Merge tag 'for-v6.8-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux...
[linux-2.6-block.git] / arch / x86 / Kconfig
CommitLineData
b2441318 1# SPDX-License-Identifier: GPL-2.0
daa93fab
SR
2# Select 32 or 64 bit
3config 64BIT
104daea1
MY
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
a7f7f624 6 help
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SR
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
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JB
11 def_bool y
12 depends on !64BIT
341c787e
IM
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
15 select CLKSRC_I8253
16 select CLONE_BACKWARDS
157e118b 17 select GENERIC_VDSO_32
117ed454 18 select HAVE_DEBUG_STACKOVERFLOW
157e118b 19 select KMAP_LOCAL
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IM
20 select MODULES_USE_ELF_REL
21 select OLD_SIGACTION
2ca408d9 22 select ARCH_SPLIT_ARG64
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SR
23
24config X86_64
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JB
25 def_bool y
26 depends on 64BIT
d94e0685 27 # Options that are inherently 64-bit kernel only:
4eb0716e 28 select ARCH_HAS_GIGANTIC_PAGE
c12d3362 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
0bff0aae 30 select ARCH_SUPPORTS_PER_VMA_LOCK
d94e0685
IM
31 select HAVE_ARCH_SOFT_DIRTY
32 select MODULES_USE_ELF_RELA
f616ab59 33 select NEED_DMA_MAP_STATE
09230cbc 34 select SWIOTLB
7facdc42 35 select ARCH_HAS_ELFCORE_COMPAT
63703f37 36 select ZONE_DMA32
1032c0ba 37
518049d9
SRV
38config FORCE_DYNAMIC_FTRACE
39 def_bool y
40 depends on X86_32
41 depends on FUNCTION_TRACER
42 select DYNAMIC_FTRACE
43 help
758cd94a
JH
44 We keep the static function tracing (!DYNAMIC_FTRACE) around
45 in order to test the non static function tracing in the
46 generic code, as other architectures still use it. But we
47 only need to keep it around for x86_64. No need to keep it
48 for x86_32. For x86_32, force DYNAMIC_FTRACE.
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IM
49#
50# Arch settings
51#
52# ( Note that options that are marked 'if X86_64' could in principle be
53# ported to 32-bit as well. )
54#
8d5fffb9 55config X86
3c2362e6 56 def_bool y
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IM
57 #
58 # Note: keep this list sorted alphabetically
59 #
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IM
60 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
61 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
a02f66bb 62 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU
942fa985 63 select ARCH_32BIT_OFF_T if X86_32
2a21ad57 64 select ARCH_CLOCKSOURCE_INIT
1f6d3a8f 65 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
1e866974 66 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
5c11f00b 67 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
91024b3c 68 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
cebc774f 69 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
1e866974 70 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
c763ea26 71 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
c2280be8 72 select ARCH_HAS_CACHE_LINE_SIZE
1156b441 73 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
7c7077a7 74 select ARCH_HAS_CPU_FINALIZE_INIT
8f23f5db 75 select ARCH_HAS_CPU_PASID if IOMMU_SVA
2792d84e 76 select ARCH_HAS_CURRENT_STACK_POINTER
fa5b6ec9 77 select ARCH_HAS_DEBUG_VIRTUAL
399145f9 78 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
21266be9 79 select ARCH_HAS_DEVMEM_IS_ALLOWED
b1a57bbf 80 select ARCH_HAS_EARLY_DEBUG if KGDB
6471b825 81 select ARCH_HAS_ELF_RANDOMIZE
72d93104 82 select ARCH_HAS_FAST_MULTIPLIER
6974f0c4 83 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 84 select ARCH_HAS_GCOV_PROFILE_ALL
bece04b5 85 select ARCH_HAS_KCOV if X86_64
0c9c1d56 86 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 87 select ARCH_HAS_MEMBARRIER_SYNC_CORE
49f88c70 88 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
0ebeea8c 89 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
c763ea26 90 select ARCH_HAS_PMEM_API if X86_64
17596731 91 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 92 select ARCH_HAS_PTE_SPECIAL
71ce1ab5 93 select ARCH_HAS_HW_PTE_YOUNG
eed9a328 94 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2
0aed55af 95 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
ec6347bb 96 select ARCH_HAS_COPY_MC if X86_64
d2852a22 97 select ARCH_HAS_SET_MEMORY
d253ca0c 98 select ARCH_HAS_SET_DIRECT_MAP
ad21fc4f
LA
99 select ARCH_HAS_STRICT_KERNEL_RWX
100 select ARCH_HAS_STRICT_MODULE_RWX
ac1ab12a 101 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
25c619e5 102 select ARCH_HAS_SYSCALL_WRAPPER
c6d30853 103 select ARCH_HAS_UBSAN_SANITIZE_ALL
7e01ccb4 104 select ARCH_HAS_DEBUG_WX
63703f37 105 select ARCH_HAS_ZONE_DMA_SET if EXPERT
6471b825 106 select ARCH_HAVE_NMI_SAFE_CMPXCHG
04d5ea46 107 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
6471b825 108 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 109 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 110 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 111 select ARCH_STACKWALK
2c870e61 112 select ARCH_SUPPORTS_ACPI
6471b825 113 select ARCH_SUPPORTS_ATOMIC_RMW
5d6ad668 114 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
d283d422 115 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64
6471b825 116 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
14df3267 117 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096
3c516f89
ST
118 select ARCH_SUPPORTS_CFI_CLANG if X86_64
119 select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG
583bfd48
NC
120 select ARCH_SUPPORTS_LTO_CLANG
121 select ARCH_SUPPORTS_LTO_CLANG_THIN
6471b825 122 select ARCH_USE_BUILTIN_BSWAP
a432b7c0 123 select ARCH_USE_CMPXCHG_LOCKREF if X86_CMPXCHG64
dce44566 124 select ARCH_USE_MEMTEST
6471b825
IM
125 select ARCH_USE_QUEUED_RWLOCKS
126 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 127 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 128 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 129 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 130 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
51c2ee6d 131 select ARCH_WANTS_NO_INSTR
07431506 132 select ARCH_WANT_GENERAL_HUGETLB
3876d4a3 133 select ARCH_WANT_HUGE_PMD_SHARE
59612b24 134 select ARCH_WANT_LD_ORPHAN_WARN
0b6f1582
AK
135 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64
136 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64
38d8b4e6 137 select ARCH_WANTS_THP_SWAP if X86_64
b5f06f64 138 select ARCH_HAS_PARANOID_L1D_FLUSH
10916706 139 select BUILDTIME_TABLE_SORT
6471b825 140 select CLKEVT_I8253
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IM
141 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
142 select CLOCKSOURCE_WATCHDOG
7cf8f44a
AP
143 # Word-size accesses may read uninitialized data past the trailing \0
144 # in strings and cause false KMSAN reports.
145 select DCACHE_WORD_ACCESS if !KMSAN
3aac3ebe 146 select DYNAMIC_SIGFRAME
45471cd9
LT
147 select EDAC_ATOMIC_SCRUB
148 select EDAC_SUPPORT
6471b825
IM
149 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
150 select GENERIC_CLOCKEVENTS_MIN_ADJUST
151 select GENERIC_CMOS_UPDATE
152 select GENERIC_CPU_AUTOPROBE
5b95f94c 153 select GENERIC_CPU_DEVICES
61dc0f55 154 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 155 select GENERIC_EARLY_IOREMAP
27d6b4d1 156 select GENERIC_ENTRY
6471b825 157 select GENERIC_IOMAP
c7d6c9dd 158 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 159 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 160 select GENERIC_IRQ_MIGRATION if SMP
6471b825 161 select GENERIC_IRQ_PROBE
c201c917 162 select GENERIC_IRQ_RESERVATION_MODE
6471b825
IM
163 select GENERIC_IRQ_SHOW
164 select GENERIC_PENDING_IRQ if SMP
2ae27137 165 select GENERIC_PTDUMP
6471b825 166 select GENERIC_SMP_IDLE_THREAD
6471b825 167 select GENERIC_TIME_VSYSCALL
7ac87074 168 select GENERIC_GETTIMEOFDAY
550a77a7 169 select GENERIC_VDSO_TIME_NS
6ca297d4 170 select GUP_GET_PXX_LOW_HIGH if X86_PAE
17e5888e 171 select HARDIRQS_SW_RESEND
7edaeb68 172 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
fcbfe812 173 select HAS_IOPORT
6471b825
IM
174 select HAVE_ACPI_APEI if ACPI
175 select HAVE_ACPI_APEI_NMI if ACPI
2a19be61 176 select HAVE_ALIGNED_STRUCT_PAGE
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IM
177 select HAVE_ARCH_AUDITSYSCALL
178 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
eed1fcee 179 select HAVE_ARCH_HUGE_VMALLOC if X86_64
6471b825 180 select HAVE_ARCH_JUMP_LABEL
b34006c4 181 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 182 select HAVE_ARCH_KASAN if X86_64
0609ae01 183 select HAVE_ARCH_KASAN_VMALLOC if X86_64
1dc0da6e 184 select HAVE_ARCH_KFENCE
4ca8cc8d 185 select HAVE_ARCH_KMSAN if X86_64
6471b825 186 select HAVE_ARCH_KGDB
9e08f57d
DC
187 select HAVE_ARCH_MMAP_RND_BITS if MMU
188 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 189 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 190 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 191 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 192 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 193 select HAVE_ARCH_STACKLEAK
6471b825
IM
194 select HAVE_ARCH_TRACEHOOK
195 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 196 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 197 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
7677f7fd 198 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD
e37e43a4 199 select HAVE_ARCH_VMAP_STACK if X86_64
fe950f60 200 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
c763ea26 201 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 202 select HAVE_ASM_MODVERSIONS
6471b825
IM
203 select HAVE_CMPXCHG_DOUBLE
204 select HAVE_CMPXCHG_LOCAL
24a9c541
FW
205 select HAVE_CONTEXT_TRACKING_USER if X86_64
206 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER
cf4db259 207 select HAVE_C_RECORDMCOUNT
03f16cd0 208 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL
280981d6 209 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT
4ed308c4 210 select HAVE_BUILDTIME_MCOUNT_SORT
6471b825 211 select HAVE_DEBUG_KMEMLEAK
6471b825 212 select HAVE_DMA_CONTIGUOUS
677aa9f7 213 select HAVE_DYNAMIC_FTRACE
06aeaaea 214 select HAVE_DYNAMIC_FTRACE_WITH_REGS
02a474ca 215 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64
562955fe 216 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
c316eb44 217 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64
503e4510 218 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64
03f5781b 219 select HAVE_EBPF_JIT
58340a07 220 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 221 select HAVE_EISA
5f56a5df 222 select HAVE_EXIT_THREAD
67a929e0 223 select HAVE_FAST_GUP
644e0e8d 224 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 225 select HAVE_FTRACE_MCOUNT_RECORD
d938ba17 226 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
4a30e4c9 227 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE)
6471b825 228 select HAVE_FUNCTION_TRACER
6b90bd4b 229 select HAVE_GCC_PLUGINS
6471b825 230 select HAVE_HW_BREAKPOINT
6471b825 231 select HAVE_IOREMAP_PROT
624db9ea 232 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
6471b825 233 select HAVE_IRQ_TIME_ACCOUNTING
4ab7674f 234 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL
2e9f3bdd 235 select HAVE_KERNEL_BZIP2
6471b825
IM
236 select HAVE_KERNEL_GZIP
237 select HAVE_KERNEL_LZ4
2e9f3bdd 238 select HAVE_KERNEL_LZMA
13510997 239 select HAVE_KERNEL_LZO
6471b825 240 select HAVE_KERNEL_XZ
fb46d057 241 select HAVE_KERNEL_ZSTD
6471b825
IM
242 select HAVE_KPROBES
243 select HAVE_KPROBES_ON_FTRACE
540adea3 244 select HAVE_FUNCTION_ERROR_INJECTION
6471b825 245 select HAVE_KRETPROBES
f3a112c0 246 select HAVE_RETHOOK
6471b825
IM
247 select HAVE_KVM
248 select HAVE_LIVEPATCH if X86_64
0102752e 249 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 250 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 251 select HAVE_MOVE_PMD
be37c98d 252 select HAVE_MOVE_PUD
22102f45 253 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL
42a0bb3f 254 select HAVE_NMI
489e355b 255 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL
03f16cd0 256 select HAVE_OBJTOOL if X86_64
6471b825
IM
257 select HAVE_OPTPROBES
258 select HAVE_PCSPKR_PLATFORM
259 select HAVE_PERF_EVENTS
c01d4323 260 select HAVE_PERF_EVENTS_NMI
92e5aae4 261 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 262 select HAVE_PCI
c5e63197 263 select HAVE_PERF_REGS
c5ebcedb 264 select HAVE_PERF_USER_STACK_DUMP
03f16cd0 265 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
1e9fdf21 266 select MMU_GATHER_MERGE_VMAS
00998085 267 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 268 select HAVE_REGS_AND_STACK_ACCESS_API
03f16cd0 269 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION
3c88ee19 270 select HAVE_FUNCTION_ARG_ACCESS_API
7ecd19cf 271 select HAVE_SETUP_PER_CPU_AREA
cd1a41ce 272 select HAVE_SOFTIRQ_ON_OWN_STACK
d148eac0 273 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
03f16cd0 274 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL
e6d6c071 275 select HAVE_STATIC_CALL
03f16cd0 276 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL
99cf983c 277 select HAVE_PREEMPT_DYNAMIC_CALL
d6761b8f 278 select HAVE_RSEQ
09498135 279 select HAVE_RUST if X86_64
6471b825 280 select HAVE_SYSCALL_TRACEPOINTS
5f3da8c0 281 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL
6471b825 282 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 283 select HAVE_USER_RETURN_NOTIFIER
7ac87074 284 select HAVE_GENERIC_VDSO
0c7ffa32 285 select HOTPLUG_PARALLEL if SMP && X86_64
05736e4a 286 select HOTPLUG_SMT if SMP
0c7ffa32 287 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32
c0185808 288 select IRQ_FORCED_THREADING
c2508ec5 289 select LOCK_MM_AND_FIND_VMA
7ecd19cf
KW
290 select NEED_PER_CPU_EMBED_FIRST_CHUNK
291 select NEED_PER_CPU_PAGE_FIRST_CHUNK
86596f0a 292 select NEED_SG_DMA_LENGTH
2eac9c2d 293 select PCI_DOMAINS if PCI
625210cf 294 select PCI_LOCKLESS_CONFIG if PCI
6471b825 295 select PERF_EVENTS
3195ef59 296 select RTC_LIB
d6faca40 297 select RTC_MC146818_LIB
6471b825 298 select SPARSE_IRQ
6471b825 299 select SYSCTL_EXCEPTION_TRACE
15f4eae7 300 select THREAD_INFO_IN_TASK
4aae683f 301 select TRACE_IRQFLAGS_SUPPORT
4510bffb 302 select TRACE_IRQFLAGS_NMI_SUPPORT
6471b825 303 select USER_STACKTRACE_SUPPORT
3b02a051 304 select HAVE_ARCH_KCSAN if X86_64
0c608dad 305 select PROC_PID_ARCH_STATUS if PROC_FS
50468e43 306 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX
d49a0626
PZ
307 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16
308 select FUNCTION_ALIGNMENT_4B
9e2b4be3 309 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
ceea991a 310 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
7d8330a5 311
ba7e4d13 312config INSTRUCTION_DECODER
3120e25e
JB
313 def_bool y
314 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 315
51b26ada
LT
316config OUTPUT_FORMAT
317 string
318 default "elf32-i386" if X86_32
319 default "elf64-x86-64" if X86_64
320
8d5fffb9 321config LOCKDEP_SUPPORT
3c2362e6 322 def_bool y
8d5fffb9
SR
323
324config STACKTRACE_SUPPORT
3c2362e6 325 def_bool y
8d5fffb9 326
8d5fffb9 327config MMU
3c2362e6 328 def_bool y
8d5fffb9 329
9e08f57d
DC
330config ARCH_MMAP_RND_BITS_MIN
331 default 28 if 64BIT
332 default 8
333
334config ARCH_MMAP_RND_BITS_MAX
335 default 32 if 64BIT
336 default 16
337
338config ARCH_MMAP_RND_COMPAT_BITS_MIN
339 default 8
340
341config ARCH_MMAP_RND_COMPAT_BITS_MAX
342 default 16
343
8d5fffb9
SR
344config SBUS
345 bool
346
347config GENERIC_ISA_DMA
3120e25e
JB
348 def_bool y
349 depends on ISA_DMA_API
8d5fffb9 350
d911c67e
AP
351config GENERIC_CSUM
352 bool
353 default y if KMSAN || KASAN
354
8d5fffb9 355config GENERIC_BUG
3c2362e6 356 def_bool y
8d5fffb9 357 depends on BUG
b93a531e
JB
358 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
359
360config GENERIC_BUG_RELATIVE_POINTERS
361 bool
8d5fffb9 362
8d5fffb9 363config ARCH_MAY_HAVE_PC_FDC
3120e25e
JB
364 def_bool y
365 depends on ISA_DMA_API
8d5fffb9 366
1032c0ba
SR
367config GENERIC_CALIBRATE_DELAY
368 def_bool y
369
9a0b8415 370config ARCH_HAS_CPU_RELAX
371 def_bool y
372
801e4062
JB
373config ARCH_HIBERNATION_POSSIBLE
374 def_bool y
801e4062 375
f4cb5700
JB
376config ARCH_SUSPEND_POSSIBLE
377 def_bool y
f4cb5700 378
8d5fffb9 379config AUDIT_ARCH
e0fd24a3 380 def_bool y if X86_64
8d5fffb9 381
d6f2d75a
AR
382config KASAN_SHADOW_OFFSET
383 hex
384 depends on KASAN
385 default 0xdffffc0000000000
386
69575d38
SW
387config HAVE_INTEL_TXT
388 def_bool y
6ea30386 389 depends on INTEL_IOMMU && ACPI
69575d38 390
6b0c3d44
SR
391config X86_64_SMP
392 def_bool y
393 depends on X86_64 && SMP
394
2b144498
SD
395config ARCH_SUPPORTS_UPROBES
396 def_bool y
397
d20642f0
RH
398config FIX_EARLYCON_MEM
399 def_bool y
400
94d49eb3
KS
401config DYNAMIC_PHYSICAL_MASK
402 bool
403
98233368
KS
404config PGTABLE_LEVELS
405 int
77ef56e4 406 default 5 if X86_5LEVEL
98233368
KS
407 default 4 if X86_64
408 default 3 if X86_PAE
409 default 2
410
2a61f474
MY
411config CC_HAS_SANE_STACKPROTECTOR
412 bool
1b866781
NC
413 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
414 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
2a61f474 415 help
758cd94a
JH
416 We have to make sure stack protector is unconditionally disabled if
417 the compiler produces broken code or if it does not let us control
418 the segment on 32-bit kernels.
2a61f474 419
506f1d07
SR
420menu "Processor type and features"
421
506f1d07
SR
422config SMP
423 bool "Symmetric multi-processing support"
a7f7f624 424 help
506f1d07 425 This enables support for systems with more than one CPU. If you have
4a474157
RG
426 a system with only one CPU, say N. If you have a system with more
427 than one CPU, say Y.
506f1d07 428
4a474157 429 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
430 machines, but will use only one CPU of a multiprocessor machine. If
431 you say Y here, the kernel will run on many, but not all,
4a474157 432 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
433 will run faster if you say N here.
434
435 Note that if you say Y here and choose architecture "586" or
436 "Pentium" under "Processor family", the kernel will not work on 486
437 architectures. Similarly, multiprocessor kernels for the "PPro"
438 architecture may not work on all Pentium based boards.
439
440 People using multiprocessor machines who say Y here should also say
441 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
442 Management" code will be disabled if you say Y here.
443
ff61f079 444 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
4f4cfa6c 445 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
446 <http://www.tldp.org/docs.html#howto>.
447
448 If you don't know what to do here, say N.
449
06cd9a7d
YL
450config X86_X2APIC
451 bool "Support x2apic"
19e3d60d 452 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 453 help
06cd9a7d
YL
454 This enables x2apic support on CPUs that have this feature.
455
456 This allows 32-bit apic IDs (so it can support very large systems),
457 and accesses the local apic via MSRs not via mmio.
458
b8d1d163
DS
459 Some Intel systems circa 2022 and later are locked into x2APIC mode
460 and can not fall back to the legacy APIC modes if SGX or TDX are
e3998434
MJ
461 enabled in the BIOS. They will boot with very reduced functionality
462 without enabling this option.
b8d1d163 463
06cd9a7d
YL
464 If you don't know what to do here, say N.
465
6695c85b 466config X86_MPPARSE
4590d98f 467 bool "Enable MPS table" if ACPI
7a527688 468 default y
5ab74722 469 depends on X86_LOCAL_APIC
a7f7f624 470 help
6695c85b
YL
471 For old smp systems that do not have proper acpi support. Newer systems
472 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 473
ddd70cf9 474config GOLDFISH
b03b016f
KK
475 def_bool y
476 depends on X86_GOLDFISH
ddd70cf9 477
e6d42931
JW
478config X86_CPU_RESCTRL
479 bool "x86 CPU resource control support"
6fe07ce3 480 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 481 select KERNFS
e79f15a4 482 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 483 help
e6d42931 484 Enable x86 CPU resource control support.
6fe07ce3
BM
485
486 Provide support for the allocation and monitoring of system resources
487 usage by the CPU.
488
489 Intel calls this Intel Resource Director Technology
490 (Intel(R) RDT). More information about RDT can be found in the
491 Intel x86 Architecture Software Developer Manual.
492
493 AMD calls this AMD Platform Quality of Service (AMD QoS).
494 More information about AMD QoS can be found in the AMD64 Technology
495 Platform Quality of Service Extensions manual.
78e99b4a
FY
496
497 Say N if unsure.
498
8425091f 499if X86_32
a0d0bb4d
RD
500config X86_BIGSMP
501 bool "Support for big SMP systems with more than 8 CPUs"
502 depends on SMP
a7f7f624 503 help
e133f6ea 504 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 505
c5c606d9
RT
506config X86_EXTENDED_PLATFORM
507 bool "Support for extended (non-PC) x86 platforms"
508 default y
a7f7f624 509 help
06ac8346
IM
510 If you disable this option then the kernel will only support
511 standard PC platforms. (which covers the vast majority of
512 systems out there.)
513
8425091f
RT
514 If you enable this option then you'll be able to select support
515 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 516 Goldfish (Android emulator)
8425091f 517 AMD Elan
8425091f
RT
518 RDC R-321x SoC
519 SGI 320/540 (Visual Workstation)
83125a3a 520 STA2X11-based (e.g. Northville)
3f4110a4 521 Moorestown MID devices
06ac8346
IM
522
523 If you have one of these systems, or if you want to build a
524 generic distribution kernel, say Y here - otherwise say N.
758cd94a 525endif # X86_32
06ac8346 526
8425091f
RT
527if X86_64
528config X86_EXTENDED_PLATFORM
529 bool "Support for extended (non-PC) x86 platforms"
530 default y
a7f7f624 531 help
8425091f
RT
532 If you disable this option then the kernel will only support
533 standard PC platforms. (which covers the vast majority of
534 systems out there.)
535
536 If you enable this option then you'll be able to select support
537 for the following (non-PC) 64 bit x86 platforms:
44b111b5 538 Numascale NumaChip
8425091f
RT
539 ScaleMP vSMP
540 SGI Ultraviolet
541
542 If you have one of these systems, or if you want to build a
543 generic distribution kernel, say Y here - otherwise say N.
758cd94a 544endif # X86_64
c5c606d9
RT
545# This is an alphabetically sorted list of 64 bit extended platforms
546# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
547config X86_NUMACHIP
548 bool "Numascale NumaChip"
549 depends on X86_64
550 depends on X86_EXTENDED_PLATFORM
551 depends on NUMA
552 depends on SMP
553 depends on X86_X2APIC
f9726bfd 554 depends on PCI_MMCONFIG
a7f7f624 555 help
44b111b5
SP
556 Adds support for Numascale NumaChip large-SMP systems. Needed to
557 enable more than ~168 cores.
558 If you don't have one of these, you should say N here.
506f1d07 559
c5c606d9
RT
560config X86_VSMP
561 bool "ScaleMP vSMP"
6276a074 562 select HYPERVISOR_GUEST
c5c606d9
RT
563 select PARAVIRT
564 depends on X86_64 && PCI
565 depends on X86_EXTENDED_PLATFORM
ead91d4b 566 depends on SMP
a7f7f624 567 help
c5c606d9
RT
568 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
569 supposed to run on these EM64T-based machines. Only choose this option
570 if you have one of these machines.
5e3a77e9 571
03b48632
NP
572config X86_UV
573 bool "SGI Ultraviolet"
574 depends on X86_64
c5c606d9 575 depends on X86_EXTENDED_PLATFORM
54c28d29 576 depends on NUMA
1ecb4ae5 577 depends on EFI
c2209ea5 578 depends on KEXEC_CORE
9d6c26e7 579 depends on X86_X2APIC
1222e564 580 depends on PCI
a7f7f624 581 help
03b48632
NP
582 This option is needed in order to support SGI Ultraviolet systems.
583 If you don't have one of these, you should say N here.
584
c5c606d9
RT
585# Following is an alphabetically sorted list of 32 bit extended platforms
586# Please maintain the alphabetic order if and when there are additions
506f1d07 587
ddd70cf9 588config X86_GOLDFISH
b03b016f
KK
589 bool "Goldfish (Virtual Platform)"
590 depends on X86_EXTENDED_PLATFORM
a7f7f624 591 help
758cd94a
JH
592 Enable support for the Goldfish virtual platform used primarily
593 for Android development. Unless you are building for the Android
594 Goldfish emulator say N here.
ddd70cf9 595
c751e17b
TG
596config X86_INTEL_CE
597 bool "CE4100 TV platform"
598 depends on PCI
599 depends on PCI_GODIRECT
6084a6e2 600 depends on X86_IO_APIC
c751e17b
TG
601 depends on X86_32
602 depends on X86_EXTENDED_PLATFORM
37bc9f50 603 select X86_REBOOTFIXUPS
da6b737b
SAS
604 select OF
605 select OF_EARLY_FLATTREE
a7f7f624 606 help
c751e17b
TG
607 Select for the Intel CE media processor (CE4100) SOC.
608 This option compiles in support for the CE4100 SOC for settop
609 boxes and media devices.
610
4cb9b00f 611config X86_INTEL_MID
43605ef1 612 bool "Intel MID platform support"
43605ef1 613 depends on X86_EXTENDED_PLATFORM
edc6bc78 614 depends on X86_PLATFORM_DEVICES
1ea7c673 615 depends on PCI
3fda5bb4 616 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 617 depends on X86_IO_APIC
4cb9b00f 618 select I2C
7c9c3a1e 619 select DW_APB_TIMER
54b34aa0 620 select INTEL_SCU_PCI
a7f7f624 621 help
4cb9b00f
DC
622 Select to build a kernel capable of supporting Intel MID (Mobile
623 Internet Device) platform systems which do not have the PCI legacy
624 interfaces. If you are building for a PC class system say N here.
1ea7c673 625
4cb9b00f
DC
626 Intel MID platforms are based on an Intel processor and chipset which
627 consume less power than most of the x86 derivatives.
43605ef1 628
8bbc2a13
BD
629config X86_INTEL_QUARK
630 bool "Intel Quark platform support"
631 depends on X86_32
632 depends on X86_EXTENDED_PLATFORM
633 depends on X86_PLATFORM_DEVICES
634 depends on X86_TSC
635 depends on PCI
636 depends on PCI_GOANY
637 depends on X86_IO_APIC
638 select IOSF_MBI
639 select INTEL_IMR
9ab6eb51 640 select COMMON_CLK
a7f7f624 641 help
8bbc2a13
BD
642 Select to include support for Quark X1000 SoC.
643 Say Y here if you have a Quark based system such as the Arduino
644 compatible Intel Galileo.
645
3d48aab1
MW
646config X86_INTEL_LPSS
647 bool "Intel Low Power Subsystem Support"
5962dd22 648 depends on X86 && ACPI && PCI
3d48aab1 649 select COMMON_CLK
0f531431 650 select PINCTRL
eebb3e8d 651 select IOSF_MBI
a7f7f624 652 help
3d48aab1
MW
653 Select to build support for Intel Low Power Subsystem such as
654 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
655 things like clock tree (common clock framework) and pincontrol
656 which are needed by the LPSS peripheral drivers.
3d48aab1 657
92082a88
KX
658config X86_AMD_PLATFORM_DEVICE
659 bool "AMD ACPI2Platform devices support"
660 depends on ACPI
661 select COMMON_CLK
662 select PINCTRL
a7f7f624 663 help
92082a88
KX
664 Select to interpret AMD specific ACPI device to platform device
665 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
666 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
667 implemented under PINCTRL subsystem.
668
ced3ce76
DB
669config IOSF_MBI
670 tristate "Intel SoC IOSF Sideband support for SoC platforms"
671 depends on PCI
a7f7f624 672 help
ced3ce76
DB
673 This option enables sideband register access support for Intel SoC
674 platforms. On these platforms the IOSF sideband is used in lieu of
675 MSR's for some register accesses, mostly but not limited to thermal
676 and power. Drivers may query the availability of this device to
677 determine if they need the sideband in order to work on these
678 platforms. The sideband is available on the following SoC products.
679 This list is not meant to be exclusive.
680 - BayTrail
681 - Braswell
682 - Quark
683
684 You should say Y if you are running a kernel on one of these SoC's.
685
ed2226bd
DB
686config IOSF_MBI_DEBUG
687 bool "Enable IOSF sideband access through debugfs"
688 depends on IOSF_MBI && DEBUG_FS
a7f7f624 689 help
ed2226bd
DB
690 Select this option to expose the IOSF sideband access registers (MCR,
691 MDR, MCRX) through debugfs to write and read register information from
692 different units on the SoC. This is most useful for obtaining device
693 state information for debug and analysis. As this is a general access
694 mechanism, users of this option would have specific knowledge of the
695 device they want to access.
696
697 If you don't require the option or are in doubt, say N.
698
c5c606d9
RT
699config X86_RDC321X
700 bool "RDC R-321x SoC"
506f1d07 701 depends on X86_32
c5c606d9
RT
702 depends on X86_EXTENDED_PLATFORM
703 select M486
704 select X86_REBOOTFIXUPS
a7f7f624 705 help
c5c606d9
RT
706 This option is needed for RDC R-321x system-on-chip, also known
707 as R-8610-(G).
708 If you don't have one of these chips, you should say N here.
709
e0c7ae37 710config X86_32_NON_STANDARD
9c398017
IM
711 bool "Support non-standard 32-bit SMP architectures"
712 depends on X86_32 && SMP
c5c606d9 713 depends on X86_EXTENDED_PLATFORM
a7f7f624 714 help
b5660ba7
PA
715 This option compiles in the bigsmp and STA2X11 default
716 subarchitectures. It is intended for a generic binary
717 kernel. If you select them all, kernel will probe it one by
718 one and will fallback to default.
d49c4288 719
c5c606d9 720# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 721
d949f36f 722config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 723 def_bool y
d949f36f
LT
724 # MCE code calls memory_failure():
725 depends on X86_MCE
726 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
727 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
728 depends on X86_64 || !SPARSEMEM
729 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 730
83125a3a
AR
731config STA2X11
732 bool "STA2X11 Companion Chip Support"
733 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
734 select SWIOTLB
735 select MFD_STA2X11
0145071b 736 select GPIOLIB
a7f7f624 737 help
83125a3a
AR
738 This adds support for boards based on the STA2X11 IO-Hub,
739 a.k.a. "ConneXt". The chip is used in place of the standard
740 PC chipset, so all "standard" peripherals are missing. If this
741 option is selected the kernel will still be able to boot on
742 standard PC machines.
743
82148d1d
S
744config X86_32_IRIS
745 tristate "Eurobraille/Iris poweroff module"
746 depends on X86_32
a7f7f624 747 help
82148d1d
S
748 The Iris machines from EuroBraille do not have APM or ACPI support
749 to shut themselves down properly. A special I/O sequence is
750 needed to do so, which is what this module does at
751 kernel shutdown.
752
753 This is only for Iris machines from EuroBraille.
754
755 If unused, say N.
756
ae1e9130 757config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
758 def_bool y
759 prompt "Single-depth WCHAN output"
a87d0914 760 depends on X86
a7f7f624 761 help
506f1d07
SR
762 Calculate simpler /proc/<PID>/wchan values. If this option
763 is disabled then wchan values will recurse back to the
764 caller function. This provides more accurate wchan values,
765 at the expense of slightly more scheduling overhead.
766
767 If in doubt, say "Y".
768
6276a074
BP
769menuconfig HYPERVISOR_GUEST
770 bool "Linux guest support"
a7f7f624 771 help
6276a074
BP
772 Say Y here to enable options for running Linux under various hyper-
773 visors. This option enables basic hypervisor detection and platform
774 setup.
506f1d07 775
6276a074
BP
776 If you say N, all options in this submenu will be skipped and
777 disabled, and Linux guest support won't be built in.
506f1d07 778
6276a074 779if HYPERVISOR_GUEST
506f1d07 780
e61bd94a
EPH
781config PARAVIRT
782 bool "Enable paravirtualization code"
a0e2bf7c 783 depends on HAVE_STATIC_CALL
a7f7f624 784 help
e61bd94a
EPH
785 This changes the kernel so it can modify itself when it is run
786 under a hypervisor, potentially improving performance significantly
787 over full virtualization. However, when run without a hypervisor
788 the kernel is theoretically slower and slightly larger.
789
c00a280a
JG
790config PARAVIRT_XXL
791 bool
792
6276a074
BP
793config PARAVIRT_DEBUG
794 bool "paravirt-ops debugging"
795 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 796 help
6276a074
BP
797 Enable to debug paravirt_ops internals. Specifically, BUG if
798 a paravirt_op is missing when it is called.
799
b4ecc126
JF
800config PARAVIRT_SPINLOCKS
801 bool "Paravirtualization layer for spinlocks"
6ea30386 802 depends on PARAVIRT && SMP
a7f7f624 803 help
b4ecc126
JF
804 Paravirtualized spinlocks allow a pvops backend to replace the
805 spinlock implementation with something virtualization-friendly
806 (for example, block the virtual CPU rather than spinning).
807
4c4e4f61
R
808 It has a minimal impact on native kernels and gives a nice performance
809 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 810
4c4e4f61 811 If you are unsure how to answer this question, answer Y.
b4ecc126 812
ecca2502
ZY
813config X86_HV_CALLBACK_VECTOR
814 def_bool n
815
6276a074 816source "arch/x86/xen/Kconfig"
7af192c9 817
6276a074
BP
818config KVM_GUEST
819 bool "KVM Guest support (including kvmclock)"
820 depends on PARAVIRT
821 select PARAVIRT_CLOCK
a1c4423b 822 select ARCH_CPUIDLE_HALTPOLL
b1d40575 823 select X86_HV_CALLBACK_VECTOR
6276a074 824 default y
a7f7f624 825 help
6276a074
BP
826 This option enables various optimizations for running under the KVM
827 hypervisor. It includes a paravirtualized clock, so that instead
828 of relying on a PIT (or probably other) emulation by the
829 underlying device model, the host provides the guest with
830 timing infrastructure such as time of day, and system time
506f1d07 831
a1c4423b 832config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
833 def_bool n
834 prompt "Disable host haltpoll when loading haltpoll driver"
835 help
a1c4423b
MT
836 If virtualized under KVM, disable host haltpoll.
837
7733607f
MW
838config PVH
839 bool "Support for running PVH guests"
a7f7f624 840 help
7733607f
MW
841 This option enables the PVH entry point for guest virtual machines
842 as specified in the x86/HVM direct boot ABI.
843
6276a074
BP
844config PARAVIRT_TIME_ACCOUNTING
845 bool "Paravirtual steal time accounting"
846 depends on PARAVIRT
a7f7f624 847 help
6276a074
BP
848 Select this option to enable fine granularity task steal time
849 accounting. Time spent executing other tasks in parallel with
850 the current vCPU is discounted from the vCPU power. To account for
851 that, there can be a small performance impact.
852
853 If in doubt, say N here.
854
855config PARAVIRT_CLOCK
856 bool
97349135 857
4a362601
JK
858config JAILHOUSE_GUEST
859 bool "Jailhouse non-root cell support"
abde587b 860 depends on X86_64 && PCI
87e65d05 861 select X86_PM_TIMER
a7f7f624 862 help
4a362601
JK
863 This option allows to run Linux as guest in a Jailhouse non-root
864 cell. You can leave this option disabled if you only want to start
865 Jailhouse and run Linux afterwards in the root cell.
866
ec7972c9
ZY
867config ACRN_GUEST
868 bool "ACRN Guest support"
869 depends on X86_64
498ad393 870 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
871 help
872 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
873 a flexible, lightweight reference open-source hypervisor, built with
874 real-time and safety-criticality in mind. It is built for embedded
875 IOT with small footprint and real-time features. More details can be
876 found in https://projectacrn.org/.
877
59bd54a8
KS
878config INTEL_TDX_GUEST
879 bool "Intel TDX (Trust Domain Extensions) - Guest Support"
880 depends on X86_64 && CPU_SUP_INTEL
881 depends on X86_X2APIC
75d090fd 882 depends on EFI_STUB
41394e33 883 select ARCH_HAS_CC_PLATFORM
968b4931 884 select X86_MEM_ENCRYPT
77a512e3 885 select X86_MCE
75d090fd 886 select UNACCEPTED_MEMORY
59bd54a8
KS
887 help
888 Support running as a guest under Intel TDX. Without this support,
889 the guest kernel can not boot or run under TDX.
890 TDX includes memory encryption and integrity capabilities
891 which protect the confidentiality and integrity of guest
892 memory contents and CPU state. TDX guests are protected from
893 some attacks from the VMM.
894
758cd94a 895endif # HYPERVISOR_GUEST
97349135 896
506f1d07
SR
897source "arch/x86/Kconfig.cpu"
898
899config HPET_TIMER
3c2362e6 900 def_bool X86_64
506f1d07 901 prompt "HPET Timer Support" if X86_32
a7f7f624 902 help
8f9ca475
IM
903 Use the IA-PC HPET (High Precision Event Timer) to manage
904 time in preference to the PIT and RTC, if a HPET is
905 present.
906 HPET is the next generation timer replacing legacy 8254s.
907 The HPET provides a stable time base on SMP
908 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
909 as it is off-chip. The interface used is documented
910 in the HPET spec, revision 1.
506f1d07 911
8f9ca475
IM
912 You can safely choose Y here. However, HPET will only be
913 activated if the platform and the BIOS support this feature.
914 Otherwise the 8254 will be used for timing services.
506f1d07 915
8f9ca475 916 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
917
918config HPET_EMULATE_RTC
3c2362e6 919 def_bool y
3228e1dc 920 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 921
6a108a14 922# Mark as expert because too many people got it wrong.
506f1d07 923# The code disables itself when not needed.
7ae9392c
TP
924config DMI
925 default y
cf074402 926 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 927 bool "Enable DMI scanning" if EXPERT
a7f7f624 928 help
7ae9392c
TP
929 Enabled scanning of DMI to identify machine quirks. Say Y
930 here unless you have verified that your setup is not
931 affected by entries in the DMI blacklist. Required by PNP
932 BIOS code.
933
506f1d07 934config GART_IOMMU
38901f1c 935 bool "Old AMD GART IOMMU support"
2f9237d4 936 select DMA_OPS
a4ce5a48 937 select IOMMU_HELPER
506f1d07 938 select SWIOTLB
23ac4ae8 939 depends on X86_64 && PCI && AMD_NB
a7f7f624 940 help
ced3c42c
IM
941 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
942 GART based hardware IOMMUs.
943
944 The GART supports full DMA access for devices with 32-bit access
945 limitations, on systems with more than 3 GB. This is usually needed
946 for USB, sound, many IDE/SATA chipsets and some other devices.
947
948 Newer systems typically have a modern AMD IOMMU, supported via
949 the CONFIG_AMD_IOMMU=y config option.
950
951 In normal configurations this driver is only active when needed:
952 there's more than 3 GB of memory and the system contains a
953 32-bit limited device.
954
955 If unsure, say Y.
506f1d07 956
8b766b0f
MS
957config BOOT_VESA_SUPPORT
958 bool
959 help
960 If true, at least one selected framebuffer driver can take advantage
961 of VESA video modes set at an early boot stage via the vga= parameter.
506f1d07 962
1184dc2f 963config MAXSMP
ddb0c5a6 964 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 965 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 966 select CPUMASK_OFFSTACK
a7f7f624 967 help
ddb0c5a6 968 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 969 If unsure, say N.
506f1d07 970
aec6487e
IM
971#
972# The maximum number of CPUs supported:
973#
974# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
975# and which can be configured interactively in the
976# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
977#
978# The ranges are different on 32-bit and 64-bit kernels, depending on
979# hardware capabilities and scalability features of the kernel.
980#
981# ( If MAXSMP is enabled we just use the highest possible value and disable
982# interactive configuration. )
983#
984
985config NR_CPUS_RANGE_BEGIN
a0d0bb4d 986 int
aec6487e
IM
987 default NR_CPUS_RANGE_END if MAXSMP
988 default 1 if !SMP
989 default 2
a0d0bb4d 990
aec6487e 991config NR_CPUS_RANGE_END
a0d0bb4d 992 int
aec6487e
IM
993 depends on X86_32
994 default 64 if SMP && X86_BIGSMP
995 default 8 if SMP && !X86_BIGSMP
996 default 1 if !SMP
a0d0bb4d 997
aec6487e 998config NR_CPUS_RANGE_END
a0d0bb4d 999 int
aec6487e 1000 depends on X86_64
1edae1ae
SW
1001 default 8192 if SMP && CPUMASK_OFFSTACK
1002 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 1003 default 1 if !SMP
a0d0bb4d 1004
aec6487e 1005config NR_CPUS_DEFAULT
a0d0bb4d
RD
1006 int
1007 depends on X86_32
aec6487e
IM
1008 default 32 if X86_BIGSMP
1009 default 8 if SMP
1010 default 1 if !SMP
a0d0bb4d 1011
aec6487e 1012config NR_CPUS_DEFAULT
a0d0bb4d
RD
1013 int
1014 depends on X86_64
aec6487e
IM
1015 default 8192 if MAXSMP
1016 default 64 if SMP
1017 default 1 if !SMP
a0d0bb4d 1018
506f1d07 1019config NR_CPUS
36f5101a 1020 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
1021 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1022 default NR_CPUS_DEFAULT
a7f7f624 1023 help
506f1d07 1024 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1025 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1026 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1027 minimum value which makes sense is 2.
1028
aec6487e
IM
1029 This is purely to save memory: each supported CPU adds about 8KB
1030 to the kernel image.
506f1d07 1031
66558b73
TC
1032config SCHED_CLUSTER
1033 bool "Cluster scheduler support"
1034 depends on SMP
1035 default y
1036 help
1037 Cluster scheduler support improves the CPU scheduler's decision
1038 making when dealing with machines that have clusters of CPUs.
1039 Cluster usually means a couple of CPUs which are placed closely
1040 by sharing mid-level caches, last-level cache tags or internal
1041 busses.
1042
506f1d07 1043config SCHED_SMT
dbe73364 1044 def_bool y if SMP
506f1d07
SR
1045
1046config SCHED_MC
3c2362e6
HH
1047 def_bool y
1048 prompt "Multi-core scheduler support"
c8e56d20 1049 depends on SMP
a7f7f624 1050 help
506f1d07
SR
1051 Multi-core scheduler support improves the CPU scheduler's decision
1052 making when dealing with multi-core CPU chips at a cost of slightly
1053 increased overhead in some places. If unsure say N here.
1054
de966cf4
TC
1055config SCHED_MC_PRIO
1056 bool "CPU core priorities scheduler support"
0a21fc12
IM
1057 depends on SCHED_MC && CPU_SUP_INTEL
1058 select X86_INTEL_PSTATE
1059 select CPU_FREQ
de966cf4 1060 default y
a7f7f624 1061 help
0a21fc12
IM
1062 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1063 core ordering determined at manufacturing time, which allows
1064 certain cores to reach higher turbo frequencies (when running
1065 single threaded workloads) than others.
de966cf4 1066
0a21fc12
IM
1067 Enabling this kernel feature teaches the scheduler about
1068 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1069 scheduler's CPU selection logic accordingly, so that higher
1070 overall system performance can be achieved.
de966cf4 1071
0a21fc12 1072 This feature will have no effect on CPUs without this feature.
de966cf4 1073
0a21fc12 1074 If unsure say Y here.
5e76b2ab 1075
30b8b006 1076config UP_LATE_INIT
b03b016f
KK
1077 def_bool y
1078 depends on !SMP && X86_LOCAL_APIC
30b8b006 1079
506f1d07 1080config X86_UP_APIC
50849eef
JB
1081 bool "Local APIC support on uniprocessors" if !PCI_MSI
1082 default PCI_MSI
38a1dfda 1083 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1084 help
506f1d07
SR
1085 A local APIC (Advanced Programmable Interrupt Controller) is an
1086 integrated interrupt controller in the CPU. If you have a single-CPU
1087 system which has a processor with a local APIC, you can say Y here to
1088 enable and use it. If you say Y here even though your machine doesn't
1089 have a local APIC, then the kernel will still run with no slowdown at
1090 all. The local APIC supports CPU-generated self-interrupts (timer,
1091 performance counters), and the NMI watchdog which detects hard
1092 lockups.
1093
1094config X86_UP_IOAPIC
1095 bool "IO-APIC support on uniprocessors"
1096 depends on X86_UP_APIC
a7f7f624 1097 help
506f1d07
SR
1098 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1099 SMP-capable replacement for PC-style interrupt controllers. Most
1100 SMP systems and many recent uniprocessor systems have one.
1101
1102 If you have a single-CPU system with an IO-APIC, you can say Y here
1103 to use it. If you say Y here even though your machine doesn't have
1104 an IO-APIC, then the kernel will still run with no slowdown at all.
1105
1106config X86_LOCAL_APIC
3c2362e6 1107 def_bool y
0dbc6078 1108 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1109 select IRQ_DOMAIN_HIERARCHY
506f1d07
SR
1110
1111config X86_IO_APIC
b1da1e71
JB
1112 def_bool y
1113 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1114
41b9eb26
SA
1115config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1116 bool "Reroute for broken boot IRQs"
41b9eb26 1117 depends on X86_IO_APIC
a7f7f624 1118 help
41b9eb26
SA
1119 This option enables a workaround that fixes a source of
1120 spurious interrupts. This is recommended when threaded
1121 interrupt handling is used on systems where the generation of
1122 superfluous "boot interrupts" cannot be disabled.
1123
1124 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1125 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1126 kernel does during interrupt handling). On chipsets where this
1127 boot IRQ generation cannot be disabled, this workaround keeps
1128 the original IRQ line masked so that only the equivalent "boot
1129 IRQ" is delivered to the CPUs. The workaround also tells the
1130 kernel to set up the IRQ handler on the boot IRQ line. In this
1131 way only one interrupt is delivered to the kernel. Otherwise
1132 the spurious second interrupt may cause the kernel to bring
1133 down (vital) interrupt lines.
1134
1135 Only affects "broken" chipsets. Interrupt sharing may be
1136 increased on these systems.
1137
506f1d07 1138config X86_MCE
bab9bc65 1139 bool "Machine Check / overheating reporting"
648ed940 1140 select GENERIC_ALLOCATOR
e57dbaf7 1141 default y
a7f7f624 1142 help
bab9bc65
AK
1143 Machine Check support allows the processor to notify the
1144 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1145 The action the kernel takes depends on the severity of the problem,
bab9bc65 1146 ranging from warning messages to halting the machine.
4efc0670 1147
5de97c9f
TL
1148config X86_MCELOG_LEGACY
1149 bool "Support for deprecated /dev/mcelog character device"
1150 depends on X86_MCE
a7f7f624 1151 help
5de97c9f
TL
1152 Enable support for /dev/mcelog which is needed by the old mcelog
1153 userspace logging daemon. Consider switching to the new generation
1154 rasdaemon solution.
1155
506f1d07 1156config X86_MCE_INTEL
3c2362e6
HH
1157 def_bool y
1158 prompt "Intel MCE features"
c1ebf835 1159 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1160 help
758cd94a
JH
1161 Additional support for intel specific MCE features such as
1162 the thermal monitor.
506f1d07
SR
1163
1164config X86_MCE_AMD
3c2362e6
HH
1165 def_bool y
1166 prompt "AMD MCE features"
f5382de9 1167 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
a7f7f624 1168 help
758cd94a
JH
1169 Additional support for AMD specific MCE features such as
1170 the DRAM Error Threshold.
506f1d07 1171
4efc0670 1172config X86_ANCIENT_MCE
6fc108a0 1173 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1174 depends on X86_32 && X86_MCE
a7f7f624 1175 help
cd13adcc 1176 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1177 systems. These typically need to be enabled explicitly on the command
cd13adcc 1178 line.
4efc0670 1179
b2762686
AK
1180config X86_MCE_THRESHOLD
1181 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1182 def_bool y
b2762686 1183
ea149b36 1184config X86_MCE_INJECT
bc8e80d5 1185 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1186 tristate "Machine check injector support"
a7f7f624 1187 help
ea149b36
AK
1188 Provide support for injecting machine checks for testing purposes.
1189 If you don't know what a machine check is and you don't do kernel
1190 QA it is safe to say n.
1191
07dc900e 1192source "arch/x86/events/Kconfig"
e633c65a 1193
5aef51c3 1194config X86_LEGACY_VM86
1e642812 1195 bool "Legacy VM86 support"
506f1d07 1196 depends on X86_32
a7f7f624 1197 help
5aef51c3
AL
1198 This option allows user programs to put the CPU into V8086
1199 mode, which is an 80286-era approximation of 16-bit real mode.
1200
1201 Some very old versions of X and/or vbetool require this option
1202 for user mode setting. Similarly, DOSEMU will use it if
1203 available to accelerate real mode DOS programs. However, any
1204 recent version of DOSEMU, X, or vbetool should be fully
1205 functional even without kernel VM86 support, as they will all
1e642812
IM
1206 fall back to software emulation. Nevertheless, if you are using
1207 a 16-bit DOS program where 16-bit performance matters, vm86
1208 mode might be faster than emulation and you might want to
1209 enable this option.
5aef51c3 1210
1e642812
IM
1211 Note that any app that works on a 64-bit kernel is unlikely to
1212 need this option, as 64-bit kernels don't, and can't, support
1213 V8086 mode. This option is also unrelated to 16-bit protected
1214 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1215
1e642812
IM
1216 Enabling this option increases the complexity of the kernel
1217 and slows down exception handling a tiny bit.
5aef51c3 1218
1e642812 1219 If unsure, say N here.
5aef51c3
AL
1220
1221config VM86
b03b016f
KK
1222 bool
1223 default X86_LEGACY_VM86
34273f41
PA
1224
1225config X86_16BIT
1226 bool "Enable support for 16-bit segments" if EXPERT
1227 default y
a5b9e5a2 1228 depends on MODIFY_LDT_SYSCALL
a7f7f624 1229 help
34273f41
PA
1230 This option is required by programs like Wine to run 16-bit
1231 protected mode legacy code on x86 processors. Disabling
1232 this option saves about 300 bytes on i386, or around 6K text
1233 plus 16K runtime memory on x86-64,
1234
1235config X86_ESPFIX32
1236 def_bool y
1237 depends on X86_16BIT && X86_32
506f1d07 1238
197725de
PA
1239config X86_ESPFIX64
1240 def_bool y
34273f41 1241 depends on X86_16BIT && X86_64
506f1d07 1242
1ad83c85 1243config X86_VSYSCALL_EMULATION
b03b016f
KK
1244 bool "Enable vsyscall emulation" if EXPERT
1245 default y
1246 depends on X86_64
a7f7f624 1247 help
758cd94a
JH
1248 This enables emulation of the legacy vsyscall page. Disabling
1249 it is roughly equivalent to booting with vsyscall=none, except
1250 that it will also disable the helpful warning if a program
1251 tries to use a vsyscall. With this option set to N, offending
1252 programs will just segfault, citing addresses of the form
1253 0xffffffffff600?00.
1ad83c85 1254
758cd94a
JH
1255 This option is required by many programs built before 2013, and
1256 care should be used even with newer programs if set to N.
1ad83c85 1257
758cd94a
JH
1258 Disabling this option saves about 7K of kernel size and
1259 possibly 4K of additional runtime pagetable memory.
1ad83c85 1260
111e7b15
TG
1261config X86_IOPL_IOPERM
1262 bool "IOPERM and IOPL Emulation"
a24ca997 1263 default y
a7f7f624 1264 help
111e7b15
TG
1265 This enables the ioperm() and iopl() syscalls which are necessary
1266 for legacy applications.
1267
c8137ace
TG
1268 Legacy IOPL support is an overbroad mechanism which allows user
1269 space aside of accessing all 65536 I/O ports also to disable
1270 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1271 capabilities and permission from potentially active security
1272 modules.
1273
1274 The emulation restricts the functionality of the syscall to
1275 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1276 ability to disable interrupts from user space which would be
1277 granted if the hardware IOPL mechanism would be used.
c8137ace 1278
506f1d07
SR
1279config TOSHIBA
1280 tristate "Toshiba Laptop support"
1281 depends on X86_32
a7f7f624 1282 help
506f1d07
SR
1283 This adds a driver to safely access the System Management Mode of
1284 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1285 not work on models with a Phoenix BIOS. The System Management Mode
1286 is used to set the BIOS and power saving options on Toshiba portables.
1287
1288 For information on utilities to make use of this driver see the
1289 Toshiba Linux utilities web site at:
1290 <http://www.buzzard.org.uk/toshiba/>.
1291
1292 Say Y if you intend to run this kernel on a Toshiba portable.
1293 Say N otherwise.
1294
506f1d07 1295config X86_REBOOTFIXUPS
9ba16087
JB
1296 bool "Enable X86 board specific fixups for reboot"
1297 depends on X86_32
a7f7f624 1298 help
506f1d07
SR
1299 This enables chipset and/or board specific fixups to be done
1300 in order to get reboot to work correctly. This is only needed on
1301 some combinations of hardware and BIOS. The symptom, for which
1302 this config is intended, is when reboot ends with a stalled/hung
1303 system.
1304
1305 Currently, the only fixup is for the Geode machines using
5e3a77e9 1306 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1307
1308 Say Y if you want to enable the fixup. Currently, it's safe to
1309 enable this option even if you don't need it.
1310 Say N otherwise.
1311
1312config MICROCODE
e6bcfdd7 1313 def_bool y
80030e3d 1314 depends on CPU_SUP_AMD || CPU_SUP_INTEL
80cc9f10 1315
fdbd4381
TG
1316config MICROCODE_INITRD32
1317 def_bool y
1318 depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1319
a77a94f8
BP
1320config MICROCODE_LATE_LOADING
1321 bool "Late microcode loading (DANGEROUS)"
c02f48e0 1322 default n
634ac23a 1323 depends on MICROCODE && SMP
a7f7f624 1324 help
a77a94f8
BP
1325 Loading microcode late, when the system is up and executing instructions
1326 is a tricky business and should be avoided if possible. Just the sequence
1327 of synchronizing all cores and SMT threads is one fragile dance which does
1328 not guarantee that cores might not softlock after the loading. Therefore,
9407bda8
TG
1329 use this at your own risk. Late loading taints the kernel unless the
1330 microcode header indicates that it is safe for late loading via the
1331 minimal revision check. This minimal revision check can be enforced on
1332 the kernel command line with "microcode.minrev=Y".
1333
1334config MICROCODE_LATE_FORCE_MINREV
1335 bool "Enforce late microcode loading minimal revision check"
1336 default n
1337 depends on MICROCODE_LATE_LOADING
1338 help
1339 To prevent that users load microcode late which modifies already
1340 in use features, newer microcode patches have a minimum revision field
1341 in the microcode header, which tells the kernel which minimum
1342 revision must be active in the CPU to safely load that new microcode
1343 late into the running system. If disabled the check will not
1344 be enforced but the kernel will be tainted when the minimal
1345 revision check fails.
1346
1347 This minimal revision check can also be controlled via the
1348 "microcode.minrev" parameter on the kernel command line.
1349
1350 If unsure say Y.
506f1d07
SR
1351
1352config X86_MSR
1353 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1354 help
506f1d07
SR
1355 This device gives privileged processes access to the x86
1356 Model-Specific Registers (MSRs). It is a character device with
1357 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1358 MSR accesses are directed to a specific CPU on multi-processor
1359 systems.
1360
1361config X86_CPUID
1362 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1363 help
506f1d07
SR
1364 This device gives processes access to the x86 CPUID instruction to
1365 be executed on a specific processor. It is a character device
1366 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1367 /dev/cpu/31/cpuid.
1368
1369choice
1370 prompt "High Memory Support"
6fc108a0 1371 default HIGHMEM4G
506f1d07
SR
1372 depends on X86_32
1373
1374config NOHIGHMEM
1375 bool "off"
a7f7f624 1376 help
506f1d07
SR
1377 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1378 However, the address space of 32-bit x86 processors is only 4
1379 Gigabytes large. That means that, if you have a large amount of
1380 physical memory, not all of it can be "permanently mapped" by the
1381 kernel. The physical memory that's not permanently mapped is called
1382 "high memory".
1383
1384 If you are compiling a kernel which will never run on a machine with
1385 more than 1 Gigabyte total physical RAM, answer "off" here (default
1386 choice and suitable for most users). This will result in a "3GB/1GB"
1387 split: 3GB are mapped so that each process sees a 3GB virtual memory
1388 space and the remaining part of the 4GB virtual memory space is used
1389 by the kernel to permanently map as much physical memory as
1390 possible.
1391
1392 If the machine has between 1 and 4 Gigabytes physical RAM, then
1393 answer "4GB" here.
1394
1395 If more than 4 Gigabytes is used then answer "64GB" here. This
1396 selection turns Intel PAE (Physical Address Extension) mode on.
1397 PAE implements 3-level paging on IA32 processors. PAE is fully
1398 supported by Linux, PAE mode is implemented on all recent Intel
1399 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1400 then the kernel will not boot on CPUs that don't support PAE!
1401
1402 The actual amount of total physical memory will either be
1403 auto detected or can be forced by using a kernel command line option
1404 such as "mem=256M". (Try "man bootparam" or see the documentation of
1405 your boot loader (lilo or loadlin) about how to pass options to the
1406 kernel at boot time.)
1407
1408 If unsure, say "off".
1409
1410config HIGHMEM4G
1411 bool "4GB"
a7f7f624 1412 help
506f1d07
SR
1413 Select this if you have a 32-bit processor and between 1 and 4
1414 gigabytes of physical RAM.
1415
1416config HIGHMEM64G
1417 bool "64GB"
88a2b4ed 1418 depends on X86_HAVE_PAE
506f1d07 1419 select X86_PAE
a7f7f624 1420 help
506f1d07
SR
1421 Select this if you have a 32-bit processor and more than 4
1422 gigabytes of physical RAM.
1423
1424endchoice
1425
1426choice
6a108a14 1427 prompt "Memory split" if EXPERT
506f1d07
SR
1428 default VMSPLIT_3G
1429 depends on X86_32
a7f7f624 1430 help
506f1d07
SR
1431 Select the desired split between kernel and user memory.
1432
1433 If the address range available to the kernel is less than the
1434 physical memory installed, the remaining memory will be available
1435 as "high memory". Accessing high memory is a little more costly
1436 than low memory, as it needs to be mapped into the kernel first.
1437 Note that increasing the kernel address space limits the range
1438 available to user programs, making the address space there
1439 tighter. Selecting anything other than the default 3G/1G split
1440 will also likely make your kernel incompatible with binary-only
1441 kernel modules.
1442
1443 If you are not absolutely sure what you are doing, leave this
1444 option alone!
1445
1446 config VMSPLIT_3G
1447 bool "3G/1G user/kernel split"
1448 config VMSPLIT_3G_OPT
1449 depends on !X86_PAE
1450 bool "3G/1G user/kernel split (for full 1G low memory)"
1451 config VMSPLIT_2G
1452 bool "2G/2G user/kernel split"
1453 config VMSPLIT_2G_OPT
1454 depends on !X86_PAE
1455 bool "2G/2G user/kernel split (for full 2G low memory)"
1456 config VMSPLIT_1G
1457 bool "1G/3G user/kernel split"
1458endchoice
1459
1460config PAGE_OFFSET
1461 hex
1462 default 0xB0000000 if VMSPLIT_3G_OPT
1463 default 0x80000000 if VMSPLIT_2G
1464 default 0x78000000 if VMSPLIT_2G_OPT
1465 default 0x40000000 if VMSPLIT_1G
1466 default 0xC0000000
1467 depends on X86_32
1468
1469config HIGHMEM
3c2362e6 1470 def_bool y
506f1d07 1471 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1472
1473config X86_PAE
9ba16087 1474 bool "PAE (Physical Address Extension) Support"
88a2b4ed 1475 depends on X86_32 && X86_HAVE_PAE
d4a451d5 1476 select PHYS_ADDR_T_64BIT
9d99c712 1477 select SWIOTLB
a7f7f624 1478 help
506f1d07
SR
1479 PAE is required for NX support, and furthermore enables
1480 larger swapspace support for non-overcommit purposes. It
1481 has the cost of more pagetable lookup overhead, and also
1482 consumes more pagetable space per process.
1483
77ef56e4
KS
1484config X86_5LEVEL
1485 bool "Enable 5-level page tables support"
18ec1eaf 1486 default y
eedb92ab 1487 select DYNAMIC_MEMORY_LAYOUT
162434e7 1488 select SPARSEMEM_VMEMMAP
77ef56e4 1489 depends on X86_64
a7f7f624 1490 help
77ef56e4 1491 5-level paging enables access to larger address space:
54628de6 1492 up to 128 PiB of virtual address space and 4 PiB of
77ef56e4
KS
1493 physical address space.
1494
1495 It will be supported by future Intel CPUs.
1496
6657fca0
KS
1497 A kernel with the option enabled can be booted on machines that
1498 support 4- or 5-level paging.
77ef56e4 1499
ff61f079 1500 See Documentation/arch/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1501 information.
1502
1503 Say N if unsure.
1504
10971ab2 1505config X86_DIRECT_GBPAGES
e5008abe 1506 def_bool y
2e1da13f 1507 depends on X86_64
a7f7f624 1508 help
10971ab2
IM
1509 Certain kernel features effectively disable kernel
1510 linear 1 GB mappings (even if the CPU otherwise
1511 supports them), so don't confuse the user by printing
1512 that we have them enabled.
9e899816 1513
5c280cf6
TG
1514config X86_CPA_STATISTICS
1515 bool "Enable statistic for Change Page Attribute"
1516 depends on DEBUG_FS
a7f7f624 1517 help
b75baaf3 1518 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1519 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1520 page mappings when mapping protections are changed.
1521
20f07a04
KS
1522config X86_MEM_ENCRYPT
1523 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1524 select DYNAMIC_PHYSICAL_MASK
20f07a04
KS
1525 def_bool n
1526
7744ccdb
TL
1527config AMD_MEM_ENCRYPT
1528 bool "AMD Secure Memory Encryption (SME) support"
1529 depends on X86_64 && CPU_SUP_AMD
6c321179 1530 depends on EFI_STUB
82fef0ad 1531 select DMA_COHERENT_POOL
ce9084ba 1532 select ARCH_USE_MEMREMAP_PROT
597cfe48 1533 select INSTRUCTION_DECODER
aa5a4611 1534 select ARCH_HAS_CC_PLATFORM
20f07a04 1535 select X86_MEM_ENCRYPT
6c321179 1536 select UNACCEPTED_MEMORY
a7f7f624 1537 help
7744ccdb
TL
1538 Say yes to enable support for the encryption of system memory.
1539 This requires an AMD processor that supports Secure Memory
1540 Encryption (SME).
1541
1542config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1543 bool "Activate AMD Secure Memory Encryption (SME) by default"
7744ccdb 1544 depends on AMD_MEM_ENCRYPT
a7f7f624 1545 help
7744ccdb
TL
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
e133f6ea 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
7ecd19cf 1561 select USE_PERCPU_NUMA_NODE_ID
0c436a58 1562 select OF_NUMA if OF
a7f7f624 1563 help
e133f6ea 1564 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1565
506f1d07
SR
1566 The kernel will try to allocate memory used by a CPU on the
1567 local memory controller of the CPU and add some more
1568 NUMA awareness to the kernel.
1569
c280ea5e 1570 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1571 (or later), AMD Opteron, or EM64T NUMA.
1572
b5660ba7 1573 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1574 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1575
1576 Otherwise, you should say N.
506f1d07 1577
eec1d4fa 1578config AMD_NUMA
3c2362e6
HH
1579 def_bool y
1580 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1581 depends on X86_64 && NUMA && PCI
a7f7f624 1582 help
eec1d4fa
HR
1583 Enable AMD NUMA node topology detection. You should say Y here if
1584 you have a multi processor AMD system. This uses an old method to
1585 read the NUMA configuration directly from the builtin Northbridge
1586 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1587 which also takes priority if both are compiled in.
506f1d07
SR
1588
1589config X86_64_ACPI_NUMA
3c2362e6
HH
1590 def_bool y
1591 prompt "ACPI NUMA detection"
506f1d07
SR
1592 depends on X86_64 && NUMA && ACPI && PCI
1593 select ACPI_NUMA
a7f7f624 1594 help
506f1d07
SR
1595 Enable ACPI SRAT based node topology detection.
1596
1597config NUMA_EMU
1598 bool "NUMA emulation"
1b7e03ef 1599 depends on NUMA
a7f7f624 1600 help
506f1d07
SR
1601 Enable NUMA emulation. A flat machine will be split
1602 into virtual nodes when booted with "numa=fake=N", where N is the
1603 number of nodes. This is only useful for debugging.
1604
1605config NODES_SHIFT
d25e26b6 1606 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1607 range 1 10
1608 default "10" if MAXSMP
506f1d07 1609 default "6" if X86_64
506f1d07 1610 default "3"
a9ee6cf5 1611 depends on NUMA
a7f7f624 1612 help
1184dc2f 1613 Specify the maximum number of NUMA Nodes available on the target
692105b8 1614 system. Increases memory reserved to accommodate various tables.
506f1d07 1615
506f1d07
SR
1616config ARCH_FLATMEM_ENABLE
1617 def_bool y
3b16651f 1618 depends on X86_32 && !NUMA
506f1d07 1619
506f1d07
SR
1620config ARCH_SPARSEMEM_ENABLE
1621 def_bool y
6ea30386 1622 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1623 select SPARSEMEM_STATIC if X86_32
1624 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1625
3b16651f 1626config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1627 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1628
506f1d07
SR
1629config ARCH_SELECT_MEMORY_MODEL
1630 def_bool y
4eda2bc3 1631 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
506f1d07
SR
1632
1633config ARCH_MEMORY_PROBE
a0842b70 1634 bool "Enable sysfs memory/probe interface"
5c11f00b 1635 depends on MEMORY_HOTPLUG
a0842b70
TK
1636 help
1637 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1638 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1639 If you are unsure how to answer this question, answer N.
506f1d07 1640
3b16651f
TH
1641config ARCH_PROC_KCORE_TEXT
1642 def_bool y
1643 depends on X86_64 && PROC_KCORE
1644
a29815a3 1645config ILLEGAL_POINTER_VALUE
b03b016f
KK
1646 hex
1647 default 0 if X86_32
1648 default 0xdead000000000000 if X86_64
a29815a3 1649
7a67832c
DW
1650config X86_PMEM_LEGACY_DEVICE
1651 bool
1652
ec776ef6 1653config X86_PMEM_LEGACY
7a67832c 1654 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1655 depends on PHYS_ADDR_T_64BIT
1656 depends on BLK_DEV
7a67832c 1657 select X86_PMEM_LEGACY_DEVICE
7b27a862 1658 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1659 select LIBNVDIMM
ec776ef6
CH
1660 help
1661 Treat memory marked using the non-standard e820 type of 12 as used
1662 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1663 The kernel will offer these regions to the 'pmem' driver so
1664 they can be used for persistent storage.
1665
1666 Say Y if unsure.
1667
506f1d07
SR
1668config HIGHPTE
1669 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1670 depends on HIGHMEM
a7f7f624 1671 help
506f1d07
SR
1672 The VM uses one page table entry for each page of physical memory.
1673 For systems with a lot of RAM, this can be wasteful of precious
1674 low memory. Setting this option will put user-space page table
1675 entries in high memory.
1676
9f077871 1677config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1678 bool "Check for low memory corruption"
a7f7f624 1679 help
8f9ca475
IM
1680 Periodically check for memory corruption in low memory, which
1681 is suspected to be caused by BIOS. Even when enabled in the
1682 configuration, it is disabled at runtime. Enable it by
1683 setting "memory_corruption_check=1" on the kernel command
1684 line. By default it scans the low 64k of memory every 60
1685 seconds; see the memory_corruption_check_size and
1686 memory_corruption_check_period parameters in
8c27ceff 1687 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1688
1689 When enabled with the default parameters, this option has
1690 almost no overhead, as it reserves a relatively small amount
1691 of memory and scans it infrequently. It both detects corruption
1692 and prevents it from affecting the running system.
1693
1694 It is, however, intended as a diagnostic tool; if repeatable
1695 BIOS-originated corruption always affects the same memory,
1696 you can use memmap= to prevent the kernel from using that
1697 memory.
9f077871 1698
c885df50 1699config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1700 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1701 depends on X86_CHECK_BIOS_CORRUPTION
1702 default y
a7f7f624 1703 help
8f9ca475
IM
1704 Set whether the default state of memory_corruption_check is
1705 on or off.
c885df50 1706
506f1d07
SR
1707config MATH_EMULATION
1708 bool
a5b9e5a2 1709 depends on MODIFY_LDT_SYSCALL
87d6021b 1710 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1711 help
506f1d07
SR
1712 Linux can emulate a math coprocessor (used for floating point
1713 operations) if you don't have one. 486DX and Pentium processors have
1714 a math coprocessor built in, 486SX and 386 do not, unless you added
1715 a 487DX or 387, respectively. (The messages during boot time can
1716 give you some hints here ["man dmesg"].) Everyone needs either a
1717 coprocessor or this emulation.
1718
1719 If you don't have a math coprocessor, you need to say Y here; if you
1720 say Y here even though you have a coprocessor, the coprocessor will
1721 be used nevertheless. (This behavior can be changed with the kernel
1722 command line option "no387", which comes handy if your coprocessor
1723 is broken. Try "man bootparam" or see the documentation of your boot
1724 loader (lilo or loadlin) about how to pass options to the kernel at
1725 boot time.) This means that it is a good idea to say Y here if you
1726 intend to use this kernel on different machines.
1727
1728 More information about the internals of the Linux math coprocessor
1729 emulation can be found in <file:arch/x86/math-emu/README>.
1730
1731 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1732 kernel, it won't hurt.
1733
1734config MTRR
6fc108a0 1735 def_bool y
6a108a14 1736 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1737 help
506f1d07
SR
1738 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1739 the Memory Type Range Registers (MTRRs) may be used to control
1740 processor access to memory ranges. This is most useful if you have
1741 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1742 allows bus write transfers to be combined into a larger transfer
1743 before bursting over the PCI/AGP bus. This can increase performance
1744 of image write operations 2.5 times or more. Saying Y here creates a
1745 /proc/mtrr file which may be used to manipulate your processor's
1746 MTRRs. Typically the X server should use this.
1747
1748 This code has a reasonably generic interface so that similar
1749 control registers on other processors can be easily supported
1750 as well:
1751
1752 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1753 Registers (ARRs) which provide a similar functionality to MTRRs. For
1754 these, the ARRs are used to emulate the MTRRs.
1755 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1756 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1757 write-combining. All of these processors are supported by this code
1758 and it makes sense to say Y here if you have one of them.
1759
1760 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1761 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1762 can lead to all sorts of problems, so it's good to say Y here.
1763
1764 You can safely say Y even if your machine doesn't have MTRRs, you'll
1765 just add about 9 KB to your kernel.
1766
ff61f079 1767 See <file:Documentation/arch/x86/mtrr.rst> for more information.
506f1d07 1768
95ffa243 1769config MTRR_SANITIZER
2ffb3501 1770 def_bool y
95ffa243
YL
1771 prompt "MTRR cleanup support"
1772 depends on MTRR
a7f7f624 1773 help
aba3728c
TG
1774 Convert MTRR layout from continuous to discrete, so X drivers can
1775 add writeback entries.
95ffa243 1776
aba3728c 1777 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1778 The largest mtrr entry size for a continuous block can be set with
aba3728c 1779 mtrr_chunk_size.
95ffa243 1780
2ffb3501 1781 If unsure, say Y.
95ffa243
YL
1782
1783config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1784 int "MTRR cleanup enable value (0-1)"
1785 range 0 1
1786 default "0"
95ffa243 1787 depends on MTRR_SANITIZER
a7f7f624 1788 help
f5098d62 1789 Enable mtrr cleanup default value
95ffa243 1790
12031a62
YL
1791config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1792 int "MTRR cleanup spare reg num (0-7)"
1793 range 0 7
1794 default "1"
1795 depends on MTRR_SANITIZER
a7f7f624 1796 help
12031a62 1797 mtrr cleanup spare entries default, it can be changed via
aba3728c 1798 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1799
2e5d9c85 1800config X86_PAT
6fc108a0 1801 def_bool y
6a108a14 1802 prompt "x86 PAT support" if EXPERT
2a8a2719 1803 depends on MTRR
a7f7f624 1804 help
2e5d9c85 1805 Use PAT attributes to setup page level cache control.
042b78e4 1806
2e5d9c85 1807 PATs are the modern equivalents of MTRRs and are much more
1808 flexible than MTRRs.
1809
1810 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1811 spontaneous reboots) or a non-working video driver.
2e5d9c85 1812
1813 If unsure, say Y.
1814
46cf98cd
VP
1815config ARCH_USES_PG_UNCACHED
1816 def_bool y
1817 depends on X86_PAT
1818
b971880f 1819config X86_UMIP
796ebc81 1820 def_bool y
b971880f 1821 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1822 help
b971880f
BM
1823 User Mode Instruction Prevention (UMIP) is a security feature in
1824 some x86 processors. If enabled, a general protection fault is
1825 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1826 executed in user mode. These instructions unnecessarily expose
1827 information about the hardware state.
796ebc81
RN
1828
1829 The vast majority of applications do not use these instructions.
1830 For the very few that do, software emulation is provided in
1831 specific cases in protected and virtual-8086 modes. Emulated
1832 results are dummy.
aa35f896 1833
156ff4a5
PZ
1834config CC_HAS_IBT
1835 # GCC >= 9 and binutils >= 2.29
1836 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1837 # Clang/LLVM >= 14
262448f3
NC
1838 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1839 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
156ff4a5 1840 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
262448f3 1841 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
156ff4a5
PZ
1842 $(as-instr,endbr64)
1843
18e66b69
RE
1844config X86_CET
1845 def_bool n
1846 help
1847 CET features configured (Shadow stack or IBT)
1848
156ff4a5
PZ
1849config X86_KERNEL_IBT
1850 prompt "Indirect Branch Tracking"
4fd5f70c 1851 def_bool y
03f16cd0 1852 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
f6a2c2b2
NC
1853 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1854 depends on !LD_IS_LLD || LLD_VERSION >= 140000
03f16cd0 1855 select OBJTOOL
18e66b69 1856 select X86_CET
156ff4a5
PZ
1857 help
1858 Build the kernel with support for Indirect Branch Tracking, a
1859 hardware support course-grain forward-edge Control Flow Integrity
1860 protection. It enforces that all indirect calls must land on
1861 an ENDBR instruction, as such, the compiler will instrument the
1862 code with them to make this happen.
1863
ed53a0d9 1864 In addition to building the kernel with IBT, seal all functions that
4cdfc11b 1865 are not indirect call targets, avoiding them ever becoming one.
ed53a0d9
PZ
1866
1867 This requires LTO like objtool runs and will slow down the build. It
1868 does significantly reduce the number of ENDBR instructions in the
1869 kernel image.
1870
35e97790 1871config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1872 prompt "Memory Protection Keys"
35e97790 1873 def_bool y
284244a9 1874 # Note: only available in 64-bit mode
38f3e775 1875 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1876 select ARCH_USES_HIGH_VMA_FLAGS
1877 select ARCH_HAS_PKEYS
a7f7f624 1878 help
284244a9
DH
1879 Memory Protection Keys provides a mechanism for enforcing
1880 page-based protections, but without requiring modification of the
1881 page tables when an application changes protection domains.
1882
1eecbcdc 1883 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1884
1885 If unsure, say y.
35e97790 1886
db616173
MH
1887choice
1888 prompt "TSX enable mode"
1889 depends on CPU_SUP_INTEL
1890 default X86_INTEL_TSX_MODE_OFF
1891 help
1892 Intel's TSX (Transactional Synchronization Extensions) feature
1893 allows to optimize locking protocols through lock elision which
1894 can lead to a noticeable performance boost.
1895
1896 On the other hand it has been shown that TSX can be exploited
1897 to form side channel attacks (e.g. TAA) and chances are there
1898 will be more of those attacks discovered in the future.
1899
1900 Therefore TSX is not enabled by default (aka tsx=off). An admin
1901 might override this decision by tsx=on the command line parameter.
1902 Even with TSX enabled, the kernel will attempt to enable the best
1903 possible TAA mitigation setting depending on the microcode available
1904 for the particular machine.
1905
1906 This option allows to set the default tsx mode between tsx=on, =off
1907 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1908 details.
1909
1910 Say off if not sure, auto if TSX is in use but it should be used on safe
1911 platforms or on if TSX is in use and the security aspect of tsx is not
1912 relevant.
1913
1914config X86_INTEL_TSX_MODE_OFF
1915 bool "off"
1916 help
1917 TSX is disabled if possible - equals to tsx=off command line parameter.
1918
1919config X86_INTEL_TSX_MODE_ON
1920 bool "on"
1921 help
1922 TSX is always enabled on TSX capable HW - equals the tsx=on command
1923 line parameter.
1924
1925config X86_INTEL_TSX_MODE_AUTO
1926 bool "auto"
1927 help
1928 TSX is enabled on TSX capable HW that is believed to be safe against
1929 side channel attacks- equals the tsx=auto command line parameter.
1930endchoice
1931
e7e05452
SC
1932config X86_SGX
1933 bool "Software Guard eXtensions (SGX)"
b8d1d163 1934 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
e7e05452
SC
1935 depends on CRYPTO=y
1936 depends on CRYPTO_SHA256=y
e7e05452 1937 select MMU_NOTIFIER
901ddbb9 1938 select NUMA_KEEP_MEMINFO if NUMA
40e0e784 1939 select XARRAY_MULTI
e7e05452
SC
1940 help
1941 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1942 that can be used by applications to set aside private regions of code
1943 and data, referred to as enclaves. An enclave's private memory can
1944 only be accessed by code running within the enclave. Accesses from
1945 outside the enclave, including other enclaves, are disallowed by
1946 hardware.
1947
1948 If unsure, say N.
1949
18e66b69
RE
1950config X86_USER_SHADOW_STACK
1951 bool "X86 userspace shadow stack"
1952 depends on AS_WRUSS
1953 depends on X86_64
1954 select ARCH_USES_HIGH_VMA_FLAGS
1955 select X86_CET
1956 help
1957 Shadow stack protection is a hardware feature that detects function
1958 return address corruption. This helps mitigate ROP attacks.
1959 Applications must be enabled to use it, and old userspace does not
1960 get protection "for free".
1961
1962 CPUs supporting shadow stacks were first released in 2020.
1963
54acee60 1964 See Documentation/arch/x86/shstk.rst for more information.
18e66b69
RE
1965
1966 If unsure, say N.
1967
c33621b4
KH
1968config INTEL_TDX_HOST
1969 bool "Intel Trust Domain Extensions (TDX) host support"
1970 depends on CPU_SUP_INTEL
1971 depends on X86_64
1972 depends on KVM_INTEL
3115cabd 1973 depends on X86_X2APIC
abe8dbab 1974 select ARCH_KEEP_MEMBLOCK
ac3a2208 1975 depends on CONTIG_ALLOC
cb8eb06d 1976 depends on !KEXEC_CORE
83e1bdc9 1977 depends on X86_MCE
c33621b4
KH
1978 help
1979 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1980 host and certain physical attacks. This option enables necessary TDX
1981 support in the host kernel to run confidential VMs.
1982
1983 If unsure, say N.
1984
506f1d07 1985config EFI
9ba16087 1986 bool "EFI runtime service support"
5b83683f 1987 depends on ACPI
f6ce5002 1988 select UCS2_STRING
022ee6c5 1989 select EFI_RUNTIME_WRAPPERS
1ff2fc02 1990 select ARCH_USE_MEMREMAP_PROT
aba7e066 1991 select EFI_RUNTIME_MAP if KEXEC_CORE
a7f7f624 1992 help
8f9ca475
IM
1993 This enables the kernel to use EFI runtime services that are
1994 available (such as the EFI variable services).
506f1d07 1995
8f9ca475
IM
1996 This option is only useful on systems that have EFI firmware.
1997 In addition, you should use the latest ELILO loader available
1998 at <http://elilo.sourceforge.net> in order to take advantage
1999 of EFI runtime services. However, even with this option, the
2000 resultant kernel should continue to boot on existing non-EFI
2001 platforms.
506f1d07 2002
291f3632 2003config EFI_STUB
8f24f8c2 2004 bool "EFI stub support"
c6dbd3e5 2005 depends on EFI
8f24f8c2 2006 select RELOCATABLE
a7f7f624 2007 help
8f24f8c2 2008 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
2009 by EFI firmware without the use of a bootloader.
2010
4f4cfa6c 2011 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 2012
cc3fdda2
AB
2013config EFI_HANDOVER_PROTOCOL
2014 bool "EFI handover protocol (DEPRECATED)"
2015 depends on EFI_STUB
2016 default y
2017 help
2018 Select this in order to include support for the deprecated EFI
2019 handover protocol, which defines alternative entry points into the
2020 EFI stub. This is a practice that has no basis in the UEFI
2021 specification, and requires a priori knowledge on the part of the
2022 bootloader about Linux/x86 specific ways of passing the command line
2023 and initrd, and where in memory those assets may be loaded.
2024
2025 If in doubt, say Y. Even though the corresponding support is not
2026 present in upstream GRUB or other bootloaders, most distros build
2027 GRUB with numerous downstream patches applied, and may rely on the
2028 handover protocol as as result.
2029
7d453eee
MF
2030config EFI_MIXED
2031 bool "EFI mixed-mode support"
2032 depends on EFI_STUB && X86_64
a7f7f624 2033 help
758cd94a
JH
2034 Enabling this feature allows a 64-bit kernel to be booted
2035 on a 32-bit firmware, provided that your CPU supports 64-bit
2036 mode.
7d453eee 2037
758cd94a
JH
2038 Note that it is not possible to boot a mixed-mode enabled
2039 kernel via the EFI boot stub - a bootloader that supports
2040 the EFI handover protocol must be used.
7d453eee 2041
758cd94a 2042 If unsure, say N.
7d453eee 2043
4059ba65
AB
2044config EFI_FAKE_MEMMAP
2045 bool "Enable EFI fake memory map"
2046 depends on EFI
2047 help
2048 Saying Y here will enable "efi_fake_mem" boot option. By specifying
2049 this parameter, you can add arbitrary attribute to specific memory
2050 range by updating original (firmware provided) EFI memmap. This is
2051 useful for debugging of EFI memmap related feature, e.g., Address
2052 Range Mirroring feature.
2053
2054config EFI_MAX_FAKE_MEM
2055 int "maximum allowable number of ranges in efi_fake_mem boot option"
2056 depends on EFI_FAKE_MEMMAP
2057 range 1 128
2058 default 8
2059 help
2060 Maximum allowable number of ranges in efi_fake_mem boot option.
2061 Ranges can be set up to this value using comma-separated list.
2062 The default value is 8.
2063
1fff234d
AB
2064config EFI_RUNTIME_MAP
2065 bool "Export EFI runtime maps to sysfs" if EXPERT
2066 depends on EFI
1fff234d
AB
2067 help
2068 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2069 That memory map is required by the 2nd kernel to set up EFI virtual
2070 mappings after kexec, but can also be used for debugging purposes.
2071
2072 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2073
8636a1f9 2074source "kernel/Kconfig.hz"
506f1d07 2075
6af51380
ED
2076config ARCH_SUPPORTS_KEXEC
2077 def_bool y
74ca317c 2078
6af51380 2079config ARCH_SUPPORTS_KEXEC_FILE
c1ad12ee 2080 def_bool X86_64
b799a09f 2081
6af51380
ED
2082config ARCH_SELECTS_KEXEC_FILE
2083 def_bool y
74ca317c 2084 depends on KEXEC_FILE
6af51380 2085 select HAVE_IMA_KEXEC if IMA
d8eb8940 2086
e6265fe7 2087config ARCH_SUPPORTS_KEXEC_PURGATORY
c1ad12ee 2088 def_bool y
99d5cadf 2089
6af51380
ED
2090config ARCH_SUPPORTS_KEXEC_SIG
2091 def_bool y
8e7d8381 2092
6af51380
ED
2093config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2094 def_bool y
99d5cadf 2095
6af51380
ED
2096config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2097 def_bool y
8e7d8381 2098
6af51380
ED
2099config ARCH_SUPPORTS_KEXEC_JUMP
2100 def_bool y
506f1d07 2101
6af51380
ED
2102config ARCH_SUPPORTS_CRASH_DUMP
2103 def_bool X86_64 || (X86_32 && HIGHMEM)
3ab83521 2104
ea53ad9c
ED
2105config ARCH_SUPPORTS_CRASH_HOTPLUG
2106 def_bool y
3ab83521 2107
9c08a2a1
BH
2108config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2109 def_bool CRASH_CORE
2110
506f1d07 2111config PHYSICAL_START
6a108a14 2112 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2113 default "0x1000000"
a7f7f624 2114 help
506f1d07
SR
2115 This gives the physical address where the kernel is loaded.
2116
2117 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2118 bzImage will decompress itself to above physical address and
2119 run from there. Otherwise, bzImage will run from the address where
2120 it has been loaded by the boot loader and will ignore above physical
2121 address.
2122
2123 In normal kdump cases one does not have to set/change this option
2124 as now bzImage can be compiled as a completely relocatable image
2125 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2126 address. This option is mainly useful for the folks who don't want
2127 to use a bzImage for capturing the crash dump and want to use a
2128 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2129 to be specifically compiled to run from a specific memory area
2130 (normally a reserved region) and this option comes handy.
2131
ceefccc9
PA
2132 So if you are using bzImage for capturing the crash dump,
2133 leave the value here unchanged to 0x1000000 and set
2134 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2135 for capturing the crash dump change this value to start of
2136 the reserved region. In other words, it can be set based on
2137 the "X" value as specified in the "crashkernel=YM@XM"
2138 command line boot parameter passed to the panic-ed
330d4810 2139 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2140 for more details about crash dumps.
506f1d07
SR
2141
2142 Usage of bzImage for capturing the crash dump is recommended as
2143 one does not have to build two kernels. Same kernel can be used
2144 as production kernel and capture kernel. Above option should have
2145 gone away after relocatable bzImage support is introduced. But it
2146 is present because there are users out there who continue to use
2147 vmlinux for dump capture. This option should go away down the
2148 line.
2149
2150 Don't change this unless you know what you are doing.
2151
2152config RELOCATABLE
26717808
PA
2153 bool "Build a relocatable kernel"
2154 default y
a7f7f624 2155 help
506f1d07
SR
2156 This builds a kernel image that retains relocation information
2157 so it can be loaded someplace besides the default 1MB.
2158 The relocations tend to make the kernel binary about 10% larger,
2159 but are discarded at runtime.
2160
2161 One use is for the kexec on panic case where the recovery kernel
2162 must live at a different physical address than the primary
2163 kernel.
2164
2165 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2166 it has been loaded at and the compile time physical address
8ab3820f 2167 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2168
8ab3820f 2169config RANDOMIZE_BASE
e8581e3d 2170 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2171 depends on RELOCATABLE
6807c846 2172 default y
a7f7f624 2173 help
e8581e3d
BH
2174 In support of Kernel Address Space Layout Randomization (KASLR),
2175 this randomizes the physical address at which the kernel image
2176 is decompressed and the virtual address where the kernel
2177 image is mapped, as a security feature that deters exploit
2178 attempts relying on knowledge of the location of kernel
2179 code internals.
2180
ed9f007e
KC
2181 On 64-bit, the kernel physical and virtual addresses are
2182 randomized separately. The physical address will be anywhere
2183 between 16MB and the top of physical memory (up to 64TB). The
2184 virtual address will be randomized from 16MB up to 1GB (9 bits
2185 of entropy). Note that this also reduces the memory space
2186 available to kernel modules from 1.5GB to 1GB.
2187
2188 On 32-bit, the kernel physical and virtual addresses are
2189 randomized together. They will be randomized from 16MB up to
2190 512MB (8 bits of entropy).
e8581e3d
BH
2191
2192 Entropy is generated using the RDRAND instruction if it is
2193 supported. If RDTSC is supported, its value is mixed into
2194 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2195 supported, then entropy is read from the i8254 timer. The
2196 usable entropy is limited by the kernel being built using
2197 2GB addressing, and that PHYSICAL_ALIGN must be at a
2198 minimum of 2MB. As a result, only 10 bits of entropy are
2199 theoretically possible, but the implementations are further
2200 limited due to memory layouts.
e8581e3d 2201
6807c846 2202 If unsure, say Y.
8ab3820f
KC
2203
2204# Relocation on x86 needs some additional build support
845adf72
PA
2205config X86_NEED_RELOCS
2206 def_bool y
8ab3820f 2207 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2208
506f1d07 2209config PHYSICAL_ALIGN
a0215061 2210 hex "Alignment value to which kernel should be aligned"
8ab3820f 2211 default "0x200000"
a0215061
KC
2212 range 0x2000 0x1000000 if X86_32
2213 range 0x200000 0x1000000 if X86_64
a7f7f624 2214 help
506f1d07
SR
2215 This value puts the alignment restrictions on physical address
2216 where kernel is loaded and run from. Kernel is compiled for an
2217 address which meets above alignment restriction.
2218
2219 If bootloader loads the kernel at a non-aligned address and
2220 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2221 address aligned to above value and run from there.
2222
2223 If bootloader loads the kernel at a non-aligned address and
2224 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2225 load address and decompress itself to the address it has been
2226 compiled for and run from there. The address for which kernel is
2227 compiled already meets above alignment restrictions. Hence the
2228 end result is that kernel runs from a physical address meeting
2229 above alignment restrictions.
2230
a0215061
KC
2231 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2232 this value must be a multiple of 0x200000.
2233
506f1d07
SR
2234 Don't change this unless you know what you are doing.
2235
eedb92ab
KS
2236config DYNAMIC_MEMORY_LAYOUT
2237 bool
a7f7f624 2238 help
eedb92ab
KS
2239 This option makes base addresses of vmalloc and vmemmap as well as
2240 __PAGE_OFFSET movable during boot.
2241
0483e1fa
TG
2242config RANDOMIZE_MEMORY
2243 bool "Randomize the kernel memory sections"
2244 depends on X86_64
2245 depends on RANDOMIZE_BASE
eedb92ab 2246 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2247 default RANDOMIZE_BASE
a7f7f624 2248 help
758cd94a
JH
2249 Randomizes the base virtual address of kernel memory sections
2250 (physical memory mapping, vmalloc & vmemmap). This security feature
2251 makes exploits relying on predictable memory locations less reliable.
0483e1fa 2252
758cd94a
JH
2253 The order of allocations remains unchanged. Entropy is generated in
2254 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2255 configuration have in average 30,000 different possible virtual
2256 addresses for each memory section.
0483e1fa 2257
758cd94a 2258 If unsure, say Y.
0483e1fa 2259
90397a41
TG
2260config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2261 hex "Physical memory mapping padding" if EXPERT
2262 depends on RANDOMIZE_MEMORY
2263 default "0xa" if MEMORY_HOTPLUG
2264 default "0x0"
2265 range 0x1 0x40 if MEMORY_HOTPLUG
2266 range 0x0 0x40
a7f7f624 2267 help
758cd94a
JH
2268 Define the padding in terabytes added to the existing physical
2269 memory size during kernel memory randomization. It is useful
2270 for memory hotplug support but reduces the entropy available for
2271 address randomization.
90397a41 2272
758cd94a 2273 If unsure, leave at the default value.
90397a41 2274
6449dcb0
KS
2275config ADDRESS_MASKING
2276 bool "Linear Address Masking support"
2277 depends on X86_64
2278 help
2279 Linear Address Masking (LAM) modifies the checking that is applied
2280 to 64-bit linear addresses, allowing software to use of the
2281 untranslated address bits for metadata.
2282
2283 The capability can be used for efficient address sanitizers (ASAN)
2284 implementation and for optimizations in JITs.
2285
506f1d07 2286config HOTPLUG_CPU
bebd024e 2287 def_bool y
40b31360 2288 depends on SMP
506f1d07
SR
2289
2290config COMPAT_VDSO
b0b49f26
AL
2291 def_bool n
2292 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2293 depends on COMPAT_32
a7f7f624 2294 help
b0b49f26
AL
2295 Certain buggy versions of glibc will crash if they are
2296 presented with a 32-bit vDSO that is not mapped at the address
2297 indicated in its segment table.
e84446de 2298
b0b49f26
AL
2299 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2300 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2301 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2302 the only released version with the bug, but OpenSUSE 9
2303 contains a buggy "glibc 2.3.2".
506f1d07 2304
b0b49f26
AL
2305 The symptom of the bug is that everything crashes on startup, saying:
2306 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2307
2308 Saying Y here changes the default value of the vdso32 boot
2309 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2310 This works around the glibc bug but hurts performance.
2311
2312 If unsure, say N: if you are compiling your own kernel, you
2313 are unlikely to be using a buggy version of glibc.
506f1d07 2314
3dc33bd3
KC
2315choice
2316 prompt "vsyscall table for legacy applications"
2317 depends on X86_64
625b7b7f 2318 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2319 help
2320 Legacy user code that does not know how to find the vDSO expects
2321 to be able to issue three syscalls by calling fixed addresses in
2322 kernel space. Since this location is not randomized with ASLR,
2323 it can be used to assist security vulnerability exploitation.
2324
2325 This setting can be changed at boot time via the kernel command
bf00745e
AL
2326 line parameter vsyscall=[emulate|xonly|none]. Emulate mode
2327 is deprecated and can only be enabled using the kernel command
2328 line.
3dc33bd3
KC
2329
2330 On a system with recent enough glibc (2.14 or newer) and no
2331 static binaries, you can say None without a performance penalty
2332 to improve security.
2333
bd49e16e 2334 If unsure, select "Emulate execution only".
3dc33bd3 2335
bd49e16e
AL
2336 config LEGACY_VSYSCALL_XONLY
2337 bool "Emulate execution only"
2338 help
2339 The kernel traps and emulates calls into the fixed vsyscall
2340 address mapping and does not allow reads. This
2341 configuration is recommended when userspace might use the
2342 legacy vsyscall area but support for legacy binary
2343 instrumentation of legacy code is not needed. It mitigates
2344 certain uses of the vsyscall area as an ASLR-bypassing
2345 buffer.
3dc33bd3
KC
2346
2347 config LEGACY_VSYSCALL_NONE
2348 bool "None"
2349 help
2350 There will be no vsyscall mapping at all. This will
2351 eliminate any risk of ASLR bypass due to the vsyscall
2352 fixed address mapping. Attempts to use the vsyscalls
2353 will be reported to dmesg, so that either old or
2354 malicious userspace programs can be identified.
2355
2356endchoice
2357
516cbf37
TB
2358config CMDLINE_BOOL
2359 bool "Built-in kernel command line"
a7f7f624 2360 help
516cbf37
TB
2361 Allow for specifying boot arguments to the kernel at
2362 build time. On some systems (e.g. embedded ones), it is
2363 necessary or convenient to provide some or all of the
2364 kernel boot arguments with the kernel itself (that is,
2365 to not rely on the boot loader to provide them.)
2366
2367 To compile command line arguments into the kernel,
2368 set this option to 'Y', then fill in the
69711ca1 2369 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2370
2371 Systems with fully functional boot loaders (i.e. non-embedded)
2372 should leave this option set to 'N'.
2373
2374config CMDLINE
2375 string "Built-in kernel command string"
2376 depends on CMDLINE_BOOL
2377 default ""
a7f7f624 2378 help
516cbf37
TB
2379 Enter arguments here that should be compiled into the kernel
2380 image and used at boot time. If the boot loader provides a
2381 command line at boot time, it is appended to this string to
2382 form the full kernel command line, when the system boots.
2383
2384 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2385 change this behavior.
2386
2387 In most cases, the command line (whether built-in or provided
2388 by the boot loader) should specify the device for the root
2389 file system.
2390
2391config CMDLINE_OVERRIDE
2392 bool "Built-in command line overrides boot loader arguments"
645e6466 2393 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2394 help
516cbf37
TB
2395 Set this option to 'Y' to have the kernel ignore the boot loader
2396 command line, and use ONLY the built-in command line.
2397
2398 This is used to work around broken boot loaders. This should
2399 be set to 'N' under normal conditions.
2400
a5b9e5a2
AL
2401config MODIFY_LDT_SYSCALL
2402 bool "Enable the LDT (local descriptor table)" if EXPERT
2403 default y
a7f7f624 2404 help
a5b9e5a2
AL
2405 Linux can allow user programs to install a per-process x86
2406 Local Descriptor Table (LDT) using the modify_ldt(2) system
2407 call. This is required to run 16-bit or segmented code such as
2408 DOSEMU or some Wine programs. It is also used by some very old
2409 threading libraries.
2410
2411 Enabling this feature adds a small amount of overhead to
2412 context switches and increases the low-level kernel attack
2413 surface. Disabling it removes the modify_ldt(2) system call.
2414
2415 Saying 'N' here may make sense for embedded or server kernels.
2416
3aac3ebe
TG
2417config STRICT_SIGALTSTACK_SIZE
2418 bool "Enforce strict size checking for sigaltstack"
2419 depends on DYNAMIC_SIGFRAME
2420 help
2421 For historical reasons MINSIGSTKSZ is a constant which became
2422 already too small with AVX512 support. Add a mechanism to
2423 enforce strict checking of the sigaltstack size against the
2424 real size of the FPU frame. This option enables the check
2425 by default. It can also be controlled via the kernel command
2426 line option 'strict_sas_size' independent of this config
2427 switch. Enabling it might break existing applications which
2428 allocate a too small sigaltstack but 'work' because they
2429 never get a signal delivered.
2430
2431 Say 'N' unless you want to really enforce this check.
2432
b700e7f0
SJ
2433source "kernel/livepatch/Kconfig"
2434
506f1d07
SR
2435endmenu
2436
f43b9876
PZ
2437config CC_HAS_SLS
2438 def_bool $(cc-option,-mharden-sls=all)
2439
2440config CC_HAS_RETURN_THUNK
2441 def_bool $(cc-option,-mfunction-return=thunk-extern)
2442
bea75b33
TG
2443config CC_HAS_ENTRY_PADDING
2444 def_bool $(cc-option,-fpatchable-function-entry=16,16)
2445
2446config FUNCTION_PADDING_CFI
2447 int
2448 default 59 if FUNCTION_ALIGNMENT_64B
2449 default 27 if FUNCTION_ALIGNMENT_32B
2450 default 11 if FUNCTION_ALIGNMENT_16B
2451 default 3 if FUNCTION_ALIGNMENT_8B
2452 default 0
2453
2454# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2455# except Kconfig can't do arithmetic :/
2456config FUNCTION_PADDING_BYTES
2457 int
2458 default FUNCTION_PADDING_CFI if CFI_CLANG
2459 default FUNCTION_ALIGNMENT
2460
931ab636
PZ
2461config CALL_PADDING
2462 def_bool n
2463 depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2464 select FUNCTION_ALIGNMENT_16B
2465
2466config FINEIBT
2467 def_bool y
2468 depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE
2469 select CALL_PADDING
2470
8f7c0d8b
TG
2471config HAVE_CALL_THUNKS
2472 def_bool y
bea75b33 2473 depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
8f7c0d8b
TG
2474
2475config CALL_THUNKS
2476 def_bool n
931ab636 2477 select CALL_PADDING
8f7c0d8b 2478
b341b20d
PZ
2479config PREFIX_SYMBOLS
2480 def_bool y
931ab636 2481 depends on CALL_PADDING && !CFI_CLANG
b341b20d 2482
f43b9876
PZ
2483menuconfig SPECULATION_MITIGATIONS
2484 bool "Mitigations for speculative execution vulnerabilities"
2485 default y
2486 help
2487 Say Y here to enable options which enable mitigations for
2488 speculative execution hardware vulnerabilities.
2489
2490 If you say N, all mitigations will be disabled. You really
2491 should know what you are doing to say so.
2492
2493if SPECULATION_MITIGATIONS
2494
2495config PAGE_TABLE_ISOLATION
2496 bool "Remove the kernel mapping in user mode"
2497 default y
2498 depends on (X86_64 || X86_PAE)
2499 help
2500 This feature reduces the number of hardware side channels by
2501 ensuring that the majority of kernel addresses are not mapped
2502 into userspace.
2503
ff61f079 2504 See Documentation/arch/x86/pti.rst for more details.
f43b9876
PZ
2505
2506config RETPOLINE
2507 bool "Avoid speculative indirect branches in kernel"
2508 select OBJTOOL if HAVE_OBJTOOL
2509 default y
2510 help
2511 Compile kernel with the retpoline compiler options to guard against
2512 kernel-to-user data leaks by avoiding speculative indirect
2513 branches. Requires a compiler with -mindirect-branch=thunk-extern
2514 support for full protection. The kernel may run slower.
2515
2516config RETHUNK
2517 bool "Enable return-thunks"
2518 depends on RETPOLINE && CC_HAS_RETURN_THUNK
2519 select OBJTOOL if HAVE_OBJTOOL
b648ab48 2520 default y if X86_64
f43b9876
PZ
2521 help
2522 Compile the kernel with the return-thunks compiler option to guard
2523 against kernel-to-user data leaks by avoiding return speculation.
2524 Requires a compiler with -mfunction-return=thunk-extern
2525 support for full protection. The kernel may run slower.
2526
2527config CPU_UNRET_ENTRY
2528 bool "Enable UNRET on kernel entry"
b648ab48 2529 depends on CPU_SUP_AMD && RETHUNK && X86_64
f43b9876
PZ
2530 default y
2531 help
2532 Compile the kernel with support for the retbleed=unret mitigation.
2533
80e4c1cd
TG
2534config CALL_DEPTH_TRACKING
2535 bool "Mitigate RSB underflow with call depth tracking"
2536 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2537 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2538 select CALL_THUNKS
2539 default y
2540 help
2541 Compile the kernel with call depth tracking to mitigate the Intel
2542 SKL Return-Speculation-Buffer (RSB) underflow issue. The
2543 mitigation is off by default and needs to be enabled on the
2544 kernel command line via the retbleed=stuff option. For
2545 non-affected systems the overhead of this option is marginal as
2546 the call depth tracking is using run-time generated call thunks
2547 in a compiler generated padding area and call patching. This
2548 increases text size by ~5%. For non affected systems this space
2549 is unused. On affected SKL systems this results in a significant
2550 performance gain over the IBRS mitigation.
2551
e81dc127
TG
2552config CALL_THUNKS_DEBUG
2553 bool "Enable call thunks and call depth tracking debugging"
2554 depends on CALL_DEPTH_TRACKING
2555 select FUNCTION_ALIGNMENT_32B
2556 default n
2557 help
2558 Enable call/ret counters for imbalance detection and build in
2559 a noisy dmesg about callthunks generation and call patching for
2560 trouble shooting. The debug prints need to be enabled on the
2561 kernel command line with 'debug-callthunks'.
54628de6
RD
2562 Only enable this when you are debugging call thunks as this
2563 creates a noticeable runtime overhead. If unsure say N.
80e4c1cd 2564
f43b9876
PZ
2565config CPU_IBPB_ENTRY
2566 bool "Enable IBPB on kernel entry"
b648ab48 2567 depends on CPU_SUP_AMD && X86_64
f43b9876
PZ
2568 default y
2569 help
2570 Compile the kernel with support for the retbleed=ibpb mitigation.
2571
2572config CPU_IBRS_ENTRY
2573 bool "Enable IBRS on kernel entry"
b648ab48 2574 depends on CPU_SUP_INTEL && X86_64
f43b9876
PZ
2575 default y
2576 help
2577 Compile the kernel with support for the spectre_v2=ibrs mitigation.
2578 This mitigates both spectre_v2 and retbleed at great cost to
2579 performance.
2580
fb3bd914
BPA
2581config CPU_SRSO
2582 bool "Mitigate speculative RAS overflow on AMD"
2583 depends on CPU_SUP_AMD && X86_64 && RETHUNK
2584 default y
2585 help
2586 Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2587
f43b9876
PZ
2588config SLS
2589 bool "Mitigate Straight-Line-Speculation"
2590 depends on CC_HAS_SLS && X86_64
2591 select OBJTOOL if HAVE_OBJTOOL
2592 default n
2593 help
2594 Compile the kernel with straight-line-speculation options to guard
2595 against straight line speculation. The kernel image might be slightly
2596 larger.
2597
53cf5797
DS
2598config GDS_FORCE_MITIGATION
2599 bool "Force GDS Mitigation"
2600 depends on CPU_SUP_INTEL
2601 default n
2602 help
2603 Gather Data Sampling (GDS) is a hardware vulnerability which allows
2604 unprivileged speculative access to data which was previously stored in
2605 vector registers.
2606
2607 This option is equivalent to setting gather_data_sampling=force on the
2608 command line. The microcode mitigation is used if present, otherwise
2609 AVX is disabled as a mitigation. On affected systems that are missing
2610 the microcode any userspace code that unconditionally uses AVX will
2611 break with this option set.
2612
2613 Setting this option on systems not vulnerable to GDS has no effect.
2614
2615 If in doubt, say N.
2616
f43b9876
PZ
2617endif
2618
3072e413
MH
2619config ARCH_HAS_ADD_PAGES
2620 def_bool y
5c11f00b 2621 depends on ARCH_ENABLE_MEMORY_HOTPLUG
3072e413 2622
da85f865 2623menu "Power management and ACPI options"
e279b6c1
SR
2624
2625config ARCH_HIBERNATION_HEADER
3c2362e6 2626 def_bool y
44556530 2627 depends on HIBERNATION
e279b6c1
SR
2628
2629source "kernel/power/Kconfig"
2630
2631source "drivers/acpi/Kconfig"
2632
a6b68076 2633config X86_APM_BOOT
6fc108a0 2634 def_bool y
282e5aab 2635 depends on APM
a6b68076 2636
e279b6c1
SR
2637menuconfig APM
2638 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2639 depends on X86_32 && PM_SLEEP
a7f7f624 2640 help
e279b6c1
SR
2641 APM is a BIOS specification for saving power using several different
2642 techniques. This is mostly useful for battery powered laptops with
2643 APM compliant BIOSes. If you say Y here, the system time will be
2644 reset after a RESUME operation, the /proc/apm device will provide
2645 battery status information, and user-space programs will receive
2646 notification of APM "events" (e.g. battery status change).
2647
2648 If you select "Y" here, you can disable actual use of the APM
2649 BIOS by passing the "apm=off" option to the kernel at boot time.
2650
2651 Note that the APM support is almost completely disabled for
2652 machines with more than one CPU.
2653
2654 In order to use APM, you will need supporting software. For location
151f4e2b 2655 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2656 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2657 <http://www.tldp.org/docs.html#howto>.
2658
2659 This driver does not spin down disk drives (see the hdparm(8)
2660 manpage ("man 8 hdparm") for that), and it doesn't turn off
2661 VESA-compliant "green" monitors.
2662
2663 This driver does not support the TI 4000M TravelMate and the ACER
2664 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2665 desktop machines also don't have compliant BIOSes, and this driver
2666 may cause those machines to panic during the boot phase.
2667
2668 Generally, if you don't have a battery in your machine, there isn't
2669 much point in using this driver and you should say N. If you get
2670 random kernel OOPSes or reboots that don't seem to be related to
2671 anything, try disabling/enabling this option (or disabling/enabling
2672 APM in your BIOS).
2673
2674 Some other things you should try when experiencing seemingly random,
2675 "weird" problems:
2676
2677 1) make sure that you have enough swap space and that it is
2678 enabled.
7987448f 2679 2) pass the "idle=poll" option to the kernel
e279b6c1
SR
2680 3) switch on floating point emulation in the kernel and pass
2681 the "no387" option to the kernel
2682 4) pass the "floppy=nodma" option to the kernel
2683 5) pass the "mem=4M" option to the kernel (thereby disabling
2684 all but the first 4 MB of RAM)
2685 6) make sure that the CPU is not over clocked.
2686 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2687 8) disable the cache from your BIOS settings
2688 9) install a fan for the video card or exchange video RAM
2689 10) install a better fan for the CPU
2690 11) exchange RAM chips
2691 12) exchange the motherboard.
2692
2693 To compile this driver as a module, choose M here: the
2694 module will be called apm.
2695
2696if APM
2697
2698config APM_IGNORE_USER_SUSPEND
2699 bool "Ignore USER SUSPEND"
a7f7f624 2700 help
e279b6c1
SR
2701 This option will ignore USER SUSPEND requests. On machines with a
2702 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2703 series notebooks, it is necessary to say Y because of a BIOS bug.
2704
2705config APM_DO_ENABLE
2706 bool "Enable PM at boot time"
a7f7f624 2707 help
e279b6c1
SR
2708 Enable APM features at boot time. From page 36 of the APM BIOS
2709 specification: "When disabled, the APM BIOS does not automatically
2710 power manage devices, enter the Standby State, enter the Suspend
2711 State, or take power saving steps in response to CPU Idle calls."
2712 This driver will make CPU Idle calls when Linux is idle (unless this
2713 feature is turned off -- see "Do CPU IDLE calls", below). This
2714 should always save battery power, but more complicated APM features
2715 will be dependent on your BIOS implementation. You may need to turn
2716 this option off if your computer hangs at boot time when using APM
2717 support, or if it beeps continuously instead of suspending. Turn
2718 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2719 T400CDT. This is off by default since most machines do fine without
2720 this feature.
2721
2722config APM_CPU_IDLE
dd8af076 2723 depends on CPU_IDLE
e279b6c1 2724 bool "Make CPU Idle calls when idle"
a7f7f624 2725 help
e279b6c1
SR
2726 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2727 On some machines, this can activate improved power savings, such as
2728 a slowed CPU clock rate, when the machine is idle. These idle calls
2729 are made after the idle loop has run for some length of time (e.g.,
2730 333 mS). On some machines, this will cause a hang at boot time or
2731 whenever the CPU becomes idle. (On machines with more than one CPU,
2732 this option does nothing.)
2733
2734config APM_DISPLAY_BLANK
2735 bool "Enable console blanking using APM"
a7f7f624 2736 help
e279b6c1
SR
2737 Enable console blanking using the APM. Some laptops can use this to
2738 turn off the LCD backlight when the screen blanker of the Linux
2739 virtual console blanks the screen. Note that this is only used by
2740 the virtual console screen blanker, and won't turn off the backlight
2741 when using the X Window system. This also doesn't have anything to
2742 do with your VESA-compliant power-saving monitor. Further, this
2743 option doesn't work for all laptops -- it might not turn off your
2744 backlight at all, or it might print a lot of errors to the console,
2745 especially if you are using gpm.
2746
2747config APM_ALLOW_INTS
2748 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2749 help
e279b6c1
SR
2750 Normally we disable external interrupts while we are making calls to
2751 the APM BIOS as a measure to lessen the effects of a badly behaving
2752 BIOS implementation. The BIOS should reenable interrupts if it
2753 needs to. Unfortunately, some BIOSes do not -- especially those in
2754 many of the newer IBM Thinkpads. If you experience hangs when you
2755 suspend, try setting this to Y. Otherwise, say N.
2756
e279b6c1
SR
2757endif # APM
2758
bb0a56ec 2759source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2760
2761source "drivers/cpuidle/Kconfig"
2762
27471fdb
AH
2763source "drivers/idle/Kconfig"
2764
e279b6c1
SR
2765endmenu
2766
e279b6c1
SR
2767menu "Bus options (PCI etc.)"
2768
e279b6c1
SR
2769choice
2770 prompt "PCI access mode"
efefa6f6 2771 depends on X86_32 && PCI
e279b6c1 2772 default PCI_GOANY
a7f7f624 2773 help
e279b6c1
SR
2774 On PCI systems, the BIOS can be used to detect the PCI devices and
2775 determine their configuration. However, some old PCI motherboards
2776 have BIOS bugs and may crash if this is done. Also, some embedded
2777 PCI-based systems don't have any BIOS at all. Linux can also try to
2778 detect the PCI hardware directly without using the BIOS.
2779
2780 With this option, you can specify how Linux should detect the
2781 PCI devices. If you choose "BIOS", the BIOS will be used,
2782 if you choose "Direct", the BIOS won't be used, and if you
2783 choose "MMConfig", then PCI Express MMCONFIG will be used.
2784 If you choose "Any", the kernel will try MMCONFIG, then the
2785 direct access method and falls back to the BIOS if that doesn't
2786 work. If unsure, go with the default, which is "Any".
2787
2788config PCI_GOBIOS
2789 bool "BIOS"
2790
2791config PCI_GOMMCONFIG
2792 bool "MMConfig"
2793
2794config PCI_GODIRECT
2795 bool "Direct"
2796
3ef0e1f8 2797config PCI_GOOLPC
76fb6570 2798 bool "OLPC XO-1"
3ef0e1f8
AS
2799 depends on OLPC
2800
2bdd1b03
AS
2801config PCI_GOANY
2802 bool "Any"
2803
e279b6c1
SR
2804endchoice
2805
2806config PCI_BIOS
3c2362e6 2807 def_bool y
efefa6f6 2808 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2809
2810# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2811config PCI_DIRECT
3c2362e6 2812 def_bool y
0aba496f 2813 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2814
2815config PCI_MMCONFIG
b45c9f36
JK
2816 bool "Support mmconfig PCI config space access" if X86_64
2817 default y
4590d98f 2818 depends on PCI && (ACPI || JAILHOUSE_GUEST)
b45c9f36 2819 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2820
3ef0e1f8 2821config PCI_OLPC
2bdd1b03
AS
2822 def_bool y
2823 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2824
b5401a96
AN
2825config PCI_XEN
2826 def_bool y
2827 depends on PCI && XEN
b5401a96 2828
8364e1f8
JK
2829config MMCONF_FAM10H
2830 def_bool y
2831 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2832
3f6ea84a 2833config PCI_CNB20LE_QUIRK
6a108a14 2834 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2835 depends on PCI
3f6ea84a
IS
2836 help
2837 Read the PCI windows out of the CNB20LE host bridge. This allows
2838 PCI hotplug to work on systems with the CNB20LE chipset which do
2839 not have ACPI.
2840
64a5fed6
BH
2841 There's no public spec for this chipset, and this functionality
2842 is known to be incomplete.
2843
2844 You should say N unless you know you need this.
2845
3a495511 2846config ISA_BUS
17a2a129 2847 bool "ISA bus support on modern systems" if EXPERT
3a495511 2848 help
17a2a129
WBG
2849 Expose ISA bus device drivers and options available for selection and
2850 configuration. Enable this option if your target machine has an ISA
2851 bus. ISA is an older system, displaced by PCI and newer bus
2852 architectures -- if your target machine is modern, it probably does
2853 not have an ISA bus.
3a495511
WBG
2854
2855 If unsure, say N.
2856
1c00f016 2857# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2858config ISA_DMA_API
1c00f016
DR
2859 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2860 default y
2861 help
2862 Enables ISA-style DMA support for devices requiring such controllers.
2863 If unsure, say Y.
e279b6c1 2864
51e68d05
LT
2865if X86_32
2866
e279b6c1
SR
2867config ISA
2868 bool "ISA support"
a7f7f624 2869 help
e279b6c1
SR
2870 Find out whether you have ISA slots on your motherboard. ISA is the
2871 name of a bus system, i.e. the way the CPU talks to the other stuff
2872 inside your box. Other bus systems are PCI, EISA, MicroChannel
2873 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2874 newer boards don't support it. If you have ISA, say Y, otherwise N.
2875
e279b6c1
SR
2876config SCx200
2877 tristate "NatSemi SCx200 support"
a7f7f624 2878 help
e279b6c1
SR
2879 This provides basic support for National Semiconductor's
2880 (now AMD's) Geode processors. The driver probes for the
2881 PCI-IDs of several on-chip devices, so its a good dependency
2882 for other scx200_* drivers.
2883
2884 If compiled as a module, the driver is named scx200.
2885
2886config SCx200HR_TIMER
2887 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2888 depends on SCx200
e279b6c1 2889 default y
a7f7f624 2890 help
e279b6c1
SR
2891 This driver provides a clocksource built upon the on-chip
2892 27MHz high-resolution timer. Its also a workaround for
2893 NSC Geode SC-1100's buggy TSC, which loses time when the
2894 processor goes idle (as is done by the scheduler). The
2895 other workaround is idle=poll boot option.
2896
3ef0e1f8
AS
2897config OLPC
2898 bool "One Laptop Per Child support"
54008979 2899 depends on !X86_PAE
3c554946 2900 select GPIOLIB
dc3119e7 2901 select OF
45bb1674 2902 select OF_PROMTREE
b4e51854 2903 select IRQ_DOMAIN
0c3d931b 2904 select OLPC_EC
a7f7f624 2905 help
3ef0e1f8
AS
2906 Add support for detecting the unique features of the OLPC
2907 XO hardware.
2908
a3128588
DD
2909config OLPC_XO1_PM
2910 bool "OLPC XO-1 Power Management"
fa112cf1 2911 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 2912 help
97c4cb71 2913 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2914
cfee9597
DD
2915config OLPC_XO1_RTC
2916 bool "OLPC XO-1 Real Time Clock"
2917 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 2918 help
cfee9597
DD
2919 Add support for the XO-1 real time clock, which can be used as a
2920 programmable wakeup source.
2921
7feda8e9
DD
2922config OLPC_XO1_SCI
2923 bool "OLPC XO-1 SCI extras"
92e830f2 2924 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2925 depends on INPUT=y
d8d01a63 2926 select POWER_SUPPLY
a7f7f624 2927 help
7feda8e9 2928 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2929 - EC-driven system wakeups
7feda8e9 2930 - Power button
7bc74b3d 2931 - Ebook switch
2cf2baea 2932 - Lid switch
e1040ac6
DD
2933 - AC adapter status updates
2934 - Battery status updates
7feda8e9 2935
a0f30f59
DD
2936config OLPC_XO15_SCI
2937 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2938 depends on OLPC && ACPI
2939 select POWER_SUPPLY
a7f7f624 2940 help
a0f30f59
DD
2941 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2942 - EC-driven system wakeups
2943 - AC adapter status updates
2944 - Battery status updates
bf1ebf00 2945
d4f3e350
EW
2946config ALIX
2947 bool "PCEngines ALIX System Support (LED setup)"
2948 select GPIOLIB
a7f7f624 2949 help
d4f3e350
EW
2950 This option enables system support for the PCEngines ALIX.
2951 At present this just sets up LEDs for GPIO control on
2952 ALIX2/3/6 boards. However, other system specific setup should
2953 get added here.
2954
2955 Note: You must still enable the drivers for GPIO and LED support
2956 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2957
2958 Note: You have to set alix.force=1 for boards with Award BIOS.
2959
da4e3302
PP
2960config NET5501
2961 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2962 select GPIOLIB
a7f7f624 2963 help
da4e3302
PP
2964 This option enables system support for the Soekris Engineering net5501.
2965
3197059a
PP
2966config GEOS
2967 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2968 select GPIOLIB
2969 depends on DMI
a7f7f624 2970 help
3197059a
PP
2971 This option enables system support for the Traverse Technologies GEOS.
2972
7d029125
VD
2973config TS5500
2974 bool "Technologic Systems TS-5500 platform support"
2975 depends on MELAN
2976 select CHECK_SIGNATURE
2977 select NEW_LEDS
2978 select LEDS_CLASS
a7f7f624 2979 help
7d029125
VD
2980 This option enables system support for the Technologic Systems TS-5500.
2981
bc0120fd
SR
2982endif # X86_32
2983
23ac4ae8 2984config AMD_NB
e279b6c1 2985 def_bool y
0e152cd7 2986 depends on CPU_SUP_AMD && PCI
e279b6c1 2987
e279b6c1
SR
2988endmenu
2989
1572497c 2990menu "Binary Emulations"
e279b6c1
SR
2991
2992config IA32_EMULATION
2993 bool "IA32 Emulation"
2994 depends on X86_64
39f88911 2995 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2996 select BINFMT_ELF
39f88911 2997 select COMPAT_OLD_SIGACTION
a7f7f624 2998 help
5fd92e65
L
2999 Include code to run legacy 32-bit programs under a
3000 64-bit kernel. You should likely turn this on, unless you're
3001 100% sure that you don't have any 32-bit programs left.
e279b6c1 3002
a11e0975
NB
3003config IA32_EMULATION_DEFAULT_DISABLED
3004 bool "IA32 emulation disabled by default"
3005 default n
3006 depends on IA32_EMULATION
3007 help
3008 Make IA32 emulation disabled by default. This prevents loading 32-bit
3009 processes and access to 32-bit syscalls. If unsure, leave it to its
3010 default value.
3011
83a44a4f 3012config X86_X32_ABI
6ea30386 3013 bool "x32 ABI for 64-bit mode"
9b54050b 3014 depends on X86_64
aaeed6ec
NC
3015 # llvm-objcopy does not convert x86_64 .note.gnu.property or
3016 # compressed debug sections to x86_x32 properly:
3017 # https://github.com/ClangBuiltLinux/linux/issues/514
3018 # https://github.com/ClangBuiltLinux/linux/issues/1141
3019 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
a7f7f624 3020 help
5fd92e65
L
3021 Include code to run binaries for the x32 native 32-bit ABI
3022 for 64-bit processors. An x32 process gets access to the
3023 full 64-bit register file and wide data path while leaving
3024 pointers at 32 bits for smaller memory footprint.
3025
953fee1d
IM
3026config COMPAT_32
3027 def_bool y
3028 depends on IA32_EMULATION || X86_32
3029 select HAVE_UID16
3030 select OLD_SIGSUSPEND3
3031
e279b6c1 3032config COMPAT
3c2362e6 3033 def_bool y
83a44a4f 3034 depends on IA32_EMULATION || X86_X32_ABI
e279b6c1
SR
3035
3036config COMPAT_FOR_U64_ALIGNMENT
3120e25e 3037 def_bool y
a9251280 3038 depends on COMPAT
ee009e4a 3039
e279b6c1
SR
3040endmenu
3041
e5beae16
KP
3042config HAVE_ATOMIC_IOMAP
3043 def_bool y
3044 depends on X86_32
3045
edf88417 3046source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
3047
3048source "arch/x86/Kconfig.assembler"