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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_AOUT
18 select HAVE_GENERIC_DMA_COHERENT
19 select MODULES_USE_ELF_REL
20 select OLD_SIGACTION
21
22 config X86_64
23 def_bool y
24 depends on 64BIT
25 # Options that are inherently 64-bit kernel only:
26 select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
27 select ARCH_SUPPORTS_INT128
28 select ARCH_USE_CMPXCHG_LOCKREF
29 select HAVE_ARCH_SOFT_DIRTY
30 select MODULES_USE_ELF_RELA
31 select NEED_DMA_MAP_STATE
32 select SWIOTLB
33 select X86_DEV_DMA_OPS
34 select ARCH_HAS_SYSCALL_WRAPPER
35
36 #
37 # Arch settings
38 #
39 # ( Note that options that are marked 'if X86_64' could in principle be
40 # ported to 32-bit as well. )
41 #
42 config X86
43 def_bool y
44 #
45 # Note: keep this list sorted alphabetically
46 #
47 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
48 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
49 select ANON_INODES
50 select ARCH_CLOCKSOURCE_DATA
51 select ARCH_CLOCKSOURCE_INIT
52 select ARCH_DISCARD_MEMBLOCK
53 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
54 select ARCH_HAS_DEBUG_VIRTUAL
55 select ARCH_HAS_DEVMEM_IS_ALLOWED
56 select ARCH_HAS_ELF_RANDOMIZE
57 select ARCH_HAS_FAST_MULTIPLIER
58 select ARCH_HAS_FILTER_PGPROT
59 select ARCH_HAS_FORTIFY_SOURCE
60 select ARCH_HAS_GCOV_PROFILE_ALL
61 select ARCH_HAS_KCOV if X86_64
62 select ARCH_HAS_MEMBARRIER_SYNC_CORE
63 select ARCH_HAS_PMEM_API if X86_64
64 select ARCH_HAS_PTE_SPECIAL
65 select ARCH_HAS_REFCOUNT
66 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
67 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
68 select ARCH_HAS_SET_MEMORY
69 select ARCH_HAS_STRICT_KERNEL_RWX
70 select ARCH_HAS_STRICT_MODULE_RWX
71 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
72 select ARCH_HAS_UBSAN_SANITIZE_ALL
73 select ARCH_HAS_ZONE_DEVICE if X86_64
74 select ARCH_HAVE_NMI_SAFE_CMPXCHG
75 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
76 select ARCH_MIGHT_HAVE_PC_PARPORT
77 select ARCH_MIGHT_HAVE_PC_SERIO
78 select ARCH_SUPPORTS_ACPI
79 select ARCH_SUPPORTS_ATOMIC_RMW
80 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
81 select ARCH_USE_BUILTIN_BSWAP
82 select ARCH_USE_QUEUED_RWLOCKS
83 select ARCH_USE_QUEUED_SPINLOCKS
84 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
85 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
86 select ARCH_WANTS_THP_SWAP if X86_64
87 select BUILDTIME_EXTABLE_SORT
88 select CLKEVT_I8253
89 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
90 select CLOCKSOURCE_WATCHDOG
91 select DCACHE_WORD_ACCESS
92 select EDAC_ATOMIC_SCRUB
93 select EDAC_SUPPORT
94 select GENERIC_CLOCKEVENTS
95 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
96 select GENERIC_CLOCKEVENTS_MIN_ADJUST
97 select GENERIC_CMOS_UPDATE
98 select GENERIC_CPU_AUTOPROBE
99 select GENERIC_CPU_VULNERABILITIES
100 select GENERIC_EARLY_IOREMAP
101 select GENERIC_FIND_FIRST_BIT
102 select GENERIC_IOMAP
103 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
104 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
105 select GENERIC_IRQ_MIGRATION if SMP
106 select GENERIC_IRQ_PROBE
107 select GENERIC_IRQ_RESERVATION_MODE
108 select GENERIC_IRQ_SHOW
109 select GENERIC_PENDING_IRQ if SMP
110 select GENERIC_SMP_IDLE_THREAD
111 select GENERIC_STRNCPY_FROM_USER
112 select GENERIC_STRNLEN_USER
113 select GENERIC_TIME_VSYSCALL
114 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
115 select HAVE_ACPI_APEI if ACPI
116 select HAVE_ACPI_APEI_NMI if ACPI
117 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
118 select HAVE_ARCH_AUDITSYSCALL
119 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
120 select HAVE_ARCH_JUMP_LABEL
121 select HAVE_ARCH_JUMP_LABEL_RELATIVE
122 select HAVE_ARCH_KASAN if X86_64
123 select HAVE_ARCH_KGDB
124 select HAVE_ARCH_MMAP_RND_BITS if MMU
125 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
126 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
127 select HAVE_ARCH_PREL32_RELOCATIONS
128 select HAVE_ARCH_SECCOMP_FILTER
129 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
130 select HAVE_ARCH_STACKLEAK
131 select HAVE_ARCH_TRACEHOOK
132 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
133 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
134 select HAVE_ARCH_VMAP_STACK if X86_64
135 select HAVE_ARCH_WITHIN_STACK_FRAMES
136 select HAVE_CMPXCHG_DOUBLE
137 select HAVE_CMPXCHG_LOCAL
138 select HAVE_CONTEXT_TRACKING if X86_64
139 select HAVE_COPY_THREAD_TLS
140 select HAVE_C_RECORDMCOUNT
141 select HAVE_DEBUG_KMEMLEAK
142 select HAVE_DEBUG_STACKOVERFLOW
143 select HAVE_DMA_CONTIGUOUS
144 select HAVE_DYNAMIC_FTRACE
145 select HAVE_DYNAMIC_FTRACE_WITH_REGS
146 select HAVE_EBPF_JIT
147 select HAVE_EFFICIENT_UNALIGNED_ACCESS
148 select HAVE_EISA
149 select HAVE_EXIT_THREAD
150 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
151 select HAVE_FTRACE_MCOUNT_RECORD
152 select HAVE_FUNCTION_GRAPH_TRACER
153 select HAVE_FUNCTION_TRACER
154 select HAVE_GCC_PLUGINS
155 select HAVE_HW_BREAKPOINT
156 select HAVE_IDE
157 select HAVE_IOREMAP_PROT
158 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
159 select HAVE_IRQ_TIME_ACCOUNTING
160 select HAVE_KERNEL_BZIP2
161 select HAVE_KERNEL_GZIP
162 select HAVE_KERNEL_LZ4
163 select HAVE_KERNEL_LZMA
164 select HAVE_KERNEL_LZO
165 select HAVE_KERNEL_XZ
166 select HAVE_KPROBES
167 select HAVE_KPROBES_ON_FTRACE
168 select HAVE_FUNCTION_ERROR_INJECTION
169 select HAVE_KRETPROBES
170 select HAVE_KVM
171 select HAVE_LIVEPATCH if X86_64
172 select HAVE_MEMBLOCK_NODE_MAP
173 select HAVE_MIXED_BREAKPOINTS_REGS
174 select HAVE_MOD_ARCH_SPECIFIC
175 select HAVE_MOVE_PMD
176 select HAVE_NMI
177 select HAVE_OPROFILE
178 select HAVE_OPTPROBES
179 select HAVE_PCSPKR_PLATFORM
180 select HAVE_PERF_EVENTS
181 select HAVE_PERF_EVENTS_NMI
182 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
183 select HAVE_PCI
184 select HAVE_PERF_REGS
185 select HAVE_PERF_USER_STACK_DUMP
186 select HAVE_RCU_TABLE_FREE if PARAVIRT
187 select HAVE_RCU_TABLE_INVALIDATE if HAVE_RCU_TABLE_FREE
188 select HAVE_REGS_AND_STACK_ACCESS_API
189 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
190 select HAVE_FUNCTION_ARG_ACCESS_API
191 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
192 select HAVE_STACK_VALIDATION if X86_64
193 select HAVE_RSEQ
194 select HAVE_SYSCALL_TRACEPOINTS
195 select HAVE_UNSTABLE_SCHED_CLOCK
196 select HAVE_USER_RETURN_NOTIFIER
197 select HOTPLUG_SMT if SMP
198 select IRQ_FORCED_THREADING
199 select NEED_SG_DMA_LENGTH
200 select PCI_DOMAINS if PCI
201 select PCI_LOCKLESS_CONFIG if PCI
202 select PERF_EVENTS
203 select RTC_LIB
204 select RTC_MC146818_LIB
205 select SPARSE_IRQ
206 select SRCU
207 select SYSCTL_EXCEPTION_TRACE
208 select THREAD_INFO_IN_TASK
209 select USER_STACKTRACE_SUPPORT
210 select VIRT_TO_BUS
211 select X86_FEATURE_NAMES if PROC_FS
212
213 config INSTRUCTION_DECODER
214 def_bool y
215 depends on KPROBES || PERF_EVENTS || UPROBES
216
217 config OUTPUT_FORMAT
218 string
219 default "elf32-i386" if X86_32
220 default "elf64-x86-64" if X86_64
221
222 config ARCH_DEFCONFIG
223 string
224 default "arch/x86/configs/i386_defconfig" if X86_32
225 default "arch/x86/configs/x86_64_defconfig" if X86_64
226
227 config LOCKDEP_SUPPORT
228 def_bool y
229
230 config STACKTRACE_SUPPORT
231 def_bool y
232
233 config MMU
234 def_bool y
235
236 config ARCH_MMAP_RND_BITS_MIN
237 default 28 if 64BIT
238 default 8
239
240 config ARCH_MMAP_RND_BITS_MAX
241 default 32 if 64BIT
242 default 16
243
244 config ARCH_MMAP_RND_COMPAT_BITS_MIN
245 default 8
246
247 config ARCH_MMAP_RND_COMPAT_BITS_MAX
248 default 16
249
250 config SBUS
251 bool
252
253 config GENERIC_ISA_DMA
254 def_bool y
255 depends on ISA_DMA_API
256
257 config GENERIC_BUG
258 def_bool y
259 depends on BUG
260 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
261
262 config GENERIC_BUG_RELATIVE_POINTERS
263 bool
264
265 config GENERIC_HWEIGHT
266 def_bool y
267
268 config ARCH_MAY_HAVE_PC_FDC
269 def_bool y
270 depends on ISA_DMA_API
271
272 config RWSEM_XCHGADD_ALGORITHM
273 def_bool y
274
275 config GENERIC_CALIBRATE_DELAY
276 def_bool y
277
278 config ARCH_HAS_CPU_RELAX
279 def_bool y
280
281 config ARCH_HAS_CACHE_LINE_SIZE
282 def_bool y
283
284 config ARCH_HAS_FILTER_PGPROT
285 def_bool y
286
287 config HAVE_SETUP_PER_CPU_AREA
288 def_bool y
289
290 config NEED_PER_CPU_EMBED_FIRST_CHUNK
291 def_bool y
292
293 config NEED_PER_CPU_PAGE_FIRST_CHUNK
294 def_bool y
295
296 config ARCH_HIBERNATION_POSSIBLE
297 def_bool y
298
299 config ARCH_SUSPEND_POSSIBLE
300 def_bool y
301
302 config ARCH_WANT_HUGE_PMD_SHARE
303 def_bool y
304
305 config ARCH_WANT_GENERAL_HUGETLB
306 def_bool y
307
308 config ZONE_DMA32
309 def_bool y if X86_64
310
311 config AUDIT_ARCH
312 def_bool y if X86_64
313
314 config ARCH_SUPPORTS_OPTIMIZED_INLINING
315 def_bool y
316
317 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
318 def_bool y
319
320 config KASAN_SHADOW_OFFSET
321 hex
322 depends on KASAN
323 default 0xdffffc0000000000
324
325 config HAVE_INTEL_TXT
326 def_bool y
327 depends on INTEL_IOMMU && ACPI
328
329 config X86_32_SMP
330 def_bool y
331 depends on X86_32 && SMP
332
333 config X86_64_SMP
334 def_bool y
335 depends on X86_64 && SMP
336
337 config X86_32_LAZY_GS
338 def_bool y
339 depends on X86_32 && !STACKPROTECTOR
340
341 config ARCH_SUPPORTS_UPROBES
342 def_bool y
343
344 config FIX_EARLYCON_MEM
345 def_bool y
346
347 config DYNAMIC_PHYSICAL_MASK
348 bool
349
350 config PGTABLE_LEVELS
351 int
352 default 5 if X86_5LEVEL
353 default 4 if X86_64
354 default 3 if X86_PAE
355 default 2
356
357 config CC_HAS_SANE_STACKPROTECTOR
358 bool
359 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
360 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
361 help
362 We have to make sure stack protector is unconditionally disabled if
363 the compiler produces broken code.
364
365 menu "Processor type and features"
366
367 config ZONE_DMA
368 bool "DMA memory allocation support" if EXPERT
369 default y
370 help
371 DMA memory allocation support allows devices with less than 32-bit
372 addressing to allocate within the first 16MB of address space.
373 Disable if no such devices will be used.
374
375 If unsure, say Y.
376
377 config SMP
378 bool "Symmetric multi-processing support"
379 ---help---
380 This enables support for systems with more than one CPU. If you have
381 a system with only one CPU, say N. If you have a system with more
382 than one CPU, say Y.
383
384 If you say N here, the kernel will run on uni- and multiprocessor
385 machines, but will use only one CPU of a multiprocessor machine. If
386 you say Y here, the kernel will run on many, but not all,
387 uniprocessor machines. On a uniprocessor machine, the kernel
388 will run faster if you say N here.
389
390 Note that if you say Y here and choose architecture "586" or
391 "Pentium" under "Processor family", the kernel will not work on 486
392 architectures. Similarly, multiprocessor kernels for the "PPro"
393 architecture may not work on all Pentium based boards.
394
395 People using multiprocessor machines who say Y here should also say
396 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
397 Management" code will be disabled if you say Y here.
398
399 See also <file:Documentation/x86/i386/IO-APIC.txt>,
400 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
401 <http://www.tldp.org/docs.html#howto>.
402
403 If you don't know what to do here, say N.
404
405 config X86_FEATURE_NAMES
406 bool "Processor feature human-readable names" if EMBEDDED
407 default y
408 ---help---
409 This option compiles in a table of x86 feature bits and corresponding
410 names. This is required to support /proc/cpuinfo and a few kernel
411 messages. You can disable this to save space, at the expense of
412 making those few kernel messages show numeric feature bits instead.
413
414 If in doubt, say Y.
415
416 config X86_X2APIC
417 bool "Support x2apic"
418 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
419 ---help---
420 This enables x2apic support on CPUs that have this feature.
421
422 This allows 32-bit apic IDs (so it can support very large systems),
423 and accesses the local apic via MSRs not via mmio.
424
425 If you don't know what to do here, say N.
426
427 config X86_MPPARSE
428 bool "Enable MPS table" if ACPI || SFI
429 default y
430 depends on X86_LOCAL_APIC
431 ---help---
432 For old smp systems that do not have proper acpi support. Newer systems
433 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
434
435 config GOLDFISH
436 def_bool y
437 depends on X86_GOLDFISH
438
439 config RETPOLINE
440 bool "Avoid speculative indirect branches in kernel"
441 default y
442 select STACK_VALIDATION if HAVE_STACK_VALIDATION
443 help
444 Compile kernel with the retpoline compiler options to guard against
445 kernel-to-user data leaks by avoiding speculative indirect
446 branches. Requires a compiler with -mindirect-branch=thunk-extern
447 support for full protection. The kernel may run slower.
448
449 config X86_RESCTRL
450 bool "Resource Control support"
451 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
452 select KERNFS
453 help
454 Enable Resource Control support.
455
456 Provide support for the allocation and monitoring of system resources
457 usage by the CPU.
458
459 Intel calls this Intel Resource Director Technology
460 (Intel(R) RDT). More information about RDT can be found in the
461 Intel x86 Architecture Software Developer Manual.
462
463 AMD calls this AMD Platform Quality of Service (AMD QoS).
464 More information about AMD QoS can be found in the AMD64 Technology
465 Platform Quality of Service Extensions manual.
466
467 Say N if unsure.
468
469 if X86_32
470 config X86_BIGSMP
471 bool "Support for big SMP systems with more than 8 CPUs"
472 depends on SMP
473 ---help---
474 This option is needed for the systems that have more than 8 CPUs
475
476 config X86_EXTENDED_PLATFORM
477 bool "Support for extended (non-PC) x86 platforms"
478 default y
479 ---help---
480 If you disable this option then the kernel will only support
481 standard PC platforms. (which covers the vast majority of
482 systems out there.)
483
484 If you enable this option then you'll be able to select support
485 for the following (non-PC) 32 bit x86 platforms:
486 Goldfish (Android emulator)
487 AMD Elan
488 RDC R-321x SoC
489 SGI 320/540 (Visual Workstation)
490 STA2X11-based (e.g. Northville)
491 Moorestown MID devices
492
493 If you have one of these systems, or if you want to build a
494 generic distribution kernel, say Y here - otherwise say N.
495 endif
496
497 if X86_64
498 config X86_EXTENDED_PLATFORM
499 bool "Support for extended (non-PC) x86 platforms"
500 default y
501 ---help---
502 If you disable this option then the kernel will only support
503 standard PC platforms. (which covers the vast majority of
504 systems out there.)
505
506 If you enable this option then you'll be able to select support
507 for the following (non-PC) 64 bit x86 platforms:
508 Numascale NumaChip
509 ScaleMP vSMP
510 SGI Ultraviolet
511
512 If you have one of these systems, or if you want to build a
513 generic distribution kernel, say Y here - otherwise say N.
514 endif
515 # This is an alphabetically sorted list of 64 bit extended platforms
516 # Please maintain the alphabetic order if and when there are additions
517 config X86_NUMACHIP
518 bool "Numascale NumaChip"
519 depends on X86_64
520 depends on X86_EXTENDED_PLATFORM
521 depends on NUMA
522 depends on SMP
523 depends on X86_X2APIC
524 depends on PCI_MMCONFIG
525 ---help---
526 Adds support for Numascale NumaChip large-SMP systems. Needed to
527 enable more than ~168 cores.
528 If you don't have one of these, you should say N here.
529
530 config X86_VSMP
531 bool "ScaleMP vSMP"
532 select HYPERVISOR_GUEST
533 select PARAVIRT
534 depends on X86_64 && PCI
535 depends on X86_EXTENDED_PLATFORM
536 depends on SMP
537 ---help---
538 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
539 supposed to run on these EM64T-based machines. Only choose this option
540 if you have one of these machines.
541
542 config X86_UV
543 bool "SGI Ultraviolet"
544 depends on X86_64
545 depends on X86_EXTENDED_PLATFORM
546 depends on NUMA
547 depends on EFI
548 depends on X86_X2APIC
549 depends on PCI
550 ---help---
551 This option is needed in order to support SGI Ultraviolet systems.
552 If you don't have one of these, you should say N here.
553
554 # Following is an alphabetically sorted list of 32 bit extended platforms
555 # Please maintain the alphabetic order if and when there are additions
556
557 config X86_GOLDFISH
558 bool "Goldfish (Virtual Platform)"
559 depends on X86_EXTENDED_PLATFORM
560 ---help---
561 Enable support for the Goldfish virtual platform used primarily
562 for Android development. Unless you are building for the Android
563 Goldfish emulator say N here.
564
565 config X86_INTEL_CE
566 bool "CE4100 TV platform"
567 depends on PCI
568 depends on PCI_GODIRECT
569 depends on X86_IO_APIC
570 depends on X86_32
571 depends on X86_EXTENDED_PLATFORM
572 select X86_REBOOTFIXUPS
573 select OF
574 select OF_EARLY_FLATTREE
575 ---help---
576 Select for the Intel CE media processor (CE4100) SOC.
577 This option compiles in support for the CE4100 SOC for settop
578 boxes and media devices.
579
580 config X86_INTEL_MID
581 bool "Intel MID platform support"
582 depends on X86_EXTENDED_PLATFORM
583 depends on X86_PLATFORM_DEVICES
584 depends on PCI
585 depends on X86_64 || (PCI_GOANY && X86_32)
586 depends on X86_IO_APIC
587 select SFI
588 select I2C
589 select DW_APB_TIMER
590 select APB_TIMER
591 select INTEL_SCU_IPC
592 select MFD_INTEL_MSIC
593 ---help---
594 Select to build a kernel capable of supporting Intel MID (Mobile
595 Internet Device) platform systems which do not have the PCI legacy
596 interfaces. If you are building for a PC class system say N here.
597
598 Intel MID platforms are based on an Intel processor and chipset which
599 consume less power than most of the x86 derivatives.
600
601 config X86_INTEL_QUARK
602 bool "Intel Quark platform support"
603 depends on X86_32
604 depends on X86_EXTENDED_PLATFORM
605 depends on X86_PLATFORM_DEVICES
606 depends on X86_TSC
607 depends on PCI
608 depends on PCI_GOANY
609 depends on X86_IO_APIC
610 select IOSF_MBI
611 select INTEL_IMR
612 select COMMON_CLK
613 ---help---
614 Select to include support for Quark X1000 SoC.
615 Say Y here if you have a Quark based system such as the Arduino
616 compatible Intel Galileo.
617
618 config X86_INTEL_LPSS
619 bool "Intel Low Power Subsystem Support"
620 depends on X86 && ACPI && PCI
621 select COMMON_CLK
622 select PINCTRL
623 select IOSF_MBI
624 ---help---
625 Select to build support for Intel Low Power Subsystem such as
626 found on Intel Lynxpoint PCH. Selecting this option enables
627 things like clock tree (common clock framework) and pincontrol
628 which are needed by the LPSS peripheral drivers.
629
630 config X86_AMD_PLATFORM_DEVICE
631 bool "AMD ACPI2Platform devices support"
632 depends on ACPI
633 select COMMON_CLK
634 select PINCTRL
635 ---help---
636 Select to interpret AMD specific ACPI device to platform device
637 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
638 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
639 implemented under PINCTRL subsystem.
640
641 config IOSF_MBI
642 tristate "Intel SoC IOSF Sideband support for SoC platforms"
643 depends on PCI
644 ---help---
645 This option enables sideband register access support for Intel SoC
646 platforms. On these platforms the IOSF sideband is used in lieu of
647 MSR's for some register accesses, mostly but not limited to thermal
648 and power. Drivers may query the availability of this device to
649 determine if they need the sideband in order to work on these
650 platforms. The sideband is available on the following SoC products.
651 This list is not meant to be exclusive.
652 - BayTrail
653 - Braswell
654 - Quark
655
656 You should say Y if you are running a kernel on one of these SoC's.
657
658 config IOSF_MBI_DEBUG
659 bool "Enable IOSF sideband access through debugfs"
660 depends on IOSF_MBI && DEBUG_FS
661 ---help---
662 Select this option to expose the IOSF sideband access registers (MCR,
663 MDR, MCRX) through debugfs to write and read register information from
664 different units on the SoC. This is most useful for obtaining device
665 state information for debug and analysis. As this is a general access
666 mechanism, users of this option would have specific knowledge of the
667 device they want to access.
668
669 If you don't require the option or are in doubt, say N.
670
671 config X86_RDC321X
672 bool "RDC R-321x SoC"
673 depends on X86_32
674 depends on X86_EXTENDED_PLATFORM
675 select M486
676 select X86_REBOOTFIXUPS
677 ---help---
678 This option is needed for RDC R-321x system-on-chip, also known
679 as R-8610-(G).
680 If you don't have one of these chips, you should say N here.
681
682 config X86_32_NON_STANDARD
683 bool "Support non-standard 32-bit SMP architectures"
684 depends on X86_32 && SMP
685 depends on X86_EXTENDED_PLATFORM
686 ---help---
687 This option compiles in the bigsmp and STA2X11 default
688 subarchitectures. It is intended for a generic binary
689 kernel. If you select them all, kernel will probe it one by
690 one and will fallback to default.
691
692 # Alphabetically sorted list of Non standard 32 bit platforms
693
694 config X86_SUPPORTS_MEMORY_FAILURE
695 def_bool y
696 # MCE code calls memory_failure():
697 depends on X86_MCE
698 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
699 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
700 depends on X86_64 || !SPARSEMEM
701 select ARCH_SUPPORTS_MEMORY_FAILURE
702
703 config STA2X11
704 bool "STA2X11 Companion Chip Support"
705 depends on X86_32_NON_STANDARD && PCI
706 select ARCH_HAS_PHYS_TO_DMA
707 select X86_DEV_DMA_OPS
708 select X86_DMA_REMAP
709 select SWIOTLB
710 select MFD_STA2X11
711 select GPIOLIB
712 ---help---
713 This adds support for boards based on the STA2X11 IO-Hub,
714 a.k.a. "ConneXt". The chip is used in place of the standard
715 PC chipset, so all "standard" peripherals are missing. If this
716 option is selected the kernel will still be able to boot on
717 standard PC machines.
718
719 config X86_32_IRIS
720 tristate "Eurobraille/Iris poweroff module"
721 depends on X86_32
722 ---help---
723 The Iris machines from EuroBraille do not have APM or ACPI support
724 to shut themselves down properly. A special I/O sequence is
725 needed to do so, which is what this module does at
726 kernel shutdown.
727
728 This is only for Iris machines from EuroBraille.
729
730 If unused, say N.
731
732 config SCHED_OMIT_FRAME_POINTER
733 def_bool y
734 prompt "Single-depth WCHAN output"
735 depends on X86
736 ---help---
737 Calculate simpler /proc/<PID>/wchan values. If this option
738 is disabled then wchan values will recurse back to the
739 caller function. This provides more accurate wchan values,
740 at the expense of slightly more scheduling overhead.
741
742 If in doubt, say "Y".
743
744 menuconfig HYPERVISOR_GUEST
745 bool "Linux guest support"
746 ---help---
747 Say Y here to enable options for running Linux under various hyper-
748 visors. This option enables basic hypervisor detection and platform
749 setup.
750
751 If you say N, all options in this submenu will be skipped and
752 disabled, and Linux guest support won't be built in.
753
754 if HYPERVISOR_GUEST
755
756 config PARAVIRT
757 bool "Enable paravirtualization code"
758 ---help---
759 This changes the kernel so it can modify itself when it is run
760 under a hypervisor, potentially improving performance significantly
761 over full virtualization. However, when run without a hypervisor
762 the kernel is theoretically slower and slightly larger.
763
764 config PARAVIRT_XXL
765 bool
766
767 config PARAVIRT_DEBUG
768 bool "paravirt-ops debugging"
769 depends on PARAVIRT && DEBUG_KERNEL
770 ---help---
771 Enable to debug paravirt_ops internals. Specifically, BUG if
772 a paravirt_op is missing when it is called.
773
774 config PARAVIRT_SPINLOCKS
775 bool "Paravirtualization layer for spinlocks"
776 depends on PARAVIRT && SMP
777 ---help---
778 Paravirtualized spinlocks allow a pvops backend to replace the
779 spinlock implementation with something virtualization-friendly
780 (for example, block the virtual CPU rather than spinning).
781
782 It has a minimal impact on native kernels and gives a nice performance
783 benefit on paravirtualized KVM / Xen kernels.
784
785 If you are unsure how to answer this question, answer Y.
786
787 config QUEUED_LOCK_STAT
788 bool "Paravirt queued spinlock statistics"
789 depends on PARAVIRT_SPINLOCKS && DEBUG_FS
790 ---help---
791 Enable the collection of statistical data on the slowpath
792 behavior of paravirtualized queued spinlocks and report
793 them on debugfs.
794
795 source "arch/x86/xen/Kconfig"
796
797 config KVM_GUEST
798 bool "KVM Guest support (including kvmclock)"
799 depends on PARAVIRT
800 select PARAVIRT_CLOCK
801 default y
802 ---help---
803 This option enables various optimizations for running under the KVM
804 hypervisor. It includes a paravirtualized clock, so that instead
805 of relying on a PIT (or probably other) emulation by the
806 underlying device model, the host provides the guest with
807 timing infrastructure such as time of day, and system time
808
809 config PVH
810 bool "Support for running PVH guests"
811 ---help---
812 This option enables the PVH entry point for guest virtual machines
813 as specified in the x86/HVM direct boot ABI.
814
815 config KVM_DEBUG_FS
816 bool "Enable debug information for KVM Guests in debugfs"
817 depends on KVM_GUEST && DEBUG_FS
818 ---help---
819 This option enables collection of various statistics for KVM guest.
820 Statistics are displayed in debugfs filesystem. Enabling this option
821 may incur significant overhead.
822
823 config PARAVIRT_TIME_ACCOUNTING
824 bool "Paravirtual steal time accounting"
825 depends on PARAVIRT
826 ---help---
827 Select this option to enable fine granularity task steal time
828 accounting. Time spent executing other tasks in parallel with
829 the current vCPU is discounted from the vCPU power. To account for
830 that, there can be a small performance impact.
831
832 If in doubt, say N here.
833
834 config PARAVIRT_CLOCK
835 bool
836
837 config JAILHOUSE_GUEST
838 bool "Jailhouse non-root cell support"
839 depends on X86_64 && PCI
840 select X86_PM_TIMER
841 ---help---
842 This option allows to run Linux as guest in a Jailhouse non-root
843 cell. You can leave this option disabled if you only want to start
844 Jailhouse and run Linux afterwards in the root cell.
845
846 endif #HYPERVISOR_GUEST
847
848 source "arch/x86/Kconfig.cpu"
849
850 config HPET_TIMER
851 def_bool X86_64
852 prompt "HPET Timer Support" if X86_32
853 ---help---
854 Use the IA-PC HPET (High Precision Event Timer) to manage
855 time in preference to the PIT and RTC, if a HPET is
856 present.
857 HPET is the next generation timer replacing legacy 8254s.
858 The HPET provides a stable time base on SMP
859 systems, unlike the TSC, but it is more expensive to access,
860 as it is off-chip. The interface used is documented
861 in the HPET spec, revision 1.
862
863 You can safely choose Y here. However, HPET will only be
864 activated if the platform and the BIOS support this feature.
865 Otherwise the 8254 will be used for timing services.
866
867 Choose N to continue using the legacy 8254 timer.
868
869 config HPET_EMULATE_RTC
870 def_bool y
871 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
872
873 config APB_TIMER
874 def_bool y if X86_INTEL_MID
875 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
876 select DW_APB_TIMER
877 depends on X86_INTEL_MID && SFI
878 help
879 APB timer is the replacement for 8254, HPET on X86 MID platforms.
880 The APBT provides a stable time base on SMP
881 systems, unlike the TSC, but it is more expensive to access,
882 as it is off-chip. APB timers are always running regardless of CPU
883 C states, they are used as per CPU clockevent device when possible.
884
885 # Mark as expert because too many people got it wrong.
886 # The code disables itself when not needed.
887 config DMI
888 default y
889 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
890 bool "Enable DMI scanning" if EXPERT
891 ---help---
892 Enabled scanning of DMI to identify machine quirks. Say Y
893 here unless you have verified that your setup is not
894 affected by entries in the DMI blacklist. Required by PNP
895 BIOS code.
896
897 config GART_IOMMU
898 bool "Old AMD GART IOMMU support"
899 select IOMMU_HELPER
900 select SWIOTLB
901 depends on X86_64 && PCI && AMD_NB
902 ---help---
903 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
904 GART based hardware IOMMUs.
905
906 The GART supports full DMA access for devices with 32-bit access
907 limitations, on systems with more than 3 GB. This is usually needed
908 for USB, sound, many IDE/SATA chipsets and some other devices.
909
910 Newer systems typically have a modern AMD IOMMU, supported via
911 the CONFIG_AMD_IOMMU=y config option.
912
913 In normal configurations this driver is only active when needed:
914 there's more than 3 GB of memory and the system contains a
915 32-bit limited device.
916
917 If unsure, say Y.
918
919 config CALGARY_IOMMU
920 bool "IBM Calgary IOMMU support"
921 select IOMMU_HELPER
922 select SWIOTLB
923 depends on X86_64 && PCI
924 ---help---
925 Support for hardware IOMMUs in IBM's xSeries x366 and x460
926 systems. Needed to run systems with more than 3GB of memory
927 properly with 32-bit PCI devices that do not support DAC
928 (Double Address Cycle). Calgary also supports bus level
929 isolation, where all DMAs pass through the IOMMU. This
930 prevents them from going anywhere except their intended
931 destination. This catches hard-to-find kernel bugs and
932 mis-behaving drivers and devices that do not use the DMA-API
933 properly to set up their DMA buffers. The IOMMU can be
934 turned off at boot time with the iommu=off parameter.
935 Normally the kernel will make the right choice by itself.
936 If unsure, say Y.
937
938 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
939 def_bool y
940 prompt "Should Calgary be enabled by default?"
941 depends on CALGARY_IOMMU
942 ---help---
943 Should Calgary be enabled by default? if you choose 'y', Calgary
944 will be used (if it exists). If you choose 'n', Calgary will not be
945 used even if it exists. If you choose 'n' and would like to use
946 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
947 If unsure, say Y.
948
949 config MAXSMP
950 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
951 depends on X86_64 && SMP && DEBUG_KERNEL
952 select CPUMASK_OFFSTACK
953 ---help---
954 Enable maximum number of CPUS and NUMA Nodes for this architecture.
955 If unsure, say N.
956
957 #
958 # The maximum number of CPUs supported:
959 #
960 # The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
961 # and which can be configured interactively in the
962 # [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
963 #
964 # The ranges are different on 32-bit and 64-bit kernels, depending on
965 # hardware capabilities and scalability features of the kernel.
966 #
967 # ( If MAXSMP is enabled we just use the highest possible value and disable
968 # interactive configuration. )
969 #
970
971 config NR_CPUS_RANGE_BEGIN
972 int
973 default NR_CPUS_RANGE_END if MAXSMP
974 default 1 if !SMP
975 default 2
976
977 config NR_CPUS_RANGE_END
978 int
979 depends on X86_32
980 default 64 if SMP && X86_BIGSMP
981 default 8 if SMP && !X86_BIGSMP
982 default 1 if !SMP
983
984 config NR_CPUS_RANGE_END
985 int
986 depends on X86_64
987 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK)
988 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
989 default 1 if !SMP
990
991 config NR_CPUS_DEFAULT
992 int
993 depends on X86_32
994 default 32 if X86_BIGSMP
995 default 8 if SMP
996 default 1 if !SMP
997
998 config NR_CPUS_DEFAULT
999 int
1000 depends on X86_64
1001 default 8192 if MAXSMP
1002 default 64 if SMP
1003 default 1 if !SMP
1004
1005 config NR_CPUS
1006 int "Maximum number of CPUs" if SMP && !MAXSMP
1007 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1008 default NR_CPUS_DEFAULT
1009 ---help---
1010 This allows you to specify the maximum number of CPUs which this
1011 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
1012 supported value is 8192, otherwise the maximum value is 512. The
1013 minimum value which makes sense is 2.
1014
1015 This is purely to save memory: each supported CPU adds about 8KB
1016 to the kernel image.
1017
1018 config SCHED_SMT
1019 def_bool y if SMP
1020
1021 config SCHED_MC
1022 def_bool y
1023 prompt "Multi-core scheduler support"
1024 depends on SMP
1025 ---help---
1026 Multi-core scheduler support improves the CPU scheduler's decision
1027 making when dealing with multi-core CPU chips at a cost of slightly
1028 increased overhead in some places. If unsure say N here.
1029
1030 config SCHED_MC_PRIO
1031 bool "CPU core priorities scheduler support"
1032 depends on SCHED_MC && CPU_SUP_INTEL
1033 select X86_INTEL_PSTATE
1034 select CPU_FREQ
1035 default y
1036 ---help---
1037 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1038 core ordering determined at manufacturing time, which allows
1039 certain cores to reach higher turbo frequencies (when running
1040 single threaded workloads) than others.
1041
1042 Enabling this kernel feature teaches the scheduler about
1043 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1044 scheduler's CPU selection logic accordingly, so that higher
1045 overall system performance can be achieved.
1046
1047 This feature will have no effect on CPUs without this feature.
1048
1049 If unsure say Y here.
1050
1051 config UP_LATE_INIT
1052 def_bool y
1053 depends on !SMP && X86_LOCAL_APIC
1054
1055 config X86_UP_APIC
1056 bool "Local APIC support on uniprocessors" if !PCI_MSI
1057 default PCI_MSI
1058 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1059 ---help---
1060 A local APIC (Advanced Programmable Interrupt Controller) is an
1061 integrated interrupt controller in the CPU. If you have a single-CPU
1062 system which has a processor with a local APIC, you can say Y here to
1063 enable and use it. If you say Y here even though your machine doesn't
1064 have a local APIC, then the kernel will still run with no slowdown at
1065 all. The local APIC supports CPU-generated self-interrupts (timer,
1066 performance counters), and the NMI watchdog which detects hard
1067 lockups.
1068
1069 config X86_UP_IOAPIC
1070 bool "IO-APIC support on uniprocessors"
1071 depends on X86_UP_APIC
1072 ---help---
1073 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1074 SMP-capable replacement for PC-style interrupt controllers. Most
1075 SMP systems and many recent uniprocessor systems have one.
1076
1077 If you have a single-CPU system with an IO-APIC, you can say Y here
1078 to use it. If you say Y here even though your machine doesn't have
1079 an IO-APIC, then the kernel will still run with no slowdown at all.
1080
1081 config X86_LOCAL_APIC
1082 def_bool y
1083 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1084 select IRQ_DOMAIN_HIERARCHY
1085 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1086
1087 config X86_IO_APIC
1088 def_bool y
1089 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1090
1091 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1092 bool "Reroute for broken boot IRQs"
1093 depends on X86_IO_APIC
1094 ---help---
1095 This option enables a workaround that fixes a source of
1096 spurious interrupts. This is recommended when threaded
1097 interrupt handling is used on systems where the generation of
1098 superfluous "boot interrupts" cannot be disabled.
1099
1100 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1101 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1102 kernel does during interrupt handling). On chipsets where this
1103 boot IRQ generation cannot be disabled, this workaround keeps
1104 the original IRQ line masked so that only the equivalent "boot
1105 IRQ" is delivered to the CPUs. The workaround also tells the
1106 kernel to set up the IRQ handler on the boot IRQ line. In this
1107 way only one interrupt is delivered to the kernel. Otherwise
1108 the spurious second interrupt may cause the kernel to bring
1109 down (vital) interrupt lines.
1110
1111 Only affects "broken" chipsets. Interrupt sharing may be
1112 increased on these systems.
1113
1114 config X86_MCE
1115 bool "Machine Check / overheating reporting"
1116 select GENERIC_ALLOCATOR
1117 default y
1118 ---help---
1119 Machine Check support allows the processor to notify the
1120 kernel if it detects a problem (e.g. overheating, data corruption).
1121 The action the kernel takes depends on the severity of the problem,
1122 ranging from warning messages to halting the machine.
1123
1124 config X86_MCELOG_LEGACY
1125 bool "Support for deprecated /dev/mcelog character device"
1126 depends on X86_MCE
1127 ---help---
1128 Enable support for /dev/mcelog which is needed by the old mcelog
1129 userspace logging daemon. Consider switching to the new generation
1130 rasdaemon solution.
1131
1132 config X86_MCE_INTEL
1133 def_bool y
1134 prompt "Intel MCE features"
1135 depends on X86_MCE && X86_LOCAL_APIC
1136 ---help---
1137 Additional support for intel specific MCE features such as
1138 the thermal monitor.
1139
1140 config X86_MCE_AMD
1141 def_bool y
1142 prompt "AMD MCE features"
1143 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1144 ---help---
1145 Additional support for AMD specific MCE features such as
1146 the DRAM Error Threshold.
1147
1148 config X86_ANCIENT_MCE
1149 bool "Support for old Pentium 5 / WinChip machine checks"
1150 depends on X86_32 && X86_MCE
1151 ---help---
1152 Include support for machine check handling on old Pentium 5 or WinChip
1153 systems. These typically need to be enabled explicitly on the command
1154 line.
1155
1156 config X86_MCE_THRESHOLD
1157 depends on X86_MCE_AMD || X86_MCE_INTEL
1158 def_bool y
1159
1160 config X86_MCE_INJECT
1161 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1162 tristate "Machine check injector support"
1163 ---help---
1164 Provide support for injecting machine checks for testing purposes.
1165 If you don't know what a machine check is and you don't do kernel
1166 QA it is safe to say n.
1167
1168 config X86_THERMAL_VECTOR
1169 def_bool y
1170 depends on X86_MCE_INTEL
1171
1172 source "arch/x86/events/Kconfig"
1173
1174 config X86_LEGACY_VM86
1175 bool "Legacy VM86 support"
1176 depends on X86_32
1177 ---help---
1178 This option allows user programs to put the CPU into V8086
1179 mode, which is an 80286-era approximation of 16-bit real mode.
1180
1181 Some very old versions of X and/or vbetool require this option
1182 for user mode setting. Similarly, DOSEMU will use it if
1183 available to accelerate real mode DOS programs. However, any
1184 recent version of DOSEMU, X, or vbetool should be fully
1185 functional even without kernel VM86 support, as they will all
1186 fall back to software emulation. Nevertheless, if you are using
1187 a 16-bit DOS program where 16-bit performance matters, vm86
1188 mode might be faster than emulation and you might want to
1189 enable this option.
1190
1191 Note that any app that works on a 64-bit kernel is unlikely to
1192 need this option, as 64-bit kernels don't, and can't, support
1193 V8086 mode. This option is also unrelated to 16-bit protected
1194 mode and is not needed to run most 16-bit programs under Wine.
1195
1196 Enabling this option increases the complexity of the kernel
1197 and slows down exception handling a tiny bit.
1198
1199 If unsure, say N here.
1200
1201 config VM86
1202 bool
1203 default X86_LEGACY_VM86
1204
1205 config X86_16BIT
1206 bool "Enable support for 16-bit segments" if EXPERT
1207 default y
1208 depends on MODIFY_LDT_SYSCALL
1209 ---help---
1210 This option is required by programs like Wine to run 16-bit
1211 protected mode legacy code on x86 processors. Disabling
1212 this option saves about 300 bytes on i386, or around 6K text
1213 plus 16K runtime memory on x86-64,
1214
1215 config X86_ESPFIX32
1216 def_bool y
1217 depends on X86_16BIT && X86_32
1218
1219 config X86_ESPFIX64
1220 def_bool y
1221 depends on X86_16BIT && X86_64
1222
1223 config X86_VSYSCALL_EMULATION
1224 bool "Enable vsyscall emulation" if EXPERT
1225 default y
1226 depends on X86_64
1227 ---help---
1228 This enables emulation of the legacy vsyscall page. Disabling
1229 it is roughly equivalent to booting with vsyscall=none, except
1230 that it will also disable the helpful warning if a program
1231 tries to use a vsyscall. With this option set to N, offending
1232 programs will just segfault, citing addresses of the form
1233 0xffffffffff600?00.
1234
1235 This option is required by many programs built before 2013, and
1236 care should be used even with newer programs if set to N.
1237
1238 Disabling this option saves about 7K of kernel size and
1239 possibly 4K of additional runtime pagetable memory.
1240
1241 config TOSHIBA
1242 tristate "Toshiba Laptop support"
1243 depends on X86_32
1244 ---help---
1245 This adds a driver to safely access the System Management Mode of
1246 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1247 not work on models with a Phoenix BIOS. The System Management Mode
1248 is used to set the BIOS and power saving options on Toshiba portables.
1249
1250 For information on utilities to make use of this driver see the
1251 Toshiba Linux utilities web site at:
1252 <http://www.buzzard.org.uk/toshiba/>.
1253
1254 Say Y if you intend to run this kernel on a Toshiba portable.
1255 Say N otherwise.
1256
1257 config I8K
1258 tristate "Dell i8k legacy laptop support"
1259 select HWMON
1260 select SENSORS_DELL_SMM
1261 ---help---
1262 This option enables legacy /proc/i8k userspace interface in hwmon
1263 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1264 temperature and allows controlling fan speeds of Dell laptops via
1265 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1266 it reports also power and hotkey status. For fan speed control is
1267 needed userspace package i8kutils.
1268
1269 Say Y if you intend to run this kernel on old Dell laptops or want to
1270 use userspace package i8kutils.
1271 Say N otherwise.
1272
1273 config X86_REBOOTFIXUPS
1274 bool "Enable X86 board specific fixups for reboot"
1275 depends on X86_32
1276 ---help---
1277 This enables chipset and/or board specific fixups to be done
1278 in order to get reboot to work correctly. This is only needed on
1279 some combinations of hardware and BIOS. The symptom, for which
1280 this config is intended, is when reboot ends with a stalled/hung
1281 system.
1282
1283 Currently, the only fixup is for the Geode machines using
1284 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1285
1286 Say Y if you want to enable the fixup. Currently, it's safe to
1287 enable this option even if you don't need it.
1288 Say N otherwise.
1289
1290 config MICROCODE
1291 bool "CPU microcode loading support"
1292 default y
1293 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1294 select FW_LOADER
1295 ---help---
1296 If you say Y here, you will be able to update the microcode on
1297 Intel and AMD processors. The Intel support is for the IA32 family,
1298 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1299 AMD support is for families 0x10 and later. You will obviously need
1300 the actual microcode binary data itself which is not shipped with
1301 the Linux kernel.
1302
1303 The preferred method to load microcode from a detached initrd is described
1304 in Documentation/x86/microcode.txt. For that you need to enable
1305 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1306 initrd for microcode blobs.
1307
1308 In addition, you can build the microcode into the kernel. For that you
1309 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1310 config option.
1311
1312 config MICROCODE_INTEL
1313 bool "Intel microcode loading support"
1314 depends on MICROCODE
1315 default MICROCODE
1316 select FW_LOADER
1317 ---help---
1318 This options enables microcode patch loading support for Intel
1319 processors.
1320
1321 For the current Intel microcode data package go to
1322 <https://downloadcenter.intel.com> and search for
1323 'Linux Processor Microcode Data File'.
1324
1325 config MICROCODE_AMD
1326 bool "AMD microcode loading support"
1327 depends on MICROCODE
1328 select FW_LOADER
1329 ---help---
1330 If you select this option, microcode patch loading support for AMD
1331 processors will be enabled.
1332
1333 config MICROCODE_OLD_INTERFACE
1334 def_bool y
1335 depends on MICROCODE
1336
1337 config X86_MSR
1338 tristate "/dev/cpu/*/msr - Model-specific register support"
1339 ---help---
1340 This device gives privileged processes access to the x86
1341 Model-Specific Registers (MSRs). It is a character device with
1342 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1343 MSR accesses are directed to a specific CPU on multi-processor
1344 systems.
1345
1346 config X86_CPUID
1347 tristate "/dev/cpu/*/cpuid - CPU information support"
1348 ---help---
1349 This device gives processes access to the x86 CPUID instruction to
1350 be executed on a specific processor. It is a character device
1351 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1352 /dev/cpu/31/cpuid.
1353
1354 choice
1355 prompt "High Memory Support"
1356 default HIGHMEM4G
1357 depends on X86_32
1358
1359 config NOHIGHMEM
1360 bool "off"
1361 ---help---
1362 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1363 However, the address space of 32-bit x86 processors is only 4
1364 Gigabytes large. That means that, if you have a large amount of
1365 physical memory, not all of it can be "permanently mapped" by the
1366 kernel. The physical memory that's not permanently mapped is called
1367 "high memory".
1368
1369 If you are compiling a kernel which will never run on a machine with
1370 more than 1 Gigabyte total physical RAM, answer "off" here (default
1371 choice and suitable for most users). This will result in a "3GB/1GB"
1372 split: 3GB are mapped so that each process sees a 3GB virtual memory
1373 space and the remaining part of the 4GB virtual memory space is used
1374 by the kernel to permanently map as much physical memory as
1375 possible.
1376
1377 If the machine has between 1 and 4 Gigabytes physical RAM, then
1378 answer "4GB" here.
1379
1380 If more than 4 Gigabytes is used then answer "64GB" here. This
1381 selection turns Intel PAE (Physical Address Extension) mode on.
1382 PAE implements 3-level paging on IA32 processors. PAE is fully
1383 supported by Linux, PAE mode is implemented on all recent Intel
1384 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1385 then the kernel will not boot on CPUs that don't support PAE!
1386
1387 The actual amount of total physical memory will either be
1388 auto detected or can be forced by using a kernel command line option
1389 such as "mem=256M". (Try "man bootparam" or see the documentation of
1390 your boot loader (lilo or loadlin) about how to pass options to the
1391 kernel at boot time.)
1392
1393 If unsure, say "off".
1394
1395 config HIGHMEM4G
1396 bool "4GB"
1397 ---help---
1398 Select this if you have a 32-bit processor and between 1 and 4
1399 gigabytes of physical RAM.
1400
1401 config HIGHMEM64G
1402 bool "64GB"
1403 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1404 select X86_PAE
1405 ---help---
1406 Select this if you have a 32-bit processor and more than 4
1407 gigabytes of physical RAM.
1408
1409 endchoice
1410
1411 choice
1412 prompt "Memory split" if EXPERT
1413 default VMSPLIT_3G
1414 depends on X86_32
1415 ---help---
1416 Select the desired split between kernel and user memory.
1417
1418 If the address range available to the kernel is less than the
1419 physical memory installed, the remaining memory will be available
1420 as "high memory". Accessing high memory is a little more costly
1421 than low memory, as it needs to be mapped into the kernel first.
1422 Note that increasing the kernel address space limits the range
1423 available to user programs, making the address space there
1424 tighter. Selecting anything other than the default 3G/1G split
1425 will also likely make your kernel incompatible with binary-only
1426 kernel modules.
1427
1428 If you are not absolutely sure what you are doing, leave this
1429 option alone!
1430
1431 config VMSPLIT_3G
1432 bool "3G/1G user/kernel split"
1433 config VMSPLIT_3G_OPT
1434 depends on !X86_PAE
1435 bool "3G/1G user/kernel split (for full 1G low memory)"
1436 config VMSPLIT_2G
1437 bool "2G/2G user/kernel split"
1438 config VMSPLIT_2G_OPT
1439 depends on !X86_PAE
1440 bool "2G/2G user/kernel split (for full 2G low memory)"
1441 config VMSPLIT_1G
1442 bool "1G/3G user/kernel split"
1443 endchoice
1444
1445 config PAGE_OFFSET
1446 hex
1447 default 0xB0000000 if VMSPLIT_3G_OPT
1448 default 0x80000000 if VMSPLIT_2G
1449 default 0x78000000 if VMSPLIT_2G_OPT
1450 default 0x40000000 if VMSPLIT_1G
1451 default 0xC0000000
1452 depends on X86_32
1453
1454 config HIGHMEM
1455 def_bool y
1456 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1457
1458 config X86_PAE
1459 bool "PAE (Physical Address Extension) Support"
1460 depends on X86_32 && !HIGHMEM4G
1461 select PHYS_ADDR_T_64BIT
1462 select SWIOTLB
1463 ---help---
1464 PAE is required for NX support, and furthermore enables
1465 larger swapspace support for non-overcommit purposes. It
1466 has the cost of more pagetable lookup overhead, and also
1467 consumes more pagetable space per process.
1468
1469 config X86_5LEVEL
1470 bool "Enable 5-level page tables support"
1471 select DYNAMIC_MEMORY_LAYOUT
1472 select SPARSEMEM_VMEMMAP
1473 depends on X86_64
1474 ---help---
1475 5-level paging enables access to larger address space:
1476 upto 128 PiB of virtual address space and 4 PiB of
1477 physical address space.
1478
1479 It will be supported by future Intel CPUs.
1480
1481 A kernel with the option enabled can be booted on machines that
1482 support 4- or 5-level paging.
1483
1484 See Documentation/x86/x86_64/5level-paging.txt for more
1485 information.
1486
1487 Say N if unsure.
1488
1489 config X86_DIRECT_GBPAGES
1490 def_bool y
1491 depends on X86_64 && !DEBUG_PAGEALLOC
1492 ---help---
1493 Certain kernel features effectively disable kernel
1494 linear 1 GB mappings (even if the CPU otherwise
1495 supports them), so don't confuse the user by printing
1496 that we have them enabled.
1497
1498 config X86_CPA_STATISTICS
1499 bool "Enable statistic for Change Page Attribute"
1500 depends on DEBUG_FS
1501 ---help---
1502 Expose statistics about the Change Page Attribute mechanims, which
1503 helps to determine the effectivness of preserving large and huge
1504 page mappings when mapping protections are changed.
1505
1506 config ARCH_HAS_MEM_ENCRYPT
1507 def_bool y
1508
1509 config AMD_MEM_ENCRYPT
1510 bool "AMD Secure Memory Encryption (SME) support"
1511 depends on X86_64 && CPU_SUP_AMD
1512 select DYNAMIC_PHYSICAL_MASK
1513 ---help---
1514 Say yes to enable support for the encryption of system memory.
1515 This requires an AMD processor that supports Secure Memory
1516 Encryption (SME).
1517
1518 config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1519 bool "Activate AMD Secure Memory Encryption (SME) by default"
1520 default y
1521 depends on AMD_MEM_ENCRYPT
1522 ---help---
1523 Say yes to have system memory encrypted by default if running on
1524 an AMD processor that supports Secure Memory Encryption (SME).
1525
1526 If set to Y, then the encryption of system memory can be
1527 deactivated with the mem_encrypt=off command line option.
1528
1529 If set to N, then the encryption of system memory can be
1530 activated with the mem_encrypt=on command line option.
1531
1532 config ARCH_USE_MEMREMAP_PROT
1533 def_bool y
1534 depends on AMD_MEM_ENCRYPT
1535
1536 # Common NUMA Features
1537 config NUMA
1538 bool "Numa Memory Allocation and Scheduler Support"
1539 depends on SMP
1540 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1541 default y if X86_BIGSMP
1542 ---help---
1543 Enable NUMA (Non Uniform Memory Access) support.
1544
1545 The kernel will try to allocate memory used by a CPU on the
1546 local memory controller of the CPU and add some more
1547 NUMA awareness to the kernel.
1548
1549 For 64-bit this is recommended if the system is Intel Core i7
1550 (or later), AMD Opteron, or EM64T NUMA.
1551
1552 For 32-bit this is only needed if you boot a 32-bit
1553 kernel on a 64-bit NUMA platform.
1554
1555 Otherwise, you should say N.
1556
1557 config AMD_NUMA
1558 def_bool y
1559 prompt "Old style AMD Opteron NUMA detection"
1560 depends on X86_64 && NUMA && PCI
1561 ---help---
1562 Enable AMD NUMA node topology detection. You should say Y here if
1563 you have a multi processor AMD system. This uses an old method to
1564 read the NUMA configuration directly from the builtin Northbridge
1565 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1566 which also takes priority if both are compiled in.
1567
1568 config X86_64_ACPI_NUMA
1569 def_bool y
1570 prompt "ACPI NUMA detection"
1571 depends on X86_64 && NUMA && ACPI && PCI
1572 select ACPI_NUMA
1573 ---help---
1574 Enable ACPI SRAT based node topology detection.
1575
1576 # Some NUMA nodes have memory ranges that span
1577 # other nodes. Even though a pfn is valid and
1578 # between a node's start and end pfns, it may not
1579 # reside on that node. See memmap_init_zone()
1580 # for details.
1581 config NODES_SPAN_OTHER_NODES
1582 def_bool y
1583 depends on X86_64_ACPI_NUMA
1584
1585 config NUMA_EMU
1586 bool "NUMA emulation"
1587 depends on NUMA
1588 ---help---
1589 Enable NUMA emulation. A flat machine will be split
1590 into virtual nodes when booted with "numa=fake=N", where N is the
1591 number of nodes. This is only useful for debugging.
1592
1593 config NODES_SHIFT
1594 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1595 range 1 10
1596 default "10" if MAXSMP
1597 default "6" if X86_64
1598 default "3"
1599 depends on NEED_MULTIPLE_NODES
1600 ---help---
1601 Specify the maximum number of NUMA Nodes available on the target
1602 system. Increases memory reserved to accommodate various tables.
1603
1604 config ARCH_HAVE_MEMORY_PRESENT
1605 def_bool y
1606 depends on X86_32 && DISCONTIGMEM
1607
1608 config ARCH_FLATMEM_ENABLE
1609 def_bool y
1610 depends on X86_32 && !NUMA
1611
1612 config ARCH_DISCONTIGMEM_ENABLE
1613 def_bool y
1614 depends on NUMA && X86_32
1615
1616 config ARCH_DISCONTIGMEM_DEFAULT
1617 def_bool y
1618 depends on NUMA && X86_32
1619
1620 config ARCH_SPARSEMEM_ENABLE
1621 def_bool y
1622 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1623 select SPARSEMEM_STATIC if X86_32
1624 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1625
1626 config ARCH_SPARSEMEM_DEFAULT
1627 def_bool y
1628 depends on X86_64
1629
1630 config ARCH_SELECT_MEMORY_MODEL
1631 def_bool y
1632 depends on ARCH_SPARSEMEM_ENABLE
1633
1634 config ARCH_MEMORY_PROBE
1635 bool "Enable sysfs memory/probe interface"
1636 depends on X86_64 && MEMORY_HOTPLUG
1637 help
1638 This option enables a sysfs memory/probe interface for testing.
1639 See Documentation/memory-hotplug.txt for more information.
1640 If you are unsure how to answer this question, answer N.
1641
1642 config ARCH_PROC_KCORE_TEXT
1643 def_bool y
1644 depends on X86_64 && PROC_KCORE
1645
1646 config ILLEGAL_POINTER_VALUE
1647 hex
1648 default 0 if X86_32
1649 default 0xdead000000000000 if X86_64
1650
1651 config X86_PMEM_LEGACY_DEVICE
1652 bool
1653
1654 config X86_PMEM_LEGACY
1655 tristate "Support non-standard NVDIMMs and ADR protected memory"
1656 depends on PHYS_ADDR_T_64BIT
1657 depends on BLK_DEV
1658 select X86_PMEM_LEGACY_DEVICE
1659 select LIBNVDIMM
1660 help
1661 Treat memory marked using the non-standard e820 type of 12 as used
1662 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1663 The kernel will offer these regions to the 'pmem' driver so
1664 they can be used for persistent storage.
1665
1666 Say Y if unsure.
1667
1668 config HIGHPTE
1669 bool "Allocate 3rd-level pagetables from highmem"
1670 depends on HIGHMEM
1671 ---help---
1672 The VM uses one page table entry for each page of physical memory.
1673 For systems with a lot of RAM, this can be wasteful of precious
1674 low memory. Setting this option will put user-space page table
1675 entries in high memory.
1676
1677 config X86_CHECK_BIOS_CORRUPTION
1678 bool "Check for low memory corruption"
1679 ---help---
1680 Periodically check for memory corruption in low memory, which
1681 is suspected to be caused by BIOS. Even when enabled in the
1682 configuration, it is disabled at runtime. Enable it by
1683 setting "memory_corruption_check=1" on the kernel command
1684 line. By default it scans the low 64k of memory every 60
1685 seconds; see the memory_corruption_check_size and
1686 memory_corruption_check_period parameters in
1687 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1688
1689 When enabled with the default parameters, this option has
1690 almost no overhead, as it reserves a relatively small amount
1691 of memory and scans it infrequently. It both detects corruption
1692 and prevents it from affecting the running system.
1693
1694 It is, however, intended as a diagnostic tool; if repeatable
1695 BIOS-originated corruption always affects the same memory,
1696 you can use memmap= to prevent the kernel from using that
1697 memory.
1698
1699 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1700 bool "Set the default setting of memory_corruption_check"
1701 depends on X86_CHECK_BIOS_CORRUPTION
1702 default y
1703 ---help---
1704 Set whether the default state of memory_corruption_check is
1705 on or off.
1706
1707 config X86_RESERVE_LOW
1708 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1709 default 64
1710 range 4 640
1711 ---help---
1712 Specify the amount of low memory to reserve for the BIOS.
1713
1714 The first page contains BIOS data structures that the kernel
1715 must not use, so that page must always be reserved.
1716
1717 By default we reserve the first 64K of physical RAM, as a
1718 number of BIOSes are known to corrupt that memory range
1719 during events such as suspend/resume or monitor cable
1720 insertion, so it must not be used by the kernel.
1721
1722 You can set this to 4 if you are absolutely sure that you
1723 trust the BIOS to get all its memory reservations and usages
1724 right. If you know your BIOS have problems beyond the
1725 default 64K area, you can set this to 640 to avoid using the
1726 entire low memory range.
1727
1728 If you have doubts about the BIOS (e.g. suspend/resume does
1729 not work or there's kernel crashes after certain hardware
1730 hotplug events) then you might want to enable
1731 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1732 typical corruption patterns.
1733
1734 Leave this to the default value of 64 if you are unsure.
1735
1736 config MATH_EMULATION
1737 bool
1738 depends on MODIFY_LDT_SYSCALL
1739 prompt "Math emulation" if X86_32
1740 ---help---
1741 Linux can emulate a math coprocessor (used for floating point
1742 operations) if you don't have one. 486DX and Pentium processors have
1743 a math coprocessor built in, 486SX and 386 do not, unless you added
1744 a 487DX or 387, respectively. (The messages during boot time can
1745 give you some hints here ["man dmesg"].) Everyone needs either a
1746 coprocessor or this emulation.
1747
1748 If you don't have a math coprocessor, you need to say Y here; if you
1749 say Y here even though you have a coprocessor, the coprocessor will
1750 be used nevertheless. (This behavior can be changed with the kernel
1751 command line option "no387", which comes handy if your coprocessor
1752 is broken. Try "man bootparam" or see the documentation of your boot
1753 loader (lilo or loadlin) about how to pass options to the kernel at
1754 boot time.) This means that it is a good idea to say Y here if you
1755 intend to use this kernel on different machines.
1756
1757 More information about the internals of the Linux math coprocessor
1758 emulation can be found in <file:arch/x86/math-emu/README>.
1759
1760 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1761 kernel, it won't hurt.
1762
1763 config MTRR
1764 def_bool y
1765 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1766 ---help---
1767 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1768 the Memory Type Range Registers (MTRRs) may be used to control
1769 processor access to memory ranges. This is most useful if you have
1770 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1771 allows bus write transfers to be combined into a larger transfer
1772 before bursting over the PCI/AGP bus. This can increase performance
1773 of image write operations 2.5 times or more. Saying Y here creates a
1774 /proc/mtrr file which may be used to manipulate your processor's
1775 MTRRs. Typically the X server should use this.
1776
1777 This code has a reasonably generic interface so that similar
1778 control registers on other processors can be easily supported
1779 as well:
1780
1781 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1782 Registers (ARRs) which provide a similar functionality to MTRRs. For
1783 these, the ARRs are used to emulate the MTRRs.
1784 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1785 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1786 write-combining. All of these processors are supported by this code
1787 and it makes sense to say Y here if you have one of them.
1788
1789 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1790 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1791 can lead to all sorts of problems, so it's good to say Y here.
1792
1793 You can safely say Y even if your machine doesn't have MTRRs, you'll
1794 just add about 9 KB to your kernel.
1795
1796 See <file:Documentation/x86/mtrr.txt> for more information.
1797
1798 config MTRR_SANITIZER
1799 def_bool y
1800 prompt "MTRR cleanup support"
1801 depends on MTRR
1802 ---help---
1803 Convert MTRR layout from continuous to discrete, so X drivers can
1804 add writeback entries.
1805
1806 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1807 The largest mtrr entry size for a continuous block can be set with
1808 mtrr_chunk_size.
1809
1810 If unsure, say Y.
1811
1812 config MTRR_SANITIZER_ENABLE_DEFAULT
1813 int "MTRR cleanup enable value (0-1)"
1814 range 0 1
1815 default "0"
1816 depends on MTRR_SANITIZER
1817 ---help---
1818 Enable mtrr cleanup default value
1819
1820 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1821 int "MTRR cleanup spare reg num (0-7)"
1822 range 0 7
1823 default "1"
1824 depends on MTRR_SANITIZER
1825 ---help---
1826 mtrr cleanup spare entries default, it can be changed via
1827 mtrr_spare_reg_nr=N on the kernel command line.
1828
1829 config X86_PAT
1830 def_bool y
1831 prompt "x86 PAT support" if EXPERT
1832 depends on MTRR
1833 ---help---
1834 Use PAT attributes to setup page level cache control.
1835
1836 PATs are the modern equivalents of MTRRs and are much more
1837 flexible than MTRRs.
1838
1839 Say N here if you see bootup problems (boot crash, boot hang,
1840 spontaneous reboots) or a non-working video driver.
1841
1842 If unsure, say Y.
1843
1844 config ARCH_USES_PG_UNCACHED
1845 def_bool y
1846 depends on X86_PAT
1847
1848 config ARCH_RANDOM
1849 def_bool y
1850 prompt "x86 architectural random number generator" if EXPERT
1851 ---help---
1852 Enable the x86 architectural RDRAND instruction
1853 (Intel Bull Mountain technology) to generate random numbers.
1854 If supported, this is a high bandwidth, cryptographically
1855 secure hardware random number generator.
1856
1857 config X86_SMAP
1858 def_bool y
1859 prompt "Supervisor Mode Access Prevention" if EXPERT
1860 ---help---
1861 Supervisor Mode Access Prevention (SMAP) is a security
1862 feature in newer Intel processors. There is a small
1863 performance cost if this enabled and turned on; there is
1864 also a small increase in the kernel size if this is enabled.
1865
1866 If unsure, say Y.
1867
1868 config X86_INTEL_UMIP
1869 def_bool y
1870 depends on CPU_SUP_INTEL
1871 prompt "Intel User Mode Instruction Prevention" if EXPERT
1872 ---help---
1873 The User Mode Instruction Prevention (UMIP) is a security
1874 feature in newer Intel processors. If enabled, a general
1875 protection fault is issued if the SGDT, SLDT, SIDT, SMSW
1876 or STR instructions are executed in user mode. These instructions
1877 unnecessarily expose information about the hardware state.
1878
1879 The vast majority of applications do not use these instructions.
1880 For the very few that do, software emulation is provided in
1881 specific cases in protected and virtual-8086 modes. Emulated
1882 results are dummy.
1883
1884 config X86_INTEL_MPX
1885 prompt "Intel MPX (Memory Protection Extensions)"
1886 def_bool n
1887 # Note: only available in 64-bit mode due to VMA flags shortage
1888 depends on CPU_SUP_INTEL && X86_64
1889 select ARCH_USES_HIGH_VMA_FLAGS
1890 ---help---
1891 MPX provides hardware features that can be used in
1892 conjunction with compiler-instrumented code to check
1893 memory references. It is designed to detect buffer
1894 overflow or underflow bugs.
1895
1896 This option enables running applications which are
1897 instrumented or otherwise use MPX. It does not use MPX
1898 itself inside the kernel or to protect the kernel
1899 against bad memory references.
1900
1901 Enabling this option will make the kernel larger:
1902 ~8k of kernel text and 36 bytes of data on a 64-bit
1903 defconfig. It adds a long to the 'mm_struct' which
1904 will increase the kernel memory overhead of each
1905 process and adds some branches to paths used during
1906 exec() and munmap().
1907
1908 For details, see Documentation/x86/intel_mpx.txt
1909
1910 If unsure, say N.
1911
1912 config X86_INTEL_MEMORY_PROTECTION_KEYS
1913 prompt "Intel Memory Protection Keys"
1914 def_bool y
1915 # Note: only available in 64-bit mode
1916 depends on CPU_SUP_INTEL && X86_64
1917 select ARCH_USES_HIGH_VMA_FLAGS
1918 select ARCH_HAS_PKEYS
1919 ---help---
1920 Memory Protection Keys provides a mechanism for enforcing
1921 page-based protections, but without requiring modification of the
1922 page tables when an application changes protection domains.
1923
1924 For details, see Documentation/x86/protection-keys.txt
1925
1926 If unsure, say y.
1927
1928 config EFI
1929 bool "EFI runtime service support"
1930 depends on ACPI
1931 select UCS2_STRING
1932 select EFI_RUNTIME_WRAPPERS
1933 ---help---
1934 This enables the kernel to use EFI runtime services that are
1935 available (such as the EFI variable services).
1936
1937 This option is only useful on systems that have EFI firmware.
1938 In addition, you should use the latest ELILO loader available
1939 at <http://elilo.sourceforge.net> in order to take advantage
1940 of EFI runtime services. However, even with this option, the
1941 resultant kernel should continue to boot on existing non-EFI
1942 platforms.
1943
1944 config EFI_STUB
1945 bool "EFI stub support"
1946 depends on EFI && !X86_USE_3DNOW
1947 select RELOCATABLE
1948 ---help---
1949 This kernel feature allows a bzImage to be loaded directly
1950 by EFI firmware without the use of a bootloader.
1951
1952 See Documentation/efi-stub.txt for more information.
1953
1954 config EFI_MIXED
1955 bool "EFI mixed-mode support"
1956 depends on EFI_STUB && X86_64
1957 ---help---
1958 Enabling this feature allows a 64-bit kernel to be booted
1959 on a 32-bit firmware, provided that your CPU supports 64-bit
1960 mode.
1961
1962 Note that it is not possible to boot a mixed-mode enabled
1963 kernel via the EFI boot stub - a bootloader that supports
1964 the EFI handover protocol must be used.
1965
1966 If unsure, say N.
1967
1968 config SECCOMP
1969 def_bool y
1970 prompt "Enable seccomp to safely compute untrusted bytecode"
1971 ---help---
1972 This kernel feature is useful for number crunching applications
1973 that may need to compute untrusted bytecode during their
1974 execution. By using pipes or other transports made available to
1975 the process as file descriptors supporting the read/write
1976 syscalls, it's possible to isolate those applications in
1977 their own address space using seccomp. Once seccomp is
1978 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1979 and the task is only allowed to execute a few safe syscalls
1980 defined by each seccomp mode.
1981
1982 If unsure, say Y. Only embedded should say N here.
1983
1984 source "kernel/Kconfig.hz"
1985
1986 config KEXEC
1987 bool "kexec system call"
1988 select KEXEC_CORE
1989 ---help---
1990 kexec is a system call that implements the ability to shutdown your
1991 current kernel, and to start another kernel. It is like a reboot
1992 but it is independent of the system firmware. And like a reboot
1993 you can start any kernel with it, not just Linux.
1994
1995 The name comes from the similarity to the exec system call.
1996
1997 It is an ongoing process to be certain the hardware in a machine
1998 is properly shutdown, so do not be surprised if this code does not
1999 initially work for you. As of this writing the exact hardware
2000 interface is strongly in flux, so no good recommendation can be
2001 made.
2002
2003 config KEXEC_FILE
2004 bool "kexec file based system call"
2005 select KEXEC_CORE
2006 select BUILD_BIN2C
2007 depends on X86_64
2008 depends on CRYPTO=y
2009 depends on CRYPTO_SHA256=y
2010 ---help---
2011 This is new version of kexec system call. This system call is
2012 file based and takes file descriptors as system call argument
2013 for kernel and initramfs as opposed to list of segments as
2014 accepted by previous system call.
2015
2016 config ARCH_HAS_KEXEC_PURGATORY
2017 def_bool KEXEC_FILE
2018
2019 config KEXEC_VERIFY_SIG
2020 bool "Verify kernel signature during kexec_file_load() syscall"
2021 depends on KEXEC_FILE
2022 ---help---
2023 This option makes kernel signature verification mandatory for
2024 the kexec_file_load() syscall.
2025
2026 In addition to that option, you need to enable signature
2027 verification for the corresponding kernel image type being
2028 loaded in order for this to work.
2029
2030 config KEXEC_BZIMAGE_VERIFY_SIG
2031 bool "Enable bzImage signature verification support"
2032 depends on KEXEC_VERIFY_SIG
2033 depends on SIGNED_PE_FILE_VERIFICATION
2034 select SYSTEM_TRUSTED_KEYRING
2035 ---help---
2036 Enable bzImage signature verification support.
2037
2038 config CRASH_DUMP
2039 bool "kernel crash dumps"
2040 depends on X86_64 || (X86_32 && HIGHMEM)
2041 ---help---
2042 Generate crash dump after being started by kexec.
2043 This should be normally only set in special crash dump kernels
2044 which are loaded in the main kernel with kexec-tools into
2045 a specially reserved region and then later executed after
2046 a crash by kdump/kexec. The crash dump kernel must be compiled
2047 to a memory address not used by the main kernel or BIOS using
2048 PHYSICAL_START, or it must be built as a relocatable image
2049 (CONFIG_RELOCATABLE=y).
2050 For more details see Documentation/kdump/kdump.txt
2051
2052 config KEXEC_JUMP
2053 bool "kexec jump"
2054 depends on KEXEC && HIBERNATION
2055 ---help---
2056 Jump between original kernel and kexeced kernel and invoke
2057 code in physical address mode via KEXEC
2058
2059 config PHYSICAL_START
2060 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2061 default "0x1000000"
2062 ---help---
2063 This gives the physical address where the kernel is loaded.
2064
2065 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2066 bzImage will decompress itself to above physical address and
2067 run from there. Otherwise, bzImage will run from the address where
2068 it has been loaded by the boot loader and will ignore above physical
2069 address.
2070
2071 In normal kdump cases one does not have to set/change this option
2072 as now bzImage can be compiled as a completely relocatable image
2073 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2074 address. This option is mainly useful for the folks who don't want
2075 to use a bzImage for capturing the crash dump and want to use a
2076 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2077 to be specifically compiled to run from a specific memory area
2078 (normally a reserved region) and this option comes handy.
2079
2080 So if you are using bzImage for capturing the crash dump,
2081 leave the value here unchanged to 0x1000000 and set
2082 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2083 for capturing the crash dump change this value to start of
2084 the reserved region. In other words, it can be set based on
2085 the "X" value as specified in the "crashkernel=YM@XM"
2086 command line boot parameter passed to the panic-ed
2087 kernel. Please take a look at Documentation/kdump/kdump.txt
2088 for more details about crash dumps.
2089
2090 Usage of bzImage for capturing the crash dump is recommended as
2091 one does not have to build two kernels. Same kernel can be used
2092 as production kernel and capture kernel. Above option should have
2093 gone away after relocatable bzImage support is introduced. But it
2094 is present because there are users out there who continue to use
2095 vmlinux for dump capture. This option should go away down the
2096 line.
2097
2098 Don't change this unless you know what you are doing.
2099
2100 config RELOCATABLE
2101 bool "Build a relocatable kernel"
2102 default y
2103 ---help---
2104 This builds a kernel image that retains relocation information
2105 so it can be loaded someplace besides the default 1MB.
2106 The relocations tend to make the kernel binary about 10% larger,
2107 but are discarded at runtime.
2108
2109 One use is for the kexec on panic case where the recovery kernel
2110 must live at a different physical address than the primary
2111 kernel.
2112
2113 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2114 it has been loaded at and the compile time physical address
2115 (CONFIG_PHYSICAL_START) is used as the minimum location.
2116
2117 config RANDOMIZE_BASE
2118 bool "Randomize the address of the kernel image (KASLR)"
2119 depends on RELOCATABLE
2120 default y
2121 ---help---
2122 In support of Kernel Address Space Layout Randomization (KASLR),
2123 this randomizes the physical address at which the kernel image
2124 is decompressed and the virtual address where the kernel
2125 image is mapped, as a security feature that deters exploit
2126 attempts relying on knowledge of the location of kernel
2127 code internals.
2128
2129 On 64-bit, the kernel physical and virtual addresses are
2130 randomized separately. The physical address will be anywhere
2131 between 16MB and the top of physical memory (up to 64TB). The
2132 virtual address will be randomized from 16MB up to 1GB (9 bits
2133 of entropy). Note that this also reduces the memory space
2134 available to kernel modules from 1.5GB to 1GB.
2135
2136 On 32-bit, the kernel physical and virtual addresses are
2137 randomized together. They will be randomized from 16MB up to
2138 512MB (8 bits of entropy).
2139
2140 Entropy is generated using the RDRAND instruction if it is
2141 supported. If RDTSC is supported, its value is mixed into
2142 the entropy pool as well. If neither RDRAND nor RDTSC are
2143 supported, then entropy is read from the i8254 timer. The
2144 usable entropy is limited by the kernel being built using
2145 2GB addressing, and that PHYSICAL_ALIGN must be at a
2146 minimum of 2MB. As a result, only 10 bits of entropy are
2147 theoretically possible, but the implementations are further
2148 limited due to memory layouts.
2149
2150 If unsure, say Y.
2151
2152 # Relocation on x86 needs some additional build support
2153 config X86_NEED_RELOCS
2154 def_bool y
2155 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2156
2157 config PHYSICAL_ALIGN
2158 hex "Alignment value to which kernel should be aligned"
2159 default "0x200000"
2160 range 0x2000 0x1000000 if X86_32
2161 range 0x200000 0x1000000 if X86_64
2162 ---help---
2163 This value puts the alignment restrictions on physical address
2164 where kernel is loaded and run from. Kernel is compiled for an
2165 address which meets above alignment restriction.
2166
2167 If bootloader loads the kernel at a non-aligned address and
2168 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2169 address aligned to above value and run from there.
2170
2171 If bootloader loads the kernel at a non-aligned address and
2172 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2173 load address and decompress itself to the address it has been
2174 compiled for and run from there. The address for which kernel is
2175 compiled already meets above alignment restrictions. Hence the
2176 end result is that kernel runs from a physical address meeting
2177 above alignment restrictions.
2178
2179 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2180 this value must be a multiple of 0x200000.
2181
2182 Don't change this unless you know what you are doing.
2183
2184 config DYNAMIC_MEMORY_LAYOUT
2185 bool
2186 ---help---
2187 This option makes base addresses of vmalloc and vmemmap as well as
2188 __PAGE_OFFSET movable during boot.
2189
2190 config RANDOMIZE_MEMORY
2191 bool "Randomize the kernel memory sections"
2192 depends on X86_64
2193 depends on RANDOMIZE_BASE
2194 select DYNAMIC_MEMORY_LAYOUT
2195 default RANDOMIZE_BASE
2196 ---help---
2197 Randomizes the base virtual address of kernel memory sections
2198 (physical memory mapping, vmalloc & vmemmap). This security feature
2199 makes exploits relying on predictable memory locations less reliable.
2200
2201 The order of allocations remains unchanged. Entropy is generated in
2202 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2203 configuration have in average 30,000 different possible virtual
2204 addresses for each memory section.
2205
2206 If unsure, say Y.
2207
2208 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2209 hex "Physical memory mapping padding" if EXPERT
2210 depends on RANDOMIZE_MEMORY
2211 default "0xa" if MEMORY_HOTPLUG
2212 default "0x0"
2213 range 0x1 0x40 if MEMORY_HOTPLUG
2214 range 0x0 0x40
2215 ---help---
2216 Define the padding in terabytes added to the existing physical
2217 memory size during kernel memory randomization. It is useful
2218 for memory hotplug support but reduces the entropy available for
2219 address randomization.
2220
2221 If unsure, leave at the default value.
2222
2223 config HOTPLUG_CPU
2224 bool "Support for hot-pluggable CPUs"
2225 depends on SMP
2226 ---help---
2227 Say Y here to allow turning CPUs off and on. CPUs can be
2228 controlled through /sys/devices/system/cpu.
2229 ( Note: power management support will enable this option
2230 automatically on SMP systems. )
2231 Say N if you want to disable CPU hotplug.
2232
2233 config BOOTPARAM_HOTPLUG_CPU0
2234 bool "Set default setting of cpu0_hotpluggable"
2235 depends on HOTPLUG_CPU
2236 ---help---
2237 Set whether default state of cpu0_hotpluggable is on or off.
2238
2239 Say Y here to enable CPU0 hotplug by default. If this switch
2240 is turned on, there is no need to give cpu0_hotplug kernel
2241 parameter and the CPU0 hotplug feature is enabled by default.
2242
2243 Please note: there are two known CPU0 dependencies if you want
2244 to enable the CPU0 hotplug feature either by this switch or by
2245 cpu0_hotplug kernel parameter.
2246
2247 First, resume from hibernate or suspend always starts from CPU0.
2248 So hibernate and suspend are prevented if CPU0 is offline.
2249
2250 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2251 offline if any interrupt can not migrate out of CPU0. There may
2252 be other CPU0 dependencies.
2253
2254 Please make sure the dependencies are under your control before
2255 you enable this feature.
2256
2257 Say N if you don't want to enable CPU0 hotplug feature by default.
2258 You still can enable the CPU0 hotplug feature at boot by kernel
2259 parameter cpu0_hotplug.
2260
2261 config DEBUG_HOTPLUG_CPU0
2262 def_bool n
2263 prompt "Debug CPU0 hotplug"
2264 depends on HOTPLUG_CPU
2265 ---help---
2266 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2267 soon as possible and boots up userspace with CPU0 offlined. User
2268 can online CPU0 back after boot time.
2269
2270 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2271 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2272 compilation or giving cpu0_hotplug kernel parameter at boot.
2273
2274 If unsure, say N.
2275
2276 config COMPAT_VDSO
2277 def_bool n
2278 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2279 depends on COMPAT_32
2280 ---help---
2281 Certain buggy versions of glibc will crash if they are
2282 presented with a 32-bit vDSO that is not mapped at the address
2283 indicated in its segment table.
2284
2285 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2286 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2287 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2288 the only released version with the bug, but OpenSUSE 9
2289 contains a buggy "glibc 2.3.2".
2290
2291 The symptom of the bug is that everything crashes on startup, saying:
2292 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2293
2294 Saying Y here changes the default value of the vdso32 boot
2295 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2296 This works around the glibc bug but hurts performance.
2297
2298 If unsure, say N: if you are compiling your own kernel, you
2299 are unlikely to be using a buggy version of glibc.
2300
2301 choice
2302 prompt "vsyscall table for legacy applications"
2303 depends on X86_64
2304 default LEGACY_VSYSCALL_EMULATE
2305 help
2306 Legacy user code that does not know how to find the vDSO expects
2307 to be able to issue three syscalls by calling fixed addresses in
2308 kernel space. Since this location is not randomized with ASLR,
2309 it can be used to assist security vulnerability exploitation.
2310
2311 This setting can be changed at boot time via the kernel command
2312 line parameter vsyscall=[emulate|none].
2313
2314 On a system with recent enough glibc (2.14 or newer) and no
2315 static binaries, you can say None without a performance penalty
2316 to improve security.
2317
2318 If unsure, select "Emulate".
2319
2320 config LEGACY_VSYSCALL_EMULATE
2321 bool "Emulate"
2322 help
2323 The kernel traps and emulates calls into the fixed
2324 vsyscall address mapping. This makes the mapping
2325 non-executable, but it still contains known contents,
2326 which could be used in certain rare security vulnerability
2327 exploits. This configuration is recommended when userspace
2328 still uses the vsyscall area.
2329
2330 config LEGACY_VSYSCALL_NONE
2331 bool "None"
2332 help
2333 There will be no vsyscall mapping at all. This will
2334 eliminate any risk of ASLR bypass due to the vsyscall
2335 fixed address mapping. Attempts to use the vsyscalls
2336 will be reported to dmesg, so that either old or
2337 malicious userspace programs can be identified.
2338
2339 endchoice
2340
2341 config CMDLINE_BOOL
2342 bool "Built-in kernel command line"
2343 ---help---
2344 Allow for specifying boot arguments to the kernel at
2345 build time. On some systems (e.g. embedded ones), it is
2346 necessary or convenient to provide some or all of the
2347 kernel boot arguments with the kernel itself (that is,
2348 to not rely on the boot loader to provide them.)
2349
2350 To compile command line arguments into the kernel,
2351 set this option to 'Y', then fill in the
2352 boot arguments in CONFIG_CMDLINE.
2353
2354 Systems with fully functional boot loaders (i.e. non-embedded)
2355 should leave this option set to 'N'.
2356
2357 config CMDLINE
2358 string "Built-in kernel command string"
2359 depends on CMDLINE_BOOL
2360 default ""
2361 ---help---
2362 Enter arguments here that should be compiled into the kernel
2363 image and used at boot time. If the boot loader provides a
2364 command line at boot time, it is appended to this string to
2365 form the full kernel command line, when the system boots.
2366
2367 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2368 change this behavior.
2369
2370 In most cases, the command line (whether built-in or provided
2371 by the boot loader) should specify the device for the root
2372 file system.
2373
2374 config CMDLINE_OVERRIDE
2375 bool "Built-in command line overrides boot loader arguments"
2376 depends on CMDLINE_BOOL
2377 ---help---
2378 Set this option to 'Y' to have the kernel ignore the boot loader
2379 command line, and use ONLY the built-in command line.
2380
2381 This is used to work around broken boot loaders. This should
2382 be set to 'N' under normal conditions.
2383
2384 config MODIFY_LDT_SYSCALL
2385 bool "Enable the LDT (local descriptor table)" if EXPERT
2386 default y
2387 ---help---
2388 Linux can allow user programs to install a per-process x86
2389 Local Descriptor Table (LDT) using the modify_ldt(2) system
2390 call. This is required to run 16-bit or segmented code such as
2391 DOSEMU or some Wine programs. It is also used by some very old
2392 threading libraries.
2393
2394 Enabling this feature adds a small amount of overhead to
2395 context switches and increases the low-level kernel attack
2396 surface. Disabling it removes the modify_ldt(2) system call.
2397
2398 Saying 'N' here may make sense for embedded or server kernels.
2399
2400 source "kernel/livepatch/Kconfig"
2401
2402 endmenu
2403
2404 config ARCH_HAS_ADD_PAGES
2405 def_bool y
2406 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2407
2408 config ARCH_ENABLE_MEMORY_HOTPLUG
2409 def_bool y
2410 depends on X86_64 || (X86_32 && HIGHMEM)
2411
2412 config ARCH_ENABLE_MEMORY_HOTREMOVE
2413 def_bool y
2414 depends on MEMORY_HOTPLUG
2415
2416 config USE_PERCPU_NUMA_NODE_ID
2417 def_bool y
2418 depends on NUMA
2419
2420 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2421 def_bool y
2422 depends on X86_64 || X86_PAE
2423
2424 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2425 def_bool y
2426 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2427
2428 config ARCH_ENABLE_THP_MIGRATION
2429 def_bool y
2430 depends on X86_64 && TRANSPARENT_HUGEPAGE
2431
2432 menu "Power management and ACPI options"
2433
2434 config ARCH_HIBERNATION_HEADER
2435 def_bool y
2436 depends on HIBERNATION
2437
2438 source "kernel/power/Kconfig"
2439
2440 source "drivers/acpi/Kconfig"
2441
2442 source "drivers/sfi/Kconfig"
2443
2444 config X86_APM_BOOT
2445 def_bool y
2446 depends on APM
2447
2448 menuconfig APM
2449 tristate "APM (Advanced Power Management) BIOS support"
2450 depends on X86_32 && PM_SLEEP
2451 ---help---
2452 APM is a BIOS specification for saving power using several different
2453 techniques. This is mostly useful for battery powered laptops with
2454 APM compliant BIOSes. If you say Y here, the system time will be
2455 reset after a RESUME operation, the /proc/apm device will provide
2456 battery status information, and user-space programs will receive
2457 notification of APM "events" (e.g. battery status change).
2458
2459 If you select "Y" here, you can disable actual use of the APM
2460 BIOS by passing the "apm=off" option to the kernel at boot time.
2461
2462 Note that the APM support is almost completely disabled for
2463 machines with more than one CPU.
2464
2465 In order to use APM, you will need supporting software. For location
2466 and more information, read <file:Documentation/power/apm-acpi.txt>
2467 and the Battery Powered Linux mini-HOWTO, available from
2468 <http://www.tldp.org/docs.html#howto>.
2469
2470 This driver does not spin down disk drives (see the hdparm(8)
2471 manpage ("man 8 hdparm") for that), and it doesn't turn off
2472 VESA-compliant "green" monitors.
2473
2474 This driver does not support the TI 4000M TravelMate and the ACER
2475 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2476 desktop machines also don't have compliant BIOSes, and this driver
2477 may cause those machines to panic during the boot phase.
2478
2479 Generally, if you don't have a battery in your machine, there isn't
2480 much point in using this driver and you should say N. If you get
2481 random kernel OOPSes or reboots that don't seem to be related to
2482 anything, try disabling/enabling this option (or disabling/enabling
2483 APM in your BIOS).
2484
2485 Some other things you should try when experiencing seemingly random,
2486 "weird" problems:
2487
2488 1) make sure that you have enough swap space and that it is
2489 enabled.
2490 2) pass the "no-hlt" option to the kernel
2491 3) switch on floating point emulation in the kernel and pass
2492 the "no387" option to the kernel
2493 4) pass the "floppy=nodma" option to the kernel
2494 5) pass the "mem=4M" option to the kernel (thereby disabling
2495 all but the first 4 MB of RAM)
2496 6) make sure that the CPU is not over clocked.
2497 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2498 8) disable the cache from your BIOS settings
2499 9) install a fan for the video card or exchange video RAM
2500 10) install a better fan for the CPU
2501 11) exchange RAM chips
2502 12) exchange the motherboard.
2503
2504 To compile this driver as a module, choose M here: the
2505 module will be called apm.
2506
2507 if APM
2508
2509 config APM_IGNORE_USER_SUSPEND
2510 bool "Ignore USER SUSPEND"
2511 ---help---
2512 This option will ignore USER SUSPEND requests. On machines with a
2513 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2514 series notebooks, it is necessary to say Y because of a BIOS bug.
2515
2516 config APM_DO_ENABLE
2517 bool "Enable PM at boot time"
2518 ---help---
2519 Enable APM features at boot time. From page 36 of the APM BIOS
2520 specification: "When disabled, the APM BIOS does not automatically
2521 power manage devices, enter the Standby State, enter the Suspend
2522 State, or take power saving steps in response to CPU Idle calls."
2523 This driver will make CPU Idle calls when Linux is idle (unless this
2524 feature is turned off -- see "Do CPU IDLE calls", below). This
2525 should always save battery power, but more complicated APM features
2526 will be dependent on your BIOS implementation. You may need to turn
2527 this option off if your computer hangs at boot time when using APM
2528 support, or if it beeps continuously instead of suspending. Turn
2529 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2530 T400CDT. This is off by default since most machines do fine without
2531 this feature.
2532
2533 config APM_CPU_IDLE
2534 depends on CPU_IDLE
2535 bool "Make CPU Idle calls when idle"
2536 ---help---
2537 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2538 On some machines, this can activate improved power savings, such as
2539 a slowed CPU clock rate, when the machine is idle. These idle calls
2540 are made after the idle loop has run for some length of time (e.g.,
2541 333 mS). On some machines, this will cause a hang at boot time or
2542 whenever the CPU becomes idle. (On machines with more than one CPU,
2543 this option does nothing.)
2544
2545 config APM_DISPLAY_BLANK
2546 bool "Enable console blanking using APM"
2547 ---help---
2548 Enable console blanking using the APM. Some laptops can use this to
2549 turn off the LCD backlight when the screen blanker of the Linux
2550 virtual console blanks the screen. Note that this is only used by
2551 the virtual console screen blanker, and won't turn off the backlight
2552 when using the X Window system. This also doesn't have anything to
2553 do with your VESA-compliant power-saving monitor. Further, this
2554 option doesn't work for all laptops -- it might not turn off your
2555 backlight at all, or it might print a lot of errors to the console,
2556 especially if you are using gpm.
2557
2558 config APM_ALLOW_INTS
2559 bool "Allow interrupts during APM BIOS calls"
2560 ---help---
2561 Normally we disable external interrupts while we are making calls to
2562 the APM BIOS as a measure to lessen the effects of a badly behaving
2563 BIOS implementation. The BIOS should reenable interrupts if it
2564 needs to. Unfortunately, some BIOSes do not -- especially those in
2565 many of the newer IBM Thinkpads. If you experience hangs when you
2566 suspend, try setting this to Y. Otherwise, say N.
2567
2568 endif # APM
2569
2570 source "drivers/cpufreq/Kconfig"
2571
2572 source "drivers/cpuidle/Kconfig"
2573
2574 source "drivers/idle/Kconfig"
2575
2576 endmenu
2577
2578
2579 menu "Bus options (PCI etc.)"
2580
2581 choice
2582 prompt "PCI access mode"
2583 depends on X86_32 && PCI
2584 default PCI_GOANY
2585 ---help---
2586 On PCI systems, the BIOS can be used to detect the PCI devices and
2587 determine their configuration. However, some old PCI motherboards
2588 have BIOS bugs and may crash if this is done. Also, some embedded
2589 PCI-based systems don't have any BIOS at all. Linux can also try to
2590 detect the PCI hardware directly without using the BIOS.
2591
2592 With this option, you can specify how Linux should detect the
2593 PCI devices. If you choose "BIOS", the BIOS will be used,
2594 if you choose "Direct", the BIOS won't be used, and if you
2595 choose "MMConfig", then PCI Express MMCONFIG will be used.
2596 If you choose "Any", the kernel will try MMCONFIG, then the
2597 direct access method and falls back to the BIOS if that doesn't
2598 work. If unsure, go with the default, which is "Any".
2599
2600 config PCI_GOBIOS
2601 bool "BIOS"
2602
2603 config PCI_GOMMCONFIG
2604 bool "MMConfig"
2605
2606 config PCI_GODIRECT
2607 bool "Direct"
2608
2609 config PCI_GOOLPC
2610 bool "OLPC XO-1"
2611 depends on OLPC
2612
2613 config PCI_GOANY
2614 bool "Any"
2615
2616 endchoice
2617
2618 config PCI_BIOS
2619 def_bool y
2620 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2621
2622 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2623 config PCI_DIRECT
2624 def_bool y
2625 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2626
2627 config PCI_MMCONFIG
2628 bool "Support mmconfig PCI config space access" if X86_64
2629 default y
2630 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2631 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2632
2633 config PCI_OLPC
2634 def_bool y
2635 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2636
2637 config PCI_XEN
2638 def_bool y
2639 depends on PCI && XEN
2640 select SWIOTLB_XEN
2641
2642 config MMCONF_FAM10H
2643 def_bool y
2644 depends on X86_64 && PCI_MMCONFIG && ACPI
2645
2646 config PCI_CNB20LE_QUIRK
2647 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2648 depends on PCI
2649 help
2650 Read the PCI windows out of the CNB20LE host bridge. This allows
2651 PCI hotplug to work on systems with the CNB20LE chipset which do
2652 not have ACPI.
2653
2654 There's no public spec for this chipset, and this functionality
2655 is known to be incomplete.
2656
2657 You should say N unless you know you need this.
2658
2659 config ISA_BUS
2660 bool "ISA bus support on modern systems" if EXPERT
2661 help
2662 Expose ISA bus device drivers and options available for selection and
2663 configuration. Enable this option if your target machine has an ISA
2664 bus. ISA is an older system, displaced by PCI and newer bus
2665 architectures -- if your target machine is modern, it probably does
2666 not have an ISA bus.
2667
2668 If unsure, say N.
2669
2670 # x86_64 have no ISA slots, but can have ISA-style DMA.
2671 config ISA_DMA_API
2672 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2673 default y
2674 help
2675 Enables ISA-style DMA support for devices requiring such controllers.
2676 If unsure, say Y.
2677
2678 if X86_32
2679
2680 config ISA
2681 bool "ISA support"
2682 ---help---
2683 Find out whether you have ISA slots on your motherboard. ISA is the
2684 name of a bus system, i.e. the way the CPU talks to the other stuff
2685 inside your box. Other bus systems are PCI, EISA, MicroChannel
2686 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2687 newer boards don't support it. If you have ISA, say Y, otherwise N.
2688
2689 config SCx200
2690 tristate "NatSemi SCx200 support"
2691 ---help---
2692 This provides basic support for National Semiconductor's
2693 (now AMD's) Geode processors. The driver probes for the
2694 PCI-IDs of several on-chip devices, so its a good dependency
2695 for other scx200_* drivers.
2696
2697 If compiled as a module, the driver is named scx200.
2698
2699 config SCx200HR_TIMER
2700 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2701 depends on SCx200
2702 default y
2703 ---help---
2704 This driver provides a clocksource built upon the on-chip
2705 27MHz high-resolution timer. Its also a workaround for
2706 NSC Geode SC-1100's buggy TSC, which loses time when the
2707 processor goes idle (as is done by the scheduler). The
2708 other workaround is idle=poll boot option.
2709
2710 config OLPC
2711 bool "One Laptop Per Child support"
2712 depends on !X86_PAE
2713 select GPIOLIB
2714 select OF
2715 select OF_PROMTREE
2716 select IRQ_DOMAIN
2717 ---help---
2718 Add support for detecting the unique features of the OLPC
2719 XO hardware.
2720
2721 config OLPC_XO1_PM
2722 bool "OLPC XO-1 Power Management"
2723 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2724 ---help---
2725 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2726
2727 config OLPC_XO1_RTC
2728 bool "OLPC XO-1 Real Time Clock"
2729 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2730 ---help---
2731 Add support for the XO-1 real time clock, which can be used as a
2732 programmable wakeup source.
2733
2734 config OLPC_XO1_SCI
2735 bool "OLPC XO-1 SCI extras"
2736 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2737 depends on INPUT=y
2738 select POWER_SUPPLY
2739 ---help---
2740 Add support for SCI-based features of the OLPC XO-1 laptop:
2741 - EC-driven system wakeups
2742 - Power button
2743 - Ebook switch
2744 - Lid switch
2745 - AC adapter status updates
2746 - Battery status updates
2747
2748 config OLPC_XO15_SCI
2749 bool "OLPC XO-1.5 SCI extras"
2750 depends on OLPC && ACPI
2751 select POWER_SUPPLY
2752 ---help---
2753 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2754 - EC-driven system wakeups
2755 - AC adapter status updates
2756 - Battery status updates
2757
2758 config ALIX
2759 bool "PCEngines ALIX System Support (LED setup)"
2760 select GPIOLIB
2761 ---help---
2762 This option enables system support for the PCEngines ALIX.
2763 At present this just sets up LEDs for GPIO control on
2764 ALIX2/3/6 boards. However, other system specific setup should
2765 get added here.
2766
2767 Note: You must still enable the drivers for GPIO and LED support
2768 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2769
2770 Note: You have to set alix.force=1 for boards with Award BIOS.
2771
2772 config NET5501
2773 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2774 select GPIOLIB
2775 ---help---
2776 This option enables system support for the Soekris Engineering net5501.
2777
2778 config GEOS
2779 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2780 select GPIOLIB
2781 depends on DMI
2782 ---help---
2783 This option enables system support for the Traverse Technologies GEOS.
2784
2785 config TS5500
2786 bool "Technologic Systems TS-5500 platform support"
2787 depends on MELAN
2788 select CHECK_SIGNATURE
2789 select NEW_LEDS
2790 select LEDS_CLASS
2791 ---help---
2792 This option enables system support for the Technologic Systems TS-5500.
2793
2794 endif # X86_32
2795
2796 config AMD_NB
2797 def_bool y
2798 depends on CPU_SUP_AMD && PCI
2799
2800 config X86_SYSFB
2801 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2802 help
2803 Firmwares often provide initial graphics framebuffers so the BIOS,
2804 bootloader or kernel can show basic video-output during boot for
2805 user-guidance and debugging. Historically, x86 used the VESA BIOS
2806 Extensions and EFI-framebuffers for this, which are mostly limited
2807 to x86.
2808 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2809 framebuffers so the new generic system-framebuffer drivers can be
2810 used on x86. If the framebuffer is not compatible with the generic
2811 modes, it is advertised as fallback platform framebuffer so legacy
2812 drivers like efifb, vesafb and uvesafb can pick it up.
2813 If this option is not selected, all system framebuffers are always
2814 marked as fallback platform framebuffers as usual.
2815
2816 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2817 not be able to pick up generic system framebuffers if this option
2818 is selected. You are highly encouraged to enable simplefb as
2819 replacement if you select this option. simplefb can correctly deal
2820 with generic system framebuffers. But you should still keep vesafb
2821 and others enabled as fallback if a system framebuffer is
2822 incompatible with simplefb.
2823
2824 If unsure, say Y.
2825
2826 endmenu
2827
2828
2829 menu "Binary Emulations"
2830
2831 config IA32_EMULATION
2832 bool "IA32 Emulation"
2833 depends on X86_64
2834 select ARCH_WANT_OLD_COMPAT_IPC
2835 select BINFMT_ELF
2836 select COMPAT_BINFMT_ELF
2837 select COMPAT_OLD_SIGACTION
2838 ---help---
2839 Include code to run legacy 32-bit programs under a
2840 64-bit kernel. You should likely turn this on, unless you're
2841 100% sure that you don't have any 32-bit programs left.
2842
2843 config IA32_AOUT
2844 tristate "IA32 a.out support"
2845 depends on IA32_EMULATION
2846 ---help---
2847 Support old a.out binaries in the 32bit emulation.
2848
2849 config X86_X32
2850 bool "x32 ABI for 64-bit mode"
2851 depends on X86_64
2852 ---help---
2853 Include code to run binaries for the x32 native 32-bit ABI
2854 for 64-bit processors. An x32 process gets access to the
2855 full 64-bit register file and wide data path while leaving
2856 pointers at 32 bits for smaller memory footprint.
2857
2858 You will need a recent binutils (2.22 or later) with
2859 elf32_x86_64 support enabled to compile a kernel with this
2860 option set.
2861
2862 config COMPAT_32
2863 def_bool y
2864 depends on IA32_EMULATION || X86_32
2865 select HAVE_UID16
2866 select OLD_SIGSUSPEND3
2867
2868 config COMPAT
2869 def_bool y
2870 depends on IA32_EMULATION || X86_X32
2871
2872 if COMPAT
2873 config COMPAT_FOR_U64_ALIGNMENT
2874 def_bool y
2875
2876 config SYSVIPC_COMPAT
2877 def_bool y
2878 depends on SYSVIPC
2879 endif
2880
2881 endmenu
2882
2883
2884 config HAVE_ATOMIC_IOMAP
2885 def_bool y
2886 depends on X86_32
2887
2888 config X86_DEV_DMA_OPS
2889 bool
2890 depends on X86_64 || STA2X11
2891
2892 config X86_DMA_REMAP
2893 bool
2894 depends on STA2X11
2895
2896 config HAVE_GENERIC_GUP
2897 def_bool y
2898
2899 source "drivers/firmware/Kconfig"
2900
2901 source "arch/x86/kvm/Kconfig"