x86/math-emu: Check __copy_from_user() result
[linux-block.git] / arch / x86 / Kconfig
CommitLineData
b2441318 1# SPDX-License-Identifier: GPL-2.0
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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"
8f9ca475 6 ---help---
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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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11 def_bool y
12 depends on !64BIT
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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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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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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
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IM
27 select ARCH_SUPPORTS_INT128
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
f8781c4a 33 select ARCH_HAS_SYSCALL_WRAPPER
1032c0ba 34
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SRV
35config FORCE_DYNAMIC_FTRACE
36 def_bool y
37 depends on X86_32
38 depends on FUNCTION_TRACER
39 select DYNAMIC_FTRACE
40 help
41 We keep the static function tracing (!DYNAMIC_FTRACE) around
42 in order to test the non static function tracing in the
43 generic code, as other architectures still use it. But we
44 only need to keep it around for x86_64. No need to keep it
45 for x86_32. For x86_32, force DYNAMIC_FTRACE.
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IM
46#
47# Arch settings
48#
49# ( Note that options that are marked 'if X86_64' could in principle be
50# ported to 32-bit as well. )
51#
8d5fffb9 52config X86
3c2362e6 53 def_bool y
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54 #
55 # Note: keep this list sorted alphabetically
56 #
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57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
942fa985 59 select ARCH_32BIT_OFF_T if X86_32
6471b825 60 select ARCH_CLOCKSOURCE_DATA
2a21ad57 61 select ARCH_CLOCKSOURCE_INIT
c763ea26 62 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
fa5b6ec9 63 select ARCH_HAS_DEBUG_VIRTUAL
21266be9 64 select ARCH_HAS_DEVMEM_IS_ALLOWED
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
5c9a8750 70 select ARCH_HAS_KCOV if X86_64
0c9c1d56 71 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE
c763ea26 73 select ARCH_HAS_PMEM_API if X86_64
17596731 74 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 75 select ARCH_HAS_PTE_SPECIAL
39208aa7 76 select ARCH_HAS_REFCOUNT
0aed55af 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
092b31aa 78 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
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
c6d30853 84 select ARCH_HAS_UBSAN_SANITIZE_ALL
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85 select ARCH_HAVE_NMI_SAFE_CMPXCHG
86 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 87 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 88 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 89 select ARCH_STACKWALK
2c870e61 90 select ARCH_SUPPORTS_ACPI
6471b825 91 select ARCH_SUPPORTS_ATOMIC_RMW
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92 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
93 select ARCH_USE_BUILTIN_BSWAP
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94 select ARCH_USE_QUEUED_RWLOCKS
95 select ARCH_USE_QUEUED_SPINLOCKS
ce4a4e56 96 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
c763ea26 97 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
3876d4a3 98 select ARCH_WANT_HUGE_PMD_SHARE
38d8b4e6 99 select ARCH_WANTS_THP_SWAP if X86_64
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100 select BUILDTIME_EXTABLE_SORT
101 select CLKEVT_I8253
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102 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
103 select CLOCKSOURCE_WATCHDOG
6471b825 104 select DCACHE_WORD_ACCESS
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LT
105 select EDAC_ATOMIC_SCRUB
106 select EDAC_SUPPORT
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IM
107 select GENERIC_CLOCKEVENTS
108 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
109 select GENERIC_CLOCKEVENTS_MIN_ADJUST
110 select GENERIC_CMOS_UPDATE
111 select GENERIC_CPU_AUTOPROBE
61dc0f55 112 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 113 select GENERIC_EARLY_IOREMAP
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114 select GENERIC_FIND_FIRST_BIT
115 select GENERIC_IOMAP
c7d6c9dd 116 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 117 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 118 select GENERIC_IRQ_MIGRATION if SMP
6471b825 119 select GENERIC_IRQ_PROBE
c201c917 120 select GENERIC_IRQ_RESERVATION_MODE
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IM
121 select GENERIC_IRQ_SHOW
122 select GENERIC_PENDING_IRQ if SMP
123 select GENERIC_SMP_IDLE_THREAD
124 select GENERIC_STRNCPY_FROM_USER
125 select GENERIC_STRNLEN_USER
126 select GENERIC_TIME_VSYSCALL
7ac87074 127 select GENERIC_GETTIMEOFDAY
39656e83 128 select GUP_GET_PTE_LOW_HIGH if X86_PAE
7edaeb68 129 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
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130 select HAVE_ACPI_APEI if ACPI
131 select HAVE_ACPI_APEI_NMI if ACPI
132 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
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133 select HAVE_ARCH_AUDITSYSCALL
134 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
135 select HAVE_ARCH_JUMP_LABEL
b34006c4 136 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 137 select HAVE_ARCH_KASAN if X86_64
6471b825 138 select HAVE_ARCH_KGDB
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DC
139 select HAVE_ARCH_MMAP_RND_BITS if MMU
140 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 141 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 142 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 143 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 144 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 145 select HAVE_ARCH_STACKLEAK
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146 select HAVE_ARCH_TRACEHOOK
147 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 148 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
e37e43a4 149 select HAVE_ARCH_VMAP_STACK if X86_64
c763ea26 150 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 151 select HAVE_ASM_MODVERSIONS
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IM
152 select HAVE_CMPXCHG_DOUBLE
153 select HAVE_CMPXCHG_LOCAL
154 select HAVE_CONTEXT_TRACKING if X86_64
c1bd55f9 155 select HAVE_COPY_THREAD_TLS
cf4db259 156 select HAVE_C_RECORDMCOUNT
6471b825 157 select HAVE_DEBUG_KMEMLEAK
6471b825 158 select HAVE_DMA_CONTIGUOUS
677aa9f7 159 select HAVE_DYNAMIC_FTRACE
06aeaaea 160 select HAVE_DYNAMIC_FTRACE_WITH_REGS
03f5781b 161 select HAVE_EBPF_JIT
58340a07 162 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 163 select HAVE_EISA
5f56a5df 164 select HAVE_EXIT_THREAD
67a929e0 165 select HAVE_FAST_GUP
644e0e8d 166 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 167 select HAVE_FTRACE_MCOUNT_RECORD
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168 select HAVE_FUNCTION_GRAPH_TRACER
169 select HAVE_FUNCTION_TRACER
6b90bd4b 170 select HAVE_GCC_PLUGINS
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171 select HAVE_HW_BREAKPOINT
172 select HAVE_IDE
173 select HAVE_IOREMAP_PROT
174 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
175 select HAVE_IRQ_TIME_ACCOUNTING
2e9f3bdd 176 select HAVE_KERNEL_BZIP2
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177 select HAVE_KERNEL_GZIP
178 select HAVE_KERNEL_LZ4
2e9f3bdd 179 select HAVE_KERNEL_LZMA
13510997 180 select HAVE_KERNEL_LZO
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181 select HAVE_KERNEL_XZ
182 select HAVE_KPROBES
183 select HAVE_KPROBES_ON_FTRACE
540adea3 184 select HAVE_FUNCTION_ERROR_INJECTION
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185 select HAVE_KRETPROBES
186 select HAVE_KVM
187 select HAVE_LIVEPATCH if X86_64
6471b825 188 select HAVE_MEMBLOCK_NODE_MAP
0102752e 189 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 190 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 191 select HAVE_MOVE_PMD
42a0bb3f 192 select HAVE_NMI
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IM
193 select HAVE_OPROFILE
194 select HAVE_OPTPROBES
195 select HAVE_PCSPKR_PLATFORM
196 select HAVE_PERF_EVENTS
c01d4323 197 select HAVE_PERF_EVENTS_NMI
92e5aae4 198 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 199 select HAVE_PCI
c5e63197 200 select HAVE_PERF_REGS
c5ebcedb 201 select HAVE_PERF_USER_STACK_DUMP
48a8b97c 202 select HAVE_RCU_TABLE_FREE if PARAVIRT
6471b825 203 select HAVE_REGS_AND_STACK_ACCESS_API
6415b38b 204 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
3c88ee19 205 select HAVE_FUNCTION_ARG_ACCESS_API
d148eac0 206 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
c763ea26 207 select HAVE_STACK_VALIDATION if X86_64
d6761b8f 208 select HAVE_RSEQ
6471b825 209 select HAVE_SYSCALL_TRACEPOINTS
6471b825 210 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 211 select HAVE_USER_RETURN_NOTIFIER
7ac87074 212 select HAVE_GENERIC_VDSO
05736e4a 213 select HOTPLUG_SMT if SMP
c0185808 214 select IRQ_FORCED_THREADING
86596f0a 215 select NEED_SG_DMA_LENGTH
2eac9c2d 216 select PCI_DOMAINS if PCI
625210cf 217 select PCI_LOCKLESS_CONFIG if PCI
6471b825 218 select PERF_EVENTS
3195ef59 219 select RTC_LIB
d6faca40 220 select RTC_MC146818_LIB
6471b825 221 select SPARSE_IRQ
83fe27ea 222 select SRCU
6471b825 223 select SYSCTL_EXCEPTION_TRACE
15f4eae7 224 select THREAD_INFO_IN_TASK
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IM
225 select USER_STACKTRACE_SUPPORT
226 select VIRT_TO_BUS
6471b825 227 select X86_FEATURE_NAMES if PROC_FS
0c608dad 228 select PROC_PID_ARCH_STATUS if PROC_FS
7d8330a5 229
ba7e4d13 230config INSTRUCTION_DECODER
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231 def_bool y
232 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 233
51b26ada
LT
234config OUTPUT_FORMAT
235 string
236 default "elf32-i386" if X86_32
237 default "elf64-x86-64" if X86_64
238
73531905 239config ARCH_DEFCONFIG
b9b39bfb 240 string
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SR
241 default "arch/x86/configs/i386_defconfig" if X86_32
242 default "arch/x86/configs/x86_64_defconfig" if X86_64
b9b39bfb 243
8d5fffb9 244config LOCKDEP_SUPPORT
3c2362e6 245 def_bool y
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SR
246
247config STACKTRACE_SUPPORT
3c2362e6 248 def_bool y
8d5fffb9 249
8d5fffb9 250config MMU
3c2362e6 251 def_bool y
8d5fffb9 252
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DC
253config ARCH_MMAP_RND_BITS_MIN
254 default 28 if 64BIT
255 default 8
256
257config ARCH_MMAP_RND_BITS_MAX
258 default 32 if 64BIT
259 default 16
260
261config ARCH_MMAP_RND_COMPAT_BITS_MIN
262 default 8
263
264config ARCH_MMAP_RND_COMPAT_BITS_MAX
265 default 16
266
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SR
267config SBUS
268 bool
269
270config GENERIC_ISA_DMA
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JB
271 def_bool y
272 depends on ISA_DMA_API
8d5fffb9 273
8d5fffb9 274config GENERIC_BUG
3c2362e6 275 def_bool y
8d5fffb9 276 depends on BUG
b93a531e
JB
277 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
278
279config GENERIC_BUG_RELATIVE_POINTERS
280 bool
8d5fffb9 281
8d5fffb9 282config ARCH_MAY_HAVE_PC_FDC
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283 def_bool y
284 depends on ISA_DMA_API
8d5fffb9 285
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SR
286config GENERIC_CALIBRATE_DELAY
287 def_bool y
288
9a0b8415 289config ARCH_HAS_CPU_RELAX
290 def_bool y
291
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292config ARCH_HAS_CACHE_LINE_SIZE
293 def_bool y
294
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DH
295config ARCH_HAS_FILTER_PGPROT
296 def_bool y
297
dd5af90a 298config HAVE_SETUP_PER_CPU_AREA
89c9c4c5 299 def_bool y
b32ef636 300
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TH
301config NEED_PER_CPU_EMBED_FIRST_CHUNK
302 def_bool y
303
304config NEED_PER_CPU_PAGE_FIRST_CHUNK
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TH
305 def_bool y
306
801e4062
JB
307config ARCH_HIBERNATION_POSSIBLE
308 def_bool y
801e4062 309
f4cb5700
JB
310config ARCH_SUSPEND_POSSIBLE
311 def_bool y
f4cb5700 312
53313b2c
SC
313config ARCH_WANT_GENERAL_HUGETLB
314 def_bool y
315
8d5fffb9 316config ZONE_DMA32
e0fd24a3 317 def_bool y if X86_64
8d5fffb9 318
8d5fffb9 319config AUDIT_ARCH
e0fd24a3 320 def_bool y if X86_64
8d5fffb9 321
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AM
322config ARCH_SUPPORTS_DEBUG_PAGEALLOC
323 def_bool y
324
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325config KASAN_SHADOW_OFFSET
326 hex
327 depends on KASAN
328 default 0xdffffc0000000000
329
69575d38
SW
330config HAVE_INTEL_TXT
331 def_bool y
6ea30386 332 depends on INTEL_IOMMU && ACPI
69575d38 333
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SR
334config X86_32_SMP
335 def_bool y
336 depends on X86_32 && SMP
337
338config X86_64_SMP
339 def_bool y
340 depends on X86_64 && SMP
341
ccbeed3a
TH
342config X86_32_LAZY_GS
343 def_bool y
8458f8c2 344 depends on X86_32 && !STACKPROTECTOR
ccbeed3a 345
2b144498
SD
346config ARCH_SUPPORTS_UPROBES
347 def_bool y
348
d20642f0
RH
349config FIX_EARLYCON_MEM
350 def_bool y
351
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KS
352config DYNAMIC_PHYSICAL_MASK
353 bool
354
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355config PGTABLE_LEVELS
356 int
77ef56e4 357 default 5 if X86_5LEVEL
98233368
KS
358 default 4 if X86_64
359 default 3 if X86_PAE
360 default 2
361
2a61f474
MY
362config CC_HAS_SANE_STACKPROTECTOR
363 bool
364 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
365 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
366 help
367 We have to make sure stack protector is unconditionally disabled if
368 the compiler produces broken code.
369
506f1d07
SR
370menu "Processor type and features"
371
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RD
372config ZONE_DMA
373 bool "DMA memory allocation support" if EXPERT
374 default y
375 help
376 DMA memory allocation support allows devices with less than 32-bit
377 addressing to allocate within the first 16MB of address space.
378 Disable if no such devices will be used.
379
380 If unsure, say Y.
381
506f1d07
SR
382config SMP
383 bool "Symmetric multi-processing support"
384 ---help---
385 This enables support for systems with more than one CPU. If you have
4a474157
RG
386 a system with only one CPU, say N. If you have a system with more
387 than one CPU, say Y.
506f1d07 388
4a474157 389 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
390 machines, but will use only one CPU of a multiprocessor machine. If
391 you say Y here, the kernel will run on many, but not all,
4a474157 392 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
393 will run faster if you say N here.
394
395 Note that if you say Y here and choose architecture "586" or
396 "Pentium" under "Processor family", the kernel will not work on 486
397 architectures. Similarly, multiprocessor kernels for the "PPro"
398 architecture may not work on all Pentium based boards.
399
400 People using multiprocessor machines who say Y here should also say
401 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
402 Management" code will be disabled if you say Y here.
403
cb1aaebe 404 See also <file:Documentation/x86/i386/IO-APIC.rst>,
4f4cfa6c 405 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
406 <http://www.tldp.org/docs.html#howto>.
407
408 If you don't know what to do here, say N.
409
9def39be
JT
410config X86_FEATURE_NAMES
411 bool "Processor feature human-readable names" if EMBEDDED
412 default y
413 ---help---
414 This option compiles in a table of x86 feature bits and corresponding
415 names. This is required to support /proc/cpuinfo and a few kernel
416 messages. You can disable this to save space, at the expense of
417 making those few kernel messages show numeric feature bits instead.
418
419 If in doubt, say Y.
420
06cd9a7d
YL
421config X86_X2APIC
422 bool "Support x2apic"
19e3d60d 423 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
06cd9a7d
YL
424 ---help---
425 This enables x2apic support on CPUs that have this feature.
426
427 This allows 32-bit apic IDs (so it can support very large systems),
428 and accesses the local apic via MSRs not via mmio.
429
06cd9a7d
YL
430 If you don't know what to do here, say N.
431
6695c85b 432config X86_MPPARSE
6e87f9b7 433 bool "Enable MPS table" if ACPI || SFI
7a527688 434 default y
5ab74722 435 depends on X86_LOCAL_APIC
8f9ca475 436 ---help---
6695c85b
YL
437 For old smp systems that do not have proper acpi support. Newer systems
438 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 439
ddd70cf9
JN
440config GOLDFISH
441 def_bool y
442 depends on X86_GOLDFISH
443
76b04384
DW
444config RETPOLINE
445 bool "Avoid speculative indirect branches in kernel"
446 default y
d5028ba8 447 select STACK_VALIDATION if HAVE_STACK_VALIDATION
76b04384
DW
448 help
449 Compile kernel with the retpoline compiler options to guard against
450 kernel-to-user data leaks by avoiding speculative indirect
451 branches. Requires a compiler with -mindirect-branch=thunk-extern
452 support for full protection. The kernel may run slower.
453
e6d42931
JW
454config X86_CPU_RESCTRL
455 bool "x86 CPU resource control support"
6fe07ce3 456 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 457 select KERNFS
78e99b4a 458 help
e6d42931 459 Enable x86 CPU resource control support.
6fe07ce3
BM
460
461 Provide support for the allocation and monitoring of system resources
462 usage by the CPU.
463
464 Intel calls this Intel Resource Director Technology
465 (Intel(R) RDT). More information about RDT can be found in the
466 Intel x86 Architecture Software Developer Manual.
467
468 AMD calls this AMD Platform Quality of Service (AMD QoS).
469 More information about AMD QoS can be found in the AMD64 Technology
470 Platform Quality of Service Extensions manual.
78e99b4a
FY
471
472 Say N if unsure.
473
8425091f 474if X86_32
a0d0bb4d
RD
475config X86_BIGSMP
476 bool "Support for big SMP systems with more than 8 CPUs"
477 depends on SMP
478 ---help---
479 This option is needed for the systems that have more than 8 CPUs
480
c5c606d9
RT
481config X86_EXTENDED_PLATFORM
482 bool "Support for extended (non-PC) x86 platforms"
483 default y
8f9ca475 484 ---help---
06ac8346
IM
485 If you disable this option then the kernel will only support
486 standard PC platforms. (which covers the vast majority of
487 systems out there.)
488
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RT
489 If you enable this option then you'll be able to select support
490 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 491 Goldfish (Android emulator)
8425091f 492 AMD Elan
8425091f
RT
493 RDC R-321x SoC
494 SGI 320/540 (Visual Workstation)
83125a3a 495 STA2X11-based (e.g. Northville)
3f4110a4 496 Moorestown MID devices
06ac8346
IM
497
498 If you have one of these systems, or if you want to build a
499 generic distribution kernel, say Y here - otherwise say N.
8425091f 500endif
06ac8346 501
8425091f
RT
502if X86_64
503config X86_EXTENDED_PLATFORM
504 bool "Support for extended (non-PC) x86 platforms"
505 default y
506 ---help---
507 If you disable this option then the kernel will only support
508 standard PC platforms. (which covers the vast majority of
509 systems out there.)
510
511 If you enable this option then you'll be able to select support
512 for the following (non-PC) 64 bit x86 platforms:
44b111b5 513 Numascale NumaChip
8425091f
RT
514 ScaleMP vSMP
515 SGI Ultraviolet
516
517 If you have one of these systems, or if you want to build a
518 generic distribution kernel, say Y here - otherwise say N.
519endif
c5c606d9
RT
520# This is an alphabetically sorted list of 64 bit extended platforms
521# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
522config X86_NUMACHIP
523 bool "Numascale NumaChip"
524 depends on X86_64
525 depends on X86_EXTENDED_PLATFORM
526 depends on NUMA
527 depends on SMP
528 depends on X86_X2APIC
f9726bfd 529 depends on PCI_MMCONFIG
44b111b5
SP
530 ---help---
531 Adds support for Numascale NumaChip large-SMP systems. Needed to
532 enable more than ~168 cores.
533 If you don't have one of these, you should say N here.
506f1d07 534
c5c606d9
RT
535config X86_VSMP
536 bool "ScaleMP vSMP"
6276a074 537 select HYPERVISOR_GUEST
c5c606d9
RT
538 select PARAVIRT
539 depends on X86_64 && PCI
540 depends on X86_EXTENDED_PLATFORM
ead91d4b 541 depends on SMP
8f9ca475 542 ---help---
c5c606d9
RT
543 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
544 supposed to run on these EM64T-based machines. Only choose this option
545 if you have one of these machines.
5e3a77e9 546
03b48632
NP
547config X86_UV
548 bool "SGI Ultraviolet"
549 depends on X86_64
c5c606d9 550 depends on X86_EXTENDED_PLATFORM
54c28d29 551 depends on NUMA
1ecb4ae5 552 depends on EFI
9d6c26e7 553 depends on X86_X2APIC
1222e564 554 depends on PCI
8f9ca475 555 ---help---
03b48632
NP
556 This option is needed in order to support SGI Ultraviolet systems.
557 If you don't have one of these, you should say N here.
558
c5c606d9
RT
559# Following is an alphabetically sorted list of 32 bit extended platforms
560# Please maintain the alphabetic order if and when there are additions
506f1d07 561
ddd70cf9
JN
562config X86_GOLDFISH
563 bool "Goldfish (Virtual Platform)"
cb7b8023 564 depends on X86_EXTENDED_PLATFORM
ddd70cf9
JN
565 ---help---
566 Enable support for the Goldfish virtual platform used primarily
567 for Android development. Unless you are building for the Android
568 Goldfish emulator say N here.
569
c751e17b
TG
570config X86_INTEL_CE
571 bool "CE4100 TV platform"
572 depends on PCI
573 depends on PCI_GODIRECT
6084a6e2 574 depends on X86_IO_APIC
c751e17b
TG
575 depends on X86_32
576 depends on X86_EXTENDED_PLATFORM
37bc9f50 577 select X86_REBOOTFIXUPS
da6b737b
SAS
578 select OF
579 select OF_EARLY_FLATTREE
c751e17b
TG
580 ---help---
581 Select for the Intel CE media processor (CE4100) SOC.
582 This option compiles in support for the CE4100 SOC for settop
583 boxes and media devices.
584
4cb9b00f 585config X86_INTEL_MID
43605ef1 586 bool "Intel MID platform support"
43605ef1 587 depends on X86_EXTENDED_PLATFORM
edc6bc78 588 depends on X86_PLATFORM_DEVICES
1ea7c673 589 depends on PCI
3fda5bb4 590 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 591 depends on X86_IO_APIC
7c9c3a1e 592 select SFI
4cb9b00f 593 select I2C
7c9c3a1e 594 select DW_APB_TIMER
1ea7c673 595 select APB_TIMER
1ea7c673 596 select INTEL_SCU_IPC
15a713df 597 select MFD_INTEL_MSIC
1ea7c673 598 ---help---
4cb9b00f
DC
599 Select to build a kernel capable of supporting Intel MID (Mobile
600 Internet Device) platform systems which do not have the PCI legacy
601 interfaces. If you are building for a PC class system say N here.
1ea7c673 602
4cb9b00f
DC
603 Intel MID platforms are based on an Intel processor and chipset which
604 consume less power than most of the x86 derivatives.
43605ef1 605
8bbc2a13
BD
606config X86_INTEL_QUARK
607 bool "Intel Quark platform support"
608 depends on X86_32
609 depends on X86_EXTENDED_PLATFORM
610 depends on X86_PLATFORM_DEVICES
611 depends on X86_TSC
612 depends on PCI
613 depends on PCI_GOANY
614 depends on X86_IO_APIC
615 select IOSF_MBI
616 select INTEL_IMR
9ab6eb51 617 select COMMON_CLK
8bbc2a13
BD
618 ---help---
619 Select to include support for Quark X1000 SoC.
620 Say Y here if you have a Quark based system such as the Arduino
621 compatible Intel Galileo.
622
3d48aab1
MW
623config X86_INTEL_LPSS
624 bool "Intel Low Power Subsystem Support"
5962dd22 625 depends on X86 && ACPI && PCI
3d48aab1 626 select COMMON_CLK
0f531431 627 select PINCTRL
eebb3e8d 628 select IOSF_MBI
3d48aab1
MW
629 ---help---
630 Select to build support for Intel Low Power Subsystem such as
631 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
632 things like clock tree (common clock framework) and pincontrol
633 which are needed by the LPSS peripheral drivers.
3d48aab1 634
92082a88
KX
635config X86_AMD_PLATFORM_DEVICE
636 bool "AMD ACPI2Platform devices support"
637 depends on ACPI
638 select COMMON_CLK
639 select PINCTRL
640 ---help---
641 Select to interpret AMD specific ACPI device to platform device
642 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
643 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
644 implemented under PINCTRL subsystem.
645
ced3ce76
DB
646config IOSF_MBI
647 tristate "Intel SoC IOSF Sideband support for SoC platforms"
648 depends on PCI
649 ---help---
650 This option enables sideband register access support for Intel SoC
651 platforms. On these platforms the IOSF sideband is used in lieu of
652 MSR's for some register accesses, mostly but not limited to thermal
653 and power. Drivers may query the availability of this device to
654 determine if they need the sideband in order to work on these
655 platforms. The sideband is available on the following SoC products.
656 This list is not meant to be exclusive.
657 - BayTrail
658 - Braswell
659 - Quark
660
661 You should say Y if you are running a kernel on one of these SoC's.
662
ed2226bd
DB
663config IOSF_MBI_DEBUG
664 bool "Enable IOSF sideband access through debugfs"
665 depends on IOSF_MBI && DEBUG_FS
666 ---help---
667 Select this option to expose the IOSF sideband access registers (MCR,
668 MDR, MCRX) through debugfs to write and read register information from
669 different units on the SoC. This is most useful for obtaining device
670 state information for debug and analysis. As this is a general access
671 mechanism, users of this option would have specific knowledge of the
672 device they want to access.
673
674 If you don't require the option or are in doubt, say N.
675
c5c606d9
RT
676config X86_RDC321X
677 bool "RDC R-321x SoC"
506f1d07 678 depends on X86_32
c5c606d9
RT
679 depends on X86_EXTENDED_PLATFORM
680 select M486
681 select X86_REBOOTFIXUPS
682 ---help---
683 This option is needed for RDC R-321x system-on-chip, also known
684 as R-8610-(G).
685 If you don't have one of these chips, you should say N here.
686
e0c7ae37 687config X86_32_NON_STANDARD
9c398017
IM
688 bool "Support non-standard 32-bit SMP architectures"
689 depends on X86_32 && SMP
c5c606d9 690 depends on X86_EXTENDED_PLATFORM
8f9ca475 691 ---help---
b5660ba7
PA
692 This option compiles in the bigsmp and STA2X11 default
693 subarchitectures. It is intended for a generic binary
694 kernel. If you select them all, kernel will probe it one by
695 one and will fallback to default.
d49c4288 696
c5c606d9 697# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 698
d949f36f 699config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 700 def_bool y
d949f36f
LT
701 # MCE code calls memory_failure():
702 depends on X86_MCE
703 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
704 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
705 depends on X86_64 || !SPARSEMEM
706 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 707
83125a3a
AR
708config STA2X11
709 bool "STA2X11 Companion Chip Support"
710 depends on X86_32_NON_STANDARD && PCI
b6e05477 711 select ARCH_HAS_PHYS_TO_DMA
83125a3a
AR
712 select SWIOTLB
713 select MFD_STA2X11
0145071b 714 select GPIOLIB
83125a3a
AR
715 ---help---
716 This adds support for boards based on the STA2X11 IO-Hub,
717 a.k.a. "ConneXt". The chip is used in place of the standard
718 PC chipset, so all "standard" peripherals are missing. If this
719 option is selected the kernel will still be able to boot on
720 standard PC machines.
721
82148d1d
S
722config X86_32_IRIS
723 tristate "Eurobraille/Iris poweroff module"
724 depends on X86_32
725 ---help---
726 The Iris machines from EuroBraille do not have APM or ACPI support
727 to shut themselves down properly. A special I/O sequence is
728 needed to do so, which is what this module does at
729 kernel shutdown.
730
731 This is only for Iris machines from EuroBraille.
732
733 If unused, say N.
734
ae1e9130 735config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
736 def_bool y
737 prompt "Single-depth WCHAN output"
a87d0914 738 depends on X86
8f9ca475 739 ---help---
506f1d07
SR
740 Calculate simpler /proc/<PID>/wchan values. If this option
741 is disabled then wchan values will recurse back to the
742 caller function. This provides more accurate wchan values,
743 at the expense of slightly more scheduling overhead.
744
745 If in doubt, say "Y".
746
6276a074
BP
747menuconfig HYPERVISOR_GUEST
748 bool "Linux guest support"
8f9ca475 749 ---help---
6276a074
BP
750 Say Y here to enable options for running Linux under various hyper-
751 visors. This option enables basic hypervisor detection and platform
752 setup.
506f1d07 753
6276a074
BP
754 If you say N, all options in this submenu will be skipped and
755 disabled, and Linux guest support won't be built in.
506f1d07 756
6276a074 757if HYPERVISOR_GUEST
506f1d07 758
e61bd94a
EPH
759config PARAVIRT
760 bool "Enable paravirtualization code"
8f9ca475 761 ---help---
e61bd94a
EPH
762 This changes the kernel so it can modify itself when it is run
763 under a hypervisor, potentially improving performance significantly
764 over full virtualization. However, when run without a hypervisor
765 the kernel is theoretically slower and slightly larger.
766
c00a280a
JG
767config PARAVIRT_XXL
768 bool
769
6276a074
BP
770config PARAVIRT_DEBUG
771 bool "paravirt-ops debugging"
772 depends on PARAVIRT && DEBUG_KERNEL
773 ---help---
774 Enable to debug paravirt_ops internals. Specifically, BUG if
775 a paravirt_op is missing when it is called.
776
b4ecc126
JF
777config PARAVIRT_SPINLOCKS
778 bool "Paravirtualization layer for spinlocks"
6ea30386 779 depends on PARAVIRT && SMP
b4ecc126
JF
780 ---help---
781 Paravirtualized spinlocks allow a pvops backend to replace the
782 spinlock implementation with something virtualization-friendly
783 (for example, block the virtual CPU rather than spinning).
784
4c4e4f61
R
785 It has a minimal impact on native kernels and gives a nice performance
786 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 787
4c4e4f61 788 If you are unsure how to answer this question, answer Y.
b4ecc126 789
ecca2502
ZY
790config X86_HV_CALLBACK_VECTOR
791 def_bool n
792
6276a074 793source "arch/x86/xen/Kconfig"
7af192c9 794
6276a074
BP
795config KVM_GUEST
796 bool "KVM Guest support (including kvmclock)"
797 depends on PARAVIRT
798 select PARAVIRT_CLOCK
a1c4423b 799 select ARCH_CPUIDLE_HALTPOLL
6276a074 800 default y
8f9ca475 801 ---help---
6276a074
BP
802 This option enables various optimizations for running under the KVM
803 hypervisor. It includes a paravirtualized clock, so that instead
804 of relying on a PIT (or probably other) emulation by the
805 underlying device model, the host provides the guest with
806 timing infrastructure such as time of day, and system time
506f1d07 807
a1c4423b
MT
808config ARCH_CPUIDLE_HALTPOLL
809 def_bool n
810 prompt "Disable host haltpoll when loading haltpoll driver"
811 help
812 If virtualized under KVM, disable host haltpoll.
813
7733607f
MW
814config PVH
815 bool "Support for running PVH guests"
816 ---help---
817 This option enables the PVH entry point for guest virtual machines
818 as specified in the x86/HVM direct boot ABI.
819
1e20eb85
SV
820config KVM_DEBUG_FS
821 bool "Enable debug information for KVM Guests in debugfs"
822 depends on KVM_GUEST && DEBUG_FS
1e20eb85
SV
823 ---help---
824 This option enables collection of various statistics for KVM guest.
825 Statistics are displayed in debugfs filesystem. Enabling this option
826 may incur significant overhead.
827
6276a074
BP
828config PARAVIRT_TIME_ACCOUNTING
829 bool "Paravirtual steal time accounting"
830 depends on PARAVIRT
8f9ca475 831 ---help---
6276a074
BP
832 Select this option to enable fine granularity task steal time
833 accounting. Time spent executing other tasks in parallel with
834 the current vCPU is discounted from the vCPU power. To account for
835 that, there can be a small performance impact.
836
837 If in doubt, say N here.
838
839config PARAVIRT_CLOCK
840 bool
97349135 841
4a362601
JK
842config JAILHOUSE_GUEST
843 bool "Jailhouse non-root cell support"
abde587b 844 depends on X86_64 && PCI
87e65d05 845 select X86_PM_TIMER
4a362601
JK
846 ---help---
847 This option allows to run Linux as guest in a Jailhouse non-root
848 cell. You can leave this option disabled if you only want to start
849 Jailhouse and run Linux afterwards in the root cell.
850
ec7972c9
ZY
851config ACRN_GUEST
852 bool "ACRN Guest support"
853 depends on X86_64
498ad393 854 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
855 help
856 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
857 a flexible, lightweight reference open-source hypervisor, built with
858 real-time and safety-criticality in mind. It is built for embedded
859 IOT with small footprint and real-time features. More details can be
860 found in https://projectacrn.org/.
861
6276a074 862endif #HYPERVISOR_GUEST
97349135 863
506f1d07
SR
864source "arch/x86/Kconfig.cpu"
865
866config HPET_TIMER
3c2362e6 867 def_bool X86_64
506f1d07 868 prompt "HPET Timer Support" if X86_32
8f9ca475
IM
869 ---help---
870 Use the IA-PC HPET (High Precision Event Timer) to manage
871 time in preference to the PIT and RTC, if a HPET is
872 present.
873 HPET is the next generation timer replacing legacy 8254s.
874 The HPET provides a stable time base on SMP
875 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
876 as it is off-chip. The interface used is documented
877 in the HPET spec, revision 1.
506f1d07 878
8f9ca475
IM
879 You can safely choose Y here. However, HPET will only be
880 activated if the platform and the BIOS support this feature.
881 Otherwise the 8254 will be used for timing services.
506f1d07 882
8f9ca475 883 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
884
885config HPET_EMULATE_RTC
3c2362e6 886 def_bool y
9d8af78b 887 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 888
bb24c471 889config APB_TIMER
933b9463
AC
890 def_bool y if X86_INTEL_MID
891 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
06c3df49 892 select DW_APB_TIMER
a0c3832a 893 depends on X86_INTEL_MID && SFI
bb24c471
JP
894 help
895 APB timer is the replacement for 8254, HPET on X86 MID platforms.
896 The APBT provides a stable time base on SMP
897 systems, unlike the TSC, but it is more expensive to access,
898 as it is off-chip. APB timers are always running regardless of CPU
899 C states, they are used as per CPU clockevent device when possible.
900
6a108a14 901# Mark as expert because too many people got it wrong.
506f1d07 902# The code disables itself when not needed.
7ae9392c
TP
903config DMI
904 default y
cf074402 905 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 906 bool "Enable DMI scanning" if EXPERT
8f9ca475 907 ---help---
7ae9392c
TP
908 Enabled scanning of DMI to identify machine quirks. Say Y
909 here unless you have verified that your setup is not
910 affected by entries in the DMI blacklist. Required by PNP
911 BIOS code.
912
506f1d07 913config GART_IOMMU
38901f1c 914 bool "Old AMD GART IOMMU support"
a4ce5a48 915 select IOMMU_HELPER
506f1d07 916 select SWIOTLB
23ac4ae8 917 depends on X86_64 && PCI && AMD_NB
8f9ca475 918 ---help---
ced3c42c
IM
919 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
920 GART based hardware IOMMUs.
921
922 The GART supports full DMA access for devices with 32-bit access
923 limitations, on systems with more than 3 GB. This is usually needed
924 for USB, sound, many IDE/SATA chipsets and some other devices.
925
926 Newer systems typically have a modern AMD IOMMU, supported via
927 the CONFIG_AMD_IOMMU=y config option.
928
929 In normal configurations this driver is only active when needed:
930 there's more than 3 GB of memory and the system contains a
931 32-bit limited device.
932
933 If unsure, say Y.
506f1d07
SR
934
935config CALGARY_IOMMU
936 bool "IBM Calgary IOMMU support"
a4ce5a48 937 select IOMMU_HELPER
506f1d07 938 select SWIOTLB
6ea30386 939 depends on X86_64 && PCI
8f9ca475 940 ---help---
506f1d07
SR
941 Support for hardware IOMMUs in IBM's xSeries x366 and x460
942 systems. Needed to run systems with more than 3GB of memory
943 properly with 32-bit PCI devices that do not support DAC
944 (Double Address Cycle). Calgary also supports bus level
945 isolation, where all DMAs pass through the IOMMU. This
946 prevents them from going anywhere except their intended
947 destination. This catches hard-to-find kernel bugs and
948 mis-behaving drivers and devices that do not use the DMA-API
949 properly to set up their DMA buffers. The IOMMU can be
950 turned off at boot time with the iommu=off parameter.
951 Normally the kernel will make the right choice by itself.
952 If unsure, say Y.
953
954config CALGARY_IOMMU_ENABLED_BY_DEFAULT
3c2362e6
HH
955 def_bool y
956 prompt "Should Calgary be enabled by default?"
506f1d07 957 depends on CALGARY_IOMMU
8f9ca475 958 ---help---
506f1d07
SR
959 Should Calgary be enabled by default? if you choose 'y', Calgary
960 will be used (if it exists). If you choose 'n', Calgary will not be
961 used even if it exists. If you choose 'n' and would like to use
962 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
963 If unsure, say Y.
506f1d07 964
1184dc2f 965config MAXSMP
ddb0c5a6 966 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 967 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 968 select CPUMASK_OFFSTACK
8f9ca475 969 ---help---
ddb0c5a6 970 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 971 If unsure, say N.
506f1d07 972
aec6487e
IM
973#
974# The maximum number of CPUs supported:
975#
976# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
977# and which can be configured interactively in the
978# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
979#
980# The ranges are different on 32-bit and 64-bit kernels, depending on
981# hardware capabilities and scalability features of the kernel.
982#
983# ( If MAXSMP is enabled we just use the highest possible value and disable
984# interactive configuration. )
985#
986
987config NR_CPUS_RANGE_BEGIN
a0d0bb4d 988 int
aec6487e
IM
989 default NR_CPUS_RANGE_END if MAXSMP
990 default 1 if !SMP
991 default 2
a0d0bb4d 992
aec6487e 993config NR_CPUS_RANGE_END
a0d0bb4d 994 int
aec6487e
IM
995 depends on X86_32
996 default 64 if SMP && X86_BIGSMP
997 default 8 if SMP && !X86_BIGSMP
998 default 1 if !SMP
a0d0bb4d 999
aec6487e 1000config NR_CPUS_RANGE_END
a0d0bb4d 1001 int
aec6487e
IM
1002 depends on X86_64
1003 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK)
1004 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
1005 default 1 if !SMP
a0d0bb4d 1006
aec6487e 1007config NR_CPUS_DEFAULT
a0d0bb4d
RD
1008 int
1009 depends on X86_32
aec6487e
IM
1010 default 32 if X86_BIGSMP
1011 default 8 if SMP
1012 default 1 if !SMP
a0d0bb4d 1013
aec6487e 1014config NR_CPUS_DEFAULT
a0d0bb4d
RD
1015 int
1016 depends on X86_64
aec6487e
IM
1017 default 8192 if MAXSMP
1018 default 64 if SMP
1019 default 1 if !SMP
a0d0bb4d 1020
506f1d07 1021config NR_CPUS
36f5101a 1022 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
1023 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1024 default NR_CPUS_DEFAULT
8f9ca475 1025 ---help---
506f1d07 1026 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1027 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1028 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1029 minimum value which makes sense is 2.
1030
aec6487e
IM
1031 This is purely to save memory: each supported CPU adds about 8KB
1032 to the kernel image.
506f1d07
SR
1033
1034config SCHED_SMT
dbe73364 1035 def_bool y if SMP
506f1d07
SR
1036
1037config SCHED_MC
3c2362e6
HH
1038 def_bool y
1039 prompt "Multi-core scheduler support"
c8e56d20 1040 depends on SMP
8f9ca475 1041 ---help---
506f1d07
SR
1042 Multi-core scheduler support improves the CPU scheduler's decision
1043 making when dealing with multi-core CPU chips at a cost of slightly
1044 increased overhead in some places. If unsure say N here.
1045
de966cf4
TC
1046config SCHED_MC_PRIO
1047 bool "CPU core priorities scheduler support"
0a21fc12
IM
1048 depends on SCHED_MC && CPU_SUP_INTEL
1049 select X86_INTEL_PSTATE
1050 select CPU_FREQ
de966cf4 1051 default y
5e76b2ab 1052 ---help---
0a21fc12
IM
1053 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1054 core ordering determined at manufacturing time, which allows
1055 certain cores to reach higher turbo frequencies (when running
1056 single threaded workloads) than others.
de966cf4 1057
0a21fc12
IM
1058 Enabling this kernel feature teaches the scheduler about
1059 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1060 scheduler's CPU selection logic accordingly, so that higher
1061 overall system performance can be achieved.
de966cf4 1062
0a21fc12 1063 This feature will have no effect on CPUs without this feature.
de966cf4 1064
0a21fc12 1065 If unsure say Y here.
5e76b2ab 1066
30b8b006
TG
1067config UP_LATE_INIT
1068 def_bool y
ba360f88 1069 depends on !SMP && X86_LOCAL_APIC
30b8b006 1070
506f1d07 1071config X86_UP_APIC
50849eef
JB
1072 bool "Local APIC support on uniprocessors" if !PCI_MSI
1073 default PCI_MSI
38a1dfda 1074 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
8f9ca475 1075 ---help---
506f1d07
SR
1076 A local APIC (Advanced Programmable Interrupt Controller) is an
1077 integrated interrupt controller in the CPU. If you have a single-CPU
1078 system which has a processor with a local APIC, you can say Y here to
1079 enable and use it. If you say Y here even though your machine doesn't
1080 have a local APIC, then the kernel will still run with no slowdown at
1081 all. The local APIC supports CPU-generated self-interrupts (timer,
1082 performance counters), and the NMI watchdog which detects hard
1083 lockups.
1084
1085config X86_UP_IOAPIC
1086 bool "IO-APIC support on uniprocessors"
1087 depends on X86_UP_APIC
8f9ca475 1088 ---help---
506f1d07
SR
1089 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1090 SMP-capable replacement for PC-style interrupt controllers. Most
1091 SMP systems and many recent uniprocessor systems have one.
1092
1093 If you have a single-CPU system with an IO-APIC, you can say Y here
1094 to use it. If you say Y here even though your machine doesn't have
1095 an IO-APIC, then the kernel will still run with no slowdown at all.
1096
1097config X86_LOCAL_APIC
3c2362e6 1098 def_bool y
0dbc6078 1099 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1100 select IRQ_DOMAIN_HIERARCHY
52f518a3 1101 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
506f1d07
SR
1102
1103config X86_IO_APIC
b1da1e71
JB
1104 def_bool y
1105 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1106
41b9eb26
SA
1107config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1108 bool "Reroute for broken boot IRQs"
41b9eb26 1109 depends on X86_IO_APIC
8f9ca475 1110 ---help---
41b9eb26
SA
1111 This option enables a workaround that fixes a source of
1112 spurious interrupts. This is recommended when threaded
1113 interrupt handling is used on systems where the generation of
1114 superfluous "boot interrupts" cannot be disabled.
1115
1116 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1117 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1118 kernel does during interrupt handling). On chipsets where this
1119 boot IRQ generation cannot be disabled, this workaround keeps
1120 the original IRQ line masked so that only the equivalent "boot
1121 IRQ" is delivered to the CPUs. The workaround also tells the
1122 kernel to set up the IRQ handler on the boot IRQ line. In this
1123 way only one interrupt is delivered to the kernel. Otherwise
1124 the spurious second interrupt may cause the kernel to bring
1125 down (vital) interrupt lines.
1126
1127 Only affects "broken" chipsets. Interrupt sharing may be
1128 increased on these systems.
1129
506f1d07 1130config X86_MCE
bab9bc65 1131 bool "Machine Check / overheating reporting"
648ed940 1132 select GENERIC_ALLOCATOR
e57dbaf7 1133 default y
506f1d07 1134 ---help---
bab9bc65
AK
1135 Machine Check support allows the processor to notify the
1136 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1137 The action the kernel takes depends on the severity of the problem,
bab9bc65 1138 ranging from warning messages to halting the machine.
4efc0670 1139
5de97c9f
TL
1140config X86_MCELOG_LEGACY
1141 bool "Support for deprecated /dev/mcelog character device"
1142 depends on X86_MCE
1143 ---help---
1144 Enable support for /dev/mcelog which is needed by the old mcelog
1145 userspace logging daemon. Consider switching to the new generation
1146 rasdaemon solution.
1147
506f1d07 1148config X86_MCE_INTEL
3c2362e6
HH
1149 def_bool y
1150 prompt "Intel MCE features"
c1ebf835 1151 depends on X86_MCE && X86_LOCAL_APIC
8f9ca475 1152 ---help---
506f1d07
SR
1153 Additional support for intel specific MCE features such as
1154 the thermal monitor.
1155
1156config X86_MCE_AMD
3c2362e6
HH
1157 def_bool y
1158 prompt "AMD MCE features"
f5382de9 1159 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
8f9ca475 1160 ---help---
506f1d07
SR
1161 Additional support for AMD specific MCE features such as
1162 the DRAM Error Threshold.
1163
4efc0670 1164config X86_ANCIENT_MCE
6fc108a0 1165 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1166 depends on X86_32 && X86_MCE
cd13adcc
HS
1167 ---help---
1168 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1169 systems. These typically need to be enabled explicitly on the command
cd13adcc 1170 line.
4efc0670 1171
b2762686
AK
1172config X86_MCE_THRESHOLD
1173 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1174 def_bool y
b2762686 1175
ea149b36 1176config X86_MCE_INJECT
bc8e80d5 1177 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36
AK
1178 tristate "Machine check injector support"
1179 ---help---
1180 Provide support for injecting machine checks for testing purposes.
1181 If you don't know what a machine check is and you don't do kernel
1182 QA it is safe to say n.
1183
4efc0670
AK
1184config X86_THERMAL_VECTOR
1185 def_bool y
5bb38adc 1186 depends on X86_MCE_INTEL
4efc0670 1187
07dc900e 1188source "arch/x86/events/Kconfig"
e633c65a 1189
5aef51c3 1190config X86_LEGACY_VM86
1e642812 1191 bool "Legacy VM86 support"
506f1d07 1192 depends on X86_32
8f9ca475 1193 ---help---
5aef51c3
AL
1194 This option allows user programs to put the CPU into V8086
1195 mode, which is an 80286-era approximation of 16-bit real mode.
1196
1197 Some very old versions of X and/or vbetool require this option
1198 for user mode setting. Similarly, DOSEMU will use it if
1199 available to accelerate real mode DOS programs. However, any
1200 recent version of DOSEMU, X, or vbetool should be fully
1201 functional even without kernel VM86 support, as they will all
1e642812
IM
1202 fall back to software emulation. Nevertheless, if you are using
1203 a 16-bit DOS program where 16-bit performance matters, vm86
1204 mode might be faster than emulation and you might want to
1205 enable this option.
5aef51c3 1206
1e642812
IM
1207 Note that any app that works on a 64-bit kernel is unlikely to
1208 need this option, as 64-bit kernels don't, and can't, support
1209 V8086 mode. This option is also unrelated to 16-bit protected
1210 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1211
1e642812
IM
1212 Enabling this option increases the complexity of the kernel
1213 and slows down exception handling a tiny bit.
5aef51c3 1214
1e642812 1215 If unsure, say N here.
5aef51c3
AL
1216
1217config VM86
1218 bool
1219 default X86_LEGACY_VM86
34273f41
PA
1220
1221config X86_16BIT
1222 bool "Enable support for 16-bit segments" if EXPERT
1223 default y
a5b9e5a2 1224 depends on MODIFY_LDT_SYSCALL
34273f41
PA
1225 ---help---
1226 This option is required by programs like Wine to run 16-bit
1227 protected mode legacy code on x86 processors. Disabling
1228 this option saves about 300 bytes on i386, or around 6K text
1229 plus 16K runtime memory on x86-64,
1230
1231config X86_ESPFIX32
1232 def_bool y
1233 depends on X86_16BIT && X86_32
506f1d07 1234
197725de
PA
1235config X86_ESPFIX64
1236 def_bool y
34273f41 1237 depends on X86_16BIT && X86_64
506f1d07 1238
1ad83c85
AL
1239config X86_VSYSCALL_EMULATION
1240 bool "Enable vsyscall emulation" if EXPERT
1241 default y
1242 depends on X86_64
1243 ---help---
1244 This enables emulation of the legacy vsyscall page. Disabling
1245 it is roughly equivalent to booting with vsyscall=none, except
1246 that it will also disable the helpful warning if a program
1247 tries to use a vsyscall. With this option set to N, offending
1248 programs will just segfault, citing addresses of the form
1249 0xffffffffff600?00.
1250
1251 This option is required by many programs built before 2013, and
1252 care should be used even with newer programs if set to N.
1253
1254 Disabling this option saves about 7K of kernel size and
1255 possibly 4K of additional runtime pagetable memory.
1256
506f1d07
SR
1257config TOSHIBA
1258 tristate "Toshiba Laptop support"
1259 depends on X86_32
1260 ---help---
1261 This adds a driver to safely access the System Management Mode of
1262 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1263 not work on models with a Phoenix BIOS. The System Management Mode
1264 is used to set the BIOS and power saving options on Toshiba portables.
1265
1266 For information on utilities to make use of this driver see the
1267 Toshiba Linux utilities web site at:
1268 <http://www.buzzard.org.uk/toshiba/>.
1269
1270 Say Y if you intend to run this kernel on a Toshiba portable.
1271 Say N otherwise.
1272
1273config I8K
039ae585 1274 tristate "Dell i8k legacy laptop support"
949a9d70 1275 select HWMON
039ae585 1276 select SENSORS_DELL_SMM
506f1d07 1277 ---help---
039ae585
PR
1278 This option enables legacy /proc/i8k userspace interface in hwmon
1279 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1280 temperature and allows controlling fan speeds of Dell laptops via
1281 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1282 it reports also power and hotkey status. For fan speed control is
1283 needed userspace package i8kutils.
1284
1285 Say Y if you intend to run this kernel on old Dell laptops or want to
1286 use userspace package i8kutils.
506f1d07
SR
1287 Say N otherwise.
1288
1289config X86_REBOOTFIXUPS
9ba16087
JB
1290 bool "Enable X86 board specific fixups for reboot"
1291 depends on X86_32
506f1d07
SR
1292 ---help---
1293 This enables chipset and/or board specific fixups to be done
1294 in order to get reboot to work correctly. This is only needed on
1295 some combinations of hardware and BIOS. The symptom, for which
1296 this config is intended, is when reboot ends with a stalled/hung
1297 system.
1298
1299 Currently, the only fixup is for the Geode machines using
5e3a77e9 1300 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1301
1302 Say Y if you want to enable the fixup. Currently, it's safe to
1303 enable this option even if you don't need it.
1304 Say N otherwise.
1305
1306config MICROCODE
9a2bc335
BP
1307 bool "CPU microcode loading support"
1308 default y
80030e3d 1309 depends on CPU_SUP_AMD || CPU_SUP_INTEL
506f1d07
SR
1310 select FW_LOADER
1311 ---help---
1312 If you say Y here, you will be able to update the microcode on
5f9c01aa
BP
1313 Intel and AMD processors. The Intel support is for the IA32 family,
1314 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1315 AMD support is for families 0x10 and later. You will obviously need
1316 the actual microcode binary data itself which is not shipped with
1317 the Linux kernel.
1318
1319 The preferred method to load microcode from a detached initrd is described
cb1aaebe 1320 in Documentation/x86/microcode.rst. For that you need to enable
5f9c01aa
BP
1321 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1322 initrd for microcode blobs.
1323
c508c46e
BG
1324 In addition, you can build the microcode into the kernel. For that you
1325 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1326 config option.
506f1d07 1327
8d86f390 1328config MICROCODE_INTEL
e43f6e67 1329 bool "Intel microcode loading support"
8f9ca475
IM
1330 depends on MICROCODE
1331 default MICROCODE
1332 select FW_LOADER
1333 ---help---
1334 This options enables microcode patch loading support for Intel
1335 processors.
1336
b8989db9
A
1337 For the current Intel microcode data package go to
1338 <https://downloadcenter.intel.com> and search for
1339 'Linux Processor Microcode Data File'.
8d86f390 1340
80cc9f10 1341config MICROCODE_AMD
e43f6e67 1342 bool "AMD microcode loading support"
8f9ca475
IM
1343 depends on MICROCODE
1344 select FW_LOADER
1345 ---help---
1346 If you select this option, microcode patch loading support for AMD
1347 processors will be enabled.
80cc9f10 1348
8f9ca475 1349config MICROCODE_OLD_INTERFACE
c02f48e0
BP
1350 bool "Ancient loading interface (DEPRECATED)"
1351 default n
506f1d07 1352 depends on MICROCODE
c02f48e0
BP
1353 ---help---
1354 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1355 which was used by userspace tools like iucode_tool and microcode.ctl.
1356 It is inadequate because it runs too late to be able to properly
1357 load microcode on a machine and it needs special tools. Instead, you
1358 should've switched to the early loading method with the initrd or
cb1aaebe 1359 builtin microcode by now: Documentation/x86/microcode.rst
506f1d07
SR
1360
1361config X86_MSR
1362 tristate "/dev/cpu/*/msr - Model-specific register support"
8f9ca475 1363 ---help---
506f1d07
SR
1364 This device gives privileged processes access to the x86
1365 Model-Specific Registers (MSRs). It is a character device with
1366 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1367 MSR accesses are directed to a specific CPU on multi-processor
1368 systems.
1369
1370config X86_CPUID
1371 tristate "/dev/cpu/*/cpuid - CPU information support"
8f9ca475 1372 ---help---
506f1d07
SR
1373 This device gives processes access to the x86 CPUID instruction to
1374 be executed on a specific processor. It is a character device
1375 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1376 /dev/cpu/31/cpuid.
1377
1378choice
1379 prompt "High Memory Support"
6fc108a0 1380 default HIGHMEM4G
506f1d07
SR
1381 depends on X86_32
1382
1383config NOHIGHMEM
1384 bool "off"
506f1d07
SR
1385 ---help---
1386 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1387 However, the address space of 32-bit x86 processors is only 4
1388 Gigabytes large. That means that, if you have a large amount of
1389 physical memory, not all of it can be "permanently mapped" by the
1390 kernel. The physical memory that's not permanently mapped is called
1391 "high memory".
1392
1393 If you are compiling a kernel which will never run on a machine with
1394 more than 1 Gigabyte total physical RAM, answer "off" here (default
1395 choice and suitable for most users). This will result in a "3GB/1GB"
1396 split: 3GB are mapped so that each process sees a 3GB virtual memory
1397 space and the remaining part of the 4GB virtual memory space is used
1398 by the kernel to permanently map as much physical memory as
1399 possible.
1400
1401 If the machine has between 1 and 4 Gigabytes physical RAM, then
1402 answer "4GB" here.
1403
1404 If more than 4 Gigabytes is used then answer "64GB" here. This
1405 selection turns Intel PAE (Physical Address Extension) mode on.
1406 PAE implements 3-level paging on IA32 processors. PAE is fully
1407 supported by Linux, PAE mode is implemented on all recent Intel
1408 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1409 then the kernel will not boot on CPUs that don't support PAE!
1410
1411 The actual amount of total physical memory will either be
1412 auto detected or can be forced by using a kernel command line option
1413 such as "mem=256M". (Try "man bootparam" or see the documentation of
1414 your boot loader (lilo or loadlin) about how to pass options to the
1415 kernel at boot time.)
1416
1417 If unsure, say "off".
1418
1419config HIGHMEM4G
1420 bool "4GB"
8f9ca475 1421 ---help---
506f1d07
SR
1422 Select this if you have a 32-bit processor and between 1 and 4
1423 gigabytes of physical RAM.
1424
1425config HIGHMEM64G
1426 bool "64GB"
69b8d3fc 1427 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
506f1d07 1428 select X86_PAE
8f9ca475 1429 ---help---
506f1d07
SR
1430 Select this if you have a 32-bit processor and more than 4
1431 gigabytes of physical RAM.
1432
1433endchoice
1434
1435choice
6a108a14 1436 prompt "Memory split" if EXPERT
506f1d07
SR
1437 default VMSPLIT_3G
1438 depends on X86_32
8f9ca475 1439 ---help---
506f1d07
SR
1440 Select the desired split between kernel and user memory.
1441
1442 If the address range available to the kernel is less than the
1443 physical memory installed, the remaining memory will be available
1444 as "high memory". Accessing high memory is a little more costly
1445 than low memory, as it needs to be mapped into the kernel first.
1446 Note that increasing the kernel address space limits the range
1447 available to user programs, making the address space there
1448 tighter. Selecting anything other than the default 3G/1G split
1449 will also likely make your kernel incompatible with binary-only
1450 kernel modules.
1451
1452 If you are not absolutely sure what you are doing, leave this
1453 option alone!
1454
1455 config VMSPLIT_3G
1456 bool "3G/1G user/kernel split"
1457 config VMSPLIT_3G_OPT
1458 depends on !X86_PAE
1459 bool "3G/1G user/kernel split (for full 1G low memory)"
1460 config VMSPLIT_2G
1461 bool "2G/2G user/kernel split"
1462 config VMSPLIT_2G_OPT
1463 depends on !X86_PAE
1464 bool "2G/2G user/kernel split (for full 2G low memory)"
1465 config VMSPLIT_1G
1466 bool "1G/3G user/kernel split"
1467endchoice
1468
1469config PAGE_OFFSET
1470 hex
1471 default 0xB0000000 if VMSPLIT_3G_OPT
1472 default 0x80000000 if VMSPLIT_2G
1473 default 0x78000000 if VMSPLIT_2G_OPT
1474 default 0x40000000 if VMSPLIT_1G
1475 default 0xC0000000
1476 depends on X86_32
1477
1478config HIGHMEM
3c2362e6 1479 def_bool y
506f1d07 1480 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1481
1482config X86_PAE
9ba16087 1483 bool "PAE (Physical Address Extension) Support"
506f1d07 1484 depends on X86_32 && !HIGHMEM4G
d4a451d5 1485 select PHYS_ADDR_T_64BIT
9d99c712 1486 select SWIOTLB
8f9ca475 1487 ---help---
506f1d07
SR
1488 PAE is required for NX support, and furthermore enables
1489 larger swapspace support for non-overcommit purposes. It
1490 has the cost of more pagetable lookup overhead, and also
1491 consumes more pagetable space per process.
1492
77ef56e4
KS
1493config X86_5LEVEL
1494 bool "Enable 5-level page tables support"
eedb92ab 1495 select DYNAMIC_MEMORY_LAYOUT
162434e7 1496 select SPARSEMEM_VMEMMAP
77ef56e4
KS
1497 depends on X86_64
1498 ---help---
1499 5-level paging enables access to larger address space:
1500 upto 128 PiB of virtual address space and 4 PiB of
1501 physical address space.
1502
1503 It will be supported by future Intel CPUs.
1504
6657fca0
KS
1505 A kernel with the option enabled can be booted on machines that
1506 support 4- or 5-level paging.
77ef56e4 1507
cb1aaebe 1508 See Documentation/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1509 information.
1510
1511 Say N if unsure.
1512
10971ab2 1513config X86_DIRECT_GBPAGES
e5008abe 1514 def_bool y
2e1da13f 1515 depends on X86_64
8f9ca475 1516 ---help---
10971ab2
IM
1517 Certain kernel features effectively disable kernel
1518 linear 1 GB mappings (even if the CPU otherwise
1519 supports them), so don't confuse the user by printing
1520 that we have them enabled.
9e899816 1521
5c280cf6
TG
1522config X86_CPA_STATISTICS
1523 bool "Enable statistic for Change Page Attribute"
1524 depends on DEBUG_FS
1525 ---help---
1526 Expose statistics about the Change Page Attribute mechanims, which
a943245a 1527 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1528 page mappings when mapping protections are changed.
1529
7744ccdb
TL
1530config AMD_MEM_ENCRYPT
1531 bool "AMD Secure Memory Encryption (SME) support"
1532 depends on X86_64 && CPU_SUP_AMD
94d49eb3 1533 select DYNAMIC_PHYSICAL_MASK
ce9084ba 1534 select ARCH_USE_MEMREMAP_PROT
9087c375 1535 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
7744ccdb
TL
1536 ---help---
1537 Say yes to enable support for the encryption of system memory.
1538 This requires an AMD processor that supports Secure Memory
1539 Encryption (SME).
1540
1541config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1542 bool "Activate AMD Secure Memory Encryption (SME) by default"
1543 default y
1544 depends on AMD_MEM_ENCRYPT
1545 ---help---
1546 Say yes to have system memory encrypted by default if running on
1547 an AMD processor that supports Secure Memory Encryption (SME).
1548
1549 If set to Y, then the encryption of system memory can be
1550 deactivated with the mem_encrypt=off command line option.
1551
1552 If set to N, then the encryption of system memory can be
1553 activated with the mem_encrypt=on command line option.
1554
506f1d07
SR
1555# Common NUMA Features
1556config NUMA
fd51b2d7 1557 bool "Numa Memory Allocation and Scheduler Support"
506f1d07 1558 depends on SMP
b5660ba7
PA
1559 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1560 default y if X86_BIGSMP
8f9ca475 1561 ---help---
506f1d07 1562 Enable NUMA (Non Uniform Memory Access) support.
fd51b2d7 1563
506f1d07
SR
1564 The kernel will try to allocate memory used by a CPU on the
1565 local memory controller of the CPU and add some more
1566 NUMA awareness to the kernel.
1567
c280ea5e 1568 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1569 (or later), AMD Opteron, or EM64T NUMA.
1570
b5660ba7 1571 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1572 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1573
1574 Otherwise, you should say N.
506f1d07 1575
eec1d4fa 1576config AMD_NUMA
3c2362e6
HH
1577 def_bool y
1578 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1579 depends on X86_64 && NUMA && PCI
8f9ca475 1580 ---help---
eec1d4fa
HR
1581 Enable AMD NUMA node topology detection. You should say Y here if
1582 you have a multi processor AMD system. This uses an old method to
1583 read the NUMA configuration directly from the builtin Northbridge
1584 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1585 which also takes priority if both are compiled in.
506f1d07
SR
1586
1587config X86_64_ACPI_NUMA
3c2362e6
HH
1588 def_bool y
1589 prompt "ACPI NUMA detection"
506f1d07
SR
1590 depends on X86_64 && NUMA && ACPI && PCI
1591 select ACPI_NUMA
8f9ca475 1592 ---help---
506f1d07
SR
1593 Enable ACPI SRAT based node topology detection.
1594
6ec6e0d9
SS
1595# Some NUMA nodes have memory ranges that span
1596# other nodes. Even though a pfn is valid and
1597# between a node's start and end pfns, it may not
1598# reside on that node. See memmap_init_zone()
1599# for details.
1600config NODES_SPAN_OTHER_NODES
1601 def_bool y
1602 depends on X86_64_ACPI_NUMA
1603
506f1d07
SR
1604config NUMA_EMU
1605 bool "NUMA emulation"
1b7e03ef 1606 depends on NUMA
8f9ca475 1607 ---help---
506f1d07
SR
1608 Enable NUMA emulation. A flat machine will be split
1609 into virtual nodes when booted with "numa=fake=N", where N is the
1610 number of nodes. This is only useful for debugging.
1611
1612config NODES_SHIFT
d25e26b6 1613 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1614 range 1 10
1615 default "10" if MAXSMP
506f1d07 1616 default "6" if X86_64
506f1d07
SR
1617 default "3"
1618 depends on NEED_MULTIPLE_NODES
8f9ca475 1619 ---help---
1184dc2f 1620 Specify the maximum number of NUMA Nodes available on the target
692105b8 1621 system. Increases memory reserved to accommodate various tables.
506f1d07 1622
506f1d07 1623config ARCH_HAVE_MEMORY_PRESENT
3c2362e6 1624 def_bool y
506f1d07 1625 depends on X86_32 && DISCONTIGMEM
506f1d07 1626
506f1d07
SR
1627config ARCH_FLATMEM_ENABLE
1628 def_bool y
3b16651f 1629 depends on X86_32 && !NUMA
506f1d07
SR
1630
1631config ARCH_DISCONTIGMEM_ENABLE
2792107d 1632 def_bool n
b263295d 1633 depends on NUMA && X86_32
2792107d 1634 depends on BROKEN
b263295d 1635
506f1d07
SR
1636config ARCH_SPARSEMEM_ENABLE
1637 def_bool y
6ea30386 1638 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1639 select SPARSEMEM_STATIC if X86_32
1640 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1641
3b16651f 1642config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1643 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1644
506f1d07
SR
1645config ARCH_SELECT_MEMORY_MODEL
1646 def_bool y
b263295d 1647 depends on ARCH_SPARSEMEM_ENABLE
506f1d07
SR
1648
1649config ARCH_MEMORY_PROBE
a0842b70 1650 bool "Enable sysfs memory/probe interface"
3120e25e 1651 depends on X86_64 && MEMORY_HOTPLUG
a0842b70
TK
1652 help
1653 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1654 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1655 If you are unsure how to answer this question, answer N.
506f1d07 1656
3b16651f
TH
1657config ARCH_PROC_KCORE_TEXT
1658 def_bool y
1659 depends on X86_64 && PROC_KCORE
1660
a29815a3
AK
1661config ILLEGAL_POINTER_VALUE
1662 hex
1663 default 0 if X86_32
1664 default 0xdead000000000000 if X86_64
1665
7a67832c
DW
1666config X86_PMEM_LEGACY_DEVICE
1667 bool
1668
ec776ef6 1669config X86_PMEM_LEGACY
7a67832c 1670 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1671 depends on PHYS_ADDR_T_64BIT
1672 depends on BLK_DEV
7a67832c 1673 select X86_PMEM_LEGACY_DEVICE
9f53f9fa 1674 select LIBNVDIMM
ec776ef6
CH
1675 help
1676 Treat memory marked using the non-standard e820 type of 12 as used
1677 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1678 The kernel will offer these regions to the 'pmem' driver so
1679 they can be used for persistent storage.
1680
1681 Say Y if unsure.
1682
506f1d07
SR
1683config HIGHPTE
1684 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1685 depends on HIGHMEM
8f9ca475 1686 ---help---
506f1d07
SR
1687 The VM uses one page table entry for each page of physical memory.
1688 For systems with a lot of RAM, this can be wasteful of precious
1689 low memory. Setting this option will put user-space page table
1690 entries in high memory.
1691
9f077871 1692config X86_CHECK_BIOS_CORRUPTION
8f9ca475
IM
1693 bool "Check for low memory corruption"
1694 ---help---
1695 Periodically check for memory corruption in low memory, which
1696 is suspected to be caused by BIOS. Even when enabled in the
1697 configuration, it is disabled at runtime. Enable it by
1698 setting "memory_corruption_check=1" on the kernel command
1699 line. By default it scans the low 64k of memory every 60
1700 seconds; see the memory_corruption_check_size and
1701 memory_corruption_check_period parameters in
8c27ceff 1702 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1703
1704 When enabled with the default parameters, this option has
1705 almost no overhead, as it reserves a relatively small amount
1706 of memory and scans it infrequently. It both detects corruption
1707 and prevents it from affecting the running system.
1708
1709 It is, however, intended as a diagnostic tool; if repeatable
1710 BIOS-originated corruption always affects the same memory,
1711 you can use memmap= to prevent the kernel from using that
1712 memory.
9f077871 1713
c885df50 1714config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1715 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1716 depends on X86_CHECK_BIOS_CORRUPTION
1717 default y
8f9ca475
IM
1718 ---help---
1719 Set whether the default state of memory_corruption_check is
1720 on or off.
c885df50 1721
9ea77bdb 1722config X86_RESERVE_LOW
d0cd7425
PA
1723 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1724 default 64
1725 range 4 640
8f9ca475 1726 ---help---
d0cd7425
PA
1727 Specify the amount of low memory to reserve for the BIOS.
1728
1729 The first page contains BIOS data structures that the kernel
1730 must not use, so that page must always be reserved.
1731
1732 By default we reserve the first 64K of physical RAM, as a
1733 number of BIOSes are known to corrupt that memory range
1734 during events such as suspend/resume or monitor cable
1735 insertion, so it must not be used by the kernel.
fc381519 1736
d0cd7425
PA
1737 You can set this to 4 if you are absolutely sure that you
1738 trust the BIOS to get all its memory reservations and usages
1739 right. If you know your BIOS have problems beyond the
1740 default 64K area, you can set this to 640 to avoid using the
1741 entire low memory range.
fc381519 1742
d0cd7425
PA
1743 If you have doubts about the BIOS (e.g. suspend/resume does
1744 not work or there's kernel crashes after certain hardware
1745 hotplug events) then you might want to enable
1746 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1747 typical corruption patterns.
fc381519 1748
d0cd7425 1749 Leave this to the default value of 64 if you are unsure.
fc381519 1750
506f1d07
SR
1751config MATH_EMULATION
1752 bool
a5b9e5a2 1753 depends on MODIFY_LDT_SYSCALL
506f1d07
SR
1754 prompt "Math emulation" if X86_32
1755 ---help---
1756 Linux can emulate a math coprocessor (used for floating point
1757 operations) if you don't have one. 486DX and Pentium processors have
1758 a math coprocessor built in, 486SX and 386 do not, unless you added
1759 a 487DX or 387, respectively. (The messages during boot time can
1760 give you some hints here ["man dmesg"].) Everyone needs either a
1761 coprocessor or this emulation.
1762
1763 If you don't have a math coprocessor, you need to say Y here; if you
1764 say Y here even though you have a coprocessor, the coprocessor will
1765 be used nevertheless. (This behavior can be changed with the kernel
1766 command line option "no387", which comes handy if your coprocessor
1767 is broken. Try "man bootparam" or see the documentation of your boot
1768 loader (lilo or loadlin) about how to pass options to the kernel at
1769 boot time.) This means that it is a good idea to say Y here if you
1770 intend to use this kernel on different machines.
1771
1772 More information about the internals of the Linux math coprocessor
1773 emulation can be found in <file:arch/x86/math-emu/README>.
1774
1775 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1776 kernel, it won't hurt.
1777
1778config MTRR
6fc108a0 1779 def_bool y
6a108a14 1780 prompt "MTRR (Memory Type Range Register) support" if EXPERT
506f1d07
SR
1781 ---help---
1782 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1783 the Memory Type Range Registers (MTRRs) may be used to control
1784 processor access to memory ranges. This is most useful if you have
1785 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1786 allows bus write transfers to be combined into a larger transfer
1787 before bursting over the PCI/AGP bus. This can increase performance
1788 of image write operations 2.5 times or more. Saying Y here creates a
1789 /proc/mtrr file which may be used to manipulate your processor's
1790 MTRRs. Typically the X server should use this.
1791
1792 This code has a reasonably generic interface so that similar
1793 control registers on other processors can be easily supported
1794 as well:
1795
1796 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1797 Registers (ARRs) which provide a similar functionality to MTRRs. For
1798 these, the ARRs are used to emulate the MTRRs.
1799 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1800 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1801 write-combining. All of these processors are supported by this code
1802 and it makes sense to say Y here if you have one of them.
1803
1804 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1805 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1806 can lead to all sorts of problems, so it's good to say Y here.
1807
1808 You can safely say Y even if your machine doesn't have MTRRs, you'll
1809 just add about 9 KB to your kernel.
1810
cb1aaebe 1811 See <file:Documentation/x86/mtrr.rst> for more information.
506f1d07 1812
95ffa243 1813config MTRR_SANITIZER
2ffb3501 1814 def_bool y
95ffa243
YL
1815 prompt "MTRR cleanup support"
1816 depends on MTRR
8f9ca475 1817 ---help---
aba3728c
TG
1818 Convert MTRR layout from continuous to discrete, so X drivers can
1819 add writeback entries.
95ffa243 1820
aba3728c 1821 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1822 The largest mtrr entry size for a continuous block can be set with
aba3728c 1823 mtrr_chunk_size.
95ffa243 1824
2ffb3501 1825 If unsure, say Y.
95ffa243
YL
1826
1827config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1828 int "MTRR cleanup enable value (0-1)"
1829 range 0 1
1830 default "0"
95ffa243 1831 depends on MTRR_SANITIZER
8f9ca475 1832 ---help---
f5098d62 1833 Enable mtrr cleanup default value
95ffa243 1834
12031a62
YL
1835config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1836 int "MTRR cleanup spare reg num (0-7)"
1837 range 0 7
1838 default "1"
1839 depends on MTRR_SANITIZER
8f9ca475 1840 ---help---
12031a62 1841 mtrr cleanup spare entries default, it can be changed via
aba3728c 1842 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1843
2e5d9c85 1844config X86_PAT
6fc108a0 1845 def_bool y
6a108a14 1846 prompt "x86 PAT support" if EXPERT
2a8a2719 1847 depends on MTRR
8f9ca475 1848 ---help---
2e5d9c85 1849 Use PAT attributes to setup page level cache control.
042b78e4 1850
2e5d9c85 1851 PATs are the modern equivalents of MTRRs and are much more
1852 flexible than MTRRs.
1853
1854 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1855 spontaneous reboots) or a non-working video driver.
2e5d9c85 1856
1857 If unsure, say Y.
1858
46cf98cd
VP
1859config ARCH_USES_PG_UNCACHED
1860 def_bool y
1861 depends on X86_PAT
1862
628c6246
PA
1863config ARCH_RANDOM
1864 def_bool y
1865 prompt "x86 architectural random number generator" if EXPERT
1866 ---help---
1867 Enable the x86 architectural RDRAND instruction
1868 (Intel Bull Mountain technology) to generate random numbers.
1869 If supported, this is a high bandwidth, cryptographically
1870 secure hardware random number generator.
1871
51ae4a2d
PA
1872config X86_SMAP
1873 def_bool y
1874 prompt "Supervisor Mode Access Prevention" if EXPERT
1875 ---help---
1876 Supervisor Mode Access Prevention (SMAP) is a security
1877 feature in newer Intel processors. There is a small
1878 performance cost if this enabled and turned on; there is
1879 also a small increase in the kernel size if this is enabled.
1880
1881 If unsure, say Y.
1882
aa35f896 1883config X86_INTEL_UMIP
796ebc81 1884 def_bool y
aa35f896
RN
1885 depends on CPU_SUP_INTEL
1886 prompt "Intel User Mode Instruction Prevention" if EXPERT
1887 ---help---
1888 The User Mode Instruction Prevention (UMIP) is a security
1889 feature in newer Intel processors. If enabled, a general
796ebc81
RN
1890 protection fault is issued if the SGDT, SLDT, SIDT, SMSW
1891 or STR instructions are executed in user mode. These instructions
1892 unnecessarily expose information about the hardware state.
1893
1894 The vast majority of applications do not use these instructions.
1895 For the very few that do, software emulation is provided in
1896 specific cases in protected and virtual-8086 modes. Emulated
1897 results are dummy.
aa35f896 1898
72e9b5fe
DH
1899config X86_INTEL_MPX
1900 prompt "Intel MPX (Memory Protection Extensions)"
1901 def_bool n
df3735c5
RR
1902 # Note: only available in 64-bit mode due to VMA flags shortage
1903 depends on CPU_SUP_INTEL && X86_64
1904 select ARCH_USES_HIGH_VMA_FLAGS
72e9b5fe
DH
1905 ---help---
1906 MPX provides hardware features that can be used in
1907 conjunction with compiler-instrumented code to check
1908 memory references. It is designed to detect buffer
1909 overflow or underflow bugs.
1910
1911 This option enables running applications which are
1912 instrumented or otherwise use MPX. It does not use MPX
1913 itself inside the kernel or to protect the kernel
1914 against bad memory references.
1915
1916 Enabling this option will make the kernel larger:
1917 ~8k of kernel text and 36 bytes of data on a 64-bit
1918 defconfig. It adds a long to the 'mm_struct' which
1919 will increase the kernel memory overhead of each
1920 process and adds some branches to paths used during
1921 exec() and munmap().
1922
cb1aaebe 1923 For details, see Documentation/x86/intel_mpx.rst
72e9b5fe
DH
1924
1925 If unsure, say N.
1926
35e97790 1927config X86_INTEL_MEMORY_PROTECTION_KEYS
284244a9 1928 prompt "Intel Memory Protection Keys"
35e97790 1929 def_bool y
284244a9 1930 # Note: only available in 64-bit mode
35e97790 1931 depends on CPU_SUP_INTEL && X86_64
52c8e601
IM
1932 select ARCH_USES_HIGH_VMA_FLAGS
1933 select ARCH_HAS_PKEYS
284244a9
DH
1934 ---help---
1935 Memory Protection Keys provides a mechanism for enforcing
1936 page-based protections, but without requiring modification of the
1937 page tables when an application changes protection domains.
1938
1eecbcdc 1939 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1940
1941 If unsure, say y.
35e97790 1942
506f1d07 1943config EFI
9ba16087 1944 bool "EFI runtime service support"
5b83683f 1945 depends on ACPI
f6ce5002 1946 select UCS2_STRING
022ee6c5 1947 select EFI_RUNTIME_WRAPPERS
506f1d07 1948 ---help---
8f9ca475
IM
1949 This enables the kernel to use EFI runtime services that are
1950 available (such as the EFI variable services).
506f1d07 1951
8f9ca475
IM
1952 This option is only useful on systems that have EFI firmware.
1953 In addition, you should use the latest ELILO loader available
1954 at <http://elilo.sourceforge.net> in order to take advantage
1955 of EFI runtime services. However, even with this option, the
1956 resultant kernel should continue to boot on existing non-EFI
1957 platforms.
506f1d07 1958
291f3632
MF
1959config EFI_STUB
1960 bool "EFI stub support"
b16d8c23 1961 depends on EFI && !X86_USE_3DNOW
7b2a583a 1962 select RELOCATABLE
291f3632
MF
1963 ---help---
1964 This kernel feature allows a bzImage to be loaded directly
1965 by EFI firmware without the use of a bootloader.
1966
4f4cfa6c 1967 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1968
7d453eee
MF
1969config EFI_MIXED
1970 bool "EFI mixed-mode support"
1971 depends on EFI_STUB && X86_64
1972 ---help---
1973 Enabling this feature allows a 64-bit kernel to be booted
1974 on a 32-bit firmware, provided that your CPU supports 64-bit
1975 mode.
1976
1977 Note that it is not possible to boot a mixed-mode enabled
1978 kernel via the EFI boot stub - a bootloader that supports
1979 the EFI handover protocol must be used.
1980
1981 If unsure, say N.
1982
506f1d07 1983config SECCOMP
3c2362e6
HH
1984 def_bool y
1985 prompt "Enable seccomp to safely compute untrusted bytecode"
8f9ca475 1986 ---help---
506f1d07
SR
1987 This kernel feature is useful for number crunching applications
1988 that may need to compute untrusted bytecode during their
1989 execution. By using pipes or other transports made available to
1990 the process as file descriptors supporting the read/write
1991 syscalls, it's possible to isolate those applications in
1992 their own address space using seccomp. Once seccomp is
9c0bbee8 1993 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
506f1d07
SR
1994 and the task is only allowed to execute a few safe syscalls
1995 defined by each seccomp mode.
1996
1997 If unsure, say Y. Only embedded should say N here.
1998
8636a1f9 1999source "kernel/Kconfig.hz"
506f1d07
SR
2000
2001config KEXEC
2002 bool "kexec system call"
2965faa5 2003 select KEXEC_CORE
8f9ca475 2004 ---help---
506f1d07
SR
2005 kexec is a system call that implements the ability to shutdown your
2006 current kernel, and to start another kernel. It is like a reboot
2007 but it is independent of the system firmware. And like a reboot
2008 you can start any kernel with it, not just Linux.
2009
2010 The name comes from the similarity to the exec system call.
2011
2012 It is an ongoing process to be certain the hardware in a machine
2013 is properly shutdown, so do not be surprised if this code does not
bf220695
GU
2014 initially work for you. As of this writing the exact hardware
2015 interface is strongly in flux, so no good recommendation can be
2016 made.
506f1d07 2017
74ca317c
VG
2018config KEXEC_FILE
2019 bool "kexec file based system call"
2965faa5 2020 select KEXEC_CORE
74ca317c 2021 select BUILD_BIN2C
74ca317c
VG
2022 depends on X86_64
2023 depends on CRYPTO=y
2024 depends on CRYPTO_SHA256=y
2025 ---help---
2026 This is new version of kexec system call. This system call is
2027 file based and takes file descriptors as system call argument
2028 for kernel and initramfs as opposed to list of segments as
2029 accepted by previous system call.
2030
b799a09f
AT
2031config ARCH_HAS_KEXEC_PURGATORY
2032 def_bool KEXEC_FILE
2033
99d5cadf 2034config KEXEC_SIG
8e7d8381 2035 bool "Verify kernel signature during kexec_file_load() syscall"
74ca317c 2036 depends on KEXEC_FILE
8e7d8381 2037 ---help---
d8eb8940 2038
99d5cadf
JB
2039 This option makes the kexec_file_load() syscall check for a valid
2040 signature of the kernel image. The image can still be loaded without
2041 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2042 there's a signature that we can check, then it must be valid.
2043
2044 In addition to this option, you need to enable signature
d8eb8940
BP
2045 verification for the corresponding kernel image type being
2046 loaded in order for this to work.
8e7d8381 2047
99d5cadf
JB
2048config KEXEC_SIG_FORCE
2049 bool "Require a valid signature in kexec_file_load() syscall"
2050 depends on KEXEC_SIG
2051 ---help---
2052 This option makes kernel signature verification mandatory for
2053 the kexec_file_load() syscall.
2054
8e7d8381
VG
2055config KEXEC_BZIMAGE_VERIFY_SIG
2056 bool "Enable bzImage signature verification support"
99d5cadf 2057 depends on KEXEC_SIG
8e7d8381
VG
2058 depends on SIGNED_PE_FILE_VERIFICATION
2059 select SYSTEM_TRUSTED_KEYRING
2060 ---help---
2061 Enable bzImage signature verification support.
2062
506f1d07 2063config CRASH_DUMP
04b69447 2064 bool "kernel crash dumps"
506f1d07 2065 depends on X86_64 || (X86_32 && HIGHMEM)
8f9ca475 2066 ---help---
506f1d07
SR
2067 Generate crash dump after being started by kexec.
2068 This should be normally only set in special crash dump kernels
2069 which are loaded in the main kernel with kexec-tools into
2070 a specially reserved region and then later executed after
2071 a crash by kdump/kexec. The crash dump kernel must be compiled
2072 to a memory address not used by the main kernel or BIOS using
2073 PHYSICAL_START, or it must be built as a relocatable image
2074 (CONFIG_RELOCATABLE=y).
330d4810 2075 For more details see Documentation/admin-guide/kdump/kdump.rst
506f1d07 2076
3ab83521 2077config KEXEC_JUMP
6ea30386 2078 bool "kexec jump"
fee7b0d8 2079 depends on KEXEC && HIBERNATION
8f9ca475 2080 ---help---
89081d17
HY
2081 Jump between original kernel and kexeced kernel and invoke
2082 code in physical address mode via KEXEC
3ab83521 2083
506f1d07 2084config PHYSICAL_START
6a108a14 2085 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2086 default "0x1000000"
8f9ca475 2087 ---help---
506f1d07
SR
2088 This gives the physical address where the kernel is loaded.
2089
2090 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2091 bzImage will decompress itself to above physical address and
2092 run from there. Otherwise, bzImage will run from the address where
2093 it has been loaded by the boot loader and will ignore above physical
2094 address.
2095
2096 In normal kdump cases one does not have to set/change this option
2097 as now bzImage can be compiled as a completely relocatable image
2098 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2099 address. This option is mainly useful for the folks who don't want
2100 to use a bzImage for capturing the crash dump and want to use a
2101 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2102 to be specifically compiled to run from a specific memory area
2103 (normally a reserved region) and this option comes handy.
2104
ceefccc9
PA
2105 So if you are using bzImage for capturing the crash dump,
2106 leave the value here unchanged to 0x1000000 and set
2107 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2108 for capturing the crash dump change this value to start of
2109 the reserved region. In other words, it can be set based on
2110 the "X" value as specified in the "crashkernel=YM@XM"
2111 command line boot parameter passed to the panic-ed
330d4810 2112 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2113 for more details about crash dumps.
506f1d07
SR
2114
2115 Usage of bzImage for capturing the crash dump is recommended as
2116 one does not have to build two kernels. Same kernel can be used
2117 as production kernel and capture kernel. Above option should have
2118 gone away after relocatable bzImage support is introduced. But it
2119 is present because there are users out there who continue to use
2120 vmlinux for dump capture. This option should go away down the
2121 line.
2122
2123 Don't change this unless you know what you are doing.
2124
2125config RELOCATABLE
26717808
PA
2126 bool "Build a relocatable kernel"
2127 default y
8f9ca475 2128 ---help---
506f1d07
SR
2129 This builds a kernel image that retains relocation information
2130 so it can be loaded someplace besides the default 1MB.
2131 The relocations tend to make the kernel binary about 10% larger,
2132 but are discarded at runtime.
2133
2134 One use is for the kexec on panic case where the recovery kernel
2135 must live at a different physical address than the primary
2136 kernel.
2137
2138 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2139 it has been loaded at and the compile time physical address
8ab3820f 2140 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2141
8ab3820f 2142config RANDOMIZE_BASE
e8581e3d 2143 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2144 depends on RELOCATABLE
6807c846 2145 default y
8ab3820f 2146 ---help---
e8581e3d
BH
2147 In support of Kernel Address Space Layout Randomization (KASLR),
2148 this randomizes the physical address at which the kernel image
2149 is decompressed and the virtual address where the kernel
2150 image is mapped, as a security feature that deters exploit
2151 attempts relying on knowledge of the location of kernel
2152 code internals.
2153
ed9f007e
KC
2154 On 64-bit, the kernel physical and virtual addresses are
2155 randomized separately. The physical address will be anywhere
2156 between 16MB and the top of physical memory (up to 64TB). The
2157 virtual address will be randomized from 16MB up to 1GB (9 bits
2158 of entropy). Note that this also reduces the memory space
2159 available to kernel modules from 1.5GB to 1GB.
2160
2161 On 32-bit, the kernel physical and virtual addresses are
2162 randomized together. They will be randomized from 16MB up to
2163 512MB (8 bits of entropy).
e8581e3d
BH
2164
2165 Entropy is generated using the RDRAND instruction if it is
2166 supported. If RDTSC is supported, its value is mixed into
2167 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2168 supported, then entropy is read from the i8254 timer. The
2169 usable entropy is limited by the kernel being built using
2170 2GB addressing, and that PHYSICAL_ALIGN must be at a
2171 minimum of 2MB. As a result, only 10 bits of entropy are
2172 theoretically possible, but the implementations are further
2173 limited due to memory layouts.
e8581e3d 2174
6807c846 2175 If unsure, say Y.
8ab3820f
KC
2176
2177# Relocation on x86 needs some additional build support
845adf72
PA
2178config X86_NEED_RELOCS
2179 def_bool y
8ab3820f 2180 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2181
506f1d07 2182config PHYSICAL_ALIGN
a0215061 2183 hex "Alignment value to which kernel should be aligned"
8ab3820f 2184 default "0x200000"
a0215061
KC
2185 range 0x2000 0x1000000 if X86_32
2186 range 0x200000 0x1000000 if X86_64
8f9ca475 2187 ---help---
506f1d07
SR
2188 This value puts the alignment restrictions on physical address
2189 where kernel is loaded and run from. Kernel is compiled for an
2190 address which meets above alignment restriction.
2191
2192 If bootloader loads the kernel at a non-aligned address and
2193 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2194 address aligned to above value and run from there.
2195
2196 If bootloader loads the kernel at a non-aligned address and
2197 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2198 load address and decompress itself to the address it has been
2199 compiled for and run from there. The address for which kernel is
2200 compiled already meets above alignment restrictions. Hence the
2201 end result is that kernel runs from a physical address meeting
2202 above alignment restrictions.
2203
a0215061
KC
2204 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2205 this value must be a multiple of 0x200000.
2206
506f1d07
SR
2207 Don't change this unless you know what you are doing.
2208
eedb92ab
KS
2209config DYNAMIC_MEMORY_LAYOUT
2210 bool
2211 ---help---
2212 This option makes base addresses of vmalloc and vmemmap as well as
2213 __PAGE_OFFSET movable during boot.
2214
0483e1fa
TG
2215config RANDOMIZE_MEMORY
2216 bool "Randomize the kernel memory sections"
2217 depends on X86_64
2218 depends on RANDOMIZE_BASE
eedb92ab 2219 select DYNAMIC_MEMORY_LAYOUT
0483e1fa
TG
2220 default RANDOMIZE_BASE
2221 ---help---
2222 Randomizes the base virtual address of kernel memory sections
2223 (physical memory mapping, vmalloc & vmemmap). This security feature
2224 makes exploits relying on predictable memory locations less reliable.
2225
2226 The order of allocations remains unchanged. Entropy is generated in
2227 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2228 configuration have in average 30,000 different possible virtual
2229 addresses for each memory section.
2230
6807c846 2231 If unsure, say Y.
0483e1fa 2232
90397a41
TG
2233config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2234 hex "Physical memory mapping padding" if EXPERT
2235 depends on RANDOMIZE_MEMORY
2236 default "0xa" if MEMORY_HOTPLUG
2237 default "0x0"
2238 range 0x1 0x40 if MEMORY_HOTPLUG
2239 range 0x0 0x40
2240 ---help---
2241 Define the padding in terabytes added to the existing physical
2242 memory size during kernel memory randomization. It is useful
2243 for memory hotplug support but reduces the entropy available for
2244 address randomization.
2245
2246 If unsure, leave at the default value.
2247
506f1d07 2248config HOTPLUG_CPU
bebd024e 2249 def_bool y
40b31360 2250 depends on SMP
506f1d07 2251
80aa1dff
FY
2252config BOOTPARAM_HOTPLUG_CPU0
2253 bool "Set default setting of cpu0_hotpluggable"
2c922cd0 2254 depends on HOTPLUG_CPU
80aa1dff
FY
2255 ---help---
2256 Set whether default state of cpu0_hotpluggable is on or off.
2257
2258 Say Y here to enable CPU0 hotplug by default. If this switch
2259 is turned on, there is no need to give cpu0_hotplug kernel
2260 parameter and the CPU0 hotplug feature is enabled by default.
2261
2262 Please note: there are two known CPU0 dependencies if you want
2263 to enable the CPU0 hotplug feature either by this switch or by
2264 cpu0_hotplug kernel parameter.
2265
2266 First, resume from hibernate or suspend always starts from CPU0.
2267 So hibernate and suspend are prevented if CPU0 is offline.
2268
2269 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2270 offline if any interrupt can not migrate out of CPU0. There may
2271 be other CPU0 dependencies.
2272
2273 Please make sure the dependencies are under your control before
2274 you enable this feature.
2275
2276 Say N if you don't want to enable CPU0 hotplug feature by default.
2277 You still can enable the CPU0 hotplug feature at boot by kernel
2278 parameter cpu0_hotplug.
2279
a71c8bc5
FY
2280config DEBUG_HOTPLUG_CPU0
2281 def_bool n
2282 prompt "Debug CPU0 hotplug"
2c922cd0 2283 depends on HOTPLUG_CPU
a71c8bc5
FY
2284 ---help---
2285 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2286 soon as possible and boots up userspace with CPU0 offlined. User
2287 can online CPU0 back after boot time.
2288
2289 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2290 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2291 compilation or giving cpu0_hotplug kernel parameter at boot.
2292
2293 If unsure, say N.
2294
506f1d07 2295config COMPAT_VDSO
b0b49f26
AL
2296 def_bool n
2297 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2298 depends on COMPAT_32
8f9ca475 2299 ---help---
b0b49f26
AL
2300 Certain buggy versions of glibc will crash if they are
2301 presented with a 32-bit vDSO that is not mapped at the address
2302 indicated in its segment table.
e84446de 2303
b0b49f26
AL
2304 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2305 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2306 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2307 the only released version with the bug, but OpenSUSE 9
2308 contains a buggy "glibc 2.3.2".
506f1d07 2309
b0b49f26
AL
2310 The symptom of the bug is that everything crashes on startup, saying:
2311 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2312
2313 Saying Y here changes the default value of the vdso32 boot
2314 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2315 This works around the glibc bug but hurts performance.
2316
2317 If unsure, say N: if you are compiling your own kernel, you
2318 are unlikely to be using a buggy version of glibc.
506f1d07 2319
3dc33bd3
KC
2320choice
2321 prompt "vsyscall table for legacy applications"
2322 depends on X86_64
625b7b7f 2323 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2324 help
2325 Legacy user code that does not know how to find the vDSO expects
2326 to be able to issue three syscalls by calling fixed addresses in
2327 kernel space. Since this location is not randomized with ASLR,
2328 it can be used to assist security vulnerability exploitation.
2329
2330 This setting can be changed at boot time via the kernel command
bd49e16e 2331 line parameter vsyscall=[emulate|xonly|none].
3dc33bd3
KC
2332
2333 On a system with recent enough glibc (2.14 or newer) and no
2334 static binaries, you can say None without a performance penalty
2335 to improve security.
2336
bd49e16e 2337 If unsure, select "Emulate execution only".
3dc33bd3 2338
3dc33bd3 2339 config LEGACY_VSYSCALL_EMULATE
bd49e16e 2340 bool "Full emulation"
3dc33bd3 2341 help
bd49e16e
AL
2342 The kernel traps and emulates calls into the fixed vsyscall
2343 address mapping. This makes the mapping non-executable, but
2344 it still contains readable known contents, which could be
2345 used in certain rare security vulnerability exploits. This
2346 configuration is recommended when using legacy userspace
2347 that still uses vsyscalls along with legacy binary
2348 instrumentation tools that require code to be readable.
2349
2350 An example of this type of legacy userspace is running
2351 Pin on an old binary that still uses vsyscalls.
2352
2353 config LEGACY_VSYSCALL_XONLY
2354 bool "Emulate execution only"
2355 help
2356 The kernel traps and emulates calls into the fixed vsyscall
2357 address mapping and does not allow reads. This
2358 configuration is recommended when userspace might use the
2359 legacy vsyscall area but support for legacy binary
2360 instrumentation of legacy code is not needed. It mitigates
2361 certain uses of the vsyscall area as an ASLR-bypassing
2362 buffer.
3dc33bd3
KC
2363
2364 config LEGACY_VSYSCALL_NONE
2365 bool "None"
2366 help
2367 There will be no vsyscall mapping at all. This will
2368 eliminate any risk of ASLR bypass due to the vsyscall
2369 fixed address mapping. Attempts to use the vsyscalls
2370 will be reported to dmesg, so that either old or
2371 malicious userspace programs can be identified.
2372
2373endchoice
2374
516cbf37
TB
2375config CMDLINE_BOOL
2376 bool "Built-in kernel command line"
8f9ca475 2377 ---help---
516cbf37
TB
2378 Allow for specifying boot arguments to the kernel at
2379 build time. On some systems (e.g. embedded ones), it is
2380 necessary or convenient to provide some or all of the
2381 kernel boot arguments with the kernel itself (that is,
2382 to not rely on the boot loader to provide them.)
2383
2384 To compile command line arguments into the kernel,
2385 set this option to 'Y', then fill in the
69711ca1 2386 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2387
2388 Systems with fully functional boot loaders (i.e. non-embedded)
2389 should leave this option set to 'N'.
2390
2391config CMDLINE
2392 string "Built-in kernel command string"
2393 depends on CMDLINE_BOOL
2394 default ""
8f9ca475 2395 ---help---
516cbf37
TB
2396 Enter arguments here that should be compiled into the kernel
2397 image and used at boot time. If the boot loader provides a
2398 command line at boot time, it is appended to this string to
2399 form the full kernel command line, when the system boots.
2400
2401 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2402 change this behavior.
2403
2404 In most cases, the command line (whether built-in or provided
2405 by the boot loader) should specify the device for the root
2406 file system.
2407
2408config CMDLINE_OVERRIDE
2409 bool "Built-in command line overrides boot loader arguments"
516cbf37 2410 depends on CMDLINE_BOOL
8f9ca475 2411 ---help---
516cbf37
TB
2412 Set this option to 'Y' to have the kernel ignore the boot loader
2413 command line, and use ONLY the built-in command line.
2414
2415 This is used to work around broken boot loaders. This should
2416 be set to 'N' under normal conditions.
2417
a5b9e5a2
AL
2418config MODIFY_LDT_SYSCALL
2419 bool "Enable the LDT (local descriptor table)" if EXPERT
2420 default y
2421 ---help---
2422 Linux can allow user programs to install a per-process x86
2423 Local Descriptor Table (LDT) using the modify_ldt(2) system
2424 call. This is required to run 16-bit or segmented code such as
2425 DOSEMU or some Wine programs. It is also used by some very old
2426 threading libraries.
2427
2428 Enabling this feature adds a small amount of overhead to
2429 context switches and increases the low-level kernel attack
2430 surface. Disabling it removes the modify_ldt(2) system call.
2431
2432 Saying 'N' here may make sense for embedded or server kernels.
2433
b700e7f0
SJ
2434source "kernel/livepatch/Kconfig"
2435
506f1d07
SR
2436endmenu
2437
3072e413
MH
2438config ARCH_HAS_ADD_PAGES
2439 def_bool y
2440 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2441
506f1d07
SR
2442config ARCH_ENABLE_MEMORY_HOTPLUG
2443 def_bool y
2444 depends on X86_64 || (X86_32 && HIGHMEM)
2445
35551053
GH
2446config ARCH_ENABLE_MEMORY_HOTREMOVE
2447 def_bool y
2448 depends on MEMORY_HOTPLUG
2449
e534c7c5 2450config USE_PERCPU_NUMA_NODE_ID
645a7919 2451 def_bool y
e534c7c5
LS
2452 depends on NUMA
2453
9491846f
KS
2454config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2455 def_bool y
2456 depends on X86_64 || X86_PAE
2457
c177c81e
NH
2458config ARCH_ENABLE_HUGEPAGE_MIGRATION
2459 def_bool y
2460 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2461
9c670ea3
NH
2462config ARCH_ENABLE_THP_MIGRATION
2463 def_bool y
2464 depends on X86_64 && TRANSPARENT_HUGEPAGE
2465
da85f865 2466menu "Power management and ACPI options"
e279b6c1
SR
2467
2468config ARCH_HIBERNATION_HEADER
3c2362e6 2469 def_bool y
44556530 2470 depends on HIBERNATION
e279b6c1
SR
2471
2472source "kernel/power/Kconfig"
2473
2474source "drivers/acpi/Kconfig"
2475
efafc8b2
FT
2476source "drivers/sfi/Kconfig"
2477
a6b68076 2478config X86_APM_BOOT
6fc108a0 2479 def_bool y
282e5aab 2480 depends on APM
a6b68076 2481
e279b6c1
SR
2482menuconfig APM
2483 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2484 depends on X86_32 && PM_SLEEP
e279b6c1
SR
2485 ---help---
2486 APM is a BIOS specification for saving power using several different
2487 techniques. This is mostly useful for battery powered laptops with
2488 APM compliant BIOSes. If you say Y here, the system time will be
2489 reset after a RESUME operation, the /proc/apm device will provide
2490 battery status information, and user-space programs will receive
2491 notification of APM "events" (e.g. battery status change).
2492
2493 If you select "Y" here, you can disable actual use of the APM
2494 BIOS by passing the "apm=off" option to the kernel at boot time.
2495
2496 Note that the APM support is almost completely disabled for
2497 machines with more than one CPU.
2498
2499 In order to use APM, you will need supporting software. For location
151f4e2b 2500 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2501 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2502 <http://www.tldp.org/docs.html#howto>.
2503
2504 This driver does not spin down disk drives (see the hdparm(8)
2505 manpage ("man 8 hdparm") for that), and it doesn't turn off
2506 VESA-compliant "green" monitors.
2507
2508 This driver does not support the TI 4000M TravelMate and the ACER
2509 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2510 desktop machines also don't have compliant BIOSes, and this driver
2511 may cause those machines to panic during the boot phase.
2512
2513 Generally, if you don't have a battery in your machine, there isn't
2514 much point in using this driver and you should say N. If you get
2515 random kernel OOPSes or reboots that don't seem to be related to
2516 anything, try disabling/enabling this option (or disabling/enabling
2517 APM in your BIOS).
2518
2519 Some other things you should try when experiencing seemingly random,
2520 "weird" problems:
2521
2522 1) make sure that you have enough swap space and that it is
2523 enabled.
2524 2) pass the "no-hlt" option to the kernel
2525 3) switch on floating point emulation in the kernel and pass
2526 the "no387" option to the kernel
2527 4) pass the "floppy=nodma" option to the kernel
2528 5) pass the "mem=4M" option to the kernel (thereby disabling
2529 all but the first 4 MB of RAM)
2530 6) make sure that the CPU is not over clocked.
2531 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2532 8) disable the cache from your BIOS settings
2533 9) install a fan for the video card or exchange video RAM
2534 10) install a better fan for the CPU
2535 11) exchange RAM chips
2536 12) exchange the motherboard.
2537
2538 To compile this driver as a module, choose M here: the
2539 module will be called apm.
2540
2541if APM
2542
2543config APM_IGNORE_USER_SUSPEND
2544 bool "Ignore USER SUSPEND"
8f9ca475 2545 ---help---
e279b6c1
SR
2546 This option will ignore USER SUSPEND requests. On machines with a
2547 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2548 series notebooks, it is necessary to say Y because of a BIOS bug.
2549
2550config APM_DO_ENABLE
2551 bool "Enable PM at boot time"
2552 ---help---
2553 Enable APM features at boot time. From page 36 of the APM BIOS
2554 specification: "When disabled, the APM BIOS does not automatically
2555 power manage devices, enter the Standby State, enter the Suspend
2556 State, or take power saving steps in response to CPU Idle calls."
2557 This driver will make CPU Idle calls when Linux is idle (unless this
2558 feature is turned off -- see "Do CPU IDLE calls", below). This
2559 should always save battery power, but more complicated APM features
2560 will be dependent on your BIOS implementation. You may need to turn
2561 this option off if your computer hangs at boot time when using APM
2562 support, or if it beeps continuously instead of suspending. Turn
2563 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2564 T400CDT. This is off by default since most machines do fine without
2565 this feature.
2566
2567config APM_CPU_IDLE
dd8af076 2568 depends on CPU_IDLE
e279b6c1 2569 bool "Make CPU Idle calls when idle"
8f9ca475 2570 ---help---
e279b6c1
SR
2571 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2572 On some machines, this can activate improved power savings, such as
2573 a slowed CPU clock rate, when the machine is idle. These idle calls
2574 are made after the idle loop has run for some length of time (e.g.,
2575 333 mS). On some machines, this will cause a hang at boot time or
2576 whenever the CPU becomes idle. (On machines with more than one CPU,
2577 this option does nothing.)
2578
2579config APM_DISPLAY_BLANK
2580 bool "Enable console blanking using APM"
8f9ca475 2581 ---help---
e279b6c1
SR
2582 Enable console blanking using the APM. Some laptops can use this to
2583 turn off the LCD backlight when the screen blanker of the Linux
2584 virtual console blanks the screen. Note that this is only used by
2585 the virtual console screen blanker, and won't turn off the backlight
2586 when using the X Window system. This also doesn't have anything to
2587 do with your VESA-compliant power-saving monitor. Further, this
2588 option doesn't work for all laptops -- it might not turn off your
2589 backlight at all, or it might print a lot of errors to the console,
2590 especially if you are using gpm.
2591
2592config APM_ALLOW_INTS
2593 bool "Allow interrupts during APM BIOS calls"
8f9ca475 2594 ---help---
e279b6c1
SR
2595 Normally we disable external interrupts while we are making calls to
2596 the APM BIOS as a measure to lessen the effects of a badly behaving
2597 BIOS implementation. The BIOS should reenable interrupts if it
2598 needs to. Unfortunately, some BIOSes do not -- especially those in
2599 many of the newer IBM Thinkpads. If you experience hangs when you
2600 suspend, try setting this to Y. Otherwise, say N.
2601
e279b6c1
SR
2602endif # APM
2603
bb0a56ec 2604source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2605
2606source "drivers/cpuidle/Kconfig"
2607
27471fdb
AH
2608source "drivers/idle/Kconfig"
2609
e279b6c1
SR
2610endmenu
2611
2612
2613menu "Bus options (PCI etc.)"
2614
e279b6c1
SR
2615choice
2616 prompt "PCI access mode"
efefa6f6 2617 depends on X86_32 && PCI
e279b6c1
SR
2618 default PCI_GOANY
2619 ---help---
2620 On PCI systems, the BIOS can be used to detect the PCI devices and
2621 determine their configuration. However, some old PCI motherboards
2622 have BIOS bugs and may crash if this is done. Also, some embedded
2623 PCI-based systems don't have any BIOS at all. Linux can also try to
2624 detect the PCI hardware directly without using the BIOS.
2625
2626 With this option, you can specify how Linux should detect the
2627 PCI devices. If you choose "BIOS", the BIOS will be used,
2628 if you choose "Direct", the BIOS won't be used, and if you
2629 choose "MMConfig", then PCI Express MMCONFIG will be used.
2630 If you choose "Any", the kernel will try MMCONFIG, then the
2631 direct access method and falls back to the BIOS if that doesn't
2632 work. If unsure, go with the default, which is "Any".
2633
2634config PCI_GOBIOS
2635 bool "BIOS"
2636
2637config PCI_GOMMCONFIG
2638 bool "MMConfig"
2639
2640config PCI_GODIRECT
2641 bool "Direct"
2642
3ef0e1f8 2643config PCI_GOOLPC
76fb6570 2644 bool "OLPC XO-1"
3ef0e1f8
AS
2645 depends on OLPC
2646
2bdd1b03
AS
2647config PCI_GOANY
2648 bool "Any"
2649
e279b6c1
SR
2650endchoice
2651
2652config PCI_BIOS
3c2362e6 2653 def_bool y
efefa6f6 2654 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2655
2656# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2657config PCI_DIRECT
3c2362e6 2658 def_bool y
0aba496f 2659 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2660
2661config PCI_MMCONFIG
b45c9f36
JK
2662 bool "Support mmconfig PCI config space access" if X86_64
2663 default y
8364e1f8 2664 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
b45c9f36 2665 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2666
3ef0e1f8 2667config PCI_OLPC
2bdd1b03
AS
2668 def_bool y
2669 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2670
b5401a96
AN
2671config PCI_XEN
2672 def_bool y
2673 depends on PCI && XEN
2674 select SWIOTLB_XEN
2675
8364e1f8
JK
2676config MMCONF_FAM10H
2677 def_bool y
2678 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2679
3f6ea84a 2680config PCI_CNB20LE_QUIRK
6a108a14 2681 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2682 depends on PCI
3f6ea84a
IS
2683 help
2684 Read the PCI windows out of the CNB20LE host bridge. This allows
2685 PCI hotplug to work on systems with the CNB20LE chipset which do
2686 not have ACPI.
2687
64a5fed6
BH
2688 There's no public spec for this chipset, and this functionality
2689 is known to be incomplete.
2690
2691 You should say N unless you know you need this.
2692
3a495511 2693config ISA_BUS
17a2a129 2694 bool "ISA bus support on modern systems" if EXPERT
3a495511 2695 help
17a2a129
WBG
2696 Expose ISA bus device drivers and options available for selection and
2697 configuration. Enable this option if your target machine has an ISA
2698 bus. ISA is an older system, displaced by PCI and newer bus
2699 architectures -- if your target machine is modern, it probably does
2700 not have an ISA bus.
3a495511
WBG
2701
2702 If unsure, say N.
2703
1c00f016 2704# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2705config ISA_DMA_API
1c00f016
DR
2706 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2707 default y
2708 help
2709 Enables ISA-style DMA support for devices requiring such controllers.
2710 If unsure, say Y.
e279b6c1 2711
51e68d05
LT
2712if X86_32
2713
e279b6c1
SR
2714config ISA
2715 bool "ISA support"
8f9ca475 2716 ---help---
e279b6c1
SR
2717 Find out whether you have ISA slots on your motherboard. ISA is the
2718 name of a bus system, i.e. the way the CPU talks to the other stuff
2719 inside your box. Other bus systems are PCI, EISA, MicroChannel
2720 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2721 newer boards don't support it. If you have ISA, say Y, otherwise N.
2722
e279b6c1
SR
2723config SCx200
2724 tristate "NatSemi SCx200 support"
8f9ca475 2725 ---help---
e279b6c1
SR
2726 This provides basic support for National Semiconductor's
2727 (now AMD's) Geode processors. The driver probes for the
2728 PCI-IDs of several on-chip devices, so its a good dependency
2729 for other scx200_* drivers.
2730
2731 If compiled as a module, the driver is named scx200.
2732
2733config SCx200HR_TIMER
2734 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2735 depends on SCx200
e279b6c1 2736 default y
8f9ca475 2737 ---help---
e279b6c1
SR
2738 This driver provides a clocksource built upon the on-chip
2739 27MHz high-resolution timer. Its also a workaround for
2740 NSC Geode SC-1100's buggy TSC, which loses time when the
2741 processor goes idle (as is done by the scheduler). The
2742 other workaround is idle=poll boot option.
2743
3ef0e1f8
AS
2744config OLPC
2745 bool "One Laptop Per Child support"
54008979 2746 depends on !X86_PAE
3c554946 2747 select GPIOLIB
dc3119e7 2748 select OF
45bb1674 2749 select OF_PROMTREE
b4e51854 2750 select IRQ_DOMAIN
0c3d931b 2751 select OLPC_EC
8f9ca475 2752 ---help---
3ef0e1f8
AS
2753 Add support for detecting the unique features of the OLPC
2754 XO hardware.
2755
a3128588
DD
2756config OLPC_XO1_PM
2757 bool "OLPC XO-1 Power Management"
fa112cf1 2758 depends on OLPC && MFD_CS5535=y && PM_SLEEP
bf1ebf00 2759 ---help---
97c4cb71 2760 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2761
cfee9597
DD
2762config OLPC_XO1_RTC
2763 bool "OLPC XO-1 Real Time Clock"
2764 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2765 ---help---
2766 Add support for the XO-1 real time clock, which can be used as a
2767 programmable wakeup source.
2768
7feda8e9
DD
2769config OLPC_XO1_SCI
2770 bool "OLPC XO-1 SCI extras"
92e830f2 2771 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2772 depends on INPUT=y
d8d01a63 2773 select POWER_SUPPLY
7feda8e9
DD
2774 ---help---
2775 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2776 - EC-driven system wakeups
7feda8e9 2777 - Power button
7bc74b3d 2778 - Ebook switch
2cf2baea 2779 - Lid switch
e1040ac6
DD
2780 - AC adapter status updates
2781 - Battery status updates
7feda8e9 2782
a0f30f59
DD
2783config OLPC_XO15_SCI
2784 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2785 depends on OLPC && ACPI
2786 select POWER_SUPPLY
a0f30f59
DD
2787 ---help---
2788 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2789 - EC-driven system wakeups
2790 - AC adapter status updates
2791 - Battery status updates
bf1ebf00 2792
d4f3e350
EW
2793config ALIX
2794 bool "PCEngines ALIX System Support (LED setup)"
2795 select GPIOLIB
2796 ---help---
2797 This option enables system support for the PCEngines ALIX.
2798 At present this just sets up LEDs for GPIO control on
2799 ALIX2/3/6 boards. However, other system specific setup should
2800 get added here.
2801
2802 Note: You must still enable the drivers for GPIO and LED support
2803 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2804
2805 Note: You have to set alix.force=1 for boards with Award BIOS.
2806
da4e3302
PP
2807config NET5501
2808 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2809 select GPIOLIB
2810 ---help---
2811 This option enables system support for the Soekris Engineering net5501.
2812
3197059a
PP
2813config GEOS
2814 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2815 select GPIOLIB
2816 depends on DMI
2817 ---help---
2818 This option enables system support for the Traverse Technologies GEOS.
2819
7d029125
VD
2820config TS5500
2821 bool "Technologic Systems TS-5500 platform support"
2822 depends on MELAN
2823 select CHECK_SIGNATURE
2824 select NEW_LEDS
2825 select LEDS_CLASS
2826 ---help---
2827 This option enables system support for the Technologic Systems TS-5500.
2828
bc0120fd
SR
2829endif # X86_32
2830
23ac4ae8 2831config AMD_NB
e279b6c1 2832 def_bool y
0e152cd7 2833 depends on CPU_SUP_AMD && PCI
e279b6c1 2834
e3263ab3
DH
2835config X86_SYSFB
2836 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2837 help
2838 Firmwares often provide initial graphics framebuffers so the BIOS,
2839 bootloader or kernel can show basic video-output during boot for
2840 user-guidance and debugging. Historically, x86 used the VESA BIOS
2841 Extensions and EFI-framebuffers for this, which are mostly limited
2842 to x86.
2843 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2844 framebuffers so the new generic system-framebuffer drivers can be
2845 used on x86. If the framebuffer is not compatible with the generic
e3a5dc08 2846 modes, it is advertised as fallback platform framebuffer so legacy
e3263ab3
DH
2847 drivers like efifb, vesafb and uvesafb can pick it up.
2848 If this option is not selected, all system framebuffers are always
2849 marked as fallback platform framebuffers as usual.
2850
2851 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2852 not be able to pick up generic system framebuffers if this option
2853 is selected. You are highly encouraged to enable simplefb as
2854 replacement if you select this option. simplefb can correctly deal
2855 with generic system framebuffers. But you should still keep vesafb
2856 and others enabled as fallback if a system framebuffer is
2857 incompatible with simplefb.
2858
2859 If unsure, say Y.
2860
e279b6c1
SR
2861endmenu
2862
2863
1572497c 2864menu "Binary Emulations"
e279b6c1
SR
2865
2866config IA32_EMULATION
2867 bool "IA32 Emulation"
2868 depends on X86_64
39f88911 2869 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2870 select BINFMT_ELF
a97f52e6 2871 select COMPAT_BINFMT_ELF
39f88911 2872 select COMPAT_OLD_SIGACTION
8f9ca475 2873 ---help---
5fd92e65
L
2874 Include code to run legacy 32-bit programs under a
2875 64-bit kernel. You should likely turn this on, unless you're
2876 100% sure that you don't have any 32-bit programs left.
e279b6c1
SR
2877
2878config IA32_AOUT
8f9ca475
IM
2879 tristate "IA32 a.out support"
2880 depends on IA32_EMULATION
eac61655 2881 depends on BROKEN
8f9ca475
IM
2882 ---help---
2883 Support old a.out binaries in the 32bit emulation.
e279b6c1 2884
0bf62763 2885config X86_X32
6ea30386 2886 bool "x32 ABI for 64-bit mode"
9b54050b 2887 depends on X86_64
5fd92e65
L
2888 ---help---
2889 Include code to run binaries for the x32 native 32-bit ABI
2890 for 64-bit processors. An x32 process gets access to the
2891 full 64-bit register file and wide data path while leaving
2892 pointers at 32 bits for smaller memory footprint.
2893
2894 You will need a recent binutils (2.22 or later) with
2895 elf32_x86_64 support enabled to compile a kernel with this
2896 option set.
2897
953fee1d
IM
2898config COMPAT_32
2899 def_bool y
2900 depends on IA32_EMULATION || X86_32
2901 select HAVE_UID16
2902 select OLD_SIGSUSPEND3
2903
e279b6c1 2904config COMPAT
3c2362e6 2905 def_bool y
0bf62763 2906 depends on IA32_EMULATION || X86_X32
e279b6c1 2907
3120e25e 2908if COMPAT
e279b6c1 2909config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2910 def_bool y
e279b6c1
SR
2911
2912config SYSVIPC_COMPAT
3c2362e6 2913 def_bool y
3120e25e 2914 depends on SYSVIPC
3120e25e 2915endif
ee009e4a 2916
e279b6c1
SR
2917endmenu
2918
2919
e5beae16
KP
2920config HAVE_ATOMIC_IOMAP
2921 def_bool y
2922 depends on X86_32
2923
4692d77f
AR
2924config X86_DEV_DMA_OPS
2925 bool
f7219a53 2926
e279b6c1
SR
2927source "drivers/firmware/Kconfig"
2928
edf88417 2929source "arch/x86/kvm/Kconfig"