]> git.ipfire.org Git - thirdparty/kernel/stable.git/blame - arch/x86/Kconfig
treewide: remove CONFIG_HAVE_KVM
[thirdparty/kernel/stable.git] / arch / x86 / Kconfig
CommitLineData
b2441318 1# SPDX-License-Identifier: GPL-2.0
daa93fab
SR
2# Select 32 or 64 bit
3config 64BIT
104daea1
MY
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
a7f7f624 6 help
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
3120e25e
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
d94e0685
IM
31 select HAVE_ARCH_SOFT_DIRTY
32 select MODULES_USE_ELF_RELA
f616ab59 33 select NEED_DMA_MAP_STATE
09230cbc 34 select SWIOTLB
7facdc42 35 select ARCH_HAS_ELFCORE_COMPAT
63703f37 36 select ZONE_DMA32
1032c0ba 37
518049d9
SRV
38config FORCE_DYNAMIC_FTRACE
39 def_bool y
40 depends on X86_32
41 depends on FUNCTION_TRACER
42 select DYNAMIC_FTRACE
43 help
758cd94a
JH
44 We keep the static function tracing (!DYNAMIC_FTRACE) around
45 in order to test the non static function tracing in the
46 generic code, as other architectures still use it. But we
47 only need to keep it around for x86_64. No need to keep it
48 for x86_32. For x86_32, force DYNAMIC_FTRACE.
d94e0685
IM
49#
50# Arch settings
51#
52# ( Note that options that are marked 'if X86_64' could in principle be
53# ported to 32-bit as well. )
54#
8d5fffb9 55config X86
3c2362e6 56 def_bool y
c763ea26
IM
57 #
58 # Note: keep this list sorted alphabetically
59 #
6471b825
IM
60 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
61 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
a02f66bb 62 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU
942fa985 63 select ARCH_32BIT_OFF_T if X86_32
2a21ad57 64 select ARCH_CLOCKSOURCE_INIT
1f6d3a8f 65 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
1e866974 66 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
5c11f00b 67 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
91024b3c 68 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
cebc774f 69 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
1e866974 70 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
c763ea26 71 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
c2280be8 72 select ARCH_HAS_CACHE_LINE_SIZE
1156b441 73 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
7c7077a7 74 select ARCH_HAS_CPU_FINALIZE_INIT
8f23f5db 75 select ARCH_HAS_CPU_PASID if IOMMU_SVA
2792d84e 76 select ARCH_HAS_CURRENT_STACK_POINTER
fa5b6ec9 77 select ARCH_HAS_DEBUG_VIRTUAL
399145f9 78 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
21266be9 79 select ARCH_HAS_DEVMEM_IS_ALLOWED
b1a57bbf 80 select ARCH_HAS_EARLY_DEBUG if KGDB
6471b825 81 select ARCH_HAS_ELF_RANDOMIZE
72d93104 82 select ARCH_HAS_FAST_MULTIPLIER
6974f0c4 83 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 84 select ARCH_HAS_GCOV_PROFILE_ALL
bece04b5 85 select ARCH_HAS_KCOV if X86_64
0c9c1d56 86 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 87 select ARCH_HAS_MEMBARRIER_SYNC_CORE
49f88c70 88 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
0ebeea8c 89 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
c763ea26 90 select ARCH_HAS_PMEM_API if X86_64
17596731 91 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 92 select ARCH_HAS_PTE_SPECIAL
71ce1ab5 93 select ARCH_HAS_HW_PTE_YOUNG
eed9a328 94 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2
0aed55af 95 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
ec6347bb 96 select ARCH_HAS_COPY_MC if X86_64
d2852a22 97 select ARCH_HAS_SET_MEMORY
d253ca0c 98 select ARCH_HAS_SET_DIRECT_MAP
ad21fc4f
LA
99 select ARCH_HAS_STRICT_KERNEL_RWX
100 select ARCH_HAS_STRICT_MODULE_RWX
ac1ab12a 101 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
25c619e5 102 select ARCH_HAS_SYSCALL_WRAPPER
c6d30853 103 select ARCH_HAS_UBSAN_SANITIZE_ALL
7e01ccb4 104 select ARCH_HAS_DEBUG_WX
63703f37 105 select ARCH_HAS_ZONE_DMA_SET if EXPERT
6471b825 106 select ARCH_HAVE_NMI_SAFE_CMPXCHG
04d5ea46 107 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
6471b825 108 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 109 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 110 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 111 select ARCH_STACKWALK
2c870e61 112 select ARCH_SUPPORTS_ACPI
6471b825 113 select ARCH_SUPPORTS_ATOMIC_RMW
5d6ad668 114 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
d283d422 115 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64
6471b825 116 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
14df3267 117 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096
3c516f89
ST
118 select ARCH_SUPPORTS_CFI_CLANG if X86_64
119 select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG
583bfd48
NC
120 select ARCH_SUPPORTS_LTO_CLANG
121 select ARCH_SUPPORTS_LTO_CLANG_THIN
6471b825 122 select ARCH_USE_BUILTIN_BSWAP
a432b7c0 123 select ARCH_USE_CMPXCHG_LOCKREF if X86_CMPXCHG64
dce44566 124 select ARCH_USE_MEMTEST
6471b825
IM
125 select ARCH_USE_QUEUED_RWLOCKS
126 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 127 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 128 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 129 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 130 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
51c2ee6d 131 select ARCH_WANTS_NO_INSTR
07431506 132 select ARCH_WANT_GENERAL_HUGETLB
3876d4a3 133 select ARCH_WANT_HUGE_PMD_SHARE
59612b24 134 select ARCH_WANT_LD_ORPHAN_WARN
0b6f1582
AK
135 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64
136 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64
38d8b4e6 137 select ARCH_WANTS_THP_SWAP if X86_64
b5f06f64 138 select ARCH_HAS_PARANOID_L1D_FLUSH
10916706 139 select BUILDTIME_TABLE_SORT
6471b825 140 select CLKEVT_I8253
6471b825
IM
141 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
142 select CLOCKSOURCE_WATCHDOG
7cf8f44a
AP
143 # Word-size accesses may read uninitialized data past the trailing \0
144 # in strings and cause false KMSAN reports.
145 select DCACHE_WORD_ACCESS if !KMSAN
3aac3ebe 146 select DYNAMIC_SIGFRAME
45471cd9
LT
147 select EDAC_ATOMIC_SCRUB
148 select EDAC_SUPPORT
6471b825
IM
149 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
150 select GENERIC_CLOCKEVENTS_MIN_ADJUST
151 select GENERIC_CMOS_UPDATE
152 select GENERIC_CPU_AUTOPROBE
5b95f94c 153 select GENERIC_CPU_DEVICES
61dc0f55 154 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 155 select GENERIC_EARLY_IOREMAP
27d6b4d1 156 select GENERIC_ENTRY
6471b825 157 select GENERIC_IOMAP
c7d6c9dd 158 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 159 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 160 select GENERIC_IRQ_MIGRATION if SMP
6471b825 161 select GENERIC_IRQ_PROBE
c201c917 162 select GENERIC_IRQ_RESERVATION_MODE
6471b825
IM
163 select GENERIC_IRQ_SHOW
164 select GENERIC_PENDING_IRQ if SMP
2ae27137 165 select GENERIC_PTDUMP
6471b825 166 select GENERIC_SMP_IDLE_THREAD
6471b825 167 select GENERIC_TIME_VSYSCALL
7ac87074 168 select GENERIC_GETTIMEOFDAY
550a77a7 169 select GENERIC_VDSO_TIME_NS
6ca297d4 170 select GUP_GET_PXX_LOW_HIGH if X86_PAE
17e5888e 171 select HARDIRQS_SW_RESEND
7edaeb68 172 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
fcbfe812 173 select HAS_IOPORT
6471b825
IM
174 select HAVE_ACPI_APEI if ACPI
175 select HAVE_ACPI_APEI_NMI if ACPI
2a19be61 176 select HAVE_ALIGNED_STRUCT_PAGE
6471b825
IM
177 select HAVE_ARCH_AUDITSYSCALL
178 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
eed1fcee 179 select HAVE_ARCH_HUGE_VMALLOC if X86_64
6471b825 180 select HAVE_ARCH_JUMP_LABEL
b34006c4 181 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 182 select HAVE_ARCH_KASAN if X86_64
0609ae01 183 select HAVE_ARCH_KASAN_VMALLOC if X86_64
1dc0da6e 184 select HAVE_ARCH_KFENCE
4ca8cc8d 185 select HAVE_ARCH_KMSAN if X86_64
6471b825 186 select HAVE_ARCH_KGDB
9e08f57d
DC
187 select HAVE_ARCH_MMAP_RND_BITS if MMU
188 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 189 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 190 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 191 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 192 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 193 select HAVE_ARCH_STACKLEAK
6471b825
IM
194 select HAVE_ARCH_TRACEHOOK
195 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 196 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 197 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
7677f7fd 198 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD
e37e43a4 199 select HAVE_ARCH_VMAP_STACK if X86_64
fe950f60 200 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
c763ea26 201 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 202 select HAVE_ASM_MODVERSIONS
6471b825
IM
203 select HAVE_CMPXCHG_DOUBLE
204 select HAVE_CMPXCHG_LOCAL
24a9c541
FW
205 select HAVE_CONTEXT_TRACKING_USER if X86_64
206 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER
cf4db259 207 select HAVE_C_RECORDMCOUNT
03f16cd0 208 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL
280981d6 209 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT
4ed308c4 210 select HAVE_BUILDTIME_MCOUNT_SORT
6471b825 211 select HAVE_DEBUG_KMEMLEAK
6471b825 212 select HAVE_DMA_CONTIGUOUS
677aa9f7 213 select HAVE_DYNAMIC_FTRACE
06aeaaea 214 select HAVE_DYNAMIC_FTRACE_WITH_REGS
02a474ca 215 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64
562955fe 216 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
c316eb44 217 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64
503e4510 218 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64
03f5781b 219 select HAVE_EBPF_JIT
58340a07 220 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 221 select HAVE_EISA
5f56a5df 222 select HAVE_EXIT_THREAD
67a929e0 223 select HAVE_FAST_GUP
644e0e8d 224 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 225 select HAVE_FTRACE_MCOUNT_RECORD
d938ba17 226 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
4a30e4c9 227 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE)
6471b825 228 select HAVE_FUNCTION_TRACER
6b90bd4b 229 select HAVE_GCC_PLUGINS
6471b825 230 select HAVE_HW_BREAKPOINT
6471b825 231 select HAVE_IOREMAP_PROT
624db9ea 232 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
6471b825 233 select HAVE_IRQ_TIME_ACCOUNTING
4ab7674f 234 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL
2e9f3bdd 235 select HAVE_KERNEL_BZIP2
6471b825
IM
236 select HAVE_KERNEL_GZIP
237 select HAVE_KERNEL_LZ4
2e9f3bdd 238 select HAVE_KERNEL_LZMA
13510997 239 select HAVE_KERNEL_LZO
6471b825 240 select HAVE_KERNEL_XZ
fb46d057 241 select HAVE_KERNEL_ZSTD
6471b825
IM
242 select HAVE_KPROBES
243 select HAVE_KPROBES_ON_FTRACE
540adea3 244 select HAVE_FUNCTION_ERROR_INJECTION
6471b825 245 select HAVE_KRETPROBES
f3a112c0 246 select HAVE_RETHOOK
6471b825 247 select HAVE_LIVEPATCH if X86_64
0102752e 248 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 249 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 250 select HAVE_MOVE_PMD
be37c98d 251 select HAVE_MOVE_PUD
22102f45 252 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL
42a0bb3f 253 select HAVE_NMI
489e355b 254 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL
03f16cd0 255 select HAVE_OBJTOOL if X86_64
6471b825
IM
256 select HAVE_OPTPROBES
257 select HAVE_PCSPKR_PLATFORM
258 select HAVE_PERF_EVENTS
c01d4323 259 select HAVE_PERF_EVENTS_NMI
92e5aae4 260 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 261 select HAVE_PCI
c5e63197 262 select HAVE_PERF_REGS
c5ebcedb 263 select HAVE_PERF_USER_STACK_DUMP
03f16cd0 264 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
1e9fdf21 265 select MMU_GATHER_MERGE_VMAS
00998085 266 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 267 select HAVE_REGS_AND_STACK_ACCESS_API
03f16cd0 268 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION
3c88ee19 269 select HAVE_FUNCTION_ARG_ACCESS_API
7ecd19cf 270 select HAVE_SETUP_PER_CPU_AREA
cd1a41ce 271 select HAVE_SOFTIRQ_ON_OWN_STACK
d148eac0 272 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
03f16cd0 273 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL
e6d6c071 274 select HAVE_STATIC_CALL
03f16cd0 275 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL
99cf983c 276 select HAVE_PREEMPT_DYNAMIC_CALL
d6761b8f 277 select HAVE_RSEQ
09498135 278 select HAVE_RUST if X86_64
6471b825 279 select HAVE_SYSCALL_TRACEPOINTS
5f3da8c0 280 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL
6471b825 281 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 282 select HAVE_USER_RETURN_NOTIFIER
7ac87074 283 select HAVE_GENERIC_VDSO
0c7ffa32 284 select HOTPLUG_PARALLEL if SMP && X86_64
05736e4a 285 select HOTPLUG_SMT if SMP
0c7ffa32 286 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32
c0185808 287 select IRQ_FORCED_THREADING
c2508ec5 288 select LOCK_MM_AND_FIND_VMA
7ecd19cf
KW
289 select NEED_PER_CPU_EMBED_FIRST_CHUNK
290 select NEED_PER_CPU_PAGE_FIRST_CHUNK
86596f0a 291 select NEED_SG_DMA_LENGTH
2eac9c2d 292 select PCI_DOMAINS if PCI
625210cf 293 select PCI_LOCKLESS_CONFIG if PCI
6471b825 294 select PERF_EVENTS
3195ef59 295 select RTC_LIB
d6faca40 296 select RTC_MC146818_LIB
6471b825 297 select SPARSE_IRQ
6471b825 298 select SYSCTL_EXCEPTION_TRACE
15f4eae7 299 select THREAD_INFO_IN_TASK
4aae683f 300 select TRACE_IRQFLAGS_SUPPORT
4510bffb 301 select TRACE_IRQFLAGS_NMI_SUPPORT
6471b825 302 select USER_STACKTRACE_SUPPORT
3b02a051 303 select HAVE_ARCH_KCSAN if X86_64
0c608dad 304 select PROC_PID_ARCH_STATUS if PROC_FS
50468e43 305 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX
d49a0626
PZ
306 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16
307 select FUNCTION_ALIGNMENT_4B
9e2b4be3 308 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
ceea991a 309 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
7d8330a5 310
ba7e4d13 311config INSTRUCTION_DECODER
3120e25e
JB
312 def_bool y
313 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 314
51b26ada
LT
315config OUTPUT_FORMAT
316 string
317 default "elf32-i386" if X86_32
318 default "elf64-x86-64" if X86_64
319
8d5fffb9 320config LOCKDEP_SUPPORT
3c2362e6 321 def_bool y
8d5fffb9
SR
322
323config STACKTRACE_SUPPORT
3c2362e6 324 def_bool y
8d5fffb9 325
8d5fffb9 326config MMU
3c2362e6 327 def_bool y
8d5fffb9 328
9e08f57d
DC
329config ARCH_MMAP_RND_BITS_MIN
330 default 28 if 64BIT
331 default 8
332
333config ARCH_MMAP_RND_BITS_MAX
334 default 32 if 64BIT
335 default 16
336
337config ARCH_MMAP_RND_COMPAT_BITS_MIN
338 default 8
339
340config ARCH_MMAP_RND_COMPAT_BITS_MAX
341 default 16
342
8d5fffb9
SR
343config SBUS
344 bool
345
346config GENERIC_ISA_DMA
3120e25e
JB
347 def_bool y
348 depends on ISA_DMA_API
8d5fffb9 349
d911c67e
AP
350config GENERIC_CSUM
351 bool
352 default y if KMSAN || KASAN
353
8d5fffb9 354config GENERIC_BUG
3c2362e6 355 def_bool y
8d5fffb9 356 depends on BUG
b93a531e
JB
357 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
358
359config GENERIC_BUG_RELATIVE_POINTERS
360 bool
8d5fffb9 361
8d5fffb9 362config ARCH_MAY_HAVE_PC_FDC
3120e25e
JB
363 def_bool y
364 depends on ISA_DMA_API
8d5fffb9 365
1032c0ba
SR
366config GENERIC_CALIBRATE_DELAY
367 def_bool y
368
9a0b8415 369config ARCH_HAS_CPU_RELAX
370 def_bool y
371
801e4062
JB
372config ARCH_HIBERNATION_POSSIBLE
373 def_bool y
801e4062 374
f4cb5700
JB
375config ARCH_SUSPEND_POSSIBLE
376 def_bool y
f4cb5700 377
8d5fffb9 378config AUDIT_ARCH
e0fd24a3 379 def_bool y if X86_64
8d5fffb9 380
d6f2d75a
AR
381config KASAN_SHADOW_OFFSET
382 hex
383 depends on KASAN
384 default 0xdffffc0000000000
385
69575d38
SW
386config HAVE_INTEL_TXT
387 def_bool y
6ea30386 388 depends on INTEL_IOMMU && ACPI
69575d38 389
6b0c3d44
SR
390config X86_64_SMP
391 def_bool y
392 depends on X86_64 && SMP
393
2b144498
SD
394config ARCH_SUPPORTS_UPROBES
395 def_bool y
396
d20642f0
RH
397config FIX_EARLYCON_MEM
398 def_bool y
399
94d49eb3
KS
400config DYNAMIC_PHYSICAL_MASK
401 bool
402
98233368
KS
403config PGTABLE_LEVELS
404 int
77ef56e4 405 default 5 if X86_5LEVEL
98233368
KS
406 default 4 if X86_64
407 default 3 if X86_PAE
408 default 2
409
2a61f474
MY
410config CC_HAS_SANE_STACKPROTECTOR
411 bool
1b866781
NC
412 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
413 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
2a61f474 414 help
758cd94a
JH
415 We have to make sure stack protector is unconditionally disabled if
416 the compiler produces broken code or if it does not let us control
417 the segment on 32-bit kernels.
2a61f474 418
506f1d07
SR
419menu "Processor type and features"
420
506f1d07
SR
421config SMP
422 bool "Symmetric multi-processing support"
a7f7f624 423 help
506f1d07 424 This enables support for systems with more than one CPU. If you have
4a474157
RG
425 a system with only one CPU, say N. If you have a system with more
426 than one CPU, say Y.
506f1d07 427
4a474157 428 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
429 machines, but will use only one CPU of a multiprocessor machine. If
430 you say Y here, the kernel will run on many, but not all,
4a474157 431 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
432 will run faster if you say N here.
433
434 Note that if you say Y here and choose architecture "586" or
435 "Pentium" under "Processor family", the kernel will not work on 486
436 architectures. Similarly, multiprocessor kernels for the "PPro"
437 architecture may not work on all Pentium based boards.
438
439 People using multiprocessor machines who say Y here should also say
440 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
441 Management" code will be disabled if you say Y here.
442
ff61f079 443 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
4f4cfa6c 444 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
445 <http://www.tldp.org/docs.html#howto>.
446
447 If you don't know what to do here, say N.
448
06cd9a7d
YL
449config X86_X2APIC
450 bool "Support x2apic"
19e3d60d 451 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 452 help
06cd9a7d
YL
453 This enables x2apic support on CPUs that have this feature.
454
455 This allows 32-bit apic IDs (so it can support very large systems),
456 and accesses the local apic via MSRs not via mmio.
457
b8d1d163
DS
458 Some Intel systems circa 2022 and later are locked into x2APIC mode
459 and can not fall back to the legacy APIC modes if SGX or TDX are
e3998434
MJ
460 enabled in the BIOS. They will boot with very reduced functionality
461 without enabling this option.
b8d1d163 462
06cd9a7d
YL
463 If you don't know what to do here, say N.
464
6695c85b 465config X86_MPPARSE
4590d98f 466 bool "Enable MPS table" if ACPI
7a527688 467 default y
5ab74722 468 depends on X86_LOCAL_APIC
a7f7f624 469 help
6695c85b
YL
470 For old smp systems that do not have proper acpi support. Newer systems
471 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 472
ddd70cf9 473config GOLDFISH
b03b016f
KK
474 def_bool y
475 depends on X86_GOLDFISH
ddd70cf9 476
e6d42931
JW
477config X86_CPU_RESCTRL
478 bool "x86 CPU resource control support"
6fe07ce3 479 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 480 select KERNFS
e79f15a4 481 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 482 help
e6d42931 483 Enable x86 CPU resource control support.
6fe07ce3
BM
484
485 Provide support for the allocation and monitoring of system resources
486 usage by the CPU.
487
488 Intel calls this Intel Resource Director Technology
489 (Intel(R) RDT). More information about RDT can be found in the
490 Intel x86 Architecture Software Developer Manual.
491
492 AMD calls this AMD Platform Quality of Service (AMD QoS).
493 More information about AMD QoS can be found in the AMD64 Technology
494 Platform Quality of Service Extensions manual.
78e99b4a
FY
495
496 Say N if unsure.
497
8425091f 498if X86_32
a0d0bb4d
RD
499config X86_BIGSMP
500 bool "Support for big SMP systems with more than 8 CPUs"
501 depends on SMP
a7f7f624 502 help
e133f6ea 503 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 504
c5c606d9
RT
505config X86_EXTENDED_PLATFORM
506 bool "Support for extended (non-PC) x86 platforms"
507 default y
a7f7f624 508 help
06ac8346
IM
509 If you disable this option then the kernel will only support
510 standard PC platforms. (which covers the vast majority of
511 systems out there.)
512
8425091f
RT
513 If you enable this option then you'll be able to select support
514 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 515 Goldfish (Android emulator)
8425091f 516 AMD Elan
8425091f
RT
517 RDC R-321x SoC
518 SGI 320/540 (Visual Workstation)
83125a3a 519 STA2X11-based (e.g. Northville)
3f4110a4 520 Moorestown MID devices
06ac8346
IM
521
522 If you have one of these systems, or if you want to build a
523 generic distribution kernel, say Y here - otherwise say N.
758cd94a 524endif # X86_32
06ac8346 525
8425091f
RT
526if X86_64
527config X86_EXTENDED_PLATFORM
528 bool "Support for extended (non-PC) x86 platforms"
529 default y
a7f7f624 530 help
8425091f
RT
531 If you disable this option then the kernel will only support
532 standard PC platforms. (which covers the vast majority of
533 systems out there.)
534
535 If you enable this option then you'll be able to select support
536 for the following (non-PC) 64 bit x86 platforms:
44b111b5 537 Numascale NumaChip
8425091f
RT
538 ScaleMP vSMP
539 SGI Ultraviolet
540
541 If you have one of these systems, or if you want to build a
542 generic distribution kernel, say Y here - otherwise say N.
758cd94a 543endif # X86_64
c5c606d9
RT
544# This is an alphabetically sorted list of 64 bit extended platforms
545# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
546config X86_NUMACHIP
547 bool "Numascale NumaChip"
548 depends on X86_64
549 depends on X86_EXTENDED_PLATFORM
550 depends on NUMA
551 depends on SMP
552 depends on X86_X2APIC
f9726bfd 553 depends on PCI_MMCONFIG
a7f7f624 554 help
44b111b5
SP
555 Adds support for Numascale NumaChip large-SMP systems. Needed to
556 enable more than ~168 cores.
557 If you don't have one of these, you should say N here.
506f1d07 558
c5c606d9
RT
559config X86_VSMP
560 bool "ScaleMP vSMP"
6276a074 561 select HYPERVISOR_GUEST
c5c606d9
RT
562 select PARAVIRT
563 depends on X86_64 && PCI
564 depends on X86_EXTENDED_PLATFORM
ead91d4b 565 depends on SMP
a7f7f624 566 help
c5c606d9
RT
567 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
568 supposed to run on these EM64T-based machines. Only choose this option
569 if you have one of these machines.
5e3a77e9 570
03b48632
NP
571config X86_UV
572 bool "SGI Ultraviolet"
573 depends on X86_64
c5c606d9 574 depends on X86_EXTENDED_PLATFORM
54c28d29 575 depends on NUMA
1ecb4ae5 576 depends on EFI
c2209ea5 577 depends on KEXEC_CORE
9d6c26e7 578 depends on X86_X2APIC
1222e564 579 depends on PCI
a7f7f624 580 help
03b48632
NP
581 This option is needed in order to support SGI Ultraviolet systems.
582 If you don't have one of these, you should say N here.
583
c5c606d9
RT
584# Following is an alphabetically sorted list of 32 bit extended platforms
585# Please maintain the alphabetic order if and when there are additions
506f1d07 586
ddd70cf9 587config X86_GOLDFISH
b03b016f
KK
588 bool "Goldfish (Virtual Platform)"
589 depends on X86_EXTENDED_PLATFORM
a7f7f624 590 help
758cd94a
JH
591 Enable support for the Goldfish virtual platform used primarily
592 for Android development. Unless you are building for the Android
593 Goldfish emulator say N here.
ddd70cf9 594
c751e17b
TG
595config X86_INTEL_CE
596 bool "CE4100 TV platform"
597 depends on PCI
598 depends on PCI_GODIRECT
6084a6e2 599 depends on X86_IO_APIC
c751e17b
TG
600 depends on X86_32
601 depends on X86_EXTENDED_PLATFORM
37bc9f50 602 select X86_REBOOTFIXUPS
da6b737b
SAS
603 select OF
604 select OF_EARLY_FLATTREE
a7f7f624 605 help
c751e17b
TG
606 Select for the Intel CE media processor (CE4100) SOC.
607 This option compiles in support for the CE4100 SOC for settop
608 boxes and media devices.
609
4cb9b00f 610config X86_INTEL_MID
43605ef1 611 bool "Intel MID platform support"
43605ef1 612 depends on X86_EXTENDED_PLATFORM
edc6bc78 613 depends on X86_PLATFORM_DEVICES
1ea7c673 614 depends on PCI
3fda5bb4 615 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 616 depends on X86_IO_APIC
4cb9b00f 617 select I2C
7c9c3a1e 618 select DW_APB_TIMER
54b34aa0 619 select INTEL_SCU_PCI
a7f7f624 620 help
4cb9b00f
DC
621 Select to build a kernel capable of supporting Intel MID (Mobile
622 Internet Device) platform systems which do not have the PCI legacy
623 interfaces. If you are building for a PC class system say N here.
1ea7c673 624
4cb9b00f
DC
625 Intel MID platforms are based on an Intel processor and chipset which
626 consume less power than most of the x86 derivatives.
43605ef1 627
8bbc2a13
BD
628config X86_INTEL_QUARK
629 bool "Intel Quark platform support"
630 depends on X86_32
631 depends on X86_EXTENDED_PLATFORM
632 depends on X86_PLATFORM_DEVICES
633 depends on X86_TSC
634 depends on PCI
635 depends on PCI_GOANY
636 depends on X86_IO_APIC
637 select IOSF_MBI
638 select INTEL_IMR
9ab6eb51 639 select COMMON_CLK
a7f7f624 640 help
8bbc2a13
BD
641 Select to include support for Quark X1000 SoC.
642 Say Y here if you have a Quark based system such as the Arduino
643 compatible Intel Galileo.
644
3d48aab1
MW
645config X86_INTEL_LPSS
646 bool "Intel Low Power Subsystem Support"
5962dd22 647 depends on X86 && ACPI && PCI
3d48aab1 648 select COMMON_CLK
0f531431 649 select PINCTRL
eebb3e8d 650 select IOSF_MBI
a7f7f624 651 help
3d48aab1
MW
652 Select to build support for Intel Low Power Subsystem such as
653 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
654 things like clock tree (common clock framework) and pincontrol
655 which are needed by the LPSS peripheral drivers.
3d48aab1 656
92082a88
KX
657config X86_AMD_PLATFORM_DEVICE
658 bool "AMD ACPI2Platform devices support"
659 depends on ACPI
660 select COMMON_CLK
661 select PINCTRL
a7f7f624 662 help
92082a88
KX
663 Select to interpret AMD specific ACPI device to platform device
664 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
665 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
666 implemented under PINCTRL subsystem.
667
ced3ce76
DB
668config IOSF_MBI
669 tristate "Intel SoC IOSF Sideband support for SoC platforms"
670 depends on PCI
a7f7f624 671 help
ced3ce76
DB
672 This option enables sideband register access support for Intel SoC
673 platforms. On these platforms the IOSF sideband is used in lieu of
674 MSR's for some register accesses, mostly but not limited to thermal
675 and power. Drivers may query the availability of this device to
676 determine if they need the sideband in order to work on these
677 platforms. The sideband is available on the following SoC products.
678 This list is not meant to be exclusive.
679 - BayTrail
680 - Braswell
681 - Quark
682
683 You should say Y if you are running a kernel on one of these SoC's.
684
ed2226bd
DB
685config IOSF_MBI_DEBUG
686 bool "Enable IOSF sideband access through debugfs"
687 depends on IOSF_MBI && DEBUG_FS
a7f7f624 688 help
ed2226bd
DB
689 Select this option to expose the IOSF sideband access registers (MCR,
690 MDR, MCRX) through debugfs to write and read register information from
691 different units on the SoC. This is most useful for obtaining device
692 state information for debug and analysis. As this is a general access
693 mechanism, users of this option would have specific knowledge of the
694 device they want to access.
695
696 If you don't require the option or are in doubt, say N.
697
c5c606d9
RT
698config X86_RDC321X
699 bool "RDC R-321x SoC"
506f1d07 700 depends on X86_32
c5c606d9
RT
701 depends on X86_EXTENDED_PLATFORM
702 select M486
703 select X86_REBOOTFIXUPS
a7f7f624 704 help
c5c606d9
RT
705 This option is needed for RDC R-321x system-on-chip, also known
706 as R-8610-(G).
707 If you don't have one of these chips, you should say N here.
708
e0c7ae37 709config X86_32_NON_STANDARD
9c398017
IM
710 bool "Support non-standard 32-bit SMP architectures"
711 depends on X86_32 && SMP
c5c606d9 712 depends on X86_EXTENDED_PLATFORM
a7f7f624 713 help
b5660ba7
PA
714 This option compiles in the bigsmp and STA2X11 default
715 subarchitectures. It is intended for a generic binary
716 kernel. If you select them all, kernel will probe it one by
717 one and will fallback to default.
d49c4288 718
c5c606d9 719# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 720
d949f36f 721config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 722 def_bool y
d949f36f
LT
723 # MCE code calls memory_failure():
724 depends on X86_MCE
725 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
726 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
727 depends on X86_64 || !SPARSEMEM
728 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 729
83125a3a
AR
730config STA2X11
731 bool "STA2X11 Companion Chip Support"
732 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
733 select SWIOTLB
734 select MFD_STA2X11
0145071b 735 select GPIOLIB
a7f7f624 736 help
83125a3a
AR
737 This adds support for boards based on the STA2X11 IO-Hub,
738 a.k.a. "ConneXt". The chip is used in place of the standard
739 PC chipset, so all "standard" peripherals are missing. If this
740 option is selected the kernel will still be able to boot on
741 standard PC machines.
742
82148d1d
S
743config X86_32_IRIS
744 tristate "Eurobraille/Iris poweroff module"
745 depends on X86_32
a7f7f624 746 help
82148d1d
S
747 The Iris machines from EuroBraille do not have APM or ACPI support
748 to shut themselves down properly. A special I/O sequence is
749 needed to do so, which is what this module does at
750 kernel shutdown.
751
752 This is only for Iris machines from EuroBraille.
753
754 If unused, say N.
755
ae1e9130 756config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
757 def_bool y
758 prompt "Single-depth WCHAN output"
a87d0914 759 depends on X86
a7f7f624 760 help
506f1d07
SR
761 Calculate simpler /proc/<PID>/wchan values. If this option
762 is disabled then wchan values will recurse back to the
763 caller function. This provides more accurate wchan values,
764 at the expense of slightly more scheduling overhead.
765
766 If in doubt, say "Y".
767
6276a074
BP
768menuconfig HYPERVISOR_GUEST
769 bool "Linux guest support"
a7f7f624 770 help
6276a074
BP
771 Say Y here to enable options for running Linux under various hyper-
772 visors. This option enables basic hypervisor detection and platform
773 setup.
506f1d07 774
6276a074
BP
775 If you say N, all options in this submenu will be skipped and
776 disabled, and Linux guest support won't be built in.
506f1d07 777
6276a074 778if HYPERVISOR_GUEST
506f1d07 779
e61bd94a
EPH
780config PARAVIRT
781 bool "Enable paravirtualization code"
a0e2bf7c 782 depends on HAVE_STATIC_CALL
a7f7f624 783 help
e61bd94a
EPH
784 This changes the kernel so it can modify itself when it is run
785 under a hypervisor, potentially improving performance significantly
786 over full virtualization. However, when run without a hypervisor
787 the kernel is theoretically slower and slightly larger.
788
c00a280a
JG
789config PARAVIRT_XXL
790 bool
791
6276a074
BP
792config PARAVIRT_DEBUG
793 bool "paravirt-ops debugging"
794 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 795 help
6276a074
BP
796 Enable to debug paravirt_ops internals. Specifically, BUG if
797 a paravirt_op is missing when it is called.
798
b4ecc126
JF
799config PARAVIRT_SPINLOCKS
800 bool "Paravirtualization layer for spinlocks"
6ea30386 801 depends on PARAVIRT && SMP
a7f7f624 802 help
b4ecc126
JF
803 Paravirtualized spinlocks allow a pvops backend to replace the
804 spinlock implementation with something virtualization-friendly
805 (for example, block the virtual CPU rather than spinning).
806
4c4e4f61
R
807 It has a minimal impact on native kernels and gives a nice performance
808 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 809
4c4e4f61 810 If you are unsure how to answer this question, answer Y.
b4ecc126 811
ecca2502
ZY
812config X86_HV_CALLBACK_VECTOR
813 def_bool n
814
6276a074 815source "arch/x86/xen/Kconfig"
7af192c9 816
6276a074
BP
817config KVM_GUEST
818 bool "KVM Guest support (including kvmclock)"
819 depends on PARAVIRT
820 select PARAVIRT_CLOCK
a1c4423b 821 select ARCH_CPUIDLE_HALTPOLL
b1d40575 822 select X86_HV_CALLBACK_VECTOR
6276a074 823 default y
a7f7f624 824 help
6276a074
BP
825 This option enables various optimizations for running under the KVM
826 hypervisor. It includes a paravirtualized clock, so that instead
827 of relying on a PIT (or probably other) emulation by the
828 underlying device model, the host provides the guest with
829 timing infrastructure such as time of day, and system time
506f1d07 830
a1c4423b 831config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
832 def_bool n
833 prompt "Disable host haltpoll when loading haltpoll driver"
834 help
a1c4423b
MT
835 If virtualized under KVM, disable host haltpoll.
836
7733607f
MW
837config PVH
838 bool "Support for running PVH guests"
a7f7f624 839 help
7733607f
MW
840 This option enables the PVH entry point for guest virtual machines
841 as specified in the x86/HVM direct boot ABI.
842
6276a074
BP
843config PARAVIRT_TIME_ACCOUNTING
844 bool "Paravirtual steal time accounting"
845 depends on PARAVIRT
a7f7f624 846 help
6276a074
BP
847 Select this option to enable fine granularity task steal time
848 accounting. Time spent executing other tasks in parallel with
849 the current vCPU is discounted from the vCPU power. To account for
850 that, there can be a small performance impact.
851
852 If in doubt, say N here.
853
854config PARAVIRT_CLOCK
855 bool
97349135 856
4a362601
JK
857config JAILHOUSE_GUEST
858 bool "Jailhouse non-root cell support"
abde587b 859 depends on X86_64 && PCI
87e65d05 860 select X86_PM_TIMER
a7f7f624 861 help
4a362601
JK
862 This option allows to run Linux as guest in a Jailhouse non-root
863 cell. You can leave this option disabled if you only want to start
864 Jailhouse and run Linux afterwards in the root cell.
865
ec7972c9
ZY
866config ACRN_GUEST
867 bool "ACRN Guest support"
868 depends on X86_64
498ad393 869 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
870 help
871 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
872 a flexible, lightweight reference open-source hypervisor, built with
873 real-time and safety-criticality in mind. It is built for embedded
874 IOT with small footprint and real-time features. More details can be
875 found in https://projectacrn.org/.
876
59bd54a8
KS
877config INTEL_TDX_GUEST
878 bool "Intel TDX (Trust Domain Extensions) - Guest Support"
879 depends on X86_64 && CPU_SUP_INTEL
880 depends on X86_X2APIC
75d090fd 881 depends on EFI_STUB
41394e33 882 select ARCH_HAS_CC_PLATFORM
968b4931 883 select X86_MEM_ENCRYPT
77a512e3 884 select X86_MCE
75d090fd 885 select UNACCEPTED_MEMORY
59bd54a8
KS
886 help
887 Support running as a guest under Intel TDX. Without this support,
888 the guest kernel can not boot or run under TDX.
889 TDX includes memory encryption and integrity capabilities
890 which protect the confidentiality and integrity of guest
891 memory contents and CPU state. TDX guests are protected from
892 some attacks from the VMM.
893
758cd94a 894endif # HYPERVISOR_GUEST
97349135 895
506f1d07
SR
896source "arch/x86/Kconfig.cpu"
897
898config HPET_TIMER
3c2362e6 899 def_bool X86_64
506f1d07 900 prompt "HPET Timer Support" if X86_32
a7f7f624 901 help
8f9ca475
IM
902 Use the IA-PC HPET (High Precision Event Timer) to manage
903 time in preference to the PIT and RTC, if a HPET is
904 present.
905 HPET is the next generation timer replacing legacy 8254s.
906 The HPET provides a stable time base on SMP
907 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
908 as it is off-chip. The interface used is documented
909 in the HPET spec, revision 1.
506f1d07 910
8f9ca475
IM
911 You can safely choose Y here. However, HPET will only be
912 activated if the platform and the BIOS support this feature.
913 Otherwise the 8254 will be used for timing services.
506f1d07 914
8f9ca475 915 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
916
917config HPET_EMULATE_RTC
3c2362e6 918 def_bool y
3228e1dc 919 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 920
6a108a14 921# Mark as expert because too many people got it wrong.
506f1d07 922# The code disables itself when not needed.
7ae9392c
TP
923config DMI
924 default y
cf074402 925 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 926 bool "Enable DMI scanning" if EXPERT
a7f7f624 927 help
7ae9392c
TP
928 Enabled scanning of DMI to identify machine quirks. Say Y
929 here unless you have verified that your setup is not
930 affected by entries in the DMI blacklist. Required by PNP
931 BIOS code.
932
506f1d07 933config GART_IOMMU
38901f1c 934 bool "Old AMD GART IOMMU support"
2f9237d4 935 select DMA_OPS
a4ce5a48 936 select IOMMU_HELPER
506f1d07 937 select SWIOTLB
23ac4ae8 938 depends on X86_64 && PCI && AMD_NB
a7f7f624 939 help
ced3c42c
IM
940 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
941 GART based hardware IOMMUs.
942
943 The GART supports full DMA access for devices with 32-bit access
944 limitations, on systems with more than 3 GB. This is usually needed
945 for USB, sound, many IDE/SATA chipsets and some other devices.
946
947 Newer systems typically have a modern AMD IOMMU, supported via
948 the CONFIG_AMD_IOMMU=y config option.
949
950 In normal configurations this driver is only active when needed:
951 there's more than 3 GB of memory and the system contains a
952 32-bit limited device.
953
954 If unsure, say Y.
506f1d07 955
8b766b0f
MS
956config BOOT_VESA_SUPPORT
957 bool
958 help
959 If true, at least one selected framebuffer driver can take advantage
960 of VESA video modes set at an early boot stage via the vga= parameter.
506f1d07 961
1184dc2f 962config MAXSMP
ddb0c5a6 963 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 964 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 965 select CPUMASK_OFFSTACK
a7f7f624 966 help
ddb0c5a6 967 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 968 If unsure, say N.
506f1d07 969
aec6487e
IM
970#
971# The maximum number of CPUs supported:
972#
973# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
974# and which can be configured interactively in the
975# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
976#
977# The ranges are different on 32-bit and 64-bit kernels, depending on
978# hardware capabilities and scalability features of the kernel.
979#
980# ( If MAXSMP is enabled we just use the highest possible value and disable
981# interactive configuration. )
982#
983
984config NR_CPUS_RANGE_BEGIN
a0d0bb4d 985 int
aec6487e
IM
986 default NR_CPUS_RANGE_END if MAXSMP
987 default 1 if !SMP
988 default 2
a0d0bb4d 989
aec6487e 990config NR_CPUS_RANGE_END
a0d0bb4d 991 int
aec6487e
IM
992 depends on X86_32
993 default 64 if SMP && X86_BIGSMP
994 default 8 if SMP && !X86_BIGSMP
995 default 1 if !SMP
a0d0bb4d 996
aec6487e 997config NR_CPUS_RANGE_END
a0d0bb4d 998 int
aec6487e 999 depends on X86_64
1edae1ae
SW
1000 default 8192 if SMP && CPUMASK_OFFSTACK
1001 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 1002 default 1 if !SMP
a0d0bb4d 1003
aec6487e 1004config NR_CPUS_DEFAULT
a0d0bb4d
RD
1005 int
1006 depends on X86_32
aec6487e
IM
1007 default 32 if X86_BIGSMP
1008 default 8 if SMP
1009 default 1 if !SMP
a0d0bb4d 1010
aec6487e 1011config NR_CPUS_DEFAULT
a0d0bb4d
RD
1012 int
1013 depends on X86_64
aec6487e
IM
1014 default 8192 if MAXSMP
1015 default 64 if SMP
1016 default 1 if !SMP
a0d0bb4d 1017
506f1d07 1018config NR_CPUS
36f5101a 1019 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
1020 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1021 default NR_CPUS_DEFAULT
a7f7f624 1022 help
506f1d07 1023 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1024 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1025 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1026 minimum value which makes sense is 2.
1027
aec6487e
IM
1028 This is purely to save memory: each supported CPU adds about 8KB
1029 to the kernel image.
506f1d07 1030
66558b73
TC
1031config SCHED_CLUSTER
1032 bool "Cluster scheduler support"
1033 depends on SMP
1034 default y
1035 help
1036 Cluster scheduler support improves the CPU scheduler's decision
1037 making when dealing with machines that have clusters of CPUs.
1038 Cluster usually means a couple of CPUs which are placed closely
1039 by sharing mid-level caches, last-level cache tags or internal
1040 busses.
1041
506f1d07 1042config SCHED_SMT
dbe73364 1043 def_bool y if SMP
506f1d07
SR
1044
1045config SCHED_MC
3c2362e6
HH
1046 def_bool y
1047 prompt "Multi-core scheduler support"
c8e56d20 1048 depends on SMP
a7f7f624 1049 help
506f1d07
SR
1050 Multi-core scheduler support improves the CPU scheduler's decision
1051 making when dealing with multi-core CPU chips at a cost of slightly
1052 increased overhead in some places. If unsure say N here.
1053
de966cf4
TC
1054config SCHED_MC_PRIO
1055 bool "CPU core priorities scheduler support"
0a21fc12
IM
1056 depends on SCHED_MC && CPU_SUP_INTEL
1057 select X86_INTEL_PSTATE
1058 select CPU_FREQ
de966cf4 1059 default y
a7f7f624 1060 help
0a21fc12
IM
1061 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1062 core ordering determined at manufacturing time, which allows
1063 certain cores to reach higher turbo frequencies (when running
1064 single threaded workloads) than others.
de966cf4 1065
0a21fc12
IM
1066 Enabling this kernel feature teaches the scheduler about
1067 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1068 scheduler's CPU selection logic accordingly, so that higher
1069 overall system performance can be achieved.
de966cf4 1070
0a21fc12 1071 This feature will have no effect on CPUs without this feature.
de966cf4 1072
0a21fc12 1073 If unsure say Y here.
5e76b2ab 1074
30b8b006 1075config UP_LATE_INIT
b03b016f
KK
1076 def_bool y
1077 depends on !SMP && X86_LOCAL_APIC
30b8b006 1078
506f1d07 1079config X86_UP_APIC
50849eef
JB
1080 bool "Local APIC support on uniprocessors" if !PCI_MSI
1081 default PCI_MSI
38a1dfda 1082 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1083 help
506f1d07
SR
1084 A local APIC (Advanced Programmable Interrupt Controller) is an
1085 integrated interrupt controller in the CPU. If you have a single-CPU
1086 system which has a processor with a local APIC, you can say Y here to
1087 enable and use it. If you say Y here even though your machine doesn't
1088 have a local APIC, then the kernel will still run with no slowdown at
1089 all. The local APIC supports CPU-generated self-interrupts (timer,
1090 performance counters), and the NMI watchdog which detects hard
1091 lockups.
1092
1093config X86_UP_IOAPIC
1094 bool "IO-APIC support on uniprocessors"
1095 depends on X86_UP_APIC
a7f7f624 1096 help
506f1d07
SR
1097 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1098 SMP-capable replacement for PC-style interrupt controllers. Most
1099 SMP systems and many recent uniprocessor systems have one.
1100
1101 If you have a single-CPU system with an IO-APIC, you can say Y here
1102 to use it. If you say Y here even though your machine doesn't have
1103 an IO-APIC, then the kernel will still run with no slowdown at all.
1104
1105config X86_LOCAL_APIC
3c2362e6 1106 def_bool y
0dbc6078 1107 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1108 select IRQ_DOMAIN_HIERARCHY
506f1d07
SR
1109
1110config X86_IO_APIC
b1da1e71
JB
1111 def_bool y
1112 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1113
41b9eb26
SA
1114config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1115 bool "Reroute for broken boot IRQs"
41b9eb26 1116 depends on X86_IO_APIC
a7f7f624 1117 help
41b9eb26
SA
1118 This option enables a workaround that fixes a source of
1119 spurious interrupts. This is recommended when threaded
1120 interrupt handling is used on systems where the generation of
1121 superfluous "boot interrupts" cannot be disabled.
1122
1123 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1124 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1125 kernel does during interrupt handling). On chipsets where this
1126 boot IRQ generation cannot be disabled, this workaround keeps
1127 the original IRQ line masked so that only the equivalent "boot
1128 IRQ" is delivered to the CPUs. The workaround also tells the
1129 kernel to set up the IRQ handler on the boot IRQ line. In this
1130 way only one interrupt is delivered to the kernel. Otherwise
1131 the spurious second interrupt may cause the kernel to bring
1132 down (vital) interrupt lines.
1133
1134 Only affects "broken" chipsets. Interrupt sharing may be
1135 increased on these systems.
1136
506f1d07 1137config X86_MCE
bab9bc65 1138 bool "Machine Check / overheating reporting"
648ed940 1139 select GENERIC_ALLOCATOR
e57dbaf7 1140 default y
a7f7f624 1141 help
bab9bc65
AK
1142 Machine Check support allows the processor to notify the
1143 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1144 The action the kernel takes depends on the severity of the problem,
bab9bc65 1145 ranging from warning messages to halting the machine.
4efc0670 1146
5de97c9f
TL
1147config X86_MCELOG_LEGACY
1148 bool "Support for deprecated /dev/mcelog character device"
1149 depends on X86_MCE
a7f7f624 1150 help
5de97c9f
TL
1151 Enable support for /dev/mcelog which is needed by the old mcelog
1152 userspace logging daemon. Consider switching to the new generation
1153 rasdaemon solution.
1154
506f1d07 1155config X86_MCE_INTEL
3c2362e6
HH
1156 def_bool y
1157 prompt "Intel MCE features"
c1ebf835 1158 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1159 help
758cd94a
JH
1160 Additional support for intel specific MCE features such as
1161 the thermal monitor.
506f1d07
SR
1162
1163config X86_MCE_AMD
3c2362e6
HH
1164 def_bool y
1165 prompt "AMD MCE features"
f5382de9 1166 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
a7f7f624 1167 help
758cd94a
JH
1168 Additional support for AMD specific MCE features such as
1169 the DRAM Error Threshold.
506f1d07 1170
4efc0670 1171config X86_ANCIENT_MCE
6fc108a0 1172 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1173 depends on X86_32 && X86_MCE
a7f7f624 1174 help
cd13adcc 1175 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1176 systems. These typically need to be enabled explicitly on the command
cd13adcc 1177 line.
4efc0670 1178
b2762686
AK
1179config X86_MCE_THRESHOLD
1180 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1181 def_bool y
b2762686 1182
ea149b36 1183config X86_MCE_INJECT
bc8e80d5 1184 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1185 tristate "Machine check injector support"
a7f7f624 1186 help
ea149b36
AK
1187 Provide support for injecting machine checks for testing purposes.
1188 If you don't know what a machine check is and you don't do kernel
1189 QA it is safe to say n.
1190
07dc900e 1191source "arch/x86/events/Kconfig"
e633c65a 1192
5aef51c3 1193config X86_LEGACY_VM86
1e642812 1194 bool "Legacy VM86 support"
506f1d07 1195 depends on X86_32
a7f7f624 1196 help
5aef51c3
AL
1197 This option allows user programs to put the CPU into V8086
1198 mode, which is an 80286-era approximation of 16-bit real mode.
1199
1200 Some very old versions of X and/or vbetool require this option
1201 for user mode setting. Similarly, DOSEMU will use it if
1202 available to accelerate real mode DOS programs. However, any
1203 recent version of DOSEMU, X, or vbetool should be fully
1204 functional even without kernel VM86 support, as they will all
1e642812
IM
1205 fall back to software emulation. Nevertheless, if you are using
1206 a 16-bit DOS program where 16-bit performance matters, vm86
1207 mode might be faster than emulation and you might want to
1208 enable this option.
5aef51c3 1209
1e642812
IM
1210 Note that any app that works on a 64-bit kernel is unlikely to
1211 need this option, as 64-bit kernels don't, and can't, support
1212 V8086 mode. This option is also unrelated to 16-bit protected
1213 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1214
1e642812
IM
1215 Enabling this option increases the complexity of the kernel
1216 and slows down exception handling a tiny bit.
5aef51c3 1217
1e642812 1218 If unsure, say N here.
5aef51c3
AL
1219
1220config VM86
b03b016f
KK
1221 bool
1222 default X86_LEGACY_VM86
34273f41
PA
1223
1224config X86_16BIT
1225 bool "Enable support for 16-bit segments" if EXPERT
1226 default y
a5b9e5a2 1227 depends on MODIFY_LDT_SYSCALL
a7f7f624 1228 help
34273f41
PA
1229 This option is required by programs like Wine to run 16-bit
1230 protected mode legacy code on x86 processors. Disabling
1231 this option saves about 300 bytes on i386, or around 6K text
1232 plus 16K runtime memory on x86-64,
1233
1234config X86_ESPFIX32
1235 def_bool y
1236 depends on X86_16BIT && X86_32
506f1d07 1237
197725de
PA
1238config X86_ESPFIX64
1239 def_bool y
34273f41 1240 depends on X86_16BIT && X86_64
506f1d07 1241
1ad83c85 1242config X86_VSYSCALL_EMULATION
b03b016f
KK
1243 bool "Enable vsyscall emulation" if EXPERT
1244 default y
1245 depends on X86_64
a7f7f624 1246 help
758cd94a
JH
1247 This enables emulation of the legacy vsyscall page. Disabling
1248 it is roughly equivalent to booting with vsyscall=none, except
1249 that it will also disable the helpful warning if a program
1250 tries to use a vsyscall. With this option set to N, offending
1251 programs will just segfault, citing addresses of the form
1252 0xffffffffff600?00.
1ad83c85 1253
758cd94a
JH
1254 This option is required by many programs built before 2013, and
1255 care should be used even with newer programs if set to N.
1ad83c85 1256
758cd94a
JH
1257 Disabling this option saves about 7K of kernel size and
1258 possibly 4K of additional runtime pagetable memory.
1ad83c85 1259
111e7b15
TG
1260config X86_IOPL_IOPERM
1261 bool "IOPERM and IOPL Emulation"
a24ca997 1262 default y
a7f7f624 1263 help
111e7b15
TG
1264 This enables the ioperm() and iopl() syscalls which are necessary
1265 for legacy applications.
1266
c8137ace
TG
1267 Legacy IOPL support is an overbroad mechanism which allows user
1268 space aside of accessing all 65536 I/O ports also to disable
1269 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1270 capabilities and permission from potentially active security
1271 modules.
1272
1273 The emulation restricts the functionality of the syscall to
1274 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1275 ability to disable interrupts from user space which would be
1276 granted if the hardware IOPL mechanism would be used.
c8137ace 1277
506f1d07
SR
1278config TOSHIBA
1279 tristate "Toshiba Laptop support"
1280 depends on X86_32
a7f7f624 1281 help
506f1d07
SR
1282 This adds a driver to safely access the System Management Mode of
1283 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1284 not work on models with a Phoenix BIOS. The System Management Mode
1285 is used to set the BIOS and power saving options on Toshiba portables.
1286
1287 For information on utilities to make use of this driver see the
1288 Toshiba Linux utilities web site at:
1289 <http://www.buzzard.org.uk/toshiba/>.
1290
1291 Say Y if you intend to run this kernel on a Toshiba portable.
1292 Say N otherwise.
1293
506f1d07 1294config X86_REBOOTFIXUPS
9ba16087
JB
1295 bool "Enable X86 board specific fixups for reboot"
1296 depends on X86_32
a7f7f624 1297 help
506f1d07
SR
1298 This enables chipset and/or board specific fixups to be done
1299 in order to get reboot to work correctly. This is only needed on
1300 some combinations of hardware and BIOS. The symptom, for which
1301 this config is intended, is when reboot ends with a stalled/hung
1302 system.
1303
1304 Currently, the only fixup is for the Geode machines using
5e3a77e9 1305 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1306
1307 Say Y if you want to enable the fixup. Currently, it's safe to
1308 enable this option even if you don't need it.
1309 Say N otherwise.
1310
1311config MICROCODE
e6bcfdd7 1312 def_bool y
80030e3d 1313 depends on CPU_SUP_AMD || CPU_SUP_INTEL
80cc9f10 1314
fdbd4381
TG
1315config MICROCODE_INITRD32
1316 def_bool y
1317 depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1318
a77a94f8
BP
1319config MICROCODE_LATE_LOADING
1320 bool "Late microcode loading (DANGEROUS)"
c02f48e0 1321 default n
634ac23a 1322 depends on MICROCODE && SMP
a7f7f624 1323 help
a77a94f8
BP
1324 Loading microcode late, when the system is up and executing instructions
1325 is a tricky business and should be avoided if possible. Just the sequence
1326 of synchronizing all cores and SMT threads is one fragile dance which does
1327 not guarantee that cores might not softlock after the loading. Therefore,
9407bda8
TG
1328 use this at your own risk. Late loading taints the kernel unless the
1329 microcode header indicates that it is safe for late loading via the
1330 minimal revision check. This minimal revision check can be enforced on
1331 the kernel command line with "microcode.minrev=Y".
1332
1333config MICROCODE_LATE_FORCE_MINREV
1334 bool "Enforce late microcode loading minimal revision check"
1335 default n
1336 depends on MICROCODE_LATE_LOADING
1337 help
1338 To prevent that users load microcode late which modifies already
1339 in use features, newer microcode patches have a minimum revision field
1340 in the microcode header, which tells the kernel which minimum
1341 revision must be active in the CPU to safely load that new microcode
1342 late into the running system. If disabled the check will not
1343 be enforced but the kernel will be tainted when the minimal
1344 revision check fails.
1345
1346 This minimal revision check can also be controlled via the
1347 "microcode.minrev" parameter on the kernel command line.
1348
1349 If unsure say Y.
506f1d07
SR
1350
1351config X86_MSR
1352 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1353 help
506f1d07
SR
1354 This device gives privileged processes access to the x86
1355 Model-Specific Registers (MSRs). It is a character device with
1356 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1357 MSR accesses are directed to a specific CPU on multi-processor
1358 systems.
1359
1360config X86_CPUID
1361 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1362 help
506f1d07
SR
1363 This device gives processes access to the x86 CPUID instruction to
1364 be executed on a specific processor. It is a character device
1365 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1366 /dev/cpu/31/cpuid.
1367
1368choice
1369 prompt "High Memory Support"
6fc108a0 1370 default HIGHMEM4G
506f1d07
SR
1371 depends on X86_32
1372
1373config NOHIGHMEM
1374 bool "off"
a7f7f624 1375 help
506f1d07
SR
1376 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1377 However, the address space of 32-bit x86 processors is only 4
1378 Gigabytes large. That means that, if you have a large amount of
1379 physical memory, not all of it can be "permanently mapped" by the
1380 kernel. The physical memory that's not permanently mapped is called
1381 "high memory".
1382
1383 If you are compiling a kernel which will never run on a machine with
1384 more than 1 Gigabyte total physical RAM, answer "off" here (default
1385 choice and suitable for most users). This will result in a "3GB/1GB"
1386 split: 3GB are mapped so that each process sees a 3GB virtual memory
1387 space and the remaining part of the 4GB virtual memory space is used
1388 by the kernel to permanently map as much physical memory as
1389 possible.
1390
1391 If the machine has between 1 and 4 Gigabytes physical RAM, then
1392 answer "4GB" here.
1393
1394 If more than 4 Gigabytes is used then answer "64GB" here. This
1395 selection turns Intel PAE (Physical Address Extension) mode on.
1396 PAE implements 3-level paging on IA32 processors. PAE is fully
1397 supported by Linux, PAE mode is implemented on all recent Intel
1398 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1399 then the kernel will not boot on CPUs that don't support PAE!
1400
1401 The actual amount of total physical memory will either be
1402 auto detected or can be forced by using a kernel command line option
1403 such as "mem=256M". (Try "man bootparam" or see the documentation of
1404 your boot loader (lilo or loadlin) about how to pass options to the
1405 kernel at boot time.)
1406
1407 If unsure, say "off".
1408
1409config HIGHMEM4G
1410 bool "4GB"
a7f7f624 1411 help
506f1d07
SR
1412 Select this if you have a 32-bit processor and between 1 and 4
1413 gigabytes of physical RAM.
1414
1415config HIGHMEM64G
1416 bool "64GB"
88a2b4ed 1417 depends on X86_HAVE_PAE
506f1d07 1418 select X86_PAE
a7f7f624 1419 help
506f1d07
SR
1420 Select this if you have a 32-bit processor and more than 4
1421 gigabytes of physical RAM.
1422
1423endchoice
1424
1425choice
6a108a14 1426 prompt "Memory split" if EXPERT
506f1d07
SR
1427 default VMSPLIT_3G
1428 depends on X86_32
a7f7f624 1429 help
506f1d07
SR
1430 Select the desired split between kernel and user memory.
1431
1432 If the address range available to the kernel is less than the
1433 physical memory installed, the remaining memory will be available
1434 as "high memory". Accessing high memory is a little more costly
1435 than low memory, as it needs to be mapped into the kernel first.
1436 Note that increasing the kernel address space limits the range
1437 available to user programs, making the address space there
1438 tighter. Selecting anything other than the default 3G/1G split
1439 will also likely make your kernel incompatible with binary-only
1440 kernel modules.
1441
1442 If you are not absolutely sure what you are doing, leave this
1443 option alone!
1444
1445 config VMSPLIT_3G
1446 bool "3G/1G user/kernel split"
1447 config VMSPLIT_3G_OPT
1448 depends on !X86_PAE
1449 bool "3G/1G user/kernel split (for full 1G low memory)"
1450 config VMSPLIT_2G
1451 bool "2G/2G user/kernel split"
1452 config VMSPLIT_2G_OPT
1453 depends on !X86_PAE
1454 bool "2G/2G user/kernel split (for full 2G low memory)"
1455 config VMSPLIT_1G
1456 bool "1G/3G user/kernel split"
1457endchoice
1458
1459config PAGE_OFFSET
1460 hex
1461 default 0xB0000000 if VMSPLIT_3G_OPT
1462 default 0x80000000 if VMSPLIT_2G
1463 default 0x78000000 if VMSPLIT_2G_OPT
1464 default 0x40000000 if VMSPLIT_1G
1465 default 0xC0000000
1466 depends on X86_32
1467
1468config HIGHMEM
3c2362e6 1469 def_bool y
506f1d07 1470 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1471
1472config X86_PAE
9ba16087 1473 bool "PAE (Physical Address Extension) Support"
88a2b4ed 1474 depends on X86_32 && X86_HAVE_PAE
d4a451d5 1475 select PHYS_ADDR_T_64BIT
9d99c712 1476 select SWIOTLB
a7f7f624 1477 help
506f1d07
SR
1478 PAE is required for NX support, and furthermore enables
1479 larger swapspace support for non-overcommit purposes. It
1480 has the cost of more pagetable lookup overhead, and also
1481 consumes more pagetable space per process.
1482
77ef56e4
KS
1483config X86_5LEVEL
1484 bool "Enable 5-level page tables support"
18ec1eaf 1485 default y
eedb92ab 1486 select DYNAMIC_MEMORY_LAYOUT
162434e7 1487 select SPARSEMEM_VMEMMAP
77ef56e4 1488 depends on X86_64
a7f7f624 1489 help
77ef56e4 1490 5-level paging enables access to larger address space:
54628de6 1491 up to 128 PiB of virtual address space and 4 PiB of
77ef56e4
KS
1492 physical address space.
1493
1494 It will be supported by future Intel CPUs.
1495
6657fca0
KS
1496 A kernel with the option enabled can be booted on machines that
1497 support 4- or 5-level paging.
77ef56e4 1498
ff61f079 1499 See Documentation/arch/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1500 information.
1501
1502 Say N if unsure.
1503
10971ab2 1504config X86_DIRECT_GBPAGES
e5008abe 1505 def_bool y
2e1da13f 1506 depends on X86_64
a7f7f624 1507 help
10971ab2
IM
1508 Certain kernel features effectively disable kernel
1509 linear 1 GB mappings (even if the CPU otherwise
1510 supports them), so don't confuse the user by printing
1511 that we have them enabled.
9e899816 1512
5c280cf6
TG
1513config X86_CPA_STATISTICS
1514 bool "Enable statistic for Change Page Attribute"
1515 depends on DEBUG_FS
a7f7f624 1516 help
b75baaf3 1517 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1518 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1519 page mappings when mapping protections are changed.
1520
20f07a04
KS
1521config X86_MEM_ENCRYPT
1522 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1523 select DYNAMIC_PHYSICAL_MASK
20f07a04
KS
1524 def_bool n
1525
7744ccdb
TL
1526config AMD_MEM_ENCRYPT
1527 bool "AMD Secure Memory Encryption (SME) support"
1528 depends on X86_64 && CPU_SUP_AMD
6c321179 1529 depends on EFI_STUB
82fef0ad 1530 select DMA_COHERENT_POOL
ce9084ba 1531 select ARCH_USE_MEMREMAP_PROT
597cfe48 1532 select INSTRUCTION_DECODER
aa5a4611 1533 select ARCH_HAS_CC_PLATFORM
20f07a04 1534 select X86_MEM_ENCRYPT
6c321179 1535 select UNACCEPTED_MEMORY
a7f7f624 1536 help
7744ccdb
TL
1537 Say yes to enable support for the encryption of system memory.
1538 This requires an AMD processor that supports Secure Memory
1539 Encryption (SME).
1540
1541config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1542 bool "Activate AMD Secure Memory Encryption (SME) by default"
7744ccdb 1543 depends on AMD_MEM_ENCRYPT
a7f7f624 1544 help
7744ccdb
TL
1545 Say yes to have system memory encrypted by default if running on
1546 an AMD processor that supports Secure Memory Encryption (SME).
1547
1548 If set to Y, then the encryption of system memory can be
1549 deactivated with the mem_encrypt=off command line option.
1550
1551 If set to N, then the encryption of system memory can be
1552 activated with the mem_encrypt=on command line option.
1553
506f1d07
SR
1554# Common NUMA Features
1555config NUMA
e133f6ea 1556 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1557 depends on SMP
b5660ba7
PA
1558 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1559 default y if X86_BIGSMP
7ecd19cf 1560 select USE_PERCPU_NUMA_NODE_ID
0c436a58 1561 select OF_NUMA if OF
a7f7f624 1562 help
e133f6ea 1563 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1564
506f1d07
SR
1565 The kernel will try to allocate memory used by a CPU on the
1566 local memory controller of the CPU and add some more
1567 NUMA awareness to the kernel.
1568
c280ea5e 1569 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1570 (or later), AMD Opteron, or EM64T NUMA.
1571
b5660ba7 1572 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1573 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1574
1575 Otherwise, you should say N.
506f1d07 1576
eec1d4fa 1577config AMD_NUMA
3c2362e6
HH
1578 def_bool y
1579 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1580 depends on X86_64 && NUMA && PCI
a7f7f624 1581 help
eec1d4fa
HR
1582 Enable AMD NUMA node topology detection. You should say Y here if
1583 you have a multi processor AMD system. This uses an old method to
1584 read the NUMA configuration directly from the builtin Northbridge
1585 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1586 which also takes priority if both are compiled in.
506f1d07
SR
1587
1588config X86_64_ACPI_NUMA
3c2362e6
HH
1589 def_bool y
1590 prompt "ACPI NUMA detection"
506f1d07
SR
1591 depends on X86_64 && NUMA && ACPI && PCI
1592 select ACPI_NUMA
a7f7f624 1593 help
506f1d07
SR
1594 Enable ACPI SRAT based node topology detection.
1595
1596config NUMA_EMU
1597 bool "NUMA emulation"
1b7e03ef 1598 depends on NUMA
a7f7f624 1599 help
506f1d07
SR
1600 Enable NUMA emulation. A flat machine will be split
1601 into virtual nodes when booted with "numa=fake=N", where N is the
1602 number of nodes. This is only useful for debugging.
1603
1604config NODES_SHIFT
d25e26b6 1605 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1606 range 1 10
1607 default "10" if MAXSMP
506f1d07 1608 default "6" if X86_64
506f1d07 1609 default "3"
a9ee6cf5 1610 depends on NUMA
a7f7f624 1611 help
1184dc2f 1612 Specify the maximum number of NUMA Nodes available on the target
692105b8 1613 system. Increases memory reserved to accommodate various tables.
506f1d07 1614
506f1d07
SR
1615config ARCH_FLATMEM_ENABLE
1616 def_bool y
3b16651f 1617 depends on X86_32 && !NUMA
506f1d07 1618
506f1d07
SR
1619config ARCH_SPARSEMEM_ENABLE
1620 def_bool y
6ea30386 1621 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1622 select SPARSEMEM_STATIC if X86_32
1623 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1624
3b16651f 1625config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1626 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1627
506f1d07
SR
1628config ARCH_SELECT_MEMORY_MODEL
1629 def_bool y
4eda2bc3 1630 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
506f1d07
SR
1631
1632config ARCH_MEMORY_PROBE
a0842b70 1633 bool "Enable sysfs memory/probe interface"
5c11f00b 1634 depends on MEMORY_HOTPLUG
a0842b70
TK
1635 help
1636 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1637 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1638 If you are unsure how to answer this question, answer N.
506f1d07 1639
3b16651f
TH
1640config ARCH_PROC_KCORE_TEXT
1641 def_bool y
1642 depends on X86_64 && PROC_KCORE
1643
a29815a3 1644config ILLEGAL_POINTER_VALUE
b03b016f
KK
1645 hex
1646 default 0 if X86_32
1647 default 0xdead000000000000 if X86_64
a29815a3 1648
7a67832c
DW
1649config X86_PMEM_LEGACY_DEVICE
1650 bool
1651
ec776ef6 1652config X86_PMEM_LEGACY
7a67832c 1653 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1654 depends on PHYS_ADDR_T_64BIT
1655 depends on BLK_DEV
7a67832c 1656 select X86_PMEM_LEGACY_DEVICE
7b27a862 1657 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1658 select LIBNVDIMM
ec776ef6
CH
1659 help
1660 Treat memory marked using the non-standard e820 type of 12 as used
1661 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1662 The kernel will offer these regions to the 'pmem' driver so
1663 they can be used for persistent storage.
1664
1665 Say Y if unsure.
1666
506f1d07
SR
1667config HIGHPTE
1668 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1669 depends on HIGHMEM
a7f7f624 1670 help
506f1d07
SR
1671 The VM uses one page table entry for each page of physical memory.
1672 For systems with a lot of RAM, this can be wasteful of precious
1673 low memory. Setting this option will put user-space page table
1674 entries in high memory.
1675
9f077871 1676config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1677 bool "Check for low memory corruption"
a7f7f624 1678 help
8f9ca475
IM
1679 Periodically check for memory corruption in low memory, which
1680 is suspected to be caused by BIOS. Even when enabled in the
1681 configuration, it is disabled at runtime. Enable it by
1682 setting "memory_corruption_check=1" on the kernel command
1683 line. By default it scans the low 64k of memory every 60
1684 seconds; see the memory_corruption_check_size and
1685 memory_corruption_check_period parameters in
8c27ceff 1686 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1687
1688 When enabled with the default parameters, this option has
1689 almost no overhead, as it reserves a relatively small amount
1690 of memory and scans it infrequently. It both detects corruption
1691 and prevents it from affecting the running system.
1692
1693 It is, however, intended as a diagnostic tool; if repeatable
1694 BIOS-originated corruption always affects the same memory,
1695 you can use memmap= to prevent the kernel from using that
1696 memory.
9f077871 1697
c885df50 1698config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1699 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1700 depends on X86_CHECK_BIOS_CORRUPTION
1701 default y
a7f7f624 1702 help
8f9ca475
IM
1703 Set whether the default state of memory_corruption_check is
1704 on or off.
c885df50 1705
506f1d07
SR
1706config MATH_EMULATION
1707 bool
a5b9e5a2 1708 depends on MODIFY_LDT_SYSCALL
87d6021b 1709 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1710 help
506f1d07
SR
1711 Linux can emulate a math coprocessor (used for floating point
1712 operations) if you don't have one. 486DX and Pentium processors have
1713 a math coprocessor built in, 486SX and 386 do not, unless you added
1714 a 487DX or 387, respectively. (The messages during boot time can
1715 give you some hints here ["man dmesg"].) Everyone needs either a
1716 coprocessor or this emulation.
1717
1718 If you don't have a math coprocessor, you need to say Y here; if you
1719 say Y here even though you have a coprocessor, the coprocessor will
1720 be used nevertheless. (This behavior can be changed with the kernel
1721 command line option "no387", which comes handy if your coprocessor
1722 is broken. Try "man bootparam" or see the documentation of your boot
1723 loader (lilo or loadlin) about how to pass options to the kernel at
1724 boot time.) This means that it is a good idea to say Y here if you
1725 intend to use this kernel on different machines.
1726
1727 More information about the internals of the Linux math coprocessor
1728 emulation can be found in <file:arch/x86/math-emu/README>.
1729
1730 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1731 kernel, it won't hurt.
1732
1733config MTRR
6fc108a0 1734 def_bool y
6a108a14 1735 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1736 help
506f1d07
SR
1737 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1738 the Memory Type Range Registers (MTRRs) may be used to control
1739 processor access to memory ranges. This is most useful if you have
1740 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1741 allows bus write transfers to be combined into a larger transfer
1742 before bursting over the PCI/AGP bus. This can increase performance
1743 of image write operations 2.5 times or more. Saying Y here creates a
1744 /proc/mtrr file which may be used to manipulate your processor's
1745 MTRRs. Typically the X server should use this.
1746
1747 This code has a reasonably generic interface so that similar
1748 control registers on other processors can be easily supported
1749 as well:
1750
1751 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1752 Registers (ARRs) which provide a similar functionality to MTRRs. For
1753 these, the ARRs are used to emulate the MTRRs.
1754 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1755 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1756 write-combining. All of these processors are supported by this code
1757 and it makes sense to say Y here if you have one of them.
1758
1759 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1760 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1761 can lead to all sorts of problems, so it's good to say Y here.
1762
1763 You can safely say Y even if your machine doesn't have MTRRs, you'll
1764 just add about 9 KB to your kernel.
1765
ff61f079 1766 See <file:Documentation/arch/x86/mtrr.rst> for more information.
506f1d07 1767
95ffa243 1768config MTRR_SANITIZER
2ffb3501 1769 def_bool y
95ffa243
YL
1770 prompt "MTRR cleanup support"
1771 depends on MTRR
a7f7f624 1772 help
aba3728c
TG
1773 Convert MTRR layout from continuous to discrete, so X drivers can
1774 add writeback entries.
95ffa243 1775
aba3728c 1776 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1777 The largest mtrr entry size for a continuous block can be set with
aba3728c 1778 mtrr_chunk_size.
95ffa243 1779
2ffb3501 1780 If unsure, say Y.
95ffa243
YL
1781
1782config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1783 int "MTRR cleanup enable value (0-1)"
1784 range 0 1
1785 default "0"
95ffa243 1786 depends on MTRR_SANITIZER
a7f7f624 1787 help
f5098d62 1788 Enable mtrr cleanup default value
95ffa243 1789
12031a62
YL
1790config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1791 int "MTRR cleanup spare reg num (0-7)"
1792 range 0 7
1793 default "1"
1794 depends on MTRR_SANITIZER
a7f7f624 1795 help
12031a62 1796 mtrr cleanup spare entries default, it can be changed via
aba3728c 1797 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1798
2e5d9c85 1799config X86_PAT
6fc108a0 1800 def_bool y
6a108a14 1801 prompt "x86 PAT support" if EXPERT
2a8a2719 1802 depends on MTRR
a7f7f624 1803 help
2e5d9c85 1804 Use PAT attributes to setup page level cache control.
042b78e4 1805
2e5d9c85 1806 PATs are the modern equivalents of MTRRs and are much more
1807 flexible than MTRRs.
1808
1809 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1810 spontaneous reboots) or a non-working video driver.
2e5d9c85 1811
1812 If unsure, say Y.
1813
46cf98cd
VP
1814config ARCH_USES_PG_UNCACHED
1815 def_bool y
1816 depends on X86_PAT
1817
b971880f 1818config X86_UMIP
796ebc81 1819 def_bool y
b971880f 1820 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1821 help
b971880f
BM
1822 User Mode Instruction Prevention (UMIP) is a security feature in
1823 some x86 processors. If enabled, a general protection fault is
1824 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1825 executed in user mode. These instructions unnecessarily expose
1826 information about the hardware state.
796ebc81
RN
1827
1828 The vast majority of applications do not use these instructions.
1829 For the very few that do, software emulation is provided in
1830 specific cases in protected and virtual-8086 modes. Emulated
1831 results are dummy.
aa35f896 1832
156ff4a5
PZ
1833config CC_HAS_IBT
1834 # GCC >= 9 and binutils >= 2.29
1835 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1836 # Clang/LLVM >= 14
262448f3
NC
1837 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1838 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
156ff4a5 1839 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
262448f3 1840 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
156ff4a5
PZ
1841 $(as-instr,endbr64)
1842
18e66b69
RE
1843config X86_CET
1844 def_bool n
1845 help
1846 CET features configured (Shadow stack or IBT)
1847
156ff4a5
PZ
1848config X86_KERNEL_IBT
1849 prompt "Indirect Branch Tracking"
4fd5f70c 1850 def_bool y
03f16cd0 1851 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
f6a2c2b2
NC
1852 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1853 depends on !LD_IS_LLD || LLD_VERSION >= 140000
03f16cd0 1854 select OBJTOOL
18e66b69 1855 select X86_CET
156ff4a5
PZ
1856 help
1857 Build the kernel with support for Indirect Branch Tracking, a
1858 hardware support course-grain forward-edge Control Flow Integrity
1859 protection. It enforces that all indirect calls must land on
1860 an ENDBR instruction, as such, the compiler will instrument the
1861 code with them to make this happen.
1862
ed53a0d9 1863 In addition to building the kernel with IBT, seal all functions that
4cdfc11b 1864 are not indirect call targets, avoiding them ever becoming one.
ed53a0d9
PZ
1865
1866 This requires LTO like objtool runs and will slow down the build. It
1867 does significantly reduce the number of ENDBR instructions in the
1868 kernel image.
1869
35e97790 1870config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1871 prompt "Memory Protection Keys"
35e97790 1872 def_bool y
284244a9 1873 # Note: only available in 64-bit mode
38f3e775 1874 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1875 select ARCH_USES_HIGH_VMA_FLAGS
1876 select ARCH_HAS_PKEYS
a7f7f624 1877 help
284244a9
DH
1878 Memory Protection Keys provides a mechanism for enforcing
1879 page-based protections, but without requiring modification of the
1880 page tables when an application changes protection domains.
1881
1eecbcdc 1882 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1883
1884 If unsure, say y.
35e97790 1885
db616173
MH
1886choice
1887 prompt "TSX enable mode"
1888 depends on CPU_SUP_INTEL
1889 default X86_INTEL_TSX_MODE_OFF
1890 help
1891 Intel's TSX (Transactional Synchronization Extensions) feature
1892 allows to optimize locking protocols through lock elision which
1893 can lead to a noticeable performance boost.
1894
1895 On the other hand it has been shown that TSX can be exploited
1896 to form side channel attacks (e.g. TAA) and chances are there
1897 will be more of those attacks discovered in the future.
1898
1899 Therefore TSX is not enabled by default (aka tsx=off). An admin
1900 might override this decision by tsx=on the command line parameter.
1901 Even with TSX enabled, the kernel will attempt to enable the best
1902 possible TAA mitigation setting depending on the microcode available
1903 for the particular machine.
1904
1905 This option allows to set the default tsx mode between tsx=on, =off
1906 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1907 details.
1908
1909 Say off if not sure, auto if TSX is in use but it should be used on safe
1910 platforms or on if TSX is in use and the security aspect of tsx is not
1911 relevant.
1912
1913config X86_INTEL_TSX_MODE_OFF
1914 bool "off"
1915 help
1916 TSX is disabled if possible - equals to tsx=off command line parameter.
1917
1918config X86_INTEL_TSX_MODE_ON
1919 bool "on"
1920 help
1921 TSX is always enabled on TSX capable HW - equals the tsx=on command
1922 line parameter.
1923
1924config X86_INTEL_TSX_MODE_AUTO
1925 bool "auto"
1926 help
1927 TSX is enabled on TSX capable HW that is believed to be safe against
1928 side channel attacks- equals the tsx=auto command line parameter.
1929endchoice
1930
e7e05452
SC
1931config X86_SGX
1932 bool "Software Guard eXtensions (SGX)"
b8d1d163 1933 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
e7e05452
SC
1934 depends on CRYPTO=y
1935 depends on CRYPTO_SHA256=y
e7e05452 1936 select MMU_NOTIFIER
901ddbb9 1937 select NUMA_KEEP_MEMINFO if NUMA
40e0e784 1938 select XARRAY_MULTI
e7e05452
SC
1939 help
1940 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1941 that can be used by applications to set aside private regions of code
1942 and data, referred to as enclaves. An enclave's private memory can
1943 only be accessed by code running within the enclave. Accesses from
1944 outside the enclave, including other enclaves, are disallowed by
1945 hardware.
1946
1947 If unsure, say N.
1948
18e66b69
RE
1949config X86_USER_SHADOW_STACK
1950 bool "X86 userspace shadow stack"
1951 depends on AS_WRUSS
1952 depends on X86_64
1953 select ARCH_USES_HIGH_VMA_FLAGS
1954 select X86_CET
1955 help
1956 Shadow stack protection is a hardware feature that detects function
1957 return address corruption. This helps mitigate ROP attacks.
1958 Applications must be enabled to use it, and old userspace does not
1959 get protection "for free".
1960
1961 CPUs supporting shadow stacks were first released in 2020.
1962
54acee60 1963 See Documentation/arch/x86/shstk.rst for more information.
18e66b69
RE
1964
1965 If unsure, say N.
1966
c33621b4
KH
1967config INTEL_TDX_HOST
1968 bool "Intel Trust Domain Extensions (TDX) host support"
1969 depends on CPU_SUP_INTEL
1970 depends on X86_64
1971 depends on KVM_INTEL
3115cabd 1972 depends on X86_X2APIC
abe8dbab 1973 select ARCH_KEEP_MEMBLOCK
ac3a2208 1974 depends on CONTIG_ALLOC
cb8eb06d 1975 depends on !KEXEC_CORE
83e1bdc9 1976 depends on X86_MCE
c33621b4
KH
1977 help
1978 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1979 host and certain physical attacks. This option enables necessary TDX
1980 support in the host kernel to run confidential VMs.
1981
1982 If unsure, say N.
1983
506f1d07 1984config EFI
9ba16087 1985 bool "EFI runtime service support"
5b83683f 1986 depends on ACPI
f6ce5002 1987 select UCS2_STRING
022ee6c5 1988 select EFI_RUNTIME_WRAPPERS
1ff2fc02 1989 select ARCH_USE_MEMREMAP_PROT
aba7e066 1990 select EFI_RUNTIME_MAP if KEXEC_CORE
a7f7f624 1991 help
8f9ca475
IM
1992 This enables the kernel to use EFI runtime services that are
1993 available (such as the EFI variable services).
506f1d07 1994
8f9ca475
IM
1995 This option is only useful on systems that have EFI firmware.
1996 In addition, you should use the latest ELILO loader available
1997 at <http://elilo.sourceforge.net> in order to take advantage
1998 of EFI runtime services. However, even with this option, the
1999 resultant kernel should continue to boot on existing non-EFI
2000 platforms.
506f1d07 2001
291f3632 2002config EFI_STUB
8f24f8c2 2003 bool "EFI stub support"
c6dbd3e5 2004 depends on EFI
8f24f8c2 2005 select RELOCATABLE
a7f7f624 2006 help
8f24f8c2 2007 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
2008 by EFI firmware without the use of a bootloader.
2009
4f4cfa6c 2010 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 2011
cc3fdda2
AB
2012config EFI_HANDOVER_PROTOCOL
2013 bool "EFI handover protocol (DEPRECATED)"
2014 depends on EFI_STUB
2015 default y
2016 help
2017 Select this in order to include support for the deprecated EFI
2018 handover protocol, which defines alternative entry points into the
2019 EFI stub. This is a practice that has no basis in the UEFI
2020 specification, and requires a priori knowledge on the part of the
2021 bootloader about Linux/x86 specific ways of passing the command line
2022 and initrd, and where in memory those assets may be loaded.
2023
2024 If in doubt, say Y. Even though the corresponding support is not
2025 present in upstream GRUB or other bootloaders, most distros build
2026 GRUB with numerous downstream patches applied, and may rely on the
2027 handover protocol as as result.
2028
7d453eee
MF
2029config EFI_MIXED
2030 bool "EFI mixed-mode support"
2031 depends on EFI_STUB && X86_64
a7f7f624 2032 help
758cd94a
JH
2033 Enabling this feature allows a 64-bit kernel to be booted
2034 on a 32-bit firmware, provided that your CPU supports 64-bit
2035 mode.
7d453eee 2036
758cd94a
JH
2037 Note that it is not possible to boot a mixed-mode enabled
2038 kernel via the EFI boot stub - a bootloader that supports
2039 the EFI handover protocol must be used.
7d453eee 2040
758cd94a 2041 If unsure, say N.
7d453eee 2042
4059ba65
AB
2043config EFI_FAKE_MEMMAP
2044 bool "Enable EFI fake memory map"
2045 depends on EFI
2046 help
2047 Saying Y here will enable "efi_fake_mem" boot option. By specifying
2048 this parameter, you can add arbitrary attribute to specific memory
2049 range by updating original (firmware provided) EFI memmap. This is
2050 useful for debugging of EFI memmap related feature, e.g., Address
2051 Range Mirroring feature.
2052
2053config EFI_MAX_FAKE_MEM
2054 int "maximum allowable number of ranges in efi_fake_mem boot option"
2055 depends on EFI_FAKE_MEMMAP
2056 range 1 128
2057 default 8
2058 help
2059 Maximum allowable number of ranges in efi_fake_mem boot option.
2060 Ranges can be set up to this value using comma-separated list.
2061 The default value is 8.
2062
1fff234d
AB
2063config EFI_RUNTIME_MAP
2064 bool "Export EFI runtime maps to sysfs" if EXPERT
2065 depends on EFI
1fff234d
AB
2066 help
2067 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2068 That memory map is required by the 2nd kernel to set up EFI virtual
2069 mappings after kexec, but can also be used for debugging purposes.
2070
2071 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2072
8636a1f9 2073source "kernel/Kconfig.hz"
506f1d07 2074
6af51380
ED
2075config ARCH_SUPPORTS_KEXEC
2076 def_bool y
74ca317c 2077
6af51380 2078config ARCH_SUPPORTS_KEXEC_FILE
c1ad12ee 2079 def_bool X86_64
b799a09f 2080
6af51380
ED
2081config ARCH_SELECTS_KEXEC_FILE
2082 def_bool y
74ca317c 2083 depends on KEXEC_FILE
6af51380 2084 select HAVE_IMA_KEXEC if IMA
d8eb8940 2085
e6265fe7 2086config ARCH_SUPPORTS_KEXEC_PURGATORY
c1ad12ee 2087 def_bool y
99d5cadf 2088
6af51380
ED
2089config ARCH_SUPPORTS_KEXEC_SIG
2090 def_bool y
8e7d8381 2091
6af51380
ED
2092config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2093 def_bool y
99d5cadf 2094
6af51380
ED
2095config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2096 def_bool y
8e7d8381 2097
6af51380
ED
2098config ARCH_SUPPORTS_KEXEC_JUMP
2099 def_bool y
506f1d07 2100
6af51380
ED
2101config ARCH_SUPPORTS_CRASH_DUMP
2102 def_bool X86_64 || (X86_32 && HIGHMEM)
3ab83521 2103
ea53ad9c
ED
2104config ARCH_SUPPORTS_CRASH_HOTPLUG
2105 def_bool y
3ab83521 2106
9c08a2a1
BH
2107config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2108 def_bool CRASH_CORE
2109
506f1d07 2110config PHYSICAL_START
6a108a14 2111 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2112 default "0x1000000"
a7f7f624 2113 help
506f1d07
SR
2114 This gives the physical address where the kernel is loaded.
2115
2116 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2117 bzImage will decompress itself to above physical address and
2118 run from there. Otherwise, bzImage will run from the address where
2119 it has been loaded by the boot loader and will ignore above physical
2120 address.
2121
2122 In normal kdump cases one does not have to set/change this option
2123 as now bzImage can be compiled as a completely relocatable image
2124 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2125 address. This option is mainly useful for the folks who don't want
2126 to use a bzImage for capturing the crash dump and want to use a
2127 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2128 to be specifically compiled to run from a specific memory area
2129 (normally a reserved region) and this option comes handy.
2130
ceefccc9
PA
2131 So if you are using bzImage for capturing the crash dump,
2132 leave the value here unchanged to 0x1000000 and set
2133 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2134 for capturing the crash dump change this value to start of
2135 the reserved region. In other words, it can be set based on
2136 the "X" value as specified in the "crashkernel=YM@XM"
2137 command line boot parameter passed to the panic-ed
330d4810 2138 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2139 for more details about crash dumps.
506f1d07
SR
2140
2141 Usage of bzImage for capturing the crash dump is recommended as
2142 one does not have to build two kernels. Same kernel can be used
2143 as production kernel and capture kernel. Above option should have
2144 gone away after relocatable bzImage support is introduced. But it
2145 is present because there are users out there who continue to use
2146 vmlinux for dump capture. This option should go away down the
2147 line.
2148
2149 Don't change this unless you know what you are doing.
2150
2151config RELOCATABLE
26717808
PA
2152 bool "Build a relocatable kernel"
2153 default y
a7f7f624 2154 help
506f1d07
SR
2155 This builds a kernel image that retains relocation information
2156 so it can be loaded someplace besides the default 1MB.
2157 The relocations tend to make the kernel binary about 10% larger,
2158 but are discarded at runtime.
2159
2160 One use is for the kexec on panic case where the recovery kernel
2161 must live at a different physical address than the primary
2162 kernel.
2163
2164 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2165 it has been loaded at and the compile time physical address
8ab3820f 2166 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2167
8ab3820f 2168config RANDOMIZE_BASE
e8581e3d 2169 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2170 depends on RELOCATABLE
6807c846 2171 default y
a7f7f624 2172 help
e8581e3d
BH
2173 In support of Kernel Address Space Layout Randomization (KASLR),
2174 this randomizes the physical address at which the kernel image
2175 is decompressed and the virtual address where the kernel
2176 image is mapped, as a security feature that deters exploit
2177 attempts relying on knowledge of the location of kernel
2178 code internals.
2179
ed9f007e
KC
2180 On 64-bit, the kernel physical and virtual addresses are
2181 randomized separately. The physical address will be anywhere
2182 between 16MB and the top of physical memory (up to 64TB). The
2183 virtual address will be randomized from 16MB up to 1GB (9 bits
2184 of entropy). Note that this also reduces the memory space
2185 available to kernel modules from 1.5GB to 1GB.
2186
2187 On 32-bit, the kernel physical and virtual addresses are
2188 randomized together. They will be randomized from 16MB up to
2189 512MB (8 bits of entropy).
e8581e3d
BH
2190
2191 Entropy is generated using the RDRAND instruction if it is
2192 supported. If RDTSC is supported, its value is mixed into
2193 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2194 supported, then entropy is read from the i8254 timer. The
2195 usable entropy is limited by the kernel being built using
2196 2GB addressing, and that PHYSICAL_ALIGN must be at a
2197 minimum of 2MB. As a result, only 10 bits of entropy are
2198 theoretically possible, but the implementations are further
2199 limited due to memory layouts.
e8581e3d 2200
6807c846 2201 If unsure, say Y.
8ab3820f
KC
2202
2203# Relocation on x86 needs some additional build support
845adf72
PA
2204config X86_NEED_RELOCS
2205 def_bool y
8ab3820f 2206 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2207
506f1d07 2208config PHYSICAL_ALIGN
a0215061 2209 hex "Alignment value to which kernel should be aligned"
8ab3820f 2210 default "0x200000"
a0215061
KC
2211 range 0x2000 0x1000000 if X86_32
2212 range 0x200000 0x1000000 if X86_64
a7f7f624 2213 help
506f1d07
SR
2214 This value puts the alignment restrictions on physical address
2215 where kernel is loaded and run from. Kernel is compiled for an
2216 address which meets above alignment restriction.
2217
2218 If bootloader loads the kernel at a non-aligned address and
2219 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2220 address aligned to above value and run from there.
2221
2222 If bootloader loads the kernel at a non-aligned address and
2223 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2224 load address and decompress itself to the address it has been
2225 compiled for and run from there. The address for which kernel is
2226 compiled already meets above alignment restrictions. Hence the
2227 end result is that kernel runs from a physical address meeting
2228 above alignment restrictions.
2229
a0215061
KC
2230 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2231 this value must be a multiple of 0x200000.
2232
506f1d07
SR
2233 Don't change this unless you know what you are doing.
2234
eedb92ab
KS
2235config DYNAMIC_MEMORY_LAYOUT
2236 bool
a7f7f624 2237 help
eedb92ab
KS
2238 This option makes base addresses of vmalloc and vmemmap as well as
2239 __PAGE_OFFSET movable during boot.
2240
0483e1fa
TG
2241config RANDOMIZE_MEMORY
2242 bool "Randomize the kernel memory sections"
2243 depends on X86_64
2244 depends on RANDOMIZE_BASE
eedb92ab 2245 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2246 default RANDOMIZE_BASE
a7f7f624 2247 help
758cd94a
JH
2248 Randomizes the base virtual address of kernel memory sections
2249 (physical memory mapping, vmalloc & vmemmap). This security feature
2250 makes exploits relying on predictable memory locations less reliable.
0483e1fa 2251
758cd94a
JH
2252 The order of allocations remains unchanged. Entropy is generated in
2253 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2254 configuration have in average 30,000 different possible virtual
2255 addresses for each memory section.
0483e1fa 2256
758cd94a 2257 If unsure, say Y.
0483e1fa 2258
90397a41
TG
2259config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2260 hex "Physical memory mapping padding" if EXPERT
2261 depends on RANDOMIZE_MEMORY
2262 default "0xa" if MEMORY_HOTPLUG
2263 default "0x0"
2264 range 0x1 0x40 if MEMORY_HOTPLUG
2265 range 0x0 0x40
a7f7f624 2266 help
758cd94a
JH
2267 Define the padding in terabytes added to the existing physical
2268 memory size during kernel memory randomization. It is useful
2269 for memory hotplug support but reduces the entropy available for
2270 address randomization.
90397a41 2271
758cd94a 2272 If unsure, leave at the default value.
90397a41 2273
6449dcb0
KS
2274config ADDRESS_MASKING
2275 bool "Linear Address Masking support"
2276 depends on X86_64
2277 help
2278 Linear Address Masking (LAM) modifies the checking that is applied
2279 to 64-bit linear addresses, allowing software to use of the
2280 untranslated address bits for metadata.
2281
2282 The capability can be used for efficient address sanitizers (ASAN)
2283 implementation and for optimizations in JITs.
2284
506f1d07 2285config HOTPLUG_CPU
bebd024e 2286 def_bool y
40b31360 2287 depends on SMP
506f1d07
SR
2288
2289config COMPAT_VDSO
b0b49f26
AL
2290 def_bool n
2291 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2292 depends on COMPAT_32
a7f7f624 2293 help
b0b49f26
AL
2294 Certain buggy versions of glibc will crash if they are
2295 presented with a 32-bit vDSO that is not mapped at the address
2296 indicated in its segment table.
e84446de 2297
b0b49f26
AL
2298 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2299 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2300 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2301 the only released version with the bug, but OpenSUSE 9
2302 contains a buggy "glibc 2.3.2".
506f1d07 2303
b0b49f26
AL
2304 The symptom of the bug is that everything crashes on startup, saying:
2305 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2306
2307 Saying Y here changes the default value of the vdso32 boot
2308 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2309 This works around the glibc bug but hurts performance.
2310
2311 If unsure, say N: if you are compiling your own kernel, you
2312 are unlikely to be using a buggy version of glibc.
506f1d07 2313
3dc33bd3
KC
2314choice
2315 prompt "vsyscall table for legacy applications"
2316 depends on X86_64
625b7b7f 2317 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2318 help
2319 Legacy user code that does not know how to find the vDSO expects
2320 to be able to issue three syscalls by calling fixed addresses in
2321 kernel space. Since this location is not randomized with ASLR,
2322 it can be used to assist security vulnerability exploitation.
2323
2324 This setting can be changed at boot time via the kernel command
bf00745e
AL
2325 line parameter vsyscall=[emulate|xonly|none]. Emulate mode
2326 is deprecated and can only be enabled using the kernel command
2327 line.
3dc33bd3
KC
2328
2329 On a system with recent enough glibc (2.14 or newer) and no
2330 static binaries, you can say None without a performance penalty
2331 to improve security.
2332
bd49e16e 2333 If unsure, select "Emulate execution only".
3dc33bd3 2334
bd49e16e
AL
2335 config LEGACY_VSYSCALL_XONLY
2336 bool "Emulate execution only"
2337 help
2338 The kernel traps and emulates calls into the fixed vsyscall
2339 address mapping and does not allow reads. This
2340 configuration is recommended when userspace might use the
2341 legacy vsyscall area but support for legacy binary
2342 instrumentation of legacy code is not needed. It mitigates
2343 certain uses of the vsyscall area as an ASLR-bypassing
2344 buffer.
3dc33bd3
KC
2345
2346 config LEGACY_VSYSCALL_NONE
2347 bool "None"
2348 help
2349 There will be no vsyscall mapping at all. This will
2350 eliminate any risk of ASLR bypass due to the vsyscall
2351 fixed address mapping. Attempts to use the vsyscalls
2352 will be reported to dmesg, so that either old or
2353 malicious userspace programs can be identified.
2354
2355endchoice
2356
516cbf37
TB
2357config CMDLINE_BOOL
2358 bool "Built-in kernel command line"
a7f7f624 2359 help
516cbf37
TB
2360 Allow for specifying boot arguments to the kernel at
2361 build time. On some systems (e.g. embedded ones), it is
2362 necessary or convenient to provide some or all of the
2363 kernel boot arguments with the kernel itself (that is,
2364 to not rely on the boot loader to provide them.)
2365
2366 To compile command line arguments into the kernel,
2367 set this option to 'Y', then fill in the
69711ca1 2368 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2369
2370 Systems with fully functional boot loaders (i.e. non-embedded)
2371 should leave this option set to 'N'.
2372
2373config CMDLINE
2374 string "Built-in kernel command string"
2375 depends on CMDLINE_BOOL
2376 default ""
a7f7f624 2377 help
516cbf37
TB
2378 Enter arguments here that should be compiled into the kernel
2379 image and used at boot time. If the boot loader provides a
2380 command line at boot time, it is appended to this string to
2381 form the full kernel command line, when the system boots.
2382
2383 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2384 change this behavior.
2385
2386 In most cases, the command line (whether built-in or provided
2387 by the boot loader) should specify the device for the root
2388 file system.
2389
2390config CMDLINE_OVERRIDE
2391 bool "Built-in command line overrides boot loader arguments"
645e6466 2392 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2393 help
516cbf37
TB
2394 Set this option to 'Y' to have the kernel ignore the boot loader
2395 command line, and use ONLY the built-in command line.
2396
2397 This is used to work around broken boot loaders. This should
2398 be set to 'N' under normal conditions.
2399
a5b9e5a2
AL
2400config MODIFY_LDT_SYSCALL
2401 bool "Enable the LDT (local descriptor table)" if EXPERT
2402 default y
a7f7f624 2403 help
a5b9e5a2
AL
2404 Linux can allow user programs to install a per-process x86
2405 Local Descriptor Table (LDT) using the modify_ldt(2) system
2406 call. This is required to run 16-bit or segmented code such as
2407 DOSEMU or some Wine programs. It is also used by some very old
2408 threading libraries.
2409
2410 Enabling this feature adds a small amount of overhead to
2411 context switches and increases the low-level kernel attack
2412 surface. Disabling it removes the modify_ldt(2) system call.
2413
2414 Saying 'N' here may make sense for embedded or server kernels.
2415
3aac3ebe
TG
2416config STRICT_SIGALTSTACK_SIZE
2417 bool "Enforce strict size checking for sigaltstack"
2418 depends on DYNAMIC_SIGFRAME
2419 help
2420 For historical reasons MINSIGSTKSZ is a constant which became
2421 already too small with AVX512 support. Add a mechanism to
2422 enforce strict checking of the sigaltstack size against the
2423 real size of the FPU frame. This option enables the check
2424 by default. It can also be controlled via the kernel command
2425 line option 'strict_sas_size' independent of this config
2426 switch. Enabling it might break existing applications which
2427 allocate a too small sigaltstack but 'work' because they
2428 never get a signal delivered.
2429
2430 Say 'N' unless you want to really enforce this check.
2431
b700e7f0
SJ
2432source "kernel/livepatch/Kconfig"
2433
506f1d07
SR
2434endmenu
2435
f43b9876
PZ
2436config CC_HAS_SLS
2437 def_bool $(cc-option,-mharden-sls=all)
2438
2439config CC_HAS_RETURN_THUNK
2440 def_bool $(cc-option,-mfunction-return=thunk-extern)
2441
bea75b33
TG
2442config CC_HAS_ENTRY_PADDING
2443 def_bool $(cc-option,-fpatchable-function-entry=16,16)
2444
2445config FUNCTION_PADDING_CFI
2446 int
2447 default 59 if FUNCTION_ALIGNMENT_64B
2448 default 27 if FUNCTION_ALIGNMENT_32B
2449 default 11 if FUNCTION_ALIGNMENT_16B
2450 default 3 if FUNCTION_ALIGNMENT_8B
2451 default 0
2452
2453# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2454# except Kconfig can't do arithmetic :/
2455config FUNCTION_PADDING_BYTES
2456 int
2457 default FUNCTION_PADDING_CFI if CFI_CLANG
2458 default FUNCTION_ALIGNMENT
2459
931ab636
PZ
2460config CALL_PADDING
2461 def_bool n
2462 depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2463 select FUNCTION_ALIGNMENT_16B
2464
2465config FINEIBT
2466 def_bool y
2467 depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE
2468 select CALL_PADDING
2469
8f7c0d8b
TG
2470config HAVE_CALL_THUNKS
2471 def_bool y
bea75b33 2472 depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
8f7c0d8b
TG
2473
2474config CALL_THUNKS
2475 def_bool n
931ab636 2476 select CALL_PADDING
8f7c0d8b 2477
b341b20d
PZ
2478config PREFIX_SYMBOLS
2479 def_bool y
931ab636 2480 depends on CALL_PADDING && !CFI_CLANG
b341b20d 2481
f43b9876
PZ
2482menuconfig SPECULATION_MITIGATIONS
2483 bool "Mitigations for speculative execution vulnerabilities"
2484 default y
2485 help
2486 Say Y here to enable options which enable mitigations for
2487 speculative execution hardware vulnerabilities.
2488
2489 If you say N, all mitigations will be disabled. You really
2490 should know what you are doing to say so.
2491
2492if SPECULATION_MITIGATIONS
2493
2494config PAGE_TABLE_ISOLATION
2495 bool "Remove the kernel mapping in user mode"
2496 default y
2497 depends on (X86_64 || X86_PAE)
2498 help
2499 This feature reduces the number of hardware side channels by
2500 ensuring that the majority of kernel addresses are not mapped
2501 into userspace.
2502
ff61f079 2503 See Documentation/arch/x86/pti.rst for more details.
f43b9876
PZ
2504
2505config RETPOLINE
2506 bool "Avoid speculative indirect branches in kernel"
2507 select OBJTOOL if HAVE_OBJTOOL
2508 default y
2509 help
2510 Compile kernel with the retpoline compiler options to guard against
2511 kernel-to-user data leaks by avoiding speculative indirect
2512 branches. Requires a compiler with -mindirect-branch=thunk-extern
2513 support for full protection. The kernel may run slower.
2514
2515config RETHUNK
2516 bool "Enable return-thunks"
2517 depends on RETPOLINE && CC_HAS_RETURN_THUNK
2518 select OBJTOOL if HAVE_OBJTOOL
b648ab48 2519 default y if X86_64
f43b9876
PZ
2520 help
2521 Compile the kernel with the return-thunks compiler option to guard
2522 against kernel-to-user data leaks by avoiding return speculation.
2523 Requires a compiler with -mfunction-return=thunk-extern
2524 support for full protection. The kernel may run slower.
2525
2526config CPU_UNRET_ENTRY
2527 bool "Enable UNRET on kernel entry"
b648ab48 2528 depends on CPU_SUP_AMD && RETHUNK && X86_64
f43b9876
PZ
2529 default y
2530 help
2531 Compile the kernel with support for the retbleed=unret mitigation.
2532
80e4c1cd
TG
2533config CALL_DEPTH_TRACKING
2534 bool "Mitigate RSB underflow with call depth tracking"
2535 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2536 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2537 select CALL_THUNKS
2538 default y
2539 help
2540 Compile the kernel with call depth tracking to mitigate the Intel
2541 SKL Return-Speculation-Buffer (RSB) underflow issue. The
2542 mitigation is off by default and needs to be enabled on the
2543 kernel command line via the retbleed=stuff option. For
2544 non-affected systems the overhead of this option is marginal as
2545 the call depth tracking is using run-time generated call thunks
2546 in a compiler generated padding area and call patching. This
2547 increases text size by ~5%. For non affected systems this space
2548 is unused. On affected SKL systems this results in a significant
2549 performance gain over the IBRS mitigation.
2550
e81dc127
TG
2551config CALL_THUNKS_DEBUG
2552 bool "Enable call thunks and call depth tracking debugging"
2553 depends on CALL_DEPTH_TRACKING
2554 select FUNCTION_ALIGNMENT_32B
2555 default n
2556 help
2557 Enable call/ret counters for imbalance detection and build in
2558 a noisy dmesg about callthunks generation and call patching for
2559 trouble shooting. The debug prints need to be enabled on the
2560 kernel command line with 'debug-callthunks'.
54628de6
RD
2561 Only enable this when you are debugging call thunks as this
2562 creates a noticeable runtime overhead. If unsure say N.
80e4c1cd 2563
f43b9876
PZ
2564config CPU_IBPB_ENTRY
2565 bool "Enable IBPB on kernel entry"
b648ab48 2566 depends on CPU_SUP_AMD && X86_64
f43b9876
PZ
2567 default y
2568 help
2569 Compile the kernel with support for the retbleed=ibpb mitigation.
2570
2571config CPU_IBRS_ENTRY
2572 bool "Enable IBRS on kernel entry"
b648ab48 2573 depends on CPU_SUP_INTEL && X86_64
f43b9876
PZ
2574 default y
2575 help
2576 Compile the kernel with support for the spectre_v2=ibrs mitigation.
2577 This mitigates both spectre_v2 and retbleed at great cost to
2578 performance.
2579
fb3bd914
BPA
2580config CPU_SRSO
2581 bool "Mitigate speculative RAS overflow on AMD"
2582 depends on CPU_SUP_AMD && X86_64 && RETHUNK
2583 default y
2584 help
2585 Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2586
f43b9876
PZ
2587config SLS
2588 bool "Mitigate Straight-Line-Speculation"
2589 depends on CC_HAS_SLS && X86_64
2590 select OBJTOOL if HAVE_OBJTOOL
2591 default n
2592 help
2593 Compile the kernel with straight-line-speculation options to guard
2594 against straight line speculation. The kernel image might be slightly
2595 larger.
2596
53cf5797
DS
2597config GDS_FORCE_MITIGATION
2598 bool "Force GDS Mitigation"
2599 depends on CPU_SUP_INTEL
2600 default n
2601 help
2602 Gather Data Sampling (GDS) is a hardware vulnerability which allows
2603 unprivileged speculative access to data which was previously stored in
2604 vector registers.
2605
2606 This option is equivalent to setting gather_data_sampling=force on the
2607 command line. The microcode mitigation is used if present, otherwise
2608 AVX is disabled as a mitigation. On affected systems that are missing
2609 the microcode any userspace code that unconditionally uses AVX will
2610 break with this option set.
2611
2612 Setting this option on systems not vulnerable to GDS has no effect.
2613
2614 If in doubt, say N.
2615
f43b9876
PZ
2616endif
2617
3072e413
MH
2618config ARCH_HAS_ADD_PAGES
2619 def_bool y
5c11f00b 2620 depends on ARCH_ENABLE_MEMORY_HOTPLUG
3072e413 2621
da85f865 2622menu "Power management and ACPI options"
e279b6c1
SR
2623
2624config ARCH_HIBERNATION_HEADER
3c2362e6 2625 def_bool y
44556530 2626 depends on HIBERNATION
e279b6c1
SR
2627
2628source "kernel/power/Kconfig"
2629
2630source "drivers/acpi/Kconfig"
2631
a6b68076 2632config X86_APM_BOOT
6fc108a0 2633 def_bool y
282e5aab 2634 depends on APM
a6b68076 2635
e279b6c1
SR
2636menuconfig APM
2637 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2638 depends on X86_32 && PM_SLEEP
a7f7f624 2639 help
e279b6c1
SR
2640 APM is a BIOS specification for saving power using several different
2641 techniques. This is mostly useful for battery powered laptops with
2642 APM compliant BIOSes. If you say Y here, the system time will be
2643 reset after a RESUME operation, the /proc/apm device will provide
2644 battery status information, and user-space programs will receive
2645 notification of APM "events" (e.g. battery status change).
2646
2647 If you select "Y" here, you can disable actual use of the APM
2648 BIOS by passing the "apm=off" option to the kernel at boot time.
2649
2650 Note that the APM support is almost completely disabled for
2651 machines with more than one CPU.
2652
2653 In order to use APM, you will need supporting software. For location
151f4e2b 2654 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2655 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2656 <http://www.tldp.org/docs.html#howto>.
2657
2658 This driver does not spin down disk drives (see the hdparm(8)
2659 manpage ("man 8 hdparm") for that), and it doesn't turn off
2660 VESA-compliant "green" monitors.
2661
2662 This driver does not support the TI 4000M TravelMate and the ACER
2663 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2664 desktop machines also don't have compliant BIOSes, and this driver
2665 may cause those machines to panic during the boot phase.
2666
2667 Generally, if you don't have a battery in your machine, there isn't
2668 much point in using this driver and you should say N. If you get
2669 random kernel OOPSes or reboots that don't seem to be related to
2670 anything, try disabling/enabling this option (or disabling/enabling
2671 APM in your BIOS).
2672
2673 Some other things you should try when experiencing seemingly random,
2674 "weird" problems:
2675
2676 1) make sure that you have enough swap space and that it is
2677 enabled.
7987448f 2678 2) pass the "idle=poll" option to the kernel
e279b6c1
SR
2679 3) switch on floating point emulation in the kernel and pass
2680 the "no387" option to the kernel
2681 4) pass the "floppy=nodma" option to the kernel
2682 5) pass the "mem=4M" option to the kernel (thereby disabling
2683 all but the first 4 MB of RAM)
2684 6) make sure that the CPU is not over clocked.
2685 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2686 8) disable the cache from your BIOS settings
2687 9) install a fan for the video card or exchange video RAM
2688 10) install a better fan for the CPU
2689 11) exchange RAM chips
2690 12) exchange the motherboard.
2691
2692 To compile this driver as a module, choose M here: the
2693 module will be called apm.
2694
2695if APM
2696
2697config APM_IGNORE_USER_SUSPEND
2698 bool "Ignore USER SUSPEND"
a7f7f624 2699 help
e279b6c1
SR
2700 This option will ignore USER SUSPEND requests. On machines with a
2701 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2702 series notebooks, it is necessary to say Y because of a BIOS bug.
2703
2704config APM_DO_ENABLE
2705 bool "Enable PM at boot time"
a7f7f624 2706 help
e279b6c1
SR
2707 Enable APM features at boot time. From page 36 of the APM BIOS
2708 specification: "When disabled, the APM BIOS does not automatically
2709 power manage devices, enter the Standby State, enter the Suspend
2710 State, or take power saving steps in response to CPU Idle calls."
2711 This driver will make CPU Idle calls when Linux is idle (unless this
2712 feature is turned off -- see "Do CPU IDLE calls", below). This
2713 should always save battery power, but more complicated APM features
2714 will be dependent on your BIOS implementation. You may need to turn
2715 this option off if your computer hangs at boot time when using APM
2716 support, or if it beeps continuously instead of suspending. Turn
2717 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2718 T400CDT. This is off by default since most machines do fine without
2719 this feature.
2720
2721config APM_CPU_IDLE
dd8af076 2722 depends on CPU_IDLE
e279b6c1 2723 bool "Make CPU Idle calls when idle"
a7f7f624 2724 help
e279b6c1
SR
2725 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2726 On some machines, this can activate improved power savings, such as
2727 a slowed CPU clock rate, when the machine is idle. These idle calls
2728 are made after the idle loop has run for some length of time (e.g.,
2729 333 mS). On some machines, this will cause a hang at boot time or
2730 whenever the CPU becomes idle. (On machines with more than one CPU,
2731 this option does nothing.)
2732
2733config APM_DISPLAY_BLANK
2734 bool "Enable console blanking using APM"
a7f7f624 2735 help
e279b6c1
SR
2736 Enable console blanking using the APM. Some laptops can use this to
2737 turn off the LCD backlight when the screen blanker of the Linux
2738 virtual console blanks the screen. Note that this is only used by
2739 the virtual console screen blanker, and won't turn off the backlight
2740 when using the X Window system. This also doesn't have anything to
2741 do with your VESA-compliant power-saving monitor. Further, this
2742 option doesn't work for all laptops -- it might not turn off your
2743 backlight at all, or it might print a lot of errors to the console,
2744 especially if you are using gpm.
2745
2746config APM_ALLOW_INTS
2747 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2748 help
e279b6c1
SR
2749 Normally we disable external interrupts while we are making calls to
2750 the APM BIOS as a measure to lessen the effects of a badly behaving
2751 BIOS implementation. The BIOS should reenable interrupts if it
2752 needs to. Unfortunately, some BIOSes do not -- especially those in
2753 many of the newer IBM Thinkpads. If you experience hangs when you
2754 suspend, try setting this to Y. Otherwise, say N.
2755
e279b6c1
SR
2756endif # APM
2757
bb0a56ec 2758source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2759
2760source "drivers/cpuidle/Kconfig"
2761
27471fdb
AH
2762source "drivers/idle/Kconfig"
2763
e279b6c1
SR
2764endmenu
2765
e279b6c1
SR
2766menu "Bus options (PCI etc.)"
2767
e279b6c1
SR
2768choice
2769 prompt "PCI access mode"
efefa6f6 2770 depends on X86_32 && PCI
e279b6c1 2771 default PCI_GOANY
a7f7f624 2772 help
e279b6c1
SR
2773 On PCI systems, the BIOS can be used to detect the PCI devices and
2774 determine their configuration. However, some old PCI motherboards
2775 have BIOS bugs and may crash if this is done. Also, some embedded
2776 PCI-based systems don't have any BIOS at all. Linux can also try to
2777 detect the PCI hardware directly without using the BIOS.
2778
2779 With this option, you can specify how Linux should detect the
2780 PCI devices. If you choose "BIOS", the BIOS will be used,
2781 if you choose "Direct", the BIOS won't be used, and if you
2782 choose "MMConfig", then PCI Express MMCONFIG will be used.
2783 If you choose "Any", the kernel will try MMCONFIG, then the
2784 direct access method and falls back to the BIOS if that doesn't
2785 work. If unsure, go with the default, which is "Any".
2786
2787config PCI_GOBIOS
2788 bool "BIOS"
2789
2790config PCI_GOMMCONFIG
2791 bool "MMConfig"
2792
2793config PCI_GODIRECT
2794 bool "Direct"
2795
3ef0e1f8 2796config PCI_GOOLPC
76fb6570 2797 bool "OLPC XO-1"
3ef0e1f8
AS
2798 depends on OLPC
2799
2bdd1b03
AS
2800config PCI_GOANY
2801 bool "Any"
2802
e279b6c1
SR
2803endchoice
2804
2805config PCI_BIOS
3c2362e6 2806 def_bool y
efefa6f6 2807 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2808
2809# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2810config PCI_DIRECT
3c2362e6 2811 def_bool y
0aba496f 2812 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2813
2814config PCI_MMCONFIG
b45c9f36
JK
2815 bool "Support mmconfig PCI config space access" if X86_64
2816 default y
4590d98f 2817 depends on PCI && (ACPI || JAILHOUSE_GUEST)
b45c9f36 2818 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2819
3ef0e1f8 2820config PCI_OLPC
2bdd1b03
AS
2821 def_bool y
2822 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2823
b5401a96
AN
2824config PCI_XEN
2825 def_bool y
2826 depends on PCI && XEN
b5401a96 2827
8364e1f8
JK
2828config MMCONF_FAM10H
2829 def_bool y
2830 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2831
3f6ea84a 2832config PCI_CNB20LE_QUIRK
6a108a14 2833 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2834 depends on PCI
3f6ea84a
IS
2835 help
2836 Read the PCI windows out of the CNB20LE host bridge. This allows
2837 PCI hotplug to work on systems with the CNB20LE chipset which do
2838 not have ACPI.
2839
64a5fed6
BH
2840 There's no public spec for this chipset, and this functionality
2841 is known to be incomplete.
2842
2843 You should say N unless you know you need this.
2844
3a495511 2845config ISA_BUS
17a2a129 2846 bool "ISA bus support on modern systems" if EXPERT
3a495511 2847 help
17a2a129
WBG
2848 Expose ISA bus device drivers and options available for selection and
2849 configuration. Enable this option if your target machine has an ISA
2850 bus. ISA is an older system, displaced by PCI and newer bus
2851 architectures -- if your target machine is modern, it probably does
2852 not have an ISA bus.
3a495511
WBG
2853
2854 If unsure, say N.
2855
1c00f016 2856# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2857config ISA_DMA_API
1c00f016
DR
2858 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2859 default y
2860 help
2861 Enables ISA-style DMA support for devices requiring such controllers.
2862 If unsure, say Y.
e279b6c1 2863
51e68d05
LT
2864if X86_32
2865
e279b6c1
SR
2866config ISA
2867 bool "ISA support"
a7f7f624 2868 help
e279b6c1
SR
2869 Find out whether you have ISA slots on your motherboard. ISA is the
2870 name of a bus system, i.e. the way the CPU talks to the other stuff
2871 inside your box. Other bus systems are PCI, EISA, MicroChannel
2872 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2873 newer boards don't support it. If you have ISA, say Y, otherwise N.
2874
e279b6c1
SR
2875config SCx200
2876 tristate "NatSemi SCx200 support"
a7f7f624 2877 help
e279b6c1
SR
2878 This provides basic support for National Semiconductor's
2879 (now AMD's) Geode processors. The driver probes for the
2880 PCI-IDs of several on-chip devices, so its a good dependency
2881 for other scx200_* drivers.
2882
2883 If compiled as a module, the driver is named scx200.
2884
2885config SCx200HR_TIMER
2886 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2887 depends on SCx200
e279b6c1 2888 default y
a7f7f624 2889 help
e279b6c1
SR
2890 This driver provides a clocksource built upon the on-chip
2891 27MHz high-resolution timer. Its also a workaround for
2892 NSC Geode SC-1100's buggy TSC, which loses time when the
2893 processor goes idle (as is done by the scheduler). The
2894 other workaround is idle=poll boot option.
2895
3ef0e1f8
AS
2896config OLPC
2897 bool "One Laptop Per Child support"
54008979 2898 depends on !X86_PAE
3c554946 2899 select GPIOLIB
dc3119e7 2900 select OF
45bb1674 2901 select OF_PROMTREE
b4e51854 2902 select IRQ_DOMAIN
0c3d931b 2903 select OLPC_EC
a7f7f624 2904 help
3ef0e1f8
AS
2905 Add support for detecting the unique features of the OLPC
2906 XO hardware.
2907
a3128588
DD
2908config OLPC_XO1_PM
2909 bool "OLPC XO-1 Power Management"
fa112cf1 2910 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 2911 help
97c4cb71 2912 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2913
cfee9597
DD
2914config OLPC_XO1_RTC
2915 bool "OLPC XO-1 Real Time Clock"
2916 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 2917 help
cfee9597
DD
2918 Add support for the XO-1 real time clock, which can be used as a
2919 programmable wakeup source.
2920
7feda8e9
DD
2921config OLPC_XO1_SCI
2922 bool "OLPC XO-1 SCI extras"
92e830f2 2923 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2924 depends on INPUT=y
d8d01a63 2925 select POWER_SUPPLY
a7f7f624 2926 help
7feda8e9 2927 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2928 - EC-driven system wakeups
7feda8e9 2929 - Power button
7bc74b3d 2930 - Ebook switch
2cf2baea 2931 - Lid switch
e1040ac6
DD
2932 - AC adapter status updates
2933 - Battery status updates
7feda8e9 2934
a0f30f59
DD
2935config OLPC_XO15_SCI
2936 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2937 depends on OLPC && ACPI
2938 select POWER_SUPPLY
a7f7f624 2939 help
a0f30f59
DD
2940 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2941 - EC-driven system wakeups
2942 - AC adapter status updates
2943 - Battery status updates
bf1ebf00 2944
d4f3e350
EW
2945config ALIX
2946 bool "PCEngines ALIX System Support (LED setup)"
2947 select GPIOLIB
a7f7f624 2948 help
d4f3e350
EW
2949 This option enables system support for the PCEngines ALIX.
2950 At present this just sets up LEDs for GPIO control on
2951 ALIX2/3/6 boards. However, other system specific setup should
2952 get added here.
2953
2954 Note: You must still enable the drivers for GPIO and LED support
2955 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2956
2957 Note: You have to set alix.force=1 for boards with Award BIOS.
2958
da4e3302
PP
2959config NET5501
2960 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2961 select GPIOLIB
a7f7f624 2962 help
da4e3302
PP
2963 This option enables system support for the Soekris Engineering net5501.
2964
3197059a
PP
2965config GEOS
2966 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2967 select GPIOLIB
2968 depends on DMI
a7f7f624 2969 help
3197059a
PP
2970 This option enables system support for the Traverse Technologies GEOS.
2971
7d029125
VD
2972config TS5500
2973 bool "Technologic Systems TS-5500 platform support"
2974 depends on MELAN
2975 select CHECK_SIGNATURE
2976 select NEW_LEDS
2977 select LEDS_CLASS
a7f7f624 2978 help
7d029125
VD
2979 This option enables system support for the Technologic Systems TS-5500.
2980
bc0120fd
SR
2981endif # X86_32
2982
23ac4ae8 2983config AMD_NB
e279b6c1 2984 def_bool y
0e152cd7 2985 depends on CPU_SUP_AMD && PCI
e279b6c1 2986
e279b6c1
SR
2987endmenu
2988
1572497c 2989menu "Binary Emulations"
e279b6c1
SR
2990
2991config IA32_EMULATION
2992 bool "IA32 Emulation"
2993 depends on X86_64
39f88911 2994 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2995 select BINFMT_ELF
39f88911 2996 select COMPAT_OLD_SIGACTION
a7f7f624 2997 help
5fd92e65
L
2998 Include code to run legacy 32-bit programs under a
2999 64-bit kernel. You should likely turn this on, unless you're
3000 100% sure that you don't have any 32-bit programs left.
e279b6c1 3001
a11e0975
NB
3002config IA32_EMULATION_DEFAULT_DISABLED
3003 bool "IA32 emulation disabled by default"
3004 default n
3005 depends on IA32_EMULATION
3006 help
3007 Make IA32 emulation disabled by default. This prevents loading 32-bit
3008 processes and access to 32-bit syscalls. If unsure, leave it to its
3009 default value.
3010
83a44a4f 3011config X86_X32_ABI
6ea30386 3012 bool "x32 ABI for 64-bit mode"
9b54050b 3013 depends on X86_64
aaeed6ec
NC
3014 # llvm-objcopy does not convert x86_64 .note.gnu.property or
3015 # compressed debug sections to x86_x32 properly:
3016 # https://github.com/ClangBuiltLinux/linux/issues/514
3017 # https://github.com/ClangBuiltLinux/linux/issues/1141
3018 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
a7f7f624 3019 help
5fd92e65
L
3020 Include code to run binaries for the x32 native 32-bit ABI
3021 for 64-bit processors. An x32 process gets access to the
3022 full 64-bit register file and wide data path while leaving
3023 pointers at 32 bits for smaller memory footprint.
3024
953fee1d
IM
3025config COMPAT_32
3026 def_bool y
3027 depends on IA32_EMULATION || X86_32
3028 select HAVE_UID16
3029 select OLD_SIGSUSPEND3
3030
e279b6c1 3031config COMPAT
3c2362e6 3032 def_bool y
83a44a4f 3033 depends on IA32_EMULATION || X86_X32_ABI
e279b6c1
SR
3034
3035config COMPAT_FOR_U64_ALIGNMENT
3120e25e 3036 def_bool y
a9251280 3037 depends on COMPAT
ee009e4a 3038
e279b6c1
SR
3039endmenu
3040
e5beae16
KP
3041config HAVE_ATOMIC_IOMAP
3042 def_bool y
3043 depends on X86_32
3044
edf88417 3045source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
3046
3047source "arch/x86/Kconfig.assembler"