mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option
[linux-2.6-block.git] / arch / x86 / Kconfig
CommitLineData
b2441318 1# SPDX-License-Identifier: GPL-2.0
daa93fab
SR
2# Select 32 or 64 bit
3config 64BIT
104daea1
MY
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
8f9ca475 6 ---help---
daa93fab
SR
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
3120e25e
JB
11 def_bool y
12 depends on !64BIT
341c787e
IM
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
15 select CLKSRC_I8253
16 select CLONE_BACKWARDS
117ed454 17 select HAVE_DEBUG_STACKOVERFLOW
341c787e
IM
18 select MODULES_USE_ELF_REL
19 select OLD_SIGACTION
7ac87074 20 select GENERIC_VDSO_32
daa93fab
SR
21
22config X86_64
3120e25e
JB
23 def_bool y
24 depends on 64BIT
d94e0685 25 # Options that are inherently 64-bit kernel only:
4eb0716e 26 select ARCH_HAS_GIGANTIC_PAGE
c12d3362 27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
d94e0685
IM
28 select ARCH_USE_CMPXCHG_LOCKREF
29 select HAVE_ARCH_SOFT_DIRTY
30 select MODULES_USE_ELF_RELA
f616ab59 31 select NEED_DMA_MAP_STATE
09230cbc 32 select SWIOTLB
1032c0ba 33
518049d9
SRV
34config FORCE_DYNAMIC_FTRACE
35 def_bool y
36 depends on X86_32
37 depends on FUNCTION_TRACER
38 select DYNAMIC_FTRACE
39 help
40 We keep the static function tracing (!DYNAMIC_FTRACE) around
41 in order to test the non static function tracing in the
42 generic code, as other architectures still use it. But we
43 only need to keep it around for x86_64. No need to keep it
44 for x86_32. For x86_32, force DYNAMIC_FTRACE.
d94e0685
IM
45#
46# Arch settings
47#
48# ( Note that options that are marked 'if X86_64' could in principle be
49# ported to 32-bit as well. )
50#
8d5fffb9 51config X86
3c2362e6 52 def_bool y
c763ea26
IM
53 #
54 # Note: keep this list sorted alphabetically
55 #
6471b825
IM
56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
942fa985 58 select ARCH_32BIT_OFF_T if X86_32
2a21ad57 59 select ARCH_CLOCKSOURCE_INIT
c763ea26 60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
fa5b6ec9 61 select ARCH_HAS_DEBUG_VIRTUAL
21266be9 62 select ARCH_HAS_DEVMEM_IS_ALLOWED
6471b825 63 select ARCH_HAS_ELF_RANDOMIZE
72d93104 64 select ARCH_HAS_FAST_MULTIPLIER
316d097c 65 select ARCH_HAS_FILTER_PGPROT
6974f0c4 66 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 67 select ARCH_HAS_GCOV_PROFILE_ALL
5c9a8750 68 select ARCH_HAS_KCOV if X86_64
0c9c1d56 69 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 70 select ARCH_HAS_MEMBARRIER_SYNC_CORE
0ebeea8c 71 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
c763ea26 72 select ARCH_HAS_PMEM_API if X86_64
17596731 73 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 74 select ARCH_HAS_PTE_SPECIAL
0aed55af 75 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
092b31aa 76 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
d2852a22 77 select ARCH_HAS_SET_MEMORY
d253ca0c 78 select ARCH_HAS_SET_DIRECT_MAP
ad21fc4f
LA
79 select ARCH_HAS_STRICT_KERNEL_RWX
80 select ARCH_HAS_STRICT_MODULE_RWX
ac1ab12a 81 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
25c619e5 82 select ARCH_HAS_SYSCALL_WRAPPER
c6d30853 83 select ARCH_HAS_UBSAN_SANITIZE_ALL
6471b825
IM
84 select ARCH_HAVE_NMI_SAFE_CMPXCHG
85 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 86 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 87 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 88 select ARCH_STACKWALK
2c870e61 89 select ARCH_SUPPORTS_ACPI
6471b825 90 select ARCH_SUPPORTS_ATOMIC_RMW
6471b825
IM
91 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
92 select ARCH_USE_BUILTIN_BSWAP
6471b825
IM
93 select ARCH_USE_QUEUED_RWLOCKS
94 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 95 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 96 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 97 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 98 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
3876d4a3 99 select ARCH_WANT_HUGE_PMD_SHARE
38d8b4e6 100 select ARCH_WANTS_THP_SWAP if X86_64
10916706 101 select BUILDTIME_TABLE_SORT
6471b825 102 select CLKEVT_I8253
6471b825
IM
103 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
104 select CLOCKSOURCE_WATCHDOG
6471b825 105 select DCACHE_WORD_ACCESS
45471cd9
LT
106 select EDAC_ATOMIC_SCRUB
107 select EDAC_SUPPORT
6471b825
IM
108 select GENERIC_CLOCKEVENTS
109 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
110 select GENERIC_CLOCKEVENTS_MIN_ADJUST
111 select GENERIC_CMOS_UPDATE
112 select GENERIC_CPU_AUTOPROBE
61dc0f55 113 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 114 select GENERIC_EARLY_IOREMAP
6471b825
IM
115 select GENERIC_FIND_FIRST_BIT
116 select GENERIC_IOMAP
c7d6c9dd 117 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 118 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 119 select GENERIC_IRQ_MIGRATION if SMP
6471b825 120 select GENERIC_IRQ_PROBE
c201c917 121 select GENERIC_IRQ_RESERVATION_MODE
6471b825
IM
122 select GENERIC_IRQ_SHOW
123 select GENERIC_PENDING_IRQ if SMP
2ae27137 124 select GENERIC_PTDUMP
6471b825
IM
125 select GENERIC_SMP_IDLE_THREAD
126 select GENERIC_STRNCPY_FROM_USER
127 select GENERIC_STRNLEN_USER
128 select GENERIC_TIME_VSYSCALL
7ac87074 129 select GENERIC_GETTIMEOFDAY
550a77a7 130 select GENERIC_VDSO_TIME_NS
39656e83 131 select GUP_GET_PTE_LOW_HIGH if X86_PAE
17e5888e 132 select HARDIRQS_SW_RESEND
7edaeb68 133 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
6471b825
IM
134 select HAVE_ACPI_APEI if ACPI
135 select HAVE_ACPI_APEI_NMI if ACPI
136 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
6471b825
IM
137 select HAVE_ARCH_AUDITSYSCALL
138 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
139 select HAVE_ARCH_JUMP_LABEL
b34006c4 140 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 141 select HAVE_ARCH_KASAN if X86_64
0609ae01 142 select HAVE_ARCH_KASAN_VMALLOC if X86_64
6471b825 143 select HAVE_ARCH_KGDB
9e08f57d
DC
144 select HAVE_ARCH_MMAP_RND_BITS if MMU
145 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 146 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 147 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 148 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 149 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 150 select HAVE_ARCH_STACKLEAK
6471b825
IM
151 select HAVE_ARCH_TRACEHOOK
152 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 153 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 154 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
e37e43a4 155 select HAVE_ARCH_VMAP_STACK if X86_64
c763ea26 156 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 157 select HAVE_ASM_MODVERSIONS
6471b825
IM
158 select HAVE_CMPXCHG_DOUBLE
159 select HAVE_CMPXCHG_LOCAL
160 select HAVE_CONTEXT_TRACKING if X86_64
c1bd55f9 161 select HAVE_COPY_THREAD_TLS
cf4db259 162 select HAVE_C_RECORDMCOUNT
6471b825 163 select HAVE_DEBUG_KMEMLEAK
6471b825 164 select HAVE_DMA_CONTIGUOUS
677aa9f7 165 select HAVE_DYNAMIC_FTRACE
06aeaaea 166 select HAVE_DYNAMIC_FTRACE_WITH_REGS
562955fe 167 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
03f5781b 168 select HAVE_EBPF_JIT
58340a07 169 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 170 select HAVE_EISA
5f56a5df 171 select HAVE_EXIT_THREAD
67a929e0 172 select HAVE_FAST_GUP
644e0e8d 173 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 174 select HAVE_FTRACE_MCOUNT_RECORD
6471b825
IM
175 select HAVE_FUNCTION_GRAPH_TRACER
176 select HAVE_FUNCTION_TRACER
6b90bd4b 177 select HAVE_GCC_PLUGINS
6471b825
IM
178 select HAVE_HW_BREAKPOINT
179 select HAVE_IDE
180 select HAVE_IOREMAP_PROT
181 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
182 select HAVE_IRQ_TIME_ACCOUNTING
2e9f3bdd 183 select HAVE_KERNEL_BZIP2
6471b825
IM
184 select HAVE_KERNEL_GZIP
185 select HAVE_KERNEL_LZ4
2e9f3bdd 186 select HAVE_KERNEL_LZMA
13510997 187 select HAVE_KERNEL_LZO
6471b825
IM
188 select HAVE_KERNEL_XZ
189 select HAVE_KPROBES
190 select HAVE_KPROBES_ON_FTRACE
540adea3 191 select HAVE_FUNCTION_ERROR_INJECTION
6471b825
IM
192 select HAVE_KRETPROBES
193 select HAVE_KVM
194 select HAVE_LIVEPATCH if X86_64
0102752e 195 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 196 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 197 select HAVE_MOVE_PMD
42a0bb3f 198 select HAVE_NMI
6471b825
IM
199 select HAVE_OPROFILE
200 select HAVE_OPTPROBES
201 select HAVE_PCSPKR_PLATFORM
202 select HAVE_PERF_EVENTS
c01d4323 203 select HAVE_PERF_EVENTS_NMI
92e5aae4 204 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 205 select HAVE_PCI
c5e63197 206 select HAVE_PERF_REGS
c5ebcedb 207 select HAVE_PERF_USER_STACK_DUMP
ff2e6d72 208 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
6471b825 209 select HAVE_REGS_AND_STACK_ACCESS_API
6415b38b 210 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
3c88ee19 211 select HAVE_FUNCTION_ARG_ACCESS_API
d148eac0 212 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
c763ea26 213 select HAVE_STACK_VALIDATION if X86_64
d6761b8f 214 select HAVE_RSEQ
6471b825 215 select HAVE_SYSCALL_TRACEPOINTS
6471b825 216 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 217 select HAVE_USER_RETURN_NOTIFIER
7ac87074 218 select HAVE_GENERIC_VDSO
05736e4a 219 select HOTPLUG_SMT if SMP
c0185808 220 select IRQ_FORCED_THREADING
86596f0a 221 select NEED_SG_DMA_LENGTH
2eac9c2d 222 select PCI_DOMAINS if PCI
625210cf 223 select PCI_LOCKLESS_CONFIG if PCI
6471b825 224 select PERF_EVENTS
3195ef59 225 select RTC_LIB
d6faca40 226 select RTC_MC146818_LIB
6471b825 227 select SPARSE_IRQ
83fe27ea 228 select SRCU
6471b825 229 select SYSCTL_EXCEPTION_TRACE
15f4eae7 230 select THREAD_INFO_IN_TASK
6471b825
IM
231 select USER_STACKTRACE_SUPPORT
232 select VIRT_TO_BUS
6471b825 233 select X86_FEATURE_NAMES if PROC_FS
0c608dad 234 select PROC_PID_ARCH_STATUS if PROC_FS
9e2b4be3 235 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
7d8330a5 236
ba7e4d13 237config INSTRUCTION_DECODER
3120e25e
JB
238 def_bool y
239 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 240
51b26ada
LT
241config OUTPUT_FORMAT
242 string
243 default "elf32-i386" if X86_32
244 default "elf64-x86-64" if X86_64
245
8d5fffb9 246config LOCKDEP_SUPPORT
3c2362e6 247 def_bool y
8d5fffb9
SR
248
249config STACKTRACE_SUPPORT
3c2362e6 250 def_bool y
8d5fffb9 251
8d5fffb9 252config MMU
3c2362e6 253 def_bool y
8d5fffb9 254
9e08f57d
DC
255config ARCH_MMAP_RND_BITS_MIN
256 default 28 if 64BIT
257 default 8
258
259config ARCH_MMAP_RND_BITS_MAX
260 default 32 if 64BIT
261 default 16
262
263config ARCH_MMAP_RND_COMPAT_BITS_MIN
264 default 8
265
266config ARCH_MMAP_RND_COMPAT_BITS_MAX
267 default 16
268
8d5fffb9
SR
269config SBUS
270 bool
271
272config GENERIC_ISA_DMA
3120e25e
JB
273 def_bool y
274 depends on ISA_DMA_API
8d5fffb9 275
8d5fffb9 276config GENERIC_BUG
3c2362e6 277 def_bool y
8d5fffb9 278 depends on BUG
b93a531e
JB
279 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
280
281config GENERIC_BUG_RELATIVE_POINTERS
282 bool
8d5fffb9 283
8d5fffb9 284config ARCH_MAY_HAVE_PC_FDC
3120e25e
JB
285 def_bool y
286 depends on ISA_DMA_API
8d5fffb9 287
1032c0ba
SR
288config GENERIC_CALIBRATE_DELAY
289 def_bool y
290
9a0b8415 291config ARCH_HAS_CPU_RELAX
292 def_bool y
293
1b27d05b
PE
294config ARCH_HAS_CACHE_LINE_SIZE
295 def_bool y
296
316d097c
DH
297config ARCH_HAS_FILTER_PGPROT
298 def_bool y
299
dd5af90a 300config HAVE_SETUP_PER_CPU_AREA
89c9c4c5 301 def_bool y
b32ef636 302
08fc4580
TH
303config NEED_PER_CPU_EMBED_FIRST_CHUNK
304 def_bool y
305
306config NEED_PER_CPU_PAGE_FIRST_CHUNK
11124411
TH
307 def_bool y
308
801e4062
JB
309config ARCH_HIBERNATION_POSSIBLE
310 def_bool y
801e4062 311
f4cb5700
JB
312config ARCH_SUSPEND_POSSIBLE
313 def_bool y
f4cb5700 314
53313b2c
SC
315config ARCH_WANT_GENERAL_HUGETLB
316 def_bool y
317
8d5fffb9 318config ZONE_DMA32
e0fd24a3 319 def_bool y if X86_64
8d5fffb9 320
8d5fffb9 321config AUDIT_ARCH
e0fd24a3 322 def_bool y if X86_64
8d5fffb9 323
6a11f75b
AM
324config ARCH_SUPPORTS_DEBUG_PAGEALLOC
325 def_bool y
326
d6f2d75a
AR
327config KASAN_SHADOW_OFFSET
328 hex
329 depends on KASAN
330 default 0xdffffc0000000000
331
69575d38
SW
332config HAVE_INTEL_TXT
333 def_bool y
6ea30386 334 depends on INTEL_IOMMU && ACPI
69575d38 335
6b0c3d44
SR
336config X86_32_SMP
337 def_bool y
338 depends on X86_32 && SMP
339
340config X86_64_SMP
341 def_bool y
342 depends on X86_64 && SMP
343
ccbeed3a
TH
344config X86_32_LAZY_GS
345 def_bool y
8458f8c2 346 depends on X86_32 && !STACKPROTECTOR
ccbeed3a 347
2b144498
SD
348config ARCH_SUPPORTS_UPROBES
349 def_bool y
350
d20642f0
RH
351config FIX_EARLYCON_MEM
352 def_bool y
353
94d49eb3
KS
354config DYNAMIC_PHYSICAL_MASK
355 bool
356
98233368
KS
357config PGTABLE_LEVELS
358 int
77ef56e4 359 default 5 if X86_5LEVEL
98233368
KS
360 default 4 if X86_64
361 default 3 if X86_PAE
362 default 2
363
2a61f474
MY
364config CC_HAS_SANE_STACKPROTECTOR
365 bool
366 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
367 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
368 help
369 We have to make sure stack protector is unconditionally disabled if
370 the compiler produces broken code.
371
506f1d07
SR
372menu "Processor type and features"
373
5ee71535
RD
374config ZONE_DMA
375 bool "DMA memory allocation support" if EXPERT
376 default y
377 help
378 DMA memory allocation support allows devices with less than 32-bit
379 addressing to allocate within the first 16MB of address space.
380 Disable if no such devices will be used.
381
382 If unsure, say Y.
383
506f1d07
SR
384config SMP
385 bool "Symmetric multi-processing support"
386 ---help---
387 This enables support for systems with more than one CPU. If you have
4a474157
RG
388 a system with only one CPU, say N. If you have a system with more
389 than one CPU, say Y.
506f1d07 390
4a474157 391 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
392 machines, but will use only one CPU of a multiprocessor machine. If
393 you say Y here, the kernel will run on many, but not all,
4a474157 394 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
395 will run faster if you say N here.
396
397 Note that if you say Y here and choose architecture "586" or
398 "Pentium" under "Processor family", the kernel will not work on 486
399 architectures. Similarly, multiprocessor kernels for the "PPro"
400 architecture may not work on all Pentium based boards.
401
402 People using multiprocessor machines who say Y here should also say
403 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
404 Management" code will be disabled if you say Y here.
405
cb1aaebe 406 See also <file:Documentation/x86/i386/IO-APIC.rst>,
4f4cfa6c 407 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
408 <http://www.tldp.org/docs.html#howto>.
409
410 If you don't know what to do here, say N.
411
9def39be
JT
412config X86_FEATURE_NAMES
413 bool "Processor feature human-readable names" if EMBEDDED
414 default y
415 ---help---
416 This option compiles in a table of x86 feature bits and corresponding
417 names. This is required to support /proc/cpuinfo and a few kernel
418 messages. You can disable this to save space, at the expense of
419 making those few kernel messages show numeric feature bits instead.
420
421 If in doubt, say Y.
422
06cd9a7d
YL
423config X86_X2APIC
424 bool "Support x2apic"
19e3d60d 425 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
06cd9a7d
YL
426 ---help---
427 This enables x2apic support on CPUs that have this feature.
428
429 This allows 32-bit apic IDs (so it can support very large systems),
430 and accesses the local apic via MSRs not via mmio.
431
06cd9a7d
YL
432 If you don't know what to do here, say N.
433
6695c85b 434config X86_MPPARSE
6e87f9b7 435 bool "Enable MPS table" if ACPI || SFI
7a527688 436 default y
5ab74722 437 depends on X86_LOCAL_APIC
8f9ca475 438 ---help---
6695c85b
YL
439 For old smp systems that do not have proper acpi support. Newer systems
440 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 441
ddd70cf9 442config GOLDFISH
b03b016f
KK
443 def_bool y
444 depends on X86_GOLDFISH
ddd70cf9 445
76b04384
DW
446config RETPOLINE
447 bool "Avoid speculative indirect branches in kernel"
448 default y
d5028ba8 449 select STACK_VALIDATION if HAVE_STACK_VALIDATION
76b04384
DW
450 help
451 Compile kernel with the retpoline compiler options to guard against
452 kernel-to-user data leaks by avoiding speculative indirect
453 branches. Requires a compiler with -mindirect-branch=thunk-extern
454 support for full protection. The kernel may run slower.
455
e6d42931
JW
456config X86_CPU_RESCTRL
457 bool "x86 CPU resource control support"
6fe07ce3 458 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 459 select KERNFS
e79f15a4 460 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 461 help
e6d42931 462 Enable x86 CPU resource control support.
6fe07ce3
BM
463
464 Provide support for the allocation and monitoring of system resources
465 usage by the CPU.
466
467 Intel calls this Intel Resource Director Technology
468 (Intel(R) RDT). More information about RDT can be found in the
469 Intel x86 Architecture Software Developer Manual.
470
471 AMD calls this AMD Platform Quality of Service (AMD QoS).
472 More information about AMD QoS can be found in the AMD64 Technology
473 Platform Quality of Service Extensions manual.
78e99b4a
FY
474
475 Say N if unsure.
476
8425091f 477if X86_32
a0d0bb4d
RD
478config X86_BIGSMP
479 bool "Support for big SMP systems with more than 8 CPUs"
480 depends on SMP
481 ---help---
e133f6ea 482 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 483
c5c606d9
RT
484config X86_EXTENDED_PLATFORM
485 bool "Support for extended (non-PC) x86 platforms"
486 default y
8f9ca475 487 ---help---
06ac8346
IM
488 If you disable this option then the kernel will only support
489 standard PC platforms. (which covers the vast majority of
490 systems out there.)
491
8425091f
RT
492 If you enable this option then you'll be able to select support
493 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 494 Goldfish (Android emulator)
8425091f 495 AMD Elan
8425091f
RT
496 RDC R-321x SoC
497 SGI 320/540 (Visual Workstation)
83125a3a 498 STA2X11-based (e.g. Northville)
3f4110a4 499 Moorestown MID devices
06ac8346
IM
500
501 If you have one of these systems, or if you want to build a
502 generic distribution kernel, say Y here - otherwise say N.
8425091f 503endif
06ac8346 504
8425091f
RT
505if X86_64
506config X86_EXTENDED_PLATFORM
507 bool "Support for extended (non-PC) x86 platforms"
508 default y
509 ---help---
510 If you disable this option then the kernel will only support
511 standard PC platforms. (which covers the vast majority of
512 systems out there.)
513
514 If you enable this option then you'll be able to select support
515 for the following (non-PC) 64 bit x86 platforms:
44b111b5 516 Numascale NumaChip
8425091f
RT
517 ScaleMP vSMP
518 SGI Ultraviolet
519
520 If you have one of these systems, or if you want to build a
521 generic distribution kernel, say Y here - otherwise say N.
522endif
c5c606d9
RT
523# This is an alphabetically sorted list of 64 bit extended platforms
524# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
525config X86_NUMACHIP
526 bool "Numascale NumaChip"
527 depends on X86_64
528 depends on X86_EXTENDED_PLATFORM
529 depends on NUMA
530 depends on SMP
531 depends on X86_X2APIC
f9726bfd 532 depends on PCI_MMCONFIG
44b111b5
SP
533 ---help---
534 Adds support for Numascale NumaChip large-SMP systems. Needed to
535 enable more than ~168 cores.
536 If you don't have one of these, you should say N here.
506f1d07 537
c5c606d9
RT
538config X86_VSMP
539 bool "ScaleMP vSMP"
6276a074 540 select HYPERVISOR_GUEST
c5c606d9
RT
541 select PARAVIRT
542 depends on X86_64 && PCI
543 depends on X86_EXTENDED_PLATFORM
ead91d4b 544 depends on SMP
8f9ca475 545 ---help---
c5c606d9
RT
546 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
547 supposed to run on these EM64T-based machines. Only choose this option
548 if you have one of these machines.
5e3a77e9 549
03b48632
NP
550config X86_UV
551 bool "SGI Ultraviolet"
552 depends on X86_64
c5c606d9 553 depends on X86_EXTENDED_PLATFORM
54c28d29 554 depends on NUMA
1ecb4ae5 555 depends on EFI
9d6c26e7 556 depends on X86_X2APIC
1222e564 557 depends on PCI
8f9ca475 558 ---help---
03b48632
NP
559 This option is needed in order to support SGI Ultraviolet systems.
560 If you don't have one of these, you should say N here.
561
c5c606d9
RT
562# Following is an alphabetically sorted list of 32 bit extended platforms
563# Please maintain the alphabetic order if and when there are additions
506f1d07 564
ddd70cf9 565config X86_GOLDFISH
b03b016f
KK
566 bool "Goldfish (Virtual Platform)"
567 depends on X86_EXTENDED_PLATFORM
568 ---help---
ddd70cf9
JN
569 Enable support for the Goldfish virtual platform used primarily
570 for Android development. Unless you are building for the Android
571 Goldfish emulator say N here.
572
c751e17b
TG
573config X86_INTEL_CE
574 bool "CE4100 TV platform"
575 depends on PCI
576 depends on PCI_GODIRECT
6084a6e2 577 depends on X86_IO_APIC
c751e17b
TG
578 depends on X86_32
579 depends on X86_EXTENDED_PLATFORM
37bc9f50 580 select X86_REBOOTFIXUPS
da6b737b
SAS
581 select OF
582 select OF_EARLY_FLATTREE
c751e17b
TG
583 ---help---
584 Select for the Intel CE media processor (CE4100) SOC.
585 This option compiles in support for the CE4100 SOC for settop
586 boxes and media devices.
587
4cb9b00f 588config X86_INTEL_MID
43605ef1 589 bool "Intel MID platform support"
43605ef1 590 depends on X86_EXTENDED_PLATFORM
edc6bc78 591 depends on X86_PLATFORM_DEVICES
1ea7c673 592 depends on PCI
3fda5bb4 593 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 594 depends on X86_IO_APIC
7c9c3a1e 595 select SFI
4cb9b00f 596 select I2C
7c9c3a1e 597 select DW_APB_TIMER
1ea7c673 598 select APB_TIMER
54b34aa0 599 select INTEL_SCU_PCI
15a713df 600 select MFD_INTEL_MSIC
1ea7c673 601 ---help---
4cb9b00f
DC
602 Select to build a kernel capable of supporting Intel MID (Mobile
603 Internet Device) platform systems which do not have the PCI legacy
604 interfaces. If you are building for a PC class system say N here.
1ea7c673 605
4cb9b00f
DC
606 Intel MID platforms are based on an Intel processor and chipset which
607 consume less power than most of the x86 derivatives.
43605ef1 608
8bbc2a13
BD
609config X86_INTEL_QUARK
610 bool "Intel Quark platform support"
611 depends on X86_32
612 depends on X86_EXTENDED_PLATFORM
613 depends on X86_PLATFORM_DEVICES
614 depends on X86_TSC
615 depends on PCI
616 depends on PCI_GOANY
617 depends on X86_IO_APIC
618 select IOSF_MBI
619 select INTEL_IMR
9ab6eb51 620 select COMMON_CLK
8bbc2a13
BD
621 ---help---
622 Select to include support for Quark X1000 SoC.
623 Say Y here if you have a Quark based system such as the Arduino
624 compatible Intel Galileo.
625
3d48aab1
MW
626config X86_INTEL_LPSS
627 bool "Intel Low Power Subsystem Support"
5962dd22 628 depends on X86 && ACPI && PCI
3d48aab1 629 select COMMON_CLK
0f531431 630 select PINCTRL
eebb3e8d 631 select IOSF_MBI
3d48aab1
MW
632 ---help---
633 Select to build support for Intel Low Power Subsystem such as
634 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
635 things like clock tree (common clock framework) and pincontrol
636 which are needed by the LPSS peripheral drivers.
3d48aab1 637
92082a88
KX
638config X86_AMD_PLATFORM_DEVICE
639 bool "AMD ACPI2Platform devices support"
640 depends on ACPI
641 select COMMON_CLK
642 select PINCTRL
643 ---help---
644 Select to interpret AMD specific ACPI device to platform device
645 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
646 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
647 implemented under PINCTRL subsystem.
648
ced3ce76
DB
649config IOSF_MBI
650 tristate "Intel SoC IOSF Sideband support for SoC platforms"
651 depends on PCI
652 ---help---
653 This option enables sideband register access support for Intel SoC
654 platforms. On these platforms the IOSF sideband is used in lieu of
655 MSR's for some register accesses, mostly but not limited to thermal
656 and power. Drivers may query the availability of this device to
657 determine if they need the sideband in order to work on these
658 platforms. The sideband is available on the following SoC products.
659 This list is not meant to be exclusive.
660 - BayTrail
661 - Braswell
662 - Quark
663
664 You should say Y if you are running a kernel on one of these SoC's.
665
ed2226bd
DB
666config IOSF_MBI_DEBUG
667 bool "Enable IOSF sideband access through debugfs"
668 depends on IOSF_MBI && DEBUG_FS
669 ---help---
670 Select this option to expose the IOSF sideband access registers (MCR,
671 MDR, MCRX) through debugfs to write and read register information from
672 different units on the SoC. This is most useful for obtaining device
673 state information for debug and analysis. As this is a general access
674 mechanism, users of this option would have specific knowledge of the
675 device they want to access.
676
677 If you don't require the option or are in doubt, say N.
678
c5c606d9
RT
679config X86_RDC321X
680 bool "RDC R-321x SoC"
506f1d07 681 depends on X86_32
c5c606d9
RT
682 depends on X86_EXTENDED_PLATFORM
683 select M486
684 select X86_REBOOTFIXUPS
685 ---help---
686 This option is needed for RDC R-321x system-on-chip, also known
687 as R-8610-(G).
688 If you don't have one of these chips, you should say N here.
689
e0c7ae37 690config X86_32_NON_STANDARD
9c398017
IM
691 bool "Support non-standard 32-bit SMP architectures"
692 depends on X86_32 && SMP
c5c606d9 693 depends on X86_EXTENDED_PLATFORM
8f9ca475 694 ---help---
b5660ba7
PA
695 This option compiles in the bigsmp and STA2X11 default
696 subarchitectures. It is intended for a generic binary
697 kernel. If you select them all, kernel will probe it one by
698 one and will fallback to default.
d49c4288 699
c5c606d9 700# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 701
d949f36f 702config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 703 def_bool y
d949f36f
LT
704 # MCE code calls memory_failure():
705 depends on X86_MCE
706 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
707 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
708 depends on X86_64 || !SPARSEMEM
709 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 710
83125a3a
AR
711config STA2X11
712 bool "STA2X11 Companion Chip Support"
713 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
714 select SWIOTLB
715 select MFD_STA2X11
0145071b 716 select GPIOLIB
83125a3a
AR
717 ---help---
718 This adds support for boards based on the STA2X11 IO-Hub,
719 a.k.a. "ConneXt". The chip is used in place of the standard
720 PC chipset, so all "standard" peripherals are missing. If this
721 option is selected the kernel will still be able to boot on
722 standard PC machines.
723
82148d1d
S
724config X86_32_IRIS
725 tristate "Eurobraille/Iris poweroff module"
726 depends on X86_32
727 ---help---
728 The Iris machines from EuroBraille do not have APM or ACPI support
729 to shut themselves down properly. A special I/O sequence is
730 needed to do so, which is what this module does at
731 kernel shutdown.
732
733 This is only for Iris machines from EuroBraille.
734
735 If unused, say N.
736
ae1e9130 737config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
738 def_bool y
739 prompt "Single-depth WCHAN output"
a87d0914 740 depends on X86
8f9ca475 741 ---help---
506f1d07
SR
742 Calculate simpler /proc/<PID>/wchan values. If this option
743 is disabled then wchan values will recurse back to the
744 caller function. This provides more accurate wchan values,
745 at the expense of slightly more scheduling overhead.
746
747 If in doubt, say "Y".
748
6276a074
BP
749menuconfig HYPERVISOR_GUEST
750 bool "Linux guest support"
8f9ca475 751 ---help---
6276a074
BP
752 Say Y here to enable options for running Linux under various hyper-
753 visors. This option enables basic hypervisor detection and platform
754 setup.
506f1d07 755
6276a074
BP
756 If you say N, all options in this submenu will be skipped and
757 disabled, and Linux guest support won't be built in.
506f1d07 758
6276a074 759if HYPERVISOR_GUEST
506f1d07 760
e61bd94a
EPH
761config PARAVIRT
762 bool "Enable paravirtualization code"
8f9ca475 763 ---help---
e61bd94a
EPH
764 This changes the kernel so it can modify itself when it is run
765 under a hypervisor, potentially improving performance significantly
766 over full virtualization. However, when run without a hypervisor
767 the kernel is theoretically slower and slightly larger.
768
c00a280a
JG
769config PARAVIRT_XXL
770 bool
771
6276a074
BP
772config PARAVIRT_DEBUG
773 bool "paravirt-ops debugging"
774 depends on PARAVIRT && DEBUG_KERNEL
775 ---help---
776 Enable to debug paravirt_ops internals. Specifically, BUG if
777 a paravirt_op is missing when it is called.
778
b4ecc126
JF
779config PARAVIRT_SPINLOCKS
780 bool "Paravirtualization layer for spinlocks"
6ea30386 781 depends on PARAVIRT && SMP
b4ecc126
JF
782 ---help---
783 Paravirtualized spinlocks allow a pvops backend to replace the
784 spinlock implementation with something virtualization-friendly
785 (for example, block the virtual CPU rather than spinning).
786
4c4e4f61
R
787 It has a minimal impact on native kernels and gives a nice performance
788 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 789
4c4e4f61 790 If you are unsure how to answer this question, answer Y.
b4ecc126 791
ecca2502
ZY
792config X86_HV_CALLBACK_VECTOR
793 def_bool n
794
6276a074 795source "arch/x86/xen/Kconfig"
7af192c9 796
6276a074
BP
797config KVM_GUEST
798 bool "KVM Guest support (including kvmclock)"
799 depends on PARAVIRT
800 select PARAVIRT_CLOCK
a1c4423b 801 select ARCH_CPUIDLE_HALTPOLL
6276a074 802 default y
8f9ca475 803 ---help---
6276a074
BP
804 This option enables various optimizations for running under the KVM
805 hypervisor. It includes a paravirtualized clock, so that instead
806 of relying on a PIT (or probably other) emulation by the
807 underlying device model, the host provides the guest with
808 timing infrastructure such as time of day, and system time
506f1d07 809
a1c4423b 810config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
811 def_bool n
812 prompt "Disable host haltpoll when loading haltpoll driver"
813 help
a1c4423b
MT
814 If virtualized under KVM, disable host haltpoll.
815
7733607f
MW
816config PVH
817 bool "Support for running PVH guests"
818 ---help---
819 This option enables the PVH entry point for guest virtual machines
820 as specified in the x86/HVM direct boot ABI.
821
1e20eb85
SV
822config KVM_DEBUG_FS
823 bool "Enable debug information for KVM Guests in debugfs"
824 depends on KVM_GUEST && DEBUG_FS
1e20eb85
SV
825 ---help---
826 This option enables collection of various statistics for KVM guest.
827 Statistics are displayed in debugfs filesystem. Enabling this option
828 may incur significant overhead.
829
6276a074
BP
830config PARAVIRT_TIME_ACCOUNTING
831 bool "Paravirtual steal time accounting"
832 depends on PARAVIRT
8f9ca475 833 ---help---
6276a074
BP
834 Select this option to enable fine granularity task steal time
835 accounting. Time spent executing other tasks in parallel with
836 the current vCPU is discounted from the vCPU power. To account for
837 that, there can be a small performance impact.
838
839 If in doubt, say N here.
840
841config PARAVIRT_CLOCK
842 bool
97349135 843
4a362601
JK
844config JAILHOUSE_GUEST
845 bool "Jailhouse non-root cell support"
abde587b 846 depends on X86_64 && PCI
87e65d05 847 select X86_PM_TIMER
4a362601
JK
848 ---help---
849 This option allows to run Linux as guest in a Jailhouse non-root
850 cell. You can leave this option disabled if you only want to start
851 Jailhouse and run Linux afterwards in the root cell.
852
ec7972c9
ZY
853config ACRN_GUEST
854 bool "ACRN Guest support"
855 depends on X86_64
498ad393 856 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
857 help
858 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
859 a flexible, lightweight reference open-source hypervisor, built with
860 real-time and safety-criticality in mind. It is built for embedded
861 IOT with small footprint and real-time features. More details can be
862 found in https://projectacrn.org/.
863
6276a074 864endif #HYPERVISOR_GUEST
97349135 865
506f1d07
SR
866source "arch/x86/Kconfig.cpu"
867
868config HPET_TIMER
3c2362e6 869 def_bool X86_64
506f1d07 870 prompt "HPET Timer Support" if X86_32
8f9ca475
IM
871 ---help---
872 Use the IA-PC HPET (High Precision Event Timer) to manage
873 time in preference to the PIT and RTC, if a HPET is
874 present.
875 HPET is the next generation timer replacing legacy 8254s.
876 The HPET provides a stable time base on SMP
877 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
878 as it is off-chip. The interface used is documented
879 in the HPET spec, revision 1.
506f1d07 880
8f9ca475
IM
881 You can safely choose Y here. However, HPET will only be
882 activated if the platform and the BIOS support this feature.
883 Otherwise the 8254 will be used for timing services.
506f1d07 884
8f9ca475 885 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
886
887config HPET_EMULATE_RTC
3c2362e6 888 def_bool y
9d8af78b 889 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 890
bb24c471 891config APB_TIMER
b03b016f
KK
892 def_bool y if X86_INTEL_MID
893 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
894 select DW_APB_TIMER
895 depends on X86_INTEL_MID && SFI
896 help
897 APB timer is the replacement for 8254, HPET on X86 MID platforms.
898 The APBT provides a stable time base on SMP
899 systems, unlike the TSC, but it is more expensive to access,
900 as it is off-chip. APB timers are always running regardless of CPU
901 C states, they are used as per CPU clockevent device when possible.
bb24c471 902
6a108a14 903# Mark as expert because too many people got it wrong.
506f1d07 904# The code disables itself when not needed.
7ae9392c
TP
905config DMI
906 default y
cf074402 907 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 908 bool "Enable DMI scanning" if EXPERT
8f9ca475 909 ---help---
7ae9392c
TP
910 Enabled scanning of DMI to identify machine quirks. Say Y
911 here unless you have verified that your setup is not
912 affected by entries in the DMI blacklist. Required by PNP
913 BIOS code.
914
506f1d07 915config GART_IOMMU
38901f1c 916 bool "Old AMD GART IOMMU support"
a4ce5a48 917 select IOMMU_HELPER
506f1d07 918 select SWIOTLB
23ac4ae8 919 depends on X86_64 && PCI && AMD_NB
8f9ca475 920 ---help---
ced3c42c
IM
921 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
922 GART based hardware IOMMUs.
923
924 The GART supports full DMA access for devices with 32-bit access
925 limitations, on systems with more than 3 GB. This is usually needed
926 for USB, sound, many IDE/SATA chipsets and some other devices.
927
928 Newer systems typically have a modern AMD IOMMU, supported via
929 the CONFIG_AMD_IOMMU=y config option.
930
931 In normal configurations this driver is only active when needed:
932 there's more than 3 GB of memory and the system contains a
933 32-bit limited device.
934
935 If unsure, say Y.
506f1d07 936
1184dc2f 937config MAXSMP
ddb0c5a6 938 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 939 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 940 select CPUMASK_OFFSTACK
8f9ca475 941 ---help---
ddb0c5a6 942 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 943 If unsure, say N.
506f1d07 944
aec6487e
IM
945#
946# The maximum number of CPUs supported:
947#
948# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
949# and which can be configured interactively in the
950# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
951#
952# The ranges are different on 32-bit and 64-bit kernels, depending on
953# hardware capabilities and scalability features of the kernel.
954#
955# ( If MAXSMP is enabled we just use the highest possible value and disable
956# interactive configuration. )
957#
958
959config NR_CPUS_RANGE_BEGIN
a0d0bb4d 960 int
aec6487e
IM
961 default NR_CPUS_RANGE_END if MAXSMP
962 default 1 if !SMP
963 default 2
a0d0bb4d 964
aec6487e 965config NR_CPUS_RANGE_END
a0d0bb4d 966 int
aec6487e
IM
967 depends on X86_32
968 default 64 if SMP && X86_BIGSMP
969 default 8 if SMP && !X86_BIGSMP
970 default 1 if !SMP
a0d0bb4d 971
aec6487e 972config NR_CPUS_RANGE_END
a0d0bb4d 973 int
aec6487e 974 depends on X86_64
1edae1ae
SW
975 default 8192 if SMP && CPUMASK_OFFSTACK
976 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 977 default 1 if !SMP
a0d0bb4d 978
aec6487e 979config NR_CPUS_DEFAULT
a0d0bb4d
RD
980 int
981 depends on X86_32
aec6487e
IM
982 default 32 if X86_BIGSMP
983 default 8 if SMP
984 default 1 if !SMP
a0d0bb4d 985
aec6487e 986config NR_CPUS_DEFAULT
a0d0bb4d
RD
987 int
988 depends on X86_64
aec6487e
IM
989 default 8192 if MAXSMP
990 default 64 if SMP
991 default 1 if !SMP
a0d0bb4d 992
506f1d07 993config NR_CPUS
36f5101a 994 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
995 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
996 default NR_CPUS_DEFAULT
8f9ca475 997 ---help---
506f1d07 998 This allows you to specify the maximum number of CPUs which this
bb61ccc7 999 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1000 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1001 minimum value which makes sense is 2.
1002
aec6487e
IM
1003 This is purely to save memory: each supported CPU adds about 8KB
1004 to the kernel image.
506f1d07
SR
1005
1006config SCHED_SMT
dbe73364 1007 def_bool y if SMP
506f1d07
SR
1008
1009config SCHED_MC
3c2362e6
HH
1010 def_bool y
1011 prompt "Multi-core scheduler support"
c8e56d20 1012 depends on SMP
8f9ca475 1013 ---help---
506f1d07
SR
1014 Multi-core scheduler support improves the CPU scheduler's decision
1015 making when dealing with multi-core CPU chips at a cost of slightly
1016 increased overhead in some places. If unsure say N here.
1017
de966cf4
TC
1018config SCHED_MC_PRIO
1019 bool "CPU core priorities scheduler support"
0a21fc12
IM
1020 depends on SCHED_MC && CPU_SUP_INTEL
1021 select X86_INTEL_PSTATE
1022 select CPU_FREQ
de966cf4 1023 default y
5e76b2ab 1024 ---help---
0a21fc12
IM
1025 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1026 core ordering determined at manufacturing time, which allows
1027 certain cores to reach higher turbo frequencies (when running
1028 single threaded workloads) than others.
de966cf4 1029
0a21fc12
IM
1030 Enabling this kernel feature teaches the scheduler about
1031 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1032 scheduler's CPU selection logic accordingly, so that higher
1033 overall system performance can be achieved.
de966cf4 1034
0a21fc12 1035 This feature will have no effect on CPUs without this feature.
de966cf4 1036
0a21fc12 1037 If unsure say Y here.
5e76b2ab 1038
30b8b006 1039config UP_LATE_INIT
b03b016f
KK
1040 def_bool y
1041 depends on !SMP && X86_LOCAL_APIC
30b8b006 1042
506f1d07 1043config X86_UP_APIC
50849eef
JB
1044 bool "Local APIC support on uniprocessors" if !PCI_MSI
1045 default PCI_MSI
38a1dfda 1046 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
8f9ca475 1047 ---help---
506f1d07
SR
1048 A local APIC (Advanced Programmable Interrupt Controller) is an
1049 integrated interrupt controller in the CPU. If you have a single-CPU
1050 system which has a processor with a local APIC, you can say Y here to
1051 enable and use it. If you say Y here even though your machine doesn't
1052 have a local APIC, then the kernel will still run with no slowdown at
1053 all. The local APIC supports CPU-generated self-interrupts (timer,
1054 performance counters), and the NMI watchdog which detects hard
1055 lockups.
1056
1057config X86_UP_IOAPIC
1058 bool "IO-APIC support on uniprocessors"
1059 depends on X86_UP_APIC
8f9ca475 1060 ---help---
506f1d07
SR
1061 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1062 SMP-capable replacement for PC-style interrupt controllers. Most
1063 SMP systems and many recent uniprocessor systems have one.
1064
1065 If you have a single-CPU system with an IO-APIC, you can say Y here
1066 to use it. If you say Y here even though your machine doesn't have
1067 an IO-APIC, then the kernel will still run with no slowdown at all.
1068
1069config X86_LOCAL_APIC
3c2362e6 1070 def_bool y
0dbc6078 1071 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1072 select IRQ_DOMAIN_HIERARCHY
52f518a3 1073 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
506f1d07
SR
1074
1075config X86_IO_APIC
b1da1e71
JB
1076 def_bool y
1077 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1078
41b9eb26
SA
1079config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1080 bool "Reroute for broken boot IRQs"
41b9eb26 1081 depends on X86_IO_APIC
8f9ca475 1082 ---help---
41b9eb26
SA
1083 This option enables a workaround that fixes a source of
1084 spurious interrupts. This is recommended when threaded
1085 interrupt handling is used on systems where the generation of
1086 superfluous "boot interrupts" cannot be disabled.
1087
1088 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1089 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1090 kernel does during interrupt handling). On chipsets where this
1091 boot IRQ generation cannot be disabled, this workaround keeps
1092 the original IRQ line masked so that only the equivalent "boot
1093 IRQ" is delivered to the CPUs. The workaround also tells the
1094 kernel to set up the IRQ handler on the boot IRQ line. In this
1095 way only one interrupt is delivered to the kernel. Otherwise
1096 the spurious second interrupt may cause the kernel to bring
1097 down (vital) interrupt lines.
1098
1099 Only affects "broken" chipsets. Interrupt sharing may be
1100 increased on these systems.
1101
506f1d07 1102config X86_MCE
bab9bc65 1103 bool "Machine Check / overheating reporting"
648ed940 1104 select GENERIC_ALLOCATOR
e57dbaf7 1105 default y
506f1d07 1106 ---help---
bab9bc65
AK
1107 Machine Check support allows the processor to notify the
1108 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1109 The action the kernel takes depends on the severity of the problem,
bab9bc65 1110 ranging from warning messages to halting the machine.
4efc0670 1111
5de97c9f
TL
1112config X86_MCELOG_LEGACY
1113 bool "Support for deprecated /dev/mcelog character device"
1114 depends on X86_MCE
1115 ---help---
1116 Enable support for /dev/mcelog which is needed by the old mcelog
1117 userspace logging daemon. Consider switching to the new generation
1118 rasdaemon solution.
1119
506f1d07 1120config X86_MCE_INTEL
3c2362e6
HH
1121 def_bool y
1122 prompt "Intel MCE features"
c1ebf835 1123 depends on X86_MCE && X86_LOCAL_APIC
8f9ca475 1124 ---help---
506f1d07
SR
1125 Additional support for intel specific MCE features such as
1126 the thermal monitor.
1127
1128config X86_MCE_AMD
3c2362e6
HH
1129 def_bool y
1130 prompt "AMD MCE features"
f5382de9 1131 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
8f9ca475 1132 ---help---
506f1d07
SR
1133 Additional support for AMD specific MCE features such as
1134 the DRAM Error Threshold.
1135
4efc0670 1136config X86_ANCIENT_MCE
6fc108a0 1137 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1138 depends on X86_32 && X86_MCE
cd13adcc
HS
1139 ---help---
1140 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1141 systems. These typically need to be enabled explicitly on the command
cd13adcc 1142 line.
4efc0670 1143
b2762686
AK
1144config X86_MCE_THRESHOLD
1145 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1146 def_bool y
b2762686 1147
ea149b36 1148config X86_MCE_INJECT
bc8e80d5 1149 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36
AK
1150 tristate "Machine check injector support"
1151 ---help---
1152 Provide support for injecting machine checks for testing purposes.
1153 If you don't know what a machine check is and you don't do kernel
1154 QA it is safe to say n.
1155
4efc0670
AK
1156config X86_THERMAL_VECTOR
1157 def_bool y
5bb38adc 1158 depends on X86_MCE_INTEL
4efc0670 1159
07dc900e 1160source "arch/x86/events/Kconfig"
e633c65a 1161
5aef51c3 1162config X86_LEGACY_VM86
1e642812 1163 bool "Legacy VM86 support"
506f1d07 1164 depends on X86_32
8f9ca475 1165 ---help---
5aef51c3
AL
1166 This option allows user programs to put the CPU into V8086
1167 mode, which is an 80286-era approximation of 16-bit real mode.
1168
1169 Some very old versions of X and/or vbetool require this option
1170 for user mode setting. Similarly, DOSEMU will use it if
1171 available to accelerate real mode DOS programs. However, any
1172 recent version of DOSEMU, X, or vbetool should be fully
1173 functional even without kernel VM86 support, as they will all
1e642812
IM
1174 fall back to software emulation. Nevertheless, if you are using
1175 a 16-bit DOS program where 16-bit performance matters, vm86
1176 mode might be faster than emulation and you might want to
1177 enable this option.
5aef51c3 1178
1e642812
IM
1179 Note that any app that works on a 64-bit kernel is unlikely to
1180 need this option, as 64-bit kernels don't, and can't, support
1181 V8086 mode. This option is also unrelated to 16-bit protected
1182 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1183
1e642812
IM
1184 Enabling this option increases the complexity of the kernel
1185 and slows down exception handling a tiny bit.
5aef51c3 1186
1e642812 1187 If unsure, say N here.
5aef51c3
AL
1188
1189config VM86
b03b016f
KK
1190 bool
1191 default X86_LEGACY_VM86
34273f41
PA
1192
1193config X86_16BIT
1194 bool "Enable support for 16-bit segments" if EXPERT
1195 default y
a5b9e5a2 1196 depends on MODIFY_LDT_SYSCALL
34273f41
PA
1197 ---help---
1198 This option is required by programs like Wine to run 16-bit
1199 protected mode legacy code on x86 processors. Disabling
1200 this option saves about 300 bytes on i386, or around 6K text
1201 plus 16K runtime memory on x86-64,
1202
1203config X86_ESPFIX32
1204 def_bool y
1205 depends on X86_16BIT && X86_32
506f1d07 1206
197725de
PA
1207config X86_ESPFIX64
1208 def_bool y
34273f41 1209 depends on X86_16BIT && X86_64
506f1d07 1210
1ad83c85 1211config X86_VSYSCALL_EMULATION
b03b016f
KK
1212 bool "Enable vsyscall emulation" if EXPERT
1213 default y
1214 depends on X86_64
1215 ---help---
1ad83c85
AL
1216 This enables emulation of the legacy vsyscall page. Disabling
1217 it is roughly equivalent to booting with vsyscall=none, except
1218 that it will also disable the helpful warning if a program
1219 tries to use a vsyscall. With this option set to N, offending
1220 programs will just segfault, citing addresses of the form
1221 0xffffffffff600?00.
1222
1223 This option is required by many programs built before 2013, and
1224 care should be used even with newer programs if set to N.
1225
1226 Disabling this option saves about 7K of kernel size and
1227 possibly 4K of additional runtime pagetable memory.
1228
111e7b15
TG
1229config X86_IOPL_IOPERM
1230 bool "IOPERM and IOPL Emulation"
a24ca997 1231 default y
c8137ace 1232 ---help---
111e7b15
TG
1233 This enables the ioperm() and iopl() syscalls which are necessary
1234 for legacy applications.
1235
c8137ace
TG
1236 Legacy IOPL support is an overbroad mechanism which allows user
1237 space aside of accessing all 65536 I/O ports also to disable
1238 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1239 capabilities and permission from potentially active security
1240 modules.
1241
1242 The emulation restricts the functionality of the syscall to
1243 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1244 ability to disable interrupts from user space which would be
1245 granted if the hardware IOPL mechanism would be used.
c8137ace 1246
506f1d07
SR
1247config TOSHIBA
1248 tristate "Toshiba Laptop support"
1249 depends on X86_32
1250 ---help---
1251 This adds a driver to safely access the System Management Mode of
1252 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1253 not work on models with a Phoenix BIOS. The System Management Mode
1254 is used to set the BIOS and power saving options on Toshiba portables.
1255
1256 For information on utilities to make use of this driver see the
1257 Toshiba Linux utilities web site at:
1258 <http://www.buzzard.org.uk/toshiba/>.
1259
1260 Say Y if you intend to run this kernel on a Toshiba portable.
1261 Say N otherwise.
1262
1263config I8K
039ae585 1264 tristate "Dell i8k legacy laptop support"
949a9d70 1265 select HWMON
039ae585 1266 select SENSORS_DELL_SMM
506f1d07 1267 ---help---
039ae585
PR
1268 This option enables legacy /proc/i8k userspace interface in hwmon
1269 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1270 temperature and allows controlling fan speeds of Dell laptops via
1271 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1272 it reports also power and hotkey status. For fan speed control is
1273 needed userspace package i8kutils.
1274
1275 Say Y if you intend to run this kernel on old Dell laptops or want to
1276 use userspace package i8kutils.
506f1d07
SR
1277 Say N otherwise.
1278
1279config X86_REBOOTFIXUPS
9ba16087
JB
1280 bool "Enable X86 board specific fixups for reboot"
1281 depends on X86_32
506f1d07
SR
1282 ---help---
1283 This enables chipset and/or board specific fixups to be done
1284 in order to get reboot to work correctly. This is only needed on
1285 some combinations of hardware and BIOS. The symptom, for which
1286 this config is intended, is when reboot ends with a stalled/hung
1287 system.
1288
1289 Currently, the only fixup is for the Geode machines using
5e3a77e9 1290 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1291
1292 Say Y if you want to enable the fixup. Currently, it's safe to
1293 enable this option even if you don't need it.
1294 Say N otherwise.
1295
1296config MICROCODE
9a2bc335
BP
1297 bool "CPU microcode loading support"
1298 default y
80030e3d 1299 depends on CPU_SUP_AMD || CPU_SUP_INTEL
506f1d07
SR
1300 select FW_LOADER
1301 ---help---
1302 If you say Y here, you will be able to update the microcode on
5f9c01aa
BP
1303 Intel and AMD processors. The Intel support is for the IA32 family,
1304 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1305 AMD support is for families 0x10 and later. You will obviously need
1306 the actual microcode binary data itself which is not shipped with
1307 the Linux kernel.
1308
1309 The preferred method to load microcode from a detached initrd is described
cb1aaebe 1310 in Documentation/x86/microcode.rst. For that you need to enable
5f9c01aa
BP
1311 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1312 initrd for microcode blobs.
1313
c508c46e
BG
1314 In addition, you can build the microcode into the kernel. For that you
1315 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1316 config option.
506f1d07 1317
8d86f390 1318config MICROCODE_INTEL
e43f6e67 1319 bool "Intel microcode loading support"
8f9ca475
IM
1320 depends on MICROCODE
1321 default MICROCODE
1322 select FW_LOADER
1323 ---help---
1324 This options enables microcode patch loading support for Intel
1325 processors.
1326
b8989db9
A
1327 For the current Intel microcode data package go to
1328 <https://downloadcenter.intel.com> and search for
1329 'Linux Processor Microcode Data File'.
8d86f390 1330
80cc9f10 1331config MICROCODE_AMD
e43f6e67 1332 bool "AMD microcode loading support"
8f9ca475
IM
1333 depends on MICROCODE
1334 select FW_LOADER
1335 ---help---
1336 If you select this option, microcode patch loading support for AMD
1337 processors will be enabled.
80cc9f10 1338
8f9ca475 1339config MICROCODE_OLD_INTERFACE
c02f48e0
BP
1340 bool "Ancient loading interface (DEPRECATED)"
1341 default n
506f1d07 1342 depends on MICROCODE
c02f48e0
BP
1343 ---help---
1344 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1345 which was used by userspace tools like iucode_tool and microcode.ctl.
1346 It is inadequate because it runs too late to be able to properly
1347 load microcode on a machine and it needs special tools. Instead, you
1348 should've switched to the early loading method with the initrd or
cb1aaebe 1349 builtin microcode by now: Documentation/x86/microcode.rst
506f1d07
SR
1350
1351config X86_MSR
1352 tristate "/dev/cpu/*/msr - Model-specific register support"
8f9ca475 1353 ---help---
506f1d07
SR
1354 This device gives privileged processes access to the x86
1355 Model-Specific Registers (MSRs). It is a character device with
1356 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1357 MSR accesses are directed to a specific CPU on multi-processor
1358 systems.
1359
1360config X86_CPUID
1361 tristate "/dev/cpu/*/cpuid - CPU information support"
8f9ca475 1362 ---help---
506f1d07
SR
1363 This device gives processes access to the x86 CPUID instruction to
1364 be executed on a specific processor. It is a character device
1365 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1366 /dev/cpu/31/cpuid.
1367
1368choice
1369 prompt "High Memory Support"
6fc108a0 1370 default HIGHMEM4G
506f1d07
SR
1371 depends on X86_32
1372
1373config NOHIGHMEM
1374 bool "off"
506f1d07
SR
1375 ---help---
1376 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1377 However, the address space of 32-bit x86 processors is only 4
1378 Gigabytes large. That means that, if you have a large amount of
1379 physical memory, not all of it can be "permanently mapped" by the
1380 kernel. The physical memory that's not permanently mapped is called
1381 "high memory".
1382
1383 If you are compiling a kernel which will never run on a machine with
1384 more than 1 Gigabyte total physical RAM, answer "off" here (default
1385 choice and suitable for most users). This will result in a "3GB/1GB"
1386 split: 3GB are mapped so that each process sees a 3GB virtual memory
1387 space and the remaining part of the 4GB virtual memory space is used
1388 by the kernel to permanently map as much physical memory as
1389 possible.
1390
1391 If the machine has between 1 and 4 Gigabytes physical RAM, then
1392 answer "4GB" here.
1393
1394 If more than 4 Gigabytes is used then answer "64GB" here. This
1395 selection turns Intel PAE (Physical Address Extension) mode on.
1396 PAE implements 3-level paging on IA32 processors. PAE is fully
1397 supported by Linux, PAE mode is implemented on all recent Intel
1398 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1399 then the kernel will not boot on CPUs that don't support PAE!
1400
1401 The actual amount of total physical memory will either be
1402 auto detected or can be forced by using a kernel command line option
1403 such as "mem=256M". (Try "man bootparam" or see the documentation of
1404 your boot loader (lilo or loadlin) about how to pass options to the
1405 kernel at boot time.)
1406
1407 If unsure, say "off".
1408
1409config HIGHMEM4G
1410 bool "4GB"
8f9ca475 1411 ---help---
506f1d07
SR
1412 Select this if you have a 32-bit processor and between 1 and 4
1413 gigabytes of physical RAM.
1414
1415config HIGHMEM64G
1416 bool "64GB"
69b8d3fc 1417 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
506f1d07 1418 select X86_PAE
8f9ca475 1419 ---help---
506f1d07
SR
1420 Select this if you have a 32-bit processor and more than 4
1421 gigabytes of physical RAM.
1422
1423endchoice
1424
1425choice
6a108a14 1426 prompt "Memory split" if EXPERT
506f1d07
SR
1427 default VMSPLIT_3G
1428 depends on X86_32
8f9ca475 1429 ---help---
506f1d07
SR
1430 Select the desired split between kernel and user memory.
1431
1432 If the address range available to the kernel is less than the
1433 physical memory installed, the remaining memory will be available
1434 as "high memory". Accessing high memory is a little more costly
1435 than low memory, as it needs to be mapped into the kernel first.
1436 Note that increasing the kernel address space limits the range
1437 available to user programs, making the address space there
1438 tighter. Selecting anything other than the default 3G/1G split
1439 will also likely make your kernel incompatible with binary-only
1440 kernel modules.
1441
1442 If you are not absolutely sure what you are doing, leave this
1443 option alone!
1444
1445 config VMSPLIT_3G
1446 bool "3G/1G user/kernel split"
1447 config VMSPLIT_3G_OPT
1448 depends on !X86_PAE
1449 bool "3G/1G user/kernel split (for full 1G low memory)"
1450 config VMSPLIT_2G
1451 bool "2G/2G user/kernel split"
1452 config VMSPLIT_2G_OPT
1453 depends on !X86_PAE
1454 bool "2G/2G user/kernel split (for full 2G low memory)"
1455 config VMSPLIT_1G
1456 bool "1G/3G user/kernel split"
1457endchoice
1458
1459config PAGE_OFFSET
1460 hex
1461 default 0xB0000000 if VMSPLIT_3G_OPT
1462 default 0x80000000 if VMSPLIT_2G
1463 default 0x78000000 if VMSPLIT_2G_OPT
1464 default 0x40000000 if VMSPLIT_1G
1465 default 0xC0000000
1466 depends on X86_32
1467
1468config HIGHMEM
3c2362e6 1469 def_bool y
506f1d07 1470 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1471
1472config X86_PAE
9ba16087 1473 bool "PAE (Physical Address Extension) Support"
506f1d07 1474 depends on X86_32 && !HIGHMEM4G
d4a451d5 1475 select PHYS_ADDR_T_64BIT
9d99c712 1476 select SWIOTLB
8f9ca475 1477 ---help---
506f1d07
SR
1478 PAE is required for NX support, and furthermore enables
1479 larger swapspace support for non-overcommit purposes. It
1480 has the cost of more pagetable lookup overhead, and also
1481 consumes more pagetable space per process.
1482
77ef56e4
KS
1483config X86_5LEVEL
1484 bool "Enable 5-level page tables support"
18ec1eaf 1485 default y
eedb92ab 1486 select DYNAMIC_MEMORY_LAYOUT
162434e7 1487 select SPARSEMEM_VMEMMAP
77ef56e4
KS
1488 depends on X86_64
1489 ---help---
1490 5-level paging enables access to larger address space:
1491 upto 128 PiB of virtual address space and 4 PiB of
1492 physical address space.
1493
1494 It will be supported by future Intel CPUs.
1495
6657fca0
KS
1496 A kernel with the option enabled can be booted on machines that
1497 support 4- or 5-level paging.
77ef56e4 1498
cb1aaebe 1499 See Documentation/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1500 information.
1501
1502 Say N if unsure.
1503
10971ab2 1504config X86_DIRECT_GBPAGES
e5008abe 1505 def_bool y
2e1da13f 1506 depends on X86_64
8f9ca475 1507 ---help---
10971ab2
IM
1508 Certain kernel features effectively disable kernel
1509 linear 1 GB mappings (even if the CPU otherwise
1510 supports them), so don't confuse the user by printing
1511 that we have them enabled.
9e899816 1512
5c280cf6
TG
1513config X86_CPA_STATISTICS
1514 bool "Enable statistic for Change Page Attribute"
1515 depends on DEBUG_FS
1516 ---help---
b75baaf3 1517 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1518 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1519 page mappings when mapping protections are changed.
1520
7744ccdb
TL
1521config AMD_MEM_ENCRYPT
1522 bool "AMD Secure Memory Encryption (SME) support"
1523 depends on X86_64 && CPU_SUP_AMD
94d49eb3 1524 select DYNAMIC_PHYSICAL_MASK
ce9084ba 1525 select ARCH_USE_MEMREMAP_PROT
9087c375 1526 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
7744ccdb
TL
1527 ---help---
1528 Say yes to enable support for the encryption of system memory.
1529 This requires an AMD processor that supports Secure Memory
1530 Encryption (SME).
1531
1532config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1533 bool "Activate AMD Secure Memory Encryption (SME) by default"
1534 default y
1535 depends on AMD_MEM_ENCRYPT
1536 ---help---
1537 Say yes to have system memory encrypted by default if running on
1538 an AMD processor that supports Secure Memory Encryption (SME).
1539
1540 If set to Y, then the encryption of system memory can be
1541 deactivated with the mem_encrypt=off command line option.
1542
1543 If set to N, then the encryption of system memory can be
1544 activated with the mem_encrypt=on command line option.
1545
506f1d07
SR
1546# Common NUMA Features
1547config NUMA
e133f6ea 1548 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1549 depends on SMP
b5660ba7
PA
1550 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1551 default y if X86_BIGSMP
8f9ca475 1552 ---help---
e133f6ea 1553 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1554
506f1d07
SR
1555 The kernel will try to allocate memory used by a CPU on the
1556 local memory controller of the CPU and add some more
1557 NUMA awareness to the kernel.
1558
c280ea5e 1559 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1560 (or later), AMD Opteron, or EM64T NUMA.
1561
b5660ba7 1562 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1563 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1564
1565 Otherwise, you should say N.
506f1d07 1566
eec1d4fa 1567config AMD_NUMA
3c2362e6
HH
1568 def_bool y
1569 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1570 depends on X86_64 && NUMA && PCI
8f9ca475 1571 ---help---
eec1d4fa
HR
1572 Enable AMD NUMA node topology detection. You should say Y here if
1573 you have a multi processor AMD system. This uses an old method to
1574 read the NUMA configuration directly from the builtin Northbridge
1575 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1576 which also takes priority if both are compiled in.
506f1d07
SR
1577
1578config X86_64_ACPI_NUMA
3c2362e6
HH
1579 def_bool y
1580 prompt "ACPI NUMA detection"
506f1d07
SR
1581 depends on X86_64 && NUMA && ACPI && PCI
1582 select ACPI_NUMA
8f9ca475 1583 ---help---
506f1d07
SR
1584 Enable ACPI SRAT based node topology detection.
1585
6ec6e0d9
SS
1586# Some NUMA nodes have memory ranges that span
1587# other nodes. Even though a pfn is valid and
1588# between a node's start and end pfns, it may not
1589# reside on that node. See memmap_init_zone()
1590# for details.
1591config NODES_SPAN_OTHER_NODES
1592 def_bool y
1593 depends on X86_64_ACPI_NUMA
1594
506f1d07
SR
1595config NUMA_EMU
1596 bool "NUMA emulation"
1b7e03ef 1597 depends on NUMA
8f9ca475 1598 ---help---
506f1d07
SR
1599 Enable NUMA emulation. A flat machine will be split
1600 into virtual nodes when booted with "numa=fake=N", where N is the
1601 number of nodes. This is only useful for debugging.
1602
1603config NODES_SHIFT
d25e26b6 1604 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1605 range 1 10
1606 default "10" if MAXSMP
506f1d07 1607 default "6" if X86_64
506f1d07
SR
1608 default "3"
1609 depends on NEED_MULTIPLE_NODES
8f9ca475 1610 ---help---
1184dc2f 1611 Specify the maximum number of NUMA Nodes available on the target
692105b8 1612 system. Increases memory reserved to accommodate various tables.
506f1d07 1613
506f1d07
SR
1614config ARCH_FLATMEM_ENABLE
1615 def_bool y
3b16651f 1616 depends on X86_32 && !NUMA
506f1d07 1617
506f1d07
SR
1618config ARCH_SPARSEMEM_ENABLE
1619 def_bool y
6ea30386 1620 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1621 select SPARSEMEM_STATIC if X86_32
1622 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1623
3b16651f 1624config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1625 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1626
506f1d07
SR
1627config ARCH_SELECT_MEMORY_MODEL
1628 def_bool y
b263295d 1629 depends on ARCH_SPARSEMEM_ENABLE
506f1d07
SR
1630
1631config ARCH_MEMORY_PROBE
a0842b70 1632 bool "Enable sysfs memory/probe interface"
3120e25e 1633 depends on X86_64 && MEMORY_HOTPLUG
a0842b70
TK
1634 help
1635 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1636 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1637 If you are unsure how to answer this question, answer N.
506f1d07 1638
3b16651f
TH
1639config ARCH_PROC_KCORE_TEXT
1640 def_bool y
1641 depends on X86_64 && PROC_KCORE
1642
a29815a3 1643config ILLEGAL_POINTER_VALUE
b03b016f
KK
1644 hex
1645 default 0 if X86_32
1646 default 0xdead000000000000 if X86_64
a29815a3 1647
7a67832c
DW
1648config X86_PMEM_LEGACY_DEVICE
1649 bool
1650
ec776ef6 1651config X86_PMEM_LEGACY
7a67832c 1652 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1653 depends on PHYS_ADDR_T_64BIT
1654 depends on BLK_DEV
7a67832c 1655 select X86_PMEM_LEGACY_DEVICE
7b27a862 1656 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1657 select LIBNVDIMM
ec776ef6
CH
1658 help
1659 Treat memory marked using the non-standard e820 type of 12 as used
1660 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1661 The kernel will offer these regions to the 'pmem' driver so
1662 they can be used for persistent storage.
1663
1664 Say Y if unsure.
1665
506f1d07
SR
1666config HIGHPTE
1667 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1668 depends on HIGHMEM
8f9ca475 1669 ---help---
506f1d07
SR
1670 The VM uses one page table entry for each page of physical memory.
1671 For systems with a lot of RAM, this can be wasteful of precious
1672 low memory. Setting this option will put user-space page table
1673 entries in high memory.
1674
9f077871 1675config X86_CHECK_BIOS_CORRUPTION
8f9ca475
IM
1676 bool "Check for low memory corruption"
1677 ---help---
1678 Periodically check for memory corruption in low memory, which
1679 is suspected to be caused by BIOS. Even when enabled in the
1680 configuration, it is disabled at runtime. Enable it by
1681 setting "memory_corruption_check=1" on the kernel command
1682 line. By default it scans the low 64k of memory every 60
1683 seconds; see the memory_corruption_check_size and
1684 memory_corruption_check_period parameters in
8c27ceff 1685 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1686
1687 When enabled with the default parameters, this option has
1688 almost no overhead, as it reserves a relatively small amount
1689 of memory and scans it infrequently. It both detects corruption
1690 and prevents it from affecting the running system.
1691
1692 It is, however, intended as a diagnostic tool; if repeatable
1693 BIOS-originated corruption always affects the same memory,
1694 you can use memmap= to prevent the kernel from using that
1695 memory.
9f077871 1696
c885df50 1697config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1698 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1699 depends on X86_CHECK_BIOS_CORRUPTION
1700 default y
8f9ca475
IM
1701 ---help---
1702 Set whether the default state of memory_corruption_check is
1703 on or off.
c885df50 1704
9ea77bdb 1705config X86_RESERVE_LOW
d0cd7425
PA
1706 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1707 default 64
1708 range 4 640
8f9ca475 1709 ---help---
d0cd7425
PA
1710 Specify the amount of low memory to reserve for the BIOS.
1711
1712 The first page contains BIOS data structures that the kernel
1713 must not use, so that page must always be reserved.
1714
1715 By default we reserve the first 64K of physical RAM, as a
1716 number of BIOSes are known to corrupt that memory range
1717 during events such as suspend/resume or monitor cable
1718 insertion, so it must not be used by the kernel.
fc381519 1719
d0cd7425
PA
1720 You can set this to 4 if you are absolutely sure that you
1721 trust the BIOS to get all its memory reservations and usages
1722 right. If you know your BIOS have problems beyond the
1723 default 64K area, you can set this to 640 to avoid using the
1724 entire low memory range.
fc381519 1725
d0cd7425
PA
1726 If you have doubts about the BIOS (e.g. suspend/resume does
1727 not work or there's kernel crashes after certain hardware
1728 hotplug events) then you might want to enable
1729 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1730 typical corruption patterns.
fc381519 1731
d0cd7425 1732 Leave this to the default value of 64 if you are unsure.
fc381519 1733
506f1d07
SR
1734config MATH_EMULATION
1735 bool
a5b9e5a2 1736 depends on MODIFY_LDT_SYSCALL
87d6021b 1737 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
506f1d07
SR
1738 ---help---
1739 Linux can emulate a math coprocessor (used for floating point
1740 operations) if you don't have one. 486DX and Pentium processors have
1741 a math coprocessor built in, 486SX and 386 do not, unless you added
1742 a 487DX or 387, respectively. (The messages during boot time can
1743 give you some hints here ["man dmesg"].) Everyone needs either a
1744 coprocessor or this emulation.
1745
1746 If you don't have a math coprocessor, you need to say Y here; if you
1747 say Y here even though you have a coprocessor, the coprocessor will
1748 be used nevertheless. (This behavior can be changed with the kernel
1749 command line option "no387", which comes handy if your coprocessor
1750 is broken. Try "man bootparam" or see the documentation of your boot
1751 loader (lilo or loadlin) about how to pass options to the kernel at
1752 boot time.) This means that it is a good idea to say Y here if you
1753 intend to use this kernel on different machines.
1754
1755 More information about the internals of the Linux math coprocessor
1756 emulation can be found in <file:arch/x86/math-emu/README>.
1757
1758 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1759 kernel, it won't hurt.
1760
1761config MTRR
6fc108a0 1762 def_bool y
6a108a14 1763 prompt "MTRR (Memory Type Range Register) support" if EXPERT
506f1d07
SR
1764 ---help---
1765 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1766 the Memory Type Range Registers (MTRRs) may be used to control
1767 processor access to memory ranges. This is most useful if you have
1768 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1769 allows bus write transfers to be combined into a larger transfer
1770 before bursting over the PCI/AGP bus. This can increase performance
1771 of image write operations 2.5 times or more. Saying Y here creates a
1772 /proc/mtrr file which may be used to manipulate your processor's
1773 MTRRs. Typically the X server should use this.
1774
1775 This code has a reasonably generic interface so that similar
1776 control registers on other processors can be easily supported
1777 as well:
1778
1779 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1780 Registers (ARRs) which provide a similar functionality to MTRRs. For
1781 these, the ARRs are used to emulate the MTRRs.
1782 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1783 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1784 write-combining. All of these processors are supported by this code
1785 and it makes sense to say Y here if you have one of them.
1786
1787 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1788 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1789 can lead to all sorts of problems, so it's good to say Y here.
1790
1791 You can safely say Y even if your machine doesn't have MTRRs, you'll
1792 just add about 9 KB to your kernel.
1793
cb1aaebe 1794 See <file:Documentation/x86/mtrr.rst> for more information.
506f1d07 1795
95ffa243 1796config MTRR_SANITIZER
2ffb3501 1797 def_bool y
95ffa243
YL
1798 prompt "MTRR cleanup support"
1799 depends on MTRR
8f9ca475 1800 ---help---
aba3728c
TG
1801 Convert MTRR layout from continuous to discrete, so X drivers can
1802 add writeback entries.
95ffa243 1803
aba3728c 1804 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1805 The largest mtrr entry size for a continuous block can be set with
aba3728c 1806 mtrr_chunk_size.
95ffa243 1807
2ffb3501 1808 If unsure, say Y.
95ffa243
YL
1809
1810config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1811 int "MTRR cleanup enable value (0-1)"
1812 range 0 1
1813 default "0"
95ffa243 1814 depends on MTRR_SANITIZER
8f9ca475 1815 ---help---
f5098d62 1816 Enable mtrr cleanup default value
95ffa243 1817
12031a62
YL
1818config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1819 int "MTRR cleanup spare reg num (0-7)"
1820 range 0 7
1821 default "1"
1822 depends on MTRR_SANITIZER
8f9ca475 1823 ---help---
12031a62 1824 mtrr cleanup spare entries default, it can be changed via
aba3728c 1825 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1826
2e5d9c85 1827config X86_PAT
6fc108a0 1828 def_bool y
6a108a14 1829 prompt "x86 PAT support" if EXPERT
2a8a2719 1830 depends on MTRR
8f9ca475 1831 ---help---
2e5d9c85 1832 Use PAT attributes to setup page level cache control.
042b78e4 1833
2e5d9c85 1834 PATs are the modern equivalents of MTRRs and are much more
1835 flexible than MTRRs.
1836
1837 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1838 spontaneous reboots) or a non-working video driver.
2e5d9c85 1839
1840 If unsure, say Y.
1841
46cf98cd
VP
1842config ARCH_USES_PG_UNCACHED
1843 def_bool y
1844 depends on X86_PAT
1845
628c6246
PA
1846config ARCH_RANDOM
1847 def_bool y
1848 prompt "x86 architectural random number generator" if EXPERT
1849 ---help---
1850 Enable the x86 architectural RDRAND instruction
1851 (Intel Bull Mountain technology) to generate random numbers.
1852 If supported, this is a high bandwidth, cryptographically
1853 secure hardware random number generator.
1854
51ae4a2d
PA
1855config X86_SMAP
1856 def_bool y
1857 prompt "Supervisor Mode Access Prevention" if EXPERT
1858 ---help---
1859 Supervisor Mode Access Prevention (SMAP) is a security
1860 feature in newer Intel processors. There is a small
1861 performance cost if this enabled and turned on; there is
1862 also a small increase in the kernel size if this is enabled.
1863
1864 If unsure, say Y.
1865
b971880f 1866config X86_UMIP
796ebc81 1867 def_bool y
b971880f
BM
1868 prompt "User Mode Instruction Prevention" if EXPERT
1869 ---help---
1870 User Mode Instruction Prevention (UMIP) is a security feature in
1871 some x86 processors. If enabled, a general protection fault is
1872 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1873 executed in user mode. These instructions unnecessarily expose
1874 information about the hardware state.
796ebc81
RN
1875
1876 The vast majority of applications do not use these instructions.
1877 For the very few that do, software emulation is provided in
1878 specific cases in protected and virtual-8086 modes. Emulated
1879 results are dummy.
aa35f896 1880
35e97790 1881config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1882 prompt "Memory Protection Keys"
35e97790 1883 def_bool y
284244a9 1884 # Note: only available in 64-bit mode
38f3e775 1885 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1886 select ARCH_USES_HIGH_VMA_FLAGS
1887 select ARCH_HAS_PKEYS
284244a9
DH
1888 ---help---
1889 Memory Protection Keys provides a mechanism for enforcing
1890 page-based protections, but without requiring modification of the
1891 page tables when an application changes protection domains.
1892
1eecbcdc 1893 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1894
1895 If unsure, say y.
35e97790 1896
db616173
MH
1897choice
1898 prompt "TSX enable mode"
1899 depends on CPU_SUP_INTEL
1900 default X86_INTEL_TSX_MODE_OFF
1901 help
1902 Intel's TSX (Transactional Synchronization Extensions) feature
1903 allows to optimize locking protocols through lock elision which
1904 can lead to a noticeable performance boost.
1905
1906 On the other hand it has been shown that TSX can be exploited
1907 to form side channel attacks (e.g. TAA) and chances are there
1908 will be more of those attacks discovered in the future.
1909
1910 Therefore TSX is not enabled by default (aka tsx=off). An admin
1911 might override this decision by tsx=on the command line parameter.
1912 Even with TSX enabled, the kernel will attempt to enable the best
1913 possible TAA mitigation setting depending on the microcode available
1914 for the particular machine.
1915
1916 This option allows to set the default tsx mode between tsx=on, =off
1917 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1918 details.
1919
1920 Say off if not sure, auto if TSX is in use but it should be used on safe
1921 platforms or on if TSX is in use and the security aspect of tsx is not
1922 relevant.
1923
1924config X86_INTEL_TSX_MODE_OFF
1925 bool "off"
1926 help
1927 TSX is disabled if possible - equals to tsx=off command line parameter.
1928
1929config X86_INTEL_TSX_MODE_ON
1930 bool "on"
1931 help
1932 TSX is always enabled on TSX capable HW - equals the tsx=on command
1933 line parameter.
1934
1935config X86_INTEL_TSX_MODE_AUTO
1936 bool "auto"
1937 help
1938 TSX is enabled on TSX capable HW that is believed to be safe against
1939 side channel attacks- equals the tsx=auto command line parameter.
1940endchoice
1941
506f1d07 1942config EFI
9ba16087 1943 bool "EFI runtime service support"
5b83683f 1944 depends on ACPI
f6ce5002 1945 select UCS2_STRING
022ee6c5 1946 select EFI_RUNTIME_WRAPPERS
506f1d07 1947 ---help---
8f9ca475
IM
1948 This enables the kernel to use EFI runtime services that are
1949 available (such as the EFI variable services).
506f1d07 1950
8f9ca475
IM
1951 This option is only useful on systems that have EFI firmware.
1952 In addition, you should use the latest ELILO loader available
1953 at <http://elilo.sourceforge.net> in order to take advantage
1954 of EFI runtime services. However, even with this option, the
1955 resultant kernel should continue to boot on existing non-EFI
1956 platforms.
506f1d07 1957
291f3632 1958config EFI_STUB
8f24f8c2
AB
1959 bool "EFI stub support"
1960 depends on EFI && !X86_USE_3DNOW
1961 depends on $(cc-option,-mabi=ms) || X86_32
1962 select RELOCATABLE
1963 ---help---
1964 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
1965 by EFI firmware without the use of a bootloader.
1966
4f4cfa6c 1967 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1968
7d453eee
MF
1969config EFI_MIXED
1970 bool "EFI mixed-mode support"
1971 depends on EFI_STUB && X86_64
1972 ---help---
1973 Enabling this feature allows a 64-bit kernel to be booted
1974 on a 32-bit firmware, provided that your CPU supports 64-bit
1975 mode.
1976
1977 Note that it is not possible to boot a mixed-mode enabled
1978 kernel via the EFI boot stub - a bootloader that supports
1979 the EFI handover protocol must be used.
1980
1981 If unsure, say N.
1982
506f1d07 1983config SECCOMP
3c2362e6
HH
1984 def_bool y
1985 prompt "Enable seccomp to safely compute untrusted bytecode"
8f9ca475 1986 ---help---
506f1d07
SR
1987 This kernel feature is useful for number crunching applications
1988 that may need to compute untrusted bytecode during their
1989 execution. By using pipes or other transports made available to
1990 the process as file descriptors supporting the read/write
1991 syscalls, it's possible to isolate those applications in
1992 their own address space using seccomp. Once seccomp is
9c0bbee8 1993 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
506f1d07
SR
1994 and the task is only allowed to execute a few safe syscalls
1995 defined by each seccomp mode.
1996
1997 If unsure, say Y. Only embedded should say N here.
1998
8636a1f9 1999source "kernel/Kconfig.hz"
506f1d07
SR
2000
2001config KEXEC
2002 bool "kexec system call"
2965faa5 2003 select KEXEC_CORE
8f9ca475 2004 ---help---
506f1d07
SR
2005 kexec is a system call that implements the ability to shutdown your
2006 current kernel, and to start another kernel. It is like a reboot
2007 but it is independent of the system firmware. And like a reboot
2008 you can start any kernel with it, not just Linux.
2009
2010 The name comes from the similarity to the exec system call.
2011
2012 It is an ongoing process to be certain the hardware in a machine
2013 is properly shutdown, so do not be surprised if this code does not
bf220695
GU
2014 initially work for you. As of this writing the exact hardware
2015 interface is strongly in flux, so no good recommendation can be
2016 made.
506f1d07 2017
74ca317c
VG
2018config KEXEC_FILE
2019 bool "kexec file based system call"
2965faa5 2020 select KEXEC_CORE
74ca317c 2021 select BUILD_BIN2C
74ca317c
VG
2022 depends on X86_64
2023 depends on CRYPTO=y
2024 depends on CRYPTO_SHA256=y
2025 ---help---
2026 This is new version of kexec system call. This system call is
2027 file based and takes file descriptors as system call argument
2028 for kernel and initramfs as opposed to list of segments as
2029 accepted by previous system call.
2030
b799a09f
AT
2031config ARCH_HAS_KEXEC_PURGATORY
2032 def_bool KEXEC_FILE
2033
99d5cadf 2034config KEXEC_SIG
8e7d8381 2035 bool "Verify kernel signature during kexec_file_load() syscall"
74ca317c 2036 depends on KEXEC_FILE
8e7d8381 2037 ---help---
d8eb8940 2038
99d5cadf
JB
2039 This option makes the kexec_file_load() syscall check for a valid
2040 signature of the kernel image. The image can still be loaded without
2041 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2042 there's a signature that we can check, then it must be valid.
2043
2044 In addition to this option, you need to enable signature
d8eb8940
BP
2045 verification for the corresponding kernel image type being
2046 loaded in order for this to work.
8e7d8381 2047
99d5cadf
JB
2048config KEXEC_SIG_FORCE
2049 bool "Require a valid signature in kexec_file_load() syscall"
2050 depends on KEXEC_SIG
2051 ---help---
2052 This option makes kernel signature verification mandatory for
2053 the kexec_file_load() syscall.
2054
8e7d8381
VG
2055config KEXEC_BZIMAGE_VERIFY_SIG
2056 bool "Enable bzImage signature verification support"
99d5cadf 2057 depends on KEXEC_SIG
8e7d8381
VG
2058 depends on SIGNED_PE_FILE_VERIFICATION
2059 select SYSTEM_TRUSTED_KEYRING
2060 ---help---
2061 Enable bzImage signature verification support.
2062
506f1d07 2063config CRASH_DUMP
04b69447 2064 bool "kernel crash dumps"
506f1d07 2065 depends on X86_64 || (X86_32 && HIGHMEM)
8f9ca475 2066 ---help---
506f1d07
SR
2067 Generate crash dump after being started by kexec.
2068 This should be normally only set in special crash dump kernels
2069 which are loaded in the main kernel with kexec-tools into
2070 a specially reserved region and then later executed after
2071 a crash by kdump/kexec. The crash dump kernel must be compiled
2072 to a memory address not used by the main kernel or BIOS using
2073 PHYSICAL_START, or it must be built as a relocatable image
2074 (CONFIG_RELOCATABLE=y).
330d4810 2075 For more details see Documentation/admin-guide/kdump/kdump.rst
506f1d07 2076
3ab83521 2077config KEXEC_JUMP
6ea30386 2078 bool "kexec jump"
fee7b0d8 2079 depends on KEXEC && HIBERNATION
8f9ca475 2080 ---help---
89081d17
HY
2081 Jump between original kernel and kexeced kernel and invoke
2082 code in physical address mode via KEXEC
3ab83521 2083
506f1d07 2084config PHYSICAL_START
6a108a14 2085 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2086 default "0x1000000"
8f9ca475 2087 ---help---
506f1d07
SR
2088 This gives the physical address where the kernel is loaded.
2089
2090 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2091 bzImage will decompress itself to above physical address and
2092 run from there. Otherwise, bzImage will run from the address where
2093 it has been loaded by the boot loader and will ignore above physical
2094 address.
2095
2096 In normal kdump cases one does not have to set/change this option
2097 as now bzImage can be compiled as a completely relocatable image
2098 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2099 address. This option is mainly useful for the folks who don't want
2100 to use a bzImage for capturing the crash dump and want to use a
2101 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2102 to be specifically compiled to run from a specific memory area
2103 (normally a reserved region) and this option comes handy.
2104
ceefccc9
PA
2105 So if you are using bzImage for capturing the crash dump,
2106 leave the value here unchanged to 0x1000000 and set
2107 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2108 for capturing the crash dump change this value to start of
2109 the reserved region. In other words, it can be set based on
2110 the "X" value as specified in the "crashkernel=YM@XM"
2111 command line boot parameter passed to the panic-ed
330d4810 2112 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2113 for more details about crash dumps.
506f1d07
SR
2114
2115 Usage of bzImage for capturing the crash dump is recommended as
2116 one does not have to build two kernels. Same kernel can be used
2117 as production kernel and capture kernel. Above option should have
2118 gone away after relocatable bzImage support is introduced. But it
2119 is present because there are users out there who continue to use
2120 vmlinux for dump capture. This option should go away down the
2121 line.
2122
2123 Don't change this unless you know what you are doing.
2124
2125config RELOCATABLE
26717808
PA
2126 bool "Build a relocatable kernel"
2127 default y
8f9ca475 2128 ---help---
506f1d07
SR
2129 This builds a kernel image that retains relocation information
2130 so it can be loaded someplace besides the default 1MB.
2131 The relocations tend to make the kernel binary about 10% larger,
2132 but are discarded at runtime.
2133
2134 One use is for the kexec on panic case where the recovery kernel
2135 must live at a different physical address than the primary
2136 kernel.
2137
2138 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2139 it has been loaded at and the compile time physical address
8ab3820f 2140 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2141
8ab3820f 2142config RANDOMIZE_BASE
e8581e3d 2143 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2144 depends on RELOCATABLE
6807c846 2145 default y
8ab3820f 2146 ---help---
e8581e3d
BH
2147 In support of Kernel Address Space Layout Randomization (KASLR),
2148 this randomizes the physical address at which the kernel image
2149 is decompressed and the virtual address where the kernel
2150 image is mapped, as a security feature that deters exploit
2151 attempts relying on knowledge of the location of kernel
2152 code internals.
2153
ed9f007e
KC
2154 On 64-bit, the kernel physical and virtual addresses are
2155 randomized separately. The physical address will be anywhere
2156 between 16MB and the top of physical memory (up to 64TB). The
2157 virtual address will be randomized from 16MB up to 1GB (9 bits
2158 of entropy). Note that this also reduces the memory space
2159 available to kernel modules from 1.5GB to 1GB.
2160
2161 On 32-bit, the kernel physical and virtual addresses are
2162 randomized together. They will be randomized from 16MB up to
2163 512MB (8 bits of entropy).
e8581e3d
BH
2164
2165 Entropy is generated using the RDRAND instruction if it is
2166 supported. If RDTSC is supported, its value is mixed into
2167 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2168 supported, then entropy is read from the i8254 timer. The
2169 usable entropy is limited by the kernel being built using
2170 2GB addressing, and that PHYSICAL_ALIGN must be at a
2171 minimum of 2MB. As a result, only 10 bits of entropy are
2172 theoretically possible, but the implementations are further
2173 limited due to memory layouts.
e8581e3d 2174
6807c846 2175 If unsure, say Y.
8ab3820f
KC
2176
2177# Relocation on x86 needs some additional build support
845adf72
PA
2178config X86_NEED_RELOCS
2179 def_bool y
8ab3820f 2180 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2181
506f1d07 2182config PHYSICAL_ALIGN
a0215061 2183 hex "Alignment value to which kernel should be aligned"
8ab3820f 2184 default "0x200000"
a0215061
KC
2185 range 0x2000 0x1000000 if X86_32
2186 range 0x200000 0x1000000 if X86_64
8f9ca475 2187 ---help---
506f1d07
SR
2188 This value puts the alignment restrictions on physical address
2189 where kernel is loaded and run from. Kernel is compiled for an
2190 address which meets above alignment restriction.
2191
2192 If bootloader loads the kernel at a non-aligned address and
2193 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2194 address aligned to above value and run from there.
2195
2196 If bootloader loads the kernel at a non-aligned address and
2197 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2198 load address and decompress itself to the address it has been
2199 compiled for and run from there. The address for which kernel is
2200 compiled already meets above alignment restrictions. Hence the
2201 end result is that kernel runs from a physical address meeting
2202 above alignment restrictions.
2203
a0215061
KC
2204 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2205 this value must be a multiple of 0x200000.
2206
506f1d07
SR
2207 Don't change this unless you know what you are doing.
2208
eedb92ab
KS
2209config DYNAMIC_MEMORY_LAYOUT
2210 bool
2211 ---help---
2212 This option makes base addresses of vmalloc and vmemmap as well as
2213 __PAGE_OFFSET movable during boot.
2214
0483e1fa
TG
2215config RANDOMIZE_MEMORY
2216 bool "Randomize the kernel memory sections"
2217 depends on X86_64
2218 depends on RANDOMIZE_BASE
eedb92ab 2219 select DYNAMIC_MEMORY_LAYOUT
0483e1fa
TG
2220 default RANDOMIZE_BASE
2221 ---help---
2222 Randomizes the base virtual address of kernel memory sections
2223 (physical memory mapping, vmalloc & vmemmap). This security feature
2224 makes exploits relying on predictable memory locations less reliable.
2225
2226 The order of allocations remains unchanged. Entropy is generated in
2227 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2228 configuration have in average 30,000 different possible virtual
2229 addresses for each memory section.
2230
6807c846 2231 If unsure, say Y.
0483e1fa 2232
90397a41
TG
2233config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2234 hex "Physical memory mapping padding" if EXPERT
2235 depends on RANDOMIZE_MEMORY
2236 default "0xa" if MEMORY_HOTPLUG
2237 default "0x0"
2238 range 0x1 0x40 if MEMORY_HOTPLUG
2239 range 0x0 0x40
2240 ---help---
2241 Define the padding in terabytes added to the existing physical
2242 memory size during kernel memory randomization. It is useful
2243 for memory hotplug support but reduces the entropy available for
2244 address randomization.
2245
2246 If unsure, leave at the default value.
2247
506f1d07 2248config HOTPLUG_CPU
bebd024e 2249 def_bool y
40b31360 2250 depends on SMP
506f1d07 2251
80aa1dff
FY
2252config BOOTPARAM_HOTPLUG_CPU0
2253 bool "Set default setting of cpu0_hotpluggable"
2c922cd0 2254 depends on HOTPLUG_CPU
80aa1dff
FY
2255 ---help---
2256 Set whether default state of cpu0_hotpluggable is on or off.
2257
2258 Say Y here to enable CPU0 hotplug by default. If this switch
2259 is turned on, there is no need to give cpu0_hotplug kernel
2260 parameter and the CPU0 hotplug feature is enabled by default.
2261
2262 Please note: there are two known CPU0 dependencies if you want
2263 to enable the CPU0 hotplug feature either by this switch or by
2264 cpu0_hotplug kernel parameter.
2265
2266 First, resume from hibernate or suspend always starts from CPU0.
2267 So hibernate and suspend are prevented if CPU0 is offline.
2268
2269 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2270 offline if any interrupt can not migrate out of CPU0. There may
2271 be other CPU0 dependencies.
2272
2273 Please make sure the dependencies are under your control before
2274 you enable this feature.
2275
2276 Say N if you don't want to enable CPU0 hotplug feature by default.
2277 You still can enable the CPU0 hotplug feature at boot by kernel
2278 parameter cpu0_hotplug.
2279
a71c8bc5
FY
2280config DEBUG_HOTPLUG_CPU0
2281 def_bool n
2282 prompt "Debug CPU0 hotplug"
2c922cd0 2283 depends on HOTPLUG_CPU
a71c8bc5
FY
2284 ---help---
2285 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2286 soon as possible and boots up userspace with CPU0 offlined. User
2287 can online CPU0 back after boot time.
2288
2289 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2290 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2291 compilation or giving cpu0_hotplug kernel parameter at boot.
2292
2293 If unsure, say N.
2294
506f1d07 2295config COMPAT_VDSO
b0b49f26
AL
2296 def_bool n
2297 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2298 depends on COMPAT_32
8f9ca475 2299 ---help---
b0b49f26
AL
2300 Certain buggy versions of glibc will crash if they are
2301 presented with a 32-bit vDSO that is not mapped at the address
2302 indicated in its segment table.
e84446de 2303
b0b49f26
AL
2304 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2305 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2306 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2307 the only released version with the bug, but OpenSUSE 9
2308 contains a buggy "glibc 2.3.2".
506f1d07 2309
b0b49f26
AL
2310 The symptom of the bug is that everything crashes on startup, saying:
2311 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2312
2313 Saying Y here changes the default value of the vdso32 boot
2314 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2315 This works around the glibc bug but hurts performance.
2316
2317 If unsure, say N: if you are compiling your own kernel, you
2318 are unlikely to be using a buggy version of glibc.
506f1d07 2319
3dc33bd3
KC
2320choice
2321 prompt "vsyscall table for legacy applications"
2322 depends on X86_64
625b7b7f 2323 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2324 help
2325 Legacy user code that does not know how to find the vDSO expects
2326 to be able to issue three syscalls by calling fixed addresses in
2327 kernel space. Since this location is not randomized with ASLR,
2328 it can be used to assist security vulnerability exploitation.
2329
2330 This setting can be changed at boot time via the kernel command
bd49e16e 2331 line parameter vsyscall=[emulate|xonly|none].
3dc33bd3
KC
2332
2333 On a system with recent enough glibc (2.14 or newer) and no
2334 static binaries, you can say None without a performance penalty
2335 to improve security.
2336
bd49e16e 2337 If unsure, select "Emulate execution only".
3dc33bd3 2338
3dc33bd3 2339 config LEGACY_VSYSCALL_EMULATE
bd49e16e 2340 bool "Full emulation"
3dc33bd3 2341 help
bd49e16e
AL
2342 The kernel traps and emulates calls into the fixed vsyscall
2343 address mapping. This makes the mapping non-executable, but
2344 it still contains readable known contents, which could be
2345 used in certain rare security vulnerability exploits. This
2346 configuration is recommended when using legacy userspace
2347 that still uses vsyscalls along with legacy binary
2348 instrumentation tools that require code to be readable.
2349
2350 An example of this type of legacy userspace is running
2351 Pin on an old binary that still uses vsyscalls.
2352
2353 config LEGACY_VSYSCALL_XONLY
2354 bool "Emulate execution only"
2355 help
2356 The kernel traps and emulates calls into the fixed vsyscall
2357 address mapping and does not allow reads. This
2358 configuration is recommended when userspace might use the
2359 legacy vsyscall area but support for legacy binary
2360 instrumentation of legacy code is not needed. It mitigates
2361 certain uses of the vsyscall area as an ASLR-bypassing
2362 buffer.
3dc33bd3
KC
2363
2364 config LEGACY_VSYSCALL_NONE
2365 bool "None"
2366 help
2367 There will be no vsyscall mapping at all. This will
2368 eliminate any risk of ASLR bypass due to the vsyscall
2369 fixed address mapping. Attempts to use the vsyscalls
2370 will be reported to dmesg, so that either old or
2371 malicious userspace programs can be identified.
2372
2373endchoice
2374
516cbf37
TB
2375config CMDLINE_BOOL
2376 bool "Built-in kernel command line"
8f9ca475 2377 ---help---
516cbf37
TB
2378 Allow for specifying boot arguments to the kernel at
2379 build time. On some systems (e.g. embedded ones), it is
2380 necessary or convenient to provide some or all of the
2381 kernel boot arguments with the kernel itself (that is,
2382 to not rely on the boot loader to provide them.)
2383
2384 To compile command line arguments into the kernel,
2385 set this option to 'Y', then fill in the
69711ca1 2386 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2387
2388 Systems with fully functional boot loaders (i.e. non-embedded)
2389 should leave this option set to 'N'.
2390
2391config CMDLINE
2392 string "Built-in kernel command string"
2393 depends on CMDLINE_BOOL
2394 default ""
8f9ca475 2395 ---help---
516cbf37
TB
2396 Enter arguments here that should be compiled into the kernel
2397 image and used at boot time. If the boot loader provides a
2398 command line at boot time, it is appended to this string to
2399 form the full kernel command line, when the system boots.
2400
2401 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2402 change this behavior.
2403
2404 In most cases, the command line (whether built-in or provided
2405 by the boot loader) should specify the device for the root
2406 file system.
2407
2408config CMDLINE_OVERRIDE
2409 bool "Built-in command line overrides boot loader arguments"
645e6466 2410 depends on CMDLINE_BOOL && CMDLINE != ""
8f9ca475 2411 ---help---
516cbf37
TB
2412 Set this option to 'Y' to have the kernel ignore the boot loader
2413 command line, and use ONLY the built-in command line.
2414
2415 This is used to work around broken boot loaders. This should
2416 be set to 'N' under normal conditions.
2417
a5b9e5a2
AL
2418config MODIFY_LDT_SYSCALL
2419 bool "Enable the LDT (local descriptor table)" if EXPERT
2420 default y
2421 ---help---
2422 Linux can allow user programs to install a per-process x86
2423 Local Descriptor Table (LDT) using the modify_ldt(2) system
2424 call. This is required to run 16-bit or segmented code such as
2425 DOSEMU or some Wine programs. It is also used by some very old
2426 threading libraries.
2427
2428 Enabling this feature adds a small amount of overhead to
2429 context switches and increases the low-level kernel attack
2430 surface. Disabling it removes the modify_ldt(2) system call.
2431
2432 Saying 'N' here may make sense for embedded or server kernels.
2433
b700e7f0
SJ
2434source "kernel/livepatch/Kconfig"
2435
506f1d07
SR
2436endmenu
2437
3072e413
MH
2438config ARCH_HAS_ADD_PAGES
2439 def_bool y
2440 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2441
506f1d07
SR
2442config ARCH_ENABLE_MEMORY_HOTPLUG
2443 def_bool y
2444 depends on X86_64 || (X86_32 && HIGHMEM)
2445
35551053
GH
2446config ARCH_ENABLE_MEMORY_HOTREMOVE
2447 def_bool y
2448 depends on MEMORY_HOTPLUG
2449
e534c7c5 2450config USE_PERCPU_NUMA_NODE_ID
645a7919 2451 def_bool y
e534c7c5
LS
2452 depends on NUMA
2453
9491846f
KS
2454config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2455 def_bool y
2456 depends on X86_64 || X86_PAE
2457
c177c81e
NH
2458config ARCH_ENABLE_HUGEPAGE_MIGRATION
2459 def_bool y
2460 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2461
9c670ea3
NH
2462config ARCH_ENABLE_THP_MIGRATION
2463 def_bool y
2464 depends on X86_64 && TRANSPARENT_HUGEPAGE
2465
da85f865 2466menu "Power management and ACPI options"
e279b6c1
SR
2467
2468config ARCH_HIBERNATION_HEADER
3c2362e6 2469 def_bool y
44556530 2470 depends on HIBERNATION
e279b6c1
SR
2471
2472source "kernel/power/Kconfig"
2473
2474source "drivers/acpi/Kconfig"
2475
efafc8b2
FT
2476source "drivers/sfi/Kconfig"
2477
a6b68076 2478config X86_APM_BOOT
6fc108a0 2479 def_bool y
282e5aab 2480 depends on APM
a6b68076 2481
e279b6c1
SR
2482menuconfig APM
2483 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2484 depends on X86_32 && PM_SLEEP
e279b6c1
SR
2485 ---help---
2486 APM is a BIOS specification for saving power using several different
2487 techniques. This is mostly useful for battery powered laptops with
2488 APM compliant BIOSes. If you say Y here, the system time will be
2489 reset after a RESUME operation, the /proc/apm device will provide
2490 battery status information, and user-space programs will receive
2491 notification of APM "events" (e.g. battery status change).
2492
2493 If you select "Y" here, you can disable actual use of the APM
2494 BIOS by passing the "apm=off" option to the kernel at boot time.
2495
2496 Note that the APM support is almost completely disabled for
2497 machines with more than one CPU.
2498
2499 In order to use APM, you will need supporting software. For location
151f4e2b 2500 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2501 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2502 <http://www.tldp.org/docs.html#howto>.
2503
2504 This driver does not spin down disk drives (see the hdparm(8)
2505 manpage ("man 8 hdparm") for that), and it doesn't turn off
2506 VESA-compliant "green" monitors.
2507
2508 This driver does not support the TI 4000M TravelMate and the ACER
2509 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2510 desktop machines also don't have compliant BIOSes, and this driver
2511 may cause those machines to panic during the boot phase.
2512
2513 Generally, if you don't have a battery in your machine, there isn't
2514 much point in using this driver and you should say N. If you get
2515 random kernel OOPSes or reboots that don't seem to be related to
2516 anything, try disabling/enabling this option (or disabling/enabling
2517 APM in your BIOS).
2518
2519 Some other things you should try when experiencing seemingly random,
2520 "weird" problems:
2521
2522 1) make sure that you have enough swap space and that it is
2523 enabled.
2524 2) pass the "no-hlt" option to the kernel
2525 3) switch on floating point emulation in the kernel and pass
2526 the "no387" option to the kernel
2527 4) pass the "floppy=nodma" option to the kernel
2528 5) pass the "mem=4M" option to the kernel (thereby disabling
2529 all but the first 4 MB of RAM)
2530 6) make sure that the CPU is not over clocked.
2531 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2532 8) disable the cache from your BIOS settings
2533 9) install a fan for the video card or exchange video RAM
2534 10) install a better fan for the CPU
2535 11) exchange RAM chips
2536 12) exchange the motherboard.
2537
2538 To compile this driver as a module, choose M here: the
2539 module will be called apm.
2540
2541if APM
2542
2543config APM_IGNORE_USER_SUSPEND
2544 bool "Ignore USER SUSPEND"
8f9ca475 2545 ---help---
e279b6c1
SR
2546 This option will ignore USER SUSPEND requests. On machines with a
2547 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2548 series notebooks, it is necessary to say Y because of a BIOS bug.
2549
2550config APM_DO_ENABLE
2551 bool "Enable PM at boot time"
2552 ---help---
2553 Enable APM features at boot time. From page 36 of the APM BIOS
2554 specification: "When disabled, the APM BIOS does not automatically
2555 power manage devices, enter the Standby State, enter the Suspend
2556 State, or take power saving steps in response to CPU Idle calls."
2557 This driver will make CPU Idle calls when Linux is idle (unless this
2558 feature is turned off -- see "Do CPU IDLE calls", below). This
2559 should always save battery power, but more complicated APM features
2560 will be dependent on your BIOS implementation. You may need to turn
2561 this option off if your computer hangs at boot time when using APM
2562 support, or if it beeps continuously instead of suspending. Turn
2563 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2564 T400CDT. This is off by default since most machines do fine without
2565 this feature.
2566
2567config APM_CPU_IDLE
dd8af076 2568 depends on CPU_IDLE
e279b6c1 2569 bool "Make CPU Idle calls when idle"
8f9ca475 2570 ---help---
e279b6c1
SR
2571 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2572 On some machines, this can activate improved power savings, such as
2573 a slowed CPU clock rate, when the machine is idle. These idle calls
2574 are made after the idle loop has run for some length of time (e.g.,
2575 333 mS). On some machines, this will cause a hang at boot time or
2576 whenever the CPU becomes idle. (On machines with more than one CPU,
2577 this option does nothing.)
2578
2579config APM_DISPLAY_BLANK
2580 bool "Enable console blanking using APM"
8f9ca475 2581 ---help---
e279b6c1
SR
2582 Enable console blanking using the APM. Some laptops can use this to
2583 turn off the LCD backlight when the screen blanker of the Linux
2584 virtual console blanks the screen. Note that this is only used by
2585 the virtual console screen blanker, and won't turn off the backlight
2586 when using the X Window system. This also doesn't have anything to
2587 do with your VESA-compliant power-saving monitor. Further, this
2588 option doesn't work for all laptops -- it might not turn off your
2589 backlight at all, or it might print a lot of errors to the console,
2590 especially if you are using gpm.
2591
2592config APM_ALLOW_INTS
2593 bool "Allow interrupts during APM BIOS calls"
8f9ca475 2594 ---help---
e279b6c1
SR
2595 Normally we disable external interrupts while we are making calls to
2596 the APM BIOS as a measure to lessen the effects of a badly behaving
2597 BIOS implementation. The BIOS should reenable interrupts if it
2598 needs to. Unfortunately, some BIOSes do not -- especially those in
2599 many of the newer IBM Thinkpads. If you experience hangs when you
2600 suspend, try setting this to Y. Otherwise, say N.
2601
e279b6c1
SR
2602endif # APM
2603
bb0a56ec 2604source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2605
2606source "drivers/cpuidle/Kconfig"
2607
27471fdb
AH
2608source "drivers/idle/Kconfig"
2609
e279b6c1
SR
2610endmenu
2611
2612
2613menu "Bus options (PCI etc.)"
2614
e279b6c1
SR
2615choice
2616 prompt "PCI access mode"
efefa6f6 2617 depends on X86_32 && PCI
e279b6c1
SR
2618 default PCI_GOANY
2619 ---help---
2620 On PCI systems, the BIOS can be used to detect the PCI devices and
2621 determine their configuration. However, some old PCI motherboards
2622 have BIOS bugs and may crash if this is done. Also, some embedded
2623 PCI-based systems don't have any BIOS at all. Linux can also try to
2624 detect the PCI hardware directly without using the BIOS.
2625
2626 With this option, you can specify how Linux should detect the
2627 PCI devices. If you choose "BIOS", the BIOS will be used,
2628 if you choose "Direct", the BIOS won't be used, and if you
2629 choose "MMConfig", then PCI Express MMCONFIG will be used.
2630 If you choose "Any", the kernel will try MMCONFIG, then the
2631 direct access method and falls back to the BIOS if that doesn't
2632 work. If unsure, go with the default, which is "Any".
2633
2634config PCI_GOBIOS
2635 bool "BIOS"
2636
2637config PCI_GOMMCONFIG
2638 bool "MMConfig"
2639
2640config PCI_GODIRECT
2641 bool "Direct"
2642
3ef0e1f8 2643config PCI_GOOLPC
76fb6570 2644 bool "OLPC XO-1"
3ef0e1f8
AS
2645 depends on OLPC
2646
2bdd1b03
AS
2647config PCI_GOANY
2648 bool "Any"
2649
e279b6c1
SR
2650endchoice
2651
2652config PCI_BIOS
3c2362e6 2653 def_bool y
efefa6f6 2654 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2655
2656# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2657config PCI_DIRECT
3c2362e6 2658 def_bool y
0aba496f 2659 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2660
2661config PCI_MMCONFIG
b45c9f36
JK
2662 bool "Support mmconfig PCI config space access" if X86_64
2663 default y
8364e1f8 2664 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
b45c9f36 2665 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2666
3ef0e1f8 2667config PCI_OLPC
2bdd1b03
AS
2668 def_bool y
2669 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2670
b5401a96
AN
2671config PCI_XEN
2672 def_bool y
2673 depends on PCI && XEN
2674 select SWIOTLB_XEN
2675
8364e1f8
JK
2676config MMCONF_FAM10H
2677 def_bool y
2678 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2679
3f6ea84a 2680config PCI_CNB20LE_QUIRK
6a108a14 2681 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2682 depends on PCI
3f6ea84a
IS
2683 help
2684 Read the PCI windows out of the CNB20LE host bridge. This allows
2685 PCI hotplug to work on systems with the CNB20LE chipset which do
2686 not have ACPI.
2687
64a5fed6
BH
2688 There's no public spec for this chipset, and this functionality
2689 is known to be incomplete.
2690
2691 You should say N unless you know you need this.
2692
3a495511 2693config ISA_BUS
17a2a129 2694 bool "ISA bus support on modern systems" if EXPERT
3a495511 2695 help
17a2a129
WBG
2696 Expose ISA bus device drivers and options available for selection and
2697 configuration. Enable this option if your target machine has an ISA
2698 bus. ISA is an older system, displaced by PCI and newer bus
2699 architectures -- if your target machine is modern, it probably does
2700 not have an ISA bus.
3a495511
WBG
2701
2702 If unsure, say N.
2703
1c00f016 2704# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2705config ISA_DMA_API
1c00f016
DR
2706 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2707 default y
2708 help
2709 Enables ISA-style DMA support for devices requiring such controllers.
2710 If unsure, say Y.
e279b6c1 2711
51e68d05
LT
2712if X86_32
2713
e279b6c1
SR
2714config ISA
2715 bool "ISA support"
8f9ca475 2716 ---help---
e279b6c1
SR
2717 Find out whether you have ISA slots on your motherboard. ISA is the
2718 name of a bus system, i.e. the way the CPU talks to the other stuff
2719 inside your box. Other bus systems are PCI, EISA, MicroChannel
2720 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2721 newer boards don't support it. If you have ISA, say Y, otherwise N.
2722
e279b6c1
SR
2723config SCx200
2724 tristate "NatSemi SCx200 support"
8f9ca475 2725 ---help---
e279b6c1
SR
2726 This provides basic support for National Semiconductor's
2727 (now AMD's) Geode processors. The driver probes for the
2728 PCI-IDs of several on-chip devices, so its a good dependency
2729 for other scx200_* drivers.
2730
2731 If compiled as a module, the driver is named scx200.
2732
2733config SCx200HR_TIMER
2734 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2735 depends on SCx200
e279b6c1 2736 default y
8f9ca475 2737 ---help---
e279b6c1
SR
2738 This driver provides a clocksource built upon the on-chip
2739 27MHz high-resolution timer. Its also a workaround for
2740 NSC Geode SC-1100's buggy TSC, which loses time when the
2741 processor goes idle (as is done by the scheduler). The
2742 other workaround is idle=poll boot option.
2743
3ef0e1f8
AS
2744config OLPC
2745 bool "One Laptop Per Child support"
54008979 2746 depends on !X86_PAE
3c554946 2747 select GPIOLIB
dc3119e7 2748 select OF
45bb1674 2749 select OF_PROMTREE
b4e51854 2750 select IRQ_DOMAIN
0c3d931b 2751 select OLPC_EC
8f9ca475 2752 ---help---
3ef0e1f8
AS
2753 Add support for detecting the unique features of the OLPC
2754 XO hardware.
2755
a3128588
DD
2756config OLPC_XO1_PM
2757 bool "OLPC XO-1 Power Management"
fa112cf1 2758 depends on OLPC && MFD_CS5535=y && PM_SLEEP
bf1ebf00 2759 ---help---
97c4cb71 2760 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2761
cfee9597
DD
2762config OLPC_XO1_RTC
2763 bool "OLPC XO-1 Real Time Clock"
2764 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2765 ---help---
2766 Add support for the XO-1 real time clock, which can be used as a
2767 programmable wakeup source.
2768
7feda8e9
DD
2769config OLPC_XO1_SCI
2770 bool "OLPC XO-1 SCI extras"
92e830f2 2771 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2772 depends on INPUT=y
d8d01a63 2773 select POWER_SUPPLY
7feda8e9
DD
2774 ---help---
2775 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2776 - EC-driven system wakeups
7feda8e9 2777 - Power button
7bc74b3d 2778 - Ebook switch
2cf2baea 2779 - Lid switch
e1040ac6
DD
2780 - AC adapter status updates
2781 - Battery status updates
7feda8e9 2782
a0f30f59
DD
2783config OLPC_XO15_SCI
2784 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2785 depends on OLPC && ACPI
2786 select POWER_SUPPLY
a0f30f59
DD
2787 ---help---
2788 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2789 - EC-driven system wakeups
2790 - AC adapter status updates
2791 - Battery status updates
bf1ebf00 2792
d4f3e350
EW
2793config ALIX
2794 bool "PCEngines ALIX System Support (LED setup)"
2795 select GPIOLIB
2796 ---help---
2797 This option enables system support for the PCEngines ALIX.
2798 At present this just sets up LEDs for GPIO control on
2799 ALIX2/3/6 boards. However, other system specific setup should
2800 get added here.
2801
2802 Note: You must still enable the drivers for GPIO and LED support
2803 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2804
2805 Note: You have to set alix.force=1 for boards with Award BIOS.
2806
da4e3302
PP
2807config NET5501
2808 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2809 select GPIOLIB
2810 ---help---
2811 This option enables system support for the Soekris Engineering net5501.
2812
3197059a
PP
2813config GEOS
2814 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2815 select GPIOLIB
2816 depends on DMI
2817 ---help---
2818 This option enables system support for the Traverse Technologies GEOS.
2819
7d029125
VD
2820config TS5500
2821 bool "Technologic Systems TS-5500 platform support"
2822 depends on MELAN
2823 select CHECK_SIGNATURE
2824 select NEW_LEDS
2825 select LEDS_CLASS
2826 ---help---
2827 This option enables system support for the Technologic Systems TS-5500.
2828
bc0120fd
SR
2829endif # X86_32
2830
23ac4ae8 2831config AMD_NB
e279b6c1 2832 def_bool y
0e152cd7 2833 depends on CPU_SUP_AMD && PCI
e279b6c1 2834
e3263ab3
DH
2835config X86_SYSFB
2836 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2837 help
2838 Firmwares often provide initial graphics framebuffers so the BIOS,
2839 bootloader or kernel can show basic video-output during boot for
2840 user-guidance and debugging. Historically, x86 used the VESA BIOS
2841 Extensions and EFI-framebuffers for this, which are mostly limited
2842 to x86.
2843 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2844 framebuffers so the new generic system-framebuffer drivers can be
2845 used on x86. If the framebuffer is not compatible with the generic
e3a5dc08 2846 modes, it is advertised as fallback platform framebuffer so legacy
e3263ab3
DH
2847 drivers like efifb, vesafb and uvesafb can pick it up.
2848 If this option is not selected, all system framebuffers are always
2849 marked as fallback platform framebuffers as usual.
2850
2851 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2852 not be able to pick up generic system framebuffers if this option
2853 is selected. You are highly encouraged to enable simplefb as
2854 replacement if you select this option. simplefb can correctly deal
2855 with generic system framebuffers. But you should still keep vesafb
2856 and others enabled as fallback if a system framebuffer is
2857 incompatible with simplefb.
2858
2859 If unsure, say Y.
2860
e279b6c1
SR
2861endmenu
2862
2863
1572497c 2864menu "Binary Emulations"
e279b6c1
SR
2865
2866config IA32_EMULATION
2867 bool "IA32 Emulation"
2868 depends on X86_64
39f88911 2869 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2870 select BINFMT_ELF
a97f52e6 2871 select COMPAT_BINFMT_ELF
39f88911 2872 select COMPAT_OLD_SIGACTION
8f9ca475 2873 ---help---
5fd92e65
L
2874 Include code to run legacy 32-bit programs under a
2875 64-bit kernel. You should likely turn this on, unless you're
2876 100% sure that you don't have any 32-bit programs left.
e279b6c1
SR
2877
2878config IA32_AOUT
8f9ca475
IM
2879 tristate "IA32 a.out support"
2880 depends on IA32_EMULATION
eac61655 2881 depends on BROKEN
8f9ca475
IM
2882 ---help---
2883 Support old a.out binaries in the 32bit emulation.
e279b6c1 2884
0bf62763 2885config X86_X32
6ea30386 2886 bool "x32 ABI for 64-bit mode"
9b54050b 2887 depends on X86_64
5fd92e65
L
2888 ---help---
2889 Include code to run binaries for the x32 native 32-bit ABI
2890 for 64-bit processors. An x32 process gets access to the
2891 full 64-bit register file and wide data path while leaving
2892 pointers at 32 bits for smaller memory footprint.
2893
2894 You will need a recent binutils (2.22 or later) with
2895 elf32_x86_64 support enabled to compile a kernel with this
2896 option set.
2897
953fee1d
IM
2898config COMPAT_32
2899 def_bool y
2900 depends on IA32_EMULATION || X86_32
2901 select HAVE_UID16
2902 select OLD_SIGSUSPEND3
2903
e279b6c1 2904config COMPAT
3c2362e6 2905 def_bool y
0bf62763 2906 depends on IA32_EMULATION || X86_X32
e279b6c1 2907
3120e25e 2908if COMPAT
e279b6c1 2909config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2910 def_bool y
e279b6c1
SR
2911
2912config SYSVIPC_COMPAT
3c2362e6 2913 def_bool y
3120e25e 2914 depends on SYSVIPC
3120e25e 2915endif
ee009e4a 2916
e279b6c1
SR
2917endmenu
2918
2919
e5beae16
KP
2920config HAVE_ATOMIC_IOMAP
2921 def_bool y
2922 depends on X86_32
2923
e279b6c1
SR
2924source "drivers/firmware/Kconfig"
2925
edf88417 2926source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
2927
2928source "arch/x86/Kconfig.assembler"