compiler_attributes.h: cleanups for GCC 4.9+
[linux-2.6-block.git] / arch / x86 / Kconfig
CommitLineData
b2441318 1# SPDX-License-Identifier: GPL-2.0
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SR
2# Select 32 or 64 bit
3config 64BIT
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MY
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
a7f7f624 6 help
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SR
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
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JB
11 def_bool y
12 depends on !64BIT
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IM
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
15 select CLKSRC_I8253
16 select CLONE_BACKWARDS
157e118b 17 select GENERIC_VDSO_32
117ed454 18 select HAVE_DEBUG_STACKOVERFLOW
157e118b 19 select KMAP_LOCAL
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IM
20 select MODULES_USE_ELF_REL
21 select OLD_SIGACTION
2ca408d9 22 select ARCH_SPLIT_ARG64
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SR
23
24config X86_64
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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
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IM
30 select ARCH_USE_CMPXCHG_LOCKREF
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
1032c0ba 36
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SRV
37config FORCE_DYNAMIC_FTRACE
38 def_bool y
39 depends on X86_32
40 depends on FUNCTION_TRACER
41 select DYNAMIC_FTRACE
42 help
43 We keep the static function tracing (!DYNAMIC_FTRACE) around
44 in order to test the non static function tracing in the
45 generic code, as other architectures still use it. But we
46 only need to keep it around for x86_64. No need to keep it
47 for x86_32. For x86_32, force DYNAMIC_FTRACE.
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IM
48#
49# Arch settings
50#
51# ( Note that options that are marked 'if X86_64' could in principle be
52# ported to 32-bit as well. )
53#
8d5fffb9 54config X86
3c2362e6 55 def_bool y
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56 #
57 # Note: keep this list sorted alphabetically
58 #
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59 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
60 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
942fa985 61 select ARCH_32BIT_OFF_T if X86_32
2a21ad57 62 select ARCH_CLOCKSOURCE_INIT
1e866974 63 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
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AK
64 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 || (X86_32 && HIGHMEM)
65 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
66f24fa7 66 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if X86_64 || X86_PAE
1e866974 67 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
c763ea26 68 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
c2280be8 69 select ARCH_HAS_CACHE_LINE_SIZE
fa5b6ec9 70 select ARCH_HAS_DEBUG_VIRTUAL
399145f9 71 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
21266be9 72 select ARCH_HAS_DEVMEM_IS_ALLOWED
b1a57bbf 73 select ARCH_HAS_EARLY_DEBUG if KGDB
6471b825 74 select ARCH_HAS_ELF_RANDOMIZE
72d93104 75 select ARCH_HAS_FAST_MULTIPLIER
316d097c 76 select ARCH_HAS_FILTER_PGPROT
6974f0c4 77 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 78 select ARCH_HAS_GCOV_PROFILE_ALL
0f1441b4 79 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
0c9c1d56 80 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 81 select ARCH_HAS_MEMBARRIER_SYNC_CORE
0ebeea8c 82 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
c763ea26 83 select ARCH_HAS_PMEM_API if X86_64
17596731 84 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 85 select ARCH_HAS_PTE_SPECIAL
0aed55af 86 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
ec6347bb 87 select ARCH_HAS_COPY_MC if X86_64
d2852a22 88 select ARCH_HAS_SET_MEMORY
d253ca0c 89 select ARCH_HAS_SET_DIRECT_MAP
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LA
90 select ARCH_HAS_STRICT_KERNEL_RWX
91 select ARCH_HAS_STRICT_MODULE_RWX
ac1ab12a 92 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
25c619e5 93 select ARCH_HAS_SYSCALL_WRAPPER
c6d30853 94 select ARCH_HAS_UBSAN_SANITIZE_ALL
7e01ccb4 95 select ARCH_HAS_DEBUG_WX
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96 select ARCH_HAVE_NMI_SAFE_CMPXCHG
97 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 98 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 99 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 100 select ARCH_STACKWALK
2c870e61 101 select ARCH_SUPPORTS_ACPI
6471b825 102 select ARCH_SUPPORTS_ATOMIC_RMW
5d6ad668 103 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
6471b825 104 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
14df3267 105 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096
583bfd48
NC
106 select ARCH_SUPPORTS_LTO_CLANG
107 select ARCH_SUPPORTS_LTO_CLANG_THIN
6471b825 108 select ARCH_USE_BUILTIN_BSWAP
dce44566 109 select ARCH_USE_MEMTEST
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IM
110 select ARCH_USE_QUEUED_RWLOCKS
111 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 112 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 113 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 114 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 115 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
3876d4a3 116 select ARCH_WANT_HUGE_PMD_SHARE
59612b24 117 select ARCH_WANT_LD_ORPHAN_WARN
38d8b4e6 118 select ARCH_WANTS_THP_SWAP if X86_64
10916706 119 select BUILDTIME_TABLE_SORT
6471b825 120 select CLKEVT_I8253
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IM
121 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
122 select CLOCKSOURCE_WATCHDOG
6471b825 123 select DCACHE_WORD_ACCESS
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LT
124 select EDAC_ATOMIC_SCRUB
125 select EDAC_SUPPORT
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IM
126 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
127 select GENERIC_CLOCKEVENTS_MIN_ADJUST
128 select GENERIC_CMOS_UPDATE
129 select GENERIC_CPU_AUTOPROBE
61dc0f55 130 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 131 select GENERIC_EARLY_IOREMAP
27d6b4d1 132 select GENERIC_ENTRY
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IM
133 select GENERIC_FIND_FIRST_BIT
134 select GENERIC_IOMAP
c7d6c9dd 135 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 136 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 137 select GENERIC_IRQ_MIGRATION if SMP
6471b825 138 select GENERIC_IRQ_PROBE
c201c917 139 select GENERIC_IRQ_RESERVATION_MODE
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140 select GENERIC_IRQ_SHOW
141 select GENERIC_PENDING_IRQ if SMP
2ae27137 142 select GENERIC_PTDUMP
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143 select GENERIC_SMP_IDLE_THREAD
144 select GENERIC_STRNCPY_FROM_USER
145 select GENERIC_STRNLEN_USER
146 select GENERIC_TIME_VSYSCALL
7ac87074 147 select GENERIC_GETTIMEOFDAY
550a77a7 148 select GENERIC_VDSO_TIME_NS
39656e83 149 select GUP_GET_PTE_LOW_HIGH if X86_PAE
17e5888e 150 select HARDIRQS_SW_RESEND
7edaeb68 151 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
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152 select HAVE_ACPI_APEI if ACPI
153 select HAVE_ACPI_APEI_NMI if ACPI
154 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
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155 select HAVE_ARCH_AUDITSYSCALL
156 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
157 select HAVE_ARCH_JUMP_LABEL
b34006c4 158 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 159 select HAVE_ARCH_KASAN if X86_64
0609ae01 160 select HAVE_ARCH_KASAN_VMALLOC if X86_64
1dc0da6e 161 select HAVE_ARCH_KFENCE
6471b825 162 select HAVE_ARCH_KGDB
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DC
163 select HAVE_ARCH_MMAP_RND_BITS if MMU
164 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 165 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 166 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 167 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 168 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 169 select HAVE_ARCH_STACKLEAK
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IM
170 select HAVE_ARCH_TRACEHOOK
171 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 172 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 173 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
7677f7fd 174 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD
e37e43a4 175 select HAVE_ARCH_VMAP_STACK if X86_64
fe950f60 176 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
c763ea26 177 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 178 select HAVE_ASM_MODVERSIONS
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179 select HAVE_CMPXCHG_DOUBLE
180 select HAVE_CMPXCHG_LOCAL
181 select HAVE_CONTEXT_TRACKING if X86_64
d1f250e2 182 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING
cf4db259 183 select HAVE_C_RECORDMCOUNT
6dafca97 184 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION
6471b825 185 select HAVE_DEBUG_KMEMLEAK
6471b825 186 select HAVE_DMA_CONTIGUOUS
677aa9f7 187 select HAVE_DYNAMIC_FTRACE
06aeaaea 188 select HAVE_DYNAMIC_FTRACE_WITH_REGS
02a474ca 189 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64
562955fe 190 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
03f5781b 191 select HAVE_EBPF_JIT
58340a07 192 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 193 select HAVE_EISA
5f56a5df 194 select HAVE_EXIT_THREAD
67a929e0 195 select HAVE_FAST_GUP
644e0e8d 196 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 197 select HAVE_FTRACE_MCOUNT_RECORD
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198 select HAVE_FUNCTION_GRAPH_TRACER
199 select HAVE_FUNCTION_TRACER
6b90bd4b 200 select HAVE_GCC_PLUGINS
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201 select HAVE_HW_BREAKPOINT
202 select HAVE_IDE
203 select HAVE_IOREMAP_PROT
624db9ea 204 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
6471b825 205 select HAVE_IRQ_TIME_ACCOUNTING
2e9f3bdd 206 select HAVE_KERNEL_BZIP2
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IM
207 select HAVE_KERNEL_GZIP
208 select HAVE_KERNEL_LZ4
2e9f3bdd 209 select HAVE_KERNEL_LZMA
13510997 210 select HAVE_KERNEL_LZO
6471b825 211 select HAVE_KERNEL_XZ
fb46d057 212 select HAVE_KERNEL_ZSTD
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IM
213 select HAVE_KPROBES
214 select HAVE_KPROBES_ON_FTRACE
540adea3 215 select HAVE_FUNCTION_ERROR_INJECTION
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216 select HAVE_KRETPROBES
217 select HAVE_KVM
218 select HAVE_LIVEPATCH if X86_64
0102752e 219 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 220 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 221 select HAVE_MOVE_PMD
be37c98d 222 select HAVE_MOVE_PUD
42a0bb3f 223 select HAVE_NMI
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IM
224 select HAVE_OPTPROBES
225 select HAVE_PCSPKR_PLATFORM
226 select HAVE_PERF_EVENTS
c01d4323 227 select HAVE_PERF_EVENTS_NMI
92e5aae4 228 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 229 select HAVE_PCI
c5e63197 230 select HAVE_PERF_REGS
c5ebcedb 231 select HAVE_PERF_USER_STACK_DUMP
ff2e6d72 232 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
00998085 233 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 234 select HAVE_REGS_AND_STACK_ACCESS_API
6415b38b 235 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
3c88ee19 236 select HAVE_FUNCTION_ARG_ACCESS_API
cd1a41ce 237 select HAVE_SOFTIRQ_ON_OWN_STACK
d148eac0 238 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
c763ea26 239 select HAVE_STACK_VALIDATION if X86_64
e6d6c071 240 select HAVE_STATIC_CALL
1e7e4788 241 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
6ef869e0 242 select HAVE_PREEMPT_DYNAMIC
d6761b8f 243 select HAVE_RSEQ
6471b825 244 select HAVE_SYSCALL_TRACEPOINTS
6471b825 245 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 246 select HAVE_USER_RETURN_NOTIFIER
7ac87074 247 select HAVE_GENERIC_VDSO
05736e4a 248 select HOTPLUG_SMT if SMP
c0185808 249 select IRQ_FORCED_THREADING
86596f0a 250 select NEED_SG_DMA_LENGTH
2eac9c2d 251 select PCI_DOMAINS if PCI
625210cf 252 select PCI_LOCKLESS_CONFIG if PCI
6471b825 253 select PERF_EVENTS
3195ef59 254 select RTC_LIB
d6faca40 255 select RTC_MC146818_LIB
6471b825 256 select SPARSE_IRQ
83fe27ea 257 select SRCU
1e7e4788 258 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
6471b825 259 select SYSCTL_EXCEPTION_TRACE
15f4eae7 260 select THREAD_INFO_IN_TASK
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IM
261 select USER_STACKTRACE_SUPPORT
262 select VIRT_TO_BUS
3b02a051 263 select HAVE_ARCH_KCSAN if X86_64
6471b825 264 select X86_FEATURE_NAMES if PROC_FS
0c608dad 265 select PROC_PID_ARCH_STATUS if PROC_FS
9e2b4be3 266 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
7d8330a5 267
ba7e4d13 268config INSTRUCTION_DECODER
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JB
269 def_bool y
270 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 271
51b26ada
LT
272config OUTPUT_FORMAT
273 string
274 default "elf32-i386" if X86_32
275 default "elf64-x86-64" if X86_64
276
8d5fffb9 277config LOCKDEP_SUPPORT
3c2362e6 278 def_bool y
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SR
279
280config STACKTRACE_SUPPORT
3c2362e6 281 def_bool y
8d5fffb9 282
8d5fffb9 283config MMU
3c2362e6 284 def_bool y
8d5fffb9 285
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DC
286config ARCH_MMAP_RND_BITS_MIN
287 default 28 if 64BIT
288 default 8
289
290config ARCH_MMAP_RND_BITS_MAX
291 default 32 if 64BIT
292 default 16
293
294config ARCH_MMAP_RND_COMPAT_BITS_MIN
295 default 8
296
297config ARCH_MMAP_RND_COMPAT_BITS_MAX
298 default 16
299
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SR
300config SBUS
301 bool
302
303config GENERIC_ISA_DMA
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JB
304 def_bool y
305 depends on ISA_DMA_API
8d5fffb9 306
8d5fffb9 307config GENERIC_BUG
3c2362e6 308 def_bool y
8d5fffb9 309 depends on BUG
b93a531e
JB
310 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
311
312config GENERIC_BUG_RELATIVE_POINTERS
313 bool
8d5fffb9 314
8d5fffb9 315config ARCH_MAY_HAVE_PC_FDC
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JB
316 def_bool y
317 depends on ISA_DMA_API
8d5fffb9 318
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SR
319config GENERIC_CALIBRATE_DELAY
320 def_bool y
321
9a0b8415 322config ARCH_HAS_CPU_RELAX
323 def_bool y
324
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DH
325config ARCH_HAS_FILTER_PGPROT
326 def_bool y
327
dd5af90a 328config HAVE_SETUP_PER_CPU_AREA
89c9c4c5 329 def_bool y
b32ef636 330
08fc4580
TH
331config NEED_PER_CPU_EMBED_FIRST_CHUNK
332 def_bool y
333
334config NEED_PER_CPU_PAGE_FIRST_CHUNK
11124411
TH
335 def_bool y
336
801e4062
JB
337config ARCH_HIBERNATION_POSSIBLE
338 def_bool y
801e4062 339
f4cb5700
JB
340config ARCH_SUSPEND_POSSIBLE
341 def_bool y
f4cb5700 342
53313b2c
SC
343config ARCH_WANT_GENERAL_HUGETLB
344 def_bool y
345
8d5fffb9 346config ZONE_DMA32
e0fd24a3 347 def_bool y if X86_64
8d5fffb9 348
8d5fffb9 349config AUDIT_ARCH
e0fd24a3 350 def_bool y if X86_64
8d5fffb9 351
d6f2d75a
AR
352config KASAN_SHADOW_OFFSET
353 hex
354 depends on KASAN
355 default 0xdffffc0000000000
356
69575d38
SW
357config HAVE_INTEL_TXT
358 def_bool y
6ea30386 359 depends on INTEL_IOMMU && ACPI
69575d38 360
6b0c3d44
SR
361config X86_32_SMP
362 def_bool y
363 depends on X86_32 && SMP
364
365config X86_64_SMP
366 def_bool y
367 depends on X86_64 && SMP
368
2b144498
SD
369config ARCH_SUPPORTS_UPROBES
370 def_bool y
371
d20642f0
RH
372config FIX_EARLYCON_MEM
373 def_bool y
374
94d49eb3
KS
375config DYNAMIC_PHYSICAL_MASK
376 bool
377
98233368
KS
378config PGTABLE_LEVELS
379 int
77ef56e4 380 default 5 if X86_5LEVEL
98233368
KS
381 default 4 if X86_64
382 default 3 if X86_PAE
383 default 2
384
2a61f474
MY
385config CC_HAS_SANE_STACKPROTECTOR
386 bool
387 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
388 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
389 help
390 We have to make sure stack protector is unconditionally disabled if
3fb0fdb3
AL
391 the compiler produces broken code or if it does not let us control
392 the segment on 32-bit kernels.
2a61f474 393
506f1d07
SR
394menu "Processor type and features"
395
5ee71535
RD
396config ZONE_DMA
397 bool "DMA memory allocation support" if EXPERT
398 default y
399 help
400 DMA memory allocation support allows devices with less than 32-bit
401 addressing to allocate within the first 16MB of address space.
402 Disable if no such devices will be used.
403
404 If unsure, say Y.
405
506f1d07
SR
406config SMP
407 bool "Symmetric multi-processing support"
a7f7f624 408 help
506f1d07 409 This enables support for systems with more than one CPU. If you have
4a474157
RG
410 a system with only one CPU, say N. If you have a system with more
411 than one CPU, say Y.
506f1d07 412
4a474157 413 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
414 machines, but will use only one CPU of a multiprocessor machine. If
415 you say Y here, the kernel will run on many, but not all,
4a474157 416 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
417 will run faster if you say N here.
418
419 Note that if you say Y here and choose architecture "586" or
420 "Pentium" under "Processor family", the kernel will not work on 486
421 architectures. Similarly, multiprocessor kernels for the "PPro"
422 architecture may not work on all Pentium based boards.
423
424 People using multiprocessor machines who say Y here should also say
425 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
426 Management" code will be disabled if you say Y here.
427
cb1aaebe 428 See also <file:Documentation/x86/i386/IO-APIC.rst>,
4f4cfa6c 429 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
430 <http://www.tldp.org/docs.html#howto>.
431
432 If you don't know what to do here, say N.
433
9def39be
JT
434config X86_FEATURE_NAMES
435 bool "Processor feature human-readable names" if EMBEDDED
436 default y
a7f7f624 437 help
9def39be
JT
438 This option compiles in a table of x86 feature bits and corresponding
439 names. This is required to support /proc/cpuinfo and a few kernel
440 messages. You can disable this to save space, at the expense of
441 making those few kernel messages show numeric feature bits instead.
442
443 If in doubt, say Y.
444
06cd9a7d
YL
445config X86_X2APIC
446 bool "Support x2apic"
19e3d60d 447 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 448 help
06cd9a7d
YL
449 This enables x2apic support on CPUs that have this feature.
450
451 This allows 32-bit apic IDs (so it can support very large systems),
452 and accesses the local apic via MSRs not via mmio.
453
06cd9a7d
YL
454 If you don't know what to do here, say N.
455
6695c85b 456config X86_MPPARSE
4590d98f 457 bool "Enable MPS table" if ACPI
7a527688 458 default y
5ab74722 459 depends on X86_LOCAL_APIC
a7f7f624 460 help
6695c85b
YL
461 For old smp systems that do not have proper acpi support. Newer systems
462 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 463
ddd70cf9 464config GOLDFISH
b03b016f
KK
465 def_bool y
466 depends on X86_GOLDFISH
ddd70cf9 467
76b04384
DW
468config RETPOLINE
469 bool "Avoid speculative indirect branches in kernel"
470 default y
471 help
472 Compile kernel with the retpoline compiler options to guard against
473 kernel-to-user data leaks by avoiding speculative indirect
474 branches. Requires a compiler with -mindirect-branch=thunk-extern
475 support for full protection. The kernel may run slower.
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.
8425091f 524endif
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.
543endif
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
ddd70cf9
JN
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.
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
1ea7c673 619 select APB_TIMER
54b34aa0 620 select INTEL_SCU_PCI
15a713df 621 select MFD_INTEL_MSIC
a7f7f624 622 help
4cb9b00f
DC
623 Select to build a kernel capable of supporting Intel MID (Mobile
624 Internet Device) platform systems which do not have the PCI legacy
625 interfaces. If you are building for a PC class system say N here.
1ea7c673 626
4cb9b00f
DC
627 Intel MID platforms are based on an Intel processor and chipset which
628 consume less power than most of the x86 derivatives.
43605ef1 629
8bbc2a13
BD
630config X86_INTEL_QUARK
631 bool "Intel Quark platform support"
632 depends on X86_32
633 depends on X86_EXTENDED_PLATFORM
634 depends on X86_PLATFORM_DEVICES
635 depends on X86_TSC
636 depends on PCI
637 depends on PCI_GOANY
638 depends on X86_IO_APIC
639 select IOSF_MBI
640 select INTEL_IMR
9ab6eb51 641 select COMMON_CLK
a7f7f624 642 help
8bbc2a13
BD
643 Select to include support for Quark X1000 SoC.
644 Say Y here if you have a Quark based system such as the Arduino
645 compatible Intel Galileo.
646
3d48aab1
MW
647config X86_INTEL_LPSS
648 bool "Intel Low Power Subsystem Support"
5962dd22 649 depends on X86 && ACPI && PCI
3d48aab1 650 select COMMON_CLK
0f531431 651 select PINCTRL
eebb3e8d 652 select IOSF_MBI
a7f7f624 653 help
3d48aab1
MW
654 Select to build support for Intel Low Power Subsystem such as
655 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
656 things like clock tree (common clock framework) and pincontrol
657 which are needed by the LPSS peripheral drivers.
3d48aab1 658
92082a88
KX
659config X86_AMD_PLATFORM_DEVICE
660 bool "AMD ACPI2Platform devices support"
661 depends on ACPI
662 select COMMON_CLK
663 select PINCTRL
a7f7f624 664 help
92082a88
KX
665 Select to interpret AMD specific ACPI device to platform device
666 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
667 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
668 implemented under PINCTRL subsystem.
669
ced3ce76
DB
670config IOSF_MBI
671 tristate "Intel SoC IOSF Sideband support for SoC platforms"
672 depends on PCI
a7f7f624 673 help
ced3ce76
DB
674 This option enables sideband register access support for Intel SoC
675 platforms. On these platforms the IOSF sideband is used in lieu of
676 MSR's for some register accesses, mostly but not limited to thermal
677 and power. Drivers may query the availability of this device to
678 determine if they need the sideband in order to work on these
679 platforms. The sideband is available on the following SoC products.
680 This list is not meant to be exclusive.
681 - BayTrail
682 - Braswell
683 - Quark
684
685 You should say Y if you are running a kernel on one of these SoC's.
686
ed2226bd
DB
687config IOSF_MBI_DEBUG
688 bool "Enable IOSF sideband access through debugfs"
689 depends on IOSF_MBI && DEBUG_FS
a7f7f624 690 help
ed2226bd
DB
691 Select this option to expose the IOSF sideband access registers (MCR,
692 MDR, MCRX) through debugfs to write and read register information from
693 different units on the SoC. This is most useful for obtaining device
694 state information for debug and analysis. As this is a general access
695 mechanism, users of this option would have specific knowledge of the
696 device they want to access.
697
698 If you don't require the option or are in doubt, say N.
699
c5c606d9
RT
700config X86_RDC321X
701 bool "RDC R-321x SoC"
506f1d07 702 depends on X86_32
c5c606d9
RT
703 depends on X86_EXTENDED_PLATFORM
704 select M486
705 select X86_REBOOTFIXUPS
a7f7f624 706 help
c5c606d9
RT
707 This option is needed for RDC R-321x system-on-chip, also known
708 as R-8610-(G).
709 If you don't have one of these chips, you should say N here.
710
e0c7ae37 711config X86_32_NON_STANDARD
9c398017
IM
712 bool "Support non-standard 32-bit SMP architectures"
713 depends on X86_32 && SMP
c5c606d9 714 depends on X86_EXTENDED_PLATFORM
a7f7f624 715 help
b5660ba7
PA
716 This option compiles in the bigsmp and STA2X11 default
717 subarchitectures. It is intended for a generic binary
718 kernel. If you select them all, kernel will probe it one by
719 one and will fallback to default.
d49c4288 720
c5c606d9 721# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 722
d949f36f 723config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 724 def_bool y
d949f36f
LT
725 # MCE code calls memory_failure():
726 depends on X86_MCE
727 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
728 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
729 depends on X86_64 || !SPARSEMEM
730 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 731
83125a3a
AR
732config STA2X11
733 bool "STA2X11 Companion Chip Support"
734 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
735 select SWIOTLB
736 select MFD_STA2X11
0145071b 737 select GPIOLIB
a7f7f624 738 help
83125a3a
AR
739 This adds support for boards based on the STA2X11 IO-Hub,
740 a.k.a. "ConneXt". The chip is used in place of the standard
741 PC chipset, so all "standard" peripherals are missing. If this
742 option is selected the kernel will still be able to boot on
743 standard PC machines.
744
82148d1d
S
745config X86_32_IRIS
746 tristate "Eurobraille/Iris poweroff module"
747 depends on X86_32
a7f7f624 748 help
82148d1d
S
749 The Iris machines from EuroBraille do not have APM or ACPI support
750 to shut themselves down properly. A special I/O sequence is
751 needed to do so, which is what this module does at
752 kernel shutdown.
753
754 This is only for Iris machines from EuroBraille.
755
756 If unused, say N.
757
ae1e9130 758config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
759 def_bool y
760 prompt "Single-depth WCHAN output"
a87d0914 761 depends on X86
a7f7f624 762 help
506f1d07
SR
763 Calculate simpler /proc/<PID>/wchan values. If this option
764 is disabled then wchan values will recurse back to the
765 caller function. This provides more accurate wchan values,
766 at the expense of slightly more scheduling overhead.
767
768 If in doubt, say "Y".
769
6276a074
BP
770menuconfig HYPERVISOR_GUEST
771 bool "Linux guest support"
a7f7f624 772 help
6276a074
BP
773 Say Y here to enable options for running Linux under various hyper-
774 visors. This option enables basic hypervisor detection and platform
775 setup.
506f1d07 776
6276a074
BP
777 If you say N, all options in this submenu will be skipped and
778 disabled, and Linux guest support won't be built in.
506f1d07 779
6276a074 780if HYPERVISOR_GUEST
506f1d07 781
e61bd94a
EPH
782config PARAVIRT
783 bool "Enable paravirtualization code"
a0e2bf7c 784 depends on HAVE_STATIC_CALL
a7f7f624 785 help
e61bd94a
EPH
786 This changes the kernel so it can modify itself when it is run
787 under a hypervisor, potentially improving performance significantly
788 over full virtualization. However, when run without a hypervisor
789 the kernel is theoretically slower and slightly larger.
790
c00a280a
JG
791config PARAVIRT_XXL
792 bool
793
6276a074
BP
794config PARAVIRT_DEBUG
795 bool "paravirt-ops debugging"
796 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 797 help
6276a074
BP
798 Enable to debug paravirt_ops internals. Specifically, BUG if
799 a paravirt_op is missing when it is called.
800
b4ecc126
JF
801config PARAVIRT_SPINLOCKS
802 bool "Paravirtualization layer for spinlocks"
6ea30386 803 depends on PARAVIRT && SMP
a7f7f624 804 help
b4ecc126
JF
805 Paravirtualized spinlocks allow a pvops backend to replace the
806 spinlock implementation with something virtualization-friendly
807 (for example, block the virtual CPU rather than spinning).
808
4c4e4f61
R
809 It has a minimal impact on native kernels and gives a nice performance
810 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 811
4c4e4f61 812 If you are unsure how to answer this question, answer Y.
b4ecc126 813
ecca2502
ZY
814config X86_HV_CALLBACK_VECTOR
815 def_bool n
816
6276a074 817source "arch/x86/xen/Kconfig"
7af192c9 818
6276a074
BP
819config KVM_GUEST
820 bool "KVM Guest support (including kvmclock)"
821 depends on PARAVIRT
822 select PARAVIRT_CLOCK
a1c4423b 823 select ARCH_CPUIDLE_HALTPOLL
b1d40575 824 select X86_HV_CALLBACK_VECTOR
6276a074 825 default y
a7f7f624 826 help
6276a074
BP
827 This option enables various optimizations for running under the KVM
828 hypervisor. It includes a paravirtualized clock, so that instead
829 of relying on a PIT (or probably other) emulation by the
830 underlying device model, the host provides the guest with
831 timing infrastructure such as time of day, and system time
506f1d07 832
a1c4423b 833config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
834 def_bool n
835 prompt "Disable host haltpoll when loading haltpoll driver"
836 help
a1c4423b
MT
837 If virtualized under KVM, disable host haltpoll.
838
7733607f
MW
839config PVH
840 bool "Support for running PVH guests"
a7f7f624 841 help
7733607f
MW
842 This option enables the PVH entry point for guest virtual machines
843 as specified in the x86/HVM direct boot ABI.
844
6276a074
BP
845config PARAVIRT_TIME_ACCOUNTING
846 bool "Paravirtual steal time accounting"
847 depends on PARAVIRT
a7f7f624 848 help
6276a074
BP
849 Select this option to enable fine granularity task steal time
850 accounting. Time spent executing other tasks in parallel with
851 the current vCPU is discounted from the vCPU power. To account for
852 that, there can be a small performance impact.
853
854 If in doubt, say N here.
855
856config PARAVIRT_CLOCK
857 bool
97349135 858
4a362601
JK
859config JAILHOUSE_GUEST
860 bool "Jailhouse non-root cell support"
abde587b 861 depends on X86_64 && PCI
87e65d05 862 select X86_PM_TIMER
a7f7f624 863 help
4a362601
JK
864 This option allows to run Linux as guest in a Jailhouse non-root
865 cell. You can leave this option disabled if you only want to start
866 Jailhouse and run Linux afterwards in the root cell.
867
ec7972c9
ZY
868config ACRN_GUEST
869 bool "ACRN Guest support"
870 depends on X86_64
498ad393 871 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
872 help
873 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
874 a flexible, lightweight reference open-source hypervisor, built with
875 real-time and safety-criticality in mind. It is built for embedded
876 IOT with small footprint and real-time features. More details can be
877 found in https://projectacrn.org/.
878
6276a074 879endif #HYPERVISOR_GUEST
97349135 880
506f1d07
SR
881source "arch/x86/Kconfig.cpu"
882
883config HPET_TIMER
3c2362e6 884 def_bool X86_64
506f1d07 885 prompt "HPET Timer Support" if X86_32
a7f7f624 886 help
8f9ca475
IM
887 Use the IA-PC HPET (High Precision Event Timer) to manage
888 time in preference to the PIT and RTC, if a HPET is
889 present.
890 HPET is the next generation timer replacing legacy 8254s.
891 The HPET provides a stable time base on SMP
892 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
893 as it is off-chip. The interface used is documented
894 in the HPET spec, revision 1.
506f1d07 895
8f9ca475
IM
896 You can safely choose Y here. However, HPET will only be
897 activated if the platform and the BIOS support this feature.
898 Otherwise the 8254 will be used for timing services.
506f1d07 899
8f9ca475 900 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
901
902config HPET_EMULATE_RTC
3c2362e6 903 def_bool y
3228e1dc 904 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 905
6a108a14 906# Mark as expert because too many people got it wrong.
506f1d07 907# The code disables itself when not needed.
7ae9392c
TP
908config DMI
909 default y
cf074402 910 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 911 bool "Enable DMI scanning" if EXPERT
a7f7f624 912 help
7ae9392c
TP
913 Enabled scanning of DMI to identify machine quirks. Say Y
914 here unless you have verified that your setup is not
915 affected by entries in the DMI blacklist. Required by PNP
916 BIOS code.
917
506f1d07 918config GART_IOMMU
38901f1c 919 bool "Old AMD GART IOMMU support"
2f9237d4 920 select DMA_OPS
a4ce5a48 921 select IOMMU_HELPER
506f1d07 922 select SWIOTLB
23ac4ae8 923 depends on X86_64 && PCI && AMD_NB
a7f7f624 924 help
ced3c42c
IM
925 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
926 GART based hardware IOMMUs.
927
928 The GART supports full DMA access for devices with 32-bit access
929 limitations, on systems with more than 3 GB. This is usually needed
930 for USB, sound, many IDE/SATA chipsets and some other devices.
931
932 Newer systems typically have a modern AMD IOMMU, supported via
933 the CONFIG_AMD_IOMMU=y config option.
934
935 In normal configurations this driver is only active when needed:
936 there's more than 3 GB of memory and the system contains a
937 32-bit limited device.
938
939 If unsure, say Y.
506f1d07 940
1184dc2f 941config MAXSMP
ddb0c5a6 942 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 943 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 944 select CPUMASK_OFFSTACK
a7f7f624 945 help
ddb0c5a6 946 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 947 If unsure, say N.
506f1d07 948
aec6487e
IM
949#
950# The maximum number of CPUs supported:
951#
952# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
953# and which can be configured interactively in the
954# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
955#
956# The ranges are different on 32-bit and 64-bit kernels, depending on
957# hardware capabilities and scalability features of the kernel.
958#
959# ( If MAXSMP is enabled we just use the highest possible value and disable
960# interactive configuration. )
961#
962
963config NR_CPUS_RANGE_BEGIN
a0d0bb4d 964 int
aec6487e
IM
965 default NR_CPUS_RANGE_END if MAXSMP
966 default 1 if !SMP
967 default 2
a0d0bb4d 968
aec6487e 969config NR_CPUS_RANGE_END
a0d0bb4d 970 int
aec6487e
IM
971 depends on X86_32
972 default 64 if SMP && X86_BIGSMP
973 default 8 if SMP && !X86_BIGSMP
974 default 1 if !SMP
a0d0bb4d 975
aec6487e 976config NR_CPUS_RANGE_END
a0d0bb4d 977 int
aec6487e 978 depends on X86_64
1edae1ae
SW
979 default 8192 if SMP && CPUMASK_OFFSTACK
980 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 981 default 1 if !SMP
a0d0bb4d 982
aec6487e 983config NR_CPUS_DEFAULT
a0d0bb4d
RD
984 int
985 depends on X86_32
aec6487e
IM
986 default 32 if X86_BIGSMP
987 default 8 if SMP
988 default 1 if !SMP
a0d0bb4d 989
aec6487e 990config NR_CPUS_DEFAULT
a0d0bb4d
RD
991 int
992 depends on X86_64
aec6487e
IM
993 default 8192 if MAXSMP
994 default 64 if SMP
995 default 1 if !SMP
a0d0bb4d 996
506f1d07 997config NR_CPUS
36f5101a 998 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
999 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1000 default NR_CPUS_DEFAULT
a7f7f624 1001 help
506f1d07 1002 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1003 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1004 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1005 minimum value which makes sense is 2.
1006
aec6487e
IM
1007 This is purely to save memory: each supported CPU adds about 8KB
1008 to the kernel image.
506f1d07
SR
1009
1010config SCHED_SMT
dbe73364 1011 def_bool y if SMP
506f1d07
SR
1012
1013config SCHED_MC
3c2362e6
HH
1014 def_bool y
1015 prompt "Multi-core scheduler support"
c8e56d20 1016 depends on SMP
a7f7f624 1017 help
506f1d07
SR
1018 Multi-core scheduler support improves the CPU scheduler's decision
1019 making when dealing with multi-core CPU chips at a cost of slightly
1020 increased overhead in some places. If unsure say N here.
1021
de966cf4
TC
1022config SCHED_MC_PRIO
1023 bool "CPU core priorities scheduler support"
0a21fc12
IM
1024 depends on SCHED_MC && CPU_SUP_INTEL
1025 select X86_INTEL_PSTATE
1026 select CPU_FREQ
de966cf4 1027 default y
a7f7f624 1028 help
0a21fc12
IM
1029 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1030 core ordering determined at manufacturing time, which allows
1031 certain cores to reach higher turbo frequencies (when running
1032 single threaded workloads) than others.
de966cf4 1033
0a21fc12
IM
1034 Enabling this kernel feature teaches the scheduler about
1035 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1036 scheduler's CPU selection logic accordingly, so that higher
1037 overall system performance can be achieved.
de966cf4 1038
0a21fc12 1039 This feature will have no effect on CPUs without this feature.
de966cf4 1040
0a21fc12 1041 If unsure say Y here.
5e76b2ab 1042
30b8b006 1043config UP_LATE_INIT
b03b016f
KK
1044 def_bool y
1045 depends on !SMP && X86_LOCAL_APIC
30b8b006 1046
506f1d07 1047config X86_UP_APIC
50849eef
JB
1048 bool "Local APIC support on uniprocessors" if !PCI_MSI
1049 default PCI_MSI
38a1dfda 1050 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1051 help
506f1d07
SR
1052 A local APIC (Advanced Programmable Interrupt Controller) is an
1053 integrated interrupt controller in the CPU. If you have a single-CPU
1054 system which has a processor with a local APIC, you can say Y here to
1055 enable and use it. If you say Y here even though your machine doesn't
1056 have a local APIC, then the kernel will still run with no slowdown at
1057 all. The local APIC supports CPU-generated self-interrupts (timer,
1058 performance counters), and the NMI watchdog which detects hard
1059 lockups.
1060
1061config X86_UP_IOAPIC
1062 bool "IO-APIC support on uniprocessors"
1063 depends on X86_UP_APIC
a7f7f624 1064 help
506f1d07
SR
1065 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1066 SMP-capable replacement for PC-style interrupt controllers. Most
1067 SMP systems and many recent uniprocessor systems have one.
1068
1069 If you have a single-CPU system with an IO-APIC, you can say Y here
1070 to use it. If you say Y here even though your machine doesn't have
1071 an IO-APIC, then the kernel will still run with no slowdown at all.
1072
1073config X86_LOCAL_APIC
3c2362e6 1074 def_bool y
0dbc6078 1075 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1076 select IRQ_DOMAIN_HIERARCHY
52f518a3 1077 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
506f1d07
SR
1078
1079config X86_IO_APIC
b1da1e71
JB
1080 def_bool y
1081 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1082
41b9eb26
SA
1083config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1084 bool "Reroute for broken boot IRQs"
41b9eb26 1085 depends on X86_IO_APIC
a7f7f624 1086 help
41b9eb26
SA
1087 This option enables a workaround that fixes a source of
1088 spurious interrupts. This is recommended when threaded
1089 interrupt handling is used on systems where the generation of
1090 superfluous "boot interrupts" cannot be disabled.
1091
1092 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1093 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1094 kernel does during interrupt handling). On chipsets where this
1095 boot IRQ generation cannot be disabled, this workaround keeps
1096 the original IRQ line masked so that only the equivalent "boot
1097 IRQ" is delivered to the CPUs. The workaround also tells the
1098 kernel to set up the IRQ handler on the boot IRQ line. In this
1099 way only one interrupt is delivered to the kernel. Otherwise
1100 the spurious second interrupt may cause the kernel to bring
1101 down (vital) interrupt lines.
1102
1103 Only affects "broken" chipsets. Interrupt sharing may be
1104 increased on these systems.
1105
506f1d07 1106config X86_MCE
bab9bc65 1107 bool "Machine Check / overheating reporting"
648ed940 1108 select GENERIC_ALLOCATOR
e57dbaf7 1109 default y
a7f7f624 1110 help
bab9bc65
AK
1111 Machine Check support allows the processor to notify the
1112 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1113 The action the kernel takes depends on the severity of the problem,
bab9bc65 1114 ranging from warning messages to halting the machine.
4efc0670 1115
5de97c9f
TL
1116config X86_MCELOG_LEGACY
1117 bool "Support for deprecated /dev/mcelog character device"
1118 depends on X86_MCE
a7f7f624 1119 help
5de97c9f
TL
1120 Enable support for /dev/mcelog which is needed by the old mcelog
1121 userspace logging daemon. Consider switching to the new generation
1122 rasdaemon solution.
1123
506f1d07 1124config X86_MCE_INTEL
3c2362e6
HH
1125 def_bool y
1126 prompt "Intel MCE features"
c1ebf835 1127 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1128 help
506f1d07
SR
1129 Additional support for intel specific MCE features such as
1130 the thermal monitor.
1131
1132config X86_MCE_AMD
3c2362e6
HH
1133 def_bool y
1134 prompt "AMD MCE features"
f5382de9 1135 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
a7f7f624 1136 help
506f1d07
SR
1137 Additional support for AMD specific MCE features such as
1138 the DRAM Error Threshold.
1139
4efc0670 1140config X86_ANCIENT_MCE
6fc108a0 1141 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1142 depends on X86_32 && X86_MCE
a7f7f624 1143 help
cd13adcc 1144 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1145 systems. These typically need to be enabled explicitly on the command
cd13adcc 1146 line.
4efc0670 1147
b2762686
AK
1148config X86_MCE_THRESHOLD
1149 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1150 def_bool y
b2762686 1151
ea149b36 1152config X86_MCE_INJECT
bc8e80d5 1153 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1154 tristate "Machine check injector support"
a7f7f624 1155 help
ea149b36
AK
1156 Provide support for injecting machine checks for testing purposes.
1157 If you don't know what a machine check is and you don't do kernel
1158 QA it is safe to say n.
1159
07dc900e 1160source "arch/x86/events/Kconfig"
e633c65a 1161
5aef51c3 1162config X86_LEGACY_VM86
1e642812 1163 bool "Legacy VM86 support"
506f1d07 1164 depends on X86_32
a7f7f624 1165 help
5aef51c3
AL
1166 This option allows user programs to put the CPU into V8086
1167 mode, which is an 80286-era approximation of 16-bit real mode.
1168
1169 Some very old versions of X and/or vbetool require this option
1170 for user mode setting. Similarly, DOSEMU will use it if
1171 available to accelerate real mode DOS programs. However, any
1172 recent version of DOSEMU, X, or vbetool should be fully
1173 functional even without kernel VM86 support, as they will all
1e642812
IM
1174 fall back to software emulation. Nevertheless, if you are using
1175 a 16-bit DOS program where 16-bit performance matters, vm86
1176 mode might be faster than emulation and you might want to
1177 enable this option.
5aef51c3 1178
1e642812
IM
1179 Note that any app that works on a 64-bit kernel is unlikely to
1180 need this option, as 64-bit kernels don't, and can't, support
1181 V8086 mode. This option is also unrelated to 16-bit protected
1182 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1183
1e642812
IM
1184 Enabling this option increases the complexity of the kernel
1185 and slows down exception handling a tiny bit.
5aef51c3 1186
1e642812 1187 If unsure, say N here.
5aef51c3
AL
1188
1189config VM86
b03b016f
KK
1190 bool
1191 default X86_LEGACY_VM86
34273f41
PA
1192
1193config X86_16BIT
1194 bool "Enable support for 16-bit segments" if EXPERT
1195 default y
a5b9e5a2 1196 depends on MODIFY_LDT_SYSCALL
a7f7f624 1197 help
34273f41
PA
1198 This option is required by programs like Wine to run 16-bit
1199 protected mode legacy code on x86 processors. Disabling
1200 this option saves about 300 bytes on i386, or around 6K text
1201 plus 16K runtime memory on x86-64,
1202
1203config X86_ESPFIX32
1204 def_bool y
1205 depends on X86_16BIT && X86_32
506f1d07 1206
197725de
PA
1207config X86_ESPFIX64
1208 def_bool y
34273f41 1209 depends on X86_16BIT && X86_64
506f1d07 1210
1ad83c85 1211config X86_VSYSCALL_EMULATION
b03b016f
KK
1212 bool "Enable vsyscall emulation" if EXPERT
1213 default y
1214 depends on X86_64
a7f7f624 1215 help
1ad83c85
AL
1216 This enables emulation of the legacy vsyscall page. Disabling
1217 it is roughly equivalent to booting with vsyscall=none, except
1218 that it will also disable the helpful warning if a program
1219 tries to use a vsyscall. With this option set to N, offending
1220 programs will just segfault, citing addresses of the form
1221 0xffffffffff600?00.
1222
1223 This option is required by many programs built before 2013, and
1224 care should be used even with newer programs if set to N.
1225
1226 Disabling this option saves about 7K of kernel size and
1227 possibly 4K of additional runtime pagetable memory.
1228
111e7b15
TG
1229config X86_IOPL_IOPERM
1230 bool "IOPERM and IOPL Emulation"
a24ca997 1231 default y
a7f7f624 1232 help
111e7b15
TG
1233 This enables the ioperm() and iopl() syscalls which are necessary
1234 for legacy applications.
1235
c8137ace
TG
1236 Legacy IOPL support is an overbroad mechanism which allows user
1237 space aside of accessing all 65536 I/O ports also to disable
1238 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1239 capabilities and permission from potentially active security
1240 modules.
1241
1242 The emulation restricts the functionality of the syscall to
1243 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1244 ability to disable interrupts from user space which would be
1245 granted if the hardware IOPL mechanism would be used.
c8137ace 1246
506f1d07
SR
1247config TOSHIBA
1248 tristate "Toshiba Laptop support"
1249 depends on X86_32
a7f7f624 1250 help
506f1d07
SR
1251 This adds a driver to safely access the System Management Mode of
1252 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1253 not work on models with a Phoenix BIOS. The System Management Mode
1254 is used to set the BIOS and power saving options on Toshiba portables.
1255
1256 For information on utilities to make use of this driver see the
1257 Toshiba Linux utilities web site at:
1258 <http://www.buzzard.org.uk/toshiba/>.
1259
1260 Say Y if you intend to run this kernel on a Toshiba portable.
1261 Say N otherwise.
1262
1263config I8K
039ae585 1264 tristate "Dell i8k legacy laptop support"
949a9d70 1265 select HWMON
039ae585 1266 select SENSORS_DELL_SMM
a7f7f624 1267 help
039ae585
PR
1268 This option enables legacy /proc/i8k userspace interface in hwmon
1269 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1270 temperature and allows controlling fan speeds of Dell laptops via
1271 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1272 it reports also power and hotkey status. For fan speed control is
1273 needed userspace package i8kutils.
1274
1275 Say Y if you intend to run this kernel on old Dell laptops or want to
1276 use userspace package i8kutils.
506f1d07
SR
1277 Say N otherwise.
1278
1279config X86_REBOOTFIXUPS
9ba16087
JB
1280 bool "Enable X86 board specific fixups for reboot"
1281 depends on X86_32
a7f7f624 1282 help
506f1d07
SR
1283 This enables chipset and/or board specific fixups to be done
1284 in order to get reboot to work correctly. This is only needed on
1285 some combinations of hardware and BIOS. The symptom, for which
1286 this config is intended, is when reboot ends with a stalled/hung
1287 system.
1288
1289 Currently, the only fixup is for the Geode machines using
5e3a77e9 1290 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1291
1292 Say Y if you want to enable the fixup. Currently, it's safe to
1293 enable this option even if you don't need it.
1294 Say N otherwise.
1295
1296config MICROCODE
9a2bc335
BP
1297 bool "CPU microcode loading support"
1298 default y
80030e3d 1299 depends on CPU_SUP_AMD || CPU_SUP_INTEL
a7f7f624 1300 help
506f1d07 1301 If you say Y here, you will be able to update the microcode on
5f9c01aa
BP
1302 Intel and AMD processors. The Intel support is for the IA32 family,
1303 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1304 AMD support is for families 0x10 and later. You will obviously need
1305 the actual microcode binary data itself which is not shipped with
1306 the Linux kernel.
1307
1308 The preferred method to load microcode from a detached initrd is described
cb1aaebe 1309 in Documentation/x86/microcode.rst. For that you need to enable
5f9c01aa
BP
1310 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1311 initrd for microcode blobs.
1312
c508c46e
BG
1313 In addition, you can build the microcode into the kernel. For that you
1314 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1315 config option.
506f1d07 1316
8d86f390 1317config MICROCODE_INTEL
e43f6e67 1318 bool "Intel microcode loading support"
8f9ca475
IM
1319 depends on MICROCODE
1320 default MICROCODE
a7f7f624 1321 help
8f9ca475
IM
1322 This options enables microcode patch loading support for Intel
1323 processors.
1324
b8989db9
A
1325 For the current Intel microcode data package go to
1326 <https://downloadcenter.intel.com> and search for
1327 'Linux Processor Microcode Data File'.
8d86f390 1328
80cc9f10 1329config MICROCODE_AMD
e43f6e67 1330 bool "AMD microcode loading support"
8f9ca475 1331 depends on MICROCODE
a7f7f624 1332 help
8f9ca475
IM
1333 If you select this option, microcode patch loading support for AMD
1334 processors will be enabled.
80cc9f10 1335
8f9ca475 1336config MICROCODE_OLD_INTERFACE
c02f48e0
BP
1337 bool "Ancient loading interface (DEPRECATED)"
1338 default n
506f1d07 1339 depends on MICROCODE
a7f7f624 1340 help
c02f48e0
BP
1341 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1342 which was used by userspace tools like iucode_tool and microcode.ctl.
1343 It is inadequate because it runs too late to be able to properly
1344 load microcode on a machine and it needs special tools. Instead, you
1345 should've switched to the early loading method with the initrd or
cb1aaebe 1346 builtin microcode by now: Documentation/x86/microcode.rst
506f1d07
SR
1347
1348config X86_MSR
1349 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1350 help
506f1d07
SR
1351 This device gives privileged processes access to the x86
1352 Model-Specific Registers (MSRs). It is a character device with
1353 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1354 MSR accesses are directed to a specific CPU on multi-processor
1355 systems.
1356
1357config X86_CPUID
1358 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1359 help
506f1d07
SR
1360 This device gives processes access to the x86 CPUID instruction to
1361 be executed on a specific processor. It is a character device
1362 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1363 /dev/cpu/31/cpuid.
1364
1365choice
1366 prompt "High Memory Support"
6fc108a0 1367 default HIGHMEM4G
506f1d07
SR
1368 depends on X86_32
1369
1370config NOHIGHMEM
1371 bool "off"
a7f7f624 1372 help
506f1d07
SR
1373 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1374 However, the address space of 32-bit x86 processors is only 4
1375 Gigabytes large. That means that, if you have a large amount of
1376 physical memory, not all of it can be "permanently mapped" by the
1377 kernel. The physical memory that's not permanently mapped is called
1378 "high memory".
1379
1380 If you are compiling a kernel which will never run on a machine with
1381 more than 1 Gigabyte total physical RAM, answer "off" here (default
1382 choice and suitable for most users). This will result in a "3GB/1GB"
1383 split: 3GB are mapped so that each process sees a 3GB virtual memory
1384 space and the remaining part of the 4GB virtual memory space is used
1385 by the kernel to permanently map as much physical memory as
1386 possible.
1387
1388 If the machine has between 1 and 4 Gigabytes physical RAM, then
1389 answer "4GB" here.
1390
1391 If more than 4 Gigabytes is used then answer "64GB" here. This
1392 selection turns Intel PAE (Physical Address Extension) mode on.
1393 PAE implements 3-level paging on IA32 processors. PAE is fully
1394 supported by Linux, PAE mode is implemented on all recent Intel
1395 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1396 then the kernel will not boot on CPUs that don't support PAE!
1397
1398 The actual amount of total physical memory will either be
1399 auto detected or can be forced by using a kernel command line option
1400 such as "mem=256M". (Try "man bootparam" or see the documentation of
1401 your boot loader (lilo or loadlin) about how to pass options to the
1402 kernel at boot time.)
1403
1404 If unsure, say "off".
1405
1406config HIGHMEM4G
1407 bool "4GB"
a7f7f624 1408 help
506f1d07
SR
1409 Select this if you have a 32-bit processor and between 1 and 4
1410 gigabytes of physical RAM.
1411
1412config HIGHMEM64G
1413 bool "64GB"
0ef3439c 1414 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
506f1d07 1415 select X86_PAE
a7f7f624 1416 help
506f1d07
SR
1417 Select this if you have a 32-bit processor and more than 4
1418 gigabytes of physical RAM.
1419
1420endchoice
1421
1422choice
6a108a14 1423 prompt "Memory split" if EXPERT
506f1d07
SR
1424 default VMSPLIT_3G
1425 depends on X86_32
a7f7f624 1426 help
506f1d07
SR
1427 Select the desired split between kernel and user memory.
1428
1429 If the address range available to the kernel is less than the
1430 physical memory installed, the remaining memory will be available
1431 as "high memory". Accessing high memory is a little more costly
1432 than low memory, as it needs to be mapped into the kernel first.
1433 Note that increasing the kernel address space limits the range
1434 available to user programs, making the address space there
1435 tighter. Selecting anything other than the default 3G/1G split
1436 will also likely make your kernel incompatible with binary-only
1437 kernel modules.
1438
1439 If you are not absolutely sure what you are doing, leave this
1440 option alone!
1441
1442 config VMSPLIT_3G
1443 bool "3G/1G user/kernel split"
1444 config VMSPLIT_3G_OPT
1445 depends on !X86_PAE
1446 bool "3G/1G user/kernel split (for full 1G low memory)"
1447 config VMSPLIT_2G
1448 bool "2G/2G user/kernel split"
1449 config VMSPLIT_2G_OPT
1450 depends on !X86_PAE
1451 bool "2G/2G user/kernel split (for full 2G low memory)"
1452 config VMSPLIT_1G
1453 bool "1G/3G user/kernel split"
1454endchoice
1455
1456config PAGE_OFFSET
1457 hex
1458 default 0xB0000000 if VMSPLIT_3G_OPT
1459 default 0x80000000 if VMSPLIT_2G
1460 default 0x78000000 if VMSPLIT_2G_OPT
1461 default 0x40000000 if VMSPLIT_1G
1462 default 0xC0000000
1463 depends on X86_32
1464
1465config HIGHMEM
3c2362e6 1466 def_bool y
506f1d07 1467 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1468
1469config X86_PAE
9ba16087 1470 bool "PAE (Physical Address Extension) Support"
506f1d07 1471 depends on X86_32 && !HIGHMEM4G
d4a451d5 1472 select PHYS_ADDR_T_64BIT
9d99c712 1473 select SWIOTLB
a7f7f624 1474 help
506f1d07
SR
1475 PAE is required for NX support, and furthermore enables
1476 larger swapspace support for non-overcommit purposes. It
1477 has the cost of more pagetable lookup overhead, and also
1478 consumes more pagetable space per process.
1479
77ef56e4
KS
1480config X86_5LEVEL
1481 bool "Enable 5-level page tables support"
18ec1eaf 1482 default y
eedb92ab 1483 select DYNAMIC_MEMORY_LAYOUT
162434e7 1484 select SPARSEMEM_VMEMMAP
77ef56e4 1485 depends on X86_64
a7f7f624 1486 help
77ef56e4
KS
1487 5-level paging enables access to larger address space:
1488 upto 128 PiB of virtual address space and 4 PiB of
1489 physical address space.
1490
1491 It will be supported by future Intel CPUs.
1492
6657fca0
KS
1493 A kernel with the option enabled can be booted on machines that
1494 support 4- or 5-level paging.
77ef56e4 1495
cb1aaebe 1496 See Documentation/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1497 information.
1498
1499 Say N if unsure.
1500
10971ab2 1501config X86_DIRECT_GBPAGES
e5008abe 1502 def_bool y
2e1da13f 1503 depends on X86_64
a7f7f624 1504 help
10971ab2
IM
1505 Certain kernel features effectively disable kernel
1506 linear 1 GB mappings (even if the CPU otherwise
1507 supports them), so don't confuse the user by printing
1508 that we have them enabled.
9e899816 1509
5c280cf6
TG
1510config X86_CPA_STATISTICS
1511 bool "Enable statistic for Change Page Attribute"
1512 depends on DEBUG_FS
a7f7f624 1513 help
b75baaf3 1514 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1515 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1516 page mappings when mapping protections are changed.
1517
7744ccdb
TL
1518config AMD_MEM_ENCRYPT
1519 bool "AMD Secure Memory Encryption (SME) support"
1520 depends on X86_64 && CPU_SUP_AMD
82fef0ad 1521 select DMA_COHERENT_POOL
94d49eb3 1522 select DYNAMIC_PHYSICAL_MASK
ce9084ba 1523 select ARCH_USE_MEMREMAP_PROT
9087c375 1524 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
597cfe48 1525 select INSTRUCTION_DECODER
22916417 1526 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
a7f7f624 1527 help
7744ccdb
TL
1528 Say yes to enable support for the encryption of system memory.
1529 This requires an AMD processor that supports Secure Memory
1530 Encryption (SME).
1531
1532config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1533 bool "Activate AMD Secure Memory Encryption (SME) by default"
1534 default y
1535 depends on AMD_MEM_ENCRYPT
a7f7f624 1536 help
7744ccdb
TL
1537 Say yes to have system memory encrypted by default if running on
1538 an AMD processor that supports Secure Memory Encryption (SME).
1539
1540 If set to Y, then the encryption of system memory can be
1541 deactivated with the mem_encrypt=off command line option.
1542
1543 If set to N, then the encryption of system memory can be
1544 activated with the mem_encrypt=on command line option.
1545
506f1d07
SR
1546# Common NUMA Features
1547config NUMA
e133f6ea 1548 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1549 depends on SMP
b5660ba7
PA
1550 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1551 default y if X86_BIGSMP
a7f7f624 1552 help
e133f6ea 1553 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1554
506f1d07
SR
1555 The kernel will try to allocate memory used by a CPU on the
1556 local memory controller of the CPU and add some more
1557 NUMA awareness to the kernel.
1558
c280ea5e 1559 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1560 (or later), AMD Opteron, or EM64T NUMA.
1561
b5660ba7 1562 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1563 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1564
1565 Otherwise, you should say N.
506f1d07 1566
eec1d4fa 1567config AMD_NUMA
3c2362e6
HH
1568 def_bool y
1569 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1570 depends on X86_64 && NUMA && PCI
a7f7f624 1571 help
eec1d4fa
HR
1572 Enable AMD NUMA node topology detection. You should say Y here if
1573 you have a multi processor AMD system. This uses an old method to
1574 read the NUMA configuration directly from the builtin Northbridge
1575 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1576 which also takes priority if both are compiled in.
506f1d07
SR
1577
1578config X86_64_ACPI_NUMA
3c2362e6
HH
1579 def_bool y
1580 prompt "ACPI NUMA detection"
506f1d07
SR
1581 depends on X86_64 && NUMA && ACPI && PCI
1582 select ACPI_NUMA
a7f7f624 1583 help
506f1d07
SR
1584 Enable ACPI SRAT based node topology detection.
1585
1586config NUMA_EMU
1587 bool "NUMA emulation"
1b7e03ef 1588 depends on NUMA
a7f7f624 1589 help
506f1d07
SR
1590 Enable NUMA emulation. A flat machine will be split
1591 into virtual nodes when booted with "numa=fake=N", where N is the
1592 number of nodes. This is only useful for debugging.
1593
1594config NODES_SHIFT
d25e26b6 1595 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1596 range 1 10
1597 default "10" if MAXSMP
506f1d07 1598 default "6" if X86_64
506f1d07
SR
1599 default "3"
1600 depends on NEED_MULTIPLE_NODES
a7f7f624 1601 help
1184dc2f 1602 Specify the maximum number of NUMA Nodes available on the target
692105b8 1603 system. Increases memory reserved to accommodate various tables.
506f1d07 1604
506f1d07
SR
1605config ARCH_FLATMEM_ENABLE
1606 def_bool y
3b16651f 1607 depends on X86_32 && !NUMA
506f1d07 1608
506f1d07
SR
1609config ARCH_SPARSEMEM_ENABLE
1610 def_bool y
6ea30386 1611 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1612 select SPARSEMEM_STATIC if X86_32
1613 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1614
3b16651f 1615config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1616 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1617
506f1d07
SR
1618config ARCH_SELECT_MEMORY_MODEL
1619 def_bool y
b263295d 1620 depends on ARCH_SPARSEMEM_ENABLE
506f1d07
SR
1621
1622config ARCH_MEMORY_PROBE
a0842b70 1623 bool "Enable sysfs memory/probe interface"
3120e25e 1624 depends on X86_64 && MEMORY_HOTPLUG
a0842b70
TK
1625 help
1626 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1627 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1628 If you are unsure how to answer this question, answer N.
506f1d07 1629
3b16651f
TH
1630config ARCH_PROC_KCORE_TEXT
1631 def_bool y
1632 depends on X86_64 && PROC_KCORE
1633
a29815a3 1634config ILLEGAL_POINTER_VALUE
b03b016f
KK
1635 hex
1636 default 0 if X86_32
1637 default 0xdead000000000000 if X86_64
a29815a3 1638
7a67832c
DW
1639config X86_PMEM_LEGACY_DEVICE
1640 bool
1641
ec776ef6 1642config X86_PMEM_LEGACY
7a67832c 1643 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1644 depends on PHYS_ADDR_T_64BIT
1645 depends on BLK_DEV
7a67832c 1646 select X86_PMEM_LEGACY_DEVICE
7b27a862 1647 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1648 select LIBNVDIMM
ec776ef6
CH
1649 help
1650 Treat memory marked using the non-standard e820 type of 12 as used
1651 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1652 The kernel will offer these regions to the 'pmem' driver so
1653 they can be used for persistent storage.
1654
1655 Say Y if unsure.
1656
506f1d07
SR
1657config HIGHPTE
1658 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1659 depends on HIGHMEM
a7f7f624 1660 help
506f1d07
SR
1661 The VM uses one page table entry for each page of physical memory.
1662 For systems with a lot of RAM, this can be wasteful of precious
1663 low memory. Setting this option will put user-space page table
1664 entries in high memory.
1665
9f077871 1666config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1667 bool "Check for low memory corruption"
a7f7f624 1668 help
8f9ca475
IM
1669 Periodically check for memory corruption in low memory, which
1670 is suspected to be caused by BIOS. Even when enabled in the
1671 configuration, it is disabled at runtime. Enable it by
1672 setting "memory_corruption_check=1" on the kernel command
1673 line. By default it scans the low 64k of memory every 60
1674 seconds; see the memory_corruption_check_size and
1675 memory_corruption_check_period parameters in
8c27ceff 1676 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1677
1678 When enabled with the default parameters, this option has
1679 almost no overhead, as it reserves a relatively small amount
1680 of memory and scans it infrequently. It both detects corruption
1681 and prevents it from affecting the running system.
1682
1683 It is, however, intended as a diagnostic tool; if repeatable
1684 BIOS-originated corruption always affects the same memory,
1685 you can use memmap= to prevent the kernel from using that
1686 memory.
9f077871 1687
c885df50 1688config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1689 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1690 depends on X86_CHECK_BIOS_CORRUPTION
1691 default y
a7f7f624 1692 help
8f9ca475
IM
1693 Set whether the default state of memory_corruption_check is
1694 on or off.
c885df50 1695
9ea77bdb 1696config X86_RESERVE_LOW
d0cd7425
PA
1697 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1698 default 64
1699 range 4 640
a7f7f624 1700 help
d0cd7425
PA
1701 Specify the amount of low memory to reserve for the BIOS.
1702
1703 The first page contains BIOS data structures that the kernel
1704 must not use, so that page must always be reserved.
1705
1706 By default we reserve the first 64K of physical RAM, as a
1707 number of BIOSes are known to corrupt that memory range
1708 during events such as suspend/resume or monitor cable
1709 insertion, so it must not be used by the kernel.
fc381519 1710
d0cd7425
PA
1711 You can set this to 4 if you are absolutely sure that you
1712 trust the BIOS to get all its memory reservations and usages
1713 right. If you know your BIOS have problems beyond the
1714 default 64K area, you can set this to 640 to avoid using the
1715 entire low memory range.
fc381519 1716
d0cd7425
PA
1717 If you have doubts about the BIOS (e.g. suspend/resume does
1718 not work or there's kernel crashes after certain hardware
1719 hotplug events) then you might want to enable
1720 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1721 typical corruption patterns.
fc381519 1722
d0cd7425 1723 Leave this to the default value of 64 if you are unsure.
fc381519 1724
506f1d07
SR
1725config MATH_EMULATION
1726 bool
a5b9e5a2 1727 depends on MODIFY_LDT_SYSCALL
87d6021b 1728 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1729 help
506f1d07
SR
1730 Linux can emulate a math coprocessor (used for floating point
1731 operations) if you don't have one. 486DX and Pentium processors have
1732 a math coprocessor built in, 486SX and 386 do not, unless you added
1733 a 487DX or 387, respectively. (The messages during boot time can
1734 give you some hints here ["man dmesg"].) Everyone needs either a
1735 coprocessor or this emulation.
1736
1737 If you don't have a math coprocessor, you need to say Y here; if you
1738 say Y here even though you have a coprocessor, the coprocessor will
1739 be used nevertheless. (This behavior can be changed with the kernel
1740 command line option "no387", which comes handy if your coprocessor
1741 is broken. Try "man bootparam" or see the documentation of your boot
1742 loader (lilo or loadlin) about how to pass options to the kernel at
1743 boot time.) This means that it is a good idea to say Y here if you
1744 intend to use this kernel on different machines.
1745
1746 More information about the internals of the Linux math coprocessor
1747 emulation can be found in <file:arch/x86/math-emu/README>.
1748
1749 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1750 kernel, it won't hurt.
1751
1752config MTRR
6fc108a0 1753 def_bool y
6a108a14 1754 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1755 help
506f1d07
SR
1756 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1757 the Memory Type Range Registers (MTRRs) may be used to control
1758 processor access to memory ranges. This is most useful if you have
1759 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1760 allows bus write transfers to be combined into a larger transfer
1761 before bursting over the PCI/AGP bus. This can increase performance
1762 of image write operations 2.5 times or more. Saying Y here creates a
1763 /proc/mtrr file which may be used to manipulate your processor's
1764 MTRRs. Typically the X server should use this.
1765
1766 This code has a reasonably generic interface so that similar
1767 control registers on other processors can be easily supported
1768 as well:
1769
1770 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1771 Registers (ARRs) which provide a similar functionality to MTRRs. For
1772 these, the ARRs are used to emulate the MTRRs.
1773 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1774 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1775 write-combining. All of these processors are supported by this code
1776 and it makes sense to say Y here if you have one of them.
1777
1778 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1779 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1780 can lead to all sorts of problems, so it's good to say Y here.
1781
1782 You can safely say Y even if your machine doesn't have MTRRs, you'll
1783 just add about 9 KB to your kernel.
1784
cb1aaebe 1785 See <file:Documentation/x86/mtrr.rst> for more information.
506f1d07 1786
95ffa243 1787config MTRR_SANITIZER
2ffb3501 1788 def_bool y
95ffa243
YL
1789 prompt "MTRR cleanup support"
1790 depends on MTRR
a7f7f624 1791 help
aba3728c
TG
1792 Convert MTRR layout from continuous to discrete, so X drivers can
1793 add writeback entries.
95ffa243 1794
aba3728c 1795 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1796 The largest mtrr entry size for a continuous block can be set with
aba3728c 1797 mtrr_chunk_size.
95ffa243 1798
2ffb3501 1799 If unsure, say Y.
95ffa243
YL
1800
1801config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1802 int "MTRR cleanup enable value (0-1)"
1803 range 0 1
1804 default "0"
95ffa243 1805 depends on MTRR_SANITIZER
a7f7f624 1806 help
f5098d62 1807 Enable mtrr cleanup default value
95ffa243 1808
12031a62
YL
1809config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1810 int "MTRR cleanup spare reg num (0-7)"
1811 range 0 7
1812 default "1"
1813 depends on MTRR_SANITIZER
a7f7f624 1814 help
12031a62 1815 mtrr cleanup spare entries default, it can be changed via
aba3728c 1816 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1817
2e5d9c85 1818config X86_PAT
6fc108a0 1819 def_bool y
6a108a14 1820 prompt "x86 PAT support" if EXPERT
2a8a2719 1821 depends on MTRR
a7f7f624 1822 help
2e5d9c85 1823 Use PAT attributes to setup page level cache control.
042b78e4 1824
2e5d9c85 1825 PATs are the modern equivalents of MTRRs and are much more
1826 flexible than MTRRs.
1827
1828 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1829 spontaneous reboots) or a non-working video driver.
2e5d9c85 1830
1831 If unsure, say Y.
1832
46cf98cd
VP
1833config ARCH_USES_PG_UNCACHED
1834 def_bool y
1835 depends on X86_PAT
1836
628c6246
PA
1837config ARCH_RANDOM
1838 def_bool y
1839 prompt "x86 architectural random number generator" if EXPERT
a7f7f624 1840 help
628c6246
PA
1841 Enable the x86 architectural RDRAND instruction
1842 (Intel Bull Mountain technology) to generate random numbers.
1843 If supported, this is a high bandwidth, cryptographically
1844 secure hardware random number generator.
1845
51ae4a2d
PA
1846config X86_SMAP
1847 def_bool y
1848 prompt "Supervisor Mode Access Prevention" if EXPERT
a7f7f624 1849 help
51ae4a2d
PA
1850 Supervisor Mode Access Prevention (SMAP) is a security
1851 feature in newer Intel processors. There is a small
1852 performance cost if this enabled and turned on; there is
1853 also a small increase in the kernel size if this is enabled.
1854
1855 If unsure, say Y.
1856
b971880f 1857config X86_UMIP
796ebc81 1858 def_bool y
b971880f 1859 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1860 help
b971880f
BM
1861 User Mode Instruction Prevention (UMIP) is a security feature in
1862 some x86 processors. If enabled, a general protection fault is
1863 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1864 executed in user mode. These instructions unnecessarily expose
1865 information about the hardware state.
796ebc81
RN
1866
1867 The vast majority of applications do not use these instructions.
1868 For the very few that do, software emulation is provided in
1869 specific cases in protected and virtual-8086 modes. Emulated
1870 results are dummy.
aa35f896 1871
35e97790 1872config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1873 prompt "Memory Protection Keys"
35e97790 1874 def_bool y
284244a9 1875 # Note: only available in 64-bit mode
38f3e775 1876 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1877 select ARCH_USES_HIGH_VMA_FLAGS
1878 select ARCH_HAS_PKEYS
a7f7f624 1879 help
284244a9
DH
1880 Memory Protection Keys provides a mechanism for enforcing
1881 page-based protections, but without requiring modification of the
1882 page tables when an application changes protection domains.
1883
1eecbcdc 1884 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1885
1886 If unsure, say y.
35e97790 1887
db616173
MH
1888choice
1889 prompt "TSX enable mode"
1890 depends on CPU_SUP_INTEL
1891 default X86_INTEL_TSX_MODE_OFF
1892 help
1893 Intel's TSX (Transactional Synchronization Extensions) feature
1894 allows to optimize locking protocols through lock elision which
1895 can lead to a noticeable performance boost.
1896
1897 On the other hand it has been shown that TSX can be exploited
1898 to form side channel attacks (e.g. TAA) and chances are there
1899 will be more of those attacks discovered in the future.
1900
1901 Therefore TSX is not enabled by default (aka tsx=off). An admin
1902 might override this decision by tsx=on the command line parameter.
1903 Even with TSX enabled, the kernel will attempt to enable the best
1904 possible TAA mitigation setting depending on the microcode available
1905 for the particular machine.
1906
1907 This option allows to set the default tsx mode between tsx=on, =off
1908 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1909 details.
1910
1911 Say off if not sure, auto if TSX is in use but it should be used on safe
1912 platforms or on if TSX is in use and the security aspect of tsx is not
1913 relevant.
1914
1915config X86_INTEL_TSX_MODE_OFF
1916 bool "off"
1917 help
1918 TSX is disabled if possible - equals to tsx=off command line parameter.
1919
1920config X86_INTEL_TSX_MODE_ON
1921 bool "on"
1922 help
1923 TSX is always enabled on TSX capable HW - equals the tsx=on command
1924 line parameter.
1925
1926config X86_INTEL_TSX_MODE_AUTO
1927 bool "auto"
1928 help
1929 TSX is enabled on TSX capable HW that is believed to be safe against
1930 side channel attacks- equals the tsx=auto command line parameter.
1931endchoice
1932
e7e05452
SC
1933config X86_SGX
1934 bool "Software Guard eXtensions (SGX)"
1935 depends on X86_64 && CPU_SUP_INTEL
1936 depends on CRYPTO=y
1937 depends on CRYPTO_SHA256=y
1938 select SRCU
1939 select MMU_NOTIFIER
901ddbb9 1940 select NUMA_KEEP_MEMINFO if NUMA
e7e05452
SC
1941 help
1942 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1943 that can be used by applications to set aside private regions of code
1944 and data, referred to as enclaves. An enclave's private memory can
1945 only be accessed by code running within the enclave. Accesses from
1946 outside the enclave, including other enclaves, are disallowed by
1947 hardware.
1948
1949 If unsure, say N.
1950
506f1d07 1951config EFI
9ba16087 1952 bool "EFI runtime service support"
5b83683f 1953 depends on ACPI
f6ce5002 1954 select UCS2_STRING
022ee6c5 1955 select EFI_RUNTIME_WRAPPERS
a7f7f624 1956 help
8f9ca475
IM
1957 This enables the kernel to use EFI runtime services that are
1958 available (such as the EFI variable services).
506f1d07 1959
8f9ca475
IM
1960 This option is only useful on systems that have EFI firmware.
1961 In addition, you should use the latest ELILO loader available
1962 at <http://elilo.sourceforge.net> in order to take advantage
1963 of EFI runtime services. However, even with this option, the
1964 resultant kernel should continue to boot on existing non-EFI
1965 platforms.
506f1d07 1966
291f3632 1967config EFI_STUB
8f24f8c2
AB
1968 bool "EFI stub support"
1969 depends on EFI && !X86_USE_3DNOW
1970 depends on $(cc-option,-mabi=ms) || X86_32
1971 select RELOCATABLE
a7f7f624 1972 help
8f24f8c2 1973 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
1974 by EFI firmware without the use of a bootloader.
1975
4f4cfa6c 1976 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1977
7d453eee
MF
1978config EFI_MIXED
1979 bool "EFI mixed-mode support"
1980 depends on EFI_STUB && X86_64
a7f7f624 1981 help
7d453eee
MF
1982 Enabling this feature allows a 64-bit kernel to be booted
1983 on a 32-bit firmware, provided that your CPU supports 64-bit
1984 mode.
1985
1986 Note that it is not possible to boot a mixed-mode enabled
1987 kernel via the EFI boot stub - a bootloader that supports
1988 the EFI handover protocol must be used.
1989
1990 If unsure, say N.
1991
8636a1f9 1992source "kernel/Kconfig.hz"
506f1d07
SR
1993
1994config KEXEC
1995 bool "kexec system call"
2965faa5 1996 select KEXEC_CORE
a7f7f624 1997 help
506f1d07
SR
1998 kexec is a system call that implements the ability to shutdown your
1999 current kernel, and to start another kernel. It is like a reboot
2000 but it is independent of the system firmware. And like a reboot
2001 you can start any kernel with it, not just Linux.
2002
2003 The name comes from the similarity to the exec system call.
2004
2005 It is an ongoing process to be certain the hardware in a machine
2006 is properly shutdown, so do not be surprised if this code does not
bf220695
GU
2007 initially work for you. As of this writing the exact hardware
2008 interface is strongly in flux, so no good recommendation can be
2009 made.
506f1d07 2010
74ca317c
VG
2011config KEXEC_FILE
2012 bool "kexec file based system call"
2965faa5 2013 select KEXEC_CORE
74ca317c 2014 select BUILD_BIN2C
74ca317c
VG
2015 depends on X86_64
2016 depends on CRYPTO=y
2017 depends on CRYPTO_SHA256=y
a7f7f624 2018 help
74ca317c
VG
2019 This is new version of kexec system call. This system call is
2020 file based and takes file descriptors as system call argument
2021 for kernel and initramfs as opposed to list of segments as
2022 accepted by previous system call.
2023
b799a09f
AT
2024config ARCH_HAS_KEXEC_PURGATORY
2025 def_bool KEXEC_FILE
2026
99d5cadf 2027config KEXEC_SIG
8e7d8381 2028 bool "Verify kernel signature during kexec_file_load() syscall"
74ca317c 2029 depends on KEXEC_FILE
a7f7f624 2030 help
d8eb8940 2031
99d5cadf
JB
2032 This option makes the kexec_file_load() syscall check for a valid
2033 signature of the kernel image. The image can still be loaded without
2034 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2035 there's a signature that we can check, then it must be valid.
2036
2037 In addition to this option, you need to enable signature
d8eb8940
BP
2038 verification for the corresponding kernel image type being
2039 loaded in order for this to work.
8e7d8381 2040
99d5cadf
JB
2041config KEXEC_SIG_FORCE
2042 bool "Require a valid signature in kexec_file_load() syscall"
2043 depends on KEXEC_SIG
a7f7f624 2044 help
99d5cadf
JB
2045 This option makes kernel signature verification mandatory for
2046 the kexec_file_load() syscall.
2047
8e7d8381
VG
2048config KEXEC_BZIMAGE_VERIFY_SIG
2049 bool "Enable bzImage signature verification support"
99d5cadf 2050 depends on KEXEC_SIG
8e7d8381
VG
2051 depends on SIGNED_PE_FILE_VERIFICATION
2052 select SYSTEM_TRUSTED_KEYRING
a7f7f624 2053 help
8e7d8381
VG
2054 Enable bzImage signature verification support.
2055
506f1d07 2056config CRASH_DUMP
04b69447 2057 bool "kernel crash dumps"
506f1d07 2058 depends on X86_64 || (X86_32 && HIGHMEM)
a7f7f624 2059 help
506f1d07
SR
2060 Generate crash dump after being started by kexec.
2061 This should be normally only set in special crash dump kernels
2062 which are loaded in the main kernel with kexec-tools into
2063 a specially reserved region and then later executed after
2064 a crash by kdump/kexec. The crash dump kernel must be compiled
2065 to a memory address not used by the main kernel or BIOS using
2066 PHYSICAL_START, or it must be built as a relocatable image
2067 (CONFIG_RELOCATABLE=y).
330d4810 2068 For more details see Documentation/admin-guide/kdump/kdump.rst
506f1d07 2069
3ab83521 2070config KEXEC_JUMP
6ea30386 2071 bool "kexec jump"
fee7b0d8 2072 depends on KEXEC && HIBERNATION
a7f7f624 2073 help
89081d17
HY
2074 Jump between original kernel and kexeced kernel and invoke
2075 code in physical address mode via KEXEC
3ab83521 2076
506f1d07 2077config PHYSICAL_START
6a108a14 2078 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2079 default "0x1000000"
a7f7f624 2080 help
506f1d07
SR
2081 This gives the physical address where the kernel is loaded.
2082
2083 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2084 bzImage will decompress itself to above physical address and
2085 run from there. Otherwise, bzImage will run from the address where
2086 it has been loaded by the boot loader and will ignore above physical
2087 address.
2088
2089 In normal kdump cases one does not have to set/change this option
2090 as now bzImage can be compiled as a completely relocatable image
2091 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2092 address. This option is mainly useful for the folks who don't want
2093 to use a bzImage for capturing the crash dump and want to use a
2094 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2095 to be specifically compiled to run from a specific memory area
2096 (normally a reserved region) and this option comes handy.
2097
ceefccc9
PA
2098 So if you are using bzImage for capturing the crash dump,
2099 leave the value here unchanged to 0x1000000 and set
2100 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2101 for capturing the crash dump change this value to start of
2102 the reserved region. In other words, it can be set based on
2103 the "X" value as specified in the "crashkernel=YM@XM"
2104 command line boot parameter passed to the panic-ed
330d4810 2105 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2106 for more details about crash dumps.
506f1d07
SR
2107
2108 Usage of bzImage for capturing the crash dump is recommended as
2109 one does not have to build two kernels. Same kernel can be used
2110 as production kernel and capture kernel. Above option should have
2111 gone away after relocatable bzImage support is introduced. But it
2112 is present because there are users out there who continue to use
2113 vmlinux for dump capture. This option should go away down the
2114 line.
2115
2116 Don't change this unless you know what you are doing.
2117
2118config RELOCATABLE
26717808
PA
2119 bool "Build a relocatable kernel"
2120 default y
a7f7f624 2121 help
506f1d07
SR
2122 This builds a kernel image that retains relocation information
2123 so it can be loaded someplace besides the default 1MB.
2124 The relocations tend to make the kernel binary about 10% larger,
2125 but are discarded at runtime.
2126
2127 One use is for the kexec on panic case where the recovery kernel
2128 must live at a different physical address than the primary
2129 kernel.
2130
2131 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2132 it has been loaded at and the compile time physical address
8ab3820f 2133 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2134
8ab3820f 2135config RANDOMIZE_BASE
e8581e3d 2136 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2137 depends on RELOCATABLE
6807c846 2138 default y
a7f7f624 2139 help
e8581e3d
BH
2140 In support of Kernel Address Space Layout Randomization (KASLR),
2141 this randomizes the physical address at which the kernel image
2142 is decompressed and the virtual address where the kernel
2143 image is mapped, as a security feature that deters exploit
2144 attempts relying on knowledge of the location of kernel
2145 code internals.
2146
ed9f007e
KC
2147 On 64-bit, the kernel physical and virtual addresses are
2148 randomized separately. The physical address will be anywhere
2149 between 16MB and the top of physical memory (up to 64TB). The
2150 virtual address will be randomized from 16MB up to 1GB (9 bits
2151 of entropy). Note that this also reduces the memory space
2152 available to kernel modules from 1.5GB to 1GB.
2153
2154 On 32-bit, the kernel physical and virtual addresses are
2155 randomized together. They will be randomized from 16MB up to
2156 512MB (8 bits of entropy).
e8581e3d
BH
2157
2158 Entropy is generated using the RDRAND instruction if it is
2159 supported. If RDTSC is supported, its value is mixed into
2160 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2161 supported, then entropy is read from the i8254 timer. The
2162 usable entropy is limited by the kernel being built using
2163 2GB addressing, and that PHYSICAL_ALIGN must be at a
2164 minimum of 2MB. As a result, only 10 bits of entropy are
2165 theoretically possible, but the implementations are further
2166 limited due to memory layouts.
e8581e3d 2167
6807c846 2168 If unsure, say Y.
8ab3820f
KC
2169
2170# Relocation on x86 needs some additional build support
845adf72
PA
2171config X86_NEED_RELOCS
2172 def_bool y
8ab3820f 2173 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2174
506f1d07 2175config PHYSICAL_ALIGN
a0215061 2176 hex "Alignment value to which kernel should be aligned"
8ab3820f 2177 default "0x200000"
a0215061
KC
2178 range 0x2000 0x1000000 if X86_32
2179 range 0x200000 0x1000000 if X86_64
a7f7f624 2180 help
506f1d07
SR
2181 This value puts the alignment restrictions on physical address
2182 where kernel is loaded and run from. Kernel is compiled for an
2183 address which meets above alignment restriction.
2184
2185 If bootloader loads the kernel at a non-aligned address and
2186 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2187 address aligned to above value and run from there.
2188
2189 If bootloader loads the kernel at a non-aligned address and
2190 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2191 load address and decompress itself to the address it has been
2192 compiled for and run from there. The address for which kernel is
2193 compiled already meets above alignment restrictions. Hence the
2194 end result is that kernel runs from a physical address meeting
2195 above alignment restrictions.
2196
a0215061
KC
2197 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2198 this value must be a multiple of 0x200000.
2199
506f1d07
SR
2200 Don't change this unless you know what you are doing.
2201
eedb92ab
KS
2202config DYNAMIC_MEMORY_LAYOUT
2203 bool
a7f7f624 2204 help
eedb92ab
KS
2205 This option makes base addresses of vmalloc and vmemmap as well as
2206 __PAGE_OFFSET movable during boot.
2207
0483e1fa
TG
2208config RANDOMIZE_MEMORY
2209 bool "Randomize the kernel memory sections"
2210 depends on X86_64
2211 depends on RANDOMIZE_BASE
eedb92ab 2212 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2213 default RANDOMIZE_BASE
a7f7f624 2214 help
0483e1fa
TG
2215 Randomizes the base virtual address of kernel memory sections
2216 (physical memory mapping, vmalloc & vmemmap). This security feature
2217 makes exploits relying on predictable memory locations less reliable.
2218
2219 The order of allocations remains unchanged. Entropy is generated in
2220 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2221 configuration have in average 30,000 different possible virtual
2222 addresses for each memory section.
2223
6807c846 2224 If unsure, say Y.
0483e1fa 2225
90397a41
TG
2226config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2227 hex "Physical memory mapping padding" if EXPERT
2228 depends on RANDOMIZE_MEMORY
2229 default "0xa" if MEMORY_HOTPLUG
2230 default "0x0"
2231 range 0x1 0x40 if MEMORY_HOTPLUG
2232 range 0x0 0x40
a7f7f624 2233 help
90397a41
TG
2234 Define the padding in terabytes added to the existing physical
2235 memory size during kernel memory randomization. It is useful
2236 for memory hotplug support but reduces the entropy available for
2237 address randomization.
2238
2239 If unsure, leave at the default value.
2240
506f1d07 2241config HOTPLUG_CPU
bebd024e 2242 def_bool y
40b31360 2243 depends on SMP
506f1d07 2244
80aa1dff
FY
2245config BOOTPARAM_HOTPLUG_CPU0
2246 bool "Set default setting of cpu0_hotpluggable"
2c922cd0 2247 depends on HOTPLUG_CPU
a7f7f624 2248 help
80aa1dff
FY
2249 Set whether default state of cpu0_hotpluggable is on or off.
2250
2251 Say Y here to enable CPU0 hotplug by default. If this switch
2252 is turned on, there is no need to give cpu0_hotplug kernel
2253 parameter and the CPU0 hotplug feature is enabled by default.
2254
2255 Please note: there are two known CPU0 dependencies if you want
2256 to enable the CPU0 hotplug feature either by this switch or by
2257 cpu0_hotplug kernel parameter.
2258
2259 First, resume from hibernate or suspend always starts from CPU0.
2260 So hibernate and suspend are prevented if CPU0 is offline.
2261
2262 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2263 offline if any interrupt can not migrate out of CPU0. There may
2264 be other CPU0 dependencies.
2265
2266 Please make sure the dependencies are under your control before
2267 you enable this feature.
2268
2269 Say N if you don't want to enable CPU0 hotplug feature by default.
2270 You still can enable the CPU0 hotplug feature at boot by kernel
2271 parameter cpu0_hotplug.
2272
a71c8bc5
FY
2273config DEBUG_HOTPLUG_CPU0
2274 def_bool n
2275 prompt "Debug CPU0 hotplug"
2c922cd0 2276 depends on HOTPLUG_CPU
a7f7f624 2277 help
a71c8bc5
FY
2278 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2279 soon as possible and boots up userspace with CPU0 offlined. User
2280 can online CPU0 back after boot time.
2281
2282 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2283 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2284 compilation or giving cpu0_hotplug kernel parameter at boot.
2285
2286 If unsure, say N.
2287
506f1d07 2288config COMPAT_VDSO
b0b49f26
AL
2289 def_bool n
2290 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2291 depends on COMPAT_32
a7f7f624 2292 help
b0b49f26
AL
2293 Certain buggy versions of glibc will crash if they are
2294 presented with a 32-bit vDSO that is not mapped at the address
2295 indicated in its segment table.
e84446de 2296
b0b49f26
AL
2297 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2298 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2299 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2300 the only released version with the bug, but OpenSUSE 9
2301 contains a buggy "glibc 2.3.2".
506f1d07 2302
b0b49f26
AL
2303 The symptom of the bug is that everything crashes on startup, saying:
2304 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2305
2306 Saying Y here changes the default value of the vdso32 boot
2307 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2308 This works around the glibc bug but hurts performance.
2309
2310 If unsure, say N: if you are compiling your own kernel, you
2311 are unlikely to be using a buggy version of glibc.
506f1d07 2312
3dc33bd3
KC
2313choice
2314 prompt "vsyscall table for legacy applications"
2315 depends on X86_64
625b7b7f 2316 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2317 help
2318 Legacy user code that does not know how to find the vDSO expects
2319 to be able to issue three syscalls by calling fixed addresses in
2320 kernel space. Since this location is not randomized with ASLR,
2321 it can be used to assist security vulnerability exploitation.
2322
2323 This setting can be changed at boot time via the kernel command
bd49e16e 2324 line parameter vsyscall=[emulate|xonly|none].
3dc33bd3
KC
2325
2326 On a system with recent enough glibc (2.14 or newer) and no
2327 static binaries, you can say None without a performance penalty
2328 to improve security.
2329
bd49e16e 2330 If unsure, select "Emulate execution only".
3dc33bd3 2331
3dc33bd3 2332 config LEGACY_VSYSCALL_EMULATE
bd49e16e 2333 bool "Full emulation"
3dc33bd3 2334 help
bd49e16e
AL
2335 The kernel traps and emulates calls into the fixed vsyscall
2336 address mapping. This makes the mapping non-executable, but
2337 it still contains readable known contents, which could be
2338 used in certain rare security vulnerability exploits. This
2339 configuration is recommended when using legacy userspace
2340 that still uses vsyscalls along with legacy binary
2341 instrumentation tools that require code to be readable.
2342
2343 An example of this type of legacy userspace is running
2344 Pin on an old binary that still uses vsyscalls.
2345
2346 config LEGACY_VSYSCALL_XONLY
2347 bool "Emulate execution only"
2348 help
2349 The kernel traps and emulates calls into the fixed vsyscall
2350 address mapping and does not allow reads. This
2351 configuration is recommended when userspace might use the
2352 legacy vsyscall area but support for legacy binary
2353 instrumentation of legacy code is not needed. It mitigates
2354 certain uses of the vsyscall area as an ASLR-bypassing
2355 buffer.
3dc33bd3
KC
2356
2357 config LEGACY_VSYSCALL_NONE
2358 bool "None"
2359 help
2360 There will be no vsyscall mapping at all. This will
2361 eliminate any risk of ASLR bypass due to the vsyscall
2362 fixed address mapping. Attempts to use the vsyscalls
2363 will be reported to dmesg, so that either old or
2364 malicious userspace programs can be identified.
2365
2366endchoice
2367
516cbf37
TB
2368config CMDLINE_BOOL
2369 bool "Built-in kernel command line"
a7f7f624 2370 help
516cbf37
TB
2371 Allow for specifying boot arguments to the kernel at
2372 build time. On some systems (e.g. embedded ones), it is
2373 necessary or convenient to provide some or all of the
2374 kernel boot arguments with the kernel itself (that is,
2375 to not rely on the boot loader to provide them.)
2376
2377 To compile command line arguments into the kernel,
2378 set this option to 'Y', then fill in the
69711ca1 2379 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2380
2381 Systems with fully functional boot loaders (i.e. non-embedded)
2382 should leave this option set to 'N'.
2383
2384config CMDLINE
2385 string "Built-in kernel command string"
2386 depends on CMDLINE_BOOL
2387 default ""
a7f7f624 2388 help
516cbf37
TB
2389 Enter arguments here that should be compiled into the kernel
2390 image and used at boot time. If the boot loader provides a
2391 command line at boot time, it is appended to this string to
2392 form the full kernel command line, when the system boots.
2393
2394 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2395 change this behavior.
2396
2397 In most cases, the command line (whether built-in or provided
2398 by the boot loader) should specify the device for the root
2399 file system.
2400
2401config CMDLINE_OVERRIDE
2402 bool "Built-in command line overrides boot loader arguments"
645e6466 2403 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2404 help
516cbf37
TB
2405 Set this option to 'Y' to have the kernel ignore the boot loader
2406 command line, and use ONLY the built-in command line.
2407
2408 This is used to work around broken boot loaders. This should
2409 be set to 'N' under normal conditions.
2410
a5b9e5a2
AL
2411config MODIFY_LDT_SYSCALL
2412 bool "Enable the LDT (local descriptor table)" if EXPERT
2413 default y
a7f7f624 2414 help
a5b9e5a2
AL
2415 Linux can allow user programs to install a per-process x86
2416 Local Descriptor Table (LDT) using the modify_ldt(2) system
2417 call. This is required to run 16-bit or segmented code such as
2418 DOSEMU or some Wine programs. It is also used by some very old
2419 threading libraries.
2420
2421 Enabling this feature adds a small amount of overhead to
2422 context switches and increases the low-level kernel attack
2423 surface. Disabling it removes the modify_ldt(2) system call.
2424
2425 Saying 'N' here may make sense for embedded or server kernels.
2426
b700e7f0
SJ
2427source "kernel/livepatch/Kconfig"
2428
506f1d07
SR
2429endmenu
2430
3072e413
MH
2431config ARCH_HAS_ADD_PAGES
2432 def_bool y
2433 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2434
f91ef222
OS
2435config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2436 def_bool y
2437
e534c7c5 2438config USE_PERCPU_NUMA_NODE_ID
645a7919 2439 def_bool y
e534c7c5
LS
2440 depends on NUMA
2441
da85f865 2442menu "Power management and ACPI options"
e279b6c1
SR
2443
2444config ARCH_HIBERNATION_HEADER
3c2362e6 2445 def_bool y
44556530 2446 depends on HIBERNATION
e279b6c1
SR
2447
2448source "kernel/power/Kconfig"
2449
2450source "drivers/acpi/Kconfig"
2451
a6b68076 2452config X86_APM_BOOT
6fc108a0 2453 def_bool y
282e5aab 2454 depends on APM
a6b68076 2455
e279b6c1
SR
2456menuconfig APM
2457 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2458 depends on X86_32 && PM_SLEEP
a7f7f624 2459 help
e279b6c1
SR
2460 APM is a BIOS specification for saving power using several different
2461 techniques. This is mostly useful for battery powered laptops with
2462 APM compliant BIOSes. If you say Y here, the system time will be
2463 reset after a RESUME operation, the /proc/apm device will provide
2464 battery status information, and user-space programs will receive
2465 notification of APM "events" (e.g. battery status change).
2466
2467 If you select "Y" here, you can disable actual use of the APM
2468 BIOS by passing the "apm=off" option to the kernel at boot time.
2469
2470 Note that the APM support is almost completely disabled for
2471 machines with more than one CPU.
2472
2473 In order to use APM, you will need supporting software. For location
151f4e2b 2474 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2475 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2476 <http://www.tldp.org/docs.html#howto>.
2477
2478 This driver does not spin down disk drives (see the hdparm(8)
2479 manpage ("man 8 hdparm") for that), and it doesn't turn off
2480 VESA-compliant "green" monitors.
2481
2482 This driver does not support the TI 4000M TravelMate and the ACER
2483 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2484 desktop machines also don't have compliant BIOSes, and this driver
2485 may cause those machines to panic during the boot phase.
2486
2487 Generally, if you don't have a battery in your machine, there isn't
2488 much point in using this driver and you should say N. If you get
2489 random kernel OOPSes or reboots that don't seem to be related to
2490 anything, try disabling/enabling this option (or disabling/enabling
2491 APM in your BIOS).
2492
2493 Some other things you should try when experiencing seemingly random,
2494 "weird" problems:
2495
2496 1) make sure that you have enough swap space and that it is
2497 enabled.
2498 2) pass the "no-hlt" option to the kernel
2499 3) switch on floating point emulation in the kernel and pass
2500 the "no387" option to the kernel
2501 4) pass the "floppy=nodma" option to the kernel
2502 5) pass the "mem=4M" option to the kernel (thereby disabling
2503 all but the first 4 MB of RAM)
2504 6) make sure that the CPU is not over clocked.
2505 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2506 8) disable the cache from your BIOS settings
2507 9) install a fan for the video card or exchange video RAM
2508 10) install a better fan for the CPU
2509 11) exchange RAM chips
2510 12) exchange the motherboard.
2511
2512 To compile this driver as a module, choose M here: the
2513 module will be called apm.
2514
2515if APM
2516
2517config APM_IGNORE_USER_SUSPEND
2518 bool "Ignore USER SUSPEND"
a7f7f624 2519 help
e279b6c1
SR
2520 This option will ignore USER SUSPEND requests. On machines with a
2521 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2522 series notebooks, it is necessary to say Y because of a BIOS bug.
2523
2524config APM_DO_ENABLE
2525 bool "Enable PM at boot time"
a7f7f624 2526 help
e279b6c1
SR
2527 Enable APM features at boot time. From page 36 of the APM BIOS
2528 specification: "When disabled, the APM BIOS does not automatically
2529 power manage devices, enter the Standby State, enter the Suspend
2530 State, or take power saving steps in response to CPU Idle calls."
2531 This driver will make CPU Idle calls when Linux is idle (unless this
2532 feature is turned off -- see "Do CPU IDLE calls", below). This
2533 should always save battery power, but more complicated APM features
2534 will be dependent on your BIOS implementation. You may need to turn
2535 this option off if your computer hangs at boot time when using APM
2536 support, or if it beeps continuously instead of suspending. Turn
2537 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2538 T400CDT. This is off by default since most machines do fine without
2539 this feature.
2540
2541config APM_CPU_IDLE
dd8af076 2542 depends on CPU_IDLE
e279b6c1 2543 bool "Make CPU Idle calls when idle"
a7f7f624 2544 help
e279b6c1
SR
2545 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2546 On some machines, this can activate improved power savings, such as
2547 a slowed CPU clock rate, when the machine is idle. These idle calls
2548 are made after the idle loop has run for some length of time (e.g.,
2549 333 mS). On some machines, this will cause a hang at boot time or
2550 whenever the CPU becomes idle. (On machines with more than one CPU,
2551 this option does nothing.)
2552
2553config APM_DISPLAY_BLANK
2554 bool "Enable console blanking using APM"
a7f7f624 2555 help
e279b6c1
SR
2556 Enable console blanking using the APM. Some laptops can use this to
2557 turn off the LCD backlight when the screen blanker of the Linux
2558 virtual console blanks the screen. Note that this is only used by
2559 the virtual console screen blanker, and won't turn off the backlight
2560 when using the X Window system. This also doesn't have anything to
2561 do with your VESA-compliant power-saving monitor. Further, this
2562 option doesn't work for all laptops -- it might not turn off your
2563 backlight at all, or it might print a lot of errors to the console,
2564 especially if you are using gpm.
2565
2566config APM_ALLOW_INTS
2567 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2568 help
e279b6c1
SR
2569 Normally we disable external interrupts while we are making calls to
2570 the APM BIOS as a measure to lessen the effects of a badly behaving
2571 BIOS implementation. The BIOS should reenable interrupts if it
2572 needs to. Unfortunately, some BIOSes do not -- especially those in
2573 many of the newer IBM Thinkpads. If you experience hangs when you
2574 suspend, try setting this to Y. Otherwise, say N.
2575
e279b6c1
SR
2576endif # APM
2577
bb0a56ec 2578source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2579
2580source "drivers/cpuidle/Kconfig"
2581
27471fdb
AH
2582source "drivers/idle/Kconfig"
2583
e279b6c1
SR
2584endmenu
2585
2586
2587menu "Bus options (PCI etc.)"
2588
e279b6c1
SR
2589choice
2590 prompt "PCI access mode"
efefa6f6 2591 depends on X86_32 && PCI
e279b6c1 2592 default PCI_GOANY
a7f7f624 2593 help
e279b6c1
SR
2594 On PCI systems, the BIOS can be used to detect the PCI devices and
2595 determine their configuration. However, some old PCI motherboards
2596 have BIOS bugs and may crash if this is done. Also, some embedded
2597 PCI-based systems don't have any BIOS at all. Linux can also try to
2598 detect the PCI hardware directly without using the BIOS.
2599
2600 With this option, you can specify how Linux should detect the
2601 PCI devices. If you choose "BIOS", the BIOS will be used,
2602 if you choose "Direct", the BIOS won't be used, and if you
2603 choose "MMConfig", then PCI Express MMCONFIG will be used.
2604 If you choose "Any", the kernel will try MMCONFIG, then the
2605 direct access method and falls back to the BIOS if that doesn't
2606 work. If unsure, go with the default, which is "Any".
2607
2608config PCI_GOBIOS
2609 bool "BIOS"
2610
2611config PCI_GOMMCONFIG
2612 bool "MMConfig"
2613
2614config PCI_GODIRECT
2615 bool "Direct"
2616
3ef0e1f8 2617config PCI_GOOLPC
76fb6570 2618 bool "OLPC XO-1"
3ef0e1f8
AS
2619 depends on OLPC
2620
2bdd1b03
AS
2621config PCI_GOANY
2622 bool "Any"
2623
e279b6c1
SR
2624endchoice
2625
2626config PCI_BIOS
3c2362e6 2627 def_bool y
efefa6f6 2628 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2629
2630# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2631config PCI_DIRECT
3c2362e6 2632 def_bool y
0aba496f 2633 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2634
2635config PCI_MMCONFIG
b45c9f36
JK
2636 bool "Support mmconfig PCI config space access" if X86_64
2637 default y
4590d98f 2638 depends on PCI && (ACPI || JAILHOUSE_GUEST)
b45c9f36 2639 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2640
3ef0e1f8 2641config PCI_OLPC
2bdd1b03
AS
2642 def_bool y
2643 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2644
b5401a96
AN
2645config PCI_XEN
2646 def_bool y
2647 depends on PCI && XEN
2648 select SWIOTLB_XEN
2649
8364e1f8
JK
2650config MMCONF_FAM10H
2651 def_bool y
2652 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2653
3f6ea84a 2654config PCI_CNB20LE_QUIRK
6a108a14 2655 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2656 depends on PCI
3f6ea84a
IS
2657 help
2658 Read the PCI windows out of the CNB20LE host bridge. This allows
2659 PCI hotplug to work on systems with the CNB20LE chipset which do
2660 not have ACPI.
2661
64a5fed6
BH
2662 There's no public spec for this chipset, and this functionality
2663 is known to be incomplete.
2664
2665 You should say N unless you know you need this.
2666
3a495511 2667config ISA_BUS
17a2a129 2668 bool "ISA bus support on modern systems" if EXPERT
3a495511 2669 help
17a2a129
WBG
2670 Expose ISA bus device drivers and options available for selection and
2671 configuration. Enable this option if your target machine has an ISA
2672 bus. ISA is an older system, displaced by PCI and newer bus
2673 architectures -- if your target machine is modern, it probably does
2674 not have an ISA bus.
3a495511
WBG
2675
2676 If unsure, say N.
2677
1c00f016 2678# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2679config ISA_DMA_API
1c00f016
DR
2680 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2681 default y
2682 help
2683 Enables ISA-style DMA support for devices requiring such controllers.
2684 If unsure, say Y.
e279b6c1 2685
51e68d05
LT
2686if X86_32
2687
e279b6c1
SR
2688config ISA
2689 bool "ISA support"
a7f7f624 2690 help
e279b6c1
SR
2691 Find out whether you have ISA slots on your motherboard. ISA is the
2692 name of a bus system, i.e. the way the CPU talks to the other stuff
2693 inside your box. Other bus systems are PCI, EISA, MicroChannel
2694 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2695 newer boards don't support it. If you have ISA, say Y, otherwise N.
2696
e279b6c1
SR
2697config SCx200
2698 tristate "NatSemi SCx200 support"
a7f7f624 2699 help
e279b6c1
SR
2700 This provides basic support for National Semiconductor's
2701 (now AMD's) Geode processors. The driver probes for the
2702 PCI-IDs of several on-chip devices, so its a good dependency
2703 for other scx200_* drivers.
2704
2705 If compiled as a module, the driver is named scx200.
2706
2707config SCx200HR_TIMER
2708 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2709 depends on SCx200
e279b6c1 2710 default y
a7f7f624 2711 help
e279b6c1
SR
2712 This driver provides a clocksource built upon the on-chip
2713 27MHz high-resolution timer. Its also a workaround for
2714 NSC Geode SC-1100's buggy TSC, which loses time when the
2715 processor goes idle (as is done by the scheduler). The
2716 other workaround is idle=poll boot option.
2717
3ef0e1f8
AS
2718config OLPC
2719 bool "One Laptop Per Child support"
54008979 2720 depends on !X86_PAE
3c554946 2721 select GPIOLIB
dc3119e7 2722 select OF
45bb1674 2723 select OF_PROMTREE
b4e51854 2724 select IRQ_DOMAIN
0c3d931b 2725 select OLPC_EC
a7f7f624 2726 help
3ef0e1f8
AS
2727 Add support for detecting the unique features of the OLPC
2728 XO hardware.
2729
a3128588
DD
2730config OLPC_XO1_PM
2731 bool "OLPC XO-1 Power Management"
fa112cf1 2732 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 2733 help
97c4cb71 2734 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2735
cfee9597
DD
2736config OLPC_XO1_RTC
2737 bool "OLPC XO-1 Real Time Clock"
2738 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 2739 help
cfee9597
DD
2740 Add support for the XO-1 real time clock, which can be used as a
2741 programmable wakeup source.
2742
7feda8e9
DD
2743config OLPC_XO1_SCI
2744 bool "OLPC XO-1 SCI extras"
92e830f2 2745 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2746 depends on INPUT=y
d8d01a63 2747 select POWER_SUPPLY
a7f7f624 2748 help
7feda8e9 2749 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2750 - EC-driven system wakeups
7feda8e9 2751 - Power button
7bc74b3d 2752 - Ebook switch
2cf2baea 2753 - Lid switch
e1040ac6
DD
2754 - AC adapter status updates
2755 - Battery status updates
7feda8e9 2756
a0f30f59
DD
2757config OLPC_XO15_SCI
2758 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2759 depends on OLPC && ACPI
2760 select POWER_SUPPLY
a7f7f624 2761 help
a0f30f59
DD
2762 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2763 - EC-driven system wakeups
2764 - AC adapter status updates
2765 - Battery status updates
bf1ebf00 2766
d4f3e350
EW
2767config ALIX
2768 bool "PCEngines ALIX System Support (LED setup)"
2769 select GPIOLIB
a7f7f624 2770 help
d4f3e350
EW
2771 This option enables system support for the PCEngines ALIX.
2772 At present this just sets up LEDs for GPIO control on
2773 ALIX2/3/6 boards. However, other system specific setup should
2774 get added here.
2775
2776 Note: You must still enable the drivers for GPIO and LED support
2777 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2778
2779 Note: You have to set alix.force=1 for boards with Award BIOS.
2780
da4e3302
PP
2781config NET5501
2782 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2783 select GPIOLIB
a7f7f624 2784 help
da4e3302
PP
2785 This option enables system support for the Soekris Engineering net5501.
2786
3197059a
PP
2787config GEOS
2788 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2789 select GPIOLIB
2790 depends on DMI
a7f7f624 2791 help
3197059a
PP
2792 This option enables system support for the Traverse Technologies GEOS.
2793
7d029125
VD
2794config TS5500
2795 bool "Technologic Systems TS-5500 platform support"
2796 depends on MELAN
2797 select CHECK_SIGNATURE
2798 select NEW_LEDS
2799 select LEDS_CLASS
a7f7f624 2800 help
7d029125
VD
2801 This option enables system support for the Technologic Systems TS-5500.
2802
bc0120fd
SR
2803endif # X86_32
2804
23ac4ae8 2805config AMD_NB
e279b6c1 2806 def_bool y
0e152cd7 2807 depends on CPU_SUP_AMD && PCI
e279b6c1 2808
e3263ab3
DH
2809config X86_SYSFB
2810 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2811 help
2812 Firmwares often provide initial graphics framebuffers so the BIOS,
2813 bootloader or kernel can show basic video-output during boot for
2814 user-guidance and debugging. Historically, x86 used the VESA BIOS
2815 Extensions and EFI-framebuffers for this, which are mostly limited
2816 to x86.
2817 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2818 framebuffers so the new generic system-framebuffer drivers can be
2819 used on x86. If the framebuffer is not compatible with the generic
e3a5dc08 2820 modes, it is advertised as fallback platform framebuffer so legacy
e3263ab3
DH
2821 drivers like efifb, vesafb and uvesafb can pick it up.
2822 If this option is not selected, all system framebuffers are always
2823 marked as fallback platform framebuffers as usual.
2824
2825 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2826 not be able to pick up generic system framebuffers if this option
2827 is selected. You are highly encouraged to enable simplefb as
2828 replacement if you select this option. simplefb can correctly deal
2829 with generic system framebuffers. But you should still keep vesafb
2830 and others enabled as fallback if a system framebuffer is
2831 incompatible with simplefb.
2832
2833 If unsure, say Y.
2834
e279b6c1
SR
2835endmenu
2836
2837
1572497c 2838menu "Binary Emulations"
e279b6c1
SR
2839
2840config IA32_EMULATION
2841 bool "IA32 Emulation"
2842 depends on X86_64
39f88911 2843 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2844 select BINFMT_ELF
39f88911 2845 select COMPAT_OLD_SIGACTION
a7f7f624 2846 help
5fd92e65
L
2847 Include code to run legacy 32-bit programs under a
2848 64-bit kernel. You should likely turn this on, unless you're
2849 100% sure that you don't have any 32-bit programs left.
e279b6c1
SR
2850
2851config IA32_AOUT
8f9ca475
IM
2852 tristate "IA32 a.out support"
2853 depends on IA32_EMULATION
eac61655 2854 depends on BROKEN
a7f7f624 2855 help
8f9ca475 2856 Support old a.out binaries in the 32bit emulation.
e279b6c1 2857
0bf62763 2858config X86_X32
6ea30386 2859 bool "x32 ABI for 64-bit mode"
9b54050b 2860 depends on X86_64
a7f7f624 2861 help
5fd92e65
L
2862 Include code to run binaries for the x32 native 32-bit ABI
2863 for 64-bit processors. An x32 process gets access to the
2864 full 64-bit register file and wide data path while leaving
2865 pointers at 32 bits for smaller memory footprint.
2866
2867 You will need a recent binutils (2.22 or later) with
2868 elf32_x86_64 support enabled to compile a kernel with this
2869 option set.
2870
953fee1d
IM
2871config COMPAT_32
2872 def_bool y
2873 depends on IA32_EMULATION || X86_32
2874 select HAVE_UID16
2875 select OLD_SIGSUSPEND3
2876
e279b6c1 2877config COMPAT
3c2362e6 2878 def_bool y
0bf62763 2879 depends on IA32_EMULATION || X86_X32
e279b6c1 2880
3120e25e 2881if COMPAT
e279b6c1 2882config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2883 def_bool y
e279b6c1
SR
2884
2885config SYSVIPC_COMPAT
3c2362e6 2886 def_bool y
3120e25e 2887 depends on SYSVIPC
3120e25e 2888endif
ee009e4a 2889
e279b6c1
SR
2890endmenu
2891
2892
e5beae16
KP
2893config HAVE_ATOMIC_IOMAP
2894 def_bool y
2895 depends on X86_32
2896
e279b6c1
SR
2897source "drivers/firmware/Kconfig"
2898
edf88417 2899source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
2900
2901source "arch/x86/Kconfig.assembler"