sh/kexec: refactor for kernel/Kconfig.kexec
[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
3120e25e
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 ARCH_USE_CMPXCHG_LOCKREF
32 select HAVE_ARCH_SOFT_DIRTY
33 select MODULES_USE_ELF_RELA
f616ab59 34 select NEED_DMA_MAP_STATE
09230cbc 35 select SWIOTLB
7facdc42 36 select ARCH_HAS_ELFCORE_COMPAT
63703f37 37 select ZONE_DMA32
1032c0ba 38
518049d9
SRV
39config FORCE_DYNAMIC_FTRACE
40 def_bool y
41 depends on X86_32
42 depends on FUNCTION_TRACER
43 select DYNAMIC_FTRACE
44 help
758cd94a
JH
45 We keep the static function tracing (!DYNAMIC_FTRACE) around
46 in order to test the non static function tracing in the
47 generic code, as other architectures still use it. But we
48 only need to keep it around for x86_64. No need to keep it
49 for x86_32. For x86_32, force DYNAMIC_FTRACE.
d94e0685
IM
50#
51# Arch settings
52#
53# ( Note that options that are marked 'if X86_64' could in principle be
54# ported to 32-bit as well. )
55#
8d5fffb9 56config X86
3c2362e6 57 def_bool y
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IM
58 #
59 # Note: keep this list sorted alphabetically
60 #
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IM
61 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
62 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
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
2792d84e 75 select ARCH_HAS_CURRENT_STACK_POINTER
fa5b6ec9 76 select ARCH_HAS_DEBUG_VIRTUAL
399145f9 77 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
21266be9 78 select ARCH_HAS_DEVMEM_IS_ALLOWED
b1a57bbf 79 select ARCH_HAS_EARLY_DEBUG if KGDB
6471b825 80 select ARCH_HAS_ELF_RANDOMIZE
72d93104 81 select ARCH_HAS_FAST_MULTIPLIER
6974f0c4 82 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 83 select ARCH_HAS_GCOV_PROFILE_ALL
bece04b5 84 select ARCH_HAS_KCOV if X86_64
0c9c1d56 85 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 86 select ARCH_HAS_MEMBARRIER_SYNC_CORE
49f88c70 87 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
0ebeea8c 88 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
c763ea26 89 select ARCH_HAS_PMEM_API if X86_64
17596731 90 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 91 select ARCH_HAS_PTE_SPECIAL
eed9a328 92 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2
0aed55af 93 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
ec6347bb 94 select ARCH_HAS_COPY_MC if X86_64
d2852a22 95 select ARCH_HAS_SET_MEMORY
d253ca0c 96 select ARCH_HAS_SET_DIRECT_MAP
ad21fc4f
LA
97 select ARCH_HAS_STRICT_KERNEL_RWX
98 select ARCH_HAS_STRICT_MODULE_RWX
ac1ab12a 99 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
25c619e5 100 select ARCH_HAS_SYSCALL_WRAPPER
c6d30853 101 select ARCH_HAS_UBSAN_SANITIZE_ALL
7e01ccb4 102 select ARCH_HAS_DEBUG_WX
63703f37 103 select ARCH_HAS_ZONE_DMA_SET if EXPERT
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IM
104 select ARCH_HAVE_NMI_SAFE_CMPXCHG
105 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 106 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 107 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 108 select ARCH_STACKWALK
2c870e61 109 select ARCH_SUPPORTS_ACPI
6471b825 110 select ARCH_SUPPORTS_ATOMIC_RMW
5d6ad668 111 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
d283d422 112 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64
6471b825 113 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
14df3267 114 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096
3c516f89
ST
115 select ARCH_SUPPORTS_CFI_CLANG if X86_64
116 select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG
583bfd48
NC
117 select ARCH_SUPPORTS_LTO_CLANG
118 select ARCH_SUPPORTS_LTO_CLANG_THIN
6471b825 119 select ARCH_USE_BUILTIN_BSWAP
dce44566 120 select ARCH_USE_MEMTEST
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IM
121 select ARCH_USE_QUEUED_RWLOCKS
122 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 123 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 124 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 125 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 126 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
51c2ee6d 127 select ARCH_WANTS_NO_INSTR
07431506 128 select ARCH_WANT_GENERAL_HUGETLB
3876d4a3 129 select ARCH_WANT_HUGE_PMD_SHARE
59612b24 130 select ARCH_WANT_LD_ORPHAN_WARN
0b376f1e 131 select ARCH_WANT_OPTIMIZE_VMEMMAP if X86_64
38d8b4e6 132 select ARCH_WANTS_THP_SWAP if X86_64
b5f06f64 133 select ARCH_HAS_PARANOID_L1D_FLUSH
10916706 134 select BUILDTIME_TABLE_SORT
6471b825 135 select CLKEVT_I8253
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IM
136 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
137 select CLOCKSOURCE_WATCHDOG
7cf8f44a
AP
138 # Word-size accesses may read uninitialized data past the trailing \0
139 # in strings and cause false KMSAN reports.
140 select DCACHE_WORD_ACCESS if !KMSAN
3aac3ebe 141 select DYNAMIC_SIGFRAME
45471cd9
LT
142 select EDAC_ATOMIC_SCRUB
143 select EDAC_SUPPORT
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IM
144 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
145 select GENERIC_CLOCKEVENTS_MIN_ADJUST
146 select GENERIC_CMOS_UPDATE
147 select GENERIC_CPU_AUTOPROBE
61dc0f55 148 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 149 select GENERIC_EARLY_IOREMAP
27d6b4d1 150 select GENERIC_ENTRY
6471b825 151 select GENERIC_IOMAP
c7d6c9dd 152 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 153 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 154 select GENERIC_IRQ_MIGRATION if SMP
6471b825 155 select GENERIC_IRQ_PROBE
c201c917 156 select GENERIC_IRQ_RESERVATION_MODE
6471b825
IM
157 select GENERIC_IRQ_SHOW
158 select GENERIC_PENDING_IRQ if SMP
2ae27137 159 select GENERIC_PTDUMP
6471b825 160 select GENERIC_SMP_IDLE_THREAD
6471b825 161 select GENERIC_TIME_VSYSCALL
7ac87074 162 select GENERIC_GETTIMEOFDAY
550a77a7 163 select GENERIC_VDSO_TIME_NS
6ca297d4 164 select GUP_GET_PXX_LOW_HIGH if X86_PAE
17e5888e 165 select HARDIRQS_SW_RESEND
7edaeb68 166 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
fcbfe812 167 select HAS_IOPORT
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IM
168 select HAVE_ACPI_APEI if ACPI
169 select HAVE_ACPI_APEI_NMI if ACPI
170 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
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IM
171 select HAVE_ARCH_AUDITSYSCALL
172 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
eed1fcee 173 select HAVE_ARCH_HUGE_VMALLOC if X86_64
6471b825 174 select HAVE_ARCH_JUMP_LABEL
b34006c4 175 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 176 select HAVE_ARCH_KASAN if X86_64
0609ae01 177 select HAVE_ARCH_KASAN_VMALLOC if X86_64
1dc0da6e 178 select HAVE_ARCH_KFENCE
4ca8cc8d 179 select HAVE_ARCH_KMSAN if X86_64
6471b825 180 select HAVE_ARCH_KGDB
9e08f57d
DC
181 select HAVE_ARCH_MMAP_RND_BITS if MMU
182 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 183 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 184 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 185 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 186 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 187 select HAVE_ARCH_STACKLEAK
6471b825
IM
188 select HAVE_ARCH_TRACEHOOK
189 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 190 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 191 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
7677f7fd 192 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD
e37e43a4 193 select HAVE_ARCH_VMAP_STACK if X86_64
fe950f60 194 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
c763ea26 195 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 196 select HAVE_ASM_MODVERSIONS
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IM
197 select HAVE_CMPXCHG_DOUBLE
198 select HAVE_CMPXCHG_LOCAL
24a9c541
FW
199 select HAVE_CONTEXT_TRACKING_USER if X86_64
200 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER
cf4db259 201 select HAVE_C_RECORDMCOUNT
03f16cd0 202 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL
280981d6 203 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT
4ed308c4 204 select HAVE_BUILDTIME_MCOUNT_SORT
6471b825 205 select HAVE_DEBUG_KMEMLEAK
6471b825 206 select HAVE_DMA_CONTIGUOUS
677aa9f7 207 select HAVE_DYNAMIC_FTRACE
06aeaaea 208 select HAVE_DYNAMIC_FTRACE_WITH_REGS
02a474ca 209 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64
562955fe 210 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
c316eb44 211 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64
503e4510 212 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64
03f5781b 213 select HAVE_EBPF_JIT
58340a07 214 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 215 select HAVE_EISA
5f56a5df 216 select HAVE_EXIT_THREAD
67a929e0 217 select HAVE_FAST_GUP
644e0e8d 218 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 219 select HAVE_FTRACE_MCOUNT_RECORD
d938ba17 220 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
4a30e4c9 221 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE)
6471b825 222 select HAVE_FUNCTION_TRACER
6b90bd4b 223 select HAVE_GCC_PLUGINS
6471b825 224 select HAVE_HW_BREAKPOINT
6471b825 225 select HAVE_IOREMAP_PROT
624db9ea 226 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
6471b825 227 select HAVE_IRQ_TIME_ACCOUNTING
4ab7674f 228 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL
2e9f3bdd 229 select HAVE_KERNEL_BZIP2
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IM
230 select HAVE_KERNEL_GZIP
231 select HAVE_KERNEL_LZ4
2e9f3bdd 232 select HAVE_KERNEL_LZMA
13510997 233 select HAVE_KERNEL_LZO
6471b825 234 select HAVE_KERNEL_XZ
fb46d057 235 select HAVE_KERNEL_ZSTD
6471b825
IM
236 select HAVE_KPROBES
237 select HAVE_KPROBES_ON_FTRACE
540adea3 238 select HAVE_FUNCTION_ERROR_INJECTION
6471b825 239 select HAVE_KRETPROBES
f3a112c0 240 select HAVE_RETHOOK
6471b825
IM
241 select HAVE_KVM
242 select HAVE_LIVEPATCH if X86_64
0102752e 243 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 244 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 245 select HAVE_MOVE_PMD
be37c98d 246 select HAVE_MOVE_PUD
22102f45 247 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL
42a0bb3f 248 select HAVE_NMI
489e355b 249 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL
03f16cd0 250 select HAVE_OBJTOOL if X86_64
6471b825
IM
251 select HAVE_OPTPROBES
252 select HAVE_PCSPKR_PLATFORM
253 select HAVE_PERF_EVENTS
c01d4323 254 select HAVE_PERF_EVENTS_NMI
92e5aae4 255 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 256 select HAVE_PCI
c5e63197 257 select HAVE_PERF_REGS
c5ebcedb 258 select HAVE_PERF_USER_STACK_DUMP
03f16cd0 259 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
1e9fdf21 260 select MMU_GATHER_MERGE_VMAS
00998085 261 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 262 select HAVE_REGS_AND_STACK_ACCESS_API
03f16cd0 263 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION
3c88ee19 264 select HAVE_FUNCTION_ARG_ACCESS_API
7ecd19cf 265 select HAVE_SETUP_PER_CPU_AREA
cd1a41ce 266 select HAVE_SOFTIRQ_ON_OWN_STACK
d148eac0 267 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
03f16cd0 268 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL
e6d6c071 269 select HAVE_STATIC_CALL
03f16cd0 270 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL
99cf983c 271 select HAVE_PREEMPT_DYNAMIC_CALL
d6761b8f 272 select HAVE_RSEQ
09498135 273 select HAVE_RUST if X86_64
6471b825 274 select HAVE_SYSCALL_TRACEPOINTS
5f3da8c0 275 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL
6471b825 276 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 277 select HAVE_USER_RETURN_NOTIFIER
7ac87074 278 select HAVE_GENERIC_VDSO
0c7ffa32 279 select HOTPLUG_PARALLEL if SMP && X86_64
05736e4a 280 select HOTPLUG_SMT if SMP
0c7ffa32 281 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32
c0185808 282 select IRQ_FORCED_THREADING
c2508ec5 283 select LOCK_MM_AND_FIND_VMA
7ecd19cf
KW
284 select NEED_PER_CPU_EMBED_FIRST_CHUNK
285 select NEED_PER_CPU_PAGE_FIRST_CHUNK
86596f0a 286 select NEED_SG_DMA_LENGTH
2eac9c2d 287 select PCI_DOMAINS if PCI
625210cf 288 select PCI_LOCKLESS_CONFIG if PCI
6471b825 289 select PERF_EVENTS
3195ef59 290 select RTC_LIB
d6faca40 291 select RTC_MC146818_LIB
6471b825 292 select SPARSE_IRQ
6471b825 293 select SYSCTL_EXCEPTION_TRACE
15f4eae7 294 select THREAD_INFO_IN_TASK
4aae683f 295 select TRACE_IRQFLAGS_SUPPORT
4510bffb 296 select TRACE_IRQFLAGS_NMI_SUPPORT
6471b825 297 select USER_STACKTRACE_SUPPORT
3b02a051 298 select HAVE_ARCH_KCSAN if X86_64
0c608dad 299 select PROC_PID_ARCH_STATUS if PROC_FS
50468e43 300 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX
d49a0626
PZ
301 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16
302 select FUNCTION_ALIGNMENT_4B
9e2b4be3 303 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
ceea991a 304 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
7d8330a5 305
ba7e4d13 306config INSTRUCTION_DECODER
3120e25e
JB
307 def_bool y
308 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 309
51b26ada
LT
310config OUTPUT_FORMAT
311 string
312 default "elf32-i386" if X86_32
313 default "elf64-x86-64" if X86_64
314
8d5fffb9 315config LOCKDEP_SUPPORT
3c2362e6 316 def_bool y
8d5fffb9
SR
317
318config STACKTRACE_SUPPORT
3c2362e6 319 def_bool y
8d5fffb9 320
8d5fffb9 321config MMU
3c2362e6 322 def_bool y
8d5fffb9 323
9e08f57d
DC
324config ARCH_MMAP_RND_BITS_MIN
325 default 28 if 64BIT
326 default 8
327
328config ARCH_MMAP_RND_BITS_MAX
329 default 32 if 64BIT
330 default 16
331
332config ARCH_MMAP_RND_COMPAT_BITS_MIN
333 default 8
334
335config ARCH_MMAP_RND_COMPAT_BITS_MAX
336 default 16
337
8d5fffb9
SR
338config SBUS
339 bool
340
341config GENERIC_ISA_DMA
3120e25e
JB
342 def_bool y
343 depends on ISA_DMA_API
8d5fffb9 344
d911c67e
AP
345config GENERIC_CSUM
346 bool
347 default y if KMSAN || KASAN
348
8d5fffb9 349config GENERIC_BUG
3c2362e6 350 def_bool y
8d5fffb9 351 depends on BUG
b93a531e
JB
352 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
353
354config GENERIC_BUG_RELATIVE_POINTERS
355 bool
8d5fffb9 356
8d5fffb9 357config ARCH_MAY_HAVE_PC_FDC
3120e25e
JB
358 def_bool y
359 depends on ISA_DMA_API
8d5fffb9 360
1032c0ba
SR
361config GENERIC_CALIBRATE_DELAY
362 def_bool y
363
9a0b8415 364config ARCH_HAS_CPU_RELAX
365 def_bool y
366
801e4062
JB
367config ARCH_HIBERNATION_POSSIBLE
368 def_bool y
801e4062 369
f4cb5700
JB
370config ARCH_SUSPEND_POSSIBLE
371 def_bool y
f4cb5700 372
8d5fffb9 373config AUDIT_ARCH
e0fd24a3 374 def_bool y if X86_64
8d5fffb9 375
d6f2d75a
AR
376config KASAN_SHADOW_OFFSET
377 hex
378 depends on KASAN
379 default 0xdffffc0000000000
380
69575d38
SW
381config HAVE_INTEL_TXT
382 def_bool y
6ea30386 383 depends on INTEL_IOMMU && ACPI
69575d38 384
6b0c3d44
SR
385config X86_32_SMP
386 def_bool y
387 depends on X86_32 && SMP
388
389config X86_64_SMP
390 def_bool y
391 depends on X86_64 && SMP
392
2b144498
SD
393config ARCH_SUPPORTS_UPROBES
394 def_bool y
395
d20642f0
RH
396config FIX_EARLYCON_MEM
397 def_bool y
398
94d49eb3
KS
399config DYNAMIC_PHYSICAL_MASK
400 bool
401
98233368
KS
402config PGTABLE_LEVELS
403 int
77ef56e4 404 default 5 if X86_5LEVEL
98233368
KS
405 default 4 if X86_64
406 default 3 if X86_PAE
407 default 2
408
2a61f474
MY
409config CC_HAS_SANE_STACKPROTECTOR
410 bool
1b866781
NC
411 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
412 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
2a61f474 413 help
758cd94a
JH
414 We have to make sure stack protector is unconditionally disabled if
415 the compiler produces broken code or if it does not let us control
416 the segment on 32-bit kernels.
2a61f474 417
506f1d07
SR
418menu "Processor type and features"
419
506f1d07
SR
420config SMP
421 bool "Symmetric multi-processing support"
a7f7f624 422 help
506f1d07 423 This enables support for systems with more than one CPU. If you have
4a474157
RG
424 a system with only one CPU, say N. If you have a system with more
425 than one CPU, say Y.
506f1d07 426
4a474157 427 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
428 machines, but will use only one CPU of a multiprocessor machine. If
429 you say Y here, the kernel will run on many, but not all,
4a474157 430 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
431 will run faster if you say N here.
432
433 Note that if you say Y here and choose architecture "586" or
434 "Pentium" under "Processor family", the kernel will not work on 486
435 architectures. Similarly, multiprocessor kernels for the "PPro"
436 architecture may not work on all Pentium based boards.
437
438 People using multiprocessor machines who say Y here should also say
439 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
440 Management" code will be disabled if you say Y here.
441
ff61f079 442 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
4f4cfa6c 443 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
444 <http://www.tldp.org/docs.html#howto>.
445
446 If you don't know what to do here, say N.
447
06cd9a7d
YL
448config X86_X2APIC
449 bool "Support x2apic"
19e3d60d 450 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 451 help
06cd9a7d
YL
452 This enables x2apic support on CPUs that have this feature.
453
454 This allows 32-bit apic IDs (so it can support very large systems),
455 and accesses the local apic via MSRs not via mmio.
456
b8d1d163
DS
457 Some Intel systems circa 2022 and later are locked into x2APIC mode
458 and can not fall back to the legacy APIC modes if SGX or TDX are
e3998434
MJ
459 enabled in the BIOS. They will boot with very reduced functionality
460 without enabling this option.
b8d1d163 461
06cd9a7d
YL
462 If you don't know what to do here, say N.
463
6695c85b 464config X86_MPPARSE
4590d98f 465 bool "Enable MPS table" if ACPI
7a527688 466 default y
5ab74722 467 depends on X86_LOCAL_APIC
a7f7f624 468 help
6695c85b
YL
469 For old smp systems that do not have proper acpi support. Newer systems
470 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 471
ddd70cf9 472config GOLDFISH
b03b016f
KK
473 def_bool y
474 depends on X86_GOLDFISH
ddd70cf9 475
e6d42931
JW
476config X86_CPU_RESCTRL
477 bool "x86 CPU resource control support"
6fe07ce3 478 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 479 select KERNFS
e79f15a4 480 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 481 help
e6d42931 482 Enable x86 CPU resource control support.
6fe07ce3
BM
483
484 Provide support for the allocation and monitoring of system resources
485 usage by the CPU.
486
487 Intel calls this Intel Resource Director Technology
488 (Intel(R) RDT). More information about RDT can be found in the
489 Intel x86 Architecture Software Developer Manual.
490
491 AMD calls this AMD Platform Quality of Service (AMD QoS).
492 More information about AMD QoS can be found in the AMD64 Technology
493 Platform Quality of Service Extensions manual.
78e99b4a
FY
494
495 Say N if unsure.
496
8425091f 497if X86_32
a0d0bb4d
RD
498config X86_BIGSMP
499 bool "Support for big SMP systems with more than 8 CPUs"
500 depends on SMP
a7f7f624 501 help
e133f6ea 502 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 503
c5c606d9
RT
504config X86_EXTENDED_PLATFORM
505 bool "Support for extended (non-PC) x86 platforms"
506 default y
a7f7f624 507 help
06ac8346
IM
508 If you disable this option then the kernel will only support
509 standard PC platforms. (which covers the vast majority of
510 systems out there.)
511
8425091f
RT
512 If you enable this option then you'll be able to select support
513 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 514 Goldfish (Android emulator)
8425091f 515 AMD Elan
8425091f
RT
516 RDC R-321x SoC
517 SGI 320/540 (Visual Workstation)
83125a3a 518 STA2X11-based (e.g. Northville)
3f4110a4 519 Moorestown MID devices
06ac8346
IM
520
521 If you have one of these systems, or if you want to build a
522 generic distribution kernel, say Y here - otherwise say N.
758cd94a 523endif # X86_32
06ac8346 524
8425091f
RT
525if X86_64
526config X86_EXTENDED_PLATFORM
527 bool "Support for extended (non-PC) x86 platforms"
528 default y
a7f7f624 529 help
8425091f
RT
530 If you disable this option then the kernel will only support
531 standard PC platforms. (which covers the vast majority of
532 systems out there.)
533
534 If you enable this option then you'll be able to select support
535 for the following (non-PC) 64 bit x86 platforms:
44b111b5 536 Numascale NumaChip
8425091f
RT
537 ScaleMP vSMP
538 SGI Ultraviolet
539
540 If you have one of these systems, or if you want to build a
541 generic distribution kernel, say Y here - otherwise say N.
758cd94a 542endif # X86_64
c5c606d9
RT
543# This is an alphabetically sorted list of 64 bit extended platforms
544# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
545config X86_NUMACHIP
546 bool "Numascale NumaChip"
547 depends on X86_64
548 depends on X86_EXTENDED_PLATFORM
549 depends on NUMA
550 depends on SMP
551 depends on X86_X2APIC
f9726bfd 552 depends on PCI_MMCONFIG
a7f7f624 553 help
44b111b5
SP
554 Adds support for Numascale NumaChip large-SMP systems. Needed to
555 enable more than ~168 cores.
556 If you don't have one of these, you should say N here.
506f1d07 557
c5c606d9
RT
558config X86_VSMP
559 bool "ScaleMP vSMP"
6276a074 560 select HYPERVISOR_GUEST
c5c606d9
RT
561 select PARAVIRT
562 depends on X86_64 && PCI
563 depends on X86_EXTENDED_PLATFORM
ead91d4b 564 depends on SMP
a7f7f624 565 help
c5c606d9
RT
566 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
567 supposed to run on these EM64T-based machines. Only choose this option
568 if you have one of these machines.
5e3a77e9 569
03b48632
NP
570config X86_UV
571 bool "SGI Ultraviolet"
572 depends on X86_64
c5c606d9 573 depends on X86_EXTENDED_PLATFORM
54c28d29 574 depends on NUMA
1ecb4ae5 575 depends on EFI
c2209ea5 576 depends on KEXEC_CORE
9d6c26e7 577 depends on X86_X2APIC
1222e564 578 depends on PCI
a7f7f624 579 help
03b48632
NP
580 This option is needed in order to support SGI Ultraviolet systems.
581 If you don't have one of these, you should say N here.
582
c5c606d9
RT
583# Following is an alphabetically sorted list of 32 bit extended platforms
584# Please maintain the alphabetic order if and when there are additions
506f1d07 585
ddd70cf9 586config X86_GOLDFISH
b03b016f
KK
587 bool "Goldfish (Virtual Platform)"
588 depends on X86_EXTENDED_PLATFORM
a7f7f624 589 help
758cd94a
JH
590 Enable support for the Goldfish virtual platform used primarily
591 for Android development. Unless you are building for the Android
592 Goldfish emulator say N here.
ddd70cf9 593
c751e17b
TG
594config X86_INTEL_CE
595 bool "CE4100 TV platform"
596 depends on PCI
597 depends on PCI_GODIRECT
6084a6e2 598 depends on X86_IO_APIC
c751e17b
TG
599 depends on X86_32
600 depends on X86_EXTENDED_PLATFORM
37bc9f50 601 select X86_REBOOTFIXUPS
da6b737b
SAS
602 select OF
603 select OF_EARLY_FLATTREE
a7f7f624 604 help
c751e17b
TG
605 Select for the Intel CE media processor (CE4100) SOC.
606 This option compiles in support for the CE4100 SOC for settop
607 boxes and media devices.
608
4cb9b00f 609config X86_INTEL_MID
43605ef1 610 bool "Intel MID platform support"
43605ef1 611 depends on X86_EXTENDED_PLATFORM
edc6bc78 612 depends on X86_PLATFORM_DEVICES
1ea7c673 613 depends on PCI
3fda5bb4 614 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 615 depends on X86_IO_APIC
4cb9b00f 616 select I2C
7c9c3a1e 617 select DW_APB_TIMER
54b34aa0 618 select INTEL_SCU_PCI
a7f7f624 619 help
4cb9b00f
DC
620 Select to build a kernel capable of supporting Intel MID (Mobile
621 Internet Device) platform systems which do not have the PCI legacy
622 interfaces. If you are building for a PC class system say N here.
1ea7c673 623
4cb9b00f
DC
624 Intel MID platforms are based on an Intel processor and chipset which
625 consume less power than most of the x86 derivatives.
43605ef1 626
8bbc2a13
BD
627config X86_INTEL_QUARK
628 bool "Intel Quark platform support"
629 depends on X86_32
630 depends on X86_EXTENDED_PLATFORM
631 depends on X86_PLATFORM_DEVICES
632 depends on X86_TSC
633 depends on PCI
634 depends on PCI_GOANY
635 depends on X86_IO_APIC
636 select IOSF_MBI
637 select INTEL_IMR
9ab6eb51 638 select COMMON_CLK
a7f7f624 639 help
8bbc2a13
BD
640 Select to include support for Quark X1000 SoC.
641 Say Y here if you have a Quark based system such as the Arduino
642 compatible Intel Galileo.
643
3d48aab1
MW
644config X86_INTEL_LPSS
645 bool "Intel Low Power Subsystem Support"
5962dd22 646 depends on X86 && ACPI && PCI
3d48aab1 647 select COMMON_CLK
0f531431 648 select PINCTRL
eebb3e8d 649 select IOSF_MBI
a7f7f624 650 help
3d48aab1
MW
651 Select to build support for Intel Low Power Subsystem such as
652 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
653 things like clock tree (common clock framework) and pincontrol
654 which are needed by the LPSS peripheral drivers.
3d48aab1 655
92082a88
KX
656config X86_AMD_PLATFORM_DEVICE
657 bool "AMD ACPI2Platform devices support"
658 depends on ACPI
659 select COMMON_CLK
660 select PINCTRL
a7f7f624 661 help
92082a88
KX
662 Select to interpret AMD specific ACPI device to platform device
663 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
664 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
665 implemented under PINCTRL subsystem.
666
ced3ce76
DB
667config IOSF_MBI
668 tristate "Intel SoC IOSF Sideband support for SoC platforms"
669 depends on PCI
a7f7f624 670 help
ced3ce76
DB
671 This option enables sideband register access support for Intel SoC
672 platforms. On these platforms the IOSF sideband is used in lieu of
673 MSR's for some register accesses, mostly but not limited to thermal
674 and power. Drivers may query the availability of this device to
675 determine if they need the sideband in order to work on these
676 platforms. The sideband is available on the following SoC products.
677 This list is not meant to be exclusive.
678 - BayTrail
679 - Braswell
680 - Quark
681
682 You should say Y if you are running a kernel on one of these SoC's.
683
ed2226bd
DB
684config IOSF_MBI_DEBUG
685 bool "Enable IOSF sideband access through debugfs"
686 depends on IOSF_MBI && DEBUG_FS
a7f7f624 687 help
ed2226bd
DB
688 Select this option to expose the IOSF sideband access registers (MCR,
689 MDR, MCRX) through debugfs to write and read register information from
690 different units on the SoC. This is most useful for obtaining device
691 state information for debug and analysis. As this is a general access
692 mechanism, users of this option would have specific knowledge of the
693 device they want to access.
694
695 If you don't require the option or are in doubt, say N.
696
c5c606d9
RT
697config X86_RDC321X
698 bool "RDC R-321x SoC"
506f1d07 699 depends on X86_32
c5c606d9
RT
700 depends on X86_EXTENDED_PLATFORM
701 select M486
702 select X86_REBOOTFIXUPS
a7f7f624 703 help
c5c606d9
RT
704 This option is needed for RDC R-321x system-on-chip, also known
705 as R-8610-(G).
706 If you don't have one of these chips, you should say N here.
707
e0c7ae37 708config X86_32_NON_STANDARD
9c398017
IM
709 bool "Support non-standard 32-bit SMP architectures"
710 depends on X86_32 && SMP
c5c606d9 711 depends on X86_EXTENDED_PLATFORM
a7f7f624 712 help
b5660ba7
PA
713 This option compiles in the bigsmp and STA2X11 default
714 subarchitectures. It is intended for a generic binary
715 kernel. If you select them all, kernel will probe it one by
716 one and will fallback to default.
d49c4288 717
c5c606d9 718# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 719
d949f36f 720config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 721 def_bool y
d949f36f
LT
722 # MCE code calls memory_failure():
723 depends on X86_MCE
724 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
725 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
726 depends on X86_64 || !SPARSEMEM
727 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 728
83125a3a
AR
729config STA2X11
730 bool "STA2X11 Companion Chip Support"
731 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
732 select SWIOTLB
733 select MFD_STA2X11
0145071b 734 select GPIOLIB
a7f7f624 735 help
83125a3a
AR
736 This adds support for boards based on the STA2X11 IO-Hub,
737 a.k.a. "ConneXt". The chip is used in place of the standard
738 PC chipset, so all "standard" peripherals are missing. If this
739 option is selected the kernel will still be able to boot on
740 standard PC machines.
741
82148d1d
S
742config X86_32_IRIS
743 tristate "Eurobraille/Iris poweroff module"
744 depends on X86_32
a7f7f624 745 help
82148d1d
S
746 The Iris machines from EuroBraille do not have APM or ACPI support
747 to shut themselves down properly. A special I/O sequence is
748 needed to do so, which is what this module does at
749 kernel shutdown.
750
751 This is only for Iris machines from EuroBraille.
752
753 If unused, say N.
754
ae1e9130 755config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
756 def_bool y
757 prompt "Single-depth WCHAN output"
a87d0914 758 depends on X86
a7f7f624 759 help
506f1d07
SR
760 Calculate simpler /proc/<PID>/wchan values. If this option
761 is disabled then wchan values will recurse back to the
762 caller function. This provides more accurate wchan values,
763 at the expense of slightly more scheduling overhead.
764
765 If in doubt, say "Y".
766
6276a074
BP
767menuconfig HYPERVISOR_GUEST
768 bool "Linux guest support"
a7f7f624 769 help
6276a074
BP
770 Say Y here to enable options for running Linux under various hyper-
771 visors. This option enables basic hypervisor detection and platform
772 setup.
506f1d07 773
6276a074
BP
774 If you say N, all options in this submenu will be skipped and
775 disabled, and Linux guest support won't be built in.
506f1d07 776
6276a074 777if HYPERVISOR_GUEST
506f1d07 778
e61bd94a
EPH
779config PARAVIRT
780 bool "Enable paravirtualization code"
a0e2bf7c 781 depends on HAVE_STATIC_CALL
a7f7f624 782 help
e61bd94a
EPH
783 This changes the kernel so it can modify itself when it is run
784 under a hypervisor, potentially improving performance significantly
785 over full virtualization. However, when run without a hypervisor
786 the kernel is theoretically slower and slightly larger.
787
c00a280a
JG
788config PARAVIRT_XXL
789 bool
790
6276a074
BP
791config PARAVIRT_DEBUG
792 bool "paravirt-ops debugging"
793 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 794 help
6276a074
BP
795 Enable to debug paravirt_ops internals. Specifically, BUG if
796 a paravirt_op is missing when it is called.
797
b4ecc126
JF
798config PARAVIRT_SPINLOCKS
799 bool "Paravirtualization layer for spinlocks"
6ea30386 800 depends on PARAVIRT && SMP
a7f7f624 801 help
b4ecc126
JF
802 Paravirtualized spinlocks allow a pvops backend to replace the
803 spinlock implementation with something virtualization-friendly
804 (for example, block the virtual CPU rather than spinning).
805
4c4e4f61
R
806 It has a minimal impact on native kernels and gives a nice performance
807 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 808
4c4e4f61 809 If you are unsure how to answer this question, answer Y.
b4ecc126 810
ecca2502
ZY
811config X86_HV_CALLBACK_VECTOR
812 def_bool n
813
6276a074 814source "arch/x86/xen/Kconfig"
7af192c9 815
6276a074
BP
816config KVM_GUEST
817 bool "KVM Guest support (including kvmclock)"
818 depends on PARAVIRT
819 select PARAVIRT_CLOCK
a1c4423b 820 select ARCH_CPUIDLE_HALTPOLL
b1d40575 821 select X86_HV_CALLBACK_VECTOR
6276a074 822 default y
a7f7f624 823 help
6276a074
BP
824 This option enables various optimizations for running under the KVM
825 hypervisor. It includes a paravirtualized clock, so that instead
826 of relying on a PIT (or probably other) emulation by the
827 underlying device model, the host provides the guest with
828 timing infrastructure such as time of day, and system time
506f1d07 829
a1c4423b 830config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
831 def_bool n
832 prompt "Disable host haltpoll when loading haltpoll driver"
833 help
a1c4423b
MT
834 If virtualized under KVM, disable host haltpoll.
835
7733607f
MW
836config PVH
837 bool "Support for running PVH guests"
a7f7f624 838 help
7733607f
MW
839 This option enables the PVH entry point for guest virtual machines
840 as specified in the x86/HVM direct boot ABI.
841
6276a074
BP
842config PARAVIRT_TIME_ACCOUNTING
843 bool "Paravirtual steal time accounting"
844 depends on PARAVIRT
a7f7f624 845 help
6276a074
BP
846 Select this option to enable fine granularity task steal time
847 accounting. Time spent executing other tasks in parallel with
848 the current vCPU is discounted from the vCPU power. To account for
849 that, there can be a small performance impact.
850
851 If in doubt, say N here.
852
853config PARAVIRT_CLOCK
854 bool
97349135 855
4a362601
JK
856config JAILHOUSE_GUEST
857 bool "Jailhouse non-root cell support"
abde587b 858 depends on X86_64 && PCI
87e65d05 859 select X86_PM_TIMER
a7f7f624 860 help
4a362601
JK
861 This option allows to run Linux as guest in a Jailhouse non-root
862 cell. You can leave this option disabled if you only want to start
863 Jailhouse and run Linux afterwards in the root cell.
864
ec7972c9
ZY
865config ACRN_GUEST
866 bool "ACRN Guest support"
867 depends on X86_64
498ad393 868 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
869 help
870 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
871 a flexible, lightweight reference open-source hypervisor, built with
872 real-time and safety-criticality in mind. It is built for embedded
873 IOT with small footprint and real-time features. More details can be
874 found in https://projectacrn.org/.
875
59bd54a8
KS
876config INTEL_TDX_GUEST
877 bool "Intel TDX (Trust Domain Extensions) - Guest Support"
878 depends on X86_64 && CPU_SUP_INTEL
879 depends on X86_X2APIC
75d090fd 880 depends on EFI_STUB
41394e33 881 select ARCH_HAS_CC_PLATFORM
968b4931 882 select X86_MEM_ENCRYPT
77a512e3 883 select X86_MCE
75d090fd 884 select UNACCEPTED_MEMORY
59bd54a8
KS
885 help
886 Support running as a guest under Intel TDX. Without this support,
887 the guest kernel can not boot or run under TDX.
888 TDX includes memory encryption and integrity capabilities
889 which protect the confidentiality and integrity of guest
890 memory contents and CPU state. TDX guests are protected from
891 some attacks from the VMM.
892
758cd94a 893endif # HYPERVISOR_GUEST
97349135 894
506f1d07
SR
895source "arch/x86/Kconfig.cpu"
896
897config HPET_TIMER
3c2362e6 898 def_bool X86_64
506f1d07 899 prompt "HPET Timer Support" if X86_32
a7f7f624 900 help
8f9ca475
IM
901 Use the IA-PC HPET (High Precision Event Timer) to manage
902 time in preference to the PIT and RTC, if a HPET is
903 present.
904 HPET is the next generation timer replacing legacy 8254s.
905 The HPET provides a stable time base on SMP
906 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
907 as it is off-chip. The interface used is documented
908 in the HPET spec, revision 1.
506f1d07 909
8f9ca475
IM
910 You can safely choose Y here. However, HPET will only be
911 activated if the platform and the BIOS support this feature.
912 Otherwise the 8254 will be used for timing services.
506f1d07 913
8f9ca475 914 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
915
916config HPET_EMULATE_RTC
3c2362e6 917 def_bool y
3228e1dc 918 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 919
6a108a14 920# Mark as expert because too many people got it wrong.
506f1d07 921# The code disables itself when not needed.
7ae9392c
TP
922config DMI
923 default y
cf074402 924 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 925 bool "Enable DMI scanning" if EXPERT
a7f7f624 926 help
7ae9392c
TP
927 Enabled scanning of DMI to identify machine quirks. Say Y
928 here unless you have verified that your setup is not
929 affected by entries in the DMI blacklist. Required by PNP
930 BIOS code.
931
506f1d07 932config GART_IOMMU
38901f1c 933 bool "Old AMD GART IOMMU support"
2f9237d4 934 select DMA_OPS
a4ce5a48 935 select IOMMU_HELPER
506f1d07 936 select SWIOTLB
23ac4ae8 937 depends on X86_64 && PCI && AMD_NB
a7f7f624 938 help
ced3c42c
IM
939 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
940 GART based hardware IOMMUs.
941
942 The GART supports full DMA access for devices with 32-bit access
943 limitations, on systems with more than 3 GB. This is usually needed
944 for USB, sound, many IDE/SATA chipsets and some other devices.
945
946 Newer systems typically have a modern AMD IOMMU, supported via
947 the CONFIG_AMD_IOMMU=y config option.
948
949 In normal configurations this driver is only active when needed:
950 there's more than 3 GB of memory and the system contains a
951 32-bit limited device.
952
953 If unsure, say Y.
506f1d07 954
8b766b0f
MS
955config BOOT_VESA_SUPPORT
956 bool
957 help
958 If true, at least one selected framebuffer driver can take advantage
959 of VESA video modes set at an early boot stage via the vga= parameter.
506f1d07 960
1184dc2f 961config MAXSMP
ddb0c5a6 962 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 963 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 964 select CPUMASK_OFFSTACK
a7f7f624 965 help
ddb0c5a6 966 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 967 If unsure, say N.
506f1d07 968
aec6487e
IM
969#
970# The maximum number of CPUs supported:
971#
972# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
973# and which can be configured interactively in the
974# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
975#
976# The ranges are different on 32-bit and 64-bit kernels, depending on
977# hardware capabilities and scalability features of the kernel.
978#
979# ( If MAXSMP is enabled we just use the highest possible value and disable
980# interactive configuration. )
981#
982
983config NR_CPUS_RANGE_BEGIN
a0d0bb4d 984 int
aec6487e
IM
985 default NR_CPUS_RANGE_END if MAXSMP
986 default 1 if !SMP
987 default 2
a0d0bb4d 988
aec6487e 989config NR_CPUS_RANGE_END
a0d0bb4d 990 int
aec6487e
IM
991 depends on X86_32
992 default 64 if SMP && X86_BIGSMP
993 default 8 if SMP && !X86_BIGSMP
994 default 1 if !SMP
a0d0bb4d 995
aec6487e 996config NR_CPUS_RANGE_END
a0d0bb4d 997 int
aec6487e 998 depends on X86_64
1edae1ae
SW
999 default 8192 if SMP && CPUMASK_OFFSTACK
1000 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 1001 default 1 if !SMP
a0d0bb4d 1002
aec6487e 1003config NR_CPUS_DEFAULT
a0d0bb4d
RD
1004 int
1005 depends on X86_32
aec6487e
IM
1006 default 32 if X86_BIGSMP
1007 default 8 if SMP
1008 default 1 if !SMP
a0d0bb4d 1009
aec6487e 1010config NR_CPUS_DEFAULT
a0d0bb4d
RD
1011 int
1012 depends on X86_64
aec6487e
IM
1013 default 8192 if MAXSMP
1014 default 64 if SMP
1015 default 1 if !SMP
a0d0bb4d 1016
506f1d07 1017config NR_CPUS
36f5101a 1018 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
1019 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1020 default NR_CPUS_DEFAULT
a7f7f624 1021 help
506f1d07 1022 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1023 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1024 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1025 minimum value which makes sense is 2.
1026
aec6487e
IM
1027 This is purely to save memory: each supported CPU adds about 8KB
1028 to the kernel image.
506f1d07 1029
66558b73
TC
1030config SCHED_CLUSTER
1031 bool "Cluster scheduler support"
1032 depends on SMP
1033 default y
1034 help
1035 Cluster scheduler support improves the CPU scheduler's decision
1036 making when dealing with machines that have clusters of CPUs.
1037 Cluster usually means a couple of CPUs which are placed closely
1038 by sharing mid-level caches, last-level cache tags or internal
1039 busses.
1040
506f1d07 1041config SCHED_SMT
dbe73364 1042 def_bool y if SMP
506f1d07
SR
1043
1044config SCHED_MC
3c2362e6
HH
1045 def_bool y
1046 prompt "Multi-core scheduler support"
c8e56d20 1047 depends on SMP
a7f7f624 1048 help
506f1d07
SR
1049 Multi-core scheduler support improves the CPU scheduler's decision
1050 making when dealing with multi-core CPU chips at a cost of slightly
1051 increased overhead in some places. If unsure say N here.
1052
de966cf4
TC
1053config SCHED_MC_PRIO
1054 bool "CPU core priorities scheduler support"
0a21fc12
IM
1055 depends on SCHED_MC && CPU_SUP_INTEL
1056 select X86_INTEL_PSTATE
1057 select CPU_FREQ
de966cf4 1058 default y
a7f7f624 1059 help
0a21fc12
IM
1060 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1061 core ordering determined at manufacturing time, which allows
1062 certain cores to reach higher turbo frequencies (when running
1063 single threaded workloads) than others.
de966cf4 1064
0a21fc12
IM
1065 Enabling this kernel feature teaches the scheduler about
1066 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1067 scheduler's CPU selection logic accordingly, so that higher
1068 overall system performance can be achieved.
de966cf4 1069
0a21fc12 1070 This feature will have no effect on CPUs without this feature.
de966cf4 1071
0a21fc12 1072 If unsure say Y here.
5e76b2ab 1073
30b8b006 1074config UP_LATE_INIT
b03b016f
KK
1075 def_bool y
1076 depends on !SMP && X86_LOCAL_APIC
30b8b006 1077
506f1d07 1078config X86_UP_APIC
50849eef
JB
1079 bool "Local APIC support on uniprocessors" if !PCI_MSI
1080 default PCI_MSI
38a1dfda 1081 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1082 help
506f1d07
SR
1083 A local APIC (Advanced Programmable Interrupt Controller) is an
1084 integrated interrupt controller in the CPU. If you have a single-CPU
1085 system which has a processor with a local APIC, you can say Y here to
1086 enable and use it. If you say Y here even though your machine doesn't
1087 have a local APIC, then the kernel will still run with no slowdown at
1088 all. The local APIC supports CPU-generated self-interrupts (timer,
1089 performance counters), and the NMI watchdog which detects hard
1090 lockups.
1091
1092config X86_UP_IOAPIC
1093 bool "IO-APIC support on uniprocessors"
1094 depends on X86_UP_APIC
a7f7f624 1095 help
506f1d07
SR
1096 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1097 SMP-capable replacement for PC-style interrupt controllers. Most
1098 SMP systems and many recent uniprocessor systems have one.
1099
1100 If you have a single-CPU system with an IO-APIC, you can say Y here
1101 to use it. If you say Y here even though your machine doesn't have
1102 an IO-APIC, then the kernel will still run with no slowdown at all.
1103
1104config X86_LOCAL_APIC
3c2362e6 1105 def_bool y
0dbc6078 1106 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1107 select IRQ_DOMAIN_HIERARCHY
506f1d07
SR
1108
1109config X86_IO_APIC
b1da1e71
JB
1110 def_bool y
1111 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1112
41b9eb26
SA
1113config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1114 bool "Reroute for broken boot IRQs"
41b9eb26 1115 depends on X86_IO_APIC
a7f7f624 1116 help
41b9eb26
SA
1117 This option enables a workaround that fixes a source of
1118 spurious interrupts. This is recommended when threaded
1119 interrupt handling is used on systems where the generation of
1120 superfluous "boot interrupts" cannot be disabled.
1121
1122 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1123 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1124 kernel does during interrupt handling). On chipsets where this
1125 boot IRQ generation cannot be disabled, this workaround keeps
1126 the original IRQ line masked so that only the equivalent "boot
1127 IRQ" is delivered to the CPUs. The workaround also tells the
1128 kernel to set up the IRQ handler on the boot IRQ line. In this
1129 way only one interrupt is delivered to the kernel. Otherwise
1130 the spurious second interrupt may cause the kernel to bring
1131 down (vital) interrupt lines.
1132
1133 Only affects "broken" chipsets. Interrupt sharing may be
1134 increased on these systems.
1135
506f1d07 1136config X86_MCE
bab9bc65 1137 bool "Machine Check / overheating reporting"
648ed940 1138 select GENERIC_ALLOCATOR
e57dbaf7 1139 default y
a7f7f624 1140 help
bab9bc65
AK
1141 Machine Check support allows the processor to notify the
1142 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1143 The action the kernel takes depends on the severity of the problem,
bab9bc65 1144 ranging from warning messages to halting the machine.
4efc0670 1145
5de97c9f
TL
1146config X86_MCELOG_LEGACY
1147 bool "Support for deprecated /dev/mcelog character device"
1148 depends on X86_MCE
a7f7f624 1149 help
5de97c9f
TL
1150 Enable support for /dev/mcelog which is needed by the old mcelog
1151 userspace logging daemon. Consider switching to the new generation
1152 rasdaemon solution.
1153
506f1d07 1154config X86_MCE_INTEL
3c2362e6
HH
1155 def_bool y
1156 prompt "Intel MCE features"
c1ebf835 1157 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1158 help
758cd94a
JH
1159 Additional support for intel specific MCE features such as
1160 the thermal monitor.
506f1d07
SR
1161
1162config X86_MCE_AMD
3c2362e6
HH
1163 def_bool y
1164 prompt "AMD MCE features"
f5382de9 1165 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
a7f7f624 1166 help
758cd94a
JH
1167 Additional support for AMD specific MCE features such as
1168 the DRAM Error Threshold.
506f1d07 1169
4efc0670 1170config X86_ANCIENT_MCE
6fc108a0 1171 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1172 depends on X86_32 && X86_MCE
a7f7f624 1173 help
cd13adcc 1174 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1175 systems. These typically need to be enabled explicitly on the command
cd13adcc 1176 line.
4efc0670 1177
b2762686
AK
1178config X86_MCE_THRESHOLD
1179 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1180 def_bool y
b2762686 1181
ea149b36 1182config X86_MCE_INJECT
bc8e80d5 1183 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1184 tristate "Machine check injector support"
a7f7f624 1185 help
ea149b36
AK
1186 Provide support for injecting machine checks for testing purposes.
1187 If you don't know what a machine check is and you don't do kernel
1188 QA it is safe to say n.
1189
07dc900e 1190source "arch/x86/events/Kconfig"
e633c65a 1191
5aef51c3 1192config X86_LEGACY_VM86
1e642812 1193 bool "Legacy VM86 support"
506f1d07 1194 depends on X86_32
a7f7f624 1195 help
5aef51c3
AL
1196 This option allows user programs to put the CPU into V8086
1197 mode, which is an 80286-era approximation of 16-bit real mode.
1198
1199 Some very old versions of X and/or vbetool require this option
1200 for user mode setting. Similarly, DOSEMU will use it if
1201 available to accelerate real mode DOS programs. However, any
1202 recent version of DOSEMU, X, or vbetool should be fully
1203 functional even without kernel VM86 support, as they will all
1e642812
IM
1204 fall back to software emulation. Nevertheless, if you are using
1205 a 16-bit DOS program where 16-bit performance matters, vm86
1206 mode might be faster than emulation and you might want to
1207 enable this option.
5aef51c3 1208
1e642812
IM
1209 Note that any app that works on a 64-bit kernel is unlikely to
1210 need this option, as 64-bit kernels don't, and can't, support
1211 V8086 mode. This option is also unrelated to 16-bit protected
1212 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1213
1e642812
IM
1214 Enabling this option increases the complexity of the kernel
1215 and slows down exception handling a tiny bit.
5aef51c3 1216
1e642812 1217 If unsure, say N here.
5aef51c3
AL
1218
1219config VM86
b03b016f
KK
1220 bool
1221 default X86_LEGACY_VM86
34273f41
PA
1222
1223config X86_16BIT
1224 bool "Enable support for 16-bit segments" if EXPERT
1225 default y
a5b9e5a2 1226 depends on MODIFY_LDT_SYSCALL
a7f7f624 1227 help
34273f41
PA
1228 This option is required by programs like Wine to run 16-bit
1229 protected mode legacy code on x86 processors. Disabling
1230 this option saves about 300 bytes on i386, or around 6K text
1231 plus 16K runtime memory on x86-64,
1232
1233config X86_ESPFIX32
1234 def_bool y
1235 depends on X86_16BIT && X86_32
506f1d07 1236
197725de
PA
1237config X86_ESPFIX64
1238 def_bool y
34273f41 1239 depends on X86_16BIT && X86_64
506f1d07 1240
1ad83c85 1241config X86_VSYSCALL_EMULATION
b03b016f
KK
1242 bool "Enable vsyscall emulation" if EXPERT
1243 default y
1244 depends on X86_64
a7f7f624 1245 help
758cd94a
JH
1246 This enables emulation of the legacy vsyscall page. Disabling
1247 it is roughly equivalent to booting with vsyscall=none, except
1248 that it will also disable the helpful warning if a program
1249 tries to use a vsyscall. With this option set to N, offending
1250 programs will just segfault, citing addresses of the form
1251 0xffffffffff600?00.
1ad83c85 1252
758cd94a
JH
1253 This option is required by many programs built before 2013, and
1254 care should be used even with newer programs if set to N.
1ad83c85 1255
758cd94a
JH
1256 Disabling this option saves about 7K of kernel size and
1257 possibly 4K of additional runtime pagetable memory.
1ad83c85 1258
111e7b15
TG
1259config X86_IOPL_IOPERM
1260 bool "IOPERM and IOPL Emulation"
a24ca997 1261 default y
a7f7f624 1262 help
111e7b15
TG
1263 This enables the ioperm() and iopl() syscalls which are necessary
1264 for legacy applications.
1265
c8137ace
TG
1266 Legacy IOPL support is an overbroad mechanism which allows user
1267 space aside of accessing all 65536 I/O ports also to disable
1268 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1269 capabilities and permission from potentially active security
1270 modules.
1271
1272 The emulation restricts the functionality of the syscall to
1273 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1274 ability to disable interrupts from user space which would be
1275 granted if the hardware IOPL mechanism would be used.
c8137ace 1276
506f1d07
SR
1277config TOSHIBA
1278 tristate "Toshiba Laptop support"
1279 depends on X86_32
a7f7f624 1280 help
506f1d07
SR
1281 This adds a driver to safely access the System Management Mode of
1282 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1283 not work on models with a Phoenix BIOS. The System Management Mode
1284 is used to set the BIOS and power saving options on Toshiba portables.
1285
1286 For information on utilities to make use of this driver see the
1287 Toshiba Linux utilities web site at:
1288 <http://www.buzzard.org.uk/toshiba/>.
1289
1290 Say Y if you intend to run this kernel on a Toshiba portable.
1291 Say N otherwise.
1292
506f1d07 1293config X86_REBOOTFIXUPS
9ba16087
JB
1294 bool "Enable X86 board specific fixups for reboot"
1295 depends on X86_32
a7f7f624 1296 help
506f1d07
SR
1297 This enables chipset and/or board specific fixups to be done
1298 in order to get reboot to work correctly. This is only needed on
1299 some combinations of hardware and BIOS. The symptom, for which
1300 this config is intended, is when reboot ends with a stalled/hung
1301 system.
1302
1303 Currently, the only fixup is for the Geode machines using
5e3a77e9 1304 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1305
1306 Say Y if you want to enable the fixup. Currently, it's safe to
1307 enable this option even if you don't need it.
1308 Say N otherwise.
1309
1310config MICROCODE
9a2bc335
BP
1311 bool "CPU microcode loading support"
1312 default y
80030e3d 1313 depends on CPU_SUP_AMD || CPU_SUP_INTEL
a7f7f624 1314 help
506f1d07 1315 If you say Y here, you will be able to update the microcode on
5f9c01aa
BP
1316 Intel and AMD processors. The Intel support is for the IA32 family,
1317 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1318 AMD support is for families 0x10 and later. You will obviously need
1319 the actual microcode binary data itself which is not shipped with
1320 the Linux kernel.
1321
1322 The preferred method to load microcode from a detached initrd is described
ff61f079 1323 in Documentation/arch/x86/microcode.rst. For that you need to enable
5f9c01aa
BP
1324 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1325 initrd for microcode blobs.
1326
c508c46e
BG
1327 In addition, you can build the microcode into the kernel. For that you
1328 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1329 config option.
506f1d07 1330
8d86f390 1331config MICROCODE_INTEL
e43f6e67 1332 bool "Intel microcode loading support"
9c55d99e 1333 depends on CPU_SUP_INTEL && MICROCODE
8f9ca475 1334 default MICROCODE
a7f7f624 1335 help
8f9ca475
IM
1336 This options enables microcode patch loading support for Intel
1337 processors.
1338
b8989db9
A
1339 For the current Intel microcode data package go to
1340 <https://downloadcenter.intel.com> and search for
1341 'Linux Processor Microcode Data File'.
8d86f390 1342
80cc9f10 1343config MICROCODE_AMD
e43f6e67 1344 bool "AMD microcode loading support"
9c55d99e 1345 depends on CPU_SUP_AMD && MICROCODE
a7f7f624 1346 help
8f9ca475
IM
1347 If you select this option, microcode patch loading support for AMD
1348 processors will be enabled.
80cc9f10 1349
a77a94f8
BP
1350config MICROCODE_LATE_LOADING
1351 bool "Late microcode loading (DANGEROUS)"
c02f48e0 1352 default n
506f1d07 1353 depends on MICROCODE
a7f7f624 1354 help
a77a94f8
BP
1355 Loading microcode late, when the system is up and executing instructions
1356 is a tricky business and should be avoided if possible. Just the sequence
1357 of synchronizing all cores and SMT threads is one fragile dance which does
1358 not guarantee that cores might not softlock after the loading. Therefore,
1359 use this at your own risk. Late loading taints the kernel too.
506f1d07
SR
1360
1361config X86_MSR
1362 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1363 help
506f1d07
SR
1364 This device gives privileged processes access to the x86
1365 Model-Specific Registers (MSRs). It is a character device with
1366 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1367 MSR accesses are directed to a specific CPU on multi-processor
1368 systems.
1369
1370config X86_CPUID
1371 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1372 help
506f1d07
SR
1373 This device gives processes access to the x86 CPUID instruction to
1374 be executed on a specific processor. It is a character device
1375 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1376 /dev/cpu/31/cpuid.
1377
1378choice
1379 prompt "High Memory Support"
6fc108a0 1380 default HIGHMEM4G
506f1d07
SR
1381 depends on X86_32
1382
1383config NOHIGHMEM
1384 bool "off"
a7f7f624 1385 help
506f1d07
SR
1386 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1387 However, the address space of 32-bit x86 processors is only 4
1388 Gigabytes large. That means that, if you have a large amount of
1389 physical memory, not all of it can be "permanently mapped" by the
1390 kernel. The physical memory that's not permanently mapped is called
1391 "high memory".
1392
1393 If you are compiling a kernel which will never run on a machine with
1394 more than 1 Gigabyte total physical RAM, answer "off" here (default
1395 choice and suitable for most users). This will result in a "3GB/1GB"
1396 split: 3GB are mapped so that each process sees a 3GB virtual memory
1397 space and the remaining part of the 4GB virtual memory space is used
1398 by the kernel to permanently map as much physical memory as
1399 possible.
1400
1401 If the machine has between 1 and 4 Gigabytes physical RAM, then
1402 answer "4GB" here.
1403
1404 If more than 4 Gigabytes is used then answer "64GB" here. This
1405 selection turns Intel PAE (Physical Address Extension) mode on.
1406 PAE implements 3-level paging on IA32 processors. PAE is fully
1407 supported by Linux, PAE mode is implemented on all recent Intel
1408 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1409 then the kernel will not boot on CPUs that don't support PAE!
1410
1411 The actual amount of total physical memory will either be
1412 auto detected or can be forced by using a kernel command line option
1413 such as "mem=256M". (Try "man bootparam" or see the documentation of
1414 your boot loader (lilo or loadlin) about how to pass options to the
1415 kernel at boot time.)
1416
1417 If unsure, say "off".
1418
1419config HIGHMEM4G
1420 bool "4GB"
a7f7f624 1421 help
506f1d07
SR
1422 Select this if you have a 32-bit processor and between 1 and 4
1423 gigabytes of physical RAM.
1424
1425config HIGHMEM64G
1426 bool "64GB"
225bac2d 1427 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
506f1d07 1428 select X86_PAE
a7f7f624 1429 help
506f1d07
SR
1430 Select this if you have a 32-bit processor and more than 4
1431 gigabytes of physical RAM.
1432
1433endchoice
1434
1435choice
6a108a14 1436 prompt "Memory split" if EXPERT
506f1d07
SR
1437 default VMSPLIT_3G
1438 depends on X86_32
a7f7f624 1439 help
506f1d07
SR
1440 Select the desired split between kernel and user memory.
1441
1442 If the address range available to the kernel is less than the
1443 physical memory installed, the remaining memory will be available
1444 as "high memory". Accessing high memory is a little more costly
1445 than low memory, as it needs to be mapped into the kernel first.
1446 Note that increasing the kernel address space limits the range
1447 available to user programs, making the address space there
1448 tighter. Selecting anything other than the default 3G/1G split
1449 will also likely make your kernel incompatible with binary-only
1450 kernel modules.
1451
1452 If you are not absolutely sure what you are doing, leave this
1453 option alone!
1454
1455 config VMSPLIT_3G
1456 bool "3G/1G user/kernel split"
1457 config VMSPLIT_3G_OPT
1458 depends on !X86_PAE
1459 bool "3G/1G user/kernel split (for full 1G low memory)"
1460 config VMSPLIT_2G
1461 bool "2G/2G user/kernel split"
1462 config VMSPLIT_2G_OPT
1463 depends on !X86_PAE
1464 bool "2G/2G user/kernel split (for full 2G low memory)"
1465 config VMSPLIT_1G
1466 bool "1G/3G user/kernel split"
1467endchoice
1468
1469config PAGE_OFFSET
1470 hex
1471 default 0xB0000000 if VMSPLIT_3G_OPT
1472 default 0x80000000 if VMSPLIT_2G
1473 default 0x78000000 if VMSPLIT_2G_OPT
1474 default 0x40000000 if VMSPLIT_1G
1475 default 0xC0000000
1476 depends on X86_32
1477
1478config HIGHMEM
3c2362e6 1479 def_bool y
506f1d07 1480 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1481
1482config X86_PAE
9ba16087 1483 bool "PAE (Physical Address Extension) Support"
506f1d07 1484 depends on X86_32 && !HIGHMEM4G
d4a451d5 1485 select PHYS_ADDR_T_64BIT
9d99c712 1486 select SWIOTLB
a7f7f624 1487 help
506f1d07
SR
1488 PAE is required for NX support, and furthermore enables
1489 larger swapspace support for non-overcommit purposes. It
1490 has the cost of more pagetable lookup overhead, and also
1491 consumes more pagetable space per process.
1492
77ef56e4
KS
1493config X86_5LEVEL
1494 bool "Enable 5-level page tables support"
18ec1eaf 1495 default y
eedb92ab 1496 select DYNAMIC_MEMORY_LAYOUT
162434e7 1497 select SPARSEMEM_VMEMMAP
77ef56e4 1498 depends on X86_64
a7f7f624 1499 help
77ef56e4 1500 5-level paging enables access to larger address space:
54628de6 1501 up to 128 PiB of virtual address space and 4 PiB of
77ef56e4
KS
1502 physical address space.
1503
1504 It will be supported by future Intel CPUs.
1505
6657fca0
KS
1506 A kernel with the option enabled can be booted on machines that
1507 support 4- or 5-level paging.
77ef56e4 1508
ff61f079 1509 See Documentation/arch/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1510 information.
1511
1512 Say N if unsure.
1513
10971ab2 1514config X86_DIRECT_GBPAGES
e5008abe 1515 def_bool y
2e1da13f 1516 depends on X86_64
a7f7f624 1517 help
10971ab2
IM
1518 Certain kernel features effectively disable kernel
1519 linear 1 GB mappings (even if the CPU otherwise
1520 supports them), so don't confuse the user by printing
1521 that we have them enabled.
9e899816 1522
5c280cf6
TG
1523config X86_CPA_STATISTICS
1524 bool "Enable statistic for Change Page Attribute"
1525 depends on DEBUG_FS
a7f7f624 1526 help
b75baaf3 1527 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1528 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1529 page mappings when mapping protections are changed.
1530
20f07a04
KS
1531config X86_MEM_ENCRYPT
1532 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1533 select DYNAMIC_PHYSICAL_MASK
20f07a04
KS
1534 def_bool n
1535
7744ccdb
TL
1536config AMD_MEM_ENCRYPT
1537 bool "AMD Secure Memory Encryption (SME) support"
1538 depends on X86_64 && CPU_SUP_AMD
6c321179 1539 depends on EFI_STUB
82fef0ad 1540 select DMA_COHERENT_POOL
ce9084ba 1541 select ARCH_USE_MEMREMAP_PROT
597cfe48 1542 select INSTRUCTION_DECODER
aa5a4611 1543 select ARCH_HAS_CC_PLATFORM
20f07a04 1544 select X86_MEM_ENCRYPT
6c321179 1545 select UNACCEPTED_MEMORY
a7f7f624 1546 help
7744ccdb
TL
1547 Say yes to enable support for the encryption of system memory.
1548 This requires an AMD processor that supports Secure Memory
1549 Encryption (SME).
1550
1551config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1552 bool "Activate AMD Secure Memory Encryption (SME) by default"
7744ccdb 1553 depends on AMD_MEM_ENCRYPT
a7f7f624 1554 help
7744ccdb
TL
1555 Say yes to have system memory encrypted by default if running on
1556 an AMD processor that supports Secure Memory Encryption (SME).
1557
1558 If set to Y, then the encryption of system memory can be
1559 deactivated with the mem_encrypt=off command line option.
1560
1561 If set to N, then the encryption of system memory can be
1562 activated with the mem_encrypt=on command line option.
1563
506f1d07
SR
1564# Common NUMA Features
1565config NUMA
e133f6ea 1566 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1567 depends on SMP
b5660ba7
PA
1568 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1569 default y if X86_BIGSMP
7ecd19cf 1570 select USE_PERCPU_NUMA_NODE_ID
a7f7f624 1571 help
e133f6ea 1572 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1573
506f1d07
SR
1574 The kernel will try to allocate memory used by a CPU on the
1575 local memory controller of the CPU and add some more
1576 NUMA awareness to the kernel.
1577
c280ea5e 1578 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1579 (or later), AMD Opteron, or EM64T NUMA.
1580
b5660ba7 1581 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1582 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1583
1584 Otherwise, you should say N.
506f1d07 1585
eec1d4fa 1586config AMD_NUMA
3c2362e6
HH
1587 def_bool y
1588 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1589 depends on X86_64 && NUMA && PCI
a7f7f624 1590 help
eec1d4fa
HR
1591 Enable AMD NUMA node topology detection. You should say Y here if
1592 you have a multi processor AMD system. This uses an old method to
1593 read the NUMA configuration directly from the builtin Northbridge
1594 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1595 which also takes priority if both are compiled in.
506f1d07
SR
1596
1597config X86_64_ACPI_NUMA
3c2362e6
HH
1598 def_bool y
1599 prompt "ACPI NUMA detection"
506f1d07
SR
1600 depends on X86_64 && NUMA && ACPI && PCI
1601 select ACPI_NUMA
a7f7f624 1602 help
506f1d07
SR
1603 Enable ACPI SRAT based node topology detection.
1604
1605config NUMA_EMU
1606 bool "NUMA emulation"
1b7e03ef 1607 depends on NUMA
a7f7f624 1608 help
506f1d07
SR
1609 Enable NUMA emulation. A flat machine will be split
1610 into virtual nodes when booted with "numa=fake=N", where N is the
1611 number of nodes. This is only useful for debugging.
1612
1613config NODES_SHIFT
d25e26b6 1614 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1615 range 1 10
1616 default "10" if MAXSMP
506f1d07 1617 default "6" if X86_64
506f1d07 1618 default "3"
a9ee6cf5 1619 depends on NUMA
a7f7f624 1620 help
1184dc2f 1621 Specify the maximum number of NUMA Nodes available on the target
692105b8 1622 system. Increases memory reserved to accommodate various tables.
506f1d07 1623
506f1d07
SR
1624config ARCH_FLATMEM_ENABLE
1625 def_bool y
3b16651f 1626 depends on X86_32 && !NUMA
506f1d07 1627
506f1d07
SR
1628config ARCH_SPARSEMEM_ENABLE
1629 def_bool y
6ea30386 1630 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1631 select SPARSEMEM_STATIC if X86_32
1632 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1633
3b16651f 1634config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1635 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1636
506f1d07
SR
1637config ARCH_SELECT_MEMORY_MODEL
1638 def_bool y
4eda2bc3 1639 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
506f1d07
SR
1640
1641config ARCH_MEMORY_PROBE
a0842b70 1642 bool "Enable sysfs memory/probe interface"
5c11f00b 1643 depends on MEMORY_HOTPLUG
a0842b70
TK
1644 help
1645 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1646 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1647 If you are unsure how to answer this question, answer N.
506f1d07 1648
3b16651f
TH
1649config ARCH_PROC_KCORE_TEXT
1650 def_bool y
1651 depends on X86_64 && PROC_KCORE
1652
a29815a3 1653config ILLEGAL_POINTER_VALUE
b03b016f
KK
1654 hex
1655 default 0 if X86_32
1656 default 0xdead000000000000 if X86_64
a29815a3 1657
7a67832c
DW
1658config X86_PMEM_LEGACY_DEVICE
1659 bool
1660
ec776ef6 1661config X86_PMEM_LEGACY
7a67832c 1662 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1663 depends on PHYS_ADDR_T_64BIT
1664 depends on BLK_DEV
7a67832c 1665 select X86_PMEM_LEGACY_DEVICE
7b27a862 1666 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1667 select LIBNVDIMM
ec776ef6
CH
1668 help
1669 Treat memory marked using the non-standard e820 type of 12 as used
1670 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1671 The kernel will offer these regions to the 'pmem' driver so
1672 they can be used for persistent storage.
1673
1674 Say Y if unsure.
1675
506f1d07
SR
1676config HIGHPTE
1677 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1678 depends on HIGHMEM
a7f7f624 1679 help
506f1d07
SR
1680 The VM uses one page table entry for each page of physical memory.
1681 For systems with a lot of RAM, this can be wasteful of precious
1682 low memory. Setting this option will put user-space page table
1683 entries in high memory.
1684
9f077871 1685config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1686 bool "Check for low memory corruption"
a7f7f624 1687 help
8f9ca475
IM
1688 Periodically check for memory corruption in low memory, which
1689 is suspected to be caused by BIOS. Even when enabled in the
1690 configuration, it is disabled at runtime. Enable it by
1691 setting "memory_corruption_check=1" on the kernel command
1692 line. By default it scans the low 64k of memory every 60
1693 seconds; see the memory_corruption_check_size and
1694 memory_corruption_check_period parameters in
8c27ceff 1695 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1696
1697 When enabled with the default parameters, this option has
1698 almost no overhead, as it reserves a relatively small amount
1699 of memory and scans it infrequently. It both detects corruption
1700 and prevents it from affecting the running system.
1701
1702 It is, however, intended as a diagnostic tool; if repeatable
1703 BIOS-originated corruption always affects the same memory,
1704 you can use memmap= to prevent the kernel from using that
1705 memory.
9f077871 1706
c885df50 1707config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1708 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1709 depends on X86_CHECK_BIOS_CORRUPTION
1710 default y
a7f7f624 1711 help
8f9ca475
IM
1712 Set whether the default state of memory_corruption_check is
1713 on or off.
c885df50 1714
506f1d07
SR
1715config MATH_EMULATION
1716 bool
a5b9e5a2 1717 depends on MODIFY_LDT_SYSCALL
87d6021b 1718 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1719 help
506f1d07
SR
1720 Linux can emulate a math coprocessor (used for floating point
1721 operations) if you don't have one. 486DX and Pentium processors have
1722 a math coprocessor built in, 486SX and 386 do not, unless you added
1723 a 487DX or 387, respectively. (The messages during boot time can
1724 give you some hints here ["man dmesg"].) Everyone needs either a
1725 coprocessor or this emulation.
1726
1727 If you don't have a math coprocessor, you need to say Y here; if you
1728 say Y here even though you have a coprocessor, the coprocessor will
1729 be used nevertheless. (This behavior can be changed with the kernel
1730 command line option "no387", which comes handy if your coprocessor
1731 is broken. Try "man bootparam" or see the documentation of your boot
1732 loader (lilo or loadlin) about how to pass options to the kernel at
1733 boot time.) This means that it is a good idea to say Y here if you
1734 intend to use this kernel on different machines.
1735
1736 More information about the internals of the Linux math coprocessor
1737 emulation can be found in <file:arch/x86/math-emu/README>.
1738
1739 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1740 kernel, it won't hurt.
1741
1742config MTRR
6fc108a0 1743 def_bool y
6a108a14 1744 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1745 help
506f1d07
SR
1746 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1747 the Memory Type Range Registers (MTRRs) may be used to control
1748 processor access to memory ranges. This is most useful if you have
1749 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1750 allows bus write transfers to be combined into a larger transfer
1751 before bursting over the PCI/AGP bus. This can increase performance
1752 of image write operations 2.5 times or more. Saying Y here creates a
1753 /proc/mtrr file which may be used to manipulate your processor's
1754 MTRRs. Typically the X server should use this.
1755
1756 This code has a reasonably generic interface so that similar
1757 control registers on other processors can be easily supported
1758 as well:
1759
1760 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1761 Registers (ARRs) which provide a similar functionality to MTRRs. For
1762 these, the ARRs are used to emulate the MTRRs.
1763 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1764 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1765 write-combining. All of these processors are supported by this code
1766 and it makes sense to say Y here if you have one of them.
1767
1768 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1769 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1770 can lead to all sorts of problems, so it's good to say Y here.
1771
1772 You can safely say Y even if your machine doesn't have MTRRs, you'll
1773 just add about 9 KB to your kernel.
1774
ff61f079 1775 See <file:Documentation/arch/x86/mtrr.rst> for more information.
506f1d07 1776
95ffa243 1777config MTRR_SANITIZER
2ffb3501 1778 def_bool y
95ffa243
YL
1779 prompt "MTRR cleanup support"
1780 depends on MTRR
a7f7f624 1781 help
aba3728c
TG
1782 Convert MTRR layout from continuous to discrete, so X drivers can
1783 add writeback entries.
95ffa243 1784
aba3728c 1785 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1786 The largest mtrr entry size for a continuous block can be set with
aba3728c 1787 mtrr_chunk_size.
95ffa243 1788
2ffb3501 1789 If unsure, say Y.
95ffa243
YL
1790
1791config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1792 int "MTRR cleanup enable value (0-1)"
1793 range 0 1
1794 default "0"
95ffa243 1795 depends on MTRR_SANITIZER
a7f7f624 1796 help
f5098d62 1797 Enable mtrr cleanup default value
95ffa243 1798
12031a62
YL
1799config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1800 int "MTRR cleanup spare reg num (0-7)"
1801 range 0 7
1802 default "1"
1803 depends on MTRR_SANITIZER
a7f7f624 1804 help
12031a62 1805 mtrr cleanup spare entries default, it can be changed via
aba3728c 1806 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1807
2e5d9c85 1808config X86_PAT
6fc108a0 1809 def_bool y
6a108a14 1810 prompt "x86 PAT support" if EXPERT
2a8a2719 1811 depends on MTRR
a7f7f624 1812 help
2e5d9c85 1813 Use PAT attributes to setup page level cache control.
042b78e4 1814
2e5d9c85 1815 PATs are the modern equivalents of MTRRs and are much more
1816 flexible than MTRRs.
1817
1818 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1819 spontaneous reboots) or a non-working video driver.
2e5d9c85 1820
1821 If unsure, say Y.
1822
46cf98cd
VP
1823config ARCH_USES_PG_UNCACHED
1824 def_bool y
1825 depends on X86_PAT
1826
b971880f 1827config X86_UMIP
796ebc81 1828 def_bool y
b971880f 1829 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1830 help
b971880f
BM
1831 User Mode Instruction Prevention (UMIP) is a security feature in
1832 some x86 processors. If enabled, a general protection fault is
1833 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1834 executed in user mode. These instructions unnecessarily expose
1835 information about the hardware state.
796ebc81
RN
1836
1837 The vast majority of applications do not use these instructions.
1838 For the very few that do, software emulation is provided in
1839 specific cases in protected and virtual-8086 modes. Emulated
1840 results are dummy.
aa35f896 1841
156ff4a5
PZ
1842config CC_HAS_IBT
1843 # GCC >= 9 and binutils >= 2.29
1844 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1845 # Clang/LLVM >= 14
262448f3
NC
1846 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1847 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
156ff4a5 1848 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
262448f3 1849 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
156ff4a5
PZ
1850 $(as-instr,endbr64)
1851
1852config X86_KERNEL_IBT
1853 prompt "Indirect Branch Tracking"
4fd5f70c 1854 def_bool y
03f16cd0 1855 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
f6a2c2b2
NC
1856 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1857 depends on !LD_IS_LLD || LLD_VERSION >= 140000
03f16cd0 1858 select OBJTOOL
156ff4a5
PZ
1859 help
1860 Build the kernel with support for Indirect Branch Tracking, a
1861 hardware support course-grain forward-edge Control Flow Integrity
1862 protection. It enforces that all indirect calls must land on
1863 an ENDBR instruction, as such, the compiler will instrument the
1864 code with them to make this happen.
1865
ed53a0d9 1866 In addition to building the kernel with IBT, seal all functions that
4cdfc11b 1867 are not indirect call targets, avoiding them ever becoming one.
ed53a0d9
PZ
1868
1869 This requires LTO like objtool runs and will slow down the build. It
1870 does significantly reduce the number of ENDBR instructions in the
1871 kernel image.
1872
35e97790 1873config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1874 prompt "Memory Protection Keys"
35e97790 1875 def_bool y
284244a9 1876 # Note: only available in 64-bit mode
38f3e775 1877 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1878 select ARCH_USES_HIGH_VMA_FLAGS
1879 select ARCH_HAS_PKEYS
a7f7f624 1880 help
284244a9
DH
1881 Memory Protection Keys provides a mechanism for enforcing
1882 page-based protections, but without requiring modification of the
1883 page tables when an application changes protection domains.
1884
1eecbcdc 1885 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1886
1887 If unsure, say y.
35e97790 1888
db616173
MH
1889choice
1890 prompt "TSX enable mode"
1891 depends on CPU_SUP_INTEL
1892 default X86_INTEL_TSX_MODE_OFF
1893 help
1894 Intel's TSX (Transactional Synchronization Extensions) feature
1895 allows to optimize locking protocols through lock elision which
1896 can lead to a noticeable performance boost.
1897
1898 On the other hand it has been shown that TSX can be exploited
1899 to form side channel attacks (e.g. TAA) and chances are there
1900 will be more of those attacks discovered in the future.
1901
1902 Therefore TSX is not enabled by default (aka tsx=off). An admin
1903 might override this decision by tsx=on the command line parameter.
1904 Even with TSX enabled, the kernel will attempt to enable the best
1905 possible TAA mitigation setting depending on the microcode available
1906 for the particular machine.
1907
1908 This option allows to set the default tsx mode between tsx=on, =off
1909 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1910 details.
1911
1912 Say off if not sure, auto if TSX is in use but it should be used on safe
1913 platforms or on if TSX is in use and the security aspect of tsx is not
1914 relevant.
1915
1916config X86_INTEL_TSX_MODE_OFF
1917 bool "off"
1918 help
1919 TSX is disabled if possible - equals to tsx=off command line parameter.
1920
1921config X86_INTEL_TSX_MODE_ON
1922 bool "on"
1923 help
1924 TSX is always enabled on TSX capable HW - equals the tsx=on command
1925 line parameter.
1926
1927config X86_INTEL_TSX_MODE_AUTO
1928 bool "auto"
1929 help
1930 TSX is enabled on TSX capable HW that is believed to be safe against
1931 side channel attacks- equals the tsx=auto command line parameter.
1932endchoice
1933
e7e05452
SC
1934config X86_SGX
1935 bool "Software Guard eXtensions (SGX)"
b8d1d163 1936 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
e7e05452
SC
1937 depends on CRYPTO=y
1938 depends on CRYPTO_SHA256=y
e7e05452 1939 select MMU_NOTIFIER
901ddbb9 1940 select NUMA_KEEP_MEMINFO if NUMA
40e0e784 1941 select XARRAY_MULTI
e7e05452
SC
1942 help
1943 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1944 that can be used by applications to set aside private regions of code
1945 and data, referred to as enclaves. An enclave's private memory can
1946 only be accessed by code running within the enclave. Accesses from
1947 outside the enclave, including other enclaves, are disallowed by
1948 hardware.
1949
1950 If unsure, say N.
1951
506f1d07 1952config EFI
9ba16087 1953 bool "EFI runtime service support"
5b83683f 1954 depends on ACPI
f6ce5002 1955 select UCS2_STRING
022ee6c5 1956 select EFI_RUNTIME_WRAPPERS
1ff2fc02 1957 select ARCH_USE_MEMREMAP_PROT
a7f7f624 1958 help
8f9ca475
IM
1959 This enables the kernel to use EFI runtime services that are
1960 available (such as the EFI variable services).
506f1d07 1961
8f9ca475
IM
1962 This option is only useful on systems that have EFI firmware.
1963 In addition, you should use the latest ELILO loader available
1964 at <http://elilo.sourceforge.net> in order to take advantage
1965 of EFI runtime services. However, even with this option, the
1966 resultant kernel should continue to boot on existing non-EFI
1967 platforms.
506f1d07 1968
291f3632 1969config EFI_STUB
8f24f8c2 1970 bool "EFI stub support"
c6dbd3e5 1971 depends on EFI
8f24f8c2 1972 select RELOCATABLE
a7f7f624 1973 help
8f24f8c2 1974 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
1975 by EFI firmware without the use of a bootloader.
1976
4f4cfa6c 1977 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1978
cc3fdda2
AB
1979config EFI_HANDOVER_PROTOCOL
1980 bool "EFI handover protocol (DEPRECATED)"
1981 depends on EFI_STUB
1982 default y
1983 help
1984 Select this in order to include support for the deprecated EFI
1985 handover protocol, which defines alternative entry points into the
1986 EFI stub. This is a practice that has no basis in the UEFI
1987 specification, and requires a priori knowledge on the part of the
1988 bootloader about Linux/x86 specific ways of passing the command line
1989 and initrd, and where in memory those assets may be loaded.
1990
1991 If in doubt, say Y. Even though the corresponding support is not
1992 present in upstream GRUB or other bootloaders, most distros build
1993 GRUB with numerous downstream patches applied, and may rely on the
1994 handover protocol as as result.
1995
7d453eee
MF
1996config EFI_MIXED
1997 bool "EFI mixed-mode support"
1998 depends on EFI_STUB && X86_64
a7f7f624 1999 help
758cd94a
JH
2000 Enabling this feature allows a 64-bit kernel to be booted
2001 on a 32-bit firmware, provided that your CPU supports 64-bit
2002 mode.
7d453eee 2003
758cd94a
JH
2004 Note that it is not possible to boot a mixed-mode enabled
2005 kernel via the EFI boot stub - a bootloader that supports
2006 the EFI handover protocol must be used.
7d453eee 2007
758cd94a 2008 If unsure, say N.
7d453eee 2009
4059ba65
AB
2010config EFI_FAKE_MEMMAP
2011 bool "Enable EFI fake memory map"
2012 depends on EFI
2013 help
2014 Saying Y here will enable "efi_fake_mem" boot option. By specifying
2015 this parameter, you can add arbitrary attribute to specific memory
2016 range by updating original (firmware provided) EFI memmap. This is
2017 useful for debugging of EFI memmap related feature, e.g., Address
2018 Range Mirroring feature.
2019
2020config EFI_MAX_FAKE_MEM
2021 int "maximum allowable number of ranges in efi_fake_mem boot option"
2022 depends on EFI_FAKE_MEMMAP
2023 range 1 128
2024 default 8
2025 help
2026 Maximum allowable number of ranges in efi_fake_mem boot option.
2027 Ranges can be set up to this value using comma-separated list.
2028 The default value is 8.
2029
1fff234d
AB
2030config EFI_RUNTIME_MAP
2031 bool "Export EFI runtime maps to sysfs" if EXPERT
2032 depends on EFI
2033 default KEXEC_CORE
2034 help
2035 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2036 That memory map is required by the 2nd kernel to set up EFI virtual
2037 mappings after kexec, but can also be used for debugging purposes.
2038
2039 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2040
8636a1f9 2041source "kernel/Kconfig.hz"
506f1d07 2042
6af51380
ED
2043config ARCH_SUPPORTS_KEXEC
2044 def_bool y
74ca317c 2045
6af51380
ED
2046config ARCH_SUPPORTS_KEXEC_FILE
2047 def_bool X86_64 && CRYPTO && CRYPTO_SHA256
b799a09f 2048
6af51380
ED
2049config ARCH_SELECTS_KEXEC_FILE
2050 def_bool y
74ca317c 2051 depends on KEXEC_FILE
6af51380 2052 select HAVE_IMA_KEXEC if IMA
d8eb8940 2053
6af51380
ED
2054config ARCH_HAS_KEXEC_PURGATORY
2055 def_bool KEXEC_FILE
99d5cadf 2056
6af51380
ED
2057config ARCH_SUPPORTS_KEXEC_SIG
2058 def_bool y
8e7d8381 2059
6af51380
ED
2060config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2061 def_bool y
99d5cadf 2062
6af51380
ED
2063config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2064 def_bool y
8e7d8381 2065
6af51380
ED
2066config ARCH_SUPPORTS_KEXEC_JUMP
2067 def_bool y
506f1d07 2068
6af51380
ED
2069config ARCH_SUPPORTS_CRASH_DUMP
2070 def_bool X86_64 || (X86_32 && HIGHMEM)
3ab83521 2071
506f1d07 2072config PHYSICAL_START
6a108a14 2073 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2074 default "0x1000000"
a7f7f624 2075 help
506f1d07
SR
2076 This gives the physical address where the kernel is loaded.
2077
2078 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2079 bzImage will decompress itself to above physical address and
2080 run from there. Otherwise, bzImage will run from the address where
2081 it has been loaded by the boot loader and will ignore above physical
2082 address.
2083
2084 In normal kdump cases one does not have to set/change this option
2085 as now bzImage can be compiled as a completely relocatable image
2086 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2087 address. This option is mainly useful for the folks who don't want
2088 to use a bzImage for capturing the crash dump and want to use a
2089 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2090 to be specifically compiled to run from a specific memory area
2091 (normally a reserved region) and this option comes handy.
2092
ceefccc9
PA
2093 So if you are using bzImage for capturing the crash dump,
2094 leave the value here unchanged to 0x1000000 and set
2095 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2096 for capturing the crash dump change this value to start of
2097 the reserved region. In other words, it can be set based on
2098 the "X" value as specified in the "crashkernel=YM@XM"
2099 command line boot parameter passed to the panic-ed
330d4810 2100 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2101 for more details about crash dumps.
506f1d07
SR
2102
2103 Usage of bzImage for capturing the crash dump is recommended as
2104 one does not have to build two kernels. Same kernel can be used
2105 as production kernel and capture kernel. Above option should have
2106 gone away after relocatable bzImage support is introduced. But it
2107 is present because there are users out there who continue to use
2108 vmlinux for dump capture. This option should go away down the
2109 line.
2110
2111 Don't change this unless you know what you are doing.
2112
2113config RELOCATABLE
26717808
PA
2114 bool "Build a relocatable kernel"
2115 default y
a7f7f624 2116 help
506f1d07
SR
2117 This builds a kernel image that retains relocation information
2118 so it can be loaded someplace besides the default 1MB.
2119 The relocations tend to make the kernel binary about 10% larger,
2120 but are discarded at runtime.
2121
2122 One use is for the kexec on panic case where the recovery kernel
2123 must live at a different physical address than the primary
2124 kernel.
2125
2126 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2127 it has been loaded at and the compile time physical address
8ab3820f 2128 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2129
8ab3820f 2130config RANDOMIZE_BASE
e8581e3d 2131 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2132 depends on RELOCATABLE
6807c846 2133 default y
a7f7f624 2134 help
e8581e3d
BH
2135 In support of Kernel Address Space Layout Randomization (KASLR),
2136 this randomizes the physical address at which the kernel image
2137 is decompressed and the virtual address where the kernel
2138 image is mapped, as a security feature that deters exploit
2139 attempts relying on knowledge of the location of kernel
2140 code internals.
2141
ed9f007e
KC
2142 On 64-bit, the kernel physical and virtual addresses are
2143 randomized separately. The physical address will be anywhere
2144 between 16MB and the top of physical memory (up to 64TB). The
2145 virtual address will be randomized from 16MB up to 1GB (9 bits
2146 of entropy). Note that this also reduces the memory space
2147 available to kernel modules from 1.5GB to 1GB.
2148
2149 On 32-bit, the kernel physical and virtual addresses are
2150 randomized together. They will be randomized from 16MB up to
2151 512MB (8 bits of entropy).
e8581e3d
BH
2152
2153 Entropy is generated using the RDRAND instruction if it is
2154 supported. If RDTSC is supported, its value is mixed into
2155 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2156 supported, then entropy is read from the i8254 timer. The
2157 usable entropy is limited by the kernel being built using
2158 2GB addressing, and that PHYSICAL_ALIGN must be at a
2159 minimum of 2MB. As a result, only 10 bits of entropy are
2160 theoretically possible, but the implementations are further
2161 limited due to memory layouts.
e8581e3d 2162
6807c846 2163 If unsure, say Y.
8ab3820f
KC
2164
2165# Relocation on x86 needs some additional build support
845adf72
PA
2166config X86_NEED_RELOCS
2167 def_bool y
8ab3820f 2168 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2169
506f1d07 2170config PHYSICAL_ALIGN
a0215061 2171 hex "Alignment value to which kernel should be aligned"
8ab3820f 2172 default "0x200000"
a0215061
KC
2173 range 0x2000 0x1000000 if X86_32
2174 range 0x200000 0x1000000 if X86_64
a7f7f624 2175 help
506f1d07
SR
2176 This value puts the alignment restrictions on physical address
2177 where kernel is loaded and run from. Kernel is compiled for an
2178 address which meets above alignment restriction.
2179
2180 If bootloader loads the kernel at a non-aligned address and
2181 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2182 address aligned to above value and run from there.
2183
2184 If bootloader loads the kernel at a non-aligned address and
2185 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2186 load address and decompress itself to the address it has been
2187 compiled for and run from there. The address for which kernel is
2188 compiled already meets above alignment restrictions. Hence the
2189 end result is that kernel runs from a physical address meeting
2190 above alignment restrictions.
2191
a0215061
KC
2192 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2193 this value must be a multiple of 0x200000.
2194
506f1d07
SR
2195 Don't change this unless you know what you are doing.
2196
eedb92ab
KS
2197config DYNAMIC_MEMORY_LAYOUT
2198 bool
a7f7f624 2199 help
eedb92ab
KS
2200 This option makes base addresses of vmalloc and vmemmap as well as
2201 __PAGE_OFFSET movable during boot.
2202
0483e1fa
TG
2203config RANDOMIZE_MEMORY
2204 bool "Randomize the kernel memory sections"
2205 depends on X86_64
2206 depends on RANDOMIZE_BASE
eedb92ab 2207 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2208 default RANDOMIZE_BASE
a7f7f624 2209 help
758cd94a
JH
2210 Randomizes the base virtual address of kernel memory sections
2211 (physical memory mapping, vmalloc & vmemmap). This security feature
2212 makes exploits relying on predictable memory locations less reliable.
0483e1fa 2213
758cd94a
JH
2214 The order of allocations remains unchanged. Entropy is generated in
2215 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2216 configuration have in average 30,000 different possible virtual
2217 addresses for each memory section.
0483e1fa 2218
758cd94a 2219 If unsure, say Y.
0483e1fa 2220
90397a41
TG
2221config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2222 hex "Physical memory mapping padding" if EXPERT
2223 depends on RANDOMIZE_MEMORY
2224 default "0xa" if MEMORY_HOTPLUG
2225 default "0x0"
2226 range 0x1 0x40 if MEMORY_HOTPLUG
2227 range 0x0 0x40
a7f7f624 2228 help
758cd94a
JH
2229 Define the padding in terabytes added to the existing physical
2230 memory size during kernel memory randomization. It is useful
2231 for memory hotplug support but reduces the entropy available for
2232 address randomization.
90397a41 2233
758cd94a 2234 If unsure, leave at the default value.
90397a41 2235
6449dcb0
KS
2236config ADDRESS_MASKING
2237 bool "Linear Address Masking support"
2238 depends on X86_64
2239 help
2240 Linear Address Masking (LAM) modifies the checking that is applied
2241 to 64-bit linear addresses, allowing software to use of the
2242 untranslated address bits for metadata.
2243
2244 The capability can be used for efficient address sanitizers (ASAN)
2245 implementation and for optimizations in JITs.
2246
506f1d07 2247config HOTPLUG_CPU
bebd024e 2248 def_bool y
40b31360 2249 depends on SMP
506f1d07
SR
2250
2251config COMPAT_VDSO
b0b49f26
AL
2252 def_bool n
2253 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2254 depends on COMPAT_32
a7f7f624 2255 help
b0b49f26
AL
2256 Certain buggy versions of glibc will crash if they are
2257 presented with a 32-bit vDSO that is not mapped at the address
2258 indicated in its segment table.
e84446de 2259
b0b49f26
AL
2260 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2261 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2262 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2263 the only released version with the bug, but OpenSUSE 9
2264 contains a buggy "glibc 2.3.2".
506f1d07 2265
b0b49f26
AL
2266 The symptom of the bug is that everything crashes on startup, saying:
2267 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2268
2269 Saying Y here changes the default value of the vdso32 boot
2270 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2271 This works around the glibc bug but hurts performance.
2272
2273 If unsure, say N: if you are compiling your own kernel, you
2274 are unlikely to be using a buggy version of glibc.
506f1d07 2275
3dc33bd3
KC
2276choice
2277 prompt "vsyscall table for legacy applications"
2278 depends on X86_64
625b7b7f 2279 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2280 help
2281 Legacy user code that does not know how to find the vDSO expects
2282 to be able to issue three syscalls by calling fixed addresses in
2283 kernel space. Since this location is not randomized with ASLR,
2284 it can be used to assist security vulnerability exploitation.
2285
2286 This setting can be changed at boot time via the kernel command
bf00745e
AL
2287 line parameter vsyscall=[emulate|xonly|none]. Emulate mode
2288 is deprecated and can only be enabled using the kernel command
2289 line.
3dc33bd3
KC
2290
2291 On a system with recent enough glibc (2.14 or newer) and no
2292 static binaries, you can say None without a performance penalty
2293 to improve security.
2294
bd49e16e 2295 If unsure, select "Emulate execution only".
3dc33bd3 2296
bd49e16e
AL
2297 config LEGACY_VSYSCALL_XONLY
2298 bool "Emulate execution only"
2299 help
2300 The kernel traps and emulates calls into the fixed vsyscall
2301 address mapping and does not allow reads. This
2302 configuration is recommended when userspace might use the
2303 legacy vsyscall area but support for legacy binary
2304 instrumentation of legacy code is not needed. It mitigates
2305 certain uses of the vsyscall area as an ASLR-bypassing
2306 buffer.
3dc33bd3
KC
2307
2308 config LEGACY_VSYSCALL_NONE
2309 bool "None"
2310 help
2311 There will be no vsyscall mapping at all. This will
2312 eliminate any risk of ASLR bypass due to the vsyscall
2313 fixed address mapping. Attempts to use the vsyscalls
2314 will be reported to dmesg, so that either old or
2315 malicious userspace programs can be identified.
2316
2317endchoice
2318
516cbf37
TB
2319config CMDLINE_BOOL
2320 bool "Built-in kernel command line"
a7f7f624 2321 help
516cbf37
TB
2322 Allow for specifying boot arguments to the kernel at
2323 build time. On some systems (e.g. embedded ones), it is
2324 necessary or convenient to provide some or all of the
2325 kernel boot arguments with the kernel itself (that is,
2326 to not rely on the boot loader to provide them.)
2327
2328 To compile command line arguments into the kernel,
2329 set this option to 'Y', then fill in the
69711ca1 2330 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2331
2332 Systems with fully functional boot loaders (i.e. non-embedded)
2333 should leave this option set to 'N'.
2334
2335config CMDLINE
2336 string "Built-in kernel command string"
2337 depends on CMDLINE_BOOL
2338 default ""
a7f7f624 2339 help
516cbf37
TB
2340 Enter arguments here that should be compiled into the kernel
2341 image and used at boot time. If the boot loader provides a
2342 command line at boot time, it is appended to this string to
2343 form the full kernel command line, when the system boots.
2344
2345 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2346 change this behavior.
2347
2348 In most cases, the command line (whether built-in or provided
2349 by the boot loader) should specify the device for the root
2350 file system.
2351
2352config CMDLINE_OVERRIDE
2353 bool "Built-in command line overrides boot loader arguments"
645e6466 2354 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2355 help
516cbf37
TB
2356 Set this option to 'Y' to have the kernel ignore the boot loader
2357 command line, and use ONLY the built-in command line.
2358
2359 This is used to work around broken boot loaders. This should
2360 be set to 'N' under normal conditions.
2361
a5b9e5a2
AL
2362config MODIFY_LDT_SYSCALL
2363 bool "Enable the LDT (local descriptor table)" if EXPERT
2364 default y
a7f7f624 2365 help
a5b9e5a2
AL
2366 Linux can allow user programs to install a per-process x86
2367 Local Descriptor Table (LDT) using the modify_ldt(2) system
2368 call. This is required to run 16-bit or segmented code such as
2369 DOSEMU or some Wine programs. It is also used by some very old
2370 threading libraries.
2371
2372 Enabling this feature adds a small amount of overhead to
2373 context switches and increases the low-level kernel attack
2374 surface. Disabling it removes the modify_ldt(2) system call.
2375
2376 Saying 'N' here may make sense for embedded or server kernels.
2377
3aac3ebe
TG
2378config STRICT_SIGALTSTACK_SIZE
2379 bool "Enforce strict size checking for sigaltstack"
2380 depends on DYNAMIC_SIGFRAME
2381 help
2382 For historical reasons MINSIGSTKSZ is a constant which became
2383 already too small with AVX512 support. Add a mechanism to
2384 enforce strict checking of the sigaltstack size against the
2385 real size of the FPU frame. This option enables the check
2386 by default. It can also be controlled via the kernel command
2387 line option 'strict_sas_size' independent of this config
2388 switch. Enabling it might break existing applications which
2389 allocate a too small sigaltstack but 'work' because they
2390 never get a signal delivered.
2391
2392 Say 'N' unless you want to really enforce this check.
2393
b700e7f0
SJ
2394source "kernel/livepatch/Kconfig"
2395
506f1d07
SR
2396endmenu
2397
f43b9876
PZ
2398config CC_HAS_SLS
2399 def_bool $(cc-option,-mharden-sls=all)
2400
2401config CC_HAS_RETURN_THUNK
2402 def_bool $(cc-option,-mfunction-return=thunk-extern)
2403
bea75b33
TG
2404config CC_HAS_ENTRY_PADDING
2405 def_bool $(cc-option,-fpatchable-function-entry=16,16)
2406
2407config FUNCTION_PADDING_CFI
2408 int
2409 default 59 if FUNCTION_ALIGNMENT_64B
2410 default 27 if FUNCTION_ALIGNMENT_32B
2411 default 11 if FUNCTION_ALIGNMENT_16B
2412 default 3 if FUNCTION_ALIGNMENT_8B
2413 default 0
2414
2415# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2416# except Kconfig can't do arithmetic :/
2417config FUNCTION_PADDING_BYTES
2418 int
2419 default FUNCTION_PADDING_CFI if CFI_CLANG
2420 default FUNCTION_ALIGNMENT
2421
931ab636
PZ
2422config CALL_PADDING
2423 def_bool n
2424 depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2425 select FUNCTION_ALIGNMENT_16B
2426
2427config FINEIBT
2428 def_bool y
2429 depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE
2430 select CALL_PADDING
2431
8f7c0d8b
TG
2432config HAVE_CALL_THUNKS
2433 def_bool y
bea75b33 2434 depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
8f7c0d8b
TG
2435
2436config CALL_THUNKS
2437 def_bool n
931ab636 2438 select CALL_PADDING
8f7c0d8b 2439
b341b20d
PZ
2440config PREFIX_SYMBOLS
2441 def_bool y
931ab636 2442 depends on CALL_PADDING && !CFI_CLANG
b341b20d 2443
f43b9876
PZ
2444menuconfig SPECULATION_MITIGATIONS
2445 bool "Mitigations for speculative execution vulnerabilities"
2446 default y
2447 help
2448 Say Y here to enable options which enable mitigations for
2449 speculative execution hardware vulnerabilities.
2450
2451 If you say N, all mitigations will be disabled. You really
2452 should know what you are doing to say so.
2453
2454if SPECULATION_MITIGATIONS
2455
2456config PAGE_TABLE_ISOLATION
2457 bool "Remove the kernel mapping in user mode"
2458 default y
2459 depends on (X86_64 || X86_PAE)
2460 help
2461 This feature reduces the number of hardware side channels by
2462 ensuring that the majority of kernel addresses are not mapped
2463 into userspace.
2464
ff61f079 2465 See Documentation/arch/x86/pti.rst for more details.
f43b9876
PZ
2466
2467config RETPOLINE
2468 bool "Avoid speculative indirect branches in kernel"
2469 select OBJTOOL if HAVE_OBJTOOL
2470 default y
2471 help
2472 Compile kernel with the retpoline compiler options to guard against
2473 kernel-to-user data leaks by avoiding speculative indirect
2474 branches. Requires a compiler with -mindirect-branch=thunk-extern
2475 support for full protection. The kernel may run slower.
2476
2477config RETHUNK
2478 bool "Enable return-thunks"
2479 depends on RETPOLINE && CC_HAS_RETURN_THUNK
2480 select OBJTOOL if HAVE_OBJTOOL
b648ab48 2481 default y if X86_64
f43b9876
PZ
2482 help
2483 Compile the kernel with the return-thunks compiler option to guard
2484 against kernel-to-user data leaks by avoiding return speculation.
2485 Requires a compiler with -mfunction-return=thunk-extern
2486 support for full protection. The kernel may run slower.
2487
2488config CPU_UNRET_ENTRY
2489 bool "Enable UNRET on kernel entry"
b648ab48 2490 depends on CPU_SUP_AMD && RETHUNK && X86_64
f43b9876
PZ
2491 default y
2492 help
2493 Compile the kernel with support for the retbleed=unret mitigation.
2494
80e4c1cd
TG
2495config CALL_DEPTH_TRACKING
2496 bool "Mitigate RSB underflow with call depth tracking"
2497 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2498 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2499 select CALL_THUNKS
2500 default y
2501 help
2502 Compile the kernel with call depth tracking to mitigate the Intel
2503 SKL Return-Speculation-Buffer (RSB) underflow issue. The
2504 mitigation is off by default and needs to be enabled on the
2505 kernel command line via the retbleed=stuff option. For
2506 non-affected systems the overhead of this option is marginal as
2507 the call depth tracking is using run-time generated call thunks
2508 in a compiler generated padding area and call patching. This
2509 increases text size by ~5%. For non affected systems this space
2510 is unused. On affected SKL systems this results in a significant
2511 performance gain over the IBRS mitigation.
2512
e81dc127
TG
2513config CALL_THUNKS_DEBUG
2514 bool "Enable call thunks and call depth tracking debugging"
2515 depends on CALL_DEPTH_TRACKING
2516 select FUNCTION_ALIGNMENT_32B
2517 default n
2518 help
2519 Enable call/ret counters for imbalance detection and build in
2520 a noisy dmesg about callthunks generation and call patching for
2521 trouble shooting. The debug prints need to be enabled on the
2522 kernel command line with 'debug-callthunks'.
54628de6
RD
2523 Only enable this when you are debugging call thunks as this
2524 creates a noticeable runtime overhead. If unsure say N.
80e4c1cd 2525
f43b9876
PZ
2526config CPU_IBPB_ENTRY
2527 bool "Enable IBPB on kernel entry"
b648ab48 2528 depends on CPU_SUP_AMD && X86_64
f43b9876
PZ
2529 default y
2530 help
2531 Compile the kernel with support for the retbleed=ibpb mitigation.
2532
2533config CPU_IBRS_ENTRY
2534 bool "Enable IBRS on kernel entry"
b648ab48 2535 depends on CPU_SUP_INTEL && X86_64
f43b9876
PZ
2536 default y
2537 help
2538 Compile the kernel with support for the spectre_v2=ibrs mitigation.
2539 This mitigates both spectre_v2 and retbleed at great cost to
2540 performance.
2541
2542config SLS
2543 bool "Mitigate Straight-Line-Speculation"
2544 depends on CC_HAS_SLS && X86_64
2545 select OBJTOOL if HAVE_OBJTOOL
2546 default n
2547 help
2548 Compile the kernel with straight-line-speculation options to guard
2549 against straight line speculation. The kernel image might be slightly
2550 larger.
2551
2552endif
2553
3072e413
MH
2554config ARCH_HAS_ADD_PAGES
2555 def_bool y
5c11f00b 2556 depends on ARCH_ENABLE_MEMORY_HOTPLUG
3072e413 2557
f91ef222
OS
2558config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2559 def_bool y
2560
da85f865 2561menu "Power management and ACPI options"
e279b6c1
SR
2562
2563config ARCH_HIBERNATION_HEADER
3c2362e6 2564 def_bool y
44556530 2565 depends on HIBERNATION
e279b6c1
SR
2566
2567source "kernel/power/Kconfig"
2568
2569source "drivers/acpi/Kconfig"
2570
a6b68076 2571config X86_APM_BOOT
6fc108a0 2572 def_bool y
282e5aab 2573 depends on APM
a6b68076 2574
e279b6c1
SR
2575menuconfig APM
2576 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2577 depends on X86_32 && PM_SLEEP
a7f7f624 2578 help
e279b6c1
SR
2579 APM is a BIOS specification for saving power using several different
2580 techniques. This is mostly useful for battery powered laptops with
2581 APM compliant BIOSes. If you say Y here, the system time will be
2582 reset after a RESUME operation, the /proc/apm device will provide
2583 battery status information, and user-space programs will receive
2584 notification of APM "events" (e.g. battery status change).
2585
2586 If you select "Y" here, you can disable actual use of the APM
2587 BIOS by passing the "apm=off" option to the kernel at boot time.
2588
2589 Note that the APM support is almost completely disabled for
2590 machines with more than one CPU.
2591
2592 In order to use APM, you will need supporting software. For location
151f4e2b 2593 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2594 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2595 <http://www.tldp.org/docs.html#howto>.
2596
2597 This driver does not spin down disk drives (see the hdparm(8)
2598 manpage ("man 8 hdparm") for that), and it doesn't turn off
2599 VESA-compliant "green" monitors.
2600
2601 This driver does not support the TI 4000M TravelMate and the ACER
2602 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2603 desktop machines also don't have compliant BIOSes, and this driver
2604 may cause those machines to panic during the boot phase.
2605
2606 Generally, if you don't have a battery in your machine, there isn't
2607 much point in using this driver and you should say N. If you get
2608 random kernel OOPSes or reboots that don't seem to be related to
2609 anything, try disabling/enabling this option (or disabling/enabling
2610 APM in your BIOS).
2611
2612 Some other things you should try when experiencing seemingly random,
2613 "weird" problems:
2614
2615 1) make sure that you have enough swap space and that it is
2616 enabled.
7987448f 2617 2) pass the "idle=poll" option to the kernel
e279b6c1
SR
2618 3) switch on floating point emulation in the kernel and pass
2619 the "no387" option to the kernel
2620 4) pass the "floppy=nodma" option to the kernel
2621 5) pass the "mem=4M" option to the kernel (thereby disabling
2622 all but the first 4 MB of RAM)
2623 6) make sure that the CPU is not over clocked.
2624 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2625 8) disable the cache from your BIOS settings
2626 9) install a fan for the video card or exchange video RAM
2627 10) install a better fan for the CPU
2628 11) exchange RAM chips
2629 12) exchange the motherboard.
2630
2631 To compile this driver as a module, choose M here: the
2632 module will be called apm.
2633
2634if APM
2635
2636config APM_IGNORE_USER_SUSPEND
2637 bool "Ignore USER SUSPEND"
a7f7f624 2638 help
e279b6c1
SR
2639 This option will ignore USER SUSPEND requests. On machines with a
2640 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2641 series notebooks, it is necessary to say Y because of a BIOS bug.
2642
2643config APM_DO_ENABLE
2644 bool "Enable PM at boot time"
a7f7f624 2645 help
e279b6c1
SR
2646 Enable APM features at boot time. From page 36 of the APM BIOS
2647 specification: "When disabled, the APM BIOS does not automatically
2648 power manage devices, enter the Standby State, enter the Suspend
2649 State, or take power saving steps in response to CPU Idle calls."
2650 This driver will make CPU Idle calls when Linux is idle (unless this
2651 feature is turned off -- see "Do CPU IDLE calls", below). This
2652 should always save battery power, but more complicated APM features
2653 will be dependent on your BIOS implementation. You may need to turn
2654 this option off if your computer hangs at boot time when using APM
2655 support, or if it beeps continuously instead of suspending. Turn
2656 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2657 T400CDT. This is off by default since most machines do fine without
2658 this feature.
2659
2660config APM_CPU_IDLE
dd8af076 2661 depends on CPU_IDLE
e279b6c1 2662 bool "Make CPU Idle calls when idle"
a7f7f624 2663 help
e279b6c1
SR
2664 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2665 On some machines, this can activate improved power savings, such as
2666 a slowed CPU clock rate, when the machine is idle. These idle calls
2667 are made after the idle loop has run for some length of time (e.g.,
2668 333 mS). On some machines, this will cause a hang at boot time or
2669 whenever the CPU becomes idle. (On machines with more than one CPU,
2670 this option does nothing.)
2671
2672config APM_DISPLAY_BLANK
2673 bool "Enable console blanking using APM"
a7f7f624 2674 help
e279b6c1
SR
2675 Enable console blanking using the APM. Some laptops can use this to
2676 turn off the LCD backlight when the screen blanker of the Linux
2677 virtual console blanks the screen. Note that this is only used by
2678 the virtual console screen blanker, and won't turn off the backlight
2679 when using the X Window system. This also doesn't have anything to
2680 do with your VESA-compliant power-saving monitor. Further, this
2681 option doesn't work for all laptops -- it might not turn off your
2682 backlight at all, or it might print a lot of errors to the console,
2683 especially if you are using gpm.
2684
2685config APM_ALLOW_INTS
2686 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2687 help
e279b6c1
SR
2688 Normally we disable external interrupts while we are making calls to
2689 the APM BIOS as a measure to lessen the effects of a badly behaving
2690 BIOS implementation. The BIOS should reenable interrupts if it
2691 needs to. Unfortunately, some BIOSes do not -- especially those in
2692 many of the newer IBM Thinkpads. If you experience hangs when you
2693 suspend, try setting this to Y. Otherwise, say N.
2694
e279b6c1
SR
2695endif # APM
2696
bb0a56ec 2697source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2698
2699source "drivers/cpuidle/Kconfig"
2700
27471fdb
AH
2701source "drivers/idle/Kconfig"
2702
e279b6c1
SR
2703endmenu
2704
e279b6c1
SR
2705menu "Bus options (PCI etc.)"
2706
e279b6c1
SR
2707choice
2708 prompt "PCI access mode"
efefa6f6 2709 depends on X86_32 && PCI
e279b6c1 2710 default PCI_GOANY
a7f7f624 2711 help
e279b6c1
SR
2712 On PCI systems, the BIOS can be used to detect the PCI devices and
2713 determine their configuration. However, some old PCI motherboards
2714 have BIOS bugs and may crash if this is done. Also, some embedded
2715 PCI-based systems don't have any BIOS at all. Linux can also try to
2716 detect the PCI hardware directly without using the BIOS.
2717
2718 With this option, you can specify how Linux should detect the
2719 PCI devices. If you choose "BIOS", the BIOS will be used,
2720 if you choose "Direct", the BIOS won't be used, and if you
2721 choose "MMConfig", then PCI Express MMCONFIG will be used.
2722 If you choose "Any", the kernel will try MMCONFIG, then the
2723 direct access method and falls back to the BIOS if that doesn't
2724 work. If unsure, go with the default, which is "Any".
2725
2726config PCI_GOBIOS
2727 bool "BIOS"
2728
2729config PCI_GOMMCONFIG
2730 bool "MMConfig"
2731
2732config PCI_GODIRECT
2733 bool "Direct"
2734
3ef0e1f8 2735config PCI_GOOLPC
76fb6570 2736 bool "OLPC XO-1"
3ef0e1f8
AS
2737 depends on OLPC
2738
2bdd1b03
AS
2739config PCI_GOANY
2740 bool "Any"
2741
e279b6c1
SR
2742endchoice
2743
2744config PCI_BIOS
3c2362e6 2745 def_bool y
efefa6f6 2746 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2747
2748# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2749config PCI_DIRECT
3c2362e6 2750 def_bool y
0aba496f 2751 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2752
2753config PCI_MMCONFIG
b45c9f36
JK
2754 bool "Support mmconfig PCI config space access" if X86_64
2755 default y
4590d98f 2756 depends on PCI && (ACPI || JAILHOUSE_GUEST)
b45c9f36 2757 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2758
3ef0e1f8 2759config PCI_OLPC
2bdd1b03
AS
2760 def_bool y
2761 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2762
b5401a96
AN
2763config PCI_XEN
2764 def_bool y
2765 depends on PCI && XEN
b5401a96 2766
8364e1f8
JK
2767config MMCONF_FAM10H
2768 def_bool y
2769 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2770
3f6ea84a 2771config PCI_CNB20LE_QUIRK
6a108a14 2772 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2773 depends on PCI
3f6ea84a
IS
2774 help
2775 Read the PCI windows out of the CNB20LE host bridge. This allows
2776 PCI hotplug to work on systems with the CNB20LE chipset which do
2777 not have ACPI.
2778
64a5fed6
BH
2779 There's no public spec for this chipset, and this functionality
2780 is known to be incomplete.
2781
2782 You should say N unless you know you need this.
2783
3a495511 2784config ISA_BUS
17a2a129 2785 bool "ISA bus support on modern systems" if EXPERT
3a495511 2786 help
17a2a129
WBG
2787 Expose ISA bus device drivers and options available for selection and
2788 configuration. Enable this option if your target machine has an ISA
2789 bus. ISA is an older system, displaced by PCI and newer bus
2790 architectures -- if your target machine is modern, it probably does
2791 not have an ISA bus.
3a495511
WBG
2792
2793 If unsure, say N.
2794
1c00f016 2795# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2796config ISA_DMA_API
1c00f016
DR
2797 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2798 default y
2799 help
2800 Enables ISA-style DMA support for devices requiring such controllers.
2801 If unsure, say Y.
e279b6c1 2802
51e68d05
LT
2803if X86_32
2804
e279b6c1
SR
2805config ISA
2806 bool "ISA support"
a7f7f624 2807 help
e279b6c1
SR
2808 Find out whether you have ISA slots on your motherboard. ISA is the
2809 name of a bus system, i.e. the way the CPU talks to the other stuff
2810 inside your box. Other bus systems are PCI, EISA, MicroChannel
2811 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2812 newer boards don't support it. If you have ISA, say Y, otherwise N.
2813
e279b6c1
SR
2814config SCx200
2815 tristate "NatSemi SCx200 support"
a7f7f624 2816 help
e279b6c1
SR
2817 This provides basic support for National Semiconductor's
2818 (now AMD's) Geode processors. The driver probes for the
2819 PCI-IDs of several on-chip devices, so its a good dependency
2820 for other scx200_* drivers.
2821
2822 If compiled as a module, the driver is named scx200.
2823
2824config SCx200HR_TIMER
2825 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2826 depends on SCx200
e279b6c1 2827 default y
a7f7f624 2828 help
e279b6c1
SR
2829 This driver provides a clocksource built upon the on-chip
2830 27MHz high-resolution timer. Its also a workaround for
2831 NSC Geode SC-1100's buggy TSC, which loses time when the
2832 processor goes idle (as is done by the scheduler). The
2833 other workaround is idle=poll boot option.
2834
3ef0e1f8
AS
2835config OLPC
2836 bool "One Laptop Per Child support"
54008979 2837 depends on !X86_PAE
3c554946 2838 select GPIOLIB
dc3119e7 2839 select OF
45bb1674 2840 select OF_PROMTREE
b4e51854 2841 select IRQ_DOMAIN
0c3d931b 2842 select OLPC_EC
a7f7f624 2843 help
3ef0e1f8
AS
2844 Add support for detecting the unique features of the OLPC
2845 XO hardware.
2846
a3128588
DD
2847config OLPC_XO1_PM
2848 bool "OLPC XO-1 Power Management"
fa112cf1 2849 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 2850 help
97c4cb71 2851 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2852
cfee9597
DD
2853config OLPC_XO1_RTC
2854 bool "OLPC XO-1 Real Time Clock"
2855 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 2856 help
cfee9597
DD
2857 Add support for the XO-1 real time clock, which can be used as a
2858 programmable wakeup source.
2859
7feda8e9
DD
2860config OLPC_XO1_SCI
2861 bool "OLPC XO-1 SCI extras"
92e830f2 2862 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2863 depends on INPUT=y
d8d01a63 2864 select POWER_SUPPLY
a7f7f624 2865 help
7feda8e9 2866 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2867 - EC-driven system wakeups
7feda8e9 2868 - Power button
7bc74b3d 2869 - Ebook switch
2cf2baea 2870 - Lid switch
e1040ac6
DD
2871 - AC adapter status updates
2872 - Battery status updates
7feda8e9 2873
a0f30f59
DD
2874config OLPC_XO15_SCI
2875 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2876 depends on OLPC && ACPI
2877 select POWER_SUPPLY
a7f7f624 2878 help
a0f30f59
DD
2879 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2880 - EC-driven system wakeups
2881 - AC adapter status updates
2882 - Battery status updates
bf1ebf00 2883
d4f3e350
EW
2884config ALIX
2885 bool "PCEngines ALIX System Support (LED setup)"
2886 select GPIOLIB
a7f7f624 2887 help
d4f3e350
EW
2888 This option enables system support for the PCEngines ALIX.
2889 At present this just sets up LEDs for GPIO control on
2890 ALIX2/3/6 boards. However, other system specific setup should
2891 get added here.
2892
2893 Note: You must still enable the drivers for GPIO and LED support
2894 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2895
2896 Note: You have to set alix.force=1 for boards with Award BIOS.
2897
da4e3302
PP
2898config NET5501
2899 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2900 select GPIOLIB
a7f7f624 2901 help
da4e3302
PP
2902 This option enables system support for the Soekris Engineering net5501.
2903
3197059a
PP
2904config GEOS
2905 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2906 select GPIOLIB
2907 depends on DMI
a7f7f624 2908 help
3197059a
PP
2909 This option enables system support for the Traverse Technologies GEOS.
2910
7d029125
VD
2911config TS5500
2912 bool "Technologic Systems TS-5500 platform support"
2913 depends on MELAN
2914 select CHECK_SIGNATURE
2915 select NEW_LEDS
2916 select LEDS_CLASS
a7f7f624 2917 help
7d029125
VD
2918 This option enables system support for the Technologic Systems TS-5500.
2919
bc0120fd
SR
2920endif # X86_32
2921
23ac4ae8 2922config AMD_NB
e279b6c1 2923 def_bool y
0e152cd7 2924 depends on CPU_SUP_AMD && PCI
e279b6c1 2925
e279b6c1
SR
2926endmenu
2927
1572497c 2928menu "Binary Emulations"
e279b6c1
SR
2929
2930config IA32_EMULATION
2931 bool "IA32 Emulation"
2932 depends on X86_64
39f88911 2933 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2934 select BINFMT_ELF
39f88911 2935 select COMPAT_OLD_SIGACTION
a7f7f624 2936 help
5fd92e65
L
2937 Include code to run legacy 32-bit programs under a
2938 64-bit kernel. You should likely turn this on, unless you're
2939 100% sure that you don't have any 32-bit programs left.
e279b6c1 2940
83a44a4f 2941config X86_X32_ABI
6ea30386 2942 bool "x32 ABI for 64-bit mode"
9b54050b 2943 depends on X86_64
aaeed6ec
NC
2944 # llvm-objcopy does not convert x86_64 .note.gnu.property or
2945 # compressed debug sections to x86_x32 properly:
2946 # https://github.com/ClangBuiltLinux/linux/issues/514
2947 # https://github.com/ClangBuiltLinux/linux/issues/1141
2948 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
a7f7f624 2949 help
5fd92e65
L
2950 Include code to run binaries for the x32 native 32-bit ABI
2951 for 64-bit processors. An x32 process gets access to the
2952 full 64-bit register file and wide data path while leaving
2953 pointers at 32 bits for smaller memory footprint.
2954
953fee1d
IM
2955config COMPAT_32
2956 def_bool y
2957 depends on IA32_EMULATION || X86_32
2958 select HAVE_UID16
2959 select OLD_SIGSUSPEND3
2960
e279b6c1 2961config COMPAT
3c2362e6 2962 def_bool y
83a44a4f 2963 depends on IA32_EMULATION || X86_X32_ABI
e279b6c1
SR
2964
2965config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2966 def_bool y
a9251280 2967 depends on COMPAT
ee009e4a 2968
e279b6c1
SR
2969endmenu
2970
e5beae16
KP
2971config HAVE_ATOMIC_IOMAP
2972 def_bool y
2973 depends on X86_32
2974
edf88417 2975source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
2976
2977source "arch/x86/Kconfig.assembler"