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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
daa93fab
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
341c787e
IM
20 select MODULES_USE_ELF_REL
21 select OLD_SIGACTION
2ca408d9 22 select ARCH_SPLIT_ARG64
daa93fab
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
75182022 31 select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
d94e0685
IM
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
14e56fb2 38 select EXECMEM if DYNAMIC_FTRACE
1032c0ba 39
518049d9
SRV
40config FORCE_DYNAMIC_FTRACE
41 def_bool y
42 depends on X86_32
43 depends on FUNCTION_TRACER
44 select DYNAMIC_FTRACE
45 help
758cd94a
JH
46 We keep the static function tracing (!DYNAMIC_FTRACE) around
47 in order to test the non static function tracing in the
48 generic code, as other architectures still use it. But we
49 only need to keep it around for x86_64. No need to keep it
50 for x86_32. For x86_32, force DYNAMIC_FTRACE.
d94e0685
IM
51#
52# Arch settings
53#
54# ( Note that options that are marked 'if X86_64' could in principle be
55# ported to 32-bit as well. )
56#
8d5fffb9 57config X86
3c2362e6 58 def_bool y
c763ea26
IM
59 #
60 # Note: keep this list sorted alphabetically
61 #
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IM
62 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
63 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
a02f66bb 64 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU
942fa985 65 select ARCH_32BIT_OFF_T if X86_32
2a21ad57 66 select ARCH_CLOCKSOURCE_INIT
fe42754b 67 select ARCH_CONFIGURES_CPU_MITIGATIONS
1f6d3a8f 68 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
1e866974 69 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
5c11f00b 70 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
91024b3c 71 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
cebc774f 72 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
1e866974 73 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
c763ea26 74 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
c2280be8 75 select ARCH_HAS_CACHE_LINE_SIZE
1156b441 76 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
7c7077a7 77 select ARCH_HAS_CPU_FINALIZE_INIT
8f23f5db 78 select ARCH_HAS_CPU_PASID if IOMMU_SVA
55d1ecce 79 select ARCH_HAS_CRC32
ed4bc981 80 select ARCH_HAS_CRC_T10DIF if X86_64
2792d84e 81 select ARCH_HAS_CURRENT_STACK_POINTER
fa5b6ec9 82 select ARCH_HAS_DEBUG_VIRTUAL
399145f9 83 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
21266be9 84 select ARCH_HAS_DEVMEM_IS_ALLOWED
de6c85bf 85 select ARCH_HAS_DMA_OPS if GART_IOMMU || XEN
b1a57bbf 86 select ARCH_HAS_EARLY_DEBUG if KGDB
6471b825 87 select ARCH_HAS_ELF_RANDOMIZE
72d93104 88 select ARCH_HAS_FAST_MULTIPLIER
6974f0c4 89 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 90 select ARCH_HAS_GCOV_PROFILE_ALL
bece04b5 91 select ARCH_HAS_KCOV if X86_64
b0b8a15b 92 select ARCH_HAS_KERNEL_FPU_SUPPORT
0c9c1d56 93 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 94 select ARCH_HAS_MEMBARRIER_SYNC_CORE
49f88c70 95 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
0ebeea8c 96 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
c763ea26 97 select ARCH_HAS_PMEM_API if X86_64
476e8583 98 select ARCH_HAS_PREEMPT_LAZY
17596731 99 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 100 select ARCH_HAS_PTE_SPECIAL
71ce1ab5 101 select ARCH_HAS_HW_PTE_YOUNG
eed9a328 102 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2
0aed55af 103 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
ec6347bb 104 select ARCH_HAS_COPY_MC if X86_64
d2852a22 105 select ARCH_HAS_SET_MEMORY
d253ca0c 106 select ARCH_HAS_SET_DIRECT_MAP
ad21fc4f
LA
107 select ARCH_HAS_STRICT_KERNEL_RWX
108 select ARCH_HAS_STRICT_MODULE_RWX
ac1ab12a 109 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
25c619e5 110 select ARCH_HAS_SYSCALL_WRAPPER
918327e9 111 select ARCH_HAS_UBSAN
7e01ccb4 112 select ARCH_HAS_DEBUG_WX
63703f37 113 select ARCH_HAS_ZONE_DMA_SET if EXPERT
6471b825 114 select ARCH_HAVE_NMI_SAFE_CMPXCHG
ba386777 115 select ARCH_HAVE_EXTRA_ELF_NOTES
04d5ea46 116 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
6471b825 117 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 118 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 119 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 120 select ARCH_STACKWALK
2c870e61 121 select ARCH_SUPPORTS_ACPI
6471b825 122 select ARCH_SUPPORTS_ATOMIC_RMW
5d6ad668 123 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
d283d422 124 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64
6471b825 125 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
14df3267 126 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096
3c516f89
ST
127 select ARCH_SUPPORTS_CFI_CLANG if X86_64
128 select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG
583bfd48
NC
129 select ARCH_SUPPORTS_LTO_CLANG
130 select ARCH_SUPPORTS_LTO_CLANG_THIN
d2d6422f 131 select ARCH_SUPPORTS_RT
315ad878 132 select ARCH_SUPPORTS_AUTOFDO_CLANG
d5dc9583 133 select ARCH_SUPPORTS_PROPELLER_CLANG if X86_64
6471b825 134 select ARCH_USE_BUILTIN_BSWAP
a432b7c0 135 select ARCH_USE_CMPXCHG_LOCKREF if X86_CMPXCHG64
dce44566 136 select ARCH_USE_MEMTEST
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IM
137 select ARCH_USE_QUEUED_RWLOCKS
138 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 139 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 140 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 141 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 142 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
51c2ee6d 143 select ARCH_WANTS_NO_INSTR
07431506 144 select ARCH_WANT_GENERAL_HUGETLB
3876d4a3 145 select ARCH_WANT_HUGE_PMD_SHARE
59612b24 146 select ARCH_WANT_LD_ORPHAN_WARN
0b6f1582
AK
147 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64
148 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64
38d8b4e6 149 select ARCH_WANTS_THP_SWAP if X86_64
b5f06f64 150 select ARCH_HAS_PARANOID_L1D_FLUSH
10916706 151 select BUILDTIME_TABLE_SORT
6471b825 152 select CLKEVT_I8253
6471b825 153 select CLOCKSOURCE_WATCHDOG
7cf8f44a
AP
154 # Word-size accesses may read uninitialized data past the trailing \0
155 # in strings and cause false KMSAN reports.
156 select DCACHE_WORD_ACCESS if !KMSAN
3aac3ebe 157 select DYNAMIC_SIGFRAME
45471cd9
LT
158 select EDAC_ATOMIC_SCRUB
159 select EDAC_SUPPORT
6471b825 160 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
cb81deef 161 select GENERIC_CLOCKEVENTS_BROADCAST_IDLE if GENERIC_CLOCKEVENTS_BROADCAST
6471b825
IM
162 select GENERIC_CLOCKEVENTS_MIN_ADJUST
163 select GENERIC_CMOS_UPDATE
164 select GENERIC_CPU_AUTOPROBE
5b95f94c 165 select GENERIC_CPU_DEVICES
61dc0f55 166 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 167 select GENERIC_EARLY_IOREMAP
27d6b4d1 168 select GENERIC_ENTRY
6471b825 169 select GENERIC_IOMAP
c7d6c9dd 170 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 171 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 172 select GENERIC_IRQ_MIGRATION if SMP
6471b825 173 select GENERIC_IRQ_PROBE
c201c917 174 select GENERIC_IRQ_RESERVATION_MODE
6471b825
IM
175 select GENERIC_IRQ_SHOW
176 select GENERIC_PENDING_IRQ if SMP
2ae27137 177 select GENERIC_PTDUMP
6471b825 178 select GENERIC_SMP_IDLE_THREAD
6471b825 179 select GENERIC_TIME_VSYSCALL
7ac87074 180 select GENERIC_GETTIMEOFDAY
550a77a7 181 select GENERIC_VDSO_TIME_NS
7e90ffb7 182 select GENERIC_VDSO_OVERFLOW_PROTECT
6ca297d4 183 select GUP_GET_PXX_LOW_HIGH if X86_PAE
17e5888e 184 select HARDIRQS_SW_RESEND
7edaeb68 185 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
fcbfe812 186 select HAS_IOPORT
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IM
187 select HAVE_ACPI_APEI if ACPI
188 select HAVE_ACPI_APEI_NMI if ACPI
2a19be61 189 select HAVE_ALIGNED_STRUCT_PAGE
6471b825
IM
190 select HAVE_ARCH_AUDITSYSCALL
191 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
eed1fcee 192 select HAVE_ARCH_HUGE_VMALLOC if X86_64
6471b825 193 select HAVE_ARCH_JUMP_LABEL
b34006c4 194 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 195 select HAVE_ARCH_KASAN if X86_64
0609ae01 196 select HAVE_ARCH_KASAN_VMALLOC if X86_64
1dc0da6e 197 select HAVE_ARCH_KFENCE
4ca8cc8d 198 select HAVE_ARCH_KMSAN if X86_64
6471b825 199 select HAVE_ARCH_KGDB
9e08f57d
DC
200 select HAVE_ARCH_MMAP_RND_BITS if MMU
201 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 202 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 203 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 204 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 205 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 206 select HAVE_ARCH_STACKLEAK
6471b825
IM
207 select HAVE_ARCH_TRACEHOOK
208 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 209 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 210 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
7677f7fd 211 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD
e37e43a4 212 select HAVE_ARCH_VMAP_STACK if X86_64
fe950f60 213 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
c763ea26 214 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 215 select HAVE_ASM_MODVERSIONS
6471b825
IM
216 select HAVE_CMPXCHG_DOUBLE
217 select HAVE_CMPXCHG_LOCAL
24a9c541
FW
218 select HAVE_CONTEXT_TRACKING_USER if X86_64
219 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER
cf4db259 220 select HAVE_C_RECORDMCOUNT
03f16cd0 221 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL
280981d6 222 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT
4ed308c4 223 select HAVE_BUILDTIME_MCOUNT_SORT
6471b825 224 select HAVE_DEBUG_KMEMLEAK
6471b825 225 select HAVE_DMA_CONTIGUOUS
677aa9f7 226 select HAVE_DYNAMIC_FTRACE
06aeaaea 227 select HAVE_DYNAMIC_FTRACE_WITH_REGS
02a474ca 228 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64
762abbc0 229 select HAVE_FTRACE_REGS_HAVING_PT_REGS if X86_64
562955fe 230 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
c316eb44 231 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64
503e4510 232 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64
03f5781b 233 select HAVE_EBPF_JIT
58340a07 234 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 235 select HAVE_EISA
5f56a5df 236 select HAVE_EXIT_THREAD
25176ad0 237 select HAVE_GUP_FAST
644e0e8d 238 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
a762e926 239 select HAVE_FTRACE_GRAPH_FUNC if HAVE_FUNCTION_GRAPH_TRACER
6471b825 240 select HAVE_FTRACE_MCOUNT_RECORD
a3ed4157 241 select HAVE_FUNCTION_GRAPH_FREGS if HAVE_FUNCTION_GRAPH_TRACER
4a30e4c9 242 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE)
6471b825 243 select HAVE_FUNCTION_TRACER
6b90bd4b 244 select HAVE_GCC_PLUGINS
6471b825 245 select HAVE_HW_BREAKPOINT
6471b825 246 select HAVE_IOREMAP_PROT
624db9ea 247 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
6471b825 248 select HAVE_IRQ_TIME_ACCOUNTING
4ab7674f 249 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL
2e9f3bdd 250 select HAVE_KERNEL_BZIP2
6471b825
IM
251 select HAVE_KERNEL_GZIP
252 select HAVE_KERNEL_LZ4
2e9f3bdd 253 select HAVE_KERNEL_LZMA
13510997 254 select HAVE_KERNEL_LZO
6471b825 255 select HAVE_KERNEL_XZ
fb46d057 256 select HAVE_KERNEL_ZSTD
6471b825
IM
257 select HAVE_KPROBES
258 select HAVE_KPROBES_ON_FTRACE
540adea3 259 select HAVE_FUNCTION_ERROR_INJECTION
6471b825 260 select HAVE_KRETPROBES
f3a112c0 261 select HAVE_RETHOOK
6471b825 262 select HAVE_LIVEPATCH if X86_64
0102752e 263 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 264 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 265 select HAVE_MOVE_PMD
be37c98d 266 select HAVE_MOVE_PUD
22102f45 267 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL
42a0bb3f 268 select HAVE_NMI
489e355b 269 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL
03f16cd0 270 select HAVE_OBJTOOL if X86_64
6471b825 271 select HAVE_OPTPROBES
5394f1e9 272 select HAVE_PAGE_SIZE_4KB
6471b825
IM
273 select HAVE_PCSPKR_PLATFORM
274 select HAVE_PERF_EVENTS
c01d4323 275 select HAVE_PERF_EVENTS_NMI
92e5aae4 276 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 277 select HAVE_PCI
c5e63197 278 select HAVE_PERF_REGS
c5ebcedb 279 select HAVE_PERF_USER_STACK_DUMP
03f16cd0 280 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
1e9fdf21 281 select MMU_GATHER_MERGE_VMAS
00998085 282 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 283 select HAVE_REGS_AND_STACK_ACCESS_API
03f16cd0 284 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION
3c88ee19 285 select HAVE_FUNCTION_ARG_ACCESS_API
7ecd19cf 286 select HAVE_SETUP_PER_CPU_AREA
cd1a41ce 287 select HAVE_SOFTIRQ_ON_OWN_STACK
d148eac0 288 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
03f16cd0 289 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL
e6d6c071 290 select HAVE_STATIC_CALL
03f16cd0 291 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL
99cf983c 292 select HAVE_PREEMPT_DYNAMIC_CALL
d6761b8f 293 select HAVE_RSEQ
09498135 294 select HAVE_RUST if X86_64
6471b825 295 select HAVE_SYSCALL_TRACEPOINTS
5f3da8c0 296 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL
6471b825 297 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 298 select HAVE_USER_RETURN_NOTIFIER
7ac87074 299 select HAVE_GENERIC_VDSO
33385150 300 select VDSO_GETRANDOM if X86_64
0c7ffa32 301 select HOTPLUG_PARALLEL if SMP && X86_64
05736e4a 302 select HOTPLUG_SMT if SMP
0c7ffa32 303 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32
c0185808 304 select IRQ_FORCED_THREADING
c2508ec5 305 select LOCK_MM_AND_FIND_VMA
7ecd19cf
KW
306 select NEED_PER_CPU_EMBED_FIRST_CHUNK
307 select NEED_PER_CPU_PAGE_FIRST_CHUNK
86596f0a 308 select NEED_SG_DMA_LENGTH
87482708 309 select NUMA_MEMBLKS if NUMA
2eac9c2d 310 select PCI_DOMAINS if PCI
625210cf 311 select PCI_LOCKLESS_CONFIG if PCI
6471b825 312 select PERF_EVENTS
3195ef59 313 select RTC_LIB
d6faca40 314 select RTC_MC146818_LIB
6471b825 315 select SPARSE_IRQ
6471b825 316 select SYSCTL_EXCEPTION_TRACE
15f4eae7 317 select THREAD_INFO_IN_TASK
4aae683f 318 select TRACE_IRQFLAGS_SUPPORT
4510bffb 319 select TRACE_IRQFLAGS_NMI_SUPPORT
6471b825 320 select USER_STACKTRACE_SUPPORT
3b02a051 321 select HAVE_ARCH_KCSAN if X86_64
0c608dad 322 select PROC_PID_ARCH_STATUS if PROC_FS
50468e43 323 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX
d49a0626
PZ
324 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16
325 select FUNCTION_ALIGNMENT_4B
9e2b4be3 326 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
ceea991a 327 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
4817f70c 328 select ARCH_SUPPORTS_PT_RECLAIM if X86_64
7d8330a5 329
ba7e4d13 330config INSTRUCTION_DECODER
3120e25e
JB
331 def_bool y
332 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 333
51b26ada
LT
334config OUTPUT_FORMAT
335 string
336 default "elf32-i386" if X86_32
337 default "elf64-x86-64" if X86_64
338
8d5fffb9 339config LOCKDEP_SUPPORT
3c2362e6 340 def_bool y
8d5fffb9
SR
341
342config STACKTRACE_SUPPORT
3c2362e6 343 def_bool y
8d5fffb9 344
8d5fffb9 345config MMU
3c2362e6 346 def_bool y
8d5fffb9 347
9e08f57d
DC
348config ARCH_MMAP_RND_BITS_MIN
349 default 28 if 64BIT
350 default 8
351
352config ARCH_MMAP_RND_BITS_MAX
353 default 32 if 64BIT
354 default 16
355
356config ARCH_MMAP_RND_COMPAT_BITS_MIN
357 default 8
358
359config ARCH_MMAP_RND_COMPAT_BITS_MAX
360 default 16
361
8d5fffb9
SR
362config SBUS
363 bool
364
365config GENERIC_ISA_DMA
3120e25e
JB
366 def_bool y
367 depends on ISA_DMA_API
8d5fffb9 368
d911c67e
AP
369config GENERIC_CSUM
370 bool
371 default y if KMSAN || KASAN
372
8d5fffb9 373config GENERIC_BUG
3c2362e6 374 def_bool y
8d5fffb9 375 depends on BUG
b93a531e
JB
376 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
377
378config GENERIC_BUG_RELATIVE_POINTERS
379 bool
8d5fffb9 380
8d5fffb9 381config ARCH_MAY_HAVE_PC_FDC
3120e25e
JB
382 def_bool y
383 depends on ISA_DMA_API
8d5fffb9 384
1032c0ba
SR
385config GENERIC_CALIBRATE_DELAY
386 def_bool y
387
9a0b8415 388config ARCH_HAS_CPU_RELAX
389 def_bool y
390
801e4062
JB
391config ARCH_HIBERNATION_POSSIBLE
392 def_bool y
801e4062 393
f4cb5700
JB
394config ARCH_SUSPEND_POSSIBLE
395 def_bool y
f4cb5700 396
8d5fffb9 397config AUDIT_ARCH
e0fd24a3 398 def_bool y if X86_64
8d5fffb9 399
d6f2d75a
AR
400config KASAN_SHADOW_OFFSET
401 hex
402 depends on KASAN
403 default 0xdffffc0000000000
404
69575d38
SW
405config HAVE_INTEL_TXT
406 def_bool y
6ea30386 407 depends on INTEL_IOMMU && ACPI
69575d38 408
6b0c3d44
SR
409config X86_64_SMP
410 def_bool y
411 depends on X86_64 && SMP
412
2b144498
SD
413config ARCH_SUPPORTS_UPROBES
414 def_bool y
415
d20642f0
RH
416config FIX_EARLYCON_MEM
417 def_bool y
418
94d49eb3
KS
419config DYNAMIC_PHYSICAL_MASK
420 bool
421
98233368
KS
422config PGTABLE_LEVELS
423 int
77ef56e4 424 default 5 if X86_5LEVEL
98233368
KS
425 default 4 if X86_64
426 default 3 if X86_PAE
427 default 2
428
2a61f474
MY
429config CC_HAS_SANE_STACKPROTECTOR
430 bool
1b866781
NC
431 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
432 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
2a61f474 433 help
758cd94a
JH
434 We have to make sure stack protector is unconditionally disabled if
435 the compiler produces broken code or if it does not let us control
436 the segment on 32-bit kernels.
2a61f474 437
506f1d07
SR
438menu "Processor type and features"
439
506f1d07
SR
440config SMP
441 bool "Symmetric multi-processing support"
a7f7f624 442 help
506f1d07 443 This enables support for systems with more than one CPU. If you have
4a474157
RG
444 a system with only one CPU, say N. If you have a system with more
445 than one CPU, say Y.
506f1d07 446
4a474157 447 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
448 machines, but will use only one CPU of a multiprocessor machine. If
449 you say Y here, the kernel will run on many, but not all,
4a474157 450 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
451 will run faster if you say N here.
452
453 Note that if you say Y here and choose architecture "586" or
454 "Pentium" under "Processor family", the kernel will not work on 486
455 architectures. Similarly, multiprocessor kernels for the "PPro"
456 architecture may not work on all Pentium based boards.
457
458 People using multiprocessor machines who say Y here should also say
459 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
460 Management" code will be disabled if you say Y here.
461
ff61f079 462 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
4f4cfa6c 463 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
464 <http://www.tldp.org/docs.html#howto>.
465
466 If you don't know what to do here, say N.
467
06cd9a7d
YL
468config X86_X2APIC
469 bool "Support x2apic"
19e3d60d 470 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 471 help
06cd9a7d
YL
472 This enables x2apic support on CPUs that have this feature.
473
474 This allows 32-bit apic IDs (so it can support very large systems),
475 and accesses the local apic via MSRs not via mmio.
476
b8d1d163
DS
477 Some Intel systems circa 2022 and later are locked into x2APIC mode
478 and can not fall back to the legacy APIC modes if SGX or TDX are
e3998434
MJ
479 enabled in the BIOS. They will boot with very reduced functionality
480 without enabling this option.
b8d1d163 481
06cd9a7d
YL
482 If you don't know what to do here, say N.
483
7fec07fd
JP
484config X86_POSTED_MSI
485 bool "Enable MSI and MSI-x delivery by posted interrupts"
486 depends on X86_64 && IRQ_REMAP
487 help
488 This enables MSIs that are under interrupt remapping to be delivered as
489 posted interrupts to the host kernel. Interrupt throughput can
490 potentially be improved by coalescing CPU notifications during high
491 frequency bursts.
b8d1d163 492
06cd9a7d
YL
493 If you don't know what to do here, say N.
494
6695c85b 495config X86_MPPARSE
4590d98f 496 bool "Enable MPS table" if ACPI
7a527688 497 default y
5ab74722 498 depends on X86_LOCAL_APIC
a7f7f624 499 help
6695c85b
YL
500 For old smp systems that do not have proper acpi support. Newer systems
501 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 502
e6d42931
JW
503config X86_CPU_RESCTRL
504 bool "x86 CPU resource control support"
6fe07ce3 505 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 506 select KERNFS
e79f15a4 507 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 508 help
e6d42931 509 Enable x86 CPU resource control support.
6fe07ce3
BM
510
511 Provide support for the allocation and monitoring of system resources
512 usage by the CPU.
513
514 Intel calls this Intel Resource Director Technology
515 (Intel(R) RDT). More information about RDT can be found in the
516 Intel x86 Architecture Software Developer Manual.
517
518 AMD calls this AMD Platform Quality of Service (AMD QoS).
519 More information about AMD QoS can be found in the AMD64 Technology
520 Platform Quality of Service Extensions manual.
78e99b4a
FY
521
522 Say N if unsure.
523
2cce9591
PAI
524config X86_FRED
525 bool "Flexible Return and Event Delivery"
526 depends on X86_64
527 help
528 When enabled, try to use Flexible Return and Event Delivery
529 instead of the legacy SYSCALL/SYSENTER/IDT architecture for
530 ring transitions and exception/interrupt handling if the
3c41786c 531 system supports it.
2cce9591 532
a0d0bb4d
RD
533config X86_BIGSMP
534 bool "Support for big SMP systems with more than 8 CPUs"
71d99ea4 535 depends on SMP && X86_32
a7f7f624 536 help
e133f6ea 537 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 538
c5c606d9
RT
539config X86_EXTENDED_PLATFORM
540 bool "Support for extended (non-PC) x86 platforms"
541 default y
a7f7f624 542 help
06ac8346
IM
543 If you disable this option then the kernel will only support
544 standard PC platforms. (which covers the vast majority of
545 systems out there.)
546
8425091f 547 If you enable this option then you'll be able to select support
71d99ea4
MY
548 for the following non-PC x86 platforms, depending on the value of
549 CONFIG_64BIT.
550
551 32-bit platforms (CONFIG_64BIT=n):
cb7b8023 552 Goldfish (Android emulator)
8425091f 553 AMD Elan
8425091f
RT
554 RDC R-321x SoC
555 SGI 320/540 (Visual Workstation)
83125a3a 556 STA2X11-based (e.g. Northville)
3f4110a4 557 Moorestown MID devices
06ac8346 558
71d99ea4 559 64-bit platforms (CONFIG_64BIT=y):
44b111b5 560 Numascale NumaChip
8425091f
RT
561 ScaleMP vSMP
562 SGI Ultraviolet
563
564 If you have one of these systems, or if you want to build a
565 generic distribution kernel, say Y here - otherwise say N.
71d99ea4 566
c5c606d9
RT
567# This is an alphabetically sorted list of 64 bit extended platforms
568# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
569config X86_NUMACHIP
570 bool "Numascale NumaChip"
571 depends on X86_64
572 depends on X86_EXTENDED_PLATFORM
573 depends on NUMA
574 depends on SMP
575 depends on X86_X2APIC
f9726bfd 576 depends on PCI_MMCONFIG
a7f7f624 577 help
44b111b5
SP
578 Adds support for Numascale NumaChip large-SMP systems. Needed to
579 enable more than ~168 cores.
580 If you don't have one of these, you should say N here.
506f1d07 581
c5c606d9
RT
582config X86_VSMP
583 bool "ScaleMP vSMP"
6276a074 584 select HYPERVISOR_GUEST
c5c606d9
RT
585 select PARAVIRT
586 depends on X86_64 && PCI
587 depends on X86_EXTENDED_PLATFORM
ead91d4b 588 depends on SMP
a7f7f624 589 help
c5c606d9
RT
590 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
591 supposed to run on these EM64T-based machines. Only choose this option
592 if you have one of these machines.
5e3a77e9 593
03b48632
NP
594config X86_UV
595 bool "SGI Ultraviolet"
596 depends on X86_64
c5c606d9 597 depends on X86_EXTENDED_PLATFORM
54c28d29 598 depends on NUMA
1ecb4ae5 599 depends on EFI
c2209ea5 600 depends on KEXEC_CORE
9d6c26e7 601 depends on X86_X2APIC
1222e564 602 depends on PCI
a7f7f624 603 help
03b48632
NP
604 This option is needed in order to support SGI Ultraviolet systems.
605 If you don't have one of these, you should say N here.
606
c5c606d9
RT
607# Following is an alphabetically sorted list of 32 bit extended platforms
608# Please maintain the alphabetic order if and when there are additions
506f1d07 609
ddd70cf9 610config X86_GOLDFISH
b03b016f
KK
611 bool "Goldfish (Virtual Platform)"
612 depends on X86_EXTENDED_PLATFORM
a7f7f624 613 help
758cd94a
JH
614 Enable support for the Goldfish virtual platform used primarily
615 for Android development. Unless you are building for the Android
616 Goldfish emulator say N here.
ddd70cf9 617
c751e17b
TG
618config X86_INTEL_CE
619 bool "CE4100 TV platform"
620 depends on PCI
621 depends on PCI_GODIRECT
6084a6e2 622 depends on X86_IO_APIC
c751e17b
TG
623 depends on X86_32
624 depends on X86_EXTENDED_PLATFORM
37bc9f50 625 select X86_REBOOTFIXUPS
da6b737b
SAS
626 select OF
627 select OF_EARLY_FLATTREE
a7f7f624 628 help
c751e17b
TG
629 Select for the Intel CE media processor (CE4100) SOC.
630 This option compiles in support for the CE4100 SOC for settop
631 boxes and media devices.
632
4cb9b00f 633config X86_INTEL_MID
43605ef1 634 bool "Intel MID platform support"
43605ef1 635 depends on X86_EXTENDED_PLATFORM
edc6bc78 636 depends on X86_PLATFORM_DEVICES
1ea7c673 637 depends on PCI
3fda5bb4 638 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 639 depends on X86_IO_APIC
4cb9b00f 640 select I2C
7c9c3a1e 641 select DW_APB_TIMER
54b34aa0 642 select INTEL_SCU_PCI
a7f7f624 643 help
4cb9b00f
DC
644 Select to build a kernel capable of supporting Intel MID (Mobile
645 Internet Device) platform systems which do not have the PCI legacy
646 interfaces. If you are building for a PC class system say N here.
1ea7c673 647
4cb9b00f
DC
648 Intel MID platforms are based on an Intel processor and chipset which
649 consume less power than most of the x86 derivatives.
43605ef1 650
8bbc2a13
BD
651config X86_INTEL_QUARK
652 bool "Intel Quark platform support"
653 depends on X86_32
654 depends on X86_EXTENDED_PLATFORM
655 depends on X86_PLATFORM_DEVICES
656 depends on X86_TSC
657 depends on PCI
658 depends on PCI_GOANY
659 depends on X86_IO_APIC
660 select IOSF_MBI
661 select INTEL_IMR
9ab6eb51 662 select COMMON_CLK
a7f7f624 663 help
8bbc2a13
BD
664 Select to include support for Quark X1000 SoC.
665 Say Y here if you have a Quark based system such as the Arduino
666 compatible Intel Galileo.
667
3d48aab1
MW
668config X86_INTEL_LPSS
669 bool "Intel Low Power Subsystem Support"
5962dd22 670 depends on X86 && ACPI && PCI
3d48aab1 671 select COMMON_CLK
0f531431 672 select PINCTRL
eebb3e8d 673 select IOSF_MBI
a7f7f624 674 help
3d48aab1
MW
675 Select to build support for Intel Low Power Subsystem such as
676 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
677 things like clock tree (common clock framework) and pincontrol
678 which are needed by the LPSS peripheral drivers.
3d48aab1 679
92082a88
KX
680config X86_AMD_PLATFORM_DEVICE
681 bool "AMD ACPI2Platform devices support"
682 depends on ACPI
683 select COMMON_CLK
684 select PINCTRL
a7f7f624 685 help
92082a88
KX
686 Select to interpret AMD specific ACPI device to platform device
687 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
688 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
689 implemented under PINCTRL subsystem.
690
ced3ce76
DB
691config IOSF_MBI
692 tristate "Intel SoC IOSF Sideband support for SoC platforms"
693 depends on PCI
a7f7f624 694 help
ced3ce76
DB
695 This option enables sideband register access support for Intel SoC
696 platforms. On these platforms the IOSF sideband is used in lieu of
697 MSR's for some register accesses, mostly but not limited to thermal
698 and power. Drivers may query the availability of this device to
699 determine if they need the sideband in order to work on these
700 platforms. The sideband is available on the following SoC products.
701 This list is not meant to be exclusive.
702 - BayTrail
703 - Braswell
704 - Quark
705
706 You should say Y if you are running a kernel on one of these SoC's.
707
ed2226bd
DB
708config IOSF_MBI_DEBUG
709 bool "Enable IOSF sideband access through debugfs"
710 depends on IOSF_MBI && DEBUG_FS
a7f7f624 711 help
ed2226bd
DB
712 Select this option to expose the IOSF sideband access registers (MCR,
713 MDR, MCRX) through debugfs to write and read register information from
714 different units on the SoC. This is most useful for obtaining device
715 state information for debug and analysis. As this is a general access
716 mechanism, users of this option would have specific knowledge of the
717 device they want to access.
718
719 If you don't require the option or are in doubt, say N.
720
c5c606d9
RT
721config X86_RDC321X
722 bool "RDC R-321x SoC"
506f1d07 723 depends on X86_32
c5c606d9
RT
724 depends on X86_EXTENDED_PLATFORM
725 select M486
726 select X86_REBOOTFIXUPS
a7f7f624 727 help
c5c606d9
RT
728 This option is needed for RDC R-321x system-on-chip, also known
729 as R-8610-(G).
730 If you don't have one of these chips, you should say N here.
731
e0c7ae37 732config X86_32_NON_STANDARD
9c398017
IM
733 bool "Support non-standard 32-bit SMP architectures"
734 depends on X86_32 && SMP
c5c606d9 735 depends on X86_EXTENDED_PLATFORM
a7f7f624 736 help
b5660ba7
PA
737 This option compiles in the bigsmp and STA2X11 default
738 subarchitectures. It is intended for a generic binary
739 kernel. If you select them all, kernel will probe it one by
740 one and will fallback to default.
d49c4288 741
c5c606d9 742# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 743
d949f36f 744config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 745 def_bool y
d949f36f
LT
746 # MCE code calls memory_failure():
747 depends on X86_MCE
748 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
749 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
750 depends on X86_64 || !SPARSEMEM
751 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 752
83125a3a
AR
753config STA2X11
754 bool "STA2X11 Companion Chip Support"
755 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
756 select SWIOTLB
757 select MFD_STA2X11
0145071b 758 select GPIOLIB
a7f7f624 759 help
83125a3a
AR
760 This adds support for boards based on the STA2X11 IO-Hub,
761 a.k.a. "ConneXt". The chip is used in place of the standard
762 PC chipset, so all "standard" peripherals are missing. If this
763 option is selected the kernel will still be able to boot on
764 standard PC machines.
765
82148d1d
S
766config X86_32_IRIS
767 tristate "Eurobraille/Iris poweroff module"
768 depends on X86_32
a7f7f624 769 help
82148d1d
S
770 The Iris machines from EuroBraille do not have APM or ACPI support
771 to shut themselves down properly. A special I/O sequence is
772 needed to do so, which is what this module does at
773 kernel shutdown.
774
775 This is only for Iris machines from EuroBraille.
776
777 If unused, say N.
778
ae1e9130 779config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
780 def_bool y
781 prompt "Single-depth WCHAN output"
a87d0914 782 depends on X86
a7f7f624 783 help
506f1d07
SR
784 Calculate simpler /proc/<PID>/wchan values. If this option
785 is disabled then wchan values will recurse back to the
786 caller function. This provides more accurate wchan values,
787 at the expense of slightly more scheduling overhead.
788
789 If in doubt, say "Y".
790
6276a074
BP
791menuconfig HYPERVISOR_GUEST
792 bool "Linux guest support"
a7f7f624 793 help
6276a074
BP
794 Say Y here to enable options for running Linux under various hyper-
795 visors. This option enables basic hypervisor detection and platform
796 setup.
506f1d07 797
6276a074
BP
798 If you say N, all options in this submenu will be skipped and
799 disabled, and Linux guest support won't be built in.
506f1d07 800
6276a074 801if HYPERVISOR_GUEST
506f1d07 802
e61bd94a
EPH
803config PARAVIRT
804 bool "Enable paravirtualization code"
a0e2bf7c 805 depends on HAVE_STATIC_CALL
a7f7f624 806 help
e61bd94a
EPH
807 This changes the kernel so it can modify itself when it is run
808 under a hypervisor, potentially improving performance significantly
809 over full virtualization. However, when run without a hypervisor
810 the kernel is theoretically slower and slightly larger.
811
c00a280a
JG
812config PARAVIRT_XXL
813 bool
814
6276a074
BP
815config PARAVIRT_DEBUG
816 bool "paravirt-ops debugging"
817 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 818 help
6276a074
BP
819 Enable to debug paravirt_ops internals. Specifically, BUG if
820 a paravirt_op is missing when it is called.
821
b4ecc126
JF
822config PARAVIRT_SPINLOCKS
823 bool "Paravirtualization layer for spinlocks"
6ea30386 824 depends on PARAVIRT && SMP
a7f7f624 825 help
b4ecc126
JF
826 Paravirtualized spinlocks allow a pvops backend to replace the
827 spinlock implementation with something virtualization-friendly
828 (for example, block the virtual CPU rather than spinning).
829
4c4e4f61
R
830 It has a minimal impact on native kernels and gives a nice performance
831 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 832
4c4e4f61 833 If you are unsure how to answer this question, answer Y.
b4ecc126 834
ecca2502
ZY
835config X86_HV_CALLBACK_VECTOR
836 def_bool n
837
6276a074 838source "arch/x86/xen/Kconfig"
7af192c9 839
6276a074
BP
840config KVM_GUEST
841 bool "KVM Guest support (including kvmclock)"
842 depends on PARAVIRT
843 select PARAVIRT_CLOCK
a1c4423b 844 select ARCH_CPUIDLE_HALTPOLL
b1d40575 845 select X86_HV_CALLBACK_VECTOR
6276a074 846 default y
a7f7f624 847 help
6276a074
BP
848 This option enables various optimizations for running under the KVM
849 hypervisor. It includes a paravirtualized clock, so that instead
850 of relying on a PIT (or probably other) emulation by the
851 underlying device model, the host provides the guest with
852 timing infrastructure such as time of day, and system time
506f1d07 853
a1c4423b 854config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
855 def_bool n
856 prompt "Disable host haltpoll when loading haltpoll driver"
857 help
a1c4423b
MT
858 If virtualized under KVM, disable host haltpoll.
859
7733607f
MW
860config PVH
861 bool "Support for running PVH guests"
a7f7f624 862 help
7733607f
MW
863 This option enables the PVH entry point for guest virtual machines
864 as specified in the x86/HVM direct boot ABI.
865
6276a074
BP
866config PARAVIRT_TIME_ACCOUNTING
867 bool "Paravirtual steal time accounting"
868 depends on PARAVIRT
a7f7f624 869 help
6276a074
BP
870 Select this option to enable fine granularity task steal time
871 accounting. Time spent executing other tasks in parallel with
872 the current vCPU is discounted from the vCPU power. To account for
873 that, there can be a small performance impact.
874
875 If in doubt, say N here.
876
877config PARAVIRT_CLOCK
878 bool
97349135 879
4a362601
JK
880config JAILHOUSE_GUEST
881 bool "Jailhouse non-root cell support"
abde587b 882 depends on X86_64 && PCI
87e65d05 883 select X86_PM_TIMER
a7f7f624 884 help
4a362601
JK
885 This option allows to run Linux as guest in a Jailhouse non-root
886 cell. You can leave this option disabled if you only want to start
887 Jailhouse and run Linux afterwards in the root cell.
888
ec7972c9
ZY
889config ACRN_GUEST
890 bool "ACRN Guest support"
891 depends on X86_64
498ad393 892 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
893 help
894 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
895 a flexible, lightweight reference open-source hypervisor, built with
896 real-time and safety-criticality in mind. It is built for embedded
897 IOT with small footprint and real-time features. More details can be
898 found in https://projectacrn.org/.
899
59bd54a8
KS
900config INTEL_TDX_GUEST
901 bool "Intel TDX (Trust Domain Extensions) - Guest Support"
902 depends on X86_64 && CPU_SUP_INTEL
903 depends on X86_X2APIC
75d090fd 904 depends on EFI_STUB
41394e33 905 select ARCH_HAS_CC_PLATFORM
968b4931 906 select X86_MEM_ENCRYPT
77a512e3 907 select X86_MCE
75d090fd 908 select UNACCEPTED_MEMORY
59bd54a8
KS
909 help
910 Support running as a guest under Intel TDX. Without this support,
911 the guest kernel can not boot or run under TDX.
912 TDX includes memory encryption and integrity capabilities
913 which protect the confidentiality and integrity of guest
914 memory contents and CPU state. TDX guests are protected from
915 some attacks from the VMM.
916
758cd94a 917endif # HYPERVISOR_GUEST
97349135 918
506f1d07
SR
919source "arch/x86/Kconfig.cpu"
920
921config HPET_TIMER
3c2362e6 922 def_bool X86_64
506f1d07 923 prompt "HPET Timer Support" if X86_32
a7f7f624 924 help
8f9ca475
IM
925 Use the IA-PC HPET (High Precision Event Timer) to manage
926 time in preference to the PIT and RTC, if a HPET is
927 present.
928 HPET is the next generation timer replacing legacy 8254s.
929 The HPET provides a stable time base on SMP
930 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
931 as it is off-chip. The interface used is documented
932 in the HPET spec, revision 1.
506f1d07 933
8f9ca475
IM
934 You can safely choose Y here. However, HPET will only be
935 activated if the platform and the BIOS support this feature.
936 Otherwise the 8254 will be used for timing services.
506f1d07 937
8f9ca475 938 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
939
940config HPET_EMULATE_RTC
3c2362e6 941 def_bool y
3228e1dc 942 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 943
6a108a14 944# Mark as expert because too many people got it wrong.
506f1d07 945# The code disables itself when not needed.
7ae9392c
TP
946config DMI
947 default y
cf074402 948 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 949 bool "Enable DMI scanning" if EXPERT
a7f7f624 950 help
7ae9392c
TP
951 Enabled scanning of DMI to identify machine quirks. Say Y
952 here unless you have verified that your setup is not
953 affected by entries in the DMI blacklist. Required by PNP
954 BIOS code.
955
506f1d07 956config GART_IOMMU
38901f1c 957 bool "Old AMD GART IOMMU support"
a4ce5a48 958 select IOMMU_HELPER
506f1d07 959 select SWIOTLB
23ac4ae8 960 depends on X86_64 && PCI && AMD_NB
a7f7f624 961 help
ced3c42c
IM
962 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
963 GART based hardware IOMMUs.
964
965 The GART supports full DMA access for devices with 32-bit access
966 limitations, on systems with more than 3 GB. This is usually needed
967 for USB, sound, many IDE/SATA chipsets and some other devices.
968
969 Newer systems typically have a modern AMD IOMMU, supported via
970 the CONFIG_AMD_IOMMU=y config option.
971
972 In normal configurations this driver is only active when needed:
973 there's more than 3 GB of memory and the system contains a
974 32-bit limited device.
975
976 If unsure, say Y.
506f1d07 977
8b766b0f
MS
978config BOOT_VESA_SUPPORT
979 bool
980 help
981 If true, at least one selected framebuffer driver can take advantage
982 of VESA video modes set at an early boot stage via the vga= parameter.
506f1d07 983
1184dc2f 984config MAXSMP
ddb0c5a6 985 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 986 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 987 select CPUMASK_OFFSTACK
a7f7f624 988 help
ddb0c5a6 989 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 990 If unsure, say N.
506f1d07 991
aec6487e
IM
992#
993# The maximum number of CPUs supported:
994#
995# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
996# and which can be configured interactively in the
997# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
998#
999# The ranges are different on 32-bit and 64-bit kernels, depending on
1000# hardware capabilities and scalability features of the kernel.
1001#
1002# ( If MAXSMP is enabled we just use the highest possible value and disable
1003# interactive configuration. )
1004#
1005
1006config NR_CPUS_RANGE_BEGIN
a0d0bb4d 1007 int
aec6487e
IM
1008 default NR_CPUS_RANGE_END if MAXSMP
1009 default 1 if !SMP
1010 default 2
a0d0bb4d 1011
aec6487e 1012config NR_CPUS_RANGE_END
a0d0bb4d 1013 int
aec6487e
IM
1014 depends on X86_32
1015 default 64 if SMP && X86_BIGSMP
1016 default 8 if SMP && !X86_BIGSMP
1017 default 1 if !SMP
a0d0bb4d 1018
aec6487e 1019config NR_CPUS_RANGE_END
a0d0bb4d 1020 int
aec6487e 1021 depends on X86_64
1edae1ae
SW
1022 default 8192 if SMP && CPUMASK_OFFSTACK
1023 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 1024 default 1 if !SMP
a0d0bb4d 1025
aec6487e 1026config NR_CPUS_DEFAULT
a0d0bb4d
RD
1027 int
1028 depends on X86_32
aec6487e
IM
1029 default 32 if X86_BIGSMP
1030 default 8 if SMP
1031 default 1 if !SMP
a0d0bb4d 1032
aec6487e 1033config NR_CPUS_DEFAULT
a0d0bb4d
RD
1034 int
1035 depends on X86_64
aec6487e
IM
1036 default 8192 if MAXSMP
1037 default 64 if SMP
1038 default 1 if !SMP
a0d0bb4d 1039
506f1d07 1040config NR_CPUS
36f5101a 1041 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
1042 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1043 default NR_CPUS_DEFAULT
a7f7f624 1044 help
506f1d07 1045 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1046 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1047 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1048 minimum value which makes sense is 2.
1049
aec6487e
IM
1050 This is purely to save memory: each supported CPU adds about 8KB
1051 to the kernel image.
506f1d07 1052
66558b73
TC
1053config SCHED_CLUSTER
1054 bool "Cluster scheduler support"
1055 depends on SMP
1056 default y
1057 help
1058 Cluster scheduler support improves the CPU scheduler's decision
1059 making when dealing with machines that have clusters of CPUs.
1060 Cluster usually means a couple of CPUs which are placed closely
1061 by sharing mid-level caches, last-level cache tags or internal
1062 busses.
1063
506f1d07 1064config SCHED_SMT
dbe73364 1065 def_bool y if SMP
506f1d07
SR
1066
1067config SCHED_MC
3c2362e6
HH
1068 def_bool y
1069 prompt "Multi-core scheduler support"
c8e56d20 1070 depends on SMP
a7f7f624 1071 help
506f1d07
SR
1072 Multi-core scheduler support improves the CPU scheduler's decision
1073 making when dealing with multi-core CPU chips at a cost of slightly
1074 increased overhead in some places. If unsure say N here.
1075
de966cf4
TC
1076config SCHED_MC_PRIO
1077 bool "CPU core priorities scheduler support"
3598e577
ML
1078 depends on SCHED_MC
1079 select X86_INTEL_PSTATE if CPU_SUP_INTEL
1080 select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
0a21fc12 1081 select CPU_FREQ
de966cf4 1082 default y
a7f7f624 1083 help
0a21fc12
IM
1084 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1085 core ordering determined at manufacturing time, which allows
1086 certain cores to reach higher turbo frequencies (when running
1087 single threaded workloads) than others.
de966cf4 1088
0a21fc12
IM
1089 Enabling this kernel feature teaches the scheduler about
1090 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1091 scheduler's CPU selection logic accordingly, so that higher
1092 overall system performance can be achieved.
de966cf4 1093
0a21fc12 1094 This feature will have no effect on CPUs without this feature.
de966cf4 1095
0a21fc12 1096 If unsure say Y here.
5e76b2ab 1097
30b8b006 1098config UP_LATE_INIT
b03b016f
KK
1099 def_bool y
1100 depends on !SMP && X86_LOCAL_APIC
30b8b006 1101
506f1d07 1102config X86_UP_APIC
50849eef
JB
1103 bool "Local APIC support on uniprocessors" if !PCI_MSI
1104 default PCI_MSI
38a1dfda 1105 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1106 help
506f1d07
SR
1107 A local APIC (Advanced Programmable Interrupt Controller) is an
1108 integrated interrupt controller in the CPU. If you have a single-CPU
1109 system which has a processor with a local APIC, you can say Y here to
1110 enable and use it. If you say Y here even though your machine doesn't
1111 have a local APIC, then the kernel will still run with no slowdown at
1112 all. The local APIC supports CPU-generated self-interrupts (timer,
1113 performance counters), and the NMI watchdog which detects hard
1114 lockups.
1115
1116config X86_UP_IOAPIC
1117 bool "IO-APIC support on uniprocessors"
1118 depends on X86_UP_APIC
a7f7f624 1119 help
506f1d07
SR
1120 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1121 SMP-capable replacement for PC-style interrupt controllers. Most
1122 SMP systems and many recent uniprocessor systems have one.
1123
1124 If you have a single-CPU system with an IO-APIC, you can say Y here
1125 to use it. If you say Y here even though your machine doesn't have
1126 an IO-APIC, then the kernel will still run with no slowdown at all.
1127
1128config X86_LOCAL_APIC
3c2362e6 1129 def_bool y
0dbc6078 1130 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1131 select IRQ_DOMAIN_HIERARCHY
506f1d07 1132
2b5e22af
KS
1133config ACPI_MADT_WAKEUP
1134 def_bool y
1135 depends on X86_64
1136 depends on ACPI
1137 depends on SMP
1138 depends on X86_LOCAL_APIC
1139
506f1d07 1140config X86_IO_APIC
b1da1e71
JB
1141 def_bool y
1142 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1143
41b9eb26
SA
1144config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1145 bool "Reroute for broken boot IRQs"
41b9eb26 1146 depends on X86_IO_APIC
a7f7f624 1147 help
41b9eb26
SA
1148 This option enables a workaround that fixes a source of
1149 spurious interrupts. This is recommended when threaded
1150 interrupt handling is used on systems where the generation of
1151 superfluous "boot interrupts" cannot be disabled.
1152
1153 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1154 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1155 kernel does during interrupt handling). On chipsets where this
1156 boot IRQ generation cannot be disabled, this workaround keeps
1157 the original IRQ line masked so that only the equivalent "boot
1158 IRQ" is delivered to the CPUs. The workaround also tells the
1159 kernel to set up the IRQ handler on the boot IRQ line. In this
1160 way only one interrupt is delivered to the kernel. Otherwise
1161 the spurious second interrupt may cause the kernel to bring
1162 down (vital) interrupt lines.
1163
1164 Only affects "broken" chipsets. Interrupt sharing may be
1165 increased on these systems.
1166
506f1d07 1167config X86_MCE
bab9bc65 1168 bool "Machine Check / overheating reporting"
648ed940 1169 select GENERIC_ALLOCATOR
e57dbaf7 1170 default y
a7f7f624 1171 help
bab9bc65
AK
1172 Machine Check support allows the processor to notify the
1173 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1174 The action the kernel takes depends on the severity of the problem,
bab9bc65 1175 ranging from warning messages to halting the machine.
4efc0670 1176
5de97c9f
TL
1177config X86_MCELOG_LEGACY
1178 bool "Support for deprecated /dev/mcelog character device"
1179 depends on X86_MCE
a7f7f624 1180 help
5de97c9f
TL
1181 Enable support for /dev/mcelog which is needed by the old mcelog
1182 userspace logging daemon. Consider switching to the new generation
1183 rasdaemon solution.
1184
506f1d07 1185config X86_MCE_INTEL
3c2362e6
HH
1186 def_bool y
1187 prompt "Intel MCE features"
c1ebf835 1188 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1189 help
758cd94a
JH
1190 Additional support for intel specific MCE features such as
1191 the thermal monitor.
506f1d07
SR
1192
1193config X86_MCE_AMD
3c2362e6
HH
1194 def_bool y
1195 prompt "AMD MCE features"
d35fb312 1196 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1197 help
758cd94a
JH
1198 Additional support for AMD specific MCE features such as
1199 the DRAM Error Threshold.
506f1d07 1200
4efc0670 1201config X86_ANCIENT_MCE
6fc108a0 1202 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1203 depends on X86_32 && X86_MCE
a7f7f624 1204 help
cd13adcc 1205 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1206 systems. These typically need to be enabled explicitly on the command
cd13adcc 1207 line.
4efc0670 1208
b2762686
AK
1209config X86_MCE_THRESHOLD
1210 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1211 def_bool y
b2762686 1212
ea149b36 1213config X86_MCE_INJECT
bc8e80d5 1214 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1215 tristate "Machine check injector support"
a7f7f624 1216 help
ea149b36
AK
1217 Provide support for injecting machine checks for testing purposes.
1218 If you don't know what a machine check is and you don't do kernel
1219 QA it is safe to say n.
1220
07dc900e 1221source "arch/x86/events/Kconfig"
e633c65a 1222
5aef51c3 1223config X86_LEGACY_VM86
1e642812 1224 bool "Legacy VM86 support"
506f1d07 1225 depends on X86_32
a7f7f624 1226 help
5aef51c3
AL
1227 This option allows user programs to put the CPU into V8086
1228 mode, which is an 80286-era approximation of 16-bit real mode.
1229
1230 Some very old versions of X and/or vbetool require this option
1231 for user mode setting. Similarly, DOSEMU will use it if
1232 available to accelerate real mode DOS programs. However, any
1233 recent version of DOSEMU, X, or vbetool should be fully
1234 functional even without kernel VM86 support, as they will all
1e642812
IM
1235 fall back to software emulation. Nevertheless, if you are using
1236 a 16-bit DOS program where 16-bit performance matters, vm86
1237 mode might be faster than emulation and you might want to
1238 enable this option.
5aef51c3 1239
1e642812
IM
1240 Note that any app that works on a 64-bit kernel is unlikely to
1241 need this option, as 64-bit kernels don't, and can't, support
1242 V8086 mode. This option is also unrelated to 16-bit protected
1243 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1244
1e642812
IM
1245 Enabling this option increases the complexity of the kernel
1246 and slows down exception handling a tiny bit.
5aef51c3 1247
1e642812 1248 If unsure, say N here.
5aef51c3
AL
1249
1250config VM86
b03b016f
KK
1251 bool
1252 default X86_LEGACY_VM86
34273f41
PA
1253
1254config X86_16BIT
1255 bool "Enable support for 16-bit segments" if EXPERT
1256 default y
a5b9e5a2 1257 depends on MODIFY_LDT_SYSCALL
a7f7f624 1258 help
34273f41
PA
1259 This option is required by programs like Wine to run 16-bit
1260 protected mode legacy code on x86 processors. Disabling
1261 this option saves about 300 bytes on i386, or around 6K text
1262 plus 16K runtime memory on x86-64,
1263
1264config X86_ESPFIX32
1265 def_bool y
1266 depends on X86_16BIT && X86_32
506f1d07 1267
197725de
PA
1268config X86_ESPFIX64
1269 def_bool y
34273f41 1270 depends on X86_16BIT && X86_64
506f1d07 1271
1ad83c85 1272config X86_VSYSCALL_EMULATION
b03b016f
KK
1273 bool "Enable vsyscall emulation" if EXPERT
1274 default y
1275 depends on X86_64
a7f7f624 1276 help
758cd94a
JH
1277 This enables emulation of the legacy vsyscall page. Disabling
1278 it is roughly equivalent to booting with vsyscall=none, except
1279 that it will also disable the helpful warning if a program
1280 tries to use a vsyscall. With this option set to N, offending
1281 programs will just segfault, citing addresses of the form
1282 0xffffffffff600?00.
1ad83c85 1283
758cd94a
JH
1284 This option is required by many programs built before 2013, and
1285 care should be used even with newer programs if set to N.
1ad83c85 1286
758cd94a
JH
1287 Disabling this option saves about 7K of kernel size and
1288 possibly 4K of additional runtime pagetable memory.
1ad83c85 1289
111e7b15
TG
1290config X86_IOPL_IOPERM
1291 bool "IOPERM and IOPL Emulation"
a24ca997 1292 default y
a7f7f624 1293 help
111e7b15
TG
1294 This enables the ioperm() and iopl() syscalls which are necessary
1295 for legacy applications.
1296
c8137ace
TG
1297 Legacy IOPL support is an overbroad mechanism which allows user
1298 space aside of accessing all 65536 I/O ports also to disable
1299 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1300 capabilities and permission from potentially active security
1301 modules.
1302
1303 The emulation restricts the functionality of the syscall to
1304 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1305 ability to disable interrupts from user space which would be
1306 granted if the hardware IOPL mechanism would be used.
c8137ace 1307
506f1d07
SR
1308config TOSHIBA
1309 tristate "Toshiba Laptop support"
1310 depends on X86_32
a7f7f624 1311 help
506f1d07
SR
1312 This adds a driver to safely access the System Management Mode of
1313 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1314 not work on models with a Phoenix BIOS. The System Management Mode
1315 is used to set the BIOS and power saving options on Toshiba portables.
1316
1317 For information on utilities to make use of this driver see the
1318 Toshiba Linux utilities web site at:
1319 <http://www.buzzard.org.uk/toshiba/>.
1320
1321 Say Y if you intend to run this kernel on a Toshiba portable.
1322 Say N otherwise.
1323
506f1d07 1324config X86_REBOOTFIXUPS
9ba16087
JB
1325 bool "Enable X86 board specific fixups for reboot"
1326 depends on X86_32
a7f7f624 1327 help
506f1d07
SR
1328 This enables chipset and/or board specific fixups to be done
1329 in order to get reboot to work correctly. This is only needed on
1330 some combinations of hardware and BIOS. The symptom, for which
1331 this config is intended, is when reboot ends with a stalled/hung
1332 system.
1333
1334 Currently, the only fixup is for the Geode machines using
5e3a77e9 1335 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1336
1337 Say Y if you want to enable the fixup. Currently, it's safe to
1338 enable this option even if you don't need it.
1339 Say N otherwise.
1340
1341config MICROCODE
e6bcfdd7 1342 def_bool y
80030e3d 1343 depends on CPU_SUP_AMD || CPU_SUP_INTEL
80cc9f10 1344
fdbd4381
TG
1345config MICROCODE_INITRD32
1346 def_bool y
1347 depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1348
a77a94f8
BP
1349config MICROCODE_LATE_LOADING
1350 bool "Late microcode loading (DANGEROUS)"
c02f48e0 1351 default n
634ac23a 1352 depends on MICROCODE && SMP
a7f7f624 1353 help
a77a94f8
BP
1354 Loading microcode late, when the system is up and executing instructions
1355 is a tricky business and should be avoided if possible. Just the sequence
1356 of synchronizing all cores and SMT threads is one fragile dance which does
1357 not guarantee that cores might not softlock after the loading. Therefore,
9407bda8
TG
1358 use this at your own risk. Late loading taints the kernel unless the
1359 microcode header indicates that it is safe for late loading via the
1360 minimal revision check. This minimal revision check can be enforced on
1361 the kernel command line with "microcode.minrev=Y".
1362
1363config MICROCODE_LATE_FORCE_MINREV
1364 bool "Enforce late microcode loading minimal revision check"
1365 default n
1366 depends on MICROCODE_LATE_LOADING
1367 help
1368 To prevent that users load microcode late which modifies already
1369 in use features, newer microcode patches have a minimum revision field
1370 in the microcode header, which tells the kernel which minimum
1371 revision must be active in the CPU to safely load that new microcode
1372 late into the running system. If disabled the check will not
1373 be enforced but the kernel will be tainted when the minimal
1374 revision check fails.
1375
1376 This minimal revision check can also be controlled via the
1377 "microcode.minrev" parameter on the kernel command line.
1378
1379 If unsure say Y.
506f1d07
SR
1380
1381config X86_MSR
1382 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1383 help
506f1d07
SR
1384 This device gives privileged processes access to the x86
1385 Model-Specific Registers (MSRs). It is a character device with
1386 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1387 MSR accesses are directed to a specific CPU on multi-processor
1388 systems.
1389
1390config X86_CPUID
1391 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1392 help
506f1d07
SR
1393 This device gives processes access to the x86 CPUID instruction to
1394 be executed on a specific processor. It is a character device
1395 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1396 /dev/cpu/31/cpuid.
1397
1398choice
1399 prompt "High Memory Support"
6fc108a0 1400 default HIGHMEM4G
506f1d07
SR
1401 depends on X86_32
1402
1403config NOHIGHMEM
1404 bool "off"
a7f7f624 1405 help
506f1d07
SR
1406 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1407 However, the address space of 32-bit x86 processors is only 4
1408 Gigabytes large. That means that, if you have a large amount of
1409 physical memory, not all of it can be "permanently mapped" by the
1410 kernel. The physical memory that's not permanently mapped is called
1411 "high memory".
1412
1413 If you are compiling a kernel which will never run on a machine with
1414 more than 1 Gigabyte total physical RAM, answer "off" here (default
1415 choice and suitable for most users). This will result in a "3GB/1GB"
1416 split: 3GB are mapped so that each process sees a 3GB virtual memory
1417 space and the remaining part of the 4GB virtual memory space is used
1418 by the kernel to permanently map as much physical memory as
1419 possible.
1420
1421 If the machine has between 1 and 4 Gigabytes physical RAM, then
1422 answer "4GB" here.
1423
1424 If more than 4 Gigabytes is used then answer "64GB" here. This
1425 selection turns Intel PAE (Physical Address Extension) mode on.
1426 PAE implements 3-level paging on IA32 processors. PAE is fully
1427 supported by Linux, PAE mode is implemented on all recent Intel
1428 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1429 then the kernel will not boot on CPUs that don't support PAE!
1430
1431 The actual amount of total physical memory will either be
1432 auto detected or can be forced by using a kernel command line option
1433 such as "mem=256M". (Try "man bootparam" or see the documentation of
1434 your boot loader (lilo or loadlin) about how to pass options to the
1435 kernel at boot time.)
1436
1437 If unsure, say "off".
1438
1439config HIGHMEM4G
1440 bool "4GB"
a7f7f624 1441 help
506f1d07
SR
1442 Select this if you have a 32-bit processor and between 1 and 4
1443 gigabytes of physical RAM.
1444
1445config HIGHMEM64G
1446 bool "64GB"
88a2b4ed 1447 depends on X86_HAVE_PAE
506f1d07 1448 select X86_PAE
a7f7f624 1449 help
506f1d07
SR
1450 Select this if you have a 32-bit processor and more than 4
1451 gigabytes of physical RAM.
1452
1453endchoice
1454
1455choice
6a108a14 1456 prompt "Memory split" if EXPERT
506f1d07
SR
1457 default VMSPLIT_3G
1458 depends on X86_32
a7f7f624 1459 help
506f1d07
SR
1460 Select the desired split between kernel and user memory.
1461
1462 If the address range available to the kernel is less than the
1463 physical memory installed, the remaining memory will be available
1464 as "high memory". Accessing high memory is a little more costly
1465 than low memory, as it needs to be mapped into the kernel first.
1466 Note that increasing the kernel address space limits the range
1467 available to user programs, making the address space there
1468 tighter. Selecting anything other than the default 3G/1G split
1469 will also likely make your kernel incompatible with binary-only
1470 kernel modules.
1471
1472 If you are not absolutely sure what you are doing, leave this
1473 option alone!
1474
1475 config VMSPLIT_3G
1476 bool "3G/1G user/kernel split"
1477 config VMSPLIT_3G_OPT
1478 depends on !X86_PAE
1479 bool "3G/1G user/kernel split (for full 1G low memory)"
1480 config VMSPLIT_2G
1481 bool "2G/2G user/kernel split"
1482 config VMSPLIT_2G_OPT
1483 depends on !X86_PAE
1484 bool "2G/2G user/kernel split (for full 2G low memory)"
1485 config VMSPLIT_1G
1486 bool "1G/3G user/kernel split"
1487endchoice
1488
1489config PAGE_OFFSET
1490 hex
1491 default 0xB0000000 if VMSPLIT_3G_OPT
1492 default 0x80000000 if VMSPLIT_2G
1493 default 0x78000000 if VMSPLIT_2G_OPT
1494 default 0x40000000 if VMSPLIT_1G
1495 default 0xC0000000
1496 depends on X86_32
1497
1498config HIGHMEM
3c2362e6 1499 def_bool y
506f1d07 1500 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1501
1502config X86_PAE
9ba16087 1503 bool "PAE (Physical Address Extension) Support"
88a2b4ed 1504 depends on X86_32 && X86_HAVE_PAE
d4a451d5 1505 select PHYS_ADDR_T_64BIT
9d99c712 1506 select SWIOTLB
a7f7f624 1507 help
506f1d07
SR
1508 PAE is required for NX support, and furthermore enables
1509 larger swapspace support for non-overcommit purposes. It
1510 has the cost of more pagetable lookup overhead, and also
1511 consumes more pagetable space per process.
1512
77ef56e4
KS
1513config X86_5LEVEL
1514 bool "Enable 5-level page tables support"
18ec1eaf 1515 default y
eedb92ab 1516 select DYNAMIC_MEMORY_LAYOUT
162434e7 1517 select SPARSEMEM_VMEMMAP
77ef56e4 1518 depends on X86_64
a7f7f624 1519 help
77ef56e4 1520 5-level paging enables access to larger address space:
54628de6 1521 up to 128 PiB of virtual address space and 4 PiB of
77ef56e4
KS
1522 physical address space.
1523
1524 It will be supported by future Intel CPUs.
1525
6657fca0
KS
1526 A kernel with the option enabled can be booted on machines that
1527 support 4- or 5-level paging.
77ef56e4 1528
ff61f079 1529 See Documentation/arch/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1530 information.
1531
1532 Say N if unsure.
1533
10971ab2 1534config X86_DIRECT_GBPAGES
e5008abe 1535 def_bool y
2e1da13f 1536 depends on X86_64
a7f7f624 1537 help
10971ab2
IM
1538 Certain kernel features effectively disable kernel
1539 linear 1 GB mappings (even if the CPU otherwise
1540 supports them), so don't confuse the user by printing
1541 that we have them enabled.
9e899816 1542
5c280cf6
TG
1543config X86_CPA_STATISTICS
1544 bool "Enable statistic for Change Page Attribute"
1545 depends on DEBUG_FS
a7f7f624 1546 help
b75baaf3 1547 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1548 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1549 page mappings when mapping protections are changed.
1550
20f07a04
KS
1551config X86_MEM_ENCRYPT
1552 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1553 select DYNAMIC_PHYSICAL_MASK
20f07a04
KS
1554 def_bool n
1555
7744ccdb
TL
1556config AMD_MEM_ENCRYPT
1557 bool "AMD Secure Memory Encryption (SME) support"
1558 depends on X86_64 && CPU_SUP_AMD
6c321179 1559 depends on EFI_STUB
82fef0ad 1560 select DMA_COHERENT_POOL
ce9084ba 1561 select ARCH_USE_MEMREMAP_PROT
597cfe48 1562 select INSTRUCTION_DECODER
aa5a4611 1563 select ARCH_HAS_CC_PLATFORM
20f07a04 1564 select X86_MEM_ENCRYPT
6c321179 1565 select UNACCEPTED_MEMORY
c5529418 1566 select CRYPTO_LIB_AESGCM
a7f7f624 1567 help
7744ccdb
TL
1568 Say yes to enable support for the encryption of system memory.
1569 This requires an AMD processor that supports Secure Memory
1570 Encryption (SME).
1571
506f1d07
SR
1572# Common NUMA Features
1573config NUMA
e133f6ea 1574 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1575 depends on SMP
b5660ba7
PA
1576 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1577 default y if X86_BIGSMP
7ecd19cf 1578 select USE_PERCPU_NUMA_NODE_ID
0c436a58 1579 select OF_NUMA if OF
a7f7f624 1580 help
e133f6ea 1581 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1582
506f1d07
SR
1583 The kernel will try to allocate memory used by a CPU on the
1584 local memory controller of the CPU and add some more
1585 NUMA awareness to the kernel.
1586
c280ea5e 1587 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1588 (or later), AMD Opteron, or EM64T NUMA.
1589
b5660ba7 1590 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1591 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1592
1593 Otherwise, you should say N.
506f1d07 1594
eec1d4fa 1595config AMD_NUMA
3c2362e6
HH
1596 def_bool y
1597 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1598 depends on X86_64 && NUMA && PCI
a7f7f624 1599 help
eec1d4fa
HR
1600 Enable AMD NUMA node topology detection. You should say Y here if
1601 you have a multi processor AMD system. This uses an old method to
1602 read the NUMA configuration directly from the builtin Northbridge
1603 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1604 which also takes priority if both are compiled in.
506f1d07
SR
1605
1606config X86_64_ACPI_NUMA
3c2362e6
HH
1607 def_bool y
1608 prompt "ACPI NUMA detection"
506f1d07
SR
1609 depends on X86_64 && NUMA && ACPI && PCI
1610 select ACPI_NUMA
a7f7f624 1611 help
506f1d07
SR
1612 Enable ACPI SRAT based node topology detection.
1613
506f1d07 1614config NODES_SHIFT
d25e26b6 1615 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1616 range 1 10
1617 default "10" if MAXSMP
506f1d07 1618 default "6" if X86_64
506f1d07 1619 default "3"
a9ee6cf5 1620 depends on NUMA
a7f7f624 1621 help
1184dc2f 1622 Specify the maximum number of NUMA Nodes available on the target
692105b8 1623 system. Increases memory reserved to accommodate various tables.
506f1d07 1624
506f1d07
SR
1625config ARCH_FLATMEM_ENABLE
1626 def_bool y
3b16651f 1627 depends on X86_32 && !NUMA
506f1d07 1628
506f1d07
SR
1629config ARCH_SPARSEMEM_ENABLE
1630 def_bool y
6ea30386 1631 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1632 select SPARSEMEM_STATIC if X86_32
1633 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1634
3b16651f 1635config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1636 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1637
506f1d07
SR
1638config ARCH_SELECT_MEMORY_MODEL
1639 def_bool y
4eda2bc3 1640 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
506f1d07
SR
1641
1642config ARCH_MEMORY_PROBE
a0842b70 1643 bool "Enable sysfs memory/probe interface"
5c11f00b 1644 depends on MEMORY_HOTPLUG
a0842b70
TK
1645 help
1646 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1647 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1648 If you are unsure how to answer this question, answer N.
506f1d07 1649
3b16651f
TH
1650config ARCH_PROC_KCORE_TEXT
1651 def_bool y
1652 depends on X86_64 && PROC_KCORE
1653
a29815a3 1654config ILLEGAL_POINTER_VALUE
b03b016f
KK
1655 hex
1656 default 0 if X86_32
1657 default 0xdead000000000000 if X86_64
a29815a3 1658
7a67832c
DW
1659config X86_PMEM_LEGACY_DEVICE
1660 bool
1661
ec776ef6 1662config X86_PMEM_LEGACY
7a67832c 1663 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1664 depends on PHYS_ADDR_T_64BIT
1665 depends on BLK_DEV
7a67832c 1666 select X86_PMEM_LEGACY_DEVICE
7b27a862 1667 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1668 select LIBNVDIMM
ec776ef6
CH
1669 help
1670 Treat memory marked using the non-standard e820 type of 12 as used
1671 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1672 The kernel will offer these regions to the 'pmem' driver so
1673 they can be used for persistent storage.
1674
1675 Say Y if unsure.
1676
506f1d07
SR
1677config HIGHPTE
1678 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1679 depends on HIGHMEM
a7f7f624 1680 help
506f1d07
SR
1681 The VM uses one page table entry for each page of physical memory.
1682 For systems with a lot of RAM, this can be wasteful of precious
1683 low memory. Setting this option will put user-space page table
1684 entries in high memory.
1685
9f077871 1686config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1687 bool "Check for low memory corruption"
a7f7f624 1688 help
8f9ca475
IM
1689 Periodically check for memory corruption in low memory, which
1690 is suspected to be caused by BIOS. Even when enabled in the
1691 configuration, it is disabled at runtime. Enable it by
1692 setting "memory_corruption_check=1" on the kernel command
1693 line. By default it scans the low 64k of memory every 60
1694 seconds; see the memory_corruption_check_size and
1695 memory_corruption_check_period parameters in
8c27ceff 1696 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1697
1698 When enabled with the default parameters, this option has
1699 almost no overhead, as it reserves a relatively small amount
1700 of memory and scans it infrequently. It both detects corruption
1701 and prevents it from affecting the running system.
1702
1703 It is, however, intended as a diagnostic tool; if repeatable
1704 BIOS-originated corruption always affects the same memory,
1705 you can use memmap= to prevent the kernel from using that
1706 memory.
9f077871 1707
c885df50 1708config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1709 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1710 depends on X86_CHECK_BIOS_CORRUPTION
1711 default y
a7f7f624 1712 help
8f9ca475
IM
1713 Set whether the default state of memory_corruption_check is
1714 on or off.
c885df50 1715
506f1d07
SR
1716config MATH_EMULATION
1717 bool
a5b9e5a2 1718 depends on MODIFY_LDT_SYSCALL
87d6021b 1719 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1720 help
506f1d07
SR
1721 Linux can emulate a math coprocessor (used for floating point
1722 operations) if you don't have one. 486DX and Pentium processors have
1723 a math coprocessor built in, 486SX and 386 do not, unless you added
1724 a 487DX or 387, respectively. (The messages during boot time can
1725 give you some hints here ["man dmesg"].) Everyone needs either a
1726 coprocessor or this emulation.
1727
1728 If you don't have a math coprocessor, you need to say Y here; if you
1729 say Y here even though you have a coprocessor, the coprocessor will
1730 be used nevertheless. (This behavior can be changed with the kernel
1731 command line option "no387", which comes handy if your coprocessor
1732 is broken. Try "man bootparam" or see the documentation of your boot
1733 loader (lilo or loadlin) about how to pass options to the kernel at
1734 boot time.) This means that it is a good idea to say Y here if you
1735 intend to use this kernel on different machines.
1736
1737 More information about the internals of the Linux math coprocessor
1738 emulation can be found in <file:arch/x86/math-emu/README>.
1739
1740 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1741 kernel, it won't hurt.
1742
1743config MTRR
6fc108a0 1744 def_bool y
6a108a14 1745 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1746 help
506f1d07
SR
1747 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1748 the Memory Type Range Registers (MTRRs) may be used to control
1749 processor access to memory ranges. This is most useful if you have
1750 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1751 allows bus write transfers to be combined into a larger transfer
1752 before bursting over the PCI/AGP bus. This can increase performance
1753 of image write operations 2.5 times or more. Saying Y here creates a
1754 /proc/mtrr file which may be used to manipulate your processor's
1755 MTRRs. Typically the X server should use this.
1756
1757 This code has a reasonably generic interface so that similar
1758 control registers on other processors can be easily supported
1759 as well:
1760
1761 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1762 Registers (ARRs) which provide a similar functionality to MTRRs. For
1763 these, the ARRs are used to emulate the MTRRs.
1764 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1765 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1766 write-combining. All of these processors are supported by this code
1767 and it makes sense to say Y here if you have one of them.
1768
1769 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1770 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1771 can lead to all sorts of problems, so it's good to say Y here.
1772
1773 You can safely say Y even if your machine doesn't have MTRRs, you'll
1774 just add about 9 KB to your kernel.
1775
ff61f079 1776 See <file:Documentation/arch/x86/mtrr.rst> for more information.
506f1d07 1777
95ffa243 1778config MTRR_SANITIZER
2ffb3501 1779 def_bool y
95ffa243
YL
1780 prompt "MTRR cleanup support"
1781 depends on MTRR
a7f7f624 1782 help
aba3728c
TG
1783 Convert MTRR layout from continuous to discrete, so X drivers can
1784 add writeback entries.
95ffa243 1785
aba3728c 1786 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1787 The largest mtrr entry size for a continuous block can be set with
aba3728c 1788 mtrr_chunk_size.
95ffa243 1789
2ffb3501 1790 If unsure, say Y.
95ffa243
YL
1791
1792config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1793 int "MTRR cleanup enable value (0-1)"
1794 range 0 1
1795 default "0"
95ffa243 1796 depends on MTRR_SANITIZER
a7f7f624 1797 help
f5098d62 1798 Enable mtrr cleanup default value
95ffa243 1799
12031a62
YL
1800config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1801 int "MTRR cleanup spare reg num (0-7)"
1802 range 0 7
1803 default "1"
1804 depends on MTRR_SANITIZER
a7f7f624 1805 help
12031a62 1806 mtrr cleanup spare entries default, it can be changed via
aba3728c 1807 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1808
2e5d9c85 1809config X86_PAT
6fc108a0 1810 def_bool y
6a108a14 1811 prompt "x86 PAT support" if EXPERT
2a8a2719 1812 depends on MTRR
7a87225a 1813 select ARCH_USES_PG_ARCH_2
a7f7f624 1814 help
2e5d9c85 1815 Use PAT attributes to setup page level cache control.
042b78e4 1816
2e5d9c85 1817 PATs are the modern equivalents of MTRRs and are much more
1818 flexible than MTRRs.
1819
1820 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1821 spontaneous reboots) or a non-working video driver.
2e5d9c85 1822
1823 If unsure, say Y.
1824
b971880f 1825config X86_UMIP
796ebc81 1826 def_bool y
b971880f 1827 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1828 help
b971880f
BM
1829 User Mode Instruction Prevention (UMIP) is a security feature in
1830 some x86 processors. If enabled, a general protection fault is
1831 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1832 executed in user mode. These instructions unnecessarily expose
1833 information about the hardware state.
796ebc81
RN
1834
1835 The vast majority of applications do not use these instructions.
1836 For the very few that do, software emulation is provided in
1837 specific cases in protected and virtual-8086 modes. Emulated
1838 results are dummy.
aa35f896 1839
156ff4a5
PZ
1840config CC_HAS_IBT
1841 # GCC >= 9 and binutils >= 2.29
1842 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1843 # Clang/LLVM >= 14
262448f3
NC
1844 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1845 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
156ff4a5 1846 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
262448f3 1847 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
156ff4a5
PZ
1848 $(as-instr,endbr64)
1849
18e66b69
RE
1850config X86_CET
1851 def_bool n
1852 help
1853 CET features configured (Shadow stack or IBT)
1854
156ff4a5
PZ
1855config X86_KERNEL_IBT
1856 prompt "Indirect Branch Tracking"
4fd5f70c 1857 def_bool y
03f16cd0 1858 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
f6a2c2b2
NC
1859 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1860 depends on !LD_IS_LLD || LLD_VERSION >= 140000
03f16cd0 1861 select OBJTOOL
18e66b69 1862 select X86_CET
156ff4a5
PZ
1863 help
1864 Build the kernel with support for Indirect Branch Tracking, a
1865 hardware support course-grain forward-edge Control Flow Integrity
1866 protection. It enforces that all indirect calls must land on
1867 an ENDBR instruction, as such, the compiler will instrument the
1868 code with them to make this happen.
1869
ed53a0d9 1870 In addition to building the kernel with IBT, seal all functions that
4cdfc11b 1871 are not indirect call targets, avoiding them ever becoming one.
ed53a0d9
PZ
1872
1873 This requires LTO like objtool runs and will slow down the build. It
1874 does significantly reduce the number of ENDBR instructions in the
1875 kernel image.
1876
35e97790 1877config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1878 prompt "Memory Protection Keys"
35e97790 1879 def_bool y
284244a9 1880 # Note: only available in 64-bit mode
38f3e775 1881 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1882 select ARCH_USES_HIGH_VMA_FLAGS
1883 select ARCH_HAS_PKEYS
a7f7f624 1884 help
284244a9
DH
1885 Memory Protection Keys provides a mechanism for enforcing
1886 page-based protections, but without requiring modification of the
1887 page tables when an application changes protection domains.
1888
1eecbcdc 1889 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1890
1891 If unsure, say y.
35e97790 1892
5626f8d4
JG
1893config ARCH_PKEY_BITS
1894 int
1895 default 4
1896
db616173
MH
1897choice
1898 prompt "TSX enable mode"
1899 depends on CPU_SUP_INTEL
1900 default X86_INTEL_TSX_MODE_OFF
1901 help
1902 Intel's TSX (Transactional Synchronization Extensions) feature
1903 allows to optimize locking protocols through lock elision which
1904 can lead to a noticeable performance boost.
1905
1906 On the other hand it has been shown that TSX can be exploited
1907 to form side channel attacks (e.g. TAA) and chances are there
1908 will be more of those attacks discovered in the future.
1909
1910 Therefore TSX is not enabled by default (aka tsx=off). An admin
1911 might override this decision by tsx=on the command line parameter.
1912 Even with TSX enabled, the kernel will attempt to enable the best
1913 possible TAA mitigation setting depending on the microcode available
1914 for the particular machine.
1915
1916 This option allows to set the default tsx mode between tsx=on, =off
1917 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1918 details.
1919
1920 Say off if not sure, auto if TSX is in use but it should be used on safe
1921 platforms or on if TSX is in use and the security aspect of tsx is not
1922 relevant.
1923
1924config X86_INTEL_TSX_MODE_OFF
1925 bool "off"
1926 help
1927 TSX is disabled if possible - equals to tsx=off command line parameter.
1928
1929config X86_INTEL_TSX_MODE_ON
1930 bool "on"
1931 help
1932 TSX is always enabled on TSX capable HW - equals the tsx=on command
1933 line parameter.
1934
1935config X86_INTEL_TSX_MODE_AUTO
1936 bool "auto"
1937 help
1938 TSX is enabled on TSX capable HW that is believed to be safe against
1939 side channel attacks- equals the tsx=auto command line parameter.
1940endchoice
1941
e7e05452
SC
1942config X86_SGX
1943 bool "Software Guard eXtensions (SGX)"
b8d1d163 1944 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
e7e05452
SC
1945 depends on CRYPTO=y
1946 depends on CRYPTO_SHA256=y
e7e05452 1947 select MMU_NOTIFIER
901ddbb9 1948 select NUMA_KEEP_MEMINFO if NUMA
40e0e784 1949 select XARRAY_MULTI
e7e05452
SC
1950 help
1951 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1952 that can be used by applications to set aside private regions of code
1953 and data, referred to as enclaves. An enclave's private memory can
1954 only be accessed by code running within the enclave. Accesses from
1955 outside the enclave, including other enclaves, are disallowed by
1956 hardware.
1957
1958 If unsure, say N.
1959
18e66b69
RE
1960config X86_USER_SHADOW_STACK
1961 bool "X86 userspace shadow stack"
1962 depends on AS_WRUSS
1963 depends on X86_64
1964 select ARCH_USES_HIGH_VMA_FLAGS
bcc9d04e 1965 select ARCH_HAS_USER_SHADOW_STACK
18e66b69
RE
1966 select X86_CET
1967 help
1968 Shadow stack protection is a hardware feature that detects function
1969 return address corruption. This helps mitigate ROP attacks.
1970 Applications must be enabled to use it, and old userspace does not
1971 get protection "for free".
1972
1973 CPUs supporting shadow stacks were first released in 2020.
1974
54acee60 1975 See Documentation/arch/x86/shstk.rst for more information.
18e66b69
RE
1976
1977 If unsure, say N.
1978
c33621b4
KH
1979config INTEL_TDX_HOST
1980 bool "Intel Trust Domain Extensions (TDX) host support"
1981 depends on CPU_SUP_INTEL
1982 depends on X86_64
1983 depends on KVM_INTEL
3115cabd 1984 depends on X86_X2APIC
abe8dbab 1985 select ARCH_KEEP_MEMBLOCK
ac3a2208 1986 depends on CONTIG_ALLOC
cb8eb06d 1987 depends on !KEXEC_CORE
83e1bdc9 1988 depends on X86_MCE
c33621b4
KH
1989 help
1990 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1991 host and certain physical attacks. This option enables necessary TDX
1992 support in the host kernel to run confidential VMs.
1993
1994 If unsure, say N.
1995
506f1d07 1996config EFI
9ba16087 1997 bool "EFI runtime service support"
5b83683f 1998 depends on ACPI
f6ce5002 1999 select UCS2_STRING
022ee6c5 2000 select EFI_RUNTIME_WRAPPERS
1ff2fc02 2001 select ARCH_USE_MEMREMAP_PROT
aba7e066 2002 select EFI_RUNTIME_MAP if KEXEC_CORE
a7f7f624 2003 help
8f9ca475
IM
2004 This enables the kernel to use EFI runtime services that are
2005 available (such as the EFI variable services).
506f1d07 2006
8f9ca475
IM
2007 This option is only useful on systems that have EFI firmware.
2008 In addition, you should use the latest ELILO loader available
2009 at <http://elilo.sourceforge.net> in order to take advantage
2010 of EFI runtime services. However, even with this option, the
2011 resultant kernel should continue to boot on existing non-EFI
2012 platforms.
506f1d07 2013
291f3632 2014config EFI_STUB
8f24f8c2 2015 bool "EFI stub support"
c6dbd3e5 2016 depends on EFI
8f24f8c2 2017 select RELOCATABLE
a7f7f624 2018 help
8f24f8c2 2019 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
2020 by EFI firmware without the use of a bootloader.
2021
4f4cfa6c 2022 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 2023
cc3fdda2
AB
2024config EFI_HANDOVER_PROTOCOL
2025 bool "EFI handover protocol (DEPRECATED)"
2026 depends on EFI_STUB
2027 default y
2028 help
2029 Select this in order to include support for the deprecated EFI
2030 handover protocol, which defines alternative entry points into the
2031 EFI stub. This is a practice that has no basis in the UEFI
2032 specification, and requires a priori knowledge on the part of the
2033 bootloader about Linux/x86 specific ways of passing the command line
2034 and initrd, and where in memory those assets may be loaded.
2035
2036 If in doubt, say Y. Even though the corresponding support is not
2037 present in upstream GRUB or other bootloaders, most distros build
2038 GRUB with numerous downstream patches applied, and may rely on the
2039 handover protocol as as result.
2040
7d453eee
MF
2041config EFI_MIXED
2042 bool "EFI mixed-mode support"
2043 depends on EFI_STUB && X86_64
a7f7f624 2044 help
758cd94a
JH
2045 Enabling this feature allows a 64-bit kernel to be booted
2046 on a 32-bit firmware, provided that your CPU supports 64-bit
2047 mode.
7d453eee 2048
758cd94a
JH
2049 Note that it is not possible to boot a mixed-mode enabled
2050 kernel via the EFI boot stub - a bootloader that supports
2051 the EFI handover protocol must be used.
7d453eee 2052
758cd94a 2053 If unsure, say N.
7d453eee 2054
1fff234d
AB
2055config EFI_RUNTIME_MAP
2056 bool "Export EFI runtime maps to sysfs" if EXPERT
2057 depends on EFI
1fff234d
AB
2058 help
2059 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2060 That memory map is required by the 2nd kernel to set up EFI virtual
2061 mappings after kexec, but can also be used for debugging purposes.
2062
2063 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2064
8636a1f9 2065source "kernel/Kconfig.hz"
506f1d07 2066
6af51380
ED
2067config ARCH_SUPPORTS_KEXEC
2068 def_bool y
74ca317c 2069
6af51380 2070config ARCH_SUPPORTS_KEXEC_FILE
c1ad12ee 2071 def_bool X86_64
b799a09f 2072
6af51380
ED
2073config ARCH_SELECTS_KEXEC_FILE
2074 def_bool y
74ca317c 2075 depends on KEXEC_FILE
6af51380 2076 select HAVE_IMA_KEXEC if IMA
d8eb8940 2077
e6265fe7 2078config ARCH_SUPPORTS_KEXEC_PURGATORY
c1ad12ee 2079 def_bool y
99d5cadf 2080
6af51380
ED
2081config ARCH_SUPPORTS_KEXEC_SIG
2082 def_bool y
8e7d8381 2083
6af51380
ED
2084config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2085 def_bool y
99d5cadf 2086
6af51380
ED
2087config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2088 def_bool y
8e7d8381 2089
6af51380
ED
2090config ARCH_SUPPORTS_KEXEC_JUMP
2091 def_bool y
506f1d07 2092
6af51380
ED
2093config ARCH_SUPPORTS_CRASH_DUMP
2094 def_bool X86_64 || (X86_32 && HIGHMEM)
3ab83521 2095
31daa343
DV
2096config ARCH_DEFAULT_CRASH_DUMP
2097 def_bool y
2098
ea53ad9c
ED
2099config ARCH_SUPPORTS_CRASH_HOTPLUG
2100 def_bool y
3ab83521 2101
9c08a2a1 2102config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
85fcde40 2103 def_bool CRASH_RESERVE
9c08a2a1 2104
506f1d07 2105config PHYSICAL_START
6a108a14 2106 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2107 default "0x1000000"
a7f7f624 2108 help
506f1d07
SR
2109 This gives the physical address where the kernel is loaded.
2110
43b1d3e6
CK
2111 If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2112 will decompress itself to above physical address and run from there.
2113 Otherwise, bzImage will run from the address where it has been loaded
2114 by the boot loader. The only exception is if it is loaded below the
2115 above physical address, in which case it will relocate itself there.
506f1d07
SR
2116
2117 In normal kdump cases one does not have to set/change this option
2118 as now bzImage can be compiled as a completely relocatable image
2119 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2120 address. This option is mainly useful for the folks who don't want
2121 to use a bzImage for capturing the crash dump and want to use a
2122 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2123 to be specifically compiled to run from a specific memory area
2124 (normally a reserved region) and this option comes handy.
2125
ceefccc9
PA
2126 So if you are using bzImage for capturing the crash dump,
2127 leave the value here unchanged to 0x1000000 and set
2128 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2129 for capturing the crash dump change this value to start of
2130 the reserved region. In other words, it can be set based on
2131 the "X" value as specified in the "crashkernel=YM@XM"
2132 command line boot parameter passed to the panic-ed
330d4810 2133 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2134 for more details about crash dumps.
506f1d07
SR
2135
2136 Usage of bzImage for capturing the crash dump is recommended as
2137 one does not have to build two kernels. Same kernel can be used
2138 as production kernel and capture kernel. Above option should have
2139 gone away after relocatable bzImage support is introduced. But it
2140 is present because there are users out there who continue to use
2141 vmlinux for dump capture. This option should go away down the
2142 line.
2143
2144 Don't change this unless you know what you are doing.
2145
2146config RELOCATABLE
26717808
PA
2147 bool "Build a relocatable kernel"
2148 default y
a7f7f624 2149 help
506f1d07
SR
2150 This builds a kernel image that retains relocation information
2151 so it can be loaded someplace besides the default 1MB.
2152 The relocations tend to make the kernel binary about 10% larger,
2153 but are discarded at runtime.
2154
2155 One use is for the kexec on panic case where the recovery kernel
2156 must live at a different physical address than the primary
2157 kernel.
2158
2159 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2160 it has been loaded at and the compile time physical address
8ab3820f 2161 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2162
8ab3820f 2163config RANDOMIZE_BASE
e8581e3d 2164 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2165 depends on RELOCATABLE
6807c846 2166 default y
a7f7f624 2167 help
e8581e3d
BH
2168 In support of Kernel Address Space Layout Randomization (KASLR),
2169 this randomizes the physical address at which the kernel image
2170 is decompressed and the virtual address where the kernel
2171 image is mapped, as a security feature that deters exploit
2172 attempts relying on knowledge of the location of kernel
2173 code internals.
2174
ed9f007e
KC
2175 On 64-bit, the kernel physical and virtual addresses are
2176 randomized separately. The physical address will be anywhere
2177 between 16MB and the top of physical memory (up to 64TB). The
2178 virtual address will be randomized from 16MB up to 1GB (9 bits
2179 of entropy). Note that this also reduces the memory space
2180 available to kernel modules from 1.5GB to 1GB.
2181
2182 On 32-bit, the kernel physical and virtual addresses are
2183 randomized together. They will be randomized from 16MB up to
2184 512MB (8 bits of entropy).
e8581e3d
BH
2185
2186 Entropy is generated using the RDRAND instruction if it is
2187 supported. If RDTSC is supported, its value is mixed into
2188 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2189 supported, then entropy is read from the i8254 timer. The
2190 usable entropy is limited by the kernel being built using
2191 2GB addressing, and that PHYSICAL_ALIGN must be at a
2192 minimum of 2MB. As a result, only 10 bits of entropy are
2193 theoretically possible, but the implementations are further
2194 limited due to memory layouts.
e8581e3d 2195
6807c846 2196 If unsure, say Y.
8ab3820f
KC
2197
2198# Relocation on x86 needs some additional build support
845adf72
PA
2199config X86_NEED_RELOCS
2200 def_bool y
8ab3820f 2201 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2202
506f1d07 2203config PHYSICAL_ALIGN
a0215061 2204 hex "Alignment value to which kernel should be aligned"
8ab3820f 2205 default "0x200000"
a0215061
KC
2206 range 0x2000 0x1000000 if X86_32
2207 range 0x200000 0x1000000 if X86_64
a7f7f624 2208 help
506f1d07
SR
2209 This value puts the alignment restrictions on physical address
2210 where kernel is loaded and run from. Kernel is compiled for an
2211 address which meets above alignment restriction.
2212
2213 If bootloader loads the kernel at a non-aligned address and
2214 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2215 address aligned to above value and run from there.
2216
2217 If bootloader loads the kernel at a non-aligned address and
2218 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2219 load address and decompress itself to the address it has been
2220 compiled for and run from there. The address for which kernel is
2221 compiled already meets above alignment restrictions. Hence the
2222 end result is that kernel runs from a physical address meeting
2223 above alignment restrictions.
2224
a0215061
KC
2225 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2226 this value must be a multiple of 0x200000.
2227
506f1d07
SR
2228 Don't change this unless you know what you are doing.
2229
eedb92ab
KS
2230config DYNAMIC_MEMORY_LAYOUT
2231 bool
a7f7f624 2232 help
eedb92ab
KS
2233 This option makes base addresses of vmalloc and vmemmap as well as
2234 __PAGE_OFFSET movable during boot.
2235
0483e1fa
TG
2236config RANDOMIZE_MEMORY
2237 bool "Randomize the kernel memory sections"
2238 depends on X86_64
2239 depends on RANDOMIZE_BASE
eedb92ab 2240 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2241 default RANDOMIZE_BASE
a7f7f624 2242 help
758cd94a
JH
2243 Randomizes the base virtual address of kernel memory sections
2244 (physical memory mapping, vmalloc & vmemmap). This security feature
2245 makes exploits relying on predictable memory locations less reliable.
0483e1fa 2246
758cd94a
JH
2247 The order of allocations remains unchanged. Entropy is generated in
2248 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2249 configuration have in average 30,000 different possible virtual
2250 addresses for each memory section.
0483e1fa 2251
758cd94a 2252 If unsure, say Y.
0483e1fa 2253
90397a41
TG
2254config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2255 hex "Physical memory mapping padding" if EXPERT
2256 depends on RANDOMIZE_MEMORY
2257 default "0xa" if MEMORY_HOTPLUG
2258 default "0x0"
2259 range 0x1 0x40 if MEMORY_HOTPLUG
2260 range 0x0 0x40
a7f7f624 2261 help
758cd94a
JH
2262 Define the padding in terabytes added to the existing physical
2263 memory size during kernel memory randomization. It is useful
2264 for memory hotplug support but reduces the entropy available for
2265 address randomization.
90397a41 2266
758cd94a 2267 If unsure, leave at the default value.
90397a41 2268
6449dcb0
KS
2269config ADDRESS_MASKING
2270 bool "Linear Address Masking support"
2271 depends on X86_64
3267cb6d 2272 depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
6449dcb0
KS
2273 help
2274 Linear Address Masking (LAM) modifies the checking that is applied
2275 to 64-bit linear addresses, allowing software to use of the
2276 untranslated address bits for metadata.
2277
2278 The capability can be used for efficient address sanitizers (ASAN)
2279 implementation and for optimizations in JITs.
2280
506f1d07 2281config HOTPLUG_CPU
bebd024e 2282 def_bool y
40b31360 2283 depends on SMP
506f1d07
SR
2284
2285config COMPAT_VDSO
b0b49f26
AL
2286 def_bool n
2287 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2288 depends on COMPAT_32
a7f7f624 2289 help
b0b49f26
AL
2290 Certain buggy versions of glibc will crash if they are
2291 presented with a 32-bit vDSO that is not mapped at the address
2292 indicated in its segment table.
e84446de 2293
b0b49f26
AL
2294 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2295 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2296 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2297 the only released version with the bug, but OpenSUSE 9
2298 contains a buggy "glibc 2.3.2".
506f1d07 2299
b0b49f26
AL
2300 The symptom of the bug is that everything crashes on startup, saying:
2301 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2302
2303 Saying Y here changes the default value of the vdso32 boot
2304 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2305 This works around the glibc bug but hurts performance.
2306
2307 If unsure, say N: if you are compiling your own kernel, you
2308 are unlikely to be using a buggy version of glibc.
506f1d07 2309
3dc33bd3
KC
2310choice
2311 prompt "vsyscall table for legacy applications"
2312 depends on X86_64
625b7b7f 2313 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2314 help
2315 Legacy user code that does not know how to find the vDSO expects
2316 to be able to issue three syscalls by calling fixed addresses in
2317 kernel space. Since this location is not randomized with ASLR,
2318 it can be used to assist security vulnerability exploitation.
2319
2320 This setting can be changed at boot time via the kernel command
bf00745e
AL
2321 line parameter vsyscall=[emulate|xonly|none]. Emulate mode
2322 is deprecated and can only be enabled using the kernel command
2323 line.
3dc33bd3
KC
2324
2325 On a system with recent enough glibc (2.14 or newer) and no
2326 static binaries, you can say None without a performance penalty
2327 to improve security.
2328
bd49e16e 2329 If unsure, select "Emulate execution only".
3dc33bd3 2330
bd49e16e
AL
2331 config LEGACY_VSYSCALL_XONLY
2332 bool "Emulate execution only"
2333 help
2334 The kernel traps and emulates calls into the fixed vsyscall
2335 address mapping and does not allow reads. This
2336 configuration is recommended when userspace might use the
2337 legacy vsyscall area but support for legacy binary
2338 instrumentation of legacy code is not needed. It mitigates
2339 certain uses of the vsyscall area as an ASLR-bypassing
2340 buffer.
3dc33bd3
KC
2341
2342 config LEGACY_VSYSCALL_NONE
2343 bool "None"
2344 help
2345 There will be no vsyscall mapping at all. This will
2346 eliminate any risk of ASLR bypass due to the vsyscall
2347 fixed address mapping. Attempts to use the vsyscalls
2348 will be reported to dmesg, so that either old or
2349 malicious userspace programs can be identified.
2350
2351endchoice
2352
516cbf37
TB
2353config CMDLINE_BOOL
2354 bool "Built-in kernel command line"
a7f7f624 2355 help
516cbf37
TB
2356 Allow for specifying boot arguments to the kernel at
2357 build time. On some systems (e.g. embedded ones), it is
2358 necessary or convenient to provide some or all of the
2359 kernel boot arguments with the kernel itself (that is,
2360 to not rely on the boot loader to provide them.)
2361
2362 To compile command line arguments into the kernel,
2363 set this option to 'Y', then fill in the
69711ca1 2364 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2365
2366 Systems with fully functional boot loaders (i.e. non-embedded)
2367 should leave this option set to 'N'.
2368
2369config CMDLINE
2370 string "Built-in kernel command string"
2371 depends on CMDLINE_BOOL
2372 default ""
a7f7f624 2373 help
516cbf37
TB
2374 Enter arguments here that should be compiled into the kernel
2375 image and used at boot time. If the boot loader provides a
2376 command line at boot time, it is appended to this string to
2377 form the full kernel command line, when the system boots.
2378
2379 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2380 change this behavior.
2381
2382 In most cases, the command line (whether built-in or provided
2383 by the boot loader) should specify the device for the root
2384 file system.
2385
2386config CMDLINE_OVERRIDE
2387 bool "Built-in command line overrides boot loader arguments"
645e6466 2388 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2389 help
516cbf37
TB
2390 Set this option to 'Y' to have the kernel ignore the boot loader
2391 command line, and use ONLY the built-in command line.
2392
2393 This is used to work around broken boot loaders. This should
2394 be set to 'N' under normal conditions.
2395
a5b9e5a2
AL
2396config MODIFY_LDT_SYSCALL
2397 bool "Enable the LDT (local descriptor table)" if EXPERT
2398 default y
a7f7f624 2399 help
a5b9e5a2
AL
2400 Linux can allow user programs to install a per-process x86
2401 Local Descriptor Table (LDT) using the modify_ldt(2) system
2402 call. This is required to run 16-bit or segmented code such as
2403 DOSEMU or some Wine programs. It is also used by some very old
2404 threading libraries.
2405
2406 Enabling this feature adds a small amount of overhead to
2407 context switches and increases the low-level kernel attack
2408 surface. Disabling it removes the modify_ldt(2) system call.
2409
2410 Saying 'N' here may make sense for embedded or server kernels.
2411
3aac3ebe
TG
2412config STRICT_SIGALTSTACK_SIZE
2413 bool "Enforce strict size checking for sigaltstack"
2414 depends on DYNAMIC_SIGFRAME
2415 help
2416 For historical reasons MINSIGSTKSZ is a constant which became
2417 already too small with AVX512 support. Add a mechanism to
2418 enforce strict checking of the sigaltstack size against the
2419 real size of the FPU frame. This option enables the check
2420 by default. It can also be controlled via the kernel command
2421 line option 'strict_sas_size' independent of this config
2422 switch. Enabling it might break existing applications which
2423 allocate a too small sigaltstack but 'work' because they
2424 never get a signal delivered.
2425
2426 Say 'N' unless you want to really enforce this check.
2427
d6f635bc
KC
2428config CFI_AUTO_DEFAULT
2429 bool "Attempt to use FineIBT by default at boot time"
2430 depends on FINEIBT
2431 default y
2432 help
2433 Attempt to use FineIBT by default at boot time. If enabled,
2434 this is the same as booting with "cfi=auto". If disabled,
2435 this is the same as booting with "cfi=kcfi".
2436
b700e7f0
SJ
2437source "kernel/livepatch/Kconfig"
2438
350afa8a
RB
2439config X86_BUS_LOCK_DETECT
2440 bool "Split Lock Detect and Bus Lock Detect support"
408eb741 2441 depends on CPU_SUP_INTEL || CPU_SUP_AMD
350afa8a
RB
2442 default y
2443 help
2444 Enable Split Lock Detect and Bus Lock Detect functionalities.
2445 See <file:Documentation/arch/x86/buslock.rst> for more information.
2446
506f1d07
SR
2447endmenu
2448
1ca3683c 2449config CC_HAS_NAMED_AS
47ff30cc
UB
2450 def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2451 depends on CC_IS_GCC
1ca3683c 2452
9ebe5500 2453config CC_HAS_NAMED_AS_FIXED_SANITIZERS
f61f02d1 2454 def_bool CC_IS_GCC && GCC_VERSION >= 130300
1ca3683c
UB
2455
2456config USE_X86_SEG_SUPPORT
2457 def_bool y
e29aad08
UB
2458 depends on CC_HAS_NAMED_AS
2459 #
9ebe5500
UB
2460 # -fsanitize=kernel-address (KASAN) and -fsanitize=thread
2461 # (KCSAN) are incompatible with named address spaces with
2462 # GCC < 13.3 - see GCC PR sanitizer/111736.
e29aad08 2463 #
9ebe5500 2464 depends on !(KASAN || KCSAN) || CC_HAS_NAMED_AS_FIXED_SANITIZERS
1ca3683c 2465
f43b9876
PZ
2466config CC_HAS_SLS
2467 def_bool $(cc-option,-mharden-sls=all)
2468
2469config CC_HAS_RETURN_THUNK
2470 def_bool $(cc-option,-mfunction-return=thunk-extern)
2471
bea75b33
TG
2472config CC_HAS_ENTRY_PADDING
2473 def_bool $(cc-option,-fpatchable-function-entry=16,16)
2474
2475config FUNCTION_PADDING_CFI
2476 int
2477 default 59 if FUNCTION_ALIGNMENT_64B
2478 default 27 if FUNCTION_ALIGNMENT_32B
2479 default 11 if FUNCTION_ALIGNMENT_16B
2480 default 3 if FUNCTION_ALIGNMENT_8B
2481 default 0
2482
2483# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2484# except Kconfig can't do arithmetic :/
2485config FUNCTION_PADDING_BYTES
2486 int
2487 default FUNCTION_PADDING_CFI if CFI_CLANG
2488 default FUNCTION_ALIGNMENT
2489
931ab636
PZ
2490config CALL_PADDING
2491 def_bool n
2492 depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2493 select FUNCTION_ALIGNMENT_16B
2494
2495config FINEIBT
2496 def_bool y
aefb2f2e 2497 depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
931ab636
PZ
2498 select CALL_PADDING
2499
8f7c0d8b
TG
2500config HAVE_CALL_THUNKS
2501 def_bool y
0911b8c5 2502 depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
8f7c0d8b
TG
2503
2504config CALL_THUNKS
2505 def_bool n
931ab636 2506 select CALL_PADDING
8f7c0d8b 2507
b341b20d
PZ
2508config PREFIX_SYMBOLS
2509 def_bool y
931ab636 2510 depends on CALL_PADDING && !CFI_CLANG
b341b20d 2511
fe42754b
SC
2512menuconfig CPU_MITIGATIONS
2513 bool "Mitigations for CPU vulnerabilities"
f43b9876
PZ
2514 default y
2515 help
fe42754b
SC
2516 Say Y here to enable options which enable mitigations for hardware
2517 vulnerabilities (usually related to speculative execution).
ce0abef6
SC
2518 Mitigations can be disabled or restricted to SMT systems at runtime
2519 via the "mitigations" kernel parameter.
f43b9876 2520
ce0abef6
SC
2521 If you say N, all mitigations will be disabled. This CANNOT be
2522 overridden at runtime.
2523
2524 Say 'Y', unless you really know what you are doing.
f43b9876 2525
fe42754b 2526if CPU_MITIGATIONS
f43b9876 2527
ea4654e0 2528config MITIGATION_PAGE_TABLE_ISOLATION
f43b9876
PZ
2529 bool "Remove the kernel mapping in user mode"
2530 default y
2531 depends on (X86_64 || X86_PAE)
2532 help
2533 This feature reduces the number of hardware side channels by
2534 ensuring that the majority of kernel addresses are not mapped
2535 into userspace.
2536
ff61f079 2537 See Documentation/arch/x86/pti.rst for more details.
f43b9876 2538
aefb2f2e 2539config MITIGATION_RETPOLINE
f43b9876
PZ
2540 bool "Avoid speculative indirect branches in kernel"
2541 select OBJTOOL if HAVE_OBJTOOL
2542 default y
2543 help
2544 Compile kernel with the retpoline compiler options to guard against
2545 kernel-to-user data leaks by avoiding speculative indirect
2546 branches. Requires a compiler with -mindirect-branch=thunk-extern
2547 support for full protection. The kernel may run slower.
2548
0911b8c5 2549config MITIGATION_RETHUNK
f43b9876 2550 bool "Enable return-thunks"
aefb2f2e 2551 depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
f43b9876 2552 select OBJTOOL if HAVE_OBJTOOL
b648ab48 2553 default y if X86_64
f43b9876
PZ
2554 help
2555 Compile the kernel with the return-thunks compiler option to guard
2556 against kernel-to-user data leaks by avoiding return speculation.
2557 Requires a compiler with -mfunction-return=thunk-extern
2558 support for full protection. The kernel may run slower.
2559
ac61d439 2560config MITIGATION_UNRET_ENTRY
f43b9876 2561 bool "Enable UNRET on kernel entry"
0911b8c5 2562 depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
f43b9876
PZ
2563 default y
2564 help
2565 Compile the kernel with support for the retbleed=unret mitigation.
2566
5fa31af3 2567config MITIGATION_CALL_DEPTH_TRACKING
80e4c1cd
TG
2568 bool "Mitigate RSB underflow with call depth tracking"
2569 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2570 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2571 select CALL_THUNKS
2572 default y
2573 help
2574 Compile the kernel with call depth tracking to mitigate the Intel
86e39b94
BL
2575 SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2576 by default and needs to be enabled on the kernel command line via the
2577 retbleed=stuff option. For non-affected systems the overhead of this
2578 option is marginal as the call depth tracking is using run-time
2579 generated call thunks in a compiler generated padding area and call
2580 patching. This increases text size by ~5%. For non affected systems
2581 this space is unused. On affected SKL systems this results in a
2582 significant performance gain over the IBRS mitigation.
80e4c1cd 2583
e81dc127
TG
2584config CALL_THUNKS_DEBUG
2585 bool "Enable call thunks and call depth tracking debugging"
5fa31af3 2586 depends on MITIGATION_CALL_DEPTH_TRACKING
e81dc127
TG
2587 select FUNCTION_ALIGNMENT_32B
2588 default n
2589 help
2590 Enable call/ret counters for imbalance detection and build in
2591 a noisy dmesg about callthunks generation and call patching for
2592 trouble shooting. The debug prints need to be enabled on the
2593 kernel command line with 'debug-callthunks'.
54628de6
RD
2594 Only enable this when you are debugging call thunks as this
2595 creates a noticeable runtime overhead. If unsure say N.
80e4c1cd 2596
e0b8fcfa 2597config MITIGATION_IBPB_ENTRY
f43b9876 2598 bool "Enable IBPB on kernel entry"
b648ab48 2599 depends on CPU_SUP_AMD && X86_64
f43b9876
PZ
2600 default y
2601 help
318e8c33
PB
2602 Compile the kernel with support for the retbleed=ibpb and
2603 spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
f43b9876 2604
1da8d217 2605config MITIGATION_IBRS_ENTRY
f43b9876 2606 bool "Enable IBRS on kernel entry"
b648ab48 2607 depends on CPU_SUP_INTEL && X86_64
f43b9876
PZ
2608 default y
2609 help
2610 Compile the kernel with support for the spectre_v2=ibrs mitigation.
2611 This mitigates both spectre_v2 and retbleed at great cost to
2612 performance.
2613
a033eec9 2614config MITIGATION_SRSO
fb3bd914 2615 bool "Mitigate speculative RAS overflow on AMD"
0911b8c5 2616 depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
fb3bd914
BPA
2617 default y
2618 help
2619 Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2620
7b75782f 2621config MITIGATION_SLS
f43b9876
PZ
2622 bool "Mitigate Straight-Line-Speculation"
2623 depends on CC_HAS_SLS && X86_64
2624 select OBJTOOL if HAVE_OBJTOOL
2625 default n
2626 help
2627 Compile the kernel with straight-line-speculation options to guard
2628 against straight line speculation. The kernel image might be slightly
2629 larger.
2630
225f2bd0
BL
2631config MITIGATION_GDS
2632 bool "Mitigate Gather Data Sampling"
2633 depends on CPU_SUP_INTEL
2634 default y
2635 help
2636 Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2637 vulnerability which allows unprivileged speculative access to data
2638 which was previously stored in vector registers. The attacker uses gather
2639 instructions to infer the stale vector register data.
2640
8076fcde
PG
2641config MITIGATION_RFDS
2642 bool "RFDS Mitigation"
2643 depends on CPU_SUP_INTEL
2644 default y
2645 help
2646 Enable mitigation for Register File Data Sampling (RFDS) by default.
2647 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2648 allows unprivileged speculative access to stale data previously
2649 stored in floating point, vector and integer registers.
2650 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2651
4f511739
JP
2652config MITIGATION_SPECTRE_BHI
2653 bool "Mitigate Spectre-BHB (Branch History Injection)"
ec9404e4 2654 depends on CPU_SUP_INTEL
4f511739 2655 default y
ec9404e4
PG
2656 help
2657 Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2658 where the branch history buffer is poisoned to speculatively steer
2659 indirect branches.
2660 See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2661
94045568
BL
2662config MITIGATION_MDS
2663 bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2664 depends on CPU_SUP_INTEL
2665 default y
2666 help
2667 Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2668 a hardware vulnerability which allows unprivileged speculative access
2669 to data which is available in various CPU internal buffers.
2670 See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
b8da0b33
BL
2671
2672config MITIGATION_TAA
2673 bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2674 depends on CPU_SUP_INTEL
2675 default y
2676 help
2677 Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2678 vulnerability that allows unprivileged speculative access to data
2679 which is available in various CPU internal buffers by using
2680 asynchronous aborts within an Intel TSX transactional region.
2681 See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
163f9fe6
BL
2682
2683config MITIGATION_MMIO_STALE_DATA
2684 bool "Mitigate MMIO Stale Data hardware bug"
2685 depends on CPU_SUP_INTEL
2686 default y
2687 help
2688 Enable mitigation for MMIO Stale Data hardware bugs. Processor MMIO
2689 Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2690 vulnerabilities that can expose data. The vulnerabilities require the
2691 attacker to have access to MMIO.
2692 See also
2693 <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
3a4ee4ff
BL
2694
2695config MITIGATION_L1TF
2696 bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2697 depends on CPU_SUP_INTEL
2698 default y
2699 help
2700 Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2701 hardware vulnerability which allows unprivileged speculative access to data
2702 available in the Level 1 Data Cache.
2703 See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
894e2885
BL
2704
2705config MITIGATION_RETBLEED
2706 bool "Mitigate RETBleed hardware bug"
2707 depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2708 default y
2709 help
2710 Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2711 with Return Instructions) vulnerability. RETBleed is a speculative
2712 execution attack which takes advantage of microarchitectural behavior
2713 in many modern microprocessors, similar to Spectre v2. An
2714 unprivileged attacker can use these flaws to bypass conventional
2715 memory security restrictions to gain read access to privileged memory
2716 that would otherwise be inaccessible.
ca01c0d8
BL
2717
2718config MITIGATION_SPECTRE_V1
2719 bool "Mitigate SPECTRE V1 hardware bug"
2720 default y
2721 help
2722 Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2723 class of side channel attacks that takes advantage of speculative
2724 execution that bypasses conditional branch instructions used for
2725 memory access bounds check.
2726 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
a0b02e3f 2727
72c70f48
BL
2728config MITIGATION_SPECTRE_V2
2729 bool "Mitigate SPECTRE V2 hardware bug"
2730 default y
2731 help
2732 Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2733 V2 is a class of side channel attacks that takes advantage of
2734 indirect branch predictors inside the processor. In Spectre variant 2
2735 attacks, the attacker can steer speculative indirect branches in the
2736 victim to gadget code by poisoning the branch target buffer of a CPU
2737 used for predicting indirect branch addresses.
2738 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2739
a0b02e3f
BL
2740config MITIGATION_SRBDS
2741 bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2742 depends on CPU_SUP_INTEL
2743 default y
2744 help
2745 Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2746 SRBDS is a hardware vulnerability that allows Microarchitectural Data
2747 Sampling (MDS) techniques to infer values returned from special
2748 register accesses. An unprivileged user can extract values returned
2749 from RDRAND and RDSEED executed on another core or sibling thread
2750 using MDS techniques.
2751 See also
2752 <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
b908cdab
BL
2753
2754config MITIGATION_SSB
2755 bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2756 default y
2757 help
2758 Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2759 hardware security vulnerability and its exploitation takes advantage
2760 of speculative execution in a similar way to the Meltdown and Spectre
2761 security vulnerabilities.
2762
f43b9876
PZ
2763endif
2764
3072e413
MH
2765config ARCH_HAS_ADD_PAGES
2766 def_bool y
5c11f00b 2767 depends on ARCH_ENABLE_MEMORY_HOTPLUG
3072e413 2768
da85f865 2769menu "Power management and ACPI options"
e279b6c1
SR
2770
2771config ARCH_HIBERNATION_HEADER
3c2362e6 2772 def_bool y
44556530 2773 depends on HIBERNATION
e279b6c1
SR
2774
2775source "kernel/power/Kconfig"
2776
2777source "drivers/acpi/Kconfig"
2778
a6b68076 2779config X86_APM_BOOT
6fc108a0 2780 def_bool y
282e5aab 2781 depends on APM
a6b68076 2782
e279b6c1
SR
2783menuconfig APM
2784 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2785 depends on X86_32 && PM_SLEEP
a7f7f624 2786 help
e279b6c1
SR
2787 APM is a BIOS specification for saving power using several different
2788 techniques. This is mostly useful for battery powered laptops with
2789 APM compliant BIOSes. If you say Y here, the system time will be
2790 reset after a RESUME operation, the /proc/apm device will provide
2791 battery status information, and user-space programs will receive
2792 notification of APM "events" (e.g. battery status change).
2793
2794 If you select "Y" here, you can disable actual use of the APM
2795 BIOS by passing the "apm=off" option to the kernel at boot time.
2796
2797 Note that the APM support is almost completely disabled for
2798 machines with more than one CPU.
2799
2800 In order to use APM, you will need supporting software. For location
151f4e2b 2801 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2802 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2803 <http://www.tldp.org/docs.html#howto>.
2804
2805 This driver does not spin down disk drives (see the hdparm(8)
2806 manpage ("man 8 hdparm") for that), and it doesn't turn off
2807 VESA-compliant "green" monitors.
2808
2809 This driver does not support the TI 4000M TravelMate and the ACER
2810 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2811 desktop machines also don't have compliant BIOSes, and this driver
2812 may cause those machines to panic during the boot phase.
2813
2814 Generally, if you don't have a battery in your machine, there isn't
2815 much point in using this driver and you should say N. If you get
2816 random kernel OOPSes or reboots that don't seem to be related to
2817 anything, try disabling/enabling this option (or disabling/enabling
2818 APM in your BIOS).
2819
2820 Some other things you should try when experiencing seemingly random,
2821 "weird" problems:
2822
2823 1) make sure that you have enough swap space and that it is
2824 enabled.
7987448f 2825 2) pass the "idle=poll" option to the kernel
e279b6c1
SR
2826 3) switch on floating point emulation in the kernel and pass
2827 the "no387" option to the kernel
2828 4) pass the "floppy=nodma" option to the kernel
2829 5) pass the "mem=4M" option to the kernel (thereby disabling
2830 all but the first 4 MB of RAM)
2831 6) make sure that the CPU is not over clocked.
2832 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2833 8) disable the cache from your BIOS settings
2834 9) install a fan for the video card or exchange video RAM
2835 10) install a better fan for the CPU
2836 11) exchange RAM chips
2837 12) exchange the motherboard.
2838
2839 To compile this driver as a module, choose M here: the
2840 module will be called apm.
2841
2842if APM
2843
2844config APM_IGNORE_USER_SUSPEND
2845 bool "Ignore USER SUSPEND"
a7f7f624 2846 help
e279b6c1
SR
2847 This option will ignore USER SUSPEND requests. On machines with a
2848 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2849 series notebooks, it is necessary to say Y because of a BIOS bug.
2850
2851config APM_DO_ENABLE
2852 bool "Enable PM at boot time"
a7f7f624 2853 help
e279b6c1
SR
2854 Enable APM features at boot time. From page 36 of the APM BIOS
2855 specification: "When disabled, the APM BIOS does not automatically
2856 power manage devices, enter the Standby State, enter the Suspend
2857 State, or take power saving steps in response to CPU Idle calls."
2858 This driver will make CPU Idle calls when Linux is idle (unless this
2859 feature is turned off -- see "Do CPU IDLE calls", below). This
2860 should always save battery power, but more complicated APM features
2861 will be dependent on your BIOS implementation. You may need to turn
2862 this option off if your computer hangs at boot time when using APM
2863 support, or if it beeps continuously instead of suspending. Turn
2864 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2865 T400CDT. This is off by default since most machines do fine without
2866 this feature.
2867
2868config APM_CPU_IDLE
dd8af076 2869 depends on CPU_IDLE
e279b6c1 2870 bool "Make CPU Idle calls when idle"
a7f7f624 2871 help
e279b6c1
SR
2872 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2873 On some machines, this can activate improved power savings, such as
2874 a slowed CPU clock rate, when the machine is idle. These idle calls
2875 are made after the idle loop has run for some length of time (e.g.,
2876 333 mS). On some machines, this will cause a hang at boot time or
2877 whenever the CPU becomes idle. (On machines with more than one CPU,
2878 this option does nothing.)
2879
2880config APM_DISPLAY_BLANK
2881 bool "Enable console blanking using APM"
a7f7f624 2882 help
e279b6c1
SR
2883 Enable console blanking using the APM. Some laptops can use this to
2884 turn off the LCD backlight when the screen blanker of the Linux
2885 virtual console blanks the screen. Note that this is only used by
2886 the virtual console screen blanker, and won't turn off the backlight
2887 when using the X Window system. This also doesn't have anything to
2888 do with your VESA-compliant power-saving monitor. Further, this
2889 option doesn't work for all laptops -- it might not turn off your
2890 backlight at all, or it might print a lot of errors to the console,
2891 especially if you are using gpm.
2892
2893config APM_ALLOW_INTS
2894 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2895 help
e279b6c1
SR
2896 Normally we disable external interrupts while we are making calls to
2897 the APM BIOS as a measure to lessen the effects of a badly behaving
2898 BIOS implementation. The BIOS should reenable interrupts if it
2899 needs to. Unfortunately, some BIOSes do not -- especially those in
2900 many of the newer IBM Thinkpads. If you experience hangs when you
2901 suspend, try setting this to Y. Otherwise, say N.
2902
e279b6c1
SR
2903endif # APM
2904
bb0a56ec 2905source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2906
2907source "drivers/cpuidle/Kconfig"
2908
27471fdb
AH
2909source "drivers/idle/Kconfig"
2910
e279b6c1
SR
2911endmenu
2912
e279b6c1
SR
2913menu "Bus options (PCI etc.)"
2914
e279b6c1
SR
2915choice
2916 prompt "PCI access mode"
efefa6f6 2917 depends on X86_32 && PCI
e279b6c1 2918 default PCI_GOANY
a7f7f624 2919 help
e279b6c1
SR
2920 On PCI systems, the BIOS can be used to detect the PCI devices and
2921 determine their configuration. However, some old PCI motherboards
2922 have BIOS bugs and may crash if this is done. Also, some embedded
2923 PCI-based systems don't have any BIOS at all. Linux can also try to
2924 detect the PCI hardware directly without using the BIOS.
2925
2926 With this option, you can specify how Linux should detect the
2927 PCI devices. If you choose "BIOS", the BIOS will be used,
2928 if you choose "Direct", the BIOS won't be used, and if you
2929 choose "MMConfig", then PCI Express MMCONFIG will be used.
2930 If you choose "Any", the kernel will try MMCONFIG, then the
2931 direct access method and falls back to the BIOS if that doesn't
2932 work. If unsure, go with the default, which is "Any".
2933
2934config PCI_GOBIOS
2935 bool "BIOS"
2936
2937config PCI_GOMMCONFIG
2938 bool "MMConfig"
2939
2940config PCI_GODIRECT
2941 bool "Direct"
2942
3ef0e1f8 2943config PCI_GOOLPC
76fb6570 2944 bool "OLPC XO-1"
3ef0e1f8
AS
2945 depends on OLPC
2946
2bdd1b03
AS
2947config PCI_GOANY
2948 bool "Any"
2949
e279b6c1
SR
2950endchoice
2951
2952config PCI_BIOS
3c2362e6 2953 def_bool y
efefa6f6 2954 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2955
2956# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2957config PCI_DIRECT
3c2362e6 2958 def_bool y
0aba496f 2959 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2960
2961config PCI_MMCONFIG
b45c9f36
JK
2962 bool "Support mmconfig PCI config space access" if X86_64
2963 default y
4590d98f 2964 depends on PCI && (ACPI || JAILHOUSE_GUEST)
b45c9f36 2965 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2966
3ef0e1f8 2967config PCI_OLPC
2bdd1b03
AS
2968 def_bool y
2969 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2970
b5401a96
AN
2971config PCI_XEN
2972 def_bool y
2973 depends on PCI && XEN
b5401a96 2974
8364e1f8
JK
2975config MMCONF_FAM10H
2976 def_bool y
2977 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2978
3f6ea84a 2979config PCI_CNB20LE_QUIRK
6a108a14 2980 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2981 depends on PCI
3f6ea84a
IS
2982 help
2983 Read the PCI windows out of the CNB20LE host bridge. This allows
2984 PCI hotplug to work on systems with the CNB20LE chipset which do
2985 not have ACPI.
2986
64a5fed6
BH
2987 There's no public spec for this chipset, and this functionality
2988 is known to be incomplete.
2989
2990 You should say N unless you know you need this.
2991
3a495511 2992config ISA_BUS
17a2a129 2993 bool "ISA bus support on modern systems" if EXPERT
3a495511 2994 help
17a2a129
WBG
2995 Expose ISA bus device drivers and options available for selection and
2996 configuration. Enable this option if your target machine has an ISA
2997 bus. ISA is an older system, displaced by PCI and newer bus
2998 architectures -- if your target machine is modern, it probably does
2999 not have an ISA bus.
3a495511
WBG
3000
3001 If unsure, say N.
3002
1c00f016 3003# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 3004config ISA_DMA_API
1c00f016
DR
3005 bool "ISA-style DMA support" if (X86_64 && EXPERT)
3006 default y
3007 help
3008 Enables ISA-style DMA support for devices requiring such controllers.
3009 If unsure, say Y.
e279b6c1 3010
51e68d05
LT
3011if X86_32
3012
e279b6c1
SR
3013config ISA
3014 bool "ISA support"
a7f7f624 3015 help
e279b6c1
SR
3016 Find out whether you have ISA slots on your motherboard. ISA is the
3017 name of a bus system, i.e. the way the CPU talks to the other stuff
3018 inside your box. Other bus systems are PCI, EISA, MicroChannel
3019 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
3020 newer boards don't support it. If you have ISA, say Y, otherwise N.
3021
e279b6c1
SR
3022config SCx200
3023 tristate "NatSemi SCx200 support"
a7f7f624 3024 help
e279b6c1
SR
3025 This provides basic support for National Semiconductor's
3026 (now AMD's) Geode processors. The driver probes for the
3027 PCI-IDs of several on-chip devices, so its a good dependency
3028 for other scx200_* drivers.
3029
3030 If compiled as a module, the driver is named scx200.
3031
3032config SCx200HR_TIMER
3033 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 3034 depends on SCx200
e279b6c1 3035 default y
a7f7f624 3036 help
e279b6c1
SR
3037 This driver provides a clocksource built upon the on-chip
3038 27MHz high-resolution timer. Its also a workaround for
3039 NSC Geode SC-1100's buggy TSC, which loses time when the
3040 processor goes idle (as is done by the scheduler). The
3041 other workaround is idle=poll boot option.
3042
3ef0e1f8
AS
3043config OLPC
3044 bool "One Laptop Per Child support"
54008979 3045 depends on !X86_PAE
3c554946 3046 select GPIOLIB
dc3119e7 3047 select OF
45bb1674 3048 select OF_PROMTREE
b4e51854 3049 select IRQ_DOMAIN
0c3d931b 3050 select OLPC_EC
a7f7f624 3051 help
3ef0e1f8
AS
3052 Add support for detecting the unique features of the OLPC
3053 XO hardware.
3054
a3128588
DD
3055config OLPC_XO1_PM
3056 bool "OLPC XO-1 Power Management"
fa112cf1 3057 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 3058 help
97c4cb71 3059 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 3060
cfee9597
DD
3061config OLPC_XO1_RTC
3062 bool "OLPC XO-1 Real Time Clock"
3063 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 3064 help
cfee9597
DD
3065 Add support for the XO-1 real time clock, which can be used as a
3066 programmable wakeup source.
3067
7feda8e9
DD
3068config OLPC_XO1_SCI
3069 bool "OLPC XO-1 SCI extras"
92e830f2 3070 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 3071 depends on INPUT=y
d8d01a63 3072 select POWER_SUPPLY
a7f7f624 3073 help
7feda8e9 3074 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 3075 - EC-driven system wakeups
7feda8e9 3076 - Power button
7bc74b3d 3077 - Ebook switch
2cf2baea 3078 - Lid switch
e1040ac6
DD
3079 - AC adapter status updates
3080 - Battery status updates
7feda8e9 3081
a0f30f59
DD
3082config OLPC_XO15_SCI
3083 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
3084 depends on OLPC && ACPI
3085 select POWER_SUPPLY
a7f7f624 3086 help
a0f30f59
DD
3087 Add support for SCI-based features of the OLPC XO-1.5 laptop:
3088 - EC-driven system wakeups
3089 - AC adapter status updates
3090 - Battery status updates
bf1ebf00 3091
298c9bab
DT
3092config GEODE_COMMON
3093 bool
3094
d4f3e350
EW
3095config ALIX
3096 bool "PCEngines ALIX System Support (LED setup)"
3097 select GPIOLIB
298c9bab 3098 select GEODE_COMMON
a7f7f624 3099 help
d4f3e350
EW
3100 This option enables system support for the PCEngines ALIX.
3101 At present this just sets up LEDs for GPIO control on
3102 ALIX2/3/6 boards. However, other system specific setup should
3103 get added here.
3104
3105 Note: You must still enable the drivers for GPIO and LED support
3106 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3107
3108 Note: You have to set alix.force=1 for boards with Award BIOS.
3109
da4e3302
PP
3110config NET5501
3111 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3112 select GPIOLIB
298c9bab 3113 select GEODE_COMMON
a7f7f624 3114 help
da4e3302
PP
3115 This option enables system support for the Soekris Engineering net5501.
3116
3197059a
PP
3117config GEOS
3118 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3119 select GPIOLIB
298c9bab 3120 select GEODE_COMMON
3197059a 3121 depends on DMI
a7f7f624 3122 help
3197059a
PP
3123 This option enables system support for the Traverse Technologies GEOS.
3124
7d029125
VD
3125config TS5500
3126 bool "Technologic Systems TS-5500 platform support"
3127 depends on MELAN
3128 select CHECK_SIGNATURE
3129 select NEW_LEDS
3130 select LEDS_CLASS
a7f7f624 3131 help
7d029125
VD
3132 This option enables system support for the Technologic Systems TS-5500.
3133
bc0120fd
SR
3134endif # X86_32
3135
23ac4ae8 3136config AMD_NB
e6e6e5e8
YG
3137 def_bool y
3138 depends on AMD_NODE
3139
3140config AMD_NODE
e279b6c1 3141 def_bool y
0e152cd7 3142 depends on CPU_SUP_AMD && PCI
e279b6c1 3143
e279b6c1
SR
3144endmenu
3145
1572497c 3146menu "Binary Emulations"
e279b6c1
SR
3147
3148config IA32_EMULATION
3149 bool "IA32 Emulation"
3150 depends on X86_64
39f88911 3151 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 3152 select BINFMT_ELF
39f88911 3153 select COMPAT_OLD_SIGACTION
a7f7f624 3154 help
5fd92e65
L
3155 Include code to run legacy 32-bit programs under a
3156 64-bit kernel. You should likely turn this on, unless you're
3157 100% sure that you don't have any 32-bit programs left.
e279b6c1 3158
a11e0975
NB
3159config IA32_EMULATION_DEFAULT_DISABLED
3160 bool "IA32 emulation disabled by default"
3161 default n
3162 depends on IA32_EMULATION
3163 help
3164 Make IA32 emulation disabled by default. This prevents loading 32-bit
3165 processes and access to 32-bit syscalls. If unsure, leave it to its
3166 default value.
3167
83a44a4f 3168config X86_X32_ABI
6ea30386 3169 bool "x32 ABI for 64-bit mode"
9b54050b 3170 depends on X86_64
aaeed6ec
NC
3171 # llvm-objcopy does not convert x86_64 .note.gnu.property or
3172 # compressed debug sections to x86_x32 properly:
3173 # https://github.com/ClangBuiltLinux/linux/issues/514
3174 # https://github.com/ClangBuiltLinux/linux/issues/1141
3175 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
a7f7f624 3176 help
5fd92e65
L
3177 Include code to run binaries for the x32 native 32-bit ABI
3178 for 64-bit processors. An x32 process gets access to the
3179 full 64-bit register file and wide data path while leaving
3180 pointers at 32 bits for smaller memory footprint.
3181
953fee1d
IM
3182config COMPAT_32
3183 def_bool y
3184 depends on IA32_EMULATION || X86_32
3185 select HAVE_UID16
3186 select OLD_SIGSUSPEND3
3187
e279b6c1 3188config COMPAT
3c2362e6 3189 def_bool y
83a44a4f 3190 depends on IA32_EMULATION || X86_X32_ABI
e279b6c1
SR
3191
3192config COMPAT_FOR_U64_ALIGNMENT
3120e25e 3193 def_bool y
a9251280 3194 depends on COMPAT
ee009e4a 3195
e279b6c1
SR
3196endmenu
3197
e5beae16
KP
3198config HAVE_ATOMIC_IOMAP
3199 def_bool y
3200 depends on X86_32
3201
edf88417 3202source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
3203
3204source "arch/x86/Kconfig.assembler"
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