1
2
3config 64BIT
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
6 ---help---
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11 def_bool y
12 depends on !64BIT
13
14 select ARCH_WANT_IPC_PARSE_VERSION
15 select CLKSRC_I8253
16 select CLONE_BACKWARDS
17 select HAVE_DEBUG_STACKOVERFLOW
18 select MODULES_USE_ELF_REL
19 select OLD_SIGACTION
20 select GENERIC_VDSO_32
21
22config X86_64
23 def_bool y
24 depends on 64BIT
25
26 select ARCH_HAS_GIGANTIC_PAGE
27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
28 select ARCH_USE_CMPXCHG_LOCKREF
29 select HAVE_ARCH_SOFT_DIRTY
30 select MODULES_USE_ELF_RELA
31 select NEED_DMA_MAP_STATE
32 select SWIOTLB
33 select ARCH_HAS_SYSCALL_WRAPPER
34
35config FORCE_DYNAMIC_FTRACE
36 def_bool y
37 depends on X86_32
38 depends on FUNCTION_TRACER
39 select DYNAMIC_FTRACE
40 help
41 We keep the static function tracing (!DYNAMIC_FTRACE) around
42 in order to test the non static function tracing in the
43 generic code, as other architectures still use it. But we
44 only need to keep it around for x86_64. No need to keep it
45 for x86_32. For x86_32, force DYNAMIC_FTRACE.
46
47
48
49
50
51
52config X86
53 def_bool y
54
55
56
57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
59 select ARCH_32BIT_OFF_T if X86_32
60 select ARCH_CLOCKSOURCE_DATA
61 select ARCH_CLOCKSOURCE_INIT
62 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
63 select ARCH_HAS_DEBUG_VIRTUAL
64 select ARCH_HAS_DEVMEM_IS_ALLOWED
65 select ARCH_HAS_ELF_RANDOMIZE
66 select ARCH_HAS_FAST_MULTIPLIER
67 select ARCH_HAS_FILTER_PGPROT
68 select ARCH_HAS_FORTIFY_SOURCE
69 select ARCH_HAS_GCOV_PROFILE_ALL
70 select ARCH_HAS_KCOV if X86_64
71 select ARCH_HAS_MEM_ENCRYPT
72 select ARCH_HAS_MEMBARRIER_SYNC_CORE
73 select ARCH_HAS_PMEM_API if X86_64
74 select ARCH_HAS_PTE_DEVMAP if X86_64
75 select ARCH_HAS_PTE_SPECIAL
76 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
77 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
78 select ARCH_HAS_SET_MEMORY
79 select ARCH_HAS_SET_DIRECT_MAP
80 select ARCH_HAS_STRICT_KERNEL_RWX
81 select ARCH_HAS_STRICT_MODULE_RWX
82 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
83 select ARCH_HAS_UBSAN_SANITIZE_ALL
84 select ARCH_HAVE_NMI_SAFE_CMPXCHG
85 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
86 select ARCH_MIGHT_HAVE_PC_PARPORT
87 select ARCH_MIGHT_HAVE_PC_SERIO
88 select ARCH_STACKWALK
89 select ARCH_SUPPORTS_ACPI
90 select ARCH_SUPPORTS_ATOMIC_RMW
91 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
92 select ARCH_USE_BUILTIN_BSWAP
93 select ARCH_USE_QUEUED_RWLOCKS
94 select ARCH_USE_QUEUED_SPINLOCKS
95 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
96 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
97 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
98 select ARCH_WANT_HUGE_PMD_SHARE
99 select ARCH_WANTS_THP_SWAP if X86_64
100 select BUILDTIME_TABLE_SORT
101 select CLKEVT_I8253
102 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
103 select CLOCKSOURCE_WATCHDOG
104 select DCACHE_WORD_ACCESS
105 select EDAC_ATOMIC_SCRUB
106 select EDAC_SUPPORT
107 select GENERIC_CLOCKEVENTS
108 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
109 select GENERIC_CLOCKEVENTS_MIN_ADJUST
110 select GENERIC_CMOS_UPDATE
111 select GENERIC_CPU_AUTOPROBE
112 select GENERIC_CPU_VULNERABILITIES
113 select GENERIC_EARLY_IOREMAP
114 select GENERIC_FIND_FIRST_BIT
115 select GENERIC_IOMAP
116 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
117 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
118 select GENERIC_IRQ_MIGRATION if SMP
119 select GENERIC_IRQ_PROBE
120 select GENERIC_IRQ_RESERVATION_MODE
121 select GENERIC_IRQ_SHOW
122 select GENERIC_PENDING_IRQ if SMP
123 select GENERIC_PTDUMP
124 select GENERIC_SMP_IDLE_THREAD
125 select GENERIC_STRNCPY_FROM_USER
126 select GENERIC_STRNLEN_USER
127 select GENERIC_TIME_VSYSCALL
128 select GENERIC_GETTIMEOFDAY
129 select GENERIC_VDSO_TIME_NS
130 select GUP_GET_PTE_LOW_HIGH if X86_PAE
131 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
132 select HAVE_ACPI_APEI if ACPI
133 select HAVE_ACPI_APEI_NMI if ACPI
134 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
135 select HAVE_ARCH_AUDITSYSCALL
136 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
137 select HAVE_ARCH_JUMP_LABEL
138 select HAVE_ARCH_JUMP_LABEL_RELATIVE
139 select HAVE_ARCH_KASAN if X86_64
140 select HAVE_ARCH_KASAN_VMALLOC if X86_64
141 select HAVE_ARCH_KGDB
142 select HAVE_ARCH_MMAP_RND_BITS if MMU
143 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
144 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
145 select HAVE_ARCH_PREL32_RELOCATIONS
146 select HAVE_ARCH_SECCOMP_FILTER
147 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
148 select HAVE_ARCH_STACKLEAK
149 select HAVE_ARCH_TRACEHOOK
150 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
151 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
152 select HAVE_ARCH_VMAP_STACK if X86_64
153 select HAVE_ARCH_WITHIN_STACK_FRAMES
154 select HAVE_ASM_MODVERSIONS
155 select HAVE_CMPXCHG_DOUBLE
156 select HAVE_CMPXCHG_LOCAL
157 select HAVE_CONTEXT_TRACKING if X86_64
158 select HAVE_COPY_THREAD_TLS
159 select HAVE_C_RECORDMCOUNT
160 select HAVE_DEBUG_KMEMLEAK
161 select HAVE_DMA_CONTIGUOUS
162 select HAVE_DYNAMIC_FTRACE
163 select HAVE_DYNAMIC_FTRACE_WITH_REGS
164 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
165 select HAVE_EBPF_JIT
166 select HAVE_EFFICIENT_UNALIGNED_ACCESS
167 select HAVE_EISA
168 select HAVE_EXIT_THREAD
169 select HAVE_FAST_GUP
170 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
171 select HAVE_FTRACE_MCOUNT_RECORD
172 select HAVE_FUNCTION_GRAPH_TRACER
173 select HAVE_FUNCTION_TRACER
174 select HAVE_GCC_PLUGINS
175 select HAVE_HW_BREAKPOINT
176 select HAVE_IDE
177 select HAVE_IOREMAP_PROT
178 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
179 select HAVE_IRQ_TIME_ACCOUNTING
180 select HAVE_KERNEL_BZIP2
181 select HAVE_KERNEL_GZIP
182 select HAVE_KERNEL_LZ4
183 select HAVE_KERNEL_LZMA
184 select HAVE_KERNEL_LZO
185 select HAVE_KERNEL_XZ
186 select HAVE_KPROBES
187 select HAVE_KPROBES_ON_FTRACE
188 select HAVE_FUNCTION_ERROR_INJECTION
189 select HAVE_KRETPROBES
190 select HAVE_KVM
191 select HAVE_LIVEPATCH if X86_64
192 select HAVE_MEMBLOCK_NODE_MAP
193 select HAVE_MIXED_BREAKPOINTS_REGS
194 select HAVE_MOD_ARCH_SPECIFIC
195 select HAVE_MOVE_PMD
196 select HAVE_NMI
197 select HAVE_OPROFILE
198 select HAVE_OPTPROBES
199 select HAVE_PCSPKR_PLATFORM
200 select HAVE_PERF_EVENTS
201 select HAVE_PERF_EVENTS_NMI
202 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
203 select HAVE_PCI
204 select HAVE_PERF_REGS
205 select HAVE_PERF_USER_STACK_DUMP
206 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
207 select HAVE_REGS_AND_STACK_ACCESS_API
208 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
209 select HAVE_FUNCTION_ARG_ACCESS_API
210 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
211 select HAVE_STACK_VALIDATION if X86_64
212 select HAVE_RSEQ
213 select HAVE_SYSCALL_TRACEPOINTS
214 select HAVE_UNSTABLE_SCHED_CLOCK
215 select HAVE_USER_RETURN_NOTIFIER
216 select HAVE_GENERIC_VDSO
217 select HOTPLUG_SMT if SMP
218 select IRQ_FORCED_THREADING
219 select NEED_SG_DMA_LENGTH
220 select PCI_DOMAINS if PCI
221 select PCI_LOCKLESS_CONFIG if PCI
222 select PERF_EVENTS
223 select RTC_LIB
224 select RTC_MC146818_LIB
225 select SPARSE_IRQ
226 select SRCU
227 select SYSCTL_EXCEPTION_TRACE
228 select THREAD_INFO_IN_TASK
229 select USER_STACKTRACE_SUPPORT
230 select VIRT_TO_BUS
231 select X86_FEATURE_NAMES if PROC_FS
232 select PROC_PID_ARCH_STATUS if PROC_FS
233
234config INSTRUCTION_DECODER
235 def_bool y
236 depends on KPROBES || PERF_EVENTS || UPROBES
237
238config OUTPUT_FORMAT
239 string
240 default "elf32-i386" if X86_32
241 default "elf64-x86-64" if X86_64
242
243config ARCH_DEFCONFIG
244 string
245 default "arch/x86/configs/i386_defconfig" if X86_32
246 default "arch/x86/configs/x86_64_defconfig" if X86_64
247
248config LOCKDEP_SUPPORT
249 def_bool y
250
251config STACKTRACE_SUPPORT
252 def_bool y
253
254config MMU
255 def_bool y
256
257config ARCH_MMAP_RND_BITS_MIN
258 default 28 if 64BIT
259 default 8
260
261config ARCH_MMAP_RND_BITS_MAX
262 default 32 if 64BIT
263 default 16
264
265config ARCH_MMAP_RND_COMPAT_BITS_MIN
266 default 8
267
268config ARCH_MMAP_RND_COMPAT_BITS_MAX
269 default 16
270
271config SBUS
272 bool
273
274config GENERIC_ISA_DMA
275 def_bool y
276 depends on ISA_DMA_API
277
278config GENERIC_BUG
279 def_bool y
280 depends on BUG
281 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
282
283config GENERIC_BUG_RELATIVE_POINTERS
284 bool
285
286config ARCH_MAY_HAVE_PC_FDC
287 def_bool y
288 depends on ISA_DMA_API
289
290config GENERIC_CALIBRATE_DELAY
291 def_bool y
292
293config ARCH_HAS_CPU_RELAX
294 def_bool y
295
296config ARCH_HAS_CACHE_LINE_SIZE
297 def_bool y
298
299config ARCH_HAS_FILTER_PGPROT
300 def_bool y
301
302config HAVE_SETUP_PER_CPU_AREA
303 def_bool y
304
305config NEED_PER_CPU_EMBED_FIRST_CHUNK
306 def_bool y
307
308config NEED_PER_CPU_PAGE_FIRST_CHUNK
309 def_bool y
310
311config ARCH_HIBERNATION_POSSIBLE
312 def_bool y
313
314config ARCH_SUSPEND_POSSIBLE
315 def_bool y
316
317config ARCH_WANT_GENERAL_HUGETLB
318 def_bool y
319
320config ZONE_DMA32
321 def_bool y if X86_64
322
323config AUDIT_ARCH
324 def_bool y if X86_64
325
326config ARCH_SUPPORTS_DEBUG_PAGEALLOC
327 def_bool y
328
329config KASAN_SHADOW_OFFSET
330 hex
331 depends on KASAN
332 default 0xdffffc0000000000
333
334config HAVE_INTEL_TXT
335 def_bool y
336 depends on INTEL_IOMMU && ACPI
337
338config X86_32_SMP
339 def_bool y
340 depends on X86_32 && SMP
341
342config X86_64_SMP
343 def_bool y
344 depends on X86_64 && SMP
345
346config X86_32_LAZY_GS
347 def_bool y
348 depends on X86_32 && !STACKPROTECTOR
349
350config ARCH_SUPPORTS_UPROBES
351 def_bool y
352
353config FIX_EARLYCON_MEM
354 def_bool y
355
356config DYNAMIC_PHYSICAL_MASK
357 bool
358
359config PGTABLE_LEVELS
360 int
361 default 5 if X86_5LEVEL
362 default 4 if X86_64
363 default 3 if X86_PAE
364 default 2
365
366config CC_HAS_SANE_STACKPROTECTOR
367 bool
368 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
369 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
370 help
371 We have to make sure stack protector is unconditionally disabled if
372 the compiler produces broken code.
373
374menu "Processor type and features"
375
376config ZONE_DMA
377 bool "DMA memory allocation support" if EXPERT
378 default y
379 help
380 DMA memory allocation support allows devices with less than 32-bit
381 addressing to allocate within the first 16MB of address space.
382 Disable if no such devices will be used.
383
384 If unsure, say Y.
385
386config SMP
387 bool "Symmetric multi-processing support"
388 ---help---
389 This enables support for systems with more than one CPU. If you have
390 a system with only one CPU, say N. If you have a system with more
391 than one CPU, say Y.
392
393 If you say N here, the kernel will run on uni- and multiprocessor
394 machines, but will use only one CPU of a multiprocessor machine. If
395 you say Y here, the kernel will run on many, but not all,
396 uniprocessor machines. On a uniprocessor machine, the kernel
397 will run faster if you say N here.
398
399 Note that if you say Y here and choose architecture "586" or
400 "Pentium" under "Processor family", the kernel will not work on 486
401 architectures. Similarly, multiprocessor kernels for the "PPro"
402 architecture may not work on all Pentium based boards.
403
404 People using multiprocessor machines who say Y here should also say
405 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
406 Management" code will be disabled if you say Y here.
407
408 See also <file:Documentation/x86/i386/IO-APIC.rst>,
409 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
410 <http://www.tldp.org/docs.html
411
412 If you don't know what to do here, say N.
413
414config X86_FEATURE_NAMES
415 bool "Processor feature human-readable names" if EMBEDDED
416 default y
417 ---help---
418 This option compiles in a table of x86 feature bits and corresponding
419 names. This is required to support /proc/cpuinfo and a few kernel
420 messages. You can disable this to save space, at the expense of
421 making those few kernel messages show numeric feature bits instead.
422
423 If in doubt, say Y.
424
425config X86_X2APIC
426 bool "Support x2apic"
427 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
428 ---help---
429 This enables x2apic support on CPUs that have this feature.
430
431 This allows 32-bit apic IDs (so it can support very large systems),
432 and accesses the local apic via MSRs not via mmio.
433
434 If you don't know what to do here, say N.
435
436config X86_MPPARSE
437 bool "Enable MPS table" if ACPI || SFI
438 default y
439 depends on X86_LOCAL_APIC
440 ---help---
441 For old smp systems that do not have proper acpi support. Newer systems
442 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
443
444config GOLDFISH
445 def_bool y
446 depends on X86_GOLDFISH
447
448config RETPOLINE
449 bool "Avoid speculative indirect branches in kernel"
450 default y
451 select STACK_VALIDATION if HAVE_STACK_VALIDATION
452 help
453 Compile kernel with the retpoline compiler options to guard against
454 kernel-to-user data leaks by avoiding speculative indirect
455 branches. Requires a compiler with -mindirect-branch=thunk-extern
456 support for full protection. The kernel may run slower.
457
458config X86_CPU_RESCTRL
459 bool "x86 CPU resource control support"
460 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
461 select KERNFS
462 select PROC_CPU_RESCTRL if PROC_FS
463 help
464 Enable x86 CPU resource control support.
465
466 Provide support for the allocation and monitoring of system resources
467 usage by the CPU.
468
469 Intel calls this Intel Resource Director Technology
470 (Intel(R) RDT). More information about RDT can be found in the
471 Intel x86 Architecture Software Developer Manual.
472
473 AMD calls this AMD Platform Quality of Service (AMD QoS).
474 More information about AMD QoS can be found in the AMD64 Technology
475 Platform Quality of Service Extensions manual.
476
477 Say N if unsure.
478
479if X86_32
480config X86_BIGSMP
481 bool "Support for big SMP systems with more than 8 CPUs"
482 depends on SMP
483 ---help---
484 This option is needed for the systems that have more than 8 CPUs.
485
486config X86_EXTENDED_PLATFORM
487 bool "Support for extended (non-PC) x86 platforms"
488 default y
489 ---help---
490 If you disable this option then the kernel will only support
491 standard PC platforms. (which covers the vast majority of
492 systems out there.)
493
494 If you enable this option then you'll be able to select support
495 for the following (non-PC) 32 bit x86 platforms:
496 Goldfish (Android emulator)
497 AMD Elan
498 RDC R-321x SoC
499 SGI 320/540 (Visual Workstation)
500 STA2X11-based (e.g. Northville)
501 Moorestown MID devices
502
503 If you have one of these systems, or if you want to build a
504 generic distribution kernel, say Y here - otherwise say N.
505endif
506
507if X86_64
508config X86_EXTENDED_PLATFORM
509 bool "Support for extended (non-PC) x86 platforms"
510 default y
511 ---help---
512 If you disable this option then the kernel will only support
513 standard PC platforms. (which covers the vast majority of
514 systems out there.)
515
516 If you enable this option then you'll be able to select support
517 for the following (non-PC) 64 bit x86 platforms:
518 Numascale NumaChip
519 ScaleMP vSMP
520 SGI Ultraviolet
521
522 If you have one of these systems, or if you want to build a
523 generic distribution kernel, say Y here - otherwise say N.
524endif
525
526
527config X86_NUMACHIP
528 bool "Numascale NumaChip"
529 depends on X86_64
530 depends on X86_EXTENDED_PLATFORM
531 depends on NUMA
532 depends on SMP
533 depends on X86_X2APIC
534 depends on PCI_MMCONFIG
535 ---help---
536 Adds support for Numascale NumaChip large-SMP systems. Needed to
537 enable more than ~168 cores.
538 If you don't have one of these, you should say N here.
539
540config X86_VSMP
541 bool "ScaleMP vSMP"
542 select HYPERVISOR_GUEST
543 select PARAVIRT
544 depends on X86_64 && PCI
545 depends on X86_EXTENDED_PLATFORM
546 depends on SMP
547 ---help---
548 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
549 supposed to run on these EM64T-based machines. Only choose this option
550 if you have one of these machines.
551
552config X86_UV
553 bool "SGI Ultraviolet"
554 depends on X86_64
555 depends on X86_EXTENDED_PLATFORM
556 depends on NUMA
557 depends on EFI
558 depends on X86_X2APIC
559 depends on PCI
560 ---help---
561 This option is needed in order to support SGI Ultraviolet systems.
562 If you don't have one of these, you should say N here.
563
564
565
566
567config X86_GOLDFISH
568 bool "Goldfish (Virtual Platform)"
569 depends on X86_EXTENDED_PLATFORM
570 ---help---
571 Enable support for the Goldfish virtual platform used primarily
572 for Android development. Unless you are building for the Android
573 Goldfish emulator say N here.
574
575config X86_INTEL_CE
576 bool "CE4100 TV platform"
577 depends on PCI
578 depends on PCI_GODIRECT
579 depends on X86_IO_APIC
580 depends on X86_32
581 depends on X86_EXTENDED_PLATFORM
582 select X86_REBOOTFIXUPS
583 select OF
584 select OF_EARLY_FLATTREE
585 ---help---
586 Select for the Intel CE media processor (CE4100) SOC.
587 This option compiles in support for the CE4100 SOC for settop
588 boxes and media devices.
589
590config X86_INTEL_MID
591 bool "Intel MID platform support"
592 depends on X86_EXTENDED_PLATFORM
593 depends on X86_PLATFORM_DEVICES
594 depends on PCI
595 depends on X86_64 || (PCI_GOANY && X86_32)
596 depends on X86_IO_APIC
597 select SFI
598 select I2C
599 select DW_APB_TIMER
600 select APB_TIMER
601 select INTEL_SCU_IPC
602 select MFD_INTEL_MSIC
603 ---help---
604 Select to build a kernel capable of supporting Intel MID (Mobile
605 Internet Device) platform systems which do not have the PCI legacy
606 interfaces. If you are building for a PC class system say N here.
607
608 Intel MID platforms are based on an Intel processor and chipset which
609 consume less power than most of the x86 derivatives.
610
611config X86_INTEL_QUARK
612 bool "Intel Quark platform support"
613 depends on X86_32
614 depends on X86_EXTENDED_PLATFORM
615 depends on X86_PLATFORM_DEVICES
616 depends on X86_TSC
617 depends on PCI
618 depends on PCI_GOANY
619 depends on X86_IO_APIC
620 select IOSF_MBI
621 select INTEL_IMR
622 select COMMON_CLK
623 ---help---
624 Select to include support for Quark X1000 SoC.
625 Say Y here if you have a Quark based system such as the Arduino
626 compatible Intel Galileo.
627
628config X86_INTEL_LPSS
629 bool "Intel Low Power Subsystem Support"
630 depends on X86 && ACPI && PCI
631 select COMMON_CLK
632 select PINCTRL
633 select IOSF_MBI
634 ---help---
635 Select to build support for Intel Low Power Subsystem such as
636 found on Intel Lynxpoint PCH. Selecting this option enables
637 things like clock tree (common clock framework) and pincontrol
638 which are needed by the LPSS peripheral drivers.
639
640config X86_AMD_PLATFORM_DEVICE
641 bool "AMD ACPI2Platform devices support"
642 depends on ACPI
643 select COMMON_CLK
644 select PINCTRL
645 ---help---
646 Select to interpret AMD specific ACPI device to platform device
647 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
648 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
649 implemented under PINCTRL subsystem.
650
651config IOSF_MBI
652 tristate "Intel SoC IOSF Sideband support for SoC platforms"
653 depends on PCI
654 ---help---
655 This option enables sideband register access support for Intel SoC
656 platforms. On these platforms the IOSF sideband is used in lieu of
657 MSR's for some register accesses, mostly but not limited to thermal
658 and power. Drivers may query the availability of this device to
659 determine if they need the sideband in order to work on these
660 platforms. The sideband is available on the following SoC products.
661 This list is not meant to be exclusive.
662 - BayTrail
663 - Braswell
664 - Quark
665
666 You should say Y if you are running a kernel on one of these SoC's.
667
668config IOSF_MBI_DEBUG
669 bool "Enable IOSF sideband access through debugfs"
670 depends on IOSF_MBI && DEBUG_FS
671 ---help---
672 Select this option to expose the IOSF sideband access registers (MCR,
673 MDR, MCRX) through debugfs to write and read register information from
674 different units on the SoC. This is most useful for obtaining device
675 state information for debug and analysis. As this is a general access
676 mechanism, users of this option would have specific knowledge of the
677 device they want to access.
678
679 If you don't require the option or are in doubt, say N.
680
681config X86_RDC321X
682 bool "RDC R-321x SoC"
683 depends on X86_32
684 depends on X86_EXTENDED_PLATFORM
685 select M486
686 select X86_REBOOTFIXUPS
687 ---help---
688 This option is needed for RDC R-321x system-on-chip, also known
689 as R-8610-(G).
690 If you don't have one of these chips, you should say N here.
691
692config X86_32_NON_STANDARD
693 bool "Support non-standard 32-bit SMP architectures"
694 depends on X86_32 && SMP
695 depends on X86_EXTENDED_PLATFORM
696 ---help---
697 This option compiles in the bigsmp and STA2X11 default
698 subarchitectures. It is intended for a generic binary
699 kernel. If you select them all, kernel will probe it one by
700 one and will fallback to default.
701
702
703
704config X86_SUPPORTS_MEMORY_FAILURE
705 def_bool y
706
707 depends on X86_MCE
708
709
710 depends on X86_64 || !SPARSEMEM
711 select ARCH_SUPPORTS_MEMORY_FAILURE
712
713config STA2X11
714 bool "STA2X11 Companion Chip Support"
715 depends on X86_32_NON_STANDARD && PCI
716 select SWIOTLB
717 select MFD_STA2X11
718 select GPIOLIB
719 ---help---
720 This adds support for boards based on the STA2X11 IO-Hub,
721 a.k.a. "ConneXt". The chip is used in place of the standard
722 PC chipset, so all "standard" peripherals are missing. If this
723 option is selected the kernel will still be able to boot on
724 standard PC machines.
725
726config X86_32_IRIS
727 tristate "Eurobraille/Iris poweroff module"
728 depends on X86_32
729 ---help---
730 The Iris machines from EuroBraille do not have APM or ACPI support
731 to shut themselves down properly. A special I/O sequence is
732 needed to do so, which is what this module does at
733 kernel shutdown.
734
735 This is only for Iris machines from EuroBraille.
736
737 If unused, say N.
738
739config SCHED_OMIT_FRAME_POINTER
740 def_bool y
741 prompt "Single-depth WCHAN output"
742 depends on X86
743 ---help---
744 Calculate simpler /proc/<PID>/wchan values. If this option
745 is disabled then wchan values will recurse back to the
746 caller function. This provides more accurate wchan values,
747 at the expense of slightly more scheduling overhead.
748
749 If in doubt, say "Y".
750
751menuconfig HYPERVISOR_GUEST
752 bool "Linux guest support"
753 ---help---
754 Say Y here to enable options for running Linux under various hyper-
755 visors. This option enables basic hypervisor detection and platform
756 setup.
757
758 If you say N, all options in this submenu will be skipped and
759 disabled, and Linux guest support won't be built in.
760
761if HYPERVISOR_GUEST
762
763config PARAVIRT
764 bool "Enable paravirtualization code"
765 ---help---
766 This changes the kernel so it can modify itself when it is run
767 under a hypervisor, potentially improving performance significantly
768 over full virtualization. However, when run without a hypervisor
769 the kernel is theoretically slower and slightly larger.
770
771config PARAVIRT_XXL
772 bool
773
774config PARAVIRT_DEBUG
775 bool "paravirt-ops debugging"
776 depends on PARAVIRT && DEBUG_KERNEL
777 ---help---
778 Enable to debug paravirt_ops internals. Specifically, BUG if
779 a paravirt_op is missing when it is called.
780
781config PARAVIRT_SPINLOCKS
782 bool "Paravirtualization layer for spinlocks"
783 depends on PARAVIRT && SMP
784 ---help---
785 Paravirtualized spinlocks allow a pvops backend to replace the
786 spinlock implementation with something virtualization-friendly
787 (for example, block the virtual CPU rather than spinning).
788
789 It has a minimal impact on native kernels and gives a nice performance
790 benefit on paravirtualized KVM / Xen kernels.
791
792 If you are unsure how to answer this question, answer Y.
793
794config X86_HV_CALLBACK_VECTOR
795 def_bool n
796
797source "arch/x86/xen/Kconfig"
798
799config KVM_GUEST
800 bool "KVM Guest support (including kvmclock)"
801 depends on PARAVIRT
802 select PARAVIRT_CLOCK
803 select ARCH_CPUIDLE_HALTPOLL
804 default y
805 ---help---
806 This option enables various optimizations for running under the KVM
807 hypervisor. It includes a paravirtualized clock, so that instead
808 of relying on a PIT (or probably other) emulation by the
809 underlying device model, the host provides the guest with
810 timing infrastructure such as time of day, and system time
811
812config ARCH_CPUIDLE_HALTPOLL
813 def_bool n
814 prompt "Disable host haltpoll when loading haltpoll driver"
815 help
816 If virtualized under KVM, disable host haltpoll.
817
818config PVH
819 bool "Support for running PVH guests"
820 ---help---
821 This option enables the PVH entry point for guest virtual machines
822 as specified in the x86/HVM direct boot ABI.
823
824config KVM_DEBUG_FS
825 bool "Enable debug information for KVM Guests in debugfs"
826 depends on KVM_GUEST && DEBUG_FS
827 ---help---
828 This option enables collection of various statistics for KVM guest.
829 Statistics are displayed in debugfs filesystem. Enabling this option
830 may incur significant overhead.
831
832config PARAVIRT_TIME_ACCOUNTING
833 bool "Paravirtual steal time accounting"
834 depends on PARAVIRT
835 ---help---
836 Select this option to enable fine granularity task steal time
837 accounting. Time spent executing other tasks in parallel with
838 the current vCPU is discounted from the vCPU power. To account for
839 that, there can be a small performance impact.
840
841 If in doubt, say N here.
842
843config PARAVIRT_CLOCK
844 bool
845
846config JAILHOUSE_GUEST
847 bool "Jailhouse non-root cell support"
848 depends on X86_64 && PCI
849 select X86_PM_TIMER
850 ---help---
851 This option allows to run Linux as guest in a Jailhouse non-root
852 cell. You can leave this option disabled if you only want to start
853 Jailhouse and run Linux afterwards in the root cell.
854
855config ACRN_GUEST
856 bool "ACRN Guest support"
857 depends on X86_64
858 select X86_HV_CALLBACK_VECTOR
859 help
860 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
861 a flexible, lightweight reference open-source hypervisor, built with
862 real-time and safety-criticality in mind. It is built for embedded
863 IOT with small footprint and real-time features. More details can be
864 found in https://projectacrn.org/.
865
866endif
867
868source "arch/x86/Kconfig.cpu"
869
870config HPET_TIMER
871 def_bool X86_64
872 prompt "HPET Timer Support" if X86_32
873 ---help---
874 Use the IA-PC HPET (High Precision Event Timer) to manage
875 time in preference to the PIT and RTC, if a HPET is
876 present.
877 HPET is the next generation timer replacing legacy 8254s.
878 The HPET provides a stable time base on SMP
879 systems, unlike the TSC, but it is more expensive to access,
880 as it is off-chip. The interface used is documented
881 in the HPET spec, revision 1.
882
883 You can safely choose Y here. However, HPET will only be
884 activated if the platform and the BIOS support this feature.
885 Otherwise the 8254 will be used for timing services.
886
887 Choose N to continue using the legacy 8254 timer.
888
889config HPET_EMULATE_RTC
890 def_bool y
891 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
892
893config APB_TIMER
894 def_bool y if X86_INTEL_MID
895 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
896 select DW_APB_TIMER
897 depends on X86_INTEL_MID && SFI
898 help
899 APB timer is the replacement for 8254, HPET on X86 MID platforms.
900 The APBT provides a stable time base on SMP
901 systems, unlike the TSC, but it is more expensive to access,
902 as it is off-chip. APB timers are always running regardless of CPU
903 C states, they are used as per CPU clockevent device when possible.
904
905
906
907config DMI
908 default y
909 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
910 bool "Enable DMI scanning" if EXPERT
911 ---help---
912 Enabled scanning of DMI to identify machine quirks. Say Y
913 here unless you have verified that your setup is not
914 affected by entries in the DMI blacklist. Required by PNP
915 BIOS code.
916
917config GART_IOMMU
918 bool "Old AMD GART IOMMU support"
919 select IOMMU_HELPER
920 select SWIOTLB
921 depends on X86_64 && PCI && AMD_NB
922 ---help---
923 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
924 GART based hardware IOMMUs.
925
926 The GART supports full DMA access for devices with 32-bit access
927 limitations, on systems with more than 3 GB. This is usually needed
928 for USB, sound, many IDE/SATA chipsets and some other devices.
929
930 Newer systems typically have a modern AMD IOMMU, supported via
931 the CONFIG_AMD_IOMMU=y config option.
932
933 In normal configurations this driver is only active when needed:
934 there's more than 3 GB of memory and the system contains a
935 32-bit limited device.
936
937 If unsure, say Y.
938
939config MAXSMP
940 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
941 depends on X86_64 && SMP && DEBUG_KERNEL
942 select CPUMASK_OFFSTACK
943 ---help---
944 Enable maximum number of CPUS and NUMA Nodes for this architecture.
945 If unsure, say N.
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961config NR_CPUS_RANGE_BEGIN
962 int
963 default NR_CPUS_RANGE_END if MAXSMP
964 default 1 if !SMP
965 default 2
966
967config NR_CPUS_RANGE_END
968 int
969 depends on X86_32
970 default 64 if SMP && X86_BIGSMP
971 default 8 if SMP && !X86_BIGSMP
972 default 1 if !SMP
973
974config NR_CPUS_RANGE_END
975 int
976 depends on X86_64
977 default 8192 if SMP && CPUMASK_OFFSTACK
978 default 512 if SMP && !CPUMASK_OFFSTACK
979 default 1 if !SMP
980
981config NR_CPUS_DEFAULT
982 int
983 depends on X86_32
984 default 32 if X86_BIGSMP
985 default 8 if SMP
986 default 1 if !SMP
987
988config NR_CPUS_DEFAULT
989 int
990 depends on X86_64
991 default 8192 if MAXSMP
992 default 64 if SMP
993 default 1 if !SMP
994
995config NR_CPUS
996 int "Maximum number of CPUs" if SMP && !MAXSMP
997 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
998 default NR_CPUS_DEFAULT
999 ---help---
1000 This allows you to specify the maximum number of CPUs which this
1001 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
1002 supported value is 8192, otherwise the maximum value is 512. The
1003 minimum value which makes sense is 2.
1004
1005 This is purely to save memory: each supported CPU adds about 8KB
1006 to the kernel image.
1007
1008config SCHED_SMT
1009 def_bool y if SMP
1010
1011config SCHED_MC
1012 def_bool y
1013 prompt "Multi-core scheduler support"
1014 depends on SMP
1015 ---help---
1016 Multi-core scheduler support improves the CPU scheduler's decision
1017 making when dealing with multi-core CPU chips at a cost of slightly
1018 increased overhead in some places. If unsure say N here.
1019
1020config SCHED_MC_PRIO
1021 bool "CPU core priorities scheduler support"
1022 depends on SCHED_MC && CPU_SUP_INTEL
1023 select X86_INTEL_PSTATE
1024 select CPU_FREQ
1025 default y
1026 ---help---
1027 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1028 core ordering determined at manufacturing time, which allows
1029 certain cores to reach higher turbo frequencies (when running
1030 single threaded workloads) than others.
1031
1032 Enabling this kernel feature teaches the scheduler about
1033 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1034 scheduler's CPU selection logic accordingly, so that higher
1035 overall system performance can be achieved.
1036
1037 This feature will have no effect on CPUs without this feature.
1038
1039 If unsure say Y here.
1040
1041config UP_LATE_INIT
1042 def_bool y
1043 depends on !SMP && X86_LOCAL_APIC
1044
1045config X86_UP_APIC
1046 bool "Local APIC support on uniprocessors" if !PCI_MSI
1047 default PCI_MSI
1048 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1049 ---help---
1050 A local APIC (Advanced Programmable Interrupt Controller) is an
1051 integrated interrupt controller in the CPU. If you have a single-CPU
1052 system which has a processor with a local APIC, you can say Y here to
1053 enable and use it. If you say Y here even though your machine doesn't
1054 have a local APIC, then the kernel will still run with no slowdown at
1055 all. The local APIC supports CPU-generated self-interrupts (timer,
1056 performance counters), and the NMI watchdog which detects hard
1057 lockups.
1058
1059config X86_UP_IOAPIC
1060 bool "IO-APIC support on uniprocessors"
1061 depends on X86_UP_APIC
1062 ---help---
1063 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1064 SMP-capable replacement for PC-style interrupt controllers. Most
1065 SMP systems and many recent uniprocessor systems have one.
1066
1067 If you have a single-CPU system with an IO-APIC, you can say Y here
1068 to use it. If you say Y here even though your machine doesn't have
1069 an IO-APIC, then the kernel will still run with no slowdown at all.
1070
1071config X86_LOCAL_APIC
1072 def_bool y
1073 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1074 select IRQ_DOMAIN_HIERARCHY
1075 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1076
1077config X86_IO_APIC
1078 def_bool y
1079 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1080
1081config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1082 bool "Reroute for broken boot IRQs"
1083 depends on X86_IO_APIC
1084 ---help---
1085 This option enables a workaround that fixes a source of
1086 spurious interrupts. This is recommended when threaded
1087 interrupt handling is used on systems where the generation of
1088 superfluous "boot interrupts" cannot be disabled.
1089
1090 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1091 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1092 kernel does during interrupt handling). On chipsets where this
1093 boot IRQ generation cannot be disabled, this workaround keeps
1094 the original IRQ line masked so that only the equivalent "boot
1095 IRQ" is delivered to the CPUs. The workaround also tells the
1096 kernel to set up the IRQ handler on the boot IRQ line. In this
1097 way only one interrupt is delivered to the kernel. Otherwise
1098 the spurious second interrupt may cause the kernel to bring
1099 down (vital) interrupt lines.
1100
1101 Only affects "broken" chipsets. Interrupt sharing may be
1102 increased on these systems.
1103
1104config X86_MCE
1105 bool "Machine Check / overheating reporting"
1106 select GENERIC_ALLOCATOR
1107 default y
1108 ---help---
1109 Machine Check support allows the processor to notify the
1110 kernel if it detects a problem (e.g. overheating, data corruption).
1111 The action the kernel takes depends on the severity of the problem,
1112 ranging from warning messages to halting the machine.
1113
1114config X86_MCELOG_LEGACY
1115 bool "Support for deprecated /dev/mcelog character device"
1116 depends on X86_MCE
1117 ---help---
1118 Enable support for /dev/mcelog which is needed by the old mcelog
1119 userspace logging daemon. Consider switching to the new generation
1120 rasdaemon solution.
1121
1122config X86_MCE_INTEL
1123 def_bool y
1124 prompt "Intel MCE features"
1125 depends on X86_MCE && X86_LOCAL_APIC
1126 ---help---
1127 Additional support for intel specific MCE features such as
1128 the thermal monitor.
1129
1130config X86_MCE_AMD
1131 def_bool y
1132 prompt "AMD MCE features"
1133 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1134 ---help---
1135 Additional support for AMD specific MCE features such as
1136 the DRAM Error Threshold.
1137
1138config X86_ANCIENT_MCE
1139 bool "Support for old Pentium 5 / WinChip machine checks"
1140 depends on X86_32 && X86_MCE
1141 ---help---
1142 Include support for machine check handling on old Pentium 5 or WinChip
1143 systems. These typically need to be enabled explicitly on the command
1144 line.
1145
1146config X86_MCE_THRESHOLD
1147 depends on X86_MCE_AMD || X86_MCE_INTEL
1148 def_bool y
1149
1150config X86_MCE_INJECT
1151 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1152 tristate "Machine check injector support"
1153 ---help---
1154 Provide support for injecting machine checks for testing purposes.
1155 If you don't know what a machine check is and you don't do kernel
1156 QA it is safe to say n.
1157
1158config X86_THERMAL_VECTOR
1159 def_bool y
1160 depends on X86_MCE_INTEL
1161
1162source "arch/x86/events/Kconfig"
1163
1164config X86_LEGACY_VM86
1165 bool "Legacy VM86 support"
1166 depends on X86_32
1167 ---help---
1168 This option allows user programs to put the CPU into V8086
1169 mode, which is an 80286-era approximation of 16-bit real mode.
1170
1171 Some very old versions of X and/or vbetool require this option
1172 for user mode setting. Similarly, DOSEMU will use it if
1173 available to accelerate real mode DOS programs. However, any
1174 recent version of DOSEMU, X, or vbetool should be fully
1175 functional even without kernel VM86 support, as they will all
1176 fall back to software emulation. Nevertheless, if you are using
1177 a 16-bit DOS program where 16-bit performance matters, vm86
1178 mode might be faster than emulation and you might want to
1179 enable this option.
1180
1181 Note that any app that works on a 64-bit kernel is unlikely to
1182 need this option, as 64-bit kernels don't, and can't, support
1183 V8086 mode. This option is also unrelated to 16-bit protected
1184 mode and is not needed to run most 16-bit programs under Wine.
1185
1186 Enabling this option increases the complexity of the kernel
1187 and slows down exception handling a tiny bit.
1188
1189 If unsure, say N here.
1190
1191config VM86
1192 bool
1193 default X86_LEGACY_VM86
1194
1195config X86_16BIT
1196 bool "Enable support for 16-bit segments" if EXPERT
1197 default y
1198 depends on MODIFY_LDT_SYSCALL
1199 ---help---
1200 This option is required by programs like Wine to run 16-bit
1201 protected mode legacy code on x86 processors. Disabling
1202 this option saves about 300 bytes on i386, or around 6K text
1203 plus 16K runtime memory on x86-64,
1204
1205config X86_ESPFIX32
1206 def_bool y
1207 depends on X86_16BIT && X86_32
1208
1209config X86_ESPFIX64
1210 def_bool y
1211 depends on X86_16BIT && X86_64
1212
1213config X86_VSYSCALL_EMULATION
1214 bool "Enable vsyscall emulation" if EXPERT
1215 default y
1216 depends on X86_64
1217 ---help---
1218 This enables emulation of the legacy vsyscall page. Disabling
1219 it is roughly equivalent to booting with vsyscall=none, except
1220 that it will also disable the helpful warning if a program
1221 tries to use a vsyscall. With this option set to N, offending
1222 programs will just segfault, citing addresses of the form
1223 0xffffffffff600?00.
1224
1225 This option is required by many programs built before 2013, and
1226 care should be used even with newer programs if set to N.
1227
1228 Disabling this option saves about 7K of kernel size and
1229 possibly 4K of additional runtime pagetable memory.
1230
1231config X86_IOPL_IOPERM
1232 bool "IOPERM and IOPL Emulation"
1233 default y
1234 ---help---
1235 This enables the ioperm() and iopl() syscalls which are necessary
1236 for legacy applications.
1237
1238 Legacy IOPL support is an overbroad mechanism which allows user
1239 space aside of accessing all 65536 I/O ports also to disable
1240 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1241 capabilities and permission from potentially active security
1242 modules.
1243
1244 The emulation restricts the functionality of the syscall to
1245 only allowing the full range I/O port access, but prevents the
1246 ability to disable interrupts from user space which would be
1247 granted if the hardware IOPL mechanism would be used.
1248
1249config TOSHIBA
1250 tristate "Toshiba Laptop support"
1251 depends on X86_32
1252 ---help---
1253 This adds a driver to safely access the System Management Mode of
1254 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1255 not work on models with a Phoenix BIOS. The System Management Mode
1256 is used to set the BIOS and power saving options on Toshiba portables.
1257
1258 For information on utilities to make use of this driver see the
1259 Toshiba Linux utilities web site at:
1260 <http://www.buzzard.org.uk/toshiba/>.
1261
1262 Say Y if you intend to run this kernel on a Toshiba portable.
1263 Say N otherwise.
1264
1265config I8K
1266 tristate "Dell i8k legacy laptop support"
1267 select HWMON
1268 select SENSORS_DELL_SMM
1269 ---help---
1270 This option enables legacy /proc/i8k userspace interface in hwmon
1271 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1272 temperature and allows controlling fan speeds of Dell laptops via
1273 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1274 it reports also power and hotkey status. For fan speed control is
1275 needed userspace package i8kutils.
1276
1277 Say Y if you intend to run this kernel on old Dell laptops or want to
1278 use userspace package i8kutils.
1279 Say N otherwise.
1280
1281config X86_REBOOTFIXUPS
1282 bool "Enable X86 board specific fixups for reboot"
1283 depends on X86_32
1284 ---help---
1285 This enables chipset and/or board specific fixups to be done
1286 in order to get reboot to work correctly. This is only needed on
1287 some combinations of hardware and BIOS. The symptom, for which
1288 this config is intended, is when reboot ends with a stalled/hung
1289 system.
1290
1291 Currently, the only fixup is for the Geode machines using
1292 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1293
1294 Say Y if you want to enable the fixup. Currently, it's safe to
1295 enable this option even if you don't need it.
1296 Say N otherwise.
1297
1298config MICROCODE
1299 bool "CPU microcode loading support"
1300 default y
1301 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1302 select FW_LOADER
1303 ---help---
1304 If you say Y here, you will be able to update the microcode on
1305 Intel and AMD processors. The Intel support is for the IA32 family,
1306 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1307 AMD support is for families 0x10 and later. You will obviously need
1308 the actual microcode binary data itself which is not shipped with
1309 the Linux kernel.
1310
1311 The preferred method to load microcode from a detached initrd is described
1312 in Documentation/x86/microcode.rst. For that you need to enable
1313 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1314 initrd for microcode blobs.
1315
1316 In addition, you can build the microcode into the kernel. For that you
1317 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1318 config option.
1319
1320config MICROCODE_INTEL
1321 bool "Intel microcode loading support"
1322 depends on MICROCODE
1323 default MICROCODE
1324 select FW_LOADER
1325 ---help---
1326 This options enables microcode patch loading support for Intel
1327 processors.
1328
1329 For the current Intel microcode data package go to
1330 <https://downloadcenter.intel.com> and search for
1331 'Linux Processor Microcode Data File'.
1332
1333config MICROCODE_AMD
1334 bool "AMD microcode loading support"
1335 depends on MICROCODE
1336 select FW_LOADER
1337 ---help---
1338 If you select this option, microcode patch loading support for AMD
1339 processors will be enabled.
1340
1341config MICROCODE_OLD_INTERFACE
1342 bool "Ancient loading interface (DEPRECATED)"
1343 default n
1344 depends on MICROCODE
1345 ---help---
1346 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1347 which was used by userspace tools like iucode_tool and microcode.ctl.
1348 It is inadequate because it runs too late to be able to properly
1349 load microcode on a machine and it needs special tools. Instead, you
1350 should've switched to the early loading method with the initrd or
1351 builtin microcode by now: Documentation/x86/microcode.rst
1352
1353config X86_MSR
1354 tristate "/dev/cpu/*/msr - Model-specific register support"
1355 ---help---
1356 This device gives privileged processes access to the x86
1357 Model-Specific Registers (MSRs). It is a character device with
1358 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1359 MSR accesses are directed to a specific CPU on multi-processor
1360 systems.
1361
1362config X86_CPUID
1363 tristate "/dev/cpu/*/cpuid - CPU information support"
1364 ---help---
1365 This device gives processes access to the x86 CPUID instruction to
1366 be executed on a specific processor. It is a character device
1367 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1368 /dev/cpu/31/cpuid.
1369
1370choice
1371 prompt "High Memory Support"
1372 default HIGHMEM4G
1373 depends on X86_32
1374
1375config NOHIGHMEM
1376 bool "off"
1377 ---help---
1378 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1379 However, the address space of 32-bit x86 processors is only 4
1380 Gigabytes large. That means that, if you have a large amount of
1381 physical memory, not all of it can be "permanently mapped" by the
1382 kernel. The physical memory that's not permanently mapped is called
1383 "high memory".
1384
1385 If you are compiling a kernel which will never run on a machine with
1386 more than 1 Gigabyte total physical RAM, answer "off" here (default
1387 choice and suitable for most users). This will result in a "3GB/1GB"
1388 split: 3GB are mapped so that each process sees a 3GB virtual memory
1389 space and the remaining part of the 4GB virtual memory space is used
1390 by the kernel to permanently map as much physical memory as
1391 possible.
1392
1393 If the machine has between 1 and 4 Gigabytes physical RAM, then
1394 answer "4GB" here.
1395
1396 If more than 4 Gigabytes is used then answer "64GB" here. This
1397 selection turns Intel PAE (Physical Address Extension) mode on.
1398 PAE implements 3-level paging on IA32 processors. PAE is fully
1399 supported by Linux, PAE mode is implemented on all recent Intel
1400 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1401 then the kernel will not boot on CPUs that don't support PAE!
1402
1403 The actual amount of total physical memory will either be
1404 auto detected or can be forced by using a kernel command line option
1405 such as "mem=256M". (Try "man bootparam" or see the documentation of
1406 your boot loader (lilo or loadlin) about how to pass options to the
1407 kernel at boot time.)
1408
1409 If unsure, say "off".
1410
1411config HIGHMEM4G
1412 bool "4GB"
1413 ---help---
1414 Select this if you have a 32-bit processor and between 1 and 4
1415 gigabytes of physical RAM.
1416
1417config HIGHMEM64G
1418 bool "64GB"
1419 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1420 select X86_PAE
1421 ---help---
1422 Select this if you have a 32-bit processor and more than 4
1423 gigabytes of physical RAM.
1424
1425endchoice
1426
1427choice
1428 prompt "Memory split" if EXPERT
1429 default VMSPLIT_3G
1430 depends on X86_32
1431 ---help---
1432 Select the desired split between kernel and user memory.
1433
1434 If the address range available to the kernel is less than the
1435 physical memory installed, the remaining memory will be available
1436 as "high memory". Accessing high memory is a little more costly
1437 than low memory, as it needs to be mapped into the kernel first.
1438 Note that increasing the kernel address space limits the range
1439 available to user programs, making the address space there
1440 tighter. Selecting anything other than the default 3G/1G split
1441 will also likely make your kernel incompatible with binary-only
1442 kernel modules.
1443
1444 If you are not absolutely sure what you are doing, leave this
1445 option alone!
1446
1447 config VMSPLIT_3G
1448 bool "3G/1G user/kernel split"
1449 config VMSPLIT_3G_OPT
1450 depends on !X86_PAE
1451 bool "3G/1G user/kernel split (for full 1G low memory)"
1452 config VMSPLIT_2G
1453 bool "2G/2G user/kernel split"
1454 config VMSPLIT_2G_OPT
1455 depends on !X86_PAE
1456 bool "2G/2G user/kernel split (for full 2G low memory)"
1457 config VMSPLIT_1G
1458 bool "1G/3G user/kernel split"
1459endchoice
1460
1461config PAGE_OFFSET
1462 hex
1463 default 0xB0000000 if VMSPLIT_3G_OPT
1464 default 0x80000000 if VMSPLIT_2G
1465 default 0x78000000 if VMSPLIT_2G_OPT
1466 default 0x40000000 if VMSPLIT_1G
1467 default 0xC0000000
1468 depends on X86_32
1469
1470config HIGHMEM
1471 def_bool y
1472 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1473
1474config X86_PAE
1475 bool "PAE (Physical Address Extension) Support"
1476 depends on X86_32 && !HIGHMEM4G
1477 select PHYS_ADDR_T_64BIT
1478 select SWIOTLB
1479 ---help---
1480 PAE is required for NX support, and furthermore enables
1481 larger swapspace support for non-overcommit purposes. It
1482 has the cost of more pagetable lookup overhead, and also
1483 consumes more pagetable space per process.
1484
1485config X86_5LEVEL
1486 bool "Enable 5-level page tables support"
1487 default y
1488 select DYNAMIC_MEMORY_LAYOUT
1489 select SPARSEMEM_VMEMMAP
1490 depends on X86_64
1491 ---help---
1492 5-level paging enables access to larger address space:
1493 upto 128 PiB of virtual address space and 4 PiB of
1494 physical address space.
1495
1496 It will be supported by future Intel CPUs.
1497
1498 A kernel with the option enabled can be booted on machines that
1499 support 4- or 5-level paging.
1500
1501 See Documentation/x86/x86_64/5level-paging.rst for more
1502 information.
1503
1504 Say N if unsure.
1505
1506config X86_DIRECT_GBPAGES
1507 def_bool y
1508 depends on X86_64
1509 ---help---
1510 Certain kernel features effectively disable kernel
1511 linear 1 GB mappings (even if the CPU otherwise
1512 supports them), so don't confuse the user by printing
1513 that we have them enabled.
1514
1515config X86_CPA_STATISTICS
1516 bool "Enable statistic for Change Page Attribute"
1517 depends on DEBUG_FS
1518 ---help---
1519 Expose statistics about the Change Page Attribute mechanism, which
1520 helps to determine the effectiveness of preserving large and huge
1521 page mappings when mapping protections are changed.
1522
1523config AMD_MEM_ENCRYPT
1524 bool "AMD Secure Memory Encryption (SME) support"
1525 depends on X86_64 && CPU_SUP_AMD
1526 select DYNAMIC_PHYSICAL_MASK
1527 select ARCH_USE_MEMREMAP_PROT
1528 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1529 ---help---
1530 Say yes to enable support for the encryption of system memory.
1531 This requires an AMD processor that supports Secure Memory
1532 Encryption (SME).
1533
1534config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1535 bool "Activate AMD Secure Memory Encryption (SME) by default"
1536 default y
1537 depends on AMD_MEM_ENCRYPT
1538 ---help---
1539 Say yes to have system memory encrypted by default if running on
1540 an AMD processor that supports Secure Memory Encryption (SME).
1541
1542 If set to Y, then the encryption of system memory can be
1543 deactivated with the mem_encrypt=off command line option.
1544
1545 If set to N, then the encryption of system memory can be
1546 activated with the mem_encrypt=on command line option.
1547
1548
1549config NUMA
1550 bool "NUMA Memory Allocation and Scheduler Support"
1551 depends on SMP
1552 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1553 default y if X86_BIGSMP
1554 ---help---
1555 Enable NUMA (Non-Uniform Memory Access) support.
1556
1557 The kernel will try to allocate memory used by a CPU on the
1558 local memory controller of the CPU and add some more
1559 NUMA awareness to the kernel.
1560
1561 For 64-bit this is recommended if the system is Intel Core i7
1562 (or later), AMD Opteron, or EM64T NUMA.
1563
1564 For 32-bit this is only needed if you boot a 32-bit
1565 kernel on a 64-bit NUMA platform.
1566
1567 Otherwise, you should say N.
1568
1569config AMD_NUMA
1570 def_bool y
1571 prompt "Old style AMD Opteron NUMA detection"
1572 depends on X86_64 && NUMA && PCI
1573 ---help---
1574 Enable AMD NUMA node topology detection. You should say Y here if
1575 you have a multi processor AMD system. This uses an old method to
1576 read the NUMA configuration directly from the builtin Northbridge
1577 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1578 which also takes priority if both are compiled in.
1579
1580config X86_64_ACPI_NUMA
1581 def_bool y
1582 prompt "ACPI NUMA detection"
1583 depends on X86_64 && NUMA && ACPI && PCI
1584 select ACPI_NUMA
1585 ---help---
1586 Enable ACPI SRAT based node topology detection.
1587
1588
1589
1590
1591
1592
1593config NODES_SPAN_OTHER_NODES
1594 def_bool y
1595 depends on X86_64_ACPI_NUMA
1596
1597config NUMA_EMU
1598 bool "NUMA emulation"
1599 depends on NUMA
1600 ---help---
1601 Enable NUMA emulation. A flat machine will be split
1602 into virtual nodes when booted with "numa=fake=N", where N is the
1603 number of nodes. This is only useful for debugging.
1604
1605config NODES_SHIFT
1606 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1607 range 1 10
1608 default "10" if MAXSMP
1609 default "6" if X86_64
1610 default "3"
1611 depends on NEED_MULTIPLE_NODES
1612 ---help---
1613 Specify the maximum number of NUMA Nodes available on the target
1614 system. Increases memory reserved to accommodate various tables.
1615
1616config ARCH_HAVE_MEMORY_PRESENT
1617 def_bool y
1618 depends on X86_32 && DISCONTIGMEM
1619
1620config ARCH_FLATMEM_ENABLE
1621 def_bool y
1622 depends on X86_32 && !NUMA
1623
1624config ARCH_DISCONTIGMEM_ENABLE
1625 def_bool n
1626 depends on NUMA && X86_32
1627 depends on BROKEN
1628
1629config ARCH_SPARSEMEM_ENABLE
1630 def_bool y
1631 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1632 select SPARSEMEM_STATIC if X86_32
1633 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1634
1635config ARCH_SPARSEMEM_DEFAULT
1636 def_bool X86_64 || (NUMA && X86_32)
1637
1638config ARCH_SELECT_MEMORY_MODEL
1639 def_bool y
1640 depends on ARCH_SPARSEMEM_ENABLE
1641
1642config ARCH_MEMORY_PROBE
1643 bool "Enable sysfs memory/probe interface"
1644 depends on X86_64 && MEMORY_HOTPLUG
1645 help
1646 This option enables a sysfs memory/probe interface for testing.
1647 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1648 If you are unsure how to answer this question, answer N.
1649
1650config ARCH_PROC_KCORE_TEXT
1651 def_bool y
1652 depends on X86_64 && PROC_KCORE
1653
1654config ILLEGAL_POINTER_VALUE
1655 hex
1656 default 0 if X86_32
1657 default 0xdead000000000000 if X86_64
1658
1659config X86_PMEM_LEGACY_DEVICE
1660 bool
1661
1662config X86_PMEM_LEGACY
1663 tristate "Support non-standard NVDIMMs and ADR protected memory"
1664 depends on PHYS_ADDR_T_64BIT
1665 depends on BLK_DEV
1666 select X86_PMEM_LEGACY_DEVICE
1667 select LIBNVDIMM
1668 help
1669 Treat memory marked using the non-standard e820 type of 12 as used
1670 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1671 The kernel will offer these regions to the 'pmem' driver so
1672 they can be used for persistent storage.
1673
1674 Say Y if unsure.
1675
1676config HIGHPTE
1677 bool "Allocate 3rd-level pagetables from highmem"
1678 depends on HIGHMEM
1679 ---help---
1680 The VM uses one page table entry for each page of physical memory.
1681 For systems with a lot of RAM, this can be wasteful of precious
1682 low memory. Setting this option will put user-space page table
1683 entries in high memory.
1684
1685config X86_CHECK_BIOS_CORRUPTION
1686 bool "Check for low memory corruption"
1687 ---help---
1688 Periodically check for memory corruption in low memory, which
1689 is suspected to be caused by BIOS. Even when enabled in the
1690 configuration, it is disabled at runtime. Enable it by
1691 setting "memory_corruption_check=1" on the kernel command
1692 line. By default it scans the low 64k of memory every 60
1693 seconds; see the memory_corruption_check_size and
1694 memory_corruption_check_period parameters in
1695 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1696
1697 When enabled with the default parameters, this option has
1698 almost no overhead, as it reserves a relatively small amount
1699 of memory and scans it infrequently. It both detects corruption
1700 and prevents it from affecting the running system.
1701
1702 It is, however, intended as a diagnostic tool; if repeatable
1703 BIOS-originated corruption always affects the same memory,
1704 you can use memmap= to prevent the kernel from using that
1705 memory.
1706
1707config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1708 bool "Set the default setting of memory_corruption_check"
1709 depends on X86_CHECK_BIOS_CORRUPTION
1710 default y
1711 ---help---
1712 Set whether the default state of memory_corruption_check is
1713 on or off.
1714
1715config X86_RESERVE_LOW
1716 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1717 default 64
1718 range 4 640
1719 ---help---
1720 Specify the amount of low memory to reserve for the BIOS.
1721
1722 The first page contains BIOS data structures that the kernel
1723 must not use, so that page must always be reserved.
1724
1725 By default we reserve the first 64K of physical RAM, as a
1726 number of BIOSes are known to corrupt that memory range
1727 during events such as suspend/resume or monitor cable
1728 insertion, so it must not be used by the kernel.
1729
1730 You can set this to 4 if you are absolutely sure that you
1731 trust the BIOS to get all its memory reservations and usages
1732 right. If you know your BIOS have problems beyond the
1733 default 64K area, you can set this to 640 to avoid using the
1734 entire low memory range.
1735
1736 If you have doubts about the BIOS (e.g. suspend/resume does
1737 not work or there's kernel crashes after certain hardware
1738 hotplug events) then you might want to enable
1739 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1740 typical corruption patterns.
1741
1742 Leave this to the default value of 64 if you are unsure.
1743
1744config MATH_EMULATION
1745 bool
1746 depends on MODIFY_LDT_SYSCALL
1747 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1748 ---help---
1749 Linux can emulate a math coprocessor (used for floating point
1750 operations) if you don't have one. 486DX and Pentium processors have
1751 a math coprocessor built in, 486SX and 386 do not, unless you added
1752 a 487DX or 387, respectively. (The messages during boot time can
1753 give you some hints here ["man dmesg"].) Everyone needs either a
1754 coprocessor or this emulation.
1755
1756 If you don't have a math coprocessor, you need to say Y here; if you
1757 say Y here even though you have a coprocessor, the coprocessor will
1758 be used nevertheless. (This behavior can be changed with the kernel
1759 command line option "no387", which comes handy if your coprocessor
1760 is broken. Try "man bootparam" or see the documentation of your boot
1761 loader (lilo or loadlin) about how to pass options to the kernel at
1762 boot time.) This means that it is a good idea to say Y here if you
1763 intend to use this kernel on different machines.
1764
1765 More information about the internals of the Linux math coprocessor
1766 emulation can be found in <file:arch/x86/math-emu/README>.
1767
1768 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1769 kernel, it won't hurt.
1770
1771config MTRR
1772 def_bool y
1773 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1774 ---help---
1775 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1776 the Memory Type Range Registers (MTRRs) may be used to control
1777 processor access to memory ranges. This is most useful if you have
1778 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1779 allows bus write transfers to be combined into a larger transfer
1780 before bursting over the PCI/AGP bus. This can increase performance
1781 of image write operations 2.5 times or more. Saying Y here creates a
1782 /proc/mtrr file which may be used to manipulate your processor's
1783 MTRRs. Typically the X server should use this.
1784
1785 This code has a reasonably generic interface so that similar
1786 control registers on other processors can be easily supported
1787 as well:
1788
1789 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1790 Registers (ARRs) which provide a similar functionality to MTRRs. For
1791 these, the ARRs are used to emulate the MTRRs.
1792 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1793 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1794 write-combining. All of these processors are supported by this code
1795 and it makes sense to say Y here if you have one of them.
1796
1797 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1798 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1799 can lead to all sorts of problems, so it's good to say Y here.
1800
1801 You can safely say Y even if your machine doesn't have MTRRs, you'll
1802 just add about 9 KB to your kernel.
1803
1804 See <file:Documentation/x86/mtrr.rst> for more information.
1805
1806config MTRR_SANITIZER
1807 def_bool y
1808 prompt "MTRR cleanup support"
1809 depends on MTRR
1810 ---help---
1811 Convert MTRR layout from continuous to discrete, so X drivers can
1812 add writeback entries.
1813
1814 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1815 The largest mtrr entry size for a continuous block can be set with
1816 mtrr_chunk_size.
1817
1818 If unsure, say Y.
1819
1820config MTRR_SANITIZER_ENABLE_DEFAULT
1821 int "MTRR cleanup enable value (0-1)"
1822 range 0 1
1823 default "0"
1824 depends on MTRR_SANITIZER
1825 ---help---
1826 Enable mtrr cleanup default value
1827
1828config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1829 int "MTRR cleanup spare reg num (0-7)"
1830 range 0 7
1831 default "1"
1832 depends on MTRR_SANITIZER
1833 ---help---
1834 mtrr cleanup spare entries default, it can be changed via
1835 mtrr_spare_reg_nr=N on the kernel command line.
1836
1837config X86_PAT
1838 def_bool y
1839 prompt "x86 PAT support" if EXPERT
1840 depends on MTRR
1841 ---help---
1842 Use PAT attributes to setup page level cache control.
1843
1844 PATs are the modern equivalents of MTRRs and are much more
1845 flexible than MTRRs.
1846
1847 Say N here if you see bootup problems (boot crash, boot hang,
1848 spontaneous reboots) or a non-working video driver.
1849
1850 If unsure, say Y.
1851
1852config ARCH_USES_PG_UNCACHED
1853 def_bool y
1854 depends on X86_PAT
1855
1856config ARCH_RANDOM
1857 def_bool y
1858 prompt "x86 architectural random number generator" if EXPERT
1859 ---help---
1860 Enable the x86 architectural RDRAND instruction
1861 (Intel Bull Mountain technology) to generate random numbers.
1862 If supported, this is a high bandwidth, cryptographically
1863 secure hardware random number generator.
1864
1865config X86_SMAP
1866 def_bool y
1867 prompt "Supervisor Mode Access Prevention" if EXPERT
1868 ---help---
1869 Supervisor Mode Access Prevention (SMAP) is a security
1870 feature in newer Intel processors. There is a small
1871 performance cost if this enabled and turned on; there is
1872 also a small increase in the kernel size if this is enabled.
1873
1874 If unsure, say Y.
1875
1876config X86_UMIP
1877 def_bool y
1878 depends on CPU_SUP_INTEL || CPU_SUP_AMD
1879 prompt "User Mode Instruction Prevention" if EXPERT
1880 ---help---
1881 User Mode Instruction Prevention (UMIP) is a security feature in
1882 some x86 processors. If enabled, a general protection fault is
1883 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1884 executed in user mode. These instructions unnecessarily expose
1885 information about the hardware state.
1886
1887 The vast majority of applications do not use these instructions.
1888 For the very few that do, software emulation is provided in
1889 specific cases in protected and virtual-8086 modes. Emulated
1890 results are dummy.
1891
1892config X86_INTEL_MEMORY_PROTECTION_KEYS
1893 prompt "Intel Memory Protection Keys"
1894 def_bool y
1895
1896 depends on CPU_SUP_INTEL && X86_64
1897 select ARCH_USES_HIGH_VMA_FLAGS
1898 select ARCH_HAS_PKEYS
1899 ---help---
1900 Memory Protection Keys provides a mechanism for enforcing
1901 page-based protections, but without requiring modification of the
1902 page tables when an application changes protection domains.
1903
1904 For details, see Documentation/core-api/protection-keys.rst
1905
1906 If unsure, say y.
1907
1908choice
1909 prompt "TSX enable mode"
1910 depends on CPU_SUP_INTEL
1911 default X86_INTEL_TSX_MODE_OFF
1912 help
1913 Intel's TSX (Transactional Synchronization Extensions) feature
1914 allows to optimize locking protocols through lock elision which
1915 can lead to a noticeable performance boost.
1916
1917 On the other hand it has been shown that TSX can be exploited
1918 to form side channel attacks (e.g. TAA) and chances are there
1919 will be more of those attacks discovered in the future.
1920
1921 Therefore TSX is not enabled by default (aka tsx=off). An admin
1922 might override this decision by tsx=on the command line parameter.
1923 Even with TSX enabled, the kernel will attempt to enable the best
1924 possible TAA mitigation setting depending on the microcode available
1925 for the particular machine.
1926
1927 This option allows to set the default tsx mode between tsx=on, =off
1928 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1929 details.
1930
1931 Say off if not sure, auto if TSX is in use but it should be used on safe
1932 platforms or on if TSX is in use and the security aspect of tsx is not
1933 relevant.
1934
1935config X86_INTEL_TSX_MODE_OFF
1936 bool "off"
1937 help
1938 TSX is disabled if possible - equals to tsx=off command line parameter.
1939
1940config X86_INTEL_TSX_MODE_ON
1941 bool "on"
1942 help
1943 TSX is always enabled on TSX capable HW - equals the tsx=on command
1944 line parameter.
1945
1946config X86_INTEL_TSX_MODE_AUTO
1947 bool "auto"
1948 help
1949 TSX is enabled on TSX capable HW that is believed to be safe against
1950 side channel attacks- equals the tsx=auto command line parameter.
1951endchoice
1952
1953config EFI
1954 bool "EFI runtime service support"
1955 depends on ACPI
1956 select UCS2_STRING
1957 select EFI_RUNTIME_WRAPPERS
1958 ---help---
1959 This enables the kernel to use EFI runtime services that are
1960 available (such as the EFI variable services).
1961
1962 This option is only useful on systems that have EFI firmware.
1963 In addition, you should use the latest ELILO loader available
1964 at <http://elilo.sourceforge.net> in order to take advantage
1965 of EFI runtime services. However, even with this option, the
1966 resultant kernel should continue to boot on existing non-EFI
1967 platforms.
1968
1969config EFI_STUB
1970 bool "EFI stub support"
1971 depends on EFI && !X86_USE_3DNOW
1972 depends on $(cc-option,-mabi=ms) || X86_32
1973 select RELOCATABLE
1974 ---help---
1975 This kernel feature allows a bzImage to be loaded directly
1976 by EFI firmware without the use of a bootloader.
1977
1978 See Documentation/admin-guide/efi-stub.rst for more information.
1979
1980config EFI_MIXED
1981 bool "EFI mixed-mode support"
1982 depends on EFI_STUB && X86_64
1983 ---help---
1984 Enabling this feature allows a 64-bit kernel to be booted
1985 on a 32-bit firmware, provided that your CPU supports 64-bit
1986 mode.
1987
1988 Note that it is not possible to boot a mixed-mode enabled
1989 kernel via the EFI boot stub - a bootloader that supports
1990 the EFI handover protocol must be used.
1991
1992 If unsure, say N.
1993
1994config SECCOMP
1995 def_bool y
1996 prompt "Enable seccomp to safely compute untrusted bytecode"
1997 ---help---
1998 This kernel feature is useful for number crunching applications
1999 that may need to compute untrusted bytecode during their
2000 execution. By using pipes or other transports made available to
2001 the process as file descriptors supporting the read/write
2002 syscalls, it's possible to isolate those applications in
2003 their own address space using seccomp. Once seccomp is
2004 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
2005 and the task is only allowed to execute a few safe syscalls
2006 defined by each seccomp mode.
2007
2008 If unsure, say Y. Only embedded should say N here.
2009
2010source "kernel/Kconfig.hz"
2011
2012config KEXEC
2013 bool "kexec system call"
2014 select KEXEC_CORE
2015 ---help---
2016 kexec is a system call that implements the ability to shutdown your
2017 current kernel, and to start another kernel. It is like a reboot
2018 but it is independent of the system firmware. And like a reboot
2019 you can start any kernel with it, not just Linux.
2020
2021 The name comes from the similarity to the exec system call.
2022
2023 It is an ongoing process to be certain the hardware in a machine
2024 is properly shutdown, so do not be surprised if this code does not
2025 initially work for you. As of this writing the exact hardware
2026 interface is strongly in flux, so no good recommendation can be
2027 made.
2028
2029config KEXEC_FILE
2030 bool "kexec file based system call"
2031 select KEXEC_CORE
2032 select BUILD_BIN2C
2033 depends on X86_64
2034 depends on CRYPTO=y
2035 depends on CRYPTO_SHA256=y
2036 ---help---
2037 This is new version of kexec system call. This system call is
2038 file based and takes file descriptors as system call argument
2039 for kernel and initramfs as opposed to list of segments as
2040 accepted by previous system call.
2041
2042config ARCH_HAS_KEXEC_PURGATORY
2043 def_bool KEXEC_FILE
2044
2045config KEXEC_SIG
2046 bool "Verify kernel signature during kexec_file_load() syscall"
2047 depends on KEXEC_FILE
2048 ---help---
2049
2050 This option makes the kexec_file_load() syscall check for a valid
2051 signature of the kernel image. The image can still be loaded without
2052 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2053 there's a signature that we can check, then it must be valid.
2054
2055 In addition to this option, you need to enable signature
2056 verification for the corresponding kernel image type being
2057 loaded in order for this to work.
2058
2059config KEXEC_SIG_FORCE
2060 bool "Require a valid signature in kexec_file_load() syscall"
2061 depends on KEXEC_SIG
2062 ---help---
2063 This option makes kernel signature verification mandatory for
2064 the kexec_file_load() syscall.
2065
2066config KEXEC_BZIMAGE_VERIFY_SIG
2067 bool "Enable bzImage signature verification support"
2068 depends on KEXEC_SIG
2069 depends on SIGNED_PE_FILE_VERIFICATION
2070 select SYSTEM_TRUSTED_KEYRING
2071 ---help---
2072 Enable bzImage signature verification support.
2073
2074config CRASH_DUMP
2075 bool "kernel crash dumps"
2076 depends on X86_64 || (X86_32 && HIGHMEM)
2077 ---help---
2078 Generate crash dump after being started by kexec.
2079 This should be normally only set in special crash dump kernels
2080 which are loaded in the main kernel with kexec-tools into
2081 a specially reserved region and then later executed after
2082 a crash by kdump/kexec. The crash dump kernel must be compiled
2083 to a memory address not used by the main kernel or BIOS using
2084 PHYSICAL_START, or it must be built as a relocatable image
2085 (CONFIG_RELOCATABLE=y).
2086 For more details see Documentation/admin-guide/kdump/kdump.rst
2087
2088config KEXEC_JUMP
2089 bool "kexec jump"
2090 depends on KEXEC && HIBERNATION
2091 ---help---
2092 Jump between original kernel and kexeced kernel and invoke
2093 code in physical address mode via KEXEC
2094
2095config PHYSICAL_START
2096 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2097 default "0x1000000"
2098 ---help---
2099 This gives the physical address where the kernel is loaded.
2100
2101 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2102 bzImage will decompress itself to above physical address and
2103 run from there. Otherwise, bzImage will run from the address where
2104 it has been loaded by the boot loader and will ignore above physical
2105 address.
2106
2107 In normal kdump cases one does not have to set/change this option
2108 as now bzImage can be compiled as a completely relocatable image
2109 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2110 address. This option is mainly useful for the folks who don't want
2111 to use a bzImage for capturing the crash dump and want to use a
2112 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2113 to be specifically compiled to run from a specific memory area
2114 (normally a reserved region) and this option comes handy.
2115
2116 So if you are using bzImage for capturing the crash dump,
2117 leave the value here unchanged to 0x1000000 and set
2118 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2119 for capturing the crash dump change this value to start of
2120 the reserved region. In other words, it can be set based on
2121 the "X" value as specified in the "crashkernel=YM@XM"
2122 command line boot parameter passed to the panic-ed
2123 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2124 for more details about crash dumps.
2125
2126 Usage of bzImage for capturing the crash dump is recommended as
2127 one does not have to build two kernels. Same kernel can be used
2128 as production kernel and capture kernel. Above option should have
2129 gone away after relocatable bzImage support is introduced. But it
2130 is present because there are users out there who continue to use
2131 vmlinux for dump capture. This option should go away down the
2132 line.
2133
2134 Don't change this unless you know what you are doing.
2135
2136config RELOCATABLE
2137 bool "Build a relocatable kernel"
2138 default y
2139 ---help---
2140 This builds a kernel image that retains relocation information
2141 so it can be loaded someplace besides the default 1MB.
2142 The relocations tend to make the kernel binary about 10% larger,
2143 but are discarded at runtime.
2144
2145 One use is for the kexec on panic case where the recovery kernel
2146 must live at a different physical address than the primary
2147 kernel.
2148
2149 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2150 it has been loaded at and the compile time physical address
2151 (CONFIG_PHYSICAL_START) is used as the minimum location.
2152
2153config RANDOMIZE_BASE
2154 bool "Randomize the address of the kernel image (KASLR)"
2155 depends on RELOCATABLE
2156 default y
2157 ---help---
2158 In support of Kernel Address Space Layout Randomization (KASLR),
2159 this randomizes the physical address at which the kernel image
2160 is decompressed and the virtual address where the kernel
2161 image is mapped, as a security feature that deters exploit
2162 attempts relying on knowledge of the location of kernel
2163 code internals.
2164
2165 On 64-bit, the kernel physical and virtual addresses are
2166 randomized separately. The physical address will be anywhere
2167 between 16MB and the top of physical memory (up to 64TB). The
2168 virtual address will be randomized from 16MB up to 1GB (9 bits
2169 of entropy). Note that this also reduces the memory space
2170 available to kernel modules from 1.5GB to 1GB.
2171
2172 On 32-bit, the kernel physical and virtual addresses are
2173 randomized together. They will be randomized from 16MB up to
2174 512MB (8 bits of entropy).
2175
2176 Entropy is generated using the RDRAND instruction if it is
2177 supported. If RDTSC is supported, its value is mixed into
2178 the entropy pool as well. If neither RDRAND nor RDTSC are
2179 supported, then entropy is read from the i8254 timer. The
2180 usable entropy is limited by the kernel being built using
2181 2GB addressing, and that PHYSICAL_ALIGN must be at a
2182 minimum of 2MB. As a result, only 10 bits of entropy are
2183 theoretically possible, but the implementations are further
2184 limited due to memory layouts.
2185
2186 If unsure, say Y.
2187
2188
2189config X86_NEED_RELOCS
2190 def_bool y
2191 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2192
2193config PHYSICAL_ALIGN
2194 hex "Alignment value to which kernel should be aligned"
2195 default "0x200000"
2196 range 0x2000 0x1000000 if X86_32
2197 range 0x200000 0x1000000 if X86_64
2198 ---help---
2199 This value puts the alignment restrictions on physical address
2200 where kernel is loaded and run from. Kernel is compiled for an
2201 address which meets above alignment restriction.
2202
2203 If bootloader loads the kernel at a non-aligned address and
2204 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2205 address aligned to above value and run from there.
2206
2207 If bootloader loads the kernel at a non-aligned address and
2208 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2209 load address and decompress itself to the address it has been
2210 compiled for and run from there. The address for which kernel is
2211 compiled already meets above alignment restrictions. Hence the
2212 end result is that kernel runs from a physical address meeting
2213 above alignment restrictions.
2214
2215 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2216 this value must be a multiple of 0x200000.
2217
2218 Don't change this unless you know what you are doing.
2219
2220config DYNAMIC_MEMORY_LAYOUT
2221 bool
2222 ---help---
2223 This option makes base addresses of vmalloc and vmemmap as well as
2224 __PAGE_OFFSET movable during boot.
2225
2226config RANDOMIZE_MEMORY
2227 bool "Randomize the kernel memory sections"
2228 depends on X86_64
2229 depends on RANDOMIZE_BASE
2230 select DYNAMIC_MEMORY_LAYOUT
2231 default RANDOMIZE_BASE
2232 ---help---
2233 Randomizes the base virtual address of kernel memory sections
2234 (physical memory mapping, vmalloc & vmemmap). This security feature
2235 makes exploits relying on predictable memory locations less reliable.
2236
2237 The order of allocations remains unchanged. Entropy is generated in
2238 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2239 configuration have in average 30,000 different possible virtual
2240 addresses for each memory section.
2241
2242 If unsure, say Y.
2243
2244config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2245 hex "Physical memory mapping padding" if EXPERT
2246 depends on RANDOMIZE_MEMORY
2247 default "0xa" if MEMORY_HOTPLUG
2248 default "0x0"
2249 range 0x1 0x40 if MEMORY_HOTPLUG
2250 range 0x0 0x40
2251 ---help---
2252 Define the padding in terabytes added to the existing physical
2253 memory size during kernel memory randomization. It is useful
2254 for memory hotplug support but reduces the entropy available for
2255 address randomization.
2256
2257 If unsure, leave at the default value.
2258
2259config HOTPLUG_CPU
2260 def_bool y
2261 depends on SMP
2262
2263config BOOTPARAM_HOTPLUG_CPU0
2264 bool "Set default setting of cpu0_hotpluggable"
2265 depends on HOTPLUG_CPU
2266 ---help---
2267 Set whether default state of cpu0_hotpluggable is on or off.
2268
2269 Say Y here to enable CPU0 hotplug by default. If this switch
2270 is turned on, there is no need to give cpu0_hotplug kernel
2271 parameter and the CPU0 hotplug feature is enabled by default.
2272
2273 Please note: there are two known CPU0 dependencies if you want
2274 to enable the CPU0 hotplug feature either by this switch or by
2275 cpu0_hotplug kernel parameter.
2276
2277 First, resume from hibernate or suspend always starts from CPU0.
2278 So hibernate and suspend are prevented if CPU0 is offline.
2279
2280 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2281 offline if any interrupt can not migrate out of CPU0. There may
2282 be other CPU0 dependencies.
2283
2284 Please make sure the dependencies are under your control before
2285 you enable this feature.
2286
2287 Say N if you don't want to enable CPU0 hotplug feature by default.
2288 You still can enable the CPU0 hotplug feature at boot by kernel
2289 parameter cpu0_hotplug.
2290
2291config DEBUG_HOTPLUG_CPU0
2292 def_bool n
2293 prompt "Debug CPU0 hotplug"
2294 depends on HOTPLUG_CPU
2295 ---help---
2296 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2297 soon as possible and boots up userspace with CPU0 offlined. User
2298 can online CPU0 back after boot time.
2299
2300 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2301 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2302 compilation or giving cpu0_hotplug kernel parameter at boot.
2303
2304 If unsure, say N.
2305
2306config COMPAT_VDSO
2307 def_bool n
2308 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2309 depends on COMPAT_32
2310 ---help---
2311 Certain buggy versions of glibc will crash if they are
2312 presented with a 32-bit vDSO that is not mapped at the address
2313 indicated in its segment table.
2314
2315 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2316 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2317 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2318 the only released version with the bug, but OpenSUSE 9
2319 contains a buggy "glibc 2.3.2".
2320
2321 The symptom of the bug is that everything crashes on startup, saying:
2322 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2323
2324 Saying Y here changes the default value of the vdso32 boot
2325 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2326 This works around the glibc bug but hurts performance.
2327
2328 If unsure, say N: if you are compiling your own kernel, you
2329 are unlikely to be using a buggy version of glibc.
2330
2331choice
2332 prompt "vsyscall table for legacy applications"
2333 depends on X86_64
2334 default LEGACY_VSYSCALL_XONLY
2335 help
2336 Legacy user code that does not know how to find the vDSO expects
2337 to be able to issue three syscalls by calling fixed addresses in
2338 kernel space. Since this location is not randomized with ASLR,
2339 it can be used to assist security vulnerability exploitation.
2340
2341 This setting can be changed at boot time via the kernel command
2342 line parameter vsyscall=[emulate|xonly|none].
2343
2344 On a system with recent enough glibc (2.14 or newer) and no
2345 static binaries, you can say None without a performance penalty
2346 to improve security.
2347
2348 If unsure, select "Emulate execution only".
2349
2350 config LEGACY_VSYSCALL_EMULATE
2351 bool "Full emulation"
2352 help
2353 The kernel traps and emulates calls into the fixed vsyscall
2354 address mapping. This makes the mapping non-executable, but
2355 it still contains readable known contents, which could be
2356 used in certain rare security vulnerability exploits. This
2357 configuration is recommended when using legacy userspace
2358 that still uses vsyscalls along with legacy binary
2359 instrumentation tools that require code to be readable.
2360
2361 An example of this type of legacy userspace is running
2362 Pin on an old binary that still uses vsyscalls.
2363
2364 config LEGACY_VSYSCALL_XONLY
2365 bool "Emulate execution only"
2366 help
2367 The kernel traps and emulates calls into the fixed vsyscall
2368 address mapping and does not allow reads. This
2369 configuration is recommended when userspace might use the
2370 legacy vsyscall area but support for legacy binary
2371 instrumentation of legacy code is not needed. It mitigates
2372 certain uses of the vsyscall area as an ASLR-bypassing
2373 buffer.
2374
2375 config LEGACY_VSYSCALL_NONE
2376 bool "None"
2377 help
2378 There will be no vsyscall mapping at all. This will
2379 eliminate any risk of ASLR bypass due to the vsyscall
2380 fixed address mapping. Attempts to use the vsyscalls
2381 will be reported to dmesg, so that either old or
2382 malicious userspace programs can be identified.
2383
2384endchoice
2385
2386config CMDLINE_BOOL
2387 bool "Built-in kernel command line"
2388 ---help---
2389 Allow for specifying boot arguments to the kernel at
2390 build time. On some systems (e.g. embedded ones), it is
2391 necessary or convenient to provide some or all of the
2392 kernel boot arguments with the kernel itself (that is,
2393 to not rely on the boot loader to provide them.)
2394
2395 To compile command line arguments into the kernel,
2396 set this option to 'Y', then fill in the
2397 boot arguments in CONFIG_CMDLINE.
2398
2399 Systems with fully functional boot loaders (i.e. non-embedded)
2400 should leave this option set to 'N'.
2401
2402config CMDLINE
2403 string "Built-in kernel command string"
2404 depends on CMDLINE_BOOL
2405 default ""
2406 ---help---
2407 Enter arguments here that should be compiled into the kernel
2408 image and used at boot time. If the boot loader provides a
2409 command line at boot time, it is appended to this string to
2410 form the full kernel command line, when the system boots.
2411
2412 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2413 change this behavior.
2414
2415 In most cases, the command line (whether built-in or provided
2416 by the boot loader) should specify the device for the root
2417 file system.
2418
2419config CMDLINE_OVERRIDE
2420 bool "Built-in command line overrides boot loader arguments"
2421 depends on CMDLINE_BOOL
2422 ---help---
2423 Set this option to 'Y' to have the kernel ignore the boot loader
2424 command line, and use ONLY the built-in command line.
2425
2426 This is used to work around broken boot loaders. This should
2427 be set to 'N' under normal conditions.
2428
2429config MODIFY_LDT_SYSCALL
2430 bool "Enable the LDT (local descriptor table)" if EXPERT
2431 default y
2432 ---help---
2433 Linux can allow user programs to install a per-process x86
2434 Local Descriptor Table (LDT) using the modify_ldt(2) system
2435 call. This is required to run 16-bit or segmented code such as
2436 DOSEMU or some Wine programs. It is also used by some very old
2437 threading libraries.
2438
2439 Enabling this feature adds a small amount of overhead to
2440 context switches and increases the low-level kernel attack
2441 surface. Disabling it removes the modify_ldt(2) system call.
2442
2443 Saying 'N' here may make sense for embedded or server kernels.
2444
2445source "kernel/livepatch/Kconfig"
2446
2447endmenu
2448
2449config ARCH_HAS_ADD_PAGES
2450 def_bool y
2451 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2452
2453config ARCH_ENABLE_MEMORY_HOTPLUG
2454 def_bool y
2455 depends on X86_64 || (X86_32 && HIGHMEM)
2456
2457config ARCH_ENABLE_MEMORY_HOTREMOVE
2458 def_bool y
2459 depends on MEMORY_HOTPLUG
2460
2461config USE_PERCPU_NUMA_NODE_ID
2462 def_bool y
2463 depends on NUMA
2464
2465config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2466 def_bool y
2467 depends on X86_64 || X86_PAE
2468
2469config ARCH_ENABLE_HUGEPAGE_MIGRATION
2470 def_bool y
2471 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2472
2473config ARCH_ENABLE_THP_MIGRATION
2474 def_bool y
2475 depends on X86_64 && TRANSPARENT_HUGEPAGE
2476
2477menu "Power management and ACPI options"
2478
2479config ARCH_HIBERNATION_HEADER
2480 def_bool y
2481 depends on HIBERNATION
2482
2483source "kernel/power/Kconfig"
2484
2485source "drivers/acpi/Kconfig"
2486
2487source "drivers/sfi/Kconfig"
2488
2489config X86_APM_BOOT
2490 def_bool y
2491 depends on APM
2492
2493menuconfig APM
2494 tristate "APM (Advanced Power Management) BIOS support"
2495 depends on X86_32 && PM_SLEEP
2496 ---help---
2497 APM is a BIOS specification for saving power using several different
2498 techniques. This is mostly useful for battery powered laptops with
2499 APM compliant BIOSes. If you say Y here, the system time will be
2500 reset after a RESUME operation, the /proc/apm device will provide
2501 battery status information, and user-space programs will receive
2502 notification of APM "events" (e.g. battery status change).
2503
2504 If you select "Y" here, you can disable actual use of the APM
2505 BIOS by passing the "apm=off" option to the kernel at boot time.
2506
2507 Note that the APM support is almost completely disabled for
2508 machines with more than one CPU.
2509
2510 In order to use APM, you will need supporting software. For location
2511 and more information, read <file:Documentation/power/apm-acpi.rst>
2512 and the Battery Powered Linux mini-HOWTO, available from
2513 <http://www.tldp.org/docs.html
2514
2515 This driver does not spin down disk drives (see the hdparm(8)
2516 manpage ("man 8 hdparm") for that), and it doesn't turn off
2517 VESA-compliant "green" monitors.
2518
2519 This driver does not support the TI 4000M TravelMate and the ACER
2520 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2521 desktop machines also don't have compliant BIOSes, and this driver
2522 may cause those machines to panic during the boot phase.
2523
2524 Generally, if you don't have a battery in your machine, there isn't
2525 much point in using this driver and you should say N. If you get
2526 random kernel OOPSes or reboots that don't seem to be related to
2527 anything, try disabling/enabling this option (or disabling/enabling
2528 APM in your BIOS).
2529
2530 Some other things you should try when experiencing seemingly random,
2531 "weird" problems:
2532
2533 1) make sure that you have enough swap space and that it is
2534 enabled.
2535 2) pass the "no-hlt" option to the kernel
2536 3) switch on floating point emulation in the kernel and pass
2537 the "no387" option to the kernel
2538 4) pass the "floppy=nodma" option to the kernel
2539 5) pass the "mem=4M" option to the kernel (thereby disabling
2540 all but the first 4 MB of RAM)
2541 6) make sure that the CPU is not over clocked.
2542 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2543 8) disable the cache from your BIOS settings
2544 9) install a fan for the video card or exchange video RAM
2545 10) install a better fan for the CPU
2546 11) exchange RAM chips
2547 12) exchange the motherboard.
2548
2549 To compile this driver as a module, choose M here: the
2550 module will be called apm.
2551
2552if APM
2553
2554config APM_IGNORE_USER_SUSPEND
2555 bool "Ignore USER SUSPEND"
2556 ---help---
2557 This option will ignore USER SUSPEND requests. On machines with a
2558 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2559 series notebooks, it is necessary to say Y because of a BIOS bug.
2560
2561config APM_DO_ENABLE
2562 bool "Enable PM at boot time"
2563 ---help---
2564 Enable APM features at boot time. From page 36 of the APM BIOS
2565 specification: "When disabled, the APM BIOS does not automatically
2566 power manage devices, enter the Standby State, enter the Suspend
2567 State, or take power saving steps in response to CPU Idle calls."
2568 This driver will make CPU Idle calls when Linux is idle (unless this
2569 feature is turned off -- see "Do CPU IDLE calls", below). This
2570 should always save battery power, but more complicated APM features
2571 will be dependent on your BIOS implementation. You may need to turn
2572 this option off if your computer hangs at boot time when using APM
2573 support, or if it beeps continuously instead of suspending. Turn
2574 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2575 T400CDT. This is off by default since most machines do fine without
2576 this feature.
2577
2578config APM_CPU_IDLE
2579 depends on CPU_IDLE
2580 bool "Make CPU Idle calls when idle"
2581 ---help---
2582 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2583 On some machines, this can activate improved power savings, such as
2584 a slowed CPU clock rate, when the machine is idle. These idle calls
2585 are made after the idle loop has run for some length of time (e.g.,
2586 333 mS). On some machines, this will cause a hang at boot time or
2587 whenever the CPU becomes idle. (On machines with more than one CPU,
2588 this option does nothing.)
2589
2590config APM_DISPLAY_BLANK
2591 bool "Enable console blanking using APM"
2592 ---help---
2593 Enable console blanking using the APM. Some laptops can use this to
2594 turn off the LCD backlight when the screen blanker of the Linux
2595 virtual console blanks the screen. Note that this is only used by
2596 the virtual console screen blanker, and won't turn off the backlight
2597 when using the X Window system. This also doesn't have anything to
2598 do with your VESA-compliant power-saving monitor. Further, this
2599 option doesn't work for all laptops -- it might not turn off your
2600 backlight at all, or it might print a lot of errors to the console,
2601 especially if you are using gpm.
2602
2603config APM_ALLOW_INTS
2604 bool "Allow interrupts during APM BIOS calls"
2605 ---help---
2606 Normally we disable external interrupts while we are making calls to
2607 the APM BIOS as a measure to lessen the effects of a badly behaving
2608 BIOS implementation. The BIOS should reenable interrupts if it
2609 needs to. Unfortunately, some BIOSes do not -- especially those in
2610 many of the newer IBM Thinkpads. If you experience hangs when you
2611 suspend, try setting this to Y. Otherwise, say N.
2612
2613endif
2614
2615source "drivers/cpufreq/Kconfig"
2616
2617source "drivers/cpuidle/Kconfig"
2618
2619source "drivers/idle/Kconfig"
2620
2621endmenu
2622
2623
2624menu "Bus options (PCI etc.)"
2625
2626choice
2627 prompt "PCI access mode"
2628 depends on X86_32 && PCI
2629 default PCI_GOANY
2630 ---help---
2631 On PCI systems, the BIOS can be used to detect the PCI devices and
2632 determine their configuration. However, some old PCI motherboards
2633 have BIOS bugs and may crash if this is done. Also, some embedded
2634 PCI-based systems don't have any BIOS at all. Linux can also try to
2635 detect the PCI hardware directly without using the BIOS.
2636
2637 With this option, you can specify how Linux should detect the
2638 PCI devices. If you choose "BIOS", the BIOS will be used,
2639 if you choose "Direct", the BIOS won't be used, and if you
2640 choose "MMConfig", then PCI Express MMCONFIG will be used.
2641 If you choose "Any", the kernel will try MMCONFIG, then the
2642 direct access method and falls back to the BIOS if that doesn't
2643 work. If unsure, go with the default, which is "Any".
2644
2645config PCI_GOBIOS
2646 bool "BIOS"
2647
2648config PCI_GOMMCONFIG
2649 bool "MMConfig"
2650
2651config PCI_GODIRECT
2652 bool "Direct"
2653
2654config PCI_GOOLPC
2655 bool "OLPC XO-1"
2656 depends on OLPC
2657
2658config PCI_GOANY
2659 bool "Any"
2660
2661endchoice
2662
2663config PCI_BIOS
2664 def_bool y
2665 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2666
2667
2668config PCI_DIRECT
2669 def_bool y
2670 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2671
2672config PCI_MMCONFIG
2673 bool "Support mmconfig PCI config space access" if X86_64
2674 default y
2675 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2676 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2677
2678config PCI_OLPC
2679 def_bool y
2680 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2681
2682config PCI_XEN
2683 def_bool y
2684 depends on PCI && XEN
2685 select SWIOTLB_XEN
2686
2687config MMCONF_FAM10H
2688 def_bool y
2689 depends on X86_64 && PCI_MMCONFIG && ACPI
2690
2691config PCI_CNB20LE_QUIRK
2692 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2693 depends on PCI
2694 help
2695 Read the PCI windows out of the CNB20LE host bridge. This allows
2696 PCI hotplug to work on systems with the CNB20LE chipset which do
2697 not have ACPI.
2698
2699 There's no public spec for this chipset, and this functionality
2700 is known to be incomplete.
2701
2702 You should say N unless you know you need this.
2703
2704config ISA_BUS
2705 bool "ISA bus support on modern systems" if EXPERT
2706 help
2707 Expose ISA bus device drivers and options available for selection and
2708 configuration. Enable this option if your target machine has an ISA
2709 bus. ISA is an older system, displaced by PCI and newer bus
2710 architectures -- if your target machine is modern, it probably does
2711 not have an ISA bus.
2712
2713 If unsure, say N.
2714
2715
2716config ISA_DMA_API
2717 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2718 default y
2719 help
2720 Enables ISA-style DMA support for devices requiring such controllers.
2721 If unsure, say Y.
2722
2723if X86_32
2724
2725config ISA
2726 bool "ISA support"
2727 ---help---
2728 Find out whether you have ISA slots on your motherboard. ISA is the
2729 name of a bus system, i.e. the way the CPU talks to the other stuff
2730 inside your box. Other bus systems are PCI, EISA, MicroChannel
2731 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2732 newer boards don't support it. If you have ISA, say Y, otherwise N.
2733
2734config SCx200
2735 tristate "NatSemi SCx200 support"
2736 ---help---
2737 This provides basic support for National Semiconductor's
2738 (now AMD's) Geode processors. The driver probes for the
2739 PCI-IDs of several on-chip devices, so its a good dependency
2740 for other scx200_* drivers.
2741
2742 If compiled as a module, the driver is named scx200.
2743
2744config SCx200HR_TIMER
2745 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2746 depends on SCx200
2747 default y
2748 ---help---
2749 This driver provides a clocksource built upon the on-chip
2750 27MHz high-resolution timer. Its also a workaround for
2751 NSC Geode SC-1100's buggy TSC, which loses time when the
2752 processor goes idle (as is done by the scheduler). The
2753 other workaround is idle=poll boot option.
2754
2755config OLPC
2756 bool "One Laptop Per Child support"
2757 depends on !X86_PAE
2758 select GPIOLIB
2759 select OF
2760 select OF_PROMTREE
2761 select IRQ_DOMAIN
2762 select OLPC_EC
2763 ---help---
2764 Add support for detecting the unique features of the OLPC
2765 XO hardware.
2766
2767config OLPC_XO1_PM
2768 bool "OLPC XO-1 Power Management"
2769 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2770 ---help---
2771 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2772
2773config OLPC_XO1_RTC
2774 bool "OLPC XO-1 Real Time Clock"
2775 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2776 ---help---
2777 Add support for the XO-1 real time clock, which can be used as a
2778 programmable wakeup source.
2779
2780config OLPC_XO1_SCI
2781 bool "OLPC XO-1 SCI extras"
2782 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2783 depends on INPUT=y
2784 select POWER_SUPPLY
2785 ---help---
2786 Add support for SCI-based features of the OLPC XO-1 laptop:
2787 - EC-driven system wakeups
2788 - Power button
2789 - Ebook switch
2790 - Lid switch
2791 - AC adapter status updates
2792 - Battery status updates
2793
2794config OLPC_XO15_SCI
2795 bool "OLPC XO-1.5 SCI extras"
2796 depends on OLPC && ACPI
2797 select POWER_SUPPLY
2798 ---help---
2799 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2800 - EC-driven system wakeups
2801 - AC adapter status updates
2802 - Battery status updates
2803
2804config ALIX
2805 bool "PCEngines ALIX System Support (LED setup)"
2806 select GPIOLIB
2807 ---help---
2808 This option enables system support for the PCEngines ALIX.
2809 At present this just sets up LEDs for GPIO control on
2810 ALIX2/3/6 boards. However, other system specific setup should
2811 get added here.
2812
2813 Note: You must still enable the drivers for GPIO and LED support
2814 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2815
2816 Note: You have to set alix.force=1 for boards with Award BIOS.
2817
2818config NET5501
2819 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2820 select GPIOLIB
2821 ---help---
2822 This option enables system support for the Soekris Engineering net5501.
2823
2824config GEOS
2825 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2826 select GPIOLIB
2827 depends on DMI
2828 ---help---
2829 This option enables system support for the Traverse Technologies GEOS.
2830
2831config TS5500
2832 bool "Technologic Systems TS-5500 platform support"
2833 depends on MELAN
2834 select CHECK_SIGNATURE
2835 select NEW_LEDS
2836 select LEDS_CLASS
2837 ---help---
2838 This option enables system support for the Technologic Systems TS-5500.
2839
2840endif
2841
2842config AMD_NB
2843 def_bool y
2844 depends on CPU_SUP_AMD && PCI
2845
2846config X86_SYSFB
2847 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2848 help
2849 Firmwares often provide initial graphics framebuffers so the BIOS,
2850 bootloader or kernel can show basic video-output during boot for
2851 user-guidance and debugging. Historically, x86 used the VESA BIOS
2852 Extensions and EFI-framebuffers for this, which are mostly limited
2853 to x86.
2854 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2855 framebuffers so the new generic system-framebuffer drivers can be
2856 used on x86. If the framebuffer is not compatible with the generic
2857 modes, it is advertised as fallback platform framebuffer so legacy
2858 drivers like efifb, vesafb and uvesafb can pick it up.
2859 If this option is not selected, all system framebuffers are always
2860 marked as fallback platform framebuffers as usual.
2861
2862 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2863 not be able to pick up generic system framebuffers if this option
2864 is selected. You are highly encouraged to enable simplefb as
2865 replacement if you select this option. simplefb can correctly deal
2866 with generic system framebuffers. But you should still keep vesafb
2867 and others enabled as fallback if a system framebuffer is
2868 incompatible with simplefb.
2869
2870 If unsure, say Y.
2871
2872endmenu
2873
2874
2875menu "Binary Emulations"
2876
2877config IA32_EMULATION
2878 bool "IA32 Emulation"
2879 depends on X86_64
2880 select ARCH_WANT_OLD_COMPAT_IPC
2881 select BINFMT_ELF
2882 select COMPAT_BINFMT_ELF
2883 select COMPAT_OLD_SIGACTION
2884 ---help---
2885 Include code to run legacy 32-bit programs under a
2886 64-bit kernel. You should likely turn this on, unless you're
2887 100% sure that you don't have any 32-bit programs left.
2888
2889config IA32_AOUT
2890 tristate "IA32 a.out support"
2891 depends on IA32_EMULATION
2892 depends on BROKEN
2893 ---help---
2894 Support old a.out binaries in the 32bit emulation.
2895
2896config X86_X32
2897 bool "x32 ABI for 64-bit mode"
2898 depends on X86_64
2899 ---help---
2900 Include code to run binaries for the x32 native 32-bit ABI
2901 for 64-bit processors. An x32 process gets access to the
2902 full 64-bit register file and wide data path while leaving
2903 pointers at 32 bits for smaller memory footprint.
2904
2905 You will need a recent binutils (2.22 or later) with
2906 elf32_x86_64 support enabled to compile a kernel with this
2907 option set.
2908
2909config COMPAT_32
2910 def_bool y
2911 depends on IA32_EMULATION || X86_32
2912 select HAVE_UID16
2913 select OLD_SIGSUSPEND3
2914
2915config COMPAT
2916 def_bool y
2917 depends on IA32_EMULATION || X86_X32
2918
2919if COMPAT
2920config COMPAT_FOR_U64_ALIGNMENT
2921 def_bool y
2922
2923config SYSVIPC_COMPAT
2924 def_bool y
2925 depends on SYSVIPC
2926endif
2927
2928endmenu
2929
2930
2931config HAVE_ATOMIC_IOMAP
2932 def_bool y
2933 depends on X86_32
2934
2935source "drivers/firmware/Kconfig"
2936
2937source "arch/x86/kvm/Kconfig"
2938