| blob | 1a0be022f91d8d6d89bc154642e3bd29619e483c |
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
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
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
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_DISCARD_MEMBLOCK
52 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
53 select ARCH_HAS_DEBUG_VIRTUAL
54 select ARCH_HAS_DEVMEM_IS_ALLOWED
55 select ARCH_HAS_ELF_RANDOMIZE
56 select ARCH_HAS_FAST_MULTIPLIER
57 select ARCH_HAS_FILTER_PGPROT
58 select ARCH_HAS_FORTIFY_SOURCE
59 select ARCH_HAS_GCOV_PROFILE_ALL
60 select ARCH_HAS_KCOV if X86_64
61 select ARCH_HAS_MEMBARRIER_SYNC_CORE
62 select ARCH_HAS_PMEM_API if X86_64
63 select ARCH_HAS_PTE_SPECIAL
64 select ARCH_HAS_REFCOUNT
65 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
66 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
67 select ARCH_HAS_SET_MEMORY
68 select ARCH_HAS_SG_CHAIN
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 DMA_DIRECT_OPS
93 select EDAC_ATOMIC_SCRUB
94 select EDAC_SUPPORT
95 select GENERIC_CLOCKEVENTS
96 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
97 select GENERIC_CLOCKEVENTS_MIN_ADJUST
98 select GENERIC_CMOS_UPDATE
99 select GENERIC_CPU_AUTOPROBE
100 select GENERIC_CPU_VULNERABILITIES
101 select GENERIC_EARLY_IOREMAP
102 select GENERIC_FIND_FIRST_BIT
103 select GENERIC_IOMAP
104 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
105 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
106 select GENERIC_IRQ_MIGRATION if SMP
107 select GENERIC_IRQ_PROBE
108 select GENERIC_IRQ_RESERVATION_MODE
109 select GENERIC_IRQ_SHOW
110 select GENERIC_PENDING_IRQ if SMP
111 select GENERIC_SMP_IDLE_THREAD
112 select GENERIC_STRNCPY_FROM_USER
113 select GENERIC_STRNLEN_USER
114 select GENERIC_TIME_VSYSCALL
115 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
116 select HAVE_ACPI_APEI if ACPI
117 select HAVE_ACPI_APEI_NMI if ACPI
118 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
119 select HAVE_ARCH_AUDITSYSCALL
120 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
121 select HAVE_ARCH_JUMP_LABEL
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_TRACEHOOK
131 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
132 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
133 select HAVE_ARCH_VMAP_STACK if X86_64
134 select HAVE_ARCH_WITHIN_STACK_FRAMES
135 select HAVE_CMPXCHG_DOUBLE
136 select HAVE_CMPXCHG_LOCAL
137 select HAVE_CONTEXT_TRACKING if X86_64
138 select HAVE_COPY_THREAD_TLS
139 select HAVE_C_RECORDMCOUNT
140 select HAVE_DEBUG_KMEMLEAK
141 select HAVE_DEBUG_STACKOVERFLOW
142 select HAVE_DMA_CONTIGUOUS
143 select HAVE_DYNAMIC_FTRACE
144 select HAVE_DYNAMIC_FTRACE_WITH_REGS
145 select HAVE_EBPF_JIT
146 select HAVE_EFFICIENT_UNALIGNED_ACCESS
147 select HAVE_EXIT_THREAD
148 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
149 select HAVE_FTRACE_MCOUNT_RECORD
150 select HAVE_FUNCTION_GRAPH_TRACER
151 select HAVE_FUNCTION_TRACER
152 select HAVE_GCC_PLUGINS
153 select HAVE_HW_BREAKPOINT
154 select HAVE_IDE
155 select HAVE_IOREMAP_PROT
156 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
157 select HAVE_IRQ_TIME_ACCOUNTING
158 select HAVE_KERNEL_BZIP2
159 select HAVE_KERNEL_GZIP
160 select HAVE_KERNEL_LZ4
161 select HAVE_KERNEL_LZMA
162 select HAVE_KERNEL_LZO
163 select HAVE_KERNEL_XZ
164 select HAVE_KPROBES
165 select HAVE_KPROBES_ON_FTRACE
166 select HAVE_FUNCTION_ERROR_INJECTION
167 select HAVE_KRETPROBES
168 select HAVE_KVM
169 select HAVE_LIVEPATCH if X86_64
170 select HAVE_MEMBLOCK
171 select HAVE_MEMBLOCK_NODE_MAP
172 select HAVE_MIXED_BREAKPOINTS_REGS
173 select HAVE_MOD_ARCH_SPECIFIC
174 select HAVE_NMI
175 select HAVE_OPROFILE
176 select HAVE_OPTPROBES
177 select HAVE_PCSPKR_PLATFORM
178 select HAVE_PERF_EVENTS
179 select HAVE_PERF_EVENTS_NMI
180 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
181 select HAVE_PERF_REGS
182 select HAVE_PERF_USER_STACK_DUMP
183 select HAVE_RCU_TABLE_FREE if PARAVIRT
184 select HAVE_RCU_TABLE_INVALIDATE if HAVE_RCU_TABLE_FREE
185 select HAVE_REGS_AND_STACK_ACCESS_API
186 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
187 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
188 select HAVE_STACK_VALIDATION if X86_64
189 select HAVE_RSEQ
190 select HAVE_SYSCALL_TRACEPOINTS
191 select HAVE_UNSTABLE_SCHED_CLOCK
192 select HAVE_USER_RETURN_NOTIFIER
193 select HOTPLUG_SMT if SMP
194 select IRQ_FORCED_THREADING
195 select NEED_SG_DMA_LENGTH
196 select PCI_LOCKLESS_CONFIG
197 select PERF_EVENTS
198 select RTC_LIB
199 select RTC_MC146818_LIB
200 select SPARSE_IRQ
201 select SRCU
202 select SYSCTL_EXCEPTION_TRACE
203 select THREAD_INFO_IN_TASK
204 select USER_STACKTRACE_SUPPORT
205 select VIRT_TO_BUS
206 select X86_FEATURE_NAMES if PROC_FS
208 config INSTRUCTION_DECODER
209 def_bool y
210 depends on KPROBES || PERF_EVENTS || UPROBES
212 config OUTPUT_FORMAT
213 string
214 default "elf32-i386" if X86_32
215 default "elf64-x86-64" if X86_64
217 config ARCH_DEFCONFIG
218 string
219 default "arch/x86/configs/i386_defconfig" if X86_32
220 default "arch/x86/configs/x86_64_defconfig" if X86_64
222 config LOCKDEP_SUPPORT
223 def_bool y
225 config STACKTRACE_SUPPORT
226 def_bool y
228 config MMU
229 def_bool y
231 config ARCH_MMAP_RND_BITS_MIN
232 default 28 if 64BIT
233 default 8
235 config ARCH_MMAP_RND_BITS_MAX
236 default 32 if 64BIT
237 default 16
239 config ARCH_MMAP_RND_COMPAT_BITS_MIN
240 default 8
242 config ARCH_MMAP_RND_COMPAT_BITS_MAX
243 default 16
245 config SBUS
246 bool
248 config GENERIC_ISA_DMA
249 def_bool y
250 depends on ISA_DMA_API
252 config GENERIC_BUG
253 def_bool y
254 depends on BUG
255 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
257 config GENERIC_BUG_RELATIVE_POINTERS
258 bool
260 config GENERIC_HWEIGHT
261 def_bool y
263 config ARCH_MAY_HAVE_PC_FDC
264 def_bool y
265 depends on ISA_DMA_API
267 config RWSEM_XCHGADD_ALGORITHM
268 def_bool y
270 config GENERIC_CALIBRATE_DELAY
271 def_bool y
273 config ARCH_HAS_CPU_RELAX
274 def_bool y
276 config ARCH_HAS_CACHE_LINE_SIZE
277 def_bool y
279 config ARCH_HAS_FILTER_PGPROT
280 def_bool y
282 config HAVE_SETUP_PER_CPU_AREA
283 def_bool y
285 config NEED_PER_CPU_EMBED_FIRST_CHUNK
286 def_bool y
288 config NEED_PER_CPU_PAGE_FIRST_CHUNK
289 def_bool y
291 config ARCH_HIBERNATION_POSSIBLE
292 def_bool y
294 config ARCH_SUSPEND_POSSIBLE
295 def_bool y
297 config ARCH_WANT_HUGE_PMD_SHARE
298 def_bool y
300 config ARCH_WANT_GENERAL_HUGETLB
301 def_bool y
303 config ZONE_DMA32
304 def_bool y if X86_64
306 config AUDIT_ARCH
307 def_bool y if X86_64
309 config ARCH_SUPPORTS_OPTIMIZED_INLINING
310 def_bool y
312 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
313 def_bool y
315 config KASAN_SHADOW_OFFSET
316 hex
317 depends on KASAN
318 default 0xdffffc0000000000
320 config HAVE_INTEL_TXT
321 def_bool y
322 depends on INTEL_IOMMU && ACPI
324 config X86_32_SMP
325 def_bool y
326 depends on X86_32 && SMP
328 config X86_64_SMP
329 def_bool y
330 depends on X86_64 && SMP
332 config X86_32_LAZY_GS
333 def_bool y
334 depends on X86_32 && !STACKPROTECTOR
336 config ARCH_SUPPORTS_UPROBES
337 def_bool y
339 config FIX_EARLYCON_MEM
340 def_bool y
342 config DYNAMIC_PHYSICAL_MASK
343 bool
345 config PGTABLE_LEVELS
346 int
347 default 5 if X86_5LEVEL
348 default 4 if X86_64
349 default 3 if X86_PAE
350 default 2
352 config CC_HAS_SANE_STACKPROTECTOR
353 bool
354 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
355 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
356 help
357 We have to make sure stack protector is unconditionally disabled if
358 the compiler produces broken code.
360 menu "Processor type and features"
362 config ZONE_DMA
363 bool "DMA memory allocation support" if EXPERT
364 default y
365 help
366 DMA memory allocation support allows devices with less than 32-bit
367 addressing to allocate within the first 16MB of address space.
368 Disable if no such devices will be used.
370 If unsure, say Y.
372 config SMP
373 bool "Symmetric multi-processing support"
374 ---help---
375 This enables support for systems with more than one CPU. If you have
376 a system with only one CPU, say N. If you have a system with more
377 than one CPU, say Y.
379 If you say N here, the kernel will run on uni- and multiprocessor
380 machines, but will use only one CPU of a multiprocessor machine. If
381 you say Y here, the kernel will run on many, but not all,
382 uniprocessor machines. On a uniprocessor machine, the kernel
383 will run faster if you say N here.
385 Note that if you say Y here and choose architecture "586" or
386 "Pentium" under "Processor family", the kernel will not work on 486
387 architectures. Similarly, multiprocessor kernels for the "PPro"
388 architecture may not work on all Pentium based boards.
390 People using multiprocessor machines who say Y here should also say
391 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
392 Management" code will be disabled if you say Y here.
394 See also <file:Documentation/x86/i386/IO-APIC.txt>,
395 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
396 <http://www.tldp.org/docs.html#howto>.
398 If you don't know what to do here, say N.
400 config X86_FEATURE_NAMES
401 bool "Processor feature human-readable names" if EMBEDDED
402 default y
403 ---help---
404 This option compiles in a table of x86 feature bits and corresponding
405 names. This is required to support /proc/cpuinfo and a few kernel
406 messages. You can disable this to save space, at the expense of
407 making those few kernel messages show numeric feature bits instead.
409 If in doubt, say Y.
411 config X86_X2APIC
412 bool "Support x2apic"
413 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
414 ---help---
415 This enables x2apic support on CPUs that have this feature.
417 This allows 32-bit apic IDs (so it can support very large systems),
418 and accesses the local apic via MSRs not via mmio.
420 If you don't know what to do here, say N.
422 config X86_MPPARSE
423 bool "Enable MPS table" if ACPI || SFI
424 default y
425 depends on X86_LOCAL_APIC
426 ---help---
427 For old smp systems that do not have proper acpi support. Newer systems
428 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
430 config GOLDFISH
431 def_bool y
432 depends on X86_GOLDFISH
434 config RETPOLINE
435 bool "Avoid speculative indirect branches in kernel"
436 default y
437 select STACK_VALIDATION if HAVE_STACK_VALIDATION
438 help
439 Compile kernel with the retpoline compiler options to guard against
440 kernel-to-user data leaks by avoiding speculative indirect
441 branches. Requires a compiler with -mindirect-branch=thunk-extern
442 support for full protection. The kernel may run slower.
444 Without compiler support, at least indirect branches in assembler
445 code are eliminated. Since this includes the syscall entry path,
446 it is not entirely pointless.
448 config INTEL_RDT
449 bool "Intel Resource Director Technology support"
450 default n
451 depends on X86 && CPU_SUP_INTEL
452 select KERNFS
453 help
454 Select to enable resource allocation and monitoring which are
455 sub-features of Intel Resource Director Technology(RDT). More
456 information about RDT can be found in the Intel x86
457 Architecture Software Developer Manual.
459 Say N if unsure.
461 if X86_32
462 config X86_BIGSMP
463 bool "Support for big SMP systems with more than 8 CPUs"
464 depends on SMP
465 ---help---
466 This option is needed for the systems that have more than 8 CPUs
468 config X86_EXTENDED_PLATFORM
469 bool "Support for extended (non-PC) x86 platforms"
470 default y
471 ---help---
472 If you disable this option then the kernel will only support
473 standard PC platforms. (which covers the vast majority of
474 systems out there.)
476 If you enable this option then you'll be able to select support
477 for the following (non-PC) 32 bit x86 platforms:
478 Goldfish (Android emulator)
479 AMD Elan
480 RDC R-321x SoC
481 SGI 320/540 (Visual Workstation)
482 STA2X11-based (e.g. Northville)
483 Moorestown MID devices
485 If you have one of these systems, or if you want to build a
486 generic distribution kernel, say Y here - otherwise say N.
487 endif
489 if X86_64
490 config X86_EXTENDED_PLATFORM
491 bool "Support for extended (non-PC) x86 platforms"
492 default y
493 ---help---
494 If you disable this option then the kernel will only support
495 standard PC platforms. (which covers the vast majority of
496 systems out there.)
498 If you enable this option then you'll be able to select support
499 for the following (non-PC) 64 bit x86 platforms:
500 Numascale NumaChip
501 ScaleMP vSMP
502 SGI Ultraviolet
504 If you have one of these systems, or if you want to build a
505 generic distribution kernel, say Y here - otherwise say N.
506 endif
507 # This is an alphabetically sorted list of 64 bit extended platforms
508 # Please maintain the alphabetic order if and when there are additions
509 config X86_NUMACHIP
510 bool "Numascale NumaChip"
511 depends on X86_64
512 depends on X86_EXTENDED_PLATFORM
513 depends on NUMA
514 depends on SMP
515 depends on X86_X2APIC
516 depends on PCI_MMCONFIG
517 ---help---
518 Adds support for Numascale NumaChip large-SMP systems. Needed to
519 enable more than ~168 cores.
520 If you don't have one of these, you should say N here.
522 config X86_VSMP
523 bool "ScaleMP vSMP"
524 select HYPERVISOR_GUEST
525 select PARAVIRT
526 depends on X86_64 && PCI
527 depends on X86_EXTENDED_PLATFORM
528 depends on SMP
529 ---help---
530 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
531 supposed to run on these EM64T-based machines. Only choose this option
532 if you have one of these machines.
534 config X86_UV
535 bool "SGI Ultraviolet"
536 depends on X86_64
537 depends on X86_EXTENDED_PLATFORM
538 depends on NUMA
539 depends on EFI
540 depends on X86_X2APIC
541 depends on PCI
542 ---help---
543 This option is needed in order to support SGI Ultraviolet systems.
544 If you don't have one of these, you should say N here.
546 # Following is an alphabetically sorted list of 32 bit extended platforms
547 # Please maintain the alphabetic order if and when there are additions
549 config X86_GOLDFISH
550 bool "Goldfish (Virtual Platform)"
551 depends on X86_EXTENDED_PLATFORM
552 ---help---
553 Enable support for the Goldfish virtual platform used primarily
554 for Android development. Unless you are building for the Android
555 Goldfish emulator say N here.
557 config X86_INTEL_CE
558 bool "CE4100 TV platform"
559 depends on PCI
560 depends on PCI_GODIRECT
561 depends on X86_IO_APIC
562 depends on X86_32
563 depends on X86_EXTENDED_PLATFORM
564 select X86_REBOOTFIXUPS
565 select OF
566 select OF_EARLY_FLATTREE
567 ---help---
568 Select for the Intel CE media processor (CE4100) SOC.
569 This option compiles in support for the CE4100 SOC for settop
570 boxes and media devices.
572 config X86_INTEL_MID
573 bool "Intel MID platform support"
574 depends on X86_EXTENDED_PLATFORM
575 depends on X86_PLATFORM_DEVICES
576 depends on PCI
577 depends on X86_64 || (PCI_GOANY && X86_32)
578 depends on X86_IO_APIC
579 select SFI
580 select I2C
581 select DW_APB_TIMER
582 select APB_TIMER
583 select INTEL_SCU_IPC
584 select MFD_INTEL_MSIC
585 ---help---
586 Select to build a kernel capable of supporting Intel MID (Mobile
587 Internet Device) platform systems which do not have the PCI legacy
588 interfaces. If you are building for a PC class system say N here.
590 Intel MID platforms are based on an Intel processor and chipset which
591 consume less power than most of the x86 derivatives.
593 config X86_INTEL_QUARK
594 bool "Intel Quark platform support"
595 depends on X86_32
596 depends on X86_EXTENDED_PLATFORM
597 depends on X86_PLATFORM_DEVICES
598 depends on X86_TSC
599 depends on PCI
600 depends on PCI_GOANY
601 depends on X86_IO_APIC
602 select IOSF_MBI
603 select INTEL_IMR
604 select COMMON_CLK
605 ---help---
606 Select to include support for Quark X1000 SoC.
607 Say Y here if you have a Quark based system such as the Arduino
608 compatible Intel Galileo.
610 config X86_INTEL_LPSS
611 bool "Intel Low Power Subsystem Support"
612 depends on X86 && ACPI
613 select COMMON_CLK
614 select PINCTRL
615 select IOSF_MBI
616 ---help---
617 Select to build support for Intel Low Power Subsystem such as
618 found on Intel Lynxpoint PCH. Selecting this option enables
619 things like clock tree (common clock framework) and pincontrol
620 which are needed by the LPSS peripheral drivers.
622 config X86_AMD_PLATFORM_DEVICE
623 bool "AMD ACPI2Platform devices support"
624 depends on ACPI
625 select COMMON_CLK
626 select PINCTRL
627 ---help---
628 Select to interpret AMD specific ACPI device to platform device
629 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
630 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
631 implemented under PINCTRL subsystem.
633 config IOSF_MBI
634 tristate "Intel SoC IOSF Sideband support for SoC platforms"
635 depends on PCI
636 ---help---
637 This option enables sideband register access support for Intel SoC
638 platforms. On these platforms the IOSF sideband is used in lieu of
639 MSR's for some register accesses, mostly but not limited to thermal
640 and power. Drivers may query the availability of this device to
641 determine if they need the sideband in order to work on these
642 platforms. The sideband is available on the following SoC products.
643 This list is not meant to be exclusive.
644 - BayTrail
645 - Braswell
646 - Quark
648 You should say Y if you are running a kernel on one of these SoC's.
650 config IOSF_MBI_DEBUG
651 bool "Enable IOSF sideband access through debugfs"
652 depends on IOSF_MBI && DEBUG_FS
653 ---help---
654 Select this option to expose the IOSF sideband access registers (MCR,
655 MDR, MCRX) through debugfs to write and read register information from
656 different units on the SoC. This is most useful for obtaining device
657 state information for debug and analysis. As this is a general access
658 mechanism, users of this option would have specific knowledge of the
659 device they want to access.
661 If you don't require the option or are in doubt, say N.
663 config X86_RDC321X
664 bool "RDC R-321x SoC"
665 depends on X86_32
666 depends on X86_EXTENDED_PLATFORM
667 select M486
668 select X86_REBOOTFIXUPS
669 ---help---
670 This option is needed for RDC R-321x system-on-chip, also known
671 as R-8610-(G).
672 If you don't have one of these chips, you should say N here.
674 config X86_32_NON_STANDARD
675 bool "Support non-standard 32-bit SMP architectures"
676 depends on X86_32 && SMP
677 depends on X86_EXTENDED_PLATFORM
678 ---help---
679 This option compiles in the bigsmp and STA2X11 default
680 subarchitectures. It is intended for a generic binary
681 kernel. If you select them all, kernel will probe it one by
682 one and will fallback to default.
684 # Alphabetically sorted list of Non standard 32 bit platforms
686 config X86_SUPPORTS_MEMORY_FAILURE
687 def_bool y
688 # MCE code calls memory_failure():
689 depends on X86_MCE
690 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
691 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
692 depends on X86_64 || !SPARSEMEM
693 select ARCH_SUPPORTS_MEMORY_FAILURE
695 config STA2X11
696 bool "STA2X11 Companion Chip Support"
697 depends on X86_32_NON_STANDARD && PCI
698 select ARCH_HAS_PHYS_TO_DMA
699 select X86_DEV_DMA_OPS
700 select X86_DMA_REMAP
701 select SWIOTLB
702 select MFD_STA2X11
703 select GPIOLIB
704 default n
705 ---help---
706 This adds support for boards based on the STA2X11 IO-Hub,
707 a.k.a. "ConneXt". The chip is used in place of the standard
708 PC chipset, so all "standard" peripherals are missing. If this
709 option is selected the kernel will still be able to boot on
710 standard PC machines.
712 config X86_32_IRIS
713 tristate "Eurobraille/Iris poweroff module"
714 depends on X86_32
715 ---help---
716 The Iris machines from EuroBraille do not have APM or ACPI support
717 to shut themselves down properly. A special I/O sequence is
718 needed to do so, which is what this module does at
719 kernel shutdown.
721 This is only for Iris machines from EuroBraille.
723 If unused, say N.
725 config SCHED_OMIT_FRAME_POINTER
726 def_bool y
727 prompt "Single-depth WCHAN output"
728 depends on X86
729 ---help---
730 Calculate simpler /proc/<PID>/wchan values. If this option
731 is disabled then wchan values will recurse back to the
732 caller function. This provides more accurate wchan values,
733 at the expense of slightly more scheduling overhead.
735 If in doubt, say "Y".
737 menuconfig HYPERVISOR_GUEST
738 bool "Linux guest support"
739 ---help---
740 Say Y here to enable options for running Linux under various hyper-
741 visors. This option enables basic hypervisor detection and platform
742 setup.
744 If you say N, all options in this submenu will be skipped and
745 disabled, and Linux guest support won't be built in.
747 if HYPERVISOR_GUEST
749 config PARAVIRT
750 bool "Enable paravirtualization code"
751 ---help---
752 This changes the kernel so it can modify itself when it is run
753 under a hypervisor, potentially improving performance significantly
754 over full virtualization. However, when run without a hypervisor
755 the kernel is theoretically slower and slightly larger.
757 config PARAVIRT_DEBUG
758 bool "paravirt-ops debugging"
759 depends on PARAVIRT && DEBUG_KERNEL
760 ---help---
761 Enable to debug paravirt_ops internals. Specifically, BUG if
762 a paravirt_op is missing when it is called.
764 config PARAVIRT_SPINLOCKS
765 bool "Paravirtualization layer for spinlocks"
766 depends on PARAVIRT && SMP
767 ---help---
768 Paravirtualized spinlocks allow a pvops backend to replace the
769 spinlock implementation with something virtualization-friendly
770 (for example, block the virtual CPU rather than spinning).
772 It has a minimal impact on native kernels and gives a nice performance
773 benefit on paravirtualized KVM / Xen kernels.
775 If you are unsure how to answer this question, answer Y.
777 config QUEUED_LOCK_STAT
778 bool "Paravirt queued spinlock statistics"
779 depends on PARAVIRT_SPINLOCKS && DEBUG_FS
780 ---help---
781 Enable the collection of statistical data on the slowpath
782 behavior of paravirtualized queued spinlocks and report
783 them on debugfs.
785 source "arch/x86/xen/Kconfig"
787 config KVM_GUEST
788 bool "KVM Guest support (including kvmclock)"
789 depends on PARAVIRT
790 select PARAVIRT_CLOCK
791 default y
792 ---help---
793 This option enables various optimizations for running under the KVM
794 hypervisor. It includes a paravirtualized clock, so that instead
795 of relying on a PIT (or probably other) emulation by the
796 underlying device model, the host provides the guest with
797 timing infrastructure such as time of day, and system time
799 config KVM_DEBUG_FS
800 bool "Enable debug information for KVM Guests in debugfs"
801 depends on KVM_GUEST && DEBUG_FS
802 default n
803 ---help---
804 This option enables collection of various statistics for KVM guest.
805 Statistics are displayed in debugfs filesystem. Enabling this option
806 may incur significant overhead.
808 config PARAVIRT_TIME_ACCOUNTING
809 bool "Paravirtual steal time accounting"
810 depends on PARAVIRT
811 default n
812 ---help---
813 Select this option to enable fine granularity task steal time
814 accounting. Time spent executing other tasks in parallel with
815 the current vCPU is discounted from the vCPU power. To account for
816 that, there can be a small performance impact.
818 If in doubt, say N here.
820 config PARAVIRT_CLOCK
821 bool
823 config JAILHOUSE_GUEST
824 bool "Jailhouse non-root cell support"
825 depends on X86_64 && PCI
826 select X86_PM_TIMER
827 ---help---
828 This option allows to run Linux as guest in a Jailhouse non-root
829 cell. You can leave this option disabled if you only want to start
830 Jailhouse and run Linux afterwards in the root cell.
832 endif #HYPERVISOR_GUEST
834 config NO_BOOTMEM
835 def_bool y
837 source "arch/x86/Kconfig.cpu"
839 config HPET_TIMER
840 def_bool X86_64
841 prompt "HPET Timer Support" if X86_32
842 ---help---
843 Use the IA-PC HPET (High Precision Event Timer) to manage
844 time in preference to the PIT and RTC, if a HPET is
845 present.
846 HPET is the next generation timer replacing legacy 8254s.
847 The HPET provides a stable time base on SMP
848 systems, unlike the TSC, but it is more expensive to access,
849 as it is off-chip. The interface used is documented
850 in the HPET spec, revision 1.
852 You can safely choose Y here. However, HPET will only be
853 activated if the platform and the BIOS support this feature.
854 Otherwise the 8254 will be used for timing services.
856 Choose N to continue using the legacy 8254 timer.
858 config HPET_EMULATE_RTC
859 def_bool y
860 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
862 config APB_TIMER
863 def_bool y if X86_INTEL_MID
864 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
865 select DW_APB_TIMER
866 depends on X86_INTEL_MID && SFI
867 help
868 APB timer is the replacement for 8254, HPET on X86 MID platforms.
869 The APBT provides a stable time base on SMP
870 systems, unlike the TSC, but it is more expensive to access,
871 as it is off-chip. APB timers are always running regardless of CPU
872 C states, they are used as per CPU clockevent device when possible.
874 # Mark as expert because too many people got it wrong.
875 # The code disables itself when not needed.
876 config DMI
877 default y
878 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
879 bool "Enable DMI scanning" if EXPERT
880 ---help---
881 Enabled scanning of DMI to identify machine quirks. Say Y
882 here unless you have verified that your setup is not
883 affected by entries in the DMI blacklist. Required by PNP
884 BIOS code.
886 config GART_IOMMU
887 bool "Old AMD GART IOMMU support"
888 select IOMMU_HELPER
889 select SWIOTLB
890 depends on X86_64 && PCI && AMD_NB
891 ---help---
892 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
893 GART based hardware IOMMUs.
895 The GART supports full DMA access for devices with 32-bit access
896 limitations, on systems with more than 3 GB. This is usually needed
897 for USB, sound, many IDE/SATA chipsets and some other devices.
899 Newer systems typically have a modern AMD IOMMU, supported via
900 the CONFIG_AMD_IOMMU=y config option.
902 In normal configurations this driver is only active when needed:
903 there's more than 3 GB of memory and the system contains a
904 32-bit limited device.
906 If unsure, say Y.
908 config CALGARY_IOMMU
909 bool "IBM Calgary IOMMU support"
910 select IOMMU_HELPER
911 select SWIOTLB
912 depends on X86_64 && PCI
913 ---help---
914 Support for hardware IOMMUs in IBM's xSeries x366 and x460
915 systems. Needed to run systems with more than 3GB of memory
916 properly with 32-bit PCI devices that do not support DAC
917 (Double Address Cycle). Calgary also supports bus level
918 isolation, where all DMAs pass through the IOMMU. This
919 prevents them from going anywhere except their intended
920 destination. This catches hard-to-find kernel bugs and
921 mis-behaving drivers and devices that do not use the DMA-API
922 properly to set up their DMA buffers. The IOMMU can be
923 turned off at boot time with the iommu=off parameter.
924 Normally the kernel will make the right choice by itself.
925 If unsure, say Y.
927 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
928 def_bool y
929 prompt "Should Calgary be enabled by default?"
930 depends on CALGARY_IOMMU
931 ---help---
932 Should Calgary be enabled by default? if you choose 'y', Calgary
933 will be used (if it exists). If you choose 'n', Calgary will not be
934 used even if it exists. If you choose 'n' and would like to use
935 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
936 If unsure, say Y.
938 config MAXSMP
939 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
940 depends on X86_64 && SMP && DEBUG_KERNEL
941 select CPUMASK_OFFSTACK
942 ---help---
943 Enable maximum number of CPUS and NUMA Nodes for this architecture.
944 If unsure, say N.
946 #
947 # The maximum number of CPUs supported:
948 #
949 # The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
950 # and which can be configured interactively in the
951 # [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
952 #
953 # The ranges are different on 32-bit and 64-bit kernels, depending on
954 # hardware capabilities and scalability features of the kernel.
955 #
956 # ( If MAXSMP is enabled we just use the highest possible value and disable
957 # interactive configuration. )
958 #
960 config NR_CPUS_RANGE_BEGIN
961 int
962 default NR_CPUS_RANGE_END if MAXSMP
963 default 1 if !SMP
964 default 2
966 config NR_CPUS_RANGE_END
967 int
968 depends on X86_32
969 default 64 if SMP && X86_BIGSMP
970 default 8 if SMP && !X86_BIGSMP
971 default 1 if !SMP
973 config NR_CPUS_RANGE_END
974 int
975 depends on X86_64
976 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK)
977 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
978 default 1 if !SMP
980 config NR_CPUS_DEFAULT
981 int
982 depends on X86_32
983 default 32 if X86_BIGSMP
984 default 8 if SMP
985 default 1 if !SMP
987 config NR_CPUS_DEFAULT
988 int
989 depends on X86_64
990 default 8192 if MAXSMP
991 default 64 if SMP
992 default 1 if !SMP
994 config NR_CPUS
995 int "Maximum number of CPUs" if SMP && !MAXSMP
996 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
997 default NR_CPUS_DEFAULT
998 ---help---
999 This allows you to specify the maximum number of CPUs which this
1000 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
1001 supported value is 8192, otherwise the maximum value is 512. The
1002 minimum value which makes sense is 2.
1004 This is purely to save memory: each supported CPU adds about 8KB
1005 to the kernel image.
1007 config SCHED_SMT
1008 bool "SMT (Hyperthreading) scheduler support"
1009 depends on SMP
1010 ---help---
1011 SMT scheduler support improves the CPU scheduler's decision making
1012 when dealing with Intel Pentium 4 chips with HyperThreading at a
1013 cost of slightly increased overhead in some places. If unsure say
1014 N here.
1016 config SCHED_MC
1017 def_bool y
1018 prompt "Multi-core scheduler support"
1019 depends on SMP
1020 ---help---
1021 Multi-core scheduler support improves the CPU scheduler's decision
1022 making when dealing with multi-core CPU chips at a cost of slightly
1023 increased overhead in some places. If unsure say N here.
1025 config SCHED_MC_PRIO
1026 bool "CPU core priorities scheduler support"
1027 depends on SCHED_MC && CPU_SUP_INTEL
1028 select X86_INTEL_PSTATE
1029 select CPU_FREQ
1030 default y
1031 ---help---
1032 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1033 core ordering determined at manufacturing time, which allows
1034 certain cores to reach higher turbo frequencies (when running
1035 single threaded workloads) than others.
1037 Enabling this kernel feature teaches the scheduler about
1038 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1039 scheduler's CPU selection logic accordingly, so that higher
1040 overall system performance can be achieved.
1042 This feature will have no effect on CPUs without this feature.
1044 If unsure say Y here.
1046 config UP_LATE_INIT
1047 def_bool y
1048 depends on !SMP && X86_LOCAL_APIC
1050 config X86_UP_APIC
1051 bool "Local APIC support on uniprocessors" if !PCI_MSI
1052 default PCI_MSI
1053 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1054 ---help---
1055 A local APIC (Advanced Programmable Interrupt Controller) is an
1056 integrated interrupt controller in the CPU. If you have a single-CPU
1057 system which has a processor with a local APIC, you can say Y here to
1058 enable and use it. If you say Y here even though your machine doesn't
1059 have a local APIC, then the kernel will still run with no slowdown at
1060 all. The local APIC supports CPU-generated self-interrupts (timer,
1061 performance counters), and the NMI watchdog which detects hard
1062 lockups.
1064 config X86_UP_IOAPIC
1065 bool "IO-APIC support on uniprocessors"
1066 depends on X86_UP_APIC
1067 ---help---
1068 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1069 SMP-capable replacement for PC-style interrupt controllers. Most
1070 SMP systems and many recent uniprocessor systems have one.
1072 If you have a single-CPU system with an IO-APIC, you can say Y here
1073 to use it. If you say Y here even though your machine doesn't have
1074 an IO-APIC, then the kernel will still run with no slowdown at all.
1076 config X86_LOCAL_APIC
1077 def_bool y
1078 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1079 select IRQ_DOMAIN_HIERARCHY
1080 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1082 config X86_IO_APIC
1083 def_bool y
1084 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1086 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1087 bool "Reroute for broken boot IRQs"
1088 depends on X86_IO_APIC
1089 ---help---
1090 This option enables a workaround that fixes a source of
1091 spurious interrupts. This is recommended when threaded
1092 interrupt handling is used on systems where the generation of
1093 superfluous "boot interrupts" cannot be disabled.
1095 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1096 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1097 kernel does during interrupt handling). On chipsets where this
1098 boot IRQ generation cannot be disabled, this workaround keeps
1099 the original IRQ line masked so that only the equivalent "boot
1100 IRQ" is delivered to the CPUs. The workaround also tells the
1101 kernel to set up the IRQ handler on the boot IRQ line. In this
1102 way only one interrupt is delivered to the kernel. Otherwise
1103 the spurious second interrupt may cause the kernel to bring
1104 down (vital) interrupt lines.
1106 Only affects "broken" chipsets. Interrupt sharing may be
1107 increased on these systems.
1109 config X86_MCE
1110 bool "Machine Check / overheating reporting"
1111 select GENERIC_ALLOCATOR
1112 default y
1113 ---help---
1114 Machine Check support allows the processor to notify the
1115 kernel if it detects a problem (e.g. overheating, data corruption).
1116 The action the kernel takes depends on the severity of the problem,
1117 ranging from warning messages to halting the machine.
1119 config X86_MCELOG_LEGACY
1120 bool "Support for deprecated /dev/mcelog character device"
1121 depends on X86_MCE
1122 ---help---
1123 Enable support for /dev/mcelog which is needed by the old mcelog
1124 userspace logging daemon. Consider switching to the new generation
1125 rasdaemon solution.
1127 config X86_MCE_INTEL
1128 def_bool y
1129 prompt "Intel MCE features"
1130 depends on X86_MCE && X86_LOCAL_APIC
1131 ---help---
1132 Additional support for intel specific MCE features such as
1133 the thermal monitor.
1135 config X86_MCE_AMD
1136 def_bool y
1137 prompt "AMD MCE features"
1138 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1139 ---help---
1140 Additional support for AMD specific MCE features such as
1141 the DRAM Error Threshold.
1143 config X86_ANCIENT_MCE
1144 bool "Support for old Pentium 5 / WinChip machine checks"
1145 depends on X86_32 && X86_MCE
1146 ---help---
1147 Include support for machine check handling on old Pentium 5 or WinChip
1148 systems. These typically need to be enabled explicitly on the command
1149 line.
1151 config X86_MCE_THRESHOLD
1152 depends on X86_MCE_AMD || X86_MCE_INTEL
1153 def_bool y
1155 config X86_MCE_INJECT
1156 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1157 tristate "Machine check injector support"
1158 ---help---
1159 Provide support for injecting machine checks for testing purposes.
1160 If you don't know what a machine check is and you don't do kernel
1161 QA it is safe to say n.
1163 config X86_THERMAL_VECTOR
1164 def_bool y
1165 depends on X86_MCE_INTEL
1167 source "arch/x86/events/Kconfig"
1169 config X86_LEGACY_VM86
1170 bool "Legacy VM86 support"
1171 default n
1172 depends on X86_32
1173 ---help---
1174 This option allows user programs to put the CPU into V8086
1175 mode, which is an 80286-era approximation of 16-bit real mode.
1177 Some very old versions of X and/or vbetool require this option
1178 for user mode setting. Similarly, DOSEMU will use it if
1179 available to accelerate real mode DOS programs. However, any
1180 recent version of DOSEMU, X, or vbetool should be fully
1181 functional even without kernel VM86 support, as they will all
1182 fall back to software emulation. Nevertheless, if you are using
1183 a 16-bit DOS program where 16-bit performance matters, vm86
1184 mode might be faster than emulation and you might want to
1185 enable this option.
1187 Note that any app that works on a 64-bit kernel is unlikely to
1188 need this option, as 64-bit kernels don't, and can't, support
1189 V8086 mode. This option is also unrelated to 16-bit protected
1190 mode and is not needed to run most 16-bit programs under Wine.
1192 Enabling this option increases the complexity of the kernel
1193 and slows down exception handling a tiny bit.
1195 If unsure, say N here.
1197 config VM86
1198 bool
1199 default X86_LEGACY_VM86
1201 config X86_16BIT
1202 bool "Enable support for 16-bit segments" if EXPERT
1203 default y
1204 depends on MODIFY_LDT_SYSCALL
1205 ---help---
1206 This option is required by programs like Wine to run 16-bit
1207 protected mode legacy code on x86 processors. Disabling
1208 this option saves about 300 bytes on i386, or around 6K text
1209 plus 16K runtime memory on x86-64,
1211 config X86_ESPFIX32
1212 def_bool y
1213 depends on X86_16BIT && X86_32
1215 config X86_ESPFIX64
1216 def_bool y
1217 depends on X86_16BIT && X86_64
1219 config X86_VSYSCALL_EMULATION
1220 bool "Enable vsyscall emulation" if EXPERT
1221 default y
1222 depends on X86_64
1223 ---help---
1224 This enables emulation of the legacy vsyscall page. Disabling
1225 it is roughly equivalent to booting with vsyscall=none, except
1226 that it will also disable the helpful warning if a program
1227 tries to use a vsyscall. With this option set to N, offending
1228 programs will just segfault, citing addresses of the form
1229 0xffffffffff600?00.
1231 This option is required by many programs built before 2013, and
1232 care should be used even with newer programs if set to N.
1234 Disabling this option saves about 7K of kernel size and
1235 possibly 4K of additional runtime pagetable memory.
1237 config TOSHIBA
1238 tristate "Toshiba Laptop support"
1239 depends on X86_32
1240 ---help---
1241 This adds a driver to safely access the System Management Mode of
1242 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1243 not work on models with a Phoenix BIOS. The System Management Mode
1244 is used to set the BIOS and power saving options on Toshiba portables.
1246 For information on utilities to make use of this driver see the
1247 Toshiba Linux utilities web site at:
1248 <http://www.buzzard.org.uk/toshiba/>.
1250 Say Y if you intend to run this kernel on a Toshiba portable.
1251 Say N otherwise.
1253 config I8K
1254 tristate "Dell i8k legacy laptop support"
1255 select HWMON
1256 select SENSORS_DELL_SMM
1257 ---help---
1258 This option enables legacy /proc/i8k userspace interface in hwmon
1259 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1260 temperature and allows controlling fan speeds of Dell laptops via
1261 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1262 it reports also power and hotkey status. For fan speed control is
1263 needed userspace package i8kutils.
1265 Say Y if you intend to run this kernel on old Dell laptops or want to
1266 use userspace package i8kutils.
1267 Say N otherwise.
1269 config X86_REBOOTFIXUPS
1270 bool "Enable X86 board specific fixups for reboot"
1271 depends on X86_32
1272 ---help---
1273 This enables chipset and/or board specific fixups to be done
1274 in order to get reboot to work correctly. This is only needed on
1275 some combinations of hardware and BIOS. The symptom, for which
1276 this config is intended, is when reboot ends with a stalled/hung
1277 system.
1279 Currently, the only fixup is for the Geode machines using
1280 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1282 Say Y if you want to enable the fixup. Currently, it's safe to
1283 enable this option even if you don't need it.
1284 Say N otherwise.
1286 config MICROCODE
1287 bool "CPU microcode loading support"
1288 default y
1289 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1290 select FW_LOADER
1291 ---help---
1292 If you say Y here, you will be able to update the microcode on
1293 Intel and AMD processors. The Intel support is for the IA32 family,
1294 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1295 AMD support is for families 0x10 and later. You will obviously need
1296 the actual microcode binary data itself which is not shipped with
1297 the Linux kernel.
1299 The preferred method to load microcode from a detached initrd is described
1300 in Documentation/x86/microcode.txt. For that you need to enable
1301 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1302 initrd for microcode blobs.
1304 In addition, you can build the microcode into the kernel. For that you
1305 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1306 config option.
1308 config MICROCODE_INTEL
1309 bool "Intel microcode loading support"
1310 depends on MICROCODE
1311 default MICROCODE
1312 select FW_LOADER
1313 ---help---
1314 This options enables microcode patch loading support for Intel
1315 processors.
1317 For the current Intel microcode data package go to
1318 <https://downloadcenter.intel.com> and search for
1319 'Linux Processor Microcode Data File'.
1321 config MICROCODE_AMD
1322 bool "AMD microcode loading support"
1323 depends on MICROCODE
1324 select FW_LOADER
1325 ---help---
1326 If you select this option, microcode patch loading support for AMD
1327 processors will be enabled.
1329 config MICROCODE_OLD_INTERFACE
1330 def_bool y
1331 depends on MICROCODE
1333 config X86_MSR
1334 tristate "/dev/cpu/*/msr - Model-specific register support"
1335 ---help---
1336 This device gives privileged processes access to the x86
1337 Model-Specific Registers (MSRs). It is a character device with
1338 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1339 MSR accesses are directed to a specific CPU on multi-processor
1340 systems.
1342 config X86_CPUID
1343 tristate "/dev/cpu/*/cpuid - CPU information support"
1344 ---help---
1345 This device gives processes access to the x86 CPUID instruction to
1346 be executed on a specific processor. It is a character device
1347 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1348 /dev/cpu/31/cpuid.
1350 choice
1351 prompt "High Memory Support"
1352 default HIGHMEM4G
1353 depends on X86_32
1355 config NOHIGHMEM
1356 bool "off"
1357 ---help---
1358 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1359 However, the address space of 32-bit x86 processors is only 4
1360 Gigabytes large. That means that, if you have a large amount of
1361 physical memory, not all of it can be "permanently mapped" by the
1362 kernel. The physical memory that's not permanently mapped is called
1363 "high memory".
1365 If you are compiling a kernel which will never run on a machine with
1366 more than 1 Gigabyte total physical RAM, answer "off" here (default
1367 choice and suitable for most users). This will result in a "3GB/1GB"
1368 split: 3GB are mapped so that each process sees a 3GB virtual memory
1369 space and the remaining part of the 4GB virtual memory space is used
1370 by the kernel to permanently map as much physical memory as
1371 possible.
1373 If the machine has between 1 and 4 Gigabytes physical RAM, then
1374 answer "4GB" here.
1376 If more than 4 Gigabytes is used then answer "64GB" here. This
1377 selection turns Intel PAE (Physical Address Extension) mode on.
1378 PAE implements 3-level paging on IA32 processors. PAE is fully
1379 supported by Linux, PAE mode is implemented on all recent Intel
1380 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1381 then the kernel will not boot on CPUs that don't support PAE!
1383 The actual amount of total physical memory will either be
1384 auto detected or can be forced by using a kernel command line option
1385 such as "mem=256M". (Try "man bootparam" or see the documentation of
1386 your boot loader (lilo or loadlin) about how to pass options to the
1387 kernel at boot time.)
1389 If unsure, say "off".
1391 config HIGHMEM4G
1392 bool "4GB"
1393 ---help---
1394 Select this if you have a 32-bit processor and between 1 and 4
1395 gigabytes of physical RAM.
1397 config HIGHMEM64G
1398 bool "64GB"
1399 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1400 select X86_PAE
1401 ---help---
1402 Select this if you have a 32-bit processor and more than 4
1403 gigabytes of physical RAM.
1405 endchoice
1407 choice
1408 prompt "Memory split" if EXPERT
1409 default VMSPLIT_3G
1410 depends on X86_32
1411 ---help---
1412 Select the desired split between kernel and user memory.
1414 If the address range available to the kernel is less than the
1415 physical memory installed, the remaining memory will be available
1416 as "high memory". Accessing high memory is a little more costly
1417 than low memory, as it needs to be mapped into the kernel first.
1418 Note that increasing the kernel address space limits the range
1419 available to user programs, making the address space there
1420 tighter. Selecting anything other than the default 3G/1G split
1421 will also likely make your kernel incompatible with binary-only
1422 kernel modules.
1424 If you are not absolutely sure what you are doing, leave this
1425 option alone!
1427 config VMSPLIT_3G
1428 bool "3G/1G user/kernel split"
1429 config VMSPLIT_3G_OPT
1430 depends on !X86_PAE
1431 bool "3G/1G user/kernel split (for full 1G low memory)"
1432 config VMSPLIT_2G
1433 bool "2G/2G user/kernel split"
1434 config VMSPLIT_2G_OPT
1435 depends on !X86_PAE
1436 bool "2G/2G user/kernel split (for full 2G low memory)"
1437 config VMSPLIT_1G
1438 bool "1G/3G user/kernel split"
1439 endchoice
1441 config PAGE_OFFSET
1442 hex
1443 default 0xB0000000 if VMSPLIT_3G_OPT
1444 default 0x80000000 if VMSPLIT_2G
1445 default 0x78000000 if VMSPLIT_2G_OPT
1446 default 0x40000000 if VMSPLIT_1G
1447 default 0xC0000000
1448 depends on X86_32
1450 config HIGHMEM
1451 def_bool y
1452 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1454 config X86_PAE
1455 bool "PAE (Physical Address Extension) Support"
1456 depends on X86_32 && !HIGHMEM4G
1457 select PHYS_ADDR_T_64BIT
1458 select SWIOTLB
1459 ---help---
1460 PAE is required for NX support, and furthermore enables
1461 larger swapspace support for non-overcommit purposes. It
1462 has the cost of more pagetable lookup overhead, and also
1463 consumes more pagetable space per process.
1465 config X86_5LEVEL
1466 bool "Enable 5-level page tables support"
1467 select DYNAMIC_MEMORY_LAYOUT
1468 select SPARSEMEM_VMEMMAP
1469 depends on X86_64
1470 ---help---
1471 5-level paging enables access to larger address space:
1472 upto 128 PiB of virtual address space and 4 PiB of
1473 physical address space.
1475 It will be supported by future Intel CPUs.
1477 A kernel with the option enabled can be booted on machines that
1478 support 4- or 5-level paging.
1480 See Documentation/x86/x86_64/5level-paging.txt for more
1481 information.
1483 Say N if unsure.
1485 config X86_DIRECT_GBPAGES
1486 def_bool y
1487 depends on X86_64 && !DEBUG_PAGEALLOC
1488 ---help---
1489 Certain kernel features effectively disable kernel
1490 linear 1 GB mappings (even if the CPU otherwise
1491 supports them), so don't confuse the user by printing
1492 that we have them enabled.
1494 config ARCH_HAS_MEM_ENCRYPT
1495 def_bool y
1497 config AMD_MEM_ENCRYPT
1498 bool "AMD Secure Memory Encryption (SME) support"
1499 depends on X86_64 && CPU_SUP_AMD
1500 select DYNAMIC_PHYSICAL_MASK
1501 ---help---
1502 Say yes to enable support for the encryption of system memory.
1503 This requires an AMD processor that supports Secure Memory
1504 Encryption (SME).
1506 config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1507 bool "Activate AMD Secure Memory Encryption (SME) by default"
1508 default y
1509 depends on AMD_MEM_ENCRYPT
1510 ---help---
1511 Say yes to have system memory encrypted by default if running on
1512 an AMD processor that supports Secure Memory Encryption (SME).
1514 If set to Y, then the encryption of system memory can be
1515 deactivated with the mem_encrypt=off command line option.
1517 If set to N, then the encryption of system memory can be
1518 activated with the mem_encrypt=on command line option.
1520 config ARCH_USE_MEMREMAP_PROT
1521 def_bool y
1522 depends on AMD_MEM_ENCRYPT
1524 # Common NUMA Features
1525 config NUMA
1526 bool "Numa Memory Allocation and Scheduler Support"
1527 depends on SMP
1528 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1529 default y if X86_BIGSMP
1530 ---help---
1531 Enable NUMA (Non Uniform Memory Access) support.
1533 The kernel will try to allocate memory used by a CPU on the
1534 local memory controller of the CPU and add some more
1535 NUMA awareness to the kernel.
1537 For 64-bit this is recommended if the system is Intel Core i7
1538 (or later), AMD Opteron, or EM64T NUMA.
1540 For 32-bit this is only needed if you boot a 32-bit
1541 kernel on a 64-bit NUMA platform.
1543 Otherwise, you should say N.
1545 config AMD_NUMA
1546 def_bool y
1547 prompt "Old style AMD Opteron NUMA detection"
1548 depends on X86_64 && NUMA && PCI
1549 ---help---
1550 Enable AMD NUMA node topology detection. You should say Y here if
1551 you have a multi processor AMD system. This uses an old method to
1552 read the NUMA configuration directly from the builtin Northbridge
1553 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1554 which also takes priority if both are compiled in.
1556 config X86_64_ACPI_NUMA
1557 def_bool y
1558 prompt "ACPI NUMA detection"
1559 depends on X86_64 && NUMA && ACPI && PCI
1560 select ACPI_NUMA
1561 ---help---
1562 Enable ACPI SRAT based node topology detection.
1564 # Some NUMA nodes have memory ranges that span
1565 # other nodes. Even though a pfn is valid and
1566 # between a node's start and end pfns, it may not
1567 # reside on that node. See memmap_init_zone()
1568 # for details.
1569 config NODES_SPAN_OTHER_NODES
1570 def_bool y
1571 depends on X86_64_ACPI_NUMA
1573 config NUMA_EMU
1574 bool "NUMA emulation"
1575 depends on NUMA
1576 ---help---
1577 Enable NUMA emulation. A flat machine will be split
1578 into virtual nodes when booted with "numa=fake=N", where N is the
1579 number of nodes. This is only useful for debugging.
1581 config NODES_SHIFT
1582 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1583 range 1 10
1584 default "10" if MAXSMP
1585 default "6" if X86_64
1586 default "3"
1587 depends on NEED_MULTIPLE_NODES
1588 ---help---
1589 Specify the maximum number of NUMA Nodes available on the target
1590 system. Increases memory reserved to accommodate various tables.
1592 config ARCH_HAVE_MEMORY_PRESENT
1593 def_bool y
1594 depends on X86_32 && DISCONTIGMEM
1596 config ARCH_FLATMEM_ENABLE
1597 def_bool y
1598 depends on X86_32 && !NUMA
1600 config ARCH_DISCONTIGMEM_ENABLE
1601 def_bool y
1602 depends on NUMA && X86_32
1604 config ARCH_DISCONTIGMEM_DEFAULT
1605 def_bool y
1606 depends on NUMA && X86_32
1608 config ARCH_SPARSEMEM_ENABLE
1609 def_bool y
1610 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1611 select SPARSEMEM_STATIC if X86_32
1612 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1614 config ARCH_SPARSEMEM_DEFAULT
1615 def_bool y
1616 depends on X86_64
1618 config ARCH_SELECT_MEMORY_MODEL
1619 def_bool y
1620 depends on ARCH_SPARSEMEM_ENABLE
1622 config ARCH_MEMORY_PROBE
1623 bool "Enable sysfs memory/probe interface"
1624 depends on X86_64 && MEMORY_HOTPLUG
1625 help
1626 This option enables a sysfs memory/probe interface for testing.
1627 See Documentation/memory-hotplug.txt for more information.
1628 If you are unsure how to answer this question, answer N.
1630 config ARCH_PROC_KCORE_TEXT
1631 def_bool y
1632 depends on X86_64 && PROC_KCORE
1634 config ILLEGAL_POINTER_VALUE
1635 hex
1636 default 0 if X86_32
1637 default 0xdead000000000000 if X86_64
1639 config X86_PMEM_LEGACY_DEVICE
1640 bool
1642 config X86_PMEM_LEGACY
1643 tristate "Support non-standard NVDIMMs and ADR protected memory"
1644 depends on PHYS_ADDR_T_64BIT
1645 depends on BLK_DEV
1646 select X86_PMEM_LEGACY_DEVICE
1647 select LIBNVDIMM
1648 help
1649 Treat memory marked using the non-standard e820 type of 12 as used
1650 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1651 The kernel will offer these regions to the 'pmem' driver so
1652 they can be used for persistent storage.
1654 Say Y if unsure.
1656 config HIGHPTE
1657 bool "Allocate 3rd-level pagetables from highmem"
1658 depends on HIGHMEM
1659 ---help---
1660 The VM uses one page table entry for each page of physical memory.
1661 For systems with a lot of RAM, this can be wasteful of precious
1662 low memory. Setting this option will put user-space page table
1663 entries in high memory.
1665 config X86_CHECK_BIOS_CORRUPTION
1666 bool "Check for low memory corruption"
1667 ---help---
1668 Periodically check for memory corruption in low memory, which
1669 is suspected to be caused by BIOS. Even when enabled in the
1670 configuration, it is disabled at runtime. Enable it by
1671 setting "memory_corruption_check=1" on the kernel command
1672 line. By default it scans the low 64k of memory every 60
1673 seconds; see the memory_corruption_check_size and
1674 memory_corruption_check_period parameters in
1675 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1677 When enabled with the default parameters, this option has
1678 almost no overhead, as it reserves a relatively small amount
1679 of memory and scans it infrequently. It both detects corruption
1680 and prevents it from affecting the running system.
1682 It is, however, intended as a diagnostic tool; if repeatable
1683 BIOS-originated corruption always affects the same memory,
1684 you can use memmap= to prevent the kernel from using that
1685 memory.
1687 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1688 bool "Set the default setting of memory_corruption_check"
1689 depends on X86_CHECK_BIOS_CORRUPTION
1690 default y
1691 ---help---
1692 Set whether the default state of memory_corruption_check is
1693 on or off.
1695 config X86_RESERVE_LOW
1696 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1697 default 64
1698 range 4 640
1699 ---help---
1700 Specify the amount of low memory to reserve for the BIOS.
1702 The first page contains BIOS data structures that the kernel
1703 must not use, so that page must always be reserved.
1705 By default we reserve the first 64K of physical RAM, as a
1706 number of BIOSes are known to corrupt that memory range
1707 during events such as suspend/resume or monitor cable
1708 insertion, so it must not be used by the kernel.
1710 You can set this to 4 if you are absolutely sure that you
1711 trust the BIOS to get all its memory reservations and usages
1712 right. If you know your BIOS have problems beyond the
1713 default 64K area, you can set this to 640 to avoid using the
1714 entire low memory range.
1716 If you have doubts about the BIOS (e.g. suspend/resume does
1717 not work or there's kernel crashes after certain hardware
1718 hotplug events) then you might want to enable
1719 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1720 typical corruption patterns.
1722 Leave this to the default value of 64 if you are unsure.
1724 config MATH_EMULATION
1725 bool
1726 depends on MODIFY_LDT_SYSCALL
1727 prompt "Math emulation" if X86_32
1728 ---help---
1729 Linux can emulate a math coprocessor (used for floating point
1730 operations) if you don't have one. 486DX and Pentium processors have
1731 a math coprocessor built in, 486SX and 386 do not, unless you added
1732 a 487DX or 387, respectively. (The messages during boot time can
1733 give you some hints here ["man dmesg"].) Everyone needs either a
1734 coprocessor or this emulation.
1736 If you don't have a math coprocessor, you need to say Y here; if you
1737 say Y here even though you have a coprocessor, the coprocessor will
1738 be used nevertheless. (This behavior can be changed with the kernel
1739 command line option "no387", which comes handy if your coprocessor
1740 is broken. Try "man bootparam" or see the documentation of your boot
1741 loader (lilo or loadlin) about how to pass options to the kernel at
1742 boot time.) This means that it is a good idea to say Y here if you
1743 intend to use this kernel on different machines.
1745 More information about the internals of the Linux math coprocessor
1746 emulation can be found in <file:arch/x86/math-emu/README>.
1748 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1749 kernel, it won't hurt.
1751 config MTRR
1752 def_bool y
1753 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1754 ---help---
1755 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1756 the Memory Type Range Registers (MTRRs) may be used to control
1757 processor access to memory ranges. This is most useful if you have
1758 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1759 allows bus write transfers to be combined into a larger transfer
1760 before bursting over the PCI/AGP bus. This can increase performance
1761 of image write operations 2.5 times or more. Saying Y here creates a
1762 /proc/mtrr file which may be used to manipulate your processor's
1763 MTRRs. Typically the X server should use this.
1765 This code has a reasonably generic interface so that similar
1766 control registers on other processors can be easily supported
1767 as well:
1769 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1770 Registers (ARRs) which provide a similar functionality to MTRRs. For
1771 these, the ARRs are used to emulate the MTRRs.
1772 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1773 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1774 write-combining. All of these processors are supported by this code
1775 and it makes sense to say Y here if you have one of them.
1777 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1778 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1779 can lead to all sorts of problems, so it's good to say Y here.
1781 You can safely say Y even if your machine doesn't have MTRRs, you'll
1782 just add about 9 KB to your kernel.
1784 See <file:Documentation/x86/mtrr.txt> for more information.
1786 config MTRR_SANITIZER
1787 def_bool y
1788 prompt "MTRR cleanup support"
1789 depends on MTRR
1790 ---help---
1791 Convert MTRR layout from continuous to discrete, so X drivers can
1792 add writeback entries.
1794 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1795 The largest mtrr entry size for a continuous block can be set with
1796 mtrr_chunk_size.
1798 If unsure, say Y.
1800 config MTRR_SANITIZER_ENABLE_DEFAULT
1801 int "MTRR cleanup enable value (0-1)"
1802 range 0 1
1803 default "0"
1804 depends on MTRR_SANITIZER
1805 ---help---
1806 Enable mtrr cleanup default value
1808 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1809 int "MTRR cleanup spare reg num (0-7)"
1810 range 0 7
1811 default "1"
1812 depends on MTRR_SANITIZER
1813 ---help---
1814 mtrr cleanup spare entries default, it can be changed via
1815 mtrr_spare_reg_nr=N on the kernel command line.
1817 config X86_PAT
1818 def_bool y
1819 prompt "x86 PAT support" if EXPERT
1820 depends on MTRR
1821 ---help---
1822 Use PAT attributes to setup page level cache control.
1824 PATs are the modern equivalents of MTRRs and are much more
1825 flexible than MTRRs.
1827 Say N here if you see bootup problems (boot crash, boot hang,
1828 spontaneous reboots) or a non-working video driver.
1830 If unsure, say Y.
1832 config ARCH_USES_PG_UNCACHED
1833 def_bool y
1834 depends on X86_PAT
1836 config ARCH_RANDOM
1837 def_bool y
1838 prompt "x86 architectural random number generator" if EXPERT
1839 ---help---
1840 Enable the x86 architectural RDRAND instruction
1841 (Intel Bull Mountain technology) to generate random numbers.
1842 If supported, this is a high bandwidth, cryptographically
1843 secure hardware random number generator.
1845 config X86_SMAP
1846 def_bool y
1847 prompt "Supervisor Mode Access Prevention" if EXPERT
1848 ---help---
1849 Supervisor Mode Access Prevention (SMAP) is a security
1850 feature in newer Intel processors. There is a small
1851 performance cost if this enabled and turned on; there is
1852 also a small increase in the kernel size if this is enabled.
1854 If unsure, say Y.
1856 config X86_INTEL_UMIP
1857 def_bool y
1858 depends on CPU_SUP_INTEL
1859 prompt "Intel User Mode Instruction Prevention" if EXPERT
1860 ---help---
1861 The User Mode Instruction Prevention (UMIP) is a security
1862 feature in newer Intel processors. If enabled, a general
1863 protection fault is issued if the SGDT, SLDT, SIDT, SMSW
1864 or STR instructions are executed in user mode. These instructions
1865 unnecessarily expose information about the hardware state.
1867 The vast majority of applications do not use these instructions.
1868 For the very few that do, software emulation is provided in
1869 specific cases in protected and virtual-8086 modes. Emulated
1870 results are dummy.
1872 config X86_INTEL_MPX
1873 prompt "Intel MPX (Memory Protection Extensions)"
1874 def_bool n
1875 # Note: only available in 64-bit mode due to VMA flags shortage
1876 depends on CPU_SUP_INTEL && X86_64
1877 select ARCH_USES_HIGH_VMA_FLAGS
1878 ---help---
1879 MPX provides hardware features that can be used in
1880 conjunction with compiler-instrumented code to check
1881 memory references. It is designed to detect buffer
1882 overflow or underflow bugs.
1884 This option enables running applications which are
1885 instrumented or otherwise use MPX. It does not use MPX
1886 itself inside the kernel or to protect the kernel
1887 against bad memory references.
1889 Enabling this option will make the kernel larger:
1890 ~8k of kernel text and 36 bytes of data on a 64-bit
1891 defconfig. It adds a long to the 'mm_struct' which
1892 will increase the kernel memory overhead of each
1893 process and adds some branches to paths used during
1894 exec() and munmap().
1896 For details, see Documentation/x86/intel_mpx.txt
1898 If unsure, say N.
1900 config X86_INTEL_MEMORY_PROTECTION_KEYS
1901 prompt "Intel Memory Protection Keys"
1902 def_bool y
1903 # Note: only available in 64-bit mode
1904 depends on CPU_SUP_INTEL && X86_64
1905 select ARCH_USES_HIGH_VMA_FLAGS
1906 select ARCH_HAS_PKEYS
1907 ---help---
1908 Memory Protection Keys provides a mechanism for enforcing
1909 page-based protections, but without requiring modification of the
1910 page tables when an application changes protection domains.
1912 For details, see Documentation/x86/protection-keys.txt
1914 If unsure, say y.
1916 config EFI
1917 bool "EFI runtime service support"
1918 depends on ACPI
1919 select UCS2_STRING
1920 select EFI_RUNTIME_WRAPPERS
1921 ---help---
1922 This enables the kernel to use EFI runtime services that are
1923 available (such as the EFI variable services).
1925 This option is only useful on systems that have EFI firmware.
1926 In addition, you should use the latest ELILO loader available
1927 at <http://elilo.sourceforge.net> in order to take advantage
1928 of EFI runtime services. However, even with this option, the
1929 resultant kernel should continue to boot on existing non-EFI
1930 platforms.
1932 config EFI_STUB
1933 bool "EFI stub support"
1934 depends on EFI && !X86_USE_3DNOW
1935 select RELOCATABLE
1936 ---help---
1937 This kernel feature allows a bzImage to be loaded directly
1938 by EFI firmware without the use of a bootloader.
1940 See Documentation/efi-stub.txt for more information.
1942 config EFI_MIXED
1943 bool "EFI mixed-mode support"
1944 depends on EFI_STUB && X86_64
1945 ---help---
1946 Enabling this feature allows a 64-bit kernel to be booted
1947 on a 32-bit firmware, provided that your CPU supports 64-bit
1948 mode.
1950 Note that it is not possible to boot a mixed-mode enabled
1951 kernel via the EFI boot stub - a bootloader that supports
1952 the EFI handover protocol must be used.
1954 If unsure, say N.
1956 config SECCOMP
1957 def_bool y
1958 prompt "Enable seccomp to safely compute untrusted bytecode"
1959 ---help---
1960 This kernel feature is useful for number crunching applications
1961 that may need to compute untrusted bytecode during their
1962 execution. By using pipes or other transports made available to
1963 the process as file descriptors supporting the read/write
1964 syscalls, it's possible to isolate those applications in
1965 their own address space using seccomp. Once seccomp is
1966 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1967 and the task is only allowed to execute a few safe syscalls
1968 defined by each seccomp mode.
1970 If unsure, say Y. Only embedded should say N here.
1972 source kernel/Kconfig.hz
1974 config KEXEC
1975 bool "kexec system call"
1976 select KEXEC_CORE
1977 ---help---
1978 kexec is a system call that implements the ability to shutdown your
1979 current kernel, and to start another kernel. It is like a reboot
1980 but it is independent of the system firmware. And like a reboot
1981 you can start any kernel with it, not just Linux.
1983 The name comes from the similarity to the exec system call.
1985 It is an ongoing process to be certain the hardware in a machine
1986 is properly shutdown, so do not be surprised if this code does not
1987 initially work for you. As of this writing the exact hardware
1988 interface is strongly in flux, so no good recommendation can be
1989 made.
1991 config KEXEC_FILE
1992 bool "kexec file based system call"
1993 select KEXEC_CORE
1994 select BUILD_BIN2C
1995 depends on X86_64
1996 depends on CRYPTO=y
1997 depends on CRYPTO_SHA256=y
1998 ---help---
1999 This is new version of kexec system call. This system call is
2000 file based and takes file descriptors as system call argument
2001 for kernel and initramfs as opposed to list of segments as
2002 accepted by previous system call.
2004 config ARCH_HAS_KEXEC_PURGATORY
2005 def_bool KEXEC_FILE
2007 config KEXEC_VERIFY_SIG
2008 bool "Verify kernel signature during kexec_file_load() syscall"
2009 depends on KEXEC_FILE
2010 ---help---
2011 This option makes kernel signature verification mandatory for
2012 the kexec_file_load() syscall.
2014 In addition to that option, you need to enable signature
2015 verification for the corresponding kernel image type being
2016 loaded in order for this to work.
2018 config KEXEC_BZIMAGE_VERIFY_SIG
2019 bool "Enable bzImage signature verification support"
2020 depends on KEXEC_VERIFY_SIG
2021 depends on SIGNED_PE_FILE_VERIFICATION
2022 select SYSTEM_TRUSTED_KEYRING
2023 ---help---
2024 Enable bzImage signature verification support.
2026 config CRASH_DUMP
2027 bool "kernel crash dumps"
2028 depends on X86_64 || (X86_32 && HIGHMEM)
2029 ---help---
2030 Generate crash dump after being started by kexec.
2031 This should be normally only set in special crash dump kernels
2032 which are loaded in the main kernel with kexec-tools into
2033 a specially reserved region and then later executed after
2034 a crash by kdump/kexec. The crash dump kernel must be compiled
2035 to a memory address not used by the main kernel or BIOS using
2036 PHYSICAL_START, or it must be built as a relocatable image
2037 (CONFIG_RELOCATABLE=y).
2038 For more details see Documentation/kdump/kdump.txt
2040 config KEXEC_JUMP
2041 bool "kexec jump"
2042 depends on KEXEC && HIBERNATION
2043 ---help---
2044 Jump between original kernel and kexeced kernel and invoke
2045 code in physical address mode via KEXEC
2047 config PHYSICAL_START
2048 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2049 default "0x1000000"
2050 ---help---
2051 This gives the physical address where the kernel is loaded.
2053 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2054 bzImage will decompress itself to above physical address and
2055 run from there. Otherwise, bzImage will run from the address where
2056 it has been loaded by the boot loader and will ignore above physical
2057 address.
2059 In normal kdump cases one does not have to set/change this option
2060 as now bzImage can be compiled as a completely relocatable image
2061 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2062 address. This option is mainly useful for the folks who don't want
2063 to use a bzImage for capturing the crash dump and want to use a
2064 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2065 to be specifically compiled to run from a specific memory area
2066 (normally a reserved region) and this option comes handy.
2068 So if you are using bzImage for capturing the crash dump,
2069 leave the value here unchanged to 0x1000000 and set
2070 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2071 for capturing the crash dump change this value to start of
2072 the reserved region. In other words, it can be set based on
2073 the "X" value as specified in the "crashkernel=YM@XM"
2074 command line boot parameter passed to the panic-ed
2075 kernel. Please take a look at Documentation/kdump/kdump.txt
2076 for more details about crash dumps.
2078 Usage of bzImage for capturing the crash dump is recommended as
2079 one does not have to build two kernels. Same kernel can be used
2080 as production kernel and capture kernel. Above option should have
2081 gone away after relocatable bzImage support is introduced. But it
2082 is present because there are users out there who continue to use
2083 vmlinux for dump capture. This option should go away down the
2084 line.
2086 Don't change this unless you know what you are doing.
2088 config RELOCATABLE
2089 bool "Build a relocatable kernel"
2090 default y
2091 ---help---
2092 This builds a kernel image that retains relocation information
2093 so it can be loaded someplace besides the default 1MB.
2094 The relocations tend to make the kernel binary about 10% larger,
2095 but are discarded at runtime.
2097 One use is for the kexec on panic case where the recovery kernel
2098 must live at a different physical address than the primary
2099 kernel.
2101 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2102 it has been loaded at and the compile time physical address
2103 (CONFIG_PHYSICAL_START) is used as the minimum location.
2105 config RANDOMIZE_BASE
2106 bool "Randomize the address of the kernel image (KASLR)"
2107 depends on RELOCATABLE
2108 default y
2109 ---help---
2110 In support of Kernel Address Space Layout Randomization (KASLR),
2111 this randomizes the physical address at which the kernel image
2112 is decompressed and the virtual address where the kernel
2113 image is mapped, as a security feature that deters exploit
2114 attempts relying on knowledge of the location of kernel
2115 code internals.
2117 On 64-bit, the kernel physical and virtual addresses are
2118 randomized separately. The physical address will be anywhere
2119 between 16MB and the top of physical memory (up to 64TB). The
2120 virtual address will be randomized from 16MB up to 1GB (9 bits
2121 of entropy). Note that this also reduces the memory space
2122 available to kernel modules from 1.5GB to 1GB.
2124 On 32-bit, the kernel physical and virtual addresses are
2125 randomized together. They will be randomized from 16MB up to
2126 512MB (8 bits of entropy).
2128 Entropy is generated using the RDRAND instruction if it is
2129 supported. If RDTSC is supported, its value is mixed into
2130 the entropy pool as well. If neither RDRAND nor RDTSC are
2131 supported, then entropy is read from the i8254 timer. The
2132 usable entropy is limited by the kernel being built using
2133 2GB addressing, and that PHYSICAL_ALIGN must be at a
2134 minimum of 2MB. As a result, only 10 bits of entropy are
2135 theoretically possible, but the implementations are further
2136 limited due to memory layouts.
2138 If unsure, say Y.
2140 # Relocation on x86 needs some additional build support
2141 config X86_NEED_RELOCS
2142 def_bool y
2143 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2145 config PHYSICAL_ALIGN
2146 hex "Alignment value to which kernel should be aligned"
2147 default "0x200000"
2148 range 0x2000 0x1000000 if X86_32
2149 range 0x200000 0x1000000 if X86_64
2150 ---help---
2151 This value puts the alignment restrictions on physical address
2152 where kernel is loaded and run from. Kernel is compiled for an
2153 address which meets above alignment restriction.
2155 If bootloader loads the kernel at a non-aligned address and
2156 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2157 address aligned to above value and run from there.
2159 If bootloader loads the kernel at a non-aligned address and
2160 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2161 load address and decompress itself to the address it has been
2162 compiled for and run from there. The address for which kernel is
2163 compiled already meets above alignment restrictions. Hence the
2164 end result is that kernel runs from a physical address meeting
2165 above alignment restrictions.
2167 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2168 this value must be a multiple of 0x200000.
2170 Don't change this unless you know what you are doing.
2172 config DYNAMIC_MEMORY_LAYOUT
2173 bool
2174 ---help---
2175 This option makes base addresses of vmalloc and vmemmap as well as
2176 __PAGE_OFFSET movable during boot.
2178 config RANDOMIZE_MEMORY
2179 bool "Randomize the kernel memory sections"
2180 depends on X86_64
2181 depends on RANDOMIZE_BASE
2182 select DYNAMIC_MEMORY_LAYOUT
2183 default RANDOMIZE_BASE
2184 ---help---
2185 Randomizes the base virtual address of kernel memory sections
2186 (physical memory mapping, vmalloc & vmemmap). This security feature
2187 makes exploits relying on predictable memory locations less reliable.
2189 The order of allocations remains unchanged. Entropy is generated in
2190 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2191 configuration have in average 30,000 different possible virtual
2192 addresses for each memory section.
2194 If unsure, say Y.
2196 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2197 hex "Physical memory mapping padding" if EXPERT
2198 depends on RANDOMIZE_MEMORY
2199 default "0xa" if MEMORY_HOTPLUG
2200 default "0x0"
2201 range 0x1 0x40 if MEMORY_HOTPLUG
2202 range 0x0 0x40
2203 ---help---
2204 Define the padding in terabytes added to the existing physical
2205 memory size during kernel memory randomization. It is useful
2206 for memory hotplug support but reduces the entropy available for
2207 address randomization.
2209 If unsure, leave at the default value.
2211 config HOTPLUG_CPU
2212 bool "Support for hot-pluggable CPUs"
2213 depends on SMP
2214 ---help---
2215 Say Y here to allow turning CPUs off and on. CPUs can be
2216 controlled through /sys/devices/system/cpu.
2217 ( Note: power management support will enable this option
2218 automatically on SMP systems. )
2219 Say N if you want to disable CPU hotplug.
2221 config BOOTPARAM_HOTPLUG_CPU0
2222 bool "Set default setting of cpu0_hotpluggable"
2223 default n
2224 depends on HOTPLUG_CPU
2225 ---help---
2226 Set whether default state of cpu0_hotpluggable is on or off.
2228 Say Y here to enable CPU0 hotplug by default. If this switch
2229 is turned on, there is no need to give cpu0_hotplug kernel
2230 parameter and the CPU0 hotplug feature is enabled by default.
2232 Please note: there are two known CPU0 dependencies if you want
2233 to enable the CPU0 hotplug feature either by this switch or by
2234 cpu0_hotplug kernel parameter.
2236 First, resume from hibernate or suspend always starts from CPU0.
2237 So hibernate and suspend are prevented if CPU0 is offline.
2239 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2240 offline if any interrupt can not migrate out of CPU0. There may
2241 be other CPU0 dependencies.
2243 Please make sure the dependencies are under your control before
2244 you enable this feature.
2246 Say N if you don't want to enable CPU0 hotplug feature by default.
2247 You still can enable the CPU0 hotplug feature at boot by kernel
2248 parameter cpu0_hotplug.
2250 config DEBUG_HOTPLUG_CPU0
2251 def_bool n
2252 prompt "Debug CPU0 hotplug"
2253 depends on HOTPLUG_CPU
2254 ---help---
2255 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2256 soon as possible and boots up userspace with CPU0 offlined. User
2257 can online CPU0 back after boot time.
2259 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2260 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2261 compilation or giving cpu0_hotplug kernel parameter at boot.
2263 If unsure, say N.
2265 config COMPAT_VDSO
2266 def_bool n
2267 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2268 depends on COMPAT_32
2269 ---help---
2270 Certain buggy versions of glibc will crash if they are
2271 presented with a 32-bit vDSO that is not mapped at the address
2272 indicated in its segment table.
2274 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2275 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2276 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2277 the only released version with the bug, but OpenSUSE 9
2278 contains a buggy "glibc 2.3.2".
2280 The symptom of the bug is that everything crashes on startup, saying:
2281 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2283 Saying Y here changes the default value of the vdso32 boot
2284 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2285 This works around the glibc bug but hurts performance.
2287 If unsure, say N: if you are compiling your own kernel, you
2288 are unlikely to be using a buggy version of glibc.
2290 choice
2291 prompt "vsyscall table for legacy applications"
2292 depends on X86_64
2293 default LEGACY_VSYSCALL_EMULATE
2294 help
2295 Legacy user code that does not know how to find the vDSO expects
2296 to be able to issue three syscalls by calling fixed addresses in
2297 kernel space. Since this location is not randomized with ASLR,
2298 it can be used to assist security vulnerability exploitation.
2300 This setting can be changed at boot time via the kernel command
2301 line parameter vsyscall=[emulate|none].
2303 On a system with recent enough glibc (2.14 or newer) and no
2304 static binaries, you can say None without a performance penalty
2305 to improve security.
2307 If unsure, select "Emulate".
2309 config LEGACY_VSYSCALL_EMULATE
2310 bool "Emulate"
2311 help
2312 The kernel traps and emulates calls into the fixed
2313 vsyscall address mapping. This makes the mapping
2314 non-executable, but it still contains known contents,
2315 which could be used in certain rare security vulnerability
2316 exploits. This configuration is recommended when userspace
2317 still uses the vsyscall area.
2319 config LEGACY_VSYSCALL_NONE
2320 bool "None"
2321 help
2322 There will be no vsyscall mapping at all. This will
2323 eliminate any risk of ASLR bypass due to the vsyscall
2324 fixed address mapping. Attempts to use the vsyscalls
2325 will be reported to dmesg, so that either old or
2326 malicious userspace programs can be identified.
2328 endchoice
2330 config CMDLINE_BOOL
2331 bool "Built-in kernel command line"
2332 ---help---
2333 Allow for specifying boot arguments to the kernel at
2334 build time. On some systems (e.g. embedded ones), it is
2335 necessary or convenient to provide some or all of the
2336 kernel boot arguments with the kernel itself (that is,
2337 to not rely on the boot loader to provide them.)
2339 To compile command line arguments into the kernel,
2340 set this option to 'Y', then fill in the
2341 boot arguments in CONFIG_CMDLINE.
2343 Systems with fully functional boot loaders (i.e. non-embedded)
2344 should leave this option set to 'N'.
2346 config CMDLINE
2347 string "Built-in kernel command string"
2348 depends on CMDLINE_BOOL
2349 default ""
2350 ---help---
2351 Enter arguments here that should be compiled into the kernel
2352 image and used at boot time. If the boot loader provides a
2353 command line at boot time, it is appended to this string to
2354 form the full kernel command line, when the system boots.
2356 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2357 change this behavior.
2359 In most cases, the command line (whether built-in or provided
2360 by the boot loader) should specify the device for the root
2361 file system.
2363 config CMDLINE_OVERRIDE
2364 bool "Built-in command line overrides boot loader arguments"
2365 depends on CMDLINE_BOOL
2366 ---help---
2367 Set this option to 'Y' to have the kernel ignore the boot loader
2368 command line, and use ONLY the built-in command line.
2370 This is used to work around broken boot loaders. This should
2371 be set to 'N' under normal conditions.
2373 config MODIFY_LDT_SYSCALL
2374 bool "Enable the LDT (local descriptor table)" if EXPERT
2375 default y
2376 ---help---
2377 Linux can allow user programs to install a per-process x86
2378 Local Descriptor Table (LDT) using the modify_ldt(2) system
2379 call. This is required to run 16-bit or segmented code such as
2380 DOSEMU or some Wine programs. It is also used by some very old
2381 threading libraries.
2383 Enabling this feature adds a small amount of overhead to
2384 context switches and increases the low-level kernel attack
2385 surface. Disabling it removes the modify_ldt(2) system call.
2387 Saying 'N' here may make sense for embedded or server kernels.
2389 source "kernel/livepatch/Kconfig"
2391 endmenu
2393 config ARCH_HAS_ADD_PAGES
2394 def_bool y
2395 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2397 config ARCH_ENABLE_MEMORY_HOTPLUG
2398 def_bool y
2399 depends on X86_64 || (X86_32 && HIGHMEM)
2401 config ARCH_ENABLE_MEMORY_HOTREMOVE
2402 def_bool y
2403 depends on MEMORY_HOTPLUG
2405 config USE_PERCPU_NUMA_NODE_ID
2406 def_bool y
2407 depends on NUMA
2409 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2410 def_bool y
2411 depends on X86_64 || X86_PAE
2413 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2414 def_bool y
2415 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2417 config ARCH_ENABLE_THP_MIGRATION
2418 def_bool y
2419 depends on X86_64 && TRANSPARENT_HUGEPAGE
2421 menu "Power management and ACPI options"
2423 config ARCH_HIBERNATION_HEADER
2424 def_bool y
2425 depends on X86_64 && HIBERNATION
2427 source "kernel/power/Kconfig"
2429 source "drivers/acpi/Kconfig"
2431 source "drivers/sfi/Kconfig"
2433 config X86_APM_BOOT
2434 def_bool y
2435 depends on APM
2437 menuconfig APM
2438 tristate "APM (Advanced Power Management) BIOS support"
2439 depends on X86_32 && PM_SLEEP
2440 ---help---
2441 APM is a BIOS specification for saving power using several different
2442 techniques. This is mostly useful for battery powered laptops with
2443 APM compliant BIOSes. If you say Y here, the system time will be
2444 reset after a RESUME operation, the /proc/apm device will provide
2445 battery status information, and user-space programs will receive
2446 notification of APM "events" (e.g. battery status change).
2448 If you select "Y" here, you can disable actual use of the APM
2449 BIOS by passing the "apm=off" option to the kernel at boot time.
2451 Note that the APM support is almost completely disabled for
2452 machines with more than one CPU.
2454 In order to use APM, you will need supporting software. For location
2455 and more information, read <file:Documentation/power/apm-acpi.txt>
2456 and the Battery Powered Linux mini-HOWTO, available from
2457 <http://www.tldp.org/docs.html#howto>.
2459 This driver does not spin down disk drives (see the hdparm(8)
2460 manpage ("man 8 hdparm") for that), and it doesn't turn off
2461 VESA-compliant "green" monitors.
2463 This driver does not support the TI 4000M TravelMate and the ACER
2464 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2465 desktop machines also don't have compliant BIOSes, and this driver
2466 may cause those machines to panic during the boot phase.
2468 Generally, if you don't have a battery in your machine, there isn't
2469 much point in using this driver and you should say N. If you get
2470 random kernel OOPSes or reboots that don't seem to be related to
2471 anything, try disabling/enabling this option (or disabling/enabling
2472 APM in your BIOS).
2474 Some other things you should try when experiencing seemingly random,
2475 "weird" problems:
2477 1) make sure that you have enough swap space and that it is
2478 enabled.
2479 2) pass the "no-hlt" option to the kernel
2480 3) switch on floating point emulation in the kernel and pass
2481 the "no387" option to the kernel
2482 4) pass the "floppy=nodma" option to the kernel
2483 5) pass the "mem=4M" option to the kernel (thereby disabling
2484 all but the first 4 MB of RAM)
2485 6) make sure that the CPU is not over clocked.
2486 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2487 8) disable the cache from your BIOS settings
2488 9) install a fan for the video card or exchange video RAM
2489 10) install a better fan for the CPU
2490 11) exchange RAM chips
2491 12) exchange the motherboard.
2493 To compile this driver as a module, choose M here: the
2494 module will be called apm.
2496 if APM
2498 config APM_IGNORE_USER_SUSPEND
2499 bool "Ignore USER SUSPEND"
2500 ---help---
2501 This option will ignore USER SUSPEND requests. On machines with a
2502 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2503 series notebooks, it is necessary to say Y because of a BIOS bug.
2505 config APM_DO_ENABLE
2506 bool "Enable PM at boot time"
2507 ---help---
2508 Enable APM features at boot time. From page 36 of the APM BIOS
2509 specification: "When disabled, the APM BIOS does not automatically
2510 power manage devices, enter the Standby State, enter the Suspend
2511 State, or take power saving steps in response to CPU Idle calls."
2512 This driver will make CPU Idle calls when Linux is idle (unless this
2513 feature is turned off -- see "Do CPU IDLE calls", below). This
2514 should always save battery power, but more complicated APM features
2515 will be dependent on your BIOS implementation. You may need to turn
2516 this option off if your computer hangs at boot time when using APM
2517 support, or if it beeps continuously instead of suspending. Turn
2518 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2519 T400CDT. This is off by default since most machines do fine without
2520 this feature.
2522 config APM_CPU_IDLE
2523 depends on CPU_IDLE
2524 bool "Make CPU Idle calls when idle"
2525 ---help---
2526 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2527 On some machines, this can activate improved power savings, such as
2528 a slowed CPU clock rate, when the machine is idle. These idle calls
2529 are made after the idle loop has run for some length of time (e.g.,
2530 333 mS). On some machines, this will cause a hang at boot time or
2531 whenever the CPU becomes idle. (On machines with more than one CPU,
2532 this option does nothing.)
2534 config APM_DISPLAY_BLANK
2535 bool "Enable console blanking using APM"
2536 ---help---
2537 Enable console blanking using the APM. Some laptops can use this to
2538 turn off the LCD backlight when the screen blanker of the Linux
2539 virtual console blanks the screen. Note that this is only used by
2540 the virtual console screen blanker, and won't turn off the backlight
2541 when using the X Window system. This also doesn't have anything to
2542 do with your VESA-compliant power-saving monitor. Further, this
2543 option doesn't work for all laptops -- it might not turn off your
2544 backlight at all, or it might print a lot of errors to the console,
2545 especially if you are using gpm.
2547 config APM_ALLOW_INTS
2548 bool "Allow interrupts during APM BIOS calls"
2549 ---help---
2550 Normally we disable external interrupts while we are making calls to
2551 the APM BIOS as a measure to lessen the effects of a badly behaving
2552 BIOS implementation. The BIOS should reenable interrupts if it
2553 needs to. Unfortunately, some BIOSes do not -- especially those in
2554 many of the newer IBM Thinkpads. If you experience hangs when you
2555 suspend, try setting this to Y. Otherwise, say N.
2557 endif # APM
2559 source "drivers/cpufreq/Kconfig"
2561 source "drivers/cpuidle/Kconfig"
2563 source "drivers/idle/Kconfig"
2565 endmenu
2568 menu "Bus options (PCI etc.)"
2570 config PCI
2571 bool "PCI support"
2572 default y
2573 ---help---
2574 Find out whether you have a PCI motherboard. PCI is the name of a
2575 bus system, i.e. the way the CPU talks to the other stuff inside
2576 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2577 VESA. If you have PCI, say Y, otherwise N.
2579 choice
2580 prompt "PCI access mode"
2581 depends on X86_32 && PCI
2582 default PCI_GOANY
2583 ---help---
2584 On PCI systems, the BIOS can be used to detect the PCI devices and
2585 determine their configuration. However, some old PCI motherboards
2586 have BIOS bugs and may crash if this is done. Also, some embedded
2587 PCI-based systems don't have any BIOS at all. Linux can also try to
2588 detect the PCI hardware directly without using the BIOS.
2590 With this option, you can specify how Linux should detect the
2591 PCI devices. If you choose "BIOS", the BIOS will be used,
2592 if you choose "Direct", the BIOS won't be used, and if you
2593 choose "MMConfig", then PCI Express MMCONFIG will be used.
2594 If you choose "Any", the kernel will try MMCONFIG, then the
2595 direct access method and falls back to the BIOS if that doesn't
2596 work. If unsure, go with the default, which is "Any".
2598 config PCI_GOBIOS
2599 bool "BIOS"
2601 config PCI_GOMMCONFIG
2602 bool "MMConfig"
2604 config PCI_GODIRECT
2605 bool "Direct"
2607 config PCI_GOOLPC
2608 bool "OLPC XO-1"
2609 depends on OLPC
2611 config PCI_GOANY
2612 bool "Any"
2614 endchoice
2616 config PCI_BIOS
2617 def_bool y
2618 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2620 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2621 config PCI_DIRECT
2622 def_bool y
2623 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2625 config PCI_MMCONFIG
2626 bool "Support mmconfig PCI config space access" if X86_64
2627 default y
2628 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2629 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2631 config PCI_OLPC
2632 def_bool y
2633 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2635 config PCI_XEN
2636 def_bool y
2637 depends on PCI && XEN
2638 select SWIOTLB_XEN
2640 config PCI_DOMAINS
2641 def_bool y
2642 depends on PCI
2644 config MMCONF_FAM10H
2645 def_bool y
2646 depends on X86_64 && PCI_MMCONFIG && ACPI
2648 config PCI_CNB20LE_QUIRK
2649 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2650 depends on PCI
2651 help
2652 Read the PCI windows out of the CNB20LE host bridge. This allows
2653 PCI hotplug to work on systems with the CNB20LE chipset which do
2654 not have ACPI.
2656 There's no public spec for this chipset, and this functionality
2657 is known to be incomplete.
2659 You should say N unless you know you need this.
2661 source "drivers/pci/Kconfig"
2663 config ISA_BUS
2664 bool "ISA bus support on modern systems" if EXPERT
2665 help
2666 Expose ISA bus device drivers and options available for selection and
2667 configuration. Enable this option if your target machine has an ISA
2668 bus. ISA is an older system, displaced by PCI and newer bus
2669 architectures -- if your target machine is modern, it probably does
2670 not have an ISA bus.
2672 If unsure, say N.
2674 # x86_64 have no ISA slots, but can have ISA-style DMA.
2675 config ISA_DMA_API
2676 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2677 default y
2678 help
2679 Enables ISA-style DMA support for devices requiring such controllers.
2680 If unsure, say Y.
2682 if X86_32
2684 config ISA
2685 bool "ISA support"
2686 ---help---
2687 Find out whether you have ISA slots on your motherboard. ISA is the
2688 name of a bus system, i.e. the way the CPU talks to the other stuff
2689 inside your box. Other bus systems are PCI, EISA, MicroChannel
2690 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2691 newer boards don't support it. If you have ISA, say Y, otherwise N.
2693 config EISA
2694 bool "EISA support"
2695 depends on ISA
2696 ---help---
2697 The Extended Industry Standard Architecture (EISA) bus was
2698 developed as an open alternative to the IBM MicroChannel bus.
2700 The EISA bus provided some of the features of the IBM MicroChannel
2701 bus while maintaining backward compatibility with cards made for
2702 the older ISA bus. The EISA bus saw limited use between 1988 and
2703 1995 when it was made obsolete by the PCI bus.
2705 Say Y here if you are building a kernel for an EISA-based machine.
2707 Otherwise, say N.
2709 source "drivers/eisa/Kconfig"
2711 config SCx200
2712 tristate "NatSemi SCx200 support"
2713 ---help---
2714 This provides basic support for National Semiconductor's
2715 (now AMD's) Geode processors. The driver probes for the
2716 PCI-IDs of several on-chip devices, so its a good dependency
2717 for other scx200_* drivers.
2719 If compiled as a module, the driver is named scx200.
2721 config SCx200HR_TIMER
2722 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2723 depends on SCx200
2724 default y
2725 ---help---
2726 This driver provides a clocksource built upon the on-chip
2727 27MHz high-resolution timer. Its also a workaround for
2728 NSC Geode SC-1100's buggy TSC, which loses time when the
2729 processor goes idle (as is done by the scheduler). The
2730 other workaround is idle=poll boot option.
2732 config OLPC
2733 bool "One Laptop Per Child support"
2734 depends on !X86_PAE
2735 select GPIOLIB
2736 select OF
2737 select OF_PROMTREE
2738 select IRQ_DOMAIN
2739 ---help---
2740 Add support for detecting the unique features of the OLPC
2741 XO hardware.
2743 config OLPC_XO1_PM
2744 bool "OLPC XO-1 Power Management"
2745 depends on OLPC && MFD_CS5535 && PM_SLEEP
2746 select MFD_CORE
2747 ---help---
2748 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2750 config OLPC_XO1_RTC
2751 bool "OLPC XO-1 Real Time Clock"
2752 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2753 ---help---
2754 Add support for the XO-1 real time clock, which can be used as a
2755 programmable wakeup source.
2757 config OLPC_XO1_SCI
2758 bool "OLPC XO-1 SCI extras"
2759 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2760 depends on INPUT=y
2761 select POWER_SUPPLY
2762 ---help---
2763 Add support for SCI-based features of the OLPC XO-1 laptop:
2764 - EC-driven system wakeups
2765 - Power button
2766 - Ebook switch
2767 - Lid switch
2768 - AC adapter status updates
2769 - Battery status updates
2771 config OLPC_XO15_SCI
2772 bool "OLPC XO-1.5 SCI extras"
2773 depends on OLPC && ACPI
2774 select POWER_SUPPLY
2775 ---help---
2776 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2777 - EC-driven system wakeups
2778 - AC adapter status updates
2779 - Battery status updates
2781 config ALIX
2782 bool "PCEngines ALIX System Support (LED setup)"
2783 select GPIOLIB
2784 ---help---
2785 This option enables system support for the PCEngines ALIX.
2786 At present this just sets up LEDs for GPIO control on
2787 ALIX2/3/6 boards. However, other system specific setup should
2788 get added here.
2790 Note: You must still enable the drivers for GPIO and LED support
2791 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2793 Note: You have to set alix.force=1 for boards with Award BIOS.
2795 config NET5501
2796 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2797 select GPIOLIB
2798 ---help---
2799 This option enables system support for the Soekris Engineering net5501.
2801 config GEOS
2802 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2803 select GPIOLIB
2804 depends on DMI
2805 ---help---
2806 This option enables system support for the Traverse Technologies GEOS.
2808 config TS5500
2809 bool "Technologic Systems TS-5500 platform support"
2810 depends on MELAN
2811 select CHECK_SIGNATURE
2812 select NEW_LEDS
2813 select LEDS_CLASS
2814 ---help---
2815 This option enables system support for the Technologic Systems TS-5500.
2817 endif # X86_32
2819 config AMD_NB
2820 def_bool y
2821 depends on CPU_SUP_AMD && PCI
2823 source "drivers/pcmcia/Kconfig"
2825 config RAPIDIO
2826 tristate "RapidIO support"
2827 depends on PCI
2828 default n
2829 help
2830 If enabled this option will include drivers and the core
2831 infrastructure code to support RapidIO interconnect devices.
2833 source "drivers/rapidio/Kconfig"
2835 config X86_SYSFB
2836 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2837 help
2838 Firmwares often provide initial graphics framebuffers so the BIOS,
2839 bootloader or kernel can show basic video-output during boot for
2840 user-guidance and debugging. Historically, x86 used the VESA BIOS
2841 Extensions and EFI-framebuffers for this, which are mostly limited
2842 to x86.
2843 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2844 framebuffers so the new generic system-framebuffer drivers can be
2845 used on x86. If the framebuffer is not compatible with the generic
2846 modes, it is advertised as fallback platform framebuffer so legacy
2847 drivers like efifb, vesafb and uvesafb can pick it up.
2848 If this option is not selected, all system framebuffers are always
2849 marked as fallback platform framebuffers as usual.
2851 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2852 not be able to pick up generic system framebuffers if this option
2853 is selected. You are highly encouraged to enable simplefb as
2854 replacement if you select this option. simplefb can correctly deal
2855 with generic system framebuffers. But you should still keep vesafb
2856 and others enabled as fallback if a system framebuffer is
2857 incompatible with simplefb.
2859 If unsure, say Y.
2861 endmenu
2864 menu "Binary Emulations"
2866 config IA32_EMULATION
2867 bool "IA32 Emulation"
2868 depends on X86_64
2869 select ARCH_WANT_OLD_COMPAT_IPC
2870 select BINFMT_ELF
2871 select COMPAT_BINFMT_ELF
2872 select COMPAT_OLD_SIGACTION
2873 ---help---
2874 Include code to run legacy 32-bit programs under a
2875 64-bit kernel. You should likely turn this on, unless you're
2876 100% sure that you don't have any 32-bit programs left.
2878 config IA32_AOUT
2879 tristate "IA32 a.out support"
2880 depends on IA32_EMULATION
2881 ---help---
2882 Support old a.out binaries in the 32bit emulation.
2884 config X86_X32
2885 bool "x32 ABI for 64-bit mode"
2886 depends on X86_64
2887 ---help---
2888 Include code to run binaries for the x32 native 32-bit ABI
2889 for 64-bit processors. An x32 process gets access to the
2890 full 64-bit register file and wide data path while leaving
2891 pointers at 32 bits for smaller memory footprint.
2893 You will need a recent binutils (2.22 or later) with
2894 elf32_x86_64 support enabled to compile a kernel with this
2895 option set.
2897 config COMPAT_32
2898 def_bool y
2899 depends on IA32_EMULATION || X86_32
2900 select HAVE_UID16
2901 select OLD_SIGSUSPEND3
2903 config COMPAT
2904 def_bool y
2905 depends on IA32_EMULATION || X86_X32
2907 if COMPAT
2908 config COMPAT_FOR_U64_ALIGNMENT
2909 def_bool y
2911 config SYSVIPC_COMPAT
2912 def_bool y
2913 depends on SYSVIPC
2914 endif
2916 endmenu
2919 config HAVE_ATOMIC_IOMAP
2920 def_bool y
2921 depends on X86_32
2923 config X86_DEV_DMA_OPS
2924 bool
2925 depends on X86_64 || STA2X11
2927 config X86_DMA_REMAP
2928 bool
2929 depends on STA2X11
2931 config HAVE_GENERIC_GUP
2932 def_bool y
2934 source "drivers/firmware/Kconfig"
2936 source "arch/x86/kvm/Kconfig"