVE_KPROBES_ON_FTRACE
190 select HAVE_FUNCTION_ERROR_INJECTION
191 select HAVE_KRETPROBES
192 select HAVE_KVM
193 select HAVE_LIVEPATCH if X86_64
194 select HAVE_MEMBLOCK_NODE_MAP
195 select HAVE_MIXED_BREAKPOINTS_REGS
196 select HAVE_MOD_ARCH_SPECIFIC
197 select HAVE_MOVE_PMD
198 select HAVE_NMI
199 select HAVE_OPROFILE
200 select HAVE_OPTPROBES
201 select HAVE_PCSPKR_PLATFORM
202 select HAVE_PERF_EVENTS
203 select HAVE_PERF_EVENTS_NMI
204 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
205 select HAVE_PCI
206 select HAVE_PERF_REGS
207 select HAVE_PERF_USER_STACK_DUMP
208 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
209 select HAVE_REGS_AND_STACK_ACCESS_API
210 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
211 select HAVE_FUNCTION_ARG_ACCESS_API
212 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
213 select HAVE_STACK_VALIDATION if X86_64
214 select HAVE_RSEQ
215 select HAVE_SYSCALL_TRACEPOINTS
216 select HAVE_UNSTABLE_SCHED_CLOCK
217 select HAVE_USER_RETURN_NOTIFIER
218 select HAVE_GENERIC_VDSO
219 select HOTPLUG_SMT if SMP
220 select IRQ_FORCED_THREADING
221 select NEED_SG_DMA_LENGTH
222 select PCI_DOMAINS if PCI
223 select PCI_LOCKLESS_CONFIG if PCI
224 select PERF_EVENTS
225 select RTC_LIB
226 select RTC_MC146818_LIB
227 select SPARSE_IRQ
228 select SRCU
229 select SYSCTL_EXCEPTION_TRACE
230 select THREAD_INFO_IN_TASK
231 select USER_STACKTRACE_SUPPORT
232 select VIRT_TO_BUS
233 select X86_FEATURE_NAMES if PROC_FS
234 select PROC_PID_ARCH_STATUS if PROC_FS
235 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
236
237 config INSTRUCTION_DECODER
238 def_bool y
239 depends on KPROBES || PERF_EVENTS || UPROBES
240
241 config OUTPUT_FORMAT
242 string
243 default "elf32-i386" if X86_32
244 default "elf64-x86-64" if X86_64
245
246 config LOCKDEP_SUPPORT
247 def_bool y
248
249 config STACKTRACE_SUPPORT
250 def_bool y
251
252 config MMU
253 def_bool y
254
255 config ARCH_MMAP_RND_BITS_MIN
256 default 28 if 64BIT
257 default 8
258
259 config ARCH_MMAP_RND_BITS_MAX
260 default 32 if 64BIT
261 default 16
262
263 config ARCH_MMAP_RND_COMPAT_BITS_MIN
264 default 8
265
266 config ARCH_MMAP_RND_COMPAT_BITS_MAX
267 default 16
268
269 config SBUS
270 bool
271
272 config GENERIC_ISA_DMA
273 def_bool y
274 depends on ISA_DMA_API
275
276 config GENERIC_BUG
277 def_bool y
278 depends on BUG
279 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
280
281 config GENERIC_BUG_RELATIVE_POINTERS
282 bool
283
284 config ARCH_MAY_HAVE_PC_FDC
285 def_bool y
286 depends on ISA_DMA_API
287
288 config GENERIC_CALIBRATE_DELAY
289 def_bool y
290
291 config ARCH_HAS_CPU_RELAX
292 def_bool y
293
294 config ARCH_HAS_CACHE_LINE_SIZE
295 def_bool y
296
297 config ARCH_HAS_FILTER_PGPROT
298 def_bool y
299
300 config HAVE_SETUP_PER_CPU_AREA
301 def_bool y
302
303 config NEED_PER_CPU_EMBED_FIRST_CHUNK
304 def_bool y
305
306 config NEED_PER_CPU_PAGE_FIRST_CHUNK
307 def_bool y
308
309 config ARCH_HIBERNATION_POSSIBLE
310 def_bool y
311
312 config ARCH_SUSPEND_POSSIBLE
313 def_bool y
314
315 config ARCH_WANT_GENERAL_HUGETLB
316 def_bool y
317
318 config ZONE_DMA32
319 def_bool y if X86_64
320
321 config AUDIT_ARCH
322 def_bool y if X86_64
323
324 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
325 def_bool y
326
327 config KASAN_SHADOW_OFFSET
328 hex
329 depends on KASAN
330 default 0xdffffc0000000000
331
332 config HAVE_INTEL_TXT
333 def_bool y
334 depends on INTEL_IOMMU && ACPI
335
336 config X86_32_SMP
337 def_bool y
338 depends on X86_32 && SMP
339
340 config X86_64_SMP
341 def_bool y
342 depends on X86_64 && SMP
343
344 config X86_32_LAZY_GS
345 def_bool y
346 depends on X86_32 && !STACKPROTECTOR
347
348 config ARCH_SUPPORTS_UPROBES
349 def_bool y
350
351 config FIX_EARLYCON_MEM
352 def_bool y
353
354 config DYNAMIC_PHYSICAL_MASK
355 bool
356
357 config PGTABLE_LEVELS
358 int
359 default 5 if X86_5LEVEL
360 default 4 if X86_64
361 default 3 if X86_PAE
362 default 2
363
364 config CC_HAS_SANE_STACKPROTECTOR
365 bool
366 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
367 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
368 help
369 We have to make sure stack protector is unconditionally disabled if
370 the compiler produces broken code.
371
372 menu "Processor type and features"
373
374 config ZONE_DMA
375 bool "DMA memory allocation support" if EXPERT
376 default y
377 help
378 DMA memory allocation support allows devices with less than 32-bit
379 addressing to allocate within the first 16MB of address space.
380 Disable if no such devices will be used.
381
382 If unsure, say Y.
383
384 config SMP
385 bool "Symmetric multi-processing support"
386 ---help---
387 This enables support for systems with more than one CPU. If you have
388 a system with only one CPU, say N. If you have a system with more
389 than one CPU, say Y.
390
391 If you say N here, the kernel will run on uni- and multiprocessor
392 machines, but will use only one CPU of a multiprocessor machine. If
393 you say Y here, the kernel will run on many, but not all,
394 uniprocessor machines. On a uniprocessor machine, the kernel
395 will run faster if you say N here.
396
397 Note that if you say Y here and choose architecture "586" or
398 "Pentium" under "Processor family", the kernel will not work on 486
399 architectures. Similarly, multiprocessor kernels for the "PPro"
400 architecture may not work on all Pentium based boards.
401
402 People using multiprocessor machines who say Y here should also say
403 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
404 Management" code will be disabled if you say Y here.
405
406 See also <file:Documentation/x86/i386/IO-APIC.rst>,
407 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
408 <http://www.tldp.org/docs.html#howto>.
409
410 If you don't know what to do here, say N.
411
412 config X86_FEATURE_NAMES
413 bool "Processor feature human-readable names" if EMBEDDED
414 default y
415 ---help---
416 This option compiles in a table of x86 feature bits and corresponding
417 names. This is required to support /proc/cpuinfo and a few kernel
418 messages. You can disable this to save space, at the expense of
419 making those few kernel messages show numeric feature bits instead.
420
421 If in doubt, say Y.
422
423 config X86_X2APIC
424 bool "Support x2apic"
425 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
426 ---help---
427 This enables x2apic support on CPUs that have this feature.
428
429 This allows 32-bit apic IDs (so it can support very large systems),
430 and accesses the local apic via MSRs not via mmio.
431
432 If you don't know what to do here, say N.
433
434 config X86_MPPARSE
435 bool "Enable MPS table" if ACPI || SFI
436 default y
437 depends on X86_LOCAL_APIC
438 ---help---
439 For old smp systems that do not have proper acpi support. Newer systems
440 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
441
442 config GOLDFISH
443 def_bool y
444 depends on X86_GOLDFISH
445
446 config RETPOLINE
447 bool "Avoid speculative indirect branches in kernel"
448 default y
449 select STACK_VALIDATION if HAVE_STACK_VALIDATION
450 help
451 Compile kernel with the retpoline compiler options to guard against
452 kernel-to-user data leaks by avoiding speculative indirect
453 branches. Requires a compiler with -mindirect-branch=thunk-extern
454 support for full protection. The kernel may run slower.
455
456 config X86_CPU_RESCTRL
457 bool "x86 CPU resource control support"
458 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
459 select KERNFS
460 select PROC_CPU_RESCTRL if PROC_FS
461 help
462 Enable x86 CPU resource control support.
463
464 Provide support for the allocation and monitoring of system resources
465 usage by the CPU.
466
467 Intel calls this Intel Resource Director Technology
468 (Intel(R) RDT). More information about RDT can be found in the
469 Intel x86 Architecture Software Developer Manual.
470
471 AMD calls this AMD Platform Quality of Service (AMD QoS).
472 More information about AMD QoS can be found in the AMD64 Technology
473 Platform Quality of Service Extensions manual.
474
475 Say N if unsure.
476
477 if X86_32
478 config X86_BIGSMP
479 bool "Support for big SMP systems with more than 8 CPUs"
480 depends on SMP
481 ---help---
482 This option is needed for the systems that have more than 8 CPUs.
483
484 config X86_EXTENDED_PLATFORM
485 bool "Support for extended (non-PC) x86 platforms"
486 default y
487 ---help---
488 If you disable this option then the kernel will only support
489 standard PC platforms. (which covers the vast majority of
490 systems out there.)
491
492 If you enable this option then you'll be able to select support
493 for the following (non-PC) 32 bit x86 platforms:
494 Goldfish (Android emulator)
495 AMD Elan
496 RDC R-321x SoC
497 SGI 320/540 (Visual Workstation)
498 STA2X11-based (e.g. Northville)
499 Moorestown MID devices
500
501 If you have one of these systems, or if you want to build a
502 generic distribution kernel, say Y here - otherwise say N.
503 endif
504
505 if X86_64
506 config X86_EXTENDED_PLATFORM
507 bool "Support for extended (non-PC) x86 platforms"
508 default y
509 ---help---
510 If you disable this option then the kernel will only support
511 standard PC platforms. (which covers the vast majority of
512 systems out there.)
513
514 If you enable this option then you'll be able to select support
515 for the following (non-PC) 64 bit x86 platforms:
516 Numascale NumaChip
517 ScaleMP vSMP
518 SGI Ultraviolet
519
520 If you have one of these systems, or if you want to build a
521 generic distribution kernel, say Y here - otherwise say N.
522 endif
523 # This is an alphabetically sorted list of 64 bit extended platforms
524 # Please maintain the alphabetic order if and when there are additions
525 config X86_NUMACHIP
526 bool "Numascale NumaChip"
527 depends on X86_64
528 depends on X86_EXTENDED_PLATFORM
529 depends on NUMA
530 depends on SMP
531 depends on X86_X2APIC
532 depends on PCI_MMCONFIG
533 ---help---
534 Adds support for Numascale NumaChip large-SMP systems. Needed to
535 enable more than ~168 cores.
536 If you don't have one of these, you should say N here.
537
538 config X86_VSMP
539 bool "ScaleMP vSMP"
540 select HYPERVISOR_GUEST
541 select PARAVIRT
542 depends on X86_64 && PCI
543 depends on X86_EXTENDED_PLATFORM
544 depends on SMP
545 ---help---
546 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
547 supposed to run on these EM64T-based machines. Only choose this option
548 if you have one of these machines.
549
550 config X86_UV
551 bool "SGI Ultraviolet"
552 depends on X86_64
553 depends on X86_EXTENDED_PLATFORM
554 depends on NUMA
555 depends on EFI
556 depends on X86_X2APIC
557 depends on PCI
558 ---help---
559 This option is needed in order to support SGI Ultraviolet systems.
560 If you don't have one of these, you should say N here.
561
562 # Following is an alphabetically sorted list of 32 bit extended platforms
563 # Please maintain the alphabetic order if and when there are additions
564
565 config X86_GOLDFISH
566 bool "Goldfish (Virtual Platform)"
567 depends on X86_EXTENDED_PLATFORM
568 ---help---
569 Enable support for the Goldfish virtual platform used primarily
570 for Android development. Unless you are building for the Android
571 Goldfish emulator say N here.
572
573 config X86_INTEL_CE
574 bool "CE4100 TV platform"
575 depends on PCI
576 depends on PCI_GODIRECT
577 depends on X86_IO_APIC
578 depends on X86_32
579 depends on X86_EXTENDED_PLATFORM
580 select X86_REBOOTFIXUPS
581 select OF
582 select OF_EARLY_FLATTREE
583 ---help---
584 Select for the Intel CE media processor (CE4100) SOC.
585 This option compiles in support for the CE4100 SOC for settop
586 boxes and media devices.
587
588 config X86_INTEL_MID
589 bool "Intel MID platform support"
590 depends on X86_EXTENDED_PLATFORM
591 depends on X86_PLATFORM_DEVICES
592 depends on PCI
593 depends on X86_64 || (PCI_GOANY && X86_32)
594 depends on X86_IO_APIC
595 select SFI
596 select I2C
597 select DW_APB_TIMER
598 select APB_TIMER
599 select INTEL_SCU_IPC
600 select MFD_INTEL_MSIC
601 ---help---
602 Select to build a kernel capable of supporting Intel MID (Mobile
603 Internet Device) platform systems which do not have the PCI legacy
604 interfaces. If you are building for a PC class system say N here.
605
606 Intel MID platforms are based on an Intel processor and chipset which
607 consume less power than most of the x86 derivatives.
608
609 config X86_INTEL_QUARK
610 bool "Intel Quark platform support"
611 depends on X86_32
612 depends on X86_EXTENDED_PLATFORM
613 depends on X86_PLATFORM_DEVICES
614 depends on X86_TSC
615 depends on PCI
616 depends on PCI_GOANY
617 depends on X86_IO_APIC
618 select IOSF_MBI
619 select INTEL_IMR
620 select COMMON_CLK
621 ---help---
622 Select to include support for Quark X1000 SoC.
623 Say Y here if you have a Quark based system such as the Arduino
624 compatible Intel Galileo.
625
626 config X86_INTEL_LPSS
627 bool "Intel Low Power Subsystem Support"
628 depends on X86 && ACPI && PCI
629 select COMMON_CLK
630 select PINCTRL
631 select IOSF_MBI
632 ---help---
633 Select to build support for Intel Low Power Subsystem such as
634 found on Intel Lynxpoint PCH. Selecting this option enables
635 things like clock tree (common clock framework) and pincontrol
636 which are needed by the LPSS peripheral drivers.
637
638 config X86_AMD_PLATFORM_DEVICE
639 bool "AMD ACPI2Platform devices support"
640 depends on ACPI
641 select COMMON_CLK
642 select PINCTRL
643 ---help---
644 Select to interpret AMD specific ACPI device to platform device
645 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
646 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
647 implemented under PINCTRL subsystem.
648
649 config IOSF_MBI
650 tristate "Intel SoC IOSF Sideband support for SoC platforms"
651 depends on PCI
652 ---help---
653 This option enables sideband register access support for Intel SoC
654 platforms. On these platforms the IOSF sideband is used in lieu of
655 MSR's for some register accesses, mostly but not limited to thermal
656 and power. Drivers may query the availability of this device to
657 determine if they need the sideband in order to work on these
658 platforms. The sideband is available on the following SoC products.
659 This list is not meant to be exclusive.
660 - BayTrail
661 - Braswell
662 - Quark
663
664 You should say Y if you are running a kernel on one of these SoC's.
665
666 config IOSF_MBI_DEBUG
667 bool "Enable IOSF sideband access through debugfs"
668 depends on IOSF_MBI && DEBUG_FS
669 ---help---
670 Select this option to expose the IOSF sideband access registers (MCR,
671 MDR, MCRX) through debugfs to write and read register information from
672 different units on the SoC. This is most useful for obtaining device
673 state information for debug and analysis. As this is a general access
674 mechanism, users of this option would have specific knowledge of the
675 device they want to access.
676
677 If you don't require the option or are in doubt, say N.
678
679 config X86_RDC321X
680 bool "RDC R-321x SoC"
681 depends on X86_32
682 depends on X86_EXTENDED_PLATFORM
683 select M486
684 select X86_REBOOTFIXUPS
685 ---help---
686 This option is needed for RDC R-321x system-on-chip, also known
687 as R-8610-(G).
688 If you don't have one of these chips, you should say N here.
689
690 config X86_32_NON_STANDARD
691 bool "Support non-standard 32-bit SMP architectures"
692 depends on X86_32 && SMP
693 depends on X86_EXTENDED_PLATFORM
694 ---help---
695 This option compiles in the bigsmp and STA2X11 default
696 subarchitectures. It is intended for a generic binary
697 kernel. If you select them all, kernel will probe it one by
698 one and will fallback to default.
699
700 # Alphabetically sorted list of Non standard 32 bit platforms
701
702 config X86_SUPPORTS_MEMORY_FAILURE
703 def_bool y
704 # MCE code calls memory_failure():
705 depends on X86_MCE
706 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
707 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
708 depends on X86_64 || !SPARSEMEM
709 select ARCH_SUPPORTS_MEMORY_FAILURE
710
711 config STA2X11
712 bool "STA2X11 Companion Chip Support"
713 depends on X86_32_NON_STANDARD && PCI
714 select SWIOTLB
715 select MFD_STA2X11
716 select GPIOLIB
717 ---help---
718 This adds support for boards based on the STA2X11 IO-Hub,
719 a.k.a. "ConneXt". The chip is used in place of the standard
720 PC chipset, so all "standard" peripherals are missing. If this
721 option is selected the kernel will still be able to boot on
722 standard PC machines.
723
724 config X86_32_IRIS
725 tristate "Eurobraille/Iris poweroff module"
726 depends on X86_32
727 ---help---
728 The Iris machines from EuroBraille do not have APM or ACPI support
729 to shut themselves down properly. A special I/O sequence is
730 needed to do so, which is what this module does at
731 kernel shutdown.
732
733 This is only for Iris machines from EuroBraille.
734
735 If unused, say N.
736
737 config SCHED_OMIT_FRAME_POINTER
738 def_bool y
739 prompt "Single-depth WCHAN output"
740 depends on X86
741 ---help---
742 Calculate simpler /proc/<PID>/wchan values. If this option
743 is disabled then wchan values will recurse back to the
744 caller function. This provides more accurate wchan values,
745 at the expense of slightly more scheduling overhead.
746
747 If in doubt, say "Y".
748
749 menuconfig HYPERVISOR_GUEST
750 bool "Linux guest support"
751 ---help---
752 Say Y here to enable options for running Linux under various hyper-
753 visors. This option enables basic hypervisor detection and platform
754 setup.
755
756 If you say N, all options in this submenu will be skipped and
757 disabled, and Linux guest support won't be built in.
758
759 if HYPERVISOR_GUEST
760
761 config PARAVIRT
762 bool "Enable paravirtualization code"
763 ---help---
764 This changes the kernel so it can modify itself when it is run
765 under a hypervisor, potentially improving performance significantly
766 over full virtualization. However, when run without a hypervisor
767 the kernel is theoretically slower and slightly larger.
768
769 config PARAVIRT_XXL
770 bool
771
772 config PARAVIRT_DEBUG
773 bool "paravirt-ops debugging"
774 depends on PARAVIRT && DEBUG_KERNEL
775 ---help---
776 Enable to debug paravirt_ops internals. Specifically, BUG if
777 a paravirt_op is missing when it is called.
778
779 config PARAVIRT_SPINLOCKS
780 bool "Paravirtualization layer for spinlocks"
781 depends on PARAVIRT && SMP
782 ---help---
783 Paravirtualized spinlocks allow a pvops backend to replace the
784 spinlock implementation with something virtualization-friendly
785 (for example, block the virtual CPU rather than spinning).
786
787 It has a minimal impact on native kernels and gives a nice performance
788 benefit on paravirtualized KVM / Xen kernels.
789
790 If you are unsure how to answer this question, answer Y.
791
792 config X86_HV_CALLBACK_VECTOR
793 def_bool n
794
795 source "arch/x86/xen/Kconfig"
796
797 config KVM_GUEST
798 bool "KVM Guest support (including kvmclock)"
799 depends on PARAVIRT
800 select PARAVIRT_CLOCK
801 select ARCH_CPUIDLE_HALTPOLL
802 default y
803 ---help---
804 This option enables various optimizations for running under the KVM
805 hypervisor. It includes a paravirtualized clock, so that instead
806 of relying on a PIT (or probably other) emulation by the
807 underlying device model, the host provides the guest with
808 timing infrastructure such as time of day, and system time
809
810 config ARCH_CPUIDLE_HALTPOLL
811 def_bool n
812 prompt "Disable host haltpoll when loading haltpoll driver"
813 help
814 If virtualized under KVM, disable host haltpoll.
815
816 config PVH
817 bool "Support for running PVH guests"
818 ---help---
819 This option enables the PVH entry point for guest virtual machines
820 as specified in the x86/HVM direct boot ABI.
821
822 config KVM_DEBUG_FS
823 bool "Enable debug information for KVM Guests in debugfs"
824 depends on KVM_GUEST && DEBUG_FS
825 ---help---
826 This option enables collection of various statistics for KVM guest.
827 Statistics are displayed in debugfs filesystem. Enabling this option
828 may incur significant overhead.
829
830 config PARAVIRT_TIME_ACCOUNTING
831 bool "Paravirtual steal time accounting"
832 depends on PARAVIRT
833 ---help---
834 Select this option to enable fine granularity task steal time
835 accounting. Time spent executing other tasks in parallel with
836 the current vCPU is discounted from the vCPU power. To account for
837 that, there can be a small performance impact.
838
839 If in doubt, say N here.
840
841 config PARAVIRT_CLOCK
842 bool
843
844 config JAILHOUSE_GUEST
845 bool "Jailhouse non-root cell support"
846 depends on X86_64 && PCI
847 select X86_PM_TIMER
848 ---help---
849 This option allows to run Linux as guest in a Jailhouse non-root
850 cell. You can leave this option disabled if you only want to start
851 Jailhouse and run Linux afterwards in the root cell.
852
853 config ACRN_GUEST
854 bool "ACRN Guest support"
855 depends on X86_64
856 select X86_HV_CALLBACK_VECTOR
857 help
858 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
859 a flexible, lightweight reference open-source hypervisor, built with
860 real-time and safety-criticality in mind. It is built for embedded
861 IOT with small footprint and real-time features. More details can be
862 found in https://projectacrn.org/.
863
864 endif #HYPERVISOR_GUEST
865
866 source "arch/x86/Kconfig.cpu"
867
868 config HPET_TIMER
869 def_bool X86_64
870 prompt "HPET Timer Support" if X86_32
871 ---help---
872 Use the IA-PC HPET (High Precision Event Timer) to manage
873 time in preference to the PIT and RTC, if a HPET is
874 present.
875 HPET is the next generation timer replacing legacy 8254s.
876 The HPET provides a stable time base on SMP
877 systems, unlike the TSC, but it is more expensive to access,
878 as it is off-chip. The interface used is documented
879 in the HPET spec, revision 1.
880
881 You can safely choose Y here. However, HPET will only be
882 activated if the platform and the BIOS support this feature.
883 Otherwise the 8254 will be used for timing services.
884
885 Choose N to continue using the legacy 8254 timer.
886
887 config HPET_EMULATE_RTC
888 def_bool y
889 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
890
891 config APB_TIMER
892 def_bool y if X86_INTEL_MID
893 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
894 select DW_APB_TIMER
895 depends on X86_INTEL_MID && SFI
896 help
897 APB timer is the replacement for 8254, HPET on X86 MID platforms.
898 The APBT provides a stable time base on SMP
899 systems, unlike the TSC, but it is more expensive to access,
900 as it is off-chip. APB timers are always running regardless of CPU
901 C states, they are used as per CPU clockevent device when possible.
902
903 # Mark as expert because too many people got it wrong.
904 # The code disables itself when not needed.
905 config DMI
906 default y
907 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
908 bool "Enable DMI scanning" if EXPERT
909 ---help---
910 Enabled scanning of DMI to identify machine quirks. Say Y
911 here unless you have verified that your setup is not
912 affected by entries in the DMI blacklist. Required by PNP
913 BIOS code.
914
915 config GART_IOMMU
916 bool "Old AMD GART IOMMU support"
917 select IOMMU_HELPER
918 select SWIOTLB
919 depends on X86_64 && PCI && AMD_NB
920 ---help---
921 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
922 GART based hardware IOMMUs.
923
924 The GART supports full DMA access for devices with 32-bit access
925 limitations, on systems with more than 3 GB. This is usually needed
926 for USB, sound, many IDE/SATA chipsets and some other devices.
927
928 Newer systems typically have a modern AMD IOMMU, supported via
929 the CONFIG_AMD_IOMMU=y config option.
930
931 In normal configurations this driver is only active when needed:
932 there's more than 3 GB of memory and the system contains a
933 32-bit limited device.
934
935 If unsure, say Y.
936
937 config MAXSMP
938 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
939 depends on X86_64 && SMP && DEBUG_KERNEL
940 select CPUMASK_OFFSTACK
941 ---help---
942 Enable maximum number of CPUS and NUMA Nodes for this architecture.
943 If unsure, say N.
944
945 #
946 # The maximum number of CPUs supported:
947 #
948 # The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
949 # and which can be configured interactively in the
950 # [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
951 #
952 # The ranges are different on 32-bit and 64-bit kernels, depending on
953 # hardware capabilities and scalability features of the kernel.
954 #
955 # ( If MAXSMP is enabled we just use the highest possible value and disable
956 # interactive configuration. )
957 #
958
959 config NR_CPUS_RANGE_BEGIN
960 int
961 default NR_CPUS_RANGE_END if MAXSMP
962 default 1 if !SMP
963 default 2
964
965 config NR_CPUS_RANGE_END
966 int
967 depends on X86_32
968 default 64 if SMP && X86_BIGSMP
969 default 8 if SMP && !X86_BIGSMP
970 default 1 if !SMP
971
972 config NR_CPUS_RANGE_END
973 int
974 depends on X86_64
975 default 8192 if SMP && CPUMASK_OFFSTACK
976 default 512 if SMP && !CPUMASK_OFFSTACK
977 default 1 if !SMP
978
979 config NR_CPUS_DEFAULT
980 int
981 depends on X86_32
982 default 32 if X86_BIGSMP
983 default 8 if SMP
984 default 1 if !SMP
985
986 config NR_CPUS_DEFAULT
987 int
988 depends on X86_64
989 default 8192 if MAXSMP
990 default 64 if SMP
991 default 1 if !SMP
992
993 config NR_CPUS
994 int "Maximum number of CPUs" if SMP && !MAXSMP
995 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
996 default NR_CPUS_DEFAULT
997 ---help---
998 This allows you to specify the maximum number of CPUs which this
999 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
1000 supported value is 8192, otherwise the maximum value is 512. The
1001 minimum value which makes sense is 2.
1002
1003 This is purely to save memory: each supported CPU adds about 8KB
1004 to the kernel image.
1005
1006 config SCHED_SMT
1007 def_bool y if SMP
1008
1009 config SCHED_MC
1010 def_bool y
1011 prompt "Multi-core scheduler support"
1012 depends on SMP
1013 ---help---
1014 Multi-core scheduler support improves the CPU scheduler's decision
1015 making when dealing with multi-core CPU chips at a cost of slightly
1016 increased overhead in some places. If unsure say N here.
1017
1018 config SCHED_MC_PRIO
1019 bool "CPU core priorities scheduler support"
1020 depends on SCHED_MC && CPU_SUP_INTEL
1021 select X86_INTEL_PSTATE
1022 select CPU_FREQ
1023 default y
1024 ---help---
1025 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1026 core ordering determined at manufacturing time, which allows
1027 certain cores to reach higher turbo frequencies (when running
1028 single threaded workloads) than others.
1029
1030 Enabling this kernel feature teaches the scheduler about
1031 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1032 scheduler's CPU selection logic accordingly, so that higher
1033 overall system performance can be achieved.
1034
1035 This feature will have no effect on CPUs without this feature.
1036
1037 If unsure say Y here.
1038
1039 config UP_LATE_INIT
1040 def_bool y
1041 depends on !SMP && X86_LOCAL_APIC
1042
1043 config X86_UP_APIC
1044 bool "Local APIC support on uniprocessors" if !PCI_MSI
1045 default PCI_MSI
1046 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1047 ---help---
1048 A local APIC (Advanced Programmable Interrupt Controller) is an
1049 integrated interrupt controller in the CPU. If you have a single-CPU
1050 system which has a processor with a local APIC, you can say Y here to
1051 enable and use it. If you say Y here even though your machine doesn't
1052 have a local APIC, then the kernel will still run with no slowdown at
1053 all. The local APIC supports CPU-generated self-interrupts (timer,
1054 performance counters), and the NMI watchdog which detects hard
1055 lockups.
1056
1057 config X86_UP_IOAPIC
1058 bool "IO-APIC support on uniprocessors"
1059 depends on X86_UP_APIC
1060 ---help---
1061 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1062 SMP-capable replacement for PC-style interrupt controllers. Most
1063 SMP systems and many recent uniprocessor systems have one.
1064
1065 If you have a single-CPU system with an IO-APIC, you can say Y here
1066 to use it. If you say Y here even though your machine doesn't have
1067 an IO-APIC, then the kernel will still run with no slowdown at all.
1068
1069 config X86_LOCAL_APIC
1070 def_bool y
1071 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1072 select IRQ_DOMAIN_HIERARCHY
1073 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1074
1075 config X86_IO_APIC
1076 def_bool y
1077 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1078
1079 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1080 bool "Reroute for broken boot IRQs"
1081 depends on X86_IO_APIC
1082 ---help---
1083 This option enables a workaround that fixes a source of
1084 spurious interrupts. This is recommended when threaded
1085 interrupt handling is used on systems where the generation of
1086 superfluous "boot interrupts" cannot be disabled.
1087
1088 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1089 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1090 kernel does during interrupt handling). On chipsets where this
1091 boot IRQ generation cannot be disabled, this workaround keeps
1092 the original IRQ line masked so that only the equivalent "boot
1093 IRQ" is delivered to the CPUs. The workaround also tells the
1094 kernel to set up the IRQ handler on the boot IRQ line. In this
1095 way only one interrupt is delivered to the kernel. Otherwise
1096 the spurious second interrupt may cause the kernel to bring
1097 down (vital) interrupt lines.
1098
1099 Only affects "broken" chipsets. Interrupt sharing may be
1100 increased on these systems.
1101
1102 config X86_MCE
1103 bool "Machine Check / overheating reporting"
1104 select GENERIC_ALLOCATOR
1105 default y
1106 ---help---
1107 Machine Check support allows the processor to notify the
1108 kernel if it detects a problem (e.g. overheating, data corruption).
1109 The action the kernel takes depends on the severity of the problem,
1110 ranging from warning messages to halting the machine.
1111
1112 config X86_MCELOG_LEGACY
1113 bool "Support for deprecated /dev/mcelog character device"
1114 depends on X86_MCE
1115 ---help---
1116 Enable support for /dev/mcelog which is needed by the old mcelog
1117 userspace logging daemon. Consider switching to the new generation
1118 rasdaemon solution.
1119
1120 config X86_MCE_INTEL
1121 def_bool y
1122 prompt "Intel MCE features"
1123 depends on X86_MCE && X86_LOCAL_APIC
1124 ---help---
1125 Additional support for intel specific MCE features such as
1126 the thermal monitor.
1127
1128 config X86_MCE_AMD
1129 def_bool y
1130 prompt "AMD MCE features"
1131 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1132 ---help---
1133 Additional support for AMD specific MCE features such as
1134 the DRAM Error Threshold.
1135
1136 config X86_ANCIENT_MCE
1137 bool "Support for old Pentium 5 / WinChip machine checks"
1138 depends on X86_32 && X86_MCE
1139 ---help---
1140 Include support for machine check handling on old Pentium 5 or WinChip
1141 systems. These typically need to be enabled explicitly on the command
1142 line.
1143
1144 config X86_MCE_THRESHOLD
1145 depends on X86_MCE_AMD || X86_MCE_INTEL
1146 def_bool y
1147
1148 config X86_MCE_INJECT
1149 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1150 tristate "Machine check injector support"
1151 ---help---
1152 Provide support for injecting machine checks for testing purposes.
1153 If you don't know what a machine check is and you don't do kernel
1154 QA it is safe to say n.
1155
1156 config X86_THERMAL_VECTOR
1157 def_bool y
1158 depends on X86_MCE_INTEL
1159
1160 source "arch/x86/events/Kconfig"
1161
1162 config X86_LEGACY_VM86
1163 bool "Legacy VM86 support"
1164 depends on X86_32
1165 ---help---
1166 This option allows user programs to put the CPU into V8086
1167 mode, which is an 80286-era approximation of 16-bit real mode.
1168
1169 Some very old versions of X and/or vbetool require this option
1170 for user mode setting. Similarly, DOSEMU will use it if
1171 available to accelerate real mode DOS programs. However, any
1172 recent version of DOSEMU, X, or vbetool should be fully
1173 functional even without kernel VM86 support, as they will all
1174 fall back to software emulation. Nevertheless, if you are using
1175 a 16-bit DOS program where 16-bit performance matters, vm86
1176 mode might be faster than emulation and you might want to
1177 enable this option.
1178
1179 Note that any app that works on a 64-bit kernel is unlikely to
1180 need this option, as 64-bit kernels don't, and can't, support
1181 V8086 mode. This option is also unrelated to 16-bit protected
1182 mode and is not needed to run most 16-bit programs under Wine.
1183
1184 Enabling this option increases the complexity of the kernel
1185 and slows down exception handling a tiny bit.
1186
1187 If unsure, say N here.
1188
1189 config VM86
1190 bool
1191 default X86_LEGACY_VM86
1192
1193 config X86_16BIT
1194 bool "Enable support for 16-bit segments" if EXPERT
1195 default y
1196 depends on MODIFY_LDT_SYSCALL
1197 ---help---
1198 This option is required by programs like Wine to run 16-bit
1199 protected mode legacy code on x86 processors. Disabling
1200 this option saves about 300 bytes on i386, or around 6K text
1201 plus 16K runtime memory on x86-64,
1202
1203 config X86_ESPFIX32
1204 def_bool y
1205 depends on X86_16BIT && X86_32
1206
1207 config X86_ESPFIX64
1208 def_bool y
1209 depends on X86_16BIT && X86_64
1210
1211 config X86_VSYSCALL_EMULATION
1212 bool "Enable vsyscall emulation" if EXPERT
1213 default y
1214 depends on X86_64
1215 ---help---
1216 This enables emulation of the legacy vsyscall page. Disabling
1217 it is roughly equivalent to booting with vsyscall=none, except
1218 that it will also disable the helpful warning if a program
1219 tries to use a vsyscall. With this option set to N, offending
1220 programs will just segfault, citing addresses of the form
1221 0xffffffffff600?00.
1222
1223 This option is required by many programs built before 2013, and
1224 care should be used even with newer programs if set to N.
1225
1226 Disabling this option saves about 7K of kernel size and
1227 possibly 4K of additional runtime pagetable memory.
1228
1229 config X86_IOPL_IOPERM
1230 bool "IOPERM and IOPL Emulation"
1231 default y
1232 ---help---
1233 This enables the ioperm() and iopl() syscalls which are necessary
1234 for legacy applications.
1235
1236 Legacy IOPL support is an overbroad mechanism which allows user
1237 space aside of accessing all 65536 I/O ports also to disable
1238 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1239 capabilities and permission from potentially active security
1240 modules.
1241
1242 The emulation restricts the functionality of the syscall to
1243 only allowing the full range I/O port access, but prevents the
1244 ability to disable interrupts from user space which would be
1245 granted if the hardware IOPL mechanism would be used.
1246
1247 config TOSHIBA
1248 tristate "Toshiba Laptop support"
1249 depends on X86_32
1250 ---help---
1251 This adds a driver to safely access the System Management Mode of
1252 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1253 not work on models with a Phoenix BIOS. The System Management Mode
1254 is used to set the BIOS and power saving options on Toshiba portables.
1255
1256 For information on utilities to make use of this driver see the
1257 Toshiba Linux utilities web site at:
1258 <http://www.buzzard.org.uk/toshiba/>.
1259
1260 Say Y if you intend to run this kernel on a Toshiba portable.
1261 Say N otherwise.
1262
1263 config I8K
1264 tristate "Dell i8k legacy laptop support"
1265 select HWMON
1266 select SENSORS_DELL_SMM
1267 ---help---
1268 This option enables legacy /proc/i8k userspace interface in hwmon
1269 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1270 temperature and allows controlling fan speeds of Dell laptops via
1271 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1272 it reports also power and hotkey status. For fan speed control is
1273 needed userspace package i8kutils.
1274
1275 Say Y if you intend to run this kernel on old Dell laptops or want to
1276 use userspace package i8kutils.
1277 Say N otherwise.
1278
1279 config X86_REBOOTFIXUPS
1280 bool "Enable X86 board specific fixups for reboot"
1281 depends on X86_32
1282 ---help---
1283 This enables chipset and/or board specific fixups to be done
1284 in order to get reboot to work correctly. This is only needed on
1285 some combinations of hardware and BIOS. The symptom, for which
1286 this config is intended, is when reboot ends with a stalled/hung
1287 system.
1288
1289 Currently, the only fixup is for the Geode machines using
1290 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1291
1292 Say Y if you want to enable the fixup. Currently, it's safe to
1293 enable this option even if you don't need it.
1294 Say N otherwise.
1295
1296 config MICROCODE
1297 bool "CPU microcode loading support"
1298 default y
1299 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1300 select FW_LOADER
1301 ---help---
1302 If you say Y here, you will be able to update the microcode on
1303 Intel and AMD processors. The Intel support is for the IA32 family,
1304 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1305 AMD support is for families 0x10 and later. You will obviously need
1306 the actual microcode binary data itself which is not shipped with
1307 the Linux kernel.
1308
1309 The preferred method to load microcode from a detached initrd is described
1310 in Documentation/x86/microcode.rst. For that you need to enable
1311 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1312 initrd for microcode blobs.
1313
1314 In addition, you can build the microcode into the kernel. For that you
1315 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1316 config option.
1317
1318 config MICROCODE_INTEL
1319 bool "Intel microcode loading support"
1320 depends on MICROCODE
1321 default MICROCODE
1322 select FW_LOADER
1323 ---help---
1324 This options enables microcode patch loading support for Intel
1325 processors.
1326
1327 For the current Intel microcode data package go to
1328 <https://downloadcenter.intel.com> and search for
1329 'Linux Processor Microcode Data File'.
1330
1331 config MICROCODE_AMD
1332 bool "AMD microcode loading support"
1333 depends on MICROCODE
1334 select FW_LOADER
1335 ---help---
1336 If you select this option, microcode patch loading support for AMD
1337 processors will be enabled.
1338
1339 config MICROCODE_OLD_INTERFACE
1340 bool "Ancient loading interface (DEPRECATED)"
1341 default n
1342 depends on MICROCODE
1343 ---help---
1344 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1345 which was used by userspace tools like iucode_tool and microcode.ctl.
1346 It is inadequate because it runs too late to be able to properly
1347 load microcode on a machine and it needs special tools. Instead, you
1348 should've switched to the early loading method with the initrd or
1349 builtin microcode by now: Documentation/x86/microcode.rst
1350
1351 config X86_MSR
1352 tristate "/dev/cpu/*/msr - Model-specific register support"
1353 ---help---
1354 This device gives privileged processes access to the x86
1355 Model-Specific Registers (MSRs). It is a character device with
1356 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1357 MSR accesses are directed to a specific CPU on multi-processor
1358 systems.
1359
1360 config X86_CPUID
1361 tristate "/dev/cpu/*/cpuid - CPU information support"
1362 ---help---
1363 This device gives processes access to the x86 CPUID instruction to
1364 be executed on a specific processor. It is a character device
1365 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1366 /dev/cpu/31/cpuid.
1367
1368 choice
1369 prompt "High Memory Support"
1370 default HIGHMEM4G
1371 depends on X86_32
1372
1373 config NOHIGHMEM
1374 bool "off"
1375 ---help---
1376 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1377 However, the address space of 32-bit x86 processors is only 4
1378 Gigabytes large. That means that, if you have a large amount of
1379 physical memory, not all of it can be "permanently mapped" by the
1380 kernel. The physical memory that's not permanently mapped is called
1381 "high memory".
1382
1383 If you are compiling a kernel which will never run on a machine with
1384 more than 1 Gigabyte total physical RAM, answer "off" here (default
1385 choice and suitable for most users). This will result in a "3GB/1GB"
1386 split: 3GB are mapped so that each process sees a 3GB virtual memory
1387 space and the remaining part of the 4GB virtual memory space is used
1388 by the kernel to permanently map as much physical memory as
1389 possible.
1390
1391 If the machine has between 1 and 4 Gigabytes physical RAM, then
1392 answer "4GB" here.
1393
1394 If more than 4 Gigabytes is used then answer "64GB" here. This
1395 selection turns Intel PAE (Physical Address Extension) mode on.
1396 PAE implements 3-level paging on IA32 processors. PAE is fully
1397 supported by Linux, PAE mode is implemented on all recent Intel
1398 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1399 then the kernel will not boot on CPUs that don't support PAE!
1400
1401 The actual amount of total physical memory will either be
1402 auto detected or can be forced by using a kernel command line option
1403 such as "mem=256M". (Try "man bootparam" or see the documentation of
1404 your boot loader (lilo or loadlin) about how to pass options to the
1405 kernel at boot time.)
1406
1407 If unsure, say "off".
1408
1409 config HIGHMEM4G
1410 bool "4GB"
1411 ---help---
1412 Select this if you have a 32-bit processor and between 1 and 4
1413 gigabytes of physical RAM.
1414
1415 config HIGHMEM64G
1416 bool "64GB"
1417 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1418 select X86_PAE
1419 ---help---
1420 Select this if you have a 32-bit processor and more than 4
1421 gigabytes of physical RAM.
1422
1423 endchoice
1424
1425 choice
1426 prompt "Memory split" if EXPERT
1427 default VMSPLIT_3G
1428 depends on X86_32
1429 ---help---
1430 Select the desired split between kernel and user memory.
1431
1432 If the address range available to the kernel is less than the
1433 physical memory installed, the remaining memory will be available
1434 as "high memory". Accessing high memory is a little more costly
1435 than low memory, as it needs to be mapped into the kernel first.
1436 Note that increasing the kernel address space limits the range
1437 available to user programs, making the address space there
1438 tighter. Selecting anything other than the default 3G/1G split
1439 will also likely make your kernel incompatible with binary-only
1440 kernel modules.
1441
1442 If you are not absolutely sure what you are doing, leave this
1443 option alone!
1444
1445 config VMSPLIT_3G
1446 bool "3G/1G user/kernel split"
1447 config VMSPLIT_3G_OPT
1448 depends on !X86_PAE
1449 bool "3G/1G user/kernel split (for full 1G low memory)"
1450 config VMSPLIT_2G
1451 bool "2G/2G user/kernel split"
1452 config VMSPLIT_2G_OPT
1453 depends on !X86_PAE
1454 bool "2G/2G user/kernel split (for full 2G low memory)"
1455 config VMSPLIT_1G
1456 bool "1G/3G user/kernel split"
1457 endchoice
1458
1459 config PAGE_OFFSET
1460 hex
1461 default 0xB0000000 if VMSPLIT_3G_OPT
1462 default 0x80000000 if VMSPLIT_2G
1463 default 0x78000000 if VMSPLIT_2G_OPT
1464 default 0x40000000 if VMSPLIT_1G
1465 default 0xC0000000
1466 depends on X86_32
1467
1468 config HIGHMEM
1469 def_bool y
1470 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1471
1472 config X86_PAE
1473 bool "PAE (Physical Address Extension) Support"
1474 depends on X86_32 && !HIGHMEM4G
1475 select PHYS_ADDR_T_64BIT
1476 select SWIOTLB
1477 ---help---
1478 PAE is required for NX support, and furthermore enables
1479 larger swapspace support for non-overcommit purposes. It
1480 has the cost of more pagetable lookup overhead, and also
1481 consumes more pagetable space per process.
1482
1483 config X86_5LEVEL
1484 bool "Enable 5-level page tables support"
1485 default y
1486 select DYNAMIC_MEMORY_LAYOUT
1487 select SPARSEMEM_VMEMMAP
1488 depends on X86_64
1489 ---help---
1490 5-level paging enables access to larger address space:
1491 upto 128 PiB of virtual address space and 4 PiB of
1492 physical address space.
1493
1494 It will be supported by future Intel CPUs.
1495
1496 A kernel with the option enabled can be booted on machines that
1497 support 4- or 5-level paging.
1498
1499 See Documentation/x86/x86_64/5level-paging.rst for more
1500 information.
1501
1502 Say N if unsure.
1503
1504 config X86_DIRECT_GBPAGES
1505 def_bool y
1506 depends on X86_64
1507 ---help---
1508 Certain kernel features effectively disable kernel
1509 linear 1 GB mappings (even if the CPU otherwise
1510 supports them), so don't confuse the user by printing
1511 that we have them enabled.
1512
1513 config X86_CPA_STATISTICS
1514 bool "Enable statistic for Change Page Attribute"
1515 depends on DEBUG_FS
1516 ---help---
1517 Expose statistics about the Change Page Attribute mechanism, which
1518 helps to determine the effectiveness of preserving large and huge
1519 page mappings when mapping protections are changed.
1520
1521 config AMD_MEM_ENCRYPT
1522 bool "AMD Secure Memory Encryption (SME) support"
1523 depends on X86_64 && CPU_SUP_AMD
1524 select DYNAMIC_PHYSICAL_MASK
1525 select ARCH_USE_MEMREMAP_PROT
1526 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1527 ---help---
1528 Say yes to enable support for the encryption of system memory.
1529 This requires an AMD processor that supports Secure Memory
1530 Encryption (SME).
1531
1532 config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1533 bool "Activate AMD Secure Memory Encryption (SME) by default"
1534 default y
1535 depends on AMD_MEM_ENCRYPT
1536 ---help---
1537 Say yes to have system memory encrypted by default if running on
1538 an AMD processor that supports Secure Memory Encryption (SME).
1539
1540 If set to Y, then the encryption of system memory can be
1541 deactivated with the mem_encrypt=off command line option.
1542
1543 If set to N, then the encryption of system memory can be
1544 activated with the mem_encrypt=on command line option.
1545
1546 # Common NUMA Features
1547 config NUMA
1548 bool "NUMA Memory Allocation and Scheduler Support"
1549 depends on SMP
1550 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1551 default y if X86_BIGSMP
1552 ---help---
1553 Enable NUMA (Non-Uniform Memory Access) support.
1554
1555 The kernel will try to allocate memory used by a CPU on the
1556 local memory controller of the CPU and add some more
1557 NUMA awareness to the kernel.
1558
1559 For 64-bit this is recommended if the system is Intel Core i7
1560 (or later), AMD Opteron, or EM64T NUMA.
1561
1562 For 32-bit this is only needed if you boot a 32-bit
1563 kernel on a 64-bit NUMA platform.
1564
1565 Otherwise, you should say N.
1566
1567 config AMD_NUMA
1568 def_bool y
1569 prompt "Old style AMD Opteron NUMA detection"
1570 depends on X86_64 && NUMA && PCI
1571 ---help---
1572 Enable AMD NUMA node topology detection. You should say Y here if
1573 you have a multi processor AMD system. This uses an old method to
1574 read the NUMA configuration directly from the builtin Northbridge
1575 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1576 which also takes priority if both are compiled in.
1577
1578 config X86_64_ACPI_NUMA
1579 def_bool y
1580 prompt "ACPI NUMA detection"
1581 depends on X86_64 && NUMA && ACPI && PCI
1582 select ACPI_NUMA
1583 ---help---
1584 Enable ACPI SRAT based node topology detection.
1585
1586 # Some NUMA nodes have memory ranges that span
1587 # other nodes. Even though a pfn is valid and
1588 # between a node's start and end pfns, it may not
1589 # reside on that node. See memmap_init_zone()
1590 # for details.
1591 config NODES_SPAN_OTHER_NODES
1592 def_bool y
1593 depends on X86_64_ACPI_NUMA
1594
1595 config NUMA_EMU
1596 bool "NUMA emulation"
1597 depends on NUMA
1598 ---help---
1599 Enable NUMA emulation. A flat machine will be split
1600 into virtual nodes when booted with "numa=fake=N", where N is the
1601 number of nodes. This is only useful for debugging.
1602
1603 config NODES_SHIFT
1604 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1605 range 1 10
1606 default "10" if MAXSMP
1607 default "6" if X86_64
1608 default "3"
1609 depends on NEED_MULTIPLE_NODES
1610 ---help---
1611 Specify the maximum number of NUMA Nodes available on the target
1612 system. Increases memory reserved to accommodate various tables.
1613
1614 config ARCH_HAVE_MEMORY_PRESENT
1615 def_bool y
1616 depends on X86_32 && DISCONTIGMEM
1617
1618 config ARCH_FLATMEM_ENABLE
1619 def_bool y
1620 depends on X86_32 && !NUMA
1621
1622 config ARCH_DISCONTIGMEM_ENABLE
1623 def_bool n
1624 depends on NUMA && X86_32
1625 depends on BROKEN
1626
1627 config ARCH_SPARSEMEM_ENABLE
1628 def_bool y
1629 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1630 select SPARSEMEM_STATIC if X86_32
1631 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1632
1633 config ARCH_SPARSEMEM_DEFAULT
1634 def_bool X86_64 || (NUMA && X86_32)
1635
1636 config ARCH_SELECT_MEMORY_MODEL
1637 def_bool y
1638 depends on ARCH_SPARSEMEM_ENABLE
1639
1640 config ARCH_MEMORY_PROBE
1641 bool "Enable sysfs memory/probe interface"
1642 depends on X86_64 && MEMORY_HOTPLUG
1643 help
1644 This option enables a sysfs memory/probe interface for testing.
1645 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1646 If you are unsure how to answer this question, answer N.
1647
1648 config ARCH_PROC_KCORE_TEXT
1649 def_bool y
1650 depends on X86_64 && PROC_KCORE
1651
1652 config ILLEGAL_POINTER_VALUE
1653 hex
1654 default 0 if X86_32
1655 default 0xdead000000000000 if X86_64
1656
1657 config X86_PMEM_LEGACY_DEVICE
1658 bool
1659
1660 config X86_PMEM_LEGACY
1661 tristate "Support non-standard NVDIMMs and ADR protected memory"
1662 depends on PHYS_ADDR_T_64BIT
1663 depends on BLK_DEV
1664 select X86_PMEM_LEGACY_DEVICE
1665 select NUMA_KEEP_MEMINFO if NUMA
1666 select LIBNVDIMM
1667 help
1668 Treat memory marked using the non-standard e820 type of 12 as used
1669 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1670 The kernel will offer these regions to the 'pmem' driver so
1671 they can be used for persistent storage.
1672
1673 Say Y if unsure.
1674
1675 config HIGHPTE
1676 bool "Allocate 3rd-level pagetables from highmem"
1677 depends on HIGHMEM
1678 ---help---
1679 The VM uses one page table entry for each page of physical memory.
1680 For systems with a lot of RAM, this can be wasteful of precious
1681 low memory. Setting this option will put user-space page table
1682 entries in high memory.
1683
1684 config X86_CHECK_BIOS_CORRUPTION
1685 bool "Check for low memory corruption"
1686 ---help---
1687 Periodically check for memory corruption in low memory, which
1688 is suspected to be caused by BIOS. Even when enabled in the
1689 configuration, it is disabled at runtime. Enable it by
1690 setting "memory_corruption_check=1" on the kernel command
1691 line. By default it scans the low 64k of memory every 60
1692 seconds; see the memory_corruption_check_size and
1693 memory_corruption_check_period parameters in
1694 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1695
1696 When enabled with the default parameters, this option has
1697 almost no overhead, as it reserves a relatively small amount
1698 of memory and scans it infrequently. It both detects corruption
1699 and prevents it from affecting the running system.
1700
1701 It is, however, intended as a diagnostic tool; if repeatable
1702 BIOS-originated corruption always affects the same memory,
1703 you can use memmap= to prevent the kernel from using that
1704 memory.
1705
1706 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1707 bool "Set the default setting of memory_corruption_check"
1708 depends on X86_CHECK_BIOS_CORRUPTION
1709 default y
1710 ---help---
1711 Set whether the default state of memory_corruption_check is
1712 on or off.
1713
1714 config X86_RESERVE_LOW
1715 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1716 default 64
1717 range 4 640
1718 ---help---
1719 Specify the amount of low memory to reserve for the BIOS.
1720
1721 The first page contains BIOS data structures that the kernel
1722 must not use, so that page must always be reserved.
1723
1724 By default we reserve the first 64K of physical RAM, as a
1725 number of BIOSes are known to corrupt that memory range
1726 during events such as suspend/resume or monitor cable
1727 insertion, so it must not be used by the kernel.
1728
1729 You can set this to 4 if you are absolutely sure that you
1730 trust the BIOS to get all its memory reservations and usages
1731 right. If you know your BIOS have problems beyond the
1732 default 64K area, you can set this to 640 to avoid using the
1733 entire low memory range.
1734
1735 If you have doubts about the BIOS (e.g. suspend/resume does
1736 not work or there's kernel crashes after certain hardware
1737 hotplug events) then you might want to enable
1738 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1739 typical corruption patterns.
1740
1741 Leave this to the default value of 64 if you are unsure.
1742
1743 config MATH_EMULATION
1744 bool
1745 depends on MODIFY_LDT_SYSCALL
1746 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1747 ---help---
1748 Linux can emulate a math coprocessor (used for floating point
1749 operations) if you don't have one. 486DX and Pentium processors have
1750 a math coprocessor built in, 486SX and 386 do not, unless you added
1751 a 487DX or 387, respectively. (The messages during boot time can
1752 give you some hints here ["man dmesg"].) Everyone needs either a
1753 coprocessor or this emulation.
1754
1755 If you don't have a math coprocessor, you need to say Y here; if you
1756 say Y here even though you have a coprocessor, the coprocessor will
1757 be used nevertheless. (This behavior can be changed with the kernel
1758 command line option "no387", which comes handy if your coprocessor
1759 is broken. Try "man bootparam" or see the documentation of your boot
1760 loader (lilo or loadlin) about how to pass options to the kernel at
1761 boot time.) This means that it is a good idea to say Y here if you
1762 intend to use this kernel on different machines.
1763
1764 More information about the internals of the Linux math coprocessor
1765 emulation can be found in <file:arch/x86/math-emu/README>.
1766
1767 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1768 kernel, it won't hurt.
1769
1770 config MTRR
1771 def_bool y
1772 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1773 ---help---
1774 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1775 the Memory Type Range Registers (MTRRs) may be used to control
1776 processor access to memory ranges. This is most useful if you have
1777 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1778 allows bus write transfers to be combined into a larger transfer
1779 before bursting over the PCI/AGP bus. This can increase performance
1780 of image write operations 2.5 times or more. Saying Y here creates a
1781 /proc/mtrr file which may be used to manipulate your processor's
1782 MTRRs. Typically the X server should use this.
1783
1784 This code has a reasonably generic interface so that similar
1785 control registers on other processors can be easily supported
1786 as well:
1787
1788 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1789 Registers (ARRs) which provide a similar functionality to MTRRs. For
1790 these, the ARRs are used to emulate the MTRRs.
1791 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1792 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1793 write-combining. All of these processors are supported by this code
1794 and it makes sense to say Y here if you have one of them.
1795
1796 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1797 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1798 can lead to all sorts of problems, so it's good to say Y here.
1799
1800 You can safely say Y even if your machine doesn't have MTRRs, you'll
1801 just add about 9 KB to your kernel.
1802
1803 See <file:Documentation/x86/mtrr.rst> for more information.
1804
1805 config MTRR_SANITIZER
1806 def_bool y
1807 prompt "MTRR cleanup support"
1808 depends on MTRR
1809 ---help---
1810 Convert MTRR layout from continuous to discrete, so X drivers can
1811 add writeback entries.
1812
1813 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1814 The largest mtrr entry size for a continuous block can be set with
1815 mtrr_chunk_size.
1816
1817 If unsure, say Y.
1818
1819 config MTRR_SANITIZER_ENABLE_DEFAULT
1820 int "MTRR cleanup enable value (0-1)"
1821 range 0 1
1822 default "0"
1823 depends on MTRR_SANITIZER
1824 ---help---
1825 Enable mtrr cleanup default value
1826
1827 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1828 int "MTRR cleanup spare reg num (0-7)"
1829 range 0 7
1830 default "1"
1831 depends on MTRR_SANITIZER
1832 ---help---
1833 mtrr cleanup spare entries default, it can be changed via
1834 mtrr_spare_reg_nr=N on the kernel command line.
1835
1836 config X86_PAT
1837 def_bool y
1838 prompt "x86 PAT support" if EXPERT
1839 depends on MTRR
1840 ---help---
1841 Use PAT attributes to setup page level cache control.
1842
1843 PATs are the modern equivalents of MTRRs and are much more
1844 flexible than MTRRs.
1845
1846 Say N here if you see bootup problems (boot crash, boot hang,
1847 spontaneous reboots) or a non-working video driver.
1848
1849 If unsure, say Y.
1850
1851 config ARCH_USES_PG_UNCACHED
1852 def_bool y
1853 depends on X86_PAT
1854
1855 config ARCH_RANDOM
1856 def_bool y
1857 prompt "x86 architectural random number generator" if EXPERT
1858 ---help---
1859 Enable the x86 architectural RDRAND instruction
1860 (Intel Bull Mountain technology) to generate random numbers.
1861 If supported, this is a high bandwidth, cryptographically
1862 secure hardware random number generator.
1863
1864 config X86_SMAP
1865 def_bool y
1866 prompt "Supervisor Mode Access Prevention" if EXPERT
1867 ---help---
1868 Supervisor Mode Access Prevention (SMAP) is a security
1869 feature in newer Intel processors. There is a small
1870 performance cost if this enabled and turned on; there is
1871 also a small increase in the kernel size if this is enabled.
1872
1873 If unsure, say Y.
1874
1875 config X86_UMIP
1876 def_bool y
1877 prompt "User Mode Instruction Prevention" if EXPERT
1878 ---help---
1879 User Mode Instruction Prevention (UMIP) is a security feature in
1880 some x86 processors. If enabled, a general protection fault is
1881 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1882 executed in user mode. These instructions unnecessarily expose
1883 information about the hardware state.
1884
1885 The vast majority of applications do not use these instructions.
1886 For the very few that do, software emulation is provided in
1887 specific cases in protected and virtual-8086 modes. Emulated
1888 results are dummy.
1889
1890 config X86_INTEL_MEMORY_PROTECTION_KEYS
1891 prompt "Intel Memory Protection Keys"
1892 def_bool y
1893 # Note: only available in 64-bit mode
1894 depends on CPU_SUP_INTEL && X86_64
1895 select ARCH_USES_HIGH_VMA_FLAGS
1896 select ARCH_HAS_PKEYS
1897 ---help---
1898 Memory Protection Keys provides a mechanism for enforcing
1899 page-based protections, but without requiring modification of the
1900 page tables when an application changes protection domains.
1901
1902 For details, see Documentation/core-api/protection-keys.rst
1903
1904 If unsure, say y.
1905
1906 choice
1907 prompt "TSX enable mode"
1908 depends on CPU_SUP_INTEL
1909 default X86_INTEL_TSX_MODE_OFF
1910 help
1911 Intel's TSX (Transactional Synchronization Extensions) feature
1912 allows to optimize locking protocols through lock elision which
1913 can lead to a noticeable performance boost.
1914
1915 On the other hand it has been shown that TSX can be exploited
1916 to form side channel attacks (e.g. TAA) and chances are there
1917 will be more of those attacks discovered in the future.
1918
1919 Therefore TSX is not enabled by default (aka tsx=off). An admin
1920 might override this decision by tsx=on the command line parameter.
1921 Even with TSX enabled, the kernel will attempt to enable the best
1922 possible TAA mitigation setting depending on the microcode available
1923 for the particular machine.
1924
1925 This option allows to set the default tsx mode between tsx=on, =off
1926 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1927 details.
1928
1929 Say off if not sure, auto if TSX is in use but it should be used on safe
1930 platforms or on if TSX is in use and the security aspect of tsx is not
1931 relevant.
1932
1933 config X86_INTEL_TSX_MODE_OFF
1934 bool "off"
1935 help
1936 TSX is disabled if possible - equals to tsx=off command line parameter.
1937
1938 config X86_INTEL_TSX_MODE_ON
1939 bool "on"
1940 help
1941 TSX is always enabled on TSX capable HW - equals the tsx=on command
1942 line parameter.
1943
1944 config X86_INTEL_TSX_MODE_AUTO
1945 bool "auto"
1946 help
1947 TSX is enabled on TSX capable HW that is believed to be safe against
1948 side channel attacks- equals the tsx=auto command line parameter.
1949 endchoice
1950
1951 config EFI
1952 bool "EFI runtime service support"
1953 depends on ACPI
1954 select UCS2_STRING
1955 select EFI_RUNTIME_WRAPPERS
1956 ---help---
1957 This enables the kernel to use EFI runtime services that are
1958 available (such as the EFI variable services).
1959
1960 This option is only useful on systems that have EFI firmware.
1961 In addition, you should use the latest ELILO loader available
1962 at <http://elilo.sourceforge.net> in order to take advantage
1963 of EFI runtime services. However, even with this option, the
1964 resultant kernel should continue to boot on existing non-EFI
1965 platforms.
1966
1967 config EFI_STUB
1968 bool "EFI stub support"
1969 depends on EFI && !X86_USE_3DNOW
1970 depends on $(cc-option,-mabi=ms) || X86_32
1971 select RELOCATABLE
1972 ---help---
1973 This kernel feature allows a bzImage to be loaded directly
1974 by EFI firmware without the use of a bootloader.
1975
1976 See Documentation/admin-guide/efi-stub.rst for more information.
1977
1978 config EFI_MIXED
1979 bool "EFI mixed-mode support"
1980 depends on EFI_STUB && X86_64
1981 ---help---
1982 Enabling this feature allows a 64-bit kernel to be booted
1983 on a 32-bit firmware, provided that your CPU supports 64-bit
1984 mode.
1985
1986 Note that it is not possible to boot a mixed-mode enabled
1987 kernel via the EFI boot stub - a bootloader that supports
1988 the EFI handover protocol must be used.
1989
1990 If unsure, say N.
1991
1992 config SECCOMP
1993 def_bool y
1994 prompt "Enable seccomp to safely compute untrusted bytecode"
1995 ---help---
1996 This kernel feature is useful for number crunching applications
1997 that may need to compute untrusted bytecode during their
1998 execution. By using pipes or other transports made available to
1999 the process as file descriptors supporting the read/write
2000 syscalls, it's possible to isolate those applications in
2001 their own address space using seccomp. Once seccomp is
2002 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
2003 and the task is only allowed to execute a few safe syscalls
2004 defined by each seccomp mode.
2005
2006 If unsure, say Y. Only embedded should say N here.
2007
2008 source "kernel/Kconfig.hz"
2009
2010 config KEXEC
2011 bool "kexec system call"
2012 select KEXEC_CORE
2013 ---help---
2014 kexec is a system call that implements the ability to shutdown your
2015 current kernel, and to start another kernel. It is like a reboot
2016 but it is independent of the system firmware. And like a reboot
2017 you can start any kernel with it, not just Linux.
2018
2019 The name comes from the similarity to the exec system call.
2020
2021 It is an ongoing process to be certain the hardware in a machine
2022 is properly shutdown, so do not be surprised if this code does not
2023 initially work for you. As of this writing the exact hardware
2024 interface is strongly in flux, so no good recommendation can be
2025 made.
2026
2027 config KEXEC_FILE
2028 bool "kexec file based system call"
2029 select KEXEC_CORE
2030 select BUILD_BIN2C
2031 depends on X86_64
2032 depends on CRYPTO=y
2033 depends on CRYPTO_SHA256=y
2034 ---help---
2035 This is new version of kexec system call. This system call is
2036 file based and takes file descriptors as system call argument
2037 for kernel and initramfs as opposed to list of segments as
2038 accepted by previous system call.
2039
2040 config ARCH_HAS_KEXEC_PURGATORY
2041 def_bool KEXEC_FILE
2042
2043 config KEXEC_SIG
2044 bool "Verify kernel signature during kexec_file_load() syscall"
2045 depends on KEXEC_FILE
2046 ---help---
2047
2048 This option makes the kexec_file_load() syscall check for a valid
2049 signature of the kernel image. The image can still be loaded without
2050 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2051 there's a signature that we can check, then it must be valid.
2052
2053 In addition to this option, you need to enable signature
2054 verification for the corresponding kernel image type being
2055 loaded in order for this to work.
2056
2057 config KEXEC_SIG_FORCE
2058 bool "Require a valid signature in kexec_file_load() syscall"
2059 depends on KEXEC_SIG
2060 ---help---
2061 This option makes kernel signature verification mandatory for
2062 the kexec_file_load() syscall.
2063
2064 config KEXEC_BZIMAGE_VERIFY_SIG
2065 bool "Enable bzImage signature verification support"
2066 depends on KEXEC_SIG
2067 depends on SIGNED_PE_FILE_VERIFICATION
2068 select SYSTEM_TRUSTED_KEYRING
2069 ---help---
2070 Enable bzImage signature verification support.
2071
2072 config CRASH_DUMP
2073 bool "kernel crash dumps"
2074 depends on X86_64 || (X86_32 && HIGHMEM)
2075 ---help---
2076 Generate crash dump after being started by kexec.
2077 This should be normally only set in special crash dump kernels
2078 which are loaded in the main kernel with kexec-tools into
2079 a specially reserved region and then later executed after
2080 a crash by kdump/kexec. The crash dump kernel must be compiled
2081 to a memory address not used by the main kernel or BIOS using
2082 PHYSICAL_START, or it must be built as a relocatable image
2083 (CONFIG_RELOCATABLE=y).
2084 For more details see Documentation/admin-guide/kdump/kdump.rst
2085
2086 config KEXEC_JUMP
2087 bool "kexec jump"
2088 depends on KEXEC && HIBERNATION
2089 ---help---
2090 Jump between original kernel and kexeced kernel and invoke
2091 code in physical address mode via KEXEC
2092
2093 config PHYSICAL_START
2094 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2095 default "0x1000000"
2096 ---help---
2097 This gives the physical address where the kernel is loaded.
2098
2099 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2100 bzImage will decompress itself to above physical address and
2101 run from there. Otherwise, bzImage will run from the address where
2102 it has been loaded by the boot loader and will ignore above physical
2103 address.
2104
2105 In normal kdump cases one does not have to set/change this option
2106 as now bzImage can be compiled as a completely relocatable image
2107 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2108 address. This option is mainly useful for the folks who don't want
2109 to use a bzImage for capturing the crash dump and want to use a
2110 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2111 to be specifically compiled to run from a specific memory area
2112 (normally a reserved region) and this option comes handy.
2113
2114 So if you are using bzImage for capturing the crash dump,
2115 leave the value here unchanged to 0x1000000 and set
2116 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2117 for capturing the crash dump change this value to start of
2118 the reserved region. In other words, it can be set based on
2119 the "X" value as specified in the "crashkernel=YM@XM"
2120 command line boot parameter passed to the panic-ed
2121 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2122 for more details about crash dumps.
2123
2124 Usage of bzImage for capturing the crash dump is recommended as
2125 one does not have to build two kernels. Same kernel can be used
2126 as production kernel and capture kernel. Above option should have
2127 gone away after relocatable bzImage support is introduced. But it
2128 is present because there are users out there who continue to use
2129 vmlinux for dump capture. This option should go away down the
2130 line.
2131
2132 Don't change this unless you know what you are doing.
2133
2134 config RELOCATABLE
2135 bool "Build a relocatable kernel"
2136 default y
2137 ---help---
2138 This builds a kernel image that retains relocation information
2139 so it can be loaded someplace besides the default 1MB.
2140 The relocations tend to make the kernel binary about 10% larger,
2141 but are discarded at runtime.
2142
2143 One use is for the kexec on panic case where the recovery kernel
2144 must live at a different physical address than the primary
2145 kernel.
2146
2147 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2148 it has been loaded at and the compile time physical address
2149 (CONFIG_PHYSICAL_START) is used as the minimum location.
2150
2151 config RANDOMIZE_BASE
2152 bool "Randomize the address of the kernel image (KASLR)"
2153 depends on RELOCATABLE
2154 default y
2155 ---help---
2156 In support of Kernel Address Space Layout Randomization (KASLR),
2157 this randomizes the physical address at which the kernel image
2158 is decompressed and the virtual address where the kernel
2159 image is mapped, as a security feature that deters exploit
2160 attempts relying on knowledge of the location of kernel
2161 code internals.
2162
2163 On 64-bit, the kernel physical and virtual addresses are
2164 randomized separately. The physical address will be anywhere
2165 between 16MB and the top of physical memory (up to 64TB). The
2166 virtual address will be randomized from 16MB up to 1GB (9 bits
2167 of entropy). Note that this also reduces the memory space
2168 available to kernel modules from 1.5GB to 1GB.
2169
2170 On 32-bit, the kernel physical and virtual addresses are
2171 randomized together. They will be randomized from 16MB up to
2172 512MB (8 bits of entropy).
2173
2174 Entropy is generated using the RDRAND instruction if it is
2175 supported. If RDTSC is supported, its value is mixed into
2176 the entropy pool as well. If neither RDRAND nor RDTSC are
2177 supported, then entropy is read from the i8254 timer. The
2178 usable entropy is limited by the kernel being built using
2179 2GB addressing, and that PHYSICAL_ALIGN must be at a
2180 minimum of 2MB. As a result, only 10 bits of entropy are
2181 theoretically possible, but the implementations are further
2182 limited due to memory layouts.
2183
2184 If unsure, say Y.
2185
2186 # Relocation on x86 needs some additional build support
2187 config X86_NEED_RELOCS
2188 def_bool y
2189 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2190
2191 config PHYSICAL_ALIGN
2192 hex "Alignment value to which kernel should be aligned"
2193 default "0x200000"
2194 range 0x2000 0x1000000 if X86_32
2195 range 0x200000 0x1000000 if X86_64
2196 ---help---
2197 This value puts the alignment restrictions on physical address
2198 where kernel is loaded and run from. Kernel is compiled for an
2199 address which meets above alignment restriction.
2200
2201 If bootloader loads the kernel at a non-aligned address and
2202 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2203 address aligned to above value and run from there.
2204
2205 If bootloader loads the kernel at a non-aligned address and
2206 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2207 load address and decompress itself to the address it has been
2208 compiled for and run from there. The address for which kernel is
2209 compiled already meets above alignment restrictions. Hence the
2210 end result is that kernel runs from a physical address meeting
2211 above alignment restrictions.
2212
2213 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2214 this value must be a multiple of 0x200000.
2215
2216 Don't change this unless you know what you are doing.
2217
2218 config DYNAMIC_MEMORY_LAYOUT
2219 bool
2220 ---help---
2221 This option makes base addresses of vmalloc and vmemmap as well as
2222 __PAGE_OFFSET movable during boot.
2223
2224 config RANDOMIZE_MEMORY
2225 bool "Randomize the kernel memory sections"
2226 depends on X86_64
2227 depends on RANDOMIZE_BASE
2228 select DYNAMIC_MEMORY_LAYOUT
2229 default RANDOMIZE_BASE
2230 ---help---
2231 Randomizes the base virtual address of kernel memory sections
2232 (physical memory mapping, vmalloc & vmemmap). This security feature
2233 makes exploits relying on predictable memory locations less reliable.
2234
2235 The order of allocations remains unchanged. Entropy is generated in
2236 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2237 configuration have in average 30,000 different possible virtual
2238 addresses for each memory section.
2239
2240 If unsure, say Y.
2241
2242 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2243 hex "Physical memory mapping padding" if EXPERT
2244 depends on RANDOMIZE_MEMORY
2245 default "0xa" if MEMORY_HOTPLUG
2246 default "0x0"
2247 range 0x1 0x40 if MEMORY_HOTPLUG
2248 range 0x0 0x40
2249 ---help---
2250 Define the padding in terabytes added to the existing physical
2251 memory size during kernel memory randomization. It is useful
2252 for memory hotplug support but reduces the entropy available for
2253 address randomization.
2254
2255 If unsure, leave at the default value.
2256
2257 config HOTPLUG_CPU
2258 def_bool y
2259 depends on SMP
2260
2261 config BOOTPARAM_HOTPLUG_CPU0
2262 bool "Set default setting of cpu0_hotpluggable"
2263 depends on HOTPLUG_CPU
2264 ---help---
2265 Set whether default state of cpu0_hotpluggable is on or off.
2266
2267 Say Y here to enable CPU0 hotplug by default. If this switch
2268 is turned on, there is no need to give cpu0_hotplug kernel
2269 parameter and the CPU0 hotplug feature is enabled by default.
2270
2271 Please note: there are two known CPU0 dependencies if you want
2272 to enable the CPU0 hotplug feature either by this switch or by
2273 cpu0_hotplug kernel parameter.
2274
2275 First, resume from hibernate or suspend always starts from CPU0.
2276 So hibernate and suspend are prevented if CPU0 is offline.
2277
2278 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2279 offline if any interrupt can not migrate out of CPU0. There may
2280 be other CPU0 dependencies.
2281
2282 Please make sure the dependencies are under your control before
2283 you enable this feature.
2284
2285 Say N if you don't want to enable CPU0 hotplug feature by default.
2286 You still can enable the CPU0 hotplug feature at boot by kernel
2287 parameter cpu0_hotplug.
2288
2289 config DEBUG_HOTPLUG_CPU0
2290 def_bool n
2291 prompt "Debug CPU0 hotplug"
2292 depends on HOTPLUG_CPU
2293 ---help---
2294 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2295 soon as possible and boots up userspace with CPU0 offlined. User
2296 can online CPU0 back after boot time.
2297
2298 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2299 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2300 compilation or giving cpu0_hotplug kernel parameter at boot.
2301
2302 If unsure, say N.
2303
2304 config COMPAT_VDSO
2305 def_bool n
2306 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2307 depends on COMPAT_32
2308 ---help---
2309 Certain buggy versions of glibc will crash if they are
2310 presented with a 32-bit vDSO that is not mapped at the address
2311 indicated in its segment table.
2312
2313 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2314 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2315 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2316 the only released version with the bug, but OpenSUSE 9
2317 contains a buggy "glibc 2.3.2".
2318
2319 The symptom of the bug is that everything crashes on startup, saying:
2320 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2321
2322 Saying Y here changes the default value of the vdso32 boot
2323 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2324 This works around the glibc bug but hurts performance.
2325
2326 If unsure, say N: if you are compiling your own kernel, you
2327 are unlikely to be using a buggy version of glibc.
2328
2329 choice
2330 prompt "vsyscall table for legacy applications"
2331 depends on X86_64
2332 default LEGACY_VSYSCALL_XONLY
2333 help
2334 Legacy user code that does not know how to find the vDSO expects
2335 to be able to issue three syscalls by calling fixed addresses in
2336 kernel space. Since this location is not randomized with ASLR,
2337 it can be used to assist security vulnerability exploitation.
2338
2339 This setting can be changed at boot time via the kernel command
2340 line parameter vsyscall=[emulate|xonly|none].
2341
2342 On a system with recent enough glibc (2.14 or newer) and no
2343 static binaries, you can say None without a performance penalty
2344 to improve security.
2345
2346 If unsure, select "Emulate execution only".
2347
2348 config LEGACY_VSYSCALL_EMULATE
2349 bool "Full emulation"
2350 help
2351 The kernel traps and emulates calls into the fixed vsyscall
2352 address mapping. This makes the mapping non-executable, but
2353 it still contains readable known contents, which could be
2354 used in certain rare security vulnerability exploits. This
2355 configuration is recommended when using legacy userspace
2356 that still uses vsyscalls along with legacy binary
2357 instrumentation tools that require code to be readable.
2358
2359 An example of this type of legacy userspace is running
2360 Pin on an old binary that still uses vsyscalls.
2361
2362 config LEGACY_VSYSCALL_XONLY
2363 bool "Emulate execution only"
2364 help
2365 The kernel traps and emulates calls into the fixed vsyscall
2366 address mapping and does not allow reads. This
2367 configuration is recommended when userspace might use the
2368 legacy vsyscall area but support for legacy binary
2369 instrumentation of legacy code is not needed. It mitigates
2370 certain uses of the vsyscall area as an ASLR-bypassing
2371 buffer.
2372
2373 config LEGACY_VSYSCALL_NONE
2374 bool "None"
2375 help
2376 There will be no vsyscall mapping at all. This will
2377 eliminate any risk of ASLR bypass due to the vsyscall
2378 fixed address mapping. Attempts to use the vsyscalls
2379 will be reported to dmesg, so that either old or
2380 malicious userspace programs can be identified.
2381
2382 endchoice
2383
2384 config CMDLINE_BOOL
2385 bool "Built-in kernel command line"
2386 ---help---
2387 Allow for specifying boot arguments to the kernel at
2388 build time. On some systems (e.g. embedded ones), it is
2389 necessary or convenient to provide some or all of the
2390 kernel boot arguments with the kernel itself (that is,
2391 to not rely on the boot loader to provide them.)
2392
2393 To compile command line arguments into the kernel,
2394 set this option to 'Y', then fill in the
2395 boot arguments in CONFIG_CMDLINE.
2396
2397 Systems with fully functional boot loaders (i.e. non-embedded)
2398 should leave this option set to 'N'.
2399
2400 config CMDLINE
2401 string "Built-in kernel command string"
2402 depends on CMDLINE_BOOL
2403 default ""
2404 ---help---
2405 Enter arguments here that should be compiled into the kernel
2406 image and used at boot time. If the boot loader provides a
2407 command line at boot time, it is appended to this string to
2408 form the full kernel command line, when the system boots.
2409
2410 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2411 change this behavior.
2412
2413 In most cases, the command line (whether built-in or provided
2414 by the boot loader) should specify the device for the root
2415 file system.
2416
2417 config CMDLINE_OVERRIDE
2418 bool "Built-in command line overrides boot loader arguments"
2419 depends on CMDLINE_BOOL && CMDLINE != ""
2420 ---help---
2421 Set this option to 'Y' to have the kernel ignore the boot loader
2422 command line, and use ONLY the built-in command line.
2423
2424 This is used to work around broken boot loaders. This should
2425 be set to 'N' under normal conditions.
2426
2427 config MODIFY_LDT_SYSCALL
2428 bool "Enable the LDT (local descriptor table)" if EXPERT
2429 default y
2430 ---help---
2431 Linux can allow user programs to install a per-process x86
2432 Local Descriptor Table (LDT) using the modify_ldt(2) system
2433 call. This is required to run 16-bit or segmented code such as
2434 DOSEMU or some Wine programs. It is also used by some very old
2435 threading libraries.
2436
2437 Enabling this feature adds a small amount of overhead to
2438 context switches and increases the low-level kernel attack
2439 surface. Disabling it removes the modify_ldt(2) system call.
2440
2441 Saying 'N' here may make sense for embedded or server kernels.
2442
2443 source "kernel/livepatch/Kconfig"
2444
2445 endmenu
2446
2447 config ARCH_HAS_ADD_PAGES
2448 def_bool y
2449 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2450
2451 config ARCH_ENABLE_MEMORY_HOTPLUG
2452 def_bool y
2453 depends on X86_64 || (X86_32 && HIGHMEM)
2454
2455 config ARCH_ENABLE_MEMORY_HOTREMOVE
2456 def_bool y
2457 depends on MEMORY_HOTPLUG
2458
2459 config USE_PERCPU_NUMA_NODE_ID
2460 def_bool y
2461 depends on NUMA
2462
2463 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2464 def_bool y
2465 depends on X86_64 || X86_PAE
2466
2467 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2468 def_bool y
2469 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2470
2471 config ARCH_ENABLE_THP_MIGRATION
2472 def_bool y
2473 depends on X86_64 && TRANSPARENT_HUGEPAGE
2474
2475 menu "Power management and ACPI options"
2476
2477 config ARCH_HIBERNATION_HEADER
2478 def_bool y
2479 depends on HIBERNATION
2480
2481 source "kernel/power/Kconfig"
2482
2483 source "drivers/acpi/Kconfig"
2484
2485 source "drivers/sfi/Kconfig"
2486
2487 config X86_APM_BOOT
2488 def_bool y
2489 depends on APM
2490
2491 menuconfig APM
2492 tristate "APM (Advanced Power Management) BIOS support"
2493 depends on X86_32 && PM_SLEEP
2494 ---help---
2495 APM is a BIOS specification for saving power using several different
2496 techniques. This is mostly useful for battery powered laptops with
2497 APM compliant BIOSes. If you say Y here, the system time will be
2498 reset after a RESUME operation, the /proc/apm device will provide
2499 battery status information, and user-space programs will receive
2500 notification of APM "events" (e.g. battery status change).
2501
2502 If you select "Y" here, you can disable actual use of the APM
2503 BIOS by passing the "apm=off" option to the kernel at boot time.
2504
2505 Note that the APM support is almost completely disabled for
2506 machines with more than one CPU.
2507
2508 In order to use APM, you will need supporting software. For location
2509 and more information, read <file:Documentation/power/apm-acpi.rst>
2510 and the Battery Powered Linux mini-HOWTO, available from
2511 <http://www.tldp.org/docs.html#howto>.
2512
2513 This driver does not spin down disk drives (see the hdparm(8)
2514 manpage ("man 8 hdparm") for that), and it doesn't turn off
2515 VESA-compliant "green" monitors.
2516
2517 This driver does not support the TI 4000M TravelMate and the ACER
2518 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2519 desktop machines also don't have compliant BIOSes, and this driver
2520 may cause those machines to panic during the boot phase.
2521
2522 Generally, if you don't have a battery in your machine, there isn't
2523 much point in using this driver and you should say N. If you get
2524 random kernel OOPSes or reboots that don't seem to be related to
2525 anything, try disabling/enabling this option (or disabling/enabling
2526 APM in your BIOS).
2527
2528 Some other things you should try when experiencing seemingly random,
2529 "weird" problems:
2530
2531 1) make sure that you have enough swap space and that it is
2532 enabled.
2533 2) pass the "no-hlt" option to the kernel
2534 3) switch on floating point emulation in the kernel and pass
2535 the "no387" option to the kernel
2536 4) pass the "floppy=nodma" option to the kernel
2537 5) pass the "mem=4M" option to the kernel (thereby disabling
2538 all but the first 4 MB of RAM)
2539 6) make sure that the CPU is not over clocked.
2540 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2541 8) disable the cache from your BIOS settings
2542 9) install a fan for the video card or exchange video RAM
2543 10) install a better fan for the CPU
2544 11) exchange RAM chips
2545 12) exchange the motherboard.
2546
2547 To compile this driver as a module, choose M here: the
2548 module will be called apm.
2549
2550 if APM
2551
2552 config APM_IGNORE_USER_SUSPEND
2553 bool "Ignore USER SUSPEND"
2554 ---help---
2555 This option will ignore USER SUSPEND requests. On machines with a
2556 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2557 series notebooks, it is necessary to say Y because of a BIOS bug.
2558
2559 config APM_DO_ENABLE
2560 bool "Enable PM at boot time"
2561 ---help---
2562 Enable APM features at boot time. From page 36 of the APM BIOS
2563 specification: "When disabled, the APM BIOS does not automatically
2564 power manage devices, enter the Standby State, enter the Suspend
2565 State, or take power saving steps in response to CPU Idle calls."
2566 This driver will make CPU Idle calls when Linux is idle (unless this
2567 feature is turned off -- see "Do CPU IDLE calls", below). This
2568 should always save battery power, but more complicated APM features
2569 will be dependent on your BIOS implementation. You may need to turn
2570 this option off if your computer hangs at boot time when using APM
2571 support, or if it beeps continuously instead of suspending. Turn
2572 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2573 T400CDT. This is off by default since most machines do fine without
2574 this feature.
2575
2576 config APM_CPU_IDLE
2577 depends on CPU_IDLE
2578 bool "Make CPU Idle calls when idle"
2579 ---help---
2580 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2581 On some machines, this can activate improved power savings, such as
2582 a slowed CPU clock rate, when the machine is idle. These idle calls
2583 are made after the idle loop has run for some length of time (e.g.,
2584 333 mS). On some machines, this will cause a hang at boot time or
2585 whenever the CPU becomes idle. (On machines with more than one CPU,
2586 this option does nothing.)
2587
2588 config APM_DISPLAY_BLANK
2589 bool "Enable console blanking using APM"
2590 ---help---
2591 Enable console blanking using the APM. Some laptops can use this to
2592 turn off the LCD backlight when the screen blanker of the Linux
2593 virtual console blanks the screen. Note that this is only used by
2594 the virtual console screen blanker, and won't turn off the backlight
2595 when using the X Window system. This also doesn't have anything to
2596 do with your VESA-compliant power-saving monitor. Further, this
2597 option doesn't work for all laptops -- it might not turn off your
2598 backlight at all, or it might print a lot of errors to the console,
2599 especially if you are using gpm.
2600
2601 config APM_ALLOW_INTS
2602 bool "Allow interrupts during APM BIOS calls"
2603 ---help---
2604 Normally we disable external interrupts while we are making calls to
2605 the APM BIOS as a measure to lessen the effects of a badly behaving
2606 BIOS implementation. The BIOS should reenable interrupts if it
2607 needs to. Unfortunately, some BIOSes do not -- especially those in
2608 many of the newer IBM Thinkpads. If you experience hangs when you
2609 suspend, try setting this to Y. Otherwise, say N.
2610
2611 endif # APM
2612
2613 source "drivers/cpufreq/Kconfig"
2614
2615 source "drivers/cpuidle/Kconfig"
2616
2617 source "drivers/idle/Kconfig"
2618
2619 endmenu
2620
2621
2622 menu "Bus options (PCI etc.)"
2623
2624 choice
2625 prompt "PCI access mode"
2626 depends on X86_32 && PCI
2627 default PCI_GOANY
2628 ---help---
2629 On PCI systems, the BIOS can be used to detect the PCI devices and
2630 determine their configuration. However, some old PCI motherboards
2631 have BIOS bugs and may crash if this is done. Also, some embedded
2632 PCI-based systems don't have any BIOS at all. Linux can also try to
2633 detect the PCI hardware directly without using the BIOS.
2634
2635 With this option, you can specify how Linux should detect the
2636 PCI devices. If you choose "BIOS", the BIOS will be used,
2637 if you choose "Direct", the BIOS won't be used, and if you
2638 choose "MMConfig", then PCI Express MMCONFIG will be used.
2639 If you choose "Any", the kernel will try MMCONFIG, then the
2640 direct access method and falls back to the BIOS if that doesn't
2641 work. If unsure, go with the default, which is "Any".
2642
2643 config PCI_GOBIOS
2644 bool "BIOS"
2645
2646 config PCI_GOMMCONFIG
2647 bool "MMConfig"
2648
2649 config PCI_GODIRECT
2650 bool "Direct"
2651
2652 config PCI_GOOLPC
2653 bool "OLPC XO-1"
2654 depends on OLPC
2655
2656 config PCI_GOANY
2657 bool "Any"
2658
2659 endchoice
2660
2661 config PCI_BIOS
2662 def_bool y
2663 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2664
2665 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2666 config PCI_DIRECT
2667 def_bool y
2668 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2669
2670 config PCI_MMCONFIG
2671 bool "Support mmconfig PCI config space access" if X86_64
2672 default y
2673 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2674 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2675
2676 config PCI_OLPC
2677 def_bool y
2678 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2679
2680 config PCI_XEN
2681 def_bool y
2682 depends on PCI && XEN
2683 select SWIOTLB_XEN
2684
2685 config MMCONF_FAM10H
2686 def_bool y
2687 depends on X86_64 && PCI_MMCONFIG && ACPI
2688
2689 config PCI_CNB20LE_QUIRK
2690 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2691 depends on PCI
2692 help
2693 Read the PCI windows out of the CNB20LE host bridge. This allows
2694 PCI hotplug to work on systems with the CNB20LE chipset which do
2695 not have ACPI.
2696
2697 There's no public spec for this chipset, and this functionality
2698 is known to be incomplete.
2699
2700 You should say N unless you know you need this.
2701
2702 config ISA_BUS
2703 bool "ISA bus support on modern systems" if EXPERT
2704 help
2705 Expose ISA bus device drivers and options available for selection and
2706 configuration. Enable this option if your target machine has an ISA
2707 bus. ISA is an older system, displaced by PCI and newer bus
2708 architectures -- if your target machine is modern, it probably does
2709 not have an ISA bus.
2710
2711 If unsure, say N.
2712
2713 # x86_64 have no ISA slots, but can have ISA-style DMA.
2714 config ISA_DMA_API
2715 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2716 default y
2717 help
2718 Enables ISA-style DMA support for devices requiring such controllers.
2719 If unsure, say Y.
2720
2721 if X86_32
2722
2723 config ISA
2724 bool "ISA support"
2725 ---help---
2726 Find out whether you have ISA slots on your motherboard. ISA is the
2727 name of a bus system, i.e. the way the CPU talks to the other stuff
2728 inside your box. Other bus systems are PCI, EISA, MicroChannel
2729 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2730 newer boards don't support it. If you have ISA, say Y, otherwise N.
2731
2732 config SCx200
2733 tristate "NatSemi SCx200 support"
2734 ---help---
2735 This provides basic support for National Semiconductor's
2736 (now AMD's) Geode processors. The driver probes for the
2737 PCI-IDs of several on-chip devices, so its a good dependency
2738 for other scx200_* drivers.
2739
2740 If compiled as a module, the driver is named scx200.
2741
2742 config SCx200HR_TIMER
2743 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2744 depends on SCx200
2745 default y
2746 ---help---
2747 This driver provides a clocksource built upon the on-chip
2748 27MHz high-resolution timer. Its also a workaround for
2749 NSC Geode SC-1100's buggy TSC, which loses time when the
2750 processor goes idle (as is done by the scheduler). The
2751 other workaround is idle=poll boot option.
2752
2753 config OLPC
2754 bool "One Laptop Per Child support"
2755 depends on !X86_PAE
2756 select GPIOLIB
2757 select OF
2758 select OF_PROMTREE
2759 select IRQ_DOMAIN
2760 select OLPC_EC
2761 ---help---
2762 Add support for detecting the unique features of the OLPC
2763 XO hardware.
2764
2765 config OLPC_XO1_PM
2766 bool "OLPC XO-1 Power Management"
2767 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2768 ---help---
2769 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2770
2771 config OLPC_XO1_RTC
2772 bool "OLPC XO-1 Real Time Clock"
2773 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2774 ---help---
2775 Add support for the XO-1 real time clock, which can be used as a
2776 programmable wakeup source.
2777
2778 config OLPC_XO1_SCI
2779 bool "OLPC XO-1 SCI extras"
2780 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2781 depends on INPUT=y
2782 select POWER_SUPPLY
2783 ---help---
2784 Add support for SCI-based features of the OLPC XO-1 laptop:
2785 - EC-driven system wakeups
2786 - Power button
2787 - Ebook switch
2788 - Lid switch
2789 - AC adapter status updates
2790 - Battery status updates
2791
2792 config OLPC_XO15_SCI
2793 bool "OLPC XO-1.5 SCI extras"
2794 depends on OLPC && ACPI
2795 select POWER_SUPPLY
2796 ---help---
2797 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2798 - EC-driven system wakeups
2799 - AC adapter status updates
2800 - Battery status updates
2801
2802 config ALIX
2803 bool "PCEngines ALIX System Support (LED setup)"
2804 select GPIOLIB
2805 ---help---
2806 This option enables system support for the PCEngines ALIX.
2807 At present this just sets up LEDs for GPIO control on
2808 ALIX2/3/6 boards. However, other system specific setup should
2809 get added here.
2810
2811 Note: You must still enable the drivers for GPIO and LED support
2812 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2813
2814 Note: You have to set alix.force=1 for boards with Award BIOS.
2815
2816 config NET5501
2817 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2818 select GPIOLIB
2819 ---help---
2820 This option enables system support for the Soekris Engineering net5501.
2821
2822 config GEOS
2823 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2824 select GPIOLIB
2825 depends on DMI
2826 ---help---
2827 This option enables system support for the Traverse Technologies GEOS.
2828
2829 config TS5500
2830 bool "Technologic Systems TS-5500 platform support"
2831 depends on MELAN
2832 select CHECK_SIGNATURE
2833 select NEW_LEDS
2834 select LEDS_CLASS
2835 ---help---
2836 This option enables system support for the Technologic Systems TS-5500.
2837
2838 endif # X86_32
2839
2840 config AMD_NB
2841 def_bool y
2842 depends on CPU_SUP_AMD && PCI
2843
2844 config X86_SYSFB
2845 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2846 help
2847 Firmwares often provide initial graphics framebuffers so the BIOS,
2848 bootloader or kernel can show basic video-output during boot for
2849 user-guidance and debugging. Historically, x86 used the VESA BIOS
2850 Extensions and EFI-framebuffers for this, which are mostly limited
2851 to x86.
2852 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2853 framebuffers so the new generic system-framebuffer drivers can be
2854 used on x86. If the framebuffer is not compatible with the generic
2855 modes, it is advertised as fallback platform framebuffer so legacy
2856 drivers like efifb, vesafb and uvesafb can pick it up.
2857 If this option is not selected, all system framebuffers are always
2858 marked as fallback platform framebuffers as usual.
2859
2860 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2861 not be able to pick up generic system framebuffers if this option
2862 is selected. You are highly encouraged to enable simplefb as
2863 replacement if you select this option. simplefb can correctly deal
2864 with generic system framebuffers. But you should still keep vesafb
2865 and others enabled as fallback if a system framebuffer is
2866 incompatible with simplefb.
2867
2868 If unsure, say Y.
2869
2870 endmenu
2871
2872
2873 menu "Binary Emulations"
2874
2875 config IA32_EMULATION
2876 bool "IA32 Emulation"
2877 depends on X86_64
2878 select ARCH_WANT_OLD_COMPAT_IPC
2879 select BINFMT_ELF
2880 select COMPAT_BINFMT_ELF
2881 select COMPAT_OLD_SIGACTION
2882 ---help---
2883 Include code to run legacy 32-bit programs under a
2884 64-bit kernel. You should likely turn this on, unless you're
2885 100% sure that you don't have any 32-bit programs left.
2886
2887 config IA32_AOUT
2888 tristate "IA32 a.out support"
2889 depends on IA32_EMULATION
2890 depends on BROKEN
2891 ---help---
2892 Support old a.out binaries in the 32bit emulation.
2893
2894 config X86_X32
2895 bool "x32 ABI for 64-bit mode"
2896 depends on X86_64
2897 ---help---
2898 Include code to run binaries for the x32 native 32-bit ABI
2899 for 64-bit processors. An x32 process gets access to the
2900 full 64-bit register file and wide data path while leaving
2901 pointers at 32 bits for smaller memory footprint.
2902
2903 You will need a recent binutils (2.22 or later) with
2904 elf32_x86_64 support enabled to compile a kernel with this
2905 option set.
2906
2907 config COMPAT_32
2908 def_bool y
2909 depends on IA32_EMULATION || X86_32
2910 select HAVE_UID16
2911 select OLD_SIGSUSPEND3
2912
2913 config COMPAT
2914 def_bool y
2915 depends on IA32_EMULATION || X86_X32
2916
2917 if COMPAT
2918 config COMPAT_FOR_U64_ALIGNMENT
2919 def_bool y
2920
2921 config SYSVIPC_COMPAT
2922 def_bool y
2923 depends on SYSVIPC
2924 endif
2925
2926 endmenu
2927
2928
2929 config HAVE_ATOMIC_IOMAP
2930 def_bool y
2931 depends on X86_32
2932
2933 source "drivers/firmware/Kconfig"
2934
2935 source "arch/x86/kvm/Kconfig"
2936
2937 source "arch/x86/Kconfig.assembler"