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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
117ed454 17 select HAVE_DEBUG_STACKOVERFLOW
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IM
18 select MODULES_USE_ELF_REL
19 select OLD_SIGACTION
7ac87074 20 select GENERIC_VDSO_32
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SR
21
22config X86_64
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JB
23 def_bool y
24 depends on 64BIT
d94e0685 25 # Options that are inherently 64-bit kernel only:
4eb0716e 26 select ARCH_HAS_GIGANTIC_PAGE
c12d3362 27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
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IM
28 select ARCH_USE_CMPXCHG_LOCKREF
29 select HAVE_ARCH_SOFT_DIRTY
30 select MODULES_USE_ELF_RELA
f616ab59 31 select NEED_DMA_MAP_STATE
09230cbc 32 select SWIOTLB
1032c0ba 33
518049d9
SRV
34config FORCE_DYNAMIC_FTRACE
35 def_bool y
36 depends on X86_32
37 depends on FUNCTION_TRACER
38 select DYNAMIC_FTRACE
39 help
40 We keep the static function tracing (!DYNAMIC_FTRACE) around
41 in order to test the non static function tracing in the
42 generic code, as other architectures still use it. But we
43 only need to keep it around for x86_64. No need to keep it
44 for x86_32. For x86_32, force DYNAMIC_FTRACE.
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IM
45#
46# Arch settings
47#
48# ( Note that options that are marked 'if X86_64' could in principle be
49# ported to 32-bit as well. )
50#
8d5fffb9 51config X86
3c2362e6 52 def_bool y
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IM
53 #
54 # Note: keep this list sorted alphabetically
55 #
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IM
56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
942fa985 58 select ARCH_32BIT_OFF_T if X86_32
2a21ad57 59 select ARCH_CLOCKSOURCE_INIT
c763ea26 60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
fa5b6ec9 61 select ARCH_HAS_DEBUG_VIRTUAL
399145f9 62 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
21266be9 63 select ARCH_HAS_DEVMEM_IS_ALLOWED
b1a57bbf 64 select ARCH_HAS_EARLY_DEBUG if KGDB
6471b825 65 select ARCH_HAS_ELF_RANDOMIZE
72d93104 66 select ARCH_HAS_FAST_MULTIPLIER
316d097c 67 select ARCH_HAS_FILTER_PGPROT
6974f0c4 68 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 69 select ARCH_HAS_GCOV_PROFILE_ALL
0f1441b4 70 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
0c9c1d56 71 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE
0ebeea8c 73 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
c763ea26 74 select ARCH_HAS_PMEM_API if X86_64
17596731 75 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 76 select ARCH_HAS_PTE_SPECIAL
0aed55af 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
ec6347bb 78 select ARCH_HAS_COPY_MC if X86_64
d2852a22 79 select ARCH_HAS_SET_MEMORY
d253ca0c 80 select ARCH_HAS_SET_DIRECT_MAP
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LA
81 select ARCH_HAS_STRICT_KERNEL_RWX
82 select ARCH_HAS_STRICT_MODULE_RWX
ac1ab12a 83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
25c619e5 84 select ARCH_HAS_SYSCALL_WRAPPER
c6d30853 85 select ARCH_HAS_UBSAN_SANITIZE_ALL
7e01ccb4 86 select ARCH_HAS_DEBUG_WX
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IM
87 select ARCH_HAVE_NMI_SAFE_CMPXCHG
88 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 89 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 90 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 91 select ARCH_STACKWALK
2c870e61 92 select ARCH_SUPPORTS_ACPI
6471b825 93 select ARCH_SUPPORTS_ATOMIC_RMW
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IM
94 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
95 select ARCH_USE_BUILTIN_BSWAP
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IM
96 select ARCH_USE_QUEUED_RWLOCKS
97 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 98 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 99 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 100 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 101 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
3876d4a3 102 select ARCH_WANT_HUGE_PMD_SHARE
38d8b4e6 103 select ARCH_WANTS_THP_SWAP if X86_64
10916706 104 select BUILDTIME_TABLE_SORT
6471b825 105 select CLKEVT_I8253
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IM
106 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
107 select CLOCKSOURCE_WATCHDOG
6471b825 108 select DCACHE_WORD_ACCESS
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LT
109 select EDAC_ATOMIC_SCRUB
110 select EDAC_SUPPORT
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111 select GENERIC_CLOCKEVENTS
112 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
113 select GENERIC_CLOCKEVENTS_MIN_ADJUST
114 select GENERIC_CMOS_UPDATE
115 select GENERIC_CPU_AUTOPROBE
61dc0f55 116 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 117 select GENERIC_EARLY_IOREMAP
27d6b4d1 118 select GENERIC_ENTRY
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IM
119 select GENERIC_FIND_FIRST_BIT
120 select GENERIC_IOMAP
c7d6c9dd 121 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 122 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 123 select GENERIC_IRQ_MIGRATION if SMP
6471b825 124 select GENERIC_IRQ_PROBE
c201c917 125 select GENERIC_IRQ_RESERVATION_MODE
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IM
126 select GENERIC_IRQ_SHOW
127 select GENERIC_PENDING_IRQ if SMP
2ae27137 128 select GENERIC_PTDUMP
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129 select GENERIC_SMP_IDLE_THREAD
130 select GENERIC_STRNCPY_FROM_USER
131 select GENERIC_STRNLEN_USER
132 select GENERIC_TIME_VSYSCALL
7ac87074 133 select GENERIC_GETTIMEOFDAY
550a77a7 134 select GENERIC_VDSO_TIME_NS
39656e83 135 select GUP_GET_PTE_LOW_HIGH if X86_PAE
17e5888e 136 select HARDIRQS_SW_RESEND
7edaeb68 137 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
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138 select HAVE_ACPI_APEI if ACPI
139 select HAVE_ACPI_APEI_NMI if ACPI
140 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
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141 select HAVE_ARCH_AUDITSYSCALL
142 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
143 select HAVE_ARCH_JUMP_LABEL
b34006c4 144 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 145 select HAVE_ARCH_KASAN if X86_64
0609ae01 146 select HAVE_ARCH_KASAN_VMALLOC if X86_64
6471b825 147 select HAVE_ARCH_KGDB
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DC
148 select HAVE_ARCH_MMAP_RND_BITS if MMU
149 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 150 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 151 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 152 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 153 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 154 select HAVE_ARCH_STACKLEAK
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155 select HAVE_ARCH_TRACEHOOK
156 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 157 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 158 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
e37e43a4 159 select HAVE_ARCH_VMAP_STACK if X86_64
c763ea26 160 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 161 select HAVE_ASM_MODVERSIONS
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162 select HAVE_CMPXCHG_DOUBLE
163 select HAVE_CMPXCHG_LOCAL
164 select HAVE_CONTEXT_TRACKING if X86_64
cf4db259 165 select HAVE_C_RECORDMCOUNT
6471b825 166 select HAVE_DEBUG_KMEMLEAK
6471b825 167 select HAVE_DMA_CONTIGUOUS
677aa9f7 168 select HAVE_DYNAMIC_FTRACE
06aeaaea 169 select HAVE_DYNAMIC_FTRACE_WITH_REGS
562955fe 170 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
03f5781b 171 select HAVE_EBPF_JIT
58340a07 172 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 173 select HAVE_EISA
5f56a5df 174 select HAVE_EXIT_THREAD
67a929e0 175 select HAVE_FAST_GUP
644e0e8d 176 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 177 select HAVE_FTRACE_MCOUNT_RECORD
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178 select HAVE_FUNCTION_GRAPH_TRACER
179 select HAVE_FUNCTION_TRACER
6b90bd4b 180 select HAVE_GCC_PLUGINS
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181 select HAVE_HW_BREAKPOINT
182 select HAVE_IDE
183 select HAVE_IOREMAP_PROT
6471b825 184 select HAVE_IRQ_TIME_ACCOUNTING
2e9f3bdd 185 select HAVE_KERNEL_BZIP2
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IM
186 select HAVE_KERNEL_GZIP
187 select HAVE_KERNEL_LZ4
2e9f3bdd 188 select HAVE_KERNEL_LZMA
13510997 189 select HAVE_KERNEL_LZO
6471b825 190 select HAVE_KERNEL_XZ
fb46d057 191 select HAVE_KERNEL_ZSTD
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192 select HAVE_KPROBES
193 select HAVE_KPROBES_ON_FTRACE
540adea3 194 select HAVE_FUNCTION_ERROR_INJECTION
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195 select HAVE_KRETPROBES
196 select HAVE_KVM
197 select HAVE_LIVEPATCH if X86_64
0102752e 198 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 199 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 200 select HAVE_MOVE_PMD
42a0bb3f 201 select HAVE_NMI
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202 select HAVE_OPROFILE
203 select HAVE_OPTPROBES
204 select HAVE_PCSPKR_PLATFORM
205 select HAVE_PERF_EVENTS
c01d4323 206 select HAVE_PERF_EVENTS_NMI
92e5aae4 207 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 208 select HAVE_PCI
c5e63197 209 select HAVE_PERF_REGS
c5ebcedb 210 select HAVE_PERF_USER_STACK_DUMP
ff2e6d72 211 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
00998085 212 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 213 select HAVE_REGS_AND_STACK_ACCESS_API
6415b38b 214 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
3c88ee19 215 select HAVE_FUNCTION_ARG_ACCESS_API
d148eac0 216 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
c763ea26 217 select HAVE_STACK_VALIDATION if X86_64
e6d6c071 218 select HAVE_STATIC_CALL
1e7e4788 219 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
d6761b8f 220 select HAVE_RSEQ
6471b825 221 select HAVE_SYSCALL_TRACEPOINTS
6471b825 222 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 223 select HAVE_USER_RETURN_NOTIFIER
7ac87074 224 select HAVE_GENERIC_VDSO
05736e4a 225 select HOTPLUG_SMT if SMP
c0185808 226 select IRQ_FORCED_THREADING
86596f0a 227 select NEED_SG_DMA_LENGTH
2eac9c2d 228 select PCI_DOMAINS if PCI
625210cf 229 select PCI_LOCKLESS_CONFIG if PCI
6471b825 230 select PERF_EVENTS
3195ef59 231 select RTC_LIB
d6faca40 232 select RTC_MC146818_LIB
6471b825 233 select SPARSE_IRQ
83fe27ea 234 select SRCU
1e7e4788 235 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
6471b825 236 select SYSCTL_EXCEPTION_TRACE
15f4eae7 237 select THREAD_INFO_IN_TASK
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IM
238 select USER_STACKTRACE_SUPPORT
239 select VIRT_TO_BUS
3b02a051 240 select HAVE_ARCH_KCSAN if X86_64
6471b825 241 select X86_FEATURE_NAMES if PROC_FS
0c608dad 242 select PROC_PID_ARCH_STATUS if PROC_FS
9e2b4be3 243 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
7d8330a5 244
ba7e4d13 245config INSTRUCTION_DECODER
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JB
246 def_bool y
247 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 248
51b26ada
LT
249config OUTPUT_FORMAT
250 string
251 default "elf32-i386" if X86_32
252 default "elf64-x86-64" if X86_64
253
8d5fffb9 254config LOCKDEP_SUPPORT
3c2362e6 255 def_bool y
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SR
256
257config STACKTRACE_SUPPORT
3c2362e6 258 def_bool y
8d5fffb9 259
8d5fffb9 260config MMU
3c2362e6 261 def_bool y
8d5fffb9 262
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DC
263config ARCH_MMAP_RND_BITS_MIN
264 default 28 if 64BIT
265 default 8
266
267config ARCH_MMAP_RND_BITS_MAX
268 default 32 if 64BIT
269 default 16
270
271config ARCH_MMAP_RND_COMPAT_BITS_MIN
272 default 8
273
274config ARCH_MMAP_RND_COMPAT_BITS_MAX
275 default 16
276
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SR
277config SBUS
278 bool
279
280config GENERIC_ISA_DMA
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JB
281 def_bool y
282 depends on ISA_DMA_API
8d5fffb9 283
8d5fffb9 284config GENERIC_BUG
3c2362e6 285 def_bool y
8d5fffb9 286 depends on BUG
b93a531e
JB
287 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
288
289config GENERIC_BUG_RELATIVE_POINTERS
290 bool
8d5fffb9 291
8d5fffb9 292config ARCH_MAY_HAVE_PC_FDC
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JB
293 def_bool y
294 depends on ISA_DMA_API
8d5fffb9 295
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SR
296config GENERIC_CALIBRATE_DELAY
297 def_bool y
298
9a0b8415 299config ARCH_HAS_CPU_RELAX
300 def_bool y
301
1b27d05b
PE
302config ARCH_HAS_CACHE_LINE_SIZE
303 def_bool y
304
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DH
305config ARCH_HAS_FILTER_PGPROT
306 def_bool y
307
dd5af90a 308config HAVE_SETUP_PER_CPU_AREA
89c9c4c5 309 def_bool y
b32ef636 310
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TH
311config NEED_PER_CPU_EMBED_FIRST_CHUNK
312 def_bool y
313
314config NEED_PER_CPU_PAGE_FIRST_CHUNK
11124411
TH
315 def_bool y
316
801e4062
JB
317config ARCH_HIBERNATION_POSSIBLE
318 def_bool y
801e4062 319
f4cb5700
JB
320config ARCH_SUSPEND_POSSIBLE
321 def_bool y
f4cb5700 322
53313b2c
SC
323config ARCH_WANT_GENERAL_HUGETLB
324 def_bool y
325
8d5fffb9 326config ZONE_DMA32
e0fd24a3 327 def_bool y if X86_64
8d5fffb9 328
8d5fffb9 329config AUDIT_ARCH
e0fd24a3 330 def_bool y if X86_64
8d5fffb9 331
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AM
332config ARCH_SUPPORTS_DEBUG_PAGEALLOC
333 def_bool y
334
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AR
335config KASAN_SHADOW_OFFSET
336 hex
337 depends on KASAN
338 default 0xdffffc0000000000
339
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SW
340config HAVE_INTEL_TXT
341 def_bool y
6ea30386 342 depends on INTEL_IOMMU && ACPI
69575d38 343
6b0c3d44
SR
344config X86_32_SMP
345 def_bool y
346 depends on X86_32 && SMP
347
348config X86_64_SMP
349 def_bool y
350 depends on X86_64 && SMP
351
ccbeed3a
TH
352config X86_32_LAZY_GS
353 def_bool y
8458f8c2 354 depends on X86_32 && !STACKPROTECTOR
ccbeed3a 355
2b144498
SD
356config ARCH_SUPPORTS_UPROBES
357 def_bool y
358
d20642f0
RH
359config FIX_EARLYCON_MEM
360 def_bool y
361
94d49eb3
KS
362config DYNAMIC_PHYSICAL_MASK
363 bool
364
98233368
KS
365config PGTABLE_LEVELS
366 int
77ef56e4 367 default 5 if X86_5LEVEL
98233368
KS
368 default 4 if X86_64
369 default 3 if X86_PAE
370 default 2
371
2a61f474
MY
372config CC_HAS_SANE_STACKPROTECTOR
373 bool
374 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
375 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
376 help
377 We have to make sure stack protector is unconditionally disabled if
378 the compiler produces broken code.
379
506f1d07
SR
380menu "Processor type and features"
381
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RD
382config ZONE_DMA
383 bool "DMA memory allocation support" if EXPERT
384 default y
385 help
386 DMA memory allocation support allows devices with less than 32-bit
387 addressing to allocate within the first 16MB of address space.
388 Disable if no such devices will be used.
389
390 If unsure, say Y.
391
506f1d07
SR
392config SMP
393 bool "Symmetric multi-processing support"
a7f7f624 394 help
506f1d07 395 This enables support for systems with more than one CPU. If you have
4a474157
RG
396 a system with only one CPU, say N. If you have a system with more
397 than one CPU, say Y.
506f1d07 398
4a474157 399 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
400 machines, but will use only one CPU of a multiprocessor machine. If
401 you say Y here, the kernel will run on many, but not all,
4a474157 402 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
403 will run faster if you say N here.
404
405 Note that if you say Y here and choose architecture "586" or
406 "Pentium" under "Processor family", the kernel will not work on 486
407 architectures. Similarly, multiprocessor kernels for the "PPro"
408 architecture may not work on all Pentium based boards.
409
410 People using multiprocessor machines who say Y here should also say
411 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
412 Management" code will be disabled if you say Y here.
413
cb1aaebe 414 See also <file:Documentation/x86/i386/IO-APIC.rst>,
4f4cfa6c 415 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
416 <http://www.tldp.org/docs.html#howto>.
417
418 If you don't know what to do here, say N.
419
9def39be
JT
420config X86_FEATURE_NAMES
421 bool "Processor feature human-readable names" if EMBEDDED
422 default y
a7f7f624 423 help
9def39be
JT
424 This option compiles in a table of x86 feature bits and corresponding
425 names. This is required to support /proc/cpuinfo and a few kernel
426 messages. You can disable this to save space, at the expense of
427 making those few kernel messages show numeric feature bits instead.
428
429 If in doubt, say Y.
430
06cd9a7d
YL
431config X86_X2APIC
432 bool "Support x2apic"
19e3d60d 433 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 434 help
06cd9a7d
YL
435 This enables x2apic support on CPUs that have this feature.
436
437 This allows 32-bit apic IDs (so it can support very large systems),
438 and accesses the local apic via MSRs not via mmio.
439
06cd9a7d
YL
440 If you don't know what to do here, say N.
441
6695c85b 442config X86_MPPARSE
6e87f9b7 443 bool "Enable MPS table" if ACPI || SFI
7a527688 444 default y
5ab74722 445 depends on X86_LOCAL_APIC
a7f7f624 446 help
6695c85b
YL
447 For old smp systems that do not have proper acpi support. Newer systems
448 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 449
ddd70cf9 450config GOLDFISH
b03b016f
KK
451 def_bool y
452 depends on X86_GOLDFISH
ddd70cf9 453
76b04384
DW
454config RETPOLINE
455 bool "Avoid speculative indirect branches in kernel"
456 default y
457 help
458 Compile kernel with the retpoline compiler options to guard against
459 kernel-to-user data leaks by avoiding speculative indirect
460 branches. Requires a compiler with -mindirect-branch=thunk-extern
461 support for full protection. The kernel may run slower.
462
e6d42931
JW
463config X86_CPU_RESCTRL
464 bool "x86 CPU resource control support"
6fe07ce3 465 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 466 select KERNFS
e79f15a4 467 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 468 help
e6d42931 469 Enable x86 CPU resource control support.
6fe07ce3
BM
470
471 Provide support for the allocation and monitoring of system resources
472 usage by the CPU.
473
474 Intel calls this Intel Resource Director Technology
475 (Intel(R) RDT). More information about RDT can be found in the
476 Intel x86 Architecture Software Developer Manual.
477
478 AMD calls this AMD Platform Quality of Service (AMD QoS).
479 More information about AMD QoS can be found in the AMD64 Technology
480 Platform Quality of Service Extensions manual.
78e99b4a
FY
481
482 Say N if unsure.
483
8425091f 484if X86_32
a0d0bb4d
RD
485config X86_BIGSMP
486 bool "Support for big SMP systems with more than 8 CPUs"
487 depends on SMP
a7f7f624 488 help
e133f6ea 489 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 490
c5c606d9
RT
491config X86_EXTENDED_PLATFORM
492 bool "Support for extended (non-PC) x86 platforms"
493 default y
a7f7f624 494 help
06ac8346
IM
495 If you disable this option then the kernel will only support
496 standard PC platforms. (which covers the vast majority of
497 systems out there.)
498
8425091f
RT
499 If you enable this option then you'll be able to select support
500 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 501 Goldfish (Android emulator)
8425091f 502 AMD Elan
8425091f
RT
503 RDC R-321x SoC
504 SGI 320/540 (Visual Workstation)
83125a3a 505 STA2X11-based (e.g. Northville)
3f4110a4 506 Moorestown MID devices
06ac8346
IM
507
508 If you have one of these systems, or if you want to build a
509 generic distribution kernel, say Y here - otherwise say N.
8425091f 510endif
06ac8346 511
8425091f
RT
512if X86_64
513config X86_EXTENDED_PLATFORM
514 bool "Support for extended (non-PC) x86 platforms"
515 default y
a7f7f624 516 help
8425091f
RT
517 If you disable this option then the kernel will only support
518 standard PC platforms. (which covers the vast majority of
519 systems out there.)
520
521 If you enable this option then you'll be able to select support
522 for the following (non-PC) 64 bit x86 platforms:
44b111b5 523 Numascale NumaChip
8425091f
RT
524 ScaleMP vSMP
525 SGI Ultraviolet
526
527 If you have one of these systems, or if you want to build a
528 generic distribution kernel, say Y here - otherwise say N.
529endif
c5c606d9
RT
530# This is an alphabetically sorted list of 64 bit extended platforms
531# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
532config X86_NUMACHIP
533 bool "Numascale NumaChip"
534 depends on X86_64
535 depends on X86_EXTENDED_PLATFORM
536 depends on NUMA
537 depends on SMP
538 depends on X86_X2APIC
f9726bfd 539 depends on PCI_MMCONFIG
a7f7f624 540 help
44b111b5
SP
541 Adds support for Numascale NumaChip large-SMP systems. Needed to
542 enable more than ~168 cores.
543 If you don't have one of these, you should say N here.
506f1d07 544
c5c606d9
RT
545config X86_VSMP
546 bool "ScaleMP vSMP"
6276a074 547 select HYPERVISOR_GUEST
c5c606d9
RT
548 select PARAVIRT
549 depends on X86_64 && PCI
550 depends on X86_EXTENDED_PLATFORM
ead91d4b 551 depends on SMP
a7f7f624 552 help
c5c606d9
RT
553 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
554 supposed to run on these EM64T-based machines. Only choose this option
555 if you have one of these machines.
5e3a77e9 556
03b48632
NP
557config X86_UV
558 bool "SGI Ultraviolet"
559 depends on X86_64
c5c606d9 560 depends on X86_EXTENDED_PLATFORM
54c28d29 561 depends on NUMA
1ecb4ae5 562 depends on EFI
9d6c26e7 563 depends on X86_X2APIC
1222e564 564 depends on PCI
a7f7f624 565 help
03b48632
NP
566 This option is needed in order to support SGI Ultraviolet systems.
567 If you don't have one of these, you should say N here.
568
c5c606d9
RT
569# Following is an alphabetically sorted list of 32 bit extended platforms
570# Please maintain the alphabetic order if and when there are additions
506f1d07 571
ddd70cf9 572config X86_GOLDFISH
b03b016f
KK
573 bool "Goldfish (Virtual Platform)"
574 depends on X86_EXTENDED_PLATFORM
a7f7f624 575 help
ddd70cf9
JN
576 Enable support for the Goldfish virtual platform used primarily
577 for Android development. Unless you are building for the Android
578 Goldfish emulator say N here.
579
c751e17b
TG
580config X86_INTEL_CE
581 bool "CE4100 TV platform"
582 depends on PCI
583 depends on PCI_GODIRECT
6084a6e2 584 depends on X86_IO_APIC
c751e17b
TG
585 depends on X86_32
586 depends on X86_EXTENDED_PLATFORM
37bc9f50 587 select X86_REBOOTFIXUPS
da6b737b
SAS
588 select OF
589 select OF_EARLY_FLATTREE
a7f7f624 590 help
c751e17b
TG
591 Select for the Intel CE media processor (CE4100) SOC.
592 This option compiles in support for the CE4100 SOC for settop
593 boxes and media devices.
594
4cb9b00f 595config X86_INTEL_MID
43605ef1 596 bool "Intel MID platform support"
43605ef1 597 depends on X86_EXTENDED_PLATFORM
edc6bc78 598 depends on X86_PLATFORM_DEVICES
1ea7c673 599 depends on PCI
3fda5bb4 600 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 601 depends on X86_IO_APIC
7c9c3a1e 602 select SFI
4cb9b00f 603 select I2C
7c9c3a1e 604 select DW_APB_TIMER
1ea7c673 605 select APB_TIMER
54b34aa0 606 select INTEL_SCU_PCI
15a713df 607 select MFD_INTEL_MSIC
a7f7f624 608 help
4cb9b00f
DC
609 Select to build a kernel capable of supporting Intel MID (Mobile
610 Internet Device) platform systems which do not have the PCI legacy
611 interfaces. If you are building for a PC class system say N here.
1ea7c673 612
4cb9b00f
DC
613 Intel MID platforms are based on an Intel processor and chipset which
614 consume less power than most of the x86 derivatives.
43605ef1 615
8bbc2a13
BD
616config X86_INTEL_QUARK
617 bool "Intel Quark platform support"
618 depends on X86_32
619 depends on X86_EXTENDED_PLATFORM
620 depends on X86_PLATFORM_DEVICES
621 depends on X86_TSC
622 depends on PCI
623 depends on PCI_GOANY
624 depends on X86_IO_APIC
625 select IOSF_MBI
626 select INTEL_IMR
9ab6eb51 627 select COMMON_CLK
a7f7f624 628 help
8bbc2a13
BD
629 Select to include support for Quark X1000 SoC.
630 Say Y here if you have a Quark based system such as the Arduino
631 compatible Intel Galileo.
632
3d48aab1
MW
633config X86_INTEL_LPSS
634 bool "Intel Low Power Subsystem Support"
5962dd22 635 depends on X86 && ACPI && PCI
3d48aab1 636 select COMMON_CLK
0f531431 637 select PINCTRL
eebb3e8d 638 select IOSF_MBI
a7f7f624 639 help
3d48aab1
MW
640 Select to build support for Intel Low Power Subsystem such as
641 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
642 things like clock tree (common clock framework) and pincontrol
643 which are needed by the LPSS peripheral drivers.
3d48aab1 644
92082a88
KX
645config X86_AMD_PLATFORM_DEVICE
646 bool "AMD ACPI2Platform devices support"
647 depends on ACPI
648 select COMMON_CLK
649 select PINCTRL
a7f7f624 650 help
92082a88
KX
651 Select to interpret AMD specific ACPI device to platform device
652 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
653 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
654 implemented under PINCTRL subsystem.
655
ced3ce76
DB
656config IOSF_MBI
657 tristate "Intel SoC IOSF Sideband support for SoC platforms"
658 depends on PCI
a7f7f624 659 help
ced3ce76
DB
660 This option enables sideband register access support for Intel SoC
661 platforms. On these platforms the IOSF sideband is used in lieu of
662 MSR's for some register accesses, mostly but not limited to thermal
663 and power. Drivers may query the availability of this device to
664 determine if they need the sideband in order to work on these
665 platforms. The sideband is available on the following SoC products.
666 This list is not meant to be exclusive.
667 - BayTrail
668 - Braswell
669 - Quark
670
671 You should say Y if you are running a kernel on one of these SoC's.
672
ed2226bd
DB
673config IOSF_MBI_DEBUG
674 bool "Enable IOSF sideband access through debugfs"
675 depends on IOSF_MBI && DEBUG_FS
a7f7f624 676 help
ed2226bd
DB
677 Select this option to expose the IOSF sideband access registers (MCR,
678 MDR, MCRX) through debugfs to write and read register information from
679 different units on the SoC. This is most useful for obtaining device
680 state information for debug and analysis. As this is a general access
681 mechanism, users of this option would have specific knowledge of the
682 device they want to access.
683
684 If you don't require the option or are in doubt, say N.
685
c5c606d9
RT
686config X86_RDC321X
687 bool "RDC R-321x SoC"
506f1d07 688 depends on X86_32
c5c606d9
RT
689 depends on X86_EXTENDED_PLATFORM
690 select M486
691 select X86_REBOOTFIXUPS
a7f7f624 692 help
c5c606d9
RT
693 This option is needed for RDC R-321x system-on-chip, also known
694 as R-8610-(G).
695 If you don't have one of these chips, you should say N here.
696
e0c7ae37 697config X86_32_NON_STANDARD
9c398017
IM
698 bool "Support non-standard 32-bit SMP architectures"
699 depends on X86_32 && SMP
c5c606d9 700 depends on X86_EXTENDED_PLATFORM
a7f7f624 701 help
b5660ba7
PA
702 This option compiles in the bigsmp and STA2X11 default
703 subarchitectures. It is intended for a generic binary
704 kernel. If you select them all, kernel will probe it one by
705 one and will fallback to default.
d49c4288 706
c5c606d9 707# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 708
d949f36f 709config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 710 def_bool y
d949f36f
LT
711 # MCE code calls memory_failure():
712 depends on X86_MCE
713 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
714 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
715 depends on X86_64 || !SPARSEMEM
716 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 717
83125a3a
AR
718config STA2X11
719 bool "STA2X11 Companion Chip Support"
720 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
721 select SWIOTLB
722 select MFD_STA2X11
0145071b 723 select GPIOLIB
a7f7f624 724 help
83125a3a
AR
725 This adds support for boards based on the STA2X11 IO-Hub,
726 a.k.a. "ConneXt". The chip is used in place of the standard
727 PC chipset, so all "standard" peripherals are missing. If this
728 option is selected the kernel will still be able to boot on
729 standard PC machines.
730
82148d1d
S
731config X86_32_IRIS
732 tristate "Eurobraille/Iris poweroff module"
733 depends on X86_32
a7f7f624 734 help
82148d1d
S
735 The Iris machines from EuroBraille do not have APM or ACPI support
736 to shut themselves down properly. A special I/O sequence is
737 needed to do so, which is what this module does at
738 kernel shutdown.
739
740 This is only for Iris machines from EuroBraille.
741
742 If unused, say N.
743
ae1e9130 744config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
745 def_bool y
746 prompt "Single-depth WCHAN output"
a87d0914 747 depends on X86
a7f7f624 748 help
506f1d07
SR
749 Calculate simpler /proc/<PID>/wchan values. If this option
750 is disabled then wchan values will recurse back to the
751 caller function. This provides more accurate wchan values,
752 at the expense of slightly more scheduling overhead.
753
754 If in doubt, say "Y".
755
6276a074
BP
756menuconfig HYPERVISOR_GUEST
757 bool "Linux guest support"
a7f7f624 758 help
6276a074
BP
759 Say Y here to enable options for running Linux under various hyper-
760 visors. This option enables basic hypervisor detection and platform
761 setup.
506f1d07 762
6276a074
BP
763 If you say N, all options in this submenu will be skipped and
764 disabled, and Linux guest support won't be built in.
506f1d07 765
6276a074 766if HYPERVISOR_GUEST
506f1d07 767
e61bd94a
EPH
768config PARAVIRT
769 bool "Enable paravirtualization code"
a7f7f624 770 help
e61bd94a
EPH
771 This changes the kernel so it can modify itself when it is run
772 under a hypervisor, potentially improving performance significantly
773 over full virtualization. However, when run without a hypervisor
774 the kernel is theoretically slower and slightly larger.
775
c00a280a
JG
776config PARAVIRT_XXL
777 bool
778
6276a074
BP
779config PARAVIRT_DEBUG
780 bool "paravirt-ops debugging"
781 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 782 help
6276a074
BP
783 Enable to debug paravirt_ops internals. Specifically, BUG if
784 a paravirt_op is missing when it is called.
785
b4ecc126
JF
786config PARAVIRT_SPINLOCKS
787 bool "Paravirtualization layer for spinlocks"
6ea30386 788 depends on PARAVIRT && SMP
a7f7f624 789 help
b4ecc126
JF
790 Paravirtualized spinlocks allow a pvops backend to replace the
791 spinlock implementation with something virtualization-friendly
792 (for example, block the virtual CPU rather than spinning).
793
4c4e4f61
R
794 It has a minimal impact on native kernels and gives a nice performance
795 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 796
4c4e4f61 797 If you are unsure how to answer this question, answer Y.
b4ecc126 798
ecca2502
ZY
799config X86_HV_CALLBACK_VECTOR
800 def_bool n
801
6276a074 802source "arch/x86/xen/Kconfig"
7af192c9 803
6276a074
BP
804config KVM_GUEST
805 bool "KVM Guest support (including kvmclock)"
806 depends on PARAVIRT
807 select PARAVIRT_CLOCK
a1c4423b 808 select ARCH_CPUIDLE_HALTPOLL
b1d40575 809 select X86_HV_CALLBACK_VECTOR
6276a074 810 default y
a7f7f624 811 help
6276a074
BP
812 This option enables various optimizations for running under the KVM
813 hypervisor. It includes a paravirtualized clock, so that instead
814 of relying on a PIT (or probably other) emulation by the
815 underlying device model, the host provides the guest with
816 timing infrastructure such as time of day, and system time
506f1d07 817
a1c4423b 818config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
819 def_bool n
820 prompt "Disable host haltpoll when loading haltpoll driver"
821 help
a1c4423b
MT
822 If virtualized under KVM, disable host haltpoll.
823
7733607f
MW
824config PVH
825 bool "Support for running PVH guests"
a7f7f624 826 help
7733607f
MW
827 This option enables the PVH entry point for guest virtual machines
828 as specified in the x86/HVM direct boot ABI.
829
6276a074
BP
830config PARAVIRT_TIME_ACCOUNTING
831 bool "Paravirtual steal time accounting"
832 depends on PARAVIRT
a7f7f624 833 help
6276a074
BP
834 Select this option to enable fine granularity task steal time
835 accounting. Time spent executing other tasks in parallel with
836 the current vCPU is discounted from the vCPU power. To account for
837 that, there can be a small performance impact.
838
839 If in doubt, say N here.
840
841config PARAVIRT_CLOCK
842 bool
97349135 843
4a362601
JK
844config JAILHOUSE_GUEST
845 bool "Jailhouse non-root cell support"
abde587b 846 depends on X86_64 && PCI
87e65d05 847 select X86_PM_TIMER
a7f7f624 848 help
4a362601
JK
849 This option allows to run Linux as guest in a Jailhouse non-root
850 cell. You can leave this option disabled if you only want to start
851 Jailhouse and run Linux afterwards in the root cell.
852
ec7972c9
ZY
853config ACRN_GUEST
854 bool "ACRN Guest support"
855 depends on X86_64
498ad393 856 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
857 help
858 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
859 a flexible, lightweight reference open-source hypervisor, built with
860 real-time and safety-criticality in mind. It is built for embedded
861 IOT with small footprint and real-time features. More details can be
862 found in https://projectacrn.org/.
863
6276a074 864endif #HYPERVISOR_GUEST
97349135 865
506f1d07
SR
866source "arch/x86/Kconfig.cpu"
867
868config HPET_TIMER
3c2362e6 869 def_bool X86_64
506f1d07 870 prompt "HPET Timer Support" if X86_32
a7f7f624 871 help
8f9ca475
IM
872 Use the IA-PC HPET (High Precision Event Timer) to manage
873 time in preference to the PIT and RTC, if a HPET is
874 present.
875 HPET is the next generation timer replacing legacy 8254s.
876 The HPET provides a stable time base on SMP
877 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
878 as it is off-chip. The interface used is documented
879 in the HPET spec, revision 1.
506f1d07 880
8f9ca475
IM
881 You can safely choose Y here. However, HPET will only be
882 activated if the platform and the BIOS support this feature.
883 Otherwise the 8254 will be used for timing services.
506f1d07 884
8f9ca475 885 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
886
887config HPET_EMULATE_RTC
3c2362e6 888 def_bool y
9d8af78b 889 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 890
bb24c471 891config APB_TIMER
b03b016f
KK
892 def_bool y if X86_INTEL_MID
893 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
894 select DW_APB_TIMER
895 depends on X86_INTEL_MID && SFI
896 help
897 APB timer is the replacement for 8254, HPET on X86 MID platforms.
898 The APBT provides a stable time base on SMP
899 systems, unlike the TSC, but it is more expensive to access,
900 as it is off-chip. APB timers are always running regardless of CPU
901 C states, they are used as per CPU clockevent device when possible.
bb24c471 902
6a108a14 903# Mark as expert because too many people got it wrong.
506f1d07 904# The code disables itself when not needed.
7ae9392c
TP
905config DMI
906 default y
cf074402 907 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 908 bool "Enable DMI scanning" if EXPERT
a7f7f624 909 help
7ae9392c
TP
910 Enabled scanning of DMI to identify machine quirks. Say Y
911 here unless you have verified that your setup is not
912 affected by entries in the DMI blacklist. Required by PNP
913 BIOS code.
914
506f1d07 915config GART_IOMMU
38901f1c 916 bool "Old AMD GART IOMMU support"
2f9237d4 917 select DMA_OPS
a4ce5a48 918 select IOMMU_HELPER
506f1d07 919 select SWIOTLB
23ac4ae8 920 depends on X86_64 && PCI && AMD_NB
a7f7f624 921 help
ced3c42c
IM
922 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
923 GART based hardware IOMMUs.
924
925 The GART supports full DMA access for devices with 32-bit access
926 limitations, on systems with more than 3 GB. This is usually needed
927 for USB, sound, many IDE/SATA chipsets and some other devices.
928
929 Newer systems typically have a modern AMD IOMMU, supported via
930 the CONFIG_AMD_IOMMU=y config option.
931
932 In normal configurations this driver is only active when needed:
933 there's more than 3 GB of memory and the system contains a
934 32-bit limited device.
935
936 If unsure, say Y.
506f1d07 937
1184dc2f 938config MAXSMP
ddb0c5a6 939 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 940 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 941 select CPUMASK_OFFSTACK
a7f7f624 942 help
ddb0c5a6 943 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 944 If unsure, say N.
506f1d07 945
aec6487e
IM
946#
947# The maximum number of CPUs supported:
948#
949# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
950# and which can be configured interactively in the
951# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
952#
953# The ranges are different on 32-bit and 64-bit kernels, depending on
954# hardware capabilities and scalability features of the kernel.
955#
956# ( If MAXSMP is enabled we just use the highest possible value and disable
957# interactive configuration. )
958#
959
960config NR_CPUS_RANGE_BEGIN
a0d0bb4d 961 int
aec6487e
IM
962 default NR_CPUS_RANGE_END if MAXSMP
963 default 1 if !SMP
964 default 2
a0d0bb4d 965
aec6487e 966config NR_CPUS_RANGE_END
a0d0bb4d 967 int
aec6487e
IM
968 depends on X86_32
969 default 64 if SMP && X86_BIGSMP
970 default 8 if SMP && !X86_BIGSMP
971 default 1 if !SMP
a0d0bb4d 972
aec6487e 973config NR_CPUS_RANGE_END
a0d0bb4d 974 int
aec6487e 975 depends on X86_64
1edae1ae
SW
976 default 8192 if SMP && CPUMASK_OFFSTACK
977 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 978 default 1 if !SMP
a0d0bb4d 979
aec6487e 980config NR_CPUS_DEFAULT
a0d0bb4d
RD
981 int
982 depends on X86_32
aec6487e
IM
983 default 32 if X86_BIGSMP
984 default 8 if SMP
985 default 1 if !SMP
a0d0bb4d 986
aec6487e 987config NR_CPUS_DEFAULT
a0d0bb4d
RD
988 int
989 depends on X86_64
aec6487e
IM
990 default 8192 if MAXSMP
991 default 64 if SMP
992 default 1 if !SMP
a0d0bb4d 993
506f1d07 994config NR_CPUS
36f5101a 995 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
996 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
997 default NR_CPUS_DEFAULT
a7f7f624 998 help
506f1d07 999 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1000 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1001 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1002 minimum value which makes sense is 2.
1003
aec6487e
IM
1004 This is purely to save memory: each supported CPU adds about 8KB
1005 to the kernel image.
506f1d07
SR
1006
1007config SCHED_SMT
dbe73364 1008 def_bool y if SMP
506f1d07
SR
1009
1010config SCHED_MC
3c2362e6
HH
1011 def_bool y
1012 prompt "Multi-core scheduler support"
c8e56d20 1013 depends on SMP
a7f7f624 1014 help
506f1d07
SR
1015 Multi-core scheduler support improves the CPU scheduler's decision
1016 making when dealing with multi-core CPU chips at a cost of slightly
1017 increased overhead in some places. If unsure say N here.
1018
de966cf4
TC
1019config SCHED_MC_PRIO
1020 bool "CPU core priorities scheduler support"
0a21fc12
IM
1021 depends on SCHED_MC && CPU_SUP_INTEL
1022 select X86_INTEL_PSTATE
1023 select CPU_FREQ
de966cf4 1024 default y
a7f7f624 1025 help
0a21fc12
IM
1026 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1027 core ordering determined at manufacturing time, which allows
1028 certain cores to reach higher turbo frequencies (when running
1029 single threaded workloads) than others.
de966cf4 1030
0a21fc12
IM
1031 Enabling this kernel feature teaches the scheduler about
1032 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1033 scheduler's CPU selection logic accordingly, so that higher
1034 overall system performance can be achieved.
de966cf4 1035
0a21fc12 1036 This feature will have no effect on CPUs without this feature.
de966cf4 1037
0a21fc12 1038 If unsure say Y here.
5e76b2ab 1039
30b8b006 1040config UP_LATE_INIT
b03b016f
KK
1041 def_bool y
1042 depends on !SMP && X86_LOCAL_APIC
30b8b006 1043
506f1d07 1044config X86_UP_APIC
50849eef
JB
1045 bool "Local APIC support on uniprocessors" if !PCI_MSI
1046 default PCI_MSI
38a1dfda 1047 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1048 help
506f1d07
SR
1049 A local APIC (Advanced Programmable Interrupt Controller) is an
1050 integrated interrupt controller in the CPU. If you have a single-CPU
1051 system which has a processor with a local APIC, you can say Y here to
1052 enable and use it. If you say Y here even though your machine doesn't
1053 have a local APIC, then the kernel will still run with no slowdown at
1054 all. The local APIC supports CPU-generated self-interrupts (timer,
1055 performance counters), and the NMI watchdog which detects hard
1056 lockups.
1057
1058config X86_UP_IOAPIC
1059 bool "IO-APIC support on uniprocessors"
1060 depends on X86_UP_APIC
a7f7f624 1061 help
506f1d07
SR
1062 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1063 SMP-capable replacement for PC-style interrupt controllers. Most
1064 SMP systems and many recent uniprocessor systems have one.
1065
1066 If you have a single-CPU system with an IO-APIC, you can say Y here
1067 to use it. If you say Y here even though your machine doesn't have
1068 an IO-APIC, then the kernel will still run with no slowdown at all.
1069
1070config X86_LOCAL_APIC
3c2362e6 1071 def_bool y
0dbc6078 1072 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1073 select IRQ_DOMAIN_HIERARCHY
52f518a3 1074 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
506f1d07
SR
1075
1076config X86_IO_APIC
b1da1e71
JB
1077 def_bool y
1078 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1079
41b9eb26
SA
1080config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1081 bool "Reroute for broken boot IRQs"
41b9eb26 1082 depends on X86_IO_APIC
a7f7f624 1083 help
41b9eb26
SA
1084 This option enables a workaround that fixes a source of
1085 spurious interrupts. This is recommended when threaded
1086 interrupt handling is used on systems where the generation of
1087 superfluous "boot interrupts" cannot be disabled.
1088
1089 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1090 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1091 kernel does during interrupt handling). On chipsets where this
1092 boot IRQ generation cannot be disabled, this workaround keeps
1093 the original IRQ line masked so that only the equivalent "boot
1094 IRQ" is delivered to the CPUs. The workaround also tells the
1095 kernel to set up the IRQ handler on the boot IRQ line. In this
1096 way only one interrupt is delivered to the kernel. Otherwise
1097 the spurious second interrupt may cause the kernel to bring
1098 down (vital) interrupt lines.
1099
1100 Only affects "broken" chipsets. Interrupt sharing may be
1101 increased on these systems.
1102
506f1d07 1103config X86_MCE
bab9bc65 1104 bool "Machine Check / overheating reporting"
648ed940 1105 select GENERIC_ALLOCATOR
e57dbaf7 1106 default y
a7f7f624 1107 help
bab9bc65
AK
1108 Machine Check support allows the processor to notify the
1109 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1110 The action the kernel takes depends on the severity of the problem,
bab9bc65 1111 ranging from warning messages to halting the machine.
4efc0670 1112
5de97c9f
TL
1113config X86_MCELOG_LEGACY
1114 bool "Support for deprecated /dev/mcelog character device"
1115 depends on X86_MCE
a7f7f624 1116 help
5de97c9f
TL
1117 Enable support for /dev/mcelog which is needed by the old mcelog
1118 userspace logging daemon. Consider switching to the new generation
1119 rasdaemon solution.
1120
506f1d07 1121config X86_MCE_INTEL
3c2362e6
HH
1122 def_bool y
1123 prompt "Intel MCE features"
c1ebf835 1124 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1125 help
506f1d07
SR
1126 Additional support for intel specific MCE features such as
1127 the thermal monitor.
1128
1129config X86_MCE_AMD
3c2362e6
HH
1130 def_bool y
1131 prompt "AMD MCE features"
f5382de9 1132 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
a7f7f624 1133 help
506f1d07
SR
1134 Additional support for AMD specific MCE features such as
1135 the DRAM Error Threshold.
1136
4efc0670 1137config X86_ANCIENT_MCE
6fc108a0 1138 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1139 depends on X86_32 && X86_MCE
a7f7f624 1140 help
cd13adcc 1141 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1142 systems. These typically need to be enabled explicitly on the command
cd13adcc 1143 line.
4efc0670 1144
b2762686
AK
1145config X86_MCE_THRESHOLD
1146 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1147 def_bool y
b2762686 1148
ea149b36 1149config X86_MCE_INJECT
bc8e80d5 1150 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1151 tristate "Machine check injector support"
a7f7f624 1152 help
ea149b36
AK
1153 Provide support for injecting machine checks for testing purposes.
1154 If you don't know what a machine check is and you don't do kernel
1155 QA it is safe to say n.
1156
4efc0670
AK
1157config X86_THERMAL_VECTOR
1158 def_bool y
5bb38adc 1159 depends on X86_MCE_INTEL
4efc0670 1160
07dc900e 1161source "arch/x86/events/Kconfig"
e633c65a 1162
5aef51c3 1163config X86_LEGACY_VM86
1e642812 1164 bool "Legacy VM86 support"
506f1d07 1165 depends on X86_32
a7f7f624 1166 help
5aef51c3
AL
1167 This option allows user programs to put the CPU into V8086
1168 mode, which is an 80286-era approximation of 16-bit real mode.
1169
1170 Some very old versions of X and/or vbetool require this option
1171 for user mode setting. Similarly, DOSEMU will use it if
1172 available to accelerate real mode DOS programs. However, any
1173 recent version of DOSEMU, X, or vbetool should be fully
1174 functional even without kernel VM86 support, as they will all
1e642812
IM
1175 fall back to software emulation. Nevertheless, if you are using
1176 a 16-bit DOS program where 16-bit performance matters, vm86
1177 mode might be faster than emulation and you might want to
1178 enable this option.
5aef51c3 1179
1e642812
IM
1180 Note that any app that works on a 64-bit kernel is unlikely to
1181 need this option, as 64-bit kernels don't, and can't, support
1182 V8086 mode. This option is also unrelated to 16-bit protected
1183 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1184
1e642812
IM
1185 Enabling this option increases the complexity of the kernel
1186 and slows down exception handling a tiny bit.
5aef51c3 1187
1e642812 1188 If unsure, say N here.
5aef51c3
AL
1189
1190config VM86
b03b016f
KK
1191 bool
1192 default X86_LEGACY_VM86
34273f41
PA
1193
1194config X86_16BIT
1195 bool "Enable support for 16-bit segments" if EXPERT
1196 default y
a5b9e5a2 1197 depends on MODIFY_LDT_SYSCALL
a7f7f624 1198 help
34273f41
PA
1199 This option is required by programs like Wine to run 16-bit
1200 protected mode legacy code on x86 processors. Disabling
1201 this option saves about 300 bytes on i386, or around 6K text
1202 plus 16K runtime memory on x86-64,
1203
1204config X86_ESPFIX32
1205 def_bool y
1206 depends on X86_16BIT && X86_32
506f1d07 1207
197725de
PA
1208config X86_ESPFIX64
1209 def_bool y
34273f41 1210 depends on X86_16BIT && X86_64
506f1d07 1211
1ad83c85 1212config X86_VSYSCALL_EMULATION
b03b016f
KK
1213 bool "Enable vsyscall emulation" if EXPERT
1214 default y
1215 depends on X86_64
a7f7f624 1216 help
1ad83c85
AL
1217 This enables emulation of the legacy vsyscall page. Disabling
1218 it is roughly equivalent to booting with vsyscall=none, except
1219 that it will also disable the helpful warning if a program
1220 tries to use a vsyscall. With this option set to N, offending
1221 programs will just segfault, citing addresses of the form
1222 0xffffffffff600?00.
1223
1224 This option is required by many programs built before 2013, and
1225 care should be used even with newer programs if set to N.
1226
1227 Disabling this option saves about 7K of kernel size and
1228 possibly 4K of additional runtime pagetable memory.
1229
111e7b15
TG
1230config X86_IOPL_IOPERM
1231 bool "IOPERM and IOPL Emulation"
a24ca997 1232 default y
a7f7f624 1233 help
111e7b15
TG
1234 This enables the ioperm() and iopl() syscalls which are necessary
1235 for legacy applications.
1236
c8137ace
TG
1237 Legacy IOPL support is an overbroad mechanism which allows user
1238 space aside of accessing all 65536 I/O ports also to disable
1239 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1240 capabilities and permission from potentially active security
1241 modules.
1242
1243 The emulation restricts the functionality of the syscall to
1244 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1245 ability to disable interrupts from user space which would be
1246 granted if the hardware IOPL mechanism would be used.
c8137ace 1247
506f1d07
SR
1248config TOSHIBA
1249 tristate "Toshiba Laptop support"
1250 depends on X86_32
a7f7f624 1251 help
506f1d07
SR
1252 This adds a driver to safely access the System Management Mode of
1253 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1254 not work on models with a Phoenix BIOS. The System Management Mode
1255 is used to set the BIOS and power saving options on Toshiba portables.
1256
1257 For information on utilities to make use of this driver see the
1258 Toshiba Linux utilities web site at:
1259 <http://www.buzzard.org.uk/toshiba/>.
1260
1261 Say Y if you intend to run this kernel on a Toshiba portable.
1262 Say N otherwise.
1263
1264config I8K
039ae585 1265 tristate "Dell i8k legacy laptop support"
949a9d70 1266 select HWMON
039ae585 1267 select SENSORS_DELL_SMM
a7f7f624 1268 help
039ae585
PR
1269 This option enables legacy /proc/i8k userspace interface in hwmon
1270 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1271 temperature and allows controlling fan speeds of Dell laptops via
1272 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1273 it reports also power and hotkey status. For fan speed control is
1274 needed userspace package i8kutils.
1275
1276 Say Y if you intend to run this kernel on old Dell laptops or want to
1277 use userspace package i8kutils.
506f1d07
SR
1278 Say N otherwise.
1279
1280config X86_REBOOTFIXUPS
9ba16087
JB
1281 bool "Enable X86 board specific fixups for reboot"
1282 depends on X86_32
a7f7f624 1283 help
506f1d07
SR
1284 This enables chipset and/or board specific fixups to be done
1285 in order to get reboot to work correctly. This is only needed on
1286 some combinations of hardware and BIOS. The symptom, for which
1287 this config is intended, is when reboot ends with a stalled/hung
1288 system.
1289
1290 Currently, the only fixup is for the Geode machines using
5e3a77e9 1291 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1292
1293 Say Y if you want to enable the fixup. Currently, it's safe to
1294 enable this option even if you don't need it.
1295 Say N otherwise.
1296
1297config MICROCODE
9a2bc335
BP
1298 bool "CPU microcode loading support"
1299 default y
80030e3d 1300 depends on CPU_SUP_AMD || CPU_SUP_INTEL
a7f7f624 1301 help
506f1d07 1302 If you say Y here, you will be able to update the microcode on
5f9c01aa
BP
1303 Intel and AMD processors. The Intel support is for the IA32 family,
1304 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1305 AMD support is for families 0x10 and later. You will obviously need
1306 the actual microcode binary data itself which is not shipped with
1307 the Linux kernel.
1308
1309 The preferred method to load microcode from a detached initrd is described
cb1aaebe 1310 in Documentation/x86/microcode.rst. For that you need to enable
5f9c01aa
BP
1311 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1312 initrd for microcode blobs.
1313
c508c46e
BG
1314 In addition, you can build the microcode into the kernel. For that you
1315 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1316 config option.
506f1d07 1317
8d86f390 1318config MICROCODE_INTEL
e43f6e67 1319 bool "Intel microcode loading support"
8f9ca475
IM
1320 depends on MICROCODE
1321 default MICROCODE
a7f7f624 1322 help
8f9ca475
IM
1323 This options enables microcode patch loading support for Intel
1324 processors.
1325
b8989db9
A
1326 For the current Intel microcode data package go to
1327 <https://downloadcenter.intel.com> and search for
1328 'Linux Processor Microcode Data File'.
8d86f390 1329
80cc9f10 1330config MICROCODE_AMD
e43f6e67 1331 bool "AMD microcode loading support"
8f9ca475 1332 depends on MICROCODE
a7f7f624 1333 help
8f9ca475
IM
1334 If you select this option, microcode patch loading support for AMD
1335 processors will be enabled.
80cc9f10 1336
8f9ca475 1337config MICROCODE_OLD_INTERFACE
c02f48e0
BP
1338 bool "Ancient loading interface (DEPRECATED)"
1339 default n
506f1d07 1340 depends on MICROCODE
a7f7f624 1341 help
c02f48e0
BP
1342 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1343 which was used by userspace tools like iucode_tool and microcode.ctl.
1344 It is inadequate because it runs too late to be able to properly
1345 load microcode on a machine and it needs special tools. Instead, you
1346 should've switched to the early loading method with the initrd or
cb1aaebe 1347 builtin microcode by now: Documentation/x86/microcode.rst
506f1d07
SR
1348
1349config X86_MSR
1350 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1351 help
506f1d07
SR
1352 This device gives privileged processes access to the x86
1353 Model-Specific Registers (MSRs). It is a character device with
1354 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1355 MSR accesses are directed to a specific CPU on multi-processor
1356 systems.
1357
1358config X86_CPUID
1359 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1360 help
506f1d07
SR
1361 This device gives processes access to the x86 CPUID instruction to
1362 be executed on a specific processor. It is a character device
1363 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1364 /dev/cpu/31/cpuid.
1365
1366choice
1367 prompt "High Memory Support"
6fc108a0 1368 default HIGHMEM4G
506f1d07
SR
1369 depends on X86_32
1370
1371config NOHIGHMEM
1372 bool "off"
a7f7f624 1373 help
506f1d07
SR
1374 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1375 However, the address space of 32-bit x86 processors is only 4
1376 Gigabytes large. That means that, if you have a large amount of
1377 physical memory, not all of it can be "permanently mapped" by the
1378 kernel. The physical memory that's not permanently mapped is called
1379 "high memory".
1380
1381 If you are compiling a kernel which will never run on a machine with
1382 more than 1 Gigabyte total physical RAM, answer "off" here (default
1383 choice and suitable for most users). This will result in a "3GB/1GB"
1384 split: 3GB are mapped so that each process sees a 3GB virtual memory
1385 space and the remaining part of the 4GB virtual memory space is used
1386 by the kernel to permanently map as much physical memory as
1387 possible.
1388
1389 If the machine has between 1 and 4 Gigabytes physical RAM, then
1390 answer "4GB" here.
1391
1392 If more than 4 Gigabytes is used then answer "64GB" here. This
1393 selection turns Intel PAE (Physical Address Extension) mode on.
1394 PAE implements 3-level paging on IA32 processors. PAE is fully
1395 supported by Linux, PAE mode is implemented on all recent Intel
1396 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1397 then the kernel will not boot on CPUs that don't support PAE!
1398
1399 The actual amount of total physical memory will either be
1400 auto detected or can be forced by using a kernel command line option
1401 such as "mem=256M". (Try "man bootparam" or see the documentation of
1402 your boot loader (lilo or loadlin) about how to pass options to the
1403 kernel at boot time.)
1404
1405 If unsure, say "off".
1406
1407config HIGHMEM4G
1408 bool "4GB"
a7f7f624 1409 help
506f1d07
SR
1410 Select this if you have a 32-bit processor and between 1 and 4
1411 gigabytes of physical RAM.
1412
1413config HIGHMEM64G
1414 bool "64GB"
69b8d3fc 1415 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
506f1d07 1416 select X86_PAE
a7f7f624 1417 help
506f1d07
SR
1418 Select this if you have a 32-bit processor and more than 4
1419 gigabytes of physical RAM.
1420
1421endchoice
1422
1423choice
6a108a14 1424 prompt "Memory split" if EXPERT
506f1d07
SR
1425 default VMSPLIT_3G
1426 depends on X86_32
a7f7f624 1427 help
506f1d07
SR
1428 Select the desired split between kernel and user memory.
1429
1430 If the address range available to the kernel is less than the
1431 physical memory installed, the remaining memory will be available
1432 as "high memory". Accessing high memory is a little more costly
1433 than low memory, as it needs to be mapped into the kernel first.
1434 Note that increasing the kernel address space limits the range
1435 available to user programs, making the address space there
1436 tighter. Selecting anything other than the default 3G/1G split
1437 will also likely make your kernel incompatible with binary-only
1438 kernel modules.
1439
1440 If you are not absolutely sure what you are doing, leave this
1441 option alone!
1442
1443 config VMSPLIT_3G
1444 bool "3G/1G user/kernel split"
1445 config VMSPLIT_3G_OPT
1446 depends on !X86_PAE
1447 bool "3G/1G user/kernel split (for full 1G low memory)"
1448 config VMSPLIT_2G
1449 bool "2G/2G user/kernel split"
1450 config VMSPLIT_2G_OPT
1451 depends on !X86_PAE
1452 bool "2G/2G user/kernel split (for full 2G low memory)"
1453 config VMSPLIT_1G
1454 bool "1G/3G user/kernel split"
1455endchoice
1456
1457config PAGE_OFFSET
1458 hex
1459 default 0xB0000000 if VMSPLIT_3G_OPT
1460 default 0x80000000 if VMSPLIT_2G
1461 default 0x78000000 if VMSPLIT_2G_OPT
1462 default 0x40000000 if VMSPLIT_1G
1463 default 0xC0000000
1464 depends on X86_32
1465
1466config HIGHMEM
3c2362e6 1467 def_bool y
506f1d07 1468 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1469
1470config X86_PAE
9ba16087 1471 bool "PAE (Physical Address Extension) Support"
506f1d07 1472 depends on X86_32 && !HIGHMEM4G
d4a451d5 1473 select PHYS_ADDR_T_64BIT
9d99c712 1474 select SWIOTLB
a7f7f624 1475 help
506f1d07
SR
1476 PAE is required for NX support, and furthermore enables
1477 larger swapspace support for non-overcommit purposes. It
1478 has the cost of more pagetable lookup overhead, and also
1479 consumes more pagetable space per process.
1480
77ef56e4
KS
1481config X86_5LEVEL
1482 bool "Enable 5-level page tables support"
18ec1eaf 1483 default y
eedb92ab 1484 select DYNAMIC_MEMORY_LAYOUT
162434e7 1485 select SPARSEMEM_VMEMMAP
77ef56e4 1486 depends on X86_64
a7f7f624 1487 help
77ef56e4
KS
1488 5-level paging enables access to larger address space:
1489 upto 128 PiB of virtual address space and 4 PiB of
1490 physical address space.
1491
1492 It will be supported by future Intel CPUs.
1493
6657fca0
KS
1494 A kernel with the option enabled can be booted on machines that
1495 support 4- or 5-level paging.
77ef56e4 1496
cb1aaebe 1497 See Documentation/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1498 information.
1499
1500 Say N if unsure.
1501
10971ab2 1502config X86_DIRECT_GBPAGES
e5008abe 1503 def_bool y
2e1da13f 1504 depends on X86_64
a7f7f624 1505 help
10971ab2
IM
1506 Certain kernel features effectively disable kernel
1507 linear 1 GB mappings (even if the CPU otherwise
1508 supports them), so don't confuse the user by printing
1509 that we have them enabled.
9e899816 1510
5c280cf6
TG
1511config X86_CPA_STATISTICS
1512 bool "Enable statistic for Change Page Attribute"
1513 depends on DEBUG_FS
a7f7f624 1514 help
b75baaf3 1515 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1516 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1517 page mappings when mapping protections are changed.
1518
7744ccdb
TL
1519config AMD_MEM_ENCRYPT
1520 bool "AMD Secure Memory Encryption (SME) support"
1521 depends on X86_64 && CPU_SUP_AMD
82fef0ad 1522 select DMA_COHERENT_POOL
94d49eb3 1523 select DYNAMIC_PHYSICAL_MASK
ce9084ba 1524 select ARCH_USE_MEMREMAP_PROT
9087c375 1525 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
597cfe48 1526 select INSTRUCTION_DECODER
a7f7f624 1527 help
7744ccdb
TL
1528 Say yes to enable support for the encryption of system memory.
1529 This requires an AMD processor that supports Secure Memory
1530 Encryption (SME).
1531
1532config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1533 bool "Activate AMD Secure Memory Encryption (SME) by default"
1534 default y
1535 depends on AMD_MEM_ENCRYPT
a7f7f624 1536 help
7744ccdb
TL
1537 Say yes to have system memory encrypted by default if running on
1538 an AMD processor that supports Secure Memory Encryption (SME).
1539
1540 If set to Y, then the encryption of system memory can be
1541 deactivated with the mem_encrypt=off command line option.
1542
1543 If set to N, then the encryption of system memory can be
1544 activated with the mem_encrypt=on command line option.
1545
506f1d07
SR
1546# Common NUMA Features
1547config NUMA
e133f6ea 1548 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1549 depends on SMP
b5660ba7
PA
1550 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1551 default y if X86_BIGSMP
a7f7f624 1552 help
e133f6ea 1553 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1554
506f1d07
SR
1555 The kernel will try to allocate memory used by a CPU on the
1556 local memory controller of the CPU and add some more
1557 NUMA awareness to the kernel.
1558
c280ea5e 1559 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1560 (or later), AMD Opteron, or EM64T NUMA.
1561
b5660ba7 1562 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1563 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1564
1565 Otherwise, you should say N.
506f1d07 1566
eec1d4fa 1567config AMD_NUMA
3c2362e6
HH
1568 def_bool y
1569 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1570 depends on X86_64 && NUMA && PCI
a7f7f624 1571 help
eec1d4fa
HR
1572 Enable AMD NUMA node topology detection. You should say Y here if
1573 you have a multi processor AMD system. This uses an old method to
1574 read the NUMA configuration directly from the builtin Northbridge
1575 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1576 which also takes priority if both are compiled in.
506f1d07
SR
1577
1578config X86_64_ACPI_NUMA
3c2362e6
HH
1579 def_bool y
1580 prompt "ACPI NUMA detection"
506f1d07
SR
1581 depends on X86_64 && NUMA && ACPI && PCI
1582 select ACPI_NUMA
a7f7f624 1583 help
506f1d07
SR
1584 Enable ACPI SRAT based node topology detection.
1585
1586config NUMA_EMU
1587 bool "NUMA emulation"
1b7e03ef 1588 depends on NUMA
a7f7f624 1589 help
506f1d07
SR
1590 Enable NUMA emulation. A flat machine will be split
1591 into virtual nodes when booted with "numa=fake=N", where N is the
1592 number of nodes. This is only useful for debugging.
1593
1594config NODES_SHIFT
d25e26b6 1595 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1596 range 1 10
1597 default "10" if MAXSMP
506f1d07 1598 default "6" if X86_64
506f1d07
SR
1599 default "3"
1600 depends on NEED_MULTIPLE_NODES
a7f7f624 1601 help
1184dc2f 1602 Specify the maximum number of NUMA Nodes available on the target
692105b8 1603 system. Increases memory reserved to accommodate various tables.
506f1d07 1604
506f1d07
SR
1605config ARCH_FLATMEM_ENABLE
1606 def_bool y
3b16651f 1607 depends on X86_32 && !NUMA
506f1d07 1608
506f1d07
SR
1609config ARCH_SPARSEMEM_ENABLE
1610 def_bool y
6ea30386 1611 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1612 select SPARSEMEM_STATIC if X86_32
1613 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1614
3b16651f 1615config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1616 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1617
506f1d07
SR
1618config ARCH_SELECT_MEMORY_MODEL
1619 def_bool y
b263295d 1620 depends on ARCH_SPARSEMEM_ENABLE
506f1d07
SR
1621
1622config ARCH_MEMORY_PROBE
a0842b70 1623 bool "Enable sysfs memory/probe interface"
3120e25e 1624 depends on X86_64 && MEMORY_HOTPLUG
a0842b70
TK
1625 help
1626 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1627 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1628 If you are unsure how to answer this question, answer N.
506f1d07 1629
3b16651f
TH
1630config ARCH_PROC_KCORE_TEXT
1631 def_bool y
1632 depends on X86_64 && PROC_KCORE
1633
a29815a3 1634config ILLEGAL_POINTER_VALUE
b03b016f
KK
1635 hex
1636 default 0 if X86_32
1637 default 0xdead000000000000 if X86_64
a29815a3 1638
7a67832c
DW
1639config X86_PMEM_LEGACY_DEVICE
1640 bool
1641
ec776ef6 1642config X86_PMEM_LEGACY
7a67832c 1643 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1644 depends on PHYS_ADDR_T_64BIT
1645 depends on BLK_DEV
7a67832c 1646 select X86_PMEM_LEGACY_DEVICE
7b27a862 1647 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1648 select LIBNVDIMM
ec776ef6
CH
1649 help
1650 Treat memory marked using the non-standard e820 type of 12 as used
1651 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1652 The kernel will offer these regions to the 'pmem' driver so
1653 they can be used for persistent storage.
1654
1655 Say Y if unsure.
1656
506f1d07
SR
1657config HIGHPTE
1658 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1659 depends on HIGHMEM
a7f7f624 1660 help
506f1d07
SR
1661 The VM uses one page table entry for each page of physical memory.
1662 For systems with a lot of RAM, this can be wasteful of precious
1663 low memory. Setting this option will put user-space page table
1664 entries in high memory.
1665
9f077871 1666config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1667 bool "Check for low memory corruption"
a7f7f624 1668 help
8f9ca475
IM
1669 Periodically check for memory corruption in low memory, which
1670 is suspected to be caused by BIOS. Even when enabled in the
1671 configuration, it is disabled at runtime. Enable it by
1672 setting "memory_corruption_check=1" on the kernel command
1673 line. By default it scans the low 64k of memory every 60
1674 seconds; see the memory_corruption_check_size and
1675 memory_corruption_check_period parameters in
8c27ceff 1676 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1677
1678 When enabled with the default parameters, this option has
1679 almost no overhead, as it reserves a relatively small amount
1680 of memory and scans it infrequently. It both detects corruption
1681 and prevents it from affecting the running system.
1682
1683 It is, however, intended as a diagnostic tool; if repeatable
1684 BIOS-originated corruption always affects the same memory,
1685 you can use memmap= to prevent the kernel from using that
1686 memory.
9f077871 1687
c885df50 1688config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1689 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1690 depends on X86_CHECK_BIOS_CORRUPTION
1691 default y
a7f7f624 1692 help
8f9ca475
IM
1693 Set whether the default state of memory_corruption_check is
1694 on or off.
c885df50 1695
9ea77bdb 1696config X86_RESERVE_LOW
d0cd7425
PA
1697 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1698 default 64
1699 range 4 640
a7f7f624 1700 help
d0cd7425
PA
1701 Specify the amount of low memory to reserve for the BIOS.
1702
1703 The first page contains BIOS data structures that the kernel
1704 must not use, so that page must always be reserved.
1705
1706 By default we reserve the first 64K of physical RAM, as a
1707 number of BIOSes are known to corrupt that memory range
1708 during events such as suspend/resume or monitor cable
1709 insertion, so it must not be used by the kernel.
fc381519 1710
d0cd7425
PA
1711 You can set this to 4 if you are absolutely sure that you
1712 trust the BIOS to get all its memory reservations and usages
1713 right. If you know your BIOS have problems beyond the
1714 default 64K area, you can set this to 640 to avoid using the
1715 entire low memory range.
fc381519 1716
d0cd7425
PA
1717 If you have doubts about the BIOS (e.g. suspend/resume does
1718 not work or there's kernel crashes after certain hardware
1719 hotplug events) then you might want to enable
1720 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1721 typical corruption patterns.
fc381519 1722
d0cd7425 1723 Leave this to the default value of 64 if you are unsure.
fc381519 1724
506f1d07
SR
1725config MATH_EMULATION
1726 bool
a5b9e5a2 1727 depends on MODIFY_LDT_SYSCALL
87d6021b 1728 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1729 help
506f1d07
SR
1730 Linux can emulate a math coprocessor (used for floating point
1731 operations) if you don't have one. 486DX and Pentium processors have
1732 a math coprocessor built in, 486SX and 386 do not, unless you added
1733 a 487DX or 387, respectively. (The messages during boot time can
1734 give you some hints here ["man dmesg"].) Everyone needs either a
1735 coprocessor or this emulation.
1736
1737 If you don't have a math coprocessor, you need to say Y here; if you
1738 say Y here even though you have a coprocessor, the coprocessor will
1739 be used nevertheless. (This behavior can be changed with the kernel
1740 command line option "no387", which comes handy if your coprocessor
1741 is broken. Try "man bootparam" or see the documentation of your boot
1742 loader (lilo or loadlin) about how to pass options to the kernel at
1743 boot time.) This means that it is a good idea to say Y here if you
1744 intend to use this kernel on different machines.
1745
1746 More information about the internals of the Linux math coprocessor
1747 emulation can be found in <file:arch/x86/math-emu/README>.
1748
1749 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1750 kernel, it won't hurt.
1751
1752config MTRR
6fc108a0 1753 def_bool y
6a108a14 1754 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1755 help
506f1d07
SR
1756 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1757 the Memory Type Range Registers (MTRRs) may be used to control
1758 processor access to memory ranges. This is most useful if you have
1759 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1760 allows bus write transfers to be combined into a larger transfer
1761 before bursting over the PCI/AGP bus. This can increase performance
1762 of image write operations 2.5 times or more. Saying Y here creates a
1763 /proc/mtrr file which may be used to manipulate your processor's
1764 MTRRs. Typically the X server should use this.
1765
1766 This code has a reasonably generic interface so that similar
1767 control registers on other processors can be easily supported
1768 as well:
1769
1770 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1771 Registers (ARRs) which provide a similar functionality to MTRRs. For
1772 these, the ARRs are used to emulate the MTRRs.
1773 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1774 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1775 write-combining. All of these processors are supported by this code
1776 and it makes sense to say Y here if you have one of them.
1777
1778 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1779 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1780 can lead to all sorts of problems, so it's good to say Y here.
1781
1782 You can safely say Y even if your machine doesn't have MTRRs, you'll
1783 just add about 9 KB to your kernel.
1784
cb1aaebe 1785 See <file:Documentation/x86/mtrr.rst> for more information.
506f1d07 1786
95ffa243 1787config MTRR_SANITIZER
2ffb3501 1788 def_bool y
95ffa243
YL
1789 prompt "MTRR cleanup support"
1790 depends on MTRR
a7f7f624 1791 help
aba3728c
TG
1792 Convert MTRR layout from continuous to discrete, so X drivers can
1793 add writeback entries.
95ffa243 1794
aba3728c 1795 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1796 The largest mtrr entry size for a continuous block can be set with
aba3728c 1797 mtrr_chunk_size.
95ffa243 1798
2ffb3501 1799 If unsure, say Y.
95ffa243
YL
1800
1801config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1802 int "MTRR cleanup enable value (0-1)"
1803 range 0 1
1804 default "0"
95ffa243 1805 depends on MTRR_SANITIZER
a7f7f624 1806 help
f5098d62 1807 Enable mtrr cleanup default value
95ffa243 1808
12031a62
YL
1809config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1810 int "MTRR cleanup spare reg num (0-7)"
1811 range 0 7
1812 default "1"
1813 depends on MTRR_SANITIZER
a7f7f624 1814 help
12031a62 1815 mtrr cleanup spare entries default, it can be changed via
aba3728c 1816 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1817
2e5d9c85 1818config X86_PAT
6fc108a0 1819 def_bool y
6a108a14 1820 prompt "x86 PAT support" if EXPERT
2a8a2719 1821 depends on MTRR
a7f7f624 1822 help
2e5d9c85 1823 Use PAT attributes to setup page level cache control.
042b78e4 1824
2e5d9c85 1825 PATs are the modern equivalents of MTRRs and are much more
1826 flexible than MTRRs.
1827
1828 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1829 spontaneous reboots) or a non-working video driver.
2e5d9c85 1830
1831 If unsure, say Y.
1832
46cf98cd
VP
1833config ARCH_USES_PG_UNCACHED
1834 def_bool y
1835 depends on X86_PAT
1836
628c6246
PA
1837config ARCH_RANDOM
1838 def_bool y
1839 prompt "x86 architectural random number generator" if EXPERT
a7f7f624 1840 help
628c6246
PA
1841 Enable the x86 architectural RDRAND instruction
1842 (Intel Bull Mountain technology) to generate random numbers.
1843 If supported, this is a high bandwidth, cryptographically
1844 secure hardware random number generator.
1845
51ae4a2d
PA
1846config X86_SMAP
1847 def_bool y
1848 prompt "Supervisor Mode Access Prevention" if EXPERT
a7f7f624 1849 help
51ae4a2d
PA
1850 Supervisor Mode Access Prevention (SMAP) is a security
1851 feature in newer Intel processors. There is a small
1852 performance cost if this enabled and turned on; there is
1853 also a small increase in the kernel size if this is enabled.
1854
1855 If unsure, say Y.
1856
b971880f 1857config X86_UMIP
796ebc81 1858 def_bool y
b971880f 1859 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1860 help
b971880f
BM
1861 User Mode Instruction Prevention (UMIP) is a security feature in
1862 some x86 processors. If enabled, a general protection fault is
1863 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1864 executed in user mode. These instructions unnecessarily expose
1865 information about the hardware state.
796ebc81
RN
1866
1867 The vast majority of applications do not use these instructions.
1868 For the very few that do, software emulation is provided in
1869 specific cases in protected and virtual-8086 modes. Emulated
1870 results are dummy.
aa35f896 1871
35e97790 1872config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1873 prompt "Memory Protection Keys"
35e97790 1874 def_bool y
284244a9 1875 # Note: only available in 64-bit mode
38f3e775 1876 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1877 select ARCH_USES_HIGH_VMA_FLAGS
1878 select ARCH_HAS_PKEYS
a7f7f624 1879 help
284244a9
DH
1880 Memory Protection Keys provides a mechanism for enforcing
1881 page-based protections, but without requiring modification of the
1882 page tables when an application changes protection domains.
1883
1eecbcdc 1884 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1885
1886 If unsure, say y.
35e97790 1887
db616173
MH
1888choice
1889 prompt "TSX enable mode"
1890 depends on CPU_SUP_INTEL
1891 default X86_INTEL_TSX_MODE_OFF
1892 help
1893 Intel's TSX (Transactional Synchronization Extensions) feature
1894 allows to optimize locking protocols through lock elision which
1895 can lead to a noticeable performance boost.
1896
1897 On the other hand it has been shown that TSX can be exploited
1898 to form side channel attacks (e.g. TAA) and chances are there
1899 will be more of those attacks discovered in the future.
1900
1901 Therefore TSX is not enabled by default (aka tsx=off). An admin
1902 might override this decision by tsx=on the command line parameter.
1903 Even with TSX enabled, the kernel will attempt to enable the best
1904 possible TAA mitigation setting depending on the microcode available
1905 for the particular machine.
1906
1907 This option allows to set the default tsx mode between tsx=on, =off
1908 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1909 details.
1910
1911 Say off if not sure, auto if TSX is in use but it should be used on safe
1912 platforms or on if TSX is in use and the security aspect of tsx is not
1913 relevant.
1914
1915config X86_INTEL_TSX_MODE_OFF
1916 bool "off"
1917 help
1918 TSX is disabled if possible - equals to tsx=off command line parameter.
1919
1920config X86_INTEL_TSX_MODE_ON
1921 bool "on"
1922 help
1923 TSX is always enabled on TSX capable HW - equals the tsx=on command
1924 line parameter.
1925
1926config X86_INTEL_TSX_MODE_AUTO
1927 bool "auto"
1928 help
1929 TSX is enabled on TSX capable HW that is believed to be safe against
1930 side channel attacks- equals the tsx=auto command line parameter.
1931endchoice
1932
506f1d07 1933config EFI
9ba16087 1934 bool "EFI runtime service support"
5b83683f 1935 depends on ACPI
f6ce5002 1936 select UCS2_STRING
022ee6c5 1937 select EFI_RUNTIME_WRAPPERS
a7f7f624 1938 help
8f9ca475
IM
1939 This enables the kernel to use EFI runtime services that are
1940 available (such as the EFI variable services).
506f1d07 1941
8f9ca475
IM
1942 This option is only useful on systems that have EFI firmware.
1943 In addition, you should use the latest ELILO loader available
1944 at <http://elilo.sourceforge.net> in order to take advantage
1945 of EFI runtime services. However, even with this option, the
1946 resultant kernel should continue to boot on existing non-EFI
1947 platforms.
506f1d07 1948
291f3632 1949config EFI_STUB
8f24f8c2
AB
1950 bool "EFI stub support"
1951 depends on EFI && !X86_USE_3DNOW
1952 depends on $(cc-option,-mabi=ms) || X86_32
1953 select RELOCATABLE
a7f7f624 1954 help
8f24f8c2 1955 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
1956 by EFI firmware without the use of a bootloader.
1957
4f4cfa6c 1958 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1959
7d453eee
MF
1960config EFI_MIXED
1961 bool "EFI mixed-mode support"
1962 depends on EFI_STUB && X86_64
a7f7f624 1963 help
7d453eee
MF
1964 Enabling this feature allows a 64-bit kernel to be booted
1965 on a 32-bit firmware, provided that your CPU supports 64-bit
1966 mode.
1967
1968 Note that it is not possible to boot a mixed-mode enabled
1969 kernel via the EFI boot stub - a bootloader that supports
1970 the EFI handover protocol must be used.
1971
1972 If unsure, say N.
1973
8636a1f9 1974source "kernel/Kconfig.hz"
506f1d07
SR
1975
1976config KEXEC
1977 bool "kexec system call"
2965faa5 1978 select KEXEC_CORE
a7f7f624 1979 help
506f1d07
SR
1980 kexec is a system call that implements the ability to shutdown your
1981 current kernel, and to start another kernel. It is like a reboot
1982 but it is independent of the system firmware. And like a reboot
1983 you can start any kernel with it, not just Linux.
1984
1985 The name comes from the similarity to the exec system call.
1986
1987 It is an ongoing process to be certain the hardware in a machine
1988 is properly shutdown, so do not be surprised if this code does not
bf220695
GU
1989 initially work for you. As of this writing the exact hardware
1990 interface is strongly in flux, so no good recommendation can be
1991 made.
506f1d07 1992
74ca317c
VG
1993config KEXEC_FILE
1994 bool "kexec file based system call"
2965faa5 1995 select KEXEC_CORE
74ca317c 1996 select BUILD_BIN2C
74ca317c
VG
1997 depends on X86_64
1998 depends on CRYPTO=y
1999 depends on CRYPTO_SHA256=y
a7f7f624 2000 help
74ca317c
VG
2001 This is new version of kexec system call. This system call is
2002 file based and takes file descriptors as system call argument
2003 for kernel and initramfs as opposed to list of segments as
2004 accepted by previous system call.
2005
b799a09f
AT
2006config ARCH_HAS_KEXEC_PURGATORY
2007 def_bool KEXEC_FILE
2008
99d5cadf 2009config KEXEC_SIG
8e7d8381 2010 bool "Verify kernel signature during kexec_file_load() syscall"
74ca317c 2011 depends on KEXEC_FILE
a7f7f624 2012 help
d8eb8940 2013
99d5cadf
JB
2014 This option makes the kexec_file_load() syscall check for a valid
2015 signature of the kernel image. The image can still be loaded without
2016 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2017 there's a signature that we can check, then it must be valid.
2018
2019 In addition to this option, you need to enable signature
d8eb8940
BP
2020 verification for the corresponding kernel image type being
2021 loaded in order for this to work.
8e7d8381 2022
99d5cadf
JB
2023config KEXEC_SIG_FORCE
2024 bool "Require a valid signature in kexec_file_load() syscall"
2025 depends on KEXEC_SIG
a7f7f624 2026 help
99d5cadf
JB
2027 This option makes kernel signature verification mandatory for
2028 the kexec_file_load() syscall.
2029
8e7d8381
VG
2030config KEXEC_BZIMAGE_VERIFY_SIG
2031 bool "Enable bzImage signature verification support"
99d5cadf 2032 depends on KEXEC_SIG
8e7d8381
VG
2033 depends on SIGNED_PE_FILE_VERIFICATION
2034 select SYSTEM_TRUSTED_KEYRING
a7f7f624 2035 help
8e7d8381
VG
2036 Enable bzImage signature verification support.
2037
506f1d07 2038config CRASH_DUMP
04b69447 2039 bool "kernel crash dumps"
506f1d07 2040 depends on X86_64 || (X86_32 && HIGHMEM)
a7f7f624 2041 help
506f1d07
SR
2042 Generate crash dump after being started by kexec.
2043 This should be normally only set in special crash dump kernels
2044 which are loaded in the main kernel with kexec-tools into
2045 a specially reserved region and then later executed after
2046 a crash by kdump/kexec. The crash dump kernel must be compiled
2047 to a memory address not used by the main kernel or BIOS using
2048 PHYSICAL_START, or it must be built as a relocatable image
2049 (CONFIG_RELOCATABLE=y).
330d4810 2050 For more details see Documentation/admin-guide/kdump/kdump.rst
506f1d07 2051
3ab83521 2052config KEXEC_JUMP
6ea30386 2053 bool "kexec jump"
fee7b0d8 2054 depends on KEXEC && HIBERNATION
a7f7f624 2055 help
89081d17
HY
2056 Jump between original kernel and kexeced kernel and invoke
2057 code in physical address mode via KEXEC
3ab83521 2058
506f1d07 2059config PHYSICAL_START
6a108a14 2060 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2061 default "0x1000000"
a7f7f624 2062 help
506f1d07
SR
2063 This gives the physical address where the kernel is loaded.
2064
2065 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2066 bzImage will decompress itself to above physical address and
2067 run from there. Otherwise, bzImage will run from the address where
2068 it has been loaded by the boot loader and will ignore above physical
2069 address.
2070
2071 In normal kdump cases one does not have to set/change this option
2072 as now bzImage can be compiled as a completely relocatable image
2073 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2074 address. This option is mainly useful for the folks who don't want
2075 to use a bzImage for capturing the crash dump and want to use a
2076 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2077 to be specifically compiled to run from a specific memory area
2078 (normally a reserved region) and this option comes handy.
2079
ceefccc9
PA
2080 So if you are using bzImage for capturing the crash dump,
2081 leave the value here unchanged to 0x1000000 and set
2082 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2083 for capturing the crash dump change this value to start of
2084 the reserved region. In other words, it can be set based on
2085 the "X" value as specified in the "crashkernel=YM@XM"
2086 command line boot parameter passed to the panic-ed
330d4810 2087 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2088 for more details about crash dumps.
506f1d07
SR
2089
2090 Usage of bzImage for capturing the crash dump is recommended as
2091 one does not have to build two kernels. Same kernel can be used
2092 as production kernel and capture kernel. Above option should have
2093 gone away after relocatable bzImage support is introduced. But it
2094 is present because there are users out there who continue to use
2095 vmlinux for dump capture. This option should go away down the
2096 line.
2097
2098 Don't change this unless you know what you are doing.
2099
2100config RELOCATABLE
26717808
PA
2101 bool "Build a relocatable kernel"
2102 default y
a7f7f624 2103 help
506f1d07
SR
2104 This builds a kernel image that retains relocation information
2105 so it can be loaded someplace besides the default 1MB.
2106 The relocations tend to make the kernel binary about 10% larger,
2107 but are discarded at runtime.
2108
2109 One use is for the kexec on panic case where the recovery kernel
2110 must live at a different physical address than the primary
2111 kernel.
2112
2113 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2114 it has been loaded at and the compile time physical address
8ab3820f 2115 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2116
8ab3820f 2117config RANDOMIZE_BASE
e8581e3d 2118 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2119 depends on RELOCATABLE
6807c846 2120 default y
a7f7f624 2121 help
e8581e3d
BH
2122 In support of Kernel Address Space Layout Randomization (KASLR),
2123 this randomizes the physical address at which the kernel image
2124 is decompressed and the virtual address where the kernel
2125 image is mapped, as a security feature that deters exploit
2126 attempts relying on knowledge of the location of kernel
2127 code internals.
2128
ed9f007e
KC
2129 On 64-bit, the kernel physical and virtual addresses are
2130 randomized separately. The physical address will be anywhere
2131 between 16MB and the top of physical memory (up to 64TB). The
2132 virtual address will be randomized from 16MB up to 1GB (9 bits
2133 of entropy). Note that this also reduces the memory space
2134 available to kernel modules from 1.5GB to 1GB.
2135
2136 On 32-bit, the kernel physical and virtual addresses are
2137 randomized together. They will be randomized from 16MB up to
2138 512MB (8 bits of entropy).
e8581e3d
BH
2139
2140 Entropy is generated using the RDRAND instruction if it is
2141 supported. If RDTSC is supported, its value is mixed into
2142 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2143 supported, then entropy is read from the i8254 timer. The
2144 usable entropy is limited by the kernel being built using
2145 2GB addressing, and that PHYSICAL_ALIGN must be at a
2146 minimum of 2MB. As a result, only 10 bits of entropy are
2147 theoretically possible, but the implementations are further
2148 limited due to memory layouts.
e8581e3d 2149
6807c846 2150 If unsure, say Y.
8ab3820f
KC
2151
2152# Relocation on x86 needs some additional build support
845adf72
PA
2153config X86_NEED_RELOCS
2154 def_bool y
8ab3820f 2155 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2156
506f1d07 2157config PHYSICAL_ALIGN
a0215061 2158 hex "Alignment value to which kernel should be aligned"
8ab3820f 2159 default "0x200000"
a0215061
KC
2160 range 0x2000 0x1000000 if X86_32
2161 range 0x200000 0x1000000 if X86_64
a7f7f624 2162 help
506f1d07
SR
2163 This value puts the alignment restrictions on physical address
2164 where kernel is loaded and run from. Kernel is compiled for an
2165 address which meets above alignment restriction.
2166
2167 If bootloader loads the kernel at a non-aligned address and
2168 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2169 address aligned to above value and run from there.
2170
2171 If bootloader loads the kernel at a non-aligned address and
2172 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2173 load address and decompress itself to the address it has been
2174 compiled for and run from there. The address for which kernel is
2175 compiled already meets above alignment restrictions. Hence the
2176 end result is that kernel runs from a physical address meeting
2177 above alignment restrictions.
2178
a0215061
KC
2179 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2180 this value must be a multiple of 0x200000.
2181
506f1d07
SR
2182 Don't change this unless you know what you are doing.
2183
eedb92ab
KS
2184config DYNAMIC_MEMORY_LAYOUT
2185 bool
a7f7f624 2186 help
eedb92ab
KS
2187 This option makes base addresses of vmalloc and vmemmap as well as
2188 __PAGE_OFFSET movable during boot.
2189
0483e1fa
TG
2190config RANDOMIZE_MEMORY
2191 bool "Randomize the kernel memory sections"
2192 depends on X86_64
2193 depends on RANDOMIZE_BASE
eedb92ab 2194 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2195 default RANDOMIZE_BASE
a7f7f624 2196 help
0483e1fa
TG
2197 Randomizes the base virtual address of kernel memory sections
2198 (physical memory mapping, vmalloc & vmemmap). This security feature
2199 makes exploits relying on predictable memory locations less reliable.
2200
2201 The order of allocations remains unchanged. Entropy is generated in
2202 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2203 configuration have in average 30,000 different possible virtual
2204 addresses for each memory section.
2205
6807c846 2206 If unsure, say Y.
0483e1fa 2207
90397a41
TG
2208config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2209 hex "Physical memory mapping padding" if EXPERT
2210 depends on RANDOMIZE_MEMORY
2211 default "0xa" if MEMORY_HOTPLUG
2212 default "0x0"
2213 range 0x1 0x40 if MEMORY_HOTPLUG
2214 range 0x0 0x40
a7f7f624 2215 help
90397a41
TG
2216 Define the padding in terabytes added to the existing physical
2217 memory size during kernel memory randomization. It is useful
2218 for memory hotplug support but reduces the entropy available for
2219 address randomization.
2220
2221 If unsure, leave at the default value.
2222
506f1d07 2223config HOTPLUG_CPU
bebd024e 2224 def_bool y
40b31360 2225 depends on SMP
506f1d07 2226
80aa1dff
FY
2227config BOOTPARAM_HOTPLUG_CPU0
2228 bool "Set default setting of cpu0_hotpluggable"
2c922cd0 2229 depends on HOTPLUG_CPU
a7f7f624 2230 help
80aa1dff
FY
2231 Set whether default state of cpu0_hotpluggable is on or off.
2232
2233 Say Y here to enable CPU0 hotplug by default. If this switch
2234 is turned on, there is no need to give cpu0_hotplug kernel
2235 parameter and the CPU0 hotplug feature is enabled by default.
2236
2237 Please note: there are two known CPU0 dependencies if you want
2238 to enable the CPU0 hotplug feature either by this switch or by
2239 cpu0_hotplug kernel parameter.
2240
2241 First, resume from hibernate or suspend always starts from CPU0.
2242 So hibernate and suspend are prevented if CPU0 is offline.
2243
2244 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2245 offline if any interrupt can not migrate out of CPU0. There may
2246 be other CPU0 dependencies.
2247
2248 Please make sure the dependencies are under your control before
2249 you enable this feature.
2250
2251 Say N if you don't want to enable CPU0 hotplug feature by default.
2252 You still can enable the CPU0 hotplug feature at boot by kernel
2253 parameter cpu0_hotplug.
2254
a71c8bc5
FY
2255config DEBUG_HOTPLUG_CPU0
2256 def_bool n
2257 prompt "Debug CPU0 hotplug"
2c922cd0 2258 depends on HOTPLUG_CPU
a7f7f624 2259 help
a71c8bc5
FY
2260 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2261 soon as possible and boots up userspace with CPU0 offlined. User
2262 can online CPU0 back after boot time.
2263
2264 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2265 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2266 compilation or giving cpu0_hotplug kernel parameter at boot.
2267
2268 If unsure, say N.
2269
506f1d07 2270config COMPAT_VDSO
b0b49f26
AL
2271 def_bool n
2272 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2273 depends on COMPAT_32
a7f7f624 2274 help
b0b49f26
AL
2275 Certain buggy versions of glibc will crash if they are
2276 presented with a 32-bit vDSO that is not mapped at the address
2277 indicated in its segment table.
e84446de 2278
b0b49f26
AL
2279 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2280 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2281 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2282 the only released version with the bug, but OpenSUSE 9
2283 contains a buggy "glibc 2.3.2".
506f1d07 2284
b0b49f26
AL
2285 The symptom of the bug is that everything crashes on startup, saying:
2286 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2287
2288 Saying Y here changes the default value of the vdso32 boot
2289 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2290 This works around the glibc bug but hurts performance.
2291
2292 If unsure, say N: if you are compiling your own kernel, you
2293 are unlikely to be using a buggy version of glibc.
506f1d07 2294
3dc33bd3
KC
2295choice
2296 prompt "vsyscall table for legacy applications"
2297 depends on X86_64
625b7b7f 2298 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2299 help
2300 Legacy user code that does not know how to find the vDSO expects
2301 to be able to issue three syscalls by calling fixed addresses in
2302 kernel space. Since this location is not randomized with ASLR,
2303 it can be used to assist security vulnerability exploitation.
2304
2305 This setting can be changed at boot time via the kernel command
bd49e16e 2306 line parameter vsyscall=[emulate|xonly|none].
3dc33bd3
KC
2307
2308 On a system with recent enough glibc (2.14 or newer) and no
2309 static binaries, you can say None without a performance penalty
2310 to improve security.
2311
bd49e16e 2312 If unsure, select "Emulate execution only".
3dc33bd3 2313
3dc33bd3 2314 config LEGACY_VSYSCALL_EMULATE
bd49e16e 2315 bool "Full emulation"
3dc33bd3 2316 help
bd49e16e
AL
2317 The kernel traps and emulates calls into the fixed vsyscall
2318 address mapping. This makes the mapping non-executable, but
2319 it still contains readable known contents, which could be
2320 used in certain rare security vulnerability exploits. This
2321 configuration is recommended when using legacy userspace
2322 that still uses vsyscalls along with legacy binary
2323 instrumentation tools that require code to be readable.
2324
2325 An example of this type of legacy userspace is running
2326 Pin on an old binary that still uses vsyscalls.
2327
2328 config LEGACY_VSYSCALL_XONLY
2329 bool "Emulate execution only"
2330 help
2331 The kernel traps and emulates calls into the fixed vsyscall
2332 address mapping and does not allow reads. This
2333 configuration is recommended when userspace might use the
2334 legacy vsyscall area but support for legacy binary
2335 instrumentation of legacy code is not needed. It mitigates
2336 certain uses of the vsyscall area as an ASLR-bypassing
2337 buffer.
3dc33bd3
KC
2338
2339 config LEGACY_VSYSCALL_NONE
2340 bool "None"
2341 help
2342 There will be no vsyscall mapping at all. This will
2343 eliminate any risk of ASLR bypass due to the vsyscall
2344 fixed address mapping. Attempts to use the vsyscalls
2345 will be reported to dmesg, so that either old or
2346 malicious userspace programs can be identified.
2347
2348endchoice
2349
516cbf37
TB
2350config CMDLINE_BOOL
2351 bool "Built-in kernel command line"
a7f7f624 2352 help
516cbf37
TB
2353 Allow for specifying boot arguments to the kernel at
2354 build time. On some systems (e.g. embedded ones), it is
2355 necessary or convenient to provide some or all of the
2356 kernel boot arguments with the kernel itself (that is,
2357 to not rely on the boot loader to provide them.)
2358
2359 To compile command line arguments into the kernel,
2360 set this option to 'Y', then fill in the
69711ca1 2361 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2362
2363 Systems with fully functional boot loaders (i.e. non-embedded)
2364 should leave this option set to 'N'.
2365
2366config CMDLINE
2367 string "Built-in kernel command string"
2368 depends on CMDLINE_BOOL
2369 default ""
a7f7f624 2370 help
516cbf37
TB
2371 Enter arguments here that should be compiled into the kernel
2372 image and used at boot time. If the boot loader provides a
2373 command line at boot time, it is appended to this string to
2374 form the full kernel command line, when the system boots.
2375
2376 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2377 change this behavior.
2378
2379 In most cases, the command line (whether built-in or provided
2380 by the boot loader) should specify the device for the root
2381 file system.
2382
2383config CMDLINE_OVERRIDE
2384 bool "Built-in command line overrides boot loader arguments"
645e6466 2385 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2386 help
516cbf37
TB
2387 Set this option to 'Y' to have the kernel ignore the boot loader
2388 command line, and use ONLY the built-in command line.
2389
2390 This is used to work around broken boot loaders. This should
2391 be set to 'N' under normal conditions.
2392
a5b9e5a2
AL
2393config MODIFY_LDT_SYSCALL
2394 bool "Enable the LDT (local descriptor table)" if EXPERT
2395 default y
a7f7f624 2396 help
a5b9e5a2
AL
2397 Linux can allow user programs to install a per-process x86
2398 Local Descriptor Table (LDT) using the modify_ldt(2) system
2399 call. This is required to run 16-bit or segmented code such as
2400 DOSEMU or some Wine programs. It is also used by some very old
2401 threading libraries.
2402
2403 Enabling this feature adds a small amount of overhead to
2404 context switches and increases the low-level kernel attack
2405 surface. Disabling it removes the modify_ldt(2) system call.
2406
2407 Saying 'N' here may make sense for embedded or server kernels.
2408
b700e7f0
SJ
2409source "kernel/livepatch/Kconfig"
2410
506f1d07
SR
2411endmenu
2412
3072e413
MH
2413config ARCH_HAS_ADD_PAGES
2414 def_bool y
2415 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2416
506f1d07
SR
2417config ARCH_ENABLE_MEMORY_HOTPLUG
2418 def_bool y
2419 depends on X86_64 || (X86_32 && HIGHMEM)
2420
35551053
GH
2421config ARCH_ENABLE_MEMORY_HOTREMOVE
2422 def_bool y
2423 depends on MEMORY_HOTPLUG
2424
e534c7c5 2425config USE_PERCPU_NUMA_NODE_ID
645a7919 2426 def_bool y
e534c7c5
LS
2427 depends on NUMA
2428
9491846f
KS
2429config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2430 def_bool y
2431 depends on X86_64 || X86_PAE
2432
c177c81e
NH
2433config ARCH_ENABLE_HUGEPAGE_MIGRATION
2434 def_bool y
2435 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2436
9c670ea3
NH
2437config ARCH_ENABLE_THP_MIGRATION
2438 def_bool y
2439 depends on X86_64 && TRANSPARENT_HUGEPAGE
2440
da85f865 2441menu "Power management and ACPI options"
e279b6c1
SR
2442
2443config ARCH_HIBERNATION_HEADER
3c2362e6 2444 def_bool y
44556530 2445 depends on HIBERNATION
e279b6c1
SR
2446
2447source "kernel/power/Kconfig"
2448
2449source "drivers/acpi/Kconfig"
2450
efafc8b2
FT
2451source "drivers/sfi/Kconfig"
2452
a6b68076 2453config X86_APM_BOOT
6fc108a0 2454 def_bool y
282e5aab 2455 depends on APM
a6b68076 2456
e279b6c1
SR
2457menuconfig APM
2458 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2459 depends on X86_32 && PM_SLEEP
a7f7f624 2460 help
e279b6c1
SR
2461 APM is a BIOS specification for saving power using several different
2462 techniques. This is mostly useful for battery powered laptops with
2463 APM compliant BIOSes. If you say Y here, the system time will be
2464 reset after a RESUME operation, the /proc/apm device will provide
2465 battery status information, and user-space programs will receive
2466 notification of APM "events" (e.g. battery status change).
2467
2468 If you select "Y" here, you can disable actual use of the APM
2469 BIOS by passing the "apm=off" option to the kernel at boot time.
2470
2471 Note that the APM support is almost completely disabled for
2472 machines with more than one CPU.
2473
2474 In order to use APM, you will need supporting software. For location
151f4e2b 2475 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2476 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2477 <http://www.tldp.org/docs.html#howto>.
2478
2479 This driver does not spin down disk drives (see the hdparm(8)
2480 manpage ("man 8 hdparm") for that), and it doesn't turn off
2481 VESA-compliant "green" monitors.
2482
2483 This driver does not support the TI 4000M TravelMate and the ACER
2484 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2485 desktop machines also don't have compliant BIOSes, and this driver
2486 may cause those machines to panic during the boot phase.
2487
2488 Generally, if you don't have a battery in your machine, there isn't
2489 much point in using this driver and you should say N. If you get
2490 random kernel OOPSes or reboots that don't seem to be related to
2491 anything, try disabling/enabling this option (or disabling/enabling
2492 APM in your BIOS).
2493
2494 Some other things you should try when experiencing seemingly random,
2495 "weird" problems:
2496
2497 1) make sure that you have enough swap space and that it is
2498 enabled.
2499 2) pass the "no-hlt" option to the kernel
2500 3) switch on floating point emulation in the kernel and pass
2501 the "no387" option to the kernel
2502 4) pass the "floppy=nodma" option to the kernel
2503 5) pass the "mem=4M" option to the kernel (thereby disabling
2504 all but the first 4 MB of RAM)
2505 6) make sure that the CPU is not over clocked.
2506 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2507 8) disable the cache from your BIOS settings
2508 9) install a fan for the video card or exchange video RAM
2509 10) install a better fan for the CPU
2510 11) exchange RAM chips
2511 12) exchange the motherboard.
2512
2513 To compile this driver as a module, choose M here: the
2514 module will be called apm.
2515
2516if APM
2517
2518config APM_IGNORE_USER_SUSPEND
2519 bool "Ignore USER SUSPEND"
a7f7f624 2520 help
e279b6c1
SR
2521 This option will ignore USER SUSPEND requests. On machines with a
2522 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2523 series notebooks, it is necessary to say Y because of a BIOS bug.
2524
2525config APM_DO_ENABLE
2526 bool "Enable PM at boot time"
a7f7f624 2527 help
e279b6c1
SR
2528 Enable APM features at boot time. From page 36 of the APM BIOS
2529 specification: "When disabled, the APM BIOS does not automatically
2530 power manage devices, enter the Standby State, enter the Suspend
2531 State, or take power saving steps in response to CPU Idle calls."
2532 This driver will make CPU Idle calls when Linux is idle (unless this
2533 feature is turned off -- see "Do CPU IDLE calls", below). This
2534 should always save battery power, but more complicated APM features
2535 will be dependent on your BIOS implementation. You may need to turn
2536 this option off if your computer hangs at boot time when using APM
2537 support, or if it beeps continuously instead of suspending. Turn
2538 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2539 T400CDT. This is off by default since most machines do fine without
2540 this feature.
2541
2542config APM_CPU_IDLE
dd8af076 2543 depends on CPU_IDLE
e279b6c1 2544 bool "Make CPU Idle calls when idle"
a7f7f624 2545 help
e279b6c1
SR
2546 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2547 On some machines, this can activate improved power savings, such as
2548 a slowed CPU clock rate, when the machine is idle. These idle calls
2549 are made after the idle loop has run for some length of time (e.g.,
2550 333 mS). On some machines, this will cause a hang at boot time or
2551 whenever the CPU becomes idle. (On machines with more than one CPU,
2552 this option does nothing.)
2553
2554config APM_DISPLAY_BLANK
2555 bool "Enable console blanking using APM"
a7f7f624 2556 help
e279b6c1
SR
2557 Enable console blanking using the APM. Some laptops can use this to
2558 turn off the LCD backlight when the screen blanker of the Linux
2559 virtual console blanks the screen. Note that this is only used by
2560 the virtual console screen blanker, and won't turn off the backlight
2561 when using the X Window system. This also doesn't have anything to
2562 do with your VESA-compliant power-saving monitor. Further, this
2563 option doesn't work for all laptops -- it might not turn off your
2564 backlight at all, or it might print a lot of errors to the console,
2565 especially if you are using gpm.
2566
2567config APM_ALLOW_INTS
2568 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2569 help
e279b6c1
SR
2570 Normally we disable external interrupts while we are making calls to
2571 the APM BIOS as a measure to lessen the effects of a badly behaving
2572 BIOS implementation. The BIOS should reenable interrupts if it
2573 needs to. Unfortunately, some BIOSes do not -- especially those in
2574 many of the newer IBM Thinkpads. If you experience hangs when you
2575 suspend, try setting this to Y. Otherwise, say N.
2576
e279b6c1
SR
2577endif # APM
2578
bb0a56ec 2579source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2580
2581source "drivers/cpuidle/Kconfig"
2582
27471fdb
AH
2583source "drivers/idle/Kconfig"
2584
e279b6c1
SR
2585endmenu
2586
2587
2588menu "Bus options (PCI etc.)"
2589
e279b6c1
SR
2590choice
2591 prompt "PCI access mode"
efefa6f6 2592 depends on X86_32 && PCI
e279b6c1 2593 default PCI_GOANY
a7f7f624 2594 help
e279b6c1
SR
2595 On PCI systems, the BIOS can be used to detect the PCI devices and
2596 determine their configuration. However, some old PCI motherboards
2597 have BIOS bugs and may crash if this is done. Also, some embedded
2598 PCI-based systems don't have any BIOS at all. Linux can also try to
2599 detect the PCI hardware directly without using the BIOS.
2600
2601 With this option, you can specify how Linux should detect the
2602 PCI devices. If you choose "BIOS", the BIOS will be used,
2603 if you choose "Direct", the BIOS won't be used, and if you
2604 choose "MMConfig", then PCI Express MMCONFIG will be used.
2605 If you choose "Any", the kernel will try MMCONFIG, then the
2606 direct access method and falls back to the BIOS if that doesn't
2607 work. If unsure, go with the default, which is "Any".
2608
2609config PCI_GOBIOS
2610 bool "BIOS"
2611
2612config PCI_GOMMCONFIG
2613 bool "MMConfig"
2614
2615config PCI_GODIRECT
2616 bool "Direct"
2617
3ef0e1f8 2618config PCI_GOOLPC
76fb6570 2619 bool "OLPC XO-1"
3ef0e1f8
AS
2620 depends on OLPC
2621
2bdd1b03
AS
2622config PCI_GOANY
2623 bool "Any"
2624
e279b6c1
SR
2625endchoice
2626
2627config PCI_BIOS
3c2362e6 2628 def_bool y
efefa6f6 2629 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2630
2631# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2632config PCI_DIRECT
3c2362e6 2633 def_bool y
0aba496f 2634 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2635
2636config PCI_MMCONFIG
b45c9f36
JK
2637 bool "Support mmconfig PCI config space access" if X86_64
2638 default y
8364e1f8 2639 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
b45c9f36 2640 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2641
3ef0e1f8 2642config PCI_OLPC
2bdd1b03
AS
2643 def_bool y
2644 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2645
b5401a96
AN
2646config PCI_XEN
2647 def_bool y
2648 depends on PCI && XEN
2649 select SWIOTLB_XEN
2650
8364e1f8
JK
2651config MMCONF_FAM10H
2652 def_bool y
2653 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2654
3f6ea84a 2655config PCI_CNB20LE_QUIRK
6a108a14 2656 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2657 depends on PCI
3f6ea84a
IS
2658 help
2659 Read the PCI windows out of the CNB20LE host bridge. This allows
2660 PCI hotplug to work on systems with the CNB20LE chipset which do
2661 not have ACPI.
2662
64a5fed6
BH
2663 There's no public spec for this chipset, and this functionality
2664 is known to be incomplete.
2665
2666 You should say N unless you know you need this.
2667
3a495511 2668config ISA_BUS
17a2a129 2669 bool "ISA bus support on modern systems" if EXPERT
3a495511 2670 help
17a2a129
WBG
2671 Expose ISA bus device drivers and options available for selection and
2672 configuration. Enable this option if your target machine has an ISA
2673 bus. ISA is an older system, displaced by PCI and newer bus
2674 architectures -- if your target machine is modern, it probably does
2675 not have an ISA bus.
3a495511
WBG
2676
2677 If unsure, say N.
2678
1c00f016 2679# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2680config ISA_DMA_API
1c00f016
DR
2681 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2682 default y
2683 help
2684 Enables ISA-style DMA support for devices requiring such controllers.
2685 If unsure, say Y.
e279b6c1 2686
51e68d05
LT
2687if X86_32
2688
e279b6c1
SR
2689config ISA
2690 bool "ISA support"
a7f7f624 2691 help
e279b6c1
SR
2692 Find out whether you have ISA slots on your motherboard. ISA is the
2693 name of a bus system, i.e. the way the CPU talks to the other stuff
2694 inside your box. Other bus systems are PCI, EISA, MicroChannel
2695 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2696 newer boards don't support it. If you have ISA, say Y, otherwise N.
2697
e279b6c1
SR
2698config SCx200
2699 tristate "NatSemi SCx200 support"
a7f7f624 2700 help
e279b6c1
SR
2701 This provides basic support for National Semiconductor's
2702 (now AMD's) Geode processors. The driver probes for the
2703 PCI-IDs of several on-chip devices, so its a good dependency
2704 for other scx200_* drivers.
2705
2706 If compiled as a module, the driver is named scx200.
2707
2708config SCx200HR_TIMER
2709 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2710 depends on SCx200
e279b6c1 2711 default y
a7f7f624 2712 help
e279b6c1
SR
2713 This driver provides a clocksource built upon the on-chip
2714 27MHz high-resolution timer. Its also a workaround for
2715 NSC Geode SC-1100's buggy TSC, which loses time when the
2716 processor goes idle (as is done by the scheduler). The
2717 other workaround is idle=poll boot option.
2718
3ef0e1f8
AS
2719config OLPC
2720 bool "One Laptop Per Child support"
54008979 2721 depends on !X86_PAE
3c554946 2722 select GPIOLIB
dc3119e7 2723 select OF
45bb1674 2724 select OF_PROMTREE
b4e51854 2725 select IRQ_DOMAIN
0c3d931b 2726 select OLPC_EC
a7f7f624 2727 help
3ef0e1f8
AS
2728 Add support for detecting the unique features of the OLPC
2729 XO hardware.
2730
a3128588
DD
2731config OLPC_XO1_PM
2732 bool "OLPC XO-1 Power Management"
fa112cf1 2733 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 2734 help
97c4cb71 2735 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2736
cfee9597
DD
2737config OLPC_XO1_RTC
2738 bool "OLPC XO-1 Real Time Clock"
2739 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 2740 help
cfee9597
DD
2741 Add support for the XO-1 real time clock, which can be used as a
2742 programmable wakeup source.
2743
7feda8e9
DD
2744config OLPC_XO1_SCI
2745 bool "OLPC XO-1 SCI extras"
92e830f2 2746 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2747 depends on INPUT=y
d8d01a63 2748 select POWER_SUPPLY
a7f7f624 2749 help
7feda8e9 2750 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2751 - EC-driven system wakeups
7feda8e9 2752 - Power button
7bc74b3d 2753 - Ebook switch
2cf2baea 2754 - Lid switch
e1040ac6
DD
2755 - AC adapter status updates
2756 - Battery status updates
7feda8e9 2757
a0f30f59
DD
2758config OLPC_XO15_SCI
2759 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2760 depends on OLPC && ACPI
2761 select POWER_SUPPLY
a7f7f624 2762 help
a0f30f59
DD
2763 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2764 - EC-driven system wakeups
2765 - AC adapter status updates
2766 - Battery status updates
bf1ebf00 2767
d4f3e350
EW
2768config ALIX
2769 bool "PCEngines ALIX System Support (LED setup)"
2770 select GPIOLIB
a7f7f624 2771 help
d4f3e350
EW
2772 This option enables system support for the PCEngines ALIX.
2773 At present this just sets up LEDs for GPIO control on
2774 ALIX2/3/6 boards. However, other system specific setup should
2775 get added here.
2776
2777 Note: You must still enable the drivers for GPIO and LED support
2778 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2779
2780 Note: You have to set alix.force=1 for boards with Award BIOS.
2781
da4e3302
PP
2782config NET5501
2783 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2784 select GPIOLIB
a7f7f624 2785 help
da4e3302
PP
2786 This option enables system support for the Soekris Engineering net5501.
2787
3197059a
PP
2788config GEOS
2789 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2790 select GPIOLIB
2791 depends on DMI
a7f7f624 2792 help
3197059a
PP
2793 This option enables system support for the Traverse Technologies GEOS.
2794
7d029125
VD
2795config TS5500
2796 bool "Technologic Systems TS-5500 platform support"
2797 depends on MELAN
2798 select CHECK_SIGNATURE
2799 select NEW_LEDS
2800 select LEDS_CLASS
a7f7f624 2801 help
7d029125
VD
2802 This option enables system support for the Technologic Systems TS-5500.
2803
bc0120fd
SR
2804endif # X86_32
2805
23ac4ae8 2806config AMD_NB
e279b6c1 2807 def_bool y
0e152cd7 2808 depends on CPU_SUP_AMD && PCI
e279b6c1 2809
e3263ab3
DR
2810config X86_SYSFB
2811 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2812 help
2813 Firmwares often provide initial graphics framebuffers so the BIOS,
2814 bootloader or kernel can show basic video-output during boot for
2815 user-guidance and debugging. Historically, x86 used the VESA BIOS
2816 Extensions and EFI-framebuffers for this, which are mostly limited
2817 to x86.
2818 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2819 framebuffers so the new generic system-framebuffer drivers can be
2820 used on x86. If the framebuffer is not compatible with the generic
e3a5dc08 2821 modes, it is advertised as fallback platform framebuffer so legacy
e3263ab3
DR
2822 drivers like efifb, vesafb and uvesafb can pick it up.
2823 If this option is not selected, all system framebuffers are always
2824 marked as fallback platform framebuffers as usual.
2825
2826 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2827 not be able to pick up generic system framebuffers if this option
2828 is selected. You are highly encouraged to enable simplefb as
2829 replacement if you select this option. simplefb can correctly deal
2830 with generic system framebuffers. But you should still keep vesafb
2831 and others enabled as fallback if a system framebuffer is
2832 incompatible with simplefb.
2833
2834 If unsure, say Y.
2835
e279b6c1
SR
2836endmenu
2837
2838
1572497c 2839menu "Binary Emulations"
e279b6c1
SR
2840
2841config IA32_EMULATION
2842 bool "IA32 Emulation"
2843 depends on X86_64
39f88911 2844 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2845 select BINFMT_ELF
a97f52e6 2846 select COMPAT_BINFMT_ELF
39f88911 2847 select COMPAT_OLD_SIGACTION
a7f7f624 2848 help
5fd92e65
L
2849 Include code to run legacy 32-bit programs under a
2850 64-bit kernel. You should likely turn this on, unless you're
2851 100% sure that you don't have any 32-bit programs left.
e279b6c1
SR
2852
2853config IA32_AOUT
8f9ca475
IM
2854 tristate "IA32 a.out support"
2855 depends on IA32_EMULATION
eac61655 2856 depends on BROKEN
a7f7f624 2857 help
8f9ca475 2858 Support old a.out binaries in the 32bit emulation.
e279b6c1 2859
0bf62763 2860config X86_X32
6ea30386 2861 bool "x32 ABI for 64-bit mode"
9b54050b 2862 depends on X86_64
a7f7f624 2863 help
5fd92e65
L
2864 Include code to run binaries for the x32 native 32-bit ABI
2865 for 64-bit processors. An x32 process gets access to the
2866 full 64-bit register file and wide data path while leaving
2867 pointers at 32 bits for smaller memory footprint.
2868
2869 You will need a recent binutils (2.22 or later) with
2870 elf32_x86_64 support enabled to compile a kernel with this
2871 option set.
2872
953fee1d
IM
2873config COMPAT_32
2874 def_bool y
2875 depends on IA32_EMULATION || X86_32
2876 select HAVE_UID16
2877 select OLD_SIGSUSPEND3
2878
e279b6c1 2879config COMPAT
3c2362e6 2880 def_bool y
0bf62763 2881 depends on IA32_EMULATION || X86_X32
e279b6c1 2882
3120e25e 2883if COMPAT
e279b6c1 2884config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2885 def_bool y
e279b6c1
SR
2886
2887config SYSVIPC_COMPAT
3c2362e6 2888 def_bool y
3120e25e 2889 depends on SYSVIPC
3120e25e 2890endif
ee009e4a 2891
e279b6c1
SR
2892endmenu
2893
2894
e5beae16
KP
2895config HAVE_ATOMIC_IOMAP
2896 def_bool y
2897 depends on X86_32
2898
e279b6c1
SR
2899source "drivers/firmware/Kconfig"
2900
edf88417 2901source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
2902
2903source "arch/x86/Kconfig.assembler"