]> git.ipfire.org Git - thirdparty/linux.git/blame - arch/x86/Kconfig
Merge tag 'io_uring-5.7-2020-05-22' of git://git.kernel.dk/linux-block
[thirdparty/linux.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
ce4a4e56 95 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 96 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 97 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
3876d4a3 98 select ARCH_WANT_HUGE_PMD_SHARE
38d8b4e6 99 select ARCH_WANTS_THP_SWAP if X86_64
10916706 100 select BUILDTIME_TABLE_SORT
6471b825 101 select CLKEVT_I8253
6471b825
IM
102 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
103 select CLOCKSOURCE_WATCHDOG
6471b825 104 select DCACHE_WORD_ACCESS
45471cd9
LT
105 select EDAC_ATOMIC_SCRUB
106 select EDAC_SUPPORT
6471b825
IM
107 select GENERIC_CLOCKEVENTS
108 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
109 select GENERIC_CLOCKEVENTS_MIN_ADJUST
110 select GENERIC_CMOS_UPDATE
111 select GENERIC_CPU_AUTOPROBE
61dc0f55 112 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 113 select GENERIC_EARLY_IOREMAP
6471b825
IM
114 select GENERIC_FIND_FIRST_BIT
115 select GENERIC_IOMAP
c7d6c9dd 116 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 117 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 118 select GENERIC_IRQ_MIGRATION if SMP
6471b825 119 select GENERIC_IRQ_PROBE
c201c917 120 select GENERIC_IRQ_RESERVATION_MODE
6471b825
IM
121 select GENERIC_IRQ_SHOW
122 select GENERIC_PENDING_IRQ if SMP
2ae27137 123 select GENERIC_PTDUMP
6471b825
IM
124 select GENERIC_SMP_IDLE_THREAD
125 select GENERIC_STRNCPY_FROM_USER
126 select GENERIC_STRNLEN_USER
127 select GENERIC_TIME_VSYSCALL
7ac87074 128 select GENERIC_GETTIMEOFDAY
550a77a7 129 select GENERIC_VDSO_TIME_NS
39656e83 130 select GUP_GET_PTE_LOW_HIGH if X86_PAE
17e5888e 131 select HARDIRQS_SW_RESEND
7edaeb68 132 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
6471b825
IM
133 select HAVE_ACPI_APEI if ACPI
134 select HAVE_ACPI_APEI_NMI if ACPI
135 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
6471b825
IM
136 select HAVE_ARCH_AUDITSYSCALL
137 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
138 select HAVE_ARCH_JUMP_LABEL
b34006c4 139 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 140 select HAVE_ARCH_KASAN if X86_64
0609ae01 141 select HAVE_ARCH_KASAN_VMALLOC if X86_64
6471b825 142 select HAVE_ARCH_KGDB
9e08f57d
DC
143 select HAVE_ARCH_MMAP_RND_BITS if MMU
144 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 145 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 146 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 147 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 148 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 149 select HAVE_ARCH_STACKLEAK
6471b825
IM
150 select HAVE_ARCH_TRACEHOOK
151 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 152 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 153 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
e37e43a4 154 select HAVE_ARCH_VMAP_STACK if X86_64
c763ea26 155 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 156 select HAVE_ASM_MODVERSIONS
6471b825
IM
157 select HAVE_CMPXCHG_DOUBLE
158 select HAVE_CMPXCHG_LOCAL
159 select HAVE_CONTEXT_TRACKING if X86_64
c1bd55f9 160 select HAVE_COPY_THREAD_TLS
cf4db259 161 select HAVE_C_RECORDMCOUNT
6471b825 162 select HAVE_DEBUG_KMEMLEAK
6471b825 163 select HAVE_DMA_CONTIGUOUS
677aa9f7 164 select HAVE_DYNAMIC_FTRACE
06aeaaea 165 select HAVE_DYNAMIC_FTRACE_WITH_REGS
562955fe 166 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
03f5781b 167 select HAVE_EBPF_JIT
58340a07 168 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 169 select HAVE_EISA
5f56a5df 170 select HAVE_EXIT_THREAD
67a929e0 171 select HAVE_FAST_GUP
644e0e8d 172 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 173 select HAVE_FTRACE_MCOUNT_RECORD
6471b825
IM
174 select HAVE_FUNCTION_GRAPH_TRACER
175 select HAVE_FUNCTION_TRACER
6b90bd4b 176 select HAVE_GCC_PLUGINS
6471b825
IM
177 select HAVE_HW_BREAKPOINT
178 select HAVE_IDE
179 select HAVE_IOREMAP_PROT
180 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
181 select HAVE_IRQ_TIME_ACCOUNTING
2e9f3bdd 182 select HAVE_KERNEL_BZIP2
6471b825
IM
183 select HAVE_KERNEL_GZIP
184 select HAVE_KERNEL_LZ4
2e9f3bdd 185 select HAVE_KERNEL_LZMA
13510997 186 select HAVE_KERNEL_LZO
6471b825
IM
187 select HAVE_KERNEL_XZ
188 select HAVE_KPROBES
189 select HAVE_KPROBES_ON_FTRACE
540adea3 190 select HAVE_FUNCTION_ERROR_INJECTION
6471b825
IM
191 select HAVE_KRETPROBES
192 select HAVE_KVM
193 select HAVE_LIVEPATCH if X86_64
6471b825 194 select HAVE_MEMBLOCK_NODE_MAP
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
1ea7c673 599 select INTEL_SCU_IPC
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 1614config ARCH_HAVE_MEMORY_PRESENT
3c2362e6 1615 def_bool y
506f1d07 1616 depends on X86_32 && DISCONTIGMEM
506f1d07 1617
506f1d07
SR
1618config ARCH_FLATMEM_ENABLE
1619 def_bool y
3b16651f 1620 depends on X86_32 && !NUMA
506f1d07
SR
1621
1622config ARCH_DISCONTIGMEM_ENABLE
2792107d 1623 def_bool n
b263295d 1624 depends on NUMA && X86_32
2792107d 1625 depends on BROKEN
b263295d 1626
506f1d07
SR
1627config ARCH_SPARSEMEM_ENABLE
1628 def_bool y
6ea30386 1629 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1630 select SPARSEMEM_STATIC if X86_32
1631 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1632
3b16651f 1633config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1634 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1635
506f1d07
SR
1636config ARCH_SELECT_MEMORY_MODEL
1637 def_bool y
b263295d 1638 depends on ARCH_SPARSEMEM_ENABLE
506f1d07
SR
1639
1640config ARCH_MEMORY_PROBE
a0842b70 1641 bool "Enable sysfs memory/probe interface"
3120e25e 1642 depends on X86_64 && MEMORY_HOTPLUG
a0842b70
TK
1643 help
1644 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1645 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1646 If you are unsure how to answer this question, answer N.
506f1d07 1647
3b16651f
TH
1648config ARCH_PROC_KCORE_TEXT
1649 def_bool y
1650 depends on X86_64 && PROC_KCORE
1651
a29815a3 1652config ILLEGAL_POINTER_VALUE
b03b016f
KK
1653 hex
1654 default 0 if X86_32
1655 default 0xdead000000000000 if X86_64
a29815a3 1656
7a67832c
DW
1657config X86_PMEM_LEGACY_DEVICE
1658 bool
1659
ec776ef6 1660config X86_PMEM_LEGACY
7a67832c 1661 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1662 depends on PHYS_ADDR_T_64BIT
1663 depends on BLK_DEV
7a67832c 1664 select X86_PMEM_LEGACY_DEVICE
7b27a862 1665 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1666 select LIBNVDIMM
ec776ef6
CH
1667 help
1668 Treat memory marked using the non-standard e820 type of 12 as used
1669 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1670 The kernel will offer these regions to the 'pmem' driver so
1671 they can be used for persistent storage.
1672
1673 Say Y if unsure.
1674
506f1d07
SR
1675config HIGHPTE
1676 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1677 depends on HIGHMEM
8f9ca475 1678 ---help---
506f1d07
SR
1679 The VM uses one page table entry for each page of physical memory.
1680 For systems with a lot of RAM, this can be wasteful of precious
1681 low memory. Setting this option will put user-space page table
1682 entries in high memory.
1683
9f077871 1684config X86_CHECK_BIOS_CORRUPTION
8f9ca475
IM
1685 bool "Check for low memory corruption"
1686 ---help---
1687 Periodically check for memory corruption in low memory, which
1688 is suspected to be caused by BIOS. Even when enabled in the
1689 configuration, it is disabled at runtime. Enable it by
1690 setting "memory_corruption_check=1" on the kernel command
1691 line. By default it scans the low 64k of memory every 60
1692 seconds; see the memory_corruption_check_size and
1693 memory_corruption_check_period parameters in
8c27ceff 1694 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1695
1696 When enabled with the default parameters, this option has
1697 almost no overhead, as it reserves a relatively small amount
1698 of memory and scans it infrequently. It both detects corruption
1699 and prevents it from affecting the running system.
1700
1701 It is, however, intended as a diagnostic tool; if repeatable
1702 BIOS-originated corruption always affects the same memory,
1703 you can use memmap= to prevent the kernel from using that
1704 memory.
9f077871 1705
c885df50 1706config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1707 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1708 depends on X86_CHECK_BIOS_CORRUPTION
1709 default y
8f9ca475
IM
1710 ---help---
1711 Set whether the default state of memory_corruption_check is
1712 on or off.
c885df50 1713
9ea77bdb 1714config X86_RESERVE_LOW
d0cd7425
PA
1715 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1716 default 64
1717 range 4 640
8f9ca475 1718 ---help---
d0cd7425
PA
1719 Specify the amount of low memory to reserve for the BIOS.
1720
1721 The first page contains BIOS data structures that the kernel
1722 must not use, so that page must always be reserved.
1723
1724 By default we reserve the first 64K of physical RAM, as a
1725 number of BIOSes are known to corrupt that memory range
1726 during events such as suspend/resume or monitor cable
1727 insertion, so it must not be used by the kernel.
fc381519 1728
d0cd7425
PA
1729 You can set this to 4 if you are absolutely sure that you
1730 trust the BIOS to get all its memory reservations and usages
1731 right. If you know your BIOS have problems beyond the
1732 default 64K area, you can set this to 640 to avoid using the
1733 entire low memory range.
fc381519 1734
d0cd7425
PA
1735 If you have doubts about the BIOS (e.g. suspend/resume does
1736 not work or there's kernel crashes after certain hardware
1737 hotplug events) then you might want to enable
1738 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1739 typical corruption patterns.
fc381519 1740
d0cd7425 1741 Leave this to the default value of 64 if you are unsure.
fc381519 1742
506f1d07
SR
1743config MATH_EMULATION
1744 bool
a5b9e5a2 1745 depends on MODIFY_LDT_SYSCALL
87d6021b 1746 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
506f1d07
SR
1747 ---help---
1748 Linux can emulate a math coprocessor (used for floating point
1749 operations) if you don't have one. 486DX and Pentium processors have
1750 a math coprocessor built in, 486SX and 386 do not, unless you added
1751 a 487DX or 387, respectively. (The messages during boot time can
1752 give you some hints here ["man dmesg"].) Everyone needs either a
1753 coprocessor or this emulation.
1754
1755 If you don't have a math coprocessor, you need to say Y here; if you
1756 say Y here even though you have a coprocessor, the coprocessor will
1757 be used nevertheless. (This behavior can be changed with the kernel
1758 command line option "no387", which comes handy if your coprocessor
1759 is broken. Try "man bootparam" or see the documentation of your boot
1760 loader (lilo or loadlin) about how to pass options to the kernel at
1761 boot time.) This means that it is a good idea to say Y here if you
1762 intend to use this kernel on different machines.
1763
1764 More information about the internals of the Linux math coprocessor
1765 emulation can be found in <file:arch/x86/math-emu/README>.
1766
1767 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1768 kernel, it won't hurt.
1769
1770config MTRR
6fc108a0 1771 def_bool y
6a108a14 1772 prompt "MTRR (Memory Type Range Register) support" if EXPERT
506f1d07
SR
1773 ---help---
1774 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1775 the Memory Type Range Registers (MTRRs) may be used to control
1776 processor access to memory ranges. This is most useful if you have
1777 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1778 allows bus write transfers to be combined into a larger transfer
1779 before bursting over the PCI/AGP bus. This can increase performance
1780 of image write operations 2.5 times or more. Saying Y here creates a
1781 /proc/mtrr file which may be used to manipulate your processor's
1782 MTRRs. Typically the X server should use this.
1783
1784 This code has a reasonably generic interface so that similar
1785 control registers on other processors can be easily supported
1786 as well:
1787
1788 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1789 Registers (ARRs) which provide a similar functionality to MTRRs. For
1790 these, the ARRs are used to emulate the MTRRs.
1791 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1792 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1793 write-combining. All of these processors are supported by this code
1794 and it makes sense to say Y here if you have one of them.
1795
1796 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1797 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1798 can lead to all sorts of problems, so it's good to say Y here.
1799
1800 You can safely say Y even if your machine doesn't have MTRRs, you'll
1801 just add about 9 KB to your kernel.
1802
cb1aaebe 1803 See <file:Documentation/x86/mtrr.rst> for more information.
506f1d07 1804
95ffa243 1805config MTRR_SANITIZER
2ffb3501 1806 def_bool y
95ffa243
YL
1807 prompt "MTRR cleanup support"
1808 depends on MTRR
8f9ca475 1809 ---help---
aba3728c
TG
1810 Convert MTRR layout from continuous to discrete, so X drivers can
1811 add writeback entries.
95ffa243 1812
aba3728c 1813 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1814 The largest mtrr entry size for a continuous block can be set with
aba3728c 1815 mtrr_chunk_size.
95ffa243 1816
2ffb3501 1817 If unsure, say Y.
95ffa243
YL
1818
1819config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1820 int "MTRR cleanup enable value (0-1)"
1821 range 0 1
1822 default "0"
95ffa243 1823 depends on MTRR_SANITIZER
8f9ca475 1824 ---help---
f5098d62 1825 Enable mtrr cleanup default value
95ffa243 1826
12031a62
YL
1827config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1828 int "MTRR cleanup spare reg num (0-7)"
1829 range 0 7
1830 default "1"
1831 depends on MTRR_SANITIZER
8f9ca475 1832 ---help---
12031a62 1833 mtrr cleanup spare entries default, it can be changed via
aba3728c 1834 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1835
2e5d9c85 1836config X86_PAT
6fc108a0 1837 def_bool y
6a108a14 1838 prompt "x86 PAT support" if EXPERT
2a8a2719 1839 depends on MTRR
8f9ca475 1840 ---help---
2e5d9c85 1841 Use PAT attributes to setup page level cache control.
042b78e4 1842
2e5d9c85 1843 PATs are the modern equivalents of MTRRs and are much more
1844 flexible than MTRRs.
1845
1846 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1847 spontaneous reboots) or a non-working video driver.
2e5d9c85 1848
1849 If unsure, say Y.
1850
46cf98cd
VP
1851config ARCH_USES_PG_UNCACHED
1852 def_bool y
1853 depends on X86_PAT
1854
628c6246
PA
1855config ARCH_RANDOM
1856 def_bool y
1857 prompt "x86 architectural random number generator" if EXPERT
1858 ---help---
1859 Enable the x86 architectural RDRAND instruction
1860 (Intel Bull Mountain technology) to generate random numbers.
1861 If supported, this is a high bandwidth, cryptographically
1862 secure hardware random number generator.
1863
51ae4a2d
PA
1864config X86_SMAP
1865 def_bool y
1866 prompt "Supervisor Mode Access Prevention" if EXPERT
1867 ---help---
1868 Supervisor Mode Access Prevention (SMAP) is a security
1869 feature in newer Intel processors. There is a small
1870 performance cost if this enabled and turned on; there is
1871 also a small increase in the kernel size if this is enabled.
1872
1873 If unsure, say Y.
1874
b971880f 1875config X86_UMIP
796ebc81 1876 def_bool y
b971880f
BM
1877 prompt "User Mode Instruction Prevention" if EXPERT
1878 ---help---
1879 User Mode Instruction Prevention (UMIP) is a security feature in
1880 some x86 processors. If enabled, a general protection fault is
1881 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1882 executed in user mode. These instructions unnecessarily expose
1883 information about the hardware state.
796ebc81
RN
1884
1885 The vast majority of applications do not use these instructions.
1886 For the very few that do, software emulation is provided in
1887 specific cases in protected and virtual-8086 modes. Emulated
1888 results are dummy.
aa35f896 1889
35e97790 1890config X86_INTEL_MEMORY_PROTECTION_KEYS
284244a9 1891 prompt "Intel Memory Protection Keys"
35e97790 1892 def_bool y
284244a9 1893 # Note: only available in 64-bit mode
35e97790 1894 depends on CPU_SUP_INTEL && X86_64
52c8e601
IM
1895 select ARCH_USES_HIGH_VMA_FLAGS
1896 select ARCH_HAS_PKEYS
284244a9
DH
1897 ---help---
1898 Memory Protection Keys provides a mechanism for enforcing
1899 page-based protections, but without requiring modification of the
1900 page tables when an application changes protection domains.
1901
1eecbcdc 1902 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1903
1904 If unsure, say y.
35e97790 1905
db616173
MH
1906choice
1907 prompt "TSX enable mode"
1908 depends on CPU_SUP_INTEL
1909 default X86_INTEL_TSX_MODE_OFF
1910 help
1911 Intel's TSX (Transactional Synchronization Extensions) feature
1912 allows to optimize locking protocols through lock elision which
1913 can lead to a noticeable performance boost.
1914
1915 On the other hand it has been shown that TSX can be exploited
1916 to form side channel attacks (e.g. TAA) and chances are there
1917 will be more of those attacks discovered in the future.
1918
1919 Therefore TSX is not enabled by default (aka tsx=off). An admin
1920 might override this decision by tsx=on the command line parameter.
1921 Even with TSX enabled, the kernel will attempt to enable the best
1922 possible TAA mitigation setting depending on the microcode available
1923 for the particular machine.
1924
1925 This option allows to set the default tsx mode between tsx=on, =off
1926 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1927 details.
1928
1929 Say off if not sure, auto if TSX is in use but it should be used on safe
1930 platforms or on if TSX is in use and the security aspect of tsx is not
1931 relevant.
1932
1933config X86_INTEL_TSX_MODE_OFF
1934 bool "off"
1935 help
1936 TSX is disabled if possible - equals to tsx=off command line parameter.
1937
1938config X86_INTEL_TSX_MODE_ON
1939 bool "on"
1940 help
1941 TSX is always enabled on TSX capable HW - equals the tsx=on command
1942 line parameter.
1943
1944config X86_INTEL_TSX_MODE_AUTO
1945 bool "auto"
1946 help
1947 TSX is enabled on TSX capable HW that is believed to be safe against
1948 side channel attacks- equals the tsx=auto command line parameter.
1949endchoice
1950
506f1d07 1951config EFI
9ba16087 1952 bool "EFI runtime service support"
5b83683f 1953 depends on ACPI
f6ce5002 1954 select UCS2_STRING
022ee6c5 1955 select EFI_RUNTIME_WRAPPERS
506f1d07 1956 ---help---
8f9ca475
IM
1957 This enables the kernel to use EFI runtime services that are
1958 available (such as the EFI variable services).
506f1d07 1959
8f9ca475
IM
1960 This option is only useful on systems that have EFI firmware.
1961 In addition, you should use the latest ELILO loader available
1962 at <http://elilo.sourceforge.net> in order to take advantage
1963 of EFI runtime services. However, even with this option, the
1964 resultant kernel should continue to boot on existing non-EFI
1965 platforms.
506f1d07 1966
291f3632 1967config EFI_STUB
8f24f8c2
AB
1968 bool "EFI stub support"
1969 depends on EFI && !X86_USE_3DNOW
1970 depends on $(cc-option,-mabi=ms) || X86_32
1971 select RELOCATABLE
1972 ---help---
1973 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
1974 by EFI firmware without the use of a bootloader.
1975
4f4cfa6c 1976 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1977
7d453eee
MF
1978config EFI_MIXED
1979 bool "EFI mixed-mode support"
1980 depends on EFI_STUB && X86_64
1981 ---help---
1982 Enabling this feature allows a 64-bit kernel to be booted
1983 on a 32-bit firmware, provided that your CPU supports 64-bit
1984 mode.
1985
1986 Note that it is not possible to boot a mixed-mode enabled
1987 kernel via the EFI boot stub - a bootloader that supports
1988 the EFI handover protocol must be used.
1989
1990 If unsure, say N.
1991
506f1d07 1992config SECCOMP
3c2362e6
HH
1993 def_bool y
1994 prompt "Enable seccomp to safely compute untrusted bytecode"
8f9ca475 1995 ---help---
506f1d07
SR
1996 This kernel feature is useful for number crunching applications
1997 that may need to compute untrusted bytecode during their
1998 execution. By using pipes or other transports made available to
1999 the process as file descriptors supporting the read/write
2000 syscalls, it's possible to isolate those applications in
2001 their own address space using seccomp. Once seccomp is
9c0bbee8 2002 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
506f1d07
SR
2003 and the task is only allowed to execute a few safe syscalls
2004 defined by each seccomp mode.
2005
2006 If unsure, say Y. Only embedded should say N here.
2007
8636a1f9 2008source "kernel/Kconfig.hz"
506f1d07
SR
2009
2010config KEXEC
2011 bool "kexec system call"
2965faa5 2012 select KEXEC_CORE
8f9ca475 2013 ---help---
506f1d07
SR
2014 kexec is a system call that implements the ability to shutdown your
2015 current kernel, and to start another kernel. It is like a reboot
2016 but it is independent of the system firmware. And like a reboot
2017 you can start any kernel with it, not just Linux.
2018
2019 The name comes from the similarity to the exec system call.
2020
2021 It is an ongoing process to be certain the hardware in a machine
2022 is properly shutdown, so do not be surprised if this code does not
bf220695
GU
2023 initially work for you. As of this writing the exact hardware
2024 interface is strongly in flux, so no good recommendation can be
2025 made.
506f1d07 2026
74ca317c
VG
2027config KEXEC_FILE
2028 bool "kexec file based system call"
2965faa5 2029 select KEXEC_CORE
74ca317c 2030 select BUILD_BIN2C
74ca317c
VG
2031 depends on X86_64
2032 depends on CRYPTO=y
2033 depends on CRYPTO_SHA256=y
2034 ---help---
2035 This is new version of kexec system call. This system call is
2036 file based and takes file descriptors as system call argument
2037 for kernel and initramfs as opposed to list of segments as
2038 accepted by previous system call.
2039
b799a09f
AT
2040config ARCH_HAS_KEXEC_PURGATORY
2041 def_bool KEXEC_FILE
2042
99d5cadf 2043config KEXEC_SIG
8e7d8381 2044 bool "Verify kernel signature during kexec_file_load() syscall"
74ca317c 2045 depends on KEXEC_FILE
8e7d8381 2046 ---help---
d8eb8940 2047
99d5cadf
JB
2048 This option makes the kexec_file_load() syscall check for a valid
2049 signature of the kernel image. The image can still be loaded without
2050 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2051 there's a signature that we can check, then it must be valid.
2052
2053 In addition to this option, you need to enable signature
d8eb8940
BP
2054 verification for the corresponding kernel image type being
2055 loaded in order for this to work.
8e7d8381 2056
99d5cadf
JB
2057config KEXEC_SIG_FORCE
2058 bool "Require a valid signature in kexec_file_load() syscall"
2059 depends on KEXEC_SIG
2060 ---help---
2061 This option makes kernel signature verification mandatory for
2062 the kexec_file_load() syscall.
2063
8e7d8381
VG
2064config KEXEC_BZIMAGE_VERIFY_SIG
2065 bool "Enable bzImage signature verification support"
99d5cadf 2066 depends on KEXEC_SIG
8e7d8381
VG
2067 depends on SIGNED_PE_FILE_VERIFICATION
2068 select SYSTEM_TRUSTED_KEYRING
2069 ---help---
2070 Enable bzImage signature verification support.
2071
506f1d07 2072config CRASH_DUMP
04b69447 2073 bool "kernel crash dumps"
506f1d07 2074 depends on X86_64 || (X86_32 && HIGHMEM)
8f9ca475 2075 ---help---
506f1d07
SR
2076 Generate crash dump after being started by kexec.
2077 This should be normally only set in special crash dump kernels
2078 which are loaded in the main kernel with kexec-tools into
2079 a specially reserved region and then later executed after
2080 a crash by kdump/kexec. The crash dump kernel must be compiled
2081 to a memory address not used by the main kernel or BIOS using
2082 PHYSICAL_START, or it must be built as a relocatable image
2083 (CONFIG_RELOCATABLE=y).
330d4810 2084 For more details see Documentation/admin-guide/kdump/kdump.rst
506f1d07 2085
3ab83521 2086config KEXEC_JUMP
6ea30386 2087 bool "kexec jump"
fee7b0d8 2088 depends on KEXEC && HIBERNATION
8f9ca475 2089 ---help---
89081d17
HY
2090 Jump between original kernel and kexeced kernel and invoke
2091 code in physical address mode via KEXEC
3ab83521 2092
506f1d07 2093config PHYSICAL_START
6a108a14 2094 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2095 default "0x1000000"
8f9ca475 2096 ---help---
506f1d07
SR
2097 This gives the physical address where the kernel is loaded.
2098
2099 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2100 bzImage will decompress itself to above physical address and
2101 run from there. Otherwise, bzImage will run from the address where
2102 it has been loaded by the boot loader and will ignore above physical
2103 address.
2104
2105 In normal kdump cases one does not have to set/change this option
2106 as now bzImage can be compiled as a completely relocatable image
2107 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2108 address. This option is mainly useful for the folks who don't want
2109 to use a bzImage for capturing the crash dump and want to use a
2110 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2111 to be specifically compiled to run from a specific memory area
2112 (normally a reserved region) and this option comes handy.
2113
ceefccc9
PA
2114 So if you are using bzImage for capturing the crash dump,
2115 leave the value here unchanged to 0x1000000 and set
2116 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2117 for capturing the crash dump change this value to start of
2118 the reserved region. In other words, it can be set based on
2119 the "X" value as specified in the "crashkernel=YM@XM"
2120 command line boot parameter passed to the panic-ed
330d4810 2121 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2122 for more details about crash dumps.
506f1d07
SR
2123
2124 Usage of bzImage for capturing the crash dump is recommended as
2125 one does not have to build two kernels. Same kernel can be used
2126 as production kernel and capture kernel. Above option should have
2127 gone away after relocatable bzImage support is introduced. But it
2128 is present because there are users out there who continue to use
2129 vmlinux for dump capture. This option should go away down the
2130 line.
2131
2132 Don't change this unless you know what you are doing.
2133
2134config RELOCATABLE
26717808
PA
2135 bool "Build a relocatable kernel"
2136 default y
8f9ca475 2137 ---help---
506f1d07
SR
2138 This builds a kernel image that retains relocation information
2139 so it can be loaded someplace besides the default 1MB.
2140 The relocations tend to make the kernel binary about 10% larger,
2141 but are discarded at runtime.
2142
2143 One use is for the kexec on panic case where the recovery kernel
2144 must live at a different physical address than the primary
2145 kernel.
2146
2147 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2148 it has been loaded at and the compile time physical address
8ab3820f 2149 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2150
8ab3820f 2151config RANDOMIZE_BASE
e8581e3d 2152 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2153 depends on RELOCATABLE
6807c846 2154 default y
8ab3820f 2155 ---help---
e8581e3d
BH
2156 In support of Kernel Address Space Layout Randomization (KASLR),
2157 this randomizes the physical address at which the kernel image
2158 is decompressed and the virtual address where the kernel
2159 image is mapped, as a security feature that deters exploit
2160 attempts relying on knowledge of the location of kernel
2161 code internals.
2162
ed9f007e
KC
2163 On 64-bit, the kernel physical and virtual addresses are
2164 randomized separately. The physical address will be anywhere
2165 between 16MB and the top of physical memory (up to 64TB). The
2166 virtual address will be randomized from 16MB up to 1GB (9 bits
2167 of entropy). Note that this also reduces the memory space
2168 available to kernel modules from 1.5GB to 1GB.
2169
2170 On 32-bit, the kernel physical and virtual addresses are
2171 randomized together. They will be randomized from 16MB up to
2172 512MB (8 bits of entropy).
e8581e3d
BH
2173
2174 Entropy is generated using the RDRAND instruction if it is
2175 supported. If RDTSC is supported, its value is mixed into
2176 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2177 supported, then entropy is read from the i8254 timer. The
2178 usable entropy is limited by the kernel being built using
2179 2GB addressing, and that PHYSICAL_ALIGN must be at a
2180 minimum of 2MB. As a result, only 10 bits of entropy are
2181 theoretically possible, but the implementations are further
2182 limited due to memory layouts.
e8581e3d 2183
6807c846 2184 If unsure, say Y.
8ab3820f
KC
2185
2186# Relocation on x86 needs some additional build support
845adf72
PA
2187config X86_NEED_RELOCS
2188 def_bool y
8ab3820f 2189 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2190
506f1d07 2191config PHYSICAL_ALIGN
a0215061 2192 hex "Alignment value to which kernel should be aligned"
8ab3820f 2193 default "0x200000"
a0215061
KC
2194 range 0x2000 0x1000000 if X86_32
2195 range 0x200000 0x1000000 if X86_64
8f9ca475 2196 ---help---
506f1d07
SR
2197 This value puts the alignment restrictions on physical address
2198 where kernel is loaded and run from. Kernel is compiled for an
2199 address which meets above alignment restriction.
2200
2201 If bootloader loads the kernel at a non-aligned address and
2202 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2203 address aligned to above value and run from there.
2204
2205 If bootloader loads the kernel at a non-aligned address and
2206 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2207 load address and decompress itself to the address it has been
2208 compiled for and run from there. The address for which kernel is
2209 compiled already meets above alignment restrictions. Hence the
2210 end result is that kernel runs from a physical address meeting
2211 above alignment restrictions.
2212
a0215061
KC
2213 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2214 this value must be a multiple of 0x200000.
2215
506f1d07
SR
2216 Don't change this unless you know what you are doing.
2217
eedb92ab
KS
2218config DYNAMIC_MEMORY_LAYOUT
2219 bool
2220 ---help---
2221 This option makes base addresses of vmalloc and vmemmap as well as
2222 __PAGE_OFFSET movable during boot.
2223
0483e1fa
TG
2224config RANDOMIZE_MEMORY
2225 bool "Randomize the kernel memory sections"
2226 depends on X86_64
2227 depends on RANDOMIZE_BASE
eedb92ab 2228 select DYNAMIC_MEMORY_LAYOUT
0483e1fa
TG
2229 default RANDOMIZE_BASE
2230 ---help---
2231 Randomizes the base virtual address of kernel memory sections
2232 (physical memory mapping, vmalloc & vmemmap). This security feature
2233 makes exploits relying on predictable memory locations less reliable.
2234
2235 The order of allocations remains unchanged. Entropy is generated in
2236 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2237 configuration have in average 30,000 different possible virtual
2238 addresses for each memory section.
2239
6807c846 2240 If unsure, say Y.
0483e1fa 2241
90397a41
TG
2242config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2243 hex "Physical memory mapping padding" if EXPERT
2244 depends on RANDOMIZE_MEMORY
2245 default "0xa" if MEMORY_HOTPLUG
2246 default "0x0"
2247 range 0x1 0x40 if MEMORY_HOTPLUG
2248 range 0x0 0x40
2249 ---help---
2250 Define the padding in terabytes added to the existing physical
2251 memory size during kernel memory randomization. It is useful
2252 for memory hotplug support but reduces the entropy available for
2253 address randomization.
2254
2255 If unsure, leave at the default value.
2256
506f1d07 2257config HOTPLUG_CPU
bebd024e 2258 def_bool y
40b31360 2259 depends on SMP
506f1d07 2260
80aa1dff
FY
2261config BOOTPARAM_HOTPLUG_CPU0
2262 bool "Set default setting of cpu0_hotpluggable"
2c922cd0 2263 depends on HOTPLUG_CPU
80aa1dff
FY
2264 ---help---
2265 Set whether default state of cpu0_hotpluggable is on or off.
2266
2267 Say Y here to enable CPU0 hotplug by default. If this switch
2268 is turned on, there is no need to give cpu0_hotplug kernel
2269 parameter and the CPU0 hotplug feature is enabled by default.
2270
2271 Please note: there are two known CPU0 dependencies if you want
2272 to enable the CPU0 hotplug feature either by this switch or by
2273 cpu0_hotplug kernel parameter.
2274
2275 First, resume from hibernate or suspend always starts from CPU0.
2276 So hibernate and suspend are prevented if CPU0 is offline.
2277
2278 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2279 offline if any interrupt can not migrate out of CPU0. There may
2280 be other CPU0 dependencies.
2281
2282 Please make sure the dependencies are under your control before
2283 you enable this feature.
2284
2285 Say N if you don't want to enable CPU0 hotplug feature by default.
2286 You still can enable the CPU0 hotplug feature at boot by kernel
2287 parameter cpu0_hotplug.
2288
a71c8bc5
FY
2289config DEBUG_HOTPLUG_CPU0
2290 def_bool n
2291 prompt "Debug CPU0 hotplug"
2c922cd0 2292 depends on HOTPLUG_CPU
a71c8bc5
FY
2293 ---help---
2294 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2295 soon as possible and boots up userspace with CPU0 offlined. User
2296 can online CPU0 back after boot time.
2297
2298 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2299 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2300 compilation or giving cpu0_hotplug kernel parameter at boot.
2301
2302 If unsure, say N.
2303
506f1d07 2304config COMPAT_VDSO
b0b49f26
AL
2305 def_bool n
2306 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2307 depends on COMPAT_32
8f9ca475 2308 ---help---
b0b49f26
AL
2309 Certain buggy versions of glibc will crash if they are
2310 presented with a 32-bit vDSO that is not mapped at the address
2311 indicated in its segment table.
e84446de 2312
b0b49f26
AL
2313 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2314 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2315 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2316 the only released version with the bug, but OpenSUSE 9
2317 contains a buggy "glibc 2.3.2".
506f1d07 2318
b0b49f26
AL
2319 The symptom of the bug is that everything crashes on startup, saying:
2320 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2321
2322 Saying Y here changes the default value of the vdso32 boot
2323 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2324 This works around the glibc bug but hurts performance.
2325
2326 If unsure, say N: if you are compiling your own kernel, you
2327 are unlikely to be using a buggy version of glibc.
506f1d07 2328
3dc33bd3
KC
2329choice
2330 prompt "vsyscall table for legacy applications"
2331 depends on X86_64
625b7b7f 2332 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2333 help
2334 Legacy user code that does not know how to find the vDSO expects
2335 to be able to issue three syscalls by calling fixed addresses in
2336 kernel space. Since this location is not randomized with ASLR,
2337 it can be used to assist security vulnerability exploitation.
2338
2339 This setting can be changed at boot time via the kernel command
bd49e16e 2340 line parameter vsyscall=[emulate|xonly|none].
3dc33bd3
KC
2341
2342 On a system with recent enough glibc (2.14 or newer) and no
2343 static binaries, you can say None without a performance penalty
2344 to improve security.
2345
bd49e16e 2346 If unsure, select "Emulate execution only".
3dc33bd3 2347
3dc33bd3 2348 config LEGACY_VSYSCALL_EMULATE
bd49e16e 2349 bool "Full emulation"
3dc33bd3 2350 help
bd49e16e
AL
2351 The kernel traps and emulates calls into the fixed vsyscall
2352 address mapping. This makes the mapping non-executable, but
2353 it still contains readable known contents, which could be
2354 used in certain rare security vulnerability exploits. This
2355 configuration is recommended when using legacy userspace
2356 that still uses vsyscalls along with legacy binary
2357 instrumentation tools that require code to be readable.
2358
2359 An example of this type of legacy userspace is running
2360 Pin on an old binary that still uses vsyscalls.
2361
2362 config LEGACY_VSYSCALL_XONLY
2363 bool "Emulate execution only"
2364 help
2365 The kernel traps and emulates calls into the fixed vsyscall
2366 address mapping and does not allow reads. This
2367 configuration is recommended when userspace might use the
2368 legacy vsyscall area but support for legacy binary
2369 instrumentation of legacy code is not needed. It mitigates
2370 certain uses of the vsyscall area as an ASLR-bypassing
2371 buffer.
3dc33bd3
KC
2372
2373 config LEGACY_VSYSCALL_NONE
2374 bool "None"
2375 help
2376 There will be no vsyscall mapping at all. This will
2377 eliminate any risk of ASLR bypass due to the vsyscall
2378 fixed address mapping. Attempts to use the vsyscalls
2379 will be reported to dmesg, so that either old or
2380 malicious userspace programs can be identified.
2381
2382endchoice
2383
516cbf37
TB
2384config CMDLINE_BOOL
2385 bool "Built-in kernel command line"
8f9ca475 2386 ---help---
516cbf37
TB
2387 Allow for specifying boot arguments to the kernel at
2388 build time. On some systems (e.g. embedded ones), it is
2389 necessary or convenient to provide some or all of the
2390 kernel boot arguments with the kernel itself (that is,
2391 to not rely on the boot loader to provide them.)
2392
2393 To compile command line arguments into the kernel,
2394 set this option to 'Y', then fill in the
69711ca1 2395 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2396
2397 Systems with fully functional boot loaders (i.e. non-embedded)
2398 should leave this option set to 'N'.
2399
2400config CMDLINE
2401 string "Built-in kernel command string"
2402 depends on CMDLINE_BOOL
2403 default ""
8f9ca475 2404 ---help---
516cbf37
TB
2405 Enter arguments here that should be compiled into the kernel
2406 image and used at boot time. If the boot loader provides a
2407 command line at boot time, it is appended to this string to
2408 form the full kernel command line, when the system boots.
2409
2410 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2411 change this behavior.
2412
2413 In most cases, the command line (whether built-in or provided
2414 by the boot loader) should specify the device for the root
2415 file system.
2416
2417config CMDLINE_OVERRIDE
2418 bool "Built-in command line overrides boot loader arguments"
645e6466 2419 depends on CMDLINE_BOOL && CMDLINE != ""
8f9ca475 2420 ---help---
516cbf37
TB
2421 Set this option to 'Y' to have the kernel ignore the boot loader
2422 command line, and use ONLY the built-in command line.
2423
2424 This is used to work around broken boot loaders. This should
2425 be set to 'N' under normal conditions.
2426
a5b9e5a2
AL
2427config MODIFY_LDT_SYSCALL
2428 bool "Enable the LDT (local descriptor table)" if EXPERT
2429 default y
2430 ---help---
2431 Linux can allow user programs to install a per-process x86
2432 Local Descriptor Table (LDT) using the modify_ldt(2) system
2433 call. This is required to run 16-bit or segmented code such as
2434 DOSEMU or some Wine programs. It is also used by some very old
2435 threading libraries.
2436
2437 Enabling this feature adds a small amount of overhead to
2438 context switches and increases the low-level kernel attack
2439 surface. Disabling it removes the modify_ldt(2) system call.
2440
2441 Saying 'N' here may make sense for embedded or server kernels.
2442
b700e7f0
SJ
2443source "kernel/livepatch/Kconfig"
2444
506f1d07
SR
2445endmenu
2446
3072e413
MH
2447config ARCH_HAS_ADD_PAGES
2448 def_bool y
2449 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2450
506f1d07
SR
2451config ARCH_ENABLE_MEMORY_HOTPLUG
2452 def_bool y
2453 depends on X86_64 || (X86_32 && HIGHMEM)
2454
35551053
GH
2455config ARCH_ENABLE_MEMORY_HOTREMOVE
2456 def_bool y
2457 depends on MEMORY_HOTPLUG
2458
e534c7c5 2459config USE_PERCPU_NUMA_NODE_ID
645a7919 2460 def_bool y
e534c7c5
LS
2461 depends on NUMA
2462
9491846f
KS
2463config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2464 def_bool y
2465 depends on X86_64 || X86_PAE
2466
c177c81e
NH
2467config ARCH_ENABLE_HUGEPAGE_MIGRATION
2468 def_bool y
2469 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2470
9c670ea3
NH
2471config ARCH_ENABLE_THP_MIGRATION
2472 def_bool y
2473 depends on X86_64 && TRANSPARENT_HUGEPAGE
2474
da85f865 2475menu "Power management and ACPI options"
e279b6c1
SR
2476
2477config ARCH_HIBERNATION_HEADER
3c2362e6 2478 def_bool y
44556530 2479 depends on HIBERNATION
e279b6c1
SR
2480
2481source "kernel/power/Kconfig"
2482
2483source "drivers/acpi/Kconfig"
2484
efafc8b2
FT
2485source "drivers/sfi/Kconfig"
2486
a6b68076 2487config X86_APM_BOOT
6fc108a0 2488 def_bool y
282e5aab 2489 depends on APM
a6b68076 2490
e279b6c1
SR
2491menuconfig APM
2492 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2493 depends on X86_32 && PM_SLEEP
e279b6c1
SR
2494 ---help---
2495 APM is a BIOS specification for saving power using several different
2496 techniques. This is mostly useful for battery powered laptops with
2497 APM compliant BIOSes. If you say Y here, the system time will be
2498 reset after a RESUME operation, the /proc/apm device will provide
2499 battery status information, and user-space programs will receive
2500 notification of APM "events" (e.g. battery status change).
2501
2502 If you select "Y" here, you can disable actual use of the APM
2503 BIOS by passing the "apm=off" option to the kernel at boot time.
2504
2505 Note that the APM support is almost completely disabled for
2506 machines with more than one CPU.
2507
2508 In order to use APM, you will need supporting software. For location
151f4e2b 2509 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2510 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2511 <http://www.tldp.org/docs.html#howto>.
2512
2513 This driver does not spin down disk drives (see the hdparm(8)
2514 manpage ("man 8 hdparm") for that), and it doesn't turn off
2515 VESA-compliant "green" monitors.
2516
2517 This driver does not support the TI 4000M TravelMate and the ACER
2518 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2519 desktop machines also don't have compliant BIOSes, and this driver
2520 may cause those machines to panic during the boot phase.
2521
2522 Generally, if you don't have a battery in your machine, there isn't
2523 much point in using this driver and you should say N. If you get
2524 random kernel OOPSes or reboots that don't seem to be related to
2525 anything, try disabling/enabling this option (or disabling/enabling
2526 APM in your BIOS).
2527
2528 Some other things you should try when experiencing seemingly random,
2529 "weird" problems:
2530
2531 1) make sure that you have enough swap space and that it is
2532 enabled.
2533 2) pass the "no-hlt" option to the kernel
2534 3) switch on floating point emulation in the kernel and pass
2535 the "no387" option to the kernel
2536 4) pass the "floppy=nodma" option to the kernel
2537 5) pass the "mem=4M" option to the kernel (thereby disabling
2538 all but the first 4 MB of RAM)
2539 6) make sure that the CPU is not over clocked.
2540 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2541 8) disable the cache from your BIOS settings
2542 9) install a fan for the video card or exchange video RAM
2543 10) install a better fan for the CPU
2544 11) exchange RAM chips
2545 12) exchange the motherboard.
2546
2547 To compile this driver as a module, choose M here: the
2548 module will be called apm.
2549
2550if APM
2551
2552config APM_IGNORE_USER_SUSPEND
2553 bool "Ignore USER SUSPEND"
8f9ca475 2554 ---help---
e279b6c1
SR
2555 This option will ignore USER SUSPEND requests. On machines with a
2556 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2557 series notebooks, it is necessary to say Y because of a BIOS bug.
2558
2559config APM_DO_ENABLE
2560 bool "Enable PM at boot time"
2561 ---help---
2562 Enable APM features at boot time. From page 36 of the APM BIOS
2563 specification: "When disabled, the APM BIOS does not automatically
2564 power manage devices, enter the Standby State, enter the Suspend
2565 State, or take power saving steps in response to CPU Idle calls."
2566 This driver will make CPU Idle calls when Linux is idle (unless this
2567 feature is turned off -- see "Do CPU IDLE calls", below). This
2568 should always save battery power, but more complicated APM features
2569 will be dependent on your BIOS implementation. You may need to turn
2570 this option off if your computer hangs at boot time when using APM
2571 support, or if it beeps continuously instead of suspending. Turn
2572 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2573 T400CDT. This is off by default since most machines do fine without
2574 this feature.
2575
2576config APM_CPU_IDLE
dd8af076 2577 depends on CPU_IDLE
e279b6c1 2578 bool "Make CPU Idle calls when idle"
8f9ca475 2579 ---help---
e279b6c1
SR
2580 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2581 On some machines, this can activate improved power savings, such as
2582 a slowed CPU clock rate, when the machine is idle. These idle calls
2583 are made after the idle loop has run for some length of time (e.g.,
2584 333 mS). On some machines, this will cause a hang at boot time or
2585 whenever the CPU becomes idle. (On machines with more than one CPU,
2586 this option does nothing.)
2587
2588config APM_DISPLAY_BLANK
2589 bool "Enable console blanking using APM"
8f9ca475 2590 ---help---
e279b6c1
SR
2591 Enable console blanking using the APM. Some laptops can use this to
2592 turn off the LCD backlight when the screen blanker of the Linux
2593 virtual console blanks the screen. Note that this is only used by
2594 the virtual console screen blanker, and won't turn off the backlight
2595 when using the X Window system. This also doesn't have anything to
2596 do with your VESA-compliant power-saving monitor. Further, this
2597 option doesn't work for all laptops -- it might not turn off your
2598 backlight at all, or it might print a lot of errors to the console,
2599 especially if you are using gpm.
2600
2601config APM_ALLOW_INTS
2602 bool "Allow interrupts during APM BIOS calls"
8f9ca475 2603 ---help---
e279b6c1
SR
2604 Normally we disable external interrupts while we are making calls to
2605 the APM BIOS as a measure to lessen the effects of a badly behaving
2606 BIOS implementation. The BIOS should reenable interrupts if it
2607 needs to. Unfortunately, some BIOSes do not -- especially those in
2608 many of the newer IBM Thinkpads. If you experience hangs when you
2609 suspend, try setting this to Y. Otherwise, say N.
2610
e279b6c1
SR
2611endif # APM
2612
bb0a56ec 2613source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2614
2615source "drivers/cpuidle/Kconfig"
2616
27471fdb
AH
2617source "drivers/idle/Kconfig"
2618
e279b6c1
SR
2619endmenu
2620
2621
2622menu "Bus options (PCI etc.)"
2623
e279b6c1
SR
2624choice
2625 prompt "PCI access mode"
efefa6f6 2626 depends on X86_32 && PCI
e279b6c1
SR
2627 default PCI_GOANY
2628 ---help---
2629 On PCI systems, the BIOS can be used to detect the PCI devices and
2630 determine their configuration. However, some old PCI motherboards
2631 have BIOS bugs and may crash if this is done. Also, some embedded
2632 PCI-based systems don't have any BIOS at all. Linux can also try to
2633 detect the PCI hardware directly without using the BIOS.
2634
2635 With this option, you can specify how Linux should detect the
2636 PCI devices. If you choose "BIOS", the BIOS will be used,
2637 if you choose "Direct", the BIOS won't be used, and if you
2638 choose "MMConfig", then PCI Express MMCONFIG will be used.
2639 If you choose "Any", the kernel will try MMCONFIG, then the
2640 direct access method and falls back to the BIOS if that doesn't
2641 work. If unsure, go with the default, which is "Any".
2642
2643config PCI_GOBIOS
2644 bool "BIOS"
2645
2646config PCI_GOMMCONFIG
2647 bool "MMConfig"
2648
2649config PCI_GODIRECT
2650 bool "Direct"
2651
3ef0e1f8 2652config PCI_GOOLPC
76fb6570 2653 bool "OLPC XO-1"
3ef0e1f8
AS
2654 depends on OLPC
2655
2bdd1b03
AS
2656config PCI_GOANY
2657 bool "Any"
2658
e279b6c1
SR
2659endchoice
2660
2661config PCI_BIOS
3c2362e6 2662 def_bool y
efefa6f6 2663 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2664
2665# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2666config PCI_DIRECT
3c2362e6 2667 def_bool y
0aba496f 2668 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2669
2670config PCI_MMCONFIG
b45c9f36
JK
2671 bool "Support mmconfig PCI config space access" if X86_64
2672 default y
8364e1f8 2673 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
b45c9f36 2674 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2675
3ef0e1f8 2676config PCI_OLPC
2bdd1b03
AS
2677 def_bool y
2678 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2679
b5401a96
AN
2680config PCI_XEN
2681 def_bool y
2682 depends on PCI && XEN
2683 select SWIOTLB_XEN
2684
8364e1f8
JK
2685config MMCONF_FAM10H
2686 def_bool y
2687 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2688
3f6ea84a 2689config PCI_CNB20LE_QUIRK
6a108a14 2690 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2691 depends on PCI
3f6ea84a
IS
2692 help
2693 Read the PCI windows out of the CNB20LE host bridge. This allows
2694 PCI hotplug to work on systems with the CNB20LE chipset which do
2695 not have ACPI.
2696
64a5fed6
BH
2697 There's no public spec for this chipset, and this functionality
2698 is known to be incomplete.
2699
2700 You should say N unless you know you need this.
2701
3a495511 2702config ISA_BUS
17a2a129 2703 bool "ISA bus support on modern systems" if EXPERT
3a495511 2704 help
17a2a129
WBG
2705 Expose ISA bus device drivers and options available for selection and
2706 configuration. Enable this option if your target machine has an ISA
2707 bus. ISA is an older system, displaced by PCI and newer bus
2708 architectures -- if your target machine is modern, it probably does
2709 not have an ISA bus.
3a495511
WBG
2710
2711 If unsure, say N.
2712
1c00f016 2713# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2714config ISA_DMA_API
1c00f016
DR
2715 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2716 default y
2717 help
2718 Enables ISA-style DMA support for devices requiring such controllers.
2719 If unsure, say Y.
e279b6c1 2720
51e68d05
LT
2721if X86_32
2722
e279b6c1
SR
2723config ISA
2724 bool "ISA support"
8f9ca475 2725 ---help---
e279b6c1
SR
2726 Find out whether you have ISA slots on your motherboard. ISA is the
2727 name of a bus system, i.e. the way the CPU talks to the other stuff
2728 inside your box. Other bus systems are PCI, EISA, MicroChannel
2729 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2730 newer boards don't support it. If you have ISA, say Y, otherwise N.
2731
e279b6c1
SR
2732config SCx200
2733 tristate "NatSemi SCx200 support"
8f9ca475 2734 ---help---
e279b6c1
SR
2735 This provides basic support for National Semiconductor's
2736 (now AMD's) Geode processors. The driver probes for the
2737 PCI-IDs of several on-chip devices, so its a good dependency
2738 for other scx200_* drivers.
2739
2740 If compiled as a module, the driver is named scx200.
2741
2742config SCx200HR_TIMER
2743 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2744 depends on SCx200
e279b6c1 2745 default y
8f9ca475 2746 ---help---
e279b6c1
SR
2747 This driver provides a clocksource built upon the on-chip
2748 27MHz high-resolution timer. Its also a workaround for
2749 NSC Geode SC-1100's buggy TSC, which loses time when the
2750 processor goes idle (as is done by the scheduler). The
2751 other workaround is idle=poll boot option.
2752
3ef0e1f8
AS
2753config OLPC
2754 bool "One Laptop Per Child support"
54008979 2755 depends on !X86_PAE
3c554946 2756 select GPIOLIB
dc3119e7 2757 select OF
45bb1674 2758 select OF_PROMTREE
b4e51854 2759 select IRQ_DOMAIN
0c3d931b 2760 select OLPC_EC
8f9ca475 2761 ---help---
3ef0e1f8
AS
2762 Add support for detecting the unique features of the OLPC
2763 XO hardware.
2764
a3128588
DD
2765config OLPC_XO1_PM
2766 bool "OLPC XO-1 Power Management"
fa112cf1 2767 depends on OLPC && MFD_CS5535=y && PM_SLEEP
bf1ebf00 2768 ---help---
97c4cb71 2769 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2770
cfee9597
DD
2771config OLPC_XO1_RTC
2772 bool "OLPC XO-1 Real Time Clock"
2773 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2774 ---help---
2775 Add support for the XO-1 real time clock, which can be used as a
2776 programmable wakeup source.
2777
7feda8e9
DD
2778config OLPC_XO1_SCI
2779 bool "OLPC XO-1 SCI extras"
92e830f2 2780 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2781 depends on INPUT=y
d8d01a63 2782 select POWER_SUPPLY
7feda8e9
DD
2783 ---help---
2784 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2785 - EC-driven system wakeups
7feda8e9 2786 - Power button
7bc74b3d 2787 - Ebook switch
2cf2baea 2788 - Lid switch
e1040ac6
DD
2789 - AC adapter status updates
2790 - Battery status updates
7feda8e9 2791
a0f30f59
DD
2792config OLPC_XO15_SCI
2793 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2794 depends on OLPC && ACPI
2795 select POWER_SUPPLY
a0f30f59
DD
2796 ---help---
2797 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2798 - EC-driven system wakeups
2799 - AC adapter status updates
2800 - Battery status updates
bf1ebf00 2801
d4f3e350
EW
2802config ALIX
2803 bool "PCEngines ALIX System Support (LED setup)"
2804 select GPIOLIB
2805 ---help---
2806 This option enables system support for the PCEngines ALIX.
2807 At present this just sets up LEDs for GPIO control on
2808 ALIX2/3/6 boards. However, other system specific setup should
2809 get added here.
2810
2811 Note: You must still enable the drivers for GPIO and LED support
2812 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2813
2814 Note: You have to set alix.force=1 for boards with Award BIOS.
2815
da4e3302
PP
2816config NET5501
2817 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2818 select GPIOLIB
2819 ---help---
2820 This option enables system support for the Soekris Engineering net5501.
2821
3197059a
PP
2822config GEOS
2823 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2824 select GPIOLIB
2825 depends on DMI
2826 ---help---
2827 This option enables system support for the Traverse Technologies GEOS.
2828
7d029125
VD
2829config TS5500
2830 bool "Technologic Systems TS-5500 platform support"
2831 depends on MELAN
2832 select CHECK_SIGNATURE
2833 select NEW_LEDS
2834 select LEDS_CLASS
2835 ---help---
2836 This option enables system support for the Technologic Systems TS-5500.
2837
bc0120fd
SR
2838endif # X86_32
2839
23ac4ae8 2840config AMD_NB
e279b6c1 2841 def_bool y
0e152cd7 2842 depends on CPU_SUP_AMD && PCI
e279b6c1 2843
e3263ab3
DR
2844config X86_SYSFB
2845 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2846 help
2847 Firmwares often provide initial graphics framebuffers so the BIOS,
2848 bootloader or kernel can show basic video-output during boot for
2849 user-guidance and debugging. Historically, x86 used the VESA BIOS
2850 Extensions and EFI-framebuffers for this, which are mostly limited
2851 to x86.
2852 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2853 framebuffers so the new generic system-framebuffer drivers can be
2854 used on x86. If the framebuffer is not compatible with the generic
e3a5dc08 2855 modes, it is advertised as fallback platform framebuffer so legacy
e3263ab3
DR
2856 drivers like efifb, vesafb and uvesafb can pick it up.
2857 If this option is not selected, all system framebuffers are always
2858 marked as fallback platform framebuffers as usual.
2859
2860 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2861 not be able to pick up generic system framebuffers if this option
2862 is selected. You are highly encouraged to enable simplefb as
2863 replacement if you select this option. simplefb can correctly deal
2864 with generic system framebuffers. But you should still keep vesafb
2865 and others enabled as fallback if a system framebuffer is
2866 incompatible with simplefb.
2867
2868 If unsure, say Y.
2869
e279b6c1
SR
2870endmenu
2871
2872
1572497c 2873menu "Binary Emulations"
e279b6c1
SR
2874
2875config IA32_EMULATION
2876 bool "IA32 Emulation"
2877 depends on X86_64
39f88911 2878 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2879 select BINFMT_ELF
a97f52e6 2880 select COMPAT_BINFMT_ELF
39f88911 2881 select COMPAT_OLD_SIGACTION
8f9ca475 2882 ---help---
5fd92e65
L
2883 Include code to run legacy 32-bit programs under a
2884 64-bit kernel. You should likely turn this on, unless you're
2885 100% sure that you don't have any 32-bit programs left.
e279b6c1
SR
2886
2887config IA32_AOUT
8f9ca475
IM
2888 tristate "IA32 a.out support"
2889 depends on IA32_EMULATION
eac61655 2890 depends on BROKEN
8f9ca475
IM
2891 ---help---
2892 Support old a.out binaries in the 32bit emulation.
e279b6c1 2893
0bf62763 2894config X86_X32
6ea30386 2895 bool "x32 ABI for 64-bit mode"
9b54050b 2896 depends on X86_64
5fd92e65
L
2897 ---help---
2898 Include code to run binaries for the x32 native 32-bit ABI
2899 for 64-bit processors. An x32 process gets access to the
2900 full 64-bit register file and wide data path while leaving
2901 pointers at 32 bits for smaller memory footprint.
2902
2903 You will need a recent binutils (2.22 or later) with
2904 elf32_x86_64 support enabled to compile a kernel with this
2905 option set.
2906
953fee1d
IM
2907config COMPAT_32
2908 def_bool y
2909 depends on IA32_EMULATION || X86_32
2910 select HAVE_UID16
2911 select OLD_SIGSUSPEND3
2912
e279b6c1 2913config COMPAT
3c2362e6 2914 def_bool y
0bf62763 2915 depends on IA32_EMULATION || X86_X32
e279b6c1 2916
3120e25e 2917if COMPAT
e279b6c1 2918config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2919 def_bool y
e279b6c1
SR
2920
2921config SYSVIPC_COMPAT
3c2362e6 2922 def_bool y
3120e25e 2923 depends on SYSVIPC
3120e25e 2924endif
ee009e4a 2925
e279b6c1
SR
2926endmenu
2927
2928
e5beae16
KP
2929config HAVE_ATOMIC_IOMAP
2930 def_bool y
2931 depends on X86_32
2932
e279b6c1
SR
2933source "drivers/firmware/Kconfig"
2934
edf88417 2935source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
2936
2937source "arch/x86/Kconfig.assembler"