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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
21 config X86_64
22 def_bool y
23 depends on 64BIT
24 # Options that are inherently 64-bit kernel only:
25 select ARCH_HAS_GIGANTIC_PAGE
26 select ARCH_SUPPORTS_INT128
27 select ARCH_USE_CMPXCHG_LOCKREF
28 select HAVE_ARCH_SOFT_DIRTY
29 select MODULES_USE_ELF_RELA
30 select NEED_DMA_MAP_STATE
31 select SWIOTLB
32 select ARCH_HAS_SYSCALL_WRAPPER
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_DATA
60 select ARCH_CLOCKSOURCE_INIT
61 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
62 select ARCH_HAS_DEBUG_VIRTUAL
63 select ARCH_HAS_DEVMEM_IS_ALLOWED
64 select ARCH_HAS_ELF_RANDOMIZE
65 select ARCH_HAS_FAST_MULTIPLIER
66 select ARCH_HAS_FILTER_PGPROT
67 select ARCH_HAS_FORTIFY_SOURCE
68 select ARCH_HAS_GCOV_PROFILE_ALL
69 select ARCH_HAS_KCOV if X86_64
70 select ARCH_HAS_MEMBARRIER_SYNC_CORE
71 select ARCH_HAS_PMEM_API if X86_64
72 select ARCH_HAS_PTE_SPECIAL
73 select ARCH_HAS_REFCOUNT
74 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
75 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
76 select ARCH_HAS_SET_MEMORY
77 select ARCH_HAS_SET_DIRECT_MAP
78 select ARCH_HAS_STRICT_KERNEL_RWX
79 select ARCH_HAS_STRICT_MODULE_RWX
80 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
81 select ARCH_HAS_UBSAN_SANITIZE_ALL
82 select ARCH_HAS_ZONE_DEVICE if X86_64
83 select ARCH_HAVE_NMI_SAFE_CMPXCHG
84 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
85 select ARCH_MIGHT_HAVE_PC_PARPORT
86 select ARCH_MIGHT_HAVE_PC_SERIO
87 select ARCH_STACKWALK
88 select ARCH_SUPPORTS_ACPI
89 select ARCH_SUPPORTS_ATOMIC_RMW
90 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
91 select ARCH_USE_BUILTIN_BSWAP
92 select ARCH_USE_QUEUED_RWLOCKS
93 select ARCH_USE_QUEUED_SPINLOCKS
94 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
95 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
96 select ARCH_WANTS_THP_SWAP if X86_64
97 select BUILDTIME_EXTABLE_SORT
98 select CLKEVT_I8253
99 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
100 select CLOCKSOURCE_WATCHDOG
101 select DCACHE_WORD_ACCESS
102 select EDAC_ATOMIC_SCRUB
103 select EDAC_SUPPORT
104 select GENERIC_CLOCKEVENTS
105 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
106 select GENERIC_CLOCKEVENTS_MIN_ADJUST
107 select GENERIC_CMOS_UPDATE
108 select GENERIC_CPU_AUTOPROBE
109 select GENERIC_CPU_VULNERABILITIES
110 select GENERIC_EARLY_IOREMAP
111 select GENERIC_FIND_FIRST_BIT
112 select GENERIC_IOMAP
113 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
114 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
115 select GENERIC_IRQ_MIGRATION if SMP
116 select GENERIC_IRQ_PROBE
117 select GENERIC_IRQ_RESERVATION_MODE
118 select GENERIC_IRQ_SHOW
119 select GENERIC_PENDING_IRQ if SMP
120 select GENERIC_SMP_IDLE_THREAD
121 select GENERIC_STRNCPY_FROM_USER
122 select GENERIC_STRNLEN_USER
123 select GENERIC_TIME_VSYSCALL
124 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
125 select HAVE_ACPI_APEI if ACPI
126 select HAVE_ACPI_APEI_NMI if ACPI
127 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
128 select HAVE_ARCH_AUDITSYSCALL
129 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
130 select HAVE_ARCH_JUMP_LABEL
131 select HAVE_ARCH_JUMP_LABEL_RELATIVE
132 select HAVE_ARCH_KASAN if X86_64
133 select HAVE_ARCH_KGDB
134 select HAVE_ARCH_MMAP_RND_BITS if MMU
135 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
136 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
137 select HAVE_ARCH_PREL32_RELOCATIONS
138 select HAVE_ARCH_SECCOMP_FILTER
139 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
140 select HAVE_ARCH_STACKLEAK
141 select HAVE_ARCH_TRACEHOOK
142 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
143 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
144 select HAVE_ARCH_VMAP_STACK if X86_64
145 select HAVE_ARCH_WITHIN_STACK_FRAMES
146 select HAVE_CMPXCHG_DOUBLE
147 select HAVE_CMPXCHG_LOCAL
148 select HAVE_CONTEXT_TRACKING if X86_64
149 select HAVE_COPY_THREAD_TLS
150 select HAVE_C_RECORDMCOUNT
151 select HAVE_DEBUG_KMEMLEAK
152 select HAVE_DMA_CONTIGUOUS
153 select HAVE_DYNAMIC_FTRACE
154 select HAVE_DYNAMIC_FTRACE_WITH_REGS
155 select HAVE_EBPF_JIT
156 select HAVE_EFFICIENT_UNALIGNED_ACCESS
157 select HAVE_EISA
158 select HAVE_EXIT_THREAD
159 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
160 select HAVE_FTRACE_MCOUNT_RECORD
161 select HAVE_FUNCTION_GRAPH_TRACER
162 select HAVE_FUNCTION_TRACER
163 select HAVE_GCC_PLUGINS
164 select HAVE_HW_BREAKPOINT
165 select HAVE_IDE
166 select HAVE_IOREMAP_PROT
167 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
168 select HAVE_IRQ_TIME_ACCOUNTING
169 select HAVE_KERNEL_BZIP2
170 select HAVE_KERNEL_GZIP
171 select HAVE_KERNEL_LZ4
172 select HAVE_KERNEL_LZMA
173 select HAVE_KERNEL_LZO
174 select HAVE_KERNEL_XZ
175 select HAVE_KPROBES
176 select HAVE_KPROBES_ON_FTRACE
177 select HAVE_FUNCTION_ERROR_INJECTION
178 select HAVE_KRETPROBES
179 select HAVE_KVM
180 select HAVE_LIVEPATCH if X86_64
181 select HAVE_MEMBLOCK_NODE_MAP
182 select HAVE_MIXED_BREAKPOINTS_REGS
183 select HAVE_MOD_ARCH_SPECIFIC
184 select HAVE_MOVE_PMD
185 select HAVE_NMI
186 select HAVE_OPROFILE
187 select HAVE_OPTPROBES
188 select HAVE_PCSPKR_PLATFORM
189 select HAVE_PERF_EVENTS
190 select HAVE_PERF_EVENTS_NMI
191 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
192 select HAVE_PCI
193 select HAVE_PERF_REGS
194 select HAVE_PERF_USER_STACK_DUMP
195 select HAVE_RCU_TABLE_FREE if PARAVIRT
196 select HAVE_REGS_AND_STACK_ACCESS_API
197 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
198 select HAVE_FUNCTION_ARG_ACCESS_API
199 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
200 select HAVE_STACK_VALIDATION if X86_64
201 select HAVE_RSEQ
202 select HAVE_SYSCALL_TRACEPOINTS
203 select HAVE_UNSTABLE_SCHED_CLOCK
204 select HAVE_USER_RETURN_NOTIFIER
205 select HOTPLUG_SMT if SMP
206 select IRQ_FORCED_THREADING
207 select NEED_SG_DMA_LENGTH
208 select PCI_DOMAINS if PCI
209 select PCI_LOCKLESS_CONFIG if PCI
210 select PERF_EVENTS
211 select RTC_LIB
212 select RTC_MC146818_LIB
213 select SPARSE_IRQ
214 select SRCU
215 select SYSCTL_EXCEPTION_TRACE
216 select THREAD_INFO_IN_TASK
217 select USER_STACKTRACE_SUPPORT
218 select VIRT_TO_BUS
219 select X86_FEATURE_NAMES if PROC_FS
220
221 config INSTRUCTION_DECODER
222 def_bool y
223 depends on KPROBES || PERF_EVENTS || UPROBES
224
225 config OUTPUT_FORMAT
226 string
227 default "elf32-i386" if X86_32
228 default "elf64-x86-64" if X86_64
229
230 config ARCH_DEFCONFIG
231 string
232 default "arch/x86/configs/i386_defconfig" if X86_32
233 default "arch/x86/configs/x86_64_defconfig" if X86_64
234
235 config LOCKDEP_SUPPORT
236 def_bool y
237
238 config STACKTRACE_SUPPORT
239 def_bool y
240
241 config MMU
242 def_bool y
243
244 config ARCH_MMAP_RND_BITS_MIN
245 default 28 if 64BIT
246 default 8
247
248 config ARCH_MMAP_RND_BITS_MAX
249 default 32 if 64BIT
250 default 16
251
252 config ARCH_MMAP_RND_COMPAT_BITS_MIN
253 default 8
254
255 config ARCH_MMAP_RND_COMPAT_BITS_MAX
256 default 16
257
258 config SBUS
259 bool
260
261 config GENERIC_ISA_DMA
262 def_bool y
263 depends on ISA_DMA_API
264
265 config GENERIC_BUG
266 def_bool y
267 depends on BUG
268 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
269
270 config GENERIC_BUG_RELATIVE_POINTERS
271 bool
272
273 config ARCH_MAY_HAVE_PC_FDC
274 def_bool y
275 depends on ISA_DMA_API
276
277 config GENERIC_CALIBRATE_DELAY
278 def_bool y
279
280 config ARCH_HAS_CPU_RELAX
281 def_bool y
282
283 config ARCH_HAS_CACHE_LINE_SIZE
284 def_bool y
285
286 config ARCH_HAS_FILTER_PGPROT
287 def_bool y
288
289 config HAVE_SETUP_PER_CPU_AREA
290 def_bool y
291
292 config NEED_PER_CPU_EMBED_FIRST_CHUNK
293 def_bool y
294
295 config NEED_PER_CPU_PAGE_FIRST_CHUNK
296 def_bool y
297
298 config ARCH_HIBERNATION_POSSIBLE
299 def_bool y
300
301 config ARCH_SUSPEND_POSSIBLE
302 def_bool y
303
304 config ARCH_WANT_HUGE_PMD_SHARE
305 def_bool y
306
307 config ARCH_WANT_GENERAL_HUGETLB
308 def_bool y
309
310 config ZONE_DMA32
311 def_bool y if X86_64
312
313 config AUDIT_ARCH
314 def_bool y if X86_64
315
316 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
317 def_bool y
318
319 config KASAN_SHADOW_OFFSET
320 hex
321 depends on KASAN
322 default 0xdffffc0000000000
323
324 config HAVE_INTEL_TXT
325 def_bool y
326 depends on INTEL_IOMMU && ACPI
327
328 config X86_32_SMP
329 def_bool y
330 depends on X86_32 && SMP
331
332 config X86_64_SMP
333 def_bool y
334 depends on X86_64 && SMP
335
336 config X86_32_LAZY_GS
337 def_bool y
338 depends on X86_32 && !STACKPROTECTOR
339
340 config ARCH_SUPPORTS_UPROBES
341 def_bool y
342
343 config FIX_EARLYCON_MEM
344 def_bool y
345
346 config DYNAMIC_PHYSICAL_MASK
347 bool
348
349 config PGTABLE_LEVELS
350 int
351 default 5 if X86_5LEVEL
352 default 4 if X86_64
353 default 3 if X86_PAE
354 default 2
355
356 config CC_HAS_SANE_STACKPROTECTOR
357 bool
358 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
359 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
360 help
361 We have to make sure stack protector is unconditionally disabled if
362 the compiler produces broken code.
363
364 menu "Processor type and features"
365
366 config ZONE_DMA
367 bool "DMA memory allocation support" if EXPERT
368 default y
369 help
370 DMA memory allocation support allows devices with less than 32-bit
371 addressing to allocate within the first 16MB of address space.
372 Disable if no such devices will be used.
373
374 If unsure, say Y.
375
376 config SMP
377 bool "Symmetric multi-processing support"
378 ---help---
379 This enables support for systems with more than one CPU. If you have
380 a system with only one CPU, say N. If you have a system with more
381 than one CPU, say Y.
382
383 If you say N here, the kernel will run on uni- and multiprocessor
384 machines, but will use only one CPU of a multiprocessor machine. If
385 you say Y here, the kernel will run on many, but not all,
386 uniprocessor machines. On a uniprocessor machine, the kernel
387 will run faster if you say N here.
388
389 Note that if you say Y here and choose architecture "586" or
390 "Pentium" under "Processor family", the kernel will not work on 486
391 architectures. Similarly, multiprocessor kernels for the "PPro"
392 architecture may not work on all Pentium based boards.
393
394 People using multiprocessor machines who say Y here should also say
395 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
396 Management" code will be disabled if you say Y here.
397
398 See also <file:Documentation/x86/i386/IO-APIC.txt>,
399 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
400 <http://www.tldp.org/docs.html#howto>.
401
402 If you don't know what to do here, say N.
403
404 config X86_FEATURE_NAMES
405 bool "Processor feature human-readable names" if EMBEDDED
406 default y
407 ---help---
408 This option compiles in a table of x86 feature bits and corresponding
409 names. This is required to support /proc/cpuinfo and a few kernel
410 messages. You can disable this to save space, at the expense of
411 making those few kernel messages show numeric feature bits instead.
412
413 If in doubt, say Y.
414
415 config X86_X2APIC
416 bool "Support x2apic"
417 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
418 ---help---
419 This enables x2apic support on CPUs that have this feature.
420
421 This allows 32-bit apic IDs (so it can support very large systems),
422 and accesses the local apic via MSRs not via mmio.
423
424 If you don't know what to do here, say N.
425
426 config X86_MPPARSE
427 bool "Enable MPS table" if ACPI || SFI
428 default y
429 depends on X86_LOCAL_APIC
430 ---help---
431 For old smp systems that do not have proper acpi support. Newer systems
432 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
433
434 config GOLDFISH
435 def_bool y
436 depends on X86_GOLDFISH
437
438 config RETPOLINE
439 bool "Avoid speculative indirect branches in kernel"
440 default y
441 select STACK_VALIDATION if HAVE_STACK_VALIDATION
442 help
443 Compile kernel with the retpoline compiler options to guard against
444 kernel-to-user data leaks by avoiding speculative indirect
445 branches. Requires a compiler with -mindirect-branch=thunk-extern
446 support for full protection. The kernel may run slower.
447
448 config X86_CPU_RESCTRL
449 bool "x86 CPU resource control support"
450 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
451 select KERNFS
452 help
453 Enable x86 CPU resource control support.
454
455 Provide support for the allocation and monitoring of system resources
456 usage by the CPU.
457
458 Intel calls this Intel Resource Director Technology
459 (Intel(R) RDT). More information about RDT can be found in the
460 Intel x86 Architecture Software Developer Manual.
461
462 AMD calls this AMD Platform Quality of Service (AMD QoS).
463 More information about AMD QoS can be found in the AMD64 Technology
464 Platform Quality of Service Extensions manual.
465
466 Say N if unsure.
467
468 if X86_32
469 config X86_BIGSMP
470 bool "Support for big SMP systems with more than 8 CPUs"
471 depends on SMP
472 ---help---
473 This option is needed for the systems that have more than 8 CPUs
474
475 config X86_EXTENDED_PLATFORM
476 bool "Support for extended (non-PC) x86 platforms"
477 default y
478 ---help---
479 If you disable this option then the kernel will only support
480 standard PC platforms. (which covers the vast majority of
481 systems out there.)
482
483 If you enable this option then you'll be able to select support
484 for the following (non-PC) 32 bit x86 platforms:
485 Goldfish (Android emulator)
486 AMD Elan
487 RDC R-321x SoC
488 SGI 320/540 (Visual Workstation)
489 STA2X11-based (e.g. Northville)
490 Moorestown MID devices
491
492 If you have one of these systems, or if you want to build a
493 generic distribution kernel, say Y here - otherwise say N.
494 endif
495
496 if X86_64
497 config X86_EXTENDED_PLATFORM
498 bool "Support for extended (non-PC) x86 platforms"
499 default y
500 ---help---
501 If you disable this option then the kernel will only support
502 standard PC platforms. (which covers the vast majority of
503 systems out there.)
504
505 If you enable this option then you'll be able to select support
506 for the following (non-PC) 64 bit x86 platforms:
507 Numascale NumaChip
508 ScaleMP vSMP
509 SGI Ultraviolet
510
511 If you have one of these systems, or if you want to build a
512 generic distribution kernel, say Y here - otherwise say N.
513 endif
514 # This is an alphabetically sorted list of 64 bit extended platforms
515 # Please maintain the alphabetic order if and when there are additions
516 config X86_NUMACHIP
517 bool "Numascale NumaChip"
518 depends on X86_64
519 depends on X86_EXTENDED_PLATFORM
520 depends on NUMA
521 depends on SMP
522 depends on X86_X2APIC
523 depends on PCI_MMCONFIG
524 ---help---
525 Adds support for Numascale NumaChip large-SMP systems. Needed to
526 enable more than ~168 cores.
527 If you don't have one of these, you should say N here.
528
529 config X86_VSMP
530 bool "ScaleMP vSMP"
531 select HYPERVISOR_GUEST
532 select PARAVIRT
533 depends on X86_64 && PCI
534 depends on X86_EXTENDED_PLATFORM
535 depends on SMP
536 ---help---
537 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
538 supposed to run on these EM64T-based machines. Only choose this option
539 if you have one of these machines.
540
541 config X86_UV
542 bool "SGI Ultraviolet"
543 depends on X86_64
544 depends on X86_EXTENDED_PLATFORM
545 depends on NUMA
546 depends on EFI
547 depends on X86_X2APIC
548 depends on PCI
549 ---help---
550 This option is needed in order to support SGI Ultraviolet systems.
551 If you don't have one of these, you should say N here.
552
553 # Following is an alphabetically sorted list of 32 bit extended platforms
554 # Please maintain the alphabetic order if and when there are additions
555
556 config X86_GOLDFISH
557 bool "Goldfish (Virtual Platform)"
558 depends on X86_EXTENDED_PLATFORM
559 ---help---
560 Enable support for the Goldfish virtual platform used primarily
561 for Android development. Unless you are building for the Android
562 Goldfish emulator say N here.
563
564 config X86_INTEL_CE
565 bool "CE4100 TV platform"
566 depends on PCI
567 depends on PCI_GODIRECT
568 depends on X86_IO_APIC
569 depends on X86_32
570 depends on X86_EXTENDED_PLATFORM
571 select X86_REBOOTFIXUPS
572 select OF
573 select OF_EARLY_FLATTREE
574 ---help---
575 Select for the Intel CE media processor (CE4100) SOC.
576 This option compiles in support for the CE4100 SOC for settop
577 boxes and media devices.
578
579 config X86_INTEL_MID
580 bool "Intel MID platform support"
581 depends on X86_EXTENDED_PLATFORM
582 depends on X86_PLATFORM_DEVICES
583 depends on PCI
584 depends on X86_64 || (PCI_GOANY && X86_32)
585 depends on X86_IO_APIC
586 select SFI
587 select I2C
588 select DW_APB_TIMER
589 select APB_TIMER
590 select INTEL_SCU_IPC
591 select MFD_INTEL_MSIC
592 ---help---
593 Select to build a kernel capable of supporting Intel MID (Mobile
594 Internet Device) platform systems which do not have the PCI legacy
595 interfaces. If you are building for a PC class system say N here.
596
597 Intel MID platforms are based on an Intel processor and chipset which
598 consume less power than most of the x86 derivatives.
599
600 config X86_INTEL_QUARK
601 bool "Intel Quark platform support"
602 depends on X86_32
603 depends on X86_EXTENDED_PLATFORM
604 depends on X86_PLATFORM_DEVICES
605 depends on X86_TSC
606 depends on PCI
607 depends on PCI_GOANY
608 depends on X86_IO_APIC
609 select IOSF_MBI
610 select INTEL_IMR
611 select COMMON_CLK
612 ---help---
613 Select to include support for Quark X1000 SoC.
614 Say Y here if you have a Quark based system such as the Arduino
615 compatible Intel Galileo.
616
617 config X86_INTEL_LPSS
618 bool "Intel Low Power Subsystem Support"
619 depends on X86 && ACPI && PCI
620 select COMMON_CLK
621 select PINCTRL
622 select IOSF_MBI
623 ---help---
624 Select to build support for Intel Low Power Subsystem such as
625 found on Intel Lynxpoint PCH. Selecting this option enables
626 things like clock tree (common clock framework) and pincontrol
627 which are needed by the LPSS peripheral drivers.
628
629 config X86_AMD_PLATFORM_DEVICE
630 bool "AMD ACPI2Platform devices support"
631 depends on ACPI
632 select COMMON_CLK
633 select PINCTRL
634 ---help---
635 Select to interpret AMD specific ACPI device to platform device
636 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
637 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
638 implemented under PINCTRL subsystem.
639
640 config IOSF_MBI
641 tristate "Intel SoC IOSF Sideband support for SoC platforms"
642 depends on PCI
643 ---help---
644 This option enables sideband register access support for Intel SoC
645 platforms. On these platforms the IOSF sideband is used in lieu of
646 MSR's for some register accesses, mostly but not limited to thermal
647 and power. Drivers may query the availability of this device to
648 determine if they need the sideband in order to work on these
649 platforms. The sideband is available on the following SoC products.
650 This list is not meant to be exclusive.
651 - BayTrail
652 - Braswell
653 - Quark
654
655 You should say Y if you are running a kernel on one of these SoC's.
656
657 config IOSF_MBI_DEBUG
658 bool "Enable IOSF sideband access through debugfs"
659 depends on IOSF_MBI && DEBUG_FS
660 ---help---
661 Select this option to expose the IOSF sideband access registers (MCR,
662 MDR, MCRX) through debugfs to write and read register information from
663 different units on the SoC. This is most useful for obtaining device
664 state information for debug and analysis. As this is a general access
665 mechanism, users of this option would have specific knowledge of the
666 device they want to access.
667
668 If you don't require the option or are in doubt, say N.
669
670 config X86_RDC321X
671 bool "RDC R-321x SoC"
672 depends on X86_32
673 depends on X86_EXTENDED_PLATFORM
674 select M486
675 select X86_REBOOTFIXUPS
676 ---help---
677 This option is needed for RDC R-321x system-on-chip, also known
678 as R-8610-(G).
679 If you don't have one of these chips, you should say N here.
680
681 config X86_32_NON_STANDARD
682 bool "Support non-standard 32-bit SMP architectures"
683 depends on X86_32 && SMP
684 depends on X86_EXTENDED_PLATFORM
685 ---help---
686 This option compiles in the bigsmp and STA2X11 default
687 subarchitectures. It is intended for a generic binary
688 kernel. If you select them all, kernel will probe it one by
689 one and will fallback to default.
690
691 # Alphabetically sorted list of Non standard 32 bit platforms
692
693 config X86_SUPPORTS_MEMORY_FAILURE
694 def_bool y
695 # MCE code calls memory_failure():
696 depends on X86_MCE
697 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
698 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
699 depends on X86_64 || !SPARSEMEM
700 select ARCH_SUPPORTS_MEMORY_FAILURE
701
702 config STA2X11
703 bool "STA2X11 Companion Chip Support"
704 depends on X86_32_NON_STANDARD && PCI
705 select ARCH_HAS_PHYS_TO_DMA
706 select SWIOTLB
707 select MFD_STA2X11
708 select GPIOLIB
709 ---help---
710 This adds support for boards based on the STA2X11 IO-Hub,
711 a.k.a. "ConneXt". The chip is used in place of the standard
712 PC chipset, so all "standard" peripherals are missing. If this
713 option is selected the kernel will still be able to boot on
714 standard PC machines.
715
716 config X86_32_IRIS
717 tristate "Eurobraille/Iris poweroff module"
718 depends on X86_32
719 ---help---
720 The Iris machines from EuroBraille do not have APM or ACPI support
721 to shut themselves down properly. A special I/O sequence is
722 needed to do so, which is what this module does at
723 kernel shutdown.
724
725 This is only for Iris machines from EuroBraille.
726
727 If unused, say N.
728
729 config SCHED_OMIT_FRAME_POINTER
730 def_bool y
731 prompt "Single-depth WCHAN output"
732 depends on X86
733 ---help---
734 Calculate simpler /proc/<PID>/wchan values. If this option
735 is disabled then wchan values will recurse back to the
736 caller function. This provides more accurate wchan values,
737 at the expense of slightly more scheduling overhead.
738
739 If in doubt, say "Y".
740
741 menuconfig HYPERVISOR_GUEST
742 bool "Linux guest support"
743 ---help---
744 Say Y here to enable options for running Linux under various hyper-
745 visors. This option enables basic hypervisor detection and platform
746 setup.
747
748 If you say N, all options in this submenu will be skipped and
749 disabled, and Linux guest support won't be built in.
750
751 if HYPERVISOR_GUEST
752
753 config PARAVIRT
754 bool "Enable paravirtualization code"
755 ---help---
756 This changes the kernel so it can modify itself when it is run
757 under a hypervisor, potentially improving performance significantly
758 over full virtualization. However, when run without a hypervisor
759 the kernel is theoretically slower and slightly larger.
760
761 config PARAVIRT_XXL
762 bool
763
764 config PARAVIRT_DEBUG
765 bool "paravirt-ops debugging"
766 depends on PARAVIRT && DEBUG_KERNEL
767 ---help---
768 Enable to debug paravirt_ops internals. Specifically, BUG if
769 a paravirt_op is missing when it is called.
770
771 config PARAVIRT_SPINLOCKS
772 bool "Paravirtualization layer for spinlocks"
773 depends on PARAVIRT && SMP
774 ---help---
775 Paravirtualized spinlocks allow a pvops backend to replace the
776 spinlock implementation with something virtualization-friendly
777 (for example, block the virtual CPU rather than spinning).
778
779 It has a minimal impact on native kernels and gives a nice performance
780 benefit on paravirtualized KVM / Xen kernels.
781
782 If you are unsure how to answer this question, answer Y.
783
784 source "arch/x86/xen/Kconfig"
785
786 config KVM_GUEST
787 bool "KVM Guest support (including kvmclock)"
788 depends on PARAVIRT
789 select PARAVIRT_CLOCK
790 default y
791 ---help---
792 This option enables various optimizations for running under the KVM
793 hypervisor. It includes a paravirtualized clock, so that instead
794 of relying on a PIT (or probably other) emulation by the
795 underlying device model, the host provides the guest with
796 timing infrastructure such as time of day, and system time
797
798 config PVH
799 bool "Support for running PVH guests"
800 ---help---
801 This option enables the PVH entry point for guest virtual machines
802 as specified in the x86/HVM direct boot ABI.
803
804 config KVM_DEBUG_FS
805 bool "Enable debug information for KVM Guests in debugfs"
806 depends on KVM_GUEST && DEBUG_FS
807 ---help---
808 This option enables collection of various statistics for KVM guest.
809 Statistics are displayed in debugfs filesystem. Enabling this option
810 may incur significant overhead.
811
812 config PARAVIRT_TIME_ACCOUNTING
813 bool "Paravirtual steal time accounting"
814 depends on PARAVIRT
815 ---help---
816 Select this option to enable fine granularity task steal time
817 accounting. Time spent executing other tasks in parallel with
818 the current vCPU is discounted from the vCPU power. To account for
819 that, there can be a small performance impact.
820
821 If in doubt, say N here.
822
823 config PARAVIRT_CLOCK
824 bool
825
826 config JAILHOUSE_GUEST
827 bool "Jailhouse non-root cell support"
828 depends on X86_64 && PCI
829 select X86_PM_TIMER
830 ---help---
831 This option allows to run Linux as guest in a Jailhouse non-root
832 cell. You can leave this option disabled if you only want to start
833 Jailhouse and run Linux afterwards in the root cell.
834
835 endif #HYPERVISOR_GUEST
836
837 source "arch/x86/Kconfig.cpu"
838
839 config HPET_TIMER
840 def_bool X86_64
841 prompt "HPET Timer Support" if X86_32
842 ---help---
843 Use the IA-PC HPET (High Precision Event Timer) to manage
844 time in preference to the PIT and RTC, if a HPET is
845 present.
846 HPET is the next generation timer replacing legacy 8254s.
847 The HPET provides a stable time base on SMP
848 systems, unlike the TSC, but it is more expensive to access,
849 as it is off-chip. The interface used is documented
850 in the HPET spec, revision 1.
851
852 You can safely choose Y here. However, HPET will only be
853 activated if the platform and the BIOS support this feature.
854 Otherwise the 8254 will be used for timing services.
855
856 Choose N to continue using the legacy 8254 timer.
857
858 config HPET_EMULATE_RTC
859 def_bool y
860 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
861
862 config APB_TIMER
863 def_bool y if X86_INTEL_MID
864 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
865 select DW_APB_TIMER
866 depends on X86_INTEL_MID && SFI
867 help
868 APB timer is the replacement for 8254, HPET on X86 MID platforms.
869 The APBT provides a stable time base on SMP
870 systems, unlike the TSC, but it is more expensive to access,
871 as it is off-chip. APB timers are always running regardless of CPU
872 C states, they are used as per CPU clockevent device when possible.
873
874 # Mark as expert because too many people got it wrong.
875 # The code disables itself when not needed.
876 config DMI
877 default y
878 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
879 bool "Enable DMI scanning" if EXPERT
880 ---help---
881 Enabled scanning of DMI to identify machine quirks. Say Y
882 here unless you have verified that your setup is not
883 affected by entries in the DMI blacklist. Required by PNP
884 BIOS code.
885
886 config GART_IOMMU
887 bool "Old AMD GART IOMMU support"
888 select IOMMU_HELPER
889 select SWIOTLB
890 depends on X86_64 && PCI && AMD_NB
891 ---help---
892 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
893 GART based hardware IOMMUs.
894
895 The GART supports full DMA access for devices with 32-bit access
896 limitations, on systems with more than 3 GB. This is usually needed
897 for USB, sound, many IDE/SATA chipsets and some other devices.
898
899 Newer systems typically have a modern AMD IOMMU, supported via
900 the CONFIG_AMD_IOMMU=y config option.
901
902 In normal configurations this driver is only active when needed:
903 there's more than 3 GB of memory and the system contains a
904 32-bit limited device.
905
906 If unsure, say Y.
907
908 config CALGARY_IOMMU
909 bool "IBM Calgary IOMMU support"
910 select IOMMU_HELPER
911 select SWIOTLB
912 depends on X86_64 && PCI
913 ---help---
914 Support for hardware IOMMUs in IBM's xSeries x366 and x460
915 systems. Needed to run systems with more than 3GB of memory
916 properly with 32-bit PCI devices that do not support DAC
917 (Double Address Cycle). Calgary also supports bus level
918 isolation, where all DMAs pass through the IOMMU. This
919 prevents them from going anywhere except their intended
920 destination. This catches hard-to-find kernel bugs and
921 mis-behaving drivers and devices that do not use the DMA-API
922 properly to set up their DMA buffers. The IOMMU can be
923 turned off at boot time with the iommu=off parameter.
924 Normally the kernel will make the right choice by itself.
925 If unsure, say Y.
926
927 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
928 def_bool y
929 prompt "Should Calgary be enabled by default?"
930 depends on CALGARY_IOMMU
931 ---help---
932 Should Calgary be enabled by default? if you choose 'y', Calgary
933 will be used (if it exists). If you choose 'n', Calgary will not be
934 used even if it exists. If you choose 'n' and would like to use
935 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
936 If unsure, say Y.
937
938 config MAXSMP
939 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
940 depends on X86_64 && SMP && DEBUG_KERNEL
941 select CPUMASK_OFFSTACK
942 ---help---
943 Enable maximum number of CPUS and NUMA Nodes for this architecture.
944 If unsure, say N.
945
946 #
947 # The maximum number of CPUs supported:
948 #
949 # The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
950 # and which can be configured interactively in the
951 # [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
952 #
953 # The ranges are different on 32-bit and 64-bit kernels, depending on
954 # hardware capabilities and scalability features of the kernel.
955 #
956 # ( If MAXSMP is enabled we just use the highest possible value and disable
957 # interactive configuration. )
958 #
959
960 config NR_CPUS_RANGE_BEGIN
961 int
962 default NR_CPUS_RANGE_END if MAXSMP
963 default 1 if !SMP
964 default 2
965
966 config NR_CPUS_RANGE_END
967 int
968 depends on X86_32
969 default 64 if SMP && X86_BIGSMP
970 default 8 if SMP && !X86_BIGSMP
971 default 1 if !SMP
972
973 config NR_CPUS_RANGE_END
974 int
975 depends on X86_64
976 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK)
977 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
978 default 1 if !SMP
979
980 config NR_CPUS_DEFAULT
981 int
982 depends on X86_32
983 default 32 if X86_BIGSMP
984 default 8 if SMP
985 default 1 if !SMP
986
987 config NR_CPUS_DEFAULT
988 int
989 depends on X86_64
990 default 8192 if MAXSMP
991 default 64 if SMP
992 default 1 if !SMP
993
994 config NR_CPUS
995 int "Maximum number of CPUs" if SMP && !MAXSMP
996 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
997 default NR_CPUS_DEFAULT
998 ---help---
999 This allows you to specify the maximum number of CPUs which this
1000 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
1001 supported value is 8192, otherwise the maximum value is 512. The
1002 minimum value which makes sense is 2.
1003
1004 This is purely to save memory: each supported CPU adds about 8KB
1005 to the kernel image.
1006
1007 config SCHED_SMT
1008 def_bool y if SMP
1009
1010 config SCHED_MC
1011 def_bool y
1012 prompt "Multi-core scheduler support"
1013 depends on SMP
1014 ---help---
1015 Multi-core scheduler support improves the CPU scheduler's decision
1016 making when dealing with multi-core CPU chips at a cost of slightly
1017 increased overhead in some places. If unsure say N here.
1018
1019 config SCHED_MC_PRIO
1020 bool "CPU core priorities scheduler support"
1021 depends on SCHED_MC && CPU_SUP_INTEL
1022 select X86_INTEL_PSTATE
1023 select CPU_FREQ
1024 default y
1025 ---help---
1026 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1027 core ordering determined at manufacturing time, which allows
1028 certain cores to reach higher turbo frequencies (when running
1029 single threaded workloads) than others.
1030
1031 Enabling this kernel feature teaches the scheduler about
1032 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1033 scheduler's CPU selection logic accordingly, so that higher
1034 overall system performance can be achieved.
1035
1036 This feature will have no effect on CPUs without this feature.
1037
1038 If unsure say Y here.
1039
1040 config UP_LATE_INIT
1041 def_bool y
1042 depends on !SMP && X86_LOCAL_APIC
1043
1044 config X86_UP_APIC
1045 bool "Local APIC support on uniprocessors" if !PCI_MSI
1046 default PCI_MSI
1047 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1048 ---help---
1049 A local APIC (Advanced Programmable Interrupt Controller) is an
1050 integrated interrupt controller in the CPU. If you have a single-CPU
1051 system which has a processor with a local APIC, you can say Y here to
1052 enable and use it. If you say Y here even though your machine doesn't
1053 have a local APIC, then the kernel will still run with no slowdown at
1054 all. The local APIC supports CPU-generated self-interrupts (timer,
1055 performance counters), and the NMI watchdog which detects hard
1056 lockups.
1057
1058 config X86_UP_IOAPIC
1059 bool "IO-APIC support on uniprocessors"
1060 depends on X86_UP_APIC
1061 ---help---
1062 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1063 SMP-capable replacement for PC-style interrupt controllers. Most
1064 SMP systems and many recent uniprocessor systems have one.
1065
1066 If you have a single-CPU system with an IO-APIC, you can say Y here
1067 to use it. If you say Y here even though your machine doesn't have
1068 an IO-APIC, then the kernel will still run with no slowdown at all.
1069
1070 config X86_LOCAL_APIC
1071 def_bool y
1072 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1073 select IRQ_DOMAIN_HIERARCHY
1074 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1075
1076 config X86_IO_APIC
1077 def_bool y
1078 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1079
1080 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1081 bool "Reroute for broken boot IRQs"
1082 depends on X86_IO_APIC
1083 ---help---
1084 This option enables a workaround that fixes a source of
1085 spurious interrupts. This is recommended when threaded
1086 interrupt handling is used on systems where the generation of
1087 superfluous "boot interrupts" cannot be disabled.
1088
1089 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1090 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1091 kernel does during interrupt handling). On chipsets where this
1092 boot IRQ generation cannot be disabled, this workaround keeps
1093 the original IRQ line masked so that only the equivalent "boot
1094 IRQ" is delivered to the CPUs. The workaround also tells the
1095 kernel to set up the IRQ handler on the boot IRQ line. In this
1096 way only one interrupt is delivered to the kernel. Otherwise
1097 the spurious second interrupt may cause the kernel to bring
1098 down (vital) interrupt lines.
1099
1100 Only affects "broken" chipsets. Interrupt sharing may be
1101 increased on these systems.
1102
1103 config X86_MCE
1104 bool "Machine Check / overheating reporting"
1105 select GENERIC_ALLOCATOR
1106 default y
1107 ---help---
1108 Machine Check support allows the processor to notify the
1109 kernel if it detects a problem (e.g. overheating, data corruption).
1110 The action the kernel takes depends on the severity of the problem,
1111 ranging from warning messages to halting the machine.
1112
1113 config X86_MCELOG_LEGACY
1114 bool "Support for deprecated /dev/mcelog character device"
1115 depends on X86_MCE
1116 ---help---
1117 Enable support for /dev/mcelog which is needed by the old mcelog
1118 userspace logging daemon. Consider switching to the new generation
1119 rasdaemon solution.
1120
1121 config X86_MCE_INTEL
1122 def_bool y
1123 prompt "Intel MCE features"
1124 depends on X86_MCE && X86_LOCAL_APIC
1125 ---help---
1126 Additional support for intel specific MCE features such as
1127 the thermal monitor.
1128
1129 config X86_MCE_AMD
1130 def_bool y
1131 prompt "AMD MCE features"
1132 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1133 ---help---
1134 Additional support for AMD specific MCE features such as
1135 the DRAM Error Threshold.
1136
1137 config X86_ANCIENT_MCE
1138 bool "Support for old Pentium 5 / WinChip machine checks"
1139 depends on X86_32 && X86_MCE
1140 ---help---
1141 Include support for machine check handling on old Pentium 5 or WinChip
1142 systems. These typically need to be enabled explicitly on the command
1143 line.
1144
1145 config X86_MCE_THRESHOLD
1146 depends on X86_MCE_AMD || X86_MCE_INTEL
1147 def_bool y
1148
1149 config X86_MCE_INJECT
1150 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1151 tristate "Machine check injector support"
1152 ---help---
1153 Provide support for injecting machine checks for testing purposes.
1154 If you don't know what a machine check is and you don't do kernel
1155 QA it is safe to say n.
1156
1157 config X86_THERMAL_VECTOR
1158 def_bool y
1159 depends on X86_MCE_INTEL
1160
1161 source "arch/x86/events/Kconfig"
1162
1163 config X86_LEGACY_VM86
1164 bool "Legacy VM86 support"
1165 depends on X86_32
1166 ---help---
1167 This option allows user programs to put the CPU into V8086
1168 mode, which is an 80286-era approximation of 16-bit real mode.
1169
1170 Some very old versions of X and/or vbetool require this option
1171 for user mode setting. Similarly, DOSEMU will use it if
1172 available to accelerate real mode DOS programs. However, any
1173 recent version of DOSEMU, X, or vbetool should be fully
1174 functional even without kernel VM86 support, as they will all
1175 fall back to software emulation. Nevertheless, if you are using
1176 a 16-bit DOS program where 16-bit performance matters, vm86
1177 mode might be faster than emulation and you might want to
1178 enable this option.
1179
1180 Note that any app that works on a 64-bit kernel is unlikely to
1181 need this option, as 64-bit kernels don't, and can't, support
1182 V8086 mode. This option is also unrelated to 16-bit protected
1183 mode and is not needed to run most 16-bit programs under Wine.
1184
1185 Enabling this option increases the complexity of the kernel
1186 and slows down exception handling a tiny bit.
1187
1188 If unsure, say N here.
1189
1190 config VM86
1191 bool
1192 default X86_LEGACY_VM86
1193
1194 config X86_16BIT
1195 bool "Enable support for 16-bit segments" if EXPERT
1196 default y
1197 depends on MODIFY_LDT_SYSCALL
1198 ---help---
1199 This option is required by programs like Wine to run 16-bit
1200 protected mode legacy code on x86 processors. Disabling
1201 this option saves about 300 bytes on i386, or around 6K text
1202 plus 16K runtime memory on x86-64,
1203
1204 config X86_ESPFIX32
1205 def_bool y
1206 depends on X86_16BIT && X86_32
1207
1208 config X86_ESPFIX64
1209 def_bool y
1210 depends on X86_16BIT && X86_64
1211
1212 config X86_VSYSCALL_EMULATION
1213 bool "Enable vsyscall emulation" if EXPERT
1214 default y
1215 depends on X86_64
1216 ---help---
1217 This enables emulation of the legacy vsyscall page. Disabling
1218 it is roughly equivalent to booting with vsyscall=none, except
1219 that it will also disable the helpful warning if a program
1220 tries to use a vsyscall. With this option set to N, offending
1221 programs will just segfault, citing addresses of the form
1222 0xffffffffff600?00.
1223
1224 This option is required by many programs built before 2013, and
1225 care should be used even with newer programs if set to N.
1226
1227 Disabling this option saves about 7K of kernel size and
1228 possibly 4K of additional runtime pagetable memory.
1229
1230 config TOSHIBA
1231 tristate "Toshiba Laptop support"
1232 depends on X86_32
1233 ---help---
1234 This adds a driver to safely access the System Management Mode of
1235 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1236 not work on models with a Phoenix BIOS. The System Management Mode
1237 is used to set the BIOS and power saving options on Toshiba portables.
1238
1239 For information on utilities to make use of this driver see the
1240 Toshiba Linux utilities web site at:
1241 <http://www.buzzard.org.uk/toshiba/>.
1242
1243 Say Y if you intend to run this kernel on a Toshiba portable.
1244 Say N otherwise.
1245
1246 config I8K
1247 tristate "Dell i8k legacy laptop support"
1248 select HWMON
1249 select SENSORS_DELL_SMM
1250 ---help---
1251 This option enables legacy /proc/i8k userspace interface in hwmon
1252 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1253 temperature and allows controlling fan speeds of Dell laptops via
1254 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1255 it reports also power and hotkey status. For fan speed control is
1256 needed userspace package i8kutils.
1257
1258 Say Y if you intend to run this kernel on old Dell laptops or want to
1259 use userspace package i8kutils.
1260 Say N otherwise.
1261
1262 config X86_REBOOTFIXUPS
1263 bool "Enable X86 board specific fixups for reboot"
1264 depends on X86_32
1265 ---help---
1266 This enables chipset and/or board specific fixups to be done
1267 in order to get reboot to work correctly. This is only needed on
1268 some combinations of hardware and BIOS. The symptom, for which
1269 this config is intended, is when reboot ends with a stalled/hung
1270 system.
1271
1272 Currently, the only fixup is for the Geode machines using
1273 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1274
1275 Say Y if you want to enable the fixup. Currently, it's safe to
1276 enable this option even if you don't need it.
1277 Say N otherwise.
1278
1279 config MICROCODE
1280 bool "CPU microcode loading support"
1281 default y
1282 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1283 select FW_LOADER
1284 ---help---
1285 If you say Y here, you will be able to update the microcode on
1286 Intel and AMD processors. The Intel support is for the IA32 family,
1287 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1288 AMD support is for families 0x10 and later. You will obviously need
1289 the actual microcode binary data itself which is not shipped with
1290 the Linux kernel.
1291
1292 The preferred method to load microcode from a detached initrd is described
1293 in Documentation/x86/microcode.txt. For that you need to enable
1294 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1295 initrd for microcode blobs.
1296
1297 In addition, you can build the microcode into the kernel. For that you
1298 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1299 config option.
1300
1301 config MICROCODE_INTEL
1302 bool "Intel microcode loading support"
1303 depends on MICROCODE
1304 default MICROCODE
1305 select FW_LOADER
1306 ---help---
1307 This options enables microcode patch loading support for Intel
1308 processors.
1309
1310 For the current Intel microcode data package go to
1311 <https://downloadcenter.intel.com> and search for
1312 'Linux Processor Microcode Data File'.
1313
1314 config MICROCODE_AMD
1315 bool "AMD microcode loading support"
1316 depends on MICROCODE
1317 select FW_LOADER
1318 ---help---
1319 If you select this option, microcode patch loading support for AMD
1320 processors will be enabled.
1321
1322 config MICROCODE_OLD_INTERFACE
1323 bool "Ancient loading interface (DEPRECATED)"
1324 default n
1325 depends on MICROCODE
1326 ---help---
1327 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1328 which was used by userspace tools like iucode_tool and microcode.ctl.
1329 It is inadequate because it runs too late to be able to properly
1330 load microcode on a machine and it needs special tools. Instead, you
1331 should've switched to the early loading method with the initrd or
1332 builtin microcode by now: Documentation/x86/microcode.txt
1333
1334 config X86_MSR
1335 tristate "/dev/cpu/*/msr - Model-specific register support"
1336 ---help---
1337 This device gives privileged processes access to the x86
1338 Model-Specific Registers (MSRs). It is a character device with
1339 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1340 MSR accesses are directed to a specific CPU on multi-processor
1341 systems.
1342
1343 config X86_CPUID
1344 tristate "/dev/cpu/*/cpuid - CPU information support"
1345 ---help---
1346 This device gives processes access to the x86 CPUID instruction to
1347 be executed on a specific processor. It is a character device
1348 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1349 /dev/cpu/31/cpuid.
1350
1351 choice
1352 prompt "High Memory Support"
1353 default HIGHMEM4G
1354 depends on X86_32
1355
1356 config NOHIGHMEM
1357 bool "off"
1358 ---help---
1359 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1360 However, the address space of 32-bit x86 processors is only 4
1361 Gigabytes large. That means that, if you have a large amount of
1362 physical memory, not all of it can be "permanently mapped" by the
1363 kernel. The physical memory that's not permanently mapped is called
1364 "high memory".
1365
1366 If you are compiling a kernel which will never run on a machine with
1367 more than 1 Gigabyte total physical RAM, answer "off" here (default
1368 choice and suitable for most users). This will result in a "3GB/1GB"
1369 split: 3GB are mapped so that each process sees a 3GB virtual memory
1370 space and the remaining part of the 4GB virtual memory space is used
1371 by the kernel to permanently map as much physical memory as
1372 possible.
1373
1374 If the machine has between 1 and 4 Gigabytes physical RAM, then
1375 answer "4GB" here.
1376
1377 If more than 4 Gigabytes is used then answer "64GB" here. This
1378 selection turns Intel PAE (Physical Address Extension) mode on.
1379 PAE implements 3-level paging on IA32 processors. PAE is fully
1380 supported by Linux, PAE mode is implemented on all recent Intel
1381 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1382 then the kernel will not boot on CPUs that don't support PAE!
1383
1384 The actual amount of total physical memory will either be
1385 auto detected or can be forced by using a kernel command line option
1386 such as "mem=256M". (Try "man bootparam" or see the documentation of
1387 your boot loader (lilo or loadlin) about how to pass options to the
1388 kernel at boot time.)
1389
1390 If unsure, say "off".
1391
1392 config HIGHMEM4G
1393 bool "4GB"
1394 ---help---
1395 Select this if you have a 32-bit processor and between 1 and 4
1396 gigabytes of physical RAM.
1397
1398 config HIGHMEM64G
1399 bool "64GB"
1400 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1401 select X86_PAE
1402 ---help---
1403 Select this if you have a 32-bit processor and more than 4
1404 gigabytes of physical RAM.
1405
1406 endchoice
1407
1408 choice
1409 prompt "Memory split" if EXPERT
1410 default VMSPLIT_3G
1411 depends on X86_32
1412 ---help---
1413 Select the desired split between kernel and user memory.
1414
1415 If the address range available to the kernel is less than the
1416 physical memory installed, the remaining memory will be available
1417 as "high memory". Accessing high memory is a little more costly
1418 than low memory, as it needs to be mapped into the kernel first.
1419 Note that increasing the kernel address space limits the range
1420 available to user programs, making the address space there
1421 tighter. Selecting anything other than the default 3G/1G split
1422 will also likely make your kernel incompatible with binary-only
1423 kernel modules.
1424
1425 If you are not absolutely sure what you are doing, leave this
1426 option alone!
1427
1428 config VMSPLIT_3G
1429 bool "3G/1G user/kernel split"
1430 config VMSPLIT_3G_OPT
1431 depends on !X86_PAE
1432 bool "3G/1G user/kernel split (for full 1G low memory)"
1433 config VMSPLIT_2G
1434 bool "2G/2G user/kernel split"
1435 config VMSPLIT_2G_OPT
1436 depends on !X86_PAE
1437 bool "2G/2G user/kernel split (for full 2G low memory)"
1438 config VMSPLIT_1G
1439 bool "1G/3G user/kernel split"
1440 endchoice
1441
1442 config PAGE_OFFSET
1443 hex
1444 default 0xB0000000 if VMSPLIT_3G_OPT
1445 default 0x80000000 if VMSPLIT_2G
1446 default 0x78000000 if VMSPLIT_2G_OPT
1447 default 0x40000000 if VMSPLIT_1G
1448 default 0xC0000000
1449 depends on X86_32
1450
1451 config HIGHMEM
1452 def_bool y
1453 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1454
1455 config X86_PAE
1456 bool "PAE (Physical Address Extension) Support"
1457 depends on X86_32 && !HIGHMEM4G
1458 select PHYS_ADDR_T_64BIT
1459 select SWIOTLB
1460 ---help---
1461 PAE is required for NX support, and furthermore enables
1462 larger swapspace support for non-overcommit purposes. It
1463 has the cost of more pagetable lookup overhead, and also
1464 consumes more pagetable space per process.
1465
1466 config X86_5LEVEL
1467 bool "Enable 5-level page tables support"
1468 select DYNAMIC_MEMORY_LAYOUT
1469 select SPARSEMEM_VMEMMAP
1470 depends on X86_64
1471 ---help---
1472 5-level paging enables access to larger address space:
1473 upto 128 PiB of virtual address space and 4 PiB of
1474 physical address space.
1475
1476 It will be supported by future Intel CPUs.
1477
1478 A kernel with the option enabled can be booted on machines that
1479 support 4- or 5-level paging.
1480
1481 See Documentation/x86/x86_64/5level-paging.txt for more
1482 information.
1483
1484 Say N if unsure.
1485
1486 config X86_DIRECT_GBPAGES
1487 def_bool y
1488 depends on X86_64 && !DEBUG_PAGEALLOC
1489 ---help---
1490 Certain kernel features effectively disable kernel
1491 linear 1 GB mappings (even if the CPU otherwise
1492 supports them), so don't confuse the user by printing
1493 that we have them enabled.
1494
1495 config X86_CPA_STATISTICS
1496 bool "Enable statistic for Change Page Attribute"
1497 depends on DEBUG_FS
1498 ---help---
1499 Expose statistics about the Change Page Attribute mechanims, which
1500 helps to determine the effectiveness of preserving large and huge
1501 page mappings when mapping protections are changed.
1502
1503 config ARCH_HAS_MEM_ENCRYPT
1504 def_bool y
1505
1506 config AMD_MEM_ENCRYPT
1507 bool "AMD Secure Memory Encryption (SME) support"
1508 depends on X86_64 && CPU_SUP_AMD
1509 select DYNAMIC_PHYSICAL_MASK
1510 select ARCH_USE_MEMREMAP_PROT
1511 ---help---
1512 Say yes to enable support for the encryption of system memory.
1513 This requires an AMD processor that supports Secure Memory
1514 Encryption (SME).
1515
1516 config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1517 bool "Activate AMD Secure Memory Encryption (SME) by default"
1518 default y
1519 depends on AMD_MEM_ENCRYPT
1520 ---help---
1521 Say yes to have system memory encrypted by default if running on
1522 an AMD processor that supports Secure Memory Encryption (SME).
1523
1524 If set to Y, then the encryption of system memory can be
1525 deactivated with the mem_encrypt=off command line option.
1526
1527 If set to N, then the encryption of system memory can be
1528 activated with the mem_encrypt=on command line option.
1529
1530 # Common NUMA Features
1531 config NUMA
1532 bool "Numa Memory Allocation and Scheduler Support"
1533 depends on SMP
1534 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1535 default y if X86_BIGSMP
1536 ---help---
1537 Enable NUMA (Non Uniform Memory Access) support.
1538
1539 The kernel will try to allocate memory used by a CPU on the
1540 local memory controller of the CPU and add some more
1541 NUMA awareness to the kernel.
1542
1543 For 64-bit this is recommended if the system is Intel Core i7
1544 (or later), AMD Opteron, or EM64T NUMA.
1545
1546 For 32-bit this is only needed if you boot a 32-bit
1547 kernel on a 64-bit NUMA platform.
1548
1549 Otherwise, you should say N.
1550
1551 config AMD_NUMA
1552 def_bool y
1553 prompt "Old style AMD Opteron NUMA detection"
1554 depends on X86_64 && NUMA && PCI
1555 ---help---
1556 Enable AMD NUMA node topology detection. You should say Y here if
1557 you have a multi processor AMD system. This uses an old method to
1558 read the NUMA configuration directly from the builtin Northbridge
1559 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1560 which also takes priority if both are compiled in.
1561
1562 config X86_64_ACPI_NUMA
1563 def_bool y
1564 prompt "ACPI NUMA detection"
1565 depends on X86_64 && NUMA && ACPI && PCI
1566 select ACPI_NUMA
1567 ---help---
1568 Enable ACPI SRAT based node topology detection.
1569
1570 # Some NUMA nodes have memory ranges that span
1571 # other nodes. Even though a pfn is valid and
1572 # between a node's start and end pfns, it may not
1573 # reside on that node. See memmap_init_zone()
1574 # for details.
1575 config NODES_SPAN_OTHER_NODES
1576 def_bool y
1577 depends on X86_64_ACPI_NUMA
1578
1579 config NUMA_EMU
1580 bool "NUMA emulation"
1581 depends on NUMA
1582 ---help---
1583 Enable NUMA emulation. A flat machine will be split
1584 into virtual nodes when booted with "numa=fake=N", where N is the
1585 number of nodes. This is only useful for debugging.
1586
1587 config NODES_SHIFT
1588 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1589 range 1 10
1590 default "10" if MAXSMP
1591 default "6" if X86_64
1592 default "3"
1593 depends on NEED_MULTIPLE_NODES
1594 ---help---
1595 Specify the maximum number of NUMA Nodes available on the target
1596 system. Increases memory reserved to accommodate various tables.
1597
1598 config ARCH_HAVE_MEMORY_PRESENT
1599 def_bool y
1600 depends on X86_32 && DISCONTIGMEM
1601
1602 config ARCH_FLATMEM_ENABLE
1603 def_bool y
1604 depends on X86_32 && !NUMA
1605
1606 config ARCH_DISCONTIGMEM_ENABLE
1607 def_bool n
1608 depends on NUMA && X86_32
1609 depends on BROKEN
1610
1611 config ARCH_SPARSEMEM_ENABLE
1612 def_bool y
1613 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1614 select SPARSEMEM_STATIC if X86_32
1615 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1616
1617 config ARCH_SPARSEMEM_DEFAULT
1618 def_bool X86_64 || (NUMA && X86_32)
1619
1620 config ARCH_SELECT_MEMORY_MODEL
1621 def_bool y
1622 depends on ARCH_SPARSEMEM_ENABLE
1623
1624 config ARCH_MEMORY_PROBE
1625 bool "Enable sysfs memory/probe interface"
1626 depends on X86_64 && MEMORY_HOTPLUG
1627 help
1628 This option enables a sysfs memory/probe interface for testing.
1629 See Documentation/memory-hotplug.txt for more information.
1630 If you are unsure how to answer this question, answer N.
1631
1632 config ARCH_PROC_KCORE_TEXT
1633 def_bool y
1634 depends on X86_64 && PROC_KCORE
1635
1636 config ILLEGAL_POINTER_VALUE
1637 hex
1638 default 0 if X86_32
1639 default 0xdead000000000000 if X86_64
1640
1641 config X86_PMEM_LEGACY_DEVICE
1642 bool
1643
1644 config X86_PMEM_LEGACY
1645 tristate "Support non-standard NVDIMMs and ADR protected memory"
1646 depends on PHYS_ADDR_T_64BIT
1647 depends on BLK_DEV
1648 select X86_PMEM_LEGACY_DEVICE
1649 select LIBNVDIMM
1650 help
1651 Treat memory marked using the non-standard e820 type of 12 as used
1652 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1653 The kernel will offer these regions to the 'pmem' driver so
1654 they can be used for persistent storage.
1655
1656 Say Y if unsure.
1657
1658 config HIGHPTE
1659 bool "Allocate 3rd-level pagetables from highmem"
1660 depends on HIGHMEM
1661 ---help---
1662 The VM uses one page table entry for each page of physical memory.
1663 For systems with a lot of RAM, this can be wasteful of precious
1664 low memory. Setting this option will put user-space page table
1665 entries in high memory.
1666
1667 config X86_CHECK_BIOS_CORRUPTION
1668 bool "Check for low memory corruption"
1669 ---help---
1670 Periodically check for memory corruption in low memory, which
1671 is suspected to be caused by BIOS. Even when enabled in the
1672 configuration, it is disabled at runtime. Enable it by
1673 setting "memory_corruption_check=1" on the kernel command
1674 line. By default it scans the low 64k of memory every 60
1675 seconds; see the memory_corruption_check_size and
1676 memory_corruption_check_period parameters in
1677 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1678
1679 When enabled with the default parameters, this option has
1680 almost no overhead, as it reserves a relatively small amount
1681 of memory and scans it infrequently. It both detects corruption
1682 and prevents it from affecting the running system.
1683
1684 It is, however, intended as a diagnostic tool; if repeatable
1685 BIOS-originated corruption always affects the same memory,
1686 you can use memmap= to prevent the kernel from using that
1687 memory.
1688
1689 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1690 bool "Set the default setting of memory_corruption_check"
1691 depends on X86_CHECK_BIOS_CORRUPTION
1692 default y
1693 ---help---
1694 Set whether the default state of memory_corruption_check is
1695 on or off.
1696
1697 config X86_RESERVE_LOW
1698 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1699 default 64
1700 range 4 640
1701 ---help---
1702 Specify the amount of low memory to reserve for the BIOS.
1703
1704 The first page contains BIOS data structures that the kernel
1705 must not use, so that page must always be reserved.
1706
1707 By default we reserve the first 64K of physical RAM, as a
1708 number of BIOSes are known to corrupt that memory range
1709 during events such as suspend/resume or monitor cable
1710 insertion, so it must not be used by the kernel.
1711
1712 You can set this to 4 if you are absolutely sure that you
1713 trust the BIOS to get all its memory reservations and usages
1714 right. If you know your BIOS have problems beyond the
1715 default 64K area, you can set this to 640 to avoid using the
1716 entire low memory range.
1717
1718 If you have doubts about the BIOS (e.g. suspend/resume does
1719 not work or there's kernel crashes after certain hardware
1720 hotplug events) then you might want to enable
1721 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1722 typical corruption patterns.
1723
1724 Leave this to the default value of 64 if you are unsure.
1725
1726 config MATH_EMULATION
1727 bool
1728 depends on MODIFY_LDT_SYSCALL
1729 prompt "Math emulation" if X86_32
1730 ---help---
1731 Linux can emulate a math coprocessor (used for floating point
1732 operations) if you don't have one. 486DX and Pentium processors have
1733 a math coprocessor built in, 486SX and 386 do not, unless you added
1734 a 487DX or 387, respectively. (The messages during boot time can
1735 give you some hints here ["man dmesg"].) Everyone needs either a
1736 coprocessor or this emulation.
1737
1738 If you don't have a math coprocessor, you need to say Y here; if you
1739 say Y here even though you have a coprocessor, the coprocessor will
1740 be used nevertheless. (This behavior can be changed with the kernel
1741 command line option "no387", which comes handy if your coprocessor
1742 is broken. Try "man bootparam" or see the documentation of your boot
1743 loader (lilo or loadlin) about how to pass options to the kernel at
1744 boot time.) This means that it is a good idea to say Y here if you
1745 intend to use this kernel on different machines.
1746
1747 More information about the internals of the Linux math coprocessor
1748 emulation can be found in <file:arch/x86/math-emu/README>.
1749
1750 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1751 kernel, it won't hurt.
1752
1753 config MTRR
1754 def_bool y
1755 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1756 ---help---
1757 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1758 the Memory Type Range Registers (MTRRs) may be used to control
1759 processor access to memory ranges. This is most useful if you have
1760 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1761 allows bus write transfers to be combined into a larger transfer
1762 before bursting over the PCI/AGP bus. This can increase performance
1763 of image write operations 2.5 times or more. Saying Y here creates a
1764 /proc/mtrr file which may be used to manipulate your processor's
1765 MTRRs. Typically the X server should use this.
1766
1767 This code has a reasonably generic interface so that similar
1768 control registers on other processors can be easily supported
1769 as well:
1770
1771 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1772 Registers (ARRs) which provide a similar functionality to MTRRs. For
1773 these, the ARRs are used to emulate the MTRRs.
1774 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1775 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1776 write-combining. All of these processors are supported by this code
1777 and it makes sense to say Y here if you have one of them.
1778
1779 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1780 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1781 can lead to all sorts of problems, so it's good to say Y here.
1782
1783 You can safely say Y even if your machine doesn't have MTRRs, you'll
1784 just add about 9 KB to your kernel.
1785
1786 See <file:Documentation/x86/mtrr.txt> for more information.
1787
1788 config MTRR_SANITIZER
1789 def_bool y
1790 prompt "MTRR cleanup support"
1791 depends on MTRR
1792 ---help---
1793 Convert MTRR layout from continuous to discrete, so X drivers can
1794 add writeback entries.
1795
1796 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1797 The largest mtrr entry size for a continuous block can be set with
1798 mtrr_chunk_size.
1799
1800 If unsure, say Y.
1801
1802 config MTRR_SANITIZER_ENABLE_DEFAULT
1803 int "MTRR cleanup enable value (0-1)"
1804 range 0 1
1805 default "0"
1806 depends on MTRR_SANITIZER
1807 ---help---
1808 Enable mtrr cleanup default value
1809
1810 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1811 int "MTRR cleanup spare reg num (0-7)"
1812 range 0 7
1813 default "1"
1814 depends on MTRR_SANITIZER
1815 ---help---
1816 mtrr cleanup spare entries default, it can be changed via
1817 mtrr_spare_reg_nr=N on the kernel command line.
1818
1819 config X86_PAT
1820 def_bool y
1821 prompt "x86 PAT support" if EXPERT
1822 depends on MTRR
1823 ---help---
1824 Use PAT attributes to setup page level cache control.
1825
1826 PATs are the modern equivalents of MTRRs and are much more
1827 flexible than MTRRs.
1828
1829 Say N here if you see bootup problems (boot crash, boot hang,
1830 spontaneous reboots) or a non-working video driver.
1831
1832 If unsure, say Y.
1833
1834 config ARCH_USES_PG_UNCACHED
1835 def_bool y
1836 depends on X86_PAT
1837
1838 config ARCH_RANDOM
1839 def_bool y
1840 prompt "x86 architectural random number generator" if EXPERT
1841 ---help---
1842 Enable the x86 architectural RDRAND instruction
1843 (Intel Bull Mountain technology) to generate random numbers.
1844 If supported, this is a high bandwidth, cryptographically
1845 secure hardware random number generator.
1846
1847 config X86_SMAP
1848 def_bool y
1849 prompt "Supervisor Mode Access Prevention" if EXPERT
1850 ---help---
1851 Supervisor Mode Access Prevention (SMAP) is a security
1852 feature in newer Intel processors. There is a small
1853 performance cost if this enabled and turned on; there is
1854 also a small increase in the kernel size if this is enabled.
1855
1856 If unsure, say Y.
1857
1858 config X86_INTEL_UMIP
1859 def_bool y
1860 depends on CPU_SUP_INTEL
1861 prompt "Intel User Mode Instruction Prevention" if EXPERT
1862 ---help---
1863 The User Mode Instruction Prevention (UMIP) is a security
1864 feature in newer Intel processors. If enabled, a general
1865 protection fault is issued if the SGDT, SLDT, SIDT, SMSW
1866 or STR instructions are executed in user mode. These instructions
1867 unnecessarily expose information about the hardware state.
1868
1869 The vast majority of applications do not use these instructions.
1870 For the very few that do, software emulation is provided in
1871 specific cases in protected and virtual-8086 modes. Emulated
1872 results are dummy.
1873
1874 config X86_INTEL_MPX
1875 prompt "Intel MPX (Memory Protection Extensions)"
1876 def_bool n
1877 # Note: only available in 64-bit mode due to VMA flags shortage
1878 depends on CPU_SUP_INTEL && X86_64
1879 select ARCH_USES_HIGH_VMA_FLAGS
1880 ---help---
1881 MPX provides hardware features that can be used in
1882 conjunction with compiler-instrumented code to check
1883 memory references. It is designed to detect buffer
1884 overflow or underflow bugs.
1885
1886 This option enables running applications which are
1887 instrumented or otherwise use MPX. It does not use MPX
1888 itself inside the kernel or to protect the kernel
1889 against bad memory references.
1890
1891 Enabling this option will make the kernel larger:
1892 ~8k of kernel text and 36 bytes of data on a 64-bit
1893 defconfig. It adds a long to the 'mm_struct' which
1894 will increase the kernel memory overhead of each
1895 process and adds some branches to paths used during
1896 exec() and munmap().
1897
1898 For details, see Documentation/x86/intel_mpx.txt
1899
1900 If unsure, say N.
1901
1902 config X86_INTEL_MEMORY_PROTECTION_KEYS
1903 prompt "Intel Memory Protection Keys"
1904 def_bool y
1905 # Note: only available in 64-bit mode
1906 depends on CPU_SUP_INTEL && X86_64
1907 select ARCH_USES_HIGH_VMA_FLAGS
1908 select ARCH_HAS_PKEYS
1909 ---help---
1910 Memory Protection Keys provides a mechanism for enforcing
1911 page-based protections, but without requiring modification of the
1912 page tables when an application changes protection domains.
1913
1914 For details, see Documentation/x86/protection-keys.txt
1915
1916 If unsure, say y.
1917
1918 config EFI
1919 bool "EFI runtime service support"
1920 depends on ACPI
1921 select UCS2_STRING
1922 select EFI_RUNTIME_WRAPPERS
1923 ---help---
1924 This enables the kernel to use EFI runtime services that are
1925 available (such as the EFI variable services).
1926
1927 This option is only useful on systems that have EFI firmware.
1928 In addition, you should use the latest ELILO loader available
1929 at <http://elilo.sourceforge.net> in order to take advantage
1930 of EFI runtime services. However, even with this option, the
1931 resultant kernel should continue to boot on existing non-EFI
1932 platforms.
1933
1934 config EFI_STUB
1935 bool "EFI stub support"
1936 depends on EFI && !X86_USE_3DNOW
1937 select RELOCATABLE
1938 ---help---
1939 This kernel feature allows a bzImage to be loaded directly
1940 by EFI firmware without the use of a bootloader.
1941
1942 See Documentation/efi-stub.txt for more information.
1943
1944 config EFI_MIXED
1945 bool "EFI mixed-mode support"
1946 depends on EFI_STUB && X86_64
1947 ---help---
1948 Enabling this feature allows a 64-bit kernel to be booted
1949 on a 32-bit firmware, provided that your CPU supports 64-bit
1950 mode.
1951
1952 Note that it is not possible to boot a mixed-mode enabled
1953 kernel via the EFI boot stub - a bootloader that supports
1954 the EFI handover protocol must be used.
1955
1956 If unsure, say N.
1957
1958 config SECCOMP
1959 def_bool y
1960 prompt "Enable seccomp to safely compute untrusted bytecode"
1961 ---help---
1962 This kernel feature is useful for number crunching applications
1963 that may need to compute untrusted bytecode during their
1964 execution. By using pipes or other transports made available to
1965 the process as file descriptors supporting the read/write
1966 syscalls, it's possible to isolate those applications in
1967 their own address space using seccomp. Once seccomp is
1968 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1969 and the task is only allowed to execute a few safe syscalls
1970 defined by each seccomp mode.
1971
1972 If unsure, say Y. Only embedded should say N here.
1973
1974 source "kernel/Kconfig.hz"
1975
1976 config KEXEC
1977 bool "kexec system call"
1978 select KEXEC_CORE
1979 ---help---
1980 kexec is a system call that implements the ability to shutdown your
1981 current kernel, and to start another kernel. It is like a reboot
1982 but it is independent of the system firmware. And like a reboot
1983 you can start any kernel with it, not just Linux.
1984
1985 The name comes from the similarity to the exec system call.
1986
1987 It is an ongoing process to be certain the hardware in a machine
1988 is properly shutdown, so do not be surprised if this code does not
1989 initially work for you. As of this writing the exact hardware
1990 interface is strongly in flux, so no good recommendation can be
1991 made.
1992
1993 config KEXEC_FILE
1994 bool "kexec file based system call"
1995 select KEXEC_CORE
1996 select BUILD_BIN2C
1997 depends on X86_64
1998 depends on CRYPTO=y
1999 depends on CRYPTO_SHA256=y
2000 ---help---
2001 This is new version of kexec system call. This system call is
2002 file based and takes file descriptors as system call argument
2003 for kernel and initramfs as opposed to list of segments as
2004 accepted by previous system call.
2005
2006 config ARCH_HAS_KEXEC_PURGATORY
2007 def_bool KEXEC_FILE
2008
2009 config KEXEC_VERIFY_SIG
2010 bool "Verify kernel signature during kexec_file_load() syscall"
2011 depends on KEXEC_FILE
2012 ---help---
2013 This option makes kernel signature verification mandatory for
2014 the kexec_file_load() syscall.
2015
2016 In addition to that option, you need to enable signature
2017 verification for the corresponding kernel image type being
2018 loaded in order for this to work.
2019
2020 config KEXEC_BZIMAGE_VERIFY_SIG
2021 bool "Enable bzImage signature verification support"
2022 depends on KEXEC_VERIFY_SIG
2023 depends on SIGNED_PE_FILE_VERIFICATION
2024 select SYSTEM_TRUSTED_KEYRING
2025 ---help---
2026 Enable bzImage signature verification support.
2027
2028 config CRASH_DUMP
2029 bool "kernel crash dumps"
2030 depends on X86_64 || (X86_32 && HIGHMEM)
2031 ---help---
2032 Generate crash dump after being started by kexec.
2033 This should be normally only set in special crash dump kernels
2034 which are loaded in the main kernel with kexec-tools into
2035 a specially reserved region and then later executed after
2036 a crash by kdump/kexec. The crash dump kernel must be compiled
2037 to a memory address not used by the main kernel or BIOS using
2038 PHYSICAL_START, or it must be built as a relocatable image
2039 (CONFIG_RELOCATABLE=y).
2040 For more details see Documentation/kdump/kdump.txt
2041
2042 config KEXEC_JUMP
2043 bool "kexec jump"
2044 depends on KEXEC && HIBERNATION
2045 ---help---
2046 Jump between original kernel and kexeced kernel and invoke
2047 code in physical address mode via KEXEC
2048
2049 config PHYSICAL_START
2050 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2051 default "0x1000000"
2052 ---help---
2053 This gives the physical address where the kernel is loaded.
2054
2055 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2056 bzImage will decompress itself to above physical address and
2057 run from there. Otherwise, bzImage will run from the address where
2058 it has been loaded by the boot loader and will ignore above physical
2059 address.
2060
2061 In normal kdump cases one does not have to set/change this option
2062 as now bzImage can be compiled as a completely relocatable image
2063 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2064 address. This option is mainly useful for the folks who don't want
2065 to use a bzImage for capturing the crash dump and want to use a
2066 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2067 to be specifically compiled to run from a specific memory area
2068 (normally a reserved region) and this option comes handy.
2069
2070 So if you are using bzImage for capturing the crash dump,
2071 leave the value here unchanged to 0x1000000 and set
2072 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2073 for capturing the crash dump change this value to start of
2074 the reserved region. In other words, it can be set based on
2075 the "X" value as specified in the "crashkernel=YM@XM"
2076 command line boot parameter passed to the panic-ed
2077 kernel. Please take a look at Documentation/kdump/kdump.txt
2078 for more details about crash dumps.
2079
2080 Usage of bzImage for capturing the crash dump is recommended as
2081 one does not have to build two kernels. Same kernel can be used
2082 as production kernel and capture kernel. Above option should have
2083 gone away after relocatable bzImage support is introduced. But it
2084 is present because there are users out there who continue to use
2085 vmlinux for dump capture. This option should go away down the
2086 line.
2087
2088 Don't change this unless you know what you are doing.
2089
2090 config RELOCATABLE
2091 bool "Build a relocatable kernel"
2092 default y
2093 ---help---
2094 This builds a kernel image that retains relocation information
2095 so it can be loaded someplace besides the default 1MB.
2096 The relocations tend to make the kernel binary about 10% larger,
2097 but are discarded at runtime.
2098
2099 One use is for the kexec on panic case where the recovery kernel
2100 must live at a different physical address than the primary
2101 kernel.
2102
2103 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2104 it has been loaded at and the compile time physical address
2105 (CONFIG_PHYSICAL_START) is used as the minimum location.
2106
2107 config RANDOMIZE_BASE
2108 bool "Randomize the address of the kernel image (KASLR)"
2109 depends on RELOCATABLE
2110 default y
2111 ---help---
2112 In support of Kernel Address Space Layout Randomization (KASLR),
2113 this randomizes the physical address at which the kernel image
2114 is decompressed and the virtual address where the kernel
2115 image is mapped, as a security feature that deters exploit
2116 attempts relying on knowledge of the location of kernel
2117 code internals.
2118
2119 On 64-bit, the kernel physical and virtual addresses are
2120 randomized separately. The physical address will be anywhere
2121 between 16MB and the top of physical memory (up to 64TB). The
2122 virtual address will be randomized from 16MB up to 1GB (9 bits
2123 of entropy). Note that this also reduces the memory space
2124 available to kernel modules from 1.5GB to 1GB.
2125
2126 On 32-bit, the kernel physical and virtual addresses are
2127 randomized together. They will be randomized from 16MB up to
2128 512MB (8 bits of entropy).
2129
2130 Entropy is generated using the RDRAND instruction if it is
2131 supported. If RDTSC is supported, its value is mixed into
2132 the entropy pool as well. If neither RDRAND nor RDTSC are
2133 supported, then entropy is read from the i8254 timer. The
2134 usable entropy is limited by the kernel being built using
2135 2GB addressing, and that PHYSICAL_ALIGN must be at a
2136 minimum of 2MB. As a result, only 10 bits of entropy are
2137 theoretically possible, but the implementations are further
2138 limited due to memory layouts.
2139
2140 If unsure, say Y.
2141
2142 # Relocation on x86 needs some additional build support
2143 config X86_NEED_RELOCS
2144 def_bool y
2145 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2146
2147 config PHYSICAL_ALIGN
2148 hex "Alignment value to which kernel should be aligned"
2149 default "0x200000"
2150 range 0x2000 0x1000000 if X86_32
2151 range 0x200000 0x1000000 if X86_64
2152 ---help---
2153 This value puts the alignment restrictions on physical address
2154 where kernel is loaded and run from. Kernel is compiled for an
2155 address which meets above alignment restriction.
2156
2157 If bootloader loads the kernel at a non-aligned address and
2158 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2159 address aligned to above value and run from there.
2160
2161 If bootloader loads the kernel at a non-aligned address and
2162 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2163 load address and decompress itself to the address it has been
2164 compiled for and run from there. The address for which kernel is
2165 compiled already meets above alignment restrictions. Hence the
2166 end result is that kernel runs from a physical address meeting
2167 above alignment restrictions.
2168
2169 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2170 this value must be a multiple of 0x200000.
2171
2172 Don't change this unless you know what you are doing.
2173
2174 config DYNAMIC_MEMORY_LAYOUT
2175 bool
2176 ---help---
2177 This option makes base addresses of vmalloc and vmemmap as well as
2178 __PAGE_OFFSET movable during boot.
2179
2180 config RANDOMIZE_MEMORY
2181 bool "Randomize the kernel memory sections"
2182 depends on X86_64
2183 depends on RANDOMIZE_BASE
2184 select DYNAMIC_MEMORY_LAYOUT
2185 default RANDOMIZE_BASE
2186 ---help---
2187 Randomizes the base virtual address of kernel memory sections
2188 (physical memory mapping, vmalloc & vmemmap). This security feature
2189 makes exploits relying on predictable memory locations less reliable.
2190
2191 The order of allocations remains unchanged. Entropy is generated in
2192 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2193 configuration have in average 30,000 different possible virtual
2194 addresses for each memory section.
2195
2196 If unsure, say Y.
2197
2198 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2199 hex "Physical memory mapping padding" if EXPERT
2200 depends on RANDOMIZE_MEMORY
2201 default "0xa" if MEMORY_HOTPLUG
2202 default "0x0"
2203 range 0x1 0x40 if MEMORY_HOTPLUG
2204 range 0x0 0x40
2205 ---help---
2206 Define the padding in terabytes added to the existing physical
2207 memory size during kernel memory randomization. It is useful
2208 for memory hotplug support but reduces the entropy available for
2209 address randomization.
2210
2211 If unsure, leave at the default value.
2212
2213 config HOTPLUG_CPU
2214 def_bool y
2215 depends on SMP
2216
2217 config BOOTPARAM_HOTPLUG_CPU0
2218 bool "Set default setting of cpu0_hotpluggable"
2219 depends on HOTPLUG_CPU
2220 ---help---
2221 Set whether default state of cpu0_hotpluggable is on or off.
2222
2223 Say Y here to enable CPU0 hotplug by default. If this switch
2224 is turned on, there is no need to give cpu0_hotplug kernel
2225 parameter and the CPU0 hotplug feature is enabled by default.
2226
2227 Please note: there are two known CPU0 dependencies if you want
2228 to enable the CPU0 hotplug feature either by this switch or by
2229 cpu0_hotplug kernel parameter.
2230
2231 First, resume from hibernate or suspend always starts from CPU0.
2232 So hibernate and suspend are prevented if CPU0 is offline.
2233
2234 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2235 offline if any interrupt can not migrate out of CPU0. There may
2236 be other CPU0 dependencies.
2237
2238 Please make sure the dependencies are under your control before
2239 you enable this feature.
2240
2241 Say N if you don't want to enable CPU0 hotplug feature by default.
2242 You still can enable the CPU0 hotplug feature at boot by kernel
2243 parameter cpu0_hotplug.
2244
2245 config DEBUG_HOTPLUG_CPU0
2246 def_bool n
2247 prompt "Debug CPU0 hotplug"
2248 depends on HOTPLUG_CPU
2249 ---help---
2250 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2251 soon as possible and boots up userspace with CPU0 offlined. User
2252 can online CPU0 back after boot time.
2253
2254 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2255 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2256 compilation or giving cpu0_hotplug kernel parameter at boot.
2257
2258 If unsure, say N.
2259
2260 config COMPAT_VDSO
2261 def_bool n
2262 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2263 depends on COMPAT_32
2264 ---help---
2265 Certain buggy versions of glibc will crash if they are
2266 presented with a 32-bit vDSO that is not mapped at the address
2267 indicated in its segment table.
2268
2269 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2270 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2271 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2272 the only released version with the bug, but OpenSUSE 9
2273 contains a buggy "glibc 2.3.2".
2274
2275 The symptom of the bug is that everything crashes on startup, saying:
2276 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2277
2278 Saying Y here changes the default value of the vdso32 boot
2279 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2280 This works around the glibc bug but hurts performance.
2281
2282 If unsure, say N: if you are compiling your own kernel, you
2283 are unlikely to be using a buggy version of glibc.
2284
2285 choice
2286 prompt "vsyscall table for legacy applications"
2287 depends on X86_64
2288 default LEGACY_VSYSCALL_EMULATE
2289 help
2290 Legacy user code that does not know how to find the vDSO expects
2291 to be able to issue three syscalls by calling fixed addresses in
2292 kernel space. Since this location is not randomized with ASLR,
2293 it can be used to assist security vulnerability exploitation.
2294
2295 This setting can be changed at boot time via the kernel command
2296 line parameter vsyscall=[emulate|none].
2297
2298 On a system with recent enough glibc (2.14 or newer) and no
2299 static binaries, you can say None without a performance penalty
2300 to improve security.
2301
2302 If unsure, select "Emulate".
2303
2304 config LEGACY_VSYSCALL_EMULATE
2305 bool "Emulate"
2306 help
2307 The kernel traps and emulates calls into the fixed
2308 vsyscall address mapping. This makes the mapping
2309 non-executable, but it still contains known contents,
2310 which could be used in certain rare security vulnerability
2311 exploits. This configuration is recommended when userspace
2312 still uses the vsyscall area.
2313
2314 config LEGACY_VSYSCALL_NONE
2315 bool "None"
2316 help
2317 There will be no vsyscall mapping at all. This will
2318 eliminate any risk of ASLR bypass due to the vsyscall
2319 fixed address mapping. Attempts to use the vsyscalls
2320 will be reported to dmesg, so that either old or
2321 malicious userspace programs can be identified.
2322
2323 endchoice
2324
2325 config CMDLINE_BOOL
2326 bool "Built-in kernel command line"
2327 ---help---
2328 Allow for specifying boot arguments to the kernel at
2329 build time. On some systems (e.g. embedded ones), it is
2330 necessary or convenient to provide some or all of the
2331 kernel boot arguments with the kernel itself (that is,
2332 to not rely on the boot loader to provide them.)
2333
2334 To compile command line arguments into the kernel,
2335 set this option to 'Y', then fill in the
2336 boot arguments in CONFIG_CMDLINE.
2337
2338 Systems with fully functional boot loaders (i.e. non-embedded)
2339 should leave this option set to 'N'.
2340
2341 config CMDLINE
2342 string "Built-in kernel command string"
2343 depends on CMDLINE_BOOL
2344 default ""
2345 ---help---
2346 Enter arguments here that should be compiled into the kernel
2347 image and used at boot time. If the boot loader provides a
2348 command line at boot time, it is appended to this string to
2349 form the full kernel command line, when the system boots.
2350
2351 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2352 change this behavior.
2353
2354 In most cases, the command line (whether built-in or provided
2355 by the boot loader) should specify the device for the root
2356 file system.
2357
2358 config CMDLINE_OVERRIDE
2359 bool "Built-in command line overrides boot loader arguments"
2360 depends on CMDLINE_BOOL
2361 ---help---
2362 Set this option to 'Y' to have the kernel ignore the boot loader
2363 command line, and use ONLY the built-in command line.
2364
2365 This is used to work around broken boot loaders. This should
2366 be set to 'N' under normal conditions.
2367
2368 config MODIFY_LDT_SYSCALL
2369 bool "Enable the LDT (local descriptor table)" if EXPERT
2370 default y
2371 ---help---
2372 Linux can allow user programs to install a per-process x86
2373 Local Descriptor Table (LDT) using the modify_ldt(2) system
2374 call. This is required to run 16-bit or segmented code such as
2375 DOSEMU or some Wine programs. It is also used by some very old
2376 threading libraries.
2377
2378 Enabling this feature adds a small amount of overhead to
2379 context switches and increases the low-level kernel attack
2380 surface. Disabling it removes the modify_ldt(2) system call.
2381
2382 Saying 'N' here may make sense for embedded or server kernels.
2383
2384 source "kernel/livepatch/Kconfig"
2385
2386 endmenu
2387
2388 config ARCH_HAS_ADD_PAGES
2389 def_bool y
2390 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2391
2392 config ARCH_ENABLE_MEMORY_HOTPLUG
2393 def_bool y
2394 depends on X86_64 || (X86_32 && HIGHMEM)
2395
2396 config ARCH_ENABLE_MEMORY_HOTREMOVE
2397 def_bool y
2398 depends on MEMORY_HOTPLUG
2399
2400 config USE_PERCPU_NUMA_NODE_ID
2401 def_bool y
2402 depends on NUMA
2403
2404 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2405 def_bool y
2406 depends on X86_64 || X86_PAE
2407
2408 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2409 def_bool y
2410 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2411
2412 config ARCH_ENABLE_THP_MIGRATION
2413 def_bool y
2414 depends on X86_64 && TRANSPARENT_HUGEPAGE
2415
2416 menu "Power management and ACPI options"
2417
2418 config ARCH_HIBERNATION_HEADER
2419 def_bool y
2420 depends on HIBERNATION
2421
2422 source "kernel/power/Kconfig"
2423
2424 source "drivers/acpi/Kconfig"
2425
2426 source "drivers/sfi/Kconfig"
2427
2428 config X86_APM_BOOT
2429 def_bool y
2430 depends on APM
2431
2432 menuconfig APM
2433 tristate "APM (Advanced Power Management) BIOS support"
2434 depends on X86_32 && PM_SLEEP
2435 ---help---
2436 APM is a BIOS specification for saving power using several different
2437 techniques. This is mostly useful for battery powered laptops with
2438 APM compliant BIOSes. If you say Y here, the system time will be
2439 reset after a RESUME operation, the /proc/apm device will provide
2440 battery status information, and user-space programs will receive
2441 notification of APM "events" (e.g. battery status change).
2442
2443 If you select "Y" here, you can disable actual use of the APM
2444 BIOS by passing the "apm=off" option to the kernel at boot time.
2445
2446 Note that the APM support is almost completely disabled for
2447 machines with more than one CPU.
2448
2449 In order to use APM, you will need supporting software. For location
2450 and more information, read <file:Documentation/power/apm-acpi.rst>
2451 and the Battery Powered Linux mini-HOWTO, available from
2452 <http://www.tldp.org/docs.html#howto>.
2453
2454 This driver does not spin down disk drives (see the hdparm(8)
2455 manpage ("man 8 hdparm") for that), and it doesn't turn off
2456 VESA-compliant "green" monitors.
2457
2458 This driver does not support the TI 4000M TravelMate and the ACER
2459 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2460 desktop machines also don't have compliant BIOSes, and this driver
2461 may cause those machines to panic during the boot phase.
2462
2463 Generally, if you don't have a battery in your machine, there isn't
2464 much point in using this driver and you should say N. If you get
2465 random kernel OOPSes or reboots that don't seem to be related to
2466 anything, try disabling/enabling this option (or disabling/enabling
2467 APM in your BIOS).
2468
2469 Some other things you should try when experiencing seemingly random,
2470 "weird" problems:
2471
2472 1) make sure that you have enough swap space and that it is
2473 enabled.
2474 2) pass the "no-hlt" option to the kernel
2475 3) switch on floating point emulation in the kernel and pass
2476 the "no387" option to the kernel
2477 4) pass the "floppy=nodma" option to the kernel
2478 5) pass the "mem=4M" option to the kernel (thereby disabling
2479 all but the first 4 MB of RAM)
2480 6) make sure that the CPU is not over clocked.
2481 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2482 8) disable the cache from your BIOS settings
2483 9) install a fan for the video card or exchange video RAM
2484 10) install a better fan for the CPU
2485 11) exchange RAM chips
2486 12) exchange the motherboard.
2487
2488 To compile this driver as a module, choose M here: the
2489 module will be called apm.
2490
2491 if APM
2492
2493 config APM_IGNORE_USER_SUSPEND
2494 bool "Ignore USER SUSPEND"
2495 ---help---
2496 This option will ignore USER SUSPEND requests. On machines with a
2497 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2498 series notebooks, it is necessary to say Y because of a BIOS bug.
2499
2500 config APM_DO_ENABLE
2501 bool "Enable PM at boot time"
2502 ---help---
2503 Enable APM features at boot time. From page 36 of the APM BIOS
2504 specification: "When disabled, the APM BIOS does not automatically
2505 power manage devices, enter the Standby State, enter the Suspend
2506 State, or take power saving steps in response to CPU Idle calls."
2507 This driver will make CPU Idle calls when Linux is idle (unless this
2508 feature is turned off -- see "Do CPU IDLE calls", below). This
2509 should always save battery power, but more complicated APM features
2510 will be dependent on your BIOS implementation. You may need to turn
2511 this option off if your computer hangs at boot time when using APM
2512 support, or if it beeps continuously instead of suspending. Turn
2513 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2514 T400CDT. This is off by default since most machines do fine without
2515 this feature.
2516
2517 config APM_CPU_IDLE
2518 depends on CPU_IDLE
2519 bool "Make CPU Idle calls when idle"
2520 ---help---
2521 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2522 On some machines, this can activate improved power savings, such as
2523 a slowed CPU clock rate, when the machine is idle. These idle calls
2524 are made after the idle loop has run for some length of time (e.g.,
2525 333 mS). On some machines, this will cause a hang at boot time or
2526 whenever the CPU becomes idle. (On machines with more than one CPU,
2527 this option does nothing.)
2528
2529 config APM_DISPLAY_BLANK
2530 bool "Enable console blanking using APM"
2531 ---help---
2532 Enable console blanking using the APM. Some laptops can use this to
2533 turn off the LCD backlight when the screen blanker of the Linux
2534 virtual console blanks the screen. Note that this is only used by
2535 the virtual console screen blanker, and won't turn off the backlight
2536 when using the X Window system. This also doesn't have anything to
2537 do with your VESA-compliant power-saving monitor. Further, this
2538 option doesn't work for all laptops -- it might not turn off your
2539 backlight at all, or it might print a lot of errors to the console,
2540 especially if you are using gpm.
2541
2542 config APM_ALLOW_INTS
2543 bool "Allow interrupts during APM BIOS calls"
2544 ---help---
2545 Normally we disable external interrupts while we are making calls to
2546 the APM BIOS as a measure to lessen the effects of a badly behaving
2547 BIOS implementation. The BIOS should reenable interrupts if it
2548 needs to. Unfortunately, some BIOSes do not -- especially those in
2549 many of the newer IBM Thinkpads. If you experience hangs when you
2550 suspend, try setting this to Y. Otherwise, say N.
2551
2552 endif # APM
2553
2554 source "drivers/cpufreq/Kconfig"
2555
2556 source "drivers/cpuidle/Kconfig"
2557
2558 source "drivers/idle/Kconfig"
2559
2560 endmenu
2561
2562
2563 menu "Bus options (PCI etc.)"
2564
2565 choice
2566 prompt "PCI access mode"
2567 depends on X86_32 && PCI
2568 default PCI_GOANY
2569 ---help---
2570 On PCI systems, the BIOS can be used to detect the PCI devices and
2571 determine their configuration. However, some old PCI motherboards
2572 have BIOS bugs and may crash if this is done. Also, some embedded
2573 PCI-based systems don't have any BIOS at all. Linux can also try to
2574 detect the PCI hardware directly without using the BIOS.
2575
2576 With this option, you can specify how Linux should detect the
2577 PCI devices. If you choose "BIOS", the BIOS will be used,
2578 if you choose "Direct", the BIOS won't be used, and if you
2579 choose "MMConfig", then PCI Express MMCONFIG will be used.
2580 If you choose "Any", the kernel will try MMCONFIG, then the
2581 direct access method and falls back to the BIOS if that doesn't
2582 work. If unsure, go with the default, which is "Any".
2583
2584 config PCI_GOBIOS
2585 bool "BIOS"
2586
2587 config PCI_GOMMCONFIG
2588 bool "MMConfig"
2589
2590 config PCI_GODIRECT
2591 bool "Direct"
2592
2593 config PCI_GOOLPC
2594 bool "OLPC XO-1"
2595 depends on OLPC
2596
2597 config PCI_GOANY
2598 bool "Any"
2599
2600 endchoice
2601
2602 config PCI_BIOS
2603 def_bool y
2604 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2605
2606 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2607 config PCI_DIRECT
2608 def_bool y
2609 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2610
2611 config PCI_MMCONFIG
2612 bool "Support mmconfig PCI config space access" if X86_64
2613 default y
2614 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2615 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2616
2617 config PCI_OLPC
2618 def_bool y
2619 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2620
2621 config PCI_XEN
2622 def_bool y
2623 depends on PCI && XEN
2624 select SWIOTLB_XEN
2625
2626 config MMCONF_FAM10H
2627 def_bool y
2628 depends on X86_64 && PCI_MMCONFIG && ACPI
2629
2630 config PCI_CNB20LE_QUIRK
2631 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2632 depends on PCI
2633 help
2634 Read the PCI windows out of the CNB20LE host bridge. This allows
2635 PCI hotplug to work on systems with the CNB20LE chipset which do
2636 not have ACPI.
2637
2638 There's no public spec for this chipset, and this functionality
2639 is known to be incomplete.
2640
2641 You should say N unless you know you need this.
2642
2643 config ISA_BUS
2644 bool "ISA bus support on modern systems" if EXPERT
2645 help
2646 Expose ISA bus device drivers and options available for selection and
2647 configuration. Enable this option if your target machine has an ISA
2648 bus. ISA is an older system, displaced by PCI and newer bus
2649 architectures -- if your target machine is modern, it probably does
2650 not have an ISA bus.
2651
2652 If unsure, say N.
2653
2654 # x86_64 have no ISA slots, but can have ISA-style DMA.
2655 config ISA_DMA_API
2656 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2657 default y
2658 help
2659 Enables ISA-style DMA support for devices requiring such controllers.
2660 If unsure, say Y.
2661
2662 if X86_32
2663
2664 config ISA
2665 bool "ISA support"
2666 ---help---
2667 Find out whether you have ISA slots on your motherboard. ISA is the
2668 name of a bus system, i.e. the way the CPU talks to the other stuff
2669 inside your box. Other bus systems are PCI, EISA, MicroChannel
2670 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2671 newer boards don't support it. If you have ISA, say Y, otherwise N.
2672
2673 config SCx200
2674 tristate "NatSemi SCx200 support"
2675 ---help---
2676 This provides basic support for National Semiconductor's
2677 (now AMD's) Geode processors. The driver probes for the
2678 PCI-IDs of several on-chip devices, so its a good dependency
2679 for other scx200_* drivers.
2680
2681 If compiled as a module, the driver is named scx200.
2682
2683 config SCx200HR_TIMER
2684 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2685 depends on SCx200
2686 default y
2687 ---help---
2688 This driver provides a clocksource built upon the on-chip
2689 27MHz high-resolution timer. Its also a workaround for
2690 NSC Geode SC-1100's buggy TSC, which loses time when the
2691 processor goes idle (as is done by the scheduler). The
2692 other workaround is idle=poll boot option.
2693
2694 config OLPC
2695 bool "One Laptop Per Child support"
2696 depends on !X86_PAE
2697 select GPIOLIB
2698 select OF
2699 select OF_PROMTREE
2700 select IRQ_DOMAIN
2701 ---help---
2702 Add support for detecting the unique features of the OLPC
2703 XO hardware.
2704
2705 config OLPC_XO1_PM
2706 bool "OLPC XO-1 Power Management"
2707 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2708 ---help---
2709 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2710
2711 config OLPC_XO1_RTC
2712 bool "OLPC XO-1 Real Time Clock"
2713 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2714 ---help---
2715 Add support for the XO-1 real time clock, which can be used as a
2716 programmable wakeup source.
2717
2718 config OLPC_XO1_SCI
2719 bool "OLPC XO-1 SCI extras"
2720 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2721 depends on INPUT=y
2722 select POWER_SUPPLY
2723 ---help---
2724 Add support for SCI-based features of the OLPC XO-1 laptop:
2725 - EC-driven system wakeups
2726 - Power button
2727 - Ebook switch
2728 - Lid switch
2729 - AC adapter status updates
2730 - Battery status updates
2731
2732 config OLPC_XO15_SCI
2733 bool "OLPC XO-1.5 SCI extras"
2734 depends on OLPC && ACPI
2735 select POWER_SUPPLY
2736 ---help---
2737 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2738 - EC-driven system wakeups
2739 - AC adapter status updates
2740 - Battery status updates
2741
2742 config ALIX
2743 bool "PCEngines ALIX System Support (LED setup)"
2744 select GPIOLIB
2745 ---help---
2746 This option enables system support for the PCEngines ALIX.
2747 At present this just sets up LEDs for GPIO control on
2748 ALIX2/3/6 boards. However, other system specific setup should
2749 get added here.
2750
2751 Note: You must still enable the drivers for GPIO and LED support
2752 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2753
2754 Note: You have to set alix.force=1 for boards with Award BIOS.
2755
2756 config NET5501
2757 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2758 select GPIOLIB
2759 ---help---
2760 This option enables system support for the Soekris Engineering net5501.
2761
2762 config GEOS
2763 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2764 select GPIOLIB
2765 depends on DMI
2766 ---help---
2767 This option enables system support for the Traverse Technologies GEOS.
2768
2769 config TS5500
2770 bool "Technologic Systems TS-5500 platform support"
2771 depends on MELAN
2772 select CHECK_SIGNATURE
2773 select NEW_LEDS
2774 select LEDS_CLASS
2775 ---help---
2776 This option enables system support for the Technologic Systems TS-5500.
2777
2778 endif # X86_32
2779
2780 config AMD_NB
2781 def_bool y
2782 depends on CPU_SUP_AMD && PCI
2783
2784 config X86_SYSFB
2785 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2786 help
2787 Firmwares often provide initial graphics framebuffers so the BIOS,
2788 bootloader or kernel can show basic video-output during boot for
2789 user-guidance and debugging. Historically, x86 used the VESA BIOS
2790 Extensions and EFI-framebuffers for this, which are mostly limited
2791 to x86.
2792 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2793 framebuffers so the new generic system-framebuffer drivers can be
2794 used on x86. If the framebuffer is not compatible with the generic
2795 modes, it is advertised as fallback platform framebuffer so legacy
2796 drivers like efifb, vesafb and uvesafb can pick it up.
2797 If this option is not selected, all system framebuffers are always
2798 marked as fallback platform framebuffers as usual.
2799
2800 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2801 not be able to pick up generic system framebuffers if this option
2802 is selected. You are highly encouraged to enable simplefb as
2803 replacement if you select this option. simplefb can correctly deal
2804 with generic system framebuffers. But you should still keep vesafb
2805 and others enabled as fallback if a system framebuffer is
2806 incompatible with simplefb.
2807
2808 If unsure, say Y.
2809
2810 endmenu
2811
2812
2813 menu "Binary Emulations"
2814
2815 config IA32_EMULATION
2816 bool "IA32 Emulation"
2817 depends on X86_64
2818 select ARCH_WANT_OLD_COMPAT_IPC
2819 select BINFMT_ELF
2820 select COMPAT_BINFMT_ELF
2821 select COMPAT_OLD_SIGACTION
2822 ---help---
2823 Include code to run legacy 32-bit programs under a
2824 64-bit kernel. You should likely turn this on, unless you're
2825 100% sure that you don't have any 32-bit programs left.
2826
2827 config IA32_AOUT
2828 tristate "IA32 a.out support"
2829 depends on IA32_EMULATION
2830 depends on BROKEN
2831 ---help---
2832 Support old a.out binaries in the 32bit emulation.
2833
2834 config X86_X32
2835 bool "x32 ABI for 64-bit mode"
2836 depends on X86_64
2837 ---help---
2838 Include code to run binaries for the x32 native 32-bit ABI
2839 for 64-bit processors. An x32 process gets access to the
2840 full 64-bit register file and wide data path while leaving
2841 pointers at 32 bits for smaller memory footprint.
2842
2843 You will need a recent binutils (2.22 or later) with
2844 elf32_x86_64 support enabled to compile a kernel with this
2845 option set.
2846
2847 config COMPAT_32
2848 def_bool y
2849 depends on IA32_EMULATION || X86_32
2850 select HAVE_UID16
2851 select OLD_SIGSUSPEND3
2852
2853 config COMPAT
2854 def_bool y
2855 depends on IA32_EMULATION || X86_X32
2856
2857 if COMPAT
2858 config COMPAT_FOR_U64_ALIGNMENT
2859 def_bool y
2860
2861 config SYSVIPC_COMPAT
2862 def_bool y
2863 depends on SYSVIPC
2864 endif
2865
2866 endmenu
2867
2868
2869 config HAVE_ATOMIC_IOMAP
2870 def_bool y
2871 depends on X86_32
2872
2873 config X86_DEV_DMA_OPS
2874 bool
2875
2876 config HAVE_GENERIC_GUP
2877 def_bool y
2878
2879 source "drivers/firmware/Kconfig"
2880
2881 source "arch/x86/kvm/Kconfig"