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b2441318 1# SPDX-License-Identifier: GPL-2.0
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SR
2# Select 32 or 64 bit
3config 64BIT
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MY
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
a7f7f624 6 help
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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
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JB
11 def_bool y
12 depends on !64BIT
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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
157e118b 17 select GENERIC_VDSO_32
117ed454 18 select HAVE_DEBUG_STACKOVERFLOW
157e118b 19 select KMAP_LOCAL
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IM
20 select MODULES_USE_ELF_REL
21 select OLD_SIGACTION
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SR
22
23config X86_64
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24 def_bool y
25 depends on 64BIT
d94e0685 26 # Options that are inherently 64-bit kernel only:
4eb0716e 27 select ARCH_HAS_GIGANTIC_PAGE
c12d3362 28 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
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IM
29 select ARCH_USE_CMPXCHG_LOCKREF
30 select HAVE_ARCH_SOFT_DIRTY
31 select MODULES_USE_ELF_RELA
f616ab59 32 select NEED_DMA_MAP_STATE
09230cbc 33 select SWIOTLB
1032c0ba 34
518049d9
SRV
35config FORCE_DYNAMIC_FTRACE
36 def_bool y
37 depends on X86_32
38 depends on FUNCTION_TRACER
39 select DYNAMIC_FTRACE
40 help
41 We keep the static function tracing (!DYNAMIC_FTRACE) around
42 in order to test the non static function tracing in the
43 generic code, as other architectures still use it. But we
44 only need to keep it around for x86_64. No need to keep it
45 for x86_32. For x86_32, force DYNAMIC_FTRACE.
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IM
46#
47# Arch settings
48#
49# ( Note that options that are marked 'if X86_64' could in principle be
50# ported to 32-bit as well. )
51#
8d5fffb9 52config X86
3c2362e6 53 def_bool y
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IM
54 #
55 # Note: keep this list sorted alphabetically
56 #
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57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
942fa985 59 select ARCH_32BIT_OFF_T if X86_32
2a21ad57 60 select ARCH_CLOCKSOURCE_INIT
c763ea26 61 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
fa5b6ec9 62 select ARCH_HAS_DEBUG_VIRTUAL
399145f9 63 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
21266be9 64 select ARCH_HAS_DEVMEM_IS_ALLOWED
b1a57bbf 65 select ARCH_HAS_EARLY_DEBUG if KGDB
6471b825 66 select ARCH_HAS_ELF_RANDOMIZE
72d93104 67 select ARCH_HAS_FAST_MULTIPLIER
316d097c 68 select ARCH_HAS_FILTER_PGPROT
6974f0c4 69 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 70 select ARCH_HAS_GCOV_PROFILE_ALL
0f1441b4 71 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
0c9c1d56 72 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 73 select ARCH_HAS_MEMBARRIER_SYNC_CORE
0ebeea8c 74 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
c763ea26 75 select ARCH_HAS_PMEM_API if X86_64
17596731 76 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 77 select ARCH_HAS_PTE_SPECIAL
0aed55af 78 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
ec6347bb 79 select ARCH_HAS_COPY_MC if X86_64
d2852a22 80 select ARCH_HAS_SET_MEMORY
d253ca0c 81 select ARCH_HAS_SET_DIRECT_MAP
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LA
82 select ARCH_HAS_STRICT_KERNEL_RWX
83 select ARCH_HAS_STRICT_MODULE_RWX
ac1ab12a 84 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
25c619e5 85 select ARCH_HAS_SYSCALL_WRAPPER
c6d30853 86 select ARCH_HAS_UBSAN_SANITIZE_ALL
7e01ccb4 87 select ARCH_HAS_DEBUG_WX
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IM
88 select ARCH_HAVE_NMI_SAFE_CMPXCHG
89 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 90 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 91 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 92 select ARCH_STACKWALK
2c870e61 93 select ARCH_SUPPORTS_ACPI
6471b825 94 select ARCH_SUPPORTS_ATOMIC_RMW
5d6ad668 95 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
6471b825 96 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
14df3267 97 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096
6471b825 98 select ARCH_USE_BUILTIN_BSWAP
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IM
99 select ARCH_USE_QUEUED_RWLOCKS
100 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 101 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 102 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 103 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 104 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
3876d4a3 105 select ARCH_WANT_HUGE_PMD_SHARE
59612b24 106 select ARCH_WANT_LD_ORPHAN_WARN
38d8b4e6 107 select ARCH_WANTS_THP_SWAP if X86_64
10916706 108 select BUILDTIME_TABLE_SORT
6471b825 109 select CLKEVT_I8253
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110 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
111 select CLOCKSOURCE_WATCHDOG
6471b825 112 select DCACHE_WORD_ACCESS
45471cd9
LT
113 select EDAC_ATOMIC_SCRUB
114 select EDAC_SUPPORT
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115 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
116 select GENERIC_CLOCKEVENTS_MIN_ADJUST
117 select GENERIC_CMOS_UPDATE
118 select GENERIC_CPU_AUTOPROBE
61dc0f55 119 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 120 select GENERIC_EARLY_IOREMAP
27d6b4d1 121 select GENERIC_ENTRY
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IM
122 select GENERIC_FIND_FIRST_BIT
123 select GENERIC_IOMAP
c7d6c9dd 124 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 125 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 126 select GENERIC_IRQ_MIGRATION if SMP
6471b825 127 select GENERIC_IRQ_PROBE
c201c917 128 select GENERIC_IRQ_RESERVATION_MODE
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129 select GENERIC_IRQ_SHOW
130 select GENERIC_PENDING_IRQ if SMP
2ae27137 131 select GENERIC_PTDUMP
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132 select GENERIC_SMP_IDLE_THREAD
133 select GENERIC_STRNCPY_FROM_USER
134 select GENERIC_STRNLEN_USER
135 select GENERIC_TIME_VSYSCALL
7ac87074 136 select GENERIC_GETTIMEOFDAY
550a77a7 137 select GENERIC_VDSO_TIME_NS
39656e83 138 select GUP_GET_PTE_LOW_HIGH if X86_PAE
17e5888e 139 select HARDIRQS_SW_RESEND
7edaeb68 140 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
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141 select HAVE_ACPI_APEI if ACPI
142 select HAVE_ACPI_APEI_NMI if ACPI
143 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
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144 select HAVE_ARCH_AUDITSYSCALL
145 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
146 select HAVE_ARCH_JUMP_LABEL
b34006c4 147 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 148 select HAVE_ARCH_KASAN if X86_64
0609ae01 149 select HAVE_ARCH_KASAN_VMALLOC if X86_64
6471b825 150 select HAVE_ARCH_KGDB
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DC
151 select HAVE_ARCH_MMAP_RND_BITS if MMU
152 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 153 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 154 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 155 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 156 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 157 select HAVE_ARCH_STACKLEAK
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158 select HAVE_ARCH_TRACEHOOK
159 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 160 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 161 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
e37e43a4 162 select HAVE_ARCH_VMAP_STACK if X86_64
c763ea26 163 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 164 select HAVE_ASM_MODVERSIONS
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165 select HAVE_CMPXCHG_DOUBLE
166 select HAVE_CMPXCHG_LOCAL
167 select HAVE_CONTEXT_TRACKING if X86_64
d1f250e2 168 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING
cf4db259 169 select HAVE_C_RECORDMCOUNT
6471b825 170 select HAVE_DEBUG_KMEMLEAK
6471b825 171 select HAVE_DMA_CONTIGUOUS
677aa9f7 172 select HAVE_DYNAMIC_FTRACE
06aeaaea 173 select HAVE_DYNAMIC_FTRACE_WITH_REGS
02a474ca 174 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64
562955fe 175 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
03f5781b 176 select HAVE_EBPF_JIT
58340a07 177 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 178 select HAVE_EISA
5f56a5df 179 select HAVE_EXIT_THREAD
67a929e0 180 select HAVE_FAST_GUP
644e0e8d 181 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 182 select HAVE_FTRACE_MCOUNT_RECORD
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183 select HAVE_FUNCTION_GRAPH_TRACER
184 select HAVE_FUNCTION_TRACER
6b90bd4b 185 select HAVE_GCC_PLUGINS
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186 select HAVE_HW_BREAKPOINT
187 select HAVE_IDE
188 select HAVE_IOREMAP_PROT
6471b825 189 select HAVE_IRQ_TIME_ACCOUNTING
2e9f3bdd 190 select HAVE_KERNEL_BZIP2
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191 select HAVE_KERNEL_GZIP
192 select HAVE_KERNEL_LZ4
2e9f3bdd 193 select HAVE_KERNEL_LZMA
13510997 194 select HAVE_KERNEL_LZO
6471b825 195 select HAVE_KERNEL_XZ
fb46d057 196 select HAVE_KERNEL_ZSTD
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197 select HAVE_KPROBES
198 select HAVE_KPROBES_ON_FTRACE
540adea3 199 select HAVE_FUNCTION_ERROR_INJECTION
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200 select HAVE_KRETPROBES
201 select HAVE_KVM
202 select HAVE_LIVEPATCH if X86_64
0102752e 203 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 204 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 205 select HAVE_MOVE_PMD
be37c98d 206 select HAVE_MOVE_PUD
42a0bb3f 207 select HAVE_NMI
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IM
208 select HAVE_OPROFILE
209 select HAVE_OPTPROBES
210 select HAVE_PCSPKR_PLATFORM
211 select HAVE_PERF_EVENTS
c01d4323 212 select HAVE_PERF_EVENTS_NMI
92e5aae4 213 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 214 select HAVE_PCI
c5e63197 215 select HAVE_PERF_REGS
c5ebcedb 216 select HAVE_PERF_USER_STACK_DUMP
ff2e6d72 217 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
00998085 218 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 219 select HAVE_REGS_AND_STACK_ACCESS_API
6415b38b 220 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
3c88ee19 221 select HAVE_FUNCTION_ARG_ACCESS_API
d148eac0 222 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
c763ea26 223 select HAVE_STACK_VALIDATION if X86_64
e6d6c071 224 select HAVE_STATIC_CALL
1e7e4788 225 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
d6761b8f 226 select HAVE_RSEQ
6471b825 227 select HAVE_SYSCALL_TRACEPOINTS
6471b825 228 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 229 select HAVE_USER_RETURN_NOTIFIER
7ac87074 230 select HAVE_GENERIC_VDSO
05736e4a 231 select HOTPLUG_SMT if SMP
c0185808 232 select IRQ_FORCED_THREADING
86596f0a 233 select NEED_SG_DMA_LENGTH
2eac9c2d 234 select PCI_DOMAINS if PCI
625210cf 235 select PCI_LOCKLESS_CONFIG if PCI
6471b825 236 select PERF_EVENTS
3195ef59 237 select RTC_LIB
d6faca40 238 select RTC_MC146818_LIB
6471b825 239 select SPARSE_IRQ
83fe27ea 240 select SRCU
1e7e4788 241 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
6471b825 242 select SYSCTL_EXCEPTION_TRACE
15f4eae7 243 select THREAD_INFO_IN_TASK
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IM
244 select USER_STACKTRACE_SUPPORT
245 select VIRT_TO_BUS
3b02a051 246 select HAVE_ARCH_KCSAN if X86_64
6471b825 247 select X86_FEATURE_NAMES if PROC_FS
0c608dad 248 select PROC_PID_ARCH_STATUS if PROC_FS
9e2b4be3 249 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
7d8330a5 250
ba7e4d13 251config INSTRUCTION_DECODER
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252 def_bool y
253 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 254
51b26ada
LT
255config OUTPUT_FORMAT
256 string
257 default "elf32-i386" if X86_32
258 default "elf64-x86-64" if X86_64
259
8d5fffb9 260config LOCKDEP_SUPPORT
3c2362e6 261 def_bool y
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SR
262
263config STACKTRACE_SUPPORT
3c2362e6 264 def_bool y
8d5fffb9 265
8d5fffb9 266config MMU
3c2362e6 267 def_bool y
8d5fffb9 268
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DC
269config ARCH_MMAP_RND_BITS_MIN
270 default 28 if 64BIT
271 default 8
272
273config ARCH_MMAP_RND_BITS_MAX
274 default 32 if 64BIT
275 default 16
276
277config ARCH_MMAP_RND_COMPAT_BITS_MIN
278 default 8
279
280config ARCH_MMAP_RND_COMPAT_BITS_MAX
281 default 16
282
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SR
283config SBUS
284 bool
285
286config GENERIC_ISA_DMA
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JB
287 def_bool y
288 depends on ISA_DMA_API
8d5fffb9 289
8d5fffb9 290config GENERIC_BUG
3c2362e6 291 def_bool y
8d5fffb9 292 depends on BUG
b93a531e
JB
293 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
294
295config GENERIC_BUG_RELATIVE_POINTERS
296 bool
8d5fffb9 297
8d5fffb9 298config ARCH_MAY_HAVE_PC_FDC
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JB
299 def_bool y
300 depends on ISA_DMA_API
8d5fffb9 301
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SR
302config GENERIC_CALIBRATE_DELAY
303 def_bool y
304
9a0b8415 305config ARCH_HAS_CPU_RELAX
306 def_bool y
307
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308config ARCH_HAS_CACHE_LINE_SIZE
309 def_bool y
310
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DH
311config ARCH_HAS_FILTER_PGPROT
312 def_bool y
313
dd5af90a 314config HAVE_SETUP_PER_CPU_AREA
89c9c4c5 315 def_bool y
b32ef636 316
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TH
317config NEED_PER_CPU_EMBED_FIRST_CHUNK
318 def_bool y
319
320config NEED_PER_CPU_PAGE_FIRST_CHUNK
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TH
321 def_bool y
322
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JB
323config ARCH_HIBERNATION_POSSIBLE
324 def_bool y
801e4062 325
f4cb5700
JB
326config ARCH_SUSPEND_POSSIBLE
327 def_bool y
f4cb5700 328
53313b2c
SC
329config ARCH_WANT_GENERAL_HUGETLB
330 def_bool y
331
8d5fffb9 332config ZONE_DMA32
e0fd24a3 333 def_bool y if X86_64
8d5fffb9 334
8d5fffb9 335config AUDIT_ARCH
e0fd24a3 336 def_bool y if X86_64
8d5fffb9 337
d6f2d75a
AR
338config KASAN_SHADOW_OFFSET
339 hex
340 depends on KASAN
341 default 0xdffffc0000000000
342
69575d38
SW
343config HAVE_INTEL_TXT
344 def_bool y
6ea30386 345 depends on INTEL_IOMMU && ACPI
69575d38 346
6b0c3d44
SR
347config X86_32_SMP
348 def_bool y
349 depends on X86_32 && SMP
350
351config X86_64_SMP
352 def_bool y
353 depends on X86_64 && SMP
354
ccbeed3a
TH
355config X86_32_LAZY_GS
356 def_bool y
8458f8c2 357 depends on X86_32 && !STACKPROTECTOR
ccbeed3a 358
2b144498
SD
359config ARCH_SUPPORTS_UPROBES
360 def_bool y
361
d20642f0
RH
362config FIX_EARLYCON_MEM
363 def_bool y
364
94d49eb3
KS
365config DYNAMIC_PHYSICAL_MASK
366 bool
367
98233368
KS
368config PGTABLE_LEVELS
369 int
77ef56e4 370 default 5 if X86_5LEVEL
98233368
KS
371 default 4 if X86_64
372 default 3 if X86_PAE
373 default 2
374
2a61f474
MY
375config CC_HAS_SANE_STACKPROTECTOR
376 bool
377 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
378 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
379 help
380 We have to make sure stack protector is unconditionally disabled if
381 the compiler produces broken code.
382
506f1d07
SR
383menu "Processor type and features"
384
5ee71535
RD
385config ZONE_DMA
386 bool "DMA memory allocation support" if EXPERT
387 default y
388 help
389 DMA memory allocation support allows devices with less than 32-bit
390 addressing to allocate within the first 16MB of address space.
391 Disable if no such devices will be used.
392
393 If unsure, say Y.
394
506f1d07
SR
395config SMP
396 bool "Symmetric multi-processing support"
a7f7f624 397 help
506f1d07 398 This enables support for systems with more than one CPU. If you have
4a474157
RG
399 a system with only one CPU, say N. If you have a system with more
400 than one CPU, say Y.
506f1d07 401
4a474157 402 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
403 machines, but will use only one CPU of a multiprocessor machine. If
404 you say Y here, the kernel will run on many, but not all,
4a474157 405 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
406 will run faster if you say N here.
407
408 Note that if you say Y here and choose architecture "586" or
409 "Pentium" under "Processor family", the kernel will not work on 486
410 architectures. Similarly, multiprocessor kernels for the "PPro"
411 architecture may not work on all Pentium based boards.
412
413 People using multiprocessor machines who say Y here should also say
414 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
415 Management" code will be disabled if you say Y here.
416
cb1aaebe 417 See also <file:Documentation/x86/i386/IO-APIC.rst>,
4f4cfa6c 418 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
419 <http://www.tldp.org/docs.html#howto>.
420
421 If you don't know what to do here, say N.
422
9def39be
JT
423config X86_FEATURE_NAMES
424 bool "Processor feature human-readable names" if EMBEDDED
425 default y
a7f7f624 426 help
9def39be
JT
427 This option compiles in a table of x86 feature bits and corresponding
428 names. This is required to support /proc/cpuinfo and a few kernel
429 messages. You can disable this to save space, at the expense of
430 making those few kernel messages show numeric feature bits instead.
431
432 If in doubt, say Y.
433
06cd9a7d
YL
434config X86_X2APIC
435 bool "Support x2apic"
19e3d60d 436 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 437 help
06cd9a7d
YL
438 This enables x2apic support on CPUs that have this feature.
439
440 This allows 32-bit apic IDs (so it can support very large systems),
441 and accesses the local apic via MSRs not via mmio.
442
06cd9a7d
YL
443 If you don't know what to do here, say N.
444
6695c85b 445config X86_MPPARSE
6e87f9b7 446 bool "Enable MPS table" if ACPI || SFI
7a527688 447 default y
5ab74722 448 depends on X86_LOCAL_APIC
a7f7f624 449 help
6695c85b
YL
450 For old smp systems that do not have proper acpi support. Newer systems
451 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 452
ddd70cf9 453config GOLDFISH
b03b016f
KK
454 def_bool y
455 depends on X86_GOLDFISH
ddd70cf9 456
76b04384
DW
457config RETPOLINE
458 bool "Avoid speculative indirect branches in kernel"
459 default y
460 help
461 Compile kernel with the retpoline compiler options to guard against
462 kernel-to-user data leaks by avoiding speculative indirect
463 branches. Requires a compiler with -mindirect-branch=thunk-extern
464 support for full protection. The kernel may run slower.
465
e6d42931
JW
466config X86_CPU_RESCTRL
467 bool "x86 CPU resource control support"
6fe07ce3 468 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 469 select KERNFS
e79f15a4 470 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 471 help
e6d42931 472 Enable x86 CPU resource control support.
6fe07ce3
BM
473
474 Provide support for the allocation and monitoring of system resources
475 usage by the CPU.
476
477 Intel calls this Intel Resource Director Technology
478 (Intel(R) RDT). More information about RDT can be found in the
479 Intel x86 Architecture Software Developer Manual.
480
481 AMD calls this AMD Platform Quality of Service (AMD QoS).
482 More information about AMD QoS can be found in the AMD64 Technology
483 Platform Quality of Service Extensions manual.
78e99b4a
FY
484
485 Say N if unsure.
486
8425091f 487if X86_32
a0d0bb4d
RD
488config X86_BIGSMP
489 bool "Support for big SMP systems with more than 8 CPUs"
490 depends on SMP
a7f7f624 491 help
e133f6ea 492 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 493
c5c606d9
RT
494config X86_EXTENDED_PLATFORM
495 bool "Support for extended (non-PC) x86 platforms"
496 default y
a7f7f624 497 help
06ac8346
IM
498 If you disable this option then the kernel will only support
499 standard PC platforms. (which covers the vast majority of
500 systems out there.)
501
8425091f
RT
502 If you enable this option then you'll be able to select support
503 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 504 Goldfish (Android emulator)
8425091f 505 AMD Elan
8425091f
RT
506 RDC R-321x SoC
507 SGI 320/540 (Visual Workstation)
83125a3a 508 STA2X11-based (e.g. Northville)
3f4110a4 509 Moorestown MID devices
06ac8346
IM
510
511 If you have one of these systems, or if you want to build a
512 generic distribution kernel, say Y here - otherwise say N.
8425091f 513endif
06ac8346 514
8425091f
RT
515if X86_64
516config X86_EXTENDED_PLATFORM
517 bool "Support for extended (non-PC) x86 platforms"
518 default y
a7f7f624 519 help
8425091f
RT
520 If you disable this option then the kernel will only support
521 standard PC platforms. (which covers the vast majority of
522 systems out there.)
523
524 If you enable this option then you'll be able to select support
525 for the following (non-PC) 64 bit x86 platforms:
44b111b5 526 Numascale NumaChip
8425091f
RT
527 ScaleMP vSMP
528 SGI Ultraviolet
529
530 If you have one of these systems, or if you want to build a
531 generic distribution kernel, say Y here - otherwise say N.
532endif
c5c606d9
RT
533# This is an alphabetically sorted list of 64 bit extended platforms
534# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
535config X86_NUMACHIP
536 bool "Numascale NumaChip"
537 depends on X86_64
538 depends on X86_EXTENDED_PLATFORM
539 depends on NUMA
540 depends on SMP
541 depends on X86_X2APIC
f9726bfd 542 depends on PCI_MMCONFIG
a7f7f624 543 help
44b111b5
SP
544 Adds support for Numascale NumaChip large-SMP systems. Needed to
545 enable more than ~168 cores.
546 If you don't have one of these, you should say N here.
506f1d07 547
c5c606d9
RT
548config X86_VSMP
549 bool "ScaleMP vSMP"
6276a074 550 select HYPERVISOR_GUEST
c5c606d9
RT
551 select PARAVIRT
552 depends on X86_64 && PCI
553 depends on X86_EXTENDED_PLATFORM
ead91d4b 554 depends on SMP
a7f7f624 555 help
c5c606d9
RT
556 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
557 supposed to run on these EM64T-based machines. Only choose this option
558 if you have one of these machines.
5e3a77e9 559
03b48632
NP
560config X86_UV
561 bool "SGI Ultraviolet"
562 depends on X86_64
c5c606d9 563 depends on X86_EXTENDED_PLATFORM
54c28d29 564 depends on NUMA
1ecb4ae5 565 depends on EFI
9d6c26e7 566 depends on X86_X2APIC
1222e564 567 depends on PCI
a7f7f624 568 help
03b48632
NP
569 This option is needed in order to support SGI Ultraviolet systems.
570 If you don't have one of these, you should say N here.
571
c5c606d9
RT
572# Following is an alphabetically sorted list of 32 bit extended platforms
573# Please maintain the alphabetic order if and when there are additions
506f1d07 574
ddd70cf9 575config X86_GOLDFISH
b03b016f
KK
576 bool "Goldfish (Virtual Platform)"
577 depends on X86_EXTENDED_PLATFORM
a7f7f624 578 help
ddd70cf9
JN
579 Enable support for the Goldfish virtual platform used primarily
580 for Android development. Unless you are building for the Android
581 Goldfish emulator say N here.
582
c751e17b
TG
583config X86_INTEL_CE
584 bool "CE4100 TV platform"
585 depends on PCI
586 depends on PCI_GODIRECT
6084a6e2 587 depends on X86_IO_APIC
c751e17b
TG
588 depends on X86_32
589 depends on X86_EXTENDED_PLATFORM
37bc9f50 590 select X86_REBOOTFIXUPS
da6b737b
SAS
591 select OF
592 select OF_EARLY_FLATTREE
a7f7f624 593 help
c751e17b
TG
594 Select for the Intel CE media processor (CE4100) SOC.
595 This option compiles in support for the CE4100 SOC for settop
596 boxes and media devices.
597
4cb9b00f 598config X86_INTEL_MID
43605ef1 599 bool "Intel MID platform support"
43605ef1 600 depends on X86_EXTENDED_PLATFORM
edc6bc78 601 depends on X86_PLATFORM_DEVICES
1ea7c673 602 depends on PCI
3fda5bb4 603 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 604 depends on X86_IO_APIC
7c9c3a1e 605 select SFI
4cb9b00f 606 select I2C
7c9c3a1e 607 select DW_APB_TIMER
1ea7c673 608 select APB_TIMER
54b34aa0 609 select INTEL_SCU_PCI
15a713df 610 select MFD_INTEL_MSIC
a7f7f624 611 help
4cb9b00f
DC
612 Select to build a kernel capable of supporting Intel MID (Mobile
613 Internet Device) platform systems which do not have the PCI legacy
614 interfaces. If you are building for a PC class system say N here.
1ea7c673 615
4cb9b00f
DC
616 Intel MID platforms are based on an Intel processor and chipset which
617 consume less power than most of the x86 derivatives.
43605ef1 618
8bbc2a13
BD
619config X86_INTEL_QUARK
620 bool "Intel Quark platform support"
621 depends on X86_32
622 depends on X86_EXTENDED_PLATFORM
623 depends on X86_PLATFORM_DEVICES
624 depends on X86_TSC
625 depends on PCI
626 depends on PCI_GOANY
627 depends on X86_IO_APIC
628 select IOSF_MBI
629 select INTEL_IMR
9ab6eb51 630 select COMMON_CLK
a7f7f624 631 help
8bbc2a13
BD
632 Select to include support for Quark X1000 SoC.
633 Say Y here if you have a Quark based system such as the Arduino
634 compatible Intel Galileo.
635
3d48aab1
MW
636config X86_INTEL_LPSS
637 bool "Intel Low Power Subsystem Support"
5962dd22 638 depends on X86 && ACPI && PCI
3d48aab1 639 select COMMON_CLK
0f531431 640 select PINCTRL
eebb3e8d 641 select IOSF_MBI
a7f7f624 642 help
3d48aab1
MW
643 Select to build support for Intel Low Power Subsystem such as
644 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
645 things like clock tree (common clock framework) and pincontrol
646 which are needed by the LPSS peripheral drivers.
3d48aab1 647
92082a88
KX
648config X86_AMD_PLATFORM_DEVICE
649 bool "AMD ACPI2Platform devices support"
650 depends on ACPI
651 select COMMON_CLK
652 select PINCTRL
a7f7f624 653 help
92082a88
KX
654 Select to interpret AMD specific ACPI device to platform device
655 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
656 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
657 implemented under PINCTRL subsystem.
658
ced3ce76
DB
659config IOSF_MBI
660 tristate "Intel SoC IOSF Sideband support for SoC platforms"
661 depends on PCI
a7f7f624 662 help
ced3ce76
DB
663 This option enables sideband register access support for Intel SoC
664 platforms. On these platforms the IOSF sideband is used in lieu of
665 MSR's for some register accesses, mostly but not limited to thermal
666 and power. Drivers may query the availability of this device to
667 determine if they need the sideband in order to work on these
668 platforms. The sideband is available on the following SoC products.
669 This list is not meant to be exclusive.
670 - BayTrail
671 - Braswell
672 - Quark
673
674 You should say Y if you are running a kernel on one of these SoC's.
675
ed2226bd
DB
676config IOSF_MBI_DEBUG
677 bool "Enable IOSF sideband access through debugfs"
678 depends on IOSF_MBI && DEBUG_FS
a7f7f624 679 help
ed2226bd
DB
680 Select this option to expose the IOSF sideband access registers (MCR,
681 MDR, MCRX) through debugfs to write and read register information from
682 different units on the SoC. This is most useful for obtaining device
683 state information for debug and analysis. As this is a general access
684 mechanism, users of this option would have specific knowledge of the
685 device they want to access.
686
687 If you don't require the option or are in doubt, say N.
688
c5c606d9
RT
689config X86_RDC321X
690 bool "RDC R-321x SoC"
506f1d07 691 depends on X86_32
c5c606d9
RT
692 depends on X86_EXTENDED_PLATFORM
693 select M486
694 select X86_REBOOTFIXUPS
a7f7f624 695 help
c5c606d9
RT
696 This option is needed for RDC R-321x system-on-chip, also known
697 as R-8610-(G).
698 If you don't have one of these chips, you should say N here.
699
e0c7ae37 700config X86_32_NON_STANDARD
9c398017
IM
701 bool "Support non-standard 32-bit SMP architectures"
702 depends on X86_32 && SMP
c5c606d9 703 depends on X86_EXTENDED_PLATFORM
a7f7f624 704 help
b5660ba7
PA
705 This option compiles in the bigsmp and STA2X11 default
706 subarchitectures. It is intended for a generic binary
707 kernel. If you select them all, kernel will probe it one by
708 one and will fallback to default.
d49c4288 709
c5c606d9 710# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 711
d949f36f 712config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 713 def_bool y
d949f36f
LT
714 # MCE code calls memory_failure():
715 depends on X86_MCE
716 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
717 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
718 depends on X86_64 || !SPARSEMEM
719 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 720
83125a3a
AR
721config STA2X11
722 bool "STA2X11 Companion Chip Support"
723 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
724 select SWIOTLB
725 select MFD_STA2X11
0145071b 726 select GPIOLIB
a7f7f624 727 help
83125a3a
AR
728 This adds support for boards based on the STA2X11 IO-Hub,
729 a.k.a. "ConneXt". The chip is used in place of the standard
730 PC chipset, so all "standard" peripherals are missing. If this
731 option is selected the kernel will still be able to boot on
732 standard PC machines.
733
82148d1d
S
734config X86_32_IRIS
735 tristate "Eurobraille/Iris poweroff module"
736 depends on X86_32
a7f7f624 737 help
82148d1d
S
738 The Iris machines from EuroBraille do not have APM or ACPI support
739 to shut themselves down properly. A special I/O sequence is
740 needed to do so, which is what this module does at
741 kernel shutdown.
742
743 This is only for Iris machines from EuroBraille.
744
745 If unused, say N.
746
ae1e9130 747config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
748 def_bool y
749 prompt "Single-depth WCHAN output"
a87d0914 750 depends on X86
a7f7f624 751 help
506f1d07
SR
752 Calculate simpler /proc/<PID>/wchan values. If this option
753 is disabled then wchan values will recurse back to the
754 caller function. This provides more accurate wchan values,
755 at the expense of slightly more scheduling overhead.
756
757 If in doubt, say "Y".
758
6276a074
BP
759menuconfig HYPERVISOR_GUEST
760 bool "Linux guest support"
a7f7f624 761 help
6276a074
BP
762 Say Y here to enable options for running Linux under various hyper-
763 visors. This option enables basic hypervisor detection and platform
764 setup.
506f1d07 765
6276a074
BP
766 If you say N, all options in this submenu will be skipped and
767 disabled, and Linux guest support won't be built in.
506f1d07 768
6276a074 769if HYPERVISOR_GUEST
506f1d07 770
e61bd94a
EPH
771config PARAVIRT
772 bool "Enable paravirtualization code"
a7f7f624 773 help
e61bd94a
EPH
774 This changes the kernel so it can modify itself when it is run
775 under a hypervisor, potentially improving performance significantly
776 over full virtualization. However, when run without a hypervisor
777 the kernel is theoretically slower and slightly larger.
778
c00a280a
JG
779config PARAVIRT_XXL
780 bool
781
6276a074
BP
782config PARAVIRT_DEBUG
783 bool "paravirt-ops debugging"
784 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 785 help
6276a074
BP
786 Enable to debug paravirt_ops internals. Specifically, BUG if
787 a paravirt_op is missing when it is called.
788
b4ecc126
JF
789config PARAVIRT_SPINLOCKS
790 bool "Paravirtualization layer for spinlocks"
6ea30386 791 depends on PARAVIRT && SMP
a7f7f624 792 help
b4ecc126
JF
793 Paravirtualized spinlocks allow a pvops backend to replace the
794 spinlock implementation with something virtualization-friendly
795 (for example, block the virtual CPU rather than spinning).
796
4c4e4f61
R
797 It has a minimal impact on native kernels and gives a nice performance
798 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 799
4c4e4f61 800 If you are unsure how to answer this question, answer Y.
b4ecc126 801
ecca2502
ZY
802config X86_HV_CALLBACK_VECTOR
803 def_bool n
804
6276a074 805source "arch/x86/xen/Kconfig"
7af192c9 806
6276a074
BP
807config KVM_GUEST
808 bool "KVM Guest support (including kvmclock)"
809 depends on PARAVIRT
810 select PARAVIRT_CLOCK
a1c4423b 811 select ARCH_CPUIDLE_HALTPOLL
b1d40575 812 select X86_HV_CALLBACK_VECTOR
6276a074 813 default y
a7f7f624 814 help
6276a074
BP
815 This option enables various optimizations for running under the KVM
816 hypervisor. It includes a paravirtualized clock, so that instead
817 of relying on a PIT (or probably other) emulation by the
818 underlying device model, the host provides the guest with
819 timing infrastructure such as time of day, and system time
506f1d07 820
a1c4423b 821config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
822 def_bool n
823 prompt "Disable host haltpoll when loading haltpoll driver"
824 help
a1c4423b
MT
825 If virtualized under KVM, disable host haltpoll.
826
7733607f
MW
827config PVH
828 bool "Support for running PVH guests"
a7f7f624 829 help
7733607f
MW
830 This option enables the PVH entry point for guest virtual machines
831 as specified in the x86/HVM direct boot ABI.
832
6276a074
BP
833config PARAVIRT_TIME_ACCOUNTING
834 bool "Paravirtual steal time accounting"
835 depends on PARAVIRT
a7f7f624 836 help
6276a074
BP
837 Select this option to enable fine granularity task steal time
838 accounting. Time spent executing other tasks in parallel with
839 the current vCPU is discounted from the vCPU power. To account for
840 that, there can be a small performance impact.
841
842 If in doubt, say N here.
843
844config PARAVIRT_CLOCK
845 bool
97349135 846
4a362601
JK
847config JAILHOUSE_GUEST
848 bool "Jailhouse non-root cell support"
abde587b 849 depends on X86_64 && PCI
87e65d05 850 select X86_PM_TIMER
a7f7f624 851 help
4a362601
JK
852 This option allows to run Linux as guest in a Jailhouse non-root
853 cell. You can leave this option disabled if you only want to start
854 Jailhouse and run Linux afterwards in the root cell.
855
ec7972c9
ZY
856config ACRN_GUEST
857 bool "ACRN Guest support"
858 depends on X86_64
498ad393 859 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
860 help
861 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
862 a flexible, lightweight reference open-source hypervisor, built with
863 real-time and safety-criticality in mind. It is built for embedded
864 IOT with small footprint and real-time features. More details can be
865 found in https://projectacrn.org/.
866
6276a074 867endif #HYPERVISOR_GUEST
97349135 868
506f1d07
SR
869source "arch/x86/Kconfig.cpu"
870
871config HPET_TIMER
3c2362e6 872 def_bool X86_64
506f1d07 873 prompt "HPET Timer Support" if X86_32
a7f7f624 874 help
8f9ca475
IM
875 Use the IA-PC HPET (High Precision Event Timer) to manage
876 time in preference to the PIT and RTC, if a HPET is
877 present.
878 HPET is the next generation timer replacing legacy 8254s.
879 The HPET provides a stable time base on SMP
880 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
881 as it is off-chip. The interface used is documented
882 in the HPET spec, revision 1.
506f1d07 883
8f9ca475
IM
884 You can safely choose Y here. However, HPET will only be
885 activated if the platform and the BIOS support this feature.
886 Otherwise the 8254 will be used for timing services.
506f1d07 887
8f9ca475 888 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
889
890config HPET_EMULATE_RTC
3c2362e6 891 def_bool y
9d8af78b 892 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 893
bb24c471 894config APB_TIMER
b03b016f
KK
895 def_bool y if X86_INTEL_MID
896 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
897 select DW_APB_TIMER
898 depends on X86_INTEL_MID && SFI
899 help
900 APB timer is the replacement for 8254, HPET on X86 MID platforms.
901 The APBT provides a stable time base on SMP
902 systems, unlike the TSC, but it is more expensive to access,
903 as it is off-chip. APB timers are always running regardless of CPU
904 C states, they are used as per CPU clockevent device when possible.
bb24c471 905
6a108a14 906# Mark as expert because too many people got it wrong.
506f1d07 907# The code disables itself when not needed.
7ae9392c
TP
908config DMI
909 default y
cf074402 910 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 911 bool "Enable DMI scanning" if EXPERT
a7f7f624 912 help
7ae9392c
TP
913 Enabled scanning of DMI to identify machine quirks. Say Y
914 here unless you have verified that your setup is not
915 affected by entries in the DMI blacklist. Required by PNP
916 BIOS code.
917
506f1d07 918config GART_IOMMU
38901f1c 919 bool "Old AMD GART IOMMU support"
2f9237d4 920 select DMA_OPS
a4ce5a48 921 select IOMMU_HELPER
506f1d07 922 select SWIOTLB
23ac4ae8 923 depends on X86_64 && PCI && AMD_NB
a7f7f624 924 help
ced3c42c
IM
925 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
926 GART based hardware IOMMUs.
927
928 The GART supports full DMA access for devices with 32-bit access
929 limitations, on systems with more than 3 GB. This is usually needed
930 for USB, sound, many IDE/SATA chipsets and some other devices.
931
932 Newer systems typically have a modern AMD IOMMU, supported via
933 the CONFIG_AMD_IOMMU=y config option.
934
935 In normal configurations this driver is only active when needed:
936 there's more than 3 GB of memory and the system contains a
937 32-bit limited device.
938
939 If unsure, say Y.
506f1d07 940
1184dc2f 941config MAXSMP
ddb0c5a6 942 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 943 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 944 select CPUMASK_OFFSTACK
a7f7f624 945 help
ddb0c5a6 946 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 947 If unsure, say N.
506f1d07 948
aec6487e
IM
949#
950# The maximum number of CPUs supported:
951#
952# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
953# and which can be configured interactively in the
954# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
955#
956# The ranges are different on 32-bit and 64-bit kernels, depending on
957# hardware capabilities and scalability features of the kernel.
958#
959# ( If MAXSMP is enabled we just use the highest possible value and disable
960# interactive configuration. )
961#
962
963config NR_CPUS_RANGE_BEGIN
a0d0bb4d 964 int
aec6487e
IM
965 default NR_CPUS_RANGE_END if MAXSMP
966 default 1 if !SMP
967 default 2
a0d0bb4d 968
aec6487e 969config NR_CPUS_RANGE_END
a0d0bb4d 970 int
aec6487e
IM
971 depends on X86_32
972 default 64 if SMP && X86_BIGSMP
973 default 8 if SMP && !X86_BIGSMP
974 default 1 if !SMP
a0d0bb4d 975
aec6487e 976config NR_CPUS_RANGE_END
a0d0bb4d 977 int
aec6487e 978 depends on X86_64
1edae1ae
SW
979 default 8192 if SMP && CPUMASK_OFFSTACK
980 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 981 default 1 if !SMP
a0d0bb4d 982
aec6487e 983config NR_CPUS_DEFAULT
a0d0bb4d
RD
984 int
985 depends on X86_32
aec6487e
IM
986 default 32 if X86_BIGSMP
987 default 8 if SMP
988 default 1 if !SMP
a0d0bb4d 989
aec6487e 990config NR_CPUS_DEFAULT
a0d0bb4d
RD
991 int
992 depends on X86_64
aec6487e
IM
993 default 8192 if MAXSMP
994 default 64 if SMP
995 default 1 if !SMP
a0d0bb4d 996
506f1d07 997config NR_CPUS
36f5101a 998 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
999 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1000 default NR_CPUS_DEFAULT
a7f7f624 1001 help
506f1d07 1002 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1003 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1004 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1005 minimum value which makes sense is 2.
1006
aec6487e
IM
1007 This is purely to save memory: each supported CPU adds about 8KB
1008 to the kernel image.
506f1d07
SR
1009
1010config SCHED_SMT
dbe73364 1011 def_bool y if SMP
506f1d07
SR
1012
1013config SCHED_MC
3c2362e6
HH
1014 def_bool y
1015 prompt "Multi-core scheduler support"
c8e56d20 1016 depends on SMP
a7f7f624 1017 help
506f1d07
SR
1018 Multi-core scheduler support improves the CPU scheduler's decision
1019 making when dealing with multi-core CPU chips at a cost of slightly
1020 increased overhead in some places. If unsure say N here.
1021
de966cf4
TC
1022config SCHED_MC_PRIO
1023 bool "CPU core priorities scheduler support"
0a21fc12
IM
1024 depends on SCHED_MC && CPU_SUP_INTEL
1025 select X86_INTEL_PSTATE
1026 select CPU_FREQ
de966cf4 1027 default y
a7f7f624 1028 help
0a21fc12
IM
1029 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1030 core ordering determined at manufacturing time, which allows
1031 certain cores to reach higher turbo frequencies (when running
1032 single threaded workloads) than others.
de966cf4 1033
0a21fc12
IM
1034 Enabling this kernel feature teaches the scheduler about
1035 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1036 scheduler's CPU selection logic accordingly, so that higher
1037 overall system performance can be achieved.
de966cf4 1038
0a21fc12 1039 This feature will have no effect on CPUs without this feature.
de966cf4 1040
0a21fc12 1041 If unsure say Y here.
5e76b2ab 1042
30b8b006 1043config UP_LATE_INIT
b03b016f
KK
1044 def_bool y
1045 depends on !SMP && X86_LOCAL_APIC
30b8b006 1046
506f1d07 1047config X86_UP_APIC
50849eef
JB
1048 bool "Local APIC support on uniprocessors" if !PCI_MSI
1049 default PCI_MSI
38a1dfda 1050 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1051 help
506f1d07
SR
1052 A local APIC (Advanced Programmable Interrupt Controller) is an
1053 integrated interrupt controller in the CPU. If you have a single-CPU
1054 system which has a processor with a local APIC, you can say Y here to
1055 enable and use it. If you say Y here even though your machine doesn't
1056 have a local APIC, then the kernel will still run with no slowdown at
1057 all. The local APIC supports CPU-generated self-interrupts (timer,
1058 performance counters), and the NMI watchdog which detects hard
1059 lockups.
1060
1061config X86_UP_IOAPIC
1062 bool "IO-APIC support on uniprocessors"
1063 depends on X86_UP_APIC
a7f7f624 1064 help
506f1d07
SR
1065 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1066 SMP-capable replacement for PC-style interrupt controllers. Most
1067 SMP systems and many recent uniprocessor systems have one.
1068
1069 If you have a single-CPU system with an IO-APIC, you can say Y here
1070 to use it. If you say Y here even though your machine doesn't have
1071 an IO-APIC, then the kernel will still run with no slowdown at all.
1072
1073config X86_LOCAL_APIC
3c2362e6 1074 def_bool y
0dbc6078 1075 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1076 select IRQ_DOMAIN_HIERARCHY
52f518a3 1077 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
506f1d07
SR
1078
1079config X86_IO_APIC
b1da1e71
JB
1080 def_bool y
1081 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1082
41b9eb26
SA
1083config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1084 bool "Reroute for broken boot IRQs"
41b9eb26 1085 depends on X86_IO_APIC
a7f7f624 1086 help
41b9eb26
SA
1087 This option enables a workaround that fixes a source of
1088 spurious interrupts. This is recommended when threaded
1089 interrupt handling is used on systems where the generation of
1090 superfluous "boot interrupts" cannot be disabled.
1091
1092 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1093 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1094 kernel does during interrupt handling). On chipsets where this
1095 boot IRQ generation cannot be disabled, this workaround keeps
1096 the original IRQ line masked so that only the equivalent "boot
1097 IRQ" is delivered to the CPUs. The workaround also tells the
1098 kernel to set up the IRQ handler on the boot IRQ line. In this
1099 way only one interrupt is delivered to the kernel. Otherwise
1100 the spurious second interrupt may cause the kernel to bring
1101 down (vital) interrupt lines.
1102
1103 Only affects "broken" chipsets. Interrupt sharing may be
1104 increased on these systems.
1105
506f1d07 1106config X86_MCE
bab9bc65 1107 bool "Machine Check / overheating reporting"
648ed940 1108 select GENERIC_ALLOCATOR
e57dbaf7 1109 default y
a7f7f624 1110 help
bab9bc65
AK
1111 Machine Check support allows the processor to notify the
1112 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1113 The action the kernel takes depends on the severity of the problem,
bab9bc65 1114 ranging from warning messages to halting the machine.
4efc0670 1115
5de97c9f
TL
1116config X86_MCELOG_LEGACY
1117 bool "Support for deprecated /dev/mcelog character device"
1118 depends on X86_MCE
a7f7f624 1119 help
5de97c9f
TL
1120 Enable support for /dev/mcelog which is needed by the old mcelog
1121 userspace logging daemon. Consider switching to the new generation
1122 rasdaemon solution.
1123
506f1d07 1124config X86_MCE_INTEL
3c2362e6
HH
1125 def_bool y
1126 prompt "Intel MCE features"
c1ebf835 1127 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1128 help
506f1d07
SR
1129 Additional support for intel specific MCE features such as
1130 the thermal monitor.
1131
1132config X86_MCE_AMD
3c2362e6
HH
1133 def_bool y
1134 prompt "AMD MCE features"
f5382de9 1135 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
a7f7f624 1136 help
506f1d07
SR
1137 Additional support for AMD specific MCE features such as
1138 the DRAM Error Threshold.
1139
4efc0670 1140config X86_ANCIENT_MCE
6fc108a0 1141 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1142 depends on X86_32 && X86_MCE
a7f7f624 1143 help
cd13adcc 1144 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1145 systems. These typically need to be enabled explicitly on the command
cd13adcc 1146 line.
4efc0670 1147
b2762686
AK
1148config X86_MCE_THRESHOLD
1149 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1150 def_bool y
b2762686 1151
ea149b36 1152config X86_MCE_INJECT
bc8e80d5 1153 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1154 tristate "Machine check injector support"
a7f7f624 1155 help
ea149b36
AK
1156 Provide support for injecting machine checks for testing purposes.
1157 If you don't know what a machine check is and you don't do kernel
1158 QA it is safe to say n.
1159
4efc0670
AK
1160config X86_THERMAL_VECTOR
1161 def_bool y
5bb38adc 1162 depends on X86_MCE_INTEL
4efc0670 1163
07dc900e 1164source "arch/x86/events/Kconfig"
e633c65a 1165
5aef51c3 1166config X86_LEGACY_VM86
1e642812 1167 bool "Legacy VM86 support"
506f1d07 1168 depends on X86_32
a7f7f624 1169 help
5aef51c3
AL
1170 This option allows user programs to put the CPU into V8086
1171 mode, which is an 80286-era approximation of 16-bit real mode.
1172
1173 Some very old versions of X and/or vbetool require this option
1174 for user mode setting. Similarly, DOSEMU will use it if
1175 available to accelerate real mode DOS programs. However, any
1176 recent version of DOSEMU, X, or vbetool should be fully
1177 functional even without kernel VM86 support, as they will all
1e642812
IM
1178 fall back to software emulation. Nevertheless, if you are using
1179 a 16-bit DOS program where 16-bit performance matters, vm86
1180 mode might be faster than emulation and you might want to
1181 enable this option.
5aef51c3 1182
1e642812
IM
1183 Note that any app that works on a 64-bit kernel is unlikely to
1184 need this option, as 64-bit kernels don't, and can't, support
1185 V8086 mode. This option is also unrelated to 16-bit protected
1186 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1187
1e642812
IM
1188 Enabling this option increases the complexity of the kernel
1189 and slows down exception handling a tiny bit.
5aef51c3 1190
1e642812 1191 If unsure, say N here.
5aef51c3
AL
1192
1193config VM86
b03b016f
KK
1194 bool
1195 default X86_LEGACY_VM86
34273f41
PA
1196
1197config X86_16BIT
1198 bool "Enable support for 16-bit segments" if EXPERT
1199 default y
a5b9e5a2 1200 depends on MODIFY_LDT_SYSCALL
a7f7f624 1201 help
34273f41
PA
1202 This option is required by programs like Wine to run 16-bit
1203 protected mode legacy code on x86 processors. Disabling
1204 this option saves about 300 bytes on i386, or around 6K text
1205 plus 16K runtime memory on x86-64,
1206
1207config X86_ESPFIX32
1208 def_bool y
1209 depends on X86_16BIT && X86_32
506f1d07 1210
197725de
PA
1211config X86_ESPFIX64
1212 def_bool y
34273f41 1213 depends on X86_16BIT && X86_64
506f1d07 1214
1ad83c85 1215config X86_VSYSCALL_EMULATION
b03b016f
KK
1216 bool "Enable vsyscall emulation" if EXPERT
1217 default y
1218 depends on X86_64
a7f7f624 1219 help
1ad83c85
AL
1220 This enables emulation of the legacy vsyscall page. Disabling
1221 it is roughly equivalent to booting with vsyscall=none, except
1222 that it will also disable the helpful warning if a program
1223 tries to use a vsyscall. With this option set to N, offending
1224 programs will just segfault, citing addresses of the form
1225 0xffffffffff600?00.
1226
1227 This option is required by many programs built before 2013, and
1228 care should be used even with newer programs if set to N.
1229
1230 Disabling this option saves about 7K of kernel size and
1231 possibly 4K of additional runtime pagetable memory.
1232
111e7b15
TG
1233config X86_IOPL_IOPERM
1234 bool "IOPERM and IOPL Emulation"
a24ca997 1235 default y
a7f7f624 1236 help
111e7b15
TG
1237 This enables the ioperm() and iopl() syscalls which are necessary
1238 for legacy applications.
1239
c8137ace
TG
1240 Legacy IOPL support is an overbroad mechanism which allows user
1241 space aside of accessing all 65536 I/O ports also to disable
1242 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1243 capabilities and permission from potentially active security
1244 modules.
1245
1246 The emulation restricts the functionality of the syscall to
1247 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1248 ability to disable interrupts from user space which would be
1249 granted if the hardware IOPL mechanism would be used.
c8137ace 1250
506f1d07
SR
1251config TOSHIBA
1252 tristate "Toshiba Laptop support"
1253 depends on X86_32
a7f7f624 1254 help
506f1d07
SR
1255 This adds a driver to safely access the System Management Mode of
1256 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1257 not work on models with a Phoenix BIOS. The System Management Mode
1258 is used to set the BIOS and power saving options on Toshiba portables.
1259
1260 For information on utilities to make use of this driver see the
1261 Toshiba Linux utilities web site at:
1262 <http://www.buzzard.org.uk/toshiba/>.
1263
1264 Say Y if you intend to run this kernel on a Toshiba portable.
1265 Say N otherwise.
1266
1267config I8K
039ae585 1268 tristate "Dell i8k legacy laptop support"
949a9d70 1269 select HWMON
039ae585 1270 select SENSORS_DELL_SMM
a7f7f624 1271 help
039ae585
PR
1272 This option enables legacy /proc/i8k userspace interface in hwmon
1273 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1274 temperature and allows controlling fan speeds of Dell laptops via
1275 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1276 it reports also power and hotkey status. For fan speed control is
1277 needed userspace package i8kutils.
1278
1279 Say Y if you intend to run this kernel on old Dell laptops or want to
1280 use userspace package i8kutils.
506f1d07
SR
1281 Say N otherwise.
1282
1283config X86_REBOOTFIXUPS
9ba16087
JB
1284 bool "Enable X86 board specific fixups for reboot"
1285 depends on X86_32
a7f7f624 1286 help
506f1d07
SR
1287 This enables chipset and/or board specific fixups to be done
1288 in order to get reboot to work correctly. This is only needed on
1289 some combinations of hardware and BIOS. The symptom, for which
1290 this config is intended, is when reboot ends with a stalled/hung
1291 system.
1292
1293 Currently, the only fixup is for the Geode machines using
5e3a77e9 1294 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1295
1296 Say Y if you want to enable the fixup. Currently, it's safe to
1297 enable this option even if you don't need it.
1298 Say N otherwise.
1299
1300config MICROCODE
9a2bc335
BP
1301 bool "CPU microcode loading support"
1302 default y
80030e3d 1303 depends on CPU_SUP_AMD || CPU_SUP_INTEL
a7f7f624 1304 help
506f1d07 1305 If you say Y here, you will be able to update the microcode on
5f9c01aa
BP
1306 Intel and AMD processors. The Intel support is for the IA32 family,
1307 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1308 AMD support is for families 0x10 and later. You will obviously need
1309 the actual microcode binary data itself which is not shipped with
1310 the Linux kernel.
1311
1312 The preferred method to load microcode from a detached initrd is described
cb1aaebe 1313 in Documentation/x86/microcode.rst. For that you need to enable
5f9c01aa
BP
1314 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1315 initrd for microcode blobs.
1316
c508c46e
BG
1317 In addition, you can build the microcode into the kernel. For that you
1318 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1319 config option.
506f1d07 1320
8d86f390 1321config MICROCODE_INTEL
e43f6e67 1322 bool "Intel microcode loading support"
8f9ca475
IM
1323 depends on MICROCODE
1324 default MICROCODE
a7f7f624 1325 help
8f9ca475
IM
1326 This options enables microcode patch loading support for Intel
1327 processors.
1328
b8989db9
A
1329 For the current Intel microcode data package go to
1330 <https://downloadcenter.intel.com> and search for
1331 'Linux Processor Microcode Data File'.
8d86f390 1332
80cc9f10 1333config MICROCODE_AMD
e43f6e67 1334 bool "AMD microcode loading support"
8f9ca475 1335 depends on MICROCODE
a7f7f624 1336 help
8f9ca475
IM
1337 If you select this option, microcode patch loading support for AMD
1338 processors will be enabled.
80cc9f10 1339
8f9ca475 1340config MICROCODE_OLD_INTERFACE
c02f48e0
BP
1341 bool "Ancient loading interface (DEPRECATED)"
1342 default n
506f1d07 1343 depends on MICROCODE
a7f7f624 1344 help
c02f48e0
BP
1345 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1346 which was used by userspace tools like iucode_tool and microcode.ctl.
1347 It is inadequate because it runs too late to be able to properly
1348 load microcode on a machine and it needs special tools. Instead, you
1349 should've switched to the early loading method with the initrd or
cb1aaebe 1350 builtin microcode by now: Documentation/x86/microcode.rst
506f1d07
SR
1351
1352config X86_MSR
1353 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1354 help
506f1d07
SR
1355 This device gives privileged processes access to the x86
1356 Model-Specific Registers (MSRs). It is a character device with
1357 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1358 MSR accesses are directed to a specific CPU on multi-processor
1359 systems.
1360
1361config X86_CPUID
1362 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1363 help
506f1d07
SR
1364 This device gives processes access to the x86 CPUID instruction to
1365 be executed on a specific processor. It is a character device
1366 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1367 /dev/cpu/31/cpuid.
1368
1369choice
1370 prompt "High Memory Support"
6fc108a0 1371 default HIGHMEM4G
506f1d07
SR
1372 depends on X86_32
1373
1374config NOHIGHMEM
1375 bool "off"
a7f7f624 1376 help
506f1d07
SR
1377 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1378 However, the address space of 32-bit x86 processors is only 4
1379 Gigabytes large. That means that, if you have a large amount of
1380 physical memory, not all of it can be "permanently mapped" by the
1381 kernel. The physical memory that's not permanently mapped is called
1382 "high memory".
1383
1384 If you are compiling a kernel which will never run on a machine with
1385 more than 1 Gigabyte total physical RAM, answer "off" here (default
1386 choice and suitable for most users). This will result in a "3GB/1GB"
1387 split: 3GB are mapped so that each process sees a 3GB virtual memory
1388 space and the remaining part of the 4GB virtual memory space is used
1389 by the kernel to permanently map as much physical memory as
1390 possible.
1391
1392 If the machine has between 1 and 4 Gigabytes physical RAM, then
1393 answer "4GB" here.
1394
1395 If more than 4 Gigabytes is used then answer "64GB" here. This
1396 selection turns Intel PAE (Physical Address Extension) mode on.
1397 PAE implements 3-level paging on IA32 processors. PAE is fully
1398 supported by Linux, PAE mode is implemented on all recent Intel
1399 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1400 then the kernel will not boot on CPUs that don't support PAE!
1401
1402 The actual amount of total physical memory will either be
1403 auto detected or can be forced by using a kernel command line option
1404 such as "mem=256M". (Try "man bootparam" or see the documentation of
1405 your boot loader (lilo or loadlin) about how to pass options to the
1406 kernel at boot time.)
1407
1408 If unsure, say "off".
1409
1410config HIGHMEM4G
1411 bool "4GB"
a7f7f624 1412 help
506f1d07
SR
1413 Select this if you have a 32-bit processor and between 1 and 4
1414 gigabytes of physical RAM.
1415
1416config HIGHMEM64G
1417 bool "64GB"
69b8d3fc 1418 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
506f1d07 1419 select X86_PAE
a7f7f624 1420 help
506f1d07
SR
1421 Select this if you have a 32-bit processor and more than 4
1422 gigabytes of physical RAM.
1423
1424endchoice
1425
1426choice
6a108a14 1427 prompt "Memory split" if EXPERT
506f1d07
SR
1428 default VMSPLIT_3G
1429 depends on X86_32
a7f7f624 1430 help
506f1d07
SR
1431 Select the desired split between kernel and user memory.
1432
1433 If the address range available to the kernel is less than the
1434 physical memory installed, the remaining memory will be available
1435 as "high memory". Accessing high memory is a little more costly
1436 than low memory, as it needs to be mapped into the kernel first.
1437 Note that increasing the kernel address space limits the range
1438 available to user programs, making the address space there
1439 tighter. Selecting anything other than the default 3G/1G split
1440 will also likely make your kernel incompatible with binary-only
1441 kernel modules.
1442
1443 If you are not absolutely sure what you are doing, leave this
1444 option alone!
1445
1446 config VMSPLIT_3G
1447 bool "3G/1G user/kernel split"
1448 config VMSPLIT_3G_OPT
1449 depends on !X86_PAE
1450 bool "3G/1G user/kernel split (for full 1G low memory)"
1451 config VMSPLIT_2G
1452 bool "2G/2G user/kernel split"
1453 config VMSPLIT_2G_OPT
1454 depends on !X86_PAE
1455 bool "2G/2G user/kernel split (for full 2G low memory)"
1456 config VMSPLIT_1G
1457 bool "1G/3G user/kernel split"
1458endchoice
1459
1460config PAGE_OFFSET
1461 hex
1462 default 0xB0000000 if VMSPLIT_3G_OPT
1463 default 0x80000000 if VMSPLIT_2G
1464 default 0x78000000 if VMSPLIT_2G_OPT
1465 default 0x40000000 if VMSPLIT_1G
1466 default 0xC0000000
1467 depends on X86_32
1468
1469config HIGHMEM
3c2362e6 1470 def_bool y
506f1d07 1471 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1472
1473config X86_PAE
9ba16087 1474 bool "PAE (Physical Address Extension) Support"
506f1d07 1475 depends on X86_32 && !HIGHMEM4G
d4a451d5 1476 select PHYS_ADDR_T_64BIT
9d99c712 1477 select SWIOTLB
a7f7f624 1478 help
506f1d07
SR
1479 PAE is required for NX support, and furthermore enables
1480 larger swapspace support for non-overcommit purposes. It
1481 has the cost of more pagetable lookup overhead, and also
1482 consumes more pagetable space per process.
1483
77ef56e4
KS
1484config X86_5LEVEL
1485 bool "Enable 5-level page tables support"
18ec1eaf 1486 default y
eedb92ab 1487 select DYNAMIC_MEMORY_LAYOUT
162434e7 1488 select SPARSEMEM_VMEMMAP
77ef56e4 1489 depends on X86_64
a7f7f624 1490 help
77ef56e4
KS
1491 5-level paging enables access to larger address space:
1492 upto 128 PiB of virtual address space and 4 PiB of
1493 physical address space.
1494
1495 It will be supported by future Intel CPUs.
1496
6657fca0
KS
1497 A kernel with the option enabled can be booted on machines that
1498 support 4- or 5-level paging.
77ef56e4 1499
cb1aaebe 1500 See Documentation/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1501 information.
1502
1503 Say N if unsure.
1504
10971ab2 1505config X86_DIRECT_GBPAGES
e5008abe 1506 def_bool y
2e1da13f 1507 depends on X86_64
a7f7f624 1508 help
10971ab2
IM
1509 Certain kernel features effectively disable kernel
1510 linear 1 GB mappings (even if the CPU otherwise
1511 supports them), so don't confuse the user by printing
1512 that we have them enabled.
9e899816 1513
5c280cf6
TG
1514config X86_CPA_STATISTICS
1515 bool "Enable statistic for Change Page Attribute"
1516 depends on DEBUG_FS
a7f7f624 1517 help
b75baaf3 1518 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1519 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1520 page mappings when mapping protections are changed.
1521
7744ccdb
TL
1522config AMD_MEM_ENCRYPT
1523 bool "AMD Secure Memory Encryption (SME) support"
1524 depends on X86_64 && CPU_SUP_AMD
82fef0ad 1525 select DMA_COHERENT_POOL
94d49eb3 1526 select DYNAMIC_PHYSICAL_MASK
ce9084ba 1527 select ARCH_USE_MEMREMAP_PROT
9087c375 1528 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
597cfe48 1529 select INSTRUCTION_DECODER
a7f7f624 1530 help
7744ccdb
TL
1531 Say yes to enable support for the encryption of system memory.
1532 This requires an AMD processor that supports Secure Memory
1533 Encryption (SME).
1534
1535config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1536 bool "Activate AMD Secure Memory Encryption (SME) by default"
1537 default y
1538 depends on AMD_MEM_ENCRYPT
a7f7f624 1539 help
7744ccdb
TL
1540 Say yes to have system memory encrypted by default if running on
1541 an AMD processor that supports Secure Memory Encryption (SME).
1542
1543 If set to Y, then the encryption of system memory can be
1544 deactivated with the mem_encrypt=off command line option.
1545
1546 If set to N, then the encryption of system memory can be
1547 activated with the mem_encrypt=on command line option.
1548
506f1d07
SR
1549# Common NUMA Features
1550config NUMA
e133f6ea 1551 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1552 depends on SMP
b5660ba7
PA
1553 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1554 default y if X86_BIGSMP
a7f7f624 1555 help
e133f6ea 1556 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1557
506f1d07
SR
1558 The kernel will try to allocate memory used by a CPU on the
1559 local memory controller of the CPU and add some more
1560 NUMA awareness to the kernel.
1561
c280ea5e 1562 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1563 (or later), AMD Opteron, or EM64T NUMA.
1564
b5660ba7 1565 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1566 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1567
1568 Otherwise, you should say N.
506f1d07 1569
eec1d4fa 1570config AMD_NUMA
3c2362e6
HH
1571 def_bool y
1572 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1573 depends on X86_64 && NUMA && PCI
a7f7f624 1574 help
eec1d4fa
HR
1575 Enable AMD NUMA node topology detection. You should say Y here if
1576 you have a multi processor AMD system. This uses an old method to
1577 read the NUMA configuration directly from the builtin Northbridge
1578 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1579 which also takes priority if both are compiled in.
506f1d07
SR
1580
1581config X86_64_ACPI_NUMA
3c2362e6
HH
1582 def_bool y
1583 prompt "ACPI NUMA detection"
506f1d07
SR
1584 depends on X86_64 && NUMA && ACPI && PCI
1585 select ACPI_NUMA
a7f7f624 1586 help
506f1d07
SR
1587 Enable ACPI SRAT based node topology detection.
1588
1589config NUMA_EMU
1590 bool "NUMA emulation"
1b7e03ef 1591 depends on NUMA
a7f7f624 1592 help
506f1d07
SR
1593 Enable NUMA emulation. A flat machine will be split
1594 into virtual nodes when booted with "numa=fake=N", where N is the
1595 number of nodes. This is only useful for debugging.
1596
1597config NODES_SHIFT
d25e26b6 1598 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1599 range 1 10
1600 default "10" if MAXSMP
506f1d07 1601 default "6" if X86_64
506f1d07
SR
1602 default "3"
1603 depends on NEED_MULTIPLE_NODES
a7f7f624 1604 help
1184dc2f 1605 Specify the maximum number of NUMA Nodes available on the target
692105b8 1606 system. Increases memory reserved to accommodate various tables.
506f1d07 1607
506f1d07
SR
1608config ARCH_FLATMEM_ENABLE
1609 def_bool y
3b16651f 1610 depends on X86_32 && !NUMA
506f1d07 1611
506f1d07
SR
1612config ARCH_SPARSEMEM_ENABLE
1613 def_bool y
6ea30386 1614 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1615 select SPARSEMEM_STATIC if X86_32
1616 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1617
3b16651f 1618config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1619 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1620
506f1d07
SR
1621config ARCH_SELECT_MEMORY_MODEL
1622 def_bool y
b263295d 1623 depends on ARCH_SPARSEMEM_ENABLE
506f1d07
SR
1624
1625config ARCH_MEMORY_PROBE
a0842b70 1626 bool "Enable sysfs memory/probe interface"
3120e25e 1627 depends on X86_64 && MEMORY_HOTPLUG
a0842b70
TK
1628 help
1629 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1630 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1631 If you are unsure how to answer this question, answer N.
506f1d07 1632
3b16651f
TH
1633config ARCH_PROC_KCORE_TEXT
1634 def_bool y
1635 depends on X86_64 && PROC_KCORE
1636
a29815a3 1637config ILLEGAL_POINTER_VALUE
b03b016f
KK
1638 hex
1639 default 0 if X86_32
1640 default 0xdead000000000000 if X86_64
a29815a3 1641
7a67832c
DW
1642config X86_PMEM_LEGACY_DEVICE
1643 bool
1644
ec776ef6 1645config X86_PMEM_LEGACY
7a67832c 1646 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1647 depends on PHYS_ADDR_T_64BIT
1648 depends on BLK_DEV
7a67832c 1649 select X86_PMEM_LEGACY_DEVICE
7b27a862 1650 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1651 select LIBNVDIMM
ec776ef6
CH
1652 help
1653 Treat memory marked using the non-standard e820 type of 12 as used
1654 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1655 The kernel will offer these regions to the 'pmem' driver so
1656 they can be used for persistent storage.
1657
1658 Say Y if unsure.
1659
506f1d07
SR
1660config HIGHPTE
1661 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1662 depends on HIGHMEM
a7f7f624 1663 help
506f1d07
SR
1664 The VM uses one page table entry for each page of physical memory.
1665 For systems with a lot of RAM, this can be wasteful of precious
1666 low memory. Setting this option will put user-space page table
1667 entries in high memory.
1668
9f077871 1669config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1670 bool "Check for low memory corruption"
a7f7f624 1671 help
8f9ca475
IM
1672 Periodically check for memory corruption in low memory, which
1673 is suspected to be caused by BIOS. Even when enabled in the
1674 configuration, it is disabled at runtime. Enable it by
1675 setting "memory_corruption_check=1" on the kernel command
1676 line. By default it scans the low 64k of memory every 60
1677 seconds; see the memory_corruption_check_size and
1678 memory_corruption_check_period parameters in
8c27ceff 1679 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1680
1681 When enabled with the default parameters, this option has
1682 almost no overhead, as it reserves a relatively small amount
1683 of memory and scans it infrequently. It both detects corruption
1684 and prevents it from affecting the running system.
1685
1686 It is, however, intended as a diagnostic tool; if repeatable
1687 BIOS-originated corruption always affects the same memory,
1688 you can use memmap= to prevent the kernel from using that
1689 memory.
9f077871 1690
c885df50 1691config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1692 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1693 depends on X86_CHECK_BIOS_CORRUPTION
1694 default y
a7f7f624 1695 help
8f9ca475
IM
1696 Set whether the default state of memory_corruption_check is
1697 on or off.
c885df50 1698
9ea77bdb 1699config X86_RESERVE_LOW
d0cd7425
PA
1700 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1701 default 64
1702 range 4 640
a7f7f624 1703 help
d0cd7425
PA
1704 Specify the amount of low memory to reserve for the BIOS.
1705
1706 The first page contains BIOS data structures that the kernel
1707 must not use, so that page must always be reserved.
1708
1709 By default we reserve the first 64K of physical RAM, as a
1710 number of BIOSes are known to corrupt that memory range
1711 during events such as suspend/resume or monitor cable
1712 insertion, so it must not be used by the kernel.
fc381519 1713
d0cd7425
PA
1714 You can set this to 4 if you are absolutely sure that you
1715 trust the BIOS to get all its memory reservations and usages
1716 right. If you know your BIOS have problems beyond the
1717 default 64K area, you can set this to 640 to avoid using the
1718 entire low memory range.
fc381519 1719
d0cd7425
PA
1720 If you have doubts about the BIOS (e.g. suspend/resume does
1721 not work or there's kernel crashes after certain hardware
1722 hotplug events) then you might want to enable
1723 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1724 typical corruption patterns.
fc381519 1725
d0cd7425 1726 Leave this to the default value of 64 if you are unsure.
fc381519 1727
506f1d07
SR
1728config MATH_EMULATION
1729 bool
a5b9e5a2 1730 depends on MODIFY_LDT_SYSCALL
87d6021b 1731 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1732 help
506f1d07
SR
1733 Linux can emulate a math coprocessor (used for floating point
1734 operations) if you don't have one. 486DX and Pentium processors have
1735 a math coprocessor built in, 486SX and 386 do not, unless you added
1736 a 487DX or 387, respectively. (The messages during boot time can
1737 give you some hints here ["man dmesg"].) Everyone needs either a
1738 coprocessor or this emulation.
1739
1740 If you don't have a math coprocessor, you need to say Y here; if you
1741 say Y here even though you have a coprocessor, the coprocessor will
1742 be used nevertheless. (This behavior can be changed with the kernel
1743 command line option "no387", which comes handy if your coprocessor
1744 is broken. Try "man bootparam" or see the documentation of your boot
1745 loader (lilo or loadlin) about how to pass options to the kernel at
1746 boot time.) This means that it is a good idea to say Y here if you
1747 intend to use this kernel on different machines.
1748
1749 More information about the internals of the Linux math coprocessor
1750 emulation can be found in <file:arch/x86/math-emu/README>.
1751
1752 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1753 kernel, it won't hurt.
1754
1755config MTRR
6fc108a0 1756 def_bool y
6a108a14 1757 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1758 help
506f1d07
SR
1759 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1760 the Memory Type Range Registers (MTRRs) may be used to control
1761 processor access to memory ranges. This is most useful if you have
1762 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1763 allows bus write transfers to be combined into a larger transfer
1764 before bursting over the PCI/AGP bus. This can increase performance
1765 of image write operations 2.5 times or more. Saying Y here creates a
1766 /proc/mtrr file which may be used to manipulate your processor's
1767 MTRRs. Typically the X server should use this.
1768
1769 This code has a reasonably generic interface so that similar
1770 control registers on other processors can be easily supported
1771 as well:
1772
1773 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1774 Registers (ARRs) which provide a similar functionality to MTRRs. For
1775 these, the ARRs are used to emulate the MTRRs.
1776 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1777 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1778 write-combining. All of these processors are supported by this code
1779 and it makes sense to say Y here if you have one of them.
1780
1781 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1782 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1783 can lead to all sorts of problems, so it's good to say Y here.
1784
1785 You can safely say Y even if your machine doesn't have MTRRs, you'll
1786 just add about 9 KB to your kernel.
1787
cb1aaebe 1788 See <file:Documentation/x86/mtrr.rst> for more information.
506f1d07 1789
95ffa243 1790config MTRR_SANITIZER
2ffb3501 1791 def_bool y
95ffa243
YL
1792 prompt "MTRR cleanup support"
1793 depends on MTRR
a7f7f624 1794 help
aba3728c
TG
1795 Convert MTRR layout from continuous to discrete, so X drivers can
1796 add writeback entries.
95ffa243 1797
aba3728c 1798 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1799 The largest mtrr entry size for a continuous block can be set with
aba3728c 1800 mtrr_chunk_size.
95ffa243 1801
2ffb3501 1802 If unsure, say Y.
95ffa243
YL
1803
1804config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1805 int "MTRR cleanup enable value (0-1)"
1806 range 0 1
1807 default "0"
95ffa243 1808 depends on MTRR_SANITIZER
a7f7f624 1809 help
f5098d62 1810 Enable mtrr cleanup default value
95ffa243 1811
12031a62
YL
1812config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1813 int "MTRR cleanup spare reg num (0-7)"
1814 range 0 7
1815 default "1"
1816 depends on MTRR_SANITIZER
a7f7f624 1817 help
12031a62 1818 mtrr cleanup spare entries default, it can be changed via
aba3728c 1819 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1820
2e5d9c85 1821config X86_PAT
6fc108a0 1822 def_bool y
6a108a14 1823 prompt "x86 PAT support" if EXPERT
2a8a2719 1824 depends on MTRR
a7f7f624 1825 help
2e5d9c85 1826 Use PAT attributes to setup page level cache control.
042b78e4 1827
2e5d9c85 1828 PATs are the modern equivalents of MTRRs and are much more
1829 flexible than MTRRs.
1830
1831 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1832 spontaneous reboots) or a non-working video driver.
2e5d9c85 1833
1834 If unsure, say Y.
1835
46cf98cd
VP
1836config ARCH_USES_PG_UNCACHED
1837 def_bool y
1838 depends on X86_PAT
1839
628c6246
PA
1840config ARCH_RANDOM
1841 def_bool y
1842 prompt "x86 architectural random number generator" if EXPERT
a7f7f624 1843 help
628c6246
PA
1844 Enable the x86 architectural RDRAND instruction
1845 (Intel Bull Mountain technology) to generate random numbers.
1846 If supported, this is a high bandwidth, cryptographically
1847 secure hardware random number generator.
1848
51ae4a2d
PA
1849config X86_SMAP
1850 def_bool y
1851 prompt "Supervisor Mode Access Prevention" if EXPERT
a7f7f624 1852 help
51ae4a2d
PA
1853 Supervisor Mode Access Prevention (SMAP) is a security
1854 feature in newer Intel processors. There is a small
1855 performance cost if this enabled and turned on; there is
1856 also a small increase in the kernel size if this is enabled.
1857
1858 If unsure, say Y.
1859
b971880f 1860config X86_UMIP
796ebc81 1861 def_bool y
b971880f 1862 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1863 help
b971880f
BM
1864 User Mode Instruction Prevention (UMIP) is a security feature in
1865 some x86 processors. If enabled, a general protection fault is
1866 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1867 executed in user mode. These instructions unnecessarily expose
1868 information about the hardware state.
796ebc81
RN
1869
1870 The vast majority of applications do not use these instructions.
1871 For the very few that do, software emulation is provided in
1872 specific cases in protected and virtual-8086 modes. Emulated
1873 results are dummy.
aa35f896 1874
35e97790 1875config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1876 prompt "Memory Protection Keys"
35e97790 1877 def_bool y
284244a9 1878 # Note: only available in 64-bit mode
38f3e775 1879 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1880 select ARCH_USES_HIGH_VMA_FLAGS
1881 select ARCH_HAS_PKEYS
a7f7f624 1882 help
284244a9
DH
1883 Memory Protection Keys provides a mechanism for enforcing
1884 page-based protections, but without requiring modification of the
1885 page tables when an application changes protection domains.
1886
1eecbcdc 1887 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1888
1889 If unsure, say y.
35e97790 1890
db616173
MH
1891choice
1892 prompt "TSX enable mode"
1893 depends on CPU_SUP_INTEL
1894 default X86_INTEL_TSX_MODE_OFF
1895 help
1896 Intel's TSX (Transactional Synchronization Extensions) feature
1897 allows to optimize locking protocols through lock elision which
1898 can lead to a noticeable performance boost.
1899
1900 On the other hand it has been shown that TSX can be exploited
1901 to form side channel attacks (e.g. TAA) and chances are there
1902 will be more of those attacks discovered in the future.
1903
1904 Therefore TSX is not enabled by default (aka tsx=off). An admin
1905 might override this decision by tsx=on the command line parameter.
1906 Even with TSX enabled, the kernel will attempt to enable the best
1907 possible TAA mitigation setting depending on the microcode available
1908 for the particular machine.
1909
1910 This option allows to set the default tsx mode between tsx=on, =off
1911 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1912 details.
1913
1914 Say off if not sure, auto if TSX is in use but it should be used on safe
1915 platforms or on if TSX is in use and the security aspect of tsx is not
1916 relevant.
1917
1918config X86_INTEL_TSX_MODE_OFF
1919 bool "off"
1920 help
1921 TSX is disabled if possible - equals to tsx=off command line parameter.
1922
1923config X86_INTEL_TSX_MODE_ON
1924 bool "on"
1925 help
1926 TSX is always enabled on TSX capable HW - equals the tsx=on command
1927 line parameter.
1928
1929config X86_INTEL_TSX_MODE_AUTO
1930 bool "auto"
1931 help
1932 TSX is enabled on TSX capable HW that is believed to be safe against
1933 side channel attacks- equals the tsx=auto command line parameter.
1934endchoice
1935
e7e05452
SC
1936config X86_SGX
1937 bool "Software Guard eXtensions (SGX)"
1938 depends on X86_64 && CPU_SUP_INTEL
1939 depends on CRYPTO=y
1940 depends on CRYPTO_SHA256=y
1941 select SRCU
1942 select MMU_NOTIFIER
1943 help
1944 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1945 that can be used by applications to set aside private regions of code
1946 and data, referred to as enclaves. An enclave's private memory can
1947 only be accessed by code running within the enclave. Accesses from
1948 outside the enclave, including other enclaves, are disallowed by
1949 hardware.
1950
1951 If unsure, say N.
1952
506f1d07 1953config EFI
9ba16087 1954 bool "EFI runtime service support"
5b83683f 1955 depends on ACPI
f6ce5002 1956 select UCS2_STRING
022ee6c5 1957 select EFI_RUNTIME_WRAPPERS
a7f7f624 1958 help
8f9ca475
IM
1959 This enables the kernel to use EFI runtime services that are
1960 available (such as the EFI variable services).
506f1d07 1961
8f9ca475
IM
1962 This option is only useful on systems that have EFI firmware.
1963 In addition, you should use the latest ELILO loader available
1964 at <http://elilo.sourceforge.net> in order to take advantage
1965 of EFI runtime services. However, even with this option, the
1966 resultant kernel should continue to boot on existing non-EFI
1967 platforms.
506f1d07 1968
291f3632 1969config EFI_STUB
8f24f8c2
AB
1970 bool "EFI stub support"
1971 depends on EFI && !X86_USE_3DNOW
1972 depends on $(cc-option,-mabi=ms) || X86_32
1973 select RELOCATABLE
a7f7f624 1974 help
8f24f8c2 1975 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
1976 by EFI firmware without the use of a bootloader.
1977
4f4cfa6c 1978 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1979
7d453eee
MF
1980config EFI_MIXED
1981 bool "EFI mixed-mode support"
1982 depends on EFI_STUB && X86_64
a7f7f624 1983 help
7d453eee
MF
1984 Enabling this feature allows a 64-bit kernel to be booted
1985 on a 32-bit firmware, provided that your CPU supports 64-bit
1986 mode.
1987
1988 Note that it is not possible to boot a mixed-mode enabled
1989 kernel via the EFI boot stub - a bootloader that supports
1990 the EFI handover protocol must be used.
1991
1992 If unsure, say N.
1993
8636a1f9 1994source "kernel/Kconfig.hz"
506f1d07
SR
1995
1996config KEXEC
1997 bool "kexec system call"
2965faa5 1998 select KEXEC_CORE
a7f7f624 1999 help
506f1d07
SR
2000 kexec is a system call that implements the ability to shutdown your
2001 current kernel, and to start another kernel. It is like a reboot
2002 but it is independent of the system firmware. And like a reboot
2003 you can start any kernel with it, not just Linux.
2004
2005 The name comes from the similarity to the exec system call.
2006
2007 It is an ongoing process to be certain the hardware in a machine
2008 is properly shutdown, so do not be surprised if this code does not
bf220695
GU
2009 initially work for you. As of this writing the exact hardware
2010 interface is strongly in flux, so no good recommendation can be
2011 made.
506f1d07 2012
74ca317c
VG
2013config KEXEC_FILE
2014 bool "kexec file based system call"
2965faa5 2015 select KEXEC_CORE
74ca317c 2016 select BUILD_BIN2C
74ca317c
VG
2017 depends on X86_64
2018 depends on CRYPTO=y
2019 depends on CRYPTO_SHA256=y
a7f7f624 2020 help
74ca317c
VG
2021 This is new version of kexec system call. This system call is
2022 file based and takes file descriptors as system call argument
2023 for kernel and initramfs as opposed to list of segments as
2024 accepted by previous system call.
2025
b799a09f
AT
2026config ARCH_HAS_KEXEC_PURGATORY
2027 def_bool KEXEC_FILE
2028
99d5cadf 2029config KEXEC_SIG
8e7d8381 2030 bool "Verify kernel signature during kexec_file_load() syscall"
74ca317c 2031 depends on KEXEC_FILE
a7f7f624 2032 help
d8eb8940 2033
99d5cadf
JB
2034 This option makes the kexec_file_load() syscall check for a valid
2035 signature of the kernel image. The image can still be loaded without
2036 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2037 there's a signature that we can check, then it must be valid.
2038
2039 In addition to this option, you need to enable signature
d8eb8940
BP
2040 verification for the corresponding kernel image type being
2041 loaded in order for this to work.
8e7d8381 2042
99d5cadf
JB
2043config KEXEC_SIG_FORCE
2044 bool "Require a valid signature in kexec_file_load() syscall"
2045 depends on KEXEC_SIG
a7f7f624 2046 help
99d5cadf
JB
2047 This option makes kernel signature verification mandatory for
2048 the kexec_file_load() syscall.
2049
8e7d8381
VG
2050config KEXEC_BZIMAGE_VERIFY_SIG
2051 bool "Enable bzImage signature verification support"
99d5cadf 2052 depends on KEXEC_SIG
8e7d8381
VG
2053 depends on SIGNED_PE_FILE_VERIFICATION
2054 select SYSTEM_TRUSTED_KEYRING
a7f7f624 2055 help
8e7d8381
VG
2056 Enable bzImage signature verification support.
2057
506f1d07 2058config CRASH_DUMP
04b69447 2059 bool "kernel crash dumps"
506f1d07 2060 depends on X86_64 || (X86_32 && HIGHMEM)
a7f7f624 2061 help
506f1d07
SR
2062 Generate crash dump after being started by kexec.
2063 This should be normally only set in special crash dump kernels
2064 which are loaded in the main kernel with kexec-tools into
2065 a specially reserved region and then later executed after
2066 a crash by kdump/kexec. The crash dump kernel must be compiled
2067 to a memory address not used by the main kernel or BIOS using
2068 PHYSICAL_START, or it must be built as a relocatable image
2069 (CONFIG_RELOCATABLE=y).
330d4810 2070 For more details see Documentation/admin-guide/kdump/kdump.rst
506f1d07 2071
3ab83521 2072config KEXEC_JUMP
6ea30386 2073 bool "kexec jump"
fee7b0d8 2074 depends on KEXEC && HIBERNATION
a7f7f624 2075 help
89081d17
HY
2076 Jump between original kernel and kexeced kernel and invoke
2077 code in physical address mode via KEXEC
3ab83521 2078
506f1d07 2079config PHYSICAL_START
6a108a14 2080 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2081 default "0x1000000"
a7f7f624 2082 help
506f1d07
SR
2083 This gives the physical address where the kernel is loaded.
2084
2085 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2086 bzImage will decompress itself to above physical address and
2087 run from there. Otherwise, bzImage will run from the address where
2088 it has been loaded by the boot loader and will ignore above physical
2089 address.
2090
2091 In normal kdump cases one does not have to set/change this option
2092 as now bzImage can be compiled as a completely relocatable image
2093 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2094 address. This option is mainly useful for the folks who don't want
2095 to use a bzImage for capturing the crash dump and want to use a
2096 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2097 to be specifically compiled to run from a specific memory area
2098 (normally a reserved region) and this option comes handy.
2099
ceefccc9
PA
2100 So if you are using bzImage for capturing the crash dump,
2101 leave the value here unchanged to 0x1000000 and set
2102 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2103 for capturing the crash dump change this value to start of
2104 the reserved region. In other words, it can be set based on
2105 the "X" value as specified in the "crashkernel=YM@XM"
2106 command line boot parameter passed to the panic-ed
330d4810 2107 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2108 for more details about crash dumps.
506f1d07
SR
2109
2110 Usage of bzImage for capturing the crash dump is recommended as
2111 one does not have to build two kernels. Same kernel can be used
2112 as production kernel and capture kernel. Above option should have
2113 gone away after relocatable bzImage support is introduced. But it
2114 is present because there are users out there who continue to use
2115 vmlinux for dump capture. This option should go away down the
2116 line.
2117
2118 Don't change this unless you know what you are doing.
2119
2120config RELOCATABLE
26717808
PA
2121 bool "Build a relocatable kernel"
2122 default y
a7f7f624 2123 help
506f1d07
SR
2124 This builds a kernel image that retains relocation information
2125 so it can be loaded someplace besides the default 1MB.
2126 The relocations tend to make the kernel binary about 10% larger,
2127 but are discarded at runtime.
2128
2129 One use is for the kexec on panic case where the recovery kernel
2130 must live at a different physical address than the primary
2131 kernel.
2132
2133 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2134 it has been loaded at and the compile time physical address
8ab3820f 2135 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2136
8ab3820f 2137config RANDOMIZE_BASE
e8581e3d 2138 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2139 depends on RELOCATABLE
6807c846 2140 default y
a7f7f624 2141 help
e8581e3d
BH
2142 In support of Kernel Address Space Layout Randomization (KASLR),
2143 this randomizes the physical address at which the kernel image
2144 is decompressed and the virtual address where the kernel
2145 image is mapped, as a security feature that deters exploit
2146 attempts relying on knowledge of the location of kernel
2147 code internals.
2148
ed9f007e
KC
2149 On 64-bit, the kernel physical and virtual addresses are
2150 randomized separately. The physical address will be anywhere
2151 between 16MB and the top of physical memory (up to 64TB). The
2152 virtual address will be randomized from 16MB up to 1GB (9 bits
2153 of entropy). Note that this also reduces the memory space
2154 available to kernel modules from 1.5GB to 1GB.
2155
2156 On 32-bit, the kernel physical and virtual addresses are
2157 randomized together. They will be randomized from 16MB up to
2158 512MB (8 bits of entropy).
e8581e3d
BH
2159
2160 Entropy is generated using the RDRAND instruction if it is
2161 supported. If RDTSC is supported, its value is mixed into
2162 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2163 supported, then entropy is read from the i8254 timer. The
2164 usable entropy is limited by the kernel being built using
2165 2GB addressing, and that PHYSICAL_ALIGN must be at a
2166 minimum of 2MB. As a result, only 10 bits of entropy are
2167 theoretically possible, but the implementations are further
2168 limited due to memory layouts.
e8581e3d 2169
6807c846 2170 If unsure, say Y.
8ab3820f
KC
2171
2172# Relocation on x86 needs some additional build support
845adf72
PA
2173config X86_NEED_RELOCS
2174 def_bool y
8ab3820f 2175 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2176
506f1d07 2177config PHYSICAL_ALIGN
a0215061 2178 hex "Alignment value to which kernel should be aligned"
8ab3820f 2179 default "0x200000"
a0215061
KC
2180 range 0x2000 0x1000000 if X86_32
2181 range 0x200000 0x1000000 if X86_64
a7f7f624 2182 help
506f1d07
SR
2183 This value puts the alignment restrictions on physical address
2184 where kernel is loaded and run from. Kernel is compiled for an
2185 address which meets above alignment restriction.
2186
2187 If bootloader loads the kernel at a non-aligned address and
2188 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2189 address aligned to above value and run from there.
2190
2191 If bootloader loads the kernel at a non-aligned address and
2192 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2193 load address and decompress itself to the address it has been
2194 compiled for and run from there. The address for which kernel is
2195 compiled already meets above alignment restrictions. Hence the
2196 end result is that kernel runs from a physical address meeting
2197 above alignment restrictions.
2198
a0215061
KC
2199 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2200 this value must be a multiple of 0x200000.
2201
506f1d07
SR
2202 Don't change this unless you know what you are doing.
2203
eedb92ab
KS
2204config DYNAMIC_MEMORY_LAYOUT
2205 bool
a7f7f624 2206 help
eedb92ab
KS
2207 This option makes base addresses of vmalloc and vmemmap as well as
2208 __PAGE_OFFSET movable during boot.
2209
0483e1fa
TG
2210config RANDOMIZE_MEMORY
2211 bool "Randomize the kernel memory sections"
2212 depends on X86_64
2213 depends on RANDOMIZE_BASE
eedb92ab 2214 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2215 default RANDOMIZE_BASE
a7f7f624 2216 help
0483e1fa
TG
2217 Randomizes the base virtual address of kernel memory sections
2218 (physical memory mapping, vmalloc & vmemmap). This security feature
2219 makes exploits relying on predictable memory locations less reliable.
2220
2221 The order of allocations remains unchanged. Entropy is generated in
2222 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2223 configuration have in average 30,000 different possible virtual
2224 addresses for each memory section.
2225
6807c846 2226 If unsure, say Y.
0483e1fa 2227
90397a41
TG
2228config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2229 hex "Physical memory mapping padding" if EXPERT
2230 depends on RANDOMIZE_MEMORY
2231 default "0xa" if MEMORY_HOTPLUG
2232 default "0x0"
2233 range 0x1 0x40 if MEMORY_HOTPLUG
2234 range 0x0 0x40
a7f7f624 2235 help
90397a41
TG
2236 Define the padding in terabytes added to the existing physical
2237 memory size during kernel memory randomization. It is useful
2238 for memory hotplug support but reduces the entropy available for
2239 address randomization.
2240
2241 If unsure, leave at the default value.
2242
506f1d07 2243config HOTPLUG_CPU
bebd024e 2244 def_bool y
40b31360 2245 depends on SMP
506f1d07 2246
80aa1dff
FY
2247config BOOTPARAM_HOTPLUG_CPU0
2248 bool "Set default setting of cpu0_hotpluggable"
2c922cd0 2249 depends on HOTPLUG_CPU
a7f7f624 2250 help
80aa1dff
FY
2251 Set whether default state of cpu0_hotpluggable is on or off.
2252
2253 Say Y here to enable CPU0 hotplug by default. If this switch
2254 is turned on, there is no need to give cpu0_hotplug kernel
2255 parameter and the CPU0 hotplug feature is enabled by default.
2256
2257 Please note: there are two known CPU0 dependencies if you want
2258 to enable the CPU0 hotplug feature either by this switch or by
2259 cpu0_hotplug kernel parameter.
2260
2261 First, resume from hibernate or suspend always starts from CPU0.
2262 So hibernate and suspend are prevented if CPU0 is offline.
2263
2264 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2265 offline if any interrupt can not migrate out of CPU0. There may
2266 be other CPU0 dependencies.
2267
2268 Please make sure the dependencies are under your control before
2269 you enable this feature.
2270
2271 Say N if you don't want to enable CPU0 hotplug feature by default.
2272 You still can enable the CPU0 hotplug feature at boot by kernel
2273 parameter cpu0_hotplug.
2274
a71c8bc5
FY
2275config DEBUG_HOTPLUG_CPU0
2276 def_bool n
2277 prompt "Debug CPU0 hotplug"
2c922cd0 2278 depends on HOTPLUG_CPU
a7f7f624 2279 help
a71c8bc5
FY
2280 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2281 soon as possible and boots up userspace with CPU0 offlined. User
2282 can online CPU0 back after boot time.
2283
2284 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2285 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2286 compilation or giving cpu0_hotplug kernel parameter at boot.
2287
2288 If unsure, say N.
2289
506f1d07 2290config COMPAT_VDSO
b0b49f26
AL
2291 def_bool n
2292 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2293 depends on COMPAT_32
a7f7f624 2294 help
b0b49f26
AL
2295 Certain buggy versions of glibc will crash if they are
2296 presented with a 32-bit vDSO that is not mapped at the address
2297 indicated in its segment table.
e84446de 2298
b0b49f26
AL
2299 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2300 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2301 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2302 the only released version with the bug, but OpenSUSE 9
2303 contains a buggy "glibc 2.3.2".
506f1d07 2304
b0b49f26
AL
2305 The symptom of the bug is that everything crashes on startup, saying:
2306 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2307
2308 Saying Y here changes the default value of the vdso32 boot
2309 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2310 This works around the glibc bug but hurts performance.
2311
2312 If unsure, say N: if you are compiling your own kernel, you
2313 are unlikely to be using a buggy version of glibc.
506f1d07 2314
3dc33bd3
KC
2315choice
2316 prompt "vsyscall table for legacy applications"
2317 depends on X86_64
625b7b7f 2318 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2319 help
2320 Legacy user code that does not know how to find the vDSO expects
2321 to be able to issue three syscalls by calling fixed addresses in
2322 kernel space. Since this location is not randomized with ASLR,
2323 it can be used to assist security vulnerability exploitation.
2324
2325 This setting can be changed at boot time via the kernel command
bd49e16e 2326 line parameter vsyscall=[emulate|xonly|none].
3dc33bd3
KC
2327
2328 On a system with recent enough glibc (2.14 or newer) and no
2329 static binaries, you can say None without a performance penalty
2330 to improve security.
2331
bd49e16e 2332 If unsure, select "Emulate execution only".
3dc33bd3 2333
3dc33bd3 2334 config LEGACY_VSYSCALL_EMULATE
bd49e16e 2335 bool "Full emulation"
3dc33bd3 2336 help
bd49e16e
AL
2337 The kernel traps and emulates calls into the fixed vsyscall
2338 address mapping. This makes the mapping non-executable, but
2339 it still contains readable known contents, which could be
2340 used in certain rare security vulnerability exploits. This
2341 configuration is recommended when using legacy userspace
2342 that still uses vsyscalls along with legacy binary
2343 instrumentation tools that require code to be readable.
2344
2345 An example of this type of legacy userspace is running
2346 Pin on an old binary that still uses vsyscalls.
2347
2348 config LEGACY_VSYSCALL_XONLY
2349 bool "Emulate execution only"
2350 help
2351 The kernel traps and emulates calls into the fixed vsyscall
2352 address mapping and does not allow reads. This
2353 configuration is recommended when userspace might use the
2354 legacy vsyscall area but support for legacy binary
2355 instrumentation of legacy code is not needed. It mitigates
2356 certain uses of the vsyscall area as an ASLR-bypassing
2357 buffer.
3dc33bd3
KC
2358
2359 config LEGACY_VSYSCALL_NONE
2360 bool "None"
2361 help
2362 There will be no vsyscall mapping at all. This will
2363 eliminate any risk of ASLR bypass due to the vsyscall
2364 fixed address mapping. Attempts to use the vsyscalls
2365 will be reported to dmesg, so that either old or
2366 malicious userspace programs can be identified.
2367
2368endchoice
2369
516cbf37
TB
2370config CMDLINE_BOOL
2371 bool "Built-in kernel command line"
a7f7f624 2372 help
516cbf37
TB
2373 Allow for specifying boot arguments to the kernel at
2374 build time. On some systems (e.g. embedded ones), it is
2375 necessary or convenient to provide some or all of the
2376 kernel boot arguments with the kernel itself (that is,
2377 to not rely on the boot loader to provide them.)
2378
2379 To compile command line arguments into the kernel,
2380 set this option to 'Y', then fill in the
69711ca1 2381 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2382
2383 Systems with fully functional boot loaders (i.e. non-embedded)
2384 should leave this option set to 'N'.
2385
2386config CMDLINE
2387 string "Built-in kernel command string"
2388 depends on CMDLINE_BOOL
2389 default ""
a7f7f624 2390 help
516cbf37
TB
2391 Enter arguments here that should be compiled into the kernel
2392 image and used at boot time. If the boot loader provides a
2393 command line at boot time, it is appended to this string to
2394 form the full kernel command line, when the system boots.
2395
2396 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2397 change this behavior.
2398
2399 In most cases, the command line (whether built-in or provided
2400 by the boot loader) should specify the device for the root
2401 file system.
2402
2403config CMDLINE_OVERRIDE
2404 bool "Built-in command line overrides boot loader arguments"
645e6466 2405 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2406 help
516cbf37
TB
2407 Set this option to 'Y' to have the kernel ignore the boot loader
2408 command line, and use ONLY the built-in command line.
2409
2410 This is used to work around broken boot loaders. This should
2411 be set to 'N' under normal conditions.
2412
a5b9e5a2
AL
2413config MODIFY_LDT_SYSCALL
2414 bool "Enable the LDT (local descriptor table)" if EXPERT
2415 default y
a7f7f624 2416 help
a5b9e5a2
AL
2417 Linux can allow user programs to install a per-process x86
2418 Local Descriptor Table (LDT) using the modify_ldt(2) system
2419 call. This is required to run 16-bit or segmented code such as
2420 DOSEMU or some Wine programs. It is also used by some very old
2421 threading libraries.
2422
2423 Enabling this feature adds a small amount of overhead to
2424 context switches and increases the low-level kernel attack
2425 surface. Disabling it removes the modify_ldt(2) system call.
2426
2427 Saying 'N' here may make sense for embedded or server kernels.
2428
b700e7f0
SJ
2429source "kernel/livepatch/Kconfig"
2430
506f1d07
SR
2431endmenu
2432
3072e413
MH
2433config ARCH_HAS_ADD_PAGES
2434 def_bool y
2435 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2436
506f1d07
SR
2437config ARCH_ENABLE_MEMORY_HOTPLUG
2438 def_bool y
2439 depends on X86_64 || (X86_32 && HIGHMEM)
2440
35551053
GH
2441config ARCH_ENABLE_MEMORY_HOTREMOVE
2442 def_bool y
2443 depends on MEMORY_HOTPLUG
2444
e534c7c5 2445config USE_PERCPU_NUMA_NODE_ID
645a7919 2446 def_bool y
e534c7c5
LS
2447 depends on NUMA
2448
9491846f
KS
2449config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2450 def_bool y
2451 depends on X86_64 || X86_PAE
2452
c177c81e
NH
2453config ARCH_ENABLE_HUGEPAGE_MIGRATION
2454 def_bool y
2455 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2456
9c670ea3
NH
2457config ARCH_ENABLE_THP_MIGRATION
2458 def_bool y
2459 depends on X86_64 && TRANSPARENT_HUGEPAGE
2460
da85f865 2461menu "Power management and ACPI options"
e279b6c1
SR
2462
2463config ARCH_HIBERNATION_HEADER
3c2362e6 2464 def_bool y
44556530 2465 depends on HIBERNATION
e279b6c1
SR
2466
2467source "kernel/power/Kconfig"
2468
2469source "drivers/acpi/Kconfig"
2470
efafc8b2
FT
2471source "drivers/sfi/Kconfig"
2472
a6b68076 2473config X86_APM_BOOT
6fc108a0 2474 def_bool y
282e5aab 2475 depends on APM
a6b68076 2476
e279b6c1
SR
2477menuconfig APM
2478 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2479 depends on X86_32 && PM_SLEEP
a7f7f624 2480 help
e279b6c1
SR
2481 APM is a BIOS specification for saving power using several different
2482 techniques. This is mostly useful for battery powered laptops with
2483 APM compliant BIOSes. If you say Y here, the system time will be
2484 reset after a RESUME operation, the /proc/apm device will provide
2485 battery status information, and user-space programs will receive
2486 notification of APM "events" (e.g. battery status change).
2487
2488 If you select "Y" here, you can disable actual use of the APM
2489 BIOS by passing the "apm=off" option to the kernel at boot time.
2490
2491 Note that the APM support is almost completely disabled for
2492 machines with more than one CPU.
2493
2494 In order to use APM, you will need supporting software. For location
151f4e2b 2495 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2496 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2497 <http://www.tldp.org/docs.html#howto>.
2498
2499 This driver does not spin down disk drives (see the hdparm(8)
2500 manpage ("man 8 hdparm") for that), and it doesn't turn off
2501 VESA-compliant "green" monitors.
2502
2503 This driver does not support the TI 4000M TravelMate and the ACER
2504 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2505 desktop machines also don't have compliant BIOSes, and this driver
2506 may cause those machines to panic during the boot phase.
2507
2508 Generally, if you don't have a battery in your machine, there isn't
2509 much point in using this driver and you should say N. If you get
2510 random kernel OOPSes or reboots that don't seem to be related to
2511 anything, try disabling/enabling this option (or disabling/enabling
2512 APM in your BIOS).
2513
2514 Some other things you should try when experiencing seemingly random,
2515 "weird" problems:
2516
2517 1) make sure that you have enough swap space and that it is
2518 enabled.
2519 2) pass the "no-hlt" option to the kernel
2520 3) switch on floating point emulation in the kernel and pass
2521 the "no387" option to the kernel
2522 4) pass the "floppy=nodma" option to the kernel
2523 5) pass the "mem=4M" option to the kernel (thereby disabling
2524 all but the first 4 MB of RAM)
2525 6) make sure that the CPU is not over clocked.
2526 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2527 8) disable the cache from your BIOS settings
2528 9) install a fan for the video card or exchange video RAM
2529 10) install a better fan for the CPU
2530 11) exchange RAM chips
2531 12) exchange the motherboard.
2532
2533 To compile this driver as a module, choose M here: the
2534 module will be called apm.
2535
2536if APM
2537
2538config APM_IGNORE_USER_SUSPEND
2539 bool "Ignore USER SUSPEND"
a7f7f624 2540 help
e279b6c1
SR
2541 This option will ignore USER SUSPEND requests. On machines with a
2542 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2543 series notebooks, it is necessary to say Y because of a BIOS bug.
2544
2545config APM_DO_ENABLE
2546 bool "Enable PM at boot time"
a7f7f624 2547 help
e279b6c1
SR
2548 Enable APM features at boot time. From page 36 of the APM BIOS
2549 specification: "When disabled, the APM BIOS does not automatically
2550 power manage devices, enter the Standby State, enter the Suspend
2551 State, or take power saving steps in response to CPU Idle calls."
2552 This driver will make CPU Idle calls when Linux is idle (unless this
2553 feature is turned off -- see "Do CPU IDLE calls", below). This
2554 should always save battery power, but more complicated APM features
2555 will be dependent on your BIOS implementation. You may need to turn
2556 this option off if your computer hangs at boot time when using APM
2557 support, or if it beeps continuously instead of suspending. Turn
2558 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2559 T400CDT. This is off by default since most machines do fine without
2560 this feature.
2561
2562config APM_CPU_IDLE
dd8af076 2563 depends on CPU_IDLE
e279b6c1 2564 bool "Make CPU Idle calls when idle"
a7f7f624 2565 help
e279b6c1
SR
2566 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2567 On some machines, this can activate improved power savings, such as
2568 a slowed CPU clock rate, when the machine is idle. These idle calls
2569 are made after the idle loop has run for some length of time (e.g.,
2570 333 mS). On some machines, this will cause a hang at boot time or
2571 whenever the CPU becomes idle. (On machines with more than one CPU,
2572 this option does nothing.)
2573
2574config APM_DISPLAY_BLANK
2575 bool "Enable console blanking using APM"
a7f7f624 2576 help
e279b6c1
SR
2577 Enable console blanking using the APM. Some laptops can use this to
2578 turn off the LCD backlight when the screen blanker of the Linux
2579 virtual console blanks the screen. Note that this is only used by
2580 the virtual console screen blanker, and won't turn off the backlight
2581 when using the X Window system. This also doesn't have anything to
2582 do with your VESA-compliant power-saving monitor. Further, this
2583 option doesn't work for all laptops -- it might not turn off your
2584 backlight at all, or it might print a lot of errors to the console,
2585 especially if you are using gpm.
2586
2587config APM_ALLOW_INTS
2588 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2589 help
e279b6c1
SR
2590 Normally we disable external interrupts while we are making calls to
2591 the APM BIOS as a measure to lessen the effects of a badly behaving
2592 BIOS implementation. The BIOS should reenable interrupts if it
2593 needs to. Unfortunately, some BIOSes do not -- especially those in
2594 many of the newer IBM Thinkpads. If you experience hangs when you
2595 suspend, try setting this to Y. Otherwise, say N.
2596
e279b6c1
SR
2597endif # APM
2598
bb0a56ec 2599source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2600
2601source "drivers/cpuidle/Kconfig"
2602
27471fdb
AH
2603source "drivers/idle/Kconfig"
2604
e279b6c1
SR
2605endmenu
2606
2607
2608menu "Bus options (PCI etc.)"
2609
e279b6c1
SR
2610choice
2611 prompt "PCI access mode"
efefa6f6 2612 depends on X86_32 && PCI
e279b6c1 2613 default PCI_GOANY
a7f7f624 2614 help
e279b6c1
SR
2615 On PCI systems, the BIOS can be used to detect the PCI devices and
2616 determine their configuration. However, some old PCI motherboards
2617 have BIOS bugs and may crash if this is done. Also, some embedded
2618 PCI-based systems don't have any BIOS at all. Linux can also try to
2619 detect the PCI hardware directly without using the BIOS.
2620
2621 With this option, you can specify how Linux should detect the
2622 PCI devices. If you choose "BIOS", the BIOS will be used,
2623 if you choose "Direct", the BIOS won't be used, and if you
2624 choose "MMConfig", then PCI Express MMCONFIG will be used.
2625 If you choose "Any", the kernel will try MMCONFIG, then the
2626 direct access method and falls back to the BIOS if that doesn't
2627 work. If unsure, go with the default, which is "Any".
2628
2629config PCI_GOBIOS
2630 bool "BIOS"
2631
2632config PCI_GOMMCONFIG
2633 bool "MMConfig"
2634
2635config PCI_GODIRECT
2636 bool "Direct"
2637
3ef0e1f8 2638config PCI_GOOLPC
76fb6570 2639 bool "OLPC XO-1"
3ef0e1f8
AS
2640 depends on OLPC
2641
2bdd1b03
AS
2642config PCI_GOANY
2643 bool "Any"
2644
e279b6c1
SR
2645endchoice
2646
2647config PCI_BIOS
3c2362e6 2648 def_bool y
efefa6f6 2649 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2650
2651# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2652config PCI_DIRECT
3c2362e6 2653 def_bool y
0aba496f 2654 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2655
2656config PCI_MMCONFIG
b45c9f36
JK
2657 bool "Support mmconfig PCI config space access" if X86_64
2658 default y
8364e1f8 2659 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
b45c9f36 2660 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2661
3ef0e1f8 2662config PCI_OLPC
2bdd1b03
AS
2663 def_bool y
2664 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2665
b5401a96
AN
2666config PCI_XEN
2667 def_bool y
2668 depends on PCI && XEN
2669 select SWIOTLB_XEN
2670
8364e1f8
JK
2671config MMCONF_FAM10H
2672 def_bool y
2673 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2674
3f6ea84a 2675config PCI_CNB20LE_QUIRK
6a108a14 2676 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2677 depends on PCI
3f6ea84a
IS
2678 help
2679 Read the PCI windows out of the CNB20LE host bridge. This allows
2680 PCI hotplug to work on systems with the CNB20LE chipset which do
2681 not have ACPI.
2682
64a5fed6
BH
2683 There's no public spec for this chipset, and this functionality
2684 is known to be incomplete.
2685
2686 You should say N unless you know you need this.
2687
3a495511 2688config ISA_BUS
17a2a129 2689 bool "ISA bus support on modern systems" if EXPERT
3a495511 2690 help
17a2a129
WBG
2691 Expose ISA bus device drivers and options available for selection and
2692 configuration. Enable this option if your target machine has an ISA
2693 bus. ISA is an older system, displaced by PCI and newer bus
2694 architectures -- if your target machine is modern, it probably does
2695 not have an ISA bus.
3a495511
WBG
2696
2697 If unsure, say N.
2698
1c00f016 2699# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2700config ISA_DMA_API
1c00f016
DR
2701 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2702 default y
2703 help
2704 Enables ISA-style DMA support for devices requiring such controllers.
2705 If unsure, say Y.
e279b6c1 2706
51e68d05
LT
2707if X86_32
2708
e279b6c1
SR
2709config ISA
2710 bool "ISA support"
a7f7f624 2711 help
e279b6c1
SR
2712 Find out whether you have ISA slots on your motherboard. ISA is the
2713 name of a bus system, i.e. the way the CPU talks to the other stuff
2714 inside your box. Other bus systems are PCI, EISA, MicroChannel
2715 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2716 newer boards don't support it. If you have ISA, say Y, otherwise N.
2717
e279b6c1
SR
2718config SCx200
2719 tristate "NatSemi SCx200 support"
a7f7f624 2720 help
e279b6c1
SR
2721 This provides basic support for National Semiconductor's
2722 (now AMD's) Geode processors. The driver probes for the
2723 PCI-IDs of several on-chip devices, so its a good dependency
2724 for other scx200_* drivers.
2725
2726 If compiled as a module, the driver is named scx200.
2727
2728config SCx200HR_TIMER
2729 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2730 depends on SCx200
e279b6c1 2731 default y
a7f7f624 2732 help
e279b6c1
SR
2733 This driver provides a clocksource built upon the on-chip
2734 27MHz high-resolution timer. Its also a workaround for
2735 NSC Geode SC-1100's buggy TSC, which loses time when the
2736 processor goes idle (as is done by the scheduler). The
2737 other workaround is idle=poll boot option.
2738
3ef0e1f8
AS
2739config OLPC
2740 bool "One Laptop Per Child support"
54008979 2741 depends on !X86_PAE
3c554946 2742 select GPIOLIB
dc3119e7 2743 select OF
45bb1674 2744 select OF_PROMTREE
b4e51854 2745 select IRQ_DOMAIN
0c3d931b 2746 select OLPC_EC
a7f7f624 2747 help
3ef0e1f8
AS
2748 Add support for detecting the unique features of the OLPC
2749 XO hardware.
2750
a3128588
DD
2751config OLPC_XO1_PM
2752 bool "OLPC XO-1 Power Management"
fa112cf1 2753 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 2754 help
97c4cb71 2755 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2756
cfee9597
DD
2757config OLPC_XO1_RTC
2758 bool "OLPC XO-1 Real Time Clock"
2759 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 2760 help
cfee9597
DD
2761 Add support for the XO-1 real time clock, which can be used as a
2762 programmable wakeup source.
2763
7feda8e9
DD
2764config OLPC_XO1_SCI
2765 bool "OLPC XO-1 SCI extras"
92e830f2 2766 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2767 depends on INPUT=y
d8d01a63 2768 select POWER_SUPPLY
a7f7f624 2769 help
7feda8e9 2770 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2771 - EC-driven system wakeups
7feda8e9 2772 - Power button
7bc74b3d 2773 - Ebook switch
2cf2baea 2774 - Lid switch
e1040ac6
DD
2775 - AC adapter status updates
2776 - Battery status updates
7feda8e9 2777
a0f30f59
DD
2778config OLPC_XO15_SCI
2779 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2780 depends on OLPC && ACPI
2781 select POWER_SUPPLY
a7f7f624 2782 help
a0f30f59
DD
2783 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2784 - EC-driven system wakeups
2785 - AC adapter status updates
2786 - Battery status updates
bf1ebf00 2787
d4f3e350
EW
2788config ALIX
2789 bool "PCEngines ALIX System Support (LED setup)"
2790 select GPIOLIB
a7f7f624 2791 help
d4f3e350
EW
2792 This option enables system support for the PCEngines ALIX.
2793 At present this just sets up LEDs for GPIO control on
2794 ALIX2/3/6 boards. However, other system specific setup should
2795 get added here.
2796
2797 Note: You must still enable the drivers for GPIO and LED support
2798 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2799
2800 Note: You have to set alix.force=1 for boards with Award BIOS.
2801
da4e3302
PP
2802config NET5501
2803 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2804 select GPIOLIB
a7f7f624 2805 help
da4e3302
PP
2806 This option enables system support for the Soekris Engineering net5501.
2807
3197059a
PP
2808config GEOS
2809 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2810 select GPIOLIB
2811 depends on DMI
a7f7f624 2812 help
3197059a
PP
2813 This option enables system support for the Traverse Technologies GEOS.
2814
7d029125
VD
2815config TS5500
2816 bool "Technologic Systems TS-5500 platform support"
2817 depends on MELAN
2818 select CHECK_SIGNATURE
2819 select NEW_LEDS
2820 select LEDS_CLASS
a7f7f624 2821 help
7d029125
VD
2822 This option enables system support for the Technologic Systems TS-5500.
2823
bc0120fd
SR
2824endif # X86_32
2825
23ac4ae8 2826config AMD_NB
e279b6c1 2827 def_bool y
0e152cd7 2828 depends on CPU_SUP_AMD && PCI
e279b6c1 2829
e3263ab3
DR
2830config X86_SYSFB
2831 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2832 help
2833 Firmwares often provide initial graphics framebuffers so the BIOS,
2834 bootloader or kernel can show basic video-output during boot for
2835 user-guidance and debugging. Historically, x86 used the VESA BIOS
2836 Extensions and EFI-framebuffers for this, which are mostly limited
2837 to x86.
2838 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2839 framebuffers so the new generic system-framebuffer drivers can be
2840 used on x86. If the framebuffer is not compatible with the generic
e3a5dc08 2841 modes, it is advertised as fallback platform framebuffer so legacy
e3263ab3
DR
2842 drivers like efifb, vesafb and uvesafb can pick it up.
2843 If this option is not selected, all system framebuffers are always
2844 marked as fallback platform framebuffers as usual.
2845
2846 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2847 not be able to pick up generic system framebuffers if this option
2848 is selected. You are highly encouraged to enable simplefb as
2849 replacement if you select this option. simplefb can correctly deal
2850 with generic system framebuffers. But you should still keep vesafb
2851 and others enabled as fallback if a system framebuffer is
2852 incompatible with simplefb.
2853
2854 If unsure, say Y.
2855
e279b6c1
SR
2856endmenu
2857
2858
1572497c 2859menu "Binary Emulations"
e279b6c1
SR
2860
2861config IA32_EMULATION
2862 bool "IA32 Emulation"
2863 depends on X86_64
39f88911 2864 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2865 select BINFMT_ELF
a97f52e6 2866 select COMPAT_BINFMT_ELF
39f88911 2867 select COMPAT_OLD_SIGACTION
a7f7f624 2868 help
5fd92e65
L
2869 Include code to run legacy 32-bit programs under a
2870 64-bit kernel. You should likely turn this on, unless you're
2871 100% sure that you don't have any 32-bit programs left.
e279b6c1
SR
2872
2873config IA32_AOUT
8f9ca475
IM
2874 tristate "IA32 a.out support"
2875 depends on IA32_EMULATION
eac61655 2876 depends on BROKEN
a7f7f624 2877 help
8f9ca475 2878 Support old a.out binaries in the 32bit emulation.
e279b6c1 2879
0bf62763 2880config X86_X32
6ea30386 2881 bool "x32 ABI for 64-bit mode"
9b54050b 2882 depends on X86_64
a7f7f624 2883 help
5fd92e65
L
2884 Include code to run binaries for the x32 native 32-bit ABI
2885 for 64-bit processors. An x32 process gets access to the
2886 full 64-bit register file and wide data path while leaving
2887 pointers at 32 bits for smaller memory footprint.
2888
2889 You will need a recent binutils (2.22 or later) with
2890 elf32_x86_64 support enabled to compile a kernel with this
2891 option set.
2892
953fee1d
IM
2893config COMPAT_32
2894 def_bool y
2895 depends on IA32_EMULATION || X86_32
2896 select HAVE_UID16
2897 select OLD_SIGSUSPEND3
2898
e279b6c1 2899config COMPAT
3c2362e6 2900 def_bool y
0bf62763 2901 depends on IA32_EMULATION || X86_X32
e279b6c1 2902
3120e25e 2903if COMPAT
e279b6c1 2904config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2905 def_bool y
e279b6c1
SR
2906
2907config SYSVIPC_COMPAT
3c2362e6 2908 def_bool y
3120e25e 2909 depends on SYSVIPC
3120e25e 2910endif
ee009e4a 2911
e279b6c1
SR
2912endmenu
2913
2914
e5beae16
KP
2915config HAVE_ATOMIC_IOMAP
2916 def_bool y
2917 depends on X86_32
2918
e279b6c1
SR
2919source "drivers/firmware/Kconfig"
2920
edf88417 2921source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
2922
2923source "arch/x86/Kconfig.assembler"